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diff --git a/widget/BasicEvents.h b/widget/BasicEvents.h
new file mode 100644
index 0000000000..b3707f1cf4
--- /dev/null
+++ b/widget/BasicEvents.h
@@ -0,0 +1,1335 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_BasicEvents_h__
+#define mozilla_BasicEvents_h__
+
+#include <stdint.h>
+#include <type_traits>
+
+#include "mozilla/EventForwards.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/dom/EventTarget.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "nsCOMPtr.h"
+#include "nsAtom.h"
+#include "nsISupportsImpl.h"
+#include "nsIWidget.h"
+#include "nsString.h"
+#include "Units.h"
+
+#ifdef DEBUG
+#  include "nsXULAppAPI.h"
+#endif  // #ifdef DEBUG
+
+class nsIPrincipal;
+
+namespace IPC {
+template <typename T>
+struct ParamTraits;
+}  // namespace IPC
+
+namespace mozilla {
+
+class EventTargetChainItem;
+
+enum class CrossProcessForwarding {
+  // eStop prevents the event to be sent to remote process.
+  eStop,
+  // eAllow keeps current state of the event whether it's sent to remote
+  // process.  In other words, eAllow does NOT mean that making the event
+  // sent to remote process when IsCrossProcessForwardingStopped() returns
+  // true.
+  eAllow,
+};
+
+/******************************************************************************
+ * mozilla::BaseEventFlags
+ *
+ * BaseEventFlags must be a POD struct for safe to use memcpy (including
+ * in ParamTraits<BaseEventFlags>).  So don't make virtual methods, constructor,
+ * destructor and operators.
+ * This is necessary for VC which is NOT C++0x compiler.
+ ******************************************************************************/
+
+struct BaseEventFlags {
+ public:
+  // If mIsTrusted is true, the event is a trusted event.  Otherwise, it's
+  // an untrusted event.
+  bool mIsTrusted : 1;
+  // If mInBubblingPhase is true, the event is in bubbling phase or target
+  // phase.
+  bool mInBubblingPhase : 1;
+  // If mInCapturePhase is true, the event is in capture phase or target phase.
+  bool mInCapturePhase : 1;
+  // If mInTargetPhase is true, the event is in target phase.
+  bool mInTargetPhase : 1;
+  // If mInSystemGroup is true, the event is being dispatched in system group.
+  bool mInSystemGroup : 1;
+  // If mCancelable is true, the event can be consumed.  I.e., calling
+  // dom::Event::PreventDefault() can prevent the default action.
+  bool mCancelable : 1;
+  // If mBubbles is true, the event can bubble.  Otherwise, cannot be handled
+  // in bubbling phase.
+  bool mBubbles : 1;
+  // If mPropagationStopped is true, dom::Event::StopPropagation() or
+  // dom::Event::StopImmediatePropagation() has been called.
+  bool mPropagationStopped : 1;
+  // If mImmediatePropagationStopped is true,
+  // dom::Event::StopImmediatePropagation() has been called.
+  // Note that mPropagationStopped must be true when this is true.
+  bool mImmediatePropagationStopped : 1;
+  // If mDefaultPrevented is true, the event has been consumed.
+  // E.g., dom::Event::PreventDefault() has been called or
+  // the default action has been performed.
+  bool mDefaultPrevented : 1;
+  // If mDefaultPreventedByContent is true, the event has been
+  // consumed by content.
+  // Note that mDefaultPrevented must be true when this is true.
+  bool mDefaultPreventedByContent : 1;
+  // If mDefaultPreventedByChrome is true, the event has been
+  // consumed by chrome.
+  // Note that mDefaultPrevented must be true when this is true.
+  bool mDefaultPreventedByChrome : 1;
+  // mMultipleActionsPrevented may be used when default handling don't want to
+  // be prevented, but only one of the event targets should handle the event.
+  // For example, when a <label> element is in another <label> element and
+  // the first <label> element is clicked, that one may set this true.
+  // Then, the second <label> element won't handle the event.
+  bool mMultipleActionsPrevented : 1;
+  // If mIsBeingDispatched is true, the DOM event created from the event is
+  // dispatching into the DOM tree and not completed.
+  bool mIsBeingDispatched : 1;
+  // If mDispatchedAtLeastOnce is true, the event has been dispatched
+  // as a DOM event and the dispatch has been completed in the process.
+  // So, this is false even if the event has already been dispatched
+  // in another process.
+  bool mDispatchedAtLeastOnce : 1;
+  // If mIsSynthesizedForTests is true, the event has been synthesized for
+  // automated tests or something hacky approach of an add-on.
+  bool mIsSynthesizedForTests : 1;
+  // If mExceptionWasRaised is true, one of the event handlers has raised an
+  // exception.
+  bool mExceptionWasRaised : 1;
+  // If mRetargetToNonNativeAnonymous is true and the target is in a non-native
+  // native anonymous subtree, the event target is set to mOriginalTarget.
+  bool mRetargetToNonNativeAnonymous : 1;
+  // If mNoContentDispatch is true, the event is never dispatched to the
+  // event handlers which are added to the contents, onfoo attributes and
+  // properties.  Note that this flag is ignored when
+  // EventChainPreVisitor::mForceContentDispatch is set true.  For exapmle,
+  // window and document object sets it true.  Therefore, web applications
+  // can handle the event if they add event listeners to the window or the
+  // document.
+  // XXX This is an ancient and broken feature, don't use this for new bug
+  //     as far as possible.
+  bool mNoContentDispatch : 1;
+  // If mOnlyChromeDispatch is true, the event is dispatched to only chrome.
+  bool mOnlyChromeDispatch : 1;
+  // Indicates if the key combination is reserved by chrome.  This is set by
+  // MarkAsReservedByChrome().
+  bool mIsReservedByChrome : 1;
+  // If mOnlySystemGroupDispatchInContent is true, event listeners added to
+  // the default group for non-chrome EventTarget won't be called.
+  // Be aware, if this is true, EventDispatcher needs to check if each event
+  // listener is added to chrome node, so, don't set this to true for the
+  // events which are fired a lot of times like eMouseMove.
+  bool mOnlySystemGroupDispatchInContent : 1;
+  // If mOnlySystemGroupDispatch is true, the event will be dispatched only to
+  // event listeners added in the system group.
+  bool mOnlySystemGroupDispatch : 1;
+  // The event's action will be handled by APZ. The main thread should not
+  // perform its associated action.
+  bool mHandledByAPZ : 1;
+  // True if the event is currently being handled by an event listener that
+  // was registered as a passive listener.
+  bool mInPassiveListener : 1;
+  // If mComposed is true, the event fired by nodes in shadow DOM can cross the
+  // boundary of shadow DOM and light DOM.
+  bool mComposed : 1;
+  // Similar to mComposed. Set it to true to allow events cross the boundary
+  // between native non-anonymous content and native anonymouse content
+  bool mComposedInNativeAnonymousContent : 1;
+  // Set to true for events which are suppressed or delayed so that later a
+  // DelayedEvent of it is dispatched. This is used when parent side process
+  // the key event after content side, and may drop the event if the event
+  // was suppressed or delayed in contents side.
+  // It is also set to true for the events (in a DelayedInputEvent), which will
+  // be dispatched afterwards.
+  bool mIsSuppressedOrDelayed : 1;
+  // Certain mouse events can be marked as positionless to return 0 from
+  // coordinate related getters.
+  bool mIsPositionless : 1;
+
+  // Flags managing state of propagation between processes.
+  // Note the the following flags shouldn't be referred directly.  Use utility
+  // methods instead.
+
+  // If mNoRemoteProcessDispatch is true, the event is not allowed to be sent
+  // to remote process.
+  bool mNoRemoteProcessDispatch : 1;
+  // If mWantReplyFromContentProcess is true, the event will be redispatched
+  // in the parent process after the content process has handled it. Useful
+  // for when the parent process need the know first how the event was used
+  // by content before handling it itself.
+  bool mWantReplyFromContentProcess : 1;
+  // If mPostedToRemoteProcess is true, the event has been posted to the
+  // remote process (but it's not handled yet if it's not a duplicated event
+  // instance).
+  bool mPostedToRemoteProcess : 1;
+  // If mCameFromAnotherProcess is true, the event came from another process.
+  bool mCameFromAnotherProcess : 1;
+
+  /**
+   * Helper methods for methods of DOM Event.
+   */
+  inline void StopPropagation() { mPropagationStopped = true; }
+  inline void StopImmediatePropagation() {
+    StopPropagation();
+    mImmediatePropagationStopped = true;
+  }
+  inline void PreventDefault(bool aCalledByDefaultHandler = true) {
+    if (!mCancelable) {
+      return;
+    }
+    mDefaultPrevented = true;
+    // Note that even if preventDefault() has already been called by chrome,
+    // a call of preventDefault() by content needs to overwrite
+    // mDefaultPreventedByContent to true because in such case, defaultPrevented
+    // must be true when web apps check it after they call preventDefault().
+    if (aCalledByDefaultHandler) {
+      StopCrossProcessForwarding();
+      mDefaultPreventedByChrome = true;
+    } else {
+      mDefaultPreventedByContent = true;
+    }
+  }
+  // This should be used only before dispatching events into the DOM tree.
+  inline void PreventDefaultBeforeDispatch(
+      CrossProcessForwarding aCrossProcessForwarding) {
+    if (!mCancelable) {
+      return;
+    }
+    mDefaultPrevented = true;
+    if (aCrossProcessForwarding == CrossProcessForwarding::eStop) {
+      StopCrossProcessForwarding();
+    }
+  }
+  inline bool DefaultPrevented() const { return mDefaultPrevented; }
+  inline bool DefaultPreventedByContent() const {
+    MOZ_ASSERT(!mDefaultPreventedByContent || DefaultPrevented());
+    return mDefaultPreventedByContent;
+  }
+  inline bool IsTrusted() const { return mIsTrusted; }
+  inline bool PropagationStopped() const { return mPropagationStopped; }
+
+  // Helper methods to access flags managing state of propagation between
+  // processes.
+
+  /**
+   * Prevent to be dispatched to remote process.
+   */
+  inline void StopCrossProcessForwarding() {
+    MOZ_ASSERT(!mPostedToRemoteProcess);
+    mNoRemoteProcessDispatch = true;
+    mWantReplyFromContentProcess = false;
+  }
+  /**
+   * Return true if the event shouldn't be dispatched to remote process.
+   */
+  inline bool IsCrossProcessForwardingStopped() const {
+    return mNoRemoteProcessDispatch;
+  }
+  /**
+   * Mark the event as waiting reply from remote process.
+   * If the caller needs to win other keyboard event handlers in chrome,
+   * the caller should call StopPropagation() too.
+   * Otherwise, if the caller just needs to know if the event is consumed by
+   * either content or chrome, it should just call this because the event
+   * may be reserved by chrome and it needs to be dispatched into the DOM
+   * tree in chrome for checking if it's reserved before being sent to any
+   * remote processes.
+   */
+  inline void MarkAsWaitingReplyFromRemoteProcess() {
+    MOZ_ASSERT(!mPostedToRemoteProcess);
+    mNoRemoteProcessDispatch = false;
+    mWantReplyFromContentProcess = true;
+  }
+  /**
+   * Reset "waiting reply from remote process" state.  This is useful when
+   * you dispatch a copy of an event coming from different process.
+   */
+  inline void ResetWaitingReplyFromRemoteProcessState() {
+    if (IsWaitingReplyFromRemoteProcess()) {
+      // FYI: mWantReplyFromContentProcess is also used for indicating
+      //      "handled in remote process" state.  Therefore, only when
+      //      IsWaitingReplyFromRemoteProcess() returns true, this should
+      //      reset the flag.
+      mWantReplyFromContentProcess = false;
+    }
+  }
+  /**
+   * Return true if the event handler should wait reply event.  I.e., if this
+   * returns true, any event handler should do nothing with the event.
+   */
+  inline bool IsWaitingReplyFromRemoteProcess() const {
+    return !mNoRemoteProcessDispatch && mWantReplyFromContentProcess;
+  }
+  /**
+   * Mark the event as already handled in the remote process.  This should be
+   * called when initializing reply events.
+   */
+  inline void MarkAsHandledInRemoteProcess() {
+    mNoRemoteProcessDispatch = true;
+    mWantReplyFromContentProcess = true;
+    mPostedToRemoteProcess = false;
+  }
+  /**
+   * Return true if the event has already been handled in the remote process.
+   */
+  inline bool IsHandledInRemoteProcess() const {
+    return mNoRemoteProcessDispatch && mWantReplyFromContentProcess;
+  }
+  /**
+   * Return true if the event should be sent back to its parent process.
+   */
+  inline bool WantReplyFromContentProcess() const {
+    MOZ_ASSERT(!XRE_IsParentProcess());
+    return IsWaitingReplyFromRemoteProcess();
+  }
+  /**
+   * Mark the event has already posted to a remote process.
+   */
+  inline void MarkAsPostedToRemoteProcess() {
+    MOZ_ASSERT(!IsCrossProcessForwardingStopped());
+    mPostedToRemoteProcess = true;
+  }
+  /**
+   * Reset the cross process dispatching state.  This should be used when a
+   * process receives the event because the state is in the sender.
+   */
+  inline void ResetCrossProcessDispatchingState() {
+    MOZ_ASSERT(!IsCrossProcessForwardingStopped());
+    mPostedToRemoteProcess = false;
+    // Ignore propagation state in the remote process if it's marked as
+    // "waiting reply from remote process" because the process needs to
+    // stop propagation in the process until receiving a reply event.
+    // Note that the propagation stopped flag is important for the reply event
+    // handler in the main process because it's used for making whether it's
+    // ignored by the remote process or not.
+    if (!XRE_IsParentProcess() && IsWaitingReplyFromRemoteProcess()) {
+      mPropagationStopped = mImmediatePropagationStopped = false;
+    }
+    // mDispatchedAtLeastOnce indicates the state in current process.
+    mDispatchedAtLeastOnce = false;
+  }
+  /**
+   * Return true if the event has been posted to a remote process.
+   * Note that MarkAsPostedToRemoteProcess() is called by
+   * ParamTraits<mozilla::WidgetEvent>.  Therefore, it *might* be possible
+   * that posting the event failed even if this returns true.  But that must
+   * really rare.  If that'd be problem for you, you should unmark this in
+   * BrowserParent or somewhere.
+   */
+  inline bool HasBeenPostedToRemoteProcess() const {
+    return mPostedToRemoteProcess;
+  }
+  /**
+   * Return true if the event came from another process.
+   */
+  inline bool CameFromAnotherProcess() const { return mCameFromAnotherProcess; }
+  /**
+   * Mark the event as coming from another process.
+   */
+  inline void MarkAsComingFromAnotherProcess() {
+    mCameFromAnotherProcess = true;
+  }
+  /**
+   * Mark the event is reserved by chrome.  I.e., shouldn't be dispatched to
+   * content because it shouldn't be cancelable.
+   */
+  inline void MarkAsReservedByChrome() {
+    MOZ_ASSERT(!mPostedToRemoteProcess);
+    mIsReservedByChrome = true;
+    // For reserved commands (such as Open New Tab), we don't need to wait for
+    // the content to answer, neither to give a chance for content to override
+    // its behavior.
+    StopCrossProcessForwarding();
+    // If the event is reserved by chrome, we shouldn't expose the event to
+    // web contents because such events shouldn't be cancelable.  So, it's not
+    // good behavior to fire such events but to ignore the defaultPrevented
+    // attribute value in chrome.
+    mOnlySystemGroupDispatchInContent = true;
+  }
+  /**
+   * Return true if the event is reserved by chrome.
+   */
+  inline bool IsReservedByChrome() const {
+    MOZ_ASSERT(!mIsReservedByChrome || (IsCrossProcessForwardingStopped() &&
+                                        mOnlySystemGroupDispatchInContent));
+    return mIsReservedByChrome;
+  }
+
+  inline void Clear() { SetRawFlags(0); }
+  // Get if either the instance's bit or the aOther's bit is true, the
+  // instance's bit becomes true.  In other words, this works like:
+  // eventFlags |= aOther;
+  inline void Union(const BaseEventFlags& aOther) {
+    RawFlags rawFlags = GetRawFlags() | aOther.GetRawFlags();
+    SetRawFlags(rawFlags);
+  }
+
+ private:
+  typedef uint64_t RawFlags;
+
+  inline void SetRawFlags(RawFlags aRawFlags) {
+    static_assert(sizeof(BaseEventFlags) <= sizeof(RawFlags),
+                  "mozilla::EventFlags must not be bigger than the RawFlags");
+    memcpy(this, &aRawFlags, sizeof(BaseEventFlags));
+  }
+  inline RawFlags GetRawFlags() const {
+    RawFlags result = 0;
+    memcpy(&result, this, sizeof(BaseEventFlags));
+    return result;
+  }
+};
+
+/******************************************************************************
+ * mozilla::EventFlags
+ ******************************************************************************/
+
+struct EventFlags : public BaseEventFlags {
+  EventFlags() { Clear(); }
+};
+
+/******************************************************************************
+ * mozilla::WidgetEventTime
+ ******************************************************************************/
+
+class WidgetEventTime {
+ public:
+  // Timestamp when the message was created.
+  TimeStamp mTimeStamp;
+
+  WidgetEventTime() : mTimeStamp(TimeStamp::Now()) {}
+
+  explicit WidgetEventTime(const WidgetEventTime* aTime)
+      : mTimeStamp(aTime ? aTime->mTimeStamp : TimeStamp::Now()) {
+    MOZ_ASSERT(aTime != this);
+    MOZ_ASSERT_IF(aTime, !aTime->mTimeStamp.IsNull());
+  }
+
+  explicit WidgetEventTime(TimeStamp aTimeStamp) : mTimeStamp(aTimeStamp) {}
+
+  void AssignEventTime(const WidgetEventTime& aOther) {
+    mTimeStamp = aOther.mTimeStamp;
+  }
+};
+
+/******************************************************************************
+ * mozilla::WidgetEvent
+ ******************************************************************************/
+
+class WidgetEvent : public WidgetEventTime {
+ private:
+  void SetDefaultCancelableAndBubbles() {
+    switch (mClass) {
+      case eEditorInputEventClass:
+        mFlags.mCancelable = false;
+        mFlags.mBubbles = mFlags.mIsTrusted;
+        break;
+      case eMouseEventClass:
+        mFlags.mCancelable =
+            (mMessage != eMouseEnter && mMessage != eMouseLeave);
+        mFlags.mBubbles = (mMessage != eMouseEnter && mMessage != eMouseLeave);
+        break;
+      case ePointerEventClass:
+        mFlags.mCancelable =
+            (mMessage != ePointerEnter && mMessage != ePointerLeave &&
+             mMessage != ePointerCancel && mMessage != ePointerGotCapture &&
+             mMessage != ePointerLostCapture);
+        mFlags.mBubbles =
+            (mMessage != ePointerEnter && mMessage != ePointerLeave);
+        break;
+      case eDragEventClass:
+        mFlags.mCancelable = (mMessage != eDragExit && mMessage != eDragLeave &&
+                              mMessage != eDragEnd);
+        mFlags.mBubbles = true;
+        break;
+      case eSMILTimeEventClass:
+        mFlags.mCancelable = false;
+        mFlags.mBubbles = false;
+        break;
+      case eTransitionEventClass:
+      case eAnimationEventClass:
+        mFlags.mCancelable = false;
+        mFlags.mBubbles = true;
+        break;
+      case eCompositionEventClass:
+        // XXX compositionstart is cancelable in draft of DOM3 Events.
+        //     However, it doesn't make sense for us, we cannot cancel
+        //     composition when we send compositionstart event.
+        mFlags.mCancelable = false;
+        mFlags.mBubbles = true;
+        break;
+      default:
+        if (mMessage == eResize || mMessage == eMozVisualResize ||
+            mMessage == eMozVisualScroll || mMessage == eEditorInput ||
+            mMessage == eFormSelect) {
+          mFlags.mCancelable = false;
+        } else {
+          mFlags.mCancelable = true;
+        }
+        mFlags.mBubbles = true;
+        break;
+    }
+  }
+
+ protected:
+  WidgetEvent(bool aIsTrusted, EventMessage aMessage,
+              EventClassID aEventClassID,
+              const WidgetEventTime* aTime = nullptr)
+      : WidgetEventTime(aTime),
+        mClass(aEventClassID),
+        mMessage(aMessage),
+        mRefPoint(0, 0),
+        mLastRefPoint(0, 0),
+        mFocusSequenceNumber(0),
+        mSpecifiedEventType(nullptr),
+        mPath(nullptr),
+        mLayersId(layers::LayersId{0}) {
+    MOZ_COUNT_CTOR(WidgetEvent);
+    mFlags.Clear();
+    mFlags.mIsTrusted = aIsTrusted;
+    SetDefaultCancelableAndBubbles();
+    SetDefaultComposed();
+    SetDefaultComposedInNativeAnonymousContent();
+  }
+
+  WidgetEvent() : mPath(nullptr) { MOZ_COUNT_CTOR(WidgetEvent); }
+
+ public:
+  WidgetEvent(bool aIsTrusted, EventMessage aMessage,
+              const WidgetEventTime* aTime = nullptr)
+      : WidgetEvent(aIsTrusted, aMessage, eBasicEventClass, aTime) {}
+
+  MOZ_COUNTED_DTOR_VIRTUAL(WidgetEvent)
+
+  WidgetEvent(const WidgetEvent& aOther) : WidgetEventTime(aOther) {
+    MOZ_COUNT_CTOR(WidgetEvent);
+    *this = aOther;
+  }
+  WidgetEvent& operator=(const WidgetEvent& aOther) = default;
+
+  WidgetEvent(WidgetEvent&& aOther)
+      : WidgetEventTime(std::move(aOther)),
+        mClass(aOther.mClass),
+        mMessage(aOther.mMessage),
+        mRefPoint(std::move(aOther.mRefPoint)),
+        mLastRefPoint(std::move(aOther.mLastRefPoint)),
+        mFocusSequenceNumber(aOther.mFocusSequenceNumber),
+        mFlags(std::move(aOther.mFlags)),
+        mSpecifiedEventType(std::move(aOther.mSpecifiedEventType)),
+        mSpecifiedEventTypeString(std::move(aOther.mSpecifiedEventTypeString)),
+        mTarget(std::move(aOther.mTarget)),
+        mCurrentTarget(std::move(aOther.mCurrentTarget)),
+        mOriginalTarget(std::move(aOther.mOriginalTarget)),
+        mRelatedTarget(std::move(aOther.mRelatedTarget)),
+        mOriginalRelatedTarget(std::move(aOther.mOriginalRelatedTarget)),
+        mPath(std::move(aOther.mPath)) {
+    MOZ_COUNT_CTOR(WidgetEvent);
+  }
+  WidgetEvent& operator=(WidgetEvent&& aOther) = default;
+
+  virtual WidgetEvent* Duplicate() const {
+    MOZ_ASSERT(mClass == eBasicEventClass,
+               "Duplicate() must be overridden by sub class");
+    WidgetEvent* result = new WidgetEvent(false, mMessage, this);
+    result->AssignEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  EventClassID mClass;
+  EventMessage mMessage;
+  // Relative to the widget of the event, or if there is no widget then it is
+  // in screen coordinates. Not modified by layout code.
+  // This is in visual coordinates, i.e. the correct RelativeTo value that
+  // expresses what this is relative to is `{viewportFrame, Visual}`, where
+  // `viewportFrame` is the viewport frame of the widget's root document.
+  LayoutDeviceIntPoint mRefPoint;
+  // The previous mRefPoint, if known, used to calculate mouse movement deltas.
+  LayoutDeviceIntPoint mLastRefPoint;
+  // The sequence number of the last potentially focus changing event handled
+  // by APZ. This is used to track when that event has been processed by
+  // content, and focus can be reconfirmed for async keyboard scrolling.
+  uint64_t mFocusSequenceNumber;
+  // See BaseEventFlags definition for the detail.
+  BaseEventFlags mFlags;
+
+  // If JS creates an event with unknown event type or known event type but
+  // for different event interface, the event type is stored to this.
+  // NOTE: This is always used if the instance is a WidgetCommandEvent instance
+  //       or "input" event is dispatched with dom::Event class.
+  RefPtr<nsAtom> mSpecifiedEventType;
+
+  // nsAtom isn't available on non-main thread due to unsafe.  Therefore,
+  // mSpecifiedEventTypeString is used instead of mSpecifiedEventType if
+  // the event is created in non-main thread.
+  nsString mSpecifiedEventTypeString;
+
+  // Event targets, needed by DOM Events
+  // Note that when you need event target for DOM event, you should use
+  // Get*DOMEventTarget() instead of accessing these members directly.
+  nsCOMPtr<dom::EventTarget> mTarget;
+  nsCOMPtr<dom::EventTarget> mCurrentTarget;
+  nsCOMPtr<dom::EventTarget> mOriginalTarget;
+
+  /// The possible related target
+  nsCOMPtr<dom::EventTarget> mRelatedTarget;
+  nsCOMPtr<dom::EventTarget> mOriginalRelatedTarget;
+
+  nsTArray<EventTargetChainItem>* mPath;
+
+  // The LayersId of the content process that this event should be
+  // dispatched to. This field is only used in the chrome process
+  // and doesn't get remoted to child processes.
+  layers::LayersId mLayersId;
+
+  dom::EventTarget* GetDOMEventTarget() const;
+  dom::EventTarget* GetCurrentDOMEventTarget() const;
+  dom::EventTarget* GetOriginalDOMEventTarget() const;
+
+  void AssignEventData(const WidgetEvent& aEvent, bool aCopyTargets) {
+    // mClass should be initialized with the constructor.
+    // mMessage should be initialized with the constructor.
+    mRefPoint = aEvent.mRefPoint;
+    // mLastRefPoint doesn't need to be copied.
+    mFocusSequenceNumber = aEvent.mFocusSequenceNumber;
+    // mLayersId intentionally not copied, since it's not used within content
+    AssignEventTime(aEvent);
+    // mFlags should be copied manually if it's necessary.
+    mSpecifiedEventType = aEvent.mSpecifiedEventType;
+    // mSpecifiedEventTypeString should be copied manually if it's necessary.
+    mTarget = aCopyTargets ? aEvent.mTarget : nullptr;
+    mCurrentTarget = aCopyTargets ? aEvent.mCurrentTarget : nullptr;
+    mOriginalTarget = aCopyTargets ? aEvent.mOriginalTarget : nullptr;
+    mRelatedTarget = aCopyTargets ? aEvent.mRelatedTarget : nullptr;
+    mOriginalRelatedTarget =
+        aCopyTargets ? aEvent.mOriginalRelatedTarget : nullptr;
+  }
+
+  /**
+   * Helper methods for methods of DOM Event.
+   */
+  void StopPropagation() { mFlags.StopPropagation(); }
+  void StopImmediatePropagation() { mFlags.StopImmediatePropagation(); }
+  void PreventDefault(bool aCalledByDefaultHandler = true,
+                      nsIPrincipal* aPrincipal = nullptr);
+
+  void PreventDefaultBeforeDispatch(
+      CrossProcessForwarding aCrossProcessForwarding) {
+    mFlags.PreventDefaultBeforeDispatch(aCrossProcessForwarding);
+  }
+  bool DefaultPrevented() const { return mFlags.DefaultPrevented(); }
+  bool DefaultPreventedByContent() const {
+    return mFlags.DefaultPreventedByContent();
+  }
+  bool IsTrusted() const { return mFlags.IsTrusted(); }
+  bool PropagationStopped() const { return mFlags.PropagationStopped(); }
+
+  /**
+   * Prevent to be dispatched to remote process.
+   */
+  inline void StopCrossProcessForwarding() {
+    mFlags.StopCrossProcessForwarding();
+  }
+  /**
+   * Return true if the event shouldn't be dispatched to remote process.
+   */
+  inline bool IsCrossProcessForwardingStopped() const {
+    return mFlags.IsCrossProcessForwardingStopped();
+  }
+  /**
+   * Mark the event as waiting reply from remote process.
+   * Note that this also stops immediate propagation in current process.
+   */
+  inline void MarkAsWaitingReplyFromRemoteProcess() {
+    mFlags.MarkAsWaitingReplyFromRemoteProcess();
+  }
+  /**
+   * Reset "waiting reply from remote process" state.  This is useful when
+   * you dispatch a copy of an event coming from different process.
+   */
+  inline void ResetWaitingReplyFromRemoteProcessState() {
+    mFlags.ResetWaitingReplyFromRemoteProcessState();
+  }
+  /**
+   * Return true if the event handler should wait reply event.  I.e., if this
+   * returns true, any event handler should do nothing with the event.
+   */
+  inline bool IsWaitingReplyFromRemoteProcess() const {
+    return mFlags.IsWaitingReplyFromRemoteProcess();
+  }
+  /**
+   * Mark the event as already handled in the remote process.  This should be
+   * called when initializing reply events.
+   */
+  inline void MarkAsHandledInRemoteProcess() {
+    mFlags.MarkAsHandledInRemoteProcess();
+  }
+  /**
+   * Return true if the event has already been handled in the remote process.
+   * I.e., if this returns true, the event is a reply event.
+   */
+  inline bool IsHandledInRemoteProcess() const {
+    return mFlags.IsHandledInRemoteProcess();
+  }
+  /**
+   * Return true if the event should be sent back to its parent process.
+   * So, usual event handlers shouldn't call this.
+   */
+  inline bool WantReplyFromContentProcess() const {
+    return mFlags.WantReplyFromContentProcess();
+  }
+  /**
+   * Mark the event has already posted to a remote process.
+   */
+  inline void MarkAsPostedToRemoteProcess() {
+    mFlags.MarkAsPostedToRemoteProcess();
+  }
+  /**
+   * Reset the cross process dispatching state.  This should be used when a
+   * process receives the event because the state is in the sender.
+   */
+  inline void ResetCrossProcessDispatchingState() {
+    mFlags.ResetCrossProcessDispatchingState();
+  }
+  /**
+   * Return true if the event has been posted to a remote process.
+   */
+  inline bool HasBeenPostedToRemoteProcess() const {
+    return mFlags.HasBeenPostedToRemoteProcess();
+  }
+  /**
+   * Return true if the event came from another process.
+   */
+  inline bool CameFromAnotherProcess() const {
+    return mFlags.CameFromAnotherProcess();
+  }
+  /**
+   * Mark the event as coming from another process.
+   */
+  inline void MarkAsComingFromAnotherProcess() {
+    mFlags.MarkAsComingFromAnotherProcess();
+  }
+  /**
+   * Mark the event is reserved by chrome.  I.e., shouldn't be dispatched to
+   * content because it shouldn't be cancelable.
+   */
+  inline void MarkAsReservedByChrome() { mFlags.MarkAsReservedByChrome(); }
+  /**
+   * Return true if the event is reserved by chrome.
+   */
+  inline bool IsReservedByChrome() const { return mFlags.IsReservedByChrome(); }
+
+  /**
+   * Utils for checking event types
+   */
+
+  /**
+   * As*Event() returns the pointer of the instance only when the instance is
+   * the class or one of its derived class.
+   */
+#define NS_ROOT_EVENT_CLASS(aPrefix, aName)
+#define NS_EVENT_CLASS(aPrefix, aName) \
+  virtual aPrefix##aName* As##aName(); \
+  const aPrefix##aName* As##aName() const;
+
+#include "mozilla/EventClassList.h"
+
+#undef NS_EVENT_CLASS
+#undef NS_ROOT_EVENT_CLASS
+
+  /**
+   * Returns true if the event is a query content event.
+   */
+  bool IsQueryContentEvent() const;
+  /**
+   * Returns true if the event is a selection event.
+   */
+  bool IsSelectionEvent() const;
+  /**
+   * Returns true if the event is a content command event.
+   */
+  bool IsContentCommandEvent() const;
+
+  /**
+   * Returns true if the event mMessage is one of mouse events.
+   */
+  bool HasMouseEventMessage() const;
+  /**
+   * Returns true if the event mMessage is one of drag events.
+   */
+  bool HasDragEventMessage() const;
+  /**
+   * Returns true if aMessage or mMessage is one of key events.
+   */
+  static bool IsKeyEventMessage(EventMessage aMessage);
+  bool HasKeyEventMessage() const { return IsKeyEventMessage(mMessage); }
+  /**
+   * Returns true if the event mMessage is one of composition events or text
+   * event.
+   */
+  bool HasIMEEventMessage() const;
+
+  /**
+   * Returns true if the event can be sent to remote process.
+   */
+  bool CanBeSentToRemoteProcess() const;
+  /**
+   * Returns true if the original target is a remote process and the event
+   * will be posted to the remote process later.
+   */
+  bool WillBeSentToRemoteProcess() const;
+  /**
+   * Returns true if the event is related to IME handling.  It includes
+   * IME events, query content events and selection events.
+   * Be careful when you use this.
+   */
+  bool IsIMERelatedEvent() const;
+
+  /**
+   * Whether the event should be handled by the frame of the mouse cursor
+   * position or not.  When it should be handled there (e.g., the mouse events),
+   * this returns true.
+   */
+  bool IsUsingCoordinates() const;
+  /**
+   * Whether the event should be handled by the focused DOM window in the
+   * same top level window's or not.  E.g., key events, IME related events
+   * (including the query content events, they are used in IME transaction)
+   * should be handled by the (last) focused window rather than the dispatched
+   * window.
+   *
+   * NOTE: Even if this returns true, the event isn't going to be handled by the
+   * application level active DOM window which is on another top level window.
+   * So, when the event is fired on a deactive window, the event is going to be
+   * handled by the last focused DOM window in the last focused window.
+   */
+  bool IsTargetedAtFocusedWindow() const;
+  /**
+   * Whether the event should be handled by the focused content or not.  E.g.,
+   * key events, IME related events and other input events which are not handled
+   * by the frame of the mouse cursor position.
+   *
+   * NOTE: Even if this returns true, the event isn't going to be handled by the
+   * application level active DOM window which is on another top level window.
+   * So, when the event is fired on a deactive window, the event is going to be
+   * handled by the last focused DOM element of the last focused DOM window in
+   * the last focused window.
+   */
+  bool IsTargetedAtFocusedContent() const;
+  /**
+   * Whether the event should cause a DOM event.
+   */
+  bool IsAllowedToDispatchDOMEvent() const;
+  /**
+   * Whether the event should be dispatched in system group.
+   */
+  bool IsAllowedToDispatchInSystemGroup() const;
+  /**
+   * Whether the event should be blocked for fingerprinting resistance.
+   */
+  bool IsBlockedForFingerprintingResistance() const;
+  /**
+   * Whether the event handler can flush pending notifications or not.
+   */
+  bool AllowFlushingPendingNotifications() const;
+  /**
+   * Initialize mComposed
+   */
+  void SetDefaultComposed() {
+    switch (mClass) {
+      case eClipboardEventClass:
+        mFlags.mComposed = true;
+        break;
+      case eCompositionEventClass:
+        mFlags.mComposed =
+            mMessage == eCompositionStart || mMessage == eCompositionUpdate ||
+            mMessage == eCompositionChange || mMessage == eCompositionEnd;
+        break;
+      case eDragEventClass:
+        // All drag & drop events are composed
+        mFlags.mComposed = mMessage == eDrag || mMessage == eDragEnd ||
+                           mMessage == eDragEnter || mMessage == eDragExit ||
+                           mMessage == eDragLeave || mMessage == eDragOver ||
+                           mMessage == eDragStart || mMessage == eDrop;
+        break;
+      case eEditorInputEventClass:
+        mFlags.mComposed =
+            mMessage == eEditorInput || mMessage == eEditorBeforeInput;
+        break;
+      case eFocusEventClass:
+        mFlags.mComposed = mMessage == eBlur || mMessage == eFocus ||
+                           mMessage == eFocusOut || mMessage == eFocusIn;
+        break;
+      case eKeyboardEventClass:
+        mFlags.mComposed =
+            mMessage == eKeyDown || mMessage == eKeyUp || mMessage == eKeyPress;
+        break;
+      case eMouseEventClass:
+        mFlags.mComposed =
+            mMessage == eMouseClick || mMessage == eMouseDoubleClick ||
+            mMessage == eMouseAuxClick || mMessage == eMouseDown ||
+            mMessage == eMouseUp || mMessage == eMouseOver ||
+            mMessage == eMouseOut || mMessage == eMouseMove ||
+            mMessage == eContextMenu || mMessage == eXULPopupShowing ||
+            mMessage == eXULPopupHiding || mMessage == eXULPopupShown ||
+            mMessage == eXULPopupHidden;
+        break;
+      case ePointerEventClass:
+        // All pointer events are composed
+        mFlags.mComposed =
+            mMessage == ePointerDown || mMessage == ePointerMove ||
+            mMessage == ePointerUp || mMessage == ePointerCancel ||
+            mMessage == ePointerOver || mMessage == ePointerOut ||
+            mMessage == ePointerGotCapture || mMessage == ePointerLostCapture;
+        break;
+      case eTouchEventClass:
+        // All touch events are composed
+        mFlags.mComposed = mMessage == eTouchStart || mMessage == eTouchEnd ||
+                           mMessage == eTouchMove || mMessage == eTouchCancel;
+        break;
+      case eUIEventClass:
+        mFlags.mComposed = mMessage == eLegacyDOMFocusIn ||
+                           mMessage == eLegacyDOMFocusOut ||
+                           mMessage == eLegacyDOMActivate;
+        break;
+      case eWheelEventClass:
+        // All wheel events are composed
+        mFlags.mComposed = mMessage == eWheel;
+        break;
+      case eMouseScrollEventClass:
+        // Legacy mouse scroll events are composed too, for consistency with
+        // wheel.
+        mFlags.mComposed = mMessage == eLegacyMouseLineOrPageScroll ||
+                           mMessage == eLegacyMousePixelScroll;
+        break;
+      default:
+        mFlags.mComposed = false;
+        break;
+    }
+  }
+
+  void SetComposed(const nsAString& aEventTypeArg) {
+    mFlags.mComposed =  // composition events
+        aEventTypeArg.EqualsLiteral("compositionstart") ||
+        aEventTypeArg.EqualsLiteral("compositionupdate") ||
+        aEventTypeArg.EqualsLiteral("compositionend") ||
+        aEventTypeArg.EqualsLiteral("text") ||
+        // drag and drop events
+        aEventTypeArg.EqualsLiteral("dragstart") ||
+        aEventTypeArg.EqualsLiteral("drag") ||
+        aEventTypeArg.EqualsLiteral("dragenter") ||
+        aEventTypeArg.EqualsLiteral("dragexit") ||
+        aEventTypeArg.EqualsLiteral("dragleave") ||
+        aEventTypeArg.EqualsLiteral("dragover") ||
+        aEventTypeArg.EqualsLiteral("drop") ||
+        aEventTypeArg.EqualsLiteral("dropend") ||
+        // editor input events
+        aEventTypeArg.EqualsLiteral("input") ||
+        aEventTypeArg.EqualsLiteral("beforeinput") ||
+        // focus events
+        aEventTypeArg.EqualsLiteral("blur") ||
+        aEventTypeArg.EqualsLiteral("focus") ||
+        aEventTypeArg.EqualsLiteral("focusin") ||
+        aEventTypeArg.EqualsLiteral("focusout") ||
+        // keyboard events
+        aEventTypeArg.EqualsLiteral("keydown") ||
+        aEventTypeArg.EqualsLiteral("keyup") ||
+        aEventTypeArg.EqualsLiteral("keypress") ||
+        // mouse events
+        aEventTypeArg.EqualsLiteral("click") ||
+        aEventTypeArg.EqualsLiteral("dblclick") ||
+        aEventTypeArg.EqualsLiteral("mousedown") ||
+        aEventTypeArg.EqualsLiteral("mouseup") ||
+        aEventTypeArg.EqualsLiteral("mouseenter") ||
+        aEventTypeArg.EqualsLiteral("mouseleave") ||
+        aEventTypeArg.EqualsLiteral("mouseover") ||
+        aEventTypeArg.EqualsLiteral("mouseout") ||
+        aEventTypeArg.EqualsLiteral("mousemove") ||
+        aEventTypeArg.EqualsLiteral("contextmenu") ||
+        // pointer events
+        aEventTypeArg.EqualsLiteral("pointerdown") ||
+        aEventTypeArg.EqualsLiteral("pointermove") ||
+        aEventTypeArg.EqualsLiteral("pointerup") ||
+        aEventTypeArg.EqualsLiteral("pointercancel") ||
+        aEventTypeArg.EqualsLiteral("pointerover") ||
+        aEventTypeArg.EqualsLiteral("pointerout") ||
+        aEventTypeArg.EqualsLiteral("pointerenter") ||
+        aEventTypeArg.EqualsLiteral("pointerleave") ||
+        aEventTypeArg.EqualsLiteral("gotpointercapture") ||
+        aEventTypeArg.EqualsLiteral("lostpointercapture") ||
+        // touch events
+        aEventTypeArg.EqualsLiteral("touchstart") ||
+        aEventTypeArg.EqualsLiteral("touchend") ||
+        aEventTypeArg.EqualsLiteral("touchmove") ||
+        aEventTypeArg.EqualsLiteral("touchcancel") ||
+        // UI legacy events
+        aEventTypeArg.EqualsLiteral("DOMFocusIn") ||
+        aEventTypeArg.EqualsLiteral("DOMFocusOut") ||
+        aEventTypeArg.EqualsLiteral("DOMActivate") ||
+        // wheel events
+        aEventTypeArg.EqualsLiteral("wheel");
+  }
+
+  void SetComposed(bool aComposed) { mFlags.mComposed = aComposed; }
+
+  void SetDefaultComposedInNativeAnonymousContent() {
+    // For compatibility concerns, we set mComposedInNativeAnonymousContent to
+    // false for those events we want to stop propagation.
+    //
+    // nsVideoFrame may create anonymous image element which fires eLoad,
+    // eLoadStart, eLoadEnd, eLoadError. We don't want these events cross
+    // the boundary of NAC
+    mFlags.mComposedInNativeAnonymousContent =
+        mMessage != eLoad && mMessage != eLoadStart && mMessage != eLoadEnd &&
+        mMessage != eLoadError;
+  }
+
+  bool IsUserAction() const;
+};
+
+/******************************************************************************
+ * mozilla::WidgetGUIEvent
+ ******************************************************************************/
+
+class WidgetGUIEvent : public WidgetEvent {
+ protected:
+  WidgetGUIEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
+                 EventClassID aEventClassID,
+                 const WidgetEventTime* aTime = nullptr)
+      : WidgetEvent(aIsTrusted, aMessage, aEventClassID, aTime),
+        mWidget(aWidget) {}
+
+  WidgetGUIEvent() = default;
+
+ public:
+  virtual WidgetGUIEvent* AsGUIEvent() override { return this; }
+
+  WidgetGUIEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
+                 const WidgetEventTime* aTime = nullptr)
+      : WidgetEvent(aIsTrusted, aMessage, eGUIEventClass, aTime),
+        mWidget(aWidget) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eGUIEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetGUIEvent* result = new WidgetGUIEvent(false, mMessage, nullptr, this);
+    result->AssignGUIEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  // Originator of the event
+  nsCOMPtr<nsIWidget> mWidget;
+
+  void AssignGUIEventData(const WidgetGUIEvent& aEvent, bool aCopyTargets) {
+    AssignEventData(aEvent, aCopyTargets);
+    // widget should be initialized with the constructor.
+  }
+};
+
+/******************************************************************************
+ * mozilla::Modifier
+ *
+ * All modifier keys should be defined here.  This is used for managing
+ * modifier states for DOM Level 3 or later.
+ ******************************************************************************/
+
+enum Modifier {
+  MODIFIER_NONE = 0x0000,
+  MODIFIER_ALT = 0x0001,
+  MODIFIER_ALTGRAPH = 0x0002,
+  MODIFIER_CAPSLOCK = 0x0004,
+  MODIFIER_CONTROL = 0x0008,
+  MODIFIER_FN = 0x0010,
+  MODIFIER_FNLOCK = 0x0020,
+  MODIFIER_META = 0x0040,
+  MODIFIER_NUMLOCK = 0x0080,
+  MODIFIER_SCROLLLOCK = 0x0100,
+  MODIFIER_SHIFT = 0x0200,
+  MODIFIER_SYMBOL = 0x0400,
+  MODIFIER_SYMBOLLOCK = 0x0800,
+};
+
+/******************************************************************************
+ * Modifier key names.
+ ******************************************************************************/
+
+#define NS_DOM_KEYNAME_ALT "Alt"
+#define NS_DOM_KEYNAME_ALTGRAPH "AltGraph"
+#define NS_DOM_KEYNAME_CAPSLOCK "CapsLock"
+#define NS_DOM_KEYNAME_CONTROL "Control"
+#define NS_DOM_KEYNAME_FN "Fn"
+#define NS_DOM_KEYNAME_FNLOCK "FnLock"
+#define NS_DOM_KEYNAME_META "Meta"
+#define NS_DOM_KEYNAME_NUMLOCK "NumLock"
+#define NS_DOM_KEYNAME_SCROLLLOCK "ScrollLock"
+#define NS_DOM_KEYNAME_SHIFT "Shift"
+#define NS_DOM_KEYNAME_SYMBOL "Symbol"
+#define NS_DOM_KEYNAME_SYMBOLLOCK "SymbolLock"
+#define NS_DOM_KEYNAME_OS "OS"
+
+/******************************************************************************
+ * mozilla::Modifiers
+ ******************************************************************************/
+
+typedef uint16_t Modifiers;
+
+class MOZ_STACK_CLASS GetModifiersName final : public nsAutoCString {
+ public:
+  explicit GetModifiersName(Modifiers aModifiers) {
+    if (aModifiers & MODIFIER_ALT) {
+      AssignLiteral(NS_DOM_KEYNAME_ALT);
+    }
+    if (aModifiers & MODIFIER_ALTGRAPH) {
+      MaybeAppendSeparator();
+      AppendLiteral(NS_DOM_KEYNAME_ALTGRAPH);
+    }
+    if (aModifiers & MODIFIER_CAPSLOCK) {
+      MaybeAppendSeparator();
+      AppendLiteral(NS_DOM_KEYNAME_CAPSLOCK);
+    }
+    if (aModifiers & MODIFIER_CONTROL) {
+      MaybeAppendSeparator();
+      AppendLiteral(NS_DOM_KEYNAME_CONTROL);
+    }
+    if (aModifiers & MODIFIER_FN) {
+      MaybeAppendSeparator();
+      AppendLiteral(NS_DOM_KEYNAME_FN);
+    }
+    if (aModifiers & MODIFIER_FNLOCK) {
+      MaybeAppendSeparator();
+      AppendLiteral(NS_DOM_KEYNAME_FNLOCK);
+    }
+    if (aModifiers & MODIFIER_META) {
+      MaybeAppendSeparator();
+      AppendLiteral(NS_DOM_KEYNAME_META);
+    }
+    if (aModifiers & MODIFIER_NUMLOCK) {
+      MaybeAppendSeparator();
+      AppendLiteral(NS_DOM_KEYNAME_NUMLOCK);
+    }
+    if (aModifiers & MODIFIER_SCROLLLOCK) {
+      MaybeAppendSeparator();
+      AppendLiteral(NS_DOM_KEYNAME_SCROLLLOCK);
+    }
+    if (aModifiers & MODIFIER_SHIFT) {
+      MaybeAppendSeparator();
+      AppendLiteral(NS_DOM_KEYNAME_SHIFT);
+    }
+    if (aModifiers & MODIFIER_SYMBOL) {
+      MaybeAppendSeparator();
+      AppendLiteral(NS_DOM_KEYNAME_SYMBOL);
+    }
+    if (aModifiers & MODIFIER_SYMBOLLOCK) {
+      MaybeAppendSeparator();
+      AppendLiteral(NS_DOM_KEYNAME_SYMBOLLOCK);
+    }
+    if (IsEmpty()) {
+      AssignLiteral("none");
+    }
+  }
+
+ private:
+  void MaybeAppendSeparator() {
+    if (!IsEmpty()) {
+      AppendLiteral(" | ");
+    }
+  }
+};
+
+/******************************************************************************
+ * mozilla::WidgetInputEvent
+ ******************************************************************************/
+
+class WidgetInputEvent : public WidgetGUIEvent {
+ protected:
+  WidgetInputEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
+                   EventClassID aEventClassID,
+                   const WidgetEventTime* aTime = nullptr)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, aEventClassID, aTime),
+        mModifiers(0) {}
+
+  WidgetInputEvent() : mModifiers(0) {}
+
+ public:
+  virtual WidgetInputEvent* AsInputEvent() override { return this; }
+
+  WidgetInputEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
+                   const WidgetEventTime* aTime = nullptr)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eInputEventClass, aTime),
+        mModifiers(0) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eInputEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetInputEvent* result =
+        new WidgetInputEvent(false, mMessage, nullptr, this);
+    result->AssignInputEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  /**
+   * Returns a modifier of "Accel" virtual modifier which is used for shortcut
+   * key.
+   */
+  static Modifier AccelModifier();
+
+  /**
+   * GetModifier() returns a modifier flag which is activated by aDOMKeyName.
+   */
+  static Modifier GetModifier(const nsAString& aDOMKeyName);
+
+  // true indicates the accel key on the environment is down
+  bool IsAccel() const { return ((mModifiers & AccelModifier()) != 0); }
+
+  // true indicates the shift key is down
+  bool IsShift() const { return ((mModifiers & MODIFIER_SHIFT) != 0); }
+  // true indicates the control key is down
+  bool IsControl() const { return ((mModifiers & MODIFIER_CONTROL) != 0); }
+  // true indicates the alt key is down
+  bool IsAlt() const { return ((mModifiers & MODIFIER_ALT) != 0); }
+  // true indicates the meta key is down (Command key on macOS, Windows logo key
+  // on Windows, Super/Hyper key on Linux, Meta key on Android).
+  bool IsMeta() const { return ((mModifiers & MODIFIER_META) != 0); }
+  // true indicates the alt graph key is down
+  // NOTE: on Mac, the option key press causes both IsAlt() and IsAltGrpah()
+  //       return true.
+  bool IsAltGraph() const { return ((mModifiers & MODIFIER_ALTGRAPH) != 0); }
+  // true indicates the CapLock LED is turn on.
+  bool IsCapsLocked() const { return ((mModifiers & MODIFIER_CAPSLOCK) != 0); }
+  // true indicates the NumLock LED is turn on.
+  bool IsNumLocked() const { return ((mModifiers & MODIFIER_NUMLOCK) != 0); }
+  // true indicates the ScrollLock LED is turn on.
+  bool IsScrollLocked() const {
+    return ((mModifiers & MODIFIER_SCROLLLOCK) != 0);
+  }
+
+  // true indicates the Fn key is down, but this is not supported by native
+  // key event on any platform.
+  bool IsFn() const { return ((mModifiers & MODIFIER_FN) != 0); }
+  // true indicates the FnLock LED is turn on, but we don't know such
+  // keyboards nor platforms.
+  bool IsFnLocked() const { return ((mModifiers & MODIFIER_FNLOCK) != 0); }
+  // true indicates the Symbol is down, but this is not supported by native
+  // key event on any platforms.
+  bool IsSymbol() const { return ((mModifiers & MODIFIER_SYMBOL) != 0); }
+  // true indicates the SymbolLock LED is turn on, but we don't know such
+  // keyboards nor platforms.
+  bool IsSymbolLocked() const {
+    return ((mModifiers & MODIFIER_SYMBOLLOCK) != 0);
+  }
+
+  void InitBasicModifiers(bool aCtrlKey, bool aAltKey, bool aShiftKey,
+                          bool aMetaKey) {
+    mModifiers = 0;
+    if (aCtrlKey) {
+      mModifiers |= MODIFIER_CONTROL;
+    }
+    if (aAltKey) {
+      mModifiers |= MODIFIER_ALT;
+    }
+    if (aShiftKey) {
+      mModifiers |= MODIFIER_SHIFT;
+    }
+    if (aMetaKey) {
+      mModifiers |= MODIFIER_META;
+    }
+  }
+
+  Modifiers mModifiers;
+
+  void AssignInputEventData(const WidgetInputEvent& aEvent, bool aCopyTargets) {
+    AssignGUIEventData(aEvent, aCopyTargets);
+
+    mModifiers = aEvent.mModifiers;
+  }
+};
+
+/******************************************************************************
+ * mozilla::InternalUIEvent
+ *
+ * XXX Why this inherits WidgetGUIEvent rather than WidgetEvent?
+ ******************************************************************************/
+
+class InternalUIEvent : public WidgetGUIEvent {
+ protected:
+  InternalUIEvent() : mDetail(0), mCausedByUntrustedEvent(false) {}
+
+  InternalUIEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
+                  EventClassID aEventClassID,
+                  const WidgetEventTime* aTime = nullptr)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, aEventClassID, aTime),
+        mDetail(0),
+        mCausedByUntrustedEvent(false) {}
+
+  InternalUIEvent(bool aIsTrusted, EventMessage aMessage,
+                  EventClassID aEventClassID,
+                  const WidgetEventTime* aTime = nullptr)
+      : WidgetGUIEvent(aIsTrusted, aMessage, nullptr, aEventClassID, aTime),
+        mDetail(0),
+        mCausedByUntrustedEvent(false) {}
+
+ public:
+  virtual InternalUIEvent* AsUIEvent() override { return this; }
+
+  /**
+   * If the UIEvent is caused by another event (e.g., click event),
+   * aEventCausesThisEvent should be the event.  If there is no such event,
+   * this should be nullptr.
+   */
+  InternalUIEvent(bool aIsTrusted, EventMessage aMessage,
+                  const WidgetEvent* aEventCausesThisEvent,
+                  const WidgetEventTime* aTime = nullptr)
+      : WidgetGUIEvent(aIsTrusted, aMessage, nullptr, eUIEventClass, aTime),
+        mDetail(0),
+        mCausedByUntrustedEvent(aEventCausesThisEvent &&
+                                !aEventCausesThisEvent->IsTrusted()) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eUIEventClass,
+               "Duplicate() must be overridden by sub class");
+    InternalUIEvent* result =
+        new InternalUIEvent(false, mMessage, nullptr, this);
+    result->AssignUIEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  int32_t mDetail;
+  // mCausedByUntrustedEvent is true if the event is caused by untrusted event.
+  bool mCausedByUntrustedEvent;
+
+  // If you check the event is a trusted event and NOT caused by an untrusted
+  // event, IsTrustable() returns what you expected.
+  bool IsTrustable() const { return IsTrusted() && !mCausedByUntrustedEvent; }
+
+  void AssignUIEventData(const InternalUIEvent& aEvent, bool aCopyTargets) {
+    AssignGUIEventData(aEvent, aCopyTargets);
+
+    mDetail = aEvent.mDetail;
+    mCausedByUntrustedEvent = aEvent.mCausedByUntrustedEvent;
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_BasicEvents_h__
diff --git a/widget/ClipboardReadRequestChild.h b/widget/ClipboardReadRequestChild.h
new file mode 100644
index 0000000000..81d82e6296
--- /dev/null
+++ b/widget/ClipboardReadRequestChild.h
@@ -0,0 +1,34 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ClipboardReadRequestChild_h
+#define mozilla_ClipboardReadRequestChild_h
+
+#include "mozilla/PClipboardReadRequestChild.h"
+
+class nsITransferable;
+
+namespace mozilla {
+
+class ClipboardReadRequestChild final : public PClipboardReadRequestChild {
+ public:
+  explicit ClipboardReadRequestChild(const nsTArray<nsCString>& aFlavorList) {
+    mFlavorList.AppendElements(aFlavorList);
+  }
+
+  NS_INLINE_DECL_REFCOUNTING(ClipboardReadRequestChild)
+
+  const nsTArray<nsCString>& FlavorList() const { return mFlavorList; }
+
+ protected:
+  virtual ~ClipboardReadRequestChild() = default;
+
+ private:
+  nsTArray<nsCString> mFlavorList;
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_ClipboardReadRequestChild_h
diff --git a/widget/ClipboardReadRequestParent.cpp b/widget/ClipboardReadRequestParent.cpp
new file mode 100644
index 0000000000..3f045a800a
--- /dev/null
+++ b/widget/ClipboardReadRequestParent.cpp
@@ -0,0 +1,115 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ClipboardReadRequestParent.h"
+
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/net/CookieJarSettings.h"
+#include "nsComponentManagerUtils.h"
+#include "nsIClipboard.h"
+#include "nsITransferable.h"
+#include "nsWidgetsCID.h"
+
+using mozilla::dom::ContentParent;
+using mozilla::ipc::IPCResult;
+
+namespace mozilla {
+
+namespace {
+
+class ClipboardGetDataCallback final : public nsIAsyncClipboardRequestCallback {
+ public:
+  explicit ClipboardGetDataCallback(std::function<void(nsresult)>&& aCallback)
+      : mCallback(std::move(aCallback)) {}
+
+  // This object will never be held by a cycle-collected object, so it doesn't
+  // need to be cycle-collected despite holding alive cycle-collected objects.
+  NS_DECL_ISUPPORTS
+
+  // nsIAsyncClipboardRequestCallback
+  NS_IMETHOD OnComplete(nsresult aResult) override {
+    mCallback(aResult);
+    return NS_OK;
+  }
+
+ protected:
+  ~ClipboardGetDataCallback() = default;
+
+  std::function<void(nsresult)> mCallback;
+};
+
+NS_IMPL_ISUPPORTS(ClipboardGetDataCallback, nsIAsyncClipboardRequestCallback)
+
+static Result<nsCOMPtr<nsITransferable>, nsresult> CreateTransferable(
+    const nsTArray<nsCString>& aTypes) {
+  nsresult rv;
+  nsCOMPtr<nsITransferable> trans =
+      do_CreateInstance("@mozilla.org/widget/transferable;1", &rv);
+  if (NS_FAILED(rv)) {
+    return Err(rv);
+  }
+
+  MOZ_TRY(trans->Init(nullptr));
+  // The private flag is only used to prevent the data from being cached to the
+  // disk. The flag is not exported to the IPCDataTransfer object.
+  // The flag is set because we are not sure whether the clipboard data is used
+  // in a private browsing context. The transferable is only used in this scope,
+  // so the cache would not reduce memory consumption anyway.
+  trans->SetIsPrivateData(true);
+  // Fill out flavors for transferable
+  for (uint32_t t = 0; t < aTypes.Length(); t++) {
+    MOZ_TRY(trans->AddDataFlavor(aTypes[t].get()));
+  }
+
+  return std::move(trans);
+}
+
+}  // namespace
+
+IPCResult ClipboardReadRequestParent::RecvGetData(
+    const nsTArray<nsCString>& aFlavors, GetDataResolver&& aResolver) {
+  bool valid = false;
+  if (NS_FAILED(mAsyncGetClipboardData->GetValid(&valid)) || !valid) {
+    Unused << PClipboardReadRequestParent::Send__delete__(this);
+    aResolver(NS_ERROR_FAILURE);
+    return IPC_OK();
+  }
+
+  // Create transferable
+  auto result = CreateTransferable(aFlavors);
+  if (result.isErr()) {
+    aResolver(result.unwrapErr());
+    return IPC_OK();
+  }
+
+  nsCOMPtr<nsITransferable> trans = result.unwrap();
+  RefPtr<ClipboardGetDataCallback> callback =
+      MakeRefPtr<ClipboardGetDataCallback>([self = RefPtr{this},
+                                            resolver = std::move(aResolver),
+                                            trans,
+                                            manager = mManager](nsresult aRv) {
+        if (NS_FAILED(aRv)) {
+          bool valid = false;
+          if (NS_FAILED(self->mAsyncGetClipboardData->GetValid(&valid)) ||
+              !valid) {
+            Unused << PClipboardReadRequestParent::Send__delete__(self);
+          }
+          resolver(aRv);
+          return;
+        }
+
+        dom::IPCTransferableData ipcTransferableData;
+        nsContentUtils::TransferableToIPCTransferableData(
+            trans, &ipcTransferableData, false /* aInSyncMessage */, manager);
+        resolver(std::move(ipcTransferableData));
+      });
+  nsresult rv = mAsyncGetClipboardData->GetData(trans, callback);
+  if (NS_FAILED(rv)) {
+    callback->OnComplete(rv);
+  }
+  return IPC_OK();
+}
+
+}  // namespace mozilla
diff --git a/widget/ClipboardReadRequestParent.h b/widget/ClipboardReadRequestParent.h
new file mode 100644
index 0000000000..cd51c4e300
--- /dev/null
+++ b/widget/ClipboardReadRequestParent.h
@@ -0,0 +1,39 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ClipboardReadRequestParent_h
+#define mozilla_ClipboardReadRequestParent_h
+
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/PClipboardReadRequestParent.h"
+#include "nsIClipboard.h"
+
+namespace mozilla {
+
+class ClipboardReadRequestParent final : public PClipboardReadRequestParent {
+  using IPCResult = mozilla::ipc::IPCResult;
+  using ContentParent = mozilla::dom::ContentParent;
+
+ public:
+  ClipboardReadRequestParent(ContentParent* aManager,
+                             nsIAsyncGetClipboardData* aAsyncGetClipboardData)
+      : mManager(aManager), mAsyncGetClipboardData(aAsyncGetClipboardData) {}
+
+  NS_INLINE_DECL_REFCOUNTING(ClipboardReadRequestParent, override)
+
+  // PClipboardReadRequestParent
+  IPCResult RecvGetData(const nsTArray<nsCString>& aFlavors,
+                        GetDataResolver&& aResolver);
+
+ private:
+  ~ClipboardReadRequestParent() = default;
+
+  RefPtr<ContentParent> mManager;
+  nsCOMPtr<nsIAsyncGetClipboardData> mAsyncGetClipboardData;
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_ClipboardReadRequestParent_h
diff --git a/widget/ClipboardWriteRequestChild.cpp b/widget/ClipboardWriteRequestChild.cpp
new file mode 100644
index 0000000000..0c42f7380d
--- /dev/null
+++ b/widget/ClipboardWriteRequestChild.cpp
@@ -0,0 +1,73 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ClipboardWriteRequestChild.h"
+
+#if defined(ACCESSIBILITY) && defined(XP_WIN)
+#  include "mozilla/a11y/Compatibility.h"
+#endif
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/net/CookieJarSettings.h"
+#include "nsITransferable.h"
+
+namespace mozilla {
+
+NS_IMPL_ISUPPORTS(ClipboardWriteRequestChild, nsIAsyncSetClipboardData)
+
+NS_IMETHODIMP
+ClipboardWriteRequestChild::SetData(nsITransferable* aTransferable,
+                                    nsIClipboardOwner* aOwner) {
+  MOZ_ASSERT(aTransferable);
+  // Callback should be notified if actor is destroyed.
+  MOZ_ASSERT_IF(!CanSend(), !mIsValid && !mCallback);
+
+  if (!mIsValid) {
+    return NS_ERROR_FAILURE;
+  }
+
+#if defined(ACCESSIBILITY) && defined(XP_WIN)
+  a11y::Compatibility::SuppressA11yForClipboardCopy();
+#endif
+
+  mIsValid = false;
+  IPCTransferable ipcTransferable;
+  nsContentUtils::TransferableToIPCTransferable(aTransferable, &ipcTransferable,
+                                                false, nullptr);
+  SendSetData(std::move(ipcTransferable));
+  return NS_OK;
+}
+
+NS_IMETHODIMP ClipboardWriteRequestChild::Abort(nsresult aReason) {
+  // Callback should be notified if actor is destroyed.
+  MOZ_ASSERT_IF(!CanSend(), !mIsValid && !mCallback);
+
+  if (!mIsValid || !NS_FAILED(aReason)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Need to notify callback first to propagate reason properly.
+  MaybeNotifyCallback(aReason);
+  Unused << PClipboardWriteRequestChild::Send__delete__(this, aReason);
+  return NS_OK;
+}
+
+ipc::IPCResult ClipboardWriteRequestChild::Recv__delete__(nsresult aResult) {
+  MaybeNotifyCallback(aResult);
+  return IPC_OK();
+}
+
+void ClipboardWriteRequestChild::ActorDestroy(ActorDestroyReason aReason) {
+  MaybeNotifyCallback(NS_ERROR_ABORT);
+}
+
+void ClipboardWriteRequestChild::MaybeNotifyCallback(nsresult aResult) {
+  mIsValid = false;
+  if (nsCOMPtr<nsIAsyncClipboardRequestCallback> callback =
+          mCallback.forget()) {
+    callback->OnComplete(aResult);
+  }
+}
+
+}  // namespace mozilla
diff --git a/widget/ClipboardWriteRequestChild.h b/widget/ClipboardWriteRequestChild.h
new file mode 100644
index 0000000000..078cfa07de
--- /dev/null
+++ b/widget/ClipboardWriteRequestChild.h
@@ -0,0 +1,40 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ClipboardWriteRequestChild_h
+#define mozilla_ClipboardWriteRequestChild_h
+
+#include "mozilla/PClipboardWriteRequestChild.h"
+#include "nsIClipboard.h"
+
+class nsITransferable;
+
+namespace mozilla {
+
+class ClipboardWriteRequestChild : public PClipboardWriteRequestChild,
+                                   public nsIAsyncSetClipboardData {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIASYNCSETCLIPBOARDDATA
+
+  explicit ClipboardWriteRequestChild(
+      nsIAsyncClipboardRequestCallback* aCallback)
+      : mCallback(aCallback) {}
+
+  ipc::IPCResult Recv__delete__(nsresult aResult);
+  void ActorDestroy(ActorDestroyReason aReason) override final;
+
+ protected:
+  virtual ~ClipboardWriteRequestChild() = default;
+
+  void MaybeNotifyCallback(nsresult aResult);
+
+  bool mIsValid = true;
+  nsCOMPtr<nsIAsyncClipboardRequestCallback> mCallback;
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_ClipboardWriteRequestChild_h
diff --git a/widget/ClipboardWriteRequestParent.cpp b/widget/ClipboardWriteRequestParent.cpp
new file mode 100644
index 0000000000..751befbe05
--- /dev/null
+++ b/widget/ClipboardWriteRequestParent.cpp
@@ -0,0 +1,113 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ClipboardWriteRequestParent.h"
+
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/net/CookieJarSettings.h"
+#include "nsComponentManagerUtils.h"
+#include "nsIClipboard.h"
+#include "nsITransferable.h"
+#include "nsWidgetsCID.h"
+
+static NS_DEFINE_CID(kCClipboardCID, NS_CLIPBOARD_CID);
+
+using mozilla::dom::ContentParent;
+using mozilla::ipc::IPCResult;
+
+namespace mozilla {
+
+NS_IMPL_ISUPPORTS(ClipboardWriteRequestParent, nsIAsyncClipboardRequestCallback)
+
+ClipboardWriteRequestParent::ClipboardWriteRequestParent(
+    ContentParent* aManager)
+    : mManager(aManager) {}
+
+ClipboardWriteRequestParent::~ClipboardWriteRequestParent() = default;
+
+nsresult ClipboardWriteRequestParent::Init(const int32_t& aClipboardType) {
+  nsCOMPtr<nsIClipboard> clipboard(do_GetService(kCClipboardCID));
+  if (!clipboard) {
+    Unused << PClipboardWriteRequestParent::Send__delete__(this,
+                                                           NS_ERROR_FAILURE);
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult rv = clipboard->AsyncSetData(aClipboardType, this,
+                                        getter_AddRefs(mAsyncSetClipboardData));
+  if (NS_FAILED(rv)) {
+    Unused << PClipboardWriteRequestParent::Send__delete__(this, rv);
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP ClipboardWriteRequestParent::OnComplete(nsresult aResult) {
+  nsCOMPtr<nsIAsyncSetClipboardData> clipboardData =
+      std::move(mAsyncSetClipboardData);
+  if (clipboardData) {
+    Unused << PClipboardWriteRequestParent::Send__delete__(this, aResult);
+  }
+  return NS_OK;
+}
+
+IPCResult ClipboardWriteRequestParent::RecvSetData(
+    const IPCTransferable& aTransferable) {
+  if (!mManager->ValidatePrincipal(
+          aTransferable.requestingPrincipal(),
+          {ContentParent::ValidatePrincipalOptions::AllowNullPtr,
+           ContentParent::ValidatePrincipalOptions::AllowExpanded,
+           ContentParent::ValidatePrincipalOptions::AllowSystem})) {
+    ContentParent::LogAndAssertFailedPrincipalValidationInfo(
+        aTransferable.requestingPrincipal(), __func__);
+  }
+
+  if (!mAsyncSetClipboardData) {
+    return IPC_OK();
+  }
+
+  nsresult rv = NS_ERROR_FAILURE;
+  nsCOMPtr<nsITransferable> trans =
+      do_CreateInstance("@mozilla.org/widget/transferable;1", &rv);
+  if (NS_FAILED(rv)) {
+    mAsyncSetClipboardData->Abort(rv);
+    return IPC_OK();
+  }
+
+  trans->Init(nullptr);
+  rv = nsContentUtils::IPCTransferableToTransferable(
+      aTransferable, true /* aAddDataFlavor */, trans,
+      true /* aFilterUnknownFlavors */);
+  if (NS_FAILED(rv)) {
+    mAsyncSetClipboardData->Abort(rv);
+    return IPC_OK();
+  }
+
+  mAsyncSetClipboardData->SetData(trans, nullptr);
+  return IPC_OK();
+}
+
+IPCResult ClipboardWriteRequestParent::Recv__delete__(nsresult aReason) {
+#ifndef FUZZING_SNAPSHOT
+  MOZ_DIAGNOSTIC_ASSERT(NS_FAILED(aReason));
+#endif
+  nsCOMPtr<nsIAsyncSetClipboardData> clipboardData =
+      std::move(mAsyncSetClipboardData);
+  if (clipboardData) {
+    clipboardData->Abort(aReason);
+  }
+  return IPC_OK();
+}
+
+void ClipboardWriteRequestParent::ActorDestroy(ActorDestroyReason aReason) {
+  nsCOMPtr<nsIAsyncSetClipboardData> clipboardData =
+      std::move(mAsyncSetClipboardData);
+  if (clipboardData) {
+    clipboardData->Abort(NS_ERROR_ABORT);
+  }
+}
+
+}  // namespace mozilla
diff --git a/widget/ClipboardWriteRequestParent.h b/widget/ClipboardWriteRequestParent.h
new file mode 100644
index 0000000000..6027661bdb
--- /dev/null
+++ b/widget/ClipboardWriteRequestParent.h
@@ -0,0 +1,46 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ClipboardWriteRequestParent_h
+#define mozilla_ClipboardWriteRequestParent_h
+
+#include "mozilla/PClipboardWriteRequestParent.h"
+#include "nsIClipboard.h"
+
+namespace mozilla {
+
+namespace dom {
+class ContentParent;
+}
+
+class ClipboardWriteRequestParent final
+    : public PClipboardWriteRequestParent,
+      public nsIAsyncClipboardRequestCallback {
+  using IPCResult = mozilla::ipc::IPCResult;
+  using ContentParent = mozilla::dom::ContentParent;
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIASYNCCLIPBOARDREQUESTCALLBACK
+
+  explicit ClipboardWriteRequestParent(ContentParent* aManager);
+
+  nsresult Init(const int32_t& aClipboardType);
+
+  IPCResult RecvSetData(const IPCTransferable& aTransferable);
+  IPCResult Recv__delete__(nsresult aReason);
+
+  void ActorDestroy(ActorDestroyReason aReason) override final;
+
+ private:
+  ~ClipboardWriteRequestParent();
+
+  RefPtr<ContentParent> mManager;
+  nsCOMPtr<nsIAsyncSetClipboardData> mAsyncSetClipboardData;
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_ClipboardWriteRequestParent_h
diff --git a/widget/ColorScheme.h b/widget/ColorScheme.h
new file mode 100644
index 0000000000..5a8b1a6cdd
--- /dev/null
+++ b/widget/ColorScheme.h
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ColorScheme_h
+#define mozilla_ColorScheme_h
+
+#include <cstdint>
+
+namespace mozilla {
+
+// Whether we should use a light or dark appearance.
+enum class ColorScheme : uint8_t { Light, Dark };
+
+// The color-scheme we should get back in case it's not explicit. The "used"
+// mode is the mode that most of layout should use (defaults to light if the
+// page doesn't have a color-scheme property / meta-tag indicating otherwise).
+//
+// The "preferred" mode returns the color-scheme for purposes of
+// prefers-color-scheme propagation (that is, it defaults to the current
+// preferred color-scheme, rather than light).
+enum class ColorSchemeMode : uint8_t {
+  Used,
+  Preferred,
+};
+
+}  // namespace mozilla
+
+#endif
diff --git a/widget/CommandList.h b/widget/CommandList.h
new file mode 100644
index 0000000000..243656bb01
--- /dev/null
+++ b/widget/CommandList.h
@@ -0,0 +1,171 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Define NS_DEFINE_COMMAND(aName, aCommandStr) before including this.
+ * @param aName          The name useful in C++ of the command.
+ * @param aCommandStr    The command string in JS.
+ *
+ * Define NS_DEFINE_COMMAND_WITH_PARAM(aName, aCommandStr, aParam) before
+ * including this.
+ * @param aName          The name useful in C++ of the command.
+ * @param aCommandStr    The command string in JS, but this may be shared with
+ *                       other aName values.  I.e., cannot map aName and
+ *                       aCommandStr 1:1.
+ * @param aParam         Additional param value.  When aCommandStr is executed,
+ *                       this value is also specified.  I.e., aName becomes
+ *                       unique when you look for with both aCommandStr and
+ *                       aParam.
+ *
+ * Define NS_DEFINE_COMMAND_NO_EXEC_COMMAND(aName) before including this.
+ * @param aName          The name useful in C++ of the command.
+ */
+
+// Mapped from commands of some platforms
+NS_DEFINE_COMMAND(BeginLine, cmd_beginLine)
+NS_DEFINE_COMMAND(CharNext, cmd_charNext)
+NS_DEFINE_COMMAND(CharPrevious, cmd_charPrevious)
+NS_DEFINE_COMMAND(Copy, cmd_copy)
+NS_DEFINE_COMMAND(Cut, cmd_cut)
+NS_DEFINE_COMMAND(Delete, cmd_delete)
+NS_DEFINE_COMMAND(DeleteCharBackward, cmd_deleteCharBackward)
+NS_DEFINE_COMMAND(DeleteCharForward, cmd_deleteCharForward)
+NS_DEFINE_COMMAND(DeleteToBeginningOfLine, cmd_deleteToBeginningOfLine)
+NS_DEFINE_COMMAND(DeleteToEndOfLine, cmd_deleteToEndOfLine)
+NS_DEFINE_COMMAND(DeleteWordBackward, cmd_deleteWordBackward)
+NS_DEFINE_COMMAND(DeleteWordForward, cmd_deleteWordForward)
+NS_DEFINE_COMMAND(EndLine, cmd_endLine)
+NS_DEFINE_COMMAND(InsertParagraph, cmd_insertParagraph)
+NS_DEFINE_COMMAND(InsertLineBreak, cmd_insertLineBreak)
+NS_DEFINE_COMMAND(LineNext, cmd_lineNext)
+NS_DEFINE_COMMAND(LinePrevious, cmd_linePrevious)
+NS_DEFINE_COMMAND(MoveBottom, cmd_moveBottom)
+NS_DEFINE_COMMAND(MovePageDown, cmd_movePageDown)
+NS_DEFINE_COMMAND(MovePageUp, cmd_movePageUp)
+NS_DEFINE_COMMAND(MoveTop, cmd_moveTop)
+NS_DEFINE_COMMAND(Paste, cmd_paste)
+NS_DEFINE_COMMAND(ScrollBottom, cmd_scrollBottom)
+NS_DEFINE_COMMAND(ScrollLeft, cmd_scrollLeft)
+NS_DEFINE_COMMAND(ScrollLineDown, cmd_scrollLineDown)
+NS_DEFINE_COMMAND(ScrollLineUp, cmd_scrollLineUp)
+NS_DEFINE_COMMAND(ScrollPageDown, cmd_scrollPageDown)
+NS_DEFINE_COMMAND(ScrollPageUp, cmd_scrollPageUp)
+NS_DEFINE_COMMAND(ScrollRight, cmd_scrollRight)
+NS_DEFINE_COMMAND(ScrollTop, cmd_scrollTop)
+NS_DEFINE_COMMAND(SelectAll, cmd_selectAll)
+NS_DEFINE_COMMAND(SelectBeginLine, cmd_selectBeginLine)
+NS_DEFINE_COMMAND(SelectBottom, cmd_selectBottom)
+NS_DEFINE_COMMAND(SelectCharNext, cmd_selectCharNext)
+NS_DEFINE_COMMAND(SelectCharPrevious, cmd_selectCharPrevious)
+NS_DEFINE_COMMAND(SelectEndLine, cmd_selectEndLine)
+NS_DEFINE_COMMAND(SelectLineNext, cmd_selectLineNext)
+NS_DEFINE_COMMAND(SelectLinePrevious, cmd_selectLinePrevious)
+NS_DEFINE_COMMAND(SelectPageDown, cmd_selectPageDown)
+NS_DEFINE_COMMAND(SelectPageUp, cmd_selectPageUp)
+NS_DEFINE_COMMAND(SelectTop, cmd_selectTop)
+NS_DEFINE_COMMAND(SelectWordNext, cmd_selectWordNext)
+NS_DEFINE_COMMAND(SelectWordPrevious, cmd_selectWordPrevious)
+NS_DEFINE_COMMAND(WordNext, cmd_wordNext)
+NS_DEFINE_COMMAND(WordPrevious, cmd_wordPrevious)
+
+// We don't have corresponding commands for them, but some platforms have them.
+NS_DEFINE_COMMAND_NO_EXEC_COMMAND(CancelOperation)
+NS_DEFINE_COMMAND_NO_EXEC_COMMAND(Complete)
+NS_DEFINE_COMMAND_NO_EXEC_COMMAND(InsertBacktab)
+NS_DEFINE_COMMAND_NO_EXEC_COMMAND(InsertTab)
+
+// Commands mapped from HTMLDocument.execCommand()
+NS_DEFINE_COMMAND(FormatBold, cmd_bold)
+NS_DEFINE_COMMAND(FormatItalic, cmd_italic)
+NS_DEFINE_COMMAND(FormatUnderline, cmd_underline)
+NS_DEFINE_COMMAND(FormatStrikeThrough, cmd_strikethrough)
+NS_DEFINE_COMMAND(FormatSubscript, cmd_subscript)
+NS_DEFINE_COMMAND(FormatSuperscript, cmd_superscript)
+NS_DEFINE_COMMAND(HistoryUndo, cmd_undo)
+NS_DEFINE_COMMAND(HistoryRedo, cmd_redo)
+NS_DEFINE_COMMAND(FormatBlock, cmd_formatBlock)
+NS_DEFINE_COMMAND(FormatIndent, cmd_indent)
+NS_DEFINE_COMMAND(FormatOutdent, cmd_outdent)
+NS_DEFINE_COMMAND_WITH_PARAM(FormatJustifyLeft, cmd_align, left)
+NS_DEFINE_COMMAND_WITH_PARAM(FormatJustifyRight, cmd_align, right)
+NS_DEFINE_COMMAND_WITH_PARAM(FormatJustifyCenter, cmd_align, center)
+NS_DEFINE_COMMAND_WITH_PARAM(FormatJustifyFull, cmd_align, justify)
+NS_DEFINE_COMMAND(FormatBackColor, cmd_highlight)
+NS_DEFINE_COMMAND(FormatFontColor, cmd_fontColor)
+NS_DEFINE_COMMAND(FormatFontName, cmd_fontFace)
+NS_DEFINE_COMMAND(FormatFontSize, cmd_fontSize)
+NS_DEFINE_COMMAND(FormatIncreaseFontSize, cmd_increaseFont)
+NS_DEFINE_COMMAND(FormatDecreaseFontSize, cmd_decreaseFont)
+NS_DEFINE_COMMAND(InsertHorizontalRule, cmd_insertHR)
+NS_DEFINE_COMMAND(InsertLink, cmd_insertLinkNoUI)
+NS_DEFINE_COMMAND(InsertImage, cmd_insertImageNoUI)
+NS_DEFINE_COMMAND(InsertHTML, cmd_insertHTML)
+NS_DEFINE_COMMAND(InsertText, cmd_insertText)
+NS_DEFINE_COMMAND(InsertOrderedList, cmd_ol)
+NS_DEFINE_COMMAND(InsertUnorderedList, cmd_ul)
+NS_DEFINE_COMMAND(FormatRemove, cmd_removeStyles)
+NS_DEFINE_COMMAND(FormatRemoveLink, cmd_removeLinks)
+NS_DEFINE_COMMAND(SetDocumentUseCSS, cmd_setDocumentUseCSS)
+NS_DEFINE_COMMAND(SetDocumentReadOnly, cmd_setDocumentReadOnly)
+NS_DEFINE_COMMAND(SetDocumentInsertBROnEnterKeyPress, cmd_insertBrOnReturn)
+NS_DEFINE_COMMAND(SetDocumentDefaultParagraphSeparator,
+                  cmd_defaultParagraphSeparator)
+NS_DEFINE_COMMAND(ToggleObjectResizers, cmd_enableObjectResizing)
+NS_DEFINE_COMMAND(ToggleInlineTableEditor, cmd_enableInlineTableEditing)
+NS_DEFINE_COMMAND(ToggleAbsolutePositionEditor,
+                  cmd_enableAbsolutePositionEditing)
+NS_DEFINE_COMMAND(EnableCompatibleJoinSplitNodeDirection,
+                  cmd_enableCompatibleJoinSplitNodeDirection)
+
+// Commands not mapped from HTMLDocument.execCommand() but available with
+// command dispatcher and handled in editor.
+NS_DEFINE_COMMAND(CutOrDelete, cmd_cutOrDelete)
+NS_DEFINE_COMMAND(CopyOrDelete, cmd_copyOrDelete)
+NS_DEFINE_COMMAND(EditorObserverDocumentCreated, obs_documentCreated)
+NS_DEFINE_COMMAND(EditorObserverDocumentLocationChanged,
+                  obs_documentLocationChanged)
+NS_DEFINE_COMMAND(EditorObserverDocumentWillBeDestroyed,
+                  obs_documentWillBeDestroyed)
+NS_DEFINE_COMMAND(FormatAbbreviation, cmd_abbr)
+NS_DEFINE_COMMAND(FormatAbsolutePosition, cmd_absPos)
+NS_DEFINE_COMMAND(FormatAcronym, cmd_acronym)
+NS_DEFINE_COMMAND(FormatCitation, cmd_cite)
+NS_DEFINE_COMMAND(FormatCode, cmd_code)
+NS_DEFINE_COMMAND(FormatDecreaseZIndex, cmd_decreaseZIndex)
+NS_DEFINE_COMMAND(FormatDocumentBackgroundColor, cmd_backgroundColor)
+NS_DEFINE_COMMAND(FormatEmphasis, cmd_em)
+NS_DEFINE_COMMAND(FormatIncreaseZIndex, cmd_increaseZIndex)
+NS_DEFINE_COMMAND(FormatJustify, cmd_align)  // Only for getting enabled/state
+NS_DEFINE_COMMAND(FormatJustifyNone, cmd_align)  // with empty string or params
+NS_DEFINE_COMMAND(FormatNoBreak, cmd_nobreak)
+NS_DEFINE_COMMAND(FormatRemoveList, cmd_removeList)
+NS_DEFINE_COMMAND(FormatSample, cmd_samp)
+NS_DEFINE_COMMAND(FormatSetBlockTextDirection, cmd_switchTextDirection)
+NS_DEFINE_COMMAND(FormatStrong, cmd_strong)
+NS_DEFINE_COMMAND(FormatTeletypeText, cmd_tt)
+NS_DEFINE_COMMAND(FormatVariable, cmd_var)
+NS_DEFINE_COMMAND(InsertDefinitionDetails, cmd_dd)
+NS_DEFINE_COMMAND(InsertDefinitionTerm, cmd_dt)
+NS_DEFINE_COMMAND(MoveDown, cmd_moveDown)
+NS_DEFINE_COMMAND(MoveDown2, cmd_moveDown2)
+NS_DEFINE_COMMAND(MoveLeft, cmd_moveLeft)
+NS_DEFINE_COMMAND(MoveLeft2, cmd_moveLeft2)
+NS_DEFINE_COMMAND(MoveRight, cmd_moveRight)
+NS_DEFINE_COMMAND(MoveRight2, cmd_moveRight2)
+NS_DEFINE_COMMAND(MoveUp, cmd_moveUp)
+NS_DEFINE_COMMAND(MoveUp2, cmd_moveUp2)
+NS_DEFINE_COMMAND(ParagraphState, cmd_paragraphState)
+NS_DEFINE_COMMAND(PasteAsQuotation, cmd_pasteQuote)
+NS_DEFINE_COMMAND(PasteTransferable, cmd_pasteTransferable)
+NS_DEFINE_COMMAND(PasteWithoutFormat, cmd_pasteNoFormatting)
+NS_DEFINE_COMMAND(SelectDown, cmd_selectDown)
+NS_DEFINE_COMMAND(SelectDown2, cmd_selectDown2)
+NS_DEFINE_COMMAND(SelectLeft, cmd_selectLeft)
+NS_DEFINE_COMMAND(SelectLeft2, cmd_selectLeft2)
+NS_DEFINE_COMMAND(SelectRight, cmd_selectRight)
+NS_DEFINE_COMMAND(SelectRight2, cmd_selectRight2)
+NS_DEFINE_COMMAND(SelectUp, cmd_selectUp)
+NS_DEFINE_COMMAND(SelectUp2, cmd_selectUp2)
+NS_DEFINE_COMMAND(SetDocumentModified, cmd_setDocumentModified)
diff --git a/widget/CompositorWidget.cpp b/widget/CompositorWidget.cpp
new file mode 100644
index 0000000000..6eddecff4a
--- /dev/null
+++ b/widget/CompositorWidget.cpp
@@ -0,0 +1,78 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CompositorWidget.h"
+#include "GLConsts.h"
+#include "nsBaseWidget.h"
+#include "VsyncDispatcher.h"
+
+namespace mozilla {
+namespace widget {
+
+CompositorWidget::CompositorWidget(const layers::CompositorOptions& aOptions)
+    : mOptions(aOptions) {}
+
+CompositorWidget::~CompositorWidget() = default;
+
+already_AddRefed<gfx::DrawTarget> CompositorWidget::StartRemoteDrawing() {
+  return nullptr;
+}
+
+void CompositorWidget::CleanupRemoteDrawing() { mLastBackBuffer = nullptr; }
+
+already_AddRefed<gfx::DrawTarget> CompositorWidget::GetBackBufferDrawTarget(
+    gfx::DrawTarget* aScreenTarget, const gfx::IntRect& aRect,
+    bool* aOutIsCleared) {
+  MOZ_ASSERT(aScreenTarget);
+  gfx::SurfaceFormat format =
+      aScreenTarget->GetFormat() == gfx::SurfaceFormat::B8G8R8X8
+          ? gfx::SurfaceFormat::B8G8R8X8
+          : gfx::SurfaceFormat::B8G8R8A8;
+  gfx::IntSize size = aRect.Size();
+  gfx::IntSize clientSize = Max(size, GetClientSize().ToUnknownSize());
+
+  *aOutIsCleared = false;
+  // Re-use back buffer if possible
+  if (!mLastBackBuffer ||
+      mLastBackBuffer->GetBackendType() != aScreenTarget->GetBackendType() ||
+      mLastBackBuffer->GetFormat() != format ||
+      mLastBackBuffer->GetSize() != clientSize) {
+    mLastBackBuffer =
+        aScreenTarget->CreateSimilarDrawTarget(clientSize, format);
+    *aOutIsCleared = true;
+  }
+  return do_AddRef(mLastBackBuffer);
+}
+
+already_AddRefed<gfx::SourceSurface> CompositorWidget::EndBackBufferDrawing() {
+  RefPtr<gfx::SourceSurface> surface =
+      mLastBackBuffer ? mLastBackBuffer->Snapshot() : nullptr;
+  return surface.forget();
+}
+
+uint32_t CompositorWidget::GetGLFrameBufferFormat() { return LOCAL_GL_RGBA; }
+
+RefPtr<VsyncObserver> CompositorWidget::GetVsyncObserver() const {
+  // This should only used when the widget is in the GPU process, and should be
+  // implemented by IPDL-enabled CompositorWidgets.
+  // GPU process does not have a CompositorVsyncDispatcher.
+  MOZ_ASSERT_UNREACHABLE("Must be implemented by derived class");
+  return nullptr;
+}
+
+LayoutDeviceIntRegion CompositorWidget::GetTransparentRegion() {
+  // By default, we check the transparency mode to determine if the widget is
+  // transparent, and if so, designate the entire widget drawing area as
+  // transparent. Widgets wanting more complex transparency region determination
+  // should override this method.
+  auto* widget = RealWidget();
+  if (!widget || widget->GetTransparencyMode() != TransparencyMode::Opaque ||
+      widget->WidgetPaintsBackground()) {
+    return LayoutDeviceIntRect(LayoutDeviceIntPoint(0, 0), GetClientSize());
+  }
+  return LayoutDeviceIntRegion();
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/CompositorWidget.h b/widget/CompositorWidget.h
new file mode 100644
index 0000000000..d5e2fb664b
--- /dev/null
+++ b/widget/CompositorWidget.h
@@ -0,0 +1,298 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_CompositorWidget_h__
+#define mozilla_widget_CompositorWidget_h__
+
+#include "nsISupports.h"
+#include "mozilla/RefPtr.h"
+#include "Units.h"
+#include "mozilla/gfx/Rect.h"
+#include "mozilla/layers/CompositorOptions.h"
+#include "mozilla/layers/LayersTypes.h"
+
+#ifdef MOZ_IS_GCC
+#  include "mozilla/layers/NativeLayer.h"
+#endif
+
+class nsIWidget;
+class nsBaseWidget;
+
+namespace mozilla {
+class VsyncObserver;
+namespace gl {
+class GLContext;
+}  // namespace gl
+namespace layers {
+class Compositor;
+class LayerManager;
+class NativeLayerRoot;
+}  // namespace layers
+namespace gfx {
+class DrawTarget;
+class SourceSurface;
+}  // namespace gfx
+namespace widget {
+
+class WinCompositorWidget;
+class GtkCompositorWidget;
+class AndroidCompositorWidget;
+class CompositorWidgetInitData;
+
+// Gecko widgets usually need to communicate with the CompositorWidget with
+// platform-specific messages (for example to update the window size or
+// transparency). This functionality is controlled through a "host". Since
+// this functionality is platform-dependent, it is only forward declared
+// here.
+class PlatformCompositorWidgetDelegate;
+
+// Headless mode uses its own, singular CompositorWidget implementation.
+class HeadlessCompositorWidget;
+
+class CompositorWidgetDelegate {
+ public:
+  virtual PlatformCompositorWidgetDelegate* AsPlatformSpecificDelegate() {
+    return nullptr;
+  }
+
+  virtual HeadlessCompositorWidget* AsHeadlessCompositorWidget() {
+    return nullptr;
+  }
+};
+
+// Platforms that support out-of-process widgets.
+#if defined(XP_WIN) || defined(MOZ_X11) || defined(MOZ_WIDGET_ANDROID) || \
+    defined(MOZ_WAYLAND)
+// CompositorWidgetParent should implement CompositorWidget and
+// PCompositorWidgetParent.
+class CompositorWidgetParent;
+
+// CompositorWidgetChild should implement CompositorWidgetDelegate and
+// PCompositorWidgetChild.
+class CompositorWidgetChild;
+
+#  define MOZ_WIDGET_SUPPORTS_OOP_COMPOSITING
+#endif
+
+class WidgetRenderingContext {
+ public:
+#if defined(XP_MACOSX)
+  gl::GLContext* mGL = nullptr;
+#endif
+};
+
+/**
+ * Access to a widget from the compositor is restricted to these methods.
+ */
+class CompositorWidget {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(mozilla::widget::CompositorWidget)
+
+  /**
+   * Create an in-process compositor widget. aWidget may be ignored if the
+   * platform does not require it.
+   */
+  static RefPtr<CompositorWidget> CreateLocal(
+      const CompositorWidgetInitData& aInitData,
+      const layers::CompositorOptions& aOptions, nsIWidget* aWidget);
+
+  /**
+   * Called before rendering using OMTC. Returns false when the widget is
+   * not ready to be rendered (for example while the window is closed).
+   *
+   * Always called from the compositing thread, which may be the main-thread if
+   * OMTC is not enabled.
+   */
+  virtual bool PreRender(WidgetRenderingContext* aContext) { return true; }
+
+  /**
+   * Called after rendering using OMTC. Not called when rendering was
+   * cancelled by a negative return value from PreRender.
+   *
+   * Always called from the compositing thread, which may be the main-thread if
+   * OMTC is not enabled.
+   */
+  virtual void PostRender(WidgetRenderingContext* aContext) {}
+
+  /**
+   * Called before the first composite. If the result is non-null, one or more
+   * native layers will be placed on the window and used for compositing.
+   * When native layers are used, StartRemoteDrawing(InRegion) and
+   * EndRemoteDrawing(InRegion) will not be called.
+   */
+  virtual RefPtr<layers::NativeLayerRoot> GetNativeLayerRoot() {
+    return nullptr;
+  }
+
+  /**
+   * Return a DrawTarget for the window which can be composited into.
+   *
+   * Only called if GetNativeLayerRoot() returns nullptr.
+   * Called by BasicCompositor on the compositor thread for OMTC drawing
+   * before each composition (unless there's a native layer root).
+   *
+   * The window may specify its buffer mode. If unspecified, it is assumed
+   * to require double-buffering.
+   */
+  virtual already_AddRefed<gfx::DrawTarget> StartRemoteDrawing();
+  virtual already_AddRefed<gfx::DrawTarget> StartRemoteDrawingInRegion(
+      const LayoutDeviceIntRegion& aInvalidRegion,
+      layers::BufferMode* aBufferMode) {
+    return StartRemoteDrawing();
+  }
+
+  /**
+   * Ensure that what was painted into the DrawTarget returned from
+   * StartRemoteDrawing reaches the screen.
+   *
+   * Called by BasicCompositor on the compositor thread for OMTC drawing
+   * after each composition for which StartRemoteDrawing(InRegion) was called.
+   */
+  virtual void EndRemoteDrawing() {}
+  virtual void EndRemoteDrawingInRegion(
+      gfx::DrawTarget* aDrawTarget,
+      const LayoutDeviceIntRegion& aInvalidRegion) {
+    EndRemoteDrawing();
+  }
+
+  /**
+   * Return true when it is better to defer EndRemoteDrawing().
+   *
+   * Called by BasicCompositor on the compositor thread for OMTC drawing
+   * after each composition.
+   */
+  virtual bool NeedsToDeferEndRemoteDrawing() { return false; }
+
+  /**
+   * Some widgets (namely Gtk) may need clean up underlying surface
+   * before painting to draw transparent objects correctly. Return
+   * the transparent region where this clearing is required.
+   */
+  virtual LayoutDeviceIntRegion GetTransparentRegion();
+
+  /**
+   * Called when shutting down the LayerManager to clean-up any cached
+   * resources.
+   *
+   * Always called from the compositing thread.
+   */
+  virtual void CleanupWindowEffects() {}
+
+  /**
+   * A hook for the widget to prepare a Compositor, during the latter's
+   * initialization.
+   *
+   * If this method returns true, it means that the widget will be able to
+   * present frames from the compoositor.
+   *
+   * Returning false will cause the compositor's initialization to fail, and
+   * a different compositor backend will be used (if any).
+   */
+  virtual bool InitCompositor(layers::Compositor* aCompositor) { return true; }
+
+  /**
+   * A hook that is ran whenever composition is resumed.
+   *
+   * This is called from CompositorBridgeParent::ResumeComposition,
+   * immediately prior to webrender being resumed.
+   *
+   * Returns true if composition can be successfully resumed, else false.
+   */
+  virtual bool OnResumeComposition() { return true; }
+
+  /**
+   * Return the size of the drawable area of the widget.
+   */
+  virtual LayoutDeviceIntSize GetClientSize() = 0;
+
+  /**
+   * Return the internal format of the default framebuffer for this
+   * widget.
+   */
+  virtual uint32_t GetGLFrameBufferFormat();
+
+  /*
+   * Access the underlying nsIWidget. This method will be removed when the
+   * compositor no longer depends on nsIWidget on any platform.
+   */
+  virtual nsIWidget* RealWidget() = 0;
+
+  /**
+   * Clean up any resources used by Start/EndRemoteDrawing.
+   *
+   * Called by BasicCompositor on the compositor thread for OMTC drawing
+   * when the compositor is destroyed.
+   */
+  virtual void CleanupRemoteDrawing();
+
+  /**
+   * Return a key that can represent the widget object round-trip across the
+   * CompositorBridge channel. This only needs to be implemented on GTK and
+   * Windows.
+   *
+   * The key must be the nsIWidget pointer cast to a uintptr_t. See
+   * CompositorBridgeChild::RecvHideAllPlugins and
+   * CompositorBridgeParent::SendHideAllPlugins.
+   */
+  virtual uintptr_t GetWidgetKey() { return 0; }
+
+  /**
+   * Create a backbuffer for the software compositor.
+   */
+  virtual already_AddRefed<gfx::DrawTarget> GetBackBufferDrawTarget(
+      gfx::DrawTarget* aScreenTarget, const gfx::IntRect& aRect,
+      bool* aOutIsCleared);
+
+  /**
+   * Ensure end of composition to back buffer.
+   *
+   * Called by BasicCompositor on the compositor thread for OMTC drawing
+   * after each composition to back buffer.
+   */
+  virtual already_AddRefed<gfx::SourceSurface> EndBackBufferDrawing();
+
+  /**
+   * Observe or unobserve vsync.
+   */
+  virtual void ObserveVsync(VsyncObserver* aObserver) = 0;
+
+  /**
+   * Get the compositor options for the compositor associated with this
+   * CompositorWidget.
+   */
+  const layers::CompositorOptions& GetCompositorOptions() { return mOptions; }
+
+  /**
+   * Return true if the window is hidden and should not be composited.
+   */
+  virtual bool IsHidden() const { return false; }
+
+  /**
+   * This is only used by out-of-process compositors.
+   */
+  virtual RefPtr<VsyncObserver> GetVsyncObserver() const;
+
+  virtual WinCompositorWidget* AsWindows() { return nullptr; }
+  virtual GtkCompositorWidget* AsGTK() { return nullptr; }
+  virtual AndroidCompositorWidget* AsAndroid() { return nullptr; }
+
+  /**
+   * Return the platform-specific delegate for the widget, if any.
+   */
+  virtual CompositorWidgetDelegate* AsDelegate() { return nullptr; }
+
+ protected:
+  explicit CompositorWidget(const layers::CompositorOptions& aOptions);
+  virtual ~CompositorWidget();
+
+  // Back buffer of BasicCompositor
+  RefPtr<gfx::DrawTarget> mLastBackBuffer;
+
+  layers::CompositorOptions mOptions;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/ContentCache.cpp b/widget/ContentCache.cpp
new file mode 100644
index 0000000000..b6093fb3f7
--- /dev/null
+++ b/widget/ContentCache.cpp
@@ -0,0 +1,2011 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ContentCache.h"
+
+#include <utility>
+
+#include "IMEData.h"
+#include "TextEvents.h"
+
+#include "mozilla/Assertions.h"
+#include "mozilla/IMEStateManager.h"
+#include "mozilla/IntegerPrintfMacros.h"
+#include "mozilla/Logging.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/TextComposition.h"
+#include "mozilla/dom/BrowserParent.h"
+#include "nsExceptionHandler.h"
+#include "nsIWidget.h"
+#include "nsPrintfCString.h"
+
+namespace mozilla {
+
+using namespace dom;
+using namespace widget;
+
+static const char* GetBoolName(bool aBool) { return aBool ? "true" : "false"; }
+
+static const char* GetNotificationName(const IMENotification* aNotification) {
+  if (!aNotification) {
+    return "Not notification";
+  }
+  return ToChar(aNotification->mMessage);
+}
+
+/*****************************************************************************
+ * mozilla::ContentCache
+ *****************************************************************************/
+
+LazyLogModule sContentCacheLog("ContentCacheWidgets");
+
+bool ContentCache::IsValid() const {
+  if (mText.isNothing()) {
+    // mSelection and mCaret depend on mText.
+    if (NS_WARN_IF(mSelection.isSome()) || NS_WARN_IF(mCaret.isSome())) {
+      return false;
+    }
+  } else {
+    // mSelection depends on mText.
+    if (mSelection.isSome() && NS_WARN_IF(!mSelection->IsValidIn(*mText))) {
+      return false;
+    }
+
+    // mCaret depends on mSelection.
+    if (mCaret.isSome() &&
+        (NS_WARN_IF(mSelection.isNothing()) ||
+         NS_WARN_IF(!mSelection->mHasRange) ||
+         NS_WARN_IF(mSelection->StartOffset() != mCaret->Offset()))) {
+      return false;
+    }
+  }
+
+  // mTextRectArray stores character rects around composition string.
+  // Note that even if we fail to collect the rects, we may keep storing
+  // mCompositionStart.
+  if (mTextRectArray.isSome()) {
+    if (NS_WARN_IF(mCompositionStart.isNothing())) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+void ContentCache::AssertIfInvalid() const {
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  if (IsValid()) {
+    return;
+  }
+
+  // This text will appear in the crash reports without any permissions.
+  // Do not use `ToString` here to avoid to expose unexpected data with
+  // changing the type or `operator<<()`.
+  nsPrintfCString info(
+      "ContentCache={ mText=%s, mSelection=%s, mCaret=%s, mTextRectArray=%s, "
+      "mCompositionStart=%s }\n",
+      // Don't expose mText.ref() value for protecting the user's privacy.
+      mText.isNothing()
+          ? "Nothing"
+          : nsPrintfCString("{ Length()=%zu }", mText->Length()).get(),
+      mSelection.isNothing()
+          ? "Nothing"
+          : nsPrintfCString("{ mAnchor=%u, mFocus=%u }", mSelection->mAnchor,
+                            mSelection->mFocus)
+                .get(),
+      mCaret.isNothing()
+          ? "Nothing"
+          : nsPrintfCString("{ mOffset=%u }", mCaret->mOffset).get(),
+      mTextRectArray.isNothing()
+          ? "Nothing"
+          : nsPrintfCString("{ Length()=%u }", mTextRectArray->Length()).get(),
+      mCompositionStart.isNothing()
+          ? "Nothing"
+          : nsPrintfCString("%u", mCompositionStart.value()).get());
+  CrashReporter::AppendAppNotesToCrashReport(info);
+  MOZ_DIAGNOSTIC_ASSERT(false, "Invalid ContentCache data");
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+}
+
+/*****************************************************************************
+ * mozilla::ContentCacheInChild
+ *****************************************************************************/
+
+void ContentCacheInChild::Clear() {
+  MOZ_LOG(sContentCacheLog, LogLevel::Info, ("0x%p Clear()", this));
+
+  mCompositionStart.reset();
+  mLastCommit.reset();
+  mText.reset();
+  mSelection.reset();
+  mFirstCharRect.SetEmpty();
+  mCaret.reset();
+  mTextRectArray.reset();
+  mLastCommitStringTextRectArray.reset();
+  mEditorRect.SetEmpty();
+}
+
+void ContentCacheInChild::OnCompositionEvent(
+    const WidgetCompositionEvent& aCompositionEvent) {
+  if (aCompositionEvent.CausesDOMCompositionEndEvent()) {
+    RefPtr<TextComposition> composition =
+        IMEStateManager::GetTextCompositionFor(aCompositionEvent.mWidget);
+    if (composition) {
+      nsAutoString lastCommitString;
+      if (aCompositionEvent.mMessage == eCompositionCommitAsIs) {
+        lastCommitString = composition->CommitStringIfCommittedAsIs();
+      } else {
+        lastCommitString = aCompositionEvent.mData;
+      }
+      // We don't need to store canceling information because this is required
+      // by undoing of last commit (Kakutei-Undo of Japanese IME).
+      if (!lastCommitString.IsEmpty()) {
+        mLastCommit = Some(OffsetAndData<uint32_t>(
+            composition->NativeOffsetOfStartComposition(), lastCommitString));
+        MOZ_LOG(
+            sContentCacheLog, LogLevel::Debug,
+            ("0x%p OnCompositionEvent(), stored last composition string data "
+             "(aCompositionEvent={ mMessage=%s, mData=\"%s\"}, mLastCommit=%s)",
+             this, ToChar(aCompositionEvent.mMessage),
+             PrintStringDetail(
+                 aCompositionEvent.mData,
+                 PrintStringDetail::kMaxLengthForCompositionString)
+                 .get(),
+             ToString(mLastCommit).c_str()));
+        return;
+      }
+    }
+  }
+  if (mLastCommit.isSome()) {
+    MOZ_LOG(
+        sContentCacheLog, LogLevel::Debug,
+        ("0x%p OnCompositionEvent(), resetting the last composition string "
+         "data (aCompositionEvent={ mMessage=%s, mData=\"%s\"}, "
+         "mLastCommit=%s)",
+         this, ToChar(aCompositionEvent.mMessage),
+         PrintStringDetail(aCompositionEvent.mData,
+                           PrintStringDetail::kMaxLengthForCompositionString)
+             .get(),
+         ToString(mLastCommit).c_str()));
+    mLastCommit.reset();
+  }
+}
+
+bool ContentCacheInChild::CacheAll(nsIWidget* aWidget,
+                                   const IMENotification* aNotification) {
+  MOZ_LOG(sContentCacheLog, LogLevel::Info,
+          ("0x%p CacheAll(aWidget=0x%p, aNotification=%s)", this, aWidget,
+           GetNotificationName(aNotification)));
+
+  const bool textCached = CacheText(aWidget, aNotification);
+  const bool editorRectCached = CacheEditorRect(aWidget, aNotification);
+  AssertIfInvalid();
+  return (textCached || editorRectCached) && IsValid();
+}
+
+bool ContentCacheInChild::CacheSelection(nsIWidget* aWidget,
+                                         const IMENotification* aNotification) {
+  MOZ_LOG(
+      sContentCacheLog, LogLevel::Info,
+      ("0x%p CacheSelection(aWidget=0x%p, aNotification=%s), mText=%s", this,
+       aWidget, GetNotificationName(aNotification),
+       PrintStringDetail(mText, PrintStringDetail::kMaxLengthForEditor).get()));
+
+  mSelection.reset();
+  mCaret.reset();
+
+  if (mText.isNothing()) {
+    return false;
+  }
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  WidgetQueryContentEvent querySelectedTextEvent(true, eQuerySelectedText,
+                                                 aWidget);
+  aWidget->DispatchEvent(&querySelectedTextEvent, status);
+  if (NS_WARN_IF(querySelectedTextEvent.Failed())) {
+    MOZ_LOG(
+        sContentCacheLog, LogLevel::Error,
+        ("0x%p CacheSelection(), FAILED, couldn't retrieve the selected text",
+         this));
+    // XXX Allowing selection-independent character rects makes things
+    //     complicated in the parent...
+  }
+  // ContentCache should store only editable content.  Therefore, if current
+  // selection root is not editable, we don't need to store the selection, i.e.,
+  // let's treat it as there is no selection.  However, if we already have
+  // previously editable text, let's store the selection even if it becomes
+  // uneditable because not doing so would create odd situation.  E.g., IME may
+  // fail only querying selection after succeeded querying text.
+  else if (NS_WARN_IF(!querySelectedTextEvent.mReply->mIsEditableContent)) {
+    MOZ_LOG(sContentCacheLog, LogLevel::Error,
+            ("0x%p CacheSelection(), FAILED, editable content had already been "
+             "blurred",
+             this));
+    AssertIfInvalid();
+    return false;
+  } else {
+    mSelection.emplace(querySelectedTextEvent);
+  }
+
+  return (CacheCaretAndTextRects(aWidget, aNotification) ||
+          querySelectedTextEvent.Succeeded()) &&
+         IsValid();
+}
+
+bool ContentCacheInChild::CacheCaret(nsIWidget* aWidget,
+                                     const IMENotification* aNotification) {
+  mCaret.reset();
+
+  if (mSelection.isNothing()) {
+    return false;
+  }
+
+  MOZ_LOG(sContentCacheLog, LogLevel::Info,
+          ("0x%p CacheCaret(aWidget=0x%p, aNotification=%s)", this, aWidget,
+           GetNotificationName(aNotification)));
+
+  if (mSelection->mHasRange) {
+    // XXX Should be mSelection.mFocus?
+    const uint32_t offset = mSelection->StartOffset();
+
+    nsEventStatus status = nsEventStatus_eIgnore;
+    WidgetQueryContentEvent queryCaretRectEvent(true, eQueryCaretRect, aWidget);
+    queryCaretRectEvent.InitForQueryCaretRect(offset);
+    aWidget->DispatchEvent(&queryCaretRectEvent, status);
+    if (NS_WARN_IF(queryCaretRectEvent.Failed())) {
+      MOZ_LOG(sContentCacheLog, LogLevel::Error,
+              ("0x%p   CacheCaret(), FAILED, couldn't retrieve the caret rect "
+               "at offset=%u",
+               this, offset));
+      return false;
+    }
+    mCaret.emplace(offset, queryCaretRectEvent.mReply->mRect);
+  }
+  MOZ_LOG(sContentCacheLog, LogLevel::Info,
+          ("0x%p   CacheCaret(), Succeeded, mSelection=%s, mCaret=%s", this,
+           ToString(mSelection).c_str(), ToString(mCaret).c_str()));
+  AssertIfInvalid();
+  return IsValid();
+}
+
+bool ContentCacheInChild::CacheEditorRect(
+    nsIWidget* aWidget, const IMENotification* aNotification) {
+  MOZ_LOG(sContentCacheLog, LogLevel::Info,
+          ("0x%p CacheEditorRect(aWidget=0x%p, aNotification=%s)", this,
+           aWidget, GetNotificationName(aNotification)));
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  WidgetQueryContentEvent queryEditorRectEvent(true, eQueryEditorRect, aWidget);
+  aWidget->DispatchEvent(&queryEditorRectEvent, status);
+  if (NS_WARN_IF(queryEditorRectEvent.Failed())) {
+    MOZ_LOG(
+        sContentCacheLog, LogLevel::Error,
+        ("0x%p   CacheEditorRect(), FAILED, couldn't retrieve the editor rect",
+         this));
+    return false;
+  }
+  // ContentCache should store only editable content.  Therefore, if current
+  // selection root is not editable, we don't need to store the editor rect,
+  // i.e., let's treat it as there is no focused editor.
+  if (NS_WARN_IF(!queryEditorRectEvent.mReply->mIsEditableContent)) {
+    MOZ_LOG(sContentCacheLog, LogLevel::Error,
+            ("0x%p   CacheText(), FAILED, editable content had already been "
+             "blurred",
+             this));
+    return false;
+  }
+  mEditorRect = queryEditorRectEvent.mReply->mRect;
+  MOZ_LOG(sContentCacheLog, LogLevel::Info,
+          ("0x%p   CacheEditorRect(), Succeeded, mEditorRect=%s", this,
+           ToString(mEditorRect).c_str()));
+  return true;
+}
+
+bool ContentCacheInChild::CacheCaretAndTextRects(
+    nsIWidget* aWidget, const IMENotification* aNotification) {
+  MOZ_LOG(sContentCacheLog, LogLevel::Info,
+          ("0x%p CacheCaretAndTextRects(aWidget=0x%p, aNotification=%s)", this,
+           aWidget, GetNotificationName(aNotification)));
+
+  const bool caretCached = CacheCaret(aWidget, aNotification);
+  const bool textRectsCached = CacheTextRects(aWidget, aNotification);
+  AssertIfInvalid();
+  return (caretCached || textRectsCached) && IsValid();
+}
+
+bool ContentCacheInChild::CacheText(nsIWidget* aWidget,
+                                    const IMENotification* aNotification) {
+  MOZ_LOG(sContentCacheLog, LogLevel::Info,
+          ("0x%p CacheText(aWidget=0x%p, aNotification=%s)", this, aWidget,
+           GetNotificationName(aNotification)));
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  WidgetQueryContentEvent queryTextContentEvent(true, eQueryTextContent,
+                                                aWidget);
+  queryTextContentEvent.InitForQueryTextContent(0, UINT32_MAX);
+  aWidget->DispatchEvent(&queryTextContentEvent, status);
+  if (NS_WARN_IF(queryTextContentEvent.Failed())) {
+    MOZ_LOG(sContentCacheLog, LogLevel::Error,
+            ("0x%p   CacheText(), FAILED, couldn't retrieve whole text", this));
+    mText.reset();
+  }
+  // ContentCache should store only editable content.  Therefore, if current
+  // selection root is not editable, we don't need to store the text, i.e.,
+  // let's treat it as there is no editable text.
+  else if (NS_WARN_IF(!queryTextContentEvent.mReply->mIsEditableContent)) {
+    MOZ_LOG(sContentCacheLog, LogLevel::Error,
+            ("0x%p   CacheText(), FAILED, editable content had already been "
+             "blurred",
+             this));
+    mText.reset();
+  } else {
+    mText = Some(nsString(queryTextContentEvent.mReply->DataRef()));
+    MOZ_LOG(sContentCacheLog, LogLevel::Info,
+            ("0x%p   CacheText(), Succeeded, mText=%s", this,
+             PrintStringDetail(mText, PrintStringDetail::kMaxLengthForEditor)
+                 .get()));
+  }
+
+  // Forget last commit range if string in the range is different from the
+  // last commit string.
+  if (mLastCommit.isSome() &&
+      (mText.isNothing() ||
+       nsDependentSubstring(mText.ref(), mLastCommit->StartOffset(),
+                            mLastCommit->Length()) != mLastCommit->DataRef())) {
+    MOZ_LOG(sContentCacheLog, LogLevel::Debug,
+            ("0x%p   CacheText(), resetting the last composition string data "
+             "(mLastCommit=%s, current string=\"%s\")",
+             this, ToString(mLastCommit).c_str(),
+             PrintStringDetail(
+                 nsDependentSubstring(mText.ref(), mLastCommit->StartOffset(),
+                                      mLastCommit->Length()),
+                 PrintStringDetail::kMaxLengthForCompositionString)
+                 .get()));
+    mLastCommit.reset();
+  }
+
+  // If we fail to get editable text content, it must mean that there is no
+  // focused element anymore or focused element is not editable.  In this case,
+  // we should not get selection of non-editable content
+  if (MOZ_UNLIKELY(mText.isNothing())) {
+    mSelection.reset();
+    mCaret.reset();
+    mTextRectArray.reset();
+    AssertIfInvalid();
+    return false;
+  }
+
+  return CacheSelection(aWidget, aNotification);
+}
+
+bool ContentCacheInChild::QueryCharRect(nsIWidget* aWidget, uint32_t aOffset,
+                                        LayoutDeviceIntRect& aCharRect) const {
+  aCharRect.SetEmpty();
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  WidgetQueryContentEvent queryTextRectEvent(true, eQueryTextRect, aWidget);
+  queryTextRectEvent.InitForQueryTextRect(aOffset, 1);
+  aWidget->DispatchEvent(&queryTextRectEvent, status);
+  if (NS_WARN_IF(queryTextRectEvent.Failed())) {
+    return false;
+  }
+  aCharRect = queryTextRectEvent.mReply->mRect;
+
+  // Guarantee the rect is not empty.
+  if (NS_WARN_IF(!aCharRect.Height())) {
+    aCharRect.SetHeight(1);
+  }
+  if (NS_WARN_IF(!aCharRect.Width())) {
+    aCharRect.SetWidth(1);
+  }
+  return true;
+}
+
+bool ContentCacheInChild::QueryCharRectArray(nsIWidget* aWidget,
+                                             uint32_t aOffset, uint32_t aLength,
+                                             RectArray& aCharRectArray) const {
+  nsEventStatus status = nsEventStatus_eIgnore;
+  WidgetQueryContentEvent queryTextRectsEvent(true, eQueryTextRectArray,
+                                              aWidget);
+  queryTextRectsEvent.InitForQueryTextRectArray(aOffset, aLength);
+  aWidget->DispatchEvent(&queryTextRectsEvent, status);
+  if (NS_WARN_IF(queryTextRectsEvent.Failed())) {
+    aCharRectArray.Clear();
+    return false;
+  }
+  aCharRectArray = std::move(queryTextRectsEvent.mReply->mRectArray);
+  return true;
+}
+
+bool ContentCacheInChild::CacheTextRects(nsIWidget* aWidget,
+                                         const IMENotification* aNotification) {
+  MOZ_LOG(
+      sContentCacheLog, LogLevel::Info,
+      ("0x%p CacheTextRects(aWidget=0x%p, aNotification=%s), mCaret=%s", this,
+       aWidget, GetNotificationName(aNotification), ToString(mCaret).c_str()));
+
+  if (mSelection.isSome()) {
+    mSelection->ClearRects();
+  }
+
+  // Retrieve text rects in composition string if there is.
+  RefPtr<TextComposition> textComposition =
+      IMEStateManager::GetTextCompositionFor(aWidget);
+  if (textComposition) {
+    // mCompositionStart may be updated by some composition event handlers.
+    // So, let's update it with the latest information.
+    mCompositionStart = Some(textComposition->NativeOffsetOfStartComposition());
+    // Note that TextComposition::String() may not be modified here because
+    // it's modified after all edit action listeners are performed but this
+    // is called while some of them are performed.
+    // FYI: For supporting IME which commits composition and restart new
+    //      composition immediately, we should cache next character of current
+    //      composition too.
+    uint32_t length = textComposition->LastData().Length() + 1;
+    mTextRectArray = Some(TextRectArray(mCompositionStart.value()));
+    if (NS_WARN_IF(!QueryCharRectArray(aWidget, mTextRectArray->mStart, length,
+                                       mTextRectArray->mRects))) {
+      MOZ_LOG(sContentCacheLog, LogLevel::Error,
+              ("0x%p   CacheTextRects(), FAILED, "
+               "couldn't retrieve text rect array of the composition string",
+               this));
+      mTextRectArray.reset();
+    }
+  } else {
+    mCompositionStart.reset();
+    mTextRectArray.reset();
+  }
+
+  if (mSelection.isSome()) {
+    // Set mSelection->mAnchorCharRects
+    // If we've already have the rect in mTextRectArray, save the query cost.
+    if (mSelection->mHasRange && mTextRectArray.isSome() &&
+        mTextRectArray->IsOffsetInRange(mSelection->mAnchor) &&
+        (!mSelection->mAnchor ||
+         mTextRectArray->IsOffsetInRange(mSelection->mAnchor - 1))) {
+      mSelection->mAnchorCharRects[eNextCharRect] =
+          mTextRectArray->GetRect(mSelection->mAnchor);
+      if (mSelection->mAnchor) {
+        mSelection->mAnchorCharRects[ePrevCharRect] =
+            mTextRectArray->GetRect(mSelection->mAnchor - 1);
+      }
+    }
+    // Otherwise, get it from content even if there is no selection ranges.
+    else {
+      RectArray rects;
+      const uint32_t startOffset = mSelection->mHasRange && mSelection->mAnchor
+                                       ? mSelection->mAnchor - 1u
+                                       : 0u;
+      const uint32_t length =
+          mSelection->mHasRange && mSelection->mAnchor ? 2u : 1u;
+      if (NS_WARN_IF(
+              !QueryCharRectArray(aWidget, startOffset, length, rects))) {
+        MOZ_LOG(
+            sContentCacheLog, LogLevel::Error,
+            ("0x%p   CacheTextRects(), FAILED, couldn't retrieve text rect "
+             "array around the selection anchor (%s)",
+             this,
+             mSelection ? ToString(mSelection->mAnchor).c_str() : "Nothing"));
+        MOZ_ASSERT_IF(mSelection.isSome(),
+                      mSelection->mAnchorCharRects[ePrevCharRect].IsEmpty());
+        MOZ_ASSERT_IF(mSelection.isSome(),
+                      mSelection->mAnchorCharRects[eNextCharRect].IsEmpty());
+      } else if (rects.Length()) {
+        if (rects.Length() > 1) {
+          mSelection->mAnchorCharRects[ePrevCharRect] = rects[0];
+          mSelection->mAnchorCharRects[eNextCharRect] = rects[1];
+        } else {
+          mSelection->mAnchorCharRects[eNextCharRect] = rects[0];
+          MOZ_ASSERT(mSelection->mAnchorCharRects[ePrevCharRect].IsEmpty());
+        }
+      }
+    }
+
+    // Set mSelection->mFocusCharRects
+    // If selection is collapsed (including no selection case), the focus char
+    // rects are same as the anchor char rects so that we can just copy them.
+    if (mSelection->IsCollapsed()) {
+      mSelection->mFocusCharRects[0] = mSelection->mAnchorCharRects[0];
+      mSelection->mFocusCharRects[1] = mSelection->mAnchorCharRects[1];
+    }
+    // If the selection range is in mTextRectArray, save the query cost.
+    else if (mTextRectArray.isSome() &&
+             mTextRectArray->IsOffsetInRange(mSelection->mFocus) &&
+             (!mSelection->mFocus ||
+              mTextRectArray->IsOffsetInRange(mSelection->mFocus - 1))) {
+      MOZ_ASSERT(mSelection->mHasRange);
+      mSelection->mFocusCharRects[eNextCharRect] =
+          mTextRectArray->GetRect(mSelection->mFocus);
+      if (mSelection->mFocus) {
+        mSelection->mFocusCharRects[ePrevCharRect] =
+            mTextRectArray->GetRect(mSelection->mFocus - 1);
+      }
+    }
+    // Otherwise, including no selection range cases, need to query the rects.
+    else {
+      MOZ_ASSERT(mSelection->mHasRange);
+      RectArray rects;
+      const uint32_t startOffset =
+          mSelection->mFocus ? mSelection->mFocus - 1u : 0u;
+      const uint32_t length = mSelection->mFocus ? 2u : 1u;
+      if (NS_WARN_IF(
+              !QueryCharRectArray(aWidget, startOffset, length, rects))) {
+        MOZ_LOG(
+            sContentCacheLog, LogLevel::Error,
+            ("0x%p   CacheTextRects(), FAILED, couldn't retrieve text rect "
+             "array around the selection focus (%s)",
+             this,
+             mSelection ? ToString(mSelection->mFocus).c_str() : "Nothing"));
+        MOZ_ASSERT_IF(mSelection.isSome(),
+                      mSelection->mFocusCharRects[ePrevCharRect].IsEmpty());
+        MOZ_ASSERT_IF(mSelection.isSome(),
+                      mSelection->mFocusCharRects[eNextCharRect].IsEmpty());
+      } else if (NS_WARN_IF(mSelection.isNothing())) {
+        MOZ_LOG(sContentCacheLog, LogLevel::Error,
+                ("0x%p   CacheTextRects(), FAILED, mSelection was reset during "
+                 "the call of QueryCharRectArray",
+                 this));
+      } else {
+        if (rects.Length() > 1) {
+          mSelection->mFocusCharRects[ePrevCharRect] = rects[0];
+          mSelection->mFocusCharRects[eNextCharRect] = rects[1];
+        } else if (rects.Length()) {
+          mSelection->mFocusCharRects[eNextCharRect] = rects[0];
+          MOZ_ASSERT(mSelection->mFocusCharRects[ePrevCharRect].IsEmpty());
+        }
+      }
+    }
+  }
+
+  // If there is a non-collapsed selection range, let's query the whole selected
+  // text rect.  Note that the result cannot be computed from first character
+  // rect and last character rect of the selection because they both may be in
+  // middle of different line.
+  if (mSelection.isSome() && mSelection->mHasRange &&
+      !mSelection->IsCollapsed()) {
+    nsEventStatus status = nsEventStatus_eIgnore;
+    WidgetQueryContentEvent queryTextRectEvent(true, eQueryTextRect, aWidget);
+    queryTextRectEvent.InitForQueryTextRect(mSelection->StartOffset(),
+                                            mSelection->Length());
+    aWidget->DispatchEvent(&queryTextRectEvent, status);
+    if (NS_WARN_IF(queryTextRectEvent.Failed())) {
+      MOZ_LOG(sContentCacheLog, LogLevel::Error,
+              ("0x%p   CacheTextRects(), FAILED, "
+               "couldn't retrieve text rect of whole selected text",
+               this));
+    } else {
+      mSelection->mRect = queryTextRectEvent.mReply->mRect;
+    }
+  }
+
+  // Even if there is no selection range, we should have the first character
+  // rect for the last resort of suggesting position of IME UI.
+  if (mSelection.isSome() && mSelection->mHasRange && !mSelection->mFocus) {
+    mFirstCharRect = mSelection->mFocusCharRects[eNextCharRect];
+  } else if (mSelection.isSome() && mSelection->mHasRange &&
+             mSelection->mFocus == 1) {
+    mFirstCharRect = mSelection->mFocusCharRects[ePrevCharRect];
+  } else if (mSelection.isSome() && mSelection->mHasRange &&
+             !mSelection->mAnchor) {
+    mFirstCharRect = mSelection->mAnchorCharRects[eNextCharRect];
+  } else if (mSelection.isSome() && mSelection->mHasRange &&
+             mSelection->mAnchor == 1) {
+    mFirstCharRect = mSelection->mFocusCharRects[ePrevCharRect];
+  } else if (mTextRectArray.isSome() && mTextRectArray->IsOffsetInRange(0u)) {
+    mFirstCharRect = mTextRectArray->GetRect(0u);
+  } else {
+    LayoutDeviceIntRect charRect;
+    if (MOZ_UNLIKELY(NS_WARN_IF(!QueryCharRect(aWidget, 0, charRect)))) {
+      MOZ_LOG(sContentCacheLog, LogLevel::Error,
+              ("0x%p   CacheTextRects(), FAILED, "
+               "couldn't retrieve first char rect",
+               this));
+      mFirstCharRect.SetEmpty();
+    } else {
+      mFirstCharRect = charRect;
+    }
+  }
+
+  // Finally, let's cache the last commit string's character rects until
+  // selection change or something other editing because user may reconvert
+  // or undo the last commit.  Then, IME requires the character rects for
+  // positioning their UI.
+  if (mLastCommit.isSome()) {
+    mLastCommitStringTextRectArray =
+        Some(TextRectArray(mLastCommit->StartOffset()));
+    if (mLastCommit->Length() == 1 && mSelection.isSome() &&
+        mSelection->mHasRange &&
+        mSelection->mAnchor - 1 == mLastCommit->StartOffset() &&
+        !mSelection->mAnchorCharRects[ePrevCharRect].IsEmpty()) {
+      mLastCommitStringTextRectArray->mRects.AppendElement(
+          mSelection->mAnchorCharRects[ePrevCharRect]);
+    } else if (NS_WARN_IF(!QueryCharRectArray(
+                   aWidget, mLastCommit->StartOffset(), mLastCommit->Length(),
+                   mLastCommitStringTextRectArray->mRects))) {
+      MOZ_LOG(sContentCacheLog, LogLevel::Error,
+              ("0x%p   CacheTextRects(), FAILED, "
+               "couldn't retrieve text rect array of the last commit string",
+               this));
+      mLastCommitStringTextRectArray.reset();
+      mLastCommit.reset();
+    }
+    MOZ_ASSERT((mLastCommitStringTextRectArray.isSome()
+                    ? mLastCommitStringTextRectArray->mRects.Length()
+                    : 0) == (mLastCommit.isSome() ? mLastCommit->Length() : 0));
+  } else {
+    mLastCommitStringTextRectArray.reset();
+  }
+
+  MOZ_LOG(
+      sContentCacheLog, LogLevel::Info,
+      ("0x%p   CacheTextRects(), Succeeded, "
+       "mText=%s, mTextRectArray=%s, mSelection=%s, "
+       "mFirstCharRect=%s, mLastCommitStringTextRectArray=%s",
+       this,
+       PrintStringDetail(mText, PrintStringDetail::kMaxLengthForEditor).get(),
+       ToString(mTextRectArray).c_str(), ToString(mSelection).c_str(),
+       ToString(mFirstCharRect).c_str(),
+       ToString(mLastCommitStringTextRectArray).c_str()));
+  AssertIfInvalid();
+  return IsValid();
+}
+
+bool ContentCacheInChild::SetSelection(
+    nsIWidget* aWidget,
+    const IMENotification::SelectionChangeDataBase& aSelectionChangeData) {
+  MOZ_LOG(
+      sContentCacheLog, LogLevel::Info,
+      ("0x%p SetSelection(aSelectionChangeData=%s), mText=%s", this,
+       ToString(aSelectionChangeData).c_str(),
+       PrintStringDetail(mText, PrintStringDetail::kMaxLengthForEditor).get()));
+
+  if (MOZ_UNLIKELY(mText.isNothing())) {
+    return false;
+  }
+
+  mSelection = Some(Selection(aSelectionChangeData));
+
+  if (mLastCommit.isSome()) {
+    // Forget last commit string range if selection is not collapsed
+    // at end of the last commit string.
+    if (!mSelection->mHasRange || !mSelection->IsCollapsed() ||
+        mSelection->mAnchor != mLastCommit->EndOffset()) {
+      MOZ_LOG(
+          sContentCacheLog, LogLevel::Debug,
+          ("0x%p   SetSelection(), forgetting last commit composition data "
+           "(mSelection=%s, mLastCommit=%s)",
+           this, ToString(mSelection).c_str(), ToString(mLastCommit).c_str()));
+      mLastCommit.reset();
+    }
+  }
+
+  CacheCaret(aWidget);
+  CacheTextRects(aWidget);
+
+  return mSelection.isSome() && IsValid();
+}
+
+/*****************************************************************************
+ * mozilla::ContentCacheInParent
+ *****************************************************************************/
+
+ContentCacheInParent::ContentCacheInParent(BrowserParent& aBrowserParent)
+    : mBrowserParent(aBrowserParent),
+      mCommitStringByRequest(nullptr),
+      mPendingCommitLength(0),
+      mIsChildIgnoringCompositionEvents(false) {}
+
+void ContentCacheInParent::AssignContent(const ContentCache& aOther,
+                                         nsIWidget* aWidget,
+                                         const IMENotification* aNotification) {
+  MOZ_DIAGNOSTIC_ASSERT(aOther.IsValid());
+
+  mText = aOther.mText;
+  mSelection = aOther.mSelection;
+  mFirstCharRect = aOther.mFirstCharRect;
+  mCaret = aOther.mCaret;
+  mTextRectArray = aOther.mTextRectArray;
+  mLastCommitStringTextRectArray = aOther.mLastCommitStringTextRectArray;
+  mEditorRect = aOther.mEditorRect;
+
+  // Only when there is one composition, the TextComposition instance in this
+  // process is managing the composition in the remote process.  Therefore,
+  // we shouldn't update composition start offset of TextComposition with
+  // old composition which is still being handled by the child process.
+  if (WidgetHasComposition() && mHandlingCompositions.Length() == 1 &&
+      mCompositionStart.isSome()) {
+    IMEStateManager::MaybeStartOffsetUpdatedInChild(aWidget,
+                                                    mCompositionStart.value());
+  }
+
+  // When this instance allows to query content relative to composition string,
+  // we should modify mCompositionStart with the latest information in the
+  // remote process because now we have the information around the composition
+  // string.
+  mCompositionStartInChild = aOther.mCompositionStart;
+  if (WidgetHasComposition() || HasPendingCommit()) {
+    if (mCompositionStartInChild.isSome()) {
+      if (mCompositionStart.valueOr(UINT32_MAX) !=
+          mCompositionStartInChild.value()) {
+        mCompositionStart = mCompositionStartInChild;
+        mPendingCommitLength = 0;
+      }
+    } else if (mCompositionStart.isSome() && mSelection.isSome() &&
+               mSelection->mHasRange &&
+               mCompositionStart.value() != mSelection->StartOffset()) {
+      mCompositionStart = Some(mSelection->StartOffset());
+      mPendingCommitLength = 0;
+    }
+  }
+
+  MOZ_LOG(
+      sContentCacheLog, LogLevel::Info,
+      ("0x%p   AssignContent(aNotification=%s), "
+       "Succeeded, mText=%s, mSelection=%s, mFirstCharRect=%s, "
+       "mCaret=%s, mTextRectArray=%s, WidgetHasComposition()=%s, "
+       "mHandlingCompositions.Length()=%zu, mCompositionStart=%s, "
+       "mPendingCommitLength=%u, mEditorRect=%s, "
+       "mLastCommitStringTextRectArray=%s",
+       this, GetNotificationName(aNotification),
+       PrintStringDetail(mText, PrintStringDetail::kMaxLengthForEditor).get(),
+       ToString(mSelection).c_str(), ToString(mFirstCharRect).c_str(),
+       ToString(mCaret).c_str(), ToString(mTextRectArray).c_str(),
+       GetBoolName(WidgetHasComposition()), mHandlingCompositions.Length(),
+       ToString(mCompositionStart).c_str(), mPendingCommitLength,
+       ToString(mEditorRect).c_str(),
+       ToString(mLastCommitStringTextRectArray).c_str()));
+}
+
+bool ContentCacheInParent::HandleQueryContentEvent(
+    WidgetQueryContentEvent& aEvent, nsIWidget* aWidget) const {
+  MOZ_ASSERT(aWidget);
+
+  // ContentCache doesn't store offset of its start with XP linebreaks.
+  // So, we don't support to query contents relative to composition start
+  // offset with XP linebreaks.
+  if (NS_WARN_IF(!aEvent.mUseNativeLineBreak)) {
+    MOZ_LOG(sContentCacheLog, LogLevel::Error,
+            ("0x%p HandleQueryContentEvent(), FAILED due to query with XP "
+             "linebreaks",
+             this));
+    return false;
+  }
+
+  if (NS_WARN_IF(!aEvent.mInput.IsValidOffset())) {
+    MOZ_LOG(
+        sContentCacheLog, LogLevel::Error,
+        ("0x%p HandleQueryContentEvent(), FAILED due to invalid offset", this));
+    return false;
+  }
+
+  if (NS_WARN_IF(!aEvent.mInput.IsValidEventMessage(aEvent.mMessage))) {
+    MOZ_LOG(
+        sContentCacheLog, LogLevel::Error,
+        ("0x%p HandleQueryContentEvent(), FAILED due to invalid event message",
+         this));
+    return false;
+  }
+
+  bool isRelativeToInsertionPoint = aEvent.mInput.mRelativeToInsertionPoint;
+  if (isRelativeToInsertionPoint) {
+    MOZ_LOG(
+        sContentCacheLog, LogLevel::Debug,
+        ("0x%p HandleQueryContentEvent(), "
+         "making offset absolute... aEvent={ mMessage=%s, mInput={ "
+         "mOffset=%" PRId64 ", mLength=%" PRIu32 " } }, "
+         "WidgetHasComposition()=%s, HasPendingCommit()=%s, "
+         "mCompositionStart=%" PRIu32 ", "
+         "mPendingCommitLength=%" PRIu32 ", mSelection=%s",
+         this, ToChar(aEvent.mMessage), aEvent.mInput.mOffset,
+         aEvent.mInput.mLength, GetBoolName(WidgetHasComposition()),
+         GetBoolName(HasPendingCommit()), mCompositionStart.valueOr(UINT32_MAX),
+         mPendingCommitLength, ToString(mSelection).c_str()));
+    if (WidgetHasComposition() || HasPendingCommit()) {
+      if (NS_WARN_IF(mCompositionStart.isNothing()) ||
+          NS_WARN_IF(!aEvent.mInput.MakeOffsetAbsolute(
+              mCompositionStart.value() + mPendingCommitLength))) {
+        MOZ_LOG(
+            sContentCacheLog, LogLevel::Error,
+            ("0x%p HandleQueryContentEvent(), FAILED due to "
+             "aEvent.mInput.MakeOffsetAbsolute(mCompositionStart + "
+             "mPendingCommitLength) failure, "
+             "mCompositionStart=%" PRIu32 ", mPendingCommitLength=%" PRIu32 ", "
+             "aEvent={ mMessage=%s, mInput={ mOffset=%" PRId64
+             ", mLength=%" PRIu32 " } }",
+             this, mCompositionStart.valueOr(UINT32_MAX), mPendingCommitLength,
+             ToChar(aEvent.mMessage), aEvent.mInput.mOffset,
+             aEvent.mInput.mLength));
+        return false;
+      }
+    } else if (NS_WARN_IF(mSelection.isNothing())) {
+      MOZ_LOG(sContentCacheLog, LogLevel::Error,
+              ("0x%p HandleQueryContentEvent(), FAILED due to mSelection is "
+               "Nothing",
+               this));
+      return false;
+    } else if (NS_WARN_IF(mSelection->mHasRange)) {
+      MOZ_LOG(sContentCacheLog, LogLevel::Error,
+              ("0x%p HandleQueryContentEvent(), FAILED due to there is no "
+               "selection range, but the query requested with relative offset "
+               "from selection",
+               this));
+      return false;
+    } else if (NS_WARN_IF(!aEvent.mInput.MakeOffsetAbsolute(
+                   mSelection->StartOffset() + mPendingCommitLength))) {
+      MOZ_LOG(sContentCacheLog, LogLevel::Error,
+              ("0x%p HandleQueryContentEvent(), FAILED due to "
+               "aEvent.mInput.MakeOffsetAbsolute(mSelection->StartOffset() + "
+               "mPendingCommitLength) failure, mSelection=%s, "
+               "mPendingCommitLength=%" PRIu32 ", aEvent={ mMessage=%s, "
+               "mInput={ mOffset=%" PRId64 ", mLength=%" PRIu32 " } }",
+               this, ToString(mSelection).c_str(), mPendingCommitLength,
+               ToChar(aEvent.mMessage), aEvent.mInput.mOffset,
+               aEvent.mInput.mLength));
+      return false;
+    }
+  }
+
+  switch (aEvent.mMessage) {
+    case eQuerySelectedText:
+      MOZ_LOG(sContentCacheLog, LogLevel::Info,
+              ("0x%p HandleQueryContentEvent(aEvent={ "
+               "mMessage=eQuerySelectedText }, aWidget=0x%p)",
+               this, aWidget));
+      if (MOZ_UNLIKELY(NS_WARN_IF(mSelection.isNothing()))) {
+        // If content cache hasn't been initialized properly, make the query
+        // failed.
+        MOZ_LOG(sContentCacheLog, LogLevel::Error,
+                ("0x%p   HandleQueryContentEvent(), FAILED because mSelection "
+                 "is Nothing",
+                 this));
+        return false;
+      }
+      MOZ_DIAGNOSTIC_ASSERT(mText.isSome());
+      MOZ_DIAGNOSTIC_ASSERT(mSelection->IsValidIn(*mText));
+      aEvent.EmplaceReply();
+      aEvent.mReply->mFocusedWidget = aWidget;
+      if (mSelection->mHasRange) {
+        if (MOZ_LIKELY(mText.isSome())) {
+          aEvent.mReply->mOffsetAndData.emplace(
+              mSelection->StartOffset(),
+              Substring(mText.ref(), mSelection->StartOffset(),
+                        mSelection->Length()),
+              OffsetAndDataFor::SelectedString);
+        } else {
+          // TODO: Investigate this case.  I find this during
+          //       test_mousecapture.xhtml on Linux.
+          aEvent.mReply->mOffsetAndData.emplace(
+              0u, EmptyString(), OffsetAndDataFor::SelectedString);
+        }
+      }
+      aEvent.mReply->mWritingMode = mSelection->mWritingMode;
+      MOZ_LOG(sContentCacheLog, LogLevel::Info,
+              ("0x%p   HandleQueryContentEvent(), Succeeded, aEvent={ "
+               "mMessage=eQuerySelectedText, mReply=%s }",
+               this, ToString(aEvent.mReply).c_str()));
+      return true;
+    case eQueryTextContent: {
+      MOZ_LOG(sContentCacheLog, LogLevel::Info,
+              ("0x%p HandleQueryContentEvent(aEvent={ "
+               "mMessage=eQueryTextContent, mInput={ mOffset=%" PRId64
+               ", mLength=%u } }, aWidget=0x%p), mText->Length()=%zu",
+               this, aEvent.mInput.mOffset, aEvent.mInput.mLength, aWidget,
+               mText.isSome() ? mText->Length() : 0u));
+      if (MOZ_UNLIKELY(NS_WARN_IF(mText.isNothing()))) {
+        MOZ_LOG(sContentCacheLog, LogLevel::Error,
+                ("0x%p   HandleQueryContentEvent(), FAILED because "
+                 "there is no text data",
+                 this));
+        return false;
+      }
+      const uint32_t inputOffset = aEvent.mInput.mOffset;
+      const uint32_t inputEndOffset = std::min<uint32_t>(
+          aEvent.mInput.EndOffset(), mText.isSome() ? mText->Length() : 0u);
+      if (MOZ_UNLIKELY(NS_WARN_IF(inputEndOffset < inputOffset))) {
+        MOZ_LOG(sContentCacheLog, LogLevel::Error,
+                ("0x%p   HandleQueryContentEvent(), FAILED because "
+                 "inputOffset=%u is larger than inputEndOffset=%u",
+                 this, inputOffset, inputEndOffset));
+        return false;
+      }
+      aEvent.EmplaceReply();
+      aEvent.mReply->mFocusedWidget = aWidget;
+      const nsAString& textInQueriedRange =
+          inputEndOffset > inputOffset
+              ? static_cast<const nsAString&>(Substring(
+                    mText.ref(), inputOffset, inputEndOffset - inputOffset))
+              : static_cast<const nsAString&>(EmptyString());
+      aEvent.mReply->mOffsetAndData.emplace(inputOffset, textInQueriedRange,
+                                            OffsetAndDataFor::EditorString);
+      // TODO: Support font ranges
+      MOZ_LOG(sContentCacheLog, LogLevel::Info,
+              ("0x%p   HandleQueryContentEvent(), Succeeded, aEvent={ "
+               "mMessage=eQueryTextContent, mReply=%s }",
+               this, ToString(aEvent.mReply).c_str()));
+      return true;
+    }
+    case eQueryTextRect: {
+      MOZ_LOG(sContentCacheLog, LogLevel::Info,
+              ("0x%p HandleQueryContentEvent("
+               "aEvent={ mMessage=eQueryTextRect, mInput={ mOffset=%" PRId64
+               ", mLength=%u } }, aWidget=0x%p), mText->Length()=%zu",
+               this, aEvent.mInput.mOffset, aEvent.mInput.mLength, aWidget,
+               mText.isSome() ? mText->Length() : 0u));
+      // Note that if the query is relative to insertion point, the query was
+      // probably requested by native IME.  In such case, we should return
+      // non-empty rect since returning failure causes IME showing its window
+      // at odd position.
+      LayoutDeviceIntRect textRect;
+      if (aEvent.mInput.mLength) {
+        if (MOZ_UNLIKELY(NS_WARN_IF(
+                !GetUnionTextRects(aEvent.mInput.mOffset, aEvent.mInput.mLength,
+                                   isRelativeToInsertionPoint, textRect)))) {
+          // XXX We don't have cache for this request.
+          MOZ_LOG(sContentCacheLog, LogLevel::Error,
+                  ("0x%p   HandleQueryContentEvent(), FAILED to get union rect",
+                   this));
+          return false;
+        }
+      } else {
+        // If the length is 0, we should return caret rect instead.
+        if (NS_WARN_IF(!GetCaretRect(aEvent.mInput.mOffset,
+                                     isRelativeToInsertionPoint, textRect))) {
+          MOZ_LOG(sContentCacheLog, LogLevel::Error,
+                  ("0x%p   HandleQueryContentEvent(), FAILED to get caret rect",
+                   this));
+          return false;
+        }
+      }
+      aEvent.EmplaceReply();
+      aEvent.mReply->mFocusedWidget = aWidget;
+      aEvent.mReply->mRect = textRect;
+      const nsAString& textInQueriedRange =
+          mText.isSome() && aEvent.mInput.mOffset <
+                                static_cast<int64_t>(
+                                    mText.isSome() ? mText->Length() : 0u)
+              ? static_cast<const nsAString&>(
+                    Substring(mText.ref(), aEvent.mInput.mOffset,
+                              mText->Length() >= aEvent.mInput.EndOffset()
+                                  ? aEvent.mInput.mLength
+                                  : UINT32_MAX))
+              : static_cast<const nsAString&>(EmptyString());
+      aEvent.mReply->mOffsetAndData.emplace(aEvent.mInput.mOffset,
+                                            textInQueriedRange,
+                                            OffsetAndDataFor::EditorString);
+      // XXX This may be wrong if storing range isn't in the selection range.
+      aEvent.mReply->mWritingMode =
+          mSelection.isSome() ? mSelection->mWritingMode : WritingMode();
+      MOZ_LOG(sContentCacheLog, LogLevel::Info,
+              ("0x%p   HandleQueryContentEvent(), Succeeded, aEvent={ "
+               "mMessage=eQueryTextRect mReply=%s }",
+               this, ToString(aEvent.mReply).c_str()));
+      return true;
+    }
+    case eQueryCaretRect: {
+      MOZ_LOG(
+          sContentCacheLog, LogLevel::Info,
+          ("0x%p HandleQueryContentEvent(aEvent={ mMessage=eQueryCaretRect, "
+           "mInput={ mOffset=%" PRId64
+           " } }, aWidget=0x%p), mText->Length()=%zu",
+           this, aEvent.mInput.mOffset, aWidget,
+           mText.isSome() ? mText->Length() : 0u));
+      // Note that if the query is relative to insertion point, the query was
+      // probably requested by native IME.  In such case, we should return
+      // non-empty rect since returning failure causes IME showing its window
+      // at odd position.
+      LayoutDeviceIntRect caretRect;
+      if (NS_WARN_IF(!GetCaretRect(aEvent.mInput.mOffset,
+                                   isRelativeToInsertionPoint, caretRect))) {
+        MOZ_LOG(sContentCacheLog, LogLevel::Error,
+                ("0x%p   HandleQueryContentEvent(),FAILED to get caret rect",
+                 this));
+        return false;
+      }
+      aEvent.EmplaceReply();
+      aEvent.mReply->mFocusedWidget = aWidget;
+      aEvent.mReply->mRect = caretRect;
+      aEvent.mReply->mOffsetAndData.emplace(aEvent.mInput.mOffset,
+                                            EmptyString(),
+                                            OffsetAndDataFor::SelectedString);
+      // TODO: Set mWritingMode here
+      MOZ_LOG(sContentCacheLog, LogLevel::Info,
+              ("0x%p   HandleQueryContentEvent(), Succeeded, aEvent={ "
+               "mMessage=eQueryCaretRect, mReply=%s }",
+               this, ToString(aEvent.mReply).c_str()));
+      return true;
+    }
+    case eQueryEditorRect:
+      MOZ_LOG(sContentCacheLog, LogLevel::Info,
+              ("0x%p HandleQueryContentEvent(aEvent={ "
+               "mMessage=eQueryEditorRect }, aWidget=0x%p)",
+               this, aWidget));
+      // XXX This query should fail if no editable elmenet has focus.  Or,
+      //     perhaps, should return rect of the window instead.
+      aEvent.EmplaceReply();
+      aEvent.mReply->mFocusedWidget = aWidget;
+      aEvent.mReply->mRect = mEditorRect;
+      MOZ_LOG(sContentCacheLog, LogLevel::Info,
+              ("0x%p   HandleQueryContentEvent(), Succeeded, aEvent={ "
+               "mMessage=eQueryEditorRect, mReply=%s }",
+               this, ToString(aEvent.mReply).c_str()));
+      return true;
+    default:
+      aEvent.EmplaceReply();
+      aEvent.mReply->mFocusedWidget = aWidget;
+      if (NS_WARN_IF(aEvent.Failed())) {
+        MOZ_LOG(
+            sContentCacheLog, LogLevel::Error,
+            ("0x%p HandleQueryContentEvent(), FAILED due to not set enough "
+             "data, aEvent={ mMessage=%s, mReply=%s }",
+             this, ToChar(aEvent.mMessage), ToString(aEvent.mReply).c_str()));
+        return false;
+      }
+      MOZ_LOG(sContentCacheLog, LogLevel::Info,
+              ("0x%p HandleQueryContentEvent(), Succeeded, aEvent={ "
+               "mMessage=%s, mReply=%s }",
+               this, ToChar(aEvent.mMessage), ToString(aEvent.mReply).c_str()));
+      return true;
+  }
+}
+
+bool ContentCacheInParent::GetTextRect(uint32_t aOffset,
+                                       bool aRoundToExistingOffset,
+                                       LayoutDeviceIntRect& aTextRect) const {
+  MOZ_LOG(
+      sContentCacheLog, LogLevel::Info,
+      ("0x%p GetTextRect(aOffset=%u, aRoundToExistingOffset=%s), "
+       "mTextRectArray=%s, mSelection=%s, mLastCommitStringTextRectArray=%s",
+       this, aOffset, GetBoolName(aRoundToExistingOffset),
+       ToString(mTextRectArray).c_str(), ToString(mSelection).c_str(),
+       ToString(mLastCommitStringTextRectArray).c_str()));
+
+  if (!aOffset) {
+    NS_WARNING_ASSERTION(!mFirstCharRect.IsEmpty(), "empty rect");
+    aTextRect = mFirstCharRect;
+    return !aTextRect.IsEmpty();
+  }
+  if (mSelection.isSome() && mSelection->mHasRange) {
+    if (aOffset == mSelection->mAnchor) {
+      NS_WARNING_ASSERTION(
+          !mSelection->mAnchorCharRects[eNextCharRect].IsEmpty(), "empty rect");
+      aTextRect = mSelection->mAnchorCharRects[eNextCharRect];
+      return !aTextRect.IsEmpty();
+    }
+    if (mSelection->mAnchor && aOffset == mSelection->mAnchor - 1) {
+      NS_WARNING_ASSERTION(
+          !mSelection->mAnchorCharRects[ePrevCharRect].IsEmpty(), "empty rect");
+      aTextRect = mSelection->mAnchorCharRects[ePrevCharRect];
+      return !aTextRect.IsEmpty();
+    }
+    if (aOffset == mSelection->mFocus) {
+      NS_WARNING_ASSERTION(
+          !mSelection->mFocusCharRects[eNextCharRect].IsEmpty(), "empty rect");
+      aTextRect = mSelection->mFocusCharRects[eNextCharRect];
+      return !aTextRect.IsEmpty();
+    }
+    if (mSelection->mFocus && aOffset == mSelection->mFocus - 1) {
+      NS_WARNING_ASSERTION(
+          !mSelection->mFocusCharRects[ePrevCharRect].IsEmpty(), "empty rect");
+      aTextRect = mSelection->mFocusCharRects[ePrevCharRect];
+      return !aTextRect.IsEmpty();
+    }
+  }
+
+  if (mTextRectArray.isSome() && mTextRectArray->IsOffsetInRange(aOffset)) {
+    aTextRect = mTextRectArray->GetRect(aOffset);
+    return !aTextRect.IsEmpty();
+  }
+
+  if (mLastCommitStringTextRectArray.isSome() &&
+      mLastCommitStringTextRectArray->IsOffsetInRange(aOffset)) {
+    aTextRect = mLastCommitStringTextRectArray->GetRect(aOffset);
+    return !aTextRect.IsEmpty();
+  }
+
+  if (!aRoundToExistingOffset) {
+    aTextRect.SetEmpty();
+    return false;
+  }
+
+  if (mTextRectArray.isNothing() || !mTextRectArray->HasRects()) {
+    // If there are no rects in mTextRectArray, we should refer the start of
+    // the selection if there is because IME must query a char rect around it if
+    // there is no composition.
+    if (mSelection.isNothing()) {
+      // Unfortunately, there is no data about text rect...
+      aTextRect.SetEmpty();
+      return false;
+    }
+    aTextRect = mSelection->StartCharRect();
+    return !aTextRect.IsEmpty();
+  }
+
+  // Although we may have mLastCommitStringTextRectArray here and it must have
+  // previous character rects at selection.  However, we should stop using it
+  // because it's stored really short time after commiting a composition.
+  // So, multiple query may return different rect and it may cause flickerling
+  // the IME UI.
+  uint32_t offset = aOffset;
+  if (offset < mTextRectArray->StartOffset()) {
+    offset = mTextRectArray->StartOffset();
+  } else {
+    offset = mTextRectArray->EndOffset() - 1;
+  }
+  aTextRect = mTextRectArray->GetRect(offset);
+  return !aTextRect.IsEmpty();
+}
+
+bool ContentCacheInParent::GetUnionTextRects(
+    uint32_t aOffset, uint32_t aLength, bool aRoundToExistingOffset,
+    LayoutDeviceIntRect& aUnionTextRect) const {
+  MOZ_LOG(sContentCacheLog, LogLevel::Info,
+          ("0x%p GetUnionTextRects(aOffset=%u, "
+           "aLength=%u, aRoundToExistingOffset=%s), mTextRectArray=%s, "
+           "mSelection=%s, mLastCommitStringTextRectArray=%s",
+           this, aOffset, aLength, GetBoolName(aRoundToExistingOffset),
+           ToString(mTextRectArray).c_str(), ToString(mSelection).c_str(),
+           ToString(mLastCommitStringTextRectArray).c_str()));
+
+  CheckedInt<uint32_t> endOffset = CheckedInt<uint32_t>(aOffset) + aLength;
+  if (!endOffset.isValid()) {
+    return false;
+  }
+
+  if (mSelection.isSome() && !mSelection->IsCollapsed() &&
+      aOffset == mSelection->StartOffset() && aLength == mSelection->Length()) {
+    NS_WARNING_ASSERTION(!mSelection->mRect.IsEmpty(), "empty rect");
+    aUnionTextRect = mSelection->mRect;
+    return !aUnionTextRect.IsEmpty();
+  }
+
+  if (aLength == 1) {
+    if (!aOffset) {
+      NS_WARNING_ASSERTION(!mFirstCharRect.IsEmpty(), "empty rect");
+      aUnionTextRect = mFirstCharRect;
+      return !aUnionTextRect.IsEmpty();
+    }
+    if (mSelection.isSome() && mSelection->mHasRange) {
+      if (aOffset == mSelection->mAnchor) {
+        NS_WARNING_ASSERTION(
+            !mSelection->mAnchorCharRects[eNextCharRect].IsEmpty(),
+            "empty rect");
+        aUnionTextRect = mSelection->mAnchorCharRects[eNextCharRect];
+        return !aUnionTextRect.IsEmpty();
+      }
+      if (mSelection->mAnchor && aOffset == mSelection->mAnchor - 1) {
+        NS_WARNING_ASSERTION(
+            !mSelection->mAnchorCharRects[ePrevCharRect].IsEmpty(),
+            "empty rect");
+        aUnionTextRect = mSelection->mAnchorCharRects[ePrevCharRect];
+        return !aUnionTextRect.IsEmpty();
+      }
+      if (aOffset == mSelection->mFocus) {
+        NS_WARNING_ASSERTION(
+            !mSelection->mFocusCharRects[eNextCharRect].IsEmpty(),
+            "empty rect");
+        aUnionTextRect = mSelection->mFocusCharRects[eNextCharRect];
+        return !aUnionTextRect.IsEmpty();
+      }
+      if (mSelection->mFocus && aOffset == mSelection->mFocus - 1) {
+        NS_WARNING_ASSERTION(
+            !mSelection->mFocusCharRects[ePrevCharRect].IsEmpty(),
+            "empty rect");
+        aUnionTextRect = mSelection->mFocusCharRects[ePrevCharRect];
+        return !aUnionTextRect.IsEmpty();
+      }
+    }
+  }
+
+  // Even if some text rects are not cached of the queried range,
+  // we should return union rect when the first character's rect is cached
+  // since the first character rect is important and the others are not so
+  // in most cases.
+
+  if (!aOffset && mSelection.isSome() && mSelection->mHasRange &&
+      aOffset != mSelection->mAnchor && aOffset != mSelection->mFocus &&
+      (mTextRectArray.isNothing() ||
+       !mTextRectArray->IsOffsetInRange(aOffset)) &&
+      (mLastCommitStringTextRectArray.isNothing() ||
+       !mLastCommitStringTextRectArray->IsOffsetInRange(aOffset))) {
+    // The first character rect isn't cached.
+    return false;
+  }
+
+  // Use mLastCommitStringTextRectArray only when it overlaps with aOffset
+  // even if aROundToExistingOffset is true for avoiding flickerling IME UI.
+  // See the last comment in GetTextRect() for the detail.
+  if (mLastCommitStringTextRectArray.isSome() &&
+      mLastCommitStringTextRectArray->IsOverlappingWith(aOffset, aLength)) {
+    aUnionTextRect =
+        mLastCommitStringTextRectArray->GetUnionRectAsFarAsPossible(
+            aOffset, aLength, aRoundToExistingOffset);
+  } else {
+    aUnionTextRect.SetEmpty();
+  }
+
+  if (mTextRectArray.isSome() &&
+      ((aRoundToExistingOffset && mTextRectArray->HasRects()) ||
+       mTextRectArray->IsOverlappingWith(aOffset, aLength))) {
+    aUnionTextRect =
+        aUnionTextRect.Union(mTextRectArray->GetUnionRectAsFarAsPossible(
+            aOffset, aLength, aRoundToExistingOffset));
+  }
+
+  if (!aOffset) {
+    aUnionTextRect = aUnionTextRect.Union(mFirstCharRect);
+  }
+  if (mSelection.isSome() && mSelection->mHasRange) {
+    if (aOffset <= mSelection->mAnchor &&
+        mSelection->mAnchor < endOffset.value()) {
+      aUnionTextRect =
+          aUnionTextRect.Union(mSelection->mAnchorCharRects[eNextCharRect]);
+    }
+    if (mSelection->mAnchor && aOffset <= mSelection->mAnchor - 1 &&
+        mSelection->mAnchor - 1 < endOffset.value()) {
+      aUnionTextRect =
+          aUnionTextRect.Union(mSelection->mAnchorCharRects[ePrevCharRect]);
+    }
+    if (aOffset <= mSelection->mFocus &&
+        mSelection->mFocus < endOffset.value()) {
+      aUnionTextRect =
+          aUnionTextRect.Union(mSelection->mFocusCharRects[eNextCharRect]);
+    }
+    if (mSelection->mFocus && aOffset <= mSelection->mFocus - 1 &&
+        mSelection->mFocus - 1 < endOffset.value()) {
+      aUnionTextRect =
+          aUnionTextRect.Union(mSelection->mFocusCharRects[ePrevCharRect]);
+    }
+  }
+
+  return !aUnionTextRect.IsEmpty();
+}
+
+bool ContentCacheInParent::GetCaretRect(uint32_t aOffset,
+                                        bool aRoundToExistingOffset,
+                                        LayoutDeviceIntRect& aCaretRect) const {
+  MOZ_LOG(sContentCacheLog, LogLevel::Info,
+          ("0x%p GetCaretRect(aOffset=%u, aRoundToExistingOffset=%s), "
+           "mCaret=%s, mTextRectArray=%s, mSelection=%s, mFirstCharRect=%s",
+           this, aOffset, GetBoolName(aRoundToExistingOffset),
+           ToString(mCaret).c_str(), ToString(mTextRectArray).c_str(),
+           ToString(mSelection).c_str(), ToString(mFirstCharRect).c_str()));
+
+  if (mCaret.isSome() && mCaret->mOffset == aOffset) {
+    aCaretRect = mCaret->mRect;
+    return true;
+  }
+
+  // Guess caret rect from the text rect if it's stored.
+  if (!GetTextRect(aOffset, aRoundToExistingOffset, aCaretRect)) {
+    // There might be previous character rect in the cache.  If so, we can
+    // guess the caret rect with it.
+    if (!aOffset ||
+        !GetTextRect(aOffset - 1, aRoundToExistingOffset, aCaretRect)) {
+      aCaretRect.SetEmpty();
+      return false;
+    }
+
+    if (mSelection.isSome() && mSelection->mWritingMode.IsVertical()) {
+      aCaretRect.MoveToY(aCaretRect.YMost());
+    } else {
+      // XXX bidi-unaware.
+      aCaretRect.MoveToX(aCaretRect.XMost());
+    }
+  }
+
+  // XXX This is not bidi aware because we don't cache each character's
+  //     direction.  However, this is usually used by IME, so, assuming the
+  //     character is in LRT context must not cause any problem.
+  if (mSelection.isSome() && mSelection->mWritingMode.IsVertical()) {
+    aCaretRect.SetHeight(mCaret.isSome() ? mCaret->mRect.Height() : 1);
+  } else {
+    aCaretRect.SetWidth(mCaret.isSome() ? mCaret->mRect.Width() : 1);
+  }
+  return true;
+}
+
+bool ContentCacheInParent::OnCompositionEvent(
+    const WidgetCompositionEvent& aCompositionEvent) {
+  MOZ_LOG(
+      sContentCacheLog, LogLevel::Info,
+      ("0x%p OnCompositionEvent(aCompositionEvent={ "
+       "mMessage=%s, mData=\"%s\", mRanges->Length()=%zu }), "
+       "PendingEventsNeedingAck()=%u, WidgetHasComposition()=%s, "
+       "mHandlingCompositions.Length()=%zu, HasPendingCommit()=%s, "
+       "mIsChildIgnoringCompositionEvents=%s, mCommitStringByRequest=0x%p",
+       this, ToChar(aCompositionEvent.mMessage),
+       PrintStringDetail(aCompositionEvent.mData,
+                         PrintStringDetail::kMaxLengthForCompositionString)
+           .get(),
+       aCompositionEvent.mRanges ? aCompositionEvent.mRanges->Length() : 0,
+       PendingEventsNeedingAck(), GetBoolName(WidgetHasComposition()),
+       mHandlingCompositions.Length(), GetBoolName(HasPendingCommit()),
+       GetBoolName(mIsChildIgnoringCompositionEvents), mCommitStringByRequest));
+
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  mDispatchedEventMessages.AppendElement(aCompositionEvent.mMessage);
+#endif  // #ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+
+  // We must be able to simulate the selection because
+  // we might not receive selection updates in time
+  if (!WidgetHasComposition()) {
+    if (mCompositionStartInChild.isSome()) {
+      // If there is pending composition in the remote process, let's use
+      // its start offset temporarily because this stores a lot of information
+      // around it and the user must look around there, so, showing some UI
+      // around it must make sense.
+      mCompositionStart = mCompositionStartInChild;
+    } else {
+      mCompositionStart = Some(mSelection.isSome() && mSelection->mHasRange
+                                   ? mSelection->StartOffset()
+                                   : 0u);
+    }
+    MOZ_ASSERT(aCompositionEvent.mMessage == eCompositionStart);
+    mHandlingCompositions.AppendElement(
+        HandlingCompositionData(aCompositionEvent.mCompositionId));
+  }
+
+  mHandlingCompositions.LastElement().mSentCommitEvent =
+      aCompositionEvent.CausesDOMCompositionEndEvent();
+  MOZ_ASSERT(mHandlingCompositions.LastElement().mCompositionId ==
+             aCompositionEvent.mCompositionId);
+
+  if (!WidgetHasComposition()) {
+    // mCompositionStart will be reset when commit event is completely handled
+    // in the remote process.
+    if (mHandlingCompositions.Length() == 1u) {
+      mPendingCommitLength = aCompositionEvent.mData.Length();
+    }
+    MOZ_ASSERT(HasPendingCommit());
+  } else if (aCompositionEvent.mMessage != eCompositionStart) {
+    mHandlingCompositions.LastElement().mCompositionString =
+        aCompositionEvent.mData;
+  }
+
+  // During REQUEST_TO_COMMIT_COMPOSITION or REQUEST_TO_CANCEL_COMPOSITION,
+  // widget usually sends a eCompositionChange and/or eCompositionCommit event
+  // to finalize or clear the composition, respectively.  In this time,
+  // we need to intercept all composition events here and pass the commit
+  // string for returning to the remote process as a result of
+  // RequestIMEToCommitComposition().  Then, eCommitComposition event will
+  // be dispatched with the committed string in the remote process internally.
+  if (mCommitStringByRequest) {
+    if (aCompositionEvent.mMessage == eCompositionCommitAsIs) {
+      *mCommitStringByRequest =
+          mHandlingCompositions.LastElement().mCompositionString;
+    } else {
+      MOZ_ASSERT(aCompositionEvent.mMessage == eCompositionChange ||
+                 aCompositionEvent.mMessage == eCompositionCommit);
+      *mCommitStringByRequest = aCompositionEvent.mData;
+    }
+    // We need to wait eCompositionCommitRequestHandled from the remote process
+    // in this case.  Therefore, mPendingEventsNeedingAck needs to be
+    // incremented here.
+    if (!WidgetHasComposition()) {
+      mHandlingCompositions.LastElement().mPendingEventsNeedingAck++;
+    }
+    return false;
+  }
+
+  mHandlingCompositions.LastElement().mPendingEventsNeedingAck++;
+  return true;
+}
+
+void ContentCacheInParent::OnSelectionEvent(
+    const WidgetSelectionEvent& aSelectionEvent) {
+  MOZ_LOG(sContentCacheLog, LogLevel::Info,
+          ("0x%p OnSelectionEvent(aEvent={ "
+           "mMessage=%s, mOffset=%u, mLength=%u, mReversed=%s, "
+           "mExpandToClusterBoundary=%s, mUseNativeLineBreak=%s }), "
+           "PendingEventsNeedingAck()=%u, WidgetHasComposition()=%s, "
+           "mHandlingCompositions.Length()=%zu, HasPendingCommit()=%s, "
+           "mIsChildIgnoringCompositionEvents=%s",
+           this, ToChar(aSelectionEvent.mMessage), aSelectionEvent.mOffset,
+           aSelectionEvent.mLength, GetBoolName(aSelectionEvent.mReversed),
+           GetBoolName(aSelectionEvent.mExpandToClusterBoundary),
+           GetBoolName(aSelectionEvent.mUseNativeLineBreak),
+           PendingEventsNeedingAck(), GetBoolName(WidgetHasComposition()),
+           mHandlingCompositions.Length(), GetBoolName(HasPendingCommit()),
+           GetBoolName(mIsChildIgnoringCompositionEvents)));
+
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED && !defined(FUZZING_SNAPSHOT)
+  mDispatchedEventMessages.AppendElement(aSelectionEvent.mMessage);
+#endif  // MOZ_DIAGNOSTIC_ASSERT_ENABLED
+
+  mPendingSetSelectionEventNeedingAck++;
+}
+
+void ContentCacheInParent::OnEventNeedingAckHandled(nsIWidget* aWidget,
+                                                    EventMessage aMessage,
+                                                    uint32_t aCompositionId) {
+  // This is called when the child process receives WidgetCompositionEvent or
+  // WidgetSelectionEvent.
+
+  HandlingCompositionData* handlingCompositionData =
+      aMessage != eSetSelection ? GetHandlingCompositionData(aCompositionId)
+                                : nullptr;
+
+  MOZ_LOG(sContentCacheLog, LogLevel::Info,
+          ("0x%p OnEventNeedingAckHandled(aWidget=0x%p, aMessage=%s, "
+           "aCompositionId=%" PRIu32
+           "), PendingEventsNeedingAck()=%u, WidgetHasComposition()=%s, "
+           "mHandlingCompositions.Length()=%zu, HasPendingCommit()=%s, "
+           "mIsChildIgnoringCompositionEvents=%s, handlingCompositionData=0x%p",
+           this, aWidget, ToChar(aMessage), aCompositionId,
+           PendingEventsNeedingAck(), GetBoolName(WidgetHasComposition()),
+           mHandlingCompositions.Length(), GetBoolName(HasPendingCommit()),
+           GetBoolName(mIsChildIgnoringCompositionEvents),
+           handlingCompositionData));
+
+  // If we receive composition event messages for older one or invalid one,
+  // we should ignore them.
+  if (NS_WARN_IF(aMessage != eSetSelection && !handlingCompositionData)) {
+    return;
+  }
+
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED && !defined(FUZZING_SNAPSHOT)
+  mReceivedEventMessages.AppendElement(aMessage);
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+
+  const bool isCommittedInChild =
+      // Commit requester in the remote process has committed the composition.
+      aMessage == eCompositionCommitRequestHandled ||
+      // The commit event has been handled normally in the remote process.
+      (!mIsChildIgnoringCompositionEvents &&
+       WidgetCompositionEvent::IsFollowedByCompositionEnd(aMessage));
+  const bool hasPendingCommit = HasPendingCommit();
+
+  if (isCommittedInChild) {
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED && !defined(FUZZING_SNAPSHOT)
+    if (mHandlingCompositions.Length() == 1u) {
+      RemoveUnnecessaryEventMessageLog();
+    }
+
+    if (NS_WARN_IF(aMessage != eCompositionCommitRequestHandled &&
+                   !handlingCompositionData->mSentCommitEvent)) {
+      nsPrintfCString info(
+          "\nReceived unexpected commit event message (%s) which we've "
+          "not sent yet\n\n",
+          ToChar(aMessage));
+      AppendEventMessageLog(info);
+      CrashReporter::AppendAppNotesToCrashReport(info);
+      MOZ_DIAGNOSTIC_ASSERT(
+          false,
+          "Received unexpected commit event which has not been sent yet");
+    }
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+
+    // This should not occur, though.  If we receive a commit notification for
+    // not the oldest composition, we should forget all older compositions.
+    size_t numberOfOutdatedCompositions = 1u;
+    for (auto& data : mHandlingCompositions) {
+      if (&data == handlingCompositionData) {
+        if (
+            // Don't put the info into the log when we've already sent commit
+            // event because it may be just inserting a character without
+            // composing state, but the remote process may move focus at
+            // eCompositionStart.  This may happen with UI of IME to put only
+            // one character, e.g., the default Emoji picker of Windows.
+            !data.mSentCommitEvent &&
+            // In the normal case, only one message should remain, however,
+            // remaining 2 or more messages is also valid, for example, the
+            // remote process may have a composition update listener which
+            // takes a while.  Then, we can have multiple pending messages.
+            data.mPendingEventsNeedingAck >= 1u) {
+          MOZ_LOG(
+              sContentCacheLog, LogLevel::Debug,
+              ("    NOTE: BrowserParent has %" PRIu32
+               " pending composition messages for the handling composition, "
+               "but before they are handled in the remote process, the active "
+               "composition is commited by a request.  "
+               "OnEventNeedingAckHandled() calls for them will be ignored",
+               data.mPendingEventsNeedingAck));
+        }
+        break;
+      }
+      if (MOZ_UNLIKELY(data.mPendingEventsNeedingAck)) {
+        MOZ_LOG(sContentCacheLog, LogLevel::Warning,
+                ("    BrowserParent has %" PRIu32
+                 " pending composition messages for an older composition than "
+                 "the handling composition, but it'll be removed because newer "
+                 "composition gets comitted in the remote process",
+                 data.mPendingEventsNeedingAck));
+      }
+      numberOfOutdatedCompositions++;
+    }
+    mHandlingCompositions.RemoveElementsAt(0u, numberOfOutdatedCompositions);
+    handlingCompositionData = nullptr;
+
+    // Forget pending commit string length if it's handled in the remote
+    // process.  Note that this doesn't care too old composition's commit
+    // string because in such case, we cannot return proper information
+    // to IME synchronously.
+    mPendingCommitLength = 0;
+  }
+
+  if (WidgetCompositionEvent::IsFollowedByCompositionEnd(aMessage)) {
+    // After the remote process receives eCompositionCommit(AsIs) event,
+    // it'll restart to handle composition events.
+    mIsChildIgnoringCompositionEvents = false;
+
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED && !defined(FUZZING_SNAPSHOT)
+    if (NS_WARN_IF(!hasPendingCommit)) {
+      nsPrintfCString info(
+          "\nThere is no pending comment events but received "
+          "%s message from the remote child\n\n",
+          ToChar(aMessage));
+      AppendEventMessageLog(info);
+      CrashReporter::AppendAppNotesToCrashReport(info);
+      MOZ_DIAGNOSTIC_ASSERT(
+          false,
+          "No pending commit events but received unexpected commit event");
+    }
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  } else if (aMessage == eCompositionCommitRequestHandled && hasPendingCommit) {
+    // If the remote process commits composition synchronously after
+    // requesting commit composition and we've already sent commit composition,
+    // it starts to ignore following composition events until receiving
+    // eCompositionStart event.
+    mIsChildIgnoringCompositionEvents = true;
+  }
+
+  // If neither widget (i.e., IME) nor the remote process has composition,
+  // now, we can forget composition string informations.
+  if (mHandlingCompositions.IsEmpty()) {
+    mCompositionStart.reset();
+  }
+
+  if (handlingCompositionData) {
+    if (NS_WARN_IF(!handlingCompositionData->mPendingEventsNeedingAck)) {
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED && !defined(FUZZING_SNAPSHOT)
+      nsPrintfCString info(
+          "\nThere is no pending events but received %s "
+          "message from the remote child\n\n",
+          ToChar(aMessage));
+      AppendEventMessageLog(info);
+      CrashReporter::AppendAppNotesToCrashReport(info);
+      MOZ_DIAGNOSTIC_ASSERT(
+          false, "No pending event message but received unexpected event");
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    } else {
+      handlingCompositionData->mPendingEventsNeedingAck--;
+    }
+  } else if (aMessage == eSetSelection) {
+    if (NS_WARN_IF(!mPendingSetSelectionEventNeedingAck)) {
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED && !defined(FUZZING_SNAPSHOT)
+      nsAutoCString info(
+          "\nThere is no pending set selection events but received from the "
+          "remote child\n\n");
+      AppendEventMessageLog(info);
+      CrashReporter::AppendAppNotesToCrashReport(info);
+      MOZ_DIAGNOSTIC_ASSERT(
+          false, "No pending event message but received unexpected event");
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    } else {
+      mPendingSetSelectionEventNeedingAck--;
+    }
+  }
+
+  if (!PendingEventsNeedingAck()) {
+    FlushPendingNotifications(aWidget);
+  }
+}
+
+bool ContentCacheInParent::RequestIMEToCommitComposition(
+    nsIWidget* aWidget, bool aCancel, uint32_t aCompositionId,
+    nsAString& aCommittedString) {
+  HandlingCompositionData* const handlingCompositionData =
+      GetHandlingCompositionData(aCompositionId);
+
+  MOZ_LOG(
+      sContentCacheLog, LogLevel::Info,
+      ("0x%p RequestToCommitComposition(aWidget=%p, "
+       "aCancel=%s, aCompositionId=%" PRIu32
+       "), mHandlingCompositions.Length()=%zu, HasPendingCommit()=%s, "
+       "mIsChildIgnoringCompositionEvents=%s, "
+       "IMEStateManager::DoesBrowserParentHaveIMEFocus(&mBrowserParent)=%s, "
+       "WidgetHasComposition()=%s, mCommitStringByRequest=%p, "
+       "handlingCompositionData=0x%p",
+       this, aWidget, GetBoolName(aCancel), aCompositionId,
+       mHandlingCompositions.Length(), GetBoolName(HasPendingCommit()),
+       GetBoolName(mIsChildIgnoringCompositionEvents),
+       GetBoolName(
+           IMEStateManager::DoesBrowserParentHaveIMEFocus(&mBrowserParent)),
+       GetBoolName(WidgetHasComposition()), mCommitStringByRequest,
+       handlingCompositionData));
+
+  MOZ_ASSERT(!mCommitStringByRequest);
+
+  // If we don't know the composition ID, it must have already been committed
+  // in this process.  In the case, we should do nothing here.
+  if (NS_WARN_IF(!handlingCompositionData)) {
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    mRequestIMEToCommitCompositionResults.AppendElement(
+        RequestIMEToCommitCompositionResult::eToUnknownCompositionReceived);
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    return false;
+  }
+
+  // If we receive a commit result for not latest composition, this request is
+  // too late for IME.  The remote process should wait following composition
+  // events for cleaning up TextComposition and handle the request as it's
+  // handled asynchronously.
+  if (handlingCompositionData != &mHandlingCompositions.LastElement()) {
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    mRequestIMEToCommitCompositionResults.AppendElement(
+        RequestIMEToCommitCompositionResult::eToOldCompositionReceived);
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    return false;
+  }
+
+  // If the composition has already been commit, th remote process will receive
+  // composition events and clean up TextComposition.  So, this should do
+  // nothing and TextComposition should handle the request as it's handled
+  // asynchronously.
+  // XXX Perhaps, this is wrong because TextComposition in child process
+  //     may commit the composition with current composition string in the
+  //     remote process.  I.e., it may be different from actual commit string
+  //     which user typed.  So, perhaps, we should return true and the commit
+  //     string.
+  if (handlingCompositionData->mSentCommitEvent) {
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    mRequestIMEToCommitCompositionResults.AppendElement(
+        RequestIMEToCommitCompositionResult::eToCommittedCompositionReceived);
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    return false;
+  }
+
+  // If BrowserParent which has IME focus was already changed to different one,
+  // the request shouldn't be sent to IME because it's too late.
+  if (!IMEStateManager::DoesBrowserParentHaveIMEFocus(&mBrowserParent)) {
+    // Use the latest composition string which may not be handled in the
+    // remote process for avoiding data loss.
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    mRequestIMEToCommitCompositionResults.AppendElement(
+        RequestIMEToCommitCompositionResult::eReceivedAfterBrowserParentBlur);
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    aCommittedString = handlingCompositionData->mCompositionString;
+    // After we return true from here, i.e., without actually requesting IME
+    // to commit composition, we will receive eCompositionCommitRequestHandled
+    // pseudo event message from the remote process.  So, we need to increment
+    // mPendingEventsNeedingAck here.
+    handlingCompositionData->mPendingEventsNeedingAck++;
+    return true;
+  }
+
+  RefPtr<TextComposition> composition =
+      IMEStateManager::GetTextCompositionFor(aWidget);
+  if (NS_WARN_IF(!composition)) {
+    MOZ_LOG(sContentCacheLog, LogLevel::Warning,
+            ("  0x%p RequestToCommitComposition(), "
+             "does nothing due to no composition",
+             this));
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    mRequestIMEToCommitCompositionResults.AppendElement(
+        RequestIMEToCommitCompositionResult::eReceivedButNoTextComposition);
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    return false;
+  }
+
+  // If we receive a request for different composition, we must have already
+  // sent a commit event. So the remote process should handle it.
+  // XXX I think that this should never happen because we already checked
+  // whether handlingCompositionData is the latest composition or not.
+  // However, we don't want to commit different composition for the users.
+  // Therefore, let's handle the odd case here.
+  if (NS_WARN_IF(composition->Id() != aCompositionId)) {
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    mRequestIMEToCommitCompositionResults.AppendElement(
+        RequestIMEToCommitCompositionResult::
+            eReceivedButForDifferentTextComposition);
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    return false;
+  }
+
+  mCommitStringByRequest = &aCommittedString;
+
+  // Request commit or cancel composition with TextComposition because we may
+  // have already requested to commit or cancel the composition or we may
+  // have already received eCompositionCommit(AsIs) event.  Those status are
+  // managed by composition.  So, if we don't request commit composition,
+  // we should do nothing with native IME here.
+  composition->RequestToCommit(aWidget, aCancel);
+
+  mCommitStringByRequest = nullptr;
+
+  MOZ_LOG(
+      sContentCacheLog, LogLevel::Info,
+      ("  0x%p RequestToCommitComposition(), "
+       "WidgetHasComposition()=%s, the composition %s committed synchronously",
+       this, GetBoolName(WidgetHasComposition()),
+       composition->Destroyed() ? "WAS" : "has NOT been"));
+
+  if (!composition->Destroyed()) {
+    // When the composition isn't committed synchronously, the remote process's
+    // TextComposition instance will synthesize commit events and wait to
+    // receive delayed composition events.  When TextComposition instances both
+    // in this process and the remote process will be destroyed when delayed
+    // composition events received. TextComposition instance in the parent
+    // process will dispatch following composition events and be destroyed
+    // normally. On the other hand, TextComposition instance in the remote
+    // process won't dispatch following composition events and will be
+    // destroyed by IMEStateManager::DispatchCompositionEvent().
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    mRequestIMEToCommitCompositionResults.AppendElement(
+        RequestIMEToCommitCompositionResult::eHandledAsynchronously);
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+    return false;
+  }
+
+  // When the composition is committed synchronously, the commit string will be
+  // returned to the remote process.  Then, PuppetWidget will dispatch
+  // eCompositionCommit event with the returned commit string (i.e., the value
+  // is aCommittedString of this method) and that causes destroying
+  // TextComposition instance in the remote process (Note that TextComposition
+  // instance in this process was already destroyed).
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  mRequestIMEToCommitCompositionResults.AppendElement(
+      RequestIMEToCommitCompositionResult::eHandledSynchronously);
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  return true;
+}
+
+void ContentCacheInParent::MaybeNotifyIME(
+    nsIWidget* aWidget, const IMENotification& aNotification) {
+  if (!PendingEventsNeedingAck()) {
+    IMEStateManager::NotifyIME(aNotification, aWidget, &mBrowserParent);
+    return;
+  }
+
+  switch (aNotification.mMessage) {
+    case NOTIFY_IME_OF_SELECTION_CHANGE:
+      mPendingSelectionChange.MergeWith(aNotification);
+      break;
+    case NOTIFY_IME_OF_TEXT_CHANGE:
+      mPendingTextChange.MergeWith(aNotification);
+      break;
+    case NOTIFY_IME_OF_POSITION_CHANGE:
+      mPendingLayoutChange.MergeWith(aNotification);
+      break;
+    case NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED:
+      mPendingCompositionUpdate.MergeWith(aNotification);
+      break;
+    default:
+      MOZ_CRASH("Unsupported notification");
+      break;
+  }
+}
+
+void ContentCacheInParent::FlushPendingNotifications(nsIWidget* aWidget) {
+  MOZ_ASSERT(!PendingEventsNeedingAck());
+
+  // If the BrowserParent's widget has already gone, this can do nothing since
+  // widget is necessary to notify IME of something.
+  if (!aWidget) {
+    return;
+  }
+
+  // New notifications which are notified during flushing pending notifications
+  // should be merged again.
+  const bool pendingEventNeedingAckIncremented =
+      !mHandlingCompositions.IsEmpty();
+  if (pendingEventNeedingAckIncremented) {
+    mHandlingCompositions.LastElement().mPendingEventsNeedingAck++;
+  }
+
+  nsCOMPtr<nsIWidget> widget = aWidget;
+
+  // First, text change notification should be sent because selection change
+  // notification notifies IME of current selection range in the latest content.
+  // So, IME may need the latest content before that.
+  if (mPendingTextChange.HasNotification()) {
+    IMENotification notification(mPendingTextChange);
+    if (!widget->Destroyed()) {
+      mPendingTextChange.Clear();
+      IMEStateManager::NotifyIME(notification, widget, &mBrowserParent);
+    }
+  }
+
+  if (mPendingSelectionChange.HasNotification()) {
+    IMENotification notification(mPendingSelectionChange);
+    if (!widget->Destroyed()) {
+      mPendingSelectionChange.Clear();
+      IMEStateManager::NotifyIME(notification, widget, &mBrowserParent);
+    }
+  }
+
+  // Layout change notification should be notified after selection change
+  // notification because IME may want to query position of new caret position.
+  if (mPendingLayoutChange.HasNotification()) {
+    IMENotification notification(mPendingLayoutChange);
+    if (!widget->Destroyed()) {
+      mPendingLayoutChange.Clear();
+      IMEStateManager::NotifyIME(notification, widget, &mBrowserParent);
+    }
+  }
+
+  // Finally, send composition update notification because it notifies IME of
+  // finishing handling whole sending events.
+  if (mPendingCompositionUpdate.HasNotification()) {
+    IMENotification notification(mPendingCompositionUpdate);
+    if (!widget->Destroyed()) {
+      mPendingCompositionUpdate.Clear();
+      IMEStateManager::NotifyIME(notification, widget, &mBrowserParent);
+    }
+  }
+
+  // Decrement it which was incremented above.
+  if (!mHandlingCompositions.IsEmpty() && pendingEventNeedingAckIncremented &&
+      mHandlingCompositions.LastElement().mPendingEventsNeedingAck) {
+    mHandlingCompositions.LastElement().mPendingEventsNeedingAck--;
+  }
+
+  if (!PendingEventsNeedingAck() && !widget->Destroyed() &&
+      (mPendingTextChange.HasNotification() ||
+       mPendingSelectionChange.HasNotification() ||
+       mPendingLayoutChange.HasNotification() ||
+       mPendingCompositionUpdate.HasNotification())) {
+    FlushPendingNotifications(widget);
+  }
+}
+
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+
+void ContentCacheInParent::RemoveUnnecessaryEventMessageLog() {
+  bool foundLastCompositionStart = false;
+  for (size_t i = mDispatchedEventMessages.Length(); i > 1; i--) {
+    if (mDispatchedEventMessages[i - 1] != eCompositionStart) {
+      continue;
+    }
+    if (!foundLastCompositionStart) {
+      // Find previous eCompositionStart of the latest eCompositionStart.
+      foundLastCompositionStart = true;
+      continue;
+    }
+    // Remove the messages before the last 2 sets of composition events.
+    mDispatchedEventMessages.RemoveElementsAt(0, i - 1);
+    break;
+  }
+  uint32_t numberOfCompositionCommitRequestHandled = 0;
+  foundLastCompositionStart = false;
+  for (size_t i = mReceivedEventMessages.Length(); i > 1; i--) {
+    if (mReceivedEventMessages[i - 1] == eCompositionCommitRequestHandled) {
+      numberOfCompositionCommitRequestHandled++;
+    }
+    if (mReceivedEventMessages[i - 1] != eCompositionStart) {
+      continue;
+    }
+    if (!foundLastCompositionStart) {
+      // Find previous eCompositionStart of the latest eCompositionStart.
+      foundLastCompositionStart = true;
+      continue;
+    }
+    // Remove the messages before the last 2 sets of composition events.
+    mReceivedEventMessages.RemoveElementsAt(0, i - 1);
+    break;
+  }
+
+  if (!numberOfCompositionCommitRequestHandled) {
+    // If there is no eCompositionCommitRequestHandled in
+    // mReceivedEventMessages, we don't need to store log of
+    // RequestIMEToCommmitComposition().
+    mRequestIMEToCommitCompositionResults.Clear();
+  } else {
+    // We need to keep all reason of eCompositionCommitRequestHandled, which
+    // is sent when mRequestIMEToCommitComposition() returns true.
+    // So, we can discard older log than the first
+    // eCompositionCommitRequestHandled in mReceivedEventMessages.
+    for (size_t i = mRequestIMEToCommitCompositionResults.Length(); i > 1;
+         i--) {
+      if (mRequestIMEToCommitCompositionResults[i - 1] ==
+              RequestIMEToCommitCompositionResult::
+                  eReceivedAfterBrowserParentBlur ||
+          mRequestIMEToCommitCompositionResults[i - 1] ==
+              RequestIMEToCommitCompositionResult::eHandledSynchronously) {
+        --numberOfCompositionCommitRequestHandled;
+        if (!numberOfCompositionCommitRequestHandled) {
+          mRequestIMEToCommitCompositionResults.RemoveElementsAt(0, i - 1);
+          break;
+        }
+      }
+    }
+  }
+}
+
+void ContentCacheInParent::AppendEventMessageLog(nsACString& aLog) const {
+  aLog.AppendLiteral("Dispatched Event Message Log:\n");
+  for (EventMessage message : mDispatchedEventMessages) {
+    aLog.AppendLiteral("  ");
+    aLog.Append(ToChar(message));
+    aLog.AppendLiteral("\n");
+  }
+  aLog.AppendLiteral("\nReceived Event Message Log:\n");
+  for (EventMessage message : mReceivedEventMessages) {
+    aLog.AppendLiteral("  ");
+    aLog.Append(ToChar(message));
+    aLog.AppendLiteral("\n");
+  }
+  aLog.AppendLiteral("\nResult of RequestIMEToCommitComposition():\n");
+  for (RequestIMEToCommitCompositionResult result :
+       mRequestIMEToCommitCompositionResults) {
+    aLog.AppendLiteral("  ");
+    aLog.Append(ToReadableText(result));
+    aLog.AppendLiteral("\n");
+  }
+  aLog.AppendLiteral("\n");
+}
+
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+
+/*****************************************************************************
+ * mozilla::ContentCache::Selection
+ *****************************************************************************/
+
+ContentCache::Selection::Selection(
+    const WidgetQueryContentEvent& aQuerySelectedTextEvent)
+    : mAnchor(UINT32_MAX),
+      mFocus(UINT32_MAX),
+      mWritingMode(aQuerySelectedTextEvent.mReply->WritingModeRef()),
+      mHasRange(aQuerySelectedTextEvent.mReply->mOffsetAndData.isSome()) {
+  MOZ_ASSERT(aQuerySelectedTextEvent.mMessage == eQuerySelectedText);
+  MOZ_ASSERT(aQuerySelectedTextEvent.Succeeded());
+  if (mHasRange) {
+    mAnchor = aQuerySelectedTextEvent.mReply->AnchorOffset();
+    mFocus = aQuerySelectedTextEvent.mReply->FocusOffset();
+  }
+}
+
+/*****************************************************************************
+ * mozilla::ContentCache::TextRectArray
+ *****************************************************************************/
+
+LayoutDeviceIntRect ContentCache::TextRectArray::GetRect(
+    uint32_t aOffset) const {
+  LayoutDeviceIntRect rect;
+  if (IsOffsetInRange(aOffset)) {
+    rect = mRects[aOffset - mStart];
+  }
+  return rect;
+}
+
+LayoutDeviceIntRect ContentCache::TextRectArray::GetUnionRect(
+    uint32_t aOffset, uint32_t aLength) const {
+  LayoutDeviceIntRect rect;
+  if (!IsRangeCompletelyInRange(aOffset, aLength)) {
+    return rect;
+  }
+  for (uint32_t i = 0; i < aLength; i++) {
+    rect = rect.Union(mRects[aOffset - mStart + i]);
+  }
+  return rect;
+}
+
+LayoutDeviceIntRect ContentCache::TextRectArray::GetUnionRectAsFarAsPossible(
+    uint32_t aOffset, uint32_t aLength, bool aRoundToExistingOffset) const {
+  LayoutDeviceIntRect rect;
+  if (!HasRects() ||
+      (!aRoundToExistingOffset && !IsOverlappingWith(aOffset, aLength))) {
+    return rect;
+  }
+  uint32_t startOffset = std::max(aOffset, mStart);
+  if (aRoundToExistingOffset && startOffset >= EndOffset()) {
+    startOffset = EndOffset() - 1;
+  }
+  uint32_t endOffset = std::min(aOffset + aLength, EndOffset());
+  if (aRoundToExistingOffset && endOffset < mStart + 1) {
+    endOffset = mStart + 1;
+  }
+  if (NS_WARN_IF(endOffset < startOffset)) {
+    return rect;
+  }
+  for (uint32_t i = 0; i < endOffset - startOffset; i++) {
+    rect = rect.Union(mRects[startOffset - mStart + i]);
+  }
+  return rect;
+}
+
+}  // namespace mozilla
diff --git a/widget/ContentCache.h b/widget/ContentCache.h
new file mode 100644
index 0000000000..3f8b48425e
--- /dev/null
+++ b/widget/ContentCache.h
@@ -0,0 +1,645 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ContentCache_h
+#define mozilla_ContentCache_h
+
+#include <stdint.h>
+
+#include "mozilla/widget/IMEData.h"
+#include "mozilla/ipc/IPCForwards.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/ToString.h"
+#include "mozilla/WritingModes.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "Units.h"
+
+class nsIWidget;
+
+namespace mozilla {
+
+class ContentCacheInParent;
+
+namespace dom {
+class BrowserParent;
+}  // namespace dom
+
+/**
+ * ContentCache stores various information of the child content.
+ * This class has members which are necessary both in parent process and
+ * content process.
+ */
+
+class ContentCache {
+ public:
+  using RectArray = CopyableTArray<LayoutDeviceIntRect>;
+  using IMENotification = widget::IMENotification;
+
+  ContentCache() = default;
+
+  [[nodiscard]] bool IsValid() const;
+
+ protected:
+  void AssertIfInvalid() const;
+
+  // Whole text in the target
+  Maybe<nsString> mText;
+
+  // Start offset of the composition string.
+  Maybe<uint32_t> mCompositionStart;
+
+  enum { ePrevCharRect = 1, eNextCharRect = 0 };
+
+  struct Selection final {
+    // Following values are offset in "flat text".
+    uint32_t mAnchor;
+    uint32_t mFocus;
+
+    WritingMode mWritingMode;
+
+    bool mHasRange;
+
+    // Character rects at previous and next character of mAnchor and mFocus.
+    // The reason why ContentCache needs to store each previous character of
+    // them is IME may query character rect of the last character of a line
+    // when caret is at the end of the line.
+    // Note that use ePrevCharRect and eNextCharRect for accessing each item.
+    LayoutDeviceIntRect mAnchorCharRects[2];
+    LayoutDeviceIntRect mFocusCharRects[2];
+
+    // Whole rect of selected text. This is empty if the selection is collapsed.
+    LayoutDeviceIntRect mRect;
+
+    Selection() : mAnchor(UINT32_MAX), mFocus(UINT32_MAX), mHasRange(false) {
+      ClearRects();
+    };
+
+    explicit Selection(
+        const IMENotification::SelectionChangeDataBase& aSelectionChangeData)
+        : mAnchor(UINT32_MAX),
+          mFocus(UINT32_MAX),
+          mWritingMode(aSelectionChangeData.GetWritingMode()),
+          mHasRange(aSelectionChangeData.HasRange()) {
+      if (mHasRange) {
+        mAnchor = aSelectionChangeData.AnchorOffset();
+        mFocus = aSelectionChangeData.FocusOffset();
+      }
+    }
+
+    [[nodiscard]] bool IsValidIn(const nsAString& aText) const {
+      return !mHasRange ||
+             (mAnchor <= aText.Length() && mFocus <= aText.Length());
+    }
+
+    explicit Selection(const WidgetQueryContentEvent& aQuerySelectedTextEvent);
+
+    void ClearRects() {
+      for (auto& rect : mAnchorCharRects) {
+        rect.SetEmpty();
+      }
+      for (auto& rect : mFocusCharRects) {
+        rect.SetEmpty();
+      }
+      mRect.SetEmpty();
+    }
+    bool HasRects() const {
+      for (const auto& rect : mAnchorCharRects) {
+        if (!rect.IsEmpty()) {
+          return true;
+        }
+      }
+      for (const auto& rect : mFocusCharRects) {
+        if (!rect.IsEmpty()) {
+          return true;
+        }
+      }
+      return !mRect.IsEmpty();
+    }
+
+    bool IsCollapsed() const { return !mHasRange || mFocus == mAnchor; }
+    bool Reversed() const {
+      MOZ_ASSERT(mHasRange);
+      return mFocus < mAnchor;
+    }
+    uint32_t StartOffset() const {
+      MOZ_ASSERT(mHasRange);
+      return Reversed() ? mFocus : mAnchor;
+    }
+    uint32_t EndOffset() const {
+      MOZ_ASSERT(mHasRange);
+      return Reversed() ? mAnchor : mFocus;
+    }
+    uint32_t Length() const {
+      MOZ_ASSERT(mHasRange);
+      return Reversed() ? mAnchor - mFocus : mFocus - mAnchor;
+    }
+    LayoutDeviceIntRect StartCharRect() const {
+      return Reversed() ? mFocusCharRects[eNextCharRect]
+                        : mAnchorCharRects[eNextCharRect];
+    }
+    LayoutDeviceIntRect EndCharRect() const {
+      return Reversed() ? mAnchorCharRects[eNextCharRect]
+                        : mFocusCharRects[eNextCharRect];
+    }
+
+    friend std::ostream& operator<<(std::ostream& aStream,
+                                    const Selection& aSelection) {
+      aStream << "{ ";
+      if (!aSelection.mHasRange) {
+        aStream << "HasRange()=false";
+      } else {
+        aStream << "mAnchor=" << aSelection.mAnchor
+                << ", mFocus=" << aSelection.mFocus << ", mWritingMode="
+                << ToString(aSelection.mWritingMode).c_str();
+      }
+      if (aSelection.HasRects()) {
+        if (aSelection.mAnchor > 0) {
+          aStream << ", mAnchorCharRects[ePrevCharRect]="
+                  << aSelection.mAnchorCharRects[ContentCache::ePrevCharRect];
+        }
+        aStream << ", mAnchorCharRects[eNextCharRect]="
+                << aSelection.mAnchorCharRects[ContentCache::eNextCharRect];
+        if (aSelection.mFocus > 0) {
+          aStream << ", mFocusCharRects[ePrevCharRect]="
+                  << aSelection.mFocusCharRects[ContentCache::ePrevCharRect];
+        }
+        aStream << ", mFocusCharRects[eNextCharRect]="
+                << aSelection.mFocusCharRects[ContentCache::eNextCharRect]
+                << ", mRect=" << aSelection.mRect;
+      }
+      if (aSelection.mHasRange) {
+        aStream << ", Reversed()=" << (aSelection.Reversed() ? "true" : "false")
+                << ", StartOffset()=" << aSelection.StartOffset()
+                << ", EndOffset()=" << aSelection.EndOffset()
+                << ", IsCollapsed()="
+                << (aSelection.IsCollapsed() ? "true" : "false")
+                << ", Length()=" << aSelection.Length();
+      }
+      aStream << " }";
+      return aStream;
+    }
+  };
+  Maybe<Selection> mSelection;
+
+  // Stores first char rect because Yosemite's Japanese IME sometimes tries
+  // to query it.  If there is no text, this is caret rect.
+  LayoutDeviceIntRect mFirstCharRect;
+
+  struct Caret final {
+    uint32_t mOffset = 0u;
+    LayoutDeviceIntRect mRect;
+
+    explicit Caret(uint32_t aOffset, LayoutDeviceIntRect aCaretRect)
+        : mOffset(aOffset), mRect(aCaretRect) {}
+
+    uint32_t Offset() const { return mOffset; }
+    bool HasRect() const { return !mRect.IsEmpty(); }
+
+    [[nodiscard]] bool IsValidIn(const nsAString& aText) const {
+      return mOffset <= aText.Length();
+    }
+
+    friend std::ostream& operator<<(std::ostream& aStream,
+                                    const Caret& aCaret) {
+      aStream << "{ mOffset=" << aCaret.mOffset;
+      if (aCaret.HasRect()) {
+        aStream << ", mRect=" << aCaret.mRect;
+      }
+      return aStream << " }";
+    }
+
+   private:
+    // For ParamTraits<Caret>
+    Caret() = default;
+
+    friend struct IPC::ParamTraits<ContentCache::Caret>;
+    ALLOW_DEPRECATED_READPARAM
+  };
+  Maybe<Caret> mCaret;
+
+  struct TextRectArray final {
+    uint32_t mStart = 0u;
+    RectArray mRects;
+
+    explicit TextRectArray(uint32_t aStartOffset) : mStart(aStartOffset) {}
+
+    bool HasRects() const { return Length() > 0; }
+    uint32_t StartOffset() const { return mStart; }
+    uint32_t EndOffset() const {
+      CheckedInt<uint32_t> endOffset =
+          CheckedInt<uint32_t>(mStart) + mRects.Length();
+      return endOffset.isValid() ? endOffset.value() : UINT32_MAX;
+    }
+    uint32_t Length() const { return EndOffset() - mStart; }
+    bool IsOffsetInRange(uint32_t aOffset) const {
+      return StartOffset() <= aOffset && aOffset < EndOffset();
+    }
+    bool IsRangeCompletelyInRange(uint32_t aOffset, uint32_t aLength) const {
+      CheckedInt<uint32_t> endOffset = CheckedInt<uint32_t>(aOffset) + aLength;
+      if (NS_WARN_IF(!endOffset.isValid())) {
+        return false;
+      }
+      return IsOffsetInRange(aOffset) && aOffset + aLength <= EndOffset();
+    }
+    bool IsOverlappingWith(uint32_t aOffset, uint32_t aLength) const {
+      if (!HasRects() || aOffset == UINT32_MAX || !aLength) {
+        return false;
+      }
+      CheckedInt<uint32_t> endOffset = CheckedInt<uint32_t>(aOffset) + aLength;
+      if (NS_WARN_IF(!endOffset.isValid())) {
+        return false;
+      }
+      return aOffset < EndOffset() && endOffset.value() > mStart;
+    }
+    LayoutDeviceIntRect GetRect(uint32_t aOffset) const;
+    LayoutDeviceIntRect GetUnionRect(uint32_t aOffset, uint32_t aLength) const;
+    LayoutDeviceIntRect GetUnionRectAsFarAsPossible(
+        uint32_t aOffset, uint32_t aLength, bool aRoundToExistingOffset) const;
+
+    friend std::ostream& operator<<(std::ostream& aStream,
+                                    const TextRectArray& aTextRectArray) {
+      aStream << "{ mStart=" << aTextRectArray.mStart
+              << ", mRects={ Length()=" << aTextRectArray.Length();
+      if (aTextRectArray.HasRects()) {
+        aStream << ", Elements()=[ ";
+        static constexpr uint32_t kMaxPrintRects = 4;
+        const uint32_t kFirstHalf = aTextRectArray.Length() <= kMaxPrintRects
+                                        ? UINT32_MAX
+                                        : (kMaxPrintRects + 1) / 2;
+        const uint32_t kSecondHalf =
+            aTextRectArray.Length() <= kMaxPrintRects ? 0 : kMaxPrintRects / 2;
+        for (uint32_t i = 0; i < aTextRectArray.Length(); i++) {
+          if (i > 0) {
+            aStream << ", ";
+          }
+          aStream << ToString(aTextRectArray.mRects[i]).c_str();
+          if (i + 1 == kFirstHalf) {
+            aStream << " ...";
+            i = aTextRectArray.Length() - kSecondHalf - 1;
+          }
+        }
+      }
+      return aStream << " ] } }";
+    }
+
+   private:
+    // For ParamTraits<TextRectArray>
+    TextRectArray() = default;
+
+    friend struct IPC::ParamTraits<ContentCache::TextRectArray>;
+    ALLOW_DEPRECATED_READPARAM
+  };
+  Maybe<TextRectArray> mTextRectArray;
+  Maybe<TextRectArray> mLastCommitStringTextRectArray;
+
+  LayoutDeviceIntRect mEditorRect;
+
+  friend class ContentCacheInParent;
+  friend struct IPC::ParamTraits<ContentCache>;
+  friend struct IPC::ParamTraits<ContentCache::Selection>;
+  friend struct IPC::ParamTraits<ContentCache::Caret>;
+  friend struct IPC::ParamTraits<ContentCache::TextRectArray>;
+  friend std::ostream& operator<<(
+      std::ostream& aStream,
+      const Selection& aSelection);  // For e(Prev|Next)CharRect
+  ALLOW_DEPRECATED_READPARAM
+};
+
+class ContentCacheInChild final : public ContentCache {
+ public:
+  ContentCacheInChild() = default;
+
+  /**
+   * Called when composition event will be dispatched in this process from
+   * PuppetWidget.
+   */
+  void OnCompositionEvent(const WidgetCompositionEvent& aCompositionEvent);
+
+  /**
+   * When IME loses focus, this should be called and making this forget the
+   * content for reducing footprint.
+   */
+  void Clear();
+
+  /**
+   * Cache*() retrieves the latest content information and store them.
+   * Be aware, CacheSelection() calls CacheCaretAndTextRects(),
+   * CacheCaretAndTextRects() calls CacheCaret() and CacheTextRects(), and
+   * CacheText() calls CacheSelection().  So, related data is also retrieved
+   * automatically.
+   */
+  bool CacheEditorRect(nsIWidget* aWidget,
+                       const IMENotification* aNotification = nullptr);
+  bool CacheCaretAndTextRects(nsIWidget* aWidget,
+                              const IMENotification* aNotification = nullptr);
+  bool CacheText(nsIWidget* aWidget,
+                 const IMENotification* aNotification = nullptr);
+
+  bool CacheAll(nsIWidget* aWidget,
+                const IMENotification* aNotification = nullptr);
+
+  /**
+   * SetSelection() modifies selection with specified raw data. And also this
+   * tries to retrieve text rects too.
+   *
+   * @return true if the selection is cached.  Otherwise, false.
+   */
+  [[nodiscard]] bool SetSelection(
+      nsIWidget* aWidget,
+      const IMENotification::SelectionChangeDataBase& aSelectionChangeData);
+
+ private:
+  bool QueryCharRect(nsIWidget* aWidget, uint32_t aOffset,
+                     LayoutDeviceIntRect& aCharRect) const;
+  bool QueryCharRectArray(nsIWidget* aWidget, uint32_t aOffset,
+                          uint32_t aLength, RectArray& aCharRectArray) const;
+  bool CacheSelection(nsIWidget* aWidget,
+                      const IMENotification* aNotification = nullptr);
+  bool CacheCaret(nsIWidget* aWidget,
+                  const IMENotification* aNotification = nullptr);
+  bool CacheTextRects(nsIWidget* aWidget,
+                      const IMENotification* aNotification = nullptr);
+
+  // Once composition is committed, all of the commit string may be composed
+  // again by Kakutei-Undo of Japanese IME.  Therefore, we need to keep
+  // storing the last composition start to cache all character rects of the
+  // last commit string.
+  Maybe<OffsetAndData<uint32_t>> mLastCommit;
+};
+
+class ContentCacheInParent final : public ContentCache {
+ public:
+  ContentCacheInParent() = delete;
+  explicit ContentCacheInParent(dom::BrowserParent& aBrowserParent);
+
+  /**
+   * AssignContent() is called when BrowserParent receives ContentCache from
+   * the content process.  This doesn't copy composition information because
+   * it's managed by BrowserParent itself.
+   */
+  void AssignContent(const ContentCache& aOther, nsIWidget* aWidget,
+                     const IMENotification* aNotification = nullptr);
+
+  /**
+   * HandleQueryContentEvent() sets content data to aEvent.mReply.
+   *
+   * For eQuerySelectedText, fail if the cache doesn't contain the whole
+   *  selected range. (This shouldn't happen because PuppetWidget should have
+   *  already sent the whole selection.)
+   *
+   * For eQueryTextContent, fail only if the cache doesn't overlap with
+   *  the queried range. Note the difference from above. We use
+   *  this behavior because a normal eQueryTextContent event is allowed to
+   *  have out-of-bounds offsets, so that widget can request content without
+   *  knowing the exact length of text. It's up to widget to handle cases when
+   *  the returned offset/length are different from the queried offset/length.
+   *
+   * For eQueryTextRect, fail if cached offset/length aren't equals to input.
+   *   Cocoa widget always queries selected offset, so it works on it.
+   *
+   * For eQueryCaretRect, fail if cached offset isn't equals to input
+   *
+   * For eQueryEditorRect, always success
+   */
+  bool HandleQueryContentEvent(WidgetQueryContentEvent& aEvent,
+                               nsIWidget* aWidget) const;
+
+  /**
+   * OnCompositionEvent() should be called before sending composition string.
+   * This returns true if the event should be sent.  Otherwise, false.
+   */
+  bool OnCompositionEvent(const WidgetCompositionEvent& aCompositionEvent);
+
+  /**
+   * OnSelectionEvent() should be called before sending selection event.
+   */
+  void OnSelectionEvent(const WidgetSelectionEvent& aSelectionEvent);
+
+  /**
+   * OnEventNeedingAckHandled() should be called after the child process
+   * handles a sent event which needs acknowledging.
+   *
+   * WARNING: This may send notifications to IME.  That might cause destroying
+   *          BrowserParent or aWidget.  Therefore, the caller must not destroy
+   *          this instance during a call of this method.
+   */
+  void OnEventNeedingAckHandled(nsIWidget* aWidget, EventMessage aMessage,
+                                uint32_t aCompositionId);
+
+  /**
+   * RequestIMEToCommitComposition() requests aWidget to commit or cancel
+   * composition.  If it's handled synchronously, this returns true.
+   *
+   * @param aWidget     The widget to be requested to commit or cancel
+   *                    the composition.
+   * @param aCancel     When the caller tries to cancel the composition, true.
+   *                    Otherwise, i.e., tries to commit the composition, false.
+   * @param aCompositionId
+   *                    The composition ID which should be committed or
+   *                    canceled.
+   * @param aCommittedString    The committed string (i.e., the last data of
+   *                            dispatched composition events during requesting
+   *                            IME to commit composition.
+   * @return            Whether the composition is actually committed
+   *                    synchronously.
+   */
+  bool RequestIMEToCommitComposition(nsIWidget* aWidget, bool aCancel,
+                                     uint32_t aCompositionId,
+                                     nsAString& aCommittedString);
+
+  /**
+   * MaybeNotifyIME() may notify IME of the notification.  If child process
+   * hasn't been handled all sending events yet, this stores the notification
+   * and flush it later.
+   */
+  void MaybeNotifyIME(nsIWidget* aWidget, const IMENotification& aNotification);
+
+ private:
+  struct HandlingCompositionData;
+
+  // Return true when the widget in this process thinks that IME has
+  // composition.  So, this returns true when there is at least one handling
+  // composition data and the last handling composition has not dispatched
+  // composition commit event to the remote process yet.
+  [[nodiscard]] bool WidgetHasComposition() const {
+    return !mHandlingCompositions.IsEmpty() &&
+           !mHandlingCompositions.LastElement().mSentCommitEvent;
+  }
+
+  // Return true if there is a pending composition which has already sent
+  // a commit event to the remote process, but not yet handled by it.
+  [[nodiscard]] bool HasPendingCommit() const {
+    for (const HandlingCompositionData& data : mHandlingCompositions) {
+      if (data.mSentCommitEvent) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  // Return the number of composition events and set selection events which were
+  // sent to the remote process, but we've not verified that the remote process
+  // finished handling it.
+  [[nodiscard]] uint32_t PendingEventsNeedingAck() const {
+    uint32_t ret = mPendingSetSelectionEventNeedingAck;
+    for (const HandlingCompositionData& data : mHandlingCompositions) {
+      ret += data.mPendingEventsNeedingAck;
+    }
+    return ret;
+  }
+
+  [[nodiscard]] HandlingCompositionData* GetHandlingCompositionData(
+      uint32_t aCompositionId) {
+    for (HandlingCompositionData& data : mHandlingCompositions) {
+      if (data.mCompositionId == aCompositionId) {
+        return &data;
+      }
+    }
+    return nullptr;
+  }
+  [[nodiscard]] const HandlingCompositionData* GetHandlingCompositionData(
+      uint32_t aCompositionId) const {
+    return const_cast<ContentCacheInParent*>(this)->GetHandlingCompositionData(
+        aCompositionId);
+  }
+
+  IMENotification mPendingSelectionChange;
+  IMENotification mPendingTextChange;
+  IMENotification mPendingLayoutChange;
+  IMENotification mPendingCompositionUpdate;
+
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  // Log of event messages to be output to crash report.
+  nsTArray<EventMessage> mDispatchedEventMessages;
+  nsTArray<EventMessage> mReceivedEventMessages;
+  // Log of RequestIMEToCommitComposition() in the last 2 compositions.
+  enum class RequestIMEToCommitCompositionResult : uint8_t {
+    eToOldCompositionReceived,
+    eToUnknownCompositionReceived,
+    eToCommittedCompositionReceived,
+    eReceivedAfterBrowserParentBlur,
+    eReceivedButNoTextComposition,
+    eReceivedButForDifferentTextComposition,
+    eHandledAsynchronously,
+    eHandledSynchronously,
+  };
+  const char* ToReadableText(
+      RequestIMEToCommitCompositionResult aResult) const {
+    switch (aResult) {
+      case RequestIMEToCommitCompositionResult::eToOldCompositionReceived:
+        return "Commit request is not handled because it's for "
+               "older composition";
+      case RequestIMEToCommitCompositionResult::eToUnknownCompositionReceived:
+        return "Commit request is not handled because it's for "
+               "unknown composition";
+      case RequestIMEToCommitCompositionResult::eToCommittedCompositionReceived:
+        return "Commit request is not handled because BrowserParent has "
+               "already "
+               "sent commit event for the composition";
+      case RequestIMEToCommitCompositionResult::eReceivedAfterBrowserParentBlur:
+        return "Commit request is handled with stored composition string "
+               "because BrowserParent has already lost focus";
+      case RequestIMEToCommitCompositionResult::eReceivedButNoTextComposition:
+        return "Commit request is not handled because there is no "
+               "TextComposition instance";
+      case RequestIMEToCommitCompositionResult::
+          eReceivedButForDifferentTextComposition:
+        return "Commit request is handled with stored composition string "
+               "because new TextComposition is active";
+      case RequestIMEToCommitCompositionResult::eHandledAsynchronously:
+        return "Commit request is handled but IME doesn't commit current "
+               "composition synchronously";
+      case RequestIMEToCommitCompositionResult::eHandledSynchronously:
+        return "Commit request is handled synchronously";
+      default:
+        return "Unknown reason";
+    }
+  }
+  nsTArray<RequestIMEToCommitCompositionResult>
+      mRequestIMEToCommitCompositionResults;
+#endif  // MOZ_DIAGNOSTIC_ASSERT_ENABLED
+
+  // Stores pending compositions (meaning eCompositionStart was dispatched, but
+  // eCompositionCommit(AsIs) has not been handled by the remote process yet).
+  struct HandlingCompositionData {
+    // The lasted composition string which was sent to the remote process.
+    nsString mCompositionString;
+    // The composition ID of a handling composition with the instance.
+    uint32_t mCompositionId;
+    // Increased when sending composition events and decreased when the
+    // remote process finished handling the events.
+    uint32_t mPendingEventsNeedingAck = 0u;
+    // true if eCompositionCommit(AsIs) has already been sent to the remote
+    // process.
+    bool mSentCommitEvent = false;
+
+    explicit HandlingCompositionData(uint32_t aCompositionId)
+        : mCompositionId(aCompositionId) {}
+  };
+  AutoTArray<HandlingCompositionData, 2> mHandlingCompositions;
+
+  // mBrowserParent is owner of the instance.
+  dom::BrowserParent& MOZ_NON_OWNING_REF mBrowserParent;
+  // This is not nullptr only while the instance is requesting IME to
+  // composition.  Then, data value of dispatched composition events should
+  // be stored into the instance.
+  nsAString* mCommitStringByRequest;
+  // mCompositionStartInChild stores current composition start offset in the
+  // remote process.
+  Maybe<uint32_t> mCompositionStartInChild;
+  // Increased when sending eSetSelection events and decreased when the remote
+  // process finished handling the events.  Note that eSetSelection may be
+  // dispatched without composition.  Therefore, we need to count it with this.
+  uint32_t mPendingSetSelectionEventNeedingAck = 0u;
+  // mPendingCommitLength is commit string length of the first pending
+  // composition.  This is used by relative offset query events when querying
+  // new composition start offset.
+  // Note that when mHandlingCompositions has 2 or more elements, i.e., there
+  // are 2 or more pending compositions, this cache won't be used because in
+  // such case, anyway ContentCacheInParent cannot return proper character rect.
+  uint32_t mPendingCommitLength;
+  // mIsChildIgnoringCompositionEvents is set to true if the child process
+  // requests commit composition whose commit has already been sent to it.
+  // Then, set to false when the child process ignores the commit event.
+  bool mIsChildIgnoringCompositionEvents;
+
+  /**
+   * When following methods' aRoundToExistingOffset is true, even if specified
+   * offset or range is out of bounds, the result is computed with the existing
+   * cache forcibly.
+   */
+  bool GetCaretRect(uint32_t aOffset, bool aRoundToExistingOffset,
+                    LayoutDeviceIntRect& aCaretRect) const;
+  bool GetTextRect(uint32_t aOffset, bool aRoundToExistingOffset,
+                   LayoutDeviceIntRect& aTextRect) const;
+  bool GetUnionTextRects(uint32_t aOffset, uint32_t aLength,
+                         bool aRoundToExistingOffset,
+                         LayoutDeviceIntRect& aUnionTextRect) const;
+
+  void FlushPendingNotifications(nsIWidget* aWidget);
+
+#if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  /**
+   * Remove unnecessary messages from mDispatchedEventMessages and
+   * mReceivedEventMessages.
+   */
+  void RemoveUnnecessaryEventMessageLog();
+
+  /**
+   * Append event message log to aLog.
+   */
+  void AppendEventMessageLog(nsACString& aLog) const;
+#endif  // #if MOZ_DIAGNOSTIC_ASSERT_ENABLED
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_ContentCache_h
diff --git a/widget/ContentData.cpp b/widget/ContentData.cpp
new file mode 100644
index 0000000000..529ccc5c0f
--- /dev/null
+++ b/widget/ContentData.cpp
@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ContentData.h"
+
+#include "TextEvents.h"
+
+namespace mozilla {
+
+/******************************************************************************
+ * ContentSelection
+ ******************************************************************************/
+
+ContentSelection::ContentSelection(
+    const WidgetQueryContentEvent& aSelectedTextEvent)
+    : mWritingMode(aSelectedTextEvent.mReply->WritingModeRef()) {
+  MOZ_ASSERT(aSelectedTextEvent.mMessage == eQuerySelectedText);
+  MOZ_ASSERT(aSelectedTextEvent.Succeeded());
+  if (aSelectedTextEvent.mReply->mOffsetAndData.isSome()) {
+    mOffsetAndData =
+        Some(OffsetAndData<uint32_t>(aSelectedTextEvent.mReply->StartOffset(),
+                                     aSelectedTextEvent.mReply->DataRef(),
+                                     OffsetAndDataFor::SelectedString));
+  }
+}
+
+}  // namespace mozilla
diff --git a/widget/ContentData.h b/widget/ContentData.h
new file mode 100644
index 0000000000..3e641a2684
--- /dev/null
+++ b/widget/ContentData.h
@@ -0,0 +1,84 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ContentData_h
+#define mozilla_ContentData_h
+
+#include <sstream>
+
+#include "mozilla/Attributes.h"
+#include "mozilla/Debug.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/WritingModes.h"
+#include "mozilla/widget/IMEData.h"
+
+/**
+ * This file is intended for declaring classes which store DOM content data for
+ * widget classes.  Those data should be retrived by `WidgetQueryContentEvent`,
+ * notified with `IMENotification`, or set assumed data as result of dispatching
+ * widget events such as `WidgetKeyboardEvent`, `WidgetCompositionEvent`,
+ * `WidgetSelectionEvent` etc.
+ */
+
+namespace mozilla {
+
+/**
+ * ContentSelection stores DOM selection in flattend text by
+ * ContentEventHandler.  It should be retrieved with `eQuerySelectedText` event,
+ * notified with `NOTIFY_IME_OF_SELECTION_CHANGE` or set by widget itself.
+ */
+class ContentSelection {
+ public:
+  using SelectionChangeDataBase =
+      widget::IMENotification::SelectionChangeDataBase;
+  ContentSelection() = default;
+  explicit ContentSelection(const SelectionChangeDataBase& aSelectionChangeData)
+      : mOffsetAndData(Some(aSelectionChangeData.ToUint32OffsetAndData())),
+        mWritingMode(aSelectionChangeData.GetWritingMode()) {}
+  explicit ContentSelection(const WidgetQueryContentEvent& aSelectedTextEvent);
+  ContentSelection(uint32_t aOffset, const WritingMode& aWritingMode)
+      : mOffsetAndData(Some(OffsetAndData<uint32_t>(
+            aOffset, EmptyString(), OffsetAndDataFor::SelectedString))),
+        mWritingMode(aWritingMode) {}
+
+  const OffsetAndData<uint32_t>& OffsetAndDataRef() const {
+    return mOffsetAndData.ref();
+  }
+
+  void Collapse(uint32_t aOffset) {
+    if (mOffsetAndData.isSome()) {
+      mOffsetAndData->Collapse(aOffset);
+    } else {
+      mOffsetAndData.emplace(aOffset, EmptyString(),
+                             OffsetAndDataFor::SelectedString);
+    }
+  }
+  void Clear() {
+    mOffsetAndData.reset();
+    mWritingMode = WritingMode();
+  }
+
+  bool HasRange() const { return mOffsetAndData.isSome(); }
+  const WritingMode& WritingModeRef() const { return mWritingMode; }
+
+  friend std::ostream& operator<<(std::ostream& aStream,
+                                  const ContentSelection& aContentSelection) {
+    if (aContentSelection.HasRange()) {
+      return aStream << "{ HasRange()=false }";
+    }
+    aStream << "{ mOffsetAndData=" << aContentSelection.mOffsetAndData
+            << ", mWritingMode=" << aContentSelection.mWritingMode << " }";
+    return aStream;
+  }
+
+ private:
+  Maybe<OffsetAndData<uint32_t>> mOffsetAndData;
+  WritingMode mWritingMode;
+};
+
+}  // namespace mozilla
+
+#endif  // #ifndef mozilla_ContentData_h
diff --git a/widget/ContentEvents.h b/widget/ContentEvents.h
new file mode 100644
index 0000000000..e43de98c9f
--- /dev/null
+++ b/widget/ContentEvents.h
@@ -0,0 +1,313 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ContentEvents_h__
+#define mozilla_ContentEvents_h__
+
+#include <stdint.h>
+
+#include "mozilla/BasicEvents.h"
+#include "mozilla/dom/DataTransfer.h"
+#include "mozilla/dom/EventTarget.h"
+#include "nsCOMPtr.h"
+#include "nsRect.h"
+#include "nsString.h"
+
+class nsIContent;
+
+namespace mozilla {
+
+/******************************************************************************
+ * mozilla::InternalScrollPortEvent
+ ******************************************************************************/
+
+class InternalScrollPortEvent : public WidgetGUIEvent {
+ public:
+  virtual InternalScrollPortEvent* AsScrollPortEvent() override { return this; }
+
+  enum OrientType { eVertical, eHorizontal, eBoth };
+
+  InternalScrollPortEvent(bool aIsTrusted, EventMessage aMessage,
+                          nsIWidget* aWidget,
+                          const WidgetEventTime* aTime = nullptr)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eScrollPortEventClass,
+                       aTime),
+        mOrient(eVertical) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eScrollPortEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    InternalScrollPortEvent* result =
+        new InternalScrollPortEvent(false, mMessage, nullptr, this);
+    result->AssignScrollPortEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  OrientType mOrient;
+
+  void AssignScrollPortEventData(const InternalScrollPortEvent& aEvent,
+                                 bool aCopyTargets) {
+    AssignGUIEventData(aEvent, aCopyTargets);
+
+    mOrient = aEvent.mOrient;
+  }
+};
+
+/******************************************************************************
+ * mozilla::InternalScrollPortEvent
+ ******************************************************************************/
+
+class InternalScrollAreaEvent : public WidgetGUIEvent {
+ public:
+  virtual InternalScrollAreaEvent* AsScrollAreaEvent() override { return this; }
+
+  InternalScrollAreaEvent(bool aIsTrusted, EventMessage aMessage,
+                          nsIWidget* aWidget,
+                          const WidgetEventTime* aTime = nullptr)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eScrollAreaEventClass,
+                       aTime) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eScrollAreaEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    InternalScrollAreaEvent* result =
+        new InternalScrollAreaEvent(false, mMessage, nullptr, this);
+    result->AssignScrollAreaEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  nsRect mArea;
+
+  void AssignScrollAreaEventData(const InternalScrollAreaEvent& aEvent,
+                                 bool aCopyTargets) {
+    AssignGUIEventData(aEvent, aCopyTargets);
+
+    mArea = aEvent.mArea;
+  }
+};
+
+/******************************************************************************
+ * mozilla::InternalFormEvent
+ *
+ * We hold the originating form control for form submit and reset events.
+ * mOriginator is a weak pointer (does not hold a strong reference).
+ ******************************************************************************/
+
+class InternalFormEvent : public WidgetEvent {
+ public:
+  virtual InternalFormEvent* AsFormEvent() override { return this; }
+
+  InternalFormEvent(bool aIsTrusted, EventMessage aMessage,
+                    const WidgetEventTime* aTime = nullptr)
+      : WidgetEvent(aIsTrusted, aMessage, eFormEventClass, aTime),
+        mOriginator(nullptr) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eFormEventClass,
+               "Duplicate() must be overridden by sub class");
+    InternalFormEvent* result = new InternalFormEvent(false, mMessage, this);
+    result->AssignFormEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  nsIContent* mOriginator;
+
+  void AssignFormEventData(const InternalFormEvent& aEvent, bool aCopyTargets) {
+    AssignEventData(aEvent, aCopyTargets);
+
+    // Don't copy mOriginator due to a weak pointer.
+  }
+};
+
+/******************************************************************************
+ * mozilla::InternalClipboardEvent
+ ******************************************************************************/
+
+class InternalClipboardEvent : public WidgetEvent {
+ public:
+  virtual InternalClipboardEvent* AsClipboardEvent() override { return this; }
+
+  InternalClipboardEvent(bool aIsTrusted, EventMessage aMessage,
+                         const WidgetEventTime* aTime = nullptr)
+      : WidgetEvent(aIsTrusted, aMessage, eClipboardEventClass, aTime) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eClipboardEventClass,
+               "Duplicate() must be overridden by sub class");
+    InternalClipboardEvent* result =
+        new InternalClipboardEvent(false, mMessage, this);
+    result->AssignClipboardEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  nsCOMPtr<dom::DataTransfer> mClipboardData;
+
+  void AssignClipboardEventData(const InternalClipboardEvent& aEvent,
+                                bool aCopyTargets) {
+    AssignEventData(aEvent, aCopyTargets);
+
+    mClipboardData = aEvent.mClipboardData;
+  }
+};
+
+/******************************************************************************
+ * mozilla::InternalFocusEvent
+ ******************************************************************************/
+
+class InternalFocusEvent : public InternalUIEvent {
+ public:
+  virtual InternalFocusEvent* AsFocusEvent() override { return this; }
+
+  InternalFocusEvent(bool aIsTrusted, EventMessage aMessage,
+                     const WidgetEventTime* aTime = nullptr)
+      : InternalUIEvent(aIsTrusted, aMessage, eFocusEventClass, aTime),
+        mFromRaise(false),
+        mIsRefocus(false) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eFocusEventClass,
+               "Duplicate() must be overridden by sub class");
+    InternalFocusEvent* result = new InternalFocusEvent(false, mMessage, this);
+    result->AssignFocusEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  bool mFromRaise;
+  bool mIsRefocus;
+
+  void AssignFocusEventData(const InternalFocusEvent& aEvent,
+                            bool aCopyTargets) {
+    AssignUIEventData(aEvent, aCopyTargets);
+
+    mFromRaise = aEvent.mFromRaise;
+    mIsRefocus = aEvent.mIsRefocus;
+  }
+};
+
+/******************************************************************************
+ * mozilla::InternalTransitionEvent
+ ******************************************************************************/
+
+class InternalTransitionEvent : public WidgetEvent {
+ public:
+  virtual InternalTransitionEvent* AsTransitionEvent() override { return this; }
+
+  InternalTransitionEvent(bool aIsTrusted, EventMessage aMessage,
+                          const WidgetEventTime* aTime = nullptr)
+      : WidgetEvent(aIsTrusted, aMessage, eTransitionEventClass, aTime),
+        mElapsedTime(0.0) {}
+
+  InternalTransitionEvent(const InternalTransitionEvent& aOther) = delete;
+  InternalTransitionEvent& operator=(const InternalTransitionEvent& aOther) =
+      delete;
+  InternalTransitionEvent(InternalTransitionEvent&& aOther) = default;
+  InternalTransitionEvent& operator=(InternalTransitionEvent&& aOther) =
+      default;
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eTransitionEventClass,
+               "Duplicate() must be overridden by sub class");
+    InternalTransitionEvent* result =
+        new InternalTransitionEvent(false, mMessage, this);
+    result->AssignTransitionEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  nsString mPropertyName;
+  nsString mPseudoElement;
+  float mElapsedTime;
+
+  void AssignTransitionEventData(const InternalTransitionEvent& aEvent,
+                                 bool aCopyTargets) {
+    AssignEventData(aEvent, aCopyTargets);
+
+    mPropertyName = aEvent.mPropertyName;
+    mElapsedTime = aEvent.mElapsedTime;
+    mPseudoElement = aEvent.mPseudoElement;
+  }
+};
+
+/******************************************************************************
+ * mozilla::InternalAnimationEvent
+ ******************************************************************************/
+
+class InternalAnimationEvent : public WidgetEvent {
+ public:
+  virtual InternalAnimationEvent* AsAnimationEvent() override { return this; }
+
+  InternalAnimationEvent(bool aIsTrusted, EventMessage aMessage,
+                         const WidgetEventTime* aTime = nullptr)
+      : WidgetEvent(aIsTrusted, aMessage, eAnimationEventClass, aTime),
+        mElapsedTime(0.0) {}
+
+  InternalAnimationEvent(const InternalAnimationEvent& aOther) = delete;
+  InternalAnimationEvent& operator=(const InternalAnimationEvent& aOther) =
+      delete;
+  InternalAnimationEvent(InternalAnimationEvent&& aOther) = default;
+  InternalAnimationEvent& operator=(InternalAnimationEvent&& aOther) = default;
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eAnimationEventClass,
+               "Duplicate() must be overridden by sub class");
+    InternalAnimationEvent* result =
+        new InternalAnimationEvent(false, mMessage, this);
+    result->AssignAnimationEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  nsString mAnimationName;
+  nsString mPseudoElement;
+  float mElapsedTime;
+
+  void AssignAnimationEventData(const InternalAnimationEvent& aEvent,
+                                bool aCopyTargets) {
+    AssignEventData(aEvent, aCopyTargets);
+
+    mAnimationName = aEvent.mAnimationName;
+    mElapsedTime = aEvent.mElapsedTime;
+    mPseudoElement = aEvent.mPseudoElement;
+  }
+};
+
+/******************************************************************************
+ * mozilla::InternalSMILTimeEvent
+ ******************************************************************************/
+
+class InternalSMILTimeEvent : public InternalUIEvent {
+ public:
+  virtual InternalSMILTimeEvent* AsSMILTimeEvent() override { return this; }
+
+  InternalSMILTimeEvent(bool aIsTrusted, EventMessage aMessage,
+                        const WidgetEventTime* aTime = nullptr)
+      : InternalUIEvent(aIsTrusted, aMessage, eSMILTimeEventClass, aTime) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eSMILTimeEventClass,
+               "Duplicate() must be overridden by sub class");
+    InternalSMILTimeEvent* result =
+        new InternalSMILTimeEvent(false, mMessage, this);
+    result->AssignSMILTimeEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  void AssignSMILTimeEventData(const InternalSMILTimeEvent& aEvent,
+                               bool aCopyTargets) {
+    AssignUIEventData(aEvent, aCopyTargets);
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_ContentEvents_h__
diff --git a/widget/DimensionRequest.cpp b/widget/DimensionRequest.cpp
new file mode 100644
index 0000000000..4f2f667643
--- /dev/null
+++ b/widget/DimensionRequest.cpp
@@ -0,0 +1,120 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DimensionRequest.h"
+
+#include "nsIBaseWindow.h"
+#include "nsIDocShellTreeOwner.h"
+#include "mozilla/Try.h"
+
+namespace mozilla {
+
+nsresult DimensionRequest::SupplementFrom(nsIBaseWindow* aSource) {
+  NS_ENSURE_ARG_POINTER(aSource);
+  int32_t x = 0, y = 0, width = 0, height = 0;
+
+  bool needsPosition = mX.isSome() != mY.isSome();
+  bool needsSize = mWidth.isSome() != mHeight.isSome();
+
+  if (!needsPosition && !needsSize) {
+    return NS_OK;
+  }
+
+  MOZ_TRY(aSource->GetDimensions(mDimensionKind, needsPosition ? &x : nullptr,
+                                 needsPosition ? &y : nullptr,
+                                 needsSize ? &width : nullptr,
+                                 needsSize ? &height : nullptr));
+
+  if (needsPosition) {
+    if (mX.isNothing()) {
+      mX.emplace(x);
+    }
+    if (mY.isNothing()) {
+      mY.emplace(y);
+    }
+  }
+  if (needsSize) {
+    if (mWidth.isNothing()) {
+      mWidth.emplace(width);
+    }
+    if (mHeight.isNothing()) {
+      mHeight.emplace(height);
+    }
+  }
+
+  MOZ_ASSERT(mX.isSome() == mY.isSome());
+  MOZ_ASSERT(mWidth.isSome() == mHeight.isSome());
+  return NS_OK;
+}
+
+nsresult DimensionRequest::ApplyOuterTo(nsIBaseWindow* aTarget) {
+  NS_ENSURE_ARG_POINTER(aTarget);
+  MOZ_ASSERT(mX.isSome() == mY.isSome(),
+             "Missing dimensions should have been completed.");
+  MOZ_ASSERT(mWidth.isSome() == mHeight.isSome(),
+             "Missing dimensions should have been completed.");
+  if (mDimensionKind != DimensionKind::Outer) {
+    MOZ_ASSERT_UNREACHABLE("Expected outer dimensions.");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  bool havePosition = mX.isSome() && mY.isSome();
+  bool haveSize = mWidth.isSome() && mHeight.isSome();
+
+  if (!havePosition && !haveSize) {
+    return NS_OK;
+  }
+
+  if (havePosition && haveSize) {
+    return aTarget->SetPositionAndSize(*mX, *mY, *mWidth, *mHeight, true);
+  }
+
+  if (havePosition) {
+    return aTarget->SetPosition(*mX, *mY);
+  }
+
+  if (haveSize) {
+    return aTarget->SetSize(*mWidth, *mHeight, true);
+  }
+
+  MOZ_ASSERT_UNREACHABLE();
+  return NS_ERROR_UNEXPECTED;
+}
+
+nsresult DimensionRequest::ApplyInnerTo(nsIDocShellTreeOwner* aTarget,
+                                        bool aAsRootShell) {
+  NS_ENSURE_ARG_POINTER(aTarget);
+  MOZ_ASSERT(mX.isSome() == mY.isSome(),
+             "Missing dimensions should have been completed.");
+  MOZ_ASSERT(mWidth.isSome() == mHeight.isSome(),
+             "Missing dimensions should have been completed.");
+  if (mDimensionKind != DimensionKind::Inner) {
+    MOZ_ASSERT_UNREACHABLE("Expected inner dimensions.");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  bool havePosition = mX.isSome() && mY.isSome();
+  bool haveSize = mWidth.isSome() && mHeight.isSome();
+
+  if (!havePosition && !haveSize) {
+    return NS_OK;
+  }
+
+  if (havePosition) {
+    MOZ_ASSERT_UNREACHABLE("Inner position is not implemented.");
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  if (haveSize) {
+    if (aAsRootShell) {
+      return aTarget->SetRootShellSize(*mWidth, *mHeight);
+    }
+    return aTarget->SetPrimaryContentSize(*mWidth, *mHeight);
+  }
+
+  MOZ_ASSERT_UNREACHABLE();
+  return NS_ERROR_UNEXPECTED;
+}
+
+}  // namespace mozilla
diff --git a/widget/DimensionRequest.h b/widget/DimensionRequest.h
new file mode 100644
index 0000000000..75f5c96b45
--- /dev/null
+++ b/widget/DimensionRequest.h
@@ -0,0 +1,71 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_DimensionRequest_h
+#define mozilla_DimensionRequest_h
+
+#include "Units.h"
+#include "mozilla/Maybe.h"
+
+class nsIBaseWindow;
+class nsIDocShellTreeOwner;
+
+namespace mozilla {
+
+enum class DimensionKind { Inner, Outer };
+
+/**
+ * DimensionRequest allows to request the change of some dimensions without
+ * having to specify the unchanged dimensions. This is specifically necessary
+ * when a change is initiated from a child process, which might not have an
+ * up-to-date view of its latest dimensions. Having to specify the missing
+ * dimensions with an outdated view can revert a previous change.
+ *
+ * The following series of changes `window.screenX = 10; window.screenY = 10;`
+ * essentially translates into two moveTo() calls. For the second call we want
+ * to account for changes made by the first call. From a child process we would
+ * end up crafting the second call without knowing the results of the first
+ * call. In the parent process we have access to results of the first call
+ * before crafting the second one. Although on Linux even the parent process
+ * doesn't have immediate access to the results of the last change.
+ *
+ * Note: The concept of an inner position is not present on
+ * nsIDocShellTreeOwner and nsIBaseWindow. A request specifying an inner
+ * position will return an NS_ERROR_NOT_IMPLEMENTED.
+ */
+struct DimensionRequest {
+  DimensionKind mDimensionKind;
+  Maybe<LayoutDeviceIntCoord> mX;
+  Maybe<LayoutDeviceIntCoord> mY;
+  Maybe<LayoutDeviceIntCoord> mWidth;
+  Maybe<LayoutDeviceIntCoord> mHeight;
+
+  /**
+   * Fills the missing dimensions with values obtained from `aSource`. Whether
+   * inner dimensions are supported depends on the implementation of
+   * `nsIBaseWindow::GetDimensions` for `aSource`.
+   *
+   * @param aSource  The source for the missing dimensions.
+   */
+  nsresult SupplementFrom(nsIBaseWindow* aSource);
+
+  /**
+   * Changes the outer size and or position of `aTarget`. Only outer dimensions
+   * are supported.
+   *
+   * @param aTarget  The target whose size or position we want to change.
+   */
+  nsresult ApplyOuterTo(nsIBaseWindow* aTarget);
+
+  /**
+   * Changes the inner size of `aTarget`. Only inner dimensions are supported.
+   *
+   * @param aTarget  The target whose size we want to change.
+   */
+  nsresult ApplyInnerTo(nsIDocShellTreeOwner* aTarget, bool aAsRootShell);
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_DimensionRequest_h
diff --git a/widget/EventClassList.h b/widget/EventClassList.h
new file mode 100644
index 0000000000..c8870d84e5
--- /dev/null
+++ b/widget/EventClassList.h
@@ -0,0 +1,58 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This header file lists up all event classes and related structs.
+ * Define NS_EVENT_CLASS(aPrefix, aName) and NS_ROOT_EVENT_CLASS(aPrefix, aName)
+ * before including this.
+ * If an event name is WidgetInputEvent, aPrefix is "Widget" and aName is
+ * "InputEvent".  NS_ROOT_EVENT_CLASS() is only used for WidgetEvent for
+ * allowing special handling for it.  If you don't need such special handling,
+ * you can define it as:
+ * #define NS_ROOT_EVENT_CLASS(aPrefix, aName) NS_EVENT_CLASS(aPrefix, aName)
+ */
+
+// BasicEvents.h
+NS_ROOT_EVENT_CLASS(Widget, Event)
+NS_EVENT_CLASS(Widget, GUIEvent)
+NS_EVENT_CLASS(Widget, InputEvent)
+NS_EVENT_CLASS(Internal, UIEvent)
+
+// TextEvents.h
+NS_EVENT_CLASS(Widget, KeyboardEvent)
+NS_EVENT_CLASS(Widget, CompositionEvent)
+NS_EVENT_CLASS(Widget, QueryContentEvent)
+NS_EVENT_CLASS(Widget, SelectionEvent)
+NS_EVENT_CLASS(Internal, EditorInputEvent)
+
+// MouseEvents.h
+NS_EVENT_CLASS(Widget, MouseEventBase)
+NS_EVENT_CLASS(Widget, MouseEvent)
+NS_EVENT_CLASS(Widget, DragEvent)
+NS_EVENT_CLASS(Widget, MouseScrollEvent)
+NS_EVENT_CLASS(Widget, WheelEvent)
+NS_EVENT_CLASS(Widget, PointerEvent)
+
+// TouchEvents.h
+NS_EVENT_CLASS(Widget, GestureNotifyEvent)
+NS_EVENT_CLASS(Widget, SimpleGestureEvent)
+NS_EVENT_CLASS(Widget, TouchEvent)
+
+// ContentEvents.h
+NS_EVENT_CLASS(Internal, ScrollPortEvent)
+NS_EVENT_CLASS(Internal, ScrollAreaEvent)
+NS_EVENT_CLASS(Internal, FormEvent)
+NS_EVENT_CLASS(Internal, ClipboardEvent)
+NS_EVENT_CLASS(Internal, FocusEvent)
+NS_EVENT_CLASS(Internal, TransitionEvent)
+NS_EVENT_CLASS(Internal, AnimationEvent)
+NS_EVENT_CLASS(Internal, SMILTimeEvent)
+
+// MiscEvents.h
+NS_EVENT_CLASS(Widget, CommandEvent)
+NS_EVENT_CLASS(Widget, ContentCommandEvent)
+
+// InternalMutationEvent.h (dom/events)
+NS_EVENT_CLASS(Internal, MutationEvent)
diff --git a/widget/EventForwards.h b/widget/EventForwards.h
new file mode 100644
index 0000000000..e6a1ad6274
--- /dev/null
+++ b/widget/EventForwards.h
@@ -0,0 +1,497 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_EventForwards_h__
+#define mozilla_EventForwards_h__
+
+#include <stdint.h>
+
+#include "nsStringFwd.h"
+#include "nsTArray.h"
+
+#ifdef DEBUG
+#  include "mozilla/StaticPrefs_dom.h"
+#endif  // #ifdef DEBUG
+
+class nsCommandParams;
+
+/**
+ * XXX Following enums should be in BasicEvents.h.  However, currently, it's
+ *     impossible to use foward delearation for enum.
+ */
+
+/**
+ * Return status for event processors.
+ */
+enum nsEventStatus {
+  // The event is ignored, do default processing
+  nsEventStatus_eIgnore,
+  // The event is consumed, don't do default processing
+  nsEventStatus_eConsumeNoDefault,
+  // The event is consumed, but do default processing
+  nsEventStatus_eConsumeDoDefault,
+  // Value is not for use, only for serialization
+  nsEventStatus_eSentinel
+};
+
+namespace mozilla {
+
+enum class CanBubble { eYes, eNo };
+
+enum class Cancelable { eYes, eNo };
+
+enum class ChromeOnlyDispatch { eYes, eNo };
+
+enum class Trusted { eYes, eNo };
+
+enum class Composed { eYes, eNo, eDefault };
+
+/**
+ * Event messages
+ */
+
+typedef uint16_t EventMessageType;
+
+enum EventMessage : EventMessageType {
+
+#define NS_EVENT_MESSAGE(aMessage) aMessage,
+#define NS_EVENT_MESSAGE_FIRST_LAST(aMessage, aFirst, aLast) \
+  aMessage##First = aFirst, aMessage##Last = aLast,
+
+#include "mozilla/EventMessageList.h"
+
+#undef NS_EVENT_MESSAGE
+#undef NS_EVENT_MESSAGE_FIRST_LAST
+
+  // For preventing bustage due to "," after the last item.
+  eEventMessage_MaxValue
+};
+
+const char* ToChar(EventMessage aEventMessage);
+
+/**
+ * Event class IDs
+ */
+
+typedef uint8_t EventClassIDType;
+
+enum EventClassID : EventClassIDType {
+// The event class name will be:
+//   eBasicEventClass for WidgetEvent
+//   eFooEventClass for WidgetFooEvent or InternalFooEvent
+#define NS_ROOT_EVENT_CLASS(aPrefix, aName) eBasic##aName##Class
+#define NS_EVENT_CLASS(aPrefix, aName) , e##aName##Class
+
+#include "mozilla/EventClassList.h"
+
+#undef NS_EVENT_CLASS
+#undef NS_ROOT_EVENT_CLASS
+};
+
+const char* ToChar(EventClassID aEventClassID);
+
+typedef uint16_t Modifiers;
+
+#define NS_DEFINE_KEYNAME(aCPPName, aDOMKeyName) KEY_NAME_INDEX_##aCPPName,
+
+typedef uint16_t KeyNameIndexType;
+enum KeyNameIndex : KeyNameIndexType {
+#include "mozilla/KeyNameList.h"
+  // If a DOM keyboard event is synthesized by script, this is used.  Then,
+  // specified key name should be stored and use it as .key value.
+  KEY_NAME_INDEX_USE_STRING
+};
+
+#undef NS_DEFINE_KEYNAME
+
+const nsCString ToString(KeyNameIndex aKeyNameIndex);
+
+#define NS_DEFINE_PHYSICAL_KEY_CODE_NAME(aCPPName, aDOMCodeName) \
+  CODE_NAME_INDEX_##aCPPName,
+
+typedef uint8_t CodeNameIndexType;
+enum CodeNameIndex : CodeNameIndexType {
+#include "mozilla/PhysicalKeyCodeNameList.h"
+  // If a DOM keyboard event is synthesized by script, this is used.  Then,
+  // specified code name should be stored and use it as .code value.
+  CODE_NAME_INDEX_USE_STRING
+};
+
+#undef NS_DEFINE_PHYSICAL_KEY_CODE_NAME
+
+const nsCString ToString(CodeNameIndex aCodeNameIndex);
+
+#define NS_DEFINE_INPUTTYPE(aCPPName, aDOMName) e##aCPPName,
+
+typedef uint8_t EditorInputTypeType;
+enum class EditorInputType : EditorInputTypeType {
+#include "mozilla/InputTypeList.h"
+  // If a DOM input event is synthesized by script, this is used.  Then,
+  // specified input type should be stored as string and use it as .inputType
+  // value.
+  eUnknown,
+};
+
+#undef NS_DEFINE_INPUTTYPE
+
+inline bool ExposesClipboardDataOrDataTransfer(EditorInputType aInputType) {
+  switch (aInputType) {
+    case EditorInputType::eInsertFromPaste:
+    case EditorInputType::eInsertFromPasteAsQuotation:
+      return true;
+    default:
+      return false;
+  }
+}
+
+/**
+ * IsDataAvailableOnTextEditor() returns true if aInputType on TextEditor
+ * should have non-null InputEvent.data value.
+ */
+inline bool IsDataAvailableOnTextEditor(EditorInputType aInputType) {
+  switch (aInputType) {
+    case EditorInputType::eInsertText:
+    case EditorInputType::eInsertCompositionText:
+    case EditorInputType::eInsertFromComposition:  // Only level 2
+    case EditorInputType::eInsertFromPaste:
+    case EditorInputType::eInsertFromPasteAsQuotation:
+    case EditorInputType::eInsertTranspose:
+    case EditorInputType::eInsertFromDrop:
+    case EditorInputType::eInsertReplacementText:
+    case EditorInputType::eInsertFromYank:
+    case EditorInputType::eFormatSetBlockTextDirection:
+    case EditorInputType::eFormatSetInlineTextDirection:
+      return true;
+    default:
+      return false;
+  }
+}
+
+/**
+ * IsDataAvailableOnHTMLEditor() returns true if aInputType on HTMLEditor
+ * should have non-null InputEvent.data value.
+ */
+inline bool IsDataAvailableOnHTMLEditor(EditorInputType aInputType) {
+  switch (aInputType) {
+    case EditorInputType::eInsertText:
+    case EditorInputType::eInsertCompositionText:
+    case EditorInputType::eInsertFromComposition:  // Only level 2
+    case EditorInputType::eFormatSetBlockTextDirection:
+    case EditorInputType::eFormatSetInlineTextDirection:
+    case EditorInputType::eInsertLink:
+    case EditorInputType::eFormatBackColor:
+    case EditorInputType::eFormatFontColor:
+    case EditorInputType::eFormatFontName:
+      return true;
+    default:
+      return false;
+  }
+}
+
+/**
+ * IsDataTransferAvailableOnHTMLEditor() returns true if aInputType on
+ * HTMLEditor should have non-null InputEvent.dataTransfer value.
+ */
+inline bool IsDataTransferAvailableOnHTMLEditor(EditorInputType aInputType) {
+  switch (aInputType) {
+    case EditorInputType::eInsertFromPaste:
+    case EditorInputType::eInsertFromPasteAsQuotation:
+    case EditorInputType::eInsertFromDrop:
+    case EditorInputType::eInsertTranspose:
+    case EditorInputType::eInsertReplacementText:
+    case EditorInputType::eInsertFromYank:
+      return true;
+    default:
+      return false;
+  }
+}
+
+/**
+ * MayHaveTargetRangesOnHTMLEditor() returns true if "beforeinput" event whose
+ * whose inputType is aInputType on HTMLEditor may return non-empty static
+ * range array from getTargetRanges().
+ * Note that TextEditor always sets empty array.  Therefore, there is no
+ * method for TextEditor.
+ */
+inline bool MayHaveTargetRangesOnHTMLEditor(EditorInputType aInputType) {
+  switch (aInputType) {
+    // Explicitly documented by the specs.
+    case EditorInputType::eHistoryRedo:
+    case EditorInputType::eHistoryUndo:
+    // Not documented, but other browsers use empty array.
+    case EditorInputType::eFormatSetBlockTextDirection:
+      return false;
+    default:
+      return true;
+  }
+}
+
+/**
+ * IsCancelableBeforeInputEvent() returns true if `beforeinput` event for
+ * aInputType should be cancelable.
+ *
+ * Input Events Level 1:
+ *   https://rawgit.com/w3c/input-events/v1/index.html#x5-1-2-attributes
+ * Input Events Level 2:
+ *   https://w3c.github.io/input-events/#interface-InputEvent-Attributes
+ */
+inline bool IsCancelableBeforeInputEvent(EditorInputType aInputType) {
+  switch (aInputType) {
+    case EditorInputType::eInsertText:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eInsertReplacementText:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eInsertLineBreak:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eInsertParagraph:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eInsertOrderedList:
+      return true;
+    case EditorInputType::eInsertUnorderedList:
+      return true;
+    case EditorInputType::eInsertHorizontalRule:
+      return true;
+    case EditorInputType::eInsertFromYank:
+      return true;
+    case EditorInputType::eInsertFromDrop:
+      return true;
+    case EditorInputType::eInsertFromPaste:
+      return true;
+    case EditorInputType::eInsertFromPasteAsQuotation:
+      return true;
+    case EditorInputType::eInsertTranspose:
+      return true;
+    case EditorInputType::eInsertCompositionText:
+      return false;
+    case EditorInputType::eInsertFromComposition:
+      MOZ_ASSERT(!StaticPrefs::dom_input_events_conform_to_level_1());
+      return true;
+    case EditorInputType::eInsertLink:
+      return true;
+    case EditorInputType::eDeleteByComposition:
+      MOZ_ASSERT(!StaticPrefs::dom_input_events_conform_to_level_1());
+      return true;
+    case EditorInputType::eDeleteCompositionText:
+      MOZ_ASSERT(!StaticPrefs::dom_input_events_conform_to_level_1());
+      return false;
+    case EditorInputType::eDeleteWordBackward:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eDeleteWordForward:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eDeleteSoftLineBackward:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eDeleteSoftLineForward:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eDeleteEntireSoftLine:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eDeleteHardLineBackward:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eDeleteHardLineForward:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eDeleteByDrag:
+      return true;
+    case EditorInputType::eDeleteByCut:
+      return true;
+    case EditorInputType::eDeleteContent:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eDeleteContentBackward:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eDeleteContentForward:
+      return true;  // In Level 1, undefined.
+    case EditorInputType::eHistoryUndo:
+      return true;
+    case EditorInputType::eHistoryRedo:
+      return true;
+    case EditorInputType::eFormatBold:
+      return true;
+    case EditorInputType::eFormatItalic:
+      return true;
+    case EditorInputType::eFormatUnderline:
+      return true;
+    case EditorInputType::eFormatStrikeThrough:
+      return true;
+    case EditorInputType::eFormatSuperscript:
+      return true;
+    case EditorInputType::eFormatSubscript:
+      return true;
+    case EditorInputType::eFormatJustifyFull:
+      return true;
+    case EditorInputType::eFormatJustifyCenter:
+      return true;
+    case EditorInputType::eFormatJustifyRight:
+      return true;
+    case EditorInputType::eFormatJustifyLeft:
+      return true;
+    case EditorInputType::eFormatIndent:
+      return true;
+    case EditorInputType::eFormatOutdent:
+      return true;
+    case EditorInputType::eFormatRemove:
+      return true;
+    case EditorInputType::eFormatSetBlockTextDirection:
+      return true;
+    case EditorInputType::eFormatSetInlineTextDirection:
+      return true;
+    case EditorInputType::eFormatBackColor:
+      return true;
+    case EditorInputType::eFormatFontColor:
+      return true;
+    case EditorInputType::eFormatFontName:
+      return true;
+    case EditorInputType::eUnknown:
+      // This is not declared by Input Events, but it does not make sense to
+      // allow web apps to cancel default action without inputType value check.
+      // If some our specific edit actions should be cancelable, new inputType
+      // value for them should be declared by the spec.
+      return false;
+    default:
+      MOZ_ASSERT_UNREACHABLE("The new input type is not handled");
+      return false;
+  }
+}
+
+#define NS_DEFINE_COMMAND(aName, aCommandStr) , aName
+#define NS_DEFINE_COMMAND_WITH_PARAM(aName, aCommandStr, aParam) , aName
+#define NS_DEFINE_COMMAND_NO_EXEC_COMMAND(aName) , aName
+
+typedef uint8_t CommandInt;
+enum class Command : CommandInt {
+  DoNothing
+
+#include "mozilla/CommandList.h"
+};
+#undef NS_DEFINE_COMMAND
+#undef NS_DEFINE_COMMAND_WITH_PARAM
+#undef NS_DEFINE_COMMAND_NO_EXEC_COMMAND
+
+const char* ToChar(Command aCommand);
+
+/**
+ * Return a command value for aCommandName.
+ * XXX: Is there a better place to put `Command` related methods instead of
+ *      global scope in `mozilla` namespace?
+ *
+ * @param aCommandName          Should be a XUL command name like "cmd_bold"
+ *                              (case sensitive).
+ * @param aCommandparams        Additional parameter value of aCommandName.
+ *                              Can be nullptr, but if aCommandName requires
+ *                              additional parameter and sets this to nullptr,
+ *                              will return Command::DoNothing with warning.
+ */
+Command GetInternalCommand(const char* aCommandName,
+                           const nsCommandParams* aCommandParams = nullptr);
+
+}  // namespace mozilla
+
+/**
+ * All header files should include this header instead of *Events.h.
+ */
+
+namespace mozilla {
+
+template <class T>
+class OwningNonNull;
+
+namespace dom {
+class StaticRange;
+}
+
+#define NS_EVENT_CLASS(aPrefix, aName) class aPrefix##aName;
+#define NS_ROOT_EVENT_CLASS(aPrefix, aName) NS_EVENT_CLASS(aPrefix, aName)
+
+#include "mozilla/EventClassList.h"
+
+#undef NS_EVENT_CLASS
+#undef NS_ROOT_EVENT_CLASS
+
+// BasicEvents.h
+struct BaseEventFlags;
+struct EventFlags;
+
+class WidgetEventTime;
+
+// TextEvents.h
+enum class AccessKeyType;
+
+struct AlternativeCharCode;
+struct ShortcutKeyCandidate;
+
+typedef nsTArray<ShortcutKeyCandidate> ShortcutKeyCandidateArray;
+typedef AutoTArray<ShortcutKeyCandidate, 10> AutoShortcutKeyCandidateArray;
+
+// TextRange.h
+typedef uint8_t RawTextRangeType;
+enum class TextRangeType : RawTextRangeType;
+
+struct TextRangeStyle;
+struct TextRange;
+
+class EditCommands;
+class TextRangeArray;
+
+typedef nsTArray<OwningNonNull<dom::StaticRange>> OwningNonNullStaticRangeArray;
+
+// FontRange.h
+struct FontRange;
+
+enum MouseButton : int16_t {
+  eNotPressed = -1,
+  ePrimary = 0,
+  eMiddle = 1,
+  eSecondary = 2,
+  eX1 = 3,  // Typically, "back" button
+  eX2 = 4,  // Typically, "forward" button
+  eEraser = 5
+};
+
+enum MouseButtonsFlag {
+  eNoButtons = 0x00,
+  ePrimaryFlag = 0x01,
+  eSecondaryFlag = 0x02,
+  eMiddleFlag = 0x04,
+  // typicall, "back" button being left side of 5-button
+  // mice, see "buttons" attribute document of DOM3 Events.
+  e4thFlag = 0x08,
+  // typicall, "forward" button being right side of 5-button
+  // mice, see "buttons" attribute document of DOM3 Events.
+  e5thFlag = 0x10,
+  eEraserFlag = 0x20
+};
+
+/**
+ * Returns a MouseButtonsFlag value which is changed by a button state change
+ * event whose mButton is aMouseButton.
+ */
+inline MouseButtonsFlag MouseButtonsFlagToChange(MouseButton aMouseButton) {
+  switch (aMouseButton) {
+    case MouseButton::ePrimary:
+      return MouseButtonsFlag::ePrimaryFlag;
+    case MouseButton::eMiddle:
+      return MouseButtonsFlag::eMiddleFlag;
+    case MouseButton::eSecondary:
+      return MouseButtonsFlag::eSecondaryFlag;
+    case MouseButton::eX1:
+      return MouseButtonsFlag::e4thFlag;
+    case MouseButton::eX2:
+      return MouseButtonsFlag::e5thFlag;
+    case MouseButton::eEraser:
+      return MouseButtonsFlag::eEraserFlag;
+    default:
+      return MouseButtonsFlag::eNoButtons;
+  }
+}
+
+enum class TextRangeType : RawTextRangeType;
+
+// IMEData.h
+
+template <typename IntType>
+class StartAndEndOffsets;
+template <typename IntType>
+class OffsetAndData;
+
+}  // namespace mozilla
+
+#endif  // mozilla_EventForwards_h__
diff --git a/widget/EventMessageList.h b/widget/EventMessageList.h
new file mode 100644
index 0000000000..ae02d04676
--- /dev/null
+++ b/widget/EventMessageList.h
@@ -0,0 +1,459 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This header file lists up all event messages.
+ * Before including this header file, you should define:
+ * NS_EVENT_MESSAGE(aMessage)
+ *
+ * Additionally, you can specify following macro for e*First and e*Last.
+ * NS_EVENT_MESSAGE_FIRST_LAST(aMessage, aFirst, aLast)
+ * This is optional, if you need only actual event messages, you don't need
+ * to define this macro.
+ *
+ * Naming rules of the event messages:
+ * 0. Starting with "e" prefix and use camelcase.
+ * 1. Basically, use same name as the DOM name which is fired at dispatching
+ *    the event.
+ * 2. If the event message name becomes too generic, e.g., "eInvalid", that may
+ *    conflict with another enum's item name, append something after the "e"
+ *    prefix, e.g., "eFormInvalid".
+ */
+
+#ifndef NS_EVENT_MESSAGE_FIRST_LAST
+#  define UNDEF_NS_EVENT_MESSAGE_FIRST_LAST 1
+#  define NS_EVENT_MESSAGE_FIRST_LAST(aMessage, aFirst, aLast)
+#endif
+
+NS_EVENT_MESSAGE(eVoidEvent)
+
+// This is a dummy event message for all event listener implementation in
+// EventListenerManager.
+NS_EVENT_MESSAGE(eAllEvents)
+
+NS_EVENT_MESSAGE(eKeyPress)
+NS_EVENT_MESSAGE(eKeyUp)
+NS_EVENT_MESSAGE(eKeyDown)
+
+// This message is sent after a content process handles a key event or accesskey
+// to indicate that an potential accesskey was not found. The parent process may
+// then respond by, for example, opening menus and processing other shortcuts.
+// It inherits its properties from a keypress event.
+NS_EVENT_MESSAGE(eAccessKeyNotFound)
+
+NS_EVENT_MESSAGE(eResize)
+NS_EVENT_MESSAGE(eScroll)
+NS_EVENT_MESSAGE(eMozVisualResize)
+NS_EVENT_MESSAGE(eMozVisualScroll)
+
+NS_EVENT_MESSAGE(eOffline)
+NS_EVENT_MESSAGE(eOnline)
+
+NS_EVENT_MESSAGE(eLanguageChange)
+
+NS_EVENT_MESSAGE(eMouseMove)
+NS_EVENT_MESSAGE(eMouseUp)
+NS_EVENT_MESSAGE(eMouseDown)
+NS_EVENT_MESSAGE(eMouseEnterIntoWidget)
+NS_EVENT_MESSAGE(eMouseExitFromWidget)
+NS_EVENT_MESSAGE(eMouseDoubleClick)
+NS_EVENT_MESSAGE(eMouseClick)
+NS_EVENT_MESSAGE(eMouseAuxClick)
+// eMouseActivate is fired when the widget is activated by a click.
+NS_EVENT_MESSAGE(eMouseActivate)
+NS_EVENT_MESSAGE(eMouseOver)
+NS_EVENT_MESSAGE(eMouseOut)
+NS_EVENT_MESSAGE(eMouseHitTest)
+NS_EVENT_MESSAGE(eMouseEnter)
+NS_EVENT_MESSAGE(eMouseLeave)
+NS_EVENT_MESSAGE(eMouseTouchDrag)
+NS_EVENT_MESSAGE(eMouseLongTap)
+NS_EVENT_MESSAGE(eMouseExploreByTouch)
+NS_EVENT_MESSAGE_FIRST_LAST(eMouseEvent, eMouseMove, eMouseExploreByTouch)
+
+// Pointer spec events
+NS_EVENT_MESSAGE(ePointerMove)
+NS_EVENT_MESSAGE(ePointerUp)
+NS_EVENT_MESSAGE(ePointerDown)
+NS_EVENT_MESSAGE(ePointerOver)
+NS_EVENT_MESSAGE(ePointerOut)
+NS_EVENT_MESSAGE(ePointerEnter)
+NS_EVENT_MESSAGE(ePointerLeave)
+NS_EVENT_MESSAGE(ePointerCancel)
+NS_EVENT_MESSAGE(ePointerGotCapture)
+NS_EVENT_MESSAGE(ePointerLostCapture)
+NS_EVENT_MESSAGE_FIRST_LAST(ePointerEvent, ePointerMove, ePointerLostCapture)
+
+NS_EVENT_MESSAGE(eContextMenu)
+
+NS_EVENT_MESSAGE(eCueChange)
+
+NS_EVENT_MESSAGE(eBeforeToggle)
+
+NS_EVENT_MESSAGE(eLoad)
+NS_EVENT_MESSAGE(eUnload)
+NS_EVENT_MESSAGE(eHashChange)
+NS_EVENT_MESSAGE(eImageAbort)
+NS_EVENT_MESSAGE(eLoadError)
+NS_EVENT_MESSAGE(eLoadEnd)
+NS_EVENT_MESSAGE(ePopState)
+NS_EVENT_MESSAGE(eRejectionHandled)
+NS_EVENT_MESSAGE(eStorage)
+NS_EVENT_MESSAGE(eUnhandledRejection)
+NS_EVENT_MESSAGE(eBeforeUnload)
+NS_EVENT_MESSAGE(eReadyStateChange)
+
+NS_EVENT_MESSAGE(eFormSubmit)
+NS_EVENT_MESSAGE(eFormReset)
+NS_EVENT_MESSAGE(eFormChange)
+NS_EVENT_MESSAGE(eFormSelect)
+NS_EVENT_MESSAGE(eFormInvalid)
+NS_EVENT_MESSAGE(eFormCheckboxStateChange)
+NS_EVENT_MESSAGE(eFormRadioStateChange)
+NS_EVENT_MESSAGE(eFormData)
+
+// Need separate focus/blur notifications for non-native widgets
+NS_EVENT_MESSAGE(eFocus)
+NS_EVENT_MESSAGE(eBlur)
+NS_EVENT_MESSAGE(eFocusIn)
+NS_EVENT_MESSAGE(eFocusOut)
+
+NS_EVENT_MESSAGE(eDragEnter)
+NS_EVENT_MESSAGE(eDragOver)
+NS_EVENT_MESSAGE(eDragExit)
+NS_EVENT_MESSAGE(eDrag)
+NS_EVENT_MESSAGE(eDragEnd)
+NS_EVENT_MESSAGE(eDragStart)
+NS_EVENT_MESSAGE(eDrop)
+NS_EVENT_MESSAGE(eDragLeave)
+NS_EVENT_MESSAGE_FIRST_LAST(eDragDropEvent, eDragEnter, eDragLeave)
+
+// XUL specific events
+NS_EVENT_MESSAGE(eXULPopupShowing)
+NS_EVENT_MESSAGE(eXULPopupShown)
+NS_EVENT_MESSAGE(eXULPopupHiding)
+NS_EVENT_MESSAGE(eXULPopupHidden)
+NS_EVENT_MESSAGE(eXULBroadcast)
+NS_EVENT_MESSAGE(eXULCommandUpdate)
+NS_EVENT_MESSAGE(eXULSystemStatusBarClick)
+
+// Legacy mouse scroll (wheel) events
+NS_EVENT_MESSAGE(eLegacyMouseLineOrPageScroll)
+NS_EVENT_MESSAGE(eLegacyMousePixelScroll)
+
+NS_EVENT_MESSAGE(eScrollPortUnderflow)
+NS_EVENT_MESSAGE(eScrollPortOverflow)
+
+NS_EVENT_MESSAGE(eLegacySubtreeModified)
+NS_EVENT_MESSAGE(eLegacyNodeInserted)
+NS_EVENT_MESSAGE(eLegacyNodeRemoved)
+NS_EVENT_MESSAGE(eLegacyNodeRemovedFromDocument)
+NS_EVENT_MESSAGE(eLegacyNodeInsertedIntoDocument)
+NS_EVENT_MESSAGE(eLegacyAttrModified)
+NS_EVENT_MESSAGE(eLegacyCharacterDataModified)
+NS_EVENT_MESSAGE_FIRST_LAST(eLegacyMutationEvent, eLegacySubtreeModified,
+                            eLegacyCharacterDataModified)
+
+NS_EVENT_MESSAGE(eUnidentifiedEvent)
+
+// composition events
+NS_EVENT_MESSAGE(eCompositionStart)
+// eCompositionEnd is the message for DOM compositionend event.
+// This event should NOT be dispatched from widget if eCompositionCommit
+// is available.
+NS_EVENT_MESSAGE(eCompositionEnd)
+// eCompositionUpdate is the message for DOM compositionupdate event.
+// This event should NOT be dispatched from widget since it will be dispatched
+// by mozilla::TextComposition automatically if eCompositionChange event
+// will change composition string.
+NS_EVENT_MESSAGE(eCompositionUpdate)
+// eCompositionChange is the message for representing a change of
+// composition string.  This should be dispatched from widget even if
+// composition string isn't changed but the ranges are changed.  This causes
+// a DOM "text" event which is a non-standard DOM event.
+NS_EVENT_MESSAGE(eCompositionChange)
+// eCompositionCommitAsIs is the message for representing a commit of
+// composition string.  TextComposition will commit composition with the
+// last data.  TextComposition will dispatch this event to the DOM tree as
+// eCompositionChange without clause information.  After that,
+// eCompositionEnd will be dispatched automatically.
+// Its mData and mRanges should be empty and nullptr.
+NS_EVENT_MESSAGE(eCompositionCommitAsIs)
+// eCompositionCommit is the message for representing a commit of
+// composition string with its mData value.  TextComposition will dispatch this
+// event to the DOM tree as eCompositionChange without clause information.
+// After that, eCompositionEnd will be dispatched automatically.
+// Its mRanges should be nullptr.
+NS_EVENT_MESSAGE(eCompositionCommit)
+// eCompositionCommitRequestHandled is NOT used with any Widget*Event.
+// This is used only by PBrowser.OnEventNeedingAckHandled().  If active IME
+// commits composition synchronously, BrowserParent returns the commit string
+// to the remote process synchronously.  Then, BrowserChild dispatches
+// eCompositionCommit in the remote process.  Finally, this message is sent
+// to BrowserParent.  (If IME commits composition asynchronously, this message
+// is not used.)
+NS_EVENT_MESSAGE(eCompositionCommitRequestHandled)
+
+// Following events are defined for deprecated DOM events which are using
+// InternalUIEvent class.
+// DOMActivate (mapped with the DOM event and used internally)
+NS_EVENT_MESSAGE(eLegacyDOMActivate)
+// DOMFocusIn (only mapped with the DOM event)
+NS_EVENT_MESSAGE(eLegacyDOMFocusIn)
+// DOMFocusOut (only mapped with the DOM event)
+NS_EVENT_MESSAGE(eLegacyDOMFocusOut)
+
+// pagetransition events
+NS_EVENT_MESSAGE(ePageShow)
+NS_EVENT_MESSAGE(ePageHide)
+
+// SVG events
+NS_EVENT_MESSAGE(eSVGLoad)
+NS_EVENT_MESSAGE(eSVGScroll)
+
+// XUL command events
+NS_EVENT_MESSAGE(eXULCommand)
+
+// Cut, copy, paste events
+NS_EVENT_MESSAGE(eCopy)
+NS_EVENT_MESSAGE(eCut)
+NS_EVENT_MESSAGE(ePaste)
+NS_EVENT_MESSAGE(ePasteNoFormatting)
+
+// Query for the selected text information, it return the selection offset,
+// selection length and selected text.
+NS_EVENT_MESSAGE(eQuerySelectedText)
+// Query for the text content of specified range, it returns actual lengh (if
+// the specified range is too long) and the text of the specified range.
+// Returns the entire text if requested length > actual length.
+NS_EVENT_MESSAGE(eQueryTextContent)
+// Query for the caret rect of nth insertion point. The offset of the result is
+// relative position from the top level widget.
+NS_EVENT_MESSAGE(eQueryCaretRect)
+// Query for the bounding rect of a range of characters. This works on any
+// valid character range given offset and length. Result is relative to top
+// level widget coordinates
+NS_EVENT_MESSAGE(eQueryTextRect)
+// Query for the bounding rect array of a range of characters.
+// Thiis similar event of eQueryTextRect.
+NS_EVENT_MESSAGE(eQueryTextRectArray)
+// Query for the bounding rect of the current focused frame. Result is relative
+// to top level widget coordinates
+NS_EVENT_MESSAGE(eQueryEditorRect)
+// Query for the current state of the content. The particular members of
+// mReply that are set for each query content event will be valid on success.
+NS_EVENT_MESSAGE(eQueryContentState)
+// Query for the selection in the form of a nsITransferable.
+NS_EVENT_MESSAGE(eQuerySelectionAsTransferable)
+// Query for character at a point.  This returns the character offset, its
+// rect and also tentative caret point if the point is clicked.  The point is
+// specified by Event::mRefPoint.
+NS_EVENT_MESSAGE(eQueryCharacterAtPoint)
+// Query if the DOM element under Event::mRefPoint belongs to our widget
+// or not.
+NS_EVENT_MESSAGE(eQueryDOMWidgetHittest)
+
+// Video events
+NS_EVENT_MESSAGE(eLoadStart)
+NS_EVENT_MESSAGE(eProgress)
+NS_EVENT_MESSAGE(eSuspend)
+NS_EVENT_MESSAGE(eEmptied)
+NS_EVENT_MESSAGE(eStalled)
+NS_EVENT_MESSAGE(ePlay)
+NS_EVENT_MESSAGE(ePause)
+NS_EVENT_MESSAGE(eLoadedMetaData)
+NS_EVENT_MESSAGE(eLoadedData)
+NS_EVENT_MESSAGE(eWaiting)
+NS_EVENT_MESSAGE(ePlaying)
+NS_EVENT_MESSAGE(eCanPlay)
+NS_EVENT_MESSAGE(eCanPlayThrough)
+NS_EVENT_MESSAGE(eSeeking)
+NS_EVENT_MESSAGE(eSeeked)
+NS_EVENT_MESSAGE(eTimeUpdate)
+NS_EVENT_MESSAGE(eEnded)
+NS_EVENT_MESSAGE(eRateChange)
+NS_EVENT_MESSAGE(eDurationChange)
+NS_EVENT_MESSAGE(eVolumeChange)
+
+// paint notification events
+NS_EVENT_MESSAGE(eAfterPaint)
+
+// Simple gesture events
+NS_EVENT_MESSAGE(eSwipeGestureMayStart)
+NS_EVENT_MESSAGE(eSwipeGestureStart)
+NS_EVENT_MESSAGE(eSwipeGestureUpdate)
+NS_EVENT_MESSAGE(eSwipeGestureEnd)
+NS_EVENT_MESSAGE(eSwipeGesture)
+NS_EVENT_MESSAGE(eMagnifyGestureStart)
+NS_EVENT_MESSAGE(eMagnifyGestureUpdate)
+NS_EVENT_MESSAGE(eMagnifyGesture)
+NS_EVENT_MESSAGE(eRotateGestureStart)
+NS_EVENT_MESSAGE(eRotateGestureUpdate)
+NS_EVENT_MESSAGE(eRotateGesture)
+NS_EVENT_MESSAGE(eTapGesture)
+NS_EVENT_MESSAGE(ePressTapGesture)
+NS_EVENT_MESSAGE(eEdgeUIStarted)
+NS_EVENT_MESSAGE(eEdgeUICanceled)
+NS_EVENT_MESSAGE(eEdgeUICompleted)
+
+// Events to manipulate selection (WidgetSelectionEvent)
+// Clear any previous selection and set the given range as the selection
+NS_EVENT_MESSAGE(eSetSelection)
+
+// Events of commands for the contents
+NS_EVENT_MESSAGE(eContentCommandCut)
+NS_EVENT_MESSAGE(eContentCommandCopy)
+NS_EVENT_MESSAGE(eContentCommandPaste)
+NS_EVENT_MESSAGE(eContentCommandDelete)
+NS_EVENT_MESSAGE(eContentCommandUndo)
+NS_EVENT_MESSAGE(eContentCommandRedo)
+// eContentCommandInsertText tries to insert text with replacing selection
+// in focused editor.
+NS_EVENT_MESSAGE(eContentCommandInsertText)
+NS_EVENT_MESSAGE(eContentCommandPasteTransferable)
+NS_EVENT_MESSAGE(eContentCommandLookUpDictionary)
+// eContentCommandScroll scrolls the nearest scrollable element to the
+// currently focused content or latest DOM selection. This would normally be
+// the same element scrolled by keyboard scroll commands, except that this event
+// will scroll an element scrollable in either direction.  I.e., if the nearest
+// scrollable ancestor element can only be scrolled vertically, and horizontal
+// scrolling is requested using this event, no scrolling will occur.
+NS_EVENT_MESSAGE(eContentCommandScroll)
+
+// Event to gesture notification
+NS_EVENT_MESSAGE(eGestureNotify)
+
+NS_EVENT_MESSAGE(eScrolledAreaChanged)
+
+// CSS Transition & Animation events:
+NS_EVENT_MESSAGE(eTransitionStart)
+NS_EVENT_MESSAGE(eTransitionRun)
+NS_EVENT_MESSAGE(eTransitionEnd)
+NS_EVENT_MESSAGE(eTransitionCancel)
+NS_EVENT_MESSAGE(eAnimationStart)
+NS_EVENT_MESSAGE(eAnimationEnd)
+NS_EVENT_MESSAGE(eAnimationIteration)
+NS_EVENT_MESSAGE(eAnimationCancel)
+
+// Webkit-prefixed versions of Transition & Animation events, for web compat:
+NS_EVENT_MESSAGE(eWebkitTransitionEnd)
+NS_EVENT_MESSAGE(eWebkitAnimationStart)
+NS_EVENT_MESSAGE(eWebkitAnimationEnd)
+NS_EVENT_MESSAGE(eWebkitAnimationIteration)
+
+NS_EVENT_MESSAGE(eSMILBeginEvent)
+NS_EVENT_MESSAGE(eSMILEndEvent)
+NS_EVENT_MESSAGE(eSMILRepeatEvent)
+
+NS_EVENT_MESSAGE(eAudioProcess)
+NS_EVENT_MESSAGE(eAudioComplete)
+
+// script notification events
+NS_EVENT_MESSAGE(eBeforeScriptExecute)
+NS_EVENT_MESSAGE(eAfterScriptExecute)
+
+NS_EVENT_MESSAGE(eBeforePrint)
+NS_EVENT_MESSAGE(eAfterPrint)
+
+NS_EVENT_MESSAGE(eMessage)
+NS_EVENT_MESSAGE(eMessageError)
+NS_EVENT_MESSAGE(eRTCTransform)
+
+// Menu open event
+NS_EVENT_MESSAGE(eOpen)
+
+// Device motion and orientation
+NS_EVENT_MESSAGE(eDeviceOrientation)
+NS_EVENT_MESSAGE(eDeviceOrientationAbsolute)
+NS_EVENT_MESSAGE(eDeviceMotion)
+NS_EVENT_MESSAGE(eUserProximity)
+NS_EVENT_MESSAGE(eDeviceLight)
+#if defined(MOZ_WIDGET_ANDROID)
+NS_EVENT_MESSAGE(eOrientationChange)
+#endif
+
+// WebVR events
+NS_EVENT_MESSAGE(eVRDisplayActivate)
+NS_EVENT_MESSAGE(eVRDisplayDeactivate)
+NS_EVENT_MESSAGE(eVRDisplayConnect)
+NS_EVENT_MESSAGE(eVRDisplayDisconnect)
+NS_EVENT_MESSAGE(eVRDisplayPresentChange)
+
+// Fullscreen DOM API
+NS_EVENT_MESSAGE(eFullscreenChange)
+NS_EVENT_MESSAGE(eFullscreenError)
+NS_EVENT_MESSAGE(eMozFullscreenChange)
+NS_EVENT_MESSAGE(eMozFullscreenError)
+
+NS_EVENT_MESSAGE(eTouchStart)
+NS_EVENT_MESSAGE(eTouchMove)
+NS_EVENT_MESSAGE(eTouchEnd)
+NS_EVENT_MESSAGE(eTouchCancel)
+NS_EVENT_MESSAGE(eTouchPointerCancel)
+
+// Pointerlock DOM API
+NS_EVENT_MESSAGE(ePointerLockChange)
+NS_EVENT_MESSAGE(ePointerLockError)
+NS_EVENT_MESSAGE(eMozPointerLockChange)
+NS_EVENT_MESSAGE(eMozPointerLockError)
+
+// eWheel is the event message of DOM wheel event.
+NS_EVENT_MESSAGE(eWheel)
+// eWheelOperationStart may be dispatched when user starts to operate mouse
+// wheel.  This won't be fired on some platforms which don't have corresponding
+// native event.
+NS_EVENT_MESSAGE(eWheelOperationStart)
+// eWheelOperationEnd may be dispatched when user ends or cancels operating
+// mouse wheel.  This won't be fired on some platforms which don't have
+// corresponding native event.
+NS_EVENT_MESSAGE(eWheelOperationEnd)
+
+// MediaRecorder events.
+NS_EVENT_MESSAGE(eMediaRecorderDataAvailable)
+NS_EVENT_MESSAGE(eMediaRecorderWarning)
+NS_EVENT_MESSAGE(eMediaRecorderStop)
+
+// Gamepad input events
+NS_EVENT_MESSAGE(eGamepadButtonDown)
+NS_EVENT_MESSAGE(eGamepadButtonUp)
+NS_EVENT_MESSAGE(eGamepadAxisMove)
+NS_EVENT_MESSAGE(eGamepadConnected)
+NS_EVENT_MESSAGE(eGamepadDisconnected)
+NS_EVENT_MESSAGE_FIRST_LAST(eGamepadEvent, eGamepadButtonDown,
+                            eGamepadDisconnected)
+
+// input and beforeinput events.
+NS_EVENT_MESSAGE(eEditorInput)
+NS_EVENT_MESSAGE(eEditorBeforeInput)
+
+// selection events
+NS_EVENT_MESSAGE(eSelectStart)
+NS_EVENT_MESSAGE(eSelectionChange)
+NS_EVENT_MESSAGE(eSlotChange)
+
+// visibility change
+NS_EVENT_MESSAGE(eVisibilityChange)
+
+// security policy events
+NS_EVENT_MESSAGE(eSecurityPolicyViolation)
+
+// Details element events.
+NS_EVENT_MESSAGE(eToggle)
+
+// Dialog element events.
+NS_EVENT_MESSAGE(eClose)
+NS_EVENT_MESSAGE(eCancel)
+
+// Marquee element events.
+NS_EVENT_MESSAGE(eMarqueeBounce)
+NS_EVENT_MESSAGE(eMarqueeStart)
+NS_EVENT_MESSAGE(eMarqueeFinish)
+
+NS_EVENT_MESSAGE(eScrollend)
+
+#ifdef UNDEF_NS_EVENT_MESSAGE_FIRST_LAST
+#  undef UNDEF_NS_EVENT_MESSAGE_FIRST_LAST
+#  undef NS_EVENT_MESSAGE_FIRST_LAST
+#endif
diff --git a/widget/FontRange.h b/widget/FontRange.h
new file mode 100644
index 0000000000..e5ee079a62
--- /dev/null
+++ b/widget/FontRange.h
@@ -0,0 +1,24 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_FontRange_h_
+#define mozilla_FontRange_h_
+
+#include "gfxTypes.h"  // for gfxFloat
+
+namespace mozilla {
+
+struct FontRange {
+  FontRange() : mStartOffset(0), mFontSize(0) {}
+
+  int32_t mStartOffset;
+  nsString mFontName;
+  gfxFloat mFontSize;  // in device pixels
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_FontRange_h_
diff --git a/widget/GfxDriverInfo.cpp b/widget/GfxDriverInfo.cpp
new file mode 100644
index 0000000000..d60b023ddc
--- /dev/null
+++ b/widget/GfxDriverInfo.cpp
@@ -0,0 +1,777 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GfxDriverInfo.h"
+
+#include "nsIGfxInfo.h"
+#include "nsTArray.h"
+#include "nsUnicharUtils.h"
+
+using namespace mozilla::widget;
+
+GfxDeviceFamily*
+    GfxDriverInfo::sDeviceFamilies[static_cast<size_t>(DeviceFamily::Max)];
+nsString*
+    GfxDriverInfo::sWindowProtocol[static_cast<size_t>(WindowProtocol::Max)];
+nsString* GfxDriverInfo::sDeviceVendors[static_cast<size_t>(DeviceVendor::Max)];
+nsString* GfxDriverInfo::sDriverVendors[static_cast<size_t>(DriverVendor::Max)];
+
+GfxDriverInfo::GfxDriverInfo()
+    : mOperatingSystem(OperatingSystem::Unknown),
+      mOperatingSystemVersion(0),
+      mScreen(ScreenSizeStatus::All),
+      mBattery(BatteryStatus::All),
+      mWindowProtocol(GfxDriverInfo::GetWindowProtocol(WindowProtocol::All)),
+      mAdapterVendor(GfxDriverInfo::GetDeviceVendor(DeviceFamily::All)),
+      mDriverVendor(GfxDriverInfo::GetDriverVendor(DriverVendor::All)),
+      mDevices(GfxDriverInfo::GetDeviceFamily(DeviceFamily::All)),
+      mDeleteDevices(false),
+      mFeature(optionalFeatures),
+      mFeatureStatus(nsIGfxInfo::FEATURE_STATUS_OK),
+      mComparisonOp(DRIVER_COMPARISON_IGNORED),
+      mDriverVersion(0),
+      mDriverVersionMax(0),
+      mSuggestedVersion(nullptr),
+      mRuleId(nullptr),
+      mGpu2(false) {}
+
+GfxDriverInfo::GfxDriverInfo(
+    OperatingSystem os, ScreenSizeStatus screen, BatteryStatus battery,
+    const nsAString& windowProtocol, const nsAString& vendor,
+    const nsAString& driverVendor, GfxDeviceFamily* devices, int32_t feature,
+    int32_t featureStatus, VersionComparisonOp op, uint64_t driverVersion,
+    const char* ruleId, const char* suggestedVersion /* = nullptr */,
+    bool ownDevices /* = false */, bool gpu2 /* = false */)
+    : mOperatingSystem(os),
+      mOperatingSystemVersion(0),
+      mScreen(screen),
+      mBattery(battery),
+      mWindowProtocol(windowProtocol),
+      mAdapterVendor(vendor),
+      mDriverVendor(driverVendor),
+      mDevices(devices),
+      mDeleteDevices(ownDevices),
+      mFeature(feature),
+      mFeatureStatus(featureStatus),
+      mComparisonOp(op),
+      mDriverVersion(driverVersion),
+      mDriverVersionMax(0),
+      mSuggestedVersion(suggestedVersion),
+      mRuleId(ruleId),
+      mGpu2(gpu2) {}
+
+GfxDriverInfo::GfxDriverInfo(const GfxDriverInfo& aOrig)
+    : mOperatingSystem(aOrig.mOperatingSystem),
+      mOperatingSystemVersion(aOrig.mOperatingSystemVersion),
+      mScreen(aOrig.mScreen),
+      mBattery(aOrig.mBattery),
+      mWindowProtocol(aOrig.mWindowProtocol),
+      mAdapterVendor(aOrig.mAdapterVendor),
+      mDriverVendor(aOrig.mDriverVendor),
+      mFeature(aOrig.mFeature),
+      mFeatureStatus(aOrig.mFeatureStatus),
+      mComparisonOp(aOrig.mComparisonOp),
+      mDriverVersion(aOrig.mDriverVersion),
+      mDriverVersionMax(aOrig.mDriverVersionMax),
+      mSuggestedVersion(aOrig.mSuggestedVersion),
+      mRuleId(aOrig.mRuleId),
+      mGpu2(aOrig.mGpu2) {
+  // If we're managing the lifetime of the device family, we have to make a
+  // copy of the original's device family.
+  if (aOrig.mDeleteDevices && aOrig.mDevices) {
+    GfxDeviceFamily* devices = new GfxDeviceFamily;
+    *devices = *aOrig.mDevices;
+    mDevices = devices;
+  } else {
+    mDevices = aOrig.mDevices;
+  }
+
+  mDeleteDevices = aOrig.mDeleteDevices;
+}
+
+GfxDriverInfo::~GfxDriverInfo() {
+  if (mDeleteDevices) {
+    delete mDevices;
+  }
+}
+
+void GfxDeviceFamily::Append(const nsAString& aDeviceId) {
+  mIds.AppendElement(aDeviceId);
+}
+
+void GfxDeviceFamily::AppendRange(int32_t aBeginDeviceId,
+                                  int32_t aEndDeviceId) {
+  mRanges.AppendElement(
+      GfxDeviceFamily::DeviceRange{aBeginDeviceId, aEndDeviceId});
+}
+
+nsresult GfxDeviceFamily::Contains(nsAString& aDeviceId) const {
+  for (const auto& id : mIds) {
+    if (id.Equals(aDeviceId, nsCaseInsensitiveStringComparator)) {
+      return NS_OK;
+    }
+  }
+
+  if (mRanges.IsEmpty()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsresult valid = NS_OK;
+  int32_t deviceId = aDeviceId.ToInteger(&valid, 16);
+  if (valid != NS_OK) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  for (const auto& range : mRanges) {
+    if (deviceId >= range.mBegin && deviceId <= range.mEnd) {
+      return NS_OK;
+    }
+  }
+
+  return NS_ERROR_NOT_AVAILABLE;
+}
+
+// Macros for appending a device to the DeviceFamily.
+#define APPEND_DEVICE(device) APPEND_DEVICE2(#device)
+#define APPEND_DEVICE2(device) \
+  deviceFamily->Append(NS_LITERAL_STRING_FROM_CSTRING(device))
+#define APPEND_RANGE(start, end) deviceFamily->AppendRange(start, end)
+
+const GfxDeviceFamily* GfxDriverInfo::GetDeviceFamily(DeviceFamily id) {
+  if (id >= DeviceFamily::Max) {
+    MOZ_ASSERT_UNREACHABLE("DeviceFamily id is out of range");
+    return nullptr;
+  }
+
+  // All of these have no specific device ID filtering.
+  switch (id) {
+    case DeviceFamily::All:
+    case DeviceFamily::IntelAll:
+    case DeviceFamily::NvidiaAll:
+    case DeviceFamily::AtiAll:
+    case DeviceFamily::MicrosoftAll:
+    case DeviceFamily::ParallelsAll:
+    case DeviceFamily::QualcommAll:
+    case DeviceFamily::AppleAll:
+    case DeviceFamily::AmazonAll:
+      return nullptr;
+    default:
+      break;
+  }
+
+  // If it already exists, we must have processed it once, so return it now.
+  auto idx = static_cast<size_t>(id);
+  if (sDeviceFamilies[idx]) {
+    return sDeviceFamilies[idx];
+  }
+
+  sDeviceFamilies[idx] = new GfxDeviceFamily;
+  GfxDeviceFamily* deviceFamily = sDeviceFamilies[idx];
+
+  switch (id) {
+    case DeviceFamily::IntelGMA500:
+      APPEND_DEVICE(0x8108); /* IntelGMA500_1 */
+      APPEND_DEVICE(0x8109); /* IntelGMA500_2 */
+      break;
+    case DeviceFamily::IntelGMA900:
+      APPEND_DEVICE(0x2582); /* IntelGMA900_1 */
+      APPEND_DEVICE(0x2782); /* IntelGMA900_2 */
+      APPEND_DEVICE(0x2592); /* IntelGMA900_3 */
+      APPEND_DEVICE(0x2792); /* IntelGMA900_4 */
+      break;
+    case DeviceFamily::IntelGMA950:
+      APPEND_DEVICE(0x2772); /* Intel945G_1 */
+      APPEND_DEVICE(0x2776); /* Intel945G_2 */
+      APPEND_DEVICE(0x27a2); /* Intel945_1 */
+      APPEND_DEVICE(0x27a6); /* Intel945_2 */
+      APPEND_DEVICE(0x27ae); /* Intel945_3 */
+      break;
+    case DeviceFamily::IntelGMA3150:
+      APPEND_DEVICE(0xa001); /* IntelGMA3150_Nettop_1 */
+      APPEND_DEVICE(0xa002); /* IntelGMA3150_Nettop_2 */
+      APPEND_DEVICE(0xa011); /* IntelGMA3150_Netbook_1 */
+      APPEND_DEVICE(0xa012); /* IntelGMA3150_Netbook_2 */
+      break;
+    case DeviceFamily::IntelGMAX3000:
+      APPEND_DEVICE(0x2972); /* Intel946GZ_1 */
+      APPEND_DEVICE(0x2973); /* Intel946GZ_2 */
+      APPEND_DEVICE(0x2982); /* IntelG35_1 */
+      APPEND_DEVICE(0x2983); /* IntelG35_2 */
+      APPEND_DEVICE(0x2992); /* IntelQ965_1 */
+      APPEND_DEVICE(0x2993); /* IntelQ965_2 */
+      APPEND_DEVICE(0x29a2); /* IntelG965_1 */
+      APPEND_DEVICE(0x29a3); /* IntelG965_2 */
+      APPEND_DEVICE(0x29b2); /* IntelQ35_1 */
+      APPEND_DEVICE(0x29b3); /* IntelQ35_2 */
+      APPEND_DEVICE(0x29c2); /* IntelG33_1 */
+      APPEND_DEVICE(0x29c3); /* IntelG33_2 */
+      APPEND_DEVICE(0x29d2); /* IntelQ33_1 */
+      APPEND_DEVICE(0x29d3); /* IntelQ33_2 */
+      APPEND_DEVICE(0x2a02); /* IntelGL960_1 */
+      APPEND_DEVICE(0x2a03); /* IntelGL960_2 */
+      APPEND_DEVICE(0x2a12); /* IntelGM965_1 */
+      APPEND_DEVICE(0x2a13); /* IntelGM965_2 */
+      break;
+    case DeviceFamily::IntelGMAX4500HD:
+      APPEND_DEVICE(0x2a42); /* IntelGMA4500MHD_1 */
+      APPEND_DEVICE(0x2a43); /* IntelGMA4500MHD_2 */
+      APPEND_DEVICE(0x2e42); /* IntelB43_1 */
+      APPEND_DEVICE(0x2e43); /* IntelB43_2 */
+      APPEND_DEVICE(0x2e92); /* IntelB43_3 */
+      APPEND_DEVICE(0x2e93); /* IntelB43_4 */
+      APPEND_DEVICE(0x2e32); /* IntelG41_1 */
+      APPEND_DEVICE(0x2e33); /* IntelG41_2 */
+      APPEND_DEVICE(0x2e22); /* IntelG45_1 */
+      APPEND_DEVICE(0x2e23); /* IntelG45_2 */
+      APPEND_DEVICE(0x2e12); /* IntelQ45_1 */
+      APPEND_DEVICE(0x2e13); /* IntelQ45_2 */
+      break;
+    case DeviceFamily::IntelHDGraphicsToIvyBridge:
+      APPEND_DEVICE(0x015A); /* IntelIvyBridge_GT1_1 (HD Graphics) */
+      // clang-format off
+      APPEND_DEVICE(0x0152); /* IntelIvyBridge_GT1_2 (HD Graphics 2500, desktop) */
+      APPEND_DEVICE(0x0162); /* IntelIvyBridge_GT2_1 (HD Graphics 4000, desktop) */
+      APPEND_DEVICE(0x0166); /* IntelIvyBridge_GT2_2 (HD Graphics 4000, mobile) */
+      APPEND_DEVICE(0x016A); /* IntelIvyBridge_GT2_3 (HD Graphics P4000, workstation) */
+      // clang-format on
+      [[fallthrough]];
+    case DeviceFamily::IntelHDGraphicsToSandyBridge:
+      APPEND_DEVICE(0x0042); /* IntelHDGraphics */
+      APPEND_DEVICE(0x0046); /* IntelMobileHDGraphics */
+      APPEND_DEVICE(0x0102); /* IntelSandyBridge_1 */
+      APPEND_DEVICE(0x0106); /* IntelSandyBridge_2 */
+      APPEND_DEVICE(0x0112); /* IntelSandyBridge_3 */
+      APPEND_DEVICE(0x0116); /* IntelSandyBridge_4 */
+      APPEND_DEVICE(0x0122); /* IntelSandyBridge_5 */
+      APPEND_DEVICE(0x0126); /* IntelSandyBridge_6 */
+      APPEND_DEVICE(0x010a); /* IntelSandyBridge_7 */
+      break;
+    case DeviceFamily::IntelHaswell:
+      APPEND_DEVICE(0x0402); /* IntelHaswell_GT1_1 */
+      APPEND_DEVICE(0x0406); /* IntelHaswell_GT1_2 */
+      APPEND_DEVICE(0x040A); /* IntelHaswell_GT1_3 */
+      APPEND_DEVICE(0x040B); /* IntelHaswell_GT1_4 */
+      APPEND_DEVICE(0x040E); /* IntelHaswell_GT1_5 */
+      APPEND_DEVICE(0x0A02); /* IntelHaswell_GT1_6 */
+      APPEND_DEVICE(0x0A06); /* IntelHaswell_GT1_7 */
+      APPEND_DEVICE(0x0A0A); /* IntelHaswell_GT1_8 */
+      APPEND_DEVICE(0x0A0B); /* IntelHaswell_GT1_9 */
+      APPEND_DEVICE(0x0A0E); /* IntelHaswell_GT1_10 */
+      APPEND_DEVICE(0x0412); /* IntelHaswell_GT2_1 */
+      APPEND_DEVICE(0x0416); /* IntelHaswell_GT2_2 */
+      APPEND_DEVICE(0x041A); /* IntelHaswell_GT2_3 */
+      APPEND_DEVICE(0x041B); /* IntelHaswell_GT2_4 */
+      APPEND_DEVICE(0x041E); /* IntelHaswell_GT2_5 */
+      APPEND_DEVICE(0x0A12); /* IntelHaswell_GT2_6 */
+      APPEND_DEVICE(0x0A16); /* IntelHaswell_GT2_7 */
+      APPEND_DEVICE(0x0A1A); /* IntelHaswell_GT2_8 */
+      APPEND_DEVICE(0x0A1B); /* IntelHaswell_GT2_9 */
+      APPEND_DEVICE(0x0A1E); /* IntelHaswell_GT2_10 */
+      APPEND_DEVICE(0x0422); /* IntelHaswell_GT3_1 */
+      APPEND_DEVICE(0x0426); /* IntelHaswell_GT3_2 */
+      APPEND_DEVICE(0x042A); /* IntelHaswell_GT3_3 */
+      APPEND_DEVICE(0x042B); /* IntelHaswell_GT3_4 */
+      APPEND_DEVICE(0x042E); /* IntelHaswell_GT3_5 */
+      APPEND_DEVICE(0x0A22); /* IntelHaswell_GT3_6 */
+      APPEND_DEVICE(0x0A26); /* IntelHaswell_GT3_7 */
+      APPEND_DEVICE(0x0A2A); /* IntelHaswell_GT3_8 */
+      APPEND_DEVICE(0x0A2B); /* IntelHaswell_GT3_9 */
+      APPEND_DEVICE(0x0A2E); /* IntelHaswell_GT3_10 */
+      APPEND_DEVICE(0x0D22); /* IntelHaswell_GT3e_1 */
+      APPEND_DEVICE(0x0D26); /* IntelHaswell_GT3e_2 */
+      APPEND_DEVICE(0x0D2A); /* IntelHaswell_GT3e_3 */
+      APPEND_DEVICE(0x0D2B); /* IntelHaswell_GT3e_4 */
+      APPEND_DEVICE(0x0D2E); /* IntelHaswell_GT3e_5 */
+      break;
+    case DeviceFamily::IntelSandyBridge:
+      APPEND_DEVICE(0x0102);
+      APPEND_DEVICE(0x0106);
+      APPEND_DEVICE(0x010a);
+      APPEND_DEVICE(0x0112);
+      APPEND_DEVICE(0x0116);
+      APPEND_DEVICE(0x0122);
+      APPEND_DEVICE(0x0126);
+      break;
+    case DeviceFamily::IntelGen7Baytrail:
+      APPEND_DEVICE(0x0f30);
+      APPEND_DEVICE(0x0f31);
+      APPEND_DEVICE(0x0f33);
+      APPEND_DEVICE(0x0155);
+      APPEND_DEVICE(0x0157);
+      break;
+    case DeviceFamily::IntelSkylake:
+      APPEND_DEVICE(0x1902);
+      APPEND_DEVICE(0x1906);
+      APPEND_DEVICE(0x190a);
+      APPEND_DEVICE(0x190B);
+      APPEND_DEVICE(0x190e);
+      APPEND_DEVICE(0x1912);
+      APPEND_DEVICE(0x1913);
+      APPEND_DEVICE(0x1915);
+      APPEND_DEVICE(0x1916);
+      APPEND_DEVICE(0x1917);
+      APPEND_DEVICE(0x191a);
+      APPEND_DEVICE(0x191b);
+      APPEND_DEVICE(0x191d);
+      APPEND_DEVICE(0x191e);
+      APPEND_DEVICE(0x1921);
+      APPEND_DEVICE(0x1923);
+      APPEND_DEVICE(0x1926);
+      APPEND_DEVICE(0x1927);
+      APPEND_DEVICE(0x192a);
+      APPEND_DEVICE(0x192b);
+      APPEND_DEVICE(0x192d);
+      APPEND_DEVICE(0x1932);
+      APPEND_DEVICE(0x193a);
+      APPEND_DEVICE(0x193b);
+      APPEND_DEVICE(0x193d);
+      break;
+    case DeviceFamily::IntelKabyLake:
+      APPEND_DEVICE(0x5902);
+      APPEND_DEVICE(0x5906);
+      APPEND_DEVICE(0x5908);
+      APPEND_DEVICE(0x590A);
+      APPEND_DEVICE(0x590B);
+      APPEND_DEVICE(0x590E);
+      APPEND_DEVICE(0x5913);
+      APPEND_DEVICE(0x5915);
+      APPEND_DEVICE(0x5912);
+      APPEND_DEVICE(0x5916);
+      APPEND_DEVICE(0x5917);
+      APPEND_DEVICE(0x591A);
+      APPEND_DEVICE(0x591B);
+      APPEND_DEVICE(0x591D);
+      APPEND_DEVICE(0x591E);
+      APPEND_DEVICE(0x5921);
+      APPEND_DEVICE(0x5923);
+      APPEND_DEVICE(0x5926);
+      APPEND_DEVICE(0x5927);
+      APPEND_DEVICE(0x593B);
+      APPEND_DEVICE(0x591C);
+      APPEND_DEVICE(0x87C0);
+      break;
+    case DeviceFamily::IntelHD520:
+      APPEND_DEVICE(0x1916);
+      break;
+    case DeviceFamily::IntelMobileHDGraphics:
+      APPEND_DEVICE(0x0046); /* IntelMobileHDGraphics */
+      break;
+    case DeviceFamily::NvidiaBlockD3D9Layers:
+      // Glitches whilst scrolling (see bugs 612007, 644787, 645872)
+      APPEND_DEVICE(0x00f3); /* NV43 [GeForce 6200 (TM)] */
+      APPEND_DEVICE(0x0146); /* NV43 [Geforce Go 6600TE/6200TE (TM)] */
+      APPEND_DEVICE(0x014f); /* NV43 [GeForce 6200 (TM)] */
+      APPEND_DEVICE(0x0161); /* NV44 [GeForce 6200 TurboCache (TM)] */
+      APPEND_DEVICE(0x0162); /* NV44 [GeForce 6200SE TurboCache (TM)] */
+      APPEND_DEVICE(0x0163); /* NV44 [GeForce 6200 LE (TM)] */
+      APPEND_DEVICE(0x0164); /* NV44 [GeForce Go 6200 (TM)] */
+      APPEND_DEVICE(0x0167); /* NV43 [GeForce Go 6200/6400 (TM)] */
+      APPEND_DEVICE(0x0168); /* NV43 [GeForce Go 6200/6400 (TM)] */
+      APPEND_DEVICE(0x0169); /* NV44 [GeForce 6250 (TM)] */
+      APPEND_DEVICE(0x0222); /* NV44 [GeForce 6200 A-LE (TM)] */
+      APPEND_DEVICE(0x0240); /* C51PV [GeForce 6150 (TM)] */
+      APPEND_DEVICE(0x0241); /* C51 [GeForce 6150 LE (TM)] */
+      APPEND_DEVICE(0x0244); /* C51 [Geforce Go 6150 (TM)] */
+      APPEND_DEVICE(0x0245); /* C51 [Quadro NVS 210S/GeForce 6150LE (TM)] */
+      APPEND_DEVICE(0x0247); /* C51 [GeForce Go 6100 (TM)] */
+      APPEND_DEVICE(0x03d0); /* C61 [GeForce 6150SE nForce 430 (TM)] */
+      APPEND_DEVICE(0x03d1); /* C61 [GeForce 6100 nForce 405 (TM)] */
+      APPEND_DEVICE(0x03d2); /* C61 [GeForce 6100 nForce 400 (TM)] */
+      APPEND_DEVICE(0x03d5); /* C61 [GeForce 6100 nForce 420 (TM)] */
+      break;
+    case DeviceFamily::RadeonX1000:
+      // This list is from the ATIRadeonX1000.kext Info.plist
+      APPEND_DEVICE(0x7187);
+      APPEND_DEVICE(0x7210);
+      APPEND_DEVICE(0x71de);
+      APPEND_DEVICE(0x7146);
+      APPEND_DEVICE(0x7142);
+      APPEND_DEVICE(0x7109);
+      APPEND_DEVICE(0x71c5);
+      APPEND_DEVICE(0x71c0);
+      APPEND_DEVICE(0x7240);
+      APPEND_DEVICE(0x7249);
+      APPEND_DEVICE(0x7291);
+      break;
+    case DeviceFamily::RadeonCaicos:
+      APPEND_DEVICE(0x6766);
+      APPEND_DEVICE(0x6767);
+      APPEND_DEVICE(0x6768);
+      APPEND_DEVICE(0x6770);
+      APPEND_DEVICE(0x6771);
+      APPEND_DEVICE(0x6772);
+      APPEND_DEVICE(0x6778);
+      APPEND_DEVICE(0x6779);
+      APPEND_DEVICE(0x677b);
+      break;
+    case DeviceFamily::RadeonBlockZeroVideoCopy:
+      // Stoney
+      APPEND_DEVICE(0x98e4);
+      // Carrizo
+      APPEND_RANGE(0x9870, 0x9877);
+      break;
+    case DeviceFamily::Geforce7300GT:
+      APPEND_DEVICE(0x0393);
+      break;
+    case DeviceFamily::Nvidia310M:
+      APPEND_DEVICE(0x0A70);
+      break;
+    case DeviceFamily::Nvidia8800GTS:
+      APPEND_DEVICE(0x0193);
+      break;
+    case DeviceFamily::Bug1137716:
+      APPEND_DEVICE(0x0a29);
+      APPEND_DEVICE(0x0a2b);
+      APPEND_DEVICE(0x0a2d);
+      APPEND_DEVICE(0x0a35);
+      APPEND_DEVICE(0x0a6c);
+      APPEND_DEVICE(0x0a70);
+      APPEND_DEVICE(0x0a72);
+      APPEND_DEVICE(0x0a7a);
+      APPEND_DEVICE(0x0caf);
+      APPEND_DEVICE(0x0dd2);
+      APPEND_DEVICE(0x0dd3);
+      // GF180M ids
+      APPEND_DEVICE(0x0de3);
+      APPEND_DEVICE(0x0de8);
+      APPEND_DEVICE(0x0de9);
+      APPEND_DEVICE(0x0dea);
+      APPEND_DEVICE(0x0deb);
+      APPEND_DEVICE(0x0dec);
+      APPEND_DEVICE(0x0ded);
+      APPEND_DEVICE(0x0dee);
+      APPEND_DEVICE(0x0def);
+      APPEND_DEVICE(0x0df0);
+      APPEND_DEVICE(0x0df1);
+      APPEND_DEVICE(0x0df2);
+      APPEND_DEVICE(0x0df3);
+      APPEND_DEVICE(0x0df4);
+      APPEND_DEVICE(0x0df5);
+      APPEND_DEVICE(0x0df6);
+      APPEND_DEVICE(0x0df7);
+      APPEND_DEVICE(0x1050);
+      APPEND_DEVICE(0x1051);
+      APPEND_DEVICE(0x1052);
+      APPEND_DEVICE(0x1054);
+      APPEND_DEVICE(0x1055);
+      break;
+    case DeviceFamily::Bug1116812:
+      APPEND_DEVICE(0x2e32);
+      APPEND_DEVICE(0x2a02);
+      break;
+    case DeviceFamily::Bug1155608:
+      APPEND_DEVICE(0x2e22); /* IntelG45_1 */
+      break;
+    case DeviceFamily::Bug1447141:
+      APPEND_DEVICE(0x9991);
+      APPEND_DEVICE(0x9993);
+      APPEND_DEVICE(0x9996);
+      APPEND_DEVICE(0x9998);
+      APPEND_DEVICE(0x9901);
+      APPEND_DEVICE(0x990b);
+      break;
+    case DeviceFamily::Bug1207665:
+      APPEND_DEVICE(0xa001); /* Intel Media Accelerator 3150 */
+      APPEND_DEVICE(0xa002);
+      APPEND_DEVICE(0xa011);
+      APPEND_DEVICE(0xa012);
+      break;
+    case DeviceFamily::AmdR600:
+      // AMD R600 generation GPUs
+      // R600
+      APPEND_RANGE(0x9400, 0x9403);
+      APPEND_DEVICE(0x9405);
+      APPEND_RANGE(0x940a, 0x940b);
+      APPEND_DEVICE(0x940f);
+      // RV610
+      APPEND_RANGE(0x94c0, 0x94c1);
+      APPEND_RANGE(0x94c3, 0x94c9);
+      APPEND_RANGE(0x94cb, 0x94cd);
+      // RV630
+      APPEND_RANGE(0x9580, 0x9581);
+      APPEND_DEVICE(0x9583);
+      APPEND_RANGE(0x9586, 0x958f);
+      // RV670
+      APPEND_RANGE(0x9500, 0x9501);
+      APPEND_RANGE(0x9504, 0x9509);
+      APPEND_DEVICE(0x950f);
+      APPEND_DEVICE(0x9511);
+      APPEND_DEVICE(0x9515);
+      APPEND_DEVICE(0x9517);
+      APPEND_DEVICE(0x9519);
+      // RV620
+      APPEND_DEVICE(0x95c0);
+      APPEND_DEVICE(0x95c2);
+      APPEND_RANGE(0x95c4, 0x95c7);
+      APPEND_DEVICE(0x95c9);
+      APPEND_RANGE(0x95cc, 0x95cf);
+      // RV635
+      APPEND_RANGE(0x9590, 0x9591);
+      APPEND_DEVICE(0x9593);
+      APPEND_RANGE(0x9595, 0x9599);
+      APPEND_DEVICE(0x959b);
+      // RS780
+      APPEND_RANGE(0x9610, 0x9616);
+      // RS880
+      APPEND_RANGE(0x9710, 0x9715);
+      break;
+    case DeviceFamily::NvidiaWebRenderBlocked:
+      APPEND_RANGE(0x0190, 0x019e);  // early tesla
+      APPEND_RANGE(0x0500, 0x05df);  // C67-C68
+      break;
+    case DeviceFamily::IntelWebRenderBlocked:
+      // powervr
+      // sgx535
+      APPEND_DEVICE(0x2e5b);
+      APPEND_DEVICE(0x8108);
+      APPEND_DEVICE(0x8109);
+      APPEND_DEVICE(0x4102);
+      // sgx545
+      APPEND_DEVICE(0x0be0);
+      APPEND_DEVICE(0x0be1);
+      APPEND_DEVICE(0x0be3);
+      APPEND_RANGE(0x08c7, 0x08cf);
+
+      // gen4
+      APPEND_DEVICE(0x2972);
+      APPEND_DEVICE(0x2973);
+      APPEND_DEVICE(0x2992);
+      APPEND_DEVICE(0x2993);
+      APPEND_DEVICE(0x29a2);
+      APPEND_DEVICE(0x29a3);
+
+      APPEND_DEVICE(0x2982);
+      APPEND_DEVICE(0x2983);
+
+      APPEND_DEVICE(0x2a02);
+      APPEND_DEVICE(0x2a03);
+      APPEND_DEVICE(0x2a12);
+      APPEND_DEVICE(0x2a13);
+
+      // gen4.5
+      APPEND_DEVICE(0x2e02);
+      APPEND_DEVICE(0x2e42); /* IntelB43_1 */
+      APPEND_DEVICE(0x2e43); /* IntelB43_2 */
+      APPEND_DEVICE(0x2e92); /* IntelB43_3 */
+      APPEND_DEVICE(0x2e93); /* IntelB43_4 */
+      APPEND_DEVICE(0x2e12); /* IntelQ45_1 */
+      APPEND_DEVICE(0x2e13); /* IntelQ45_2 */
+      APPEND_DEVICE(0x2e32); /* IntelG41_1 */
+      APPEND_DEVICE(0x2e33); /* IntelG41_2 */
+      APPEND_DEVICE(0x2e22); /* IntelG45_1 */
+
+      APPEND_DEVICE(0x2e23); /* IntelG45_2 */
+      APPEND_DEVICE(0x2a42); /* IntelGMA4500MHD_1 */
+      APPEND_DEVICE(0x2a43); /* IntelGMA4500MHD_2 */
+
+      // gen5 (ironlake)
+      APPEND_DEVICE(0x0042);
+      APPEND_DEVICE(0x0046);
+      break;
+    // This should never happen, but we get a warning if we don't handle this.
+    case DeviceFamily::Max:
+    case DeviceFamily::All:
+    case DeviceFamily::IntelAll:
+    case DeviceFamily::NvidiaAll:
+    case DeviceFamily::AtiAll:
+    case DeviceFamily::MicrosoftAll:
+    case DeviceFamily::ParallelsAll:
+    case DeviceFamily::QualcommAll:
+    case DeviceFamily::AppleAll:
+    case DeviceFamily::AmazonAll:
+      NS_WARNING("Invalid DeviceFamily id");
+      break;
+  }
+
+  return deviceFamily;
+}
+
+// Macro for assigning a window protocol id to a string.
+#define DECLARE_WINDOW_PROTOCOL_ID(name, windowProtocolId) \
+  case WindowProtocol::name:                               \
+    sWindowProtocol[idx]->AssignLiteral(windowProtocolId); \
+    break;
+
+const nsAString& GfxDriverInfo::GetWindowProtocol(WindowProtocol id) {
+  if (id >= WindowProtocol::Max) {
+    MOZ_ASSERT_UNREACHABLE("WindowProtocol id is out of range");
+    id = WindowProtocol::All;
+  }
+
+  auto idx = static_cast<size_t>(id);
+  if (sWindowProtocol[idx]) {
+    return *sWindowProtocol[idx];
+  }
+
+  sWindowProtocol[idx] = new nsString();
+
+  switch (id) {
+    DECLARE_WINDOW_PROTOCOL_ID(X11, "x11");
+    DECLARE_WINDOW_PROTOCOL_ID(XWayland, "xwayland");
+    DECLARE_WINDOW_PROTOCOL_ID(Wayland, "wayland");
+    DECLARE_WINDOW_PROTOCOL_ID(WaylandDRM, "wayland/drm");
+    DECLARE_WINDOW_PROTOCOL_ID(WaylandAll, "wayland/all");
+    DECLARE_WINDOW_PROTOCOL_ID(X11All, "x11/all");
+    case WindowProtocol::Max:  // Suppress a warning.
+      DECLARE_WINDOW_PROTOCOL_ID(All, "");
+  }
+
+  return *sWindowProtocol[idx];
+}
+
+// Macro for assigning a device vendor id to a string.
+#define DECLARE_VENDOR_ID(name, deviceId)         \
+  case DeviceVendor::name:                        \
+    sDeviceVendors[idx]->AssignLiteral(deviceId); \
+    break;
+
+const nsAString& GfxDriverInfo::GetDeviceVendor(DeviceFamily id) {
+  if (id >= DeviceFamily::Max) {
+    MOZ_ASSERT_UNREACHABLE("DeviceVendor id is out of range");
+    id = DeviceFamily::All;
+  }
+
+  DeviceVendor vendor = DeviceVendor::All;
+  switch (id) {
+    case DeviceFamily::IntelAll:
+    case DeviceFamily::IntelGMA500:
+    case DeviceFamily::IntelGMA900:
+    case DeviceFamily::IntelGMA950:
+    case DeviceFamily::IntelGMA3150:
+    case DeviceFamily::IntelGMAX3000:
+    case DeviceFamily::IntelGMAX4500HD:
+    case DeviceFamily::IntelHDGraphicsToIvyBridge:
+    case DeviceFamily::IntelHDGraphicsToSandyBridge:
+    case DeviceFamily::IntelHaswell:
+    case DeviceFamily::IntelSandyBridge:
+    case DeviceFamily::IntelGen7Baytrail:
+    case DeviceFamily::IntelSkylake:
+    case DeviceFamily::IntelKabyLake:
+    case DeviceFamily::IntelHD520:
+    case DeviceFamily::IntelMobileHDGraphics:
+    case DeviceFamily::IntelWebRenderBlocked:
+    case DeviceFamily::Bug1116812:
+    case DeviceFamily::Bug1155608:
+    case DeviceFamily::Bug1207665:
+      vendor = DeviceVendor::Intel;
+      break;
+    case DeviceFamily::NvidiaAll:
+    case DeviceFamily::NvidiaBlockD3D9Layers:
+    case DeviceFamily::NvidiaWebRenderBlocked:
+    case DeviceFamily::Geforce7300GT:
+    case DeviceFamily::Nvidia310M:
+    case DeviceFamily::Nvidia8800GTS:
+    case DeviceFamily::Bug1137716:
+      vendor = DeviceVendor::NVIDIA;
+      break;
+    case DeviceFamily::AtiAll:
+    case DeviceFamily::RadeonBlockZeroVideoCopy:
+    case DeviceFamily::RadeonCaicos:
+    case DeviceFamily::RadeonX1000:
+    case DeviceFamily::Bug1447141:
+    case DeviceFamily::AmdR600:
+      vendor = DeviceVendor::ATI;
+      break;
+    case DeviceFamily::MicrosoftAll:
+      vendor = DeviceVendor::Microsoft;
+      break;
+    case DeviceFamily::ParallelsAll:
+      vendor = DeviceVendor::Parallels;
+      break;
+    case DeviceFamily::AppleAll:
+      vendor = DeviceVendor::Apple;
+      break;
+    case DeviceFamily::AmazonAll:
+      vendor = DeviceVendor::Amazon;
+      break;
+    case DeviceFamily::QualcommAll:
+      // Choose an arbitrary Qualcomm PCI VENdor ID for now.
+      // TODO: This should be "QCOM" when Windows device ID parsing is reworked.
+      vendor = DeviceVendor::Qualcomm;
+      break;
+    case DeviceFamily::All:
+    case DeviceFamily::Max:
+      break;
+  }
+
+  return GetDeviceVendor(vendor);
+}
+
+const nsAString& GfxDriverInfo::GetDeviceVendor(DeviceVendor id) {
+  if (id >= DeviceVendor::Max) {
+    MOZ_ASSERT_UNREACHABLE("DeviceVendor id is out of range");
+    id = DeviceVendor::All;
+  }
+
+  auto idx = static_cast<size_t>(id);
+  if (sDeviceVendors[idx]) {
+    return *sDeviceVendors[idx];
+  }
+
+  sDeviceVendors[idx] = new nsString();
+
+  switch (id) {
+    DECLARE_VENDOR_ID(Intel, "0x8086");
+    DECLARE_VENDOR_ID(NVIDIA, "0x10de");
+    DECLARE_VENDOR_ID(ATI, "0x1002");
+    // AMD has 0x1022 but continues to release GPU hardware under ATI.
+    DECLARE_VENDOR_ID(Microsoft, "0x1414");
+    DECLARE_VENDOR_ID(MicrosoftBasic, "0x00ba");
+    DECLARE_VENDOR_ID(MicrosoftHyperV, "0x000b");
+    DECLARE_VENDOR_ID(Parallels, "0x1ab8");
+    DECLARE_VENDOR_ID(VMWare, "0x15ad");
+    DECLARE_VENDOR_ID(VirtualBox, "0x80ee");
+    DECLARE_VENDOR_ID(Apple, "0x106b");
+    DECLARE_VENDOR_ID(Amazon, "0x1d0f");
+    // Choose an arbitrary Qualcomm PCI VENdor ID for now.
+    // TODO: This should be "QCOM" when Windows device ID parsing is reworked.
+    DECLARE_VENDOR_ID(Qualcomm, "0x5143");
+    case DeviceVendor::Max:  // Suppress a warning.
+      DECLARE_VENDOR_ID(All, "");
+  }
+
+  return *sDeviceVendors[idx];
+}
+
+// Macro for assigning a driver vendor id to a string.
+#define DECLARE_DRIVER_VENDOR_ID(name, driverVendorId)  \
+  case DriverVendor::name:                              \
+    sDriverVendors[idx]->AssignLiteral(driverVendorId); \
+    break;
+
+const nsAString& GfxDriverInfo::GetDriverVendor(DriverVendor id) {
+  if (id >= DriverVendor::Max) {
+    MOZ_ASSERT_UNREACHABLE("DriverVendor id is out of range");
+    id = DriverVendor::All;
+  }
+
+  auto idx = static_cast<size_t>(id);
+  if (sDriverVendors[idx]) {
+    return *sDriverVendors[idx];
+  }
+
+  sDriverVendors[idx] = new nsString();
+
+  switch (id) {
+    DECLARE_DRIVER_VENDOR_ID(MesaAll, "mesa/all");
+    DECLARE_DRIVER_VENDOR_ID(MesaLLVMPipe, "mesa/llvmpipe");
+    DECLARE_DRIVER_VENDOR_ID(MesaSoftPipe, "mesa/softpipe");
+    DECLARE_DRIVER_VENDOR_ID(MesaSWRast, "mesa/swrast");
+    DECLARE_DRIVER_VENDOR_ID(MesaSWUnknown, "mesa/software-unknown");
+    DECLARE_DRIVER_VENDOR_ID(MesaUnknown, "mesa/unknown");
+    DECLARE_DRIVER_VENDOR_ID(MesaR600, "mesa/r600");
+    DECLARE_DRIVER_VENDOR_ID(MesaNouveau, "mesa/nouveau");
+    DECLARE_DRIVER_VENDOR_ID(NonMesaAll, "non-mesa/all");
+    DECLARE_DRIVER_VENDOR_ID(HardwareMesaAll, "mesa/hw-all");
+    DECLARE_DRIVER_VENDOR_ID(SoftwareMesaAll, "mesa/sw-all");
+    DECLARE_DRIVER_VENDOR_ID(MesaNonIntelNvidiaAtiAll,
+                             "mesa/non-intel-nvidia-ati-all");
+    DECLARE_DRIVER_VENDOR_ID(MesaVM, "mesa/vmwgfx");
+    case DriverVendor::Max:  // Suppress a warning.
+      DECLARE_DRIVER_VENDOR_ID(All, "");
+  }
+
+  return *sDriverVendors[idx];
+}
diff --git a/widget/GfxDriverInfo.h b/widget/GfxDriverInfo.h
new file mode 100644
index 0000000000..a584c7ac3f
--- /dev/null
+++ b/widget/GfxDriverInfo.h
@@ -0,0 +1,501 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_GfxDriverInfo_h__
+#define __mozilla_widget_GfxDriverInfo_h__
+
+#include "nsString.h"
+#include "nsTArray.h"
+
+// Macros for adding a blocklist item to the static list. _EXT variants
+// allow one to specify all available parameters, including those available
+// only on specific platforms (e.g. desktop environment and driver vendor
+// for Linux.)
+
+#define APPEND_TO_DRIVER_BLOCKLIST_EXT(                                       \
+    os, screen, battery, windowProtocol, driverVendor, devices, feature,      \
+    featureStatus, driverComparator, driverVersion, ruleId, suggestedVersion) \
+  sDriverInfo->AppendElement(GfxDriverInfo(                                   \
+      os, screen, battery,                                                    \
+      (nsAString&)GfxDriverInfo::GetWindowProtocol(windowProtocol),           \
+      (nsAString&)GfxDriverInfo::GetDeviceVendor(devices),                    \
+      (nsAString&)GfxDriverInfo::GetDriverVendor(driverVendor),               \
+      (GfxDeviceFamily*)GfxDriverInfo::GetDeviceFamily(devices), feature,     \
+      featureStatus, driverComparator, driverVersion, ruleId,                 \
+      suggestedVersion))
+
+#define APPEND_TO_DRIVER_BLOCKLIST(os, devices, feature, featureStatus,     \
+                                   driverComparator, driverVersion, ruleId, \
+                                   suggestedVersion)                        \
+  APPEND_TO_DRIVER_BLOCKLIST_EXT(                                           \
+      os, ScreenSizeStatus::All, BatteryStatus::All, WindowProtocol::All,   \
+      DriverVendor::All, devices, feature, featureStatus, driverComparator, \
+      driverVersion, ruleId, suggestedVersion)
+
+#define APPEND_TO_DRIVER_BLOCKLIST2_EXT(                                  \
+    os, screen, battery, windowProtocol, driverVendor, devices, feature,  \
+    featureStatus, driverComparator, driverVersion, ruleId)               \
+  sDriverInfo->AppendElement(GfxDriverInfo(                               \
+      os, screen, battery,                                                \
+      (nsAString&)GfxDriverInfo::GetWindowProtocol(windowProtocol),       \
+      (nsAString&)GfxDriverInfo::GetDeviceVendor(devices),                \
+      (nsAString&)GfxDriverInfo::GetDriverVendor(driverVendor),           \
+      (GfxDeviceFamily*)GfxDriverInfo::GetDeviceFamily(devices), feature, \
+      featureStatus, driverComparator, driverVersion, ruleId))
+
+#define APPEND_TO_DRIVER_BLOCKLIST2(os, devices, feature, featureStatus,     \
+                                    driverComparator, driverVersion, ruleId) \
+  APPEND_TO_DRIVER_BLOCKLIST2_EXT(                                           \
+      os, ScreenSizeStatus::All, BatteryStatus::All, WindowProtocol::All,    \
+      DriverVendor::All, devices, feature, featureStatus, driverComparator,  \
+      driverVersion, ruleId)
+
+#define APPEND_TO_DRIVER_BLOCKLIST_RANGE_EXT(                                 \
+    os, screen, battery, windowProtocol, driverVendor, devices, feature,      \
+    featureStatus, driverComparator, driverVersion, driverVersionMax, ruleId, \
+    suggestedVersion)                                                         \
+  do {                                                                        \
+    MOZ_ASSERT((driverComparator) == DRIVER_BETWEEN_EXCLUSIVE ||              \
+               (driverComparator) == DRIVER_BETWEEN_INCLUSIVE ||              \
+               (driverComparator) == DRIVER_BETWEEN_INCLUSIVE_START);         \
+    GfxDriverInfo info(                                                       \
+        os, screen, battery,                                                  \
+        (nsAString&)GfxDriverInfo::GetWindowProtocol(windowProtocol),         \
+        (nsAString&)GfxDriverInfo::GetDeviceVendor(devices),                  \
+        (nsAString&)GfxDriverInfo::GetDriverVendor(driverVendor),             \
+        (GfxDeviceFamily*)GfxDriverInfo::GetDeviceFamily(devices), feature,   \
+        featureStatus, driverComparator, driverVersion, ruleId,               \
+        suggestedVersion);                                                    \
+    info.mDriverVersionMax = driverVersionMax;                                \
+    sDriverInfo->AppendElement(info);                                         \
+  } while (false)
+
+#define APPEND_TO_DRIVER_BLOCKLIST_RANGE(                                   \
+    os, devices, feature, featureStatus, driverComparator, driverVersion,   \
+    driverVersionMax, ruleId, suggestedVersion)                             \
+  APPEND_TO_DRIVER_BLOCKLIST_RANGE_EXT(                                     \
+      os, ScreenSizeStatus::All, BatteryStatus::All, WindowProtocol::All,   \
+      DriverVendor::All, devices, feature, featureStatus, driverComparator, \
+      driverVersion, driverVersionMax, ruleId, suggestedVersion)
+
+#define APPEND_TO_DRIVER_BLOCKLIST_RANGE_GPU2_EXT(                            \
+    os, screen, battery, windowProtocol, driverVendor, devices, feature,      \
+    featureStatus, driverComparator, driverVersion, driverVersionMax, ruleId, \
+    suggestedVersion)                                                         \
+  do {                                                                        \
+    MOZ_ASSERT((driverComparator) == DRIVER_BETWEEN_EXCLUSIVE ||              \
+               (driverComparator) == DRIVER_BETWEEN_INCLUSIVE ||              \
+               (driverComparator) == DRIVER_BETWEEN_INCLUSIVE_START);         \
+    GfxDriverInfo info(                                                       \
+        os, screen, battery,                                                  \
+        (nsAString&)GfxDriverInfo::GetWindowProtocol(windowProtocol),         \
+        (nsAString&)GfxDriverInfo::GetDeviceVendor(devices),                  \
+        (nsAString&)GfxDriverInfo::GetDriverVendor(driverVendor),             \
+        (GfxDeviceFamily*)GfxDriverInfo::GetDeviceFamily(devices), feature,   \
+        featureStatus, driverComparator, driverVersion, ruleId,               \
+        suggestedVersion, false, true);                                       \
+    info.mDriverVersionMax = driverVersionMax;                                \
+    sDriverInfo->AppendElement(info);                                         \
+  } while (false)
+
+#define APPEND_TO_DRIVER_BLOCKLIST_RANGE_GPU2(                              \
+    os, devices, feature, featureStatus, driverComparator, driverVersion,   \
+    driverVersionMax, ruleId, suggestedVersion)                             \
+  APPEND_TO_DRIVER_BLOCKLIST_RANGE_GPU2_EXT(                                \
+      os, ScreenSizeStatus::All, BatteryStatus::All, WindowProtocol::All,   \
+      DriverVendor::All, devices, feature, featureStatus, driverComparator, \
+      driverVersion, driverVersionMax, ruleId, suggestedVersion)
+
+namespace mozilla {
+namespace widget {
+
+enum class OperatingSystem : uint8_t {
+  Unknown,
+  Windows,
+  WindowsXP,
+  WindowsServer2003,
+  WindowsVista,
+  Windows7,
+  Windows8,
+  Windows8_1,
+  Windows10,
+  RecentWindows10,
+  NotRecentWindows10,
+  Linux,
+  OSX,
+  OSX10_5,
+  OSX10_6,
+  OSX10_7,
+  OSX10_8,
+  OSX10_9,
+  OSX10_10,
+  OSX10_11,
+  OSX10_12,
+  OSX10_13,
+  OSX10_14,
+  OSX10_15,
+  OSX11_0,
+  Android,
+  Ios
+};
+
+enum VersionComparisonOp {
+  DRIVER_LESS_THAN,                    // driver <  version
+  DRIVER_BUILD_ID_LESS_THAN,           // driver build id <  version
+  DRIVER_LESS_THAN_OR_EQUAL,           // driver <= version
+  DRIVER_BUILD_ID_LESS_THAN_OR_EQUAL,  // driver build id <= version
+  DRIVER_GREATER_THAN,                 // driver >  version
+  DRIVER_GREATER_THAN_OR_EQUAL,        // driver >= version
+  DRIVER_EQUAL,                        // driver == version
+  DRIVER_NOT_EQUAL,                    // driver != version
+  DRIVER_BETWEEN_EXCLUSIVE,        // driver > version && driver < versionMax
+  DRIVER_BETWEEN_INCLUSIVE,        // driver >= version && driver <= versionMax
+  DRIVER_BETWEEN_INCLUSIVE_START,  // driver >= version && driver < versionMax
+  DRIVER_COMPARISON_IGNORED
+};
+
+enum class DeviceFamily : uint8_t {
+  All,
+  IntelAll,
+  NvidiaAll,
+  AtiAll,
+  MicrosoftAll,
+  ParallelsAll,
+  QualcommAll,
+  AppleAll,
+  AmazonAll,
+  IntelGMA500,
+  IntelGMA900,
+  IntelGMA950,
+  IntelGMA3150,
+  IntelGMAX3000,
+  IntelGMAX4500HD,
+  IntelHDGraphicsToIvyBridge,
+  IntelHDGraphicsToSandyBridge,
+  IntelHaswell,
+  IntelSandyBridge,
+  IntelGen7Baytrail,
+  IntelSkylake,
+  IntelKabyLake,
+  IntelHD520,
+  IntelMobileHDGraphics,
+  NvidiaBlockD3D9Layers,
+  RadeonX1000,
+  RadeonCaicos,
+  RadeonBlockZeroVideoCopy,
+  Geforce7300GT,
+  Nvidia310M,
+  Nvidia8800GTS,
+  Bug1137716,
+  Bug1116812,
+  Bug1155608,
+  Bug1207665,
+  Bug1447141,
+  AmdR600,
+  IntelWebRenderBlocked,
+  NvidiaWebRenderBlocked,
+
+  Max
+};
+
+enum class DeviceVendor : uint8_t {
+  All,  // There is an assumption that this is the first enum
+  Intel,
+  NVIDIA,
+  ATI,
+  Microsoft,
+  Parallels,
+  VMWare,
+  VirtualBox,
+  Qualcomm,
+  MicrosoftBasic,
+  MicrosoftHyperV,
+  Apple,
+  Amazon,
+
+  Max
+};
+
+enum DriverVendor : uint8_t {
+  All,  // There is an assumption that this is the first enum
+  // Wildcard for all Mesa drivers.
+  MesaAll,
+  // Note that the following list of Mesa drivers is not comprehensive; we pull
+  // the DRI driver at runtime. These drivers are provided for convenience when
+  // populating the local blocklist.
+  MesaLLVMPipe,
+  MesaSoftPipe,
+  MesaSWRast,
+  MesaSWUnknown,
+  // AMD
+  MesaR600,
+  // Nouveau: Open-source nvidia
+  MesaNouveau,
+  // A generic ID to be provided when we can't determine the DRI driver on Mesa.
+  MesaUnknown,
+  // Wildcard for all non-Mesa drivers.
+  NonMesaAll,
+  // Wildcard for all hardware Mesa drivers.
+  HardwareMesaAll,
+  // Wildcard for all software Mesa drivers.
+  SoftwareMesaAll,
+  // Wildcard for all non-Intel/NVIDIA/ATI Mesa drivers.
+  MesaNonIntelNvidiaAtiAll,
+  // Running in VM.
+  MesaVM,
+
+  Max
+};
+
+enum class WindowProtocol : uint8_t {
+  All,  // There is an assumption that this is the first enum
+  X11,
+  XWayland,
+  Wayland,
+  WaylandDRM,
+  // Wildcard for all Wayland variants, excluding XWayland.
+  WaylandAll,
+  // Wildcard for all X11 variants, including XWayland.
+  X11All,
+  Max
+};
+
+enum class BatteryStatus : uint8_t { All, Present, None };
+
+enum class ScreenSizeStatus : uint8_t {
+  All,
+  Small,           // <= 1900x1200
+  SmallAndMedium,  // <= 3440x1440
+  Medium,          // <= 3440x1440 && > 1900x1200
+  MediumAndLarge,  // >1900x1200
+  Large            // > 3440x1440
+};
+
+/* Array of devices to match, or an empty array for all devices */
+class GfxDeviceFamily final {
+ public:
+  GfxDeviceFamily() = default;
+
+  void Append(const nsAString& aDeviceId);
+  void AppendRange(int32_t aBeginDeviceId, int32_t aEndDeviceId);
+
+  bool IsEmpty() const { return mIds.IsEmpty() && mRanges.IsEmpty(); }
+
+  nsresult Contains(nsAString& aDeviceId) const;
+
+ private:
+  struct DeviceRange {
+    int32_t mBegin;
+    int32_t mEnd;
+  };
+
+  CopyableTArray<nsString> mIds;
+  CopyableTArray<DeviceRange> mRanges;
+};
+
+struct GfxDriverInfo {
+  // If |ownDevices| is true, you are transferring ownership of the devices
+  // array, and it will be deleted when this GfxDriverInfo is destroyed.
+  GfxDriverInfo(OperatingSystem os, ScreenSizeStatus aScreen,
+                BatteryStatus aBattery, const nsAString& windowProtocol,
+                const nsAString& vendor, const nsAString& driverVendor,
+                GfxDeviceFamily* devices, int32_t feature,
+                int32_t featureStatus, VersionComparisonOp op,
+                uint64_t driverVersion, const char* ruleId,
+                const char* suggestedVersion = nullptr, bool ownDevices = false,
+                bool gpu2 = false);
+
+  GfxDriverInfo();
+  GfxDriverInfo(const GfxDriverInfo&);
+  ~GfxDriverInfo();
+
+  OperatingSystem mOperatingSystem;
+  uint32_t mOperatingSystemVersion;
+  ScreenSizeStatus mScreen;
+  BatteryStatus mBattery;
+  nsString mWindowProtocol;
+
+  nsString mAdapterVendor;
+  nsString mDriverVendor;
+
+  const GfxDeviceFamily* mDevices;
+
+  // Whether the mDevices array should be deleted when this structure is
+  // deallocated. False by default.
+  bool mDeleteDevices;
+
+  /* A feature from nsIGfxInfo, or a wildcard set of features */
+  int32_t mFeature;
+  /* Block all features */
+  static constexpr int32_t allFeatures = -1;
+  /* Block all features not permitted by OnlyAllowFeatureOnKnownConfig */
+  static constexpr int32_t optionalFeatures = -2;
+
+  /* A feature status from nsIGfxInfo */
+  int32_t mFeatureStatus;
+
+  VersionComparisonOp mComparisonOp;
+
+  /* versions are assumed to be A.B.C.D packed as 0xAAAABBBBCCCCDDDD */
+  uint64_t mDriverVersion;
+  uint64_t mDriverVersionMax;
+  static constexpr uint64_t allDriverVersions = ~(uint64_t(0));
+
+  const char* mSuggestedVersion;
+  nsCString mRuleId;
+
+  static const GfxDeviceFamily* GetDeviceFamily(DeviceFamily id);
+  static GfxDeviceFamily*
+      sDeviceFamilies[static_cast<size_t>(DeviceFamily::Max)];
+
+  static const nsAString& GetWindowProtocol(WindowProtocol id);
+  static nsString* sWindowProtocol[static_cast<size_t>(WindowProtocol::Max)];
+
+  static const nsAString& GetDeviceVendor(DeviceVendor id);
+  static const nsAString& GetDeviceVendor(DeviceFamily id);
+  static nsString* sDeviceVendors[static_cast<size_t>(DeviceVendor::Max)];
+
+  static const nsAString& GetDriverVendor(DriverVendor id);
+  static nsString* sDriverVendors[static_cast<size_t>(DriverVendor::Max)];
+
+  nsString mModel, mHardware, mProduct, mManufacturer;
+
+  bool mGpu2;
+};
+
+inline uint64_t DriverVersion(uint32_t a, uint32_t b, uint32_t c, uint32_t d) {
+  return (uint64_t(a) << 48) | (uint64_t(b) << 32) | (uint64_t(c) << 16) |
+         uint64_t(d);
+}
+
+inline uint64_t V(uint32_t a, uint32_t b, uint32_t c, uint32_t d) {
+#ifdef XP_WIN
+  // We make sure every driver number is padded by 0s, this will allow us the
+  // easiest 'compare as if decimals' approach. See ParseDriverVersion for a
+  // more extensive explanation of this approach.
+  while (b > 0 && b < 1000) {
+    b *= 10;
+  }
+  while (c > 0 && c < 1000) {
+    c *= 10;
+  }
+  while (d > 0 && d < 1000) {
+    d *= 10;
+  }
+#endif
+  return DriverVersion(a, b, c, d);
+}
+
+// All destination string storage needs to have at least 5 bytes available.
+inline bool SplitDriverVersion(const char* aSource, char* aAStr, char* aBStr,
+                               char* aCStr, char* aDStr) {
+  // sscanf doesn't do what we want here to we parse this manually.
+  int len = strlen(aSource);
+
+  // This "4" is hardcoded in a few places, including once as a 3.
+  char* dest[4] = {aAStr, aBStr, aCStr, aDStr};
+  unsigned destIdx = 0;
+  unsigned destPos = 0;
+
+  for (int i = 0; i < len; i++) {
+    if (destIdx >= 4) {
+      // Invalid format found. Ensure we don't access dest beyond bounds.
+      return false;
+    }
+
+    if (aSource[i] == '.') {
+      MOZ_ASSERT(destIdx < 4 && destPos <= 4);
+      dest[destIdx++][destPos] = 0;
+      destPos = 0;
+      continue;
+    }
+
+    if (destPos > 3) {
+      // Ignore more than 4 chars. Ensure we never access dest[destIdx]
+      // beyond its bounds.
+      continue;
+    }
+
+    MOZ_ASSERT(destIdx < 4 && destPos < 4);
+    dest[destIdx][destPos++] = aSource[i];
+  }
+
+  // Take care of the trailing period
+  if (destIdx >= 4) {
+    return false;
+  }
+
+  // Add last terminator.
+  MOZ_ASSERT(destIdx < 4 && destPos <= 4);
+  dest[destIdx][destPos] = 0;
+  for (int unusedDestIdx = destIdx + 1; unusedDestIdx < 4; unusedDestIdx++) {
+    dest[unusedDestIdx][0] = 0;
+  }
+
+  if (destIdx != 3) {
+    return false;
+  }
+  return true;
+}
+
+// This allows us to pad driver version 'substrings' with 0s, this
+// effectively allows us to treat the version numbers as 'decimals'. This is
+// a little strange but this method seems to do the right thing for all
+// different vendor's driver strings. i.e. .98 will become 9800, which is
+// larger than .978 which would become 9780.
+inline void PadDriverDecimal(char* aString) {
+  for (int i = 0; i < 4; i++) {
+    if (!aString[i]) {
+      for (int c = i; c < 4; c++) {
+        aString[c] = '0';
+      }
+      break;
+    }
+  }
+  aString[4] = 0;
+}
+
+inline bool ParseDriverVersion(const nsAString& aVersion,
+                               uint64_t* aNumericVersion) {
+  *aNumericVersion = 0;
+
+#ifndef ANDROID
+  int a, b, c, d;
+  char aStr[8], bStr[8], cStr[8], dStr[8];
+  /* honestly, why do I even bother */
+  if (!SplitDriverVersion(NS_LossyConvertUTF16toASCII(aVersion).get(), aStr,
+                          bStr, cStr, dStr))
+    return false;
+
+#  ifdef XP_WIN
+  PadDriverDecimal(bStr);
+  PadDriverDecimal(cStr);
+  PadDriverDecimal(dStr);
+#  endif
+
+  a = atoi(aStr);
+  b = atoi(bStr);
+  c = atoi(cStr);
+  d = atoi(dStr);
+
+  if (a < 0 || a > 0xffff) return false;
+  if (b < 0 || b > 0xffff) return false;
+  if (c < 0 || c > 0xffff) return false;
+  if (d < 0 || d > 0xffff) return false;
+
+  *aNumericVersion = DriverVersion(a, b, c, d);
+#else
+  // Can't use aVersion.ToInteger() because that's not compiled into our code
+  // unless we have XPCOM_GLUE_AVOID_NSPR disabled.
+  *aNumericVersion = atoi(NS_LossyConvertUTF16toASCII(aVersion).get());
+#endif
+  MOZ_ASSERT(*aNumericVersion != GfxDriverInfo::allDriverVersions);
+  return true;
+}
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /*__mozilla_widget_GfxDriverInfo_h__ */
diff --git a/widget/GfxInfoBase.cpp b/widget/GfxInfoBase.cpp
new file mode 100644
index 0000000000..3e32ffbe15
--- /dev/null
+++ b/widget/GfxInfoBase.cpp
@@ -0,0 +1,2219 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+
+#include "GfxInfoBase.h"
+
+#include <mutex>  // std::call_once
+
+#include "GfxDriverInfo.h"
+#include "js/Array.h"               // JS::GetArrayLength, JS::NewArrayObject
+#include "js/PropertyAndElement.h"  // JS_SetElement, JS_SetProperty
+#include "nsCOMPtr.h"
+#include "nsCOMArray.h"
+#include "nsString.h"
+#include "nsUnicharUtils.h"
+#include "nsVersionComparator.h"
+#include "mozilla/Services.h"
+#include "mozilla/Observer.h"
+#include "nsIObserver.h"
+#include "nsIObserverService.h"
+#include "nsTArray.h"
+#include "nsXULAppAPI.h"
+#include "nsIXULAppInfo.h"
+#include "mozilla/BinarySearch.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_gfx.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/BuildConstants.h"
+#include "mozilla/gfx/GPUProcessManager.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/widget/ScreenManager.h"
+#include "mozilla/widget/Screen.h"
+
+#include "jsapi.h"
+
+#include "gfxPlatform.h"
+#include "gfxConfig.h"
+#include "DriverCrashGuard.h"
+
+#ifdef MOZ_WIDGET_ANDROID
+#  include <set>
+#  include "AndroidBuild.h"
+#endif
+
+using namespace mozilla::widget;
+using namespace mozilla;
+using mozilla::MutexAutoLock;
+
+nsTArray<GfxDriverInfo>* GfxInfoBase::sDriverInfo;
+StaticAutoPtr<nsTArray<gfx::GfxInfoFeatureStatus>> GfxInfoBase::sFeatureStatus;
+bool GfxInfoBase::sDriverInfoObserverInitialized;
+bool GfxInfoBase::sShutdownOccurred;
+
+// Call this when setting sFeatureStatus to a non-null pointer to
+// ensure destruction even if the GfxInfo component is never instantiated.
+static void InitFeatureStatus(nsTArray<gfx::GfxInfoFeatureStatus>* aPtr) {
+  static std::once_flag sOnce;
+  std::call_once(sOnce, [] { ClearOnShutdown(&GfxInfoBase::sFeatureStatus); });
+  GfxInfoBase::sFeatureStatus = aPtr;
+}
+
+// Observes for shutdown so that the child GfxDriverInfo list is freed.
+class ShutdownObserver : public nsIObserver {
+  virtual ~ShutdownObserver() = default;
+
+ public:
+  ShutdownObserver() = default;
+
+  NS_DECL_ISUPPORTS
+
+  NS_IMETHOD Observe(nsISupports* subject, const char* aTopic,
+                     const char16_t* aData) override {
+    MOZ_ASSERT(strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0);
+
+    delete GfxInfoBase::sDriverInfo;
+    GfxInfoBase::sDriverInfo = nullptr;
+
+    for (auto& deviceFamily : GfxDriverInfo::sDeviceFamilies) {
+      delete deviceFamily;
+      deviceFamily = nullptr;
+    }
+
+    for (auto& windowProtocol : GfxDriverInfo::sWindowProtocol) {
+      delete windowProtocol;
+      windowProtocol = nullptr;
+    }
+
+    for (auto& deviceVendor : GfxDriverInfo::sDeviceVendors) {
+      delete deviceVendor;
+      deviceVendor = nullptr;
+    }
+
+    for (auto& driverVendor : GfxDriverInfo::sDriverVendors) {
+      delete driverVendor;
+      driverVendor = nullptr;
+    }
+
+    GfxInfoBase::sShutdownOccurred = true;
+
+    return NS_OK;
+  }
+};
+
+NS_IMPL_ISUPPORTS(ShutdownObserver, nsIObserver)
+
+static void InitGfxDriverInfoShutdownObserver() {
+  if (GfxInfoBase::sDriverInfoObserverInitialized) return;
+
+  GfxInfoBase::sDriverInfoObserverInitialized = true;
+
+  nsCOMPtr<nsIObserverService> observerService = services::GetObserverService();
+  if (!observerService) {
+    NS_WARNING("Could not get observer service!");
+    return;
+  }
+
+  ShutdownObserver* obs = new ShutdownObserver();
+  observerService->AddObserver(obs, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
+}
+
+using namespace mozilla::widget;
+using namespace mozilla::gfx;
+using namespace mozilla;
+
+NS_IMPL_ISUPPORTS(GfxInfoBase, nsIGfxInfo, nsIObserver,
+                  nsISupportsWeakReference)
+
+#define BLOCKLIST_PREF_BRANCH "gfx.blacklist."
+#define SUGGESTED_VERSION_PREF BLOCKLIST_PREF_BRANCH "suggested-driver-version"
+
+static const char* GetPrefNameForFeature(int32_t aFeature) {
+  const char* name = nullptr;
+  switch (aFeature) {
+    case nsIGfxInfo::FEATURE_DIRECT2D:
+      name = BLOCKLIST_PREF_BRANCH "direct2d";
+      break;
+    case nsIGfxInfo::FEATURE_DIRECT3D_9_LAYERS:
+      name = BLOCKLIST_PREF_BRANCH "layers.direct3d9";
+      break;
+    case nsIGfxInfo::FEATURE_DIRECT3D_10_LAYERS:
+      name = BLOCKLIST_PREF_BRANCH "layers.direct3d10";
+      break;
+    case nsIGfxInfo::FEATURE_DIRECT3D_10_1_LAYERS:
+      name = BLOCKLIST_PREF_BRANCH "layers.direct3d10-1";
+      break;
+    case nsIGfxInfo::FEATURE_DIRECT3D_11_LAYERS:
+      name = BLOCKLIST_PREF_BRANCH "layers.direct3d11";
+      break;
+    case nsIGfxInfo::FEATURE_DIRECT3D_11_ANGLE:
+      name = BLOCKLIST_PREF_BRANCH "direct3d11angle";
+      break;
+    case nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING:
+      name = BLOCKLIST_PREF_BRANCH "hardwarevideodecoding";
+      break;
+    case nsIGfxInfo::FEATURE_OPENGL_LAYERS:
+      name = BLOCKLIST_PREF_BRANCH "layers.opengl";
+      break;
+    case nsIGfxInfo::FEATURE_WEBGL_OPENGL:
+      name = BLOCKLIST_PREF_BRANCH "webgl.opengl";
+      break;
+    case nsIGfxInfo::FEATURE_WEBGL_ANGLE:
+      name = BLOCKLIST_PREF_BRANCH "webgl.angle";
+      break;
+    case nsIGfxInfo::UNUSED_FEATURE_WEBGL_MSAA:
+      name = BLOCKLIST_PREF_BRANCH "webgl.msaa";
+      break;
+    case nsIGfxInfo::FEATURE_STAGEFRIGHT:
+      name = BLOCKLIST_PREF_BRANCH "stagefright";
+      break;
+    case nsIGfxInfo::FEATURE_WEBRTC_HW_ACCELERATION_H264:
+      name = BLOCKLIST_PREF_BRANCH "webrtc.hw.acceleration.h264";
+      break;
+    case nsIGfxInfo::FEATURE_WEBRTC_HW_ACCELERATION_ENCODE:
+      name = BLOCKLIST_PREF_BRANCH "webrtc.hw.acceleration.encode";
+      break;
+    case nsIGfxInfo::FEATURE_WEBRTC_HW_ACCELERATION_DECODE:
+      name = BLOCKLIST_PREF_BRANCH "webrtc.hw.acceleration.decode";
+      break;
+    case nsIGfxInfo::FEATURE_CANVAS2D_ACCELERATION:
+      name = BLOCKLIST_PREF_BRANCH "canvas2d.acceleration";
+      break;
+    case nsIGfxInfo::FEATURE_DX_INTEROP2:
+      name = BLOCKLIST_PREF_BRANCH "dx.interop2";
+      break;
+    case nsIGfxInfo::FEATURE_GPU_PROCESS:
+      name = BLOCKLIST_PREF_BRANCH "gpu.process";
+      break;
+    case nsIGfxInfo::FEATURE_WEBGL2:
+      name = BLOCKLIST_PREF_BRANCH "webgl2";
+      break;
+    case nsIGfxInfo::FEATURE_D3D11_KEYED_MUTEX:
+      name = BLOCKLIST_PREF_BRANCH "d3d11.keyed.mutex";
+      break;
+    case nsIGfxInfo::FEATURE_WEBRENDER:
+      name = BLOCKLIST_PREF_BRANCH "webrender";
+      break;
+    case nsIGfxInfo::FEATURE_WEBRENDER_COMPOSITOR:
+      name = BLOCKLIST_PREF_BRANCH "webrender.compositor";
+      break;
+    case nsIGfxInfo::FEATURE_DX_NV12:
+      name = BLOCKLIST_PREF_BRANCH "dx.nv12";
+      break;
+    case nsIGfxInfo::FEATURE_DX_P010:
+      name = BLOCKLIST_PREF_BRANCH "dx.p010";
+      break;
+    case nsIGfxInfo::FEATURE_DX_P016:
+      name = BLOCKLIST_PREF_BRANCH "dx.p016";
+      break;
+    case nsIGfxInfo::FEATURE_VP8_HW_DECODE:
+      name = BLOCKLIST_PREF_BRANCH "vp8.hw-decode";
+      break;
+    case nsIGfxInfo::FEATURE_VP9_HW_DECODE:
+      name = BLOCKLIST_PREF_BRANCH "vp9.hw-decode";
+      break;
+    case nsIGfxInfo::FEATURE_GL_SWIZZLE:
+      name = BLOCKLIST_PREF_BRANCH "gl.swizzle";
+      break;
+    case nsIGfxInfo::FEATURE_WEBRENDER_SCISSORED_CACHE_CLEARS:
+      name = BLOCKLIST_PREF_BRANCH "webrender.scissored_cache_clears";
+      break;
+    case nsIGfxInfo::FEATURE_ALLOW_WEBGL_OUT_OF_PROCESS:
+      name = BLOCKLIST_PREF_BRANCH "webgl.allow-oop";
+      break;
+    case nsIGfxInfo::FEATURE_THREADSAFE_GL:
+      name = BLOCKLIST_PREF_BRANCH "gl.threadsafe";
+      break;
+    case nsIGfxInfo::FEATURE_WEBRENDER_OPTIMIZED_SHADERS:
+      name = BLOCKLIST_PREF_BRANCH "webrender.optimized-shaders";
+      break;
+    case nsIGfxInfo::FEATURE_X11_EGL:
+      name = BLOCKLIST_PREF_BRANCH "x11.egl";
+      break;
+    case nsIGfxInfo::FEATURE_DMABUF:
+      name = BLOCKLIST_PREF_BRANCH "dmabuf";
+      break;
+    case nsIGfxInfo::FEATURE_WEBGPU:
+      name = BLOCKLIST_PREF_BRANCH "webgpu";
+      break;
+    case nsIGfxInfo::FEATURE_VIDEO_OVERLAY:
+      name = BLOCKLIST_PREF_BRANCH "video-overlay";
+      break;
+    case nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY:
+      name = BLOCKLIST_PREF_BRANCH "hw-video-zero-copy";
+      break;
+    case nsIGfxInfo::FEATURE_WEBRENDER_SHADER_CACHE:
+      name = BLOCKLIST_PREF_BRANCH "webrender.program-binary-disk";
+      break;
+    case nsIGfxInfo::FEATURE_WEBRENDER_PARTIAL_PRESENT:
+      name = BLOCKLIST_PREF_BRANCH "webrender.partial-present";
+      break;
+    case nsIGfxInfo::FEATURE_DMABUF_SURFACE_EXPORT:
+      name = BLOCKLIST_PREF_BRANCH "dmabuf.surface-export";
+      break;
+    case nsIGfxInfo::FEATURE_REUSE_DECODER_DEVICE:
+      name = BLOCKLIST_PREF_BRANCH "reuse-decoder-device";
+      break;
+    case nsIGfxInfo::FEATURE_BACKDROP_FILTER:
+      name = BLOCKLIST_PREF_BRANCH "backdrop.filter";
+      break;
+    case nsIGfxInfo::FEATURE_ACCELERATED_CANVAS2D:
+      name = BLOCKLIST_PREF_BRANCH "accelerated-canvas2d";
+      break;
+    case nsIGfxInfo::FEATURE_H264_HW_DECODE:
+      name = BLOCKLIST_PREF_BRANCH "h264.hw-decode";
+      break;
+    case nsIGfxInfo::FEATURE_AV1_HW_DECODE:
+      name = BLOCKLIST_PREF_BRANCH "av1.hw-decode";
+      break;
+    case nsIGfxInfo::FEATURE_VIDEO_SOFTWARE_OVERLAY:
+      name = BLOCKLIST_PREF_BRANCH "video-software-overlay";
+      break;
+    case nsIGfxInfo::FEATURE_WEBGL_USE_HARDWARE:
+      name = BLOCKLIST_PREF_BRANCH "webgl-use-hardware";
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE("Unexpected nsIGfxInfo feature?!");
+      break;
+  }
+
+  return name;
+}
+
+// Returns the value of the pref for the relevant feature in aValue.
+// If the pref doesn't exist, aValue is not touched, and returns false.
+static bool GetPrefValueForFeature(int32_t aFeature, int32_t& aValue,
+                                   nsACString& aFailureId) {
+  const char* prefname = GetPrefNameForFeature(aFeature);
+  if (!prefname) return false;
+
+  aValue = nsIGfxInfo::FEATURE_STATUS_UNKNOWN;
+  if (!NS_SUCCEEDED(Preferences::GetInt(prefname, &aValue))) {
+    return false;
+  }
+
+  if (aValue == nsIGfxInfo::FEATURE_DENIED) {
+    // We should never see the DENIED status with the downloadable blocklist.
+    return false;
+  }
+
+  nsCString failureprefname(prefname);
+  failureprefname += ".failureid";
+  nsAutoCString failureValue;
+  nsresult rv = Preferences::GetCString(failureprefname.get(), failureValue);
+  if (NS_SUCCEEDED(rv)) {
+    aFailureId = failureValue.get();
+  } else {
+    aFailureId = "FEATURE_FAILURE_BLOCKLIST_PREF";
+  }
+
+  return true;
+}
+
+static void SetPrefValueForFeature(int32_t aFeature, int32_t aValue,
+                                   const nsACString& aFailureId) {
+  const char* prefname = GetPrefNameForFeature(aFeature);
+  if (!prefname) return;
+  if (XRE_IsParentProcess()) {
+    GfxInfoBase::sFeatureStatus = nullptr;
+  }
+
+  Preferences::SetInt(prefname, aValue);
+  if (!aFailureId.IsEmpty()) {
+    nsAutoCString failureprefname(prefname);
+    failureprefname += ".failureid";
+    Preferences::SetCString(failureprefname.get(), aFailureId);
+  }
+}
+
+static void RemovePrefForFeature(int32_t aFeature) {
+  const char* prefname = GetPrefNameForFeature(aFeature);
+  if (!prefname) return;
+
+  if (XRE_IsParentProcess()) {
+    GfxInfoBase::sFeatureStatus = nullptr;
+  }
+  Preferences::ClearUser(prefname);
+}
+
+static bool GetPrefValueForDriverVersion(nsCString& aVersion) {
+  return NS_SUCCEEDED(
+      Preferences::GetCString(SUGGESTED_VERSION_PREF, aVersion));
+}
+
+static void SetPrefValueForDriverVersion(const nsAString& aVersion) {
+  Preferences::SetString(SUGGESTED_VERSION_PREF, aVersion);
+}
+
+static void RemovePrefForDriverVersion() {
+  Preferences::ClearUser(SUGGESTED_VERSION_PREF);
+}
+
+static OperatingSystem BlocklistOSToOperatingSystem(const nsAString& os) {
+  if (os.EqualsLiteral("WINNT 6.1")) {
+    return OperatingSystem::Windows7;
+  }
+  if (os.EqualsLiteral("WINNT 6.2")) {
+    return OperatingSystem::Windows8;
+  }
+  if (os.EqualsLiteral("WINNT 6.3")) {
+    return OperatingSystem::Windows8_1;
+  }
+  if (os.EqualsLiteral("WINNT 10.0")) {
+    return OperatingSystem::Windows10;
+  }
+  if (os.EqualsLiteral("Linux")) {
+    return OperatingSystem::Linux;
+  }
+  if (os.EqualsLiteral("Darwin 9")) {
+    return OperatingSystem::OSX10_5;
+  }
+  if (os.EqualsLiteral("Darwin 10")) {
+    return OperatingSystem::OSX10_6;
+  }
+  if (os.EqualsLiteral("Darwin 11")) {
+    return OperatingSystem::OSX10_7;
+  }
+  if (os.EqualsLiteral("Darwin 12")) {
+    return OperatingSystem::OSX10_8;
+  }
+  if (os.EqualsLiteral("Darwin 13")) {
+    return OperatingSystem::OSX10_9;
+  }
+  if (os.EqualsLiteral("Darwin 14")) {
+    return OperatingSystem::OSX10_10;
+  }
+  if (os.EqualsLiteral("Darwin 15")) {
+    return OperatingSystem::OSX10_11;
+  }
+  if (os.EqualsLiteral("Darwin 16")) {
+    return OperatingSystem::OSX10_12;
+  }
+  if (os.EqualsLiteral("Darwin 17")) {
+    return OperatingSystem::OSX10_13;
+  }
+  if (os.EqualsLiteral("Darwin 18")) {
+    return OperatingSystem::OSX10_14;
+  }
+  if (os.EqualsLiteral("Darwin 19")) {
+    return OperatingSystem::OSX10_15;
+  }
+  if (os.EqualsLiteral("Darwin 20")) {
+    return OperatingSystem::OSX11_0;
+  }
+  if (os.EqualsLiteral("Android")) {
+    return OperatingSystem::Android;
+    // For historical reasons, "All" in blocklist means "All Windows"
+  }
+  if (os.EqualsLiteral("All")) {
+    return OperatingSystem::Windows;
+  }
+  if (os.EqualsLiteral("Darwin")) {
+    return OperatingSystem::OSX;
+  }
+
+  return OperatingSystem::Unknown;
+}
+
+static GfxDeviceFamily* BlocklistDevicesToDeviceFamily(
+    nsTArray<nsCString>& devices) {
+  if (devices.Length() == 0) return nullptr;
+
+  // For each device, get its device ID, and return a freshly-allocated
+  // GfxDeviceFamily with the contents of that array.
+  GfxDeviceFamily* deviceIds = new GfxDeviceFamily;
+
+  for (uint32_t i = 0; i < devices.Length(); ++i) {
+    // We make sure we don't add any "empty" device entries to the array, so
+    // we don't need to check if devices[i] is empty.
+    deviceIds->Append(NS_ConvertUTF8toUTF16(devices[i]));
+  }
+
+  return deviceIds;
+}
+
+static int32_t BlocklistFeatureToGfxFeature(const nsAString& aFeature) {
+  MOZ_ASSERT(!aFeature.IsEmpty());
+  if (aFeature.EqualsLiteral("DIRECT2D")) {
+    return nsIGfxInfo::FEATURE_DIRECT2D;
+  }
+  if (aFeature.EqualsLiteral("DIRECT3D_9_LAYERS")) {
+    return nsIGfxInfo::FEATURE_DIRECT3D_9_LAYERS;
+  }
+  if (aFeature.EqualsLiteral("DIRECT3D_10_LAYERS")) {
+    return nsIGfxInfo::FEATURE_DIRECT3D_10_LAYERS;
+  }
+  if (aFeature.EqualsLiteral("DIRECT3D_10_1_LAYERS")) {
+    return nsIGfxInfo::FEATURE_DIRECT3D_10_1_LAYERS;
+  }
+  if (aFeature.EqualsLiteral("DIRECT3D_11_LAYERS")) {
+    return nsIGfxInfo::FEATURE_DIRECT3D_11_LAYERS;
+  }
+  if (aFeature.EqualsLiteral("DIRECT3D_11_ANGLE")) {
+    return nsIGfxInfo::FEATURE_DIRECT3D_11_ANGLE;
+  }
+  if (aFeature.EqualsLiteral("HARDWARE_VIDEO_DECODING")) {
+    return nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING;
+  }
+  if (aFeature.EqualsLiteral("OPENGL_LAYERS")) {
+    return nsIGfxInfo::FEATURE_OPENGL_LAYERS;
+  }
+  if (aFeature.EqualsLiteral("WEBGL_OPENGL")) {
+    return nsIGfxInfo::FEATURE_WEBGL_OPENGL;
+  }
+  if (aFeature.EqualsLiteral("WEBGL_ANGLE")) {
+    return nsIGfxInfo::FEATURE_WEBGL_ANGLE;
+  }
+  if (aFeature.EqualsLiteral("WEBGL_MSAA")) {
+    return nsIGfxInfo::UNUSED_FEATURE_WEBGL_MSAA;
+  }
+  if (aFeature.EqualsLiteral("STAGEFRIGHT")) {
+    return nsIGfxInfo::FEATURE_STAGEFRIGHT;
+  }
+  if (aFeature.EqualsLiteral("WEBRTC_HW_ACCELERATION_ENCODE")) {
+    return nsIGfxInfo::FEATURE_WEBRTC_HW_ACCELERATION_ENCODE;
+  }
+  if (aFeature.EqualsLiteral("WEBRTC_HW_ACCELERATION_DECODE")) {
+    return nsIGfxInfo::FEATURE_WEBRTC_HW_ACCELERATION_DECODE;
+  }
+  if (aFeature.EqualsLiteral("WEBRTC_HW_ACCELERATION_H264")) {
+    return nsIGfxInfo::FEATURE_WEBRTC_HW_ACCELERATION_H264;
+  }
+  if (aFeature.EqualsLiteral("CANVAS2D_ACCELERATION")) {
+    return nsIGfxInfo::FEATURE_CANVAS2D_ACCELERATION;
+  }
+  if (aFeature.EqualsLiteral("DX_INTEROP2")) {
+    return nsIGfxInfo::FEATURE_DX_INTEROP2;
+  }
+  if (aFeature.EqualsLiteral("GPU_PROCESS")) {
+    return nsIGfxInfo::FEATURE_GPU_PROCESS;
+  }
+  if (aFeature.EqualsLiteral("WEBGL2")) {
+    return nsIGfxInfo::FEATURE_WEBGL2;
+  }
+  if (aFeature.EqualsLiteral("D3D11_KEYED_MUTEX")) {
+    return nsIGfxInfo::FEATURE_D3D11_KEYED_MUTEX;
+  }
+  if (aFeature.EqualsLiteral("WEBRENDER")) {
+    return nsIGfxInfo::FEATURE_WEBRENDER;
+  }
+  if (aFeature.EqualsLiteral("WEBRENDER_COMPOSITOR")) {
+    return nsIGfxInfo::FEATURE_WEBRENDER_COMPOSITOR;
+  }
+  if (aFeature.EqualsLiteral("DX_NV12")) {
+    return nsIGfxInfo::FEATURE_DX_NV12;
+  }
+  if (aFeature.EqualsLiteral("VP8_HW_DECODE")) {
+    return nsIGfxInfo::FEATURE_VP8_HW_DECODE;
+  }
+  if (aFeature.EqualsLiteral("VP9_HW_DECODE")) {
+    return nsIGfxInfo::FEATURE_VP9_HW_DECODE;
+  }
+  if (aFeature.EqualsLiteral("GL_SWIZZLE")) {
+    return nsIGfxInfo::FEATURE_GL_SWIZZLE;
+  }
+  if (aFeature.EqualsLiteral("WEBRENDER_SCISSORED_CACHE_CLEARS")) {
+    return nsIGfxInfo::FEATURE_WEBRENDER_SCISSORED_CACHE_CLEARS;
+  }
+  if (aFeature.EqualsLiteral("ALLOW_WEBGL_OUT_OF_PROCESS")) {
+    return nsIGfxInfo::FEATURE_ALLOW_WEBGL_OUT_OF_PROCESS;
+  }
+  if (aFeature.EqualsLiteral("THREADSAFE_GL")) {
+    return nsIGfxInfo::FEATURE_THREADSAFE_GL;
+  }
+  if (aFeature.EqualsLiteral("X11_EGL")) {
+    return nsIGfxInfo::FEATURE_X11_EGL;
+  }
+  if (aFeature.EqualsLiteral("DMABUF")) {
+    return nsIGfxInfo::FEATURE_DMABUF;
+  }
+  if (aFeature.EqualsLiteral("WEBGPU")) {
+    return nsIGfxInfo::FEATURE_WEBGPU;
+  }
+  if (aFeature.EqualsLiteral("VIDEO_OVERLAY")) {
+    return nsIGfxInfo::FEATURE_VIDEO_OVERLAY;
+  }
+  if (aFeature.EqualsLiteral("HW_DECODED_VIDEO_ZERO_COPY")) {
+    return nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY;
+  }
+  if (aFeature.EqualsLiteral("REUSE_DECODER_DEVICE")) {
+    return nsIGfxInfo::FEATURE_REUSE_DECODER_DEVICE;
+  }
+  if (aFeature.EqualsLiteral("WEBRENDER_PARTIAL_PRESENT")) {
+    return nsIGfxInfo::FEATURE_WEBRENDER_PARTIAL_PRESENT;
+  }
+  if (aFeature.EqualsLiteral("BACKDROP_FILTER")) {
+    return nsIGfxInfo::FEATURE_BACKDROP_FILTER;
+  }
+  if (aFeature.EqualsLiteral("ACCELERATED_CANVAS2D")) {
+    return nsIGfxInfo::FEATURE_ACCELERATED_CANVAS2D;
+  }
+  if (aFeature.EqualsLiteral("ALL")) {
+    return GfxDriverInfo::allFeatures;
+  }
+  if (aFeature.EqualsLiteral("OPTIONAL")) {
+    return GfxDriverInfo::optionalFeatures;
+  }
+
+  // If we don't recognize the feature, it may be new, and something
+  // this version doesn't understand.  So, nothing to do.  This is
+  // different from feature not being specified at all, in which case
+  // this method should not get called and we should continue with the
+  // "optional features" blocklisting.
+  return 0;
+}
+
+static int32_t BlocklistFeatureStatusToGfxFeatureStatus(
+    const nsAString& aStatus) {
+  if (aStatus.EqualsLiteral("STATUS_OK")) {
+    return nsIGfxInfo::FEATURE_STATUS_OK;
+  }
+  if (aStatus.EqualsLiteral("BLOCKED_DRIVER_VERSION")) {
+    return nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION;
+  }
+  if (aStatus.EqualsLiteral("BLOCKED_DEVICE")) {
+    return nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+  }
+  if (aStatus.EqualsLiteral("DISCOURAGED")) {
+    return nsIGfxInfo::FEATURE_DISCOURAGED;
+  }
+  if (aStatus.EqualsLiteral("BLOCKED_OS_VERSION")) {
+    return nsIGfxInfo::FEATURE_BLOCKED_OS_VERSION;
+  }
+  if (aStatus.EqualsLiteral("DENIED")) {
+    return nsIGfxInfo::FEATURE_DENIED;
+  }
+  if (aStatus.EqualsLiteral("ALLOW_QUALIFIED")) {
+    return nsIGfxInfo::FEATURE_ALLOW_QUALIFIED;
+  }
+  if (aStatus.EqualsLiteral("ALLOW_ALWAYS")) {
+    return nsIGfxInfo::FEATURE_ALLOW_ALWAYS;
+  }
+
+  // Do not allow it to set STATUS_UNKNOWN.  Also, we are not
+  // expecting the "mismatch" status showing up here.
+
+  return nsIGfxInfo::FEATURE_STATUS_OK;
+}
+
+static VersionComparisonOp BlocklistComparatorToComparisonOp(
+    const nsAString& op) {
+  if (op.EqualsLiteral("LESS_THAN")) {
+    return DRIVER_LESS_THAN;
+  }
+  if (op.EqualsLiteral("BUILD_ID_LESS_THAN")) {
+    return DRIVER_BUILD_ID_LESS_THAN;
+  }
+  if (op.EqualsLiteral("LESS_THAN_OR_EQUAL")) {
+    return DRIVER_LESS_THAN_OR_EQUAL;
+  }
+  if (op.EqualsLiteral("BUILD_ID_LESS_THAN_OR_EQUAL")) {
+    return DRIVER_BUILD_ID_LESS_THAN_OR_EQUAL;
+  }
+  if (op.EqualsLiteral("GREATER_THAN")) {
+    return DRIVER_GREATER_THAN;
+  }
+  if (op.EqualsLiteral("GREATER_THAN_OR_EQUAL")) {
+    return DRIVER_GREATER_THAN_OR_EQUAL;
+  }
+  if (op.EqualsLiteral("EQUAL")) {
+    return DRIVER_EQUAL;
+  }
+  if (op.EqualsLiteral("NOT_EQUAL")) {
+    return DRIVER_NOT_EQUAL;
+  }
+  if (op.EqualsLiteral("BETWEEN_EXCLUSIVE")) {
+    return DRIVER_BETWEEN_EXCLUSIVE;
+  }
+  if (op.EqualsLiteral("BETWEEN_INCLUSIVE")) {
+    return DRIVER_BETWEEN_INCLUSIVE;
+  }
+  if (op.EqualsLiteral("BETWEEN_INCLUSIVE_START")) {
+    return DRIVER_BETWEEN_INCLUSIVE_START;
+  }
+
+  return DRIVER_COMPARISON_IGNORED;
+}
+
+/*
+  Deserialize Blocklist entries from string.
+  e.g:
+  os:WINNT 6.0\tvendor:0x8086\tdevices:0x2582,0x2782\tfeature:DIRECT3D_10_LAYERS\tfeatureStatus:BLOCKED_DRIVER_VERSION\tdriverVersion:8.52.322.2202\tdriverVersionComparator:LESS_THAN_OR_EQUAL
+*/
+static bool BlocklistEntryToDriverInfo(const nsACString& aBlocklistEntry,
+                                       GfxDriverInfo& aDriverInfo) {
+  // If we get an application version to be zero, something is not working
+  // and we are not going to bother checking the blocklist versions.
+  // See TestGfxWidgets.cpp for how version comparison works.
+  // <versionRange minVersion="42.0a1" maxVersion="45.0"></versionRange>
+  static mozilla::Version zeroV("0");
+  static mozilla::Version appV(GfxInfoBase::GetApplicationVersion().get());
+  if (appV <= zeroV) {
+    gfxCriticalErrorOnce(gfxCriticalError::DefaultOptions(false))
+        << "Invalid application version "
+        << GfxInfoBase::GetApplicationVersion().get();
+  }
+
+  aDriverInfo.mRuleId = "FEATURE_FAILURE_DL_BLOCKLIST_NO_ID"_ns;
+
+  for (const auto& keyValue : aBlocklistEntry.Split('\t')) {
+    nsTArray<nsCString> splitted;
+    ParseString(keyValue, ':', splitted);
+    if (splitted.Length() != 2) {
+      // If we don't recognize the input data, we do not want to proceed.
+      gfxCriticalErrorOnce(CriticalLog::DefaultOptions(false))
+          << "Unrecognized data " << nsCString(keyValue).get();
+      return false;
+    }
+    const nsCString& key = splitted[0];
+    const nsCString& value = splitted[1];
+    NS_ConvertUTF8toUTF16 dataValue(value);
+
+    if (value.Length() == 0) {
+      // Safety check for empty values.
+      gfxCriticalErrorOnce(CriticalLog::DefaultOptions(false))
+          << "Empty value for " << key.get();
+      return false;
+    }
+
+    if (key.EqualsLiteral("blockID")) {
+      nsCString blockIdStr = "FEATURE_FAILURE_DL_BLOCKLIST_"_ns + value;
+      aDriverInfo.mRuleId = blockIdStr.get();
+    } else if (key.EqualsLiteral("os")) {
+      aDriverInfo.mOperatingSystem = BlocklistOSToOperatingSystem(dataValue);
+    } else if (key.EqualsLiteral("osversion")) {
+      aDriverInfo.mOperatingSystemVersion = strtoul(value.get(), nullptr, 10);
+    } else if (key.EqualsLiteral("windowProtocol")) {
+      aDriverInfo.mWindowProtocol = dataValue;
+    } else if (key.EqualsLiteral("vendor")) {
+      aDriverInfo.mAdapterVendor = dataValue;
+    } else if (key.EqualsLiteral("driverVendor")) {
+      aDriverInfo.mDriverVendor = dataValue;
+    } else if (key.EqualsLiteral("feature")) {
+      aDriverInfo.mFeature = BlocklistFeatureToGfxFeature(dataValue);
+      if (aDriverInfo.mFeature == 0) {
+        // If we don't recognize the feature, we do not want to proceed.
+        gfxWarning() << "Unrecognized feature " << value.get();
+        return false;
+      }
+    } else if (key.EqualsLiteral("featureStatus")) {
+      aDriverInfo.mFeatureStatus =
+          BlocklistFeatureStatusToGfxFeatureStatus(dataValue);
+    } else if (key.EqualsLiteral("driverVersion")) {
+      uint64_t version;
+      if (ParseDriverVersion(dataValue, &version))
+        aDriverInfo.mDriverVersion = version;
+    } else if (key.EqualsLiteral("driverVersionMax")) {
+      uint64_t version;
+      if (ParseDriverVersion(dataValue, &version))
+        aDriverInfo.mDriverVersionMax = version;
+    } else if (key.EqualsLiteral("driverVersionComparator")) {
+      aDriverInfo.mComparisonOp = BlocklistComparatorToComparisonOp(dataValue);
+    } else if (key.EqualsLiteral("model")) {
+      aDriverInfo.mModel = dataValue;
+    } else if (key.EqualsLiteral("product")) {
+      aDriverInfo.mProduct = dataValue;
+    } else if (key.EqualsLiteral("manufacturer")) {
+      aDriverInfo.mManufacturer = dataValue;
+    } else if (key.EqualsLiteral("hardware")) {
+      aDriverInfo.mHardware = dataValue;
+    } else if (key.EqualsLiteral("versionRange")) {
+      nsTArray<nsCString> versionRange;
+      ParseString(value, ',', versionRange);
+      if (versionRange.Length() != 2) {
+        gfxCriticalErrorOnce(CriticalLog::DefaultOptions(false))
+            << "Unrecognized versionRange " << value.get();
+        return false;
+      }
+      const nsCString& minValue = versionRange[0];
+      const nsCString& maxValue = versionRange[1];
+
+      mozilla::Version minV(minValue.get());
+      mozilla::Version maxV(maxValue.get());
+
+      if (minV > zeroV && !(appV >= minV)) {
+        // The version of the application is less than the minimal version
+        // this blocklist entry applies to, so we can just ignore it by
+        // returning false and letting the caller deal with it.
+        return false;
+      }
+      if (maxV > zeroV && !(appV <= maxV)) {
+        // The version of the application is more than the maximal version
+        // this blocklist entry applies to, so we can just ignore it by
+        // returning false and letting the caller deal with it.
+        return false;
+      }
+    } else if (key.EqualsLiteral("devices")) {
+      nsTArray<nsCString> devices;
+      ParseString(value, ',', devices);
+      GfxDeviceFamily* deviceIds = BlocklistDevicesToDeviceFamily(devices);
+      if (deviceIds) {
+        // Get GfxDriverInfo to adopt the devices array we created.
+        aDriverInfo.mDeleteDevices = true;
+        aDriverInfo.mDevices = deviceIds;
+      }
+    }
+    // We explicitly ignore unknown elements.
+  }
+
+  return true;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::Observe(nsISupports* aSubject, const char* aTopic,
+                     const char16_t* aData) {
+  if (strcmp(aTopic, "blocklist-data-gfxItems") == 0) {
+    nsTArray<GfxDriverInfo> driverInfo;
+    NS_ConvertUTF16toUTF8 utf8Data(aData);
+
+    for (const auto& blocklistEntry : utf8Data.Split('\n')) {
+      GfxDriverInfo di;
+      if (BlocklistEntryToDriverInfo(blocklistEntry, di)) {
+        // XXX Changing this to driverInfo.AppendElement(di) causes leaks.
+        // Probably some non-standard semantics of the copy/move operations?
+        *driverInfo.AppendElement() = di;
+        // Prevent di falling out of scope from destroying the devices.
+        di.mDeleteDevices = false;
+      } else {
+        driverInfo.AppendElement();
+      }
+    }
+
+    EvaluateDownloadedBlocklist(driverInfo);
+  }
+
+  return NS_OK;
+}
+
+GfxInfoBase::GfxInfoBase() : mScreenPixels(INT64_MAX), mMutex("GfxInfoBase") {}
+
+GfxInfoBase::~GfxInfoBase() = default;
+
+nsresult GfxInfoBase::Init() {
+  InitGfxDriverInfoShutdownObserver();
+
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (os) {
+    os->AddObserver(this, "blocklist-data-gfxItems", true);
+  }
+
+  return NS_OK;
+}
+
+void GfxInfoBase::GetData() {
+  if (mScreenPixels != INT64_MAX) {
+    // Already initialized.
+    return;
+  }
+
+  ScreenManager::GetSingleton().GetTotalScreenPixels(&mScreenPixels);
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetFeatureStatus(int32_t aFeature, nsACString& aFailureId,
+                              int32_t* aStatus) {
+  // Ignore the gfx.blocklist.all pref on release and beta.
+#if defined(RELEASE_OR_BETA)
+  int32_t blocklistAll = 0;
+#else
+  int32_t blocklistAll = StaticPrefs::gfx_blocklist_all_AtStartup();
+#endif
+  if (blocklistAll > 0) {
+    gfxCriticalErrorOnce(gfxCriticalError::DefaultOptions(false))
+        << "Forcing blocklisting all features";
+    *aStatus = FEATURE_BLOCKED_DEVICE;
+    aFailureId = "FEATURE_FAILURE_BLOCK_ALL";
+    return NS_OK;
+  }
+
+  if (blocklistAll < 0) {
+    gfxCriticalErrorOnce(gfxCriticalError::DefaultOptions(false))
+        << "Ignoring any feature blocklisting.";
+    *aStatus = FEATURE_STATUS_OK;
+    return NS_OK;
+  }
+
+  // This is how we evaluate the downloadable blocklist. If there is no pref,
+  // then we will fallback to checking the static blocklist.
+  if (GetPrefValueForFeature(aFeature, *aStatus, aFailureId)) {
+    return NS_OK;
+  }
+
+  if (XRE_IsContentProcess() || XRE_IsGPUProcess()) {
+    // Use the cached data received from the parent process.
+    MOZ_ASSERT(sFeatureStatus);
+    bool success = false;
+    for (const auto& fs : *sFeatureStatus) {
+      if (fs.feature() == aFeature) {
+        aFailureId = fs.failureId();
+        *aStatus = fs.status();
+        success = true;
+        break;
+      }
+    }
+    return success ? NS_OK : NS_ERROR_FAILURE;
+  }
+
+  nsString version;
+  nsTArray<GfxDriverInfo> driverInfo;
+  nsresult rv =
+      GetFeatureStatusImpl(aFeature, aStatus, version, driverInfo, aFailureId);
+  return rv;
+}
+
+nsTArray<gfx::GfxInfoFeatureStatus> GfxInfoBase::GetAllFeatures() {
+  MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
+  if (!sFeatureStatus) {
+    InitFeatureStatus(new nsTArray<gfx::GfxInfoFeatureStatus>());
+    for (int32_t i = 1; i <= nsIGfxInfo::FEATURE_MAX_VALUE; ++i) {
+      int32_t status = 0;
+      nsAutoCString failureId;
+      GetFeatureStatus(i, failureId, &status);
+      gfx::GfxInfoFeatureStatus gfxFeatureStatus;
+      gfxFeatureStatus.feature() = i;
+      gfxFeatureStatus.status() = status;
+      gfxFeatureStatus.failureId() = failureId;
+      sFeatureStatus->AppendElement(gfxFeatureStatus);
+    }
+  }
+
+  nsTArray<gfx::GfxInfoFeatureStatus> features;
+  for (const auto& status : *sFeatureStatus) {
+    gfx::GfxInfoFeatureStatus copy = status;
+    features.AppendElement(copy);
+  }
+  return features;
+}
+
+inline bool MatchingAllowStatus(int32_t aStatus) {
+  switch (aStatus) {
+    case nsIGfxInfo::FEATURE_ALLOW_ALWAYS:
+    case nsIGfxInfo::FEATURE_ALLOW_QUALIFIED:
+      return true;
+    default:
+      return false;
+  }
+}
+
+// Matching OS go somewhat beyond the simple equality check because of the
+// "All Windows" and "All OS X" variations.
+//
+// aBlockedOS is describing the system(s) we are trying to block.
+// aSystemOS is describing the system we are running on.
+//
+// aSystemOS should not be "Windows" or "OSX" - it should be set to
+// a particular version instead.
+// However, it is valid for aBlockedOS to be one of those generic values,
+// as we could be blocking all of the versions.
+inline bool MatchingOperatingSystems(OperatingSystem aBlockedOS,
+                                     OperatingSystem aSystemOS,
+                                     uint32_t aSystemOSBuild) {
+  MOZ_ASSERT(aSystemOS != OperatingSystem::Windows &&
+             aSystemOS != OperatingSystem::OSX);
+
+  // If the block entry OS is unknown, it doesn't match
+  if (aBlockedOS == OperatingSystem::Unknown) {
+    return false;
+  }
+
+#if defined(XP_WIN)
+  if (aBlockedOS == OperatingSystem::Windows) {
+    // We do want even "unknown" aSystemOS to fall under "all windows"
+    return true;
+  }
+
+  constexpr uint32_t kMinWin10BuildNumber = 18362;
+  if (aBlockedOS == OperatingSystem::RecentWindows10 &&
+      aSystemOS == OperatingSystem::Windows10) {
+    // For allowlist purposes, we sometimes want to restrict to only recent
+    // versions of Windows 10. This is a bit of a kludge but easier than adding
+    // complicated blocklist infrastructure for build ID comparisons like driver
+    // versions.
+    return aSystemOSBuild >= kMinWin10BuildNumber;
+  }
+
+  if (aBlockedOS == OperatingSystem::NotRecentWindows10) {
+    if (aSystemOS == OperatingSystem::Windows10) {
+      return aSystemOSBuild < kMinWin10BuildNumber;
+    } else {
+      return true;
+    }
+  }
+#endif
+
+#if defined(XP_MACOSX)
+  if (aBlockedOS == OperatingSystem::OSX) {
+    // We do want even "unknown" aSystemOS to fall under "all OS X"
+    return true;
+  }
+#endif
+
+  return aSystemOS == aBlockedOS;
+}
+
+inline bool MatchingBattery(BatteryStatus aBatteryStatus, bool aHasBattery) {
+  switch (aBatteryStatus) {
+    case BatteryStatus::All:
+      return true;
+    case BatteryStatus::None:
+      return !aHasBattery;
+    case BatteryStatus::Present:
+      return aHasBattery;
+  }
+
+  MOZ_ASSERT_UNREACHABLE("bad battery status");
+  return false;
+}
+
+inline bool MatchingScreenSize(ScreenSizeStatus aScreenStatus,
+                               int64_t aScreenPixels) {
+  constexpr int64_t kMaxSmallPixels = 2304000;   // 1920x1200
+  constexpr int64_t kMaxMediumPixels = 4953600;  // 3440x1440
+
+  switch (aScreenStatus) {
+    case ScreenSizeStatus::All:
+      return true;
+    case ScreenSizeStatus::Small:
+      return aScreenPixels <= kMaxSmallPixels;
+    case ScreenSizeStatus::SmallAndMedium:
+      return aScreenPixels <= kMaxMediumPixels;
+    case ScreenSizeStatus::Medium:
+      return aScreenPixels > kMaxSmallPixels &&
+             aScreenPixels <= kMaxMediumPixels;
+    case ScreenSizeStatus::MediumAndLarge:
+      return aScreenPixels > kMaxSmallPixels;
+    case ScreenSizeStatus::Large:
+      return aScreenPixels > kMaxMediumPixels;
+  }
+
+  MOZ_ASSERT_UNREACHABLE("bad screen status");
+  return false;
+}
+
+int32_t GfxInfoBase::FindBlocklistedDeviceInList(
+    const nsTArray<GfxDriverInfo>& info, nsAString& aSuggestedVersion,
+    int32_t aFeature, nsACString& aFailureId, OperatingSystem os,
+    bool aForAllowing) {
+  int32_t status = nsIGfxInfo::FEATURE_STATUS_UNKNOWN;
+
+  // Some properties are not available on all platforms.
+  nsAutoString windowProtocol;
+  nsresult rv = GetWindowProtocol(windowProtocol);
+  if (NS_FAILED(rv) && rv != NS_ERROR_NOT_IMPLEMENTED) {
+    return 0;
+  }
+
+  bool hasBattery = false;
+  rv = GetHasBattery(&hasBattery);
+  if (NS_FAILED(rv) && rv != NS_ERROR_NOT_IMPLEMENTED) {
+    return 0;
+  }
+
+  uint32_t osBuild = OperatingSystemBuild();
+
+  // Get the adapters once then reuse below
+  nsAutoString adapterVendorID[2];
+  nsAutoString adapterDeviceID[2];
+  nsAutoString adapterDriverVendor[2];
+  nsAutoString adapterDriverVersionString[2];
+  bool adapterInfoFailed[2];
+
+  adapterInfoFailed[0] =
+      (NS_FAILED(GetAdapterVendorID(adapterVendorID[0])) ||
+       NS_FAILED(GetAdapterDeviceID(adapterDeviceID[0])) ||
+       NS_FAILED(GetAdapterDriverVendor(adapterDriverVendor[0])) ||
+       NS_FAILED(GetAdapterDriverVersion(adapterDriverVersionString[0])));
+  adapterInfoFailed[1] =
+      (NS_FAILED(GetAdapterVendorID2(adapterVendorID[1])) ||
+       NS_FAILED(GetAdapterDeviceID2(adapterDeviceID[1])) ||
+       NS_FAILED(GetAdapterDriverVendor2(adapterDriverVendor[1])) ||
+       NS_FAILED(GetAdapterDriverVersion2(adapterDriverVersionString[1])));
+  // No point in going on if we don't have adapter info
+  if (adapterInfoFailed[0] && adapterInfoFailed[1]) {
+    return 0;
+  }
+
+#if defined(XP_WIN) || defined(ANDROID) || defined(MOZ_WIDGET_GTK)
+  uint64_t driverVersion[2] = {0, 0};
+  if (!adapterInfoFailed[0]) {
+    ParseDriverVersion(adapterDriverVersionString[0], &driverVersion[0]);
+  }
+  if (!adapterInfoFailed[1]) {
+    ParseDriverVersion(adapterDriverVersionString[1], &driverVersion[1]);
+  }
+#endif
+
+  uint32_t i = 0;
+  for (; i < info.Length(); i++) {
+    // If the status is FEATURE_ALLOW_*, then it is for the allowlist, not
+    // blocklisting. Only consider entries for our search mode.
+    if (MatchingAllowStatus(info[i].mFeatureStatus) != aForAllowing) {
+      continue;
+    }
+
+    // If we don't have the info for this GPU, no need to check further.
+    // It is unclear that we would ever have a mixture of 1st and 2nd
+    // GPU, but leaving the code in for that possibility for now.
+    // (Actually, currently mGpu2 will never be true, so this can
+    // be optimized out.)
+    uint32_t infoIndex = info[i].mGpu2 ? 1 : 0;
+    if (adapterInfoFailed[infoIndex]) {
+      continue;
+    }
+
+    // Do the operating system check first, no point in getting the driver
+    // info if we won't need to use it.
+    if (!MatchingOperatingSystems(info[i].mOperatingSystem, os, osBuild)) {
+      continue;
+    }
+
+    if (info[i].mOperatingSystemVersion &&
+        info[i].mOperatingSystemVersion != OperatingSystemVersion()) {
+      continue;
+    }
+
+    if (!MatchingBattery(info[i].mBattery, hasBattery)) {
+      continue;
+    }
+
+    if (!MatchingScreenSize(info[i].mScreen, mScreenPixels)) {
+      continue;
+    }
+
+    if (!DoesWindowProtocolMatch(info[i].mWindowProtocol, windowProtocol)) {
+      continue;
+    }
+
+    if (!DoesVendorMatch(info[i].mAdapterVendor, adapterVendorID[infoIndex])) {
+      continue;
+    }
+
+    if (!DoesDriverVendorMatch(info[i].mDriverVendor,
+                               adapterDriverVendor[infoIndex])) {
+      continue;
+    }
+
+    if (info[i].mDevices && !info[i].mDevices->IsEmpty()) {
+      nsresult rv = info[i].mDevices->Contains(adapterDeviceID[infoIndex]);
+      if (rv == NS_ERROR_NOT_AVAILABLE) {
+        // Not found
+        continue;
+      }
+      if (rv != NS_OK) {
+        // Failed to search, allowlist should not match, blocklist should match
+        // for safety reasons
+        if (aForAllowing) {
+          continue;
+        }
+        break;
+      }
+    }
+
+    bool match = false;
+
+    if (!info[i].mHardware.IsEmpty() && !info[i].mHardware.Equals(Hardware())) {
+      continue;
+    }
+    if (!info[i].mModel.IsEmpty() && !info[i].mModel.Equals(Model())) {
+      continue;
+    }
+    if (!info[i].mProduct.IsEmpty() && !info[i].mProduct.Equals(Product())) {
+      continue;
+    }
+    if (!info[i].mManufacturer.IsEmpty() &&
+        !info[i].mManufacturer.Equals(Manufacturer())) {
+      continue;
+    }
+
+#if defined(XP_WIN) || defined(ANDROID) || defined(MOZ_WIDGET_GTK)
+    switch (info[i].mComparisonOp) {
+      case DRIVER_LESS_THAN:
+        match = driverVersion[infoIndex] < info[i].mDriverVersion;
+        break;
+      case DRIVER_BUILD_ID_LESS_THAN:
+        match = (driverVersion[infoIndex] & 0xFFFF) < info[i].mDriverVersion;
+        break;
+      case DRIVER_LESS_THAN_OR_EQUAL:
+        match = driverVersion[infoIndex] <= info[i].mDriverVersion;
+        break;
+      case DRIVER_BUILD_ID_LESS_THAN_OR_EQUAL:
+        match = (driverVersion[infoIndex] & 0xFFFF) <= info[i].mDriverVersion;
+        break;
+      case DRIVER_GREATER_THAN:
+        match = driverVersion[infoIndex] > info[i].mDriverVersion;
+        break;
+      case DRIVER_GREATER_THAN_OR_EQUAL:
+        match = driverVersion[infoIndex] >= info[i].mDriverVersion;
+        break;
+      case DRIVER_EQUAL:
+        match = driverVersion[infoIndex] == info[i].mDriverVersion;
+        break;
+      case DRIVER_NOT_EQUAL:
+        match = driverVersion[infoIndex] != info[i].mDriverVersion;
+        break;
+      case DRIVER_BETWEEN_EXCLUSIVE:
+        match = driverVersion[infoIndex] > info[i].mDriverVersion &&
+                driverVersion[infoIndex] < info[i].mDriverVersionMax;
+        break;
+      case DRIVER_BETWEEN_INCLUSIVE:
+        match = driverVersion[infoIndex] >= info[i].mDriverVersion &&
+                driverVersion[infoIndex] <= info[i].mDriverVersionMax;
+        break;
+      case DRIVER_BETWEEN_INCLUSIVE_START:
+        match = driverVersion[infoIndex] >= info[i].mDriverVersion &&
+                driverVersion[infoIndex] < info[i].mDriverVersionMax;
+        break;
+      case DRIVER_COMPARISON_IGNORED:
+        // We don't have a comparison op, so we match everything.
+        match = true;
+        break;
+      default:
+        NS_WARNING("Bogus op in GfxDriverInfo");
+        break;
+    }
+#else
+    // We don't care what driver version it was. We only check OS version and if
+    // the device matches.
+    match = true;
+#endif
+
+    if (match || info[i].mDriverVersion == GfxDriverInfo::allDriverVersions) {
+      if (info[i].mFeature == GfxDriverInfo::allFeatures ||
+          info[i].mFeature == aFeature ||
+          (info[i].mFeature == GfxDriverInfo::optionalFeatures &&
+           OnlyAllowFeatureOnKnownConfig(aFeature))) {
+        status = info[i].mFeatureStatus;
+        if (!info[i].mRuleId.IsEmpty()) {
+          aFailureId = info[i].mRuleId.get();
+        } else {
+          aFailureId = "FEATURE_FAILURE_DL_BLOCKLIST_NO_ID";
+        }
+        break;
+      }
+    }
+  }
+
+#if defined(XP_WIN)
+  // As a very special case, we block D2D on machines with an NVidia 310M GPU
+  // as either the primary or secondary adapter.  D2D is also blocked when the
+  // NV 310M is the primary adapter (using the standard blocklisting mechanism).
+  // If the primary GPU already matched something in the blocklist then we
+  // ignore this special rule.  See bug 1008759.
+  if (status == nsIGfxInfo::FEATURE_STATUS_UNKNOWN &&
+      (aFeature == nsIGfxInfo::FEATURE_DIRECT2D)) {
+    if (!adapterInfoFailed[1]) {
+      nsAString& nvVendorID =
+          (nsAString&)GfxDriverInfo::GetDeviceVendor(DeviceVendor::NVIDIA);
+      const nsString nv310mDeviceId = u"0x0A70"_ns;
+      if (nvVendorID.Equals(adapterVendorID[1],
+                            nsCaseInsensitiveStringComparator) &&
+          nv310mDeviceId.Equals(adapterDeviceID[1],
+                                nsCaseInsensitiveStringComparator)) {
+        status = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_D2D_NV310M_BLOCK";
+      }
+    }
+  }
+
+  // Depends on Windows driver versioning. We don't pass a GfxDriverInfo object
+  // back to the Windows handler, so we must handle this here.
+  if (status == FEATURE_BLOCKED_DRIVER_VERSION) {
+    if (info[i].mSuggestedVersion) {
+      aSuggestedVersion.AppendPrintf("%s", info[i].mSuggestedVersion);
+    } else if (info[i].mComparisonOp == DRIVER_LESS_THAN &&
+               info[i].mDriverVersion != GfxDriverInfo::allDriverVersions) {
+      aSuggestedVersion.AppendPrintf(
+          "%lld.%lld.%lld.%lld",
+          (info[i].mDriverVersion & 0xffff000000000000) >> 48,
+          (info[i].mDriverVersion & 0x0000ffff00000000) >> 32,
+          (info[i].mDriverVersion & 0x00000000ffff0000) >> 16,
+          (info[i].mDriverVersion & 0x000000000000ffff));
+    }
+  }
+#endif
+
+  return status;
+}
+
+void GfxInfoBase::SetFeatureStatus(nsTArray<gfx::GfxInfoFeatureStatus>&& aFS) {
+  MOZ_ASSERT(!sFeatureStatus);
+  InitFeatureStatus(new nsTArray<gfx::GfxInfoFeatureStatus>(std::move(aFS)));
+}
+
+bool GfxInfoBase::DoesWindowProtocolMatch(
+    const nsAString& aBlocklistWindowProtocol,
+    const nsAString& aWindowProtocol) {
+  return aBlocklistWindowProtocol.Equals(aWindowProtocol,
+                                         nsCaseInsensitiveStringComparator) ||
+         aBlocklistWindowProtocol.Equals(
+             GfxDriverInfo::GetWindowProtocol(WindowProtocol::All),
+             nsCaseInsensitiveStringComparator);
+}
+
+bool GfxInfoBase::DoesVendorMatch(const nsAString& aBlocklistVendor,
+                                  const nsAString& aAdapterVendor) {
+  return aBlocklistVendor.Equals(aAdapterVendor,
+                                 nsCaseInsensitiveStringComparator) ||
+         aBlocklistVendor.Equals(
+             GfxDriverInfo::GetDeviceVendor(DeviceVendor::All),
+             nsCaseInsensitiveStringComparator);
+}
+
+bool GfxInfoBase::DoesDriverVendorMatch(const nsAString& aBlocklistVendor,
+                                        const nsAString& aDriverVendor) {
+  return aBlocklistVendor.Equals(aDriverVendor,
+                                 nsCaseInsensitiveStringComparator) ||
+         aBlocklistVendor.Equals(
+             GfxDriverInfo::GetDriverVendor(DriverVendor::All),
+             nsCaseInsensitiveStringComparator);
+}
+
+bool GfxInfoBase::IsFeatureAllowlisted(int32_t aFeature) const {
+  return aFeature == nsIGfxInfo::FEATURE_VIDEO_OVERLAY ||
+         aFeature == nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY;
+}
+
+nsresult GfxInfoBase::GetFeatureStatusImpl(
+    int32_t aFeature, int32_t* aStatus, nsAString& aSuggestedVersion,
+    const nsTArray<GfxDriverInfo>& aDriverInfo, nsACString& aFailureId,
+    OperatingSystem* aOS /* = nullptr */) {
+  if (aFeature <= 0) {
+    gfxWarning() << "Invalid feature <= 0";
+    return NS_OK;
+  }
+
+  if (*aStatus != nsIGfxInfo::FEATURE_STATUS_UNKNOWN) {
+    // Terminate now with the status determined by the derived type (OS-specific
+    // code).
+    return NS_OK;
+  }
+
+  if (sShutdownOccurred) {
+    // This is futile; we've already commenced shutdown and our blocklists have
+    // been deleted. We may want to look into resurrecting the blocklist instead
+    // but for now, just don't even go there.
+    return NS_OK;
+  }
+
+  // Ensure any additional initialization required is complete.
+  GetData();
+
+  // If an operating system was provided by the derived GetFeatureStatusImpl,
+  // grab it here. Otherwise, the OS is unknown.
+  OperatingSystem os = (aOS ? *aOS : OperatingSystem::Unknown);
+
+  nsAutoString adapterVendorID;
+  nsAutoString adapterDeviceID;
+  nsAutoString adapterDriverVersionString;
+  if (NS_FAILED(GetAdapterVendorID(adapterVendorID)) ||
+      NS_FAILED(GetAdapterDeviceID(adapterDeviceID)) ||
+      NS_FAILED(GetAdapterDriverVersion(adapterDriverVersionString))) {
+    if (OnlyAllowFeatureOnKnownConfig(aFeature)) {
+      aFailureId = "FEATURE_FAILURE_CANT_RESOLVE_ADAPTER";
+      *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+    } else {
+      *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+    }
+    return NS_OK;
+  }
+
+  // We only check either the given blocklist, or the static list, as given.
+  int32_t status;
+  if (aDriverInfo.Length()) {
+    status =
+        FindBlocklistedDeviceInList(aDriverInfo, aSuggestedVersion, aFeature,
+                                    aFailureId, os, /* aForAllowing */ false);
+  } else {
+    if (!sDriverInfo) {
+      sDriverInfo = new nsTArray<GfxDriverInfo>();
+    }
+    status = FindBlocklistedDeviceInList(GetGfxDriverInfo(), aSuggestedVersion,
+                                         aFeature, aFailureId, os,
+                                         /* aForAllowing */ false);
+  }
+
+  if (status == nsIGfxInfo::FEATURE_STATUS_UNKNOWN) {
+    if (IsFeatureAllowlisted(aFeature)) {
+      // This feature is actually using the allowlist; that means after we pass
+      // the blocklist to prevent us explicitly from getting the feature, we now
+      // need to check the allowlist to ensure we are allowed to get it in the
+      // first place.
+      if (aDriverInfo.Length()) {
+        status = FindBlocklistedDeviceInList(aDriverInfo, aSuggestedVersion,
+                                             aFeature, aFailureId, os,
+                                             /* aForAllowing */ true);
+      } else {
+        status = FindBlocklistedDeviceInList(
+            GetGfxDriverInfo(), aSuggestedVersion, aFeature, aFailureId, os,
+            /* aForAllowing */ true);
+      }
+
+      if (status == nsIGfxInfo::FEATURE_STATUS_UNKNOWN) {
+        status = nsIGfxInfo::FEATURE_DENIED;
+      }
+    } else {
+      // It's now done being processed. It's safe to set the status to
+      // STATUS_OK.
+      status = nsIGfxInfo::FEATURE_STATUS_OK;
+    }
+  }
+
+  *aStatus = status;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetFeatureSuggestedDriverVersion(int32_t aFeature,
+                                              nsAString& aVersion) {
+  nsCString version;
+  if (GetPrefValueForDriverVersion(version)) {
+    aVersion = NS_ConvertASCIItoUTF16(version);
+    return NS_OK;
+  }
+
+  int32_t status;
+  nsCString discardFailureId;
+  nsTArray<GfxDriverInfo> driverInfo;
+  return GetFeatureStatusImpl(aFeature, &status, aVersion, driverInfo,
+                              discardFailureId);
+}
+
+void GfxInfoBase::EvaluateDownloadedBlocklist(
+    nsTArray<GfxDriverInfo>& aDriverInfo) {
+  // If the list is empty, then we don't actually want to call
+  // GetFeatureStatusImpl since we will use the static list instead. In that
+  // case, all we want to do is make sure the pref is removed.
+  if (aDriverInfo.IsEmpty()) {
+    gfxCriticalNoteOnce << "Evaluate empty downloaded blocklist";
+    return;
+  }
+
+  OperatingSystem os = GetOperatingSystem();
+
+  // For every feature we know about, we evaluate whether this blocklist has a
+  // non-STATUS_OK status. If it does, we set the pref we evaluate in
+  // GetFeatureStatus above, so we don't need to hold on to this blocklist
+  // anywhere permanent.
+  for (int feature = 1; feature <= nsIGfxInfo::FEATURE_MAX_VALUE; ++feature) {
+    int32_t status = nsIGfxInfo::FEATURE_STATUS_UNKNOWN;
+    nsCString failureId;
+    nsAutoString suggestedVersion;
+
+    // Note that we are careful to call the base class method since we only want
+    // to evaluate the downloadable blocklist for these prefs.
+    MOZ_ALWAYS_TRUE(NS_SUCCEEDED(GfxInfoBase::GetFeatureStatusImpl(
+        feature, &status, suggestedVersion, aDriverInfo, failureId, &os)));
+
+    switch (status) {
+      default:
+        MOZ_FALLTHROUGH_ASSERT("Unhandled feature status!");
+      case nsIGfxInfo::FEATURE_STATUS_UNKNOWN:
+        // This may be returned during shutdown or for invalid features.
+      case nsIGfxInfo::FEATURE_ALLOW_ALWAYS:
+      case nsIGfxInfo::FEATURE_ALLOW_QUALIFIED:
+      case nsIGfxInfo::FEATURE_DENIED:
+        // We cannot use the downloadable blocklist to control the allowlist.
+        // If a feature is allowlisted, then we should also ignore DENIED
+        // statuses from GetFeatureStatusImpl because we don't check the
+        // static list when and this is an expected value. If we wish to
+        // override the allowlist, it is as simple as creating a normal
+        // blocklist rule with a BLOCKED* status code.
+      case nsIGfxInfo::FEATURE_STATUS_OK:
+        RemovePrefForFeature(feature);
+        break;
+
+      case nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION:
+        if (!suggestedVersion.IsEmpty()) {
+          SetPrefValueForDriverVersion(suggestedVersion);
+        } else {
+          RemovePrefForDriverVersion();
+        }
+        [[fallthrough]];
+
+      case nsIGfxInfo::FEATURE_BLOCKED_MISMATCHED_VERSION:
+      case nsIGfxInfo::FEATURE_BLOCKED_DEVICE:
+      case nsIGfxInfo::FEATURE_DISCOURAGED:
+      case nsIGfxInfo::FEATURE_BLOCKED_OS_VERSION:
+      case nsIGfxInfo::FEATURE_BLOCKED_PLATFORM_TEST:
+        SetPrefValueForFeature(feature, status, failureId);
+        break;
+    }
+  }
+}
+
+NS_IMETHODIMP_(void)
+GfxInfoBase::LogFailure(const nsACString& failure) {
+  // gfxCriticalError has a mutex lock of its own, so we may not actually
+  // need this lock. ::GetFailures() accesses the data but the LogForwarder
+  // will not return the copy of the logs unless it can get the same lock
+  // that gfxCriticalError uses.  Still, that is so much of an implementation
+  // detail that it's nicer to just add an extra lock here and in
+  // ::GetFailures()
+  MutexAutoLock lock(mMutex);
+
+  // By default, gfxCriticalError asserts; make it not assert in this case.
+  gfxCriticalError(CriticalLog::DefaultOptions(false))
+      << "(LF) " << failure.BeginReading();
+}
+
+NS_IMETHODIMP GfxInfoBase::GetFailures(nsTArray<int32_t>& indices,
+                                       nsTArray<nsCString>& failures) {
+  MutexAutoLock lock(mMutex);
+
+  LogForwarder* logForwarder = Factory::GetLogForwarder();
+  if (!logForwarder) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  // There are two string copies in this method, starting with this one. We are
+  // assuming this is not a big deal, as the size of the array should be small
+  // and the strings in it should be small as well (the error messages in the
+  // code.)  The second copy happens with the AppendElement() calls.
+  // Technically, we don't need the mutex lock after the StringVectorCopy()
+  // call.
+  LoggingRecord loggedStrings = logForwarder->LoggingRecordCopy();
+  LoggingRecord::const_iterator it;
+  for (it = loggedStrings.begin(); it != loggedStrings.end(); ++it) {
+    failures.AppendElement(nsDependentCSubstring(std::get<1>(*it).c_str(),
+                                                 std::get<1>(*it).size()));
+    indices.AppendElement(std::get<0>(*it));
+  }
+
+  return NS_OK;
+}
+
+nsTArray<GfxInfoCollectorBase*>* sCollectors;
+
+static void InitCollectors() {
+  if (!sCollectors) sCollectors = new nsTArray<GfxInfoCollectorBase*>;
+}
+
+nsresult GfxInfoBase::GetInfo(JSContext* aCx,
+                              JS::MutableHandle<JS::Value> aResult) {
+  InitCollectors();
+  InfoObject obj(aCx);
+
+  for (uint32_t i = 0; i < sCollectors->Length(); i++) {
+    (*sCollectors)[i]->GetInfo(obj);
+  }
+
+  // Some example property definitions
+  // obj.DefineProperty("wordCacheSize", gfxTextRunWordCache::Count());
+  // obj.DefineProperty("renderer", mRendererIDsString);
+  // obj.DefineProperty("five", 5);
+
+  if (!obj.mOk) {
+    return NS_ERROR_FAILURE;
+  }
+
+  aResult.setObject(*obj.mObj);
+  return NS_OK;
+}
+
+nsAutoCString gBaseAppVersion;
+
+const nsCString& GfxInfoBase::GetApplicationVersion() {
+  static bool versionInitialized = false;
+  if (!versionInitialized) {
+    // If we fail to get the version, we will not try again.
+    versionInitialized = true;
+
+    // Get the version from xpcom/system/nsIXULAppInfo.idl
+    nsCOMPtr<nsIXULAppInfo> app = do_GetService("@mozilla.org/xre/app-info;1");
+    if (app) {
+      app->GetVersion(gBaseAppVersion);
+    }
+  }
+  return gBaseAppVersion;
+}
+
+/* static */ bool GfxInfoBase::OnlyAllowFeatureOnKnownConfig(int32_t aFeature) {
+  switch (aFeature) {
+    // The GPU process doesn't need hardware acceleration and can run on
+    // devices that we normally block from not being on our whitelist.
+    case nsIGfxInfo::FEATURE_GPU_PROCESS:
+      return kIsAndroid;
+    // We can mostly assume that ANGLE will work
+    case nsIGfxInfo::FEATURE_DIRECT3D_11_ANGLE:
+    // Remote WebGL is needed for Win32k Lockdown, so it should be enabled
+    // regardless of HW support or not
+    case nsIGfxInfo::FEATURE_ALLOW_WEBGL_OUT_OF_PROCESS:
+    // Backdrop filter should generally work, especially if we fall back to
+    // Software WebRender because of an unknown vendor.
+    case nsIGfxInfo::FEATURE_BACKDROP_FILTER:
+      return false;
+    default:
+      return true;
+  }
+}
+
+void GfxInfoBase::AddCollector(GfxInfoCollectorBase* collector) {
+  InitCollectors();
+  sCollectors->AppendElement(collector);
+}
+
+void GfxInfoBase::RemoveCollector(GfxInfoCollectorBase* collector) {
+  InitCollectors();
+  for (uint32_t i = 0; i < sCollectors->Length(); i++) {
+    if ((*sCollectors)[i] == collector) {
+      sCollectors->RemoveElementAt(i);
+      break;
+    }
+  }
+  if (sCollectors->IsEmpty()) {
+    delete sCollectors;
+    sCollectors = nullptr;
+  }
+}
+
+static void AppendMonitor(JSContext* aCx, widget::Screen& aScreen,
+                          JS::Handle<JSObject*> aOutArray, int32_t aIndex) {
+  JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+
+  auto screenSize = aScreen.GetRect().Size();
+
+  JS::Rooted<JS::Value> screenWidth(aCx, JS::Int32Value(screenSize.width));
+  JS_SetProperty(aCx, obj, "screenWidth", screenWidth);
+
+  JS::Rooted<JS::Value> screenHeight(aCx, JS::Int32Value(screenSize.height));
+  JS_SetProperty(aCx, obj, "screenHeight", screenHeight);
+
+  // XXX Just preserving behavior since this is exposed to telemetry, but we
+  // could consider including this everywhere.
+#ifdef XP_MACOSX
+  JS::Rooted<JS::Value> scale(
+      aCx, JS::NumberValue(aScreen.GetContentsScaleFactor()));
+  JS_SetProperty(aCx, obj, "scale", scale);
+#endif
+
+#ifdef XP_WIN
+  JS::Rooted<JS::Value> refreshRate(aCx,
+                                    JS::Int32Value(aScreen.GetRefreshRate()));
+  JS_SetProperty(aCx, obj, "refreshRate", refreshRate);
+
+  JS::Rooted<JS::Value> pseudoDisplay(
+      aCx, JS::BooleanValue(aScreen.GetIsPseudoDisplay()));
+  JS_SetProperty(aCx, obj, "pseudoDisplay", pseudoDisplay);
+#endif
+
+  JS::Rooted<JS::Value> element(aCx, JS::ObjectValue(*obj));
+  JS_SetElement(aCx, aOutArray, aIndex, element);
+}
+
+nsresult GfxInfoBase::FindMonitors(JSContext* aCx,
+                                   JS::Handle<JSObject*> aOutArray) {
+  int32_t index = 0;
+  auto& sm = ScreenManager::GetSingleton();
+  for (auto& screen : sm.CurrentScreenList()) {
+    AppendMonitor(aCx, *screen, aOutArray, index++);
+  }
+
+  if (index == 0) {
+    // Ensure we return at least one monitor, this is needed for xpcshell.
+    RefPtr<Screen> screen = sm.GetPrimaryScreen();
+    AppendMonitor(aCx, *screen, aOutArray, index++);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetMonitors(JSContext* aCx, JS::MutableHandle<JS::Value> aResult) {
+  JS::Rooted<JSObject*> array(aCx, JS::NewArrayObject(aCx, 0));
+
+  nsresult rv = FindMonitors(aCx, array);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  aResult.setObject(*array);
+  return NS_OK;
+}
+
+static inline bool SetJSPropertyString(JSContext* aCx,
+                                       JS::Handle<JSObject*> aObj,
+                                       const char* aProp, const char* aString) {
+  JS::Rooted<JSString*> str(aCx, JS_NewStringCopyZ(aCx, aString));
+  if (!str) {
+    return false;
+  }
+
+  JS::Rooted<JS::Value> val(aCx, JS::StringValue(str));
+  return JS_SetProperty(aCx, aObj, aProp, val);
+}
+
+template <typename T>
+static inline bool AppendJSElement(JSContext* aCx, JS::Handle<JSObject*> aObj,
+                                   const T& aValue) {
+  uint32_t index;
+  if (!JS::GetArrayLength(aCx, aObj, &index)) {
+    return false;
+  }
+  return JS_SetElement(aCx, aObj, index, aValue);
+}
+
+nsresult GfxInfoBase::GetFeatures(JSContext* aCx,
+                                  JS::MutableHandle<JS::Value> aOut) {
+  JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+  if (!obj) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  aOut.setObject(*obj);
+
+  layers::LayersBackend backend =
+      gfxPlatform::Initialized()
+          ? gfxPlatform::GetPlatform()->GetCompositorBackend()
+          : layers::LayersBackend::LAYERS_NONE;
+  const char* backendName = layers::GetLayersBackendName(backend);
+  SetJSPropertyString(aCx, obj, "compositor", backendName);
+
+  // If graphics isn't initialized yet, just stop now.
+  if (!gfxPlatform::Initialized()) {
+    return NS_OK;
+  }
+
+  DescribeFeatures(aCx, obj);
+  return NS_OK;
+}
+
+nsresult GfxInfoBase::GetFeatureLog(JSContext* aCx,
+                                    JS::MutableHandle<JS::Value> aOut) {
+  JS::Rooted<JSObject*> containerObj(aCx, JS_NewPlainObject(aCx));
+  if (!containerObj) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  aOut.setObject(*containerObj);
+
+  JS::Rooted<JSObject*> featureArray(aCx, JS::NewArrayObject(aCx, 0));
+  if (!featureArray) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  // Collect features.
+  gfxConfig::ForEachFeature([&](const char* aName, const char* aDescription,
+                                FeatureState& aFeature) -> void {
+    JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+    if (!obj) {
+      return;
+    }
+    if (!SetJSPropertyString(aCx, obj, "name", aName) ||
+        !SetJSPropertyString(aCx, obj, "description", aDescription) ||
+        !SetJSPropertyString(aCx, obj, "status",
+                             FeatureStatusToString(aFeature.GetValue()))) {
+      return;
+    }
+
+    JS::Rooted<JS::Value> log(aCx);
+    if (!BuildFeatureStateLog(aCx, aFeature, &log)) {
+      return;
+    }
+    if (!JS_SetProperty(aCx, obj, "log", log)) {
+      return;
+    }
+
+    if (!AppendJSElement(aCx, featureArray, obj)) {
+      return;
+    }
+  });
+
+  JS::Rooted<JSObject*> fallbackArray(aCx, JS::NewArrayObject(aCx, 0));
+  if (!fallbackArray) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  // Collect fallbacks.
+  gfxConfig::ForEachFallback(
+      [&](const char* aName, const char* aMessage) -> void {
+        JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+        if (!obj) {
+          return;
+        }
+
+        if (!SetJSPropertyString(aCx, obj, "name", aName) ||
+            !SetJSPropertyString(aCx, obj, "message", aMessage)) {
+          return;
+        }
+
+        if (!AppendJSElement(aCx, fallbackArray, obj)) {
+          return;
+        }
+      });
+
+  JS::Rooted<JS::Value> val(aCx);
+
+  val = JS::ObjectValue(*featureArray);
+  JS_SetProperty(aCx, containerObj, "features", val);
+
+  val = JS::ObjectValue(*fallbackArray);
+  JS_SetProperty(aCx, containerObj, "fallbacks", val);
+
+  return NS_OK;
+}
+
+bool GfxInfoBase::BuildFeatureStateLog(JSContext* aCx,
+                                       const FeatureState& aFeature,
+                                       JS::MutableHandle<JS::Value> aOut) {
+  JS::Rooted<JSObject*> log(aCx, JS::NewArrayObject(aCx, 0));
+  if (!log) {
+    return false;
+  }
+  aOut.setObject(*log);
+
+  aFeature.ForEachStatusChange([&](const char* aType, FeatureStatus aStatus,
+                                   const char* aMessage,
+                                   const nsCString& aFailureId) -> void {
+    JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+    if (!obj) {
+      return;
+    }
+
+    if (!SetJSPropertyString(aCx, obj, "type", aType) ||
+        !SetJSPropertyString(aCx, obj, "status",
+                             FeatureStatusToString(aStatus)) ||
+        (!aFailureId.IsEmpty() &&
+         !SetJSPropertyString(aCx, obj, "failureId", aFailureId.get())) ||
+        (aMessage && !SetJSPropertyString(aCx, obj, "message", aMessage))) {
+      return;
+    }
+
+    if (!AppendJSElement(aCx, log, obj)) {
+      return;
+    }
+  });
+
+  return true;
+}
+
+void GfxInfoBase::DescribeFeatures(JSContext* aCx, JS::Handle<JSObject*> aObj) {
+  JS::Rooted<JSObject*> obj(aCx);
+
+  gfx::FeatureState& hwCompositing =
+      gfxConfig::GetFeature(gfx::Feature::HW_COMPOSITING);
+  InitFeatureObject(aCx, aObj, "hwCompositing", hwCompositing, &obj);
+
+  gfx::FeatureState& gpuProcess =
+      gfxConfig::GetFeature(gfx::Feature::GPU_PROCESS);
+  InitFeatureObject(aCx, aObj, "gpuProcess", gpuProcess, &obj);
+
+  gfx::FeatureState& webrender = gfxConfig::GetFeature(gfx::Feature::WEBRENDER);
+  InitFeatureObject(aCx, aObj, "webrender", webrender, &obj);
+
+  gfx::FeatureState& wrCompositor =
+      gfxConfig::GetFeature(gfx::Feature::WEBRENDER_COMPOSITOR);
+  InitFeatureObject(aCx, aObj, "wrCompositor", wrCompositor, &obj);
+
+  gfx::FeatureState& openglCompositing =
+      gfxConfig::GetFeature(gfx::Feature::OPENGL_COMPOSITING);
+  InitFeatureObject(aCx, aObj, "openglCompositing", openglCompositing, &obj);
+
+  gfx::FeatureState& omtp = gfxConfig::GetFeature(gfx::Feature::OMTP);
+  InitFeatureObject(aCx, aObj, "omtp", omtp, &obj);
+}
+
+bool GfxInfoBase::InitFeatureObject(JSContext* aCx,
+                                    JS::Handle<JSObject*> aContainer,
+                                    const char* aName,
+                                    mozilla::gfx::FeatureState& aFeatureState,
+                                    JS::MutableHandle<JSObject*> aOutObj) {
+  JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+  if (!obj) {
+    return false;
+  }
+
+  nsCString status = aFeatureState.GetStatusAndFailureIdString();
+
+  JS::Rooted<JSString*> str(aCx, JS_NewStringCopyZ(aCx, status.get()));
+  JS::Rooted<JS::Value> val(aCx, JS::StringValue(str));
+  JS_SetProperty(aCx, obj, "status", val);
+
+  // Add the feature object to the container.
+  {
+    JS::Rooted<JS::Value> val(aCx, JS::ObjectValue(*obj));
+    JS_SetProperty(aCx, aContainer, aName, val);
+  }
+
+  aOutObj.set(obj);
+  return true;
+}
+
+nsresult GfxInfoBase::GetActiveCrashGuards(JSContext* aCx,
+                                           JS::MutableHandle<JS::Value> aOut) {
+  JS::Rooted<JSObject*> array(aCx, JS::NewArrayObject(aCx, 0));
+  if (!array) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  aOut.setObject(*array);
+
+  DriverCrashGuard::ForEachActiveCrashGuard(
+      [&](const char* aName, const char* aPrefName) -> void {
+        JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+        if (!obj) {
+          return;
+        }
+        if (!SetJSPropertyString(aCx, obj, "type", aName)) {
+          return;
+        }
+        if (!SetJSPropertyString(aCx, obj, "prefName", aPrefName)) {
+          return;
+        }
+        if (!AppendJSElement(aCx, array, obj)) {
+          return;
+        }
+      });
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetTargetFrameRate(uint32_t* aTargetFrameRate) {
+  *aTargetFrameRate = gfxPlatform::TargetFrameRate();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetCodecSupportInfo(nsACString& aCodecSupportInfo) {
+  aCodecSupportInfo.Assign(gfx::gfxVars::CodecSupportInfo());
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetIsHeadless(bool* aIsHeadless) {
+  *aIsHeadless = gfxPlatform::IsHeadless();
+  return NS_OK;
+}
+
+#if defined(MOZ_WIDGET_ANDROID)
+
+const char* chromebookProductList[] = {
+    "asuka",    "asurada",   "atlas",    "auron",    "banjo",     "banon",
+    "bob",      "brask",     "brya",     "buddy",    "butterfly", "candy",
+    "caroline", "cave",      "celes",    "chell",    "cherry",    "clapper",
+    "coral",    "corsola",   "cyan",     "daisy",    "dedede",    "drallion",
+    "edgar",    "elm",       "enguarde", "eve",      "expresso",  "falco",
+    "fizz",     "gandof",    "glimmer",  "gnawty",   "grunt",     "guado",
+    "guybrush", "hana",      "hatch",    "heli",     "jacuzzi",   "kalista",
+    "kefka",    "kevin",     "kip",      "kukui",    "lars",      "leon",
+    "link",     "lulu",      "lumpy",    "mccloud",  "monroe",    "nami",
+    "nautilus", "ninja",     "nissa",    "nocturne", "nyan",      "octopus",
+    "orco",     "panther",   "parrot",   "peach",    "peppy",     "puff",
+    "pyro",     "quawks",    "rammus",   "reef",     "reks",      "relm",
+    "rikku",    "samus",     "sand",     "sarien",   "scarlet",   "sentry",
+    "setzer",   "skyrim",    "snappy",   "soraka",   "squawks",   "staryu",
+    "stout",    "strongbad", "stumpy",   "sumo",     "swanky",    "terra",
+    "tidus",    "tricky",    "trogdor",  "ultima",   "veyron",    "volteer",
+    "winky",    "wizpig",    "wolf",     "x86",      "zako",      "zork"};
+
+bool ProductIsChromebook(nsCString product) {
+  size_t result;
+  return BinarySearchIf(
+      chromebookProductList, 0, ArrayLength(chromebookProductList),
+      [&](const char* const aValue) -> int {
+        return strcmp(product.get(), aValue);
+      },
+      &result);
+}
+#endif
+
+using Device = nsIGfxInfo::FontVisibilityDeviceDetermination;
+static StaticAutoPtr<std::pair<Device, nsString>> ret;
+
+std::pair<Device, nsString>* GfxInfoBase::GetFontVisibilityDeterminationPair() {
+  if(!ret) {
+    ret = new std::pair<Device, nsString>();
+    ret->first = Device::Unassigned;
+    ret->second = u""_ns;
+    ClearOnShutdown(&ret);
+  }
+
+  if (ret->first != Device::Unassigned) {
+    return ret;
+  }
+
+#if defined(MOZ_WIDGET_ANDROID)
+  auto androidReleaseVersion = strtol(
+      java::sdk::Build::VERSION::RELEASE()->ToCString().get(), nullptr, 10);
+
+  auto androidManufacturer = java::sdk::Build::MANUFACTURER()->ToCString();
+  nsContentUtils::ASCIIToLower(androidManufacturer);
+
+  auto androidBrand = java::sdk::Build::BRAND()->ToCString();
+  nsContentUtils::ASCIIToLower(androidBrand);
+
+  auto androidModel = java::sdk::Build::MODEL()->ToCString();
+  nsContentUtils::ASCIIToLower(androidModel);
+
+  auto androidProduct = java::sdk::Build::PRODUCT()->ToCString();
+  nsContentUtils::ASCIIToLower(androidProduct);
+
+  auto androidProductIsChromebook = ProductIsChromebook(androidProduct);
+
+  if (androidReleaseVersion < 4 || androidReleaseVersion > 20) {
+    // Something is screwy, oh well.
+    ret->second.AppendASCII("Unknown Release Version - ");
+    ret->first = Device::Android_Unknown_Release_Version;
+  } else if (androidReleaseVersion <= 8) {
+    ret->second.AppendASCII("Android <9 - ");
+    ret->first = Device::Android_sub_9;
+  } else if (androidReleaseVersion <= 11) {
+    ret->second.AppendASCII("Android 9-11 - ");
+    ret->first = Device::Android_9_11;
+  } else if (androidReleaseVersion > 11) {
+    ret->second.AppendASCII("Android 12+ - ");
+    ret->first = Device::Android_12_plus;
+  } else {
+    MOZ_CRASH_UNSAFE_PRINTF(
+        "Somehow wound up in GetFontVisibilityDeterminationPair with a release "
+        "version of %li",
+        androidReleaseVersion);
+  }
+
+  if (androidManufacturer == "google" && androidModel == androidProduct &&
+      androidProductIsChromebook) {
+    // Chromebook font set coming later
+    ret->second.AppendASCII("Chromebook - ");
+    ret->first = Device::Android_Chromebook;
+  }
+  if (androidBrand == "amazon") {
+    // Amazon Fire font set coming later
+    ret->second.AppendASCII("Amazon - ");
+    ret->first = Device::Android_Amazon;
+  }
+  if (androidBrand == "peloton") {
+    // We don't know how to categorize fonts on this system
+    ret->second.AppendASCII("Peloton - ");
+    ret->first = Device::Android_Unknown_Peloton;
+  }
+  if (androidProduct == "vbox86p") {
+    ret->second.AppendASCII("vbox - ");
+    // We can't categorize fonts when running in an emulator on a Desktop
+    ret->first = Device::Android_Unknown_vbox;
+  }
+  if (androidModel.Find("mitv"_ns) != kNotFound && androidBrand == "xiaomi") {
+    // We don't know how to categorize fonts on this system
+    ret->second.AppendASCII("mitv - ");
+    ret->first = Device::Android_Unknown_mitv;
+  }
+
+  ret->second.AppendPrintf(
+      "release_version_str=%s, release_version=%li",
+      java::sdk::Build::VERSION::RELEASE()->ToCString().get(),
+      androidReleaseVersion);
+  ret->second.AppendPrintf(
+      ", manufacturer=%s, brand=%s, model=%s, product=%s, chromebook=%s",
+      androidManufacturer.get(), androidBrand.get(), androidModel.get(),
+      androidProduct.get(), androidProductIsChromebook ? "yes" : "no");
+
+#elif defined(XP_LINUX)
+  ret->first = Device::Linux_Unknown;
+
+  long versionMajor = 0;
+  FILE* fp = fopen("/etc/os-release", "r");
+  if (fp) {
+    char buf[512];
+    while (fgets(buf, sizeof(buf), fp)) {
+      if (strncmp(buf, "VERSION_ID=\"", 12) == 0) {
+        ret->second.AppendPrintf("VERSION_ID=%.11s", buf + 11);
+        versionMajor = strtol(buf + 12, nullptr, 10);
+        if (ret->first != Device::Linux_Unknown) {
+          break;
+        }
+      }
+
+      if (strncmp(buf, "ID=", 3) == 0) {
+        ret->second.AppendPrintf("ID=%.6s", buf + 3);
+        if (strncmp(buf + 3, "ubuntu", 6) == 0) {
+          ret->first = Device::Linux_Ubuntu_any;
+        } else if (strncmp(buf + 3, "fedora", 6) == 0) {
+          ret->first = Device::Linux_Fedora_any;
+        }
+
+        if (versionMajor) {
+          break;
+        }
+      }
+    }
+    fclose(fp);
+  }
+  if (ret->first == Device::Linux_Ubuntu_any) {
+    if (versionMajor == 20) {
+      ret->first = Device::Linux_Ubuntu_20;
+      ret->second.Insert(u"Ubuntu 20 - ", 0);
+    } else if (versionMajor == 22) {
+      ret->first = Device::Linux_Ubuntu_22;
+      ret->second.Insert(u"Ubuntu 22 - ", 0);
+    } else {
+      ret->second.Insert(u"Ubuntu Unknown - ", 0);
+    }
+  } else if (ret->first == Device::Linux_Fedora_any) {
+    if (versionMajor == 38) {
+      ret->first = Device::Linux_Fedora_38;
+      ret->second.Insert(u"Fedora 38 - ", 0);
+    } else if (versionMajor == 39) {
+      ret->first = Device::Linux_Fedora_39;
+      ret->second.Insert(u"Fedora 39 - ", 0);
+    } else {
+      ret->second.Insert(u"Fedora Unknown - ", 0);
+    }
+  } else {
+    ret->second.Insert(u"Linux Unknown - ", 0);
+  }
+
+#elif defined(XP_MACOSX)
+  ret->first = Device::MacOS_Platform;
+  ret->second.AppendASCII("macOS Platform");
+#elif defined(XP_WIN)
+  ret->first = Device::Windows_Platform;
+  ret->second.AppendASCII("Windows Platform");
+#else
+  ret->first = Device::Unknown_Platform;
+  ret->second.AppendASCII("Unknown Platform");
+#endif
+
+  return ret;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetFontVisibilityDetermination(
+    Device* aFontVisibilityDetermination) {
+  auto ret = GetFontVisibilityDeterminationPair();
+
+  *aFontVisibilityDetermination = ret->first;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetFontVisibilityDeterminationStr(
+    nsAString& aFontVisibilityDeterminationStr) {
+  auto ret = GetFontVisibilityDeterminationPair();
+  aFontVisibilityDeterminationStr.Assign(ret->second);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetContentBackend(nsAString& aContentBackend) {
+  BackendType backend = gfxPlatform::GetPlatform()->GetDefaultContentBackend();
+  nsString outStr;
+
+  switch (backend) {
+    case BackendType::DIRECT2D1_1: {
+      outStr.AppendPrintf("Direct2D 1.1");
+      break;
+    }
+    case BackendType::SKIA: {
+      outStr.AppendPrintf("Skia");
+      break;
+    }
+    case BackendType::CAIRO: {
+      outStr.AppendPrintf("Cairo");
+      break;
+    }
+    default:
+      return NS_ERROR_FAILURE;
+  }
+
+  aContentBackend.Assign(outStr);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetAzureCanvasBackend(nsAString& aBackend) {
+  CopyASCIItoUTF16(mozilla::MakeStringSpan(
+                       gfxPlatform::GetPlatform()->GetAzureCanvasBackend()),
+                   aBackend);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetAzureContentBackend(nsAString& aBackend) {
+  CopyASCIItoUTF16(mozilla::MakeStringSpan(
+                       gfxPlatform::GetPlatform()->GetAzureContentBackend()),
+                   aBackend);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::GetUsingGPUProcess(bool* aOutValue) {
+  GPUProcessManager* gpu = GPUProcessManager::Get();
+  if (!gpu) {
+    // Not supported in content processes.
+    return NS_ERROR_FAILURE;
+  }
+
+  *aOutValue = !!gpu->GetGPUChild();
+  return NS_OK;
+}
+
+NS_IMETHODIMP_(int32_t)
+GfxInfoBase::GetMaxRefreshRate(bool* aMixed) {
+  if (aMixed) {
+    *aMixed = false;
+  }
+
+  int32_t maxRefreshRate = 0;
+  for (auto& screen : ScreenManager::GetSingleton().CurrentScreenList()) {
+    int32_t refreshRate = screen->GetRefreshRate();
+    if (aMixed && maxRefreshRate > 0 && maxRefreshRate != refreshRate) {
+      *aMixed = true;
+    }
+    maxRefreshRate = std::max(maxRefreshRate, refreshRate);
+  }
+
+  return maxRefreshRate > 0 ? maxRefreshRate : -1;
+}
+
+NS_IMETHODIMP
+GfxInfoBase::ControlGPUProcessForXPCShell(bool aEnable, bool* _retval) {
+  gfxPlatform::GetPlatform();
+
+  GPUProcessManager* gpm = GPUProcessManager::Get();
+  if (aEnable) {
+    if (!gfxConfig::IsEnabled(gfx::Feature::GPU_PROCESS)) {
+      gfxConfig::UserForceEnable(gfx::Feature::GPU_PROCESS, "xpcshell-test");
+    }
+    DebugOnly<nsresult> rv = gpm->EnsureGPUReady();
+    MOZ_ASSERT(rv != NS_ERROR_ILLEGAL_DURING_SHUTDOWN);
+  } else {
+    gfxConfig::UserDisable(gfx::Feature::GPU_PROCESS, "xpcshell-test");
+    gpm->KillProcess();
+  }
+
+  *_retval = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP GfxInfoBase::KillGPUProcessForTests() {
+  GPUProcessManager* gpm = GPUProcessManager::Get();
+  if (!gpm) {
+    // gfxPlatform has not been initialized.
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  gpm->KillProcess();
+  return NS_OK;
+}
+
+NS_IMETHODIMP GfxInfoBase::CrashGPUProcessForTests() {
+  GPUProcessManager* gpm = GPUProcessManager::Get();
+  if (!gpm) {
+    // gfxPlatform has not been initialized.
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  gpm->CrashProcess();
+  return NS_OK;
+}
+
+GfxInfoCollectorBase::GfxInfoCollectorBase() {
+  GfxInfoBase::AddCollector(this);
+}
+
+GfxInfoCollectorBase::~GfxInfoCollectorBase() {
+  GfxInfoBase::RemoveCollector(this);
+}
diff --git a/widget/GfxInfoBase.h b/widget/GfxInfoBase.h
new file mode 100644
index 0000000000..4d4b1a2def
--- /dev/null
+++ b/widget/GfxInfoBase.h
@@ -0,0 +1,182 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_GfxInfoBase_h__
+#define __mozilla_widget_GfxInfoBase_h__
+
+#include "GfxDriverInfo.h"
+#include "GfxInfoCollector.h"
+#include "gfxFeature.h"
+#include "gfxTelemetry.h"
+#include "js/Value.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/gfx/GraphicsMessages.h"
+#include "nsCOMPtr.h"
+#include "nsIGfxInfo.h"
+#include "nsIGfxInfoDebug.h"
+#include "nsIObserver.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "nsWeakReference.h"
+
+namespace mozilla {
+namespace widget {
+
+class GfxInfoBase : public nsIGfxInfo,
+                    public nsIObserver,
+                    public nsSupportsWeakReference
+#ifdef DEBUG
+    ,
+                    public nsIGfxInfoDebug
+#endif
+{
+ public:
+  GfxInfoBase();
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  // We only declare a subset of the nsIGfxInfo interface. It's up to derived
+  // classes to implement the rest of the interface.
+  // Derived classes need to use
+  // using GfxInfoBase::GetFeatureStatus;
+  // using GfxInfoBase::GetFeatureSuggestedDriverVersion;
+  // to import the relevant methods into their namespace.
+  NS_IMETHOD GetFeatureStatus(int32_t aFeature, nsACString& aFailureId,
+                              int32_t* _retval) override;
+  NS_IMETHOD GetFeatureSuggestedDriverVersion(int32_t aFeature,
+                                              nsAString& _retval) override;
+
+  NS_IMETHOD GetMonitors(JSContext* cx,
+                         JS::MutableHandle<JS::Value> _retval) override;
+  NS_IMETHOD GetFailures(nsTArray<int32_t>& indices,
+                         nsTArray<nsCString>& failures) override;
+  NS_IMETHOD_(void) LogFailure(const nsACString& failure) override;
+  NS_IMETHOD GetInfo(JSContext*, JS::MutableHandle<JS::Value>) override;
+  NS_IMETHOD GetFeatures(JSContext*, JS::MutableHandle<JS::Value>) override;
+  NS_IMETHOD GetFeatureLog(JSContext*, JS::MutableHandle<JS::Value>) override;
+  NS_IMETHOD GetActiveCrashGuards(JSContext*,
+                                  JS::MutableHandle<JS::Value>) override;
+  NS_IMETHOD GetFontVisibilityDetermination(
+      nsIGfxInfo::FontVisibilityDeviceDetermination*
+          aFontVisibilityDetermination) override;
+  NS_IMETHOD GetFontVisibilityDeterminationStr(
+      nsAString& aFontVisibilityDeterminationStr) override;
+  NS_IMETHOD GetContentBackend(nsAString& aContentBackend) override;
+  NS_IMETHOD GetAzureCanvasBackend(nsAString& aBackend) override;
+  NS_IMETHOD GetAzureContentBackend(nsAString& aBackend) override;
+  NS_IMETHOD GetUsingGPUProcess(bool* aOutValue) override;
+  NS_IMETHOD GetIsHeadless(bool* aIsHeadless) override;
+  NS_IMETHOD GetTargetFrameRate(uint32_t* aTargetFrameRate) override;
+  NS_IMETHOD GetCodecSupportInfo(nsACString& aCodecSupportInfo) override;
+
+  // Non-XPCOM method to get IPC data:
+  nsTArray<mozilla::gfx::GfxInfoFeatureStatus> GetAllFeatures();
+
+  // Initialization function. If you override this, you must call this class's
+  // version of Init first.
+  // We need Init to be called separately from the constructor so we can
+  // register as an observer after all derived classes have been constructed
+  // and we know we have a non-zero refcount.
+  // Ideally, Init() would be void-return, but the rules of
+  // NS_GENERIC_FACTORY_CONSTRUCTOR_INIT require it be nsresult return.
+  virtual nsresult Init();
+
+  NS_IMETHOD_(void) GetData() override;
+  NS_IMETHOD_(int32_t) GetMaxRefreshRate(bool* aMixed) override;
+
+  static void AddCollector(GfxInfoCollectorBase* collector);
+  static void RemoveCollector(GfxInfoCollectorBase* collector);
+
+  static nsTArray<GfxDriverInfo>* sDriverInfo;
+  static StaticAutoPtr<nsTArray<mozilla::gfx::GfxInfoFeatureStatus>>
+      sFeatureStatus;
+  static bool sDriverInfoObserverInitialized;
+  static bool sShutdownOccurred;
+
+  virtual nsString Model() { return u""_ns; }
+  virtual nsString Hardware() { return u""_ns; }
+  virtual nsString Product() { return u""_ns; }
+  virtual nsString Manufacturer() { return u""_ns; }
+  virtual uint32_t OperatingSystemVersion() { return 0; }
+  virtual uint32_t OperatingSystemBuild() { return 0; }
+
+  // Convenience to get the application version
+  static const nsCString& GetApplicationVersion();
+
+  virtual nsresult FindMonitors(JSContext* cx, JS::Handle<JSObject*> array);
+
+  static void SetFeatureStatus(
+      nsTArray<mozilla::gfx::GfxInfoFeatureStatus>&& aFS);
+
+  static bool OnlyAllowFeatureOnKnownConfig(int32_t aFeature);
+
+ protected:
+  virtual ~GfxInfoBase();
+
+  virtual OperatingSystem GetOperatingSystem() = 0;
+
+  virtual nsresult GetFeatureStatusImpl(
+      int32_t aFeature, int32_t* aStatus, nsAString& aSuggestedDriverVersion,
+      const nsTArray<GfxDriverInfo>& aDriverInfo, nsACString& aFailureId,
+      OperatingSystem* aOS = nullptr);
+
+  // Gets the driver info table. Used by GfxInfoBase to check for general cases
+  // (while subclasses check for more specific ones).
+  virtual const nsTArray<GfxDriverInfo>& GetGfxDriverInfo() = 0;
+
+  virtual void DescribeFeatures(JSContext* aCx, JS::Handle<JSObject*> obj);
+
+  virtual bool DoesWindowProtocolMatch(
+      const nsAString& aBlocklistWindowProtocol,
+      const nsAString& aWindowProtocol);
+
+  bool DoesVendorMatch(const nsAString& aBlocklistVendor,
+                       const nsAString& aAdapterVendor);
+
+  virtual bool DoesDriverVendorMatch(const nsAString& aBlocklistVendor,
+                                     const nsAString& aDriverVendor);
+
+  bool InitFeatureObject(JSContext* aCx, JS::Handle<JSObject*> aContainer,
+                         const char* aName,
+                         mozilla::gfx::FeatureState& aFeatureState,
+                         JS::MutableHandle<JSObject*> aOutObj);
+
+  NS_IMETHOD ControlGPUProcessForXPCShell(bool aEnable, bool* _retval) override;
+
+  NS_IMETHOD KillGPUProcessForTests() override;
+  NS_IMETHOD CrashGPUProcessForTests() override;
+
+  // Total number of pixels for all detected screens at startup.
+  int64_t mScreenPixels;
+
+ private:
+  virtual int32_t FindBlocklistedDeviceInList(
+      const nsTArray<GfxDriverInfo>& aDriverInfo, nsAString& aSuggestedVersion,
+      int32_t aFeature, nsACString& aFailureId, OperatingSystem os,
+      bool aForAllowing);
+
+  std::pair<nsIGfxInfo::FontVisibilityDeviceDetermination, nsString>*
+  GetFontVisibilityDeterminationPair();
+
+  bool IsFeatureAllowlisted(int32_t aFeature) const;
+
+  void EvaluateDownloadedBlocklist(nsTArray<GfxDriverInfo>& aDriverInfo);
+
+  bool BuildFeatureStateLog(JSContext* aCx, const gfx::FeatureState& aFeature,
+                            JS::MutableHandle<JS::Value> aOut);
+
+  Mutex mMutex MOZ_UNANNOTATED;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __mozilla_widget_GfxInfoBase_h__ */
diff --git a/widget/GfxInfoCollector.cpp b/widget/GfxInfoCollector.cpp
new file mode 100644
index 0000000000..6ad8494586
--- /dev/null
+++ b/widget/GfxInfoCollector.cpp
@@ -0,0 +1,44 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GfxInfoCollector.h"
+#include "jsapi.h"
+#include "js/PropertyAndElement.h"  // JS_DefineProperty
+#include "nsString.h"
+
+using namespace mozilla;
+using namespace widget;
+
+void InfoObject::DefineProperty(const char* name, int value) {
+  if (!mOk) return;
+
+  mOk = JS_DefineProperty(mCx, mObj, name, value, JSPROP_ENUMERATE);
+}
+
+void InfoObject::DefineProperty(const char* name, const nsAString& value) {
+  if (!mOk) return;
+
+  const nsString& flat = PromiseFlatString(value);
+  JS::Rooted<JSString*> string(
+      mCx, JS_NewUCStringCopyN(mCx, static_cast<const char16_t*>(flat.get()),
+                               flat.Length()));
+  if (!string) mOk = false;
+
+  if (!mOk) return;
+
+  mOk = JS_DefineProperty(mCx, mObj, name, string, JSPROP_ENUMERATE);
+}
+
+void InfoObject::DefineProperty(const char* name, const char* value) {
+  nsAutoString string = NS_ConvertASCIItoUTF16(value);
+  DefineProperty(name, string);
+}
+
+InfoObject::InfoObject(JSContext* aCx) : mCx(aCx), mObj(aCx), mOk(true) {
+  mObj = JS_NewPlainObject(aCx);
+  if (!mObj) mOk = false;
+}
diff --git a/widget/GfxInfoCollector.h b/widget/GfxInfoCollector.h
new file mode 100644
index 0000000000..7108a7fe2d
--- /dev/null
+++ b/widget/GfxInfoCollector.h
@@ -0,0 +1,88 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_GfxInfoCollector_h__
+#define __mozilla_widget_GfxInfoCollector_h__
+
+#include "mozilla/Attributes.h"
+#include "nsStringFwd.h"
+#include "js/RootingAPI.h"
+
+namespace mozilla {
+namespace widget {
+
+/* this is handy wrapper around JSAPI to make it more pleasant to use.
+ * We collect the JSAPI errors and so that callers don't need to */
+class MOZ_STACK_CLASS InfoObject {
+  friend class GfxInfoBase;
+
+ public:
+  void DefineProperty(const char* name, int value);
+  void DefineProperty(const char* name, const nsAString& value);
+  void DefineProperty(const char* name, const char* value);
+
+ private:
+  // We need to ensure that this object lives on the stack so that GC sees it
+  // properly
+  explicit InfoObject(JSContext* aCx);
+  InfoObject(InfoObject&);
+
+  JSContext* mCx;
+  JS::Rooted<JSObject*> mObj;
+  bool mOk;
+};
+
+/*
+
+   Here's an example usage:
+
+   class Foo {
+   Foo::Foo() : mInfoCollector(this, &Foo::GetAweseomeness) {}
+
+   void GetAwesomeness(InfoObject &obj) {
+     obj.DefineProperty("awesome", mAwesome);
+   }
+
+   int mAwesome;
+
+   GfxInfoCollector<Foo> mInfoCollector;
+   }
+
+   This will define a property on the object
+   returned from calling getInfo() on a
+   GfxInfo object. e.g.
+
+       gfxInfo = Cc["@mozilla.org/gfx/info;1"].getService(Ci.nsIGfxInfo);
+       info = gfxInfo.getInfo();
+       if (info.awesome)
+          alert(info.awesome);
+
+*/
+
+class GfxInfoCollectorBase {
+ public:
+  GfxInfoCollectorBase();
+  virtual void GetInfo(InfoObject& obj) = 0;
+  virtual ~GfxInfoCollectorBase();
+};
+
+template <class T>
+class GfxInfoCollector : public GfxInfoCollectorBase {
+ public:
+  GfxInfoCollector(T* aPointer, void (T::*aFunc)(InfoObject& obj))
+      : mPointer(aPointer), mFunc(aFunc) {}
+  virtual void GetInfo(InfoObject& obj) override { (mPointer->*mFunc)(obj); }
+
+ protected:
+  T* mPointer;
+  void (T::*mFunc)(InfoObject& obj);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/IMEData.cpp b/widget/IMEData.cpp
new file mode 100644
index 0000000000..f9497a648d
--- /dev/null
+++ b/widget/IMEData.cpp
@@ -0,0 +1,418 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "IMEData.h"
+
+#include <sstream>
+
+#include "ContentData.h"
+#include "gfxFontUtils.h"
+#include "TextEvents.h"
+
+#include "mozilla/Maybe.h"
+#include "mozilla/ToString.h"
+#include "mozilla/WritingModes.h"
+
+#include "nsPrintfCString.h"
+#include "nsString.h"
+
+namespace mozilla {
+
+template PrintStringDetail::PrintStringDetail(
+    const Maybe<nsString>& aMaybeString, uint32_t aMaxLength);
+
+template <typename StringType>
+PrintStringDetail::PrintStringDetail(const Maybe<StringType>& aMaybeString,
+                                     uint32_t aMaxLength /* = UINT32_MAX */)
+    : PrintStringDetail(aMaybeString.refOr(EmptyString()), aMaxLength) {
+  if (aMaybeString.isNothing()) {
+    AssignASCII(ToString(aMaybeString).c_str());
+  }
+}
+
+PrintStringDetail::PrintStringDetail(const nsAString& aString,
+                                     uint32_t aMaxLength /* = UINT32_MAX */) {
+  Assign("\"");
+  const uint32_t kFirstHalf =
+      aString.Length() <= aMaxLength ? UINT32_MAX : (aMaxLength + 1) / 2;
+  const uint32_t kSecondHalf =
+      aString.Length() <= aMaxLength ? 0 : aMaxLength / 2;
+  for (uint32_t i = 0; i < aString.Length(); i++) {
+    if (i > 0) {
+      AppendLiteral(" ");
+    }
+    char32_t ch = aString.CharAt(i);
+    if (NS_IS_HIGH_SURROGATE(ch) && i + 1 < aString.Length() &&
+        NS_IS_LOW_SURROGATE(aString.CharAt(i + 1))) {
+      ch = SURROGATE_TO_UCS4(ch, aString.CharAt(i + 1));
+    }
+    Append(PrintCharData(ch));
+    if (i + 1 == kFirstHalf) {
+      AppendLiteral(" ...");
+      i = aString.Length() - kSecondHalf - 1;
+      if (NS_IS_LOW_SURROGATE(aString.CharAt(i)) &&
+          NS_IS_HIGH_SURROGATE(aString.CharAt(i - 1))) {
+        if (i - 1 <= kFirstHalf) {
+          i++;
+        } else {
+          i--;
+        }
+      }
+    } else if (!IS_IN_BMP(ch)) {
+      i++;
+    }
+  }
+  AppendLiteral("\" (Length()=");
+  AppendInt(static_cast<uint32_t>(aString.Length()));
+  AppendLiteral(")");
+}
+
+// static
+nsCString PrintStringDetail::PrintCharData(char32_t aChar) {
+  switch (aChar) {
+    case 0x0000:
+      return "NULL (0x0000)"_ns;
+    case 0x0008:
+      return "BACKSPACE (0x0008)"_ns;
+    case 0x0009:
+      return "CHARACTER TABULATION (0x0009)"_ns;
+    case 0x000A:
+      return "LINE FEED (0x000A)"_ns;
+    case 0x000B:
+      return "LINE TABULATION (0x000B)"_ns;
+    case 0x000C:
+      return "FORM FEED (0x000C)"_ns;
+    case 0x000D:
+      return "CARRIAGE RETURN (0x000D)"_ns;
+    case 0x0018:
+      return "CANCEL (0x0018)"_ns;
+    case 0x001B:
+      return "ESCAPE (0x001B)"_ns;
+    case 0x0020:
+      return "SPACE (0x0020)"_ns;
+    case 0x007F:
+      return "DELETE (0x007F)"_ns;
+    case 0x00A0:
+      return "NO-BREAK SPACE (0x00A0)"_ns;
+    case 0x00AD:
+      return "SOFT HYPHEN (0x00AD)"_ns;
+    case 0x2000:
+      return "EN QUAD (0x2000)"_ns;
+    case 0x2001:
+      return "EM QUAD (0x2001)"_ns;
+    case 0x2002:
+      return "EN SPACE (0x2002)"_ns;
+    case 0x2003:
+      return "EM SPACE (0x2003)"_ns;
+    case 0x2004:
+      return "THREE-PER-EM SPACE (0x2004)"_ns;
+    case 0x2005:
+      return "FOUR-PER-EM SPACE (0x2005)"_ns;
+    case 0x2006:
+      return "SIX-PER-EM SPACE (0x2006)"_ns;
+    case 0x2007:
+      return "FIGURE SPACE (0x2007)"_ns;
+    case 0x2008:
+      return "PUNCTUATION SPACE (0x2008)"_ns;
+    case 0x2009:
+      return "THIN SPACE (0x2009)"_ns;
+    case 0x200A:
+      return "HAIR SPACE (0x200A)"_ns;
+    case 0x200B:
+      return "ZERO WIDTH SPACE (0x200B)"_ns;
+    case 0x200C:
+      return "ZERO WIDTH NON-JOINER (0x200C)"_ns;
+    case 0x200D:
+      return "ZERO WIDTH JOINER (0x200D)"_ns;
+    case 0x200E:
+      return "LEFT-TO-RIGHT MARK (0x200E)"_ns;
+    case 0x200F:
+      return "RIGHT-TO-LEFT MARK (0x200F)"_ns;
+    case 0x2029:
+      return "PARAGRAPH SEPARATOR (0x2029)"_ns;
+    case 0x202A:
+      return "LEFT-TO-RIGHT EMBEDDING (0x202A)"_ns;
+    case 0x202B:
+      return "RIGHT-TO-LEFT EMBEDDING (0x202B)"_ns;
+    case 0x202D:
+      return "LEFT-TO-RIGHT OVERRIDE (0x202D)"_ns;
+    case 0x202E:
+      return "RIGHT-TO-LEFT OVERRIDE (0x202E)"_ns;
+    case 0x202F:
+      return "NARROW NO-BREAK SPACE (0x202F)"_ns;
+    case 0x205F:
+      return "MEDIUM MATHEMATICAL SPACE (0x205F)"_ns;
+    case 0x2060:
+      return "WORD JOINER (0x2060)"_ns;
+    case 0x2066:
+      return "LEFT-TO-RIGHT ISOLATE (0x2066)"_ns;
+    case 0x2067:
+      return "RIGHT-TO-LEFT ISOLATE (0x2067)"_ns;
+    case 0x3000:
+      return "IDEOGRAPHIC SPACE (0x3000)"_ns;
+    case 0xFEFF:
+      return "ZERO WIDTH NO-BREAK SPACE (0xFEFF)"_ns;
+    default: {
+      if (aChar < ' ' || (aChar >= 0x80 && aChar < 0xA0)) {
+        return nsPrintfCString("Control (0x%04X)", aChar);
+      }
+      if (NS_IS_HIGH_SURROGATE(aChar)) {
+        return nsPrintfCString("High Surrogate (0x%04X)", aChar);
+      }
+      if (NS_IS_LOW_SURROGATE(aChar)) {
+        return nsPrintfCString("Low Surrogate (0x%04X)", aChar);
+      }
+      if (gfxFontUtils::IsVarSelector(aChar)) {
+        return IS_IN_BMP(aChar)
+                   ? nsPrintfCString("Variant Selector (0x%04X)", aChar)
+                   : nsPrintfCString("Variant Selector (0x%08X)", aChar);
+      }
+      nsAutoString utf16Str;
+      AppendUCS4ToUTF16(aChar, utf16Str);
+      return IS_IN_BMP(aChar)
+                 ? nsPrintfCString("'%s' (0x%04X)",
+                                   NS_ConvertUTF16toUTF8(utf16Str).get(), aChar)
+                 : nsPrintfCString("'%s' (0x%08X)",
+                                   NS_ConvertUTF16toUTF8(utf16Str).get(),
+                                   aChar);
+    }
+  }
+}
+
+namespace widget {
+
+std::ostream& operator<<(std::ostream& aStream, const IMEEnabled& aEnabled) {
+  switch (aEnabled) {
+    case IMEEnabled::Disabled:
+      return aStream << "DISABLED";
+    case IMEEnabled::Enabled:
+      return aStream << "ENABLED";
+    case IMEEnabled::Password:
+      return aStream << "PASSWORD";
+    case IMEEnabled::Unknown:
+      return aStream << "illegal value";
+  }
+  MOZ_ASSERT_UNREACHABLE("Add a case to handle your new IMEEnabled value");
+  return aStream;
+}
+
+std::ostream& operator<<(std::ostream& aStream, const IMEState::Open& aOpen) {
+  switch (aOpen) {
+    case IMEState::DONT_CHANGE_OPEN_STATE:
+      aStream << "DONT_CHANGE_OPEN_STATE";
+      break;
+    case IMEState::OPEN:
+      aStream << "OPEN";
+      break;
+    case IMEState::CLOSED:
+      aStream << "CLOSED";
+      break;
+    default:
+      aStream << "illegal value";
+      break;
+  }
+  return aStream;
+}
+
+std::ostream& operator<<(std::ostream& aStream, const IMEState& aState) {
+  aStream << "{ mEnabled=" << aState.mEnabled << ", mOpen=" << aState.mOpen
+          << " }";
+  return aStream;
+}
+
+std::ostream& operator<<(std::ostream& aStream,
+                         const InputContext::Origin& aOrigin) {
+  switch (aOrigin) {
+    case InputContext::ORIGIN_MAIN:
+      aStream << "ORIGIN_MAIN";
+      break;
+    case InputContext::ORIGIN_CONTENT:
+      aStream << "ORIGIN_CONTENT";
+      break;
+    default:
+      aStream << "illegal value";
+      break;
+  }
+  return aStream;
+}
+
+std::ostream& operator<<(std::ostream& aStream, const InputContext& aContext) {
+  aStream << "{ mIMEState=" << aContext.mIMEState
+          << ", mOrigin=" << aContext.mOrigin << ", mHTMLInputType=\""
+          << aContext.mHTMLInputType << "\", mHTMLInputMode=\""
+          << aContext.mHTMLInputMode << "\", mActionHint=\""
+          << aContext.mActionHint << "\", mAutocapitalize=\""
+          << aContext.mAutocapitalize << "\", mIsPrivateBrowsing="
+          << (aContext.mInPrivateBrowsing ? "true" : "false") << " }";
+  return aStream;
+}
+
+std::ostream& operator<<(std::ostream& aStream,
+                         const InputContextAction::Cause& aCause) {
+  switch (aCause) {
+    case InputContextAction::CAUSE_UNKNOWN:
+      aStream << "CAUSE_UNKNOWN";
+      break;
+    case InputContextAction::CAUSE_UNKNOWN_CHROME:
+      aStream << "CAUSE_UNKNOWN_CHROME";
+      break;
+    case InputContextAction::CAUSE_KEY:
+      aStream << "CAUSE_KEY";
+      break;
+    case InputContextAction::CAUSE_MOUSE:
+      aStream << "CAUSE_MOUSE";
+      break;
+    case InputContextAction::CAUSE_TOUCH:
+      aStream << "CAUSE_TOUCH";
+      break;
+    case InputContextAction::CAUSE_LONGPRESS:
+      aStream << "CAUSE_LONGPRESS";
+      break;
+    case InputContextAction::CAUSE_UNKNOWN_DURING_NON_KEYBOARD_INPUT:
+      aStream << "CAUSE_UNKNOWN_DURING_NON_KEYBOARD_INPUT";
+      break;
+    case InputContextAction::CAUSE_UNKNOWN_DURING_KEYBOARD_INPUT:
+      aStream << "CAUSE_UNKNOWN_DURING_KEYBOARD_INPUT";
+      break;
+    default:
+      aStream << "illegal value";
+      break;
+  }
+  return aStream;
+}
+
+std::ostream& operator<<(std::ostream& aStream,
+                         const InputContextAction::FocusChange& aFocusChange) {
+  switch (aFocusChange) {
+    case InputContextAction::FOCUS_NOT_CHANGED:
+      aStream << "FOCUS_NOT_CHANGED";
+      break;
+    case InputContextAction::GOT_FOCUS:
+      aStream << "GOT_FOCUS";
+      break;
+    case InputContextAction::LOST_FOCUS:
+      aStream << "LOST_FOCUS";
+      break;
+    case InputContextAction::MENU_GOT_PSEUDO_FOCUS:
+      aStream << "MENU_GOT_PSEUDO_FOCUS";
+      break;
+    case InputContextAction::MENU_LOST_PSEUDO_FOCUS:
+      aStream << "MENU_LOST_PSEUDO_FOCUS";
+      break;
+    case InputContextAction::WIDGET_CREATED:
+      aStream << "WIDGET_CREATED";
+      break;
+    default:
+      aStream << "illegal value";
+      break;
+  }
+  return aStream;
+}
+
+std::ostream& operator<<(
+    std::ostream& aStream,
+    const IMENotification::SelectionChangeDataBase& aData) {
+  if (!aData.IsInitialized()) {
+    aStream << "{ IsInitialized()=false }";
+    return aStream;
+  }
+  if (!aData.HasRange()) {
+    aStream << "{ HasRange()=false }";
+    return aStream;
+  }
+  aStream << "{ mOffset=" << aData.mOffset;
+  if (aData.mString->Length() > 20) {
+    aStream << ", mString.Length()=" << aData.mString->Length();
+  } else {
+    aStream << ", mString=\"" << NS_ConvertUTF16toUTF8(*aData.mString)
+            << "\" (Length()=" << aData.mString->Length() << ")";
+  }
+
+  aStream << ", GetWritingMode()=" << aData.GetWritingMode()
+          << ", mReversed=" << (aData.mReversed ? "true" : "false")
+          << ", mCausedByComposition="
+          << (aData.mCausedByComposition ? "true" : "false")
+          << ", mCausedBySelectionEvent="
+          << (aData.mCausedBySelectionEvent ? "true" : "false")
+          << ", mOccurredDuringComposition="
+          << (aData.mOccurredDuringComposition ? "true" : "false") << " }";
+  return aStream;
+}
+
+std::ostream& operator<<(std::ostream& aStream,
+                         const IMENotification::TextChangeDataBase& aData) {
+  if (!aData.IsValid()) {
+    aStream << "{ IsValid()=false }";
+    return aStream;
+  }
+  aStream << "{ mStartOffset=" << aData.mStartOffset
+          << ", mRemoveEndOffset=" << aData.mRemovedEndOffset
+          << ", mAddedEndOffset=" << aData.mAddedEndOffset
+          << ", mCausedOnlyByComposition="
+          << (aData.mCausedOnlyByComposition ? "true" : "false")
+          << ", mIncludingChangesDuringComposition="
+          << (aData.mIncludingChangesDuringComposition ? "true" : "false")
+          << ", mIncludingChangesWithoutComposition="
+          << (aData.mIncludingChangesWithoutComposition ? "true" : "false")
+          << " }";
+  return aStream;
+}
+
+/******************************************************************************
+ * IMENotification::SelectionChangeDataBase
+ ******************************************************************************/
+
+void IMENotification::SelectionChangeDataBase::Assign(
+    const WidgetQueryContentEvent& aQuerySelectedTextEvent) {
+  MOZ_ASSERT(aQuerySelectedTextEvent.mMessage == eQuerySelectedText);
+  MOZ_ASSERT(aQuerySelectedTextEvent.Succeeded());
+
+  if (!(mIsInitialized = aQuerySelectedTextEvent.Succeeded())) {
+    ClearSelectionData();
+    return;
+  }
+  if ((mHasRange = aQuerySelectedTextEvent.FoundSelection())) {
+    mOffset = aQuerySelectedTextEvent.mReply->StartOffset();
+    *mString = aQuerySelectedTextEvent.mReply->DataRef();
+    mReversed = aQuerySelectedTextEvent.mReply->mReversed;
+    SetWritingMode(aQuerySelectedTextEvent.mReply->WritingModeRef());
+  } else {
+    mOffset = UINT32_MAX;
+    mString->Truncate();
+    mReversed = false;
+    // Let's keep the writing mode for avoiding temporarily changing the
+    // writing mode at no selection range.
+  }
+}
+
+void IMENotification::SelectionChangeDataBase::SetWritingMode(
+    const WritingMode& aWritingMode) {
+  mWritingModeBits = aWritingMode.GetBits();
+}
+
+WritingMode IMENotification::SelectionChangeDataBase::GetWritingMode() const {
+  return WritingMode(mWritingModeBits);
+}
+
+bool IMENotification::SelectionChangeDataBase::EqualsRange(
+    const ContentSelection& aContentSelection) const {
+  if (aContentSelection.HasRange() != HasRange()) {
+    return false;
+  }
+  if (!HasRange()) {
+    return true;
+  }
+  return mOffset == aContentSelection.OffsetAndDataRef().StartOffset() &&
+         *mString == aContentSelection.OffsetAndDataRef().DataRef();
+}
+
+bool IMENotification::SelectionChangeDataBase::EqualsRangeAndWritingMode(
+    const ContentSelection& aContentSelection) const {
+  return EqualsRange(aContentSelection) &&
+         mWritingModeBits == aContentSelection.WritingModeRef().GetBits();
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/IMEData.h b/widget/IMEData.h
new file mode 100644
index 0000000000..7fb1241333
--- /dev/null
+++ b/widget/IMEData.h
@@ -0,0 +1,1085 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_IMEData_h_
+#define mozilla_widget_IMEData_h_
+
+#include "mozilla/CheckedInt.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/ToString.h"
+
+#include "nsCOMPtr.h"
+#include "nsIURI.h"
+#include "nsPoint.h"
+#include "nsRect.h"
+#include "nsString.h"
+#include "nsXULAppAPI.h"
+#include "Units.h"
+
+class nsIWidget;
+
+namespace mozilla {
+
+class ContentSelection;
+class WritingMode;
+
+template <class T>
+class Maybe;
+
+// Helper class to logging string which may contain various Unicode characters
+// and/or may be too long string for logging.
+class MOZ_STACK_CLASS PrintStringDetail : public nsAutoCString {
+ public:
+  static constexpr uint32_t kMaxLengthForCompositionString = 8;
+  static constexpr uint32_t kMaxLengthForSelectedString = 12;
+  static constexpr uint32_t kMaxLengthForEditor = 20;
+
+  PrintStringDetail() = delete;
+  explicit PrintStringDetail(const nsAString& aString,
+                             uint32_t aMaxLength = UINT32_MAX);
+  template <typename StringType>
+  explicit PrintStringDetail(const Maybe<StringType>& aMaybeString,
+                             uint32_t aMaxLength = UINT32_MAX);
+
+ private:
+  static nsCString PrintCharData(char32_t aChar);
+};
+
+// StartAndEndOffsets represents a range in flat-text.
+template <typename IntType>
+class StartAndEndOffsets {
+ protected:
+  static IntType MaxOffset() { return std::numeric_limits<IntType>::max(); }
+
+ public:
+  StartAndEndOffsets() = delete;
+  explicit StartAndEndOffsets(IntType aStartOffset, IntType aEndOffset)
+      : mStartOffset(aStartOffset),
+        mEndOffset(aStartOffset <= aEndOffset ? aEndOffset : aStartOffset) {
+    MOZ_ASSERT(aStartOffset <= mEndOffset);
+  }
+
+  IntType StartOffset() const { return mStartOffset; }
+  IntType Length() const { return mEndOffset - mStartOffset; }
+  IntType EndOffset() const { return mEndOffset; }
+
+  bool IsOffsetInRange(IntType aOffset) const {
+    return aOffset >= mStartOffset && aOffset < mEndOffset;
+  }
+  bool IsOffsetInRangeOrEndOffset(IntType aOffset) const {
+    return aOffset >= mStartOffset && aOffset <= mEndOffset;
+  }
+
+  void MoveTo(IntType aNewStartOffset) {
+    auto delta = static_cast<int64_t>(mStartOffset) - aNewStartOffset;
+    mStartOffset += delta;
+    mEndOffset += delta;
+  }
+  void SetOffsetAndLength(IntType aNewOffset, IntType aNewLength) {
+    mStartOffset = aNewOffset;
+    CheckedInt<IntType> endOffset(aNewOffset + aNewLength);
+    mEndOffset = endOffset.isValid() ? endOffset.value() : MaxOffset();
+  }
+  void SetEndOffset(IntType aEndOffset) {
+    MOZ_ASSERT(mStartOffset <= aEndOffset);
+    mEndOffset = std::max(aEndOffset, mStartOffset);
+  }
+  void SetStartAndEndOffsets(IntType aStartOffset, IntType aEndOffset) {
+    MOZ_ASSERT(aStartOffset <= aEndOffset);
+    mStartOffset = aStartOffset;
+    mEndOffset = aStartOffset <= aEndOffset ? aEndOffset : aStartOffset;
+  }
+  void SetLength(IntType aNewLength) {
+    CheckedInt<IntType> endOffset(mStartOffset + aNewLength);
+    mEndOffset = endOffset.isValid() ? endOffset.value() : MaxOffset();
+  }
+
+  friend std::ostream& operator<<(
+      std::ostream& aStream,
+      const StartAndEndOffsets<IntType>& aStartAndEndOffsets) {
+    aStream << "{ mStartOffset=" << aStartAndEndOffsets.mStartOffset
+            << ", mEndOffset=" << aStartAndEndOffsets.mEndOffset
+            << ", Length()=" << aStartAndEndOffsets.Length() << " }";
+    return aStream;
+  }
+
+ private:
+  IntType mStartOffset;
+  IntType mEndOffset;
+};
+
+// OffsetAndData class is designed for storing composition string and its
+// start offset.  Length() and EndOffset() return only valid length or
+// offset.  I.e., if the string is too long for inserting at the offset,
+// the length is shrunken.  However, the string itself is not shrunken.
+// Therefore, moving it to where all of the string can be contained,
+// they will return longer/bigger value.
+enum class OffsetAndDataFor {
+  CompositionString,
+  SelectedString,
+  EditorString,
+};
+template <typename IntType>
+class OffsetAndData {
+ protected:
+  static IntType MaxOffset() { return std::numeric_limits<IntType>::max(); }
+
+ public:
+  OffsetAndData() = delete;
+  explicit OffsetAndData(
+      IntType aStartOffset, const nsAString& aData,
+      OffsetAndDataFor aFor = OffsetAndDataFor::CompositionString)
+      : mData(aData), mOffset(aStartOffset), mFor(aFor) {}
+
+  bool IsValid() const {
+    CheckedInt<IntType> offset(mOffset);
+    offset += mData.Length();
+    return offset.isValid();
+  }
+  IntType StartOffset() const { return mOffset; }
+  IntType Length() const {
+    CheckedInt<IntType> endOffset(CheckedInt<IntType>(mOffset) +
+                                  mData.Length());
+    return endOffset.isValid() ? mData.Length() : MaxOffset() - mOffset;
+  }
+  IntType EndOffset() const { return mOffset + Length(); }
+  StartAndEndOffsets<IntType> CreateStartAndEndOffsets() const {
+    return StartAndEndOffsets<IntType>(StartOffset(), EndOffset());
+  }
+  const nsString& DataRef() const {
+    // In strictly speaking, we should return substring which may be shrunken
+    // for rounding to the max offset.  However, it's unrealistic edge case,
+    // and creating new string is not so cheap job in a hot path.  Therefore,
+    // this just returns the data as-is.
+    return mData;
+  }
+  bool IsDataEmpty() const { return mData.IsEmpty(); }
+
+  bool IsOffsetInRange(IntType aOffset) const {
+    return aOffset >= mOffset && aOffset < EndOffset();
+  }
+  bool IsOffsetInRangeOrEndOffset(IntType aOffset) const {
+    return aOffset >= mOffset && aOffset <= EndOffset();
+  }
+
+  void Collapse(IntType aOffset) {
+    mOffset = aOffset;
+    mData.Truncate();
+  }
+  void MoveTo(IntType aNewOffset) { mOffset = aNewOffset; }
+  void SetOffsetAndData(IntType aStartOffset, const nsAString& aData) {
+    mOffset = aStartOffset;
+    mData = aData;
+  }
+  void SetData(const nsAString& aData) { mData = aData; }
+  void TruncateData(uint32_t aLength = 0) { mData.Truncate(aLength); }
+  void ReplaceData(nsAString::size_type aCutStart,
+                   nsAString::size_type aCutLength,
+                   const nsAString& aNewString) {
+    mData.Replace(aCutStart, aCutLength, aNewString);
+  }
+
+  friend std::ostream& operator<<(
+      std::ostream& aStream, const OffsetAndData<IntType>& aOffsetAndData) {
+    const auto maxDataLength =
+        aOffsetAndData.mFor == OffsetAndDataFor::CompositionString
+            ? PrintStringDetail::kMaxLengthForCompositionString
+            : (aOffsetAndData.mFor == OffsetAndDataFor::SelectedString
+                   ? PrintStringDetail::kMaxLengthForSelectedString
+                   : PrintStringDetail::kMaxLengthForEditor);
+    aStream << "{ mOffset=" << aOffsetAndData.mOffset << ", mData="
+            << PrintStringDetail(aOffsetAndData.mData, maxDataLength).get()
+            << ", Length()=" << aOffsetAndData.Length()
+            << ", EndOffset()=" << aOffsetAndData.EndOffset() << " }";
+    return aStream;
+  }
+
+ private:
+  nsString mData;
+  IntType mOffset;
+  OffsetAndDataFor mFor;
+};
+
+namespace widget {
+
+/**
+ * Preference for receiving IME updates
+ *
+ * If mWantUpdates is not NOTIFY_NOTHING, nsTextStateManager will observe text
+ * change and/or selection change and call nsIWidget::NotifyIME() with
+ * NOTIFY_IME_OF_SELECTION_CHANGE and/or NOTIFY_IME_OF_TEXT_CHANGE.
+ * Please note that the text change observing cost is very expensive especially
+ * on an HTML editor has focus.
+ * If the IME implementation on a particular platform doesn't care about
+ * NOTIFY_IME_OF_SELECTION_CHANGE and/or NOTIFY_IME_OF_TEXT_CHANGE,
+ * they should set mWantUpdates to NOTIFY_NOTHING to avoid the cost.
+ * If the IME implementation needs notifications even while our process is
+ * deactive, it should also set NOTIFY_DURING_DEACTIVE.
+ */
+struct IMENotificationRequests final {
+  typedef uint8_t Notifications;
+
+  enum : Notifications {
+    NOTIFY_NOTHING = 0,
+    NOTIFY_TEXT_CHANGE = 1 << 1,
+    NOTIFY_POSITION_CHANGE = 1 << 2,
+    // NOTIFY_MOUSE_BUTTON_EVENT_ON_CHAR is used when mouse button is pressed
+    // or released on a character in the focused editor.  The notification is
+    // notified to IME as a mouse event.  If it's consumed by IME, NotifyIME()
+    // returns NS_SUCCESS_EVENT_CONSUMED.  Otherwise, it returns NS_OK if it's
+    // handled without any error.
+    NOTIFY_MOUSE_BUTTON_EVENT_ON_CHAR = 1 << 3,
+    // NOTE: NOTIFY_DURING_DEACTIVE isn't supported in environments where two
+    //       or more compositions are possible.  E.g., Mac and Linux (GTK).
+    NOTIFY_DURING_DEACTIVE = 1 << 7,
+
+    NOTIFY_ALL = NOTIFY_TEXT_CHANGE | NOTIFY_POSITION_CHANGE |
+                 NOTIFY_MOUSE_BUTTON_EVENT_ON_CHAR,
+  };
+
+  IMENotificationRequests() : mWantUpdates(NOTIFY_NOTHING) {}
+
+  explicit IMENotificationRequests(Notifications aWantUpdates)
+      : mWantUpdates(aWantUpdates) {}
+
+  IMENotificationRequests operator|(
+      const IMENotificationRequests& aOther) const {
+    return IMENotificationRequests(aOther.mWantUpdates | mWantUpdates);
+  }
+  IMENotificationRequests& operator|=(const IMENotificationRequests& aOther) {
+    mWantUpdates |= aOther.mWantUpdates;
+    return *this;
+  }
+  bool operator==(const IMENotificationRequests& aOther) const {
+    return mWantUpdates == aOther.mWantUpdates;
+  }
+
+  bool WantTextChange() const { return !!(mWantUpdates & NOTIFY_TEXT_CHANGE); }
+
+  bool WantPositionChanged() const {
+    return !!(mWantUpdates & NOTIFY_POSITION_CHANGE);
+  }
+
+  bool WantChanges() const { return WantTextChange(); }
+
+  bool WantMouseButtonEventOnChar() const {
+    return !!(mWantUpdates & NOTIFY_MOUSE_BUTTON_EVENT_ON_CHAR);
+  }
+
+  bool WantDuringDeactive() const {
+    return !!(mWantUpdates & NOTIFY_DURING_DEACTIVE);
+  }
+
+  Notifications mWantUpdates;
+};
+
+/**
+ * IME enabled states.
+ *
+ * WARNING: If you change these values, you also need to edit:
+ *   nsIDOMWindowUtils.idl
+ */
+enum class IMEEnabled {
+  /**
+   * 'Disabled' means the user cannot use IME. So, the IME open state should
+   * be 'closed' during 'disabled'.
+   */
+  Disabled,
+  /**
+   * 'Enabled' means the user can use IME.
+   */
+  Enabled,
+  /**
+   * 'Password' state is a special case for the password editors.
+   * E.g., on mac, the password editors should disable the non-Roman
+   * keyboard layouts at getting focus. Thus, the password editor may have
+   * special rules on some platforms.
+   */
+  Password,
+  /**
+   * 'Unknown' is useful when you cache this enum.  So, this shouldn't be
+   * used with nsIWidget::SetInputContext().
+   */
+  Unknown,
+};
+
+/**
+ * Contains IMEStatus plus information about the current
+ * input context that the IME can use as hints if desired.
+ */
+
+struct IMEState final {
+  IMEEnabled mEnabled;
+
+  /**
+   * IME open states the mOpen value of SetInputContext() should be one value of
+   * OPEN, CLOSE or DONT_CHANGE_OPEN_STATE.  GetInputContext() should return
+   * OPEN, CLOSE or OPEN_STATE_NOT_SUPPORTED.
+   */
+  enum Open {
+    /**
+     * 'Unsupported' means the platform cannot return actual IME open state.
+     * This value is used only by GetInputContext().
+     */
+    OPEN_STATE_NOT_SUPPORTED,
+    /**
+     * 'Don't change' means the widget shouldn't change IME open state when
+     * SetInputContext() is called.
+     */
+    DONT_CHANGE_OPEN_STATE = OPEN_STATE_NOT_SUPPORTED,
+    /**
+     * 'Open' means that IME should compose in its primary language (or latest
+     * input mode except direct ASCII character input mode).  Even if IME is
+     * opened by this value, users should be able to close IME by theirselves.
+     * Web contents can specify this value by |ime-mode: active;|.
+     */
+    OPEN,
+    /**
+     * 'Closed' means that IME shouldn't handle key events (or should handle
+     * as ASCII character inputs on mobile device).  Even if IME is closed by
+     * this value, users should be able to open IME by theirselves.
+     * Web contents can specify this value by |ime-mode: inactive;|.
+     */
+    CLOSED
+  };
+  Open mOpen;
+
+  IMEState() : mEnabled(IMEEnabled::Enabled), mOpen(DONT_CHANGE_OPEN_STATE) {}
+
+  explicit IMEState(IMEEnabled aEnabled, Open aOpen = DONT_CHANGE_OPEN_STATE)
+      : mEnabled(aEnabled), mOpen(aOpen) {}
+
+  // Returns true if the user can input characters.
+  // This means that a plain text editor, an HTML editor, a password editor or
+  // a plain text editor whose ime-mode is "disabled".
+  bool IsEditable() const {
+    return mEnabled == IMEEnabled::Enabled || mEnabled == IMEEnabled::Password;
+  }
+};
+
+// NS_ONLY_ONE_NATIVE_IME_CONTEXT is a special value of native IME context.
+// If there can be only one IME composition in a process, this can be used.
+#define NS_ONLY_ONE_NATIVE_IME_CONTEXT \
+  (reinterpret_cast<void*>(static_cast<intptr_t>(-1)))
+
+struct NativeIMEContext final {
+  // Pointer to native IME context.  Typically this is the result of
+  // nsIWidget::GetNativeData(NS_RAW_NATIVE_IME_CONTEXT) in the parent process.
+  // See also NS_ONLY_ONE_NATIVE_IME_CONTEXT.
+  uintptr_t mRawNativeIMEContext;
+  // Process ID of the origin of mNativeIMEContext.
+  // static_cast<uint64_t>(-1) if the instance is not initialized properly.
+  // 0 if the instance is originated in the parent process.
+  // 1 or greater if the instance is originated in a content process.
+  uint64_t mOriginProcessID;
+
+  NativeIMEContext() : mRawNativeIMEContext(0), mOriginProcessID(0) {
+    Init(nullptr);
+  }
+
+  explicit NativeIMEContext(nsIWidget* aWidget)
+      : mRawNativeIMEContext(0), mOriginProcessID(0) {
+    Init(aWidget);
+  }
+
+  bool IsValid() const {
+    return mRawNativeIMEContext &&
+           mOriginProcessID != static_cast<uint64_t>(-1);
+  }
+
+  bool IsOriginatedInParentProcess() const {
+    return mOriginProcessID != 0 &&
+           mOriginProcessID != static_cast<uint64_t>(-1);
+  }
+
+  void Init(nsIWidget* aWidget);
+  void InitWithRawNativeIMEContext(const void* aRawNativeIMEContext) {
+    InitWithRawNativeIMEContext(const_cast<void*>(aRawNativeIMEContext));
+  }
+  void InitWithRawNativeIMEContext(void* aRawNativeIMEContext);
+
+  bool operator==(const NativeIMEContext& aOther) const {
+    return mRawNativeIMEContext == aOther.mRawNativeIMEContext &&
+           mOriginProcessID == aOther.mOriginProcessID;
+  }
+  bool operator!=(const NativeIMEContext& aOther) const {
+    return !(*this == aOther);
+  }
+};
+
+struct InputContext final {
+  InputContext()
+      : mOrigin(XRE_IsParentProcess() ? ORIGIN_MAIN : ORIGIN_CONTENT),
+        mHasHandledUserInput(false),
+        mInPrivateBrowsing(false) {}
+
+  // If InputContext instance is a static variable, any heap allocated stuff
+  // of its members need to be deleted at XPCOM shutdown.  Otherwise, it's
+  // detected as memory leak.
+  void ShutDown() {
+    mURI = nullptr;
+    mHTMLInputType.Truncate();
+    mHTMLInputMode.Truncate();
+    mActionHint.Truncate();
+    mAutocapitalize.Truncate();
+  }
+
+  bool IsPasswordEditor() const {
+    return mHTMLInputType.LowerCaseEqualsLiteral("password");
+  }
+
+  NativeKeyBindingsType GetNativeKeyBindingsType() const {
+    MOZ_DIAGNOSTIC_ASSERT(mIMEState.IsEditable());
+    // See GetInputType in IMEStateManager.cpp
+    if (mHTMLInputType.IsEmpty()) {
+      return NativeKeyBindingsType::RichTextEditor;
+    }
+    return mHTMLInputType.EqualsLiteral("textarea")
+               ? NativeKeyBindingsType::MultiLineEditor
+               : NativeKeyBindingsType::SingleLineEditor;
+  }
+
+  // https://html.spec.whatwg.org/dev/interaction.html#autocapitalization
+  bool IsAutocapitalizeSupported() const {
+    return !mHTMLInputType.EqualsLiteral("password") &&
+           !mHTMLInputType.EqualsLiteral("url") &&
+           !mHTMLInputType.EqualsLiteral("email");
+  }
+
+  bool IsInputAttributeChanged(const InputContext& aOldContext) const {
+    return mIMEState.mEnabled != aOldContext.mIMEState.mEnabled ||
+#if defined(ANDROID) || defined(MOZ_WIDGET_GTK) || defined(XP_WIN)
+           // input type and inputmode are supported by Windows IME API, GTK
+           // IME API and Android IME API
+           mHTMLInputType != aOldContext.mHTMLInputType ||
+           mHTMLInputMode != aOldContext.mHTMLInputMode ||
+#endif
+#if defined(ANDROID) || defined(MOZ_WIDGET_GTK)
+           // autocapitalize is supported by Android IME API and GTK IME API
+           mAutocapitalize != aOldContext.mAutocapitalize ||
+#endif
+#if defined(ANDROID)
+           // enterkeyhint is only supported by Android IME API.
+           mActionHint != aOldContext.mActionHint ||
+#endif
+           false;
+  }
+
+  IMEState mIMEState;
+
+  // The URI of the document which has the editable element.
+  nsCOMPtr<nsIURI> mURI;
+
+  /* The type of the input if the input is a html input field */
+  nsString mHTMLInputType;
+
+  // The value of the inputmode
+  nsString mHTMLInputMode;
+
+  /* A hint for the action that is performed when the input is submitted */
+  nsString mActionHint;
+
+  /* A hint for autocapitalize */
+  nsString mAutocapitalize;
+
+  /**
+   * mOrigin indicates whether this focus event refers to main or remote
+   * content.
+   */
+  enum Origin {
+    // Adjusting focus of content on the main process
+    ORIGIN_MAIN,
+    // Adjusting focus of content in a remote process
+    ORIGIN_CONTENT
+  };
+  Origin mOrigin;
+
+  /**
+   * True if the document has ever received user input
+   */
+  bool mHasHandledUserInput;
+
+  /* Whether the owning document of the input element has been loaded
+   * in private browsing mode. */
+  bool mInPrivateBrowsing;
+
+  bool IsOriginMainProcess() const { return mOrigin == ORIGIN_MAIN; }
+
+  bool IsOriginContentProcess() const { return mOrigin == ORIGIN_CONTENT; }
+
+  bool IsOriginCurrentProcess() const {
+    if (XRE_IsParentProcess()) {
+      return IsOriginMainProcess();
+    }
+    return IsOriginContentProcess();
+  }
+};
+
+// FYI: Implemented in nsBaseWidget.cpp
+const char* ToChar(InputContext::Origin aOrigin);
+
+struct InputContextAction final {
+  /**
+   * mCause indicates what action causes calling nsIWidget::SetInputContext().
+   * It must be one of following values.
+   */
+  enum Cause {
+    // The cause is unknown but originated from content. Focus might have been
+    // changed by content script.
+    CAUSE_UNKNOWN,
+    // The cause is unknown but originated from chrome. Focus might have been
+    // changed by chrome script.
+    CAUSE_UNKNOWN_CHROME,
+    // The cause is user's keyboard operation.
+    CAUSE_KEY,
+    // The cause is user's mouse operation.
+    CAUSE_MOUSE,
+    // The cause is user's touch operation (implies mouse)
+    CAUSE_TOUCH,
+    // The cause is users' long press operation.
+    CAUSE_LONGPRESS,
+    // The cause is unknown but it occurs during user input except keyboard
+    // input.  E.g., an event handler of a user input event moves focus.
+    CAUSE_UNKNOWN_DURING_NON_KEYBOARD_INPUT,
+    // The cause is unknown but it occurs during keyboard input.
+    CAUSE_UNKNOWN_DURING_KEYBOARD_INPUT,
+  };
+  Cause mCause;
+
+  /**
+   * mFocusChange indicates what happened for focus.
+   */
+  enum FocusChange {
+    FOCUS_NOT_CHANGED,
+    // A content got focus.
+    GOT_FOCUS,
+    // Focused content lost focus.
+    LOST_FOCUS,
+    // Menu got pseudo focus that means focused content isn't changed but
+    // keyboard events will be handled by menu.
+    MENU_GOT_PSEUDO_FOCUS,
+    // Menu lost pseudo focus that means focused content will handle keyboard
+    // events.
+    MENU_LOST_PSEUDO_FOCUS,
+    // The widget is created.  When a widget is crated, it may need to notify
+    // IME module to initialize its native IME context.  In such case, this is
+    // used.  I.e., this isn't used by IMEStateManager.
+    WIDGET_CREATED
+  };
+  FocusChange mFocusChange;
+
+  bool ContentGotFocusByTrustedCause() const {
+    return (mFocusChange == GOT_FOCUS && mCause != CAUSE_UNKNOWN);
+  }
+
+  bool UserMightRequestOpenVKB() const {
+    // If focus is changed, user must not request to open VKB.
+    if (mFocusChange != FOCUS_NOT_CHANGED) {
+      return false;
+    }
+    switch (mCause) {
+      // If user clicks or touches focused editor, user must request to open
+      // VKB.
+      case CAUSE_MOUSE:
+      case CAUSE_TOUCH:
+      // If script does something during a user input and that causes changing
+      // input context, user might request to open VKB.  E.g., user clicks
+      // dummy editor and JS moves focus to an actual editable node.  However,
+      // this should return false if the user input is a keyboard event since
+      // physical keyboard operation shouldn't cause opening VKB.
+      case CAUSE_UNKNOWN_DURING_NON_KEYBOARD_INPUT:
+        return true;
+      default:
+        return false;
+    }
+  }
+
+  /**
+   * IsHandlingUserInput() returns true if it's caused by a user action directly
+   * or it's caused by script or something but it occurred while we're handling
+   * a user action.  E.g., when it's caused by Element.focus() in an event
+   * handler of a user input, this returns true.
+   */
+  static bool IsHandlingUserInput(Cause aCause) {
+    switch (aCause) {
+      case CAUSE_KEY:
+      case CAUSE_MOUSE:
+      case CAUSE_TOUCH:
+      case CAUSE_LONGPRESS:
+      case CAUSE_UNKNOWN_DURING_NON_KEYBOARD_INPUT:
+      case CAUSE_UNKNOWN_DURING_KEYBOARD_INPUT:
+        return true;
+      default:
+        return false;
+    }
+  }
+
+  bool IsHandlingUserInput() const { return IsHandlingUserInput(mCause); }
+
+  InputContextAction()
+      : mCause(CAUSE_UNKNOWN), mFocusChange(FOCUS_NOT_CHANGED) {}
+
+  explicit InputContextAction(Cause aCause,
+                              FocusChange aFocusChange = FOCUS_NOT_CHANGED)
+      : mCause(aCause), mFocusChange(aFocusChange) {}
+};
+
+// IMEMessage is shared by IMEStateManager and TextComposition.
+// Update values in GeckoEditable.java if you make changes here.
+// XXX Negative values are used in Android...
+typedef int8_t IMEMessageType;
+enum IMEMessage : IMEMessageType {
+  // This is used by IMENotification internally.  This means that the instance
+  // hasn't been initialized yet.
+  NOTIFY_IME_OF_NOTHING,
+  // An editable content is getting focus
+  NOTIFY_IME_OF_FOCUS,
+  // An editable content is losing focus
+  NOTIFY_IME_OF_BLUR,
+  // Selection in the focused editable content is changed
+  NOTIFY_IME_OF_SELECTION_CHANGE,
+  // Text in the focused editable content is changed
+  NOTIFY_IME_OF_TEXT_CHANGE,
+  // Notified when a dispatched composition event is handled by the
+  // contents.  This must be notified after the other notifications.
+  // Note that if a remote process has focus, this is notified only once when
+  // all dispatched events are handled completely.  So, the receiver shouldn't
+  // count number of received this notification for comparing with the number
+  // of dispatched events.
+  // NOTE: If a composition event causes moving focus from the focused editor,
+  //       this notification may not be notified as usual.  Even in such case,
+  //       NOTIFY_IME_OF_BLUR is always sent.  So, notification listeners
+  //       should tread the blur notification as including this if there is
+  //       pending composition events.
+  NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED,
+  // Position or size of focused element may be changed.
+  NOTIFY_IME_OF_POSITION_CHANGE,
+  // Mouse button event is fired on a character in focused editor
+  NOTIFY_IME_OF_MOUSE_BUTTON_EVENT,
+  // Request to commit current composition to IME
+  // (some platforms may not support)
+  REQUEST_TO_COMMIT_COMPOSITION,
+  // Request to cancel current composition to IME
+  // (some platforms may not support)
+  REQUEST_TO_CANCEL_COMPOSITION
+};
+
+// FYI: Implemented in nsBaseWidget.cpp
+const char* ToChar(IMEMessage aIMEMessage);
+
+struct IMENotification final {
+  IMENotification() : mMessage(NOTIFY_IME_OF_NOTHING), mSelectionChangeData() {}
+
+  IMENotification(const IMENotification& aOther)
+      : mMessage(NOTIFY_IME_OF_NOTHING) {
+    Assign(aOther);
+  }
+
+  ~IMENotification() { Clear(); }
+
+  MOZ_IMPLICIT IMENotification(IMEMessage aMessage)
+      : mMessage(aMessage), mSelectionChangeData() {
+    switch (aMessage) {
+      case NOTIFY_IME_OF_SELECTION_CHANGE:
+        mSelectionChangeData.mString = new nsString();
+        mSelectionChangeData.Clear();
+        break;
+      case NOTIFY_IME_OF_TEXT_CHANGE:
+        mTextChangeData.Clear();
+        break;
+      case NOTIFY_IME_OF_MOUSE_BUTTON_EVENT:
+        mMouseButtonEventData.mEventMessage = eVoidEvent;
+        mMouseButtonEventData.mOffset = UINT32_MAX;
+        mMouseButtonEventData.mCursorPos.MoveTo(0, 0);
+        mMouseButtonEventData.mCharRect.SetRect(0, 0, 0, 0);
+        mMouseButtonEventData.mButton = -1;
+        mMouseButtonEventData.mButtons = 0;
+        mMouseButtonEventData.mModifiers = 0;
+        break;
+      default:
+        break;
+    }
+  }
+
+  void Assign(const IMENotification& aOther) {
+    bool changingMessage = mMessage != aOther.mMessage;
+    if (changingMessage) {
+      Clear();
+      mMessage = aOther.mMessage;
+    }
+    switch (mMessage) {
+      case NOTIFY_IME_OF_SELECTION_CHANGE:
+        if (changingMessage) {
+          mSelectionChangeData.mString = new nsString();
+        }
+        mSelectionChangeData.Assign(aOther.mSelectionChangeData);
+        break;
+      case NOTIFY_IME_OF_TEXT_CHANGE:
+        mTextChangeData = aOther.mTextChangeData;
+        break;
+      case NOTIFY_IME_OF_MOUSE_BUTTON_EVENT:
+        mMouseButtonEventData = aOther.mMouseButtonEventData;
+        break;
+      default:
+        break;
+    }
+  }
+
+  IMENotification& operator=(const IMENotification& aOther) {
+    Assign(aOther);
+    return *this;
+  }
+
+  void Clear() {
+    if (mMessage == NOTIFY_IME_OF_SELECTION_CHANGE) {
+      MOZ_ASSERT(mSelectionChangeData.mString);
+      delete mSelectionChangeData.mString;
+      mSelectionChangeData.mString = nullptr;
+    }
+    mMessage = NOTIFY_IME_OF_NOTHING;
+  }
+
+  bool HasNotification() const { return mMessage != NOTIFY_IME_OF_NOTHING; }
+
+  void MergeWith(const IMENotification& aNotification) {
+    switch (mMessage) {
+      case NOTIFY_IME_OF_NOTHING:
+        MOZ_ASSERT(aNotification.mMessage != NOTIFY_IME_OF_NOTHING);
+        Assign(aNotification);
+        break;
+      case NOTIFY_IME_OF_SELECTION_CHANGE:
+        MOZ_ASSERT(aNotification.mMessage == NOTIFY_IME_OF_SELECTION_CHANGE);
+        mSelectionChangeData.Assign(aNotification.mSelectionChangeData);
+        break;
+      case NOTIFY_IME_OF_TEXT_CHANGE:
+        MOZ_ASSERT(aNotification.mMessage == NOTIFY_IME_OF_TEXT_CHANGE);
+        mTextChangeData += aNotification.mTextChangeData;
+        break;
+      case NOTIFY_IME_OF_POSITION_CHANGE:
+      case NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED:
+        MOZ_ASSERT(aNotification.mMessage == mMessage);
+        break;
+      default:
+        MOZ_CRASH("Merging notification isn't supported");
+        break;
+    }
+  }
+
+  IMEMessage mMessage;
+
+  // NOTIFY_IME_OF_SELECTION_CHANGE specific data
+  struct SelectionChangeDataBase {
+    // Selection range.
+    uint32_t mOffset;
+
+    // Selected string
+    nsString* mString;
+
+    // Writing mode at the selection.
+    uint8_t mWritingModeBits;
+
+    bool mIsInitialized;
+    bool mHasRange;
+    bool mReversed;
+    bool mCausedByComposition;
+    bool mCausedBySelectionEvent;
+    bool mOccurredDuringComposition;
+
+    void SetWritingMode(const WritingMode& aWritingMode);
+    WritingMode GetWritingMode() const;
+
+    uint32_t StartOffset() const {
+      MOZ_ASSERT(mHasRange);
+      return mOffset;
+    }
+    uint32_t EndOffset() const {
+      MOZ_ASSERT(mHasRange);
+      return mOffset + Length();
+    }
+    uint32_t AnchorOffset() const {
+      MOZ_ASSERT(mHasRange);
+      return mOffset + (mReversed ? Length() : 0);
+    }
+    uint32_t FocusOffset() const {
+      MOZ_ASSERT(mHasRange);
+      return mOffset + (mReversed ? 0 : Length());
+    }
+    const nsString& String() const {
+      MOZ_ASSERT(mHasRange);
+      return *mString;
+    }
+    uint32_t Length() const {
+      MOZ_ASSERT(mHasRange);
+      return mString->Length();
+    }
+    bool IsInInt32Range() const {
+      return mHasRange && mOffset <= INT32_MAX && Length() <= INT32_MAX &&
+             mOffset + Length() <= INT32_MAX;
+    }
+    bool HasRange() const { return mIsInitialized && mHasRange; }
+    bool IsCollapsed() const { return !mHasRange || mString->IsEmpty(); }
+    void ClearSelectionData() {
+      mIsInitialized = false;
+      mHasRange = false;
+      mOffset = UINT32_MAX;
+      mString->Truncate();
+      mWritingModeBits = 0;
+      mReversed = false;
+    }
+    void Clear() {
+      ClearSelectionData();
+      mCausedByComposition = false;
+      mCausedBySelectionEvent = false;
+      mOccurredDuringComposition = false;
+    }
+    bool IsInitialized() const { return mIsInitialized; }
+    void Assign(const SelectionChangeDataBase& aOther) {
+      mIsInitialized = aOther.mIsInitialized;
+      mHasRange = aOther.mHasRange;
+      if (mIsInitialized && mHasRange) {
+        mOffset = aOther.mOffset;
+        *mString = aOther.String();
+        mReversed = aOther.mReversed;
+        mWritingModeBits = aOther.mWritingModeBits;
+      } else {
+        mOffset = UINT32_MAX;
+        mString->Truncate();
+        mReversed = false;
+        // Let's keep the writing mode for avoiding temporarily changing the
+        // writing mode at no selection range.
+      }
+      AssignReason(aOther.mCausedByComposition, aOther.mCausedBySelectionEvent,
+                   aOther.mOccurredDuringComposition);
+    }
+    void Assign(const WidgetQueryContentEvent& aQuerySelectedTextEvent);
+    void AssignReason(bool aCausedByComposition, bool aCausedBySelectionEvent,
+                      bool aOccurredDuringComposition) {
+      mCausedByComposition = aCausedByComposition;
+      mCausedBySelectionEvent = aCausedBySelectionEvent;
+      mOccurredDuringComposition = aOccurredDuringComposition;
+    }
+
+    bool EqualsRange(const SelectionChangeDataBase& aOther) const {
+      if (HasRange() != aOther.HasRange()) {
+        return false;
+      }
+      if (!HasRange()) {
+        return true;
+      }
+      return mOffset == aOther.mOffset && mString->Equals(*aOther.mString);
+    }
+    bool EqualsRangeAndDirection(const SelectionChangeDataBase& aOther) const {
+      return EqualsRange(aOther) &&
+             (!HasRange() || mReversed == aOther.mReversed);
+    }
+    bool EqualsRangeAndDirectionAndWritingMode(
+        const SelectionChangeDataBase& aOther) const {
+      return EqualsRangeAndDirection(aOther) &&
+             mWritingModeBits == aOther.mWritingModeBits;
+    }
+
+    bool EqualsRange(const ContentSelection& aContentSelection) const;
+    bool EqualsRangeAndWritingMode(
+        const ContentSelection& aContentSelection) const;
+
+    OffsetAndData<uint32_t> ToUint32OffsetAndData() const {
+      return OffsetAndData<uint32_t>(mOffset, *mString,
+                                     OffsetAndDataFor::SelectedString);
+    }
+  };
+
+  // SelectionChangeDataBase cannot have constructors because it's used in
+  // the union.  Therefore, SelectionChangeData should only implement
+  // constructors.  In other words, add other members to
+  // SelectionChangeDataBase.
+  struct SelectionChangeData final : public SelectionChangeDataBase {
+    SelectionChangeData() {
+      mString = &mStringInstance;
+      Clear();
+    }
+    explicit SelectionChangeData(const SelectionChangeDataBase& aOther) {
+      mString = &mStringInstance;
+      Assign(aOther);
+    }
+    SelectionChangeData(const SelectionChangeData& aOther) {
+      mString = &mStringInstance;
+      Assign(aOther);
+    }
+    SelectionChangeData& operator=(const SelectionChangeDataBase& aOther) {
+      mString = &mStringInstance;
+      Assign(aOther);
+      return *this;
+    }
+    SelectionChangeData& operator=(const SelectionChangeData& aOther) {
+      mString = &mStringInstance;
+      Assign(aOther);
+      return *this;
+    }
+
+   private:
+    // When SelectionChangeData is used outside of union, it shouldn't create
+    // nsString instance in the heap as far as possible.
+    nsString mStringInstance;
+  };
+
+  struct TextChangeDataBase {
+    // mStartOffset is the start offset of modified or removed text in
+    // original content and inserted text in new content.
+    uint32_t mStartOffset;
+    // mRemovalEndOffset is the end offset of modified or removed text in
+    // original content.  If the value is same as mStartOffset, no text hasn't
+    // been removed yet.
+    uint32_t mRemovedEndOffset;
+    // mAddedEndOffset is the end offset of inserted text or same as
+    // mStartOffset if just removed.  The vlaue is offset in the new content.
+    uint32_t mAddedEndOffset;
+
+    // Note that TextChangeDataBase may be the result of merging two or more
+    // changes especially in e10s mode.
+
+    // mCausedOnlyByComposition is true only when *all* merged changes are
+    // caused by composition.
+    bool mCausedOnlyByComposition;
+    // mIncludingChangesDuringComposition is true if at least one change which
+    // is not caused by composition occurred during the last composition.
+    // Note that if after the last composition is finished and there are some
+    // changes not caused by composition, this is set to false.
+    bool mIncludingChangesDuringComposition;
+    // mIncludingChangesWithoutComposition is true if there is at least one
+    // change which did occur when there wasn't a composition ongoing.
+    bool mIncludingChangesWithoutComposition;
+
+    uint32_t OldLength() const {
+      MOZ_ASSERT(IsValid());
+      return mRemovedEndOffset - mStartOffset;
+    }
+    uint32_t NewLength() const {
+      MOZ_ASSERT(IsValid());
+      return mAddedEndOffset - mStartOffset;
+    }
+
+    // Positive if text is added. Negative if text is removed.
+    int64_t Difference() const { return mAddedEndOffset - mRemovedEndOffset; }
+
+    bool IsInInt32Range() const {
+      MOZ_ASSERT(IsValid());
+      return mStartOffset <= INT32_MAX && mRemovedEndOffset <= INT32_MAX &&
+             mAddedEndOffset <= INT32_MAX;
+    }
+
+    bool IsValid() const {
+      return !(mStartOffset == UINT32_MAX && !mRemovedEndOffset &&
+               !mAddedEndOffset);
+    }
+
+    void Clear() {
+      mStartOffset = UINT32_MAX;
+      mRemovedEndOffset = mAddedEndOffset = 0;
+    }
+
+    void MergeWith(const TextChangeDataBase& aOther);
+    TextChangeDataBase& operator+=(const TextChangeDataBase& aOther) {
+      MergeWith(aOther);
+      return *this;
+    }
+
+#ifdef DEBUG
+    void Test();
+#endif  // #ifdef DEBUG
+  };
+
+  // TextChangeDataBase cannot have constructors because they are used in union.
+  // Therefore, TextChangeData should only implement constructor.  In other
+  // words, add other members to TextChangeDataBase.
+  struct TextChangeData : public TextChangeDataBase {
+    TextChangeData() { Clear(); }
+
+    TextChangeData(uint32_t aStartOffset, uint32_t aRemovedEndOffset,
+                   uint32_t aAddedEndOffset, bool aCausedByComposition,
+                   bool aOccurredDuringComposition) {
+      MOZ_ASSERT(aRemovedEndOffset >= aStartOffset,
+                 "removed end offset must not be smaller than start offset");
+      MOZ_ASSERT(aAddedEndOffset >= aStartOffset,
+                 "added end offset must not be smaller than start offset");
+      mStartOffset = aStartOffset;
+      mRemovedEndOffset = aRemovedEndOffset;
+      mAddedEndOffset = aAddedEndOffset;
+      mCausedOnlyByComposition = aCausedByComposition;
+      mIncludingChangesDuringComposition =
+          !aCausedByComposition && aOccurredDuringComposition;
+      mIncludingChangesWithoutComposition =
+          !aCausedByComposition && !aOccurredDuringComposition;
+    }
+  };
+
+  struct MouseButtonEventData {
+    // The value of WidgetEvent::mMessage
+    EventMessage mEventMessage;
+    // Character offset from the start of the focused editor under the cursor
+    uint32_t mOffset;
+    // Cursor position in pixels relative to the widget
+    LayoutDeviceIntPoint mCursorPos;
+    // Character rect in pixels under the cursor relative to the widget
+    LayoutDeviceIntRect mCharRect;
+    // The value of WidgetMouseEventBase::button and buttons
+    int16_t mButton;
+    int16_t mButtons;
+    // The value of WidgetInputEvent::modifiers
+    Modifiers mModifiers;
+  };
+
+  union {
+    // NOTIFY_IME_OF_SELECTION_CHANGE specific data
+    SelectionChangeDataBase mSelectionChangeData;
+
+    // NOTIFY_IME_OF_TEXT_CHANGE specific data
+    TextChangeDataBase mTextChangeData;
+
+    // NOTIFY_IME_OF_MOUSE_BUTTON_EVENT specific data
+    MouseButtonEventData mMouseButtonEventData;
+  };
+
+  void SetData(const SelectionChangeDataBase& aSelectionChangeData) {
+    MOZ_RELEASE_ASSERT(mMessage == NOTIFY_IME_OF_SELECTION_CHANGE);
+    mSelectionChangeData.Assign(aSelectionChangeData);
+  }
+
+  void SetData(const TextChangeDataBase& aTextChangeData) {
+    MOZ_RELEASE_ASSERT(mMessage == NOTIFY_IME_OF_TEXT_CHANGE);
+    mTextChangeData = aTextChangeData;
+  }
+};
+
+struct CandidateWindowPosition {
+  // Upper left corner of the candidate window if mExcludeRect is false.
+  // Otherwise, the position currently interested.  E.g., caret position.
+  LayoutDeviceIntPoint mPoint;
+  // Rect which shouldn't be overlapped with the candidate window.
+  // This is valid only when mExcludeRect is true.
+  LayoutDeviceIntRect mRect;
+  // See explanation of mPoint and mRect.
+  bool mExcludeRect;
+};
+
+std::ostream& operator<<(std::ostream& aStream, const IMEEnabled& aEnabled);
+std::ostream& operator<<(std::ostream& aStream, const IMEState::Open& aOpen);
+std::ostream& operator<<(std::ostream& aStream, const IMEState& aState);
+std::ostream& operator<<(std::ostream& aStream,
+                         const InputContext::Origin& aOrigin);
+std::ostream& operator<<(std::ostream& aStream, const InputContext& aContext);
+std::ostream& operator<<(std::ostream& aStream,
+                         const InputContextAction::Cause& aCause);
+std::ostream& operator<<(std::ostream& aStream,
+                         const InputContextAction::FocusChange& aFocusChange);
+std::ostream& operator<<(std::ostream& aStream,
+                         const IMENotification::SelectionChangeDataBase& aData);
+std::ostream& operator<<(std::ostream& aStream,
+                         const IMENotification::TextChangeDataBase& aData);
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // #ifndef mozilla_widget_IMEData_h_
diff --git a/widget/IconLoader.cpp b/widget/IconLoader.cpp
new file mode 100644
index 0000000000..5c0488e3e2
--- /dev/null
+++ b/widget/IconLoader.cpp
@@ -0,0 +1,132 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/widget/IconLoader.h"
+#include "gfxPlatform.h"
+#include "imgIContainer.h"
+#include "imgLoader.h"
+#include "imgRequestProxy.h"
+#include "mozilla/dom/Document.h"
+#include "nsContentUtils.h"
+#include "nsIContent.h"
+#include "nsIContentPolicy.h"
+
+using namespace mozilla;
+
+namespace mozilla::widget {
+
+NS_IMPL_ISUPPORTS(IconLoader, imgINotificationObserver)
+
+IconLoader::IconLoader(Listener* aListener) : mListener(aListener) {}
+
+IconLoader::~IconLoader() { Destroy(); }
+
+void IconLoader::Destroy() {
+  if (mIconRequest) {
+    mIconRequest->CancelAndForgetObserver(NS_BINDING_ABORTED);
+    mIconRequest = nullptr;
+  }
+  mListener = nullptr;
+}
+
+nsresult IconLoader::LoadIcon(nsIURI* aIconURI, nsINode* aNode,
+                              bool aIsInternalIcon) {
+  if (mIconRequest) {
+    // Another icon request is already in flight.  Kill it.
+    mIconRequest->CancelWithReason(
+        NS_BINDING_ABORTED, "Another icon request is already in flight"_ns);
+    mIconRequest = nullptr;
+  }
+
+  if (!aNode) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<mozilla::dom::Document> document = aNode->OwnerDoc();
+
+  nsCOMPtr<nsILoadGroup> loadGroup = document->GetDocumentLoadGroup();
+  if (!loadGroup) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<imgLoader> loader = nsContentUtils::GetImgLoaderForDocument(document);
+  if (!loader) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult rv;
+  if (aIsInternalIcon) {
+    rv = loader->LoadImage(
+        aIconURI, nullptr, nullptr, nullptr, 0, loadGroup, this, nullptr,
+        nullptr, nsIRequest::LOAD_NORMAL, nullptr,
+        nsIContentPolicy::TYPE_INTERNAL_IMAGE, u""_ns,
+        /* aUseUrgentStartForChannel */ false, /* aLinkPreload */ false, 0,
+        getter_AddRefs(mIconRequest));
+  } else {
+    // TODO: nsIContentPolicy::TYPE_INTERNAL_IMAGE may not be the correct
+    // policy. See bug 1691868 for more details.
+    rv = loader->LoadImage(
+        aIconURI, nullptr, nullptr, aNode->NodePrincipal(), 0, loadGroup, this,
+        aNode, document, nsIRequest::LOAD_NORMAL, nullptr,
+        nsIContentPolicy::TYPE_INTERNAL_IMAGE, u""_ns,
+        /* aUseUrgentStartForChannel */ false,
+        /* aLinkPreload */ false, 0, getter_AddRefs(mIconRequest));
+  }
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+//
+// imgINotificationObserver
+//
+
+void IconLoader::Notify(imgIRequest* aRequest, int32_t aType,
+                        const nsIntRect* aData) {
+  if (aType == imgINotificationObserver::LOAD_COMPLETE) {
+    // Make sure the image loaded successfully.
+    uint32_t status = imgIRequest::STATUS_ERROR;
+    if (NS_FAILED(aRequest->GetImageStatus(&status)) ||
+        (status & imgIRequest::STATUS_ERROR)) {
+      mIconRequest->CancelWithReason(NS_BINDING_ABORTED,
+                                     "GetImageStatus failed"_ns);
+      mIconRequest = nullptr;
+      return;
+    }
+
+    nsCOMPtr<imgIContainer> image;
+    aRequest->GetImage(getter_AddRefs(image));
+    MOZ_ASSERT(image);
+
+    // Ask the image to decode at its intrinsic size.
+    int32_t width = 0, height = 0;
+    image->GetWidth(&width);
+    image->GetHeight(&height);
+    image->RequestDecodeForSize(nsIntSize(width, height),
+                                imgIContainer::FLAG_HIGH_QUALITY_SCALING);
+  }
+
+  if (aType == imgINotificationObserver::FRAME_COMPLETE) {
+    nsCOMPtr<imgIContainer> image;
+    aRequest->GetImage(getter_AddRefs(image));
+    MOZ_ASSERT(image);
+
+    if (mListener) {
+      mListener->OnComplete(image);
+    }
+    return;
+  }
+
+  if (aType == imgINotificationObserver::DECODE_COMPLETE) {
+    if (mIconRequest && mIconRequest == aRequest) {
+      mIconRequest->CancelWithReason(NS_BINDING_ABORTED, "DECODE_COMPLETE"_ns);
+      mIconRequest = nullptr;
+    }
+  }
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/IconLoader.h b/widget/IconLoader.h
new file mode 100644
index 0000000000..f665df6fc5
--- /dev/null
+++ b/widget/IconLoader.h
@@ -0,0 +1,69 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_IconLoader_h_
+#define mozilla_widget_IconLoader_h_
+
+#include "imgINotificationObserver.h"
+#include "mozilla/RefPtr.h"
+#include "nsCOMPtr.h"
+#include "nsISupports.h"
+
+class nsIURI;
+class nsINode;
+class imgRequestProxy;
+class imgIContainer;
+
+namespace mozilla::widget {
+
+/**
+ * IconLoader is a utility for loading icons from either the disk or over
+ * the network, and then using them in native OS widgetry like the macOS
+ * global menu bar or the Windows notification area.
+ */
+
+class IconLoader : public imgINotificationObserver {
+ public:
+  // This is the interface that our listeners need to implement so that they can
+  // be notified when the icon is loaded.
+  class Listener {
+   public:
+    virtual nsresult OnComplete(imgIContainer* aContainer) = 0;
+  };
+
+  // Create the loader.
+  // aListener will be notified when the load is complete.
+  // The loader does not keep an owning reference to the listener. Call Destroy
+  // before the listener goes away.
+  explicit IconLoader(Listener* aListener);
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_IMGINOTIFICATIONOBSERVER
+
+  // LoadIcon will start a load request for the icon.
+  // The request may not complete until after LoadIcon returns.
+  // If aIsInternalIcon is true, the document and principal will not be
+  // used when loading.
+  nsresult LoadIcon(nsIURI* aIconURI, nsINode* aNode,
+                    bool aIsInternalIcon = false);
+
+  void Destroy();
+
+ protected:
+  virtual ~IconLoader();
+
+ private:
+  RefPtr<imgRequestProxy> mIconRequest;
+
+  // The listener, which is notified when loading completes.
+  // Can be null, after a call to Destroy.
+  // This is a non-owning reference and needs to be cleared with a call to
+  // Destroy before the listener goes away.
+  Listener* mListener;
+};
+
+}  // namespace mozilla::widget
+#endif  // mozilla_widget_IconLoader_h_
diff --git a/widget/InProcessCompositorWidget.cpp b/widget/InProcessCompositorWidget.cpp
new file mode 100644
index 0000000000..1c25e9d9a1
--- /dev/null
+++ b/widget/InProcessCompositorWidget.cpp
@@ -0,0 +1,136 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "InProcessCompositorWidget.h"
+
+#include "mozilla/VsyncDispatcher.h"
+#include "nsBaseWidget.h"
+
+namespace mozilla {
+namespace widget {
+
+// Platforms with no OOP compositor process support use
+// InProcessCompositorWidget by default.
+#if !defined(MOZ_WIDGET_SUPPORTS_OOP_COMPOSITING)
+/* static */
+RefPtr<CompositorWidget> CompositorWidget::CreateLocal(
+    const CompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions, nsIWidget* aWidget) {
+  // We're getting crashes from storing a NULL mWidget, and this is the
+  // only remaining explanation that doesn't involve memory corruption,
+  // so placing a release assert here. For even more sanity-checking, we
+  // do it after the static_cast.
+  nsBaseWidget* widget = static_cast<nsBaseWidget*>(aWidget);
+  MOZ_RELEASE_ASSERT(widget);
+  return new InProcessCompositorWidget(aOptions, widget);
+}
+#endif
+
+InProcessCompositorWidget::InProcessCompositorWidget(
+    const layers::CompositorOptions& aOptions, nsBaseWidget* aWidget)
+    : CompositorWidget(aOptions),
+      mWidget(aWidget),
+      mCanary(CANARY_VALUE),
+      mWidgetSanity(aWidget) {
+  // The only method of construction that is used outside of unit tests is
+  // ::CreateLocal, above. That method of construction asserts that mWidget
+  // is not assigned a NULL value. And yet mWidget is NULL in some crash
+  // reports that involve other class methods. Adding a release assert here
+  // will give us the earliest possible notification that we're headed for
+  // a crash.
+  MOZ_RELEASE_ASSERT(mWidget);
+}
+
+bool InProcessCompositorWidget::PreRender(WidgetRenderingContext* aContext) {
+  CheckWidgetSanity();
+  return mWidget->PreRender(aContext);
+}
+
+void InProcessCompositorWidget::PostRender(WidgetRenderingContext* aContext) {
+  CheckWidgetSanity();
+  mWidget->PostRender(aContext);
+}
+
+RefPtr<layers::NativeLayerRoot>
+InProcessCompositorWidget::GetNativeLayerRoot() {
+  CheckWidgetSanity();
+  return mWidget->GetNativeLayerRoot();
+}
+
+already_AddRefed<gfx::DrawTarget>
+InProcessCompositorWidget::StartRemoteDrawing() {
+  CheckWidgetSanity();
+  return mWidget->StartRemoteDrawing();
+}
+
+already_AddRefed<gfx::DrawTarget>
+InProcessCompositorWidget::StartRemoteDrawingInRegion(
+    const LayoutDeviceIntRegion& aInvalidRegion,
+    layers::BufferMode* aBufferMode) {
+  CheckWidgetSanity();
+  return mWidget->StartRemoteDrawingInRegion(aInvalidRegion, aBufferMode);
+}
+
+void InProcessCompositorWidget::EndRemoteDrawing() {
+  CheckWidgetSanity();
+  mWidget->EndRemoteDrawing();
+}
+
+void InProcessCompositorWidget::EndRemoteDrawingInRegion(
+    gfx::DrawTarget* aDrawTarget, const LayoutDeviceIntRegion& aInvalidRegion) {
+  CheckWidgetSanity();
+  mWidget->EndRemoteDrawingInRegion(aDrawTarget, aInvalidRegion);
+}
+
+void InProcessCompositorWidget::CleanupRemoteDrawing() {
+  CheckWidgetSanity();
+  mWidget->CleanupRemoteDrawing();
+}
+
+void InProcessCompositorWidget::CleanupWindowEffects() {
+  CheckWidgetSanity();
+  mWidget->CleanupWindowEffects();
+}
+
+bool InProcessCompositorWidget::InitCompositor(
+    layers::Compositor* aCompositor) {
+  CheckWidgetSanity();
+  return mWidget->InitCompositor(aCompositor);
+}
+
+LayoutDeviceIntSize InProcessCompositorWidget::GetClientSize() {
+  CheckWidgetSanity();
+  return mWidget->GetClientSize();
+}
+
+uint32_t InProcessCompositorWidget::GetGLFrameBufferFormat() {
+  CheckWidgetSanity();
+  return mWidget->GetGLFrameBufferFormat();
+}
+
+uintptr_t InProcessCompositorWidget::GetWidgetKey() {
+  CheckWidgetSanity();
+  return reinterpret_cast<uintptr_t>(mWidget);
+}
+
+nsIWidget* InProcessCompositorWidget::RealWidget() { return mWidget; }
+
+void InProcessCompositorWidget::ObserveVsync(VsyncObserver* aObserver) {
+  CheckWidgetSanity();
+  if (RefPtr<CompositorVsyncDispatcher> cvd =
+          mWidget->GetCompositorVsyncDispatcher()) {
+    cvd->SetCompositorVsyncObserver(aObserver);
+  }
+}
+
+const char* InProcessCompositorWidget::CANARY_VALUE =
+    reinterpret_cast<char*>(0x1a1a1a1a);
+
+void InProcessCompositorWidget::CheckWidgetSanity() {
+  MOZ_RELEASE_ASSERT(mWidgetSanity == mWidget);
+  MOZ_RELEASE_ASSERT(mCanary == CANARY_VALUE);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/InProcessCompositorWidget.h b/widget/InProcessCompositorWidget.h
new file mode 100644
index 0000000000..eb44668de9
--- /dev/null
+++ b/widget/InProcessCompositorWidget.h
@@ -0,0 +1,55 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_InProcessCompositorWidget_h__
+#define mozilla_widget_InProcessCompositorWidget_h__
+
+#include "CompositorWidget.h"
+
+namespace mozilla {
+namespace widget {
+
+// This version of CompositorWidget implements a wrapper around
+// nsBaseWidget.
+class InProcessCompositorWidget : public CompositorWidget {
+ public:
+  explicit InProcessCompositorWidget(const layers::CompositorOptions& aOptions,
+                                     nsBaseWidget* aWidget);
+
+  virtual bool PreRender(WidgetRenderingContext* aManager) override;
+  virtual void PostRender(WidgetRenderingContext* aManager) override;
+  virtual RefPtr<layers::NativeLayerRoot> GetNativeLayerRoot() override;
+  virtual already_AddRefed<gfx::DrawTarget> StartRemoteDrawing() override;
+  virtual already_AddRefed<gfx::DrawTarget> StartRemoteDrawingInRegion(
+      const LayoutDeviceIntRegion& aInvalidRegion,
+      layers::BufferMode* aBufferMode) override;
+  virtual void EndRemoteDrawing() override;
+  virtual void EndRemoteDrawingInRegion(
+      gfx::DrawTarget* aDrawTarget,
+      const LayoutDeviceIntRegion& aInvalidRegion) override;
+  virtual void CleanupRemoteDrawing() override;
+  virtual void CleanupWindowEffects() override;
+  virtual bool InitCompositor(layers::Compositor* aCompositor) override;
+  virtual LayoutDeviceIntSize GetClientSize() override;
+  virtual uint32_t GetGLFrameBufferFormat() override;
+  virtual void ObserveVsync(VsyncObserver* aObserver) override;
+  virtual uintptr_t GetWidgetKey() override;
+
+  // If you can override this method, inherit from CompositorWidget instead.
+  nsIWidget* RealWidget() override;
+
+ protected:
+  nsBaseWidget* mWidget;
+  // Bug 1679368: Maintain an additional widget pointer, constant, and
+  // function for sanity checking while we chase a crash.
+  static const char* CANARY_VALUE;
+  const char* mCanary;
+  nsBaseWidget* mWidgetSanity;
+  void CheckWidgetSanity();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/InitData.h b/widget/InitData.h
new file mode 100644
index 0000000000..1498feed9a
--- /dev/null
+++ b/widget/InitData.h
@@ -0,0 +1,113 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_InitData_h__
+#define mozilla_widget_InitData_h__
+
+#include <cstdint>
+#include "mozilla/TypedEnumBits.h"
+#include "X11UndefineNone.h"
+
+namespace mozilla::widget {
+
+// Window types
+enum class WindowType : uint8_t {
+  TopLevel,   // default top level window
+  Dialog,     // top level window but usually handled differently
+              // by the OS
+  Sheet,      // MacOSX sheet (special dialog class)
+  Popup,      // used for combo boxes, etc
+  Child,      // child windows (contained inside a window on the
+              // desktop (has no border))
+  Invisible,  // windows that are invisible or offscreen
+};
+
+// Popup types for WindowType::Popup
+enum class PopupType : uint8_t {
+  Panel,
+  Menu,
+  Tooltip,
+  Any,  // used only to pass to nsXULPopupManager::GetTopPopup
+};
+
+// Popup levels specify the window ordering behaviour.
+enum class PopupLevel : uint8_t {
+  // The popup appears just above its parent and maintains its position
+  // relative to the parent.
+  Parent,
+  // The popup is a floating popup used for tool palettes. A parent window must
+  // be specified, but a platform implementation need not use this. On Windows,
+  // floating is generally equivalent to parent. On Mac, floating puts the
+  // popup at toplevel, but it will hide when the application is deactivated.
+  Floating,
+  // The popup appears on top of other windows, including those of other
+  // applications.
+  Top,
+};
+
+// Border styles
+enum class BorderStyle : int16_t {
+  None = 0,           // no border, titlebar, etc.. opposite of all
+  All = 1 << 0,       // all window decorations
+  Border = 1 << 1,    // enables the border on the window. these
+                      // are only for decoration and are not
+                      // resize handles
+  ResizeH = 1 << 2,   // enables the resize handles for the
+                      // window. if this is set, border is
+                      // implied to also be set
+  Title = 1 << 3,     // enables the titlebar for the window
+  Menu = 1 << 4,      // enables the window menu button on the
+                      // title bar. this being on should force
+                      // the title bar to display
+  Minimize = 1 << 5,  // enables the minimize button so the user
+                      // can minimize the window. turned off for
+                      // tranient windows since they can not be
+                      // minimized separate from their parent
+  Maximize = 1 << 6,  // enables the maxmize button so the user
+                      // can maximize the window
+  Close = 1 << 7,     // show the close button
+  Default = -1        // whatever the OS wants... i.e. don't do anything
+};
+
+MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(BorderStyle)
+
+enum class TransparencyMode : uint8_t {
+  Opaque = 0,   // Fully opaque
+  Transparent,  // Parts of the window may be transparent
+  // If you add to the end here, you must update the serialization code in
+  // WidgetMessageUtils.h
+};
+
+// Basic struct for widget initialization data.
+// @see Create member function of nsIWidget
+struct InitData {
+  WindowType mWindowType = WindowType::Child;
+  BorderStyle mBorderStyle = BorderStyle::Default;
+  PopupType mPopupHint = PopupType::Panel;
+  PopupLevel mPopupLevel = PopupLevel::Top;
+  TransparencyMode mTransparencyMode = TransparencyMode::Opaque;
+  // when painting exclude area occupied by child windows and sibling windows
+  bool mClipChildren = false;
+  bool mClipSiblings = false;
+  bool mRTL = false;
+  bool mNoAutoHide = false;   // true for noautohide panels
+  bool mIsDragPopup = false;  // true for drag feedback panels
+  // true if window creation animation is suppressed, e.g. for session restore
+  bool mIsAnimationSuppressed = false;
+  // true if the window should support an alpha channel, if available.
+  bool mHasRemoteContent = false;
+  bool mAlwaysOnTop = false;
+  // Whether we're a PictureInPicture window
+  bool mPIPWindow = false;
+  // True if the window is user-resizable.
+  bool mResizable = false;
+  bool mIsPrivate = false;
+  // True if the window is an alert / notification.
+  bool mIsAlert = false;
+};
+
+}  // namespace mozilla::widget
+
+#endif  // mozilla_widget_InitData
diff --git a/widget/InputData.cpp b/widget/InputData.cpp
new file mode 100644
index 0000000000..3d1695dd8e
--- /dev/null
+++ b/widget/InputData.cpp
@@ -0,0 +1,924 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "InputData.h"
+
+#include "mozilla/dom/MouseEventBinding.h"
+#include "mozilla/dom/Touch.h"
+#include "mozilla/dom/WheelEventBinding.h"
+#include "mozilla/TextEvents.h"
+#include "nsContentUtils.h"
+#include "nsDebug.h"
+#include "nsThreadUtils.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/TouchEvents.h"
+#include "mozilla/SwipeTracker.h"
+#include "UnitTransforms.h"
+
+namespace mozilla {
+
+using namespace dom;
+
+InputData::~InputData() = default;
+
+InputData::InputData(InputType aInputType)
+    : mInputType(aInputType),
+      mFocusSequenceNumber(0),
+      mLayersId{0},
+      modifiers(0) {}
+
+InputData::InputData(InputType aInputType, TimeStamp aTimeStamp,
+                     Modifiers aModifiers)
+    : mInputType(aInputType),
+      mTimeStamp(aTimeStamp),
+      mFocusSequenceNumber(0),
+      mLayersId{0},
+      modifiers(aModifiers) {}
+
+SingleTouchData::SingleTouchData(int32_t aIdentifier,
+                                 ScreenIntPoint aScreenPoint,
+                                 ScreenSize aRadius, float aRotationAngle,
+                                 float aForce)
+    : mIdentifier(aIdentifier),
+      mScreenPoint(aScreenPoint),
+      mRadius(aRadius),
+      mRotationAngle(aRotationAngle),
+      mForce(aForce) {}
+
+SingleTouchData::SingleTouchData(int32_t aIdentifier,
+                                 ParentLayerPoint aLocalScreenPoint,
+                                 ScreenSize aRadius, float aRotationAngle,
+                                 float aForce)
+    : mIdentifier(aIdentifier),
+      mLocalScreenPoint(aLocalScreenPoint),
+      mRadius(aRadius),
+      mRotationAngle(aRotationAngle),
+      mForce(aForce) {}
+
+SingleTouchData::SingleTouchData()
+    : mIdentifier(0), mRotationAngle(0.0), mForce(0.0) {}
+
+already_AddRefed<Touch> SingleTouchData::ToNewDOMTouch() const {
+  MOZ_ASSERT(NS_IsMainThread(),
+             "Can only create dom::Touch instances on main thread");
+  RefPtr<Touch> touch =
+      new Touch(mIdentifier,
+                LayoutDeviceIntPoint::Truncate(mScreenPoint.x, mScreenPoint.y),
+                LayoutDeviceIntPoint::Truncate(mRadius.width, mRadius.height),
+                mRotationAngle, mForce);
+  touch->tiltX = mTiltX;
+  touch->tiltY = mTiltY;
+  touch->twist = mTwist;
+  return touch.forget();
+}
+
+MultiTouchInput::MultiTouchInput(MultiTouchType aType, uint32_t aTime,
+                                 TimeStamp aTimeStamp, Modifiers aModifiers)
+    : InputData(MULTITOUCH_INPUT, aTimeStamp, aModifiers),
+      mType(aType),
+      mHandledByAPZ(false) {}
+
+MultiTouchInput::MultiTouchInput()
+    : InputData(MULTITOUCH_INPUT),
+      mType(MULTITOUCH_START),
+      mHandledByAPZ(false) {}
+
+MultiTouchInput::MultiTouchInput(const WidgetTouchEvent& aTouchEvent)
+    : InputData(MULTITOUCH_INPUT, aTouchEvent.mTimeStamp,
+                aTouchEvent.mModifiers),
+      mHandledByAPZ(aTouchEvent.mFlags.mHandledByAPZ),
+      mButton(aTouchEvent.mButton),
+      mButtons(aTouchEvent.mButtons) {
+  MOZ_ASSERT(NS_IsMainThread(),
+             "Can only copy from WidgetTouchEvent on main thread");
+
+  switch (aTouchEvent.mMessage) {
+    case eTouchStart:
+      mType = MULTITOUCH_START;
+      break;
+    case eTouchMove:
+      mType = MULTITOUCH_MOVE;
+      break;
+    case eTouchEnd:
+      mType = MULTITOUCH_END;
+      break;
+    case eTouchCancel:
+      mType = MULTITOUCH_CANCEL;
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE("Did not assign a type to a MultiTouchInput");
+      break;
+  }
+
+  mScreenOffset = ViewAs<ExternalPixel>(
+      aTouchEvent.mWidget->WidgetToScreenOffset(),
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+
+  for (size_t i = 0; i < aTouchEvent.mTouches.Length(); i++) {
+    const Touch* domTouch = aTouchEvent.mTouches[i];
+
+    // Extract data from weird interfaces.
+    int32_t identifier = domTouch->Identifier();
+    int32_t radiusX = domTouch->RadiusX(CallerType::System);
+    int32_t radiusY = domTouch->RadiusY(CallerType::System);
+    float rotationAngle = domTouch->RotationAngle(CallerType::System);
+    float force = domTouch->Force(CallerType::System);
+
+    SingleTouchData data(
+        identifier,
+        ViewAs<ScreenPixel>(
+            domTouch->mRefPoint,
+            PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent),
+        ScreenSize((float)radiusX, (float)radiusY), rotationAngle, force);
+
+    mTouches.AppendElement(data);
+  }
+}
+
+void MultiTouchInput::Translate(const ScreenPoint& aTranslation) {
+  ScreenIntPoint translation = RoundedToInt(aTranslation);
+
+  for (auto& touchData : mTouches) {
+    for (auto& historicalData : touchData.mHistoricalData) {
+      historicalData.mScreenPoint.MoveBy(translation.x, translation.y);
+    }
+    touchData.mScreenPoint.MoveBy(translation.x, translation.y);
+  }
+}
+
+WidgetTouchEvent MultiTouchInput::ToWidgetEvent(nsIWidget* aWidget,
+                                                uint16_t aInputSource) const {
+  MOZ_ASSERT(NS_IsMainThread(),
+             "Can only convert To WidgetTouchEvent on main thread");
+  MOZ_ASSERT(aInputSource ==
+                 mozilla::dom::MouseEvent_Binding::MOZ_SOURCE_TOUCH ||
+             aInputSource == mozilla::dom::MouseEvent_Binding::MOZ_SOURCE_PEN);
+
+  EventMessage touchEventMessage = eVoidEvent;
+  switch (mType) {
+    case MULTITOUCH_START:
+      touchEventMessage = eTouchStart;
+      break;
+    case MULTITOUCH_MOVE:
+      touchEventMessage = eTouchMove;
+      break;
+    case MULTITOUCH_END:
+      touchEventMessage = eTouchEnd;
+      break;
+    case MULTITOUCH_CANCEL:
+      touchEventMessage = eTouchCancel;
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE(
+          "Did not assign a type to WidgetTouchEvent in MultiTouchInput");
+      break;
+  }
+
+  WidgetTouchEvent event(true, touchEventMessage, aWidget);
+  if (touchEventMessage == eVoidEvent) {
+    return event;
+  }
+
+  event.mModifiers = this->modifiers;
+  event.mTimeStamp = this->mTimeStamp;
+  event.mFlags.mHandledByAPZ = mHandledByAPZ;
+  event.mFocusSequenceNumber = mFocusSequenceNumber;
+  event.mLayersId = mLayersId;
+  event.mInputSource = aInputSource;
+  event.mButton = mButton;
+  event.mButtons = mButtons;
+
+  for (size_t i = 0; i < mTouches.Length(); i++) {
+    *event.mTouches.AppendElement() = mTouches[i].ToNewDOMTouch();
+  }
+
+  return event;
+}
+
+int32_t MultiTouchInput::IndexOfTouch(int32_t aTouchIdentifier) {
+  for (size_t i = 0; i < mTouches.Length(); i++) {
+    if (mTouches[i].mIdentifier == aTouchIdentifier) {
+      return (int32_t)i;
+    }
+  }
+  return -1;
+}
+
+bool MultiTouchInput::TransformToLocal(
+    const ScreenToParentLayerMatrix4x4& aTransform) {
+  for (auto& touchData : mTouches) {
+    for (auto& historicalData : touchData.mHistoricalData) {
+      Maybe<ParentLayerIntPoint> historicalPoint =
+          UntransformBy(aTransform, historicalData.mScreenPoint);
+      if (!historicalPoint) {
+        return false;
+      }
+      historicalData.mLocalScreenPoint = *historicalPoint;
+    }
+    Maybe<ParentLayerIntPoint> point =
+        UntransformBy(aTransform, touchData.mScreenPoint);
+    if (!point) {
+      return false;
+    }
+    touchData.mLocalScreenPoint = *point;
+  }
+  return true;
+}
+
+MouseInput::MouseInput()
+    : InputData(MOUSE_INPUT),
+      mType(MOUSE_NONE),
+      mButtonType(NONE),
+      mInputSource(0),
+      mButtons(0),
+      mHandledByAPZ(false),
+      mPreventClickEvent(false) {}
+
+MouseInput::MouseInput(MouseType aType, ButtonType aButtonType,
+                       uint16_t aInputSource, int16_t aButtons,
+                       const ScreenPoint& aPoint, TimeStamp aTimeStamp,
+                       Modifiers aModifiers)
+    : InputData(MOUSE_INPUT, aTimeStamp, aModifiers),
+      mType(aType),
+      mButtonType(aButtonType),
+      mInputSource(aInputSource),
+      mButtons(aButtons),
+      mOrigin(aPoint),
+      mHandledByAPZ(false),
+      mPreventClickEvent(false) {}
+
+MouseInput::MouseInput(const WidgetMouseEventBase& aMouseEvent)
+    : InputData(MOUSE_INPUT, aMouseEvent.mTimeStamp, aMouseEvent.mModifiers),
+      mType(MOUSE_NONE),
+      mButtonType(NONE),
+      mInputSource(aMouseEvent.mInputSource),
+      mButtons(aMouseEvent.mButtons),
+      mHandledByAPZ(aMouseEvent.mFlags.mHandledByAPZ),
+      mPreventClickEvent(aMouseEvent.mClass == eMouseEventClass &&
+                         aMouseEvent.AsMouseEvent()->mClickEventPrevented) {
+  MOZ_ASSERT(NS_IsMainThread(),
+             "Can only copy from WidgetTouchEvent on main thread");
+
+  mButtonType = NONE;
+
+  switch (aMouseEvent.mButton) {
+    case MouseButton::ePrimary:
+      mButtonType = MouseInput::PRIMARY_BUTTON;
+      break;
+    case MouseButton::eMiddle:
+      mButtonType = MouseInput::MIDDLE_BUTTON;
+      break;
+    case MouseButton::eSecondary:
+      mButtonType = MouseInput::SECONDARY_BUTTON;
+      break;
+  }
+
+  switch (aMouseEvent.mMessage) {
+    case eMouseMove:
+      mType = MOUSE_MOVE;
+      break;
+    case eMouseUp:
+      mType = MOUSE_UP;
+      break;
+    case eMouseDown:
+      mType = MOUSE_DOWN;
+      break;
+    case eDragStart:
+      mType = MOUSE_DRAG_START;
+      break;
+    case eDragEnd:
+      mType = MOUSE_DRAG_END;
+      break;
+    case eMouseEnterIntoWidget:
+      mType = MOUSE_WIDGET_ENTER;
+      break;
+    case eMouseExitFromWidget:
+      mType = MOUSE_WIDGET_EXIT;
+      break;
+    case eMouseExploreByTouch:
+      mType = MOUSE_EXPLORE_BY_TOUCH;
+      break;
+    case eMouseHitTest:
+      mType = MOUSE_HITTEST;
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE("Mouse event type not supported");
+      break;
+  }
+
+  mOrigin = ScreenPoint(ViewAs<ScreenPixel>(
+      aMouseEvent.mRefPoint,
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent));
+}
+
+bool MouseInput::IsLeftButton() const { return mButtonType == PRIMARY_BUTTON; }
+
+bool MouseInput::TransformToLocal(
+    const ScreenToParentLayerMatrix4x4& aTransform) {
+  Maybe<ParentLayerPoint> point = UntransformBy(aTransform, mOrigin);
+  if (!point) {
+    return false;
+  }
+  mLocalOrigin = *point;
+
+  return true;
+}
+
+WidgetMouseEvent MouseInput::ToWidgetEvent(nsIWidget* aWidget) const {
+  MOZ_ASSERT(NS_IsMainThread(),
+             "Can only convert To WidgetTouchEvent on main thread");
+
+  EventMessage msg = eVoidEvent;
+  uint32_t clickCount = 0;
+  Maybe<WidgetMouseEvent::ExitFrom> exitFrom;
+  switch (mType) {
+    case MOUSE_MOVE:
+      msg = eMouseMove;
+      break;
+    case MOUSE_UP:
+      msg = eMouseUp;
+      clickCount = 1;
+      break;
+    case MOUSE_DOWN:
+      msg = eMouseDown;
+      clickCount = 1;
+      break;
+    case MOUSE_DRAG_START:
+      msg = eDragStart;
+      break;
+    case MOUSE_DRAG_END:
+      msg = eDragEnd;
+      break;
+    case MOUSE_WIDGET_ENTER:
+      msg = eMouseEnterIntoWidget;
+      break;
+    case MOUSE_WIDGET_EXIT:
+      msg = eMouseExitFromWidget;
+      exitFrom = Some(WidgetMouseEvent::ePlatformChild);
+      break;
+    case MOUSE_EXPLORE_BY_TOUCH:
+      msg = eMouseExploreByTouch;
+      break;
+    case MOUSE_HITTEST:
+      msg = eMouseHitTest;
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE(
+          "Did not assign a type to WidgetMouseEvent in MouseInput");
+      break;
+  }
+
+  WidgetMouseEvent event(true, msg, aWidget, WidgetMouseEvent::eReal,
+                         WidgetMouseEvent::eNormal);
+
+  if (msg == eVoidEvent) {
+    return event;
+  }
+
+  switch (mButtonType) {
+    case MouseInput::PRIMARY_BUTTON:
+      event.mButton = MouseButton::ePrimary;
+      break;
+    case MouseInput::MIDDLE_BUTTON:
+      event.mButton = MouseButton::eMiddle;
+      break;
+    case MouseInput::SECONDARY_BUTTON:
+      event.mButton = MouseButton::eSecondary;
+      break;
+    case MouseInput::NONE:
+    default:
+      break;
+  }
+
+  event.mButtons = mButtons;
+  event.mModifiers = modifiers;
+  event.mTimeStamp = mTimeStamp;
+  event.mLayersId = mLayersId;
+  event.mFlags.mHandledByAPZ = mHandledByAPZ;
+  event.mRefPoint = RoundedToInt(ViewAs<LayoutDevicePixel>(
+      mOrigin,
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent));
+  event.mClickCount = clickCount;
+  event.mInputSource = mInputSource;
+  event.mFocusSequenceNumber = mFocusSequenceNumber;
+  event.mExitFrom = exitFrom;
+  event.mClickEventPrevented = mPreventClickEvent;
+
+  return event;
+}
+
+PanGestureInput::PanGestureInput()
+    : InputData(PANGESTURE_INPUT),
+      mType(PANGESTURE_MAYSTART),
+      mLineOrPageDeltaX(0),
+      mLineOrPageDeltaY(0),
+      mUserDeltaMultiplierX(1.0),
+      mUserDeltaMultiplierY(1.0),
+      mHandledByAPZ(false),
+      mOverscrollBehaviorAllowsSwipe(false),
+      mSimulateMomentum(false),
+      mIsNoLineOrPageDelta(true),
+      mMayTriggerSwipe(false) {}
+
+PanGestureInput::PanGestureInput(PanGestureType aType, TimeStamp aTimeStamp,
+                                 const ScreenPoint& aPanStartPoint,
+                                 const ScreenPoint& aPanDisplacement,
+                                 Modifiers aModifiers)
+    : InputData(PANGESTURE_INPUT, aTimeStamp, aModifiers),
+      mType(aType),
+      mPanStartPoint(aPanStartPoint),
+      mPanDisplacement(aPanDisplacement),
+      mLineOrPageDeltaX(0),
+      mLineOrPageDeltaY(0),
+      mUserDeltaMultiplierX(1.0),
+      mUserDeltaMultiplierY(1.0),
+      mHandledByAPZ(false),
+      mOverscrollBehaviorAllowsSwipe(false),
+      mSimulateMomentum(false),
+      mIsNoLineOrPageDelta(true) {
+  mMayTriggerSwipe = SwipeTracker::CanTriggerSwipe(*this);
+}
+
+PanGestureInput::PanGestureInput(PanGestureType aType, TimeStamp aTimeStamp,
+                                 const ScreenPoint& aPanStartPoint,
+                                 const ScreenPoint& aPanDisplacement,
+                                 Modifiers aModifiers,
+                                 IsEligibleForSwipe aIsEligibleForSwipe)
+    : PanGestureInput(aType, aTimeStamp, aPanStartPoint, aPanDisplacement,
+                      aModifiers) {
+  mMayTriggerSwipe &= bool(aIsEligibleForSwipe);
+}
+
+void PanGestureInput::SetLineOrPageDeltas(int32_t aLineOrPageDeltaX,
+                                          int32_t aLineOrPageDeltaY) {
+  mLineOrPageDeltaX = aLineOrPageDeltaX;
+  mLineOrPageDeltaY = aLineOrPageDeltaY;
+  mIsNoLineOrPageDelta = false;
+}
+
+bool PanGestureInput::IsMomentum() const {
+  switch (mType) {
+    case PanGestureInput::PANGESTURE_MOMENTUMSTART:
+    case PanGestureInput::PANGESTURE_MOMENTUMPAN:
+    case PanGestureInput::PANGESTURE_MOMENTUMEND:
+      return true;
+    default:
+      return false;
+  }
+}
+
+WidgetWheelEvent PanGestureInput::ToWidgetEvent(nsIWidget* aWidget) const {
+  WidgetWheelEvent wheelEvent(true, eWheel, aWidget);
+  wheelEvent.mModifiers = this->modifiers;
+  wheelEvent.mTimeStamp = mTimeStamp;
+  wheelEvent.mLayersId = mLayersId;
+  wheelEvent.mRefPoint = RoundedToInt(ViewAs<LayoutDevicePixel>(
+      mPanStartPoint,
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent));
+  wheelEvent.mButtons = 0;
+  wheelEvent.mMayHaveMomentum = true;  // pan inputs may have momentum
+  wheelEvent.mIsMomentum = IsMomentum();
+  wheelEvent.mLineOrPageDeltaX = mLineOrPageDeltaX;
+  wheelEvent.mLineOrPageDeltaY = mLineOrPageDeltaY;
+  wheelEvent.mDeltaX = mPanDisplacement.x;
+  wheelEvent.mDeltaY = mPanDisplacement.y;
+  wheelEvent.mFlags.mHandledByAPZ = mHandledByAPZ;
+  wheelEvent.mFocusSequenceNumber = mFocusSequenceNumber;
+  wheelEvent.mIsNoLineOrPageDelta = mIsNoLineOrPageDelta;
+  if (mDeltaType == PanGestureInput::PANDELTA_PAGE) {
+    // widget/gtk is currently the only consumer that uses delta type
+    // PANDELTA_PAGE
+    // Emulate legacy widget/gtk behavior
+    wheelEvent.mDeltaMode = WheelEvent_Binding::DOM_DELTA_LINE;
+    wheelEvent.mScrollType = WidgetWheelEvent::SCROLL_ASYNCHRONOUSLY;
+    wheelEvent.mDeltaX *= 3;
+    wheelEvent.mDeltaY *= 3;
+  } else {
+    wheelEvent.mDeltaMode = WheelEvent_Binding::DOM_DELTA_PIXEL;
+  }
+  return wheelEvent;
+}
+
+bool PanGestureInput::TransformToLocal(
+    const ScreenToParentLayerMatrix4x4& aTransform) {
+  Maybe<ParentLayerPoint> panStartPoint =
+      UntransformBy(aTransform, mPanStartPoint);
+  if (!panStartPoint) {
+    return false;
+  }
+  mLocalPanStartPoint = *panStartPoint;
+
+  if (mDeltaType == PanGestureInput::PANDELTA_PAGE) {
+    // Skip transforming the pan displacement because we want
+    // raw page proportion counts.
+    mLocalPanDisplacement = ViewAs<ParentLayerPixel>(
+        mPanDisplacement, PixelCastJustification::DeltaIsPageProportion);
+    return true;
+  }
+
+  Maybe<ParentLayerPoint> panDisplacement =
+      UntransformVector(aTransform, mPanDisplacement, mPanStartPoint);
+  if (!panDisplacement) {
+    return false;
+  }
+  mLocalPanDisplacement = *panDisplacement;
+  return true;
+}
+
+ScreenPoint PanGestureInput::UserMultipliedPanDisplacement() const {
+  return ScreenPoint(mPanDisplacement.x * mUserDeltaMultiplierX,
+                     mPanDisplacement.y * mUserDeltaMultiplierY);
+}
+
+ParentLayerPoint PanGestureInput::UserMultipliedLocalPanDisplacement() const {
+  return ParentLayerPoint(mLocalPanDisplacement.x * mUserDeltaMultiplierX,
+                          mLocalPanDisplacement.y * mUserDeltaMultiplierY);
+}
+
+static int32_t TakeLargestInt(gfx::Coord* aCoord) {
+  int32_t result(aCoord->value);  // truncate towards zero
+  aCoord->value -= result;
+  return result;
+}
+
+/* static */ gfx::IntPoint PanGestureInput::GetIntegerDeltaForEvent(
+    bool aIsStart, float x, float y) {
+  static gfx::Point sAccumulator(0.0f, 0.0f);
+  if (aIsStart) {
+    sAccumulator = gfx::Point(0.0f, 0.0f);
+  }
+  sAccumulator.x += x;
+  sAccumulator.y += y;
+  return gfx::IntPoint(TakeLargestInt(&sAccumulator.x),
+                       TakeLargestInt(&sAccumulator.y));
+}
+
+PinchGestureInput::PinchGestureInput()
+    : InputData(PINCHGESTURE_INPUT),
+      mType(PINCHGESTURE_START),
+      mSource(UNKNOWN),
+      mHandledByAPZ(false) {}
+
+PinchGestureInput::PinchGestureInput(
+    PinchGestureType aType, PinchGestureSource aSource, TimeStamp aTimeStamp,
+    const ExternalPoint& aScreenOffset, const ScreenPoint& aFocusPoint,
+    ScreenCoord aCurrentSpan, ScreenCoord aPreviousSpan, Modifiers aModifiers)
+    : InputData(PINCHGESTURE_INPUT, aTimeStamp, aModifiers),
+      mType(aType),
+      mSource(aSource),
+      mFocusPoint(aFocusPoint),
+      mScreenOffset(aScreenOffset),
+      mCurrentSpan(aCurrentSpan),
+      mPreviousSpan(aPreviousSpan),
+      mLineOrPageDeltaY(0),
+      mHandledByAPZ(false) {}
+
+bool PinchGestureInput::TransformToLocal(
+    const ScreenToParentLayerMatrix4x4& aTransform) {
+  Maybe<ParentLayerPoint> point = UntransformBy(aTransform, mFocusPoint);
+  if (!point) {
+    return false;
+  }
+  mLocalFocusPoint = *point;
+  return true;
+}
+
+WidgetWheelEvent PinchGestureInput::ToWidgetEvent(nsIWidget* aWidget) const {
+  WidgetWheelEvent wheelEvent(true, eWheel, aWidget);
+  wheelEvent.mModifiers = this->modifiers | MODIFIER_CONTROL;
+  wheelEvent.mTimeStamp = mTimeStamp;
+  wheelEvent.mLayersId = mLayersId;
+  wheelEvent.mRefPoint = RoundedToInt(ViewAs<LayoutDevicePixel>(
+      mFocusPoint,
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent));
+  wheelEvent.mButtons = 0;
+  wheelEvent.mFlags.mHandledByAPZ = mHandledByAPZ;
+  wheelEvent.mDeltaMode = WheelEvent_Binding::DOM_DELTA_PIXEL;
+
+  wheelEvent.mDeltaY = ComputeDeltaY(aWidget);
+
+  wheelEvent.mLineOrPageDeltaY = mLineOrPageDeltaY;
+
+  MOZ_ASSERT(mType == PINCHGESTURE_END || wheelEvent.mDeltaY != 0.0);
+
+  return wheelEvent;
+}
+
+double PinchGestureInput::ComputeDeltaY(nsIWidget* aWidget) const {
+#if defined(XP_DARWIN)
+  // This converts the pinch gesture value to a fake wheel event that has the
+  // control key pressed so that pages can implement custom pinch gesture
+  // handling. It may seem strange that this doesn't use a wheel event with
+  // the deltaZ property set, but this matches Chrome's behavior as described
+  // at https://code.google.com/p/chromium/issues/detail?id=289887
+  //
+  // The intent of the formula below is to produce numbers similar to Chrome's
+  // implementation of this feature. Chrome implements deltaY using the formula
+  // "-100 * log(1 + [event magnification])" which is unfortunately incorrect.
+  // All deltas for a single pinch gesture should sum to 0 if the start and end
+  // of a pinch gesture end up in the same place. This doesn't happen in Chrome
+  // because they followed Apple's misleading documentation, which implies that
+  // "1 + [event magnification]" is the scale factor. The scale factor is
+  // instead "pow(ratio, [event magnification])" so "[event magnification]" is
+  // already in log space.
+  //
+  // The multiplication by the backing scale factor below counteracts the
+  // division by the backing scale factor in WheelEvent.
+
+  // We want to set deltaY to |-100.0 * M * GetDefaultScaleInternal()| where M
+  // is [event magnification] but [event magnification] is only available in the
+  // macOS widget code so we have to reverse engineer from mCurrentSpan and
+  // mPreviousSpan (which are derived from [event magnification]) to get it.
+  // Specifically, we know |mCurrentSpan == 100.0| and |mPreviousSpan == 100.0 *
+  // (1.0 - M)|. We can calculate deltaY by solving the mPreviousSpan equation
+  // for M in terms of mPreviousSpan and plugging that into to the formula for
+  // deltaY.
+  return (mPreviousSpan - 100.0) *
+         (aWidget ? aWidget->GetDefaultScaleInternal() : 1.f);
+#else
+  // This calculation is based on what the Windows and Linux widget code does.
+  // Specifically, it creates a PinchGestureInput with |mCurrentSpan == 100.0 *
+  // currentScale| and |mPreviousSpan == 100.0 * lastScale| where currentScale
+  // is the scale from the current OS event and lastScale is the scale when the
+  // previous OS event happened. On macOS [event magnification] is a relative
+  // change in scale factor, ie if the scale factor changed from 1 to 1.1 it
+  // will be 0.1, similarly if it changed from 1 to 0.9 it will be -0.1. To
+  // calculate the relative scale change on Windows we would calculate |M =
+  // currentScale - lastScale = (mCurrentSpan-mPreviousSpan)/100| and use the
+  // same formula as the macOS code
+  // (|-100.0 * M * GetDefaultScaleInternal()|).
+
+  return (mPreviousSpan - mCurrentSpan) *
+         (aWidget ? aWidget->GetDefaultScaleInternal() : 1.f);
+#endif
+}
+
+bool PinchGestureInput::SetLineOrPageDeltaY(nsIWidget* aWidget) {
+  double deltaY = ComputeDeltaY(aWidget);
+  if (deltaY == 0 && mType != PINCHGESTURE_END) {
+    return false;
+  }
+  gfx::IntPoint lineOrPageDelta = PinchGestureInput::GetIntegerDeltaForEvent(
+      (mType == PINCHGESTURE_START), 0, deltaY);
+  mLineOrPageDeltaY = lineOrPageDelta.y;
+  if (mLineOrPageDeltaY == 0) {
+    // For PINCHGESTURE_SCALE events, don't dispatch them. Note that the delta
+    // isn't lost; it remains in the accumulator in GetIntegerDeltaForEvent().
+    if (mType == PINCHGESTURE_SCALE) {
+      return false;
+    }
+    // On Windows, drop PINCHGESTURE_START as well (the Windows widget code will
+    // defer the START event until we accumulate enough delta).
+    // The Linux widget code doesn't support this, so instead set the event's
+    // mLineOrPageDeltaY to the smallest nonzero amount in the relevant
+    // direction.
+    if (mType == PINCHGESTURE_START) {
+#ifdef XP_WIN
+      return false;
+#else
+      mLineOrPageDeltaY = (deltaY >= 0) ? 1 : -1;
+#endif
+    }
+    // For PINCHGESTURE_END events, not dispatching a DOMMouseScroll for them is
+    // fine.
+  }
+  return true;
+}
+
+/* static */ gfx::IntPoint PinchGestureInput::GetIntegerDeltaForEvent(
+    bool aIsStart, float x, float y) {
+  static gfx::Point sAccumulator(0.0f, 0.0f);
+  if (aIsStart) {
+    sAccumulator = gfx::Point(0.0f, 0.0f);
+  }
+  sAccumulator.x += x;
+  sAccumulator.y += y;
+  return gfx::IntPoint(TakeLargestInt(&sAccumulator.x),
+                       TakeLargestInt(&sAccumulator.y));
+}
+
+TapGestureInput::TapGestureInput()
+    : InputData(TAPGESTURE_INPUT), mType(TAPGESTURE_LONG) {}
+
+TapGestureInput::TapGestureInput(TapGestureType aType, TimeStamp aTimeStamp,
+                                 const ScreenIntPoint& aPoint,
+                                 Modifiers aModifiers)
+    : InputData(TAPGESTURE_INPUT, aTimeStamp, aModifiers),
+      mType(aType),
+      mPoint(aPoint) {}
+
+TapGestureInput::TapGestureInput(TapGestureType aType, TimeStamp aTimeStamp,
+                                 const ParentLayerPoint& aLocalPoint,
+                                 Modifiers aModifiers)
+    : InputData(TAPGESTURE_INPUT, aTimeStamp, aModifiers),
+      mType(aType),
+      mLocalPoint(aLocalPoint) {}
+
+bool TapGestureInput::TransformToLocal(
+    const ScreenToParentLayerMatrix4x4& aTransform) {
+  Maybe<ParentLayerIntPoint> point = UntransformBy(aTransform, mPoint);
+  if (!point) {
+    return false;
+  }
+  mLocalPoint = *point;
+  return true;
+}
+
+WidgetSimpleGestureEvent TapGestureInput::ToWidgetEvent(
+    nsIWidget* aWidget) const {
+  WidgetSimpleGestureEvent event(true, eTapGesture, aWidget);
+
+  event.mTimeStamp = mTimeStamp;
+  event.mLayersId = mLayersId;
+  event.mRefPoint = ViewAs<LayoutDevicePixel>(
+      mPoint,
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+  event.mButtons = 0;
+  event.mClickCount = 1;
+  event.mModifiers = modifiers;
+
+  return event;
+}
+
+ScrollWheelInput::ScrollWheelInput()
+    : InputData(SCROLLWHEEL_INPUT),
+      mDeltaType(SCROLLDELTA_LINE),
+      mScrollMode(SCROLLMODE_INSTANT),
+      mHandledByAPZ(false),
+      mDeltaX(0.0),
+      mDeltaY(0.0),
+      mLineOrPageDeltaX(0),
+      mLineOrPageDeltaY(0),
+      mScrollSeriesNumber(0),
+      mUserDeltaMultiplierX(1.0),
+      mUserDeltaMultiplierY(1.0),
+      mMayHaveMomentum(false),
+      mIsMomentum(false),
+      mAPZAction(APZWheelAction::Scroll) {}
+
+ScrollWheelInput::ScrollWheelInput(
+    TimeStamp aTimeStamp, Modifiers aModifiers, ScrollMode aScrollMode,
+    ScrollDeltaType aDeltaType, const ScreenPoint& aOrigin, double aDeltaX,
+    double aDeltaY, bool aAllowToOverrideSystemScrollSpeed,
+    WheelDeltaAdjustmentStrategy aWheelDeltaAdjustmentStrategy)
+    : InputData(SCROLLWHEEL_INPUT, aTimeStamp, aModifiers),
+      mDeltaType(aDeltaType),
+      mScrollMode(aScrollMode),
+      mOrigin(aOrigin),
+      mHandledByAPZ(false),
+      mDeltaX(aDeltaX),
+      mDeltaY(aDeltaY),
+      mLineOrPageDeltaX(0),
+      mLineOrPageDeltaY(0),
+      mScrollSeriesNumber(0),
+      mUserDeltaMultiplierX(1.0),
+      mUserDeltaMultiplierY(1.0),
+      mMayHaveMomentum(false),
+      mIsMomentum(false),
+      mAllowToOverrideSystemScrollSpeed(aAllowToOverrideSystemScrollSpeed),
+      mWheelDeltaAdjustmentStrategy(aWheelDeltaAdjustmentStrategy),
+      mAPZAction(APZWheelAction::Scroll) {}
+
+ScrollWheelInput::ScrollWheelInput(const WidgetWheelEvent& aWheelEvent)
+    : InputData(SCROLLWHEEL_INPUT, aWheelEvent.mTimeStamp,
+                aWheelEvent.mModifiers),
+      mDeltaType(DeltaTypeForDeltaMode(aWheelEvent.mDeltaMode)),
+      mScrollMode(SCROLLMODE_INSTANT),
+      mHandledByAPZ(aWheelEvent.mFlags.mHandledByAPZ),
+      mDeltaX(aWheelEvent.mDeltaX),
+      mDeltaY(aWheelEvent.mDeltaY),
+      mWheelTicksX(aWheelEvent.mWheelTicksX),
+      mWheelTicksY(aWheelEvent.mWheelTicksX),
+      mLineOrPageDeltaX(aWheelEvent.mLineOrPageDeltaX),
+      mLineOrPageDeltaY(aWheelEvent.mLineOrPageDeltaY),
+      mScrollSeriesNumber(0),
+      mUserDeltaMultiplierX(1.0),
+      mUserDeltaMultiplierY(1.0),
+      mMayHaveMomentum(aWheelEvent.mMayHaveMomentum),
+      mIsMomentum(aWheelEvent.mIsMomentum),
+      mAllowToOverrideSystemScrollSpeed(
+          aWheelEvent.mAllowToOverrideSystemScrollSpeed),
+      mWheelDeltaAdjustmentStrategy(WheelDeltaAdjustmentStrategy::eNone),
+      mAPZAction(APZWheelAction::Scroll) {
+  mOrigin = ScreenPoint(ViewAs<ScreenPixel>(
+      aWheelEvent.mRefPoint,
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent));
+}
+
+ScrollWheelInput::ScrollDeltaType ScrollWheelInput::DeltaTypeForDeltaMode(
+    uint32_t aDeltaMode) {
+  switch (aDeltaMode) {
+    case WheelEvent_Binding::DOM_DELTA_LINE:
+      return SCROLLDELTA_LINE;
+    case WheelEvent_Binding::DOM_DELTA_PAGE:
+      return SCROLLDELTA_PAGE;
+    case WheelEvent_Binding::DOM_DELTA_PIXEL:
+      return SCROLLDELTA_PIXEL;
+    default:
+      MOZ_CRASH();
+  }
+  return SCROLLDELTA_LINE;
+}
+
+uint32_t ScrollWheelInput::DeltaModeForDeltaType(ScrollDeltaType aDeltaType) {
+  switch (aDeltaType) {
+    case ScrollWheelInput::SCROLLDELTA_LINE:
+      return WheelEvent_Binding::DOM_DELTA_LINE;
+    case ScrollWheelInput::SCROLLDELTA_PAGE:
+      return WheelEvent_Binding::DOM_DELTA_PAGE;
+    case ScrollWheelInput::SCROLLDELTA_PIXEL:
+    default:
+      return WheelEvent_Binding::DOM_DELTA_PIXEL;
+  }
+}
+
+ScrollUnit ScrollWheelInput::ScrollUnitForDeltaType(
+    ScrollDeltaType aDeltaType) {
+  switch (aDeltaType) {
+    case SCROLLDELTA_LINE:
+      return ScrollUnit::LINES;
+    case SCROLLDELTA_PAGE:
+      return ScrollUnit::PAGES;
+    case SCROLLDELTA_PIXEL:
+      return ScrollUnit::DEVICE_PIXELS;
+    default:
+      MOZ_CRASH();
+  }
+  return ScrollUnit::LINES;
+}
+
+WidgetWheelEvent ScrollWheelInput::ToWidgetEvent(nsIWidget* aWidget) const {
+  WidgetWheelEvent wheelEvent(true, eWheel, aWidget);
+  wheelEvent.mModifiers = this->modifiers;
+  wheelEvent.mTimeStamp = mTimeStamp;
+  wheelEvent.mLayersId = mLayersId;
+  wheelEvent.mRefPoint = RoundedToInt(ViewAs<LayoutDevicePixel>(
+      mOrigin,
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent));
+  wheelEvent.mButtons = 0;
+  wheelEvent.mDeltaMode = DeltaModeForDeltaType(mDeltaType);
+  wheelEvent.mMayHaveMomentum = mMayHaveMomentum;
+  wheelEvent.mIsMomentum = mIsMomentum;
+  wheelEvent.mDeltaX = mDeltaX;
+  wheelEvent.mDeltaY = mDeltaY;
+  wheelEvent.mWheelTicksX = mWheelTicksX;
+  wheelEvent.mWheelTicksY = mWheelTicksY;
+  wheelEvent.mLineOrPageDeltaX = mLineOrPageDeltaX;
+  wheelEvent.mLineOrPageDeltaY = mLineOrPageDeltaY;
+  wheelEvent.mAllowToOverrideSystemScrollSpeed =
+      mAllowToOverrideSystemScrollSpeed;
+  wheelEvent.mFlags.mHandledByAPZ = mHandledByAPZ;
+  wheelEvent.mFocusSequenceNumber = mFocusSequenceNumber;
+  return wheelEvent;
+}
+
+bool ScrollWheelInput::TransformToLocal(
+    const ScreenToParentLayerMatrix4x4& aTransform) {
+  Maybe<ParentLayerPoint> point = UntransformBy(aTransform, mOrigin);
+  if (!point) {
+    return false;
+  }
+  mLocalOrigin = *point;
+  return true;
+}
+
+bool ScrollWheelInput::IsCustomizedByUserPrefs() const {
+  return mUserDeltaMultiplierX != 1.0 || mUserDeltaMultiplierY != 1.0;
+}
+
+KeyboardInput::KeyboardInput(const WidgetKeyboardEvent& aEvent)
+    : InputData(KEYBOARD_INPUT, aEvent.mTimeStamp, aEvent.mModifiers),
+      mKeyCode(aEvent.mKeyCode),
+      mCharCode(aEvent.mCharCode),
+      mHandledByAPZ(false) {
+  switch (aEvent.mMessage) {
+    case eKeyPress: {
+      mType = KeyboardInput::KEY_PRESS;
+      break;
+    }
+    case eKeyUp: {
+      mType = KeyboardInput::KEY_UP;
+      break;
+    }
+    case eKeyDown: {
+      mType = KeyboardInput::KEY_DOWN;
+      break;
+    }
+    default:
+      mType = KeyboardInput::KEY_OTHER;
+      break;
+  }
+
+  aEvent.GetShortcutKeyCandidates(mShortcutCandidates);
+}
+
+KeyboardInput::KeyboardInput()
+    : InputData(KEYBOARD_INPUT),
+      mType(KEY_DOWN),
+      mKeyCode(0),
+      mCharCode(0),
+      mHandledByAPZ(false) {}
+
+}  // namespace mozilla
diff --git a/widget/InputData.h b/widget/InputData.h
new file mode 100644
index 0000000000..855cfcd178
--- /dev/null
+++ b/widget/InputData.h
@@ -0,0 +1,835 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef InputData_h__
+#define InputData_h__
+
+#include "nsDebug.h"
+#include "nsPoint.h"
+#include "nsTArray.h"
+#include "Units.h"
+#include "mozilla/ScrollTypes.h"
+#include "mozilla/DefineEnum.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/WheelHandlingHelper.h"  // for WheelDeltaAdjustmentStrategy
+#include "mozilla/gfx/MatrixFwd.h"
+#include "mozilla/layers/APZPublicUtils.h"
+#include "mozilla/layers/KeyboardScrollAction.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/ipc/IPCForwards.h"
+
+template <class E>
+struct already_AddRefed;
+class nsIWidget;
+
+namespace mozilla {
+
+namespace layers {
+class APZInputBridgeChild;
+class PAPZInputBridgeParent;
+}  // namespace layers
+
+namespace dom {
+class Touch;
+}  // namespace dom
+
+// clang-format off
+MOZ_DEFINE_ENUM(
+  InputType, (
+    MULTITOUCH_INPUT,
+    MOUSE_INPUT,
+    PANGESTURE_INPUT,
+    PINCHGESTURE_INPUT,
+    TAPGESTURE_INPUT,
+    SCROLLWHEEL_INPUT,
+    KEYBOARD_INPUT
+));
+// clang-format on
+
+class MultiTouchInput;
+class MouseInput;
+class PanGestureInput;
+class PinchGestureInput;
+class TapGestureInput;
+class ScrollWheelInput;
+class KeyboardInput;
+
+// This looks unnecessary now, but as we add more and more classes that derive
+// from InputType (eventually probably almost as many as *Events.h has), it
+// will be more and more clear what's going on with a macro that shortens the
+// definition of the RTTI functions.
+#define INPUTDATA_AS_CHILD_TYPE(type, enumID)                       \
+  const type& As##type() const {                                    \
+    MOZ_ASSERT(mInputType == enumID, "Invalid cast of InputData."); \
+    return (const type&)*this;                                      \
+  }                                                                 \
+  type& As##type() {                                                \
+    MOZ_ASSERT(mInputType == enumID, "Invalid cast of InputData."); \
+    return (type&)*this;                                            \
+  }
+
+/** Base input data class. Should never be instantiated. */
+class InputData {
+ public:
+  // Warning, this class is serialized and sent over IPC. Any change to its
+  // fields must be reflected in its ParamTraits<>, in nsGUIEventIPC.h
+  InputType mInputType;
+  // Time that this data is relevant to. This only really matters when this data
+  // is used as an event.
+  TimeStamp mTimeStamp;
+  // The sequence number of the last potentially focus changing event handled
+  // by APZ. This is used to track when that event has been processed by
+  // content, and focus can be reconfirmed for async keyboard scrolling.
+  uint64_t mFocusSequenceNumber;
+
+  // The LayersId of the content process that the corresponding WidgetEvent
+  // should be dispatched to.
+  layers::LayersId mLayersId;
+
+  Modifiers modifiers;
+
+  INPUTDATA_AS_CHILD_TYPE(MultiTouchInput, MULTITOUCH_INPUT)
+  INPUTDATA_AS_CHILD_TYPE(MouseInput, MOUSE_INPUT)
+  INPUTDATA_AS_CHILD_TYPE(PanGestureInput, PANGESTURE_INPUT)
+  INPUTDATA_AS_CHILD_TYPE(PinchGestureInput, PINCHGESTURE_INPUT)
+  INPUTDATA_AS_CHILD_TYPE(TapGestureInput, TAPGESTURE_INPUT)
+  INPUTDATA_AS_CHILD_TYPE(ScrollWheelInput, SCROLLWHEEL_INPUT)
+  INPUTDATA_AS_CHILD_TYPE(KeyboardInput, KEYBOARD_INPUT)
+
+  virtual ~InputData();
+  explicit InputData(InputType aInputType);
+
+ protected:
+  InputData(InputType aInputType, TimeStamp aTimeStamp, Modifiers aModifiers);
+};
+
+/**
+ * Data container for a single touch input. Similar to dom::Touch, but used in
+ * off-main-thread situations. This is more for just storing touch data, whereas
+ * dom::Touch is more useful for dispatching through the DOM (which can only
+ * happen on the main thread). dom::Touch also bears the problem of storing
+ * pointers to nsIWidget instances which can only be used on the main thread,
+ * so if instead we used dom::Touch and ever set these pointers
+ * off-main-thread, Bad Things Can Happen(tm).
+ *
+ * Note that this doesn't inherit from InputData because this itself is not an
+ * event. It is only a container/struct that should have any number of instances
+ * within a MultiTouchInput.
+ *
+ * fixme/bug 775746: Make dom::Touch inherit from this class.
+ */
+class SingleTouchData {
+ public:
+  // Construct a SingleTouchData from a Screen point.
+  // mLocalScreenPoint remains (0,0) unless it's set later.
+  SingleTouchData(int32_t aIdentifier, ScreenIntPoint aScreenPoint,
+                  ScreenSize aRadius, float aRotationAngle, float aForce);
+
+  // Construct a SingleTouchData from a ParentLayer point.
+  // mScreenPoint remains (0,0) unless it's set later.
+  // Note: if APZ starts using the radius for anything, we should add a local
+  // version of that too, and have this constructor take it as a
+  // ParentLayerSize.
+  SingleTouchData(int32_t aIdentifier, ParentLayerPoint aLocalScreenPoint,
+                  ScreenSize aRadius, float aRotationAngle, float aForce);
+
+  SingleTouchData();
+
+  already_AddRefed<dom::Touch> ToNewDOMTouch() const;
+
+  // Warning, this class is serialized and sent over IPC. Any change to its
+  // fields must be reflected in its ParamTraits<>, in nsGUIEventIPC.h
+
+  // Historical data of this touch, which  was coalesced into this event.
+  // Touch event coalescing can happen at the system level when the touch
+  // screen's sampling frequency is higher than the vsync rate, or when the
+  // UI thread is busy. When multiple "samples" of touch data are coalesced into
+  // one touch event, the touch event's regular position information is the
+  // information from the last sample. And the previous, "coalesced-away"
+  // samples are stored in mHistoricalData.
+
+  struct HistoricalTouchData {
+    // The timestamp at which the information in this "sample" was originally
+    // sampled.
+    TimeStamp mTimeStamp;
+
+    // The touch data of this historical sample.
+    ScreenIntPoint mScreenPoint;
+    ParentLayerPoint mLocalScreenPoint;
+    ScreenSize mRadius;
+    float mRotationAngle = 0.0f;
+    float mForce = 0.0f;
+  };
+  CopyableTArray<HistoricalTouchData> mHistoricalData;
+
+  // A unique number assigned to each SingleTouchData within a MultiTouchInput
+  // so that they can be easily distinguished when handling a touch
+  // start/move/end.
+  int32_t mIdentifier;
+
+  // Point on the screen that the touch hit, in device pixels. They are
+  // coordinates on the screen.
+  ScreenIntPoint mScreenPoint;
+
+  // |mScreenPoint| transformed to the local coordinates of the APZC targeted
+  // by the hit. This is set and used by APZ.
+  ParentLayerPoint mLocalScreenPoint;
+
+  // Radius that the touch covers, i.e. if you're using your thumb it will
+  // probably be larger than using your pinky, even with the same force.
+  // Radius can be different along x and y. For example, if you press down with
+  // your entire finger vertically, the y radius will be much larger than the x
+  // radius.
+  ScreenSize mRadius;
+
+  float mRotationAngle;
+
+  // How hard the screen is being pressed.
+  float mForce;
+
+  int32_t mTiltX = 0;
+  int32_t mTiltY = 0;
+  int32_t mTwist = 0;
+};
+
+/**
+ * Similar to WidgetTouchEvent, but for use off-main-thread. Also only stores a
+ * screen touch point instead of the many different coordinate spaces
+ * WidgetTouchEvent stores its touch point in. This includes a way to initialize
+ * itself from a WidgetTouchEvent by copying all relevant data over. Note that
+ * this copying from WidgetTouchEvent functionality can only be used on the main
+ * thread.
+ *
+ * Stores an array of SingleTouchData.
+ */
+class MultiTouchInput : public InputData {
+ public:
+  // clang-format off
+  MOZ_DEFINE_ENUM_AT_CLASS_SCOPE(
+    MultiTouchType, (
+      MULTITOUCH_START,
+      MULTITOUCH_MOVE,
+      MULTITOUCH_END,
+      MULTITOUCH_CANCEL
+  ));
+  // clang-format on
+
+  MultiTouchInput(MultiTouchType aType, uint32_t aTime, TimeStamp aTimeStamp,
+                  Modifiers aModifiers);
+  MultiTouchInput();
+  MultiTouchInput(MultiTouchInput&&) = default;
+  MultiTouchInput(const MultiTouchInput&) = default;
+  explicit MultiTouchInput(const WidgetTouchEvent& aTouchEvent);
+
+  MultiTouchInput& operator=(MultiTouchInput&&) = default;
+  MultiTouchInput& operator=(const MultiTouchInput&) = default;
+
+  void Translate(const ScreenPoint& aTranslation);
+
+  WidgetTouchEvent ToWidgetEvent(
+      nsIWidget* aWidget,
+      uint16_t aInputSource =
+          /* MouseEvent_Binding::MOZ_SOURCE_TOUCH = */ 5) const;
+
+  // Return the index into mTouches of the SingleTouchData with the given
+  // identifier, or -1 if there is no such SingleTouchData.
+  int32_t IndexOfTouch(int32_t aTouchIdentifier);
+
+  bool TransformToLocal(const ScreenToParentLayerMatrix4x4& aTransform);
+
+  // Warning, this class is serialized and sent over IPC. Any change to its
+  // fields must be reflected in its ParamTraits<>, in nsGUIEventIPC.h
+  MultiTouchType mType;
+  CopyableTArray<SingleTouchData> mTouches;
+  // The screen offset of the root widget. This can be changing along with
+  // the touch interaction, so we sstore it in the event.
+  ExternalPoint mScreenOffset;
+  bool mHandledByAPZ;
+  // These button fields match to the corresponding fields in
+  // WidgetMouseEventBase, except mButton defaults to -1 to follow PointerEvent.
+  int16_t mButton = eNotPressed;
+  int16_t mButtons = 0;
+};
+
+class MouseInput : public InputData {
+ protected:
+  friend mozilla::layers::APZInputBridgeChild;
+  friend mozilla::layers::PAPZInputBridgeParent;
+  ALLOW_DEPRECATED_READPARAM
+
+  MouseInput();
+
+ public:
+  // clang-format off
+  MOZ_DEFINE_ENUM_AT_CLASS_SCOPE(
+    MouseType, (
+      MOUSE_NONE,
+      MOUSE_MOVE,
+      MOUSE_DOWN,
+      MOUSE_UP,
+      MOUSE_DRAG_START,
+      MOUSE_DRAG_END,
+      MOUSE_WIDGET_ENTER,
+      MOUSE_WIDGET_EXIT,
+      MOUSE_HITTEST,
+      MOUSE_EXPLORE_BY_TOUCH
+  ));
+
+  MOZ_DEFINE_ENUM_AT_CLASS_SCOPE(
+    ButtonType, (
+      PRIMARY_BUTTON,
+      MIDDLE_BUTTON,
+      SECONDARY_BUTTON,
+      NONE
+  ));
+  // clang-format on
+
+  MouseInput(MouseType aType, ButtonType aButtonType, uint16_t aInputSource,
+             int16_t aButtons, const ScreenPoint& aPoint, TimeStamp aTimeStamp,
+             Modifiers aModifiers);
+  explicit MouseInput(const WidgetMouseEventBase& aMouseEvent);
+
+  bool IsLeftButton() const;
+
+  bool TransformToLocal(const ScreenToParentLayerMatrix4x4& aTransform);
+  WidgetMouseEvent ToWidgetEvent(nsIWidget* aWidget) const;
+
+  // Warning, this class is serialized and sent over IPC. Any change to its
+  // fields must be reflected in its ParamTraits<>, in nsGUIEventIPC.h
+  MouseType mType;
+  ButtonType mButtonType;
+  uint16_t mInputSource;
+  int16_t mButtons;
+  ScreenPoint mOrigin;
+  ParentLayerPoint mLocalOrigin;
+  bool mHandledByAPZ;
+  /**
+   * If click event should not be fired in the content after the "mousedown"
+   * event or following "mouseup", set to true.
+   */
+  bool mPreventClickEvent;
+};
+
+/**
+ * Encapsulation class for pan events, can be used off-main-thread.
+ * These events are currently only used for scrolling on desktop.
+ */
+class PanGestureInput : public InputData {
+  friend struct IPC::ParamTraits<PanGestureInput>;
+
+ protected:
+  friend mozilla::layers::APZInputBridgeChild;
+  friend mozilla::layers::PAPZInputBridgeParent;
+  ALLOW_DEPRECATED_READPARAM
+
+  PanGestureInput();
+
+ public:
+  // clang-format off
+  MOZ_DEFINE_ENUM_AT_CLASS_SCOPE(
+    PanGestureType, (
+      // MayStart: Dispatched before any actual panning has occurred but when a
+      // pan gesture is probably about to start, for example when the user
+      // starts touching the touchpad. Should interrupt any ongoing APZ
+      // animation and can be used to trigger scrollability indicators (e.g.
+      // flashing overlay scrollbars).
+      PANGESTURE_MAYSTART,
+
+      // Cancelled: Dispatched after MayStart when no pan gesture is going to
+      // happen after all, for example when the user lifts their fingers from a
+      // touchpad without having done any scrolling.
+      PANGESTURE_CANCELLED,
+
+      // Start: A pan gesture is starting.
+      // For devices that do not support the MayStart event type, this event can
+      // be used to interrupt ongoing APZ animations.
+      PANGESTURE_START,
+
+      // Pan: The actual pan motion by mPanDisplacement.
+      PANGESTURE_PAN,
+
+      // End: The pan gesture has ended, for example because the user has lifted
+      // their fingers from a touchpad after scrolling.
+      // Any potential momentum events fire after this event.
+      PANGESTURE_END,
+
+      // The following momentum event types are used in order to control the pan
+      // momentum animation. Using these instead of our own animation ensures
+      // that the animation curve is OS native and that the animation stops
+      // reliably if it is cancelled by the user.
+
+      // MomentumStart: Dispatched between the End event of the actual
+      // user-controlled pan, and the first MomentumPan event of the momentum
+      // animation.
+      PANGESTURE_MOMENTUMSTART,
+
+      // MomentumPan: The actual momentum motion by mPanDisplacement.
+      PANGESTURE_MOMENTUMPAN,
+
+      // MomentumEnd: The momentum animation has ended, for example because the
+      // momentum velocity has gone below the stopping threshold, or because the
+      // user has stopped the animation by putting their fingers on a touchpad.
+      PANGESTURE_MOMENTUMEND,
+
+      // Interrupted:: A pan gesture started being handled by an APZC but
+      // subsequent pan events might have been consumed by other operations
+      // which haven't been handled by the APZC (e.g. full zoom).
+      PANGESTURE_INTERRUPTED
+  ));
+
+  MOZ_DEFINE_ENUM_AT_CLASS_SCOPE(
+    PanDeltaType, (
+      // There are three kinds of scroll delta modes in Gecko: "page", "line"
+      // and "pixel". Touchpad pan gestures only support "page" and "pixel".
+      //
+      // NOTE: PANDELTA_PAGE currently replicates Gtk behavior
+      // (see AsyncPanZoomController::OnPan).
+      PANDELTA_PAGE,
+      PANDELTA_PIXEL
+  ));
+  // clang-format on
+
+  PanGestureInput(PanGestureType aType, TimeStamp aTimeStamp,
+                  const ScreenPoint& aPanStartPoint,
+                  const ScreenPoint& aPanDisplacement, Modifiers aModifiers);
+
+  enum class IsEligibleForSwipe : bool { No, Yes };
+  PanGestureInput(PanGestureType aType, TimeStamp aTimeStamp,
+                  const ScreenPoint& aPanStartPoint,
+                  const ScreenPoint& aPanDisplacement, Modifiers aModifiers,
+                  IsEligibleForSwipe aIsEligibleForSwipe);
+
+  void SetLineOrPageDeltas(int32_t aLineOrPageDeltaX,
+                           int32_t aLineOrPageDeltaY);
+
+  bool IsMomentum() const;
+
+  WidgetWheelEvent ToWidgetEvent(nsIWidget* aWidget) const;
+
+  bool TransformToLocal(const ScreenToParentLayerMatrix4x4& aTransform);
+
+  ScreenPoint UserMultipliedPanDisplacement() const;
+  ParentLayerPoint UserMultipliedLocalPanDisplacement() const;
+
+  void SetHandledByAPZ(bool aHandled) { mHandledByAPZ = aHandled; }
+  void SetOverscrollBehaviorAllowsSwipe(bool aAllows) {
+    mOverscrollBehaviorAllowsSwipe = aAllows;
+  }
+  void SetSimulateMomentum(bool aSimulate) { mSimulateMomentum = aSimulate; }
+  void SetIsNoLineOrPageDelta(bool aIsNoLineOrPageDelta) {
+    mIsNoLineOrPageDelta = aIsNoLineOrPageDelta;
+  }
+
+  // Returns true if this pan gesture event is elligible for browser swipe
+  // gesture considering the overscroll-behavior property of the target
+  // scroll container.
+  bool AllowsSwipe() const {
+    MOZ_ASSERT(mHandledByAPZ);
+    return mMayTriggerSwipe && mOverscrollBehaviorAllowsSwipe;
+  }
+
+  // Similar to above AllowsSwipe() but this doesn't care the
+  // overscroll-behavior property, this function should be only used for cases
+  // where APZ isn't involved.
+  bool MayTriggerSwipe() const { return mMayTriggerSwipe; }
+  bool RequiresContentResponseIfCannotScrollHorizontallyInStartDirection();
+
+  static gfx::IntPoint GetIntegerDeltaForEvent(bool aIsStart, float x, float y);
+
+  // Warning, this class is serialized and sent over IPC. Any change to its
+  // fields must be reflected in its ParamTraits<>, in nsGUIEventIPC.h
+  PanGestureType mType;
+  ScreenPoint mPanStartPoint;
+
+  // The delta. This can be non-zero on any type of event.
+  ScreenPoint mPanDisplacement;
+
+  // Versions of |mPanStartPoint| and |mPanDisplacement| in the local
+  // coordinates of the APZC receiving the pan. These are set and used by APZ.
+  ParentLayerPoint mLocalPanStartPoint;
+  ParentLayerPoint mLocalPanDisplacement;
+
+  // See lineOrPageDeltaX/Y on WidgetWheelEvent.
+  int32_t mLineOrPageDeltaX;
+  int32_t mLineOrPageDeltaY;
+
+  // User-set delta multipliers.
+  double mUserDeltaMultiplierX;
+  double mUserDeltaMultiplierY;
+
+  PanDeltaType mDeltaType = PANDELTA_PIXEL;
+
+  bool mHandledByAPZ : 1;
+
+  // This is used by APZ to communicate to widget code whether the
+  // overscroll-behavior of the scroll frame handling this swipe allows
+  // non-local overscroll behaviors in the horizontal direction (such as
+  // swipe navigation).
+  bool mOverscrollBehaviorAllowsSwipe : 1;
+
+  // true if APZ should do a fling animation after this pan ends, like
+  // it would with touchscreens. (For platforms that don't emit momentum
+  // events.)
+  bool mSimulateMomentum : 1;
+
+  // true if the creator of this object does not set the mLineOrPageDeltaX/Y
+  // fields and when/if WidgetWheelEvent's are generated from this object wants
+  // the corresponding mLineOrPageDeltaX/Y fields in the WidgetWheelEvent to be
+  // automatically calculated (upon event dispatch by the EventStateManager
+  // code).
+  bool mIsNoLineOrPageDelta : 1;
+
+ private:
+  // If this is true, and this event started a new input block that couldn't
+  // find a scrollable target which is scrollable in the horizontal component
+  // of the scroll start direction, then this input block needs to be put on
+  // hold until a content response has arrived, even if the block has a
+  // confirmed target.
+  // This is used by events that can result in a swipe instead of a scroll.
+  bool mMayTriggerSwipe : 1;
+  void SetMayTriggerSwipe(bool aValue) { mMayTriggerSwipe = aValue; }
+};
+
+/**
+ * Encapsulation class for pinch events. In general, these will be generated by
+ * a gesture listener by looking at SingleTouchData/MultiTouchInput instances
+ * and determining whether or not the user was trying to do a gesture.
+ */
+class PinchGestureInput : public InputData {
+ protected:
+  friend mozilla::layers::APZInputBridgeChild;
+  friend mozilla::layers::PAPZInputBridgeParent;
+  ALLOW_DEPRECATED_READPARAM
+
+  PinchGestureInput();
+
+ public:
+  // clang-format off
+  MOZ_DEFINE_ENUM_AT_CLASS_SCOPE(
+    PinchGestureType, (
+      PINCHGESTURE_START,
+      PINCHGESTURE_SCALE,
+      // The FINGERLIFTED state is used when a touch-based pinch gesture is
+      // terminated by lifting one of the two fingers. The position of the
+      // finger that's still down is populated as the focus point.
+      PINCHGESTURE_FINGERLIFTED,
+      // The END state is used when the pinch gesture is completely terminated.
+      // In this state, the focus point should not be relied upon for having
+      // meaningful data.
+      PINCHGESTURE_END
+  ));
+
+  MOZ_DEFINE_ENUM_AT_CLASS_SCOPE(
+    PinchGestureSource, (
+      UNKNOWN, // Default initialization value. Should never actually be used.
+      TOUCH, // From two-finger pinch gesture
+      ONE_TOUCH, // From one-finger pinch gesture
+      TRACKPAD, // From trackpad pinch gesture
+      MOUSEWHEEL // Synthesized from modifier+mousewheel
+
+      // If adding more items here, increase n_values for the
+      // APZ_ZOOM_PINCHSOURCE Telemetry metric.
+  ));
+  // clang-format on
+
+  // Construct a pinch gesture from a Screen point.
+  PinchGestureInput(PinchGestureType aType, PinchGestureSource aSource,
+                    TimeStamp aTimeStamp, const ExternalPoint& aScreenOffset,
+                    const ScreenPoint& aFocusPoint, ScreenCoord aCurrentSpan,
+                    ScreenCoord aPreviousSpan, Modifiers aModifiers);
+
+  bool TransformToLocal(const ScreenToParentLayerMatrix4x4& aTransform);
+
+  WidgetWheelEvent ToWidgetEvent(nsIWidget* aWidget) const;
+
+  double ComputeDeltaY(nsIWidget* aWidget) const;
+
+  // Set mLineOrPageDeltaY based on ComputeDeltaY().
+  // Return false if the caller should drop this event to ensure
+  // that preventDefault() is respected. (More specifically, this will be
+  // true for event types other than PINCHGESTURE_END if the computed
+  // mLineOrPageDeltaY is zero. In such cases, the resulting DOMMouseScroll
+  // event will not be dispatched, which is a problem if the page is relying
+  // on DOMMouseScroll to prevent browser zooming).
+  // Note that even if the function returns false, the delta from the event
+  // is accumulated and available to be sent in a later event.
+  bool SetLineOrPageDeltaY(nsIWidget* aWidget);
+
+  static gfx::IntPoint GetIntegerDeltaForEvent(bool aIsStart, float x, float y);
+
+  // Warning, this class is serialized and sent over IPC. Any change to its
+  // fields must be reflected in its ParamTraits<>, in nsGUIEventIPC.h
+  PinchGestureType mType;
+
+  // Some indication of the input device that generated this pinch gesture.
+  PinchGestureSource mSource;
+
+  // Center point of the pinch gesture. That is, if there are two fingers on the
+  // screen, it is their midpoint. In the case of more than two fingers, the
+  // point is implementation-specific, but can for example be the midpoint
+  // between the very first and very last touch. This is in device pixels and
+  // are the coordinates on the screen of this midpoint.
+  // For PINCHGESTURE_END events, this may hold the last known focus point or
+  // just be empty; in any case for END events it should not be relied upon.
+  // For PINCHGESTURE_FINGERLIFTED events, this holds the point of the finger
+  // that is still down.
+  ScreenPoint mFocusPoint;
+
+  // The screen offset of the root widget. This can be changing along with
+  // the touch interaction, so we sstore it in the event.
+  ExternalPoint mScreenOffset;
+
+  // |mFocusPoint| transformed to the local coordinates of the APZC targeted
+  // by the hit. This is set and used by APZ.
+  ParentLayerPoint mLocalFocusPoint;
+
+  // The distance between the touches responsible for the pinch gesture.
+  ScreenCoord mCurrentSpan;
+
+  // The previous |mCurrentSpan| in the PinchGestureInput preceding this one.
+  // This is only really relevant during a PINCHGESTURE_SCALE because when it is
+  // of this type then there must have been a history of spans.
+  ScreenCoord mPreviousSpan;
+
+  // We accumulate (via GetIntegerDeltaForEvent) the deltaY that would be
+  // computed by ToWidgetEvent, and then whenever we get a whole integer
+  // value we put it in mLineOrPageDeltaY. Since we only ever use deltaY we
+  // don't need a mLineOrPageDeltaX. This field is used to dispatch legacy mouse
+  // events which are only dispatched when the corresponding field on
+  // WidgetWheelEvent is non-zero.
+  int32_t mLineOrPageDeltaY;
+
+  bool mHandledByAPZ;
+};
+
+/**
+ * Encapsulation class for tap events. In general, these will be generated by
+ * a gesture listener by looking at SingleTouchData/MultiTouchInput instances
+ * and determining whether or not the user was trying to do a gesture.
+ */
+class TapGestureInput : public InputData {
+ protected:
+  friend mozilla::layers::APZInputBridgeChild;
+  friend mozilla::layers::PAPZInputBridgeParent;
+  ALLOW_DEPRECATED_READPARAM
+
+  TapGestureInput();
+
+ public:
+  // clang-format off
+  MOZ_DEFINE_ENUM_AT_CLASS_SCOPE(
+    TapGestureType, (
+      TAPGESTURE_LONG,
+      TAPGESTURE_LONG_UP,
+      TAPGESTURE_UP,
+      TAPGESTURE_CONFIRMED,
+      TAPGESTURE_DOUBLE,
+      TAPGESTURE_SECOND, // See GeckoContentController::TapType::eSecondTap
+      TAPGESTURE_CANCEL
+  ));
+  // clang-format on
+
+  // Construct a tap gesture from a Screen point.
+  // mLocalPoint remains (0,0) unless it's set later.
+  TapGestureInput(TapGestureType aType, TimeStamp aTimeStamp,
+                  const ScreenIntPoint& aPoint, Modifiers aModifiers);
+
+  // Construct a tap gesture from a ParentLayer point.
+  // mPoint remains (0,0) unless it's set later.
+  TapGestureInput(TapGestureType aType, TimeStamp aTimeStamp,
+                  const ParentLayerPoint& aLocalPoint, Modifiers aModifiers);
+
+  bool TransformToLocal(const ScreenToParentLayerMatrix4x4& aTransform);
+
+  WidgetSimpleGestureEvent ToWidgetEvent(nsIWidget* aWidget) const;
+
+  // Warning, this class is serialized and sent over IPC. Any change to its
+  // fields must be reflected in its ParamTraits<>, in nsGUIEventIPC.h
+  TapGestureType mType;
+
+  // The location of the tap in screen pixels.
+  ScreenIntPoint mPoint;
+
+  // The location of the tap in the local coordinates of the APZC receiving it.
+  // This is set and used by APZ.
+  ParentLayerPoint mLocalPoint;
+};
+
+// Encapsulation class for scroll-wheel events. These are generated by mice
+// with physical scroll wheels, and on Windows by most touchpads when using
+// scroll gestures.
+class ScrollWheelInput : public InputData {
+ protected:
+  friend mozilla::layers::APZInputBridgeChild;
+  friend mozilla::layers::PAPZInputBridgeParent;
+  ALLOW_DEPRECATED_READPARAM
+
+  typedef mozilla::layers::APZWheelAction APZWheelAction;
+
+  ScrollWheelInput();
+
+ public:
+  // clang-format off
+  MOZ_DEFINE_ENUM_AT_CLASS_SCOPE(
+    ScrollDeltaType, (
+      // There are three kinds of scroll delta modes in Gecko: "page", "line"
+      // and "pixel".
+      SCROLLDELTA_LINE,
+      SCROLLDELTA_PAGE,
+      SCROLLDELTA_PIXEL
+  ));
+
+  MOZ_DEFINE_ENUM_AT_CLASS_SCOPE(
+    ScrollMode, (
+      SCROLLMODE_INSTANT,
+      SCROLLMODE_SMOOTH
+    )
+  );
+  // clang-format on
+
+  ScrollWheelInput(TimeStamp aTimeStamp, Modifiers aModifiers,
+                   ScrollMode aScrollMode, ScrollDeltaType aDeltaType,
+                   const ScreenPoint& aOrigin, double aDeltaX, double aDeltaY,
+                   bool aAllowToOverrideSystemScrollSpeed,
+                   WheelDeltaAdjustmentStrategy aWheelDeltaAdjustmentStrategy);
+  explicit ScrollWheelInput(const WidgetWheelEvent& aEvent);
+
+  static ScrollDeltaType DeltaTypeForDeltaMode(uint32_t aDeltaMode);
+  static uint32_t DeltaModeForDeltaType(ScrollDeltaType aDeltaType);
+  static mozilla::ScrollUnit ScrollUnitForDeltaType(ScrollDeltaType aDeltaType);
+
+  WidgetWheelEvent ToWidgetEvent(nsIWidget* aWidget) const;
+  bool TransformToLocal(const ScreenToParentLayerMatrix4x4& aTransform);
+
+  bool IsCustomizedByUserPrefs() const;
+
+  // The following two functions are for auto-dir scrolling. For detailed
+  // information on auto-dir, @see mozilla::WheelDeltaAdjustmentStrategy
+  bool IsAutoDir(bool aForce = false) const {
+    if (aForce) {
+      return true;
+    }
+
+    switch (mWheelDeltaAdjustmentStrategy) {
+      case WheelDeltaAdjustmentStrategy::eAutoDir:
+      case WheelDeltaAdjustmentStrategy::eAutoDirWithRootHonour:
+        return true;
+      default:
+        // Prevent compilation errors generated by -Werror=switch
+        break;
+    }
+    return false;
+  }
+  // Indicates which element this scroll honours if it's an auto-dir scroll.
+  // If true, honour the root element; otherwise, honour the currently scrolling
+  // target.
+  // Note that if IsAutoDir() returns false, then this function also returns
+  // false, but false in this case is meaningless as IsAutoDir() indicates it's
+  // not an auto-dir scroll.
+  // For detailed information on auto-dir,
+  // @see mozilla::WheelDeltaAdjustmentStrategy
+  bool HonoursRoot(bool aForce = false) const {
+    return WheelDeltaAdjustmentStrategy::eAutoDirWithRootHonour ==
+               mWheelDeltaAdjustmentStrategy ||
+           aForce;
+  }
+
+  // Warning, this class is serialized and sent over IPC. Any change to its
+  // fields must be reflected in its ParamTraits<>, in nsGUIEventIPC.h
+  ScrollDeltaType mDeltaType;
+  ScrollMode mScrollMode;
+  ScreenPoint mOrigin;
+
+  bool mHandledByAPZ;
+
+  // Deltas are in units corresponding to the delta type. For line deltas, they
+  // are the number of line units to scroll. The number of device pixels for a
+  // horizontal and vertical line unit are in FrameMetrics::mLineScrollAmount.
+  // For pixel deltas, these values are in ScreenCoords.
+  //
+  // The horizontal (X) delta is > 0 for scrolling right and < 0 for scrolling
+  // left. The vertical (Y) delta is < 0 for scrolling up and > 0 for
+  // scrolling down.
+  double mDeltaX;
+  double mDeltaY;
+
+  // The number of scroll wheel ticks.
+  double mWheelTicksX = 0.0;
+  double mWheelTicksY = 0.0;
+
+  // The location of the scroll in local coordinates. This is set and used by
+  // APZ.
+  ParentLayerPoint mLocalOrigin;
+
+  // See lineOrPageDeltaX/Y on WidgetWheelEvent.
+  int32_t mLineOrPageDeltaX;
+  int32_t mLineOrPageDeltaY;
+
+  // Indicates the order in which this event was added to a transaction. The
+  // first event is 1; if not a member of a transaction, this is 0.
+  uint32_t mScrollSeriesNumber;
+
+  // User-set delta multipliers.
+  double mUserDeltaMultiplierX;
+  double mUserDeltaMultiplierY;
+
+  bool mMayHaveMomentum;
+  bool mIsMomentum;
+  bool mAllowToOverrideSystemScrollSpeed;
+
+  // Sometimes a wheel event input's wheel delta should be adjusted. This member
+  // specifies how to adjust the wheel delta.
+  WheelDeltaAdjustmentStrategy mWheelDeltaAdjustmentStrategy;
+
+  APZWheelAction mAPZAction;
+};
+
+class KeyboardInput : public InputData {
+ public:
+  typedef mozilla::layers::KeyboardScrollAction KeyboardScrollAction;
+
+  // Note that if you change the first member in this enum(I.e. KEY_DOWN) to one
+  // other member, don't forget to update the minimum value in
+  // ContiguousEnumSerializer for KeyboardEventType in widget/nsGUIEventIPC
+  // accordingly.
+  enum KeyboardEventType {
+    KEY_DOWN,
+    KEY_PRESS,
+    KEY_UP,
+    // Any other key event such as eAccessKeyNotFound
+    KEY_OTHER,
+
+    // Used as an upper bound for ContiguousEnumSerializer
+    KEY_SENTINEL,
+  };
+
+  explicit KeyboardInput(const WidgetKeyboardEvent& aEvent);
+
+  // Warning, this class is serialized and sent over IPC. Any change to its
+  // fields must be reflected in its ParamTraits<>, in nsGUIEventIPC.h
+
+  KeyboardEventType mType;
+  uint32_t mKeyCode;
+  uint32_t mCharCode;
+  CopyableTArray<ShortcutKeyCandidate> mShortcutCandidates;
+
+  bool mHandledByAPZ;
+
+  // The scroll action to perform on a layer for this keyboard input. This is
+  // only used in APZ and is NOT serialized over IPC.
+  KeyboardScrollAction mAction;
+
+ protected:
+  friend mozilla::layers::APZInputBridgeChild;
+  friend mozilla::layers::PAPZInputBridgeParent;
+  ALLOW_DEPRECATED_READPARAM
+
+  KeyboardInput();
+};
+
+}  // namespace mozilla
+
+#endif  // InputData_h__
diff --git a/widget/LSBUtils.cpp b/widget/LSBUtils.cpp
new file mode 100644
index 0000000000..9ebffacd7e
--- /dev/null
+++ b/widget/LSBUtils.cpp
@@ -0,0 +1,142 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LSBUtils.h"
+
+#include <fstream>
+#include <string>
+#include <string_view>
+#include <unistd.h>
+#include "base/process_util.h"
+#include "mozilla/FileUtils.h"
+#include "mozilla/Result.h"
+#include "mozilla/ResultVariant.h"
+#include "mozilla/ipc/LaunchError.h"
+
+namespace mozilla::widget::lsb {
+
+static const char gLsbReleasePath[] = "/usr/bin/lsb_release";
+static const char gEtcOsReleasePath[] = "/etc/os-release";
+static const char gUsrOsReleasePath[] = "/usr/lib/os-release";
+
+// See https://www.freedesktop.org/software/systemd/man/latest/os-release.html
+bool ExtractAndSetValue(nsACString& aContainer, std::string_view& aValue) {
+  // We assume the value is well formed and doesn't contain escape characters.
+  if (aValue.size() > 1 && (aValue.front() == '"' || aValue.front() == '\'')) {
+    // We assume the quote is properly balanced.
+    aValue = aValue.substr(1, aValue.size() - 2);
+  }
+  aContainer.Assign(aValue.data(), aValue.size());
+  return !aValue.empty();
+}
+
+bool GetOSRelease(nsACString& aDistributor, nsACString& aDescription,
+                  nsACString& aRelease, nsACString& aCodename) {
+  std::ifstream stream(gEtcOsReleasePath);
+  if (stream.fail()) {
+    stream.open(gUsrOsReleasePath);
+    if (stream.fail()) {
+      return false;
+    }
+  }
+  bool seen_id = false, seen_pretty_name = false, seen_version_id = false;
+  std::string rawline;
+  nsAutoCString name;
+  while (std::getline(stream, rawline)) {
+    std::string_view line(rawline);
+    size_t pos = line.find('=');
+    if (pos != std::string_view::npos) {
+      auto key = line.substr(0, pos);
+      auto value = line.substr(pos + 1);
+      if (key == "ID") {
+        if (ExtractAndSetValue(aDistributor, value)) {
+          // Capitalize the first letter of the id. This mimics what
+          // lsb_release does on Debian and derivatives. On RH derivatives,
+          // ID tends to be capitalized already.
+          char* c = aDistributor.BeginWriting();
+          if (*c >= 'a' && *c <= 'z') {
+            *c -= ('a' - 'A');
+          }
+          seen_id = true;
+        }
+      } else if (key == "NAME") {
+        ExtractAndSetValue(name, value);
+      } else if (key == "PRETTY_NAME") {
+        if (ExtractAndSetValue(aDescription, value)) seen_pretty_name = true;
+      } else if (key == "VERSION_ID") {
+        if (ExtractAndSetValue(aRelease, value)) seen_version_id = true;
+      } else if (key == "VERSION_CODENAME") {
+        ExtractAndSetValue(aCodename, value);
+      }
+    }
+  }
+  // If NAME is set and only differs from ID in case, use NAME.
+  if (seen_id && !name.IsEmpty() && name.EqualsIgnoreCase(aDistributor)) {
+    aDistributor = name;
+  }
+  // Only consider our work done if we've seen at least ID, PRETTY_NAME and
+  // VERSION_ID.
+  return seen_id && seen_pretty_name && seen_version_id;
+}
+
+bool GetLSBRelease(nsACString& aDistributor, nsACString& aDescription,
+                   nsACString& aRelease, nsACString& aCodename) {
+  // Nowadays, /etc/os-release is more likely to be available than
+  // /usr/bin/lsb_release. Relying on the former also avoids forking.
+  if (GetOSRelease(aDistributor, aDescription, aRelease, aCodename)) {
+    return true;
+  }
+
+  if (access(gLsbReleasePath, R_OK) != 0) return false;
+
+  int pipefd[2];
+  if (pipe(pipefd) == -1) {
+    NS_WARNING("pipe() failed!");
+    return false;
+  }
+
+  std::vector<std::string> argv = {gLsbReleasePath, "-idrc"};
+
+  base::LaunchOptions options;
+  options.fds_to_remap.push_back({pipefd[1], STDOUT_FILENO});
+  options.wait = true;
+
+  base::ProcessHandle process;
+  Result<Ok, ipc::LaunchError> err =
+      base::LaunchApp(argv, std::move(options), &process);
+  close(pipefd[1]);
+  if (err.isErr()) {
+    NS_WARNING("Failed to spawn lsb_release!");
+    close(pipefd[0]);
+    return false;
+  }
+
+  ScopedCloseFile stream(fdopen(pipefd[0], "r"));
+  if (!stream) {
+    NS_WARNING("Could not wrap fd!");
+    close(pipefd[0]);
+    return false;
+  }
+
+  char dist[256], desc[256], release[256], codename[256];
+  if (fscanf(stream.get(),
+             "Distributor ID:\t%255[^\n]\n"
+             "Description:\t%255[^\n]\n"
+             "Release:\t%255[^\n]\n"
+             "Codename:\t%255[^\n]\n",
+             dist, desc, release, codename) != 4) {
+    NS_WARNING("Failed to parse lsb_release!");
+    return false;
+  }
+
+  aDistributor.Assign(dist);
+  aDescription.Assign(desc);
+  aRelease.Assign(release);
+  aCodename.Assign(codename);
+  return true;
+}
+
+}  // namespace mozilla::widget::lsb
diff --git a/widget/LSBUtils.h b/widget/LSBUtils.h
new file mode 100644
index 0000000000..37d4c400ad
--- /dev/null
+++ b/widget/LSBUtils.h
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _MOZILLA_WIDGET_LSB_UTILS_H
+#define _MOZILLA_WIDGET_LSB_UTILS_H
+
+#include "nsString.h"
+
+namespace mozilla {
+namespace widget {
+namespace lsb {
+
+// Fetches the LSB release data by parsing the lsb_release command.
+// Returns false if the lsb_release command was not found, or parsing failed.
+bool GetLSBRelease(nsACString& aDistributor, nsACString& aDescription,
+                   nsACString& aRelease, nsACString& aCodename);
+
+}  // namespace lsb
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // _MOZILLA_WIDGET_LSB_UTILS_H
diff --git a/widget/LookAndFeel.h b/widget/LookAndFeel.h
new file mode 100644
index 0000000000..2ab61df304
--- /dev/null
+++ b/widget/LookAndFeel.h
@@ -0,0 +1,585 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __LookAndFeel
+#define __LookAndFeel
+
+#ifndef MOZILLA_INTERNAL_API
+#  error "This header is only usable from within libxul (MOZILLA_INTERNAL_API)."
+#endif
+
+#include "nsDebug.h"
+#include "nsColor.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/widget/ThemeChangeKind.h"
+#include "mozilla/ColorScheme.h"
+
+struct gfxFontStyle;
+
+class nsIFrame;
+
+namespace mozilla {
+
+using Modifiers = uint16_t;
+struct StyleColorSchemeFlags;
+
+namespace dom {
+class Document;
+}
+
+namespace widget {
+class FullLookAndFeel;
+}  // namespace widget
+
+enum class StyleSystemColor : uint8_t;
+enum class StyleSystemColorScheme : uint8_t;
+enum class StyleSystemFont : uint8_t;
+
+class LookAndFeel {
+ public:
+  using ColorID = StyleSystemColor;
+  using ColorScheme = mozilla::ColorScheme;
+
+  // When modifying this list, also modify nsXPLookAndFeel::sIntPrefs
+  // in widget/xpwidgts/nsXPLookAndFeel.cpp.
+  enum class IntID {
+    // default, may be overriden by OS
+    CaretBlinkTime,
+    // Amount of blinks that happen before the caret stops blinking.
+    CaretBlinkCount,
+    // pixel width of caret
+    CaretWidth,
+    // show the caret when text is selected?
+    ShowCaretDuringSelection,
+    // select textfields when focused via tab/accesskey?
+    SelectTextfieldsOnKeyFocus,
+    // delay before submenus open
+    SubmenuDelay,
+    // can popups overlap menu/task bar?
+    MenusCanOverlapOSBar,
+    // should overlay scrollbars be used?
+    UseOverlayScrollbars,
+    // allow H and V overlay scrollbars to overlap?
+    AllowOverlayScrollbarsOverlap,
+    // skip navigating to disabled menu item?
+    SkipNavigatingDisabledMenuItem,
+    // begin a drag if the mouse is moved further than the threshold while the
+    // button is down
+    DragThresholdX,
+    DragThresholdY,
+    // Accessibility theme being used?
+    UseAccessibilityTheme,
+
+    // position of scroll arrows in a scrollbar
+    ScrollArrowStyle,
+
+    // each button can take one of four values:
+    ScrollButtonLeftMouseButtonAction,
+    // 0 - scrolls one  line, 1 - scrolls one page
+    ScrollButtonMiddleMouseButtonAction,
+    // 2 - scrolls to end, 3 - button ignored
+    ScrollButtonRightMouseButtonAction,
+
+    // delay for opening spring loaded folders
+    TreeOpenDelay,
+    // delay for closing spring loaded folders
+    TreeCloseDelay,
+    // delay for triggering the tree scrolling
+    TreeLazyScrollDelay,
+    // delay for scrolling the tree
+    TreeScrollDelay,
+    // the maximum number of lines to be scrolled at ones
+    TreeScrollLinesMax,
+    // What type of tab-order to use
+    TabFocusModel,
+    // Should menu items blink when they're chosen?
+    ChosenMenuItemsShouldBlink,
+
+    /*
+     * A Boolean value to determine whether the Windows accent color
+     * should be applied to the title bar.
+     *
+     * The value of this metric is not used on other platforms. These platforms
+     * should return NS_ERROR_NOT_IMPLEMENTED when queried for this metric.
+     */
+    WindowsAccentColorInTitlebar,
+
+    /*
+     * A Boolean value to determine whether the macOS Big Sur-specific
+     * theming should be used.
+     */
+    MacBigSurTheme,
+
+    /*
+     * A Boolean value to determine whether macOS is in RTL mode or not.
+     */
+    MacRTL,
+
+    /*
+     * AlertNotificationOrigin indicates from which corner of the
+     * screen alerts slide in, and from which direction (horizontal/vertical).
+     * 0, the default, represents bottom right, sliding vertically.
+     * Use any bitwise combination of the following constants:
+     * NS_ALERT_HORIZONTAL (1), NS_ALERT_LEFT (2), NS_ALERT_TOP (4).
+     *
+     *       6       4
+     *     +-----------+
+     *    7|           |5
+     *     |           |
+     *    3|           |1
+     *     +-----------+
+     *       2       0
+     */
+    AlertNotificationOrigin,
+
+    /**
+     * If true, clicking on a scrollbar (not as in dragging the thumb) defaults
+     * to scrolling the view corresponding to the clicked point. Otherwise, we
+     * only do so if the scrollbar is clicked using the middle mouse button or
+     * if shift is pressed when the scrollbar is clicked.
+     */
+    ScrollToClick,
+
+    /**
+     * IME and spell checker underline styles, the values should be
+     * NS_DECORATION_LINE_STYLE_*.  They are defined below.
+     */
+    IMERawInputUnderlineStyle,
+    IMESelectedRawTextUnderlineStyle,
+    IMEConvertedTextUnderlineStyle,
+    IMESelectedConvertedTextUnderline,
+    SpellCheckerUnderlineStyle,
+
+    /**
+     * If this metric != 0, support window dragging on the menubar.
+     */
+    MenuBarDrag,
+    /**
+     * 0: scrollbar button repeats to scroll only when cursor is on the button.
+     * 1: scrollbar button repeats to scroll even if cursor is outside of it.
+     */
+    ScrollbarButtonAutoRepeatBehavior,
+    /**
+     * Delay before showing a tooltip.
+     */
+    TooltipDelay,
+    /*
+     * A Boolean value to determine whether swipe animations should be used.
+     */
+    SwipeAnimationEnabled,
+
+    /*
+     * Controls whether overlay scrollbars display when the user moves
+     * the mouse in a scrollable frame.
+     */
+    ScrollbarDisplayOnMouseMove,
+
+    /*
+     * Overlay scrollbar animation constants.
+     */
+    ScrollbarFadeBeginDelay,
+    ScrollbarFadeDuration,
+
+    /**
+     * Distance in pixels to offset the context menu from the cursor
+     * on open.
+     */
+    ContextMenuOffsetVertical,
+    ContextMenuOffsetHorizontal,
+
+    /*
+     * A boolean value indicating whether client-side decorations are
+     * supported by the user's GTK version.
+     */
+    GTKCSDAvailable,
+
+    /*
+     * A boolean value indicating whether client-side decorations should
+     * contain a minimize button.
+     */
+    GTKCSDMinimizeButton,
+
+    /*
+     * A boolean value indicating whether client-side decorations should
+     * contain a maximize button.
+     */
+    GTKCSDMaximizeButton,
+
+    /*
+     * A boolean value indicating whether client-side decorations should
+     * contain a close button.
+     */
+    GTKCSDCloseButton,
+
+    /**
+     * An Integer value that will represent the position of the Minimize button
+     * in GTK Client side decoration header.
+     */
+    GTKCSDMinimizeButtonPosition,
+
+    /**
+     * An Integer value that will represent the position of the Maximize button
+     * in GTK Client side decoration header.
+     */
+    GTKCSDMaximizeButtonPosition,
+
+    /**
+     * An Integer value that will represent the position of the Close button
+     * in GTK Client side decoration header.
+     */
+    GTKCSDCloseButtonPosition,
+
+    /*
+     * A boolean value indicating whether titlebar buttons are located
+     * in left titlebar corner.
+     */
+    GTKCSDReversedPlacement,
+
+    /*
+     * A boolean value indicating whether or not the OS is using a dark theme,
+     * which we may want to switch to as well if not overridden by the user.
+     */
+    SystemUsesDarkTheme,
+
+    /**
+     * Corresponding to prefers-reduced-motion.
+     * https://drafts.csswg.org/mediaqueries-5/#prefers-reduced-motion
+     * 0: no-preference
+     * 1: reduce
+     */
+    PrefersReducedMotion,
+
+    /**
+     * Corresponding to prefers-reduced-transparency.
+     * https://drafts.csswg.org/mediaqueries-5/#prefers-reduced-transparency
+     * 0: no-preference
+     * 1: reduce
+     */
+    PrefersReducedTransparency,
+
+    /**
+     * Corresponding to inverted-colors.
+     * https://drafts.csswg.org/mediaqueries-5/#inverted
+     * 0: none
+     * 1: inverted
+     */
+    InvertedColors,
+
+    /**
+     * Corresponding to PointerCapabilities in ServoTypes.h
+     * 0: None
+     * 1: Coarse
+     * 2: Fine
+     * 4: Hover
+     */
+    PrimaryPointerCapabilities,
+    /**
+     * Corresponding to union of PointerCapabilities values in ServoTypes.h
+     * E.g. if there is a mouse and a digitizer, the value will be
+     * 'Coarse | Fine | Hover'.
+     */
+    AllPointerCapabilities,
+
+    /** The scrollbar size, in CSS pixels. */
+    SystemScrollbarSize,
+
+    /** A boolean value to determine whether a touch device is present */
+    TouchDeviceSupportPresent,
+
+    /** GTK titlebar radius */
+    TitlebarRadius,
+
+    /**
+     * Corresponding to dynamic-range.
+     * https://drafts.csswg.org/mediaqueries-5/#dynamic-range
+     * 0: Standard
+     * 1: High
+     */
+    DynamicRange,
+    VideoDynamicRange,
+
+    /** Whether XUL panel animations are enabled. */
+    PanelAnimations,
+
+    /* Whether we should hide the cursor while typing */
+    HideCursorWhileTyping,
+
+    /* The StyleGtkThemeFamily of the current GTK theme. */
+    GTKThemeFamily,
+
+    /*
+     * Not an ID; used to define the range of valid IDs.  Must be last.
+     */
+    End,
+  };
+
+  // This is a common enough integer that seems worth the shortcut.
+  static bool UseOverlayScrollbars() {
+    return GetInt(IntID::UseOverlayScrollbars);
+  }
+
+  // Returns keyCode value of a modifier key which is used for accesskey.
+  // Returns 0 if the platform doesn't support access key.
+  static uint32_t GetMenuAccessKey();
+  // Modifier mask for the menu accesskey.
+  static Modifiers GetMenuAccessKeyModifiers();
+
+  enum {
+    eScrollArrow_None = 0,
+    eScrollArrow_StartBackward = 0x1000,
+    eScrollArrow_StartForward = 0x0100,
+    eScrollArrow_EndBackward = 0x0010,
+    eScrollArrow_EndForward = 0x0001
+  };
+
+  enum {
+    // single arrow at each end
+    eScrollArrowStyle_Single =
+        eScrollArrow_StartBackward | eScrollArrow_EndForward,
+    // both arrows at bottom/right, none at top/left
+    eScrollArrowStyle_BothAtBottom =
+        eScrollArrow_EndBackward | eScrollArrow_EndForward,
+    // both arrows at both ends
+    eScrollArrowStyle_BothAtEachEnd =
+        eScrollArrow_EndBackward | eScrollArrow_EndForward |
+        eScrollArrow_StartBackward | eScrollArrow_StartForward,
+    // both arrows at top/left, none at bottom/right
+    eScrollArrowStyle_BothAtTop =
+        eScrollArrow_StartBackward | eScrollArrow_StartForward
+  };
+
+  // When modifying this list, also modify nsXPLookAndFeel::sFloatPrefs
+  // in widget/nsXPLookAndFeel.cpp.
+  enum class FloatID {
+    IMEUnderlineRelativeSize,
+    SpellCheckerUnderlineRelativeSize,
+
+    // The width/height ratio of the cursor. If used, the CaretWidth int metric
+    // should be added to the calculated caret width.
+    CaretAspectRatio,
+
+    // GTK text scale factor.
+    TextScaleFactor,
+
+    // Mouse pointer scaling factor.
+    CursorScale,
+
+    // Not an ID; used to define the range of valid IDs.  Must be last.
+    End,
+  };
+
+  using FontID = mozilla::StyleSystemFont;
+
+  static ColorScheme SystemColorScheme() {
+    return GetInt(IntID::SystemUsesDarkTheme) ? ColorScheme::Dark
+                                              : ColorScheme::Light;
+  }
+
+  static bool IsDarkColor(nscolor);
+
+  static ColorScheme ColorSchemeForStyle(
+      const dom::Document&, const StyleColorSchemeFlags&,
+      ColorSchemeMode = ColorSchemeMode::Used);
+  static ColorScheme ColorSchemeForFrame(
+      const nsIFrame*, ColorSchemeMode = ColorSchemeMode::Used);
+
+  // Whether standins for native colors should be used (that is, colors faked,
+  // taken from win7, mostly). This forces light appearance, effectively.
+  enum class UseStandins : bool { No, Yes };
+  static UseStandins ShouldUseStandins(const dom::Document&, ColorID);
+
+  // Returns a native color value (might be overwritten by prefs) for a given
+  // color id.
+  //
+  // NOTE:
+  //   ColorID::TextSelectForeground might return NS_SAME_AS_FOREGROUND_COLOR.
+  //   ColorID::IME* might return NS_TRANSPARENT, NS_SAME_AS_FOREGROUND_COLOR or
+  //   NS_40PERCENT_FOREGROUND_COLOR.
+  //   These values have particular meaning.  Then, they are not an actual
+  //   color value.
+  static Maybe<nscolor> GetColor(ColorID, ColorScheme, UseStandins);
+
+  // Gets the color with appropriate defaults for UseStandins, ColorScheme etc
+  // for a given frame.
+  static Maybe<nscolor> GetColor(ColorID, const nsIFrame*);
+
+  // Versions of the above which returns the color if found, or a default (which
+  // defaults to opaque black) otherwise.
+  static nscolor Color(ColorID aId, ColorScheme aScheme,
+                       UseStandins aUseStandins,
+                       nscolor aDefault = NS_RGB(0, 0, 0)) {
+    return GetColor(aId, aScheme, aUseStandins).valueOr(aDefault);
+  }
+
+  static nscolor Color(ColorID aId, nsIFrame* aFrame,
+                       nscolor aDefault = NS_RGB(0, 0, 0)) {
+    return GetColor(aId, aFrame).valueOr(aDefault);
+  }
+
+  static float GetTextScaleFactor() {
+    float f = GetFloat(FloatID::TextScaleFactor, 1.0f);
+    if (MOZ_UNLIKELY(f <= 0.0f)) {
+      return 1.0f;
+    }
+    return f;
+  }
+
+  struct ZoomSettings {
+    float mFullZoom = 1.0f;
+    float mTextZoom = 1.0f;
+  };
+
+  static ZoomSettings SystemZoomSettings();
+
+  /**
+   * GetInt() and GetFloat() return a int or float value for aID.  The result
+   * might be distance, time, some flags or a int value which has particular
+   * meaning.  See each document at definition of each ID for the detail.
+   * The result is always 0 when they return error.  Therefore, if you want to
+   * use a value for the default value, you should use the other method which
+   * returns int or float directly.
+   */
+  static nsresult GetInt(IntID, int32_t* aResult);
+  static nsresult GetFloat(FloatID aID, float* aResult);
+
+  static int32_t GetInt(IntID aID, int32_t aDefault = 0) {
+    int32_t result;
+    if (NS_FAILED(GetInt(aID, &result))) {
+      return aDefault;
+    }
+    return result;
+  }
+
+  static float GetFloat(FloatID aID, float aDefault = 0.0f) {
+    float result;
+    if (NS_FAILED(GetFloat(aID, &result))) {
+      return aDefault;
+    }
+    return result;
+  }
+
+  /**
+   * Retrieve the name and style of a system-theme font.  Returns true
+   * if the system theme specifies this font, false if a default should
+   * be used.  In the latter case neither aName nor aStyle is modified.
+   *
+   * Size of the font should be in CSS pixels, not device pixels.
+   *
+   * @param aID    Which system-theme font is wanted.
+   * @param aName  The name of the font to use.
+   * @param aStyle Styling to apply to the font.
+   */
+  static bool GetFont(FontID aID, nsString& aName, gfxFontStyle& aStyle);
+
+  /**
+   * GetPasswordCharacter() returns a unicode character which should be used
+   * for a masked character in password editor.  E.g., '*'.
+   */
+  static char16_t GetPasswordCharacter();
+
+  /**
+   * If the latest character in password field shouldn't be hidden by the
+   * result of GetPasswordCharacter(), GetEchoPassword() returns TRUE.
+   * Otherwise, FALSE.
+   */
+  static bool GetEchoPassword();
+
+  /**
+   * Whether we should be drawing in the titlebar by default.
+   */
+  static bool DrawInTitlebar();
+
+  enum class TitlebarAction {
+    None,
+    WindowLower,
+    WindowMenu,
+    WindowMinimize,
+    WindowMaximize,
+    WindowMaximizeToggle,
+    // We don't support more actions (maximize-horizontal, maximize-vertical,..)
+    // as they're implemented as part of Wayland gtk_surface1 protocol
+    // which is not accessible to us.
+  };
+
+  enum class TitlebarEvent {
+    Double_Click,
+    Middle_Click,
+  };
+
+  /**
+   * Get system defined action for titlebar events.
+   */
+  static TitlebarAction GetTitlebarAction(TitlebarEvent aEvent);
+
+  /**
+   * The millisecond to mask password value.
+   * This value is only valid when GetEchoPassword() returns true.
+   */
+  static uint32_t GetPasswordMaskDelay();
+
+  /** Gets theme information for about:support */
+  static void GetThemeInfo(nsACString&);
+
+  /**
+   * When system look and feel is changed, Refresh() must be called.  Then,
+   * cached data would be released.
+   */
+  static void Refresh();
+
+  /**
+   * GTK's initialization code can't be run off main thread, call this
+   * if you plan on using LookAndFeel off main thread later.
+   *
+   * This initialized state may get reset due to theme changes, so it
+   * must be called prior to each potential off-main-thread LookAndFeel
+   * call, not just once.
+   */
+  static void NativeInit();
+
+  static void SetData(widget::FullLookAndFeel&& aTables);
+  static void NotifyChangedAllWindows(widget::ThemeChangeKind);
+  static bool HasPendingGlobalThemeChange() { return sGlobalThemeChanged; }
+  static void HandleGlobalThemeChange() {
+    if (MOZ_UNLIKELY(HasPendingGlobalThemeChange())) {
+      DoHandleGlobalThemeChange();
+    }
+  }
+
+ protected:
+  static void DoHandleGlobalThemeChange();
+  // Set to true when ThemeChanged needs to be called on mTheme (and other
+  // global LookAndFeel.  This is used because mTheme is a service, so there's
+  // no need to notify it from more than one prescontext.
+  static bool sGlobalThemeChanged;
+};
+
+}  // namespace mozilla
+
+// ---------------------------------------------------------------------
+//  Special colors for ColorID::IME* and ColorID::SpellCheckerUnderline
+// ---------------------------------------------------------------------
+
+// For background color only.
+constexpr nscolor NS_TRANSPARENT = NS_RGBA(0x01, 0x00, 0x00, 0x00);
+// For foreground color only.
+constexpr nscolor NS_SAME_AS_FOREGROUND_COLOR = NS_RGBA(0x02, 0x00, 0x00, 0x00);
+constexpr nscolor NS_40PERCENT_FOREGROUND_COLOR =
+    NS_RGBA(0x03, 0x00, 0x00, 0x00);
+
+#define NS_IS_SELECTION_SPECIAL_COLOR(c)                          \
+  ((c) == NS_TRANSPARENT || (c) == NS_SAME_AS_FOREGROUND_COLOR || \
+   (c) == NS_40PERCENT_FOREGROUND_COLOR)
+
+// ------------------------------------------
+//  Bits for IntID::AlertNotificationOrigin
+// ------------------------------------------
+
+#define NS_ALERT_HORIZONTAL 1
+#define NS_ALERT_LEFT 2
+#define NS_ALERT_TOP 4
+
+#endif /* __LookAndFeel */
diff --git a/widget/LookAndFeelTypes.ipdlh b/widget/LookAndFeelTypes.ipdlh
new file mode 100644
index 0000000000..73ad01e16a
--- /dev/null
+++ b/widget/LookAndFeelTypes.ipdlh
@@ -0,0 +1,59 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=99: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+using nscolor from "nsColor.h";
+
+namespace mozilla {
+namespace widget {
+
+[Comparable] struct LookAndFeelFont {
+    bool haveFont;
+    nsString name;
+    float size;
+    float weight;
+    bool italic;
+};
+
+/**
+ * The format allows for some compression compared with having fixed
+ * length arrays for each value type and some indication of whether
+ * a value is present.  This is because not all values are present on
+ * a given platform, and because there is also substantial repetition
+ * of specific values.
+ *
+ * Each of ints, floats, colors, and fonts is an array that stores the
+ * unique values that occur in the LookAndFeel.  intMap, floatMap,
+ * colorMap, and fontMap map from value IDs (LookAndFeel::IntID, etc.)
+ * to indexes into the value arrays.  The map arrays are of fixed
+ * length, determined by the maximum ID value.  If a value for a
+ * particular ID is not present, the entry in the map is set to -1.
+ */
+struct LookAndFeelTables {
+    int32_t[] ints;
+    float[] floats;
+    LookAndFeelFont[] fonts;
+    nscolor[] lightColors;
+    nscolor[] darkColors;
+
+    uint8_t[] intMap;
+    uint8_t[] floatMap;
+    uint8_t[] fontMap;
+    uint8_t[] lightColorMap;
+    uint8_t[] darkColorMap;
+
+    uint16_t passwordChar;
+    bool passwordEcho;
+};
+
+/**
+ * Stores the entirety of a LookAndFeel's data.
+ */
+struct FullLookAndFeel {
+    LookAndFeelTables tables;
+};
+
+} // namespace widget
+} // namespace mozilla
diff --git a/widget/MediaKeysEventSourceFactory.h b/widget/MediaKeysEventSourceFactory.h
new file mode 100644
index 0000000000..6e913dde22
--- /dev/null
+++ b/widget/MediaKeysEventSourceFactory.h
@@ -0,0 +1,24 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_MEDIAKEYSEVENTSOURCEFACTORY_H_
+#define WIDGET_MEDIAKEYSEVENTSOURCEFACTORY_H_
+
+namespace mozilla {
+namespace dom {
+class MediaControlKeySource;
+}  // namespace dom
+}  // namespace mozilla
+
+namespace mozilla {
+namespace widget {
+
+// This function declaration is used to create a media keys event source on
+// different platforms, each platform should have their own implementation.
+extern mozilla::dom::MediaControlKeySource* CreateMediaControlKeySource();
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/MiscEvents.h b/widget/MiscEvents.h
new file mode 100644
index 0000000000..44c9d771e2
--- /dev/null
+++ b/widget/MiscEvents.h
@@ -0,0 +1,150 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_MiscEvents_h__
+#define mozilla_MiscEvents_h__
+
+#include <stdint.h>
+
+#include "mozilla/BasicEvents.h"
+#include "mozilla/Maybe.h"
+#include "nsCOMPtr.h"
+#include "nsAtom.h"
+#include "nsGkAtoms.h"
+#include "nsITransferable.h"
+#include "nsString.h"
+
+namespace mozilla {
+
+namespace dom {
+class PBrowserParent;
+class PBrowserChild;
+}  // namespace dom
+
+/******************************************************************************
+ * mozilla::WidgetContentCommandEvent
+ ******************************************************************************/
+
+class WidgetContentCommandEvent : public WidgetGUIEvent {
+ public:
+  virtual WidgetContentCommandEvent* AsContentCommandEvent() override {
+    return this;
+  }
+
+  WidgetContentCommandEvent(bool aIsTrusted, EventMessage aMessage,
+                            nsIWidget* aWidget, bool aOnlyEnabledCheck = false)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget,
+                       eContentCommandEventClass),
+        mOnlyEnabledCheck(aOnlyEnabledCheck),
+        mSucceeded(false),
+        mIsEnabled(false) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    // This event isn't an internal event of any DOM event.
+    NS_ASSERTION(!IsAllowedToDispatchDOMEvent(),
+                 "WidgetQueryContentEvent needs to support Duplicate()");
+    MOZ_CRASH("WidgetQueryContentEvent doesn't support Duplicate()");
+    return nullptr;
+  }
+
+  // eContentCommandInsertText
+  mozilla::Maybe<nsString> mString;  // [in]
+
+  // eContentCommandPasteTransferable
+  nsCOMPtr<nsITransferable> mTransferable;  // [in]
+
+  // eContentCommandScroll
+  // for mScroll.mUnit
+  enum { eCmdScrollUnit_Line, eCmdScrollUnit_Page, eCmdScrollUnit_Whole };
+
+  struct ScrollInfo {
+    ScrollInfo()
+        : mAmount(0), mUnit(eCmdScrollUnit_Line), mIsHorizontal(false) {}
+
+    int32_t mAmount;     // [in]
+    uint8_t mUnit;       // [in]
+    bool mIsHorizontal;  // [in]
+  } mScroll;
+
+  bool mOnlyEnabledCheck;  // [in]
+
+  bool mSucceeded;  // [out]
+  bool mIsEnabled;  // [out]
+
+  void AssignContentCommandEventData(const WidgetContentCommandEvent& aEvent,
+                                     bool aCopyTargets) {
+    AssignGUIEventData(aEvent, aCopyTargets);
+
+    mString = aEvent.mString;
+    mScroll = aEvent.mScroll;
+    mOnlyEnabledCheck = aEvent.mOnlyEnabledCheck;
+    mSucceeded = aEvent.mSucceeded;
+    mIsEnabled = aEvent.mIsEnabled;
+  }
+};
+
+/******************************************************************************
+ * mozilla::WidgetCommandEvent
+ *
+ * This sends a command to chrome.  If you want to request what is performed
+ * in focused content, you should use WidgetContentCommandEvent instead.
+ *
+ * XXX Should be |WidgetChromeCommandEvent|?
+ ******************************************************************************/
+
+class WidgetCommandEvent : public WidgetGUIEvent {
+ public:
+  virtual WidgetCommandEvent* AsCommandEvent() override { return this; }
+
+ protected:
+  WidgetCommandEvent(bool aIsTrusted, nsAtom* aEventType, nsAtom* aCommand,
+                     nsIWidget* aWidget, const WidgetEventTime* aTime = nullptr)
+      : WidgetGUIEvent(aIsTrusted, eUnidentifiedEvent, aWidget,
+                       eCommandEventClass, aTime),
+        mCommand(aCommand) {
+    mSpecifiedEventType = aEventType;
+  }
+
+ public:
+  /**
+   * Constructor to initialize an app command.  This is the only case to
+   * initialize this class as a command in C++ stack.
+   */
+  WidgetCommandEvent(bool aIsTrusted, nsAtom* aCommand, nsIWidget* aWidget,
+                     const WidgetEventTime* aTime = nullptr)
+      : WidgetCommandEvent(aIsTrusted, nsGkAtoms::onAppCommand, aCommand,
+                           aWidget, aTime) {}
+
+  /**
+   * Constructor to initialize as internal event of dom::CommandEvent.
+   */
+  WidgetCommandEvent()
+      : WidgetCommandEvent(false, nullptr, nullptr, nullptr, nullptr) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eCommandEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetCommandEvent* result = new WidgetCommandEvent(
+        false, mSpecifiedEventType, mCommand, nullptr, this);
+    result->AssignCommandEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  RefPtr<nsAtom> mCommand;
+
+  // XXX Not tested by test_assign_event_data.html
+  void AssignCommandEventData(const WidgetCommandEvent& aEvent,
+                              bool aCopyTargets) {
+    AssignGUIEventData(aEvent, aCopyTargets);
+
+    // mCommand must have been initialized with the constructor.
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_MiscEvents_h__
diff --git a/widget/MouseEvents.h b/widget/MouseEvents.h
new file mode 100644
index 0000000000..d29b406524
--- /dev/null
+++ b/widget/MouseEvents.h
@@ -0,0 +1,812 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_MouseEvents_h__
+#define mozilla_MouseEvents_h__
+
+#include <stdint.h>
+
+#include "mozilla/BasicEvents.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/MathAlgorithms.h"
+#include "mozilla/dom/DataTransfer.h"
+#include "mozilla/ipc/IPCForwards.h"
+#include "nsCOMPtr.h"
+
+namespace mozilla {
+
+namespace dom {
+class PBrowserParent;
+class PBrowserChild;
+class PBrowserBridgeParent;
+}  // namespace dom
+
+class WidgetPointerEvent;
+}  // namespace mozilla
+
+namespace mozilla {
+class WidgetPointerEventHolder final {
+ public:
+  nsTArray<WidgetPointerEvent> mEvents;
+  NS_INLINE_DECL_REFCOUNTING(WidgetPointerEventHolder)
+
+ private:
+  virtual ~WidgetPointerEventHolder() = default;
+};
+
+/******************************************************************************
+ * mozilla::WidgetPointerHelper
+ ******************************************************************************/
+
+class WidgetPointerHelper {
+ public:
+  uint32_t pointerId;
+  int32_t tiltX;
+  int32_t tiltY;
+  int32_t twist;
+  float tangentialPressure;
+  bool convertToPointer;
+  RefPtr<WidgetPointerEventHolder> mCoalescedWidgetEvents;
+
+  WidgetPointerHelper()
+      : pointerId(0),
+        tiltX(0),
+        tiltY(0),
+        twist(0),
+        tangentialPressure(0),
+        convertToPointer(true) {}
+
+  WidgetPointerHelper(uint32_t aPointerId, uint32_t aTiltX, uint32_t aTiltY,
+                      uint32_t aTwist = 0, float aTangentialPressure = 0)
+      : pointerId(aPointerId),
+        tiltX(aTiltX),
+        tiltY(aTiltY),
+        twist(aTwist),
+        tangentialPressure(aTangentialPressure),
+        convertToPointer(true) {}
+
+  explicit WidgetPointerHelper(const WidgetPointerHelper& aHelper) = default;
+
+  void AssignPointerHelperData(const WidgetPointerHelper& aEvent,
+                               bool aCopyCoalescedEvents = false) {
+    pointerId = aEvent.pointerId;
+    tiltX = aEvent.tiltX;
+    tiltY = aEvent.tiltY;
+    twist = aEvent.twist;
+    tangentialPressure = aEvent.tangentialPressure;
+    convertToPointer = aEvent.convertToPointer;
+    if (aCopyCoalescedEvents) {
+      mCoalescedWidgetEvents = aEvent.mCoalescedWidgetEvents;
+    }
+  }
+};
+
+/******************************************************************************
+ * mozilla::WidgetMouseEventBase
+ ******************************************************************************/
+
+class WidgetMouseEventBase : public WidgetInputEvent {
+ private:
+  friend class dom::PBrowserParent;
+  friend class dom::PBrowserChild;
+  friend class dom::PBrowserBridgeParent;
+  ALLOW_DEPRECATED_READPARAM
+
+ protected:
+  WidgetMouseEventBase()
+      : mPressure(0),
+        mButton(0),
+        mButtons(0),
+        mInputSource(/* MouseEvent_Binding::MOZ_SOURCE_MOUSE = */ 1) {}
+  // Including MouseEventBinding.h here leads to an include loop, so
+  // we have to hardcode MouseEvent_Binding::MOZ_SOURCE_MOUSE.
+
+  WidgetMouseEventBase(bool aIsTrusted, EventMessage aMessage,
+                       nsIWidget* aWidget, EventClassID aEventClassID,
+                       const WidgetEventTime* aTime = nullptr)
+      : WidgetInputEvent(aIsTrusted, aMessage, aWidget, aEventClassID, aTime),
+        mPressure(0),
+        mButton(0),
+        mButtons(0),
+        mInputSource(/* MouseEvent_Binding::MOZ_SOURCE_MOUSE = */ 1) {}
+  // Including MouseEventBinding.h here leads to an include loop, so
+  // we have to hardcode MouseEvent_Binding::MOZ_SOURCE_MOUSE.
+
+ public:
+  virtual WidgetMouseEventBase* AsMouseEventBase() override { return this; }
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_CRASH("WidgetMouseEventBase must not be most-subclass");
+  }
+
+  // Finger or touch pressure of event. It ranges between 0.0 and 1.0.
+  float mPressure;
+
+  // Pressed button ID of mousedown or mouseup event.
+  // This is set only when pressing a button causes the event.
+  int16_t mButton;
+
+  // Flags of all pressed buttons at the event fired.
+  // This is set at any mouse event, don't be confused with |mButton|.
+  int16_t mButtons;
+
+  // Possible values a in MouseEvent
+  uint16_t mInputSource;
+
+  bool IsLeftButtonPressed() const {
+    return !!(mButtons & MouseButtonsFlag::ePrimaryFlag);
+  }
+  bool IsRightButtonPressed() const {
+    return !!(mButtons & MouseButtonsFlag::eSecondaryFlag);
+  }
+  bool IsMiddleButtonPressed() const {
+    return !!(mButtons & MouseButtonsFlag::eMiddleFlag);
+  }
+  bool Is4thButtonPressed() const {
+    return !!(mButtons & MouseButtonsFlag::e4thFlag);
+  }
+  bool Is5thButtonPressed() const {
+    return !!(mButtons & MouseButtonsFlag::e5thFlag);
+  }
+
+  void AssignMouseEventBaseData(const WidgetMouseEventBase& aEvent,
+                                bool aCopyTargets) {
+    AssignInputEventData(aEvent, aCopyTargets);
+
+    mButton = aEvent.mButton;
+    mButtons = aEvent.mButtons;
+    mPressure = aEvent.mPressure;
+    mInputSource = aEvent.mInputSource;
+  }
+
+  /**
+   * Returns true if left click event.
+   */
+  bool IsLeftClickEvent() const {
+    return mMessage == eMouseClick && mButton == MouseButton::ePrimary;
+  }
+
+  /**
+   * Returns true if this event changes a button state to "pressed".
+   */
+  [[nodiscard]] bool IsPressingButton() const {
+    MOZ_ASSERT(IsTrusted());
+    if (mClass == eMouseEventClass) {
+      return mMessage == eMouseDown;
+    }
+    if (mButton == MouseButton::eNotPressed) {
+      return false;
+    }
+    // If this is an ePointerDown event whose mButton is not "not pressed", this
+    // is a button pressing event.
+    if (mMessage == ePointerDown) {
+      return true;
+    }
+    // If 2 or more buttons are pressed at same time, they are sent with
+    // pointermove rather than pointerdown.  Therefore, let's check whether
+    // mButtons contains the proper flag for the pressing button.
+    const bool buttonsContainButton = !!(
+        mButtons & MouseButtonsFlagToChange(static_cast<MouseButton>(mButton)));
+    return mMessage == ePointerMove && buttonsContainButton;
+  }
+
+  /**
+   * Returns true if this event changes a button state to "released".
+   */
+  [[nodiscard]] bool IsReleasingButton() const {
+    MOZ_ASSERT(IsTrusted());
+    if (mClass == eMouseEventClass) {
+      return mMessage == eMouseUp;
+    }
+    if (mButton == MouseButton::eNotPressed) {
+      return false;
+    }
+    // If this is an ePointerUp event whose mButton is not "not pressed", this
+    // is a button release event.
+    if (mMessage == ePointerUp) {
+      return true;
+    }
+    // If the releasing button is not the last button of pressing buttons, web
+    // apps notified by pointermove rather than pointerup.  Therefore, let's
+    // check whether mButtons loses the proper flag for the releasing button.
+    const bool buttonsLoseTheButton = !(
+        mButtons & MouseButtonsFlagToChange(static_cast<MouseButton>(mButton)));
+    return mMessage == ePointerMove && buttonsLoseTheButton;
+  }
+
+  /**
+   * Returns true if the input source supports hover state like a mouse.
+   */
+  [[nodiscard]] bool InputSourceSupportsHover() const;
+};
+
+/******************************************************************************
+ * mozilla::WidgetMouseEvent
+ ******************************************************************************/
+
+class WidgetMouseEvent : public WidgetMouseEventBase,
+                         public WidgetPointerHelper {
+ private:
+  friend class dom::PBrowserParent;
+  friend class dom::PBrowserChild;
+  friend class dom::PBrowserBridgeParent;
+  ALLOW_DEPRECATED_READPARAM
+
+ public:
+  typedef bool ReasonType;
+  enum Reason : ReasonType { eReal, eSynthesized };
+
+  typedef uint8_t ContextMenuTriggerType;
+  enum ContextMenuTrigger : ContextMenuTriggerType {
+    eNormal,
+    eContextMenuKey,
+    eControlClick
+  };
+
+  typedef uint8_t ExitFromType;
+  enum ExitFrom : ExitFromType {
+    ePlatformChild,
+    ePlatformTopLevel,
+    ePuppet,
+    ePuppetParentToPuppetChild
+  };
+
+ protected:
+  WidgetMouseEvent()
+      : mReason(eReal),
+        mContextMenuTrigger(eNormal),
+        mClickCount(0),
+        mIgnoreRootScrollFrame(false),
+        mClickEventPrevented(false) {}
+
+  WidgetMouseEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
+                   EventClassID aEventClassID, Reason aReason,
+                   const WidgetEventTime* aTime = nullptr)
+      : WidgetMouseEventBase(aIsTrusted, aMessage, aWidget, aEventClassID,
+                             aTime),
+        mReason(aReason),
+        mContextMenuTrigger(eNormal),
+        mClickCount(0),
+        mIgnoreRootScrollFrame(false),
+        mClickEventPrevented(false) {}
+
+#ifdef DEBUG
+  void AssertContextMenuEventButtonConsistency() const;
+#endif
+
+ public:
+  virtual WidgetMouseEvent* AsMouseEvent() override { return this; }
+
+  WidgetMouseEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
+                   Reason aReason,
+                   ContextMenuTrigger aContextMenuTrigger = eNormal,
+                   const WidgetEventTime* aTime = nullptr)
+      : WidgetMouseEventBase(aIsTrusted, aMessage, aWidget, eMouseEventClass,
+                             aTime),
+        mReason(aReason),
+        mContextMenuTrigger(aContextMenuTrigger),
+        mClickCount(0),
+        mIgnoreRootScrollFrame(false),
+        mClickEventPrevented(false) {
+    if (aMessage == eContextMenu) {
+      mButton = (mContextMenuTrigger == eNormal) ? MouseButton::eSecondary
+                                                 : MouseButton::ePrimary;
+    }
+  }
+
+#ifdef DEBUG
+  virtual ~WidgetMouseEvent() { AssertContextMenuEventButtonConsistency(); }
+#endif
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eMouseEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetMouseEvent* result = new WidgetMouseEvent(
+        false, mMessage, nullptr, mReason, mContextMenuTrigger, this);
+    result->AssignMouseEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  // If during mouseup handling we detect that click event might need to be
+  // dispatched, this is setup to be the target of the click event.
+  nsCOMPtr<dom::EventTarget> mClickTarget;
+
+  // mReason indicates the reason why the event is fired:
+  // - Representing mouse operation.
+  // - Synthesized for emulating mousemove event when the content under the
+  //   mouse cursor is scrolled.
+  Reason mReason;
+
+  // mContextMenuTrigger is valid only when mMessage is eContextMenu.
+  // This indicates if the context menu event is caused by context menu key or
+  // other reasons (typically, a click of right mouse button).
+  ContextMenuTrigger mContextMenuTrigger;
+
+  // mExitFrom contains a value only when mMessage is eMouseExitFromWidget.
+  // This indicates if the mouse cursor exits from a top level platform widget,
+  // a child widget or a puppet widget.
+  Maybe<ExitFrom> mExitFrom;
+
+  // mClickCount may be non-zero value when mMessage is eMouseDown, eMouseUp,
+  // eMouseClick or eMouseDoubleClick. The number is count of mouse clicks.
+  // Otherwise, this must be 0.
+  uint32_t mClickCount;
+
+  // Whether the event should ignore scroll frame bounds during dispatch.
+  bool mIgnoreRootScrollFrame;
+
+  // Whether the event shouldn't cause click event.
+  bool mClickEventPrevented;
+
+  void AssignMouseEventData(const WidgetMouseEvent& aEvent, bool aCopyTargets) {
+    AssignMouseEventBaseData(aEvent, aCopyTargets);
+    AssignPointerHelperData(aEvent, /* aCopyCoalescedEvents */ true);
+
+    mExitFrom = aEvent.mExitFrom;
+    mClickCount = aEvent.mClickCount;
+    mIgnoreRootScrollFrame = aEvent.mIgnoreRootScrollFrame;
+    mClickEventPrevented = aEvent.mClickEventPrevented;
+  }
+
+  /**
+   * Returns true if the event is a context menu event caused by key.
+   */
+  bool IsContextMenuKeyEvent() const {
+    return mMessage == eContextMenu && mContextMenuTrigger == eContextMenuKey;
+  }
+
+  /**
+   * Returns true if the event is a real mouse event.  Otherwise, i.e., it's
+   * a synthesized event by scroll or something, returns false.
+   */
+  bool IsReal() const { return mReason == eReal; }
+
+  /**
+   * Returns true if middle click paste is enabled.
+   */
+  static bool IsMiddleClickPasteEnabled();
+};
+
+/******************************************************************************
+ * mozilla::WidgetDragEvent
+ ******************************************************************************/
+
+class WidgetDragEvent : public WidgetMouseEvent {
+ private:
+  friend class mozilla::dom::PBrowserParent;
+  friend class mozilla::dom::PBrowserChild;
+  ALLOW_DEPRECATED_READPARAM
+
+ protected:
+  WidgetDragEvent()
+      : mUserCancelled(false),
+        mDefaultPreventedOnContent(false),
+        mInHTMLEditorEventListener(false) {}
+
+ public:
+  virtual WidgetDragEvent* AsDragEvent() override { return this; }
+
+  WidgetDragEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
+                  const WidgetEventTime* aTime = nullptr)
+      : WidgetMouseEvent(aIsTrusted, aMessage, aWidget, eDragEventClass, eReal,
+                         aTime),
+        mUserCancelled(false),
+        mDefaultPreventedOnContent(false),
+        mInHTMLEditorEventListener(false) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eDragEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetDragEvent* result =
+        new WidgetDragEvent(false, mMessage, nullptr, this);
+    result->AssignDragEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  // The dragging data.
+  nsCOMPtr<dom::DataTransfer> mDataTransfer;
+
+  // If this is true, user has cancelled the drag operation.
+  bool mUserCancelled;
+  // If this is true, the drag event's preventDefault() is called on content.
+  bool mDefaultPreventedOnContent;
+  // If this event is currently being handled by HTMLEditorEventListener.
+  bool mInHTMLEditorEventListener;
+
+  // XXX Not tested by test_assign_event_data.html
+  void AssignDragEventData(const WidgetDragEvent& aEvent, bool aCopyTargets) {
+    AssignMouseEventData(aEvent, aCopyTargets);
+
+    mDataTransfer = aEvent.mDataTransfer;
+    // XXX mUserCancelled isn't copied, is this intentionally?
+    mUserCancelled = false;
+    mDefaultPreventedOnContent = aEvent.mDefaultPreventedOnContent;
+    // XXX mInHTMLEditorEventListener isn't copied, is this intentionally?
+    mInHTMLEditorEventListener = false;
+  }
+
+  bool CanConvertToInputData() const {
+    return mMessage == eDragStart || mMessage == eDragEnd;
+  }
+
+  /**
+   * Should be called before dispatching the DOM tree if this event is
+   * synthesized for tests because drop effect is initialized before
+   * dispatching from widget if it's not synthesized event, but synthesized
+   * events are not initialized in the path.
+   */
+  void InitDropEffectForTests();
+};
+
+/******************************************************************************
+ * mozilla::WidgetMouseScrollEvent
+ *
+ * This is used for legacy DOM mouse scroll events, i.e.,
+ * DOMMouseScroll and MozMousePixelScroll event.  These events are NOT hanbled
+ * by ESM even if widget dispatches them.  Use new WidgetWheelEvent instead.
+ ******************************************************************************/
+
+class WidgetMouseScrollEvent : public WidgetMouseEventBase {
+ private:
+  WidgetMouseScrollEvent() : mDelta(0), mIsHorizontal(false) {}
+
+ public:
+  virtual WidgetMouseScrollEvent* AsMouseScrollEvent() override { return this; }
+
+  WidgetMouseScrollEvent(bool aIsTrusted, EventMessage aMessage,
+                         nsIWidget* aWidget,
+                         const WidgetEventTime* aTime = nullptr)
+      : WidgetMouseEventBase(aIsTrusted, aMessage, aWidget,
+                             eMouseScrollEventClass, aTime),
+        mDelta(0),
+        mIsHorizontal(false) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eMouseScrollEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetMouseScrollEvent* result =
+        new WidgetMouseScrollEvent(false, mMessage, nullptr, this);
+    result->AssignMouseScrollEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  // The delta value of mouse scroll event.
+  // If the event message is eLegacyMouseLineOrPageScroll, the value indicates
+  // scroll amount in lines.  However, if the value is
+  // UIEvent::SCROLL_PAGE_UP or UIEvent::SCROLL_PAGE_DOWN, the
+  // value inducates one page scroll.  If the event message is
+  // eLegacyMousePixelScroll, the value indicates scroll amount in pixels.
+  int32_t mDelta;
+
+  // If this is true, it may cause to scroll horizontally.
+  // Otherwise, vertically.
+  bool mIsHorizontal;
+
+  void AssignMouseScrollEventData(const WidgetMouseScrollEvent& aEvent,
+                                  bool aCopyTargets) {
+    AssignMouseEventBaseData(aEvent, aCopyTargets);
+
+    mDelta = aEvent.mDelta;
+    mIsHorizontal = aEvent.mIsHorizontal;
+  }
+};
+
+/******************************************************************************
+ * mozilla::WidgetWheelEvent
+ ******************************************************************************/
+
+class WidgetWheelEvent : public WidgetMouseEventBase {
+ private:
+  friend class mozilla::dom::PBrowserParent;
+  friend class mozilla::dom::PBrowserChild;
+  ALLOW_DEPRECATED_READPARAM
+
+  WidgetWheelEvent()
+      : mDeltaX(0.0),
+        mDeltaY(0.0),
+        mDeltaZ(0.0),
+        mOverflowDeltaX(0.0),
+        mOverflowDeltaY(0.0)
+        // Including WheelEventBinding.h here leads to an include loop, so
+        // we have to hardcode WheelEvent_Binding::DOM_DELTA_PIXEL.
+        ,
+        mDeltaMode(/* WheelEvent_Binding::DOM_DELTA_PIXEL = */ 0),
+        mLineOrPageDeltaX(0),
+        mLineOrPageDeltaY(0),
+        mScrollType(SCROLL_DEFAULT),
+        mCustomizedByUserPrefs(false),
+        mMayHaveMomentum(false),
+        mIsMomentum(false),
+        mIsNoLineOrPageDelta(false),
+        mViewPortIsOverscrolled(false),
+        mCanTriggerSwipe(false),
+        mAllowToOverrideSystemScrollSpeed(false),
+        mDeltaValuesHorizontalizedForDefaultHandler(false) {}
+
+ public:
+  virtual WidgetWheelEvent* AsWheelEvent() override { return this; }
+
+  WidgetWheelEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
+                   const WidgetEventTime* aTime = nullptr)
+      : WidgetMouseEventBase(aIsTrusted, aMessage, aWidget, eWheelEventClass,
+                             aTime),
+        mDeltaX(0.0),
+        mDeltaY(0.0),
+        mDeltaZ(0.0),
+        mOverflowDeltaX(0.0),
+        mOverflowDeltaY(0.0)
+        // Including WheelEventBinding.h here leads to an include loop, so
+        // we have to hardcode WheelEvent_Binding::DOM_DELTA_PIXEL.
+        ,
+        mDeltaMode(/* WheelEvent_Binding::DOM_DELTA_PIXEL = */ 0),
+        mLineOrPageDeltaX(0),
+        mLineOrPageDeltaY(0),
+        mScrollType(SCROLL_DEFAULT),
+        mCustomizedByUserPrefs(false),
+        mMayHaveMomentum(false),
+        mIsMomentum(false),
+        mIsNoLineOrPageDelta(false),
+        mViewPortIsOverscrolled(false),
+        mCanTriggerSwipe(false),
+        mAllowToOverrideSystemScrollSpeed(true),
+        mDeltaValuesHorizontalizedForDefaultHandler(false) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eWheelEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetWheelEvent* result =
+        new WidgetWheelEvent(false, mMessage, nullptr, this);
+    result->AssignWheelEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  // Scroll gestures that start at the edge of the scrollable range can result
+  // in a swipe gesture. For the first wheel event of such a gesture, call
+  // TriggersSwipe() after the event has been processed in order to find out
+  // whether a swipe should be started.
+  bool TriggersSwipe() const {
+    return mCanTriggerSwipe && mViewPortIsOverscrolled &&
+           this->mOverflowDeltaX != 0.0;
+  }
+
+  // NOTE: mDeltaX, mDeltaY and mDeltaZ may be customized by
+  //       mousewheel.*.delta_multiplier_* prefs which are applied by
+  //       EventStateManager.  So, after widget dispatches this event,
+  //       these delta values may have different values than before.
+  double mDeltaX;
+  double mDeltaY;
+  double mDeltaZ;
+
+  // The mousewheel tick counts.
+  double mWheelTicksX = 0.0;
+  double mWheelTicksY = 0.0;
+
+  enum class DeltaModeCheckingState : uint8_t {
+    // Neither deltaMode nor the delta values have been accessed.
+    Unknown,
+    // The delta values have been accessed, without checking deltaMode first.
+    Unchecked,
+    // The deltaMode has been checked.
+    Checked,
+  };
+
+  // For compat reasons, we might expose a DOM_DELTA_LINE event as
+  // DOM_DELTA_PIXEL instead. Whether we do that depends on whether the event
+  // has been asked for the deltaMode before the deltas. If it has, we assume
+  // that the page will correctly handle DOM_DELTA_LINE. This variable tracks
+  // that state. See bug 1392460.
+  DeltaModeCheckingState mDeltaModeCheckingState =
+      DeltaModeCheckingState::Unknown;
+
+  // The amount of scrolling per line or page, without accounting for mouse
+  // wheel transactions etc.
+  //
+  // Computed by EventStateManager::DeltaAccumulator::InitLineOrPageDelta.
+  nsSize mScrollAmount;
+
+  // overflowed delta values for scroll, these values are set by
+  // EventStateManger.  If the default action of the wheel event isn't scroll,
+  // these values are always zero.  Otherwise, remaining delta values which are
+  // not used by scroll are set.
+  // NOTE: mDeltaX, mDeltaY and mDeltaZ may be modified by EventStateManager.
+  //       However, mOverflowDeltaX and mOverflowDeltaY indicate unused original
+  //       delta values which are not applied the delta_multiplier prefs.
+  //       So, if widget wanted to know the actual direction to be scrolled,
+  //       it would need to check the mDeltaX and mDeltaY.
+  double mOverflowDeltaX;
+  double mOverflowDeltaY;
+
+  // Should be one of WheelEvent_Binding::DOM_DELTA_*
+  uint32_t mDeltaMode;
+
+  // If widget sets mLineOrPageDelta, EventStateManager will dispatch
+  // eLegacyMouseLineOrPageScroll event for compatibility.  Note that the delta
+  // value means pages if the mDeltaMode is DOM_DELTA_PAGE, otherwise, lines.
+  int32_t mLineOrPageDeltaX;
+  int32_t mLineOrPageDeltaY;
+
+  // When the default action for an wheel event is moving history or zooming,
+  // need to chose a delta value for doing it.
+  int32_t GetPreferredIntDelta() {
+    if (!mLineOrPageDeltaX && !mLineOrPageDeltaY) {
+      return 0;
+    }
+    if (mLineOrPageDeltaY && !mLineOrPageDeltaX) {
+      return mLineOrPageDeltaY;
+    }
+    if (mLineOrPageDeltaX && !mLineOrPageDeltaY) {
+      return mLineOrPageDeltaX;
+    }
+    if ((mLineOrPageDeltaX < 0 && mLineOrPageDeltaY > 0) ||
+        (mLineOrPageDeltaX > 0 && mLineOrPageDeltaY < 0)) {
+      return 0;  // We cannot guess the answer in this case.
+    }
+    return (Abs(mLineOrPageDeltaX) > Abs(mLineOrPageDeltaY))
+               ? mLineOrPageDeltaX
+               : mLineOrPageDeltaY;
+  }
+
+  // Scroll type
+  // The default value is SCROLL_DEFAULT, which means EventStateManager will
+  // select preferred scroll type automatically.
+  enum ScrollType : uint8_t {
+    SCROLL_DEFAULT,
+    SCROLL_SYNCHRONOUSLY,
+    SCROLL_ASYNCHRONOUSLY,
+    SCROLL_SMOOTHLY
+  };
+  ScrollType mScrollType;
+
+  // If the delta values are computed from prefs, this value is true.
+  // Otherwise, i.e., they are computed from native events, false.
+  bool mCustomizedByUserPrefs;
+
+  // true if the momentum events directly tied to this event may follow it.
+  bool mMayHaveMomentum;
+  // true if the event is caused by momentum.
+  bool mIsMomentum;
+
+  // If device event handlers don't know when they should set mLineOrPageDeltaX
+  // and mLineOrPageDeltaY, this is true.  Otherwise, false.
+  // If mIsNoLineOrPageDelta is true, ESM will generate
+  // eLegacyMouseLineOrPageScroll events when accumulated delta values reach
+  // a line height.
+  bool mIsNoLineOrPageDelta;
+
+  // Whether or not the parent of the currently overscrolled frame is the
+  // ViewPort. This is false in situations when an element on the page is being
+  // overscrolled (such as a text field), but true when the 'page' is being
+  // overscrolled.
+  bool mViewPortIsOverscrolled;
+
+  // The wheel event can trigger a swipe to start if it's overscrolling the
+  // viewport.
+  bool mCanTriggerSwipe;
+
+  // If mAllowToOverrideSystemScrollSpeed is true, the scroll speed may be
+  // overridden.  Otherwise, the scroll speed won't be overridden even if
+  // it's enabled by the pref.
+  bool mAllowToOverrideSystemScrollSpeed;
+
+  // After the event's default action handler has adjusted its delta's values
+  // for horizontalizing a vertical wheel scroll, this variable will be set to
+  // true.
+  bool mDeltaValuesHorizontalizedForDefaultHandler;
+
+  void AssignWheelEventData(const WidgetWheelEvent& aEvent, bool aCopyTargets) {
+    AssignMouseEventBaseData(aEvent, aCopyTargets);
+
+    mDeltaX = aEvent.mDeltaX;
+    mDeltaY = aEvent.mDeltaY;
+    mDeltaZ = aEvent.mDeltaZ;
+    mDeltaMode = aEvent.mDeltaMode;
+    mScrollAmount = aEvent.mScrollAmount;
+    mCustomizedByUserPrefs = aEvent.mCustomizedByUserPrefs;
+    mMayHaveMomentum = aEvent.mMayHaveMomentum;
+    mIsMomentum = aEvent.mIsMomentum;
+    mIsNoLineOrPageDelta = aEvent.mIsNoLineOrPageDelta;
+    mLineOrPageDeltaX = aEvent.mLineOrPageDeltaX;
+    mLineOrPageDeltaY = aEvent.mLineOrPageDeltaY;
+    mScrollType = aEvent.mScrollType;
+    mOverflowDeltaX = aEvent.mOverflowDeltaX;
+    mOverflowDeltaY = aEvent.mOverflowDeltaY;
+    mViewPortIsOverscrolled = aEvent.mViewPortIsOverscrolled;
+    mCanTriggerSwipe = aEvent.mCanTriggerSwipe;
+    mAllowToOverrideSystemScrollSpeed =
+        aEvent.mAllowToOverrideSystemScrollSpeed;
+    mDeltaValuesHorizontalizedForDefaultHandler =
+        aEvent.mDeltaValuesHorizontalizedForDefaultHandler;
+  }
+
+  // System scroll speed settings may be too slow at using Gecko.  In such
+  // case, we should override the scroll speed computed with system settings.
+  // Following methods return preferred delta values which are multiplied by
+  // factors specified by prefs.  If system scroll speed shouldn't be
+  // overridden (e.g., this feature is disabled by pref), they return raw
+  // delta values.
+  double OverriddenDeltaX() const;
+  double OverriddenDeltaY() const;
+
+  // Compute the overridden delta value.  This may be useful for suppressing
+  // too fast scroll by system scroll speed overriding when widget sets
+  // mAllowToOverrideSystemScrollSpeed.
+  static double ComputeOverriddenDelta(double aDelta, bool aIsForVertical);
+
+ private:
+  static bool sInitialized;
+  static bool sIsSystemScrollSpeedOverrideEnabled;
+  static int32_t sOverrideFactorX;
+  static int32_t sOverrideFactorY;
+  static void Initialize();
+};
+
+/******************************************************************************
+ * mozilla::WidgetPointerEvent
+ ******************************************************************************/
+
+class WidgetPointerEvent : public WidgetMouseEvent {
+  friend class mozilla::dom::PBrowserParent;
+  friend class mozilla::dom::PBrowserChild;
+  ALLOW_DEPRECATED_READPARAM
+
+ public:
+  virtual WidgetPointerEvent* AsPointerEvent() override { return this; }
+
+  WidgetPointerEvent(bool aIsTrusted, EventMessage aMsg, nsIWidget* w,
+                     const WidgetEventTime* aTime = nullptr)
+      : WidgetMouseEvent(aIsTrusted, aMsg, w, ePointerEventClass, eReal, aTime),
+        mWidth(1),
+        mHeight(1),
+        mIsPrimary(true),
+        mFromTouchEvent(false) {}
+
+  explicit WidgetPointerEvent(const WidgetMouseEvent& aEvent)
+      : WidgetMouseEvent(aEvent),
+        mWidth(1),
+        mHeight(1),
+        mIsPrimary(true),
+        mFromTouchEvent(false) {
+    mClass = ePointerEventClass;
+  }
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == ePointerEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetPointerEvent* result =
+        new WidgetPointerEvent(false, mMessage, nullptr, this);
+    result->AssignPointerEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  int32_t mWidth;
+  int32_t mHeight;
+  bool mIsPrimary;
+  bool mFromTouchEvent;
+
+  // XXX Not tested by test_assign_event_data.html
+  void AssignPointerEventData(const WidgetPointerEvent& aEvent,
+                              bool aCopyTargets) {
+    AssignMouseEventData(aEvent, aCopyTargets);
+
+    mWidth = aEvent.mWidth;
+    mHeight = aEvent.mHeight;
+    mIsPrimary = aEvent.mIsPrimary;
+    mFromTouchEvent = aEvent.mFromTouchEvent;
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_MouseEvents_h__
diff --git a/widget/NativeKeyBindingsType.h b/widget/NativeKeyBindingsType.h
new file mode 100644
index 0000000000..a5885a91ef
--- /dev/null
+++ b/widget/NativeKeyBindingsType.h
@@ -0,0 +1,19 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_NativeKeyBindingsType_h
+#define mozilla_NativeKeyBindingsType_h
+
+namespace mozilla {
+
+enum class NativeKeyBindingsType : uint8_t {
+  SingleLineEditor,  // <input type="text"> etc
+  MultiLineEditor,   // <textarea>
+  RichTextEditor,    // contenteditable or designMode
+};
+
+}  // namespace mozilla
+
+#endif  // #ifndef mozilla_NativeKeyBindings_h
diff --git a/widget/NativeKeyToDOMCodeName.h b/widget/NativeKeyToDOMCodeName.h
new file mode 100644
index 0000000000..7a819a9f3c
--- /dev/null
+++ b/widget/NativeKeyToDOMCodeName.h
@@ -0,0 +1,821 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This header file defines simple code mapping between native scancode or
+ * something and DOM code name index.
+ * You must define NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX macro before include
+ * this.
+ *
+ * It must have two arguments, (aNativeKey, aCodeNameIndex).
+ * aNativeKey is a scancode value or something (depends on the platform).
+ * aCodeNameIndex is the widget::CodeNameIndex value.
+ */
+
+// Windows
+#define CODE_MAP_WIN(aCPPCodeName, aNativeKey)
+// Mac OS X
+#define CODE_MAP_MAC(aCPPCodeName, aNativeKey)
+// GTK and Qt on Linux
+#define CODE_MAP_X11(aCPPCodeName, aNativeKey)
+// Android
+#define CODE_MAP_ANDROID(aCPPCodeName, aNativeKey)
+
+#if defined(XP_WIN)
+#  undef CODE_MAP_WIN
+// aNativeKey is scan code
+#  define CODE_MAP_WIN(aCPPCodeName, aNativeKey)     \
+    NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX(aNativeKey, \
+                                         CODE_NAME_INDEX_##aCPPCodeName)
+#elif defined(XP_MACOSX)
+#  undef CODE_MAP_MAC
+// aNativeKey is key code starting with kVK_.
+#  define CODE_MAP_MAC(aCPPCodeName, aNativeKey)     \
+    NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX(aNativeKey, \
+                                         CODE_NAME_INDEX_##aCPPCodeName)
+#elif defined(MOZ_WIDGET_GTK)
+#  undef CODE_MAP_X11
+// aNativeKey is hardware_keycode of GDKEvent or nativeScanCode of QKeyEvent.
+#  define CODE_MAP_X11(aCPPCodeName, aNativeKey)     \
+    NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX(aNativeKey, \
+                                         CODE_NAME_INDEX_##aCPPCodeName)
+#elif defined(ANDROID)
+#  undef CODE_MAP_ANDROID
+// aNativeKey is scan code
+#  define CODE_MAP_ANDROID(aCPPCodeName, aNativeKey) \
+    NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX(aNativeKey, \
+                                         CODE_NAME_INDEX_##aCPPCodeName)
+#endif
+
+// Writing system keys
+CODE_MAP_WIN(Backquote, 0x0029)
+CODE_MAP_MAC(Backquote, kVK_ANSI_Grave)
+CODE_MAP_X11(Backquote, 0x0031)
+CODE_MAP_ANDROID(Backquote, 0x0029)
+
+CODE_MAP_WIN(Backslash, 0x002B)
+CODE_MAP_MAC(Backslash, kVK_ANSI_Backslash)
+CODE_MAP_X11(Backslash, 0x0033)
+CODE_MAP_ANDROID(Backslash, 0x002B)
+
+CODE_MAP_WIN(Backspace, 0x000E)
+CODE_MAP_MAC(Backspace, kVK_Delete)
+CODE_MAP_X11(Backspace, 0x0016)
+CODE_MAP_ANDROID(Backspace, 0x000E)
+
+CODE_MAP_WIN(BracketLeft, 0x001A)
+CODE_MAP_MAC(BracketLeft, kVK_ANSI_LeftBracket)
+CODE_MAP_X11(BracketLeft, 0x0022)
+CODE_MAP_ANDROID(BracketLeft, 0x001A)
+
+CODE_MAP_WIN(BracketRight, 0x001B)
+CODE_MAP_MAC(BracketRight, kVK_ANSI_RightBracket)
+CODE_MAP_X11(BracketRight, 0x0023)
+CODE_MAP_ANDROID(BracketRight, 0x001B)
+
+CODE_MAP_WIN(Comma, 0x0033)
+CODE_MAP_MAC(Comma, kVK_ANSI_Comma)
+CODE_MAP_X11(Comma, 0x003B)
+CODE_MAP_ANDROID(Comma, 0x00033)
+
+CODE_MAP_WIN(Digit0, 0x000B)
+CODE_MAP_MAC(Digit0, kVK_ANSI_0)
+CODE_MAP_X11(Digit0, 0x0013)
+CODE_MAP_ANDROID(Digit0, 0x000B)
+
+CODE_MAP_WIN(Digit1, 0x0002)
+CODE_MAP_MAC(Digit1, kVK_ANSI_1)
+CODE_MAP_X11(Digit1, 0x000A)
+CODE_MAP_ANDROID(Digit1, 0x0002)
+
+CODE_MAP_WIN(Digit2, 0x0003)
+CODE_MAP_MAC(Digit2, kVK_ANSI_2)
+CODE_MAP_X11(Digit2, 0x000B)
+CODE_MAP_ANDROID(Digit2, 0x0003)
+
+CODE_MAP_WIN(Digit3, 0x0004)
+CODE_MAP_MAC(Digit3, kVK_ANSI_3)
+CODE_MAP_X11(Digit3, 0x000C)
+CODE_MAP_ANDROID(Digit3, 0x0004)
+
+CODE_MAP_WIN(Digit4, 0x0005)
+CODE_MAP_MAC(Digit4, kVK_ANSI_4)
+CODE_MAP_X11(Digit4, 0x000D)
+CODE_MAP_ANDROID(Digit4, 0x0005)
+
+CODE_MAP_WIN(Digit5, 0x0006)
+CODE_MAP_MAC(Digit5, kVK_ANSI_5)
+CODE_MAP_X11(Digit5, 0x000E)
+CODE_MAP_ANDROID(Digit5, 0x0006)
+
+CODE_MAP_WIN(Digit6, 0x0007)
+CODE_MAP_MAC(Digit6, kVK_ANSI_6)
+CODE_MAP_X11(Digit6, 0x000F)
+CODE_MAP_ANDROID(Digit6, 0x0007)
+
+CODE_MAP_WIN(Digit7, 0x0008)
+CODE_MAP_MAC(Digit7, kVK_ANSI_7)
+CODE_MAP_X11(Digit7, 0x0010)
+CODE_MAP_ANDROID(Digit7, 0x0008)
+
+CODE_MAP_WIN(Digit8, 0x0009)
+CODE_MAP_MAC(Digit8, kVK_ANSI_8)
+CODE_MAP_X11(Digit8, 0x0011)
+CODE_MAP_ANDROID(Digit8, 0x0009)
+
+CODE_MAP_WIN(Digit9, 0x000A)
+CODE_MAP_MAC(Digit9, kVK_ANSI_9)
+CODE_MAP_X11(Digit9, 0x0012)
+CODE_MAP_ANDROID(Digit9, 0x000A)
+
+CODE_MAP_WIN(Equal, 0x000D)
+CODE_MAP_MAC(Equal, kVK_ANSI_Equal)
+CODE_MAP_X11(Equal, 0x0015)
+CODE_MAP_ANDROID(Equal, 0x000D)
+
+CODE_MAP_WIN(IntlBackslash, 0x0056)
+CODE_MAP_MAC(IntlBackslash, kVK_ISO_Section)
+CODE_MAP_X11(IntlBackslash, 0x005E)
+CODE_MAP_ANDROID(IntlBackslash, 0x0056)
+
+// Win: IntlHash's scan code is shared with "Backslash" key.
+// Mac: IntlHash's virtual key code is shared with "Backslash" key.
+// X11: IntlHash's scan code is shared with "Backslash" key.
+// Android: IntlHash's scan code is shared with "Backslash" key.
+
+CODE_MAP_WIN(IntlRo, 0x0073)
+CODE_MAP_MAC(IntlRo, kVK_JIS_Underscore)
+CODE_MAP_X11(IntlRo, 0x0061)
+CODE_MAP_ANDROID(IntlRo, 0x0059)
+
+CODE_MAP_WIN(IntlYen, 0x007D)
+CODE_MAP_MAC(IntlYen, kVK_JIS_Yen)
+CODE_MAP_X11(IntlYen, 0x0084)
+CODE_MAP_ANDROID(IntlYen, 0x007C)
+
+CODE_MAP_WIN(KeyA, 0x001E)
+CODE_MAP_MAC(KeyA, kVK_ANSI_A)
+CODE_MAP_X11(KeyA, 0x0026)
+CODE_MAP_ANDROID(KeyA, 0x001E)
+
+CODE_MAP_WIN(KeyB, 0x0030)
+CODE_MAP_MAC(KeyB, kVK_ANSI_B)
+CODE_MAP_X11(KeyB, 0x0038)
+CODE_MAP_ANDROID(KeyB, 0x0030)
+
+CODE_MAP_WIN(KeyC, 0x002E)
+CODE_MAP_MAC(KeyC, kVK_ANSI_C)
+CODE_MAP_X11(KeyC, 0x0036)
+CODE_MAP_ANDROID(KeyC, 0x002E)
+
+CODE_MAP_WIN(KeyD, 0x0020)
+CODE_MAP_MAC(KeyD, kVK_ANSI_D)
+CODE_MAP_X11(KeyD, 0x0028)
+CODE_MAP_ANDROID(KeyD, 0x0020)
+
+CODE_MAP_WIN(KeyE, 0x0012)
+CODE_MAP_MAC(KeyE, kVK_ANSI_E)
+CODE_MAP_X11(KeyE, 0x001A)
+CODE_MAP_ANDROID(KeyE, 0x0012)
+
+CODE_MAP_WIN(KeyF, 0x0021)
+CODE_MAP_MAC(KeyF, kVK_ANSI_F)
+CODE_MAP_X11(KeyF, 0x0029)
+CODE_MAP_ANDROID(KeyF, 0x0021)
+
+CODE_MAP_WIN(KeyG, 0x0022)
+CODE_MAP_MAC(KeyG, kVK_ANSI_G)
+CODE_MAP_X11(KeyG, 0x002A)
+CODE_MAP_ANDROID(KeyG, 0x0022)
+
+CODE_MAP_WIN(KeyH, 0x0023)
+CODE_MAP_MAC(KeyH, kVK_ANSI_H)
+CODE_MAP_X11(KeyH, 0x002B)
+CODE_MAP_ANDROID(KeyH, 0x0023)
+
+CODE_MAP_WIN(KeyI, 0x0017)
+CODE_MAP_MAC(KeyI, kVK_ANSI_I)
+CODE_MAP_X11(KeyI, 0x001F)
+CODE_MAP_ANDROID(KeyI, 0x0017)
+
+CODE_MAP_WIN(KeyJ, 0x0024)
+CODE_MAP_MAC(KeyJ, kVK_ANSI_J)
+CODE_MAP_X11(KeyJ, 0x002C)
+CODE_MAP_ANDROID(KeyJ, 0x0024)
+
+CODE_MAP_WIN(KeyK, 0x0025)
+CODE_MAP_MAC(KeyK, kVK_ANSI_K)
+CODE_MAP_X11(KeyK, 0x002D)
+CODE_MAP_ANDROID(KeyK, 0x0025)
+
+CODE_MAP_WIN(KeyL, 0x0026)
+CODE_MAP_MAC(KeyL, kVK_ANSI_L)
+CODE_MAP_X11(KeyL, 0x002E)
+CODE_MAP_ANDROID(KeyL, 0x0026)
+
+CODE_MAP_WIN(KeyM, 0x0032)
+CODE_MAP_MAC(KeyM, kVK_ANSI_M)
+CODE_MAP_X11(KeyM, 0x003A)
+CODE_MAP_ANDROID(KeyM, 0x0032)
+
+CODE_MAP_WIN(KeyN, 0x0031)
+CODE_MAP_MAC(KeyN, kVK_ANSI_N)
+CODE_MAP_X11(KeyN, 0x0039)
+CODE_MAP_ANDROID(KeyN, 0x0031)
+
+CODE_MAP_WIN(KeyO, 0x0018)
+CODE_MAP_MAC(KeyO, kVK_ANSI_O)
+CODE_MAP_X11(KeyO, 0x0020)
+CODE_MAP_ANDROID(KeyO, 0x0018)
+
+CODE_MAP_WIN(KeyP, 0x0019)
+CODE_MAP_MAC(KeyP, kVK_ANSI_P)
+CODE_MAP_X11(KeyP, 0x0021)
+CODE_MAP_ANDROID(KeyP, 0x0019)
+
+CODE_MAP_WIN(KeyQ, 0x0010)
+CODE_MAP_MAC(KeyQ, kVK_ANSI_Q)
+CODE_MAP_X11(KeyQ, 0x0018)
+CODE_MAP_ANDROID(KeyQ, 0x0010)
+
+CODE_MAP_WIN(KeyR, 0x0013)
+CODE_MAP_MAC(KeyR, kVK_ANSI_R)
+CODE_MAP_X11(KeyR, 0x001B)
+CODE_MAP_ANDROID(KeyR, 0x0013)
+
+CODE_MAP_WIN(KeyS, 0x001F)
+CODE_MAP_MAC(KeyS, kVK_ANSI_S)
+CODE_MAP_X11(KeyS, 0x0027)
+CODE_MAP_ANDROID(KeyS, 0x001F)
+
+CODE_MAP_WIN(KeyT, 0x0014)
+CODE_MAP_MAC(KeyT, kVK_ANSI_T)
+CODE_MAP_X11(KeyT, 0x001C)
+CODE_MAP_ANDROID(KeyT, 0x0014)
+
+CODE_MAP_WIN(KeyU, 0x0016)
+CODE_MAP_MAC(KeyU, kVK_ANSI_U)
+CODE_MAP_X11(KeyU, 0x001E)
+CODE_MAP_ANDROID(KeyU, 0x0016)
+
+CODE_MAP_WIN(KeyV, 0x002F)
+CODE_MAP_MAC(KeyV, kVK_ANSI_V)
+CODE_MAP_X11(KeyV, 0x0037)
+CODE_MAP_ANDROID(KeyV, 0x002F)
+
+CODE_MAP_WIN(KeyW, 0x0011)
+CODE_MAP_MAC(KeyW, kVK_ANSI_W)
+CODE_MAP_X11(KeyW, 0x0019)
+CODE_MAP_ANDROID(KeyW, 0x0011)
+
+CODE_MAP_WIN(KeyX, 0x002D)
+CODE_MAP_MAC(KeyX, kVK_ANSI_X)
+CODE_MAP_X11(KeyX, 0x0035)
+CODE_MAP_ANDROID(KeyX, 0x002D)
+
+CODE_MAP_WIN(KeyY, 0x0015)
+CODE_MAP_MAC(KeyY, kVK_ANSI_Y)
+CODE_MAP_X11(KeyY, 0x001D)
+CODE_MAP_ANDROID(KeyY, 0x0015)
+
+CODE_MAP_WIN(KeyZ, 0x002C)
+CODE_MAP_MAC(KeyZ, kVK_ANSI_Z)
+CODE_MAP_X11(KeyZ, 0x0034)
+CODE_MAP_ANDROID(KeyZ, 0x002C)
+
+CODE_MAP_WIN(Minus, 0x000C)
+CODE_MAP_MAC(Minus, kVK_ANSI_Minus)
+CODE_MAP_X11(Minus, 0x0014)
+CODE_MAP_ANDROID(Minus, 0x000C)
+
+CODE_MAP_WIN(Period, 0x0034)
+CODE_MAP_MAC(Period, kVK_ANSI_Period)
+CODE_MAP_X11(Period, 0x003C)
+CODE_MAP_ANDROID(Period, 0x0034)
+
+CODE_MAP_WIN(Quote, 0x0028)
+CODE_MAP_MAC(Quote, kVK_ANSI_Quote)
+CODE_MAP_X11(Quote, 0x0030)
+CODE_MAP_ANDROID(Quote, 0x0028)
+
+CODE_MAP_WIN(Semicolon, 0x0027)
+CODE_MAP_MAC(Semicolon, kVK_ANSI_Semicolon)
+CODE_MAP_X11(Semicolon, 0x002F)
+CODE_MAP_ANDROID(Semicolon, 0x0027)
+
+CODE_MAP_WIN(Slash, 0x0035)
+CODE_MAP_MAC(Slash, kVK_ANSI_Slash)
+CODE_MAP_X11(Slash, 0x003D)
+CODE_MAP_ANDROID(Slash, 0x0035)
+
+// Functional keys
+CODE_MAP_WIN(AltLeft, 0x0038)
+CODE_MAP_MAC(AltLeft, kVK_Option)
+CODE_MAP_X11(AltLeft, 0x0040)
+CODE_MAP_ANDROID(AltLeft, 0x0038)
+
+CODE_MAP_WIN(AltRight, 0xE038)
+CODE_MAP_MAC(AltRight, kVK_RightOption)
+CODE_MAP_X11(AltRight, 0x006C)
+CODE_MAP_ANDROID(AltRight, 0x0064)
+
+CODE_MAP_WIN(CapsLock, 0x003A)
+CODE_MAP_MAC(CapsLock, kVK_CapsLock)
+CODE_MAP_X11(CapsLock, 0x0042)
+CODE_MAP_ANDROID(CapsLock, 0x003A)
+
+CODE_MAP_WIN(ContextMenu, 0xE05D)
+CODE_MAP_MAC(ContextMenu, kVK_PC_ContextMenu)
+CODE_MAP_X11(ContextMenu, 0x0087)
+CODE_MAP_ANDROID(ContextMenu, 0x007F)
+
+CODE_MAP_WIN(ControlLeft, 0x001D)
+CODE_MAP_MAC(ControlLeft, kVK_Control)
+CODE_MAP_X11(ControlLeft, 0x0025)
+CODE_MAP_ANDROID(ControlLeft, 0x001D)
+
+CODE_MAP_WIN(ControlRight, 0xE01D)
+CODE_MAP_MAC(ControlRight, kVK_RightControl)
+CODE_MAP_X11(ControlRight, 0x0069)
+CODE_MAP_ANDROID(ControlRight, 0x0061)
+
+CODE_MAP_WIN(Enter, 0x001C)
+CODE_MAP_MAC(Enter, kVK_Return)
+CODE_MAP_X11(Enter, 0x0024)
+CODE_MAP_ANDROID(Enter, 0x001C)
+
+CODE_MAP_WIN(MetaLeft, 0xE05B)
+CODE_MAP_MAC(MetaLeft, kVK_Command)
+CODE_MAP_X11(MetaLeft, 0x0085)
+CODE_MAP_ANDROID(MetaLeft, 0x007D)
+
+CODE_MAP_WIN(MetaRight, 0xE05C)
+CODE_MAP_MAC(MetaRight, kVK_RightCommand)
+CODE_MAP_X11(MetaRight, 0x0086)
+CODE_MAP_ANDROID(MetaRight, 0x007E)
+
+CODE_MAP_WIN(ShiftLeft, 0x002A)
+CODE_MAP_MAC(ShiftLeft, kVK_Shift)
+CODE_MAP_X11(ShiftLeft, 0x0032)
+CODE_MAP_ANDROID(ShiftLeft, 0x002A)
+
+CODE_MAP_WIN(ShiftRight, 0x0036)
+CODE_MAP_MAC(ShiftRight, kVK_RightShift)
+CODE_MAP_X11(ShiftRight, 0x003E)
+CODE_MAP_ANDROID(ShiftRight, 0x0036)
+
+CODE_MAP_WIN(Space, 0x0039)
+CODE_MAP_MAC(Space, kVK_Space)
+CODE_MAP_X11(Space, 0x0041)
+CODE_MAP_ANDROID(Space, 0x0039)
+
+CODE_MAP_WIN(Tab, 0x000F)
+CODE_MAP_MAC(Tab, kVK_Tab)
+CODE_MAP_X11(Tab, 0x0017)
+CODE_MAP_ANDROID(Tab, 0x000F)
+
+// IME keys
+CODE_MAP_WIN(Convert, 0x0079)
+CODE_MAP_X11(Convert, 0x0064)
+CODE_MAP_ANDROID(Convert, 0x005C)
+
+CODE_MAP_WIN(Lang1, 0x0072)  // for non-Korean layout
+CODE_MAP_WIN(Lang1, 0xE0F2)  // for Korean layout
+CODE_MAP_MAC(Lang1, kVK_JIS_Kana)
+CODE_MAP_X11(Lang1, 0x0082)
+CODE_MAP_ANDROID(Lang1, 0x007A)
+
+CODE_MAP_WIN(Lang2, 0x0071)  // for non-Korean layout
+CODE_MAP_WIN(Lang2, 0xE0F1)  // for Korean layout
+CODE_MAP_MAC(Lang2, kVK_JIS_Eisu)
+CODE_MAP_X11(Lang2, 0x0083)
+CODE_MAP_ANDROID(Lang2, 0x007B)
+
+CODE_MAP_WIN(KanaMode, 0x0070)
+CODE_MAP_X11(KanaMode, 0x0065)
+CODE_MAP_ANDROID(KanaMode, 0x005D)
+
+CODE_MAP_WIN(NonConvert, 0x007B)
+CODE_MAP_X11(NonConvert, 0x0066)
+CODE_MAP_ANDROID(NonConvert, 0x005E)
+
+// Control pad section
+CODE_MAP_WIN(Delete, 0xE053)
+CODE_MAP_MAC(Delete, kVK_ForwardDelete)
+CODE_MAP_X11(Delete, 0x0077)
+CODE_MAP_ANDROID(Delete, 0x006F)
+
+CODE_MAP_WIN(End, 0xE04F)
+CODE_MAP_MAC(End, kVK_End)
+CODE_MAP_X11(End, 0x0073)
+CODE_MAP_ANDROID(End, 0x006B)
+
+CODE_MAP_MAC(Help, kVK_Help)    // Insert key on PC keyboard
+CODE_MAP_X11(Help, 0x0092)      // Help key on Sun keyboard
+CODE_MAP_ANDROID(Help, 0x008A)  // Help key on Sun keyboard
+
+CODE_MAP_WIN(Home, 0xE047)
+CODE_MAP_MAC(Home, kVK_Home)
+CODE_MAP_X11(Home, 0x006E)
+CODE_MAP_ANDROID(Home, 0x0066)
+
+CODE_MAP_WIN(Insert, 0xE052)
+CODE_MAP_X11(Insert, 0x0076)
+CODE_MAP_ANDROID(Insert, 0x006E)
+
+CODE_MAP_WIN(PageDown, 0xE051)
+CODE_MAP_MAC(PageDown, kVK_PageDown)
+CODE_MAP_X11(PageDown, 0x0075)
+CODE_MAP_ANDROID(PageDown, 0x006D)
+
+CODE_MAP_WIN(PageUp, 0xE049)
+CODE_MAP_MAC(PageUp, kVK_PageUp)
+CODE_MAP_X11(PageUp, 0x0070)
+CODE_MAP_ANDROID(PageUp, 0x0068)
+
+// Arrow pad section
+CODE_MAP_WIN(ArrowDown, 0xE050)
+CODE_MAP_MAC(ArrowDown, kVK_DownArrow)
+CODE_MAP_X11(ArrowDown, 0x0074)
+CODE_MAP_ANDROID(ArrowDown, 0x006C)
+
+CODE_MAP_WIN(ArrowLeft, 0xE04B)
+CODE_MAP_MAC(ArrowLeft, kVK_LeftArrow)
+CODE_MAP_X11(ArrowLeft, 0x0071)
+CODE_MAP_ANDROID(ArrowLeft, 0x0069)
+
+CODE_MAP_WIN(ArrowRight, 0xE04D)
+CODE_MAP_MAC(ArrowRight, kVK_RightArrow)
+CODE_MAP_X11(ArrowRight, 0x0072)
+CODE_MAP_ANDROID(ArrowRight, 0x006A)
+
+CODE_MAP_WIN(ArrowUp, 0xE048)
+CODE_MAP_MAC(ArrowUp, kVK_UpArrow)
+CODE_MAP_X11(ArrowUp, 0x006F)
+CODE_MAP_ANDROID(ArrowUp, 0x0067)
+
+// Numpad section
+CODE_MAP_WIN(NumLock, 0xE045)  // MSDN says 0x0045, though...
+CODE_MAP_MAC(NumLock, kVK_ANSI_KeypadClear)
+CODE_MAP_X11(NumLock, 0x004D)
+CODE_MAP_ANDROID(NumLock, 0x0045)
+
+CODE_MAP_WIN(Numpad0, 0x0052)
+CODE_MAP_MAC(Numpad0, kVK_ANSI_Keypad0)
+CODE_MAP_X11(Numpad0, 0x005A)
+CODE_MAP_ANDROID(Numpad0, 0x0052)
+
+CODE_MAP_WIN(Numpad1, 0x004F)
+CODE_MAP_MAC(Numpad1, kVK_ANSI_Keypad1)
+CODE_MAP_X11(Numpad1, 0x0057)
+CODE_MAP_ANDROID(Numpad1, 0x004F)
+
+CODE_MAP_WIN(Numpad2, 0x0050)
+CODE_MAP_MAC(Numpad2, kVK_ANSI_Keypad2)
+CODE_MAP_X11(Numpad2, 0x0058)
+CODE_MAP_ANDROID(Numpad2, 0x0050)
+
+CODE_MAP_WIN(Numpad3, 0x0051)
+CODE_MAP_MAC(Numpad3, kVK_ANSI_Keypad3)
+CODE_MAP_X11(Numpad3, 0x0059)
+CODE_MAP_ANDROID(Numpad3, 0x0051)
+
+CODE_MAP_WIN(Numpad4, 0x004B)
+CODE_MAP_MAC(Numpad4, kVK_ANSI_Keypad4)
+CODE_MAP_X11(Numpad4, 0x0053)
+CODE_MAP_ANDROID(Numpad4, 0x004B)
+
+CODE_MAP_WIN(Numpad5, 0x004C)
+CODE_MAP_MAC(Numpad5, kVK_ANSI_Keypad5)
+CODE_MAP_X11(Numpad5, 0x0054)
+CODE_MAP_ANDROID(Numpad5, 0x004C)
+
+CODE_MAP_WIN(Numpad6, 0x004D)
+CODE_MAP_MAC(Numpad6, kVK_ANSI_Keypad6)
+CODE_MAP_X11(Numpad6, 0x0055)
+CODE_MAP_ANDROID(Numpad6, 0x004D)
+
+CODE_MAP_WIN(Numpad7, 0x0047)
+CODE_MAP_MAC(Numpad7, kVK_ANSI_Keypad7)
+CODE_MAP_X11(Numpad7, 0x004F)
+CODE_MAP_ANDROID(Numpad7, 0x0047)
+
+CODE_MAP_WIN(Numpad8, 0x0048)
+CODE_MAP_MAC(Numpad8, kVK_ANSI_Keypad8)
+CODE_MAP_X11(Numpad8, 0x0050)
+CODE_MAP_ANDROID(Numpad8, 0x0048)
+
+CODE_MAP_WIN(Numpad9, 0x0049)
+CODE_MAP_MAC(Numpad9, kVK_ANSI_Keypad9)
+CODE_MAP_X11(Numpad9, 0x0051)
+CODE_MAP_ANDROID(Numpad9, 0x0049)
+
+CODE_MAP_WIN(NumpadAdd, 0x004E)
+CODE_MAP_MAC(NumpadAdd, kVK_ANSI_KeypadPlus)
+CODE_MAP_X11(NumpadAdd, 0x0056)
+CODE_MAP_ANDROID(NumpadAdd, 0x004E)
+
+CODE_MAP_WIN(NumpadComma, 0x007E)
+CODE_MAP_MAC(NumpadComma, kVK_JIS_KeypadComma)
+CODE_MAP_X11(NumpadComma, 0x0081)
+CODE_MAP_ANDROID(NumpadComma, 0x0079)
+
+CODE_MAP_WIN(NumpadDecimal, 0x0053)
+CODE_MAP_MAC(NumpadDecimal, kVK_ANSI_KeypadDecimal)
+CODE_MAP_X11(NumpadDecimal, 0x005B)
+CODE_MAP_ANDROID(NumpadDecimal, 0x0053)
+
+CODE_MAP_WIN(NumpadDivide, 0xE035)
+CODE_MAP_MAC(NumpadDivide, kVK_ANSI_KeypadDivide)
+CODE_MAP_X11(NumpadDivide, 0x006A)
+CODE_MAP_ANDROID(NumpadDivide, 0x0062)
+
+CODE_MAP_WIN(NumpadEnter, 0xE01C)
+CODE_MAP_MAC(NumpadEnter, kVK_ANSI_KeypadEnter)
+CODE_MAP_MAC(NumpadEnter, kVK_Powerbook_KeypadEnter)
+CODE_MAP_X11(NumpadEnter, 0x0068)
+CODE_MAP_ANDROID(NumpadEnter, 0x0060)
+
+CODE_MAP_WIN(NumpadEqual, 0x0059)
+CODE_MAP_MAC(NumpadEqual, kVK_ANSI_KeypadEquals)
+CODE_MAP_X11(NumpadEqual, 0x007D)
+CODE_MAP_ANDROID(NumpadEqual, 0x0075)
+
+CODE_MAP_WIN(NumpadMultiply, 0x0037)
+CODE_MAP_MAC(NumpadMultiply, kVK_ANSI_KeypadMultiply)
+CODE_MAP_X11(NumpadMultiply, 0x003F)
+CODE_MAP_ANDROID(NumpadMultiply, 0x0037)
+
+CODE_MAP_WIN(NumpadSubtract, 0x004A)
+CODE_MAP_MAC(NumpadSubtract, kVK_ANSI_KeypadMinus)
+CODE_MAP_X11(NumpadSubtract, 0x0052)
+CODE_MAP_ANDROID(NumpadSubtract, 0x004A)
+
+// Function section
+CODE_MAP_WIN(Escape, 0x0001)
+CODE_MAP_MAC(Escape, kVK_Escape)
+CODE_MAP_X11(Escape, 0x0009)
+CODE_MAP_ANDROID(Escape, 0x0001)
+
+CODE_MAP_WIN(F1, 0x003B)
+CODE_MAP_MAC(F1, kVK_F1)
+CODE_MAP_X11(F1, 0x0043)
+CODE_MAP_ANDROID(F1, 0x003B)
+
+CODE_MAP_WIN(F2, 0x003C)
+CODE_MAP_MAC(F2, kVK_F2)
+CODE_MAP_X11(F2, 0x0044)
+CODE_MAP_ANDROID(F2, 0x003C)
+
+CODE_MAP_WIN(F3, 0x003D)
+CODE_MAP_MAC(F3, kVK_F3)
+CODE_MAP_X11(F3, 0x0045)
+CODE_MAP_ANDROID(F3, 0x003D)
+
+CODE_MAP_WIN(F4, 0x003E)
+CODE_MAP_MAC(F4, kVK_F4)
+CODE_MAP_X11(F4, 0x0046)
+CODE_MAP_ANDROID(F4, 0x003E)
+
+CODE_MAP_WIN(F5, 0x003F)
+CODE_MAP_MAC(F5, kVK_F5)
+CODE_MAP_X11(F5, 0x0047)
+CODE_MAP_ANDROID(F5, 0x003F)
+
+CODE_MAP_WIN(F6, 0x0040)
+CODE_MAP_MAC(F6, kVK_F6)
+CODE_MAP_X11(F6, 0x0048)
+CODE_MAP_ANDROID(F6, 0x0040)
+
+CODE_MAP_WIN(F7, 0x0041)
+CODE_MAP_MAC(F7, kVK_F7)
+CODE_MAP_X11(F7, 0x0049)
+CODE_MAP_ANDROID(F7, 0x0041)
+
+CODE_MAP_WIN(F8, 0x0042)
+CODE_MAP_MAC(F8, kVK_F8)
+CODE_MAP_X11(F8, 0x004A)
+CODE_MAP_ANDROID(F8, 0x0042)
+
+CODE_MAP_WIN(F9, 0x0043)
+CODE_MAP_MAC(F9, kVK_F9)
+CODE_MAP_X11(F9, 0x004B)
+CODE_MAP_ANDROID(F9, 0x0043)
+
+CODE_MAP_WIN(F10, 0x0044)
+CODE_MAP_MAC(F10, kVK_F10)
+CODE_MAP_X11(F10, 0x004C)
+CODE_MAP_ANDROID(F10, 0x0044)
+
+CODE_MAP_WIN(F11, 0x0057)
+CODE_MAP_MAC(F11, kVK_F11)
+CODE_MAP_X11(F11, 0x005F)
+CODE_MAP_ANDROID(F11, 0x0057)
+
+CODE_MAP_WIN(F12, 0x0058)
+CODE_MAP_MAC(F12, kVK_F12)
+CODE_MAP_X11(F12, 0x0060)
+CODE_MAP_ANDROID(F12, 0x0058)
+
+CODE_MAP_WIN(F13, 0x0064)
+CODE_MAP_MAC(F13, kVK_F13)  // PrintScreen on PC keyboard
+CODE_MAP_X11(F13, 0x00BF)
+CODE_MAP_ANDROID(F13, 0x00B7)
+
+CODE_MAP_WIN(F14, 0x0065)
+CODE_MAP_MAC(F14, kVK_F14)  // ScrollLock on PC keyboard
+CODE_MAP_X11(F14, 0x00C0)
+CODE_MAP_ANDROID(F14, 0x00B8)
+
+CODE_MAP_WIN(F15, 0x0066)
+CODE_MAP_MAC(F15, kVK_F15)  // Pause on PC keyboard
+CODE_MAP_X11(F15, 0x00C1)
+CODE_MAP_ANDROID(F15, 0x00B9)
+
+CODE_MAP_WIN(F16, 0x0067)
+CODE_MAP_MAC(F16, kVK_F16)
+CODE_MAP_X11(F16, 0x00C2)
+CODE_MAP_ANDROID(F16, 0x00BA)
+
+CODE_MAP_WIN(F17, 0x0068)
+CODE_MAP_MAC(F17, kVK_F17)
+CODE_MAP_X11(F17, 0x00C3)
+CODE_MAP_ANDROID(F17, 0x00BB)
+
+CODE_MAP_WIN(F18, 0x0069)
+CODE_MAP_MAC(F18, kVK_F18)
+CODE_MAP_X11(F18, 0x00C4)
+CODE_MAP_ANDROID(F18, 0x00BC)
+
+CODE_MAP_WIN(F19, 0x006A)
+CODE_MAP_MAC(F19, kVK_F19)
+CODE_MAP_X11(F19, 0x00C5)
+CODE_MAP_ANDROID(F19, 0x00BD)
+
+CODE_MAP_WIN(F20, 0x006B)
+CODE_MAP_MAC(F20, kVK_F20)
+CODE_MAP_X11(F20, 0x00C6)
+CODE_MAP_ANDROID(F20, 0x00BE)
+
+CODE_MAP_WIN(F21, 0x006C)
+CODE_MAP_X11(F21, 0x00C7)
+CODE_MAP_ANDROID(F21, 0x00BF)
+
+CODE_MAP_WIN(F22, 0x006D)
+CODE_MAP_X11(F22, 0x00C8)
+CODE_MAP_ANDROID(F22, 0x00C0)
+
+CODE_MAP_WIN(F23, 0x006E)
+CODE_MAP_X11(F23, 0x00C9)
+CODE_MAP_ANDROID(F23, 0x00C1)
+
+CODE_MAP_WIN(F24, 0x0076)
+CODE_MAP_X11(F24, 0x00CA)
+CODE_MAP_ANDROID(F24, 0x00C2)
+
+CODE_MAP_MAC(Fn, kVK_Function)  // not available?
+CODE_MAP_ANDROID(Fn, 0x01D0)
+
+CODE_MAP_WIN(PrintScreen, 0xE037)
+CODE_MAP_WIN(PrintScreen, 0x0054)  // Alt + PrintScreen
+CODE_MAP_X11(PrintScreen, 0x006B)
+CODE_MAP_ANDROID(PrintScreen, 0x0063)
+
+CODE_MAP_WIN(ScrollLock, 0x0046)
+CODE_MAP_X11(ScrollLock, 0x004E)
+CODE_MAP_ANDROID(ScrollLock, 0x0046)
+
+CODE_MAP_WIN(Pause, 0x0045)
+CODE_MAP_WIN(Pause, 0xE046)  // Ctrl + Pause
+CODE_MAP_X11(Pause, 0x007F)
+CODE_MAP_ANDROID(Pause, 0x0077)
+
+// Media keys
+CODE_MAP_WIN(BrowserBack, 0xE06A)
+CODE_MAP_X11(BrowserBack, 0x00A6)
+CODE_MAP_ANDROID(BrowserBack, 0x009E)
+
+CODE_MAP_WIN(BrowserFavorites, 0xE066)
+CODE_MAP_X11(BrowserFavorites, 0x00A4)
+CODE_MAP_ANDROID(BrowserFavorites, 0x009C)
+
+CODE_MAP_WIN(BrowserForward, 0xE069)
+CODE_MAP_X11(BrowserForward, 0x00A7)
+CODE_MAP_ANDROID(BrowserForward, 0x009F)
+
+CODE_MAP_WIN(BrowserHome, 0xE032)
+CODE_MAP_X11(BrowserHome, 0x00B4)
+// CODE_MAP_ANDROID(BrowserHome) // not available? works as Home key.
+
+CODE_MAP_WIN(BrowserRefresh, 0xE067)
+CODE_MAP_X11(BrowserRefresh, 0x00B5)
+CODE_MAP_ANDROID(BrowserRefresh, 0x00AD)
+
+CODE_MAP_WIN(BrowserSearch, 0xE065)
+CODE_MAP_X11(BrowserSearch, 0x00E1)
+CODE_MAP_ANDROID(BrowserSearch, 0x00D9)
+
+CODE_MAP_WIN(BrowserStop, 0xE068)
+CODE_MAP_X11(BrowserStop, 0x0088)
+CODE_MAP_ANDROID(BrowserStop, 0x0080)
+
+// CODE_MAP_WIN(Eject) // not available?
+// CODE_MAP_MAC(Eject) // not available?
+CODE_MAP_X11(Eject, 0x00A9)
+CODE_MAP_ANDROID(Eject, 0x00A1)
+
+CODE_MAP_WIN(LaunchApp1, 0xE06B)
+CODE_MAP_X11(LaunchApp1, 0x0098)
+CODE_MAP_ANDROID(LaunchApp1, 0x0090)
+
+CODE_MAP_WIN(LaunchApp2, 0xE021)
+CODE_MAP_X11(LaunchApp2, 0x0094)
+// CODE_MAP_ANDROID(LaunchApp2) // not available?
+
+CODE_MAP_WIN(LaunchMail, 0xE06C)
+CODE_MAP_X11(LaunchMail, 0x00A3)
+// CODE_MAP_ANDROID(LaunchMail) // not available?
+
+CODE_MAP_WIN(MediaPlayPause, 0xE022)
+CODE_MAP_X11(MediaPlayPause, 0x00AC)
+CODE_MAP_ANDROID(MediaPlayPause, 0x00A4)
+
+CODE_MAP_WIN(MediaSelect, 0xE06D)
+CODE_MAP_X11(MediaSelect, 0x00B3)
+// CODE_MAP_ANDROID(MediaSelect) // not available?
+
+CODE_MAP_WIN(MediaStop, 0xE024)
+CODE_MAP_X11(MediaStop, 0x00AE)
+CODE_MAP_ANDROID(MediaStop, 0x00A6)
+
+CODE_MAP_WIN(MediaTrackNext, 0xE019)
+CODE_MAP_X11(MediaTrackNext, 0x00AB)
+CODE_MAP_ANDROID(MediaTrackNext, 0x00A3)
+
+CODE_MAP_WIN(MediaTrackPrevious, 0xE010)
+CODE_MAP_X11(MediaTrackPrevious, 0x00AD)
+CODE_MAP_ANDROID(MediaTrackPrevious, 0x00A5)
+
+CODE_MAP_WIN(Power, 0xE05E)
+CODE_MAP_MAC(Power, 0x007F)  // On 10.7 and 10.8 only
+// CODE_MAP_X11(Power) // not available?
+CODE_MAP_ANDROID(Power, 0x0074)
+
+// CODE_MAP_WIN(Sleep) // not available?
+// CODE_MAP_X11(Sleep) // not available?
+CODE_MAP_ANDROID(Sleep, 0x008E)
+
+CODE_MAP_WIN(VolumeDown, 0xE02E)
+CODE_MAP_MAC(VolumeDown, kVK_VolumeDown)  // not available?
+CODE_MAP_X11(VolumeDown, 0x007A)
+CODE_MAP_ANDROID(VolumeDown, 0x0072)
+
+CODE_MAP_WIN(VolumeMute, 0xE020)
+CODE_MAP_MAC(VolumeMute, kVK_Mute)  // not available?
+CODE_MAP_X11(VolumeMute, 0x0079)
+CODE_MAP_ANDROID(VolumeMute, 0x0071)
+
+CODE_MAP_WIN(VolumeUp, 0xE030)
+CODE_MAP_MAC(VolumeUp, kVK_VolumeUp)  // not available?
+CODE_MAP_X11(VolumeUp, 0x007B)
+CODE_MAP_ANDROID(VolumeUp, 0x0073)  // side of body, not on keyboard
+
+// CODE_MAP_WIN(WakeUp) // not available?
+CODE_MAP_X11(WakeUp, 0x0097)
+CODE_MAP_ANDROID(WakeUp, 0x008F)
+
+// Legacy editing keys
+CODE_MAP_X11(Again, 0x0089)      // Again key on Sun keyboard
+CODE_MAP_ANDROID(Again, 0x0081)  // Again key on Sun keyboard
+
+CODE_MAP_X11(Copy, 0x008D)      // Copy key on Sun keyboard
+CODE_MAP_ANDROID(Copy, 0x0085)  // Copy key on Sun keyboard
+
+CODE_MAP_X11(Cut, 0x0091)      // Cut key on Sun keyboard
+CODE_MAP_ANDROID(Cut, 0x0089)  // Cut key on Sun keyboard
+
+CODE_MAP_X11(Find, 0x0090)      // Find key on Sun keyboard
+CODE_MAP_ANDROID(Find, 0x0088)  // Find key on Sun keyboard
+
+CODE_MAP_X11(Open, 0x008E)      // Open key on Sun keyboard
+CODE_MAP_ANDROID(Open, 0x0086)  // Open key on Sun keyboard
+
+CODE_MAP_X11(Paste, 0x008F)      // Paste key on Sun keyboard
+CODE_MAP_ANDROID(Paste, 0x0087)  // Paste key on Sun keyboard
+
+CODE_MAP_X11(Props, 0x008A)      // Props key on Sun keyboard
+CODE_MAP_ANDROID(Props, 0x0082)  // Props key on Sun keyboard
+
+CODE_MAP_X11(Select, 0x008C)      // Front key on Sun keyboard
+CODE_MAP_ANDROID(Select, 0x0084)  // Front key on Sun keyboard
+
+CODE_MAP_X11(Undo, 0x008B)      // Undo key on Sun keyboard
+CODE_MAP_ANDROID(Undo, 0x0083)  // Undo key on Sun keyboard
+
+#undef CODE_MAP_WIN
+#undef CODE_MAP_MAC
+#undef CODE_MAP_X11
+#undef CODE_MAP_ANDROID
diff --git a/widget/NativeKeyToDOMKeyName.h b/widget/NativeKeyToDOMKeyName.h
new file mode 100644
index 0000000000..af079bef5b
--- /dev/null
+++ b/widget/NativeKeyToDOMKeyName.h
@@ -0,0 +1,1286 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This header file defines simple key mapping between native keycode value and
+ * DOM key name index.
+ * You must define NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX macro before include
+ * this.
+ *
+ * It must have two arguments, (aNativeKey, aKeyNameIndex).
+ * aNativeKey is a native keycode value.
+ * aKeyNameIndex is the widget::KeyNameIndex value.
+ */
+
+// Windows
+#define KEY_MAP_WIN(aCPPKeyName, aNativeKey)
+#define KEY_MAP_WIN_JPN(aCPPKeyName, aNativeKey)
+#define KEY_MAP_WIN_KOR(aCPPKeyName, aNativeKey)
+#define KEY_MAP_WIN_OTH(aCPPKeyName, aNativeKey)
+#define KEY_MAP_WIN_CMD(aCPPKeyName, aAppCommand)
+// Mac OS X
+#define KEY_MAP_COCOA(aCPPKeyName, aNativeKey)
+// GTK
+#define KEY_MAP_GTK(aCPPKeyName, aNativeKey)
+// Only for Android
+#define KEY_MAP_ANDROID(aCPPKeyName, aNativeKey)
+
+#if defined(XP_WIN)
+#  if defined(NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX)
+// KEY_MAP_WIN() defines the mapping not depending on keyboard layout.
+#    undef KEY_MAP_WIN
+#    define KEY_MAP_WIN(aCPPKeyName, aNativeKey)      \
+      NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, \
+                                          KEY_NAME_INDEX_##aCPPKeyName)
+#  elif defined(NS_JAPANESE_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX)
+// KEY_MAP_WIN_JPN() defines the mapping which is valid only with Japanese
+// keyboard layout.
+#    undef KEY_MAP_WIN_JPN
+#    define KEY_MAP_WIN_JPN(aCPPKeyName, aNativeKey) \
+      NS_JAPANESE_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(  \
+          aNativeKey, KEY_NAME_INDEX_##aCPPKeyName)
+#  elif defined(NS_KOREAN_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX)
+// KEY_MAP_WIN_KOR() defines the mapping which is valid only with Korean
+// keyboard layout.
+#    undef KEY_MAP_WIN_KOR
+#    define KEY_MAP_WIN_KOR(aCPPKeyName, aNativeKey)         \
+      NS_KOREAN_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, \
+                                                 KEY_NAME_INDEX_##aCPPKeyName)
+#  elif defined(NS_OTHER_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX)
+// KEY_MAP_WIN_OTH() defines the mapping which is valid with neither
+// Japanese keyboard layout nor Korean keyboard layout.
+#    undef KEY_MAP_WIN_OTH
+#    define KEY_MAP_WIN_OTH(aCPPKeyName, aNativeKey)        \
+      NS_OTHER_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, \
+                                                KEY_NAME_INDEX_##aCPPKeyName)
+#  elif defined(NS_APPCOMMAND_TO_DOM_KEY_NAME_INDEX)
+// KEY_MAP_WIN_CMD() defines the mapping from APPCOMMAND_* of WM_APPCOMMAND.
+#    undef KEY_MAP_WIN_CMD
+#    define KEY_MAP_WIN_CMD(aCPPKeyName, aAppCommand)  \
+      NS_APPCOMMAND_TO_DOM_KEY_NAME_INDEX(aAppCommand, \
+                                          KEY_NAME_INDEX_##aCPPKeyName)
+#  else
+#    error Any NS_*_TO_DOM_KEY_NAME_INDEX() is not defined.
+#  endif  // #if defined(NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX) ...
+#elif defined(XP_MACOSX)
+#  undef KEY_MAP_COCOA
+#  define KEY_MAP_COCOA(aCPPKeyName, aNativeKey)    \
+    NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, \
+                                        KEY_NAME_INDEX_##aCPPKeyName)
+#elif defined(MOZ_WIDGET_GTK)
+#  undef KEY_MAP_GTK
+#  define KEY_MAP_GTK(aCPPKeyName, aNativeKey)      \
+    NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, \
+                                        KEY_NAME_INDEX_##aCPPKeyName)
+#elif defined(ANDROID)
+#  undef KEY_MAP_ANDROID
+#  define KEY_MAP_ANDROID(aCPPKeyName, aNativeKey)  \
+    NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, \
+                                        KEY_NAME_INDEX_##aCPPKeyName)
+#endif
+
+/******************************************************************************
+ * Modifier Keys
+ ******************************************************************************/
+// Alt
+KEY_MAP_WIN(Alt, VK_MENU)
+KEY_MAP_WIN(Alt, VK_LMENU)
+KEY_MAP_WIN(Alt, VK_RMENU)  // This is ignored if active keyboard layout
+                            // has AltGr.  In such case, AltGraph is mapped.
+KEY_MAP_COCOA(Alt, kVK_Option)
+KEY_MAP_COCOA(Alt, kVK_RightOption)
+KEY_MAP_GTK(Alt, GDK_Alt_L)
+KEY_MAP_GTK(Alt, GDK_Alt_R)
+KEY_MAP_GTK(Alt, GDK_Meta_L)
+KEY_MAP_GTK(Alt, GDK_Meta_R)
+KEY_MAP_ANDROID(Alt, AKEYCODE_ALT_LEFT)
+KEY_MAP_ANDROID(Alt, AKEYCODE_ALT_RIGHT)
+
+// AltGraph
+KEY_MAP_GTK     (AltGraph, GDK_Mode_switch /* same as GDK_kana_switch,
+                                              GDK_ISO_Group_Shift and
+                                              GDK_script_switch */)
+// Let's treat both Level 3 shift and Level 5 shift as AltGr.
+// And also, let's treat Latch key and Lock key as AltGr key too like
+// GDK_Shift_Lock.
+KEY_MAP_GTK(AltGraph, GDK_ISO_Level3_Shift)
+KEY_MAP_GTK(AltGraph, GDK_ISO_Level3_Latch)
+KEY_MAP_GTK(AltGraph, GDK_ISO_Level3_Lock)
+KEY_MAP_GTK(AltGraph, GDK_ISO_Level5_Shift)
+KEY_MAP_GTK(AltGraph, GDK_ISO_Level5_Latch)
+KEY_MAP_GTK(AltGraph, GDK_ISO_Level5_Lock)
+
+// CapsLock
+KEY_MAP_WIN(CapsLock, VK_CAPITAL)
+KEY_MAP_COCOA(CapsLock, kVK_CapsLock)
+KEY_MAP_GTK(CapsLock, GDK_Caps_Lock)
+KEY_MAP_ANDROID(CapsLock, AKEYCODE_CAPS_LOCK)
+
+// Control
+KEY_MAP_WIN(Control, VK_CONTROL)
+KEY_MAP_WIN(Control, VK_LCONTROL)
+KEY_MAP_WIN(Control, VK_RCONTROL)
+KEY_MAP_COCOA(Control, kVK_Control)
+KEY_MAP_COCOA(Control, kVK_RightControl)
+KEY_MAP_GTK(Control, GDK_Control_L)
+KEY_MAP_GTK(Control, GDK_Control_R)
+KEY_MAP_ANDROID(Control, AKEYCODE_CTRL_LEFT)
+KEY_MAP_ANDROID(Control, AKEYCODE_CTRL_RIGHT)
+
+// Fn
+KEY_MAP_COCOA(Fn, kVK_Function)
+KEY_MAP_ANDROID(Fn, AKEYCODE_FUNCTION)
+
+// Meta
+KEY_MAP_WIN(Meta, VK_LWIN)
+KEY_MAP_WIN(Meta, VK_RWIN)
+KEY_MAP_COCOA(Meta, kVK_Command)
+KEY_MAP_COCOA(Meta, kVK_RightCommand)
+KEY_MAP_GTK(Meta, GDK_Super_L)
+KEY_MAP_GTK(Meta, GDK_Super_R)
+KEY_MAP_GTK(Meta, GDK_Hyper_L)
+KEY_MAP_GTK(Meta, GDK_Hyper_R)
+KEY_MAP_ANDROID(Meta, AKEYCODE_META_LEFT)
+KEY_MAP_ANDROID(Meta, AKEYCODE_META_RIGHT)
+
+// NumLock
+KEY_MAP_WIN(NumLock, VK_NUMLOCK)
+KEY_MAP_GTK(NumLock, GDK_Num_Lock)
+KEY_MAP_ANDROID(NumLock, AKEYCODE_NUM_LOCK)
+
+// ScrollLock
+KEY_MAP_WIN(ScrollLock, VK_SCROLL)
+KEY_MAP_GTK(ScrollLock, GDK_Scroll_Lock)
+KEY_MAP_ANDROID(ScrollLock, AKEYCODE_SCROLL_LOCK)
+
+// Shift
+KEY_MAP_WIN(Shift, VK_SHIFT)
+KEY_MAP_WIN(Shift, VK_LSHIFT)
+KEY_MAP_WIN(Shift, VK_RSHIFT)
+KEY_MAP_COCOA(Shift, kVK_Shift)
+KEY_MAP_COCOA(Shift, kVK_RightShift)
+KEY_MAP_GTK(Shift, GDK_Shift_L)
+KEY_MAP_GTK(Shift, GDK_Shift_R)
+KEY_MAP_GTK(Shift, GDK_Shift_Lock)  // Let's treat as Shift key (bug 769159)
+KEY_MAP_ANDROID(Shift, AKEYCODE_SHIFT_LEFT)
+KEY_MAP_ANDROID(Shift, AKEYCODE_SHIFT_RIGHT)
+
+// Symbol
+KEY_MAP_ANDROID(Symbol, AKEYCODE_SYM)
+
+/******************************************************************************
+ * Whitespace Keys
+ ******************************************************************************/
+// Enter
+KEY_MAP_WIN(Enter, VK_RETURN)
+KEY_MAP_COCOA(Enter, kVK_Return)
+KEY_MAP_COCOA(Enter, kVK_ANSI_KeypadEnter)
+KEY_MAP_COCOA(Enter, kVK_Powerbook_KeypadEnter)
+KEY_MAP_GTK(Enter, GDK_Return)
+KEY_MAP_GTK(Enter, GDK_KP_Enter)
+KEY_MAP_GTK(Enter, GDK_ISO_Enter)
+KEY_MAP_GTK(Enter, GDK_3270_Enter)
+KEY_MAP_ANDROID(Enter, AKEYCODE_DPAD_CENTER)
+KEY_MAP_ANDROID(Enter, AKEYCODE_ENTER)
+KEY_MAP_ANDROID(Enter, AKEYCODE_NUMPAD_ENTER)
+
+// Tab
+KEY_MAP_WIN(Tab, VK_TAB)
+KEY_MAP_COCOA(Tab, kVK_Tab)
+KEY_MAP_GTK(Tab, GDK_Tab)
+KEY_MAP_GTK(Tab, GDK_ISO_Left_Tab)  // Shift+Tab
+KEY_MAP_GTK(Tab, GDK_KP_Tab)
+KEY_MAP_ANDROID(Tab, AKEYCODE_TAB)
+
+/******************************************************************************
+ * Navigation Keys
+ ******************************************************************************/
+// ArrowDown
+KEY_MAP_WIN(ArrowDown, VK_DOWN)
+KEY_MAP_COCOA(ArrowDown, kVK_DownArrow)
+KEY_MAP_GTK(ArrowDown, GDK_Down)
+KEY_MAP_GTK(ArrowDown, GDK_KP_Down)
+KEY_MAP_ANDROID(ArrowDown, AKEYCODE_DPAD_DOWN)
+
+// ArrowLeft
+KEY_MAP_WIN(ArrowLeft, VK_LEFT)
+KEY_MAP_COCOA(ArrowLeft, kVK_LeftArrow)
+KEY_MAP_GTK(ArrowLeft, GDK_Left)
+KEY_MAP_GTK(ArrowLeft, GDK_KP_Left)
+KEY_MAP_ANDROID(ArrowLeft, AKEYCODE_DPAD_LEFT)
+
+// ArrowRight
+KEY_MAP_WIN(ArrowRight, VK_RIGHT)
+KEY_MAP_COCOA(ArrowRight, kVK_RightArrow)
+KEY_MAP_GTK(ArrowRight, GDK_Right)
+KEY_MAP_GTK(ArrowRight, GDK_KP_Right)
+KEY_MAP_ANDROID(ArrowRight, AKEYCODE_DPAD_RIGHT)
+
+// ArrowUp
+KEY_MAP_WIN(ArrowUp, VK_UP)
+KEY_MAP_COCOA(ArrowUp, kVK_UpArrow)
+KEY_MAP_GTK(ArrowUp, GDK_Up)
+KEY_MAP_GTK(ArrowUp, GDK_KP_Up)
+KEY_MAP_ANDROID(ArrowUp, AKEYCODE_DPAD_UP)
+
+// End
+KEY_MAP_WIN(End, VK_END)
+KEY_MAP_COCOA(End, kVK_End)
+KEY_MAP_GTK(End, GDK_End)
+KEY_MAP_GTK(End, GDK_KP_End)
+KEY_MAP_ANDROID(End, AKEYCODE_MOVE_END)
+
+// Home
+KEY_MAP_WIN(Home, VK_HOME)
+KEY_MAP_COCOA(Home, kVK_Home)
+KEY_MAP_GTK(Home, GDK_Home)
+KEY_MAP_GTK(Home, GDK_KP_Home)
+KEY_MAP_ANDROID(Home, AKEYCODE_MOVE_HOME)
+
+// PageDown
+KEY_MAP_WIN(PageDown, VK_NEXT)
+KEY_MAP_COCOA(PageDown, kVK_PageDown)
+KEY_MAP_GTK(PageDown, GDK_Page_Down /* same as GDK_Next */)
+KEY_MAP_GTK(PageDown, GDK_KP_Page_Down /* same as GDK_KP_Next */)
+KEY_MAP_ANDROID(PageDown, AKEYCODE_PAGE_DOWN)
+
+// PageUp
+KEY_MAP_WIN(PageUp, VK_PRIOR)
+KEY_MAP_COCOA(PageUp, kVK_PageUp)
+KEY_MAP_GTK(PageUp, GDK_Page_Up /* same as GDK_Prior */)
+KEY_MAP_GTK(PageUp, GDK_KP_Page_Up /* same as GDK_KP_Prior */)
+KEY_MAP_ANDROID(PageUp, AKEYCODE_PAGE_UP)
+
+/******************************************************************************
+ * Editing Keys
+ ******************************************************************************/
+// Backspace
+KEY_MAP_WIN(Backspace, VK_BACK)
+KEY_MAP_COCOA(Backspace, kVK_PC_Backspace)
+KEY_MAP_GTK(Backspace, GDK_BackSpace)
+KEY_MAP_ANDROID(Backspace, AKEYCODE_DEL)
+
+// Clear
+KEY_MAP_WIN(Clear, VK_CLEAR)
+KEY_MAP_WIN(Clear, VK_OEM_CLEAR)
+KEY_MAP_COCOA(Clear, kVK_ANSI_KeypadClear)
+KEY_MAP_GTK(Clear, GDK_Clear)
+KEY_MAP_ANDROID(Clear, AKEYCODE_CLEAR)
+
+// Copy
+KEY_MAP_WIN_CMD(Copy, APPCOMMAND_COPY)
+KEY_MAP_GTK(Copy, GDK_Copy)
+KEY_MAP_ANDROID(Copy, AKEYCODE_COPY)
+
+// CrSel
+KEY_MAP_WIN(CrSel, VK_CRSEL)
+KEY_MAP_GTK(CrSel, GDK_3270_CursorSelect)  // legacy IBM keyboard layout
+
+// Cut
+KEY_MAP_WIN_CMD(Cut, APPCOMMAND_CUT)
+KEY_MAP_GTK(Cut, GDK_Cut)
+KEY_MAP_ANDROID(Cut, AKEYCODE_CUT)
+
+// Delete
+KEY_MAP_WIN(Delete, VK_DELETE)
+KEY_MAP_COCOA(Delete, kVK_PC_Delete)
+KEY_MAP_GTK(Delete, GDK_Delete)
+KEY_MAP_GTK(Delete, GDK_KP_Delete)
+KEY_MAP_ANDROID(Delete, AKEYCODE_FORWARD_DEL)
+
+// EraseEof
+KEY_MAP_WIN(EraseEof, VK_EREOF)
+KEY_MAP_GTK(EraseEof, GDK_3270_EraseEOF)  // legacy IBM keyboard layout
+
+// ExSel
+KEY_MAP_WIN(ExSel, VK_EXSEL)
+KEY_MAP_GTK(ExSel, GDK_3270_ExSelect)  // legacy IBM keyboard layout
+
+// Insert
+KEY_MAP_WIN(Insert, VK_INSERT)
+KEY_MAP_GTK(Insert, GDK_Insert)
+KEY_MAP_GTK(Insert, GDK_KP_Insert)
+KEY_MAP_ANDROID(Insert, AKEYCODE_INSERT)
+
+// Paste
+KEY_MAP_WIN_CMD(Paste, APPCOMMAND_PASTE)
+KEY_MAP_GTK(Paste, GDK_Paste)
+KEY_MAP_ANDROID(Paste, AKEYCODE_PASTE)
+
+// Redo
+KEY_MAP_WIN_CMD(Redo, APPCOMMAND_REDO)
+KEY_MAP_GTK(Redo, GDK_Redo)
+
+// Undo
+KEY_MAP_WIN_CMD(Undo, APPCOMMAND_UNDO)
+KEY_MAP_GTK(Undo, GDK_Undo)
+
+/******************************************************************************
+ * UI Keys
+ ******************************************************************************/
+// Accept
+KEY_MAP_WIN(Accept, VK_ACCEPT)
+
+// Attn
+KEY_MAP_WIN_OTH(Attn, VK_ATTN)    // not valid with Japanese keyboard layout
+KEY_MAP_GTK(Attn, GDK_3270_Attn)  // legacy IBM keyboard layout
+
+// Cancel
+KEY_MAP_WIN(Cancel, VK_CANCEL)
+KEY_MAP_GTK(Cancel, GDK_Cancel)
+
+// ContextMenu
+KEY_MAP_WIN(ContextMenu, VK_APPS)
+KEY_MAP_COCOA(ContextMenu, kVK_PC_ContextMenu)
+KEY_MAP_GTK(ContextMenu, GDK_Menu)
+KEY_MAP_ANDROID(ContextMenu, AKEYCODE_MENU)
+
+// Escape
+KEY_MAP_WIN(Escape, VK_ESCAPE)
+KEY_MAP_COCOA(Escape, kVK_Escape)
+KEY_MAP_GTK(Escape, GDK_Escape)
+KEY_MAP_ANDROID(Escape, AKEYCODE_ESCAPE)
+
+// Execute
+KEY_MAP_WIN(Execute, VK_EXECUTE)
+KEY_MAP_GTK(Execute, GDK_Execute)
+
+// Find
+KEY_MAP_WIN_CMD(Find, APPCOMMAND_FIND)
+KEY_MAP_GTK(Find, GDK_Find)
+
+// Help
+KEY_MAP_WIN(Help, VK_HELP)
+KEY_MAP_WIN_CMD(Help, APPCOMMAND_HELP)
+KEY_MAP_COCOA(Help, kVK_Help)
+KEY_MAP_GTK(Help, GDK_Help)
+KEY_MAP_ANDROID(Help, AKEYCODE_HELP)
+
+// Pause
+KEY_MAP_WIN(Pause, VK_PAUSE)
+KEY_MAP_GTK(Pause, GDK_Pause)
+// Break is typically mapped to Alt+Pause or Ctrl+Pause on GTK.
+KEY_MAP_GTK(Pause, GDK_Break)
+KEY_MAP_ANDROID(Pause, AKEYCODE_BREAK)
+
+// Play
+KEY_MAP_WIN(Play, VK_PLAY)
+KEY_MAP_GTK(Play, GDK_3270_Play)  // legacy IBM keyboard layout
+
+// Select
+KEY_MAP_WIN(Select, VK_SELECT)
+KEY_MAP_GTK(Select, GDK_Select)
+
+// ZoomIn
+KEY_MAP_GTK(ZoomIn, GDK_ZoomIn)
+KEY_MAP_ANDROID(ZoomIn, AKEYCODE_ZOOM_IN)
+
+// ZoomOut
+KEY_MAP_GTK(ZoomOut, GDK_ZoomOut)
+KEY_MAP_ANDROID(ZoomOut, AKEYCODE_ZOOM_OUT)
+
+/******************************************************************************
+ * Device Keys
+ ******************************************************************************/
+// BrightnessDown
+KEY_MAP_GTK(BrightnessDown, GDK_MonBrightnessDown)
+KEY_MAP_ANDROID(BrightnessDown, AKEYCODE_BRIGHTNESS_DOWN)
+
+// BrightnessUp
+KEY_MAP_GTK(BrightnessUp, GDK_MonBrightnessUp)
+KEY_MAP_ANDROID(BrightnessUp, AKEYCODE_BRIGHTNESS_UP)
+
+// Eject
+KEY_MAP_GTK(Eject, GDK_Eject)
+KEY_MAP_ANDROID(Eject, AKEYCODE_MEDIA_EJECT)
+
+// LogOff
+KEY_MAP_GTK(LogOff, GDK_LogOff)
+
+// Power
+KEY_MAP_ANDROID(Power, AKEYCODE_POWER)
+
+// PowerOff
+KEY_MAP_GTK(PowerOff, GDK_PowerDown)
+KEY_MAP_GTK(PowerOff, GDK_PowerOff)
+
+// PrintScreen
+KEY_MAP_WIN(PrintScreen, VK_SNAPSHOT)
+KEY_MAP_GTK(PrintScreen, GDK_3270_PrintScreen)
+KEY_MAP_GTK(PrintScreen, GDK_Print)
+KEY_MAP_GTK(PrintScreen, GDK_Sys_Req)
+KEY_MAP_ANDROID(PrintScreen, AKEYCODE_SYSRQ)
+
+// Hibernate
+KEY_MAP_GTK(Hibernate, GDK_Hibernate)
+
+// Standby
+KEY_MAP_WIN(Standby, VK_SLEEP)
+KEY_MAP_GTK(Standby, GDK_Standby)
+KEY_MAP_GTK(Standby, GDK_Suspend)
+KEY_MAP_GTK(Standby, GDK_Sleep)
+KEY_MAP_ANDROID(Standby, AKEYCODE_SLEEP)
+
+// WakeUp
+KEY_MAP_GTK(WakeUp, GDK_WakeUp)
+KEY_MAP_ANDROID(WakeUp, AKEYCODE_WAKEUP)
+
+/******************************************************************************
+ * IME and Composition Keys
+ ******************************************************************************/
+// AllCandidates
+KEY_MAP_GTK(AllCandidates, GDK_MultipleCandidate)  // OADG 109, Zen Koho
+
+// Alphanumeric
+KEY_MAP_WIN_JPN(Alphanumeric, VK_OEM_ATTN)
+KEY_MAP_GTK(Alphanumeric, GDK_Eisu_Shift)
+KEY_MAP_GTK(Alphanumeric, GDK_Eisu_toggle)
+
+// CodeInput
+KEY_MAP_GTK(CodeInput, GDK_Codeinput)  // OADG 109, Kanji Bangou
+
+// Compose
+KEY_MAP_GTK(Compose, GDK_Multi_key)  // "Multi Key" is "Compose key" on X
+
+// Convert
+KEY_MAP_WIN(Convert, VK_CONVERT)
+KEY_MAP_GTK(Convert, GDK_Henkan)
+KEY_MAP_ANDROID(Convert, AKEYCODE_HENKAN)
+
+// Dead
+KEY_MAP_GTK(Dead, GDK_dead_grave)
+KEY_MAP_GTK(Dead, GDK_dead_acute)
+KEY_MAP_GTK(Dead, GDK_dead_circumflex)
+KEY_MAP_GTK(Dead, GDK_dead_tilde)  // Same as GDK_dead_perispomeni
+KEY_MAP_GTK(Dead, GDK_dead_macron)
+KEY_MAP_GTK(Dead, GDK_dead_breve)
+KEY_MAP_GTK(Dead, GDK_dead_abovedot)
+KEY_MAP_GTK(Dead, GDK_dead_diaeresis)
+KEY_MAP_GTK(Dead, GDK_dead_abovering)
+KEY_MAP_GTK(Dead, GDK_dead_doubleacute)
+KEY_MAP_GTK(Dead, GDK_dead_caron)
+KEY_MAP_GTK(Dead, GDK_dead_cedilla)
+KEY_MAP_GTK(Dead, GDK_dead_ogonek)
+KEY_MAP_GTK(Dead, GDK_dead_iota)
+KEY_MAP_GTK(Dead, GDK_dead_voiced_sound)
+KEY_MAP_GTK(Dead, GDK_dead_semivoiced_sound)
+KEY_MAP_GTK(Dead, GDK_dead_belowdot)
+KEY_MAP_GTK(Dead, GDK_dead_hook)
+KEY_MAP_GTK(Dead, GDK_dead_horn)
+KEY_MAP_GTK(Dead, GDK_dead_stroke)
+KEY_MAP_GTK(Dead, GDK_dead_abovecomma)          // Same as GDK_dead_psili
+KEY_MAP_GTK(Dead, GDK_dead_abovereversedcomma)  // Same as GDK_dead_dasia
+KEY_MAP_GTK(Dead, GDK_dead_doublegrave)
+KEY_MAP_GTK(Dead, GDK_dead_belowring)
+KEY_MAP_GTK(Dead, GDK_dead_belowmacron)
+KEY_MAP_GTK(Dead, GDK_dead_belowcircumflex)
+KEY_MAP_GTK(Dead, GDK_dead_belowtilde)
+KEY_MAP_GTK(Dead, GDK_dead_belowbreve)
+KEY_MAP_GTK(Dead, GDK_dead_belowdiaeresis)
+KEY_MAP_GTK(Dead, GDK_dead_invertedbreve)
+KEY_MAP_GTK(Dead, GDK_dead_belowcomma)
+KEY_MAP_GTK(Dead, GDK_dead_currency)
+KEY_MAP_GTK(Dead, GDK_dead_a)
+KEY_MAP_GTK(Dead, GDK_dead_A)
+KEY_MAP_GTK(Dead, GDK_dead_e)
+KEY_MAP_GTK(Dead, GDK_dead_E)
+KEY_MAP_GTK(Dead, GDK_dead_i)
+KEY_MAP_GTK(Dead, GDK_dead_I)
+KEY_MAP_GTK(Dead, GDK_dead_o)
+KEY_MAP_GTK(Dead, GDK_dead_O)
+KEY_MAP_GTK(Dead, GDK_dead_u)
+KEY_MAP_GTK(Dead, GDK_dead_U)
+KEY_MAP_GTK(Dead, GDK_dead_small_schwa)
+KEY_MAP_GTK(Dead, GDK_dead_capital_schwa)
+KEY_MAP_GTK(Dead, GDK_dead_greek)
+
+// FinalMode
+KEY_MAP_WIN(FinalMode, VK_FINAL)
+
+// GroupFirst
+KEY_MAP_GTK(GroupFirst, GDK_ISO_First_Group)
+
+// GroupLast
+KEY_MAP_GTK(GroupLast, GDK_ISO_Last_Group)
+
+// GroupNext
+KEY_MAP_GTK(GroupNext, GDK_ISO_Next_Group)
+KEY_MAP_ANDROID(GroupNext, AKEYCODE_LANGUAGE_SWITCH)
+
+// GroupPrevious
+KEY_MAP_GTK(GroupPrevious, GDK_ISO_Prev_Group)
+
+// ModeChange
+KEY_MAP_WIN(ModeChange, VK_MODECHANGE)
+KEY_MAP_ANDROID(ModeChange, AKEYCODE_SWITCH_CHARSET)
+
+// NonConvert
+KEY_MAP_WIN(NonConvert, VK_NONCONVERT)
+KEY_MAP_GTK(NonConvert, GDK_Muhenkan)
+KEY_MAP_ANDROID(NonConvert, AKEYCODE_MUHENKAN)
+
+// PreviousCandidate
+KEY_MAP_GTK(PreviousCandidate, GDK_PreviousCandidate)  // OADG 109, Mae Koho
+
+// Process
+KEY_MAP_WIN(Process, VK_PROCESSKEY)
+
+// SingleCandidate
+KEY_MAP_GTK(SingleCandidate, GDK_SingleCandidate)
+
+/******************************************************************************
+ * Keys specific to Korean keyboards
+ ******************************************************************************/
+// HangulMode
+KEY_MAP_WIN_KOR(HangulMode, VK_HANGUL /* same as VK_KANA */)
+
+// HanjaMode
+KEY_MAP_WIN_KOR(HanjaMode, VK_HANJA /* same as VK_KANJI */)
+
+// JunjaMode
+KEY_MAP_WIN(JunjaMode, VK_JUNJA)
+
+/******************************************************************************
+ * Keys specific to Japanese keyboards
+ ******************************************************************************/
+// Eisu
+KEY_MAP_COCOA(Eisu, kVK_JIS_Eisu)
+KEY_MAP_ANDROID(Eisu, AKEYCODE_EISU)
+
+// Hankaku
+KEY_MAP_WIN_JPN(Hankaku, VK_OEM_AUTO)
+KEY_MAP_GTK(Hankaku, GDK_Hankaku)
+
+// Hiragana
+KEY_MAP_WIN_JPN(Hiragana, VK_OEM_COPY)
+KEY_MAP_GTK(Hiragana, GDK_Hiragana)
+
+// HiraganaKatakana
+KEY_MAP_GTK(HiraganaKatakana, GDK_Hiragana_Katakana)
+KEY_MAP_ANDROID(HiraganaKatakana, AKEYCODE_KATAKANA_HIRAGANA)
+
+// KanaMode
+// VK_KANA is never used with modern Japanese keyboard, however, IE maps it to
+// KanaMode, therefore, we should use same map for it.
+KEY_MAP_WIN_JPN(KanaMode, VK_KANA /* same as VK_HANGUL */)
+KEY_MAP_WIN_JPN(KanaMode, VK_ATTN)
+KEY_MAP_GTK(KanaMode, GDK_Kana_Lock)
+KEY_MAP_GTK(KanaMode, GDK_Kana_Shift)
+
+// KanjiMode
+KEY_MAP_WIN_JPN(KanjiMode, VK_KANJI /* same as VK_HANJA */)
+KEY_MAP_COCOA(KanjiMode, kVK_JIS_Kana)  // Kana key opens IME
+KEY_MAP_GTK(KanjiMode, GDK_Kanji)       // Typically, Alt + Hankaku/Zenkaku key
+// Assuming that KANA key of Android is the Kana key on Mac keyboard.
+KEY_MAP_ANDROID(KanjiMode, AKEYCODE_KANA)
+
+// Katakana
+KEY_MAP_WIN_JPN(Katakana, VK_OEM_FINISH)
+KEY_MAP_GTK(Katakana, GDK_Katakana)
+
+// Romaji
+KEY_MAP_WIN_JPN(Romaji, VK_OEM_BACKTAB)
+KEY_MAP_GTK(Romaji, GDK_Romaji)
+
+// Zenkaku
+KEY_MAP_WIN_JPN(Zenkaku, VK_OEM_ENLW)
+KEY_MAP_GTK(Zenkaku, GDK_Zenkaku)
+
+// ZenkakuHankaku
+KEY_MAP_GTK(ZenkakuHankaku, GDK_Zenkaku_Hankaku)
+KEY_MAP_ANDROID(ZenkakuHankaku, AKEYCODE_ZENKAKU_HANKAKU)
+
+/******************************************************************************
+ * General-Purpose Function Keys
+ ******************************************************************************/
+// F1
+KEY_MAP_WIN(F1, VK_F1)
+KEY_MAP_COCOA(F1, kVK_F1)
+KEY_MAP_GTK(F1, GDK_F1)
+KEY_MAP_GTK(F1, GDK_KP_F1)
+KEY_MAP_ANDROID(F1, AKEYCODE_F1)
+
+// F2
+KEY_MAP_WIN(F2, VK_F2)
+KEY_MAP_COCOA(F2, kVK_F2)
+KEY_MAP_GTK(F2, GDK_F2)
+KEY_MAP_GTK(F2, GDK_KP_F2)
+KEY_MAP_ANDROID(F2, AKEYCODE_F2)
+
+// F3
+KEY_MAP_WIN(F3, VK_F3)
+KEY_MAP_COCOA(F3, kVK_F3)
+KEY_MAP_GTK(F3, GDK_F3)
+KEY_MAP_GTK(F3, GDK_KP_F3)
+KEY_MAP_ANDROID(F3, AKEYCODE_F3)
+
+// F4
+KEY_MAP_WIN(F4, VK_F4)
+KEY_MAP_COCOA(F4, kVK_F4)
+KEY_MAP_GTK(F4, GDK_F4)
+KEY_MAP_GTK(F4, GDK_KP_F4)
+KEY_MAP_ANDROID(F4, AKEYCODE_F4)
+
+// F5
+KEY_MAP_WIN(F5, VK_F5)
+KEY_MAP_COCOA(F5, kVK_F5)
+KEY_MAP_GTK(F5, GDK_F5)
+KEY_MAP_ANDROID(F5, AKEYCODE_F5)
+
+// F6
+KEY_MAP_WIN(F6, VK_F6)
+KEY_MAP_COCOA(F6, kVK_F6)
+KEY_MAP_GTK(F6, GDK_F6)
+KEY_MAP_ANDROID(F6, AKEYCODE_F6)
+
+// F7
+KEY_MAP_WIN(F7, VK_F7)
+KEY_MAP_COCOA(F7, kVK_F7)
+KEY_MAP_GTK(F7, GDK_F7)
+KEY_MAP_ANDROID(F7, AKEYCODE_F7)
+
+// F8
+KEY_MAP_WIN(F8, VK_F8)
+KEY_MAP_COCOA(F8, kVK_F8)
+KEY_MAP_GTK(F8, GDK_F8)
+KEY_MAP_ANDROID(F8, AKEYCODE_F8)
+
+// F9
+KEY_MAP_WIN(F9, VK_F9)
+KEY_MAP_COCOA(F9, kVK_F9)
+KEY_MAP_GTK(F9, GDK_F9)
+KEY_MAP_ANDROID(F9, AKEYCODE_F9)
+
+// F10
+KEY_MAP_WIN(F10, VK_F10)
+KEY_MAP_COCOA(F10, kVK_F10)
+KEY_MAP_GTK(F10, GDK_F10)
+KEY_MAP_ANDROID(F10, AKEYCODE_F10)
+
+// F11
+KEY_MAP_WIN(F11, VK_F11)
+KEY_MAP_COCOA(F11, kVK_F11)
+KEY_MAP_GTK(F11, GDK_F11 /* same as GDK_L1 */)
+KEY_MAP_ANDROID(F11, AKEYCODE_F11)
+
+// F12
+KEY_MAP_WIN(F12, VK_F12)
+KEY_MAP_COCOA(F12, kVK_F12)
+KEY_MAP_GTK(F12, GDK_F12 /* same as GDK_L2 */)
+KEY_MAP_ANDROID(F12, AKEYCODE_F12)
+
+// F13
+KEY_MAP_WIN(F13, VK_F13)
+KEY_MAP_COCOA(F13, kVK_F13)
+KEY_MAP_GTK(F13, GDK_F13 /* same as GDK_L3 */)
+
+// F14
+KEY_MAP_WIN(F14, VK_F14)
+KEY_MAP_COCOA(F14, kVK_F14)
+KEY_MAP_GTK(F14, GDK_F14 /* same as GDK_L4 */)
+
+// F15
+KEY_MAP_WIN(F15, VK_F15)
+KEY_MAP_COCOA(F15, kVK_F15)
+KEY_MAP_GTK(F15, GDK_F15 /* same as GDK_L5 */)
+
+// F16
+KEY_MAP_WIN(F16, VK_F16)
+KEY_MAP_COCOA(F16, kVK_F16)
+KEY_MAP_GTK(F16, GDK_F16 /* same as GDK_L6 */)
+
+// F17
+KEY_MAP_WIN(F17, VK_F17)
+KEY_MAP_COCOA(F17, kVK_F17)
+KEY_MAP_GTK(F17, GDK_F17 /* same as GDK_L7 */)
+
+// F18
+KEY_MAP_WIN(F18, VK_F18)
+KEY_MAP_COCOA(F18, kVK_F18)
+KEY_MAP_GTK(F18, GDK_F18 /* same as GDK_L8 */)
+
+// F19
+KEY_MAP_WIN(F19, VK_F19)
+KEY_MAP_COCOA(F19, kVK_F19)
+KEY_MAP_GTK(F19, GDK_F19 /* same as GDK_L9 */)
+
+// F20
+KEY_MAP_WIN(F20, VK_F20)
+KEY_MAP_GTK(F20, GDK_F20 /* same as GDK_L10 */)
+
+// F21
+KEY_MAP_WIN(F21, VK_F21)
+KEY_MAP_GTK(F21, GDK_F21 /* same as GDK_R1 */)
+
+// F22
+KEY_MAP_WIN(F22, VK_F22)
+KEY_MAP_GTK(F22, GDK_F22 /* same as GDK_R2 */)
+
+// F23
+KEY_MAP_WIN(F23, VK_F23)
+KEY_MAP_GTK(F23, GDK_F23 /* same as GDK_R3 */)
+
+// F24
+KEY_MAP_WIN(F24, VK_F24)
+KEY_MAP_GTK(F24, GDK_F24 /* same as GDK_R4 */)
+
+// F25
+KEY_MAP_GTK(F25, GDK_F25 /* same as GDK_R5 */)
+
+// F26
+KEY_MAP_GTK(F26, GDK_F26 /* same as GDK_R6 */)
+
+// F27
+KEY_MAP_GTK(F27, GDK_F27 /* same as GDK_R7 */)
+
+// F28
+KEY_MAP_GTK(F28, GDK_F28 /* same as GDK_R8 */)
+
+// F29
+KEY_MAP_GTK(F29, GDK_F29 /* same as GDK_R9 */)
+
+// F30
+KEY_MAP_GTK(F30, GDK_F30 /* same as GDK_R10 */)
+
+// F31
+KEY_MAP_GTK(F31, GDK_F31 /* same as GDK_R11 */)
+
+// F32
+KEY_MAP_GTK(F32, GDK_F32 /* same as GDK_R12 */)
+
+// F33
+KEY_MAP_GTK(F33, GDK_F33 /* same as GDK_R13 */)
+
+// F34
+KEY_MAP_GTK(F34, GDK_F34 /* same as GDK_R14 */)
+
+// F35
+KEY_MAP_GTK(F35, GDK_F35 /* same as GDK_R15 */)
+
+/******************************************************************************
+ * Multimedia Keys
+ ******************************************************************************/
+// ChannelDown
+KEY_MAP_WIN_CMD(ChannelDown, APPCOMMAND_MEDIA_CHANNEL_DOWN)
+KEY_MAP_ANDROID(ChannelDown, AKEYCODE_CHANNEL_DOWN)
+
+// ChannelUp
+KEY_MAP_WIN_CMD(ChannelUp, APPCOMMAND_MEDIA_CHANNEL_UP)
+KEY_MAP_ANDROID(ChannelUp, AKEYCODE_CHANNEL_UP)
+
+// Close
+// NOTE: This is not a key to close disk tray, this is a key to close document
+//       or window.
+KEY_MAP_WIN_CMD(Close, APPCOMMAND_CLOSE)
+KEY_MAP_GTK(Close, GDK_Close)
+
+// MailForward
+KEY_MAP_WIN_CMD(MailForward, APPCOMMAND_FORWARD_MAIL)
+KEY_MAP_GTK(MailForward, GDK_MailForward)
+
+// MailReply
+KEY_MAP_WIN_CMD(MailReply, APPCOMMAND_REPLY_TO_MAIL)
+KEY_MAP_GTK(MailReply, GDK_Reply)
+
+// MailSend
+KEY_MAP_WIN_CMD(MailSend, APPCOMMAND_SEND_MAIL)
+KEY_MAP_GTK(MailSend, GDK_Send)
+
+// MediaFastForward
+KEY_MAP_WIN_CMD(MediaFastForward, APPCOMMAND_MEDIA_FAST_FORWARD)
+KEY_MAP_GTK(MediaFastForward, GDK_AudioForward)
+KEY_MAP_ANDROID(MediaFastForward, AKEYCODE_MEDIA_FAST_FORWARD)
+
+// MediaPause
+KEY_MAP_WIN_CMD(MediaPause, APPCOMMAND_MEDIA_PAUSE)
+KEY_MAP_GTK(MediaPause, GDK_AudioPause)
+KEY_MAP_ANDROID(MediaPause, AKEYCODE_MEDIA_PAUSE)
+
+// MediaPlay
+KEY_MAP_WIN_CMD(MediaPlay, APPCOMMAND_MEDIA_PLAY)
+KEY_MAP_GTK(MediaPlay, GDK_AudioPlay)
+KEY_MAP_ANDROID(MediaPlay, AKEYCODE_MEDIA_PLAY)
+
+// MediaPlayPause
+KEY_MAP_WIN(MediaPlayPause, VK_MEDIA_PLAY_PAUSE)
+KEY_MAP_WIN_CMD(MediaPlayPause, APPCOMMAND_MEDIA_PLAY_PAUSE)
+KEY_MAP_ANDROID(MediaPlayPause, AKEYCODE_MEDIA_PLAY_PAUSE)
+
+// MediaRecord
+KEY_MAP_WIN_CMD(MediaRecord, APPCOMMAND_MEDIA_RECORD)
+KEY_MAP_GTK(MediaRecord, GDK_AudioRecord)
+KEY_MAP_ANDROID(MediaRecord, AKEYCODE_MEDIA_RECORD)
+
+// MediaRewind
+KEY_MAP_WIN_CMD(MediaRewind, APPCOMMAND_MEDIA_REWIND)
+KEY_MAP_GTK(MediaRewind, GDK_AudioRewind)
+KEY_MAP_ANDROID(MediaRewind, AKEYCODE_MEDIA_REWIND)
+
+// MediaStop
+KEY_MAP_WIN(MediaStop, VK_MEDIA_STOP)
+KEY_MAP_WIN_CMD(MediaStop, APPCOMMAND_MEDIA_STOP)
+KEY_MAP_GTK(MediaStop, GDK_AudioStop)
+KEY_MAP_ANDROID(MediaStop, AKEYCODE_MEDIA_STOP)
+
+// MediaTrackNext
+KEY_MAP_WIN(MediaTrackNext, VK_MEDIA_NEXT_TRACK)
+KEY_MAP_WIN_CMD(MediaTrackNext, APPCOMMAND_MEDIA_NEXTTRACK)
+KEY_MAP_GTK(MediaTrackNext, GDK_AudioNext)
+KEY_MAP_ANDROID(MediaTrackNext, AKEYCODE_MEDIA_NEXT)
+
+// MediaTrackPrevious
+KEY_MAP_WIN(MediaTrackPrevious, VK_MEDIA_PREV_TRACK)
+KEY_MAP_WIN_CMD(MediaTrackPrevious, APPCOMMAND_MEDIA_PREVIOUSTRACK)
+KEY_MAP_GTK(MediaTrackPrevious, GDK_AudioPrev)
+KEY_MAP_ANDROID(MediaTrackPrevious, AKEYCODE_MEDIA_PREVIOUS)
+
+// New
+KEY_MAP_WIN_CMD(New, APPCOMMAND_NEW)
+KEY_MAP_GTK(New, GDK_New)
+
+// Open
+KEY_MAP_WIN_CMD(Open, APPCOMMAND_OPEN)
+KEY_MAP_GTK(Open, GDK_Open)
+
+// Print
+KEY_MAP_WIN_CMD(Print, APPCOMMAND_PRINT)
+
+// Save
+KEY_MAP_WIN_CMD(Save, APPCOMMAND_SAVE)
+KEY_MAP_GTK(Save, GDK_Save)
+
+// SpellCheck
+KEY_MAP_WIN_CMD(SpellCheck, APPCOMMAND_SPELL_CHECK)
+KEY_MAP_GTK(SpellCheck, GDK_Spell)
+
+/******************************************************************************
+ * Audio Keys
+ *****************************************************************************/
+// AudioBassBoostDown
+KEY_MAP_WIN_CMD(AudioBassBoostDown, APPCOMMAND_BASS_DOWN)
+
+// AudioBassBoostUp
+KEY_MAP_WIN_CMD(AudioBassBoostUp, APPCOMMAND_BASS_UP)
+
+// AudioVolumeDown
+KEY_MAP_WIN(AudioVolumeDown, VK_VOLUME_DOWN)
+KEY_MAP_WIN_CMD(AudioVolumeDown, APPCOMMAND_VOLUME_DOWN)
+KEY_MAP_COCOA(AudioVolumeDown, kVK_VolumeDown)
+KEY_MAP_GTK(AudioVolumeDown, GDK_AudioLowerVolume)
+KEY_MAP_ANDROID(AudioVolumeDown, AKEYCODE_VOLUME_DOWN)
+
+// AudioVolumeUp
+KEY_MAP_WIN(AudioVolumeUp, VK_VOLUME_UP)
+KEY_MAP_WIN_CMD(AudioVolumeUp, APPCOMMAND_VOLUME_UP)
+KEY_MAP_COCOA(AudioVolumeUp, kVK_VolumeUp)
+KEY_MAP_GTK(AudioVolumeUp, GDK_AudioRaiseVolume)
+KEY_MAP_ANDROID(AudioVolumeUp, AKEYCODE_VOLUME_UP)
+
+// AudioVolumeMute
+KEY_MAP_WIN(AudioVolumeMute, VK_VOLUME_MUTE)
+KEY_MAP_WIN_CMD(AudioVolumeMute, APPCOMMAND_VOLUME_MUTE)
+KEY_MAP_COCOA(AudioVolumeMute, kVK_Mute)
+KEY_MAP_GTK(AudioVolumeMute, GDK_AudioMute)
+KEY_MAP_ANDROID(AudioVolumeMute, AKEYCODE_VOLUME_MUTE)
+
+// MicrophoneVolumeMute
+KEY_MAP_ANDROID(MicrophoneVolumeMute, AKEYCODE_MUTE)
+
+/******************************************************************************
+ * Application Keys
+ ******************************************************************************/
+// LaunchCalculator
+KEY_MAP_GTK(LaunchCalculator, GDK_Calculator)
+KEY_MAP_ANDROID(LaunchCalculator, AKEYCODE_CALCULATOR)
+
+// LaunchCalendar
+KEY_MAP_GTK(LaunchCalendar, GDK_Calendar)
+KEY_MAP_ANDROID(LaunchCalendar, AKEYCODE_CALENDAR)
+
+// LaunchContacts
+KEY_MAP_ANDROID(LaunchContacts, AKEYCODE_CONTACTS)
+
+// LaunchMail
+KEY_MAP_WIN(LaunchMail, VK_LAUNCH_MAIL)
+KEY_MAP_WIN_CMD(LaunchMail, APPCOMMAND_LAUNCH_MAIL)
+KEY_MAP_GTK(LaunchMail, GDK_Mail)
+KEY_MAP_ANDROID(LaunchMail, AKEYCODE_ENVELOPE)
+
+// LaunchMediaPlayer
+KEY_MAP_WIN(LaunchMediaPlayer, VK_LAUNCH_MEDIA_SELECT)
+KEY_MAP_WIN_CMD(LaunchMediaPlayer, APPCOMMAND_LAUNCH_MEDIA_SELECT)
+// GDK_CD is defined as "Launch CD/DVD player" in XF86keysym.h.
+// Therefore, let's map it to media player rather than music player.
+KEY_MAP_GTK(LaunchMediaPlayer, GDK_CD)
+KEY_MAP_GTK(LaunchMediaPlayer, GDK_Video)
+KEY_MAP_GTK(LaunchMediaPlayer, GDK_AudioMedia)
+
+// LaunchMusicPlayer
+KEY_MAP_GTK(LaunchMusicPlayer, GDK_Music)
+KEY_MAP_ANDROID(LaunchMusicPlayer, AKEYCODE_MUSIC)
+
+// LaunchMyComputer
+KEY_MAP_GTK(LaunchMyComputer, GDK_MyComputer)
+KEY_MAP_GTK(LaunchMyComputer, GDK_Explorer)
+
+// LaunchScreenSaver
+KEY_MAP_GTK(LaunchScreenSaver, GDK_ScreenSaver)
+
+// LaunchSpreadsheet
+KEY_MAP_GTK(LaunchSpreadsheet, GDK_Excel)
+
+// LaunchWebBrowser
+KEY_MAP_GTK(LaunchWebBrowser, GDK_WWW)
+KEY_MAP_ANDROID(LaunchWebBrowser, AKEYCODE_EXPLORER)
+
+// LaunchWebCam
+KEY_MAP_GTK(LaunchWebCam, GDK_WebCam)
+
+// LaunchWordProcessor
+KEY_MAP_GTK(LaunchWordProcessor, GDK_Word)
+
+// LaunchApplication1
+KEY_MAP_WIN(LaunchApplication1, VK_LAUNCH_APP1)
+KEY_MAP_WIN_CMD(LaunchApplication1, APPCOMMAND_LAUNCH_APP1)
+KEY_MAP_GTK(LaunchApplication1, GDK_Launch0)
+
+// LaunchApplication2
+KEY_MAP_WIN(LaunchApplication2, VK_LAUNCH_APP2)
+KEY_MAP_WIN_CMD(LaunchApplication2, APPCOMMAND_LAUNCH_APP2)
+KEY_MAP_GTK(LaunchApplication2, GDK_Launch1)
+
+// LaunchApplication3
+KEY_MAP_GTK(LaunchApplication3, GDK_Launch2)
+
+// LaunchApplication4
+KEY_MAP_GTK(LaunchApplication4, GDK_Launch3)
+
+// LaunchApplication5
+KEY_MAP_GTK(LaunchApplication5, GDK_Launch4)
+
+// LaunchApplication6
+KEY_MAP_GTK(LaunchApplication6, GDK_Launch5)
+
+// LaunchApplication7
+KEY_MAP_GTK(LaunchApplication7, GDK_Launch6)
+
+// LaunchApplication8
+KEY_MAP_GTK(LaunchApplication8, GDK_Launch7)
+
+// LaunchApplication9
+KEY_MAP_GTK(LaunchApplication9, GDK_Launch8)
+
+// LaunchApplication10
+KEY_MAP_GTK(LaunchApplication10, GDK_Launch9)
+
+// LaunchApplication11
+KEY_MAP_GTK(LaunchApplication11, GDK_LaunchA)
+
+// LaunchApplication12
+KEY_MAP_GTK(LaunchApplication12, GDK_LaunchB)
+
+// LaunchApplication13
+KEY_MAP_GTK(LaunchApplication13, GDK_LaunchC)
+
+// LaunchApplication14
+KEY_MAP_GTK(LaunchApplication14, GDK_LaunchD)
+
+// LaunchApplication15
+KEY_MAP_GTK(LaunchApplication15, GDK_LaunchE)
+
+// LaunchApplication16
+KEY_MAP_GTK(LaunchApplication16, GDK_LaunchF)
+
+// LaunchApplication17
+
+// LaunchApplication18
+
+/******************************************************************************
+ * Browser Keys
+ ******************************************************************************/
+// BrowserBack
+KEY_MAP_WIN(BrowserBack, VK_BROWSER_BACK)
+KEY_MAP_WIN_CMD(BrowserBack, APPCOMMAND_BROWSER_BACKWARD)
+KEY_MAP_GTK(BrowserBack, GDK_Back)
+
+// BrowserFavorites
+KEY_MAP_WIN(BrowserFavorites, VK_BROWSER_FAVORITES)
+KEY_MAP_WIN_CMD(BrowserFavorites, APPCOMMAND_BROWSER_FAVORITES)
+KEY_MAP_ANDROID(BrowserFavorites, AKEYCODE_BOOKMARK)
+
+// BrowserForward
+KEY_MAP_WIN(BrowserForward, VK_BROWSER_FORWARD)
+KEY_MAP_WIN_CMD(BrowserForward, APPCOMMAND_BROWSER_FORWARD)
+KEY_MAP_GTK(BrowserForward, GDK_Forward)
+KEY_MAP_ANDROID(BrowserForward, AKEYCODE_FORWARD)
+
+// BrowserHome
+KEY_MAP_WIN(BrowserHome, VK_BROWSER_HOME)
+KEY_MAP_WIN_CMD(BrowserHome, APPCOMMAND_BROWSER_HOME)
+KEY_MAP_GTK(BrowserHome, GDK_HomePage)
+
+// BrowserRefresh
+KEY_MAP_WIN(BrowserRefresh, VK_BROWSER_REFRESH)
+KEY_MAP_WIN_CMD(BrowserRefresh, APPCOMMAND_BROWSER_REFRESH)
+KEY_MAP_GTK(BrowserRefresh, GDK_Refresh)
+KEY_MAP_GTK(BrowserRefresh, GDK_Reload)
+
+// BrowserSearch
+KEY_MAP_WIN(BrowserSearch, VK_BROWSER_SEARCH)
+KEY_MAP_WIN_CMD(BrowserSearch, APPCOMMAND_BROWSER_SEARCH)
+KEY_MAP_GTK(BrowserSearch, GDK_Search)
+KEY_MAP_ANDROID(BrowserSearch, AKEYCODE_SEARCH)
+
+// BrowserStop
+KEY_MAP_WIN(BrowserStop, VK_BROWSER_STOP)
+KEY_MAP_WIN_CMD(BrowserStop, APPCOMMAND_BROWSER_STOP)
+KEY_MAP_GTK(BrowserStop, GDK_Stop)
+
+/******************************************************************************
+ * Mobile Phone Keys
+ ******************************************************************************/
+// AppSwitch
+KEY_MAP_ANDROID(AppSwitch, AKEYCODE_APP_SWITCH)
+
+// Call
+KEY_MAP_ANDROID(Call, AKEYCODE_CALL)
+
+// Camera
+KEY_MAP_ANDROID(Camera, AKEYCODE_CAMERA)
+
+// CameraFocus
+KEY_MAP_ANDROID(CameraFocus, AKEYCODE_FOCUS)
+
+// EndCall
+KEY_MAP_ANDROID(EndCall, AKEYCODE_ENDCALL)
+
+// GoBack
+KEY_MAP_ANDROID(GoBack, AKEYCODE_BACK)
+
+// GoHome
+KEY_MAP_ANDROID(GoHome, AKEYCODE_HOME)
+
+// HeadsetHook
+KEY_MAP_ANDROID(HeadsetHook, AKEYCODE_HEADSETHOOK)
+
+// Notification
+KEY_MAP_ANDROID(Notification, AKEYCODE_NOTIFICATION)
+
+// MannerMode
+KEY_MAP_ANDROID(MannerMode, AKEYCODE_MANNER_MODE)
+
+/******************************************************************************
+ * TV Keys
+ ******************************************************************************/
+// TV
+KEY_MAP_ANDROID(TV, AKEYCODE_TV)
+
+// TV3DMode
+KEY_MAP_ANDROID(TV3DMode, AKEYCODE_3D_MODE)
+
+// TVAntennaCable
+KEY_MAP_ANDROID(TVAntennaCable, AKEYCODE_TV_ANTENNA_CABLE)
+
+// TVAudioDescription
+KEY_MAP_ANDROID(TVAudioDescription, AKEYCODE_TV_AUDIO_DESCRIPTION)
+
+// TVAudioDescriptionMixDown
+KEY_MAP_ANDROID(TVAudioDescriptionMixDown,
+                AKEYCODE_TV_AUDIO_DESCRIPTION_MIX_DOWN)
+
+// TVAudioDescriptionMixUp
+KEY_MAP_ANDROID(TVAudioDescriptionMixUp, AKEYCODE_TV_AUDIO_DESCRIPTION_MIX_UP)
+
+// TVContentsMenu
+KEY_MAP_ANDROID(TVContentsMenu, AKEYCODE_TV_CONTENTS_MENU)
+
+// TVDataService
+KEY_MAP_ANDROID(TVDataService, AKEYCODE_TV_DATA_SERVICE)
+
+// TVInput
+KEY_MAP_ANDROID(TVInput, AKEYCODE_TV_INPUT)
+
+// TVInputComponent1
+KEY_MAP_ANDROID(TVInputComponent1, AKEYCODE_TV_INPUT_COMPONENT_1)
+
+// TVInputComponent2
+KEY_MAP_ANDROID(TVInputComponent2, AKEYCODE_TV_INPUT_COMPONENT_2)
+
+// TVInputComposite1
+KEY_MAP_ANDROID(TVInputComposite1, AKEYCODE_TV_INPUT_COMPOSITE_1)
+
+// TVInputComposite2
+KEY_MAP_ANDROID(TVInputComposite2, AKEYCODE_TV_INPUT_COMPOSITE_2)
+
+// TVInputHDMI1
+KEY_MAP_ANDROID(TVInputHDMI1, AKEYCODE_TV_INPUT_HDMI_1)
+
+// TVInputHDMI2
+KEY_MAP_ANDROID(TVInputHDMI2, AKEYCODE_TV_INPUT_HDMI_2)
+
+// TVInputHDMI3
+KEY_MAP_ANDROID(TVInputHDMI3, AKEYCODE_TV_INPUT_HDMI_3)
+
+// TVInputHDMI4
+KEY_MAP_ANDROID(TVInputHDMI4, AKEYCODE_TV_INPUT_HDMI_4)
+
+// TVInputVGA1
+KEY_MAP_ANDROID(TVInputVGA1, AKEYCODE_TV_INPUT_VGA_1)
+
+// TVNetwork
+KEY_MAP_ANDROID(TVNetwork, AKEYCODE_TV_NETWORK)
+
+// TVNumberEntry
+KEY_MAP_ANDROID(TVNumberEntry, AKEYCODE_TV_NUMBER_ENTRY)
+
+// TVPower
+KEY_MAP_ANDROID(TVPower, AKEYCODE_TV_POWER)
+
+// TVRadioService
+KEY_MAP_ANDROID(TVRadioService, AKEYCODE_TV_RADIO_SERVICE)
+
+// TVSatellite
+KEY_MAP_ANDROID(TVSatellite, AKEYCODE_TV_SATELLITE)
+
+// TVSatelliteBS
+KEY_MAP_ANDROID(TVSatelliteBS, AKEYCODE_TV_SATELLITE_BS)
+
+// TVSatelliteCS
+KEY_MAP_ANDROID(TVSatelliteCS, AKEYCODE_TV_SATELLITE_CS)
+
+// TVSatelliteToggle
+KEY_MAP_ANDROID(TVSatelliteToggle, AKEYCODE_TV_SATELLITE_SERVICE)
+
+// TVTerrestrialAnalog
+KEY_MAP_ANDROID(TVTerrestrialAnalog, AKEYCODE_TV_TERRESTRIAL_ANALOG)
+
+// TVTerrestrialDigital
+KEY_MAP_ANDROID(TVTerrestrialDigital, AKEYCODE_TV_TERRESTRIAL_DIGITAL)
+
+// TVTimer
+KEY_MAP_ANDROID(TVTimer, AKEYCODE_TV_TIMER_PROGRAMMING)
+
+/******************************************************************************
+ * Media Controller Keys
+ ******************************************************************************/
+// AVRInput
+KEY_MAP_ANDROID(AVRInput, AKEYCODE_AVR_INPUT)
+
+// AVRPower
+KEY_MAP_ANDROID(AVRPower, AKEYCODE_AVR_POWER)
+
+// ColorF0Red
+KEY_MAP_GTK(ColorF0Red, GDK_Red)
+KEY_MAP_ANDROID(ColorF0Red, AKEYCODE_PROG_RED)
+
+// ColorF1Green
+KEY_MAP_GTK(ColorF1Green, GDK_Green)
+KEY_MAP_ANDROID(ColorF1Green, AKEYCODE_PROG_GREEN)
+
+// ColorF2Yellow
+KEY_MAP_GTK(ColorF2Yellow, GDK_Yellow)
+KEY_MAP_ANDROID(ColorF2Yellow, AKEYCODE_PROG_YELLOW)
+
+// ColorF3Blue
+KEY_MAP_GTK(ColorF3Blue, GDK_Blue)
+KEY_MAP_ANDROID(ColorF3Blue, AKEYCODE_PROG_BLUE)
+
+// ClosedCaptionToggle
+KEY_MAP_ANDROID(ClosedCaptionToggle, AKEYCODE_CAPTIONS)
+
+// Dimmer
+KEY_MAP_GTK(Dimmer, GDK_BrightnessAdjust)
+
+// DVR
+KEY_MAP_ANDROID(DVR, AKEYCODE_DVR)
+
+// Guide
+KEY_MAP_ANDROID(Guide, AKEYCODE_GUIDE)
+
+// Info
+KEY_MAP_ANDROID(Info, AKEYCODE_INFO)
+
+// MediaAudioTrack
+KEY_MAP_ANDROID(MediaAudioTrack, AKEYCODE_MEDIA_AUDIO_TRACK)
+
+// MediaLast
+KEY_MAP_ANDROID(MediaLast, AKEYCODE_LAST_CHANNEL)
+
+// MediaTopMenu
+KEY_MAP_ANDROID(MediaTopMenu, AKEYCODE_MEDIA_TOP_MENU)
+
+// MediaSkipBackward
+KEY_MAP_ANDROID(MediaSkipBackward, AKEYCODE_MEDIA_SKIP_BACKWARD)
+
+// MediaSkipForward
+KEY_MAP_ANDROID(MediaSkipForward, AKEYCODE_MEDIA_SKIP_FORWARD)
+
+// MediaStepBackward
+KEY_MAP_ANDROID(MediaStepBackward, AKEYCODE_MEDIA_STEP_BACKWARD)
+
+// MediaStepForward
+KEY_MAP_ANDROID(MediaStepForward, AKEYCODE_MEDIA_STEP_FORWARD)
+
+// NavigateIn
+KEY_MAP_ANDROID(NavigateIn, AKEYCODE_NAVIGATE_IN)
+
+// NavigateNext
+KEY_MAP_ANDROID(NavigateNext, AKEYCODE_NAVIGATE_NEXT)
+
+// NavigateOut
+KEY_MAP_ANDROID(NavigateOut, AKEYCODE_NAVIGATE_OUT)
+
+// NavigatePrevious
+KEY_MAP_ANDROID(NavigatePrevious, AKEYCODE_NAVIGATE_PREVIOUS)
+
+// Pairing
+KEY_MAP_ANDROID(Pairing, AKEYCODE_PAIRING)
+
+// PinPToggle
+KEY_MAP_ANDROID(PinPToggle, AKEYCODE_WINDOW)
+
+// RandomToggle
+KEY_MAP_GTK(RandomToggle, GDK_AudioRandomPlay)
+
+// Settings
+KEY_MAP_ANDROID(Settings, AKEYCODE_SETTINGS)
+
+// STBInput
+KEY_MAP_ANDROID(STBInput, AKEYCODE_STB_INPUT)
+
+// STBPower
+KEY_MAP_ANDROID(STBPower, AKEYCODE_STB_POWER)
+
+// Subtitle
+KEY_MAP_GTK(Subtitle, GDK_Subtitle)
+
+// Teletext
+KEY_MAP_ANDROID(Teletext, AKEYCODE_TV_TELETEXT)
+
+// VideoModeNext
+KEY_MAP_GTK(VideoModeNext, GDK_Next_VMode)
+
+// ZoomToggle
+KEY_MAP_WIN(ZoomToggle, VK_ZOOM)
+KEY_MAP_ANDROID(ZoomToggle, AKEYCODE_TV_ZOOM_MODE)
+
+/******************************************************************************
+ * Keys not defined by any standards
+ ******************************************************************************/
+// SoftLeft
+KEY_MAP_ANDROID(SoftLeft, AKEYCODE_SOFT_LEFT)
+
+// SoftRight
+KEY_MAP_ANDROID(SoftRight, AKEYCODE_SOFT_RIGHT)
+
+#undef KEY_MAP_WIN
+#undef KEY_MAP_WIN_JPN
+#undef KEY_MAP_WIN_KOR
+#undef KEY_MAP_WIN_OTH
+#undef KEY_MAP_WIN_CMD
+#undef KEY_MAP_COCOA
+#undef KEY_MAP_GTK
+#undef KEY_MAP_ANDROID
diff --git a/widget/NativeMenu.h b/widget/NativeMenu.h
new file mode 100644
index 0000000000..ef1808c7f9
--- /dev/null
+++ b/widget/NativeMenu.h
@@ -0,0 +1,101 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_NativeMenu_h
+#define mozilla_widget_NativeMenu_h
+
+#include "nsISupportsImpl.h"
+#include "Units.h"
+
+class nsIFrame;
+class nsPresContext;
+
+namespace mozilla {
+using Modifiers = uint16_t;
+class ErrorResult;
+}  // namespace mozilla
+
+namespace mozilla::dom {
+class Element;
+}
+
+namespace mozilla::widget {
+
+class NativeMenu {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(NativeMenu)
+
+  // Show this menu as a context menu at the specified position.
+  // This call assumes that the popupshowing event for the root popup has
+  // already been sent and "approved", i.e. preventDefault() was not called.
+  virtual void ShowAsContextMenu(nsIFrame* aClickedFrame,
+                                 const CSSIntPoint& aPosition,
+                                 bool aIsContextMenu) = 0;
+
+  // Close the menu and synchronously fire popuphiding / popuphidden events.
+  // Returns false if the menu wasn't open.
+  virtual bool Close() = 0;
+
+  // Activate aItemElement and close this menu.
+  // aItemElement can be nested arbitrarily deeply within submenus inside this
+  // menu. Only works while this menu (and any submenus on the path to the
+  // item) is open, otherwise aRv reports an error.
+  virtual void ActivateItem(dom::Element* aItemElement, Modifiers aModifiers,
+                            int16_t aButton, ErrorResult& aRv) = 0;
+
+  // Open, or simulate the opening of, a submenu.
+  // aMenuElement can be nested arbitrarily deeply within submenus inside this
+  // menu. Only works while this menu (and any submenus on the path to the
+  // submenu) is open.
+  virtual void OpenSubmenu(dom::Element* aMenuElement) = 0;
+
+  // Closing, or simulate the closing of, a submenu.
+  // aMenuElement can be nested arbitrarily deeply within submenus inside this
+  // menu. Only works while this menu (and any submenus on the path to the
+  // submenu) is open.
+  virtual void CloseSubmenu(dom::Element* aMenuElement) = 0;
+
+  // Return this NativeMenu's DOM element.
+  virtual RefPtr<dom::Element> Element() = 0;
+
+  class Observer {
+   public:
+    // Called when the menu opened, after popupshown.
+    // No strong reference is held to the observer during the call.
+    virtual void OnNativeMenuOpened() = 0;
+
+    // Called when the menu closed, after popuphidden.
+    // No strong reference is held to the observer during the call.
+    virtual void OnNativeMenuClosed() = 0;
+
+    // Called before the popupshowing event of a submenu fires.
+    virtual void OnNativeSubMenuWillOpen(dom::Element* aPopupElement) = 0;
+
+    // Called after the popupshown event of a submenu fired.
+    virtual void OnNativeSubMenuDidOpen(dom::Element* aPopupElement) = 0;
+
+    // Called after the popuphidden event of a submenu fired.
+    virtual void OnNativeSubMenuClosed(dom::Element* aPopupElement) = 0;
+
+    // Called before the command event of an activated menu item fires.
+    virtual void OnNativeMenuWillActivateItem(
+        dom::Element* aMenuItemElement) = 0;
+  };
+
+  // Add an observer that gets notified of menu opening and closing.
+  // The menu does not keep a strong reference the observer. The observer must
+  // remove itself before it is destroyed.
+  virtual void AddObserver(Observer* aObserver) = 0;
+
+  // Remove an observer that was previously added with AddObserver.
+  virtual void RemoveObserver(Observer* aObserver) = 0;
+
+ protected:
+  virtual ~NativeMenu() = default;
+};
+
+}  // namespace mozilla::widget
+
+#endif  // mozilla_widget_NativeMenu_h
diff --git a/widget/NativeMenuSupport.h b/widget/NativeMenuSupport.h
new file mode 100644
index 0000000000..c6429b5d4d
--- /dev/null
+++ b/widget/NativeMenuSupport.h
@@ -0,0 +1,47 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_NativeMenuSupport_h
+#define mozilla_widget_NativeMenuSupport_h
+
+#include "mozilla/RefPtr.h"
+
+class nsIWidget;
+
+#if defined(XP_MACOSX) || defined(MOZ_WIDGET_GTK)
+#  define HAS_NATIVE_MENU_SUPPORT 1
+#endif
+
+namespace mozilla {
+
+namespace dom {
+class Element;
+}
+
+namespace widget {
+
+class NativeMenu;
+
+class NativeMenuSupport final {
+ public:
+  // Given a top-level window widget and a menu bar DOM node, sets up native
+  // menus. Once created, native menus are controlled via the DOM, including
+  // destruction.
+  static void CreateNativeMenuBar(nsIWidget* aParent,
+                                  dom::Element* aMenuBarElement);
+
+  // Given a menupopup DOM node, create a NativeMenu instance that can be shown
+  // as a native context menu.
+  static already_AddRefed<NativeMenu> CreateNativeContextMenu(
+      dom::Element* aPopup);
+
+  // Whether or not native context menus are enabled.
+  static bool ShouldUseNativeContextMenus();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_NativeMenuSupport_h
diff --git a/widget/PClipboardReadRequest.ipdl b/widget/PClipboardReadRequest.ipdl
new file mode 100644
index 0000000000..39ae8ed38e
--- /dev/null
+++ b/widget/PClipboardReadRequest.ipdl
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PContent;
+
+include DOMTypes;
+include IPCTransferable;
+include NeckoChannelParams;
+
+using nsContentPolicyType from "nsIContentPolicy.h";
+
+namespace mozilla {
+
+protocol PClipboardReadRequest {
+  manager PContent;
+
+ parent:
+  async GetData(nsCString[] aFlavors) returns (IPCTransferableDataOrError aTransferableData);
+
+ both:
+  async __delete__();
+};
+
+} // namespace mozilla
diff --git a/widget/PClipboardWriteRequest.ipdl b/widget/PClipboardWriteRequest.ipdl
new file mode 100644
index 0000000000..54b7c9a136
--- /dev/null
+++ b/widget/PClipboardWriteRequest.ipdl
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PContent;
+
+include DOMTypes;
+include IPCTransferable;
+include NeckoChannelParams;
+
+using nsContentPolicyType from "nsIContentPolicy.h";
+
+namespace mozilla {
+
+protocol PClipboardWriteRequest {
+  manager PContent;
+
+ parent:
+  async SetData(IPCTransferable aTransferable);
+
+ both:
+  async __delete__(nsresult aResult);
+};
+
+} // namespace mozilla
diff --git a/widget/PrintBackgroundTask.h b/widget/PrintBackgroundTask.h
new file mode 100644
index 0000000000..8b18c8a879
--- /dev/null
+++ b/widget/PrintBackgroundTask.h
@@ -0,0 +1,121 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_PrintBackgroundTask_h_
+#define mozilla_PrintBackgroundTask_h_
+
+#include "mozilla/dom/Promise.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/Telemetry.h"
+
+#include <tuple>
+#include <utility>
+
+// A helper to resolve a DOM Promise with the result of a const method, executed
+// in another thread.
+//
+// Once in the main thread, the caller can turn the result of the method into a
+// JSValue by specializing ResolveOrReject.
+namespace mozilla {
+
+template <typename T, typename Result>
+void ResolveOrReject(dom::Promise& aPromise, T&, Result& aResult) {
+  aPromise.MaybeResolve(std::forward<Result>(aResult));
+}
+
+template <typename T, typename Result, typename... Args>
+using PrintBackgroundTask = Result (T::*)(Args...) const;
+
+template <typename T, typename Result, typename... Args>
+void SpawnPrintBackgroundTask(
+    T& aReceiver, dom::Promise& aPromise, const nsCString& aTelemetryKey,
+    PrintBackgroundTask<T, Result, Args...> aBackgroundTask, Args... aArgs) {
+  auto promiseHolder = MakeRefPtr<nsMainThreadPtrHolder<dom::Promise>>(
+      "nsPrinterBase::SpawnBackgroundTaskPromise", &aPromise);
+  // We actually want to allow to access the printer data from the callback, so
+  // disable strict checking. They should of course only access immutable
+  // members.
+  auto holder = MakeRefPtr<nsMainThreadPtrHolder<T>>(
+      "nsPrinterBase::SpawnBackgroundTaskPrinter", &aReceiver,
+      /* strict = */ false);
+  // See
+  // https://stackoverflow.com/questions/47496358/c-lambdas-how-to-capture-variadic-parameter-pack-from-the-upper-scope
+  // about the tuple shenanigans. It could be improved with C++20
+  NS_DispatchBackgroundTask(
+      NS_NewRunnableFunction(
+          "SpawnPrintBackgroundTask",
+          [holder = std::move(holder), promiseHolder = std::move(promiseHolder),
+           aTelemetryKey, startRoundTrip = TimeStamp::Now(),
+           backgroundTask = aBackgroundTask,
+           aArgs = std::make_tuple(std::forward<Args>(aArgs)...)] {
+            auto start = TimeStamp::Now();
+            Result result = std::apply(
+                [&](auto&&... args) {
+                  return (holder->get()->*backgroundTask)(args...);
+                },
+                std::move(aArgs));
+            Telemetry::AccumulateTimeDelta(
+                Telemetry::PRINT_BACKGROUND_TASK_TIME_MS, aTelemetryKey, start);
+            NS_DispatchToMainThread(NS_NewRunnableFunction(
+                "SpawnPrintBackgroundTaskResolution",
+                [holder = std::move(holder),
+                 promiseHolder = std::move(promiseHolder),
+                 telemetryKey = std::move(aTelemetryKey), startRoundTrip,
+                 result = std::move(result)] {
+                  Telemetry::AccumulateTimeDelta(
+                      Telemetry::PRINT_BACKGROUND_TASK_ROUND_TRIP_TIME_MS,
+                      telemetryKey, startRoundTrip);
+                  ResolveOrReject(*promiseHolder->get(), *holder->get(),
+                                  result);
+                }));
+          }),
+      NS_DISPATCH_EVENT_MAY_BLOCK);
+}
+
+// Gets a fresh promise into aResultPromise, that resolves whenever the print
+// background task finishes.
+template <typename T, typename Result, typename... Args>
+nsresult PrintBackgroundTaskPromise(
+    T& aReceiver, JSContext* aCx, dom::Promise** aResultPromise,
+    const nsCString& aTelemetryKey,
+    PrintBackgroundTask<T, Result, Args...> aTask, Args... aArgs) {
+  ErrorResult rv;
+  RefPtr<dom::Promise> promise =
+      dom::Promise::Create(xpc::CurrentNativeGlobal(aCx), rv);
+  if (MOZ_UNLIKELY(rv.Failed())) {
+    return rv.StealNSResult();
+  }
+
+  SpawnPrintBackgroundTask(aReceiver, *promise, aTelemetryKey, aTask,
+                           std::forward<Args>(aArgs)...);
+
+  promise.forget(aResultPromise);
+  return NS_OK;
+}
+
+// Resolves an async attribute via a background task, creating and storing a
+// promise as needed in aPromiseSlot.
+template <typename T, typename Result, typename... Args>
+nsresult AsyncPromiseAttributeGetter(
+    T& aReceiver, RefPtr<dom::Promise>& aPromiseSlot, JSContext* aCx,
+    dom::Promise** aResultPromise, const nsCString& aTelemetryKey,
+    PrintBackgroundTask<T, Result, Args...> aTask, Args... aArgs) {
+  if (RefPtr<dom::Promise> existing = aPromiseSlot) {
+    existing.forget(aResultPromise);
+    return NS_OK;
+  }
+
+  nsresult rv =
+      PrintBackgroundTaskPromise(aReceiver, aCx, aResultPromise, aTelemetryKey,
+                                 aTask, std::forward<Args>(aArgs)...);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  aPromiseSlot = *aResultPromise;
+  return NS_OK;
+}
+
+}  // namespace mozilla
+
+#endif
diff --git a/widget/PuppetBidiKeyboard.cpp b/widget/PuppetBidiKeyboard.cpp
new file mode 100644
index 0000000000..99ea6f6ca9
--- /dev/null
+++ b/widget/PuppetBidiKeyboard.cpp
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "PuppetBidiKeyboard.h"
+#include "nsIWidget.h"
+
+using namespace mozilla::widget;
+
+NS_IMPL_ISUPPORTS(PuppetBidiKeyboard, nsIBidiKeyboard)
+
+PuppetBidiKeyboard::PuppetBidiKeyboard()
+    : nsIBidiKeyboard(), mIsLangRTL(false), mHaveBidiKeyboards(false) {}
+
+PuppetBidiKeyboard::~PuppetBidiKeyboard() = default;
+
+NS_IMETHODIMP
+PuppetBidiKeyboard::Reset() { return NS_OK; }
+
+NS_IMETHODIMP
+PuppetBidiKeyboard::IsLangRTL(bool* aIsRTL) {
+  *aIsRTL = mIsLangRTL;
+  return NS_OK;
+}
+
+void PuppetBidiKeyboard::SetBidiKeyboardInfo(bool aIsLangRTL,
+                                             bool aHaveBidiKeyboards) {
+  mIsLangRTL = aIsLangRTL;
+  mHaveBidiKeyboards = aHaveBidiKeyboards;
+}
+
+NS_IMETHODIMP
+PuppetBidiKeyboard::GetHaveBidiKeyboards(bool* aResult) {
+  *aResult = mHaveBidiKeyboards;
+  return NS_OK;
+}
+
+// static
+already_AddRefed<nsIBidiKeyboard>
+nsIWidget::CreateBidiKeyboardContentProcess() {
+  return do_AddRef(new PuppetBidiKeyboard());
+}
diff --git a/widget/PuppetBidiKeyboard.h b/widget/PuppetBidiKeyboard.h
new file mode 100644
index 0000000000..82250cc36e
--- /dev/null
+++ b/widget/PuppetBidiKeyboard.h
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_PuppetBidiKeyboard_h_
+#define mozilla_widget_PuppetBidiKeyboard_h_
+
+#include "nsIBidiKeyboard.h"
+
+namespace mozilla {
+namespace widget {
+
+class PuppetBidiKeyboard final : public nsIBidiKeyboard {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIBIDIKEYBOARD
+
+  PuppetBidiKeyboard();
+
+  void SetBidiKeyboardInfo(bool aIsLangRTL, bool aHaveBidiKeyboards);
+
+ private:
+  ~PuppetBidiKeyboard();
+
+  bool mIsLangRTL;
+  bool mHaveBidiKeyboards;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_PuppetBidiKeyboard_h_
diff --git a/widget/PuppetWidget.cpp b/widget/PuppetWidget.cpp
new file mode 100644
index 0000000000..07b22d9a2b
--- /dev/null
+++ b/widget/PuppetWidget.cpp
@@ -0,0 +1,1179 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "base/basictypes.h"
+
+#include "gfxPlatform.h"
+#include "nsRefreshDriver.h"
+#include "mozilla/dom/BrowserChild.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/IMEStateManager.h"
+#include "mozilla/layers/APZChild.h"
+#include "mozilla/layers/WebRenderLayerManager.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/SchedulerGroup.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/StaticPrefs_gfx.h"
+#include "mozilla/TextComposition.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/Unused.h"
+#include "PuppetWidget.h"
+#include "nsContentUtils.h"
+#include "nsIWidgetListener.h"
+#include "imgIContainer.h"
+#include "nsView.h"
+#include "nsXPLookAndFeel.h"
+#include "nsPrintfCString.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::gfx;
+using namespace mozilla::layers;
+using namespace mozilla::widget;
+
+static void InvalidateRegion(nsIWidget* aWidget,
+                             const LayoutDeviceIntRegion& aRegion) {
+  for (auto iter = aRegion.RectIter(); !iter.Done(); iter.Next()) {
+    aWidget->Invalidate(iter.Get());
+  }
+}
+
+/*static*/
+already_AddRefed<nsIWidget> nsIWidget::CreatePuppetWidget(
+    BrowserChild* aBrowserChild) {
+  MOZ_ASSERT(!aBrowserChild || nsIWidget::UsePuppetWidgets(),
+             "PuppetWidgets not allowed in this configuration");
+
+  nsCOMPtr<nsIWidget> widget = new PuppetWidget(aBrowserChild);
+  return widget.forget();
+}
+
+namespace mozilla {
+namespace widget {
+
+static bool IsPopup(const widget::InitData* aInitData) {
+  return aInitData && aInitData->mWindowType == WindowType::Popup;
+}
+
+static bool MightNeedIMEFocus(const widget::InitData* aInitData) {
+  // In the puppet-widget world, popup widgets are just dummies and
+  // shouldn't try to mess with IME state.
+#ifdef MOZ_CROSS_PROCESS_IME
+  return !IsPopup(aInitData);
+#else
+  return false;
+#endif
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(PuppetWidget, nsBaseWidget,
+                            TextEventDispatcherListener)
+
+PuppetWidget::PuppetWidget(BrowserChild* aBrowserChild)
+    : mBrowserChild(aBrowserChild),
+      mMemoryPressureObserver(nullptr),
+      mEnabled(false),
+      mVisible(false),
+      mSizeMode(nsSizeMode_Normal),
+      mNeedIMEStateInit(false),
+      mIgnoreCompositionEvents(false) {
+  // Setting 'Unknown' means "not yet cached".
+  mInputContext.mIMEState.mEnabled = IMEEnabled::Unknown;
+}
+
+PuppetWidget::~PuppetWidget() { Destroy(); }
+
+void PuppetWidget::InfallibleCreate(nsIWidget* aParent,
+                                    nsNativeWidget aNativeParent,
+                                    const LayoutDeviceIntRect& aRect,
+                                    widget::InitData* aInitData) {
+  MOZ_ASSERT(!aNativeParent, "got a non-Puppet native parent");
+
+  BaseCreate(nullptr, aInitData);
+
+  mBounds = aRect;
+  mEnabled = true;
+  mVisible = true;
+
+  mDrawTarget = gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(
+      IntSize(1, 1), SurfaceFormat::B8G8R8A8);
+
+  mNeedIMEStateInit = MightNeedIMEFocus(aInitData);
+
+  PuppetWidget* parent = static_cast<PuppetWidget*>(aParent);
+  if (parent) {
+    parent->SetChild(this);
+    mWindowRenderer = parent->GetWindowRenderer();
+  } else {
+    Resize(mBounds.X(), mBounds.Y(), mBounds.Width(), mBounds.Height(), false);
+  }
+  mMemoryPressureObserver = MemoryPressureObserver::Create(this);
+}
+
+nsresult PuppetWidget::Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                              const LayoutDeviceIntRect& aRect,
+                              widget::InitData* aInitData) {
+  InfallibleCreate(aParent, aNativeParent, aRect, aInitData);
+  return NS_OK;
+}
+
+void PuppetWidget::InitIMEState() {
+  MOZ_ASSERT(mBrowserChild);
+  if (mNeedIMEStateInit) {
+    mContentCache.Clear();
+    mBrowserChild->SendUpdateContentCache(mContentCache);
+    mIMENotificationRequestsOfParent = IMENotificationRequests();
+    mNeedIMEStateInit = false;
+  }
+}
+
+already_AddRefed<nsIWidget> PuppetWidget::CreateChild(
+    const LayoutDeviceIntRect& aRect, widget::InitData* aInitData,
+    bool aForceUseIWidgetParent) {
+  bool isPopup = IsPopup(aInitData);
+  nsCOMPtr<nsIWidget> widget = nsIWidget::CreatePuppetWidget(mBrowserChild);
+  return ((widget && NS_SUCCEEDED(widget->Create(isPopup ? nullptr : this,
+                                                 nullptr, aRect, aInitData)))
+              ? widget.forget()
+              : nullptr);
+}
+
+void PuppetWidget::Destroy() {
+  if (mOnDestroyCalled) {
+    return;
+  }
+  mOnDestroyCalled = true;
+
+  Base::OnDestroy();
+  Base::Destroy();
+  if (mMemoryPressureObserver) {
+    mMemoryPressureObserver->Unregister();
+    mMemoryPressureObserver = nullptr;
+  }
+  mChild = nullptr;
+  if (mWindowRenderer) {
+    mWindowRenderer->Destroy();
+  }
+  mWindowRenderer = nullptr;
+  mBrowserChild = nullptr;
+}
+
+void PuppetWidget::Show(bool aState) {
+  NS_ASSERTION(mEnabled,
+               "does it make sense to Show()/Hide() a disabled widget?");
+
+  bool wasVisible = mVisible;
+  mVisible = aState;
+
+  if (mChild) {
+    mChild->mVisible = aState;
+  }
+
+  if (!wasVisible && mVisible) {
+    // The previously attached widget listener is handy if
+    // we're transitioning from page to page without dropping
+    // layers (since we'll continue to show the old layers
+    // associated with that old widget listener). If the
+    // PuppetWidget was hidden, those layers are dropped,
+    // so the previously attached widget listener is really
+    // of no use anymore (and is actually actively harmful - see
+    // bug 1323586).
+    mPreviouslyAttachedWidgetListener = nullptr;
+    Resize(mBounds.Width(), mBounds.Height(), false);
+    Invalidate(mBounds);
+  }
+}
+
+void PuppetWidget::Resize(double aWidth, double aHeight, bool aRepaint) {
+  LayoutDeviceIntRect oldBounds = mBounds;
+  mBounds.SizeTo(
+      LayoutDeviceIntSize(NSToIntRound(aWidth), NSToIntRound(aHeight)));
+
+  if (mChild) {
+    mChild->Resize(aWidth, aHeight, aRepaint);
+    return;
+  }
+
+  // XXX: roc says that |aRepaint| dictates whether or not to
+  // invalidate the expanded area
+  if (oldBounds.Size() < mBounds.Size() && aRepaint) {
+    LayoutDeviceIntRegion dirty(mBounds);
+    dirty.Sub(dirty, oldBounds);
+    InvalidateRegion(this, dirty);
+  }
+
+  // call WindowResized() on both the current listener, and possibly
+  // also the previous one if we're in a state where we're drawing that one
+  // because the current one is paint suppressed
+  if (!oldBounds.IsEqualEdges(mBounds) && mAttachedWidgetListener) {
+    if (GetCurrentWidgetListener() &&
+        GetCurrentWidgetListener() != mAttachedWidgetListener) {
+      GetCurrentWidgetListener()->WindowResized(this, mBounds.Width(),
+                                                mBounds.Height());
+    }
+    mAttachedWidgetListener->WindowResized(this, mBounds.Width(),
+                                           mBounds.Height());
+  }
+}
+
+void PuppetWidget::SetFocus(Raise aRaise, CallerType aCallerType) {
+  if (aRaise == Raise::Yes && mBrowserChild) {
+    mBrowserChild->SendRequestFocus(true, aCallerType);
+  }
+}
+
+void PuppetWidget::Invalidate(const LayoutDeviceIntRect& aRect) {
+#ifdef DEBUG
+  debug_DumpInvalidate(stderr, this, &aRect, "PuppetWidget", 0);
+#endif
+
+  if (mChild) {
+    mChild->Invalidate(aRect);
+    return;
+  }
+
+  if (mBrowserChild && !aRect.IsEmpty() && !mWidgetPaintTask.IsPending()) {
+    mWidgetPaintTask = new WidgetPaintTask(this);
+    nsCOMPtr<nsIRunnable> event(mWidgetPaintTask.get());
+    SchedulerGroup::Dispatch(event.forget());
+  }
+}
+
+mozilla::LayoutDeviceToLayoutDeviceMatrix4x4
+PuppetWidget::WidgetToTopLevelWidgetTransform() {
+  if (!GetOwningBrowserChild()) {
+    NS_WARNING("PuppetWidget without Tab does not have transform information.");
+    return mozilla::LayoutDeviceToLayoutDeviceMatrix4x4();
+  }
+  return GetOwningBrowserChild()->GetChildToParentConversionMatrix();
+}
+
+void PuppetWidget::InitEvent(WidgetGUIEvent& aEvent,
+                             LayoutDeviceIntPoint* aPoint) {
+  if (nullptr == aPoint) {
+    aEvent.mRefPoint = LayoutDeviceIntPoint(0, 0);
+  } else {
+    // use the point override if provided
+    aEvent.mRefPoint = *aPoint;
+  }
+}
+
+nsresult PuppetWidget::DispatchEvent(WidgetGUIEvent* aEvent,
+                                     nsEventStatus& aStatus) {
+#ifdef DEBUG
+  debug_DumpEvent(stdout, aEvent->mWidget, aEvent, "PuppetWidget", 0);
+#endif
+
+  MOZ_ASSERT(!mChild || mChild->mWindowType == WindowType::Popup,
+             "Unexpected event dispatch!");
+
+  MOZ_ASSERT(!aEvent->AsKeyboardEvent() ||
+                 aEvent->mFlags.mIsSynthesizedForTests ||
+                 aEvent->AsKeyboardEvent()->AreAllEditCommandsInitialized(),
+             "Non-sysnthesized keyboard events should have edit commands for "
+             "all types "
+             "before dispatched");
+
+  if (aEvent->mClass == eCompositionEventClass) {
+    // If we've already requested to commit/cancel the latest composition,
+    // TextComposition for the old composition has been destroyed.  Then,
+    // the DOM tree needs to listen to next eCompositionStart and its
+    // following events.  So, until we meet new eCompositionStart, let's
+    // discard all unnecessary composition events here.
+    if (mIgnoreCompositionEvents) {
+      if (aEvent->mMessage != eCompositionStart) {
+        aStatus = nsEventStatus_eIgnore;
+        return NS_OK;
+      }
+      // Now, we receive new eCompositionStart.  Let's restart to handle
+      // composition in this process.
+      mIgnoreCompositionEvents = false;
+    }
+    // Store the latest native IME context of parent process's widget or
+    // TextEventDispatcher if it's in this process.
+    WidgetCompositionEvent* compositionEvent = aEvent->AsCompositionEvent();
+#ifdef DEBUG
+    if (mNativeIMEContext.IsValid() &&
+        mNativeIMEContext != compositionEvent->mNativeIMEContext) {
+      RefPtr<TextComposition> composition =
+          IMEStateManager::GetTextCompositionFor(this);
+      MOZ_ASSERT(
+          !composition,
+          "When there is composition caused by old native IME context, "
+          "composition events caused by different native IME context are not "
+          "allowed");
+    }
+#endif  // #ifdef DEBUG
+    mNativeIMEContext = compositionEvent->mNativeIMEContext;
+    mContentCache.OnCompositionEvent(*compositionEvent);
+  }
+
+  // If the event is a composition event or a keyboard event, it should be
+  // dispatched with TextEventDispatcher if we could do that with current
+  // design.  However, we cannot do that without big changes and the behavior
+  // is not so complicated for now.  Therefore, we should just notify it
+  // of dispatching events and TextEventDispatcher should emulate the state
+  // with events here.
+  if (aEvent->mClass == eCompositionEventClass ||
+      aEvent->mClass == eKeyboardEventClass) {
+    TextEventDispatcher* dispatcher = GetTextEventDispatcher();
+    // However, if the event is being dispatched by the text event dispatcher
+    // or, there is native text event dispatcher listener, that means that
+    // native text input event handler is in this process like on Android,
+    // and the event is not synthesized for tests, the event is coming from
+    // the TextEventDispatcher.  In these cases, we shouldn't notify
+    // TextEventDispatcher of dispatching the event.
+    if (!dispatcher->IsDispatchingEvent() &&
+        !(mNativeTextEventDispatcherListener &&
+          !aEvent->mFlags.mIsSynthesizedForTests)) {
+      DebugOnly<nsresult> rv =
+          dispatcher->BeginInputTransactionFor(aEvent, this);
+      NS_WARNING_ASSERTION(
+          NS_SUCCEEDED(rv),
+          "The text event dispatcher should always succeed to start input "
+          "transaction for the event");
+    }
+  }
+
+  aStatus = nsEventStatus_eIgnore;
+
+  if (GetCurrentWidgetListener()) {
+    aStatus =
+        GetCurrentWidgetListener()->HandleEvent(aEvent, mUseAttachedEvents);
+  }
+
+  return NS_OK;
+}
+
+nsIWidget::ContentAndAPZEventStatus PuppetWidget::DispatchInputEvent(
+    WidgetInputEvent* aEvent) {
+  ContentAndAPZEventStatus status;
+  if (!AsyncPanZoomEnabled()) {
+    DispatchEvent(aEvent, status.mContentStatus);
+    return status;
+  }
+
+  if (!mBrowserChild) {
+    return status;
+  }
+
+  switch (aEvent->mClass) {
+    case eWheelEventClass:
+      Unused << mBrowserChild->SendDispatchWheelEvent(*aEvent->AsWheelEvent());
+      break;
+    case eMouseEventClass:
+      Unused << mBrowserChild->SendDispatchMouseEvent(*aEvent->AsMouseEvent());
+      break;
+    case eKeyboardEventClass:
+      Unused << mBrowserChild->SendDispatchKeyboardEvent(
+          *aEvent->AsKeyboardEvent());
+      break;
+    case eTouchEventClass:
+      Unused << mBrowserChild->SendDispatchTouchEvent(*aEvent->AsTouchEvent());
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE("unsupported event type");
+  }
+
+  return status;
+}
+
+nsresult PuppetWidget::SynthesizeNativeKeyEvent(
+    int32_t aNativeKeyboardLayout, int32_t aNativeKeyCode,
+    uint32_t aModifierFlags, const nsAString& aCharacters,
+    const nsAString& aUnmodifiedCharacters, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "keyevent");
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendSynthesizeNativeKeyEvent(
+      aNativeKeyboardLayout, aNativeKeyCode, aModifierFlags, aCharacters,
+      aUnmodifiedCharacters, notifier.SaveObserver());
+  return NS_OK;
+}
+
+nsresult PuppetWidget::SynthesizeNativeMouseEvent(
+    mozilla::LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+    MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+    nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "mouseevent");
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendSynthesizeNativeMouseEvent(
+      aPoint, static_cast<uint32_t>(aNativeMessage),
+      static_cast<int16_t>(aButton), static_cast<uint32_t>(aModifierFlags),
+      notifier.SaveObserver());
+  return NS_OK;
+}
+
+nsresult PuppetWidget::SynthesizeNativeMouseMove(
+    mozilla::LayoutDeviceIntPoint aPoint, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "mousemove");
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendSynthesizeNativeMouseMove(aPoint, notifier.SaveObserver());
+  return NS_OK;
+}
+
+nsresult PuppetWidget::SynthesizeNativeMouseScrollEvent(
+    mozilla::LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage,
+    double aDeltaX, double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+    uint32_t aAdditionalFlags, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "mousescrollevent");
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendSynthesizeNativeMouseScrollEvent(
+      aPoint, aNativeMessage, aDeltaX, aDeltaY, aDeltaZ, aModifierFlags,
+      aAdditionalFlags, notifier.SaveObserver());
+  return NS_OK;
+}
+
+nsresult PuppetWidget::SynthesizeNativeTouchPoint(
+    uint32_t aPointerId, TouchPointerState aPointerState,
+    LayoutDeviceIntPoint aPoint, double aPointerPressure,
+    uint32_t aPointerOrientation, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchpoint");
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendSynthesizeNativeTouchPoint(
+      aPointerId, aPointerState, aPoint, aPointerPressure, aPointerOrientation,
+      notifier.SaveObserver());
+  return NS_OK;
+}
+
+nsresult PuppetWidget::SynthesizeNativeTouchPadPinch(
+    TouchpadGesturePhase aEventPhase, float aScale, LayoutDeviceIntPoint aPoint,
+    int32_t aModifierFlags) {
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendSynthesizeNativeTouchPadPinch(aEventPhase, aScale, aPoint,
+                                                   aModifierFlags);
+  return NS_OK;
+}
+
+nsresult PuppetWidget::SynthesizeNativeTouchTap(LayoutDeviceIntPoint aPoint,
+                                                bool aLongTap,
+                                                nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchtap");
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendSynthesizeNativeTouchTap(aPoint, aLongTap,
+                                              notifier.SaveObserver());
+  return NS_OK;
+}
+
+nsresult PuppetWidget::ClearNativeTouchSequence(nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "cleartouch");
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendClearNativeTouchSequence(notifier.SaveObserver());
+  return NS_OK;
+}
+
+nsresult PuppetWidget::SynthesizeNativePenInput(
+    uint32_t aPointerId, TouchPointerState aPointerState,
+    LayoutDeviceIntPoint aPoint, double aPressure, uint32_t aRotation,
+    int32_t aTiltX, int32_t aTiltY, int32_t aButton, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "peninput");
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendSynthesizeNativePenInput(
+      aPointerId, aPointerState, aPoint, aPressure, aRotation, aTiltX, aTiltY,
+      aButton, notifier.SaveObserver());
+  return NS_OK;
+}
+
+nsresult PuppetWidget::SynthesizeNativeTouchpadDoubleTap(
+    LayoutDeviceIntPoint aPoint, uint32_t aModifierFlags) {
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendSynthesizeNativeTouchpadDoubleTap(aPoint, aModifierFlags);
+  return NS_OK;
+}
+
+nsresult PuppetWidget::SynthesizeNativeTouchpadPan(
+    TouchpadGesturePhase aEventPhase, LayoutDeviceIntPoint aPoint,
+    double aDeltaX, double aDeltaY, int32_t aModifierFlags,
+    nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchpadpanevent");
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendSynthesizeNativeTouchpadPan(aEventPhase, aPoint, aDeltaX,
+                                                 aDeltaY, aModifierFlags,
+                                                 notifier.SaveObserver());
+  return NS_OK;
+}
+
+void PuppetWidget::LockNativePointer() {
+  if (!mBrowserChild) {
+    return;
+  }
+  mBrowserChild->SendLockNativePointer();
+}
+
+void PuppetWidget::UnlockNativePointer() {
+  if (!mBrowserChild) {
+    return;
+  }
+  mBrowserChild->SendUnlockNativePointer();
+}
+
+void PuppetWidget::SetConfirmedTargetAPZC(
+    uint64_t aInputBlockId,
+    const nsTArray<ScrollableLayerGuid>& aTargets) const {
+  if (mBrowserChild) {
+    mBrowserChild->SetTargetAPZC(aInputBlockId, aTargets);
+  }
+}
+
+void PuppetWidget::UpdateZoomConstraints(
+    const uint32_t& aPresShellId, const ScrollableLayerGuid::ViewID& aViewId,
+    const Maybe<ZoomConstraints>& aConstraints) {
+  if (mBrowserChild) {
+    mBrowserChild->DoUpdateZoomConstraints(aPresShellId, aViewId, aConstraints);
+  }
+}
+
+bool PuppetWidget::AsyncPanZoomEnabled() const {
+  return mBrowserChild && mBrowserChild->AsyncPanZoomEnabled();
+}
+
+bool PuppetWidget::GetEditCommands(NativeKeyBindingsType aType,
+                                   const WidgetKeyboardEvent& aEvent,
+                                   nsTArray<CommandInt>& aCommands) {
+  MOZ_ASSERT(!aEvent.mFlags.mIsSynthesizedForTests);
+  // Validate the arguments.
+  if (NS_WARN_IF(!nsIWidget::GetEditCommands(aType, aEvent, aCommands))) {
+    return false;
+  }
+  if (NS_WARN_IF(!mBrowserChild)) {
+    return false;
+  }
+  mBrowserChild->RequestEditCommands(aType, aEvent, aCommands);
+  return true;
+}
+
+WindowRenderer* PuppetWidget::GetWindowRenderer() {
+  if (!mWindowRenderer) {
+    if (XRE_IsParentProcess()) {
+      // On the parent process there is no CompositorBridgeChild which confuses
+      // some layers code, so we use basic layers instead. Note that we create
+      mWindowRenderer = new FallbackRenderer;
+      return mWindowRenderer;
+    }
+
+    // If we know for sure that the parent side of this BrowserChild is not
+    // connected to the compositor, we don't want to use a "remote" layer
+    // manager like WebRender or Client. Instead we use a Basic one which
+    // can do drawing in this process.
+    MOZ_ASSERT(!mBrowserChild ||
+               mBrowserChild->IsLayersConnected() != Some(true));
+    mWindowRenderer = CreateFallbackRenderer();
+  }
+
+  return mWindowRenderer;
+}
+
+bool PuppetWidget::CreateRemoteLayerManager(
+    const std::function<bool(WebRenderLayerManager*)>& aInitializeFunc) {
+  RefPtr<WebRenderLayerManager> lm = new WebRenderLayerManager(this);
+  MOZ_ASSERT(mBrowserChild);
+
+  if (!aInitializeFunc(lm)) {
+    return false;
+  }
+
+  // Force the old LM to self destruct, otherwise if the reference dangles we
+  // could fail to revoke the most recent transaction. We only want to replace
+  // it if we successfully create its successor because a partially initialized
+  // layer manager is worse than a fully initialized but shutdown layer manager.
+  DestroyLayerManager();
+  mWindowRenderer = std::move(lm);
+  return true;
+}
+
+nsresult PuppetWidget::RequestIMEToCommitComposition(bool aCancel) {
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+
+  MOZ_ASSERT(!Destroyed());
+
+  // There must not be composition which is caused by the PuppetWidget instance.
+  if (NS_WARN_IF(!mNativeIMEContext.IsValid())) {
+    return NS_OK;
+  }
+
+  // We've already requested to commit/cancel composition.
+  if (NS_WARN_IF(mIgnoreCompositionEvents)) {
+#ifdef DEBUG
+    RefPtr<TextComposition> composition =
+        IMEStateManager::GetTextCompositionFor(this);
+    MOZ_ASSERT(!composition);
+#endif  // #ifdef DEBUG
+    return NS_OK;
+  }
+
+  RefPtr<TextComposition> composition =
+      IMEStateManager::GetTextCompositionFor(this);
+  // This method shouldn't be called when there is no text composition instance.
+  if (NS_WARN_IF(!composition)) {
+    return NS_OK;
+  }
+
+  MOZ_DIAGNOSTIC_ASSERT(
+      composition->IsRequestingCommitOrCancelComposition(),
+      "Requesting commit or cancel composition should be requested via "
+      "TextComposition instance");
+
+  bool isCommitted = false;
+  nsAutoString committedString;
+  if (NS_WARN_IF(!mBrowserChild->SendRequestIMEToCommitComposition(
+          aCancel, composition->Id(), &isCommitted, &committedString))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // If the composition wasn't committed synchronously, we need to wait async
+  // composition events for destroying the TextComposition instance.
+  if (!isCommitted) {
+    return NS_OK;
+  }
+
+  // Dispatch eCompositionCommit event.
+  WidgetCompositionEvent compositionCommitEvent(true, eCompositionCommit, this);
+  InitEvent(compositionCommitEvent, nullptr);
+  compositionCommitEvent.mData = committedString;
+  nsEventStatus status = nsEventStatus_eIgnore;
+  DispatchEvent(&compositionCommitEvent, status);
+
+#ifdef DEBUG
+  RefPtr<TextComposition> currentComposition =
+      IMEStateManager::GetTextCompositionFor(this);
+  MOZ_ASSERT(!currentComposition);
+#endif  // #ifdef DEBUG
+
+  // Ignore the following composition events until we receive new
+  // eCompositionStart event.
+  mIgnoreCompositionEvents = true;
+
+  Unused << mBrowserChild->SendOnEventNeedingAckHandled(
+      eCompositionCommitRequestHandled, composition->Id());
+
+  // NOTE: PuppetWidget might be destroyed already.
+  return NS_OK;
+}
+
+// When this widget caches input context and currently managed by
+// IMEStateManager, the cache is valid.
+bool PuppetWidget::HaveValidInputContextCache() const {
+  return (mInputContext.mIMEState.mEnabled != IMEEnabled::Unknown &&
+          IMEStateManager::GetWidgetForActiveInputContext() == this);
+}
+
+nsRefreshDriver* PuppetWidget::GetTopLevelRefreshDriver() const {
+  if (!mBrowserChild) {
+    return nullptr;
+  }
+
+  if (PresShell* presShell = mBrowserChild->GetTopLevelPresShell()) {
+    return presShell->GetRefreshDriver();
+  }
+
+  return nullptr;
+}
+
+void PuppetWidget::SetInputContext(const InputContext& aContext,
+                                   const InputContextAction& aAction) {
+  mInputContext = aContext;
+  // Any widget instances cannot cache IME open state because IME open state
+  // can be changed by user but native IME may not notify us of changing the
+  // open state on some platforms.
+  mInputContext.mIMEState.mOpen = IMEState::OPEN_STATE_NOT_SUPPORTED;
+  if (!mBrowserChild) {
+    return;
+  }
+  mBrowserChild->SendSetInputContext(aContext, aAction);
+}
+
+InputContext PuppetWidget::GetInputContext() {
+  // XXX Currently, we don't support retrieving IME open state from child
+  //     process.
+
+  // If the cache of input context is valid, we can avoid to use synchronous
+  // IPC.
+  if (HaveValidInputContextCache()) {
+    return mInputContext;
+  }
+
+  NS_WARNING("PuppetWidget::GetInputContext() needs to retrieve it with IPC");
+
+  // Don't cache InputContext here because this process isn't managing IME
+  // state of the chrome widget.  So, we cannot modify mInputContext when
+  // chrome widget is set to new context.
+  InputContext context;
+  if (mBrowserChild) {
+    mBrowserChild->SendGetInputContext(&context.mIMEState);
+  }
+  return context;
+}
+
+NativeIMEContext PuppetWidget::GetNativeIMEContext() {
+  return mNativeIMEContext;
+}
+
+nsresult PuppetWidget::NotifyIMEOfFocusChange(
+    const IMENotification& aIMENotification) {
+  MOZ_ASSERT(IMEStateManager::CanSendNotificationToWidget());
+
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+
+  bool gotFocus = aIMENotification.mMessage == NOTIFY_IME_OF_FOCUS;
+  if (gotFocus) {
+    // When IME gets focus, we should initialize all information of the
+    // content, however, it may fail to get it because the editor may have
+    // already been blurred.
+    if (NS_WARN_IF(!mContentCache.CacheAll(this, &aIMENotification))) {
+      return NS_ERROR_FAILURE;
+    }
+  } else {
+    // When IME loses focus, we don't need to store anything.
+    mContentCache.Clear();
+  }
+
+  mIMENotificationRequestsOfParent =
+      IMENotificationRequests(IMENotificationRequests::NOTIFY_ALL);
+  RefPtr<PuppetWidget> self = this;
+  mBrowserChild->SendNotifyIMEFocus(mContentCache, aIMENotification)
+      ->Then(
+          GetMainThreadSerialEventTarget(), __func__,
+          [self](IMENotificationRequests&& aRequests) {
+            self->mIMENotificationRequestsOfParent = aRequests;
+            if (TextEventDispatcher* dispatcher =
+                    self->GetTextEventDispatcher()) {
+              dispatcher->OnWidgetChangeIMENotificationRequests(self);
+            }
+          },
+          [self](mozilla::ipc::ResponseRejectReason&& aReason) {
+            NS_WARNING("SendNotifyIMEFocus got rejected.");
+          });
+
+  return NS_OK;
+}
+
+nsresult PuppetWidget::NotifyIMEOfCompositionUpdate(
+    const IMENotification& aIMENotification) {
+  MOZ_ASSERT(IMEStateManager::CanSendNotificationToWidget());
+
+  if (NS_WARN_IF(!mBrowserChild)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (NS_WARN_IF(
+          !mContentCache.CacheCaretAndTextRects(this, &aIMENotification))) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendNotifyIMECompositionUpdate(mContentCache,
+                                                aIMENotification);
+  return NS_OK;
+}
+
+nsresult PuppetWidget::NotifyIMEOfTextChange(
+    const IMENotification& aIMENotification) {
+  MOZ_ASSERT(IMEStateManager::CanSendNotificationToWidget());
+  MOZ_ASSERT(aIMENotification.mMessage == NOTIFY_IME_OF_TEXT_CHANGE,
+             "Passed wrong notification");
+
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // FYI: text change notification is the first notification after
+  //      a user operation changes the content.  So, we need to modify
+  //      the cache as far as possible here.
+
+  if (NS_WARN_IF(!mContentCache.CacheText(this, &aIMENotification))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // BrowserParent doesn't this this to cache.  we don't send the notification
+  // if parent process doesn't request NOTIFY_TEXT_CHANGE.
+  if (mIMENotificationRequestsOfParent.WantTextChange()) {
+    mBrowserChild->SendNotifyIMETextChange(mContentCache, aIMENotification);
+  } else {
+    mBrowserChild->SendUpdateContentCache(mContentCache);
+  }
+  return NS_OK;
+}
+
+nsresult PuppetWidget::NotifyIMEOfSelectionChange(
+    const IMENotification& aIMENotification) {
+  MOZ_ASSERT(IMEStateManager::CanSendNotificationToWidget());
+  MOZ_ASSERT(aIMENotification.mMessage == NOTIFY_IME_OF_SELECTION_CHANGE,
+             "Passed wrong notification");
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Note that selection change must be notified after text change if it occurs.
+  // Therefore, we don't need to query text content again here.
+  if (MOZ_UNLIKELY(!mContentCache.SetSelection(
+          this, aIMENotification.mSelectionChangeData))) {
+    // If there is no text cache yet, caching text will cache selection too.
+    // Therefore, in the case, we don't need to notify IME of selection change
+    // right now.
+    return NS_OK;
+  }
+
+  mBrowserChild->SendNotifyIMESelection(mContentCache, aIMENotification);
+
+  return NS_OK;
+}
+
+nsresult PuppetWidget::NotifyIMEOfMouseButtonEvent(
+    const IMENotification& aIMENotification) {
+  MOZ_ASSERT(IMEStateManager::CanSendNotificationToWidget());
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+
+  bool consumedByIME = false;
+  if (!mBrowserChild->SendNotifyIMEMouseButtonEvent(aIMENotification,
+                                                    &consumedByIME)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return consumedByIME ? NS_SUCCESS_EVENT_CONSUMED : NS_OK;
+}
+
+nsresult PuppetWidget::NotifyIMEOfPositionChange(
+    const IMENotification& aIMENotification) {
+  MOZ_ASSERT(IMEStateManager::CanSendNotificationToWidget());
+  if (NS_WARN_IF(!mBrowserChild)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (NS_WARN_IF(!mContentCache.CacheEditorRect(this, &aIMENotification))) {
+    return NS_ERROR_FAILURE;
+  }
+  if (NS_WARN_IF(
+          !mContentCache.CacheCaretAndTextRects(this, &aIMENotification))) {
+    return NS_ERROR_FAILURE;
+  }
+  if (mIMENotificationRequestsOfParent.WantPositionChanged()) {
+    mBrowserChild->SendNotifyIMEPositionChange(mContentCache, aIMENotification);
+  } else {
+    mBrowserChild->SendUpdateContentCache(mContentCache);
+  }
+  return NS_OK;
+}
+
+struct CursorSurface {
+  UniquePtr<char[]> mData;
+  IntSize mSize;
+};
+
+void PuppetWidget::SetCursor(const Cursor& aCursor) {
+  if (!mBrowserChild) {
+    return;
+  }
+
+  const bool force = mUpdateCursor;
+  if (!force && mCursor == aCursor) {
+    return;
+  }
+
+  bool hasCustomCursor = false;
+  Maybe<mozilla::ipc::BigBuffer> customCursorData;
+  size_t length = 0;
+  IntSize customCursorSize;
+  int32_t stride = 0;
+  auto format = SurfaceFormat::B8G8R8A8;
+  ImageResolution resolution = aCursor.mResolution;
+  if (aCursor.IsCustom()) {
+    int32_t width = 0, height = 0;
+    aCursor.mContainer->GetWidth(&width);
+    aCursor.mContainer->GetHeight(&height);
+    const int32_t flags =
+        imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY;
+    RefPtr<SourceSurface> surface;
+    if (width && height &&
+        aCursor.mContainer->GetType() == imgIContainer::TYPE_VECTOR) {
+      // For vector images, scale to device pixels.
+      resolution.ScaleBy(GetDefaultScale().scale);
+      resolution.ApplyInverseTo(width, height);
+      surface = aCursor.mContainer->GetFrameAtSize(
+          {width, height}, imgIContainer::FRAME_CURRENT, flags);
+    } else {
+      // NOTE(emilio): We get the frame at the full size, ignoring resolution,
+      // because we're going to rasterize it, and we'd effectively lose the
+      // extra pixels if we rasterized to CustomCursorSize.
+      surface =
+          aCursor.mContainer->GetFrame(imgIContainer::FRAME_CURRENT, flags);
+    }
+    if (surface) {
+      if (RefPtr<DataSourceSurface> dataSurface = surface->GetDataSurface()) {
+        hasCustomCursor = true;
+        customCursorData =
+            nsContentUtils::GetSurfaceData(*dataSurface, &length, &stride);
+        customCursorSize = dataSurface->GetSize();
+        format = dataSurface->GetFormat();
+      }
+    }
+  }
+
+  if (!mBrowserChild->SendSetCursor(
+          aCursor.mDefaultCursor, hasCustomCursor, std::move(customCursorData),
+          customCursorSize.width, customCursorSize.height, resolution.mX,
+          resolution.mY, stride, format, aCursor.mHotspotX, aCursor.mHotspotY,
+          force)) {
+    return;
+  }
+  mCursor = aCursor;
+  mUpdateCursor = false;
+}
+
+void PuppetWidget::SetChild(PuppetWidget* aChild) {
+  MOZ_ASSERT(this != aChild, "can't parent a widget to itself");
+  MOZ_ASSERT(!aChild->mChild,
+             "fake widget 'hierarchy' only expected to have one level");
+
+  mChild = aChild;
+}
+
+NS_IMETHODIMP
+PuppetWidget::WidgetPaintTask::Run() {
+  if (mWidget) {
+    mWidget->Paint();
+  }
+  return NS_OK;
+}
+
+void PuppetWidget::Paint() {
+  if (!GetCurrentWidgetListener()) return;
+
+  mWidgetPaintTask.Revoke();
+
+  RefPtr<PuppetWidget> strongThis(this);
+
+  GetCurrentWidgetListener()->WillPaintWindow(this);
+
+  if (GetCurrentWidgetListener()) {
+    GetCurrentWidgetListener()->DidPaintWindow();
+  }
+}
+
+void PuppetWidget::PaintNowIfNeeded() {
+  if (IsVisible() && mWidgetPaintTask.IsPending()) {
+    Paint();
+  }
+}
+
+void PuppetWidget::OnMemoryPressure(layers::MemoryPressureReason aWhy) {
+  if (aWhy != MemoryPressureReason::LOW_MEMORY_ONGOING && !mVisible &&
+      mWindowRenderer && mWindowRenderer->AsWebRender() &&
+      XRE_IsContentProcess()) {
+    mWindowRenderer->AsWebRender()->ClearCachedResources();
+  }
+}
+
+bool PuppetWidget::NeedsPaint() {
+  // e10s popups are handled by the parent process, so never should be painted
+  // here
+  return mVisible;
+}
+
+LayoutDeviceIntPoint PuppetWidget::GetChromeOffset() {
+  if (!GetOwningBrowserChild()) {
+    NS_WARNING("PuppetWidget without Tab does not have chrome information.");
+    return LayoutDeviceIntPoint();
+  }
+  return GetOwningBrowserChild()->GetChromeOffset();
+}
+
+LayoutDeviceIntPoint PuppetWidget::WidgetToScreenOffset() {
+  return GetWindowPosition() + WidgetToTopLevelWidgetOffset();
+}
+
+LayoutDeviceIntPoint PuppetWidget::GetWindowPosition() {
+  if (!GetOwningBrowserChild()) {
+    return LayoutDeviceIntPoint();
+  }
+
+  int32_t winX, winY, winW, winH;
+  NS_ENSURE_SUCCESS(GetOwningBrowserChild()->GetDimensions(
+                        DimensionKind::Outer, &winX, &winY, &winW, &winH),
+                    LayoutDeviceIntPoint());
+  return LayoutDeviceIntPoint(winX, winY) +
+         GetOwningBrowserChild()->GetClientOffset();
+}
+
+LayoutDeviceIntRect PuppetWidget::GetScreenBounds() {
+  return LayoutDeviceIntRect(WidgetToScreenOffset(), mBounds.Size());
+}
+
+uint32_t PuppetWidget::GetMaxTouchPoints() const {
+  return mBrowserChild ? mBrowserChild->MaxTouchPoints() : 0;
+}
+
+void PuppetWidget::StartAsyncScrollbarDrag(
+    const AsyncDragMetrics& aDragMetrics) {
+  mBrowserChild->StartScrollbarDrag(aDragMetrics);
+}
+
+ScreenIntMargin PuppetWidget::GetSafeAreaInsets() const {
+  return mSafeAreaInsets;
+}
+
+void PuppetWidget::UpdateSafeAreaInsets(
+    const ScreenIntMargin& aSafeAreaInsets) {
+  mSafeAreaInsets = aSafeAreaInsets;
+}
+
+nsIWidgetListener* PuppetWidget::GetCurrentWidgetListener() {
+  if (!mPreviouslyAttachedWidgetListener || !mAttachedWidgetListener) {
+    return mAttachedWidgetListener;
+  }
+
+  if (mAttachedWidgetListener->GetView()->IsPrimaryFramePaintSuppressed()) {
+    return mPreviouslyAttachedWidgetListener;
+  }
+
+  return mAttachedWidgetListener;
+}
+
+void PuppetWidget::ZoomToRect(const uint32_t& aPresShellId,
+                              const ScrollableLayerGuid::ViewID& aViewId,
+                              const CSSRect& aRect, const uint32_t& aFlags) {
+  if (!mBrowserChild) {
+    return;
+  }
+
+  mBrowserChild->ZoomToRect(aPresShellId, aViewId, aRect, aFlags);
+}
+
+void PuppetWidget::LookUpDictionary(
+    const nsAString& aText, const nsTArray<mozilla::FontRange>& aFontRangeArray,
+    const bool aIsVertical, const LayoutDeviceIntPoint& aPoint) {
+  if (!mBrowserChild) {
+    return;
+  }
+
+  mBrowserChild->SendLookUpDictionary(aText, aFontRangeArray, aIsVertical,
+                                      aPoint);
+}
+
+bool PuppetWidget::HasPendingInputEvent() {
+  if (!mBrowserChild) {
+    return false;
+  }
+
+  bool ret = false;
+
+  mBrowserChild->GetIPCChannel()->PeekMessages(
+      [&ret](const IPC::Message& aMsg) -> bool {
+        if (nsContentUtils::IsMessageInputEvent(aMsg)) {
+          ret = true;
+          return false;  // Stop peeking.
+        }
+        return true;
+      });
+
+  return ret;
+}
+
+// TextEventDispatcherListener
+
+NS_IMETHODIMP
+PuppetWidget::NotifyIME(TextEventDispatcher* aTextEventDispatcher,
+                        const IMENotification& aIMENotification) {
+  MOZ_ASSERT(aTextEventDispatcher == mTextEventDispatcher);
+
+  // If there is different text event dispatcher listener for handling
+  // text event dispatcher, that means that native keyboard events and
+  // IME events are handled in this process.  Therefore, we don't need
+  // to send any requests and notifications to the parent process.
+  if (mNativeTextEventDispatcherListener) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  switch (aIMENotification.mMessage) {
+    case REQUEST_TO_COMMIT_COMPOSITION:
+      return RequestIMEToCommitComposition(false);
+    case REQUEST_TO_CANCEL_COMPOSITION:
+      return RequestIMEToCommitComposition(true);
+    case NOTIFY_IME_OF_FOCUS:
+    case NOTIFY_IME_OF_BLUR:
+      return NotifyIMEOfFocusChange(aIMENotification);
+    case NOTIFY_IME_OF_SELECTION_CHANGE:
+      return NotifyIMEOfSelectionChange(aIMENotification);
+    case NOTIFY_IME_OF_TEXT_CHANGE:
+      return NotifyIMEOfTextChange(aIMENotification);
+    case NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED:
+      return NotifyIMEOfCompositionUpdate(aIMENotification);
+    case NOTIFY_IME_OF_MOUSE_BUTTON_EVENT:
+      return NotifyIMEOfMouseButtonEvent(aIMENotification);
+    case NOTIFY_IME_OF_POSITION_CHANGE:
+      return NotifyIMEOfPositionChange(aIMENotification);
+    default:
+      return NS_ERROR_NOT_IMPLEMENTED;
+  }
+}
+
+NS_IMETHODIMP_(IMENotificationRequests)
+PuppetWidget::GetIMENotificationRequests() {
+  return IMENotificationRequests(
+      mIMENotificationRequestsOfParent.mWantUpdates |
+      IMENotificationRequests::NOTIFY_TEXT_CHANGE |
+      IMENotificationRequests::NOTIFY_POSITION_CHANGE);
+}
+
+NS_IMETHODIMP_(void)
+PuppetWidget::OnRemovedFrom(TextEventDispatcher* aTextEventDispatcher) {
+  MOZ_ASSERT(aTextEventDispatcher == mTextEventDispatcher);
+}
+
+NS_IMETHODIMP_(void)
+PuppetWidget::WillDispatchKeyboardEvent(
+    TextEventDispatcher* aTextEventDispatcher,
+    WidgetKeyboardEvent& aKeyboardEvent, uint32_t aIndexOfKeypress,
+    void* aData) {
+  MOZ_ASSERT(aTextEventDispatcher == mTextEventDispatcher);
+}
+
+nsresult PuppetWidget::SetSystemFont(const nsCString& aFontName) {
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mBrowserChild->SendSetSystemFont(aFontName);
+  return NS_OK;
+}
+
+nsresult PuppetWidget::GetSystemFont(nsCString& aFontName) {
+  if (!mBrowserChild) {
+    return NS_ERROR_FAILURE;
+  }
+  mBrowserChild->SendGetSystemFont(&aFontName);
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/PuppetWidget.h b/widget/PuppetWidget.h
new file mode 100644
index 0000000000..65050bb455
--- /dev/null
+++ b/widget/PuppetWidget.h
@@ -0,0 +1,406 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This "puppet widget" isn't really a platform widget.  It's intended
+ * to be used in widgetless rendering contexts, such as sandboxed
+ * content processes.  If any "real" widgetry is needed, the request
+ * is forwarded to and/or data received from elsewhere.
+ */
+
+#ifndef mozilla_widget_PuppetWidget_h__
+#define mozilla_widget_PuppetWidget_h__
+
+#include "mozilla/gfx/2D.h"
+#include "mozilla/RefPtr.h"
+#include "nsBaseWidget.h"
+#include "nsCOMArray.h"
+#include "nsThreadUtils.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/ContentCache.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/TextEventDispatcherListener.h"
+#include "mozilla/layers/MemoryPressureObserver.h"
+
+namespace mozilla {
+enum class NativeKeyBindingsType : uint8_t;
+
+namespace dom {
+class BrowserChild;
+}  // namespace dom
+
+namespace layers {
+class WebRenderLayerManager;
+}  // namespace layers
+
+namespace widget {
+
+struct AutoCacheNativeKeyCommands;
+
+class PuppetWidget : public nsBaseWidget,
+                     public TextEventDispatcherListener,
+                     public layers::MemoryPressureListener {
+  typedef mozilla::CSSRect CSSRect;
+  typedef mozilla::dom::BrowserChild BrowserChild;
+  typedef mozilla::gfx::DrawTarget DrawTarget;
+  typedef mozilla::layers::WebRenderLayerManager WebRenderLayerManager;
+
+  // Avoiding to make compiler confused between mozilla::widget and nsIWidget.
+  typedef mozilla::widget::TextEventDispatcher TextEventDispatcher;
+  typedef mozilla::widget::TextEventDispatcherListener
+      TextEventDispatcherListener;
+
+  typedef nsBaseWidget Base;
+
+  // The width and height of the "widget" are clamped to this.
+ public:
+  explicit PuppetWidget(BrowserChild* aBrowserChild);
+
+ protected:
+  virtual ~PuppetWidget();
+
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // PuppetWidget creation is infallible, hence InfallibleCreate(), which
+  // Create() calls.
+  using nsBaseWidget::Create;  // for Create signature not overridden here
+  virtual nsresult Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                          const LayoutDeviceIntRect& aRect,
+                          widget::InitData* aInitData = nullptr) override;
+  void InfallibleCreate(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                        const LayoutDeviceIntRect& aRect,
+                        widget::InitData* aInitData = nullptr);
+
+  void InitIMEState();
+
+  virtual already_AddRefed<nsIWidget> CreateChild(
+      const LayoutDeviceIntRect& aRect, widget::InitData* aInitData = nullptr,
+      bool aForceUseIWidgetParent = false) override;
+
+  virtual void Destroy() override;
+
+  virtual void Show(bool aState) override;
+
+  virtual bool IsVisible() const override { return mVisible; }
+
+  // Widget position is controlled by the parent process via BrowserChild.
+  virtual void Move(double aX, double aY) override {}
+
+  virtual void Resize(double aWidth, double aHeight, bool aRepaint) override;
+  virtual void Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) override {
+    if (!mBounds.IsEqualXY(aX, aY)) {
+      NotifyWindowMoved(aX, aY);
+    }
+    mBounds.MoveTo(aX, aY);
+    return Resize(aWidth, aHeight, aRepaint);
+  }
+
+  // XXX/cjones: copying gtk behavior here; unclear what disabling a
+  // widget is supposed to entail
+  virtual void Enable(bool aState) override { mEnabled = aState; }
+  virtual bool IsEnabled() const override { return mEnabled; }
+
+  virtual nsSizeMode SizeMode() override { return mSizeMode; }
+  virtual void SetSizeMode(nsSizeMode aMode) override { mSizeMode = aMode; }
+
+  virtual void SetFocus(Raise, mozilla::dom::CallerType aCallerType) override;
+
+  virtual void Invalidate(const LayoutDeviceIntRect& aRect) override;
+
+  // PuppetWidgets don't have native data, as they're purely nonnative.
+  virtual void* GetNativeData(uint32_t aDataType) override { return nullptr; }
+
+  // PuppetWidgets don't have any concept of titles.
+  virtual nsresult SetTitle(const nsAString& aTitle) override {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  virtual mozilla::LayoutDeviceToLayoutDeviceMatrix4x4
+  WidgetToTopLevelWidgetTransform() override;
+
+  virtual LayoutDeviceIntPoint WidgetToScreenOffset() override;
+
+  virtual LayoutDeviceIntPoint TopLevelWidgetToScreenOffset() override {
+    return GetWindowPosition();
+  }
+
+  int32_t RoundsWidgetCoordinatesTo() override { return mRounding; }
+
+  void InitEvent(WidgetGUIEvent& aEvent,
+                 LayoutDeviceIntPoint* aPoint = nullptr);
+
+  virtual nsresult DispatchEvent(WidgetGUIEvent* aEvent,
+                                 nsEventStatus& aStatus) override;
+  ContentAndAPZEventStatus DispatchInputEvent(
+      WidgetInputEvent* aEvent) override;
+  void SetConfirmedTargetAPZC(
+      uint64_t aInputBlockId,
+      const nsTArray<ScrollableLayerGuid>& aTargets) const override;
+  void UpdateZoomConstraints(
+      const uint32_t& aPresShellId, const ScrollableLayerGuid::ViewID& aViewId,
+      const mozilla::Maybe<ZoomConstraints>& aConstraints) override;
+  bool AsyncPanZoomEnabled() const override;
+
+  MOZ_CAN_RUN_SCRIPT virtual bool GetEditCommands(
+      NativeKeyBindingsType aType, const mozilla::WidgetKeyboardEvent& aEvent,
+      nsTArray<mozilla::CommandInt>& aCommands) override;
+
+  friend struct AutoCacheNativeKeyCommands;
+
+  //
+  // nsBaseWidget methods we override
+  //
+
+  // Documents loaded in child processes are always subdocuments of
+  // other docs in an ancestor process.  To ensure that the
+  // backgrounds of those documents are painted like those of
+  // same-process subdocuments, we force the widget here to be
+  // transparent, which in turn will cause layout to use a transparent
+  // backstop background color.
+  virtual TransparencyMode GetTransparencyMode() override {
+    return TransparencyMode::Transparent;
+  }
+
+  virtual WindowRenderer* GetWindowRenderer() override;
+
+  // This is used for creating remote layer managers and for re-creating
+  // them after a compositor reset. The lambda aInitializeFunc is used to
+  // perform any caller-required initialization for the newly created layer
+  // manager; in the event of a failure, return false and it will destroy the
+  // new layer manager without changing the state of the widget.
+  bool CreateRemoteLayerManager(
+      const std::function<bool(WebRenderLayerManager*)>& aInitializeFunc);
+
+  virtual void SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction) override;
+  virtual InputContext GetInputContext() override;
+  virtual NativeIMEContext GetNativeIMEContext() override;
+  TextEventDispatcherListener* GetNativeTextEventDispatcherListener() override {
+    return mNativeTextEventDispatcherListener
+               ? mNativeTextEventDispatcherListener.get()
+               : this;
+  }
+  void SetNativeTextEventDispatcherListener(
+      TextEventDispatcherListener* aListener) {
+    mNativeTextEventDispatcherListener = aListener;
+  }
+
+  virtual void SetCursor(const Cursor&) override;
+
+  float GetDPI() override { return mDPI; }
+  double GetDefaultScaleInternal() override { return mDefaultScale; }
+
+  virtual bool NeedsPaint() override;
+
+  // Paint the widget immediately if any paints are queued up.
+  void PaintNowIfNeeded();
+
+  virtual BrowserChild* GetOwningBrowserChild() override {
+    return mBrowserChild;
+  }
+
+  void UpdateBackingScaleCache(float aDpi, int32_t aRounding, double aScale) {
+    mDPI = aDpi;
+    mRounding = aRounding;
+    mDefaultScale = aScale;
+  }
+
+  // safe area insets support
+  virtual ScreenIntMargin GetSafeAreaInsets() const override;
+  void UpdateSafeAreaInsets(const ScreenIntMargin& aSafeAreaInsets);
+
+  // Get the offset to the chrome of the window that this tab belongs to.
+  //
+  // NOTE: In OOP iframes this value is zero. You should use
+  // WidgetToTopLevelWidgetTransform instead which is already including the
+  // chrome offset.
+  LayoutDeviceIntPoint GetChromeOffset();
+
+  // Get the screen position of the application window.
+  LayoutDeviceIntPoint GetWindowPosition();
+
+  virtual LayoutDeviceIntRect GetScreenBounds() override;
+
+  virtual nsresult SynthesizeNativeKeyEvent(
+      int32_t aNativeKeyboardLayout, int32_t aNativeKeyCode,
+      uint32_t aModifierFlags, const nsAString& aCharacters,
+      const nsAString& aUnmodifiedCharacters, nsIObserver* aObserver) override;
+  virtual nsresult SynthesizeNativeMouseEvent(
+      LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+      MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+      nsIObserver* aObserver) override;
+  virtual nsresult SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
+                                             nsIObserver* aObserver) override;
+  virtual nsresult SynthesizeNativeMouseScrollEvent(
+      LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage, double aDeltaX,
+      double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+      uint32_t aAdditionalFlags, nsIObserver* aObserver) override;
+  virtual nsresult SynthesizeNativeTouchPoint(uint32_t aPointerId,
+                                              TouchPointerState aPointerState,
+                                              LayoutDeviceIntPoint aPoint,
+                                              double aPointerPressure,
+                                              uint32_t aPointerOrientation,
+                                              nsIObserver* aObserver) override;
+  virtual nsresult SynthesizeNativeTouchPadPinch(
+      TouchpadGesturePhase aEventPhase, float aScale,
+      LayoutDeviceIntPoint aPoint, int32_t aModifierFlags) override;
+  virtual nsresult SynthesizeNativeTouchTap(LayoutDeviceIntPoint aPoint,
+                                            bool aLongTap,
+                                            nsIObserver* aObserver) override;
+  virtual nsresult ClearNativeTouchSequence(nsIObserver* aObserver) override;
+  virtual uint32_t GetMaxTouchPoints() const override;
+  virtual nsresult SynthesizeNativePenInput(uint32_t aPointerId,
+                                            TouchPointerState aPointerState,
+                                            LayoutDeviceIntPoint aPoint,
+                                            double aPressure,
+                                            uint32_t aRotation, int32_t aTiltX,
+                                            int32_t aTiltY, int32_t aButton,
+                                            nsIObserver* aObserver) override;
+
+  virtual nsresult SynthesizeNativeTouchpadDoubleTap(
+      LayoutDeviceIntPoint aPoint, uint32_t aModifierFlags) override;
+
+  virtual nsresult SynthesizeNativeTouchpadPan(TouchpadGesturePhase aEventPhase,
+                                               LayoutDeviceIntPoint aPoint,
+                                               double aDeltaX, double aDeltaY,
+                                               int32_t aModifierFlags,
+                                               nsIObserver* aObserver) override;
+
+  virtual void LockNativePointer() override;
+  virtual void UnlockNativePointer() override;
+
+  virtual void StartAsyncScrollbarDrag(
+      const AsyncDragMetrics& aDragMetrics) override;
+
+  virtual void ZoomToRect(const uint32_t& aPresShellId,
+                          const ScrollableLayerGuid::ViewID& aViewId,
+                          const CSSRect& aRect,
+                          const uint32_t& aFlags) override;
+
+  virtual bool HasPendingInputEvent() override;
+
+  virtual void LookUpDictionary(
+      const nsAString& aText,
+      const nsTArray<mozilla::FontRange>& aFontRangeArray,
+      const bool aIsVertical, const LayoutDeviceIntPoint& aPoint) override;
+
+  nsresult SetSystemFont(const nsCString& aFontName) override;
+  nsresult GetSystemFont(nsCString& aFontName) override;
+
+  // TextEventDispatcherListener
+  using nsBaseWidget::NotifyIME;
+  NS_IMETHOD NotifyIME(TextEventDispatcher* aTextEventDispatcher,
+                       const IMENotification& aNotification) override;
+  NS_IMETHOD_(IMENotificationRequests) GetIMENotificationRequests() override;
+  NS_IMETHOD_(void)
+  OnRemovedFrom(TextEventDispatcher* aTextEventDispatcher) override;
+  NS_IMETHOD_(void)
+  WillDispatchKeyboardEvent(TextEventDispatcher* aTextEventDispatcher,
+                            WidgetKeyboardEvent& aKeyboardEvent,
+                            uint32_t aIndexOfKeypress, void* aData) override;
+
+  virtual void OnMemoryPressure(layers::MemoryPressureReason aWhy) override;
+
+ private:
+  void Paint();
+
+  void SetChild(PuppetWidget* aChild);
+
+  nsresult RequestIMEToCommitComposition(bool aCancel);
+  nsresult NotifyIMEOfFocusChange(const IMENotification& aIMENotification);
+  nsresult NotifyIMEOfSelectionChange(const IMENotification& aIMENotification);
+  nsresult NotifyIMEOfCompositionUpdate(
+      const IMENotification& aIMENotification);
+  nsresult NotifyIMEOfTextChange(const IMENotification& aIMENotification);
+  nsresult NotifyIMEOfMouseButtonEvent(const IMENotification& aIMENotification);
+  nsresult NotifyIMEOfPositionChange(const IMENotification& aIMENotification);
+
+  bool CacheEditorRect();
+  bool CacheCompositionRects(uint32_t& aStartOffset,
+                             nsTArray<LayoutDeviceIntRect>& aRectArray,
+                             uint32_t& aTargetCauseOffset);
+  bool GetCaretRect(LayoutDeviceIntRect& aCaretRect, uint32_t aCaretOffset);
+  uint32_t GetCaretOffset();
+
+  nsIWidgetListener* GetCurrentWidgetListener();
+
+  // When this widget caches input context and currently managed by
+  // IMEStateManager, the cache is valid.
+  bool HaveValidInputContextCache() const;
+
+  class WidgetPaintTask : public Runnable {
+   public:
+    NS_DECL_NSIRUNNABLE
+    explicit WidgetPaintTask(PuppetWidget* widget)
+        : Runnable("PuppetWidget::WidgetPaintTask"), mWidget(widget) {}
+    void Revoke() { mWidget = nullptr; }
+
+   private:
+    PuppetWidget* mWidget;
+  };
+
+  nsRefreshDriver* GetTopLevelRefreshDriver() const;
+
+  // BrowserChild normally holds a strong reference to this PuppetWidget
+  // or its root ancestor, but each PuppetWidget also needs a
+  // reference back to BrowserChild (e.g. to delegate nsIWidget IME calls
+  // to chrome) So we hold a weak reference to BrowserChild here.  Since
+  // it's possible for BrowserChild to outlive the PuppetWidget, we clear
+  // this weak reference in Destroy()
+  BrowserChild* mBrowserChild;
+  // The "widget" to which we delegate events if we don't have an
+  // event handler.
+  RefPtr<PuppetWidget> mChild;
+  nsRevocableEventPtr<WidgetPaintTask> mWidgetPaintTask;
+  RefPtr<layers::MemoryPressureObserver> mMemoryPressureObserver;
+  // XXX/cjones: keeping this around until we teach LayerManager to do
+  // retained-content-only transactions
+  RefPtr<DrawTarget> mDrawTarget;
+  // IME
+  IMENotificationRequests mIMENotificationRequestsOfParent;
+  InputContext mInputContext;
+  // mNativeIMEContext is initialized when this dispatches every composition
+  // event both from parent process's widget and TextEventDispatcher in same
+  // process.  If it hasn't been started composition yet, this isn't necessary
+  // for XP code since there is no TextComposition instance which is caused by
+  // the PuppetWidget instance.
+  NativeIMEContext mNativeIMEContext;
+  ContentCacheInChild mContentCache;
+
+  // The DPI of the parent widget containing this widget.
+  float mDPI = GetFallbackDPI();
+  int32_t mRounding = 1;
+  double mDefaultScale = GetFallbackDefaultScale().scale;
+
+  ScreenIntMargin mSafeAreaInsets;
+
+  RefPtr<TextEventDispatcherListener> mNativeTextEventDispatcherListener;
+
+ protected:
+  bool mEnabled;
+  bool mVisible;
+
+ private:
+  nsSizeMode mSizeMode;
+
+  bool mNeedIMEStateInit;
+  // When remote process requests to commit/cancel a composition, the
+  // composition may have already been committed in the main process.  In such
+  // case, this will receive remaining composition events for the old
+  // composition even after requesting to commit/cancel the old composition
+  // but the TextComposition for the old composition has already been
+  // destroyed. So, until this meets new eCompositionStart, following
+  // composition events should be ignored if this is set to true.
+  bool mIgnoreCompositionEvents;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_PuppetWidget_h__
diff --git a/widget/RemoteLookAndFeel.cpp b/widget/RemoteLookAndFeel.cpp
new file mode 100644
index 0000000000..5eea54496b
--- /dev/null
+++ b/widget/RemoteLookAndFeel.cpp
@@ -0,0 +1,236 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "RemoteLookAndFeel.h"
+
+#include "gfxFont.h"
+#include "MainThreadUtils.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/ResultExtensions.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/Try.h"
+#include "nsXULAppAPI.h"
+
+#include <limits>
+#include <type_traits>
+#include <utility>
+
+namespace mozilla::widget {
+
+// A cached copy of the data extracted by ExtractData.
+//
+// Storing this lets us avoid doing most of the work of ExtractData each
+// time we create a new content process.
+//
+// Only used in the parent process.
+static StaticAutoPtr<FullLookAndFeel> sCachedLookAndFeelData;
+
+RemoteLookAndFeel::RemoteLookAndFeel(FullLookAndFeel&& aData)
+    : mTables(std::move(aData.tables())) {
+  MOZ_ASSERT(XRE_IsContentProcess(),
+             "Only content processes should be using a RemoteLookAndFeel");
+}
+
+RemoteLookAndFeel::~RemoteLookAndFeel() = default;
+
+void RemoteLookAndFeel::SetDataImpl(FullLookAndFeel&& aData) {
+  MOZ_ASSERT(XRE_IsContentProcess(),
+             "Only content processes should be using a RemoteLookAndFeel");
+  MOZ_ASSERT(NS_IsMainThread());
+  mTables = std::move(aData.tables());
+}
+
+namespace {
+
+// Some lnf values are somewhat expensive to get, and are not needed in child
+// processes, so we can avoid querying them.
+bool IsNeededInChildProcess(LookAndFeel::IntID aId) {
+  switch (aId) {
+    case LookAndFeel::IntID::AlertNotificationOrigin:
+      return false;  // see bug 1703205
+    default:
+      return true;
+  }
+}
+
+template <typename Item, typename UInt, typename ID>
+Result<const Item*, nsresult> MapLookup(const nsTArray<Item>& aItems,
+                                        const nsTArray<UInt>& aMap, ID aID) {
+  UInt mapped = aMap[static_cast<size_t>(aID)];
+
+  if (mapped == std::numeric_limits<UInt>::max()) {
+    return Err(NS_ERROR_NOT_IMPLEMENTED);
+  }
+
+  return &aItems[static_cast<size_t>(mapped)];
+}
+
+template <typename Item, typename UInt, typename Id>
+void AddToMap(nsTArray<Item>& aItems, nsTArray<UInt>& aMap, Id aId,
+              Maybe<Item>&& aNewItem) {
+  auto mapIndex = size_t(aId);
+  aMap.EnsureLengthAtLeast(mapIndex + 1);
+  if (aNewItem.isNothing()) {
+    aMap[mapIndex] = std::numeric_limits<UInt>::max();
+    return;
+  }
+
+  size_t newIndex = aItems.Length();
+  MOZ_ASSERT(newIndex < std::numeric_limits<UInt>::max());
+
+  // Check if there is an existing value in aItems that we can point to.
+  //
+  // The arrays should be small enough and contain few enough unique
+  // values that sequential search here is reasonable.
+  for (size_t i = 0; i < newIndex; ++i) {
+    if (aItems[i] == aNewItem.ref()) {
+      aMap[mapIndex] = static_cast<UInt>(i);
+      return;
+    }
+  }
+
+  aItems.AppendElement(aNewItem.extract());
+  aMap[mapIndex] = static_cast<UInt>(newIndex);
+}
+
+}  // namespace
+
+nsresult RemoteLookAndFeel::NativeGetColor(ColorID aID, ColorScheme aScheme,
+                                           nscolor& aResult) {
+  const nscolor* result;
+  const bool dark = aScheme == ColorScheme::Dark;
+  MOZ_TRY_VAR(
+      result,
+      MapLookup(dark ? mTables.darkColors() : mTables.lightColors(),
+                dark ? mTables.darkColorMap() : mTables.lightColorMap(), aID));
+  aResult = *result;
+  return NS_OK;
+}
+
+nsresult RemoteLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      IsNeededInChildProcess(aID),
+      "Querying value that we didn't bother getting from the parent process!");
+
+  const int32_t* result;
+  MOZ_TRY_VAR(result, MapLookup(mTables.ints(), mTables.intMap(), aID));
+  aResult = *result;
+  return NS_OK;
+}
+
+nsresult RemoteLookAndFeel::NativeGetFloat(FloatID aID, float& aResult) {
+  const float* result;
+  MOZ_TRY_VAR(result, MapLookup(mTables.floats(), mTables.floatMap(), aID));
+  aResult = *result;
+  return NS_OK;
+}
+
+bool RemoteLookAndFeel::NativeGetFont(FontID aID, nsString& aFontName,
+                                      gfxFontStyle& aFontStyle) {
+  auto result = MapLookup(mTables.fonts(), mTables.fontMap(), aID);
+  if (result.isErr()) {
+    return false;
+  }
+  const LookAndFeelFont& font = *result.unwrap();
+  return LookAndFeelFontToStyle(font, aFontName, aFontStyle);
+}
+
+char16_t RemoteLookAndFeel::GetPasswordCharacterImpl() {
+  return static_cast<char16_t>(mTables.passwordChar());
+}
+
+bool RemoteLookAndFeel::GetEchoPasswordImpl() { return mTables.passwordEcho(); }
+
+static bool AddIDsToMap(nsXPLookAndFeel* aImpl, FullLookAndFeel* aLf) {
+  using IntID = LookAndFeel::IntID;
+  using FontID = LookAndFeel::FontID;
+  using FloatID = LookAndFeel::FloatID;
+  using ColorID = LookAndFeel::ColorID;
+  using ColorScheme = LookAndFeel::ColorScheme;
+
+  bool anyFromOtherTheme = false;
+  for (auto id : MakeEnumeratedRange(IntID::End)) {
+    if (!IsNeededInChildProcess(id)) {
+      continue;
+    }
+    int32_t theInt;
+    nsresult rv = aImpl->NativeGetInt(id, theInt);
+    AddToMap(aLf->tables().ints(), aLf->tables().intMap(), id,
+             NS_SUCCEEDED(rv) ? Some(theInt) : Nothing{});
+  }
+
+  for (auto id : MakeEnumeratedRange(ColorID::End)) {
+    nscolor theColor;
+    nsresult rv = aImpl->NativeGetColor(id, ColorScheme::Light, theColor);
+    AddToMap(aLf->tables().lightColors(), aLf->tables().lightColorMap(), id,
+             NS_SUCCEEDED(rv) ? Some(theColor) : Nothing{});
+    rv = aImpl->NativeGetColor(id, ColorScheme::Dark, theColor);
+    AddToMap(aLf->tables().darkColors(), aLf->tables().darkColorMap(), id,
+             NS_SUCCEEDED(rv) ? Some(theColor) : Nothing{});
+  }
+
+  for (auto id : MakeEnumeratedRange(FloatID::End)) {
+    float theFloat;
+    nsresult rv = aImpl->NativeGetFloat(id, theFloat);
+    AddToMap(aLf->tables().floats(), aLf->tables().floatMap(), id,
+             NS_SUCCEEDED(rv) ? Some(theFloat) : Nothing{});
+  }
+
+  for (auto id : MakeEnumeratedRange(FontID::End)) {
+    gfxFontStyle fontStyle{};
+
+    nsString name;
+    bool rv = aImpl->NativeGetFont(id, name, fontStyle);
+    Maybe<LookAndFeelFont> maybeFont;
+    if (rv) {
+      maybeFont.emplace(
+          nsXPLookAndFeel::StyleToLookAndFeelFont(name, fontStyle));
+    }
+    AddToMap(aLf->tables().fonts(), aLf->tables().fontMap(), id,
+             std::move(maybeFont));
+  }
+
+  return anyFromOtherTheme;
+}
+
+// static
+const FullLookAndFeel* RemoteLookAndFeel::ExtractData() {
+  MOZ_ASSERT(XRE_IsParentProcess(),
+             "Only parent processes should be extracting LookAndFeel data");
+
+  if (sCachedLookAndFeelData) {
+    return sCachedLookAndFeelData;
+  }
+
+  static bool sInitialized = false;
+  if (!sInitialized) {
+    sInitialized = true;
+    ClearOnShutdown(&sCachedLookAndFeelData);
+  }
+
+  FullLookAndFeel* lf = new FullLookAndFeel{};
+  nsXPLookAndFeel* impl = nsXPLookAndFeel::GetInstance();
+
+  lf->tables().passwordChar() = impl->GetPasswordCharacterImpl();
+  lf->tables().passwordEcho() = impl->GetEchoPasswordImpl();
+
+  AddIDsToMap(impl, lf);
+
+  // This assignment to sCachedLookAndFeelData must be done after the
+  // WithThemeConfiguredForContent call, since it can end up calling RefreshImpl
+  // on the LookAndFeel, which will clear out sCachedTables.
+  sCachedLookAndFeelData = lf;
+  return sCachedLookAndFeelData;
+}
+
+void RemoteLookAndFeel::ClearCachedData() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  sCachedLookAndFeelData = nullptr;
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/RemoteLookAndFeel.h b/widget/RemoteLookAndFeel.h
new file mode 100644
index 0000000000..918f3392ec
--- /dev/null
+++ b/widget/RemoteLookAndFeel.h
@@ -0,0 +1,63 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_RemoteLookAndFeel_h__
+#define mozilla_widget_RemoteLookAndFeel_h__
+
+#include "mozilla/widget/nsXPLookAndFeel.h"
+#include "mozilla/widget/LookAndFeelTypes.h"
+
+namespace mozilla::widget {
+
+/**
+ * A LookAndFeel implementation whose native values are provided by the
+ * parent process.
+ */
+class RemoteLookAndFeel final : public nsXPLookAndFeel {
+ public:
+  explicit RemoteLookAndFeel(FullLookAndFeel&& aTables);
+
+  virtual ~RemoteLookAndFeel();
+
+  void NativeInit() override {}
+
+  nsresult NativeGetInt(IntID, int32_t& aResult) override;
+  nsresult NativeGetFloat(FloatID, float& aResult) override;
+  nsresult NativeGetColor(ColorID, ColorScheme, nscolor& aResult) override;
+  bool NativeGetFont(FontID aID, nsString& aFontName,
+                     gfxFontStyle& aFontStyle) override;
+
+  char16_t GetPasswordCharacterImpl() override;
+  bool GetEchoPasswordImpl() override;
+
+  // Sets the LookAndFeel data to be used by this content process' singleton
+  // RemoteLookAndFeel object.
+  void SetDataImpl(FullLookAndFeel&& aTables) override;
+
+  // Extracts the data from the platform's default LookAndFeel implementation.
+  //
+  // This is called in the parent process to obtain the data to send down to
+  // content processes when they are created (and when the OS theme changes).
+  //
+  // Note that the pointer returned from here is only valid until the next time
+  // ClearCachedData is called.
+  static const FullLookAndFeel* ExtractData();
+
+  // Clears any cached extracted data from the platform's default LookAndFeel
+  // implementation.
+  //
+  // This is called in the parent process when the default LookAndFeel is
+  // refreshed, to invalidate sCachedLookAndFeelData.
+  static void ClearCachedData();
+
+ private:
+  LookAndFeelTables mTables;
+};
+
+}  // namespace mozilla::widget
+
+#endif  // mozilla_widget_RemoteLookAndFeel_h__
diff --git a/widget/Screen.cpp b/widget/Screen.cpp
new file mode 100644
index 0000000000..71a1624624
--- /dev/null
+++ b/widget/Screen.cpp
@@ -0,0 +1,191 @@
+/* -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 2; -*- */
+/* vim: set sw=2 ts=8 et tw=80 : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Screen.h"
+
+#include "mozilla/dom/DOMTypes.h"
+#include "mozilla/dom/ScreenBinding.h"
+#include "mozilla/Hal.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/StaticPrefs_layout.h"
+
+namespace mozilla::widget {
+
+NS_IMPL_ISUPPORTS(Screen, nsIScreen)
+
+static hal::ScreenOrientation EffectiveOrientation(
+    hal::ScreenOrientation aOrientation, const LayoutDeviceIntRect& aRect) {
+  if (aOrientation == hal::ScreenOrientation::None) {
+    return aRect.Width() >= aRect.Height()
+               ? hal::ScreenOrientation::LandscapePrimary
+               : hal::ScreenOrientation::PortraitPrimary;
+  }
+  return aOrientation;
+}
+
+Screen::Screen(LayoutDeviceIntRect aRect, LayoutDeviceIntRect aAvailRect,
+               uint32_t aPixelDepth, uint32_t aColorDepth,
+               uint32_t aRefreshRate, DesktopToLayoutDeviceScale aContentsScale,
+               CSSToLayoutDeviceScale aDefaultCssScale, float aDPI,
+               IsPseudoDisplay aIsPseudoDisplay,
+               hal::ScreenOrientation aOrientation,
+               OrientationAngle aOrientationAngle)
+    : mRect(aRect),
+      mAvailRect(aAvailRect),
+      mRectDisplayPix(RoundedToInt(aRect / aContentsScale)),
+      mAvailRectDisplayPix(RoundedToInt(aAvailRect / aContentsScale)),
+      mPixelDepth(aPixelDepth),
+      mColorDepth(aColorDepth),
+      mRefreshRate(aRefreshRate),
+      mContentsScale(aContentsScale),
+      mDefaultCssScale(aDefaultCssScale),
+      mDPI(aDPI),
+      mScreenOrientation(EffectiveOrientation(aOrientation, aRect)),
+      mOrientationAngle(aOrientationAngle),
+      mIsPseudoDisplay(aIsPseudoDisplay == IsPseudoDisplay::Yes) {}
+
+Screen::Screen(const dom::ScreenDetails& aScreen)
+    : mRect(aScreen.rect()),
+      mAvailRect(aScreen.availRect()),
+      mRectDisplayPix(aScreen.rectDisplayPix()),
+      mAvailRectDisplayPix(aScreen.availRectDisplayPix()),
+      mPixelDepth(aScreen.pixelDepth()),
+      mColorDepth(aScreen.colorDepth()),
+      mRefreshRate(aScreen.refreshRate()),
+      mContentsScale(aScreen.contentsScaleFactor()),
+      mDefaultCssScale(aScreen.defaultCSSScaleFactor()),
+      mDPI(aScreen.dpi()),
+      mScreenOrientation(aScreen.orientation()),
+      mOrientationAngle(aScreen.orientationAngle()),
+      mIsPseudoDisplay(aScreen.isPseudoDisplay()) {}
+
+Screen::Screen(const Screen& aOther)
+    : mRect(aOther.mRect),
+      mAvailRect(aOther.mAvailRect),
+      mRectDisplayPix(aOther.mRectDisplayPix),
+      mAvailRectDisplayPix(aOther.mAvailRectDisplayPix),
+      mPixelDepth(aOther.mPixelDepth),
+      mColorDepth(aOther.mColorDepth),
+      mRefreshRate(aOther.mRefreshRate),
+      mContentsScale(aOther.mContentsScale),
+      mDefaultCssScale(aOther.mDefaultCssScale),
+      mDPI(aOther.mDPI),
+      mScreenOrientation(aOther.mScreenOrientation),
+      mOrientationAngle(aOther.mOrientationAngle),
+      mIsPseudoDisplay(aOther.mIsPseudoDisplay) {}
+
+dom::ScreenDetails Screen::ToScreenDetails() const {
+  return dom::ScreenDetails(
+      mRect, mRectDisplayPix, mAvailRect, mAvailRectDisplayPix, mPixelDepth,
+      mColorDepth, mRefreshRate, mContentsScale, mDefaultCssScale, mDPI,
+      mScreenOrientation, mOrientationAngle, mIsPseudoDisplay);
+}
+
+NS_IMETHODIMP
+Screen::GetRect(int32_t* aOutLeft, int32_t* aOutTop, int32_t* aOutWidth,
+                int32_t* aOutHeight) {
+  mRect.GetRect(aOutLeft, aOutTop, aOutWidth, aOutHeight);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Screen::GetRectDisplayPix(int32_t* aOutLeft, int32_t* aOutTop,
+                          int32_t* aOutWidth, int32_t* aOutHeight) {
+  mRectDisplayPix.GetRect(aOutLeft, aOutTop, aOutWidth, aOutHeight);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Screen::GetAvailRect(int32_t* aOutLeft, int32_t* aOutTop, int32_t* aOutWidth,
+                     int32_t* aOutHeight) {
+  mAvailRect.GetRect(aOutLeft, aOutTop, aOutWidth, aOutHeight);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Screen::GetAvailRectDisplayPix(int32_t* aOutLeft, int32_t* aOutTop,
+                               int32_t* aOutWidth, int32_t* aOutHeight) {
+  mAvailRectDisplayPix.GetRect(aOutLeft, aOutTop, aOutWidth, aOutHeight);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Screen::GetColorGamut(dom::ScreenColorGamut* aScreenColorGamut) {
+  // TODO(zrhoffman, bug 1771373): Return a wider color gamut when one is
+  // available
+  *aScreenColorGamut = dom::ScreenColorGamut::Srgb;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Screen::GetPixelDepth(int32_t* aPixelDepth) {
+  *aPixelDepth = mPixelDepth;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Screen::GetColorDepth(int32_t* aColorDepth) {
+  *aColorDepth = mColorDepth;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Screen::GetContentsScaleFactor(double* aOutScale) {
+  *aOutScale = mContentsScale.scale;
+  return NS_OK;
+}
+
+CSSToLayoutDeviceScale Screen::GetCSSToLayoutDeviceScale(
+    IncludeOSZoom aIncludeOSZoom) const {
+  auto scale = CSSToLayoutDeviceScale(StaticPrefs::layout_css_devPixelsPerPx());
+  if (scale.scale <= 0.0) {
+    scale = mDefaultCssScale;
+  }
+  if (bool(aIncludeOSZoom)) {
+    scale.scale *= LookAndFeel::SystemZoomSettings().mFullZoom;
+  }
+  return scale;
+}
+
+NS_IMETHODIMP
+Screen::GetDefaultCSSScaleFactor(double* aOutScale) {
+  *aOutScale = GetCSSToLayoutDeviceScale(IncludeOSZoom::Yes).scale;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Screen::GetDpi(float* aDPI) {
+  *aDPI = mDPI;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Screen::GetRefreshRate(int32_t* aRefreshRate) {
+  *aRefreshRate = mRefreshRate;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Screen::GetIsPseudoDisplay(bool* aIsPseudoDisplay) {
+  *aIsPseudoDisplay = mIsPseudoDisplay;
+  return NS_OK;
+}
+
+hal::ScreenOrientation Screen::GetDefaultOrientationType() const {
+  if (mRect.Width() >= mRect.Height()) {
+    if (mOrientationAngle == 0 || mOrientationAngle == 180) {
+      return hal::ScreenOrientation::LandscapePrimary;
+    }
+    return hal::ScreenOrientation::PortraitPrimary;
+  }
+
+  if (mOrientationAngle == 0 || mOrientationAngle == 180) {
+    return hal::ScreenOrientation::PortraitPrimary;
+  }
+  return hal::ScreenOrientation::LandscapePrimary;
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/Screen.h b/widget/Screen.h
new file mode 100644
index 0000000000..f3f8b4a628
--- /dev/null
+++ b/widget/Screen.h
@@ -0,0 +1,84 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_Screen_h
+#define mozilla_widget_Screen_h
+
+#include "nsIScreen.h"
+
+#include "Units.h"
+#include "mozilla/HalScreenConfiguration.h"  // For hal::ScreenOrientation
+
+namespace mozilla {
+namespace dom {
+class ScreenDetails;
+}  // namespace dom
+
+namespace widget {
+
+class Screen final : public nsIScreen {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISCREEN
+
+  using OrientationAngle = uint16_t;
+  enum class IsPseudoDisplay : bool { No, Yes };
+
+  Screen(LayoutDeviceIntRect aRect, LayoutDeviceIntRect aAvailRect,
+         uint32_t aPixelDepth, uint32_t aColorDepth, uint32_t aRefreshRate,
+         DesktopToLayoutDeviceScale aContentsScale,
+         CSSToLayoutDeviceScale aDefaultCssScale, float aDpi, IsPseudoDisplay,
+         hal::ScreenOrientation = hal::ScreenOrientation::None,
+         OrientationAngle = 0);
+  explicit Screen(const dom::ScreenDetails& aScreenDetails);
+  Screen(const Screen& aOther);
+
+  dom::ScreenDetails ToScreenDetails() const;
+
+  OrientationAngle GetOrientationAngle() const { return mOrientationAngle; }
+  hal::ScreenOrientation GetOrientationType() const {
+    return mScreenOrientation;
+  }
+
+  /**
+   * Return default orientation type that angle is 0.
+   * This returns LandscapePrimary or PortraitPrimary.
+   */
+  hal::ScreenOrientation GetDefaultOrientationType() const;
+
+  float GetDPI() const { return mDPI; }
+
+  const LayoutDeviceIntRect& GetRect() const { return mRect; }
+  const LayoutDeviceIntRect& GetAvailRect() const { return mAvailRect; }
+  const DesktopToLayoutDeviceScale& GetContentsScaleFactor() const {
+    return mContentsScale;
+  }
+
+  enum class IncludeOSZoom : bool { No, Yes };
+  CSSToLayoutDeviceScale GetCSSToLayoutDeviceScale(IncludeOSZoom) const;
+
+ private:
+  virtual ~Screen() = default;
+
+  const LayoutDeviceIntRect mRect;
+  const LayoutDeviceIntRect mAvailRect;
+  const DesktopIntRect mRectDisplayPix;
+  const DesktopIntRect mAvailRectDisplayPix;
+  const uint32_t mPixelDepth;
+  const uint32_t mColorDepth;
+  const uint32_t mRefreshRate;
+  const DesktopToLayoutDeviceScale mContentsScale;
+  const CSSToLayoutDeviceScale mDefaultCssScale;
+  const float mDPI;
+  const hal::ScreenOrientation mScreenOrientation;
+  const OrientationAngle mOrientationAngle;
+  const bool mIsPseudoDisplay;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/ScreenManager.cpp b/widget/ScreenManager.cpp
new file mode 100644
index 0000000000..58e20806eb
--- /dev/null
+++ b/widget/ScreenManager.cpp
@@ -0,0 +1,261 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScreenManager.h"
+
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/DOMTypes.h"
+#include "mozilla/Logging.h"
+#include "mozilla/StaticPtr.h"
+#ifdef MOZ_WAYLAND
+#  include "mozilla/WidgetUtilsGtk.h"
+#endif /* MOZ_WAYLAND */
+
+static mozilla::LazyLogModule sScreenLog("WidgetScreen");
+
+namespace mozilla::widget {
+
+NS_IMPL_ISUPPORTS(ScreenManager, nsIScreenManager)
+
+ScreenManager::ScreenManager() = default;
+
+ScreenManager::~ScreenManager() = default;
+
+static StaticRefPtr<ScreenManager> sSingleton;
+
+ScreenManager& ScreenManager::GetSingleton() {
+  if (!sSingleton) {
+    sSingleton = new ScreenManager();
+    ClearOnShutdown(&sSingleton);
+  }
+  return *sSingleton;
+}
+
+already_AddRefed<ScreenManager> ScreenManager::GetAddRefedSingleton() {
+  RefPtr<ScreenManager> sm = &GetSingleton();
+  return sm.forget();
+}
+
+void ScreenManager::SetHelper(UniquePtr<Helper> aHelper) {
+  mHelper = std::move(aHelper);
+}
+
+// static
+void ScreenManager::Refresh(nsTArray<RefPtr<Screen>>&& aScreens) {
+  if (PastShutdownPhase(ShutdownPhase::XPCOMShutdown)) {
+    // We don't refresh screen data if starting XPCOM shutdown path.
+    // GetSingleton returns invalid data since it is freed.
+    return;
+  }
+  MOZ_LOG(sScreenLog, LogLevel::Debug, ("Refresh screens"));
+  GetSingleton().RefreshInternal(std::move(aScreens));
+}
+
+void ScreenManager::Refresh(nsTArray<mozilla::dom::ScreenDetails>&& aScreens) {
+  MOZ_LOG(sScreenLog, LogLevel::Debug, ("Refresh screens from IPC"));
+
+  AutoTArray<RefPtr<Screen>, 4> screens;
+  for (auto& screen : aScreens) {
+    screens.AppendElement(new Screen(screen));
+  }
+  RefreshInternal(std::move(screens));
+}
+
+void ScreenManager::RefreshInternal(nsTArray<RefPtr<Screen>>&& aScreens) {
+  mScreenList = std::move(aScreens);
+
+  CopyScreensToAllRemotesIfIsParent();
+  if (nsCOMPtr<nsIObserverService> s = services::GetObserverService()) {
+    s->NotifyObservers(nullptr, "screen-information-changed", nullptr);
+  }
+}
+
+template <class Range>
+void ScreenManager::CopyScreensToRemoteRange(Range aRemoteRange) {
+  AutoTArray<dom::ScreenDetails, 4> screens;
+  for (auto& screen : mScreenList) {
+    screens.AppendElement(screen->ToScreenDetails());
+  }
+  for (auto cp : aRemoteRange) {
+    MOZ_LOG(sScreenLog, LogLevel::Debug,
+            ("Send screens to [Pid %d]", cp->Pid()));
+    if (!cp->SendRefreshScreens(screens)) {
+      MOZ_LOG(sScreenLog, LogLevel::Error,
+              ("SendRefreshScreens to [Pid %d] failed", cp->Pid()));
+    }
+  }
+}
+
+void ScreenManager::CopyScreensToRemote(dom::ContentParent* aContentParent) {
+  MOZ_ASSERT(aContentParent);
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  auto range = {aContentParent};
+  CopyScreensToRemoteRange(range);
+}
+
+void ScreenManager::CopyScreensToAllRemotesIfIsParent() {
+  if (XRE_IsContentProcess()) {
+    return;
+  }
+
+  MOZ_LOG(sScreenLog, LogLevel::Debug, ("Refreshing all ContentParents"));
+
+  CopyScreensToRemoteRange(
+      dom::ContentParent::AllProcesses(dom::ContentParent::eLive));
+}
+
+// Returns the screen that contains the rectangle. If the rect overlaps
+// multiple screens, it picks the screen with the greatest area of intersection.
+//
+// The coordinates are in desktop pixels.
+//
+NS_IMETHODIMP
+ScreenManager::ScreenForRect(int32_t aX, int32_t aY, int32_t aWidth,
+                             int32_t aHeight, nsIScreen** aOutScreen) {
+  DesktopIntRect rect(aX, aY, aWidth, aHeight);
+  nsCOMPtr<nsIScreen> screen = ScreenForRect(rect);
+  screen.forget(aOutScreen);
+  return NS_OK;
+}
+
+already_AddRefed<Screen> ScreenManager::ScreenForRect(
+    const DesktopIntRect& aRect) {
+#if defined(MOZ_WAYLAND) && defined(MOZ_LOGGING)
+  static bool inWayland = GdkIsWaylandDisplay();
+  if (inWayland) {
+    MOZ_LOG(sScreenLog, LogLevel::Warning,
+            ("Getting screen in wayland, primary display will be returned."));
+  }
+#endif
+
+  if (mScreenList.IsEmpty()) {
+    MOZ_LOG(sScreenLog, LogLevel::Warning,
+            ("No screen available. This can happen in xpcshell."));
+    auto screen = MakeRefPtr<Screen>(
+        LayoutDeviceIntRect(), LayoutDeviceIntRect(), 0, 0, 0,
+        DesktopToLayoutDeviceScale(), CSSToLayoutDeviceScale(), 96 /* dpi */,
+        Screen::IsPseudoDisplay::No, hal::ScreenOrientation::None, 0);
+    return screen.forget();
+  }
+
+  // Optimize for the common case. If the number of screens is only
+  // one then just return the primary screen.
+  if (mScreenList.Length() == 1) {
+    return GetPrimaryScreen();
+  }
+
+  // which screen should we return?
+  Screen* which = mScreenList[0].get();
+
+  // walk the list of screens and find the one that has the most
+  // surface area.
+  uint32_t area = 0;
+  for (auto& screen : mScreenList) {
+    int32_t x, y, width, height;
+    x = y = width = height = 0;
+    screen->GetRectDisplayPix(&x, &y, &width, &height);
+    // calculate the surface area
+    DesktopIntRect screenRect(x, y, width, height);
+    screenRect.IntersectRect(screenRect, aRect);
+    uint32_t tempArea = screenRect.Area();
+    if (tempArea > area) {
+      which = screen.get();
+      area = tempArea;
+    }
+  }
+
+  // If the rect intersects one or more screen,
+  // return the screen that has the largest intersection.
+  if (area > 0) {
+    RefPtr<Screen> ret = which;
+    return ret.forget();
+  }
+
+  // If the rect does not intersect a screen, find
+  // a screen that is nearest to the rect.
+  uint32_t distance = UINT32_MAX;
+  for (auto& screen : mScreenList) {
+    int32_t x, y, width, height;
+    x = y = width = height = 0;
+    screen->GetRectDisplayPix(&x, &y, &width, &height);
+
+    uint32_t distanceX = 0;
+    if (aRect.x > (x + width)) {
+      distanceX = aRect.x - (x + width);
+    } else if (aRect.XMost() < x) {
+      distanceX = x - aRect.XMost();
+    }
+
+    uint32_t distanceY = 0;
+    if (aRect.y > (y + height)) {
+      distanceY = aRect.y - (y + height);
+    } else if (aRect.YMost() < y) {
+      distanceY = y - aRect.YMost();
+    }
+
+    uint32_t tempDistance = distanceX * distanceX + distanceY * distanceY;
+    if (tempDistance < distance) {
+      which = screen.get();
+      distance = tempDistance;
+      if (distance == 0) {
+        break;
+      }
+    }
+  }
+
+  RefPtr<Screen> ret = which;
+  return ret.forget();
+}
+
+// The screen with the menubar/taskbar. This shouldn't be needed very
+// often.
+//
+already_AddRefed<Screen> ScreenManager::GetPrimaryScreen() {
+  if (mScreenList.IsEmpty()) {
+    MOZ_LOG(sScreenLog, LogLevel::Warning,
+            ("No screen available. This can happen in xpcshell."));
+    return MakeAndAddRef<Screen>(
+        LayoutDeviceIntRect(), LayoutDeviceIntRect(), 0, 0, 0,
+        DesktopToLayoutDeviceScale(), CSSToLayoutDeviceScale(), 96 /* dpi */,
+        Screen::IsPseudoDisplay::No, hal::ScreenOrientation::None, 0);
+  }
+
+  return do_AddRef(mScreenList[0]);
+}
+
+NS_IMETHODIMP
+ScreenManager::GetPrimaryScreen(nsIScreen** aPrimaryScreen) {
+  nsCOMPtr<nsIScreen> screen = GetPrimaryScreen();
+  screen.forget(aPrimaryScreen);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ScreenManager::GetTotalScreenPixels(int64_t* aTotalScreenPixels) {
+  MOZ_ASSERT(aTotalScreenPixels);
+
+  if (mScreenList.IsEmpty()) {
+    MOZ_LOG(sScreenLog, LogLevel::Warning,
+            ("No screen available. This can happen in xpcshell."));
+    *aTotalScreenPixels = 0;
+    return NS_OK;
+  }
+
+  int64_t pixels = 0;
+  for (auto& screen : mScreenList) {
+    int32_t x, y, width, height;
+    x = y = width = height = 0;
+    screen->GetRect(&x, &y, &width, &height);
+    pixels += width * height;
+  }
+
+  *aTotalScreenPixels = pixels;
+  return NS_OK;
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/ScreenManager.h b/widget/ScreenManager.h
new file mode 100644
index 0000000000..7c40b9fcdb
--- /dev/null
+++ b/widget/ScreenManager.h
@@ -0,0 +1,66 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_ScreenManager_h
+#define mozilla_widget_ScreenManager_h
+
+#include "nsIScreenManager.h"
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/widget/Screen.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+namespace dom {
+class ContentParent;
+class ScreenDetails;
+}  // namespace dom
+}  // namespace mozilla
+
+namespace mozilla::widget {
+
+class ScreenManager final : public nsIScreenManager {
+ public:
+  class Helper {
+   public:
+    virtual ~Helper() = default;
+  };
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISCREENMANAGER
+
+  static ScreenManager& GetSingleton();
+  static already_AddRefed<ScreenManager> GetAddRefedSingleton();
+
+  void SetHelper(UniquePtr<Helper> aHelper);
+  static void Refresh(nsTArray<RefPtr<Screen>>&& aScreens);
+  void Refresh(nsTArray<mozilla::dom::ScreenDetails>&& aScreens);
+  void CopyScreensToRemote(mozilla::dom::ContentParent* aContentParent);
+  already_AddRefed<Screen> GetPrimaryScreen();
+  already_AddRefed<Screen> ScreenForRect(const DesktopIntRect& aRect);
+
+  const nsTArray<RefPtr<Screen>>& CurrentScreenList() const {
+    return mScreenList;
+  }
+
+ private:
+  ScreenManager();
+  virtual ~ScreenManager();
+
+  void RefreshInternal(nsTArray<RefPtr<Screen>>&& aScreens);
+  template <class Range>
+  void CopyScreensToRemoteRange(Range aRemoteRange);
+  void CopyScreensToAllRemotesIfIsParent();
+
+  AutoTArray<RefPtr<Screen>, 4> mScreenList;
+  UniquePtr<Helper> mHelper;
+};
+
+}  // namespace mozilla::widget
+
+#endif  // mozilla_widget_ScreenManager_h
diff --git a/widget/ScrollbarDrawing.cpp b/widget/ScrollbarDrawing.cpp
new file mode 100644
index 0000000000..43bda00411
--- /dev/null
+++ b/widget/ScrollbarDrawing.cpp
@@ -0,0 +1,424 @@
+/* -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 2; -*- */
+/* vim: set sw=2 ts=8 et tw=80 : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScrollbarDrawing.h"
+
+#include "mozilla/RelativeLuminanceUtils.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsContainerFrame.h"
+#include "nsDeviceContext.h"
+#include "nsIFrame.h"
+#include "nsLayoutUtils.h"
+#include "nsLookAndFeel.h"
+#include "nsNativeTheme.h"
+
+using namespace mozilla::gfx;
+
+namespace mozilla::widget {
+
+using mozilla::RelativeLuminanceUtils;
+
+/* static */
+auto ScrollbarDrawing::GetDPIRatioForScrollbarPart(const nsPresContext* aPc)
+    -> DPIRatio {
+  DPIRatio ratio(
+      float(AppUnitsPerCSSPixel()) /
+      float(aPc->DeviceContext()->AppUnitsPerDevPixelAtUnitFullZoom()));
+  if (aPc->IsPrintPreview()) {
+    ratio.scale *= aPc->GetPrintPreviewScaleForSequenceFrameOrScrollbars();
+  }
+  if (mKind == Kind::Cocoa) {
+    return DPIRatio(ratio.scale >= 2.0f ? 2.0f : 1.0f);
+  }
+  return ratio;
+}
+
+/*static*/
+nsIFrame* ScrollbarDrawing::GetParentScrollbarFrame(nsIFrame* aFrame) {
+  // Walk our parents to find a scrollbar frame
+  nsIFrame* scrollbarFrame = aFrame;
+  do {
+    if (scrollbarFrame->IsScrollbarFrame()) {
+      break;
+    }
+  } while ((scrollbarFrame = scrollbarFrame->GetParent()));
+
+  // We return null if we can't find a parent scrollbar frame
+  return scrollbarFrame;
+}
+
+/*static*/
+bool ScrollbarDrawing::IsParentScrollbarRolledOver(nsIFrame* aFrame) {
+  nsIFrame* scrollbarFrame = GetParentScrollbarFrame(aFrame);
+  return aFrame->PresContext()->UseOverlayScrollbars()
+             ? nsNativeTheme::CheckBooleanAttr(scrollbarFrame, nsGkAtoms::hover)
+             : nsNativeTheme::GetContentState(scrollbarFrame,
+                                              StyleAppearance::None)
+                   .HasState(ElementState::HOVER);
+}
+
+/*static*/
+bool ScrollbarDrawing::IsParentScrollbarHoveredOrActive(nsIFrame* aFrame) {
+  nsIFrame* scrollbarFrame = GetParentScrollbarFrame(aFrame);
+  return scrollbarFrame &&
+         scrollbarFrame->GetContent()
+             ->AsElement()
+             ->State()
+             .HasAtLeastOneOfStates(ElementState::HOVER | ElementState::ACTIVE);
+}
+
+/*static*/
+bool ScrollbarDrawing::IsScrollbarWidthThin(const ComputedStyle& aStyle) {
+  auto scrollbarWidth = aStyle.StyleUIReset()->ScrollbarWidth();
+  return scrollbarWidth == StyleScrollbarWidth::Thin;
+}
+
+/*static*/
+bool ScrollbarDrawing::IsScrollbarWidthThin(nsIFrame* aFrame) {
+  ComputedStyle* style = nsLayoutUtils::StyleForScrollbar(aFrame);
+  return IsScrollbarWidthThin(*style);
+}
+
+CSSIntCoord ScrollbarDrawing::GetCSSScrollbarSize(StyleScrollbarWidth aWidth,
+                                                  Overlay aOverlay) const {
+  return mScrollbarSize[aWidth == StyleScrollbarWidth::Thin]
+                       [aOverlay == Overlay::Yes];
+}
+
+void ScrollbarDrawing::ConfigureScrollbarSize(StyleScrollbarWidth aWidth,
+                                              Overlay aOverlay,
+                                              CSSIntCoord aSize) {
+  mScrollbarSize[aWidth == StyleScrollbarWidth::Thin]
+                [aOverlay == Overlay::Yes] = aSize;
+}
+
+void ScrollbarDrawing::ConfigureScrollbarSize(CSSIntCoord aSize) {
+  ConfigureScrollbarSize(StyleScrollbarWidth::Auto, Overlay::No, aSize);
+  ConfigureScrollbarSize(StyleScrollbarWidth::Auto, Overlay::Yes, aSize);
+  ConfigureScrollbarSize(StyleScrollbarWidth::Thin, Overlay::No, aSize / 2);
+  ConfigureScrollbarSize(StyleScrollbarWidth::Thin, Overlay::Yes, aSize / 2);
+}
+
+LayoutDeviceIntCoord ScrollbarDrawing::GetScrollbarSize(
+    const nsPresContext* aPresContext, StyleScrollbarWidth aWidth,
+    Overlay aOverlay) {
+  return (CSSCoord(GetCSSScrollbarSize(aWidth, aOverlay)) *
+          GetDPIRatioForScrollbarPart(aPresContext))
+      .Rounded();
+}
+
+LayoutDeviceIntCoord ScrollbarDrawing::GetScrollbarSize(
+    const nsPresContext* aPresContext, nsIFrame* aFrame) {
+  auto* style = nsLayoutUtils::StyleForScrollbar(aFrame);
+  auto width = style->StyleUIReset()->ScrollbarWidth();
+  auto overlay =
+      aPresContext->UseOverlayScrollbars() ? Overlay::Yes : Overlay::No;
+  return GetScrollbarSize(aPresContext, width, overlay);
+}
+
+bool ScrollbarDrawing::IsScrollbarTrackOpaque(nsIFrame* aFrame) {
+  auto trackColor = ComputeScrollbarTrackColor(
+      aFrame, *nsLayoutUtils::StyleForScrollbar(aFrame),
+      aFrame->PresContext()->Document()->State(),
+      Colors(aFrame, StyleAppearance::ScrollbartrackVertical));
+  return trackColor.a == 1.0f;
+}
+
+sRGBColor ScrollbarDrawing::ComputeScrollbarTrackColor(
+    nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const DocumentState& aDocumentState, const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    return aColors.System(StyleSystemColor::Window);
+  }
+  const nsStyleUI* ui = aStyle.StyleUI();
+  if (ui->mScrollbarColor.IsColors()) {
+    return sRGBColor::FromABGR(
+        ui->mScrollbarColor.AsColors().track.CalcColor(aStyle));
+  }
+  static constexpr sRGBColor sDefaultDarkTrackColor =
+      sRGBColor::FromU8(20, 20, 25, 77);
+  static constexpr sRGBColor sDefaultTrackColor(
+      gfx::sRGBColor::UnusualFromARGB(0xfff0f0f0));
+
+  auto systemColor = aDocumentState.HasAllStates(DocumentState::WINDOW_INACTIVE)
+                         ? StyleSystemColor::ThemedScrollbarInactive
+                         : StyleSystemColor::ThemedScrollbar;
+  return aColors.SystemOrElse(systemColor, [&] {
+    return aColors.IsDark() ? sDefaultDarkTrackColor : sDefaultTrackColor;
+  });
+}
+
+// Don't use the theme color for dark scrollbars if it's not a color (if it's
+// grey-ish), as that'd either lack enough contrast, or be close to what we'd do
+// by default anyways.
+sRGBColor ScrollbarDrawing::ComputeScrollbarThumbColor(
+    nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors) {
+  const nsStyleUI* ui = aStyle.StyleUI();
+  if (ui->mScrollbarColor.IsColors()) {
+    return sRGBColor::FromABGR(ThemeColors::AdjustUnthemedScrollbarThumbColor(
+        ui->mScrollbarColor.AsColors().thumb.CalcColor(aStyle), aElementState));
+  }
+
+  auto systemColor = [&] {
+    if (aDocumentState.HasState(DocumentState::WINDOW_INACTIVE)) {
+      return StyleSystemColor::ThemedScrollbarThumbInactive;
+    }
+    if (aElementState.HasState(ElementState::ACTIVE)) {
+      if (aColors.HighContrast()) {
+        return StyleSystemColor::Selecteditem;
+      }
+      return StyleSystemColor::ThemedScrollbarThumbActive;
+    }
+    if (aElementState.HasState(ElementState::HOVER)) {
+      if (aColors.HighContrast()) {
+        return StyleSystemColor::Selecteditem;
+      }
+      return StyleSystemColor::ThemedScrollbarThumbHover;
+    }
+    if (aColors.HighContrast()) {
+      return StyleSystemColor::Windowtext;
+    }
+    return StyleSystemColor::ThemedScrollbarThumb;
+  }();
+
+  return aColors.SystemOrElse(systemColor, [&] {
+    const nscolor unthemedColor = aColors.IsDark() ? NS_RGBA(249, 249, 250, 102)
+                                                   : NS_RGB(0xcd, 0xcd, 0xcd);
+
+    return sRGBColor::FromABGR(ThemeColors::AdjustUnthemedScrollbarThumbColor(
+        unthemedColor, aElementState));
+  });
+}
+
+template <typename PaintBackendData>
+bool ScrollbarDrawing::DoPaintDefaultScrollbar(
+    PaintBackendData& aPaintData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  const bool overlay = aFrame->PresContext()->UseOverlayScrollbars();
+  if (overlay && !aElementState.HasAtLeastOneOfStates(ElementState::HOVER |
+                                                      ElementState::ACTIVE)) {
+    return true;
+  }
+  const auto color =
+      ComputeScrollbarTrackColor(aFrame, aStyle, aDocumentState, aColors);
+  if (overlay && mKind == Kind::Win11) {
+    LayoutDeviceCoord radius =
+        (aScrollbarKind == ScrollbarKind::Horizontal ? aRect.height
+                                                     : aRect.width) /
+        2.0f;
+    ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, aRect, color,
+                                             sRGBColor(), 0, radius / aDpiRatio,
+                                             aDpiRatio);
+  } else {
+    ThemeDrawing::FillRect(aPaintData, aRect, color);
+  }
+  return true;
+}
+
+bool ScrollbarDrawing::PaintScrollbar(
+    DrawTarget& aDrawTarget, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  return DoPaintDefaultScrollbar(aDrawTarget, aRect, aScrollbarKind, aFrame,
+                                 aStyle, aElementState, aDocumentState, aColors,
+                                 aDpiRatio);
+}
+
+bool ScrollbarDrawing::PaintScrollbar(
+    WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  return DoPaintDefaultScrollbar(aWrData, aRect, aScrollbarKind, aFrame, aStyle,
+                                 aElementState, aDocumentState, aColors,
+                                 aDpiRatio);
+}
+
+template <typename PaintBackendData>
+bool ScrollbarDrawing::DoPaintDefaultScrollCorner(
+    PaintBackendData& aPaintData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const DocumentState& aDocumentState, const Colors& aColors,
+    const DPIRatio& aDpiRatio) {
+  auto scrollbarColor =
+      ComputeScrollbarTrackColor(aFrame, aStyle, aDocumentState, aColors);
+  ThemeDrawing::FillRect(aPaintData, aRect, scrollbarColor);
+  return true;
+}
+
+bool ScrollbarDrawing::PaintScrollCorner(
+    DrawTarget& aDrawTarget, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const DocumentState& aDocumentState, const Colors& aColors,
+    const DPIRatio& aDpiRatio) {
+  return DoPaintDefaultScrollCorner(aDrawTarget, aRect, aScrollbarKind, aFrame,
+                                    aStyle, aDocumentState, aColors, aDpiRatio);
+}
+
+bool ScrollbarDrawing::PaintScrollCorner(
+    WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const DocumentState& aDocumentState, const Colors& aColors,
+    const DPIRatio& aDpiRatio) {
+  return DoPaintDefaultScrollCorner(aWrData, aRect, aScrollbarKind, aFrame,
+                                    aStyle, aDocumentState, aColors, aDpiRatio);
+}
+
+nscolor ScrollbarDrawing::GetScrollbarButtonColor(nscolor aTrackColor,
+                                                  ElementState aStates) {
+  // See numbers in GetScrollbarArrowColor.
+  // This function is written based on ratios between values listed there.
+
+  bool isActive = aStates.HasState(ElementState::ACTIVE);
+  bool isHover = aStates.HasState(ElementState::HOVER);
+  if (!isActive && !isHover) {
+    return aTrackColor;
+  }
+  float luminance = RelativeLuminanceUtils::Compute(aTrackColor);
+  if (isActive) {
+    if (luminance >= 0.18f) {
+      luminance *= 0.134f;
+    } else {
+      luminance /= 0.134f;
+      luminance = std::min(luminance, 1.0f);
+    }
+  } else {
+    if (luminance >= 0.18f) {
+      luminance *= 0.805f;
+    } else {
+      luminance /= 0.805f;
+    }
+  }
+  return RelativeLuminanceUtils::Adjust(aTrackColor, luminance);
+}
+
+Maybe<nscolor> ScrollbarDrawing::GetScrollbarArrowColor(nscolor aButtonColor) {
+  // In Windows 10 scrollbar, there are several gray colors used:
+  //
+  // State  | Background (lum) | Arrow   | Contrast
+  // -------+------------------+---------+---------
+  // Normal | Gray 240 (87.1%) | Gray 96 |     5.5
+  // Hover  | Gray 218 (70.1%) | Black   |    15.0
+  // Active | Gray 96  (11.7%) | White   |     6.3
+  //
+  // Contrast value is computed based on the definition in
+  // https://www.w3.org/TR/WCAG20/#contrast-ratiodef
+  //
+  // This function is written based on these values.
+
+  if (NS_GET_A(aButtonColor) == 0) {
+    // If the button color is transparent, because of e.g.
+    // scrollbar-color: <something> transparent, then use
+    // the thumb color, which is expected to have enough
+    // contrast.
+    return Nothing();
+  }
+
+  float luminance = RelativeLuminanceUtils::Compute(aButtonColor);
+  // Color with luminance larger than 0.72 has contrast ratio over 4.6
+  // to color with luminance of gray 96, so this value is chosen for
+  // this range. It is the luminance of gray 221.
+  if (luminance >= 0.72) {
+    // ComputeRelativeLuminanceFromComponents(96). That function cannot
+    // be constexpr because of std::pow.
+    const float GRAY96_LUMINANCE = 0.117f;
+    return Some(RelativeLuminanceUtils::Adjust(aButtonColor, GRAY96_LUMINANCE));
+  }
+  // The contrast ratio of a color to black equals that to white when its
+  // luminance is around 0.18, with a contrast ratio ~4.6 to both sides,
+  // thus the value below. It's the lumanince of gray 118.
+  //
+  // TODO(emilio): Maybe the button alpha is not the best thing to use here and
+  // we should use the thumb alpha? It seems weird that the color of the arrow
+  // depends on the opacity of the scrollbar thumb...
+  if (luminance >= 0.18) {
+    return Some(NS_RGBA(0, 0, 0, NS_GET_A(aButtonColor)));
+  }
+  return Some(NS_RGBA(255, 255, 255, NS_GET_A(aButtonColor)));
+}
+
+std::pair<sRGBColor, sRGBColor> ScrollbarDrawing::ComputeScrollbarButtonColors(
+    nsIFrame* aFrame, StyleAppearance aAppearance, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    if (aElementState.HasAtLeastOneOfStates(ElementState::ACTIVE |
+                                            ElementState::HOVER)) {
+      return aColors.SystemPair(StyleSystemColor::Selecteditem,
+                                StyleSystemColor::Buttonface);
+    }
+    return aColors.SystemPair(StyleSystemColor::Window,
+                              StyleSystemColor::Windowtext);
+  }
+
+  auto trackColor =
+      ComputeScrollbarTrackColor(aFrame, aStyle, aDocumentState, aColors);
+  nscolor buttonColor =
+      GetScrollbarButtonColor(trackColor.ToABGR(), aElementState);
+  auto arrowColor =
+      GetScrollbarArrowColor(buttonColor)
+          .map(sRGBColor::FromABGR)
+          .valueOrFrom([&] {
+            return ComputeScrollbarThumbColor(aFrame, aStyle, aElementState,
+                                              aDocumentState, aColors);
+          });
+  return {sRGBColor::FromABGR(buttonColor), arrowColor};
+}
+
+bool ScrollbarDrawing::PaintScrollbarButton(
+    DrawTarget& aDrawTarget, StyleAppearance aAppearance,
+    const LayoutDeviceRect& aRect, ScrollbarKind aScrollbarKind,
+    nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio&) {
+  auto [buttonColor, arrowColor] = ComputeScrollbarButtonColors(
+      aFrame, aAppearance, aStyle, aElementState, aDocumentState, aColors);
+  aDrawTarget.FillRect(aRect.ToUnknownRect(),
+                       ColorPattern(ToDeviceColor(buttonColor)));
+
+  // Start with Up arrow.
+  float arrowPolygonX[] = {-4.0f, 0.0f, 4.0f, 4.0f, 0.0f, -4.0f};
+  float arrowPolygonY[] = {0.0f, -4.0f, 0.0f, 3.0f, -1.0f, 3.0f};
+
+  const float kPolygonSize = 17;
+
+  const int32_t arrowNumPoints = ArrayLength(arrowPolygonX);
+  switch (aAppearance) {
+    case StyleAppearance::ScrollbarbuttonUp:
+      break;
+    case StyleAppearance::ScrollbarbuttonDown:
+      for (int32_t i = 0; i < arrowNumPoints; i++) {
+        arrowPolygonY[i] *= -1;
+      }
+      break;
+    case StyleAppearance::ScrollbarbuttonLeft:
+      for (int32_t i = 0; i < arrowNumPoints; i++) {
+        float temp = arrowPolygonX[i];
+        arrowPolygonX[i] = arrowPolygonY[i];
+        arrowPolygonY[i] = temp;
+      }
+      break;
+    case StyleAppearance::ScrollbarbuttonRight:
+      for (int32_t i = 0; i < arrowNumPoints; i++) {
+        float temp = arrowPolygonX[i];
+        arrowPolygonX[i] = arrowPolygonY[i] * -1;
+        arrowPolygonY[i] = temp;
+      }
+      break;
+    default:
+      return false;
+  }
+  ThemeDrawing::PaintArrow(aDrawTarget, aRect, arrowPolygonX, arrowPolygonY,
+                           kPolygonSize, arrowNumPoints, arrowColor);
+  return true;
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/ScrollbarDrawing.h b/widget/ScrollbarDrawing.h
new file mode 100644
index 0000000000..656822aeed
--- /dev/null
+++ b/widget/ScrollbarDrawing.h
@@ -0,0 +1,172 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_ScrollbarDrawing_h
+#define mozilla_widget_ScrollbarDrawing_h
+
+#include "mozilla/dom/RustTypes.h"
+#include "mozilla/gfx/2D.h"
+#include "nsColor.h"
+#include "nsITheme.h"
+#include "ThemeColors.h"
+#include "ThemeDrawing.h"
+#include "Units.h"
+
+namespace mozilla::widget {
+
+class ScrollbarDrawing {
+ protected:
+  using DPIRatio = mozilla::CSSToLayoutDeviceScale;
+  using ElementState = dom::ElementState;
+  using DocumentState = dom::DocumentState;
+  using DrawTarget = mozilla::gfx::DrawTarget;
+  using sRGBColor = mozilla::gfx::sRGBColor;
+  using Colors = ThemeColors;
+  using Overlay = nsITheme::Overlay;
+  using WebRenderBackendData = mozilla::widget::WebRenderBackendData;
+
+  enum class Kind : uint8_t {
+    Android,
+    Cocoa,
+    Gtk,
+    Win10,
+    Win11,
+  };
+
+  explicit ScrollbarDrawing(Kind aKind) : mKind(aKind) {}
+
+ public:
+  virtual ~ScrollbarDrawing() = default;
+
+  enum class ScrollbarKind : uint8_t {
+    Horizontal,
+    VerticalLeft,
+    VerticalRight,
+  };
+
+  DPIRatio GetDPIRatioForScrollbarPart(const nsPresContext*);
+
+  static nsIFrame* GetParentScrollbarFrame(nsIFrame* aFrame);
+  static bool IsParentScrollbarRolledOver(nsIFrame* aFrame);
+  static bool IsParentScrollbarHoveredOrActive(nsIFrame* aFrame);
+
+  static bool IsScrollbarWidthThin(const ComputedStyle& aStyle);
+  static bool IsScrollbarWidthThin(nsIFrame* aFrame);
+
+  CSSIntCoord GetCSSScrollbarSize(StyleScrollbarWidth, Overlay) const;
+  LayoutDeviceIntCoord GetScrollbarSize(const nsPresContext*,
+                                        StyleScrollbarWidth, Overlay);
+  LayoutDeviceIntCoord GetScrollbarSize(const nsPresContext*, nsIFrame*);
+
+  virtual LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*,
+                                                   StyleAppearance aAppearance,
+                                                   nsIFrame* aFrame) = 0;
+  virtual Maybe<nsITheme::Transparency> GetScrollbarPartTransparency(
+      nsIFrame* aFrame, StyleAppearance aAppearance) {
+    return Nothing();
+  }
+
+  bool IsScrollbarTrackOpaque(nsIFrame*);
+  virtual sRGBColor ComputeScrollbarTrackColor(nsIFrame*, const ComputedStyle&,
+                                               const DocumentState&,
+                                               const Colors&);
+  virtual sRGBColor ComputeScrollbarThumbColor(nsIFrame*, const ComputedStyle&,
+                                               const ElementState&,
+                                               const DocumentState&,
+                                               const Colors&);
+
+  nscolor GetScrollbarButtonColor(nscolor aTrackColor, ElementState);
+  Maybe<nscolor> GetScrollbarArrowColor(nscolor aButtonColor);
+
+  // Returned colors are button, arrow.
+  virtual std::pair<sRGBColor, sRGBColor> ComputeScrollbarButtonColors(
+      nsIFrame*, StyleAppearance, const ComputedStyle&, const ElementState&,
+      const DocumentState&, const Colors&);
+
+  virtual bool PaintScrollbarButton(DrawTarget&, StyleAppearance,
+                                    const LayoutDeviceRect&, ScrollbarKind,
+                                    nsIFrame*, const ComputedStyle&,
+                                    const ElementState&, const DocumentState&,
+                                    const Colors&, const DPIRatio&);
+
+  virtual bool PaintScrollbarThumb(DrawTarget&, const LayoutDeviceRect&,
+                                   ScrollbarKind, nsIFrame*,
+                                   const ComputedStyle&, const ElementState&,
+                                   const DocumentState&, const Colors&,
+                                   const DPIRatio&) = 0;
+  virtual bool PaintScrollbarThumb(WebRenderBackendData&,
+                                   const LayoutDeviceRect&, ScrollbarKind,
+                                   nsIFrame*, const ComputedStyle&,
+                                   const ElementState&, const DocumentState&,
+                                   const Colors&, const DPIRatio&) = 0;
+
+  template <typename PaintBackendData>
+  bool DoPaintDefaultScrollbar(PaintBackendData&, const LayoutDeviceRect&,
+                               ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                               const ElementState&, const DocumentState&,
+                               const Colors&, const DPIRatio&);
+  bool PaintScrollbar(DrawTarget&, const LayoutDeviceRect&, ScrollbarKind,
+                      nsIFrame*, const ComputedStyle&, const ElementState&,
+                      const DocumentState&, const Colors&, const DPIRatio&);
+  bool PaintScrollbar(WebRenderBackendData&, const LayoutDeviceRect&,
+                      ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                      const ElementState&, const DocumentState&, const Colors&,
+                      const DPIRatio&);
+
+  virtual bool PaintScrollbarTrack(DrawTarget&, const LayoutDeviceRect&,
+                                   ScrollbarKind, nsIFrame*,
+                                   const ComputedStyle&, const DocumentState&,
+                                   const Colors&, const DPIRatio&) {
+    // Draw nothing by default. Subclasses can override this.
+    return true;
+  }
+  virtual bool PaintScrollbarTrack(WebRenderBackendData&,
+                                   const LayoutDeviceRect&, ScrollbarKind,
+                                   nsIFrame*, const ComputedStyle&,
+                                   const DocumentState&, const Colors&,
+                                   const DPIRatio&) {
+    // Draw nothing by default. Subclasses can override this.
+    return true;
+  }
+
+  template <typename PaintBackendData>
+  bool DoPaintDefaultScrollCorner(PaintBackendData&, const LayoutDeviceRect&,
+                                  ScrollbarKind, nsIFrame*,
+                                  const ComputedStyle&, const DocumentState&,
+                                  const Colors&, const DPIRatio&);
+  virtual bool PaintScrollCorner(DrawTarget&, const LayoutDeviceRect&,
+                                 ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                                 const DocumentState&, const Colors&,
+                                 const DPIRatio&);
+  virtual bool PaintScrollCorner(WebRenderBackendData&, const LayoutDeviceRect&,
+                                 ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                                 const DocumentState&, const Colors&,
+                                 const DPIRatio&);
+
+  virtual void RecomputeScrollbarParams() = 0;
+
+  virtual bool ShouldDrawScrollbarButtons() { return true; }
+
+ private:
+  // The scrollbar sizes for all our scrollbars. Indices are overlay or not,
+  // then thin or not. Should be configured via ConfigureScrollbarSize.
+  CSSIntCoord mScrollbarSize[2][2]{};
+
+ protected:
+  // For some kind of style differences a full virtual method is overkill, so we
+  // store the kind here so we can branch on it if necessary.
+  Kind mKind;
+
+  // Configures the scrollbar sizes based on a single size.
+  void ConfigureScrollbarSize(CSSIntCoord);
+
+  // Configures a particular scrollbar size.
+  void ConfigureScrollbarSize(StyleScrollbarWidth, Overlay, CSSIntCoord);
+};
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/ScrollbarDrawingAndroid.cpp b/widget/ScrollbarDrawingAndroid.cpp
new file mode 100644
index 0000000000..29ad917a91
--- /dev/null
+++ b/widget/ScrollbarDrawingAndroid.cpp
@@ -0,0 +1,84 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScrollbarDrawingAndroid.h"
+
+#include "nsIFrame.h"
+#include "nsNativeTheme.h"
+#include "mozilla/StaticPrefs_widget.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+LayoutDeviceIntSize ScrollbarDrawingAndroid::GetMinimumWidgetSize(
+    nsPresContext* aPresContext, StyleAppearance aAppearance,
+    nsIFrame* aFrame) {
+  MOZ_ASSERT(nsNativeTheme::IsWidgetScrollbarPart(aAppearance));
+  auto size =
+      GetScrollbarSize(aPresContext, StyleScrollbarWidth::Auto, Overlay::Yes);
+  return LayoutDeviceIntSize{size, size};
+}
+
+template <typename PaintBackendData>
+void ScrollbarDrawingAndroid::DoPaintScrollbarThumb(
+    PaintBackendData& aPaintData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  // TODO(emilio): Maybe do like macOS and draw a stroke?
+  const auto color = ComputeScrollbarThumbColor(aFrame, aStyle, aElementState,
+                                                aDocumentState, aColors);
+  const bool horizontal = aScrollbarKind == ScrollbarKind::Horizontal;
+
+  // Draw the thumb rect centered in the scrollbar.
+  LayoutDeviceRect thumbRect(aRect);
+  if (horizontal) {
+    thumbRect.height *= 0.5f;
+    thumbRect.y += thumbRect.height * 0.5f;
+  } else {
+    thumbRect.width *= 0.5f;
+    thumbRect.x += thumbRect.width * 0.5f;
+  }
+
+  const LayoutDeviceCoord radius =
+      (horizontal ? thumbRect.height : thumbRect.width) / 2.0f;
+  ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, thumbRect, color,
+                                           sRGBColor::White(0.0f), 0.0f,
+                                           radius / aDpiRatio, aDpiRatio);
+}
+
+bool ScrollbarDrawingAndroid::PaintScrollbarThumb(
+    DrawTarget& aDt, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  DoPaintScrollbarThumb(aDt, aRect, aScrollbarKind, aFrame, aStyle,
+                        aElementState, aDocumentState, aColors, aDpiRatio);
+  return true;
+}
+
+bool ScrollbarDrawingAndroid::PaintScrollbarThumb(
+    WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  DoPaintScrollbarThumb(aWrData, aRect, aScrollbarKind, aFrame, aStyle,
+                        aElementState, aDocumentState, aColors, aDpiRatio);
+  return true;
+}
+
+void ScrollbarDrawingAndroid::RecomputeScrollbarParams() {
+  uint32_t defaultSize = 6;
+  uint32_t overrideSize =
+      StaticPrefs::widget_non_native_theme_scrollbar_size_override();
+  if (overrideSize > 0) {
+    defaultSize = overrideSize;
+  }
+  ConfigureScrollbarSize(defaultSize);
+  // We make thin scrollbars as wide as auto ones because auto scrollbars on
+  // android are already thin enough.
+  ConfigureScrollbarSize(StyleScrollbarWidth::Thin, Overlay::Yes, defaultSize);
+  ConfigureScrollbarSize(StyleScrollbarWidth::Thin, Overlay::No, defaultSize);
+}
diff --git a/widget/ScrollbarDrawingAndroid.h b/widget/ScrollbarDrawingAndroid.h
new file mode 100644
index 0000000000..8986a6d70a
--- /dev/null
+++ b/widget/ScrollbarDrawingAndroid.h
@@ -0,0 +1,50 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_ScrollbarDrawingAndroid_h
+#define mozilla_widget_ScrollbarDrawingAndroid_h
+
+#include "nsITheme.h"
+#include "ScrollbarDrawing.h"
+
+namespace mozilla::widget {
+
+class ScrollbarDrawingAndroid final : public ScrollbarDrawing {
+ public:
+  ScrollbarDrawingAndroid() : ScrollbarDrawing(Kind::Android) {}
+  virtual ~ScrollbarDrawingAndroid() = default;
+
+  LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*,
+                                           StyleAppearance aAppearance,
+                                           nsIFrame* aFrame) override;
+
+  template <typename PaintBackendData>
+  void DoPaintScrollbarThumb(PaintBackendData&, const LayoutDeviceRect& aRect,
+                             ScrollbarKind, nsIFrame* aFrame,
+                             const ComputedStyle& aStyle,
+                             const ElementState& aElementState,
+                             const DocumentState& aDocumentState, const Colors&,
+                             const DPIRatio&);
+  bool PaintScrollbarThumb(DrawTarget&, const LayoutDeviceRect& aRect,
+                           ScrollbarKind, nsIFrame* aFrame,
+                           const ComputedStyle& aStyle,
+                           const ElementState& aElementState,
+                           const DocumentState& aDocumentState, const Colors&,
+                           const DPIRatio&) override;
+  bool PaintScrollbarThumb(WebRenderBackendData&, const LayoutDeviceRect& aRect,
+                           ScrollbarKind, nsIFrame* aFrame,
+                           const ComputedStyle& aStyle,
+                           const ElementState& aElementState,
+                           const DocumentState& aDocumentState, const Colors&,
+                           const DPIRatio&) override;
+
+  void RecomputeScrollbarParams() override;
+
+  bool ShouldDrawScrollbarButtons() override { return false; }
+};
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/ScrollbarDrawingCocoa.cpp b/widget/ScrollbarDrawingCocoa.cpp
new file mode 100644
index 0000000000..cf9f45d892
--- /dev/null
+++ b/widget/ScrollbarDrawingCocoa.cpp
@@ -0,0 +1,476 @@
+/* -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 2; -*- */
+/* vim: set sw=2 ts=8 et tw=80 : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScrollbarDrawingCocoa.h"
+
+#include "mozilla/gfx/Helpers.h"
+#include "mozilla/RelativeLuminanceUtils.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsContainerFrame.h"
+#include "nsAlgorithm.h"
+#include "nsIFrame.h"
+#include "nsLayoutUtils.h"
+#include "nsLookAndFeel.h"
+#include "nsNativeTheme.h"
+
+using namespace mozilla::gfx;
+namespace mozilla::widget {
+
+using ScrollbarKind = ScrollbarDrawing::ScrollbarKind;
+
+struct ColoredRect {
+  LayoutDeviceRect mRect;
+  nscolor mColor = 0;
+};
+
+// The caller can draw this rectangle with rounded corners as appropriate.
+struct ThumbRect {
+  LayoutDeviceRect mRect;
+  nscolor mFillColor = 0;
+  nscolor mStrokeColor = 0;
+  float mStrokeWidth = 0.0f;
+  float mStrokeOutset = 0.0f;
+};
+
+using ScrollbarTrackRects = Array<ColoredRect, 4>;
+using ScrollCornerRects = Array<ColoredRect, 7>;
+
+struct ScrollbarParams {
+  bool isOverlay = false;
+  bool isRolledOver = false;
+  bool isSmall = false;
+  bool isHorizontal = false;
+  bool isRtl = false;
+  bool isDark = false;
+  bool isCustom = false;
+  // Two colors only used when custom is true.
+  nscolor trackColor = NS_RGBA(0, 0, 0, 0);
+  nscolor faceColor = NS_RGBA(0, 0, 0, 0);
+};
+
+static ScrollbarParams ComputeScrollbarParams(nsIFrame* aFrame,
+                                              const ComputedStyle& aStyle,
+                                              const ThemeColors& aColors,
+                                              ScrollbarKind aScrollbarKind) {
+  ScrollbarParams params;
+  params.isOverlay =
+      nsLookAndFeel::GetInt(LookAndFeel::IntID::UseOverlayScrollbars) != 0;
+  params.isRolledOver = ScrollbarDrawing::IsParentScrollbarRolledOver(aFrame);
+  params.isSmall =
+      aStyle.StyleUIReset()->ScrollbarWidth() == StyleScrollbarWidth::Thin;
+  params.isRtl = aScrollbarKind == ScrollbarKind::VerticalLeft;
+  params.isHorizontal = aScrollbarKind == ScrollbarKind::Horizontal;
+  params.isDark = aColors.IsDark();
+
+  const nsStyleUI* ui = aStyle.StyleUI();
+  if (ui->HasCustomScrollbars()) {
+    const auto& colors = ui->mScrollbarColor.AsColors();
+    params.isCustom = true;
+    params.trackColor = colors.track.CalcColor(aStyle);
+    params.faceColor = colors.thumb.CalcColor(aStyle);
+  }
+
+  return params;
+}
+
+LayoutDeviceIntSize ScrollbarDrawingCocoa::GetMinimumWidgetSize(
+    nsPresContext* aPresContext, StyleAppearance aAppearance,
+    nsIFrame* aFrame) {
+  MOZ_ASSERT(nsNativeTheme::IsWidgetScrollbarPart(aAppearance));
+
+  auto minSize = [&]() -> CSSIntSize {
+    switch (aAppearance) {
+      case StyleAppearance::ScrollbarthumbHorizontal:
+        return {26, 0};
+      case StyleAppearance::ScrollbarthumbVertical:
+        return {0, 26};
+      case StyleAppearance::ScrollbarVertical:
+      case StyleAppearance::ScrollbarHorizontal:
+      case StyleAppearance::ScrollbartrackVertical:
+      case StyleAppearance::ScrollbartrackHorizontal: {
+        ComputedStyle* style = nsLayoutUtils::StyleForScrollbar(aFrame);
+        auto scrollbarWidth = style->StyleUIReset()->ScrollbarWidth();
+        auto size = GetCSSScrollbarSize(
+            scrollbarWidth, Overlay(aPresContext->UseOverlayScrollbars()));
+        return {size, size};
+      }
+      case StyleAppearance::ScrollbarbuttonUp:
+      case StyleAppearance::ScrollbarbuttonDown:
+        return {15, 16};
+      case StyleAppearance::ScrollbarbuttonLeft:
+      case StyleAppearance::ScrollbarbuttonRight:
+        return {16, 15};
+      default:
+        return {};
+    }
+  }();
+
+  auto dpi = GetDPIRatioForScrollbarPart(aPresContext);
+  return LayoutDeviceIntSize::Round(CSSSize(minSize) * dpi);
+}
+
+static ThumbRect GetThumbRect(const LayoutDeviceRect& aRect,
+                              const ScrollbarParams& aParams, float aScale) {
+  // Compute the thumb thickness. This varies based on aParams.small,
+  // aParams.overlay and aParams.rolledOver. non-overlay: 6 / 8, overlay
+  // non-hovered: 5 / 7, overlay hovered: 9 / 11
+  float thickness = aParams.isSmall ? 6.0f : 8.0f;
+  if (aParams.isOverlay) {
+    thickness -= 1.0f;
+    if (aParams.isRolledOver) {
+      thickness += 4.0f;
+    }
+  }
+  thickness *= aScale;
+
+  // Compute the thumb rect.
+  const float outerSpacing =
+      ((aParams.isOverlay || aParams.isSmall) ? 1.0f : 2.0f) * aScale;
+  LayoutDeviceRect thumbRect = aRect;
+  thumbRect.Deflate(1.0f * aScale);
+  if (aParams.isHorizontal) {
+    float bottomEdge = thumbRect.YMost() - outerSpacing;
+    thumbRect.SetBoxY(bottomEdge - thickness, bottomEdge);
+  } else {
+    if (aParams.isRtl) {
+      float leftEdge = thumbRect.X() + outerSpacing;
+      thumbRect.SetBoxX(leftEdge, leftEdge + thickness);
+    } else {
+      float rightEdge = thumbRect.XMost() - outerSpacing;
+      thumbRect.SetBoxX(rightEdge - thickness, rightEdge);
+    }
+  }
+
+  // Compute the thumb fill color.
+  nscolor faceColor;
+  if (aParams.isCustom) {
+    faceColor = aParams.faceColor;
+  } else {
+    if (aParams.isOverlay) {
+      faceColor =
+          aParams.isDark ? NS_RGBA(255, 255, 255, 128) : NS_RGBA(0, 0, 0, 128);
+    } else if (aParams.isDark) {
+      faceColor = aParams.isRolledOver ? NS_RGBA(158, 158, 158, 255)
+                                       : NS_RGBA(117, 117, 117, 255);
+    } else {
+      faceColor = aParams.isRolledOver ? NS_RGBA(125, 125, 125, 255)
+                                       : NS_RGBA(194, 194, 194, 255);
+    }
+  }
+
+  nscolor strokeColor = 0;
+  float strokeOutset = 0.0f;
+  float strokeWidth = 0.0f;
+
+  // Overlay scrollbars have an additional stroke around the fill.
+  if (aParams.isOverlay) {
+    // For the default alpha of 128 we want to end up with 48 in the outline.
+    constexpr float kAlphaScaling = 48.0f / 128.0f;
+    const uint8_t strokeAlpha =
+        uint8_t(clamped(NS_GET_A(faceColor) * kAlphaScaling, 0.0f, 48.0f));
+    if (strokeAlpha) {
+      strokeOutset = (aParams.isDark ? 0.3f : 0.5f) * aScale;
+      strokeWidth = (aParams.isDark ? 0.6f : 0.8f) * aScale;
+
+      strokeColor = aParams.isDark ? NS_RGBA(0, 0, 0, strokeAlpha)
+                                   : NS_RGBA(255, 255, 255, strokeAlpha);
+    }
+  }
+
+  return {thumbRect, faceColor, strokeColor, strokeWidth, strokeOutset};
+}
+
+struct ScrollbarTrackDecorationColors {
+  nscolor mInnerColor = 0;
+  nscolor mShadowColor = 0;
+  nscolor mOuterColor = 0;
+};
+
+static ScrollbarTrackDecorationColors ComputeScrollbarTrackDecorationColors(
+    nscolor aTrackColor) {
+  ScrollbarTrackDecorationColors result;
+  float luminance = RelativeLuminanceUtils::Compute(aTrackColor);
+  if (luminance >= 0.5f) {
+    result.mInnerColor =
+        RelativeLuminanceUtils::Adjust(aTrackColor, luminance * 0.836f);
+    result.mShadowColor =
+        RelativeLuminanceUtils::Adjust(aTrackColor, luminance * 0.982f);
+    result.mOuterColor =
+        RelativeLuminanceUtils::Adjust(aTrackColor, luminance * 0.886f);
+  } else {
+    result.mInnerColor =
+        RelativeLuminanceUtils::Adjust(aTrackColor, luminance * 1.196f);
+    result.mShadowColor =
+        RelativeLuminanceUtils::Adjust(aTrackColor, luminance * 1.018f);
+    result.mOuterColor =
+        RelativeLuminanceUtils::Adjust(aTrackColor, luminance * 1.129f);
+  }
+  return result;
+}
+
+static bool GetScrollbarTrackRects(const LayoutDeviceRect& aRect,
+                                   const ScrollbarParams& aParams, float aScale,
+                                   ScrollbarTrackRects& aRects) {
+  if (aParams.isOverlay && !aParams.isRolledOver) {
+    // Non-hovered overlay scrollbars don't have a track. Draw nothing.
+    return false;
+  }
+
+  nscolor trackColor;
+  if (aParams.isCustom) {
+    trackColor = aParams.trackColor;
+  } else {
+    if (aParams.isOverlay) {
+      trackColor = aParams.isDark ? NS_RGBA(201, 201, 201, 38)
+                                  : NS_RGBA(250, 250, 250, 191);
+    } else {
+      trackColor = aParams.isDark ? NS_RGBA(46, 46, 46, 255)
+                                  : NS_RGBA(250, 250, 250, 255);
+    }
+  }
+
+  float thickness = aParams.isHorizontal ? aRect.height : aRect.width;
+
+  // The scrollbar track is drawn as multiple non-overlapping segments, which
+  // make up lines of different widths and with slightly different shading.
+  ScrollbarTrackDecorationColors colors =
+      ComputeScrollbarTrackDecorationColors(trackColor);
+  struct {
+    nscolor color;
+    float thickness;
+  } segments[] = {
+      {colors.mInnerColor, 1.0f * aScale},
+      {colors.mShadowColor, 1.0f * aScale},
+      {trackColor, thickness - 3.0f * aScale},
+      {colors.mOuterColor, 1.0f * aScale},
+  };
+
+  // Iterate over the segments "from inside to outside" and fill each segment.
+  // For horizontal scrollbars, iterate top to bottom.
+  // For vertical scrollbars, iterate left to right or right to left based on
+  // aParams.isRtl.
+  auto current = aRects.begin();
+  float accumulatedThickness = 0.0f;
+  for (const auto& segment : segments) {
+    LayoutDeviceRect segmentRect = aRect;
+    float startThickness = accumulatedThickness;
+    float endThickness = startThickness + segment.thickness;
+    if (aParams.isHorizontal) {
+      segmentRect.SetBoxY(aRect.Y() + startThickness, aRect.Y() + endThickness);
+    } else {
+      if (aParams.isRtl) {
+        segmentRect.SetBoxX(aRect.XMost() - endThickness,
+                            aRect.XMost() - startThickness);
+      } else {
+        segmentRect.SetBoxX(aRect.X() + startThickness,
+                            aRect.X() + endThickness);
+      }
+    }
+    accumulatedThickness = endThickness;
+    *current++ = {segmentRect, segment.color};
+  }
+
+  return true;
+}
+
+static bool GetScrollCornerRects(const LayoutDeviceRect& aRect,
+                                 const ScrollbarParams& aParams, float aScale,
+                                 ScrollCornerRects& aRects) {
+  if (aParams.isOverlay && !aParams.isRolledOver) {
+    // Non-hovered overlay scrollbars don't have a corner. Draw nothing.
+    return false;
+  }
+
+  // Draw the following scroll corner.
+  //
+  //        Output:                      Rectangles:
+  // +---+---+----------+---+     +---+---+----------+---+
+  // | I | S | T ...  T | O |     | I | S | T ...  T | O |
+  // +---+   |          |   |     +---+---+          |   |
+  // | S   S | T ...  T |   |     | S   S | T ...  T | . |
+  // +-------+          | . |     +-------+----------+ . |
+  // | T      ...     T | . |     | T      ...     T | . |
+  // | .              . | . |     | .              . |   |
+  // | T      ...     T |   |     | T      ...     T | O |
+  // +------------------+   |     +------------------+---+
+  // | O       ...        O |     | O       ...        O |
+  // +----------------------+     +----------------------+
+
+  float width = aRect.width;
+  float height = aRect.height;
+  nscolor trackColor;
+  if (aParams.isCustom) {
+    trackColor = aParams.trackColor;
+  } else {
+    trackColor =
+        aParams.isDark ? NS_RGBA(46, 46, 46, 255) : NS_RGBA(250, 250, 250, 255);
+  }
+  ScrollbarTrackDecorationColors colors =
+      ComputeScrollbarTrackDecorationColors(trackColor);
+  struct {
+    nscolor color;
+    LayoutDeviceRect relativeRect;
+  } pieces[] = {
+      {colors.mInnerColor, {0.0f, 0.0f, 1.0f * aScale, 1.0f * aScale}},
+      {colors.mShadowColor,
+       {1.0f * aScale, 0.0f, 1.0f * aScale, 1.0f * aScale}},
+      {colors.mShadowColor,
+       {0.0f, 1.0f * aScale, 2.0f * aScale, 1.0f * aScale}},
+      {trackColor, {2.0f * aScale, 0.0f, width - 3.0f * aScale, 2.0f * aScale}},
+      {trackColor,
+       {0.0f, 2.0f * aScale, width - 1.0f * aScale, height - 3.0f * aScale}},
+      {colors.mOuterColor,
+       {width - 1.0f * aScale, 0.0f, 1.0f * aScale, height - 1.0f * aScale}},
+      {colors.mOuterColor,
+       {0.0f, height - 1.0f * aScale, width, 1.0f * aScale}},
+  };
+
+  auto current = aRects.begin();
+  for (const auto& piece : pieces) {
+    LayoutDeviceRect pieceRect = piece.relativeRect + aRect.TopLeft();
+    if (aParams.isRtl) {
+      pieceRect.x = aRect.XMost() - piece.relativeRect.XMost();
+    }
+    *current++ = {pieceRect, piece.color};
+  }
+  return true;
+}
+
+template <typename PaintBackendData>
+void ScrollbarDrawingCocoa::DoPaintScrollbarThumb(
+    PaintBackendData& aPaintData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  ScrollbarParams params =
+      ComputeScrollbarParams(aFrame, aStyle, aColors, aScrollbarKind);
+  auto thumb = GetThumbRect(aRect, params, aDpiRatio.scale);
+  LayoutDeviceCoord radius =
+      (params.isHorizontal ? thumb.mRect.Height() : thumb.mRect.Width()) / 2.0f;
+  ThemeDrawing::PaintRoundedRectWithRadius(
+      aPaintData, thumb.mRect, thumb.mRect,
+      sRGBColor::FromABGR(thumb.mFillColor), sRGBColor::White(0.0f), 0.0f,
+      radius / aDpiRatio, aDpiRatio);
+  if (!thumb.mStrokeColor) {
+    return;
+  }
+
+  // Paint the stroke if needed.
+  auto strokeRect = thumb.mRect;
+  strokeRect.Inflate(thumb.mStrokeOutset + thumb.mStrokeWidth);
+  radius =
+      (params.isHorizontal ? strokeRect.Height() : strokeRect.Width()) / 2.0f;
+  ThemeDrawing::PaintRoundedRectWithRadius(
+      aPaintData, strokeRect, sRGBColor::White(0.0f),
+      sRGBColor::FromABGR(thumb.mStrokeColor), thumb.mStrokeWidth,
+      radius / aDpiRatio, aDpiRatio);
+}
+
+bool ScrollbarDrawingCocoa::PaintScrollbarThumb(
+    DrawTarget& aDt, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  DoPaintScrollbarThumb(aDt, aRect, aScrollbarKind, aFrame, aStyle,
+                        aElementState, aDocumentState, aColors, aDpiRatio);
+  return true;
+}
+
+bool ScrollbarDrawingCocoa::PaintScrollbarThumb(
+    WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  DoPaintScrollbarThumb(aWrData, aRect, aScrollbarKind, aFrame, aStyle,
+                        aElementState, aDocumentState, aColors, aDpiRatio);
+  return true;
+}
+
+template <typename PaintBackendData>
+void ScrollbarDrawingCocoa::DoPaintScrollbarTrack(
+    PaintBackendData& aPaintData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const DocumentState& aDocumentState, const Colors& aColors,
+    const DPIRatio& aDpiRatio) {
+  ScrollbarParams params =
+      ComputeScrollbarParams(aFrame, aStyle, aColors, aScrollbarKind);
+  ScrollbarTrackRects rects;
+  if (GetScrollbarTrackRects(aRect, params, aDpiRatio.scale, rects)) {
+    for (const auto& rect : rects) {
+      ThemeDrawing::FillRect(aPaintData, rect.mRect,
+                             sRGBColor::FromABGR(rect.mColor));
+    }
+  }
+}
+
+bool ScrollbarDrawingCocoa::PaintScrollbarTrack(
+    DrawTarget& aDt, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const DocumentState& aDocumentState, const Colors& aColors,
+    const DPIRatio& aDpiRatio) {
+  DoPaintScrollbarTrack(aDt, aRect, aScrollbarKind, aFrame, aStyle,
+                        aDocumentState, aColors, aDpiRatio);
+  return true;
+}
+
+bool ScrollbarDrawingCocoa::PaintScrollbarTrack(
+    WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const DocumentState& aDocumentState, const Colors& aColors,
+    const DPIRatio& aDpiRatio) {
+  DoPaintScrollbarTrack(aWrData, aRect, aScrollbarKind, aFrame, aStyle,
+                        aDocumentState, aColors, aDpiRatio);
+  return true;
+}
+
+template <typename PaintBackendData>
+void ScrollbarDrawingCocoa::DoPaintScrollCorner(
+    PaintBackendData& aPaintData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const DocumentState& aDocumentState, const Colors& aColors,
+    const DPIRatio& aDpiRatio) {
+  ScrollbarParams params =
+      ComputeScrollbarParams(aFrame, aStyle, aColors, aScrollbarKind);
+  ScrollCornerRects rects;
+  if (GetScrollCornerRects(aRect, params, aDpiRatio.scale, rects)) {
+    for (const auto& rect : rects) {
+      ThemeDrawing::FillRect(aPaintData, rect.mRect,
+                             sRGBColor::FromABGR(rect.mColor));
+    }
+  }
+}
+
+bool ScrollbarDrawingCocoa::PaintScrollCorner(
+    DrawTarget& aDt, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const DocumentState& aDocumentState, const Colors& aColors,
+    const DPIRatio& aDpiRatio) {
+  DoPaintScrollCorner(aDt, aRect, aScrollbarKind, aFrame, aStyle,
+                      aDocumentState, aColors, aDpiRatio);
+  return true;
+}
+
+bool ScrollbarDrawingCocoa::PaintScrollCorner(
+    WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const DocumentState& aDocumentState, const Colors& aColors,
+    const DPIRatio& aDpiRatio) {
+  DoPaintScrollCorner(aWrData, aRect, aScrollbarKind, aFrame, aStyle,
+                      aDocumentState, aColors, aDpiRatio);
+  return true;
+}
+
+void ScrollbarDrawingCocoa::RecomputeScrollbarParams() {
+  // FIXME(emilio): This doesn't respect the
+  // StaticPrefs::widget_non_native_theme_scrollbar_size_override() pref;
+  ConfigureScrollbarSize(15);  // Just in case, for future-proofing
+  ConfigureScrollbarSize(StyleScrollbarWidth::Auto, Overlay::No, 15);
+  ConfigureScrollbarSize(StyleScrollbarWidth::Thin, Overlay::No, 11);
+  ConfigureScrollbarSize(StyleScrollbarWidth::Auto, Overlay::Yes, 16);
+  ConfigureScrollbarSize(StyleScrollbarWidth::Thin, Overlay::Yes, 14);
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/ScrollbarDrawingCocoa.h b/widget/ScrollbarDrawingCocoa.h
new file mode 100644
index 0000000000..840da6c232
--- /dev/null
+++ b/widget/ScrollbarDrawingCocoa.h
@@ -0,0 +1,76 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_ScrollbarDrawingCocoa_h
+#define mozilla_widget_ScrollbarDrawingCocoa_h
+
+#include "ScrollbarDrawing.h"
+
+#include "mozilla/Array.h"
+
+namespace mozilla::widget {
+
+class ScrollbarDrawingCocoa final : public ScrollbarDrawing {
+ public:
+  ScrollbarDrawingCocoa() : ScrollbarDrawing(Kind::Cocoa) {}
+  virtual ~ScrollbarDrawingCocoa() = default;
+
+  LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*,
+                                           StyleAppearance aAppearance,
+                                           nsIFrame* aFrame) override;
+
+  static CSSIntCoord GetScrollbarSize(StyleScrollbarWidth, bool aOverlay);
+
+  template <typename PaintBackendData>
+  void DoPaintScrollbarThumb(PaintBackendData&, const LayoutDeviceRect& aRect,
+                             ScrollbarKind, nsIFrame* aFrame,
+                             const ComputedStyle& aStyle, const ElementState&,
+                             const DocumentState&, const Colors&,
+                             const DPIRatio&);
+  bool PaintScrollbarThumb(DrawTarget&, const LayoutDeviceRect&, ScrollbarKind,
+                           nsIFrame*, const ComputedStyle&, const ElementState&,
+                           const DocumentState&, const Colors&,
+                           const DPIRatio&) override;
+  bool PaintScrollbarThumb(WebRenderBackendData&, const LayoutDeviceRect&,
+                           ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                           const ElementState&, const DocumentState&,
+                           const Colors&, const DPIRatio&) override;
+
+  template <typename PaintBackendData>
+  void DoPaintScrollbarTrack(PaintBackendData&, const LayoutDeviceRect&,
+                             ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                             const DocumentState&, const Colors&,
+                             const DPIRatio&);
+  bool PaintScrollbarTrack(DrawTarget&, const LayoutDeviceRect& aRect,
+                           ScrollbarKind, nsIFrame* aFrame,
+                           const ComputedStyle& aStyle, const DocumentState&,
+                           const Colors&, const DPIRatio&) override;
+  bool PaintScrollbarTrack(WebRenderBackendData&, const LayoutDeviceRect& aRect,
+                           ScrollbarKind, nsIFrame* aFrame,
+                           const ComputedStyle& aStyle, const DocumentState&,
+                           const Colors&, const DPIRatio&) override;
+
+  template <typename PaintBackendData>
+  void DoPaintScrollCorner(PaintBackendData&, const LayoutDeviceRect&,
+                           ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                           const DocumentState&, const Colors&,
+                           const DPIRatio&);
+  bool PaintScrollCorner(DrawTarget&, const LayoutDeviceRect&, ScrollbarKind,
+                         nsIFrame*, const ComputedStyle&, const DocumentState&,
+                         const Colors&, const DPIRatio&) override;
+  bool PaintScrollCorner(WebRenderBackendData&, const LayoutDeviceRect&,
+                         ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                         const DocumentState&, const Colors&,
+                         const DPIRatio&) override;
+
+  void RecomputeScrollbarParams() override;
+
+  bool ShouldDrawScrollbarButtons() override { return false; }
+};
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/ScrollbarDrawingGTK.cpp b/widget/ScrollbarDrawingGTK.cpp
new file mode 100644
index 0000000000..3e0cad9179
--- /dev/null
+++ b/widget/ScrollbarDrawingGTK.cpp
@@ -0,0 +1,133 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScrollbarDrawingGTK.h"
+
+#include "mozilla/gfx/Helpers.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsLayoutUtils.h"
+#include "nsNativeTheme.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using namespace mozilla::widget;
+
+LayoutDeviceIntSize ScrollbarDrawingGTK::GetMinimumWidgetSize(
+    nsPresContext* aPresContext, StyleAppearance aAppearance,
+    nsIFrame* aFrame) {
+  MOZ_ASSERT(nsNativeTheme::IsWidgetScrollbarPart(aAppearance));
+  auto scrollbarSize = GetScrollbarSize(aPresContext, aFrame);
+  LayoutDeviceIntSize size{scrollbarSize, scrollbarSize};
+  if (aAppearance == StyleAppearance::ScrollbarHorizontal ||
+      aAppearance == StyleAppearance::ScrollbarVertical ||
+      aAppearance == StyleAppearance::ScrollbarthumbHorizontal ||
+      aAppearance == StyleAppearance::ScrollbarthumbVertical) {
+    CSSCoord thumbSize(
+        StaticPrefs::widget_non_native_theme_gtk_scrollbar_thumb_cross_size());
+    const bool isVertical =
+        aAppearance == StyleAppearance::ScrollbarVertical ||
+        aAppearance == StyleAppearance::ScrollbarthumbVertical;
+    auto dpi = GetDPIRatioForScrollbarPart(aPresContext);
+    if (isVertical) {
+      size.height = thumbSize * dpi;
+    } else {
+      size.width = thumbSize * dpi;
+    }
+  }
+  return size;
+}
+
+Maybe<nsITheme::Transparency> ScrollbarDrawingGTK::GetScrollbarPartTransparency(
+    nsIFrame* aFrame, StyleAppearance aAppearance) {
+  if (!aFrame->PresContext()->UseOverlayScrollbars() &&
+      (aAppearance == StyleAppearance::ScrollbarVertical ||
+       aAppearance == StyleAppearance::ScrollbarHorizontal) &&
+      IsScrollbarTrackOpaque(aFrame)) {
+    return Some(nsITheme::eOpaque);
+  }
+
+  return Nothing();
+}
+
+template <typename PaintBackendData>
+bool ScrollbarDrawingGTK::DoPaintScrollbarThumb(
+    PaintBackendData& aPaintData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  sRGBColor thumbColor = ComputeScrollbarThumbColor(
+      aFrame, aStyle, aElementState, aDocumentState, aColors);
+
+  LayoutDeviceRect thumbRect(aRect);
+
+  const bool horizontal = aScrollbarKind == ScrollbarKind::Horizontal;
+  if (aFrame->PresContext()->UseOverlayScrollbars() &&
+      !ScrollbarDrawing::IsParentScrollbarHoveredOrActive(aFrame)) {
+    if (horizontal) {
+      thumbRect.height *= 0.5;
+      thumbRect.y += thumbRect.height;
+    } else {
+      thumbRect.width *= 0.5;
+      if (aScrollbarKind == ScrollbarKind::VerticalRight) {
+        thumbRect.x += thumbRect.width;
+      }
+    }
+  }
+
+  {
+    float factor = std::max(
+        0.0f,
+        1.0f - StaticPrefs::widget_non_native_theme_gtk_scrollbar_thumb_size());
+    thumbRect.Deflate((horizontal ? thumbRect.height : thumbRect.width) *
+                      factor);
+  }
+
+  LayoutDeviceCoord radius =
+      StaticPrefs::widget_non_native_theme_gtk_scrollbar_round_thumb()
+          ? (horizontal ? thumbRect.height : thumbRect.width) / 2.0f
+          : 0.0f;
+
+  ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, thumbRect, thumbColor,
+                                           sRGBColor(), 0, radius / aDpiRatio,
+                                           aDpiRatio);
+  return true;
+}
+
+bool ScrollbarDrawingGTK::PaintScrollbarThumb(
+    DrawTarget& aDrawTarget, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  return DoPaintScrollbarThumb(aDrawTarget, aRect, aScrollbarKind, aFrame,
+                               aStyle, aElementState, aDocumentState, aColors,
+                               aDpiRatio);
+}
+
+bool ScrollbarDrawingGTK::PaintScrollbarThumb(
+    WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  return DoPaintScrollbarThumb(aWrData, aRect, aScrollbarKind, aFrame, aStyle,
+                               aElementState, aDocumentState, aColors,
+                               aDpiRatio);
+}
+
+bool ScrollbarDrawingGTK::ShouldDrawScrollbarButtons() {
+  if (StaticPrefs::widget_non_native_theme_enabled()) {
+    return StaticPrefs::widget_non_native_theme_gtk_scrollbar_allow_buttons();
+  }
+  return true;
+}
+
+void ScrollbarDrawingGTK::RecomputeScrollbarParams() {
+  uint32_t defaultSize = 12;
+  uint32_t overrideSize =
+      StaticPrefs::widget_non_native_theme_scrollbar_size_override();
+  if (overrideSize > 0) {
+    defaultSize = overrideSize;
+  }
+  ConfigureScrollbarSize(defaultSize);
+}
diff --git a/widget/ScrollbarDrawingGTK.h b/widget/ScrollbarDrawingGTK.h
new file mode 100644
index 0000000000..162997e127
--- /dev/null
+++ b/widget/ScrollbarDrawingGTK.h
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_ScrollbarDrawingGTK_h
+#define mozilla_widget_ScrollbarDrawingGTK_h
+
+#include "nsITheme.h"
+#include "nsNativeTheme.h"
+#include "ScrollbarDrawing.h"
+
+namespace mozilla::widget {
+
+class ScrollbarDrawingGTK final : public ScrollbarDrawing {
+ public:
+  ScrollbarDrawingGTK() : ScrollbarDrawing(Kind::Gtk) {}
+  virtual ~ScrollbarDrawingGTK() = default;
+
+  LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*,
+                                           StyleAppearance aAppearance,
+                                           nsIFrame* aFrame) override;
+
+  Maybe<nsITheme::Transparency> GetScrollbarPartTransparency(
+      nsIFrame* aFrame, StyleAppearance aAppearance) override;
+
+  template <typename PaintBackendData>
+  bool DoPaintScrollbarThumb(PaintBackendData&, const LayoutDeviceRect&,
+                             ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                             const ElementState& aElementState,
+                             const DocumentState& aDocumentState, const Colors&,
+                             const DPIRatio&);
+  bool PaintScrollbarThumb(DrawTarget&, const LayoutDeviceRect&, ScrollbarKind,
+                           nsIFrame*, const ComputedStyle& aStyle,
+                           const ElementState& aElementState,
+                           const DocumentState& aDocumentState, const Colors&,
+                           const DPIRatio&) override;
+  bool PaintScrollbarThumb(WebRenderBackendData&, const LayoutDeviceRect&,
+                           ScrollbarKind, nsIFrame*,
+                           const ComputedStyle& aStyle,
+                           const ElementState& aElementState,
+                           const DocumentState& aDocumentState, const Colors&,
+                           const DPIRatio&) override;
+
+  void RecomputeScrollbarParams() override;
+
+  bool ShouldDrawScrollbarButtons() override;
+};
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/ScrollbarDrawingWin.cpp b/widget/ScrollbarDrawingWin.cpp
new file mode 100644
index 0000000000..c2d85ae671
--- /dev/null
+++ b/widget/ScrollbarDrawingWin.cpp
@@ -0,0 +1,173 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScrollbarDrawingWin.h"
+
+#include "mozilla/gfx/Helpers.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsLayoutUtils.h"
+#include "Theme.h"
+#include "nsNativeTheme.h"
+
+namespace mozilla::widget {
+
+LayoutDeviceIntSize ScrollbarDrawingWin::GetMinimumWidgetSize(
+    nsPresContext* aPresContext, StyleAppearance aAppearance,
+    nsIFrame* aFrame) {
+  MOZ_ASSERT(nsNativeTheme::IsWidgetScrollbarPart(aAppearance));
+
+  switch (aAppearance) {
+    case StyleAppearance::ScrollbarbuttonUp:
+    case StyleAppearance::ScrollbarbuttonDown:
+    case StyleAppearance::ScrollbarbuttonLeft:
+    case StyleAppearance::ScrollbarbuttonRight:
+      // For scrollbar-width:thin, we don't display the buttons.
+      if (IsScrollbarWidthThin(aFrame)) {
+        return LayoutDeviceIntSize{};
+      }
+      [[fallthrough]];
+    case StyleAppearance::ScrollbarVertical:
+    case StyleAppearance::ScrollbarHorizontal:
+    case StyleAppearance::ScrollbarthumbVertical:
+    case StyleAppearance::ScrollbarthumbHorizontal: {
+      // TODO: for short scrollbars it could be nice if the thumb could shrink
+      // under this size.
+      auto relevantSize = GetScrollbarSize(aPresContext, aFrame);
+      const bool isHorizontal =
+          aAppearance == StyleAppearance::ScrollbarHorizontal ||
+          aAppearance == StyleAppearance::ScrollbarthumbHorizontal ||
+          aAppearance == StyleAppearance::ScrollbarbuttonLeft ||
+          aAppearance == StyleAppearance::ScrollbarbuttonRight;
+      auto size = LayoutDeviceIntSize{relevantSize, relevantSize};
+      if (aAppearance == StyleAppearance::ScrollbarHorizontal ||
+          aAppearance == StyleAppearance::ScrollbarVertical) {
+        // Always reserve some space in the right direction. Historically we've
+        // reserved 2 times the size in the other axis (for the buttons).
+        // We do this even when painting thin scrollbars just for consistency,
+        // though there just one would probably do there.
+        if (isHorizontal) {
+          size.width *= 2;
+        } else {
+          size.height *= 2;
+        }
+      }
+      return size;
+    }
+    default:
+      return LayoutDeviceIntSize{};
+  }
+}
+
+// Returns the style for custom scrollbar if the scrollbar part frame should
+// use the custom drawing path, nullptr otherwise.
+const ComputedStyle* GetCustomScrollbarStyle(nsIFrame* aFrame) {
+  const ComputedStyle* style = nsLayoutUtils::StyleForScrollbar(aFrame);
+  if (style->StyleUI()->HasCustomScrollbars() ||
+      ScrollbarDrawing::IsScrollbarWidthThin(*style)) {
+    return style;
+  }
+  bool useDarkScrollbar = !StaticPrefs::widget_disable_dark_scrollbar() &&
+                          nsNativeTheme::IsDarkBackgroundForScrollbar(aFrame);
+  if (useDarkScrollbar) {
+    return style;
+  }
+  return nullptr;
+}
+
+Maybe<nsITheme::Transparency> ScrollbarDrawingWin::GetScrollbarPartTransparency(
+    nsIFrame* aFrame, StyleAppearance aAppearance) {
+  if (nsNativeTheme::IsWidgetScrollbarPart(aAppearance)) {
+    if (const ComputedStyle* style = GetCustomScrollbarStyle(aFrame)) {
+      auto* ui = style->StyleUI();
+      if (ui->mScrollbarColor.IsAuto() ||
+          ui->mScrollbarColor.AsColors().track.MaybeTransparent()) {
+        return Some(nsITheme::eTransparent);
+      }
+      // These widgets may be thinner than the track, so we need to return
+      // transparent for them to make the track visible.
+      switch (aAppearance) {
+        case StyleAppearance::ScrollbarthumbHorizontal:
+        case StyleAppearance::ScrollbarthumbVertical:
+        case StyleAppearance::ScrollbarbuttonUp:
+        case StyleAppearance::ScrollbarbuttonDown:
+        case StyleAppearance::ScrollbarbuttonLeft:
+        case StyleAppearance::ScrollbarbuttonRight:
+          return Some(nsITheme::eTransparent);
+        default:
+          break;
+      }
+    }
+    if (aFrame->PresContext()->UseOverlayScrollbars()) {
+      return Some(nsITheme::eTransparent);
+    }
+  }
+
+  switch (aAppearance) {
+    case StyleAppearance::ScrollbarHorizontal:
+    case StyleAppearance::ScrollbarVertical:
+    case StyleAppearance::Scrollcorner:
+      // Knowing that scrollbars and statusbars are opaque improves
+      // performance, because we create layers for them. This better be
+      // true across all Windows themes! If it's not true, we should
+      // paint an opaque background for them to make it true!
+      // TODO(emilio): Unclear how much this optimization matters in practice
+      // now we're in a WR-only world.
+      return Some(nsITheme::eOpaque);
+    default:
+      break;
+  }
+
+  return Nothing();
+}
+
+template <typename PaintBackendData>
+bool ScrollbarDrawingWin::DoPaintScrollbarThumb(
+    PaintBackendData& aPaintData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  sRGBColor thumbColor = ComputeScrollbarThumbColor(
+      aFrame, aStyle, aElementState, aDocumentState, aColors);
+  ThemeDrawing::FillRect(aPaintData, aRect, thumbColor);
+  return true;
+}
+
+bool ScrollbarDrawingWin::PaintScrollbarThumb(
+    DrawTarget& aDrawTarget, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  return DoPaintScrollbarThumb(aDrawTarget, aRect, aScrollbarKind, aFrame,
+                               aStyle, aElementState, aDocumentState, aColors,
+                               aDpiRatio);
+}
+
+bool ScrollbarDrawingWin::PaintScrollbarThumb(
+    WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  return DoPaintScrollbarThumb(aWrData, aRect, aScrollbarKind, aFrame, aStyle,
+                               aElementState, aDocumentState, aColors,
+                               aDpiRatio);
+}
+
+void ScrollbarDrawingWin::RecomputeScrollbarParams() {
+  uint32_t defaultSize = kDefaultWinScrollbarSize;
+  uint32_t overrideSize =
+      StaticPrefs::widget_non_native_theme_scrollbar_size_override();
+  if (overrideSize > 0) {
+    defaultSize = overrideSize;
+  }
+  ConfigureScrollbarSize(defaultSize);
+
+  if (StaticPrefs::widget_non_native_theme_win_scrollbar_use_system_size()) {
+    ConfigureScrollbarSize(LookAndFeel::GetInt(
+        LookAndFeel::IntID::SystemScrollbarSize, defaultSize));
+  }
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/ScrollbarDrawingWin.h b/widget/ScrollbarDrawingWin.h
new file mode 100644
index 0000000000..adc79035c2
--- /dev/null
+++ b/widget/ScrollbarDrawingWin.h
@@ -0,0 +1,55 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_ScrollbarDrawingWin_h
+#define mozilla_widget_ScrollbarDrawingWin_h
+
+#include "nsITheme.h"
+#include "nsNativeTheme.h"
+#include "ScrollbarDrawing.h"
+
+namespace mozilla::widget {
+
+class ScrollbarDrawingWin : public ScrollbarDrawing {
+ protected:
+  explicit ScrollbarDrawingWin(Kind aKind) : ScrollbarDrawing(aKind) {}
+
+ public:
+  ScrollbarDrawingWin() : ScrollbarDrawingWin(Kind::Win10) {}
+
+  virtual ~ScrollbarDrawingWin() = default;
+
+  LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*,
+                                           StyleAppearance aAppearance,
+                                           nsIFrame* aFrame) override;
+
+  Maybe<nsITheme::Transparency> GetScrollbarPartTransparency(
+      nsIFrame* aFrame, StyleAppearance aAppearance) override;
+
+  template <typename PaintBackendData>
+  bool DoPaintScrollbarThumb(PaintBackendData&, const LayoutDeviceRect&,
+                             ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                             const ElementState& aElementState,
+                             const DocumentState& aDocumentState, const Colors&,
+                             const DPIRatio&);
+  bool PaintScrollbarThumb(DrawTarget&, const LayoutDeviceRect&, ScrollbarKind,
+                           nsIFrame*, const ComputedStyle&,
+                           const ElementState& aElementState,
+                           const DocumentState& aDocumentState, const Colors&,
+                           const DPIRatio&) override;
+  bool PaintScrollbarThumb(WebRenderBackendData&, const LayoutDeviceRect&,
+                           ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                           const ElementState& aElementState,
+                           const DocumentState& aDocumentState, const Colors&,
+                           const DPIRatio&) override;
+
+  void RecomputeScrollbarParams() override;
+};
+
+static constexpr uint32_t kDefaultWinScrollbarSize = 17;
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/ScrollbarDrawingWin11.cpp b/widget/ScrollbarDrawingWin11.cpp
new file mode 100644
index 0000000000..8517b60baa
--- /dev/null
+++ b/widget/ScrollbarDrawingWin11.cpp
@@ -0,0 +1,364 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScrollbarDrawingWin11.h"
+
+#include "mozilla/gfx/Helpers.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsLayoutUtils.h"
+#include "Theme.h"
+#include "nsNativeTheme.h"
+
+using mozilla::gfx::sRGBColor;
+
+namespace mozilla::widget {
+
+// There are effectively three kinds of scrollbars in Windows 11:
+//
+//  * Overlay scrollbars (the ones where the scrollbar disappears automatically
+//    and doesn't take space)
+//  * Non-overlay scrollbar with thin (overlay-like) thumb.
+//  * Non-overlay scrollbar with thick thumb.
+//
+// See bug 1755193 for some discussion on non-overlay scrollbar styles.
+enum class Style {
+  Overlay,
+  ThinThumb,
+  ThickThumb,
+};
+
+static Style ScrollbarStyle(nsPresContext* aPresContext) {
+  if (aPresContext->UseOverlayScrollbars()) {
+    return Style::Overlay;
+  }
+  if (StaticPrefs::
+          widget_non_native_theme_win11_scrollbar_force_overlay_style()) {
+    return Style::ThinThumb;
+  }
+  return Style::ThickThumb;
+}
+
+static constexpr CSSIntCoord kDefaultWinOverlayScrollbarSize = CSSIntCoord(12);
+static constexpr CSSIntCoord kDefaultWinOverlayThinScrollbarSize =
+    CSSIntCoord(10);
+
+LayoutDeviceIntSize ScrollbarDrawingWin11::GetMinimumWidgetSize(
+    nsPresContext* aPresContext, StyleAppearance aAppearance,
+    nsIFrame* aFrame) {
+  MOZ_ASSERT(nsNativeTheme::IsWidgetScrollbarPart(aAppearance));
+  if (ScrollbarStyle(aPresContext) != Style::ThinThumb) {
+    return ScrollbarDrawingWin::GetMinimumWidgetSize(aPresContext, aAppearance,
+                                                     aFrame);
+  }
+  constexpr float kArrowRatio = 14.0f / kDefaultWinScrollbarSize;
+  switch (aAppearance) {
+    case StyleAppearance::ScrollbarbuttonUp:
+    case StyleAppearance::ScrollbarbuttonDown:
+    case StyleAppearance::ScrollbarbuttonLeft:
+    case StyleAppearance::ScrollbarbuttonRight: {
+      if (IsScrollbarWidthThin(aFrame)) {
+        return {};
+      }
+      const LayoutDeviceIntCoord size =
+          ScrollbarDrawing::GetScrollbarSize(aPresContext, aFrame);
+      return LayoutDeviceIntSize{
+          size, (kArrowRatio * LayoutDeviceCoord(size)).Rounded()};
+    }
+    default:
+      return ScrollbarDrawingWin::GetMinimumWidgetSize(aPresContext,
+                                                       aAppearance, aFrame);
+  }
+}
+
+sRGBColor ScrollbarDrawingWin11::ComputeScrollbarTrackColor(
+    nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const DocumentState& aDocumentState, const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    return ScrollbarDrawingWin::ComputeScrollbarTrackColor(
+        aFrame, aStyle, aDocumentState, aColors);
+  }
+  const nsStyleUI* ui = aStyle.StyleUI();
+  if (ui->mScrollbarColor.IsColors()) {
+    return sRGBColor::FromABGR(
+        ui->mScrollbarColor.AsColors().track.CalcColor(aStyle));
+  }
+  return aColors.IsDark() ? sRGBColor::FromU8(23, 23, 23, 255)
+                          : sRGBColor::FromU8(240, 240, 240, 255);
+}
+
+sRGBColor ScrollbarDrawingWin11::ComputeScrollbarThumbColor(
+    nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    return ScrollbarDrawingWin::ComputeScrollbarThumbColor(
+        aFrame, aStyle, aElementState, aDocumentState, aColors);
+  }
+  const nscolor baseColor = [&] {
+    const nsStyleUI* ui = aStyle.StyleUI();
+    if (ui->mScrollbarColor.IsColors()) {
+      return ui->mScrollbarColor.AsColors().thumb.CalcColor(aStyle);
+    }
+    return aColors.IsDark() ? NS_RGBA(149, 149, 149, 255)
+                            : NS_RGBA(133, 133, 133, 255);
+  }();
+  ElementState state = aElementState;
+  if (!IsScrollbarWidthThin(aStyle)) {
+    // non-thin scrollbars get hover feedback by changing thumb shape, so we
+    // only provide active feedback (and we use the hover state for that as it's
+    // more subtle).
+    state &= ~ElementState::HOVER;
+    if (state.HasState(ElementState::ACTIVE)) {
+      state &= ~ElementState::ACTIVE;
+      state |= ElementState::HOVER;
+    }
+  }
+  return sRGBColor::FromABGR(
+      ThemeColors::AdjustUnthemedScrollbarThumbColor(baseColor, state));
+}
+
+std::pair<sRGBColor, sRGBColor>
+ScrollbarDrawingWin11::ComputeScrollbarButtonColors(
+    nsIFrame* aFrame, StyleAppearance aAppearance, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    return ScrollbarDrawingWin::ComputeScrollbarButtonColors(
+        aFrame, aAppearance, aStyle, aElementState, aDocumentState, aColors);
+  }
+  // The button always looks transparent (the track behind it is visible), so we
+  // can hardcode it.
+  sRGBColor arrowColor = ComputeScrollbarThumbColor(
+      aFrame, aStyle, aElementState, aDocumentState, aColors);
+  return {sRGBColor::White(0.0f), arrowColor};
+}
+
+bool ScrollbarDrawingWin11::PaintScrollbarButton(
+    DrawTarget& aDrawTarget, StyleAppearance aAppearance,
+    const LayoutDeviceRect& aRect, ScrollbarKind aScrollbarKind,
+    nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  if (!ScrollbarDrawing::IsParentScrollbarHoveredOrActive(aFrame)) {
+    return true;
+  }
+
+  const auto style = ScrollbarStyle(aFrame->PresContext());
+  auto [buttonColor, arrowColor] = ComputeScrollbarButtonColors(
+      aFrame, aAppearance, aStyle, aElementState, aDocumentState, aColors);
+  if (style != Style::Overlay) {
+    aDrawTarget.FillRect(aRect.ToUnknownRect(),
+                         gfx::ColorPattern(ToDeviceColor(buttonColor)));
+  }
+
+  // Start with Up arrow.
+  float arrowPolygonX[] = {-4.5f, 4.5f, 4.5f, 0.5f, -0.5f, -4.5f, -4.5f};
+  float arrowPolygonXActive[] = {-4.0f,  4.0f,  4.0f, -0.25f,
+                                 -0.25f, -4.0f, -4.0f};
+  float arrowPolygonXHover[] = {-5.0f, 5.0f, 5.0f, 0.75f, -0.75f, -5.0f, -5.0f};
+  float arrowPolygonY[] = {2.5f, 2.5f, 1.0f, -4.0f, -4.0f, 1.0f, 2.5f};
+  float arrowPolygonYActive[] = {2.0f, 2.0f, 0.5f, -3.5f, -3.5f, 0.5f, 2.0f};
+  float arrowPolygonYHover[] = {3.0f, 3.0f, 1.5f, -4.5f, -4.5f, 1.5f, 3.0f};
+  float* arrowX = arrowPolygonX;
+  float* arrowY = arrowPolygonY;
+  const bool horizontal = aScrollbarKind == ScrollbarKind::Horizontal;
+
+  const float verticalOffset = [&] {
+    if (style != Style::Overlay) {
+      return 0.0f;
+    }
+    // To compensate for the scrollbar track radius we shift stuff vertically a
+    // bit. This 1px is arbitrary, but enough for the triangle not to overflow.
+    return 1.0f;
+  }();
+  const float horizontalOffset = [&] {
+    if (style != Style::ThinThumb) {
+      return 0.0f;  // Always center it in the rect.
+    }
+    // Compensate for the displacement we do of the thumb position by displacing
+    // the arrow as well, see comment in DoPaintScrollbarThumb.
+    if (horizontal) {
+      return -0.5f;
+    }
+    return aScrollbarKind == ScrollbarKind::VerticalRight ? 0.5f : -0.5f;
+  }();
+  const float polygonSize = style == Style::Overlay
+                                ? float(kDefaultWinOverlayScrollbarSize)
+                                : float(kDefaultWinScrollbarSize);
+  const int32_t arrowNumPoints = ArrayLength(arrowPolygonX);
+
+  if (aElementState.HasState(ElementState::ACTIVE)) {
+    arrowX = arrowPolygonXActive;
+    arrowY = arrowPolygonYActive;
+  } else if (aElementState.HasState(ElementState::HOVER)) {
+    arrowX = arrowPolygonXHover;
+    arrowY = arrowPolygonYHover;
+  }
+
+  switch (aAppearance) {
+    case StyleAppearance::ScrollbarbuttonDown:
+    case StyleAppearance::ScrollbarbuttonRight:
+      for (int32_t i = 0; i < arrowNumPoints; i++) {
+        arrowY[i] += verticalOffset;
+        arrowY[i] *= -1;
+      }
+      [[fallthrough]];
+    case StyleAppearance::ScrollbarbuttonUp:
+    case StyleAppearance::ScrollbarbuttonLeft:
+      if (horizontalOffset != 0.0f) {
+        for (int32_t i = 0; i < arrowNumPoints; i++) {
+          arrowX[i] += horizontalOffset;
+        }
+      }
+      break;
+    default:
+      return false;
+  }
+
+  if (horizontal) {
+    std::swap(arrowX, arrowY);
+  }
+
+  LayoutDeviceRect arrowRect(aRect);
+  if (style != Style::ThinThumb) {
+    auto margin = CSSCoord(style == Style::Overlay ? 1 : 2) * aDpiRatio;
+    arrowRect.Deflate(margin, margin);
+  }
+
+  ThemeDrawing::PaintArrow(aDrawTarget, arrowRect, arrowX, arrowY, polygonSize,
+                           arrowNumPoints, arrowColor);
+  return true;
+}
+
+template <typename PaintBackendData>
+bool ScrollbarDrawingWin11::DoPaintScrollbarThumb(
+    PaintBackendData& aPaintData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  sRGBColor thumbColor = ComputeScrollbarThumbColor(
+      aFrame, aStyle, aElementState, aDocumentState, aColors);
+
+  LayoutDeviceRect thumbRect(aRect);
+
+  const auto style = ScrollbarStyle(aFrame->PresContext());
+  const bool hovered =
+      ScrollbarDrawing::IsParentScrollbarHoveredOrActive(aFrame) ||
+      (style != Style::Overlay && IsScrollbarWidthThin(aStyle));
+  const bool horizontal = aScrollbarKind == ScrollbarKind::Horizontal;
+  if (style == Style::ThickThumb) {
+    constexpr float kHoveredThumbRatio =
+        (1.0f - (11.0f / kDefaultWinScrollbarSize)) / 2.0f;
+    constexpr float kUnhoveredThumbRatio =
+        (1.0f - (9.0f / kDefaultWinScrollbarSize)) / 2.0f;
+    const float ratio = hovered ? kHoveredThumbRatio : kUnhoveredThumbRatio;
+    if (horizontal) {
+      thumbRect.Deflate(0, thumbRect.height * ratio);
+    } else {
+      thumbRect.Deflate(thumbRect.width * ratio, 0);
+    }
+
+    auto radius = CSSCoord(hovered ? 2 : 0);
+    ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, thumbRect, thumbColor,
+                                             sRGBColor(), 0, radius, aDpiRatio);
+    return true;
+  }
+
+  const float defaultTrackSize = style == Style::Overlay
+                                     ? float(kDefaultWinOverlayScrollbarSize)
+                                     : float(kDefaultWinScrollbarSize);
+  const float trackSize = horizontal ? thumbRect.height : thumbRect.width;
+  const float thumbSizeInPixels = hovered ? 6.0f : 2.0f;
+
+  // The thumb might be a bit off-center, depending on our scrollbar styles.
+  //
+  // Hovered shifts, if any, need to be accounted for in PaintScrollbarButton.
+  // For example, for the hovered horizontal thin scrollbar shift:
+  //
+  //   Scrollbar is 17px high by default. We make the thumb 6px tall and move
+  //   it 5px towards the bottom, so the center (8.5 initially) is displaced
+  //   by:
+  //     (5px + 6px / 2) - 8.5px = -0.5px
+  //
+  // Same calculations apply to other shifts.
+  const float shiftInPixels = [&] {
+    if (style == Style::Overlay) {
+      if (hovered) {
+        // Keep the center intact.
+        return (defaultTrackSize - thumbSizeInPixels) / 2.0f;
+      }
+      // We want logical pixels from the thumb to the edge. For LTR and
+      // horizontal scrollbars that means shifting down the scrollbar size minus
+      // the thumb.
+      constexpr float kSpaceToEdge = 3.0f;
+      if (horizontal || aScrollbarKind == ScrollbarKind::VerticalRight) {
+        return defaultTrackSize - thumbSizeInPixels - kSpaceToEdge;
+      }
+      // For rtl is simpler.
+      return kSpaceToEdge;
+    }
+    if (horizontal) {
+      return hovered ? 5.0f : 7.0f;
+    }
+    const bool ltr = aScrollbarKind == ScrollbarKind::VerticalRight;
+    return ltr ? (hovered ? 6.0f : 8.0f) : (hovered ? 5.0f : 7.0f);
+  }();
+
+  if (horizontal) {
+    thumbRect.y += shiftInPixels * trackSize / defaultTrackSize;
+    thumbRect.height *= thumbSizeInPixels / defaultTrackSize;
+  } else {
+    thumbRect.x += shiftInPixels * trackSize / defaultTrackSize;
+    thumbRect.width *= thumbSizeInPixels / defaultTrackSize;
+  }
+
+  if (style == Style::Overlay || hovered) {
+    LayoutDeviceCoord radius =
+        (horizontal ? thumbRect.height : thumbRect.width) / 2.0f;
+
+    MOZ_ASSERT(aRect.Contains(thumbRect));
+    ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, thumbRect, thumbColor,
+                                             sRGBColor(), 0, radius / aDpiRatio,
+                                             aDpiRatio);
+    return true;
+  }
+
+  ThemeDrawing::FillRect(aPaintData, thumbRect, thumbColor);
+  return true;
+}
+
+bool ScrollbarDrawingWin11::PaintScrollbarThumb(
+    DrawTarget& aDrawTarget, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  return DoPaintScrollbarThumb(aDrawTarget, aRect, aScrollbarKind, aFrame,
+                               aStyle, aElementState, aDocumentState, aColors,
+                               aDpiRatio);
+}
+
+bool ScrollbarDrawingWin11::PaintScrollbarThumb(
+    WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
+    ScrollbarKind aScrollbarKind, nsIFrame* aFrame, const ComputedStyle& aStyle,
+    const ElementState& aElementState, const DocumentState& aDocumentState,
+    const Colors& aColors, const DPIRatio& aDpiRatio) {
+  return DoPaintScrollbarThumb(aWrData, aRect, aScrollbarKind, aFrame, aStyle,
+                               aElementState, aDocumentState, aColors,
+                               aDpiRatio);
+}
+
+void ScrollbarDrawingWin11::RecomputeScrollbarParams() {
+  ScrollbarDrawingWin::RecomputeScrollbarParams();
+  // TODO(emilio): Maybe make this configurable? Though this doesn't respect
+  // classic Windows registry settings, and cocoa overlay scrollbars also don't
+  // respect the override it seems, so this should be fine.
+  ConfigureScrollbarSize(StyleScrollbarWidth::Thin, Overlay::Yes,
+                         kDefaultWinOverlayThinScrollbarSize);
+  ConfigureScrollbarSize(StyleScrollbarWidth::Auto, Overlay::Yes,
+                         kDefaultWinOverlayScrollbarSize);
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/ScrollbarDrawingWin11.h b/widget/ScrollbarDrawingWin11.h
new file mode 100644
index 0000000000..67d572d966
--- /dev/null
+++ b/widget/ScrollbarDrawingWin11.h
@@ -0,0 +1,68 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_ScrollbarDrawingWin11_h
+#define mozilla_widget_ScrollbarDrawingWin11_h
+
+#include "nsITheme.h"
+#include "nsNativeTheme.h"
+#include "ScrollbarDrawing.h"
+#include "ScrollbarDrawingWin.h"
+
+namespace mozilla::widget {
+
+class ScrollbarDrawingWin11 final : public ScrollbarDrawingWin {
+ public:
+  ScrollbarDrawingWin11() : ScrollbarDrawingWin(Kind::Win11) {}
+  virtual ~ScrollbarDrawingWin11() = default;
+
+  LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*,
+                                           StyleAppearance aAppearance,
+                                           nsIFrame* aFrame) override;
+
+  sRGBColor ComputeScrollbarTrackColor(nsIFrame*, const ComputedStyle&,
+                                       const DocumentState& aDocumentState,
+                                       const Colors&) override;
+  sRGBColor ComputeScrollbarThumbColor(nsIFrame*, const ComputedStyle&,
+                                       const ElementState& aElementState,
+                                       const DocumentState& aDocumentState,
+                                       const Colors&) override;
+
+  // Returned colors are button, arrow.
+  std::pair<sRGBColor, sRGBColor> ComputeScrollbarButtonColors(
+      nsIFrame*, StyleAppearance, const ComputedStyle&,
+      const ElementState& aElementState, const DocumentState& aDocumentState,
+      const Colors&) override;
+
+  bool PaintScrollbarButton(DrawTarget&, StyleAppearance,
+                            const LayoutDeviceRect&, ScrollbarKind, nsIFrame*,
+                            const ComputedStyle&,
+                            const ElementState& aElementState,
+                            const DocumentState& aDocumentState, const Colors&,
+                            const DPIRatio&) override;
+
+  template <typename PaintBackendData>
+  bool DoPaintScrollbarThumb(PaintBackendData&, const LayoutDeviceRect&,
+                             ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                             const ElementState& aElementState,
+                             const DocumentState& aDocumentState, const Colors&,
+                             const DPIRatio&);
+  bool PaintScrollbarThumb(DrawTarget&, const LayoutDeviceRect&, ScrollbarKind,
+                           nsIFrame*, const ComputedStyle&,
+                           const ElementState& aElementState,
+                           const DocumentState& aDocumentState, const Colors&,
+                           const DPIRatio&) override;
+  bool PaintScrollbarThumb(WebRenderBackendData&, const LayoutDeviceRect&,
+                           ScrollbarKind, nsIFrame*, const ComputedStyle&,
+                           const ElementState& aElementState,
+                           const DocumentState& aDocumentState, const Colors&,
+                           const DPIRatio&) override;
+
+  void RecomputeScrollbarParams() override;
+};
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/SharedWidgetUtils.cpp b/widget/SharedWidgetUtils.cpp
new file mode 100644
index 0000000000..f1c71b5c66
--- /dev/null
+++ b/widget/SharedWidgetUtils.cpp
@@ -0,0 +1,273 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WidgetUtils.h"
+
+#include "mozilla/TextEvents.h"
+
+#include "nsIBaseWindow.h"
+#include "nsIDocShellTreeItem.h"
+#include "nsIDocShell.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsPIDOMWindow.h"
+
+namespace mozilla {
+namespace widget {
+
+// static
+void WidgetUtils::Shutdown() {
+  WidgetKeyboardEvent::Shutdown();
+  InternalEditorInputEvent::Shutdown();
+}
+
+// static
+already_AddRefed<nsIWidget> WidgetUtils::DOMWindowToWidget(
+    nsPIDOMWindowOuter* aDOMWindow) {
+  nsCOMPtr<nsIWidget> widget;
+  nsCOMPtr<nsPIDOMWindowOuter> window = aDOMWindow;
+
+  if (window) {
+    nsCOMPtr<nsIBaseWindow> baseWin(do_QueryInterface(window->GetDocShell()));
+
+    while (!widget && baseWin) {
+      baseWin->GetParentWidget(getter_AddRefs(widget));
+      if (!widget) {
+        nsCOMPtr<nsIDocShellTreeItem> docShellAsItem(
+            do_QueryInterface(baseWin));
+        if (!docShellAsItem) return nullptr;
+
+        nsCOMPtr<nsIDocShellTreeItem> parent;
+        docShellAsItem->GetInProcessParent(getter_AddRefs(parent));
+
+        window = do_GetInterface(parent);
+        if (!window) return nullptr;
+
+        baseWin = do_QueryInterface(window->GetDocShell());
+      }
+    }
+  }
+
+  return widget.forget();
+}
+
+// static
+uint32_t WidgetUtils::ComputeKeyCodeFromChar(uint32_t aCharCode) {
+  if (aCharCode >= 'A' && aCharCode <= 'Z') {
+    return aCharCode - 'A' + NS_VK_A;
+  }
+  if (aCharCode >= 'a' && aCharCode <= 'z') {
+    return aCharCode - 'a' + NS_VK_A;
+  }
+  if (aCharCode >= '0' && aCharCode <= '9') {
+    return aCharCode - '0' + NS_VK_0;
+  }
+  switch (aCharCode) {
+    case ' ':
+      return NS_VK_SPACE;
+    case '\t':
+      return NS_VK_TAB;
+    case ':':
+      return NS_VK_COLON;
+    case ';':
+      return NS_VK_SEMICOLON;
+    case '<':
+      return NS_VK_LESS_THAN;
+    case '=':
+      return NS_VK_EQUALS;
+    case '>':
+      return NS_VK_GREATER_THAN;
+    case '?':
+      return NS_VK_QUESTION_MARK;
+    case '@':
+      return NS_VK_AT;
+    case '^':
+      return NS_VK_CIRCUMFLEX;
+    case '!':
+      return NS_VK_EXCLAMATION;
+    case '"':
+      return NS_VK_DOUBLE_QUOTE;
+    case '#':
+      return NS_VK_HASH;
+    case '$':
+      return NS_VK_DOLLAR;
+    case '%':
+      return NS_VK_PERCENT;
+    case '&':
+      return NS_VK_AMPERSAND;
+    case '_':
+      return NS_VK_UNDERSCORE;
+    case '(':
+      return NS_VK_OPEN_PAREN;
+    case ')':
+      return NS_VK_CLOSE_PAREN;
+    case '*':
+      return NS_VK_ASTERISK;
+    case '+':
+      return NS_VK_PLUS;
+    case '|':
+      return NS_VK_PIPE;
+    case '-':
+      return NS_VK_HYPHEN_MINUS;
+    case '{':
+      return NS_VK_OPEN_CURLY_BRACKET;
+    case '}':
+      return NS_VK_CLOSE_CURLY_BRACKET;
+    case '~':
+      return NS_VK_TILDE;
+    case ',':
+      return NS_VK_COMMA;
+    case '.':
+      return NS_VK_PERIOD;
+    case '/':
+      return NS_VK_SLASH;
+    case '`':
+      return NS_VK_BACK_QUOTE;
+    case '[':
+      return NS_VK_OPEN_BRACKET;
+    case '\\':
+      return NS_VK_BACK_SLASH;
+    case ']':
+      return NS_VK_CLOSE_BRACKET;
+    case '\'':
+      return NS_VK_QUOTE;
+  }
+  return 0;
+}
+
+// static
+void WidgetUtils::GetLatinCharCodeForKeyCode(uint32_t aKeyCode,
+                                             bool aIsCapsLock,
+                                             uint32_t* aUnshiftedCharCode,
+                                             uint32_t* aShiftedCharCode) {
+  MOZ_ASSERT(aUnshiftedCharCode && aShiftedCharCode,
+             "aUnshiftedCharCode and aShiftedCharCode must not be NULL");
+
+  if (aKeyCode >= NS_VK_A && aKeyCode <= NS_VK_Z) {
+    *aUnshiftedCharCode = *aShiftedCharCode = aKeyCode;
+    if (aIsCapsLock) {
+      *aShiftedCharCode += 0x20;
+    } else {
+      *aUnshiftedCharCode += 0x20;
+    }
+    return;
+  }
+
+  // aShiftedCharCode must be zero for non-alphabet keys.
+  *aShiftedCharCode = 0;
+
+  if (aKeyCode >= NS_VK_0 && aKeyCode <= NS_VK_9) {
+    *aUnshiftedCharCode = aKeyCode;
+    return;
+  }
+
+  switch (aKeyCode) {
+    case NS_VK_SPACE:
+      *aUnshiftedCharCode = ' ';
+      break;
+    case NS_VK_COLON:
+      *aUnshiftedCharCode = ':';
+      break;
+    case NS_VK_SEMICOLON:
+      *aUnshiftedCharCode = ';';
+      break;
+    case NS_VK_LESS_THAN:
+      *aUnshiftedCharCode = '<';
+      break;
+    case NS_VK_EQUALS:
+      *aUnshiftedCharCode = '=';
+      break;
+    case NS_VK_GREATER_THAN:
+      *aUnshiftedCharCode = '>';
+      break;
+    case NS_VK_QUESTION_MARK:
+      *aUnshiftedCharCode = '?';
+      break;
+    case NS_VK_AT:
+      *aUnshiftedCharCode = '@';
+      break;
+    case NS_VK_CIRCUMFLEX:
+      *aUnshiftedCharCode = '^';
+      break;
+    case NS_VK_EXCLAMATION:
+      *aUnshiftedCharCode = '!';
+      break;
+    case NS_VK_DOUBLE_QUOTE:
+      *aUnshiftedCharCode = '"';
+      break;
+    case NS_VK_HASH:
+      *aUnshiftedCharCode = '#';
+      break;
+    case NS_VK_DOLLAR:
+      *aUnshiftedCharCode = '$';
+      break;
+    case NS_VK_PERCENT:
+      *aUnshiftedCharCode = '%';
+      break;
+    case NS_VK_AMPERSAND:
+      *aUnshiftedCharCode = '&';
+      break;
+    case NS_VK_UNDERSCORE:
+      *aUnshiftedCharCode = '_';
+      break;
+    case NS_VK_OPEN_PAREN:
+      *aUnshiftedCharCode = '(';
+      break;
+    case NS_VK_CLOSE_PAREN:
+      *aUnshiftedCharCode = ')';
+      break;
+    case NS_VK_ASTERISK:
+      *aUnshiftedCharCode = '*';
+      break;
+    case NS_VK_PLUS:
+      *aUnshiftedCharCode = '+';
+      break;
+    case NS_VK_PIPE:
+      *aUnshiftedCharCode = '|';
+      break;
+    case NS_VK_HYPHEN_MINUS:
+      *aUnshiftedCharCode = '-';
+      break;
+    case NS_VK_OPEN_CURLY_BRACKET:
+      *aUnshiftedCharCode = '{';
+      break;
+    case NS_VK_CLOSE_CURLY_BRACKET:
+      *aUnshiftedCharCode = '}';
+      break;
+    case NS_VK_TILDE:
+      *aUnshiftedCharCode = '~';
+      break;
+    case NS_VK_COMMA:
+      *aUnshiftedCharCode = ',';
+      break;
+    case NS_VK_PERIOD:
+      *aUnshiftedCharCode = '.';
+      break;
+    case NS_VK_SLASH:
+      *aUnshiftedCharCode = '/';
+      break;
+    case NS_VK_BACK_QUOTE:
+      *aUnshiftedCharCode = '`';
+      break;
+    case NS_VK_OPEN_BRACKET:
+      *aUnshiftedCharCode = '[';
+      break;
+    case NS_VK_BACK_SLASH:
+      *aUnshiftedCharCode = '\\';
+      break;
+    case NS_VK_CLOSE_BRACKET:
+      *aUnshiftedCharCode = ']';
+      break;
+    case NS_VK_QUOTE:
+      *aUnshiftedCharCode = '\'';
+      break;
+    default:
+      *aUnshiftedCharCode = 0;
+      break;
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/SwipeTracker.cpp b/widget/SwipeTracker.cpp
new file mode 100644
index 0000000000..7474432e71
--- /dev/null
+++ b/widget/SwipeTracker.cpp
@@ -0,0 +1,272 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "SwipeTracker.h"
+
+#include "InputData.h"
+#include "mozilla/FlushType.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/TouchEvents.h"
+#include "mozilla/dom/SimpleGestureEventBinding.h"
+#include "nsAlgorithm.h"
+#include "nsIWidget.h"
+#include "nsRefreshDriver.h"
+#include "UnitTransforms.h"
+
+// These values were tweaked to make the physics feel similar to the native
+// swipe.
+static const double kSpringForce = 250.0;
+static const double kSwipeSuccessThreshold = 0.25;
+
+namespace mozilla {
+
+static already_AddRefed<nsRefreshDriver> GetRefreshDriver(nsIWidget& aWidget) {
+  nsIWidgetListener* widgetListener = aWidget.GetWidgetListener();
+  PresShell* presShell =
+      widgetListener ? widgetListener->GetPresShell() : nullptr;
+  nsPresContext* presContext =
+      presShell ? presShell->GetPresContext() : nullptr;
+  RefPtr<nsRefreshDriver> refreshDriver =
+      presContext ? presContext->RefreshDriver() : nullptr;
+  return refreshDriver.forget();
+}
+
+SwipeTracker::SwipeTracker(nsIWidget& aWidget,
+                           const PanGestureInput& aSwipeStartEvent,
+                           uint32_t aAllowedDirections,
+                           uint32_t aSwipeDirection)
+    : mWidget(aWidget),
+      mRefreshDriver(GetRefreshDriver(mWidget)),
+      mAxis(0.0, 0.0, 0.0, kSpringForce, 1.0),
+      mEventPosition(RoundedToInt(ViewAs<LayoutDevicePixel>(
+          aSwipeStartEvent.mPanStartPoint,
+          PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent))),
+      mLastEventTimeStamp(aSwipeStartEvent.mTimeStamp),
+      mAllowedDirections(aAllowedDirections),
+      mSwipeDirection(aSwipeDirection) {
+  SendSwipeEvent(eSwipeGestureStart, 0, 0.0, aSwipeStartEvent.mTimeStamp);
+  ProcessEvent(aSwipeStartEvent, /* aProcessingFirstEvent = */ true);
+}
+
+void SwipeTracker::Destroy() { UnregisterFromRefreshDriver(); }
+
+SwipeTracker::~SwipeTracker() {
+  MOZ_RELEASE_ASSERT(!mRegisteredWithRefreshDriver,
+                     "Destroy needs to be called before deallocating");
+}
+
+double SwipeTracker::SwipeSuccessTargetValue() const {
+  return mSwipeDirection == dom::SimpleGestureEvent_Binding::DIRECTION_RIGHT
+             ? -1.0
+             : 1.0;
+}
+
+double SwipeTracker::ClampToAllowedRange(double aGestureAmount) const {
+  // gestureAmount needs to stay between -1 and 0 when swiping right and
+  // between 0 and 1 when swiping left.
+  double min =
+      mSwipeDirection == dom::SimpleGestureEvent_Binding::DIRECTION_RIGHT ? -1.0
+                                                                          : 0.0;
+  double max =
+      mSwipeDirection == dom::SimpleGestureEvent_Binding::DIRECTION_LEFT ? 1.0
+                                                                         : 0.0;
+  return clamped(aGestureAmount, min, max);
+}
+
+bool SwipeTracker::ComputeSwipeSuccess() const {
+  double targetValue = SwipeSuccessTargetValue();
+
+  // If the fingers were moving away from the target direction when they were
+  // lifted from the touchpad, abort the swipe.
+  if (mCurrentVelocity * targetValue <
+      -StaticPrefs::widget_swipe_velocity_twitch_tolerance()) {
+    return false;
+  }
+
+  return (mGestureAmount * targetValue +
+          mCurrentVelocity * targetValue *
+              StaticPrefs::widget_swipe_success_velocity_contribution()) >=
+         kSwipeSuccessThreshold;
+}
+
+nsEventStatus SwipeTracker::ProcessEvent(
+    const PanGestureInput& aEvent, bool aProcessingFirstEvent /* = false */) {
+  // If the fingers have already been lifted or the swipe direction is where
+  // navigation is impossible, don't process this event for swiping.
+  if (!mEventsAreControllingSwipe || !SwipingInAllowedDirection()) {
+    // Return nsEventStatus_eConsumeNoDefault for events from the swipe gesture
+    // and nsEventStatus_eIgnore for events of subsequent scroll gestures.
+    if (aEvent.mType == PanGestureInput::PANGESTURE_MAYSTART ||
+        aEvent.mType == PanGestureInput::PANGESTURE_START) {
+      mEventsHaveStartedNewGesture = true;
+    }
+    return mEventsHaveStartedNewGesture ? nsEventStatus_eIgnore
+                                        : nsEventStatus_eConsumeNoDefault;
+  }
+
+  mDeltaTypeIsPage = aEvent.mDeltaType == PanGestureInput::PANDELTA_PAGE;
+  double delta = [&]() -> double {
+    if (mDeltaTypeIsPage) {
+      return -aEvent.mPanDisplacement.x / StaticPrefs::widget_swipe_page_size();
+    }
+    return -aEvent.mPanDisplacement.x / mWidget.GetDefaultScaleInternal() /
+           StaticPrefs::widget_swipe_pixel_size();
+  }();
+
+  mGestureAmount = ClampToAllowedRange(mGestureAmount + delta);
+  if (aEvent.mType != PanGestureInput::PANGESTURE_END) {
+    if (!aProcessingFirstEvent) {
+      double elapsedSeconds = std::max(
+          0.008, (aEvent.mTimeStamp - mLastEventTimeStamp).ToSeconds());
+      mCurrentVelocity = delta / elapsedSeconds;
+    }
+    mLastEventTimeStamp = aEvent.mTimeStamp;
+  }
+
+  const bool computedSwipeSuccess = ComputeSwipeSuccess();
+  double eventAmount = mGestureAmount;
+  // If ComputeSwipeSuccess returned false because the users fingers were
+  // moving slightly away from the target direction then we do not want to
+  // display the UI as if we were at the success threshold as that would
+  // give a false indication that navigation would happen.
+  if (!computedSwipeSuccess && (eventAmount >= kSwipeSuccessThreshold ||
+                                eventAmount <= -kSwipeSuccessThreshold)) {
+    eventAmount = 0.999 * kSwipeSuccessThreshold;
+    if (mGestureAmount < 0.f) {
+      eventAmount = -eventAmount;
+    }
+  }
+
+  SendSwipeEvent(eSwipeGestureUpdate, 0, eventAmount, aEvent.mTimeStamp);
+
+  if (aEvent.mType == PanGestureInput::PANGESTURE_END) {
+    mEventsAreControllingSwipe = false;
+    if (computedSwipeSuccess) {
+      // Let's use same timestamp as previous event because this is caused by
+      // the preceding event.
+      SendSwipeEvent(eSwipeGesture, mSwipeDirection, 0.0, aEvent.mTimeStamp);
+      UnregisterFromRefreshDriver();
+      NS_DispatchToMainThread(
+          NS_NewRunnableFunction("SwipeTracker::SwipeFinished",
+                                 [swipeTracker = RefPtr<SwipeTracker>(this),
+                                  timeStamp = aEvent.mTimeStamp] {
+                                   swipeTracker->SwipeFinished(timeStamp);
+                                 }));
+    } else {
+      StartAnimating(eventAmount, 0.0);
+    }
+  }
+
+  return nsEventStatus_eConsumeNoDefault;
+}
+
+void SwipeTracker::StartAnimating(double aStartValue, double aTargetValue) {
+  mAxis.SetPosition(aStartValue);
+  mAxis.SetDestination(aTargetValue);
+  mAxis.SetVelocity(mCurrentVelocity);
+
+  mLastAnimationFrameTime = TimeStamp::Now();
+
+  // Add ourselves as a refresh driver observer. The refresh driver
+  // will call WillRefresh for each animation frame until we
+  // unregister ourselves.
+  MOZ_RELEASE_ASSERT(!mRegisteredWithRefreshDriver,
+                     "We only want a single refresh driver registration");
+  if (mRefreshDriver) {
+    mRefreshDriver->AddRefreshObserver(this, FlushType::Style,
+                                       "Swipe animation");
+    mRegisteredWithRefreshDriver = true;
+  }
+}
+
+void SwipeTracker::WillRefresh(TimeStamp aTime) {
+  // FIXME(emilio): shouldn't we be using `aTime`?
+  TimeStamp now = TimeStamp::Now();
+  mAxis.Simulate(now - mLastAnimationFrameTime);
+  mLastAnimationFrameTime = now;
+
+  const double wholeSize = mDeltaTypeIsPage
+                               ? StaticPrefs::widget_swipe_page_size()
+                               : StaticPrefs::widget_swipe_pixel_size();
+  // NOTE(emilio): It's unclear this makes sense for page-based swiping, but
+  // this preserves behavior and all platforms probably will end up converging
+  // in pixel-based pan input, so...
+  const double minIncrement = 1.0 / wholeSize;
+  const bool isFinished = mAxis.IsFinished(minIncrement);
+
+  mGestureAmount = isFinished ? mAxis.GetDestination() : mAxis.GetPosition();
+  SendSwipeEvent(eSwipeGestureUpdate, 0, mGestureAmount, now);
+
+  if (isFinished) {
+    UnregisterFromRefreshDriver();
+    SwipeFinished(now);
+  }
+}
+
+void SwipeTracker::CancelSwipe(const TimeStamp& aTimeStamp) {
+  SendSwipeEvent(eSwipeGestureEnd, 0, 0.0, aTimeStamp);
+}
+
+void SwipeTracker::SwipeFinished(const TimeStamp& aTimeStamp) {
+  SendSwipeEvent(eSwipeGestureEnd, 0, 0.0, aTimeStamp);
+  mWidget.SwipeFinished();
+}
+
+void SwipeTracker::UnregisterFromRefreshDriver() {
+  if (mRegisteredWithRefreshDriver) {
+    MOZ_ASSERT(mRefreshDriver, "How were we able to register, then?");
+    mRefreshDriver->RemoveRefreshObserver(this, FlushType::Style);
+    mRegisteredWithRefreshDriver = false;
+  }
+}
+
+/* static */ WidgetSimpleGestureEvent SwipeTracker::CreateSwipeGestureEvent(
+    EventMessage aMsg, nsIWidget* aWidget,
+    const LayoutDeviceIntPoint& aPosition, const TimeStamp& aTimeStamp) {
+  // XXX Why isn't this initialized with nsCocoaUtils::InitInputEvent()?
+  WidgetSimpleGestureEvent geckoEvent(true, aMsg, aWidget);
+  geckoEvent.mModifiers = 0;
+  // XXX How about geckoEvent.mTime?
+  geckoEvent.mTimeStamp = aTimeStamp;
+  geckoEvent.mRefPoint = aPosition;
+  geckoEvent.mButtons = 0;
+  return geckoEvent;
+}
+
+bool SwipeTracker::SendSwipeEvent(EventMessage aMsg, uint32_t aDirection,
+                                  double aDelta, const TimeStamp& aTimeStamp) {
+  WidgetSimpleGestureEvent geckoEvent =
+      CreateSwipeGestureEvent(aMsg, &mWidget, mEventPosition, aTimeStamp);
+  geckoEvent.mDirection = aDirection;
+  geckoEvent.mDelta = aDelta;
+  geckoEvent.mAllowedDirections = mAllowedDirections;
+  return mWidget.DispatchWindowEvent(geckoEvent);
+}
+
+// static
+bool SwipeTracker::CanTriggerSwipe(const PanGestureInput& aPanInput) {
+  if (StaticPrefs::widget_disable_swipe_tracker()) {
+    return false;
+  }
+
+  if (aPanInput.mType != PanGestureInput::PANGESTURE_START) {
+    return false;
+  }
+
+  // Only initiate horizontal tracking for events whose horizontal element is
+  // at least eight times larger than its vertical element. This minimizes
+  // performance problems with vertical scrolls (by minimizing the possibility
+  // that they'll be misinterpreted as horizontal swipes), while still
+  // tolerating a small vertical element to a true horizontal swipe.  The number
+  // '8' was arrived at by trial and error.
+  return std::abs(aPanInput.mPanDisplacement.x) >
+         std::abs(aPanInput.mPanDisplacement.y) * 8;
+}
+
+}  // namespace mozilla
diff --git a/widget/SwipeTracker.h b/widget/SwipeTracker.h
new file mode 100644
index 0000000000..e475cb3b29
--- /dev/null
+++ b/widget/SwipeTracker.h
@@ -0,0 +1,112 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef SwipeTracker_h
+#define SwipeTracker_h
+
+#include "EventForwards.h"
+#include "mozilla/layers/AxisPhysicsMSDModel.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/TimeStamp.h"
+#include "nsRefreshObservers.h"
+#include "Units.h"
+
+class nsIWidget;
+class nsRefreshDriver;
+
+namespace mozilla {
+
+class PanGestureInput;
+
+/**
+ * SwipeTracker turns PanGestureInput events into swipe events
+ * (WidgetSimpleGestureEvent) and dispatches them into Gecko.
+ * The swiping behavior mirrors the behavior of the Cocoa API
+ * -[NSEvent
+ *     trackSwipeEventWithOptions:dampenAmountThresholdMin:max:usingHandler:].
+ * The advantage of using this class over the Cocoa API is that this class
+ * properly supports submitting queued up events to it, and that it hopefully
+ * doesn't intermittently break scrolling the way the Cocoa API does (bug
+ * 927702).
+ *
+ * The swipe direction is either left or right. It is determined before the
+ * SwipeTracker is created and stays fixed during the swipe.
+ * During the swipe, the swipe has a current "value" which is between 0 and the
+ * target value. The target value is either 1 (swiping left) or -1 (swiping
+ * right) - see SwipeSuccessTargetValue().
+ * A swipe can either succeed or fail. If it succeeds, the swipe animation
+ * animates towards the success target value; if it fails, it animates back to
+ * a value of 0. A swipe can only succeed if the user is swiping in an allowed
+ * direction. (Since both the allowed directions and the swipe direction are
+ * known at swipe start time, it's clear from the beginning whether a swipe is
+ * doomed to fail. In that case, the purpose of the SwipeTracker is to simulate
+ * a bounce-back animation.)
+ */
+class SwipeTracker final : public nsARefreshObserver {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(SwipeTracker, override)
+
+  SwipeTracker(nsIWidget& aWidget, const PanGestureInput& aSwipeStartEvent,
+               uint32_t aAllowedDirections, uint32_t aSwipeDirection);
+
+  void Destroy();
+
+  nsEventStatus ProcessEvent(const PanGestureInput& aEvent,
+                             bool aProcessingFirstEvent = false);
+  void CancelSwipe(const TimeStamp& aTimeStamp);
+
+  static WidgetSimpleGestureEvent CreateSwipeGestureEvent(
+      EventMessage aMsg, nsIWidget* aWidget,
+      const LayoutDeviceIntPoint& aPosition, const TimeStamp& aTimeStamp);
+
+  // nsARefreshObserver
+  void WillRefresh(mozilla::TimeStamp aTime) override;
+
+  static bool CanTriggerSwipe(const PanGestureInput& aPanInput);
+
+ protected:
+  ~SwipeTracker();
+
+  bool SwipingInAllowedDirection() const {
+    return mAllowedDirections & mSwipeDirection;
+  }
+  double SwipeSuccessTargetValue() const;
+  double ClampToAllowedRange(double aGestureAmount) const;
+  bool ComputeSwipeSuccess() const;
+  void StartAnimating(double aStartValue, double aTargetValue);
+  void SwipeFinished(const TimeStamp& aTimeStamp);
+  void UnregisterFromRefreshDriver();
+  bool SendSwipeEvent(EventMessage aMsg, uint32_t aDirection, double aDelta,
+                      const TimeStamp& aTimeStamp);
+
+  nsIWidget& mWidget;
+  RefPtr<nsRefreshDriver> mRefreshDriver;
+  layers::AxisPhysicsMSDModel mAxis;
+  const LayoutDeviceIntPoint mEventPosition;
+  TimeStamp mLastEventTimeStamp;
+  TimeStamp mLastAnimationFrameTime;
+  const uint32_t mAllowedDirections;
+  const uint32_t mSwipeDirection;
+  double mGestureAmount = 0.0;
+  double mCurrentVelocity = 0.0;
+  bool mDeltaTypeIsPage = false;
+  bool mEventsAreControllingSwipe = true;
+  bool mEventsHaveStartedNewGesture = false;
+  bool mRegisteredWithRefreshDriver = false;
+};
+
+struct SwipeEventQueue {
+  SwipeEventQueue(uint32_t aAllowedDirections, uint64_t aInputBlockId)
+      : allowedDirections(aAllowedDirections), inputBlockId(aInputBlockId) {}
+
+  nsTArray<PanGestureInput> queuedEvents;
+  uint32_t allowedDirections;
+  uint64_t inputBlockId;
+};
+
+}  // namespace mozilla
+
+#endif  // SwipeTracker_h
diff --git a/widget/SystemTimeConverter.h b/widget/SystemTimeConverter.h
new file mode 100644
index 0000000000..aa2a760487
--- /dev/null
+++ b/widget/SystemTimeConverter.h
@@ -0,0 +1,233 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef SystemTimeConverter_h
+#define SystemTimeConverter_h
+
+#include <limits>
+#include <type_traits>
+#include "mozilla/TimeStamp.h"
+
+namespace mozilla {
+
+// Utility class that converts time values represented as an unsigned integral
+// number of milliseconds from one time source (e.g. a native event time) to
+// corresponding mozilla::TimeStamp objects.
+//
+// This class handles wrapping of integer values and skew between the time
+// source and mozilla::TimeStamp values.
+//
+// It does this by using an historical reference time recorded in both time
+// scales (i.e. both as a numerical time value and as a TimeStamp).
+//
+// For performance reasons, this class is careful to minimize calls to the
+// native "current time" function (e.g. gdk_x11_server_get_time) since this can
+// be slow.
+template <typename Time, typename TimeStampNowProvider = TimeStamp>
+class SystemTimeConverter {
+ public:
+  SystemTimeConverter()
+      : mReferenceTime(Time(0)),
+        mLastBackwardsSkewCheck(Time(0)),
+        kTimeRange(std::numeric_limits<Time>::max()),
+        kTimeHalfRange(kTimeRange / 2),
+        kBackwardsSkewCheckInterval(Time(2000)) {
+    static_assert(!std::is_signed_v<Time>, "Expected Time to be unsigned");
+  }
+
+  template <typename CurrentTimeGetter>
+  mozilla::TimeStamp GetTimeStampFromSystemTime(
+      Time aTime, CurrentTimeGetter& aCurrentTimeGetter) {
+    TimeStamp roughlyNow = TimeStampNowProvider::Now();
+
+    // If the reference time is not set, use the current time value to fill
+    // it in.
+    if (mReferenceTimeStamp.IsNull()) {
+      // This sometimes happens when ::GetMessageTime returns 0 for the first
+      // message on Windows.
+      if (!aTime) return roughlyNow;
+      UpdateReferenceTime(aTime, aCurrentTimeGetter);
+    }
+
+    // Check for skew between the source of Time values and TimeStamp values.
+    // We do this by comparing two durations (both in ms):
+    //
+    // i.  The duration from the reference time to the passed-in time.
+    //     (timeDelta in the diagram below)
+    // ii. The duration from the reference timestamp to the current time
+    //     based on TimeStamp::Now.
+    //     (timeStampDelta in the diagram below)
+    //
+    // Normally, we'd expect (ii) to be slightly larger than (i) to account
+    // for the time taken between generating the event and processing it.
+    //
+    // If (ii) - (i) is negative then the source of Time values is getting
+    // "ahead" of TimeStamp. We call this "forwards" skew below.
+    //
+    // For the reverse case, if (ii) - (i) is positive (and greater than some
+    // tolerance factor), then we may have "backwards" skew. This is often
+    // the case when we have a backlog of events and by the time we process
+    // them, the time given by the system is comparatively "old".
+    //
+    // The IsNewerThanTimestamp function computes the equivalent of |aTime| in
+    // the TimeStamp scale and returns that in |timeAsTimeStamp|.
+    //
+    // Graphically:
+    //
+    //                    mReferenceTime              aTime
+    // Time scale:      ........+.......................*........
+    //                          |--------timeDelta------|
+    //
+    //                  mReferenceTimeStamp             roughlyNow
+    // TimeStamp scale: ........+...........................*....
+    //                          |------timeStampDelta-------|
+    //
+    //                                                  |---|
+    //                                         roughlyNow-timeAsTimeStamp
+    //
+    TimeStamp timeAsTimeStamp;
+    bool newer = IsTimeNewerThanTimestamp(aTime, roughlyNow, &timeAsTimeStamp);
+
+    // Tolerance when detecting clock skew.
+    static const TimeDuration kTolerance = TimeDuration::FromMilliseconds(30.0);
+
+    // Check for forwards skew
+    if (newer) {
+      // Make aTime correspond to roughlyNow
+      UpdateReferenceTime(aTime, roughlyNow);
+
+      // We didn't have backwards skew so don't bother checking for
+      // backwards skew again for a little while.
+      mLastBackwardsSkewCheck = aTime;
+
+      return roughlyNow;
+    }
+
+    if (roughlyNow - timeAsTimeStamp <= kTolerance) {
+      // If the time between event times and TimeStamp values is within
+      // the tolerance then assume we don't have clock skew so we can
+      // avoid checking for backwards skew for a while.
+      mLastBackwardsSkewCheck = aTime;
+    } else if (aTime - mLastBackwardsSkewCheck > kBackwardsSkewCheckInterval) {
+      aCurrentTimeGetter.GetTimeAsyncForPossibleBackwardsSkew(roughlyNow);
+      mLastBackwardsSkewCheck = aTime;
+    }
+
+    // Finally, calculate the timestamp
+    return timeAsTimeStamp;
+  }
+
+  void CompensateForBackwardsSkew(Time aReferenceTime,
+                                  const TimeStamp& aLowerBound) {
+    // Check if we actually have backwards skew. Backwards skew looks like
+    // the following:
+    //
+    //        mReferenceTime
+    // Time:      ..+...a...b...c..........................
+    //
+    //     mReferenceTimeStamp
+    // TimeStamp: ..+.....a.....b.....c....................
+    //
+    // Converted
+    // time:      ......a'..b'..c'.........................
+    //
+    // What we need to do is bring mReferenceTime "forwards".
+    //
+    // Suppose when we get (c), we detect possible backwards skew and trigger
+    // an async request for the current time (which is passed in here as
+    // aReferenceTime).
+    //
+    // We end up with something like the following:
+    //
+    //        mReferenceTime     aReferenceTime
+    // Time:      ..+...a...b...c...v......................
+    //
+    //     mReferenceTimeStamp
+    // TimeStamp: ..+.....a.....b.....c..........x.........
+    //                                ^          ^
+    //                          aLowerBound  TimeStamp::Now()
+    //
+    // If the duration (aLowerBound - mReferenceTimeStamp) is greater than
+    // (aReferenceTime - mReferenceTime) then we know we have backwards skew.
+    //
+    // If that's not the case, then we probably just got caught behind
+    // temporarily.
+    if (IsTimeNewerThanTimestamp(aReferenceTime, aLowerBound, nullptr)) {
+      return;
+    }
+
+    // We have backwards skew; the equivalent TimeStamp for aReferenceTime lies
+    // somewhere between aLowerBound (which was the TimeStamp when we triggered
+    // the async request for the current time) and TimeStamp::Now().
+    //
+    // If aReferenceTime was waiting in the event queue for a long time, the
+    // equivalent TimeStamp might be much closer to aLowerBound than
+    // TimeStamp::Now() so for now we just set it to aLowerBound. That's
+    // guaranteed to be at least somewhat of an improvement.
+    UpdateReferenceTime(aReferenceTime, aLowerBound);
+  }
+
+ private:
+  template <typename CurrentTimeGetter>
+  void UpdateReferenceTime(Time aReferenceTime,
+                           const CurrentTimeGetter& aCurrentTimeGetter) {
+    Time currentTime = aCurrentTimeGetter.GetCurrentTime();
+    TimeStamp currentTimeStamp = TimeStampNowProvider::Now();
+    Time timeSinceReference = currentTime - aReferenceTime;
+    TimeStamp referenceTimeStamp =
+        currentTimeStamp - TimeDuration::FromMilliseconds(timeSinceReference);
+    UpdateReferenceTime(aReferenceTime, referenceTimeStamp);
+  }
+
+  void UpdateReferenceTime(Time aReferenceTime,
+                           const TimeStamp& aReferenceTimeStamp) {
+    mReferenceTime = aReferenceTime;
+    mReferenceTimeStamp = aReferenceTimeStamp;
+  }
+
+  bool IsTimeNewerThanTimestamp(Time aTime, TimeStamp aTimeStamp,
+                                TimeStamp* aTimeAsTimeStamp) {
+    Time timeDelta = aTime - mReferenceTime;
+
+    // Cast the result to signed 64-bit integer first since that should be
+    // enough to hold the range of values returned by ToMilliseconds() and
+    // the result of converting from double to an integer-type when the value
+    // is outside the integer range is undefined.
+    // Then we do an implicit cast to Time (typically an unsigned 32-bit
+    // integer) which wraps times outside that range.
+    TimeDuration timeStampDelta = (aTimeStamp - mReferenceTimeStamp);
+    int64_t wholeMillis = static_cast<int64_t>(timeStampDelta.ToMilliseconds());
+    Time wrappedTimeStampDelta = wholeMillis;  // truncate to unsigned
+
+    Time timeToTimeStamp = wrappedTimeStampDelta - timeDelta;
+    bool isNewer = false;
+    if (timeToTimeStamp == 0) {
+      // wholeMillis needs no adjustment
+    } else if (timeToTimeStamp < kTimeHalfRange) {
+      wholeMillis -= timeToTimeStamp;
+    } else {
+      isNewer = true;
+      wholeMillis += (-timeToTimeStamp);
+    }
+    if (aTimeAsTimeStamp) {
+      *aTimeAsTimeStamp =
+          mReferenceTimeStamp + TimeDuration::FromMilliseconds(wholeMillis);
+    }
+
+    return isNewer;
+  }
+
+  Time mReferenceTime;
+  TimeStamp mReferenceTimeStamp;
+  Time mLastBackwardsSkewCheck;
+
+  const Time kTimeRange;
+  const Time kTimeHalfRange;
+  const Time kBackwardsSkewCheckInterval;
+};
+
+}  // namespace mozilla
+
+#endif /* SystemTimeConverter_h */
diff --git a/widget/TextEventDispatcher.cpp b/widget/TextEventDispatcher.cpp
new file mode 100644
index 0000000000..cf414a23e3
--- /dev/null
+++ b/widget/TextEventDispatcher.cpp
@@ -0,0 +1,1043 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TextEventDispatcher.h"
+
+#include "IMEData.h"
+#include "PuppetWidget.h"
+#include "TextEvents.h"
+
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "nsCharTraits.h"
+#include "nsIFrame.h"
+#include "nsIWidget.h"
+#include "nsPIDOMWindow.h"
+#include "nsView.h"
+
+namespace mozilla {
+namespace widget {
+
+/******************************************************************************
+ * TextEventDispatcher
+ *****************************************************************************/
+TextEventDispatcher::TextEventDispatcher(nsIWidget* aWidget)
+    : mWidget(aWidget),
+      mDispatchingEvent(0),
+      mInputTransactionType(eNoInputTransaction),
+      mIsComposing(false),
+      mIsHandlingComposition(false),
+      mHasFocus(false) {
+  MOZ_RELEASE_ASSERT(mWidget, "aWidget must not be nullptr");
+
+  ClearNotificationRequests();
+}
+
+nsresult TextEventDispatcher::BeginInputTransaction(
+    TextEventDispatcherListener* aListener) {
+  return BeginInputTransactionInternal(aListener,
+                                       eSameProcessSyncInputTransaction);
+}
+
+nsresult TextEventDispatcher::BeginTestInputTransaction(
+    TextEventDispatcherListener* aListener, bool aIsAPZAware) {
+  return BeginInputTransactionInternal(
+      aListener, aIsAPZAware ? eAsyncTestInputTransaction
+                             : eSameProcessSyncTestInputTransaction);
+}
+
+nsresult TextEventDispatcher::BeginNativeInputTransaction() {
+  if (NS_WARN_IF(!mWidget)) {
+    return NS_ERROR_FAILURE;
+  }
+  RefPtr<TextEventDispatcherListener> listener =
+      mWidget->GetNativeTextEventDispatcherListener();
+  if (NS_WARN_IF(!listener)) {
+    return NS_ERROR_FAILURE;
+  }
+  return BeginInputTransactionInternal(listener, eNativeInputTransaction);
+}
+
+nsresult TextEventDispatcher::BeginInputTransactionInternal(
+    TextEventDispatcherListener* aListener, InputTransactionType aType) {
+  if (NS_WARN_IF(!aListener)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
+  if (listener) {
+    if (listener == aListener && mInputTransactionType == aType) {
+      UpdateNotificationRequests();
+      return NS_OK;
+    }
+    // If this has composition or is dispatching an event, any other listener
+    // can steal ownership.  Especially, if the latter case is allowed,
+    // nobody cannot begin input transaction with this if a modal dialog is
+    // opened during dispatching an event.
+    if (IsComposing() || IsDispatchingEvent()) {
+      return NS_ERROR_ALREADY_INITIALIZED;
+    }
+  }
+  mListener = do_GetWeakReference(aListener);
+  mInputTransactionType = aType;
+  if (listener && listener != aListener) {
+    listener->OnRemovedFrom(this);
+  }
+  UpdateNotificationRequests();
+  return NS_OK;
+}
+
+nsresult TextEventDispatcher::BeginInputTransactionFor(
+    const WidgetGUIEvent* aEvent, PuppetWidget* aPuppetWidget) {
+  MOZ_ASSERT(XRE_IsContentProcess());
+  MOZ_ASSERT(!IsDispatchingEvent());
+
+  switch (aEvent->mMessage) {
+    case eKeyDown:
+    case eKeyPress:
+    case eKeyUp:
+      MOZ_ASSERT(aEvent->mClass == eKeyboardEventClass);
+      break;
+    case eCompositionStart:
+    case eCompositionChange:
+    case eCompositionCommit:
+    case eCompositionCommitAsIs:
+      MOZ_ASSERT(aEvent->mClass == eCompositionEventClass);
+      break;
+    default:
+      return NS_ERROR_INVALID_ARG;
+  }
+
+  if (aEvent->mFlags.mIsSynthesizedForTests) {
+    // If the event is for an automated test and this instance dispatched
+    // an event to the parent process, we can assume that this is already
+    // initialized properly.
+    if (mInputTransactionType == eAsyncTestInputTransaction) {
+      return NS_OK;
+    }
+    // Even if the event coming from the parent process is synthesized for
+    // tests, this process should treat it as "sync" test here because
+    // it won't be go back to the parent process.
+    nsresult rv = BeginInputTransactionInternal(
+        static_cast<TextEventDispatcherListener*>(aPuppetWidget),
+        eSameProcessSyncTestInputTransaction);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+  } else {
+    nsresult rv = BeginNativeInputTransaction();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+  }
+
+  // Emulate modifying members which indicate the state of composition.
+  // If we need to manage more states and/or more complexly, we should create
+  // internal methods which are called by both here and each event dispatcher
+  // method of this class.
+  switch (aEvent->mMessage) {
+    case eKeyDown:
+    case eKeyPress:
+    case eKeyUp:
+      return NS_OK;
+    case eCompositionStart:
+      MOZ_ASSERT(!mIsComposing);
+      mIsComposing = mIsHandlingComposition = true;
+      return NS_OK;
+    case eCompositionChange:
+      MOZ_ASSERT(mIsComposing);
+      MOZ_ASSERT(mIsHandlingComposition);
+      mIsComposing = mIsHandlingComposition = true;
+      return NS_OK;
+    case eCompositionCommit:
+    case eCompositionCommitAsIs:
+      MOZ_ASSERT(mIsComposing);
+      MOZ_ASSERT(mIsHandlingComposition);
+      mIsComposing = false;
+      mIsHandlingComposition = true;
+      return NS_OK;
+    default:
+      MOZ_ASSERT_UNREACHABLE("You forgot to handle the event");
+      return NS_ERROR_UNEXPECTED;
+  }
+}
+void TextEventDispatcher::EndInputTransaction(
+    TextEventDispatcherListener* aListener) {
+  if (NS_WARN_IF(IsComposing()) || NS_WARN_IF(IsDispatchingEvent())) {
+    return;
+  }
+
+  mInputTransactionType = eNoInputTransaction;
+
+  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
+  if (NS_WARN_IF(!listener)) {
+    return;
+  }
+
+  if (NS_WARN_IF(listener != aListener)) {
+    return;
+  }
+
+  mListener = nullptr;
+  listener->OnRemovedFrom(this);
+  UpdateNotificationRequests();
+}
+
+void TextEventDispatcher::OnDestroyWidget() {
+  mWidget = nullptr;
+  mHasFocus = false;
+  ClearNotificationRequests();
+  mPendingComposition.Clear();
+  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
+  mListener = nullptr;
+  mWritingMode.reset();
+  mInputTransactionType = eNoInputTransaction;
+  if (listener) {
+    listener->OnRemovedFrom(this);
+  }
+}
+
+nsresult TextEventDispatcher::GetState() const {
+  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
+  if (!listener) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  if (!mWidget || mWidget->Destroyed()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+  return NS_OK;
+}
+
+void TextEventDispatcher::InitEvent(WidgetGUIEvent& aEvent) const {
+  aEvent.mRefPoint = LayoutDeviceIntPoint(0, 0);
+  aEvent.mFlags.mIsSynthesizedForTests = IsForTests();
+  if (aEvent.mClass != eCompositionEventClass) {
+    return;
+  }
+  void* pseudoIMEContext = GetPseudoIMEContext();
+  if (pseudoIMEContext) {
+    aEvent.AsCompositionEvent()->mNativeIMEContext.InitWithRawNativeIMEContext(
+        pseudoIMEContext);
+  }
+#ifdef DEBUG
+  else {
+    MOZ_ASSERT(!XRE_IsContentProcess(),
+               "Why did the content process start native event transaction?");
+    MOZ_ASSERT(aEvent.AsCompositionEvent()->mNativeIMEContext.IsValid(),
+               "Native IME context shouldn't be invalid");
+  }
+#endif  // #ifdef DEBUG
+}
+
+Maybe<WritingMode> TextEventDispatcher::MaybeQueryWritingModeAtSelection()
+    const {
+  if (mHasFocus || mWritingMode.isSome()) {
+    return mWritingMode;
+  }
+
+  if (NS_WARN_IF(!mWidget)) {
+    return Nothing();
+  }
+
+  // If a remote content has focus and IME does not have focus, it's going to
+  // fail eQuerySelectedText in ContentCacheParent.  For avoiding to waste
+  // unnecessary runtime cost and to prevent unnecessary warnings, we should
+  // not dispatch the event in the case.
+  const InputContext inputContext = mWidget->GetInputContext();
+  if (XRE_IsE10sParentProcess() && inputContext.IsOriginContentProcess() &&
+      !inputContext.mIMEState.IsEditable()) {
+    return Nothing();
+  }
+
+  WidgetQueryContentEvent querySelectedTextEvent(true, eQuerySelectedText,
+                                                 mWidget);
+  nsEventStatus status = nsEventStatus_eIgnore;
+  const_cast<TextEventDispatcher*>(this)->DispatchEvent(
+      mWidget, querySelectedTextEvent, status);
+  if (!querySelectedTextEvent.FoundSelection()) {
+    return Nothing();
+  }
+
+  return Some(querySelectedTextEvent.mReply->mWritingMode);
+}
+
+nsresult TextEventDispatcher::DispatchEvent(nsIWidget* aWidget,
+                                            WidgetGUIEvent& aEvent,
+                                            nsEventStatus& aStatus) {
+  MOZ_ASSERT(!aEvent.AsInputEvent(), "Use DispatchInputEvent()");
+
+  RefPtr<TextEventDispatcher> kungFuDeathGrip(this);
+  nsCOMPtr<nsIWidget> widget(aWidget);
+  mDispatchingEvent++;
+  nsresult rv = widget->DispatchEvent(&aEvent, aStatus);
+  mDispatchingEvent--;
+  return rv;
+}
+
+nsresult TextEventDispatcher::DispatchInputEvent(nsIWidget* aWidget,
+                                                 WidgetInputEvent& aEvent,
+                                                 nsEventStatus& aStatus) {
+  RefPtr<TextEventDispatcher> kungFuDeathGrip(this);
+  nsCOMPtr<nsIWidget> widget(aWidget);
+  mDispatchingEvent++;
+
+  // If the event is dispatched via nsIWidget::DispatchInputEvent(), it
+  // sends the event to the parent process first since APZ needs to handle it
+  // first.  However, some callers (e.g., keyboard apps on B2G and tests
+  // expecting synchronous dispatch) don't want this to do that.
+  nsresult rv = NS_OK;
+  if (ShouldSendInputEventToAPZ()) {
+    aStatus = widget->DispatchInputEvent(&aEvent).mContentStatus;
+  } else {
+    rv = widget->DispatchEvent(&aEvent, aStatus);
+  }
+
+  mDispatchingEvent--;
+  return rv;
+}
+
+nsresult TextEventDispatcher::StartComposition(
+    nsEventStatus& aStatus, const WidgetEventTime* aEventTime) {
+  aStatus = nsEventStatus_eIgnore;
+
+  nsresult rv = GetState();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (NS_WARN_IF(mIsComposing)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // When you change some members from here, you may need same change in
+  // BeginInputTransactionFor().
+  mIsComposing = mIsHandlingComposition = true;
+  WidgetCompositionEvent compositionStartEvent(true, eCompositionStart,
+                                               mWidget);
+  InitEvent(compositionStartEvent);
+  if (aEventTime) {
+    compositionStartEvent.AssignEventTime(*aEventTime);
+  }
+  rv = DispatchEvent(mWidget, compositionStartEvent, aStatus);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult TextEventDispatcher::StartCompositionAutomaticallyIfNecessary(
+    nsEventStatus& aStatus, const WidgetEventTime* aEventTime) {
+  if (IsComposing()) {
+    return NS_OK;
+  }
+
+  nsresult rv = StartComposition(aStatus, aEventTime);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // If started composition has already been committed, we shouldn't dispatch
+  // the compositionchange event.
+  if (!IsComposing()) {
+    aStatus = nsEventStatus_eConsumeNoDefault;
+    return NS_OK;
+  }
+
+  // Note that the widget might be destroyed during a call of
+  // StartComposition().  In such case, we shouldn't keep dispatching next
+  // event.
+  rv = GetState();
+  if (NS_FAILED(rv)) {
+    MOZ_ASSERT(rv != NS_ERROR_NOT_INITIALIZED,
+               "aDispatcher must still be initialized in this case");
+    aStatus = nsEventStatus_eConsumeNoDefault;
+    return NS_OK;  // Don't throw exception in this case
+  }
+
+  aStatus = nsEventStatus_eIgnore;
+  return NS_OK;
+}
+
+nsresult TextEventDispatcher::CommitComposition(
+    nsEventStatus& aStatus, const nsAString* aCommitString,
+    const WidgetEventTime* aEventTime) {
+  aStatus = nsEventStatus_eIgnore;
+
+  nsresult rv = GetState();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // When there is no composition, caller shouldn't try to commit composition
+  // with non-existing composition string nor commit composition with empty
+  // string.
+  if (NS_WARN_IF(!IsComposing() &&
+                 (!aCommitString || aCommitString->IsEmpty()))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsIWidget> widget(mWidget);
+  rv = StartCompositionAutomaticallyIfNecessary(aStatus, aEventTime);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  if (aStatus == nsEventStatus_eConsumeNoDefault) {
+    return NS_OK;
+  }
+
+  // When you change some members from here, you may need same change in
+  // BeginInputTransactionFor().
+
+  // End current composition and make this free for other IMEs.
+  mIsComposing = false;
+
+  EventMessage message =
+      aCommitString ? eCompositionCommit : eCompositionCommitAsIs;
+  WidgetCompositionEvent compositionCommitEvent(true, message, widget);
+  InitEvent(compositionCommitEvent);
+  if (aEventTime) {
+    compositionCommitEvent.AssignEventTime(*aEventTime);
+  }
+  if (message == eCompositionCommit) {
+    compositionCommitEvent.mData = *aCommitString;
+    // If aCommitString comes from TextInputProcessor, it may be void, but
+    // editor requires non-void string even when it's empty.
+    compositionCommitEvent.mData.SetIsVoid(false);
+    // Don't send CRLF nor CR, replace it with LF here.
+    compositionCommitEvent.mData.ReplaceSubstring(u"\r\n"_ns, u"\n"_ns);
+    compositionCommitEvent.mData.ReplaceSubstring(u"\r"_ns, u"\n"_ns);
+  }
+  rv = DispatchEvent(widget, compositionCommitEvent, aStatus);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult TextEventDispatcher::NotifyIME(
+    const IMENotification& aIMENotification) {
+  nsresult rv = NS_ERROR_NOT_IMPLEMENTED;
+
+  switch (aIMENotification.mMessage) {
+    case NOTIFY_IME_OF_FOCUS: {
+      mWritingMode = MaybeQueryWritingModeAtSelection();
+      break;
+    }
+    case NOTIFY_IME_OF_BLUR:
+      mHasFocus = false;
+      mWritingMode.reset();
+      ClearNotificationRequests();
+      break;
+    case NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED:
+      // If content handles composition events when native IME doesn't have
+      // composition, that means that we completely finished handling
+      // composition(s).  Note that when focused content is in a remote
+      // process, this is sent when all dispatched composition events
+      // have been handled in the remote process.
+      if (!IsComposing()) {
+        mIsHandlingComposition = false;
+      }
+      break;
+    case NOTIFY_IME_OF_SELECTION_CHANGE:
+      if (mHasFocus && aIMENotification.mSelectionChangeData.HasRange()) {
+        mWritingMode =
+            Some(aIMENotification.mSelectionChangeData.GetWritingMode());
+      }
+      break;
+    default:
+      break;
+  }
+
+  // First, send the notification to current input transaction's listener.
+  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
+  if (listener) {
+    rv = listener->NotifyIME(this, aIMENotification);
+  }
+
+  if (!mWidget) {
+    return rv;
+  }
+
+  // If current input transaction isn't for native event handler, we should
+  // send the notification to the native text event dispatcher listener
+  // since native event handler may need to do something from
+  // TextEventDispatcherListener::NotifyIME() even before there is no
+  // input transaction yet.  For example, native IME handler may need to
+  // create new context at receiving NOTIFY_IME_OF_FOCUS.  In this case,
+  // mListener may not be initialized since input transaction should be
+  // initialized immediately before dispatching every WidgetKeyboardEvent
+  // and WidgetCompositionEvent (dispatching events always occurs after
+  // focus move).
+  nsCOMPtr<TextEventDispatcherListener> nativeListener =
+      mWidget->GetNativeTextEventDispatcherListener();
+  if (listener != nativeListener && nativeListener) {
+    switch (aIMENotification.mMessage) {
+      case REQUEST_TO_COMMIT_COMPOSITION:
+      case REQUEST_TO_CANCEL_COMPOSITION:
+        // It's not necessary to notify native IME of requests.
+        break;
+      default: {
+        // Even if current input transaction's listener returns NS_OK or
+        // something, we need to notify native IME of notifications because
+        // when user typing after TIP does something, the changed information
+        // is necessary for them.
+        nsresult rv2 = nativeListener->NotifyIME(this, aIMENotification);
+        // But return the result from current listener except when the
+        // notification isn't handled.
+        if (rv == NS_ERROR_NOT_IMPLEMENTED) {
+          rv = rv2;
+        }
+        break;
+      }
+    }
+  }
+
+  if (aIMENotification.mMessage == NOTIFY_IME_OF_FOCUS) {
+    mHasFocus = true;
+    UpdateNotificationRequests();
+  }
+
+  return rv;
+}
+
+void TextEventDispatcher::ClearNotificationRequests() {
+  mIMENotificationRequests = IMENotificationRequests();
+}
+
+void TextEventDispatcher::UpdateNotificationRequests() {
+  ClearNotificationRequests();
+
+  // If it doesn't has focus, no notifications are available.
+  if (!mHasFocus || !mWidget) {
+    return;
+  }
+
+  // If there is a listener, its requests are necessary.
+  nsCOMPtr<TextEventDispatcherListener> listener = do_QueryReferent(mListener);
+  if (listener) {
+    mIMENotificationRequests = listener->GetIMENotificationRequests();
+  }
+
+  // Even if this is in non-native input transaction, native IME needs
+  // requests.  So, add native IME requests too.
+  if (!IsInNativeInputTransaction()) {
+    nsCOMPtr<TextEventDispatcherListener> nativeListener =
+        mWidget->GetNativeTextEventDispatcherListener();
+    if (nativeListener) {
+      mIMENotificationRequests |= nativeListener->GetIMENotificationRequests();
+    }
+  }
+}
+
+bool TextEventDispatcher::DispatchKeyboardEvent(
+    EventMessage aMessage, const WidgetKeyboardEvent& aKeyboardEvent,
+    nsEventStatus& aStatus, void* aData) {
+  return DispatchKeyboardEventInternal(aMessage, aKeyboardEvent, aStatus,
+                                       aData);
+}
+
+bool TextEventDispatcher::DispatchKeyboardEventInternal(
+    EventMessage aMessage, const WidgetKeyboardEvent& aKeyboardEvent,
+    nsEventStatus& aStatus, void* aData, uint32_t aIndexOfKeypress,
+    bool aNeedsCallback) {
+  // Note that this method is also used for dispatching key events on a plugin
+  // because key events on a plugin should be dispatched same as normal key
+  // events.  Then, only some handlers which need to intercept key events
+  // before the focused plugin (e.g., reserved shortcut key handlers) can
+  // consume the events.
+  MOZ_ASSERT(
+      aMessage == eKeyDown || aMessage == eKeyUp || aMessage == eKeyPress,
+      "Invalid aMessage value");
+  nsresult rv = GetState();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+
+  // If the key shouldn't cause keypress events, don't this patch them.
+  if (aMessage == eKeyPress && !aKeyboardEvent.ShouldCauseKeypressEvents()) {
+    return false;
+  }
+
+  // Basically, key events shouldn't be dispatched during composition.
+  // Note that plugin process has different IME context.  Therefore, we don't
+  // need to check our composition state when the key event is fired on a
+  // plugin.
+  if (IsComposing()) {
+    // However, if we need to behave like other browsers, we need the keydown
+    // and keyup events.  Note that this behavior is also allowed by D3E spec.
+    // FYI: keypress events must not be fired during composition.
+    if (!StaticPrefs::dom_keyboardevent_dispatch_during_composition() ||
+        aMessage == eKeyPress) {
+      return false;
+    }
+    // XXX If there was mOnlyContentDispatch for this case, it might be useful
+    //     because our chrome doesn't assume that key events are fired during
+    //     composition.
+  }
+
+  WidgetKeyboardEvent keyEvent(true, aMessage, mWidget);
+  InitEvent(keyEvent);
+  keyEvent.AssignKeyEventData(aKeyboardEvent, false);
+  // Command arrays are not duplicated by AssignKeyEventData() due to
+  // both performance and footprint reasons.  So, when TextInputProcessor
+  // emulates real text input or synthesizing keyboard events for tests,
+  // the arrays may be initialized all commands already.  If so, we need to
+  // duplicate the arrays here, but we should do this only when we're
+  // dispatching eKeyPress events because BrowserParent::SendRealKeyEvent()
+  // does this only for eKeyPress event.  Note that this is not required if
+  // we're in the main process because in the parent process, the edit commands
+  // will be initialized by `ExecuteEditCommands()` (when the event is handled
+  // by editor event listener) or `InitAllEditCommands()` (when the event is
+  // set to a content process).  We should test whether these pathes work or
+  // not too.
+  if (XRE_IsContentProcess() && keyEvent.mIsSynthesizedByTIP) {
+    if (aMessage == eKeyPress) {
+      keyEvent.AssignCommands(aKeyboardEvent);
+    } else {
+      // Prevent retriving native edit commands if we're in a content process
+      // because only `eKeyPress` events coming from the main process have
+      // edit commands (See `BrowserParent::SendRealKeyEvent`).  And also
+      // retriving edit commands from a content process requires synchonous
+      // IPC and that makes running tests slower.  Therefore, we should mark
+      // the `eKeyPress` event does not need to retrieve edit commands anymore.
+      keyEvent.PreventNativeKeyBindings();
+    }
+  }
+
+  if (aStatus == nsEventStatus_eConsumeNoDefault) {
+    // If the key event should be dispatched as consumed event, marking it here.
+    // This is useful to prevent double action.  This is intended to the system
+    // has already consumed the event but we need to dispatch the event for
+    // compatibility with older version and other browsers.  So, we should not
+    // stop cross process forwarding of them.
+    keyEvent.PreventDefaultBeforeDispatch(CrossProcessForwarding::eAllow);
+  }
+
+  // Corrects each member for the specific key event type.
+  if (keyEvent.mKeyNameIndex != KEY_NAME_INDEX_USE_STRING) {
+    MOZ_ASSERT(!aIndexOfKeypress,
+               "aIndexOfKeypress must be 0 for non-printable key");
+    // If the keyboard event isn't caused by printable key, its charCode should
+    // be 0.
+    keyEvent.SetCharCode(0);
+  } else {
+    MOZ_DIAGNOSTIC_ASSERT_IF(aMessage == eKeyDown || aMessage == eKeyUp,
+                             !aIndexOfKeypress);
+    MOZ_DIAGNOSTIC_ASSERT_IF(
+        aMessage == eKeyPress,
+        aIndexOfKeypress < std::max<size_t>(keyEvent.mKeyValue.Length(), 1));
+    char16_t ch =
+        keyEvent.mKeyValue.IsEmpty() ? 0 : keyEvent.mKeyValue[aIndexOfKeypress];
+    keyEvent.SetCharCode(static_cast<uint32_t>(ch));
+    if (aMessage == eKeyPress) {
+      // keyCode of eKeyPress events of printable keys should be always 0.
+      keyEvent.mKeyCode = 0;
+      // eKeyPress events are dispatched for every character.
+      // So, each key value of eKeyPress events should be a character.
+      if (ch) {
+        if (!IS_SURROGATE(ch)) {
+          keyEvent.mKeyValue.Assign(ch);
+        } else {
+          const bool isHighSurrogateFollowedByLowSurrogate =
+              aIndexOfKeypress + 1 < keyEvent.mKeyValue.Length() &&
+              NS_IS_HIGH_SURROGATE(ch) &&
+              NS_IS_LOW_SURROGATE(keyEvent.mKeyValue[aIndexOfKeypress + 1]);
+          const bool isLowSurrogateFollowingHighSurrogate =
+              !isHighSurrogateFollowedByLowSurrogate && aIndexOfKeypress > 0 &&
+              NS_IS_LOW_SURROGATE(ch) &&
+              NS_IS_HIGH_SURROGATE(keyEvent.mKeyValue[aIndexOfKeypress - 1]);
+          NS_WARNING_ASSERTION(isHighSurrogateFollowedByLowSurrogate ||
+                                   isLowSurrogateFollowingHighSurrogate,
+                               "Lone surrogate input should not happen");
+          if (StaticPrefs::
+                  dom_event_keypress_dispatch_once_per_surrogate_pair()) {
+            if (isHighSurrogateFollowedByLowSurrogate) {
+              keyEvent.mKeyValue.Assign(
+                  keyEvent.mKeyValue.BeginReading() + aIndexOfKeypress, 2);
+              keyEvent.SetCharCode(
+                  SURROGATE_TO_UCS4(ch, keyEvent.mKeyValue[1]));
+            } else if (isLowSurrogateFollowingHighSurrogate) {
+              // Although not dispatching eKeyPress event (because it's already
+              // dispatched for the low surrogate above), the caller should
+              // treat that this dispatched eKeyPress event normally so that
+              // return true here.
+              return true;
+            }
+            // Do not expose ill-formed UTF-16 string because it's a
+            // problematic for Rust-running-as-wasm for example.
+            else {
+              keyEvent.mKeyValue.Truncate();
+            }
+          } else if (!StaticPrefs::
+                         dom_event_keypress_key_allow_lone_surrogate()) {
+            // If it's a high surrogate followed by a low surrogate, we should
+            // expose the surrogate pair with .key value.
+            if (isHighSurrogateFollowedByLowSurrogate) {
+              keyEvent.mKeyValue.Assign(
+                  keyEvent.mKeyValue.BeginReading() + aIndexOfKeypress, 2);
+            }
+            // Do not expose low surrogate which should be handled by the
+            // preceding keypress event.  And also do not expose ill-formed
+            // UTF-16 because it's a problematic for Rust-running-as-wasm for
+            // example.
+            else {
+              keyEvent.mKeyValue.Truncate();
+            }
+          } else {
+            // Here is a path for traditional behavior. We set `.key` to
+            // high-surrogate and low-surrogate separately.
+            keyEvent.mKeyValue.Assign(ch);
+          }
+        }
+      } else {
+        keyEvent.mKeyValue.Truncate();
+      }
+    }
+  }
+  if (aMessage == eKeyUp) {
+    // mIsRepeat of keyup event must be false.
+    keyEvent.mIsRepeat = false;
+  }
+  // mIsComposing should be initialized later.
+  keyEvent.mIsComposing = false;
+  if (mInputTransactionType == eNativeInputTransaction) {
+    // Copy mNativeKeyEvent here because for safety for other users of
+    // AssignKeyEventData(), it doesn't copy this.
+    keyEvent.mNativeKeyEvent = aKeyboardEvent.mNativeKeyEvent;
+  } else {
+    // If it's not a keyboard event for native key event, we should ensure that
+    // mNativeKeyEvent is null.
+    keyEvent.mNativeKeyEvent = nullptr;
+  }
+  // TODO: Manage mUniqueId here.
+
+  // Request the alternative char codes for the key event.
+  // eKeyDown also needs alternative char codes because nsXBLWindowKeyHandler
+  // needs to check if a following keypress event is reserved by chrome for
+  // stopping propagation of its preceding keydown event.
+  keyEvent.mAlternativeCharCodes.Clear();
+  if ((aMessage == eKeyDown || aMessage == eKeyPress) &&
+      (aNeedsCallback || keyEvent.IsControl() || keyEvent.IsAlt() ||
+       keyEvent.IsMeta())) {
+    nsCOMPtr<TextEventDispatcherListener> listener =
+        do_QueryReferent(mListener);
+    if (listener) {
+      DebugOnly<WidgetKeyboardEvent> original(keyEvent);
+      listener->WillDispatchKeyboardEvent(this, keyEvent, aIndexOfKeypress,
+                                          aData);
+      MOZ_ASSERT(keyEvent.mMessage ==
+                 static_cast<WidgetKeyboardEvent&>(original).mMessage);
+      MOZ_ASSERT(keyEvent.mKeyCode ==
+                 static_cast<WidgetKeyboardEvent&>(original).mKeyCode);
+      MOZ_ASSERT(keyEvent.mLocation ==
+                 static_cast<WidgetKeyboardEvent&>(original).mLocation);
+      MOZ_ASSERT(keyEvent.mIsRepeat ==
+                 static_cast<WidgetKeyboardEvent&>(original).mIsRepeat);
+      MOZ_ASSERT(keyEvent.mIsComposing ==
+                 static_cast<WidgetKeyboardEvent&>(original).mIsComposing);
+      MOZ_ASSERT(keyEvent.mKeyNameIndex ==
+                 static_cast<WidgetKeyboardEvent&>(original).mKeyNameIndex);
+      MOZ_ASSERT(keyEvent.mCodeNameIndex ==
+                 static_cast<WidgetKeyboardEvent&>(original).mCodeNameIndex);
+      MOZ_ASSERT(keyEvent.mKeyValue ==
+                 static_cast<WidgetKeyboardEvent&>(original).mKeyValue);
+      MOZ_ASSERT(keyEvent.mCodeValue ==
+                 static_cast<WidgetKeyboardEvent&>(original).mCodeValue);
+    }
+  }
+
+  if (StaticPrefs::
+          dom_keyboardevent_keypress_dispatch_non_printable_keys_only_system_group_in_content() &&
+      keyEvent.mMessage == eKeyPress &&
+      !keyEvent.ShouldKeyPressEventBeFiredOnContent()) {
+    // Note that even if we set it to true, this may be overwritten by
+    // PresShell::DispatchEventToDOM().
+    keyEvent.mFlags.mOnlySystemGroupDispatchInContent = true;
+  }
+
+  // If an editable element has focus and we're in the parent process, we should
+  // retrieve native key bindings right now because even if it matches with a
+  // reserved shortcut key, it should be handled by the editor.
+  if (XRE_IsParentProcess() && mHasFocus &&
+      (aMessage == eKeyDown || aMessage == eKeyPress)) {
+    keyEvent.InitAllEditCommands(mWritingMode);
+  }
+
+  DispatchInputEvent(mWidget, keyEvent, aStatus);
+  return true;
+}
+
+bool TextEventDispatcher::MaybeDispatchKeypressEvents(
+    const WidgetKeyboardEvent& aKeyboardEvent, nsEventStatus& aStatus,
+    void* aData, bool aNeedsCallback) {
+  // If the key event was consumed, keypress event shouldn't be fired.
+  if (aStatus == nsEventStatus_eConsumeNoDefault) {
+    return false;
+  }
+
+  // If the key shouldn't cause keypress events, don't fire them.
+  if (!aKeyboardEvent.ShouldCauseKeypressEvents()) {
+    return false;
+  }
+
+  // If the key isn't a printable key or just inputting one character or
+  // no character, we should dispatch only one keypress.  Otherwise, i.e.,
+  // if the key is a printable key and inputs multiple characters, keypress
+  // event should be dispatched the count of inputting characters times.
+  size_t keypressCount =
+      aKeyboardEvent.mKeyNameIndex != KEY_NAME_INDEX_USE_STRING
+          ? 1
+          : std::max(static_cast<nsAString::size_type>(1),
+                     aKeyboardEvent.mKeyValue.Length());
+  bool isDispatched = false;
+  bool consumed = false;
+  for (size_t i = 0; i < keypressCount; i++) {
+    aStatus = nsEventStatus_eIgnore;
+    if (!DispatchKeyboardEventInternal(eKeyPress, aKeyboardEvent, aStatus,
+                                       aData, i, aNeedsCallback)) {
+      // The widget must have been gone.
+      break;
+    }
+    isDispatched = true;
+    if (!consumed) {
+      consumed = (aStatus == nsEventStatus_eConsumeNoDefault);
+    }
+  }
+
+  // If one of the keypress event was consumed, return ConsumeNoDefault.
+  if (consumed) {
+    aStatus = nsEventStatus_eConsumeNoDefault;
+  }
+
+  return isDispatched;
+}
+
+/******************************************************************************
+ * TextEventDispatcher::PendingComposition
+ *****************************************************************************/
+
+TextEventDispatcher::PendingComposition::PendingComposition() { Clear(); }
+
+void TextEventDispatcher::PendingComposition::Clear() {
+  mString.Truncate();
+  mClauses = nullptr;
+  mCaret.mRangeType = TextRangeType::eUninitialized;
+  mReplacedNativeLineBreakers = false;
+}
+
+void TextEventDispatcher::PendingComposition::EnsureClauseArray() {
+  if (mClauses) {
+    return;
+  }
+  mClauses = new TextRangeArray();
+}
+
+nsresult TextEventDispatcher::PendingComposition::SetString(
+    const nsAString& aString) {
+  MOZ_ASSERT(!mReplacedNativeLineBreakers);
+  mString = aString;
+  return NS_OK;
+}
+
+nsresult TextEventDispatcher::PendingComposition::AppendClause(
+    uint32_t aLength, TextRangeType aTextRangeType) {
+  MOZ_ASSERT(!mReplacedNativeLineBreakers);
+
+  if (NS_WARN_IF(!aLength)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  switch (aTextRangeType) {
+    case TextRangeType::eRawClause:
+    case TextRangeType::eSelectedRawClause:
+    case TextRangeType::eConvertedClause:
+    case TextRangeType::eSelectedClause: {
+      EnsureClauseArray();
+      TextRange textRange;
+      textRange.mStartOffset =
+          mClauses->IsEmpty() ? 0 : mClauses->LastElement().mEndOffset;
+      textRange.mEndOffset = textRange.mStartOffset + aLength;
+      textRange.mRangeType = aTextRangeType;
+      mClauses->AppendElement(textRange);
+      return NS_OK;
+    }
+    default:
+      return NS_ERROR_INVALID_ARG;
+  }
+}
+
+nsresult TextEventDispatcher::PendingComposition::SetCaret(uint32_t aOffset,
+                                                           uint32_t aLength) {
+  MOZ_ASSERT(!mReplacedNativeLineBreakers);
+
+  mCaret.mStartOffset = aOffset;
+  mCaret.mEndOffset = mCaret.mStartOffset + aLength;
+  mCaret.mRangeType = TextRangeType::eCaret;
+  return NS_OK;
+}
+
+nsresult TextEventDispatcher::PendingComposition::Set(
+    const nsAString& aString, const TextRangeArray* aRanges) {
+  Clear();
+
+  nsresult rv = SetString(aString);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (!aRanges || aRanges->IsEmpty()) {
+    // Create dummy range if mString isn't empty.
+    if (!mString.IsEmpty()) {
+      rv = AppendClause(mString.Length(), TextRangeType::eRawClause);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+      ReplaceNativeLineBreakers();
+    }
+    return NS_OK;
+  }
+
+  // Adjust offsets in the ranges for XP linefeed character (only \n).
+  for (uint32_t i = 0; i < aRanges->Length(); ++i) {
+    TextRange range = aRanges->ElementAt(i);
+    if (range.mRangeType == TextRangeType::eCaret) {
+      mCaret = range;
+    } else {
+      EnsureClauseArray();
+      mClauses->AppendElement(range);
+    }
+  }
+  ReplaceNativeLineBreakers();
+  return NS_OK;
+}
+
+void TextEventDispatcher::PendingComposition::ReplaceNativeLineBreakers() {
+  mReplacedNativeLineBreakers = true;
+
+  // If the composition string is empty, we don't need to do anything.
+  if (mString.IsEmpty()) {
+    return;
+  }
+
+  nsAutoString nativeString(mString);
+  // Don't expose CRLF nor CR to web contents, instead, use LF.
+  mString.ReplaceSubstring(u"\r\n"_ns, u"\n"_ns);
+  mString.ReplaceSubstring(u"\r"_ns, u"\n"_ns);
+
+  // If the length isn't changed, we don't need to adjust any offset and length
+  // of mClauses nor mCaret.
+  if (nativeString.Length() == mString.Length()) {
+    return;
+  }
+
+  if (mClauses) {
+    for (TextRange& clause : *mClauses) {
+      AdjustRange(clause, nativeString);
+    }
+  }
+  if (mCaret.mRangeType == TextRangeType::eCaret) {
+    AdjustRange(mCaret, nativeString);
+  }
+}
+
+// static
+void TextEventDispatcher::PendingComposition::AdjustRange(
+    TextRange& aRange, const nsAString& aNativeString) {
+  TextRange nativeRange = aRange;
+  // XXX Following code wastes runtime cost because this causes computing
+  //     mStartOffset for each clause from the start of composition string.
+  //     If we'd make TextRange have only its length, we don't need to do
+  //     this.  However, this must not be so serious problem because
+  //     composition string is usually short and separated as a few clauses.
+  if (nativeRange.mStartOffset > 0) {
+    nsAutoString preText(Substring(aNativeString, 0, nativeRange.mStartOffset));
+    preText.ReplaceSubstring(u"\r\n"_ns, u"\n"_ns);
+    aRange.mStartOffset = preText.Length();
+  }
+  if (nativeRange.Length() == 0) {
+    aRange.mEndOffset = aRange.mStartOffset;
+  } else {
+    nsAutoString clause(Substring(aNativeString, nativeRange.mStartOffset,
+                                  nativeRange.Length()));
+    clause.ReplaceSubstring(u"\r\n"_ns, u"\n"_ns);
+    aRange.mEndOffset = aRange.mStartOffset + clause.Length();
+  }
+}
+
+nsresult TextEventDispatcher::PendingComposition::Flush(
+    TextEventDispatcher* aDispatcher, nsEventStatus& aStatus,
+    const WidgetEventTime* aEventTime) {
+  aStatus = nsEventStatus_eIgnore;
+
+  nsresult rv = aDispatcher->GetState();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (mClauses && !mClauses->IsEmpty() &&
+      mClauses->LastElement().mEndOffset != mString.Length()) {
+    NS_WARNING(
+        "Sum of length of the all clauses must be same as the string "
+        "length");
+    Clear();
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+  if (mCaret.mRangeType == TextRangeType::eCaret) {
+    if (mCaret.mEndOffset > mString.Length()) {
+      NS_WARNING("Caret position is out of the composition string");
+      Clear();
+      return NS_ERROR_ILLEGAL_VALUE;
+    }
+    EnsureClauseArray();
+    mClauses->AppendElement(mCaret);
+  }
+
+  // If the composition string is set without Set(), we need to replace native
+  // line breakers in the composition string with XP line breaker.
+  if (!mReplacedNativeLineBreakers) {
+    ReplaceNativeLineBreakers();
+  }
+
+  RefPtr<TextEventDispatcher> kungFuDeathGrip(aDispatcher);
+  nsCOMPtr<nsIWidget> widget(aDispatcher->mWidget);
+  WidgetCompositionEvent compChangeEvent(true, eCompositionChange, widget);
+  aDispatcher->InitEvent(compChangeEvent);
+  if (aEventTime) {
+    compChangeEvent.AssignEventTime(*aEventTime);
+  }
+  compChangeEvent.mData = mString;
+  // If mString comes from TextInputProcessor, it may be void, but editor
+  // requires non-void string even when it's empty.
+  compChangeEvent.mData.SetIsVoid(false);
+  if (mClauses) {
+    MOZ_ASSERT(!mClauses->IsEmpty(),
+               "mClauses must be non-empty array when it's not nullptr");
+    compChangeEvent.mRanges = mClauses;
+  }
+
+  // While this method dispatches a composition event, some other event handler
+  // cause more clauses to be added.  So, we should clear pending composition
+  // before dispatching the event.
+  Clear();
+
+  rv = aDispatcher->StartCompositionAutomaticallyIfNecessary(aStatus,
+                                                             aEventTime);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  if (aStatus == nsEventStatus_eConsumeNoDefault) {
+    return NS_OK;
+  }
+  rv = aDispatcher->DispatchEvent(widget, compChangeEvent, aStatus);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/TextEventDispatcher.h b/widget/TextEventDispatcher.h
new file mode 100644
index 0000000000..6ab131f079
--- /dev/null
+++ b/widget/TextEventDispatcher.h
@@ -0,0 +1,568 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_textcompositionsynthesizer_h_
+#define mozilla_textcompositionsynthesizer_h_
+
+#include "mozilla/RefPtr.h"
+#include "nsString.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/TextEventDispatcherListener.h"
+#include "mozilla/TextRange.h"
+#include "mozilla/widget/IMEData.h"
+#include "WritingModes.h"
+
+class nsIWidget;
+
+namespace mozilla {
+namespace widget {
+
+class PuppetWidget;
+
+/**
+ * TextEventDispatcher is a helper class for dispatching widget events defined
+ * in TextEvents.h.  Currently, this is a helper for dispatching
+ * WidgetCompositionEvent and WidgetKeyboardEvent.  This manages the behavior
+ * of them for conforming to DOM Level 3 Events.
+ * An instance of this class is created by nsIWidget instance and owned by it.
+ * This is typically created only by the top level widgets because only they
+ * handle IME.
+ */
+
+class TextEventDispatcher final {
+  ~TextEventDispatcher() = default;
+
+  NS_INLINE_DECL_REFCOUNTING(TextEventDispatcher)
+
+ public:
+  explicit TextEventDispatcher(nsIWidget* aWidget);
+
+  /**
+   * Initializes the instance for IME or automated test.  Either IME or tests
+   * need to call one of them before starting composition.  If they return
+   * NS_ERROR_ALREADY_INITIALIZED, it means that the listener already listens
+   * notifications from TextEventDispatcher for same purpose (for IME or tests).
+   * If this returns another error, the caller shouldn't keep starting
+   * composition.
+   *
+   * @param aListener       Specify the listener to listen notifications and
+   *                        requests.  This must not be null.
+   *                        NOTE: aListener is stored as weak reference in
+   *                              TextEventDispatcher.  See mListener
+   *                              definition below.
+   */
+  nsresult BeginInputTransaction(TextEventDispatcherListener* aListener);
+  nsresult BeginTestInputTransaction(TextEventDispatcherListener* aListener,
+                                     bool aIsAPZAware);
+  nsresult BeginNativeInputTransaction();
+
+  /**
+   * BeginInputTransactionFor() should be used when aPuppetWidget dispatches
+   * a composition or keyboard event coming from its parent process.
+   */
+  nsresult BeginInputTransactionFor(const WidgetGUIEvent* aEvent,
+                                    PuppetWidget* aPuppetWidget);
+
+  /**
+   * EndInputTransaction() should be called when the listener stops using
+   * the TextEventDispatcher.
+   *
+   * @param aListener       The listener using the TextEventDispatcher instance.
+   */
+  void EndInputTransaction(TextEventDispatcherListener* aListener);
+
+  /**
+   * OnDestroyWidget() is called when mWidget is being destroyed.
+   */
+  void OnDestroyWidget();
+
+  nsIWidget* GetWidget() const { return mWidget; }
+
+  /**
+   * Return true starting from ending handling focus notification and until
+   * receiving blur notification.
+   */
+  bool HasFocus() const { return mHasFocus; }
+
+  const IMENotificationRequests& IMENotificationRequestsRef() const {
+    return mIMENotificationRequests;
+  }
+
+  /**
+   * OnWidgetChangeIMENotificationRequests() is called when aWidget's
+   * IMENotificationRequest is maybe modified by unusual path.  E.g.,
+   * modified in an async path.
+   */
+  void OnWidgetChangeIMENotificationRequests(nsIWidget* aWidget) {
+    MOZ_ASSERT(aWidget);
+    if (mWidget == aWidget) {
+      UpdateNotificationRequests();
+    }
+  }
+
+  /**
+   * GetState() returns current state of this class.
+   *
+   * @return        NS_OK: Fine to compose text.
+   *                NS_ERROR_NOT_INITIALIZED: BeginInputTransaction() or
+   *                                          BeginInputTransactionForTests()
+   *                                          should be called.
+   *                NS_ERROR_NOT_AVAILABLE: The widget isn't available for
+   *                                        composition.
+   */
+  nsresult GetState() const;
+
+  /**
+   * IsComposing() returns true after calling StartComposition() and before
+   * calling CommitComposition().  In other words, native IME has composition
+   * when this returns true.
+   */
+  bool IsComposing() const { return mIsComposing; }
+
+  /**
+   * IsHandlingComposition() returns true after calling StartComposition() and
+   * content has not handled eCompositionCommit(AsIs) event.  In other words,
+   * our content has composition when this returns true.
+   */
+  bool IsHandlingComposition() const { return mIsHandlingComposition; }
+
+  /**
+   * IsInNativeInputTransaction() returns true if native IME handler began a
+   * transaction and it's not finished yet.
+   */
+  bool IsInNativeInputTransaction() const {
+    return mInputTransactionType == eNativeInputTransaction;
+  }
+
+  /**
+   * IsDispatchingEvent() returns true while this instance dispatching an event.
+   */
+  bool IsDispatchingEvent() const { return mDispatchingEvent > 0; }
+
+  /**
+   * GetPseudoIMEContext() returns pseudo native IME context if there is an
+   * input transaction whose type is not for native event handler.
+   * Otherwise, returns nullptr.
+   */
+  void* GetPseudoIMEContext() const {
+    if (mInputTransactionType == eNoInputTransaction ||
+        mInputTransactionType == eNativeInputTransaction) {
+      return nullptr;
+    }
+    return const_cast<TextEventDispatcher*>(this);
+  }
+
+  /**
+   * Return writing mode at selection while this has focus.  Otherwise, or
+   * never exists selection ranges, this returns Nothing.
+   */
+  const Maybe<WritingMode>& MaybeWritingModeRefAtSelection() const {
+    return mWritingMode;
+  }
+
+  /**
+   * MaybeQueryWritingModeAtSelection() returns writing mode at current
+   * selection even if this does not have focus.  If this is not focused, this
+   * queries selection.  Then, chrome script can run due to flushing the layout
+   * if an element in chrome has focus (but it should not cause any problem
+   * hopefully).
+   */
+  MOZ_CAN_RUN_SCRIPT Maybe<WritingMode> MaybeQueryWritingModeAtSelection()
+      const;
+
+  /**
+   * StartComposition() starts composition explicitly.
+   *
+   * @param aEventTime  If this is not nullptr, WidgetCompositionEvent will
+   *                    be initialized with this.  Otherwise, initialized
+   *                    with the time at initializing.
+   */
+  nsresult StartComposition(nsEventStatus& aStatus,
+                            const WidgetEventTime* aEventTime = nullptr);
+
+  /**
+   * CommitComposition() commits composition.
+   *
+   * @param aCommitString   If this is null, commits with the last composition
+   *                        string.  Otherwise, commits the composition with
+   *                        this value.
+   * @param aEventTime      If this is not nullptr, WidgetCompositionEvent will
+   *                        be initialized with this.  Otherwise, initialized
+   *                        with the time at initializing.
+   */
+  nsresult CommitComposition(nsEventStatus& aStatus,
+                             const nsAString* aCommitString = nullptr,
+                             const WidgetEventTime* aEventTime = nullptr);
+
+  /**
+   * SetPendingCompositionString() sets new composition string which will be
+   * dispatched with eCompositionChange event by calling Flush().
+   *
+   * @param aString         New composition string.
+   */
+  nsresult SetPendingCompositionString(const nsAString& aString) {
+    return mPendingComposition.SetString(aString);
+  }
+
+  /**
+   * AppendClauseToPendingComposition() appends a clause information to
+   * the pending composition string.
+   *
+   * @param aLength         Length of the clause.
+   * @param aTextRangeType  One of TextRangeType::eRawClause,
+   *                        TextRangeType::eSelectedRawClause,
+   *                        TextRangeType::eConvertedClause or
+   *                        TextRangeType::eSelectedClause.
+   */
+  nsresult AppendClauseToPendingComposition(uint32_t aLength,
+                                            TextRangeType aTextRangeType) {
+    return mPendingComposition.AppendClause(aLength, aTextRangeType);
+  }
+
+  /**
+   * SetCaretInPendingComposition() sets caret position in the pending
+   * composition string and its length.  This is optional.  If IME doesn't
+   * want to show caret, it shouldn't need to call this.
+   *
+   * @param aOffset         Offset of the caret in the pending composition
+   *                        string.  This should not be larger than the length
+   *                        of the pending composition string.
+   * @param aLength         Caret width.  If this is 0, caret will be collapsed.
+   *                        Note that Gecko doesn't supported wide caret yet,
+   *                        therefore, this is ignored for now.
+   */
+  nsresult SetCaretInPendingComposition(uint32_t aOffset, uint32_t aLength) {
+    return mPendingComposition.SetCaret(aOffset, aLength);
+  }
+
+  /**
+   * SetPendingComposition() is useful if native IME handler already creates
+   * array of clauses and/or caret information.
+   *
+   * @param aString         Composition string.  This may include native line
+   *                        breakers since they will be replaced with XP line
+   *                        breakers automatically.
+   * @param aRanges         This should include the ranges of clauses and/or
+   *                        a range of caret.  Note that this method allows
+   *                        some ranges overlap each other and the range order
+   *                        is not from start to end.
+   */
+  nsresult SetPendingComposition(const nsAString& aString,
+                                 const TextRangeArray* aRanges) {
+    return mPendingComposition.Set(aString, aRanges);
+  }
+
+  /**
+   * FlushPendingComposition() sends the pending composition string
+   * to the widget of the store DOM window.  Before calling this, IME needs to
+   * set pending composition string with SetPendingCompositionString(),
+   * AppendClauseToPendingComposition() and/or
+   * SetCaretInPendingComposition().
+   *
+   * @param aEventTime      If this is not nullptr, WidgetCompositionEvent will
+   *                        be initialized with this.  Otherwise, initialized
+   *                        with the time at initializing.
+   */
+  nsresult FlushPendingComposition(
+      nsEventStatus& aStatus, const WidgetEventTime* aEventTime = nullptr) {
+    return mPendingComposition.Flush(this, aStatus, aEventTime);
+  }
+
+  /**
+   * ClearPendingComposition() makes this instance forget pending composition.
+   */
+  void ClearPendingComposition() { mPendingComposition.Clear(); }
+
+  /**
+   * GetPendingCompositionClauses() returns text ranges which was appended by
+   * AppendClauseToPendingComposition() or SetPendingComposition().
+   */
+  const TextRangeArray* GetPendingCompositionClauses() const {
+    return mPendingComposition.GetClauses();
+  }
+
+  /**
+   * @see nsIWidget::NotifyIME()
+   */
+  // Calling NotifyIME may call OS's API so that everything could happen.
+  // We should mark it MOZ_CAN_RUN_SCRIPT later.
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY nsresult
+  NotifyIME(const IMENotification& aIMENotification);
+
+  /**
+   * DispatchKeyboardEvent() maybe dispatches aKeyboardEvent.
+   *
+   * @param aMessage        Must be eKeyDown or eKeyUp.
+   *                        Use MaybeDispatchKeypressEvents() for dispatching
+   *                        eKeyPress.
+   * @param aKeyboardEvent  A keyboard event.
+   * @param aStatus         If dispatching event should be marked as consumed,
+   *                        set nsEventStatus_eConsumeNoDefault.  Otherwise,
+   *                        set nsEventStatus_eIgnore.  After dispatching
+   *                        a event and it's consumed this returns
+   *                        nsEventStatus_eConsumeNoDefault.
+   * @param aData           Calling this method may cause calling
+   *                        WillDispatchKeyboardEvent() of the listener.
+   *                        aData will be set to its argument.
+   * @return                true if an event is dispatched.  Otherwise, false.
+   */
+  bool DispatchKeyboardEvent(EventMessage aMessage,
+                             const WidgetKeyboardEvent& aKeyboardEvent,
+                             nsEventStatus& aStatus, void* aData = nullptr);
+
+  /**
+   * MaybeDispatchKeypressEvents() maybe dispatches a keypress event which is
+   * generated from aKeydownEvent.
+   *
+   * @param aKeyboardEvent  A keyboard event.
+   * @param aStatus         Sets the result when the caller dispatches
+   *                        aKeyboardEvent.  Note that if the value is
+   *                        nsEventStatus_eConsumeNoDefault, this does NOT
+   *                        dispatch keypress events.
+   *                        When this method dispatches one or more keypress
+   *                        events and one of them is consumed, this returns
+   *                        nsEventStatus_eConsumeNoDefault.
+   * @param aData           Calling this method may cause calling
+   *                        WillDispatchKeyboardEvent() of the listener.
+   *                        aData will be set to its argument.
+   * @param aNeedsCallback  Set true when caller needs to initialize each
+   *                        eKeyPress event immediately before dispatch.
+   *                        Then, WillDispatchKeyboardEvent() is always called.
+   * @return                true if one or more events are dispatched.
+   *                        Otherwise, false.
+   */
+  bool MaybeDispatchKeypressEvents(const WidgetKeyboardEvent& aKeyboardEvent,
+                                   nsEventStatus& aStatus,
+                                   void* aData = nullptr,
+                                   bool aNeedsCallback = false);
+
+ private:
+  // mWidget is owner of the instance.  When this is created, this is set.
+  // And when mWidget is released, this is cleared by OnDestroyWidget().
+  // Note that mWidget may be destroyed already (i.e., mWidget->Destroyed() may
+  // return true).
+  nsIWidget* mWidget;
+  // mListener is a weak reference to TextEventDispatcherListener.  That might
+  // be referred by JS.  Therefore, the listener might be difficult to release
+  // itself if this is a strong reference.  Additionally, it's difficult to
+  // check if a method to uninstall the listener is called by valid instance.
+  // So, using weak reference is the best way in this case.
+  nsWeakPtr mListener;
+  // mIMENotificationRequests should store current IME's notification requests.
+  // So, this may be invalid when IME doesn't have focus.
+  IMENotificationRequests mIMENotificationRequests;
+  // mWritingMode stores writing mode at current selection starting from
+  // receiving focus notification and until receiving blur notification.  When
+  // selection is changed, this is updated by every selection change
+  // notification.
+  Maybe<WritingMode> mWritingMode;
+
+  // mPendingComposition stores new composition string temporarily.
+  // These values will be used for dispatching eCompositionChange event
+  // in Flush().  When Flush() is called, the members will be cleared
+  // automatically.
+  class PendingComposition {
+   public:
+    PendingComposition();
+    nsresult SetString(const nsAString& aString);
+    nsresult AppendClause(uint32_t aLength, TextRangeType aTextRangeType);
+    nsresult SetCaret(uint32_t aOffset, uint32_t aLength);
+    nsresult Set(const nsAString& aString, const TextRangeArray* aRanges);
+    nsresult Flush(TextEventDispatcher* aDispatcher, nsEventStatus& aStatus,
+                   const WidgetEventTime* aEventTime);
+    const TextRangeArray* GetClauses() const { return mClauses; }
+    void Clear();
+
+   private:
+    nsString mString;
+    RefPtr<TextRangeArray> mClauses;
+    TextRange mCaret;
+    bool mReplacedNativeLineBreakers;
+
+    void EnsureClauseArray();
+
+    /**
+     * ReplaceNativeLineBreakers() replaces "\r\n" and "\r" to "\n" and adjust
+     * each clause information and the caret information.
+     */
+    void ReplaceNativeLineBreakers();
+
+    /**
+     * AdjustRange() adjusts aRange as in the string with XP line breakers.
+     *
+     * @param aRange            The reference to a range in aNativeString.
+     *                          This will be modified.
+     * @param aNativeString     The string with native line breakers.
+     *                          This may include "\r\n" and/or "\r".
+     */
+    static void AdjustRange(TextRange& aRange, const nsAString& aNativeString);
+  };
+  PendingComposition mPendingComposition;
+
+  // While dispatching an event, this is incremented.
+  uint16_t mDispatchingEvent;
+
+  enum InputTransactionType : uint8_t {
+    // No input transaction has been started.
+    eNoInputTransaction,
+    // Input transaction for native IME or keyboard event handler.  Note that
+    // keyboard events may be dispatched via parent process if there is.
+    // In remote processes, this is also used when events come from the parent
+    // process and are not for tests because we cannot distinguish if
+    // TextEventDispatcher has which type of transaction when it dispatches
+    // (eNativeInputTransaction or eSameProcessSyncInputTransaction).
+    eNativeInputTransaction,
+    // Input transaction for automated tests which are APZ-aware.  Note that
+    // keyboard events may be dispatched via parent process if there is.
+    eAsyncTestInputTransaction,
+    // Input transaction for automated tests which assume events are fired
+    // synchronously.  I.e., keyboard events are always dispatched in the
+    // current process.
+    // In remote processes, this is also used when events come from the parent
+    // process and are not dispatched by the instance itself for APZ-aware
+    // tests because this instance won't dispatch the events via the parent
+    // process again.
+    eSameProcessSyncTestInputTransaction,
+    // Input transaction for others (currently, only FuzzingFunctions).
+    // Events are fired synchronously in the process.
+    // XXX Should we make this async for testing default action handlers in
+    //     the main process?
+    eSameProcessSyncInputTransaction
+  };
+
+  InputTransactionType mInputTransactionType;
+
+  bool IsForTests() const {
+    return mInputTransactionType == eAsyncTestInputTransaction ||
+           mInputTransactionType == eSameProcessSyncTestInputTransaction;
+  }
+
+  // ShouldSendInputEventToAPZ() returns true when WidgetInputEvent should
+  // be dispatched via its parent process (if there is) for APZ.  Otherwise,
+  // when the input transaction is for IME of B2G or automated tests which
+  // isn't APZ-aware, WidgetInputEvent should be dispatched form current
+  // process directly.
+  bool ShouldSendInputEventToAPZ() const {
+    switch (mInputTransactionType) {
+      case eNativeInputTransaction:
+      case eAsyncTestInputTransaction:
+        return true;
+      case eSameProcessSyncTestInputTransaction:
+      case eSameProcessSyncInputTransaction:
+        return false;
+      case eNoInputTransaction:
+        NS_WARNING(
+            "Why does the caller need to dispatch an event when "
+            "there is no input transaction?");
+        return true;
+      default:
+        MOZ_CRASH("Define the behavior of new InputTransactionType");
+    }
+  }
+
+  // See IsComposing().
+  bool mIsComposing;
+
+  // See IsHandlingComposition().
+  bool mIsHandlingComposition;
+
+  // true while NOTIFY_IME_OF_FOCUS is received but NOTIFY_IME_OF_BLUR has not
+  // received yet.  Otherwise, false.
+  bool mHasFocus;
+
+  nsresult BeginInputTransactionInternal(TextEventDispatcherListener* aListener,
+                                         InputTransactionType aType);
+
+  /**
+   * InitEvent() initializes aEvent.  This must be called before dispatching
+   * the event.
+   */
+  void InitEvent(WidgetGUIEvent& aEvent) const;
+
+  /**
+   * DispatchEvent() dispatches aEvent on aWidget.
+   */
+  nsresult DispatchEvent(nsIWidget* aWidget, WidgetGUIEvent& aEvent,
+                         nsEventStatus& aStatus);
+
+  /**
+   * DispatchInputEvent() dispatches aEvent on aWidget.
+   */
+  nsresult DispatchInputEvent(nsIWidget* aWidget, WidgetInputEvent& aEvent,
+                              nsEventStatus& aStatus);
+
+  /**
+   * StartCompositionAutomaticallyIfNecessary() starts composition if it hasn't
+   * been started it yet.
+   *
+   * @param aStatus         If it succeeded to start composition normally, this
+   *                        returns nsEventStatus_eIgnore.  Otherwise, e.g.,
+   *                        the composition is canceled during dispatching
+   *                        compositionstart event, this returns
+   *                        nsEventStatus_eConsumeNoDefault.  In this case,
+   *                        the caller shouldn't keep doing its job.
+   * @param aEventTime      If this is not nullptr, WidgetCompositionEvent will
+   *                        be initialized with this.  Otherwise, initialized
+   *                        with the time at initializing.
+   * @return                Only when something unexpected occurs, this returns
+   *                        an error.  Otherwise, returns NS_OK even if aStatus
+   *                        is nsEventStatus_eConsumeNoDefault.
+   */
+  nsresult StartCompositionAutomaticallyIfNecessary(
+      nsEventStatus& aStatus, const WidgetEventTime* aEventTime);
+
+  /**
+   * DispatchKeyboardEventInternal() maybe dispatches aKeyboardEvent.
+   *
+   * @param aMessage        Must be eKeyDown, eKeyUp or eKeyPress.
+   * @param aKeyboardEvent  A keyboard event.  If aMessage is eKeyPress and
+   *                        the event is for second or later character, its
+   *                        mKeyValue should be empty string.
+   * @param aStatus         If dispatching event should be marked as consumed,
+   *                        set nsEventStatus_eConsumeNoDefault.  Otherwise,
+   *                        set nsEventStatus_eIgnore.  After dispatching
+   *                        a event and it's consumed this returns
+   *                        nsEventStatus_eConsumeNoDefault.
+   * @param aData           Calling this method may cause calling
+   *                        WillDispatchKeyboardEvent() of the listener.
+   *                        aData will be set to its argument.
+   * @param aIndexOfKeypress    This must be 0 if aMessage isn't eKeyPress or
+   *                            aKeyboard.mKeyNameIndex isn't
+   *                            KEY_NAME_INDEX_USE_STRING.  Otherwise, i.e.,
+   *                            when an eKeyPress event causes inputting
+   *                            text, this must be between 0 and
+   *                            mKeyValue.Length() - 1 since keypress events
+   *                            sending only one character per event.
+   * @param aNeedsCallback  Set true when caller needs to initialize each
+   *                        eKeyPress event immediately before dispatch.
+   *                        Then, WillDispatchKeyboardEvent() is always called.
+   * @return                true if an event is dispatched.  Otherwise, false.
+   */
+  // TODO: Mark this as MOZ_CAN_RUN_SCRIPT instead.
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY bool DispatchKeyboardEventInternal(
+      EventMessage aMessage, const WidgetKeyboardEvent& aKeyboardEvent,
+      nsEventStatus& aStatus, void* aData, uint32_t aIndexOfKeypress = 0,
+      bool aNeedsCallback = false);
+
+  /**
+   * ClearNotificationRequests() clears mIMENotificationRequests.
+   */
+  void ClearNotificationRequests();
+
+  /**
+   * UpdateNotificationRequests() updates mIMENotificationRequests with
+   * current state.  If the instance doesn't have focus, this clears
+   * mIMENotificationRequests.  Otherwise, updates it with both requests of
+   * current listener and native listener.
+   */
+  void UpdateNotificationRequests();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // #ifndef mozilla_widget_textcompositionsynthesizer_h_
diff --git a/widget/TextEventDispatcherListener.h b/widget/TextEventDispatcherListener.h
new file mode 100644
index 0000000000..cd846c6d38
--- /dev/null
+++ b/widget/TextEventDispatcherListener.h
@@ -0,0 +1,95 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_textinputdispatcherlistener_h_
+#define mozilla_textinputdispatcherlistener_h_
+
+#include "nsWeakReference.h"
+
+namespace mozilla {
+namespace widget {
+
+class TextEventDispatcher;
+struct IMENotification;
+struct IMENotificationRequests;
+
+#define NS_TEXT_INPUT_PROXY_LISTENER_IID \
+  {0xf2226f55,                           \
+   0x6ddb,                               \
+   0x40d5,                               \
+   {0x8a, 0x24, 0xce, 0x4d, 0x5b, 0x38, 0x15, 0xf0}};
+
+class TextEventDispatcherListener : public nsSupportsWeakReference {
+ public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_TEXT_INPUT_PROXY_LISTENER_IID)
+
+  /**
+   * NotifyIME() is called by TextEventDispatcher::NotifyIME().  This is a
+   * notification or request to IME.  See document of nsIWidget::NotifyIME()
+   * for the detail.
+   */
+  NS_IMETHOD NotifyIME(TextEventDispatcher* aTextEventDispatcher,
+                       const IMENotification& aNotification) = 0;
+
+  /**
+   * Returns preference for which IME notification are received by NotifyIME().
+   */
+  NS_IMETHOD_(IMENotificationRequests) GetIMENotificationRequests() = 0;
+
+  /**
+   * OnRemovedFrom() is called when the TextEventDispatcher stops working and
+   * is releasing the listener.
+   */
+  NS_IMETHOD_(void)
+  OnRemovedFrom(TextEventDispatcher* aTextEventDispatcher) = 0;
+
+  /**
+   * WillDispatchKeyboardEvent() may be called immediately before
+   * TextEventDispatcher dispatching a keyboard event.  This is called only
+   * during calling TextEventDispatcher::DispatchKeyboardEvent() or
+   * TextEventDispatcher::MaybeDispatchKeypressEvents().  But this may not
+   * be called if TextEventDispatcher thinks that the keyboard event doesn't
+   * need alternative char codes.
+   *
+   * This method can overwrite any members of aKeyboardEvent which is already
+   * initialized by TextEventDispatcher.  If it's necessary, this method should
+   * overwrite the charCode when Control key is pressed.  TextEventDispatcher
+   * computes charCode from mKeyValue.  However, when Control key is pressed,
+   * charCode should be an ASCII char.  In such case, this method needs to
+   * overwrite it properly.
+   *
+   * @param aTextEventDispatcher    Pointer to the caller.
+   * @param aKeyboardEvent          The event trying to dispatch.
+   *                                This is already initialized, but if it's
+   *                                necessary, this method should overwrite the
+   *                                members and set alternative char codes.
+   * @param aIndexOfKeypress        When aKeyboardEvent is eKeyPress event,
+   *                                it may be a sequence of keypress events
+   *                                if the key causes multiple characters.
+   *                                In such case, this indicates the index from
+   *                                first keypress event.
+   *                                If aKeyboardEvent is the first eKeyPress or
+   *                                other events, this value is 0.
+   * @param aData                   The pointer which was specified at calling
+   *                                the method of TextEventDispatcher.
+   *                                For example, if you do:
+   *                                |TextEventDispatcher->DispatchKeyboardEvent(
+   *                                   eKeyDown, event, status, this);|
+   *                                Then, aData of this method becomes |this|.
+   *                                Finally, you can use it like:
+   *                                |static_cast<NativeEventHandler*>(aData)|
+   */
+  NS_IMETHOD_(void)
+  WillDispatchKeyboardEvent(TextEventDispatcher* aTextEventDispatcher,
+                            WidgetKeyboardEvent& aKeyboardEvent,
+                            uint32_t aIndexOfKeypress, void* aData) = 0;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(TextEventDispatcherListener,
+                              NS_TEXT_INPUT_PROXY_LISTENER_IID)
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // #ifndef mozilla_textinputdispatcherlistener_h_
diff --git a/widget/TextEvents.h b/widget/TextEvents.h
new file mode 100644
index 0000000000..71d2e656e2
--- /dev/null
+++ b/widget/TextEvents.h
@@ -0,0 +1,1511 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_TextEvents_h__
+#define mozilla_TextEvents_h__
+
+#include <stdint.h>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/BasicEvents.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/EventForwards.h"  // for KeyNameIndex, temporarily
+#include "mozilla/FontRange.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/OwningNonNull.h"
+#include "mozilla/TextRange.h"
+#include "mozilla/WritingModes.h"
+#include "mozilla/dom/DataTransfer.h"
+#include "mozilla/dom/KeyboardEventBinding.h"
+#include "mozilla/dom/StaticRange.h"
+#include "mozilla/widget/IMEData.h"
+#include "mozilla/ipc/IPCForwards.h"
+#include "nsCOMPtr.h"
+#include "nsHashtablesFwd.h"
+#include "nsISelectionListener.h"
+#include "nsITransferable.h"
+#include "nsRect.h"
+#include "nsString.h"
+#include "nsTArray.h"
+
+class nsStringHashKey;
+
+/******************************************************************************
+ * virtual keycode values
+ ******************************************************************************/
+
+enum {
+#define NS_DEFINE_VK(aDOMKeyName, aDOMKeyCode) NS_##aDOMKeyName = aDOMKeyCode,
+#include "mozilla/VirtualKeyCodeList.h"
+#undef NS_DEFINE_VK
+  NS_VK_UNKNOWN = 0xFF
+};
+
+namespace mozilla {
+
+enum : uint32_t {
+  eKeyLocationStandard = dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_STANDARD,
+  eKeyLocationLeft = dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_LEFT,
+  eKeyLocationRight = dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_RIGHT,
+  eKeyLocationNumpad = dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_NUMPAD
+};
+
+const nsCString GetDOMKeyCodeName(uint32_t aKeyCode);
+
+namespace dom {
+class PBrowserParent;
+class PBrowserChild;
+}  // namespace dom
+namespace plugins {
+class PPluginInstanceChild;
+}  // namespace plugins
+
+enum class AccessKeyType {
+  // Handle access key for chrome.
+  eChrome,
+  // Handle access key for content.
+  eContent,
+  // Don't handle access key.
+  eNone
+};
+
+/******************************************************************************
+ * mozilla::AlternativeCharCode
+ *
+ * This stores alternative charCode values of a key event with some modifiers.
+ * The stored values proper for testing shortcut key or access key.
+ ******************************************************************************/
+
+struct AlternativeCharCode {
+  AlternativeCharCode() = default;
+  AlternativeCharCode(uint32_t aUnshiftedCharCode, uint32_t aShiftedCharCode)
+      : mUnshiftedCharCode(aUnshiftedCharCode),
+        mShiftedCharCode(aShiftedCharCode) {}
+
+  uint32_t mUnshiftedCharCode = 0u;
+  uint32_t mShiftedCharCode = 0u;
+
+  bool operator==(const AlternativeCharCode& aOther) const {
+    return mUnshiftedCharCode == aOther.mUnshiftedCharCode &&
+           mShiftedCharCode == aOther.mShiftedCharCode;
+  }
+  bool operator!=(const AlternativeCharCode& aOther) const {
+    return !(*this == aOther);
+  }
+};
+
+/******************************************************************************
+ * mozilla::ShortcutKeyCandidate
+ *
+ * This stores a candidate of shortcut key combination.
+ ******************************************************************************/
+
+struct ShortcutKeyCandidate {
+  enum class ShiftState : bool {
+    // Can ignore `Shift` modifier state when comparing the key combination.
+    // E.g., Ctrl + Shift + `:` in the US keyboard layout may match with
+    // Ctrl + `:` shortcut.
+    Ignorable,
+    // `Shift` modifier state should be respected.  I.e., Ctrl + `;` in the US
+    // keyboard layout never matches with Ctrl + Shift + `;` shortcut.
+    MatchExactly,
+  };
+
+  enum class SkipIfEarlierHandlerDisabled : bool {
+    // Even if an earlier handler is disabled, this may match with another
+    // handler for avoiding inaccessible shortcut with the active keyboard
+    // layout.
+    No,
+    // If an earlier handler (i.e., preferred handler) is disabled, this should
+    // not try to match.  E.g., Ctrl + `-` in the French keyboard layout when
+    // the zoom level is the minimum value, it should not match with Ctrl + `6`
+    // shortcut (French keyboard layout introduces `-` when pressing Digit6 key
+    // without Shift, and Shift + Digit6 introduces `6`).
+    Yes,
+  };
+
+  ShortcutKeyCandidate() = default;
+  ShortcutKeyCandidate(
+      uint32_t aCharCode, ShiftState aShiftState,
+      SkipIfEarlierHandlerDisabled aSkipIfEarlierHandlerDisabled)
+      : mCharCode(aCharCode),
+        mShiftState(aShiftState),
+        mSkipIfEarlierHandlerDisabled(aSkipIfEarlierHandlerDisabled) {}
+
+  // The mCharCode value which must match keyboard shortcut definition.
+  uint32_t mCharCode = 0;
+
+  ShiftState mShiftState = ShiftState::MatchExactly;
+  SkipIfEarlierHandlerDisabled mSkipIfEarlierHandlerDisabled =
+      SkipIfEarlierHandlerDisabled::No;
+};
+
+/******************************************************************************
+ * mozilla::IgnoreModifierState
+ *
+ * This stores flags for modifiers that should be ignored when matching
+ * XBL handlers.
+ ******************************************************************************/
+
+struct IgnoreModifierState {
+  // When mShift is true, Shift key state will be ignored.
+  bool mShift;
+  // When mMeta is true, Meta key state will be ignored.
+  bool mMeta;
+
+  IgnoreModifierState() : mShift(false), mMeta(false) {}
+};
+
+/******************************************************************************
+ * mozilla::WidgetKeyboardEvent
+ ******************************************************************************/
+
+class WidgetKeyboardEvent final : public WidgetInputEvent {
+ private:
+  friend class dom::PBrowserParent;
+  friend class dom::PBrowserChild;
+  friend struct IPC::ParamTraits<WidgetKeyboardEvent>;
+  ALLOW_DEPRECATED_READPARAM
+
+ protected:
+  WidgetKeyboardEvent()
+      : mNativeKeyEvent(nullptr),
+        mKeyCode(0),
+        mCharCode(0),
+        mPseudoCharCode(0),
+        mLocation(eKeyLocationStandard),
+        mUniqueId(0),
+        mKeyNameIndex(KEY_NAME_INDEX_Unidentified),
+        mCodeNameIndex(CODE_NAME_INDEX_UNKNOWN),
+        mIsRepeat(false),
+        mIsComposing(false),
+        mIsSynthesizedByTIP(false),
+        mMaybeSkippableInRemoteProcess(true),
+        mUseLegacyKeyCodeAndCharCodeValues(false),
+        mEditCommandsForSingleLineEditorInitialized(false),
+        mEditCommandsForMultiLineEditorInitialized(false),
+        mEditCommandsForRichTextEditorInitialized(false) {}
+
+ public:
+  WidgetKeyboardEvent* AsKeyboardEvent() override { return this; }
+
+  WidgetKeyboardEvent(bool aIsTrusted, EventMessage aMessage,
+                      nsIWidget* aWidget,
+                      EventClassID aEventClassID = eKeyboardEventClass,
+                      const WidgetEventTime* aTime = nullptr)
+      : WidgetInputEvent(aIsTrusted, aMessage, aWidget, aEventClassID, aTime),
+        mNativeKeyEvent(nullptr),
+        mKeyCode(0),
+        mCharCode(0),
+        mPseudoCharCode(0),
+        mLocation(eKeyLocationStandard),
+        mUniqueId(0),
+        mKeyNameIndex(KEY_NAME_INDEX_Unidentified),
+        mCodeNameIndex(CODE_NAME_INDEX_UNKNOWN),
+        mIsRepeat(false),
+        mIsComposing(false),
+        mIsSynthesizedByTIP(false),
+        mMaybeSkippableInRemoteProcess(true),
+        mUseLegacyKeyCodeAndCharCodeValues(false),
+        mEditCommandsForSingleLineEditorInitialized(false),
+        mEditCommandsForMultiLineEditorInitialized(false),
+        mEditCommandsForRichTextEditorInitialized(false) {}
+
+  // IsInputtingText() and IsInputtingLineBreak() are used to check if
+  // it should cause eKeyPress events even on web content.
+  // UI Events defines that "keypress" event should be fired "if and only if
+  // that key normally produces a character value".
+  // <https://www.w3.org/TR/uievents/#event-type-keypress>
+  // Additionally, for backward compatiblity with all existing browsers,
+  // there is a spec issue for Enter key press.
+  // <https://github.com/w3c/uievents/issues/183>
+  bool IsInputtingText() const {
+    // NOTE: On some keyboard layout, some characters are inputted with Control
+    //       key or Alt key, but at that time, widget clears the modifier flag
+    //       from eKeyPress event because our TextEditor won't handle eKeyPress
+    //       events as inputting text (bug 1346832).
+    // NOTE: There are some complicated issues of our traditional behavior.
+    //       -- On Windows, KeyboardLayout::WillDispatchKeyboardEvent() clears
+    //       MODIFIER_ALT and MODIFIER_CONTROL of eKeyPress event if it
+    //       should be treated as inputting a character because AltGr is
+    //       represented with both Alt key and Ctrl key are pressed, and
+    //       some keyboard layouts may produces a character with Ctrl key.
+    //       -- On Linux, KeymapWrapper doesn't have this hack since perhaps,
+    //       we don't have any bug reports that user cannot input proper
+    //       character with Alt and/or Ctrl key.
+    //       -- On macOS, IMEInputHandler::WillDispatchKeyboardEvent() clears
+    //       MODIFIER_ALT and MDOFIEIR_CONTROL of eKeyPress event only when
+    //       TextInputHandler::InsertText() has been called for the event.
+    //       I.e., they are cleared only when an editor has focus (even if IME
+    //       is disabled in password field or by |ime-mode: disabled;|) because
+    //       TextInputHandler::InsertText() is called while
+    //       TextInputHandler::HandleKeyDownEvent() calls interpretKeyEvents:
+    //       to notify text input processor of Cocoa (including IME).  In other
+    //       words, when we need to disable IME completey when no editor has
+    //       focus, we cannot call interpretKeyEvents:.  So,
+    //       TextInputHandler::InsertText() won't be called when no editor has
+    //       focus so that neither MODIFIER_ALT nor MODIFIER_CONTROL is
+    //       cleared.  So, fortunately, altKey and ctrlKey values of "keypress"
+    //       events are same as the other browsers only when no editor has
+    //       focus.
+    // NOTE: As mentioned above, for compatibility with the other browsers on
+    //       macOS, we should keep MODIFIER_ALT and MODIFIER_CONTROL flags of
+    //       eKeyPress events when no editor has focus.  However, Alt key,
+    //       labeled "option" on keyboard for Mac, is AltGraph key on the other
+    //       platforms.  So, even if MODIFIER_ALT is set, we need to dispatch
+    //       eKeyPress event even on web content unless mCharCode is 0.
+    //       Therefore, we need to ignore MODIFIER_ALT flag here only on macOS.
+    return mMessage == eKeyPress && mCharCode &&
+           !(mModifiers & (
+#ifndef XP_MACOSX
+                              // So, ignore MODIFIER_ALT only on macOS since
+                              // option key is used as AltGraph key on macOS.
+                              MODIFIER_ALT |
+#endif  // #ifndef XP_MAXOSX
+                              MODIFIER_CONTROL | MODIFIER_META));
+  }
+
+  bool IsInputtingLineBreak() const {
+    return mMessage == eKeyPress && mKeyNameIndex == KEY_NAME_INDEX_Enter &&
+           !(mModifiers & (MODIFIER_ALT | MODIFIER_CONTROL | MODIFIER_META));
+  }
+
+  /**
+   * ShouldKeyPressEventBeFiredOnContent() should be called only when the
+   * instance is eKeyPress event.  This returns true when the eKeyPress
+   * event should be fired even on content in the default event group.
+   */
+  bool ShouldKeyPressEventBeFiredOnContent() const {
+    MOZ_DIAGNOSTIC_ASSERT(mMessage == eKeyPress);
+    if (IsInputtingText() || IsInputtingLineBreak()) {
+      return true;
+    }
+    // Ctrl + Enter won't cause actual input in our editor.
+    // However, the other browsers fire keypress event in any platforms.
+    // So, for compatibility with them, we should fire keypress event for
+    // Ctrl + Enter too.
+    return mMessage == eKeyPress && mKeyNameIndex == KEY_NAME_INDEX_Enter &&
+           !(mModifiers & (MODIFIER_ALT | MODIFIER_META | MODIFIER_SHIFT));
+  }
+
+  WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eKeyboardEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetKeyboardEvent* result = new WidgetKeyboardEvent(
+        false, mMessage, nullptr, eKeyboardEventClass, this);
+    result->AssignKeyEventData(*this, true);
+    result->mEditCommandsForSingleLineEditor =
+        mEditCommandsForSingleLineEditor.Clone();
+    result->mEditCommandsForMultiLineEditor =
+        mEditCommandsForMultiLineEditor.Clone();
+    result->mEditCommandsForRichTextEditor =
+        mEditCommandsForRichTextEditor.Clone();
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  bool CanUserGestureActivateTarget() const {
+    // Printable keys, 'carriage return' and 'space' are supported user gestures
+    // for activating the document. However, if supported key is being pressed
+    // combining with other operation keys, such like alt, control ..etc., we
+    // won't activate the target for them because at that time user might
+    // interact with browser or window manager which doesn't necessarily
+    // demonstrate user's intent to play media.
+    const bool isCombiningWithOperationKeys = (IsControl() && !IsAltGraph()) ||
+                                              (IsAlt() && !IsAltGraph()) ||
+                                              IsMeta();
+    const bool isEnterOrSpaceKey =
+        mKeyNameIndex == KEY_NAME_INDEX_Enter || mKeyCode == NS_VK_SPACE;
+    return (PseudoCharCode() || isEnterOrSpaceKey) &&
+           (!isCombiningWithOperationKeys ||
+            // ctrl-c/ctrl-x/ctrl-v is quite common shortcut for clipboard
+            // operation.
+            // XXXedgar, we have to find a better way to handle browser keyboard
+            // shortcut for user activation, instead of just ignoring all
+            // combinations, see bug 1641171.
+            ((mKeyCode == dom::KeyboardEvent_Binding::DOM_VK_C ||
+              mKeyCode == dom::KeyboardEvent_Binding::DOM_VK_V ||
+              mKeyCode == dom::KeyboardEvent_Binding::DOM_VK_X) &&
+             IsAccel()));
+  }
+
+  // Returns true if this event is likely an user activation for a link or
+  // a link-like button, where modifier keys are likely be used for controlling
+  // where the link is opened.
+  //
+  // This returns false if the keyboard event is more likely an user-defined
+  // shortcut key.
+  bool CanReflectModifiersToUserActivation() const {
+    MOZ_ASSERT(CanUserGestureActivateTarget(),
+               "Consumer should check CanUserGestureActivateTarget first");
+    // 'carriage return' and 'space' are supported user gestures for activating
+    // a link or a button.
+    // A button often behaves like a link, by calling window.open inside its
+    // event handler.
+    //
+    // Access keys can also activate links/buttons, but access keys have their
+    // own modifiers, and those modifiers are not appropriate for reflecting to
+    // the user activation nor controlling where the link is opened.
+    return mKeyNameIndex == KEY_NAME_INDEX_Enter || mKeyCode == NS_VK_SPACE;
+  }
+
+  [[nodiscard]] bool ShouldWorkAsSpaceKey() const {
+    if (mKeyCode == NS_VK_SPACE) {
+      return true;
+    }
+    // Additionally, if the code value is "Space" and the key is not mapped to
+    // a function key (i.e., not a printable key), we should treat it as space
+    // key because the active keyboard layout may input different character
+    // from the ASCII white space (U+0020).  For example, NBSP (U+00A0).
+    return mKeyNameIndex == KEY_NAME_INDEX_USE_STRING &&
+           mCodeNameIndex == CODE_NAME_INDEX_Space;
+  }
+
+  /**
+   * CanTreatAsUserInput() returns true if the key is pressed for perhaps
+   * doing something on the web app or our UI.  This means that when this
+   * returns false, e.g., when user presses a modifier key, user is probably
+   * displeased by opening popup, entering fullscreen mode, etc.  Therefore,
+   * only when this returns true, such reactions should be allowed.
+   */
+  bool CanTreatAsUserInput() const {
+    if (!IsTrusted()) {
+      return false;
+    }
+    switch (mKeyNameIndex) {
+      case KEY_NAME_INDEX_Escape:
+      // modifier keys:
+      case KEY_NAME_INDEX_Alt:
+      case KEY_NAME_INDEX_AltGraph:
+      case KEY_NAME_INDEX_CapsLock:
+      case KEY_NAME_INDEX_Control:
+      case KEY_NAME_INDEX_Fn:
+      case KEY_NAME_INDEX_FnLock:
+      case KEY_NAME_INDEX_Meta:
+      case KEY_NAME_INDEX_NumLock:
+      case KEY_NAME_INDEX_ScrollLock:
+      case KEY_NAME_INDEX_Shift:
+      case KEY_NAME_INDEX_Symbol:
+      case KEY_NAME_INDEX_SymbolLock:
+      // legacy modifier keys:
+      case KEY_NAME_INDEX_Hyper:
+      case KEY_NAME_INDEX_Super:
+        return false;
+      default:
+        return true;
+    }
+  }
+
+  /**
+   * ShouldInteractionTimeRecorded() returns true if the handling time of
+   * the event should be recorded with the telemetry.
+   */
+  bool ShouldInteractionTimeRecorded() const {
+    // Let's record only when we can treat the instance is a user input.
+    return CanTreatAsUserInput();
+  }
+
+  // OS translated Unicode chars which are used for accesskey and accelkey
+  // handling. The handlers will try from first character to last character.
+  CopyableTArray<AlternativeCharCode> mAlternativeCharCodes;
+  // DOM KeyboardEvent.key only when mKeyNameIndex is KEY_NAME_INDEX_USE_STRING.
+  nsString mKeyValue;
+  // DOM KeyboardEvent.code only when mCodeNameIndex is
+  // CODE_NAME_INDEX_USE_STRING.
+  nsString mCodeValue;
+
+  // OS-specific native event can optionally be preserved.
+  // This is used to retrieve editing shortcut keys in the environment.
+  void* mNativeKeyEvent;
+  // A DOM keyCode value or 0.  If a keypress event whose mCharCode is 0, this
+  // should be 0.
+  uint32_t mKeyCode;
+  // If the instance is a keypress event of a printable key, this is a UTF-16
+  // value of the key.  Otherwise, 0.  This value must not be a control
+  // character when some modifiers are active.  Then, this value should be an
+  // unmodified value except Shift and AltGr.
+  uint32_t mCharCode;
+  // mPseudoCharCode is valid only when mMessage is an eKeyDown event.
+  // This stores mCharCode value of keypress event which is fired with same
+  // key value and same modifier state.
+  uint32_t mPseudoCharCode;
+  // One of eKeyLocation*
+  uint32_t mLocation;
+  // Unique id associated with a keydown / keypress event. It's ok if this wraps
+  // over long periods.
+  uint32_t mUniqueId;
+
+  // DOM KeyboardEvent.key
+  KeyNameIndex mKeyNameIndex;
+  // DOM KeyboardEvent.code
+  CodeNameIndex mCodeNameIndex;
+
+  // Indicates whether the event is generated by auto repeat or not.
+  // if this is keyup event, always false.
+  bool mIsRepeat;
+  // Indicates whether the event is generated during IME (or deadkey)
+  // composition.  This is initialized by EventStateManager.  So, key event
+  // dispatchers don't need to initialize this.
+  bool mIsComposing;
+  // Indicates whether the event is synthesized from Text Input Processor
+  // or an actual event from nsAppShell.
+  bool mIsSynthesizedByTIP;
+  // Indicates whether the event is skippable in remote process.
+  // Don't refer this member directly when you need to check this.
+  // Use CanSkipInRemoteProcess() instead.
+  bool mMaybeSkippableInRemoteProcess;
+  // Indicates whether the event should return legacy keyCode value and
+  // charCode value to web apps (one of them is always 0) or not, when it's
+  // an eKeyPress event.
+  bool mUseLegacyKeyCodeAndCharCodeValues;
+
+  bool CanSkipInRemoteProcess() const {
+    // If this is a repeat event (i.e., generated by auto-repeat feature of
+    // the platform), remove process may skip to handle it because of
+    // performances reasons..  However, if it's caused by odd keyboard utils,
+    // we should not ignore any key events even marked as repeated since
+    // generated key sequence may be important to input proper text.  E.g.,
+    // "SinhalaTamil IME" on Windows emulates dead key like input with
+    // generating WM_KEYDOWN for VK_PACKET (inputting any Unicode characters
+    // without keyboard layout information) and VK_BACK (Backspace) to remove
+    // previous character(s) and those messages may be marked as "repeat" by
+    // their bug.
+    return mIsRepeat && mMaybeSkippableInRemoteProcess;
+  }
+
+  /**
+   * If the key is an arrow key, and the current selection is in a vertical
+   * content, the caret should be moved to physically.  However, arrow keys
+   * are mapped to logical move commands in horizontal content.  Therefore,
+   * we need to check writing mode if and only if the key is an arrow key, and
+   * need to remap the command to logical command in vertical content if the
+   * writing mode at selection is vertical.  These methods help to convert
+   * arrow keys in horizontal content to correspnding direction arrow keys
+   * in vertical content.
+   */
+  bool NeedsToRemapNavigationKey() const {
+    // TODO: Use mKeyNameIndex instead.
+    return mKeyCode >= NS_VK_LEFT && mKeyCode <= NS_VK_DOWN;
+  }
+
+  uint32_t GetRemappedKeyCode(const WritingMode& aWritingMode) const {
+    if (!aWritingMode.IsVertical()) {
+      return mKeyCode;
+    }
+    switch (mKeyCode) {
+      case NS_VK_LEFT:
+        return aWritingMode.IsVerticalLR() ? NS_VK_UP : NS_VK_DOWN;
+      case NS_VK_RIGHT:
+        return aWritingMode.IsVerticalLR() ? NS_VK_DOWN : NS_VK_UP;
+      case NS_VK_UP:
+        return NS_VK_LEFT;
+      case NS_VK_DOWN:
+        return NS_VK_RIGHT;
+      default:
+        return mKeyCode;
+    }
+  }
+
+  KeyNameIndex GetRemappedKeyNameIndex(const WritingMode& aWritingMode) const {
+    if (!aWritingMode.IsVertical()) {
+      return mKeyNameIndex;
+    }
+    uint32_t remappedKeyCode = GetRemappedKeyCode(aWritingMode);
+    if (remappedKeyCode == mKeyCode) {
+      return mKeyNameIndex;
+    }
+    switch (remappedKeyCode) {
+      case NS_VK_LEFT:
+        return KEY_NAME_INDEX_ArrowLeft;
+      case NS_VK_RIGHT:
+        return KEY_NAME_INDEX_ArrowRight;
+      case NS_VK_UP:
+        return KEY_NAME_INDEX_ArrowUp;
+      case NS_VK_DOWN:
+        return KEY_NAME_INDEX_ArrowDown;
+      default:
+        MOZ_ASSERT_UNREACHABLE("Add a case for the new remapped key");
+        return mKeyNameIndex;
+    }
+  }
+
+  /**
+   * Retrieves all edit commands from mWidget.  This shouldn't be called when
+   * the instance is an untrusted event, doesn't have widget or in non-chrome
+   * process.
+   *
+   * @param aWritingMode
+   *                    When writing mode of focused element is vertical, this
+   *                    will resolve some key's physical direction to logical
+   *                    direction.  For doing it, this must be set to the
+   *                    writing mode at current selection.  However, when there
+   *                    is no focused element and no selection ranges, this
+   *                    should be set to Nothing().  Using the result of
+   *                    `TextEventDispatcher::MaybeQueryWritingModeAtSelection()`
+   *                    is recommended.
+   */
+  MOZ_CAN_RUN_SCRIPT void InitAllEditCommands(
+      const Maybe<WritingMode>& aWritingMode);
+
+  /**
+   * Retrieves edit commands from mWidget only for aType.  This shouldn't be
+   * called when the instance is an untrusted event or doesn't have widget.
+   *
+   * @param aWritingMode
+   *                    When writing mode of focused element is vertical, this
+   *                    will resolve some key's physical direction to logical
+   *                    direction.  For doing it, this must be set to the
+   *                    writing mode at current selection.  However, when there
+   *                    is no focused element and no selection ranges, this
+   *                    should be set to Nothing().  Using the result of
+   *                    `TextEventDispatcher::MaybeQueryWritingModeAtSelection()`
+   *                    is recommended.
+   * @return            false if some resource is not available to get
+   *                    commands unexpectedly.  Otherwise, true even if
+   *                    retrieved command is nothing.
+   */
+  MOZ_CAN_RUN_SCRIPT bool InitEditCommandsFor(
+      NativeKeyBindingsType aType, const Maybe<WritingMode>& aWritingMode);
+
+  /**
+   * PreventNativeKeyBindings() makes the instance to not cause any edit
+   * actions even if it matches with a native key binding.
+   */
+  void PreventNativeKeyBindings() {
+    mEditCommandsForSingleLineEditor.Clear();
+    mEditCommandsForMultiLineEditor.Clear();
+    mEditCommandsForRichTextEditor.Clear();
+    mEditCommandsForSingleLineEditorInitialized = true;
+    mEditCommandsForMultiLineEditorInitialized = true;
+    mEditCommandsForRichTextEditorInitialized = true;
+  }
+
+  /**
+   * EditCommandsConstRef() returns reference to edit commands for aType.
+   */
+  const nsTArray<CommandInt>& EditCommandsConstRef(
+      NativeKeyBindingsType aType) const {
+    return const_cast<WidgetKeyboardEvent*>(this)->EditCommandsRef(aType);
+  }
+
+  /**
+   * IsEditCommandsInitialized() returns true if edit commands for aType
+   * was already initialized.  Otherwise, false.
+   */
+  bool IsEditCommandsInitialized(NativeKeyBindingsType aType) const {
+    return const_cast<WidgetKeyboardEvent*>(this)->IsEditCommandsInitializedRef(
+        aType);
+  }
+
+  /**
+   * AreAllEditCommandsInitialized() returns true if edit commands for all
+   * types were already initialized.  Otherwise, false.
+   */
+  bool AreAllEditCommandsInitialized() const {
+    return mEditCommandsForSingleLineEditorInitialized &&
+           mEditCommandsForMultiLineEditorInitialized &&
+           mEditCommandsForRichTextEditorInitialized;
+  }
+
+  /**
+   * Execute edit commands for aType.
+   *
+   * @return        true if the caller should do nothing anymore.
+   *                false, otherwise.
+   */
+  typedef void (*DoCommandCallback)(Command, void*);
+  MOZ_CAN_RUN_SCRIPT bool ExecuteEditCommands(NativeKeyBindingsType aType,
+                                              DoCommandCallback aCallback,
+                                              void* aCallbackData);
+
+  // If the key should cause keypress events, this returns true.
+  // Otherwise, false.
+  bool ShouldCauseKeypressEvents() const;
+
+  // mCharCode value of non-eKeyPress events is always 0.  However, if
+  // non-eKeyPress event has one or more alternative char code values,
+  // its first item should be the mCharCode value of following eKeyPress event.
+  // PseudoCharCode() returns mCharCode value for eKeyPress event,
+  // the first alternative char code value of non-eKeyPress event or 0.
+  uint32_t PseudoCharCode() const {
+    return mMessage == eKeyPress ? mCharCode : mPseudoCharCode;
+  }
+  void SetCharCode(uint32_t aCharCode) {
+    if (mMessage == eKeyPress) {
+      mCharCode = aCharCode;
+    } else {
+      mPseudoCharCode = aCharCode;
+    }
+  }
+
+  void GetDOMKeyName(nsAString& aKeyName) {
+    if (mKeyNameIndex == KEY_NAME_INDEX_USE_STRING) {
+      aKeyName = mKeyValue;
+      return;
+    }
+    GetDOMKeyName(mKeyNameIndex, aKeyName);
+  }
+  void GetDOMCodeName(nsAString& aCodeName) {
+    if (mCodeNameIndex == CODE_NAME_INDEX_USE_STRING) {
+      aCodeName = mCodeValue;
+      return;
+    }
+    GetDOMCodeName(mCodeNameIndex, aCodeName);
+  }
+
+  /**
+   * GetFallbackKeyCodeOfPunctuationKey() returns a DOM keyCode value for
+   * aCodeNameIndex.  This is keyCode value of the key when active keyboard
+   * layout is ANSI (US), JIS or ABNT keyboard layout (the latter 2 layouts
+   * are used only when ANSI doesn't have the key).  The result is useful
+   * if the key doesn't produce ASCII character with active keyboard layout
+   * nor with alternative ASCII capable keyboard layout.
+   */
+  static uint32_t GetFallbackKeyCodeOfPunctuationKey(
+      CodeNameIndex aCodeNameIndex);
+
+  bool IsModifierKeyEvent() const {
+    return GetModifierForKeyName(mKeyNameIndex) != MODIFIER_NONE;
+  }
+
+  /**
+   * Get the candidates for shortcut key.
+   *
+   * @param aCandidates [out] the candidate shortcut key combination list.
+   *                          the first item is most preferred.
+   */
+  void GetShortcutKeyCandidates(ShortcutKeyCandidateArray& aCandidates) const;
+
+  /**
+   * Get the candidates for access key.
+   *
+   * @param aCandidates [out] the candidate access key list.
+   *                          the first item is most preferred.
+   */
+  void GetAccessKeyCandidates(nsTArray<uint32_t>& aCandidates) const;
+
+  /**
+   * Check whether the modifiers match with chrome access key or
+   * content access key.
+   */
+  bool ModifiersMatchWithAccessKey(AccessKeyType aType) const;
+
+  /**
+   * Return active modifiers which may match with access key.
+   * For example, even if Alt is access key modifier, then, when Control,
+   * CapseLock and NumLock are active, this returns only MODIFIER_CONTROL.
+   */
+  Modifiers ModifiersForAccessKeyMatching() const;
+
+  /**
+   * Return access key modifiers.
+   */
+  static Modifiers AccessKeyModifiers(AccessKeyType aType);
+
+  static void Shutdown();
+
+  /**
+   * ComputeLocationFromCodeValue() returns one of .mLocation value
+   * (eKeyLocation*) which is the most preferred value for the specified code
+   * value.
+   */
+  static uint32_t ComputeLocationFromCodeValue(CodeNameIndex aCodeNameIndex);
+
+  /**
+   * ComputeKeyCodeFromKeyNameIndex() return a .mKeyCode value which can be
+   * mapped from the specified key value.  Note that this returns 0 if the
+   * key name index is KEY_NAME_INDEX_Unidentified or KEY_NAME_INDEX_USE_STRING.
+   * This means that this method is useful only for non-printable keys.
+   */
+  static uint32_t ComputeKeyCodeFromKeyNameIndex(KeyNameIndex aKeyNameIndex);
+
+  /**
+   * ComputeCodeNameIndexFromKeyNameIndex() returns a code name index which
+   * is typically mapped to given key name index on the platform.
+   * Note that this returns CODE_NAME_INDEX_UNKNOWN if the key name index is
+   * KEY_NAME_INDEX_Unidentified or KEY_NAME_INDEX_USE_STRING.
+   * This means that this method is useful only for non-printable keys.
+   *
+   * @param aKeyNameIndex      A non-printable key name index.
+   * @param aLocation          Should be one of location value.  This is
+   *                           important when aKeyNameIndex may exist in
+   *                           both Numpad or Standard, or in both Left or
+   *                           Right.  If this is nothing, this method
+   *                           returns Left or Standard position's code
+   *                           value.
+   */
+  static CodeNameIndex ComputeCodeNameIndexFromKeyNameIndex(
+      KeyNameIndex aKeyNameIndex, const Maybe<uint32_t>& aLocation);
+
+  /**
+   * GetModifierForKeyName() returns a value of Modifier which is activated
+   * by the aKeyNameIndex.
+   */
+  static Modifier GetModifierForKeyName(KeyNameIndex aKeyNameIndex);
+
+  /**
+   * IsLeftOrRightModiferKeyNameIndex() returns true if aKeyNameIndex is a
+   * modifier key which may be in Left and Right location.
+   */
+  static bool IsLeftOrRightModiferKeyNameIndex(KeyNameIndex aKeyNameIndex) {
+    switch (aKeyNameIndex) {
+      case KEY_NAME_INDEX_Alt:
+      case KEY_NAME_INDEX_Control:
+      case KEY_NAME_INDEX_Meta:
+      case KEY_NAME_INDEX_Shift:
+        return true;
+      default:
+        return false;
+    }
+  }
+
+  /**
+   * IsLockableModifier() returns true if aKeyNameIndex is a lockable modifier
+   * key such as CapsLock and NumLock.
+   */
+  static bool IsLockableModifier(KeyNameIndex aKeyNameIndex);
+
+  static void GetDOMKeyName(KeyNameIndex aKeyNameIndex, nsAString& aKeyName);
+  static void GetDOMCodeName(CodeNameIndex aCodeNameIndex,
+                             nsAString& aCodeName);
+
+  static KeyNameIndex GetKeyNameIndex(const nsAString& aKeyValue);
+  static CodeNameIndex GetCodeNameIndex(const nsAString& aCodeValue);
+
+  static const char* GetCommandStr(Command aCommand);
+
+  void AssignKeyEventData(const WidgetKeyboardEvent& aEvent,
+                          bool aCopyTargets) {
+    AssignInputEventData(aEvent, aCopyTargets);
+
+    mKeyCode = aEvent.mKeyCode;
+    mCharCode = aEvent.mCharCode;
+    mPseudoCharCode = aEvent.mPseudoCharCode;
+    mLocation = aEvent.mLocation;
+    mAlternativeCharCodes = aEvent.mAlternativeCharCodes.Clone();
+    mIsRepeat = aEvent.mIsRepeat;
+    mIsComposing = aEvent.mIsComposing;
+    mKeyNameIndex = aEvent.mKeyNameIndex;
+    mCodeNameIndex = aEvent.mCodeNameIndex;
+    mKeyValue = aEvent.mKeyValue;
+    mCodeValue = aEvent.mCodeValue;
+    // Don't copy mNativeKeyEvent because it may be referred after its instance
+    // is destroyed.
+    mNativeKeyEvent = nullptr;
+    mUniqueId = aEvent.mUniqueId;
+    mIsSynthesizedByTIP = aEvent.mIsSynthesizedByTIP;
+    mMaybeSkippableInRemoteProcess = aEvent.mMaybeSkippableInRemoteProcess;
+    mUseLegacyKeyCodeAndCharCodeValues =
+        aEvent.mUseLegacyKeyCodeAndCharCodeValues;
+
+    // Don't copy mEditCommandsFor*Editor because it may require a lot of
+    // memory space.  For example, if the event is dispatched but grabbed by
+    // a JS variable, they are not necessary anymore.
+
+    mEditCommandsForSingleLineEditorInitialized =
+        aEvent.mEditCommandsForSingleLineEditorInitialized;
+    mEditCommandsForMultiLineEditorInitialized =
+        aEvent.mEditCommandsForMultiLineEditorInitialized;
+    mEditCommandsForRichTextEditorInitialized =
+        aEvent.mEditCommandsForRichTextEditorInitialized;
+  }
+
+  void AssignCommands(const WidgetKeyboardEvent& aEvent) {
+    mEditCommandsForSingleLineEditorInitialized =
+        aEvent.mEditCommandsForSingleLineEditorInitialized;
+    if (mEditCommandsForSingleLineEditorInitialized) {
+      mEditCommandsForSingleLineEditor =
+          aEvent.mEditCommandsForSingleLineEditor.Clone();
+    } else {
+      mEditCommandsForSingleLineEditor.Clear();
+    }
+    mEditCommandsForMultiLineEditorInitialized =
+        aEvent.mEditCommandsForMultiLineEditorInitialized;
+    if (mEditCommandsForMultiLineEditorInitialized) {
+      mEditCommandsForMultiLineEditor =
+          aEvent.mEditCommandsForMultiLineEditor.Clone();
+    } else {
+      mEditCommandsForMultiLineEditor.Clear();
+    }
+    mEditCommandsForRichTextEditorInitialized =
+        aEvent.mEditCommandsForRichTextEditorInitialized;
+    if (mEditCommandsForRichTextEditorInitialized) {
+      mEditCommandsForRichTextEditor =
+          aEvent.mEditCommandsForRichTextEditor.Clone();
+    } else {
+      mEditCommandsForRichTextEditor.Clear();
+    }
+  }
+
+ private:
+  static const char16_t* const kKeyNames[];
+  static const char16_t* const kCodeNames[];
+  typedef nsTHashMap<nsStringHashKey, KeyNameIndex> KeyNameIndexHashtable;
+  typedef nsTHashMap<nsStringHashKey, CodeNameIndex> CodeNameIndexHashtable;
+  static KeyNameIndexHashtable* sKeyNameIndexHashtable;
+  static CodeNameIndexHashtable* sCodeNameIndexHashtable;
+
+  // mEditCommandsFor*Editor store edit commands.  This should be initialized
+  // with InitEditCommandsFor().
+  // XXX Ideally, this should be array of Command rather than CommandInt.
+  //     However, ParamTraits isn't aware of enum array.
+  CopyableTArray<CommandInt> mEditCommandsForSingleLineEditor;
+  CopyableTArray<CommandInt> mEditCommandsForMultiLineEditor;
+  CopyableTArray<CommandInt> mEditCommandsForRichTextEditor;
+
+  nsTArray<CommandInt>& EditCommandsRef(NativeKeyBindingsType aType) {
+    switch (aType) {
+      case NativeKeyBindingsType::SingleLineEditor:
+        return mEditCommandsForSingleLineEditor;
+      case NativeKeyBindingsType::MultiLineEditor:
+        return mEditCommandsForMultiLineEditor;
+      case NativeKeyBindingsType::RichTextEditor:
+        return mEditCommandsForRichTextEditor;
+      default:
+        MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE(
+            "Invalid native key binding type");
+    }
+  }
+
+  // mEditCommandsFor*EditorInitialized are set to true when
+  // InitEditCommandsFor() initializes edit commands for the type.
+  bool mEditCommandsForSingleLineEditorInitialized;
+  bool mEditCommandsForMultiLineEditorInitialized;
+  bool mEditCommandsForRichTextEditorInitialized;
+
+  bool& IsEditCommandsInitializedRef(NativeKeyBindingsType aType) {
+    switch (aType) {
+      case NativeKeyBindingsType::SingleLineEditor:
+        return mEditCommandsForSingleLineEditorInitialized;
+      case NativeKeyBindingsType::MultiLineEditor:
+        return mEditCommandsForMultiLineEditorInitialized;
+      case NativeKeyBindingsType::RichTextEditor:
+        return mEditCommandsForRichTextEditorInitialized;
+      default:
+        MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE(
+            "Invalid native key binding type");
+    }
+  }
+};
+
+/******************************************************************************
+ * mozilla::WidgetCompositionEvent
+ ******************************************************************************/
+
+class WidgetCompositionEvent : public WidgetGUIEvent {
+ private:
+  friend class mozilla::dom::PBrowserParent;
+  friend class mozilla::dom::PBrowserChild;
+  ALLOW_DEPRECATED_READPARAM
+
+  WidgetCompositionEvent() : mOriginalMessage(eVoidEvent) {}
+
+ public:
+  virtual WidgetCompositionEvent* AsCompositionEvent() override { return this; }
+
+  WidgetCompositionEvent(bool aIsTrusted, EventMessage aMessage,
+                         nsIWidget* aWidget,
+                         const WidgetEventTime* aTime = nullptr)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eCompositionEventClass,
+                       aTime),
+        mNativeIMEContext(aWidget),
+        mOriginalMessage(eVoidEvent) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eCompositionEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetCompositionEvent* result =
+        new WidgetCompositionEvent(false, mMessage, nullptr, this);
+    result->AssignCompositionEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  // The composition string or the commit string.  If the instance is a
+  // compositionstart event, this is initialized with selected text by
+  // TextComposition automatically.
+  nsString mData;
+
+  RefPtr<TextRangeArray> mRanges;
+
+  // mNativeIMEContext stores the native IME context which causes the
+  // composition event.
+  widget::NativeIMEContext mNativeIMEContext;
+
+  // If the instance is a clone of another event, mOriginalMessage stores
+  // the another event's mMessage.
+  EventMessage mOriginalMessage;
+
+  // Composition ID considered by TextComposition.  If the event has not been
+  // handled by TextComposition yet, this is 0.  And also if the event is for
+  // a composition synthesized in a content process, this is always 0.
+  uint32_t mCompositionId = 0;
+
+  void AssignCompositionEventData(const WidgetCompositionEvent& aEvent,
+                                  bool aCopyTargets) {
+    AssignGUIEventData(aEvent, aCopyTargets);
+
+    mData = aEvent.mData;
+    mOriginalMessage = aEvent.mOriginalMessage;
+    mRanges = aEvent.mRanges;
+
+    // Currently, we don't need to copy the other members because they are
+    // for internal use only (not available from JS).
+  }
+
+  bool IsComposing() const { return mRanges && mRanges->IsComposing(); }
+
+  uint32_t TargetClauseOffset() const {
+    return mRanges ? mRanges->TargetClauseOffset() : 0;
+  }
+
+  uint32_t TargetClauseLength() const {
+    uint32_t length = UINT32_MAX;
+    if (mRanges) {
+      length = mRanges->TargetClauseLength();
+    }
+    return length == UINT32_MAX ? mData.Length() : length;
+  }
+
+  uint32_t RangeCount() const { return mRanges ? mRanges->Length() : 0; }
+
+  bool CausesDOMTextEvent() const {
+    return mMessage == eCompositionChange || mMessage == eCompositionCommit ||
+           mMessage == eCompositionCommitAsIs;
+  }
+
+  bool CausesDOMCompositionEndEvent() const {
+    return mMessage == eCompositionEnd || mMessage == eCompositionCommit ||
+           mMessage == eCompositionCommitAsIs;
+  }
+
+  bool IsFollowedByCompositionEnd() const {
+    return IsFollowedByCompositionEnd(mOriginalMessage);
+  }
+
+  static bool IsFollowedByCompositionEnd(EventMessage aEventMessage) {
+    return aEventMessage == eCompositionCommit ||
+           aEventMessage == eCompositionCommitAsIs;
+  }
+};
+
+/******************************************************************************
+ * mozilla::WidgetQueryContentEvent
+ ******************************************************************************/
+
+class WidgetQueryContentEvent : public WidgetGUIEvent {
+ private:
+  friend class dom::PBrowserParent;
+  friend class dom::PBrowserChild;
+  ALLOW_DEPRECATED_READPARAM
+
+  WidgetQueryContentEvent()
+      : mUseNativeLineBreak(true),
+        mWithFontRanges(false),
+        mNeedsToFlushLayout(true) {
+    MOZ_CRASH("WidgetQueryContentEvent is created without proper arguments");
+  }
+
+ public:
+  virtual WidgetQueryContentEvent* AsQueryContentEvent() override {
+    return this;
+  }
+
+  WidgetQueryContentEvent(bool aIsTrusted, EventMessage aMessage,
+                          nsIWidget* aWidget)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eQueryContentEventClass),
+        mUseNativeLineBreak(true),
+        mWithFontRanges(false),
+        mNeedsToFlushLayout(true) {}
+
+  WidgetQueryContentEvent(EventMessage aMessage,
+                          const WidgetQueryContentEvent& aOtherEvent)
+      : WidgetGUIEvent(aOtherEvent.IsTrusted(), aMessage,
+                       const_cast<nsIWidget*>(aOtherEvent.mWidget.get()),
+                       eQueryContentEventClass),
+        mUseNativeLineBreak(aOtherEvent.mUseNativeLineBreak),
+        mWithFontRanges(false),
+        mNeedsToFlushLayout(aOtherEvent.mNeedsToFlushLayout) {}
+
+  WidgetEvent* Duplicate() const override {
+    // This event isn't an internal event of any DOM event.
+    NS_ASSERTION(!IsAllowedToDispatchDOMEvent(),
+                 "WidgetQueryContentEvent needs to support Duplicate()");
+    MOZ_CRASH("WidgetQueryContentEvent doesn't support Duplicate()");
+  }
+
+  struct Options final {
+    bool mUseNativeLineBreak;
+    bool mRelativeToInsertionPoint;
+
+    explicit Options()
+        : mUseNativeLineBreak(true), mRelativeToInsertionPoint(false) {}
+
+    explicit Options(const WidgetQueryContentEvent& aEvent)
+        : mUseNativeLineBreak(aEvent.mUseNativeLineBreak),
+          mRelativeToInsertionPoint(aEvent.mInput.mRelativeToInsertionPoint) {}
+  };
+
+  void Init(const Options& aOptions) {
+    mUseNativeLineBreak = aOptions.mUseNativeLineBreak;
+    mInput.mRelativeToInsertionPoint = aOptions.mRelativeToInsertionPoint;
+    MOZ_ASSERT(mInput.IsValidEventMessage(mMessage));
+  }
+
+  void InitForQueryTextContent(int64_t aOffset, uint32_t aLength,
+                               const Options& aOptions = Options()) {
+    NS_ASSERTION(mMessage == eQueryTextContent, "wrong initializer is called");
+    mInput.mOffset = aOffset;
+    mInput.mLength = aLength;
+    Init(aOptions);
+    MOZ_ASSERT(mInput.IsValidOffset());
+  }
+
+  void InitForQueryCaretRect(int64_t aOffset,
+                             const Options& aOptions = Options()) {
+    NS_ASSERTION(mMessage == eQueryCaretRect, "wrong initializer is called");
+    mInput.mOffset = aOffset;
+    Init(aOptions);
+    MOZ_ASSERT(mInput.IsValidOffset());
+  }
+
+  void InitForQueryTextRect(int64_t aOffset, uint32_t aLength,
+                            const Options& aOptions = Options()) {
+    NS_ASSERTION(mMessage == eQueryTextRect, "wrong initializer is called");
+    mInput.mOffset = aOffset;
+    mInput.mLength = aLength;
+    Init(aOptions);
+    MOZ_ASSERT(mInput.IsValidOffset());
+  }
+
+  void InitForQuerySelectedText(SelectionType aSelectionType,
+                                const Options& aOptions = Options()) {
+    MOZ_ASSERT(mMessage == eQuerySelectedText);
+    MOZ_ASSERT(aSelectionType != SelectionType::eNone);
+    mInput.mSelectionType = aSelectionType;
+    Init(aOptions);
+  }
+
+  void InitForQueryDOMWidgetHittest(
+      const mozilla::LayoutDeviceIntPoint& aPoint) {
+    NS_ASSERTION(mMessage == eQueryDOMWidgetHittest,
+                 "wrong initializer is called");
+    mRefPoint = aPoint;
+  }
+
+  void InitForQueryTextRectArray(uint32_t aOffset, uint32_t aLength,
+                                 const Options& aOptions = Options()) {
+    NS_ASSERTION(mMessage == eQueryTextRectArray,
+                 "wrong initializer is called");
+    mInput.mOffset = aOffset;
+    mInput.mLength = aLength;
+    Init(aOptions);
+  }
+
+  void RequestFontRanges() {
+    MOZ_ASSERT(mMessage == eQueryTextContent);
+    mWithFontRanges = true;
+  }
+
+  bool Succeeded() const {
+    if (mReply.isNothing()) {
+      return false;
+    }
+    switch (mMessage) {
+      case eQueryTextContent:
+      case eQueryTextRect:
+      case eQueryCaretRect:
+        return mReply->mOffsetAndData.isSome();
+      default:
+        return true;
+    }
+  }
+
+  bool Failed() const { return !Succeeded(); }
+
+  bool FoundSelection() const {
+    MOZ_ASSERT(mMessage == eQuerySelectedText);
+    return Succeeded() && mReply->mOffsetAndData.isSome();
+  }
+
+  bool FoundChar() const {
+    MOZ_ASSERT(mMessage == eQueryCharacterAtPoint);
+    return Succeeded() && mReply->mOffsetAndData.isSome();
+  }
+
+  bool FoundTentativeCaretOffset() const {
+    MOZ_ASSERT(mMessage == eQueryCharacterAtPoint);
+    return Succeeded() && mReply->mTentativeCaretOffset.isSome();
+  }
+
+  bool DidNotFindSelection() const {
+    MOZ_ASSERT(mMessage == eQuerySelectedText);
+    return Failed() || mReply->mOffsetAndData.isNothing();
+  }
+
+  bool DidNotFindChar() const {
+    MOZ_ASSERT(mMessage == eQueryCharacterAtPoint);
+    return Failed() || mReply->mOffsetAndData.isNothing();
+  }
+
+  bool DidNotFindTentativeCaretOffset() const {
+    MOZ_ASSERT(mMessage == eQueryCharacterAtPoint);
+    return Failed() || mReply->mTentativeCaretOffset.isNothing();
+  }
+
+  bool mUseNativeLineBreak;
+  bool mWithFontRanges;
+  bool mNeedsToFlushLayout;
+  struct Input final {
+    uint32_t EndOffset() const {
+      CheckedInt<uint32_t> endOffset = CheckedInt<uint32_t>(mOffset) + mLength;
+      return NS_WARN_IF(!endOffset.isValid()) ? UINT32_MAX : endOffset.value();
+    }
+
+    int64_t mOffset;
+    uint32_t mLength;
+    SelectionType mSelectionType;
+    // If mOffset is true, mOffset is relative to the start offset of
+    // composition if there is, otherwise, the start of the first selection
+    // range.
+    bool mRelativeToInsertionPoint;
+
+    Input()
+        : mOffset(0),
+          mLength(0),
+          mSelectionType(SelectionType::eNormal),
+          mRelativeToInsertionPoint(false) {}
+
+    bool IsValidOffset() const {
+      return mRelativeToInsertionPoint || mOffset >= 0;
+    }
+    bool IsValidEventMessage(EventMessage aEventMessage) const {
+      if (!mRelativeToInsertionPoint) {
+        return true;
+      }
+      switch (aEventMessage) {
+        case eQueryTextContent:
+        case eQueryCaretRect:
+        case eQueryTextRect:
+          return true;
+        default:
+          return false;
+      }
+    }
+    bool MakeOffsetAbsolute(uint32_t aInsertionPointOffset) {
+      if (NS_WARN_IF(!mRelativeToInsertionPoint)) {
+        return true;
+      }
+      mRelativeToInsertionPoint = false;
+      // If mOffset + aInsertionPointOffset becomes negative value,
+      // we should assume the absolute offset is 0.
+      if (mOffset < 0 && -mOffset > aInsertionPointOffset) {
+        mOffset = 0;
+        return true;
+      }
+      // Otherwise, we don't allow too large offset.
+      CheckedInt<uint32_t> absOffset(mOffset + aInsertionPointOffset);
+      if (NS_WARN_IF(!absOffset.isValid())) {
+        mOffset = UINT32_MAX;
+        return false;
+      }
+      mOffset = absOffset.value();
+      return true;
+    }
+  } mInput;
+
+  struct Reply final {
+    EventMessage const mEventMessage;
+    void* mContentsRoot = nullptr;
+    Maybe<OffsetAndData<uint32_t>> mOffsetAndData;
+    // mTentativeCaretOffset is used by only eQueryCharacterAtPoint.
+    // This is the offset where caret would be if user clicked at the mRefPoint.
+    Maybe<uint32_t> mTentativeCaretOffset;
+    // mRect is used by eQueryTextRect, eQueryCaretRect, eQueryCharacterAtPoint
+    // and eQueryEditorRect. The coordinates is system coordinates relative to
+    // the top level widget of mFocusedWidget.  E.g., if a <xul:panel> which
+    // is owned by a window has focused editor, the offset of mRect is relative
+    // to the owner window, not the <xul:panel>.
+    mozilla::LayoutDeviceIntRect mRect;
+    // The return widget has the caret. This is set at all query events.
+    nsIWidget* mFocusedWidget = nullptr;
+    // mozilla::WritingMode value at the end (focus) of the selection
+    mozilla::WritingMode mWritingMode;
+    // Used by eQuerySelectionAsTransferable
+    nsCOMPtr<nsITransferable> mTransferable;
+    // Used by eQueryTextContent with font ranges requested
+    CopyableAutoTArray<mozilla::FontRange, 1> mFontRanges;
+    // Used by eQueryTextRectArray
+    CopyableTArray<mozilla::LayoutDeviceIntRect> mRectArray;
+    // true if selection is reversed (end < start)
+    bool mReversed = false;
+    // true if DOM element under mouse belongs to widget
+    bool mWidgetIsHit = false;
+    // true if mContentRoot is focused editable content
+    bool mIsEditableContent = false;
+
+    Reply() = delete;
+    explicit Reply(EventMessage aEventMessage) : mEventMessage(aEventMessage) {}
+
+    // Don't allow to copy/move because of `mEventMessage`.
+    Reply(const Reply& aOther) = delete;
+    Reply(Reply&& aOther) = delete;
+    Reply& operator=(const Reply& aOther) = delete;
+    Reply& operator=(Reply&& aOther) = delete;
+
+    MOZ_NEVER_INLINE_DEBUG uint32_t StartOffset() const {
+      MOZ_ASSERT(mOffsetAndData.isSome());
+      return mOffsetAndData->StartOffset();
+    }
+    MOZ_NEVER_INLINE_DEBUG uint32_t EndOffset() const {
+      MOZ_ASSERT(mOffsetAndData.isSome());
+      return mOffsetAndData->EndOffset();
+    }
+    MOZ_NEVER_INLINE_DEBUG uint32_t DataLength() const {
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mOffsetAndData.isSome() ? mOffsetAndData->Length() : 0;
+    }
+    MOZ_NEVER_INLINE_DEBUG uint32_t AnchorOffset() const {
+      MOZ_ASSERT(mEventMessage == eQuerySelectedText);
+      MOZ_ASSERT(mOffsetAndData.isSome());
+      return StartOffset() + (mReversed ? DataLength() : 0);
+    }
+
+    MOZ_NEVER_INLINE_DEBUG uint32_t FocusOffset() const {
+      MOZ_ASSERT(mEventMessage == eQuerySelectedText);
+      MOZ_ASSERT(mOffsetAndData.isSome());
+      return StartOffset() + (mReversed ? 0 : DataLength());
+    }
+
+    const WritingMode& WritingModeRef() const {
+      MOZ_ASSERT(mEventMessage == eQuerySelectedText ||
+                 mEventMessage == eQueryCaretRect ||
+                 mEventMessage == eQueryTextRect);
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mWritingMode;
+    }
+
+    MOZ_NEVER_INLINE_DEBUG const nsString& DataRef() const {
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mOffsetAndData.isSome() ? mOffsetAndData->DataRef()
+                                     : EmptyString();
+    }
+    MOZ_NEVER_INLINE_DEBUG bool IsDataEmpty() const {
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mOffsetAndData.isSome() ? mOffsetAndData->IsDataEmpty() : true;
+    }
+    MOZ_NEVER_INLINE_DEBUG bool IsOffsetInRange(uint32_t aOffset) const {
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mOffsetAndData.isSome() ? mOffsetAndData->IsOffsetInRange(aOffset)
+                                     : false;
+    }
+    MOZ_NEVER_INLINE_DEBUG bool IsOffsetInRangeOrEndOffset(
+        uint32_t aOffset) const {
+      MOZ_ASSERT(mOffsetAndData.isSome() ||
+                 mEventMessage == eQuerySelectedText);
+      return mOffsetAndData.isSome()
+                 ? mOffsetAndData->IsOffsetInRangeOrEndOffset(aOffset)
+                 : false;
+    }
+    MOZ_NEVER_INLINE_DEBUG void TruncateData(uint32_t aLength = 0) {
+      MOZ_ASSERT(mOffsetAndData.isSome());
+      mOffsetAndData->TruncateData(aLength);
+    }
+
+    friend std::ostream& operator<<(std::ostream& aStream,
+                                    const Reply& aReply) {
+      aStream << "{ ";
+      if (aReply.mEventMessage == eQuerySelectedText ||
+          aReply.mEventMessage == eQueryTextContent ||
+          aReply.mEventMessage == eQueryTextRect ||
+          aReply.mEventMessage == eQueryCaretRect ||
+          aReply.mEventMessage == eQueryCharacterAtPoint) {
+        aStream << "mOffsetAndData=" << ToString(aReply.mOffsetAndData).c_str()
+                << ", ";
+        if (aReply.mEventMessage == eQueryCharacterAtPoint) {
+          aStream << "mTentativeCaretOffset="
+                  << ToString(aReply.mTentativeCaretOffset).c_str() << ", ";
+        }
+      }
+      if (aReply.mOffsetAndData.isSome() && aReply.mOffsetAndData->Length()) {
+        if (aReply.mEventMessage == eQuerySelectedText) {
+          aStream << ", mReversed=" << (aReply.mReversed ? "true" : "false");
+        }
+        if (aReply.mEventMessage == eQuerySelectionAsTransferable) {
+          aStream << ", mTransferable=0x" << aReply.mTransferable;
+        }
+      }
+      if (aReply.mEventMessage == eQuerySelectedText ||
+          aReply.mEventMessage == eQueryTextRect ||
+          aReply.mEventMessage == eQueryCaretRect) {
+        aStream << ", mWritingMode=" << ToString(aReply.mWritingMode).c_str();
+      }
+      aStream << ", mContentsRoot=0x" << aReply.mContentsRoot
+              << ", mIsEditableContent="
+              << (aReply.mIsEditableContent ? "true" : "false")
+              << ", mFocusedWidget=0x" << aReply.mFocusedWidget;
+      if (aReply.mEventMessage == eQueryTextContent) {
+        aStream << ", mFontRanges={ Length()=" << aReply.mFontRanges.Length()
+                << " }";
+      } else if (aReply.mEventMessage == eQueryTextRect ||
+                 aReply.mEventMessage == eQueryCaretRect ||
+                 aReply.mEventMessage == eQueryCharacterAtPoint) {
+        aStream << ", mRect=" << ToString(aReply.mRect).c_str();
+      } else if (aReply.mEventMessage == eQueryTextRectArray) {
+        aStream << ", mRectArray={ Length()=" << aReply.mRectArray.Length()
+                << " }";
+      } else if (aReply.mEventMessage == eQueryDOMWidgetHittest) {
+        aStream << ", mWidgetIsHit="
+                << (aReply.mWidgetIsHit ? "true" : "false");
+      }
+      return aStream << " }";
+    }
+  };
+
+  void EmplaceReply() { mReply.emplace(mMessage); }
+  Maybe<Reply> mReply;
+
+  // values of mComputedScrollAction
+  enum { SCROLL_ACTION_NONE, SCROLL_ACTION_LINE, SCROLL_ACTION_PAGE };
+};
+
+/******************************************************************************
+ * mozilla::WidgetSelectionEvent
+ ******************************************************************************/
+
+class WidgetSelectionEvent : public WidgetGUIEvent {
+ private:
+  friend class mozilla::dom::PBrowserParent;
+  friend class mozilla::dom::PBrowserChild;
+  ALLOW_DEPRECATED_READPARAM
+
+  WidgetSelectionEvent()
+      : mOffset(0),
+        mLength(0),
+        mReversed(false),
+        mExpandToClusterBoundary(true),
+        mSucceeded(false),
+        mUseNativeLineBreak(true),
+        mReason(nsISelectionListener::NO_REASON) {}
+
+ public:
+  virtual WidgetSelectionEvent* AsSelectionEvent() override { return this; }
+
+  WidgetSelectionEvent(bool aIsTrusted, EventMessage aMessage,
+                       nsIWidget* aWidget)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eSelectionEventClass),
+        mOffset(0),
+        mLength(0),
+        mReversed(false),
+        mExpandToClusterBoundary(true),
+        mSucceeded(false),
+        mUseNativeLineBreak(true),
+        mReason(nsISelectionListener::NO_REASON) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    // This event isn't an internal event of any DOM event.
+    NS_ASSERTION(!IsAllowedToDispatchDOMEvent(),
+                 "WidgetSelectionEvent needs to support Duplicate()");
+    MOZ_CRASH("WidgetSelectionEvent doesn't support Duplicate()");
+    return nullptr;
+  }
+
+  // Start offset of selection
+  uint32_t mOffset;
+  // Length of selection
+  uint32_t mLength;
+  // Selection "anchor" should be in front
+  bool mReversed;
+  // Cluster-based or character-based
+  bool mExpandToClusterBoundary;
+  // true if setting selection succeeded.
+  bool mSucceeded;
+  // true if native line breaks are used for mOffset and mLength
+  bool mUseNativeLineBreak;
+  // Fennec provides eSetSelection reason codes for downstream
+  // use in AccessibleCaret visibility logic.
+  int16_t mReason;
+};
+
+/******************************************************************************
+ * mozilla::InternalEditorInputEvent
+ ******************************************************************************/
+
+class InternalEditorInputEvent : public InternalUIEvent {
+ private:
+  InternalEditorInputEvent()
+      : mData(VoidString()),
+        mInputType(EditorInputType::eUnknown),
+        mIsComposing(false) {}
+
+ public:
+  virtual InternalEditorInputEvent* AsEditorInputEvent() override {
+    return this;
+  }
+
+  InternalEditorInputEvent(bool aIsTrusted, EventMessage aMessage,
+                           nsIWidget* aWidget = nullptr,
+                           const WidgetEventTime* aTime = nullptr)
+      : InternalUIEvent(aIsTrusted, aMessage, aWidget, eEditorInputEventClass,
+                        aTime),
+        mData(VoidString()),
+        mInputType(EditorInputType::eUnknown) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eEditorInputEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    InternalEditorInputEvent* result =
+        new InternalEditorInputEvent(false, mMessage, nullptr, this);
+    result->AssignEditorInputEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  nsString mData;
+  RefPtr<dom::DataTransfer> mDataTransfer;
+  OwningNonNullStaticRangeArray mTargetRanges;
+
+  EditorInputType mInputType;
+
+  bool mIsComposing;
+
+  void AssignEditorInputEventData(const InternalEditorInputEvent& aEvent,
+                                  bool aCopyTargets) {
+    AssignUIEventData(aEvent, aCopyTargets);
+
+    mData = aEvent.mData;
+    mDataTransfer = aEvent.mDataTransfer;
+    mTargetRanges = aEvent.mTargetRanges.Clone();
+    mInputType = aEvent.mInputType;
+    mIsComposing = aEvent.mIsComposing;
+  }
+
+  void GetDOMInputTypeName(nsAString& aInputTypeName) {
+    GetDOMInputTypeName(mInputType, aInputTypeName);
+  }
+  static void GetDOMInputTypeName(EditorInputType aInputType,
+                                  nsAString& aInputTypeName);
+  static EditorInputType GetEditorInputType(const nsAString& aInputType);
+
+  static void Shutdown();
+
+ private:
+  static const char16_t* const kInputTypeNames[];
+  typedef nsTHashMap<nsStringHashKey, EditorInputType> InputTypeHashtable;
+  static InputTypeHashtable* sInputTypeHashtable;
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_TextEvents_h__
diff --git a/widget/TextRange.h b/widget/TextRange.h
new file mode 100644
index 0000000000..2ad41a6bc6
--- /dev/null
+++ b/widget/TextRange.h
@@ -0,0 +1,287 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_TextRage_h_
+#define mozilla_TextRage_h_
+
+#include <stdint.h>
+
+#include "mozilla/EventForwards.h"
+
+#include "nsColor.h"
+#include "nsISelectionController.h"
+#include "nsITextInputProcessor.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+
+/******************************************************************************
+ * mozilla::TextRangeStyle
+ ******************************************************************************/
+
+struct TextRangeStyle {
+  typedef uint8_t LineStyleType;
+  // FYI: Modify IME_RANGE_LINE_* too when you modify LineStyle.
+  enum class LineStyle : LineStyleType {
+    None,
+    Solid,
+    Dotted,
+    Dashed,
+    Double,
+    Wavy,
+  };
+  inline static LineStyle ToLineStyle(RawTextRangeType aRawLineStyle) {
+    switch (static_cast<LineStyle>(aRawLineStyle)) {
+      case LineStyle::None:
+      case LineStyle::Solid:
+      case LineStyle::Dotted:
+      case LineStyle::Dashed:
+      case LineStyle::Double:
+      case LineStyle::Wavy:
+        return static_cast<LineStyle>(aRawLineStyle);
+    }
+    MOZ_ASSERT_UNREACHABLE("aRawLineStyle value is invalid");
+    return LineStyle::None;
+  }
+
+  enum {
+    DEFINED_NONE = 0x00,
+    DEFINED_LINESTYLE = 0x01,
+    DEFINED_FOREGROUND_COLOR = 0x02,
+    DEFINED_BACKGROUND_COLOR = 0x04,
+    DEFINED_UNDERLINE_COLOR = 0x08
+  };
+
+  // Initialize all members, because TextRange instances may be compared by
+  // memcomp.
+  //
+  // FIXME(emilio): I don't think that'd be sound, as it has padding which the
+  // compiler is not guaranteed to initialize.
+  TextRangeStyle() { Clear(); }
+
+  void Clear() {
+    mDefinedStyles = DEFINED_NONE;
+    mLineStyle = LineStyle::None;
+    mIsBoldLine = false;
+    mForegroundColor = mBackgroundColor = mUnderlineColor = NS_RGBA(0, 0, 0, 0);
+  }
+
+  bool IsDefined() const { return mDefinedStyles != DEFINED_NONE; }
+
+  bool IsLineStyleDefined() const {
+    return (mDefinedStyles & DEFINED_LINESTYLE) != 0;
+  }
+
+  bool IsForegroundColorDefined() const {
+    return (mDefinedStyles & DEFINED_FOREGROUND_COLOR) != 0;
+  }
+
+  bool IsBackgroundColorDefined() const {
+    return (mDefinedStyles & DEFINED_BACKGROUND_COLOR) != 0;
+  }
+
+  bool IsUnderlineColorDefined() const {
+    return (mDefinedStyles & DEFINED_UNDERLINE_COLOR) != 0;
+  }
+
+  bool IsNoChangeStyle() const {
+    return !IsForegroundColorDefined() && !IsBackgroundColorDefined() &&
+           IsLineStyleDefined() && mLineStyle == LineStyle::None;
+  }
+
+  bool Equals(const TextRangeStyle& aOther) const {
+    if (mDefinedStyles != aOther.mDefinedStyles) return false;
+    if (IsLineStyleDefined() && (mLineStyle != aOther.mLineStyle ||
+                                 !mIsBoldLine != !aOther.mIsBoldLine))
+      return false;
+    if (IsForegroundColorDefined() &&
+        (mForegroundColor != aOther.mForegroundColor))
+      return false;
+    if (IsBackgroundColorDefined() &&
+        (mBackgroundColor != aOther.mBackgroundColor))
+      return false;
+    if (IsUnderlineColorDefined() &&
+        (mUnderlineColor != aOther.mUnderlineColor))
+      return false;
+    return true;
+  }
+
+  bool operator!=(const TextRangeStyle& aOther) const {
+    return !Equals(aOther);
+  }
+
+  bool operator==(const TextRangeStyle& aOther) const { return Equals(aOther); }
+
+  uint8_t mDefinedStyles;
+  LineStyle mLineStyle;  // DEFINED_LINESTYLE
+
+  bool mIsBoldLine;  // DEFINED_LINESTYLE
+
+  nscolor mForegroundColor;  // DEFINED_FOREGROUND_COLOR
+  nscolor mBackgroundColor;  // DEFINED_BACKGROUND_COLOR
+  nscolor mUnderlineColor;   // DEFINED_UNDERLINE_COLOR
+};
+
+/******************************************************************************
+ * mozilla::TextRange
+ ******************************************************************************/
+
+enum class TextRangeType : RawTextRangeType {
+  eUninitialized = 0x00,
+  eCaret = 0x01,
+  eRawClause = nsITextInputProcessor::ATTR_RAW_CLAUSE,
+  eSelectedRawClause = nsITextInputProcessor::ATTR_SELECTED_RAW_CLAUSE,
+  eConvertedClause = nsITextInputProcessor::ATTR_CONVERTED_CLAUSE,
+  eSelectedClause = nsITextInputProcessor::ATTR_SELECTED_CLAUSE
+};
+
+bool IsValidRawTextRangeValue(RawTextRangeType aRawTextRangeValue);
+RawTextRangeType ToRawTextRangeType(TextRangeType aTextRangeType);
+TextRangeType ToTextRangeType(RawTextRangeType aRawTextRangeType);
+const char* ToChar(TextRangeType aTextRangeType);
+SelectionType ToSelectionType(TextRangeType aTextRangeType);
+
+struct TextRange {
+  TextRange()
+      : mStartOffset(0),
+        mEndOffset(0),
+        mRangeType(TextRangeType::eUninitialized) {}
+
+  uint32_t mStartOffset;
+  // XXX Storing end offset makes the initializing code very complicated.
+  //     We should replace it with mLength.
+  uint32_t mEndOffset;
+
+  TextRangeStyle mRangeStyle;
+
+  TextRangeType mRangeType;
+
+  uint32_t Length() const { return mEndOffset - mStartOffset; }
+
+  bool IsClause() const { return mRangeType != TextRangeType::eCaret; }
+
+  bool Equals(const TextRange& aOther) const {
+    return mStartOffset == aOther.mStartOffset &&
+           mEndOffset == aOther.mEndOffset && mRangeType == aOther.mRangeType &&
+           mRangeStyle == aOther.mRangeStyle;
+  }
+
+  void RemoveCharacter(uint32_t aOffset) {
+    if (mStartOffset > aOffset) {
+      --mStartOffset;
+      --mEndOffset;
+    } else if (mEndOffset > aOffset) {
+      --mEndOffset;
+    }
+  }
+};
+
+/******************************************************************************
+ * mozilla::TextRangeArray
+ ******************************************************************************/
+class TextRangeArray final : public AutoTArray<TextRange, 10> {
+  friend class WidgetCompositionEvent;
+
+  ~TextRangeArray() = default;
+
+  NS_INLINE_DECL_REFCOUNTING(TextRangeArray)
+
+  const TextRange* GetTargetClause() const {
+    for (uint32_t i = 0; i < Length(); ++i) {
+      const TextRange& range = ElementAt(i);
+      if (range.mRangeType == TextRangeType::eSelectedRawClause ||
+          range.mRangeType == TextRangeType::eSelectedClause) {
+        return &range;
+      }
+    }
+    return nullptr;
+  }
+
+  // Returns target clause offset.  If there are selected clauses, this returns
+  // the first selected clause offset.  Otherwise, 0.
+  uint32_t TargetClauseOffset() const {
+    const TextRange* range = GetTargetClause();
+    return range ? range->mStartOffset : 0;
+  }
+
+  // Returns target clause length.  If there are selected clauses, this returns
+  // the first selected clause length.  Otherwise, UINT32_MAX.
+  uint32_t TargetClauseLength() const {
+    const TextRange* range = GetTargetClause();
+    return range ? range->Length() : UINT32_MAX;
+  }
+
+ public:
+  bool IsComposing() const {
+    for (uint32_t i = 0; i < Length(); ++i) {
+      if (ElementAt(i).IsClause()) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  bool Equals(const TextRangeArray& aOther) const {
+    size_t len = Length();
+    if (len != aOther.Length()) {
+      return false;
+    }
+    for (size_t i = 0; i < len; i++) {
+      if (!ElementAt(i).Equals(aOther.ElementAt(i))) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  void RemoveCharacter(uint32_t aOffset) {
+    for (size_t i = 0, len = Length(); i < len; i++) {
+      ElementAt(i).RemoveCharacter(aOffset);
+    }
+  }
+
+  bool HasCaret() const {
+    for (const TextRange& range : *this) {
+      if (range.mRangeType == TextRangeType::eCaret) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  bool HasClauses() const {
+    for (const TextRange& range : *this) {
+      if (range.IsClause()) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  uint32_t GetCaretPosition() const {
+    for (const TextRange& range : *this) {
+      if (range.mRangeType == TextRangeType::eCaret) {
+        return range.mStartOffset;
+      }
+    }
+    return UINT32_MAX;
+  }
+
+  const TextRange* GetFirstClause() const {
+    for (const TextRange& range : *this) {
+      // Look for the range of a clause whose start offset is 0 because the
+      // first clause's start offset is always 0.
+      if (range.IsClause() && !range.mStartOffset) {
+        return &range;
+      }
+    }
+    MOZ_ASSERT(!HasClauses());
+    return nullptr;
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_TextRage_h_
diff --git a/widget/TextRecognition.cpp b/widget/TextRecognition.cpp
new file mode 100644
index 0000000000..aa8ff98bb9
--- /dev/null
+++ b/widget/TextRecognition.cpp
@@ -0,0 +1,128 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TextRecognition.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/ShadowRoot.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/ContentChild.h"
+#include "nsTextNode.h"
+#include "imgIContainer.h"
+
+using namespace mozilla::dom;
+
+namespace mozilla::widget {
+
+auto TextRecognition::FindText(imgIContainer& aImage,
+                               const nsTArray<nsCString>& aLanguages)
+    -> RefPtr<NativePromise> {
+  // TODO: Maybe decode async.
+  RefPtr<gfx::SourceSurface> surface = aImage.GetFrame(
+      imgIContainer::FRAME_CURRENT,
+      imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
+  if (NS_WARN_IF(!surface)) {
+    return NativePromise::CreateAndReject("Failed to get surface"_ns, __func__);
+  }
+  RefPtr<gfx::DataSourceSurface> dataSurface = surface->GetDataSurface();
+  if (NS_WARN_IF(!dataSurface)) {
+    return NativePromise::CreateAndReject("Failed to get data surface"_ns,
+                                          __func__);
+  }
+  return FindText(*dataSurface, aLanguages);
+}
+
+auto TextRecognition::FindText(gfx::DataSourceSurface& aSurface,
+                               const nsTArray<nsCString>& aLanguages)
+    -> RefPtr<NativePromise> {
+  if (!IsSupported()) {
+    return NativePromise::CreateAndReject("Text recognition not available"_ns,
+                                          __func__);
+  }
+
+  if (XRE_IsContentProcess()) {
+    auto* contentChild = ContentChild::GetSingleton();
+    auto image = nsContentUtils::SurfaceToIPCImage(aSurface);
+    if (!image) {
+      return NativePromise::CreateAndReject("Failed to share data surface"_ns,
+                                            __func__);
+    }
+    auto promise = MakeRefPtr<NativePromise::Private>(__func__);
+    contentChild->SendFindImageText(std::move(*image), aLanguages)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [promise](TextRecognitionResultOrError&& aResultOrError) {
+              switch (aResultOrError.type()) {
+                case TextRecognitionResultOrError::Type::TTextRecognitionResult:
+                  promise->Resolve(
+                      std::move(aResultOrError.get_TextRecognitionResult()),
+                      __func__);
+                  break;
+                case TextRecognitionResultOrError::Type::TnsCString:
+                  promise->Reject(std::move(aResultOrError.get_nsCString()),
+                                  __func__);
+                  break;
+                default:
+                  MOZ_ASSERT_UNREACHABLE("Unknown result?");
+                  promise->Reject("Unknown error"_ns, __func__);
+                  break;
+              }
+            },
+            [promise](mozilla::ipc::ResponseRejectReason) {
+              promise->Reject("IPC rejection"_ns, __func__);
+            });
+    return promise;
+  }
+  return DoFindText(aSurface, aLanguages);
+}
+
+void TextRecognition::FillShadow(ShadowRoot& aShadow,
+                                 const TextRecognitionResult& aResult) {
+  auto& doc = *aShadow.OwnerDoc();
+  RefPtr<Element> div = doc.CreateHTMLElement(nsGkAtoms::div);
+  for (const auto& quad : aResult.quads()) {
+    RefPtr<Element> span = doc.CreateHTMLElement(nsGkAtoms::span);
+    // TODO: We probably want to position them here and so on. For now, expose
+    // the data as attributes so that it's easy to play with the returned values
+    // in JS.
+    {
+      nsAutoString points;
+      for (const auto& point : quad.points()) {
+        points.AppendFloat(point.x);
+        points.Append(u',');
+        points.AppendFloat(point.y);
+        points.Append(u',');
+      }
+      points.Trim(",");
+      span->SetAttribute(u"data-points"_ns, points, IgnoreErrors());
+      nsAutoString confidence;
+      confidence.AppendFloat(quad.confidence());
+      span->SetAttribute(u"data-confidence"_ns, confidence, IgnoreErrors());
+    }
+
+    {
+      RefPtr<nsTextNode> text = doc.CreateTextNode(quad.string());
+      span->AppendChildTo(text, true, IgnoreErrors());
+    }
+    div->AppendChildTo(span, true, IgnoreErrors());
+  }
+  aShadow.AppendChildTo(div, true, IgnoreErrors());
+}
+
+#ifndef XP_MACOSX
+auto TextRecognition::DoFindText(gfx::DataSourceSurface&,
+                                 const nsTArray<nsCString>&)
+    -> RefPtr<NativePromise> {
+  MOZ_CRASH("DoFindText is not implemented on this platform");
+}
+#endif
+
+bool TextRecognition::IsSupported() {
+#ifdef XP_MACOSX
+  return true;
+#else
+  return false;
+#endif
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/TextRecognition.h b/widget/TextRecognition.h
new file mode 100644
index 0000000000..246c860a88
--- /dev/null
+++ b/widget/TextRecognition.h
@@ -0,0 +1,54 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_nsTextRecognition__
+#define mozilla_widget_nsTextRecognition__
+
+#include "mozilla/MozPromise.h"
+#include "mozilla/gfx/Point.h"
+#include "nsTArray.h"
+
+class imgIContainer;
+namespace mozilla {
+
+namespace dom {
+class ShadowRoot;
+class TextRecognitionResultOrError;
+class TextRecognitionResult;
+}  // namespace dom
+
+namespace gfx {
+class SourceSurface;
+class DataSourceSurface;
+}  // namespace gfx
+
+namespace widget {
+
+class TextRecognition final {
+ public:
+  using NativePromise = MozPromise<dom::TextRecognitionResult, nsCString,
+                                   /* IsExclusive = */ true>;
+
+  TextRecognition() = default;
+
+  static void FillShadow(dom::ShadowRoot&, const dom::TextRecognitionResult&);
+
+  static RefPtr<NativePromise> FindText(imgIContainer&,
+                                        const nsTArray<nsCString>&);
+  static RefPtr<NativePromise> FindText(gfx::DataSourceSurface&,
+                                        const nsTArray<nsCString>&);
+  static bool IsSupported();
+
+ protected:
+  // This should be implemented in the OS specific file.
+  static RefPtr<NativePromise> DoFindText(gfx::DataSourceSurface&,
+                                          const nsTArray<nsCString>&);
+
+  ~TextRecognition() = default;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/Theme.cpp b/widget/Theme.cpp
new file mode 100644
index 0000000000..35c53240e5
--- /dev/null
+++ b/widget/Theme.cpp
@@ -0,0 +1,1718 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Theme.h"
+#include <utility>
+#include "ThemeCocoa.h"
+
+#include "ThemeDrawing.h"
+#include "Units.h"
+#include "mozilla/MathAlgorithms.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/HTMLMeterElement.h"
+#include "mozilla/dom/HTMLProgressElement.h"
+#include "mozilla/gfx/Rect.h"
+#include "mozilla/gfx/Types.h"
+#include "mozilla/gfx/Filters.h"
+#include "mozilla/RelativeLuminanceUtils.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/webrender/WebRenderAPI.h"
+#include "nsCSSColorUtils.h"
+#include "nsCSSRendering.h"
+#include "nsScrollbarFrame.h"
+#include "nsIScrollableFrame.h"
+#include "nsIScrollbarMediator.h"
+#include "nsDeviceContext.h"
+#include "nsLayoutUtils.h"
+#include "nsRangeFrame.h"
+#include "PathHelpers.h"
+#include "ScrollbarDrawingAndroid.h"
+#include "ScrollbarDrawingCocoa.h"
+#include "ScrollbarDrawingGTK.h"
+#include "ScrollbarDrawingWin.h"
+#include "ScrollbarDrawingWin11.h"
+
+#ifdef XP_WIN
+#  include "mozilla/WindowsVersion.h"
+#endif
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::gfx;
+using namespace mozilla::widget;
+
+namespace {
+
+static constexpr gfx::sRGBColor sColorGrey10(
+    gfx::sRGBColor::UnusualFromARGB(0xffe9e9ed));
+static constexpr gfx::sRGBColor sColorGrey10Alpha50(
+    gfx::sRGBColor::UnusualFromARGB(0x7fe9e9ed));
+static constexpr gfx::sRGBColor sColorGrey20(
+    gfx::sRGBColor::UnusualFromARGB(0xffd0d0d7));
+static constexpr gfx::sRGBColor sColorGrey30(
+    gfx::sRGBColor::UnusualFromARGB(0xffb1b1b9));
+static constexpr gfx::sRGBColor sColorGrey40(
+    gfx::sRGBColor::UnusualFromARGB(0xff8f8f9d));
+static constexpr gfx::sRGBColor sColorGrey40Alpha50(
+    gfx::sRGBColor::UnusualFromARGB(0x7f8f8f9d));
+static constexpr gfx::sRGBColor sColorGrey50(
+    gfx::sRGBColor::UnusualFromARGB(0xff676774));
+static constexpr gfx::sRGBColor sColorGrey60(
+    gfx::sRGBColor::UnusualFromARGB(0xff484851));
+
+static constexpr gfx::sRGBColor sColorMeterGreen10(
+    gfx::sRGBColor::UnusualFromARGB(0xff00ab60));
+static constexpr gfx::sRGBColor sColorMeterGreen20(
+    gfx::sRGBColor::UnusualFromARGB(0xff056139));
+static constexpr gfx::sRGBColor sColorMeterYellow10(
+    gfx::sRGBColor::UnusualFromARGB(0xffffbd4f));
+static constexpr gfx::sRGBColor sColorMeterYellow20(
+    gfx::sRGBColor::UnusualFromARGB(0xffd2811e));
+static constexpr gfx::sRGBColor sColorMeterRed10(
+    gfx::sRGBColor::UnusualFromARGB(0xffe22850));
+static constexpr gfx::sRGBColor sColorMeterRed20(
+    gfx::sRGBColor::UnusualFromARGB(0xff810220));
+
+static const CSSCoord kMinimumRangeThumbSize = 20.0f;
+static const CSSCoord kMinimumDropdownArrowButtonWidth = 18.0f;
+static const CSSCoord kMinimumSpinnerButtonWidth = 18.0f;
+static const CSSCoord kMinimumSpinnerButtonHeight = 9.0f;
+static const CSSCoord kButtonBorderWidth = 1.0f;
+static const CSSCoord kMenulistBorderWidth = 1.0f;
+static const CSSCoord kTextFieldBorderWidth = 1.0f;
+static const CSSCoord kRangeHeight = 6.0f;
+static const CSSCoord kProgressbarHeight = 6.0f;
+static const CSSCoord kMeterHeight = 12.0f;
+
+// nsCheckboxRadioFrame takes the bottom of the content box as the baseline.
+// This border-width makes its baseline 2px under the bottom, which is nice.
+static constexpr CSSCoord kCheckboxRadioBorderWidth = 2.0f;
+
+static constexpr sRGBColor sTransparent = sRGBColor::White(0.0);
+
+// This pushes and pops a clip rect to the draw target.
+//
+// This is done to reduce fuzz in places where we may have antialiasing,
+// because skia is not clip-invariant: given different clips, it does not
+// guarantee the same result, even if the painted content doesn't intersect
+// the clips.
+//
+// This is a bit sad, overall, but...
+struct MOZ_RAII AutoClipRect {
+  AutoClipRect(DrawTarget& aDt, const LayoutDeviceRect& aRect) : mDt(aDt) {
+    mDt.PushClipRect(aRect.ToUnknownRect());
+  }
+
+  ~AutoClipRect() { mDt.PopClip(); }
+
+ private:
+  DrawTarget& mDt;
+};
+
+static StaticRefPtr<Theme> gNativeInstance;
+static StaticRefPtr<Theme> gNonNativeInstance;
+static StaticRefPtr<Theme> gRDMInstance;
+
+}  // namespace
+
+#ifdef ANDROID
+already_AddRefed<Theme> do_CreateNativeThemeDoNotUseDirectly() {
+  // Android doesn't have a native theme.
+  return do_AddRef(new Theme(Theme::ScrollbarStyle()));
+}
+#endif
+
+already_AddRefed<nsITheme> do_GetBasicNativeThemeDoNotUseDirectly() {
+  if (MOZ_UNLIKELY(!gNonNativeInstance)) {
+    UniquePtr<ScrollbarDrawing> scrollbarDrawing = Theme::ScrollbarStyle();
+#ifdef MOZ_WIDGET_COCOA
+    gNonNativeInstance = new ThemeCocoa(std::move(scrollbarDrawing));
+#else
+    gNonNativeInstance = new Theme(std::move(scrollbarDrawing));
+#endif
+    ClearOnShutdown(&gNonNativeInstance);
+  }
+  return do_AddRef(gNonNativeInstance);
+}
+
+already_AddRefed<nsITheme> do_GetNativeThemeDoNotUseDirectly() {
+  if (MOZ_UNLIKELY(!gNativeInstance)) {
+    gNativeInstance = do_CreateNativeThemeDoNotUseDirectly();
+    ClearOnShutdown(&gNativeInstance);
+  }
+  return do_AddRef(gNativeInstance);
+}
+
+already_AddRefed<nsITheme> do_GetRDMThemeDoNotUseDirectly() {
+  if (MOZ_UNLIKELY(!gRDMInstance)) {
+    gRDMInstance = new Theme(MakeUnique<ScrollbarDrawingAndroid>());
+    ClearOnShutdown(&gRDMInstance);
+  }
+  return do_AddRef(gRDMInstance);
+}
+
+namespace mozilla::widget {
+
+NS_IMPL_ISUPPORTS_INHERITED(Theme, nsNativeTheme, nsITheme)
+
+static constexpr nsLiteralCString kPrefs[] = {
+    "widget.non-native-theme.use-theme-accent"_ns,
+    "widget.non-native-theme.win.scrollbar.use-system-size"_ns,
+    "widget.non-native-theme.scrollbar.size.override"_ns,
+    "widget.non-native-theme.scrollbar.style"_ns,
+};
+
+void Theme::Init() {
+  for (const auto& pref : kPrefs) {
+    Preferences::RegisterCallback(PrefChangedCallback, pref);
+  }
+  LookAndFeelChanged();
+}
+
+void Theme::Shutdown() {
+  for (const auto& pref : kPrefs) {
+    Preferences::UnregisterCallback(PrefChangedCallback, pref);
+  }
+}
+
+/* static */
+void Theme::LookAndFeelChanged() {
+  ThemeColors::RecomputeAccentColors();
+  if (gNonNativeInstance) {
+    gNonNativeInstance->SetScrollbarDrawing(ScrollbarStyle());
+  }
+  if (gNativeInstance) {
+    gNativeInstance->SetScrollbarDrawing(ScrollbarStyle());
+  }
+}
+
+auto Theme::GetDPIRatio(nsPresContext* aPc, StyleAppearance aAppearance)
+    -> DPIRatio {
+  // Widgets react to zoom, except scrollbars.
+  if (IsWidgetScrollbarPart(aAppearance)) {
+    return GetScrollbarDrawing().GetDPIRatioForScrollbarPart(aPc);
+  }
+  return DPIRatio(float(AppUnitsPerCSSPixel()) / aPc->AppUnitsPerDevPixel());
+}
+
+auto Theme::GetDPIRatio(nsIFrame* aFrame, StyleAppearance aAppearance)
+    -> DPIRatio {
+  return GetDPIRatio(aFrame->PresContext(), aAppearance);
+}
+
+// Checkbox and radio need to preserve aspect-ratio for compat. We also snap the
+// size to exact device pixels to avoid snapping disorting the circles.
+static LayoutDeviceRect CheckBoxRadioRect(const LayoutDeviceRect& aRect) {
+  // Place a square rect in the center of aRect.
+  auto size = std::trunc(std::min(aRect.width, aRect.height));
+  auto position = aRect.Center() - LayoutDevicePoint(size * 0.5, size * 0.5);
+  return LayoutDeviceRect(position, LayoutDeviceSize(size, size));
+}
+
+std::tuple<sRGBColor, sRGBColor, sRGBColor> Theme::ComputeCheckboxColors(
+    const ElementState& aState, StyleAppearance aAppearance,
+    const Colors& aColors) {
+  MOZ_ASSERT(aAppearance == StyleAppearance::Checkbox ||
+             aAppearance == StyleAppearance::Radio);
+
+  bool isDisabled = aState.HasState(ElementState::DISABLED);
+  bool isChecked = aState.HasState(ElementState::CHECKED);
+  bool isIndeterminate = aAppearance == StyleAppearance::Checkbox &&
+                         aState.HasState(ElementState::INDETERMINATE);
+
+  if (isChecked || isIndeterminate) {
+    if (isDisabled) {
+      auto bg = ComputeBorderColor(aState, aColors, OutlineCoversBorder::No);
+      auto fg = aColors.HighContrast()
+                    ? aColors.System(StyleSystemColor::Graytext)
+                    : sRGBColor::White(aColors.IsDark() ? .4f : .8f);
+      return std::make_tuple(bg, bg, fg);
+    }
+
+    if (aColors.HighContrast()) {
+      auto bg = aColors.System(StyleSystemColor::Selecteditem);
+      auto fg = aColors.System(StyleSystemColor::Selecteditemtext);
+      return std::make_tuple(bg, bg, fg);
+    }
+
+    bool isActive =
+        aState.HasAllStates(ElementState::HOVER | ElementState::ACTIVE);
+    bool isHovered = aState.HasState(ElementState::HOVER);
+    const auto& bg = isActive    ? aColors.Accent().GetDarker()
+                     : isHovered ? aColors.Accent().GetDark()
+                                 : aColors.Accent().Get();
+    const auto& fg = aColors.Accent().GetForeground();
+    return std::make_tuple(bg, bg, fg);
+  }
+
+  auto [bg, border] =
+      ComputeTextfieldColors(aState, aColors, OutlineCoversBorder::No);
+  // We don't paint a checkmark in this case so any color would do.
+  return std::make_tuple(bg, border, sTransparent);
+}
+
+sRGBColor Theme::ComputeBorderColor(const ElementState& aState,
+                                    const Colors& aColors,
+                                    OutlineCoversBorder aOutlineCoversBorder) {
+  bool isDisabled = aState.HasState(ElementState::DISABLED);
+  if (aColors.HighContrast()) {
+    return aColors.System(isDisabled ? StyleSystemColor::Graytext
+                                     : StyleSystemColor::Buttontext);
+  }
+  bool isActive =
+      aState.HasAllStates(ElementState::HOVER | ElementState::ACTIVE);
+  bool isHovered = aState.HasState(ElementState::HOVER);
+  bool isFocused = aState.HasState(ElementState::FOCUSRING);
+  if (isDisabled) {
+    return sColorGrey40Alpha50;
+  }
+  if (isFocused && aOutlineCoversBorder == OutlineCoversBorder::Yes) {
+    // If we draw the outline over the border, prevent issues where the border
+    // shows underneath if it snaps in the wrong direction by using a
+    // transparent border. An alternative to this is ensuring that we snap the
+    // offset in PaintRoundedFocusRect the same was a we snap border widths, so
+    // that negative offsets are guaranteed to cover the border.
+    // But this looks harder to mess up.
+    return sTransparent;
+  }
+  bool dark = aColors.IsDark();
+  if (isActive) {
+    return dark ? sColorGrey20 : sColorGrey60;
+  }
+  if (isHovered) {
+    return dark ? sColorGrey30 : sColorGrey50;
+  }
+  return sColorGrey40;
+}
+
+std::pair<sRGBColor, sRGBColor> Theme::ComputeButtonColors(
+    const ElementState& aState, const Colors& aColors, nsIFrame* aFrame) {
+  bool isActive =
+      aState.HasAllStates(ElementState::HOVER | ElementState::ACTIVE);
+  bool isDisabled = aState.HasState(ElementState::DISABLED);
+  bool isHovered = aState.HasState(ElementState::HOVER);
+
+  nscolor backgroundColor = [&] {
+    if (isDisabled) {
+      return aColors.SystemNs(StyleSystemColor::MozButtondisabledface);
+    }
+    if (isActive) {
+      return aColors.SystemNs(StyleSystemColor::MozButtonactiveface);
+    }
+    if (isHovered) {
+      return aColors.SystemNs(StyleSystemColor::MozButtonhoverface);
+    }
+    return aColors.SystemNs(StyleSystemColor::Buttonface);
+  }();
+
+  if (aState.HasState(ElementState::AUTOFILL)) {
+    backgroundColor = NS_ComposeColors(
+        backgroundColor,
+        aColors.SystemNs(StyleSystemColor::MozAutofillBackground));
+  }
+
+  const sRGBColor borderColor =
+      ComputeBorderColor(aState, aColors, OutlineCoversBorder::Yes);
+  return std::make_pair(sRGBColor::FromABGR(backgroundColor), borderColor);
+}
+
+std::pair<sRGBColor, sRGBColor> Theme::ComputeTextfieldColors(
+    const ElementState& aState, const Colors& aColors,
+    OutlineCoversBorder aOutlineCoversBorder) {
+  nscolor backgroundColor = [&] {
+    if (aState.HasState(ElementState::DISABLED)) {
+      return aColors.SystemNs(StyleSystemColor::MozDisabledfield);
+    }
+    return aColors.SystemNs(StyleSystemColor::Field);
+  }();
+
+  if (aState.HasState(ElementState::AUTOFILL)) {
+    backgroundColor = NS_ComposeColors(
+        backgroundColor,
+        aColors.SystemNs(StyleSystemColor::MozAutofillBackground));
+  }
+
+  const sRGBColor borderColor =
+      ComputeBorderColor(aState, aColors, aOutlineCoversBorder);
+  return std::make_pair(sRGBColor::FromABGR(backgroundColor), borderColor);
+}
+
+std::pair<sRGBColor, sRGBColor> Theme::ComputeRangeProgressColors(
+    const ElementState& aState, const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    return aColors.SystemPair(StyleSystemColor::Selecteditem,
+                              StyleSystemColor::Buttontext);
+  }
+
+  bool isActive =
+      aState.HasAllStates(ElementState::HOVER | ElementState::ACTIVE);
+  bool isDisabled = aState.HasState(ElementState::DISABLED);
+  bool isHovered = aState.HasState(ElementState::HOVER);
+
+  if (isDisabled) {
+    return std::make_pair(sColorGrey40Alpha50, sColorGrey40Alpha50);
+  }
+  if (isActive || isHovered) {
+    return std::make_pair(aColors.Accent().GetDark(),
+                          aColors.Accent().GetDarker());
+  }
+  return std::make_pair(aColors.Accent().Get(), aColors.Accent().GetDark());
+}
+
+std::pair<sRGBColor, sRGBColor> Theme::ComputeRangeTrackColors(
+    const ElementState& aState, const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    return aColors.SystemPair(StyleSystemColor::Window,
+                              StyleSystemColor::Buttontext);
+  }
+  bool isActive =
+      aState.HasAllStates(ElementState::HOVER | ElementState::ACTIVE);
+  bool isDisabled = aState.HasState(ElementState::DISABLED);
+  bool isHovered = aState.HasState(ElementState::HOVER);
+
+  if (isDisabled) {
+    return std::make_pair(sColorGrey10Alpha50, sColorGrey40Alpha50);
+  }
+  if (isActive || isHovered) {
+    return std::make_pair(sColorGrey20, sColorGrey50);
+  }
+  return std::make_pair(sColorGrey10, sColorGrey40);
+}
+
+std::pair<sRGBColor, sRGBColor> Theme::ComputeRangeThumbColors(
+    const ElementState& aState, const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    return aColors.SystemPair(StyleSystemColor::Selecteditemtext,
+                              StyleSystemColor::Selecteditem);
+  }
+
+  bool isActive =
+      aState.HasAllStates(ElementState::HOVER | ElementState::ACTIVE);
+  bool isDisabled = aState.HasState(ElementState::DISABLED);
+  bool isHovered = aState.HasState(ElementState::HOVER);
+
+  const sRGBColor& backgroundColor = [&] {
+    if (isDisabled) {
+      return sColorGrey40;
+    }
+    if (isActive) {
+      return aColors.Accent().Get();
+    }
+    if (isHovered) {
+      return sColorGrey60;
+    }
+    return sColorGrey50;
+  }();
+
+  const sRGBColor borderColor = sRGBColor::OpaqueWhite();
+  return std::make_pair(backgroundColor, borderColor);
+}
+
+std::pair<sRGBColor, sRGBColor> Theme::ComputeProgressColors(
+    const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    return aColors.SystemPair(StyleSystemColor::Selecteditem,
+                              StyleSystemColor::Buttontext);
+  }
+  return std::make_pair(aColors.Accent().Get(), aColors.Accent().GetDark());
+}
+
+std::pair<sRGBColor, sRGBColor> Theme::ComputeProgressTrackColors(
+    const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    return aColors.SystemPair(StyleSystemColor::Buttonface,
+                              StyleSystemColor::Buttontext);
+  }
+  return std::make_pair(sColorGrey10, sColorGrey40);
+}
+
+std::pair<sRGBColor, sRGBColor> Theme::ComputeMeterchunkColors(
+    const ElementState& aMeterState, const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    return ComputeProgressColors(aColors);
+  }
+  sRGBColor borderColor = sColorMeterGreen20;
+  sRGBColor chunkColor = sColorMeterGreen10;
+
+  if (aMeterState.HasState(ElementState::SUB_OPTIMUM)) {
+    borderColor = sColorMeterYellow20;
+    chunkColor = sColorMeterYellow10;
+  } else if (aMeterState.HasState(ElementState::SUB_SUB_OPTIMUM)) {
+    borderColor = sColorMeterRed20;
+    chunkColor = sColorMeterRed10;
+  }
+
+  return std::make_pair(chunkColor, borderColor);
+}
+
+std::array<sRGBColor, 3> Theme::ComputeFocusRectColors(const Colors& aColors) {
+  if (aColors.HighContrast()) {
+    return {aColors.System(StyleSystemColor::Selecteditem),
+            aColors.System(StyleSystemColor::Buttontext),
+            aColors.System(StyleSystemColor::Window)};
+  }
+  const auto& accent = aColors.Accent();
+  const sRGBColor middle =
+      aColors.IsDark() ? sRGBColor::Black(.3f) : sRGBColor::White(.3f);
+  return {accent.Get(), middle, accent.GetLight()};
+}
+
+template <typename PaintBackendData>
+void Theme::PaintRoundedFocusRect(PaintBackendData& aBackendData,
+                                  const LayoutDeviceRect& aRect,
+                                  const Colors& aColors, DPIRatio aDpiRatio,
+                                  CSSCoord aRadius, CSSCoord aOffset) {
+  // NOTE(emilio): If the widths or offsets here change, make sure to tweak
+  // the GetWidgetOverflow path for FocusOutline.
+  auto [innerColor, middleColor, outerColor] = ComputeFocusRectColors(aColors);
+
+  LayoutDeviceRect focusRect(aRect);
+
+  // The focus rect is painted outside of the border area (aRect), see:
+  //
+  //   data:text/html,<div style="border: 1px solid; outline: 2px solid
+  //   red">Foobar</div>
+  //
+  // But some controls might provide a negative offset to cover the border, if
+  // necessary.
+  CSSCoord strokeWidth = 2.0f;
+  auto strokeWidthDevPx =
+      LayoutDeviceCoord(ThemeDrawing::SnapBorderWidth(strokeWidth, aDpiRatio));
+  CSSCoord strokeRadius = aRadius;
+  focusRect.Inflate(aOffset * aDpiRatio + strokeWidthDevPx);
+
+  ThemeDrawing::PaintRoundedRectWithRadius(
+      aBackendData, focusRect, sTransparent, innerColor, strokeWidth,
+      strokeRadius, aDpiRatio);
+
+  strokeWidth = CSSCoord(1.0f);
+  strokeWidthDevPx =
+      LayoutDeviceCoord(ThemeDrawing::SnapBorderWidth(strokeWidth, aDpiRatio));
+  strokeRadius += strokeWidth;
+  focusRect.Inflate(strokeWidthDevPx);
+
+  ThemeDrawing::PaintRoundedRectWithRadius(
+      aBackendData, focusRect, sTransparent, middleColor, strokeWidth,
+      strokeRadius, aDpiRatio);
+
+  strokeWidth = CSSCoord(2.0f);
+  strokeWidthDevPx =
+      LayoutDeviceCoord(ThemeDrawing::SnapBorderWidth(strokeWidth, aDpiRatio));
+  strokeRadius += strokeWidth;
+  focusRect.Inflate(strokeWidthDevPx);
+
+  ThemeDrawing::PaintRoundedRectWithRadius(
+      aBackendData, focusRect, sTransparent, outerColor, strokeWidth,
+      strokeRadius, aDpiRatio);
+}
+
+void Theme::PaintCheckboxControl(DrawTarget& aDrawTarget,
+                                 const LayoutDeviceRect& aRect,
+                                 const ElementState& aState,
+                                 const Colors& aColors, DPIRatio aDpiRatio) {
+  auto [backgroundColor, borderColor, checkColor] =
+      ComputeCheckboxColors(aState, StyleAppearance::Checkbox, aColors);
+  {
+    const CSSCoord radius = 2.0f;
+    CSSCoord borderWidth = kCheckboxRadioBorderWidth;
+    if (backgroundColor == borderColor) {
+      borderWidth = 0.0f;
+    }
+    ThemeDrawing::PaintRoundedRectWithRadius(aDrawTarget, aRect,
+                                             backgroundColor, borderColor,
+                                             borderWidth, radius, aDpiRatio);
+  }
+
+  if (aState.HasState(ElementState::INDETERMINATE)) {
+    PaintIndeterminateMark(aDrawTarget, aRect, checkColor);
+  } else if (aState.HasState(ElementState::CHECKED)) {
+    PaintCheckMark(aDrawTarget, aRect, checkColor);
+  }
+
+  if (aState.HasState(ElementState::FOCUSRING)) {
+    PaintRoundedFocusRect(aDrawTarget, aRect, aColors, aDpiRatio, 5.0f, 1.0f);
+  }
+}
+
+constexpr CSSCoord kCheckboxRadioContentBoxSize = 10.0f;
+constexpr CSSCoord kCheckboxRadioBorderBoxSize =
+    kCheckboxRadioContentBoxSize + kCheckboxRadioBorderWidth * 2.0f;
+
+void Theme::PaintCheckMark(DrawTarget& aDrawTarget,
+                           const LayoutDeviceRect& aRect,
+                           const sRGBColor& aColor) {
+  // Points come from the coordinates on a 14X14 (kCheckboxRadioBorderBoxSize)
+  // unit box centered at 0,0
+  const float checkPolygonX[] = {-4.5f, -1.5f, -0.5f, 5.0f, 4.75f,
+                                 3.5f,  -0.5f, -1.5f, -3.5f};
+  const float checkPolygonY[] = {0.5f,  4.0f, 4.0f,  -2.5f, -4.0f,
+                                 -4.0f, 1.0f, 1.25f, -1.0f};
+  const int32_t checkNumPoints = sizeof(checkPolygonX) / sizeof(float);
+  const float scale =
+      ThemeDrawing::ScaleToFillRect(aRect, kCheckboxRadioBorderBoxSize);
+  auto center = aRect.Center().ToUnknownPoint();
+
+  RefPtr<PathBuilder> builder = aDrawTarget.CreatePathBuilder();
+  Point p = center + Point(checkPolygonX[0] * scale, checkPolygonY[0] * scale);
+  builder->MoveTo(p);
+  for (int32_t i = 1; i < checkNumPoints; i++) {
+    p = center + Point(checkPolygonX[i] * scale, checkPolygonY[i] * scale);
+    builder->LineTo(p);
+  }
+  RefPtr<Path> path = builder->Finish();
+
+  aDrawTarget.Fill(path, ColorPattern(ToDeviceColor(aColor)));
+}
+
+void Theme::PaintIndeterminateMark(DrawTarget& aDrawTarget,
+                                   const LayoutDeviceRect& aRect,
+                                   const sRGBColor& aColor) {
+  const CSSCoord borderWidth = 2.0f;
+  const float scale =
+      ThemeDrawing::ScaleToFillRect(aRect, kCheckboxRadioBorderBoxSize);
+
+  Rect rect = aRect.ToUnknownRect();
+  rect.y += (rect.height / 2) - (borderWidth * scale / 2);
+  rect.height = borderWidth * scale;
+  rect.x += (borderWidth * scale) + (borderWidth * scale / 8);
+  rect.width -= ((borderWidth * scale) + (borderWidth * scale / 8)) * 2;
+
+  aDrawTarget.FillRect(rect, ColorPattern(ToDeviceColor(aColor)));
+}
+
+template <typename PaintBackendData>
+void Theme::PaintStrokedCircle(PaintBackendData& aPaintData,
+                               const LayoutDeviceRect& aRect,
+                               const sRGBColor& aBackgroundColor,
+                               const sRGBColor& aBorderColor,
+                               const CSSCoord aBorderWidth,
+                               DPIRatio aDpiRatio) {
+  auto radius = LayoutDeviceCoord(aRect.Size().width) / aDpiRatio;
+  ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, aRect, aBackgroundColor,
+                                           aBorderColor, aBorderWidth, radius,
+                                           aDpiRatio);
+}
+
+void Theme::PaintCircleShadow(WebRenderBackendData& aWrData,
+                              const LayoutDeviceRect& aBoxRect,
+                              const LayoutDeviceRect& aClipRect,
+                              float aShadowAlpha, const CSSPoint& aShadowOffset,
+                              CSSCoord aShadowBlurStdDev, DPIRatio aDpiRatio) {
+  const bool kBackfaceIsVisible = true;
+  const LayoutDeviceCoord stdDev = aShadowBlurStdDev * aDpiRatio;
+  const LayoutDevicePoint shadowOffset = aShadowOffset * aDpiRatio;
+  const IntSize inflation =
+      gfxAlphaBoxBlur::CalculateBlurRadius(gfxPoint(stdDev, stdDev));
+  LayoutDeviceRect shadowRect = aBoxRect;
+  shadowRect.MoveBy(shadowOffset);
+  shadowRect.Inflate(inflation.width, inflation.height);
+  const auto boxRect = wr::ToLayoutRect(aBoxRect);
+  aWrData.mBuilder.PushBoxShadow(
+      wr::ToLayoutRect(shadowRect), wr::ToLayoutRect(aClipRect),
+      kBackfaceIsVisible, boxRect,
+      wr::ToLayoutVector2D(aShadowOffset * aDpiRatio),
+      wr::ToColorF(DeviceColor(0.0f, 0.0f, 0.0f, aShadowAlpha)), stdDev,
+      /* aSpread = */ 0.0f,
+      wr::ToBorderRadius(gfx::RectCornerRadii(aBoxRect.Size().width)),
+      wr::BoxShadowClipMode::Outset);
+}
+
+void Theme::PaintCircleShadow(DrawTarget& aDrawTarget,
+                              const LayoutDeviceRect& aBoxRect,
+                              const LayoutDeviceRect& aClipRect,
+                              float aShadowAlpha, const CSSPoint& aShadowOffset,
+                              CSSCoord aShadowBlurStdDev, DPIRatio aDpiRatio) {
+  Float stdDev = aShadowBlurStdDev * aDpiRatio;
+  Point offset = (aShadowOffset * aDpiRatio).ToUnknownPoint();
+
+  RefPtr<FilterNode> blurFilter =
+      aDrawTarget.CreateFilter(FilterType::GAUSSIAN_BLUR);
+  if (!blurFilter) {
+    return;
+  }
+
+  blurFilter->SetAttribute(ATT_GAUSSIAN_BLUR_STD_DEVIATION, stdDev);
+
+  IntSize inflation =
+      gfxAlphaBoxBlur::CalculateBlurRadius(gfxPoint(stdDev, stdDev));
+  Rect inflatedRect = aBoxRect.ToUnknownRect();
+  inflatedRect.Inflate(inflation.width, inflation.height);
+  Rect sourceRectInFilterSpace =
+      inflatedRect - aBoxRect.TopLeft().ToUnknownPoint();
+  Point destinationPointOfSourceRect = inflatedRect.TopLeft() + offset;
+
+  IntSize dtSize = RoundedToInt(aBoxRect.Size().ToUnknownSize());
+  RefPtr<DrawTarget> ellipseDT = aDrawTarget.CreateSimilarDrawTargetForFilter(
+      dtSize, SurfaceFormat::A8, blurFilter, blurFilter,
+      sourceRectInFilterSpace, destinationPointOfSourceRect);
+  if (!ellipseDT) {
+    return;
+  }
+
+  AutoClipRect clipRect(aDrawTarget, aClipRect);
+
+  RefPtr<Path> ellipse = MakePathForEllipse(
+      *ellipseDT, (aBoxRect - aBoxRect.TopLeft()).Center().ToUnknownPoint(),
+      aBoxRect.Size().ToUnknownSize());
+  ellipseDT->Fill(ellipse,
+                  ColorPattern(DeviceColor(0.0f, 0.0f, 0.0f, aShadowAlpha)));
+  RefPtr<SourceSurface> ellipseSurface = ellipseDT->Snapshot();
+
+  blurFilter->SetInput(IN_GAUSSIAN_BLUR_IN, ellipseSurface);
+  aDrawTarget.DrawFilter(blurFilter, sourceRectInFilterSpace,
+                         destinationPointOfSourceRect);
+}
+
+template <typename PaintBackendData>
+void Theme::PaintRadioControl(PaintBackendData& aPaintData,
+                              const LayoutDeviceRect& aRect,
+                              const ElementState& aState, const Colors& aColors,
+                              DPIRatio aDpiRatio) {
+  auto [backgroundColor, borderColor, checkColor] =
+      ComputeCheckboxColors(aState, StyleAppearance::Radio, aColors);
+  {
+    CSSCoord borderWidth = kCheckboxRadioBorderWidth;
+    if (backgroundColor == borderColor) {
+      borderWidth = 0.0f;
+    }
+    PaintStrokedCircle(aPaintData, aRect, backgroundColor, borderColor,
+                       borderWidth, aDpiRatio);
+  }
+
+  if (aState.HasState(ElementState::CHECKED)) {
+    LayoutDeviceRect rect(aRect);
+    auto width = LayoutDeviceCoord(
+        ThemeDrawing::SnapBorderWidth(kCheckboxRadioBorderWidth, aDpiRatio));
+    rect.Deflate(width);
+
+    PaintStrokedCircle(aPaintData, rect, backgroundColor, checkColor,
+                       kCheckboxRadioBorderWidth, aDpiRatio);
+  }
+
+  if (aState.HasState(ElementState::FOCUSRING)) {
+    PaintRoundedFocusRect(aPaintData, aRect, aColors, aDpiRatio, 5.0f, 1.0f);
+  }
+}
+
+template <typename PaintBackendData>
+void Theme::PaintTextField(PaintBackendData& aPaintData,
+                           const LayoutDeviceRect& aRect,
+                           const ElementState& aState, const Colors& aColors,
+                           DPIRatio aDpiRatio) {
+  auto [backgroundColor, borderColor] =
+      ComputeTextfieldColors(aState, aColors, OutlineCoversBorder::Yes);
+
+  const CSSCoord radius = 2.0f;
+
+  ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, aRect, backgroundColor,
+                                           borderColor, kTextFieldBorderWidth,
+                                           radius, aDpiRatio);
+
+  if (aState.HasState(ElementState::FOCUSRING)) {
+    PaintRoundedFocusRect(aPaintData, aRect, aColors, aDpiRatio,
+                          radius + kTextFieldBorderWidth,
+                          -kTextFieldBorderWidth);
+  }
+}
+
+template <typename PaintBackendData>
+void Theme::PaintListbox(PaintBackendData& aPaintData,
+                         const LayoutDeviceRect& aRect,
+                         const ElementState& aState, const Colors& aColors,
+                         DPIRatio aDpiRatio) {
+  const CSSCoord radius = 2.0f;
+  auto [backgroundColor, borderColor] =
+      ComputeTextfieldColors(aState, aColors, OutlineCoversBorder::Yes);
+
+  ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, aRect, backgroundColor,
+                                           borderColor, kMenulistBorderWidth,
+                                           radius, aDpiRatio);
+
+  if (aState.HasState(ElementState::FOCUSRING)) {
+    PaintRoundedFocusRect(aPaintData, aRect, aColors, aDpiRatio,
+                          radius + kMenulistBorderWidth, -kMenulistBorderWidth);
+  }
+}
+
+template <typename PaintBackendData>
+void Theme::PaintMenulist(PaintBackendData& aDrawTarget,
+                          const LayoutDeviceRect& aRect,
+                          const ElementState& aState, const Colors& aColors,
+                          DPIRatio aDpiRatio) {
+  const CSSCoord radius = 4.0f;
+  auto [backgroundColor, borderColor] = ComputeButtonColors(aState, aColors);
+
+  ThemeDrawing::PaintRoundedRectWithRadius(aDrawTarget, aRect, backgroundColor,
+                                           borderColor, kMenulistBorderWidth,
+                                           radius, aDpiRatio);
+
+  if (aState.HasState(ElementState::FOCUSRING)) {
+    PaintRoundedFocusRect(aDrawTarget, aRect, aColors, aDpiRatio,
+                          radius + kMenulistBorderWidth, -kMenulistBorderWidth);
+  }
+}
+
+enum class PhysicalArrowDirection {
+  Right,
+  Left,
+  Bottom,
+};
+
+void Theme::PaintMenulistArrow(nsIFrame* aFrame, DrawTarget& aDrawTarget,
+                               const LayoutDeviceRect& aRect) {
+  // not const: these may be negated in-place below
+  float polygonX[] = {-4.0f, -0.5f, 0.5f, 4.0f,  4.0f,
+                      3.0f,  0.0f,  0.0f, -3.0f, -4.0f};
+  float polygonY[] = {-1,    3.0f, 3.0f, -1.0f, -2.0f,
+                      -2.0f, 1.5f, 1.5f, -2.0f, -2.0f};
+
+  const float kPolygonSize = kMinimumDropdownArrowButtonWidth;
+  const auto direction = [&] {
+    const auto wm = aFrame->GetWritingMode();
+    switch (wm.GetBlockDir()) {
+      case WritingMode::BlockDir::eBlockLR:
+        return PhysicalArrowDirection::Right;
+      case WritingMode::BlockDir::eBlockRL:
+        return PhysicalArrowDirection::Left;
+      case WritingMode::BlockDir::eBlockTB:
+        return PhysicalArrowDirection::Bottom;
+    }
+    MOZ_ASSERT_UNREACHABLE("Unknown direction?");
+    return PhysicalArrowDirection::Bottom;
+  }();
+
+  auto const [xs, ys] = [&] {
+    using Pair = std::pair<const float*, const float*>;
+    switch (direction) {
+      case PhysicalArrowDirection::Left:
+        // rotate 90°: [[0,1],[-1,0]]
+        for (float& f : polygonY) {
+          f = -f;
+        }
+        return Pair(polygonY, polygonX);
+
+      case PhysicalArrowDirection::Right:
+        // rotate 270°: [[0,-1],[1,0]]
+        for (float& f : polygonX) {
+          f = -f;
+        }
+        return Pair(polygonY, polygonX);
+
+      case PhysicalArrowDirection::Bottom:
+        // rotate 0°: [[1,0],[0,1]]
+        return Pair(polygonX, polygonY);
+    }
+    MOZ_ASSERT_UNREACHABLE("Unknown direction?");
+    return Pair(polygonX, polygonY);
+  }();
+
+  const auto arrowColor = sRGBColor::FromABGR(
+      nsLayoutUtils::GetColor(aFrame, &nsStyleText::mWebkitTextFillColor));
+  ThemeDrawing::PaintArrow(aDrawTarget, aRect, xs, ys, kPolygonSize,
+                           ArrayLength(polygonX), arrowColor);
+}
+
+void Theme::PaintSpinnerButton(nsIFrame* aFrame, DrawTarget& aDrawTarget,
+                               const LayoutDeviceRect& aRect,
+                               const ElementState& aState,
+                               StyleAppearance aAppearance,
+                               const Colors& aColors, DPIRatio aDpiRatio) {
+  auto [backgroundColor, borderColor] = ComputeButtonColors(aState, aColors);
+
+  aDrawTarget.FillRect(aRect.ToUnknownRect(),
+                       ColorPattern(ToDeviceColor(backgroundColor)));
+
+  const float kPolygonX[] = {-3.5f, -0.5f, 0.5f, 3.5f,  3.5f,
+                             2.5f,  0.0f,  0.0f, -2.5f, -3.5f};
+  float polygonY[] = {-1.5f, 1.5f, 1.5f, -1.5f, -2.5f,
+                      -2.5f, 0.0f, 0.0f, -2.5f, -2.5f};
+
+  const float kPolygonSize = kMinimumSpinnerButtonHeight;
+  if (aAppearance == StyleAppearance::SpinnerUpbutton) {
+    for (auto& coord : polygonY) {
+      coord = -coord;
+    }
+  }
+
+  ThemeDrawing::PaintArrow(aDrawTarget, aRect, kPolygonX, polygonY,
+                           kPolygonSize, ArrayLength(kPolygonX), borderColor);
+}
+
+template <typename PaintBackendData>
+void Theme::PaintRange(nsIFrame* aFrame, PaintBackendData& aPaintData,
+                       const LayoutDeviceRect& aRect,
+                       const ElementState& aState, const Colors& aColors,
+                       DPIRatio aDpiRatio, bool aHorizontal) {
+  nsRangeFrame* rangeFrame = do_QueryFrame(aFrame);
+  if (!rangeFrame) {
+    return;
+  }
+
+  auto tickMarks = rangeFrame->TickMarks();
+  double progress = rangeFrame->GetValueAsFractionOfRange();
+  auto rect = aRect;
+  LayoutDeviceRect thumbRect(0, 0, kMinimumRangeThumbSize * aDpiRatio,
+                             kMinimumRangeThumbSize * aDpiRatio);
+  LayoutDeviceRect progressClipRect(aRect);
+  LayoutDeviceRect trackClipRect(aRect);
+  const LayoutDeviceCoord verticalSize = kRangeHeight * aDpiRatio;
+  const LayoutDeviceCoord tickMarkWidth(
+      ThemeDrawing::SnapBorderWidth(1.0f, aDpiRatio));
+  const LayoutDeviceCoord tickMarkHeight(
+      ThemeDrawing::SnapBorderWidth(5.0f, aDpiRatio));
+  LayoutDevicePoint tickMarkOrigin, tickMarkDirection;
+  LayoutDeviceSize tickMarkSize;
+  if (aHorizontal) {
+    rect.height = verticalSize;
+    rect.y = aRect.y + (aRect.height - rect.height) / 2;
+    tickMarkSize = LayoutDeviceSize(tickMarkWidth, tickMarkHeight);
+    thumbRect.y = aRect.y + (aRect.height - thumbRect.height) / 2;
+
+    if (IsFrameRTL(aFrame)) {
+      tickMarkOrigin =
+          LayoutDevicePoint(aRect.XMost() - thumbRect.width / 2, aRect.YMost());
+      tickMarkDirection = LayoutDevicePoint(-1.0f, 0.0f);
+      thumbRect.x =
+          aRect.x + (aRect.width - thumbRect.width) * (1.0 - progress);
+      float midPoint = thumbRect.Center().X();
+      trackClipRect.SetBoxX(aRect.X(), midPoint);
+      progressClipRect.SetBoxX(midPoint, aRect.XMost());
+    } else {
+      tickMarkOrigin =
+          LayoutDevicePoint(aRect.x + thumbRect.width / 2, aRect.YMost());
+      tickMarkDirection = LayoutDevicePoint(1.0, 0.0f);
+      thumbRect.x = aRect.x + (aRect.width - thumbRect.width) * progress;
+      float midPoint = thumbRect.Center().X();
+      progressClipRect.SetBoxX(aRect.X(), midPoint);
+      trackClipRect.SetBoxX(midPoint, aRect.XMost());
+    }
+  } else {
+    rect.width = verticalSize;
+    rect.x = aRect.x + (aRect.width - rect.width) / 2;
+    tickMarkOrigin = LayoutDevicePoint(aRect.XMost() - tickMarkHeight / 4,
+                                       aRect.YMost() - thumbRect.width / 2);
+    tickMarkDirection = LayoutDevicePoint(0.0f, -1.0f);
+    tickMarkSize = LayoutDeviceSize(tickMarkHeight, tickMarkWidth);
+    thumbRect.x = aRect.x + (aRect.width - thumbRect.width) / 2;
+
+    if (rangeFrame->IsUpwards()) {
+      thumbRect.y =
+          aRect.y + (aRect.height - thumbRect.height) * (1.0 - progress);
+      float midPoint = thumbRect.Center().Y();
+      trackClipRect.SetBoxY(aRect.Y(), midPoint);
+      progressClipRect.SetBoxY(midPoint, aRect.YMost());
+    } else {
+      thumbRect.y = aRect.y + (aRect.height - thumbRect.height) * progress;
+      float midPoint = thumbRect.Center().Y();
+      trackClipRect.SetBoxY(midPoint, aRect.YMost());
+      progressClipRect.SetBoxY(aRect.Y(), midPoint);
+    }
+  }
+
+  const CSSCoord borderWidth = 1.0f;
+  const CSSCoord radius = 3.0f;
+
+  auto [progressColor, progressBorderColor] =
+      ComputeRangeProgressColors(aState, aColors);
+  auto [trackColor, trackBorderColor] =
+      ComputeRangeTrackColors(aState, aColors);
+  auto tickMarkColor = trackBorderColor;
+
+  ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, rect, progressClipRect,
+                                           progressColor, progressBorderColor,
+                                           borderWidth, radius, aDpiRatio);
+
+  ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, rect, trackClipRect,
+                                           trackColor, trackBorderColor,
+                                           borderWidth, radius, aDpiRatio);
+
+  if (!aState.HasState(ElementState::DISABLED)) {
+    // Ensure the shadow doesn't expand outside of our overflow rect declared in
+    // GetWidgetOverflow().
+    auto overflowRect = aRect;
+    overflowRect.Inflate(CSSCoord(6.0f) * aDpiRatio);
+    // Thumb shadow
+    PaintCircleShadow(aPaintData, thumbRect, overflowRect, 0.3f,
+                      CSSPoint(0.0f, 2.0f), 2.0f, aDpiRatio);
+  }
+
+  tickMarkDirection.x *= aRect.width - thumbRect.width;
+  tickMarkDirection.y *= aRect.height - thumbRect.height;
+  tickMarkOrigin -=
+      LayoutDevicePoint(tickMarkSize.width, tickMarkSize.height) / 2;
+  auto tickMarkRect = LayoutDeviceRect(tickMarkOrigin, tickMarkSize);
+  for (auto tickMark : tickMarks) {
+    auto tickMarkOffset =
+        tickMarkDirection *
+        float(rangeFrame->GetDoubleAsFractionOfRange(tickMark));
+    ThemeDrawing::FillRect(aPaintData, tickMarkRect + tickMarkOffset,
+                           tickMarkColor);
+  }
+
+  // Draw the thumb on top.
+  const CSSCoord thumbBorderWidth = 2.0f;
+  auto [thumbColor, thumbBorderColor] =
+      ComputeRangeThumbColors(aState, aColors);
+
+  PaintStrokedCircle(aPaintData, thumbRect, thumbColor, thumbBorderColor,
+                     thumbBorderWidth, aDpiRatio);
+
+  if (aState.HasState(ElementState::FOCUSRING)) {
+    PaintRoundedFocusRect(aPaintData, aRect, aColors, aDpiRatio, radius, 1.0f);
+  }
+}
+
+template <typename PaintBackendData>
+void Theme::PaintProgress(nsIFrame* aFrame, PaintBackendData& aPaintData,
+                          const LayoutDeviceRect& aRect,
+                          const ElementState& aState, const Colors& aColors,
+                          DPIRatio aDpiRatio, bool aIsMeter) {
+  const CSSCoord borderWidth = 1.0f;
+  const CSSCoord radius = aIsMeter ? 6.0f : 3.0f;
+
+  LayoutDeviceRect rect(aRect);
+  const LayoutDeviceCoord thickness =
+      (aIsMeter ? kMeterHeight : kProgressbarHeight) * aDpiRatio;
+
+  const bool isHorizontal = !nsNativeTheme::IsVerticalProgress(aFrame);
+  if (isHorizontal) {
+    // Center it vertically.
+    rect.y += (rect.height - thickness) / 2;
+    rect.height = thickness;
+  } else {
+    // Center it horizontally.
+    rect.x += (rect.width - thickness) / 2;
+    rect.width = thickness;
+  }
+
+  {
+    // Paint the track, unclipped.
+    auto [backgroundColor, borderColor] = ComputeProgressTrackColors(aColors);
+    ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, rect, rect,
+                                             backgroundColor, borderColor,
+                                             borderWidth, radius, aDpiRatio);
+  }
+
+  // Now paint the chunk, clipped as needed.
+  LayoutDeviceRect clipRect = rect;
+  if (aState.HasState(ElementState::INDETERMINATE)) {
+    // For indeterminate progress, we paint an animated chunk of 1/3 of the
+    // progress size.
+    //
+    // Animation speed and math borrowed from GTK.
+    const LayoutDeviceCoord size = isHorizontal ? rect.width : rect.height;
+    const LayoutDeviceCoord barSize = size * 0.3333f;
+    const LayoutDeviceCoord travel = 2.0f * (size - barSize);
+
+    // Period equals to travel / pixelsPerMillisecond where pixelsPerMillisecond
+    // equals progressSize / 1000.0.  This is equivalent to 1600.
+    const unsigned kPeriod = 1600;
+
+    const int t = PR_IntervalToMilliseconds(PR_IntervalNow()) % kPeriod;
+    const LayoutDeviceCoord dx = travel * float(t) / float(kPeriod);
+    if (isHorizontal) {
+      rect.width = barSize;
+      rect.x += (dx < travel * .5f) ? dx : travel - dx;
+    } else {
+      rect.height = barSize;
+      rect.y += (dx < travel * .5f) ? dx : travel - dx;
+    }
+    clipRect = rect;
+    // Queue the next frame if needed.
+    if (!QueueAnimatedContentForRefresh(aFrame->GetContent(), 60)) {
+      NS_WARNING("Couldn't refresh indeterminate <progress>");
+    }
+  } else {
+    // This is the progress chunk, clip it to the right amount.
+    double position = [&] {
+      if (aIsMeter) {
+        auto* meter = dom::HTMLMeterElement::FromNode(aFrame->GetContent());
+        if (!meter) {
+          return 0.0;
+        }
+        return meter->Position();
+      }
+      auto* progress = dom::HTMLProgressElement::FromNode(aFrame->GetContent());
+      if (!progress) {
+        return 0.0;
+      }
+      return progress->Position();
+    }();
+    if (isHorizontal) {
+      double clipWidth = rect.width * position;
+      clipRect.width = clipWidth;
+      if (IsFrameRTL(aFrame)) {
+        clipRect.x += rect.width - clipWidth;
+      }
+    } else {
+      double clipHeight = rect.height * position;
+      clipRect.height = clipHeight;
+      clipRect.y += rect.height - clipHeight;
+    }
+  }
+
+  auto [backgroundColor, borderColor] =
+      aIsMeter ? ComputeMeterchunkColors(aState, aColors)
+               : ComputeProgressColors(aColors);
+  ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, rect, clipRect,
+                                           backgroundColor, borderColor,
+                                           borderWidth, radius, aDpiRatio);
+}
+
+template <typename PaintBackendData>
+void Theme::PaintButton(nsIFrame* aFrame, PaintBackendData& aPaintData,
+                        const LayoutDeviceRect& aRect,
+                        StyleAppearance aAppearance, const ElementState& aState,
+                        const Colors& aColors, DPIRatio aDpiRatio) {
+  const CSSCoord radius = 4.0f;
+  auto [backgroundColor, borderColor] =
+      ComputeButtonColors(aState, aColors, aFrame);
+
+  if (aAppearance == StyleAppearance::Toolbarbutton &&
+      (!aState.HasState(ElementState::HOVER) ||
+       aState.HasState(ElementState::DISABLED))) {
+    borderColor = sTransparent;
+  }
+
+  ThemeDrawing::PaintRoundedRectWithRadius(aPaintData, aRect, backgroundColor,
+                                           borderColor, kButtonBorderWidth,
+                                           radius, aDpiRatio);
+
+  if (aState.HasState(ElementState::FOCUSRING)) {
+    PaintRoundedFocusRect(aPaintData, aRect, aColors, aDpiRatio,
+                          radius + kButtonBorderWidth, -kButtonBorderWidth);
+  }
+}
+
+NS_IMETHODIMP
+Theme::DrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
+                            StyleAppearance aAppearance, const nsRect& aRect,
+                            const nsRect& /* aDirtyRect */,
+                            DrawOverflow aDrawOverflow) {
+  if (!DoDrawWidgetBackground(*aContext->GetDrawTarget(), aFrame, aAppearance,
+                              aRect, aDrawOverflow)) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+  return NS_OK;
+}
+
+bool Theme::CreateWebRenderCommandsForWidget(
+    mozilla::wr::DisplayListBuilder& aBuilder,
+    mozilla::wr::IpcResourceUpdateQueue& aResources,
+    const mozilla::layers::StackingContextHelper& aSc,
+    mozilla::layers::RenderRootStateManager* aManager, nsIFrame* aFrame,
+    StyleAppearance aAppearance, const nsRect& aRect) {
+  if (!StaticPrefs::widget_non_native_theme_webrender()) {
+    return false;
+  }
+  WebRenderBackendData data{aBuilder, aResources, aSc, aManager};
+  return DoDrawWidgetBackground(data, aFrame, aAppearance, aRect,
+                                DrawOverflow::Yes);
+}
+
+static LayoutDeviceRect ToSnappedRect(const nsRect& aRect,
+                                      nscoord aTwipsPerPixel, DrawTarget& aDt) {
+  return LayoutDeviceRect::FromUnknownRect(
+      NSRectToSnappedRect(aRect, aTwipsPerPixel, aDt));
+}
+
+static LayoutDeviceRect ToSnappedRect(const nsRect& aRect,
+                                      nscoord aTwipsPerPixel,
+                                      WebRenderBackendData& aDt) {
+  // TODO: Do we need to do any more snapping here?
+  return LayoutDeviceRect::FromAppUnits(aRect, aTwipsPerPixel);
+}
+
+static ScrollbarDrawing::ScrollbarKind ComputeScrollbarKind(
+    nsIFrame* aFrame, bool aIsHorizontal) {
+  if (aIsHorizontal) {
+    return ScrollbarDrawing::ScrollbarKind::Horizontal;
+  }
+  nsIFrame* scrollbar = ScrollbarDrawing::GetParentScrollbarFrame(aFrame);
+  if (NS_WARN_IF(!scrollbar)) {
+    return ScrollbarDrawing::ScrollbarKind::VerticalRight;
+  }
+  MOZ_ASSERT(scrollbar->IsScrollbarFrame());
+  nsIScrollbarMediator* sm =
+      static_cast<nsScrollbarFrame*>(scrollbar)->GetScrollbarMediator();
+  if (NS_WARN_IF(!sm)) {
+    return ScrollbarDrawing::ScrollbarKind::VerticalRight;
+  }
+  return sm->IsScrollbarOnRight()
+             ? ScrollbarDrawing::ScrollbarKind::VerticalRight
+             : ScrollbarDrawing::ScrollbarKind::VerticalLeft;
+}
+
+static ScrollbarDrawing::ScrollbarKind ComputeScrollbarKindForScrollCorner(
+    nsIFrame* aFrame) {
+  nsIScrollableFrame* sf = do_QueryFrame(aFrame->GetParent());
+  if (!sf) {
+    return ScrollbarDrawing::ScrollbarKind::VerticalRight;
+  }
+  return sf->IsScrollbarOnRight()
+             ? ScrollbarDrawing::ScrollbarKind::VerticalRight
+             : ScrollbarDrawing::ScrollbarKind::VerticalLeft;
+}
+
+template <typename PaintBackendData>
+bool Theme::DoDrawWidgetBackground(PaintBackendData& aPaintData,
+                                   nsIFrame* aFrame,
+                                   StyleAppearance aAppearance,
+                                   const nsRect& aRect,
+                                   DrawOverflow aDrawOverflow) {
+  static_assert(std::is_same_v<PaintBackendData, DrawTarget> ||
+                std::is_same_v<PaintBackendData, WebRenderBackendData>);
+
+  const nsPresContext* pc = aFrame->PresContext();
+  const nscoord twipsPerPixel = pc->AppUnitsPerDevPixel();
+  const auto devPxRect = ToSnappedRect(aRect, twipsPerPixel, aPaintData);
+
+  const DocumentState docState = pc->Document()->State();
+  ElementState elementState = GetContentState(aFrame, aAppearance);
+  // Paint the outline iff we're asked to draw overflow and we have
+  // outline-style: auto.
+  if (aDrawOverflow == DrawOverflow::Yes &&
+      aFrame->StyleOutline()->mOutlineStyle.IsAuto()) {
+    elementState |= ElementState::FOCUSRING;
+  } else {
+    elementState &= ~ElementState::FOCUSRING;
+  }
+
+  // Hack to avoid skia fuzziness: Add a dummy clip if the widget doesn't
+  // overflow devPxRect.
+  Maybe<AutoClipRect> maybeClipRect;
+  if constexpr (std::is_same_v<PaintBackendData, DrawTarget>) {
+    if (aAppearance != StyleAppearance::FocusOutline &&
+        aAppearance != StyleAppearance::Range &&
+        !elementState.HasState(ElementState::FOCUSRING)) {
+      maybeClipRect.emplace(aPaintData, devPxRect);
+    }
+  }
+
+  const Colors colors(aFrame, aAppearance);
+  DPIRatio dpiRatio = GetDPIRatio(aFrame, aAppearance);
+
+  switch (aAppearance) {
+    case StyleAppearance::Radio: {
+      auto rect = CheckBoxRadioRect(devPxRect);
+      PaintRadioControl(aPaintData, rect, elementState, colors, dpiRatio);
+      break;
+    }
+    case StyleAppearance::Checkbox: {
+      if constexpr (std::is_same_v<PaintBackendData, WebRenderBackendData>) {
+        // TODO: Need to figure out how to best draw this using WR.
+        return false;
+      } else {
+        auto rect = CheckBoxRadioRect(devPxRect);
+        PaintCheckboxControl(aPaintData, rect, elementState, colors, dpiRatio);
+      }
+      break;
+    }
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::NumberInput:
+      PaintTextField(aPaintData, devPxRect, elementState, colors, dpiRatio);
+      break;
+    case StyleAppearance::Listbox:
+      PaintListbox(aPaintData, devPxRect, elementState, colors, dpiRatio);
+      break;
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Menulist:
+      PaintMenulist(aPaintData, devPxRect, elementState, colors, dpiRatio);
+      break;
+    case StyleAppearance::MozMenulistArrowButton:
+      if constexpr (std::is_same_v<PaintBackendData, WebRenderBackendData>) {
+        // TODO: Need to figure out how to best draw this using WR.
+        return false;
+      } else {
+        PaintMenulistArrow(aFrame, aPaintData, devPxRect);
+      }
+      break;
+    case StyleAppearance::Tooltip: {
+      const CSSCoord strokeWidth(1.0f);
+      const CSSCoord strokeRadius(2.0f);
+      ThemeDrawing::PaintRoundedRectWithRadius(
+          aPaintData, devPxRect,
+          colors.System(StyleSystemColor::Infobackground),
+          colors.System(StyleSystemColor::Infotext), strokeWidth, strokeRadius,
+          dpiRatio);
+      break;
+    }
+    case StyleAppearance::SpinnerUpbutton:
+    case StyleAppearance::SpinnerDownbutton:
+      if constexpr (std::is_same_v<PaintBackendData, WebRenderBackendData>) {
+        // TODO: Need to figure out how to best draw this using WR.
+        return false;
+      } else {
+        PaintSpinnerButton(aFrame, aPaintData, devPxRect, elementState,
+                           aAppearance, colors, dpiRatio);
+      }
+      break;
+    case StyleAppearance::Range:
+      PaintRange(aFrame, aPaintData, devPxRect, elementState, colors, dpiRatio,
+                 IsRangeHorizontal(aFrame));
+      break;
+    case StyleAppearance::RangeThumb:
+      // Painted as part of StyleAppearance::Range.
+      break;
+    case StyleAppearance::ProgressBar:
+      PaintProgress(aFrame, aPaintData, devPxRect, elementState, colors,
+                    dpiRatio,
+                    /* aIsMeter = */ false);
+      break;
+    case StyleAppearance::Progresschunk:
+      /* Painted as part of the progress bar */
+      break;
+    case StyleAppearance::Meter:
+      PaintProgress(aFrame, aPaintData, devPxRect, elementState, colors,
+                    dpiRatio,
+                    /* aIsMeter = */ true);
+      break;
+    case StyleAppearance::Meterchunk:
+      /* Painted as part of the meter bar */
+      break;
+    case StyleAppearance::ScrollbarthumbHorizontal:
+    case StyleAppearance::ScrollbarthumbVertical: {
+      bool isHorizontal =
+          aAppearance == StyleAppearance::ScrollbarthumbHorizontal;
+      auto kind = ComputeScrollbarKind(aFrame, isHorizontal);
+      return GetScrollbarDrawing().PaintScrollbarThumb(
+          aPaintData, devPxRect, kind, aFrame,
+          *nsLayoutUtils::StyleForScrollbar(aFrame), elementState, docState,
+          colors, dpiRatio);
+    }
+    case StyleAppearance::ScrollbartrackHorizontal:
+    case StyleAppearance::ScrollbartrackVertical: {
+      bool isHorizontal =
+          aAppearance == StyleAppearance::ScrollbartrackHorizontal;
+      auto kind = ComputeScrollbarKind(aFrame, isHorizontal);
+      return GetScrollbarDrawing().PaintScrollbarTrack(
+          aPaintData, devPxRect, kind, aFrame,
+          *nsLayoutUtils::StyleForScrollbar(aFrame), docState, colors,
+          dpiRatio);
+    }
+    case StyleAppearance::ScrollbarHorizontal:
+    case StyleAppearance::ScrollbarVertical: {
+      bool isHorizontal = aAppearance == StyleAppearance::ScrollbarHorizontal;
+      auto kind = ComputeScrollbarKind(aFrame, isHorizontal);
+      return GetScrollbarDrawing().PaintScrollbar(
+          aPaintData, devPxRect, kind, aFrame,
+          *nsLayoutUtils::StyleForScrollbar(aFrame), elementState, docState,
+          colors, dpiRatio);
+    }
+    case StyleAppearance::Scrollcorner: {
+      auto kind = ComputeScrollbarKindForScrollCorner(aFrame);
+      return GetScrollbarDrawing().PaintScrollCorner(
+          aPaintData, devPxRect, kind, aFrame,
+          *nsLayoutUtils::StyleForScrollbar(aFrame), docState, colors,
+          dpiRatio);
+    }
+    case StyleAppearance::ScrollbarbuttonUp:
+    case StyleAppearance::ScrollbarbuttonDown:
+    case StyleAppearance::ScrollbarbuttonLeft:
+    case StyleAppearance::ScrollbarbuttonRight: {
+      // For scrollbar-width:thin, we don't display the buttons.
+      if (!ScrollbarDrawing::IsScrollbarWidthThin(aFrame)) {
+        if constexpr (std::is_same_v<PaintBackendData, WebRenderBackendData>) {
+          // TODO: Need to figure out how to best draw this using WR.
+          return false;
+        } else {
+          bool isHorizontal =
+              aAppearance == StyleAppearance::ScrollbarbuttonLeft ||
+              aAppearance == StyleAppearance::ScrollbarbuttonRight;
+          auto kind = ComputeScrollbarKind(aFrame, isHorizontal);
+          GetScrollbarDrawing().PaintScrollbarButton(
+              aPaintData, aAppearance, devPxRect, kind, aFrame,
+              *nsLayoutUtils::StyleForScrollbar(aFrame), elementState, docState,
+              colors, dpiRatio);
+        }
+      }
+      break;
+    }
+    case StyleAppearance::Button:
+    case StyleAppearance::Toolbarbutton:
+      PaintButton(aFrame, aPaintData, devPxRect, aAppearance, elementState,
+                  colors, dpiRatio);
+      break;
+    case StyleAppearance::FocusOutline:
+      PaintAutoStyleOutline(aFrame, aPaintData, devPxRect, colors, dpiRatio);
+      break;
+    default:
+      // Various appearance values are used for XUL elements.  Normally these
+      // will not be available in content documents (and thus in the content
+      // processes where the native basic theme can be used), but tests are
+      // run with the remote XUL pref enabled and so we can get in here.  So
+      // we just return an error rather than assert.
+      return false;
+  }
+
+  return true;
+}
+
+template <typename PaintBackendData>
+void Theme::PaintAutoStyleOutline(nsIFrame* aFrame,
+                                  PaintBackendData& aPaintData,
+                                  const LayoutDeviceRect& aRect,
+                                  const Colors& aColors, DPIRatio aDpiRatio) {
+  const auto& accentColor = aColors.Accent();
+  const bool solid = StaticPrefs::widget_non_native_theme_solid_outline_style();
+  LayoutDeviceCoord strokeWidth(ThemeDrawing::SnapBorderWidth(2.0f, aDpiRatio));
+
+  LayoutDeviceRect rect(aRect);
+  rect.Inflate(strokeWidth);
+
+  const nscoord a2d = aFrame->PresContext()->AppUnitsPerDevPixel();
+  nscoord cssOffset = aFrame->StyleOutline()->mOutlineOffset.ToAppUnits();
+  nscoord cssRadii[8] = {0};
+  if (!aFrame->GetBorderRadii(cssRadii)) {
+    const auto twoPixels = 2 * AppUnitsPerCSSPixel();
+    const nscoord radius =
+        cssOffset >= 0 ? twoPixels : std::max(twoPixels + cssOffset, 0);
+    cssOffset = -twoPixels;
+    for (auto& r : cssRadii) {
+      r = radius;
+    }
+  }
+
+  auto offset = LayoutDevicePixel::FromAppUnits(cssOffset, a2d);
+  RectCornerRadii innerRadii;
+  nsCSSRendering::ComputePixelRadii(cssRadii, a2d, &innerRadii);
+
+  // NOTE(emilio): This doesn't use PaintRoundedRectWithRadius because we need
+  // to support arbitrary radii.
+  auto DrawRect = [&](const sRGBColor& aColor) {
+    RectCornerRadii outerRadii;
+    if constexpr (std::is_same_v<PaintBackendData, WebRenderBackendData>) {
+      const Float widths[4] = {strokeWidth + offset, strokeWidth + offset,
+                               strokeWidth + offset, strokeWidth + offset};
+      nsCSSBorderRenderer::ComputeOuterRadii(innerRadii, widths, &outerRadii);
+      const auto dest = wr::ToLayoutRect(rect);
+      const auto side =
+          wr::ToBorderSide(ToDeviceColor(aColor), StyleBorderStyle::Solid);
+      const wr::BorderSide sides[4] = {side, side, side, side};
+      const bool kBackfaceIsVisible = true;
+      const auto wrWidths = wr::ToBorderWidths(strokeWidth, strokeWidth,
+                                               strokeWidth, strokeWidth);
+      const auto wrRadius = wr::ToBorderRadius(outerRadii);
+      aPaintData.mBuilder.PushBorder(dest, dest, kBackfaceIsVisible, wrWidths,
+                                     {sides, 4}, wrRadius);
+    } else {
+      const LayoutDeviceCoord halfWidth = strokeWidth * 0.5f;
+      const Float widths[4] = {halfWidth + offset, halfWidth + offset,
+                               halfWidth + offset, halfWidth + offset};
+      nsCSSBorderRenderer::ComputeOuterRadii(innerRadii, widths, &outerRadii);
+      LayoutDeviceRect dest(rect);
+      dest.Deflate(halfWidth);
+      RefPtr<Path> path =
+          MakePathForRoundedRect(aPaintData, dest.ToUnknownRect(), outerRadii);
+      aPaintData.Stroke(path, ColorPattern(ToDeviceColor(aColor)),
+                        StrokeOptions(strokeWidth));
+    }
+  };
+
+  auto primaryColor = aColors.HighContrast()
+                          ? aColors.System(StyleSystemColor::Selecteditem)
+                          : accentColor.Get();
+  DrawRect(primaryColor);
+
+  if (solid) {
+    return;
+  }
+
+  offset += strokeWidth;
+
+  strokeWidth =
+      LayoutDeviceCoord(ThemeDrawing::SnapBorderWidth(1.0f, aDpiRatio));
+  rect.Inflate(strokeWidth);
+
+  auto secondaryColor = aColors.HighContrast()
+                            ? aColors.System(StyleSystemColor::Canvastext)
+                            : accentColor.GetForeground();
+  DrawRect(secondaryColor);
+}
+
+LayoutDeviceIntMargin Theme::GetWidgetBorder(nsDeviceContext* aContext,
+                                             nsIFrame* aFrame,
+                                             StyleAppearance aAppearance) {
+  switch (aAppearance) {
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Button:
+    case StyleAppearance::Toolbarbutton:
+      // Return the border size from the UA sheet, even though what we paint
+      // doesn't actually match that. We know this is the UA sheet border
+      // because we disable native theming when different border widths are
+      // specified by authors, see Theme::IsWidgetStyled.
+      //
+      // The Rounded() bit is technically redundant, but needed to appease the
+      // type system, we should always end up with full device pixels due to
+      // round_border_to_device_pixels at style time.
+      return LayoutDeviceIntMargin::FromAppUnits(
+                 aFrame->StyleBorder()->GetComputedBorder(),
+                 aFrame->PresContext()->AppUnitsPerDevPixel())
+          .Rounded();
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Radio: {
+      DPIRatio dpiRatio = GetDPIRatio(aFrame, aAppearance);
+      LayoutDeviceIntCoord w =
+          ThemeDrawing::SnapBorderWidth(kCheckboxRadioBorderWidth, dpiRatio);
+      return LayoutDeviceIntMargin(w, w, w, w);
+    }
+    default:
+      return LayoutDeviceIntMargin();
+  }
+}
+
+bool Theme::GetWidgetPadding(nsDeviceContext* aContext, nsIFrame* aFrame,
+                             StyleAppearance aAppearance,
+                             LayoutDeviceIntMargin* aResult) {
+  switch (aAppearance) {
+    // Radios and checkboxes return a fixed size in GetMinimumWidgetSize
+    // and have a meaningful baseline, so they can't have
+    // author-specified padding.
+    case StyleAppearance::Radio:
+    case StyleAppearance::Checkbox:
+      aResult->SizeTo(0, 0, 0, 0);
+      return true;
+    default:
+      break;
+  }
+  return false;
+}
+
+bool Theme::GetWidgetOverflow(nsDeviceContext* aContext, nsIFrame* aFrame,
+                              StyleAppearance aAppearance,
+                              nsRect* aOverflowRect) {
+  CSSIntMargin overflow;
+  switch (aAppearance) {
+    case StyleAppearance::FocusOutline: {
+      // 2px * one segment, or 2px + 1px
+      const auto width =
+          StaticPrefs::widget_non_native_theme_solid_outline_style() ? 2 : 3;
+      overflow.SizeTo(width, width, width, width);
+      break;
+    }
+    case StyleAppearance::Radio:
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Range:
+      // 2px for each outline segment, plus 1px separation, plus we paint with a
+      // 1px extra offset, so 6px.
+      overflow.SizeTo(6, 6, 6, 6);
+      break;
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Listbox:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::Button:
+    case StyleAppearance::Toolbarbutton:
+      // 2px for each segment, plus 1px separation, but we paint 1px inside
+      // the border area so 4px overflow.
+      overflow.SizeTo(4, 4, 4, 4);
+      break;
+    default:
+      return false;
+  }
+
+  // TODO: This should convert from device pixels to app units, not from CSS
+  // pixels. And it should take the dpi ratio into account.
+  // Using CSS pixels can cause the overflow to be too small if the page is
+  // zoomed out.
+  aOverflowRect->Inflate(CSSPixel::ToAppUnits(overflow));
+  return true;
+}
+
+LayoutDeviceIntCoord Theme::GetScrollbarSize(const nsPresContext* aPresContext,
+                                             StyleScrollbarWidth aWidth,
+                                             Overlay aOverlay) {
+  return GetScrollbarDrawing().GetScrollbarSize(aPresContext, aWidth, aOverlay);
+}
+
+nscoord Theme::GetCheckboxRadioPrefSize() {
+  return CSSPixel::ToAppUnits(kCheckboxRadioContentBoxSize);
+}
+
+/* static */
+UniquePtr<ScrollbarDrawing> Theme::ScrollbarStyle() {
+  switch (StaticPrefs::widget_non_native_theme_scrollbar_style()) {
+    case 1:
+      return MakeUnique<ScrollbarDrawingCocoa>();
+    case 2:
+      return MakeUnique<ScrollbarDrawingGTK>();
+    case 3:
+      return MakeUnique<ScrollbarDrawingAndroid>();
+    case 4:
+      return MakeUnique<ScrollbarDrawingWin>();
+    case 5:
+      return MakeUnique<ScrollbarDrawingWin11>();
+    default:
+      break;
+  }
+    // Default to native scrollbar style for each platform.
+#ifdef XP_WIN
+  if (IsWin11OrLater()) {
+    return MakeUnique<ScrollbarDrawingWin11>();
+  }
+  return MakeUnique<ScrollbarDrawingWin>();
+#elif MOZ_WIDGET_COCOA
+  return MakeUnique<ScrollbarDrawingCocoa>();
+#elif MOZ_WIDGET_GTK
+  return MakeUnique<ScrollbarDrawingGTK>();
+#elif ANDROID
+  return MakeUnique<ScrollbarDrawingAndroid>();
+#else
+#  error "Unknown platform, need scrollbar implementation."
+#endif
+}
+
+LayoutDeviceIntSize Theme::GetMinimumWidgetSize(nsPresContext* aPresContext,
+                                                nsIFrame* aFrame,
+                                                StyleAppearance aAppearance) {
+  DPIRatio dpiRatio = GetDPIRatio(aFrame, aAppearance);
+
+  if (IsWidgetScrollbarPart(aAppearance)) {
+    return GetScrollbarDrawing().GetMinimumWidgetSize(aPresContext, aAppearance,
+                                                      aFrame);
+  }
+
+  LayoutDeviceIntSize result;
+  switch (aAppearance) {
+    case StyleAppearance::RangeThumb:
+      result.SizeTo((kMinimumRangeThumbSize * dpiRatio).Rounded(),
+                    (kMinimumRangeThumbSize * dpiRatio).Rounded());
+      break;
+    case StyleAppearance::MozMenulistArrowButton:
+      result.width = (kMinimumDropdownArrowButtonWidth * dpiRatio).Rounded();
+      break;
+    case StyleAppearance::SpinnerUpbutton:
+    case StyleAppearance::SpinnerDownbutton:
+      result.width = (kMinimumSpinnerButtonWidth * dpiRatio).Rounded();
+      result.height = (kMinimumSpinnerButtonHeight * dpiRatio).Rounded();
+      break;
+    default:
+      break;
+  }
+  return result;
+}
+
+nsITheme::Transparency Theme::GetWidgetTransparency(
+    nsIFrame* aFrame, StyleAppearance aAppearance) {
+  if (auto scrollbar = GetScrollbarDrawing().GetScrollbarPartTransparency(
+          aFrame, aAppearance)) {
+    return *scrollbar;
+  }
+  if (aAppearance == StyleAppearance::Tooltip) {
+    // We draw a rounded rect, so we need transparency.
+    return eTransparent;
+  }
+  return eUnknownTransparency;
+}
+
+NS_IMETHODIMP
+Theme::WidgetStateChanged(nsIFrame* aFrame, StyleAppearance aAppearance,
+                          nsAtom* aAttribute, bool* aShouldRepaint,
+                          const nsAttrValue* aOldValue) {
+  if (!aAttribute) {
+    // Hover/focus/active changed.  Always repaint.
+    *aShouldRepaint = true;
+  } else {
+    // Check the attribute to see if it's relevant.
+    // disabled, checked, dlgtype, default, etc.
+    *aShouldRepaint = false;
+    if (aAttribute == nsGkAtoms::disabled || aAttribute == nsGkAtoms::checked ||
+        aAttribute == nsGkAtoms::selected ||
+        aAttribute == nsGkAtoms::visuallyselected ||
+        aAttribute == nsGkAtoms::menuactive ||
+        aAttribute == nsGkAtoms::sortDirection ||
+        aAttribute == nsGkAtoms::focused || aAttribute == nsGkAtoms::_default ||
+        aAttribute == nsGkAtoms::open || aAttribute == nsGkAtoms::hover) {
+      *aShouldRepaint = true;
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+Theme::ThemeChanged() { return NS_OK; }
+
+bool Theme::WidgetAppearanceDependsOnWindowFocus(StyleAppearance aAppearance) {
+  return IsWidgetScrollbarPart(aAppearance);
+}
+
+nsITheme::ThemeGeometryType Theme::ThemeGeometryTypeForWidget(
+    nsIFrame* aFrame, StyleAppearance aAppearance) {
+  return eThemeGeometryTypeUnknown;
+}
+
+bool Theme::ThemeSupportsWidget(nsPresContext* aPresContext, nsIFrame* aFrame,
+                                StyleAppearance aAppearance) {
+  switch (aAppearance) {
+    case StyleAppearance::Radio:
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::FocusOutline:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Range:
+    case StyleAppearance::RangeThumb:
+    case StyleAppearance::ProgressBar:
+    case StyleAppearance::Progresschunk:
+    case StyleAppearance::Meter:
+    case StyleAppearance::Meterchunk:
+    case StyleAppearance::ScrollbarbuttonUp:
+    case StyleAppearance::ScrollbarbuttonDown:
+    case StyleAppearance::ScrollbarbuttonLeft:
+    case StyleAppearance::ScrollbarbuttonRight:
+    case StyleAppearance::ScrollbarthumbHorizontal:
+    case StyleAppearance::ScrollbarthumbVertical:
+    case StyleAppearance::ScrollbartrackHorizontal:
+    case StyleAppearance::ScrollbartrackVertical:
+    case StyleAppearance::ScrollbarHorizontal:
+    case StyleAppearance::ScrollbarVertical:
+    case StyleAppearance::Scrollcorner:
+    case StyleAppearance::Button:
+    case StyleAppearance::Toolbarbutton:
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::MozMenulistArrowButton:
+    case StyleAppearance::SpinnerUpbutton:
+    case StyleAppearance::SpinnerDownbutton:
+    case StyleAppearance::Tooltip:
+      return !IsWidgetStyled(aPresContext, aFrame, aAppearance);
+    default:
+      return false;
+  }
+}
+
+bool Theme::WidgetIsContainer(StyleAppearance aAppearance) {
+  switch (aAppearance) {
+    case StyleAppearance::MozMenulistArrowButton:
+    case StyleAppearance::Radio:
+    case StyleAppearance::Checkbox:
+      return false;
+    default:
+      return true;
+  }
+}
+
+bool Theme::ThemeDrawsFocusForWidget(nsIFrame*, StyleAppearance) {
+  return true;
+}
+
+bool Theme::ThemeNeedsComboboxDropmarker() { return true; }
+
+bool Theme::ThemeSupportsScrollbarButtons() {
+  return GetScrollbarDrawing().ShouldDrawScrollbarButtons();
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/Theme.h b/widget/Theme.h
new file mode 100644
index 0000000000..c09c414056
--- /dev/null
+++ b/widget/Theme.h
@@ -0,0 +1,208 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_Theme_h
+#define mozilla_widget_Theme_h
+
+#include "Units.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Rect.h"
+#include "mozilla/gfx/Types.h"
+#include "nsITheme.h"
+#include "nsNativeTheme.h"
+#include "ScrollbarDrawing.h"
+
+namespace mozilla {
+
+enum class StyleSystemColor : uint8_t;
+
+namespace widget {
+
+class Theme : protected nsNativeTheme, public nsITheme {
+ protected:
+  using sRGBColor = gfx::sRGBColor;
+  using DrawTarget = gfx::DrawTarget;
+  using Path = gfx::Path;
+  using Rect = gfx::Rect;
+  using Point = gfx::Point;
+  using RectCornerRadii = gfx::RectCornerRadii;
+  using Colors = ThemeColors;
+  using AccentColor = ThemeAccentColor;
+  using ElementState = dom::ElementState;
+
+ public:
+  explicit Theme(UniquePtr<ScrollbarDrawing>&& aScrollbarDrawing)
+      : mScrollbarDrawing(std::move(aScrollbarDrawing)) {
+    mScrollbarDrawing->RecomputeScrollbarParams();
+  }
+
+  static void Init();
+  static void Shutdown();
+  static void LookAndFeelChanged();
+
+  using DPIRatio = CSSToLayoutDeviceScale;
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // The nsITheme interface.
+  NS_IMETHOD DrawWidgetBackground(gfxContext* aContext, nsIFrame*,
+                                  StyleAppearance, const nsRect& aRect,
+                                  const nsRect& aDirtyRect,
+                                  DrawOverflow) override;
+
+  bool CreateWebRenderCommandsForWidget(
+      wr::DisplayListBuilder& aBuilder, wr::IpcResourceUpdateQueue& aResources,
+      const layers::StackingContextHelper& aSc,
+      layers::RenderRootStateManager* aManager, nsIFrame*, StyleAppearance,
+      const nsRect& aRect) override;
+
+  // PaintBackendData will be either a DrawTarget, or a WebRenderBackendData.
+  //
+  // The return value represents whether the widget could be painted with the
+  // given back-end.
+  template <typename PaintBackendData>
+  bool DoDrawWidgetBackground(PaintBackendData&, nsIFrame*, StyleAppearance,
+                              const nsRect&, DrawOverflow);
+
+  [[nodiscard]] LayoutDeviceIntMargin GetWidgetBorder(nsDeviceContext* aContext,
+                                                      nsIFrame*,
+                                                      StyleAppearance) override;
+  bool GetWidgetPadding(nsDeviceContext* aContext, nsIFrame*, StyleAppearance,
+                        LayoutDeviceIntMargin* aResult) override;
+  bool GetWidgetOverflow(nsDeviceContext* aContext, nsIFrame*, StyleAppearance,
+                         nsRect* aOverflowRect) override;
+  LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*, nsIFrame*,
+                                           StyleAppearance) override;
+  Transparency GetWidgetTransparency(nsIFrame*, StyleAppearance) override;
+  NS_IMETHOD WidgetStateChanged(nsIFrame*, StyleAppearance, nsAtom* aAttribute,
+                                bool* aShouldRepaint,
+                                const nsAttrValue* aOldValue) override;
+  NS_IMETHOD ThemeChanged() override;
+  bool WidgetAppearanceDependsOnWindowFocus(StyleAppearance) override;
+  /*bool NeedToClearBackgroundBehindWidget(
+      nsIFrame*, StyleAppearance) override;*/
+  ThemeGeometryType ThemeGeometryTypeForWidget(nsIFrame*,
+                                               StyleAppearance) override;
+  bool ThemeSupportsWidget(nsPresContext*, nsIFrame*, StyleAppearance) override;
+  bool WidgetIsContainer(StyleAppearance) override;
+  bool ThemeDrawsFocusForWidget(nsIFrame*, StyleAppearance) override;
+  bool ThemeNeedsComboboxDropmarker() override;
+
+  LayoutDeviceIntCoord GetScrollbarSize(const nsPresContext*,
+                                        StyleScrollbarWidth, Overlay) final;
+
+  nscoord GetCheckboxRadioPrefSize() override;
+
+  static UniquePtr<ScrollbarDrawing> ScrollbarStyle();
+
+ protected:
+  virtual ~Theme() = default;
+
+  DPIRatio GetDPIRatio(nsPresContext*, StyleAppearance);
+  DPIRatio GetDPIRatio(nsIFrame*, StyleAppearance);
+
+  std::tuple<sRGBColor, sRGBColor, sRGBColor> ComputeCheckboxColors(
+      const ElementState&, StyleAppearance, const Colors&);
+  enum class OutlineCoversBorder : bool { No, Yes };
+  sRGBColor ComputeBorderColor(const ElementState&, const Colors&,
+                               OutlineCoversBorder);
+
+  std::pair<sRGBColor, sRGBColor> ComputeButtonColors(const ElementState&,
+                                                      const Colors&,
+                                                      nsIFrame* = nullptr);
+  std::pair<sRGBColor, sRGBColor> ComputeTextfieldColors(const ElementState&,
+                                                         const Colors&,
+                                                         OutlineCoversBorder);
+  std::pair<sRGBColor, sRGBColor> ComputeRangeProgressColors(
+      const ElementState&, const Colors&);
+  std::pair<sRGBColor, sRGBColor> ComputeRangeTrackColors(const ElementState&,
+                                                          const Colors&);
+  std::pair<sRGBColor, sRGBColor> ComputeRangeThumbColors(const ElementState&,
+                                                          const Colors&);
+  std::pair<sRGBColor, sRGBColor> ComputeProgressColors(const Colors&);
+  std::pair<sRGBColor, sRGBColor> ComputeProgressTrackColors(const Colors&);
+  std::pair<sRGBColor, sRGBColor> ComputeMeterchunkColors(
+      const ElementState& aMeterState, const Colors&);
+  std::array<sRGBColor, 3> ComputeFocusRectColors(const Colors&);
+
+  template <typename PaintBackendData>
+  void PaintRoundedFocusRect(PaintBackendData&, const LayoutDeviceRect&,
+                             const Colors&, DPIRatio, CSSCoord aRadius,
+                             CSSCoord aOffset);
+  template <typename PaintBackendData>
+  void PaintAutoStyleOutline(nsIFrame*, PaintBackendData&,
+                             const LayoutDeviceRect&, const Colors&, DPIRatio);
+
+  void PaintCheckboxControl(DrawTarget& aDrawTarget, const LayoutDeviceRect&,
+                            const ElementState&, const Colors&, DPIRatio);
+  void PaintCheckMark(DrawTarget&, const LayoutDeviceRect&, const sRGBColor&);
+  void PaintIndeterminateMark(DrawTarget&, const LayoutDeviceRect&,
+                              const sRGBColor&);
+
+  template <typename PaintBackendData>
+  void PaintStrokedCircle(PaintBackendData&, const LayoutDeviceRect&,
+                          const sRGBColor& aBackgroundColor,
+                          const sRGBColor& aBorderColor,
+                          const CSSCoord aBorderWidth, DPIRatio);
+  void PaintCircleShadow(DrawTarget&, const LayoutDeviceRect& aBoxRect,
+                         const LayoutDeviceRect& aClipRect, float aShadowAlpha,
+                         const CSSPoint& aShadowOffset,
+                         CSSCoord aShadowBlurStdDev, DPIRatio);
+  void PaintCircleShadow(WebRenderBackendData&,
+                         const LayoutDeviceRect& aBoxRect,
+                         const LayoutDeviceRect& aClipRect, float aShadowAlpha,
+                         const CSSPoint& aShadowOffset,
+                         CSSCoord aShadowBlurStdDev, DPIRatio);
+  template <typename PaintBackendData>
+  void PaintRadioControl(PaintBackendData&, const LayoutDeviceRect&,
+                         const ElementState&, const Colors&, DPIRatio);
+  template <typename PaintBackendData>
+  void PaintRadioCheckmark(PaintBackendData&, const LayoutDeviceRect&,
+                           const ElementState&, DPIRatio);
+  template <typename PaintBackendData>
+  void PaintTextField(PaintBackendData&, const LayoutDeviceRect&,
+                      const ElementState&, const Colors&, DPIRatio);
+  template <typename PaintBackendData>
+  void PaintListbox(PaintBackendData&, const LayoutDeviceRect&,
+                    const ElementState&, const Colors&, DPIRatio);
+  template <typename PaintBackendData>
+  void PaintMenulist(PaintBackendData&, const LayoutDeviceRect&,
+                     const ElementState&, const Colors&, DPIRatio);
+  void PaintMenulistArrow(nsIFrame*, DrawTarget&, const LayoutDeviceRect&);
+  void PaintSpinnerButton(nsIFrame*, DrawTarget&, const LayoutDeviceRect&,
+                          const ElementState&, StyleAppearance, const Colors&,
+                          DPIRatio);
+  template <typename PaintBackendData>
+  void PaintRange(nsIFrame*, PaintBackendData&, const LayoutDeviceRect&,
+                  const ElementState&, const Colors&, DPIRatio,
+                  bool aHorizontal);
+  template <typename PaintBackendData>
+  void PaintProgress(nsIFrame*, PaintBackendData&, const LayoutDeviceRect&,
+                     const ElementState&, const Colors&, DPIRatio,
+                     bool aIsMeter);
+  template <typename PaintBackendData>
+  void PaintButton(nsIFrame*, PaintBackendData&, const LayoutDeviceRect&,
+                   StyleAppearance, const ElementState&, const Colors&,
+                   DPIRatio);
+
+  static void PrefChangedCallback(const char*, void*) {
+    LookAndFeel::NotifyChangedAllWindows(ThemeChangeKind::Layout);
+  }
+
+  void SetScrollbarDrawing(UniquePtr<ScrollbarDrawing>&& aScrollbarDrawing) {
+    mScrollbarDrawing = std::move(aScrollbarDrawing);
+    mScrollbarDrawing->RecomputeScrollbarParams();
+  }
+  ScrollbarDrawing& GetScrollbarDrawing() const { return *mScrollbarDrawing; }
+  UniquePtr<ScrollbarDrawing> mScrollbarDrawing;
+
+  bool ThemeSupportsScrollbarButtons() override;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/ThemeChangeKind.h b/widget/ThemeChangeKind.h
new file mode 100644
index 0000000000..2300ea648b
--- /dev/null
+++ b/widget/ThemeChangeKind.h
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_ThemeChangeKind
+#define mozilla_widget_ThemeChangeKind
+
+#include "mozilla/TypedEnumBits.h"
+
+namespace mozilla::widget {
+
+enum class ThemeChangeKind : uint8_t {
+  // This is the cheapest change, no need to forcibly recompute style and/or
+  // layout.
+  MediaQueriesOnly = 0,
+  // Style needs to forcibly be recomputed because some of the stuff that may
+  // have changed, like system colors, are reflected in the computed style but
+  // not in the specified style.
+  Style = 1 << 0,
+  // Layout needs to forcibly be recomputed because some of the stuff that may
+  // have changed is layout-dependent, like system font.
+  Layout = 1 << 1,
+  // The union of the two flags above.
+  StyleAndLayout = Style | Layout,
+  // For IPC serialization purposes.
+  AllBits = Style | Layout,
+};
+
+MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(ThemeChangeKind)
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/ThemeCocoa.cpp b/widget/ThemeCocoa.cpp
new file mode 100644
index 0000000000..733c215991
--- /dev/null
+++ b/widget/ThemeCocoa.cpp
@@ -0,0 +1,63 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ThemeCocoa.h"
+
+#include "cocoa/MacThemeGeometryType.h"
+#include "gfxPlatform.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/gfx/Helpers.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/ServoStyleConsts.h"
+
+namespace mozilla::widget {
+
+LayoutDeviceIntSize ThemeCocoa::GetMinimumWidgetSize(
+    nsPresContext* aPresContext, nsIFrame* aFrame,
+    StyleAppearance aAppearance) {
+  if (aAppearance == StyleAppearance::MozMenulistArrowButton) {
+    auto size =
+        GetScrollbarSize(aPresContext, StyleScrollbarWidth::Auto, Overlay::No);
+    return {size, size};
+  }
+  return Theme::GetMinimumWidgetSize(aPresContext, aFrame, aAppearance);
+}
+
+NS_IMETHODIMP
+ThemeCocoa::DrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
+                                 StyleAppearance aAppearance,
+                                 const nsRect& aRect, const nsRect& aDirtyRect,
+                                 DrawOverflow aDrawOverflow) {
+  switch (aAppearance) {
+    case StyleAppearance::Tooltip:
+      // Cocoa tooltip background and border are already drawn by the
+      // OS window server.
+      return NS_OK;
+    default:
+      break;
+  }
+  return Theme::DrawWidgetBackground(aContext, aFrame, aAppearance, aRect,
+                                     aDirtyRect, aDrawOverflow);
+}
+
+bool ThemeCocoa::CreateWebRenderCommandsForWidget(
+    mozilla::wr::DisplayListBuilder& aBuilder,
+    mozilla::wr::IpcResourceUpdateQueue& aResources,
+    const mozilla::layers::StackingContextHelper& aSc,
+    mozilla::layers::RenderRootStateManager* aManager, nsIFrame* aFrame,
+    StyleAppearance aAppearance, const nsRect& aRect) {
+  switch (aAppearance) {
+    case StyleAppearance::Tooltip:
+      // Cocoa tooltip background and border are already drawn by the
+      // OS window server.
+      return true;
+    default:
+      break;
+  }
+  return Theme::CreateWebRenderCommandsForWidget(
+      aBuilder, aResources, aSc, aManager, aFrame, aAppearance, aRect);
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/ThemeCocoa.h b/widget/ThemeCocoa.h
new file mode 100644
index 0000000000..f846766f37
--- /dev/null
+++ b/widget/ThemeCocoa.h
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_ThemeCocoa_h
+#define mozilla_widget_ThemeCocoa_h
+
+#include "Theme.h"
+
+#include "ScrollbarDrawingCocoa.h"
+
+namespace mozilla::widget {
+
+class ThemeCocoa : public Theme {
+ public:
+  explicit ThemeCocoa(UniquePtr<ScrollbarDrawing>&& aScrollbarDrawing)
+      : Theme(std::move(aScrollbarDrawing)) {}
+
+  LayoutDeviceIntSize GetMinimumWidgetSize(
+      nsPresContext* aPresContext, nsIFrame* aFrame,
+      StyleAppearance aAppearance) override;
+
+  NS_IMETHOD DrawWidgetBackground(gfxContext* aContext, nsIFrame*,
+                                  StyleAppearance, const nsRect& aRect,
+                                  const nsRect& aDirtyRect,
+                                  DrawOverflow) override;
+
+  bool CreateWebRenderCommandsForWidget(
+      wr::DisplayListBuilder& aBuilder, wr::IpcResourceUpdateQueue& aResources,
+      const layers::StackingContextHelper& aSc,
+      layers::RenderRootStateManager* aManager, nsIFrame*, StyleAppearance,
+      const nsRect& aRect) override;
+
+ protected:
+  virtual ~ThemeCocoa() = default;
+};
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/ThemeColors.cpp b/widget/ThemeColors.cpp
new file mode 100644
index 0000000000..ebbfcd88b2
--- /dev/null
+++ b/widget/ThemeColors.cpp
@@ -0,0 +1,272 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ThemeColors.h"
+
+#include "mozilla/RelativeLuminanceUtils.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "ThemeDrawing.h"
+#include "nsNativeTheme.h"
+
+using namespace mozilla::gfx;
+
+namespace mozilla::widget {
+
+struct ColorPalette {
+  ColorPalette(nscolor aAccent, nscolor aForeground);
+
+  constexpr ColorPalette(sRGBColor aAccent, sRGBColor aForeground,
+                         sRGBColor aLight, sRGBColor aDark, sRGBColor aDarker)
+      : mAccent(aAccent),
+        mForeground(aForeground),
+        mAccentLight(aLight),
+        mAccentDark(aDark),
+        mAccentDarker(aDarker) {}
+
+  constexpr static ColorPalette Default() {
+    return ColorPalette(
+        sDefaultAccent, sDefaultAccentText,
+        sRGBColor::UnusualFromARGB(0x4d008deb),  // Luminance: 25.04791%
+        sRGBColor::UnusualFromARGB(0xff0250bb),  // Luminance: 9.33808%
+        sRGBColor::UnusualFromARGB(0xff054096)   // Luminance: 5.90106%
+    );
+  }
+
+  // Ensure accent color is opaque by blending with white. This serves two
+  // purposes: On one hand, it avoids surprises if we overdraw. On the other, it
+  // makes our math below make more sense, as we want to match the browser
+  // style, which has an opaque accent color.
+  static nscolor EnsureOpaque(nscolor aAccent) {
+    if (NS_GET_A(aAccent) != 0xff) {
+      return NS_ComposeColors(NS_RGB(0xff, 0xff, 0xff), aAccent);
+    }
+    return aAccent;
+  }
+
+  static nscolor GetLight(nscolor aAccent) {
+    // The luminance from the light color divided by the one of the accent color
+    // in the default palette.
+    constexpr float kLightLuminanceScale = 25.048f / 13.693f;
+    const float lightLuminanceAdjust = ThemeColors::ScaleLuminanceBy(
+        RelativeLuminanceUtils::Compute(aAccent), kLightLuminanceScale);
+    nscolor lightColor =
+        RelativeLuminanceUtils::Adjust(aAccent, lightLuminanceAdjust);
+    return NS_RGBA(NS_GET_R(lightColor), NS_GET_G(lightColor),
+                   NS_GET_B(lightColor), 0x4d);
+  }
+
+  static nscolor GetDark(nscolor aAccent) {
+    // Same deal as above (but without the alpha).
+    constexpr float kDarkLuminanceScale = 9.338f / 13.693f;
+    const float darkLuminanceAdjust = ThemeColors::ScaleLuminanceBy(
+        RelativeLuminanceUtils::Compute(aAccent), kDarkLuminanceScale);
+    return RelativeLuminanceUtils::Adjust(aAccent, darkLuminanceAdjust);
+  }
+
+  static nscolor GetDarker(nscolor aAccent) {
+    // Same deal as above.
+    constexpr float kDarkerLuminanceScale = 5.901f / 13.693f;
+    const float darkerLuminanceAdjust = ThemeColors::ScaleLuminanceBy(
+        RelativeLuminanceUtils::Compute(aAccent), kDarkerLuminanceScale);
+    return RelativeLuminanceUtils::Adjust(aAccent, darkerLuminanceAdjust);
+  }
+
+  sRGBColor mAccent;
+  sRGBColor mForeground;
+
+  // Note that depending on the exact accent color, lighter/darker might really
+  // be inverted.
+  sRGBColor mAccentLight;
+  sRGBColor mAccentDark;
+  sRGBColor mAccentDarker;
+};
+
+static nscolor GetAccentColor(bool aBackground, ColorScheme aScheme) {
+  auto useStandins = LookAndFeel::UseStandins(
+      !StaticPrefs::widget_non_native_theme_use_theme_accent());
+  return ColorPalette::EnsureOpaque(
+      LookAndFeel::Color(aBackground ? LookAndFeel::ColorID::Accentcolor
+                                     : LookAndFeel::ColorID::Accentcolortext,
+                         aScheme, useStandins));
+}
+
+static ColorPalette sDefaultLightPalette = ColorPalette::Default();
+static ColorPalette sDefaultDarkPalette = ColorPalette::Default();
+
+ColorPalette::ColorPalette(nscolor aAccent, nscolor aForeground) {
+  mAccent = sRGBColor::FromABGR(aAccent);
+  mForeground = sRGBColor::FromABGR(aForeground);
+  mAccentLight = sRGBColor::FromABGR(GetLight(aAccent));
+  mAccentDark = sRGBColor::FromABGR(GetDark(aAccent));
+  mAccentDarker = sRGBColor::FromABGR(GetDarker(aAccent));
+}
+
+ThemeAccentColor::ThemeAccentColor(const ComputedStyle& aStyle,
+                                   ColorScheme aScheme)
+    : mDefaultPalette(aScheme == ColorScheme::Light ? &sDefaultLightPalette
+                                                    : &sDefaultDarkPalette) {
+  const auto& color = aStyle.StyleUI()->mAccentColor;
+  if (color.IsAuto()) {
+    return;
+  }
+  MOZ_ASSERT(color.IsColor());
+  nscolor accentColor =
+      ColorPalette::EnsureOpaque(color.AsColor().CalcColor(aStyle));
+  if (sRGBColor::FromABGR(accentColor) == mDefaultPalette->mAccent) {
+    return;
+  }
+  mAccentColor.emplace(accentColor);
+}
+
+sRGBColor ThemeAccentColor::Get() const {
+  if (!mAccentColor) {
+    return mDefaultPalette->mAccent;
+  }
+  return sRGBColor::FromABGR(*mAccentColor);
+}
+
+sRGBColor ThemeAccentColor::GetForeground() const {
+  if (!mAccentColor) {
+    return mDefaultPalette->mForeground;
+  }
+  return sRGBColor::FromABGR(
+      ThemeColors::ComputeCustomAccentForeground(*mAccentColor));
+}
+
+sRGBColor ThemeAccentColor::GetLight() const {
+  if (!mAccentColor) {
+    return mDefaultPalette->mAccentLight;
+  }
+  return sRGBColor::FromABGR(ColorPalette::GetLight(*mAccentColor));
+}
+
+sRGBColor ThemeAccentColor::GetDark() const {
+  if (!mAccentColor) {
+    return mDefaultPalette->mAccentDark;
+  }
+  return sRGBColor::FromABGR(ColorPalette::GetDark(*mAccentColor));
+}
+
+sRGBColor ThemeAccentColor::GetDarker() const {
+  if (!mAccentColor) {
+    return mDefaultPalette->mAccentDarker;
+  }
+  return sRGBColor::FromABGR(ColorPalette::GetDarker(*mAccentColor));
+}
+
+auto ThemeColors::ShouldBeHighContrast(const nsPresContext& aPc)
+    -> HighContrastInfo {
+  // We make sure that we're drawing backgrounds, since otherwise layout will
+  // darken our used text colors etc anyways, and that can cause contrast issues
+  // with dark high-contrast themes.
+  if (!aPc.GetBackgroundColorDraw()) {
+    return {};
+  }
+  const auto& prefs = PreferenceSheet::PrefsFor(*aPc.Document());
+  return {prefs.NonNativeThemeShouldBeHighContrast(),
+          prefs.mMustUseLightSystemColors};
+}
+
+ColorScheme ThemeColors::ColorSchemeForWidget(const nsIFrame* aFrame,
+                                              StyleAppearance aAppearance,
+                                              const HighContrastInfo& aInfo) {
+  if (aInfo.mMustUseLightSystemColors) {
+    return ColorScheme::Light;
+  }
+  if (!nsNativeTheme::IsWidgetScrollbarPart(aAppearance)) {
+    return LookAndFeel::ColorSchemeForFrame(aFrame);
+  }
+  // Scrollbars are a bit tricky. Their used color-scheme depends on whether the
+  // background they are on is light or dark.
+  //
+  // TODO(emilio): This heuristic effectively predates the color-scheme CSS
+  // property. Perhaps we should check whether the style or the document set
+  // `color-scheme` to something that isn't `normal`, and if so go through the
+  // code-path above.
+  if (StaticPrefs::widget_disable_dark_scrollbar()) {
+    return ColorScheme::Light;
+  }
+  return nsNativeTheme::IsDarkBackgroundForScrollbar(
+             const_cast<nsIFrame*>(aFrame))
+             ? ColorScheme::Dark
+             : ColorScheme::Light;
+}
+
+/*static*/
+void ThemeColors::RecomputeAccentColors() {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+
+  sDefaultLightPalette =
+      ColorPalette(GetAccentColor(true, ColorScheme::Light),
+                   GetAccentColor(false, ColorScheme::Light));
+
+  sDefaultDarkPalette = ColorPalette(GetAccentColor(true, ColorScheme::Dark),
+                                     GetAccentColor(false, ColorScheme::Dark));
+}
+
+/*static*/
+nscolor ThemeColors::ComputeCustomAccentForeground(nscolor aColor) {
+  // Contrast ratio is defined in
+  // https://www.w3.org/TR/WCAG20/#contrast-ratiodef as:
+  //
+  //   (L1 + 0.05) / (L2 + 0.05)
+  //
+  // Where L1 is the lighter color, and L2 is the darker one. So we determine
+  // whether we're dark or light and resolve the equation for the target ratio.
+  //
+  // So when lightening:
+  //
+  //   L1 = k * (L2 + 0.05) - 0.05
+  //
+  // And when darkening:
+  //
+  //   L2 = (L1 + 0.05) / k - 0.05
+  //
+  const float luminance = RelativeLuminanceUtils::Compute(aColor);
+
+  // We generally prefer white unless we can't because the color is really light
+  // and we can't provide reasonable contrast.
+  const float ratioWithWhite = 1.05f / (luminance + 0.05f);
+  const bool canBeWhite =
+      ratioWithWhite >=
+      StaticPrefs::layout_css_accent_color_min_contrast_ratio();
+  if (canBeWhite) {
+    return NS_RGB(0xff, 0xff, 0xff);
+  }
+  const float targetRatio =
+      StaticPrefs::layout_css_accent_color_darkening_target_contrast_ratio();
+  const float targetLuminance = (luminance + 0.05f) / targetRatio - 0.05f;
+  return RelativeLuminanceUtils::Adjust(aColor, targetLuminance);
+}
+
+nscolor ThemeColors::AdjustUnthemedScrollbarThumbColor(
+    nscolor aFaceColor, dom::ElementState aStates) {
+  // In Windows 10, scrollbar thumb has the following colors:
+  //
+  // State  | Color    | Luminance
+  // -------+----------+----------
+  // Normal | Gray 205 |     61.0%
+  // Hover  | Gray 166 |     38.1%
+  // Active | Gray 96  |     11.7%
+  //
+  // This function is written based on the ratios between the values.
+  bool isActive = aStates.HasState(dom::ElementState::ACTIVE);
+  bool isHover = aStates.HasState(dom::ElementState::HOVER);
+  if (!isActive && !isHover) {
+    return aFaceColor;
+  }
+  float luminance = RelativeLuminanceUtils::Compute(aFaceColor);
+  if (isActive) {
+    // 11.7 / 61.0
+    luminance = ScaleLuminanceBy(luminance, 0.192f);
+  } else {
+    // 38.1 / 61.0
+    luminance = ScaleLuminanceBy(luminance, 0.625f);
+  }
+  return RelativeLuminanceUtils::Adjust(aFaceColor, luminance);
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/ThemeColors.h b/widget/ThemeColors.h
new file mode 100644
index 0000000000..739a7ca0f0
--- /dev/null
+++ b/widget/ThemeColors.h
@@ -0,0 +1,116 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_ThemeColors_h
+#define mozilla_widget_ThemeColors_h
+
+#include "mozilla/dom/Document.h"
+#include "mozilla/gfx/Types.h"
+#include "mozilla/LookAndFeel.h"
+#include "nsIFrame.h"
+
+namespace mozilla::widget {
+
+static constexpr gfx::sRGBColor sDefaultAccent(
+    gfx::sRGBColor::UnusualFromARGB(0xff0060df));  // Luminance: 13.69346%
+static constexpr gfx::sRGBColor sDefaultAccentText(
+    gfx::sRGBColor::OpaqueWhite());
+
+struct ColorPalette;
+
+class ThemeAccentColor {
+ protected:
+  using sRGBColor = mozilla::gfx::sRGBColor;
+  using ComputedStyle = mozilla::ComputedStyle;
+
+  Maybe<nscolor> mAccentColor;
+  const ColorPalette* mDefaultPalette = nullptr;
+
+ public:
+  explicit ThemeAccentColor(const ComputedStyle&, ColorScheme);
+  virtual ~ThemeAccentColor() = default;
+
+  sRGBColor Get() const;
+  sRGBColor GetForeground() const;
+  sRGBColor GetLight() const;
+  sRGBColor GetDark() const;
+  sRGBColor GetDarker() const;
+};
+
+// Widget color information associated to a particular frame.
+class ThemeColors {
+ protected:
+  using Document = mozilla::dom::Document;
+  using sRGBColor = mozilla::gfx::sRGBColor;
+  using LookAndFeel = mozilla::LookAndFeel;
+  using StyleSystemColor = mozilla::StyleSystemColor;
+  using AccentColor = ThemeAccentColor;
+
+  struct HighContrastInfo {
+    bool mHighContrast = false;
+    bool mMustUseLightSystemColors = false;
+  };
+
+  const Document& mDoc;
+  const HighContrastInfo mHighContrastInfo;
+  const ColorScheme mColorScheme;
+  const AccentColor mAccentColor;
+
+ public:
+  explicit ThemeColors(const nsIFrame* aFrame, StyleAppearance aAppearance)
+      : mDoc(*aFrame->PresContext()->Document()),
+        mHighContrastInfo(ShouldBeHighContrast(*aFrame->PresContext())),
+        mColorScheme(ColorSchemeForWidget(aFrame, aAppearance, mHighContrastInfo)),
+        mAccentColor(*aFrame->Style(), mColorScheme) {}
+  virtual ~ThemeColors() = default;
+
+  [[nodiscard]] static float ScaleLuminanceBy(float aLuminance, float aFactor) {
+    return aLuminance >= 0.18f ? aLuminance * aFactor : aLuminance / aFactor;
+  }
+
+  const AccentColor& Accent() const { return mAccentColor; }
+  bool HighContrast() const { return mHighContrastInfo.mHighContrast; }
+  bool IsDark() const { return mColorScheme == ColorScheme::Dark; }
+
+  nscolor SystemNs(StyleSystemColor aColor) const {
+    return LookAndFeel::Color(aColor, mColorScheme,
+                              LookAndFeel::ShouldUseStandins(mDoc, aColor));
+  }
+
+  sRGBColor System(StyleSystemColor aColor) const {
+    return sRGBColor::FromABGR(SystemNs(aColor));
+  }
+
+  template <typename Compute>
+  sRGBColor SystemOrElse(StyleSystemColor aColor, Compute aCompute) const {
+    if (auto color = LookAndFeel::GetColor(
+            aColor, mColorScheme,
+            LookAndFeel::ShouldUseStandins(mDoc, aColor))) {
+      return sRGBColor::FromABGR(*color);
+    }
+    return aCompute();
+  }
+
+  std::pair<sRGBColor, sRGBColor> SystemPair(StyleSystemColor aFirst,
+                                             StyleSystemColor aSecond) const {
+    return std::make_pair(System(aFirst), System(aSecond));
+  }
+
+  // Whether we should use system colors (for high contrast mode).
+  static HighContrastInfo ShouldBeHighContrast(const nsPresContext&);
+  static ColorScheme ColorSchemeForWidget(const nsIFrame*, StyleAppearance,
+                                          const HighContrastInfo&);
+
+  static void RecomputeAccentColors();
+
+  static nscolor ComputeCustomAccentForeground(nscolor aColor);
+
+  static nscolor AdjustUnthemedScrollbarThumbColor(nscolor aFaceColor,
+                                                   dom::ElementState aStates);
+};
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/ThemeDrawing.cpp b/widget/ThemeDrawing.cpp
new file mode 100644
index 0000000000..93e317a41b
--- /dev/null
+++ b/widget/ThemeDrawing.cpp
@@ -0,0 +1,183 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ThemeDrawing.h"
+
+namespace mozilla::widget {
+
+/*static*/
+void ThemeDrawing::FillRect(DrawTarget& aDt, const LayoutDeviceRect& aRect,
+                            const sRGBColor& aColor) {
+  aDt.FillRect(aRect.ToUnknownRect(), gfx::ColorPattern(ToDeviceColor(aColor)));
+}
+
+/*static*/
+void ThemeDrawing::FillRect(WebRenderBackendData& aWrData,
+                            const LayoutDeviceRect& aRect,
+                            const sRGBColor& aColor) {
+  const bool kBackfaceIsVisible = true;
+  auto dest = wr::ToLayoutRect(aRect);
+  aWrData.mBuilder.PushRect(dest, dest, kBackfaceIsVisible, false, false,
+                            wr::ToColorF(ToDeviceColor(aColor)));
+}
+
+/*static*/
+LayoutDeviceIntCoord ThemeDrawing::SnapBorderWidth(const CSSCoord& aCssWidth,
+                                                   const DPIRatio& aDpiRatio) {
+  if (aCssWidth == 0.0f) {
+    return 0;
+  }
+  return std::max(LayoutDeviceIntCoord(1), (aCssWidth * aDpiRatio).Truncated());
+}
+
+/*static*/
+void ThemeDrawing::PaintArrow(DrawTarget& aDrawTarget,
+                              const LayoutDeviceRect& aRect,
+                              const float aArrowPolygonX[],
+                              const float aArrowPolygonY[],
+                              const float aArrowPolygonSize,
+                              const int32_t aArrowNumPoints,
+                              const sRGBColor aFillColor) {
+  const float scale = ScaleToFillRect(aRect, aArrowPolygonSize);
+
+  auto center = aRect.Center().ToUnknownPoint();
+
+  RefPtr<gfx::PathBuilder> builder = aDrawTarget.CreatePathBuilder();
+  gfx::Point p =
+      center + gfx::Point(aArrowPolygonX[0] * scale, aArrowPolygonY[0] * scale);
+  builder->MoveTo(p);
+  for (int32_t i = 1; i < aArrowNumPoints; i++) {
+    p = center +
+        gfx::Point(aArrowPolygonX[i] * scale, aArrowPolygonY[i] * scale);
+    builder->LineTo(p);
+  }
+  RefPtr<gfx::Path> path = builder->Finish();
+
+  aDrawTarget.Fill(path, gfx::ColorPattern(ToDeviceColor(aFillColor)));
+}
+
+void ThemeDrawing::PaintRoundedRectWithRadius(
+    WebRenderBackendData& aWrData, const LayoutDeviceRect& aRect,
+    const LayoutDeviceRect& aClipRect, const sRGBColor& aBackgroundColor,
+    const sRGBColor& aBorderColor, const CSSCoord& aBorderWidth,
+    const CSSCoord& aRadius, const DPIRatio& aDpiRatio) {
+  const bool kBackfaceIsVisible = true;
+  const LayoutDeviceCoord borderWidth(SnapBorderWidth(aBorderWidth, aDpiRatio));
+  const LayoutDeviceCoord radius(aRadius * aDpiRatio);
+  const wr::LayoutRect dest = wr::ToLayoutRect(aRect);
+  const wr::LayoutRect clip = wr::ToLayoutRect(aClipRect);
+
+  // Push the background.
+  if (aBackgroundColor.a != 0.0f) {
+    auto backgroundColor = wr::ToColorF(ToDeviceColor(aBackgroundColor));
+    wr::LayoutRect backgroundRect = [&] {
+      LayoutDeviceRect bg = aRect;
+      bg.Deflate(borderWidth);
+      return wr::ToLayoutRect(bg);
+    }();
+    if (radius == 0.0f) {
+      aWrData.mBuilder.PushRect(backgroundRect, clip, kBackfaceIsVisible, false,
+                                false, backgroundColor);
+    } else {
+      // NOTE(emilio): This follows DisplayListBuilder::PushRoundedRect and
+      // draws the rounded fill as an extra thick rounded border instead of a
+      // rectangle that's clipped to a rounded clip. Refer to that method for a
+      // justification. See bug 1694269.
+      LayoutDeviceCoord backgroundRadius =
+          std::max(0.0f, float(radius) - float(borderWidth));
+      wr::BorderSide side = {backgroundColor, wr::BorderStyle::Solid};
+      const wr::BorderSide sides[4] = {side, side, side, side};
+      float h = backgroundRect.width() * 0.6f;
+      float v = backgroundRect.height() * 0.6f;
+      wr::LayoutSideOffsets widths = {v, h, v, h};
+      wr::BorderRadius radii = {{backgroundRadius, backgroundRadius},
+                                {backgroundRadius, backgroundRadius},
+                                {backgroundRadius, backgroundRadius},
+                                {backgroundRadius, backgroundRadius}};
+      aWrData.mBuilder.PushBorder(backgroundRect, clip, kBackfaceIsVisible,
+                                  widths, {sides, 4}, radii);
+    }
+  }
+
+  if (borderWidth != 0.0f && aBorderColor.a != 0.0f) {
+    // Push the border.
+    const auto borderColor = ToDeviceColor(aBorderColor);
+    const auto side = wr::ToBorderSide(borderColor, StyleBorderStyle::Solid);
+    const wr::BorderSide sides[4] = {side, side, side, side};
+    const LayoutDeviceSize sideRadius(radius, radius);
+    const auto widths =
+        wr::ToBorderWidths(borderWidth, borderWidth, borderWidth, borderWidth);
+    const auto wrRadius =
+        wr::ToBorderRadius(sideRadius, sideRadius, sideRadius, sideRadius);
+    aWrData.mBuilder.PushBorder(dest, clip, kBackfaceIsVisible, widths,
+                                {sides, 4}, wrRadius);
+  }
+}
+
+void ThemeDrawing::PaintRoundedRectWithRadius(
+    DrawTarget& aDrawTarget, const LayoutDeviceRect& aRect,
+    const LayoutDeviceRect& aClipRect, const sRGBColor& aBackgroundColor,
+    const sRGBColor& aBorderColor, const CSSCoord& aBorderWidth,
+    const CSSCoord& aRadius, const DPIRatio& aDpiRatio) {
+  const LayoutDeviceCoord borderWidth(SnapBorderWidth(aBorderWidth, aDpiRatio));
+  const bool needsClip = !(aRect == aClipRect);
+  if (needsClip) {
+    aDrawTarget.PushClipRect(aClipRect.ToUnknownRect());
+  }
+
+  LayoutDeviceRect rect(aRect);
+  // Deflate the rect by half the border width, so that the middle of the
+  // stroke fills exactly the area we want to fill and not more.
+  rect.Deflate(borderWidth * 0.5f);
+
+  LayoutDeviceCoord radius(aRadius * aDpiRatio - borderWidth * 0.5f);
+  // Fix up the radius if it's too large with the rect we're going to paint.
+  {
+    LayoutDeviceCoord min = std::min(rect.width, rect.height);
+    if (radius * 2.0f > min) {
+      radius = min * 0.5f;
+    }
+  }
+
+  Maybe<gfx::ColorPattern> backgroundPattern;
+  if (aBackgroundColor.a != 0.0f) {
+    backgroundPattern.emplace(ToDeviceColor(aBackgroundColor));
+  }
+  Maybe<gfx::ColorPattern> borderPattern;
+  if (borderWidth != 0.0f && aBorderColor.a != 0.0f) {
+    borderPattern.emplace(ToDeviceColor(aBorderColor));
+  }
+
+  if (borderPattern || backgroundPattern) {
+    if (radius != 0.0f) {
+      gfx::RectCornerRadii radii(radius, radius, radius, radius);
+      RefPtr<gfx::Path> roundedRect =
+          MakePathForRoundedRect(aDrawTarget, rect.ToUnknownRect(), radii);
+
+      if (backgroundPattern) {
+        aDrawTarget.Fill(roundedRect, *backgroundPattern);
+      }
+      if (borderPattern) {
+        aDrawTarget.Stroke(roundedRect, *borderPattern,
+                           gfx::StrokeOptions(borderWidth));
+      }
+    } else {
+      if (backgroundPattern) {
+        aDrawTarget.FillRect(rect.ToUnknownRect(), *backgroundPattern);
+      }
+      if (borderPattern) {
+        aDrawTarget.StrokeRect(rect.ToUnknownRect(), *borderPattern,
+                               gfx::StrokeOptions(borderWidth));
+      }
+    }
+  }
+
+  if (needsClip) {
+    aDrawTarget.PopClip();
+  }
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/ThemeDrawing.h b/widget/ThemeDrawing.h
new file mode 100644
index 0000000000..469c29ea2f
--- /dev/null
+++ b/widget/ThemeDrawing.h
@@ -0,0 +1,79 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_ThemeDrawing_h
+#define mozilla_widget_ThemeDrawing_h
+
+#include "mozilla/layers/IpcResourceUpdateQueue.h"
+#include "mozilla/layers/RenderRootStateManager.h"
+#include "mozilla/layers/StackingContextHelper.h"
+#include "RetainedDisplayListBuilder.h"
+
+namespace mozilla::widget {
+
+struct WebRenderBackendData {
+  wr::DisplayListBuilder& mBuilder;
+  wr::IpcResourceUpdateQueue& mResources;
+  const layers::StackingContextHelper& mSc;
+  layers::RenderRootStateManager* mManager;
+};
+
+class ThemeDrawing {
+ protected:
+  using DrawTarget = gfx::DrawTarget;
+  using sRGBColor = gfx::sRGBColor;
+  using DPIRatio = CSSToLayoutDeviceScale;
+
+ public:
+  virtual ~ThemeDrawing() = 0;
+
+  static void FillRect(DrawTarget&, const LayoutDeviceRect&, const sRGBColor&);
+  static void FillRect(WebRenderBackendData&, const LayoutDeviceRect&,
+                       const sRGBColor&);
+
+  // Returns the right scale for points in a aSize x aSize sized box, centered
+  // at 0x0 to fill aRect in the smaller dimension.
+  static float ScaleToFillRect(const LayoutDeviceRect& aRect,
+                               const float& aSize) {
+    return std::min(aRect.width, aRect.height) / aSize;
+  }
+
+  static LayoutDeviceIntCoord SnapBorderWidth(const CSSCoord& aCssWidth,
+                                              const DPIRatio& aDpiRatio);
+
+  static void PaintArrow(DrawTarget&, const LayoutDeviceRect&,
+                         const float aArrowPolygonX[],
+                         const float aArrowPolygonY[],
+                         const float aArrowPolygonSize,
+                         const int32_t aArrowNumPoints,
+                         const sRGBColor aFillColor);
+
+  static void PaintRoundedRectWithRadius(
+      DrawTarget&, const LayoutDeviceRect& aRect,
+      const LayoutDeviceRect& aClipRect, const sRGBColor& aBackgroundColor,
+      const sRGBColor& aBorderColor, const CSSCoord& aBorderWidth,
+      const CSSCoord& aRadius, const DPIRatio&);
+  static void PaintRoundedRectWithRadius(
+      WebRenderBackendData&, const LayoutDeviceRect& aRect,
+      const LayoutDeviceRect& aClipRect, const sRGBColor& aBackgroundColor,
+      const sRGBColor& aBorderColor, const CSSCoord& aBorderWidth,
+      const CSSCoord& aRadius, const DPIRatio&);
+  template <typename PaintBackendData>
+  static void PaintRoundedRectWithRadius(PaintBackendData& aData,
+                                         const LayoutDeviceRect& aRect,
+                                         const sRGBColor& aBackgroundColor,
+                                         const sRGBColor& aBorderColor,
+                                         const CSSCoord& aBorderWidth,
+                                         const CSSCoord& aRadius,
+                                         const DPIRatio& aDpiRatio) {
+    PaintRoundedRectWithRadius(aData, aRect, aRect, aBackgroundColor,
+                               aBorderColor, aBorderWidth, aRadius, aDpiRatio);
+  }
+};
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/TouchEvents.h b/widget/TouchEvents.h
new file mode 100644
index 0000000000..5259276d52
--- /dev/null
+++ b/widget/TouchEvents.h
@@ -0,0 +1,220 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_TouchEvents_h__
+#define mozilla_TouchEvents_h__
+
+#include <stdint.h>
+
+#include "mozilla/dom/Touch.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/RefPtr.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+
+/******************************************************************************
+ * mozilla::WidgetGestureNotifyEvent
+ *
+ * This event is the first event generated when the user touches
+ * the screen with a finger, and it's meant to decide what kind
+ * of action we'll use for that touch interaction.
+ *
+ * The event is dispatched to the layout and based on what is underneath
+ * the initial contact point it's then decided if we should pan
+ * (finger scrolling) or drag the target element.
+ ******************************************************************************/
+
+class WidgetGestureNotifyEvent : public WidgetGUIEvent {
+ public:
+  virtual WidgetGestureNotifyEvent* AsGestureNotifyEvent() override {
+    return this;
+  }
+
+  WidgetGestureNotifyEvent(bool aIsTrusted, EventMessage aMessage,
+                           nsIWidget* aWidget,
+                           const WidgetEventTime* aTime = nullptr)
+      : WidgetGUIEvent(aIsTrusted, aMessage, aWidget, eGestureNotifyEventClass,
+                       aTime),
+        mPanDirection(ePanNone),
+        mDisplayPanFeedback(false) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    // XXX Looks like this event is handled only in PostHandleEvent() of
+    //     EventStateManager.  Therefore, it might be possible to handle this
+    //     in PreHandleEvent() and not to dispatch as a DOM event into the DOM
+    //     tree like ContentQueryEvent.  Then, this event doesn't need to
+    //     support Duplicate().
+    MOZ_ASSERT(mClass == eGestureNotifyEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetGestureNotifyEvent* result =
+        new WidgetGestureNotifyEvent(false, mMessage, nullptr, this);
+    result->AssignGestureNotifyEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  typedef int8_t PanDirectionType;
+  enum PanDirection : PanDirectionType {
+    ePanNone,
+    ePanVertical,
+    ePanHorizontal,
+    ePanBoth
+  };
+
+  PanDirection mPanDirection;
+  bool mDisplayPanFeedback;
+
+  void AssignGestureNotifyEventData(const WidgetGestureNotifyEvent& aEvent,
+                                    bool aCopyTargets) {
+    AssignGUIEventData(aEvent, aCopyTargets);
+
+    mPanDirection = aEvent.mPanDirection;
+    mDisplayPanFeedback = aEvent.mDisplayPanFeedback;
+  }
+};
+
+/******************************************************************************
+ * mozilla::WidgetSimpleGestureEvent
+ ******************************************************************************/
+
+class WidgetSimpleGestureEvent : public WidgetMouseEventBase {
+ public:
+  virtual WidgetSimpleGestureEvent* AsSimpleGestureEvent() override {
+    return this;
+  }
+
+  WidgetSimpleGestureEvent(bool aIsTrusted, EventMessage aMessage,
+                           nsIWidget* aWidget,
+                           const WidgetEventTime* aTime = nullptr)
+      : WidgetMouseEventBase(aIsTrusted, aMessage, aWidget,
+                             eSimpleGestureEventClass, aTime),
+        mAllowedDirections(0),
+        mDirection(0),
+        mClickCount(0),
+        mDelta(0.0) {}
+
+  WidgetSimpleGestureEvent(const WidgetSimpleGestureEvent& aOther)
+      : WidgetMouseEventBase(aOther.IsTrusted(), aOther.mMessage,
+                             aOther.mWidget, eSimpleGestureEventClass),
+        mAllowedDirections(aOther.mAllowedDirections),
+        mDirection(aOther.mDirection),
+        mClickCount(0),
+        mDelta(aOther.mDelta) {}
+
+  virtual WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eSimpleGestureEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetSimpleGestureEvent* result =
+        new WidgetSimpleGestureEvent(false, mMessage, nullptr, this);
+    result->AssignSimpleGestureEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  // See SimpleGestureEvent.webidl for values
+  uint32_t mAllowedDirections;
+  // See SimpleGestureEvent.webidl for values
+  uint32_t mDirection;
+  // The number of taps for tap events
+  uint32_t mClickCount;
+  // Delta for magnify and rotate events
+  double mDelta;
+
+  // XXX Not tested by test_assign_event_data.html
+  void AssignSimpleGestureEventData(const WidgetSimpleGestureEvent& aEvent,
+                                    bool aCopyTargets) {
+    AssignMouseEventBaseData(aEvent, aCopyTargets);
+
+    // mAllowedDirections isn't copied
+    mDirection = aEvent.mDirection;
+    mDelta = aEvent.mDelta;
+    mClickCount = aEvent.mClickCount;
+  }
+};
+
+/******************************************************************************
+ * mozilla::WidgetTouchEvent
+ ******************************************************************************/
+
+class WidgetTouchEvent final : public WidgetInputEvent {
+ public:
+  typedef nsTArray<RefPtr<mozilla::dom::Touch>> TouchArray;
+  typedef AutoTArray<RefPtr<mozilla::dom::Touch>, 10> AutoTouchArray;
+  typedef AutoTouchArray::base_type TouchArrayBase;
+
+  WidgetTouchEvent* AsTouchEvent() override { return this; }
+
+  MOZ_COUNTED_DEFAULT_CTOR(WidgetTouchEvent)
+
+  WidgetTouchEvent(const WidgetTouchEvent& aOther)
+      : WidgetInputEvent(aOther.IsTrusted(), aOther.mMessage, aOther.mWidget,
+                         eTouchEventClass) {
+    MOZ_COUNT_CTOR(WidgetTouchEvent);
+    mModifiers = aOther.mModifiers;
+    mTimeStamp = aOther.mTimeStamp;
+    mTouches.AppendElements(aOther.mTouches);
+    mInputSource = aOther.mInputSource;
+    mButton = aOther.mButton;
+    mButtons = aOther.mButtons;
+    mFlags.mCancelable = mMessage != eTouchCancel;
+    mFlags.mHandledByAPZ = aOther.mFlags.mHandledByAPZ;
+  }
+
+  WidgetTouchEvent(WidgetTouchEvent&& aOther)
+      : WidgetInputEvent(std::move(aOther)) {
+    MOZ_COUNT_CTOR(WidgetTouchEvent);
+    mModifiers = aOther.mModifiers;
+    mTimeStamp = aOther.mTimeStamp;
+    mTouches = std::move(aOther.mTouches);
+    mInputSource = aOther.mInputSource;
+    mButton = aOther.mButton;
+    mButtons = aOther.mButtons;
+    mFlags = aOther.mFlags;
+  }
+
+  WidgetTouchEvent& operator=(WidgetTouchEvent&&) = default;
+
+  WidgetTouchEvent(bool aIsTrusted, EventMessage aMessage, nsIWidget* aWidget,
+                   const WidgetEventTime* aTime = nullptr)
+      : WidgetInputEvent(aIsTrusted, aMessage, aWidget, eTouchEventClass,
+                         aTime) {
+    MOZ_COUNT_CTOR(WidgetTouchEvent);
+    mFlags.mCancelable = mMessage != eTouchCancel;
+  }
+
+  MOZ_COUNTED_DTOR_OVERRIDE(WidgetTouchEvent)
+
+  WidgetEvent* Duplicate() const override {
+    MOZ_ASSERT(mClass == eTouchEventClass,
+               "Duplicate() must be overridden by sub class");
+    // Not copying widget, it is a weak reference.
+    WidgetTouchEvent* result =
+        new WidgetTouchEvent(false, mMessage, nullptr, this);
+    result->AssignTouchEventData(*this, true);
+    result->mFlags = mFlags;
+    return result;
+  }
+
+  TouchArray mTouches;
+  uint16_t mInputSource = 5;  // MouseEvent_Binding::MOZ_SOURCE_TOUCH
+  int16_t mButton = eNotPressed;
+  int16_t mButtons = 0;
+
+  void AssignTouchEventData(const WidgetTouchEvent& aEvent, bool aCopyTargets) {
+    AssignInputEventData(aEvent, aCopyTargets);
+
+    // Assign*EventData() assume that they're called only new instance.
+    MOZ_ASSERT(mTouches.IsEmpty());
+    mTouches.AppendElements(aEvent.mTouches);
+    mInputSource = aEvent.mInputSource;
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_TouchEvents_h__
diff --git a/widget/TouchResampler.cpp b/widget/TouchResampler.cpp
new file mode 100644
index 0000000000..eeed30fe0e
--- /dev/null
+++ b/widget/TouchResampler.cpp
@@ -0,0 +1,377 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TouchResampler.h"
+
+#include "nsAlgorithm.h"
+
+/**
+ * TouchResampler implementation
+ */
+
+namespace mozilla {
+namespace widget {
+
+// The values below have been tested and found to be acceptable on a device
+// with a display refresh rate of 60Hz and touch sampling rate of 100Hz.
+// While their "ideal" values are dependent on the exact rates of each device,
+// the values we've picked below should be somewhat robust across a variation of
+// different rates. They mostly aim to avoid making predictions that are too far
+// away (in terms of distance) from the finger, and to detect pauses in the
+// finger motion without too much delay.
+
+// Maximum time between two consecutive data points to consider resampling
+// between them.
+// Values between 1x and 5x of the touch sampling interval are reasonable.
+static const double kTouchResampleWindowSize = 40.0;
+
+// These next two values constrain the sampling timestamp.
+// Our caller will usually adjust frame timestamps to be slightly in the past,
+// for example by 5ms. This means that, during normal operation, we will
+// maximally need to predict by [touch sampling rate] minus 5ms.
+// So we would like kTouchResampleMaxPredictMs to satisfy the following:
+// kTouchResampleMaxPredictMs + [frame time adjust] > [touch sampling rate]
+static const double kTouchResampleMaxPredictMs = 8.0;
+// This one is a protection against very outdated frame timestamps.
+// Values larger than the touch sampling interval and less than 3x of the vsync
+// interval are reasonable.
+static const double kTouchResampleMaxBacksampleMs = 20.0;
+
+// The maximum age of the most recent data point to consider resampling.
+// Should be between 1x and 3x of the touch sampling interval.
+static const double kTouchResampleOldTouchThresholdMs = 17.0;
+
+uint64_t TouchResampler::ProcessEvent(MultiTouchInput&& aInput) {
+  mCurrentTouches.UpdateFromEvent(aInput);
+
+  uint64_t eventId = mNextEventId;
+  mNextEventId++;
+
+  if (aInput.mType == MultiTouchInput::MULTITOUCH_MOVE) {
+    // Touch move events are deferred until NotifyFrame.
+    mDeferredTouchMoveEvents.push({std::move(aInput), eventId});
+  } else {
+    // Non-move events are transferred to the outgoing queue unmodified.
+    // If there are pending touch move events, flush those out first, so that
+    // events are emitted in the right order.
+    FlushDeferredTouchMoveEventsUnresampled();
+    if (mInResampledState) {
+      // Return to a non-resampled state before emitting a non-move event.
+      ReturnToNonResampledState();
+    }
+    EmitEvent(std::move(aInput), eventId);
+  }
+
+  return eventId;
+}
+
+void TouchResampler::NotifyFrame(const TimeStamp& aTimeStamp) {
+  TimeStamp lastTouchTime = mCurrentTouches.LatestDataPointTime();
+  if (mDeferredTouchMoveEvents.empty() ||
+      (lastTouchTime &&
+       lastTouchTime < aTimeStamp - TimeDuration::FromMilliseconds(
+                                        kTouchResampleOldTouchThresholdMs))) {
+    // We haven't received a touch move event in a while, so the fingers must
+    // have stopped moving. Flush any old touch move events.
+    FlushDeferredTouchMoveEventsUnresampled();
+
+    if (mInResampledState) {
+      // Make sure we pause at the resting position that we actually observed,
+      // and not at a resampled position.
+      ReturnToNonResampledState();
+    }
+
+    // Clear touch location history so that we don't resample across a pause.
+    mCurrentTouches.ClearDataPoints();
+    return;
+  }
+
+  MOZ_RELEASE_ASSERT(lastTouchTime);
+  TimeStamp lowerBound = lastTouchTime - TimeDuration::FromMilliseconds(
+                                             kTouchResampleMaxBacksampleMs);
+  TimeStamp upperBound = lastTouchTime + TimeDuration::FromMilliseconds(
+                                             kTouchResampleMaxPredictMs);
+  TimeStamp sampleTime = clamped(aTimeStamp, lowerBound, upperBound);
+
+  if (mLastEmittedEventTime && sampleTime < mLastEmittedEventTime) {
+    // Keep emitted timestamps in order.
+    sampleTime = mLastEmittedEventTime;
+  }
+
+  // We have at least one pending touch move event. Pick one of the events from
+  // mDeferredTouchMoveEvents as the base event for the resampling adjustment.
+  // We want to produce an event stream whose timestamps are in the right order.
+  // As the base event, use the first event that's at or after sampleTime,
+  // unless there is no such event, in that case use the last one we have. We
+  // will set the timestamp on the resampled event to sampleTime later.
+  // Flush out any older events so that everything remains in the right order.
+  MultiTouchInput input;
+  uint64_t eventId;
+  while (true) {
+    MOZ_RELEASE_ASSERT(!mDeferredTouchMoveEvents.empty());
+    std::tie(input, eventId) = std::move(mDeferredTouchMoveEvents.front());
+    mDeferredTouchMoveEvents.pop();
+    if (mDeferredTouchMoveEvents.empty() || input.mTimeStamp >= sampleTime) {
+      break;
+    }
+    // Flush this event to the outgoing queue without resampling. What ends up
+    // on the screen will still be smooth because we will proceed to emit a
+    // resampled event before the paint for this frame starts.
+    PrependLeftoverHistoricalData(&input);
+    MOZ_RELEASE_ASSERT(input.mTimeStamp < sampleTime);
+    EmitEvent(std::move(input), eventId);
+  }
+
+  mOriginalOfResampledTouchMove = Nothing();
+
+  // Compute the resampled touch positions.
+  nsTArray<ScreenIntPoint> resampledPositions;
+  bool anyPositionDifferentFromOriginal = false;
+  for (const auto& touch : input.mTouches) {
+    ScreenIntPoint resampledPosition =
+        mCurrentTouches.ResampleTouchPositionAtTime(
+            touch.mIdentifier, touch.mScreenPoint, sampleTime);
+    if (resampledPosition != touch.mScreenPoint) {
+      anyPositionDifferentFromOriginal = true;
+    }
+    resampledPositions.AppendElement(resampledPosition);
+  }
+
+  if (anyPositionDifferentFromOriginal) {
+    // Store a copy of the original event, so that we can return to an
+    // non-resampled position later, if necessary.
+    mOriginalOfResampledTouchMove = Some(input);
+
+    // Add the original observed position to the historical data, as well as any
+    // leftover historical positions from the previous touch move event, and
+    // store the resampled values in the "final" position of the event.
+    PrependLeftoverHistoricalData(&input);
+    for (size_t i = 0; i < input.mTouches.Length(); i++) {
+      auto& touch = input.mTouches[i];
+      touch.mHistoricalData.AppendElement(SingleTouchData::HistoricalTouchData{
+          input.mTimeStamp,
+          touch.mScreenPoint,
+          touch.mLocalScreenPoint,
+          touch.mRadius,
+          touch.mRotationAngle,
+          touch.mForce,
+      });
+
+      // Remove any historical touch data that's in the future, compared to
+      // sampleTime. This data will be included by upcoming touch move
+      // events. This only happens if the frame timestamp can be older than the
+      // event timestamp, i.e. if interpolation occurs (rather than
+      // extrapolation).
+      auto futureDataStart = std::find_if(
+          touch.mHistoricalData.begin(), touch.mHistoricalData.end(),
+          [sampleTime](
+              const SingleTouchData::HistoricalTouchData& aHistoricalData) {
+            return aHistoricalData.mTimeStamp > sampleTime;
+          });
+      if (futureDataStart != touch.mHistoricalData.end()) {
+        nsTArray<SingleTouchData::HistoricalTouchData> futureData(
+            Span<SingleTouchData::HistoricalTouchData>(touch.mHistoricalData)
+                .From(futureDataStart.GetIndex()));
+        touch.mHistoricalData.TruncateLength(futureDataStart.GetIndex());
+        mRemainingTouchData.insert({touch.mIdentifier, std::move(futureData)});
+      }
+
+      touch.mScreenPoint = resampledPositions[i];
+    }
+    input.mTimeStamp = sampleTime;
+  }
+
+  EmitEvent(std::move(input), eventId);
+  mInResampledState = anyPositionDifferentFromOriginal;
+}
+
+void TouchResampler::PrependLeftoverHistoricalData(MultiTouchInput* aInput) {
+  for (auto& touch : aInput->mTouches) {
+    auto leftoverData = mRemainingTouchData.find(touch.mIdentifier);
+    if (leftoverData != mRemainingTouchData.end()) {
+      nsTArray<SingleTouchData::HistoricalTouchData> data =
+          std::move(leftoverData->second);
+      mRemainingTouchData.erase(leftoverData);
+      touch.mHistoricalData.InsertElementsAt(0, data);
+    }
+
+    if (TimeStamp cutoffTime = mLastEmittedEventTime) {
+      // If we received historical touch data that was further in the past than
+      // the last resampled event, discard that data so that the touch data
+      // points are emitted in order.
+      touch.mHistoricalData.RemoveElementsBy(
+          [cutoffTime](const SingleTouchData::HistoricalTouchData& aTouchData) {
+            return aTouchData.mTimeStamp < cutoffTime;
+          });
+    }
+  }
+  mRemainingTouchData.clear();
+}
+
+void TouchResampler::FlushDeferredTouchMoveEventsUnresampled() {
+  while (!mDeferredTouchMoveEvents.empty()) {
+    auto [input, eventId] = std::move(mDeferredTouchMoveEvents.front());
+    mDeferredTouchMoveEvents.pop();
+    PrependLeftoverHistoricalData(&input);
+    EmitEvent(std::move(input), eventId);
+    mInResampledState = false;
+    mOriginalOfResampledTouchMove = Nothing();
+  }
+}
+
+void TouchResampler::ReturnToNonResampledState() {
+  MOZ_RELEASE_ASSERT(mInResampledState);
+  MOZ_RELEASE_ASSERT(mDeferredTouchMoveEvents.empty(),
+                     "Don't call this if there is a deferred touch move event. "
+                     "We can return to the non-resampled state by sending that "
+                     "event, rather than a copy of a previous event.");
+
+  // The last outgoing event was a resampled touch move event.
+  // Return to the non-resampled state, by sending a touch move event to
+  // "overwrite" any resampled positions with the original observed positions.
+  MultiTouchInput input = std::move(*mOriginalOfResampledTouchMove);
+  mOriginalOfResampledTouchMove = Nothing();
+
+  // For the event's timestamp, we want to backdate the correction as far as we
+  // can, while still preserving timestamp ordering. But we also don't want to
+  // backdate it to be older than it was originally.
+  if (mLastEmittedEventTime > input.mTimeStamp) {
+    input.mTimeStamp = mLastEmittedEventTime;
+  }
+
+  // Assemble the correct historical touch data for this event.
+  // We don't want to include data points that we've already sent out with the
+  // resampled event. And from the leftover data points, we only want those that
+  // don't duplicate the final time + position of this event.
+  for (auto& touch : input.mTouches) {
+    touch.mHistoricalData.Clear();
+  }
+  PrependLeftoverHistoricalData(&input);
+  for (auto& touch : input.mTouches) {
+    touch.mHistoricalData.RemoveElementsBy([&](const auto& histData) {
+      return histData.mTimeStamp >= input.mTimeStamp;
+    });
+  }
+
+  EmitExtraEvent(std::move(input));
+  mInResampledState = false;
+}
+
+void TouchResampler::TouchInfo::Update(const SingleTouchData& aTouch,
+                                       const TimeStamp& aEventTime) {
+  for (const auto& historicalData : aTouch.mHistoricalData) {
+    mBaseDataPoint = mLatestDataPoint;
+    mLatestDataPoint =
+        Some(DataPoint{historicalData.mTimeStamp, historicalData.mScreenPoint});
+  }
+  mBaseDataPoint = mLatestDataPoint;
+  mLatestDataPoint = Some(DataPoint{aEventTime, aTouch.mScreenPoint});
+}
+
+ScreenIntPoint TouchResampler::TouchInfo::ResampleAtTime(
+    const ScreenIntPoint& aLastObservedPosition, const TimeStamp& aTimeStamp) {
+  TimeStamp cutoff =
+      aTimeStamp - TimeDuration::FromMilliseconds(kTouchResampleWindowSize);
+  if (!mBaseDataPoint || !mLatestDataPoint ||
+      !(mBaseDataPoint->mTimeStamp < mLatestDataPoint->mTimeStamp) ||
+      mBaseDataPoint->mTimeStamp < cutoff) {
+    return aLastObservedPosition;
+  }
+
+  // For the actual resampling, connect the last two data points with a line and
+  // sample along that line.
+  TimeStamp t1 = mBaseDataPoint->mTimeStamp;
+  TimeStamp t2 = mLatestDataPoint->mTimeStamp;
+  double t = (aTimeStamp - t1) / (t2 - t1);
+
+  double x1 = mBaseDataPoint->mPosition.x;
+  double x2 = mLatestDataPoint->mPosition.x;
+  double y1 = mBaseDataPoint->mPosition.y;
+  double y2 = mLatestDataPoint->mPosition.y;
+
+  int32_t resampledX = round(x1 + t * (x2 - x1));
+  int32_t resampledY = round(y1 + t * (y2 - y1));
+  return ScreenIntPoint(resampledX, resampledY);
+}
+
+void TouchResampler::CurrentTouches::UpdateFromEvent(
+    const MultiTouchInput& aInput) {
+  switch (aInput.mType) {
+    case MultiTouchInput::MULTITOUCH_START: {
+      // A new touch has been added; make sure mTouches reflects the current
+      // touches in the event.
+      nsTArray<TouchInfo> newTouches;
+      for (const auto& touch : aInput.mTouches) {
+        const auto touchInfo = TouchByIdentifier(touch.mIdentifier);
+        if (touchInfo != mTouches.end()) {
+          // This is one of the existing touches.
+          newTouches.AppendElement(std::move(*touchInfo));
+          mTouches.RemoveElementAt(touchInfo);
+        } else {
+          // This is the new touch.
+          newTouches.AppendElement(TouchInfo{
+              touch.mIdentifier, Nothing(),
+              Some(DataPoint{aInput.mTimeStamp, touch.mScreenPoint})});
+        }
+      }
+      MOZ_ASSERT(mTouches.IsEmpty(), "Missing touch end before touch start?");
+      mTouches = std::move(newTouches);
+      break;
+    }
+
+    case MultiTouchInput::MULTITOUCH_MOVE: {
+      // The touches have moved.
+      // Add position information to the history data points.
+      for (const auto& touch : aInput.mTouches) {
+        const auto touchInfo = TouchByIdentifier(touch.mIdentifier);
+        MOZ_ASSERT(touchInfo != mTouches.end());
+        if (touchInfo != mTouches.end()) {
+          touchInfo->Update(touch, aInput.mTimeStamp);
+        }
+      }
+      mLatestDataPointTime = aInput.mTimeStamp;
+      break;
+    }
+
+    case MultiTouchInput::MULTITOUCH_END: {
+      // A touch has been removed.
+      MOZ_RELEASE_ASSERT(aInput.mTouches.Length() == 1);
+      const auto touchInfo = TouchByIdentifier(aInput.mTouches[0].mIdentifier);
+      MOZ_ASSERT(touchInfo != mTouches.end());
+      if (touchInfo != mTouches.end()) {
+        mTouches.RemoveElementAt(touchInfo);
+      }
+      break;
+    }
+
+    case MultiTouchInput::MULTITOUCH_CANCEL:
+      // All touches are canceled.
+      mTouches.Clear();
+      break;
+  }
+}
+
+nsTArray<TouchResampler::TouchInfo>::iterator
+TouchResampler::CurrentTouches::TouchByIdentifier(int32_t aIdentifier) {
+  return std::find_if(mTouches.begin(), mTouches.end(),
+                      [aIdentifier](const TouchInfo& info) {
+                        return info.mIdentifier == aIdentifier;
+                      });
+}
+
+ScreenIntPoint TouchResampler::CurrentTouches::ResampleTouchPositionAtTime(
+    int32_t aIdentifier, const ScreenIntPoint& aLastObservedPosition,
+    const TimeStamp& aTimeStamp) {
+  const auto touchInfo = TouchByIdentifier(aIdentifier);
+  MOZ_ASSERT(touchInfo != mTouches.end());
+  if (touchInfo != mTouches.end()) {
+    return touchInfo->ResampleAtTime(aLastObservedPosition, aTimeStamp);
+  }
+  return aLastObservedPosition;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/TouchResampler.h b/widget/TouchResampler.h
new file mode 100644
index 0000000000..69f544b557
--- /dev/null
+++ b/widget/TouchResampler.h
@@ -0,0 +1,191 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_TouchResampler_h
+#define mozilla_widget_TouchResampler_h
+
+#include <queue>
+#include <unordered_map>
+
+#include "mozilla/Maybe.h"
+#include "mozilla/TimeStamp.h"
+#include "InputData.h"
+
+namespace mozilla {
+namespace widget {
+
+/**
+ * De-jitters touch motions by resampling (interpolating or extrapolating) touch
+ * positions for the vsync timestamp.
+ *
+ * Touch resampling improves the touch panning experience on devices where touch
+ * positions are sampled at a rate that's not an integer multiple of the display
+ * refresh rate, for example 100Hz touch sampling on a 60Hz display: Without
+ * resampling, we would alternate between taking one touch sample or two touch
+ * samples into account each frame, creating a jittery motion ("small step, big
+ * step, small step, big step").
+ * Intended for use on Android, where both touch events and vsync notifications
+ * arrive on the same thread, the Java UI thread.
+ * This class is not thread safe.
+ *
+ * TouchResampler operates in the following way:
+ *
+ * Original events are fed into ProcessEvent().
+ * Outgoing events (potentially resampled for resampling) are added to a queue
+ * and can be consumed by calling ConsumeOutgoingEvents(). Touch events which
+ * are not touch move events are forwarded instantly and not resampled. Only
+ * touch move events are resampled. Whenever a touch move event is received, it
+ * gets delayed until NotifyFrame() is called, at which point it is resampled
+ * into a resampled version for the given frame timestamp, and added to the
+ * outgoing queue. If no touch move event is received between two consecutive
+ * frames, this is treated as a stop in the touch motion. If the last outgoing
+ * event was an resampled touch move event, we return back to the non-resampled
+ * state by emitting a copy of the last original touch move event, which has
+ * unmodified position data. Touch events which are not touch move events also
+ * force a return to the non-resampled state before they are moved to the
+ * outgoing queue.
+ */
+class TouchResampler final {
+ public:
+  // Feed a touch event into the interpolater. Returns an ID that can be used to
+  // match outgoing events to this incoming event, to track data associated with
+  // this event.
+  uint64_t ProcessEvent(MultiTouchInput&& aInput);
+
+  // Emit events, potentially resampled, for this timestamp. The events are put
+  // into the outgoing queue. May not emit any events if there's no update.
+  void NotifyFrame(const TimeStamp& aTimeStamp);
+
+  // Returns true between the start and the end of a touch gesture. During this
+  // time, the caller should keep itself registered with the system frame
+  // callback mechanism, so that NotifyFrame() can be called on every frame.
+  // (Otherwise, if we only registered the callback after receiving a touch move
+  // event, the frame callback might be delayed by a full frame.)
+  bool InTouchingState() const { return mCurrentTouches.HasTouch(); }
+
+  struct OutgoingEvent {
+    // The event, potentially modified from the original for resampling.
+    MultiTouchInput mEvent;
+
+    // Some(eventId) if this event is a modified version of an original event,
+    // Nothing() if this is an extra event.
+    Maybe<uint64_t> mEventId;
+  };
+
+  // Returns the outgoing events that were produced since the last call.
+  // No event IDs will be skipped. Returns at least one outgoing event for each
+  // incoming event (possibly after a delay), and potential extra events with
+  // no originating event ID.
+  // Outgoing events should be consumed after every call to ProcessEvent() and
+  // after every call to NotifyFrame().
+  std::queue<OutgoingEvent> ConsumeOutgoingEvents() {
+    return std::move(mOutgoingEvents);
+  }
+
+ private:
+  // Add the event to the outgoing queue.
+  void EmitEvent(MultiTouchInput&& aInput, uint64_t aEventId) {
+    mLastEmittedEventTime = aInput.mTimeStamp;
+    mOutgoingEvents.push(OutgoingEvent{std::move(aInput), Some(aEventId)});
+  }
+
+  // Emit an event that does not correspond to an incoming event.
+  void EmitExtraEvent(MultiTouchInput&& aInput) {
+    mLastEmittedEventTime = aInput.mTimeStamp;
+    mOutgoingEvents.push(OutgoingEvent{std::move(aInput), Nothing()});
+  }
+
+  // Move any touch move events that we deferred for resampling to the outgoing
+  // queue unmodified, leaving mDeferredTouchMoveEvents empty.
+  void FlushDeferredTouchMoveEventsUnresampled();
+
+  // Must only be called if mInResampledState is true and
+  // mDeferredTouchMoveEvents is empty. Emits mOriginalOfResampledTouchMove,
+  // with a potentially adjusted timestamp for correct ordering.
+  void ReturnToNonResampledState();
+
+  // Takes historical touch data from mRemainingTouchData and prepends it to the
+  // data in aInput.
+  void PrependLeftoverHistoricalData(MultiTouchInput* aInput);
+
+  struct DataPoint {
+    TimeStamp mTimeStamp;
+    ScreenIntPoint mPosition;
+  };
+
+  struct TouchInfo {
+    void Update(const SingleTouchData& aTouch, const TimeStamp& aEventTime);
+    ScreenIntPoint ResampleAtTime(const ScreenIntPoint& aLastObservedPosition,
+                                  const TimeStamp& aTimeStamp);
+
+    int32_t mIdentifier = 0;
+    Maybe<DataPoint> mBaseDataPoint;
+    Maybe<DataPoint> mLatestDataPoint;
+  };
+
+  struct CurrentTouches {
+    void UpdateFromEvent(const MultiTouchInput& aInput);
+    bool HasTouch() const { return !mTouches.IsEmpty(); }
+    TimeStamp LatestDataPointTime() { return mLatestDataPointTime; }
+
+    ScreenIntPoint ResampleTouchPositionAtTime(
+        int32_t aIdentifier, const ScreenIntPoint& aLastObservedPosition,
+        const TimeStamp& aTimeStamp);
+
+    void ClearDataPoints() {
+      for (auto& touch : mTouches) {
+        touch.mBaseDataPoint = Nothing();
+        touch.mLatestDataPoint = Nothing();
+      }
+    }
+
+   private:
+    nsTArray<TouchInfo>::iterator TouchByIdentifier(int32_t aIdentifier);
+
+    nsTArray<TouchInfo> mTouches;
+    TimeStamp mLatestDataPointTime;
+  };
+
+  // The current touch positions with historical data points. This data only
+  // contains original non-resampled positions from the incoming touch events.
+  CurrentTouches mCurrentTouches;
+
+  // Incoming touch move events are stored here until NotifyFrame is called.
+  std::queue<std::pair<MultiTouchInput, uint64_t>> mDeferredTouchMoveEvents;
+
+  // Stores any touch samples that were not included in the last emitted touch
+  // move event because they were in the future compared to the emitted event's
+  // timestamp. These data points should be prepended to the historical data of
+  // the next emitted touch move evnt.
+  // Can only be non-empty if mInResampledState is true.
+  std::unordered_map<int32_t, nsTArray<SingleTouchData::HistoricalTouchData>>
+      mRemainingTouchData;
+
+  // If we're in an resampled state, because the last outgoing event was a
+  // resampled touch move event, then this contains a copy of the unresampled,
+  // original touch move event.
+  // Some() iff mInResampledState is true.
+  Maybe<MultiTouchInput> mOriginalOfResampledTouchMove;
+
+  // The stream of outgoing events that can be consumed by our caller.
+  std::queue<OutgoingEvent> mOutgoingEvents;
+
+  // The timestamp of the event that was emitted most recently, or the null
+  // timestamp if no event has been emitted yet.
+  TimeStamp mLastEmittedEventTime;
+
+  uint64_t mNextEventId = 0;
+
+  // True if the last outgoing event was a touch move event with an resampled
+  // position. We only want to stay in this state as long as a continuous stream
+  // of touch move events is coming in.
+  bool mInResampledState = false;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_TouchResampler_h
diff --git a/widget/VsyncDispatcher.cpp b/widget/VsyncDispatcher.cpp
new file mode 100644
index 0000000000..acb00a368a
--- /dev/null
+++ b/widget/VsyncDispatcher.cpp
@@ -0,0 +1,261 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MainThreadUtils.h"
+#include "VsyncDispatcher.h"
+#include "VsyncSource.h"
+#include "gfxPlatform.h"
+#include "mozilla/layers/Compositor.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+#include "mozilla/layers/CompositorThread.h"
+#include "mozilla/StaticPrefs_gfx.h"
+
+using namespace mozilla::layers;
+
+namespace mozilla {
+
+CompositorVsyncDispatcher::CompositorVsyncDispatcher(
+    RefPtr<VsyncDispatcher> aVsyncDispatcher)
+    : mVsyncDispatcher(std::move(aVsyncDispatcher)),
+      mCompositorObserverLock("CompositorObserverLock"),
+      mDidShutdown(false) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(NS_IsMainThread());
+}
+
+CompositorVsyncDispatcher::~CompositorVsyncDispatcher() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+}
+
+void CompositorVsyncDispatcher::NotifyVsync(const VsyncEvent& aVsync) {
+  // In vsync thread
+  layers::CompositorBridgeParent::PostInsertVsyncProfilerMarker(aVsync.mTime);
+
+  MutexAutoLock lock(mCompositorObserverLock);
+  if (mCompositorVsyncObserver) {
+    mCompositorVsyncObserver->NotifyVsync(aVsync);
+  }
+}
+
+void CompositorVsyncDispatcher::ObserveVsync(bool aEnable) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(XRE_IsParentProcess());
+  if (mDidShutdown) {
+    return;
+  }
+
+  if (aEnable) {
+    mVsyncDispatcher->AddVsyncObserver(this);
+  } else {
+    mVsyncDispatcher->RemoveVsyncObserver(this);
+  }
+}
+
+void CompositorVsyncDispatcher::SetCompositorVsyncObserver(
+    VsyncObserver* aVsyncObserver) {
+  // When remote compositing or running gtests, vsync observation is
+  // initiated on the main thread. Otherwise, it is initiated from the
+  // compositor thread.
+  MOZ_ASSERT(NS_IsMainThread() ||
+             CompositorThreadHolder::IsInCompositorThread());
+
+  {  // scope lock
+    MutexAutoLock lock(mCompositorObserverLock);
+    mCompositorVsyncObserver = aVsyncObserver;
+  }
+
+  bool observeVsync = aVsyncObserver != nullptr;
+  nsCOMPtr<nsIRunnable> vsyncControl = NewRunnableMethod<bool>(
+      "CompositorVsyncDispatcher::ObserveVsync", this,
+      &CompositorVsyncDispatcher::ObserveVsync, observeVsync);
+  NS_DispatchToMainThread(vsyncControl);
+}
+
+void CompositorVsyncDispatcher::Shutdown() {
+  // Need to explicitly remove CompositorVsyncDispatcher when the nsBaseWidget
+  // shuts down. Otherwise, we would get dead vsync notifications between when
+  // the nsBaseWidget shuts down and the CompositorBridgeParent shuts down.
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(!mDidShutdown);
+  ObserveVsync(false);
+  mDidShutdown = true;
+  {  // scope lock
+    MutexAutoLock lock(mCompositorObserverLock);
+    mCompositorVsyncObserver = nullptr;
+  }
+  mVsyncDispatcher = nullptr;
+}
+
+VsyncDispatcher::VsyncDispatcher(gfx::VsyncSource* aVsyncSource)
+    : mState(State(aVsyncSource), "VsyncDispatcher::mState") {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(NS_IsMainThread());
+}
+
+VsyncDispatcher::~VsyncDispatcher() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(NS_IsMainThread());
+}
+
+void VsyncDispatcher::SetVsyncSource(gfx::VsyncSource* aVsyncSource) {
+  MOZ_RELEASE_ASSERT(aVsyncSource);
+
+  auto state = mState.Lock();
+  if (aVsyncSource == state->mCurrentVsyncSource) {
+    return;
+  }
+
+  if (state->mIsObservingVsync) {
+    state->mCurrentVsyncSource->RemoveVsyncDispatcher(this);
+    aVsyncSource->AddVsyncDispatcher(this);
+  }
+  state->mCurrentVsyncSource = aVsyncSource;
+}
+
+RefPtr<gfx::VsyncSource> VsyncDispatcher::GetCurrentVsyncSource() {
+  auto state = mState.Lock();
+  return state->mCurrentVsyncSource;
+}
+
+TimeDuration VsyncDispatcher::GetVsyncRate() {
+  auto state = mState.Lock();
+  return state->mCurrentVsyncSource->GetVsyncRate();
+}
+
+static int32_t ComputeFrameRateDivisor(gfx::VsyncSource* aCurrentVsyncSource) {
+  int32_t maxRate = StaticPrefs::gfx_display_max_frame_rate();
+  if (maxRate == 0) {
+    return StaticPrefs::gfx_display_frame_rate_divisor();
+  }
+
+  // Compute the frame rate divisor based on max frame rates.
+  double frameDuration = aCurrentVsyncSource->GetVsyncRate().ToMilliseconds();
+
+  // Respect the pref gfx.display.frame-rate-divisor if larger.
+  return std::max(StaticPrefs::gfx_display_frame_rate_divisor(),
+                  int32_t(floor(1000.0 / frameDuration / maxRate)));
+}
+
+void VsyncDispatcher::NotifyVsync(const VsyncEvent& aVsync) {
+  nsTArray<RefPtr<VsyncObserver>> observers;
+  bool shouldDispatchToMainThread = false;
+  {
+    auto state = mState.Lock();
+    if (++state->mVsyncSkipCounter <
+        ComputeFrameRateDivisor(state->mCurrentVsyncSource)) {
+      return;
+    }
+    state->mVsyncSkipCounter = 0;
+
+    // Copy out the observers so that we don't keep the mutex
+    // locked while notifying vsync.
+    observers = state->mObservers.Clone();
+    shouldDispatchToMainThread = !state->mMainThreadObservers.IsEmpty() &&
+                                 (state->mLastVsyncIdSentToMainThread ==
+                                  state->mLastMainThreadProcessedVsyncId);
+  }
+
+  for (const auto& observer : observers) {
+    observer->NotifyVsync(aVsync);
+  }
+
+  if (shouldDispatchToMainThread) {
+    auto state = mState.Lock();
+    state->mLastVsyncIdSentToMainThread = aVsync.mId;
+    NS_DispatchToMainThread(NewRunnableMethod<VsyncEvent>(
+        "VsyncDispatcher::NotifyMainThreadObservers", this,
+        &VsyncDispatcher::NotifyMainThreadObservers, aVsync));
+  }
+}
+
+void VsyncDispatcher::NotifyMainThreadObservers(VsyncEvent aEvent) {
+  MOZ_ASSERT(NS_IsMainThread());
+  nsTArray<RefPtr<VsyncObserver>> observers;
+  {
+    // Copy out the main thread observers so that we don't keep the mutex
+    // locked while notifying vsync.
+    auto state = mState.Lock();
+    observers.AppendElements(state->mMainThreadObservers);
+  }
+
+  for (const auto& observer : observers) {
+    observer->NotifyVsync(aEvent);
+  }
+
+  {  // Scope lock
+    auto state = mState.Lock();
+    state->mLastMainThreadProcessedVsyncId = aEvent.mId;
+  }
+}
+
+void VsyncDispatcher::AddVsyncObserver(VsyncObserver* aVsyncObserver) {
+  MOZ_ASSERT(aVsyncObserver);
+  {  // scope lock - called on PBackground thread or main thread
+    auto state = mState.Lock();
+    if (!state->mObservers.Contains(aVsyncObserver)) {
+      state->mObservers.AppendElement(aVsyncObserver);
+    }
+  }
+
+  UpdateVsyncStatus();
+}
+
+void VsyncDispatcher::RemoveVsyncObserver(VsyncObserver* aVsyncObserver) {
+  MOZ_ASSERT(aVsyncObserver);
+  {  // scope lock - called on PBackground thread or main thread
+    auto state = mState.Lock();
+    state->mObservers.RemoveElement(aVsyncObserver);
+  }
+
+  UpdateVsyncStatus();
+}
+
+void VsyncDispatcher::AddMainThreadObserver(VsyncObserver* aObserver) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aObserver);
+  {
+    auto state = mState.Lock();
+    state->mMainThreadObservers.AppendElement(aObserver);
+  }
+
+  UpdateVsyncStatus();
+}
+
+void VsyncDispatcher::RemoveMainThreadObserver(VsyncObserver* aObserver) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aObserver);
+  {
+    auto state = mState.Lock();
+    state->mMainThreadObservers.RemoveElement(aObserver);
+  }
+
+  UpdateVsyncStatus();
+}
+
+void VsyncDispatcher::UpdateVsyncStatus() {
+  bool wasObservingVsync = false;
+  bool needVsync = false;
+  RefPtr<gfx::VsyncSource> vsyncSource;
+
+  {
+    auto state = mState.Lock();
+    wasObservingVsync = state->mIsObservingVsync;
+    needVsync =
+        !state->mObservers.IsEmpty() || !state->mMainThreadObservers.IsEmpty();
+    state->mIsObservingVsync = needVsync;
+    vsyncSource = state->mCurrentVsyncSource;
+  }
+
+  // Call Add/RemoveVsyncDispatcher outside the lock, because it can re-enter
+  // into VsyncDispatcher::NotifyVsync.
+  if (needVsync && !wasObservingVsync) {
+    vsyncSource->AddVsyncDispatcher(this);
+  } else if (!needVsync && wasObservingVsync) {
+    vsyncSource->RemoveVsyncDispatcher(this);
+  }
+}
+
+}  // namespace mozilla
diff --git a/widget/VsyncDispatcher.h b/widget/VsyncDispatcher.h
new file mode 100644
index 0000000000..1001a74888
--- /dev/null
+++ b/widget/VsyncDispatcher.h
@@ -0,0 +1,157 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_VsyncDispatcher_h
+#define mozilla_widget_VsyncDispatcher_h
+
+#include "mozilla/DataMutex.h"
+#include "mozilla/TimeStamp.h"
+#include "nsISupportsImpl.h"
+#include "nsTArray.h"
+#include "mozilla/RefPtr.h"
+#include "VsyncSource.h"
+
+namespace mozilla {
+
+class VsyncObserver {
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+
+ public:
+  // The method is called when a vsync occurs.
+  // In general, this vsync notification will occur on the hardware vsync
+  // thread from VsyncSource. But it might also be called on PVsync ipc thread
+  // if this notification is cross process. Thus all observer should check the
+  // thread model before handling the real task.
+  virtual void NotifyVsync(const VsyncEvent& aVsync) = 0;
+
+ protected:
+  VsyncObserver() = default;
+  virtual ~VsyncObserver() = default;
+};  // VsyncObserver
+
+class VsyncDispatcher;
+
+// Used to dispatch vsync events in the parent process to compositors.
+//
+// When the compositor is in-process, CompositorWidgets own a
+// CompositorVsyncDispatcher, and directly attach the compositor's observer
+// to it.
+//
+// When the compositor is out-of-process, the CompositorWidgetDelegate owns
+// the vsync dispatcher instead. The widget receives vsync observer/unobserve
+// commands via IPDL, and uses this to attach a CompositorWidgetVsyncObserver.
+// This observer forwards vsync notifications (on the vsync thread) to a
+// dedicated vsync I/O thread, which then forwards the notification to the
+// compositor thread in the compositor process.
+class CompositorVsyncDispatcher final : public VsyncObserver {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CompositorVsyncDispatcher, override)
+
+ public:
+  explicit CompositorVsyncDispatcher(RefPtr<VsyncDispatcher> aVsyncDispatcher);
+
+  // Called on the vsync thread when a hardware vsync occurs
+  void NotifyVsync(const VsyncEvent& aVsync) override;
+
+  // Compositor vsync observers must be added/removed on the compositor thread
+  void SetCompositorVsyncObserver(VsyncObserver* aVsyncObserver);
+  void Shutdown();
+
+ private:
+  virtual ~CompositorVsyncDispatcher();
+  void ObserveVsync(bool aEnable);
+
+  RefPtr<VsyncDispatcher> mVsyncDispatcher;
+  Mutex mCompositorObserverLock MOZ_UNANNOTATED;
+  RefPtr<VsyncObserver> mCompositorVsyncObserver;
+  bool mDidShutdown;
+};
+
+// Dispatch vsync events to various observers. This is used by:
+//  - CompositorVsyncDispatcher
+//  - Parent process refresh driver timers
+//  - IPC for content process refresh driver timers (VsyncParent <->
+//  VsyncMainChild)
+//  - IPC for content process worker requestAnimationFrame (VsyncParent <->
+//  VsyncWorkerChild)
+//
+// This class is only used in the parent process.
+// There is one global vsync dispatcher which is managed by gfxPlatform.
+// On Linux Wayland, there is also one vsync source and vsync dispatcher per
+// widget.
+// A vsync dispatcher can swap out its underlying VsyncSource. This happens, for
+// example, when the layout.frame_rate pref is modified, causing us to switch
+// between hardware vsync and software vsync.
+class VsyncDispatcher final {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VsyncDispatcher)
+
+ public:
+  explicit VsyncDispatcher(gfx::VsyncSource* aVsyncSource);
+
+  // Please check CompositorVsyncDispatcher::NotifyVsync().
+  void NotifyVsync(const VsyncEvent& aVsync);
+
+  // Swap out the underlying vsync source. Can be called on any thread.
+  // aVsyncSource must be non-null.
+  void SetVsyncSource(gfx::VsyncSource* aVsyncSource);
+
+  // Always non-null.
+  RefPtr<gfx::VsyncSource> GetCurrentVsyncSource();
+
+  TimeDuration GetVsyncRate();
+
+  // Add a vsync observer to this dispatcher. This is a no-op if the observer is
+  // already registered. Can be called from any thread.
+  void AddVsyncObserver(VsyncObserver* aVsyncObserver);
+
+  // Remove a vsync observer from this dispatcher. This is a no-op if the
+  // observer is not registered. Can be called from any thread.
+  void RemoveVsyncObserver(VsyncObserver* aVsyncObserver);
+
+  // Add and remove an observer for vsync which can only be notified on the
+  // main thread. Note that keeping an observer registered means vsync will keep
+  // firing, which may impact power usage. So this is intended only for "short
+  // term" vsync observers.
+  // These methods must be called on the parent process main thread, and the
+  // observer will likewise be notified on the parent process main thread.
+  void AddMainThreadObserver(VsyncObserver* aObserver);
+  void RemoveMainThreadObserver(VsyncObserver* aObserver);
+
+ private:
+  virtual ~VsyncDispatcher();
+
+  // Can be called on any thread.
+  void UpdateVsyncStatus();
+
+  // Can only be called on the main thread.
+  void NotifyMainThreadObservers(VsyncEvent aEvent);
+
+  struct State {
+    explicit State(gfx::VsyncSource* aVsyncSource)
+        : mCurrentVsyncSource(aVsyncSource) {}
+    State(State&&) = default;
+    ~State() = default;
+
+    nsTArray<RefPtr<VsyncObserver>> mObservers;
+    nsTArray<RefPtr<VsyncObserver>> mMainThreadObservers;
+    VsyncId mLastVsyncIdSentToMainThread;
+    VsyncId mLastMainThreadProcessedVsyncId;
+
+    // Always non-null.
+    RefPtr<gfx::VsyncSource> mCurrentVsyncSource;
+
+    // The number of skipped vsyncs since the last non-skipped vsync.
+    // Reset to zero every n vsyncs, where n is given by the pref
+    // gfx.display.frame-rate-divisor.
+    int32_t mVsyncSkipCounter = 0;
+
+    bool mIsObservingVsync = false;
+  };
+
+  DataMutex<State> mState;
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_widget_VsyncDispatcher_h
diff --git a/widget/WidgetEventImpl.cpp b/widget/WidgetEventImpl.cpp
new file mode 100644
index 0000000000..121b006f8a
--- /dev/null
+++ b/widget/WidgetEventImpl.cpp
@@ -0,0 +1,1970 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "BasicEvents.h"
+#include "ContentEvents.h"
+#include "MiscEvents.h"
+#include "MouseEvents.h"
+#include "NativeKeyBindingsType.h"
+#include "TextEventDispatcher.h"
+#include "TextEvents.h"
+#include "TouchEvents.h"
+
+#include "mozilla/EventStateManager.h"
+#include "mozilla/InternalMutationEvent.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_mousewheel.h"
+#include "mozilla/StaticPrefs_ui.h"
+#include "mozilla/WritingModes.h"
+#include "mozilla/dom/KeyboardEventBinding.h"
+#include "mozilla/dom/MouseEventBinding.h"
+#include "mozilla/dom/WheelEventBinding.h"
+#include "nsCommandParams.h"
+#include "nsContentUtils.h"
+#include "nsIContent.h"
+#include "nsIDragSession.h"
+#include "nsPrintfCString.h"
+
+#if defined(XP_WIN)
+#  include "windef.h"
+#  include "winnetwk.h"
+#  include "npapi.h"
+#  include "WinUtils.h"
+#endif  // #if defined (XP_WIN)
+
+#if defined(MOZ_WIDGET_GTK) || defined(XP_MACOSX)
+#  include "NativeKeyBindings.h"
+#endif  // #if defined(MOZ_WIDGET_GTK) || defined(XP_MACOSX)
+
+namespace mozilla {
+
+/******************************************************************************
+ * Global helper methods
+ ******************************************************************************/
+
+const char* ToChar(EventMessage aEventMessage) {
+  switch (aEventMessage) {
+#define NS_EVENT_MESSAGE(aMessage) \
+  case aMessage:                   \
+    return #aMessage;
+
+#include "mozilla/EventMessageList.h"
+
+#undef NS_EVENT_MESSAGE
+    default:
+      return "illegal event message";
+  }
+}
+
+const char* ToChar(EventClassID aEventClassID) {
+  switch (aEventClassID) {
+#define NS_ROOT_EVENT_CLASS(aPrefix, aName) \
+  case eBasic##aName##Class:                \
+    return "eBasic" #aName "Class";
+
+#define NS_EVENT_CLASS(aPrefix, aName) \
+  case e##aName##Class:                \
+    return "e" #aName "Class";
+
+#include "mozilla/EventClassList.h"
+
+#undef NS_EVENT_CLASS
+#undef NS_ROOT_EVENT_CLASS
+    default:
+      return "illegal event class ID";
+  }
+}
+
+const nsCString ToString(KeyNameIndex aKeyNameIndex) {
+  if (aKeyNameIndex == KEY_NAME_INDEX_USE_STRING) {
+    return "USE_STRING"_ns;
+  }
+  nsAutoString keyName;
+  WidgetKeyboardEvent::GetDOMKeyName(aKeyNameIndex, keyName);
+  return NS_ConvertUTF16toUTF8(keyName);
+}
+
+const nsCString ToString(CodeNameIndex aCodeNameIndex) {
+  if (aCodeNameIndex == CODE_NAME_INDEX_USE_STRING) {
+    return "USE_STRING"_ns;
+  }
+  nsAutoString codeName;
+  WidgetKeyboardEvent::GetDOMCodeName(aCodeNameIndex, codeName);
+  return NS_ConvertUTF16toUTF8(codeName);
+}
+
+const char* ToChar(Command aCommand) {
+  if (aCommand == Command::DoNothing) {
+    return "CommandDoNothing";
+  }
+
+  switch (aCommand) {
+#define NS_DEFINE_COMMAND(aName, aCommandStr) \
+  case Command::aName:                        \
+    return "Command::" #aName;
+#define NS_DEFINE_COMMAND_WITH_PARAM(aName, aCommandStr, aParam) \
+  case Command::aName:                                           \
+    return "Command::" #aName;
+#define NS_DEFINE_COMMAND_NO_EXEC_COMMAND(aName) \
+  case Command::aName:                           \
+    return "Command::" #aName;
+
+#include "mozilla/CommandList.h"
+
+#undef NS_DEFINE_COMMAND
+#undef NS_DEFINE_COMMAND_WITH_PARAM
+#undef NS_DEFINE_COMMAND_NO_EXEC_COMMAND
+
+    default:
+      return "illegal command value";
+  }
+}
+
+const nsCString GetDOMKeyCodeName(uint32_t aKeyCode) {
+  switch (aKeyCode) {
+#define NS_DISALLOW_SAME_KEYCODE
+#define NS_DEFINE_VK(aDOMKeyName, aDOMKeyCode) \
+  case aDOMKeyCode:                            \
+    return nsLiteralCString(#aDOMKeyName);
+
+#include "mozilla/VirtualKeyCodeList.h"
+
+#undef NS_DEFINE_VK
+#undef NS_DISALLOW_SAME_KEYCODE
+
+    default:
+      return nsPrintfCString("Invalid DOM keyCode (0x%08X)", aKeyCode);
+  }
+}
+
+bool IsValidRawTextRangeValue(RawTextRangeType aRawTextRangeType) {
+  switch (static_cast<TextRangeType>(aRawTextRangeType)) {
+    case TextRangeType::eUninitialized:
+    case TextRangeType::eCaret:
+    case TextRangeType::eRawClause:
+    case TextRangeType::eSelectedRawClause:
+    case TextRangeType::eConvertedClause:
+    case TextRangeType::eSelectedClause:
+      return true;
+    default:
+      return false;
+  }
+}
+
+RawTextRangeType ToRawTextRangeType(TextRangeType aTextRangeType) {
+  return static_cast<RawTextRangeType>(aTextRangeType);
+}
+
+TextRangeType ToTextRangeType(RawTextRangeType aRawTextRangeType) {
+  MOZ_ASSERT(IsValidRawTextRangeValue(aRawTextRangeType));
+  return static_cast<TextRangeType>(aRawTextRangeType);
+}
+
+const char* ToChar(TextRangeType aTextRangeType) {
+  switch (aTextRangeType) {
+    case TextRangeType::eUninitialized:
+      return "TextRangeType::eUninitialized";
+    case TextRangeType::eCaret:
+      return "TextRangeType::eCaret";
+    case TextRangeType::eRawClause:
+      return "TextRangeType::eRawClause";
+    case TextRangeType::eSelectedRawClause:
+      return "TextRangeType::eSelectedRawClause";
+    case TextRangeType::eConvertedClause:
+      return "TextRangeType::eConvertedClause";
+    case TextRangeType::eSelectedClause:
+      return "TextRangeType::eSelectedClause";
+    default:
+      return "Invalid TextRangeType";
+  }
+}
+
+SelectionType ToSelectionType(TextRangeType aTextRangeType) {
+  switch (aTextRangeType) {
+    case TextRangeType::eRawClause:
+      return SelectionType::eIMERawClause;
+    case TextRangeType::eSelectedRawClause:
+      return SelectionType::eIMESelectedRawClause;
+    case TextRangeType::eConvertedClause:
+      return SelectionType::eIMEConvertedClause;
+    case TextRangeType::eSelectedClause:
+      return SelectionType::eIMESelectedClause;
+    default:
+      MOZ_CRASH("TextRangeType is invalid");
+      return SelectionType::eNormal;
+  }
+}
+
+/******************************************************************************
+ * non class method implementation
+ ******************************************************************************/
+
+static nsTHashMap<nsDepCharHashKey, Command>* sCommandHashtable = nullptr;
+
+Command GetInternalCommand(const char* aCommandName,
+                           const nsCommandParams* aCommandParams) {
+  if (!aCommandName) {
+    return Command::DoNothing;
+  }
+
+  // Special cases for "cmd_align".  It's mapped to multiple internal commands
+  // with additional param.  Therefore, we cannot handle it with the hashtable.
+  if (!strcmp(aCommandName, "cmd_align")) {
+    if (!aCommandParams) {
+      // Note that if this is called by EditorCommand::IsCommandEnabled(),
+      // it cannot set aCommandParams.  So, don't warn in this case even though
+      // this is illegal case for DoCommandParams().
+      return Command::FormatJustify;
+    }
+    nsAutoCString cValue;
+    nsresult rv = aCommandParams->GetCString("state_attribute", cValue);
+    if (NS_FAILED(rv)) {
+      nsString value;  // Avoid copying the string buffer with using nsString.
+      rv = aCommandParams->GetString("state_attribute", value);
+      if (NS_FAILED(rv)) {
+        return Command::FormatJustifyNone;
+      }
+      CopyUTF16toUTF8(value, cValue);
+    }
+    if (cValue.LowerCaseEqualsASCII("left")) {
+      return Command::FormatJustifyLeft;
+    }
+    if (cValue.LowerCaseEqualsASCII("right")) {
+      return Command::FormatJustifyRight;
+    }
+    if (cValue.LowerCaseEqualsASCII("center")) {
+      return Command::FormatJustifyCenter;
+    }
+    if (cValue.LowerCaseEqualsASCII("justify")) {
+      return Command::FormatJustifyFull;
+    }
+    if (cValue.IsEmpty()) {
+      return Command::FormatJustifyNone;
+    }
+    return Command::DoNothing;
+  }
+
+  if (!sCommandHashtable) {
+    sCommandHashtable = new nsTHashMap<nsDepCharHashKey, Command>();
+#define NS_DEFINE_COMMAND(aName, aCommandStr) \
+  sCommandHashtable->InsertOrUpdate(#aCommandStr, Command::aName);
+
+#define NS_DEFINE_COMMAND_WITH_PARAM(aName, aCommandStr, aParam)
+
+#define NS_DEFINE_COMMAND_NO_EXEC_COMMAND(aName)
+
+#include "mozilla/CommandList.h"
+
+#undef NS_DEFINE_COMMAND
+#undef NS_DEFINE_COMMAND_WITH_PARAM
+#undef NS_DEFINE_COMMAND_NO_EXEC_COMMAND
+  }
+  Command command = Command::DoNothing;
+  if (!sCommandHashtable->Get(aCommandName, &command)) {
+    return Command::DoNothing;
+  }
+  return command;
+}
+
+/******************************************************************************
+ * As*Event() implementation
+ ******************************************************************************/
+
+#define NS_ROOT_EVENT_CLASS(aPrefix, aName)
+#define NS_EVENT_CLASS(aPrefix, aName)                         \
+  aPrefix##aName* WidgetEvent::As##aName() { return nullptr; } \
+                                                               \
+  const aPrefix##aName* WidgetEvent::As##aName() const {       \
+    return const_cast<WidgetEvent*>(this)->As##aName();        \
+  }
+
+#include "mozilla/EventClassList.h"
+
+#undef NS_EVENT_CLASS
+#undef NS_ROOT_EVENT_CLASS
+
+/******************************************************************************
+ * mozilla::WidgetEvent
+ *
+ * Event struct type checking methods.
+ ******************************************************************************/
+
+bool WidgetEvent::IsQueryContentEvent() const {
+  return mClass == eQueryContentEventClass;
+}
+
+bool WidgetEvent::IsSelectionEvent() const {
+  return mClass == eSelectionEventClass;
+}
+
+bool WidgetEvent::IsContentCommandEvent() const {
+  return mClass == eContentCommandEventClass;
+}
+
+/******************************************************************************
+ * mozilla::WidgetEvent
+ *
+ * Event message checking methods.
+ ******************************************************************************/
+
+bool WidgetEvent::HasMouseEventMessage() const {
+  switch (mMessage) {
+    case eMouseDown:
+    case eMouseUp:
+    case eMouseClick:
+    case eMouseDoubleClick:
+    case eMouseAuxClick:
+    case eMouseEnterIntoWidget:
+    case eMouseExitFromWidget:
+    case eMouseActivate:
+    case eMouseOver:
+    case eMouseOut:
+    case eMouseHitTest:
+    case eMouseMove:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool WidgetEvent::HasDragEventMessage() const {
+  switch (mMessage) {
+    case eDragEnter:
+    case eDragOver:
+    case eDragExit:
+    case eDrag:
+    case eDragEnd:
+    case eDragStart:
+    case eDrop:
+    case eDragLeave:
+      return true;
+    default:
+      return false;
+  }
+}
+
+/* static */
+bool WidgetEvent::IsKeyEventMessage(EventMessage aMessage) {
+  switch (aMessage) {
+    case eKeyDown:
+    case eKeyPress:
+    case eKeyUp:
+    case eAccessKeyNotFound:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool WidgetEvent::HasIMEEventMessage() const {
+  switch (mMessage) {
+    case eCompositionStart:
+    case eCompositionEnd:
+    case eCompositionUpdate:
+    case eCompositionChange:
+    case eCompositionCommitAsIs:
+    case eCompositionCommit:
+      return true;
+    default:
+      return false;
+  }
+}
+
+/******************************************************************************
+ * mozilla::WidgetEvent
+ *
+ * Specific event checking methods.
+ ******************************************************************************/
+
+bool WidgetEvent::CanBeSentToRemoteProcess() const {
+  // If this event is explicitly marked as shouldn't be sent to remote process,
+  // just return false.
+  if (IsCrossProcessForwardingStopped()) {
+    return false;
+  }
+
+  if (mClass == eKeyboardEventClass || mClass == eWheelEventClass) {
+    return true;
+  }
+
+  switch (mMessage) {
+    case eMouseDown:
+    case eMouseUp:
+    case eMouseMove:
+    case eMouseExploreByTouch:
+    case eContextMenu:
+    case eMouseEnterIntoWidget:
+    case eMouseExitFromWidget:
+    case eMouseTouchDrag:
+    case eTouchStart:
+    case eTouchMove:
+    case eTouchEnd:
+    case eTouchCancel:
+    case eDragOver:
+    case eDragExit:
+    case eDrop:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool WidgetEvent::WillBeSentToRemoteProcess() const {
+  // This event won't be posted to remote process if it's already explicitly
+  // stopped.
+  if (IsCrossProcessForwardingStopped()) {
+    return false;
+  }
+
+  // When mOriginalTarget is nullptr, this method shouldn't be used.
+  if (NS_WARN_IF(!mOriginalTarget)) {
+    return false;
+  }
+
+  return EventStateManager::IsTopLevelRemoteTarget(
+      nsIContent::FromEventTarget(mOriginalTarget));
+}
+
+bool WidgetEvent::IsIMERelatedEvent() const {
+  return HasIMEEventMessage() || IsQueryContentEvent() || IsSelectionEvent();
+}
+
+bool WidgetEvent::IsUsingCoordinates() const {
+  const WidgetMouseEvent* mouseEvent = AsMouseEvent();
+  if (mouseEvent) {
+    return !mouseEvent->IsContextMenuKeyEvent();
+  }
+  return !HasKeyEventMessage() && !IsIMERelatedEvent() &&
+         !IsContentCommandEvent();
+}
+
+bool WidgetEvent::IsTargetedAtFocusedWindow() const {
+  const WidgetMouseEvent* mouseEvent = AsMouseEvent();
+  if (mouseEvent) {
+    return mouseEvent->IsContextMenuKeyEvent();
+  }
+  return HasKeyEventMessage() || IsIMERelatedEvent() || IsContentCommandEvent();
+}
+
+bool WidgetEvent::IsTargetedAtFocusedContent() const {
+  const WidgetMouseEvent* mouseEvent = AsMouseEvent();
+  if (mouseEvent) {
+    return mouseEvent->IsContextMenuKeyEvent();
+  }
+  return HasKeyEventMessage() || IsIMERelatedEvent();
+}
+
+bool WidgetEvent::IsAllowedToDispatchDOMEvent() const {
+  switch (mClass) {
+    case eMouseEventClass:
+      if (mMessage == eMouseTouchDrag) {
+        return false;
+      }
+      [[fallthrough]];
+    case ePointerEventClass:
+      // We want synthesized mouse moves to cause mouseover and mouseout
+      // DOM events (EventStateManager::PreHandleEvent), but not mousemove
+      // DOM events.
+      // Synthesized button up events also do not cause DOM events because they
+      // do not have a reliable mRefPoint.
+      return AsMouseEvent()->mReason == WidgetMouseEvent::eReal;
+
+    case eWheelEventClass: {
+      // wheel event whose all delta values are zero by user pref applied, it
+      // shouldn't cause a DOM event.
+      const WidgetWheelEvent* wheelEvent = AsWheelEvent();
+      return wheelEvent->mDeltaX != 0.0 || wheelEvent->mDeltaY != 0.0 ||
+             wheelEvent->mDeltaZ != 0.0;
+    }
+    case eTouchEventClass:
+      return mMessage != eTouchPointerCancel;
+    // Following events are handled in EventStateManager, so, we don't need to
+    // dispatch DOM event for them into the DOM tree.
+    case eQueryContentEventClass:
+    case eSelectionEventClass:
+    case eContentCommandEventClass:
+      return false;
+
+    default:
+      return true;
+  }
+}
+
+bool WidgetEvent::IsAllowedToDispatchInSystemGroup() const {
+  // We don't expect to implement default behaviors with pointer events because
+  // if we do, prevent default on mouse events can't prevent default behaviors
+  // anymore.
+  return mClass != ePointerEventClass;
+}
+
+bool WidgetEvent::IsBlockedForFingerprintingResistance() const {
+  switch (mClass) {
+    case eKeyboardEventClass: {
+      const WidgetKeyboardEvent* keyboardEvent = AsKeyboardEvent();
+
+      return (keyboardEvent->mKeyNameIndex == KEY_NAME_INDEX_Alt ||
+              keyboardEvent->mKeyNameIndex == KEY_NAME_INDEX_Shift ||
+              keyboardEvent->mKeyNameIndex == KEY_NAME_INDEX_Control ||
+              keyboardEvent->mKeyNameIndex == KEY_NAME_INDEX_AltGraph);
+    }
+    case ePointerEventClass: {
+      const WidgetPointerEvent* pointerEvent = AsPointerEvent();
+
+      // We suppress the pointer events if it is not primary for fingerprinting
+      // resistance. It is because of that we want to spoof any pointer event
+      // into a mouse pointer event and the mouse pointer event only has
+      // isPrimary as true.
+      return !pointerEvent->mIsPrimary;
+    }
+    default:
+      return false;
+  }
+}
+
+bool WidgetEvent::AllowFlushingPendingNotifications() const {
+  if (mClass != eQueryContentEventClass) {
+    return true;
+  }
+  // If the dispatcher does not want a flush of pending notifications, it may
+  // be caused by that it's unsafe.  Therefore, we should allow handlers to
+  // flush pending things only when the dispatcher requires the latest content
+  // layout.
+  return AsQueryContentEvent()->mNeedsToFlushLayout;
+}
+
+/******************************************************************************
+ * mozilla::WidgetEvent
+ *
+ * Misc methods.
+ ******************************************************************************/
+
+static dom::EventTarget* GetTargetForDOMEvent(dom::EventTarget* aTarget) {
+  return aTarget ? aTarget->GetTargetForDOMEvent() : nullptr;
+}
+
+dom::EventTarget* WidgetEvent::GetDOMEventTarget() const {
+  return GetTargetForDOMEvent(mTarget);
+}
+
+dom::EventTarget* WidgetEvent::GetCurrentDOMEventTarget() const {
+  return GetTargetForDOMEvent(mCurrentTarget);
+}
+
+dom::EventTarget* WidgetEvent::GetOriginalDOMEventTarget() const {
+  if (mOriginalTarget) {
+    return GetTargetForDOMEvent(mOriginalTarget);
+  }
+  return GetDOMEventTarget();
+}
+
+void WidgetEvent::PreventDefault(bool aCalledByDefaultHandler,
+                                 nsIPrincipal* aPrincipal) {
+  if (mMessage == ePointerDown) {
+    if (aCalledByDefaultHandler) {
+      // Shouldn't prevent default on pointerdown by default handlers to stop
+      // firing legacy mouse events. Use MOZ_ASSERT to catch incorrect usages
+      // in debug builds.
+      MOZ_ASSERT(false);
+      return;
+    }
+    if (aPrincipal) {
+      nsAutoString addonId;
+      Unused << NS_WARN_IF(NS_FAILED(aPrincipal->GetAddonId(addonId)));
+      if (!addonId.IsEmpty()) {
+        // Ignore the case that it's called by a web extension.
+        return;
+      }
+    }
+  }
+  mFlags.PreventDefault(aCalledByDefaultHandler);
+}
+
+bool WidgetEvent::IsUserAction() const {
+  if (!IsTrusted()) {
+    return false;
+  }
+  // FYI: eMouseScrollEventClass and ePointerEventClass represent
+  //      user action but they are synthesized events.
+  switch (mClass) {
+    case eKeyboardEventClass:
+    case eCompositionEventClass:
+    case eMouseScrollEventClass:
+    case eWheelEventClass:
+    case eGestureNotifyEventClass:
+    case eSimpleGestureEventClass:
+    case eTouchEventClass:
+    case eCommandEventClass:
+    case eContentCommandEventClass:
+      return true;
+    case eMouseEventClass:
+    case eDragEventClass:
+    case ePointerEventClass:
+      return AsMouseEvent()->IsReal();
+    default:
+      return false;
+  }
+}
+
+/******************************************************************************
+ * mozilla::WidgetInputEvent
+ ******************************************************************************/
+
+/* static */
+Modifier WidgetInputEvent::GetModifier(const nsAString& aDOMKeyName) {
+  if (aDOMKeyName.EqualsLiteral("Accel")) {
+    return AccelModifier();
+  }
+  KeyNameIndex keyNameIndex = WidgetKeyboardEvent::GetKeyNameIndex(aDOMKeyName);
+  return WidgetKeyboardEvent::GetModifierForKeyName(keyNameIndex);
+}
+
+/* static */
+Modifier WidgetInputEvent::AccelModifier() {
+  static Modifier sAccelModifier = MODIFIER_NONE;
+  if (sAccelModifier == MODIFIER_NONE) {
+    switch (StaticPrefs::ui_key_accelKey()) {
+      case dom::KeyboardEvent_Binding::DOM_VK_META:
+      case dom::KeyboardEvent_Binding::DOM_VK_WIN:
+        sAccelModifier = MODIFIER_META;
+        break;
+      case dom::KeyboardEvent_Binding::DOM_VK_ALT:
+        sAccelModifier = MODIFIER_ALT;
+        break;
+      case dom::KeyboardEvent_Binding::DOM_VK_CONTROL:
+        sAccelModifier = MODIFIER_CONTROL;
+        break;
+      default:
+#ifdef XP_MACOSX
+        sAccelModifier = MODIFIER_META;
+#else
+        sAccelModifier = MODIFIER_CONTROL;
+#endif
+        break;
+    }
+  }
+  return sAccelModifier;
+}
+
+/******************************************************************************
+ * mozilla::WidgetMouseEventBase (MouseEvents.h)
+ ******************************************************************************/
+
+bool WidgetMouseEventBase::InputSourceSupportsHover() const {
+  switch (mInputSource) {
+    case dom::MouseEvent_Binding::MOZ_SOURCE_MOUSE:
+    case dom::MouseEvent_Binding::MOZ_SOURCE_PEN:
+    case dom::MouseEvent_Binding::MOZ_SOURCE_ERASER:
+      return true;
+    case dom::MouseEvent_Binding::MOZ_SOURCE_TOUCH:
+    case dom::MouseEvent_Binding::MOZ_SOURCE_UNKNOWN:
+    case dom::MouseEvent_Binding::MOZ_SOURCE_KEYBOARD:
+    case dom::MouseEvent_Binding::MOZ_SOURCE_CURSOR:
+    default:
+      return false;
+  }
+}
+
+/******************************************************************************
+ * mozilla::WidgetMouseEvent (MouseEvents.h)
+ ******************************************************************************/
+
+/* static */
+bool WidgetMouseEvent::IsMiddleClickPasteEnabled() {
+  return Preferences::GetBool("middlemouse.paste", false);
+}
+
+#ifdef DEBUG
+void WidgetMouseEvent::AssertContextMenuEventButtonConsistency() const {
+  if (mMessage != eContextMenu) {
+    return;
+  }
+
+  if (mContextMenuTrigger == eNormal) {
+    NS_WARNING_ASSERTION(mButton == MouseButton::eSecondary,
+                         "eContextMenu events with eNormal trigger should use "
+                         "secondary mouse button");
+  } else {
+    NS_WARNING_ASSERTION(mButton == MouseButton::ePrimary,
+                         "eContextMenu events with non-eNormal trigger should "
+                         "use primary mouse button");
+  }
+
+  if (mContextMenuTrigger == eControlClick) {
+    NS_WARNING_ASSERTION(IsControl(),
+                         "eContextMenu events with eControlClick trigger "
+                         "should return true from IsControl()");
+  }
+}
+#endif
+
+/******************************************************************************
+ * mozilla::WidgetDragEvent (MouseEvents.h)
+ ******************************************************************************/
+
+void WidgetDragEvent::InitDropEffectForTests() {
+  MOZ_ASSERT(mFlags.mIsSynthesizedForTests);
+
+  nsCOMPtr<nsIDragSession> session = nsContentUtils::GetDragSession();
+  if (NS_WARN_IF(!session)) {
+    return;
+  }
+
+  uint32_t effectAllowed = session->GetEffectAllowedForTests();
+  uint32_t desiredDropEffect = nsIDragService::DRAGDROP_ACTION_NONE;
+#ifdef XP_MACOSX
+  if (IsAlt()) {
+    desiredDropEffect = IsMeta() ? nsIDragService::DRAGDROP_ACTION_LINK
+                                 : nsIDragService::DRAGDROP_ACTION_COPY;
+  }
+#else
+  // On Linux, we know user's intention from API, but we should use
+  // same modifiers as Windows for tests because GNOME on Ubuntu use
+  // them and that makes each test simpler.
+  if (IsControl()) {
+    desiredDropEffect = IsShift() ? nsIDragService::DRAGDROP_ACTION_LINK
+                                  : nsIDragService::DRAGDROP_ACTION_COPY;
+  } else if (IsShift()) {
+    desiredDropEffect = nsIDragService::DRAGDROP_ACTION_MOVE;
+  }
+#endif  // #ifdef XP_MACOSX #else
+  // First, use modifier state for preferring action which is explicitly
+  // specified by the synthesizer.
+  if (!(desiredDropEffect &= effectAllowed)) {
+    // Otherwise, use an action which is allowed at starting the session.
+    desiredDropEffect = effectAllowed;
+  }
+  if (desiredDropEffect & nsIDragService::DRAGDROP_ACTION_MOVE) {
+    session->SetDragAction(nsIDragService::DRAGDROP_ACTION_MOVE);
+  } else if (desiredDropEffect & nsIDragService::DRAGDROP_ACTION_COPY) {
+    session->SetDragAction(nsIDragService::DRAGDROP_ACTION_COPY);
+  } else if (desiredDropEffect & nsIDragService::DRAGDROP_ACTION_LINK) {
+    session->SetDragAction(nsIDragService::DRAGDROP_ACTION_LINK);
+  } else {
+    session->SetDragAction(nsIDragService::DRAGDROP_ACTION_NONE);
+  }
+}
+
+/******************************************************************************
+ * mozilla::WidgetWheelEvent (MouseEvents.h)
+ ******************************************************************************/
+
+/* static */
+double WidgetWheelEvent::ComputeOverriddenDelta(double aDelta,
+                                                bool aIsForVertical) {
+  if (!StaticPrefs::mousewheel_system_scroll_override_enabled()) {
+    return aDelta;
+  }
+  int32_t intFactor =
+      aIsForVertical
+          ? StaticPrefs::mousewheel_system_scroll_override_vertical_factor()
+          : StaticPrefs::mousewheel_system_scroll_override_horizontal_factor();
+  // Making the scroll speed slower doesn't make sense. So, ignore odd factor
+  // which is less than 1.0.
+  if (intFactor <= 100) {
+    return aDelta;
+  }
+  double factor = static_cast<double>(intFactor) / 100;
+  return aDelta * factor;
+}
+
+double WidgetWheelEvent::OverriddenDeltaX() const {
+  if (!mAllowToOverrideSystemScrollSpeed ||
+      mDeltaMode != dom::WheelEvent_Binding::DOM_DELTA_LINE ||
+      mCustomizedByUserPrefs) {
+    return mDeltaX;
+  }
+  return ComputeOverriddenDelta(mDeltaX, false);
+}
+
+double WidgetWheelEvent::OverriddenDeltaY() const {
+  if (!mAllowToOverrideSystemScrollSpeed ||
+      mDeltaMode != dom::WheelEvent_Binding::DOM_DELTA_LINE ||
+      mCustomizedByUserPrefs) {
+    return mDeltaY;
+  }
+  return ComputeOverriddenDelta(mDeltaY, true);
+}
+
+/******************************************************************************
+ * mozilla::WidgetKeyboardEvent (TextEvents.h)
+ ******************************************************************************/
+
+#define NS_DEFINE_KEYNAME(aCPPName, aDOMKeyName) (u"" aDOMKeyName),
+const char16_t* const WidgetKeyboardEvent::kKeyNames[] = {
+#include "mozilla/KeyNameList.h"
+};
+#undef NS_DEFINE_KEYNAME
+
+#define NS_DEFINE_PHYSICAL_KEY_CODE_NAME(aCPPName, aDOMCodeName) \
+  (u"" aDOMCodeName),
+const char16_t* const WidgetKeyboardEvent::kCodeNames[] = {
+#include "mozilla/PhysicalKeyCodeNameList.h"
+};
+#undef NS_DEFINE_PHYSICAL_KEY_CODE_NAME
+
+WidgetKeyboardEvent::KeyNameIndexHashtable*
+    WidgetKeyboardEvent::sKeyNameIndexHashtable = nullptr;
+WidgetKeyboardEvent::CodeNameIndexHashtable*
+    WidgetKeyboardEvent::sCodeNameIndexHashtable = nullptr;
+
+void WidgetKeyboardEvent::InitAllEditCommands(
+    const Maybe<WritingMode>& aWritingMode) {
+  // If this event is synthesized for tests, we don't need to retrieve the
+  // command via the main process.  So, we don't need widget and can trust
+  // the event.
+  if (!mFlags.mIsSynthesizedForTests) {
+    // If the event was created without widget, e.g., created event in chrome
+    // script, this shouldn't execute native key bindings.
+    if (NS_WARN_IF(!mWidget)) {
+      return;
+    }
+
+    // This event should be trusted event here and we shouldn't expose native
+    // key binding information to web contents with untrusted events.
+    if (NS_WARN_IF(!IsTrusted())) {
+      return;
+    }
+
+    MOZ_ASSERT(
+        XRE_IsParentProcess(),
+        "It's too expensive to retrieve all edit commands from remote process");
+    MOZ_ASSERT(!AreAllEditCommandsInitialized(),
+               "Shouldn't be called two or more times");
+  }
+
+  DebugOnly<bool> okIgnored = InitEditCommandsFor(
+      NativeKeyBindingsType::SingleLineEditor, aWritingMode);
+  NS_WARNING_ASSERTION(okIgnored,
+                       "InitEditCommandsFor(NativeKeyBindingsType::"
+                       "SingleLineEditor) failed, but ignored");
+  okIgnored =
+      InitEditCommandsFor(NativeKeyBindingsType::MultiLineEditor, aWritingMode);
+  NS_WARNING_ASSERTION(okIgnored,
+                       "InitEditCommandsFor(NativeKeyBindingsType::"
+                       "MultiLineEditor) failed, but ignored");
+  okIgnored =
+      InitEditCommandsFor(NativeKeyBindingsType::RichTextEditor, aWritingMode);
+  NS_WARNING_ASSERTION(okIgnored,
+                       "InitEditCommandsFor(NativeKeyBindingsType::"
+                       "RichTextEditor) failed, but ignored");
+}
+
+bool WidgetKeyboardEvent::InitEditCommandsFor(
+    NativeKeyBindingsType aType, const Maybe<WritingMode>& aWritingMode) {
+  bool& initialized = IsEditCommandsInitializedRef(aType);
+  if (initialized) {
+    return true;
+  }
+  nsTArray<CommandInt>& commands = EditCommandsRef(aType);
+
+  // If this event is synthesized for tests, we shouldn't access customized
+  // shortcut settings of the environment.  Therefore, we don't need to check
+  // whether `widget` is set or not.  And we can treat synthesized events are
+  // always trusted.
+  if (mFlags.mIsSynthesizedForTests) {
+    MOZ_DIAGNOSTIC_ASSERT(IsTrusted());
+#if defined(MOZ_WIDGET_GTK) || defined(XP_MACOSX)
+    // TODO: We should implement `NativeKeyBindings` for Windows and Android
+    //       too in bug 1301497 for getting rid of the #if.
+    widget::NativeKeyBindings::GetEditCommandsForTests(aType, *this,
+                                                       aWritingMode, commands);
+#endif
+    initialized = true;
+    return true;
+  }
+
+  if (NS_WARN_IF(!mWidget) || NS_WARN_IF(!IsTrusted())) {
+    return false;
+  }
+  // `nsIWidget::GetEditCommands()` will retrieve `WritingMode` at selection
+  // again, but it should be almost zero-cost since `TextEventDispatcher`
+  // caches the value.
+  nsCOMPtr<nsIWidget> widget = mWidget;
+  initialized = widget->GetEditCommands(aType, *this, commands);
+  return initialized;
+}
+
+bool WidgetKeyboardEvent::ExecuteEditCommands(NativeKeyBindingsType aType,
+                                              DoCommandCallback aCallback,
+                                              void* aCallbackData) {
+  // If the event was created without widget, e.g., created event in chrome
+  // script, this shouldn't execute native key bindings.
+  if (NS_WARN_IF(!mWidget)) {
+    return false;
+  }
+
+  // This event should be trusted event here and we shouldn't expose native
+  // key binding information to web contents with untrusted events.
+  if (NS_WARN_IF(!IsTrusted())) {
+    return false;
+  }
+
+  if (!IsEditCommandsInitializedRef(aType)) {
+    Maybe<WritingMode> writingMode;
+    if (RefPtr<widget::TextEventDispatcher> textEventDispatcher =
+            mWidget->GetTextEventDispatcher()) {
+      writingMode = textEventDispatcher->MaybeQueryWritingModeAtSelection();
+    }
+    if (NS_WARN_IF(!InitEditCommandsFor(aType, writingMode))) {
+      return false;
+    }
+  }
+
+  const nsTArray<CommandInt>& commands = EditCommandsRef(aType);
+  if (commands.IsEmpty()) {
+    return false;
+  }
+
+  for (CommandInt command : commands) {
+    aCallback(static_cast<Command>(command), aCallbackData);
+  }
+  return true;
+}
+
+bool WidgetKeyboardEvent::ShouldCauseKeypressEvents() const {
+  // Currently, we don't dispatch keypress events of modifier keys and
+  // dead keys.
+  switch (mKeyNameIndex) {
+    case KEY_NAME_INDEX_Alt:
+    case KEY_NAME_INDEX_AltGraph:
+    case KEY_NAME_INDEX_CapsLock:
+    case KEY_NAME_INDEX_Control:
+    case KEY_NAME_INDEX_Fn:
+    case KEY_NAME_INDEX_FnLock:
+    // case KEY_NAME_INDEX_Hyper:
+    case KEY_NAME_INDEX_Meta:
+    case KEY_NAME_INDEX_NumLock:
+    case KEY_NAME_INDEX_ScrollLock:
+    case KEY_NAME_INDEX_Shift:
+    // case KEY_NAME_INDEX_Super:
+    case KEY_NAME_INDEX_Symbol:
+    case KEY_NAME_INDEX_SymbolLock:
+    case KEY_NAME_INDEX_Dead:
+      return false;
+    default:
+      return true;
+  }
+}
+
+static bool HasASCIIDigit(const ShortcutKeyCandidateArray& aCandidates) {
+  for (uint32_t i = 0; i < aCandidates.Length(); ++i) {
+    uint32_t ch = aCandidates[i].mCharCode;
+    if (ch >= '0' && ch <= '9') return true;
+  }
+  return false;
+}
+
+static bool CharsCaseInsensitiveEqual(uint32_t aChar1, uint32_t aChar2) {
+  return aChar1 == aChar2 || (IS_IN_BMP(aChar1) && IS_IN_BMP(aChar2) &&
+                              ToLowerCase(static_cast<char16_t>(aChar1)) ==
+                                  ToLowerCase(static_cast<char16_t>(aChar2)));
+}
+
+static bool IsCaseChangeableChar(uint32_t aChar) {
+  return IS_IN_BMP(aChar) && ToLowerCase(static_cast<char16_t>(aChar)) !=
+                                 ToUpperCase(static_cast<char16_t>(aChar));
+}
+
+void WidgetKeyboardEvent::GetShortcutKeyCandidates(
+    ShortcutKeyCandidateArray& aCandidates) const {
+  MOZ_ASSERT(aCandidates.IsEmpty(), "aCandidates must be empty");
+
+  using ShiftState = ShortcutKeyCandidate::ShiftState;
+  using SkipIfEarlierHandlerDisabled =
+      ShortcutKeyCandidate::SkipIfEarlierHandlerDisabled;
+
+  // ShortcutKeyCandidate::mCharCode is a candidate charCode.
+  // ShortcutKeyCandidate::mShiftState means the mCharCode should be tried to
+  // execute a command with/without shift key state. If this is Ignorable,
+  // the shifted key state should be ignored. Otherwise, don't ignore the state.
+  // the priority of the charCodes are (shift key is not pressed):
+  //   0: PseudoCharCode()/ShiftState::MatchExactly,
+  //   1: unshiftedCharCodes[0]/ShiftState::MatchExactly,
+  //   2: unshiftedCharCodes[1]/ShiftState::MatchExactly...
+  // the priority of the charCodes are (shift key is pressed):
+  //   0: PseudoCharCode()/ShiftState::MatchExactly,
+  //   1: shiftedCharCodes[0]/ShiftState::MatchExactly,
+  //   2: shiftedCharCodes[0]/ShiftState::Ignorable,
+  //   3: shiftedCharCodes[1]/ShiftState::MatchExactly,
+  //   4: shiftedCharCodes[1]/ShiftState::Ignorable...
+  uint32_t pseudoCharCode = PseudoCharCode();
+  if (pseudoCharCode) {
+    ShortcutKeyCandidate key(pseudoCharCode, ShiftState::MatchExactly,
+                             SkipIfEarlierHandlerDisabled::No);
+    aCandidates.AppendElement(key);
+  }
+
+  uint32_t len = mAlternativeCharCodes.Length();
+  if (!IsShift()) {
+    for (uint32_t i = 0; i < len; ++i) {
+      uint32_t ch = mAlternativeCharCodes[i].mUnshiftedCharCode;
+      if (!ch || ch == pseudoCharCode) {
+        continue;
+      }
+      ShortcutKeyCandidate key(ch, ShiftState::MatchExactly,
+                               SkipIfEarlierHandlerDisabled::No);
+      aCandidates.AppendElement(key);
+    }
+    // If unshiftedCharCodes doesn't have numeric but shiftedCharCode has it,
+    // this keyboard layout is AZERTY or similar layout, probably.
+    // In this case, Accel+[0-9] should be accessible without shift key.
+    // However, the priority should be lowest.
+    if (!HasASCIIDigit(aCandidates)) {
+      for (uint32_t i = 0; i < len; ++i) {
+        uint32_t ch = mAlternativeCharCodes[i].mShiftedCharCode;
+        if (ch >= '0' && ch <= '9') {
+          ShortcutKeyCandidate key(
+              ch, ShiftState::MatchExactly,
+              // Ctrl + `-` in the French keyboard layout should not match with
+              // Ctrl + `6` shortcut when it's already fully zoomed out.
+              SkipIfEarlierHandlerDisabled::Yes);
+          aCandidates.AppendElement(key);
+          break;
+        }
+      }
+    }
+  } else {
+    for (uint32_t i = 0; i < len; ++i) {
+      uint32_t ch = mAlternativeCharCodes[i].mShiftedCharCode;
+      if (!ch) {
+        continue;
+      }
+
+      if (ch != pseudoCharCode) {
+        ShortcutKeyCandidate key(ch, ShiftState::MatchExactly,
+                                 SkipIfEarlierHandlerDisabled::No);
+        aCandidates.AppendElement(key);
+      }
+
+      // If the char is an alphabet, the shift key state should not be
+      // ignored. E.g., Ctrl+Shift+C should not execute Ctrl+C.
+
+      // And checking the charCode is same as unshiftedCharCode too.
+      // E.g., for Ctrl+Shift+(Plus of Numpad) should not run Ctrl+Plus.
+      uint32_t unshiftCh = mAlternativeCharCodes[i].mUnshiftedCharCode;
+      if (CharsCaseInsensitiveEqual(ch, unshiftCh)) {
+        continue;
+      }
+
+      // On the Hebrew keyboard layout on Windows, the unshifted char is a
+      // localized character but the shifted char is a Latin alphabet,
+      // then, we should not execute without the shift state. See bug 433192.
+      if (IsCaseChangeableChar(ch)) {
+        continue;
+      }
+
+      // Setting the alternative charCode candidates for retry without shift
+      // key state only when the shift key is pressed.
+      ShortcutKeyCandidate key(ch, ShiftState::Ignorable,
+                               SkipIfEarlierHandlerDisabled::No);
+      aCandidates.AppendElement(key);
+    }
+  }
+
+  // Special case for "Space" key.  With some keyboard layouts, "Space" with
+  // or without Shift key causes non-ASCII space.  For such keyboard layouts,
+  // we should guarantee that the key press works as an ASCII white space key
+  // press.  However, if the space key is assigned to a function key, it
+  // shouldn't work as a space key.
+  if (mKeyNameIndex == KEY_NAME_INDEX_USE_STRING &&
+      mCodeNameIndex == CODE_NAME_INDEX_Space && pseudoCharCode != ' ') {
+    ShortcutKeyCandidate spaceKey(' ', ShiftState::MatchExactly,
+                                  SkipIfEarlierHandlerDisabled::No);
+    aCandidates.AppendElement(spaceKey);
+  }
+}
+
+void WidgetKeyboardEvent::GetAccessKeyCandidates(
+    nsTArray<uint32_t>& aCandidates) const {
+  MOZ_ASSERT(aCandidates.IsEmpty(), "aCandidates must be empty");
+
+  // return the lower cased charCode candidates for access keys.
+  // the priority of the charCodes are:
+  //   0: charCode, 1: unshiftedCharCodes[0], 2: shiftedCharCodes[0]
+  //   3: unshiftedCharCodes[1], 4: shiftedCharCodes[1],...
+  uint32_t pseudoCharCode = PseudoCharCode();
+  if (pseudoCharCode) {
+    uint32_t ch = pseudoCharCode;
+    if (IS_IN_BMP(ch)) {
+      ch = ToLowerCase(static_cast<char16_t>(ch));
+    }
+    aCandidates.AppendElement(ch);
+  }
+  for (uint32_t i = 0; i < mAlternativeCharCodes.Length(); ++i) {
+    uint32_t ch[2] = {mAlternativeCharCodes[i].mUnshiftedCharCode,
+                      mAlternativeCharCodes[i].mShiftedCharCode};
+    for (uint32_t j = 0; j < 2; ++j) {
+      if (!ch[j]) {
+        continue;
+      }
+      if (IS_IN_BMP(ch[j])) {
+        ch[j] = ToLowerCase(static_cast<char16_t>(ch[j]));
+      }
+      // Don't append the charcode that was already appended.
+      if (aCandidates.IndexOf(ch[j]) == aCandidates.NoIndex) {
+        aCandidates.AppendElement(ch[j]);
+      }
+    }
+  }
+  // Special case for "Space" key.  With some keyboard layouts, "Space" with
+  // or without Shift key causes non-ASCII space.  For such keyboard layouts,
+  // we should guarantee that the key press works as an ASCII white space key
+  // press.  However, if the space key is assigned to a function key, it
+  // shouldn't work as a space key.
+  if (mKeyNameIndex == KEY_NAME_INDEX_USE_STRING &&
+      mCodeNameIndex == CODE_NAME_INDEX_Space && pseudoCharCode != ' ') {
+    aCandidates.AppendElement(' ');
+  }
+}
+
+// mask values for ui.key.chromeAccess and ui.key.contentAccess
+#define NS_MODIFIER_SHIFT 1
+#define NS_MODIFIER_CONTROL 2
+#define NS_MODIFIER_ALT 4
+#define NS_MODIFIER_META 8
+
+static Modifiers PrefFlagsToModifiers(int32_t aPrefFlags) {
+  Modifiers result = 0;
+  if (aPrefFlags & NS_MODIFIER_SHIFT) {
+    result |= MODIFIER_SHIFT;
+  }
+  if (aPrefFlags & NS_MODIFIER_CONTROL) {
+    result |= MODIFIER_CONTROL;
+  }
+  if (aPrefFlags & NS_MODIFIER_ALT) {
+    result |= MODIFIER_ALT;
+  }
+  if (aPrefFlags & NS_MODIFIER_META) {
+    result |= MODIFIER_META;
+  }
+  return result;
+}
+
+bool WidgetKeyboardEvent::ModifiersMatchWithAccessKey(
+    AccessKeyType aType) const {
+  if (!ModifiersForAccessKeyMatching()) {
+    return false;
+  }
+  return ModifiersForAccessKeyMatching() == AccessKeyModifiers(aType);
+}
+
+Modifiers WidgetKeyboardEvent::ModifiersForAccessKeyMatching() const {
+  static const Modifiers kModifierMask =
+      MODIFIER_SHIFT | MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META;
+  return mModifiers & kModifierMask;
+}
+
+/* static */
+Modifiers WidgetKeyboardEvent::AccessKeyModifiers(AccessKeyType aType) {
+  switch (StaticPrefs::ui_key_generalAccessKey()) {
+    case -1:
+      break;  // use the individual prefs
+    case NS_VK_SHIFT:
+      return MODIFIER_SHIFT;
+    case NS_VK_CONTROL:
+      return MODIFIER_CONTROL;
+    case NS_VK_ALT:
+      return MODIFIER_ALT;
+    case NS_VK_META:
+    case NS_VK_WIN:
+      return MODIFIER_META;
+    default:
+      return MODIFIER_NONE;
+  }
+
+  switch (aType) {
+    case AccessKeyType::eChrome:
+      return PrefFlagsToModifiers(StaticPrefs::ui_key_chromeAccess());
+    case AccessKeyType::eContent:
+      return PrefFlagsToModifiers(StaticPrefs::ui_key_contentAccess());
+    default:
+      return MODIFIER_NONE;
+  }
+}
+
+/* static */
+void WidgetKeyboardEvent::Shutdown() {
+  delete sKeyNameIndexHashtable;
+  sKeyNameIndexHashtable = nullptr;
+  delete sCodeNameIndexHashtable;
+  sCodeNameIndexHashtable = nullptr;
+  // Although sCommandHashtable is not a member of WidgetKeyboardEvent, but
+  // let's delete it here since we need to do it at same time.
+  delete sCommandHashtable;
+  sCommandHashtable = nullptr;
+}
+
+/* static */
+void WidgetKeyboardEvent::GetDOMKeyName(KeyNameIndex aKeyNameIndex,
+                                        nsAString& aKeyName) {
+  if (aKeyNameIndex >= KEY_NAME_INDEX_USE_STRING) {
+    aKeyName.Truncate();
+    return;
+  }
+
+  MOZ_RELEASE_ASSERT(
+      static_cast<size_t>(aKeyNameIndex) < ArrayLength(kKeyNames),
+      "Illegal key enumeration value");
+  aKeyName = kKeyNames[aKeyNameIndex];
+}
+
+/* static */
+void WidgetKeyboardEvent::GetDOMCodeName(CodeNameIndex aCodeNameIndex,
+                                         nsAString& aCodeName) {
+  if (aCodeNameIndex >= CODE_NAME_INDEX_USE_STRING) {
+    aCodeName.Truncate();
+    return;
+  }
+
+  MOZ_RELEASE_ASSERT(
+      static_cast<size_t>(aCodeNameIndex) < ArrayLength(kCodeNames),
+      "Illegal physical code enumeration value");
+
+  // Generate some continuous runs of codes, rather than looking them up.
+  if (aCodeNameIndex >= CODE_NAME_INDEX_KeyA &&
+      aCodeNameIndex <= CODE_NAME_INDEX_KeyZ) {
+    uint32_t index = aCodeNameIndex - CODE_NAME_INDEX_KeyA;
+    aCodeName.AssignLiteral(u"Key");
+    aCodeName.Append(u'A' + index);
+    return;
+  }
+  if (aCodeNameIndex >= CODE_NAME_INDEX_Digit0 &&
+      aCodeNameIndex <= CODE_NAME_INDEX_Digit9) {
+    uint32_t index = aCodeNameIndex - CODE_NAME_INDEX_Digit0;
+    aCodeName.AssignLiteral(u"Digit");
+    aCodeName.AppendInt(index);
+    return;
+  }
+  if (aCodeNameIndex >= CODE_NAME_INDEX_Numpad0 &&
+      aCodeNameIndex <= CODE_NAME_INDEX_Numpad9) {
+    uint32_t index = aCodeNameIndex - CODE_NAME_INDEX_Numpad0;
+    aCodeName.AssignLiteral(u"Numpad");
+    aCodeName.AppendInt(index);
+    return;
+  }
+  if (aCodeNameIndex >= CODE_NAME_INDEX_F1 &&
+      aCodeNameIndex <= CODE_NAME_INDEX_F24) {
+    uint32_t index = aCodeNameIndex - CODE_NAME_INDEX_F1;
+    aCodeName.Assign(u'F');
+    aCodeName.AppendInt(index + 1);
+    return;
+  }
+
+  aCodeName = kCodeNames[aCodeNameIndex];
+}
+
+/* static */
+KeyNameIndex WidgetKeyboardEvent::GetKeyNameIndex(const nsAString& aKeyValue) {
+  if (!sKeyNameIndexHashtable) {
+    sKeyNameIndexHashtable = new KeyNameIndexHashtable(ArrayLength(kKeyNames));
+    for (size_t i = 0; i < ArrayLength(kKeyNames); i++) {
+      sKeyNameIndexHashtable->InsertOrUpdate(nsDependentString(kKeyNames[i]),
+                                             static_cast<KeyNameIndex>(i));
+    }
+  }
+  return sKeyNameIndexHashtable->MaybeGet(aKeyValue).valueOr(
+      KEY_NAME_INDEX_USE_STRING);
+}
+
+/* static */
+CodeNameIndex WidgetKeyboardEvent::GetCodeNameIndex(
+    const nsAString& aCodeValue) {
+  if (!sCodeNameIndexHashtable) {
+    sCodeNameIndexHashtable =
+        new CodeNameIndexHashtable(ArrayLength(kCodeNames));
+    for (size_t i = 0; i < ArrayLength(kCodeNames); i++) {
+      sCodeNameIndexHashtable->InsertOrUpdate(nsDependentString(kCodeNames[i]),
+                                              static_cast<CodeNameIndex>(i));
+    }
+  }
+  return sCodeNameIndexHashtable->MaybeGet(aCodeValue)
+      .valueOr(CODE_NAME_INDEX_USE_STRING);
+}
+
+/* static */
+uint32_t WidgetKeyboardEvent::GetFallbackKeyCodeOfPunctuationKey(
+    CodeNameIndex aCodeNameIndex) {
+  switch (aCodeNameIndex) {
+    case CODE_NAME_INDEX_Semicolon:  // VK_OEM_1 on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_SEMICOLON;
+    case CODE_NAME_INDEX_Equal:  // VK_OEM_PLUS on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_EQUALS;
+    case CODE_NAME_INDEX_Comma:  // VK_OEM_COMMA on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_COMMA;
+    case CODE_NAME_INDEX_Minus:  // VK_OEM_MINUS on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_HYPHEN_MINUS;
+    case CODE_NAME_INDEX_Period:  // VK_OEM_PERIOD on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_PERIOD;
+    case CODE_NAME_INDEX_Slash:  // VK_OEM_2 on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_SLASH;
+    case CODE_NAME_INDEX_Backquote:  // VK_OEM_3 on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_BACK_QUOTE;
+    case CODE_NAME_INDEX_BracketLeft:  // VK_OEM_4 on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_OPEN_BRACKET;
+    case CODE_NAME_INDEX_Backslash:  // VK_OEM_5 on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_BACK_SLASH;
+    case CODE_NAME_INDEX_BracketRight:  // VK_OEM_6 on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_CLOSE_BRACKET;
+    case CODE_NAME_INDEX_Quote:  // VK_OEM_7 on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_QUOTE;
+    case CODE_NAME_INDEX_IntlBackslash:  // VK_OEM_5 on Windows (ABNT, etc)
+    case CODE_NAME_INDEX_IntlYen:        // VK_OEM_5 on Windows (JIS)
+    case CODE_NAME_INDEX_IntlRo:         // VK_OEM_102 on Windows
+      return dom::KeyboardEvent_Binding::DOM_VK_BACK_SLASH;
+    default:
+      return 0;
+  }
+}
+
+/* static */ const char* WidgetKeyboardEvent::GetCommandStr(Command aCommand) {
+#define NS_DEFINE_COMMAND(aName, aCommandStr) , #aCommandStr
+#define NS_DEFINE_COMMAND_WITH_PARAM(aName, aCommandStr, aParam) , #aCommandStr
+#define NS_DEFINE_COMMAND_NO_EXEC_COMMAND(aName) , ""
+  static const char* const kCommands[] = {
+      ""  // DoNothing
+#include "mozilla/CommandList.h"
+  };
+#undef NS_DEFINE_COMMAND
+#undef NS_DEFINE_COMMAND_WITH_PARAM
+#undef NS_DEFINE_COMMAND_NO_EXEC_COMMAND
+
+  MOZ_RELEASE_ASSERT(static_cast<size_t>(aCommand) < ArrayLength(kCommands),
+                     "Illegal command enumeration value");
+  return kCommands[static_cast<CommandInt>(aCommand)];
+}
+
+/* static */
+uint32_t WidgetKeyboardEvent::ComputeLocationFromCodeValue(
+    CodeNameIndex aCodeNameIndex) {
+  // Following commented out cases are not defined in PhysicalKeyCodeNameList.h
+  // but are defined by D3E spec.  So, they should be uncommented when the
+  // code values are defined in the header.
+  switch (aCodeNameIndex) {
+    case CODE_NAME_INDEX_AltLeft:
+    case CODE_NAME_INDEX_ControlLeft:
+    case CODE_NAME_INDEX_MetaLeft:
+    case CODE_NAME_INDEX_ShiftLeft:
+      return eKeyLocationLeft;
+    case CODE_NAME_INDEX_AltRight:
+    case CODE_NAME_INDEX_ControlRight:
+    case CODE_NAME_INDEX_MetaRight:
+    case CODE_NAME_INDEX_ShiftRight:
+      return eKeyLocationRight;
+    case CODE_NAME_INDEX_Numpad0:
+    case CODE_NAME_INDEX_Numpad1:
+    case CODE_NAME_INDEX_Numpad2:
+    case CODE_NAME_INDEX_Numpad3:
+    case CODE_NAME_INDEX_Numpad4:
+    case CODE_NAME_INDEX_Numpad5:
+    case CODE_NAME_INDEX_Numpad6:
+    case CODE_NAME_INDEX_Numpad7:
+    case CODE_NAME_INDEX_Numpad8:
+    case CODE_NAME_INDEX_Numpad9:
+    case CODE_NAME_INDEX_NumpadAdd:
+    case CODE_NAME_INDEX_NumpadBackspace:
+    case CODE_NAME_INDEX_NumpadClear:
+    case CODE_NAME_INDEX_NumpadClearEntry:
+    case CODE_NAME_INDEX_NumpadComma:
+    case CODE_NAME_INDEX_NumpadDecimal:
+    case CODE_NAME_INDEX_NumpadDivide:
+    case CODE_NAME_INDEX_NumpadEnter:
+    case CODE_NAME_INDEX_NumpadEqual:
+    case CODE_NAME_INDEX_NumpadMemoryAdd:
+    case CODE_NAME_INDEX_NumpadMemoryClear:
+    case CODE_NAME_INDEX_NumpadMemoryRecall:
+    case CODE_NAME_INDEX_NumpadMemoryStore:
+    case CODE_NAME_INDEX_NumpadMemorySubtract:
+    case CODE_NAME_INDEX_NumpadMultiply:
+    case CODE_NAME_INDEX_NumpadParenLeft:
+    case CODE_NAME_INDEX_NumpadParenRight:
+    case CODE_NAME_INDEX_NumpadSubtract:
+      return eKeyLocationNumpad;
+    default:
+      return eKeyLocationStandard;
+  }
+}
+
+/* static */
+uint32_t WidgetKeyboardEvent::ComputeKeyCodeFromKeyNameIndex(
+    KeyNameIndex aKeyNameIndex) {
+  switch (aKeyNameIndex) {
+    case KEY_NAME_INDEX_Cancel:
+      return dom::KeyboardEvent_Binding::DOM_VK_CANCEL;
+    case KEY_NAME_INDEX_Help:
+      return dom::KeyboardEvent_Binding::DOM_VK_HELP;
+    case KEY_NAME_INDEX_Backspace:
+      return dom::KeyboardEvent_Binding::DOM_VK_BACK_SPACE;
+    case KEY_NAME_INDEX_Tab:
+      return dom::KeyboardEvent_Binding::DOM_VK_TAB;
+    case KEY_NAME_INDEX_Clear:
+      return dom::KeyboardEvent_Binding::DOM_VK_CLEAR;
+    case KEY_NAME_INDEX_Enter:
+      return dom::KeyboardEvent_Binding::DOM_VK_RETURN;
+    case KEY_NAME_INDEX_Shift:
+      return dom::KeyboardEvent_Binding::DOM_VK_SHIFT;
+    case KEY_NAME_INDEX_Control:
+      return dom::KeyboardEvent_Binding::DOM_VK_CONTROL;
+    case KEY_NAME_INDEX_Alt:
+      return dom::KeyboardEvent_Binding::DOM_VK_ALT;
+    case KEY_NAME_INDEX_Pause:
+      return dom::KeyboardEvent_Binding::DOM_VK_PAUSE;
+    case KEY_NAME_INDEX_CapsLock:
+      return dom::KeyboardEvent_Binding::DOM_VK_CAPS_LOCK;
+    case KEY_NAME_INDEX_Hiragana:
+    case KEY_NAME_INDEX_Katakana:
+    case KEY_NAME_INDEX_HiraganaKatakana:
+    case KEY_NAME_INDEX_KanaMode:
+      return dom::KeyboardEvent_Binding::DOM_VK_KANA;
+    case KEY_NAME_INDEX_HangulMode:
+      return dom::KeyboardEvent_Binding::DOM_VK_HANGUL;
+    case KEY_NAME_INDEX_Eisu:
+      return dom::KeyboardEvent_Binding::DOM_VK_EISU;
+    case KEY_NAME_INDEX_JunjaMode:
+      return dom::KeyboardEvent_Binding::DOM_VK_JUNJA;
+    case KEY_NAME_INDEX_FinalMode:
+      return dom::KeyboardEvent_Binding::DOM_VK_FINAL;
+    case KEY_NAME_INDEX_HanjaMode:
+      return dom::KeyboardEvent_Binding::DOM_VK_HANJA;
+    case KEY_NAME_INDEX_KanjiMode:
+      return dom::KeyboardEvent_Binding::DOM_VK_KANJI;
+    case KEY_NAME_INDEX_Escape:
+      return dom::KeyboardEvent_Binding::DOM_VK_ESCAPE;
+    case KEY_NAME_INDEX_Convert:
+      return dom::KeyboardEvent_Binding::DOM_VK_CONVERT;
+    case KEY_NAME_INDEX_NonConvert:
+      return dom::KeyboardEvent_Binding::DOM_VK_NONCONVERT;
+    case KEY_NAME_INDEX_Accept:
+      return dom::KeyboardEvent_Binding::DOM_VK_ACCEPT;
+    case KEY_NAME_INDEX_ModeChange:
+      return dom::KeyboardEvent_Binding::DOM_VK_MODECHANGE;
+    case KEY_NAME_INDEX_PageUp:
+      return dom::KeyboardEvent_Binding::DOM_VK_PAGE_UP;
+    case KEY_NAME_INDEX_PageDown:
+      return dom::KeyboardEvent_Binding::DOM_VK_PAGE_DOWN;
+    case KEY_NAME_INDEX_End:
+      return dom::KeyboardEvent_Binding::DOM_VK_END;
+    case KEY_NAME_INDEX_Home:
+      return dom::KeyboardEvent_Binding::DOM_VK_HOME;
+    case KEY_NAME_INDEX_ArrowLeft:
+      return dom::KeyboardEvent_Binding::DOM_VK_LEFT;
+    case KEY_NAME_INDEX_ArrowUp:
+      return dom::KeyboardEvent_Binding::DOM_VK_UP;
+    case KEY_NAME_INDEX_ArrowRight:
+      return dom::KeyboardEvent_Binding::DOM_VK_RIGHT;
+    case KEY_NAME_INDEX_ArrowDown:
+      return dom::KeyboardEvent_Binding::DOM_VK_DOWN;
+    case KEY_NAME_INDEX_Select:
+      return dom::KeyboardEvent_Binding::DOM_VK_SELECT;
+    case KEY_NAME_INDEX_Print:
+      return dom::KeyboardEvent_Binding::DOM_VK_PRINT;
+    case KEY_NAME_INDEX_Execute:
+      return dom::KeyboardEvent_Binding::DOM_VK_EXECUTE;
+    case KEY_NAME_INDEX_PrintScreen:
+      return dom::KeyboardEvent_Binding::DOM_VK_PRINTSCREEN;
+    case KEY_NAME_INDEX_Insert:
+      return dom::KeyboardEvent_Binding::DOM_VK_INSERT;
+    case KEY_NAME_INDEX_Delete:
+      return dom::KeyboardEvent_Binding::DOM_VK_DELETE;
+    case KEY_NAME_INDEX_ContextMenu:
+      return dom::KeyboardEvent_Binding::DOM_VK_CONTEXT_MENU;
+    case KEY_NAME_INDEX_Standby:
+      return dom::KeyboardEvent_Binding::DOM_VK_SLEEP;
+    case KEY_NAME_INDEX_F1:
+      return dom::KeyboardEvent_Binding::DOM_VK_F1;
+    case KEY_NAME_INDEX_F2:
+      return dom::KeyboardEvent_Binding::DOM_VK_F2;
+    case KEY_NAME_INDEX_F3:
+      return dom::KeyboardEvent_Binding::DOM_VK_F3;
+    case KEY_NAME_INDEX_F4:
+      return dom::KeyboardEvent_Binding::DOM_VK_F4;
+    case KEY_NAME_INDEX_F5:
+      return dom::KeyboardEvent_Binding::DOM_VK_F5;
+    case KEY_NAME_INDEX_F6:
+      return dom::KeyboardEvent_Binding::DOM_VK_F6;
+    case KEY_NAME_INDEX_F7:
+      return dom::KeyboardEvent_Binding::DOM_VK_F7;
+    case KEY_NAME_INDEX_F8:
+      return dom::KeyboardEvent_Binding::DOM_VK_F8;
+    case KEY_NAME_INDEX_F9:
+      return dom::KeyboardEvent_Binding::DOM_VK_F9;
+    case KEY_NAME_INDEX_F10:
+      return dom::KeyboardEvent_Binding::DOM_VK_F10;
+    case KEY_NAME_INDEX_F11:
+      return dom::KeyboardEvent_Binding::DOM_VK_F11;
+    case KEY_NAME_INDEX_F12:
+      return dom::KeyboardEvent_Binding::DOM_VK_F12;
+    case KEY_NAME_INDEX_F13:
+      return dom::KeyboardEvent_Binding::DOM_VK_F13;
+    case KEY_NAME_INDEX_F14:
+      return dom::KeyboardEvent_Binding::DOM_VK_F14;
+    case KEY_NAME_INDEX_F15:
+      return dom::KeyboardEvent_Binding::DOM_VK_F15;
+    case KEY_NAME_INDEX_F16:
+      return dom::KeyboardEvent_Binding::DOM_VK_F16;
+    case KEY_NAME_INDEX_F17:
+      return dom::KeyboardEvent_Binding::DOM_VK_F17;
+    case KEY_NAME_INDEX_F18:
+      return dom::KeyboardEvent_Binding::DOM_VK_F18;
+    case KEY_NAME_INDEX_F19:
+      return dom::KeyboardEvent_Binding::DOM_VK_F19;
+    case KEY_NAME_INDEX_F20:
+      return dom::KeyboardEvent_Binding::DOM_VK_F20;
+    case KEY_NAME_INDEX_F21:
+      return dom::KeyboardEvent_Binding::DOM_VK_F21;
+    case KEY_NAME_INDEX_F22:
+      return dom::KeyboardEvent_Binding::DOM_VK_F22;
+    case KEY_NAME_INDEX_F23:
+      return dom::KeyboardEvent_Binding::DOM_VK_F23;
+    case KEY_NAME_INDEX_F24:
+      return dom::KeyboardEvent_Binding::DOM_VK_F24;
+    case KEY_NAME_INDEX_NumLock:
+      return dom::KeyboardEvent_Binding::DOM_VK_NUM_LOCK;
+    case KEY_NAME_INDEX_ScrollLock:
+      return dom::KeyboardEvent_Binding::DOM_VK_SCROLL_LOCK;
+    case KEY_NAME_INDEX_AudioVolumeMute:
+      return dom::KeyboardEvent_Binding::DOM_VK_VOLUME_MUTE;
+    case KEY_NAME_INDEX_AudioVolumeDown:
+      return dom::KeyboardEvent_Binding::DOM_VK_VOLUME_DOWN;
+    case KEY_NAME_INDEX_AudioVolumeUp:
+      return dom::KeyboardEvent_Binding::DOM_VK_VOLUME_UP;
+    case KEY_NAME_INDEX_Meta:
+#if defined(XP_WIN) || defined(MOZ_WIDGET_GTK)
+      return dom::KeyboardEvent_Binding::DOM_VK_WIN;
+#else
+      return dom::KeyboardEvent_Binding::DOM_VK_META;
+#endif
+    case KEY_NAME_INDEX_AltGraph:
+      return dom::KeyboardEvent_Binding::DOM_VK_ALTGR;
+    case KEY_NAME_INDEX_Process:
+      return dom::KeyboardEvent_Binding::DOM_VK_PROCESSKEY;
+    case KEY_NAME_INDEX_Attn:
+      return dom::KeyboardEvent_Binding::DOM_VK_ATTN;
+    case KEY_NAME_INDEX_CrSel:
+      return dom::KeyboardEvent_Binding::DOM_VK_CRSEL;
+    case KEY_NAME_INDEX_ExSel:
+      return dom::KeyboardEvent_Binding::DOM_VK_EXSEL;
+    case KEY_NAME_INDEX_EraseEof:
+      return dom::KeyboardEvent_Binding::DOM_VK_EREOF;
+    case KEY_NAME_INDEX_Play:
+      return dom::KeyboardEvent_Binding::DOM_VK_PLAY;
+    case KEY_NAME_INDEX_ZoomToggle:
+    case KEY_NAME_INDEX_ZoomIn:
+    case KEY_NAME_INDEX_ZoomOut:
+      return dom::KeyboardEvent_Binding::DOM_VK_ZOOM;
+    default:
+      return 0;
+  }
+}
+
+/* static */
+CodeNameIndex WidgetKeyboardEvent::ComputeCodeNameIndexFromKeyNameIndex(
+    KeyNameIndex aKeyNameIndex, const Maybe<uint32_t>& aLocation) {
+  if (aLocation.isSome() &&
+      aLocation.value() ==
+          dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_NUMPAD) {
+    // On macOS, NumLock is not supported.  Therefore, this handles
+    // control key values except "Enter" only on non-macOS platforms.
+    switch (aKeyNameIndex) {
+#ifndef XP_MACOSX
+      case KEY_NAME_INDEX_Insert:
+        return CODE_NAME_INDEX_Numpad0;
+      case KEY_NAME_INDEX_End:
+        return CODE_NAME_INDEX_Numpad1;
+      case KEY_NAME_INDEX_ArrowDown:
+        return CODE_NAME_INDEX_Numpad2;
+      case KEY_NAME_INDEX_PageDown:
+        return CODE_NAME_INDEX_Numpad3;
+      case KEY_NAME_INDEX_ArrowLeft:
+        return CODE_NAME_INDEX_Numpad4;
+      case KEY_NAME_INDEX_Clear:
+        // FYI: "Clear" on macOS should be DOM_KEY_LOCATION_STANDARD.
+        return CODE_NAME_INDEX_Numpad5;
+      case KEY_NAME_INDEX_ArrowRight:
+        return CODE_NAME_INDEX_Numpad6;
+      case KEY_NAME_INDEX_Home:
+        return CODE_NAME_INDEX_Numpad7;
+      case KEY_NAME_INDEX_ArrowUp:
+        return CODE_NAME_INDEX_Numpad8;
+      case KEY_NAME_INDEX_PageUp:
+        return CODE_NAME_INDEX_Numpad9;
+      case KEY_NAME_INDEX_Delete:
+        return CODE_NAME_INDEX_NumpadDecimal;
+#endif  // #ifndef XP_MACOSX
+      case KEY_NAME_INDEX_Enter:
+        return CODE_NAME_INDEX_NumpadEnter;
+      default:
+        return CODE_NAME_INDEX_UNKNOWN;
+    }
+  }
+
+  if (WidgetKeyboardEvent::IsLeftOrRightModiferKeyNameIndex(aKeyNameIndex)) {
+    if (aLocation.isSome() &&
+        (aLocation.value() !=
+             dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_LEFT &&
+         aLocation.value() !=
+             dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_RIGHT)) {
+      return CODE_NAME_INDEX_UNKNOWN;
+    }
+    bool isRight =
+        aLocation.isSome() &&
+        aLocation.value() == dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_RIGHT;
+    switch (aKeyNameIndex) {
+      case KEY_NAME_INDEX_Alt:
+        return isRight ? CODE_NAME_INDEX_AltRight : CODE_NAME_INDEX_AltLeft;
+      case KEY_NAME_INDEX_Control:
+        return isRight ? CODE_NAME_INDEX_ControlRight
+                       : CODE_NAME_INDEX_ControlLeft;
+      case KEY_NAME_INDEX_Shift:
+        return isRight ? CODE_NAME_INDEX_ShiftRight : CODE_NAME_INDEX_ShiftLeft;
+      case KEY_NAME_INDEX_Meta:
+        return isRight ? CODE_NAME_INDEX_MetaRight : CODE_NAME_INDEX_MetaLeft;
+      default:
+        return CODE_NAME_INDEX_UNKNOWN;
+    }
+  }
+
+  if (aLocation.isSome() &&
+      aLocation.value() !=
+          dom::KeyboardEvent_Binding::DOM_KEY_LOCATION_STANDARD) {
+    return CODE_NAME_INDEX_UNKNOWN;
+  }
+
+  switch (aKeyNameIndex) {
+    // Standard section:
+    case KEY_NAME_INDEX_Escape:
+      return CODE_NAME_INDEX_Escape;
+    case KEY_NAME_INDEX_Tab:
+      return CODE_NAME_INDEX_Tab;
+    case KEY_NAME_INDEX_CapsLock:
+      return CODE_NAME_INDEX_CapsLock;
+    case KEY_NAME_INDEX_ContextMenu:
+      return CODE_NAME_INDEX_ContextMenu;
+    case KEY_NAME_INDEX_Backspace:
+      return CODE_NAME_INDEX_Backspace;
+    case KEY_NAME_INDEX_Enter:
+      return CODE_NAME_INDEX_Enter;
+#ifdef XP_MACOSX
+    // Although, macOS does not fire native key event of "Fn" key, we support
+    // Fn key event if it's sent by other apps directly.
+    case KEY_NAME_INDEX_Fn:
+      return CODE_NAME_INDEX_Fn;
+#endif  // #ifdef
+
+    // Arrow Pad section:
+    case KEY_NAME_INDEX_ArrowLeft:
+      return CODE_NAME_INDEX_ArrowLeft;
+    case KEY_NAME_INDEX_ArrowUp:
+      return CODE_NAME_INDEX_ArrowUp;
+    case KEY_NAME_INDEX_ArrowDown:
+      return CODE_NAME_INDEX_ArrowDown;
+    case KEY_NAME_INDEX_ArrowRight:
+      return CODE_NAME_INDEX_ArrowRight;
+
+      // Control Pad section:
+#ifndef XP_MACOSX
+    case KEY_NAME_INDEX_Insert:
+      return CODE_NAME_INDEX_Insert;
+#else
+    case KEY_NAME_INDEX_Help:
+      return CODE_NAME_INDEX_Help;
+#endif  // #ifndef XP_MACOSX #else
+    case KEY_NAME_INDEX_Delete:
+      return CODE_NAME_INDEX_Delete;
+    case KEY_NAME_INDEX_Home:
+      return CODE_NAME_INDEX_Home;
+    case KEY_NAME_INDEX_End:
+      return CODE_NAME_INDEX_End;
+    case KEY_NAME_INDEX_PageUp:
+      return CODE_NAME_INDEX_PageUp;
+    case KEY_NAME_INDEX_PageDown:
+      return CODE_NAME_INDEX_PageDown;
+
+    // Function keys:
+    case KEY_NAME_INDEX_F1:
+      return CODE_NAME_INDEX_F1;
+    case KEY_NAME_INDEX_F2:
+      return CODE_NAME_INDEX_F2;
+    case KEY_NAME_INDEX_F3:
+      return CODE_NAME_INDEX_F3;
+    case KEY_NAME_INDEX_F4:
+      return CODE_NAME_INDEX_F4;
+    case KEY_NAME_INDEX_F5:
+      return CODE_NAME_INDEX_F5;
+    case KEY_NAME_INDEX_F6:
+      return CODE_NAME_INDEX_F6;
+    case KEY_NAME_INDEX_F7:
+      return CODE_NAME_INDEX_F7;
+    case KEY_NAME_INDEX_F8:
+      return CODE_NAME_INDEX_F8;
+    case KEY_NAME_INDEX_F9:
+      return CODE_NAME_INDEX_F9;
+    case KEY_NAME_INDEX_F10:
+      return CODE_NAME_INDEX_F10;
+    case KEY_NAME_INDEX_F11:
+      return CODE_NAME_INDEX_F11;
+    case KEY_NAME_INDEX_F12:
+      return CODE_NAME_INDEX_F12;
+    case KEY_NAME_INDEX_F13:
+      return CODE_NAME_INDEX_F13;
+    case KEY_NAME_INDEX_F14:
+      return CODE_NAME_INDEX_F14;
+    case KEY_NAME_INDEX_F15:
+      return CODE_NAME_INDEX_F15;
+    case KEY_NAME_INDEX_F16:
+      return CODE_NAME_INDEX_F16;
+    case KEY_NAME_INDEX_F17:
+      return CODE_NAME_INDEX_F17;
+    case KEY_NAME_INDEX_F18:
+      return CODE_NAME_INDEX_F18;
+    case KEY_NAME_INDEX_F19:
+      return CODE_NAME_INDEX_F19;
+    case KEY_NAME_INDEX_F20:
+      return CODE_NAME_INDEX_F20;
+#ifndef XP_MACOSX
+    case KEY_NAME_INDEX_F21:
+      return CODE_NAME_INDEX_F21;
+    case KEY_NAME_INDEX_F22:
+      return CODE_NAME_INDEX_F22;
+    case KEY_NAME_INDEX_F23:
+      return CODE_NAME_INDEX_F23;
+    case KEY_NAME_INDEX_F24:
+      return CODE_NAME_INDEX_F24;
+    case KEY_NAME_INDEX_Pause:
+      return CODE_NAME_INDEX_Pause;
+    case KEY_NAME_INDEX_PrintScreen:
+      return CODE_NAME_INDEX_PrintScreen;
+    case KEY_NAME_INDEX_ScrollLock:
+      return CODE_NAME_INDEX_ScrollLock;
+#endif  // #ifndef XP_MACOSX
+
+      // NumLock key:
+#ifndef XP_MACOSX
+    case KEY_NAME_INDEX_NumLock:
+      return CODE_NAME_INDEX_NumLock;
+#else
+    case KEY_NAME_INDEX_Clear:
+      return CODE_NAME_INDEX_NumLock;
+#endif  // #ifndef XP_MACOSX #else
+
+    // Media keys:
+    case KEY_NAME_INDEX_AudioVolumeDown:
+      return CODE_NAME_INDEX_VolumeDown;
+    case KEY_NAME_INDEX_AudioVolumeMute:
+      return CODE_NAME_INDEX_VolumeMute;
+    case KEY_NAME_INDEX_AudioVolumeUp:
+      return CODE_NAME_INDEX_VolumeUp;
+#ifndef XP_MACOSX
+    case KEY_NAME_INDEX_BrowserBack:
+      return CODE_NAME_INDEX_BrowserBack;
+    case KEY_NAME_INDEX_BrowserFavorites:
+      return CODE_NAME_INDEX_BrowserFavorites;
+    case KEY_NAME_INDEX_BrowserForward:
+      return CODE_NAME_INDEX_BrowserForward;
+    case KEY_NAME_INDEX_BrowserRefresh:
+      return CODE_NAME_INDEX_BrowserRefresh;
+    case KEY_NAME_INDEX_BrowserSearch:
+      return CODE_NAME_INDEX_BrowserSearch;
+    case KEY_NAME_INDEX_BrowserStop:
+      return CODE_NAME_INDEX_BrowserStop;
+    case KEY_NAME_INDEX_MediaPlayPause:
+      return CODE_NAME_INDEX_MediaPlayPause;
+    case KEY_NAME_INDEX_MediaStop:
+      return CODE_NAME_INDEX_MediaStop;
+    case KEY_NAME_INDEX_MediaTrackNext:
+      return CODE_NAME_INDEX_MediaTrackNext;
+    case KEY_NAME_INDEX_MediaTrackPrevious:
+      return CODE_NAME_INDEX_MediaTrackPrevious;
+    case KEY_NAME_INDEX_LaunchApplication1:
+      return CODE_NAME_INDEX_LaunchApp1;
+#endif  // #ifndef XP_MACOSX
+
+      // Only Windows and GTK supports the following multimedia keys.
+#if defined(XP_WIN) || defined(MOZ_WIDGET_GTK)
+    case KEY_NAME_INDEX_BrowserHome:
+      return CODE_NAME_INDEX_BrowserHome;
+    case KEY_NAME_INDEX_LaunchApplication2:
+      return CODE_NAME_INDEX_LaunchApp2;
+#endif  // #if defined(XP_WIN) || defined(MOZ_WIDGET_GTK)
+
+      // Only GTK and Android supports the following multimedia keys.
+#if defined(MOZ_WIDGET_GTK) || defined(ANDROID)
+    case KEY_NAME_INDEX_Eject:
+      return CODE_NAME_INDEX_Eject;
+    case KEY_NAME_INDEX_WakeUp:
+      return CODE_NAME_INDEX_WakeUp;
+#endif  // #if defined(MOZ_WIDGET_GTK) || defined(ANDROID)
+
+      // Only Windows does not support Help key (and macOS handled above).
+#if !defined(XP_WIN) && !defined(XP_MACOSX)
+    case KEY_NAME_INDEX_Help:
+      return CODE_NAME_INDEX_Help;
+#endif  // #if !defined(XP_WIN) && !defined(XP_MACOSX)
+
+      // IME specific keys:
+#ifdef XP_WIN
+    case KEY_NAME_INDEX_Convert:
+      return CODE_NAME_INDEX_Convert;
+    case KEY_NAME_INDEX_NonConvert:
+      return CODE_NAME_INDEX_NonConvert;
+    case KEY_NAME_INDEX_Alphanumeric:
+      return CODE_NAME_INDEX_CapsLock;
+    case KEY_NAME_INDEX_KanaMode:
+    case KEY_NAME_INDEX_Romaji:
+    case KEY_NAME_INDEX_Katakana:
+    case KEY_NAME_INDEX_Hiragana:
+      return CODE_NAME_INDEX_KanaMode;
+    case KEY_NAME_INDEX_Hankaku:
+    case KEY_NAME_INDEX_Zenkaku:
+    case KEY_NAME_INDEX_KanjiMode:
+      return CODE_NAME_INDEX_Backquote;
+    case KEY_NAME_INDEX_HanjaMode:
+      return CODE_NAME_INDEX_Lang2;
+    case KEY_NAME_INDEX_HangulMode:
+      return CODE_NAME_INDEX_Lang1;
+#endif  // #ifdef XP_WIN
+
+#ifdef MOZ_WIDGET_GTK
+    case KEY_NAME_INDEX_Convert:
+      return CODE_NAME_INDEX_Convert;
+    case KEY_NAME_INDEX_NonConvert:
+      return CODE_NAME_INDEX_NonConvert;
+    case KEY_NAME_INDEX_Alphanumeric:
+      return CODE_NAME_INDEX_CapsLock;
+    case KEY_NAME_INDEX_HiraganaKatakana:
+      return CODE_NAME_INDEX_KanaMode;
+    case KEY_NAME_INDEX_ZenkakuHankaku:
+      return CODE_NAME_INDEX_Backquote;
+#endif  // #ifdef MOZ_WIDGET_GTK
+
+#ifdef ANDROID
+    case KEY_NAME_INDEX_Convert:
+      return CODE_NAME_INDEX_Convert;
+    case KEY_NAME_INDEX_NonConvert:
+      return CODE_NAME_INDEX_NonConvert;
+    case KEY_NAME_INDEX_HiraganaKatakana:
+      return CODE_NAME_INDEX_KanaMode;
+    case KEY_NAME_INDEX_ZenkakuHankaku:
+      return CODE_NAME_INDEX_Backquote;
+    case KEY_NAME_INDEX_Eisu:
+      return CODE_NAME_INDEX_Lang2;
+    case KEY_NAME_INDEX_KanjiMode:
+      return CODE_NAME_INDEX_Lang1;
+#endif  // #ifdef ANDROID
+
+#ifdef XP_MACOSX
+    case KEY_NAME_INDEX_Eisu:
+      return CODE_NAME_INDEX_Lang2;
+    case KEY_NAME_INDEX_KanjiMode:
+      return CODE_NAME_INDEX_Lang1;
+#endif  // #ifdef XP_MACOSX
+
+    default:
+      return CODE_NAME_INDEX_UNKNOWN;
+  }
+}
+
+/* static */
+Modifier WidgetKeyboardEvent::GetModifierForKeyName(
+    KeyNameIndex aKeyNameIndex) {
+  switch (aKeyNameIndex) {
+    case KEY_NAME_INDEX_Alt:
+      return MODIFIER_ALT;
+    case KEY_NAME_INDEX_AltGraph:
+      return MODIFIER_ALTGRAPH;
+    case KEY_NAME_INDEX_CapsLock:
+      return MODIFIER_CAPSLOCK;
+    case KEY_NAME_INDEX_Control:
+      return MODIFIER_CONTROL;
+    case KEY_NAME_INDEX_Fn:
+      return MODIFIER_FN;
+    case KEY_NAME_INDEX_FnLock:
+      return MODIFIER_FNLOCK;
+    // case KEY_NAME_INDEX_Hyper:
+    case KEY_NAME_INDEX_Meta:
+      return MODIFIER_META;
+    case KEY_NAME_INDEX_NumLock:
+      return MODIFIER_NUMLOCK;
+    case KEY_NAME_INDEX_ScrollLock:
+      return MODIFIER_SCROLLLOCK;
+    case KEY_NAME_INDEX_Shift:
+      return MODIFIER_SHIFT;
+    // case KEY_NAME_INDEX_Super:
+    case KEY_NAME_INDEX_Symbol:
+      return MODIFIER_SYMBOL;
+    case KEY_NAME_INDEX_SymbolLock:
+      return MODIFIER_SYMBOLLOCK;
+    default:
+      return MODIFIER_NONE;
+  }
+}
+
+/* static */
+bool WidgetKeyboardEvent::IsLockableModifier(KeyNameIndex aKeyNameIndex) {
+  switch (aKeyNameIndex) {
+    case KEY_NAME_INDEX_CapsLock:
+    case KEY_NAME_INDEX_FnLock:
+    case KEY_NAME_INDEX_NumLock:
+    case KEY_NAME_INDEX_ScrollLock:
+    case KEY_NAME_INDEX_SymbolLock:
+      return true;
+    default:
+      return false;
+  }
+}
+
+/******************************************************************************
+ * mozilla::InternalEditorInputEvent (TextEvents.h)
+ ******************************************************************************/
+
+#define NS_DEFINE_INPUTTYPE(aCPPName, aDOMName) (u"" aDOMName),
+const char16_t* const InternalEditorInputEvent::kInputTypeNames[] = {
+#include "mozilla/InputTypeList.h"
+};
+#undef NS_DEFINE_INPUTTYPE
+
+InternalEditorInputEvent::InputTypeHashtable*
+    InternalEditorInputEvent::sInputTypeHashtable = nullptr;
+
+/* static */
+void InternalEditorInputEvent::Shutdown() {
+  delete sInputTypeHashtable;
+  sInputTypeHashtable = nullptr;
+}
+
+/* static */
+void InternalEditorInputEvent::GetDOMInputTypeName(EditorInputType aInputType,
+                                                   nsAString& aInputTypeName) {
+  if (static_cast<size_t>(aInputType) >=
+      static_cast<size_t>(EditorInputType::eUnknown)) {
+    aInputTypeName.Truncate();
+    return;
+  }
+
+  MOZ_RELEASE_ASSERT(
+      static_cast<size_t>(aInputType) < ArrayLength(kInputTypeNames),
+      "Illegal input type enumeration value");
+  aInputTypeName.Assign(kInputTypeNames[static_cast<size_t>(aInputType)]);
+}
+
+/* static */
+EditorInputType InternalEditorInputEvent::GetEditorInputType(
+    const nsAString& aInputType) {
+  if (aInputType.IsEmpty()) {
+    return EditorInputType::eUnknown;
+  }
+
+  if (!sInputTypeHashtable) {
+    sInputTypeHashtable = new InputTypeHashtable(ArrayLength(kInputTypeNames));
+    for (size_t i = 0; i < ArrayLength(kInputTypeNames); i++) {
+      sInputTypeHashtable->InsertOrUpdate(nsDependentString(kInputTypeNames[i]),
+                                          static_cast<EditorInputType>(i));
+    }
+  }
+  return sInputTypeHashtable->MaybeGet(aInputType)
+      .valueOr(EditorInputType::eUnknown);
+}
+
+}  // namespace mozilla
diff --git a/widget/WidgetMessageUtils.h b/widget/WidgetMessageUtils.h
new file mode 100644
index 0000000000..5a3cd1eb7c
--- /dev/null
+++ b/widget/WidgetMessageUtils.h
@@ -0,0 +1,76 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_WidgetMessageUtils_h
+#define mozilla_WidgetMessageUtils_h
+
+#include "ipc/EnumSerializer.h"
+#include "ipc/IPCMessageUtils.h"
+#include "mozilla/DimensionRequest.h"
+#include "mozilla/GfxMessageUtils.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/widget/ThemeChangeKind.h"
+#include "nsIWidget.h"
+#include "nsStyleConsts.h"
+
+namespace IPC {
+
+template <>
+struct ParamTraits<mozilla::widget::ThemeChangeKind>
+    : public BitFlagsEnumSerializer<mozilla::widget::ThemeChangeKind,
+                                    mozilla::widget::ThemeChangeKind::AllBits> {
+};
+
+template <>
+struct ParamTraits<mozilla::LookAndFeel::IntID>
+    : ContiguousEnumSerializer<mozilla::LookAndFeel::IntID,
+                               mozilla::LookAndFeel::IntID(0),
+                               mozilla::LookAndFeel::IntID::End> {
+  using IdType = std::underlying_type_t<mozilla::LookAndFeel::IntID>;
+};
+
+template <>
+struct ParamTraits<mozilla::LookAndFeel::ColorID>
+    : ContiguousEnumSerializer<mozilla::LookAndFeel::ColorID,
+                               mozilla::LookAndFeel::ColorID(0),
+                               mozilla::LookAndFeel::ColorID::End> {
+  using IdType = std::underlying_type_t<mozilla::LookAndFeel::ColorID>;
+};
+
+template <>
+struct ParamTraits<mozilla::widget::TransparencyMode>
+    : ContiguousEnumSerializerInclusive<
+          mozilla::widget::TransparencyMode,
+          mozilla::widget::TransparencyMode::Opaque,
+          mozilla::widget::TransparencyMode::Transparent> {};
+
+template <>
+struct ParamTraits<nsCursor>
+    : ContiguousEnumSerializer<nsCursor, eCursor_standard, eCursorCount> {};
+
+template <>
+struct ParamTraits<nsIWidget::TouchpadGesturePhase>
+    : ContiguousEnumSerializerInclusive<
+          nsIWidget::TouchpadGesturePhase,
+          nsIWidget::TouchpadGesturePhase::PHASE_BEGIN,
+          nsIWidget::TouchpadGesturePhase::PHASE_END> {};
+
+template <>
+struct ParamTraits<nsIWidget::TouchPointerState>
+    : public BitFlagsEnumSerializer<nsIWidget::TouchPointerState,
+                                    nsIWidget::TouchPointerState::ALL_BITS> {};
+
+template <>
+struct ParamTraits<mozilla::DimensionKind>
+    : public ContiguousEnumSerializerInclusive<mozilla::DimensionKind,
+                                               mozilla::DimensionKind::Inner,
+                                               mozilla::DimensionKind::Outer> {
+};
+
+DEFINE_IPC_SERIALIZER_WITH_FIELDS(mozilla::DimensionRequest, mDimensionKind, mX,
+                                  mY, mWidth, mHeight);
+
+}  // namespace IPC
+
+#endif  // WidgetMessageUtils_h
diff --git a/widget/WidgetTraceEvent.h b/widget/WidgetTraceEvent.h
new file mode 100644
index 0000000000..7f85cc91c0
--- /dev/null
+++ b/widget/WidgetTraceEvent.h
@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_PUBLIC_WIDGETTRACEEVENT_H_
+#define WIDGET_PUBLIC_WIDGETTRACEEVENT_H_
+
+namespace mozilla {
+
+// Perform any required initialization in the widget backend for
+// event tracing. Return true if initialization was successful.
+bool InitWidgetTracing();
+
+// Perform any required cleanup in the widget backend for event tracing.
+void CleanUpWidgetTracing();
+
+// Fire a tracer event at the UI-thread event loop, and block until
+// the event is processed. This should only be called by
+// a thread that's not the UI thread.
+bool FireAndWaitForTracerEvent();
+
+// Signal that the event has been received by the event loop.
+void SignalTracerThread();
+
+}  // namespace mozilla
+
+#endif  // WIDGET_PUBLIC_WIDGETTRACEEVENT_H_
diff --git a/widget/WidgetUtils.cpp b/widget/WidgetUtils.cpp
new file mode 100644
index 0000000000..3bafdd0a4d
--- /dev/null
+++ b/widget/WidgetUtils.cpp
@@ -0,0 +1,134 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/WidgetUtils.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/Components.h"
+#include "mozilla/Unused.h"
+#include "nsContentUtils.h"
+#include "nsIBidiKeyboard.h"
+#include "nsIStringBundle.h"
+#include "nsTArray.h"
+#include "prenv.h"
+
+namespace mozilla {
+
+gfx::Matrix ComputeTransformForRotation(const nsIntRect& aBounds,
+                                        ScreenRotation aRotation) {
+  gfx::Matrix transform;
+  static const gfx::Float floatPi = static_cast<gfx::Float>(M_PI);
+
+  switch (aRotation) {
+    case ROTATION_0:
+      break;
+    case ROTATION_90:
+      transform.PreTranslate(aBounds.Width(), 0);
+      transform.PreRotate(floatPi / 2);
+      break;
+    case ROTATION_180:
+      transform.PreTranslate(aBounds.Width(), aBounds.Height());
+      transform.PreRotate(floatPi);
+      break;
+    case ROTATION_270:
+      transform.PreTranslate(0, aBounds.Height());
+      transform.PreRotate(floatPi * 3 / 2);
+      break;
+    default:
+      MOZ_CRASH("Unknown rotation");
+  }
+  return transform;
+}
+
+gfx::Matrix ComputeTransformForUnRotation(const nsIntRect& aBounds,
+                                          ScreenRotation aRotation) {
+  gfx::Matrix transform;
+  static const gfx::Float floatPi = static_cast<gfx::Float>(M_PI);
+
+  switch (aRotation) {
+    case ROTATION_0:
+      break;
+    case ROTATION_90:
+      transform.PreTranslate(0, aBounds.Height());
+      transform.PreRotate(floatPi * 3 / 2);
+      break;
+    case ROTATION_180:
+      transform.PreTranslate(aBounds.Width(), aBounds.Height());
+      transform.PreRotate(floatPi);
+      break;
+    case ROTATION_270:
+      transform.PreTranslate(aBounds.Width(), 0);
+      transform.PreRotate(floatPi / 2);
+      break;
+    default:
+      MOZ_CRASH("Unknown rotation");
+  }
+  return transform;
+}
+
+nsIntRect RotateRect(nsIntRect aRect, const nsIntRect& aBounds,
+                     ScreenRotation aRotation) {
+  switch (aRotation) {
+    case ROTATION_0:
+      return aRect;
+    case ROTATION_90:
+      return nsIntRect(aRect.Y(), aBounds.Width() - aRect.XMost(),
+                       aRect.Height(), aRect.Width());
+    case ROTATION_180:
+      return nsIntRect(aBounds.Width() - aRect.XMost(),
+                       aBounds.Height() - aRect.YMost(), aRect.Width(),
+                       aRect.Height());
+    case ROTATION_270:
+      return nsIntRect(aBounds.Height() - aRect.YMost(), aRect.X(),
+                       aRect.Height(), aRect.Width());
+    default:
+      MOZ_CRASH("Unknown rotation");
+  }
+}
+
+namespace widget {
+
+// static
+void WidgetUtils::SendBidiKeyboardInfoToContent() {
+  nsCOMPtr<nsIBidiKeyboard> bidiKeyboard = nsContentUtils::GetBidiKeyboard();
+  if (!bidiKeyboard) {
+    return;
+  }
+
+  bool rtl;
+  if (NS_FAILED(bidiKeyboard->IsLangRTL(&rtl))) {
+    return;
+  }
+  bool bidiKeyboards = false;
+  bidiKeyboard->GetHaveBidiKeyboards(&bidiKeyboards);
+
+  nsTArray<dom::ContentParent*> children;
+  dom::ContentParent::GetAll(children);
+  for (uint32_t i = 0; i < children.Length(); i++) {
+    Unused << children[i]->SendBidiKeyboardNotify(rtl, bidiKeyboards);
+  }
+}
+
+// static
+void WidgetUtils::GetBrandShortName(nsAString& aBrandName) {
+  aBrandName.Truncate();
+
+  nsCOMPtr<nsIStringBundleService> bundleService =
+      mozilla::components::StringBundle::Service();
+
+  nsCOMPtr<nsIStringBundle> bundle;
+  if (bundleService) {
+    bundleService->CreateBundle("chrome://branding/locale/brand.properties",
+                                getter_AddRefs(bundle));
+  }
+
+  if (bundle) {
+    bundle->GetStringFromName("brandShortName", aBrandName);
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/WidgetUtils.h b/widget/WidgetUtils.h
new file mode 100644
index 0000000000..1971c3854c
--- /dev/null
+++ b/widget/WidgetUtils.h
@@ -0,0 +1,96 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_WidgetUtils_h
+#define mozilla_WidgetUtils_h
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/gfx/Matrix.h"
+#include "nsRect.h"
+
+class nsIWidget;
+class nsPIDOMWindowOuter;
+
+namespace mozilla {
+
+// NB: these must match up with pseudo-enum in nsIScreen.idl.
+enum ScreenRotation {
+  ROTATION_0 = 0,
+  ROTATION_90,
+  ROTATION_180,
+  ROTATION_270,
+
+  ROTATION_COUNT
+};
+
+gfx::Matrix ComputeTransformForRotation(const nsIntRect& aBounds,
+                                        ScreenRotation aRotation);
+
+gfx::Matrix ComputeTransformForUnRotation(const nsIntRect& aBounds,
+                                          ScreenRotation aRotation);
+
+nsIntRect RotateRect(nsIntRect aRect, const nsIntRect& aBounds,
+                     ScreenRotation aRotation);
+
+namespace widget {
+
+class WidgetUtils {
+ public:
+  /**
+   * Shutdown() is called when "xpcom-will-shutdown" is notified.  This is
+   * useful when you need to observe the notification in XP level code under
+   * widget.
+   */
+  static void Shutdown();
+
+  /**
+   * Starting at the docshell item for the passed in DOM window this looks up
+   * the docshell tree until it finds a docshell item that has a widget.
+   */
+  static already_AddRefed<nsIWidget> DOMWindowToWidget(
+      nsPIDOMWindowOuter* aDOMWindow);
+
+  /**
+   * Compute our keyCode value (NS_VK_*) from an ASCII character.
+   */
+  static uint32_t ComputeKeyCodeFromChar(uint32_t aCharCode);
+
+  /**
+   * Get unshifted charCode and shifted charCode for aKeyCode if the keyboad
+   * layout is a Latin keyboard layout.
+   *
+   * @param aKeyCode            Our keyCode (NS_VK_*).
+   * @param aIsCapsLock         TRUE if CapsLock is Locked.  Otherwise, FALSE.
+   *                            This is used only when aKeyCode is NS_VK_[0-9].
+   * @param aUnshiftedCharCode  CharCode for aKeyCode without Shift key.
+   *                            This may be zero if aKeyCode key doesn't input
+   *                            a Latin character.
+   *                            Note that must not be nullptr.
+   * @param aShiftedCharCode    CharCode for aKeyCOde with Shift key.
+   *                            This is always 0 when aKeyCode isn't
+   *                            NS_VK_[A-Z].
+   *                            Note that must not be nullptr.
+   */
+  static void GetLatinCharCodeForKeyCode(uint32_t aKeyCode, bool aIsCapsLock,
+                                         uint32_t* aUnshiftedCharCode,
+                                         uint32_t* aShiftedCharCode);
+
+  /**
+   * Send bidi keyboard information to content process
+   */
+  static void SendBidiKeyboardInfoToContent();
+
+  /**
+   * Get branchShortName from string bundle
+   */
+  static void GetBrandShortName(nsAString& aBrandName);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_WidgetUtils_h
diff --git a/widget/WindowButtonType.h b/widget/WindowButtonType.h
new file mode 100644
index 0000000000..76314709df
--- /dev/null
+++ b/widget/WindowButtonType.h
@@ -0,0 +1,22 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_WindowButtonType_h
+#define mozilla_WindowButtonType_h
+
+#include <cstdint>
+
+namespace mozilla {
+
+enum class WindowButtonType : uint8_t {
+  Minimize,
+  Maximize,  // Also covers restore.
+  Close,
+  Count,
+};
+
+}
+
+#endif
diff --git a/widget/WindowOcclusionState.h b/widget/WindowOcclusionState.h
new file mode 100644
index 0000000000..76f70d9512
--- /dev/null
+++ b/widget/WindowOcclusionState.h
@@ -0,0 +1,34 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_WindowOcclusionState_h
+#define widget_WindowOcclusionState_h
+
+namespace mozilla {
+namespace widget {
+
+// nsWindow's window occlusion state. On Windows, it is tracked by
+// WinWindowOcclusionTracker.
+enum class OcclusionState {
+  // The window's occlusion state isn't tracked (NotifyOcclusionState()) or
+  // hasn't been computed yet.
+  UNKNOWN = 0,
+  // The window IsWindowVisibleAndFullyOpaque() [1] and:
+  // - Its bounds aren't completely covered by fully opaque windows [2]
+  VISIBLE = 1,
+  // The window IsWindowVisibleAndFullyOpaque() [1], but they all:
+  // - Have bounds completely covered by fully opaque windows [2]
+  OCCLUDED = 2,
+  // The window is not IsWindowVisibleAndFullyOpaque() [1].
+  HIDDEN = 3,
+
+  kMaxValue = HIDDEN,
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_WindowOcclusionState_h
diff --git a/widget/android/AndroidAlerts.cpp b/widget/android/AndroidAlerts.cpp
new file mode 100644
index 0000000000..456dc08290
--- /dev/null
+++ b/widget/android/AndroidAlerts.cpp
@@ -0,0 +1,159 @@
+/* -*- Mode: c++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AndroidAlerts.h"
+#include "mozilla/java/GeckoRuntimeWrappers.h"
+#include "mozilla/java/WebNotificationWrappers.h"
+#include "nsIPrincipal.h"
+#include "nsIURI.h"
+
+namespace mozilla {
+namespace widget {
+
+NS_IMPL_ISUPPORTS(AndroidAlerts, nsIAlertsService)
+
+StaticAutoPtr<AndroidAlerts::ListenerMap> AndroidAlerts::sListenerMap;
+nsTHashMap<nsStringHashKey, java::WebNotification::GlobalRef>
+    AndroidAlerts::mNotificationsMap;
+
+NS_IMETHODIMP
+AndroidAlerts::ShowAlertNotification(
+    const nsAString& aImageUrl, const nsAString& aAlertTitle,
+    const nsAString& aAlertText, bool aAlertTextClickable,
+    const nsAString& aAlertCookie, nsIObserver* aAlertListener,
+    const nsAString& aAlertName, const nsAString& aBidi, const nsAString& aLang,
+    const nsAString& aData, nsIPrincipal* aPrincipal, bool aInPrivateBrowsing,
+    bool aRequireInteraction) {
+  MOZ_ASSERT_UNREACHABLE("Should be implemented by nsAlertsService.");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+AndroidAlerts::ShowAlert(nsIAlertNotification* aAlert,
+                         nsIObserver* aAlertListener) {
+  return ShowPersistentNotification(u""_ns, aAlert, aAlertListener);
+}
+
+NS_IMETHODIMP
+AndroidAlerts::ShowPersistentNotification(const nsAString& aPersistentData,
+                                          nsIAlertNotification* aAlert,
+                                          nsIObserver* aAlertListener) {
+  // nsAlertsService disables our alerts backend if we ever return failure
+  // here. To keep the backend enabled, we always return NS_OK even if we
+  // encounter an error here.
+  nsresult rv;
+
+  nsAutoString imageUrl;
+  rv = aAlert->GetImageURL(imageUrl);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  nsAutoString title;
+  rv = aAlert->GetTitle(title);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  nsAutoString text;
+  rv = aAlert->GetText(text);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  nsAutoString cookie;
+  rv = aAlert->GetCookie(cookie);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  nsAutoString name;
+  rv = aAlert->GetName(name);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  nsAutoString lang;
+  rv = aAlert->GetLang(lang);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  nsAutoString dir;
+  rv = aAlert->GetDir(dir);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  bool requireInteraction;
+  rv = aAlert->GetRequireInteraction(&requireInteraction);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  nsCOMPtr<nsIURI> uri;
+  rv = aAlert->GetURI(getter_AddRefs(uri));
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  nsCString spec;
+  if (uri) {
+    rv = uri->GetDisplaySpec(spec);
+    NS_ENSURE_SUCCESS(rv, NS_OK);
+  }
+
+  bool silent;
+  rv = aAlert->GetSilent(&silent);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  bool privateBrowsing;
+  rv = aAlert->GetInPrivateBrowsing(&privateBrowsing);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  nsTArray<uint32_t> vibrate;
+  rv = aAlert->GetVibrate(vibrate);
+  NS_ENSURE_SUCCESS(rv, NS_OK);
+
+  if (aPersistentData.IsEmpty() && aAlertListener) {
+    if (!sListenerMap) {
+      sListenerMap = new ListenerMap();
+    }
+    // This will remove any observers already registered for this name.
+    sListenerMap->InsertOrUpdate(name, aAlertListener);
+  }
+
+  java::WebNotification::LocalRef notification = notification->New(
+      title, name, cookie, text, imageUrl, dir, lang, requireInteraction, spec,
+      silent, privateBrowsing, jni::IntArray::From(vibrate));
+  java::GeckoRuntime::LocalRef runtime = java::GeckoRuntime::GetInstance();
+  if (runtime != NULL) {
+    runtime->NotifyOnShow(notification);
+  }
+  mNotificationsMap.InsertOrUpdate(name, notification);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AndroidAlerts::CloseAlert(const nsAString& aAlertName, bool aContextClosed) {
+  java::WebNotification::LocalRef notification =
+      mNotificationsMap.Get(aAlertName);
+  if (!notification) {
+    return NS_OK;
+  }
+
+  java::GeckoRuntime::LocalRef runtime = java::GeckoRuntime::GetInstance();
+  if (runtime != NULL) {
+    runtime->NotifyOnClose(notification);
+  }
+  mNotificationsMap.Remove(aAlertName);
+
+  return NS_OK;
+}
+
+void AndroidAlerts::NotifyListener(const nsAString& aName, const char* aTopic,
+                                   const char16_t* aCookie) {
+  if (!sListenerMap) {
+    return;
+  }
+
+  nsCOMPtr<nsIObserver> listener = sListenerMap->Get(aName);
+  if (!listener) {
+    return;
+  }
+
+  listener->Observe(nullptr, aTopic, aCookie);
+
+  if ("alertfinished"_ns.Equals(aTopic)) {
+    sListenerMap->Remove(aName);
+    mNotificationsMap.Remove(aName);
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/AndroidAlerts.h b/widget/android/AndroidAlerts.h
new file mode 100644
index 0000000000..f4a9822dc1
--- /dev/null
+++ b/widget/android/AndroidAlerts.h
@@ -0,0 +1,46 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_AndroidAlerts_h__
+#define mozilla_widget_AndroidAlerts_h__
+
+#include "nsTHashMap.h"
+#include "nsInterfaceHashtable.h"
+#include "nsCOMPtr.h"
+#include "nsHashKeys.h"
+#include "nsIAlertsService.h"
+#include "nsIObserver.h"
+
+#include "mozilla/java/WebNotificationWrappers.h"
+
+#include "mozilla/StaticPtr.h"
+
+namespace mozilla {
+namespace widget {
+
+class AndroidAlerts : public nsIAlertsService {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIALERTSSERVICE
+
+  AndroidAlerts() {}
+
+  static void NotifyListener(const nsAString& aName, const char* aTopic,
+                             const char16_t* aCookie);
+
+  static nsTHashMap<nsStringHashKey, mozilla::java::WebNotification::GlobalRef>
+      mNotificationsMap;
+
+ protected:
+  virtual ~AndroidAlerts() { sListenerMap = nullptr; }
+
+  using ListenerMap = nsInterfaceHashtable<nsStringHashKey, nsIObserver>;
+  static StaticAutoPtr<ListenerMap> sListenerMap;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // nsAndroidAlerts_h__
diff --git a/widget/android/AndroidBridge.cpp b/widget/android/AndroidBridge.cpp
new file mode 100644
index 0000000000..024b64036d
--- /dev/null
+++ b/widget/android/AndroidBridge.cpp
@@ -0,0 +1,431 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <android/log.h>
+#include <dlfcn.h>
+#include <math.h>
+#include <GLES2/gl2.h>
+
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+
+#include "mozilla/Hal.h"
+#include "nsXULAppAPI.h"
+#include <prthread.h>
+#include "AndroidBridge.h"
+#include "AndroidBridgeUtilities.h"
+#include "nsAlertsUtils.h"
+#include "nsAppShell.h"
+#include "nsOSHelperAppService.h"
+#include "nsWindow.h"
+#include "mozilla/Preferences.h"
+#include "nsThreadUtils.h"
+#include "nsPresContext.h"
+#include "nsPIDOMWindow.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Mutex.h"
+#include "nsPrintfCString.h"
+#include "nsContentUtils.h"
+
+#include "EventDispatcher.h"
+
+#include "mozilla/TimeStamp.h"
+#include "mozilla/UniquePtr.h"
+#include "WidgetUtils.h"
+
+#include "mozilla/java/EventDispatcherWrappers.h"
+#include "mozilla/java/GeckoAppShellWrappers.h"
+#include "mozilla/java/GeckoThreadWrappers.h"
+
+using namespace mozilla;
+
+AndroidBridge* AndroidBridge::sBridge = nullptr;
+static jobject sGlobalContext = nullptr;
+nsTHashMap<nsStringHashKey, nsString> AndroidBridge::sStoragePaths;
+
+jmethodID AndroidBridge::GetMethodID(JNIEnv* env, jclass jClass,
+                                     const char* methodName,
+                                     const char* methodType) {
+  jmethodID methodID = env->GetMethodID(jClass, methodName, methodType);
+  if (!methodID) {
+    ALOG(
+        ">>> FATAL JNI ERROR! GetMethodID(methodName=\"%s\", "
+        "methodType=\"%s\") failed. Did ProGuard optimize away something it "
+        "shouldn't have?",
+        methodName, methodType);
+    env->ExceptionDescribe();
+    MOZ_CRASH();
+  }
+  return methodID;
+}
+
+jmethodID AndroidBridge::GetStaticMethodID(JNIEnv* env, jclass jClass,
+                                           const char* methodName,
+                                           const char* methodType) {
+  jmethodID methodID = env->GetStaticMethodID(jClass, methodName, methodType);
+  if (!methodID) {
+    ALOG(
+        ">>> FATAL JNI ERROR! GetStaticMethodID(methodName=\"%s\", "
+        "methodType=\"%s\") failed. Did ProGuard optimize away something it "
+        "shouldn't have?",
+        methodName, methodType);
+    env->ExceptionDescribe();
+    MOZ_CRASH();
+  }
+  return methodID;
+}
+
+jfieldID AndroidBridge::GetFieldID(JNIEnv* env, jclass jClass,
+                                   const char* fieldName,
+                                   const char* fieldType) {
+  jfieldID fieldID = env->GetFieldID(jClass, fieldName, fieldType);
+  if (!fieldID) {
+    ALOG(
+        ">>> FATAL JNI ERROR! GetFieldID(fieldName=\"%s\", "
+        "fieldType=\"%s\") failed. Did ProGuard optimize away something it "
+        "shouldn't have?",
+        fieldName, fieldType);
+    env->ExceptionDescribe();
+    MOZ_CRASH();
+  }
+  return fieldID;
+}
+
+jfieldID AndroidBridge::GetStaticFieldID(JNIEnv* env, jclass jClass,
+                                         const char* fieldName,
+                                         const char* fieldType) {
+  jfieldID fieldID = env->GetStaticFieldID(jClass, fieldName, fieldType);
+  if (!fieldID) {
+    ALOG(
+        ">>> FATAL JNI ERROR! GetStaticFieldID(fieldName=\"%s\", "
+        "fieldType=\"%s\") failed. Did ProGuard optimize away something it "
+        "shouldn't have?",
+        fieldName, fieldType);
+    env->ExceptionDescribe();
+    MOZ_CRASH();
+  }
+  return fieldID;
+}
+
+void AndroidBridge::ConstructBridge() {
+  /* NSS hack -- bionic doesn't handle recursive unloads correctly,
+   * because library finalizer functions are called with the dynamic
+   * linker lock still held.  This results in a deadlock when trying
+   * to call dlclose() while we're already inside dlclose().
+   * Conveniently, NSS has an env var that can prevent it from unloading.
+   */
+  putenv(const_cast<char*>("NSS_DISABLE_UNLOAD=1"));
+
+  MOZ_ASSERT(!sBridge);
+  sBridge = new AndroidBridge();
+}
+
+void AndroidBridge::DeconstructBridge() {
+  if (sBridge) {
+    delete sBridge;
+    // AndroidBridge destruction requires sBridge to still be valid,
+    // so we set sBridge to nullptr after deleting it.
+    sBridge = nullptr;
+  }
+}
+
+AndroidBridge::~AndroidBridge() {}
+
+AndroidBridge::AndroidBridge() {
+  ALOG_BRIDGE("AndroidBridge::Init");
+
+  JNIEnv* const jEnv = jni::GetGeckoThreadEnv();
+  AutoLocalJNIFrame jniFrame(jEnv);
+
+  mMessageQueue = java::GeckoThread::MsgQueue();
+  auto msgQueueClass = jni::Class::LocalRef::Adopt(
+      jEnv, jEnv->GetObjectClass(mMessageQueue.Get()));
+  // mMessageQueueNext must not be null
+  mMessageQueueNext =
+      GetMethodID(jEnv, msgQueueClass.Get(), "next", "()Landroid/os/Message;");
+  // mMessageQueueMessages may be null (e.g. due to proguard optimization)
+  mMessageQueueMessages = jEnv->GetFieldID(msgQueueClass.Get(), "mMessages",
+                                           "Landroid/os/Message;");
+}
+
+void AndroidBridge::Vibrate(const nsTArray<uint32_t>& aPattern) {
+  ALOG_BRIDGE("%s", __PRETTY_FUNCTION__);
+
+  uint32_t len = aPattern.Length();
+  if (!len) {
+    ALOG_BRIDGE("  invalid 0-length array");
+    return;
+  }
+
+  // It's clear if this worth special-casing, but it creates less
+  // java junk, so dodges the GC.
+  if (len == 1) {
+    jlong d = aPattern[0];
+    if (d < 0) {
+      ALOG_BRIDGE("  invalid vibration duration < 0");
+      return;
+    }
+    java::GeckoAppShell::Vibrate(d);
+    return;
+  }
+
+  // First element of the array vibrate() expects is how long to wait
+  // *before* vibrating.  For us, this is always 0.
+
+  JNIEnv* const env = jni::GetGeckoThreadEnv();
+  AutoLocalJNIFrame jniFrame(env, 1);
+
+  jlongArray array = env->NewLongArray(len + 1);
+  if (!array) {
+    ALOG_BRIDGE("  failed to allocate array");
+    return;
+  }
+
+  jlong* elts = env->GetLongArrayElements(array, nullptr);
+  elts[0] = 0;
+  for (uint32_t i = 0; i < aPattern.Length(); ++i) {
+    jlong d = aPattern[i];
+    if (d < 0) {
+      ALOG_BRIDGE("  invalid vibration duration < 0");
+      env->ReleaseLongArrayElements(array, elts, JNI_ABORT);
+      return;
+    }
+    elts[i + 1] = d;
+  }
+  env->ReleaseLongArrayElements(array, elts, 0);
+
+  java::GeckoAppShell::Vibrate(jni::LongArray::Ref::From(array),
+                               -1 /* don't repeat */);
+}
+
+void AndroidBridge::GetIconForExtension(const nsACString& aFileExt,
+                                        uint32_t aIconSize,
+                                        uint8_t* const aBuf) {
+  ALOG_BRIDGE("AndroidBridge::GetIconForExtension");
+  NS_ASSERTION(aBuf != nullptr,
+               "AndroidBridge::GetIconForExtension: aBuf is null!");
+  if (!aBuf) return;
+
+  auto arr = java::GeckoAppShell::GetIconForExtension(
+      NS_ConvertUTF8toUTF16(aFileExt), aIconSize);
+
+  NS_ASSERTION(
+      arr != nullptr,
+      "AndroidBridge::GetIconForExtension: Returned pixels array is null!");
+  if (!arr) return;
+
+  JNIEnv* const env = arr.Env();
+  uint32_t len = static_cast<uint32_t>(env->GetArrayLength(arr.Get()));
+  jbyte* elements = env->GetByteArrayElements(arr.Get(), 0);
+
+  uint32_t bufSize = aIconSize * aIconSize * 4;
+  NS_ASSERTION(
+      len == bufSize,
+      "AndroidBridge::GetIconForExtension: Pixels array is incomplete!");
+  if (len == bufSize) memcpy(aBuf, elements, bufSize);
+
+  env->ReleaseByteArrayElements(arr.Get(), elements, 0);
+}
+
+namespace mozilla {
+class TracerRunnable : public Runnable {
+ public:
+  TracerRunnable() : Runnable("TracerRunnable") {
+    mTracerLock = new Mutex("TracerRunnable");
+    mTracerCondVar = new CondVar(*mTracerLock, "TracerRunnable");
+    mMainThread = do_GetMainThread();
+  }
+  ~TracerRunnable() {
+    delete mTracerCondVar;
+    delete mTracerLock;
+    mTracerLock = nullptr;
+    mTracerCondVar = nullptr;
+  }
+
+  virtual nsresult Run() {
+    MutexAutoLock lock(*mTracerLock);
+    if (!AndroidBridge::Bridge()) return NS_OK;
+
+    mHasRun = true;
+    mTracerCondVar->Notify();
+    return NS_OK;
+  }
+
+  bool Fire() {
+    if (!mTracerLock || !mTracerCondVar) return false;
+    MutexAutoLock lock(*mTracerLock);
+    mHasRun = false;
+    mMainThread->Dispatch(this, NS_DISPATCH_NORMAL);
+    while (!mHasRun) mTracerCondVar->Wait();
+    return true;
+  }
+
+  void Signal() {
+    MutexAutoLock lock(*mTracerLock);
+    mHasRun = true;
+    mTracerCondVar->Notify();
+  }
+
+ private:
+  Mutex* mTracerLock;
+  CondVar* mTracerCondVar;
+  bool mHasRun;
+  nsCOMPtr<nsIThread> mMainThread;
+};
+StaticRefPtr<TracerRunnable> sTracerRunnable;
+
+bool InitWidgetTracing() {
+  if (!sTracerRunnable) sTracerRunnable = new TracerRunnable();
+  return true;
+}
+
+void CleanUpWidgetTracing() { sTracerRunnable = nullptr; }
+
+bool FireAndWaitForTracerEvent() {
+  if (sTracerRunnable) return sTracerRunnable->Fire();
+  return false;
+}
+
+void SignalTracerThread() {
+  if (sTracerRunnable) return sTracerRunnable->Signal();
+}
+
+}  // namespace mozilla
+
+void AndroidBridge::GetCurrentBatteryInformation(
+    hal::BatteryInformation* aBatteryInfo) {
+  ALOG_BRIDGE("AndroidBridge::GetCurrentBatteryInformation");
+
+  // To prevent calling too many methods through JNI, the Java method returns
+  // an array of double even if we actually want a double and a boolean.
+  auto arr = java::GeckoAppShell::GetCurrentBatteryInformation();
+
+  JNIEnv* const env = arr.Env();
+  if (!arr || env->GetArrayLength(arr.Get()) != 3) {
+    return;
+  }
+
+  jdouble* info = env->GetDoubleArrayElements(arr.Get(), 0);
+
+  aBatteryInfo->level() = info[0];
+  aBatteryInfo->charging() = info[1] == 1.0f;
+  aBatteryInfo->remainingTime() = info[2];
+
+  env->ReleaseDoubleArrayElements(arr.Get(), info, 0);
+}
+
+void AndroidBridge::GetCurrentNetworkInformation(
+    hal::NetworkInformation* aNetworkInfo) {
+  ALOG_BRIDGE("AndroidBridge::GetCurrentNetworkInformation");
+
+  // To prevent calling too many methods through JNI, the Java method returns
+  // an array of double even if we actually want an integer, a boolean, and an
+  // integer.
+
+  auto arr = java::GeckoAppShell::GetCurrentNetworkInformation();
+
+  JNIEnv* const env = arr.Env();
+  if (!arr || env->GetArrayLength(arr.Get()) != 3) {
+    return;
+  }
+
+  jdouble* info = env->GetDoubleArrayElements(arr.Get(), 0);
+
+  aNetworkInfo->type() = info[0];
+  aNetworkInfo->isWifi() = info[1] == 1.0f;
+  aNetworkInfo->dhcpGateway() = info[2];
+
+  env->ReleaseDoubleArrayElements(arr.Get(), info, 0);
+}
+
+jobject AndroidBridge::GetGlobalContextRef() {
+  // The context object can change, so get a fresh copy every time.
+  auto context = java::GeckoAppShell::GetApplicationContext();
+  sGlobalContext = jni::Object::GlobalRef(context).Forget();
+  MOZ_ASSERT(sGlobalContext);
+  return sGlobalContext;
+}
+
+/* Implementation file */
+NS_IMPL_ISUPPORTS(nsAndroidBridge, nsIAndroidEventDispatcher, nsIAndroidBridge)
+
+nsAndroidBridge::nsAndroidBridge() {
+  if (jni::IsAvailable()) {
+    RefPtr<widget::EventDispatcher> dispatcher = new widget::EventDispatcher();
+    dispatcher->Attach(java::EventDispatcher::GetInstance(),
+                       /* window */ nullptr);
+    mEventDispatcher = dispatcher;
+  }
+}
+
+NS_IMETHODIMP
+nsAndroidBridge::GetDispatcherByName(const char* aName,
+                                     nsIAndroidEventDispatcher** aResult) {
+  if (!jni::IsAvailable()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<widget::EventDispatcher> dispatcher = new widget::EventDispatcher();
+  dispatcher->Attach(java::EventDispatcher::ByName(aName),
+                     /* window */ nullptr);
+  dispatcher.forget(aResult);
+  return NS_OK;
+}
+
+nsAndroidBridge::~nsAndroidBridge() {}
+
+hal::ScreenOrientation AndroidBridge::GetScreenOrientation() {
+  ALOG_BRIDGE("AndroidBridge::GetScreenOrientation");
+
+  int16_t orientation = java::GeckoAppShell::GetScreenOrientation();
+
+  return hal::ScreenOrientation(orientation);
+}
+
+uint16_t AndroidBridge::GetScreenAngle() {
+  return java::GeckoAppShell::GetScreenAngle();
+}
+
+nsresult AndroidBridge::GetProxyForURI(const nsACString& aSpec,
+                                       const nsACString& aScheme,
+                                       const nsACString& aHost,
+                                       const int32_t aPort,
+                                       nsACString& aResult) {
+  if (!jni::IsAvailable()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  auto jstrRet =
+      java::GeckoAppShell::GetProxyForURI(aSpec, aScheme, aHost, aPort);
+
+  if (!jstrRet) return NS_ERROR_FAILURE;
+
+  aResult = jstrRet->ToCString();
+  return NS_OK;
+}
+
+bool AndroidBridge::PumpMessageLoop() {
+  JNIEnv* const env = jni::GetGeckoThreadEnv();
+
+  if (mMessageQueueMessages) {
+    auto msg = jni::Object::LocalRef::Adopt(
+        env, env->GetObjectField(mMessageQueue.Get(), mMessageQueueMessages));
+    // if queue.mMessages is null, queue.next() will block, which we don't
+    // want. It turns out to be an order of magnitude more performant to do
+    // this extra check here and block less vs. one fewer checks here and
+    // more blocking.
+    if (!msg) {
+      return false;
+    }
+  }
+
+  auto msg = jni::Object::LocalRef::Adopt(
+      env, env->CallObjectMethod(mMessageQueue.Get(), mMessageQueueNext));
+  if (!msg) {
+    return false;
+  }
+
+  return java::GeckoThread::PumpMessageLoop(msg);
+}
diff --git a/widget/android/AndroidBridge.h b/widget/android/AndroidBridge.h
new file mode 100644
index 0000000000..f2070ef31a
--- /dev/null
+++ b/widget/android/AndroidBridge.h
@@ -0,0 +1,275 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef AndroidBridge_h__
+#define AndroidBridge_h__
+
+#include <unistd.h>  // for gettid
+
+#include "nsCOMPtr.h"
+
+#include "mozilla/jni/Refs.h"
+
+#include "nsIMutableArray.h"
+#include "nsIMIMEInfo.h"
+
+#include "nsIAndroidBridge.h"
+
+#include "mozilla/jni/Utils.h"
+#include "nsTHashMap.h"
+
+// Some debug #defines
+// #define DEBUG_ANDROID_EVENTS
+// #define DEBUG_ANDROID_WIDGET
+
+namespace mozilla {
+
+class AutoLocalJNIFrame;
+
+namespace hal {
+class BatteryInformation;
+class NetworkInformation;
+enum class ScreenOrientation : uint32_t;
+}  // namespace hal
+
+class AndroidBridge final {
+ public:
+  static bool IsJavaUiThread() {
+    return mozilla::jni::GetUIThreadId() == gettid();
+  }
+
+  static void ConstructBridge();
+  static void DeconstructBridge();
+
+  static AndroidBridge* Bridge() { return sBridge; }
+
+  bool GetHandlersForURL(const nsAString& aURL,
+                         nsIMutableArray* handlersArray = nullptr,
+                         nsIHandlerApp** aDefaultApp = nullptr,
+                         const nsAString& aAction = u""_ns);
+
+  bool GetHandlersForMimeType(const nsAString& aMimeType,
+                              nsIMutableArray* handlersArray = nullptr,
+                              nsIHandlerApp** aDefaultApp = nullptr,
+                              const nsAString& aAction = u""_ns);
+
+  void GetMimeTypeFromExtensions(const nsACString& aFileExt,
+                                 nsCString& aMimeType);
+  void GetExtensionFromMimeType(const nsACString& aMimeType,
+                                nsACString& aFileExt);
+
+  void Vibrate(const nsTArray<uint32_t>& aPattern);
+
+  void GetIconForExtension(const nsACString& aFileExt, uint32_t aIconSize,
+                           uint8_t* const aBuf);
+
+  // Returns a global reference to the Context for Fennec's Activity. The
+  // caller is responsible for ensuring this doesn't leak by calling
+  // DeleteGlobalRef() when the context is no longer needed.
+  jobject GetGlobalContextRef(void);
+
+  void GetCurrentBatteryInformation(hal::BatteryInformation* aBatteryInfo);
+
+  void GetCurrentNetworkInformation(hal::NetworkInformation* aNetworkInfo);
+
+  hal::ScreenOrientation GetScreenOrientation();
+  uint16_t GetScreenAngle();
+
+  nsresult GetProxyForURI(const nsACString& aSpec, const nsACString& aScheme,
+                          const nsACString& aHost, const int32_t aPort,
+                          nsACString& aResult);
+
+  bool PumpMessageLoop();
+
+  // Utility methods.
+  static jfieldID GetFieldID(JNIEnv* env, jclass jClass, const char* fieldName,
+                             const char* fieldType);
+  static jfieldID GetStaticFieldID(JNIEnv* env, jclass jClass,
+                                   const char* fieldName,
+                                   const char* fieldType);
+  static jmethodID GetMethodID(JNIEnv* env, jclass jClass,
+                               const char* methodName, const char* methodType);
+  static jmethodID GetStaticMethodID(JNIEnv* env, jclass jClass,
+                                     const char* methodName,
+                                     const char* methodType);
+
+  static jni::Object::LocalRef ChannelCreate(jni::Object::Param);
+
+  static void InputStreamClose(jni::Object::Param obj);
+  static uint32_t InputStreamAvailable(jni::Object::Param obj);
+  static nsresult InputStreamRead(jni::Object::Param obj, char* aBuf,
+                                  uint32_t aCount, uint32_t* aRead);
+
+ protected:
+  static nsTHashMap<nsStringHashKey, nsString> sStoragePaths;
+
+  static AndroidBridge* sBridge;
+
+  AndroidBridge();
+  ~AndroidBridge();
+
+  jni::Object::GlobalRef mMessageQueue;
+  jfieldID mMessageQueueMessages;
+  jmethodID mMessageQueueNext;
+};
+
+class AutoJNIClass {
+ private:
+  JNIEnv* const mEnv;
+  const jclass mClass;
+
+ public:
+  AutoJNIClass(JNIEnv* jEnv, const char* name)
+      : mEnv(jEnv), mClass(jni::GetClassRef(jEnv, name)) {}
+
+  ~AutoJNIClass() { mEnv->DeleteLocalRef(mClass); }
+
+  jclass getRawRef() const { return mClass; }
+
+  jclass getGlobalRef() const {
+    return static_cast<jclass>(mEnv->NewGlobalRef(mClass));
+  }
+
+  jfieldID getField(const char* name, const char* type) const {
+    return AndroidBridge::GetFieldID(mEnv, mClass, name, type);
+  }
+
+  jfieldID getStaticField(const char* name, const char* type) const {
+    return AndroidBridge::GetStaticFieldID(mEnv, mClass, name, type);
+  }
+
+  jmethodID getMethod(const char* name, const char* type) const {
+    return AndroidBridge::GetMethodID(mEnv, mClass, name, type);
+  }
+
+  jmethodID getStaticMethod(const char* name, const char* type) const {
+    return AndroidBridge::GetStaticMethodID(mEnv, mClass, name, type);
+  }
+};
+
+class AutoJObject {
+ public:
+  explicit AutoJObject(JNIEnv* aJNIEnv = nullptr) : mObject(nullptr) {
+    mJNIEnv = aJNIEnv ? aJNIEnv : jni::GetGeckoThreadEnv();
+  }
+
+  AutoJObject(JNIEnv* aJNIEnv, jobject aObject) {
+    mJNIEnv = aJNIEnv ? aJNIEnv : jni::GetGeckoThreadEnv();
+    mObject = aObject;
+  }
+
+  ~AutoJObject() {
+    if (mObject) mJNIEnv->DeleteLocalRef(mObject);
+  }
+
+  jobject operator=(jobject aObject) {
+    if (mObject) {
+      mJNIEnv->DeleteLocalRef(mObject);
+    }
+    return mObject = aObject;
+  }
+
+  operator jobject() { return mObject; }
+
+ private:
+  JNIEnv* mJNIEnv;
+  jobject mObject;
+};
+
+class AutoLocalJNIFrame {
+ public:
+  explicit AutoLocalJNIFrame(int nEntries = 15)
+      : mEntries(nEntries),
+        mJNIEnv(jni::GetGeckoThreadEnv()),
+        mHasFrameBeenPushed(false) {
+    MOZ_ASSERT(mJNIEnv);
+    Push();
+  }
+
+  explicit AutoLocalJNIFrame(JNIEnv* aJNIEnv, int nEntries = 15)
+      : mEntries(nEntries),
+        mJNIEnv(aJNIEnv ? aJNIEnv : jni::GetGeckoThreadEnv()),
+        mHasFrameBeenPushed(false) {
+    MOZ_ASSERT(mJNIEnv);
+    Push();
+  }
+
+  ~AutoLocalJNIFrame() {
+    if (mHasFrameBeenPushed) {
+      Pop();
+    }
+  }
+
+  JNIEnv* GetEnv() { return mJNIEnv; }
+
+  bool CheckForException() {
+    if (mJNIEnv->ExceptionCheck()) {
+      MOZ_CATCH_JNI_EXCEPTION(mJNIEnv);
+      return true;
+    }
+    return false;
+  }
+
+  // Note! Calling Purge makes all previous local refs created in
+  // the AutoLocalJNIFrame's scope INVALID; be sure that you locked down
+  // any local refs that you need to keep around in global refs!
+  void Purge() {
+    Pop();
+    Push();
+  }
+
+  template <typename ReturnType = jobject>
+  ReturnType Pop(ReturnType aResult = nullptr) {
+    MOZ_ASSERT(mHasFrameBeenPushed);
+    mHasFrameBeenPushed = false;
+    return static_cast<ReturnType>(
+        mJNIEnv->PopLocalFrame(static_cast<jobject>(aResult)));
+  }
+
+ private:
+  void Push() {
+    MOZ_ASSERT(!mHasFrameBeenPushed);
+    // Make sure there is enough space to store a local ref to the
+    // exception.  I am not completely sure this is needed, but does
+    // not hurt.
+    if (mJNIEnv->PushLocalFrame(mEntries + 1) != 0) {
+      CheckForException();
+      return;
+    }
+    mHasFrameBeenPushed = true;
+  }
+
+  const int mEntries;
+  JNIEnv* const mJNIEnv;
+  bool mHasFrameBeenPushed;
+};
+
+}  // namespace mozilla
+
+#define NS_ANDROIDBRIDGE_CID                         \
+  {                                                  \
+    0x0FE2321D, 0xEBD9, 0x467D, {                    \
+      0xA7, 0x43, 0x03, 0xA6, 0x8D, 0x40, 0x59, 0x9E \
+    }                                                \
+  }
+
+class nsAndroidBridge final : public nsIAndroidBridge {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIANDROIDBRIDGE
+
+  NS_FORWARD_SAFE_NSIANDROIDEVENTDISPATCHER(mEventDispatcher)
+
+  nsAndroidBridge();
+
+ private:
+  ~nsAndroidBridge();
+
+  nsCOMPtr<nsIAndroidEventDispatcher> mEventDispatcher;
+
+ protected:
+};
+
+#endif /* AndroidBridge_h__ */
diff --git a/widget/android/AndroidBridgeUtilities.h b/widget/android/AndroidBridgeUtilities.h
new file mode 100644
index 0000000000..2d67c7ff46
--- /dev/null
+++ b/widget/android/AndroidBridgeUtilities.h
@@ -0,0 +1,19 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ALOG
+#  if defined(DEBUG) || defined(FORCE_ALOG)
+#    define ALOG(args...) __android_log_print(ANDROID_LOG_INFO, "Gecko", ##args)
+#  else
+#    define ALOG(args...) ((void)0)
+#  endif
+#endif
+
+#ifdef DEBUG
+#  define ALOG_BRIDGE(args...) ALOG(args)
+#else
+#  define ALOG_BRIDGE(args...) ((void)0)
+#endif
diff --git a/widget/android/AndroidCompositorWidget.cpp b/widget/android/AndroidCompositorWidget.cpp
new file mode 100644
index 0000000000..a7eeb665e1
--- /dev/null
+++ b/widget/android/AndroidCompositorWidget.cpp
@@ -0,0 +1,105 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=2 et tw=80 : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AndroidCompositorWidget.h"
+
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "nsWindow.h"
+
+namespace mozilla {
+namespace widget {
+
+AndroidCompositorWidget::AndroidCompositorWidget(
+    const AndroidCompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions)
+    : CompositorWidget(aOptions),
+      mWidgetId(aInitData.widgetId()),
+      mNativeWindow(nullptr),
+      mFormat(WINDOW_FORMAT_RGBA_8888),
+      mClientSize(aInitData.clientSize()) {}
+
+AndroidCompositorWidget::~AndroidCompositorWidget() {
+  if (mNativeWindow) {
+    ANativeWindow_release(mNativeWindow);
+  }
+}
+
+already_AddRefed<gfx::DrawTarget>
+AndroidCompositorWidget::StartRemoteDrawingInRegion(
+    const LayoutDeviceIntRegion& aInvalidRegion,
+    layers::BufferMode* aBufferMode) {
+  if (!mNativeWindow) {
+    EGLNativeWindowType window = GetEGLNativeWindow();
+    JNIEnv* const env = jni::GetEnvForThread();
+    mNativeWindow =
+        ANativeWindow_fromSurface(env, reinterpret_cast<jobject>(window));
+    if (mNativeWindow) {
+      mFormat = ANativeWindow_getFormat(mNativeWindow);
+      ANativeWindow_acquire(mNativeWindow);
+    } else {
+      return nullptr;
+    }
+  }
+
+  if (mFormat != WINDOW_FORMAT_RGBA_8888 &&
+      mFormat != WINDOW_FORMAT_RGBX_8888) {
+    gfxCriticalNoteOnce << "Non supported format: " << mFormat;
+    return nullptr;
+  }
+
+  // XXX Handle inOutDirtyBounds
+  if (ANativeWindow_lock(mNativeWindow, &mBuffer, nullptr) != 0) {
+    return nullptr;
+  }
+
+  const int bpp = 4;
+  gfx::SurfaceFormat format = gfx::SurfaceFormat::R8G8B8A8;
+  if (mFormat == WINDOW_FORMAT_RGBX_8888) {
+    format = gfx::SurfaceFormat::R8G8B8X8;
+  }
+
+  RefPtr<gfx::DrawTarget> dt = gfx::Factory::CreateDrawTargetForData(
+      gfx::BackendType::SKIA, static_cast<unsigned char*>(mBuffer.bits),
+      gfx::IntSize(mBuffer.width, mBuffer.height), mBuffer.stride * bpp, format,
+      true);
+
+  return dt.forget();
+}
+
+void AndroidCompositorWidget::EndRemoteDrawingInRegion(
+    gfx::DrawTarget* aDrawTarget, const LayoutDeviceIntRegion& aInvalidRegion) {
+  ANativeWindow_unlockAndPost(mNativeWindow);
+}
+
+bool AndroidCompositorWidget::OnResumeComposition() {
+  OnCompositorSurfaceChanged();
+
+  if (!mSurface) {
+    gfxCriticalError() << "OnResumeComposition called with null Surface";
+    return false;
+  }
+
+  return true;
+}
+
+EGLNativeWindowType AndroidCompositorWidget::GetEGLNativeWindow() {
+  return (EGLNativeWindowType)mSurface.Get();
+}
+
+LayoutDeviceIntSize AndroidCompositorWidget::GetClientSize() {
+  return mClientSize;
+}
+
+void AndroidCompositorWidget::NotifyClientSizeChanged(
+    const LayoutDeviceIntSize& aClientSize) {
+  mClientSize =
+      LayoutDeviceIntSize(std::min(aClientSize.width, MOZ_WIDGET_MAX_SIZE),
+                          std::min(aClientSize.height, MOZ_WIDGET_MAX_SIZE));
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/AndroidCompositorWidget.h b/widget/android/AndroidCompositorWidget.h
new file mode 100644
index 0000000000..c478477b5f
--- /dev/null
+++ b/widget/android/AndroidCompositorWidget.h
@@ -0,0 +1,70 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_AndroidCompositorWidget_h
+#define mozilla_widget_AndroidCompositorWidget_h
+
+#include "CompositorWidget.h"
+#include "AndroidNativeWindow.h"
+#include "GLDefs.h"
+
+namespace mozilla {
+namespace widget {
+
+class PlatformCompositorWidgetDelegate : public CompositorWidgetDelegate {
+ public:
+  virtual void NotifyClientSizeChanged(
+      const LayoutDeviceIntSize& aClientSize) = 0;
+
+  // CompositorWidgetDelegate Overrides
+  PlatformCompositorWidgetDelegate* AsPlatformSpecificDelegate() override {
+    return this;
+  }
+};
+
+class AndroidCompositorWidgetInitData;
+
+class AndroidCompositorWidget : public CompositorWidget {
+ public:
+  AndroidCompositorWidget(const AndroidCompositorWidgetInitData& aInitData,
+                          const layers::CompositorOptions& aOptions);
+  ~AndroidCompositorWidget() override;
+
+  EGLNativeWindowType GetEGLNativeWindow();
+
+  // CompositorWidget overrides
+
+  already_AddRefed<gfx::DrawTarget> StartRemoteDrawingInRegion(
+      const LayoutDeviceIntRegion& aInvalidRegion,
+      layers::BufferMode* aBufferMode) override;
+  void EndRemoteDrawingInRegion(
+      gfx::DrawTarget* aDrawTarget,
+      const LayoutDeviceIntRegion& aInvalidRegion) override;
+
+  bool OnResumeComposition() override;
+
+  AndroidCompositorWidget* AsAndroid() override { return this; }
+
+  LayoutDeviceIntSize GetClientSize() override;
+  void NotifyClientSizeChanged(const LayoutDeviceIntSize& aClientSize);
+
+ protected:
+  int32_t mWidgetId;
+  java::sdk::Surface::GlobalRef mSurface;
+  ANativeWindow* mNativeWindow;
+  ANativeWindow_Buffer mBuffer;
+  int32_t mFormat;
+  LayoutDeviceIntSize mClientSize;
+
+ private:
+  // Called whenever the compositor surface may have changed. The derived class
+  // should update mSurface to the new compositor surface.
+  virtual void OnCompositorSurfaceChanged() = 0;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_AndroidCompositorWidget_h
diff --git a/widget/android/AndroidContentController.cpp b/widget/android/AndroidContentController.cpp
new file mode 100644
index 0000000000..c1029fd4a2
--- /dev/null
+++ b/widget/android/AndroidContentController.cpp
@@ -0,0 +1,70 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AndroidContentController.h"
+
+#include "AndroidBridge.h"
+#include "base/message_loop.h"
+#include "mozilla/layers/APZCCallbackHelper.h"
+#include "mozilla/layers/IAPZCTreeManager.h"
+#include "nsIObserverService.h"
+#include "nsLayoutUtils.h"
+#include "nsWindow.h"
+
+using mozilla::layers::IAPZCTreeManager;
+
+namespace mozilla {
+namespace widget {
+
+void AndroidContentController::Destroy() {
+  mAndroidWindow = nullptr;
+  ChromeProcessController::Destroy();
+}
+
+void AndroidContentController::UpdateOverscrollVelocity(
+    const ScrollableLayerGuid& aGuid, const float aX, const float aY,
+    const bool aIsRootContent) {
+  if (aIsRootContent && mAndroidWindow) {
+    mAndroidWindow->UpdateOverscrollVelocity(aX, aY);
+  }
+}
+
+void AndroidContentController::UpdateOverscrollOffset(
+    const ScrollableLayerGuid& aGuid, const float aX, const float aY,
+    const bool aIsRootContent) {
+  if (aIsRootContent && mAndroidWindow) {
+    mAndroidWindow->UpdateOverscrollOffset(aX, aY);
+  }
+}
+
+void AndroidContentController::NotifyAPZStateChange(
+    const ScrollableLayerGuid& aGuid, APZStateChange aChange, int aArg,
+    Maybe<uint64_t> aInputBlockId) {
+  // This function may get invoked twice, if the first invocation is not on
+  // the main thread then the ChromeProcessController version of this function
+  // will redispatch to the main thread. We want to make sure that our handling
+  // only happens on the main thread.
+  ChromeProcessController::NotifyAPZStateChange(aGuid, aChange, aArg,
+                                                aInputBlockId);
+  if (NS_IsMainThread()) {
+    nsCOMPtr<nsIObserverService> observerService =
+        mozilla::services::GetObserverService();
+    if (aChange ==
+        layers::GeckoContentController::APZStateChange::eTransformEnd) {
+      // This is used by tests to determine when the APZ is done doing whatever
+      // it's doing. XXX generify this as needed when writing additional tests.
+      observerService->NotifyObservers(nullptr, "APZ:TransformEnd", nullptr);
+      observerService->NotifyObservers(nullptr, "PanZoom:StateChange",
+                                       u"NOTHING");
+    } else if (aChange == layers::GeckoContentController::APZStateChange::
+                              eTransformBegin) {
+      observerService->NotifyObservers(nullptr, "PanZoom:StateChange",
+                                       u"PANNING");
+    }
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/AndroidContentController.h b/widget/android/AndroidContentController.h
new file mode 100644
index 0000000000..04640deb4e
--- /dev/null
+++ b/widget/android/AndroidContentController.h
@@ -0,0 +1,52 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef AndroidContentController_h__
+#define AndroidContentController_h__
+
+#include "mozilla/layers/ChromeProcessController.h"
+#include "mozilla/EventForwards.h"  // for Modifiers
+#include "mozilla/StaticPtr.h"
+#include "mozilla/TimeStamp.h"
+#include "nsTArray.h"
+#include "nsWindow.h"
+
+namespace mozilla {
+namespace layers {
+class APZEventState;
+class IAPZCTreeManager;
+}  // namespace layers
+namespace widget {
+
+class AndroidContentController final
+    : public mozilla::layers::ChromeProcessController {
+ public:
+  AndroidContentController(nsWindow* aWindow,
+                           mozilla::layers::APZEventState* aAPZEventState,
+                           mozilla::layers::IAPZCTreeManager* aAPZCTreeManager)
+      : mozilla::layers::ChromeProcessController(aWindow, aAPZEventState,
+                                                 aAPZCTreeManager),
+        mAndroidWindow(aWindow) {}
+
+  // ChromeProcessController methods
+  virtual void Destroy() override;
+  void UpdateOverscrollVelocity(const ScrollableLayerGuid& aGuid,
+                                const float aX, const float aY,
+                                const bool aIsRootContent) override;
+  void UpdateOverscrollOffset(const ScrollableLayerGuid& aGuid, const float aX,
+                              const float aY,
+                              const bool aIsRootContent) override;
+  void NotifyAPZStateChange(const ScrollableLayerGuid& aGuid,
+                            APZStateChange aChange, int aArg,
+                            Maybe<uint64_t> aInputBlockId) override;
+
+ private:
+  nsWindow* mAndroidWindow;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/android/AndroidUiThread.cpp b/widget/android/AndroidUiThread.cpp
new file mode 100644
index 0000000000..97a5105787
--- /dev/null
+++ b/widget/android/AndroidUiThread.cpp
@@ -0,0 +1,373 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "base/message_loop.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/EventQueue.h"
+#include "mozilla/java/GeckoThreadWrappers.h"
+#include "mozilla/LinkedList.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/ThreadEventQueue.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/UniquePtr.h"
+#include "GeckoProfiler.h"
+#include "nsThread.h"
+#include "nsThreadManager.h"
+#include "nsThreadUtils.h"
+
+#include <android/api-level.h>
+#include <pthread.h>
+
+using namespace mozilla;
+
+namespace {
+
+class AndroidUiThread;
+class AndroidUiTask;
+
+StaticAutoPtr<LinkedList<AndroidUiTask> > sTaskQueue;
+StaticAutoPtr<mozilla::Mutex> sTaskQueueLock;
+StaticRefPtr<AndroidUiThread> sThread;
+static bool sThreadDestroyed;
+static MessageLoop* sMessageLoop;
+static Atomic<Monitor*> sMessageLoopAccessMonitor;
+
+void EnqueueTask(already_AddRefed<nsIRunnable> aTask, int aDelayMs);
+
+/*
+ * The AndroidUiThread is derived from nsThread so that nsIRunnable objects that
+ * get dispatched may be intercepted. Only nsIRunnable objects that need to be
+ * synchronously executed are passed into the nsThread to be queued. All other
+ * nsIRunnable object are immediately dispatched to the Android UI thread.
+ * AndroidUiThread is derived from nsThread instead of being an nsIEventTarget
+ * wrapper that contains an nsThread object because if nsIRunnable objects with
+ * a delay were dispatch directly to an nsThread object, such as obtained from
+ * nsThreadManager::GetCurrentThread(), the nsIRunnable could get stuck in the
+ * nsThread nsIRunnable queue. This is due to the fact that Android controls the
+ * event loop in the Android UI thread and has no knowledge of when the nsThread
+ * needs to be drained.
+ */
+
+class AndroidUiThread : public nsThread {
+ public:
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(AndroidUiThread, nsThread)
+  AndroidUiThread()
+      : nsThread(
+            MakeNotNull<ThreadEventQueue*>(MakeUnique<mozilla::EventQueue>()),
+            nsThread::NOT_MAIN_THREAD, {.stackSize = 0}) {}
+
+  nsresult Dispatch(already_AddRefed<nsIRunnable> aEvent,
+                    uint32_t aFlags) override;
+  nsresult DelayedDispatch(already_AddRefed<nsIRunnable> aEvent,
+                           uint32_t aDelayMs) override;
+
+ private:
+  ~AndroidUiThread() {}
+};
+
+NS_IMETHODIMP
+AndroidUiThread::Dispatch(already_AddRefed<nsIRunnable> aEvent,
+                          uint32_t aFlags) {
+  EnqueueTask(std::move(aEvent), 0);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+AndroidUiThread::DelayedDispatch(already_AddRefed<nsIRunnable> aEvent,
+                                 uint32_t aDelayMs) {
+  EnqueueTask(std::move(aEvent), aDelayMs);
+  return NS_OK;
+}
+
+static void PumpEvents() { NS_ProcessPendingEvents(sThread.get()); }
+
+class ThreadObserver : public nsIThreadObserver {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSITHREADOBSERVER
+
+  ThreadObserver() {}
+
+ private:
+  virtual ~ThreadObserver() {}
+};
+
+NS_IMPL_ISUPPORTS(ThreadObserver, nsIThreadObserver)
+
+NS_IMETHODIMP
+ThreadObserver::OnDispatchedEvent() {
+  EnqueueTask(NS_NewRunnableFunction("PumpEvents", &PumpEvents), 0);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ThreadObserver::OnProcessNextEvent(nsIThreadInternal* thread, bool mayWait) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ThreadObserver::AfterProcessNextEvent(nsIThreadInternal* thread,
+                                      bool eventWasProcessed) {
+  return NS_OK;
+}
+
+class AndroidUiTask : public LinkedListElement<AndroidUiTask> {
+  using TimeStamp = mozilla::TimeStamp;
+  using TimeDuration = mozilla::TimeDuration;
+
+ public:
+  explicit AndroidUiTask(already_AddRefed<nsIRunnable> aTask)
+      : mTask(aTask),
+        mRunTime()  // Null timestamp representing no delay.
+  {}
+
+  AndroidUiTask(already_AddRefed<nsIRunnable> aTask, int aDelayMs)
+      : mTask(aTask),
+        mRunTime(TimeStamp::Now() + TimeDuration::FromMilliseconds(aDelayMs)) {}
+
+  bool IsEarlierThan(const AndroidUiTask& aOther) const {
+    if (mRunTime) {
+      return aOther.mRunTime ? mRunTime < aOther.mRunTime : false;
+    }
+    // In the case of no delay, we're earlier if aOther has a delay.
+    // Otherwise, we're not earlier, to maintain task order.
+    return !!aOther.mRunTime;
+  }
+
+  int64_t MillisecondsToRunTime() const {
+    if (mRunTime) {
+      return int64_t((mRunTime - TimeStamp::Now()).ToMilliseconds());
+    }
+    return 0;
+  }
+
+  already_AddRefed<nsIRunnable> TakeTask() { return mTask.forget(); }
+
+ private:
+  nsCOMPtr<nsIRunnable> mTask;
+  const TimeStamp mRunTime;
+};
+
+class CreateOnUiThread : public Runnable {
+ public:
+  CreateOnUiThread() : Runnable("CreateOnUiThread") {}
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(!sThreadDestroyed);
+    MOZ_ASSERT(sMessageLoopAccessMonitor);
+    MonitorAutoLock lock(*sMessageLoopAccessMonitor);
+    sThread = new AndroidUiThread();
+    sThread->InitCurrentThread();
+    sThread->SetObserver(new ThreadObserver());
+    RegisterThreadWithProfiler();
+    sMessageLoop =
+        new MessageLoop(MessageLoop::TYPE_MOZILLA_ANDROID_UI, sThread.get());
+    lock.NotifyAll();
+    return NS_OK;
+  }
+
+ private:
+  static void RegisterThreadWithProfiler() {
+#if defined(MOZ_GECKO_PROFILER)
+    // We don't use the PROFILER_REGISTER_THREAD macro here because by this
+    // point the Android UI thread is already quite a ways into its stack;
+    // the profiler's sampler thread will ignore a lot of frames if we do not
+    // provide a better value for the stack top. We'll manually obtain that
+    // info via pthreads.
+
+    // Fallback address if any pthread calls fail
+    char fallback;
+    char* stackTop = &fallback;
+
+    auto regOnExit = MakeScopeExit(
+        [&stackTop]() { profiler_register_thread("AndroidUI", stackTop); });
+
+    pthread_attr_t attrs;
+    if (pthread_getattr_np(pthread_self(), &attrs)) {
+      return;
+    }
+
+    void* stackBase;
+    size_t stackSize;
+    if (pthread_attr_getstack(&attrs, &stackBase, &stackSize)) {
+      return;
+    }
+
+    stackTop = static_cast<char*>(stackBase) + stackSize - 1;
+#endif  // defined(MOZ_GECKO_PROFILER)
+  }
+};
+
+class DestroyOnUiThread : public Runnable {
+ public:
+  DestroyOnUiThread() : Runnable("DestroyOnUiThread"), mDestroyed(false) {}
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(!sThreadDestroyed);
+    MOZ_ASSERT(sMessageLoopAccessMonitor);
+    MOZ_ASSERT(sTaskQueue);
+    MonitorAutoLock lock(*sMessageLoopAccessMonitor);
+    sThreadDestroyed = true;
+
+    {
+      // Flush the queue
+      MutexAutoLock lock(*sTaskQueueLock);
+      while (AndroidUiTask* task = sTaskQueue->getFirst()) {
+        delete task;
+      }
+    }
+
+    delete sMessageLoop;
+    sMessageLoop = nullptr;
+    MOZ_ASSERT(sThread);
+    PROFILER_UNREGISTER_THREAD();
+    nsThreadManager::get().UnregisterCurrentThread(*sThread);
+    sThread = nullptr;
+    mDestroyed = true;
+    lock.NotifyAll();
+    return NS_OK;
+  }
+
+  void WaitForDestruction() {
+    MOZ_ASSERT(sMessageLoopAccessMonitor);
+    MonitorAutoLock lock(*sMessageLoopAccessMonitor);
+    while (!mDestroyed) {
+      lock.Wait();
+    }
+  }
+
+ private:
+  bool mDestroyed;
+};
+
+void EnqueueTask(already_AddRefed<nsIRunnable> aTask, int aDelayMs) {
+  if (sThreadDestroyed) {
+    return;
+  }
+
+  // add the new task into the sTaskQueue, sorted with
+  // the earliest task first in the queue
+  AndroidUiTask* newTask =
+      (aDelayMs ? new AndroidUiTask(std::move(aTask), aDelayMs)
+                : new AndroidUiTask(std::move(aTask)));
+
+  bool headOfList = false;
+  {
+    MOZ_ASSERT(sTaskQueue);
+    MOZ_ASSERT(sTaskQueueLock);
+    MutexAutoLock lock(*sTaskQueueLock);
+
+    AndroidUiTask* task = sTaskQueue->getFirst();
+
+    while (task) {
+      if (newTask->IsEarlierThan(*task)) {
+        task->setPrevious(newTask);
+        break;
+      }
+      task = task->getNext();
+    }
+
+    if (!newTask->isInList()) {
+      sTaskQueue->insertBack(newTask);
+    }
+    headOfList = !newTask->getPrevious();
+  }
+
+  if (headOfList) {
+    // if we're inserting it at the head of the queue, notify Java because
+    // we need to get a callback at an earlier time than the last scheduled
+    // callback
+    java::GeckoThread::RequestUiThreadCallback(int64_t(aDelayMs));
+  }
+}
+
+}  // namespace
+
+namespace mozilla {
+
+void CreateAndroidUiThread() {
+  MOZ_ASSERT(!sThread);
+  MOZ_ASSERT(!sMessageLoopAccessMonitor);
+  sTaskQueue = new LinkedList<AndroidUiTask>();
+  sTaskQueueLock = new Mutex("AndroidUiThreadTaskQueueLock");
+  sMessageLoopAccessMonitor =
+      new Monitor("AndroidUiThreadMessageLoopAccessMonitor");
+  sThreadDestroyed = false;
+  RefPtr<CreateOnUiThread> runnable = new CreateOnUiThread;
+  EnqueueTask(do_AddRef(runnable), 0);
+}
+
+void DestroyAndroidUiThread() {
+  MOZ_ASSERT(sThread);
+  RefPtr<DestroyOnUiThread> runnable = new DestroyOnUiThread;
+  EnqueueTask(do_AddRef(runnable), 0);
+  runnable->WaitForDestruction();
+  delete sMessageLoopAccessMonitor;
+  sMessageLoopAccessMonitor = nullptr;
+}
+
+MessageLoop* GetAndroidUiThreadMessageLoop() {
+  if (!sMessageLoopAccessMonitor) {
+    return nullptr;
+  }
+
+  MonitorAutoLock lock(*sMessageLoopAccessMonitor);
+  while (!sMessageLoop) {
+    lock.Wait();
+  }
+
+  return sMessageLoop;
+}
+
+RefPtr<nsThread> GetAndroidUiThread() {
+  if (!sMessageLoopAccessMonitor) {
+    return nullptr;
+  }
+
+  MonitorAutoLock lock(*sMessageLoopAccessMonitor);
+  while (!sThread) {
+    lock.Wait();
+  }
+
+  return sThread;
+}
+
+int64_t RunAndroidUiTasks() {
+  MutexAutoLock lock(*sTaskQueueLock);
+
+  if (sThreadDestroyed) {
+    return -1;
+  }
+
+  while (!sTaskQueue->isEmpty()) {
+    AndroidUiTask* task = sTaskQueue->getFirst();
+    const int64_t timeLeft = task->MillisecondsToRunTime();
+    if (timeLeft > 0) {
+      // this task (and therefore all remaining tasks)
+      // have not yet reached their runtime. return the
+      // time left until we should be called again
+      return timeLeft;
+    }
+
+    // Retrieve task before unlocking/running.
+    nsCOMPtr<nsIRunnable> runnable(task->TakeTask());
+    // LinkedListElements auto remove from list upon destruction
+    delete task;
+
+    // Unlock to allow posting new tasks reentrantly.
+    MutexAutoUnlock unlock(*sTaskQueueLock);
+    runnable->Run();
+    if (sThreadDestroyed) {
+      return -1;
+    }
+  }
+  return -1;
+}
+
+}  // namespace mozilla
diff --git a/widget/android/AndroidUiThread.h b/widget/android/AndroidUiThread.h
new file mode 100644
index 0000000000..af722fb048
--- /dev/null
+++ b/widget/android/AndroidUiThread.h
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef AndroidUiThread_h__
+#define AndroidUiThread_h__
+
+#include <mozilla/RefPtr.h>
+#include <nsThread.h>
+
+class MessageLoop;
+
+namespace mozilla {
+
+void CreateAndroidUiThread();
+void DestroyAndroidUiThread();
+int64_t RunAndroidUiTasks();
+
+MessageLoop* GetAndroidUiThreadMessageLoop();
+RefPtr<nsThread> GetAndroidUiThread();
+
+}  // namespace mozilla
+
+#endif  // AndroidUiThread_h__
diff --git a/widget/android/AndroidView.h b/widget/android/AndroidView.h
new file mode 100644
index 0000000000..173db8b5c1
--- /dev/null
+++ b/widget/android/AndroidView.h
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_AndroidView_h
+#define mozilla_widget_AndroidView_h
+
+#include "mozilla/widget/EventDispatcher.h"
+
+namespace mozilla {
+namespace widget {
+
+class AndroidView final : public nsIAndroidView {
+  virtual ~AndroidView() {}
+
+ public:
+  const RefPtr<mozilla::widget::EventDispatcher> mEventDispatcher{
+      new mozilla::widget::EventDispatcher()};
+
+  AndroidView() {}
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIANDROIDVIEW
+
+  NS_FORWARD_NSIANDROIDEVENTDISPATCHER(mEventDispatcher->)
+
+  mozilla::java::GeckoBundle::GlobalRef mInitData;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_AndroidView_h
diff --git a/widget/android/AndroidVsync.cpp b/widget/android/AndroidVsync.cpp
new file mode 100644
index 0000000000..6aed5f1e53
--- /dev/null
+++ b/widget/android/AndroidVsync.cpp
@@ -0,0 +1,150 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AndroidVsync.h"
+
+#include "AndroidBridge.h"
+#include "nsTArray.h"
+
+/**
+ * Implementation for the AndroidVsync class.
+ */
+
+namespace mozilla {
+namespace widget {
+
+StaticDataMutex<ThreadSafeWeakPtr<AndroidVsync>> AndroidVsync::sInstance(
+    "AndroidVsync::sInstance");
+
+/* static */ RefPtr<AndroidVsync> AndroidVsync::GetInstance() {
+  auto weakInstance = sInstance.Lock();
+  RefPtr<AndroidVsync> instance(*weakInstance);
+  if (!instance) {
+    instance = new AndroidVsync();
+    *weakInstance = instance;
+  }
+  return instance;
+}
+
+/**
+ * Owned by the Java AndroidVsync instance.
+ */
+class AndroidVsyncSupport final
+    : public java::AndroidVsync::Natives<AndroidVsyncSupport> {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AndroidVsyncSupport)
+
+  using Base = java::AndroidVsync::Natives<AndroidVsyncSupport>;
+  using Base::AttachNative;
+  using Base::DisposeNative;
+
+  explicit AndroidVsyncSupport(AndroidVsync* aAndroidVsync)
+      : mAndroidVsync(std::move(aAndroidVsync),
+                      "AndroidVsyncSupport::mAndroidVsync") {}
+
+  // Called by Java
+  void NotifyVsync(const java::AndroidVsync::LocalRef& aInstance,
+                   int64_t aFrameTimeNanos) {
+    auto androidVsync = mAndroidVsync.Lock();
+    if (*androidVsync) {
+      (*androidVsync)->NotifyVsync(aFrameTimeNanos);
+    }
+  }
+
+  // Called by the AndroidVsync destructor
+  void Unlink() {
+    auto androidVsync = mAndroidVsync.Lock();
+    *androidVsync = nullptr;
+  }
+
+ protected:
+  ~AndroidVsyncSupport() = default;
+
+  DataMutex<AndroidVsync*> mAndroidVsync;
+};
+
+AndroidVsync::AndroidVsync() : mImpl("AndroidVsync.mImpl") {
+  AndroidVsyncSupport::Init();
+
+  auto impl = mImpl.Lock();
+  impl->mSupport = new AndroidVsyncSupport(this);
+  impl->mSupportJava = java::AndroidVsync::New();
+  AndroidVsyncSupport::AttachNative(impl->mSupportJava, impl->mSupport);
+}
+
+AndroidVsync::~AndroidVsync() {
+  auto impl = mImpl.Lock();
+  impl->mInputObservers.Clear();
+  impl->mRenderObservers.Clear();
+  impl->UpdateObservingVsync();
+  impl->mSupport->Unlink();
+}
+
+void AndroidVsync::RegisterObserver(Observer* aObserver, ObserverType aType) {
+  auto impl = mImpl.Lock();
+  if (aType == AndroidVsync::INPUT) {
+    impl->mInputObservers.AppendElement(aObserver);
+  } else {
+    impl->mRenderObservers.AppendElement(aObserver);
+  }
+  impl->UpdateObservingVsync();
+}
+
+void AndroidVsync::UnregisterObserver(Observer* aObserver, ObserverType aType) {
+  auto impl = mImpl.Lock();
+  if (aType == AndroidVsync::INPUT) {
+    impl->mInputObservers.RemoveElement(aObserver);
+  } else {
+    impl->mRenderObservers.RemoveElement(aObserver);
+  }
+  aObserver->Dispose();
+  impl->UpdateObservingVsync();
+}
+
+void AndroidVsync::Impl::UpdateObservingVsync() {
+  bool shouldObserve =
+      !mInputObservers.IsEmpty() || !mRenderObservers.IsEmpty();
+  if (shouldObserve != mObservingVsync) {
+    mObservingVsync = mSupportJava->ObserveVsync(shouldObserve);
+  }
+}
+
+// Always called on the Java UI thread.
+void AndroidVsync::NotifyVsync(int64_t aFrameTimeNanos) {
+  MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+
+  // Convert aFrameTimeNanos to a TimeStamp. The value converts trivially to
+  // the internal ticks representation of TimeStamp_posix; both use the
+  // monotonic clock and are in nanoseconds.
+  TimeStamp timeStamp = TimeStamp::FromSystemTime(aFrameTimeNanos);
+
+  // Do not keep the lock held while calling OnVsync.
+  nsTArray<Observer*> observers;
+  {
+    auto impl = mImpl.Lock();
+    observers.AppendElements(impl->mInputObservers);
+    observers.AppendElements(impl->mRenderObservers);
+  }
+  for (Observer* observer : observers) {
+    observer->OnVsync(timeStamp);
+  }
+}
+
+void AndroidVsync::OnMaybeUpdateRefreshRate() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  auto impl = mImpl.Lock();
+
+  nsTArray<Observer*> observers;
+  observers.AppendElements(impl->mRenderObservers);
+
+  for (Observer* observer : observers) {
+    observer->OnMaybeUpdateRefreshRate();
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/AndroidVsync.h b/widget/android/AndroidVsync.h
new file mode 100644
index 0000000000..d50e1ec71f
--- /dev/null
+++ b/widget/android/AndroidVsync.h
@@ -0,0 +1,79 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_AndroidVsync_h
+#define mozilla_widget_AndroidVsync_h
+
+#include "mozilla/DataMutex.h"
+#include "mozilla/java/AndroidVsyncNatives.h"
+#include "mozilla/ThreadSafeWeakPtr.h"
+#include "mozilla/TimeStamp.h"
+
+namespace mozilla {
+namespace widget {
+
+class AndroidVsyncSupport;
+
+/**
+ * A thread-safe way to listen to vsync notifications on Android. All methods
+ * can be called on any thread.
+ * Observers must keep a strong reference to the AndroidVsync instance until
+ * they unregister themselves.
+ */
+class AndroidVsync final : public SupportsThreadSafeWeakPtr<AndroidVsync> {
+ public:
+  MOZ_DECLARE_REFCOUNTED_TYPENAME(AndroidVsync)
+
+  static RefPtr<AndroidVsync> GetInstance();
+
+  ~AndroidVsync();
+
+  class Observer {
+   public:
+    // Will be called on the Java UI thread.
+    virtual void OnVsync(const TimeStamp& aTimeStamp) = 0;
+    // Will be called on the Java UI thread.
+    virtual void OnMaybeUpdateRefreshRate() {}
+    // Called when the observer is unregistered, in case it wants to
+    // manage its own lifetime.
+    virtual void Dispose() {}
+    virtual ~Observer() = default;
+  };
+
+  // INPUT observers are called before RENDER observers.
+  enum ObserverType { INPUT, RENDER };
+  void RegisterObserver(Observer* aObserver, ObserverType aType);
+  void UnregisterObserver(Observer* aObserver, ObserverType aType);
+
+  void OnMaybeUpdateRefreshRate();
+
+ private:
+  friend class AndroidVsyncSupport;
+
+  AndroidVsync();
+
+  // Called by Java, via AndroidVsyncSupport
+  void NotifyVsync(int64_t aFrameTimeNanos);
+
+  struct Impl {
+    void UpdateObservingVsync();
+
+    nsTArray<Observer*> mInputObservers;
+    nsTArray<Observer*> mRenderObservers;
+    RefPtr<AndroidVsyncSupport> mSupport;
+    java::AndroidVsync::GlobalRef mSupportJava;
+    bool mObservingVsync = false;
+  };
+
+  DataMutex<Impl> mImpl;
+
+  static StaticDataMutex<ThreadSafeWeakPtr<AndroidVsync>> sInstance;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_AndroidVsync_h
diff --git a/widget/android/AndroidWidgetUtils.cpp b/widget/android/AndroidWidgetUtils.cpp
new file mode 100644
index 0000000000..c013a5b4f8
--- /dev/null
+++ b/widget/android/AndroidWidgetUtils.cpp
@@ -0,0 +1,48 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * vim: set sw=2 ts=4 expandtab:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AndroidWidgetUtils.h"
+
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Swizzle.h"
+
+using namespace mozilla::gfx;
+
+namespace mozilla::widget {
+
+// static
+already_AddRefed<DataSourceSurface>
+AndroidWidgetUtils::GetDataSourceSurfaceForAndroidBitmap(
+    gfx::SourceSurface* aSurface, const LayoutDeviceIntRect* aRect,
+    uint32_t aStride) {
+  RefPtr<DataSourceSurface> srcDataSurface = aSurface->GetDataSurface();
+  if (NS_WARN_IF(!srcDataSurface)) {
+    return nullptr;
+  }
+
+  DataSourceSurface::ScopedMap sourceMap(srcDataSurface,
+                                         DataSourceSurface::READ);
+
+  RefPtr<DataSourceSurface> destDataSurface =
+      gfx::Factory::CreateDataSourceSurfaceWithStride(
+          aRect ? IntSize(aRect->width, aRect->height)
+                : srcDataSurface->GetSize(),
+          SurfaceFormat::R8G8B8A8, aStride ? aStride : sourceMap.GetStride());
+  if (NS_WARN_IF(!destDataSurface)) {
+    return nullptr;
+  }
+
+  DataSourceSurface::ScopedMap destMap(destDataSurface,
+                                       DataSourceSurface::READ_WRITE);
+
+  SwizzleData(sourceMap.GetData(), sourceMap.GetStride(), aSurface->GetFormat(),
+              destMap.GetData(), destMap.GetStride(), SurfaceFormat::R8G8B8A8,
+              destDataSurface->GetSize());
+
+  return destDataSurface.forget();
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/android/AndroidWidgetUtils.h b/widget/android/AndroidWidgetUtils.h
new file mode 100644
index 0000000000..ccf831206d
--- /dev/null
+++ b/widget/android/AndroidWidgetUtils.h
@@ -0,0 +1,37 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * vim: set sw=2 ts=4 expandtab:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_AndroidWidgetUtils_h__
+#define mozilla_widget_AndroidWidgetUtils_h__
+
+#include "Units.h"
+
+namespace mozilla {
+
+namespace gfx {
+class SourceSurface;
+class DataSourceSurface;
+}  // namespace gfx
+
+namespace widget {
+
+class AndroidWidgetUtils final {
+ public:
+  typedef mozilla::LayoutDeviceIntRect LayoutDeviceIntRect;
+
+  /**
+   * Return Android's bitmap object compatible data surface.
+   */
+  static already_AddRefed<gfx::DataSourceSurface>
+  GetDataSourceSurfaceForAndroidBitmap(
+      gfx::SourceSurface* aSurface, const LayoutDeviceIntRect* aRect = nullptr,
+      uint32_t aStride = 0);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/android/Base64UtilsSupport.h b/widget/android/Base64UtilsSupport.h
new file mode 100644
index 0000000000..8ac4347aaa
--- /dev/null
+++ b/widget/android/Base64UtilsSupport.h
@@ -0,0 +1,52 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef Base64UtilsSupport_h__
+#define Base64UtilsSupport_h__
+
+#include "mozilla/Base64.h"
+#include "mozilla/java/Base64UtilsNatives.h"
+
+namespace mozilla {
+namespace widget {
+
+class Base64UtilsSupport final
+    : public java::Base64Utils::Natives<Base64UtilsSupport> {
+ public:
+  static jni::ByteArray::LocalRef Decode(jni::String::Param data) {
+    if (!data) {
+      return nullptr;
+    }
+
+    FallibleTArray<uint8_t> bytes;
+    if (NS_FAILED(Base64URLDecode(
+            data->ToCString(), Base64URLDecodePaddingPolicy::Ignore, bytes))) {
+      return nullptr;
+    }
+
+    return jni::ByteArray::New((const signed char*)bytes.Elements(),
+                               bytes.Length());
+  }
+
+  static jni::String::LocalRef Encode(jni::ByteArray::Param data) {
+    if (!data) {
+      return nullptr;
+    }
+
+    nsTArray<int8_t> bytes = data->GetElements();
+    nsCString result;
+    if (NS_FAILED(
+            Base64URLEncode(data->Length(), (const uint8_t*)bytes.Elements(),
+                            Base64URLEncodePaddingPolicy::Omit, result))) {
+      return nullptr;
+    }
+    return jni::StringParam(result);
+  }
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // Base64UtilsSupport_h__
diff --git a/widget/android/CompositorWidgetChild.cpp b/widget/android/CompositorWidgetChild.cpp
new file mode 100644
index 0000000000..ba51dda7a5
--- /dev/null
+++ b/widget/android/CompositorWidgetChild.cpp
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CompositorWidgetChild.h"
+#include "mozilla/Unused.h"
+#include "gfxPlatform.h"
+
+namespace mozilla {
+namespace widget {
+
+CompositorWidgetChild::CompositorWidgetChild(
+    RefPtr<CompositorVsyncDispatcher> aVsyncDispatcher,
+    RefPtr<CompositorWidgetVsyncObserver> aVsyncObserver,
+    const CompositorWidgetInitData&)
+    : mVsyncDispatcher(aVsyncDispatcher), mVsyncObserver(aVsyncObserver) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(!gfxPlatform::IsHeadless());
+}
+
+CompositorWidgetChild::~CompositorWidgetChild() = default;
+
+bool CompositorWidgetChild::Initialize() { return true; }
+
+mozilla::ipc::IPCResult CompositorWidgetChild::RecvObserveVsync() {
+  mVsyncDispatcher->SetCompositorVsyncObserver(mVsyncObserver);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult CompositorWidgetChild::RecvUnobserveVsync() {
+  mVsyncDispatcher->SetCompositorVsyncObserver(nullptr);
+  return IPC_OK();
+}
+
+void CompositorWidgetChild::NotifyClientSizeChanged(
+    const LayoutDeviceIntSize& aClientSize) {
+  Unused << SendNotifyClientSizeChanged(aClientSize);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/CompositorWidgetChild.h b/widget/android/CompositorWidgetChild.h
new file mode 100644
index 0000000000..88cb2913e9
--- /dev/null
+++ b/widget/android/CompositorWidgetChild.h
@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_android_CompositorWidgetChild_h
+#define widget_android_CompositorWidgetChild_h
+
+#include "AndroidCompositorWidget.h"
+#include "mozilla/widget/PCompositorWidgetChild.h"
+#include "mozilla/widget/CompositorWidgetVsyncObserver.h"
+
+namespace mozilla {
+namespace widget {
+
+class CompositorWidgetChild final : public PCompositorWidgetChild,
+                                    public PlatformCompositorWidgetDelegate {
+ public:
+  CompositorWidgetChild(RefPtr<CompositorVsyncDispatcher> aVsyncDispatcher,
+                        RefPtr<CompositorWidgetVsyncObserver> aVsyncObserver,
+                        const CompositorWidgetInitData&);
+  ~CompositorWidgetChild() override;
+
+  bool Initialize();
+
+  mozilla::ipc::IPCResult RecvObserveVsync() override;
+  mozilla::ipc::IPCResult RecvUnobserveVsync() override;
+
+  // PlatformCompositorWidgetDelegate overrides
+
+  void NotifyClientSizeChanged(const LayoutDeviceIntSize& aClientSize) override;
+
+ private:
+  RefPtr<CompositorVsyncDispatcher> mVsyncDispatcher;
+  RefPtr<CompositorWidgetVsyncObserver> mVsyncObserver;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_android_CompositorWidgetChild_h
diff --git a/widget/android/CompositorWidgetParent.cpp b/widget/android/CompositorWidgetParent.cpp
new file mode 100644
index 0000000000..93b87f3cd3
--- /dev/null
+++ b/widget/android/CompositorWidgetParent.cpp
@@ -0,0 +1,54 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CompositorWidgetParent.h"
+#include "mozilla/Unused.h"
+#include "mozilla/java/GeckoServiceGpuProcessWrappers.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+
+namespace mozilla {
+namespace widget {
+
+CompositorWidgetParent::CompositorWidgetParent(
+    const CompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions)
+    : AndroidCompositorWidget(aInitData.get_AndroidCompositorWidgetInitData(),
+                              aOptions) {
+  MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_GPU);
+}
+
+CompositorWidgetParent::~CompositorWidgetParent() = default;
+
+nsIWidget* CompositorWidgetParent::RealWidget() { return nullptr; }
+
+void CompositorWidgetParent::ObserveVsync(VsyncObserver* aObserver) {
+  if (aObserver) {
+    Unused << SendObserveVsync();
+  } else {
+    Unused << SendUnobserveVsync();
+  }
+  mVsyncObserver = aObserver;
+}
+
+RefPtr<VsyncObserver> CompositorWidgetParent::GetVsyncObserver() const {
+  MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_GPU);
+  return mVsyncObserver;
+}
+
+mozilla::ipc::IPCResult CompositorWidgetParent::RecvNotifyClientSizeChanged(
+    const LayoutDeviceIntSize& aClientSize) {
+  NotifyClientSizeChanged(aClientSize);
+  return IPC_OK();
+}
+
+void CompositorWidgetParent::OnCompositorSurfaceChanged() {
+  java::GeckoServiceGpuProcess::RemoteCompositorSurfaceManager::LocalRef
+      manager = java::GeckoServiceGpuProcess::RemoteCompositorSurfaceManager::
+          GetInstance();
+  mSurface = manager->GetCompositorSurface(mWidgetId);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/CompositorWidgetParent.h b/widget/android/CompositorWidgetParent.h
new file mode 100644
index 0000000000..cd6e4241ca
--- /dev/null
+++ b/widget/android/CompositorWidgetParent.h
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_android_CompositorWidgetParent_h
+#define widget_android_CompositorWidgetParent_h
+
+#include "AndroidCompositorWidget.h"
+#include "mozilla/VsyncDispatcher.h"
+#include "mozilla/widget/PCompositorWidgetParent.h"
+
+namespace mozilla {
+namespace widget {
+
+class CompositorWidgetParent final : public PCompositorWidgetParent,
+                                     public AndroidCompositorWidget {
+ public:
+  explicit CompositorWidgetParent(const CompositorWidgetInitData& aInitData,
+                                  const layers::CompositorOptions& aOptions);
+  ~CompositorWidgetParent() override;
+
+  // CompositorWidget overrides
+
+  nsIWidget* RealWidget() override;
+  void ObserveVsync(VsyncObserver* aObserver) override;
+  RefPtr<VsyncObserver> GetVsyncObserver() const override;
+
+  mozilla::ipc::IPCResult RecvNotifyClientSizeChanged(
+      const LayoutDeviceIntSize& aClientSize) override;
+
+ private:
+  // AndroidCompositorWidget overrides
+  void OnCompositorSurfaceChanged() override;
+
+  RefPtr<VsyncObserver> mVsyncObserver;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_android_CompositorWidgetParent_h
diff --git a/widget/android/EventDispatcher.cpp b/widget/android/EventDispatcher.cpp
new file mode 100644
index 0000000000..ab876de136
--- /dev/null
+++ b/widget/android/EventDispatcher.cpp
@@ -0,0 +1,776 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * vim: set sw=2 ts=4 expandtab:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "EventDispatcher.h"
+
+#include "JavaBuiltins.h"
+#include "nsAppShell.h"
+#include "nsJSUtils.h"
+#include "js/Array.h"  // JS::GetArrayLength, JS::IsArrayObject, JS::NewArrayObject
+#include "js/PropertyAndElement.h"  // JS_Enumerate, JS_GetElement, JS_GetProperty, JS_GetPropertyById, JS_SetElement, JS_SetUCProperty
+#include "js/String.h"              // JS::StringHasLatin1Chars
+#include "js/Warnings.h"            // JS::WarnUTF8
+#include "xpcpublic.h"
+
+#include "mozilla/fallible.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/java/EventCallbackWrappers.h"
+#include "mozilla/jni/GeckoBundleUtils.h"
+
+// Disable the C++ 2a warning. See bug #1509926
+#if defined(__clang__)
+#  pragma clang diagnostic push
+#  pragma clang diagnostic ignored "-Wc++2a-compat"
+#endif
+
+namespace mozilla {
+namespace widget {
+
+namespace detail {
+
+bool CheckJS(JSContext* aCx, bool aResult) {
+  if (!aResult) {
+    JS_ClearPendingException(aCx);
+  }
+  return aResult;
+}
+
+nsresult BoxData(const nsAString& aEvent, JSContext* aCx,
+                 JS::Handle<JS::Value> aData, jni::Object::LocalRef& aOut,
+                 bool aObjectOnly) {
+  nsresult rv = jni::BoxData(aCx, aData, aOut, aObjectOnly);
+  if (rv != NS_ERROR_INVALID_ARG) {
+    return rv;
+  }
+
+  NS_ConvertUTF16toUTF8 event(aEvent);
+  if (JS_IsExceptionPending(aCx)) {
+    JS::WarnUTF8(aCx, "Error dispatching %s", event.get());
+  } else {
+    JS_ReportErrorUTF8(aCx, "Invalid event data for %s", event.get());
+  }
+  return NS_ERROR_INVALID_ARG;
+}
+
+nsresult UnboxString(JSContext* aCx, const jni::Object::LocalRef& aData,
+                     JS::MutableHandle<JS::Value> aOut) {
+  if (!aData) {
+    aOut.setNull();
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(aData.IsInstanceOf<jni::String>());
+
+  JNIEnv* const env = aData.Env();
+  const jstring jstr = jstring(aData.Get());
+  const size_t len = env->GetStringLength(jstr);
+  const jchar* const jchars = env->GetStringChars(jstr, nullptr);
+
+  if (NS_WARN_IF(!jchars)) {
+    env->ExceptionClear();
+    return NS_ERROR_FAILURE;
+  }
+
+  auto releaseStr = MakeScopeExit([env, jstr, jchars] {
+    env->ReleaseStringChars(jstr, jchars);
+    env->ExceptionClear();
+  });
+
+  JS::Rooted<JSString*> str(
+      aCx,
+      JS_NewUCStringCopyN(aCx, reinterpret_cast<const char16_t*>(jchars), len));
+  NS_ENSURE_TRUE(CheckJS(aCx, !!str), NS_ERROR_FAILURE);
+
+  aOut.setString(str);
+  return NS_OK;
+}
+
+nsresult UnboxValue(JSContext* aCx, const jni::Object::LocalRef& aData,
+                    JS::MutableHandle<JS::Value> aOut);
+
+nsresult UnboxBundle(JSContext* aCx, const jni::Object::LocalRef& aData,
+                     JS::MutableHandle<JS::Value> aOut) {
+  if (!aData) {
+    aOut.setNull();
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(aData.IsInstanceOf<java::GeckoBundle>());
+
+  JNIEnv* const env = aData.Env();
+  const auto& bundle = java::GeckoBundle::Ref::From(aData);
+  jni::ObjectArray::LocalRef keys = bundle->Keys();
+  jni::ObjectArray::LocalRef values = bundle->Values();
+  const size_t len = keys->Length();
+  JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+
+  NS_ENSURE_TRUE(CheckJS(aCx, !!obj), NS_ERROR_FAILURE);
+  NS_ENSURE_TRUE(values->Length() == len, NS_ERROR_FAILURE);
+
+  for (size_t i = 0; i < len; i++) {
+    jni::String::LocalRef key = keys->GetElement(i);
+    const size_t keyLen = env->GetStringLength(key.Get());
+    const jchar* const keyChars = env->GetStringChars(key.Get(), nullptr);
+    if (NS_WARN_IF(!keyChars)) {
+      env->ExceptionClear();
+      return NS_ERROR_FAILURE;
+    }
+
+    auto releaseKeyChars = MakeScopeExit([env, &key, keyChars] {
+      env->ReleaseStringChars(key.Get(), keyChars);
+      env->ExceptionClear();
+    });
+
+    JS::Rooted<JS::Value> value(aCx);
+    nsresult rv = UnboxValue(aCx, values->GetElement(i), &value);
+    if (rv == NS_ERROR_INVALID_ARG && !JS_IsExceptionPending(aCx)) {
+      JS_ReportErrorUTF8(
+          aCx, u8"Invalid event data property %s",
+          NS_ConvertUTF16toUTF8(
+              nsString(reinterpret_cast<const char16_t*>(keyChars), keyLen))
+              .get());
+    }
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    NS_ENSURE_TRUE(
+        CheckJS(aCx, JS_SetUCProperty(
+                         aCx, obj, reinterpret_cast<const char16_t*>(keyChars),
+                         keyLen, value)),
+        NS_ERROR_FAILURE);
+  }
+
+  aOut.setObject(*obj);
+  return NS_OK;
+}
+
+template <typename Type, typename JNIType, typename ArrayType,
+          JNIType* (JNIEnv::*GetElements)(ArrayType, jboolean*),
+          void (JNIEnv::*ReleaseElements)(ArrayType, JNIType*, jint),
+          JS::Value (*ToValue)(Type)>
+nsresult UnboxArrayPrimitive(JSContext* aCx, const jni::Object::LocalRef& aData,
+                             JS::MutableHandle<JS::Value> aOut) {
+  JNIEnv* const env = aData.Env();
+  const ArrayType jarray = ArrayType(aData.Get());
+  JNIType* const array = (env->*GetElements)(jarray, nullptr);
+  JS::RootedVector<JS::Value> elements(aCx);
+
+  if (NS_WARN_IF(!array)) {
+    env->ExceptionClear();
+    return NS_ERROR_FAILURE;
+  }
+
+  auto releaseArray = MakeScopeExit([env, jarray, array] {
+    (env->*ReleaseElements)(jarray, array, JNI_ABORT);
+    env->ExceptionClear();
+  });
+
+  const size_t len = env->GetArrayLength(jarray);
+  NS_ENSURE_TRUE(elements.initCapacity(len), NS_ERROR_FAILURE);
+
+  for (size_t i = 0; i < len; i++) {
+    NS_ENSURE_TRUE(elements.append((*ToValue)(Type(array[i]))),
+                   NS_ERROR_FAILURE);
+  }
+
+  JS::Rooted<JSObject*> obj(
+      aCx, JS::NewArrayObject(aCx, JS::HandleValueArray(elements)));
+  NS_ENSURE_TRUE(CheckJS(aCx, !!obj), NS_ERROR_FAILURE);
+
+  aOut.setObject(*obj);
+  return NS_OK;
+}
+
+struct StringArray : jni::ObjectBase<StringArray> {
+  static const char name[];
+};
+
+struct GeckoBundleArray : jni::ObjectBase<GeckoBundleArray> {
+  static const char name[];
+};
+
+const char StringArray::name[] = "[Ljava/lang/String;";
+const char GeckoBundleArray::name[] = "[Lorg/mozilla/gecko/util/GeckoBundle;";
+
+template <nsresult (*Unbox)(JSContext*, const jni::Object::LocalRef&,
+                            JS::MutableHandle<JS::Value>)>
+nsresult UnboxArrayObject(JSContext* aCx, const jni::Object::LocalRef& aData,
+                          JS::MutableHandle<JS::Value> aOut) {
+  jni::ObjectArray::LocalRef array(aData.Env(),
+                                   jni::ObjectArray::Ref::From(aData));
+  const size_t len = array->Length();
+  JS::Rooted<JSObject*> obj(aCx, JS::NewArrayObject(aCx, len));
+  NS_ENSURE_TRUE(CheckJS(aCx, !!obj), NS_ERROR_FAILURE);
+
+  for (size_t i = 0; i < len; i++) {
+    jni::Object::LocalRef element = array->GetElement(i);
+    JS::Rooted<JS::Value> value(aCx);
+    nsresult rv = (*Unbox)(aCx, element, &value);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    NS_ENSURE_TRUE(CheckJS(aCx, JS_SetElement(aCx, obj, i, value)),
+                   NS_ERROR_FAILURE);
+  }
+
+  aOut.setObject(*obj);
+  return NS_OK;
+}
+
+nsresult UnboxValue(JSContext* aCx, const jni::Object::LocalRef& aData,
+                    JS::MutableHandle<JS::Value> aOut) {
+  using jni::Java2Native;
+
+  if (!aData) {
+    aOut.setNull();
+  } else if (aData.IsInstanceOf<jni::Boolean>()) {
+    aOut.setBoolean(Java2Native<bool>(aData, aData.Env()));
+  } else if (aData.IsInstanceOf<jni::Integer>()) {
+    aOut.setInt32(Java2Native<int>(aData, aData.Env()));
+  } else if (aData.IsInstanceOf<jni::Byte>() ||
+             aData.IsInstanceOf<jni::Short>()) {
+    aOut.setInt32(java::sdk::Number::Ref::From(aData)->IntValue());
+  } else if (aData.IsInstanceOf<jni::Double>()) {
+    aOut.setNumber(Java2Native<double>(aData, aData.Env()));
+  } else if (aData.IsInstanceOf<jni::Float>() ||
+             aData.IsInstanceOf<jni::Long>()) {
+    aOut.setNumber(java::sdk::Number::Ref::From(aData)->DoubleValue());
+  } else if (aData.IsInstanceOf<jni::String>()) {
+    return UnboxString(aCx, aData, aOut);
+  } else if (aData.IsInstanceOf<jni::Character>()) {
+    return UnboxString(aCx, java::sdk::String::ValueOf(aData), aOut);
+  } else if (aData.IsInstanceOf<java::GeckoBundle>()) {
+    return UnboxBundle(aCx, aData, aOut);
+
+  } else if (aData.IsInstanceOf<jni::BooleanArray>()) {
+    return UnboxArrayPrimitive<
+        bool, jboolean, jbooleanArray, &JNIEnv::GetBooleanArrayElements,
+        &JNIEnv::ReleaseBooleanArrayElements, &JS::BooleanValue>(aCx, aData,
+                                                                 aOut);
+
+  } else if (aData.IsInstanceOf<jni::IntArray>()) {
+    return UnboxArrayPrimitive<
+        int32_t, jint, jintArray, &JNIEnv::GetIntArrayElements,
+        &JNIEnv::ReleaseIntArrayElements, &JS::Int32Value>(aCx, aData, aOut);
+
+  } else if (aData.IsInstanceOf<jni::DoubleArray>()) {
+    return UnboxArrayPrimitive<
+        double, jdouble, jdoubleArray, &JNIEnv::GetDoubleArrayElements,
+        &JNIEnv::ReleaseDoubleArrayElements, &JS::DoubleValue>(aCx, aData,
+                                                               aOut);
+
+  } else if (aData.IsInstanceOf<StringArray>()) {
+    return UnboxArrayObject<&UnboxString>(aCx, aData, aOut);
+  } else if (aData.IsInstanceOf<GeckoBundleArray>()) {
+    return UnboxArrayObject<&UnboxBundle>(aCx, aData, aOut);
+  } else {
+    NS_WARNING("Invalid type");
+    return NS_ERROR_INVALID_ARG;
+  }
+  return NS_OK;
+}
+
+nsresult UnboxData(jni::String::Param aEvent, JSContext* aCx,
+                   jni::Object::Param aData, JS::MutableHandle<JS::Value> aOut,
+                   bool aBundleOnly) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  jni::Object::LocalRef jniData(jni::GetGeckoThreadEnv(), aData);
+  nsresult rv = NS_ERROR_INVALID_ARG;
+
+  if (!aBundleOnly) {
+    rv = UnboxValue(aCx, jniData, aOut);
+  } else if (!jniData || jniData.IsInstanceOf<java::GeckoBundle>()) {
+    rv = UnboxBundle(aCx, jniData, aOut);
+  }
+  if (rv != NS_ERROR_INVALID_ARG || !aEvent) {
+    return rv;
+  }
+
+  nsCString event = aEvent->ToCString();
+  if (JS_IsExceptionPending(aCx)) {
+    JS::WarnUTF8(aCx, "Error dispatching %s", event.get());
+  } else {
+    JS_ReportErrorUTF8(aCx, "Invalid event data for %s", event.get());
+  }
+  return NS_ERROR_INVALID_ARG;
+}
+
+class JavaCallbackDelegate final : public nsIAndroidEventCallback {
+  const java::EventCallback::GlobalRef mCallback;
+
+  virtual ~JavaCallbackDelegate() {}
+
+  NS_IMETHOD Call(JSContext* aCx, JS::Handle<JS::Value> aData,
+                  void (java::EventCallback::*aCall)(jni::Object::Param)
+                      const) {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    jni::Object::LocalRef data(jni::GetGeckoThreadEnv());
+    nsresult rv = BoxData(u"callback"_ns, aCx, aData, data,
+                          /* ObjectOnly */ false);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    dom::AutoNoJSAPI nojsapi;
+
+    (java::EventCallback(*mCallback).*aCall)(data);
+    return NS_OK;
+  }
+
+ public:
+  explicit JavaCallbackDelegate(java::EventCallback::Param aCallback)
+      : mCallback(jni::GetGeckoThreadEnv(), aCallback) {}
+
+  NS_DECL_ISUPPORTS
+
+  NS_IMETHOD OnSuccess(JS::Handle<JS::Value> aData, JSContext* aCx) override {
+    return Call(aCx, aData, &java::EventCallback::SendSuccess);
+  }
+
+  NS_IMETHOD OnError(JS::Handle<JS::Value> aData, JSContext* aCx) override {
+    return Call(aCx, aData, &java::EventCallback::SendError);
+  }
+};
+
+NS_IMPL_ISUPPORTS(JavaCallbackDelegate, nsIAndroidEventCallback)
+
+class NativeCallbackDelegateSupport final
+    : public java::EventDispatcher::NativeCallbackDelegate ::Natives<
+          NativeCallbackDelegateSupport> {
+  using CallbackDelegate = java::EventDispatcher::NativeCallbackDelegate;
+  using Base = CallbackDelegate::Natives<NativeCallbackDelegateSupport>;
+
+  const nsCOMPtr<nsIAndroidEventCallback> mCallback;
+  const nsCOMPtr<nsIAndroidEventFinalizer> mFinalizer;
+  const nsCOMPtr<nsIGlobalObject> mGlobalObject;
+
+  void Call(jni::Object::Param aData,
+            nsresult (nsIAndroidEventCallback::*aCall)(JS::Handle<JS::Value>,
+                                                       JSContext*)) {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    // Use either the attached window's realm or a default realm.
+
+    dom::AutoJSAPI jsapi;
+    NS_ENSURE_TRUE_VOID(jsapi.Init(mGlobalObject));
+
+    JS::Rooted<JS::Value> data(jsapi.cx());
+    nsresult rv = UnboxData(u"callback"_ns, jsapi.cx(), aData, &data,
+                            /* BundleOnly */ false);
+    NS_ENSURE_SUCCESS_VOID(rv);
+
+    rv = (mCallback->*aCall)(data, jsapi.cx());
+    NS_ENSURE_SUCCESS_VOID(rv);
+  }
+
+ public:
+  using Base::AttachNative;
+
+  template <typename Functor>
+  static void OnNativeCall(Functor&& aCall) {
+    if (NS_IsMainThread()) {
+      // Invoke callbacks synchronously if we're already on Gecko thread.
+      return aCall();
+    }
+    NS_DispatchToMainThread(
+        NS_NewRunnableFunction("OnNativeCall", std::move(aCall)));
+  }
+
+  static void Finalize(const CallbackDelegate::LocalRef& aInstance) {
+    DisposeNative(aInstance);
+  }
+
+  NativeCallbackDelegateSupport(nsIAndroidEventCallback* callback,
+                                nsIAndroidEventFinalizer* finalizer,
+                                nsIGlobalObject* globalObject)
+      : mCallback(callback),
+        mFinalizer(finalizer),
+        mGlobalObject(globalObject) {}
+
+  ~NativeCallbackDelegateSupport() {
+    if (mFinalizer) {
+      mFinalizer->OnFinalize();
+    }
+  }
+
+  void SendSuccess(jni::Object::Param aData) {
+    Call(aData, &nsIAndroidEventCallback::OnSuccess);
+  }
+
+  void SendError(jni::Object::Param aData) {
+    Call(aData, &nsIAndroidEventCallback::OnError);
+  }
+};
+
+class FinalizingCallbackDelegate final : public nsIAndroidEventCallback {
+  const nsCOMPtr<nsIAndroidEventCallback> mCallback;
+  const nsCOMPtr<nsIAndroidEventFinalizer> mFinalizer;
+
+  virtual ~FinalizingCallbackDelegate() {
+    if (mFinalizer) {
+      mFinalizer->OnFinalize();
+    }
+  }
+
+ public:
+  FinalizingCallbackDelegate(nsIAndroidEventCallback* aCallback,
+                             nsIAndroidEventFinalizer* aFinalizer)
+      : mCallback(aCallback), mFinalizer(aFinalizer) {}
+
+  NS_DECL_ISUPPORTS
+  NS_FORWARD_NSIANDROIDEVENTCALLBACK(mCallback->);
+};
+
+NS_IMPL_ISUPPORTS(FinalizingCallbackDelegate, nsIAndroidEventCallback)
+
+}  // namespace detail
+
+using namespace detail;
+
+NS_IMPL_ISUPPORTS(EventDispatcher, nsIAndroidEventDispatcher)
+
+nsIGlobalObject* EventDispatcher::GetGlobalObject() {
+  if (mDOMWindow) {
+    return nsGlobalWindowInner::Cast(mDOMWindow->GetCurrentInnerWindow());
+  }
+  return xpc::NativeGlobal(xpc::PrivilegedJunkScope());
+}
+
+nsresult EventDispatcher::DispatchOnGecko(ListenersList* list,
+                                          const nsAString& aEvent,
+                                          JS::Handle<JS::Value> aData,
+                                          nsIAndroidEventCallback* aCallback) {
+  MOZ_ASSERT(NS_IsMainThread());
+  dom::AutoNoJSAPI nojsapi;
+
+  list->lockCount++;
+
+  auto iteratingScope = MakeScopeExit([list] {
+    list->lockCount--;
+    if (list->lockCount || !list->unregistering) {
+      return;
+    }
+
+    list->unregistering = false;
+    for (ssize_t i = list->listeners.Count() - 1; i >= 0; i--) {
+      if (list->listeners[i]) {
+        continue;
+      }
+      list->listeners.RemoveObjectAt(i);
+    }
+  });
+
+  const size_t count = list->listeners.Count();
+  for (size_t i = 0; i < count; i++) {
+    if (!list->listeners[i]) {
+      // Unregistered.
+      continue;
+    }
+    const nsresult rv = list->listeners[i]->OnEvent(aEvent, aData, aCallback);
+    Unused << NS_WARN_IF(NS_FAILED(rv));
+  }
+  return NS_OK;
+}
+
+java::EventDispatcher::NativeCallbackDelegate::LocalRef
+EventDispatcher::WrapCallback(nsIAndroidEventCallback* aCallback,
+                              nsIAndroidEventFinalizer* aFinalizer) {
+  if (!aCallback) {
+    return java::EventDispatcher::NativeCallbackDelegate::LocalRef(
+        jni::GetGeckoThreadEnv());
+  }
+
+  java::EventDispatcher::NativeCallbackDelegate::LocalRef callback =
+      java::EventDispatcher::NativeCallbackDelegate::New();
+  NativeCallbackDelegateSupport::AttachNative(
+      callback, MakeUnique<NativeCallbackDelegateSupport>(aCallback, aFinalizer,
+                                                          GetGlobalObject()));
+  return callback;
+}
+
+bool EventDispatcher::HasListener(const char16_t* aEvent) {
+  java::EventDispatcher::LocalRef dispatcher(mDispatcher);
+  if (!dispatcher) {
+    return false;
+  }
+
+  nsDependentString event(aEvent);
+  return dispatcher->HasListener(event);
+}
+
+NS_IMETHODIMP
+EventDispatcher::Dispatch(JS::Handle<JS::Value> aEvent,
+                          JS::Handle<JS::Value> aData,
+                          nsIAndroidEventCallback* aCallback,
+                          nsIAndroidEventFinalizer* aFinalizer,
+                          JSContext* aCx) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (!aEvent.isString()) {
+    NS_WARNING("Invalid event name");
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsAutoJSString event;
+  NS_ENSURE_TRUE(CheckJS(aCx, event.init(aCx, aEvent.toString())),
+                 NS_ERROR_OUT_OF_MEMORY);
+
+  // Don't need to lock here because we're on the main thread, and we can't
+  // race against Register/UnregisterListener.
+
+  ListenersList* list = mListenersMap.Get(event);
+  if (list) {
+    if (!aCallback || !aFinalizer) {
+      return DispatchOnGecko(list, event, aData, aCallback);
+    }
+    nsCOMPtr<nsIAndroidEventCallback> callback(
+        new FinalizingCallbackDelegate(aCallback, aFinalizer));
+    return DispatchOnGecko(list, event, aData, callback);
+  }
+
+  java::EventDispatcher::LocalRef dispatcher(mDispatcher);
+  if (!dispatcher) {
+    return NS_OK;
+  }
+
+  jni::Object::LocalRef data(jni::GetGeckoThreadEnv());
+  nsresult rv = BoxData(event, aCx, aData, data, /* ObjectOnly */ true);
+  // Keep XPConnect from overriding the JSContext exception with one
+  // based on the nsresult.
+  //
+  // XXXbz Does xpconnect still do that?  Needs to be checked/tested.
+  NS_ENSURE_SUCCESS(rv, JS_IsExceptionPending(aCx) ? NS_OK : rv);
+
+  dom::AutoNoJSAPI nojsapi;
+  dispatcher->DispatchToThreads(event, data,
+                                WrapCallback(aCallback, aFinalizer));
+  return NS_OK;
+}
+
+nsresult EventDispatcher::Dispatch(const char16_t* aEvent,
+                                   java::GeckoBundle::Param aData,
+                                   nsIAndroidEventCallback* aCallback) {
+  nsDependentString event(aEvent);
+
+  ListenersList* list = mListenersMap.Get(event);
+  if (list) {
+    dom::AutoJSAPI jsapi;
+    NS_ENSURE_TRUE(jsapi.Init(GetGlobalObject()), NS_ERROR_FAILURE);
+    JS::Rooted<JS::Value> data(jsapi.cx());
+    nsresult rv = UnboxData(/* Event */ nullptr, jsapi.cx(), aData, &data,
+                            /* BundleOnly */ true);
+    NS_ENSURE_SUCCESS(rv, rv);
+    return DispatchOnGecko(list, event, data, aCallback);
+  }
+
+  java::EventDispatcher::LocalRef dispatcher(mDispatcher);
+  if (!dispatcher) {
+    return NS_OK;
+  }
+
+  dispatcher->DispatchToThreads(event, aData, WrapCallback(aCallback));
+  return NS_OK;
+}
+
+nsresult EventDispatcher::IterateEvents(JSContext* aCx,
+                                        JS::Handle<JS::Value> aEvents,
+                                        IterateEventsCallback aCallback,
+                                        nsIAndroidEventListener* aListener) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  MutexAutoLock lock(mLock);
+
+  auto processEvent = [this, aCx, aCallback,
+                       aListener](JS::Handle<JS::Value> event) -> nsresult {
+    nsAutoJSString str;
+    NS_ENSURE_TRUE(CheckJS(aCx, str.init(aCx, event.toString())),
+                   NS_ERROR_OUT_OF_MEMORY);
+    return (this->*aCallback)(str, aListener);
+  };
+
+  if (aEvents.isString()) {
+    return processEvent(aEvents);
+  }
+
+  bool isArray = false;
+  NS_ENSURE_TRUE(aEvents.isObject(), NS_ERROR_INVALID_ARG);
+  NS_ENSURE_TRUE(CheckJS(aCx, JS::IsArrayObject(aCx, aEvents, &isArray)),
+                 NS_ERROR_INVALID_ARG);
+  NS_ENSURE_TRUE(isArray, NS_ERROR_INVALID_ARG);
+
+  JS::Rooted<JSObject*> events(aCx, &aEvents.toObject());
+  uint32_t length = 0;
+  NS_ENSURE_TRUE(CheckJS(aCx, JS::GetArrayLength(aCx, events, &length)),
+                 NS_ERROR_INVALID_ARG);
+  NS_ENSURE_TRUE(length, NS_ERROR_INVALID_ARG);
+
+  for (size_t i = 0; i < length; i++) {
+    JS::Rooted<JS::Value> event(aCx);
+    NS_ENSURE_TRUE(CheckJS(aCx, JS_GetElement(aCx, events, i, &event)),
+                   NS_ERROR_INVALID_ARG);
+    NS_ENSURE_TRUE(event.isString(), NS_ERROR_INVALID_ARG);
+
+    const nsresult rv = processEvent(event);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+  return NS_OK;
+}
+
+nsresult EventDispatcher::RegisterEventLocked(
+    const nsAString& aEvent, nsIAndroidEventListener* aListener) {
+  ListenersList* list = mListenersMap.GetOrInsertNew(aEvent);
+
+#ifdef DEBUG
+  for (ssize_t i = 0; i < list->listeners.Count(); i++) {
+    NS_ENSURE_TRUE(list->listeners[i] != aListener,
+                   NS_ERROR_ALREADY_INITIALIZED);
+  }
+#endif
+
+  list->listeners.AppendObject(aListener);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+EventDispatcher::RegisterListener(nsIAndroidEventListener* aListener,
+                                  JS::Handle<JS::Value> aEvents,
+                                  JSContext* aCx) {
+  return IterateEvents(aCx, aEvents, &EventDispatcher::RegisterEventLocked,
+                       aListener);
+}
+
+nsresult EventDispatcher::UnregisterEventLocked(
+    const nsAString& aEvent, nsIAndroidEventListener* aListener) {
+  ListenersList* list = mListenersMap.Get(aEvent);
+#ifdef DEBUG
+  NS_ENSURE_TRUE(list, NS_ERROR_NOT_INITIALIZED);
+#else
+  NS_ENSURE_TRUE(list, NS_OK);
+#endif
+
+  DebugOnly<bool> found = false;
+  for (ssize_t i = list->listeners.Count() - 1; i >= 0; i--) {
+    if (list->listeners[i] != aListener) {
+      continue;
+    }
+    if (list->lockCount) {
+      // Only mark for removal when list is locked.
+      list->listeners.ReplaceObjectAt(nullptr, i);
+      list->unregistering = true;
+    } else {
+      list->listeners.RemoveObjectAt(i);
+    }
+    found = true;
+  }
+#ifdef DEBUG
+  return found ? NS_OK : NS_ERROR_NOT_INITIALIZED;
+#else
+  return NS_OK;
+#endif
+}
+
+NS_IMETHODIMP
+EventDispatcher::UnregisterListener(nsIAndroidEventListener* aListener,
+                                    JS::Handle<JS::Value> aEvents,
+                                    JSContext* aCx) {
+  return IterateEvents(aCx, aEvents, &EventDispatcher::UnregisterEventLocked,
+                       aListener);
+}
+
+void EventDispatcher::Attach(java::EventDispatcher::Param aDispatcher,
+                             nsPIDOMWindowOuter* aDOMWindow) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aDispatcher);
+
+  java::EventDispatcher::LocalRef dispatcher(mDispatcher);
+
+  if (dispatcher) {
+    if (dispatcher == aDispatcher) {
+      // Only need to update the window.
+      mDOMWindow = aDOMWindow;
+      return;
+    }
+    dispatcher->SetAttachedToGecko(java::EventDispatcher::REATTACHING);
+  }
+
+  dispatcher = java::EventDispatcher::LocalRef(aDispatcher);
+  NativesBase::AttachNative(dispatcher, this);
+  mDispatcher = dispatcher;
+  mDOMWindow = aDOMWindow;
+
+  dispatcher->SetAttachedToGecko(java::EventDispatcher::ATTACHED);
+}
+
+void EventDispatcher::Shutdown() {
+  mDispatcher = nullptr;
+  mDOMWindow = nullptr;
+}
+
+void EventDispatcher::Detach() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mDispatcher);
+
+  java::EventDispatcher::GlobalRef dispatcher(mDispatcher);
+
+  // SetAttachedToGecko will call disposeNative for us later on the Gecko
+  // thread to make sure all pending dispatchToGecko calls have completed.
+  if (dispatcher) {
+    dispatcher->SetAttachedToGecko(java::EventDispatcher::DETACHED);
+  }
+
+  Shutdown();
+}
+
+bool EventDispatcher::HasGeckoListener(jni::String::Param aEvent) {
+  // Can be called from any thread.
+  MutexAutoLock lock(mLock);
+  return !!mListenersMap.Get(aEvent->ToString());
+}
+
+void EventDispatcher::DispatchToGecko(jni::String::Param aEvent,
+                                      jni::Object::Param aData,
+                                      jni::Object::Param aCallback) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // Don't need to lock here because we're on the main thread, and we can't
+  // race against Register/UnregisterListener.
+
+  nsString event = aEvent->ToString();
+  ListenersList* list = mListenersMap.Get(event);
+  if (!list || list->listeners.IsEmpty()) {
+    return;
+  }
+
+  // Use the same compartment as the attached window if possible, otherwise
+  // use a default compartment.
+  dom::AutoJSAPI jsapi;
+  NS_ENSURE_TRUE_VOID(jsapi.Init(GetGlobalObject()));
+
+  JS::Rooted<JS::Value> data(jsapi.cx());
+  nsresult rv = UnboxData(aEvent, jsapi.cx(), aData, &data,
+                          /* BundleOnly */ true);
+  NS_ENSURE_SUCCESS_VOID(rv);
+
+  nsCOMPtr<nsIAndroidEventCallback> callback;
+  if (aCallback) {
+    callback =
+        new JavaCallbackDelegate(java::EventCallback::Ref::From(aCallback));
+  }
+
+  DispatchOnGecko(list, event, data, callback);
+}
+
+/* static */
+nsresult EventDispatcher::UnboxBundle(JSContext* aCx, jni::Object::Param aData,
+                                      JS::MutableHandle<JS::Value> aOut) {
+  return detail::UnboxBundle(aCx, aData, aOut);
+}
+
+}  // namespace widget
+}  // namespace mozilla
+
+#if defined(__clang__)
+#  pragma clang diagnostic pop
+#endif
diff --git a/widget/android/EventDispatcher.h b/widget/android/EventDispatcher.h
new file mode 100644
index 0000000000..a7daa18d7d
--- /dev/null
+++ b/widget/android/EventDispatcher.h
@@ -0,0 +1,104 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * vim: set sw=2 ts=4 expandtab:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_EventDispatcher_h
+#define mozilla_widget_EventDispatcher_h
+
+#include "jsapi.h"
+#include "nsClassHashtable.h"
+#include "nsCOMArray.h"
+#include "nsIAndroidBridge.h"
+#include "nsHashKeys.h"
+#include "nsPIDOMWindow.h"
+
+#include "mozilla/java/EventDispatcherNatives.h"
+#include "mozilla/java/GeckoBundleWrappers.h"
+#include "mozilla/Mutex.h"
+
+namespace mozilla {
+namespace widget {
+
+/**
+ * EventDispatcher is the Gecko counterpart to the Java EventDispatcher class.
+ * Together, they make up a unified event bus. Events dispatched from the Java
+ * side may notify event listeners on the Gecko side, and vice versa.
+ */
+class EventDispatcher final
+    : public nsIAndroidEventDispatcher,
+      public java::EventDispatcher::Natives<EventDispatcher> {
+  using NativesBase = java::EventDispatcher::Natives<EventDispatcher>;
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIANDROIDEVENTDISPATCHER
+
+  EventDispatcher() {}
+
+  void Attach(java::EventDispatcher::Param aDispatcher,
+              nsPIDOMWindowOuter* aDOMWindow);
+  void Detach();
+
+  nsresult Dispatch(const char16_t* aEvent,
+                    java::GeckoBundle::Param aData = nullptr,
+                    nsIAndroidEventCallback* aCallback = nullptr);
+
+  bool HasListener(const char16_t* aEvent);
+  bool HasGeckoListener(jni::String::Param aEvent);
+  void DispatchToGecko(jni::String::Param aEvent, jni::Object::Param aData,
+                       jni::Object::Param aCallback);
+
+  static nsresult UnboxBundle(JSContext* aCx, jni::Object::Param aData,
+                              JS::MutableHandle<JS::Value> aOut);
+
+  nsIGlobalObject* GetGlobalObject();
+
+  using NativesBase::DisposeNative;
+
+ private:
+  friend class java::EventDispatcher::Natives<EventDispatcher>;
+
+  java::EventDispatcher::WeakRef mDispatcher;
+  nsCOMPtr<nsPIDOMWindowOuter> mDOMWindow;
+
+  virtual ~EventDispatcher() {}
+
+  void Shutdown();
+
+  struct ListenersList {
+    nsCOMArray<nsIAndroidEventListener> listeners{/* count */ 1};
+    // 0 if the list can be modified
+    uint32_t lockCount{0};
+    // true if this list has a listener that is being unregistered
+    bool unregistering{false};
+  };
+
+  using ListenersMap = nsClassHashtable<nsStringHashKey, ListenersList>;
+
+  Mutex mLock MOZ_UNANNOTATED{"mozilla::widget::EventDispatcher"};
+  ListenersMap mListenersMap;
+
+  using IterateEventsCallback =
+      nsresult (EventDispatcher::*)(const nsAString&, nsIAndroidEventListener*);
+
+  nsresult IterateEvents(JSContext* aCx, JS::Handle<JS::Value> aEvents,
+                         IterateEventsCallback aCallback,
+                         nsIAndroidEventListener* aListener);
+  nsresult RegisterEventLocked(const nsAString&, nsIAndroidEventListener*);
+  nsresult UnregisterEventLocked(const nsAString&, nsIAndroidEventListener*);
+
+  nsresult DispatchOnGecko(ListenersList* list, const nsAString& aEvent,
+                           JS::Handle<JS::Value> aData,
+                           nsIAndroidEventCallback* aCallback);
+
+  java::EventDispatcher::NativeCallbackDelegate::LocalRef WrapCallback(
+      nsIAndroidEventCallback* aCallback,
+      nsIAndroidEventFinalizer* aFinalizer = nullptr);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_EventDispatcher_h
diff --git a/widget/android/GeckoBatteryManager.h b/widget/android/GeckoBatteryManager.h
new file mode 100644
index 0000000000..d9a171d0d1
--- /dev/null
+++ b/widget/android/GeckoBatteryManager.h
@@ -0,0 +1,28 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GeckoBatteryManager_h
+#define GeckoBatteryManager_h
+
+#include "nsAppShell.h"
+
+#include "mozilla/Hal.h"
+#include "mozilla/java/GeckoBatteryManagerNatives.h"
+
+namespace mozilla {
+
+class GeckoBatteryManager final
+    : public java::GeckoBatteryManager::Natives<GeckoBatteryManager> {
+ public:
+  static void OnBatteryChange(double aLevel, bool aCharging,
+                              double aRemainingTime) {
+    hal::NotifyBatteryChange(
+        hal::BatteryInformation(aLevel, aCharging, aRemainingTime));
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // GeckoBatteryManager_h
diff --git a/widget/android/GeckoEditableSupport.cpp b/widget/android/GeckoEditableSupport.cpp
new file mode 100644
index 0000000000..fcac5d5399
--- /dev/null
+++ b/widget/android/GeckoEditableSupport.cpp
@@ -0,0 +1,1684 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 4; indent-tabs-mode: nil; -*-
+ * vim: set sw=2 ts=4 expandtab:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GeckoEditableSupport.h"
+
+#include "AndroidRect.h"
+#include "KeyEvent.h"
+#include "PuppetWidget.h"
+#include "nsIContent.h"
+#include "nsITransferable.h"
+#include "nsStringStream.h"
+
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/IMEStateManager.h"
+#include "mozilla/java/GeckoEditableChildWrappers.h"
+#include "mozilla/java/GeckoServiceChildProcessWrappers.h"
+#include "mozilla/jni/NativesInlines.h"
+#include "mozilla/Logging.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_intl.h"
+#include "mozilla/TextComposition.h"
+#include "mozilla/TextEventDispatcherListener.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/ToString.h"
+#include "mozilla/dom/BrowserChild.h"
+#include "mozilla/widget/GeckoViewSupport.h"
+
+#include <android/api-level.h>
+#include <android/input.h>
+#include <android/log.h>
+
+#ifdef NIGHTLY_BUILD
+static mozilla::LazyLogModule sGeckoEditableSupportLog("GeckoEditableSupport");
+#  define ALOGIME(...) \
+    MOZ_LOG(sGeckoEditableSupportLog, LogLevel::Debug, (__VA_ARGS__))
+#else
+#  define ALOGIME(args...) \
+    do {                   \
+    } while (0)
+#endif
+
+static uint32_t ConvertAndroidKeyCodeToDOMKeyCode(int32_t androidKeyCode) {
+  // Special-case alphanumeric keycodes because they are most common.
+  if (androidKeyCode >= AKEYCODE_A && androidKeyCode <= AKEYCODE_Z) {
+    return androidKeyCode - AKEYCODE_A + NS_VK_A;
+  }
+
+  if (androidKeyCode >= AKEYCODE_0 && androidKeyCode <= AKEYCODE_9) {
+    return androidKeyCode - AKEYCODE_0 + NS_VK_0;
+  }
+
+  switch (androidKeyCode) {
+    // KEYCODE_UNKNOWN (0) ... KEYCODE_HOME (3)
+    case AKEYCODE_BACK:
+      return NS_VK_ESCAPE;
+    // KEYCODE_CALL (5) ... KEYCODE_POUND (18)
+    case AKEYCODE_DPAD_UP:
+      return NS_VK_UP;
+    case AKEYCODE_DPAD_DOWN:
+      return NS_VK_DOWN;
+    case AKEYCODE_DPAD_LEFT:
+      return NS_VK_LEFT;
+    case AKEYCODE_DPAD_RIGHT:
+      return NS_VK_RIGHT;
+    case AKEYCODE_DPAD_CENTER:
+      return NS_VK_RETURN;
+    case AKEYCODE_VOLUME_UP:
+      return NS_VK_VOLUME_UP;
+    case AKEYCODE_VOLUME_DOWN:
+      return NS_VK_VOLUME_DOWN;
+    // KEYCODE_VOLUME_POWER (26) ... KEYCODE_Z (54)
+    case AKEYCODE_COMMA:
+      return NS_VK_COMMA;
+    case AKEYCODE_PERIOD:
+      return NS_VK_PERIOD;
+    case AKEYCODE_ALT_LEFT:
+      return NS_VK_ALT;
+    case AKEYCODE_ALT_RIGHT:
+      return NS_VK_ALT;
+    case AKEYCODE_SHIFT_LEFT:
+      return NS_VK_SHIFT;
+    case AKEYCODE_SHIFT_RIGHT:
+      return NS_VK_SHIFT;
+    case AKEYCODE_TAB:
+      return NS_VK_TAB;
+    case AKEYCODE_SPACE:
+      return NS_VK_SPACE;
+    // KEYCODE_SYM (63) ... KEYCODE_ENVELOPE (65)
+    case AKEYCODE_ENTER:
+      return NS_VK_RETURN;
+    case AKEYCODE_DEL:
+      return NS_VK_BACK;  // Backspace
+    case AKEYCODE_GRAVE:
+      return NS_VK_BACK_QUOTE;
+    // KEYCODE_MINUS (69)
+    case AKEYCODE_EQUALS:
+      return NS_VK_EQUALS;
+    case AKEYCODE_LEFT_BRACKET:
+      return NS_VK_OPEN_BRACKET;
+    case AKEYCODE_RIGHT_BRACKET:
+      return NS_VK_CLOSE_BRACKET;
+    case AKEYCODE_BACKSLASH:
+      return NS_VK_BACK_SLASH;
+    case AKEYCODE_SEMICOLON:
+      return NS_VK_SEMICOLON;
+    // KEYCODE_APOSTROPHE (75)
+    case AKEYCODE_SLASH:
+      return NS_VK_SLASH;
+    // KEYCODE_AT (77) ... KEYCODE_MEDIA_FAST_FORWARD (90)
+    case AKEYCODE_MUTE:
+      return NS_VK_VOLUME_MUTE;
+    case AKEYCODE_PAGE_UP:
+      return NS_VK_PAGE_UP;
+    case AKEYCODE_PAGE_DOWN:
+      return NS_VK_PAGE_DOWN;
+    // KEYCODE_PICTSYMBOLS (94) ... KEYCODE_BUTTON_MODE (110)
+    case AKEYCODE_ESCAPE:
+      return NS_VK_ESCAPE;
+    case AKEYCODE_FORWARD_DEL:
+      return NS_VK_DELETE;
+    case AKEYCODE_CTRL_LEFT:
+      return NS_VK_CONTROL;
+    case AKEYCODE_CTRL_RIGHT:
+      return NS_VK_CONTROL;
+    case AKEYCODE_CAPS_LOCK:
+      return NS_VK_CAPS_LOCK;
+    case AKEYCODE_SCROLL_LOCK:
+      return NS_VK_SCROLL_LOCK;
+    // KEYCODE_META_LEFT (117) ... KEYCODE_FUNCTION (119)
+    case AKEYCODE_SYSRQ:
+      return NS_VK_PRINTSCREEN;
+    case AKEYCODE_BREAK:
+      return NS_VK_PAUSE;
+    case AKEYCODE_MOVE_HOME:
+      return NS_VK_HOME;
+    case AKEYCODE_MOVE_END:
+      return NS_VK_END;
+    case AKEYCODE_INSERT:
+      return NS_VK_INSERT;
+    // KEYCODE_FORWARD (125) ... KEYCODE_MEDIA_RECORD (130)
+    case AKEYCODE_F1:
+      return NS_VK_F1;
+    case AKEYCODE_F2:
+      return NS_VK_F2;
+    case AKEYCODE_F3:
+      return NS_VK_F3;
+    case AKEYCODE_F4:
+      return NS_VK_F4;
+    case AKEYCODE_F5:
+      return NS_VK_F5;
+    case AKEYCODE_F6:
+      return NS_VK_F6;
+    case AKEYCODE_F7:
+      return NS_VK_F7;
+    case AKEYCODE_F8:
+      return NS_VK_F8;
+    case AKEYCODE_F9:
+      return NS_VK_F9;
+    case AKEYCODE_F10:
+      return NS_VK_F10;
+    case AKEYCODE_F11:
+      return NS_VK_F11;
+    case AKEYCODE_F12:
+      return NS_VK_F12;
+    case AKEYCODE_NUM_LOCK:
+      return NS_VK_NUM_LOCK;
+    case AKEYCODE_NUMPAD_0:
+      return NS_VK_NUMPAD0;
+    case AKEYCODE_NUMPAD_1:
+      return NS_VK_NUMPAD1;
+    case AKEYCODE_NUMPAD_2:
+      return NS_VK_NUMPAD2;
+    case AKEYCODE_NUMPAD_3:
+      return NS_VK_NUMPAD3;
+    case AKEYCODE_NUMPAD_4:
+      return NS_VK_NUMPAD4;
+    case AKEYCODE_NUMPAD_5:
+      return NS_VK_NUMPAD5;
+    case AKEYCODE_NUMPAD_6:
+      return NS_VK_NUMPAD6;
+    case AKEYCODE_NUMPAD_7:
+      return NS_VK_NUMPAD7;
+    case AKEYCODE_NUMPAD_8:
+      return NS_VK_NUMPAD8;
+    case AKEYCODE_NUMPAD_9:
+      return NS_VK_NUMPAD9;
+    case AKEYCODE_NUMPAD_DIVIDE:
+      return NS_VK_DIVIDE;
+    case AKEYCODE_NUMPAD_MULTIPLY:
+      return NS_VK_MULTIPLY;
+    case AKEYCODE_NUMPAD_SUBTRACT:
+      return NS_VK_SUBTRACT;
+    case AKEYCODE_NUMPAD_ADD:
+      return NS_VK_ADD;
+    case AKEYCODE_NUMPAD_DOT:
+      return NS_VK_DECIMAL;
+    case AKEYCODE_NUMPAD_COMMA:
+      return NS_VK_SEPARATOR;
+    case AKEYCODE_NUMPAD_ENTER:
+      return NS_VK_RETURN;
+    case AKEYCODE_NUMPAD_EQUALS:
+      return NS_VK_EQUALS;
+    // KEYCODE_NUMPAD_LEFT_PAREN (162) ... KEYCODE_CALCULATOR (210)
+
+    // Needs to confirm the behavior.  If the key switches the open state
+    // of Japanese IME (or switches input character between Hiragana and
+    // Roman numeric characters), then, it might be better to use
+    // NS_VK_KANJI which is used for Alt+Zenkaku/Hankaku key on Windows.
+    case AKEYCODE_ZENKAKU_HANKAKU:
+      return 0;
+    case AKEYCODE_EISU:
+      return NS_VK_EISU;
+    case AKEYCODE_MUHENKAN:
+      return NS_VK_NONCONVERT;
+    case AKEYCODE_HENKAN:
+      return NS_VK_CONVERT;
+    case AKEYCODE_KATAKANA_HIRAGANA:
+      return 0;
+    case AKEYCODE_YEN:
+      return NS_VK_BACK_SLASH;  // Same as other platforms.
+    case AKEYCODE_RO:
+      return NS_VK_BACK_SLASH;  // Same as other platforms.
+    case AKEYCODE_KANA:
+      return NS_VK_KANA;
+    case AKEYCODE_ASSIST:
+      return NS_VK_HELP;
+
+    // the A key is the action key for gamepad devices.
+    case AKEYCODE_BUTTON_A:
+      return NS_VK_RETURN;
+
+    default:
+      ALOG(
+          "ConvertAndroidKeyCodeToDOMKeyCode: "
+          "No DOM keycode for Android keycode %d",
+          int(androidKeyCode));
+      return 0;
+  }
+}
+
+static KeyNameIndex ConvertAndroidKeyCodeToKeyNameIndex(
+    int32_t keyCode, int32_t action, int32_t domPrintableKeyValue) {
+  // Special-case alphanumeric keycodes because they are most common.
+  if (keyCode >= AKEYCODE_A && keyCode <= AKEYCODE_Z) {
+    return KEY_NAME_INDEX_USE_STRING;
+  }
+
+  if (keyCode >= AKEYCODE_0 && keyCode <= AKEYCODE_9) {
+    return KEY_NAME_INDEX_USE_STRING;
+  }
+
+  switch (keyCode) {
+#define NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, aKeyNameIndex) \
+  case aNativeKey:                                                     \
+    return aKeyNameIndex;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+
+    // KEYCODE_0 (7) ... KEYCODE_9 (16)
+    case AKEYCODE_STAR:   // '*' key
+    case AKEYCODE_POUND:  // '#' key
+
+      // KEYCODE_A (29) ... KEYCODE_Z (54)
+
+    case AKEYCODE_COMMA:   // ',' key
+    case AKEYCODE_PERIOD:  // '.' key
+    case AKEYCODE_SPACE:
+    case AKEYCODE_GRAVE:          // '`' key
+    case AKEYCODE_MINUS:          // '-' key
+    case AKEYCODE_EQUALS:         // '=' key
+    case AKEYCODE_LEFT_BRACKET:   // '[' key
+    case AKEYCODE_RIGHT_BRACKET:  // ']' key
+    case AKEYCODE_BACKSLASH:      // '\' key
+    case AKEYCODE_SEMICOLON:      // ';' key
+    case AKEYCODE_APOSTROPHE:     // ''' key
+    case AKEYCODE_SLASH:          // '/' key
+    case AKEYCODE_AT:             // '@' key
+    case AKEYCODE_PLUS:           // '+' key
+
+    case AKEYCODE_NUMPAD_0:
+    case AKEYCODE_NUMPAD_1:
+    case AKEYCODE_NUMPAD_2:
+    case AKEYCODE_NUMPAD_3:
+    case AKEYCODE_NUMPAD_4:
+    case AKEYCODE_NUMPAD_5:
+    case AKEYCODE_NUMPAD_6:
+    case AKEYCODE_NUMPAD_7:
+    case AKEYCODE_NUMPAD_8:
+    case AKEYCODE_NUMPAD_9:
+    case AKEYCODE_NUMPAD_DIVIDE:
+    case AKEYCODE_NUMPAD_MULTIPLY:
+    case AKEYCODE_NUMPAD_SUBTRACT:
+    case AKEYCODE_NUMPAD_ADD:
+    case AKEYCODE_NUMPAD_DOT:
+    case AKEYCODE_NUMPAD_COMMA:
+    case AKEYCODE_NUMPAD_EQUALS:
+    case AKEYCODE_NUMPAD_LEFT_PAREN:
+    case AKEYCODE_NUMPAD_RIGHT_PAREN:
+
+    case AKEYCODE_YEN:  // yen sign key
+    case AKEYCODE_RO:   // Japanese Ro key
+      return KEY_NAME_INDEX_USE_STRING;
+
+    case AKEYCODE_NUM:  // XXX Not sure
+    case AKEYCODE_PICTSYMBOLS:
+
+    case AKEYCODE_BUTTON_A:
+    case AKEYCODE_BUTTON_B:
+    case AKEYCODE_BUTTON_C:
+    case AKEYCODE_BUTTON_X:
+    case AKEYCODE_BUTTON_Y:
+    case AKEYCODE_BUTTON_Z:
+    case AKEYCODE_BUTTON_L1:
+    case AKEYCODE_BUTTON_R1:
+    case AKEYCODE_BUTTON_L2:
+    case AKEYCODE_BUTTON_R2:
+    case AKEYCODE_BUTTON_THUMBL:
+    case AKEYCODE_BUTTON_THUMBR:
+    case AKEYCODE_BUTTON_START:
+    case AKEYCODE_BUTTON_SELECT:
+    case AKEYCODE_BUTTON_MODE:
+
+    case AKEYCODE_MEDIA_CLOSE:
+
+    case AKEYCODE_BUTTON_1:
+    case AKEYCODE_BUTTON_2:
+    case AKEYCODE_BUTTON_3:
+    case AKEYCODE_BUTTON_4:
+    case AKEYCODE_BUTTON_5:
+    case AKEYCODE_BUTTON_6:
+    case AKEYCODE_BUTTON_7:
+    case AKEYCODE_BUTTON_8:
+    case AKEYCODE_BUTTON_9:
+    case AKEYCODE_BUTTON_10:
+    case AKEYCODE_BUTTON_11:
+    case AKEYCODE_BUTTON_12:
+    case AKEYCODE_BUTTON_13:
+    case AKEYCODE_BUTTON_14:
+    case AKEYCODE_BUTTON_15:
+    case AKEYCODE_BUTTON_16:
+      return KEY_NAME_INDEX_Unidentified;
+
+    case AKEYCODE_UNKNOWN:
+      MOZ_ASSERT(action != AKEY_EVENT_ACTION_MULTIPLE,
+                 "Don't call this when action is AKEY_EVENT_ACTION_MULTIPLE!");
+      // It's actually an unknown key if the action isn't ACTION_MULTIPLE.
+      // However, it might cause text input.  So, let's check the value.
+      return domPrintableKeyValue ? KEY_NAME_INDEX_USE_STRING
+                                  : KEY_NAME_INDEX_Unidentified;
+
+    default:
+      ALOG(
+          "ConvertAndroidKeyCodeToKeyNameIndex: "
+          "No DOM key name index for Android keycode %d",
+          keyCode);
+      return KEY_NAME_INDEX_Unidentified;
+  }
+}
+
+static CodeNameIndex ConvertAndroidScanCodeToCodeNameIndex(int32_t scanCode) {
+  switch (scanCode) {
+#define NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX(aNativeKey, aCodeNameIndex) \
+  case aNativeKey:                                                       \
+    return aCodeNameIndex;
+
+#include "NativeKeyToDOMCodeName.h"
+
+#undef NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX
+
+    default:
+      return CODE_NAME_INDEX_UNKNOWN;
+  }
+}
+
+static void InitKeyEvent(WidgetKeyboardEvent& aEvent, int32_t aAction,
+                         int32_t aKeyCode, int32_t aScanCode,
+                         int32_t aMetaState, int64_t aTime,
+                         int32_t aDomPrintableKeyValue, int32_t aRepeatCount,
+                         int32_t aFlags) {
+  const uint32_t domKeyCode = ConvertAndroidKeyCodeToDOMKeyCode(aKeyCode);
+
+  aEvent.mModifiers = nsWindow::GetModifiers(aMetaState);
+  aEvent.mKeyCode = domKeyCode;
+
+  aEvent.mIsRepeat =
+      (aEvent.mMessage == eKeyDown || aEvent.mMessage == eKeyPress) &&
+      ((aFlags & java::sdk::KeyEvent::FLAG_LONG_PRESS) || aRepeatCount);
+
+  aEvent.mKeyNameIndex = ConvertAndroidKeyCodeToKeyNameIndex(
+      aKeyCode, aAction, aDomPrintableKeyValue);
+  aEvent.mCodeNameIndex = ConvertAndroidScanCodeToCodeNameIndex(aScanCode);
+
+  if (aEvent.mKeyNameIndex == KEY_NAME_INDEX_USE_STRING &&
+      aDomPrintableKeyValue) {
+    aEvent.mKeyValue = char16_t(aDomPrintableKeyValue);
+  }
+
+  aEvent.mLocation =
+      WidgetKeyboardEvent::ComputeLocationFromCodeValue(aEvent.mCodeNameIndex);
+  aEvent.mTimeStamp = nsWindow::GetEventTimeStamp(aTime);
+}
+
+static nscolor ConvertAndroidColor(uint32_t aArgb) {
+  return NS_RGBA((aArgb & 0x00ff0000) >> 16, (aArgb & 0x0000ff00) >> 8,
+                 (aArgb & 0x000000ff), (aArgb & 0xff000000) >> 24);
+}
+
+static jni::ObjectArray::LocalRef ConvertRectArrayToJavaRectFArray(
+    const nsTArray<LayoutDeviceIntRect>& aRects) {
+  const size_t length = aRects.Length();
+  auto rects = jni::ObjectArray::New<java::sdk::RectF>(length);
+
+  for (size_t i = 0; i < length; i++) {
+    const LayoutDeviceIntRect& tmp = aRects[i];
+
+    auto rect = java::sdk::RectF::New(tmp.x, tmp.y, tmp.XMost(), tmp.YMost());
+    rects->SetElement(i, rect);
+  }
+  return rects;
+}
+
+namespace mozilla {
+namespace widget {
+
+NS_IMPL_ISUPPORTS(GeckoEditableSupport, TextEventDispatcherListener,
+                  nsISupportsWeakReference)
+
+// This is the blocker helper class whether disposing GeckoEditableChild now.
+// During JNI call from GeckoEditableChild, we shouldn't dispose it.
+class MOZ_RAII AutoGeckoEditableBlocker final {
+ public:
+  explicit AutoGeckoEditableBlocker(GeckoEditableSupport* aGeckoEditableSupport)
+      : mGeckoEditable(aGeckoEditableSupport) {
+    mGeckoEditable->AddBlocker();
+  }
+  ~AutoGeckoEditableBlocker() { mGeckoEditable->ReleaseBlocker(); }
+
+ private:
+  RefPtr<GeckoEditableSupport> mGeckoEditable;
+};
+
+RefPtr<TextComposition> GeckoEditableSupport::GetComposition() const {
+  nsCOMPtr<nsIWidget> widget = GetWidget();
+  return widget ? IMEStateManager::GetTextCompositionFor(widget) : nullptr;
+}
+
+bool GeckoEditableSupport::RemoveComposition(RemoveCompositionFlag aFlag) {
+  if (!mDispatcher || !mDispatcher->IsComposing()) {
+    return false;
+  }
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+
+  NS_ENSURE_SUCCESS(BeginInputTransaction(mDispatcher), false);
+  mDispatcher->CommitComposition(
+      status, aFlag == CANCEL_IME_COMPOSITION ? &EmptyString() : nullptr);
+  return true;
+}
+
+void GeckoEditableSupport::OnKeyEvent(int32_t aAction, int32_t aKeyCode,
+                                      int32_t aScanCode, int32_t aMetaState,
+                                      int32_t aKeyPressMetaState, int64_t aTime,
+                                      int32_t aDomPrintableKeyValue,
+                                      int32_t aRepeatCount, int32_t aFlags,
+                                      bool aIsSynthesizedImeKey,
+                                      jni::Object::Param aOriginalEvent) {
+  AutoGeckoEditableBlocker blocker(this);
+
+  nsCOMPtr<nsIWidget> widget = GetWidget();
+  RefPtr<TextEventDispatcher> dispatcher =
+      mDispatcher ? mDispatcher.get()
+      : widget    ? widget->GetTextEventDispatcher()
+                  : nullptr;
+  NS_ENSURE_TRUE_VOID(dispatcher && widget);
+
+  if (!aIsSynthesizedImeKey) {
+    if (nsWindow* window = GetNsWindow()) {
+      window->UserActivity();
+    }
+  } else if (aIsSynthesizedImeKey && mIMEMaskEventsCount > 0) {
+    // Don't synthesize editor keys when not focused.
+    return;
+  }
+
+  EventMessage msg;
+  if (aAction == java::sdk::KeyEvent::ACTION_DOWN) {
+    msg = eKeyDown;
+  } else if (aAction == java::sdk::KeyEvent::ACTION_UP) {
+    msg = eKeyUp;
+  } else if (aAction == java::sdk::KeyEvent::ACTION_MULTIPLE) {
+    // Keys with multiple action are handled in Java,
+    // and we should never see one here
+    MOZ_CRASH("Cannot handle key with multiple action");
+  } else {
+    NS_WARNING("Unknown key action event");
+    return;
+  }
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  WidgetKeyboardEvent event(true, msg, widget);
+  InitKeyEvent(event, aAction, aKeyCode, aScanCode, aMetaState, aTime,
+               aDomPrintableKeyValue, aRepeatCount, aFlags);
+
+  if (nsIWidget::UsePuppetWidgets()) {
+    // Don't use native key bindings.
+    event.PreventNativeKeyBindings();
+  }
+
+  if (aIsSynthesizedImeKey) {
+    // Keys synthesized by Java IME code are saved in the mIMEKeyEvents
+    // array until the next IME_REPLACE_TEXT event, at which point
+    // these keys are dispatched in sequence.
+    mIMEKeyEvents.AppendElement(UniquePtr<WidgetEvent>(event.Duplicate()));
+  } else {
+    NS_ENSURE_SUCCESS_VOID(BeginInputTransaction(dispatcher));
+    dispatcher->DispatchKeyboardEvent(msg, event, status);
+    if (widget->Destroyed() || status == nsEventStatus_eConsumeNoDefault) {
+      // Skip default processing.
+      return;
+    }
+    mEditable->OnDefaultKeyEvent(aOriginalEvent);
+  }
+
+  // Only send keypress after keydown.
+  if (msg != eKeyDown) {
+    return;
+  }
+
+  WidgetKeyboardEvent pressEvent(true, eKeyPress, widget);
+  InitKeyEvent(pressEvent, aAction, aKeyCode, aScanCode, aKeyPressMetaState,
+               aTime, aDomPrintableKeyValue, aRepeatCount, aFlags);
+
+  if (nsIWidget::UsePuppetWidgets()) {
+    // Don't use native key bindings.
+    pressEvent.PreventNativeKeyBindings();
+  }
+
+  if (aIsSynthesizedImeKey) {
+    mIMEKeyEvents.AppendElement(UniquePtr<WidgetEvent>(pressEvent.Duplicate()));
+  } else {
+    dispatcher->MaybeDispatchKeypressEvents(pressEvent, status);
+  }
+}
+
+/*
+ * Send dummy key events for pages that are unaware of input events,
+ * to provide web compatibility for pages that depend on key events.
+ */
+void GeckoEditableSupport::SendIMEDummyKeyEvent(nsIWidget* aWidget,
+                                                EventMessage msg) {
+  AutoGeckoEditableBlocker blocker(this);
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  MOZ_ASSERT(mDispatcher);
+
+  WidgetKeyboardEvent event(true, msg, aWidget);
+  // TODO: If we can know scan code of the key event which caused replacing
+  //       composition string, we should set mCodeNameIndex here.  Then,
+  //       we should rename this method because it becomes not a "dummy"
+  //       keyboard event.
+  event.mKeyCode = NS_VK_PROCESSKEY;
+  event.mKeyNameIndex = KEY_NAME_INDEX_Process;
+  // KeyboardEvents marked as "processed by IME" shouldn't cause any edit
+  // actions.  So, we should set their native key binding to none before
+  // dispatch to avoid crash on PuppetWidget and avoid running redundant
+  // path to look for native key bindings.
+  if (nsIWidget::UsePuppetWidgets()) {
+    event.PreventNativeKeyBindings();
+  }
+  NS_ENSURE_SUCCESS_VOID(BeginInputTransaction(mDispatcher));
+  mDispatcher->DispatchKeyboardEvent(msg, event, status);
+}
+
+void GeckoEditableSupport::AddIMETextChange(
+    const IMENotification::TextChangeDataBase& aChange) {
+  mIMEPendingTextChange.MergeWith(aChange);
+
+  // We may not be in the middle of flushing,
+  // in which case this flag is meaningless.
+  mIMETextChangedDuringFlush = true;
+}
+
+void GeckoEditableSupport::PostFlushIMEChanges() {
+  if (mIMEPendingTextChange.IsValid() || mIMESelectionChanged) {
+    // Already posted
+    return;
+  }
+
+  RefPtr<GeckoEditableSupport> self(this);
+
+  nsAppShell::PostEvent([this, self] {
+    nsCOMPtr<nsIWidget> widget = GetWidget();
+    if (widget && !widget->Destroyed()) {
+      FlushIMEChanges();
+    }
+  });
+}
+
+void GeckoEditableSupport::FlushIMEChanges(FlushChangesFlag aFlags) {
+  // Only send change notifications if we are *not* masking events,
+  // i.e. if we have a focused editor,
+  NS_ENSURE_TRUE_VOID(!mIMEMaskEventsCount);
+
+  if (mIMEDelaySynchronizeReply && mIMEActiveCompositionCount > 0) {
+    // We are still expecting more composition events to be handled. Once
+    // that happens, FlushIMEChanges will be called again.
+    return;
+  }
+
+  nsCOMPtr<nsIWidget> widget = GetWidget();
+  NS_ENSURE_TRUE_VOID(widget);
+
+  struct TextRecord {
+    TextRecord() : start(-1), oldEnd(-1), newEnd(-1) {}
+
+    bool IsValid() const { return start >= 0; }
+
+    nsString text;
+    int32_t start;
+    int32_t oldEnd;
+    int32_t newEnd;
+  };
+  TextRecord textTransaction;
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  bool causedOnlyByComposition = mIMEPendingTextChange.IsValid() &&
+                                 mIMEPendingTextChange.mCausedOnlyByComposition;
+  mIMETextChangedDuringFlush = false;
+
+  auto shouldAbort = [=](bool aForce) -> bool {
+    if (!aForce && !mIMETextChangedDuringFlush) {
+      return false;
+    }
+    // A query event could have triggered more text changes to come in, as
+    // indicated by our flag. If that happens, try flushing IME changes
+    // again.
+    if (aFlags == FLUSH_FLAG_NONE) {
+      FlushIMEChanges(FLUSH_FLAG_RETRY);
+    } else {
+      // Don't retry if already retrying, to avoid infinite loops.
+      __android_log_print(ANDROID_LOG_WARN, "GeckoEditableSupport",
+                          "Already retrying IME flush");
+    }
+    return true;
+  };
+
+  if (mIMEPendingTextChange.IsValid() &&
+      (mIMEPendingTextChange.mStartOffset !=
+           mIMEPendingTextChange.mRemovedEndOffset ||
+       mIMEPendingTextChange.mStartOffset !=
+           mIMEPendingTextChange.mAddedEndOffset)) {
+    WidgetQueryContentEvent queryTextContentEvent(true, eQueryTextContent,
+                                                  widget);
+
+    if (mIMEPendingTextChange.mAddedEndOffset !=
+        mIMEPendingTextChange.mStartOffset) {
+      queryTextContentEvent.InitForQueryTextContent(
+          mIMEPendingTextChange.mStartOffset,
+          mIMEPendingTextChange.mAddedEndOffset -
+              mIMEPendingTextChange.mStartOffset);
+      widget->DispatchEvent(&queryTextContentEvent, status);
+
+      if (shouldAbort(NS_WARN_IF(queryTextContentEvent.Failed()))) {
+        return;
+      }
+
+      textTransaction.text = queryTextContentEvent.mReply->DataRef();
+    }
+
+    textTransaction.start =
+        static_cast<int32_t>(mIMEPendingTextChange.mStartOffset);
+    textTransaction.oldEnd =
+        static_cast<int32_t>(mIMEPendingTextChange.mRemovedEndOffset);
+    textTransaction.newEnd =
+        static_cast<int32_t>(mIMEPendingTextChange.mAddedEndOffset);
+  }
+
+  int32_t selStart = -1;
+  int32_t selEnd = -1;
+
+  if (mIMESelectionChanged) {
+    if (mCachedSelection.IsValid()) {
+      selStart = mCachedSelection.mStartOffset;
+      selEnd = mCachedSelection.mEndOffset;
+    } else {
+      // XXX Unfortunately we don't know current selection via selection
+      //     change notification.
+      //     eQuerySelectedText might be newer data than text change data.
+      //     It means that GeckoEditableChild.onSelectionChange may throw
+      //     IllegalArgumentException since we don't merge with newer text
+      //     change.
+      WidgetQueryContentEvent querySelectedTextEvent(true, eQuerySelectedText,
+                                                     widget);
+      widget->DispatchEvent(&querySelectedTextEvent, status);
+
+      if (shouldAbort(
+              NS_WARN_IF(querySelectedTextEvent.DidNotFindSelection()))) {
+        return;
+      }
+
+      selStart =
+          static_cast<int32_t>(querySelectedTextEvent.mReply->AnchorOffset());
+      selEnd =
+          static_cast<int32_t>(querySelectedTextEvent.mReply->FocusOffset());
+    }
+
+    if (aFlags == FLUSH_FLAG_RECOVER && textTransaction.IsValid()) {
+      // Sometimes we get out-of-bounds selection during recovery.
+      // Limit the offsets so we don't crash.
+      const int32_t end = textTransaction.start + textTransaction.text.Length();
+      selStart = std::min(selStart, end);
+      selEnd = std::min(selEnd, end);
+    }
+  }
+
+  JNIEnv* const env = jni::GetGeckoThreadEnv();
+  auto flushOnException = [=]() -> bool {
+    if (!env->ExceptionCheck()) {
+      return false;
+    }
+    if (aFlags != FLUSH_FLAG_RECOVER) {
+      // First time seeing an exception; try flushing text.
+      env->ExceptionClear();
+      __android_log_print(ANDROID_LOG_WARN, "GeckoEditableSupport",
+                          "Recovering from IME exception");
+      FlushIMEText(FLUSH_FLAG_RECOVER);
+    } else {
+      // Give up because we've already tried.
+#ifdef RELEASE_OR_BETA
+      env->ExceptionClear();
+#else
+      MOZ_CATCH_JNI_EXCEPTION(env);
+#endif
+    }
+    return true;
+  };
+
+  // Commit the text change and selection change transaction.
+  mIMEPendingTextChange.Clear();
+
+  if (textTransaction.IsValid()) {
+    mEditable->OnTextChange(textTransaction.text, textTransaction.start,
+                            textTransaction.oldEnd, textTransaction.newEnd,
+                            causedOnlyByComposition);
+    if (flushOnException()) {
+      return;
+    }
+  }
+
+  while (mIMEDelaySynchronizeReply && mIMEActiveSynchronizeCount) {
+    mIMEActiveSynchronizeCount--;
+    mEditable->NotifyIME(EditableListener::NOTIFY_IME_REPLY_EVENT);
+  }
+  mIMEDelaySynchronizeReply = false;
+  mIMEActiveSynchronizeCount = 0;
+  mIMEActiveCompositionCount = 0;
+
+  if (mIMESelectionChanged) {
+    mIMESelectionChanged = false;
+    if (mDispatcher) {
+      // mCausedOnlyByComposition may be true on committing text.
+      // So even if true, there is no composition.
+      causedOnlyByComposition &= mDispatcher->IsComposing();
+    }
+    mEditable->OnSelectionChange(selStart, selEnd, causedOnlyByComposition);
+    flushOnException();
+  }
+}
+
+void GeckoEditableSupport::FlushIMEText(FlushChangesFlag aFlags) {
+  NS_WARNING_ASSERTION(
+      !mIMEDelaySynchronizeReply || !mIMEActiveCompositionCount,
+      "Cannot synchronize Java text with Gecko text");
+
+  // Notify Java of the newly focused content
+  mIMEPendingTextChange.Clear();
+  mIMESelectionChanged = true;
+
+  // Use 'INT32_MAX / 2' here because subsequent text changes might combine
+  // with this text change, and overflow might occur if we just use
+  // INT32_MAX.
+  IMENotification notification(NOTIFY_IME_OF_TEXT_CHANGE);
+  notification.mTextChangeData.mStartOffset = 0;
+  notification.mTextChangeData.mRemovedEndOffset = INT32_MAX / 2;
+  notification.mTextChangeData.mAddedEndOffset = INT32_MAX / 2;
+  NotifyIME(mDispatcher, notification);
+
+  FlushIMEChanges(aFlags);
+}
+
+void GeckoEditableSupport::UpdateCompositionRects() {
+  nsCOMPtr<nsIWidget> widget = GetWidget();
+  RefPtr<TextComposition> composition(GetComposition());
+  NS_ENSURE_TRUE_VOID(mDispatcher && widget);
+
+  jni::ObjectArray::LocalRef rects;
+  if (composition) {
+    nsEventStatus status = nsEventStatus_eIgnore;
+    uint32_t offset = composition->NativeOffsetOfStartComposition();
+    WidgetQueryContentEvent queryTextRectsEvent(true, eQueryTextRectArray,
+                                                widget);
+    queryTextRectsEvent.InitForQueryTextRectArray(
+        offset, composition->String().Length());
+    widget->DispatchEvent(&queryTextRectsEvent, status);
+    rects = ConvertRectArrayToJavaRectFArray(
+        queryTextRectsEvent.Succeeded()
+            ? queryTextRectsEvent.mReply->mRectArray
+            : CopyableTArray<mozilla::LayoutDeviceIntRect>());
+  } else {
+    rects = ConvertRectArrayToJavaRectFArray(
+        CopyableTArray<mozilla::LayoutDeviceIntRect>());
+  }
+
+  WidgetQueryContentEvent queryCaretRectEvent(true, eQueryCaretRect, widget);
+  WidgetQueryContentEvent::Options options;
+  options.mRelativeToInsertionPoint = true;
+  queryCaretRectEvent.InitForQueryCaretRect(0, options);
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  widget->DispatchEvent(&queryCaretRectEvent, status);
+  auto caretRect =
+      queryCaretRectEvent.Succeeded()
+          ? java::sdk::RectF::New(queryCaretRectEvent.mReply->mRect.x,
+                                  queryCaretRectEvent.mReply->mRect.y,
+                                  queryCaretRectEvent.mReply->mRect.XMost(),
+                                  queryCaretRectEvent.mReply->mRect.YMost())
+          : java::sdk::RectF::New();
+
+  mEditable->UpdateCompositionRects(rects, caretRect);
+}
+
+void GeckoEditableSupport::OnImeSynchronize() {
+  AutoGeckoEditableBlocker blocker(this);
+
+  if (mIMEDelaySynchronizeReply) {
+    // If we are waiting for other events to reply,
+    // queue this reply as well.
+    mIMEActiveSynchronizeCount++;
+    return;
+  }
+  if (!mIMEMaskEventsCount) {
+    FlushIMEChanges();
+  }
+  mEditable->NotifyIME(EditableListener::NOTIFY_IME_REPLY_EVENT);
+}
+
+void GeckoEditableSupport::OnImeReplaceText(int32_t aStart, int32_t aEnd,
+                                            jni::String::Param aText) {
+  AutoGeckoEditableBlocker blocker(this);
+
+  if (DoReplaceText(aStart, aEnd, aText)) {
+    mIMEDelaySynchronizeReply = true;
+  }
+
+  OnImeSynchronize();
+}
+
+bool GeckoEditableSupport::DoReplaceText(int32_t aStart, int32_t aEnd,
+                                         jni::String::Param aText) {
+  ALOGIME("IME: IME_REPLACE_TEXT: text=\"%s\"",
+          NS_ConvertUTF16toUTF8(aText->ToString()).get());
+
+  // Return true if processed and we should reply to the OnImeReplaceText
+  // event later. Return false if _not_ processed and we should reply to the
+  // OnImeReplaceText event now.
+
+  if (mIMEMaskEventsCount > 0) {
+    // Not focused; still reply to events, but don't do anything else.
+    return false;
+  }
+
+  if (nsWindow* window = GetNsWindow()) {
+    window->UserActivity();
+  }
+
+  /*
+      Replace text in Gecko thread from aStart to aEnd with the string text.
+  */
+  nsCOMPtr<nsIWidget> widget = GetWidget();
+  NS_ENSURE_TRUE(mDispatcher && widget, false);
+  NS_ENSURE_SUCCESS(BeginInputTransaction(mDispatcher), false);
+
+  RefPtr<TextComposition> composition(GetComposition());
+  MOZ_ASSERT(!composition || !composition->IsEditorHandlingEvent());
+
+  nsString string(aText->ToString());
+  const bool composing = !mIMERanges->IsEmpty();
+  nsEventStatus status = nsEventStatus_eIgnore;
+  bool textChanged = composing;
+  // Whether deleting content before setting or committing composition text.
+  bool performDeletion = false;
+  // Dispatch composition start to set current composition.
+  bool needDispatchCompositionStart = false;
+
+  if (!mIMEKeyEvents.IsEmpty() || !composition || !mDispatcher->IsComposing() ||
+      uint32_t(aStart) != composition->NativeOffsetOfStartComposition() ||
+      uint32_t(aEnd) != composition->NativeOffsetOfStartComposition() +
+                            composition->String().Length()) {
+    // Only start a new composition if we have key events,
+    // if we don't have an existing composition, or
+    // the replaced text does not match our composition.
+    textChanged |= RemoveComposition();
+
+#ifdef NIGHTLY_BUILD
+    {
+      nsEventStatus status = nsEventStatus_eIgnore;
+      WidgetQueryContentEvent querySelectedTextEvent(true, eQuerySelectedText,
+                                                     widget);
+      widget->DispatchEvent(&querySelectedTextEvent, status);
+      if (querySelectedTextEvent.Succeeded()) {
+        ALOGIME(
+            "IME: Current selection: %s",
+            ToString(querySelectedTextEvent.mReply->mOffsetAndData).c_str());
+      }
+    }
+#endif
+
+    // If aStart or aEnd is negative value, we use current selection instead
+    // of updating the selection.
+    if (aStart >= 0 && aEnd >= 0) {
+      // Use text selection to set target position(s) for
+      // insert, or replace, of text.
+      WidgetSelectionEvent event(true, eSetSelection, widget);
+      event.mOffset = uint32_t(aStart);
+      event.mLength = uint32_t(aEnd - aStart);
+      event.mExpandToClusterBoundary = false;
+      event.mReason = nsISelectionListener::IME_REASON;
+      widget->DispatchEvent(&event, status);
+    }
+
+    if (!mIMEKeyEvents.IsEmpty()) {
+      bool ignoreNextKeyPress = false;
+      for (uint32_t i = 0; i < mIMEKeyEvents.Length(); i++) {
+        const auto event = mIMEKeyEvents[i]->AsKeyboardEvent();
+        // widget for duplicated events is initially nullptr.
+        event->mWidget = widget;
+
+        status = nsEventStatus_eIgnore;
+        if (event->mMessage != eKeyPress) {
+          mDispatcher->DispatchKeyboardEvent(event->mMessage, *event, status);
+          // Skip default processing. It means that next key press shouldn't
+          // be dispatched.
+          ignoreNextKeyPress = event->mMessage == eKeyDown &&
+                               status == nsEventStatus_eConsumeNoDefault;
+        } else {
+          if (ignoreNextKeyPress) {
+            // Don't dispatch key press since previous key down is consumed.
+            ignoreNextKeyPress = false;
+            continue;
+          }
+          mDispatcher->MaybeDispatchKeypressEvents(*event, status);
+          if (status == nsEventStatus_eConsumeNoDefault) {
+            textChanged = true;
+          }
+        }
+        if (!mDispatcher || widget->Destroyed()) {
+          // Don't wait for any text change event.
+          textChanged = false;
+          break;
+        }
+      }
+      mIMEKeyEvents.Clear();
+      return textChanged;
+    }
+
+    if (aStart != aEnd) {
+      if (composing) {
+        // Actually Gecko doesn't start composition, so it is unnecessary to
+        // delete content before setting composition string.
+        needDispatchCompositionStart = true;
+      } else {
+        // Perform a deletion first.
+        performDeletion = true;
+      }
+    }
+  } else if (composition->String().Equals(string)) {
+    // If the new text is the same as the existing composition text,
+    // the NS_COMPOSITION_CHANGE event does not generate a text
+    // change notification. However, the Java side still expects
+    // one, so we manually generate a notification.
+    //
+    // Also, since this is IME change, we have to set mCausedOnlyByComposition.
+    IMENotification::TextChangeData dummyChange(aStart, aEnd, aEnd, true,
+                                                false);
+    PostFlushIMEChanges();
+    mIMESelectionChanged = true;
+    AddIMETextChange(dummyChange);
+    textChanged = true;
+  }
+
+  SendIMEDummyKeyEvent(widget, eKeyDown);
+  if (!mDispatcher || widget->Destroyed()) {
+    return false;
+  }
+
+  if (needDispatchCompositionStart) {
+    // StartComposition sets composition string from selected string.
+    nsEventStatus status = nsEventStatus_eIgnore;
+    mDispatcher->StartComposition(status);
+    if (!mDispatcher || widget->Destroyed()) {
+      return false;
+    }
+  } else if (performDeletion) {
+    WidgetContentCommandEvent event(true, eContentCommandDelete, widget);
+    widget->DispatchEvent(&event, status);
+    if (!mDispatcher || widget->Destroyed()) {
+      return false;
+    }
+    textChanged = true;
+  }
+
+  if (composing) {
+    mDispatcher->SetPendingComposition(string, mIMERanges);
+    mDispatcher->FlushPendingComposition(status);
+    mIMEActiveCompositionCount++;
+    // Ensure IME ranges are empty.
+    mIMERanges->Clear();
+  } else if (!string.IsEmpty() || mDispatcher->IsComposing()) {
+    mDispatcher->CommitComposition(status, &string);
+    mIMEActiveCompositionCount++;
+    textChanged = true;
+  }
+  if (!mDispatcher || widget->Destroyed()) {
+    return false;
+  }
+
+  SendIMEDummyKeyEvent(widget, eKeyUp);
+  // Widget may be destroyed after dispatching the above event.
+
+  return textChanged;
+}
+
+void GeckoEditableSupport::OnImeAddCompositionRange(
+    int32_t aStart, int32_t aEnd, int32_t aRangeType, int32_t aRangeStyle,
+    int32_t aRangeLineStyle, bool aRangeBoldLine, int32_t aRangeForeColor,
+    int32_t aRangeBackColor, int32_t aRangeLineColor) {
+  AutoGeckoEditableBlocker blocker(this);
+
+  if (mIMEMaskEventsCount > 0) {
+    // Not focused.
+    return;
+  }
+
+  TextRange range;
+  range.mStartOffset = aStart;
+  range.mEndOffset = aEnd;
+  range.mRangeType = ToTextRangeType(aRangeType);
+  range.mRangeStyle.mDefinedStyles = aRangeStyle;
+  range.mRangeStyle.mLineStyle = TextRangeStyle::ToLineStyle(aRangeLineStyle);
+  range.mRangeStyle.mIsBoldLine = aRangeBoldLine;
+  range.mRangeStyle.mForegroundColor =
+      ConvertAndroidColor(uint32_t(aRangeForeColor));
+  range.mRangeStyle.mBackgroundColor =
+      ConvertAndroidColor(uint32_t(aRangeBackColor));
+  range.mRangeStyle.mUnderlineColor =
+      ConvertAndroidColor(uint32_t(aRangeLineColor));
+  mIMERanges->AppendElement(range);
+}
+
+void GeckoEditableSupport::OnImeUpdateComposition(int32_t aStart, int32_t aEnd,
+                                                  int32_t aFlags) {
+  AutoGeckoEditableBlocker blocker(this);
+
+  if (DoUpdateComposition(aStart, aEnd, aFlags)) {
+    mIMEDelaySynchronizeReply = true;
+  }
+}
+
+bool GeckoEditableSupport::DoUpdateComposition(int32_t aStart, int32_t aEnd,
+                                               int32_t aFlags) {
+  if (mIMEMaskEventsCount > 0) {
+    // Not focused.
+    return false;
+  }
+
+  nsCOMPtr<nsIWidget> widget = GetWidget();
+  nsEventStatus status = nsEventStatus_eIgnore;
+  NS_ENSURE_TRUE(mDispatcher && widget, false);
+
+  const bool keepCurrent =
+      !!(aFlags & java::GeckoEditableChild::FLAG_KEEP_CURRENT_COMPOSITION);
+
+  // A composition with no ranges means we want to set the selection.
+  if (mIMERanges->IsEmpty()) {
+    if (keepCurrent && mDispatcher->IsComposing()) {
+      // Don't set selection if we want to keep current composition.
+      return false;
+    }
+
+    MOZ_ASSERT(aStart >= 0 && aEnd >= 0);
+    const bool compositionChanged = RemoveComposition();
+
+    WidgetSelectionEvent selEvent(true, eSetSelection, widget);
+    selEvent.mOffset = std::min(aStart, aEnd);
+    selEvent.mLength = std::max(aStart, aEnd) - selEvent.mOffset;
+    selEvent.mReversed = aStart > aEnd;
+    selEvent.mExpandToClusterBoundary = false;
+    widget->DispatchEvent(&selEvent, status);
+    return compositionChanged;
+  }
+
+  /**
+   * Update the composition from aStart to aEnd using information from added
+   * ranges. This is only used for visual indication and does not affect the
+   * text content.  Only the offsets are specified and not the text content
+   * to eliminate the possibility of this event altering the text content
+   * unintentionally.
+   */
+  nsString string;
+  RefPtr<TextComposition> composition(GetComposition());
+  MOZ_ASSERT(!composition || !composition->IsEditorHandlingEvent());
+
+  if (!composition || !mDispatcher->IsComposing() ||
+      uint32_t(aStart) != composition->NativeOffsetOfStartComposition() ||
+      uint32_t(aEnd) != composition->NativeOffsetOfStartComposition() +
+                            composition->String().Length()) {
+    if (keepCurrent) {
+      // Don't start a new composition if we want to keep the current one.
+      mIMERanges->Clear();
+      return false;
+    }
+
+    // Only start new composition if we don't have an existing one,
+    // or if the existing composition doesn't match the new one.
+    RemoveComposition();
+
+    {
+      WidgetSelectionEvent event(true, eSetSelection, widget);
+      event.mOffset = uint32_t(aStart);
+      event.mLength = uint32_t(aEnd - aStart);
+      event.mExpandToClusterBoundary = false;
+      event.mReason = nsISelectionListener::IME_REASON;
+      widget->DispatchEvent(&event, status);
+    }
+
+    {
+      WidgetQueryContentEvent querySelectedTextEvent(true, eQuerySelectedText,
+                                                     widget);
+      widget->DispatchEvent(&querySelectedTextEvent, status);
+      MOZ_ASSERT(querySelectedTextEvent.Succeeded());
+      if (querySelectedTextEvent.FoundSelection()) {
+        string = querySelectedTextEvent.mReply->DataRef();
+      }
+    }
+  } else {
+    // If the new composition matches the existing composition,
+    // reuse the old composition.
+    string = composition->String();
+  }
+
+  ALOGIME("IME: IME_SET_TEXT: text=\"%s\", length=%zu, range=%zu",
+          NS_ConvertUTF16toUTF8(string).get(), string.Length(),
+          mIMERanges->Length());
+
+  if (NS_WARN_IF(NS_FAILED(BeginInputTransaction(mDispatcher)))) {
+    mIMERanges->Clear();
+    return false;
+  }
+  mDispatcher->SetPendingComposition(string, mIMERanges);
+  mDispatcher->FlushPendingComposition(status);
+  mIMEActiveCompositionCount++;
+  mIMERanges->Clear();
+  return true;
+}
+
+void GeckoEditableSupport::OnImeRequestCursorUpdates(int aRequestMode) {
+  AutoGeckoEditableBlocker blocker(this);
+
+  if (aRequestMode == EditableClient::ONE_SHOT) {
+    UpdateCompositionRects();
+    return;
+  }
+
+  mIMEMonitorCursor = (aRequestMode == EditableClient::START_MONITOR);
+}
+
+class MOZ_STACK_CLASS AutoSelectionRestore final {
+ public:
+  explicit AutoSelectionRestore(nsIWidget* widget,
+                                TextEventDispatcher* dispatcher)
+      : mWidget(widget), mDispatcher(dispatcher) {
+    MOZ_ASSERT(widget);
+    if (!dispatcher || !dispatcher->IsComposing()) {
+      mOffset = UINT32_MAX;
+      mLength = UINT32_MAX;
+      return;
+    }
+    WidgetQueryContentEvent querySelectedTextEvent(true, eQuerySelectedText,
+                                                   widget);
+    nsEventStatus status = nsEventStatus_eIgnore;
+    widget->DispatchEvent(&querySelectedTextEvent, status);
+    if (querySelectedTextEvent.DidNotFindSelection()) {
+      mOffset = UINT32_MAX;
+      mLength = UINT32_MAX;
+      return;
+    }
+
+    mOffset = querySelectedTextEvent.mReply->StartOffset();
+    mLength = querySelectedTextEvent.mReply->DataLength();
+  }
+
+  ~AutoSelectionRestore() {
+    if (mWidget->Destroyed() || mOffset == UINT32_MAX) {
+      return;
+    }
+
+    WidgetSelectionEvent selection(true, eSetSelection, mWidget);
+    selection.mOffset = mOffset;
+    selection.mLength = mLength;
+    selection.mExpandToClusterBoundary = false;
+    selection.mReason = nsISelectionListener::IME_REASON;
+    nsEventStatus status = nsEventStatus_eIgnore;
+    mWidget->DispatchEvent(&selection, status);
+  }
+
+ private:
+  nsCOMPtr<nsIWidget> mWidget;
+  RefPtr<TextEventDispatcher> mDispatcher;
+  uint32_t mOffset;
+  uint32_t mLength;
+};
+
+void GeckoEditableSupport::OnImeRequestCommit() {
+  AutoGeckoEditableBlocker blocker(this);
+
+  if (mIMEMaskEventsCount > 0) {
+    // Not focused.
+    return;
+  }
+
+  nsCOMPtr<nsIWidget> widget = GetWidget();
+  if (NS_WARN_IF(!widget)) {
+    return;
+  }
+
+  AutoSelectionRestore restore(widget, mDispatcher);
+
+  RemoveComposition(COMMIT_IME_COMPOSITION);
+}
+
+void GeckoEditableSupport::AsyncNotifyIME(int32_t aNotification) {
+  RefPtr<GeckoEditableSupport> self(this);
+
+  nsAppShell::PostEvent([this, self, aNotification] {
+    if (!mIMEMaskEventsCount) {
+      mEditable->NotifyIME(aNotification);
+    }
+  });
+}
+
+nsresult GeckoEditableSupport::NotifyIME(
+    TextEventDispatcher* aTextEventDispatcher,
+    const IMENotification& aNotification) {
+  MOZ_ASSERT(mEditable);
+
+  switch (aNotification.mMessage) {
+    case REQUEST_TO_COMMIT_COMPOSITION: {
+      ALOGIME("IME: REQUEST_TO_COMMIT_COMPOSITION");
+
+      RemoveComposition(COMMIT_IME_COMPOSITION);
+      AsyncNotifyIME(EditableListener::NOTIFY_IME_TO_COMMIT_COMPOSITION);
+      break;
+    }
+
+    case REQUEST_TO_CANCEL_COMPOSITION: {
+      ALOGIME("IME: REQUEST_TO_CANCEL_COMPOSITION");
+
+      RemoveComposition(CANCEL_IME_COMPOSITION);
+      AsyncNotifyIME(EditableListener::NOTIFY_IME_TO_CANCEL_COMPOSITION);
+      break;
+    }
+
+    case NOTIFY_IME_OF_FOCUS: {
+      ALOGIME("IME: NOTIFY_IME_OF_FOCUS");
+
+      mIMEFocusCount++;
+
+      RefPtr<GeckoEditableSupport> self(this);
+      RefPtr<TextEventDispatcher> dispatcher = aTextEventDispatcher;
+
+      // Post an event because we have to flush the text before sending a
+      // focus event, and we may not be able to flush text during the
+      // NotifyIME call.
+      nsAppShell::PostEvent([this, self, dispatcher] {
+        nsCOMPtr<nsIWidget> widget = dispatcher->GetWidget();
+
+        --mIMEMaskEventsCount;
+        if (!mIMEFocusCount || !widget || widget->Destroyed()) {
+          return;
+        }
+
+        mEditable->NotifyIME(EditableListener::NOTIFY_IME_OF_TOKEN);
+
+        if (mIsRemote) {
+          if (!mEditableAttached) {
+            // Re-attach on focus; see OnRemovedFrom().
+            jni::NativeWeakPtrHolder<GeckoEditableSupport>::AttachExisting(
+                mEditable, do_AddRef(this));
+            mEditableAttached = true;
+          }
+          // Because GeckoEditableSupport in content process doesn't
+          // manage the active input context, we need to retrieve the
+          // input context from the widget, for use by
+          // OnImeReplaceText.
+          mInputContext = widget->GetInputContext();
+        }
+        mDispatcher = dispatcher;
+        mIMEKeyEvents.Clear();
+
+        mCachedSelection.Reset();
+
+        mIMEDelaySynchronizeReply = false;
+        mIMEActiveCompositionCount = 0;
+        FlushIMEText();
+
+        // IME will call requestCursorUpdates after getting context.
+        // So reset cursor update mode before getting context.
+        mIMEMonitorCursor = false;
+
+        mEditable->NotifyIME(EditableListener::NOTIFY_IME_OF_FOCUS);
+      });
+      break;
+    }
+
+    case NOTIFY_IME_OF_BLUR: {
+      ALOGIME("IME: NOTIFY_IME_OF_BLUR");
+
+      mIMEFocusCount--;
+      MOZ_ASSERT(mIMEFocusCount >= 0);
+
+      RefPtr<GeckoEditableSupport> self(this);
+      nsAppShell::PostEvent([this, self] {
+        if (!mIMEFocusCount) {
+          mIMEDelaySynchronizeReply = false;
+          mIMEActiveSynchronizeCount = 0;
+          mIMEActiveCompositionCount = 0;
+          mInputContext.ShutDown();
+          mEditable->NotifyIME(EditableListener::NOTIFY_IME_OF_BLUR);
+          OnRemovedFrom(mDispatcher);
+        }
+      });
+
+      // Mask events because we lost focus. Unmask on the next focus.
+      mIMEMaskEventsCount++;
+      break;
+    }
+
+    case NOTIFY_IME_OF_SELECTION_CHANGE: {
+      ALOGIME("IME: NOTIFY_IME_OF_SELECTION_CHANGE: SelectionChangeData=%s",
+              ToString(aNotification.mSelectionChangeData).c_str());
+
+      if (aNotification.mSelectionChangeData.HasRange()) {
+        mCachedSelection.mStartOffset = static_cast<int32_t>(
+            aNotification.mSelectionChangeData.AnchorOffset());
+        mCachedSelection.mEndOffset = static_cast<int32_t>(
+            aNotification.mSelectionChangeData.FocusOffset());
+      } else {
+        mCachedSelection.Reset();
+      }
+
+      PostFlushIMEChanges();
+      mIMESelectionChanged = true;
+      break;
+    }
+
+    case NOTIFY_IME_OF_TEXT_CHANGE: {
+      ALOGIME("IME: NOTIFY_IME_OF_TEXT_CHANGE: TextChangeData=%s",
+              ToString(aNotification.mTextChangeData).c_str());
+
+      /* Make sure Java's selection is up-to-date */
+      PostFlushIMEChanges();
+      mIMESelectionChanged = true;
+      AddIMETextChange(aNotification.mTextChangeData);
+      break;
+    }
+
+    case NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED: {
+      ALOGIME("IME: NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED");
+
+      // NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED isn't sent per IME call.
+      // Receiving this event means that Gecko has already handled all IME
+      // composing events in queue.
+      //
+      if (mIsRemote) {
+        OnNotifyIMEOfCompositionEventHandled();
+      } else {
+        // Also, when receiving this event, mIMEDelaySynchronizeReply won't
+        // update yet on non-e10s case since IME event is posted before updating
+        // it. So we have to delay handling of this event.
+        RefPtr<GeckoEditableSupport> self(this);
+        nsAppShell::PostEvent(
+            [this, self] { OnNotifyIMEOfCompositionEventHandled(); });
+      }
+      break;
+    }
+
+    default:
+      break;
+  }
+  return NS_OK;
+}
+
+void GeckoEditableSupport::OnNotifyIMEOfCompositionEventHandled() {
+  // NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED may be merged with multiple events,
+  // so reset count.
+  mIMEActiveCompositionCount = 0;
+  if (mIMEDelaySynchronizeReply) {
+    FlushIMEChanges();
+  }
+
+  // Hardware keyboard support requires each string rect.
+  if (mIMEMonitorCursor) {
+    UpdateCompositionRects();
+  }
+}
+
+void GeckoEditableSupport::OnRemovedFrom(
+    TextEventDispatcher* aTextEventDispatcher) {
+  mDispatcher = nullptr;
+
+  if (mIsRemote && mEditable->HasEditableParent()) {
+    // When we're remote, detach every time.
+    OnWeakNonIntrusiveDetach(NS_NewRunnableFunction(
+        "GeckoEditableSupport::OnRemovedFrom",
+        [editable = java::GeckoEditableChild::GlobalRef(mEditable)] {
+          DisposeNative(editable);
+        }));
+  }
+}
+
+void GeckoEditableSupport::WillDispatchKeyboardEvent(
+    TextEventDispatcher* aTextEventDispatcher,
+    WidgetKeyboardEvent& aKeyboardEvent, uint32_t aIndexOfKeypress,
+    void* aData) {}
+
+NS_IMETHODIMP_(IMENotificationRequests)
+GeckoEditableSupport::GetIMENotificationRequests() {
+  return IMENotificationRequests(IMENotificationRequests::NOTIFY_TEXT_CHANGE);
+}
+
+static bool ShouldKeyboardDismiss(const nsAString& aInputType,
+                                  const nsAString& aInputMode) {
+  // Some input type uses the prompt to input value. So it is unnecessary to
+  // show software keyboard.
+  return aInputMode.EqualsLiteral("none") || aInputType.EqualsLiteral("date") ||
+         aInputType.EqualsLiteral("time") ||
+         aInputType.EqualsLiteral("month") ||
+         aInputType.EqualsLiteral("week") ||
+         aInputType.EqualsLiteral("datetime-local");
+}
+
+void GeckoEditableSupport::SetInputContext(const InputContext& aContext,
+                                           const InputContextAction& aAction) {
+  // SetInputContext is called from chrome process only
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(mEditable);
+
+  ALOGIME(
+      "IME: SetInputContext: aContext=%s, "
+      "aAction={mCause=%s, mFocusChange=%s}",
+      ToString(aContext).c_str(), ToString(aAction.mCause).c_str(),
+      ToString(aAction.mFocusChange).c_str());
+
+  mInputContext = aContext;
+
+  if (mInputContext.mIMEState.mEnabled != IMEEnabled::Disabled &&
+      !ShouldKeyboardDismiss(mInputContext.mHTMLInputType,
+                             mInputContext.mHTMLInputMode) &&
+      aAction.UserMightRequestOpenVKB()) {
+    // Don't reset keyboard when we should simply open the vkb
+    mEditable->NotifyIME(EditableListener::NOTIFY_IME_OPEN_VKB);
+    return;
+  }
+
+  // Post an event to keep calls in order relative to NotifyIME.
+  nsAppShell::PostEvent([this, self = RefPtr<GeckoEditableSupport>(this),
+                         context = mInputContext, action = aAction] {
+    nsCOMPtr<nsIWidget> widget = GetWidget();
+
+    if (!widget || widget->Destroyed()) {
+      return;
+    }
+    NotifyIMEContext(context, action);
+  });
+}
+
+void GeckoEditableSupport::NotifyIMEContext(const InputContext& aContext,
+                                            const InputContextAction& aAction) {
+  const bool inPrivateBrowsing = aContext.mInPrivateBrowsing;
+  // isUserAction is used whether opening virtual keyboard. But long press
+  // shouldn't open it.
+  const bool isUserAction =
+      aAction.mCause != InputContextAction::CAUSE_LONGPRESS &&
+      !(aAction.mCause == InputContextAction::CAUSE_UNKNOWN_CHROME &&
+        aContext.mIMEState.mEnabled == IMEEnabled::Enabled) &&
+      (aAction.IsHandlingUserInput() || aContext.mHasHandledUserInput);
+  const int32_t flags =
+      (inPrivateBrowsing ? EditableListener::IME_FLAG_PRIVATE_BROWSING : 0) |
+      (isUserAction ? EditableListener::IME_FLAG_USER_ACTION : 0) |
+      (aAction.mFocusChange == InputContextAction::FOCUS_NOT_CHANGED
+           ? EditableListener::IME_FOCUS_NOT_CHANGED
+           : 0);
+
+  mEditable->NotifyIMEContext(static_cast<int32_t>(aContext.mIMEState.mEnabled),
+                              aContext.mHTMLInputType, aContext.mHTMLInputMode,
+                              aContext.mActionHint, aContext.mAutocapitalize,
+                              flags);
+}
+
+InputContext GeckoEditableSupport::GetInputContext() {
+  // GetInputContext is called from chrome process only
+  MOZ_ASSERT(XRE_IsParentProcess());
+  InputContext context = mInputContext;
+  context.mIMEState.mOpen = IMEState::OPEN_STATE_NOT_SUPPORTED;
+  return context;
+}
+
+void GeckoEditableSupport::TransferParent(jni::Object::Param aEditableParent) {
+  AutoGeckoEditableBlocker blocker(this);
+
+  mEditable->SetParent(aEditableParent);
+
+  // If we are already focused, make sure the new parent has our token
+  // and focus information, so it can accept additional calls from us.
+  if (mIMEFocusCount > 0) {
+    mEditable->NotifyIME(EditableListener::NOTIFY_IME_OF_TOKEN);
+    if (mIsRemote) {
+      // GeckoEditableSupport::SetInputContext is called on chrome process
+      // only, so mInputContext may be still invalid since it is set after
+      // we have gotton focus.
+      RefPtr<GeckoEditableSupport> self(this);
+      nsAppShell::PostEvent([self = std::move(self)] {
+        NS_WARNING_ASSERTION(
+            self->mDispatcher,
+            "Text dispatcher is still null. Why don't we get focus yet?");
+        self->NotifyIMEContext(self->mInputContext, InputContextAction());
+      });
+    } else {
+      NotifyIMEContext(mInputContext, InputContextAction());
+    }
+    mEditable->NotifyIME(EditableListener::NOTIFY_IME_OF_FOCUS);
+    // We have focus, so don't destroy editable child.
+    return;
+  }
+
+  if (mIsRemote && !mDispatcher) {
+    // Detach now if we were only attached temporarily.
+    OnRemovedFrom(/* dispatcher */ nullptr);
+  }
+}
+
+void GeckoEditableSupport::SetOnBrowserChild(dom::BrowserChild* aBrowserChild) {
+  MOZ_ASSERT(!XRE_IsParentProcess());
+  NS_ENSURE_TRUE_VOID(aBrowserChild);
+
+  const dom::ContentChild* const contentChild =
+      dom::ContentChild::GetSingleton();
+  RefPtr<widget::PuppetWidget> widget(aBrowserChild->WebWidget());
+  NS_ENSURE_TRUE_VOID(contentChild && widget);
+
+  // Get the content/tab ID in order to get the correct
+  // IGeckoEditableParent object, which GeckoEditableChild uses to
+  // communicate with the parent process.
+  const uint64_t contentId = contentChild->GetID();
+  const uint64_t tabId = aBrowserChild->GetTabId();
+  NS_ENSURE_TRUE_VOID(contentId && tabId);
+
+  RefPtr<widget::TextEventDispatcherListener> listener =
+      widget->GetNativeTextEventDispatcherListener();
+
+  if (!listener ||
+      listener.get() ==
+          static_cast<widget::TextEventDispatcherListener*>(widget)) {
+    // We need to set a new listener.
+    const auto editableChild = java::GeckoEditableChild::New(
+        /* parent */ nullptr, /* default */ false);
+
+    // Temporarily attach so we can receive the initial editable parent.
+    auto editableSupport =
+        jni::NativeWeakPtrHolder<GeckoEditableSupport>::Attach(editableChild,
+                                                               editableChild);
+    auto accEditableSupport(editableSupport.Access());
+    MOZ_RELEASE_ASSERT(accEditableSupport);
+
+    // Tell PuppetWidget to use our listener for IME operations.
+    widget->SetNativeTextEventDispatcherListener(
+        accEditableSupport.AsRefPtr().get());
+
+    accEditableSupport->mEditableAttached = true;
+
+    // Connect the new child to a parent that corresponds to the BrowserChild.
+    java::GeckoServiceChildProcess::GetEditableParent(editableChild, contentId,
+                                                      tabId);
+    return;
+  }
+
+  // We need to update the existing listener to use the new parent.
+
+  // We expect the existing TextEventDispatcherListener to be a
+  // GeckoEditableSupport object, so we perform a sanity check to make
+  // sure, by comparing their respective vtable pointers.
+  const RefPtr<widget::GeckoEditableSupport> dummy =
+      new widget::GeckoEditableSupport(/* child */ nullptr);
+  NS_ENSURE_TRUE_VOID(*reinterpret_cast<const uintptr_t*>(listener.get()) ==
+                      *reinterpret_cast<const uintptr_t*>(dummy.get()));
+
+  const auto support =
+      static_cast<widget::GeckoEditableSupport*>(listener.get());
+  if (!support->mEditableAttached) {
+    // Temporarily attach so we can receive the initial editable parent.
+    jni::NativeWeakPtrHolder<GeckoEditableSupport>::AttachExisting(
+        support->GetJavaEditable(), do_AddRef(support));
+    support->mEditableAttached = true;
+  }
+
+  // Transfer to a new parent that corresponds to the BrowserChild.
+  java::GeckoServiceChildProcess::GetEditableParent(support->GetJavaEditable(),
+                                                    contentId, tabId);
+}
+
+nsIWidget* GeckoEditableSupport::GetWidget() const {
+  MOZ_ASSERT(NS_IsMainThread());
+  return mDispatcher ? mDispatcher->GetWidget() : GetNsWindow();
+}
+
+nsWindow* GeckoEditableSupport::GetNsWindow() const {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  auto acc(mWindow.Access());
+  if (!acc) {
+    return nullptr;
+  }
+
+  return acc->GetNsWindow();
+}
+
+void GeckoEditableSupport::OnImeInsertImage(jni::ByteArray::Param aData,
+                                            jni::String::Param aMimeType) {
+  AutoGeckoEditableBlocker blocker(this);
+
+  nsCString mimeType(aMimeType->ToCString());
+  nsCOMPtr<nsIInputStream> byteStream;
+
+  nsresult rv = NS_NewByteInputStream(
+      getter_AddRefs(byteStream),
+      mozilla::Span(
+          reinterpret_cast<const char*>(aData->GetElements().Elements()),
+          aData->Length()),
+      NS_ASSIGNMENT_COPY);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return;
+  }
+
+  nsCOMPtr<nsITransferable> trans =
+      do_CreateInstance("@mozilla.org/widget/transferable;1");
+  if (NS_WARN_IF(!trans)) {
+    return;
+  }
+  trans->Init(nullptr);
+  rv = trans->SetTransferData(mimeType.get(), byteStream);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return;
+  }
+
+  nsCOMPtr<nsIWidget> widget = GetWidget();
+  if (NS_WARN_IF(!widget) || NS_WARN_IF(widget->Destroyed())) {
+    return;
+  }
+
+  WidgetContentCommandEvent command(true, eContentCommandPasteTransferable,
+                                    widget);
+  command.mTransferable = trans.forget();
+  nsEventStatus status;
+  widget->DispatchEvent(&command, status);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/GeckoEditableSupport.h b/widget/android/GeckoEditableSupport.h
new file mode 100644
index 0000000000..90cb2710d3
--- /dev/null
+++ b/widget/android/GeckoEditableSupport.h
@@ -0,0 +1,286 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_GeckoEditableSupport_h
+#define mozilla_widget_GeckoEditableSupport_h
+
+#include "nsAppShell.h"
+#include "nsIWidget.h"
+#include "nsTArray.h"
+
+#include "mozilla/java/GeckoEditableChildNatives.h"
+#include "mozilla/java/SessionTextInputWrappers.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEventDispatcherListener.h"
+#include "mozilla/UniquePtr.h"
+
+class nsWindow;
+
+namespace mozilla {
+
+class TextComposition;
+
+namespace dom {
+class BrowserChild;
+}
+
+namespace widget {
+
+class GeckoEditableSupport final
+    : public TextEventDispatcherListener,
+      public java::GeckoEditableChild::Natives<GeckoEditableSupport> {
+  /*
+      Rules for managing IME between Gecko and Java:
+
+      * Gecko controls the text content, and Java shadows the Gecko text
+         through text updates
+      * Gecko and Java maintain separate selections, and synchronize when
+         needed through selection updates and set-selection events
+      * Java controls the composition, and Gecko shadows the Java
+         composition through update composition events
+  */
+
+  using EditableBase = java::GeckoEditableChild::Natives<GeckoEditableSupport>;
+  using EditableClient = java::SessionTextInput::EditableClient;
+  using EditableListener = java::SessionTextInput::EditableListener;
+
+  enum FlushChangesFlag {
+    // Not retrying.
+    FLUSH_FLAG_NONE,
+    // Retrying due to IME text changes during flush.
+    FLUSH_FLAG_RETRY,
+    // Retrying due to IME sync exceptions during flush.
+    FLUSH_FLAG_RECOVER
+  };
+
+  enum RemoveCompositionFlag { CANCEL_IME_COMPOSITION, COMMIT_IME_COMPOSITION };
+
+  const bool mIsRemote;
+  jni::NativeWeakPtr<GeckoViewSupport> mWindow;  // Parent only
+  RefPtr<TextEventDispatcher> mDispatcher;
+  java::GeckoEditableChild::GlobalRef mEditable;
+  bool mEditableAttached;
+  InputContext mInputContext;
+  AutoTArray<UniquePtr<mozilla::WidgetEvent>, 4> mIMEKeyEvents;
+  IMENotification::TextChangeData mIMEPendingTextChange;
+  RefPtr<TextRangeArray> mIMERanges;
+  RefPtr<Runnable> mDisposeRunnable;
+  int32_t mIMEMaskEventsCount;         // Mask events when > 0.
+  int32_t mIMEFocusCount;              // We are focused when > 0.
+  bool mIMEDelaySynchronizeReply;      // We reply asynchronously when true.
+  int32_t mIMEActiveSynchronizeCount;  // The number of replies being delayed.
+  int32_t mIMEActiveCompositionCount;  // The number of compositions expected.
+  uint32_t mDisposeBlockCount;
+  bool mIMESelectionChanged;
+  bool mIMETextChangedDuringFlush;
+  bool mIMEMonitorCursor;
+
+  // The cached selection data
+  struct Selection {
+    Selection() : mStartOffset(-1), mEndOffset(-1) {}
+
+    void Reset() {
+      mStartOffset = -1;
+      mEndOffset = -1;
+    }
+
+    bool IsValid() const { return mStartOffset >= 0 && mEndOffset >= 0; }
+
+    int32_t mStartOffset;
+    int32_t mEndOffset;
+  } mCachedSelection;
+
+  nsIWidget* GetWidget() const;
+  nsWindow* GetNsWindow() const;
+
+  nsresult BeginInputTransaction(TextEventDispatcher* aDispatcher) {
+    if (mIsRemote) {
+      return aDispatcher->BeginInputTransaction(this);
+    } else {
+      return aDispatcher->BeginNativeInputTransaction();
+    }
+  }
+
+  virtual ~GeckoEditableSupport() {}
+
+  RefPtr<TextComposition> GetComposition() const;
+  bool RemoveComposition(RemoveCompositionFlag aFlag = COMMIT_IME_COMPOSITION);
+  void SendIMEDummyKeyEvent(nsIWidget* aWidget, EventMessage msg);
+  void AddIMETextChange(const IMENotification::TextChangeDataBase& aChange);
+  void PostFlushIMEChanges();
+  void FlushIMEChanges(FlushChangesFlag aFlags = FLUSH_FLAG_NONE);
+  void FlushIMEText(FlushChangesFlag aFlags = FLUSH_FLAG_NONE);
+  void AsyncNotifyIME(int32_t aNotification);
+  void UpdateCompositionRects();
+  bool DoReplaceText(int32_t aStart, int32_t aEnd, jni::String::Param aText);
+  bool DoUpdateComposition(int32_t aStart, int32_t aEnd, int32_t aFlags);
+  void OnNotifyIMEOfCompositionEventHandled();
+  void NotifyIMEContext(const InputContext& aContext,
+                        const InputContextAction& aAction);
+
+ public:
+  template <typename Functor>
+  static void OnNativeCall(Functor&& aCall) {
+    struct IMEEvent : nsAppShell::LambdaEvent<Functor> {
+      explicit IMEEvent(Functor&& l)
+          : nsAppShell::LambdaEvent<Functor>(std::move(l)) {}
+
+      bool IsUIEvent() const override {
+        using GES = GeckoEditableSupport;
+        if (this->lambda.IsTarget(&GES::OnKeyEvent) ||
+            this->lambda.IsTarget(&GES::OnImeReplaceText) ||
+            this->lambda.IsTarget(&GES::OnImeUpdateComposition)) {
+          return true;
+        }
+        return false;
+      }
+
+      void Run() override {
+        if (NS_WARN_IF(!this->lambda.GetNativeObject())) {
+          // Ignore stale calls after disposal.
+          jni::GetGeckoThreadEnv()->ExceptionClear();
+          return;
+        }
+        nsAppShell::LambdaEvent<Functor>::Run();
+      }
+    };
+    nsAppShell::PostEvent(mozilla::MakeUnique<IMEEvent>(std::move(aCall)));
+  }
+
+  static void SetOnBrowserChild(dom::BrowserChild* aBrowserChild);
+
+  // Constructor for main process GeckoEditableChild.
+  GeckoEditableSupport(jni::NativeWeakPtr<GeckoViewSupport> aWindow,
+                       java::GeckoEditableChild::Param aEditableChild)
+      : mIsRemote(!aWindow.IsAttached()),
+        mWindow(aWindow),
+        mEditable(aEditableChild),
+        mEditableAttached(!mIsRemote),
+        mIMERanges(new TextRangeArray()),
+        mIMEMaskEventsCount(1),  // Mask IME events since there's no focus yet
+        mIMEFocusCount(0),
+        mIMEDelaySynchronizeReply(false),
+        mIMEActiveSynchronizeCount(0),
+        mDisposeBlockCount(0),
+        mIMESelectionChanged(false),
+        mIMETextChangedDuringFlush(false),
+        mIMEMonitorCursor(false) {}
+
+  // Constructor for content process GeckoEditableChild.
+  explicit GeckoEditableSupport(java::GeckoEditableChild::Param aEditableChild)
+      : GeckoEditableSupport(nullptr, aEditableChild) {}
+
+  NS_DECL_ISUPPORTS
+
+  // TextEventDispatcherListener methods
+  NS_IMETHOD NotifyIME(TextEventDispatcher* aTextEventDispatcher,
+                       const IMENotification& aNotification) override;
+
+  NS_IMETHOD_(IMENotificationRequests) GetIMENotificationRequests() override;
+
+  NS_IMETHOD_(void)
+  OnRemovedFrom(TextEventDispatcher* aTextEventDispatcher) override;
+
+  NS_IMETHOD_(void)
+  WillDispatchKeyboardEvent(TextEventDispatcher* aTextEventDispatcher,
+                            WidgetKeyboardEvent& aKeyboardEvent,
+                            uint32_t aIndexOfKeypress, void* aData) override;
+
+  void SetInputContext(const InputContext& aContext,
+                       const InputContextAction& aAction);
+
+  InputContext GetInputContext();
+
+  bool HasIMEFocus() const { return mIMEFocusCount != 0; }
+
+  void AddBlocker() { mDisposeBlockCount++; }
+
+  void ReleaseBlocker() {
+    mDisposeBlockCount--;
+
+    if (!mDisposeBlockCount && mDisposeRunnable) {
+      if (HasIMEFocus()) {
+        // If we have IME focus, GeckoEditableChild is already attached again.
+        // So disposer is unnecessary.
+        mDisposeRunnable = nullptr;
+        return;
+      }
+
+      RefPtr<GeckoEditableSupport> self(this);
+      RefPtr<Runnable> disposer = std::move(mDisposeRunnable);
+
+      nsAppShell::PostEvent(
+          [self = std::move(self), disposer = std::move(disposer)] {
+            self->mEditableAttached = false;
+            disposer->Run();
+          });
+    }
+  }
+
+  bool IsGeckoEditableUsed() const { return mDisposeBlockCount != 0; }
+
+  // GeckoEditableChild methods
+  using EditableBase::AttachNative;
+  using EditableBase::DisposeNative;
+
+  const java::GeckoEditableChild::Ref& GetJavaEditable() { return mEditable; }
+
+  void OnWeakNonIntrusiveDetach(already_AddRefed<Runnable> aDisposer) {
+    RefPtr<GeckoEditableSupport> self(this);
+    nsAppShell::PostEvent(
+        [self = std::move(self), disposer = RefPtr<Runnable>(aDisposer)] {
+          if (self->IsGeckoEditableUsed()) {
+            // Current calling stack uses GeckoEditableChild, so we should
+            // not dispose it now.
+            self->mDisposeRunnable = disposer;
+            return;
+          }
+          self->mEditableAttached = false;
+          disposer->Run();
+        });
+  }
+
+  // Transfer to a new parent.
+  void TransferParent(jni::Object::Param aEditableParent);
+
+  // Handle an Android KeyEvent.
+  void OnKeyEvent(int32_t aAction, int32_t aKeyCode, int32_t aScanCode,
+                  int32_t aMetaState, int32_t aKeyPressMetaState, int64_t aTime,
+                  int32_t aDomPrintableKeyValue, int32_t aRepeatCount,
+                  int32_t aFlags, bool aIsSynthesizedImeKey,
+                  jni::Object::Param originalEvent);
+
+  // Synchronize Gecko thread with the InputConnection thread.
+  void OnImeSynchronize();
+
+  // Replace a range of text with new text.
+  void OnImeReplaceText(int32_t aStart, int32_t aEnd, jni::String::Param aText);
+
+  // Add styling for a range within the active composition.
+  void OnImeAddCompositionRange(int32_t aStart, int32_t aEnd,
+                                int32_t aRangeType, int32_t aRangeStyle,
+                                int32_t aRangeLineStyle, bool aRangeBoldLine,
+                                int32_t aRangeForeColor,
+                                int32_t aRangeBackColor,
+                                int32_t aRangeLineColor);
+
+  // Update styling for the active composition using previous-added ranges.
+  void OnImeUpdateComposition(int32_t aStart, int32_t aEnd, int32_t aFlags);
+
+  // Set cursor mode whether IME requests
+  void OnImeRequestCursorUpdates(int aRequestMode);
+
+  // Commit current composition to sync Gecko text state with Java.
+  void OnImeRequestCommit();
+
+  // Insert image from software keyboard.
+  void OnImeInsertImage(jni::ByteArray::Param aData,
+                        jni::String::Param aMimeType);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_GeckoEditableSupport_h
diff --git a/widget/android/GeckoNetworkManager.h b/widget/android/GeckoNetworkManager.h
new file mode 100644
index 0000000000..7240821b9e
--- /dev/null
+++ b/widget/android/GeckoNetworkManager.h
@@ -0,0 +1,45 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GeckoNetworkManager_h
+#define GeckoNetworkManager_h
+
+#include "nsAppShell.h"
+#include "nsCOMPtr.h"
+#include "nsINetworkLinkService.h"
+
+#include "mozilla/java/GeckoNetworkManagerNatives.h"
+#include "mozilla/Services.h"
+
+namespace mozilla {
+
+class GeckoNetworkManager final
+    : public java::GeckoNetworkManager::Natives<GeckoNetworkManager> {
+  GeckoNetworkManager() = delete;
+
+ public:
+  static void OnConnectionChanged(int32_t aType, jni::String::Param aSubType,
+                                  bool aIsWifi, int32_t aGateway) {
+    hal::NotifyNetworkChange(hal::NetworkInformation(aType, aIsWifi, aGateway));
+
+    nsCOMPtr<nsIObserverService> os = services::GetObserverService();
+    if (os) {
+      os->NotifyObservers(nullptr, NS_NETWORK_LINK_TYPE_TOPIC,
+                          aSubType->ToString().get());
+    }
+  }
+
+  static void OnStatusChanged(jni::String::Param aStatus) {
+    nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+    if (os) {
+      os->NotifyObservers(nullptr, NS_NETWORK_LINK_TOPIC,
+                          aStatus->ToString().get());
+    }
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // GeckoNetworkManager_h
diff --git a/widget/android/GeckoProcessManager.cpp b/widget/android/GeckoProcessManager.cpp
new file mode 100644
index 0000000000..274e92ed9b
--- /dev/null
+++ b/widget/android/GeckoProcessManager.cpp
@@ -0,0 +1,77 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GeckoProcessManager.h"
+
+#include "nsINetworkLinkService.h"
+#include "nsISupportsImpl.h"
+#include "mozilla/Services.h"
+
+namespace mozilla {
+
+/* static */ void GeckoProcessManager::Init() {
+  BaseNatives::Init();
+  ConnectionManager::Init();
+}
+
+NS_IMPL_ISUPPORTS(GeckoProcessManager::ConnectionManager, nsIObserver)
+
+NS_IMETHODIMP GeckoProcessManager::ConnectionManager::Observe(
+    nsISupports* aSubject, const char* aTopic, const char16_t* aData) {
+  java::GeckoProcessManager::ConnectionManager::LocalRef connMgr(mJavaConnMgr);
+  if (!connMgr) {
+    return NS_OK;
+  }
+
+  if (!strcmp("application-foreground", aTopic)) {
+    connMgr->OnForeground();
+    return NS_OK;
+  }
+
+  if (!strcmp("application-background", aTopic)) {
+    connMgr->OnBackground();
+    return NS_OK;
+  }
+
+  if (!strcmp(NS_NETWORK_LINK_TOPIC, aTopic)) {
+    const nsDependentString state(aData);
+    // state can be up, down, or unknown. For the purposes of socket process
+    // prioritization, we treat unknown as being up.
+    const bool isUp = !state.EqualsLiteral(NS_NETWORK_LINK_DATA_DOWN);
+    connMgr->OnNetworkStateChange(isUp);
+    return NS_OK;
+  }
+
+  return NS_OK;
+}
+
+/* static */ void GeckoProcessManager::ConnectionManager::AttachTo(
+    java::GeckoProcessManager::ConnectionManager::Param aInstance) {
+  RefPtr<ConnectionManager> native(new ConnectionManager());
+  BaseNatives::AttachNative(aInstance, native);
+
+  native->mJavaConnMgr = aInstance;
+
+  nsCOMPtr<nsIObserverService> obsServ(services::GetObserverService());
+  obsServ->AddObserver(native, "application-background", false);
+  obsServ->AddObserver(native, "application-foreground", false);
+}
+
+void GeckoProcessManager::ConnectionManager::ObserveNetworkNotifications() {
+  nsCOMPtr<nsIObserverService> obsServ(services::GetObserverService());
+  obsServ->AddObserver(this, NS_NETWORK_LINK_TOPIC, false);
+
+  const bool isUp = java::GeckoAppShell::IsNetworkLinkUp();
+
+  java::GeckoProcessManager::ConnectionManager::LocalRef connMgr(mJavaConnMgr);
+  if (!connMgr) {
+    return;
+  }
+
+  connMgr->OnNetworkStateChange(isUp);
+}
+
+}  // namespace mozilla
diff --git a/widget/android/GeckoProcessManager.h b/widget/android/GeckoProcessManager.h
new file mode 100644
index 0000000000..341cb5f5c5
--- /dev/null
+++ b/widget/android/GeckoProcessManager.h
@@ -0,0 +1,84 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GeckoProcessManager_h
+#define GeckoProcessManager_h
+
+#include "WidgetUtils.h"
+#include "nsAppShell.h"
+#include "nsContentUtils.h"
+#include "nsIObserver.h"
+#include "nsWindow.h"
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/dom/BrowserParent.h"
+#include "mozilla/dom/ContentProcessManager.h"
+#include "mozilla/java/GeckoProcessManagerNatives.h"
+
+namespace mozilla {
+
+class GeckoProcessManager final
+    : public java::GeckoProcessManager::Natives<GeckoProcessManager> {
+  using BaseNatives = java::GeckoProcessManager::Natives<GeckoProcessManager>;
+
+  GeckoProcessManager() = delete;
+
+  static already_AddRefed<nsIWidget> GetWidget(int64_t aContentId,
+                                               int64_t aTabId) {
+    using namespace dom;
+    MOZ_ASSERT(NS_IsMainThread());
+
+    ContentProcessManager* const cpm = ContentProcessManager::GetSingleton();
+    NS_ENSURE_TRUE(cpm, nullptr);
+
+    RefPtr<BrowserParent> tab = cpm->GetTopLevelBrowserParentByProcessAndTabId(
+        ContentParentId(aContentId), TabId(aTabId));
+    NS_ENSURE_TRUE(tab, nullptr);
+
+    nsCOMPtr<nsPIDOMWindowOuter> domWin = tab->GetParentWindowOuter();
+    NS_ENSURE_TRUE(domWin, nullptr);
+
+    return widget::WidgetUtils::DOMWindowToWidget(domWin);
+  }
+
+  class ConnectionManager final
+      : public java::GeckoProcessManager::ConnectionManager::Natives<
+            ConnectionManager>,
+        public nsIObserver {
+    using BaseNatives = java::GeckoProcessManager::ConnectionManager::Natives<
+        ConnectionManager>;
+
+    virtual ~ConnectionManager() = default;
+
+   public:
+    ConnectionManager() = default;
+
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIOBSERVER
+
+    static void AttachTo(
+        java::GeckoProcessManager::ConnectionManager::Param aInstance);
+    void ObserveNetworkNotifications();
+
+   private:
+    java::GeckoProcessManager::ConnectionManager::WeakRef mJavaConnMgr;
+  };
+
+ public:
+  static void Init();
+
+  static void GetEditableParent(jni::Object::Param aEditableChild,
+                                int64_t aContentId, int64_t aTabId) {
+    nsCOMPtr<nsIWidget> widget = GetWidget(aContentId, aTabId);
+    if (RefPtr<nsWindow> window = nsWindow::From(widget)) {
+      java::GeckoProcessManager::SetEditableChildParent(
+          aEditableChild, window->GetEditableParent());
+    }
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // GeckoProcessManager_h
diff --git a/widget/android/GeckoSystemStateListener.h b/widget/android/GeckoSystemStateListener.h
new file mode 100644
index 0000000000..75cb1cd9fe
--- /dev/null
+++ b/widget/android/GeckoSystemStateListener.h
@@ -0,0 +1,31 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GeckoSystemStateListener_h
+#define GeckoSystemStateListener_h
+
+#include "mozilla/Assertions.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/java/GeckoSystemStateListenerNatives.h"
+
+namespace mozilla {
+
+class GeckoSystemStateListener final
+    : public java::GeckoSystemStateListener::Natives<GeckoSystemStateListener> {
+  GeckoSystemStateListener() = delete;
+
+ public:
+  static void OnDeviceChanged() {
+    MOZ_ASSERT(NS_IsMainThread());
+    // TODO(emilio, bug 1673318): This could become more granular and avoid work
+    // if we get whether these are layout/style-affecting from the caller.
+    mozilla::LookAndFeel::NotifyChangedAllWindows(
+        widget::ThemeChangeKind::StyleAndLayout);
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // GeckoSystemStateListener_h
diff --git a/widget/android/GeckoTelemetryDelegate.h b/widget/android/GeckoTelemetryDelegate.h
new file mode 100644
index 0000000000..43b20d4ad6
--- /dev/null
+++ b/widget/android/GeckoTelemetryDelegate.h
@@ -0,0 +1,100 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GeckoTelemetryDelegate_h__
+#define GeckoTelemetryDelegate_h__
+
+#include "geckoview/streaming/GeckoViewStreamingTelemetry.h"
+
+#include <jni.h>
+
+#include "mozilla/java/RuntimeTelemetryNatives.h"
+#include "mozilla/jni/Natives.h"
+
+namespace mozilla {
+namespace widget {
+
+class GeckoTelemetryDelegate final
+    : public GeckoViewStreamingTelemetry::StreamingTelemetryDelegate,
+      public mozilla::java::RuntimeTelemetry::Proxy::Natives<
+          GeckoTelemetryDelegate> {
+ public:
+  // Implement Proxy native.
+  static void RegisterDelegateProxy(
+      mozilla::java::RuntimeTelemetry::Proxy::Param aProxy) {
+    MOZ_ASSERT(aProxy);
+
+    GeckoViewStreamingTelemetry::RegisterDelegate(
+        new GeckoTelemetryDelegate(aProxy));
+  }
+
+  explicit GeckoTelemetryDelegate(
+      mozilla::java::RuntimeTelemetry::Proxy::Param aProxy)
+      : mProxy(aProxy) {}
+
+ private:
+  void DispatchHistogram(bool aIsCategorical, const nsCString& aName,
+                         const nsTArray<uint32_t>& aSamples) {
+    if (!mozilla::jni::IsAvailable() || !mProxy || aSamples.Length() < 1) {
+      return;
+    }
+
+    // Convert aSamples to an array of int64_t. We know |samples| required
+    // capacity needs to match |aSamples.Length()|.
+    nsTArray<int64_t> samples(aSamples.Length());
+    for (size_t i = 0, l = aSamples.Length(); i < l; ++i) {
+      samples.AppendElement(static_cast<int64_t>(aSamples[i]));
+    }
+
+    // LongArray::From *copies* the elements
+    mProxy->DispatchHistogram(aIsCategorical, aName,
+                              mozilla::jni::LongArray::From(samples));
+  }
+
+  // Implement StreamingTelemetryDelegate.
+  void ReceiveHistogramSamples(const nsCString& aName,
+                               const nsTArray<uint32_t>& aSamples) override {
+    DispatchHistogram(/* isCategorical */ false, aName, aSamples);
+  }
+
+  void ReceiveCategoricalHistogramSamples(
+      const nsCString& aName, const nsTArray<uint32_t>& aSamples) override {
+    DispatchHistogram(/* isCategorical */ true, aName, aSamples);
+  }
+
+  void ReceiveBoolScalarValue(const nsCString& aName, bool aValue) override {
+    if (!mozilla::jni::IsAvailable() || !mProxy) {
+      return;
+    }
+
+    mProxy->DispatchBooleanScalar(aName, aValue);
+  }
+
+  void ReceiveStringScalarValue(const nsCString& aName,
+                                const nsCString& aValue) override {
+    if (!mozilla::jni::IsAvailable() || !mProxy) {
+      return;
+    }
+
+    mProxy->DispatchStringScalar(aName, aValue);
+  }
+
+  void ReceiveUintScalarValue(const nsCString& aName,
+                              uint32_t aValue) override {
+    if (!mozilla::jni::IsAvailable() || !mProxy) {
+      return;
+    }
+
+    mProxy->DispatchLongScalar(aName, static_cast<int64_t>(aValue));
+  }
+
+  mozilla::java::RuntimeTelemetry::Proxy::GlobalRef mProxy;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // GeckoTelemetryDelegate_h__
diff --git a/widget/android/GeckoVRManager.h b/widget/android/GeckoVRManager.h
new file mode 100644
index 0000000000..de28c402cd
--- /dev/null
+++ b/widget/android/GeckoVRManager.h
@@ -0,0 +1,24 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_GeckoVRManager_h_
+#define mozilla_GeckoVRManager_h_
+
+#include "mozilla/java/GeckoVRManagerWrappers.h"
+#include "mozilla/jni/Utils.h"
+
+namespace mozilla {
+
+class GeckoVRManager {
+ public:
+  static void* GetExternalContext() {
+    return reinterpret_cast<void*>(
+        mozilla::java::GeckoVRManager::GetExternalContext());
+  }
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_GeckoVRManager_h_
diff --git a/widget/android/GeckoViewSupport.h b/widget/android/GeckoViewSupport.h
new file mode 100644
index 0000000000..c784552824
--- /dev/null
+++ b/widget/android/GeckoViewSupport.h
@@ -0,0 +1,126 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_GeckoViewSupport_h
+#define mozilla_widget_GeckoViewSupport_h
+
+#include "mozilla/java/GeckoResultWrappers.h"
+#include "mozilla/java/GeckoSessionNatives.h"
+#include "mozilla/java/WebResponseWrappers.h"
+#include "mozilla/dom/CanonicalBrowsingContext.h"
+#include "mozilla/widget/WindowEvent.h"
+
+class nsPIDOMWindowOuter;
+class nsWindow;
+
+namespace mozilla {
+namespace widget {
+
+class GeckoViewSupport final
+    : public java::GeckoSession::Window::Natives<GeckoViewSupport> {
+  RefPtr<nsWindow> mWindow;
+
+  // We hold a WeakRef because we want to allow the
+  // GeckoSession.Window to be garbage collected.
+  // Callers need to create a LocalRef from this
+  // before calling methods.
+  java::GeckoSession::Window::WeakRef mGeckoViewWindow;
+
+ public:
+  typedef java::GeckoSession::Window::Natives<GeckoViewSupport> Base;
+
+  template <typename Functor>
+  static void OnNativeCall(Functor&& aCall) {
+    NS_DispatchToMainThread(new WindowEvent<Functor>(std::move(aCall)));
+  }
+
+  GeckoViewSupport(nsWindow* aWindow,
+                   const java::GeckoSession::Window::LocalRef& aInstance,
+                   nsPIDOMWindowOuter* aDOMWindow)
+      : mWindow(aWindow), mGeckoViewWindow(aInstance), mDOMWindow(aDOMWindow) {}
+
+  ~GeckoViewSupport();
+
+  nsWindow* GetNsWindow() const { return mWindow; }
+
+  using Base::DisposeNative;
+
+  /**
+   * GeckoView methods
+   */
+ private:
+  nsCOMPtr<nsPIDOMWindowOuter> mDOMWindow;
+  bool mIsReady{false};
+  RefPtr<dom::CanonicalBrowsingContext> GetContentCanonicalBrowsingContext();
+  MOZ_CAN_RUN_SCRIPT void CreatePdf(
+      jni::LocalRef<mozilla::java::GeckoResult> aGeckoResult,
+      RefPtr<dom::CanonicalBrowsingContext> aCbc);
+
+ public:
+  // Create and attach a window.
+  static void Open(const jni::Class::LocalRef& aCls,
+                   java::GeckoSession::Window::Param aWindow,
+                   jni::Object::Param aQueue, jni::Object::Param aCompositor,
+                   jni::Object::Param aDispatcher,
+                   jni::Object::Param aSessionAccessibility,
+                   jni::Object::Param aInitData, jni::String::Param aId,
+                   jni::String::Param aChromeURI, bool aPrivateMode);
+
+  // Close and destroy the nsWindow.
+  void Close();
+
+  // Transfer this nsWindow to new GeckoSession objects.
+  void Transfer(const java::GeckoSession::Window::LocalRef& inst,
+                jni::Object::Param aQueue, jni::Object::Param aCompositor,
+                jni::Object::Param aDispatcher,
+                jni::Object::Param aSessionAccessibility,
+                jni::Object::Param aInitData);
+
+  void AttachEditable(const java::GeckoSession::Window::LocalRef& inst,
+                      jni::Object::Param aEditableParent);
+
+  void AttachAccessibility(const java::GeckoSession::Window::LocalRef& inst,
+                           jni::Object::Param aSessionAccessibility);
+
+  void OnReady(jni::Object::Param aQueue = nullptr);
+
+  auto OnLoadRequest(mozilla::jni::String::Param aUri, int32_t aWindowType,
+                     int32_t aFlags, mozilla::jni::String::Param aTriggeringUri,
+                     bool aHasUserGesture, bool aIsTopLevel) const
+      -> java::GeckoResult::LocalRef;
+
+  void OnShowDynamicToolbar() const;
+
+  void OnUpdateSessionStore(mozilla::jni::Object::Param aBundle);
+
+  void PassExternalResponse(java::WebResponse::Param aResponse);
+
+  void AttachMediaSessionController(
+      const java::GeckoSession::Window::LocalRef& inst,
+      jni::Object::Param aController, const int64_t aId);
+
+  void DetachMediaSessionController(
+      const java::GeckoSession::Window::LocalRef& inst,
+      jni::Object::Param aController);
+
+  void OnWeakNonIntrusiveDetach(already_AddRefed<Runnable> aDisposer) {
+    RefPtr<Runnable> disposer(aDisposer);
+    disposer->Run();
+  }
+
+  MOZ_CAN_RUN_SCRIPT void PrintToPdf(
+      const java::GeckoSession::Window::LocalRef& inst,
+      jni::Object::Param aStream, int64_t aBcId);
+
+  MOZ_CAN_RUN_SCRIPT void PrintToPdf(
+      const java::GeckoSession::Window::LocalRef& inst,
+      jni::Object::Param aStream);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_GeckoViewSupport_h
diff --git a/widget/android/GfxInfo.cpp b/widget/android/GfxInfo.cpp
new file mode 100644
index 0000000000..0e78b187bf
--- /dev/null
+++ b/widget/android/GfxInfo.cpp
@@ -0,0 +1,856 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GfxInfo.h"
+#include "AndroidBuild.h"
+#include "GLContext.h"
+#include "GLContextProvider.h"
+#include "nsUnicharUtils.h"
+#include "prenv.h"
+#include "nsExceptionHandler.h"
+#include "nsHashKeys.h"
+#include "nsVersionComparator.h"
+#include "nsServiceManagerUtils.h"
+
+#include "mozilla/Preferences.h"
+#include "mozilla/java/GeckoAppShellWrappers.h"
+#include "mozilla/java/HardwareCodecCapabilityUtilsWrappers.h"
+
+namespace mozilla {
+namespace widget {
+
+class GfxInfo::GLStrings {
+  nsCString mVendor;
+  nsCString mRenderer;
+  nsCString mVersion;
+  nsTArray<nsCString> mExtensions;
+  bool mReady;
+
+ public:
+  GLStrings() : mReady(false) {}
+
+  const nsCString& Vendor() {
+    EnsureInitialized();
+    return mVendor;
+  }
+
+  // This spoofed value wins, even if the environment variable
+  // MOZ_GFX_SPOOF_GL_VENDOR was set.
+  void SpoofVendor(const nsCString& s) { mVendor = s; }
+
+  const nsCString& Renderer() {
+    EnsureInitialized();
+    return mRenderer;
+  }
+
+  // This spoofed value wins, even if the environment variable
+  // MOZ_GFX_SPOOF_GL_RENDERER was set.
+  void SpoofRenderer(const nsCString& s) { mRenderer = s; }
+
+  const nsCString& Version() {
+    EnsureInitialized();
+    return mVersion;
+  }
+
+  // This spoofed value wins, even if the environment variable
+  // MOZ_GFX_SPOOF_GL_VERSION was set.
+  void SpoofVersion(const nsCString& s) { mVersion = s; }
+
+  const nsTArray<nsCString>& Extensions() {
+    EnsureInitialized();
+    return mExtensions;
+  }
+
+  void EnsureInitialized() {
+    if (mReady) {
+      return;
+    }
+
+    RefPtr<gl::GLContext> gl;
+    nsCString discardFailureId;
+    gl = gl::GLContextProvider::CreateHeadless(
+        {gl::CreateContextFlags::REQUIRE_COMPAT_PROFILE}, &discardFailureId);
+
+    if (!gl) {
+      // Setting mReady to true here means that we won't retry. Everything will
+      // remain blocklisted forever. Ideally, we would like to update that once
+      // any GLContext is successfully created, like the compositor's GLContext.
+      mReady = true;
+      return;
+    }
+
+    gl->MakeCurrent();
+
+    if (mVendor.IsEmpty()) {
+      const char* spoofedVendor = PR_GetEnv("MOZ_GFX_SPOOF_GL_VENDOR");
+      if (spoofedVendor) {
+        mVendor.Assign(spoofedVendor);
+      } else {
+        mVendor.Assign((const char*)gl->fGetString(LOCAL_GL_VENDOR));
+      }
+    }
+
+    if (mRenderer.IsEmpty()) {
+      const char* spoofedRenderer = PR_GetEnv("MOZ_GFX_SPOOF_GL_RENDERER");
+      if (spoofedRenderer) {
+        mRenderer.Assign(spoofedRenderer);
+      } else {
+        mRenderer.Assign((const char*)gl->fGetString(LOCAL_GL_RENDERER));
+      }
+    }
+
+    if (mVersion.IsEmpty()) {
+      const char* spoofedVersion = PR_GetEnv("MOZ_GFX_SPOOF_GL_VERSION");
+      if (spoofedVersion) {
+        mVersion.Assign(spoofedVersion);
+      } else {
+        mVersion.Assign((const char*)gl->fGetString(LOCAL_GL_VERSION));
+      }
+    }
+
+    if (mExtensions.IsEmpty()) {
+      nsCString rawExtensions;
+      rawExtensions.Assign((const char*)gl->fGetString(LOCAL_GL_EXTENSIONS));
+      rawExtensions.Trim(" ");
+
+      for (auto extension : rawExtensions.Split(' ')) {
+        mExtensions.AppendElement(extension);
+      }
+    }
+
+    mReady = true;
+  }
+};
+
+#ifdef DEBUG
+NS_IMPL_ISUPPORTS_INHERITED(GfxInfo, GfxInfoBase, nsIGfxInfoDebug)
+#endif
+
+GfxInfo::GfxInfo()
+    : mInitialized(false),
+      mGLStrings(new GLStrings),
+      mOSVersionInteger(0),
+      mSDKVersion(0) {}
+
+GfxInfo::~GfxInfo() {}
+
+/* GetD2DEnabled and GetDwriteEnabled shouldn't be called until after
+ * gfxPlatform initialization has occurred because they depend on it for
+ * information. (See bug 591561) */
+nsresult GfxInfo::GetD2DEnabled(bool* aEnabled) { return NS_ERROR_FAILURE; }
+
+nsresult GfxInfo::GetDWriteEnabled(bool* aEnabled) { return NS_ERROR_FAILURE; }
+
+nsresult GfxInfo::GetHasBattery(bool* aHasBattery) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetDWriteVersion(nsAString& aDwriteVersion) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetEmbeddedInFirefoxReality(bool* aEmbeddedInFirefoxReality) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetCleartypeParameters(nsAString& aCleartypeParams) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetWindowProtocol(nsAString& aWindowProtocol) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetTestType(nsAString& aTestType) { return NS_ERROR_NOT_IMPLEMENTED; }
+
+void GfxInfo::EnsureInitialized() {
+  if (mInitialized) return;
+
+  if (!jni::IsAvailable()) {
+    gfxWarning() << "JNI missing during initialization";
+    return;
+  }
+
+  jni::String::LocalRef model = java::sdk::Build::MODEL();
+  mModel = model->ToString();
+  mAdapterDescription.AppendPrintf("Model: %s",
+                                   NS_LossyConvertUTF16toASCII(mModel).get());
+
+  jni::String::LocalRef product = java::sdk::Build::PRODUCT();
+  mProduct = product->ToString();
+  mAdapterDescription.AppendPrintf(", Product: %s",
+                                   NS_LossyConvertUTF16toASCII(mProduct).get());
+
+  jni::String::LocalRef manufacturer =
+      mozilla::java::sdk::Build::MANUFACTURER();
+  mManufacturer = manufacturer->ToString();
+  mAdapterDescription.AppendPrintf(
+      ", Manufacturer: %s", NS_LossyConvertUTF16toASCII(mManufacturer).get());
+
+  mSDKVersion = java::sdk::Build::VERSION::SDK_INT();
+  jni::String::LocalRef hardware = java::sdk::Build::HARDWARE();
+  mHardware = hardware->ToString();
+  mAdapterDescription.AppendPrintf(
+      ", Hardware: %s", NS_LossyConvertUTF16toASCII(mHardware).get());
+
+  jni::String::LocalRef release = java::sdk::Build::VERSION::RELEASE();
+  mOSVersion = release->ToCString();
+
+  mOSVersionInteger = 0;
+  char a[5], b[5], c[5], d[5];
+  SplitDriverVersion(mOSVersion.get(), a, b, c, d);
+  uint8_t na = atoi(a);
+  uint8_t nb = atoi(b);
+  uint8_t nc = atoi(c);
+  uint8_t nd = atoi(d);
+
+  mOSVersionInteger = (uint32_t(na) << 24) | (uint32_t(nb) << 16) |
+                      (uint32_t(nc) << 8) | uint32_t(nd);
+
+  mAdapterDescription.AppendPrintf(
+      ", OpenGL: %s -- %s -- %s", mGLStrings->Vendor().get(),
+      mGLStrings->Renderer().get(), mGLStrings->Version().get());
+
+  AddCrashReportAnnotations();
+  mInitialized = true;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDescription(nsAString& aAdapterDescription) {
+  EnsureInitialized();
+  aAdapterDescription = NS_ConvertASCIItoUTF16(mAdapterDescription);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDescription2(nsAString& aAdapterDescription) {
+  EnsureInitialized();
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterRAM(uint32_t* aAdapterRAM) {
+  EnsureInitialized();
+  *aAdapterRAM = 0;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterRAM2(uint32_t* aAdapterRAM) {
+  EnsureInitialized();
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriver(nsAString& aAdapterDriver) {
+  EnsureInitialized();
+  aAdapterDriver.Truncate();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriver2(nsAString& aAdapterDriver) {
+  EnsureInitialized();
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVendor(nsAString& aAdapterDriverVendor) {
+  EnsureInitialized();
+  aAdapterDriverVendor.Truncate();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVendor2(nsAString& aAdapterDriverVendor) {
+  EnsureInitialized();
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVersion(nsAString& aAdapterDriverVersion) {
+  EnsureInitialized();
+  aAdapterDriverVersion = NS_ConvertASCIItoUTF16(mGLStrings->Version());
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVersion2(nsAString& aAdapterDriverVersion) {
+  EnsureInitialized();
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverDate(nsAString& aAdapterDriverDate) {
+  EnsureInitialized();
+  aAdapterDriverDate.Truncate();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverDate2(nsAString& aAdapterDriverDate) {
+  EnsureInitialized();
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterVendorID(nsAString& aAdapterVendorID) {
+  EnsureInitialized();
+  aAdapterVendorID = NS_ConvertASCIItoUTF16(mGLStrings->Vendor());
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterVendorID2(nsAString& aAdapterVendorID) {
+  EnsureInitialized();
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDeviceID(nsAString& aAdapterDeviceID) {
+  EnsureInitialized();
+  aAdapterDeviceID = NS_ConvertASCIItoUTF16(mGLStrings->Renderer());
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDeviceID2(nsAString& aAdapterDeviceID) {
+  EnsureInitialized();
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterSubsysID(nsAString& aAdapterSubsysID) {
+  EnsureInitialized();
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterSubsysID2(nsAString& aAdapterSubsysID) {
+  EnsureInitialized();
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetIsGPU2Active(bool* aIsGPU2Active) {
+  EnsureInitialized();
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetDrmRenderDevice(nsACString& aDrmRenderDevice) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+void GfxInfo::AddCrashReportAnnotations() {
+  CrashReporter::AnnotateCrashReport(CrashReporter::Annotation::AdapterVendorID,
+                                     mGLStrings->Vendor());
+  CrashReporter::AnnotateCrashReport(CrashReporter::Annotation::AdapterDeviceID,
+                                     mGLStrings->Renderer());
+  CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::AdapterDriverVersion, mGLStrings->Version());
+}
+
+const nsTArray<GfxDriverInfo>& GfxInfo::GetGfxDriverInfo() {
+  if (sDriverInfo->IsEmpty()) {
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Android, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_OPENGL_LAYERS, nsIGfxInfo::FEATURE_STATUS_OK,
+        DRIVER_COMPARISON_IGNORED, GfxDriverInfo::allDriverVersions,
+        "FEATURE_OK_FORCE_OPENGL");
+  }
+
+  return *sDriverInfo;
+}
+
+nsresult GfxInfo::GetFeatureStatusImpl(
+    int32_t aFeature, int32_t* aStatus, nsAString& aSuggestedDriverVersion,
+    const nsTArray<GfxDriverInfo>& aDriverInfo, nsACString& aFailureId,
+    OperatingSystem* aOS /* = nullptr */) {
+  NS_ENSURE_ARG_POINTER(aStatus);
+  aSuggestedDriverVersion.SetIsVoid(true);
+  *aStatus = nsIGfxInfo::FEATURE_STATUS_UNKNOWN;
+  OperatingSystem os = OperatingSystem::Android;
+  if (aOS) *aOS = os;
+
+  if (sShutdownOccurred) {
+    return NS_OK;
+  }
+
+  // OpenGL layers are never blocklisted on Android.
+  // This early return is so we avoid potentially slow
+  // GLStrings initialization on startup when we initialize GL layers.
+  if (aFeature == nsIGfxInfo::FEATURE_OPENGL_LAYERS) {
+    *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+    return NS_OK;
+  }
+
+  EnsureInitialized();
+
+  if (mGLStrings->Vendor().IsEmpty() || mGLStrings->Renderer().IsEmpty()) {
+    if (OnlyAllowFeatureOnKnownConfig(aFeature)) {
+      *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+      aFailureId = "FEATURE_FAILURE_EMPTY_VENDOR_OR_RENDERER";
+    } else {
+      *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+    }
+    return NS_OK;
+  }
+
+  // Don't evaluate special cases when evaluating the downloaded blocklist.
+  if (aDriverInfo.IsEmpty()) {
+    if (aFeature == nsIGfxInfo::FEATURE_CANVAS2D_ACCELERATION) {
+      if (mGLStrings->Renderer().Find("Vivante GC1000") != -1) {
+        // Blocklist Vivante GC1000. See bug 1248183.
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILED_CANVAS_2D_HW";
+      } else {
+        *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+      }
+      return NS_OK;
+    }
+
+    if (aFeature == FEATURE_WEBGL_OPENGL) {
+      if (mGLStrings->Renderer().Find("Adreno 200") != -1 ||
+          mGLStrings->Renderer().Find("Adreno 205") != -1) {
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_ADRENO_20x";
+        return NS_OK;
+      }
+
+      if (mHardware.EqualsLiteral("ville")) {
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_VILLE";
+        return NS_OK;
+      }
+    }
+
+    if (aFeature == FEATURE_STAGEFRIGHT) {
+      NS_LossyConvertUTF16toASCII cManufacturer(mManufacturer);
+      NS_LossyConvertUTF16toASCII cModel(mModel);
+      NS_LossyConvertUTF16toASCII cHardware(mHardware);
+
+      if (cHardware.EqualsLiteral("antares") ||
+          cHardware.EqualsLiteral("harmony") ||
+          cHardware.EqualsLiteral("picasso") ||
+          cHardware.EqualsLiteral("picasso_e") ||
+          cHardware.EqualsLiteral("ventana") ||
+          cHardware.EqualsLiteral("rk30board")) {
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_STAGE_HW";
+        return NS_OK;
+      }
+
+      if (CompareVersions(mOSVersion.get(), "4.1.0") < 0) {
+        // Whitelist:
+        //   All Samsung ICS devices, except for:
+        //     Samsung SGH-I717 (Bug 845729)
+        //     Samsung SGH-I727 (Bug 845729)
+        //     Samsung SGH-I757 (Bug 845729)
+        //   All Galaxy nexus ICS devices
+        //   Sony Xperia Ion (LT28) ICS devices
+        bool isWhitelisted =
+            cModel.Equals("LT28h", nsCaseInsensitiveCStringComparator) ||
+            cManufacturer.Equals("samsung",
+                                 nsCaseInsensitiveCStringComparator) ||
+            cModel.Equals(
+                "galaxy nexus",
+                nsCaseInsensitiveCStringComparator);  // some Galaxy Nexus
+                                                      // have
+                                                      // manufacturer=amazon
+
+        if (cModel.LowerCaseFindASCII("sgh-i717") != -1 ||
+            cModel.LowerCaseFindASCII("sgh-i727") != -1 ||
+            cModel.LowerCaseFindASCII("sgh-i757") != -1) {
+          isWhitelisted = false;
+        }
+
+        if (!isWhitelisted) {
+          *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+          aFailureId = "FEATURE_FAILURE_4_1_HW";
+          return NS_OK;
+        }
+      } else if (CompareVersions(mOSVersion.get(), "4.2.0") < 0) {
+        // Whitelist:
+        //   All JB phones except for those in blocklist below
+        // Blocklist:
+        //   Samsung devices from bug 812881 and 853522.
+        //   Motorola XT890 from bug 882342.
+        bool isBlocklisted = cModel.LowerCaseFindASCII("gt-p3100") != -1 ||
+                             cModel.LowerCaseFindASCII("gt-p3110") != -1 ||
+                             cModel.LowerCaseFindASCII("gt-p3113") != -1 ||
+                             cModel.LowerCaseFindASCII("gt-p5100") != -1 ||
+                             cModel.LowerCaseFindASCII("gt-p5110") != -1 ||
+                             cModel.LowerCaseFindASCII("gt-p5113") != -1 ||
+                             cModel.LowerCaseFindASCII("xt890") != -1;
+
+        if (isBlocklisted) {
+          *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+          aFailureId = "FEATURE_FAILURE_4_2_HW";
+          return NS_OK;
+        }
+      } else if (CompareVersions(mOSVersion.get(), "4.3.0") < 0) {
+        // Blocklist all Sony devices
+        if (cManufacturer.LowerCaseFindASCII("sony") != -1) {
+          *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+          aFailureId = "FEATURE_FAILURE_4_3_SONY";
+          return NS_OK;
+        }
+      }
+    }
+
+    if (aFeature == FEATURE_WEBRTC_HW_ACCELERATION_ENCODE) {
+      if (jni::IsAvailable()) {
+        *aStatus = WebRtcHwVp8EncodeSupported();
+        aFailureId = "FEATURE_FAILURE_WEBRTC_ENCODE";
+        return NS_OK;
+      }
+    }
+    if (aFeature == FEATURE_WEBRTC_HW_ACCELERATION_DECODE) {
+      if (jni::IsAvailable()) {
+        *aStatus = WebRtcHwVp8DecodeSupported();
+        aFailureId = "FEATURE_FAILURE_WEBRTC_DECODE";
+        return NS_OK;
+      }
+    }
+    if (aFeature == FEATURE_WEBRTC_HW_ACCELERATION_H264) {
+      if (jni::IsAvailable()) {
+        *aStatus = WebRtcHwH264Supported();
+        aFailureId = "FEATURE_FAILURE_WEBRTC_H264";
+        return NS_OK;
+      }
+    }
+    if (aFeature == FEATURE_VP8_HW_DECODE ||
+        aFeature == FEATURE_VP9_HW_DECODE) {
+      NS_LossyConvertUTF16toASCII model(mModel);
+      bool isBlocked =
+          // GIFV crash, see bug 1232911.
+          model.Equals("GT-N8013", nsCaseInsensitiveCStringComparator);
+
+      if (isBlocked) {
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_VPx";
+      } else {
+        *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+      }
+      return NS_OK;
+    }
+
+    if (aFeature == FEATURE_WEBRENDER) {
+      const bool isMali4xx =
+          mGLStrings->Renderer().LowerCaseFindASCII("mali-4") >= 0;
+
+      const bool isPowerVrG6110 =
+          mGLStrings->Renderer().LowerCaseFindASCII("powervr rogue g6110") >= 0;
+
+      const bool isVivanteGC7000UL =
+          mGLStrings->Renderer().LowerCaseFindASCII("vivante gc7000ul") >= 0;
+
+      const bool isPowerVrFenceSyncCrash =
+          (mGLStrings->Renderer().LowerCaseFindASCII("powervr rogue g6200") >=
+               0 ||
+           mGLStrings->Renderer().LowerCaseFindASCII("powervr rogue g6430") >=
+               0 ||
+           mGLStrings->Renderer().LowerCaseFindASCII("powervr rogue gx6250") >=
+               0) &&
+          (mGLStrings->Version().Find("3283119") >= 0 ||
+           mGLStrings->Version().Find("3443629") >= 0 ||
+           mGLStrings->Version().Find("3573678") >= 0 ||
+           mGLStrings->Version().Find("3830101") >= 0);
+
+      if (isMali4xx) {
+        // Mali 4xx does not support GLES 3.
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_NO_GLES_3";
+      } else if (isPowerVrG6110) {
+        // Blocked on PowerVR Rogue G6110 due to bug 1742986 and bug 1717863.
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_POWERVR_G6110";
+      } else if (isVivanteGC7000UL) {
+        // Blocked on Vivante GC7000UL due to bug 1719327.
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_VIVANTE_GC7000UL";
+      } else if (isPowerVrFenceSyncCrash) {
+        // Blocked on various PowerVR GPUs due to bug 1773128.
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_POWERVR_FENCE_SYNC_CRASH";
+      } else {
+        *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+      }
+      return NS_OK;
+    }
+
+    if (aFeature == FEATURE_WEBRENDER_SCISSORED_CACHE_CLEARS) {
+      // Emulator with SwiftShader is buggy when attempting to clear picture
+      // cache textures with a scissor rect set.
+      const bool isEmulatorSwiftShader =
+          mGLStrings->Renderer().Find(
+              "Android Emulator OpenGL ES Translator (Google SwiftShader)") >=
+          0;
+      if (isEmulatorSwiftShader) {
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_BUG_1603515";
+      } else {
+        *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+      }
+      return NS_OK;
+    }
+
+    if (aFeature == FEATURE_WEBRENDER_SHADER_CACHE) {
+      // Program binaries are known to be buggy on Adreno 3xx. While we haven't
+      // encountered any correctness or stability issues with them, loading them
+      // fails more often than not, so is a waste of time. Better to just not
+      // even attempt to cache them. See bug 1615574.
+      const bool isAdreno3xx =
+          mGLStrings->Renderer().LowerCaseFindASCII("adreno (tm) 3") >= 0;
+      if (isAdreno3xx) {
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_ADRENO_3XX";
+      } else {
+        *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+      }
+    }
+
+    if (aFeature == FEATURE_WEBRENDER_OPTIMIZED_SHADERS) {
+      // Optimized shaders result in completely broken rendering on some Mali-T
+      // devices. We have seen this on T6xx, T7xx, and T8xx on android versions
+      // up to 5.1, and on T6xx on versions up to android 7.1. As a precaution
+      // disable for all Mali-T regardless of version. See bug 1689064 and bug
+      // 1707283 for details.
+      const bool isMaliT =
+          mGLStrings->Renderer().LowerCaseFindASCII("mali-t") >= 0;
+      if (isMaliT) {
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_BUG_1689064";
+      } else {
+        *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+      }
+      return NS_OK;
+    }
+
+    if (aFeature == FEATURE_WEBRENDER_PARTIAL_PRESENT) {
+      // Block partial present on some devices due to rendering issues.
+      // On Mali-Txxx due to bug 1680087 and bug 1707815.
+      // On Adreno 3xx GPUs due to bug 1695771.
+      const bool isMaliT =
+          mGLStrings->Renderer().LowerCaseFindASCII("mali-t") >= 0;
+      const bool isAdreno3xx =
+          mGLStrings->Renderer().LowerCaseFindASCII("adreno (tm) 3") >= 0;
+      if (isMaliT || isAdreno3xx) {
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_BUG_1680087_1695771_1707815";
+      } else {
+        *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+      }
+      return NS_OK;
+    }
+  }
+
+  if (aFeature == FEATURE_GL_SWIZZLE) {
+    // Swizzling appears to be buggy on PowerVR Rogue devices with webrender.
+    // See bug 1704783.
+    const bool isPowerVRRogue =
+        mGLStrings->Renderer().LowerCaseFindASCII("powervr rogue") >= 0;
+    if (isPowerVRRogue) {
+      *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+      aFailureId = "FEATURE_FAILURE_POWERVR_ROGUE";
+    } else {
+      *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+    }
+    return NS_OK;
+  }
+
+  return GfxInfoBase::GetFeatureStatusImpl(
+      aFeature, aStatus, aSuggestedDriverVersion, aDriverInfo, aFailureId, &os);
+}
+
+static nsCString FeatureCacheOsVerPrefName(int32_t aFeature) {
+  nsCString osPrefName;
+  osPrefName.AppendASCII("gfxinfo.cache.");
+  osPrefName.AppendInt(aFeature);
+  osPrefName.AppendASCII(".osver");
+  return osPrefName;
+}
+
+static nsCString FeatureCacheAppVerPrefName(int32_t aFeature) {
+  nsCString osPrefName;
+  osPrefName.AppendASCII("gfxinfo.cache.");
+  osPrefName.AppendInt(aFeature);
+  osPrefName.AppendASCII(".appver");
+  return osPrefName;
+}
+
+static nsCString FeatureCacheValuePrefName(int32_t aFeature) {
+  nsCString osPrefName;
+  osPrefName.AppendASCII("gfxinfo.cache.");
+  osPrefName.AppendInt(aFeature);
+  osPrefName.AppendASCII(".value");
+  return osPrefName;
+}
+
+static bool GetCachedFeatureVal(int32_t aFeature, uint32_t aExpectedOsVer,
+                                const nsCString& aCurrentAppVer,
+                                int32_t& aOutStatus) {
+  uint32_t osVer = 0;
+  nsresult rv =
+      Preferences::GetUint(FeatureCacheOsVerPrefName(aFeature).get(), &osVer);
+  if (NS_FAILED(rv) || osVer != aExpectedOsVer) {
+    return false;
+  }
+  // Bug 1804287 requires we invalidate cached values for new builds to allow
+  // for code changes to modify the features support.
+  nsAutoCString cachedAppVersion;
+  rv = Preferences::GetCString(FeatureCacheAppVerPrefName(aFeature).get(),
+                               cachedAppVersion);
+  if (NS_FAILED(rv) || !aCurrentAppVer.Equals(cachedAppVersion)) {
+    return false;
+  }
+  int32_t status = 0;
+  rv = Preferences::GetInt(FeatureCacheValuePrefName(aFeature).get(), &status);
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+  aOutStatus = status;
+  return true;
+}
+
+static void SetCachedFeatureVal(int32_t aFeature, uint32_t aOsVer,
+                                const nsCString& aCurrentAppVer,
+                                int32_t aStatus) {
+  // Ignore failures; not much we can do anyway.
+  Preferences::SetUint(FeatureCacheOsVerPrefName(aFeature).get(), aOsVer);
+  Preferences::SetCString(FeatureCacheAppVerPrefName(aFeature).get(),
+                          aCurrentAppVer);
+  Preferences::SetInt(FeatureCacheValuePrefName(aFeature).get(), aStatus);
+}
+
+int32_t GfxInfo::WebRtcHwVp8EncodeSupported() {
+  MOZ_ASSERT(jni::IsAvailable());
+
+  // The Android side of this calculation is very slow, so we cache the result
+  // in preferences, invalidating if the OS version changes.
+
+  int32_t status = 0;
+  const auto& currentAppVersion = GfxInfoBase::GetApplicationVersion();
+  if (GetCachedFeatureVal(FEATURE_WEBRTC_HW_ACCELERATION_ENCODE,
+                          mOSVersionInteger, currentAppVersion, status)) {
+    return status;
+  }
+
+  status = java::GeckoAppShell::HasHWVP8Encoder()
+               ? nsIGfxInfo::FEATURE_STATUS_OK
+               : nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+
+  SetCachedFeatureVal(FEATURE_WEBRTC_HW_ACCELERATION_ENCODE, mOSVersionInteger,
+                      currentAppVersion, status);
+
+  return status;
+}
+
+int32_t GfxInfo::WebRtcHwVp8DecodeSupported() {
+  MOZ_ASSERT(jni::IsAvailable());
+
+  // The Android side of this caclulation is very slow, so we cache the result
+  // in preferences, invalidating if the OS version changes.
+
+  int32_t status = 0;
+  const auto& appVersion = GfxInfoBase::GetApplicationVersion();
+  if (GetCachedFeatureVal(FEATURE_WEBRTC_HW_ACCELERATION_DECODE,
+                          mOSVersionInteger, appVersion, status)) {
+    return status;
+  }
+
+  status = java::GeckoAppShell::HasHWVP8Decoder()
+               ? nsIGfxInfo::FEATURE_STATUS_OK
+               : nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+
+  SetCachedFeatureVal(FEATURE_WEBRTC_HW_ACCELERATION_DECODE, mOSVersionInteger,
+                      appVersion, status);
+
+  return status;
+}
+
+int32_t GfxInfo::WebRtcHwH264Supported() {
+  MOZ_ASSERT(jni::IsAvailable());
+
+  // The Android side of this calculation is very slow, so we cache the result
+  // in preferences, invalidating if the OS version changes.
+
+  int32_t status = 0;
+  const auto& currentAppVersion = GfxInfoBase::GetApplicationVersion();
+  if (GetCachedFeatureVal(FEATURE_WEBRTC_HW_ACCELERATION_H264,
+                          mOSVersionInteger, currentAppVersion, status)) {
+    return status;
+  }
+
+  status = java::HardwareCodecCapabilityUtils::HasHWH264()
+               ? nsIGfxInfo::FEATURE_STATUS_OK
+               : nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+
+  SetCachedFeatureVal(FEATURE_WEBRTC_HW_ACCELERATION_H264, mOSVersionInteger,
+                      currentAppVersion, status);
+
+  return status;
+}
+
+#ifdef DEBUG
+
+// Implement nsIGfxInfoDebug
+
+NS_IMETHODIMP GfxInfo::SpoofVendorID(const nsAString& aVendorID) {
+  mGLStrings->SpoofVendor(NS_LossyConvertUTF16toASCII(aVendorID));
+  return NS_OK;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofDeviceID(const nsAString& aDeviceID) {
+  mGLStrings->SpoofRenderer(NS_LossyConvertUTF16toASCII(aDeviceID));
+  return NS_OK;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofDriverVersion(const nsAString& aDriverVersion) {
+  mGLStrings->SpoofVersion(NS_LossyConvertUTF16toASCII(aDriverVersion));
+  return NS_OK;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofOSVersion(uint32_t aVersion) {
+  EnsureInitialized();
+  mOSVersion = aVersion;
+  return NS_OK;
+}
+
+#endif
+
+nsString GfxInfo::Model() {
+  EnsureInitialized();
+  return mModel;
+}
+
+nsString GfxInfo::Hardware() {
+  EnsureInitialized();
+  return mHardware;
+}
+
+nsString GfxInfo::Product() {
+  EnsureInitialized();
+  return mProduct;
+}
+
+nsString GfxInfo::Manufacturer() {
+  EnsureInitialized();
+  return mManufacturer;
+}
+
+uint32_t GfxInfo::OperatingSystemVersion() {
+  EnsureInitialized();
+  return mOSVersionInteger;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/GfxInfo.h b/widget/android/GfxInfo.h
new file mode 100644
index 0000000000..7a963b0275
--- /dev/null
+++ b/widget/android/GfxInfo.h
@@ -0,0 +1,109 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_GfxInfo_h__
+#define __mozilla_widget_GfxInfo_h__
+
+#include "GfxInfoBase.h"
+#include "GfxDriverInfo.h"
+
+#include "nsString.h"
+#include "mozilla/UniquePtr.h"
+
+namespace mozilla {
+
+namespace widget {
+
+class GfxInfo : public GfxInfoBase {
+ private:
+  ~GfxInfo();
+
+ public:
+  GfxInfo();
+
+  // We only declare the subset of nsIGfxInfo that we actually implement. The
+  // rest is brought forward from GfxInfoBase.
+  NS_IMETHOD GetD2DEnabled(bool* aD2DEnabled) override;
+  NS_IMETHOD GetDWriteEnabled(bool* aDWriteEnabled) override;
+  NS_IMETHOD GetDWriteVersion(nsAString& aDwriteVersion) override;
+  NS_IMETHOD GetEmbeddedInFirefoxReality(
+      bool* aEmbeddedInFirefoxReality) override;
+  NS_IMETHOD GetHasBattery(bool* aHasBattery) override;
+  NS_IMETHOD GetCleartypeParameters(nsAString& aCleartypeParams) override;
+  NS_IMETHOD GetWindowProtocol(nsAString& aWindowProtocol) override;
+  NS_IMETHOD GetTestType(nsAString& aTestType) override;
+  NS_IMETHOD GetAdapterDescription(nsAString& aAdapterDescription) override;
+  NS_IMETHOD GetAdapterDriver(nsAString& aAdapterDriver) override;
+  NS_IMETHOD GetAdapterVendorID(nsAString& aAdapterVendorID) override;
+  NS_IMETHOD GetAdapterDeviceID(nsAString& aAdapterDeviceID) override;
+  NS_IMETHOD GetAdapterSubsysID(nsAString& aAdapterSubsysID) override;
+  NS_IMETHOD GetAdapterRAM(uint32_t* aAdapterRAM) override;
+  NS_IMETHOD GetAdapterDriverVendor(nsAString& aAdapterDriverVendor) override;
+  NS_IMETHOD GetAdapterDriverVersion(nsAString& aAdapterDriverVersion) override;
+  NS_IMETHOD GetAdapterDriverDate(nsAString& aAdapterDriverDate) override;
+  NS_IMETHOD GetAdapterDescription2(nsAString& aAdapterDescription) override;
+  NS_IMETHOD GetAdapterDriver2(nsAString& aAdapterDriver) override;
+  NS_IMETHOD GetAdapterVendorID2(nsAString& aAdapterVendorID) override;
+  NS_IMETHOD GetAdapterDeviceID2(nsAString& aAdapterDeviceID) override;
+  NS_IMETHOD GetAdapterSubsysID2(nsAString& aAdapterSubsysID) override;
+  NS_IMETHOD GetAdapterRAM2(uint32_t* aAdapterRAM) override;
+  NS_IMETHOD GetAdapterDriverVendor2(nsAString& aAdapterDriverVendor) override;
+  NS_IMETHOD GetAdapterDriverVersion2(
+      nsAString& aAdapterDriverVersion) override;
+  NS_IMETHOD GetAdapterDriverDate2(nsAString& aAdapterDriverDate) override;
+  NS_IMETHOD GetIsGPU2Active(bool* aIsGPU2Active) override;
+  NS_IMETHOD GetDrmRenderDevice(nsACString& aDrmRenderDevice) override;
+  using GfxInfoBase::GetFeatureStatus;
+  using GfxInfoBase::GetFeatureSuggestedDriverVersion;
+
+  void EnsureInitialized();
+
+  virtual nsString Model() override;
+  virtual nsString Hardware() override;
+  virtual nsString Product() override;
+  virtual nsString Manufacturer() override;
+
+#ifdef DEBUG
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIGFXINFODEBUG
+#endif
+
+  virtual uint32_t OperatingSystemVersion() override;
+
+ protected:
+  OperatingSystem GetOperatingSystem() override {
+    return OperatingSystem::Android;
+  }
+  virtual nsresult GetFeatureStatusImpl(
+      int32_t aFeature, int32_t* aStatus, nsAString& aSuggestedDriverVersion,
+      const nsTArray<GfxDriverInfo>& aDriverInfo, nsACString& aFailureId,
+      OperatingSystem* aOS = nullptr) override;
+  virtual const nsTArray<GfxDriverInfo>& GetGfxDriverInfo() override;
+
+ private:
+  void AddCrashReportAnnotations();
+  int32_t WebRtcHwVp8EncodeSupported();
+  int32_t WebRtcHwVp8DecodeSupported();
+  int32_t WebRtcHwH264Supported();
+
+  bool mInitialized;
+
+  class GLStrings;
+  UniquePtr<GLStrings> mGLStrings;
+
+  nsCString mAdapterDescription;
+
+  nsString mModel, mHardware, mManufacturer, mProduct;
+  nsCString mOSVersion;
+  uint32_t mOSVersionInteger;
+  int32_t mSDKVersion;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __mozilla_widget_GfxInfo_h__ */
diff --git a/widget/android/ImageDecoderSupport.cpp b/widget/android/ImageDecoderSupport.cpp
new file mode 100644
index 0000000000..4418b79746
--- /dev/null
+++ b/widget/android/ImageDecoderSupport.cpp
@@ -0,0 +1,185 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ImageDecoderSupport.h"
+
+#include "imgINotificationObserver.h"
+#include "imgITools.h"
+#include "imgINotificationObserver.h"
+#include "gfxUtils.h"
+#include "AndroidGraphics.h"
+#include "JavaExceptions.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/gfx/Swizzle.h"
+#include "mozilla/java/ImageWrappers.h"
+#include "nsNetUtil.h"
+
+using namespace mozilla::gfx;
+
+namespace mozilla {
+namespace widget {
+
+namespace {
+
+class ImageCallbackHelper;
+
+HashSet<RefPtr<ImageCallbackHelper>, PointerHasher<ImageCallbackHelper*>>
+    gDecodeRequests;
+
+class ImageCallbackHelper : public imgIContainerCallback,
+                            public imgINotificationObserver {
+ public:
+  NS_DECL_ISUPPORTS
+
+  void CompleteExceptionally(nsresult aRv) {
+    nsPrintfCString error("Could not process image: 0x%08X", uint32_t(aRv));
+    mResult->CompleteExceptionally(
+        java::Image::ImageProcessingException::New(error.get())
+            .Cast<jni::Throwable>());
+    gDecodeRequests.remove(this);
+  }
+
+  void Complete(DataSourceSurface::ScopedMap& aSourceSurface, int32_t width,
+                int32_t height) {
+    auto pixels = mozilla::jni::ByteBuffer::New(
+        reinterpret_cast<int8_t*>(aSourceSurface.GetData()),
+        aSourceSurface.GetStride() * height);
+    auto bitmap = java::sdk::Bitmap::CreateBitmap(
+        width, height, java::sdk::Bitmap::Config::ARGB_8888());
+    bitmap->CopyPixelsFromBuffer(pixels);
+    mResult->Complete(bitmap);
+    gDecodeRequests.remove(this);
+  }
+
+  ImageCallbackHelper(java::GeckoResult::Param aResult, int32_t aDesiredLength)
+      : mResult(aResult), mDesiredLength(aDesiredLength), mImage(nullptr) {
+    MOZ_ASSERT(mResult);
+  }
+
+  NS_IMETHOD
+  OnImageReady(imgIContainer* aImage, nsresult aStatus) override {
+    // Let's make sure we are alive until the request completes
+    MOZ_ALWAYS_TRUE(gDecodeRequests.putNew(this));
+
+    if (NS_FAILED(aStatus)) {
+      CompleteExceptionally(aStatus);
+      return aStatus;
+    }
+
+    mImage = aImage;
+    return mImage->StartDecoding(
+        imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY,
+        imgIContainer::FRAME_FIRST);
+  }
+
+  // This method assumes that the image is ready to be processed
+  nsresult SendBitmap() {
+    RefPtr<gfx::SourceSurface> surface;
+
+    NS_ENSURE_TRUE(mImage, NS_ERROR_FAILURE);
+    if (mDesiredLength > 0) {
+      surface = mImage->GetFrameAtSize(
+          gfx::IntSize(mDesiredLength, mDesiredLength),
+          imgIContainer::FRAME_FIRST,
+          imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
+    } else {
+      surface = mImage->GetFrame(
+          imgIContainer::FRAME_FIRST,
+          imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
+    }
+
+    NS_ENSURE_TRUE(surface, NS_ERROR_FAILURE);
+    RefPtr<DataSourceSurface> dataSurface = surface->GetDataSurface();
+
+    NS_ENSURE_TRUE(dataSurface, NS_ERROR_FAILURE);
+    int32_t width = dataSurface->GetSize().width;
+    int32_t height = dataSurface->GetSize().height;
+
+    DataSourceSurface::ScopedMap sourceMap(dataSurface,
+                                           DataSourceSurface::READ);
+
+    // Android's Bitmap only supports R8G8B8A8, so we need to convert the
+    // data to the right format
+    RefPtr<DataSourceSurface> destDataSurface =
+        Factory::CreateDataSourceSurfaceWithStride(dataSurface->GetSize(),
+                                                   SurfaceFormat::R8G8B8A8,
+                                                   sourceMap.GetStride());
+    NS_ENSURE_TRUE(destDataSurface, NS_ERROR_FAILURE);
+
+    DataSourceSurface::ScopedMap destMap(destDataSurface,
+                                         DataSourceSurface::READ_WRITE);
+
+    SwizzleData(sourceMap.GetData(), sourceMap.GetStride(),
+                surface->GetFormat(), destMap.GetData(), destMap.GetStride(),
+                SurfaceFormat::R8G8B8A8, destDataSurface->GetSize());
+
+    Complete(destMap, width, height);
+
+    return NS_OK;
+  }
+
+  void Notify(imgIRequest* aRequest, int32_t aType,
+              const nsIntRect* aData) override {
+    if (aType == imgINotificationObserver::DECODE_COMPLETE) {
+      nsresult status = SendBitmap();
+      if (NS_FAILED(status)) {
+        CompleteExceptionally(status);
+      }
+
+      // Breack the cyclic reference between `ImageDecoderListener` (which is a
+      // `imgIContainer`) and `ImageCallbackHelper`.
+      mImage = nullptr;
+    }
+  }
+
+ private:
+  const java::GeckoResult::GlobalRef mResult;
+  int32_t mDesiredLength;
+  nsCOMPtr<imgIContainer> mImage;
+  virtual ~ImageCallbackHelper() {}
+};
+
+NS_IMPL_ISUPPORTS(ImageCallbackHelper, imgIContainerCallback,
+                  imgINotificationObserver)
+
+}  // namespace
+
+/* static */ void ImageDecoderSupport::Decode(jni::String::Param aUri,
+                                              int32_t aDesiredLength,
+                                              jni::Object::Param aResult) {
+  auto result = java::GeckoResult::LocalRef(aResult);
+  RefPtr<ImageCallbackHelper> helper =
+      new ImageCallbackHelper(result, aDesiredLength);
+
+  nsresult rv = DecodeInternal(aUri->ToString(), helper, helper);
+  if (NS_FAILED(rv)) {
+    helper->OnImageReady(nullptr, rv);
+  }
+}
+
+/* static */ nsresult ImageDecoderSupport::DecodeInternal(
+    const nsAString& aUri, imgIContainerCallback* aCallback,
+    imgINotificationObserver* aObserver) {
+  nsCOMPtr<imgITools> imgTools = do_GetService("@mozilla.org/image/tools;1");
+  if (NS_WARN_IF(!imgTools)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsIURI> uri;
+  nsresult rv = NS_NewURI(getter_AddRefs(uri), aUri);
+  NS_ENSURE_SUCCESS(rv, NS_ERROR_MALFORMED_URI);
+
+  nsCOMPtr<nsIChannel> channel;
+  rv = NS_NewChannel(getter_AddRefs(channel), uri,
+                     nsContentUtils::GetSystemPrincipal(),
+                     nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
+                     nsIContentPolicy::TYPE_IMAGE);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return imgTools->DecodeImageFromChannelAsync(uri, channel, aCallback,
+                                               aObserver);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/ImageDecoderSupport.h b/widget/android/ImageDecoderSupport.h
new file mode 100644
index 0000000000..d38b3e7e1b
--- /dev/null
+++ b/widget/android/ImageDecoderSupport.h
@@ -0,0 +1,30 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ImageDecoderSupport_h__
+#define ImageDecoderSupport_h__
+
+#include "mozilla/java/ImageDecoderNatives.h"
+
+class imgIContainerCallback;
+
+namespace mozilla {
+namespace widget {
+
+class ImageDecoderSupport final
+    : public java::ImageDecoder::Natives<ImageDecoderSupport> {
+ public:
+  static void Decode(jni::String::Param aUri, int32_t aDesiredLength,
+                     jni::Object::Param aResult);
+
+ private:
+  static nsresult DecodeInternal(const nsAString& aUri,
+                                 imgIContainerCallback* aCallback,
+                                 imgINotificationObserver* aObserver);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // ImageDecoderSupport_h__
diff --git a/widget/android/InProcessAndroidCompositorWidget.cpp b/widget/android/InProcessAndroidCompositorWidget.cpp
new file mode 100644
index 0000000000..1ae221acb9
--- /dev/null
+++ b/widget/android/InProcessAndroidCompositorWidget.cpp
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HeadlessCompositorWidget.h"
+#include "HeadlessWidget.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+
+#include "InProcessAndroidCompositorWidget.h"
+#include "nsWindow.h"
+
+namespace mozilla {
+namespace widget {
+
+/* static */
+RefPtr<CompositorWidget> CompositorWidget::CreateLocal(
+    const CompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions, nsIWidget* aWidget) {
+  if (aInitData.type() ==
+      CompositorWidgetInitData::THeadlessCompositorWidgetInitData) {
+    return new HeadlessCompositorWidget(
+        aInitData.get_HeadlessCompositorWidgetInitData(), aOptions,
+        static_cast<HeadlessWidget*>(aWidget));
+  } else {
+    return new InProcessAndroidCompositorWidget(
+        aInitData.get_AndroidCompositorWidgetInitData(), aOptions,
+        static_cast<nsWindow*>(aWidget));
+  }
+}
+
+InProcessAndroidCompositorWidget::InProcessAndroidCompositorWidget(
+    const AndroidCompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions, nsWindow* aWindow)
+    : AndroidCompositorWidget(aInitData, aOptions), mWindow(aWindow) {}
+
+void InProcessAndroidCompositorWidget::ObserveVsync(VsyncObserver* aObserver) {
+  if (RefPtr<CompositorVsyncDispatcher> cvd =
+          mWindow->GetCompositorVsyncDispatcher()) {
+    cvd->SetCompositorVsyncObserver(aObserver);
+  }
+}
+
+nsIWidget* InProcessAndroidCompositorWidget::RealWidget() { return mWindow; }
+
+void InProcessAndroidCompositorWidget::OnCompositorSurfaceChanged() {
+  mSurface = java::sdk::Surface::Ref::From(
+      static_cast<jobject>(mWindow->GetNativeData(NS_JAVA_SURFACE)));
+}
+
+void InProcessAndroidCompositorWidget::NotifyClientSizeChanged(
+    const LayoutDeviceIntSize& aClientSize) {
+  AndroidCompositorWidget::NotifyClientSizeChanged(aClientSize);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/InProcessAndroidCompositorWidget.h b/widget/android/InProcessAndroidCompositorWidget.h
new file mode 100644
index 0000000000..b7ba280d5c
--- /dev/null
+++ b/widget/android/InProcessAndroidCompositorWidget.h
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_android_InProcessAndroidCompositorWidget_h
+#define widget_android_InProcessAndroidCompositorWidget_h
+
+#include "AndroidCompositorWidget.h"
+#include "CompositorWidget.h"
+
+class nsWindow;
+
+namespace mozilla {
+namespace widget {
+
+class InProcessAndroidCompositorWidget final
+    : public AndroidCompositorWidget,
+      public PlatformCompositorWidgetDelegate {
+ public:
+  InProcessAndroidCompositorWidget(
+      const AndroidCompositorWidgetInitData& aInitData,
+      const layers::CompositorOptions& aOptions, nsWindow* aWidget);
+
+  // CompositorWidget overrides
+
+  void ObserveVsync(VsyncObserver* aObserver) override;
+  nsIWidget* RealWidget() override;
+  CompositorWidgetDelegate* AsDelegate() override { return this; }
+
+  // PlatformCompositorWidgetDelegate overrides
+
+  void NotifyClientSizeChanged(const LayoutDeviceIntSize& aClientSize) override;
+
+ private:
+  // AndroidCompositorWidget overrides
+  void OnCompositorSurfaceChanged() override;
+
+  nsWindow* mWindow;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_android_InProcessAndroidCompositorWidget_h
diff --git a/widget/android/MediaKeysEventSourceFactory.cpp b/widget/android/MediaKeysEventSourceFactory.cpp
new file mode 100644
index 0000000000..b52919d4cc
--- /dev/null
+++ b/widget/android/MediaKeysEventSourceFactory.cpp
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaKeysEventSourceFactory.h"
+
+namespace mozilla {
+namespace widget {
+
+mozilla::dom::MediaControlKeySource* CreateMediaControlKeySource() {
+  // GeckoView uses MediaController.webidl for media session events and control,
+  // see bug 1623715.
+  return nullptr;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/PCompositorWidget.ipdl b/widget/android/PCompositorWidget.ipdl
new file mode 100644
index 0000000000..35a150cbba
--- /dev/null
+++ b/widget/android/PCompositorWidget.ipdl
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=99: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PCompositorBridge;
+
+using mozilla::LayoutDeviceIntSize from "Units.h";
+
+namespace mozilla {
+namespace widget {
+
+[ManualDealloc, ChildImpl=virtual, ParentImpl=virtual]
+sync protocol PCompositorWidget
+{
+  manager PCompositorBridge;
+
+parent:
+  async __delete__();
+
+  async NotifyClientSizeChanged(LayoutDeviceIntSize aClientSize);
+
+child:
+  async ObserveVsync();
+  async UnobserveVsync();
+};
+
+} // namespace widget
+} // namespace mozilla
diff --git a/widget/android/PlatformWidgetTypes.ipdlh b/widget/android/PlatformWidgetTypes.ipdlh
new file mode 100644
index 0000000000..62ac0df9ff
--- /dev/null
+++ b/widget/android/PlatformWidgetTypes.ipdlh
@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=99: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include HeadlessWidgetTypes;
+
+include "mozilla/GfxMessageUtils.h";
+
+using mozilla::LayoutDeviceIntSize from "Units.h";
+
+namespace mozilla {
+namespace widget {
+
+struct AndroidCompositorWidgetInitData
+{
+  int32_t widgetId;
+  LayoutDeviceIntSize clientSize;
+};
+
+union CompositorWidgetInitData
+{
+  AndroidCompositorWidgetInitData;
+  HeadlessCompositorWidgetInitData;
+};
+
+} // namespace widget
+} // namespace mozilla
diff --git a/widget/android/ScreenHelperAndroid.cpp b/widget/android/ScreenHelperAndroid.cpp
new file mode 100644
index 0000000000..33c91fe6e0
--- /dev/null
+++ b/widget/android/ScreenHelperAndroid.cpp
@@ -0,0 +1,70 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set sw=2 ts=4 expandtab:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScreenHelperAndroid.h"
+#include "AndroidRect.h"
+#include "nsThreadUtils.h"
+
+#include <mozilla/jni/Refs.h>
+
+#include "AndroidVsync.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/java/GeckoAppShellWrappers.h"
+#include "mozilla/java/ScreenManagerHelperNatives.h"
+#include "mozilla/widget/ScreenManager.h"
+#include "nsXULAppAPI.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+static ScreenHelperAndroid* gHelper = nullptr;
+
+class ScreenHelperAndroid::ScreenHelperSupport final
+    : public java::ScreenManagerHelper::Natives<ScreenHelperSupport> {
+ public:
+  typedef java::ScreenManagerHelper::Natives<ScreenHelperSupport> Base;
+
+  static void RefreshScreenInfo() { gHelper->Refresh(); }
+};
+
+static already_AddRefed<Screen> MakePrimaryScreen() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  java::sdk::Rect::LocalRef rect = java::GeckoAppShell::GetScreenSize();
+  LayoutDeviceIntRect bounds = LayoutDeviceIntRect(
+      rect->Left(), rect->Top(), rect->Width(), rect->Height());
+  uint32_t depth = java::GeckoAppShell::GetScreenDepth();
+  float density = java::GeckoAppShell::GetDensity();
+  float dpi = java::GeckoAppShell::GetDpi();
+  auto orientation =
+      hal::ScreenOrientation(java::GeckoAppShell::GetScreenOrientation());
+  uint16_t angle = java::GeckoAppShell::GetScreenAngle();
+  float refreshRate = java::GeckoAppShell::GetScreenRefreshRate();
+  return MakeAndAddRef<Screen>(bounds, bounds, depth, depth, refreshRate,
+                               DesktopToLayoutDeviceScale(density),
+                               CSSToLayoutDeviceScale(1.0f), dpi,
+                               Screen::IsPseudoDisplay::No, orientation, angle);
+}
+
+ScreenHelperAndroid::ScreenHelperAndroid() {
+  MOZ_ASSERT(!gHelper);
+  gHelper = this;
+
+  ScreenHelperSupport::Base::Init();
+
+  Refresh();
+}
+
+ScreenHelperAndroid::~ScreenHelperAndroid() { gHelper = nullptr; }
+
+void ScreenHelperAndroid::Refresh() {
+  AutoTArray<RefPtr<Screen>, 1> screens;
+  screens.AppendElement(MakePrimaryScreen());
+  ScreenManager::Refresh(std::move(screens));
+
+  if (RefPtr<AndroidVsync> vsync = AndroidVsync::GetInstance()) {
+    vsync->OnMaybeUpdateRefreshRate();
+  }
+}
diff --git a/widget/android/ScreenHelperAndroid.h b/widget/android/ScreenHelperAndroid.h
new file mode 100644
index 0000000000..c7015ee873
--- /dev/null
+++ b/widget/android/ScreenHelperAndroid.h
@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: ts=4 sw=2 expandtab:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ScreenHelperAndroid_h___
+#define ScreenHelperAndroid_h___
+
+#include "mozilla/widget/ScreenManager.h"
+#include "nsTHashMap.h"
+
+namespace mozilla {
+namespace widget {
+
+class ScreenHelperAndroid final : public ScreenManager::Helper {
+ public:
+  class ScreenHelperSupport;
+
+  ScreenHelperAndroid();
+  ~ScreenHelperAndroid();
+
+  void Refresh();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* ScreenHelperAndroid_h___ */
diff --git a/widget/android/Telemetry.h b/widget/android/Telemetry.h
new file mode 100644
index 0000000000..ea8f2dd418
--- /dev/null
+++ b/widget/android/Telemetry.h
@@ -0,0 +1,39 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_Telemetry_h__
+#define mozilla_widget_Telemetry_h__
+
+#include "mozilla/java/TelemetryUtilsNatives.h"
+#include "nsAppShell.h"
+#include "nsIAndroidBridge.h"
+
+#include "mozilla/TimeStamp.h"
+#include "mozilla/glean/GleanMetrics.h"
+
+namespace mozilla {
+namespace widget {
+
+class Telemetry final : public java::TelemetryUtils::Natives<Telemetry> {
+  Telemetry() = delete;
+
+ public:
+  static void AddHistogram(jni::String::Param aName, int32_t aValue) {
+    MOZ_ASSERT(aName);
+    nsCString name = aName->ToCString();
+    if (name.EqualsLiteral("GV_STARTUP_RUNTIME_MS")) {
+      glean::geckoview::startup_runtime.AccumulateRawDuration(
+          TimeDuration::FromMilliseconds(aValue));
+    } else if (name.EqualsLiteral("GV_CONTENT_PROCESS_LIFETIME_MS")) {
+      glean::geckoview::content_process_lifetime.AccumulateRawDuration(
+          TimeDuration::FromMilliseconds(aValue));
+    }
+  }
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_Telemetry_h__
diff --git a/widget/android/WebExecutorSupport.cpp b/widget/android/WebExecutorSupport.cpp
new file mode 100644
index 0000000000..44b9a4696e
--- /dev/null
+++ b/widget/android/WebExecutorSupport.cpp
@@ -0,0 +1,472 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <algorithm>
+
+#include "GeckoViewStreamListener.h"
+#include "InetAddress.h"  // for java::sdk::InetAddress and java::sdk::UnknownHostException
+#include "ReferrerInfo.h"
+#include "WebExecutorSupport.h"
+
+#include "nsIAsyncVerifyRedirectCallback.h"
+#include "nsICancelable.h"
+#include "nsIHttpChannel.h"
+#include "nsIHttpChannelInternal.h"
+#include "nsIHttpHeaderVisitor.h"
+#include "nsIInputStream.h"
+#include "nsIDNSService.h"
+#include "nsIDNSListener.h"
+#include "nsIDNSRecord.h"
+#include "nsINSSErrorsService.h"
+#include "nsContentUtils.h"
+#include "nsNetUtil.h"  // for NS_NewURI, NS_NewChannel, NS_NewStreamLoader
+#include "nsIPrivateBrowsingChannel.h"
+#include "nsIUploadChannel2.h"
+#include "nsIX509Cert.h"
+
+#include "mozilla/Preferences.h"
+#include "mozilla/net/CookieJarSettings.h"
+#include "mozilla/net/DNS.h"  // for NetAddr
+#include "mozilla/java/GeckoWebExecutorWrappers.h"
+#include "mozilla/java/WebMessageWrappers.h"
+#include "mozilla/java/WebRequestErrorWrappers.h"
+#include "mozilla/java/WebResponseWrappers.h"
+
+namespace mozilla {
+using namespace net;
+
+namespace widget {
+
+static void CompleteWithError(java::GeckoResult::Param aResult,
+                              nsresult aStatus, nsIChannel* aChannel) {
+  nsCOMPtr<nsINSSErrorsService> errSvc =
+      do_GetService("@mozilla.org/nss_errors_service;1");
+  MOZ_ASSERT(errSvc);
+
+  uint32_t errorClass;
+  nsresult rv = errSvc->GetErrorClass(aStatus, &errorClass);
+  if (NS_FAILED(rv)) {
+    errorClass = 0;
+  }
+
+  jni::ByteArray::LocalRef certBytes;
+  if (aChannel) {
+    std::tie(certBytes, std::ignore) =
+        GeckoViewStreamListener::CertificateFromChannel(aChannel);
+  }
+
+  java::WebRequestError::LocalRef error = java::WebRequestError::FromGeckoError(
+      int64_t(aStatus), NS_ERROR_GET_MODULE(aStatus), errorClass, certBytes);
+
+  aResult->CompleteExceptionally(error.Cast<jni::Throwable>());
+}
+
+static void CompleteWithError(java::GeckoResult::Param aResult,
+                              nsresult aStatus) {
+  CompleteWithError(aResult, aStatus, nullptr);
+}
+
+class ByteBufferStream final : public nsIInputStream {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+
+  explicit ByteBufferStream(jni::ByteBuffer::Param buffer)
+      : mBuffer(buffer), mPosition(0), mClosed(false) {
+    MOZ_ASSERT(mBuffer);
+    MOZ_ASSERT(mBuffer->Address());
+  }
+
+  NS_IMETHOD
+  Close() override {
+    mClosed = true;
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  Available(uint64_t* aResult) override {
+    if (mClosed) {
+      return NS_BASE_STREAM_CLOSED;
+    }
+
+    *aResult = (mBuffer->Capacity() - mPosition);
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  StreamStatus() override { return mClosed ? NS_BASE_STREAM_CLOSED : NS_OK; }
+
+  NS_IMETHOD
+  Read(char* aBuf, uint32_t aCount, uint32_t* aCountRead) override {
+    if (mClosed) {
+      return NS_BASE_STREAM_CLOSED;
+    }
+
+    *aCountRead = uint32_t(
+        std::min(uint64_t(mBuffer->Capacity() - mPosition), uint64_t(aCount)));
+
+    if (*aCountRead > 0) {
+      memcpy(aBuf, (char*)mBuffer->Address() + mPosition, *aCountRead);
+      mPosition += *aCountRead;
+    }
+
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  ReadSegments(nsWriteSegmentFun aWriter, void* aClosure, uint32_t aCount,
+               uint32_t* aResult) override {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  NS_IMETHOD
+  IsNonBlocking(bool* aResult) override {
+    *aResult = false;
+    return NS_OK;
+  }
+
+ protected:
+  virtual ~ByteBufferStream() {}
+
+  const jni::ByteBuffer::GlobalRef mBuffer;
+  uint64_t mPosition;
+  bool mClosed;
+};
+
+NS_IMPL_ISUPPORTS(ByteBufferStream, nsIInputStream)
+
+class LoaderListener final : public GeckoViewStreamListener {
+ public:
+  explicit LoaderListener(java::GeckoResult::Param aResult,
+                          bool aAllowRedirects, bool testStreamFailure)
+      : GeckoViewStreamListener(),
+        mResult(aResult),
+        mTestStreamFailure(testStreamFailure),
+        mAllowRedirects(aAllowRedirects) {
+    MOZ_ASSERT(mResult);
+  }
+
+  NS_IMETHOD
+  OnDataAvailable(nsIRequest* aRequest, nsIInputStream* aInputStream,
+                  uint64_t aOffset, uint32_t aCount) override {
+    MOZ_ASSERT(mStream);
+
+    if (mTestStreamFailure) {
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    // We only need this for the ReadSegments call, the value is unused.
+    uint32_t countRead;
+    nsresult rv =
+        aInputStream->ReadSegments(WriteSegment, this, aCount, &countRead);
+    NS_ENSURE_SUCCESS(rv, rv);
+    return rv;
+  }
+
+  NS_IMETHOD
+  AsyncOnChannelRedirect(nsIChannel* aOldChannel, nsIChannel* aNewChannel,
+                         uint32_t flags,
+                         nsIAsyncVerifyRedirectCallback* callback) override {
+    if (!mAllowRedirects) {
+      return NS_ERROR_ABORT;
+    }
+
+    callback->OnRedirectVerifyCallback(NS_OK);
+    return NS_OK;
+  }
+
+  void SendWebResponse(java::WebResponse::Param aResponse) override {
+    mResult->Complete(aResponse);
+  }
+
+  void CompleteWithError(nsresult aStatus, nsIChannel* aChannel) override {
+    mozilla::widget::CompleteWithError(mResult, aStatus, aChannel);
+  }
+
+  virtual ~LoaderListener() {}
+
+  const java::GeckoResult::GlobalRef mResult;
+  const bool mTestStreamFailure;
+  bool mAllowRedirects;
+};
+
+class DNSListener final : public nsIDNSListener {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+
+  DNSListener(const nsCString& aHost, java::GeckoResult::Param aResult)
+      : mHost(aHost), mResult(aResult) {}
+
+  NS_IMETHOD
+  OnLookupComplete(nsICancelable* aRequest, nsIDNSRecord* aRecord,
+                   nsresult aStatus) override {
+    if (NS_FAILED(aStatus)) {
+      CompleteUnknownHostError();
+      return NS_OK;
+    }
+
+    nsresult rv = CompleteWithRecord(aRecord);
+    if (NS_FAILED(rv)) {
+      CompleteUnknownHostError();
+      return NS_OK;
+    }
+
+    return NS_OK;
+  }
+
+  void CompleteUnknownHostError() {
+    java::sdk::UnknownHostException::LocalRef error =
+        java::sdk::UnknownHostException::New();
+    mResult->CompleteExceptionally(error.Cast<jni::Throwable>());
+  }
+
+ private:
+  nsresult CompleteWithRecord(nsIDNSRecord* aRecord) {
+    nsTArray<NetAddr> addrs;
+    nsCOMPtr<nsIDNSAddrRecord> rec = do_QueryInterface(aRecord);
+    if (!rec) {
+      return NS_ERROR_UNEXPECTED;
+    }
+    nsresult rv = rec->GetAddresses(addrs);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    jni::ByteArray::LocalRef bytes;
+    auto objects =
+        jni::ObjectArray::New<java::sdk::InetAddress>(addrs.Length());
+    for (size_t i = 0; i < addrs.Length(); i++) {
+      const auto& addr = addrs[i];
+      if (addr.raw.family == AF_INET) {
+        bytes = jni::ByteArray::New(
+            reinterpret_cast<const int8_t*>(&addr.inet.ip), 4);
+      } else if (addr.raw.family == AF_INET6) {
+        bytes = jni::ByteArray::New(
+            reinterpret_cast<const int8_t*>(&addr.inet6.ip), 16);
+      } else {
+        // We don't handle this, skip it.
+        continue;
+      }
+
+      objects->SetElement(i,
+                          java::sdk::InetAddress::GetByAddress(mHost, bytes));
+    }
+
+    mResult->Complete(objects);
+    return NS_OK;
+  }
+
+  virtual ~DNSListener() {}
+
+  const nsCString mHost;
+  const java::GeckoResult::GlobalRef mResult;
+};
+
+NS_IMPL_ISUPPORTS(DNSListener, nsIDNSListener)
+
+static nsresult ConvertCacheMode(int32_t mode, int32_t& result) {
+  switch (mode) {
+    case java::WebRequest::CACHE_MODE_DEFAULT:
+      result = nsIHttpChannelInternal::FETCH_CACHE_MODE_DEFAULT;
+      break;
+    case java::WebRequest::CACHE_MODE_NO_STORE:
+      result = nsIHttpChannelInternal::FETCH_CACHE_MODE_NO_STORE;
+      break;
+    case java::WebRequest::CACHE_MODE_RELOAD:
+      result = nsIHttpChannelInternal::FETCH_CACHE_MODE_RELOAD;
+      break;
+    case java::WebRequest::CACHE_MODE_NO_CACHE:
+      result = nsIHttpChannelInternal::FETCH_CACHE_MODE_NO_CACHE;
+      break;
+    case java::WebRequest::CACHE_MODE_FORCE_CACHE:
+      result = nsIHttpChannelInternal::FETCH_CACHE_MODE_FORCE_CACHE;
+      break;
+    case java::WebRequest::CACHE_MODE_ONLY_IF_CACHED:
+      result = nsIHttpChannelInternal::FETCH_CACHE_MODE_ONLY_IF_CACHED;
+      break;
+    default:
+      return NS_ERROR_UNEXPECTED;
+  }
+
+  return NS_OK;
+}
+
+static nsresult SetupHttpChannel(nsIHttpChannel* aHttpChannel,
+                                 nsIChannel* aChannel,
+                                 java::WebRequest::Param aRequest) {
+  const auto req = java::WebRequest::LocalRef(aRequest);
+  const auto reqBase = java::WebMessage::LocalRef(req.Cast<java::WebMessage>());
+
+  // Method
+  nsresult rv = aHttpChannel->SetRequestMethod(aRequest->Method()->ToCString());
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Headers
+  const auto keys = reqBase->GetHeaderKeys();
+  const auto values = reqBase->GetHeaderValues();
+  nsCString contentType;
+  for (size_t i = 0; i < keys->Length(); i++) {
+    const auto key = jni::String::LocalRef(keys->GetElement(i))->ToCString();
+    const auto value =
+        jni::String::LocalRef(values->GetElement(i))->ToCString();
+
+    if (key.LowerCaseEqualsASCII("content-type")) {
+      contentType = value;
+    }
+
+    // We clobber any duplicate keys here because we've already merged them
+    // in the upstream WebRequest.
+    rv = aHttpChannel->SetRequestHeader(key, value, false /* merge */);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Body
+  const auto body = req->Body();
+  if (body) {
+    nsCOMPtr<nsIInputStream> stream = new ByteBufferStream(body);
+
+    nsCOMPtr<nsIUploadChannel2> uploadChannel(do_QueryInterface(aChannel, &rv));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = uploadChannel->ExplicitSetUploadStream(
+        stream, contentType, -1, aRequest->Method()->ToCString(), false);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Referrer
+  RefPtr<nsIURI> referrerUri;
+  const auto referrer = req->Referrer();
+  if (referrer) {
+    rv = NS_NewURI(getter_AddRefs(referrerUri), referrer->ToString());
+    NS_ENSURE_SUCCESS(rv, NS_ERROR_MALFORMED_URI);
+  }
+
+  nsCOMPtr<nsIReferrerInfo> referrerInfo = new dom::ReferrerInfo(referrerUri);
+  rv = aHttpChannel->SetReferrerInfoWithoutClone(referrerInfo);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Cache mode
+  nsCOMPtr<nsIHttpChannelInternal> internalChannel(
+      do_QueryInterface(aChannel, &rv));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  int32_t cacheMode;
+  rv = ConvertCacheMode(req->CacheMode(), cacheMode);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = internalChannel->SetFetchCacheMode(cacheMode);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (req->BeConservative()) {
+    rv = internalChannel->SetBeConservative(true);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // We don't have any UI
+  rv = internalChannel->SetBlockAuthPrompt(true);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult WebExecutorSupport::CreateStreamLoader(
+    java::WebRequest::Param aRequest, int32_t aFlags,
+    java::GeckoResult::Param aResult) {
+  const auto req = java::WebRequest::LocalRef(aRequest);
+  const auto reqBase = java::WebMessage::LocalRef(req.Cast<java::WebMessage>());
+
+  nsCOMPtr<nsIURI> uri;
+  nsresult rv = NS_NewURI(getter_AddRefs(uri), reqBase->Uri()->ToString());
+  NS_ENSURE_SUCCESS(rv, NS_ERROR_MALFORMED_URI);
+
+  nsCOMPtr<nsIChannel> channel;
+  rv = NS_NewChannel(getter_AddRefs(channel), uri,
+                     nsContentUtils::GetSystemPrincipal(),
+                     nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
+                     nsIContentPolicy::TYPE_OTHER);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (aFlags & java::GeckoWebExecutor::FETCH_FLAGS_ANONYMOUS) {
+    channel->SetLoadFlags(nsIRequest::LOAD_ANONYMOUS);
+  }
+
+  bool shouldResistFingerprinting = nsContentUtils::ShouldResistFingerprinting(
+      channel, RFPTarget::IsAlwaysEnabledForPrecompute);
+  nsCOMPtr<nsICookieJarSettings> cookieJarSettings;
+  if (aFlags & java::GeckoWebExecutor::FETCH_FLAGS_PRIVATE) {
+    nsCOMPtr<nsIPrivateBrowsingChannel> pbChannel = do_QueryInterface(channel);
+    NS_ENSURE_TRUE(pbChannel, NS_ERROR_FAILURE);
+    pbChannel->SetPrivate(true);
+    cookieJarSettings = CookieJarSettings::Create(CookieJarSettings::ePrivate,
+                                                  shouldResistFingerprinting);
+  } else {
+    cookieJarSettings = CookieJarSettings::Create(CookieJarSettings::eRegular,
+                                                  shouldResistFingerprinting);
+  }
+  MOZ_ASSERT(cookieJarSettings);
+
+  nsCOMPtr<nsILoadInfo> loadInfo = channel->LoadInfo();
+  loadInfo->SetCookieJarSettings(cookieJarSettings);
+
+  // setup http/https specific things
+  nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(channel, &rv));
+  if (httpChannel) {
+    rv = SetupHttpChannel(httpChannel, channel, aRequest);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // set up the listener
+  const bool allowRedirects =
+      !(aFlags & java::GeckoWebExecutor::FETCH_FLAGS_NO_REDIRECTS);
+  const bool testStreamFailure =
+      (aFlags & java::GeckoWebExecutor::FETCH_FLAGS_STREAM_FAILURE_TEST);
+
+  RefPtr<LoaderListener> listener =
+      new LoaderListener(aResult, allowRedirects, testStreamFailure);
+
+  rv = channel->SetNotificationCallbacks(listener);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Finally, open the channel
+  return channel->AsyncOpen(listener);
+}
+
+void WebExecutorSupport::Fetch(jni::Object::Param aRequest, int32_t aFlags,
+                               jni::Object::Param aResult) {
+  const auto request = java::WebRequest::LocalRef(aRequest);
+  auto result = java::GeckoResult::LocalRef(aResult);
+
+  nsresult rv = CreateStreamLoader(request, aFlags, result);
+  if (NS_FAILED(rv)) {
+    CompleteWithError(result, rv);
+  }
+}
+
+static nsresult ResolveHost(nsCString& host, java::GeckoResult::Param result) {
+  nsresult rv;
+  nsCOMPtr<nsIDNSService> dns = do_GetService(NS_DNSSERVICE_CONTRACTID, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsICancelable> cancelable;
+  RefPtr<DNSListener> listener = new DNSListener(host, result);
+  rv = dns->AsyncResolveNative(host, nsIDNSService::RESOLVE_TYPE_DEFAULT,
+                               nsIDNSService::RESOLVE_DEFAULT_FLAGS, nullptr,
+                               listener, nullptr /* aListenerTarget */,
+                               OriginAttributes(), getter_AddRefs(cancelable));
+  return rv;
+}
+
+void WebExecutorSupport::Resolve(jni::String::Param aUri,
+                                 jni::Object::Param aResult) {
+  auto result = java::GeckoResult::LocalRef(aResult);
+
+  nsCString uri = aUri->ToCString();
+  nsresult rv = ResolveHost(uri, result);
+  if (NS_FAILED(rv)) {
+    java::sdk::UnknownHostException::LocalRef error =
+        java::sdk::UnknownHostException::New();
+    result->CompleteExceptionally(error.Cast<jni::Throwable>());
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/android/WebExecutorSupport.h b/widget/android/WebExecutorSupport.h
new file mode 100644
index 0000000000..65a68fcc40
--- /dev/null
+++ b/widget/android/WebExecutorSupport.h
@@ -0,0 +1,32 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WebExecutorSupport_h__
+#define WebExecutorSupport_h__
+
+#include "mozilla/java/GeckoWebExecutorNatives.h"
+#include "mozilla/java/GeckoResultWrappers.h"
+#include "mozilla/java/WebRequestWrappers.h"
+
+namespace mozilla {
+namespace widget {
+
+class WebExecutorSupport final
+    : public java::GeckoWebExecutor::Natives<WebExecutorSupport> {
+ public:
+  static void Fetch(jni::Object::Param request, int32_t flags,
+                    jni::Object::Param result);
+  static void Resolve(jni::String::Param aUri, jni::Object::Param result);
+
+ protected:
+  static nsresult CreateStreamLoader(java::WebRequest::Param aRequest,
+                                     int32_t aFlags,
+                                     java::GeckoResult::Param aResult);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // WebExecutorSupport_h__
diff --git a/widget/android/WindowEvent.h b/widget/android/WindowEvent.h
new file mode 100644
index 0000000000..fdb73bf692
--- /dev/null
+++ b/widget/android/WindowEvent.h
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_WindowEvent_h
+#define mozilla_widget_WindowEvent_h
+
+#include "nsThreadUtils.h"
+#include "mozilla/jni/Natives.h"
+
+namespace mozilla {
+namespace widget {
+
+// An Event subclass that guards against stale events.
+// (See the implmentation of mozilla::jni::detail::ProxyNativeCall for info
+//  about the default template parameters for this class)
+template <typename Lambda, bool IsStatic = Lambda::isStatic,
+          typename InstanceType = typename Lambda::ThisArgType,
+          class Impl = typename Lambda::TargetClass>
+class WindowEvent : public Runnable {
+  bool IsStaleCall() {
+    if (IsStatic) {
+      // Static calls are never stale.
+      return false;
+    }
+
+    return jni::NativePtrTraits<Impl>::IsStale(mInstance);
+  }
+
+  Lambda mLambda;
+  const InstanceType mInstance;
+
+ public:
+  WindowEvent(Lambda&& aLambda, InstanceType&& aInstance)
+      : Runnable("mozilla::widget::WindowEvent"),
+        mLambda(std::move(aLambda)),
+        mInstance(std::forward<InstanceType>(aInstance)) {}
+
+  explicit WindowEvent(Lambda&& aLambda)
+      : Runnable("mozilla::widget::WindowEvent"),
+        mLambda(std::move(aLambda)),
+        mInstance(mLambda.GetThisArg()) {}
+
+  NS_IMETHOD Run() override {
+    if (!IsStaleCall()) {
+      mLambda();
+    }
+    return NS_OK;
+  }
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_WindowEvent_h
diff --git a/widget/android/bindings/AccessibilityEvent-classes.txt b/widget/android/bindings/AccessibilityEvent-classes.txt
new file mode 100644
index 0000000000..b54e3ce105
--- /dev/null
+++ b/widget/android/bindings/AccessibilityEvent-classes.txt
@@ -0,0 +1,3 @@
+# We only use constants from AccessibilityEvent
+[android.view.accessibility.AccessibilityEvent = skip:true]
+<field> = skip:false
diff --git a/widget/android/bindings/AndroidBuild-classes.txt b/widget/android/bindings/AndroidBuild-classes.txt
new file mode 100644
index 0000000000..a76aa12c66
--- /dev/null
+++ b/widget/android/bindings/AndroidBuild-classes.txt
@@ -0,0 +1,5 @@
+[android.os.Build]
+<field> = noLiteral:true
+
+[android.os.Build$VERSION]
+<field> = noLiteral:true
diff --git a/widget/android/bindings/AndroidDragEvent-classes.txt b/widget/android/bindings/AndroidDragEvent-classes.txt
new file mode 100644
index 0000000000..368f500139
--- /dev/null
+++ b/widget/android/bindings/AndroidDragEvent-classes.txt
@@ -0,0 +1,3 @@
+# We only use constants from DragEvent
+[android.view.DragEvent = skip:true]
+<field> = skip:false
diff --git a/widget/android/bindings/AndroidGraphics-classes.txt b/widget/android/bindings/AndroidGraphics-classes.txt
new file mode 100644
index 0000000000..452ba404e8
--- /dev/null
+++ b/widget/android/bindings/AndroidGraphics-classes.txt
@@ -0,0 +1,10 @@
+[android.graphics.Bitmap = skip:true]
+copyPixelsFromBuffer(Ljava/nio/Buffer;)V =
+createBitmap(IILandroid/graphics/Bitmap$Config;)Landroid/graphics/Bitmap; =
+
+[android.graphics.Bitmap$Config = skip:true]
+valueOf(Ljava/lang/String;)Landroid/graphics/Bitmap$Config; =
+ALPHA_8 =
+ARGB_8888 =
+RGBA_F16 =
+RGB_565 =
\ No newline at end of file
diff --git a/widget/android/bindings/AndroidInputType-classes.txt b/widget/android/bindings/AndroidInputType-classes.txt
new file mode 100644
index 0000000000..fa1138dce4
--- /dev/null
+++ b/widget/android/bindings/AndroidInputType-classes.txt
@@ -0,0 +1,3 @@
+# We only use constants from InputType
+[android.text.InputType = skip:true]
+<field> = skip:false
diff --git a/widget/android/bindings/AndroidProcess-classes.txt b/widget/android/bindings/AndroidProcess-classes.txt
new file mode 100644
index 0000000000..a6929ac5bc
--- /dev/null
+++ b/widget/android/bindings/AndroidProcess-classes.txt
@@ -0,0 +1,5 @@
+[android.os.Process = skip:true]
+setThreadPriority =
+getThreadPriority =
+myTid =
+THREAD_PRIORITY_URGENT_AUDIO =
diff --git a/widget/android/bindings/AndroidRect-classes.txt b/widget/android/bindings/AndroidRect-classes.txt
new file mode 100644
index 0000000000..76d3094a9f
--- /dev/null
+++ b/widget/android/bindings/AndroidRect-classes.txt
@@ -0,0 +1,2 @@
+[android.graphics.Rect]
+[android.graphics.RectF]
diff --git a/widget/android/bindings/InetAddress-classes.txt b/widget/android/bindings/InetAddress-classes.txt
new file mode 100644
index 0000000000..65788be252
--- /dev/null
+++ b/widget/android/bindings/InetAddress-classes.txt
@@ -0,0 +1,6 @@
+# We only want getByAddress(String, byte[])
+[java.net.InetAddress = skip:true]
+getByAddress(Ljava/lang/String;[B)Ljava/net/InetAddress; = skip:false
+
+[java.net.UnknownHostException = skip:true]
+<init>()V =
diff --git a/widget/android/bindings/JavaBuiltins-classes.txt b/widget/android/bindings/JavaBuiltins-classes.txt
new file mode 100644
index 0000000000..c6be5dde34
--- /dev/null
+++ b/widget/android/bindings/JavaBuiltins-classes.txt
@@ -0,0 +1,25 @@
+[java.lang.Boolean = skip:true]
+# Use static fields for boxing boolean.
+TRUE =
+FALSE =
+booleanValue =
+
+[java.lang.Double = skip:true]
+<init>(D)V =
+
+[java.lang.Integer = skip:true]
+# Use valueOf() for boxing int; don't use constructor
+# because some Integer values are cached.
+valueOf(I)Ljava/lang/Integer; =
+
+[java.lang.Long = skip:true]
+valueOf(J)Ljava/lang/Long; =
+
+[java.lang.Number = skip:true]
+# Use doubleValue() for unboxing Double/Float/Long.
+doubleValue =
+# Use intValue() for unboxing Byte/Int/Short.
+intValue =
+
+[java.lang.String = skip:true]
+valueOf(Ljava/lang/Object;)Ljava/lang/String; =
diff --git a/widget/android/bindings/JavaExceptions-classes.txt b/widget/android/bindings/JavaExceptions-classes.txt
new file mode 100644
index 0000000000..ebaff375d5
--- /dev/null
+++ b/widget/android/bindings/JavaExceptions-classes.txt
@@ -0,0 +1,8 @@
+[java.lang.IllegalStateException = skip:true]
+<init>(Ljava/lang/String;)V =
+
+[java.lang.IllegalArgumentException = skip:true]
+<init>(Ljava/lang/String;)V =
+
+[java.lang.Throwable = skip:true]
+getMessage()Ljava/lang/String; =
diff --git a/widget/android/bindings/KeyEvent-classes.txt b/widget/android/bindings/KeyEvent-classes.txt
new file mode 100644
index 0000000000..6001a5025b
--- /dev/null
+++ b/widget/android/bindings/KeyEvent-classes.txt
@@ -0,0 +1,3 @@
+# We only use constants from KeyEvent
+[android.view.KeyEvent = skip:true]
+<field> = skip:false
diff --git a/widget/android/bindings/MediaCodec-classes.txt b/widget/android/bindings/MediaCodec-classes.txt
new file mode 100644
index 0000000000..a68b86e148
--- /dev/null
+++ b/widget/android/bindings/MediaCodec-classes.txt
@@ -0,0 +1,15 @@
+[android.media.MediaCodec = exceptionMode:nsresult]
+[android.media.MediaCodec$BufferInfo = exceptionMode:nsresult]
+[android.media.MediaCodec$CryptoInfo = exceptionMode:nsresult]
+
+# We only use constants from CodecCapabilities
+[android.media.MediaCodecInfo$CodecCapabilities = skip:true]
+<field> = skip:false
+
+# We only use constants from KeyStatus
+[android.media.MediaDrm$KeyStatus = skip:true]
+<field> = skip:false
+[android.media.AudioFormat = skip:true]
+<field> = skip:false
+
+[android.media.MediaFormat = exceptionMode:nsresult]
diff --git a/widget/android/bindings/MotionEvent-classes.txt b/widget/android/bindings/MotionEvent-classes.txt
new file mode 100644
index 0000000000..17874a16af
--- /dev/null
+++ b/widget/android/bindings/MotionEvent-classes.txt
@@ -0,0 +1,3 @@
+# We only use constants from MotionEvent
+[android.view.MotionEvent = skip:true]
+<field> = skip:false
diff --git a/widget/android/bindings/SurfaceTexture-classes.txt b/widget/android/bindings/SurfaceTexture-classes.txt
new file mode 100644
index 0000000000..554c8e7c3f
--- /dev/null
+++ b/widget/android/bindings/SurfaceTexture-classes.txt
@@ -0,0 +1,5 @@
+[android.graphics.SurfaceTexture = exceptionMode:nsresult]
+[android.view.Surface = exceptionMode:nsresult]
+<init>(Landroid/view/SurfaceControl;)V = stubName:FromSurfaceControl, exceptionMode:abort
+[android.view.SurfaceControl = exceptionMode:nsresult]
+isValid()Z = exceptionMode:abort
diff --git a/widget/android/bindings/ViewConfiguration-classes.txt b/widget/android/bindings/ViewConfiguration-classes.txt
new file mode 100644
index 0000000000..cf8689f25a
--- /dev/null
+++ b/widget/android/bindings/ViewConfiguration-classes.txt
@@ -0,0 +1 @@
+[android.view.ViewConfiguration = exceptionMode:nsresult]
diff --git a/widget/android/bindings/moz.build b/widget/android/bindings/moz.build
new file mode 100644
index 0000000000..f3f4d138ff
--- /dev/null
+++ b/widget/android/bindings/moz.build
@@ -0,0 +1,55 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("GeckoView", "General")
+
+# List of stems to generate .cpp and .h files for.  To add a stem, add it to
+# this list and ensure that $(stem)-classes.txt exists in this directory.
+generated = [
+    "AccessibilityEvent",
+    "AndroidBuild",
+    "AndroidDragEvent",
+    "AndroidGraphics",
+    "AndroidInputType",
+    "AndroidProcess",
+    "AndroidRect",
+    "InetAddress",
+    "JavaBuiltins",
+    "JavaExceptions",
+    "KeyEvent",
+    "MediaCodec",
+    "MotionEvent",
+    "SurfaceTexture",
+    "ViewConfiguration",
+]
+
+SOURCES += ["!%s.cpp" % stem for stem in generated]
+
+EXPORTS += ["!%s.h" % stem for stem in generated]
+
+# The recursive make backend treats the first output specially: it's passed as
+# an open FileAvoidWrite to the invoked script.  That doesn't work well with
+# the Gradle task that generates all of the outputs, so we add a dummy first
+# output.
+t = tuple(
+    ["sdk_bindings"]
+    + ["%s.cpp" % stem for stem in generated]
+    + ["%s.h" % stem for stem in generated]
+)
+
+GeneratedFile(
+    *t,
+    script="/mobile/android/gradle.py",
+    entry_point="generate_sdk_bindings",
+    inputs=["%s-classes.txt" % stem for stem in generated]
+)
+
+FINAL_LIBRARY = "xul"
+
+LOCAL_INCLUDES += [
+    "/widget/android",
+]
diff --git a/widget/android/components.conf b/widget/android/components.conf
new file mode 100644
index 0000000000..1c7b49cd38
--- /dev/null
+++ b/widget/android/components.conf
@@ -0,0 +1,109 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Headers = [
+    '/widget/android/nsWidgetFactory.h',
+]
+
+InitFunc = 'nsWidgetAndroidModuleCtor'
+UnloadFunc = 'nsWidgetAndroidModuleDtor'
+
+Classes = [
+    {
+        'cid': '{2d96b3df-c051-11d1-a827-0040959a28c9}',
+        'contract_ids': ['@mozilla.org/widget/appshell/android;1'],
+        'legacy_constructor': 'nsAppShellConstructor',
+        'headers': ['/widget/android/nsWidgetFactory.h'],
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_UTILITY_AND_GMPLUGIN_PROCESS,
+    },
+    {
+        'cid': '{d594094c-28b6-466b-97d7-66c039c3dea9}',
+        'contract_ids': ['@mozilla.org/gfx/parent/screenmanager;1'],
+        'singleton': True,
+        'type': 'mozilla::widget::ScreenManager',
+        'headers': ['mozilla/widget/ScreenManager.h'],
+        'constructor': 'mozilla::widget::ScreenManager::GetAddRefedSingleton',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{6987230e-0098-4e78-bc5f-1493ee7519fa}',
+        'contract_ids': ['@mozilla.org/widget/useridleservice;1'],
+        'singleton': True,
+        'type': 'nsUserIdleServiceAndroid',
+        'headers': ['/widget/android/nsUserIdleServiceAndroid.h'],
+        'constructor': 'nsUserIdleServiceAndroid::GetInstance',
+    },
+    {
+        'cid': '{8b5314bc-db01-11d2-96ce-0060b0fb9956}',
+        'contract_ids': ['@mozilla.org/widget/transferable;1'],
+        'type': 'nsTransferable',
+        'headers': ['/widget/nsTransferable.h'],
+    },
+    {
+        'cid': '{9d5adbb9-1da4-4162-acba-b373fe3ae837}',
+        'contract_ids': ['@mozilla.org/widget/parent/clipboard;1'],
+        'interfaces': ['nsIClipboard'],
+        'type': 'nsClipboard',
+        'headers': ['/widget/android/nsClipboard.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{77221d5a-1dd2-11b2-8c69-c710f15d2ed5}',
+        'contract_ids': ['@mozilla.org/widget/clipboardhelper;1'],
+        'type': 'nsClipboardHelper',
+        'headers': ['/widget/nsClipboardHelper.h'],
+    },
+    {
+        'cid': '{841387c8-72e6-484b-9296-bf6eea80d58a}',
+        'contract_ids': ['@mozilla.org/gfx/printsettings-service;1'],
+        'type': 'nsPrintSettingsServiceAndroid',
+        'headers': ['/widget/android/nsPrintSettingsServiceAndroid.h'],
+        'init_method': 'Init',
+    },
+    {
+        'cid': '{d3f69889-e13a-4321-980c-a39332e21f34}',
+        'contract_ids': ['@mozilla.org/gfx/devicecontextspec;1'],
+        'type': 'nsDeviceContextSpecAndroid',
+        'headers': ['/widget/android/nsDeviceContextAndroid.h'],
+    },
+    {
+        'cid': '{948a0023-e3a7-11d2-96cf-0060b0fb9956}',
+        'contract_ids': ['@mozilla.org/widget/htmlformatconverter;1'],
+        'type': 'nsHTMLFormatConverter',
+        'headers': ['/widget/nsHTMLFormatConverter.h'],
+    },
+    {
+        'name': 'GfxInfo',
+        'cid': '{d755a760-9f27-11df-0800-200c9a664242}',
+        'contract_ids': ['@mozilla.org/gfx/info;1'],
+        'type': 'mozilla::widget::GfxInfo',
+        'headers': ['/widget/android/GfxInfo.h'],
+        'init_method': 'Init',
+    },
+    {
+        'js_name': 'androidBridge',
+        'cid': '{0fe2321d-ebd9-467d-a743-03a68d40599e}',
+        'contract_ids': ['@mozilla.org/android/bridge;1'],
+        'interfaces': ['nsIAndroidBridge'],
+        'type': 'nsAndroidBridge',
+        'headers': ['/widget/android/AndroidBridge.h'],
+    },
+    {
+        'cid': '{84e11f80-ca55-11dd-ad8b-0800200c9a66}',
+        'contract_ids': ['@mozilla.org/system-alerts-service;1'],
+        'type': 'mozilla::widget::AndroidAlerts',
+        'headers': ['/widget/android/AndroidAlerts.h'],
+    },
+    {
+        'cid': '{b1abaf0e-52b2-4e65-aee1-299ea9a74230}',
+        'contract_ids': ['@mozilla.org/widget/parent/dragservice;1'],
+        'singleton': True,
+        'type': 'nsDragService',
+        'headers': ['/widget/android/nsDragService.h'],
+        'constructor': 'nsDragService::GetInstance',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+]
diff --git a/widget/android/jni/Accessors.h b/widget/android/jni/Accessors.h
new file mode 100644
index 0000000000..7496cbcb5a
--- /dev/null
+++ b/widget/android/jni/Accessors.h
@@ -0,0 +1,251 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_jni_Accessors_h__
+#define mozilla_jni_Accessors_h__
+
+#include <jni.h>
+
+#include "mozilla/jni/Refs.h"
+#include "mozilla/jni/Types.h"
+#include "mozilla/jni/Utils.h"
+#include "AndroidBridge.h"
+
+namespace mozilla {
+namespace jni {
+
+namespace detail {
+
+// Helper class to convert an arbitrary type to a jvalue, e.g. Value(123).val.
+struct Value {
+  explicit Value(jboolean z) { val.z = z; }
+  explicit Value(jbyte b) { val.b = b; }
+  explicit Value(jchar c) { val.c = c; }
+  explicit Value(jshort s) { val.s = s; }
+  explicit Value(jint i) { val.i = i; }
+  explicit Value(jlong j) { val.j = j; }
+  explicit Value(jfloat f) { val.f = f; }
+  explicit Value(jdouble d) { val.d = d; }
+  explicit Value(jobject l) { val.l = l; }
+
+  jvalue val;
+};
+
+}  // namespace detail
+
+using namespace detail;
+
+// Base class for Method<>, Field<>, and Constructor<>.
+class Accessor {
+  static void GetNsresult(JNIEnv* env, nsresult* rv) {
+    if (env->ExceptionCheck()) {
+#ifdef MOZ_CHECK_JNI
+      env->ExceptionDescribe();
+#endif
+      env->ExceptionClear();
+      *rv = NS_ERROR_FAILURE;
+    } else {
+      *rv = NS_OK;
+    }
+  }
+
+ protected:
+  // Called after making a JNIEnv call.
+  template <class Traits>
+  static void EndAccess(const typename Traits::Owner::Context& ctx,
+                        nsresult* rv) {
+    if (Traits::exceptionMode == ExceptionMode::ABORT) {
+      MOZ_CATCH_JNI_EXCEPTION(ctx.Env());
+
+    } else if (Traits::exceptionMode == ExceptionMode::NSRESULT) {
+      GetNsresult(ctx.Env(), rv);
+    }
+  }
+};
+
+// Member<> is used to call a JNI method given a traits class.
+template <class Traits, typename ReturnType = typename Traits::ReturnType>
+class Method : public Accessor {
+  typedef Accessor Base;
+  typedef typename Traits::Owner::Context Context;
+
+ protected:
+  static jmethodID sID;
+
+  static void BeginAccess(const Context& ctx) {
+    MOZ_ASSERT_JNI_THREAD(Traits::callingThread);
+    static_assert(Traits::dispatchTarget == DispatchTarget::CURRENT,
+                  "Dispatching not supported for method call");
+
+    if (sID) {
+      return;
+    }
+
+    if (Traits::isStatic) {
+      MOZ_ALWAYS_TRUE(
+          sID = AndroidBridge::GetStaticMethodID(
+              ctx.Env(), ctx.ClassRef(), Traits::name, Traits::signature));
+    } else {
+      MOZ_ALWAYS_TRUE(
+          sID = AndroidBridge::GetMethodID(ctx.Env(), ctx.ClassRef(),
+                                           Traits::name, Traits::signature));
+    }
+  }
+
+  static void EndAccess(const Context& ctx, nsresult* rv) {
+    return Base::EndAccess<Traits>(ctx, rv);
+  }
+
+ public:
+  template <typename... Args>
+  static ReturnType Call(const Context& ctx, nsresult* rv,
+                         const Args&... args) {
+    JNIEnv* const env = ctx.Env();
+    BeginAccess(ctx);
+
+    jvalue jargs[] = {Value(TypeAdapter<Args>::FromNative(env, args)).val...};
+
+    auto result = TypeAdapter<ReturnType>::ToNative(
+        env, Traits::isStatic ? (env->*TypeAdapter<ReturnType>::StaticCall)(
+                                    ctx.ClassRef(), sID, jargs)
+                              : (env->*TypeAdapter<ReturnType>::Call)(
+                                    ctx.Get(), sID, jargs));
+
+    EndAccess(ctx, rv);
+    return result;
+  }
+};
+
+// Define sID member.
+template <class T, typename R>
+jmethodID Method<T, R>::sID;
+
+// Specialize void because C++ forbids us from
+// using a "void" temporary result variable.
+template <class Traits>
+class Method<Traits, void> : public Method<Traits, bool> {
+  typedef Method<Traits, bool> Base;
+  typedef typename Traits::Owner::Context Context;
+
+ public:
+  template <typename... Args>
+  static void Call(const Context& ctx, nsresult* rv, const Args&... args) {
+    JNIEnv* const env = ctx.Env();
+    Base::BeginAccess(ctx);
+
+    jvalue jargs[] = {Value(TypeAdapter<Args>::FromNative(env, args)).val...};
+
+    if (Traits::isStatic) {
+      env->CallStaticVoidMethodA(ctx.ClassRef(), Base::sID, jargs);
+    } else {
+      env->CallVoidMethodA(ctx.Get(), Base::sID, jargs);
+    }
+
+    Base::EndAccess(ctx, rv);
+  }
+};
+
+// Constructor<> is used to construct a JNI instance given a traits class.
+template <class Traits>
+class Constructor : protected Method<Traits, typename Traits::ReturnType> {
+  typedef typename Traits::Owner::Context Context;
+  typedef typename Traits::ReturnType ReturnType;
+  typedef Method<Traits, ReturnType> Base;
+
+ public:
+  template <typename... Args>
+  static ReturnType Call(const Context& ctx, nsresult* rv,
+                         const Args&... args) {
+    JNIEnv* const env = ctx.Env();
+    Base::BeginAccess(ctx);
+
+    jvalue jargs[] = {Value(TypeAdapter<Args>::FromNative(env, args)).val...};
+
+    auto result = TypeAdapter<ReturnType>::ToNative(
+        env, env->NewObjectA(ctx.ClassRef(), Base::sID, jargs));
+
+    Base::EndAccess(ctx, rv);
+    return result;
+  }
+};
+
+// Field<> is used to access a JNI field given a traits class.
+template <class Traits>
+class Field : public Accessor {
+  typedef Accessor Base;
+  typedef typename Traits::Owner::Context Context;
+  typedef typename Traits::ReturnType GetterType;
+  typedef typename Traits::SetterType SetterType;
+
+ private:
+  static jfieldID sID;
+
+  static void BeginAccess(const Context& ctx) {
+    MOZ_ASSERT_JNI_THREAD(Traits::callingThread);
+    static_assert(Traits::dispatchTarget == DispatchTarget::CURRENT,
+                  "Dispatching not supported for field access");
+
+    if (sID) {
+      return;
+    }
+
+    if (Traits::isStatic) {
+      MOZ_ALWAYS_TRUE(
+          sID = AndroidBridge::GetStaticFieldID(
+              ctx.Env(), ctx.ClassRef(), Traits::name, Traits::signature));
+    } else {
+      MOZ_ALWAYS_TRUE(sID = AndroidBridge::GetFieldID(ctx.Env(), ctx.ClassRef(),
+                                                      Traits::name,
+                                                      Traits::signature));
+    }
+  }
+
+  static void EndAccess(const Context& ctx, nsresult* rv) {
+    return Base::EndAccess<Traits>(ctx, rv);
+  }
+
+ public:
+  static GetterType Get(const Context& ctx, nsresult* rv) {
+    JNIEnv* const env = ctx.Env();
+    BeginAccess(ctx);
+
+    auto result = TypeAdapter<GetterType>::ToNative(
+        env, Traits::isStatic
+                 ?
+
+                 (env->*TypeAdapter<GetterType>::StaticGet)(ctx.ClassRef(), sID)
+                 :
+
+                 (env->*TypeAdapter<GetterType>::Get)(ctx.Get(), sID));
+
+    EndAccess(ctx, rv);
+    return result;
+  }
+
+  static void Set(const Context& ctx, nsresult* rv, SetterType val) {
+    JNIEnv* const env = ctx.Env();
+    BeginAccess(ctx);
+
+    if (Traits::isStatic) {
+      (env->*TypeAdapter<SetterType>::StaticSet)(
+          ctx.ClassRef(), sID, TypeAdapter<SetterType>::FromNative(env, val));
+    } else {
+      (env->*TypeAdapter<SetterType>::Set)(
+          ctx.Get(), sID, TypeAdapter<SetterType>::FromNative(env, val));
+    }
+
+    EndAccess(ctx, rv);
+  }
+};
+
+// Define sID member.
+template <class T>
+jfieldID Field<T>::sID;
+
+}  // namespace jni
+}  // namespace mozilla
+
+#endif  // mozilla_jni_Accessors_h__
diff --git a/widget/android/jni/Conversions.cpp b/widget/android/jni/Conversions.cpp
new file mode 100644
index 0000000000..f7742b9535
--- /dev/null
+++ b/widget/android/jni/Conversions.cpp
@@ -0,0 +1,115 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Conversions.h"
+#include "JavaBuiltins.h"
+
+#include "mozilla/ipc/GeckoChildProcessHost.h"
+
+namespace mozilla {
+namespace jni {
+
+template <class T>
+jfieldID GetValueFieldID(JNIEnv* aEnv, const char* aType) {
+  const jfieldID id = aEnv->GetFieldID(
+      typename T::Context(aEnv, nullptr).ClassRef(), "value", aType);
+  aEnv->ExceptionClear();
+  return id;
+}
+
+// Cached locations of the primitive types within their standard boxed objects
+// to skip doing that lookup on every get.
+static jfieldID gBooleanValueField;
+static jfieldID gIntValueField;
+static jfieldID gDoubleValueField;
+
+void InitConversionStatics() {
+  MOZ_ASSERT(NS_IsMainThread());
+  JNIEnv* const env = jni::GetGeckoThreadEnv();
+  gBooleanValueField = GetValueFieldID<java::sdk::Boolean>(env, "Z");
+  gIntValueField = GetValueFieldID<java::sdk::Integer>(env, "I");
+  gDoubleValueField = GetValueFieldID<java::sdk::Double>(env, "D");
+}
+
+template <>
+bool Java2Native(mozilla::jni::Object::Param aData, JNIEnv* aEnv) {
+  MOZ_ASSERT(aData.IsInstanceOf<jni::Boolean>());
+
+  bool result = false;
+  if (gBooleanValueField) {
+    if (!aEnv) {
+      aEnv = jni::GetEnvForThread();
+    }
+    result =
+        aEnv->GetBooleanField(aData.Get(), gBooleanValueField) != JNI_FALSE;
+    MOZ_CATCH_JNI_EXCEPTION(aEnv);
+  } else {
+    result = java::sdk::Boolean::Ref::From(aData)->BooleanValue();
+  }
+
+  return result;
+}
+
+template <>
+int Java2Native(mozilla::jni::Object::Param aData, JNIEnv* aEnv) {
+  MOZ_ASSERT(aData.IsInstanceOf<jni::Integer>());
+
+  int result = 0;
+  if (gIntValueField) {
+    if (!aEnv) {
+      aEnv = jni::GetEnvForThread();
+    }
+    result = aEnv->GetIntField(aData.Get(), gIntValueField);
+    MOZ_CATCH_JNI_EXCEPTION(aEnv);
+  } else {
+    result = java::sdk::Number::Ref::From(aData)->IntValue();
+  }
+
+  return result;
+}
+
+template <>
+double Java2Native(mozilla::jni::Object::Param aData, JNIEnv* aEnv) {
+  MOZ_ASSERT(aData.IsInstanceOf<jni::Double>());
+
+  double result = 0;
+  if (gDoubleValueField) {
+    if (!aEnv) {
+      aEnv = jni::GetEnvForThread();
+    }
+    result = aEnv->GetDoubleField(aData.Get(), gDoubleValueField);
+    MOZ_CATCH_JNI_EXCEPTION(aEnv);
+  } else {
+    result = java::sdk::Number::Ref::From(aData)->DoubleValue();
+  }
+
+  return result;
+}
+
+template <>
+ipc::LaunchError Java2Native(mozilla::jni::Object::Param aData, JNIEnv* aEnv) {
+  // Bug 1819311: there is not much we can really catch due to how Android
+  // services are started, so for now we just expose it this way.
+  return ipc::LaunchError("Java2Native");
+}
+
+template <>
+nsString Java2Native(mozilla::jni::Object::Param aData, JNIEnv* aEnv) {
+  nsString result;
+  if (aData != NULL && aData.IsInstanceOf<jni::String>()) {
+    result = jni::String::Ref::From(aData)->ToString();
+  }
+  return result;
+}
+
+template <>
+nsresult Java2Native(mozilla::jni::Object::Param aData, JNIEnv* aEnv) {
+  MOZ_ASSERT(aData.IsInstanceOf<jni::Throwable>());
+  return NS_ERROR_FAILURE;
+}
+
+}  // namespace jni
+}  // namespace mozilla
diff --git a/widget/android/jni/Conversions.h b/widget/android/jni/Conversions.h
new file mode 100644
index 0000000000..1d9e20acc7
--- /dev/null
+++ b/widget/android/jni/Conversions.h
@@ -0,0 +1,23 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_jni_Conversions_h__
+#define mozilla_jni_Conversions_h__
+
+#include "mozilla/jni/Refs.h"
+
+namespace mozilla {
+namespace jni {
+
+template <typename ArgType>
+ArgType Java2Native(mozilla::jni::Object::Param, JNIEnv* aEnv = nullptr);
+
+void InitConversionStatics();
+
+}  // namespace jni
+}  // namespace mozilla
+
+#endif  // mozilla_jni_Conversions_h__
diff --git a/widget/android/jni/GeckoBundleUtils.cpp b/widget/android/jni/GeckoBundleUtils.cpp
new file mode 100644
index 0000000000..310f284093
--- /dev/null
+++ b/widget/android/jni/GeckoBundleUtils.cpp
@@ -0,0 +1,309 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/jni/GeckoBundleUtils.h"
+
+#include "JavaBuiltins.h"
+#include "js/Warnings.h"
+#include "nsJSUtils.h"
+
+#include "js/Array.h"
+#include "js/experimental/TypedData.h"
+
+namespace mozilla::jni {
+namespace detail {
+bool CheckJS(JSContext* aCx, bool aResult) {
+  if (!aResult) {
+    JS_ClearPendingException(aCx);
+  }
+  return aResult;
+}
+
+nsresult BoxString(JSContext* aCx, JS::Handle<JS::Value> aData,
+                   jni::Object::LocalRef& aOut) {
+  if (aData.isNullOrUndefined()) {
+    aOut = nullptr;
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(aData.isString());
+
+  JS::Rooted<JSString*> str(aCx, aData.toString());
+
+  if (JS::StringHasLatin1Chars(str)) {
+    nsAutoJSString autoStr;
+    NS_ENSURE_TRUE(CheckJS(aCx, autoStr.init(aCx, str)), NS_ERROR_FAILURE);
+
+    // StringParam can automatically convert a nsString to jstring.
+    aOut = jni::StringParam(autoStr, aOut.Env(), fallible);
+    if (!aOut) {
+      return NS_ERROR_FAILURE;
+    }
+    return NS_OK;
+  }
+
+  // Two-byte string
+  JNIEnv* const env = aOut.Env();
+  const char16_t* chars;
+  {
+    JS::AutoCheckCannotGC nogc;
+    size_t len = 0;
+    chars = JS_GetTwoByteStringCharsAndLength(aCx, nogc, str, &len);
+    if (chars) {
+      aOut = jni::String::LocalRef::Adopt(
+          env, env->NewString(reinterpret_cast<const jchar*>(chars), len));
+    }
+  }
+  if (NS_WARN_IF(!CheckJS(aCx, !!chars) || !aOut)) {
+    env->ExceptionClear();
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+nsresult BoxObject(JSContext* aCx, JS::Handle<JS::Value> aData,
+                   jni::Object::LocalRef& aOut);
+
+template <typename Type, bool (JS::Value::*IsType)() const,
+          Type (JS::Value::*ToType)() const, class ArrayType,
+          typename ArrayType::LocalRef (*NewArray)(const Type*, size_t)>
+nsresult BoxArrayPrimitive(JSContext* aCx, JS::Handle<JSObject*> aData,
+                           jni::Object::LocalRef& aOut, size_t aLength,
+                           JS::Handle<JS::Value> aElement) {
+  JS::Rooted<JS::Value> element(aCx);
+  auto data = MakeUnique<Type[]>(aLength);
+  data[0] = (aElement.get().*ToType)();
+
+  for (size_t i = 1; i < aLength; i++) {
+    NS_ENSURE_TRUE(CheckJS(aCx, JS_GetElement(aCx, aData, i, &element)),
+                   NS_ERROR_FAILURE);
+    NS_ENSURE_TRUE((element.get().*IsType)(), NS_ERROR_INVALID_ARG);
+
+    data[i] = (element.get().*ToType)();
+  }
+  aOut = (*NewArray)(data.get(), aLength);
+  return NS_OK;
+}
+
+nsresult BoxByteArray(JSContext* aCx, JS::Handle<JSObject*> aData,
+                      jni::Object::LocalRef& aOut) {
+  JS::AutoCheckCannotGC nogc;
+  bool isShared = false;
+  const void* data = JS_GetArrayBufferViewData(aData, &isShared, nogc);
+  size_t length = JS_GetArrayBufferViewByteLength(aData);
+
+  aOut = jni::ByteArray::New(reinterpret_cast<const int8_t*>(data), length);
+  if (!aOut) {
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+template <class Type,
+          nsresult (*Box)(JSContext*, JS::Handle<JS::Value>,
+                          jni::Object::LocalRef&),
+          typename IsType>
+nsresult BoxArrayObject(JSContext* aCx, JS::Handle<JSObject*> aData,
+                        jni::Object::LocalRef& aOut, size_t aLength,
+                        JS::Handle<JS::Value> aElement, IsType&& aIsType) {
+  auto out = jni::ObjectArray::New<Type>(aLength);
+  JS::Rooted<JS::Value> element(aCx);
+  jni::Object::LocalRef jniElement(aOut.Env());
+
+  nsresult rv = (*Box)(aCx, aElement, jniElement);
+  NS_ENSURE_SUCCESS(rv, rv);
+  out->SetElement(0, jniElement);
+
+  for (size_t i = 1; i < aLength; i++) {
+    NS_ENSURE_TRUE(CheckJS(aCx, JS_GetElement(aCx, aData, i, &element)),
+                   NS_ERROR_FAILURE);
+    NS_ENSURE_TRUE(element.isNullOrUndefined() || aIsType(element),
+                   NS_ERROR_INVALID_ARG);
+
+    rv = (*Box)(aCx, element, jniElement);
+    NS_ENSURE_SUCCESS(rv, rv);
+    out->SetElement(i, jniElement);
+  }
+  aOut = out;
+  return NS_OK;
+}
+
+nsresult BoxArray(JSContext* aCx, JS::Handle<JSObject*> aData,
+                  jni::Object::LocalRef& aOut) {
+  uint32_t length = 0;
+  NS_ENSURE_TRUE(CheckJS(aCx, JS::GetArrayLength(aCx, aData, &length)),
+                 NS_ERROR_FAILURE);
+
+  if (!length) {
+    // Always represent empty arrays as an empty boolean array.
+    aOut = java::GeckoBundle::EMPTY_BOOLEAN_ARRAY();
+    return NS_OK;
+  }
+
+  // We only check the first element's type. If the array has mixed types,
+  // we'll throw an error during actual conversion.
+  JS::Rooted<JS::Value> element(aCx);
+  NS_ENSURE_TRUE(CheckJS(aCx, JS_GetElement(aCx, aData, 0, &element)),
+                 NS_ERROR_FAILURE);
+
+  if (element.isBoolean()) {
+    return BoxArrayPrimitive<bool, &JS::Value::isBoolean, &JS::Value::toBoolean,
+                             jni::BooleanArray, &jni::BooleanArray::New>(
+        aCx, aData, aOut, length, element);
+  }
+
+  if (element.isInt32()) {
+    nsresult rv =
+        BoxArrayPrimitive<int32_t, &JS::Value::isInt32, &JS::Value::toInt32,
+                          jni::IntArray, &jni::IntArray::New>(aCx, aData, aOut,
+                                                              length, element);
+    if (rv != NS_ERROR_INVALID_ARG) {
+      return rv;
+    }
+    // Not int32, but we can still try a double array.
+  }
+
+  if (element.isNumber()) {
+    return BoxArrayPrimitive<double, &JS::Value::isNumber, &JS::Value::toNumber,
+                             jni::DoubleArray, &jni::DoubleArray::New>(
+        aCx, aData, aOut, length, element);
+  }
+
+  if (element.isNullOrUndefined() || element.isString()) {
+    const auto isString = [](JS::Handle<JS::Value> val) -> bool {
+      return val.isString();
+    };
+    nsresult rv = BoxArrayObject<jni::String, &BoxString>(
+        aCx, aData, aOut, length, element, isString);
+    if (element.isString() || rv != NS_ERROR_INVALID_ARG) {
+      return rv;
+    }
+    // First element was null/undefined, so it may still be an object array.
+  }
+
+  const auto isObject = [aCx](JS::Handle<JS::Value> val) -> bool {
+    if (!val.isObject()) {
+      return false;
+    }
+    bool array = false;
+    JS::Rooted<JSObject*> obj(aCx, &val.toObject());
+    // We don't support array of arrays.
+    return CheckJS(aCx, JS::IsArrayObject(aCx, obj, &array)) && !array;
+  };
+
+  if (element.isNullOrUndefined() || isObject(element)) {
+    return BoxArrayObject<java::GeckoBundle, &BoxObject>(
+        aCx, aData, aOut, length, element, isObject);
+  }
+
+  NS_WARNING("Unknown type");
+  return NS_ERROR_INVALID_ARG;
+}
+
+nsresult BoxValue(JSContext* aCx, JS::Handle<JS::Value> aData,
+                  jni::Object::LocalRef& aOut);
+
+nsresult BoxObject(JSContext* aCx, JS::Handle<JS::Value> aData,
+                   jni::Object::LocalRef& aOut) {
+  if (aData.isNullOrUndefined()) {
+    aOut = nullptr;
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(aData.isObject());
+
+  JS::Rooted<JS::IdVector> ids(aCx, JS::IdVector(aCx));
+  JS::Rooted<JSObject*> obj(aCx, &aData.toObject());
+
+  bool isArray = false;
+  if (CheckJS(aCx, JS::IsArrayObject(aCx, obj, &isArray)) && isArray) {
+    return BoxArray(aCx, obj, aOut);
+  }
+
+  if (JS_IsTypedArrayObject(obj)) {
+    return BoxByteArray(aCx, obj, aOut);
+  }
+
+  NS_ENSURE_TRUE(CheckJS(aCx, JS_Enumerate(aCx, obj, &ids)), NS_ERROR_FAILURE);
+
+  const size_t length = ids.length();
+  auto keys = jni::ObjectArray::New<jni::String>(length);
+  auto values = jni::ObjectArray::New<jni::Object>(length);
+
+  // Iterate through each property of the JS object.
+  for (size_t i = 0; i < ids.length(); i++) {
+    const JS::RootedId id(aCx, ids[i]);
+    JS::Rooted<JS::Value> idVal(aCx);
+    JS::Rooted<JS::Value> val(aCx);
+    jni::Object::LocalRef key(aOut.Env());
+    jni::Object::LocalRef value(aOut.Env());
+
+    NS_ENSURE_TRUE(CheckJS(aCx, JS_IdToValue(aCx, id, &idVal)),
+                   NS_ERROR_FAILURE);
+
+    JS::Rooted<JSString*> idStr(aCx, JS::ToString(aCx, idVal));
+    NS_ENSURE_TRUE(CheckJS(aCx, !!idStr), NS_ERROR_FAILURE);
+
+    idVal.setString(idStr);
+    NS_ENSURE_SUCCESS(BoxString(aCx, idVal, key), NS_ERROR_FAILURE);
+    NS_ENSURE_TRUE(CheckJS(aCx, JS_GetPropertyById(aCx, obj, id, &val)),
+                   NS_ERROR_FAILURE);
+
+    nsresult rv = BoxValue(aCx, val, value);
+    if (rv == NS_ERROR_INVALID_ARG && !JS_IsExceptionPending(aCx)) {
+      nsAutoJSString autoStr;
+      if (CheckJS(aCx, autoStr.init(aCx, idVal.toString()))) {
+        JS_ReportErrorUTF8(aCx, "Invalid event data property %s",
+                           NS_ConvertUTF16toUTF8(autoStr).get());
+      }
+    }
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    keys->SetElement(i, key);
+    values->SetElement(i, value);
+  }
+
+  aOut = java::GeckoBundle::New(keys, values);
+  return NS_OK;
+}
+
+nsresult BoxValue(JSContext* aCx, JS::Handle<JS::Value> aData,
+                  jni::Object::LocalRef& aOut) {
+  if (aData.isNullOrUndefined()) {
+    aOut = nullptr;
+  } else if (aData.isBoolean()) {
+    aOut = aData.toBoolean() ? java::sdk::Boolean::TRUE()
+                             : java::sdk::Boolean::FALSE();
+  } else if (aData.isInt32()) {
+    aOut = java::sdk::Integer::ValueOf(aData.toInt32());
+  } else if (aData.isNumber()) {
+    aOut = java::sdk::Double::New(aData.toNumber());
+  } else if (aData.isString()) {
+    return BoxString(aCx, aData, aOut);
+  } else if (aData.isObject()) {
+    return BoxObject(aCx, aData, aOut);
+  } else {
+    NS_WARNING("Unknown type");
+    return NS_ERROR_INVALID_ARG;
+  }
+  return NS_OK;
+}
+
+}  // namespace detail
+
+nsresult BoxData(JSContext* aCx, JS::Handle<JS::Value> aData,
+                 jni::Object::LocalRef& aOut, bool aObjectOnly) {
+  nsresult rv = NS_ERROR_INVALID_ARG;
+
+  if (!aObjectOnly) {
+    rv = detail::BoxValue(aCx, aData, aOut);
+  } else if (aData.isObject() || aData.isNullOrUndefined()) {
+    rv = detail::BoxObject(aCx, aData, aOut);
+  }
+
+  return rv;
+}
+}  // namespace mozilla::jni
diff --git a/widget/android/jni/GeckoBundleUtils.h b/widget/android/jni/GeckoBundleUtils.h
new file mode 100644
index 0000000000..a92a27abc3
--- /dev/null
+++ b/widget/android/jni/GeckoBundleUtils.h
@@ -0,0 +1,46 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_jni_GeckoBundleUtils_h
+#define mozilla_jni_GeckoBundleUtils_h
+
+#include "mozilla/java/GeckoBundleWrappers.h"
+
+#include "jsapi.h"
+
+namespace mozilla {
+namespace jni {
+
+#define GECKOBUNDLE_START(name)                   \
+  nsTArray<jni::String::LocalRef> _##name##_keys; \
+  nsTArray<jni::Object::LocalRef> _##name##_values;
+
+#define GECKOBUNDLE_PUT(name, key, value)                     \
+  _##name##_keys.AppendElement(                               \
+      jni::StringParam(NS_LITERAL_STRING_FROM_CSTRING(key))); \
+  _##name##_values.AppendElement(value);
+
+#define GECKOBUNDLE_FINISH(name)                                            \
+  MOZ_ASSERT(_##name##_keys.Length() == _##name##_values.Length());         \
+  auto _##name##_jkeys =                                                    \
+      jni::ObjectArray::New<jni::String>(_##name##_keys.Length());          \
+  auto _##name##_jvalues =                                                  \
+      jni::ObjectArray::New<jni::Object>(_##name##_values.Length());        \
+  for (size_t i = 0;                                                        \
+       i < _##name##_keys.Length() && i < _##name##_values.Length(); i++) { \
+    _##name##_jkeys->SetElement(i, _##name##_keys.ElementAt(i));            \
+    _##name##_jvalues->SetElement(i, _##name##_values.ElementAt(i));        \
+  }                                                                         \
+  auto name =                                                               \
+      mozilla::java::GeckoBundle::New(_##name##_jkeys, _##name##_jvalues);
+
+nsresult BoxData(JSContext* aCx, JS::Handle<JS::Value> aData,
+                 jni::Object::LocalRef& aOut, bool aObjectOnly);
+
+}  // namespace jni
+}  // namespace mozilla
+
+#endif  // mozilla_jni_GeckoBundleUtils_h
diff --git a/widget/android/jni/GeckoResultUtils.h b/widget/android/jni/GeckoResultUtils.h
new file mode 100644
index 0000000000..da103f35ee
--- /dev/null
+++ b/widget/android/jni/GeckoResultUtils.h
@@ -0,0 +1,54 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_jni_GeckoResultUtils_h
+#define mozilla_jni_GeckoResultUtils_h
+
+#include "mozilla/java/GeckoResultNatives.h"
+#include "mozilla/jni/Conversions.h"
+
+namespace mozilla {
+namespace jni {
+
+// C++-side object bound to Java's GeckoResult.GeckoCallback.
+//
+// Note that we can't template this class because that breaks JNI dispatch
+// (surprisingly: it compiles, but selects the wrong method specialization
+// during dispatch). So instead we use a templated factory function, which
+// bundles the per-ArgType conversion logic into the callback.
+class GeckoResultCallback final
+    : public java::GeckoResult::GeckoCallback::Natives<GeckoResultCallback> {
+ public:
+  typedef java::GeckoResult::GeckoCallback::Natives<GeckoResultCallback> Base;
+  typedef std::function<void(mozilla::jni::Object::Param)> OuterCallback;
+
+  void Call(mozilla::jni::Object::Param aArg) { mCallback(aArg); }
+
+  template <typename ArgType>
+  static java::GeckoResult::GeckoCallback::LocalRef CreateAndAttach(
+      std::function<void(ArgType)>&& aInnerCallback) {
+    auto java = java::GeckoResult::GeckoCallback::New();
+    OuterCallback outerCallback =
+        [inner{std::move(aInnerCallback)}](mozilla::jni::Object::Param aParam) {
+          ArgType converted = Java2Native<ArgType>(aParam);
+          inner(std::move(converted));
+        };
+    auto native = MakeUnique<GeckoResultCallback>(std::move(outerCallback));
+    Base::AttachNative(java, std::move(native));
+    return java;
+  }
+
+  explicit GeckoResultCallback(OuterCallback&& aCallback)
+      : mCallback(std::move(aCallback)) {}
+
+ private:
+  OuterCallback mCallback;
+};
+
+}  // namespace jni
+}  // namespace mozilla
+
+#endif  // mozilla_jni_GeckoResultUtils_h
diff --git a/widget/android/jni/Natives.h b/widget/android/jni/Natives.h
new file mode 100644
index 0000000000..45b351ba21
--- /dev/null
+++ b/widget/android/jni/Natives.h
@@ -0,0 +1,1540 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_jni_Natives_h__
+#define mozilla_jni_Natives_h__
+
+#include <jni.h>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/RWLock.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Unused.h"
+#include "mozilla/WeakPtr.h"
+#include "mozilla/jni/Accessors.h"
+#include "mozilla/jni/Refs.h"
+#include "mozilla/jni/Types.h"
+#include "mozilla/jni/Utils.h"
+#include "nsThreadUtils.h"
+
+#if defined(_MSC_VER)  // MSVC
+#  define FUNCTION_SIGNATURE __FUNCSIG__
+#elif defined(__GNUC__)  // GCC, Clang
+#  define FUNCTION_SIGNATURE __PRETTY_FUNCTION__
+#endif
+
+struct NativeException {
+  const char* str;
+};
+
+template <class T>
+static NativeException NullHandle() {
+  return {FUNCTION_SIGNATURE};
+}
+
+template <class T>
+static NativeException NullWeakPtr() {
+  return {FUNCTION_SIGNATURE};
+}
+
+namespace mozilla {
+
+template <typename ResolveValueT, typename RejectValueT, bool IsExclusive>
+class MozPromise;
+
+namespace jni {
+
+/**
+ * C++ classes implementing instance (non-static) native methods can choose
+ * from one of two ownership models, when associating a C++ object with a Java
+ * instance.
+ *
+ * * If the C++ class inherits from mozilla::SupportsWeakPtr, weak pointers
+ *   will be used. The Java instance will store and own the pointer to a
+ *   WeakPtr object. The C++ class itself is otherwise not owned or directly
+ *   referenced. Note that mozilla::SupportsWeakPtr only supports being used on
+ *   a single thread. To attach a Java instance to a C++ instance, pass in a
+ *   mozilla::SupportsWeakPtr pointer to the C++ class (i.e. MyClass*).
+ *
+ *   class MyClass : public SupportsWeakPtr
+ *                 , public MyJavaClass::Natives<MyClass>
+ *   {
+ *       // ...
+ *
+ *   public:
+ *       using MyJavaClass::Natives<MyClass>::DisposeNative;
+ *
+ *       void AttachTo(const MyJavaClass::LocalRef& instance)
+ *       {
+ *           MyJavaClass::Natives<MyClass>::AttachNative(
+ *                   instance, static_cast<SupportsWeakPtr*>(this));
+ *
+ *           // "instance" does NOT own "this", so the C++ object
+ *           // lifetime is separate from the Java object lifetime.
+ *       }
+ *   };
+ *
+ * * If the C++ class contains public members AddRef() and Release(), the Java
+ *   instance will store and own the pointer to a RefPtr object, which holds a
+ *   strong reference on the C++ instance. Normal ref-counting considerations
+ *   apply in this case; for example, disposing may cause the C++ instance to
+ *   be deleted and the destructor to be run on the current thread, which may
+ *   not be desirable. To attach a Java instance to a C++ instance, pass in a
+ *   pointer to the C++ class (i.e. MyClass*).
+ *
+ *   class MyClass : public RefCounted<MyClass>
+ *                 , public MyJavaClass::Natives<MyClass>
+ *   {
+ *       // ...
+ *
+ *   public:
+ *       using MyJavaClass::Natives<MyClass>::DisposeNative;
+ *
+ *       void AttachTo(const MyJavaClass::LocalRef& instance)
+ *       {
+ *           MyJavaClass::Natives<MyClass>::AttachNative(instance, this);
+ *
+ *           // "instance" owns "this" through the RefPtr, so the C++ object
+ *           // may be destroyed as soon as instance.disposeNative() is called.
+ *       }
+ *   };
+ *
+ * * In other cases, the Java instance will store and own a pointer to the C++
+ *   object itself. This pointer must not be stored or deleted elsewhere. To
+ *   attach a Java instance to a C++ instance, pass in a reference to a
+ *   UniquePtr of the C++ class (i.e. UniquePtr<MyClass>).
+ *
+ *   class MyClass : public MyJavaClass::Natives<MyClass>
+ *   {
+ *       // ...
+ *
+ *   public:
+ *       using MyJavaClass::Natives<MyClass>::DisposeNative;
+ *
+ *       static void AttachTo(const MyJavaClass::LocalRef& instance)
+ *       {
+ *           MyJavaClass::Natives<MyClass>::AttachNative(
+ *                   instance, mozilla::MakeUnique<MyClass>());
+ *
+ *           // "instance" owns the newly created C++ object, so the C++
+ *           // object is destroyed as soon as instance.disposeNative() is
+ *           // called.
+ *       }
+ *   };
+ */
+
+namespace detail {
+
+/**
+ * Type trait that determines whether a given class has a member named
+ * T::OnWeakNonIntrusiveDetach.
+ *
+ * Example usage:
+ * class Foo {};
+ * class Bar {
+ *  public:
+ *   void OnWeakNonIntrusiveDetach(already_AddRefed<nsIRunnable> aRunnable);
+ * };
+ *
+ * constexpr bool foo = HasWeakNonIntrusiveDetach<Foo>::value; // Expect false
+ * constexpr bool bar = HasWeakNonIntrusiveDetach<Bar>::value; // Expect true
+ */
+template <typename, typename = std::void_t<>>
+struct HasWeakNonIntrusiveDetach : std::false_type {};
+
+template <typename T>
+struct HasWeakNonIntrusiveDetach<
+    T, std::void_t<decltype(std::declval<T>().OnWeakNonIntrusiveDetach(
+           std::declval<already_AddRefed<nsIRunnable>>()))>> : std::true_type {
+};
+
+/**
+ * Type trait that determines whether a given class is refcounted, ie. it has
+ * both T::AddRef and T::Release methods.
+ *
+ * Example usage:
+ * class Foo {};
+ * class Bar {
+ *  public:
+ *   void AddRef();
+ *   void Release();
+ * };
+ *
+ * constexpr bool foo = IsRefCounted<Foo>::value; // Expect false
+ * constexpr bool bar = IsRefCounted<Bar>::value; // Expect true
+ */
+template <typename, typename = std::void_t<>>
+struct IsRefCounted : std::false_type {};
+
+template <typename T>
+struct IsRefCounted<T, std::void_t<decltype(std::declval<T>().AddRef(),
+                                            std::declval<T>().Release())>>
+    : std::true_type {};
+
+/**
+ * This enum is used for classifying the type of pointer that is stored
+ * within a NativeWeakPtr. This classification is different from the one used
+ * for normal native pointers.
+ */
+enum class NativePtrInternalType : size_t {
+  OWNING = 1,
+  WEAK = 2,
+  REFPTR = 3,
+};
+
+/**
+ * NativePtrInternalPicker uses some C++ SFINAE template-fu to figure out
+ * what type of pointer the class specified by Impl needs to be.
+ *
+ * It does this by supplying multiple overloads of a method named Test.
+ * Various overloads are enabled or disabled depending on whether or not Impl
+ * can possibly support them.
+ *
+ * Each overload "returns" a reference to an array whose size corresponds to the
+ * value of each enum in NativePtrInternalType. That size is then converted back
+ * to the enum value, yielding the right type.
+ */
+template <class Impl>
+class NativePtrInternalPicker {
+  // Enable if Impl derives from SupportsWeakPtr, yielding type WEAK
+  template <class I>
+  static std::enable_if_t<
+      std::is_base_of<SupportsWeakPtr, I>::value,
+      char (&)[static_cast<size_t>(NativePtrInternalType::WEAK)]>
+  Test(char);
+
+  // Enable if Impl implements AddRef and Release, yielding type REFPTR
+  template <class I, typename = decltype(&I::AddRef, &I::Release)>
+  static char (&Test(int))[static_cast<size_t>(NativePtrInternalType::REFPTR)];
+
+  // This overload uses '...' as its param to make its arguments less specific;
+  // the compiler prefers more-specific overloads to less-specific ones.
+  // OWNING is the fallback type.
+  template <class>
+  static char (&Test(...))[static_cast<size_t>(NativePtrInternalType::OWNING)];
+
+ public:
+  // Given a hypothetical function call Test<Impl>, convert the size of its
+  // resulting array back into a NativePtrInternalType enum value.
+  static const NativePtrInternalType value = static_cast<NativePtrInternalType>(
+      sizeof(Test<Impl>('\0')) / sizeof(char));
+};
+
+/**
+ * This enum is used for classifying the type of pointer that is stored in a
+ * JNIObject's handle.
+ *
+ * We have two different weak pointer types:
+ *   * WEAK_INTRUSIVE is a pointer to a class that derives from
+ *     mozilla::SupportsWeakPtr.
+ *   * WEAK_NON_INTRUSIVE is a pointer to a class that does not have any
+ *     internal support for weak pointers, but does supply a
+ *     OnWeakNonIntrusiveDetach method.
+ */
+enum class NativePtrType : size_t {
+  OWNING = 1,
+  WEAK_INTRUSIVE = 2,
+  WEAK_NON_INTRUSIVE = 3,
+  REFPTR = 4,
+};
+
+/**
+ * NativePtrPicker uses some C++ SFINAE template-fu to figure out what type of
+ * pointer the class specified by Impl needs to be.
+ *
+ * It does this by supplying multiple overloads of a method named Test.
+ * Various overloads are enabled or disabled depending on whether or not Impl
+ * can possibly support them.
+ *
+ * Each overload "returns" a reference to an array whose size corresponds to the
+ * value of each enum in NativePtrInternalType. That size is then converted back
+ * to the enum value, yielding the right type.
+ */
+template <class Impl>
+class NativePtrPicker {
+  // Just shorthand for each overload's return type
+  template <NativePtrType PtrType>
+  using ResultTypeT = char (&)[static_cast<size_t>(PtrType)];
+
+  // Enable if Impl derives from SupportsWeakPtr, yielding type WEAK_INTRUSIVE
+  template <typename I>
+  static auto Test(void*)
+      -> std::enable_if_t<std::is_base_of<SupportsWeakPtr, I>::value,
+                          ResultTypeT<NativePtrType::WEAK_INTRUSIVE>>;
+
+  // Enable if Impl implements OnWeakNonIntrusiveDetach, yielding type
+  // WEAK_NON_INTRUSIVE
+  template <typename I>
+  static auto Test(void*)
+      -> std::enable_if_t<HasWeakNonIntrusiveDetach<I>::value,
+                          ResultTypeT<NativePtrType::WEAK_NON_INTRUSIVE>>;
+
+  // We want the WEAK_NON_INTRUSIVE overload to take precedence over this one,
+  // so we only enable this overload if Impl is refcounted AND it does not
+  // implement OnWeakNonIntrusiveDetach. Yields type REFPTR.
+  template <typename I>
+  static auto Test(void*) -> std::enable_if_t<
+      std::conjunction_v<IsRefCounted<I>,
+                         std::negation<HasWeakNonIntrusiveDetach<I>>>,
+      ResultTypeT<NativePtrType::REFPTR>>;
+
+  // This overload uses '...' as its param to make its arguments less specific;
+  // the compiler prefers more-specific overloads to less-specific ones.
+  // OWNING is the fallback type.
+  template <typename>
+  static char (&Test(...))[static_cast<size_t>(NativePtrType::OWNING)];
+
+ public:
+  // Given a hypothetical function call Test<Impl>, convert the size of its
+  // resulting array back into a NativePtrType enum value.
+  static const NativePtrType value =
+      static_cast<NativePtrType>(sizeof(Test<Impl>(nullptr)));
+};
+
+template <class Impl>
+inline uintptr_t CheckNativeHandle(JNIEnv* env, uintptr_t handle) {
+  if (!handle) {
+    if (!env->ExceptionCheck()) {
+      ThrowException(env, "java/lang/NullPointerException",
+                     NullHandle<Impl>().str);
+    }
+    return 0;
+  }
+  return handle;
+}
+
+/**
+ * This struct is used to describe various traits of a native pointer of type
+ * Impl that will be attached to a JNIObject.
+ *
+ * See the definition of the NativePtrType::OWNING specialization for comments
+ * describing the required fields.
+ */
+template <class Impl, NativePtrType Type = NativePtrPicker<Impl>::value>
+struct NativePtrTraits;
+
+template <class Impl>
+struct NativePtrTraits<Impl, /* Type = */ NativePtrType::OWNING> {
+  using AccessorType =
+      Impl*;  // Pointer-like type returned by Access() (an actual pointer in
+              // this case, but this is not strictly necessary)
+  using HandleType = Impl*;  // Type of the pointer stored in JNIObject.mHandle
+  using RefType = Impl*;     // Type of the pointer returned by Get()
+
+  /**
+   * Returns a RefType to the native implementation belonging to
+   * the given Java object.
+   */
+  static RefType Get(JNIEnv* env, jobject instance) {
+    static_assert(
+        std::is_same<HandleType, RefType>::value,
+        "HandleType and RefType must be identical for owning pointers");
+    return reinterpret_cast<HandleType>(
+        CheckNativeHandle<Impl>(env, GetNativeHandle(env, instance)));
+  }
+
+  /**
+   * Returns a RefType to the native implementation belonging to
+   * the given Java object.
+   */
+  template <class LocalRef>
+  static RefType Get(const LocalRef& instance) {
+    return Get(instance.Env(), instance.Get());
+  }
+
+  /**
+   * Given a RefType, returns the pointer-like AccessorType used for
+   * manipulating the native object.
+   */
+  static AccessorType Access(RefType aImpl, JNIEnv* aEnv = nullptr) {
+    static_assert(
+        std::is_same<AccessorType, RefType>::value,
+        "AccessorType and RefType must be identical for owning pointers");
+    return aImpl;
+  }
+
+  /**
+   * Set the JNIObject's handle to the provided pointer, clearing any previous
+   * handle if necessary.
+   */
+  template <class LocalRef>
+  static void Set(const LocalRef& instance, UniquePtr<Impl>&& ptr) {
+    Clear(instance);
+    SetNativeHandle(instance.Env(), instance.Get(),
+                    reinterpret_cast<uintptr_t>(ptr.release()));
+    MOZ_CATCH_JNI_EXCEPTION(instance.Env());
+  }
+
+  /**
+   * Clear the JNIObject's handle.
+   */
+  template <class LocalRef>
+  static void Clear(const LocalRef& instance) {
+    UniquePtr<Impl> ptr(reinterpret_cast<RefType>(
+        GetNativeHandle(instance.Env(), instance.Get())));
+    MOZ_CATCH_JNI_EXCEPTION(instance.Env());
+
+    if (ptr) {
+      SetNativeHandle(instance.Env(), instance.Get(), 0);
+      MOZ_CATCH_JNI_EXCEPTION(instance.Env());
+    }
+  }
+};
+
+template <class Impl>
+struct NativePtrTraits<Impl, /* Type = */ NativePtrType::WEAK_INTRUSIVE> {
+  using AccessorType = Impl*;
+  using HandleType = WeakPtr<Impl>*;
+  using RefType = WeakPtr<Impl>;
+
+  static RefType Get(JNIEnv* env, jobject instance) {
+    const auto ptr = reinterpret_cast<HandleType>(
+        CheckNativeHandle<Impl>(env, GetNativeHandle(env, instance)));
+    return *ptr;
+  }
+
+  template <class LocalRef>
+  static RefType Get(const LocalRef& instance) {
+    return Get(instance.Env(), instance.Get());
+  }
+
+  static AccessorType Access(RefType aPtr, JNIEnv* aEnv = nullptr) {
+    AccessorType const impl = *aPtr;
+    if (!impl) {
+      JNIEnv* env = aEnv ? aEnv : mozilla::jni::GetEnvForThread();
+      ThrowException(env, "java/lang/NullPointerException",
+                     NullWeakPtr<Impl>().str);
+    }
+
+    return impl;
+  }
+
+  template <class LocalRef>
+  static void Set(const LocalRef& instance, Impl* ptr) {
+    // Create the new handle first before clearing any old handle, so the
+    // new handle is guaranteed to have different value than any old handle.
+    const uintptr_t handle =
+        reinterpret_cast<uintptr_t>(new WeakPtr<Impl>(ptr));
+    Clear(instance);
+    SetNativeHandle(instance.Env(), instance.Get(), handle);
+    MOZ_CATCH_JNI_EXCEPTION(instance.Env());
+  }
+
+  template <class LocalRef>
+  static void Clear(const LocalRef& instance) {
+    const auto ptr = reinterpret_cast<HandleType>(
+        GetNativeHandle(instance.Env(), instance.Get()));
+    MOZ_CATCH_JNI_EXCEPTION(instance.Env());
+
+    if (ptr) {
+      SetNativeHandle(instance.Env(), instance.Get(), 0);
+      MOZ_CATCH_JNI_EXCEPTION(instance.Env());
+      delete ptr;
+    }
+  }
+};
+
+template <class Impl>
+struct NativePtrTraits<Impl, /* Type = */ NativePtrType::REFPTR> {
+  using AccessorType = Impl*;
+  using HandleType = RefPtr<Impl>*;
+  using RefType = Impl*;
+
+  static RefType Get(JNIEnv* env, jobject instance) {
+    const auto ptr = reinterpret_cast<HandleType>(
+        CheckNativeHandle<Impl>(env, GetNativeHandle(env, instance)));
+    if (!ptr) {
+      return nullptr;
+    }
+
+    MOZ_ASSERT(*ptr);
+    return *ptr;
+  }
+
+  template <class LocalRef>
+  static RefType Get(const LocalRef& instance) {
+    return Get(instance.Env(), instance.Get());
+  }
+
+  static AccessorType Access(RefType aImpl, JNIEnv* aEnv = nullptr) {
+    static_assert(std::is_same<AccessorType, RefType>::value,
+                  "AccessorType and RefType must be identical for refpointers");
+    return aImpl;
+  }
+
+  template <class LocalRef>
+  static void Set(const LocalRef& instance, RefType ptr) {
+    // Create the new handle first before clearing any old handle, so the
+    // new handle is guaranteed to have different value than any old handle.
+    const uintptr_t handle = reinterpret_cast<uintptr_t>(new RefPtr<Impl>(ptr));
+    Clear(instance);
+    SetNativeHandle(instance.Env(), instance.Get(), handle);
+    MOZ_CATCH_JNI_EXCEPTION(instance.Env());
+  }
+
+  template <class LocalRef>
+  static void Clear(const LocalRef& instance) {
+    const auto ptr = reinterpret_cast<HandleType>(
+        GetNativeHandle(instance.Env(), instance.Get()));
+    MOZ_CATCH_JNI_EXCEPTION(instance.Env());
+
+    if (ptr) {
+      SetNativeHandle(instance.Env(), instance.Get(), 0);
+      MOZ_CATCH_JNI_EXCEPTION(instance.Env());
+      delete ptr;
+    }
+  }
+};
+
+}  // namespace detail
+
+// Forward declarations
+template <typename NativeImpl>
+class NativeWeakPtr;
+template <typename NativeImpl>
+class NativeWeakPtrHolder;
+
+namespace detail {
+
+/**
+ * Given the class of a native implementation, as well as its
+ * NativePtrInternalType, resolve traits for that type that will be used by
+ * the NativeWeakPtrControlBlock.
+ *
+ * Note that we only implement specializations for OWNING and REFPTR types,
+ * as a WEAK_INTRUSIVE type should not be using NativeWeakPtr anyway. The build
+ * will fail if such an attempt is made.
+ *
+ * Traits need to implement two things:
+ * 1. A |Type| field that resolves to a pointer type to be stored in the
+ *    JNIObject's handle. It is assumed that setting a |Type| object to nullptr
+ *    is sufficient to delete the underlying object.
+ * 2. A static |AsRaw| method that converts a pointer of |Type| into a raw
+ *    pointer.
+ */
+template <
+    typename NativeImpl,
+    NativePtrInternalType PtrType =
+        ::mozilla::jni::detail::NativePtrInternalPicker<NativeImpl>::value>
+struct NativeWeakPtrControlBlockStorageTraits;
+
+template <typename NativeImpl>
+struct NativeWeakPtrControlBlockStorageTraits<
+    NativeImpl, ::mozilla::jni::detail::NativePtrInternalType::OWNING> {
+  using Type = UniquePtr<NativeImpl>;
+
+  static NativeImpl* AsRaw(const Type& aStorage) { return aStorage.get(); }
+};
+
+template <typename NativeImpl>
+struct NativeWeakPtrControlBlockStorageTraits<
+    NativeImpl, ::mozilla::jni::detail::NativePtrInternalType::REFPTR> {
+  using Type = RefPtr<NativeImpl>;
+
+  static NativeImpl* AsRaw(const Type& aStorage) { return aStorage.get(); }
+};
+
+// Forward Declaration
+template <typename NativeImpl>
+class Accessor;
+
+/**
+ * This class contains the shared data that is referenced by all NativeWeakPtr
+ * objects that reference the same object.
+ *
+ * It retains a WeakRef to the Java object that owns this native object.
+ * It uses a RWLock to control access to the native pointer itself.
+ * Read locks are used when accessing the pointer (even when calling non-const
+ * methods on the native object).
+ * A write lock is only used when it is time to destroy the native object and
+ * we need to clear the value of mNativeImpl.
+ */
+template <typename NativeImpl>
+class MOZ_HEAP_CLASS NativeWeakPtrControlBlock final {
+ public:
+  using StorageTraits = NativeWeakPtrControlBlockStorageTraits<NativeImpl>;
+  using StorageType = typename StorageTraits::Type;
+
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(NativeWeakPtrControlBlock)
+
+  NativeWeakPtrControlBlock(const NativeWeakPtrControlBlock&) = delete;
+  NativeWeakPtrControlBlock(NativeWeakPtrControlBlock&&) = delete;
+  NativeWeakPtrControlBlock& operator=(const NativeWeakPtrControlBlock&) =
+      delete;
+  NativeWeakPtrControlBlock& operator=(NativeWeakPtrControlBlock&&) = delete;
+
+  // This is safe to call on any thread because mJavaOwner is immutable.
+  mozilla::jni::Object::WeakRef GetJavaOwner() const { return mJavaOwner; }
+
+ private:
+  NativeWeakPtrControlBlock(::mozilla::jni::Object::Param aJavaOwner,
+                            StorageType&& aNativeImpl)
+      : mJavaOwner(aJavaOwner),
+        mLock("mozilla::jni::detail::NativeWeakPtrControlBlock"),
+        mNativeImpl(std::move(aNativeImpl)) {}
+
+  ~NativeWeakPtrControlBlock() {
+    // Make sure that somebody, somewhere, has detached us before destroying.
+    MOZ_ASSERT(!(*this));
+  }
+
+  /**
+   * Clear the native pointer so that subsequent accesses to the native pointer
+   * via this control block are no longer available.
+   *
+   * We return the native pointer to the caller so that it may proceed with
+   * cleaning up its resources.
+   */
+  StorageType Clear() {
+    StorageType nativeImpl(nullptr);
+
+    {  // Scope for lock
+      AutoWriteLock lock(mLock);
+      std::swap(mNativeImpl, nativeImpl);
+    }
+
+    return nativeImpl;
+  }
+
+  MOZ_PUSH_IGNORE_THREAD_SAFETY
+  void Lock() const { mLock.ReadLock(); }
+
+  void Unlock() const { mLock.ReadUnlock(); }
+  MOZ_POP_THREAD_SAFETY
+
+#if defined(DEBUG)
+  // This is kind of expensive, so we only support it in debug builds.
+  explicit operator bool() const {
+    AutoReadLock lock(mLock);
+    return !!mNativeImpl;
+  }
+#endif  // defined(DEBUG)
+
+ private:
+  friend class Accessor<NativeImpl>;
+  friend class NativeWeakPtr<NativeImpl>;
+  friend class NativeWeakPtrHolder<NativeImpl>;
+
+ private:
+  const mozilla::jni::Object::WeakRef mJavaOwner;
+  mutable RWLock mLock MOZ_UNANNOTATED;  // Protects mNativeImpl
+  StorageType mNativeImpl;
+};
+
+/**
+ * If you want to temporarily access the object held by a NativeWeakPtr, you
+ * must obtain one of these Accessor objects from the pointer. Access must
+ * be done _exclusively_ using once of these objects!
+ */
+template <typename NativeImpl>
+class MOZ_STACK_CLASS Accessor final {
+ public:
+  ~Accessor() {
+    if (mCtlBlock) {
+      mCtlBlock->Unlock();
+    }
+  }
+
+  // Check whether the object is still valid before doing anything else
+  explicit operator bool() const { return mCtlBlock && mCtlBlock->mNativeImpl; }
+
+  // Normal member access
+  NativeImpl* operator->() const {
+    return NativeWeakPtrControlBlockStorageTraits<NativeImpl>::AsRaw(
+        mCtlBlock->mNativeImpl);
+  }
+
+  // This allows us to support calling a pointer to a member function
+  template <typename Member>
+  auto operator->*(Member aMember) const {
+    NativeImpl* impl =
+        NativeWeakPtrControlBlockStorageTraits<NativeImpl>::AsRaw(
+            mCtlBlock->mNativeImpl);
+    return [impl, member = aMember](auto&&... aArgs) {
+      return (impl->*member)(std::forward<decltype(aArgs)>(aArgs)...);
+    };
+  }
+
+  // Only available for NativeImpl types that actually use refcounting.
+  // The idea here is that it should be possible to obtain a strong ref from
+  // a NativeWeakPtr if and only if NativeImpl supports refcounting.
+  template <typename I = NativeImpl>
+  auto AsRefPtr() const -> std::enable_if_t<IsRefCounted<I>::value, RefPtr<I>> {
+    MOZ_ASSERT(I::HasThreadSafeRefCnt::value || NS_IsMainThread());
+    return mCtlBlock->mNativeImpl;
+  }
+
+  Accessor(const Accessor&) = delete;
+  Accessor(Accessor&&) = delete;
+  Accessor& operator=(const Accessor&) = delete;
+  Accessor& operator=(Accessor&&) = delete;
+
+ private:
+  explicit Accessor(
+      const RefPtr<detail::NativeWeakPtrControlBlock<NativeImpl>>& aCtlBlock)
+      : mCtlBlock(aCtlBlock) {
+    if (aCtlBlock) {
+      aCtlBlock->Lock();
+    }
+  }
+
+ private:
+  friend class NativeWeakPtr<NativeImpl>;
+  friend class NativeWeakPtrHolder<NativeImpl>;
+
+ private:
+  const RefPtr<NativeWeakPtrControlBlock<NativeImpl>> mCtlBlock;
+};
+
+}  // namespace detail
+
+using DetachPromise = mozilla::MozPromise<bool, nsresult, true>;
+
+/**
+ * This class implements support for thread-safe weak pointers to native objects
+ * that are owned by Java objects deriving from JNIObject.
+ *
+ * Any code that wants to access such a native object must have a copy of
+ * a NativeWeakPtr to that object.
+ */
+template <typename NativeImpl>
+class NativeWeakPtr {
+ public:
+  using Accessor = detail::Accessor<NativeImpl>;
+
+  /**
+   * Call this method to access the underlying object referenced by this
+   * NativeWeakPtr.
+   *
+   * Always check the returned Accessor object for availability before calling
+   * methods on it.
+   *
+   * For example, given:
+   *
+   * NativeWeakPtr<Foo> foo;
+   * auto accessor = foo.Access();
+   * if (accessor) {
+   *   // Okay, safe to work with
+   *   accessor->DoStuff();
+   * } else {
+   *   // The object's strong reference was cleared and is no longer available!
+   * }
+   */
+  Accessor Access() const { return Accessor(mCtlBlock); }
+
+  /**
+   * Detach the underlying object's strong reference from its owning Java object
+   * and clean it up.
+   */
+  RefPtr<DetachPromise> Detach();
+
+  /**
+   * This method does not indicate whether or not the weak pointer is still
+   * valid; it only indicates whether we're actually attached to one.
+   */
+  bool IsAttached() const { return !!mCtlBlock; }
+
+  /**
+   * Does this pointer reference the same object as the one referenced by the
+   * provided Accessor?
+   */
+  bool IsSame(const Accessor& aAccessor) const {
+    return mCtlBlock == aAccessor.mCtlBlock;
+  }
+
+  /**
+   * Does this pointer reference the same object as the one referenced by the
+   * provided Control Block?
+   */
+  bool IsSame(const RefPtr<detail::NativeWeakPtrControlBlock<NativeImpl>>&
+                  aOther) const {
+    return mCtlBlock == aOther;
+  }
+
+  NativeWeakPtr() = default;
+  MOZ_IMPLICIT NativeWeakPtr(decltype(nullptr)) {}
+  NativeWeakPtr(const NativeWeakPtr& aOther) = default;
+  NativeWeakPtr(NativeWeakPtr&& aOther) = default;
+  NativeWeakPtr& operator=(const NativeWeakPtr& aOther) = default;
+  NativeWeakPtr& operator=(NativeWeakPtr&& aOther) = default;
+
+  NativeWeakPtr& operator=(decltype(nullptr)) {
+    mCtlBlock = nullptr;
+    return *this;
+  }
+
+ protected:
+  // Construction of initial NativeWeakPtr for aCtlBlock
+  explicit NativeWeakPtr(
+      already_AddRefed<detail::NativeWeakPtrControlBlock<NativeImpl>> aCtlBlock)
+      : mCtlBlock(aCtlBlock) {}
+
+ private:
+  // Construction of subsequent NativeWeakPtrs for aCtlBlock
+  explicit NativeWeakPtr(
+      const RefPtr<detail::NativeWeakPtrControlBlock<NativeImpl>>& aCtlBlock)
+      : mCtlBlock(aCtlBlock) {}
+
+  friend class NativeWeakPtrHolder<NativeImpl>;
+
+ protected:
+  RefPtr<detail::NativeWeakPtrControlBlock<NativeImpl>> mCtlBlock;
+};
+
+/**
+ * A pointer to an instance of this class should be stored in a Java object's
+ * JNIObject handle. New instances of native objects wrapped by NativeWeakPtr
+ * are created using the static methods of this class.
+ *
+ * Why do we have distinct methods here instead of using AttachNative like other
+ * pointer types that may be stored in JNIObject?
+ *
+ * Essentially, we want the creation and use of NativeWeakPtr to be as
+ * deliberate as possible. Forcing a different creation mechanism is part of
+ * that emphasis.
+ *
+ * Example:
+ *
+ * class NativeFoo {
+ *  public:
+ *   NativeFoo();
+ *   void Bar();
+ *   // The following method is required to be used with NativeWeakPtr
+ *   void OnWeakNonIntrusiveDetach(already_AddRefed<Runnable> aDisposer);
+ * };
+ *
+ * java::Object::LocalRef javaObj(...);
+ *
+ * // Create a new Foo that is attached to javaObj
+ * auto weakFoo = NativeWeakPtrHolder<NativeFoo>::Attach(javaObj);
+ *
+ * // Now I can save weakFoo, access it, do whatever I want
+ * if (auto accWeakFoo = weakFoo.Access()) {
+ *   accWeakFoo->Bar();
+ * }
+ *
+ * // Detach from javaObj and clean up
+ * weakFoo.Detach();
+ */
+template <typename NativeImpl>
+class MOZ_HEAP_CLASS NativeWeakPtrHolder final
+    : public NativeWeakPtr<NativeImpl> {
+  using Base = NativeWeakPtr<NativeImpl>;
+
+ public:
+  using Accessor = typename Base::Accessor;
+  using StorageTraits =
+      typename detail::NativeWeakPtrControlBlock<NativeImpl>::StorageTraits;
+  using StorageType = typename StorageTraits::Type;
+
+  /**
+   * Create a new NativeImpl object, wrap it in a NativeWeakPtr, and store it
+   * in the Java object's JNIObject handle.
+   *
+   * @return A NativeWeakPtr object that references the newly-attached object.
+   */
+  template <typename Cls, typename JNIType, typename... Args>
+  static NativeWeakPtr<NativeImpl> Attach(const Ref<Cls, JNIType>& aJavaObject,
+                                          Args&&... aArgs) {
+    MOZ_RELEASE_ASSERT(NS_IsMainThread());
+
+    StorageType nativeImpl(new NativeImpl(std::forward<Args>(aArgs)...));
+    return AttachInternal(aJavaObject, std::move(nativeImpl));
+  }
+
+  /**
+   * Given a new NativeImpl object, wrap it in a NativeWeakPtr, and store it
+   * in the Java object's JNIObject handle.
+   *
+   * @return A NativeWeakPtr object that references the newly-attached object.
+   */
+  template <typename Cls, typename JNIType>
+  static NativeWeakPtr<NativeImpl> AttachExisting(
+      const Ref<Cls, JNIType>& aJavaObject,
+      already_AddRefed<NativeImpl> aNativeImpl) {
+    MOZ_RELEASE_ASSERT(NS_IsMainThread());
+
+    StorageType nativeImpl(aNativeImpl);
+    return AttachInternal(aJavaObject, std::move(nativeImpl));
+  }
+
+  ~NativeWeakPtrHolder() = default;
+
+  MOZ_IMPLICIT NativeWeakPtrHolder(decltype(nullptr)) = delete;
+  NativeWeakPtrHolder(const NativeWeakPtrHolder&) = delete;
+  NativeWeakPtrHolder(NativeWeakPtrHolder&&) = delete;
+  NativeWeakPtrHolder& operator=(const NativeWeakPtrHolder&) = delete;
+  NativeWeakPtrHolder& operator=(NativeWeakPtrHolder&&) = delete;
+  NativeWeakPtrHolder& operator=(decltype(nullptr)) = delete;
+
+ private:
+  template <typename Cls>
+  NativeWeakPtrHolder(const LocalRef<Cls>& aJavaObject,
+                      StorageType&& aNativeImpl)
+      : NativeWeakPtr<NativeImpl>(
+            do_AddRef(new NativeWeakPtrControlBlock<NativeImpl>(
+                aJavaObject, std::move(aNativeImpl)))) {}
+
+  /**
+   * Internal function that actually wraps the native pointer, binds it to the
+   * JNIObject, and then returns the NativeWeakPtr result.
+   */
+  template <typename Cls, typename JNIType>
+  static NativeWeakPtr<NativeImpl> AttachInternal(
+      const Ref<Cls, JNIType>& aJavaObject, StorageType&& aPtr) {
+    auto localJavaObject = ToLocalRef(aJavaObject);
+    NativeWeakPtrHolder<NativeImpl>* holder =
+        new NativeWeakPtrHolder<NativeImpl>(localJavaObject, std::move(aPtr));
+    static_assert(
+        NativePtrPicker<NativeImpl>::value == NativePtrType::WEAK_NON_INTRUSIVE,
+        "This type is not compatible with mozilla::jni::NativeWeakPtr");
+    NativePtrTraits<NativeImpl>::Set(localJavaObject, holder);
+    return NativeWeakPtr<NativeImpl>(holder->mCtlBlock);
+  }
+};
+
+namespace detail {
+
+/**
+ * NativePtrTraits for the WEAK_NON_INTRUSIVE pointer type.
+ */
+template <class Impl>
+struct NativePtrTraits<Impl, /* Type = */ NativePtrType::WEAK_NON_INTRUSIVE> {
+  using AccessorType = typename NativeWeakPtrHolder<Impl>::Accessor;
+  using HandleType = NativeWeakPtrHolder<Impl>*;
+  using RefType = NativeWeakPtrHolder<Impl>* const;
+
+  static RefType Get(JNIEnv* env, jobject instance) {
+    return GetHandle(env, instance);
+  }
+
+  template <typename Cls>
+  static RefType Get(const LocalRef<Cls>& instance) {
+    return GetHandle(instance.Env(), instance.Get());
+  }
+
+  static AccessorType Access(RefType aPtr) { return aPtr->Access(); }
+
+  template <typename Cls>
+  static void Set(const LocalRef<Cls>& instance, HandleType ptr) {
+    MOZ_RELEASE_ASSERT(NS_IsMainThread());
+    const uintptr_t handle = reinterpret_cast<uintptr_t>(ptr);
+    Clear(instance);
+    SetNativeHandle(instance.Env(), instance.Get(), handle);
+    MOZ_CATCH_JNI_EXCEPTION(instance.Env());
+  }
+
+  template <typename Cls>
+  static void Clear(const LocalRef<Cls>& instance) {
+    auto ptr = reinterpret_cast<HandleType>(
+        GetNativeHandle(instance.Env(), instance.Get()));
+    MOZ_CATCH_JNI_EXCEPTION(instance.Env());
+
+    if (!ptr) {
+      return;
+    }
+
+    ptr->Detach();
+  }
+
+  // This call is not safe to do unless we know for sure that instance's
+  // native handle has not changed. It is up to NativeWeakPtrDetachRunnable
+  // to perform this check.
+  template <typename Cls>
+  static void ClearFinish(const LocalRef<Cls>& instance) {
+    MOZ_RELEASE_ASSERT(NS_IsMainThread());
+    JNIEnv* const env = instance.Env();
+    auto ptr =
+        reinterpret_cast<HandleType>(GetNativeHandle(env, instance.Get()));
+    MOZ_CATCH_JNI_EXCEPTION(env);
+    MOZ_RELEASE_ASSERT(!!ptr);
+
+    SetNativeHandle(env, instance.Get(), 0);
+    MOZ_CATCH_JNI_EXCEPTION(env);
+    // Deletion of ptr is done by the caller
+  }
+
+  // The call is stale if the native object has been destroyed on the
+  // Gecko side, but the Java object is still attached to it through
+  // a weak pointer. Stale calls should be discarded. Note that it's
+  // an error if holder is nullptr here; we return false but the
+  // native call will throw an error.
+  template <class LocalRef>
+  static bool IsStale(const LocalRef& instance) {
+    JNIEnv* const env = mozilla::jni::GetEnvForThread();
+
+    // We cannot use Get here because that method throws an exception when the
+    // object is null, which is a valid state for a stale call.
+    const auto holder =
+        reinterpret_cast<HandleType>(GetNativeHandle(env, instance.Get()));
+    MOZ_CATCH_JNI_EXCEPTION(env);
+
+    if (!holder || !holder->IsAttached()) {
+      return true;
+    }
+
+    auto acc(holder->Access());
+    return !acc;
+  }
+
+ private:
+  static HandleType GetHandle(JNIEnv* env, jobject instance) {
+    return reinterpret_cast<HandleType>(
+        CheckNativeHandle<Impl>(env, GetNativeHandle(env, instance)));
+  }
+
+  template <typename Cls>
+  static HandleType GetHandle(const LocalRef<Cls>& instance) {
+    return GetHandle(instance.Env(), instance.Get());
+  }
+
+  friend class NativeWeakPtrHolder<Impl>;
+};
+
+}  // namespace detail
+
+using namespace detail;
+
+/**
+ * For JNI native methods that are dispatched to a proxy, i.e. using
+ * @WrapForJNI(dispatchTo = "proxy"), the implementing C++ class must provide a
+ * OnNativeCall member. Subsequently, every native call is automatically
+ * wrapped in a functor object, and the object is passed to OnNativeCall. The
+ * OnNativeCall implementation can choose to invoke the call, save it, dispatch
+ * it to a different thread, etc. Each copy of functor may only be invoked
+ * once.
+ *
+ * class MyClass : public MyJavaClass::Natives<MyClass>
+ * {
+ *     // ...
+ *
+ *     template<class Functor>
+ *     class ProxyRunnable final : public Runnable
+ *     {
+ *         Functor mCall;
+ *     public:
+ *         ProxyRunnable(Functor&& call) : mCall(std::move(call)) {}
+ *         virtual void run() override { mCall(); }
+ *     };
+ *
+ * public:
+ *     template<class Functor>
+ *     static void OnNativeCall(Functor&& call)
+ *     {
+ *         RunOnAnotherThread(new ProxyRunnable(std::move(call)));
+ *     }
+ * };
+ */
+
+namespace detail {
+
+// ProxyArg is used to handle JNI ref arguments for proxies. Because a proxied
+// call may happen outside of the original JNI native call, we must save all
+// JNI ref arguments as global refs to avoid the arguments going out of scope.
+template <typename T>
+struct ProxyArg {
+  static_assert(std::is_trivial_v<T> && std::is_standard_layout_v<T>,
+                "T must be primitive type");
+
+  // Primitive types can be saved by value.
+  typedef T Type;
+  typedef typename TypeAdapter<T>::JNIType JNIType;
+
+  static void Clear(JNIEnv* env, Type&) {}
+
+  static Type From(JNIEnv* env, JNIType val) {
+    return TypeAdapter<T>::ToNative(env, val);
+  }
+};
+
+template <class C, typename T>
+struct ProxyArg<Ref<C, T>> {
+  // Ref types need to be saved by global ref.
+  typedef typename C::GlobalRef Type;
+  typedef typename TypeAdapter<Ref<C, T>>::JNIType JNIType;
+
+  static void Clear(JNIEnv* env, Type& ref) { ref.Clear(env); }
+
+  static Type From(JNIEnv* env, JNIType val) {
+    return Type(env, C::Ref::From(val));
+  }
+};
+
+template <typename C>
+struct ProxyArg<const C&> : ProxyArg<C> {};
+template <>
+struct ProxyArg<StringParam> : ProxyArg<String::Ref> {};
+template <class C>
+struct ProxyArg<LocalRef<C>> : ProxyArg<typename C::Ref> {};
+
+// ProxyNativeCall implements the functor object that is passed to OnNativeCall
+template <class Impl, class Owner, bool IsStatic,
+          bool HasThisArg /* has instance/class local ref in the call */,
+          typename... Args>
+class ProxyNativeCall {
+  // "this arg" refers to the Class::LocalRef (for static methods) or
+  // Owner::LocalRef (for instance methods) that we optionally (as indicated
+  // by HasThisArg) pass into the destination C++ function.
+  using ThisArgClass = std::conditional_t<IsStatic, Class, Owner>;
+  using ThisArgJNIType = std::conditional_t<IsStatic, jclass, jobject>;
+
+  // Type signature of the destination C++ function, which matches the
+  // Method template parameter in NativeStubImpl::Wrap.
+  using NativeCallType = std::conditional_t<
+      IsStatic,
+      std::conditional_t<HasThisArg, void (*)(const Class::LocalRef&, Args...),
+                         void (*)(Args...)>,
+      std::conditional_t<
+          HasThisArg, void (Impl::*)(const typename Owner::LocalRef&, Args...),
+          void (Impl::*)(Args...)>>;
+
+  // Destination C++ function.
+  NativeCallType mNativeCall;
+  // Saved this arg.
+  typename ThisArgClass::GlobalRef mThisArg;
+  // Saved arguments.
+  std::tuple<typename ProxyArg<Args>::Type...> mArgs;
+
+  // We cannot use IsStatic and HasThisArg directly (without going through
+  // extra hoops) because GCC complains about invalid overloads, so we use
+  // another pair of template parameters, Static and ThisArg.
+
+  template <bool Static, bool ThisArg, size_t... Indices>
+  std::enable_if_t<Static && ThisArg, void> Call(
+      const Class::LocalRef& cls, std::index_sequence<Indices...>) const {
+    (*mNativeCall)(cls, std::get<Indices>(mArgs)...);
+  }
+
+  template <bool Static, bool ThisArg, size_t... Indices>
+  std::enable_if_t<Static && !ThisArg, void> Call(
+      const Class::LocalRef& cls, std::index_sequence<Indices...>) const {
+    (*mNativeCall)(std::get<Indices>(mArgs)...);
+  }
+
+  template <bool Static, bool ThisArg, size_t... Indices>
+  std::enable_if_t<!Static && ThisArg, void> Call(
+      const typename Owner::LocalRef& inst,
+      std::index_sequence<Indices...>) const {
+    auto impl = NativePtrTraits<Impl>::Access(NativePtrTraits<Impl>::Get(inst));
+    MOZ_CATCH_JNI_EXCEPTION(inst.Env());
+    (impl->*mNativeCall)(inst, std::get<Indices>(mArgs)...);
+  }
+
+  template <bool Static, bool ThisArg, size_t... Indices>
+  std::enable_if_t<!Static && !ThisArg, void> Call(
+      const typename Owner::LocalRef& inst,
+      std::index_sequence<Indices...>) const {
+    auto impl = NativePtrTraits<Impl>::Access(NativePtrTraits<Impl>::Get(inst));
+    MOZ_CATCH_JNI_EXCEPTION(inst.Env());
+    (impl->*mNativeCall)(std::get<Indices>(mArgs)...);
+  }
+
+  template <size_t... Indices>
+  void Clear(JNIEnv* env, std::index_sequence<Indices...>) {
+    int dummy[] = {
+        (ProxyArg<Args>::Clear(env, std::get<Indices>(mArgs)), 0)...};
+    mozilla::Unused << dummy;
+  }
+
+  static decltype(auto) GetNativeObject(Class::Param thisArg) {
+    return nullptr;
+  }
+
+  static decltype(auto) GetNativeObject(typename Owner::Param thisArg) {
+    return NativePtrTraits<Impl>::Access(
+        NativePtrTraits<Impl>::Get(GetEnvForThread(), thisArg.Get()));
+  }
+
+ public:
+  // The class that implements the call target.
+  typedef Impl TargetClass;
+  typedef typename ThisArgClass::Param ThisArgType;
+
+  static const bool isStatic = IsStatic;
+
+  ProxyNativeCall(ThisArgJNIType thisArg, NativeCallType nativeCall,
+                  JNIEnv* env, typename ProxyArg<Args>::JNIType... args)
+      : mNativeCall(nativeCall),
+        mThisArg(env, ThisArgClass::Ref::From(thisArg)),
+        mArgs(ProxyArg<Args>::From(env, args)...) {}
+
+  ProxyNativeCall(ProxyNativeCall&&) = default;
+  ProxyNativeCall(const ProxyNativeCall&) = default;
+
+  // Get class ref for static calls or object ref for instance calls.
+  typename ThisArgClass::Param GetThisArg() const { return mThisArg; }
+
+  // Get the native object targeted by this call.
+  // Returns nullptr for static calls.
+  decltype(auto) GetNativeObject() const { return GetNativeObject(mThisArg); }
+
+  // Return if target is the given function pointer / pointer-to-member.
+  // Because we can only compare pointers of the same type, we use a
+  // templated overload that is chosen only if given a different type of
+  // pointer than our target pointer type.
+  bool IsTarget(NativeCallType call) const { return call == mNativeCall; }
+  template <typename T>
+  bool IsTarget(T&&) const {
+    return false;
+  }
+
+  // Redirect the call to another function / class member with the same
+  // signature as the original target. Crash if given a wrong signature.
+  void SetTarget(NativeCallType call) { mNativeCall = call; }
+  template <typename T>
+  void SetTarget(T&&) const {
+    MOZ_CRASH();
+  }
+
+  void operator()() {
+    JNIEnv* const env = GetEnvForThread();
+    typename ThisArgClass::LocalRef thisArg(env, mThisArg);
+    Call<IsStatic, HasThisArg>(thisArg, std::index_sequence_for<Args...>{});
+
+    // Clear all saved global refs. We do this after the call is invoked,
+    // and not inside the destructor because we already have a JNIEnv here,
+    // so it's more efficient to clear out the saved args here. The
+    // downside is that the call can only be invoked once.
+    Clear(env, std::index_sequence_for<Args...>{});
+    mThisArg.Clear(env);
+  }
+};
+
+template <class Impl, bool HasThisArg, typename... Args>
+struct Dispatcher {
+  template <class Traits, bool IsStatic = Traits::isStatic,
+            typename... ProxyArgs>
+  static std::enable_if_t<Traits::dispatchTarget == DispatchTarget::PROXY, void>
+  Run(ProxyArgs&&... args) {
+    Impl::OnNativeCall(
+        ProxyNativeCall<Impl, typename Traits::Owner, IsStatic, HasThisArg,
+                        Args...>(std::forward<ProxyArgs>(args)...));
+  }
+
+  template <class Traits, bool IsStatic = Traits::isStatic, typename ThisArg,
+            typename... ProxyArgs>
+  static std::enable_if_t<
+      Traits::dispatchTarget == DispatchTarget::GECKO_PRIORITY, void>
+  Run(ThisArg thisArg, ProxyArgs&&... args) {
+    // For a static method, do not forward the "this arg" (i.e. the class
+    // local ref) if the implementation does not request it. This saves us
+    // a pair of calls to add/delete global ref.
+    auto proxy =
+        ProxyNativeCall<Impl, typename Traits::Owner, IsStatic, HasThisArg,
+                        Args...>((HasThisArg || !IsStatic) ? thisArg : nullptr,
+                                 std::forward<ProxyArgs>(args)...);
+    DispatchToGeckoPriorityQueue(
+        NS_NewRunnableFunction("PriorityNativeCall", std::move(proxy)));
+  }
+
+  template <class Traits, bool IsStatic = Traits::isStatic, typename ThisArg,
+            typename... ProxyArgs>
+  static std::enable_if_t<Traits::dispatchTarget == DispatchTarget::GECKO, void>
+  Run(ThisArg thisArg, ProxyArgs&&... args) {
+    // For a static method, do not forward the "this arg" (i.e. the class
+    // local ref) if the implementation does not request it. This saves us
+    // a pair of calls to add/delete global ref.
+    auto proxy =
+        ProxyNativeCall<Impl, typename Traits::Owner, IsStatic, HasThisArg,
+                        Args...>((HasThisArg || !IsStatic) ? thisArg : nullptr,
+                                 std::forward<ProxyArgs>(args)...);
+    NS_DispatchToMainThread(
+        NS_NewRunnableFunction("GeckoNativeCall", std::move(proxy)));
+  }
+
+  template <class Traits, bool IsStatic = false, typename... ProxyArgs>
+  static std::enable_if_t<Traits::dispatchTarget == DispatchTarget::CURRENT,
+                          void>
+  Run(ProxyArgs&&... args) {
+    MOZ_CRASH("Unreachable code");
+  }
+};
+
+}  // namespace detail
+
+// Wrapper methods that convert arguments from the JNI types to the native
+// types, e.g. from jobject to jni::Object::Ref. For instance methods, the
+// wrapper methods also convert calls to calls on objects.
+//
+// We need specialization for static/non-static because the two have different
+// signatures (jobject vs jclass and Impl::*Method vs *Method).
+// We need specialization for return type, because void return type requires
+// us to not deal with the return value.
+
+// Bug 1207642 - Work around Dalvik bug by realigning stack on JNI entry
+#ifdef __i386__
+#  define MOZ_JNICALL JNICALL __attribute__((force_align_arg_pointer))
+#else
+#  define MOZ_JNICALL JNICALL
+#endif
+
+template <class Traits, class Impl, class Args = typename Traits::Args>
+class NativeStub;
+
+template <class Traits, class Impl, typename... Args>
+class NativeStub<Traits, Impl, jni::Args<Args...>> {
+  using Owner = typename Traits::Owner;
+  using ReturnType = typename Traits::ReturnType;
+
+  static constexpr bool isStatic = Traits::isStatic;
+  static constexpr bool isVoid = std::is_void_v<ReturnType>;
+
+  struct VoidType {
+    using JNIType = void;
+  };
+  using ReturnJNIType =
+      typename std::conditional_t<isVoid, VoidType,
+                                  TypeAdapter<ReturnType>>::JNIType;
+
+  using ReturnTypeForNonVoidInstance =
+      std::conditional_t<!isStatic && !isVoid, ReturnType, VoidType>;
+  using ReturnTypeForVoidInstance =
+      std::conditional_t<!isStatic && isVoid, ReturnType, VoidType&>;
+  using ReturnTypeForNonVoidStatic =
+      std::conditional_t<isStatic && !isVoid, ReturnType, VoidType>;
+  using ReturnTypeForVoidStatic =
+      std::conditional_t<isStatic && isVoid, ReturnType, VoidType&>;
+
+  static_assert(Traits::dispatchTarget == DispatchTarget::CURRENT || isVoid,
+                "Dispatched calls must have void return type");
+
+ public:
+  // Non-void instance method
+  template <ReturnTypeForNonVoidInstance (Impl::*Method)(Args...)>
+  static MOZ_JNICALL ReturnJNIType
+  Wrap(JNIEnv* env, jobject instance,
+       typename TypeAdapter<Args>::JNIType... args) {
+    MOZ_ASSERT_JNI_THREAD(Traits::callingThread);
+
+    auto impl = NativePtrTraits<Impl>::Access(
+        NativePtrTraits<Impl>::Get(env, instance));
+    if (!impl) {
+      // There is a pending JNI exception at this point.
+      return ReturnJNIType();
+    }
+    return TypeAdapter<ReturnType>::FromNative(
+        env, (impl->*Method)(TypeAdapter<Args>::ToNative(env, args)...));
+  }
+
+  // Non-void instance method with instance reference
+  template <ReturnTypeForNonVoidInstance (Impl::*Method)(
+      const typename Owner::LocalRef&, Args...)>
+  static MOZ_JNICALL ReturnJNIType
+  Wrap(JNIEnv* env, jobject instance,
+       typename TypeAdapter<Args>::JNIType... args) {
+    MOZ_ASSERT_JNI_THREAD(Traits::callingThread);
+
+    auto impl = NativePtrTraits<Impl>::Access(
+        NativePtrTraits<Impl>::Get(env, instance));
+    if (!impl) {
+      // There is a pending JNI exception at this point.
+      return ReturnJNIType();
+    }
+    auto self = Owner::LocalRef::Adopt(env, instance);
+    const auto res = TypeAdapter<ReturnType>::FromNative(
+        env, (impl->*Method)(self, TypeAdapter<Args>::ToNative(env, args)...));
+    self.Forget();
+    return res;
+  }
+
+  // Void instance method
+  template <ReturnTypeForVoidInstance (Impl::*Method)(Args...)>
+  static MOZ_JNICALL void Wrap(JNIEnv* env, jobject instance,
+                               typename TypeAdapter<Args>::JNIType... args) {
+    MOZ_ASSERT_JNI_THREAD(Traits::callingThread);
+
+    if (Traits::dispatchTarget != DispatchTarget::CURRENT) {
+      Dispatcher<Impl, /* HasThisArg */ false, Args...>::template Run<Traits>(
+          instance, Method, env, args...);
+      return;
+    }
+
+    auto impl = NativePtrTraits<Impl>::Access(
+        NativePtrTraits<Impl>::Get(env, instance));
+    if (!impl) {
+      // There is a pending JNI exception at this point.
+      return;
+    }
+    (impl->*Method)(TypeAdapter<Args>::ToNative(env, args)...);
+  }
+
+  // Void instance method with instance reference
+  template <ReturnTypeForVoidInstance (Impl::*Method)(
+      const typename Owner::LocalRef&, Args...)>
+  static MOZ_JNICALL void Wrap(JNIEnv* env, jobject instance,
+                               typename TypeAdapter<Args>::JNIType... args) {
+    MOZ_ASSERT_JNI_THREAD(Traits::callingThread);
+
+    if (Traits::dispatchTarget != DispatchTarget::CURRENT) {
+      Dispatcher<Impl, /* HasThisArg */ true, Args...>::template Run<Traits>(
+          instance, Method, env, args...);
+      return;
+    }
+
+    auto impl = NativePtrTraits<Impl>::Access(
+        NativePtrTraits<Impl>::Get(env, instance));
+    if (!impl) {
+      // There is a pending JNI exception at this point.
+      return;
+    }
+    auto self = Owner::LocalRef::Adopt(env, instance);
+    (impl->*Method)(self, TypeAdapter<Args>::ToNative(env, args)...);
+    self.Forget();
+  }
+
+  // Overload for DisposeNative
+  template <ReturnTypeForVoidInstance (*DisposeNative)(
+      const typename Owner::LocalRef&)>
+  static MOZ_JNICALL void Wrap(JNIEnv* env, jobject instance) {
+    MOZ_ASSERT_JNI_THREAD(Traits::callingThread);
+
+    if (Traits::dispatchTarget != DispatchTarget::CURRENT) {
+      using LocalRef = typename Owner::LocalRef;
+      Dispatcher<Impl, /* HasThisArg */ false, const LocalRef&>::template Run<
+          Traits, /* IsStatic */ true>(
+          /* ThisArg */ nullptr, DisposeNative, env, instance);
+      return;
+    }
+
+    auto self = Owner::LocalRef::Adopt(env, instance);
+    DisposeNative(self);
+    self.Forget();
+  }
+
+  // Non-void static method
+  template <ReturnTypeForNonVoidStatic (*Method)(Args...)>
+  static MOZ_JNICALL ReturnJNIType
+  Wrap(JNIEnv* env, jclass, typename TypeAdapter<Args>::JNIType... args) {
+    MOZ_ASSERT_JNI_THREAD(Traits::callingThread);
+
+    return TypeAdapter<ReturnType>::FromNative(
+        env, (*Method)(TypeAdapter<Args>::ToNative(env, args)...));
+  }
+
+  // Non-void static method with class reference
+  template <ReturnTypeForNonVoidStatic (*Method)(const Class::LocalRef&,
+                                                 Args...)>
+  static MOZ_JNICALL ReturnJNIType
+  Wrap(JNIEnv* env, jclass cls, typename TypeAdapter<Args>::JNIType... args) {
+    MOZ_ASSERT_JNI_THREAD(Traits::callingThread);
+
+    auto clazz = Class::LocalRef::Adopt(env, cls);
+    const auto res = TypeAdapter<ReturnType>::FromNative(
+        env, (*Method)(clazz, TypeAdapter<Args>::ToNative(env, args)...));
+    clazz.Forget();
+    return res;
+  }
+
+  // Void static method
+  template <ReturnTypeForVoidStatic (*Method)(Args...)>
+  static MOZ_JNICALL void Wrap(JNIEnv* env, jclass cls,
+                               typename TypeAdapter<Args>::JNIType... args) {
+    MOZ_ASSERT_JNI_THREAD(Traits::callingThread);
+
+    if (Traits::dispatchTarget != DispatchTarget::CURRENT) {
+      Dispatcher<Impl, /* HasThisArg */ false, Args...>::template Run<Traits>(
+          cls, Method, env, args...);
+      return;
+    }
+
+    (*Method)(TypeAdapter<Args>::ToNative(env, args)...);
+  }
+
+  // Void static method with class reference
+  template <ReturnTypeForVoidStatic (*Method)(const Class::LocalRef&, Args...)>
+  static MOZ_JNICALL void Wrap(JNIEnv* env, jclass cls,
+                               typename TypeAdapter<Args>::JNIType... args) {
+    MOZ_ASSERT_JNI_THREAD(Traits::callingThread);
+
+    if (Traits::dispatchTarget != DispatchTarget::CURRENT) {
+      Dispatcher<Impl, /* HasThisArg */ true, Args...>::template Run<Traits>(
+          cls, Method, env, args...);
+      return;
+    }
+
+    auto clazz = Class::LocalRef::Adopt(env, cls);
+    (*Method)(clazz, TypeAdapter<Args>::ToNative(env, args)...);
+    clazz.Forget();
+  }
+};
+
+// Generate a JNINativeMethod from a native
+// method's traits class and a wrapped stub.
+template <class Traits, typename Ret, typename... Args>
+constexpr JNINativeMethod MakeNativeMethod(MOZ_JNICALL Ret (*stub)(JNIEnv*,
+                                                                   Args...)) {
+  return {Traits::name, Traits::signature, reinterpret_cast<void*>(stub)};
+}
+
+// Class inherited by implementing class.
+template <class Cls, class Impl>
+class NativeImpl {
+  typedef typename Cls::template Natives<Impl> Natives;
+
+  static bool sInited;
+
+ public:
+  static void Init() {
+    if (sInited) {
+      return;
+    }
+    const auto& ctx = typename Cls::Context();
+    ctx.Env()->RegisterNatives(
+        ctx.ClassRef(), Natives::methods,
+        sizeof(Natives::methods) / sizeof(Natives::methods[0]));
+    MOZ_CATCH_JNI_EXCEPTION(ctx.Env());
+    sInited = true;
+  }
+
+ protected:
+  // Associate a C++ instance with a Java instance.
+  static void AttachNative(const typename Cls::LocalRef& instance,
+                           SupportsWeakPtr* ptr) {
+    static_assert(NativePtrPicker<Impl>::value == NativePtrType::WEAK_INTRUSIVE,
+                  "Use another AttachNative for non-WeakPtr usage");
+    return NativePtrTraits<Impl>::Set(instance, static_cast<Impl*>(ptr));
+  }
+
+  static void AttachNative(const typename Cls::LocalRef& instance,
+                           UniquePtr<Impl>&& ptr) {
+    static_assert(NativePtrPicker<Impl>::value == NativePtrType::OWNING,
+                  "Use another AttachNative for WeakPtr or RefPtr usage");
+    return NativePtrTraits<Impl>::Set(instance, std::move(ptr));
+  }
+
+  static void AttachNative(const typename Cls::LocalRef& instance, Impl* ptr) {
+    static_assert(NativePtrPicker<Impl>::value == NativePtrType::REFPTR,
+                  "Use another AttachNative for non-RefPtr usage");
+    return NativePtrTraits<Impl>::Set(instance, ptr);
+  }
+
+  // Get the C++ instance associated with a Java instance.
+  // There is always a pending exception if the return value is nullptr.
+  static decltype(auto) GetNative(const typename Cls::LocalRef& instance) {
+    return NativePtrTraits<Impl>::Get(instance);
+  }
+
+  static void DisposeNative(const typename Cls::LocalRef& instance) {
+    NativePtrTraits<Impl>::Clear(instance);
+  }
+
+  NativeImpl() {
+    // Initialize on creation if not already initialized.
+    Init();
+  }
+};
+
+// Define static member.
+template <class C, class I>
+bool NativeImpl<C, I>::sInited;
+
+}  // namespace jni
+}  // namespace mozilla
+
+#endif  // mozilla_jni_Natives_h__
diff --git a/widget/android/jni/NativesInlines.h b/widget/android/jni/NativesInlines.h
new file mode 100644
index 0000000000..858b677715
--- /dev/null
+++ b/widget/android/jni/NativesInlines.h
@@ -0,0 +1,116 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Natives.h"
+
+#include "mozilla/MozPromise.h"
+
+namespace mozilla::jni {
+
+namespace details {
+
+/**
+ * When a NativeWeakPtr is detached from its owning Java object, the calling
+ * thread invokes the implementation's OnWeakNonIntrusiveDetach to perform
+ * cleanup. We complete the remainder of the cleanup sequence on the Gecko
+ * main thread by expecting OnWeakNonIntrusiveDetach implementations to invoke
+ * this Runnable before exiting. It will move itself to the main thread if it
+ * is not already there.
+ */
+template <typename NativeImpl>
+class NativeWeakPtrDetachRunnable final : public Runnable {
+ public:
+  NativeWeakPtrDetachRunnable(
+      already_AddRefed<detail::NativeWeakPtrControlBlock<NativeImpl>> aCtlBlock,
+      const Object::LocalRef& aOwner,
+      typename NativeWeakPtrControlBlockStorageTraits<NativeImpl>::Type
+          aNativeImpl)
+      : Runnable("mozilla::jni::detail::NativeWeakPtrDetachRunnable"),
+        mCtlBlock(aCtlBlock),
+        mOwner(aOwner),
+        mNativeImpl(std::move(aNativeImpl)),
+        mHasRun(false) {
+    MOZ_RELEASE_ASSERT(!!mCtlBlock);
+    MOZ_RELEASE_ASSERT(!!mNativeImpl);
+  }
+
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(NativeWeakPtrDetachRunnable, Runnable)
+
+  NS_IMETHOD Run() override {
+    mHasRun = true;
+
+    if (!NS_IsMainThread()) {
+      NS_DispatchToMainThread(this);
+      return NS_OK;
+    }
+
+    // Get the owner object's native implementation
+    auto owner = ToLocalRef(mOwner);
+    auto attachedNativeImpl = NativePtrTraits<NativeImpl>::Get(owner);
+    MOZ_RELEASE_ASSERT(!!attachedNativeImpl);
+
+    // NativePtrTraits::ClearFinish cleans out the JNIObject's handle, which
+    // obviously we don't want to attempt unless that handle still points to
+    // our native implementation.
+    if (attachedNativeImpl->IsSame(mCtlBlock)) {
+      NativePtrTraits<NativeImpl>::ClearFinish(owner);
+    }
+
+    // Now we destroy that native object.
+    mNativeImpl = nullptr;
+    mHolder.Resolve(true, __func__);
+    return NS_OK;
+  }
+
+  RefPtr<DetachPromise> GetPromise() { return mHolder.Ensure(__func__); }
+
+ private:
+  ~NativeWeakPtrDetachRunnable() {
+    // Guard against somebody forgetting to call this runnable.
+    MOZ_RELEASE_ASSERT(mHasRun, "You must run/dispatch this runnable!");
+  }
+
+ private:
+  RefPtr<detail::NativeWeakPtrControlBlock<NativeImpl>> mCtlBlock;
+  Object::GlobalRef mOwner;
+  MozPromiseHolder<DetachPromise> mHolder;
+  typename NativeWeakPtrControlBlockStorageTraits<NativeImpl>::Type mNativeImpl;
+  bool mHasRun;
+};
+
+}  // namespace details
+
+template <typename NativeImpl>
+RefPtr<DetachPromise> NativeWeakPtr<NativeImpl>::Detach() {
+  if (!IsAttached()) {
+    // Never attached to begin with; no-op
+    return DetachPromise::CreateAndResolve(true, __func__);
+  }
+
+  auto native = mCtlBlock->Clear();
+  if (!native) {
+    // Detach already in progress
+    return DetachPromise::CreateAndResolve(true, __func__);
+  }
+
+  Object::LocalRef owner(mCtlBlock->GetJavaOwner());
+  MOZ_RELEASE_ASSERT(!!owner);
+
+  // Save the raw pointer before we move native into the runnable so that we
+  // may call OnWeakNonIntrusiveDetach on it even after moving native into
+  // the runnable.
+  NativeImpl* rawImpl =
+      detail::NativeWeakPtrControlBlock<NativeImpl>::StorageTraits::AsRaw(
+          native);
+  RefPtr<details::NativeWeakPtrDetachRunnable<NativeImpl>> runnable =
+      new details::NativeWeakPtrDetachRunnable<NativeImpl>(
+          mCtlBlock.forget(), owner, std::move(native));
+  RefPtr<DetachPromise> promise = runnable->GetPromise();
+  rawImpl->OnWeakNonIntrusiveDetach(runnable.forget());
+  return promise;
+}
+
+}  // namespace mozilla::jni
diff --git a/widget/android/jni/Refs.h b/widget/android/jni/Refs.h
new file mode 100644
index 0000000000..29812fe6a5
--- /dev/null
+++ b/widget/android/jni/Refs.h
@@ -0,0 +1,1135 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_jni_Refs_h__
+#define mozilla_jni_Refs_h__
+
+#include <jni.h>
+
+#include <utility>
+
+#include "mozilla/fallible.h"
+#include "mozilla/jni/Utils.h"
+#include "mozilla/jni/TypeAdapter.h"
+#include "nsError.h"  // for nsresult
+#include "nsString.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+namespace jni {
+
+// Wrapped object reference (e.g. jobject, jclass, etc...)
+template <class Cls, typename JNIType>
+class Ref;
+// Represents a calling context for JNI methods.
+template <class Cls, typename JNIType>
+class Context;
+// Wrapped local reference that inherits from Ref.
+template <class Cls>
+class LocalRef;
+// Wrapped global reference that inherits from Ref.
+template <class Cls>
+class GlobalRef;
+// Wrapped weak reference that inherits from Ref.
+template <class Cls>
+class WeakRef;
+// Wrapped dangling reference that's owned by someone else.
+template <class Cls>
+class DependentRef;
+
+// Class to hold the native types of a method's arguments.
+// For example, if a method has signature (ILjava/lang/String;)V,
+// its arguments class would be jni::Args<int32_t, jni::String::Param>
+template <typename...>
+struct Args {};
+
+class Object;
+
+// Base class for Ref and its specializations.
+template <class Cls, typename Type>
+class Ref {
+  template <class C, typename T>
+  friend class Ref;
+
+  using Self = Ref<Cls, Type>;
+  using bool_type = void (Self::*)() const;
+  void non_null_reference() const {}
+
+  // A Cls-derivative that allows copying
+  // (e.g. when acting as a return value).
+  struct CopyableCtx : public Context<Cls, Type> {
+    CopyableCtx(JNIEnv* env, Type instance)
+        : Context<Cls, Type>(env, instance) {}
+
+    CopyableCtx(const CopyableCtx& cls)
+        : Context<Cls, Type>(cls.Env(), cls.Get()) {}
+  };
+
+  // Private copy constructor so that there's no danger of assigning a
+  // temporary LocalRef/GlobalRef to a Ref, and potentially use the Ref
+  // after the source had been freed.
+  Ref(const Ref&) = default;
+
+ protected:
+  static JNIEnv* FindEnv() {
+    return Cls::callingThread == CallingThread::GECKO ? GetGeckoThreadEnv()
+                                                      : GetEnvForThread();
+  }
+
+  Type mInstance;
+
+  // Protected jobject constructor because outside code should be using
+  // Ref::From. Using Ref::From makes it very easy to see which code is using
+  // raw JNI types for future refactoring.
+  explicit Ref(Type instance) : mInstance(instance) {}
+
+ public:
+  using JNIType = Type;
+
+  class AutoLock {
+    friend class Ref<Cls, Type>;
+
+    JNIEnv* const mEnv;
+    Type mInstance;
+
+    explicit AutoLock(Type aInstance)
+        : mEnv(FindEnv()), mInstance(mEnv->NewLocalRef(aInstance)) {
+      mEnv->MonitorEnter(mInstance);
+      MOZ_CATCH_JNI_EXCEPTION(mEnv);
+    }
+
+   public:
+    AutoLock(AutoLock&& aOther)
+        : mEnv(aOther.mEnv), mInstance(aOther.mInstance) {
+      aOther.mInstance = nullptr;
+    }
+
+    ~AutoLock() { Unlock(); }
+
+    void Unlock() {
+      if (mInstance) {
+        mEnv->MonitorExit(mInstance);
+        mEnv->DeleteLocalRef(mInstance);
+        MOZ_CATCH_JNI_EXCEPTION(mEnv);
+        mInstance = nullptr;
+      }
+    }
+  };
+
+  // Construct a Ref form a raw JNI reference.
+  static Ref<Cls, Type> From(JNIType obj) { return Ref<Cls, Type>(obj); }
+
+  // Construct a Ref form a generic object reference.
+  static Ref<Cls, Type> From(const Ref<Object, jobject>& obj) {
+    return Ref<Cls, Type>(JNIType(obj.Get()));
+  }
+
+  MOZ_IMPLICIT Ref(decltype(nullptr)) : mInstance(nullptr) {}
+
+  // Get the raw JNI reference.
+  JNIType Get() const { return mInstance; }
+
+  template <class T>
+  bool IsInstanceOf() const {
+    return FindEnv()->IsInstanceOf(mInstance, typename T::Context().ClassRef());
+  }
+
+  template <class T>
+  typename T::Ref Cast() const {
+#ifdef MOZ_CHECK_JNI
+    MOZ_RELEASE_ASSERT(FindEnv()->IsAssignableFrom(
+        Context<Cls, Type>().ClassRef(), typename T::Context().ClassRef()));
+#endif
+    return T::Ref::From(*this);
+  }
+
+  AutoLock Lock() const { return AutoLock(mInstance); }
+
+  bool operator==(const Ref& other) const {
+    // Treat two references of the same object as being the same.
+    return mInstance == other.mInstance ||
+           JNI_FALSE != FindEnv()->IsSameObject(mInstance, other.mInstance);
+  }
+
+  bool operator!=(const Ref& other) const { return !operator==(other); }
+
+  bool operator==(decltype(nullptr)) const { return !mInstance; }
+
+  bool operator!=(decltype(nullptr)) const { return !!mInstance; }
+
+  CopyableCtx operator->() const { return CopyableCtx(FindEnv(), mInstance); }
+
+  CopyableCtx operator*() const { return operator->(); }
+
+  // Any ref can be cast to an object ref.
+  operator Ref<Object, jobject>() const {
+    return Ref<Object, jobject>(mInstance);
+  }
+
+  // Null checking (e.g. !!ref) using the safe-bool idiom.
+  operator bool_type() const {
+    return mInstance ? &Self::non_null_reference : nullptr;
+  }
+
+  // We don't allow implicit conversion to jobject because that can lead
+  // to easy mistakes such as assigning a temporary LocalRef to a jobject,
+  // and using the jobject after the LocalRef has been freed.
+
+  // We don't allow explicit conversion, to make outside code use Ref::Get.
+  // Using Ref::Get makes it very easy to see which code is using raw JNI
+  // types to make future refactoring easier.
+
+  // operator JNIType() const = delete;
+};
+
+// Represents a calling context for JNI methods.
+template <class Cls, typename Type>
+class Context : public Ref<Cls, Type> {
+  using Ref = jni::Ref<Cls, Type>;
+
+  static jclass sClassRef;  // global reference
+
+ protected:
+  JNIEnv* const mEnv;
+
+ public:
+  Context() : Ref(nullptr), mEnv(Ref::FindEnv()) {}
+
+  Context(JNIEnv* env, Type instance) : Ref(instance), mEnv(env) {}
+
+  jclass ClassRef() const {
+    if (!sClassRef) {
+      const jclass cls = GetClassRef(mEnv, Cls::name);
+      sClassRef = jclass(mEnv->NewGlobalRef(cls));
+      mEnv->DeleteLocalRef(cls);
+    }
+    return sClassRef;
+  }
+
+  JNIEnv* Env() const { return mEnv; }
+
+  template <class T>
+  bool IsInstanceOf() const {
+    return mEnv->IsInstanceOf(Ref::mInstance,
+                              typename T::Context(mEnv, nullptr).ClassRef());
+  }
+
+  bool operator==(const Ref& other) const {
+    // Treat two references of the same object as being the same.
+    return Ref::mInstance == other.Get() ||
+           JNI_FALSE != mEnv->IsSameObject(Ref::mInstance, other.Get());
+  }
+
+  bool operator!=(const Ref& other) const { return !operator==(other); }
+
+  bool operator==(decltype(nullptr)) const { return !Ref::mInstance; }
+
+  bool operator!=(decltype(nullptr)) const { return !!Ref::mInstance; }
+
+  Cls operator->() const {
+    MOZ_ASSERT(Ref::mInstance, "Null jobject");
+    return Cls(*this);
+  }
+
+  const Context<Cls, Type>& operator*() const { return *this; }
+};
+
+template <class C, typename T>
+jclass Context<C, T>::sClassRef;
+
+template <class Cls, typename Type = jobject>
+class ObjectBase {
+ protected:
+  const jni::Context<Cls, Type>& mCtx;
+
+  jclass ClassRef() const { return mCtx.ClassRef(); }
+  JNIEnv* Env() const { return mCtx.Env(); }
+  Type Instance() const { return mCtx.Get(); }
+
+ public:
+  using Ref = jni::Ref<Cls, Type>;
+  using Context = jni::Context<Cls, Type>;
+  using LocalRef = jni::LocalRef<Cls>;
+  using GlobalRef = jni::GlobalRef<Cls>;
+  using WeakRef = jni::WeakRef<Cls>;
+  using Param = const Ref&;
+
+  static const CallingThread callingThread = CallingThread::ANY;
+  static const char name[];
+
+  explicit ObjectBase(const Context& ctx) : mCtx(ctx) {}
+
+  Cls* operator->() { return static_cast<Cls*>(this); }
+};
+
+// Binding for a plain jobject.
+class Object : public ObjectBase<Object, jobject> {
+ public:
+  explicit Object(const Context& ctx) : ObjectBase<Object, jobject>(ctx) {}
+};
+
+// Binding for a built-in object reference other than jobject.
+template <typename T>
+class TypedObject : public ObjectBase<TypedObject<T>, T> {
+ public:
+  explicit TypedObject(const Context<TypedObject<T>, T>& ctx)
+      : ObjectBase<TypedObject<T>, T>(ctx) {}
+};
+
+// Binding for a boxed primitive object.
+template <typename T>
+class BoxedObject : public ObjectBase<BoxedObject<T>, jobject> {
+ public:
+  explicit BoxedObject(const Context<BoxedObject<T>, jobject>& ctx)
+      : ObjectBase<BoxedObject<T>, jobject>(ctx) {}
+};
+
+template <>
+const char ObjectBase<Object, jobject>::name[];
+template <>
+const char ObjectBase<TypedObject<jstring>, jstring>::name[];
+template <>
+const char ObjectBase<TypedObject<jclass>, jclass>::name[];
+template <>
+const char ObjectBase<TypedObject<jthrowable>, jthrowable>::name[];
+template <>
+const char ObjectBase<BoxedObject<jboolean>, jobject>::name[];
+template <>
+const char ObjectBase<BoxedObject<jbyte>, jobject>::name[];
+template <>
+const char ObjectBase<BoxedObject<jchar>, jobject>::name[];
+template <>
+const char ObjectBase<BoxedObject<jshort>, jobject>::name[];
+template <>
+const char ObjectBase<BoxedObject<jint>, jobject>::name[];
+template <>
+const char ObjectBase<BoxedObject<jlong>, jobject>::name[];
+template <>
+const char ObjectBase<BoxedObject<jfloat>, jobject>::name[];
+template <>
+const char ObjectBase<BoxedObject<jdouble>, jobject>::name[];
+template <>
+const char ObjectBase<TypedObject<jbooleanArray>, jbooleanArray>::name[];
+template <>
+const char ObjectBase<TypedObject<jbyteArray>, jbyteArray>::name[];
+template <>
+const char ObjectBase<TypedObject<jcharArray>, jcharArray>::name[];
+template <>
+const char ObjectBase<TypedObject<jshortArray>, jshortArray>::name[];
+template <>
+const char ObjectBase<TypedObject<jintArray>, jintArray>::name[];
+template <>
+const char ObjectBase<TypedObject<jlongArray>, jlongArray>::name[];
+template <>
+const char ObjectBase<TypedObject<jfloatArray>, jfloatArray>::name[];
+template <>
+const char ObjectBase<TypedObject<jdoubleArray>, jdoubleArray>::name[];
+template <>
+const char ObjectBase<TypedObject<jobjectArray>, jobjectArray>::name[];
+
+// Define bindings for built-in types.
+using String = TypedObject<jstring>;
+using Class = TypedObject<jclass>;
+using Throwable = TypedObject<jthrowable>;
+
+using Boolean = BoxedObject<jboolean>;
+using Byte = BoxedObject<jbyte>;
+using Character = BoxedObject<jchar>;
+using Short = BoxedObject<jshort>;
+using Integer = BoxedObject<jint>;
+using Long = BoxedObject<jlong>;
+using Float = BoxedObject<jfloat>;
+using Double = BoxedObject<jdouble>;
+
+using BooleanArray = TypedObject<jbooleanArray>;
+using ByteArray = TypedObject<jbyteArray>;
+using CharArray = TypedObject<jcharArray>;
+using ShortArray = TypedObject<jshortArray>;
+using IntArray = TypedObject<jintArray>;
+using LongArray = TypedObject<jlongArray>;
+using FloatArray = TypedObject<jfloatArray>;
+using DoubleArray = TypedObject<jdoubleArray>;
+using ObjectArray = TypedObject<jobjectArray>;
+
+namespace detail {
+
+// See explanation in LocalRef.
+template <class Cls>
+struct GenericObject {
+  using Type = Object;
+};
+template <>
+struct GenericObject<Object> {
+  struct Type {
+    using Ref = jni::Ref<Type, jobject>;
+    using Context = jni::Context<Type, jobject>;
+  };
+};
+template <class Cls>
+struct GenericLocalRef {
+  template <class C>
+  struct Type : jni::Object {};
+};
+template <>
+struct GenericLocalRef<Object> {
+  template <class C>
+  using Type = jni::LocalRef<C>;
+};
+
+}  // namespace detail
+
+template <class Cls>
+class LocalRef : public Cls::Context {
+  template <class C>
+  friend class LocalRef;
+
+  using Ctx = typename Cls::Context;
+  using Ref = typename Cls::Ref;
+  using JNIType = typename Ref::JNIType;
+
+  // In order to be able to convert LocalRef<Object> to LocalRef<Cls>, we
+  // need constructors and copy assignment operators that take in a
+  // LocalRef<Object> argument. However, if Cls *is* Object, we would have
+  // duplicated constructors and operators with LocalRef<Object> arguments. To
+  // avoid this conflict, we use GenericObject, which is defined as Object for
+  // LocalRef<non-Object> and defined as a dummy class for LocalRef<Object>.
+  using GenericObject = typename detail::GenericObject<Cls>::Type;
+
+  // Similarly, GenericLocalRef is useed to convert LocalRef<Cls> to,
+  // LocalRef<Object>. It's defined as LocalRef<C> for Cls == Object,
+  // and defined as a dummy template class for Cls != Object.
+  template <class C>
+  using GenericLocalRef =
+      typename detail::GenericLocalRef<Cls>::template Type<C>;
+
+  static JNIType NewLocalRef(JNIEnv* env, JNIType obj) {
+    return JNIType(obj ? env->NewLocalRef(obj) : nullptr);
+  }
+
+  LocalRef(JNIEnv* env, JNIType instance) : Ctx(env, instance) {}
+
+  LocalRef& swap(LocalRef& other) {
+    auto instance = other.mInstance;
+    other.mInstance = Ctx::mInstance;
+    Ctx::mInstance = instance;
+    return *this;
+  }
+
+ public:
+  // Construct a LocalRef from a raw JNI local reference. Unlike Ref::From,
+  // LocalRef::Adopt returns a LocalRef that will delete the local reference
+  // when going out of scope.
+  static LocalRef Adopt(JNIType instance) {
+    return LocalRef(Ref::FindEnv(), instance);
+  }
+
+  static LocalRef Adopt(JNIEnv* env, JNIType instance) {
+    return LocalRef(env, instance);
+  }
+
+  // Copy constructor.
+  LocalRef(const LocalRef<Cls>& ref)
+      : Ctx(ref.mEnv, NewLocalRef(ref.mEnv, ref.mInstance)) {}
+
+  // Move constructor.
+  LocalRef(LocalRef<Cls>&& ref) : Ctx(ref.mEnv, ref.mInstance) {
+    ref.mInstance = nullptr;
+  }
+
+  explicit LocalRef(JNIEnv* env = Ref::FindEnv()) : Ctx(env, nullptr) {}
+
+  // Construct a LocalRef from any Ref,
+  // which means creating a new local reference.
+  MOZ_IMPLICIT LocalRef(const Ref& ref) : Ctx(Ref::FindEnv(), nullptr) {
+    Ctx::mInstance = NewLocalRef(Ctx::mEnv, ref.Get());
+  }
+
+  LocalRef(JNIEnv* env, const Ref& ref)
+      : Ctx(env, NewLocalRef(env, ref.Get())) {}
+
+  // Move a LocalRef<Object> into a LocalRef<Cls> without
+  // creating/deleting local references.
+  MOZ_IMPLICIT LocalRef(LocalRef<GenericObject>&& ref)
+      : Ctx(ref.mEnv, JNIType(ref.mInstance)) {
+    ref.mInstance = nullptr;
+  }
+
+  template <class C>
+  MOZ_IMPLICIT LocalRef(GenericLocalRef<C>&& ref)
+      : Ctx(ref.mEnv, ref.mInstance) {
+    ref.mInstance = nullptr;
+  }
+
+  // Implicitly converts nullptr to LocalRef.
+  MOZ_IMPLICIT LocalRef(decltype(nullptr)) : Ctx(Ref::FindEnv(), nullptr) {}
+
+  ~LocalRef() {
+    if (Ctx::mInstance) {
+      Ctx::mEnv->DeleteLocalRef(Ctx::mInstance);
+      Ctx::mInstance = nullptr;
+    }
+  }
+
+  // Get the raw JNI reference that can be used as a return value.
+  // Returns the same JNI type (jobject, jstring, etc.) as the underlying Ref.
+  typename Ref::JNIType Forget() {
+    const auto obj = Ctx::Get();
+    Ctx::mInstance = nullptr;
+    return obj;
+  }
+
+  LocalRef<Cls>& operator=(LocalRef<Cls> ref) & { return swap(ref); }
+
+  LocalRef<Cls>& operator=(const Ref& ref) & {
+    LocalRef<Cls> newRef(Ctx::mEnv, ref);
+    return swap(newRef);
+  }
+
+  LocalRef<Cls>& operator=(LocalRef<GenericObject>&& ref) & {
+    LocalRef<Cls> newRef(std::move(ref));
+    return swap(newRef);
+  }
+
+  template <class C>
+  LocalRef<Cls>& operator=(GenericLocalRef<C>&& ref) & {
+    LocalRef<Cls> newRef(std::move(ref));
+    return swap(newRef);
+  }
+
+  LocalRef<Cls>& operator=(decltype(nullptr)) & {
+    LocalRef<Cls> newRef(Ctx::mEnv, nullptr);
+    return swap(newRef);
+  }
+};
+
+template <class Cls>
+class GlobalRef : public Cls::Ref {
+  using Ref = typename Cls::Ref;
+  using JNIType = typename Ref::JNIType;
+
+  static JNIType NewGlobalRef(JNIEnv* env, JNIType instance) {
+    return JNIType(instance ? env->NewGlobalRef(instance) : nullptr);
+  }
+
+  GlobalRef& swap(GlobalRef& other) {
+    auto instance = other.mInstance;
+    other.mInstance = Ref::mInstance;
+    Ref::mInstance = instance;
+    return *this;
+  }
+
+ public:
+  GlobalRef() : Ref(nullptr) {}
+
+  // Copy constructor
+  GlobalRef(const GlobalRef& ref)
+      : Ref(NewGlobalRef(GetEnvForThread(), ref.mInstance)) {}
+
+  // Move constructor
+  GlobalRef(GlobalRef&& ref) : Ref(ref.mInstance) { ref.mInstance = nullptr; }
+
+  MOZ_IMPLICIT GlobalRef(const Ref& ref)
+      : Ref(NewGlobalRef(GetEnvForThread(), ref.Get())) {}
+
+  GlobalRef(JNIEnv* env, const Ref& ref) : Ref(NewGlobalRef(env, ref.Get())) {}
+
+  MOZ_IMPLICIT GlobalRef(const LocalRef<Cls>& ref)
+      : Ref(NewGlobalRef(ref.Env(), ref.Get())) {}
+
+  // Implicitly converts nullptr to GlobalRef.
+  MOZ_IMPLICIT GlobalRef(decltype(nullptr)) : Ref(nullptr) {}
+
+  ~GlobalRef() {
+    if (Ref::mInstance) {
+      Clear(GetEnvForThread());
+    }
+  }
+
+  // Get the raw JNI reference that can be used as a return value.
+  // Returns the same JNI type (jobject, jstring, etc.) as the underlying Ref.
+  typename Ref::JNIType Forget() {
+    const auto obj = Ref::Get();
+    Ref::mInstance = nullptr;
+    return obj;
+  }
+
+  void Clear(JNIEnv* env) {
+    if (Ref::mInstance) {
+      env->DeleteGlobalRef(Ref::mInstance);
+      Ref::mInstance = nullptr;
+    }
+  }
+
+  GlobalRef<Cls>& operator=(GlobalRef<Cls> ref) & { return swap(ref); }
+
+  GlobalRef<Cls>& operator=(const Ref& ref) & {
+    GlobalRef<Cls> newRef(ref);
+    return swap(newRef);
+  }
+
+  GlobalRef<Cls>& operator=(const LocalRef<Cls>& ref) & {
+    GlobalRef<Cls> newRef(ref);
+    return swap(newRef);
+  }
+
+  GlobalRef<Cls>& operator=(decltype(nullptr)) & {
+    GlobalRef<Cls> newRef(nullptr);
+    return swap(newRef);
+  }
+};
+
+template <class Cls>
+class WeakRef : public Ref<Cls, jweak> {
+  using Ref = Ref<Cls, jweak>;
+  using JNIType = typename Ref::JNIType;
+
+  static JNIType NewWeakRef(JNIEnv* env, JNIType instance) {
+    return JNIType(instance ? env->NewWeakGlobalRef(instance) : nullptr);
+  }
+
+  WeakRef& swap(WeakRef& other) {
+    auto instance = other.mInstance;
+    other.mInstance = Ref::mInstance;
+    Ref::mInstance = instance;
+    return *this;
+  }
+
+ public:
+  WeakRef() : Ref(nullptr) {}
+
+  // Copy constructor
+  WeakRef(const WeakRef& ref)
+      : Ref(NewWeakRef(GetEnvForThread(), ref.mInstance)) {}
+
+  // Move constructor
+  WeakRef(WeakRef&& ref) : Ref(ref.mInstance) { ref.mInstance = nullptr; }
+
+  MOZ_IMPLICIT WeakRef(const Ref& ref)
+      : Ref(NewWeakRef(GetEnvForThread(), ref.Get())) {}
+
+  WeakRef(JNIEnv* env, const Ref& ref) : Ref(NewWeakRef(env, ref.Get())) {}
+
+  MOZ_IMPLICIT WeakRef(const LocalRef<Cls>& ref)
+      : Ref(NewWeakRef(ref.Env(), ref.Get())) {}
+
+  // Implicitly converts nullptr to WeakRef.
+  MOZ_IMPLICIT WeakRef(decltype(nullptr)) : Ref(nullptr) {}
+
+  ~WeakRef() {
+    if (Ref::mInstance) {
+      Clear(GetEnvForThread());
+    }
+  }
+
+  // Get the raw JNI reference that can be used as a return value.
+  // Returns the same JNI type (jobject, jstring, etc.) as the underlying Ref.
+  typename Ref::JNIType Forget() {
+    const auto obj = Ref::Get();
+    Ref::mInstance = nullptr;
+    return obj;
+  }
+
+  void Clear(JNIEnv* env) {
+    if (Ref::mInstance) {
+      env->DeleteWeakGlobalRef(Ref::mInstance);
+      Ref::mInstance = nullptr;
+    }
+  }
+
+  WeakRef<Cls>& operator=(WeakRef<Cls> ref) & { return swap(ref); }
+
+  WeakRef<Cls>& operator=(const Ref& ref) & {
+    WeakRef<Cls> newRef(ref);
+    return swap(newRef);
+  }
+
+  WeakRef<Cls>& operator=(const LocalRef<Cls>& ref) & {
+    WeakRef<Cls> newRef(ref);
+    return swap(newRef);
+  }
+
+  WeakRef<Cls>& operator=(decltype(nullptr)) & {
+    WeakRef<Cls> newRef(nullptr);
+    return swap(newRef);
+  }
+
+  void operator->() const = delete;
+  void operator*() const = delete;
+};
+
+template <class Cls>
+class DependentRef : public Cls::Ref {
+  using Ref = typename Cls::Ref;
+
+ public:
+  explicit DependentRef(typename Ref::JNIType instance) : Ref(instance) {}
+
+  DependentRef(const DependentRef& ref) : Ref(ref.Get()) {}
+};
+
+class StringParam;
+
+template <>
+class TypedObject<jstring> : public ObjectBase<TypedObject<jstring>, jstring> {
+  using Base = ObjectBase<TypedObject<jstring>, jstring>;
+
+ public:
+  using Param = const StringParam&;
+
+  explicit TypedObject(const Context& ctx) : Base(ctx) {}
+
+  size_t Length() const {
+    const size_t ret = Base::Env()->GetStringLength(Base::Instance());
+    MOZ_CATCH_JNI_EXCEPTION(Base::Env());
+    return ret;
+  }
+
+  nsString ToString() const {
+    const jchar* const str =
+        Base::Env()->GetStringChars(Base::Instance(), nullptr);
+    const jsize len = Base::Env()->GetStringLength(Base::Instance());
+
+    nsString result(reinterpret_cast<const char16_t*>(str), len);
+    Base::Env()->ReleaseStringChars(Base::Instance(), str);
+    return result;
+  }
+
+  nsCString ToCString() const { return NS_ConvertUTF16toUTF8(ToString()); }
+
+  // Convert jstring to a nsString.
+  operator nsString() const { return ToString(); }
+
+  // Convert jstring to a nsCString.
+  operator nsCString() const { return ToCString(); }
+};
+
+// Define a custom parameter type for String,
+// which accepts both String::Ref and nsAString/nsACString
+class StringParam : public String::Ref {
+  using Ref = String::Ref;
+
+ private:
+  // Not null if we should delete ref on destruction.
+  JNIEnv* const mEnv;
+
+  static jstring GetString(JNIEnv* env, const nsAString& str) {
+    const jstring result = env->NewString(
+        reinterpret_cast<const jchar*>(str.BeginReading()), str.Length());
+    if (!result) {
+      NS_ABORT_OOM(str.Length() * sizeof(char16_t));
+    }
+    MOZ_CATCH_JNI_EXCEPTION(env);
+    return result;
+  }
+
+  static jstring GetString(JNIEnv* env, const nsAString& str,
+                           const fallible_t&) {
+    const jstring result = env->NewString(
+        reinterpret_cast<const jchar*>(str.BeginReading()), str.Length());
+    if (env->ExceptionCheck()) {
+#ifdef MOZ_CHECK_JNI
+      env->ExceptionDescribe();
+#endif
+      env->ExceptionClear();
+    }
+    return result;
+  }
+
+  static jstring GetString(JNIEnv* env, const nsACString& str,
+                           const fallible_t& aFallible) {
+    nsAutoString utf16;
+    if (!CopyUTF8toUTF16(str, utf16, aFallible)) {
+      return nullptr;
+    }
+    return GetString(env, utf16, aFallible);
+  }
+
+ public:
+  MOZ_IMPLICIT StringParam(decltype(nullptr)) : Ref(nullptr), mEnv(nullptr) {}
+
+  MOZ_IMPLICIT StringParam(const Ref& ref) : Ref(ref.Get()), mEnv(nullptr) {}
+
+  MOZ_IMPLICIT StringParam(const nsAString& str, JNIEnv* env = Ref::FindEnv())
+      : Ref(GetString(env, str)), mEnv(env) {}
+
+  MOZ_IMPLICIT StringParam(const nsAString& str, JNIEnv* env,
+                           const fallible_t& aFallible)
+      : Ref(GetString(env, str, aFallible)), mEnv(env) {}
+
+  MOZ_IMPLICIT StringParam(const nsLiteralString& str,
+                           JNIEnv* env = Ref::FindEnv())
+      : Ref(GetString(env, str)), mEnv(env) {}
+
+  MOZ_IMPLICIT StringParam(const char16_t* str, JNIEnv* env = Ref::FindEnv())
+      : Ref(GetString(env, nsDependentString(str))), mEnv(env) {}
+
+  MOZ_IMPLICIT StringParam(const nsACString& str, JNIEnv* env = Ref::FindEnv())
+      : Ref(GetString(env, NS_ConvertUTF8toUTF16(str))), mEnv(env) {}
+
+  MOZ_IMPLICIT StringParam(const nsACString& str, JNIEnv* env,
+                           const fallible_t& aFallible)
+      : Ref(GetString(env, str, aFallible)), mEnv(env) {}
+
+  MOZ_IMPLICIT StringParam(const nsLiteralCString& str,
+                           JNIEnv* env = Ref::FindEnv())
+      : Ref(GetString(env, NS_ConvertUTF8toUTF16(str))), mEnv(env) {}
+
+  MOZ_IMPLICIT StringParam(const char* str, JNIEnv* env = Ref::FindEnv())
+      : Ref(GetString(env, NS_ConvertUTF8toUTF16(str))), mEnv(env) {}
+
+  StringParam(StringParam&& other) : Ref(other.Get()), mEnv(other.mEnv) {
+    other.mInstance = nullptr;
+  }
+
+  ~StringParam() {
+    if (mEnv && Get()) {
+      mEnv->DeleteLocalRef(Get());
+    }
+  }
+
+  operator String::LocalRef() const {
+    // We can't return our existing ref because the returned
+    // LocalRef could be freed first, so we need a new local ref.
+    return String::LocalRef(mEnv ? mEnv : Ref::FindEnv(), *this);
+  }
+};
+
+namespace detail {
+template <typename T>
+struct TypeAdapter;
+}
+
+// Ref specialization for arrays.
+template <typename JNIType, class ElementType>
+class ArrayRefBase : public ObjectBase<TypedObject<JNIType>, JNIType> {
+ protected:
+  using Base = ObjectBase<TypedObject<JNIType>, JNIType>;
+
+ public:
+  explicit ArrayRefBase(const Context<TypedObject<JNIType>, JNIType>& ctx)
+      : Base(ctx) {}
+
+  static typename Base::LocalRef New(const ElementType* data, size_t length) {
+    using JNIElemType = typename detail::TypeAdapter<ElementType>::JNIType;
+    static_assert(sizeof(ElementType) == sizeof(JNIElemType),
+                  "Size of native type must match size of JNI type");
+    JNIEnv* const jenv = mozilla::jni::GetEnvForThread();
+    auto result = (jenv->*detail::TypeAdapter<ElementType>::NewArray)(length);
+    MOZ_CATCH_JNI_EXCEPTION(jenv);
+    (jenv->*detail::TypeAdapter<ElementType>::SetArray)(
+        result, jsize(0), length, reinterpret_cast<const JNIElemType*>(data));
+    MOZ_CATCH_JNI_EXCEPTION(jenv);
+    return Base::LocalRef::Adopt(jenv, result);
+  }
+
+  static typename Base::LocalRef New(const ElementType* data, size_t length,
+                                     const fallible_t&) {
+    using JNIElemType = typename detail::TypeAdapter<ElementType>::JNIType;
+    static_assert(sizeof(ElementType) == sizeof(JNIElemType),
+                  "Size of native type must match size of JNI type");
+    JNIEnv* const jenv = mozilla::jni::GetEnvForThread();
+    auto result = (jenv->*detail::TypeAdapter<ElementType>::NewArray)(length);
+    if (jenv->ExceptionCheck()) {
+      if (!IsOOMException(jenv)) {
+        // This exception isn't excepted due not to OOM. This is unrecoverable
+        // error.
+        MOZ_CATCH_JNI_EXCEPTION(jenv);
+      }
+#ifdef MOZ_CHECK_JNI
+      jenv->ExceptionDescribe();
+#endif
+      jenv->ExceptionClear();
+      return Base::LocalRef::Adopt(jenv, nullptr);
+    }
+    (jenv->*detail::TypeAdapter<ElementType>::SetArray)(
+        result, jsize(0), length, reinterpret_cast<const JNIElemType*>(data));
+    if (jenv->ExceptionCheck()) {
+      if (!IsOOMException(jenv)) {
+        // This exception isn't excepted due not to OOM. This is unrecoverable
+        // error.
+        MOZ_CATCH_JNI_EXCEPTION(jenv);
+      }
+#ifdef MOZ_CHECK_JNI
+      jenv->ExceptionDescribe();
+#endif
+      jenv->ExceptionClear();
+      jenv->DeleteLocalRef(result);
+      return Base::LocalRef::Adopt(jenv, nullptr);
+    }
+    return Base::LocalRef::Adopt(jenv, result);
+  }
+
+  size_t Length() const {
+    const size_t ret = Base::Env()->GetArrayLength(Base::Instance());
+    MOZ_CATCH_JNI_EXCEPTION(Base::Env());
+    return ret;
+  }
+
+  ElementType GetElement(size_t index) const {
+    using JNIElemType = typename detail::TypeAdapter<ElementType>::JNIType;
+    static_assert(sizeof(ElementType) == sizeof(JNIElemType),
+                  "Size of native type must match size of JNI type");
+
+    ElementType ret;
+    (Base::Env()->*detail::TypeAdapter<ElementType>::GetArray)(
+        Base::Instance(), jsize(index), 1,
+        reinterpret_cast<JNIElemType*>(&ret));
+    MOZ_CATCH_JNI_EXCEPTION(Base::Env());
+    return ret;
+  }
+
+  nsTArray<ElementType> GetElements() const {
+    using JNIElemType = typename detail::TypeAdapter<ElementType>::JNIType;
+    static_assert(sizeof(ElementType) == sizeof(JNIElemType),
+                  "Size of native type must match size of JNI type");
+
+    const size_t len = size_t(Base::Env()->GetArrayLength(Base::Instance()));
+
+    nsTArray<ElementType> array(len);
+    array.SetLength(len);
+    CopyTo(array.Elements(), len);
+    return array;
+  }
+
+  // returns number of elements copied
+  size_t CopyTo(ElementType* buffer, size_t size) const {
+    using JNIElemType = typename detail::TypeAdapter<ElementType>::JNIType;
+    static_assert(sizeof(ElementType) == sizeof(JNIElemType),
+                  "Size of native type must match size of JNI type");
+
+    const size_t len = size_t(Base::Env()->GetArrayLength(Base::Instance()));
+    const size_t amountToCopy = (len > size ? size : len);
+    (Base::Env()->*detail::TypeAdapter<ElementType>::GetArray)(
+        Base::Instance(), 0, jsize(amountToCopy),
+        reinterpret_cast<JNIElemType*>(buffer));
+    return amountToCopy;
+  }
+
+  ElementType operator[](size_t index) const { return GetElement(index); }
+
+  operator nsTArray<ElementType>() const { return GetElements(); }
+};
+
+#define DEFINE_PRIMITIVE_ARRAY_REF_HEADER(JNIType, ElementType)                \
+  template <>                                                                  \
+  class TypedObject<JNIType> : public ArrayRefBase<JNIType, ElementType> {     \
+   public:                                                                     \
+    explicit TypedObject(const Context& ctx)                                   \
+        : ArrayRefBase<JNIType, ElementType>(ctx) {}                           \
+    static typename Base::LocalRef From(const nsTArray<ElementType>& aArray) { \
+      return New(aArray.Elements(), aArray.Length());                          \
+    }
+
+#define DEFINE_PRIMITIVE_ARRAY_REF_FOOTER }
+
+#define DEFINE_PRIMITIVE_ARRAY_REF_FROM_IMPLICIT_CONVERSION(ElementType,     \
+                                                            ConvertFromType) \
+  static typename Base::LocalRef From(                                       \
+      const nsTArray<ConvertFromType>& aArray) {                             \
+    return New(reinterpret_cast<const ElementType*>(aArray.Elements()),      \
+               aArray.Length());                                             \
+  }
+
+#define DEFINE_PRIMITIVE_ARRAY_REF(JNIType, ElementType)  \
+  DEFINE_PRIMITIVE_ARRAY_REF_HEADER(JNIType, ElementType) \
+  DEFINE_PRIMITIVE_ARRAY_REF_FOOTER
+
+#define DEFINE_PRIMITIVE_ARRAY_REF_WITH_IMPLICIT_CONVERSION(           \
+    JNIType, ElementType, ConvertFromType)                             \
+  DEFINE_PRIMITIVE_ARRAY_REF_HEADER(JNIType, ElementType)              \
+  DEFINE_PRIMITIVE_ARRAY_REF_FROM_IMPLICIT_CONVERSION(ElementType,     \
+                                                      ConvertFromType) \
+  DEFINE_PRIMITIVE_ARRAY_REF_FOOTER
+
+DEFINE_PRIMITIVE_ARRAY_REF(jbooleanArray, bool);
+DEFINE_PRIMITIVE_ARRAY_REF_WITH_IMPLICIT_CONVERSION(jbyteArray, int8_t,
+                                                    uint8_t);
+DEFINE_PRIMITIVE_ARRAY_REF(jcharArray, char16_t);
+DEFINE_PRIMITIVE_ARRAY_REF_WITH_IMPLICIT_CONVERSION(jshortArray, int16_t,
+                                                    uint16_t);
+DEFINE_PRIMITIVE_ARRAY_REF_WITH_IMPLICIT_CONVERSION(jintArray, int32_t,
+                                                    uint32_t);
+DEFINE_PRIMITIVE_ARRAY_REF(jfloatArray, float);
+DEFINE_PRIMITIVE_ARRAY_REF_WITH_IMPLICIT_CONVERSION(jlongArray, int64_t,
+                                                    uint64_t);
+DEFINE_PRIMITIVE_ARRAY_REF(jdoubleArray, double);
+
+#undef DEFINE_PRIMITIVE_ARRAY_REF
+#undef DEFINE_PRIMITIVE_ARRAY_REF_WITH_IMPLICIT_CONVERSION
+#undef DEFINE_PRIMITIVE_ARRAY_HEADER
+#undef DEFINE_PRIMITIVE_ARRAY_FROM_IMPLICIT_CONVERSION
+#undef DEFINE_PRIMITIVE_ARRAY_FOOTER
+
+class ByteBuffer : public ObjectBase<ByteBuffer, jobject> {
+ public:
+  explicit ByteBuffer(const Context& ctx)
+      : ObjectBase<ByteBuffer, jobject>(ctx) {}
+
+  static LocalRef New(void* data, size_t capacity) {
+    JNIEnv* const env = GetEnvForThread();
+    const auto ret =
+        LocalRef::Adopt(env, env->NewDirectByteBuffer(data, jlong(capacity)));
+    MOZ_CATCH_JNI_EXCEPTION(env);
+    return ret;
+  }
+
+  static LocalRef New(void* data, size_t capacity, const fallible_t&) {
+    JNIEnv* const env = GetEnvForThread();
+    const jobject result = env->NewDirectByteBuffer(data, jlong(capacity));
+    if (env->ExceptionCheck()) {
+      if (!IsOOMException(env)) {
+        // This exception isn't excepted due not to OOM. This is unrecoverable
+        // error.
+        MOZ_CATCH_JNI_EXCEPTION(env);
+      }
+#ifdef MOZ_CHECK_JNI
+      env->ExceptionDescribe();
+#endif
+      env->ExceptionClear();
+      return LocalRef::Adopt(env, nullptr);
+    }
+    return LocalRef::Adopt(env, result);
+  }
+
+  void* Address() {
+    void* const ret = Env()->GetDirectBufferAddress(Instance());
+    MOZ_CATCH_JNI_EXCEPTION(Env());
+    return ret;
+  }
+
+  size_t Capacity() {
+    const size_t ret = size_t(Env()->GetDirectBufferCapacity(Instance()));
+    MOZ_CATCH_JNI_EXCEPTION(Env());
+    return ret;
+  }
+};
+
+template <>
+const char ObjectBase<ByteBuffer, jobject>::name[];
+
+template <>
+class TypedObject<jobjectArray>
+    : public ObjectBase<TypedObject<jobjectArray>, jobjectArray> {
+  using Base = ObjectBase<TypedObject<jobjectArray>, jobjectArray>;
+
+ public:
+  template <class Cls = Object>
+  static Base::LocalRef New(size_t length,
+                            typename Cls::Param initialElement = nullptr) {
+    JNIEnv* const env = GetEnvForThread();
+    jobjectArray array = env->NewObjectArray(
+        jsize(length), typename Cls::Context(env, nullptr).ClassRef(),
+        initialElement.Get());
+    MOZ_CATCH_JNI_EXCEPTION(env);
+    return Base::LocalRef::Adopt(env, array);
+  }
+
+  explicit TypedObject(const Context& ctx) : Base(ctx) {}
+
+  size_t Length() const {
+    const size_t ret = Base::Env()->GetArrayLength(Base::Instance());
+    MOZ_CATCH_JNI_EXCEPTION(Base::Env());
+    return ret;
+  }
+
+  Object::LocalRef GetElement(size_t index) const {
+    auto ret = Object::LocalRef::Adopt(
+        Base::Env(),
+        Base::Env()->GetObjectArrayElement(Base::Instance(), jsize(index)));
+    MOZ_CATCH_JNI_EXCEPTION(Base::Env());
+    return ret;
+  }
+
+  nsTArray<Object::LocalRef> GetElements() const {
+    const jsize len = size_t(Base::Env()->GetArrayLength(Base::Instance()));
+
+    nsTArray<Object::LocalRef> array((size_t(len)));
+    for (jsize i = 0; i < len; i++) {
+      array.AppendElement(Object::LocalRef::Adopt(
+          Base::Env(),
+          Base::Env()->GetObjectArrayElement(Base::Instance(), i)));
+      MOZ_CATCH_JNI_EXCEPTION(Base::Env());
+    }
+    return array;
+  }
+
+  Object::LocalRef operator[](size_t index) const { return GetElement(index); }
+
+  operator nsTArray<Object::LocalRef>() const { return GetElements(); }
+
+  void SetElement(size_t index, Object::Param element) const {
+    Base::Env()->SetObjectArrayElement(Base::Instance(), jsize(index),
+                                       element.Get());
+    MOZ_CATCH_JNI_EXCEPTION(Base::Env());
+  }
+};
+
+// Support conversion from LocalRef<T>* to LocalRef<Object>*:
+//   LocalRef<Foo> foo;
+//   Foo::GetFoo(&foo); // error because parameter type is LocalRef<Object>*.
+//   Foo::GetFoo(ReturnTo(&foo)); // OK because ReturnTo converts the argument.
+template <class Cls>
+class ReturnToLocal {
+ private:
+  LocalRef<Cls>* const localRef;
+  LocalRef<Object> objRef;
+
+ public:
+  explicit ReturnToLocal(LocalRef<Cls>* ref) : localRef(ref) {}
+  operator LocalRef<Object>*() { return &objRef; }
+
+  ~ReturnToLocal() {
+    if (objRef) {
+      *localRef = std::move(objRef);
+    }
+  }
+};
+
+template <class Cls>
+ReturnToLocal<Cls> ReturnTo(LocalRef<Cls>* ref) {
+  return ReturnToLocal<Cls>(ref);
+}
+
+// Support conversion from GlobalRef<T>* to LocalRef<Object/T>*:
+//   GlobalRef<Foo> foo;
+//   Foo::GetFoo(&foo); // error because parameter type is LocalRef<Foo>*.
+//   Foo::GetFoo(ReturnTo(&foo)); // OK because ReturnTo converts the argument.
+template <class Cls>
+class ReturnToGlobal {
+ private:
+  GlobalRef<Cls>* const globalRef;
+  LocalRef<Object> objRef;
+  LocalRef<Cls> clsRef;
+
+ public:
+  explicit ReturnToGlobal(GlobalRef<Cls>* ref) : globalRef(ref) {}
+  operator LocalRef<Object>*() { return &objRef; }
+  operator LocalRef<Cls>*() { return &clsRef; }
+
+  ~ReturnToGlobal() {
+    if (objRef) {
+      *globalRef = (clsRef = std::move(objRef));
+    } else if (clsRef) {
+      *globalRef = clsRef;
+    }
+  }
+};
+
+template <class Cls>
+ReturnToGlobal<Cls> ReturnTo(GlobalRef<Cls>* ref) {
+  return ReturnToGlobal<Cls>(ref);
+}
+
+// Make a LocalRef<T> from any other Ref<T>
+template <typename Cls, typename JNIType>
+LocalRef<Cls> ToLocalRef(const Ref<Cls, JNIType>& aRef) {
+  return LocalRef<Cls>(aRef);
+}
+
+}  // namespace jni
+}  // namespace mozilla
+
+#endif  // mozilla_jni_Refs_h__
diff --git a/widget/android/jni/TypeAdapter.h b/widget/android/jni/TypeAdapter.h
new file mode 100644
index 0000000000..5ab1e14bf5
--- /dev/null
+++ b/widget/android/jni/TypeAdapter.h
@@ -0,0 +1,71 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_jni_TypeAdapter_h__
+#define mozilla_jni_TypeAdapter_h__
+
+#include <jni.h>
+
+#include "mozilla/jni/Refs.h"
+
+namespace mozilla {
+namespace jni {
+namespace detail {
+
+// TypeAdapter specializations are the interfaces between native/C++ types such
+// as int32_t and JNI types such as jint. The template parameter T is the native
+// type, and each TypeAdapter specialization can have the following members:
+//
+//  * Call: JNIEnv member pointer for making a method call that returns T.
+//  * StaticCall: JNIEnv member pointer for making a static call that returns T.
+//  * Get: JNIEnv member pointer for getting a field of type T.
+//  * StaticGet: JNIEnv member pointer for getting a static field of type T.
+//  * Set: JNIEnv member pointer for setting a field of type T.
+//  * StaticGet: JNIEnv member pointer for setting a static field of type T.
+//  * ToNative: static function that converts the JNI type to the native type.
+//  * FromNative: static function that converts the native type to the JNI type.
+
+template <typename T>
+struct TypeAdapter;
+
+#define DEFINE_PRIMITIVE_TYPE_ADAPTER(NativeType, JNIType, JNIName)           \
+                                                                              \
+  template <>                                                                 \
+  struct TypeAdapter<NativeType> {                                            \
+    using JNI##Type = JNIType;                                                \
+                                                                              \
+    static constexpr auto Call = &JNIEnv::Call##JNIName##MethodA;             \
+    static constexpr auto StaticCall = &JNIEnv::CallStatic##JNIName##MethodA; \
+    static constexpr auto Get = &JNIEnv::Get##JNIName##Field;                 \
+    static constexpr auto StaticGet = &JNIEnv::GetStatic##JNIName##Field;     \
+    static constexpr auto Set = &JNIEnv::Set##JNIName##Field;                 \
+    static constexpr auto StaticSet = &JNIEnv::SetStatic##JNIName##Field;     \
+    static constexpr auto GetArray = &JNIEnv::Get##JNIName##ArrayRegion;      \
+    static constexpr auto SetArray = &JNIEnv::Set##JNIName##ArrayRegion;      \
+    static constexpr auto NewArray = &JNIEnv::New##JNIName##Array;            \
+                                                                              \
+    static JNIType FromNative(JNIEnv*, NativeType val) {                      \
+      return static_cast<JNIType>(val);                                       \
+    }                                                                         \
+    static NativeType ToNative(JNIEnv*, JNIType val) {                        \
+      return static_cast<NativeType>(val);                                    \
+    }                                                                         \
+  }
+
+DEFINE_PRIMITIVE_TYPE_ADAPTER(bool, jboolean, Boolean);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(int8_t, jbyte, Byte);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(char16_t, jchar, Char);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(int16_t, jshort, Short);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(int32_t, jint, Int);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(int64_t, jlong, Long);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(float, jfloat, Float);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(double, jdouble, Double);
+
+#undef DEFINE_PRIMITIVE_TYPE_ADAPTER
+
+}  // namespace detail
+}  // namespace jni
+}  // namespace mozilla
+
+#endif  // mozilla_jni_Types_h__
diff --git a/widget/android/jni/Types.h b/widget/android/jni/Types.h
new file mode 100644
index 0000000000..1fe5fa4400
--- /dev/null
+++ b/widget/android/jni/Types.h
@@ -0,0 +1,123 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_jni_Types_h__
+#define mozilla_jni_Types_h__
+
+#include <jni.h>
+
+#include "mozilla/jni/Refs.h"
+#include "mozilla/jni/TypeAdapter.h"
+
+namespace mozilla {
+namespace jni {
+namespace detail {
+
+// TypeAdapter specializations are the interfaces between native/C++ types such
+// as int32_t and JNI types such as jint. The template parameter T is the native
+// type, and each TypeAdapter specialization can have the following members:
+//
+//  * Call: JNIEnv member pointer for making a method call that returns T.
+//  * StaticCall: JNIEnv member pointer for making a static call that returns T.
+//  * Get: JNIEnv member pointer for getting a field of type T.
+//  * StaticGet: JNIEnv member pointer for getting a static field of type T.
+//  * Set: JNIEnv member pointer for setting a field of type T.
+//  * StaticGet: JNIEnv member pointer for setting a static field of type T.
+//  * ToNative: static function that converts the JNI type to the native type.
+//  * FromNative: static function that converts the native type to the JNI type.
+
+// TypeAdapter<LocalRef<Cls>> applies when jobject is a return value.
+template <class Cls>
+struct TypeAdapter<LocalRef<Cls>> {
+  using JNIType = typename Cls::Ref::JNIType;
+
+  static constexpr auto Call = &JNIEnv::CallObjectMethodA;
+  static constexpr auto StaticCall = &JNIEnv::CallStaticObjectMethodA;
+  static constexpr auto Get = &JNIEnv::GetObjectField;
+  static constexpr auto StaticGet = &JNIEnv::GetStaticObjectField;
+
+  // Declare instance as jobject because JNI methods return
+  // jobject even if the return value is really jstring, etc.
+  static LocalRef<Cls> ToNative(JNIEnv* env, jobject instance) {
+    return LocalRef<Cls>::Adopt(env, JNIType(instance));
+  }
+
+  static JNIType FromNative(JNIEnv*, LocalRef<Cls>&& instance) {
+    return instance.Forget();
+  }
+};
+
+// clang is picky about function types, including attributes that modify the
+// calling convention, lining up.  GCC appears to be somewhat less so.
+#ifdef __clang__
+#  define MOZ_JNICALL_ABI JNICALL
+#else
+#  define MOZ_JNICALL_ABI
+#endif
+
+// NDK r18 made jvalue* method parameters const. We detect the change directly
+// instead of using ndk-version.h in order to remain compatible with r15 for
+// now, which doesn't include those headers.
+class CallArgs {
+  static const jvalue* test(void (JNIEnv::*)(jobject, jmethodID,
+                                             const jvalue*));
+  static jvalue* test(void (JNIEnv::*)(jobject, jmethodID, jvalue*));
+
+ public:
+  using JValueType = decltype(test(&JNIEnv::CallVoidMethodA));
+};
+
+template <class Cls>
+constexpr jobject (JNIEnv::*TypeAdapter<LocalRef<Cls>>::Call)(
+    jobject, jmethodID, CallArgs::JValueType) MOZ_JNICALL_ABI;
+template <class Cls>
+constexpr jobject (JNIEnv::*TypeAdapter<LocalRef<Cls>>::StaticCall)(
+    jclass, jmethodID, CallArgs::JValueType) MOZ_JNICALL_ABI;
+template <class Cls>
+constexpr jobject (JNIEnv::*TypeAdapter<LocalRef<Cls>>::Get)(jobject, jfieldID);
+template <class Cls>
+constexpr jobject (JNIEnv::*TypeAdapter<LocalRef<Cls>>::StaticGet)(jclass,
+                                                                   jfieldID);
+
+// TypeAdapter<Ref<Cls>> applies when jobject is a parameter value.
+template <class Cls, typename T>
+struct TypeAdapter<Ref<Cls, T>> {
+  using JNIType = typename Ref<Cls, T>::JNIType;
+
+  static constexpr auto Set = &JNIEnv::SetObjectField;
+  static constexpr auto StaticSet = &JNIEnv::SetStaticObjectField;
+
+  static DependentRef<Cls> ToNative(JNIEnv* env, JNIType instance) {
+    return DependentRef<Cls>(instance);
+  }
+
+  static JNIType FromNative(JNIEnv*, const Ref<Cls, T>& instance) {
+    return instance.Get();
+  }
+};
+
+template <class Cls, typename T>
+constexpr void (JNIEnv::*TypeAdapter<Ref<Cls, T>>::Set)(jobject, jfieldID,
+                                                        jobject);
+template <class Cls, typename T>
+constexpr void (JNIEnv::*TypeAdapter<Ref<Cls, T>>::StaticSet)(jclass, jfieldID,
+                                                              jobject);
+
+// jstring has its own Param type.
+template <>
+struct TypeAdapter<StringParam> : public TypeAdapter<String::Ref> {};
+
+template <class Cls>
+struct TypeAdapter<const Cls&> : public TypeAdapter<Cls> {};
+
+}  // namespace detail
+
+using namespace detail;
+
+}  // namespace jni
+}  // namespace mozilla
+
+#endif  // mozilla_jni_Types_h__
diff --git a/widget/android/jni/Utils.cpp b/widget/android/jni/Utils.cpp
new file mode 100644
index 0000000000..08164e4950
--- /dev/null
+++ b/widget/android/jni/Utils.cpp
@@ -0,0 +1,348 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Utils.h"
+#include "Types.h"
+
+#include <android/log.h>
+#include <pthread.h>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/java/GeckoAppShellWrappers.h"
+#include "mozilla/java/GeckoThreadWrappers.h"
+
+#include "AndroidBuild.h"
+#include "nsAppShell.h"
+#include "nsExceptionHandler.h"
+
+namespace mozilla {
+namespace jni {
+
+namespace detail {
+
+#define DEFINE_PRIMITIVE_TYPE_ADAPTER(NativeType, JNIType, JNIName, ABIName)   \
+                                                                               \
+  constexpr JNIType (JNIEnv::*TypeAdapter<NativeType>::Call)(                  \
+      jobject, jmethodID, CallArgs::JValueType) MOZ_JNICALL_ABI;               \
+  constexpr JNIType (JNIEnv::*TypeAdapter<NativeType>::StaticCall)(            \
+      jclass, jmethodID, CallArgs::JValueType) MOZ_JNICALL_ABI;                \
+  constexpr JNIType (JNIEnv::*TypeAdapter<NativeType>::Get)(jobject, jfieldID) \
+      ABIName;                                                                 \
+  constexpr JNIType (JNIEnv::*TypeAdapter<NativeType>::StaticGet)(             \
+      jclass, jfieldID) ABIName;                                               \
+  constexpr void (JNIEnv::*TypeAdapter<NativeType>::Set)(jobject, jfieldID,    \
+                                                         JNIType) ABIName;     \
+  constexpr void (JNIEnv::*TypeAdapter<NativeType>::StaticSet)(                \
+      jclass, jfieldID, JNIType) ABIName;                                      \
+  constexpr void (JNIEnv::*TypeAdapter<NativeType>::GetArray)(                 \
+      JNIType##Array, jsize, jsize, JNIType*)
+
+DEFINE_PRIMITIVE_TYPE_ADAPTER(bool, jboolean, Boolean, /*nothing*/);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(int8_t, jbyte, Byte, /*nothing*/);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(char16_t, jchar, Char, /*nothing*/);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(int16_t, jshort, Short, /*nothing*/);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(int32_t, jint, Int, /*nothing*/);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(int64_t, jlong, Long, /*nothing*/);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(float, jfloat, Float, MOZ_JNICALL_ABI);
+DEFINE_PRIMITIVE_TYPE_ADAPTER(double, jdouble, Double, MOZ_JNICALL_ABI);
+
+#undef DEFINE_PRIMITIVE_TYPE_ADAPTER
+
+}  // namespace detail
+
+template <>
+const char ObjectBase<Object, jobject>::name[] = "java/lang/Object";
+template <>
+const char ObjectBase<TypedObject<jstring>, jstring>::name[] =
+    "java/lang/String";
+template <>
+const char ObjectBase<TypedObject<jclass>, jclass>::name[] = "java/lang/Class";
+template <>
+const char ObjectBase<TypedObject<jthrowable>, jthrowable>::name[] =
+    "java/lang/Throwable";
+template <>
+const char ObjectBase<BoxedObject<jboolean>, jobject>::name[] =
+    "java/lang/Boolean";
+template <>
+const char ObjectBase<BoxedObject<jbyte>, jobject>::name[] = "java/lang/Byte";
+template <>
+const char ObjectBase<BoxedObject<jchar>, jobject>::name[] =
+    "java/lang/Character";
+template <>
+const char ObjectBase<BoxedObject<jshort>, jobject>::name[] = "java/lang/Short";
+template <>
+const char ObjectBase<BoxedObject<jint>, jobject>::name[] = "java/lang/Integer";
+template <>
+const char ObjectBase<BoxedObject<jlong>, jobject>::name[] = "java/lang/Long";
+template <>
+const char ObjectBase<BoxedObject<jfloat>, jobject>::name[] = "java/lang/Float";
+template <>
+const char ObjectBase<BoxedObject<jdouble>, jobject>::name[] =
+    "java/lang/Double";
+template <>
+const char ObjectBase<TypedObject<jbooleanArray>, jbooleanArray>::name[] = "[Z";
+template <>
+const char ObjectBase<TypedObject<jbyteArray>, jbyteArray>::name[] = "[B";
+template <>
+const char ObjectBase<TypedObject<jcharArray>, jcharArray>::name[] = "[C";
+template <>
+const char ObjectBase<TypedObject<jshortArray>, jshortArray>::name[] = "[S";
+template <>
+const char ObjectBase<TypedObject<jintArray>, jintArray>::name[] = "[I";
+template <>
+const char ObjectBase<TypedObject<jlongArray>, jlongArray>::name[] = "[J";
+template <>
+const char ObjectBase<TypedObject<jfloatArray>, jfloatArray>::name[] = "[F";
+template <>
+const char ObjectBase<TypedObject<jdoubleArray>, jdoubleArray>::name[] = "[D";
+template <>
+const char ObjectBase<TypedObject<jobjectArray>, jobjectArray>::name[] =
+    "[Ljava/lang/Object;";
+template <>
+const char ObjectBase<ByteBuffer, jobject>::name[] = "java/nio/ByteBuffer";
+
+JavaVM* sJavaVM;
+JNIEnv* sGeckoThreadEnv;
+
+namespace {
+
+pthread_key_t sThreadEnvKey;
+jclass sOOMErrorClass;
+jobject sClassLoader;
+jmethodID sClassLoaderLoadClass;
+
+void UnregisterThreadEnv(void* env) {
+  if (!env) {
+    // We were never attached.
+    return;
+  }
+  // The thread may have already been detached. In that case, it's still
+  // okay to call DetachCurrentThread(); it'll simply return an error.
+  // However, we must not access | env | because it may be invalid.
+  MOZ_ASSERT(sJavaVM);
+  sJavaVM->DetachCurrentThread();
+}
+
+}  // namespace
+
+void SetGeckoThreadEnv(JNIEnv* aEnv) {
+  MOZ_ASSERT(aEnv);
+  MOZ_ASSERT(!sGeckoThreadEnv || sGeckoThreadEnv == aEnv);
+
+  if (!sGeckoThreadEnv &&
+      pthread_key_create(&sThreadEnvKey, UnregisterThreadEnv)) {
+    MOZ_CRASH("Failed to initialize required TLS");
+  }
+
+  sGeckoThreadEnv = aEnv;
+  MOZ_ALWAYS_TRUE(!pthread_setspecific(sThreadEnvKey, aEnv));
+
+  MOZ_ALWAYS_TRUE(!aEnv->GetJavaVM(&sJavaVM));
+  MOZ_ASSERT(sJavaVM);
+
+  sOOMErrorClass =
+      Class::GlobalRef(
+          Class::LocalRef::Adopt(aEnv->FindClass("java/lang/OutOfMemoryError")))
+          .Forget();
+  aEnv->ExceptionClear();
+
+  sClassLoader = Object::GlobalRef(java::GeckoThread::ClsLoader()).Forget();
+  sClassLoaderLoadClass = aEnv->GetMethodID(
+      Class::LocalRef::Adopt(aEnv->GetObjectClass(sClassLoader)).Get(),
+      "loadClass", "(Ljava/lang/String;)Ljava/lang/Class;");
+  MOZ_ASSERT(sClassLoader && sClassLoaderLoadClass);
+}
+
+JNIEnv* GetEnvForThread() {
+  MOZ_ASSERT(sGeckoThreadEnv);
+
+  JNIEnv* env = static_cast<JNIEnv*>(pthread_getspecific(sThreadEnvKey));
+  if (env) {
+    return env;
+  }
+
+  // We don't have a saved JNIEnv, so try to get one.
+  // AttachCurrentThread() does the same thing as GetEnv() when a thread is
+  // already attached, so we don't have to call GetEnv() at all.
+  if (!sJavaVM->AttachCurrentThread(&env, nullptr)) {
+    MOZ_ASSERT(env);
+    MOZ_ALWAYS_TRUE(!pthread_setspecific(sThreadEnvKey, env));
+    return env;
+  }
+
+  MOZ_CRASH("Failed to get JNIEnv for thread");
+  return nullptr;  // unreachable
+}
+
+bool ThrowException(JNIEnv* aEnv, const char* aClass, const char* aMessage) {
+  MOZ_ASSERT(aEnv, "Invalid thread JNI env");
+
+  Class::LocalRef cls = Class::LocalRef::Adopt(aEnv->FindClass(aClass));
+  MOZ_ASSERT(cls, "Cannot find exception class");
+
+  return !aEnv->ThrowNew(cls.Get(), aMessage);
+}
+
+bool HandleUncaughtException(JNIEnv* aEnv) {
+  MOZ_ASSERT(aEnv, "Invalid thread JNI env");
+
+  if (!aEnv->ExceptionCheck()) {
+    return false;
+  }
+
+#ifdef MOZ_CHECK_JNI
+  aEnv->ExceptionDescribe();
+#endif
+
+  Throwable::LocalRef e =
+      Throwable::LocalRef::Adopt(aEnv, aEnv->ExceptionOccurred());
+  MOZ_ASSERT(e);
+  aEnv->ExceptionClear();
+
+  String::LocalRef stack = java::GeckoAppShell::GetExceptionStackTrace(e);
+  if (stack && ReportException(aEnv, e.Get(), stack.Get())) {
+    return true;
+  }
+
+  aEnv->ExceptionClear();
+  java::GeckoAppShell::HandleUncaughtException(e);
+
+  if (NS_WARN_IF(aEnv->ExceptionCheck())) {
+    aEnv->ExceptionDescribe();
+    aEnv->ExceptionClear();
+  }
+
+  return true;
+}
+
+bool ReportException(JNIEnv* aEnv, jthrowable aExc, jstring aStack) {
+  bool result = true;
+
+  result &= NS_SUCCEEDED(CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::JavaStackTrace,
+      String::Ref::From(aStack)->ToCString()));
+
+  auto appNotes = java::GeckoAppShell::GetAppNotes();
+  if (NS_WARN_IF(aEnv->ExceptionCheck())) {
+    aEnv->ExceptionDescribe();
+    aEnv->ExceptionClear();
+  } else if (appNotes) {
+    CrashReporter::AppendAppNotesToCrashReport("\n"_ns + appNotes->ToCString());
+  }
+
+  if (sOOMErrorClass && aEnv->IsInstanceOf(aExc, sOOMErrorClass)) {
+    NS_ABORT_OOM(0);  // Unknown OOM size
+  }
+  return result;
+}
+
+namespace {
+
+jclass sJNIObjectClass;
+jfieldID sJNIObjectHandleField;
+
+bool EnsureJNIObject(JNIEnv* env, jobject instance) {
+  if (!sJNIObjectClass) {
+    sJNIObjectClass =
+        Class::GlobalRef(Class::LocalRef::Adopt(GetClassRef(
+                             env, "org/mozilla/gecko/mozglue/JNIObject")))
+            .Forget();
+
+    sJNIObjectHandleField = env->GetFieldID(sJNIObjectClass, "mHandle", "J");
+  }
+
+  MOZ_ASSERT(env->IsInstanceOf(instance, sJNIObjectClass),
+             "Java class is not derived from JNIObject");
+  return true;
+}
+
+}  // namespace
+
+uintptr_t GetNativeHandle(JNIEnv* env, jobject instance) {
+  if (!EnsureJNIObject(env, instance)) {
+    return 0;
+  }
+
+  return static_cast<uintptr_t>(
+      env->GetLongField(instance, sJNIObjectHandleField));
+}
+
+void SetNativeHandle(JNIEnv* env, jobject instance, uintptr_t handle) {
+  if (!EnsureJNIObject(env, instance)) {
+    return;
+  }
+
+  env->SetLongField(instance, sJNIObjectHandleField,
+                    static_cast<jlong>(handle));
+}
+
+jclass GetClassRef(JNIEnv* aEnv, const char* aClassName) {
+  // First try the default class loader.
+  auto classRef = Class::LocalRef::Adopt(aEnv, aEnv->FindClass(aClassName));
+
+  if ((!classRef || aEnv->ExceptionCheck()) && sClassLoader) {
+    // If the default class loader failed but we have an app class loader, try
+    // that. Clear the pending exception from failed FindClass call above.
+    aEnv->ExceptionClear();
+    classRef = Class::LocalRef::Adopt(
+        aEnv,
+        jclass(aEnv->CallObjectMethod(sClassLoader, sClassLoaderLoadClass,
+                                      StringParam(aClassName, aEnv).Get())));
+  }
+
+  if (classRef && !aEnv->ExceptionCheck()) {
+    return classRef.Forget();
+  }
+
+  __android_log_print(
+      ANDROID_LOG_ERROR, "Gecko",
+      ">>> FATAL JNI ERROR! FindClass(\"%s\") failed. "
+      "Does the class require a newer API version? "
+      "Or did ProGuard optimize away something it shouldn't have?",
+      aClassName);
+  aEnv->ExceptionDescribe();
+  MOZ_CRASH("Cannot find JNI class");
+  return nullptr;
+}
+
+void DispatchToGeckoPriorityQueue(already_AddRefed<nsIRunnable> aCall) {
+  class RunnableEvent : public nsAppShell::Event {
+    nsCOMPtr<nsIRunnable> mCall;
+
+   public:
+    explicit RunnableEvent(already_AddRefed<nsIRunnable> aCall)
+        : mCall(aCall) {}
+    void Run() override { NS_ENSURE_SUCCESS_VOID(mCall->Run()); }
+  };
+
+  nsAppShell::PostEvent(MakeUnique<RunnableEvent>(std::move(aCall)));
+}
+
+int GetAPIVersion() {
+  static int32_t apiVersion = 0;
+  if (!apiVersion && IsAvailable()) {
+    apiVersion = java::sdk::Build::VERSION::SDK_INT();
+  }
+  return apiVersion;
+}
+
+pid_t GetUIThreadId() {
+  static pid_t uiThreadId;
+  if (!uiThreadId) {
+    uiThreadId = pid_t(java::GeckoThread::UiThreadId());
+  }
+  return uiThreadId;
+}
+
+bool IsOOMException(JNIEnv* aEnv) {
+  MOZ_ASSERT(aEnv->ExceptionCheck());
+  Throwable::LocalRef e =
+      Throwable::LocalRef::Adopt(aEnv, aEnv->ExceptionOccurred());
+  return sOOMErrorClass && aEnv->IsInstanceOf(e.Get(), sOOMErrorClass);
+}
+
+}  // namespace jni
+}  // namespace mozilla
diff --git a/widget/android/jni/Utils.h b/widget/android/jni/Utils.h
new file mode 100644
index 0000000000..adcafeb44e
--- /dev/null
+++ b/widget/android/jni/Utils.h
@@ -0,0 +1,150 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_jni_Utils_h__
+#define mozilla_jni_Utils_h__
+
+#include <jni.h>
+
+#include "nsIRunnable.h"
+
+#include "mozilla/UniquePtr.h"
+
+#if defined(DEBUG) || !defined(RELEASE_OR_BETA)
+#  define MOZ_CHECK_JNI
+#endif
+
+#ifdef MOZ_CHECK_JNI
+#  include <unistd.h>
+#  include "mozilla/Assertions.h"
+#  include "APKOpen.h"
+#  include "MainThreadUtils.h"
+#endif
+
+namespace mozilla {
+namespace jni {
+
+// How exception during a JNI call should be treated.
+enum class ExceptionMode {
+  // Abort on unhandled excepion (default).
+  ABORT,
+  // Ignore the exception and return to caller.
+  IGNORE,
+  // Catch any exception and return a nsresult.
+  NSRESULT,
+};
+
+// Thread that a particular JNI call is allowed on.
+enum class CallingThread {
+  // Can be called from any thread (default).
+  ANY,
+  // Can be called from the Gecko thread.
+  GECKO,
+  // Can be called from the Java UI thread.
+  UI,
+};
+
+// If and where a JNI call will be dispatched.
+enum class DispatchTarget {
+  // Call happens synchronously on the calling thread (default).
+  CURRENT,
+  // Call happens synchronously on the calling thread, but the call is
+  // wrapped in a function object and is passed thru UsesNativeCallProxy.
+  // Method must return void.
+  PROXY,
+  // Call is dispatched asynchronously on the Gecko thread to the XPCOM
+  // (nsThread) event queue. Method must return void.
+  GECKO,
+  // Call is dispatched asynchronously on the Gecko thread to the widget
+  // (nsAppShell) event queue. In most cases, events in the widget event
+  // queue (aka native event queue) are favored over events in the XPCOM
+  // event queue. Method must return void.
+  GECKO_PRIORITY,
+};
+
+extern JavaVM* sJavaVM;
+extern JNIEnv* sGeckoThreadEnv;
+
+inline bool IsAvailable() { return !!sGeckoThreadEnv; }
+
+inline JavaVM* GetVM() {
+#ifdef MOZ_CHECK_JNI
+  MOZ_ASSERT(sJavaVM);
+#endif
+  return sJavaVM;
+}
+
+inline JNIEnv* GetGeckoThreadEnv() {
+#ifdef MOZ_CHECK_JNI
+  MOZ_RELEASE_ASSERT(NS_IsMainThread(), "Must be on Gecko thread");
+  MOZ_RELEASE_ASSERT(sGeckoThreadEnv, "Must have a JNIEnv");
+#endif
+  return sGeckoThreadEnv;
+}
+
+void SetGeckoThreadEnv(JNIEnv* aEnv);
+
+JNIEnv* GetEnvForThread();
+
+#ifdef MOZ_CHECK_JNI
+#  define MOZ_ASSERT_JNI_THREAD(thread)                            \
+    do {                                                           \
+      if ((thread) == mozilla::jni::CallingThread::GECKO) {        \
+        MOZ_RELEASE_ASSERT(::NS_IsMainThread());                   \
+      } else if ((thread) == mozilla::jni::CallingThread::UI) {    \
+        const bool isOnUiThread = (GetUIThreadId() == ::gettid()); \
+        MOZ_RELEASE_ASSERT(isOnUiThread);                          \
+      }                                                            \
+    } while (0)
+#else
+#  define MOZ_ASSERT_JNI_THREAD(thread) \
+    do {                                \
+    } while (0)
+#endif
+
+bool ThrowException(JNIEnv* aEnv, const char* aClass, const char* aMessage);
+
+inline bool ThrowException(JNIEnv* aEnv, const char* aMessage) {
+  return ThrowException(aEnv, "java/lang/Exception", aMessage);
+}
+
+inline bool ThrowException(const char* aClass, const char* aMessage) {
+  return ThrowException(GetEnvForThread(), aClass, aMessage);
+}
+
+inline bool ThrowException(const char* aMessage) {
+  return ThrowException(GetEnvForThread(), aMessage);
+}
+
+bool HandleUncaughtException(JNIEnv* aEnv);
+
+bool ReportException(JNIEnv* aEnv, jthrowable aExc, jstring aStack);
+
+#define MOZ_CATCH_JNI_EXCEPTION(env)                    \
+  do {                                                  \
+    if (mozilla::jni::HandleUncaughtException((env))) { \
+      MOZ_CRASH("JNI exception");                       \
+    }                                                   \
+  } while (0)
+
+uintptr_t GetNativeHandle(JNIEnv* env, jobject instance);
+
+void SetNativeHandle(JNIEnv* env, jobject instance, uintptr_t handle);
+
+jclass GetClassRef(JNIEnv* aEnv, const char* aClassName);
+
+void DispatchToGeckoPriorityQueue(already_AddRefed<nsIRunnable> aCall);
+
+int GetAPIVersion();
+
+pid_t GetUIThreadId();
+
+bool IsOOMException(JNIEnv* aEnv);
+
+}  // namespace jni
+}  // namespace mozilla
+
+#endif  // mozilla_jni_Utils_h__
diff --git a/widget/android/jni/moz.build b/widget/android/jni/moz.build
new file mode 100644
index 0000000000..53bef6663f
--- /dev/null
+++ b/widget/android/jni/moz.build
@@ -0,0 +1,36 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("GeckoView", "General")
+
+EXPORTS.mozilla.jni += [
+    "Accessors.h",
+    "Conversions.h",
+    "GeckoBundleUtils.h",
+    "GeckoResultUtils.h",
+    "Natives.h",
+    "NativesInlines.h",
+    "Refs.h",
+    "TypeAdapter.h",
+    "Types.h",
+    "Utils.h",
+]
+
+UNIFIED_SOURCES += [
+    "Conversions.cpp",
+    "GeckoBundleUtils.cpp",
+    "Utils.cpp",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
+
+LOCAL_INCLUDES += [
+    "/widget",
+    "/widget/android",
+]
diff --git a/widget/android/moz.build b/widget/android/moz.build
new file mode 100644
index 0000000000..e4525bb747
--- /dev/null
+++ b/widget/android/moz.build
@@ -0,0 +1,207 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("GeckoView", "General")
+    SCHEDULES.exclusive = ["android"]
+
+with Files("*CompositorWidget*"):
+    BUG_COMPONENT = ("Core", "Graphics")
+
+DIRS += [
+    "bindings",
+    "jni",
+]
+
+XPIDL_SOURCES += [
+    "nsIAndroidBridge.idl",
+]
+
+XPIDL_MODULE = "widget_android"
+
+EXPORTS += [
+    "AndroidBridge.h",
+]
+
+classes_with_WrapForJNI = [
+    "AndroidGamepadManager",
+    "AndroidVsync",
+    "Base64Utils",
+    "Clipboard",
+    "CodecProxy",
+    "CompositorSurfaceManager",
+    "ContentInputStream",
+    "EnterpriseRoots",
+    "EventCallback",
+    "EventDispatcher",
+    "GeckoAppShell",
+    "GeckoAudioInfo",
+    "GeckoBatteryManager",
+    "GeckoBundle",
+    "GeckoDragAndDrop",
+    "GeckoEditableChild",
+    "GeckoHLSDemuxerWrapper",
+    "GeckoHLSResourceWrapper",
+    "GeckoHLSSample",
+    "GeckoInputStream",
+    "GeckoJavaSampler",
+    "GeckoNetworkManager",
+    "GeckoProcessManager",
+    "GeckoProcessType",
+    "GeckoResult",
+    "GeckoRuntime",
+    "GeckoServiceChildProcess",
+    "GeckoServiceGpuProcess",
+    "GeckoSession",
+    "GeckoSurface",
+    "GeckoSurfaceTexture",
+    "GeckoSystemStateListener",
+    "GeckoThread",
+    "GeckoViewInputStream",
+    "GeckoVRManager",
+    "GeckoVideoInfo",
+    "GeckoWebExecutor",
+    "HardwareCodecCapabilityUtils",
+    "Image",
+    "ImageDecoder",
+    "MediaDrmProxy",
+    "PanZoomController",
+    "RuntimeTelemetry",
+    "Sample",
+    "SampleBuffer",
+    "ScreenManagerHelper",
+    "ServiceAllocator",
+    "SessionAccessibility",
+    "SessionKeyInfo",
+    "SessionTextInput",
+    "SpeechSynthesisService",
+    "SurfaceAllocator",
+    "SurfaceControlManager",
+    "SurfaceTextureListener",
+    "TelemetryUtils",
+    "WebAuthnTokenManager",
+    "WebMessage",
+    "WebNotification",
+    "WebNotificationDelegate",
+    "WebRequest",
+    "WebRequestError",
+    "WebResponse",
+    "XPCOMEventTarget",
+]
+
+natives_from_WrapForJNI = sorted(
+    ["GeneratedJNI/{}Natives.h".format(c) for c in classes_with_WrapForJNI]
+)
+
+wrappers_from_WrapForJNI = sorted(
+    ["GeneratedJNI/{}Wrappers.h".format(c) for c in classes_with_WrapForJNI]
+)
+
+sources_from_WrapForJNI = sorted(
+    "GeneratedJNI{}Wrappers.cpp".format(c) for c in classes_with_WrapForJNI
+)
+
+EXPORTS.mozilla.widget += [
+    "AndroidCompositorWidget.h",
+    "AndroidUiThread.h",
+    "AndroidView.h",
+    "AndroidVsync.h",
+    "AndroidWidgetUtils.h",
+    "CompositorWidgetChild.h",
+    "CompositorWidgetParent.h",
+    "EventDispatcher.h",
+    "GeckoViewSupport.h",
+    "InProcessAndroidCompositorWidget.h",
+    "nsWindow.h",
+    "WindowEvent.h",
+]
+
+EXPORTS.mozilla.java += ["!{}".format(c) for c in natives_from_WrapForJNI]
+
+EXPORTS.mozilla.java += ["!{}".format(c) for c in wrappers_from_WrapForJNI]
+
+SOURCES += ["!{}".format(c) for c in sources_from_WrapForJNI]
+
+SOURCES += [
+    "MediaKeysEventSourceFactory.cpp",
+]
+
+UNIFIED_SOURCES += [
+    "AndroidAlerts.cpp",
+    "AndroidBridge.cpp",
+    "AndroidCompositorWidget.cpp",
+    "AndroidContentController.cpp",
+    "AndroidUiThread.cpp",
+    "AndroidVsync.cpp",
+    "AndroidWidgetUtils.cpp",
+    "CompositorWidgetChild.cpp",
+    "CompositorWidgetParent.cpp",
+    "EventDispatcher.cpp",
+    "GeckoEditableSupport.cpp",
+    "GeckoProcessManager.cpp",
+    "GfxInfo.cpp",
+    "ImageDecoderSupport.cpp",
+    "InProcessAndroidCompositorWidget.cpp",
+    "nsAppShell.cpp",
+    "nsClipboard.cpp",
+    "nsDeviceContextAndroid.cpp",
+    "nsDragService.cpp",
+    "nsLookAndFeel.cpp",
+    "nsPrintSettingsServiceAndroid.cpp",
+    "nsUserIdleServiceAndroid.cpp",
+    "nsWidgetFactory.cpp",
+    "nsWindow.cpp",
+    "ScreenHelperAndroid.cpp",
+    "WebExecutorSupport.cpp",
+]
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+# The recursive make backend treats the first output specially: it's passed as
+# an open FileAvoidWrite to the invoked script.  That doesn't work well with
+# the Gradle task that generates all of the outputs, so we add a dummy first
+# output.
+
+t = tuple(
+    ["generated_jni_wrappers"]
+    + natives_from_WrapForJNI
+    + sources_from_WrapForJNI
+    + wrappers_from_WrapForJNI
+)
+
+GeneratedFile(
+    *t,
+    script="/mobile/android/gradle.py",
+    entry_point="generate_generated_jni_wrappers"
+)
+
+FINAL_LIBRARY = "xul"
+
+LOCAL_INCLUDES += [
+    "/docshell/base",
+    "/dom/base",
+    "/dom/system/android",
+    "/gfx/2d",
+    "/gfx/vr",
+    "/layout/forms",
+    "/layout/painting",
+    "/netwerk/base",
+    "/toolkit/components/telemetry",
+    "/widget",
+    "/widget/headless",
+    "/xpcom/threads",
+]
+
+OS_LIBS += ["android"]
+
+if CONFIG["MOZ_NATIVE_DEVICES"]:
+    DEFINES["MOZ_NATIVE_DEVICES"] = True
+
+# DEFINES['DEBUG_WIDGETS'] = True
diff --git a/widget/android/nsAppShell.cpp b/widget/android/nsAppShell.cpp
new file mode 100644
index 0000000000..4d396945c4
--- /dev/null
+++ b/widget/android/nsAppShell.cpp
@@ -0,0 +1,755 @@
+/* -*- Mode: c++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsAppShell.h"
+
+#include "base/basictypes.h"
+#include "base/message_loop.h"
+#include "base/task.h"
+#include "mozilla/Hal.h"
+#include "gfxConfig.h"
+#include "nsDragService.h"
+#include "nsExceptionHandler.h"
+#include "nsIScreen.h"
+#include "nsWindow.h"
+#include "nsThreadUtils.h"
+#include "nsIObserverService.h"
+#include "nsIAppStartup.h"
+#include "nsIGeolocationProvider.h"
+#include "nsIDOMWakeLockListener.h"
+#include "nsIPowerManagerService.h"
+#include "nsISpeculativeConnect.h"
+#include "nsIURIFixup.h"
+#include "nsCategoryManagerUtils.h"
+#include "mozilla/dom/GeolocationPosition.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/AppShutdown.h"
+#include "mozilla/Components.h"
+#include "mozilla/Services.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/Hal.h"
+#include "mozilla/dom/BrowserChild.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/intl/OSPreferences.h"
+#include "mozilla/ipc/GeckoChildProcessHost.h"
+#include "mozilla/java/GeckoAppShellNatives.h"
+#include "mozilla/java/GeckoDragAndDropNatives.h"
+#include "mozilla/java/GeckoResultWrappers.h"
+#include "mozilla/java/GeckoThreadNatives.h"
+#include "mozilla/java/XPCOMEventTargetNatives.h"
+#include "mozilla/widget/ScreenManager.h"
+#include "prenv.h"
+#include "prtime.h"
+
+#include "AndroidBridge.h"
+#include "AndroidBridgeUtilities.h"
+#include "AndroidSurfaceTexture.h"
+#include <android/log.h>
+#include <pthread.h>
+#include <wchar.h>
+
+#ifdef MOZ_ANDROID_HISTORY
+#  include "nsNetUtil.h"
+#  include "nsIURI.h"
+#  include "IHistory.h"
+#endif
+
+#ifdef MOZ_LOGGING
+#  include "mozilla/Logging.h"
+#endif
+
+#include "AndroidAlerts.h"
+#include "AndroidUiThread.h"
+#include "GeckoBatteryManager.h"
+#include "GeckoEditableSupport.h"
+#include "GeckoNetworkManager.h"
+#include "GeckoProcessManager.h"
+#include "GeckoSystemStateListener.h"
+#include "GeckoTelemetryDelegate.h"
+#include "GeckoVRManager.h"
+#include "ImageDecoderSupport.h"
+#include "JavaBuiltins.h"
+#include "ScreenHelperAndroid.h"
+#include "Telemetry.h"
+#include "WebExecutorSupport.h"
+#include "Base64UtilsSupport.h"
+
+#ifdef DEBUG_ANDROID_EVENTS
+#  define EVLOG(args...) ALOG(args)
+#else
+#  define EVLOG(args...) \
+    do {                 \
+    } while (0)
+#endif
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+nsIGeolocationUpdate* gLocationCallback = nullptr;
+
+nsAppShell* nsAppShell::sAppShell;
+StaticAutoPtr<Mutex> nsAppShell::sAppShellLock;
+
+NS_IMPL_ISUPPORTS_INHERITED(nsAppShell, nsBaseAppShell, nsIObserver)
+
+class WakeLockListener final : public nsIDOMMozWakeLockListener {
+ private:
+  ~WakeLockListener() {}
+
+ public:
+  NS_DECL_ISUPPORTS;
+
+  nsresult Callback(const nsAString& topic, const nsAString& state) override {
+    java::GeckoAppShell::NotifyWakeLockChanged(topic, state);
+    return NS_OK;
+  }
+};
+
+NS_IMPL_ISUPPORTS(WakeLockListener, nsIDOMMozWakeLockListener)
+nsCOMPtr<nsIPowerManagerService> sPowerManagerService = nullptr;
+StaticRefPtr<WakeLockListener> sWakeLockListener;
+
+class GeckoThreadSupport final
+    : public java::GeckoThread::Natives<GeckoThreadSupport> {
+  // When this number goes above 0, the app is paused. When less than or
+  // equal to zero, the app is resumed.
+  static int32_t sPauseCount;
+
+ public:
+  static void SpeculativeConnect(jni::String::Param aUriStr) {
+    if (!NS_IsMainThread()) {
+      // We will be on the main thread if the call was queued on the Java
+      // side during startup. Otherwise, the call was not queued, which
+      // means Gecko is already sufficiently loaded, and we don't really
+      // care about speculative connections at this point.
+      return;
+    }
+
+    nsCOMPtr<nsIIOService> ioServ = do_GetIOService();
+    nsCOMPtr<nsISpeculativeConnect> specConn = do_QueryInterface(ioServ);
+    if (!specConn) {
+      return;
+    }
+
+    nsCOMPtr<nsIURI> uri = nsAppShell::ResolveURI(aUriStr->ToCString());
+    if (!uri) {
+      return;
+    }
+
+    OriginAttributes attrs;
+    nsCOMPtr<nsIPrincipal> principal =
+        BasePrincipal::CreateContentPrincipal(uri, attrs);
+    specConn->SpeculativeConnect(uri, principal, nullptr, false);
+  }
+
+  static void OnPause() {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    sPauseCount++;
+    // If sPauseCount is now 1, we just crossed the threshold from "resumed"
+    // "paused". so we should notify observers and so on.
+    if (sPauseCount != 1) {
+      return;
+    }
+
+    nsCOMPtr<nsIObserverService> obsServ =
+        mozilla::services::GetObserverService();
+    obsServ->NotifyObservers(nullptr, "application-background", nullptr);
+
+    obsServ->NotifyObservers(nullptr, "memory-pressure", u"heap-minimize");
+
+    // We really want to send a notification like profile-before-change,
+    // but profile-before-change ends up shutting some things down instead
+    // of flushing data
+    Preferences* prefs = static_cast<Preferences*>(Preferences::GetService());
+    if (prefs) {
+      // Force a main thread blocking save
+      prefs->SavePrefFileBlocking();
+    }
+  }
+
+  static void OnResume() {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    sPauseCount--;
+    // If sPauseCount is now 0, we just crossed the threshold from "paused"
+    // to "resumed", so we should notify observers and so on.
+    if (sPauseCount != 0) {
+      return;
+    }
+
+    // We didn't return from one of our own activities, so restore
+    // to foreground status
+    nsCOMPtr<nsIObserverService> obsServ =
+        mozilla::services::GetObserverService();
+    obsServ->NotifyObservers(nullptr, "application-foreground", nullptr);
+  }
+
+  static void CreateServices(jni::String::Param aCategory,
+                             jni::String::Param aData) {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    nsCString category(aCategory->ToCString());
+
+    NS_CreateServicesFromCategory(category.get(),
+                                  nullptr,  // aOrigin
+                                  category.get(),
+                                  aData ? aData->ToString().get() : nullptr);
+  }
+
+  static int64_t RunUiThreadCallback() { return RunAndroidUiTasks(); }
+
+  static void ForceQuit() {
+    nsCOMPtr<nsIAppStartup> appStartup = components::AppStartup::Service();
+
+    if (appStartup) {
+      bool userAllowedQuit = true;
+      appStartup->Quit(nsIAppStartup::eForceQuit, 0, &userAllowedQuit);
+    }
+  }
+
+  static void Crash() {
+    printf_stderr("Intentionally crashing...\n");
+    MOZ_CRASH("intentional crash");
+  }
+};
+
+int32_t GeckoThreadSupport::sPauseCount;
+
+class GeckoAppShellSupport final
+    : public java::GeckoAppShell::Natives<GeckoAppShellSupport> {
+ public:
+  static void ReportJavaCrash(const jni::Class::LocalRef& aCls,
+                              jni::Throwable::Param aException,
+                              jni::String::Param aStack) {
+    if (!jni::ReportException(aCls.Env(), aException.Get(), aStack.Get())) {
+      // Only crash below if crash reporter is initialized and annotation
+      // succeeded. Otherwise try other means of reporting the crash in
+      // Java.
+      return;
+    }
+
+    MOZ_CRASH("Uncaught Java exception");
+  }
+
+  static void NotifyObservers(jni::String::Param aTopic,
+                              jni::String::Param aData) {
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(aTopic);
+
+    nsCOMPtr<nsIObserverService> obsServ = services::GetObserverService();
+    if (!obsServ) {
+      return;
+    }
+
+    obsServ->NotifyObservers(nullptr, aTopic->ToCString().get(),
+                             aData ? aData->ToString().get() : nullptr);
+  }
+
+  static void AppendAppNotesToCrashReport(jni::String::Param aNotes) {
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(aNotes);
+    CrashReporter::AppendAppNotesToCrashReport(aNotes->ToCString());
+  }
+
+  static void OnSensorChanged(int32_t aType, float aX, float aY, float aZ,
+                              float aW, int64_t aTime) {
+    AutoTArray<float, 4> values;
+
+    switch (aType) {
+      // Bug 938035, transfer HAL data for orientation sensor to meet w3c
+      // spec, ex: HAL report alpha=90 means East but alpha=90 means West
+      // in w3c spec
+      case hal::SENSOR_ORIENTATION:
+        values.AppendElement(360.0f - aX);
+        values.AppendElement(-aY);
+        values.AppendElement(-aZ);
+        break;
+
+      case hal::SENSOR_LINEAR_ACCELERATION:
+      case hal::SENSOR_ACCELERATION:
+      case hal::SENSOR_GYROSCOPE:
+        values.AppendElement(aX);
+        values.AppendElement(aY);
+        values.AppendElement(aZ);
+        break;
+
+      case hal::SENSOR_LIGHT:
+        values.AppendElement(aX);
+        break;
+
+      case hal::SENSOR_ROTATION_VECTOR:
+      case hal::SENSOR_GAME_ROTATION_VECTOR:
+        values.AppendElement(aX);
+        values.AppendElement(aY);
+        values.AppendElement(aZ);
+        values.AppendElement(aW);
+        break;
+
+      default:
+        __android_log_print(ANDROID_LOG_ERROR, "Gecko",
+                            "Unknown sensor type %d", aType);
+    }
+
+    hal::SensorData sdata(hal::SensorType(aType), aTime, values);
+    hal::NotifySensorChange(sdata);
+  }
+
+  static void OnLocationChanged(double aLatitude, double aLongitude,
+                                double aAltitude, float aAccuracy,
+                                float aAltitudeAccuracy, float aHeading,
+                                float aSpeed) {
+    if (!gLocationCallback) {
+      return;
+    }
+
+    static constexpr float kEpsilon = 0.0001f;
+    double heading = (aHeading >= kEpsilon && aHeading < (360.0f - kEpsilon) &&
+                      aSpeed > kEpsilon)
+                         ? aHeading
+                         : UnspecifiedNaN<double>();
+
+    RefPtr<nsIDOMGeoPosition> geoPosition(new nsGeoPosition(
+        aLatitude, aLongitude, aAltitude, aAccuracy, aAltitudeAccuracy, heading,
+        aSpeed, PR_Now() / PR_USEC_PER_MSEC));
+    gLocationCallback->Update(geoPosition);
+  }
+
+  static void NotifyAlertListener(jni::String::Param aName,
+                                  jni::String::Param aTopic,
+                                  jni::String::Param aCookie) {
+    if (!aName || !aTopic || !aCookie) {
+      return;
+    }
+
+    widget::AndroidAlerts::NotifyListener(aName->ToString(),
+                                          aTopic->ToCString().get(),
+                                          aCookie->ToString().get());
+  }
+
+  static bool IsParentProcess() { return XRE_IsParentProcess(); }
+
+  static jni::Object::LocalRef IsGpuProcessEnabled() {
+    java::GeckoResult::GlobalRef result = java::GeckoResult::New();
+
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "GeckoAppShellSupport::IsGpuProcessEnabled", [result]() {
+          result->Complete(gfx::gfxConfig::IsEnabled(gfx::Feature::GPU_PROCESS)
+                               ? java::sdk::Boolean::TRUE()
+                               : java::sdk::Boolean::FALSE());
+        }));
+
+    return jni::Object::Ref::From(result);
+  }
+};
+
+class XPCOMEventTargetWrapper final
+    : public java::XPCOMEventTarget::Natives<XPCOMEventTargetWrapper> {
+ public:
+  // Wraps a java runnable into an XPCOM runnable and dispatches it to mTarget.
+  void DispatchNative(mozilla::jni::Object::Param aJavaRunnable) {
+    if (AppShutdown::GetCurrentShutdownPhase() >=
+        ShutdownPhase::XPCOMShutdownThreads) {
+      // No point in trying to dispatch this if we're already shutting down.
+      return;
+    }
+    java::XPCOMEventTarget::JNIRunnable::GlobalRef r =
+        java::XPCOMEventTarget::JNIRunnable::Ref::From(aJavaRunnable);
+    mTarget->Dispatch(NS_NewRunnableFunction(
+        "XPCOMEventTargetWrapper::DispatchNative",
+        [runnable = std::move(r)]() { runnable->Run(); }));
+  }
+
+  bool IsOnCurrentThread() { return mTarget->IsOnCurrentThread(); }
+
+  static void Init() {
+    java::XPCOMEventTarget::Natives<XPCOMEventTargetWrapper>::Init();
+    CreateWrapper(u"main"_ns, do_GetMainThread());
+    if (XRE_IsParentProcess()) {
+      CreateWrapper(u"launcher"_ns, ipc::GetIPCLauncher());
+    }
+  }
+
+  static void CreateWrapper(mozilla::jni::String::Param aName,
+                            nsCOMPtr<nsIEventTarget> aTarget) {
+    auto java = java::XPCOMEventTarget::New();
+    auto native = MakeUnique<XPCOMEventTargetWrapper>(aTarget.forget());
+    AttachNative(java, std::move(native));
+
+    java::XPCOMEventTarget::SetTarget(aName, java);
+  }
+
+  static void ResolveAndDispatchNative(mozilla::jni::String::Param aName,
+                                       mozilla::jni::Object::Param aRunnable) {
+    java::XPCOMEventTarget::ResolveAndDispatch(aName, aRunnable);
+  }
+
+  explicit XPCOMEventTargetWrapper(already_AddRefed<nsIEventTarget> aTarget)
+      : mTarget(aTarget) {}
+
+ private:
+  nsCOMPtr<nsIEventTarget> mTarget;
+};
+
+nsAppShell::nsAppShell()
+    : mSyncRunFinished(*(sAppShellLock = new Mutex("nsAppShell")),
+                       "nsAppShell.SyncRun"),
+      mSyncRunQuit(false) {
+  {
+    MutexAutoLock lock(*sAppShellLock);
+    sAppShell = this;
+  }
+
+  hal::Init();
+
+  if (!XRE_IsParentProcess()) {
+    if (jni::IsAvailable()) {
+      GeckoThreadSupport::Init();
+      GeckoAppShellSupport::Init();
+      XPCOMEventTargetWrapper::Init();
+      mozilla::widget::Telemetry::Init();
+      mozilla::widget::GeckoTelemetryDelegate::Init();
+
+      if (XRE_IsGPUProcess()) {
+        mozilla::gl::AndroidSurfaceTexture::Init();
+      }
+
+      // Set the corresponding state in GeckoThread.
+      java::GeckoThread::SetState(java::GeckoThread::State::RUNNING());
+    }
+    return;
+  }
+
+  if (jni::IsAvailable()) {
+    ScreenManager& screenManager = ScreenManager::GetSingleton();
+    screenManager.SetHelper(mozilla::MakeUnique<ScreenHelperAndroid>());
+
+    // Initialize JNI and Set the corresponding state in GeckoThread.
+    AndroidBridge::ConstructBridge();
+    GeckoAppShellSupport::Init();
+    GeckoThreadSupport::Init();
+    XPCOMEventTargetWrapper::Init();
+    mozilla::GeckoBatteryManager::Init();
+    mozilla::GeckoNetworkManager::Init();
+    mozilla::GeckoProcessManager::Init();
+    mozilla::GeckoSystemStateListener::Init();
+    mozilla::widget::Telemetry::Init();
+    mozilla::widget::ImageDecoderSupport::Init();
+    mozilla::widget::WebExecutorSupport::Init();
+    mozilla::widget::Base64UtilsSupport::Init();
+    nsWindow::InitNatives();
+    mozilla::gl::AndroidSurfaceTexture::Init();
+    mozilla::widget::GeckoTelemetryDelegate::Init();
+
+    java::GeckoThread::SetState(java::GeckoThread::State::JNI_READY());
+
+    CreateAndroidUiThread();
+  }
+
+  sPowerManagerService = do_GetService(POWERMANAGERSERVICE_CONTRACTID);
+
+  if (sPowerManagerService) {
+    sWakeLockListener = new WakeLockListener();
+  } else {
+    NS_WARNING(
+        "Failed to retrieve PowerManagerService, wakelocks will be broken!");
+  }
+}
+
+nsAppShell::~nsAppShell() {
+  {
+    // Release any thread waiting for a sync call to finish.
+    MutexAutoLock lock(*sAppShellLock);
+    sAppShell = nullptr;
+    mSyncRunFinished.NotifyAll();
+  }
+
+  while (mEventQueue.Pop(/* mayWait */ false)) {
+    NS_WARNING("Discarded event on shutdown");
+  }
+
+  if (sPowerManagerService) {
+    sPowerManagerService->RemoveWakeLockListener(sWakeLockListener);
+
+    sPowerManagerService = nullptr;
+    sWakeLockListener = nullptr;
+  }
+
+  hal::Shutdown();
+
+  if (jni::IsAvailable() && XRE_IsParentProcess()) {
+    DestroyAndroidUiThread();
+    AndroidBridge::DeconstructBridge();
+  }
+}
+
+void nsAppShell::NotifyNativeEvent() { mEventQueue.Signal(); }
+
+nsresult nsAppShell::Init() {
+  nsresult rv = nsBaseAppShell::Init();
+  nsCOMPtr<nsIObserverService> obsServ =
+      mozilla::services::GetObserverService();
+  if (obsServ) {
+    obsServ->AddObserver(this, "browser-delayed-startup-finished", false);
+    obsServ->AddObserver(this, "geckoview-startup-complete", false);
+    obsServ->AddObserver(this, "profile-after-change", false);
+    obsServ->AddObserver(this, "quit-application", false);
+    obsServ->AddObserver(this, "quit-application-granted", false);
+
+    if (XRE_IsParentProcess()) {
+      obsServ->AddObserver(this, "chrome-document-loaded", false);
+    } else {
+      obsServ->AddObserver(this, "content-document-global-created", false);
+      obsServ->AddObserver(this, "geckoview-content-global-transferred", false);
+    }
+  }
+
+  if (sPowerManagerService)
+    sPowerManagerService->AddWakeLockListener(sWakeLockListener);
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsAppShell::Exit(void) {
+  {
+    // Release any thread waiting for a sync call to finish.
+    mozilla::MutexAutoLock shellLock(*sAppShellLock);
+    mSyncRunQuit = true;
+    mSyncRunFinished.NotifyAll();
+  }
+  // We need to ensure no observers stick around after XPCOM shuts down
+  // or we'll see crashes, as the app shell outlives XPConnect.
+  mObserversHash.Clear();
+  return nsBaseAppShell::Exit();
+}
+
+NS_IMETHODIMP
+nsAppShell::Observe(nsISupports* aSubject, const char* aTopic,
+                    const char16_t* aData) {
+  bool removeObserver = false;
+
+  if (!strcmp(aTopic, "browser-delayed-startup-finished")) {
+    NS_CreateServicesFromCategory("browser-delayed-startup-finished", nullptr,
+                                  "browser-delayed-startup-finished");
+  } else if (!strcmp(aTopic, "geckoview-startup-complete")) {
+    if (jni::IsAvailable()) {
+      java::GeckoThread::CheckAndSetState(
+          java::GeckoThread::State::PROFILE_READY(),
+          java::GeckoThread::State::RUNNING());
+    }
+  } else if (!strcmp(aTopic, "profile-after-change")) {
+    if (jni::IsAvailable()) {
+      java::GeckoThread::SetState(java::GeckoThread::State::PROFILE_READY());
+
+      // Gecko on Android follows the Android app model where it never
+      // stops until it is killed by the system or told explicitly to
+      // quit. Therefore, we should *not* exit Gecko when there is no
+      // window or the last window is closed. nsIAppStartup::Quit will
+      // still force Gecko to exit.
+      nsCOMPtr<nsIAppStartup> appStartup = components::AppStartup::Service();
+      if (appStartup) {
+        appStartup->EnterLastWindowClosingSurvivalArea();
+      }
+    }
+    removeObserver = true;
+
+  } else if (!strcmp(aTopic, "chrome-document-loaded")) {
+    // Set the global ready state and enable the window event dispatcher
+    // for this particular GeckoView.
+    nsCOMPtr<dom::Document> doc = do_QueryInterface(aSubject);
+    MOZ_ASSERT(doc);
+    if (const RefPtr<nsWindow> window = nsWindow::From(doc->GetWindow())) {
+      window->OnGeckoViewReady();
+    }
+  } else if (!strcmp(aTopic, "quit-application")) {
+    if (jni::IsAvailable()) {
+      const bool restarting = aData && u"restart"_ns.Equals(aData);
+      java::GeckoThread::SetState(restarting
+                                      ? java::GeckoThread::State::RESTARTING()
+                                      : java::GeckoThread::State::EXITING());
+    }
+    removeObserver = true;
+
+  } else if (!strcmp(aTopic, "quit-application-granted")) {
+    if (jni::IsAvailable()) {
+      // We are told explicitly to quit, perhaps due to
+      // nsIAppStartup::Quit being called. We should release our hold on
+      // nsIAppStartup and let it continue to quit.
+      nsCOMPtr<nsIAppStartup> appStartup = components::AppStartup::Service();
+      if (appStartup) {
+        appStartup->ExitLastWindowClosingSurvivalArea();
+      }
+    }
+    removeObserver = true;
+
+  } else if (!strcmp(aTopic, "content-document-global-created")) {
+    // Associate the PuppetWidget of the newly-created BrowserChild with a
+    // GeckoEditableChild instance.
+    MOZ_ASSERT(!XRE_IsParentProcess());
+
+    nsCOMPtr<mozIDOMWindowProxy> domWindow = do_QueryInterface(aSubject);
+    MOZ_ASSERT(domWindow);
+    nsCOMPtr<nsIWidget> domWidget = widget::WidgetUtils::DOMWindowToWidget(
+        nsPIDOMWindowOuter::From(domWindow));
+    NS_ENSURE_TRUE(domWidget, NS_OK);
+
+    widget::GeckoEditableSupport::SetOnBrowserChild(
+        domWidget->GetOwningBrowserChild());
+
+  } else if (!strcmp(aTopic, "geckoview-content-global-transferred")) {
+    // We're transferring to a new GeckoEditableParent, so notify the
+    // existing GeckoEditableChild instance associated with the docshell.
+    nsCOMPtr<nsIDocShell> docShell = do_QueryInterface(aSubject);
+    widget::GeckoEditableSupport::SetOnBrowserChild(
+        dom::BrowserChild::GetFrom(docShell));
+  } else {
+    return nsBaseAppShell::Observe(aSubject, aTopic, aData);
+  }
+
+  if (removeObserver) {
+    nsCOMPtr<nsIObserverService> obsServ =
+        mozilla::services::GetObserverService();
+    if (obsServ) {
+      obsServ->RemoveObserver(this, aTopic);
+    }
+  }
+  return NS_OK;
+}
+
+bool nsAppShell::ProcessNextNativeEvent(bool mayWait) {
+  EVLOG("nsAppShell::ProcessNextNativeEvent %d", mayWait);
+
+  AUTO_PROFILER_LABEL("nsAppShell::ProcessNextNativeEvent", OTHER);
+
+  mozilla::UniquePtr<Event> curEvent;
+
+  {
+    curEvent = mEventQueue.Pop(/* mayWait */ false);
+
+    if (!curEvent && mayWait) {
+      // This processes messages in the Android Looper. Note that we only
+      // get here if the normal Gecko event loop has been awoken
+      // (bug 750713). Looper messages effectively have the lowest
+      // priority because we only process them before we're about to
+      // wait for new events.
+      if (jni::IsAvailable() && XRE_IsParentProcess() &&
+          AndroidBridge::Bridge()->PumpMessageLoop()) {
+        return true;
+      }
+
+      AUTO_PROFILER_LABEL("nsAppShell::ProcessNextNativeEvent:Wait", IDLE);
+      mozilla::BackgroundHangMonitor().NotifyWait();
+
+      curEvent = mEventQueue.Pop(/* mayWait */ true);
+    }
+  }
+
+  if (!curEvent) return false;
+
+  mozilla::BackgroundHangMonitor().NotifyActivity();
+
+  curEvent->Run();
+  return true;
+}
+
+bool nsAppShell::SyncRunEvent(
+    Event&& event, UniquePtr<Event> (*eventFactory)(UniquePtr<Event>&&),
+    const TimeDuration timeout) {
+  // Perform the call on the Gecko thread in a separate lambda, and wait
+  // on the monitor on the current thread.
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  // This is the lock to check that app shell is still alive,
+  // and to wait on for the sync call to complete.
+  mozilla::MutexAutoLock shellLock(*sAppShellLock);
+  nsAppShell* const appShell = sAppShell;
+
+  if (MOZ_UNLIKELY(!appShell)) {
+    // Post-shutdown.
+    return false;
+  }
+
+  bool finished = false;
+  auto runAndNotify = [&event, &finished] {
+    nsAppShell* const appShell = nsAppShell::Get();
+    if (MOZ_UNLIKELY(!appShell || appShell->mSyncRunQuit)) {
+      return false;
+    }
+    event.Run();
+    finished = true;
+    mozilla::MutexAutoLock shellLock(*sAppShellLock);
+    appShell->mSyncRunFinished.NotifyAll();
+    return finished;
+  };
+
+  UniquePtr<Event> runAndNotifyEvent =
+      mozilla::MakeUnique<LambdaEvent<decltype(runAndNotify)>>(
+          std::move(runAndNotify));
+
+  if (eventFactory) {
+    runAndNotifyEvent = (*eventFactory)(std::move(runAndNotifyEvent));
+  }
+
+  appShell->mEventQueue.Post(std::move(runAndNotifyEvent));
+
+  while (!finished && MOZ_LIKELY(sAppShell && !sAppShell->mSyncRunQuit)) {
+    appShell->mSyncRunFinished.Wait(timeout);
+  }
+
+  return finished;
+}
+
+already_AddRefed<nsIURI> nsAppShell::ResolveURI(const nsCString& aUriStr) {
+  nsCOMPtr<nsIIOService> ioServ = do_GetIOService();
+  nsCOMPtr<nsIURI> uri;
+
+  if (NS_SUCCEEDED(
+          ioServ->NewURI(aUriStr, nullptr, nullptr, getter_AddRefs(uri)))) {
+    return uri.forget();
+  }
+
+  nsCOMPtr<nsIURIFixup> fixup = components::URIFixup::Service();
+  nsCOMPtr<nsIURIFixupInfo> fixupInfo;
+  if (fixup &&
+      NS_SUCCEEDED(fixup->GetFixupURIInfo(aUriStr, nsIURIFixup::FIXUP_FLAG_NONE,
+                                          getter_AddRefs(fixupInfo))) &&
+      NS_SUCCEEDED(fixupInfo->GetPreferredURI(getter_AddRefs(uri)))) {
+    return uri.forget();
+  }
+  return nullptr;
+}
+
+nsresult nsAppShell::AddObserver(const nsAString& aObserverKey,
+                                 nsIObserver* aObserver) {
+  NS_ASSERTION(aObserver != nullptr,
+               "nsAppShell::AddObserver: aObserver is null!");
+  mObserversHash.InsertOrUpdate(aObserverKey, aObserver);
+  return NS_OK;
+}
+
+// Used by IPC code
+namespace mozilla {
+
+bool ProcessNextEvent() {
+  nsAppShell* const appShell = nsAppShell::Get();
+  if (!appShell) {
+    return false;
+  }
+
+  return appShell->ProcessNextNativeEvent(true) ? true : false;
+}
+
+void NotifyEvent() {
+  nsAppShell* const appShell = nsAppShell::Get();
+  if (!appShell) {
+    return;
+  }
+  appShell->NotifyNativeEvent();
+}
+
+}  // namespace mozilla
diff --git a/widget/android/nsAppShell.h b/widget/android/nsAppShell.h
new file mode 100644
index 0000000000..9b1dc5ca14
--- /dev/null
+++ b/widget/android/nsAppShell.h
@@ -0,0 +1,217 @@
+/* -*- Mode: c++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsAppShell_h__
+#define nsAppShell_h__
+
+#include <time.h>
+
+#include <type_traits>
+#include <utility>
+
+#include "mozilla/BackgroundHangMonitor.h"
+#include "mozilla/LinkedList.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/TimeStamp.h"  // for mozilla::TimeDuration
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Unused.h"
+#include "mozilla/jni/Natives.h"
+#include "nsBaseAppShell.h"
+#include "nsCOMPtr.h"
+#include "nsIAndroidBridge.h"
+#include "nsInterfaceHashtable.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+bool ProcessNextEvent();
+void NotifyEvent();
+}  // namespace mozilla
+
+class nsWindow;
+
+class nsAppShell : public nsBaseAppShell {
+ public:
+  struct Event : mozilla::LinkedListElement<Event> {
+    static uint64_t GetTime() {
+      timespec time;
+      if (clock_gettime(CLOCK_MONOTONIC, &time)) {
+        return 0ull;
+      }
+      return uint64_t(time.tv_sec) * 1000000000ull + time.tv_nsec;
+    }
+
+    uint64_t mPostTime{0};
+
+    bool HasSameTypeAs(const Event* other) const {
+      // Compare vtable addresses to determine same type.
+      return *reinterpret_cast<const uintptr_t*>(this) ==
+             *reinterpret_cast<const uintptr_t*>(other);
+    }
+
+    virtual ~Event() {}
+    virtual void Run() = 0;
+
+    virtual void PostTo(mozilla::LinkedList<Event>& queue) {
+      queue.insertBack(this);
+    }
+
+    virtual bool IsUIEvent() const { return false; }
+  };
+
+  template <typename T>
+  class LambdaEvent : public Event {
+   protected:
+    T lambda;
+
+   public:
+    explicit LambdaEvent(T&& l) : lambda(std::move(l)) {}
+    void Run() override { lambda(); }
+  };
+
+  class ProxyEvent : public Event {
+   protected:
+    mozilla::UniquePtr<Event> baseEvent;
+
+   public:
+    explicit ProxyEvent(mozilla::UniquePtr<Event>&& event)
+        : baseEvent(std::move(event)) {}
+
+    void PostTo(mozilla::LinkedList<Event>& queue) override {
+      baseEvent->PostTo(queue);
+    }
+
+    void Run() override { baseEvent->Run(); }
+  };
+
+  static nsAppShell* Get() {
+    MOZ_ASSERT(NS_IsMainThread());
+    return sAppShell;
+  }
+
+  nsAppShell();
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIOBSERVER
+
+  nsresult Init();
+
+  void NotifyNativeEvent();
+  bool ProcessNextNativeEvent(bool mayWait) override;
+
+  // Post a subclass of Event.
+  // e.g. PostEvent(mozilla::MakeUnique<MyEvent>());
+  template <typename T, typename D>
+  static void PostEvent(mozilla::UniquePtr<T, D>&& event) {
+    mozilla::MutexAutoLock lock(*sAppShellLock);
+    if (!sAppShell) {
+      return;
+    }
+    sAppShell->mEventQueue.Post(std::move(event));
+  }
+
+  // Post a event that will call a lambda
+  // e.g. PostEvent([=] { /* do something */ });
+  template <typename T>
+  static void PostEvent(T&& lambda) {
+    mozilla::MutexAutoLock lock(*sAppShellLock);
+    if (!sAppShell) {
+      return;
+    }
+    sAppShell->mEventQueue.Post(
+        mozilla::MakeUnique<LambdaEvent<T>>(std::move(lambda)));
+  }
+
+  // Post a event and wait for it to finish running on the Gecko thread.
+  static bool SyncRunEvent(
+      Event&& event,
+      mozilla::UniquePtr<Event> (*eventFactory)(mozilla::UniquePtr<Event>&&) =
+          nullptr,
+      const mozilla::TimeDuration timeout = mozilla::TimeDuration::Forever());
+
+  template <typename T>
+  static std::enable_if_t<!std::is_base_of<Event, T>::value, void> SyncRunEvent(
+      T&& lambda) {
+    SyncRunEvent(LambdaEvent<T>(std::forward<T>(lambda)));
+  }
+
+  static already_AddRefed<nsIURI> ResolveURI(const nsCString& aUriStr);
+
+ protected:
+  static nsAppShell* sAppShell;
+  static mozilla::StaticAutoPtr<mozilla::Mutex> sAppShellLock;
+
+  virtual ~nsAppShell();
+
+  NS_IMETHOD Exit() override;
+  nsresult AddObserver(const nsAString& aObserverKey, nsIObserver* aObserver);
+
+  class NativeCallbackEvent : public Event {
+    // Capturing the nsAppShell instance is safe because if the app
+    // shell is destroyed, this lambda will not be called either.
+    nsAppShell* const appShell;
+
+   public:
+    explicit NativeCallbackEvent(nsAppShell* as) : appShell(as) {}
+    void Run() override { appShell->NativeEventCallback(); }
+  };
+
+  void ScheduleNativeEventCallback() override {
+    mEventQueue.Post(mozilla::MakeUnique<NativeCallbackEvent>(this));
+  }
+
+  class Queue {
+   private:
+    mozilla::Monitor mMonitor MOZ_UNANNOTATED;
+    mozilla::LinkedList<Event> mQueue;
+
+   public:
+    enum { LATENCY_UI, LATENCY_OTHER, LATENCY_COUNT };
+    Queue() : mMonitor("nsAppShell.Queue") {}
+
+    void Signal() {
+      mozilla::MonitorAutoLock lock(mMonitor);
+      lock.NotifyAll();
+    }
+
+    void Post(mozilla::UniquePtr<Event>&& event) {
+      MOZ_ASSERT(event && !event->isInList());
+
+      mozilla::MonitorAutoLock lock(mMonitor);
+      event->PostTo(mQueue);
+      if (event->isInList()) {
+        event->mPostTime = Event::GetTime();
+        // Ownership of event object transfers to the queue.
+        mozilla::Unused << event.release();
+      }
+      lock.NotifyAll();
+    }
+
+    mozilla::UniquePtr<Event> Pop(bool mayWait) {
+      mozilla::MonitorAutoLock lock(mMonitor);
+
+      if (mayWait && mQueue.isEmpty()) {
+        lock.Wait();
+      }
+
+      // Ownership of event object transfers to the return value.
+      mozilla::UniquePtr<Event> event(mQueue.popFirst());
+      if (!event || !event->mPostTime) {
+        return event;
+      }
+
+      return event;
+    }
+
+  } mEventQueue;
+
+ private:
+  mozilla::CondVar mSyncRunFinished;
+  bool mSyncRunQuit;
+
+  nsInterfaceHashtable<nsStringHashKey, nsIObserver> mObserversHash;
+};
+
+#endif  // nsAppShell_h__
diff --git a/widget/android/nsClipboard.cpp b/widget/android/nsClipboard.cpp
new file mode 100644
index 0000000000..c2a03dd540
--- /dev/null
+++ b/widget/android/nsClipboard.cpp
@@ -0,0 +1,214 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/java/ClipboardWrappers.h"
+#include "mozilla/java/GeckoAppShellWrappers.h"
+#include "nsClipboard.h"
+#include "nsISupportsPrimitives.h"
+#include "nsCOMPtr.h"
+#include "nsComponentManagerUtils.h"
+#include "nsMemory.h"
+#include "nsStringStream.h"
+#include "nsPrimitiveHelpers.h"
+
+using namespace mozilla;
+
+NS_IMPL_ISUPPORTS_INHERITED0(nsClipboard, nsBaseClipboard)
+
+/* The Android clipboard only supports text and doesn't support mime types
+ * so we assume all clipboard data is text/plain for now. Documentation
+ * indicates that support for other data types is planned for future
+ * releases.
+ */
+
+nsClipboard::nsClipboard()
+    : nsBaseClipboard(mozilla::dom::ClipboardCapabilities(
+          false /* supportsSelectionClipboard */,
+          false /* supportsFindClipboard */,
+          false /* supportsSelectionCache */)) {
+  java::Clipboard::StartTrackingClipboardData(
+      java::GeckoAppShell::GetApplicationContext());
+}
+
+nsClipboard::~nsClipboard() {
+  java::Clipboard::StopTrackingClipboardData(
+      java::GeckoAppShell::GetApplicationContext());
+}
+
+// static
+nsresult nsClipboard::GetTextFromTransferable(nsITransferable* aTransferable,
+                                              nsString& aText,
+                                              nsString& aHTML) {
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanImport(flavors);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  for (auto& flavorStr : flavors) {
+    if (flavorStr.EqualsLiteral(kTextMime)) {
+      nsCOMPtr<nsISupports> item;
+      nsresult rv =
+          aTransferable->GetTransferData(kTextMime, getter_AddRefs(item));
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        continue;
+      }
+      nsCOMPtr<nsISupportsString> supportsString = do_QueryInterface(item);
+      if (supportsString) {
+        supportsString->GetData(aText);
+      }
+    } else if (flavorStr.EqualsLiteral(kHTMLMime)) {
+      nsCOMPtr<nsISupports> item;
+      nsresult rv =
+          aTransferable->GetTransferData(kHTMLMime, getter_AddRefs(item));
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        continue;
+      }
+      nsCOMPtr<nsISupportsString> supportsString = do_QueryInterface(item);
+      if (supportsString) {
+        supportsString->GetData(aHTML);
+      }
+    }
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  if (!jni::IsAvailable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsString text;
+  nsString html;
+  nsresult rv = GetTextFromTransferable(aTransferable, text, html);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  if (!html.IsEmpty() &&
+      java::Clipboard::SetHTML(java::GeckoAppShell::GetApplicationContext(),
+                               text, html)) {
+    return NS_OK;
+  }
+  if (!text.IsEmpty() &&
+      java::Clipboard::SetText(java::GeckoAppShell::GetApplicationContext(),
+                               text)) {
+    return NS_OK;
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  if (!jni::IsAvailable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsTArray<nsCString> flavors;
+  aTransferable->FlavorsTransferableCanImport(flavors);
+
+  for (auto& flavorStr : flavors) {
+    if (flavorStr.EqualsLiteral(kTextMime) ||
+        flavorStr.EqualsLiteral(kHTMLMime)) {
+      auto text = java::Clipboard::GetTextData(
+          java::GeckoAppShell::GetApplicationContext(), flavorStr);
+      if (!text) {
+        continue;
+      }
+      nsString buffer = text->ToString();
+      if (buffer.IsEmpty()) {
+        continue;
+      }
+      nsCOMPtr<nsISupports> wrapper;
+      nsPrimitiveHelpers::CreatePrimitiveForData(flavorStr, buffer.get(),
+                                                 buffer.Length() * 2,
+                                                 getter_AddRefs(wrapper));
+      if (wrapper) {
+        aTransferable->SetTransferData(flavorStr.get(), wrapper);
+        return NS_OK;
+      }
+      continue;
+    }
+
+    mozilla::jni::ByteArray::LocalRef bytes;
+    nsresult rv = java::Clipboard::GetRawData(flavorStr, &bytes);
+    if (NS_FAILED(rv) || !bytes) {
+      continue;
+    }
+    nsCOMPtr<nsIInputStream> byteStream;
+    rv = NS_NewByteInputStream(
+        getter_AddRefs(byteStream),
+        mozilla::Span(
+            reinterpret_cast<const char*>(bytes->GetElements().Elements()),
+            bytes->Length()),
+        NS_ASSIGNMENT_COPY);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      continue;
+    }
+    rv = aTransferable->SetTransferData(flavorStr.get(), byteStream);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      continue;
+    }
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+nsresult nsClipboard::EmptyNativeClipboardData(int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  if (!jni::IsAvailable()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  java::Clipboard::Clear(java::GeckoAppShell::GetApplicationContext());
+
+  return NS_OK;
+}
+
+mozilla::Result<int32_t, nsresult>
+nsClipboard::GetNativeClipboardSequenceNumber(int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  if (!jni::IsAvailable()) {
+    return Err(NS_ERROR_NOT_AVAILABLE);
+  }
+
+  return java::Clipboard::GetSequenceNumber(
+      java::GeckoAppShell::GetApplicationContext());
+}
+
+mozilla::Result<bool, nsresult>
+nsClipboard::HasNativeClipboardDataMatchingFlavors(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  if (!jni::IsAvailable()) {
+    return Err(NS_ERROR_NOT_AVAILABLE);
+  }
+
+  for (auto& flavor : aFlavorList) {
+    if (java::Clipboard::HasData(java::GeckoAppShell::GetApplicationContext(),
+                                 NS_ConvertASCIItoUTF16(flavor))) {
+      return true;
+    }
+  }
+
+  return false;
+}
diff --git a/widget/android/nsClipboard.h b/widget/android/nsClipboard.h
new file mode 100644
index 0000000000..d3a45d47e5
--- /dev/null
+++ b/widget/android/nsClipboard.h
@@ -0,0 +1,36 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NS_CLIPBOARD_H
+#define NS_CLIPBOARD_H
+
+#include "nsBaseClipboard.h"
+
+class nsClipboard final : public nsBaseClipboard {
+ private:
+  ~nsClipboard();
+
+ public:
+  nsClipboard();
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  static nsresult GetTextFromTransferable(nsITransferable* aTransferable,
+                                          nsString& aText, nsString& aHTML);
+
+ protected:
+  // Implement the native clipboard behavior.
+  NS_IMETHOD SetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) override;
+  NS_IMETHOD GetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) override;
+  nsresult EmptyNativeClipboardData(int32_t aWhichClipboard) override;
+  mozilla::Result<int32_t, nsresult> GetNativeClipboardSequenceNumber(
+      int32_t aWhichClipboard) override;
+  mozilla::Result<bool, nsresult> HasNativeClipboardDataMatchingFlavors(
+      const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) override;
+};
+
+#endif
diff --git a/widget/android/nsDeviceContextAndroid.cpp b/widget/android/nsDeviceContextAndroid.cpp
new file mode 100644
index 0000000000..e6643ef9b3
--- /dev/null
+++ b/widget/android/nsDeviceContextAndroid.cpp
@@ -0,0 +1,100 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsDeviceContextAndroid.h"
+
+#include "mozilla/gfx/PrintTargetPDF.h"
+#include "mozilla/RefPtr.h"
+#include "nsComponentManagerUtils.h"
+#include "nsString.h"
+#include "nsIFile.h"
+#include "nsIFileStreams.h"
+#include "nsIPrintSettings.h"
+#include "nsIFileStreams.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsAnonymousTemporaryFile.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+
+NS_IMPL_ISUPPORTS(nsDeviceContextSpecAndroid, nsIDeviceContextSpec)
+
+nsDeviceContextSpecAndroid::~nsDeviceContextSpecAndroid() {
+  if (mTempFile) {
+    mTempFile->Remove(false);
+  }
+}
+
+already_AddRefed<PrintTarget> nsDeviceContextSpecAndroid::MakePrintTarget() {
+  double width, height;
+  mPrintSettings->GetEffectiveSheetSize(&width, &height);
+
+  // convert twips to points
+  width /= TWIPS_PER_POINT_FLOAT;
+  height /= TWIPS_PER_POINT_FLOAT;
+
+  auto stream = [&]() -> nsCOMPtr<nsIOutputStream> {
+    if (mPrintSettings->GetOutputDestination() ==
+        nsIPrintSettings::kOutputDestinationStream) {
+      nsCOMPtr<nsIOutputStream> out;
+      mPrintSettings->GetOutputStream(getter_AddRefs(out));
+      return out;
+    }
+    if (NS_FAILED(
+            NS_OpenAnonymousTemporaryNsIFile(getter_AddRefs(mTempFile)))) {
+      return nullptr;
+    }
+    // Print to printer not supported...
+    nsCOMPtr<nsIFileOutputStream> s =
+        do_CreateInstance("@mozilla.org/network/file-output-stream;1");
+    if (NS_FAILED(s->Init(mTempFile, -1, -1, 0))) {
+      return nullptr;
+    }
+    return s;
+  }();
+
+  return PrintTargetPDF::CreateOrNull(stream, IntSize::Ceil(width, height));
+}
+
+NS_IMETHODIMP
+nsDeviceContextSpecAndroid::Init(nsIPrintSettings* aPS, bool aIsPrintPreview) {
+  mPrintSettings = aPS;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDeviceContextSpecAndroid::BeginDocument(const nsAString& aTitle,
+                                          const nsAString& aPrintToFileName,
+                                          int32_t aStartPage,
+                                          int32_t aEndPage) {
+  return NS_OK;
+}
+
+RefPtr<PrintEndDocumentPromise> nsDeviceContextSpecAndroid::EndDocument() {
+  return nsIDeviceContextSpec::EndDocumentPromiseFromResult(DoEndDocument(),
+                                                            __func__);
+}
+
+NS_IMETHODIMP
+nsDeviceContextSpecAndroid::DoEndDocument() {
+  if (mPrintSettings->GetOutputDestination() ==
+          nsIPrintSettings::kOutputDestinationFile &&
+      mTempFile) {
+    nsAutoString targetPath;
+    mPrintSettings->GetToFileName(targetPath);
+    nsCOMPtr<nsIFile> destFile;
+    MOZ_TRY(NS_NewLocalFile(targetPath, false, getter_AddRefs(destFile)));
+    nsAutoString destLeafName;
+    MOZ_TRY(destFile->GetLeafName(destLeafName));
+
+    nsCOMPtr<nsIFile> destDir;
+    MOZ_TRY(destFile->GetParent(getter_AddRefs(destDir)));
+
+    MOZ_TRY(mTempFile->MoveTo(destDir, destLeafName));
+    destFile->SetPermissions(0666);
+
+    mTempFile = nullptr;
+  }
+  return NS_OK;
+}
diff --git a/widget/android/nsDeviceContextAndroid.h b/widget/android/nsDeviceContextAndroid.h
new file mode 100644
index 0000000000..094f391151
--- /dev/null
+++ b/widget/android/nsDeviceContextAndroid.h
@@ -0,0 +1,36 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef nsDeviceContextAndroid_h__
+#define nsDeviceContextAndroid_h__
+
+#include "nsIDeviceContextSpec.h"
+#include "nsCOMPtr.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/gfx/PrintPromise.h"
+
+class nsDeviceContextSpecAndroid final : public nsIDeviceContextSpec {
+ private:
+  virtual ~nsDeviceContextSpecAndroid();
+
+ public:
+  using IntSize = mozilla::gfx::IntSize;
+
+  NS_DECL_ISUPPORTS
+
+  already_AddRefed<PrintTarget> MakePrintTarget() final;
+
+  NS_IMETHOD Init(nsIPrintSettings* aPS, bool aIsPrintPreview) override;
+  NS_IMETHOD BeginDocument(const nsAString& aTitle,
+                           const nsAString& aPrintToFileName,
+                           int32_t aStartPage, int32_t aEndPage) override;
+  RefPtr<mozilla::gfx::PrintEndDocumentPromise> EndDocument() override;
+  NS_IMETHOD BeginPage(const IntSize& aSizeInPoints) override { return NS_OK; }
+  NS_IMETHOD EndPage() override { return NS_OK; }
+
+ private:
+  nsresult DoEndDocument();
+  nsCOMPtr<nsIFile> mTempFile;
+};
+#endif  // nsDeviceContextAndroid_h__
diff --git a/widget/android/nsDragService.cpp b/widget/android/nsDragService.cpp
new file mode 100644
index 0000000000..8f12ab65e3
--- /dev/null
+++ b/widget/android/nsDragService.cpp
@@ -0,0 +1,272 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsDragService.h"
+
+#include "AndroidGraphics.h"
+#include "AndroidWidgetUtils.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/java/GeckoDragAndDropWrappers.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/ScopeExit.h"
+#include "nsArrayUtils.h"
+#include "nsClipboard.h"
+#include "nsComponentManagerUtils.h"
+#include "nsIArray.h"
+#include "nsITransferable.h"
+#include "nsPrimitiveHelpers.h"
+#include "nsViewManager.h"
+#include "nsWindow.h"
+
+NS_IMPL_ISUPPORTS_INHERITED0(nsDragService, nsBaseDragService)
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+StaticRefPtr<nsDragService> sDragServiceInstance;
+
+/* static */
+already_AddRefed<nsDragService> nsDragService::GetInstance() {
+  if (!sDragServiceInstance) {
+    sDragServiceInstance = new nsDragService();
+    ClearOnShutdown(&sDragServiceInstance);
+  }
+
+  RefPtr<nsDragService> service = sDragServiceInstance.get();
+  return service.forget();
+}
+
+static nsWindow* GetWindow(dom::Document* aDocument) {
+  if (!aDocument) {
+    return nullptr;
+  }
+
+  PresShell* presShell = aDocument->GetPresShell();
+  if (!presShell) {
+    return nullptr;
+  }
+
+  RefPtr<nsViewManager> vm = presShell->GetViewManager();
+  if (!vm) {
+    return nullptr;
+  }
+
+  nsCOMPtr<nsIWidget> widget = vm->GetRootWidget();
+  if (!widget) {
+    return nullptr;
+  }
+
+  RefPtr<nsWindow> window = nsWindow::From(widget);
+  return window.get();
+}
+
+nsresult nsDragService::InvokeDragSessionImpl(
+    nsIArray* aTransferableArray, const Maybe<CSSIntRegion>& aRegion,
+    uint32_t aActionType) {
+  if (jni::GetAPIVersion() < 24) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  uint32_t count = 0;
+  aTransferableArray->GetLength(&count);
+  if (count != 1) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsITransferable> transferable =
+      do_QueryElementAt(aTransferableArray, 0);
+
+  nsAutoString html;
+  nsAutoString text;
+  nsresult rv = nsClipboard::GetTextFromTransferable(transferable, text, html);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  java::GeckoDragAndDrop::SetDragData(text, html);
+
+  if (nsWindow* window = GetWindow(mSourceDocument)) {
+    mTransferable = transferable;
+
+    nsBaseDragService::StartDragSession();
+    nsBaseDragService::OpenDragPopup();
+
+    auto bitmap = CreateDragImage(mSourceNode, aRegion);
+    window->StartDragAndDrop(bitmap);
+
+    return NS_OK;
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsDragService::GetData(nsITransferable* aTransferable, uint32_t aItem) {
+  if (!aTransferable) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanImport(flavors);
+  if (NS_FAILED(rv)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  for (const auto& flavor : flavors) {
+    nsCOMPtr<nsISupports> data;
+    rv = mTransferable->GetTransferData(flavor.get(), getter_AddRefs(data));
+    if (NS_FAILED(rv)) {
+      continue;
+    }
+    rv = aTransferable->SetTransferData(flavor.get(), data);
+    if (NS_SUCCEEDED(rv)) {
+      return rv;
+    }
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsDragService::GetNumDropItems(uint32_t* aNumItems) {
+  if (mTransferable) {
+    *aNumItems = 1;
+    return NS_OK;
+  }
+  *aNumItems = 0;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDragService::IsDataFlavorSupported(const char* aDataFlavor, bool* _retval) {
+  *_retval = false;
+
+  nsDependentCString dataFlavor(aDataFlavor);
+  auto logging = MakeScopeExit([&] {
+    MOZ_DRAGSERVICE_LOG("IsDataFlavorSupported: %s is%s found", aDataFlavor,
+                        *_retval ? "" : " not");
+  });
+
+  nsTArray<nsCString> flavors;
+  nsresult rv = mTransferable->FlavorsTransferableCanImport(flavors);
+  if (NS_FAILED(rv)) {
+    return NS_OK;
+  }
+
+  for (const auto& flavor : flavors) {
+    if (dataFlavor.Equals(flavor)) {
+      *_retval = true;
+      return NS_OK;
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDragService::EndDragSession(bool aDoneDrag, uint32_t aKeyModifiers) {
+  java::GeckoDragAndDrop::EndDragSession();
+
+  nsresult rv = nsBaseDragService::EndDragSession(aDoneDrag, aKeyModifiers);
+  mTransferable = nullptr;
+  return rv;
+}
+
+NS_IMETHODIMP
+nsDragService::UpdateDragImage(nsINode* aImage, int32_t aImageX,
+                               int32_t aImageY) {
+  nsBaseDragService::UpdateDragImage(aImage, aImageX, aImageY);
+  auto bitmap = CreateDragImage(mSourceNode, Nothing());
+
+  if (nsWindow* window = GetWindow(mSourceDocument)) {
+    window->UpdateDragImage(bitmap);
+  }
+
+  return NS_OK;
+}
+
+bool nsDragService::MustUpdateDataTransfer(EventMessage aMessage) {
+  // Android's drag and drop API sets drop item in drop event.
+  // So we have to invalidate data transfer cache on drop event.
+  return aMessage == eDrop;
+}
+
+java::sdk::Bitmap::LocalRef nsDragService::CreateDragImage(
+    nsINode* aNode, const Maybe<CSSIntRegion>& aRegion) {
+  LayoutDeviceIntRect dragRect;
+  RefPtr<SourceSurface> surface;
+  nsPresContext* pc;
+  DrawDrag(aNode, aRegion, mScreenPosition, &dragRect, &surface, &pc);
+  if (!surface) {
+    return nullptr;
+  }
+
+  RefPtr<DataSourceSurface> destDataSurface =
+      AndroidWidgetUtils::GetDataSourceSurfaceForAndroidBitmap(
+          surface, &dragRect, dragRect.width * 4);
+  if (!destDataSurface) {
+    return nullptr;
+  }
+
+  DataSourceSurface::ScopedMap destMap(destDataSurface,
+                                       DataSourceSurface::READ);
+
+  java::sdk::Bitmap::LocalRef bitmap;
+  auto pixels = mozilla::jni::ByteBuffer::New(
+      reinterpret_cast<int8_t*>(destMap.GetData()),
+      destMap.GetStride() * destDataSurface->GetSize().height);
+  bitmap = java::sdk::Bitmap::CreateBitmap(
+      dragRect.width, dragRect.height, java::sdk::Bitmap::Config::ARGB_8888());
+  bitmap->CopyPixelsFromBuffer(pixels);
+  return bitmap;
+}
+
+void nsDragService::SetData(nsITransferable* aTransferable) {
+  mTransferable = aTransferable;
+  // Reset DataTransfer
+  mDataTransfer = nullptr;
+}
+
+// static
+void nsDragService::SetDropData(
+    mozilla::java::GeckoDragAndDrop::DropData::Param aDropData) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  RefPtr<nsDragService> dragService = nsDragService::GetInstance();
+  if (!dragService) {
+    return;
+  }
+
+  if (!aDropData) {
+    dragService->SetData(nullptr);
+    return;
+  }
+
+  nsCString mime(aDropData->MimeType()->ToCString());
+
+  if (mime.EqualsLiteral("application/x-moz-draganddrop")) {
+    // The drop data isn't changed.
+    return;
+  }
+
+  if (!mime.EqualsLiteral("text/plain") && !mime.EqualsLiteral("text/html")) {
+    // Not supported data.
+    dragService->SetData(nullptr);
+    return;
+  }
+
+  nsString buffer(aDropData->Text()->ToString());
+  nsCOMPtr<nsISupports> wrapper;
+  nsPrimitiveHelpers::CreatePrimitiveForData(
+      mime, buffer.get(), buffer.Length() * 2, getter_AddRefs(wrapper));
+  if (!wrapper) {
+    dragService->SetData(nullptr);
+    return;
+  }
+  nsCOMPtr<nsITransferable> transferable =
+      do_CreateInstance("@mozilla.org/widget/transferable;1");
+  transferable->Init(nullptr);
+  transferable->SetTransferData(mime.get(), wrapper);
+  dragService->SetData(transferable);
+}
diff --git a/widget/android/nsDragService.h b/widget/android/nsDragService.h
new file mode 100644
index 0000000000..5e3a32ef3d
--- /dev/null
+++ b/widget/android/nsDragService.h
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsDragService_h__
+#define nsDragService_h__
+
+#include "nsBaseDragService.h"
+
+#include "AndroidGraphics.h"
+#include "mozilla/java/GeckoDragAndDropNatives.h"
+
+class nsITransferable;
+
+class nsDragService final : public nsBaseDragService {
+ public:
+  nsDragService() = default;
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  static already_AddRefed<nsDragService> GetInstance();
+
+  // nsIDragSession
+  NS_IMETHOD GetData(nsITransferable* aTransferable, uint32_t anItem) override;
+  NS_IMETHOD GetNumDropItems(uint32_t* aNumItems) override;
+  NS_IMETHOD IsDataFlavorSupported(const char* aDataFlavor,
+                                   bool* _retval) override;
+  MOZ_CAN_RUN_SCRIPT NS_IMETHOD EndDragSession(bool aDoneDrag,
+                                               uint32_t aKeyModifiers) override;
+  NS_IMETHOD
+  UpdateDragImage(nsINode* aImage, int32_t aImageX, int32_t aImageY) override;
+  virtual bool MustUpdateDataTransfer(mozilla::EventMessage aMessage) override;
+
+  void SetData(nsITransferable* aTransferable);
+
+  static void SetDropData(
+      mozilla::java::GeckoDragAndDrop::DropData::Param aDropData);
+
+ protected:
+  virtual ~nsDragService() = default;
+
+  // nsBaseDragService
+  MOZ_CAN_RUN_SCRIPT nsresult
+  InvokeDragSessionImpl(nsIArray* anArrayTransferables,
+                        const mozilla::Maybe<mozilla::CSSIntRegion>& aRegion,
+                        uint32_t aActionType) override;
+
+ private:
+  mozilla::java::sdk::Bitmap::LocalRef CreateDragImage(
+      nsINode* aNode, const mozilla::Maybe<mozilla::CSSIntRegion>& aRegion);
+
+  // our source data items
+  nsCOMPtr<nsITransferable> mTransferable;
+};
+
+#endif  // nsDragService_h__
diff --git a/widget/android/nsIAndroidBridge.idl b/widget/android/nsIAndroidBridge.idl
new file mode 100644
index 0000000000..b30ed60d77
--- /dev/null
+++ b/widget/android/nsIAndroidBridge.idl
@@ -0,0 +1,58 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface mozIDOMWindowProxy;
+
+[scriptable, uuid(e64c39b8-b8ec-477d-aef5-89d517ff9219)]
+interface nsIAndroidEventCallback : nsISupports
+{
+  [implicit_jscontext]
+  void onSuccess([optional] in jsval data);
+  [implicit_jscontext]
+  void onError([optional] in jsval data);
+};
+
+[scriptable, function, uuid(819ee2db-d3b8-46dd-a476-40f89c49133c)]
+interface nsIAndroidEventFinalizer : nsISupports
+{
+  void onFinalize();
+};
+
+[scriptable, function, uuid(73569a75-78eb-4c7f-82b9-2d4f5ccf44c3)]
+interface nsIAndroidEventListener : nsISupports
+{
+  void onEvent(in AString event,
+               [optional] in jsval data,
+               [optional] in nsIAndroidEventCallback callback);
+};
+
+[scriptable, uuid(e98bf792-4145-411e-b298-8219d9b03817)]
+interface nsIAndroidEventDispatcher : nsISupports
+{
+  [implicit_jscontext]
+  void dispatch(in jsval event,
+                [optional] in jsval data,
+                [optional] in nsIAndroidEventCallback callback,
+                [optional] in nsIAndroidEventFinalizer finalizer);
+  [implicit_jscontext]
+  void registerListener(in nsIAndroidEventListener listener,
+                        in jsval events);
+  [implicit_jscontext]
+  void unregisterListener(in nsIAndroidEventListener listener,
+                          in jsval events);
+};
+
+[scriptable, uuid(60a78a94-6117-432f-9d49-304913a931c5)]
+interface nsIAndroidView : nsIAndroidEventDispatcher
+{
+  [implicit_jscontext] readonly attribute jsval initData;
+};
+
+[scriptable, uuid(1beb70d3-70f3-4742-98cc-a3d301b26c0c)]
+interface nsIAndroidBridge : nsIAndroidEventDispatcher
+{
+  nsIAndroidEventDispatcher getDispatcherByName(in string name);
+};
diff --git a/widget/android/nsLookAndFeel.cpp b/widget/android/nsLookAndFeel.cpp
new file mode 100644
index 0000000000..02919e0dbf
--- /dev/null
+++ b/widget/android/nsLookAndFeel.cpp
@@ -0,0 +1,460 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsStyleConsts.h"
+#include "nsXULAppAPI.h"
+#include "nsLookAndFeel.h"
+#include "Theme.h"
+#include "gfxFont.h"
+#include "gfxFontConstants.h"
+#include "mozilla/FontPropertyTypes.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/java/GeckoAppShellWrappers.h"
+#include "mozilla/java/GeckoRuntimeWrappers.h"
+#include "mozilla/java/GeckoSystemStateListenerWrappers.h"
+#include "ThemeColors.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+static const char16_t UNICODE_BULLET = 0x2022;
+
+nsLookAndFeel::nsLookAndFeel() = default;
+
+nsLookAndFeel::~nsLookAndFeel() = default;
+
+nsresult nsLookAndFeel::GetSystemColors() {
+  if (!jni::IsAvailable()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  auto arr = java::GeckoAppShell::GetSystemColors();
+  if (!arr) {
+    return NS_ERROR_FAILURE;
+  }
+
+  JNIEnv* const env = arr.Env();
+  uint32_t len = static_cast<uint32_t>(env->GetArrayLength(arr.Get()));
+  jint* elements = env->GetIntArrayElements(arr.Get(), 0);
+
+  uint32_t colorsCount = sizeof(AndroidSystemColors) / sizeof(nscolor);
+  if (len < colorsCount) colorsCount = len;
+
+  // Convert Android colors to nscolor by switching R and B in the ARGB 32 bit
+  // value
+  nscolor* colors = (nscolor*)&mSystemColors;
+
+  for (uint32_t i = 0; i < colorsCount; i++) {
+    uint32_t androidColor = static_cast<uint32_t>(elements[i]);
+    uint8_t r = (androidColor & 0x00ff0000) >> 16;
+    uint8_t b = (androidColor & 0x000000ff);
+    colors[i] = (androidColor & 0xff00ff00) | (b << 16) | r;
+  }
+
+  env->ReleaseIntArrayElements(arr.Get(), elements, 0);
+
+  return NS_OK;
+}
+
+void nsLookAndFeel::NativeInit() {
+  EnsureInitSystemColors();
+  EnsureInitShowPassword();
+  RecordTelemetry();
+}
+
+void nsLookAndFeel::RefreshImpl() {
+  mInitializedSystemColors = false;
+  mInitializedShowPassword = false;
+  nsXPLookAndFeel::RefreshImpl();
+}
+
+nsresult nsLookAndFeel::NativeGetColor(ColorID aID, ColorScheme aColorScheme,
+                                       nscolor& aColor) {
+  EnsureInitSystemColors();
+  if (!mInitializedSystemColors) {
+    // Failure to initialize colors is an error condition. Return black.
+    aColor = 0;
+    return NS_ERROR_FAILURE;
+  }
+
+  // Highlight/Highlighttext have native equivalents that we can map to (on
+  // Android) which should work fine, regardless of the color-scheme.
+  switch (aID) {
+    case ColorID::Highlight: {
+      // Matched to action_accent in java codebase. This works fine with both
+      // light and dark color scheme.
+      nscolor accent =
+          Color(ColorID::Accentcolor, aColorScheme, UseStandins::No);
+      aColor =
+          NS_RGBA(NS_GET_R(accent), NS_GET_G(accent), NS_GET_B(accent), 78);
+      return NS_OK;
+    }
+    case ColorID::Highlighttext:
+      // Selection background is transparent enough that any foreground color
+      // will do.
+      aColor = NS_SAME_AS_FOREGROUND_COLOR;
+      return NS_OK;
+    default:
+      break;
+  }
+
+  if (aColorScheme == ColorScheme::Dark) {
+    if (auto darkColor = GenericDarkColor(aID)) {
+      aColor = *darkColor;
+      return NS_OK;
+    }
+  }
+
+  // XXX we'll want to use context.obtainStyledAttributes on the java side to
+  // get all of these; see TextView.java for a good example.
+  auto UseNativeAccent = [this] {
+    return mSystemColors.colorAccent &&
+           StaticPrefs::widget_non_native_theme_use_theme_accent();
+  };
+
+  switch (aID) {
+      // These colors don't seem to be used for anything anymore in Mozilla
+      // The CSS2 colors below are used.
+    case ColorID::ThemedScrollbarThumbInactive:
+    case ColorID::ThemedScrollbarThumb:
+      // We don't need to care about the Active and Hover colors because Android
+      // scrollbars can't be hovered (they always have pointer-events: none).
+      aColor = NS_RGBA(119, 119, 119, 102);
+      break;
+
+    case ColorID::IMESelectedRawTextBackground:
+    case ColorID::IMESelectedConvertedTextBackground:
+      aColor = mSystemColors.textColorHighlight;
+      break;
+    case ColorID::IMESelectedRawTextForeground:
+    case ColorID::IMESelectedConvertedTextForeground:
+      aColor = mSystemColors.textColorPrimaryInverse;
+      break;
+    case ColorID::IMERawInputBackground:
+    case ColorID::IMEConvertedTextBackground:
+      aColor = NS_TRANSPARENT;
+      break;
+    case ColorID::IMERawInputForeground:
+    case ColorID::IMEConvertedTextForeground:
+    case ColorID::IMERawInputUnderline:
+    case ColorID::IMEConvertedTextUnderline:
+      aColor = NS_SAME_AS_FOREGROUND_COLOR;
+      break;
+    case ColorID::IMESelectedRawTextUnderline:
+    case ColorID::IMESelectedConvertedTextUnderline:
+      aColor = NS_TRANSPARENT;
+      break;
+
+      // css2  http://www.w3.org/TR/REC-CSS2/ui.html#system-colors
+    case ColorID::Activeborder:     // active window border
+    case ColorID::Appworkspace:     // MDI background color
+    case ColorID::Activecaption:    // active window caption background
+    case ColorID::Background:       // desktop background
+    case ColorID::Inactiveborder:   // inactive window border
+    case ColorID::Inactivecaption:  // inactive window caption
+    case ColorID::Scrollbar:        // scrollbar gray area
+      aColor = mSystemColors.colorBackground;
+      break;
+    case ColorID::Graytext:  // disabled text in windows, menus, etc.
+      aColor = NS_RGB(0xb1, 0xa5, 0x98);
+      break;
+    // FIXME: -moz-cellhighlight should show some kind of unfocused state.
+    case ColorID::MozCellhighlight:
+    case ColorID::Selecteditem:
+    case ColorID::Accentcolor:
+      aColor = UseNativeAccent() ? mSystemColors.colorAccent
+                                 : GetStandinForNativeColor(
+                                       ColorID::Accentcolor, aColorScheme);
+      break;
+    case ColorID::MozCellhighlighttext:
+    case ColorID::Selecteditemtext:
+    case ColorID::Accentcolortext:
+      aColor = UseNativeAccent() ? ThemeColors::ComputeCustomAccentForeground(
+                                       mSystemColors.colorAccent)
+                                 : GetStandinForNativeColor(
+                                       ColorID::Accentcolortext, aColorScheme);
+      break;
+    case ColorID::Fieldtext:
+      aColor = NS_RGB(0x1a, 0x1a, 0x1a);
+      break;
+    case ColorID::Inactivecaptiontext:
+      // text in inactive window caption
+      aColor = mSystemColors.textColorTertiary;
+      break;
+    case ColorID::Infobackground:
+      aColor = NS_RGB(0xf5, 0xf5, 0xb5);
+      break;
+    case ColorID::Infotext:
+    case ColorID::Threeddarkshadow:  // 3-D shadow outer edge color
+      aColor = NS_RGB(0x00, 0x00, 0x00);
+      break;
+    case ColorID::Menu:
+      aColor = NS_RGB(0xf7, 0xf5, 0xf3);
+      break;
+
+    case ColorID::Buttonface:
+    case ColorID::MozButtondisabledface:
+    case ColorID::Threedface:
+    case ColorID::Threedlightshadow:
+    case ColorID::Buttonborder:
+    case ColorID::MozDisabledfield:
+      aColor = NS_RGB(0xec, 0xe7, 0xe2);
+      break;
+
+    case ColorID::Buttonhighlight:
+    case ColorID::Field:
+    case ColorID::Threedhighlight:
+    case ColorID::MozCombobox:
+    case ColorID::MozEventreerow:
+      aColor = NS_RGB(0xff, 0xff, 0xff);
+      break;
+
+    case ColorID::Buttonshadow:
+    case ColorID::Threedshadow:
+      aColor = NS_RGB(0xae, 0xa1, 0x94);
+      break;
+
+    case ColorID::MozDialog:
+    case ColorID::Window:
+    case ColorID::Windowframe:
+      aColor = NS_RGB(0xef, 0xeb, 0xe7);
+      break;
+    case ColorID::Buttontext:
+    case ColorID::Captiontext:
+    case ColorID::Menutext:
+    case ColorID::MozButtonhovertext:
+    case ColorID::MozDialogtext:
+    case ColorID::MozComboboxtext:
+    case ColorID::Windowtext:
+    case ColorID::MozColheadertext:
+    case ColorID::MozColheaderhovertext:
+      aColor = NS_RGB(0x10, 0x10, 0x10);
+      break;
+    case ColorID::MozButtonhoverface:
+    case ColorID::MozButtonactiveface:
+      aColor = NS_RGB(0xf3, 0xf0, 0xed);
+      break;
+    case ColorID::MozMenuhover:
+      aColor = NS_RGB(0xee, 0xee, 0xee);
+      break;
+    case ColorID::MozMenubarhovertext:
+    case ColorID::MozMenuhovertext:
+      aColor = NS_RGB(0x77, 0x77, 0x77);
+      break;
+    case ColorID::MozOddtreerow:
+      aColor = NS_TRANSPARENT;
+      break;
+    case ColorID::MozNativehyperlinktext:
+      aColor = NS_RGB(0, 0, 0xee);
+      break;
+    case ColorID::Marktext:
+    case ColorID::Mark:
+    case ColorID::SpellCheckerUnderline:
+      aColor = GetStandinForNativeColor(aID, aColorScheme);
+      break;
+    default:
+      /* default color is BLACK */
+      aColor = 0;
+      return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+nsresult nsLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
+  nsresult rv = NS_OK;
+
+  switch (aID) {
+    case IntID::ScrollbarFadeBeginDelay:
+      aResult = 450;
+      break;
+
+    case IntID::ScrollbarFadeDuration:
+      aResult = 300;
+      break;
+
+    case IntID::ScrollButtonLeftMouseButtonAction:
+      aResult = 0;
+      break;
+
+    case IntID::ScrollButtonMiddleMouseButtonAction:
+    case IntID::ScrollButtonRightMouseButtonAction:
+      aResult = 3;
+      break;
+
+    case IntID::CaretBlinkTime:
+      aResult = 500;
+      break;
+
+    case IntID::CaretBlinkCount:
+      aResult = 10;
+      break;
+
+    case IntID::CaretWidth:
+      aResult = 1;
+      break;
+
+    case IntID::ShowCaretDuringSelection:
+      aResult = 0;
+      break;
+
+    case IntID::SelectTextfieldsOnKeyFocus:
+      // Select textfield content when focused by kbd
+      // used by EventStateManager::sTextfieldSelectModel
+      aResult = 1;
+      break;
+
+    case IntID::SubmenuDelay:
+      aResult = 200;
+      break;
+
+    case IntID::TooltipDelay:
+      aResult = 500;
+      break;
+
+    case IntID::MenusCanOverlapOSBar:
+      // we want XUL popups to be able to overlap the task bar.
+      aResult = 1;
+      break;
+
+    case IntID::ScrollArrowStyle:
+      aResult = eScrollArrowStyle_Single;
+      break;
+
+    case IntID::UseOverlayScrollbars:
+      aResult = 1;
+      break;
+
+    case IntID::SpellCheckerUnderlineStyle:
+      aResult = int32_t(StyleTextDecorationStyle::Wavy);
+      break;
+
+    case IntID::ScrollbarButtonAutoRepeatBehavior:
+      aResult = 0;
+      break;
+
+    case IntID::ContextMenuOffsetVertical:
+    case IntID::ContextMenuOffsetHorizontal:
+      aResult = 2;
+      break;
+
+    case IntID::PrefersReducedMotion:
+      aResult = java::GeckoSystemStateListener::PrefersReducedMotion();
+      break;
+
+    case IntID::UseAccessibilityTheme:
+    // If high contrast is enabled, enable prefers-reduced-transparency media
+    // query as well as there is no dedicated option.
+    case IntID::PrefersReducedTransparency:
+      aResult = java::GeckoSystemStateListener::PrefersContrast();
+      break;
+
+    case IntID::InvertedColors:
+      aResult = java::GeckoSystemStateListener::IsInvertedColors();
+      break;
+
+    case IntID::PrimaryPointerCapabilities:
+      aResult = java::GeckoAppShell::GetAllPointerCapabilities();
+
+      // We cannot assume what is primary device, so we use Blink's way for web
+      // compatibility (https://crbug.com/136119#c6). If having coarse
+      // capability in any devices, return it.
+      if (aResult & static_cast<int32_t>(PointerCapabilities::Coarse)) {
+        aResult = static_cast<int32_t>(PointerCapabilities::Coarse);
+      }
+      break;
+
+    case IntID::AllPointerCapabilities:
+      aResult = java::GeckoAppShell::GetAllPointerCapabilities();
+      break;
+
+    case IntID::SystemUsesDarkTheme: {
+      java::GeckoRuntime::LocalRef runtime = java::GeckoRuntime::GetInstance();
+      aResult = runtime && runtime->UsesDarkTheme();
+      break;
+    }
+
+    case IntID::DragThresholdX:
+    case IntID::DragThresholdY:
+      // Threshold where a tap becomes a drag, in 1/240" reference pixels.
+      aResult = 25;
+      break;
+
+    case IntID::TouchDeviceSupportPresent:
+      // Touch support is always enabled on android.
+      aResult = 1;
+      break;
+
+    default:
+      aResult = 0;
+      rv = NS_ERROR_FAILURE;
+  }
+
+  return rv;
+}
+
+nsresult nsLookAndFeel::NativeGetFloat(FloatID aID, float& aResult) {
+  nsresult rv = NS_OK;
+
+  switch (aID) {
+    case FloatID::IMEUnderlineRelativeSize:
+      aResult = 1.0f;
+      break;
+    case FloatID::SpellCheckerUnderlineRelativeSize:
+      aResult = 1.0f;
+      break;
+    case FloatID::TextScaleFactor: {
+      java::GeckoRuntime::LocalRef runtime = java::GeckoRuntime::GetInstance();
+      aResult = runtime ? runtime->TextScaleFactor() : 1.0f;
+      break;
+    }
+    default:
+      aResult = -1.0;
+      rv = NS_ERROR_FAILURE;
+      break;
+  }
+  return rv;
+}
+
+bool nsLookAndFeel::NativeGetFont(FontID aID, nsString& aFontName,
+                                  gfxFontStyle& aFontStyle) {
+  aFontName.AssignLiteral("Roboto");
+  aFontStyle.style = FontSlantStyle::NORMAL;
+  aFontStyle.weight = FontWeight::NORMAL;
+  aFontStyle.stretch = FontStretch::NORMAL;
+  aFontStyle.size = 9.0 * 96.0f / 72.0f;
+  aFontStyle.systemFont = true;
+  return true;
+}
+
+bool nsLookAndFeel::GetEchoPasswordImpl() {
+  EnsureInitShowPassword();
+  return mShowPassword;
+}
+
+uint32_t nsLookAndFeel::GetPasswordMaskDelayImpl() {
+  // This value is hard-coded in Android OS's PasswordTransformationMethod.java
+  return 1500;
+}
+
+char16_t nsLookAndFeel::GetPasswordCharacterImpl() {
+  // This value is hard-coded in Android OS's PasswordTransformationMethod.java
+  return UNICODE_BULLET;
+}
+
+void nsLookAndFeel::EnsureInitSystemColors() {
+  if (!mInitializedSystemColors) {
+    mInitializedSystemColors = NS_SUCCEEDED(GetSystemColors());
+  }
+}
+
+void nsLookAndFeel::EnsureInitShowPassword() {
+  if (!mInitializedShowPassword && jni::IsAvailable()) {
+    mShowPassword = java::GeckoAppShell::GetShowPasswordSetting();
+    mInitializedShowPassword = true;
+  }
+}
diff --git a/widget/android/nsLookAndFeel.h b/widget/android/nsLookAndFeel.h
new file mode 100644
index 0000000000..128b871a08
--- /dev/null
+++ b/widget/android/nsLookAndFeel.h
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef __nsLookAndFeel
+#define __nsLookAndFeel
+
+#include "nsXPLookAndFeel.h"
+
+namespace mozilla {
+// The order and number of the members in this structure must correspond
+// to the attrsAppearance array in GeckoAppShell.getSystemColors()
+struct AndroidSystemColors {
+  nscolor textColorPrimary;
+  nscolor textColorPrimaryInverse;
+  nscolor textColorSecondary;
+  nscolor textColorSecondaryInverse;
+  nscolor textColorTertiary;
+  nscolor textColorTertiaryInverse;
+  nscolor textColorHighlight;
+  nscolor colorForeground;
+  nscolor colorBackground;
+  nscolor panelColorForeground;
+  nscolor panelColorBackground;
+  nscolor colorAccent;
+};
+}  // namespace mozilla
+
+class nsLookAndFeel final : public nsXPLookAndFeel {
+ public:
+  explicit nsLookAndFeel();
+  virtual ~nsLookAndFeel();
+
+  void NativeInit() final;
+  virtual void RefreshImpl() override;
+  nsresult NativeGetInt(IntID, int32_t& aResult) override;
+  nsresult NativeGetFloat(FloatID, float& aResult) override;
+  nsresult NativeGetColor(ColorID, ColorScheme, nscolor& aResult) override;
+  bool NativeGetFont(FontID aID, nsString& aName,
+                     gfxFontStyle& aStyle) override;
+  bool GetEchoPasswordImpl() override;
+  uint32_t GetPasswordMaskDelayImpl() override;
+  char16_t GetPasswordCharacterImpl() override;
+
+ protected:
+  bool mInitializedSystemColors = false;
+  mozilla::AndroidSystemColors mSystemColors;
+  bool mInitializedShowPassword = false;
+  bool mShowPassword = false;
+
+  nsresult GetSystemColors();
+
+  void EnsureInitSystemColors();
+  void EnsureInitShowPassword();
+};
+
+#endif
diff --git a/widget/android/nsPrintSettingsServiceAndroid.cpp b/widget/android/nsPrintSettingsServiceAndroid.cpp
new file mode 100644
index 0000000000..67f978c6e3
--- /dev/null
+++ b/widget/android/nsPrintSettingsServiceAndroid.cpp
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "nsPrintSettingsServiceAndroid.h"
+
+#include "nsPrintSettingsImpl.h"
+
+class nsPrintSettingsAndroid : public nsPrintSettings {
+ public:
+  nsPrintSettingsAndroid() {
+    // The aim here is to set up the objects enough that silent printing works
+    SetOutputFormat(nsIPrintSettings::kOutputFormatPDF);
+    SetPrinterName(u"PDF printer"_ns);
+  }
+};
+
+nsresult nsPrintSettingsServiceAndroid::_CreatePrintSettings(
+    nsIPrintSettings** _retval) {
+  nsPrintSettings* printSettings = new nsPrintSettingsAndroid();
+  NS_ENSURE_TRUE(printSettings, NS_ERROR_OUT_OF_MEMORY);
+  NS_ADDREF(*_retval = printSettings);
+  (void)InitPrintSettingsFromPrefs(*_retval, false,
+                                   nsIPrintSettings::kInitSaveAll);
+  return NS_OK;
+}
+
+already_AddRefed<nsIPrintSettings> CreatePlatformPrintSettings(
+    const mozilla::PrintSettingsInitializer& aSettings) {
+  RefPtr<nsPrintSettings> settings = new nsPrintSettingsAndroid();
+  settings->InitWithInitializer(aSettings);
+  return settings.forget();
+}
diff --git a/widget/android/nsPrintSettingsServiceAndroid.h b/widget/android/nsPrintSettingsServiceAndroid.h
new file mode 100644
index 0000000000..28710feb54
--- /dev/null
+++ b/widget/android/nsPrintSettingsServiceAndroid.h
@@ -0,0 +1,18 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef nsPrintSettingsServiceAndroid_h
+#define nsPrintSettingsServiceAndroid_h
+
+#include "nsPrintSettingsService.h"
+#include "nsIPrintSettings.h"
+
+class nsPrintSettingsServiceAndroid final : public nsPrintSettingsService {
+ public:
+  nsPrintSettingsServiceAndroid() {}
+
+  nsresult _CreatePrintSettings(nsIPrintSettings** _retval) override;
+};
+
+#endif  // nsPrintSettingsServiceAndroid_h
diff --git a/widget/android/nsUserIdleServiceAndroid.cpp b/widget/android/nsUserIdleServiceAndroid.cpp
new file mode 100644
index 0000000000..670aebe82e
--- /dev/null
+++ b/widget/android/nsUserIdleServiceAndroid.cpp
@@ -0,0 +1,12 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsUserIdleServiceAndroid.h"
+
+bool nsUserIdleServiceAndroid::PollIdleTime(uint32_t* aIdleTime) {
+  return false;
+}
diff --git a/widget/android/nsUserIdleServiceAndroid.h b/widget/android/nsUserIdleServiceAndroid.h
new file mode 100644
index 0000000000..4e089b3db6
--- /dev/null
+++ b/widget/android/nsUserIdleServiceAndroid.h
@@ -0,0 +1,40 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsUserIdleServiceAndroid_h__
+#define nsUserIdleServiceAndroid_h__
+
+#include "nsUserIdleService.h"
+#include "mozilla/AppShutdown.h"
+
+class nsUserIdleServiceAndroid : public nsUserIdleService {
+ public:
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(nsUserIdleServiceAndroid,
+                                       nsUserIdleService)
+
+  bool PollIdleTime(uint32_t* aIdleTime) override;
+
+  static already_AddRefed<nsUserIdleServiceAndroid> GetInstance() {
+    RefPtr<nsUserIdleService> idleService = nsUserIdleService::GetInstance();
+    if (!idleService) {
+      // Avoid late instantiation or resurrection during shutdown.
+      if (mozilla::AppShutdown::IsInOrBeyond(
+              mozilla::ShutdownPhase::AppShutdownConfirmed)) {
+        return nullptr;
+      }
+      idleService = new nsUserIdleServiceAndroid();
+    }
+
+    return idleService.forget().downcast<nsUserIdleServiceAndroid>();
+  }
+
+ protected:
+  nsUserIdleServiceAndroid() {}
+  virtual ~nsUserIdleServiceAndroid() {}
+};
+
+#endif  // nsUserIdleServiceAndroid_h__
diff --git a/widget/android/nsWidgetFactory.cpp b/widget/android/nsWidgetFactory.cpp
new file mode 100644
index 0000000000..00ebd20dd9
--- /dev/null
+++ b/widget/android/nsWidgetFactory.cpp
@@ -0,0 +1,21 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/WidgetUtils.h"
+
+#include "nsAppShell.h"
+
+#include "nsLookAndFeel.h"
+#include "nsAppShellSingleton.h"
+
+nsresult nsWidgetAndroidModuleCtor() { return nsAppShellInit(); }
+
+void nsWidgetAndroidModuleDtor() {
+  // Shutdown all XP level widget classes.
+  mozilla::widget::WidgetUtils::Shutdown();
+
+  nsLookAndFeel::Shutdown();
+  nsAppShellShutdown();
+}
diff --git a/widget/android/nsWidgetFactory.h b/widget/android/nsWidgetFactory.h
new file mode 100644
index 0000000000..934d75d8be
--- /dev/null
+++ b/widget/android/nsWidgetFactory.h
@@ -0,0 +1,21 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_android_nsWidgetFactory_h
+#define widget_android_nsWidgetFactory_h
+
+#include "nscore.h"
+#include "nsID.h"
+
+class nsISupports;
+
+nsresult nsAppShellConstructor(const nsIID& iid, void** result);
+
+nsresult nsWidgetAndroidModuleCtor();
+void nsWidgetAndroidModuleDtor();
+
+#endif  // defined widget_android_nsWidgetFactory_h
diff --git a/widget/android/nsWindow.cpp b/widget/android/nsWindow.cpp
new file mode 100644
index 0000000000..e9756c3f92
--- /dev/null
+++ b/widget/android/nsWindow.cpp
@@ -0,0 +1,3381 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 4; indent-tabs-mode: nil; -*-
+ * vim: set sw=2 ts=4 expandtab:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <algorithm>
+#include <atomic>
+#include <android/log.h>
+#include <android/native_window.h>
+#include <android/native_window_jni.h>
+#include <math.h>
+#include <queue>
+#include <type_traits>
+#include <unistd.h>
+
+#include "AndroidBridge.h"
+#include "AndroidBridgeUtilities.h"
+#include "AndroidCompositorWidget.h"
+#include "AndroidContentController.h"
+#include "AndroidDragEvent.h"
+#include "AndroidUiThread.h"
+#include "AndroidView.h"
+#include "AndroidWidgetUtils.h"
+#include "gfxContext.h"
+#include "GeckoEditableSupport.h"
+#include "GeckoViewOutputStream.h"
+#include "GeckoViewSupport.h"
+#include "GLContext.h"
+#include "GLContextProvider.h"
+#include "JavaBuiltins.h"
+#include "JavaExceptions.h"
+#include "KeyEvent.h"
+#include "MotionEvent.h"
+#include "ScopedGLHelpers.h"
+#include "ScreenHelperAndroid.h"
+#include "TouchResampler.h"
+#include "WidgetUtils.h"
+#include "WindowRenderer.h"
+
+#include "mozilla/EventForwards.h"
+#include "nsAppShell.h"
+#include "nsContentUtils.h"
+#include "nsFocusManager.h"
+#include "nsGkAtoms.h"
+#include "nsGfxCIID.h"
+#include "nsIDocShellTreeOwner.h"
+#include "nsLayoutUtils.h"
+#include "nsNetUtil.h"
+#include "nsPrintfCString.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "nsThreadUtils.h"
+#include "nsUserIdleService.h"
+#include "nsViewManager.h"
+#include "nsWidgetsCID.h"
+#include "nsWindow.h"
+
+#include "nsIWidgetListener.h"
+#include "nsIWindowWatcher.h"
+#include "nsIAppWindow.h"
+#include "nsIPrintSettings.h"
+#include "nsIPrintSettingsService.h"
+
+#include "mozilla/Logging.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_android.h"
+#include "mozilla/StaticPrefs_ui.h"
+#include "mozilla/TouchEvents.h"
+#include "mozilla/WeakPtr.h"
+#include "mozilla/WheelHandlingHelper.h"  // for WheelDeltaAdjustmentStrategy
+#include "mozilla/a11y/SessionAccessibility.h"
+#include "mozilla/dom/BrowsingContext.h"
+#include "mozilla/dom/BrowserHost.h"
+#include "mozilla/dom/CanonicalBrowsingContext.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/MouseEventBinding.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/DataSurfaceHelpers.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/gfx/Swizzle.h"
+#include "mozilla/gfx/Types.h"
+#include "mozilla/ipc/Shmem.h"
+#include "mozilla/java/EventDispatcherWrappers.h"
+#include "mozilla/java/GeckoAppShellWrappers.h"
+#include "mozilla/java/GeckoEditableChildWrappers.h"
+#include "mozilla/java/GeckoResultWrappers.h"
+#include "mozilla/java/GeckoSessionNatives.h"
+#include "mozilla/java/GeckoSystemStateListenerWrappers.h"
+#include "mozilla/java/PanZoomControllerNatives.h"
+#include "mozilla/java/SessionAccessibilityWrappers.h"
+#include "mozilla/java/SurfaceControlManagerWrappers.h"
+#include "mozilla/jni/NativesInlines.h"
+#include "mozilla/layers/APZEventState.h"
+#include "mozilla/layers/APZInputBridge.h"
+#include "mozilla/layers/APZThreadUtils.h"
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "mozilla/layers/CompositorOGL.h"
+#include "mozilla/layers/CompositorSession.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/layers/UiCompositorControllerChild.h"
+#include "mozilla/layers/IAPZCTreeManager.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/widget/AndroidVsync.h"
+#include "mozilla/widget/Screen.h"
+
+#define GVS_LOG(...) MOZ_LOG(sGVSupportLog, LogLevel::Warning, (__VA_ARGS__))
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::layers;
+using namespace mozilla::widget;
+using namespace mozilla::ipc;
+
+using mozilla::dom::ContentChild;
+using mozilla::dom::ContentParent;
+using mozilla::gfx::DataSourceSurface;
+using mozilla::gfx::IntSize;
+using mozilla::gfx::Matrix;
+using mozilla::gfx::SurfaceFormat;
+using mozilla::java::GeckoSession;
+using mozilla::java::sdk::IllegalStateException;
+using GeckoPrintException = GeckoSession::GeckoPrintException;
+static mozilla::LazyLogModule sGVSupportLog("GeckoViewSupport");
+
+// All the toplevel windows that have been created; these are in
+// stacking order, so the window at gTopLevelWindows[0] is the topmost
+// one.
+static nsTArray<nsWindow*> gTopLevelWindows;
+
+static bool sFailedToCreateGLContext = false;
+
+// Multitouch swipe thresholds in inches
+static const double SWIPE_MAX_PINCH_DELTA_INCHES = 0.4;
+static const double SWIPE_MIN_DISTANCE_INCHES = 0.6;
+
+static const double kTouchResampleVsyncAdjustMs = 5.0;
+
+static const int32_t INPUT_RESULT_UNHANDLED =
+    java::PanZoomController::INPUT_RESULT_UNHANDLED;
+static const int32_t INPUT_RESULT_HANDLED =
+    java::PanZoomController::INPUT_RESULT_HANDLED;
+static const int32_t INPUT_RESULT_HANDLED_CONTENT =
+    java::PanZoomController::INPUT_RESULT_HANDLED_CONTENT;
+static const int32_t INPUT_RESULT_IGNORED =
+    java::PanZoomController::INPUT_RESULT_IGNORED;
+
+static const nsCString::size_type MAX_TOPLEVEL_DATA_URI_LEN = 2 * 1024 * 1024;
+
+// Unique ID given to each widget, to identify it for the
+// CompositorSurfaceManager.
+static std::atomic<int32_t> sWidgetId{0};
+
+namespace {
+template <class Instance, class Impl>
+std::enable_if_t<jni::detail::NativePtrPicker<Impl>::value ==
+                     jni::detail::NativePtrType::REFPTR,
+                 void>
+CallAttachNative(Instance aInstance, Impl* aImpl) {
+  Impl::AttachNative(aInstance, RefPtr<Impl>(aImpl).get());
+}
+
+template <class Instance, class Impl>
+std::enable_if_t<jni::detail::NativePtrPicker<Impl>::value ==
+                     jni::detail::NativePtrType::OWNING,
+                 void>
+CallAttachNative(Instance aInstance, Impl* aImpl) {
+  Impl::AttachNative(aInstance, UniquePtr<Impl>(aImpl));
+}
+
+template <class Lambda>
+bool DispatchToUiThread(const char* aName, Lambda&& aLambda) {
+  if (RefPtr<nsThread> uiThread = GetAndroidUiThread()) {
+    uiThread->Dispatch(NS_NewRunnableFunction(aName, std::move(aLambda)));
+    return true;
+  }
+  return false;
+}
+}  // namespace
+
+namespace mozilla {
+namespace widget {
+
+using WindowPtr = jni::NativeWeakPtr<GeckoViewSupport>;
+
+/**
+ * PanZoomController handles its native calls on the UI thread, so make
+ * it separate from GeckoViewSupport.
+ */
+class NPZCSupport final
+    : public java::PanZoomController::NativeProvider::Natives<NPZCSupport> {
+  WindowPtr mWindow;
+  java::PanZoomController::NativeProvider::WeakRef mNPZC;
+
+  // Stores the returnResult of each pending motion event between
+  // HandleMotionEvent and FinishHandlingMotionEvent.
+  std::queue<std::pair<uint64_t, java::GeckoResult::GlobalRef>>
+      mPendingMotionEventReturnResults;
+
+  RefPtr<AndroidVsync> mAndroidVsync;
+  TouchResampler mTouchResampler;
+  int mPreviousButtons = 0;
+  bool mListeningToVsync = false;
+
+  // Only true if mAndroidVsync is non-null and the resampling pref is set.
+  bool mTouchResamplingEnabled = false;
+
+  template <typename Lambda>
+  class InputEvent final : public nsAppShell::Event {
+    java::PanZoomController::NativeProvider::GlobalRef mNPZC;
+    Lambda mLambda;
+
+   public:
+    InputEvent(const NPZCSupport* aNPZCSupport, Lambda&& aLambda)
+        : mNPZC(aNPZCSupport->mNPZC), mLambda(std::move(aLambda)) {}
+
+    void Run() override {
+      MOZ_ASSERT(NS_IsMainThread());
+
+      JNIEnv* const env = jni::GetGeckoThreadEnv();
+      const auto npzcSupportWeak = GetNative(
+          java::PanZoomController::NativeProvider::LocalRef(env, mNPZC));
+      if (!npzcSupportWeak) {
+        // We already shut down.
+        env->ExceptionClear();
+        return;
+      }
+
+      auto acc = npzcSupportWeak->Access();
+      if (!acc) {
+        // We already shut down.
+        env->ExceptionClear();
+        return;
+      }
+
+      auto win = acc->mWindow.Access();
+      if (!win) {
+        // We already shut down.
+        env->ExceptionClear();
+        return;
+      }
+
+      nsWindow* const window = win->GetNsWindow();
+      if (!window) {
+        // We already shut down.
+        env->ExceptionClear();
+        return;
+      }
+
+      window->UserActivity();
+      return mLambda(window);
+    }
+
+    bool IsUIEvent() const override { return true; }
+  };
+
+  class MOZ_HEAP_CLASS Observer final : public AndroidVsync::Observer {
+   public:
+    static Observer* Create(jni::NativeWeakPtr<NPZCSupport>&& aNPZCSupport) {
+      return new Observer(std::move(aNPZCSupport));
+    }
+
+   private:
+    // Private constructor, part of a strategy to make sure
+    // we're only able to create these on the heap.
+    explicit Observer(jni::NativeWeakPtr<NPZCSupport>&& aNPZCSupport)
+        : mNPZCSupport(std::move(aNPZCSupport)) {}
+
+    void OnVsync(const TimeStamp& aTimeStamp) override {
+      auto accessor = mNPZCSupport.Access();
+
+      if (!accessor) {
+        return;
+      }
+
+      accessor->mTouchResampler.NotifyFrame(
+          aTimeStamp -
+          TimeDuration::FromMilliseconds(kTouchResampleVsyncAdjustMs));
+      accessor->ConsumeMotionEventsFromResampler();
+    }
+
+    void Dispose() override { delete this; }
+
+    jni::NativeWeakPtr<NPZCSupport> mNPZCSupport;
+  };
+
+  Observer* mObserver = nullptr;
+
+  template <typename Lambda>
+  void PostInputEvent(Lambda&& aLambda) {
+    // Use priority queue for input events.
+    nsAppShell::PostEvent(
+        MakeUnique<InputEvent<Lambda>>(this, std::move(aLambda)));
+  }
+
+ public:
+  typedef java::PanZoomController::NativeProvider::Natives<NPZCSupport> Base;
+
+  NPZCSupport(WindowPtr aWindow,
+              const java::PanZoomController::NativeProvider::LocalRef& aNPZC)
+      : mWindow(aWindow), mNPZC(aNPZC) {
+#if defined(DEBUG)
+    auto win(mWindow.Access());
+    MOZ_ASSERT(!!win);
+#endif  // defined(DEBUG)
+
+    mAndroidVsync = AndroidVsync::GetInstance();
+  }
+
+  ~NPZCSupport() {
+    if (mListeningToVsync) {
+      MOZ_RELEASE_ASSERT(mAndroidVsync);
+      mAndroidVsync->UnregisterObserver(mObserver, AndroidVsync::INPUT);
+      mListeningToVsync = false;
+    }
+  }
+
+  using Base::AttachNative;
+  using Base::DisposeNative;
+
+  void OnWeakNonIntrusiveDetach(already_AddRefed<Runnable> aDisposer) {
+    RefPtr<Runnable> disposer = aDisposer;
+    // There are several considerations when shutting down NPZC. 1) The
+    // Gecko thread may destroy NPZC at any time when nsWindow closes. 2)
+    // There may be pending events on the Gecko thread when NPZC is
+    // destroyed. 3) mWindow may not be available when the pending event
+    // runs. 4) The UI thread may destroy NPZC at any time when GeckoView
+    // is destroyed. 5) The UI thread may destroy NPZC at the same time as
+    // Gecko thread trying to destroy NPZC. 6) There may be pending calls
+    // on the UI thread when NPZC is destroyed. 7) mWindow may have been
+    // cleared on the Gecko thread when the pending call happens on the UI
+    // thread.
+    //
+    // 1) happens through OnWeakNonIntrusiveDetach, which first notifies the UI
+    // thread through Destroy; Destroy then calls DisposeNative, which
+    // finally disposes the native instance back on the Gecko thread. Using
+    // Destroy to indirectly call DisposeNative here also solves 5), by
+    // making everything go through the UI thread, avoiding contention.
+    //
+    // 2) and 3) are solved by clearing mWindow, which signals to the
+    // pending event that we had shut down. In that case the event bails
+    // and does not touch mWindow.
+    //
+    // 4) happens through DisposeNative directly.
+    //
+    // 6) is solved by keeping a destroyed flag in the Java NPZC instance,
+    // and only make a pending call if the destroyed flag is not set.
+    //
+    // 7) is solved by taking a lock whenever mWindow is modified on the
+    // Gecko thread or accessed on the UI thread. That way, we don't
+    // release mWindow until the UI thread is done using it, thus avoiding
+    // the race condition.
+
+    if (RefPtr<nsThread> uiThread = GetAndroidUiThread()) {
+      auto npzc = java::PanZoomController::NativeProvider::GlobalRef(mNPZC);
+      if (!npzc) {
+        return;
+      }
+
+      uiThread->Dispatch(
+          NS_NewRunnableFunction("NPZCSupport::OnWeakNonIntrusiveDetach",
+                                 [npzc, disposer = std::move(disposer)] {
+                                   npzc->SetAttached(false);
+                                   disposer->Run();
+                                 }));
+    }
+  }
+
+  const java::PanZoomController::NativeProvider::Ref& GetJavaNPZC() const {
+    return mNPZC;
+  }
+
+ public:
+  void SetIsLongpressEnabled(bool aIsLongpressEnabled) {
+    RefPtr<IAPZCTreeManager> controller;
+
+    if (auto window = mWindow.Access()) {
+      nsWindow* gkWindow = window->GetNsWindow();
+      if (gkWindow) {
+        controller = gkWindow->mAPZC;
+      }
+    }
+
+    if (controller) {
+      controller->SetLongTapEnabled(aIsLongpressEnabled);
+    }
+  }
+
+  int32_t HandleScrollEvent(int64_t aTime, int32_t aMetaState, float aX,
+                            float aY, float aHScroll, float aVScroll) {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+
+    RefPtr<IAPZCTreeManager> controller;
+
+    if (auto window = mWindow.Access()) {
+      nsWindow* gkWindow = window->GetNsWindow();
+      if (gkWindow) {
+        controller = gkWindow->mAPZC;
+      }
+    }
+
+    if (!controller) {
+      return INPUT_RESULT_UNHANDLED;
+    }
+
+    ScreenPoint origin = ScreenPoint(aX, aY);
+
+    if (StaticPrefs::ui_scrolling_negate_wheel_scroll()) {
+      aHScroll = -aHScroll;
+      aVScroll = -aVScroll;
+    }
+
+    ScrollWheelInput input(
+        nsWindow::GetEventTimeStamp(aTime), nsWindow::GetModifiers(aMetaState),
+        ScrollWheelInput::SCROLLMODE_SMOOTH,
+        ScrollWheelInput::SCROLLDELTA_PIXEL, origin, aHScroll, aVScroll, false,
+        // XXX Do we need to support auto-dir scrolling
+        // for Android widgets with a wheel device?
+        // Currently, I just leave it unimplemented. If
+        // we need to implement it, what's the extra work
+        // to do?
+        WheelDeltaAdjustmentStrategy::eNone);
+
+    APZEventResult result = controller->InputBridge()->ReceiveInputEvent(input);
+    if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+      return INPUT_RESULT_IGNORED;
+    }
+
+    PostInputEvent([input = std::move(input), result](nsWindow* window) {
+      WidgetWheelEvent wheelEvent = input.ToWidgetEvent(window);
+      window->ProcessUntransformedAPZEvent(&wheelEvent, result);
+    });
+
+    switch (result.GetStatus()) {
+      case nsEventStatus_eIgnore:
+        return INPUT_RESULT_UNHANDLED;
+      case nsEventStatus_eConsumeDoDefault:
+        return result.GetHandledResult()->IsHandledByRoot()
+                   ? INPUT_RESULT_HANDLED
+                   : INPUT_RESULT_HANDLED_CONTENT;
+      default:
+        MOZ_ASSERT_UNREACHABLE("Unexpected nsEventStatus");
+        return INPUT_RESULT_UNHANDLED;
+    }
+  }
+
+ private:
+  static MouseInput::ButtonType GetButtonType(int button) {
+    MouseInput::ButtonType result = MouseInput::NONE;
+
+    switch (button) {
+      case java::sdk::MotionEvent::BUTTON_PRIMARY:
+        result = MouseInput::PRIMARY_BUTTON;
+        break;
+      case java::sdk::MotionEvent::BUTTON_SECONDARY:
+        result = MouseInput::SECONDARY_BUTTON;
+        break;
+      case java::sdk::MotionEvent::BUTTON_TERTIARY:
+        result = MouseInput::MIDDLE_BUTTON;
+        break;
+      default:
+        break;
+    }
+
+    return result;
+  }
+
+  static int16_t ConvertButtons(int buttons) {
+    int16_t result = 0;
+
+    if (buttons & java::sdk::MotionEvent::BUTTON_PRIMARY) {
+      result |= MouseButtonsFlag::ePrimaryFlag;
+    }
+    if (buttons & java::sdk::MotionEvent::BUTTON_SECONDARY) {
+      result |= MouseButtonsFlag::eSecondaryFlag;
+    }
+    if (buttons & java::sdk::MotionEvent::BUTTON_TERTIARY) {
+      result |= MouseButtonsFlag::eMiddleFlag;
+    }
+    if (buttons & java::sdk::MotionEvent::BUTTON_BACK) {
+      result |= MouseButtonsFlag::e4thFlag;
+    }
+    if (buttons & java::sdk::MotionEvent::BUTTON_FORWARD) {
+      result |= MouseButtonsFlag::e5thFlag;
+    }
+
+    return result;
+  }
+
+  static int32_t ConvertAPZHandledPlace(APZHandledPlace aHandledPlace) {
+    switch (aHandledPlace) {
+      case APZHandledPlace::Unhandled:
+        return INPUT_RESULT_UNHANDLED;
+      case APZHandledPlace::HandledByRoot:
+        return INPUT_RESULT_HANDLED;
+      case APZHandledPlace::HandledByContent:
+        return INPUT_RESULT_HANDLED_CONTENT;
+      case APZHandledPlace::Invalid:
+        MOZ_ASSERT_UNREACHABLE("The handled result should NOT be Invalid");
+        return INPUT_RESULT_UNHANDLED;
+    }
+    MOZ_ASSERT_UNREACHABLE("Unknown handled result");
+    return INPUT_RESULT_UNHANDLED;
+  }
+
+  static int32_t ConvertSideBits(SideBits aSideBits) {
+    int32_t ret = java::PanZoomController::SCROLLABLE_FLAG_NONE;
+    if (aSideBits & SideBits::eTop) {
+      ret |= java::PanZoomController::SCROLLABLE_FLAG_TOP;
+    }
+    if (aSideBits & SideBits::eRight) {
+      ret |= java::PanZoomController::SCROLLABLE_FLAG_RIGHT;
+    }
+    if (aSideBits & SideBits::eBottom) {
+      ret |= java::PanZoomController::SCROLLABLE_FLAG_BOTTOM;
+    }
+    if (aSideBits & SideBits::eLeft) {
+      ret |= java::PanZoomController::SCROLLABLE_FLAG_LEFT;
+    }
+    return ret;
+  }
+
+  static int32_t ConvertScrollDirections(
+      layers::ScrollDirections aScrollDirections) {
+    int32_t ret = java::PanZoomController::OVERSCROLL_FLAG_NONE;
+    if (aScrollDirections.contains(layers::HorizontalScrollDirection)) {
+      ret |= java::PanZoomController::OVERSCROLL_FLAG_HORIZONTAL;
+    }
+    if (aScrollDirections.contains(layers::VerticalScrollDirection)) {
+      ret |= java::PanZoomController::OVERSCROLL_FLAG_VERTICAL;
+    }
+    return ret;
+  }
+
+  static java::PanZoomController::InputResultDetail::LocalRef
+  ConvertAPZHandledResult(const APZHandledResult& aHandledResult) {
+    return java::PanZoomController::InputResultDetail::New(
+        ConvertAPZHandledPlace(aHandledResult.mPlace),
+        ConvertSideBits(aHandledResult.mScrollableDirections),
+        ConvertScrollDirections(aHandledResult.mOverscrollDirections));
+  }
+
+ public:
+  int32_t HandleMouseEvent(int32_t aAction, int64_t aTime, int32_t aMetaState,
+                           float aX, float aY, int buttons) {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+
+    RefPtr<IAPZCTreeManager> controller;
+
+    if (auto window = mWindow.Access()) {
+      nsWindow* gkWindow = window->GetNsWindow();
+      if (gkWindow) {
+        controller = gkWindow->mAPZC;
+      }
+    }
+
+    if (!controller) {
+      return INPUT_RESULT_UNHANDLED;
+    }
+
+    MouseInput::MouseType mouseType = MouseInput::MOUSE_NONE;
+    MouseInput::ButtonType buttonType = MouseInput::NONE;
+    switch (aAction) {
+      case java::sdk::MotionEvent::ACTION_DOWN:
+        mouseType = MouseInput::MOUSE_DOWN;
+        buttonType = GetButtonType(buttons ^ mPreviousButtons);
+        mPreviousButtons = buttons;
+        break;
+      case java::sdk::MotionEvent::ACTION_UP:
+        mouseType = MouseInput::MOUSE_UP;
+        buttonType = GetButtonType(buttons ^ mPreviousButtons);
+        mPreviousButtons = buttons;
+        break;
+      case java::sdk::MotionEvent::ACTION_MOVE:
+        mouseType = MouseInput::MOUSE_MOVE;
+        break;
+      case java::sdk::MotionEvent::ACTION_HOVER_MOVE:
+        mouseType = MouseInput::MOUSE_MOVE;
+        break;
+      case java::sdk::MotionEvent::ACTION_HOVER_ENTER:
+        mouseType = MouseInput::MOUSE_WIDGET_ENTER;
+        break;
+      case java::sdk::MotionEvent::ACTION_HOVER_EXIT:
+        mouseType = MouseInput::MOUSE_WIDGET_EXIT;
+        break;
+      default:
+        break;
+    }
+
+    if (mouseType == MouseInput::MOUSE_NONE) {
+      return INPUT_RESULT_UNHANDLED;
+    }
+
+    ScreenPoint origin = ScreenPoint(aX, aY);
+
+    MouseInput input(
+        mouseType, buttonType, MouseEvent_Binding::MOZ_SOURCE_MOUSE,
+        ConvertButtons(buttons), origin, nsWindow::GetEventTimeStamp(aTime),
+        nsWindow::GetModifiers(aMetaState));
+
+    APZEventResult result = controller->InputBridge()->ReceiveInputEvent(input);
+    if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+      return INPUT_RESULT_IGNORED;
+    }
+
+    PostInputEvent([input = std::move(input), result](nsWindow* window) {
+      WidgetMouseEvent mouseEvent = input.ToWidgetEvent(window);
+      window->ProcessUntransformedAPZEvent(&mouseEvent, result);
+    });
+
+    switch (result.GetStatus()) {
+      case nsEventStatus_eIgnore:
+        return INPUT_RESULT_UNHANDLED;
+      case nsEventStatus_eConsumeDoDefault:
+        return result.GetHandledResult()->IsHandledByRoot()
+                   ? INPUT_RESULT_HANDLED
+                   : INPUT_RESULT_HANDLED_CONTENT;
+      default:
+        MOZ_ASSERT_UNREACHABLE("Unexpected nsEventStatus");
+        return INPUT_RESULT_UNHANDLED;
+    }
+  }
+
+  // Convert MotionEvent touch radius and orientation into the format required
+  // by w3c touchevents.
+  // toolMajor and toolMinor span a rectangle that's oriented as per
+  // aOrientation, centered around the touch point.
+  static std::pair<float, ScreenSize> ConvertOrientationAndRadius(
+      float aOrientation, float aToolMajor, float aToolMinor) {
+    float angle = aOrientation * 180.0f / M_PI;
+    // w3c touchevents spec does not allow orientations == 90
+    // this shifts it to -90, which will be shifted to zero below
+    if (angle >= 90.0) {
+      angle -= 180.0f;
+    }
+
+    // w3c touchevent radii are given with an orientation between 0 and
+    // 90. The radii are found by removing the orientation and
+    // measuring the x and y radii of the resulting ellipse. For
+    // Android orientations >= 0 and < 90, use the y radius as the
+    // major radius, and x as the minor radius. However, for an
+    // orientation < 0, we have to shift the orientation by adding 90,
+    // and reverse which radius is major and minor.
+    ScreenSize radius;
+    if (angle < 0.0f) {
+      angle += 90.0f;
+      radius =
+          ScreenSize(int32_t(aToolMajor / 2.0f), int32_t(aToolMinor / 2.0f));
+    } else {
+      radius =
+          ScreenSize(int32_t(aToolMinor / 2.0f), int32_t(aToolMajor / 2.0f));
+    }
+
+    return std::make_pair(angle, radius);
+  }
+
+  void HandleMotionEvent(
+      const java::PanZoomController::NativeProvider::LocalRef& aInstance,
+      jni::Object::Param aEventData, float aScreenX, float aScreenY,
+      jni::Object::Param aResult) {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+
+    auto returnResult = java::GeckoResult::Ref::From(aResult);
+    auto eventData =
+        java::PanZoomController::MotionEventData::Ref::From(aEventData);
+    nsTArray<int32_t> pointerId(eventData->PointerId()->GetElements());
+    size_t pointerCount = pointerId.Length();
+    MultiTouchInput::MultiTouchType type;
+    size_t startIndex = 0;
+    size_t endIndex = pointerCount;
+
+    switch (eventData->Action()) {
+      case java::sdk::MotionEvent::ACTION_DOWN:
+      case java::sdk::MotionEvent::ACTION_POINTER_DOWN:
+        type = MultiTouchInput::MULTITOUCH_START;
+        break;
+      case java::sdk::MotionEvent::ACTION_MOVE:
+        type = MultiTouchInput::MULTITOUCH_MOVE;
+        break;
+      case java::sdk::MotionEvent::ACTION_UP:
+      case java::sdk::MotionEvent::ACTION_POINTER_UP:
+        // for pointer-up events we only want the data from
+        // the one pointer that went up
+        type = MultiTouchInput::MULTITOUCH_END;
+        startIndex = eventData->ActionIndex();
+        endIndex = startIndex + 1;
+        break;
+      case java::sdk::MotionEvent::ACTION_OUTSIDE:
+      case java::sdk::MotionEvent::ACTION_CANCEL:
+        type = MultiTouchInput::MULTITOUCH_CANCEL;
+        break;
+      default:
+        if (returnResult) {
+          returnResult->Complete(
+              java::sdk::Integer::ValueOf(INPUT_RESULT_UNHANDLED));
+        }
+        return;
+    }
+
+    MultiTouchInput input(type, eventData->Time(),
+                          nsWindow::GetEventTimeStamp(eventData->Time()), 0);
+    input.modifiers = nsWindow::GetModifiers(eventData->MetaState());
+    input.mTouches.SetCapacity(endIndex - startIndex);
+    input.mScreenOffset =
+        ExternalIntPoint(int32_t(floorf(aScreenX)), int32_t(floorf(aScreenY)));
+
+    size_t historySize = eventData->HistorySize();
+    nsTArray<int64_t> historicalTime(
+        eventData->HistoricalTime()->GetElements());
+    MOZ_RELEASE_ASSERT(historicalTime.Length() == historySize);
+
+    // Each of these is |historySize| sets of |pointerCount| values.
+    size_t historicalDataCount = historySize * pointerCount;
+    nsTArray<float> historicalX(eventData->HistoricalX()->GetElements());
+    nsTArray<float> historicalY(eventData->HistoricalY()->GetElements());
+    nsTArray<float> historicalOrientation(
+        eventData->HistoricalOrientation()->GetElements());
+    nsTArray<float> historicalPressure(
+        eventData->HistoricalPressure()->GetElements());
+    nsTArray<float> historicalToolMajor(
+        eventData->HistoricalToolMajor()->GetElements());
+    nsTArray<float> historicalToolMinor(
+        eventData->HistoricalToolMinor()->GetElements());
+
+    MOZ_RELEASE_ASSERT(historicalX.Length() == historicalDataCount);
+    MOZ_RELEASE_ASSERT(historicalY.Length() == historicalDataCount);
+    MOZ_RELEASE_ASSERT(historicalOrientation.Length() == historicalDataCount);
+    MOZ_RELEASE_ASSERT(historicalPressure.Length() == historicalDataCount);
+    MOZ_RELEASE_ASSERT(historicalToolMajor.Length() == historicalDataCount);
+    MOZ_RELEASE_ASSERT(historicalToolMinor.Length() == historicalDataCount);
+
+    // Each of these is |pointerCount| values.
+    nsTArray<float> x(eventData->X()->GetElements());
+    nsTArray<float> y(eventData->Y()->GetElements());
+    nsTArray<float> orientation(eventData->Orientation()->GetElements());
+    nsTArray<float> pressure(eventData->Pressure()->GetElements());
+    nsTArray<float> toolMajor(eventData->ToolMajor()->GetElements());
+    nsTArray<float> toolMinor(eventData->ToolMinor()->GetElements());
+
+    MOZ_ASSERT(x.Length() == pointerCount);
+    MOZ_ASSERT(y.Length() == pointerCount);
+    MOZ_ASSERT(orientation.Length() == pointerCount);
+    MOZ_ASSERT(pressure.Length() == pointerCount);
+    MOZ_ASSERT(toolMajor.Length() == pointerCount);
+    MOZ_ASSERT(toolMinor.Length() == pointerCount);
+
+    for (size_t i = startIndex; i < endIndex; i++) {
+      auto [orien, radius] = ConvertOrientationAndRadius(
+          orientation[i], toolMajor[i], toolMinor[i]);
+
+      ScreenIntPoint point(int32_t(floorf(x[i])), int32_t(floorf(y[i])));
+      SingleTouchData singleTouchData(pointerId[i], point, radius, orien,
+                                      pressure[i]);
+
+      for (size_t historyIndex = 0; historyIndex < historySize;
+           historyIndex++) {
+        size_t historicalI = historyIndex * pointerCount + i;
+        auto [historicalAngle, historicalRadius] = ConvertOrientationAndRadius(
+            historicalOrientation[historicalI],
+            historicalToolMajor[historicalI], historicalToolMinor[historicalI]);
+        ScreenIntPoint historicalPoint(
+            int32_t(floorf(historicalX[historicalI])),
+            int32_t(floorf(historicalY[historicalI])));
+        singleTouchData.mHistoricalData.AppendElement(
+            SingleTouchData::HistoricalTouchData{
+                nsWindow::GetEventTimeStamp(historicalTime[historyIndex]),
+                historicalPoint,
+                {},  // mLocalScreenPoint will be computed later by APZ
+                historicalRadius,
+                historicalAngle,
+                historicalPressure[historicalI]});
+      }
+
+      input.mTouches.AppendElement(singleTouchData);
+    }
+
+    if (mAndroidVsync &&
+        eventData->Action() == java::sdk::MotionEvent::ACTION_DOWN) {
+      // Query pref value at the beginning of a touch gesture so that we don't
+      // leave events stuck in the resampler after a pref flip.
+      mTouchResamplingEnabled = StaticPrefs::android_touch_resampling_enabled();
+    }
+
+    if (!mTouchResamplingEnabled) {
+      FinishHandlingMotionEvent(std::move(input),
+                                java::GeckoResult::LocalRef(returnResult));
+      return;
+    }
+
+    uint64_t eventId = mTouchResampler.ProcessEvent(std::move(input));
+    mPendingMotionEventReturnResults.push(
+        {eventId, java::GeckoResult::GlobalRef(returnResult)});
+
+    RegisterOrUnregisterForVsync(mTouchResampler.InTouchingState());
+    ConsumeMotionEventsFromResampler();
+  }
+
+  void RegisterOrUnregisterForVsync(bool aNeedVsync) {
+    MOZ_RELEASE_ASSERT(mAndroidVsync);
+    if (aNeedVsync && !mListeningToVsync) {
+      MOZ_ASSERT(!mObserver);
+      auto win = mWindow.Access();
+      if (!win) {
+        return;
+      }
+      RefPtr<nsWindow> gkWindow = win->GetNsWindow();
+      if (!gkWindow) {
+        return;
+      }
+      MutexAutoLock lock(gkWindow->GetDestroyMutex());
+      if (gkWindow->Destroyed()) {
+        return;
+      }
+      jni::NativeWeakPtr<NPZCSupport> weakPtrToThis =
+          gkWindow->GetNPZCSupportWeakPtr();
+      mObserver = Observer::Create(std::move(weakPtrToThis));
+      mAndroidVsync->RegisterObserver(mObserver, AndroidVsync::INPUT);
+    } else if (!aNeedVsync && mListeningToVsync) {
+      mAndroidVsync->UnregisterObserver(mObserver, AndroidVsync::INPUT);
+      mObserver = nullptr;
+    }
+    mListeningToVsync = aNeedVsync;
+  }
+
+  void HandleDragEvent(int32_t aAction, int64_t aTime, float aX, float aY,
+                       jni::Object::Param aDropData) {
+    // APZ handles some drag event type on APZ thread, but it cannot handle all
+    // types.
+    MOZ_ASSERT(NS_IsMainThread());
+
+    if (auto window = mWindow.Access()) {
+      if (nsWindow* gkWindow = window->GetNsWindow()) {
+        gkWindow->OnDragEvent(aAction, aTime, aX, aY, aDropData);
+      }
+    }
+  }
+
+  void ConsumeMotionEventsFromResampler() {
+    auto outgoing = mTouchResampler.ConsumeOutgoingEvents();
+    while (!outgoing.empty()) {
+      auto outgoingEvent = std::move(outgoing.front());
+      outgoing.pop();
+      java::GeckoResult::GlobalRef returnResult;
+      if (outgoingEvent.mEventId) {
+        // Look up the GeckoResult for this event.
+        // The outgoing events from the resampler are in the same order as the
+        // original events, and no event IDs are skipped.
+        MOZ_RELEASE_ASSERT(!mPendingMotionEventReturnResults.empty());
+        auto pair = mPendingMotionEventReturnResults.front();
+        mPendingMotionEventReturnResults.pop();
+        MOZ_RELEASE_ASSERT(pair.first == *outgoingEvent.mEventId);
+        returnResult = pair.second;
+      }
+      FinishHandlingMotionEvent(std::move(outgoingEvent.mEvent),
+                                java::GeckoResult::LocalRef(returnResult));
+    }
+  }
+
+  void FinishHandlingMotionEvent(MultiTouchInput&& aInput,
+                                 java::GeckoResult::LocalRef&& aReturnResult) {
+    RefPtr<IAPZCTreeManager> controller;
+
+    if (auto window = mWindow.Access()) {
+      nsWindow* gkWindow = window->GetNsWindow();
+      if (gkWindow) {
+        controller = gkWindow->mAPZC;
+      }
+    }
+
+    if (!controller) {
+      if (aReturnResult) {
+        aReturnResult->Complete(java::PanZoomController::InputResultDetail::New(
+            INPUT_RESULT_UNHANDLED,
+            java::PanZoomController::SCROLLABLE_FLAG_NONE,
+            java::PanZoomController::OVERSCROLL_FLAG_NONE));
+      }
+      return;
+    }
+
+    APZInputBridge::InputBlockCallback callback;
+    if (aReturnResult) {
+      callback = [aReturnResult = java::GeckoResult::GlobalRef(aReturnResult)](
+                     uint64_t aInputBlockId,
+                     const APZHandledResult& aHandledResult) {
+        aReturnResult->Complete(ConvertAPZHandledResult(aHandledResult));
+      };
+    }
+    APZEventResult result = controller->InputBridge()->ReceiveInputEvent(
+        aInput, std::move(callback));
+
+    if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+      if (aReturnResult) {
+        if (result.GetHandledResult() != Nothing()) {
+          aReturnResult->Complete(
+              ConvertAPZHandledResult(result.GetHandledResult().value()));
+        } else {
+          MOZ_ASSERT_UNREACHABLE(
+              "nsEventStatus_eConsumeNoDefault should involve a valid "
+              "APZHandledResult");
+          aReturnResult->Complete(
+              java::PanZoomController::InputResultDetail::New(
+                  INPUT_RESULT_IGNORED,
+                  java::PanZoomController::SCROLLABLE_FLAG_NONE,
+                  java::PanZoomController::OVERSCROLL_FLAG_NONE));
+        }
+      }
+      return;
+    }
+
+    // Dispatch APZ input event on Gecko thread.
+    PostInputEvent([input = std::move(aInput), result](nsWindow* window) {
+      WidgetTouchEvent touchEvent = input.ToWidgetEvent(window);
+      window->ProcessUntransformedAPZEvent(&touchEvent, result);
+      window->DispatchHitTest(touchEvent);
+    });
+
+    if (aReturnResult && result.GetHandledResult() != Nothing()) {
+      MOZ_ASSERT(result.GetStatus() == nsEventStatus_eConsumeDoDefault ||
+                 result.GetStatus() == nsEventStatus_eIgnore);
+      aReturnResult->Complete(
+          ConvertAPZHandledResult(result.GetHandledResult().value()));
+    }
+  }
+};
+
+NS_IMPL_ISUPPORTS(AndroidView, nsIAndroidEventDispatcher, nsIAndroidView)
+
+nsresult AndroidView::GetInitData(JSContext* aCx,
+                                  JS::MutableHandle<JS::Value> aOut) {
+  if (!mInitData) {
+    aOut.setNull();
+    return NS_OK;
+  }
+
+  return widget::EventDispatcher::UnboxBundle(aCx, mInitData, aOut);
+}
+
+/**
+ * Compositor has some unique requirements for its native calls, so make it
+ * separate from GeckoViewSupport.
+ */
+class LayerViewSupport final
+    : public GeckoSession::Compositor::Natives<LayerViewSupport> {
+  WindowPtr mWindow;
+  GeckoSession::Compositor::WeakRef mCompositor;
+  Atomic<bool, ReleaseAcquire> mCompositorPaused;
+  java::sdk::Surface::GlobalRef mSurface;
+  java::sdk::SurfaceControl::GlobalRef mSurfaceControl;
+  int32_t mX;
+  int32_t mY;
+  int32_t mWidth;
+  int32_t mHeight;
+  // Used to communicate with the gecko compositor from the UI thread.
+  // Set in NotifyCompositorCreated and cleared in
+  // NotifyCompositorSessionLost.
+  RefPtr<UiCompositorControllerChild> mUiCompositorControllerChild;
+  // Whether we have requested a new Surface from the GeckoSession.
+  bool mRequestedNewSurface = false;
+
+  Maybe<uint32_t> mDefaultClearColor;
+
+  struct CaptureRequest {
+    explicit CaptureRequest() : mResult(nullptr) {}
+    explicit CaptureRequest(java::GeckoResult::GlobalRef aResult,
+                            java::sdk::Bitmap::GlobalRef aBitmap,
+                            const ScreenRect& aSource,
+                            const IntSize& aOutputSize)
+        : mResult(aResult),
+          mBitmap(aBitmap),
+          mSource(aSource),
+          mOutputSize(aOutputSize) {}
+
+    // where to send the pixels
+    java::GeckoResult::GlobalRef mResult;
+
+    // where to store the pixels
+    java::sdk::Bitmap::GlobalRef mBitmap;
+
+    ScreenRect mSource;
+
+    IntSize mOutputSize;
+  };
+  std::queue<CaptureRequest> mCapturePixelsResults;
+
+  // In order to use Event::HasSameTypeAs in PostTo(), we cannot make
+  // LayerViewEvent a template because each template instantiation is
+  // a different type. So implement LayerViewEvent as a ProxyEvent.
+  class LayerViewEvent final : public nsAppShell::ProxyEvent {
+    using Event = nsAppShell::Event;
+
+   public:
+    static UniquePtr<Event> MakeEvent(UniquePtr<Event>&& event) {
+      return MakeUnique<LayerViewEvent>(std::move(event));
+    }
+
+    explicit LayerViewEvent(UniquePtr<Event>&& event)
+        : nsAppShell::ProxyEvent(std::move(event)) {}
+
+    void PostTo(LinkedList<Event>& queue) override {
+      // Give priority to compositor events, but keep in order with
+      // existing compositor events.
+      nsAppShell::Event* event = queue.getFirst();
+      while (event && event->HasSameTypeAs(this)) {
+        event = event->getNext();
+      }
+      if (event) {
+        event->setPrevious(this);
+      } else {
+        queue.insertBack(this);
+      }
+    }
+  };
+
+ public:
+  typedef GeckoSession::Compositor::Natives<LayerViewSupport> Base;
+
+  LayerViewSupport(WindowPtr aWindow,
+                   const GeckoSession::Compositor::LocalRef& aInstance)
+      : mWindow(aWindow), mCompositor(aInstance), mCompositorPaused(true) {
+#if defined(DEBUG)
+    auto win(mWindow.Access());
+    MOZ_ASSERT(!!win);
+#endif  // defined(DEBUG)
+  }
+
+  ~LayerViewSupport() {}
+
+  using Base::AttachNative;
+  using Base::DisposeNative;
+
+  void OnWeakNonIntrusiveDetach(already_AddRefed<Runnable> aDisposer) {
+    RefPtr<Runnable> disposer = aDisposer;
+    if (RefPtr<nsThread> uiThread = GetAndroidUiThread()) {
+      GeckoSession::Compositor::GlobalRef compositor(mCompositor);
+      if (!compositor) {
+        return;
+      }
+
+      uiThread->Dispatch(NS_NewRunnableFunction(
+          "LayerViewSupport::OnWeakNonIntrusiveDetach",
+          [compositor, disposer = std::move(disposer),
+           results = &mCapturePixelsResults, window = mWindow]() mutable {
+            if (auto accWindow = window.Access()) {
+              while (!results->empty()) {
+                auto aResult =
+                    java::GeckoResult::LocalRef(results->front().mResult);
+                if (aResult) {
+                  aResult->CompleteExceptionally(
+                      java::sdk::IllegalStateException::New(
+                          "The compositor has detached from the session")
+                          .Cast<jni::Throwable>());
+                }
+                results->pop();
+              }
+            }
+
+            compositor->OnCompositorDetached();
+            disposer->Run();
+          }));
+    }
+  }
+
+  const GeckoSession::Compositor::Ref& GetJavaCompositor() const {
+    return mCompositor;
+  }
+
+  bool CompositorPaused() const { return mCompositorPaused; }
+
+  /// Called from the main thread whenever the compositor has been
+  /// (re)initialized.
+  void NotifyCompositorCreated(
+      RefPtr<UiCompositorControllerChild> aUiCompositorControllerChild) {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+    mUiCompositorControllerChild = aUiCompositorControllerChild;
+
+    if (mDefaultClearColor) {
+      mUiCompositorControllerChild->SetDefaultClearColor(*mDefaultClearColor);
+    }
+
+    if (!mCompositorPaused) {
+      // If we are using SurfaceControl but mSurface is null, that means the
+      // previous surface was destroyed along with the the previous
+      // compositor, and we need to create a new one.
+      if (mSurfaceControl && !mSurface) {
+        mSurface = java::SurfaceControlManager::GetInstance()->GetChildSurface(
+            mSurfaceControl, mWidth, mHeight);
+      }
+
+      if (auto window{mWindow.Access()}) {
+        nsWindow* gkWindow = window->GetNsWindow();
+        if (gkWindow) {
+          mUiCompositorControllerChild->OnCompositorSurfaceChanged(
+              gkWindow->mWidgetId, mSurface);
+        }
+      }
+
+      bool resumed = mUiCompositorControllerChild->ResumeAndResize(
+          mX, mY, mWidth, mHeight);
+      if (!resumed) {
+        gfxCriticalNote
+            << "Failed to resume compositor from NotifyCompositorCreated";
+        RequestNewSurface();
+      }
+    }
+  }
+
+  /// Called from the main thread whenever the compositor has been destroyed.
+  void NotifyCompositorSessionLost() {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+    mUiCompositorControllerChild = nullptr;
+
+    if (mSurfaceControl) {
+      // If we are using SurfaceControl then we must set the Surface to null
+      // here to ensure we create a new one when the new compositor is
+      // created.
+      mSurface = nullptr;
+    }
+
+    if (auto window = mWindow.Access()) {
+      while (!mCapturePixelsResults.empty()) {
+        auto result =
+            java::GeckoResult::LocalRef(mCapturePixelsResults.front().mResult);
+        if (result) {
+          result->CompleteExceptionally(
+              java::sdk::IllegalStateException::New(
+                  "Compositor session lost during screen pixels request")
+                  .Cast<jni::Throwable>());
+        }
+        mCapturePixelsResults.pop();
+      }
+    }
+  }
+
+  java::sdk::Surface::Param GetSurface() { return mSurface; }
+
+ private:
+  already_AddRefed<DataSourceSurface> FlipScreenPixels(
+      Shmem& aMem, const ScreenIntSize& aInSize, const ScreenRect& aInRegion,
+      const IntSize& aOutSize) {
+    RefPtr<gfx::DataSourceSurface> image =
+        gfx::Factory::CreateWrappingDataSourceSurface(
+            aMem.get<uint8_t>(),
+            StrideForFormatAndWidth(SurfaceFormat::B8G8R8A8, aInSize.width),
+            IntSize(aInSize.width, aInSize.height), SurfaceFormat::B8G8R8A8);
+    RefPtr<gfx::DrawTarget> drawTarget =
+        gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(
+            aOutSize, SurfaceFormat::B8G8R8A8);
+    if (!drawTarget) {
+      return nullptr;
+    }
+
+    drawTarget->SetTransform(Matrix::Scaling(1.0, -1.0) *
+                             Matrix::Translation(0, aOutSize.height));
+
+    gfx::Rect srcRect(aInRegion.x,
+                      (aInSize.height - aInRegion.height) - aInRegion.y,
+                      aInRegion.width, aInRegion.height);
+    gfx::Rect destRect(0, 0, aOutSize.width, aOutSize.height);
+    drawTarget->DrawSurface(image, destRect, srcRect);
+
+    RefPtr<gfx::SourceSurface> snapshot = drawTarget->Snapshot();
+    RefPtr<gfx::DataSourceSurface> data = snapshot->GetDataSurface();
+    return data.forget();
+  }
+
+  /**
+   * Compositor methods
+   */
+ public:
+  void AttachNPZC(jni::Object::Param aNPZC) {
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(aNPZC);
+
+    auto locked(mWindow.Access());
+    if (!locked) {
+      return;  // Already shut down.
+    }
+
+    nsWindow* gkWindow = locked->GetNsWindow();
+
+    // We can have this situation if we get two GeckoViewSupport::Transfer()
+    // called before the first AttachNPZC() gets here. Just detach the current
+    // instance since that's what happens in GeckoViewSupport::Transfer() as
+    // well.
+    gkWindow->mNPZCSupport.Detach();
+
+    auto npzc = java::PanZoomController::NativeProvider::LocalRef(
+        jni::GetGeckoThreadEnv(),
+        java::PanZoomController::NativeProvider::Ref::From(aNPZC));
+    gkWindow->mNPZCSupport =
+        jni::NativeWeakPtrHolder<NPZCSupport>::Attach(npzc, mWindow, npzc);
+
+    DispatchToUiThread(
+        "LayerViewSupport::AttachNPZC",
+        [npzc = java::PanZoomController::NativeProvider::GlobalRef(npzc)] {
+          npzc->SetAttached(true);
+        });
+  }
+
+  void OnBoundsChanged(int32_t aLeft, int32_t aTop, int32_t aWidth,
+                       int32_t aHeight) {
+    MOZ_ASSERT(NS_IsMainThread());
+    auto acc = mWindow.Access();
+    if (!acc) {
+      return;  // Already shut down.
+    }
+
+    nsWindow* gkWindow = acc->GetNsWindow();
+    if (!gkWindow) {
+      return;
+    }
+
+    gkWindow->Resize(aLeft, aTop, aWidth, aHeight, /* repaint */ false);
+  }
+
+  void NotifyMemoryPressure() {
+    MOZ_ASSERT(NS_IsMainThread());
+    auto acc = mWindow.Access();
+    if (!acc) {
+      return;  // Already shut down.
+    }
+
+    nsWindow* gkWindow = acc->GetNsWindow();
+    if (!gkWindow || !gkWindow->mCompositorBridgeChild) {
+      return;
+    }
+
+    gkWindow->mCompositorBridgeChild->SendNotifyMemoryPressure();
+  }
+
+  void SetDynamicToolbarMaxHeight(int32_t aHeight) {
+    MOZ_ASSERT(NS_IsMainThread());
+    auto acc = mWindow.Access();
+    if (!acc) {
+      return;  // Already shut down.
+    }
+
+    nsWindow* gkWindow = acc->GetNsWindow();
+    if (!gkWindow) {
+      return;
+    }
+
+    gkWindow->UpdateDynamicToolbarMaxHeight(ScreenIntCoord(aHeight));
+  }
+
+  void SyncPauseCompositor() {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+
+    mCompositorPaused = true;
+
+    if (mUiCompositorControllerChild) {
+      mUiCompositorControllerChild->Pause();
+
+      mSurface = nullptr;
+      mSurfaceControl = nullptr;
+      if (auto window = mWindow.Access()) {
+        nsWindow* gkWindow = window->GetNsWindow();
+        if (gkWindow) {
+          mUiCompositorControllerChild->OnCompositorSurfaceChanged(
+              gkWindow->mWidgetId, nullptr);
+        }
+      }
+    }
+
+    if (auto lock{mWindow.Access()}) {
+      while (!mCapturePixelsResults.empty()) {
+        auto result =
+            java::GeckoResult::LocalRef(mCapturePixelsResults.front().mResult);
+        if (result) {
+          result->CompleteExceptionally(
+              java::sdk::IllegalStateException::New(
+                  "The compositor has detached from the session")
+                  .Cast<jni::Throwable>());
+        }
+        mCapturePixelsResults.pop();
+      }
+    }
+  }
+
+  void SyncResumeCompositor() {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+
+    if (mUiCompositorControllerChild) {
+      mCompositorPaused = false;
+      bool resumed = mUiCompositorControllerChild->Resume();
+      if (!resumed) {
+        gfxCriticalNote
+            << "Failed to resume compositor from SyncResumeCompositor";
+        RequestNewSurface();
+      }
+    }
+  }
+
+  void SyncResumeResizeCompositor(
+      const GeckoSession::Compositor::LocalRef& aObj, int32_t aX, int32_t aY,
+      int32_t aWidth, int32_t aHeight, jni::Object::Param aSurface,
+      jni::Object::Param aSurfaceControl) {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+
+    mX = aX;
+    mY = aY;
+    mWidth = aWidth;
+    mHeight = aHeight;
+    if (StaticPrefs::widget_android_use_surfacecontrol_AtStartup()) {
+      mSurfaceControl =
+          java::sdk::SurfaceControl::GlobalRef::From(aSurfaceControl);
+    }
+    if (mSurfaceControl) {
+      // When using SurfaceControl, we create a child Surface to render in to
+      // rather than rendering directly in to the Surface provided by the
+      // application. This allows us to work around a bug on some versions of
+      // Android when recovering from a GPU process crash.
+      mSurface = java::SurfaceControlManager::GetInstance()->GetChildSurface(
+          mSurfaceControl, mWidth, mHeight);
+    } else {
+      mSurface = java::sdk::Surface::GlobalRef::From(aSurface);
+    }
+
+    if (mUiCompositorControllerChild) {
+      if (auto window = mWindow.Access()) {
+        nsWindow* gkWindow = window->GetNsWindow();
+        if (gkWindow) {
+          // Send new Surface to GPU process, if one exists.
+          mUiCompositorControllerChild->OnCompositorSurfaceChanged(
+              gkWindow->mWidgetId, mSurface);
+        }
+      }
+
+      bool resumed = mUiCompositorControllerChild->ResumeAndResize(
+          aX, aY, aWidth, aHeight);
+      if (!resumed) {
+        gfxCriticalNote
+            << "Failed to resume compositor from SyncResumeResizeCompositor";
+        // Only request a new Surface if this SyncResumeAndResize call is not
+        // response to a previous request, otherwise we will get stuck in an
+        // infinite loop.
+        if (!mRequestedNewSurface) {
+          RequestNewSurface();
+        }
+        return;
+      }
+    }
+
+    mRequestedNewSurface = false;
+
+    mCompositorPaused = false;
+
+    class OnResumedEvent : public nsAppShell::Event {
+      GeckoSession::Compositor::GlobalRef mCompositor;
+
+     public:
+      explicit OnResumedEvent(GeckoSession::Compositor::GlobalRef&& aCompositor)
+          : mCompositor(std::move(aCompositor)) {}
+
+      void Run() override {
+        MOZ_ASSERT(NS_IsMainThread());
+
+        JNIEnv* const env = jni::GetGeckoThreadEnv();
+        const auto lvsHolder =
+            GetNative(GeckoSession::Compositor::LocalRef(env, mCompositor));
+
+        if (!lvsHolder) {
+          env->ExceptionClear();
+          return;  // Already shut down.
+        }
+
+        auto lvs(lvsHolder->Access());
+        if (!lvs) {
+          env->ExceptionClear();
+          return;  // Already shut down.
+        }
+
+        auto win = lvs->mWindow.Access();
+        if (!win) {
+          env->ExceptionClear();
+          return;  // Already shut down.
+        }
+
+        // When we get here, the compositor has already been told to
+        // resume. This means it's now safe for layer updates to occur.
+        // Since we might have prevented one or more draw events from
+        // occurring while the compositor was paused, we need to
+        // schedule a draw event now.
+        if (!lvs->mCompositorPaused) {
+          nsWindow* const gkWindow = win->GetNsWindow();
+          if (gkWindow) {
+            gkWindow->RedrawAll();
+          }
+        }
+      }
+    };
+
+    // Use priority queue for timing-sensitive event.
+    nsAppShell::PostEvent(
+        MakeUnique<LayerViewEvent>(MakeUnique<OnResumedEvent>(aObj)));
+  }
+
+  void RequestNewSurface() {
+    if (const auto& compositor = GetJavaCompositor()) {
+      mRequestedNewSurface = true;
+      if (mSurfaceControl) {
+        java::SurfaceControlManager::GetInstance()->RemoveSurface(
+            mSurfaceControl);
+      }
+      compositor->RequestNewSurface();
+    }
+  }
+
+  mozilla::jni::Object::LocalRef GetMagnifiableSurface() {
+    return mozilla::jni::Object::LocalRef::From(GetSurface());
+  }
+
+  void SyncInvalidateAndScheduleComposite() {
+    if (!mUiCompositorControllerChild) {
+      return;
+    }
+
+    if (AndroidBridge::IsJavaUiThread()) {
+      mUiCompositorControllerChild->InvalidateAndRender();
+      return;
+    }
+
+    if (RefPtr<nsThread> uiThread = GetAndroidUiThread()) {
+      uiThread->Dispatch(NewRunnableMethod<>(
+                             "LayerViewSupport::InvalidateAndRender",
+                             mUiCompositorControllerChild,
+                             &UiCompositorControllerChild::InvalidateAndRender),
+                         nsIThread::DISPATCH_NORMAL);
+    }
+  }
+
+  void SetMaxToolbarHeight(int32_t aHeight) {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+
+    if (mUiCompositorControllerChild) {
+      mUiCompositorControllerChild->SetMaxToolbarHeight(aHeight);
+    }
+  }
+
+  void SetFixedBottomOffset(int32_t aOffset) {
+    if (auto acc{mWindow.Access()}) {
+      nsWindow* gkWindow = acc->GetNsWindow();
+      if (gkWindow) {
+        gkWindow->UpdateDynamicToolbarOffset(ScreenIntCoord(aOffset));
+      }
+    }
+
+    if (RefPtr<nsThread> uiThread = GetAndroidUiThread()) {
+      uiThread->Dispatch(NS_NewRunnableFunction(
+          "LayerViewSupport::SetFixedBottomOffset", [this, offset = aOffset] {
+            if (mUiCompositorControllerChild) {
+              mUiCompositorControllerChild->SetFixedBottomOffset(offset);
+            }
+          }));
+    }
+  }
+
+  void SendToolbarAnimatorMessage(int32_t aMessage) {
+    if (!mUiCompositorControllerChild) {
+      return;
+    }
+
+    if (AndroidBridge::IsJavaUiThread()) {
+      mUiCompositorControllerChild->ToolbarAnimatorMessageFromUI(aMessage);
+      return;
+    }
+
+    if (RefPtr<nsThread> uiThread = GetAndroidUiThread()) {
+      uiThread->Dispatch(
+          NewRunnableMethod<int32_t>(
+              "LayerViewSupport::ToolbarAnimatorMessageFromUI",
+              mUiCompositorControllerChild,
+              &UiCompositorControllerChild::ToolbarAnimatorMessageFromUI,
+              aMessage),
+          nsIThread::DISPATCH_NORMAL);
+    }
+  }
+
+  void RecvToolbarAnimatorMessage(int32_t aMessage) {
+    auto compositor = GeckoSession::Compositor::LocalRef(mCompositor);
+    if (compositor) {
+      compositor->RecvToolbarAnimatorMessage(aMessage);
+    }
+  }
+
+  void SetDefaultClearColor(int32_t aColor) {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+    mDefaultClearColor = Some((uint32_t)aColor);
+    if (mUiCompositorControllerChild) {
+      mUiCompositorControllerChild->SetDefaultClearColor((uint32_t)aColor);
+    }
+  }
+
+  void RequestScreenPixels(jni::Object::Param aResult,
+                           jni::Object::Param aTarget, int32_t aXOffset,
+                           int32_t aYOffset, int32_t aSrcWidth,
+                           int32_t aSrcHeight, int32_t aOutWidth,
+                           int32_t aOutHeight) {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+    auto result = java::GeckoResult::LocalRef(aResult);
+
+    if (!mUiCompositorControllerChild) {
+      if (result) {
+        if (auto window = mWindow.Access()) {
+          result->CompleteExceptionally(
+              java::sdk::IllegalStateException::New(
+                  "Compositor session lost prior to screen pixels request")
+                  .Cast<jni::Throwable>());
+        }
+      }
+      return;
+    }
+
+    int size = 0;
+    if (auto window = mWindow.Access()) {
+      mCapturePixelsResults.push(CaptureRequest(
+          java::GeckoResult::GlobalRef(result),
+          java::sdk::Bitmap::GlobalRef(java::sdk::Bitmap::LocalRef(aTarget)),
+          ScreenRect(aXOffset, aYOffset, aSrcWidth, aSrcHeight),
+          IntSize(aOutWidth, aOutHeight)));
+      size = mCapturePixelsResults.size();
+    }
+
+    if (size == 1) {
+      mUiCompositorControllerChild->RequestScreenPixels();
+    }
+  }
+
+  void RecvScreenPixels(Shmem&& aMem, const ScreenIntSize& aSize,
+                        bool aNeedsYFlip) {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+    CaptureRequest request;
+    java::GeckoResult::LocalRef result = nullptr;
+    java::sdk::Bitmap::LocalRef bitmap = nullptr;
+    if (auto window = mWindow.Access()) {
+      // The result might have been already rejected if the compositor was
+      // detached from the session
+      if (!mCapturePixelsResults.empty()) {
+        request = mCapturePixelsResults.front();
+        result = java::GeckoResult::LocalRef(request.mResult);
+        bitmap = java::sdk::Bitmap::LocalRef(request.mBitmap);
+        mCapturePixelsResults.pop();
+      }
+    }
+
+    if (result) {
+      if (bitmap) {
+        RefPtr<DataSourceSurface> surf;
+        if (aNeedsYFlip) {
+          surf = FlipScreenPixels(aMem, aSize, request.mSource,
+                                  request.mOutputSize);
+        } else {
+          surf = gfx::Factory::CreateWrappingDataSourceSurface(
+              aMem.get<uint8_t>(),
+              StrideForFormatAndWidth(SurfaceFormat::B8G8R8A8, aSize.width),
+              IntSize(aSize.width, aSize.height), SurfaceFormat::B8G8R8A8);
+        }
+        if (surf) {
+          DataSourceSurface::ScopedMap smap(surf, DataSourceSurface::READ);
+          auto pixels = mozilla::jni::ByteBuffer::New(
+              reinterpret_cast<int8_t*>(smap.GetData()),
+              smap.GetStride() * request.mOutputSize.height);
+          bitmap->CopyPixelsFromBuffer(pixels);
+          result->Complete(bitmap);
+        } else {
+          result->CompleteExceptionally(
+              java::sdk::IllegalStateException::New(
+                  "Failed to create flipped snapshot surface (probably out "
+                  "of memory)")
+                  .Cast<jni::Throwable>());
+        }
+      } else {
+        result->CompleteExceptionally(java::sdk::IllegalArgumentException::New(
+                                          "No target bitmap argument provided")
+                                          .Cast<jni::Throwable>());
+      }
+    }
+
+    // Pixels have been copied, so Dealloc Shmem
+    if (mUiCompositorControllerChild) {
+      mUiCompositorControllerChild->DeallocPixelBuffer(aMem);
+
+      if (auto window = mWindow.Access()) {
+        if (!mCapturePixelsResults.empty()) {
+          mUiCompositorControllerChild->RequestScreenPixels();
+        }
+      }
+    }
+  }
+
+  void EnableLayerUpdateNotifications(bool aEnable) {
+    MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+    if (mUiCompositorControllerChild) {
+      mUiCompositorControllerChild->EnableLayerUpdateNotifications(aEnable);
+    }
+  }
+
+  void OnSafeAreaInsetsChanged(int32_t aTop, int32_t aRight, int32_t aBottom,
+                               int32_t aLeft) {
+    MOZ_ASSERT(NS_IsMainThread());
+    auto win(mWindow.Access());
+    if (!win) {
+      return;  // Already shut down.
+    }
+
+    nsWindow* gkWindow = win->GetNsWindow();
+    if (!gkWindow) {
+      return;
+    }
+
+    ScreenIntMargin safeAreaInsets(aTop, aRight, aBottom, aLeft);
+    gkWindow->UpdateSafeAreaInsets(safeAreaInsets);
+  }
+};
+
+GeckoViewSupport::~GeckoViewSupport() {
+  if (mWindow) {
+    mWindow->DetachNatives();
+  }
+}
+
+/* static */
+void GeckoViewSupport::Open(
+    const jni::Class::LocalRef& aCls, GeckoSession::Window::Param aWindow,
+    jni::Object::Param aQueue, jni::Object::Param aCompositor,
+    jni::Object::Param aDispatcher, jni::Object::Param aSessionAccessibility,
+    jni::Object::Param aInitData, jni::String::Param aId,
+    jni::String::Param aChromeURI, bool aPrivateMode) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  AUTO_PROFILER_LABEL("mozilla::widget::GeckoViewSupport::Open", OTHER);
+
+  // We'll need gfxPlatform to be initialized to create a compositor later.
+  // Might as well do that now so that the GPU process launch can get a head
+  // start.
+  gfxPlatform::GetPlatform();
+
+  nsCOMPtr<nsIWindowWatcher> ww = do_GetService(NS_WINDOWWATCHER_CONTRACTID);
+  MOZ_RELEASE_ASSERT(ww);
+
+  nsAutoCString url;
+  if (aChromeURI) {
+    url = aChromeURI->ToCString();
+  } else {
+    nsresult rv = Preferences::GetCString("toolkit.defaultChromeURI", url);
+    if (NS_FAILED(rv)) {
+      url = "chrome://geckoview/content/geckoview.xhtml"_ns;
+    }
+  }
+
+  // Prepare an nsIAndroidView to pass as argument to the window.
+  RefPtr<AndroidView> androidView = new AndroidView();
+  androidView->mEventDispatcher->Attach(
+      java::EventDispatcher::Ref::From(aDispatcher), nullptr);
+  androidView->mInitData = java::GeckoBundle::Ref::From(aInitData);
+
+  nsAutoCString chromeFlags("chrome,dialog=0,remote,resizable,scrollbars");
+  if (aPrivateMode) {
+    chromeFlags += ",private";
+  }
+  nsCOMPtr<mozIDOMWindowProxy> domWindow;
+  ww->OpenWindow(nullptr, url, nsDependentCString(aId->ToCString().get()),
+                 chromeFlags, androidView, getter_AddRefs(domWindow));
+  MOZ_RELEASE_ASSERT(domWindow);
+
+  nsCOMPtr<nsPIDOMWindowOuter> pdomWindow = nsPIDOMWindowOuter::From(domWindow);
+  const RefPtr<nsWindow> window = nsWindow::From(pdomWindow);
+  MOZ_ASSERT(window);
+
+  // Attach a new GeckoView support object to the new window.
+  GeckoSession::Window::LocalRef sessionWindow(aCls.Env(), aWindow);
+  auto weakGeckoViewSupport =
+      jni::NativeWeakPtrHolder<GeckoViewSupport>::Attach(
+          sessionWindow, window, sessionWindow, pdomWindow);
+
+  window->mGeckoViewSupport = weakGeckoViewSupport;
+  window->mAndroidView = androidView;
+
+  // Attach other session support objects.
+  {  // Scope for gvsAccess
+    auto gvsAccess = weakGeckoViewSupport.Access();
+    MOZ_ASSERT(gvsAccess);
+
+    gvsAccess->Transfer(sessionWindow, aQueue, aCompositor, aDispatcher,
+                        aSessionAccessibility, aInitData);
+  }
+
+  if (window->mWidgetListener) {
+    nsCOMPtr<nsIAppWindow> appWindow(window->mWidgetListener->GetAppWindow());
+    if (appWindow) {
+      // Our window is not intrinsically sized, so tell AppWindow to
+      // not set a size for us.
+      appWindow->SetIntrinsicallySized(false);
+    }
+  }
+}
+
+void GeckoViewSupport::Close() {
+  if (mWindow) {
+    if (mWindow->mAndroidView) {
+      mWindow->mAndroidView->mEventDispatcher->Detach();
+    }
+    mWindow = nullptr;
+  }
+
+  if (!mDOMWindow) {
+    return;
+  }
+
+  mDOMWindow->ForceClose();
+  mDOMWindow = nullptr;
+  mGeckoViewWindow = nullptr;
+}
+
+void GeckoViewSupport::Transfer(const GeckoSession::Window::LocalRef& inst,
+                                jni::Object::Param aQueue,
+                                jni::Object::Param aCompositor,
+                                jni::Object::Param aDispatcher,
+                                jni::Object::Param aSessionAccessibility,
+                                jni::Object::Param aInitData) {
+  mWindow->mNPZCSupport.Detach();
+
+  auto compositor = GeckoSession::Compositor::LocalRef(
+      inst.Env(), GeckoSession::Compositor::Ref::From(aCompositor));
+
+  bool attachLvs;
+  {  // Scope for lvsAccess
+    auto lvsAccess{mWindow->mLayerViewSupport.Access()};
+    // If we do not yet have mLayerViewSupport, or if the compositor has
+    // changed, then we must attach a new one.
+    attachLvs = !lvsAccess || lvsAccess->GetJavaCompositor() != compositor;
+  }
+
+  if (attachLvs) {
+    mWindow->mLayerViewSupport =
+        jni::NativeWeakPtrHolder<LayerViewSupport>::Attach(
+            compositor, mWindow->mGeckoViewSupport, compositor);
+
+    if (RefPtr<UiCompositorControllerChild> uiCompositorController =
+            mWindow->GetUiCompositorControllerChild()) {
+      DispatchToUiThread(
+          "LayerViewSupport::NotifyCompositorCreated",
+          [lvs = mWindow->mLayerViewSupport, uiCompositorController] {
+            if (auto lvsAccess{lvs.Access()}) {
+              lvsAccess->NotifyCompositorCreated(uiCompositorController);
+            }
+          });
+    }
+  }
+
+  MOZ_ASSERT(mWindow->mAndroidView);
+  mWindow->mAndroidView->mEventDispatcher->Attach(
+      java::EventDispatcher::Ref::From(aDispatcher), mDOMWindow);
+
+  RefPtr<jni::DetachPromise> promise = mWindow->mSessionAccessibility.Detach();
+  if (aSessionAccessibility) {
+    // SessionAccessibility's JNI object isn't released immediately, it uses
+    // recycled object, we have to wait for released object completely.
+    auto sa = java::SessionAccessibility::NativeProvider::LocalRef(
+        aSessionAccessibility);
+    promise->Then(
+        GetMainThreadSerialEventTarget(),
+        "GeckoViewSupprt::Transfer::SessionAccessibility",
+        [inst = GeckoSession::Window::GlobalRef(inst),
+         sa = java::SessionAccessibility::NativeProvider::GlobalRef(sa),
+         window = mWindow, gvs = mWindow->mGeckoViewSupport](
+            const mozilla::jni::DetachPromise::ResolveOrRejectValue& aValue) {
+          MOZ_ASSERT(aValue.IsResolve());
+          if (window->Destroyed()) {
+            return;
+          }
+
+          MOZ_ASSERT(!window->mSessionAccessibility.IsAttached());
+          if (auto gvsAccess{gvs.Access()}) {
+            gvsAccess->AttachAccessibility(inst, sa);
+          }
+        });
+  }
+
+  if (mIsReady) {
+    // We're in a transfer; update init-data and notify JS code.
+    mWindow->mAndroidView->mInitData = java::GeckoBundle::Ref::From(aInitData);
+    OnReady(aQueue);
+    mWindow->mAndroidView->mEventDispatcher->Dispatch(
+        u"GeckoView:UpdateInitData");
+  }
+
+  DispatchToUiThread("GeckoViewSupport::Transfer",
+                     [compositor = GeckoSession::Compositor::GlobalRef(
+                          compositor)] { compositor->OnCompositorAttached(); });
+}
+
+void GeckoViewSupport::AttachEditable(
+    const GeckoSession::Window::LocalRef& inst,
+    jni::Object::Param aEditableParent) {
+  if (auto win{mWindow->mEditableSupport.Access()}) {
+    win->TransferParent(aEditableParent);
+  } else {
+    auto editableChild = java::GeckoEditableChild::New(aEditableParent,
+                                                       /* default */ true);
+    mWindow->mEditableSupport =
+        jni::NativeWeakPtrHolder<GeckoEditableSupport>::Attach(
+            editableChild, mWindow->mGeckoViewSupport, editableChild);
+  }
+
+  mWindow->mEditableParent = aEditableParent;
+}
+
+void GeckoViewSupport::AttachAccessibility(
+    const GeckoSession::Window::LocalRef& inst,
+    jni::Object::Param aSessionAccessibility) {
+  java::SessionAccessibility::NativeProvider::LocalRef sessionAccessibility(
+      inst.Env());
+  sessionAccessibility = java::SessionAccessibility::NativeProvider::Ref::From(
+      aSessionAccessibility);
+
+  mWindow->mSessionAccessibility =
+      jni::NativeWeakPtrHolder<a11y::SessionAccessibility>::Attach(
+          sessionAccessibility, mWindow->mGeckoViewSupport,
+          sessionAccessibility);
+}
+
+auto GeckoViewSupport::OnLoadRequest(mozilla::jni::String::Param aUri,
+                                     int32_t aWindowType, int32_t aFlags,
+                                     mozilla::jni::String::Param aTriggeringUri,
+                                     bool aHasUserGesture,
+                                     bool aIsTopLevel) const
+    -> java::GeckoResult::LocalRef {
+  GeckoSession::Window::LocalRef window(mGeckoViewWindow);
+  if (!window) {
+    return nullptr;
+  }
+  return window->OnLoadRequest(aUri, aWindowType, aFlags, aTriggeringUri,
+                               aHasUserGesture, aIsTopLevel);
+}
+
+void GeckoViewSupport::OnShowDynamicToolbar() const {
+  GeckoSession::Window::LocalRef window(mGeckoViewWindow);
+  if (!window) {
+    return;
+  }
+
+  window->OnShowDynamicToolbar();
+}
+
+void GeckoViewSupport::OnReady(jni::Object::Param aQueue) {
+  GeckoSession::Window::LocalRef window(mGeckoViewWindow);
+  if (!window) {
+    return;
+  }
+  window->OnReady(aQueue);
+  mIsReady = true;
+}
+
+void GeckoViewSupport::PassExternalResponse(
+    java::WebResponse::Param aResponse) {
+  GeckoSession::Window::LocalRef window(mGeckoViewWindow);
+  if (!window) {
+    return;
+  }
+
+  auto response = java::WebResponse::GlobalRef(aResponse);
+
+  DispatchToUiThread("GeckoViewSupport::PassExternalResponse",
+                     [window = java::GeckoSession::Window::GlobalRef(window),
+                      response] { window->PassExternalWebResponse(response); });
+}
+
+RefPtr<CanonicalBrowsingContext>
+GeckoViewSupport::GetContentCanonicalBrowsingContext() {
+  nsCOMPtr<nsIDocShellTreeOwner> treeOwner = mDOMWindow->GetTreeOwner();
+  if (!treeOwner) {
+    return nullptr;
+  }
+  RefPtr<BrowsingContext> bc;
+  nsresult rv = treeOwner->GetPrimaryContentBrowsingContext(getter_AddRefs(bc));
+  if (NS_WARN_IF(NS_FAILED(rv)) || !bc) {
+    return nullptr;
+  }
+  return bc->Canonical();
+}
+
+void GeckoViewSupport::CreatePdf(
+    jni::LocalRef<mozilla::java::GeckoResult> aGeckoResult,
+    RefPtr<dom::CanonicalBrowsingContext> aCbc) {
+  MOZ_ASSERT(NS_IsMainThread());
+  const auto pdfErrorMsg = "Could not save this page as PDF.";
+  auto stream = java::GeckoInputStream::New(nullptr);
+  RefPtr<GeckoViewOutputStream> streamListener =
+      new GeckoViewOutputStream(stream);
+
+  nsCOMPtr<nsIPrintSettingsService> printSettingsService =
+      do_GetService("@mozilla.org/gfx/printsettings-service;1");
+  if (!printSettingsService) {
+    aGeckoResult->CompleteExceptionally(
+        GeckoPrintException::New(
+            GeckoPrintException::ERROR_PRINT_SETTINGS_SERVICE_NOT_AVAILABLE)
+            .Cast<jni::Throwable>());
+    GVS_LOG("Could not create print settings service.");
+    return;
+  }
+
+  nsCOMPtr<nsIPrintSettings> printSettings;
+  nsresult rv = printSettingsService->CreateNewPrintSettings(
+      getter_AddRefs(printSettings));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    aGeckoResult->CompleteExceptionally(
+        GeckoPrintException::New(
+            GeckoPrintException::ERROR_UNABLE_TO_CREATE_PRINT_SETTINGS)
+            .Cast<jni::Throwable>());
+    GVS_LOG("Could not create print settings.");
+    return;
+  }
+
+  printSettings->SetPrinterName(u"Mozilla Save to PDF"_ns);
+  printSettings->SetOutputDestination(
+      nsIPrintSettings::kOutputDestinationStream);
+  printSettings->SetOutputFormat(nsIPrintSettings::kOutputFormatPDF);
+  printSettings->SetOutputStream(streamListener);
+  printSettings->SetPrintSilent(true);
+
+  RefPtr<CanonicalBrowsingContext::PrintPromise> print =
+      aCbc->Print(printSettings);
+
+  aGeckoResult->Complete(stream);
+  print->Then(
+      mozilla::GetCurrentSerialEventTarget(), __func__,
+      [result = java::GeckoResult::GlobalRef(aGeckoResult), stream,
+       pdfErrorMsg](
+          const CanonicalBrowsingContext::PrintPromise::ResolveOrRejectValue&
+              aValue) {
+        if (aValue.IsReject()) {
+          GVS_LOG("Could not print. %s", pdfErrorMsg);
+          stream->WriteError();
+        }
+      });
+}
+
+void GeckoViewSupport::PrintToPdf(
+    const java::GeckoSession::Window::LocalRef& inst,
+    jni::Object::Param aResult) {
+  auto geckoResult = java::GeckoResult::Ref::From(aResult);
+  RefPtr<CanonicalBrowsingContext> cbc = GetContentCanonicalBrowsingContext();
+  if (!cbc) {
+    geckoResult->CompleteExceptionally(
+        GeckoPrintException::New(
+            GeckoPrintException::
+                ERROR_UNABLE_TO_RETRIEVE_CANONICAL_BROWSING_CONTEXT)
+            .Cast<jni::Throwable>());
+    GVS_LOG("Could not retrieve content canonical browsing context.");
+    return;
+  }
+  CreatePdf(geckoResult, cbc);
+}
+
+void GeckoViewSupport::PrintToPdf(
+    const java::GeckoSession::Window::LocalRef& inst,
+    jni::Object::Param aResult, int64_t aBcId) {
+  auto geckoResult = java::GeckoResult::Ref::From(aResult);
+
+  RefPtr<CanonicalBrowsingContext> cbc = CanonicalBrowsingContext::Get(aBcId);
+  if (!cbc) {
+    geckoResult->CompleteExceptionally(
+        GeckoPrintException::New(
+            GeckoPrintException::
+                ERROR_UNABLE_TO_RETRIEVE_CANONICAL_BROWSING_CONTEXT)
+            .Cast<jni::Throwable>());
+    GVS_LOG("Could not retrieve content canonical browsing context by ID.");
+    return;
+  }
+  CreatePdf(geckoResult, cbc);
+}
+}  // namespace widget
+}  // namespace mozilla
+
+void nsWindow::InitNatives() {
+  jni::InitConversionStatics();
+  mozilla::widget::GeckoViewSupport::Base::Init();
+  mozilla::widget::LayerViewSupport::Init();
+  mozilla::widget::NPZCSupport::Init();
+
+  mozilla::widget::GeckoEditableSupport::Init();
+  a11y::SessionAccessibility::Init();
+}
+
+void nsWindow::DetachNatives() {
+  MOZ_ASSERT(NS_IsMainThread());
+  mEditableSupport.Detach();
+  mNPZCSupport.Detach();
+  mLayerViewSupport.Detach();
+  mSessionAccessibility.Detach();
+}
+
+/* static */
+already_AddRefed<nsWindow> nsWindow::From(nsPIDOMWindowOuter* aDOMWindow) {
+  nsCOMPtr<nsIWidget> widget = WidgetUtils::DOMWindowToWidget(aDOMWindow);
+  return From(widget);
+}
+
+/* static */
+already_AddRefed<nsWindow> nsWindow::From(nsIWidget* aWidget) {
+  // `widget` may be one of several different types in the parent
+  // process, including the Android nsWindow, PuppetWidget, etc. To
+  // ensure that the cast to the Android nsWindow is valid, we check that the
+  // widget is a top-level window and that its NS_NATIVE_WIDGET value is
+  // non-null, which is not the case for non-native widgets like
+  // PuppetWidget.
+  if (aWidget && aWidget->GetWindowType() == WindowType::TopLevel &&
+      aWidget->GetNativeData(NS_NATIVE_WIDGET) == aWidget) {
+    RefPtr<nsWindow> window = static_cast<nsWindow*>(aWidget);
+    return window.forget();
+  }
+  return nullptr;
+}
+
+nsWindow* nsWindow::TopWindow() {
+  if (!gTopLevelWindows.IsEmpty()) return gTopLevelWindows[0];
+  return nullptr;
+}
+
+void nsWindow::LogWindow(nsWindow* win, int index, int indent) {
+#if defined(DEBUG) || defined(FORCE_ALOG)
+  char spaces[] = "                    ";
+  spaces[indent < 20 ? indent : 20] = 0;
+  ALOG("%s [% 2d] 0x%p [parent 0x%p] [% 3d,% 3dx% 3d,% 3d] vis %d type %d",
+       spaces, index, win, win->mParent, win->mBounds.x, win->mBounds.y,
+       win->mBounds.width, win->mBounds.height, win->mIsVisible,
+       int(win->mWindowType));
+#endif
+}
+
+void nsWindow::DumpWindows() { DumpWindows(gTopLevelWindows); }
+
+void nsWindow::DumpWindows(const nsTArray<nsWindow*>& wins, int indent) {
+  for (uint32_t i = 0; i < wins.Length(); ++i) {
+    nsWindow* w = wins[i];
+    LogWindow(w, i, indent);
+    DumpWindows(w->mChildren, indent + 1);
+  }
+}
+
+nsWindow::nsWindow()
+    : mWidgetId(++sWidgetId),
+      mIsVisible(false),
+      mParent(nullptr),
+      mDynamicToolbarMaxHeight(0),
+      mSizeMode(nsSizeMode_Normal),
+      mIsFullScreen(false),
+      mCompositorWidgetDelegate(nullptr),
+      mDestroyMutex("nsWindow::mDestroyMutex") {}
+
+nsWindow::~nsWindow() {
+  gTopLevelWindows.RemoveElement(this);
+  ALOG("nsWindow %p destructor", (void*)this);
+  // The mCompositorSession should have been cleaned up in nsWindow::Destroy()
+  // DestroyLayerManager() will call DestroyCompositor() which will crash if
+  // called from nsBaseWidget destructor. See Bug 1392705
+  MOZ_ASSERT(!mCompositorSession);
+}
+
+bool nsWindow::IsTopLevel() {
+  return mWindowType == WindowType::TopLevel ||
+         mWindowType == WindowType::Dialog ||
+         mWindowType == WindowType::Invisible;
+}
+
+nsresult nsWindow::Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                          const LayoutDeviceIntRect& aRect,
+                          InitData* aInitData) {
+  ALOG("nsWindow[%p]::Create %p [%d %d %d %d]", (void*)this, (void*)aParent,
+       aRect.x, aRect.y, aRect.width, aRect.height);
+
+  nsWindow* parent = (nsWindow*)aParent;
+  if (aNativeParent) {
+    if (parent) {
+      ALOG(
+          "Ignoring native parent on Android window [%p], "
+          "since parent was specified (%p %p)",
+          (void*)this, (void*)aNativeParent, (void*)aParent);
+    } else {
+      parent = (nsWindow*)aNativeParent;
+    }
+  }
+
+  // A default size of 1x1 confuses MobileViewportManager, so
+  // use 0x0 instead. This is also a little more fitting since
+  // we don't yet have a surface yet (and therefore a valid size)
+  // and 0x0 is usually recognized as invalid.
+  LayoutDeviceIntRect rect = aRect;
+  if (aRect.width == 1 && aRect.height == 1) {
+    rect.width = 0;
+    rect.height = 0;
+  }
+
+  mBounds = rect;
+  SetSizeConstraints(SizeConstraints());
+
+  BaseCreate(nullptr, aInitData);
+
+  NS_ASSERTION(IsTopLevel() || parent,
+               "non-top-level window doesn't have a parent!");
+
+  if (IsTopLevel()) {
+    gTopLevelWindows.AppendElement(this);
+
+  } else if (parent) {
+    parent->mChildren.AppendElement(this);
+    mParent = parent;
+  }
+
+#ifdef DEBUG_ANDROID_WIDGET
+  DumpWindows();
+#endif
+
+  return NS_OK;
+}
+
+void nsWindow::Destroy() {
+  MutexAutoLock lock(mDestroyMutex);
+
+  nsBaseWidget::mOnDestroyCalled = true;
+
+  // Disassociate our native object from GeckoView.
+  mGeckoViewSupport.Detach();
+
+  // Stuff below may release the last ref to this
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
+
+  while (mChildren.Length()) {
+    // why do we still have children?
+    ALOG("### Warning: Destroying window %p and reparenting child %p to null!",
+         (void*)this, (void*)mChildren[0]);
+    mChildren[0]->SetParent(nullptr);
+  }
+
+  // Ensure the compositor has been shutdown before this nsWindow is potentially
+  // deleted
+  nsBaseWidget::DestroyCompositor();
+
+  nsBaseWidget::Destroy();
+
+  if (IsTopLevel()) gTopLevelWindows.RemoveElement(this);
+
+  SetParent(nullptr);
+
+  nsBaseWidget::OnDestroy();
+
+#ifdef DEBUG_ANDROID_WIDGET
+  DumpWindows();
+#endif
+}
+
+mozilla::widget::EventDispatcher* nsWindow::GetEventDispatcher() const {
+  if (mAndroidView) {
+    return mAndroidView->mEventDispatcher;
+  }
+  return nullptr;
+}
+
+void nsWindow::RedrawAll() {
+  if (mAttachedWidgetListener) {
+    mAttachedWidgetListener->RequestRepaint();
+  } else if (mWidgetListener) {
+    mWidgetListener->RequestRepaint();
+  }
+}
+
+RefPtr<UiCompositorControllerChild> nsWindow::GetUiCompositorControllerChild() {
+  return mCompositorSession
+             ? mCompositorSession->GetUiCompositorControllerChild()
+             : nullptr;
+}
+
+mozilla::layers::LayersId nsWindow::GetRootLayerId() const {
+  return mCompositorSession ? mCompositorSession->RootLayerTreeId()
+                            : mozilla::layers::LayersId{0};
+}
+
+void nsWindow::OnGeckoViewReady() {
+  auto acc(mGeckoViewSupport.Access());
+  if (!acc) {
+    return;
+  }
+
+  acc->OnReady();
+}
+
+void nsWindow::SetParent(nsIWidget* aNewParent) {
+  if ((nsIWidget*)mParent == aNewParent) return;
+
+  // If we had a parent before, remove ourselves from its list of
+  // children.
+  if (mParent) mParent->mChildren.RemoveElement(this);
+
+  mParent = (nsWindow*)aNewParent;
+
+  if (mParent) mParent->mChildren.AppendElement(this);
+
+  // if we are now in the toplevel window's hierarchy, schedule a redraw
+  if (FindTopLevel() == nsWindow::TopWindow()) RedrawAll();
+}
+
+nsIWidget* nsWindow::GetParent() { return mParent; }
+
+RefPtr<MozPromise<bool, bool, false>> nsWindow::OnLoadRequest(
+    nsIURI* aUri, int32_t aWindowType, int32_t aFlags,
+    nsIPrincipal* aTriggeringPrincipal, bool aHasUserGesture,
+    bool aIsTopLevel) {
+  auto geckoViewSupport(mGeckoViewSupport.Access());
+  if (!geckoViewSupport) {
+    return MozPromise<bool, bool, false>::CreateAndResolve(false, __func__);
+  }
+
+  nsAutoCString spec, triggeringSpec;
+  if (aUri) {
+    aUri->GetDisplaySpec(spec);
+    if (aIsTopLevel && mozilla::net::SchemeIsData(aUri) &&
+        spec.Length() > MAX_TOPLEVEL_DATA_URI_LEN) {
+      return MozPromise<bool, bool, false>::CreateAndResolve(false, __func__);
+    }
+  }
+
+  bool isNullPrincipal = false;
+  if (aTriggeringPrincipal) {
+    aTriggeringPrincipal->GetIsNullPrincipal(&isNullPrincipal);
+
+    if (!isNullPrincipal) {
+      nsCOMPtr<nsIURI> triggeringUri;
+      BasePrincipal::Cast(aTriggeringPrincipal)
+          ->GetURI(getter_AddRefs(triggeringUri));
+      if (triggeringUri) {
+        triggeringUri->GetDisplaySpec(triggeringSpec);
+      }
+    }
+  }
+
+  auto geckoResult = geckoViewSupport->OnLoadRequest(
+      spec.get(), aWindowType, aFlags,
+      isNullPrincipal ? nullptr : triggeringSpec.get(), aHasUserGesture,
+      aIsTopLevel);
+  return geckoResult
+             ? MozPromise<bool, bool, false>::FromGeckoResult(geckoResult)
+             : nullptr;
+}
+
+void nsWindow::OnUpdateSessionStore(mozilla::jni::Object::Param aBundle) {
+  auto geckoViewSupport(mGeckoViewSupport.Access());
+  if (!geckoViewSupport) {
+    return;
+  }
+
+  geckoViewSupport->OnUpdateSessionStore(aBundle);
+}
+
+float nsWindow::GetDPI() {
+  float dpi = 160.0f;
+
+  nsCOMPtr<nsIScreen> screen = GetWidgetScreen();
+  if (screen) {
+    screen->GetDpi(&dpi);
+  }
+
+  return dpi;
+}
+
+double nsWindow::GetDefaultScaleInternal() {
+  double scale = 1.0f;
+
+  nsCOMPtr<nsIScreen> screen = GetWidgetScreen();
+  if (screen) {
+    screen->GetContentsScaleFactor(&scale);
+  }
+
+  return scale;
+}
+
+void nsWindow::Show(bool aState) {
+  ALOG("nsWindow[%p]::Show %d", (void*)this, aState);
+
+  if (mWindowType == WindowType::Invisible) {
+    ALOG("trying to show invisible window! ignoring..");
+    return;
+  }
+
+  if (aState == mIsVisible) return;
+
+  mIsVisible = aState;
+
+  if (IsTopLevel()) {
+    // XXX should we bring this to the front when it's shown,
+    // if it's a toplevel widget?
+
+    // XXX we should synthesize a eMouseExitFromWidget (for old top
+    // window)/eMouseEnterIntoWidget (for new top window) since we need
+    // to pretend that the top window always has focus.  Not sure
+    // if Show() is the right place to do this, though.
+
+    if (aState) {
+      // It just became visible, so bring it to the front.
+      BringToFront();
+
+    } else if (nsWindow::TopWindow() == this) {
+      // find the next visible window to show
+      unsigned int i;
+      for (i = 1; i < gTopLevelWindows.Length(); i++) {
+        nsWindow* win = gTopLevelWindows[i];
+        if (!win->mIsVisible) continue;
+
+        win->BringToFront();
+        break;
+      }
+    }
+  } else if (FindTopLevel() == nsWindow::TopWindow()) {
+    RedrawAll();
+  }
+
+#ifdef DEBUG_ANDROID_WIDGET
+  DumpWindows();
+#endif
+}
+
+bool nsWindow::IsVisible() const { return mIsVisible; }
+
+void nsWindow::ConstrainPosition(DesktopIntPoint& aPoint) {
+  ALOG("nsWindow[%p]::ConstrainPosition [%d %d]", (void*)this, aPoint.x.value,
+       aPoint.y.value);
+
+  // Constrain toplevel windows; children we don't care about
+  if (IsTopLevel()) {
+    aPoint = DesktopIntPoint();
+  }
+}
+
+void nsWindow::Move(double aX, double aY) {
+  if (IsTopLevel()) return;
+
+  Resize(aX, aY, mBounds.width, mBounds.height, true);
+}
+
+void nsWindow::Resize(double aWidth, double aHeight, bool aRepaint) {
+  Resize(mBounds.x, mBounds.y, aWidth, aHeight, aRepaint);
+}
+
+void nsWindow::Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) {
+  ALOG("nsWindow[%p]::Resize [%f %f %f %f] (repaint %d)", (void*)this, aX, aY,
+       aWidth, aHeight, aRepaint);
+
+  LayoutDeviceIntRect oldBounds = mBounds;
+
+  mBounds.x = NSToIntRound(aX);
+  mBounds.y = NSToIntRound(aY);
+  mBounds.width = NSToIntRound(aWidth);
+  mBounds.height = NSToIntRound(aHeight);
+
+  ConstrainSize(&mBounds.width, &mBounds.height);
+
+  bool needPositionDispatch = mBounds.TopLeft() != oldBounds.TopLeft();
+  bool needSizeDispatch = mBounds.Size() != oldBounds.Size();
+
+  if (needSizeDispatch) {
+    OnSizeChanged(mBounds.Size().ToUnknownSize());
+  }
+
+  if (needPositionDispatch) {
+    NotifyWindowMoved(mBounds.x, mBounds.y);
+  }
+
+  // Should we skip honoring aRepaint here?
+  if (aRepaint && FindTopLevel() == nsWindow::TopWindow()) RedrawAll();
+}
+
+void nsWindow::SetZIndex(int32_t aZIndex) {
+  ALOG("nsWindow[%p]::SetZIndex %d ignored", (void*)this, aZIndex);
+}
+
+void nsWindow::SetSizeMode(nsSizeMode aMode) {
+  if (aMode == mSizeMode) {
+    return;
+  }
+
+  mSizeMode = aMode;
+
+  switch (aMode) {
+    case nsSizeMode_Minimized:
+      java::GeckoAppShell::MoveTaskToBack();
+      break;
+    case nsSizeMode_Fullscreen:
+      MakeFullScreen(true);
+      break;
+    default:
+      break;
+  }
+}
+
+void nsWindow::Enable(bool aState) {
+  ALOG("nsWindow[%p]::Enable %d ignored", (void*)this, aState);
+}
+
+bool nsWindow::IsEnabled() const { return true; }
+
+void nsWindow::Invalidate(const LayoutDeviceIntRect& aRect) {}
+
+nsWindow* nsWindow::FindTopLevel() {
+  nsWindow* toplevel = this;
+  while (toplevel) {
+    if (toplevel->IsTopLevel()) return toplevel;
+
+    toplevel = toplevel->mParent;
+  }
+
+  ALOG(
+      "nsWindow::FindTopLevel(): couldn't find a toplevel or dialog window in "
+      "this [%p] widget's hierarchy!",
+      (void*)this);
+  return this;
+}
+
+void nsWindow::SetFocus(Raise, mozilla::dom::CallerType aCallerType) {
+  FindTopLevel()->BringToFront();
+}
+
+void nsWindow::BringToFront() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  // If the window to be raised is the same as the currently raised one,
+  // do nothing. We need to check the focus manager as well, as the first
+  // window that is created will be first in the window list but won't yet
+  // be focused.
+  nsFocusManager* fm = nsFocusManager::GetFocusManager();
+  if (fm && fm->GetActiveWindow() && FindTopLevel() == nsWindow::TopWindow()) {
+    return;
+  }
+
+  if (!IsTopLevel()) {
+    FindTopLevel()->BringToFront();
+    return;
+  }
+
+  RefPtr<nsWindow> kungFuDeathGrip(this);
+
+  nsWindow* oldTop = nullptr;
+  if (!gTopLevelWindows.IsEmpty()) {
+    oldTop = gTopLevelWindows[0];
+  }
+
+  gTopLevelWindows.RemoveElement(this);
+  gTopLevelWindows.InsertElementAt(0, this);
+
+  if (oldTop) {
+    nsIWidgetListener* listener = oldTop->GetWidgetListener();
+    if (listener) {
+      listener->WindowDeactivated();
+    }
+  }
+
+  if (mWidgetListener) {
+    mWidgetListener->WindowActivated();
+  }
+
+  RedrawAll();
+}
+
+LayoutDeviceIntRect nsWindow::GetScreenBounds() {
+  return LayoutDeviceIntRect(WidgetToScreenOffset(), mBounds.Size());
+}
+
+LayoutDeviceIntPoint nsWindow::WidgetToScreenOffset() {
+  LayoutDeviceIntPoint p(0, 0);
+
+  for (nsWindow* w = this; !!w; w = w->mParent) {
+    p.x += w->mBounds.x;
+    p.y += w->mBounds.y;
+
+    if (w->IsTopLevel()) {
+      break;
+    }
+  }
+  return p;
+}
+
+nsresult nsWindow::DispatchEvent(WidgetGUIEvent* aEvent,
+                                 nsEventStatus& aStatus) {
+  aStatus = DispatchEvent(aEvent);
+  return NS_OK;
+}
+
+nsEventStatus nsWindow::DispatchEvent(WidgetGUIEvent* aEvent) {
+  if (mAttachedWidgetListener) {
+    return mAttachedWidgetListener->HandleEvent(aEvent, mUseAttachedEvents);
+  } else if (mWidgetListener) {
+    return mWidgetListener->HandleEvent(aEvent, mUseAttachedEvents);
+  }
+  return nsEventStatus_eIgnore;
+}
+
+nsresult nsWindow::MakeFullScreen(bool aFullScreen) {
+  if (!mAndroidView) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  mIsFullScreen = aFullScreen;
+  mAndroidView->mEventDispatcher->Dispatch(
+      aFullScreen ? u"GeckoView:FullScreenEnter" : u"GeckoView:FullScreenExit");
+
+  nsIWidgetListener* listener = GetWidgetListener();
+  if (listener) {
+    mSizeMode = mIsFullScreen ? nsSizeMode_Fullscreen : nsSizeMode_Normal;
+    listener->SizeModeChanged(mSizeMode);
+  }
+  return NS_OK;
+}
+
+mozilla::WindowRenderer* nsWindow::GetWindowRenderer() {
+  if (!mWindowRenderer) {
+    CreateLayerManager();
+  }
+
+  return mWindowRenderer;
+}
+
+void nsWindow::CreateLayerManager() {
+  if (mWindowRenderer) {
+    return;
+  }
+
+  nsWindow* topLevelWindow = FindTopLevel();
+  if (!topLevelWindow || topLevelWindow->mWindowType == WindowType::Invisible) {
+    // don't create a layer manager for an invisible top-level window
+    return;
+  }
+
+  // Ensure that gfxPlatform is initialized first.
+  gfxPlatform::GetPlatform();
+
+  if (ShouldUseOffMainThreadCompositing()) {
+    LayoutDeviceIntRect rect = GetBounds();
+    CreateCompositor(rect.Width(), rect.Height());
+    if (mWindowRenderer) {
+      if (mLayerViewSupport.IsAttached()) {
+        DispatchToUiThread(
+            "LayerViewSupport::NotifyCompositorCreated",
+            [lvs = mLayerViewSupport,
+             uiCompositorController = GetUiCompositorControllerChild()] {
+              if (auto lvsAccess{lvs.Access()}) {
+                lvsAccess->NotifyCompositorCreated(uiCompositorController);
+              }
+            });
+      }
+
+      return;
+    }
+
+    // If we get here, then off main thread compositing failed to initialize.
+    sFailedToCreateGLContext = true;
+  }
+
+  if (!ComputeShouldAccelerate() || sFailedToCreateGLContext) {
+    printf_stderr(" -- creating basic, not accelerated\n");
+    mWindowRenderer = CreateFallbackRenderer();
+  }
+}
+
+void nsWindow::NotifyCompositorSessionLost(
+    mozilla::layers::CompositorSession* aSession) {
+  nsBaseWidget::NotifyCompositorSessionLost(aSession);
+
+  DispatchToUiThread("nsWindow::NotifyCompositorSessionLost",
+                     [lvs = mLayerViewSupport] {
+                       if (auto lvsAccess{lvs.Access()}) {
+                         lvsAccess->NotifyCompositorSessionLost();
+                       }
+                     });
+
+  RedrawAll();
+}
+
+void nsWindow::ShowDynamicToolbar() {
+  auto acc(mGeckoViewSupport.Access());
+  if (!acc) {
+    return;
+  }
+
+  acc->OnShowDynamicToolbar();
+}
+
+void GeckoViewSupport::OnUpdateSessionStore(
+    mozilla::jni::Object::Param aBundle) {
+  GeckoSession::Window::LocalRef window(mGeckoViewWindow);
+  if (!window) {
+    return;
+  }
+
+  window->OnUpdateSessionStore(aBundle);
+}
+
+static EventMessage convertDragEventActionToGeckoEvent(int32_t aAction) {
+  switch (aAction) {
+    case java::sdk::DragEvent::ACTION_DRAG_ENTERED:
+      return eDragEnter;
+    case java::sdk::DragEvent::ACTION_DRAG_EXITED:
+      return eDragExit;
+    case java::sdk::DragEvent::ACTION_DRAG_LOCATION:
+      return eDragOver;
+    case java::sdk::DragEvent::ACTION_DROP:
+      return eDrop;
+  }
+  return eVoidEvent;
+}
+
+void nsWindow::OnDragEvent(int32_t aAction, int64_t aTime, float aX, float aY,
+                           jni::Object::Param aDropData) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  RefPtr<nsDragService> dragService = nsDragService::GetInstance();
+  if (!dragService) {
+    return;
+  }
+
+  LayoutDeviceIntPoint point =
+      LayoutDeviceIntPoint(int32_t(floorf(aX)), int32_t(floorf(aY)));
+
+  if (aAction == java::sdk::DragEvent::ACTION_DRAG_STARTED) {
+    dragService->SetDragEndPoint(point);
+    return;
+  }
+
+  if (aAction == java::sdk::DragEvent::ACTION_DRAG_ENDED) {
+    dragService->EndDragSession(false, 0);
+    return;
+  }
+
+  EventMessage message = convertDragEventActionToGeckoEvent(aAction);
+
+  if (message == eDragEnter) {
+    dragService->StartDragSession();
+    // For compatibility, we have to set temporary data.
+    auto dropData =
+        mozilla::java::GeckoDragAndDrop::DropData::Ref::From(aDropData);
+    nsDragService::SetDropData(dropData);
+  }
+
+  nsCOMPtr<nsIDragSession> dragSession;
+  dragService->GetCurrentSession(getter_AddRefs(dragSession));
+  if (dragSession) {
+    switch (message) {
+      case eDragOver:
+        dragService->SetDragEndPoint(point);
+        dragService->FireDragEventAtSource(eDrag, 0);
+        break;
+      case eDrop: {
+        bool canDrop = false;
+        dragSession->GetCanDrop(&canDrop);
+        if (!canDrop) {
+          nsCOMPtr<nsINode> sourceNode;
+          dragSession->GetSourceNode(getter_AddRefs(sourceNode));
+          if (!sourceNode) {
+            dragService->EndDragSession(false, 0);
+          }
+          return;
+        }
+        auto dropData =
+            mozilla::java::GeckoDragAndDrop::DropData::Ref::From(aDropData);
+        nsDragService::SetDropData(dropData);
+        dragService->SetDragEndPoint(point);
+        break;
+      }
+      default:
+        break;
+    }
+
+    dragSession->SetDragAction(nsIDragService::DRAGDROP_ACTION_MOVE);
+  }
+
+  WidgetDragEvent geckoEvent(true, message, this);
+  geckoEvent.mRefPoint = point;
+  geckoEvent.mTimeStamp = nsWindow::GetEventTimeStamp(aTime);
+  geckoEvent.mModifiers = 0;  // DragEvent has no modifiers
+  DispatchInputEvent(&geckoEvent);
+
+  if (!dragSession) {
+    return;
+  }
+
+  switch (message) {
+    case eDragExit: {
+      nsCOMPtr<nsINode> sourceNode;
+      dragSession->GetSourceNode(getter_AddRefs(sourceNode));
+      if (!sourceNode) {
+        // We're leaving a window while doing a drag that was
+        // initiated in a different app. End the drag session,
+        // since we're done with it for now (until the user
+        // drags back into mozilla).
+        dragService->EndDragSession(false, 0);
+      }
+      break;
+    }
+    case eDrop:
+      dragService->EndDragSession(true, 0);
+      break;
+    default:
+      break;
+  }
+}
+
+void nsWindow::StartDragAndDrop(java::sdk::Bitmap::LocalRef aBitmap) {
+  if (mozilla::jni::NativeWeakPtr<LayerViewSupport>::Accessor lvs{
+          mLayerViewSupport.Access()}) {
+    const auto& compositor = lvs->GetJavaCompositor();
+
+    DispatchToUiThread(
+        "nsWindow::StartDragAndDrop",
+        [compositor = GeckoSession::Compositor::GlobalRef(compositor),
+         bitmap = java::sdk::Bitmap::GlobalRef(aBitmap)] {
+          compositor->StartDragAndDrop(bitmap);
+        });
+  }
+}
+
+void nsWindow::UpdateDragImage(java::sdk::Bitmap::LocalRef aBitmap) {
+  if (mozilla::jni::NativeWeakPtr<LayerViewSupport>::Accessor lvs{
+          mLayerViewSupport.Access()}) {
+    const auto& compositor = lvs->GetJavaCompositor();
+
+    DispatchToUiThread(
+        "nsWindow::UpdateDragImage",
+        [compositor = GeckoSession::Compositor::GlobalRef(compositor),
+         bitmap = java::sdk::Bitmap::GlobalRef(aBitmap)] {
+          compositor->UpdateDragImage(bitmap);
+        });
+  }
+}
+
+void nsWindow::OnSizeChanged(const gfx::IntSize& aSize) {
+  ALOG("nsWindow: %p OnSizeChanged [%d %d]", (void*)this, aSize.width,
+       aSize.height);
+
+  if (mWidgetListener) {
+    mWidgetListener->WindowResized(this, aSize.width, aSize.height);
+  }
+
+  if (mAttachedWidgetListener) {
+    mAttachedWidgetListener->WindowResized(this, aSize.width, aSize.height);
+  }
+
+  if (mCompositorWidgetDelegate) {
+    mCompositorWidgetDelegate->NotifyClientSizeChanged(
+        LayoutDeviceIntSize::FromUnknownSize(aSize));
+  }
+}
+
+void nsWindow::InitEvent(WidgetGUIEvent& event, LayoutDeviceIntPoint* aPoint) {
+  if (aPoint) {
+    event.mRefPoint = *aPoint;
+  } else {
+    event.mRefPoint = LayoutDeviceIntPoint(0, 0);
+  }
+}
+
+void nsWindow::UpdateOverscrollVelocity(const float aX, const float aY) {
+  if (::mozilla::jni::NativeWeakPtr<LayerViewSupport>::Accessor lvs{
+          mLayerViewSupport.Access()}) {
+    const auto& compositor = lvs->GetJavaCompositor();
+    if (AndroidBridge::IsJavaUiThread()) {
+      compositor->UpdateOverscrollVelocity(aX, aY);
+      return;
+    }
+
+    DispatchToUiThread(
+        "nsWindow::UpdateOverscrollVelocity",
+        [compositor = GeckoSession::Compositor::GlobalRef(compositor), aX, aY] {
+          compositor->UpdateOverscrollVelocity(aX, aY);
+        });
+  }
+}
+
+void nsWindow::UpdateOverscrollOffset(const float aX, const float aY) {
+  if (::mozilla::jni::NativeWeakPtr<LayerViewSupport>::Accessor lvs{
+          mLayerViewSupport.Access()}) {
+    const auto& compositor = lvs->GetJavaCompositor();
+    if (AndroidBridge::IsJavaUiThread()) {
+      compositor->UpdateOverscrollOffset(aX, aY);
+      return;
+    }
+
+    DispatchToUiThread(
+        "nsWindow::UpdateOverscrollOffset",
+        [compositor = GeckoSession::Compositor::GlobalRef(compositor), aX, aY] {
+          compositor->UpdateOverscrollOffset(aX, aY);
+        });
+  }
+}
+
+void* nsWindow::GetNativeData(uint32_t aDataType) {
+  switch (aDataType) {
+    // used by GLContextProviderEGL, nullptr is EGL_DEFAULT_DISPLAY
+    case NS_NATIVE_WIDGET:
+      return (void*)this;
+
+    case NS_RAW_NATIVE_IME_CONTEXT: {
+      void* pseudoIMEContext = GetPseudoIMEContext();
+      if (pseudoIMEContext) {
+        return pseudoIMEContext;
+      }
+      // We assume that there is only one context per process on Android
+      return NS_ONLY_ONE_NATIVE_IME_CONTEXT;
+    }
+
+    case NS_JAVA_SURFACE:
+      if (::mozilla::jni::NativeWeakPtr<LayerViewSupport>::Accessor lvs{
+              mLayerViewSupport.Access()}) {
+        return lvs->GetSurface().Get();
+      }
+      return nullptr;
+  }
+
+  return nullptr;
+}
+
+void nsWindow::DispatchHitTest(const WidgetTouchEvent& aEvent) {
+  if (aEvent.mMessage == eTouchStart && aEvent.mTouches.Length() == 1) {
+    // Since touch events don't get retargeted by PositionedEventTargeting.cpp
+    // code, we dispatch a dummy mouse event that *does* get retargeted.
+    // Front-end code can use this to activate the highlight element in case
+    // this touchstart is the start of a tap.
+    WidgetMouseEvent hittest(true, eMouseHitTest, this,
+                             WidgetMouseEvent::eReal);
+    hittest.mRefPoint = aEvent.mTouches[0]->mRefPoint;
+    hittest.mInputSource = MouseEvent_Binding::MOZ_SOURCE_TOUCH;
+    nsEventStatus status;
+    DispatchEvent(&hittest, status);
+  }
+}
+
+void nsWindow::PassExternalResponse(java::WebResponse::Param aResponse) {
+  auto acc(mGeckoViewSupport.Access());
+  if (!acc) {
+    return;
+  }
+
+  acc->PassExternalResponse(aResponse);
+}
+
+mozilla::Modifiers nsWindow::GetModifiers(int32_t metaState) {
+  using mozilla::java::sdk::KeyEvent;
+  return (metaState & KeyEvent::META_ALT_MASK ? MODIFIER_ALT : 0) |
+         (metaState & KeyEvent::META_SHIFT_MASK ? MODIFIER_SHIFT : 0) |
+         (metaState & KeyEvent::META_CTRL_MASK ? MODIFIER_CONTROL : 0) |
+         (metaState & KeyEvent::META_META_MASK ? MODIFIER_META : 0) |
+         (metaState & KeyEvent::META_FUNCTION_ON ? MODIFIER_FN : 0) |
+         (metaState & KeyEvent::META_CAPS_LOCK_ON ? MODIFIER_CAPSLOCK : 0) |
+         (metaState & KeyEvent::META_NUM_LOCK_ON ? MODIFIER_NUMLOCK : 0) |
+         (metaState & KeyEvent::META_SCROLL_LOCK_ON ? MODIFIER_SCROLLLOCK : 0);
+}
+
+TimeStamp nsWindow::GetEventTimeStamp(int64_t aEventTime) {
+  // Android's event time is SystemClock.uptimeMillis that is counted in ms
+  // since OS was booted.
+  // (https://developer.android.com/reference/android/os/SystemClock.html)
+  // and this SystemClock.uptimeMillis uses SYSTEM_TIME_MONOTONIC.
+  // Our posix implemententaion of TimeStamp::Now uses SYSTEM_TIME_MONOTONIC
+  //  too. Due to same implementation, we can use this via FromSystemTime.
+  int64_t tick =
+      BaseTimeDurationPlatformUtils::TicksFromMilliseconds(aEventTime);
+  return TimeStamp::FromSystemTime(tick);
+}
+
+void nsWindow::UserActivity() {
+  if (!mIdleService) {
+    mIdleService = do_GetService("@mozilla.org/widget/useridleservice;1");
+  }
+
+  if (mIdleService) {
+    mIdleService->ResetIdleTimeOut(0);
+  }
+
+  if (FindTopLevel() != nsWindow::TopWindow()) {
+    BringToFront();
+  }
+}
+
+RefPtr<mozilla::a11y::SessionAccessibility>
+nsWindow::GetSessionAccessibility() {
+  auto acc(mSessionAccessibility.Access());
+  if (!acc) {
+    return nullptr;
+  }
+
+  return acc.AsRefPtr();
+}
+
+TextEventDispatcherListener* nsWindow::GetNativeTextEventDispatcherListener() {
+  nsWindow* top = FindTopLevel();
+  MOZ_ASSERT(top);
+
+  auto acc(top->mEditableSupport.Access());
+  if (!acc) {
+    // Non-GeckoView windows don't support IME operations.
+    return nullptr;
+  }
+
+  nsCOMPtr<TextEventDispatcherListener> ptr;
+  if (NS_FAILED(acc->QueryInterface(NS_GET_IID(TextEventDispatcherListener),
+                                    getter_AddRefs(ptr)))) {
+    return nullptr;
+  }
+
+  return ptr.get();
+}
+
+void nsWindow::SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction) {
+  nsWindow* top = FindTopLevel();
+  MOZ_ASSERT(top);
+
+  auto acc(top->mEditableSupport.Access());
+  if (!acc) {
+    // Non-GeckoView windows don't support IME operations.
+    return;
+  }
+
+  // We are using an IME event later to notify Java, and the IME event
+  // will be processed by the top window. Therefore, to ensure the
+  // IME event uses the correct mInputContext, we need to let the top
+  // window process SetInputContext
+  acc->SetInputContext(aContext, aAction);
+}
+
+InputContext nsWindow::GetInputContext() {
+  nsWindow* top = FindTopLevel();
+  MOZ_ASSERT(top);
+
+  auto acc(top->mEditableSupport.Access());
+  if (!acc) {
+    // Non-GeckoView windows don't support IME operations.
+    return InputContext();
+  }
+
+  // We let the top window process SetInputContext,
+  // so we should let it process GetInputContext as well.
+  return acc->GetInputContext();
+}
+
+nsresult nsWindow::SynthesizeNativeTouchPoint(uint32_t aPointerId,
+                                              TouchPointerState aPointerState,
+                                              LayoutDeviceIntPoint aPoint,
+                                              double aPointerPressure,
+                                              uint32_t aPointerOrientation,
+                                              nsIObserver* aObserver) {
+  mozilla::widget::AutoObserverNotifier notifier(aObserver, "touchpoint");
+
+  int eventType;
+  switch (aPointerState) {
+    case TOUCH_CONTACT:
+      // This could be a ACTION_DOWN or ACTION_MOVE depending on the
+      // existing state; it is mapped to the right thing in Java.
+      eventType = java::sdk::MotionEvent::ACTION_POINTER_DOWN;
+      break;
+    case TOUCH_REMOVE:
+      // This could be turned into a ACTION_UP in Java
+      eventType = java::sdk::MotionEvent::ACTION_POINTER_UP;
+      break;
+    case TOUCH_CANCEL:
+      eventType = java::sdk::MotionEvent::ACTION_CANCEL;
+      break;
+    case TOUCH_HOVER:  // not supported for now
+    default:
+      return NS_ERROR_UNEXPECTED;
+  }
+
+  MOZ_ASSERT(mNPZCSupport.IsAttached());
+  auto npzcSup(mNPZCSupport.Access());
+  MOZ_ASSERT(!!npzcSup);
+
+  const auto& npzc = npzcSup->GetJavaNPZC();
+  const auto& bounds = FindTopLevel()->mBounds;
+  aPoint.x -= bounds.x;
+  aPoint.y -= bounds.y;
+
+  DispatchToUiThread(
+      "nsWindow::SynthesizeNativeTouchPoint",
+      [npzc = java::PanZoomController::NativeProvider::GlobalRef(npzc),
+       aPointerId, eventType, aPoint, aPointerPressure, aPointerOrientation] {
+        npzc->SynthesizeNativeTouchPoint(aPointerId, eventType, aPoint.x,
+                                         aPoint.y, aPointerPressure,
+                                         aPointerOrientation);
+      });
+  return NS_OK;
+}
+
+nsresult nsWindow::SynthesizeNativeMouseEvent(
+    LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+    MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+    nsIObserver* aObserver) {
+  mozilla::widget::AutoObserverNotifier notifier(aObserver, "mouseevent");
+
+  MOZ_ASSERT(mNPZCSupport.IsAttached());
+  auto npzcSup(mNPZCSupport.Access());
+  MOZ_ASSERT(!!npzcSup);
+
+  const auto& npzc = npzcSup->GetJavaNPZC();
+  const auto& bounds = FindTopLevel()->mBounds;
+  aPoint.x -= bounds.x;
+  aPoint.y -= bounds.y;
+
+  int32_t nativeMessage;
+  switch (aNativeMessage) {
+    case NativeMouseMessage::ButtonDown:
+      nativeMessage = java::sdk::MotionEvent::ACTION_POINTER_DOWN;
+      break;
+    case NativeMouseMessage::ButtonUp:
+      nativeMessage = java::sdk::MotionEvent::ACTION_POINTER_UP;
+      break;
+    case NativeMouseMessage::Move:
+      nativeMessage = java::sdk::MotionEvent::ACTION_HOVER_MOVE;
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE("Non supported mouse event on Android");
+      return NS_ERROR_INVALID_ARG;
+  }
+  int32_t button = 0;
+  if (aNativeMessage != NativeMouseMessage::ButtonUp) {
+    switch (aButton) {
+      case MouseButton::ePrimary:
+        button = java::sdk::MotionEvent::BUTTON_PRIMARY;
+        break;
+      case MouseButton::eMiddle:
+        button = java::sdk::MotionEvent::BUTTON_TERTIARY;
+        break;
+      case MouseButton::eSecondary:
+        button = java::sdk::MotionEvent::BUTTON_SECONDARY;
+        break;
+      case MouseButton::eX1:
+        button = java::sdk::MotionEvent::BUTTON_BACK;
+        break;
+      case MouseButton::eX2:
+        button = java::sdk::MotionEvent::BUTTON_FORWARD;
+        break;
+      default:
+        if (aNativeMessage == NativeMouseMessage::ButtonDown) {
+          MOZ_ASSERT_UNREACHABLE("Non supported mouse button type on Android");
+          return NS_ERROR_INVALID_ARG;
+        }
+        break;
+    }
+  }
+
+  // TODO (bug 1693237): Handle aModifierFlags.
+  DispatchToUiThread(
+      "nsWindow::SynthesizeNativeMouseEvent",
+      [npzc = java::PanZoomController::NativeProvider::GlobalRef(npzc),
+       nativeMessage, aPoint, button] {
+        npzc->SynthesizeNativeMouseEvent(nativeMessage, aPoint.x, aPoint.y,
+                                         button);
+      });
+  return NS_OK;
+}
+
+nsresult nsWindow::SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
+                                             nsIObserver* aObserver) {
+  return SynthesizeNativeMouseEvent(
+      aPoint, NativeMouseMessage::Move, MouseButton::eNotPressed,
+      nsIWidget::Modifiers::NO_MODIFIERS, aObserver);
+}
+
+void nsWindow::SetCompositorWidgetDelegate(CompositorWidgetDelegate* delegate) {
+  if (delegate) {
+    mCompositorWidgetDelegate = delegate->AsPlatformSpecificDelegate();
+    MOZ_ASSERT(mCompositorWidgetDelegate,
+               "nsWindow::SetCompositorWidgetDelegate called with a "
+               "non-PlatformCompositorWidgetDelegate");
+  } else {
+    mCompositorWidgetDelegate = nullptr;
+  }
+}
+
+void nsWindow::GetCompositorWidgetInitData(
+    mozilla::widget::CompositorWidgetInitData* aInitData) {
+  *aInitData = mozilla::widget::AndroidCompositorWidgetInitData(
+      mWidgetId, GetClientSize());
+}
+
+bool nsWindow::WidgetPaintsBackground() {
+  return StaticPrefs::android_widget_paints_background();
+}
+
+bool nsWindow::NeedsPaint() {
+  auto lvs(mLayerViewSupport.Access());
+  if (!lvs || lvs->CompositorPaused() || !GetWindowRenderer()) {
+    return false;
+  }
+
+  return nsIWidget::NeedsPaint();
+}
+
+void nsWindow::ConfigureAPZControllerThread() {
+  nsCOMPtr<nsISerialEventTarget> thread = mozilla::GetAndroidUiThread();
+  APZThreadUtils::SetControllerThread(thread);
+}
+
+already_AddRefed<GeckoContentController>
+nsWindow::CreateRootContentController() {
+  RefPtr<GeckoContentController> controller =
+      new AndroidContentController(this, mAPZEventState, mAPZC);
+  return controller.forget();
+}
+
+uint32_t nsWindow::GetMaxTouchPoints() const {
+  return java::GeckoAppShell::GetMaxTouchPoints();
+}
+
+void nsWindow::UpdateZoomConstraints(
+    const uint32_t& aPresShellId, const ScrollableLayerGuid::ViewID& aViewId,
+    const mozilla::Maybe<ZoomConstraints>& aConstraints) {
+  nsBaseWidget::UpdateZoomConstraints(aPresShellId, aViewId, aConstraints);
+}
+
+CompositorBridgeChild* nsWindow::GetCompositorBridgeChild() const {
+  return mCompositorSession ? mCompositorSession->GetCompositorBridgeChild()
+                            : nullptr;
+}
+
+void nsWindow::SetContentDocumentDisplayed(bool aDisplayed) {
+  mContentDocumentDisplayed = aDisplayed;
+}
+
+bool nsWindow::IsContentDocumentDisplayed() {
+  return mContentDocumentDisplayed;
+}
+
+void nsWindow::RecvToolbarAnimatorMessageFromCompositor(int32_t aMessage) {
+  MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+  if (::mozilla::jni::NativeWeakPtr<LayerViewSupport>::Accessor lvs{
+          mLayerViewSupport.Access()}) {
+    lvs->RecvToolbarAnimatorMessage(aMessage);
+  }
+}
+
+void nsWindow::UpdateRootFrameMetrics(const ScreenPoint& aScrollOffset,
+                                      const CSSToScreenScale& aZoom) {
+  MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+  if (::mozilla::jni::NativeWeakPtr<LayerViewSupport>::Accessor lvs{
+          mLayerViewSupport.Access()}) {
+    const auto& compositor = lvs->GetJavaCompositor();
+    mContentDocumentDisplayed = true;
+    compositor->UpdateRootFrameMetrics(aScrollOffset.x, aScrollOffset.y,
+                                       aZoom.scale);
+  }
+}
+
+void nsWindow::RecvScreenPixels(Shmem&& aMem, const ScreenIntSize& aSize,
+                                bool aNeedsYFlip) {
+  MOZ_ASSERT(AndroidBridge::IsJavaUiThread());
+  if (::mozilla::jni::NativeWeakPtr<LayerViewSupport>::Accessor lvs{
+          mLayerViewSupport.Access()}) {
+    lvs->RecvScreenPixels(std::move(aMem), aSize, aNeedsYFlip);
+  }
+}
+
+void nsWindow::UpdateDynamicToolbarMaxHeight(ScreenIntCoord aHeight) {
+  if (mDynamicToolbarMaxHeight == aHeight) {
+    return;
+  }
+
+  mDynamicToolbarMaxHeight = aHeight;
+
+  if (mWidgetListener) {
+    mWidgetListener->DynamicToolbarMaxHeightChanged(aHeight);
+  }
+
+  if (mAttachedWidgetListener) {
+    mAttachedWidgetListener->DynamicToolbarMaxHeightChanged(aHeight);
+  }
+}
+
+void nsWindow::UpdateDynamicToolbarOffset(ScreenIntCoord aOffset) {
+  if (mWidgetListener) {
+    mWidgetListener->DynamicToolbarOffsetChanged(aOffset);
+  }
+
+  if (mAttachedWidgetListener) {
+    mAttachedWidgetListener->DynamicToolbarOffsetChanged(aOffset);
+  }
+}
+
+ScreenIntMargin nsWindow::GetSafeAreaInsets() const { return mSafeAreaInsets; }
+
+void nsWindow::UpdateSafeAreaInsets(const ScreenIntMargin& aSafeAreaInsets) {
+  mSafeAreaInsets = aSafeAreaInsets;
+
+  if (mWidgetListener) {
+    mWidgetListener->SafeAreaInsetsChanged(aSafeAreaInsets);
+  }
+
+  if (mAttachedWidgetListener) {
+    mAttachedWidgetListener->SafeAreaInsetsChanged(aSafeAreaInsets);
+  }
+}
+
+jni::NativeWeakPtr<NPZCSupport> nsWindow::GetNPZCSupportWeakPtr() {
+  return mNPZCSupport;
+}
+
+already_AddRefed<nsIWidget> nsIWidget::CreateTopLevelWindow() {
+  nsCOMPtr<nsIWidget> window = new nsWindow();
+  return window.forget();
+}
+
+already_AddRefed<nsIWidget> nsIWidget::CreateChildWindow() {
+  nsCOMPtr<nsIWidget> window = new nsWindow();
+  return window.forget();
+}
+
+static already_AddRefed<DataSourceSurface> GetCursorImage(
+    const nsIWidget::Cursor& aCursor, mozilla::CSSToLayoutDeviceScale aScale) {
+  if (!aCursor.IsCustom()) {
+    return nullptr;
+  }
+
+  RefPtr<DataSourceSurface> destDataSurface;
+
+  nsIntSize size = nsIWidget::CustomCursorSize(aCursor);
+  // prevent DoS attacks
+  if (size.width > 128 || size.height > 128) {
+    return nullptr;
+  }
+
+  RefPtr<gfx::SourceSurface> surface = aCursor.mContainer->GetFrameAtSize(
+      size * aScale.scale, imgIContainer::FRAME_CURRENT,
+      imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
+  if (NS_WARN_IF(!surface)) {
+    return nullptr;
+  }
+
+  return AndroidWidgetUtils::GetDataSourceSurfaceForAndroidBitmap(surface);
+}
+
+static int32_t GetCursorType(nsCursor aCursor) {
+  // When our minimal requirement of SDK version is 25+,
+  // we should replace with JNI auto-generator.
+  switch (aCursor) {
+    case eCursor_standard:
+      // android.view.PointerIcon.TYPE_ARROW
+      return 0x3e8;
+    case eCursor_wait:
+      // android.view.PointerIcon.TYPE_WAIT
+      return 0x3ec;
+    case eCursor_select:
+      // android.view.PointerIcon.TYPE_TEXT;
+      return 0x3f0;
+    case eCursor_hyperlink:
+      // android.view.PointerIcon.TYPE_HAND
+      return 0x3ea;
+    case eCursor_n_resize:
+    case eCursor_s_resize:
+    case eCursor_ns_resize:
+    case eCursor_row_resize:
+      // android.view.PointerIcon.TYPE_VERTICAL_DOUBLE_ARROW
+      return 0x3f7;
+    case eCursor_w_resize:
+    case eCursor_e_resize:
+    case eCursor_ew_resize:
+    case eCursor_col_resize:
+      // android.view.PointerIcon.TYPE_HORIZONTAL_DOUBLE_ARROW
+      return 0x3f6;
+    case eCursor_nw_resize:
+    case eCursor_se_resize:
+    case eCursor_nwse_resize:
+      // android.view.PointerIcon.TYPE_TOP_LEFT_DIAGONAL_DOUBLE_ARROW
+      return 0x3f9;
+    case eCursor_ne_resize:
+    case eCursor_sw_resize:
+    case eCursor_nesw_resize:
+      // android.view.PointerIcon.TYPE_TOP_RIGHT_DIAGONAL_DOUBLE_ARROW
+      return 0x3f8;
+    case eCursor_crosshair:
+      // android.view.PointerIcon.TYPE_CROSSHAIR
+      return 0x3ef;
+    case eCursor_move:
+      // android.view.PointerIcon.TYPE_ARROW
+      return 0x3e8;
+    case eCursor_help:
+      // android.view.PointerIcon.TYPE_HELP
+      return 0x3eb;
+    case eCursor_copy:
+      // android.view.PointerIcon.TYPE_COPY
+      return 0x3f3;
+    case eCursor_alias:
+      // android.view.PointerIcon.TYPE_ALIAS
+      return 0x3f2;
+    case eCursor_context_menu:
+      // android.view.PointerIcon.TYPE_CONTEXT_MENU
+      return 0x3e9;
+    case eCursor_cell:
+      // android.view.PointerIcon.TYPE_CELL
+      return 0x3ee;
+    case eCursor_grab:
+      // android.view.PointerIcon.TYPE_GRAB
+      return 0x3fc;
+    case eCursor_grabbing:
+      // android.view.PointerIcon.TYPE_GRABBING
+      return 0x3fd;
+    case eCursor_spinning:
+      // android.view.PointerIcon.TYPE_WAIT
+      return 0x3ec;
+    case eCursor_zoom_in:
+      // android.view.PointerIcon.TYPE_ZOOM_IN
+      return 0x3fa;
+    case eCursor_zoom_out:
+      // android.view.PointerIcon.TYPE_ZOOM_OUT
+      return 0x3fb;
+    case eCursor_not_allowed:
+      // android.view.PointerIcon.TYPE_NO_DROP:
+      return 0x3f4;
+    case eCursor_no_drop:
+      // android.view.PointerIcon.TYPE_NO_DROP:
+      return 0x3f4;
+    case eCursor_vertical_text:
+      // android.view.PointerIcon.TYPE_VERTICAL_TEXT
+      return 0x3f1;
+    case eCursor_all_scroll:
+      // android.view.PointerIcon.TYPE_ALL_SCROLL
+      return 0x3f5;
+    case eCursor_none:
+      // android.view.PointerIcon.TYPE_NULL
+      return 0;
+    default:
+      NS_WARNING_ASSERTION(aCursor, "Invalid cursor type");
+      // android.view.PointerIcon.TYPE_ARROW
+      return 0x3e8;
+  }
+}
+
+void nsWindow::SetCursor(const Cursor& aCursor) {
+  if (mozilla::jni::GetAPIVersion() < 24) {
+    return;
+  }
+
+  // Only change cursor if it's actually been changed
+  if (!mUpdateCursor && mCursor == aCursor) {
+    return;
+  }
+
+  mUpdateCursor = false;
+  mCursor = aCursor;
+
+  int32_t type = 0;
+  RefPtr<DataSourceSurface> destDataSurface =
+      GetCursorImage(aCursor, GetDefaultScale());
+  if (!destDataSurface) {
+    type = GetCursorType(aCursor.mDefaultCursor);
+  }
+
+  if (mozilla::jni::NativeWeakPtr<LayerViewSupport>::Accessor lvs{
+          mLayerViewSupport.Access()}) {
+    const auto& compositor = lvs->GetJavaCompositor();
+
+    DispatchToUiThread(
+        "nsWindow::SetCursor",
+        [compositor = GeckoSession::Compositor::GlobalRef(compositor), type,
+         destDataSurface = std::move(destDataSurface),
+         hotspotX = aCursor.mHotspotX, hotspotY = aCursor.mHotspotY] {
+          java::sdk::Bitmap::LocalRef bitmap;
+          if (destDataSurface) {
+            DataSourceSurface::ScopedMap destMap(destDataSurface,
+                                                 DataSourceSurface::READ);
+            auto pixels = mozilla::jni::ByteBuffer::New(
+                reinterpret_cast<int8_t*>(destMap.GetData()),
+                destMap.GetStride() * destDataSurface->GetSize().height);
+            bitmap = java::sdk::Bitmap::CreateBitmap(
+                destDataSurface->GetSize().width,
+                destDataSurface->GetSize().height,
+                java::sdk::Bitmap::Config::ARGB_8888());
+            bitmap->CopyPixelsFromBuffer(pixels);
+          }
+          compositor->SetPointerIcon(type, bitmap, hotspotX, hotspotY);
+        });
+  }
+}
diff --git a/widget/android/nsWindow.h b/widget/android/nsWindow.h
new file mode 100644
index 0000000000..a2c2a798fe
--- /dev/null
+++ b/widget/android/nsWindow.h
@@ -0,0 +1,299 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * vim: set sw=2 ts=4 expandtab:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NSWINDOW_H_
+#define NSWINDOW_H_
+
+#include "AndroidGraphics.h"
+#include "nsBaseWidget.h"
+#include "gfxPoint.h"
+#include "nsIUserIdleServiceInternal.h"
+#include "nsTArray.h"
+#include "EventDispatcher.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/java/GeckoSessionNatives.h"
+#include "mozilla/java/WebResponseWrappers.h"
+#include "mozilla/MozPromise.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/TextRange.h"
+#include "mozilla/UniquePtr.h"
+
+struct ANPEvent;
+
+namespace mozilla {
+class WidgetTouchEvent;
+
+namespace layers {
+class CompositorBridgeChild;
+class LayerManager;
+class APZCTreeManager;
+class UiCompositorControllerChild;
+}  // namespace layers
+
+namespace widget {
+class AndroidView;
+class GeckoEditableSupport;
+class GeckoViewSupport;
+class LayerViewSupport;
+class NPZCSupport;
+class PlatformCompositorWidgetDelegate;
+}  // namespace widget
+
+namespace ipc {
+class Shmem;
+}  // namespace ipc
+
+namespace a11y {
+class SessionAccessibility;
+}  // namespace a11y
+}  // namespace mozilla
+
+class nsWindow final : public nsBaseWidget {
+ private:
+  virtual ~nsWindow();
+
+ public:
+  using nsBaseWidget::GetWindowRenderer;
+
+  nsWindow();
+
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(nsWindow, nsBaseWidget)
+
+  static void InitNatives();
+  void OnGeckoViewReady();
+  RefPtr<mozilla::MozPromise<bool, bool, false>> OnLoadRequest(
+      nsIURI* aUri, int32_t aWindowType, int32_t aFlags,
+      nsIPrincipal* aTriggeringPrincipal, bool aHasUserGesture,
+      bool aIsTopLevel);
+
+  void OnUpdateSessionStore(mozilla::jni::Object::Param aBundle);
+
+ private:
+  // Unique ID given to each widget, used to map Surfaces to widgets
+  // in the CompositorSurfaceManager.
+  int32_t mWidgetId;
+
+ private:
+  RefPtr<mozilla::widget::AndroidView> mAndroidView;
+
+  // Object that implements native LayerView calls.
+  // Owned by the Java Compositor instance.
+  mozilla::jni::NativeWeakPtr<mozilla::widget::LayerViewSupport>
+      mLayerViewSupport;
+
+  // Object that implements native NativePanZoomController calls.
+  // Owned by the Java NativePanZoomController instance.
+  mozilla::jni::NativeWeakPtr<mozilla::widget::NPZCSupport> mNPZCSupport;
+
+  // Object that implements native GeckoEditable calls.
+  // Strong referenced by the Java instance.
+  mozilla::jni::NativeWeakPtr<mozilla::widget::GeckoEditableSupport>
+      mEditableSupport;
+  mozilla::jni::Object::GlobalRef mEditableParent;
+
+  // Object that implements native SessionAccessibility calls.
+  // Strong referenced by the Java instance.
+  mozilla::jni::NativeWeakPtr<mozilla::a11y::SessionAccessibility>
+      mSessionAccessibility;
+
+  // Object that implements native GeckoView calls and associated states.
+  // nullptr for nsWindows that were not opened from GeckoView.
+  mozilla::jni::NativeWeakPtr<mozilla::widget::GeckoViewSupport>
+      mGeckoViewSupport;
+
+  mozilla::Atomic<bool, mozilla::ReleaseAcquire> mContentDocumentDisplayed;
+
+ public:
+  static already_AddRefed<nsWindow> From(nsPIDOMWindowOuter* aDOMWindow);
+  static already_AddRefed<nsWindow> From(nsIWidget* aWidget);
+
+  static nsWindow* TopWindow();
+
+  static mozilla::Modifiers GetModifiers(int32_t aMetaState);
+  static mozilla::TimeStamp GetEventTimeStamp(int64_t aEventTime);
+
+  void InitEvent(mozilla::WidgetGUIEvent& event,
+                 LayoutDeviceIntPoint* aPoint = 0);
+
+  void UpdateOverscrollVelocity(const float aX, const float aY);
+  void UpdateOverscrollOffset(const float aX, const float aY);
+
+  mozilla::widget::EventDispatcher* GetEventDispatcher() const;
+
+  void PassExternalResponse(mozilla::java::WebResponse::Param aResponse);
+
+  void ShowDynamicToolbar();
+
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY void OnDragEvent(
+      int32_t aAction, int64_t aTime, float aX, float aY,
+      mozilla::jni::Object::Param aDropData);
+  void StartDragAndDrop(mozilla::java::sdk::Bitmap::LocalRef aBitmap);
+  void UpdateDragImage(mozilla::java::sdk::Bitmap::LocalRef aBitmap);
+
+  void DetachNatives();
+
+  mozilla::Mutex& GetDestroyMutex() { return mDestroyMutex; }
+
+  //
+  // nsIWidget
+  //
+
+  using nsBaseWidget::Create;  // for Create signature not overridden here
+  [[nodiscard]] virtual nsresult Create(nsIWidget* aParent,
+                                        nsNativeWidget aNativeParent,
+                                        const LayoutDeviceIntRect& aRect,
+                                        InitData* aInitData) override;
+  virtual void Destroy() override;
+  virtual void SetParent(nsIWidget* aNewParent) override;
+  virtual nsIWidget* GetParent(void) override;
+  virtual float GetDPI() override;
+  virtual double GetDefaultScaleInternal() override;
+  virtual void Show(bool aState) override;
+  virtual bool IsVisible() const override;
+  virtual void ConstrainPosition(DesktopIntPoint&) override;
+  virtual void Move(double aX, double aY) override;
+  virtual void Resize(double aWidth, double aHeight, bool aRepaint) override;
+  virtual void Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) override;
+  void SetZIndex(int32_t aZIndex) override;
+  virtual nsSizeMode SizeMode() override { return mSizeMode; }
+  virtual void SetSizeMode(nsSizeMode aMode) override;
+  virtual void Enable(bool aState) override;
+  virtual bool IsEnabled() const override;
+  virtual void Invalidate(const LayoutDeviceIntRect& aRect) override;
+  virtual void SetFocus(Raise, mozilla::dom::CallerType aCallerType) override;
+  virtual LayoutDeviceIntRect GetScreenBounds() override;
+  virtual LayoutDeviceIntPoint WidgetToScreenOffset() override;
+  virtual nsresult DispatchEvent(mozilla::WidgetGUIEvent* aEvent,
+                                 nsEventStatus& aStatus) override;
+  nsEventStatus DispatchEvent(mozilla::WidgetGUIEvent* aEvent);
+  virtual nsresult MakeFullScreen(bool aFullScreen) override;
+  void SetCursor(const Cursor& aDefaultCursor) override;
+  void* GetNativeData(uint32_t aDataType) override;
+  virtual nsresult SetTitle(const nsAString& aTitle) override { return NS_OK; }
+  [[nodiscard]] virtual nsresult GetAttention(int32_t aCycleCount) override {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  TextEventDispatcherListener* GetNativeTextEventDispatcherListener() override;
+  virtual void SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction) override;
+  virtual InputContext GetInputContext() override;
+
+  WindowRenderer* GetWindowRenderer() override;
+
+  void NotifyCompositorSessionLost(
+      mozilla::layers::CompositorSession* aSession) override;
+
+  virtual bool NeedsPaint() override;
+
+  virtual bool WidgetPaintsBackground() override;
+
+  virtual uint32_t GetMaxTouchPoints() const override;
+
+  void UpdateZoomConstraints(
+      const uint32_t& aPresShellId, const ScrollableLayerGuid::ViewID& aViewId,
+      const mozilla::Maybe<ZoomConstraints>& aConstraints) override;
+
+  nsresult SynthesizeNativeTouchPoint(uint32_t aPointerId,
+                                      TouchPointerState aPointerState,
+                                      LayoutDeviceIntPoint aPoint,
+                                      double aPointerPressure,
+                                      uint32_t aPointerOrientation,
+                                      nsIObserver* aObserver) override;
+  nsresult SynthesizeNativeMouseEvent(LayoutDeviceIntPoint aPoint,
+                                      NativeMouseMessage aNativeMessage,
+                                      mozilla::MouseButton aButton,
+                                      nsIWidget::Modifiers aModifierFlags,
+                                      nsIObserver* aObserver) override;
+  nsresult SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
+                                     nsIObserver* aObserver) override;
+
+  void SetCompositorWidgetDelegate(CompositorWidgetDelegate* delegate) override;
+
+  virtual void GetCompositorWidgetInitData(
+      mozilla::widget::CompositorWidgetInitData* aInitData) override;
+
+  mozilla::layers::CompositorBridgeChild* GetCompositorBridgeChild() const;
+
+  void SetContentDocumentDisplayed(bool aDisplayed);
+  bool IsContentDocumentDisplayed();
+
+  // Call this function when the users activity is the direct cause of an
+  // event (like a keypress or mouse click).
+  void UserActivity();
+
+  mozilla::jni::Object::Ref& GetEditableParent() { return mEditableParent; }
+
+  RefPtr<mozilla::a11y::SessionAccessibility> GetSessionAccessibility();
+
+  void RecvToolbarAnimatorMessageFromCompositor(int32_t aMessage) override;
+  void UpdateRootFrameMetrics(const ScreenPoint& aScrollOffset,
+                              const CSSToScreenScale& aZoom) override;
+  void RecvScreenPixels(mozilla::ipc::Shmem&& aMem, const ScreenIntSize& aSize,
+                        bool aNeedsYFlip) override;
+  void UpdateDynamicToolbarMaxHeight(mozilla::ScreenIntCoord aHeight) override;
+  mozilla::ScreenIntCoord GetDynamicToolbarMaxHeight() const override {
+    return mDynamicToolbarMaxHeight;
+  }
+
+  void UpdateDynamicToolbarOffset(mozilla::ScreenIntCoord aOffset);
+
+  virtual mozilla::ScreenIntMargin GetSafeAreaInsets() const override;
+  void UpdateSafeAreaInsets(const mozilla::ScreenIntMargin& aSafeAreaInsets);
+
+  mozilla::jni::NativeWeakPtr<mozilla::widget::NPZCSupport>
+  GetNPZCSupportWeakPtr();
+
+ protected:
+  void BringToFront();
+  nsWindow* FindTopLevel();
+  bool IsTopLevel();
+
+  void ConfigureAPZControllerThread() override;
+  void DispatchHitTest(const mozilla::WidgetTouchEvent& aEvent);
+
+  already_AddRefed<GeckoContentController> CreateRootContentController()
+      override;
+
+  bool mIsVisible;
+  nsTArray<nsWindow*> mChildren;
+  nsWindow* mParent;
+
+  nsCOMPtr<nsIUserIdleServiceInternal> mIdleService;
+  mozilla::ScreenIntCoord mDynamicToolbarMaxHeight;
+  mozilla::ScreenIntMargin mSafeAreaInsets;
+
+  nsSizeMode mSizeMode;
+  bool mIsFullScreen;
+
+  bool UseExternalCompositingSurface() const override { return true; }
+
+  static void DumpWindows();
+  static void DumpWindows(const nsTArray<nsWindow*>& wins, int indent = 0);
+  static void LogWindow(nsWindow* win, int index, int indent);
+
+ private:
+  void CreateLayerManager();
+  void RedrawAll();
+
+  void OnSizeChanged(const mozilla::gfx::IntSize& aSize);
+
+  mozilla::layers::LayersId GetRootLayerId() const;
+  RefPtr<mozilla::layers::UiCompositorControllerChild>
+  GetUiCompositorControllerChild();
+
+  mozilla::widget::PlatformCompositorWidgetDelegate* mCompositorWidgetDelegate;
+
+  mozilla::Mutex mDestroyMutex;
+
+  friend class mozilla::widget::GeckoViewSupport;
+  friend class mozilla::widget::LayerViewSupport;
+  friend class mozilla::widget::NPZCSupport;
+};
+
+#endif /* NSWINDOW_H_ */
diff --git a/widget/cocoa/AppearanceOverride.h b/widget/cocoa/AppearanceOverride.h
new file mode 100644
index 0000000000..c4ae629320
--- /dev/null
+++ b/widget/cocoa/AppearanceOverride.h
@@ -0,0 +1,19 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef AppearanceOverride_h
+#define AppearanceOverride_h
+
+#import <Cocoa/Cocoa.h>
+
+// Implements support for the browser.theme.toolbar-theme pref.
+// Use MOZGlobalAppearance.sharedInstance.effectiveAppearance
+// in all places where you would like the global override to be respected. The
+// effectiveAppearance property can be key-value observed.
+@interface MOZGlobalAppearance : NSObject <NSAppearanceCustomization>
+@property(class, readonly) MOZGlobalAppearance* sharedInstance;
+@end
+
+#endif
diff --git a/widget/cocoa/AppearanceOverride.mm b/widget/cocoa/AppearanceOverride.mm
new file mode 100644
index 0000000000..c3938d6b93
--- /dev/null
+++ b/widget/cocoa/AppearanceOverride.mm
@@ -0,0 +1,90 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "AppearanceOverride.h"
+
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/StaticPrefs_widget.h"
+
+#include "nsXULAppAPI.h"
+
+static void ToolbarThemePrefChanged(const char* aPref, void* aUserInfo);
+
+@interface MOZGlobalAppearance ()
+@property NSInteger toolbarTheme;
+@end
+
+@implementation MOZGlobalAppearance
+
++ (MOZGlobalAppearance*)sharedInstance {
+  static MOZGlobalAppearance* sInstance = nil;
+  if (!sInstance) {
+    sInstance = [[MOZGlobalAppearance alloc] init];
+    if (XRE_IsParentProcess()) {
+      mozilla::Preferences::RegisterCallbackAndCall(
+          &ToolbarThemePrefChanged,
+          nsDependentCString(
+              mozilla::StaticPrefs::GetPrefName_browser_theme_toolbar_theme()));
+    }
+  }
+  return sInstance;
+}
+
++ (NSSet*)keyPathsForValuesAffectingAppearance {
+  return [NSSet setWithObjects:@"toolbarTheme", nil];
+}
+
+- (NSAppearance*)appearance {
+  switch (self.toolbarTheme) {  // Value for browser.theme.toolbar-theme pref
+    case 0:                     // Dark
+      return [NSAppearance appearanceNamed:NSAppearanceNameDarkAqua];
+    case 1:  // Light
+      return [NSAppearance appearanceNamed:NSAppearanceNameAqua];
+    case 2:  // System
+    default:
+      return nil;  // nil means "no override".
+  }
+}
+
+- (void)setAppearance:(NSAppearance*)aAppearance {
+  // ignored
+}
+
+- (NSApplication*)_app {
+  return NSApp;
+}
+
++ (NSSet*)keyPathsForValuesAffectingEffectiveAppearance {
+  // Automatically notify any key-value observers of our effectiveAppearance
+  // property whenever the pref or the NSApp's effectiveAppearance change.
+  return
+      [NSSet setWithObjects:@"toolbarTheme", @"_app.effectiveAppearance", nil];
+}
+
+- (NSAppearance*)effectiveAppearance {
+  switch (self.toolbarTheme) {  // Value for browser.theme.toolbar-theme pref
+    case 0:                     // Dark
+      return [NSAppearance appearanceNamed:NSAppearanceNameDarkAqua];
+    case 1:  // Light
+      return [NSAppearance appearanceNamed:NSAppearanceNameAqua];
+    case 2:  // System
+    default:
+      // Use the NSApp effectiveAppearance. This is the system appearance.
+      return NSApp.effectiveAppearance;
+  }
+}
+
+@end
+
+static void ToolbarThemePrefChanged(const char* aPref, void* aUserInfo) {
+  MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+
+  MOZGlobalAppearance.sharedInstance.toolbarTheme =
+      mozilla::StaticPrefs::browser_theme_toolbar_theme();
+}
diff --git a/widget/cocoa/CFTypeRefPtr.h b/widget/cocoa/CFTypeRefPtr.h
new file mode 100644
index 0000000000..185355777e
--- /dev/null
+++ b/widget/cocoa/CFTypeRefPtr.h
@@ -0,0 +1,194 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef CFTypeRefPtr_h
+#define CFTypeRefPtr_h
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/DbgMacro.h"
+#include "mozilla/HashFunctions.h"
+
+// A smart pointer for CoreFoundation classes which does reference counting.
+//
+// Manual reference counting:
+//
+// UInt32 someNumber = 10;
+// CFNumberRef numberObject =
+//     CFNumberCreate(kCFAllocatorDefault, kCFNumberIntType, &someNumber);
+// // do something with numberObject
+// CFRelease(numberObject);
+//
+// Automatic reference counting using CFTypeRefPtr:
+//
+// UInt32 someNumber = 10;
+// auto numberObject =
+//      CFTypeRefPtr<CFNumberRef>::WrapUnderCreateRule(
+//        CFNumberCreate(kCFAllocatorDefault, kCFNumberIntType, &someNumber));
+// // do something with numberObject
+// // no CFRelease
+
+template <class PtrT>
+class CFTypeRefPtr {
+ private:
+  void assign_with_CFRetain(PtrT aRawPtr) {
+    CFRetain(aRawPtr);
+    assign_assuming_CFRetain(aRawPtr);
+  }
+
+  void assign_assuming_CFRetain(PtrT aNewPtr) {
+    PtrT oldPtr = mRawPtr;
+    mRawPtr = aNewPtr;
+    if (oldPtr) {
+      CFRelease(oldPtr);
+    }
+  }
+
+ private:
+  PtrT mRawPtr;
+
+ public:
+  ~CFTypeRefPtr() {
+    if (mRawPtr) {
+      CFRelease(mRawPtr);
+    }
+  }
+
+  // Constructors
+
+  CFTypeRefPtr() : mRawPtr(nullptr) {}
+
+  CFTypeRefPtr(const CFTypeRefPtr<PtrT>& aSmartPtr)
+      : mRawPtr(aSmartPtr.mRawPtr) {
+    if (mRawPtr) {
+      CFRetain(mRawPtr);
+    }
+  }
+
+  CFTypeRefPtr(CFTypeRefPtr<PtrT>&& aRefPtr) : mRawPtr(aRefPtr.mRawPtr) {
+    aRefPtr.mRawPtr = nullptr;
+  }
+
+  MOZ_IMPLICIT CFTypeRefPtr(decltype(nullptr)) : mRawPtr(nullptr) {}
+
+  // There is no constructor from a raw pointer value.
+  // Use one of the static WrapUnder*Rule methods below instead.
+
+  static CFTypeRefPtr<PtrT> WrapUnderCreateRule(PtrT aRawPtr) {
+    CFTypeRefPtr<PtrT> ptr;
+    ptr.AssignUnderCreateRule(aRawPtr);
+    return ptr;
+  }
+
+  static CFTypeRefPtr<PtrT> WrapUnderGetRule(PtrT aRawPtr) {
+    CFTypeRefPtr<PtrT> ptr;
+    ptr.AssignUnderGetRule(aRawPtr);
+    return ptr;
+  }
+
+  // Assignment operators
+
+  CFTypeRefPtr<PtrT>& operator=(decltype(nullptr)) {
+    assign_assuming_CFRetain(nullptr);
+    return *this;
+  }
+
+  CFTypeRefPtr<PtrT>& operator=(const CFTypeRefPtr<PtrT>& aRhs) {
+    assign_with_CFRetain(aRhs.mRawPtr);
+    return *this;
+  }
+
+  CFTypeRefPtr<PtrT>& operator=(CFTypeRefPtr<PtrT>&& aRefPtr) {
+    assign_assuming_CFRetain(aRefPtr.mRawPtr);
+    aRefPtr.mRawPtr = nullptr;
+    return *this;
+  }
+
+  // There is no operator= for a raw pointer value.
+  // Use one of the AssignUnder*Rule methods below instead.
+
+  CFTypeRefPtr<PtrT>& AssignUnderCreateRule(PtrT aRawPtr) {
+    // Freshly-created objects come with a retain count of 1.
+    assign_assuming_CFRetain(aRawPtr);
+    return *this;
+  }
+
+  CFTypeRefPtr<PtrT>& AssignUnderGetRule(PtrT aRawPtr) {
+    assign_with_CFRetain(aRawPtr);
+    return *this;
+  }
+
+  // Other pointer operators
+
+  // This is the only way to get the raw pointer out of the smart pointer.
+  // There is no implicit conversion to a raw pointer.
+  PtrT get() const { return mRawPtr; }
+
+  // Don't allow implicit conversion of temporary CFTypeRefPtr to raw pointer,
+  // because the refcount might be one and the pointer will immediately become
+  // invalid.
+  operator PtrT() const&& = delete;
+  // Also don't allow implicit conversion of non-temporary CFTypeRefPtr.
+  operator PtrT() const& = delete;
+
+  // These let you null-check a pointer without calling get().
+  explicit operator bool() const { return !!mRawPtr; }
+};
+
+template <class PtrT>
+inline bool operator==(const CFTypeRefPtr<PtrT>& aLhs,
+                       const CFTypeRefPtr<PtrT>& aRhs) {
+  return aLhs.get() == aRhs.get();
+}
+
+template <class PtrT>
+inline bool operator!=(const CFTypeRefPtr<PtrT>& aLhs,
+                       const CFTypeRefPtr<PtrT>& aRhs) {
+  return !(aLhs == aRhs);
+}
+
+// Comparing an |CFTypeRefPtr| to |nullptr|
+
+template <class PtrT>
+inline bool operator==(const CFTypeRefPtr<PtrT>& aLhs, decltype(nullptr)) {
+  return aLhs.get() == nullptr;
+}
+
+template <class PtrT>
+inline bool operator==(decltype(nullptr), const CFTypeRefPtr<PtrT>& aRhs) {
+  return nullptr == aRhs.get();
+}
+
+template <class PtrT>
+inline bool operator!=(const CFTypeRefPtr<PtrT>& aLhs, decltype(nullptr)) {
+  return aLhs.get() != nullptr;
+}
+
+template <class PtrT>
+inline bool operator!=(decltype(nullptr), const CFTypeRefPtr<PtrT>& aRhs) {
+  return nullptr != aRhs.get();
+}
+
+// MOZ_DBG support
+
+template <class PtrT>
+std::ostream& operator<<(std::ostream& aOut, const CFTypeRefPtr<PtrT>& aObj) {
+  return mozilla::DebugValue(aOut, aObj.get());
+}
+
+// std::hash support (e.g. for unordered_map)
+namespace std {
+template <class PtrT>
+struct hash<CFTypeRefPtr<PtrT>> {
+  typedef CFTypeRefPtr<PtrT> argument_type;
+  typedef std::size_t result_type;
+  result_type operator()(argument_type const& aPtr) const {
+    return mozilla::HashGeneric(reinterpret_cast<uintptr_t>(aPtr.get()));
+  }
+};
+}  // namespace std
+
+#endif /* CFTypeRefPtr_h */
diff --git a/widget/cocoa/CustomCocoaEvents.h b/widget/cocoa/CustomCocoaEvents.h
new file mode 100644
index 0000000000..3c02feb4b0
--- /dev/null
+++ b/widget/cocoa/CustomCocoaEvents.h
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * This file defines constants to be used in the "subtype" field of
+ * NSEventTypeApplicationDefined type NSEvents.
+ */
+
+#ifndef WIDGET_COCOA_CUSTOMCOCOAEVENTS_H_
+#define WIDGET_COCOA_CUSTOMCOCOAEVENTS_H_
+
+// Empty event, just used for prodding the event loop into responding.
+const short kEventSubtypeNone = 0;
+// Tracer event, used for timing the event loop responsiveness.
+const short kEventSubtypeTrace = 1;
+
+#endif /* WIDGET_COCOA_CUSTOMCOCOAEVENTS_H_ */
diff --git a/widget/cocoa/DesktopBackgroundImage.h b/widget/cocoa/DesktopBackgroundImage.h
new file mode 100644
index 0000000000..2fd7565369
--- /dev/null
+++ b/widget/cocoa/DesktopBackgroundImage.h
@@ -0,0 +1,19 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_COCOA_DESKTOPBACKGROUNDIMAGE_H_
+#define WIDGET_COCOA_DESKTOPBACKGROUNDIMAGE_H_
+
+class nsIFile;
+
+namespace mozilla {
+namespace widget {
+
+void SetDesktopImage(nsIFile* aImage);
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // WIDGET_COCOA_DESKTOPBACKGROUNDIMAGE_H_
diff --git a/widget/cocoa/DesktopBackgroundImage.mm b/widget/cocoa/DesktopBackgroundImage.mm
new file mode 100644
index 0000000000..7c00109db5
--- /dev/null
+++ b/widget/cocoa/DesktopBackgroundImage.mm
@@ -0,0 +1,69 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Logging.h"
+#include "nsCocoaUtils.h"
+#include "nsIFile.h"
+#include "DesktopBackgroundImage.h"
+
+#import <Foundation/Foundation.h>
+
+extern mozilla::LazyLogModule gCocoaUtilsLog;
+#undef LOG
+#define LOG(...) MOZ_LOG(gCocoaUtilsLog, LogLevel::Debug, (__VA_ARGS__))
+
+namespace mozilla {
+namespace widget {
+
+void SetDesktopImage(nsIFile* aImage) {
+  nsAutoCString imagePath;
+  nsresult rv = aImage->GetNativePath(imagePath);
+  if (NS_FAILED(rv)) {
+    LOG("%s ERROR: failed to get image path", __func__);
+    return;
+  }
+
+  bool exists = false;
+  rv = aImage->Exists(&exists);
+  if (NS_FAILED(rv) || !exists) {
+    LOG("%s ERROR: file \"%s\" does not exist", __func__, imagePath.get());
+    return;
+  }
+
+  NSString* urlString = [NSString stringWithUTF8String:imagePath.get()];
+  if (!urlString) {
+    LOG("%s ERROR: null image path \"%s\"", __func__, imagePath.get());
+    return;
+  }
+
+  NSURL* url = [NSURL fileURLWithPath:urlString];
+  if (!url) {
+    LOG("%s ERROR: null image path URL \"%s\"", __func__, imagePath.get());
+    return;
+  }
+
+  // Only apply the background to the screen with focus
+  NSScreen* currentScreen = [NSScreen mainScreen];
+  if (!currentScreen) {
+    LOG("%s ERROR: got null NSScreen", __func__);
+    return;
+  }
+
+  // Use existing options for this screen
+  NSDictionary* screenOptions = [[NSWorkspace sharedWorkspace]
+      desktopImageOptionsForScreen:currentScreen];
+
+  NSError* error = nil;
+  if (![[NSWorkspace sharedWorkspace] setDesktopImageURL:url
+                                               forScreen:currentScreen
+                                                 options:screenOptions
+                                                   error:&error]) {
+    LOG("%s ERROR: setDesktopImageURL failed (%ld)", __func__,
+        (long)[error code]);
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/cocoa/GfxInfo.h b/widget/cocoa/GfxInfo.h
new file mode 100644
index 0000000000..0c6e50c04c
--- /dev/null
+++ b/widget/cocoa/GfxInfo.h
@@ -0,0 +1,98 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_GfxInfo_h__
+#define __mozilla_widget_GfxInfo_h__
+
+#include "GfxInfoBase.h"
+
+#include "nsString.h"
+
+namespace mozilla {
+namespace widget {
+
+class GfxInfo : public GfxInfoBase {
+ public:
+  GfxInfo();
+  // We only declare the subset of nsIGfxInfo that we actually implement. The
+  // rest is brought forward from GfxInfoBase.
+  NS_IMETHOD GetD2DEnabled(bool* aD2DEnabled) override;
+  NS_IMETHOD GetDWriteEnabled(bool* aDWriteEnabled) override;
+  NS_IMETHOD GetDWriteVersion(nsAString& aDwriteVersion) override;
+  NS_IMETHOD GetEmbeddedInFirefoxReality(
+      bool* aEmbeddedInFirefoxReality) override;
+  NS_IMETHOD GetHasBattery(bool* aHasBattery) override;
+  NS_IMETHOD GetWindowProtocol(nsAString& aWindowProtocol) override;
+  NS_IMETHOD GetTestType(nsAString& aTestType) override;
+  NS_IMETHOD GetCleartypeParameters(nsAString& aCleartypeParams) override;
+  NS_IMETHOD GetAdapterDescription(nsAString& aAdapterDescription) override;
+  NS_IMETHOD GetAdapterDriver(nsAString& aAdapterDriver) override;
+  NS_IMETHOD GetAdapterVendorID(nsAString& aAdapterVendorID) override;
+  NS_IMETHOD GetAdapterDeviceID(nsAString& aAdapterDeviceID) override;
+  NS_IMETHOD GetAdapterSubsysID(nsAString& aAdapterSubsysID) override;
+  NS_IMETHOD GetAdapterRAM(uint32_t* aAdapterRAM) override;
+  NS_IMETHOD GetAdapterDriverVendor(nsAString& aAdapterDriverVendor) override;
+  NS_IMETHOD GetAdapterDriverVersion(nsAString& aAdapterDriverVersion) override;
+  NS_IMETHOD GetAdapterDriverDate(nsAString& aAdapterDriverDate) override;
+  NS_IMETHOD GetAdapterDescription2(nsAString& aAdapterDescription) override;
+  NS_IMETHOD GetAdapterDriver2(nsAString& aAdapterDriver) override;
+  NS_IMETHOD GetAdapterVendorID2(nsAString& aAdapterVendorID) override;
+  NS_IMETHOD GetAdapterDeviceID2(nsAString& aAdapterDeviceID) override;
+  NS_IMETHOD GetAdapterSubsysID2(nsAString& aAdapterSubsysID) override;
+  NS_IMETHOD GetAdapterRAM2(uint32_t* aAdapterRAM) override;
+  NS_IMETHOD GetAdapterDriverVendor2(nsAString& aAdapterDriverVendor) override;
+  NS_IMETHOD GetAdapterDriverVersion2(
+      nsAString& aAdapterDriverVersion) override;
+  NS_IMETHOD GetAdapterDriverDate2(nsAString& aAdapterDriverDate) override;
+  NS_IMETHOD GetIsGPU2Active(bool* aIsGPU2Active) override;
+  NS_IMETHOD GetDrmRenderDevice(nsACString& aDrmRenderDevice) override;
+
+  using GfxInfoBase::GetFeatureStatus;
+  using GfxInfoBase::GetFeatureSuggestedDriverVersion;
+
+  virtual nsresult Init() override;
+
+#ifdef DEBUG
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIGFXINFODEBUG
+#endif
+
+  virtual uint32_t OperatingSystemVersion() override { return mOSXVersion; }
+
+ protected:
+  virtual ~GfxInfo() {}
+
+  OperatingSystem GetOperatingSystem() override;
+  virtual nsresult GetFeatureStatusImpl(
+      int32_t aFeature, int32_t* aStatus, nsAString& aSuggestedDriverVersion,
+      const nsTArray<GfxDriverInfo>& aDriverInfo, nsACString& aFailureId,
+      OperatingSystem* aOS = nullptr) override;
+  virtual const nsTArray<GfxDriverInfo>& GetGfxDriverInfo() override;
+
+ private:
+  void GetDeviceInfo();
+  void GetSelectedCityInfo();
+  void AddCrashReportAnnotations();
+
+  uint32_t mNumGPUsDetected;
+
+  uint32_t mAdapterRAM[2];
+  nsString mDeviceID[2];
+  nsString mDriverVersion[2];
+  nsString mDriverDate[2];
+  nsString mDeviceKey[2];
+
+  nsString mAdapterVendorID[2];
+  nsString mAdapterDeviceID[2];
+
+  uint32_t mOSXVersion;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __mozilla_widget_GfxInfo_h__ */
diff --git a/widget/cocoa/GfxInfo.mm b/widget/cocoa/GfxInfo.mm
new file mode 100644
index 0000000000..1476cc27db
--- /dev/null
+++ b/widget/cocoa/GfxInfo.mm
@@ -0,0 +1,562 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <OpenGL/OpenGL.h>
+#include <OpenGL/CGLRenderers.h>
+
+#include "mozilla/ArrayUtils.h"
+
+#include "GfxInfo.h"
+#include "nsUnicharUtils.h"
+#include "nsExceptionHandler.h"
+#include "nsCocoaFeatures.h"
+#include "nsCocoaUtils.h"
+#include "mozilla/Preferences.h"
+#include "js/PropertyAndElement.h"  // JS_SetElement, JS_SetProperty
+
+#include <algorithm>
+
+#import <Foundation/Foundation.h>
+#import <IOKit/IOKitLib.h>
+#import <Cocoa/Cocoa.h>
+
+#include "jsapi.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+#ifdef DEBUG
+NS_IMPL_ISUPPORTS_INHERITED(GfxInfo, GfxInfoBase, nsIGfxInfoDebug)
+#endif
+
+GfxInfo::GfxInfo() : mNumGPUsDetected(0), mOSXVersion{0} {
+  mAdapterRAM[0] = mAdapterRAM[1] = 0;
+}
+
+static OperatingSystem OSXVersionToOperatingSystem(uint32_t aOSXVersion) {
+  switch (nsCocoaFeatures::ExtractMajorVersion(aOSXVersion)) {
+    case 10:
+      switch (nsCocoaFeatures::ExtractMinorVersion(aOSXVersion)) {
+        case 6:
+          return OperatingSystem::OSX10_6;
+        case 7:
+          return OperatingSystem::OSX10_7;
+        case 8:
+          return OperatingSystem::OSX10_8;
+        case 9:
+          return OperatingSystem::OSX10_9;
+        case 10:
+          return OperatingSystem::OSX10_10;
+        case 11:
+          return OperatingSystem::OSX10_11;
+        case 12:
+          return OperatingSystem::OSX10_12;
+        case 13:
+          return OperatingSystem::OSX10_13;
+        case 14:
+          return OperatingSystem::OSX10_14;
+        case 15:
+          return OperatingSystem::OSX10_15;
+        case 16:
+          // Depending on the SDK version, we either get 10.16 or 11.0.
+          // Normalize this to 11.0.
+          return OperatingSystem::OSX11_0;
+        default:
+          break;
+      }
+      break;
+    case 11:
+      switch (nsCocoaFeatures::ExtractMinorVersion(aOSXVersion)) {
+        case 0:
+          return OperatingSystem::OSX11_0;
+        default:
+          break;
+      }
+      break;
+  }
+
+  return OperatingSystem::Unknown;
+}
+// The following three functions are derived from Chromium code
+static CFTypeRef SearchPortForProperty(io_registry_entry_t dspPort,
+                                       CFStringRef propertyName) {
+  return IORegistryEntrySearchCFProperty(
+      dspPort, kIOServicePlane, propertyName, kCFAllocatorDefault,
+      kIORegistryIterateRecursively | kIORegistryIterateParents);
+}
+
+static uint32_t IntValueOfCFData(CFDataRef d) {
+  uint32_t value = 0;
+
+  if (d) {
+    const uint32_t* vp = reinterpret_cast<const uint32_t*>(CFDataGetBytePtr(d));
+    if (vp != NULL) value = *vp;
+  }
+
+  return value;
+}
+
+void GfxInfo::GetDeviceInfo() {
+  mNumGPUsDetected = 0;
+
+  CFMutableDictionaryRef pci_dev_dict = IOServiceMatching("IOPCIDevice");
+  io_iterator_t io_iter;
+  if (IOServiceGetMatchingServices(kIOMasterPortDefault, pci_dev_dict,
+                                   &io_iter) != kIOReturnSuccess) {
+    MOZ_DIAGNOSTIC_ASSERT(
+        false,
+        "Failed to detect any GPUs (couldn't enumerate IOPCIDevice services)");
+    return;
+  }
+
+  io_registry_entry_t entry = IO_OBJECT_NULL;
+  while ((entry = IOIteratorNext(io_iter)) != IO_OBJECT_NULL) {
+    constexpr uint32_t kClassCodeDisplayVGA = 0x30000;
+    CFTypeRef class_code_ref =
+        SearchPortForProperty(entry, CFSTR("class-code"));
+    if (class_code_ref) {
+      const uint32_t class_code = IntValueOfCFData((CFDataRef)class_code_ref);
+      CFRelease(class_code_ref);
+
+      if (class_code == kClassCodeDisplayVGA) {
+        CFTypeRef vendor_id_ref =
+            SearchPortForProperty(entry, CFSTR("vendor-id"));
+        if (vendor_id_ref) {
+          mAdapterVendorID[mNumGPUsDetected].AppendPrintf(
+              "0x%04x", IntValueOfCFData((CFDataRef)vendor_id_ref));
+          CFRelease(vendor_id_ref);
+        }
+        CFTypeRef device_id_ref =
+            SearchPortForProperty(entry, CFSTR("device-id"));
+        if (device_id_ref) {
+          mAdapterDeviceID[mNumGPUsDetected].AppendPrintf(
+              "0x%04x", IntValueOfCFData((CFDataRef)device_id_ref));
+          CFRelease(device_id_ref);
+        }
+        ++mNumGPUsDetected;
+      }
+    }
+    IOObjectRelease(entry);
+    if (mNumGPUsDetected == 2) {
+      break;
+    }
+  }
+  IOObjectRelease(io_iter);
+
+  // If we found IOPCI VGA devices, don't look for other devices
+  if (mNumGPUsDetected > 0) {
+    return;
+  }
+
+#if defined(__aarch64__)
+  CFMutableDictionaryRef agx_dev_dict = IOServiceMatching("AGXAccelerator");
+  if (IOServiceGetMatchingServices(kIOMasterPortDefault, agx_dev_dict,
+                                   &io_iter) == kIOReturnSuccess) {
+    io_registry_entry_t entry = IO_OBJECT_NULL;
+    while ((entry = IOIteratorNext(io_iter)) != IO_OBJECT_NULL) {
+      CFTypeRef vendor_id_ref =
+          SearchPortForProperty(entry, CFSTR("vendor-id"));
+      if (vendor_id_ref) {
+        mAdapterVendorID[mNumGPUsDetected].AppendPrintf(
+            "0x%04x", IntValueOfCFData((CFDataRef)vendor_id_ref));
+        CFRelease(vendor_id_ref);
+        ++mNumGPUsDetected;
+      }
+      IOObjectRelease(entry);
+    }
+
+    IOObjectRelease(io_iter);
+  }
+
+  // If we found an AGXAccelerator, don't look for an AppleParavirtGPU
+  if (mNumGPUsDetected > 0) {
+    return;
+  }
+#endif
+
+  CFMutableDictionaryRef apv_dev_dict = IOServiceMatching("AppleParavirtGPU");
+  if (IOServiceGetMatchingServices(kIOMasterPortDefault, apv_dev_dict,
+                                   &io_iter) == kIOReturnSuccess) {
+    io_registry_entry_t entry = IO_OBJECT_NULL;
+    while ((entry = IOIteratorNext(io_iter)) != IO_OBJECT_NULL) {
+      CFTypeRef vendor_id_ref =
+          SearchPortForProperty(entry, CFSTR("vendor-id"));
+      if (vendor_id_ref) {
+        mAdapterVendorID[mNumGPUsDetected].AppendPrintf(
+            "0x%04x", IntValueOfCFData((CFDataRef)vendor_id_ref));
+        CFRelease(vendor_id_ref);
+      }
+
+      CFTypeRef device_id_ref =
+          SearchPortForProperty(entry, CFSTR("device-id"));
+      if (device_id_ref) {
+        mAdapterDeviceID[mNumGPUsDetected].AppendPrintf(
+            "0x%04x", IntValueOfCFData((CFDataRef)device_id_ref));
+        CFRelease(device_id_ref);
+      }
+      ++mNumGPUsDetected;
+      IOObjectRelease(entry);
+    }
+
+    IOObjectRelease(io_iter);
+  }
+
+  MOZ_DIAGNOSTIC_ASSERT(mNumGPUsDetected > 0, "Failed to detect any GPUs");
+}
+
+nsresult GfxInfo::Init() {
+  nsresult rv = GfxInfoBase::Init();
+
+  // Calling CGLQueryRendererInfo causes us to switch to the discrete GPU
+  // even when we don't want to. We'll avoid doing so for now and just
+  // use the device ids.
+
+  GetDeviceInfo();
+
+  AddCrashReportAnnotations();
+
+  mOSXVersion = nsCocoaFeatures::macOSVersion();
+
+  return rv;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetD2DEnabled(bool* aEnabled) { return NS_ERROR_FAILURE; }
+
+NS_IMETHODIMP
+GfxInfo::GetDWriteEnabled(bool* aEnabled) { return NS_ERROR_FAILURE; }
+
+/* readonly attribute bool HasBattery; */
+NS_IMETHODIMP GfxInfo::GetHasBattery(bool* aHasBattery) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+/* readonly attribute DOMString DWriteVersion; */
+NS_IMETHODIMP
+GfxInfo::GetDWriteVersion(nsAString& aDwriteVersion) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetEmbeddedInFirefoxReality(bool* aEmbeddedInFirefoxReality) {
+  return NS_ERROR_FAILURE;
+}
+
+/* readonly attribute DOMString cleartypeParameters; */
+NS_IMETHODIMP
+GfxInfo::GetCleartypeParameters(nsAString& aCleartypeParams) {
+  return NS_ERROR_FAILURE;
+}
+
+/* readonly attribute DOMString windowProtocol; */
+NS_IMETHODIMP
+GfxInfo::GetWindowProtocol(nsAString& aWindowProtocol) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+/* readonly attribute DOMString testType; */
+NS_IMETHODIMP
+GfxInfo::GetTestType(nsAString& aTestType) { return NS_ERROR_NOT_IMPLEMENTED; }
+
+/* readonly attribute DOMString adapterDescription; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDescription(nsAString& aAdapterDescription) {
+  aAdapterDescription.AssignLiteral("");
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterDescription2; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDescription2(nsAString& aAdapterDescription) {
+  if (mNumGPUsDetected < 2) {
+    return NS_ERROR_FAILURE;
+  }
+  aAdapterDescription.AssignLiteral("");
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterRAM; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterRAM(uint32_t* aAdapterRAM) {
+  *aAdapterRAM = mAdapterRAM[0];
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterRAM2; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterRAM2(uint32_t* aAdapterRAM) {
+  if (mNumGPUsDetected < 2) {
+    return NS_ERROR_FAILURE;
+  }
+  *aAdapterRAM = mAdapterRAM[1];
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterDriver; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriver(nsAString& aAdapterDriver) {
+  aAdapterDriver.AssignLiteral("");
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterDriver2; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriver2(nsAString& aAdapterDriver) {
+  if (mNumGPUsDetected < 2) {
+    return NS_ERROR_FAILURE;
+  }
+  aAdapterDriver.AssignLiteral("");
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterDriverVendor; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVendor(nsAString& aAdapterDriverVendor) {
+  aAdapterDriverVendor.AssignLiteral("");
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterDriverVendor2; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVendor2(nsAString& aAdapterDriverVendor) {
+  if (mNumGPUsDetected < 2) {
+    return NS_ERROR_FAILURE;
+  }
+  aAdapterDriverVendor.AssignLiteral("");
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterDriverVersion; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVersion(nsAString& aAdapterDriverVersion) {
+  aAdapterDriverVersion.AssignLiteral("");
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterDriverVersion2; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVersion2(nsAString& aAdapterDriverVersion) {
+  if (mNumGPUsDetected < 2) {
+    return NS_ERROR_FAILURE;
+  }
+  aAdapterDriverVersion.AssignLiteral("");
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterDriverDate; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverDate(nsAString& aAdapterDriverDate) {
+  aAdapterDriverDate.AssignLiteral("");
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterDriverDate2; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverDate2(nsAString& aAdapterDriverDate) {
+  if (mNumGPUsDetected < 2) {
+    return NS_ERROR_FAILURE;
+  }
+  aAdapterDriverDate.AssignLiteral("");
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterVendorID; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterVendorID(nsAString& aAdapterVendorID) {
+  aAdapterVendorID = mAdapterVendorID[0];
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterVendorID2; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterVendorID2(nsAString& aAdapterVendorID) {
+  if (mNumGPUsDetected < 2) {
+    return NS_ERROR_FAILURE;
+  }
+  aAdapterVendorID = mAdapterVendorID[1];
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterDeviceID; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDeviceID(nsAString& aAdapterDeviceID) {
+  aAdapterDeviceID = mAdapterDeviceID[0];
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterDeviceID2; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterDeviceID2(nsAString& aAdapterDeviceID) {
+  if (mNumGPUsDetected < 2) {
+    return NS_ERROR_FAILURE;
+  }
+  aAdapterDeviceID = mAdapterDeviceID[1];
+  return NS_OK;
+}
+
+/* readonly attribute DOMString adapterSubsysID; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterSubsysID(nsAString& aAdapterSubsysID) {
+  return NS_ERROR_FAILURE;
+}
+
+/* readonly attribute DOMString adapterSubsysID2; */
+NS_IMETHODIMP
+GfxInfo::GetAdapterSubsysID2(nsAString& aAdapterSubsysID) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetDrmRenderDevice(nsACString& aDrmRenderDevice) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+/* readonly attribute boolean isGPU2Active; */
+NS_IMETHODIMP
+GfxInfo::GetIsGPU2Active(bool* aIsGPU2Active) { return NS_ERROR_FAILURE; }
+
+void GfxInfo::AddCrashReportAnnotations() {
+  nsString deviceID, vendorID, driverVersion;
+  nsAutoCString narrowDeviceID, narrowVendorID, narrowDriverVersion;
+
+  GetAdapterDeviceID(deviceID);
+  CopyUTF16toUTF8(deviceID, narrowDeviceID);
+  GetAdapterVendorID(vendorID);
+  CopyUTF16toUTF8(vendorID, narrowVendorID);
+  GetAdapterDriverVersion(driverVersion);
+  CopyUTF16toUTF8(driverVersion, narrowDriverVersion);
+
+  CrashReporter::AnnotateCrashReport(CrashReporter::Annotation::AdapterVendorID,
+                                     narrowVendorID);
+  CrashReporter::AnnotateCrashReport(CrashReporter::Annotation::AdapterDeviceID,
+                                     narrowDeviceID);
+  CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::AdapterDriverVersion, narrowDriverVersion);
+}
+
+// We don't support checking driver versions on Mac.
+#define IMPLEMENT_MAC_DRIVER_BLOCKLIST(os, device, features, blockOn, ruleId)  \
+  APPEND_TO_DRIVER_BLOCKLIST(os, device, features, blockOn,                    \
+                             DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0), ruleId, \
+                             "")
+
+const nsTArray<GfxDriverInfo>& GfxInfo::GetGfxDriverInfo() {
+  if (!sDriverInfo->Length()) {
+    IMPLEMENT_MAC_DRIVER_BLOCKLIST(
+        OperatingSystem::OSX, DeviceFamily::RadeonX1000,
+        nsIGfxInfo::FEATURE_OPENGL_LAYERS, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        "FEATURE_FAILURE_MAC_RADEONX1000_NO_TEXTURE2D");
+    IMPLEMENT_MAC_DRIVER_BLOCKLIST(
+        OperatingSystem::OSX, DeviceFamily::Geforce7300GT,
+        nsIGfxInfo::FEATURE_WEBGL_OPENGL, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        "FEATURE_FAILURE_MAC_7300_NO_WEBGL");
+    IMPLEMENT_MAC_DRIVER_BLOCKLIST(
+        OperatingSystem::OSX, DeviceFamily::IntelHDGraphicsToIvyBridge,
+        nsIGfxInfo::FEATURE_GL_SWIZZLE, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        "FEATURE_FAILURE_MAC_INTELHD4000_NO_SWIZZLE");
+    // We block texture swizzling everwhere on mac because it's broken in some
+    // configurations and we want to support GPU switching.
+    IMPLEMENT_MAC_DRIVER_BLOCKLIST(
+        OperatingSystem::OSX, DeviceFamily::All, nsIGfxInfo::FEATURE_GL_SWIZZLE,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        "FEATURE_FAILURE_MAC_GPU_SWITCHING_NO_SWIZZLE");
+
+    // Older generation Intel devices do not perform well with WebRender.
+    IMPLEMENT_MAC_DRIVER_BLOCKLIST(
+        OperatingSystem::OSX, DeviceFamily::IntelWebRenderBlocked,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        "FEATURE_FAILURE_INTEL_GEN5_OR_OLDER");
+
+    // Intel HD3000 disabled due to bug 1661505
+    IMPLEMENT_MAC_DRIVER_BLOCKLIST(
+        OperatingSystem::OSX, DeviceFamily::IntelSandyBridge,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        "FEATURE_FAILURE_INTEL_MAC_HD3000_NO_WEBRENDER");
+
+    // wgpu doesn't safely support OOB behavior on Metal yet.
+    IMPLEMENT_MAC_DRIVER_BLOCKLIST(
+        OperatingSystem::OSX, DeviceFamily::All, nsIGfxInfo::FEATURE_WEBGPU,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        "FEATURE_FAILURE_MAC_WGPU_NO_METAL_BOUNDS_CHECKS");
+  }
+  return *sDriverInfo;
+}
+
+OperatingSystem GfxInfo::GetOperatingSystem() {
+  return OSXVersionToOperatingSystem(mOSXVersion);
+}
+
+nsresult GfxInfo::GetFeatureStatusImpl(
+    int32_t aFeature, int32_t* aStatus, nsAString& aSuggestedDriverVersion,
+    const nsTArray<GfxDriverInfo>& aDriverInfo, nsACString& aFailureId,
+    OperatingSystem* aOS /* = nullptr */) {
+  NS_ENSURE_ARG_POINTER(aStatus);
+  aSuggestedDriverVersion.SetIsVoid(true);
+  *aStatus = nsIGfxInfo::FEATURE_STATUS_UNKNOWN;
+  OperatingSystem os = OSXVersionToOperatingSystem(mOSXVersion);
+  if (aOS) *aOS = os;
+
+  if (sShutdownOccurred) {
+    return NS_OK;
+  }
+
+  // Don't evaluate special cases when we're evaluating the downloaded
+  // blocklist.
+  if (!aDriverInfo.Length()) {
+    if (aFeature == nsIGfxInfo::FEATURE_CANVAS2D_ACCELERATION) {
+      // See bug 1249659
+      switch (os) {
+        case OperatingSystem::OSX10_5:
+        case OperatingSystem::OSX10_6:
+        case OperatingSystem::OSX10_7:
+          *aStatus = nsIGfxInfo::FEATURE_BLOCKED_OS_VERSION;
+          aFailureId = "FEATURE_FAILURE_CANVAS_OSX_VERSION";
+          break;
+        default:
+          *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+          break;
+      }
+      return NS_OK;
+    } else if (aFeature == nsIGfxInfo::FEATURE_WEBRENDER &&
+               nsCocoaFeatures::ProcessIsRosettaTranslated()) {
+      *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+      aFailureId = "FEATURE_UNQUALIFIED_WEBRENDER_MAC_ROSETTA";
+      return NS_OK;
+    }
+  }
+
+  return GfxInfoBase::GetFeatureStatusImpl(
+      aFeature, aStatus, aSuggestedDriverVersion, aDriverInfo, aFailureId, &os);
+}
+
+#ifdef DEBUG
+
+// Implement nsIGfxInfoDebug
+
+/* void spoofVendorID (in DOMString aVendorID); */
+NS_IMETHODIMP GfxInfo::SpoofVendorID(const nsAString& aVendorID) {
+  mAdapterVendorID[0] = aVendorID;
+  return NS_OK;
+}
+
+/* void spoofDeviceID (in unsigned long aDeviceID); */
+NS_IMETHODIMP GfxInfo::SpoofDeviceID(const nsAString& aDeviceID) {
+  mAdapterDeviceID[0] = aDeviceID;
+  return NS_OK;
+}
+
+/* void spoofDriverVersion (in DOMString aDriverVersion); */
+NS_IMETHODIMP GfxInfo::SpoofDriverVersion(const nsAString& aDriverVersion) {
+  mDriverVersion[0] = aDriverVersion;
+  return NS_OK;
+}
+
+/* void spoofOSVersion (in unsigned long aVersion); */
+NS_IMETHODIMP GfxInfo::SpoofOSVersion(uint32_t aVersion) {
+  mOSXVersion = aVersion;
+  return NS_OK;
+}
+
+#endif
diff --git a/widget/cocoa/MOZIconHelper.h b/widget/cocoa/MOZIconHelper.h
new file mode 100644
index 0000000000..4b66f13c05
--- /dev/null
+++ b/widget/cocoa/MOZIconHelper.h
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZIconHelper_h
+#define MOZIconHelper_h
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsRect.h"
+
+class imgIContainer;
+class nsPresContext;
+
+namespace mozilla {
+class ComputedStyle;
+}
+
+@interface MOZIconHelper : NSObject
+
+// Returns an autoreleased empty NSImage.
++ (NSImage*)placeholderIconWithSize:(NSSize)aSize;
+
+// Returns an autoreleased NSImage.
++ (NSImage*)iconImageFromImageContainer:(imgIContainer*)aImage
+                               withSize:(NSSize)aSize
+                            presContext:(const nsPresContext*)aPresContext
+                          computedStyle:
+                              (const mozilla::ComputedStyle*)aComputedStyle
+                            scaleFactor:(CGFloat)aScaleFactor;
+
+@end
+
+#endif  // MOZIconHelper_h
diff --git a/widget/cocoa/MOZIconHelper.mm b/widget/cocoa/MOZIconHelper.mm
new file mode 100644
index 0000000000..e15407b797
--- /dev/null
+++ b/widget/cocoa/MOZIconHelper.mm
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Creates icons for display in native menu items on macOS.
+ */
+
+#include "MOZIconHelper.h"
+
+#include "imgIContainer.h"
+#include "nsCocoaUtils.h"
+
+@implementation MOZIconHelper
+
+// Returns an autoreleased empty NSImage.
++ (NSImage*)placeholderIconWithSize:(NSSize)aSize {
+  return [[[NSImage alloc] initWithSize:aSize] autorelease];
+}
+
+// Returns an autoreleased NSImage.
++ (NSImage*)iconImageFromImageContainer:(imgIContainer*)aImage
+                               withSize:(NSSize)aSize
+                            presContext:(const nsPresContext*)aPresContext
+                          computedStyle:
+                              (const mozilla::ComputedStyle*)aComputedStyle
+                            scaleFactor:(CGFloat)aScaleFactor {
+  bool isEntirelyBlack = false;
+  NSImage* retainedImage = nil;
+  nsresult rv;
+  if (aScaleFactor != 0.0f) {
+    rv = nsCocoaUtils::CreateNSImageFromImageContainer(
+        aImage, imgIContainer::FRAME_CURRENT, aPresContext, aComputedStyle,
+        &retainedImage, aScaleFactor, &isEntirelyBlack);
+  } else {
+    rv = nsCocoaUtils::CreateDualRepresentationNSImageFromImageContainer(
+        aImage, imgIContainer::FRAME_CURRENT, aPresContext, aComputedStyle,
+        &retainedImage, &isEntirelyBlack);
+  }
+
+  NSImage* image = [retainedImage autorelease];
+
+  if (NS_FAILED(rv) || !image) {
+    return nil;
+  }
+
+  int32_t origWidth = 0, origHeight = 0;
+  aImage->GetWidth(&origWidth);
+  aImage->GetHeight(&origHeight);
+
+  // If all the color channels in the image are black, treat the image as a
+  // template. This will cause macOS to use the image's alpha channel as a mask
+  // and it will fill it with a color that looks good in the context that it's
+  // used in. For example, for regular menu items, the image will be black, but
+  // when the menu item is hovered (and its background is blue), it will be
+  // filled with white.
+  [image setTemplate:isEntirelyBlack];
+
+  [image setSize:aSize];
+
+  return image;
+}
+
+@end
diff --git a/widget/cocoa/MOZMenuOpeningCoordinator.h b/widget/cocoa/MOZMenuOpeningCoordinator.h
new file mode 100644
index 0000000000..eed6ed58fa
--- /dev/null
+++ b/widget/cocoa/MOZMenuOpeningCoordinator.h
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZMenuOpeningCoordinator_h
+#define MOZMenuOpeningCoordinator_h
+
+#import <Cocoa/Cocoa.h>
+
+#include "mozilla/RefPtr.h"
+
+namespace mozilla {
+class Runnable;
+}
+
+/*
+ * MOZMenuOpeningCoordinator is a workaround for the fact that opening an NSMenu
+ * creates a nested event loop. This event loop is only exited after the menu is
+ * closed. The caller of NativeMenuMac::ShowAsContextMenu does not expect
+ * ShowAsContextMenu to create a nested event loop, so we need to make sure to
+ * open the NSMenu asynchronously.
+ */
+
+@interface MOZMenuOpeningCoordinator : NSObject
+
++ (instancetype)sharedInstance;
+
+// Queue aMenu for opening.
+// The menu will open from a new event loop tick so that its nested event loop
+// does not block the caller. If another menu's nested event loop is currently
+// on the stack, we wait for that nested event loop to unwind before opening
+// aMenu. Returns a handle that can be passed to cancelAsynchronousOpening:. Can
+// only be called on the main thread.
+- (NSInteger)asynchronouslyOpenMenu:(NSMenu*)aMenu
+                   atScreenPosition:(NSPoint)aPosition
+                            forView:(NSView*)aView
+                     withAppearance:(NSAppearance*)aAppearance
+                      asContextMenu:(BOOL)aIsContextMenu;
+
+// If the menu opening request for aHandle hasn't been processed yet, cancel it.
+// Can only be called on the main thread.
+- (void)cancelAsynchronousOpening:(NSInteger)aHandle;
+
+// This field is a terrible workaround for a gnarly problem.
+// It should be set to YES by the caller of -[NSMenu
+// cancelTracking(WithoutAnimation)]. This field gets checked by the native
+// event loop code in nsAppShell.mm to avoid calling
+// -[NSApplication nextEventMatchingMask:...] between the call to cancelTracking
+// and the point at which the menu has finished closing and unwound from its
+// tracking event loop, because such calls can interfere with menu closing and
+// get us stuck in the menu event loop forever.
+@property(class) BOOL needToUnwindForMenuClosing;
+
+@end
+
+#endif  // MOZMenuOpeningCoordinator_h
diff --git a/widget/cocoa/MOZMenuOpeningCoordinator.mm b/widget/cocoa/MOZMenuOpeningCoordinator.mm
new file mode 100644
index 0000000000..800859a92a
--- /dev/null
+++ b/widget/cocoa/MOZMenuOpeningCoordinator.mm
@@ -0,0 +1,224 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Makes sure that the nested event loop for NSMenu tracking is situated as low
+ * on the stack as possible, and that two NSMenu event loops are never nested.
+ */
+
+#include "MOZMenuOpeningCoordinator.h"
+
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/StaticPrefs_widget.h"
+
+#include "nsCocoaFeatures.h"
+#include "nsCocoaUtils.h"
+#include "nsMenuX.h"
+#include "nsObjCExceptions.h"
+
+static BOOL sNeedToUnwindForMenuClosing = NO;
+
+@interface MOZMenuOpeningInfo : NSObject
+@property NSInteger handle;
+@property(retain) NSMenu* menu;
+@property NSPoint position;
+@property(retain) NSView* view;
+@property(retain) NSAppearance* appearance;
+@property BOOL isContextMenu;
+@end
+
+@implementation MOZMenuOpeningInfo
+@end
+
+@implementation MOZMenuOpeningCoordinator {
+  // non-nil between asynchronouslyOpenMenu:atScreenPosition:forView: and the
+  // time at at which it is unqueued in _runMenu.
+  MOZMenuOpeningInfo* mPendingOpening;  // strong
+
+  // An incrementing counter
+  NSInteger mLastHandle;
+
+  // YES while _runMenu is on the stack
+  BOOL mRunMenuIsOnTheStack;
+}
+
++ (instancetype)sharedInstance {
+  static MOZMenuOpeningCoordinator* sInstance = nil;
+  if (!sInstance) {
+    sInstance = [[MOZMenuOpeningCoordinator alloc] init];
+    mozilla::RunOnShutdown([&]() {
+      [sInstance release];
+      sInstance = nil;
+    });
+  }
+  return sInstance;
+}
+
+- (void)dealloc {
+  MOZ_RELEASE_ASSERT(!mPendingOpening, "should be empty at shutdown");
+  [super dealloc];
+}
+
+- (NSInteger)asynchronouslyOpenMenu:(NSMenu*)aMenu
+                   atScreenPosition:(NSPoint)aPosition
+                            forView:(NSView*)aView
+                     withAppearance:(NSAppearance*)aAppearance
+                      asContextMenu:(BOOL)aIsContextMenu {
+  MOZ_RELEASE_ASSERT(!mPendingOpening,
+                     "A menu is already waiting to open. Before opening the "
+                     "next one, either wait "
+                     "for this one to open or cancel the request.");
+
+  NSInteger handle = ++mLastHandle;
+
+  MOZMenuOpeningInfo* info = [[MOZMenuOpeningInfo alloc] init];
+  info.handle = handle;
+  info.menu = aMenu;
+  info.position = aPosition;
+  info.view = aView;
+  info.appearance = aAppearance;
+  info.isContextMenu = aIsContextMenu;
+  mPendingOpening = [info retain];
+  [info release];
+
+  if (!mRunMenuIsOnTheStack) {
+    // Call _runMenu from the event loop, so that it doesn't block this call.
+    [self performSelector:@selector(_runMenu) withObject:nil afterDelay:0.0];
+  }
+
+  return handle;
+}
+
+- (void)_runMenu {
+  MOZ_RELEASE_ASSERT(!mRunMenuIsOnTheStack);
+
+  mRunMenuIsOnTheStack = YES;
+
+  while (mPendingOpening) {
+    MOZMenuOpeningInfo* info = [mPendingOpening retain];
+    [mPendingOpening release];
+    mPendingOpening = nil;
+
+    @try {
+      [self _openMenu:info.menu
+          atScreenPosition:info.position
+                   forView:info.view
+            withAppearance:info.appearance
+             asContextMenu:info.isContextMenu];
+    } @catch (NSException* exception) {
+      nsObjCExceptionLog(exception);
+    }
+
+    [info release];
+
+    // We have exited _openMenu's nested event loop.
+    MOZMenuOpeningCoordinator.needToUnwindForMenuClosing = NO;
+  }
+
+  mRunMenuIsOnTheStack = NO;
+}
+
+- (void)cancelAsynchronousOpening:(NSInteger)aHandle {
+  if (mPendingOpening && mPendingOpening.handle == aHandle) {
+    [NSObject cancelPreviousPerformRequestsWithTarget:self
+                                             selector:@selector(_runMenu)
+                                               object:nil];
+    [mPendingOpening release];
+    mPendingOpening = nil;
+  }
+}
+
+- (void)_openMenu:(NSMenu*)aMenu
+    atScreenPosition:(NSPoint)aPosition
+             forView:(NSView*)aView
+      withAppearance:(NSAppearance*)aAppearance
+       asContextMenu:(BOOL)aIsContextMenu {
+  // There are multiple ways to display an NSMenu as a context menu.
+  //
+  //  1. We can return the NSMenu from -[ChildView menuForEvent:] and the NSView
+  //     will open it for us.
+  //  2. We can call +[NSMenu popUpContextMenu:withEvent:forView:] inside a
+  //     mouseDown handler with a real mouse down event.
+  //  3. We can call +[NSMenu popUpContextMenu:withEvent:forView:] at a later
+  //     time, with a real mouse event that we stored earlier.
+  //  4. We can call +[NSMenu popUpContextMenu:withEvent:forView:] at any time,
+  //     with a synthetic mouse event that we create just for that purpose.
+  //  5. We can call -[NSMenu popUpMenuPositioningItem:atLocation:inView:] and
+  //     it just takes a position, not an event.
+  //
+  // 1-4 look the same, 5 looks different: 5 is made for use with NSPopUpButton,
+  // where the selected item needs to be shown at a specific position. If a tall
+  // menu is opened with a position close to the bottom edge of the screen, 5
+  // results in a cropped menu with scroll arrows, even if the entire menu would
+  // fit on the screen, due to the positioning constraint. 1-2 only work if the
+  // menu contents are known synchronously during the call to menuForEvent or
+  // during the mouseDown event handler.
+  // NativeMenuMac::ShowAsContextMenu can be called at any time. It could be
+  // called during a menuForEvent call (during a "contextmenu" event handler),
+  // or during a mouseDown handler, or at a later time. The code below uses
+  // option 4 as the preferred option for context menus because it's the
+  // simplest: It works in all scenarios and it doesn't have the drawbacks of
+  // option 5. For popups that aren't context menus and that should be
+  // positioned as close as possible to the given screen position, we use
+  // option 5.
+
+  if (aAppearance) {
+    if (@available(macOS 11.0, *)) {
+      // By default, NSMenu inherits its appearance from the opening NSEvent's
+      // window. If CSS has overridden it, on Big Sur + we can respect it with
+      // -[NSMenu setAppearance].
+      aMenu.appearance = aAppearance;
+    }
+  }
+
+  if (aView) {
+    NSWindow* window = aView.window;
+    NSPoint locationInWindow =
+        nsCocoaUtils::ConvertPointFromScreen(window, aPosition);
+    if (aIsContextMenu) {
+      // Create a synthetic event at the right location and open the menu
+      // [option 4].
+      NSEvent* event =
+          [NSEvent mouseEventWithType:NSEventTypeRightMouseDown
+                             location:locationInWindow
+                        modifierFlags:0
+                            timestamp:NSProcessInfo.processInfo.systemUptime
+                         windowNumber:window.windowNumber
+                              context:nil
+                          eventNumber:0
+                           clickCount:1
+                             pressure:0.0f];
+      [NSMenu popUpContextMenu:aMenu withEvent:event forView:aView];
+    } else {
+      // For popups which are not context menus, we open the menu using [option
+      // 5]. We pass `nil` to indicate that we're positioning the top left
+      // corner of the menu. This path is used for anchored menupopups, so we
+      // prefer option 5 over option 4 so that the menu doesn't get flipped if
+      // space is tight.
+      NSPoint locationInView = [aView convertPoint:locationInWindow
+                                          fromView:nil];
+      [aMenu popUpMenuPositioningItem:nil
+                           atLocation:locationInView
+                               inView:aView];
+    }
+  } else {
+    // Open the menu using popUpMenuPositioningItem:atLocation:inView: [option
+    // 5]. This is not preferred, because it positions the menu differently from
+    // how a native context menu would be positioned; it enforces aPosition for
+    // the top left corner even if this means that the menu will be displayed in
+    // a clipped fashion with scroll arrows.
+    [aMenu popUpMenuPositioningItem:nil atLocation:aPosition inView:nil];
+  }
+}
+
++ (void)setNeedToUnwindForMenuClosing:(BOOL)aValue {
+  sNeedToUnwindForMenuClosing = aValue;
+}
+
++ (BOOL)needToUnwindForMenuClosing {
+  return sNeedToUnwindForMenuClosing;
+}
+
+@end
diff --git a/widget/cocoa/MacThemeGeometryType.h b/widget/cocoa/MacThemeGeometryType.h
new file mode 100644
index 0000000000..4691dbdec2
--- /dev/null
+++ b/widget/cocoa/MacThemeGeometryType.h
@@ -0,0 +1,17 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef mozilla_widget_ThemeGeometryType
+#define mozilla_widget_ThemeGeometryType
+
+enum MacThemeGeometryType {
+  eThemeGeometryTypeTitlebar = 1,
+  eThemeGeometryTypeToolbar,
+  eThemeGeometryTypeToolbox,
+  eThemeGeometryTypeWindowButtons,
+  eThemeGeometryTypeMenu,
+  eThemeGeometryTypeTooltip,
+};
+
+#endif
diff --git a/widget/cocoa/MediaHardwareKeysEventSourceMac.h b/widget/cocoa/MediaHardwareKeysEventSourceMac.h
new file mode 100644
index 0000000000..da08b8108d
--- /dev/null
+++ b/widget/cocoa/MediaHardwareKeysEventSourceMac.h
@@ -0,0 +1,47 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_COCOA_MEDIAHARDWAREKEYSEVENTSOURCEMAC_H_
+#define WIDGET_COCOA_MEDIAHARDWAREKEYSEVENTSOURCEMAC_H_
+
+#import <ApplicationServices/ApplicationServices.h>
+#import <CoreFoundation/CoreFoundation.h>
+
+#include "mozilla/dom/MediaControlKeySource.h"
+#include "nsISupportsImpl.h"
+
+namespace mozilla {
+namespace widget {
+
+class MediaHardwareKeysEventSourceMac final
+    : public mozilla::dom::MediaControlKeySource {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(MediaHardwareKeysEventSourceMac, override)
+  MediaHardwareKeysEventSourceMac() = default;
+
+  static CGEventRef EventTapCallback(CGEventTapProxy proxy, CGEventType type,
+                                     CGEventRef event, void* refcon);
+
+  bool Open() override;
+  void Close() override;
+  bool IsOpened() const override;
+
+  // Currently we don't support showing supported keys on the touch bar.
+  void SetSupportedMediaKeys(const MediaKeysArray& aSupportedKeys) override {}
+
+ private:
+  ~MediaHardwareKeysEventSourceMac() = default;
+
+  bool StartEventTap();
+  void StopEventTap();
+
+  // They are used to intercept mac hardware media keys.
+  CFMachPortRef mEventTap = nullptr;
+  CFRunLoopSourceRef mEventTapSource = nullptr;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/cocoa/MediaHardwareKeysEventSourceMac.mm b/widget/cocoa/MediaHardwareKeysEventSourceMac.mm
new file mode 100644
index 0000000000..9a6991a181
--- /dev/null
+++ b/widget/cocoa/MediaHardwareKeysEventSourceMac.mm
@@ -0,0 +1,191 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaHardwareKeysEventSourceMac.h"
+
+#import <AppKit/AppKit.h>
+#import <AppKit/NSEvent.h>
+#import <IOKit/hidsystem/ev_keymap.h>
+
+#include "mozilla/dom/MediaControlUtils.h"
+
+using namespace mozilla::dom;
+
+// avoid redefined macro in unified build
+#undef LOG
+#define LOG(msg, ...)                        \
+  MOZ_LOG(gMediaControlLog, LogLevel::Debug, \
+          ("MediaHardwareKeysEventSourceMac=%p, " msg, this, ##__VA_ARGS__))
+
+// This macro is used in static callback function, where we have to send `this`
+// explicitly.
+#define LOG2(msg, this, ...)                 \
+  MOZ_LOG(gMediaControlLog, LogLevel::Debug, \
+          ("MediaHardwareKeysEventSourceMac=%p, " msg, this, ##__VA_ARGS__))
+
+static const char* ToMediaControlKeyStr(int aKeyCode) {
+  switch (aKeyCode) {
+    case NX_KEYTYPE_PLAY:
+      return "Play";
+    case NX_KEYTYPE_NEXT:
+      return "Next";
+    case NX_KEYTYPE_PREVIOUS:
+      return "Previous";
+    case NX_KEYTYPE_FAST:
+      return "Fast";
+    case NX_KEYTYPE_REWIND:
+      return "Rewind";
+    default:
+      MOZ_ASSERT_UNREACHABLE("Invalid key code.");
+      return "UNKNOWN";
+  }
+}
+
+// The media keys subtype. No official docs found, but widely known.
+// http://lists.apple.com/archives/cocoa-dev/2007/Aug/msg00499.html
+const int kSystemDefinedEventMediaKeysSubtype = 8;
+
+static bool IsSupportedKeyCode(int aKeyCode) {
+  return aKeyCode == NX_KEYTYPE_PLAY || aKeyCode == NX_KEYTYPE_NEXT ||
+         aKeyCode == NX_KEYTYPE_FAST || aKeyCode == NX_KEYTYPE_PREVIOUS ||
+         aKeyCode == NX_KEYTYPE_REWIND;
+}
+
+static MediaControlKey ToMediaControlKey(int aKeyCode) {
+  MOZ_ASSERT(IsSupportedKeyCode(aKeyCode));
+  switch (aKeyCode) {
+    case NX_KEYTYPE_NEXT:
+    case NX_KEYTYPE_FAST:
+      return MediaControlKey::Nexttrack;
+    case NX_KEYTYPE_PREVIOUS:
+    case NX_KEYTYPE_REWIND:
+      return MediaControlKey::Previoustrack;
+    default:
+      MOZ_ASSERT(aKeyCode == NX_KEYTYPE_PLAY);
+      return MediaControlKey::Playpause;
+  }
+}
+
+namespace mozilla {
+namespace widget {
+
+bool MediaHardwareKeysEventSourceMac::IsOpened() const {
+  return mEventTap && mEventTapSource;
+}
+
+bool MediaHardwareKeysEventSourceMac::Open() {
+  LOG("Open MediaHardwareKeysEventSourceMac");
+  return StartEventTap();
+}
+
+void MediaHardwareKeysEventSourceMac::Close() {
+  LOG("Close MediaHardwareKeysEventSourceMac");
+  StopEventTap();
+  MediaControlKeySource::Close();
+}
+
+bool MediaHardwareKeysEventSourceMac::StartEventTap() {
+  LOG("StartEventTap");
+  MOZ_ASSERT(!mEventTap);
+  MOZ_ASSERT(!mEventTapSource);
+
+  // Add an event tap to intercept the system defined media key events.
+  mEventTap = CGEventTapCreate(
+      kCGSessionEventTap, kCGHeadInsertEventTap, kCGEventTapOptionListenOnly,
+      CGEventMaskBit(NX_SYSDEFINED), EventTapCallback, this);
+  if (!mEventTap) {
+    LOG("Fail to create event tap");
+    return false;
+  }
+
+  mEventTapSource =
+      CFMachPortCreateRunLoopSource(kCFAllocatorDefault, mEventTap, 0);
+  if (!mEventTapSource) {
+    LOG("Fail to create an event tap source.");
+    return false;
+  }
+
+  LOG("Add an event tap source to current loop");
+  CFRunLoopAddSource(CFRunLoopGetCurrent(), mEventTapSource,
+                     kCFRunLoopCommonModes);
+  return true;
+}
+
+void MediaHardwareKeysEventSourceMac::StopEventTap() {
+  LOG("StopEventTapIfNecessary");
+  if (mEventTap) {
+    CFMachPortInvalidate(mEventTap);
+    mEventTap = nullptr;
+  }
+  if (mEventTapSource) {
+    CFRunLoopRemoveSource(CFRunLoopGetCurrent(), mEventTapSource,
+                          kCFRunLoopCommonModes);
+    CFRelease(mEventTapSource);
+    mEventTapSource = nullptr;
+  }
+}
+
+CGEventRef MediaHardwareKeysEventSourceMac::EventTapCallback(
+    CGEventTapProxy proxy, CGEventType type, CGEventRef event, void* refcon) {
+  // Re-enable event tap when receiving disabled events.
+  MediaHardwareKeysEventSourceMac* source =
+      static_cast<MediaHardwareKeysEventSourceMac*>(refcon);
+  if (type == kCGEventTapDisabledByUserInput ||
+      type == kCGEventTapDisabledByTimeout) {
+    MOZ_ASSERT(source->mEventTap);
+    CGEventTapEnable(source->mEventTap, true);
+    return event;
+  }
+
+  NSEvent* nsEvent = [NSEvent eventWithCGEvent:event];
+  if (nsEvent == nil) {
+    return event;
+  }
+
+  // Ignore not system defined media keys event.
+  if ([nsEvent type] != NSEventTypeSystemDefined ||
+      [nsEvent subtype] != kSystemDefinedEventMediaKeysSubtype) {
+    return event;
+  }
+
+  // Ignore media keys that aren't previous, next and play/pause.
+  // Magical constants are from http://weblog.rogueamoeba.com/2007/09/29/
+  // - keyCode = (([event data1] & 0xFFFF0000) >> 16)
+  // - keyFlags = ([event data1] & 0x0000FFFF)
+  // - keyState = (((keyFlags & 0xFF00) >> 8)) == 0xA
+  // - keyRepeat = (keyFlags & 0x1);
+  const NSInteger data1 = [nsEvent data1];
+  int keyCode = (data1 & 0xFFFF0000) >> 16;
+  if (keyCode != NX_KEYTYPE_PLAY && keyCode != NX_KEYTYPE_NEXT &&
+      keyCode != NX_KEYTYPE_PREVIOUS && keyCode != NX_KEYTYPE_FAST &&
+      keyCode != NX_KEYTYPE_REWIND) {
+    return event;
+  }
+
+  // Ignore non-key pressed event (eg. key released).
+  int keyFlags = data1 & 0x0000FFFF;
+  bool isKeyPressed = ((keyFlags & 0xFF00) >> 8) == 0xA;
+  if (!isKeyPressed) {
+    return event;
+  }
+
+  // There is no listener waiting to process event.
+  if (source->mListeners.IsEmpty()) {
+    return event;
+  }
+
+  if (!IsSupportedKeyCode(keyCode)) {
+    return event;
+  }
+
+  LOG2("Get media key %s", source, ToMediaControlKeyStr(keyCode));
+  for (auto iter = source->mListeners.begin(); iter != source->mListeners.end();
+       ++iter) {
+    (*iter)->OnActionPerformed(MediaControlAction(ToMediaControlKey(keyCode)));
+  }
+  return event;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/cocoa/MediaHardwareKeysEventSourceMacMediaCenter.h b/widget/cocoa/MediaHardwareKeysEventSourceMacMediaCenter.h
new file mode 100644
index 0000000000..c2b9d93000
--- /dev/null
+++ b/widget/cocoa/MediaHardwareKeysEventSourceMacMediaCenter.h
@@ -0,0 +1,62 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_COCOA_MEDIAHARDWAREKEYSEVENTSOURCEMACMEDIACENTER_H_
+#define WIDGET_COCOA_MEDIAHARDWAREKEYSEVENTSOURCEMACMEDIACENTER_H_
+
+#include "mozilla/dom/MediaControlKeySource.h"
+
+#ifdef __OBJC__
+@class MPRemoteCommandEvent;
+#else
+typedef struct objc_object MPRemoteCommandEvent;
+#endif
+enum MPRemoteCommandHandlerStatus : long;
+
+namespace mozilla {
+namespace widget {
+
+typedef MPRemoteCommandHandlerStatus (^MediaCenterEventHandler)(
+    MPRemoteCommandEvent* event);
+
+class MediaHardwareKeysEventSourceMacMediaCenter final
+    : public mozilla::dom::MediaControlKeySource {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(MediaHardwareKeysEventSourceMacMediaCenter,
+                             override)
+  MediaHardwareKeysEventSourceMacMediaCenter();
+
+  MediaCenterEventHandler CreatePlayPauseHandler();
+  MediaCenterEventHandler CreateNextTrackHandler();
+  MediaCenterEventHandler CreatePreviousTrackHandler();
+  MediaCenterEventHandler CreatePlayHandler();
+  MediaCenterEventHandler CreatePauseHandler();
+
+  bool Open() override;
+  void Close() override;
+  bool IsOpened() const override;
+  void SetPlaybackState(dom::MediaSessionPlaybackState aState) override;
+  void SetMediaMetadata(const dom::MediaMetadataBase& aMetadata) override;
+  // Currently we don't support showing supported keys on the touch bar.
+  void SetSupportedMediaKeys(const MediaKeysArray& aSupportedKeys) override {}
+
+ private:
+  ~MediaHardwareKeysEventSourceMacMediaCenter();
+  void BeginListeningForEvents();
+  void EndListeningForEvents();
+  void HandleEvent(dom::MediaControlKey aKey);
+
+  bool mOpened = false;
+
+  MediaCenterEventHandler mPlayPauseHandler;
+  MediaCenterEventHandler mNextTrackHandler;
+  MediaCenterEventHandler mPreviousTrackHandler;
+  MediaCenterEventHandler mPauseHandler;
+  MediaCenterEventHandler mPlayHandler;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // WIDGET_COCOA_MEDIAHARDWAREKEYSEVENTSOURCEMACMEDIACENTER_H_
diff --git a/widget/cocoa/MediaHardwareKeysEventSourceMacMediaCenter.mm b/widget/cocoa/MediaHardwareKeysEventSourceMacMediaCenter.mm
new file mode 100644
index 0000000000..c7a85326fb
--- /dev/null
+++ b/widget/cocoa/MediaHardwareKeysEventSourceMacMediaCenter.mm
@@ -0,0 +1,187 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <MediaPlayer/MediaPlayer.h>
+
+#include "MediaHardwareKeysEventSourceMacMediaCenter.h"
+
+#include "mozilla/dom/MediaControlUtils.h"
+#include "nsCocoaUtils.h"
+
+using namespace mozilla::dom;
+
+// avoid redefined macro in unified build
+#undef LOG
+#define LOG(msg, ...)                                                   \
+  MOZ_LOG(gMediaControlLog, LogLevel::Debug,                            \
+          ("MediaHardwareKeysEventSourceMacMediaCenter=%p, " msg, this, \
+           ##__VA_ARGS__))
+
+namespace mozilla {
+namespace widget {
+
+MediaCenterEventHandler
+MediaHardwareKeysEventSourceMacMediaCenter::CreatePlayPauseHandler() {
+  return Block_copy(^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent* event) {
+    MPNowPlayingInfoCenter* center = [MPNowPlayingInfoCenter defaultCenter];
+    center.playbackState =
+        center.playbackState == MPNowPlayingPlaybackStatePlaying
+            ? MPNowPlayingPlaybackStatePaused
+            : MPNowPlayingPlaybackStatePlaying;
+    HandleEvent(MediaControlKey::Playpause);
+    return MPRemoteCommandHandlerStatusSuccess;
+  });
+}
+
+MediaCenterEventHandler
+MediaHardwareKeysEventSourceMacMediaCenter::CreateNextTrackHandler() {
+  return Block_copy(^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent* event) {
+    HandleEvent(MediaControlKey::Nexttrack);
+    return MPRemoteCommandHandlerStatusSuccess;
+  });
+}
+
+MediaCenterEventHandler
+MediaHardwareKeysEventSourceMacMediaCenter::CreatePreviousTrackHandler() {
+  return Block_copy(^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent* event) {
+    HandleEvent(MediaControlKey::Previoustrack);
+    return MPRemoteCommandHandlerStatusSuccess;
+  });
+}
+
+MediaCenterEventHandler
+MediaHardwareKeysEventSourceMacMediaCenter::CreatePlayHandler() {
+  return Block_copy(^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent* event) {
+    MPNowPlayingInfoCenter* center = [MPNowPlayingInfoCenter defaultCenter];
+    if (center.playbackState != MPNowPlayingPlaybackStatePlaying) {
+      center.playbackState = MPNowPlayingPlaybackStatePlaying;
+    }
+    HandleEvent(MediaControlKey::Play);
+    return MPRemoteCommandHandlerStatusSuccess;
+  });
+}
+
+MediaCenterEventHandler
+MediaHardwareKeysEventSourceMacMediaCenter::CreatePauseHandler() {
+  return Block_copy(^MPRemoteCommandHandlerStatus(MPRemoteCommandEvent* event) {
+    MPNowPlayingInfoCenter* center = [MPNowPlayingInfoCenter defaultCenter];
+    if (center.playbackState != MPNowPlayingPlaybackStatePaused) {
+      center.playbackState = MPNowPlayingPlaybackStatePaused;
+    }
+    HandleEvent(MediaControlKey::Pause);
+    return MPRemoteCommandHandlerStatusSuccess;
+  });
+}
+
+MediaHardwareKeysEventSourceMacMediaCenter::
+    MediaHardwareKeysEventSourceMacMediaCenter() {
+  mPlayPauseHandler = CreatePlayPauseHandler();
+  mNextTrackHandler = CreateNextTrackHandler();
+  mPreviousTrackHandler = CreatePreviousTrackHandler();
+  mPlayHandler = CreatePlayHandler();
+  mPauseHandler = CreatePauseHandler();
+  LOG("Create MediaHardwareKeysEventSourceMacMediaCenter");
+}
+
+MediaHardwareKeysEventSourceMacMediaCenter::
+    ~MediaHardwareKeysEventSourceMacMediaCenter() {
+  LOG("Destroy MediaHardwareKeysEventSourceMacMediaCenter");
+  EndListeningForEvents();
+  MPNowPlayingInfoCenter* center = [MPNowPlayingInfoCenter defaultCenter];
+  center.playbackState = MPNowPlayingPlaybackStateStopped;
+}
+
+void MediaHardwareKeysEventSourceMacMediaCenter::BeginListeningForEvents() {
+  MPNowPlayingInfoCenter* center = [MPNowPlayingInfoCenter defaultCenter];
+  center.playbackState = MPNowPlayingPlaybackStatePlaying;
+  MPRemoteCommandCenter* commandCenter =
+      [MPRemoteCommandCenter sharedCommandCenter];
+  commandCenter.togglePlayPauseCommand.enabled = true;
+  [commandCenter.togglePlayPauseCommand addTargetWithHandler:mPlayPauseHandler];
+  commandCenter.nextTrackCommand.enabled = true;
+  [commandCenter.nextTrackCommand addTargetWithHandler:mNextTrackHandler];
+  commandCenter.previousTrackCommand.enabled = true;
+  [commandCenter.previousTrackCommand
+      addTargetWithHandler:mPreviousTrackHandler];
+  commandCenter.playCommand.enabled = true;
+  [commandCenter.playCommand addTargetWithHandler:mPlayHandler];
+  commandCenter.pauseCommand.enabled = true;
+  [commandCenter.pauseCommand addTargetWithHandler:mPauseHandler];
+}
+
+void MediaHardwareKeysEventSourceMacMediaCenter::EndListeningForEvents() {
+  MPNowPlayingInfoCenter* center = [MPNowPlayingInfoCenter defaultCenter];
+  center.playbackState = MPNowPlayingPlaybackStatePaused;
+  center.nowPlayingInfo = nil;
+  MPRemoteCommandCenter* commandCenter =
+      [MPRemoteCommandCenter sharedCommandCenter];
+  commandCenter.togglePlayPauseCommand.enabled = false;
+  [commandCenter.togglePlayPauseCommand removeTarget:nil];
+  commandCenter.nextTrackCommand.enabled = false;
+  [commandCenter.nextTrackCommand removeTarget:nil];
+  commandCenter.previousTrackCommand.enabled = false;
+  [commandCenter.previousTrackCommand removeTarget:nil];
+  commandCenter.playCommand.enabled = false;
+  [commandCenter.playCommand removeTarget:nil];
+  commandCenter.pauseCommand.enabled = false;
+  [commandCenter.pauseCommand removeTarget:nil];
+}
+
+bool MediaHardwareKeysEventSourceMacMediaCenter::Open() {
+  LOG("Open MediaHardwareKeysEventSourceMacMediaCenter");
+  mOpened = true;
+  BeginListeningForEvents();
+  return true;
+}
+
+void MediaHardwareKeysEventSourceMacMediaCenter::Close() {
+  LOG("Close MediaHardwareKeysEventSourceMacMediaCenter");
+  SetPlaybackState(dom::MediaSessionPlaybackState::None);
+  EndListeningForEvents();
+  mOpened = false;
+  MediaControlKeySource::Close();
+}
+
+bool MediaHardwareKeysEventSourceMacMediaCenter::IsOpened() const {
+  return mOpened;
+}
+
+void MediaHardwareKeysEventSourceMacMediaCenter::HandleEvent(
+    MediaControlKey aEvent) {
+  for (auto iter = mListeners.begin(); iter != mListeners.end(); ++iter) {
+    (*iter)->OnActionPerformed(MediaControlAction(aEvent));
+  }
+}
+
+void MediaHardwareKeysEventSourceMacMediaCenter::SetPlaybackState(
+    MediaSessionPlaybackState aState) {
+  MPNowPlayingInfoCenter* center = [MPNowPlayingInfoCenter defaultCenter];
+  if (aState == MediaSessionPlaybackState::Playing) {
+    center.playbackState = MPNowPlayingPlaybackStatePlaying;
+  } else if (aState == MediaSessionPlaybackState::Paused) {
+    center.playbackState = MPNowPlayingPlaybackStatePaused;
+  } else if (aState == MediaSessionPlaybackState::None) {
+    center.playbackState = MPNowPlayingPlaybackStateStopped;
+  }
+  MediaControlKeySource::SetPlaybackState(aState);
+}
+
+void MediaHardwareKeysEventSourceMacMediaCenter::SetMediaMetadata(
+    const dom::MediaMetadataBase& aMetadata) {
+  NSMutableDictionary* nowPlayingInfo = [NSMutableDictionary dictionary];
+  [nowPlayingInfo setObject:nsCocoaUtils::ToNSString(aMetadata.mTitle)
+                     forKey:MPMediaItemPropertyTitle];
+  [nowPlayingInfo setObject:nsCocoaUtils::ToNSString(aMetadata.mArtist)
+                     forKey:MPMediaItemPropertyArtist];
+  [nowPlayingInfo setObject:nsCocoaUtils::ToNSString(aMetadata.mAlbum)
+                     forKey:MPMediaItemPropertyAlbumTitle];
+  // The procedure of updating `nowPlayingInfo` is actually an async operation
+  // from our testing, Apple's documentation doesn't mention that though. So be
+  // aware that checking `nowPlayingInfo` immedately after setting it might not
+  // yield the expected result.
+  [MPNowPlayingInfoCenter defaultCenter].nowPlayingInfo = nowPlayingInfo;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/cocoa/MediaKeysEventSourceFactory.cpp b/widget/cocoa/MediaKeysEventSourceFactory.cpp
new file mode 100644
index 0000000000..5751a716df
--- /dev/null
+++ b/widget/cocoa/MediaKeysEventSourceFactory.cpp
@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaKeysEventSourceFactory.h"
+
+#include "MediaHardwareKeysEventSourceMac.h"
+#include "MediaHardwareKeysEventSourceMacMediaCenter.h"
+
+namespace mozilla {
+namespace widget {
+
+mozilla::dom::MediaControlKeySource* CreateMediaControlKeySource() {
+  return new MediaHardwareKeysEventSourceMacMediaCenter();
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/cocoa/NativeKeyBindings.h b/widget/cocoa/NativeKeyBindings.h
new file mode 100644
index 0000000000..6ab885fd95
--- /dev/null
+++ b/widget/cocoa/NativeKeyBindings.h
@@ -0,0 +1,67 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NativeKeyBindings_h
+#define NativeKeyBindings_h
+
+#include "mozilla/Attributes.h"
+#include "mozilla/EventForwards.h"
+#include "nsTHashMap.h"
+#include "nsIWidget.h"
+
+struct objc_selector;
+
+namespace mozilla {
+enum class NativeKeyBindingsType : uint8_t;
+
+class WritingMode;
+template <typename T>
+class Maybe;
+
+namespace widget {
+
+typedef nsTHashMap<nsPtrHashKey<objc_selector>, Command>
+    SelectorCommandHashtable;
+
+class NativeKeyBindings final {
+ public:
+  static NativeKeyBindings* GetInstance(NativeKeyBindingsType aType);
+  static void Shutdown();
+
+  /**
+   * GetEditCommandsForTests() returns commands performed in native widget
+   * in typical environment.  I.e., this does NOT refer customized shortcut
+   * key mappings of the environment.
+   */
+  static void GetEditCommandsForTests(NativeKeyBindingsType aType,
+                                      const WidgetKeyboardEvent& aEvent,
+                                      const Maybe<WritingMode>& aWritingMode,
+                                      nsTArray<CommandInt>& aCommands);
+
+  void Init(NativeKeyBindingsType aType);
+
+  void GetEditCommands(const WidgetKeyboardEvent& aEvent,
+                       const Maybe<WritingMode>& aWritingMode,
+                       nsTArray<CommandInt>& aCommands);
+
+ private:
+  NativeKeyBindings();
+
+  void AppendEditCommandsForSelector(objc_selector* aSelector,
+                                     nsTArray<CommandInt>& aCommands) const;
+
+  void LogEditCommands(const nsTArray<CommandInt>& aCommands,
+                       const char* aDescription) const;
+
+  SelectorCommandHashtable mSelectorToCommand;
+
+  static NativeKeyBindings* sInstanceForSingleLineEditor;
+  static NativeKeyBindings* sInstanceForMultiLineEditor;
+};  // NativeKeyBindings
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // NativeKeyBindings_h
diff --git a/widget/cocoa/NativeKeyBindings.mm b/widget/cocoa/NativeKeyBindings.mm
new file mode 100644
index 0000000000..e4bdf715e2
--- /dev/null
+++ b/widget/cocoa/NativeKeyBindings.mm
@@ -0,0 +1,655 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "NativeKeyBindings.h"
+
+#include "nsTArray.h"
+#include "nsCocoaUtils.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/WritingModes.h"
+
+#import <Cocoa/Cocoa.h>
+#import <Carbon/Carbon.h>
+
+namespace mozilla {
+namespace widget {
+
+static LazyLogModule gNativeKeyBindingsLog("NativeKeyBindings");
+
+NativeKeyBindings* NativeKeyBindings::sInstanceForSingleLineEditor = nullptr;
+NativeKeyBindings* NativeKeyBindings::sInstanceForMultiLineEditor = nullptr;
+
+// static
+NativeKeyBindings* NativeKeyBindings::GetInstance(NativeKeyBindingsType aType) {
+  switch (aType) {
+    case NativeKeyBindingsType::SingleLineEditor:
+      if (!sInstanceForSingleLineEditor) {
+        sInstanceForSingleLineEditor = new NativeKeyBindings();
+        sInstanceForSingleLineEditor->Init(aType);
+      }
+      return sInstanceForSingleLineEditor;
+    case NativeKeyBindingsType::MultiLineEditor:
+    case NativeKeyBindingsType::RichTextEditor:
+      if (!sInstanceForMultiLineEditor) {
+        sInstanceForMultiLineEditor = new NativeKeyBindings();
+        sInstanceForMultiLineEditor->Init(aType);
+      }
+      return sInstanceForMultiLineEditor;
+    default:
+      MOZ_CRASH("Not implemented");
+      return nullptr;
+  }
+}
+
+// static
+void NativeKeyBindings::Shutdown() {
+  delete sInstanceForSingleLineEditor;
+  sInstanceForSingleLineEditor = nullptr;
+  delete sInstanceForMultiLineEditor;
+  sInstanceForMultiLineEditor = nullptr;
+}
+
+NativeKeyBindings::NativeKeyBindings() {}
+
+inline objc_selector* ToObjcSelectorPtr(SEL aSel) {
+  return reinterpret_cast<objc_selector*>(aSel);
+}
+#define SEL_TO_COMMAND(aSel, aCommand)                                  \
+  mSelectorToCommand.InsertOrUpdate(ToObjcSelectorPtr(@selector(aSel)), \
+                                    aCommand)
+
+void NativeKeyBindings::Init(NativeKeyBindingsType aType) {
+  MOZ_LOG(gNativeKeyBindingsLog, LogLevel::Info,
+          ("%p NativeKeyBindings::Init", this));
+
+  // Many selectors have a one-to-one mapping to a Gecko command. Those mappings
+  // are registered in mSelectorToCommand.
+
+  // Selectors from NSResponder's "Responding to Action Messages" section and
+  // from NSText's "Action Methods for Editing" section
+
+  // TODO: Improves correctness of left / right meaning
+  // TODO: Add real paragraph motions
+
+  // SEL_TO_COMMAND(cancelOperation:, );
+  // SEL_TO_COMMAND(capitalizeWord:, );
+  // SEL_TO_COMMAND(centerSelectionInVisibleArea:, );
+  // SEL_TO_COMMAND(changeCaseOfLetter:, );
+  // SEL_TO_COMMAND(complete:, );
+  SEL_TO_COMMAND(copy:, Command::Copy);
+  // SEL_TO_COMMAND(copyFont:, );
+  // SEL_TO_COMMAND(copyRuler:, );
+  SEL_TO_COMMAND(cut:, Command::Cut);
+  SEL_TO_COMMAND(delete:, Command::Delete);
+  SEL_TO_COMMAND(deleteBackward:, Command::DeleteCharBackward);
+  // SEL_TO_COMMAND(deleteBackwardByDecomposingPreviousCharacter:, );
+  SEL_TO_COMMAND(deleteForward:, Command::DeleteCharForward);
+
+  // TODO: deleteTo* selectors are also supposed to add text to a kill buffer
+  SEL_TO_COMMAND(deleteToBeginningOfLine:, Command::DeleteToBeginningOfLine);
+  SEL_TO_COMMAND(deleteToBeginningOfParagraph:,
+                 Command::DeleteToBeginningOfLine);
+  SEL_TO_COMMAND(deleteToEndOfLine:, Command::DeleteToEndOfLine);
+  SEL_TO_COMMAND(deleteToEndOfParagraph:, Command::DeleteToEndOfLine);
+  // SEL_TO_COMMAND(deleteToMark:, );
+
+  SEL_TO_COMMAND(deleteWordBackward:, Command::DeleteWordBackward);
+  SEL_TO_COMMAND(deleteWordForward:, Command::DeleteWordForward);
+  // SEL_TO_COMMAND(indent:, );
+  // SEL_TO_COMMAND(insertBacktab:, );
+  // SEL_TO_COMMAND(insertContainerBreak:, );
+  // SEL_TO_COMMAND(insertLineBreak:, );
+  // SEL_TO_COMMAND(insertNewline:, );
+  // SEL_TO_COMMAND(insertNewlineIgnoringFieldEditor:, );
+  // SEL_TO_COMMAND(insertParagraphSeparator:, );
+  // SEL_TO_COMMAND(insertTab:, );
+  // SEL_TO_COMMAND(insertTabIgnoringFieldEditor:, );
+  // SEL_TO_COMMAND(insertDoubleQuoteIgnoringSubstitution:, );
+  // SEL_TO_COMMAND(insertSingleQuoteIgnoringSubstitution:, );
+  // SEL_TO_COMMAND(lowercaseWord:, );
+  SEL_TO_COMMAND(moveBackward:, Command::CharPrevious);
+  SEL_TO_COMMAND(moveBackwardAndModifySelection:, Command::SelectCharPrevious);
+  if (aType == NativeKeyBindingsType::SingleLineEditor) {
+    SEL_TO_COMMAND(moveDown:, Command::EndLine);
+  } else {
+    SEL_TO_COMMAND(moveDown:, Command::LineNext);
+  }
+  SEL_TO_COMMAND(moveDownAndModifySelection:, Command::SelectLineNext);
+  SEL_TO_COMMAND(moveForward:, Command::CharNext);
+  SEL_TO_COMMAND(moveForwardAndModifySelection:, Command::SelectCharNext);
+  SEL_TO_COMMAND(moveLeft:, Command::CharPrevious);
+  SEL_TO_COMMAND(moveLeftAndModifySelection:, Command::SelectCharPrevious);
+  SEL_TO_COMMAND(moveParagraphBackwardAndModifySelection:,
+                 Command::SelectBeginLine);
+  SEL_TO_COMMAND(moveParagraphForwardAndModifySelection:,
+                 Command::SelectEndLine);
+  SEL_TO_COMMAND(moveRight:, Command::CharNext);
+  SEL_TO_COMMAND(moveRightAndModifySelection:, Command::SelectCharNext);
+  SEL_TO_COMMAND(moveToBeginningOfDocument:, Command::MoveTop);
+  SEL_TO_COMMAND(moveToBeginningOfDocumentAndModifySelection:,
+                 Command::SelectTop);
+  SEL_TO_COMMAND(moveToBeginningOfLine:, Command::BeginLine);
+  SEL_TO_COMMAND(moveToBeginningOfLineAndModifySelection:,
+                 Command::SelectBeginLine);
+  SEL_TO_COMMAND(moveToBeginningOfParagraph:, Command::BeginLine);
+  SEL_TO_COMMAND(moveToBeginningOfParagraphAndModifySelection:,
+                 Command::SelectBeginLine);
+  SEL_TO_COMMAND(moveToEndOfDocument:, Command::MoveBottom);
+  SEL_TO_COMMAND(moveToEndOfDocumentAndModifySelection:, Command::SelectBottom);
+  SEL_TO_COMMAND(moveToEndOfLine:, Command::EndLine);
+  SEL_TO_COMMAND(moveToEndOfLineAndModifySelection:, Command::SelectEndLine);
+  SEL_TO_COMMAND(moveToEndOfParagraph:, Command::EndLine);
+  SEL_TO_COMMAND(moveToEndOfParagraphAndModifySelection:,
+                 Command::SelectEndLine);
+  SEL_TO_COMMAND(moveToLeftEndOfLine:, Command::BeginLine);
+  SEL_TO_COMMAND(moveToLeftEndOfLineAndModifySelection:,
+                 Command::SelectBeginLine);
+  SEL_TO_COMMAND(moveToRightEndOfLine:, Command::EndLine);
+  SEL_TO_COMMAND(moveToRightEndOfLineAndModifySelection:,
+                 Command::SelectEndLine);
+  if (aType == NativeKeyBindingsType::SingleLineEditor) {
+    SEL_TO_COMMAND(moveUp:, Command::BeginLine);
+  } else {
+    SEL_TO_COMMAND(moveUp:, Command::LinePrevious);
+  }
+  SEL_TO_COMMAND(moveUpAndModifySelection:, Command::SelectLinePrevious);
+  SEL_TO_COMMAND(moveWordBackward:, Command::WordPrevious);
+  SEL_TO_COMMAND(moveWordBackwardAndModifySelection:,
+                 Command::SelectWordPrevious);
+  SEL_TO_COMMAND(moveWordForward:, Command::WordNext);
+  SEL_TO_COMMAND(moveWordForwardAndModifySelection:, Command::SelectWordNext);
+  SEL_TO_COMMAND(moveWordLeft:, Command::WordPrevious);
+  SEL_TO_COMMAND(moveWordLeftAndModifySelection:, Command::SelectWordPrevious);
+  SEL_TO_COMMAND(moveWordRight:, Command::WordNext);
+  SEL_TO_COMMAND(moveWordRightAndModifySelection:, Command::SelectWordNext);
+  SEL_TO_COMMAND(pageDown:, Command::MovePageDown);
+  SEL_TO_COMMAND(pageDownAndModifySelection:, Command::SelectPageDown);
+  SEL_TO_COMMAND(pageUp:, Command::MovePageUp);
+  SEL_TO_COMMAND(pageUpAndModifySelection:, Command::SelectPageUp);
+  SEL_TO_COMMAND(paste:, Command::Paste);
+  // SEL_TO_COMMAND(pasteFont:, );
+  // SEL_TO_COMMAND(pasteRuler:, );
+  SEL_TO_COMMAND(scrollLineDown:, Command::ScrollLineDown);
+  SEL_TO_COMMAND(scrollLineUp:, Command::ScrollLineUp);
+  SEL_TO_COMMAND(scrollPageDown:, Command::ScrollPageDown);
+  SEL_TO_COMMAND(scrollPageUp:, Command::ScrollPageUp);
+  SEL_TO_COMMAND(scrollToBeginningOfDocument:, Command::ScrollTop);
+  SEL_TO_COMMAND(scrollToEndOfDocument:, Command::ScrollBottom);
+  SEL_TO_COMMAND(selectAll:, Command::SelectAll);
+  // selectLine: is complex, see KeyDown
+  if (aType == NativeKeyBindingsType::SingleLineEditor) {
+    SEL_TO_COMMAND(selectParagraph:, Command::SelectAll);
+  }
+  // SEL_TO_COMMAND(selectToMark:, );
+  // selectWord: is complex, see KeyDown
+  // SEL_TO_COMMAND(setMark:, );
+  // SEL_TO_COMMAND(showContextHelp:, );
+  // SEL_TO_COMMAND(supplementalTargetForAction:sender:, );
+  // SEL_TO_COMMAND(swapWithMark:, );
+  // SEL_TO_COMMAND(transpose:, );
+  // SEL_TO_COMMAND(transposeWords:, );
+  // SEL_TO_COMMAND(uppercaseWord:, );
+  // SEL_TO_COMMAND(yank:, );
+}
+
+#undef SEL_TO_COMMAND
+
+void NativeKeyBindings::GetEditCommands(const WidgetKeyboardEvent& aEvent,
+                                        const Maybe<WritingMode>& aWritingMode,
+                                        nsTArray<CommandInt>& aCommands) {
+  MOZ_ASSERT(!aEvent.mFlags.mIsSynthesizedForTests);
+  MOZ_ASSERT(aCommands.IsEmpty());
+
+  MOZ_LOG(gNativeKeyBindingsLog, LogLevel::Info,
+          ("%p NativeKeyBindings::GetEditCommands", this));
+
+  // Recover the current event, which should always be the key down we are
+  // responding to.
+
+  NSEvent* cocoaEvent = reinterpret_cast<NSEvent*>(aEvent.mNativeKeyEvent);
+
+  if (!cocoaEvent || [cocoaEvent type] != NSEventTypeKeyDown) {
+    MOZ_LOG(gNativeKeyBindingsLog, LogLevel::Info,
+            ("%p NativeKeyBindings::GetEditCommands, no Cocoa key down event",
+             this));
+
+    return;
+  }
+
+  if (aWritingMode.isSome() && aEvent.NeedsToRemapNavigationKey() &&
+      aWritingMode.ref().IsVertical()) {
+    NSEvent* originalEvent = cocoaEvent;
+
+    // TODO: Use KeyNameIndex rather than legacy keyCode.
+    uint32_t remappedGeckoKeyCode =
+        aEvent.GetRemappedKeyCode(aWritingMode.ref());
+    uint32_t remappedCocoaKeyCode = 0;
+    switch (remappedGeckoKeyCode) {
+      case NS_VK_UP:
+        remappedCocoaKeyCode = kVK_UpArrow;
+        break;
+      case NS_VK_DOWN:
+        remappedCocoaKeyCode = kVK_DownArrow;
+        break;
+      case NS_VK_LEFT:
+        remappedCocoaKeyCode = kVK_LeftArrow;
+        break;
+      case NS_VK_RIGHT:
+        remappedCocoaKeyCode = kVK_RightArrow;
+        break;
+      default:
+        MOZ_ASSERT_UNREACHABLE("Add a case for the new remapped key");
+        return;
+    }
+    unichar ch =
+        nsCocoaUtils::ConvertGeckoKeyCodeToMacCharCode(remappedGeckoKeyCode);
+    NSString* chars = [[[NSString alloc] initWithCharacters:&ch
+                                                     length:1] autorelease];
+    cocoaEvent = [NSEvent keyEventWithType:[originalEvent type]
+                                  location:[originalEvent locationInWindow]
+                             modifierFlags:[originalEvent modifierFlags]
+                                 timestamp:[originalEvent timestamp]
+                              windowNumber:[originalEvent windowNumber]
+                                   context:nil
+                                characters:chars
+               charactersIgnoringModifiers:chars
+                                 isARepeat:[originalEvent isARepeat]
+                                   keyCode:remappedCocoaKeyCode];
+  }
+
+  MOZ_LOG(gNativeKeyBindingsLog, LogLevel::Info,
+          ("%p NativeKeyBindings::GetEditCommands, interpreting", this));
+
+  AutoTArray<KeyBindingsCommand, 2> bindingCommands;
+  nsCocoaUtils::GetCommandsFromKeyEvent(cocoaEvent, bindingCommands);
+
+  MOZ_LOG(gNativeKeyBindingsLog, LogLevel::Info,
+          ("%p NativeKeyBindings::GetEditCommands, bindingCommands=%zu", this,
+           bindingCommands.Length()));
+
+  for (uint32_t i = 0; i < bindingCommands.Length(); i++) {
+    SEL selector = bindingCommands[i].selector;
+
+    if (MOZ_LOG_TEST(gNativeKeyBindingsLog, LogLevel::Info)) {
+      NSString* selectorString = NSStringFromSelector(selector);
+      nsAutoString nsSelectorString;
+      nsCocoaUtils::GetStringForNSString(selectorString, nsSelectorString);
+
+      MOZ_LOG(gNativeKeyBindingsLog, LogLevel::Info,
+              ("%p NativeKeyBindings::GetEditCommands, selector=%s", this,
+               NS_LossyConvertUTF16toASCII(nsSelectorString).get()));
+    }
+
+    AppendEditCommandsForSelector(ToObjcSelectorPtr(selector), aCommands);
+  }
+
+  LogEditCommands(aCommands, "NativeKeyBindings::GetEditCommands");
+}
+
+void NativeKeyBindings::AppendEditCommandsForSelector(
+    objc_selector* aSelector, nsTArray<CommandInt>& aCommands) const {
+  // Try to find a simple mapping in the hashtable
+  Command geckoCommand = Command::DoNothing;
+  if (mSelectorToCommand.Get(aSelector, &geckoCommand) &&
+      geckoCommand != Command::DoNothing) {
+    aCommands.AppendElement(static_cast<CommandInt>(geckoCommand));
+  } else if (aSelector == ToObjcSelectorPtr(@selector(selectLine:))) {
+    // This is functional, but Cocoa's version is direction-less in that
+    // selection direction is not determined until some future directed action
+    // is taken. See bug 282097, comment 79 for more details.
+    aCommands.AppendElement(static_cast<CommandInt>(Command::BeginLine));
+    aCommands.AppendElement(static_cast<CommandInt>(Command::SelectEndLine));
+  } else if (aSelector == ToObjcSelectorPtr(@selector(selectWord:))) {
+    // This is functional, but Cocoa's version is direction-less in that
+    // selection direction is not determined until some future directed action
+    // is taken. See bug 282097, comment 79 for more details.
+    aCommands.AppendElement(static_cast<CommandInt>(Command::WordPrevious));
+    aCommands.AppendElement(static_cast<CommandInt>(Command::SelectWordNext));
+  }
+}
+
+void NativeKeyBindings::LogEditCommands(const nsTArray<CommandInt>& aCommands,
+                                        const char* aDescription) const {
+  if (!MOZ_LOG_TEST(gNativeKeyBindingsLog, LogLevel::Info)) {
+    return;
+  }
+
+  if (aCommands.IsEmpty()) {
+    MOZ_LOG(gNativeKeyBindingsLog, LogLevel::Info,
+            ("%p %s, no edit commands", this, aDescription));
+    return;
+  }
+
+  for (CommandInt commandInt : aCommands) {
+    Command geckoCommand = static_cast<Command>(commandInt);
+    MOZ_LOG(gNativeKeyBindingsLog, LogLevel::Info,
+            ("%p %s, command=%s", this, aDescription,
+             WidgetKeyboardEvent::GetCommandStr(geckoCommand)));
+  }
+}
+
+// static
+void NativeKeyBindings::GetEditCommandsForTests(
+    NativeKeyBindingsType aType, const WidgetKeyboardEvent& aEvent,
+    const Maybe<WritingMode>& aWritingMode, nsTArray<CommandInt>& aCommands) {
+  MOZ_DIAGNOSTIC_ASSERT(aEvent.IsTrusted());
+
+  // The following mapping is checked on Big Sur. Some of them are defined in:
+  // https://support.apple.com/en-us/HT201236#text
+  NativeKeyBindings* instance = NativeKeyBindings::GetInstance(aType);
+  if (NS_WARN_IF(!instance)) {
+    return;
+  }
+  switch (aWritingMode.isSome()
+              ? aEvent.GetRemappedKeyNameIndex(aWritingMode.ref())
+              : aEvent.mKeyNameIndex) {
+    case KEY_NAME_INDEX_USE_STRING:
+      if (!aEvent.IsControl() || aEvent.IsAlt() || aEvent.IsMeta()) {
+        break;
+      }
+      switch (aEvent.PseudoCharCode()) {
+        case 'a':
+        case 'A':
+          instance->AppendEditCommandsForSelector(
+              !aEvent.IsShift()
+                  ? ToObjcSelectorPtr(@selector(moveToBeginningOfParagraph:))
+                  : ToObjcSelectorPtr(@selector(
+                        moveToBeginningOfParagraphAndModifySelection:)),
+              aCommands);
+          break;
+        case 'b':
+        case 'B':
+          instance->AppendEditCommandsForSelector(
+              !aEvent.IsShift() ? ToObjcSelectorPtr(@selector(moveBackward:))
+                                : ToObjcSelectorPtr(@selector(
+                                      moveBackwardAndModifySelection:)),
+              aCommands);
+          break;
+        case 'd':
+        case 'D':
+          if (!aEvent.IsShift()) {
+            instance->AppendEditCommandsForSelector(
+                ToObjcSelectorPtr(@selector(deleteForward:)), aCommands);
+          }
+          break;
+        case 'e':
+        case 'E':
+          instance->AppendEditCommandsForSelector(
+              !aEvent.IsShift()
+                  ? ToObjcSelectorPtr(@selector(moveToEndOfParagraph:))
+                  : ToObjcSelectorPtr(
+                        @selector(moveToEndOfParagraphAndModifySelection:)),
+              aCommands);
+          break;
+        case 'f':
+        case 'F':
+          instance->AppendEditCommandsForSelector(
+              !aEvent.IsShift() ? ToObjcSelectorPtr(@selector(moveForward:))
+                                : ToObjcSelectorPtr(@selector(
+                                      moveForwardAndModifySelection:)),
+              aCommands);
+          break;
+        case 'h':
+        case 'H':
+          if (!aEvent.IsShift()) {
+            instance->AppendEditCommandsForSelector(
+                ToObjcSelectorPtr(@selector(deleteBackward:)), aCommands);
+          }
+          break;
+        case 'k':
+        case 'K':
+          if (!aEvent.IsShift()) {
+            instance->AppendEditCommandsForSelector(
+                ToObjcSelectorPtr(@selector(deleteToEndOfParagraph:)),
+                aCommands);
+          }
+          break;
+        case 'n':
+        case 'N':
+          instance->AppendEditCommandsForSelector(
+              !aEvent.IsShift()
+                  ? ToObjcSelectorPtr(@selector(moveDown:))
+                  : ToObjcSelectorPtr(@selector(moveDownAndModifySelection:)),
+              aCommands);
+          break;
+        case 'p':
+        case 'P':
+          instance->AppendEditCommandsForSelector(
+              !aEvent.IsShift()
+                  ? ToObjcSelectorPtr(@selector(moveUp:))
+                  : ToObjcSelectorPtr(@selector(moveUpAndModifySelection:)),
+              aCommands);
+          break;
+        default:
+          break;
+      }
+      break;
+    case KEY_NAME_INDEX_Backspace:
+      if (aEvent.IsMeta()) {
+        if (aEvent.IsAlt() || aEvent.IsControl()) {
+          break;
+        }
+        // Shift is ignored.
+        instance->AppendEditCommandsForSelector(
+            ToObjcSelectorPtr(@selector(deleteToBeginningOfLine:)), aCommands);
+        break;
+      }
+      if (aEvent.IsAlt()) {
+        // Shift and Control are ignored.
+        instance->AppendEditCommandsForSelector(
+            ToObjcSelectorPtr(@selector(deleteWordBackward:)), aCommands);
+        break;
+      }
+      if (aEvent.IsControl()) {
+        if (aEvent.IsShift()) {
+          instance->AppendEditCommandsForSelector(
+              ToObjcSelectorPtr(
+                  @selector(deleteBackwardByDecomposingPreviousCharacter:)),
+              aCommands);
+        }
+        break;
+      }
+      // Shift is ignored.
+      instance->AppendEditCommandsForSelector(
+          ToObjcSelectorPtr(@selector(deleteBackward:)), aCommands);
+      break;
+    case KEY_NAME_INDEX_Delete:
+      if (aEvent.IsControl() || aEvent.IsMeta()) {
+        break;
+      }
+      if (aEvent.IsAlt()) {
+        // Shift is ignored.
+        instance->AppendEditCommandsForSelector(
+            ToObjcSelectorPtr(@selector(deleteWordForward:)), aCommands);
+        break;
+      }
+      // Shift is ignored.
+      instance->AppendEditCommandsForSelector(
+          ToObjcSelectorPtr(@selector(deleteForward:)), aCommands);
+      break;
+    case KEY_NAME_INDEX_PageDown:
+      if (aEvent.IsControl() || aEvent.IsMeta()) {
+        break;
+      }
+      if (aEvent.IsAlt()) {
+        // Shift is ignored.
+        instance->AppendEditCommandsForSelector(
+            ToObjcSelectorPtr(@selector(pageDown:)), aCommands);
+        break;
+      }
+      instance->AppendEditCommandsForSelector(
+          !aEvent.IsShift()
+              ? ToObjcSelectorPtr(@selector(scrollPageDown:))
+              : ToObjcSelectorPtr(@selector(pageDownAndModifySelection:)),
+          aCommands);
+      break;
+    case KEY_NAME_INDEX_PageUp:
+      if (aEvent.IsControl() || aEvent.IsMeta()) {
+        break;
+      }
+      if (aEvent.IsAlt()) {
+        // Shift is ignored.
+        instance->AppendEditCommandsForSelector(
+            ToObjcSelectorPtr(@selector(pageUp:)), aCommands);
+        break;
+      }
+      instance->AppendEditCommandsForSelector(
+          !aEvent.IsShift()
+              ? ToObjcSelectorPtr(@selector(scrollPageUp:))
+              : ToObjcSelectorPtr(@selector(pageUpAndModifySelection:)),
+          aCommands);
+      break;
+    case KEY_NAME_INDEX_Home:
+      if (aEvent.IsAlt() || aEvent.IsControl() || aEvent.IsMeta()) {
+        break;
+      }
+      instance->AppendEditCommandsForSelector(
+          !aEvent.IsShift()
+              ? ToObjcSelectorPtr(@selector(scrollToBeginningOfDocument:))
+              : ToObjcSelectorPtr(
+                    @selector(moveToBeginningOfDocumentAndModifySelection:)),
+          aCommands);
+      break;
+    case KEY_NAME_INDEX_End:
+      if (aEvent.IsAlt() || aEvent.IsControl() || aEvent.IsMeta()) {
+        break;
+      }
+      instance->AppendEditCommandsForSelector(
+          !aEvent.IsShift()
+              ? ToObjcSelectorPtr(@selector(scrollToEndOfDocument:))
+              : ToObjcSelectorPtr(@selector
+                                  (moveToEndOfDocumentAndModifySelection:)),
+          aCommands);
+      break;
+    case KEY_NAME_INDEX_ArrowLeft:
+      if (aEvent.IsAlt()) {
+        break;
+      }
+      if (aEvent.IsMeta() || (aEvent.IsControl() && aEvent.IsShift())) {
+        instance->AppendEditCommandsForSelector(
+            !aEvent.IsShift()
+                ? ToObjcSelectorPtr(@selector(moveToLeftEndOfLine:))
+                : ToObjcSelectorPtr(@selector
+                                    (moveToLeftEndOfLineAndModifySelection:)),
+            aCommands);
+        break;
+      }
+      if (aEvent.IsControl()) {
+        break;
+      }
+      instance->AppendEditCommandsForSelector(
+          !aEvent.IsShift()
+              ? ToObjcSelectorPtr(@selector(moveLeft:))
+              : ToObjcSelectorPtr(@selector(moveLeftAndModifySelection:)),
+          aCommands);
+      break;
+    case KEY_NAME_INDEX_ArrowRight:
+      if (aEvent.IsAlt()) {
+        break;
+      }
+      if (aEvent.IsMeta() || (aEvent.IsControl() && aEvent.IsShift())) {
+        instance->AppendEditCommandsForSelector(
+            !aEvent.IsShift()
+                ? ToObjcSelectorPtr(@selector(moveToRightEndOfLine:))
+                : ToObjcSelectorPtr(@selector
+                                    (moveToRightEndOfLineAndModifySelection:)),
+            aCommands);
+        break;
+      }
+      if (aEvent.IsControl()) {
+        break;
+      }
+      instance->AppendEditCommandsForSelector(
+          !aEvent.IsShift()
+              ? ToObjcSelectorPtr(@selector(moveRight:))
+              : ToObjcSelectorPtr(@selector(moveRightAndModifySelection:)),
+          aCommands);
+      break;
+    case KEY_NAME_INDEX_ArrowUp:
+      if (aEvent.IsControl()) {
+        break;
+      }
+      if (aEvent.IsMeta()) {
+        if (aEvent.IsAlt()) {
+          break;
+        }
+        instance->AppendEditCommandsForSelector(
+            !aEvent.IsShift()
+                ? ToObjcSelectorPtr(@selector(moveToBeginningOfDocument:))
+                : ToObjcSelectorPtr(
+                      @selector(moveToBegginingOfDocumentAndModifySelection:)),
+            aCommands);
+        break;
+      }
+      if (aEvent.IsAlt()) {
+        if (!aEvent.IsShift()) {
+          instance->AppendEditCommandsForSelector(
+              ToObjcSelectorPtr(@selector(moveBackward:)), aCommands);
+          instance->AppendEditCommandsForSelector(
+              ToObjcSelectorPtr(@selector(moveToBeginningOfParagraph:)),
+              aCommands);
+          break;
+        }
+        instance->AppendEditCommandsForSelector(
+            ToObjcSelectorPtr(@selector
+                              (moveParagraphBackwardAndModifySelection:)),
+            aCommands);
+        break;
+      }
+      instance->AppendEditCommandsForSelector(
+          !aEvent.IsShift()
+              ? ToObjcSelectorPtr(@selector(moveUp:))
+              : ToObjcSelectorPtr(@selector(moveUpAndModifySelection:)),
+          aCommands);
+      break;
+    case KEY_NAME_INDEX_ArrowDown:
+      if (aEvent.IsControl()) {
+        break;
+      }
+      if (aEvent.IsMeta()) {
+        if (aEvent.IsAlt()) {
+          break;
+        }
+        instance->AppendEditCommandsForSelector(
+            !aEvent.IsShift()
+                ? ToObjcSelectorPtr(@selector(moveToEndOfDocument:))
+                : ToObjcSelectorPtr(@selector
+                                    (moveToEndOfDocumentAndModifySelection:)),
+            aCommands);
+        break;
+      }
+      if (aEvent.IsAlt()) {
+        if (!aEvent.IsShift()) {
+          instance->AppendEditCommandsForSelector(
+              ToObjcSelectorPtr(@selector(moveForward:)), aCommands);
+          instance->AppendEditCommandsForSelector(
+              ToObjcSelectorPtr(@selector(moveToEndOfParagraph:)), aCommands);
+          break;
+        }
+        instance->AppendEditCommandsForSelector(
+            ToObjcSelectorPtr(@selector
+                              (moveParagraphForwardAndModifySelection:)),
+            aCommands);
+        break;
+      }
+      instance->AppendEditCommandsForSelector(
+          !aEvent.IsShift()
+              ? ToObjcSelectorPtr(@selector(moveDown:))
+              : ToObjcSelectorPtr(@selector(moveDownAndModifySelection:)),
+          aCommands);
+      break;
+    default:
+      break;
+  }
+
+  instance->LogEditCommands(aCommands,
+                            "NativeKeyBindings::GetEditCommandsForTests");
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/cocoa/NativeMenuMac.h b/widget/cocoa/NativeMenuMac.h
new file mode 100644
index 0000000000..e230fd184c
--- /dev/null
+++ b/widget/cocoa/NativeMenuMac.h
@@ -0,0 +1,94 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NativeMenuMac_h
+#define NativeMenuMac_h
+
+#include "mozilla/widget/NativeMenu.h"
+
+#include "nsMenuItemIconX.h"
+#include "nsMenuX.h"
+
+class nsIContent;
+class nsMenuGroupOwnerX;
+
+namespace mozilla {
+
+namespace dom {
+class Element;
+}
+
+namespace widget {
+
+class NativeMenuMac : public NativeMenu,
+                      public nsMenuItemIconX::Listener,
+                      public nsMenuX::Observer {
+ public:
+  explicit NativeMenuMac(dom::Element* aElement);
+
+  // NativeMenu
+  void ShowAsContextMenu(nsIFrame* aClickedFrame, const CSSIntPoint& aPosition,
+                         bool aIsContextMenu) override;
+  bool Close() override;
+  void ActivateItem(dom::Element* aItemElement, Modifiers aModifiers,
+                    int16_t aButton, ErrorResult& aRv) override;
+  void OpenSubmenu(dom::Element* aMenuElement) override;
+  void CloseSubmenu(dom::Element* aMenuElement) override;
+  RefPtr<dom::Element> Element() override;
+  void AddObserver(NativeMenu::Observer* aObserver) override {
+    mObservers.AppendElement(aObserver);
+  }
+  void RemoveObserver(NativeMenu::Observer* aObserver) override {
+    mObservers.RemoveElement(aObserver);
+  }
+
+  // nsMenuItemIconX::Listener
+  void IconUpdated() override;
+
+  // nsMenuX::Observer
+  void OnMenuWillOpen(dom::Element* aPopupElement) override;
+  void OnMenuDidOpen(dom::Element* aPopupElement) override;
+  void OnMenuWillActivateItem(dom::Element* aPopupElement,
+                              dom::Element* aMenuItemElement) override;
+  void OnMenuClosed(dom::Element* aPopupElement) override;
+
+  NSMenu* NativeNSMenu() { return mMenu ? mMenu->NativeNSMenu() : nil; }
+  void MenuWillOpen();
+
+  // Returns whether a menu item was found at the specified path.
+  bool ActivateNativeMenuItemAt(const nsAString& aIndexString);
+
+  void ForceUpdateNativeMenuAt(const nsAString& aIndexString);
+  void Dump();
+
+  // If this menu is the menu of a system status bar item (NSStatusItem),
+  // let the menu know about the status item so that it can propagate
+  // any icon changes to the status item.
+  void SetContainerStatusBarItem(NSStatusItem* aItem);
+
+ protected:
+  virtual ~NativeMenuMac();
+
+  // Find the deepest nsMenuX which contains aElement, only descending into open
+  // menus.
+  // Returns nullptr if the element was not found or if the menus on the path
+  // were not all open.
+  RefPtr<nsMenuX> GetOpenMenuContainingElement(dom::Element* aElement);
+
+  RefPtr<dom::Element> mElement;
+  RefPtr<nsMenuGroupOwnerX> mMenuGroupOwner;
+  RefPtr<nsMenuX> mMenu;
+  nsTArray<NativeMenu::Observer*> mObservers;
+  NSStatusItem* mContainerStatusBarItem;
+
+  // Non-zero after a call to ShowAsContextMenu. Stores the handle from the
+  // MOZMenuOpeningCoordinator.
+  NSInteger mOpeningHandle = 0;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/cocoa/NativeMenuMac.mm b/widget/cocoa/NativeMenuMac.mm
new file mode 100644
index 0000000000..4efa48c53f
--- /dev/null
+++ b/widget/cocoa/NativeMenuMac.mm
@@ -0,0 +1,410 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "NativeMenuMac.h"
+
+#include "mozilla/Assertions.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/BasicEvents.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/Element.h"
+
+#include "MOZMenuOpeningCoordinator.h"
+#include "nsISupports.h"
+#include "nsGkAtoms.h"
+#include "nsMenuGroupOwnerX.h"
+#include "nsMenuItemX.h"
+#include "nsMenuUtilsX.h"
+#include "nsNativeThemeColors.h"
+#include "nsObjCExceptions.h"
+#include "nsThreadUtils.h"
+#include "PresShell.h"
+#include "nsCocoaUtils.h"
+#include "nsIFrame.h"
+#include "nsPresContext.h"
+#include "nsDeviceContext.h"
+
+namespace mozilla {
+
+using dom::Element;
+
+namespace widget {
+
+NativeMenuMac::NativeMenuMac(dom::Element* aElement)
+    : mElement(aElement), mContainerStatusBarItem(nil) {
+  MOZ_RELEASE_ASSERT(
+      aElement->IsAnyOfXULElements(nsGkAtoms::menu, nsGkAtoms::menupopup));
+  mMenuGroupOwner = new nsMenuGroupOwnerX(aElement, nullptr);
+  mMenu = MakeRefPtr<nsMenuX>(nullptr, mMenuGroupOwner, aElement);
+  mMenu->SetObserver(this);
+  mMenu->SetIconListener(this);
+  mMenu->SetupIcon();
+}
+
+NativeMenuMac::~NativeMenuMac() {
+  mMenu->DetachFromGroupOwnerRecursive();
+  mMenu->ClearObserver();
+  mMenu->ClearIconListener();
+}
+
+static void UpdateMenu(nsMenuX* aMenu) {
+  aMenu->MenuOpened();
+  aMenu->MenuClosed();
+
+  uint32_t itemCount = aMenu->GetItemCount();
+  for (uint32_t i = 0; i < itemCount; i++) {
+    nsMenuX::MenuChild menuObject = *aMenu->GetItemAt(i);
+    if (menuObject.is<RefPtr<nsMenuX>>()) {
+      UpdateMenu(menuObject.as<RefPtr<nsMenuX>>());
+    }
+  }
+}
+
+void NativeMenuMac::MenuWillOpen() {
+  // Force an update on the mMenu by faking an open/close on all of
+  // its submenus.
+  UpdateMenu(mMenu.get());
+}
+
+bool NativeMenuMac::ActivateNativeMenuItemAt(const nsAString& aIndexString) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  NSMenu* menu = mMenu->NativeNSMenu();
+
+  nsMenuUtilsX::CheckNativeMenuConsistency(menu);
+
+  NSString* locationString =
+      [NSString stringWithCharacters:reinterpret_cast<const unichar*>(
+                                         aIndexString.BeginReading())
+                              length:aIndexString.Length()];
+  NSMenuItem* item =
+      nsMenuUtilsX::NativeMenuItemWithLocation(menu, locationString, false);
+
+  // We can't perform an action on an item with a submenu, that will raise
+  // an obj-c exception.
+  if (item && !item.hasSubmenu) {
+    NSMenu* parent = item.menu;
+    if (parent) {
+      // NSLog(@"Performing action for native menu item titled: %@\n",
+      //       [[currentSubmenu itemAtIndex:targetIndex] title]);
+      mozilla::AutoRestore<bool> autoRestore(
+          nsMenuUtilsX::gIsSynchronouslyActivatingNativeMenuItemDuringTest);
+      nsMenuUtilsX::gIsSynchronouslyActivatingNativeMenuItemDuringTest = true;
+      [parent performActionForItemAtIndex:[parent indexOfItem:item]];
+      return true;
+    }
+  }
+
+  return false;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void NativeMenuMac::ForceUpdateNativeMenuAt(const nsAString& aIndexString) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  NSString* locationString =
+      [NSString stringWithCharacters:reinterpret_cast<const unichar*>(
+                                         aIndexString.BeginReading())
+                              length:aIndexString.Length()];
+  NSArray<NSString*>* indexes =
+      [locationString componentsSeparatedByString:@"|"];
+  RefPtr<nsMenuX> currentMenu = mMenu.get();
+
+  // now find the correct submenu
+  unsigned int indexCount = indexes.count;
+  for (unsigned int i = 1; currentMenu && i < indexCount; i++) {
+    int targetIndex = [indexes objectAtIndex:i].intValue;
+    int visible = 0;
+    uint32_t length = currentMenu->GetItemCount();
+    for (unsigned int j = 0; j < length; j++) {
+      Maybe<nsMenuX::MenuChild> targetMenu = currentMenu->GetItemAt(j);
+      if (!targetMenu) {
+        return;
+      }
+      RefPtr<nsIContent> content = targetMenu->match(
+          [](const RefPtr<nsMenuX>& aMenu) { return aMenu->Content(); },
+          [](const RefPtr<nsMenuItemX>& aMenuItem) {
+            return aMenuItem->Content();
+          });
+      if (!nsMenuUtilsX::NodeIsHiddenOrCollapsed(content)) {
+        visible++;
+        if (targetMenu->is<RefPtr<nsMenuX>>() && visible == (targetIndex + 1)) {
+          currentMenu = targetMenu->as<RefPtr<nsMenuX>>();
+          break;
+        }
+      }
+    }
+  }
+
+  // fake open/close to cause lazy update to happen
+  currentMenu->MenuOpened();
+  currentMenu->MenuClosed();
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void NativeMenuMac::IconUpdated() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  if (mContainerStatusBarItem) {
+    NSImage* menuImage = mMenu->NativeNSMenuItem().image;
+    if (menuImage) {
+      [menuImage setTemplate:YES];
+    }
+    mContainerStatusBarItem.button.image = menuImage;
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void NativeMenuMac::SetContainerStatusBarItem(NSStatusItem* aItem) {
+  mContainerStatusBarItem = aItem;
+  IconUpdated();
+}
+
+void NativeMenuMac::Dump() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  mMenu->Dump(0);
+  nsMenuUtilsX::DumpNativeMenu(mMenu->NativeNSMenu());
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void NativeMenuMac::OnMenuWillOpen(dom::Element* aPopupElement) {
+  if (aPopupElement == mElement) {
+    return;
+  }
+
+  // Our caller isn't keeping us alive, so make sure we stay alive throughout
+  // this function in case one of the observer notifications destroys us.
+  RefPtr<NativeMenuMac> kungFuDeathGrip(this);
+
+  for (NativeMenu::Observer* observer : mObservers.Clone()) {
+    observer->OnNativeSubMenuWillOpen(aPopupElement);
+  }
+}
+
+void NativeMenuMac::OnMenuDidOpen(dom::Element* aPopupElement) {
+  // Our caller isn't keeping us alive, so make sure we stay alive throughout
+  // this function in case one of the observer notifications destroys us.
+  RefPtr<NativeMenuMac> kungFuDeathGrip(this);
+
+  for (NativeMenu::Observer* observer : mObservers.Clone()) {
+    if (aPopupElement == mElement) {
+      observer->OnNativeMenuOpened();
+    } else {
+      observer->OnNativeSubMenuDidOpen(aPopupElement);
+    }
+  }
+}
+
+void NativeMenuMac::OnMenuWillActivateItem(dom::Element* aPopupElement,
+                                           dom::Element* aMenuItemElement) {
+  // Our caller isn't keeping us alive, so make sure we stay alive throughout
+  // this function in case one of the observer notifications destroys us.
+  RefPtr<NativeMenuMac> kungFuDeathGrip(this);
+
+  for (NativeMenu::Observer* observer : mObservers.Clone()) {
+    observer->OnNativeMenuWillActivateItem(aMenuItemElement);
+  }
+}
+
+void NativeMenuMac::OnMenuClosed(dom::Element* aPopupElement) {
+  // Our caller isn't keeping us alive, so make sure we stay alive throughout
+  // this function in case one of the observer notifications destroys us.
+  RefPtr<NativeMenuMac> kungFuDeathGrip(this);
+
+  for (NativeMenu::Observer* observer : mObservers.Clone()) {
+    if (aPopupElement == mElement) {
+      observer->OnNativeMenuClosed();
+    } else {
+      observer->OnNativeSubMenuClosed(aPopupElement);
+    }
+  }
+}
+
+static NSView* NativeViewForFrame(nsIFrame* aFrame) {
+  nsIWidget* widget = aFrame->GetNearestWidget();
+  return (NSView*)widget->GetNativeData(NS_NATIVE_WIDGET);
+}
+
+static NSAppearance* NativeAppearanceForContent(nsIContent* aContent) {
+  nsIFrame* f = aContent->GetPrimaryFrame();
+  if (!f) {
+    return nil;
+  }
+  return NSAppearanceForColorScheme(LookAndFeel::ColorSchemeForFrame(f));
+}
+
+void NativeMenuMac::ShowAsContextMenu(nsIFrame* aClickedFrame,
+                                      const CSSIntPoint& aPosition,
+                                      bool aIsContextMenu) {
+  nsPresContext* pc = aClickedFrame->PresContext();
+  auto cssToDesktopScale =
+      pc->CSSToDevPixelScale() / pc->DeviceContext()->GetDesktopToDeviceScale();
+  const DesktopPoint desktopPoint = aPosition * cssToDesktopScale;
+
+  mMenu->PopupShowingEventWasSentAndApprovedExternally();
+
+  NSMenu* menu = mMenu->NativeNSMenu();
+  NSView* view = NativeViewForFrame(aClickedFrame);
+  NSAppearance* appearance = NativeAppearanceForContent(mMenu->Content());
+  NSPoint locationOnScreen = nsCocoaUtils::GeckoPointToCocoaPoint(desktopPoint);
+
+  // Let the MOZMenuOpeningCoordinator do the actual opening, so that this
+  // ShowAsContextMenu call does not spawn a nested event loop, which would be
+  // surprising to our callers.
+  mOpeningHandle = [MOZMenuOpeningCoordinator.sharedInstance
+      asynchronouslyOpenMenu:menu
+            atScreenPosition:locationOnScreen
+                     forView:view
+              withAppearance:appearance
+               asContextMenu:aIsContextMenu];
+}
+
+bool NativeMenuMac::Close() {
+  if (mOpeningHandle) {
+    // In case the menu was trying to open, but this Close() call interrupted
+    // it, cancel opening.
+    [MOZMenuOpeningCoordinator.sharedInstance
+        cancelAsynchronousOpening:mOpeningHandle];
+  }
+  return mMenu->Close();
+}
+
+RefPtr<nsMenuX> NativeMenuMac::GetOpenMenuContainingElement(
+    dom::Element* aElement) {
+  nsTArray<RefPtr<dom::Element>> submenuChain;
+  RefPtr<dom::Element> currentElement = aElement->GetParentElement();
+  while (currentElement && currentElement != mElement) {
+    if (currentElement->IsXULElement(nsGkAtoms::menu)) {
+      submenuChain.AppendElement(currentElement);
+    }
+    currentElement = currentElement->GetParentElement();
+  }
+  if (!currentElement) {
+    // aElement was not a descendent of mElement. Refuse to activate the item.
+    return nullptr;
+  }
+
+  // Traverse submenuChain from shallow to deep, to find the nsMenuX that
+  // contains aElement.
+  submenuChain.Reverse();
+  RefPtr<nsMenuX> menu = mMenu;
+  for (const auto& submenu : submenuChain) {
+    if (!menu->IsOpenForGecko()) {
+      // Refuse to descend into closed menus.
+      return nullptr;
+    }
+    Maybe<nsMenuX::MenuChild> menuChild = menu->GetItemForElement(submenu);
+    if (!menuChild || !menuChild->is<RefPtr<nsMenuX>>()) {
+      // Couldn't find submenu.
+      return nullptr;
+    }
+    menu = menuChild->as<RefPtr<nsMenuX>>();
+  }
+
+  if (!menu->IsOpenForGecko()) {
+    // Refuse to descend into closed menus.
+    return nullptr;
+  }
+  return menu;
+}
+
+static NSEventModifierFlags ConvertModifierFlags(Modifiers aModifiers) {
+  NSEventModifierFlags flags = 0;
+  if (aModifiers & MODIFIER_CONTROL) {
+    flags |= NSEventModifierFlagControl;
+  }
+  if (aModifiers & MODIFIER_ALT) {
+    flags |= NSEventModifierFlagOption;
+  }
+  if (aModifiers & MODIFIER_SHIFT) {
+    flags |= NSEventModifierFlagShift;
+  }
+  if (aModifiers & MODIFIER_META) {
+    flags |= NSEventModifierFlagCommand;
+  }
+  return flags;
+}
+
+void NativeMenuMac::ActivateItem(dom::Element* aItemElement,
+                                 Modifiers aModifiers, int16_t aButton,
+                                 ErrorResult& aRv) {
+  RefPtr<nsMenuX> menu = GetOpenMenuContainingElement(aItemElement);
+  if (!menu) {
+    aRv.ThrowInvalidStateError("Menu containing menu item is not open");
+    return;
+  }
+  Maybe<nsMenuX::MenuChild> child = menu->GetItemForElement(aItemElement);
+  if (!child || !child->is<RefPtr<nsMenuItemX>>()) {
+    aRv.ThrowInvalidStateError("Could not find the supplied menu item");
+    return;
+  }
+
+  RefPtr<nsMenuItemX> item = std::move(child->as<RefPtr<nsMenuItemX>>());
+  if (!item->IsVisible()) {
+    aRv.ThrowInvalidStateError("Menu item is not visible");
+    return;
+  }
+
+  NSMenuItem* nativeItem = [item->NativeNSMenuItem() retain];
+
+  // First, initiate the closing of the NSMenu.
+  // This synchronously calls the menu delegate's menuDidClose handler. So
+  // menuDidClose is what runs first; this matches the order of events for
+  // user-initiated menu item activation. This call doesn't immediately hide the
+  // menu; the menu only hides once the stack unwinds from NSMenu's nested
+  // "tracking" event loop.
+  [mMenu->NativeNSMenu() cancelTrackingWithoutAnimation];
+
+  // Next, call OnWillActivateItem. This also matches the order of calls that
+  // happen when a user activates a menu item in the real world: -[MenuDelegate
+  // menu:willActivateItem:] runs after menuDidClose.
+  menu->OnWillActivateItem(nativeItem);
+
+  // Finally, call ActivateItemAfterClosing. This also mimics the order in the
+  // real world: menuItemHit is called after menu:willActivateItem:.
+  menu->ActivateItemAfterClosing(std::move(item),
+                                 ConvertModifierFlags(aModifiers), aButton);
+
+  // Tell our native event loop that it should not process any more work before
+  // unwinding the stack, so that we can get out of the menu's nested event loop
+  // as fast as possible. This was needed to fix spurious failures in tests,
+  // where a call to cancelTrackingWithoutAnimation was ignored if more native
+  // events were processed before the event loop was exited. As a result, the
+  // menu stayed open forever and the test never finished.
+  MOZMenuOpeningCoordinator.needToUnwindForMenuClosing = YES;
+
+  [nativeItem release];
+}
+
+void NativeMenuMac::OpenSubmenu(dom::Element* aMenuElement) {
+  if (RefPtr<nsMenuX> menu = GetOpenMenuContainingElement(aMenuElement)) {
+    Maybe<nsMenuX::MenuChild> item = menu->GetItemForElement(aMenuElement);
+    if (item && item->is<RefPtr<nsMenuX>>()) {
+      item->as<RefPtr<nsMenuX>>()->MenuOpened();
+    }
+  }
+}
+
+void NativeMenuMac::CloseSubmenu(dom::Element* aMenuElement) {
+  if (RefPtr<nsMenuX> menu = GetOpenMenuContainingElement(aMenuElement)) {
+    Maybe<nsMenuX::MenuChild> item = menu->GetItemForElement(aMenuElement);
+    if (item && item->is<RefPtr<nsMenuX>>()) {
+      item->as<RefPtr<nsMenuX>>()->MenuClosed();
+    }
+  }
+}
+
+RefPtr<Element> NativeMenuMac::Element() { return mElement; }
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/cocoa/NativeMenuSupport.mm b/widget/cocoa/NativeMenuSupport.mm
new file mode 100644
index 0000000000..2e94f6f7cf
--- /dev/null
+++ b/widget/cocoa/NativeMenuSupport.mm
@@ -0,0 +1,37 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/widget/NativeMenuSupport.h"
+
+#include "MainThreadUtils.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "NativeMenuMac.h"
+#include "nsCocoaWindow.h"
+#include "nsMenuBarX.h"
+
+namespace mozilla::widget {
+
+void NativeMenuSupport::CreateNativeMenuBar(nsIWidget* aParent,
+                                            dom::Element* aMenuBarElement) {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread(),
+                     "Attempting to create native menu bar on wrong thread!");
+
+  // Create the menubar and give it to the parent window. The parent takes
+  // ownership.
+  static_cast<nsCocoaWindow*>(aParent)->SetMenuBar(
+      MakeRefPtr<nsMenuBarX>(aMenuBarElement));
+}
+
+already_AddRefed<NativeMenu> NativeMenuSupport::CreateNativeContextMenu(
+    dom::Element* aPopup) {
+  return MakeAndAddRef<NativeMenuMac>(aPopup);
+}
+
+bool NativeMenuSupport::ShouldUseNativeContextMenus() {
+  return StaticPrefs::widget_macos_native_context_menus();
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/cocoa/OSXNotificationCenter.h b/widget/cocoa/OSXNotificationCenter.h
new file mode 100644
index 0000000000..65025d04ab
--- /dev/null
+++ b/widget/cocoa/OSXNotificationCenter.h
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef OSXNotificationCenter_h
+#define OSXNotificationCenter_h
+
+#import <Foundation/Foundation.h>
+#include "nsIAlertsService.h"
+#include "nsTArray.h"
+#include "mozilla/RefPtr.h"
+
+// mozNotificationCenterDelegate is used to access the macOS notification
+// center. It is not related to the DesktopNotificationCenter object, which was
+// removed in bug 952453. While there are no direct references to this class
+// elsewhere, removing this will cause push notifications on macOS to stop
+// working.
+@class mozNotificationCenterDelegate;
+
+namespace mozilla {
+
+class OSXNotificationInfo;
+
+class OSXNotificationCenter : public nsIAlertsService,
+                              public nsIAlertsIconData,
+                              public nsIAlertsDoNotDisturb,
+                              public nsIAlertNotificationImageListener {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIALERTSSERVICE
+  NS_DECL_NSIALERTSICONDATA
+  NS_DECL_NSIALERTSDONOTDISTURB
+  NS_DECL_NSIALERTNOTIFICATIONIMAGELISTENER
+
+  OSXNotificationCenter();
+
+  nsresult Init();
+  void CloseAlertCocoaString(NSString* aAlertName);
+  void OnActivate(NSString* aAlertName,
+                  NSUserNotificationActivationType aActivationType,
+                  unsigned long long aAdditionalActionIndex);
+  void ShowPendingNotification(OSXNotificationInfo* osxni);
+
+ protected:
+  virtual ~OSXNotificationCenter();
+
+ private:
+  mozNotificationCenterDelegate* mDelegate;
+  nsTArray<RefPtr<OSXNotificationInfo> > mActiveAlerts;
+  nsTArray<RefPtr<OSXNotificationInfo> > mPendingAlerts;
+  bool mSuppressForScreenSharing;
+};
+
+}  // namespace mozilla
+
+#endif  // OSXNotificationCenter_h
diff --git a/widget/cocoa/OSXNotificationCenter.mm b/widget/cocoa/OSXNotificationCenter.mm
new file mode 100644
index 0000000000..07cb026f1f
--- /dev/null
+++ b/widget/cocoa/OSXNotificationCenter.mm
@@ -0,0 +1,591 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "OSXNotificationCenter.h"
+#import <AppKit/AppKit.h>
+#include "imgIRequest.h"
+#include "imgIContainer.h"
+#include "nsICancelable.h"
+#include "nsIStringBundle.h"
+#include "nsNetUtil.h"
+#import "nsCocoaUtils.h"
+#include "nsComponentManagerUtils.h"
+#include "nsContentUtils.h"
+#include "nsObjCExceptions.h"
+#include "nsString.h"
+#include "nsCOMPtr.h"
+#include "nsIObserver.h"
+
+using namespace mozilla;
+
+#define MAX_NOTIFICATION_NAME_LEN 5000
+
+@protocol FakeNSUserNotification <NSObject>
+@property(copy) NSString* title;
+@property(copy) NSString* subtitle;
+@property(copy) NSString* informativeText;
+@property(copy) NSString* actionButtonTitle;
+@property(copy) NSDictionary* userInfo;
+@property(copy) NSDate* deliveryDate;
+@property(copy) NSTimeZone* deliveryTimeZone;
+@property(copy) NSDateComponents* deliveryRepeatInterval;
+@property(readonly) NSDate* actualDeliveryDate;
+@property(readonly, getter=isPresented) BOOL presented;
+@property(readonly, getter=isRemote) BOOL remote;
+@property(copy) NSString* soundName;
+@property BOOL hasActionButton;
+@property(readonly) NSUserNotificationActivationType activationType;
+@property(copy) NSString* otherButtonTitle;
+@property(copy) NSImage* contentImage;
+@end
+
+@protocol FakeNSUserNotificationCenter <NSObject>
++ (id<FakeNSUserNotificationCenter>)defaultUserNotificationCenter;
+@property(assign) id<NSUserNotificationCenterDelegate> delegate;
+@property(copy) NSArray* scheduledNotifications;
+- (void)scheduleNotification:(id<FakeNSUserNotification>)notification;
+- (void)removeScheduledNotification:(id<FakeNSUserNotification>)notification;
+@property(readonly) NSArray* deliveredNotifications;
+- (void)deliverNotification:(id<FakeNSUserNotification>)notification;
+- (void)removeDeliveredNotification:(id<FakeNSUserNotification>)notification;
+- (void)removeAllDeliveredNotifications;
+- (void)_removeAllDisplayedNotifications;
+- (void)_removeDisplayedNotification:(id<FakeNSUserNotification>)notification;
+@end
+
+@interface mozNotificationCenterDelegate
+    : NSObject <NSUserNotificationCenterDelegate> {
+  OSXNotificationCenter* mOSXNC;
+}
+- (id)initWithOSXNC:(OSXNotificationCenter*)osxnc;
+@end
+
+@implementation mozNotificationCenterDelegate
+
+- (id)initWithOSXNC:(OSXNotificationCenter*)osxnc {
+  [super init];
+  // We should *never* outlive this OSXNotificationCenter.
+  mOSXNC = osxnc;
+  return self;
+}
+
+- (void)userNotificationCenter:(id<FakeNSUserNotificationCenter>)center
+        didDeliverNotification:(id<FakeNSUserNotification>)notification {
+}
+
+- (void)userNotificationCenter:(id<FakeNSUserNotificationCenter>)center
+       didActivateNotification:(id<FakeNSUserNotification>)notification {
+  unsigned long long additionalActionIndex = ULLONG_MAX;
+  if ([notification respondsToSelector:@selector(_alternateActionIndex)]) {
+    NSNumber* alternateActionIndex =
+        [(NSObject*)notification valueForKey:@"_alternateActionIndex"];
+    additionalActionIndex = [alternateActionIndex unsignedLongLongValue];
+  }
+  mOSXNC->OnActivate([[notification userInfo] valueForKey:@"name"],
+                     notification.activationType, additionalActionIndex);
+}
+
+- (BOOL)userNotificationCenter:(id<FakeNSUserNotificationCenter>)center
+     shouldPresentNotification:(id<FakeNSUserNotification>)notification {
+  return YES;
+}
+
+// This is an undocumented method that we need for parity with Safari.
+// Apple bug #15440664.
+- (void)userNotificationCenter:(id<FakeNSUserNotificationCenter>)center
+    didRemoveDeliveredNotifications:(NSArray*)notifications {
+  for (id<FakeNSUserNotification> notification in notifications) {
+    NSString* name = [[notification userInfo] valueForKey:@"name"];
+    mOSXNC->CloseAlertCocoaString(name);
+  }
+}
+
+// This is an undocumented method that we need to be notified if a user clicks
+// the close button.
+- (void)userNotificationCenter:(id<FakeNSUserNotificationCenter>)center
+               didDismissAlert:(id<FakeNSUserNotification>)notification {
+  NSString* name = [[notification userInfo] valueForKey:@"name"];
+  mOSXNC->CloseAlertCocoaString(name);
+}
+
+@end
+
+namespace mozilla {
+
+enum {
+  OSXNotificationActionDisable = 0,
+  OSXNotificationActionSettings = 1,
+};
+
+class OSXNotificationInfo final : public nsISupports {
+ private:
+  virtual ~OSXNotificationInfo();
+
+ public:
+  NS_DECL_ISUPPORTS
+  OSXNotificationInfo(NSString* name, nsIObserver* observer,
+                      const nsAString& alertCookie);
+
+  NSString* mName;
+  nsCOMPtr<nsIObserver> mObserver;
+  nsString mCookie;
+  RefPtr<nsICancelable> mIconRequest;
+  id<FakeNSUserNotification> mPendingNotification;
+};
+
+NS_IMPL_ISUPPORTS0(OSXNotificationInfo)
+
+OSXNotificationInfo::OSXNotificationInfo(NSString* name, nsIObserver* observer,
+                                         const nsAString& alertCookie) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NS_ASSERTION(name, "Cannot create OSXNotificationInfo without a name!");
+  mName = [name retain];
+  mObserver = observer;
+  mCookie = alertCookie;
+  mPendingNotification = nil;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+OSXNotificationInfo::~OSXNotificationInfo() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [mName release];
+  [mPendingNotification release];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+static id<FakeNSUserNotificationCenter> GetNotificationCenter() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  Class c = NSClassFromString(@"NSUserNotificationCenter");
+  return [c performSelector:@selector(defaultUserNotificationCenter)];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+OSXNotificationCenter::OSXNotificationCenter() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  mDelegate = [[mozNotificationCenterDelegate alloc] initWithOSXNC:this];
+  GetNotificationCenter().delegate = mDelegate;
+  mSuppressForScreenSharing = false;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+OSXNotificationCenter::~OSXNotificationCenter() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [GetNotificationCenter() removeAllDeliveredNotifications];
+  [mDelegate release];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+NS_IMPL_ISUPPORTS(OSXNotificationCenter, nsIAlertsService, nsIAlertsIconData,
+                  nsIAlertsDoNotDisturb, nsIAlertNotificationImageListener)
+
+nsresult OSXNotificationCenter::Init() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return (!!NSClassFromString(@"NSUserNotification")) ? NS_OK
+                                                      : NS_ERROR_FAILURE;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+OSXNotificationCenter::ShowAlertNotification(
+    const nsAString& aImageUrl, const nsAString& aAlertTitle,
+    const nsAString& aAlertText, bool aAlertTextClickable,
+    const nsAString& aAlertCookie, nsIObserver* aAlertListener,
+    const nsAString& aAlertName, const nsAString& aBidi, const nsAString& aLang,
+    const nsAString& aData, nsIPrincipal* aPrincipal, bool aInPrivateBrowsing,
+    bool aRequireInteraction) {
+  nsCOMPtr<nsIAlertNotification> alert =
+      do_CreateInstance(ALERT_NOTIFICATION_CONTRACTID);
+  NS_ENSURE_TRUE(alert, NS_ERROR_FAILURE);
+  // vibrate is unused for now
+  nsTArray<uint32_t> vibrate;
+  nsresult rv = alert->Init(aAlertName, aImageUrl, aAlertTitle, aAlertText,
+                            aAlertTextClickable, aAlertCookie, aBidi, aLang,
+                            aData, aPrincipal, aInPrivateBrowsing,
+                            aRequireInteraction, false, vibrate);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return ShowAlert(alert, aAlertListener);
+}
+
+NS_IMETHODIMP
+OSXNotificationCenter::ShowPersistentNotification(
+    const nsAString& aPersistentData, nsIAlertNotification* aAlert,
+    nsIObserver* aAlertListener) {
+  return ShowAlert(aAlert, aAlertListener);
+}
+
+NS_IMETHODIMP
+OSXNotificationCenter::ShowAlert(nsIAlertNotification* aAlert,
+                                 nsIObserver* aAlertListener) {
+  return ShowAlertWithIconData(aAlert, aAlertListener, 0, nullptr);
+}
+
+NS_IMETHODIMP
+OSXNotificationCenter::ShowAlertWithIconData(nsIAlertNotification* aAlert,
+                                             nsIObserver* aAlertListener,
+                                             uint32_t aIconSize,
+                                             const uint8_t* aIconData) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NS_ENSURE_ARG(aAlert);
+
+  if (mSuppressForScreenSharing) {
+    return NS_OK;
+  }
+
+  Class unClass = NSClassFromString(@"NSUserNotification");
+  id<FakeNSUserNotification> notification = [[unClass alloc] init];
+
+  nsAutoString title;
+  nsresult rv = aAlert->GetTitle(title);
+  NS_ENSURE_SUCCESS(rv, rv);
+  notification.title = nsCocoaUtils::ToNSString(title);
+
+  nsAutoString hostPort;
+  rv = aAlert->GetSource(hostPort);
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIStringBundle> bundle;
+  nsCOMPtr<nsIStringBundleService> sbs =
+      do_GetService(NS_STRINGBUNDLE_CONTRACTID);
+  sbs->CreateBundle("chrome://alerts/locale/alert.properties",
+                    getter_AddRefs(bundle));
+
+  if (!hostPort.IsEmpty() && bundle) {
+    AutoTArray<nsString, 1> formatStrings = {hostPort};
+    nsAutoString notificationSource;
+    bundle->FormatStringFromName("source.label", formatStrings,
+                                 notificationSource);
+    notification.subtitle = nsCocoaUtils::ToNSString(notificationSource);
+  }
+
+  nsAutoString text;
+  rv = aAlert->GetText(text);
+  NS_ENSURE_SUCCESS(rv, rv);
+  notification.informativeText = nsCocoaUtils::ToNSString(text);
+
+  bool isSilent;
+  aAlert->GetSilent(&isSilent);
+  notification.soundName = isSilent ? nil : NSUserNotificationDefaultSoundName;
+  notification.hasActionButton = NO;
+
+  // If this is not an application/extension alert, show additional actions
+  // dealing with permissions.
+  bool isActionable;
+  if (bundle && NS_SUCCEEDED(aAlert->GetActionable(&isActionable)) &&
+      isActionable) {
+    nsAutoString closeButtonTitle, actionButtonTitle, disableButtonTitle,
+        settingsButtonTitle;
+    bundle->GetStringFromName("closeButton.title", closeButtonTitle);
+    bundle->GetStringFromName("actionButton.label", actionButtonTitle);
+    if (!hostPort.IsEmpty()) {
+      AutoTArray<nsString, 1> formatStrings = {hostPort};
+      bundle->FormatStringFromName("webActions.disableForOrigin.label",
+                                   formatStrings, disableButtonTitle);
+    }
+    bundle->GetStringFromName("webActions.settings.label", settingsButtonTitle);
+
+    notification.otherButtonTitle = nsCocoaUtils::ToNSString(closeButtonTitle);
+
+    // OS X 10.8 only shows action buttons if the "Alerts" style is set in
+    // Notification Center preferences, and doesn't support the alternate
+    // action menu.
+    if ([notification respondsToSelector:@selector(set_showsButtons:)] &&
+        [notification
+            respondsToSelector:@selector(set_alwaysShowAlternateActionMenu:)] &&
+        [notification
+            respondsToSelector:@selector(set_alternateActionButtonTitles:)]) {
+      notification.hasActionButton = YES;
+      notification.actionButtonTitle =
+          nsCocoaUtils::ToNSString(actionButtonTitle);
+
+      [(NSObject*)notification setValue:@(YES) forKey:@"_showsButtons"];
+      [(NSObject*)notification setValue:@(YES)
+                                 forKey:@"_alwaysShowAlternateActionMenu"];
+      [(NSObject*)notification setValue:@[
+        nsCocoaUtils::ToNSString(disableButtonTitle),
+        nsCocoaUtils::ToNSString(settingsButtonTitle)
+      ]
+                                 forKey:@"_alternateActionButtonTitles"];
+    }
+  }
+  nsAutoString name;
+  rv = aAlert->GetName(name);
+  // Don't let an alert name be more than MAX_NOTIFICATION_NAME_LEN characters.
+  // More than that shouldn't be necessary and userInfo (assigned to below) has
+  // a length limit of 16k on OS X 10.11. Exception thrown if limit exceeded.
+  if (name.Length() > MAX_NOTIFICATION_NAME_LEN) {
+    return NS_ERROR_FAILURE;
+  }
+
+  NS_ENSURE_SUCCESS(rv, rv);
+  NSString* alertName = nsCocoaUtils::ToNSString(name);
+  if (!alertName) {
+    return NS_ERROR_FAILURE;
+  }
+  notification.userInfo = [NSDictionary
+      dictionaryWithObjects:[NSArray arrayWithObjects:alertName, nil]
+                    forKeys:[NSArray arrayWithObjects:@"name", nil]];
+
+  nsAutoString cookie;
+  rv = aAlert->GetCookie(cookie);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  OSXNotificationInfo* osxni =
+      new OSXNotificationInfo(alertName, aAlertListener, cookie);
+
+  // Show the favicon if supported on this version of OS X.
+  if (aIconSize > 0 &&
+      [notification respondsToSelector:@selector(set_identityImage:)] &&
+      [notification
+          respondsToSelector:@selector(set_identityImageHasBorder:)]) {
+    NSData* iconData = [NSData dataWithBytes:aIconData length:aIconSize];
+    NSImage* icon = [[[NSImage alloc] initWithData:iconData] autorelease];
+
+    [(NSObject*)notification setValue:icon forKey:@"_identityImage"];
+    [(NSObject*)notification setValue:@(NO) forKey:@"_identityImageHasBorder"];
+  }
+
+  bool inPrivateBrowsing;
+  rv = aAlert->GetInPrivateBrowsing(&inPrivateBrowsing);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Show the notification without waiting for an image if there is no icon URL
+  // or notification icons are not supported on this version of OS X.
+  if (![unClass instancesRespondToSelector:@selector(setContentImage:)]) {
+    CloseAlertCocoaString(alertName);
+    mActiveAlerts.AppendElement(osxni);
+    [GetNotificationCenter() deliverNotification:notification];
+    [notification release];
+    if (aAlertListener) {
+      aAlertListener->Observe(nullptr, "alertshow", cookie.get());
+    }
+  } else {
+    mPendingAlerts.AppendElement(osxni);
+    osxni->mPendingNotification = notification;
+    // Wait six seconds for the image to load.
+    rv = aAlert->LoadImage(6000, this, osxni,
+                           getter_AddRefs(osxni->mIconRequest));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      ShowPendingNotification(osxni);
+    }
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+OSXNotificationCenter::CloseAlert(const nsAString& aAlertName,
+                                  bool aContextClosed) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSString* alertName = nsCocoaUtils::ToNSString(aAlertName);
+  CloseAlertCocoaString(alertName);
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void OSXNotificationCenter::CloseAlertCocoaString(NSString* aAlertName) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!aAlertName) {
+    return;  // Can't do anything without a name
+  }
+
+  NSArray* notifications = [GetNotificationCenter() deliveredNotifications];
+  for (id<FakeNSUserNotification> notification in notifications) {
+    NSString* name = [[notification userInfo] valueForKey:@"name"];
+    if ([name isEqualToString:aAlertName]) {
+      [GetNotificationCenter() removeDeliveredNotification:notification];
+      [GetNotificationCenter() _removeDisplayedNotification:notification];
+      break;
+    }
+  }
+
+  for (unsigned int i = 0; i < mActiveAlerts.Length(); i++) {
+    OSXNotificationInfo* osxni = mActiveAlerts[i];
+    if ([aAlertName isEqualToString:osxni->mName]) {
+      if (osxni->mObserver) {
+        osxni->mObserver->Observe(nullptr, "alertfinished",
+                                  osxni->mCookie.get());
+      }
+      if (osxni->mIconRequest) {
+        osxni->mIconRequest->Cancel(NS_BINDING_ABORTED);
+        osxni->mIconRequest = nullptr;
+      }
+      mActiveAlerts.RemoveElementAt(i);
+      break;
+    }
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void OSXNotificationCenter::OnActivate(
+    NSString* aAlertName, NSUserNotificationActivationType aActivationType,
+    unsigned long long aAdditionalActionIndex) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!aAlertName) {
+    return;  // Can't do anything without a name
+  }
+
+  for (unsigned int i = 0; i < mActiveAlerts.Length(); i++) {
+    OSXNotificationInfo* osxni = mActiveAlerts[i];
+    if ([aAlertName isEqualToString:osxni->mName]) {
+      if (osxni->mObserver) {
+        switch ((int)aActivationType) {
+          case NSUserNotificationActivationTypeAdditionalActionClicked:
+          case NSUserNotificationActivationTypeActionButtonClicked:
+            switch (aAdditionalActionIndex) {
+              case OSXNotificationActionDisable:
+                osxni->mObserver->Observe(nullptr, "alertdisablecallback",
+                                          osxni->mCookie.get());
+                break;
+              case OSXNotificationActionSettings:
+                osxni->mObserver->Observe(nullptr, "alertsettingscallback",
+                                          osxni->mCookie.get());
+                break;
+              default:
+                NS_WARNING(
+                    "Unknown NSUserNotification additional action clicked");
+                break;
+            }
+            break;
+          default:
+            osxni->mObserver->Observe(nullptr, "alertclickcallback",
+                                      osxni->mCookie.get());
+            break;
+        }
+      }
+      return;
+    }
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void OSXNotificationCenter::ShowPendingNotification(
+    OSXNotificationInfo* osxni) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (osxni->mIconRequest) {
+    osxni->mIconRequest->Cancel(NS_BINDING_ABORTED);
+    osxni->mIconRequest = nullptr;
+  }
+
+  CloseAlertCocoaString(osxni->mName);
+
+  for (unsigned int i = 0; i < mPendingAlerts.Length(); i++) {
+    if (mPendingAlerts[i] == osxni) {
+      mActiveAlerts.AppendElement(osxni);
+      mPendingAlerts.RemoveElementAt(i);
+      break;
+    }
+  }
+
+  [GetNotificationCenter() deliverNotification:osxni->mPendingNotification];
+
+  if (osxni->mObserver) {
+    osxni->mObserver->Observe(nullptr, "alertshow", osxni->mCookie.get());
+  }
+
+  [osxni->mPendingNotification release];
+  osxni->mPendingNotification = nil;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+NS_IMETHODIMP
+OSXNotificationCenter::OnImageMissing(nsISupports* aUserData) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  OSXNotificationInfo* osxni = static_cast<OSXNotificationInfo*>(aUserData);
+  if (osxni->mPendingNotification) {
+    // If there was an error getting the image, or the request timed out, show
+    // the notification without a content image.
+    ShowPendingNotification(osxni);
+  }
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+OSXNotificationCenter::OnImageReady(nsISupports* aUserData,
+                                    imgIRequest* aRequest) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  nsCOMPtr<imgIContainer> image;
+  nsresult rv = aRequest->GetImage(getter_AddRefs(image));
+  if (NS_WARN_IF(NS_FAILED(rv) || !image)) {
+    return rv;
+  }
+
+  OSXNotificationInfo* osxni = static_cast<OSXNotificationInfo*>(aUserData);
+  if (!osxni->mPendingNotification) {
+    return NS_ERROR_FAILURE;
+  }
+
+  NSImage* cocoaImage = nil;
+  // TODO: Pass pres context / ComputedStyle here to support context paint
+  // properties
+  nsCocoaUtils::CreateDualRepresentationNSImageFromImageContainer(
+      image, imgIContainer::FRAME_FIRST, nullptr, nullptr, &cocoaImage);
+  (osxni->mPendingNotification).contentImage = cocoaImage;
+  [cocoaImage release];
+  ShowPendingNotification(osxni);
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+// nsIAlertsDoNotDisturb
+NS_IMETHODIMP
+OSXNotificationCenter::GetManualDoNotDisturb(bool* aRetVal) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+OSXNotificationCenter::SetManualDoNotDisturb(bool aDoNotDisturb) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+OSXNotificationCenter::GetSuppressForScreenSharing(bool* aRetVal) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+
+  NS_ENSURE_ARG(aRetVal);
+  *aRetVal = mSuppressForScreenSharing;
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE)
+}
+
+NS_IMETHODIMP
+OSXNotificationCenter::SetSuppressForScreenSharing(bool aSuppress) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+
+  mSuppressForScreenSharing = aSuppress;
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE)
+}
+
+}  // namespace mozilla
diff --git a/widget/cocoa/ScreenHelperCocoa.h b/widget/cocoa/ScreenHelperCocoa.h
new file mode 100644
index 0000000000..91f4a19677
--- /dev/null
+++ b/widget/cocoa/ScreenHelperCocoa.h
@@ -0,0 +1,34 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_cocoa_ScreenHelperCocoa_h
+#define mozilla_widget_cocoa_ScreenHelperCocoa_h
+
+#include "mozilla/widget/ScreenManager.h"
+
+@class ScreenHelperDelegate;
+@class NSScreen;
+
+namespace mozilla {
+namespace widget {
+
+class ScreenHelperCocoa final : public ScreenManager::Helper {
+ public:
+  ScreenHelperCocoa();
+  ~ScreenHelperCocoa() override;
+
+  void RefreshScreens();
+
+  static NSScreen* CocoaScreenForScreen(nsIScreen* aScreen);
+
+ private:
+  ScreenHelperDelegate* mDelegate;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_gtk_ScreenHelperGtk_h
diff --git a/widget/cocoa/ScreenHelperCocoa.mm b/widget/cocoa/ScreenHelperCocoa.mm
new file mode 100644
index 0000000000..57e1313320
--- /dev/null
+++ b/widget/cocoa/ScreenHelperCocoa.mm
@@ -0,0 +1,181 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScreenHelperCocoa.h"
+
+#import <Cocoa/Cocoa.h>
+
+#include "mozilla/Logging.h"
+#include "nsCocoaUtils.h"
+#include "nsObjCExceptions.h"
+
+using namespace mozilla;
+
+static LazyLogModule sScreenLog("WidgetScreen");
+
+@interface ScreenHelperDelegate : NSObject {
+ @private
+  mozilla::widget::ScreenHelperCocoa* mHelper;
+}
+
+- (id)initWithScreenHelper:(mozilla::widget::ScreenHelperCocoa*)aScreenHelper;
+- (void)didChangeScreenParameters:(NSNotification*)aNotification;
+@end
+
+@implementation ScreenHelperDelegate
+- (id)initWithScreenHelper:(mozilla::widget::ScreenHelperCocoa*)aScreenHelper {
+  if ((self = [self init])) {
+    mHelper = aScreenHelper;
+
+    [[NSNotificationCenter defaultCenter]
+        addObserver:self
+           selector:@selector(didChangeScreenParameters:)
+               name:NSApplicationDidChangeScreenParametersNotification
+             object:nil];
+  }
+
+  return self;
+}
+
+- (void)dealloc {
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+  [super dealloc];
+}
+
+- (void)didChangeScreenParameters:(NSNotification*)aNotification {
+  MOZ_LOG(sScreenLog, LogLevel::Debug,
+          ("Received NSApplicationDidChangeScreenParametersNotification"));
+
+  mHelper->RefreshScreens();
+}
+@end
+
+namespace mozilla {
+namespace widget {
+
+ScreenHelperCocoa::ScreenHelperCocoa() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_LOG(sScreenLog, LogLevel::Debug, ("ScreenHelperCocoa created"));
+
+  mDelegate = [[ScreenHelperDelegate alloc] initWithScreenHelper:this];
+
+  RefreshScreens();
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+ScreenHelperCocoa::~ScreenHelperCocoa() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [mDelegate release];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+static already_AddRefed<Screen> MakeScreen(NSScreen* aScreen) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  DesktopToLayoutDeviceScale contentsScaleFactor(
+      nsCocoaUtils::GetBackingScaleFactor(aScreen));
+  CSSToLayoutDeviceScale defaultCssScaleFactor(contentsScaleFactor.scale);
+  NSRect frame = [aScreen frame];
+  LayoutDeviceIntRect rect = nsCocoaUtils::CocoaRectToGeckoRectDevPix(
+      frame, contentsScaleFactor.scale);
+  frame = [aScreen visibleFrame];
+  LayoutDeviceIntRect availRect = nsCocoaUtils::CocoaRectToGeckoRectDevPix(
+      frame, contentsScaleFactor.scale);
+
+  // aScreen may be capable of displaying multiple pixel depths, for example by
+  // transitioning to an HDR-capable depth when required by a window displayed
+  // on the screen. We want to note the maximum capabilities of the screen, so
+  // we use the largest depth it offers.
+  uint32_t pixelDepth = 0;
+  const NSWindowDepth* depths = [aScreen supportedWindowDepths];
+  for (size_t d = 0; NSWindowDepth depth = depths[d]; d++) {
+    uint32_t bpp = NSBitsPerPixelFromDepth(depth);
+    if (bpp > pixelDepth) {
+      pixelDepth = bpp;
+    }
+  }
+
+  // But it confuses content if we return too-high a value here. Cap depth with
+  // a value that matches what Chrome returns for high bpp screens.
+  static const uint32_t MAX_REPORTED_PIXEL_DEPTH = 30;
+  if (pixelDepth > MAX_REPORTED_PIXEL_DEPTH) {
+    pixelDepth = MAX_REPORTED_PIXEL_DEPTH;
+  }
+
+  float dpi = 96.0f;
+  CGDirectDisplayID displayID =
+      [[[aScreen deviceDescription] objectForKey:@"NSScreenNumber"] intValue];
+  CGFloat heightMM = ::CGDisplayScreenSize(displayID).height;
+  if (heightMM > 0) {
+    dpi = rect.height / (heightMM / MM_PER_INCH_FLOAT);
+  }
+  MOZ_LOG(sScreenLog, LogLevel::Debug,
+          ("New screen [%d %d %d %d (%d %d %d %d) %d %f %f %f]", rect.x, rect.y,
+           rect.width, rect.height, availRect.x, availRect.y, availRect.width,
+           availRect.height, pixelDepth, contentsScaleFactor.scale,
+           defaultCssScaleFactor.scale, dpi));
+
+  // Getting the refresh rate is a little hard on OS X. We could use
+  // CVDisplayLinkGetNominalOutputVideoRefreshPeriod, but that's a little
+  // involved. Ideally we could query it from vsync. For now, we leave it out.
+  RefPtr<Screen> screen = new Screen(rect, availRect, pixelDepth, pixelDepth, 0,
+                                     contentsScaleFactor, defaultCssScaleFactor,
+                                     dpi, Screen::IsPseudoDisplay::No);
+  return screen.forget();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nullptr);
+}
+
+void ScreenHelperCocoa::RefreshScreens() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_LOG(sScreenLog, LogLevel::Debug, ("Refreshing screens"));
+
+  AutoTArray<RefPtr<Screen>, 4> screens;
+
+  for (NSScreen* screen in [NSScreen screens]) {
+    NSDictionary* desc = [screen deviceDescription];
+    if ([desc objectForKey:NSDeviceIsScreen] == nil) {
+      continue;
+    }
+    screens.AppendElement(MakeScreen(screen));
+  }
+
+  ScreenManager::Refresh(std::move(screens));
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+NSScreen* ScreenHelperCocoa::CocoaScreenForScreen(nsIScreen* aScreen) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  for (NSScreen* screen in [NSScreen screens]) {
+    NSDictionary* desc = [screen deviceDescription];
+    if ([desc objectForKey:NSDeviceIsScreen] == nil) {
+      continue;
+    }
+    LayoutDeviceIntRect rect;
+    double scale;
+    aScreen->GetRect(&rect.x, &rect.y, &rect.width, &rect.height);
+    aScreen->GetContentsScaleFactor(&scale);
+    NSRect frame = [screen frame];
+    LayoutDeviceIntRect frameRect =
+        nsCocoaUtils::CocoaRectToGeckoRectDevPix(frame, scale);
+    if (rect == frameRect) {
+      return screen;
+    }
+  }
+  return [NSScreen mainScreen];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/cocoa/TextInputHandler.h b/widget/cocoa/TextInputHandler.h
new file mode 100644
index 0000000000..d55a7c32b9
--- /dev/null
+++ b/widget/cocoa/TextInputHandler.h
@@ -0,0 +1,1352 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 sw=2 et tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef TextInputHandler_h_
+#define TextInputHandler_h_
+
+#include "nsCocoaUtils.h"
+
+#import <Carbon/Carbon.h>
+#import <Cocoa/Cocoa.h>
+#include "mozView.h"
+#include "nsString.h"
+#include "nsCOMPtr.h"
+#include "nsITimer.h"
+#include "nsTArray.h"
+#include "mozilla/BasicEvents.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/TextEventDispatcherListener.h"
+#include "WritingModes.h"
+
+class nsChildView;
+
+namespace mozilla {
+namespace widget {
+
+// Key code constants
+enum {
+  kVK_PC_PrintScreen = kVK_F13,
+  kVK_PC_ScrollLock = kVK_F14,
+  kVK_PC_Pause = kVK_F15,
+
+  kVK_PC_Insert = kVK_Help,
+  kVK_PC_Backspace = kVK_Delete,
+  kVK_PC_Delete = kVK_ForwardDelete,
+
+  kVK_PC_ContextMenu = 0x6E,
+
+  kVK_Powerbook_KeypadEnter =
+      0x34  // Enter on Powerbook's keyboard is different
+};
+
+/**
+ * TISInputSourceWrapper is a wrapper for the TISInputSourceRef.  If we get the
+ * TISInputSourceRef from InputSourceID, we need to release the CFArray instance
+ * which is returned by TISCreateInputSourceList.  However, when we release the
+ * list, we cannot access the TISInputSourceRef.  So, it's not usable, and it
+ * may cause the memory leak bugs.  nsTISInputSource automatically releases the
+ * list when the instance is destroyed.
+ */
+class TISInputSourceWrapper {
+ public:
+  static TISInputSourceWrapper& CurrentInputSource();
+  /**
+   * Shutdown() should be called when nobody doesn't need to use this class.
+   */
+  static void Shutdown();
+
+  TISInputSourceWrapper()
+      : mInputSource{nullptr},
+        mKeyboardLayout{nullptr},
+        mUCKeyboardLayout{nullptr},
+        mIsRTL{0},
+        mOverrideKeyboard{false} {
+    mInputSourceList = nullptr;
+    Clear();
+  }
+
+  explicit TISInputSourceWrapper(const char* aID)
+      : mInputSource{nullptr},
+        mKeyboardLayout{nullptr},
+        mUCKeyboardLayout{nullptr},
+        mIsRTL{0},
+        mOverrideKeyboard{false} {
+    mInputSourceList = nullptr;
+    InitByInputSourceID(aID);
+  }
+
+  explicit TISInputSourceWrapper(SInt32 aLayoutID)
+      : mInputSource{nullptr},
+        mKeyboardLayout{nullptr},
+        mUCKeyboardLayout{nullptr},
+        mIsRTL{0},
+        mOverrideKeyboard{false} {
+    mInputSourceList = nullptr;
+    InitByLayoutID(aLayoutID);
+  }
+
+  explicit TISInputSourceWrapper(TISInputSourceRef aInputSource)
+      : mInputSource{nullptr},
+        mKeyboardLayout{nullptr},
+        mUCKeyboardLayout{nullptr},
+        mIsRTL{0},
+        mOverrideKeyboard{false} {
+    mInputSourceList = nullptr;
+    InitByTISInputSourceRef(aInputSource);
+  }
+
+  ~TISInputSourceWrapper() { Clear(); }
+
+  void InitByInputSourceID(const char* aID);
+  void InitByInputSourceID(const nsString& aID);
+  void InitByInputSourceID(const CFStringRef aID);
+  /**
+   * InitByLayoutID() initializes the keyboard layout by the layout ID.
+   *
+   * @param aLayoutID             An ID of keyboard layout.
+   *                                0: US
+   *                                1: Greek
+   *                                2: German
+   *                                3: Swedish-Pro
+   *                                4: Dvorak-Qwerty Cmd
+   *                                5: Thai
+   *                                6: Arabic
+   *                                7: French
+   *                                8: Hebrew
+   *                                9: Lithuanian
+   *                               10: Norwegian
+   *                               11: Spanish
+   * @param aOverrideKeyboard     When testing set to TRUE, otherwise, set to
+   *                              FALSE.  When TRUE, we use an ANSI keyboard
+   *                              instead of the actual keyboard.
+   */
+  void InitByLayoutID(SInt32 aLayoutID, bool aOverrideKeyboard = false);
+  void InitByCurrentInputSource();
+  void InitByCurrentKeyboardLayout();
+  void InitByCurrentASCIICapableInputSource();
+  void InitByCurrentASCIICapableKeyboardLayout();
+  void InitByCurrentInputMethodKeyboardLayoutOverride();
+  void InitByTISInputSourceRef(TISInputSourceRef aInputSource);
+  void InitByLanguage(CFStringRef aLanguage);
+
+  /**
+   * If the instance is initialized with a keyboard layout input source,
+   * returns it.
+   * If the instance is initialized with an IME mode input source, the result
+   * references the keyboard layout for the IME mode.  However, this can be
+   * initialized only when the IME mode is actually selected.  I.e, if IME mode
+   * input source is initialized with LayoutID or SourceID, this returns null.
+   */
+  TISInputSourceRef GetKeyboardLayoutInputSource() const {
+    return mKeyboardLayout;
+  }
+  const UCKeyboardLayout* GetUCKeyboardLayout();
+
+  bool IsOpenedIMEMode();
+  bool IsIMEMode();
+  bool IsKeyboardLayout();
+
+  bool IsASCIICapable() {
+    NS_ENSURE_TRUE(mInputSource, false);
+    return GetBoolProperty(kTISPropertyInputSourceIsASCIICapable);
+  }
+
+  bool IsEnabled() {
+    NS_ENSURE_TRUE(mInputSource, false);
+    return GetBoolProperty(kTISPropertyInputSourceIsEnabled);
+  }
+
+  bool GetLanguageList(CFArrayRef& aLanguageList);
+  bool GetPrimaryLanguage(CFStringRef& aPrimaryLanguage);
+  bool GetPrimaryLanguage(nsAString& aPrimaryLanguage);
+
+  bool GetLocalizedName(CFStringRef& aName) {
+    NS_ENSURE_TRUE(mInputSource, false);
+    return GetStringProperty(kTISPropertyLocalizedName, aName);
+  }
+
+  bool GetLocalizedName(nsAString& aName) {
+    NS_ENSURE_TRUE(mInputSource, false);
+    return GetStringProperty(kTISPropertyLocalizedName, aName);
+  }
+
+  bool GetInputSourceID(CFStringRef& aID) {
+    NS_ENSURE_TRUE(mInputSource, false);
+    return GetStringProperty(kTISPropertyInputSourceID, aID);
+  }
+
+  bool GetInputSourceID(nsAString& aID) {
+    NS_ENSURE_TRUE(mInputSource, false);
+    return GetStringProperty(kTISPropertyInputSourceID, aID);
+  }
+
+  bool GetBundleID(CFStringRef& aBundleID) {
+    NS_ENSURE_TRUE(mInputSource, false);
+    return GetStringProperty(kTISPropertyBundleID, aBundleID);
+  }
+
+  bool GetBundleID(nsAString& aBundleID) {
+    NS_ENSURE_TRUE(mInputSource, false);
+    return GetStringProperty(kTISPropertyBundleID, aBundleID);
+  }
+
+  bool GetInputSourceType(CFStringRef& aType) {
+    NS_ENSURE_TRUE(mInputSource, false);
+    return GetStringProperty(kTISPropertyInputSourceType, aType);
+  }
+
+  bool GetInputSourceType(nsAString& aType) {
+    NS_ENSURE_TRUE(mInputSource, false);
+    return GetStringProperty(kTISPropertyInputSourceType, aType);
+  }
+
+  bool IsForRTLLanguage();
+  bool IsForJapaneseLanguage();
+  bool IsInitializedByCurrentInputSource();
+
+  enum {
+    // 40 is an actual result of the ::LMGetKbdType() when we connect an
+    // unknown keyboard and set the keyboard type to ANSI manually on the
+    // set up dialog.
+    eKbdType_ANSI = 40
+  };
+
+  void Select();
+  void Clear();
+
+  /**
+   * InitKeyEvent() initializes aKeyEvent for aNativeKeyEvent.
+   *
+   * @param aNativeKeyEvent       A native key event for which you want to
+   *                              dispatch a Gecko key event.
+   * @param aKeyEvent             The result -- a Gecko key event initialized
+   *                              from the native key event.
+   * @param aIsProcessedByIME     true if aNativeKeyEvent has been handled
+   *                              by IME (but except if the composition was
+   *                              started with dead key).
+   * @param aInsertString         If caller expects that the event will cause
+   *                              a character to be input (say in an editor),
+   *                              the caller should set this.  Otherwise,
+   *                              if caller sets null to this, this method will
+   *                              compute the character to be input from
+   *                              characters of aNativeKeyEvent.
+   */
+  void InitKeyEvent(NSEvent* aNativeKeyEvent, WidgetKeyboardEvent& aKeyEvent,
+                    bool aIsProcessedByIME,
+                    const nsAString* aInsertString = nullptr);
+
+  /**
+   * WillDispatchKeyboardEvent() computes aKeyEvent.mAlternativeCharCodes and
+   * recompute aKeyEvent.mCharCode if it's necessary.
+   *
+   * @param aNativeKeyEvent       A native key event for which you want to
+   *                              dispatch a Gecko key event.
+   * @param aInsertString         If caller expects that the event will cause
+   *                              a character to be input (say in an editor),
+   *                              the caller should set this.  Otherwise,
+   *                              if caller sets null to this, this method will
+   *                              compute the character to be input from
+   *                              characters of aNativeKeyEvent.
+   * @param aIndexOfKeypress      Index of the eKeyPress event.  If a key
+   *                              inputs 2 or more characters, eKeyPress events
+   *                              are dispatched for each character.  This is
+   *                              0 for the first eKeyPress event.
+   * @param aKeyEvent             The result -- a Gecko key event initialized
+   *                              from the native key event.  This must be
+   *                              eKeyPress event.
+   */
+  void WillDispatchKeyboardEvent(NSEvent* aNativeKeyEvent,
+                                 const nsAString* aInsertString,
+                                 uint32_t aIndexOfKeypress,
+                                 WidgetKeyboardEvent& aKeyEvent);
+
+  /**
+   * ComputeGeckoKeyCode() returns Gecko keycode for aNativeKeyCode on current
+   * keyboard layout.
+   *
+   * @param aNativeKeyCode        A native keycode.
+   * @param aKbType               A native Keyboard Type value.  Typically,
+   *                              this is a result of ::LMGetKbdType().
+   * @param aCmdIsPressed         TRUE if Cmd key is pressed.  Otherwise, FALSE.
+   * @return                      The computed Gecko keycode.
+   */
+  uint32_t ComputeGeckoKeyCode(UInt32 aNativeKeyCode, UInt32 aKbType,
+                               bool aCmdIsPressed);
+
+  /**
+   * ComputeGeckoKeyNameIndex() returns Gecko key name index for the key.
+   *
+   * @param aNativeKeyCode        A native keycode.
+   */
+  static KeyNameIndex ComputeGeckoKeyNameIndex(UInt32 aNativeKeyCode);
+
+  /**
+   * ComputeGeckoCodeNameIndex() returns Gecko code name index for the key.
+   *
+   * @param aNativeKeyCode        A native keycode.
+   * @param aKbType               A native Keyboard Type value.  Typically,
+   *                              this is a result of ::LMGetKbdType().
+   */
+  static CodeNameIndex ComputeGeckoCodeNameIndex(UInt32 aNativeKeyCode,
+                                                 UInt32 aKbType);
+
+  /**
+   * TranslateToChar() checks if aNativeKeyEvent is a dead key.
+   *
+   * @param aNativeKeyEvent       A native key event.
+   * @return                      Returns true if the key event is a dead key
+   *                              event.  Otherwise, false.
+   */
+  bool IsDeadKey(NSEvent* aNativeKeyEvent);
+
+ protected:
+  /**
+   * TranslateToString() computes the inputted text from the native keyCode,
+   * modifier flags and keyboard type.
+   *
+   * @param aKeyCode              A native keyCode.
+   * @param aModifiers            Combination of native modifier flags.
+   * @param aKbType               A native Keyboard Type value.  Typically,
+   *                              this is a result of ::LMGetKbdType().
+   * @param aStr                  Result, i.e., inputted text.
+   *                              The result can be two or more characters.
+   * @return                      If succeeded, TRUE.  Otherwise, FALSE.
+   *                              Even if TRUE, aStr can be empty string.
+   */
+  bool TranslateToString(UInt32 aKeyCode, UInt32 aModifiers, UInt32 aKbType,
+                         nsAString& aStr);
+
+  /**
+   * TranslateToChar() computes the inputted character from the native keyCode,
+   * modifier flags and keyboard type.  If two or more characters would be
+   * input, this returns 0.
+   *
+   * @param aKeyCode              A native keyCode.
+   * @param aModifiers            Combination of native modifier flags.
+   * @param aKbType               A native Keyboard Type value.  Typically,
+   *                              this is a result of ::LMGetKbdType().
+   * @return                      If succeeded and the result is one character,
+   *                              returns the charCode of it.  Otherwise,
+   *                              returns 0.
+   */
+  uint32_t TranslateToChar(UInt32 aKeyCode, UInt32 aModifiers, UInt32 aKbType);
+
+  /**
+   * TranslateToChar() checks if aKeyCode with aModifiers is a dead key.
+   *
+   * @param aKeyCode              A native keyCode.
+   * @param aModifiers            Combination of native modifier flags.
+   * @param aKbType               A native Keyboard Type value.  Typically,
+   *                              this is a result of ::LMGetKbdType().
+   * @return                      Returns true if the key with specified
+   *                              modifier state is a dead key.  Otherwise,
+   *                              false.
+   */
+  bool IsDeadKey(UInt32 aKeyCode, UInt32 aModifiers, UInt32 aKbType);
+
+  /**
+   * ComputeInsertString() computes string to be inserted with the key event.
+   *
+   * @param aNativeKeyEvent     The native key event which causes our keyboard
+   *                            event(s).
+   * @param aKeyEvent           A Gecko key event which was partially
+   *                            initialized with aNativeKeyEvent.
+   * @param aInsertString       The string to be inputting by aNativeKeyEvent.
+   *                            This should be specified by InsertText().
+   *                            In other words, if the key event doesn't cause
+   *                            a call of InsertText(), this can be nullptr.
+   * @param aResult             The string which should be set to charCode of
+   *                            keypress event(s).
+   */
+  void ComputeInsertStringForCharCode(NSEvent* aNativeKeyEvent,
+                                      const WidgetKeyboardEvent& aKeyEvent,
+                                      const nsAString* aInsertString,
+                                      nsAString& aResult);
+
+  /**
+   * IsPrintableKeyEvent() returns true if aNativeKeyEvent is caused by
+   * a printable key.  Otherwise, returns false.
+   */
+  bool IsPrintableKeyEvent(NSEvent* aNativeKeyEvent) const;
+
+  /**
+   * GetKbdType() returns physical keyboard type.
+   */
+  UInt32 GetKbdType() const;
+
+  bool GetBoolProperty(const CFStringRef aKey);
+  bool GetStringProperty(const CFStringRef aKey, CFStringRef& aStr);
+  bool GetStringProperty(const CFStringRef aKey, nsAString& aStr);
+
+  TISInputSourceRef mInputSource;
+  TISInputSourceRef mKeyboardLayout;
+  CFArrayRef mInputSourceList;
+  const UCKeyboardLayout* mUCKeyboardLayout;
+  int8_t mIsRTL;
+
+  bool mOverrideKeyboard;
+
+  static TISInputSourceWrapper* sCurrentInputSource;
+};
+
+/**
+ * TextInputHandlerBase is a base class of IMEInputHandler and TextInputHandler.
+ * Utility methods should be implemented this level.
+ */
+
+class TextInputHandlerBase : public TextEventDispatcherListener {
+ public:
+  /**
+   * Other TextEventDispatcherListener methods should be implemented in
+   * IMEInputHandler.
+   */
+  NS_DECL_ISUPPORTS
+
+  /**
+   * DispatchEvent() dispatches aEvent on mWidget.
+   *
+   * @param aEvent                An event which you want to dispatch.
+   * @return                      TRUE if the event is consumed by web contents
+   *                              or chrome contents.  Otherwise, FALSE.
+   */
+  bool DispatchEvent(WidgetGUIEvent& aEvent);
+
+  /**
+   * SetSelection() dispatches eSetSelection event for the aRange.
+   *
+   * @param aRange                The range which will be selected.
+   * @return                      TRUE if setting selection is succeeded and
+   *                              the widget hasn't been destroyed.
+   *                              Otherwise, FALSE.
+   */
+  bool SetSelection(NSRange& aRange);
+
+  /**
+   * InitKeyEvent() initializes aKeyEvent for aNativeKeyEvent.
+   *
+   * @param aNativeKeyEvent       A native key event for which you want to
+   *                              dispatch a Gecko key event.
+   * @param aKeyEvent             The result -- a Gecko key event initialized
+   *                              from the native key event.
+   * @param aIsProcessedByIME     true if aNativeKeyEvent has been handled
+   *                              by IME (but except if the composition was
+   *                              started with dead key).
+   * @param aInsertString         If caller expects that the event will cause
+   *                              a character to be input (say in an editor),
+   *                              the caller should set this.  Otherwise,
+   *                              if caller sets null to this, this method will
+   *                              compute the character to be input from
+   *                              characters of aNativeKeyEvent.
+   */
+  void InitKeyEvent(NSEvent* aNativeKeyEvent, WidgetKeyboardEvent& aKeyEvent,
+                    bool aIsProcessedByIME,
+                    const nsAString* aInsertString = nullptr);
+
+  /**
+   * SynthesizeNativeKeyEvent() is an implementation of
+   * nsIWidget::SynthesizeNativeKeyEvent().  See the document in nsIWidget.h
+   * for the detail.
+   */
+  nsresult SynthesizeNativeKeyEvent(int32_t aNativeKeyboardLayout,
+                                    int32_t aNativeKeyCode,
+                                    uint32_t aModifierFlags,
+                                    const nsAString& aCharacters,
+                                    const nsAString& aUnmodifiedCharacters);
+
+  /**
+   * Utility method intended for testing. Attempts to construct a native key
+   * event that would have been generated during an actual key press. This
+   * *does not dispatch* the native event. Instead, it is attached to the
+   * |mNativeKeyEvent| field of the Gecko event that is passed in.
+   * @param aKeyEvent  Gecko key event to attach the native event to
+   */
+  NS_IMETHOD AttachNativeKeyEvent(WidgetKeyboardEvent& aKeyEvent);
+
+  /**
+   * GetWindowLevel() returns the window level of current focused (in Gecko)
+   * window.  E.g., if an <input> element in XUL panel has focus, this returns
+   * the XUL panel's window level.
+   */
+  NSInteger GetWindowLevel();
+
+  /**
+   * IsSpecialGeckoKey() checks whether aNativeKeyCode is mapped to a special
+   * Gecko keyCode.  A key is "special" if it isn't used for text input.
+   *
+   * @param aNativeKeyCode        A native keycode.
+   * @return                      If the keycode is mapped to a special key,
+   *                              TRUE.  Otherwise, FALSE.
+   */
+  static bool IsSpecialGeckoKey(UInt32 aNativeKeyCode);
+
+  /**
+   * EnableSecureEventInput() and DisableSecureEventInput() wrap the Carbon
+   * Event Manager APIs with the same names.  In addition they keep track of
+   * how many times we've called them (in the same process) -- unlike the
+   * Carbon Event Manager APIs, which only keep track of how many times they've
+   * been called from any and all processes.
+   *
+   * The Carbon Event Manager's IsSecureEventInputEnabled() returns whether
+   * secure event input mode is enabled (in any process).  This class's
+   * IsSecureEventInputEnabled() returns whether we've made any calls to
+   * EnableSecureEventInput() that are not (yet) offset by the calls we've
+   * made to DisableSecureEventInput().
+   */
+  static void EnableSecureEventInput();
+  static void DisableSecureEventInput();
+  static bool IsSecureEventInputEnabled();
+
+  /**
+   * EnsureSecureEventInputDisabled() calls DisableSecureEventInput() until
+   * our call count becomes 0.
+   */
+  static void EnsureSecureEventInputDisabled();
+
+ public:
+  /**
+   * mWidget must not be destroyed without OnDestroyWidget being called.
+   *
+   * @param aDestroyingWidget     Destroying widget.  This might not be mWidget.
+   * @return                      This result doesn't have any meaning for
+   *                              callers.  When aDstroyingWidget isn't the same
+   *                              as mWidget, FALSE.  Then, inherited methods in
+   *                              sub classes should return from this method
+   *                              without cleaning up.
+   */
+  virtual bool OnDestroyWidget(nsChildView* aDestroyingWidget);
+
+ protected:
+  // The creator of this instance, client and its text event dispatcher.
+  // These members must not be nullptr after initialized until
+  // OnDestroyWidget() is called.
+  nsChildView* mWidget;  // [WEAK]
+  RefPtr<TextEventDispatcher> mDispatcher;
+
+  // The native view for mWidget.
+  // This view handles the actual text inputting.
+  NSView<mozView>* mView;  // [STRONG]
+
+  TextInputHandlerBase(nsChildView* aWidget, NSView<mozView>* aNativeView);
+  virtual ~TextInputHandlerBase();
+
+  bool Destroyed() { return !mWidget; }
+
+  /**
+   * mCurrentKeyEvent indicates what key event we are handling.  While
+   * handling a native keydown event, we need to store the event for insertText,
+   * doCommandBySelector and various action message handlers of NSResponder
+   * such as [NSResponder insertNewline:sender].
+   */
+  struct KeyEventState {
+    // Handling native key event
+    NSEvent* mKeyEvent;
+    // String specified by InsertText().  This is not null only during a
+    // call of InsertText().
+    nsAString* mInsertString;
+    // String which are included in [mKeyEvent characters] and already handled
+    // by InsertText() call(s).
+    nsString mInsertedString;
+    // Unique id associated with a keydown / keypress event. It's ok if this
+    // wraps over long periods.
+    uint32_t mUniqueId;
+    // Whether keydown event was dispatched for mKeyEvent.
+    bool mKeyDownDispatched;
+    // Whether keydown event was consumed by web contents or chrome contents.
+    bool mKeyDownHandled;
+    // Whether keypress event was dispatched for mKeyEvent.
+    bool mKeyPressDispatched;
+    // Whether keypress event was consumed by web contents or chrome contents.
+    bool mKeyPressHandled;
+    // Whether the key event causes other key events via IME or something.
+    bool mCausedOtherKeyEvents;
+    // Whether the key event causes composition change or committing
+    // composition.  So, even if InsertText() is called, this may be false
+    // if it dispatches keypress event.
+    bool mCompositionDispatched;
+
+    KeyEventState() : mKeyEvent(nullptr), mUniqueId(0) { Clear(); }
+
+    explicit KeyEventState(NSEvent* aNativeKeyEvent, uint32_t aUniqueId = 0)
+        : mKeyEvent(nullptr), mUniqueId(0) {
+      Clear();
+      Set(aNativeKeyEvent, aUniqueId);
+    }
+
+    KeyEventState(const KeyEventState& aOther) = delete;
+
+    ~KeyEventState() { Clear(); }
+
+    void Set(NSEvent* aNativeKeyEvent, uint32_t aUniqueId = 0) {
+      MOZ_ASSERT(aNativeKeyEvent, "aNativeKeyEvent must not be NULL");
+      Clear();
+      mKeyEvent = [aNativeKeyEvent retain];
+      mUniqueId = aUniqueId;
+    }
+
+    void Clear() {
+      if (mKeyEvent) {
+        [mKeyEvent release];
+        mKeyEvent = nullptr;
+        mUniqueId = 0;
+      }
+      mInsertString = nullptr;
+      mInsertedString.Truncate();
+      mKeyDownDispatched = false;
+      mKeyDownHandled = false;
+      mKeyPressDispatched = false;
+      mKeyPressHandled = false;
+      mCausedOtherKeyEvents = false;
+      mCompositionDispatched = false;
+    }
+
+    bool IsDefaultPrevented() const {
+      return mKeyDownHandled || mKeyPressHandled || mCausedOtherKeyEvents ||
+             mCompositionDispatched;
+    }
+
+    bool CanDispatchKeyDownEvent() const { return !mKeyDownDispatched; }
+
+    bool CanDispatchKeyPressEvent() const {
+      return !mKeyPressDispatched && !IsDefaultPrevented();
+    }
+
+    bool CanHandleCommand() const {
+      return !mKeyDownHandled && !mKeyPressHandled;
+    }
+
+    bool IsProperKeyEvent(Command aCommand) const {
+      if (NS_WARN_IF(!mKeyEvent)) {
+        return false;
+      }
+      KeyNameIndex keyNameIndex =
+          TISInputSourceWrapper::ComputeGeckoKeyNameIndex([mKeyEvent keyCode]);
+      Modifiers modifiers =
+          nsCocoaUtils::ModifiersForEvent(mKeyEvent) &
+          (MODIFIER_SHIFT | MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+      switch (aCommand) {
+        case Command::InsertLineBreak:
+          return keyNameIndex == KEY_NAME_INDEX_Enter &&
+                 modifiers == MODIFIER_CONTROL;
+        case Command::InsertParagraph:
+          return keyNameIndex == KEY_NAME_INDEX_Enter &&
+                 modifiers == MODIFIER_NONE;
+        case Command::DeleteCharBackward:
+          return keyNameIndex == KEY_NAME_INDEX_Backspace &&
+                 modifiers == MODIFIER_NONE;
+        case Command::DeleteToBeginningOfLine:
+          return keyNameIndex == KEY_NAME_INDEX_Backspace &&
+                 modifiers == MODIFIER_META;
+        case Command::DeleteWordBackward:
+          return keyNameIndex == KEY_NAME_INDEX_Backspace &&
+                 modifiers == MODIFIER_ALT;
+        case Command::DeleteCharForward:
+          return keyNameIndex == KEY_NAME_INDEX_Delete &&
+                 modifiers == MODIFIER_NONE;
+        case Command::DeleteWordForward:
+          return keyNameIndex == KEY_NAME_INDEX_Delete &&
+                 modifiers == MODIFIER_ALT;
+        case Command::InsertTab:
+          return keyNameIndex == KEY_NAME_INDEX_Tab &&
+                 modifiers == MODIFIER_NONE;
+        case Command::InsertBacktab:
+          return keyNameIndex == KEY_NAME_INDEX_Tab &&
+                 modifiers == MODIFIER_SHIFT;
+        case Command::CharNext:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowRight &&
+                 modifiers == MODIFIER_NONE;
+        case Command::SelectCharNext:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowRight &&
+                 modifiers == MODIFIER_SHIFT;
+        case Command::WordNext:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowRight &&
+                 modifiers == MODIFIER_ALT;
+        case Command::SelectWordNext:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowRight &&
+                 modifiers == (MODIFIER_ALT | MODIFIER_SHIFT);
+        case Command::EndLine:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowRight &&
+                 modifiers == MODIFIER_META;
+        case Command::SelectEndLine:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowRight &&
+                 modifiers == (MODIFIER_META | MODIFIER_SHIFT);
+        case Command::CharPrevious:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowLeft &&
+                 modifiers == MODIFIER_NONE;
+        case Command::SelectCharPrevious:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowLeft &&
+                 modifiers == MODIFIER_SHIFT;
+        case Command::WordPrevious:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowLeft &&
+                 modifiers == MODIFIER_ALT;
+        case Command::SelectWordPrevious:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowLeft &&
+                 modifiers == (MODIFIER_ALT | MODIFIER_SHIFT);
+        case Command::BeginLine:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowLeft &&
+                 modifiers == MODIFIER_META;
+        case Command::SelectBeginLine:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowLeft &&
+                 modifiers == (MODIFIER_META | MODIFIER_SHIFT);
+        case Command::LinePrevious:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowUp &&
+                 modifiers == MODIFIER_NONE;
+        case Command::SelectLinePrevious:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowUp &&
+                 modifiers == MODIFIER_SHIFT;
+        case Command::MoveTop:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowUp &&
+                 modifiers == MODIFIER_META;
+        case Command::SelectTop:
+          return (keyNameIndex == KEY_NAME_INDEX_ArrowUp &&
+                  modifiers == (MODIFIER_META | MODIFIER_SHIFT)) ||
+                 (keyNameIndex == KEY_NAME_INDEX_Home &&
+                  modifiers == MODIFIER_SHIFT);
+        case Command::LineNext:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowDown &&
+                 modifiers == MODIFIER_NONE;
+        case Command::SelectLineNext:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowDown &&
+                 modifiers == MODIFIER_SHIFT;
+        case Command::MoveBottom:
+          return keyNameIndex == KEY_NAME_INDEX_ArrowDown &&
+                 modifiers == MODIFIER_META;
+        case Command::SelectBottom:
+          return (keyNameIndex == KEY_NAME_INDEX_ArrowDown &&
+                  modifiers == (MODIFIER_META | MODIFIER_SHIFT)) ||
+                 (keyNameIndex == KEY_NAME_INDEX_End &&
+                  modifiers == MODIFIER_SHIFT);
+        case Command::ScrollPageUp:
+          return keyNameIndex == KEY_NAME_INDEX_PageUp &&
+                 modifiers == MODIFIER_NONE;
+        case Command::SelectPageUp:
+          return keyNameIndex == KEY_NAME_INDEX_PageUp &&
+                 modifiers == MODIFIER_SHIFT;
+        case Command::ScrollPageDown:
+          return keyNameIndex == KEY_NAME_INDEX_PageDown &&
+                 modifiers == MODIFIER_NONE;
+        case Command::SelectPageDown:
+          return keyNameIndex == KEY_NAME_INDEX_PageDown &&
+                 modifiers == MODIFIER_SHIFT;
+        case Command::ScrollBottom:
+          return keyNameIndex == KEY_NAME_INDEX_End &&
+                 modifiers == MODIFIER_NONE;
+        case Command::ScrollTop:
+          return keyNameIndex == KEY_NAME_INDEX_Home &&
+                 modifiers == MODIFIER_NONE;
+        case Command::CancelOperation:
+          return (keyNameIndex == KEY_NAME_INDEX_Escape &&
+                  (modifiers == MODIFIER_NONE ||
+                   modifiers == MODIFIER_SHIFT)) ||
+                 ([mKeyEvent keyCode] == kVK_ANSI_Period &&
+                  modifiers == MODIFIER_META);
+        case Command::Complete:
+          return keyNameIndex == KEY_NAME_INDEX_Escape &&
+                 (modifiers == MODIFIER_ALT ||
+                  modifiers == (MODIFIER_ALT | MODIFIER_SHIFT));
+        default:
+          return false;
+      }
+    }
+
+    void InitKeyEvent(TextInputHandlerBase* aHandler,
+                      WidgetKeyboardEvent& aKeyEvent, bool aIsProcessedByIME);
+
+    /**
+     * GetUnhandledString() returns characters of the event which have not been
+     * handled with InsertText() yet. For example, if there is a composition
+     * caused by a dead key press like '`' and it's committed by some key
+     * combinations like |Cmd+v|, then, the |v|'s KeyDown event's |characters|
+     * is |`v|.  Then, after |`| is committed with a call of InsertString(),
+     * this returns only 'v'.
+     */
+    void GetUnhandledString(nsAString& aUnhandledString) const;
+  };
+
+  /**
+   * Helper classes for guaranteeing cleaning mCurrentKeyEvent
+   */
+  class AutoKeyEventStateCleaner {
+   public:
+    explicit AutoKeyEventStateCleaner(TextInputHandlerBase* aHandler)
+        : mHandler(aHandler) {}
+
+    ~AutoKeyEventStateCleaner() { mHandler->RemoveCurrentKeyEvent(); }
+
+   private:
+    RefPtr<TextInputHandlerBase> mHandler;
+  };
+
+  class MOZ_STACK_CLASS AutoInsertStringClearer {
+   public:
+    explicit AutoInsertStringClearer(KeyEventState* aState) : mState(aState) {}
+    ~AutoInsertStringClearer();
+
+   private:
+    KeyEventState* mState;
+  };
+
+  /**
+   * mCurrentKeyEvents stores all key events which are being processed.
+   * When we call interpretKeyEvents, IME may generate other key events.
+   * mCurrentKeyEvents[0] is the latest key event.
+   */
+  nsTArray<KeyEventState*> mCurrentKeyEvents;
+
+  /**
+   * mFirstKeyEvent must be used for first key event.  This member prevents
+   * memory fragmentation for most key events.
+   */
+  KeyEventState mFirstKeyEvent;
+
+  /**
+   * PushKeyEvent() adds the current key event to mCurrentKeyEvents.
+   */
+  KeyEventState* PushKeyEvent(NSEvent* aNativeKeyEvent,
+                              uint32_t aUniqueId = 0) {
+    uint32_t nestCount = mCurrentKeyEvents.Length();
+    for (uint32_t i = 0; i < nestCount; i++) {
+      // When the key event is caused by another key event, all key events
+      // which are being handled should be marked as "consumed".
+      mCurrentKeyEvents[i]->mCausedOtherKeyEvents = true;
+    }
+
+    KeyEventState* keyEvent = nullptr;
+    if (nestCount == 0) {
+      mFirstKeyEvent.Set(aNativeKeyEvent, aUniqueId);
+      keyEvent = &mFirstKeyEvent;
+    } else {
+      keyEvent = new KeyEventState(aNativeKeyEvent, aUniqueId);
+    }
+    return *mCurrentKeyEvents.AppendElement(keyEvent);
+  }
+
+  /**
+   * RemoveCurrentKeyEvent() removes the current key event from
+   * mCurrentKeyEvents.
+   */
+  void RemoveCurrentKeyEvent() {
+    NS_ASSERTION(mCurrentKeyEvents.Length() > 0,
+                 "RemoveCurrentKeyEvent() is called unexpectedly");
+    KeyEventState* keyEvent = mCurrentKeyEvents.PopLastElement();
+    if (keyEvent == &mFirstKeyEvent) {
+      keyEvent->Clear();
+    } else {
+      delete keyEvent;
+    }
+  }
+
+  /**
+   * GetCurrentKeyEvent() returns current processing key event.
+   */
+  KeyEventState* GetCurrentKeyEvent() {
+    if (mCurrentKeyEvents.Length() == 0) {
+      return nullptr;
+    }
+    return mCurrentKeyEvents[mCurrentKeyEvents.Length() - 1];
+  }
+
+  struct KeyboardLayoutOverride final {
+    int32_t mKeyboardLayout;
+    bool mOverrideEnabled;
+
+    KeyboardLayoutOverride() : mKeyboardLayout(0), mOverrideEnabled(false) {}
+  };
+
+  const KeyboardLayoutOverride& KeyboardLayoutOverrideRef() const {
+    return mKeyboardOverride;
+  }
+
+  /**
+   * IsPrintableChar() checks whether the unicode character is
+   * a non-printable ASCII character or not.  Note that this returns
+   * TRUE even if aChar is a non-printable UNICODE character.
+   *
+   * @param aChar                 A unicode character.
+   * @return                      TRUE if aChar is a printable ASCII character
+   *                              or a unicode character.  Otherwise, i.e,
+   *                              if aChar is a non-printable ASCII character,
+   *                              FALSE.
+   */
+  static bool IsPrintableChar(char16_t aChar);
+
+  /**
+   * IsNormalCharInputtingEvent() checks whether aNativeEvent causes text input.
+   *
+   * @param aNativeEvent          A key event.
+   * @return                      TRUE if the key event causes text input.
+   *                              Otherwise, FALSE.
+   */
+  static bool IsNormalCharInputtingEvent(NSEvent* aNativeEvent);
+
+  /**
+   * IsModifierKey() checks whether the native keyCode is for a modifier key.
+   *
+   * @param aNativeKeyCode        A native keyCode.
+   * @return                      TRUE if aNativeKeyCode is for a modifier key.
+   *                              Otherwise, FALSE.
+   */
+  static bool IsModifierKey(UInt32 aNativeKeyCode);
+
+ private:
+  KeyboardLayoutOverride mKeyboardOverride;
+
+  static int32_t sSecureEventInputCount;
+};
+
+/**
+ * IMEInputHandler manages:
+ *   1. The IME/keyboard layout statement of nsChildView.
+ *   2. The IME composition statement of nsChildView.
+ * And also provides the methods which controls the current IME transaction of
+ * the instance.
+ *
+ * Note that an nsChildView handles one or more NSView's events.  E.g., even if
+ * a text editor on XUL panel element, the input events handled on the parent
+ * (or its ancestor) widget handles it (the native focus is set to it).  The
+ * actual focused view is notified by OnFocusChangeInGecko.
+ */
+
+class IMEInputHandler : public TextInputHandlerBase {
+ public:
+  // TextEventDispatcherListener methods
+  NS_IMETHOD NotifyIME(TextEventDispatcher* aTextEventDispatcher,
+                       const IMENotification& aNotification) override;
+  NS_IMETHOD_(IMENotificationRequests) GetIMENotificationRequests() override;
+  NS_IMETHOD_(void)
+  OnRemovedFrom(TextEventDispatcher* aTextEventDispatcher) override;
+  NS_IMETHOD_(void)
+  WillDispatchKeyboardEvent(TextEventDispatcher* aTextEventDispatcher,
+                            WidgetKeyboardEvent& aKeyboardEvent,
+                            uint32_t aIndexOfKeypress, void* aData) override;
+
+ public:
+  virtual bool OnDestroyWidget(nsChildView* aDestroyingWidget) override;
+
+  virtual void OnFocusChangeInGecko(bool aFocus);
+
+  void OnSelectionChange(const IMENotification& aIMENotification);
+  void OnLayoutChange();
+
+  /**
+   * Call [NSTextInputContext handleEvent] for mouse event support of IME
+   */
+  bool OnHandleEvent(NSEvent* aEvent);
+
+  /**
+   * SetMarkedText() is a handler of setMarkedText of NSTextInput.
+   *
+   * @param aAttrString           This mut be an instance of NSAttributedString.
+   *                              If the aString parameter to
+   *                              [ChildView setMarkedText:setSelectedRange:]
+   *                              isn't an instance of NSAttributedString,
+   *                              create an NSAttributedString from it and pass
+   *                              that instead.
+   * @param aSelectedRange        Current selected range (or caret position).
+   * @param aReplacementRange     The range which will be replaced with the
+   *                              aAttrString instead of current marked range.
+   */
+  void SetMarkedText(NSAttributedString* aAttrString, NSRange& aSelectedRange,
+                     NSRange* aReplacementRange = nullptr);
+
+  /**
+   * GetAttributedSubstringFromRange() returns an NSAttributedString instance
+   * which is allocated as autorelease for aRange.
+   *
+   * @param aRange                The range of string which you want.
+   * @param aActualRange          The actual range of the result.
+   * @return                      The string in aRange.  If the string is empty,
+   *                              this returns nil.  If succeeded, this returns
+   *                              an instance which is allocated as autorelease.
+   *                              If this has some troubles, returns nil.
+   */
+  NSAttributedString* GetAttributedSubstringFromRange(
+      NSRange& aRange, NSRange* aActualRange = nullptr);
+
+  /**
+   * SelectedRange() returns current selected range.
+   *
+   * @return                      If an editor has focus, this returns selection
+   *                              range in the editor.  Otherwise, this returns
+   *                              selection range  in the focused document.
+   */
+  NSRange SelectedRange();
+
+  /**
+   * DrawsVerticallyForCharacterAtIndex() returns whether the character at
+   * the given index is being rendered vertically.
+   *
+   * @param aCharIndex            The character offset to query.
+   *
+   * @return                      True if writing-mode is vertical at the given
+   *                              character offset; otherwise false.
+   */
+  bool DrawsVerticallyForCharacterAtIndex(uint32_t aCharIndex);
+
+  /**
+   * FirstRectForCharacterRange() returns first *character* rect in the range.
+   * Cocoa needs the first line rect in the range, but we cannot compute it
+   * on current implementation.
+   *
+   * @param aRange                A range of text to examine.  Its position is
+   *                              an offset from the beginning of the focused
+   *                              editor or document.
+   * @param aActualRange          If this is not null, this returns the actual
+   *                              range used for computing the result.
+   * @return                      An NSRect containing the first character in
+   *                              aRange, in screen coordinates.
+   *                              If the length of aRange is 0, the width will
+   *                              be 0.
+   */
+  NSRect FirstRectForCharacterRange(NSRange& aRange,
+                                    NSRange* aActualRange = nullptr);
+
+  /**
+   * CharacterIndexForPoint() returns an offset of a character at aPoint.
+   * XXX This isn't implemented, always returns 0.
+   *
+   * @param                       The point in screen coordinates.
+   * @return                      The offset of the character at aPoint from
+   *                              the beginning of the focused editor or
+   *                              document.
+   */
+  NSUInteger CharacterIndexForPoint(NSPoint& aPoint);
+
+  /**
+   * GetValidAttributesForMarkedText() returns attributes which we support.
+   *
+   * @return                      Always empty array for now.
+   */
+  NSArray* GetValidAttributesForMarkedText();
+
+  bool HasMarkedText();
+  NSRange MarkedRange();
+
+  bool IsIMEComposing() { return mIsIMEComposing; }
+  bool IsDeadKeyComposing() { return mIsDeadKeyComposing; }
+  bool IsIMEOpened();
+  bool IsIMEEnabled() { return mIsIMEEnabled; }
+  bool IsASCIICapableOnly() { return mIsASCIICapableOnly; }
+  bool IsEditableContent() const {
+    return mIsIMEEnabled || mIsASCIICapableOnly;
+  }
+  bool IgnoreIMECommit() { return mIgnoreIMECommit; }
+
+  void CommitIMEComposition();
+  void CancelIMEComposition();
+
+  void EnableIME(bool aEnableIME);
+  void SetIMEOpenState(bool aOpen);
+  void SetASCIICapableOnly(bool aASCIICapableOnly);
+
+  /**
+   * True if OSX believes that our view has keyboard focus.
+   */
+  bool IsFocused();
+
+  static CFArrayRef CreateAllIMEModeList();
+  static void DebugPrintAllIMEModes();
+
+  // Don't use ::TSMGetActiveDocument() API directly, the document may not
+  // be what you want.
+  static TSMDocumentID GetCurrentTSMDocumentID();
+
+ protected:
+  // We cannot do some jobs in the given stack by some reasons.
+  // Following flags and the timer provide the execution pending mechanism,
+  // See the comment in nsCocoaTextInputHandler.mm.
+  nsCOMPtr<nsITimer> mTimer;
+  enum { kNotifyIMEOfFocusChangeInGecko = 1, kSyncASCIICapableOnly = 2 };
+  uint32_t mPendingMethods;
+
+  IMEInputHandler(nsChildView* aWidget, NSView<mozView>* aNativeView);
+  virtual ~IMEInputHandler();
+
+  void ResetTimer();
+
+  virtual void ExecutePendingMethods();
+
+  /**
+   * InsertTextAsCommittingComposition() commits current composition.  If there
+   * is no composition, this starts a composition and commits it immediately.
+   *
+   * @param aString               A string which is committed.
+   * @param aReplacementRange     The range which will be replaced with the
+   *                              aAttrString instead of current selection.
+   */
+  void InsertTextAsCommittingComposition(NSString* aString,
+                                         NSRange* aReplacementRange);
+
+  /**
+   * MaybeDispatchCurrentKeydownEvent() dispatches eKeyDown event for current
+   * key event.  If eKeyDown for current key event has already been dispatched,
+   * this does nothing.
+   *
+   * @param aIsProcessedByIME   true if current key event is handled by IME.
+   * @return                    true if the caller can continue to handle
+   *                            current key event.  Otherwise, false.  E.g.,
+   *                            focus is moved, the widget has been destroyed
+   *                            or something.
+   */
+  bool MaybeDispatchCurrentKeydownEvent(bool aIsProcessedByIME);
+
+ private:
+  // If mIsIMEComposing is true, the composition string is stored here.
+  NSString* mIMECompositionString;
+  // If mIsIMEComposing is true, the start offset of the composition string.
+  uint32_t mIMECompositionStart;
+
+  NSRange mMarkedRange;
+  NSRange mSelectedRange;
+
+  NSRange mRangeForWritingMode;  // range within which mWritingMode applies
+  mozilla::WritingMode mWritingMode;
+
+  bool mIsIMEComposing;
+  // If the composition started with dead key, mIsDeadKeyComposing is set to
+  // true.
+  bool mIsDeadKeyComposing;
+  bool mIsIMEEnabled;
+  bool mIsASCIICapableOnly;
+  bool mIgnoreIMECommit;
+  bool mIMEHasFocus;
+
+  void KillIMEComposition();
+  void SendCommittedText(NSString* aString);
+  void OpenSystemPreferredLanguageIME();
+
+  // Pending methods
+  void NotifyIMEOfFocusChangeInGecko();
+  void SyncASCIICapableOnly();
+
+  static bool sStaticMembersInitialized;
+  static CFStringRef sLatestIMEOpenedModeInputSourceID;
+  static void InitStaticMembers();
+  static void OnCurrentTextInputSourceChange(CFNotificationCenterRef aCenter,
+                                             void* aObserver, CFStringRef aName,
+                                             const void* aObject,
+                                             CFDictionaryRef aUserInfo);
+
+  static void FlushPendingMethods(nsITimer* aTimer, void* aClosure);
+
+  /**
+   * ConvertToTextRangeStyle converts the given native underline style to
+   * our defined text range type.
+   *
+   * @param aUnderlineStyle       NSUnderlineStyleSingle or
+   *                              NSUnderlineStyleThick.
+   * @param aSelectedRange        Current selected range (or caret position).
+   * @return                      NS_TEXTRANGE_*.
+   */
+  TextRangeType ConvertToTextRangeType(uint32_t aUnderlineStyle,
+                                       NSRange& aSelectedRange);
+
+  /**
+   * GetRangeCount() computes the range count of aAttrString.
+   *
+   * @param aAttrString           An NSAttributedString instance whose number of
+   *                              NSUnderlineStyleAttributeName ranges you with
+   *                              to know.
+   * @return                      The count of NSUnderlineStyleAttributeName
+   *                              ranges in aAttrString.
+   */
+  uint32_t GetRangeCount(NSAttributedString* aString);
+
+  /**
+   * CreateTextRangeArray() returns text ranges for clauses and/or caret.
+   *
+   * @param aAttrString           An NSAttributedString instance which indicates
+   *                              current composition string.
+   * @param aSelectedRange        Current selected range (or caret position).
+   * @return                      The result is set to the
+   *                              NSUnderlineStyleAttributeName ranges in
+   *                              aAttrString.
+   */
+  already_AddRefed<mozilla::TextRangeArray> CreateTextRangeArray(
+      NSAttributedString* aAttrString, NSRange& aSelectedRange);
+
+  /**
+   * DispatchCompositionStartEvent() dispatches a compositionstart event and
+   * initializes the members indicating composition state.
+   *
+   * @return                      true if it can continues handling composition.
+   *                              Otherwise, e.g., canceled by the web page,
+   *                              this returns false.
+   */
+  bool DispatchCompositionStartEvent();
+
+  /**
+   * DispatchCompositionChangeEvent() dispatches a compositionchange event on
+   * mWidget and modifies the members indicating composition state.
+   *
+   * @param aText                 User text input.
+   * @param aAttrString           An NSAttributedString instance which indicates
+   *                              current composition string.
+   * @param aSelectedRange        Current selected range (or caret position).
+   *
+   * @return                      true if it can continues handling composition.
+   *                              Otherwise, e.g., canceled by the web page,
+   *                              this returns false.
+   */
+  bool DispatchCompositionChangeEvent(const nsString& aText,
+                                      NSAttributedString* aAttrString,
+                                      NSRange& aSelectedRange);
+
+  /**
+   * DispatchCompositionCommitEvent() dispatches a compositioncommit event or
+   * compositioncommitasis event.  If aCommitString is null, dispatches
+   * compositioncommitasis event.  I.e., if aCommitString is null, this
+   * commits the composition with the last data.  Otherwise, commits the
+   * composition with aCommitString value.
+   *
+   * @return                      true if the widget isn't destroyed.
+   *                              Otherwise, false.
+   */
+  bool DispatchCompositionCommitEvent(const nsAString* aCommitString = nullptr);
+
+  // The focused IME handler.  Please note that the handler might lost the
+  // actual focus by deactivating the application.  If we are active, this
+  // must have the actual focused handle.
+  // We cannot access to the NSInputManager during we aren't active, so, the
+  // focused handler can have an IME transaction even if we are deactive.
+  static IMEInputHandler* sFocusedIMEHandler;
+
+  static bool sCachedIsForRTLLangage;
+};
+
+/**
+ * TextInputHandler implements the NSTextInput protocol.
+ */
+class TextInputHandler : public IMEInputHandler {
+ public:
+  static NSUInteger sLastModifierState;
+
+  static CFArrayRef CreateAllKeyboardLayoutList();
+  static void DebugPrintAllKeyboardLayouts();
+
+  TextInputHandler(nsChildView* aWidget, NSView<mozView>* aNativeView);
+  virtual ~TextInputHandler();
+
+  /**
+   * KeyDown event handler.
+   *
+   * @param aNativeEvent          A native NSEventTypeKeyDown event.
+   * @param aUniqueId             A unique ID for the event.
+   * @return                      TRUE if the event is dispatched to web
+   *                              contents or chrome contents. Otherwise, FALSE.
+   */
+  bool HandleKeyDownEvent(NSEvent* aNativeEvent, uint32_t aUniqueId);
+
+  /**
+   * KeyUp event handler.
+   *
+   * @param aNativeEvent          A native NSEventTypeKeyUp event.
+   */
+  void HandleKeyUpEvent(NSEvent* aNativeEvent);
+
+  /**
+   * FlagsChanged event handler.
+   *
+   * @param aNativeEvent          A native NSEventTypeFlagsChanged event.
+   */
+  void HandleFlagsChanged(NSEvent* aNativeEvent);
+
+  /**
+   * Insert the string to content.  I.e., this is a text input event handler.
+   * If this is called during keydown event handling, this may dispatch a
+   * eKeyPress event.  If this is called during composition, this commits
+   * the composition by the aAttrString.
+   *
+   * @param aString               An inserted string.
+   * @param aReplacementRange     The range which will be replaced with the
+   *                              aAttrString instead of current selection.
+   */
+  void InsertText(NSString* aString, NSRange* aReplacementRange = nullptr);
+
+  /**
+   * Handles aCommand.  This may cause dispatching an eKeyPress event.
+   *
+   * @param aCommand    The command which receives from Cocoa.
+   * @return            true if this handles the command even if it does
+   *                    nothing actually.  Otherwise, false.
+   */
+  bool HandleCommand(Command aCommand);
+
+  /**
+   * doCommandBySelector event handler.
+   *
+   * @param aSelector             A selector of the command.
+   * @return                      TRUE if the command is consumed.  Otherwise,
+   *                              FALSE.
+   */
+  bool DoCommandBySelector(const char* aSelector);
+
+  /**
+   * KeyPressWasHandled() checks whether keypress event was handled or not.
+   *
+   * @return                      TRUE if keypress event for latest native key
+   *                              event was handled.  Otherwise, FALSE.
+   *                              If this handler isn't handling any key events,
+   *                              always returns FALSE.
+   */
+  bool KeyPressWasHandled() {
+    KeyEventState* currentKeyEvent = GetCurrentKeyEvent();
+    return currentKeyEvent && currentKeyEvent->mKeyPressHandled;
+  }
+
+ protected:
+  // Stores the association of device dependent modifier flags with a modifier
+  // keyCode.  Being device dependent, this association may differ from one kind
+  // of hardware to the next.
+  struct ModifierKey {
+    NSUInteger flags;
+    unsigned short keyCode;
+
+    ModifierKey(NSUInteger aFlags, unsigned short aKeyCode)
+        : flags(aFlags), keyCode(aKeyCode) {}
+
+    NSUInteger GetDeviceDependentFlags() const {
+      return (flags & ~NSEventModifierFlagDeviceIndependentFlagsMask);
+    }
+
+    NSUInteger GetDeviceIndependentFlags() const {
+      return (flags & NSEventModifierFlagDeviceIndependentFlagsMask);
+    }
+  };
+  typedef nsTArray<ModifierKey> ModifierKeyArray;
+  ModifierKeyArray mModifierKeys;
+
+  /**
+   * GetModifierKeyForNativeKeyCode() returns the stored ModifierKey for
+   * the key.
+   */
+  const ModifierKey* GetModifierKeyForNativeKeyCode(
+      unsigned short aKeyCode) const;
+
+  /**
+   * GetModifierKeyForDeviceDependentFlags() returns the stored ModifierKey for
+   * the device dependent flags.
+   */
+  const ModifierKey* GetModifierKeyForDeviceDependentFlags(
+      NSUInteger aFlags) const;
+
+  /**
+   * DispatchKeyEventForFlagsChanged() dispatches keydown event or keyup event
+   * for the aNativeEvent.
+   *
+   * @param aNativeEvent          A native flagschanged event which you want to
+   *                              dispatch our key event for.
+   * @param aDispatchKeyDown      TRUE if you want to dispatch a keydown event.
+   *                              Otherwise, i.e., to dispatch keyup event,
+   *                              FALSE.
+   */
+  void DispatchKeyEventForFlagsChanged(NSEvent* aNativeEvent,
+                                       bool aDispatchKeyDown);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // TextInputHandler_h_
diff --git a/widget/cocoa/TextInputHandler.mm b/widget/cocoa/TextInputHandler.mm
new file mode 100644
index 0000000000..1d96a3ce82
--- /dev/null
+++ b/widget/cocoa/TextInputHandler.mm
@@ -0,0 +1,5389 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 sw=2 et tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TextInputHandler.h"
+
+#include "mozilla/Logging.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/StaticPrefs_intl.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/ToString.h"
+
+#include "nsChildView.h"
+#include "nsObjCExceptions.h"
+#include "nsBidiUtils.h"
+#include "nsToolkit.h"
+#include "nsCocoaUtils.h"
+#include "WidgetUtils.h"
+#include "nsPrintfCString.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+// For collecting other people's log, tell them `MOZ_LOG=IMEHandler:4,sync`
+// rather than `MOZ_LOG=IMEHandler:5,sync` since using `5` may create too
+// big file.
+// Therefore you shouldn't use `LogLevel::Verbose` for logging usual behavior.
+mozilla::LazyLogModule gIMELog("IMEHandler");
+
+// For collecting other people's log, tell them `MOZ_LOG=KeyboardHandler:4,sync`
+// rather than `MOZ_LOG=KeyboardHandler:5,sync` since using `5` may create too
+// big file.
+// Therefore you shouldn't use `LogLevel::Verbose` for logging usual behavior.
+mozilla::LazyLogModule gKeyLog("KeyboardHandler");
+
+// The behavior of `TextInputHandler` class is important both for logging
+// keyboard handler and IME handler.  Therefore, the behavior is logged when
+// either `IMEHandler` or `KeyboardHandler` is set to `MOZ_LOG`.  Therefore,
+// you may not need to tell people
+// `MOZ_LOG=IMEHandler:4,KeyboardHandler:4,sync`.
+#define MOZ_LOG_KEY_OR_IME(aLogLevel, aArgs)                               \
+  MOZ_LOG(MOZ_LOG_TEST(gIMELog, aLogLevel) ? gIMELog : gKeyLog, aLogLevel, \
+          aArgs)
+
+static const char* OnOrOff(bool aBool) { return aBool ? "ON" : "off"; }
+
+static const char* TrueOrFalse(bool aBool) { return aBool ? "TRUE" : "FALSE"; }
+
+static const char* GetKeyNameForNativeKeyCode(unsigned short aNativeKeyCode) {
+  switch (aNativeKeyCode) {
+    case kVK_Escape:
+      return "Escape";
+    case kVK_RightCommand:
+      return "Right-Command";
+    case kVK_Command:
+      return "Command";
+    case kVK_Shift:
+      return "Shift";
+    case kVK_CapsLock:
+      return "CapsLock";
+    case kVK_Option:
+      return "Option";
+    case kVK_Control:
+      return "Control";
+    case kVK_RightShift:
+      return "Right-Shift";
+    case kVK_RightOption:
+      return "Right-Option";
+    case kVK_RightControl:
+      return "Right-Control";
+    case kVK_ANSI_KeypadClear:
+      return "Clear";
+
+    case kVK_F1:
+      return "F1";
+    case kVK_F2:
+      return "F2";
+    case kVK_F3:
+      return "F3";
+    case kVK_F4:
+      return "F4";
+    case kVK_F5:
+      return "F5";
+    case kVK_F6:
+      return "F6";
+    case kVK_F7:
+      return "F7";
+    case kVK_F8:
+      return "F8";
+    case kVK_F9:
+      return "F9";
+    case kVK_F10:
+      return "F10";
+    case kVK_F11:
+      return "F11";
+    case kVK_F12:
+      return "F12";
+    case kVK_F13:
+      return "F13/PrintScreen";
+    case kVK_F14:
+      return "F14/ScrollLock";
+    case kVK_F15:
+      return "F15/Pause";
+
+    case kVK_ANSI_Keypad0:
+      return "NumPad-0";
+    case kVK_ANSI_Keypad1:
+      return "NumPad-1";
+    case kVK_ANSI_Keypad2:
+      return "NumPad-2";
+    case kVK_ANSI_Keypad3:
+      return "NumPad-3";
+    case kVK_ANSI_Keypad4:
+      return "NumPad-4";
+    case kVK_ANSI_Keypad5:
+      return "NumPad-5";
+    case kVK_ANSI_Keypad6:
+      return "NumPad-6";
+    case kVK_ANSI_Keypad7:
+      return "NumPad-7";
+    case kVK_ANSI_Keypad8:
+      return "NumPad-8";
+    case kVK_ANSI_Keypad9:
+      return "NumPad-9";
+
+    case kVK_ANSI_KeypadMultiply:
+      return "NumPad-*";
+    case kVK_ANSI_KeypadPlus:
+      return "NumPad-+";
+    case kVK_ANSI_KeypadMinus:
+      return "NumPad--";
+    case kVK_ANSI_KeypadDecimal:
+      return "NumPad-.";
+    case kVK_ANSI_KeypadDivide:
+      return "NumPad-/";
+    case kVK_ANSI_KeypadEquals:
+      return "NumPad-=";
+    case kVK_ANSI_KeypadEnter:
+      return "NumPad-Enter";
+    case kVK_Return:
+      return "Return";
+    case kVK_Powerbook_KeypadEnter:
+      return "NumPad-EnterOnPowerBook";
+
+    case kVK_PC_Insert:
+      return "Insert/Help";
+    case kVK_PC_Delete:
+      return "Delete";
+    case kVK_Tab:
+      return "Tab";
+    case kVK_PC_Backspace:
+      return "Backspace";
+    case kVK_Home:
+      return "Home";
+    case kVK_End:
+      return "End";
+    case kVK_PageUp:
+      return "PageUp";
+    case kVK_PageDown:
+      return "PageDown";
+    case kVK_LeftArrow:
+      return "LeftArrow";
+    case kVK_RightArrow:
+      return "RightArrow";
+    case kVK_UpArrow:
+      return "UpArrow";
+    case kVK_DownArrow:
+      return "DownArrow";
+    case kVK_PC_ContextMenu:
+      return "ContextMenu";
+
+    case kVK_Function:
+      return "Function";
+    case kVK_VolumeUp:
+      return "VolumeUp";
+    case kVK_VolumeDown:
+      return "VolumeDown";
+    case kVK_Mute:
+      return "Mute";
+
+    case kVK_ISO_Section:
+      return "ISO_Section";
+
+    case kVK_JIS_Yen:
+      return "JIS_Yen";
+    case kVK_JIS_Underscore:
+      return "JIS_Underscore";
+    case kVK_JIS_KeypadComma:
+      return "JIS_KeypadComma";
+    case kVK_JIS_Eisu:
+      return "JIS_Eisu";
+    case kVK_JIS_Kana:
+      return "JIS_Kana";
+
+    case kVK_ANSI_A:
+      return "A";
+    case kVK_ANSI_B:
+      return "B";
+    case kVK_ANSI_C:
+      return "C";
+    case kVK_ANSI_D:
+      return "D";
+    case kVK_ANSI_E:
+      return "E";
+    case kVK_ANSI_F:
+      return "F";
+    case kVK_ANSI_G:
+      return "G";
+    case kVK_ANSI_H:
+      return "H";
+    case kVK_ANSI_I:
+      return "I";
+    case kVK_ANSI_J:
+      return "J";
+    case kVK_ANSI_K:
+      return "K";
+    case kVK_ANSI_L:
+      return "L";
+    case kVK_ANSI_M:
+      return "M";
+    case kVK_ANSI_N:
+      return "N";
+    case kVK_ANSI_O:
+      return "O";
+    case kVK_ANSI_P:
+      return "P";
+    case kVK_ANSI_Q:
+      return "Q";
+    case kVK_ANSI_R:
+      return "R";
+    case kVK_ANSI_S:
+      return "S";
+    case kVK_ANSI_T:
+      return "T";
+    case kVK_ANSI_U:
+      return "U";
+    case kVK_ANSI_V:
+      return "V";
+    case kVK_ANSI_W:
+      return "W";
+    case kVK_ANSI_X:
+      return "X";
+    case kVK_ANSI_Y:
+      return "Y";
+    case kVK_ANSI_Z:
+      return "Z";
+
+    case kVK_ANSI_1:
+      return "1";
+    case kVK_ANSI_2:
+      return "2";
+    case kVK_ANSI_3:
+      return "3";
+    case kVK_ANSI_4:
+      return "4";
+    case kVK_ANSI_5:
+      return "5";
+    case kVK_ANSI_6:
+      return "6";
+    case kVK_ANSI_7:
+      return "7";
+    case kVK_ANSI_8:
+      return "8";
+    case kVK_ANSI_9:
+      return "9";
+    case kVK_ANSI_0:
+      return "0";
+    case kVK_ANSI_Equal:
+      return "Equal";
+    case kVK_ANSI_Minus:
+      return "Minus";
+    case kVK_ANSI_RightBracket:
+      return "RightBracket";
+    case kVK_ANSI_LeftBracket:
+      return "LeftBracket";
+    case kVK_ANSI_Quote:
+      return "Quote";
+    case kVK_ANSI_Semicolon:
+      return "Semicolon";
+    case kVK_ANSI_Backslash:
+      return "Backslash";
+    case kVK_ANSI_Comma:
+      return "Comma";
+    case kVK_ANSI_Slash:
+      return "Slash";
+    case kVK_ANSI_Period:
+      return "Period";
+    case kVK_ANSI_Grave:
+      return "Grave";
+
+    default:
+      return "undefined";
+  }
+}
+
+static const char* GetCharacters(const nsAString& aString) {
+  if (aString.IsEmpty()) {
+    return "";
+  }
+  nsAutoString escapedStr;
+  for (uint32_t i = 0; i < aString.Length(); i++) {
+    char16_t ch = aString.CharAt(i);
+    if (ch < 0x20) {
+      nsPrintfCString utf8str("(U+%04X)", ch);
+      escapedStr += NS_ConvertUTF8toUTF16(utf8str);
+    } else if (ch <= 0x7E) {
+      escapedStr += ch;
+    } else {
+      nsPrintfCString utf8str("(U+%04X)", ch);
+      escapedStr += ch;
+      escapedStr += NS_ConvertUTF8toUTF16(utf8str);
+    }
+  }
+
+  // the result will be freed automatically by cocoa.
+  NSString* result = nsCocoaUtils::ToNSString(escapedStr);
+  return [result UTF8String];
+}
+
+static const char* GetCharacters(const NSString* aString) {
+  nsAutoString str;
+  nsCocoaUtils::GetStringForNSString(aString, str);
+  return GetCharacters(str);
+}
+
+static const char* GetCharacters(const CFStringRef aString) {
+  const NSString* str = reinterpret_cast<const NSString*>(aString);
+  return GetCharacters(str);
+}
+
+static const char* GetNativeKeyEventType(NSEvent* aNativeEvent) {
+  switch ([aNativeEvent type]) {
+    case NSEventTypeKeyDown:
+      return "NSEventTypeKeyDown";
+    case NSEventTypeKeyUp:
+      return "NSEventTypeKeyUp";
+    case NSEventTypeFlagsChanged:
+      return "NSEventTypeFlagsChanged";
+    default:
+      return "not key event";
+  }
+}
+
+static const char* GetGeckoKeyEventType(const WidgetEvent& aEvent) {
+  switch (aEvent.mMessage) {
+    case eKeyDown:
+      return "eKeyDown";
+    case eKeyUp:
+      return "eKeyUp";
+    case eKeyPress:
+      return "eKeyPress";
+    default:
+      return "not key event";
+  }
+}
+
+static const char* GetWindowLevelName(NSInteger aWindowLevel) {
+  switch (aWindowLevel) {
+    case kCGBaseWindowLevelKey:
+      return "kCGBaseWindowLevelKey (NSNormalWindowLevel)";
+    case kCGMinimumWindowLevelKey:
+      return "kCGMinimumWindowLevelKey";
+    case kCGDesktopWindowLevelKey:
+      return "kCGDesktopWindowLevelKey";
+    case kCGBackstopMenuLevelKey:
+      return "kCGBackstopMenuLevelKey";
+    case kCGNormalWindowLevelKey:
+      return "kCGNormalWindowLevelKey";
+    case kCGFloatingWindowLevelKey:
+      return "kCGFloatingWindowLevelKey (NSFloatingWindowLevel)";
+    case kCGTornOffMenuWindowLevelKey:
+      return "kCGTornOffMenuWindowLevelKey (NSSubmenuWindowLevel, "
+             "NSTornOffMenuWindowLevel)";
+    case kCGDockWindowLevelKey:
+      return "kCGDockWindowLevelKey (NSDockWindowLevel)";
+    case kCGMainMenuWindowLevelKey:
+      return "kCGMainMenuWindowLevelKey (NSMainMenuWindowLevel)";
+    case kCGStatusWindowLevelKey:
+      return "kCGStatusWindowLevelKey (NSStatusWindowLevel)";
+    case kCGModalPanelWindowLevelKey:
+      return "kCGModalPanelWindowLevelKey (NSModalPanelWindowLevel)";
+    case kCGPopUpMenuWindowLevelKey:
+      return "kCGPopUpMenuWindowLevelKey (NSPopUpMenuWindowLevel)";
+    case kCGDraggingWindowLevelKey:
+      return "kCGDraggingWindowLevelKey";
+    case kCGScreenSaverWindowLevelKey:
+      return "kCGScreenSaverWindowLevelKey (NSScreenSaverWindowLevel)";
+    case kCGMaximumWindowLevelKey:
+      return "kCGMaximumWindowLevelKey";
+    case kCGOverlayWindowLevelKey:
+      return "kCGOverlayWindowLevelKey";
+    case kCGHelpWindowLevelKey:
+      return "kCGHelpWindowLevelKey";
+    case kCGUtilityWindowLevelKey:
+      return "kCGUtilityWindowLevelKey";
+    case kCGDesktopIconWindowLevelKey:
+      return "kCGDesktopIconWindowLevelKey";
+    case kCGCursorWindowLevelKey:
+      return "kCGCursorWindowLevelKey";
+    case kCGNumberOfWindowLevelKeys:
+      return "kCGNumberOfWindowLevelKeys";
+    default:
+      return "unknown window level";
+  }
+}
+
+static bool IsControlChar(uint32_t aCharCode) {
+  return aCharCode < ' ' || aCharCode == 0x7F;
+}
+
+static uint32_t gHandlerInstanceCount = 0;
+
+static void EnsureToLogAllKeyboardLayoutsAndIMEs() {
+  static bool sDone = false;
+  if (!sDone) {
+    sDone = true;
+    TextInputHandler::DebugPrintAllKeyboardLayouts();
+    IMEInputHandler::DebugPrintAllIMEModes();
+  }
+}
+
+inline NSRange MakeNSRangeFrom(
+    const Maybe<OffsetAndData<uint32_t>>& aOffsetAndData) {
+  if (aOffsetAndData.isNothing()) {
+    return NSMakeRange(NSNotFound, 0);
+  }
+  return NSMakeRange(aOffsetAndData->StartOffset(), aOffsetAndData->Length());
+}
+
+#pragma mark -
+
+/******************************************************************************
+ *
+ *  TISInputSourceWrapper implementation
+ *
+ ******************************************************************************/
+
+TISInputSourceWrapper* TISInputSourceWrapper::sCurrentInputSource = nullptr;
+
+// static
+TISInputSourceWrapper& TISInputSourceWrapper::CurrentInputSource() {
+  if (!sCurrentInputSource) {
+    sCurrentInputSource = new TISInputSourceWrapper();
+  }
+  if (!sCurrentInputSource->IsInitializedByCurrentInputSource()) {
+    sCurrentInputSource->InitByCurrentInputSource();
+  }
+  return *sCurrentInputSource;
+}
+
+// static
+void TISInputSourceWrapper::Shutdown() {
+  if (!sCurrentInputSource) {
+    return;
+  }
+  sCurrentInputSource->Clear();
+  delete sCurrentInputSource;
+  sCurrentInputSource = nullptr;
+}
+
+bool TISInputSourceWrapper::TranslateToString(UInt32 aKeyCode,
+                                              UInt32 aModifiers, UInt32 aKbType,
+                                              nsAString& aStr) {
+  aStr.Truncate();
+
+  const UCKeyboardLayout* UCKey = GetUCKeyboardLayout();
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p TISInputSourceWrapper::TranslateToString, aKeyCode=0x%X, "
+           "aModifiers=0x%X, aKbType=0x%X UCKey=%p\n    "
+           "Shift: %s, Ctrl: %s, Opt: %s, Cmd: %s, CapsLock: %s, NumLock: %s",
+           this, static_cast<unsigned int>(aKeyCode),
+           static_cast<unsigned int>(aModifiers),
+           static_cast<unsigned int>(aKbType), UCKey,
+           OnOrOff(aModifiers & shiftKey), OnOrOff(aModifiers & controlKey),
+           OnOrOff(aModifiers & optionKey), OnOrOff(aModifiers & cmdKey),
+           OnOrOff(aModifiers & alphaLock),
+           OnOrOff(aModifiers & kEventKeyModifierNumLockMask)));
+
+  NS_ENSURE_TRUE(UCKey, false);
+
+  UInt32 deadKeyState = 0;
+  UniCharCount len;
+  UniChar chars[5];
+  OSStatus err = ::UCKeyTranslate(
+      UCKey, aKeyCode, kUCKeyActionDown, aModifiers >> 8, aKbType,
+      kUCKeyTranslateNoDeadKeysMask, &deadKeyState, 5, &len, chars);
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   TISInputSourceWrapper::TranslateToString, err=0x%X, len=%zu",
+           this, static_cast<int>(err), len));
+
+  NS_ENSURE_TRUE(err == noErr, false);
+  if (len == 0) {
+    return true;
+  }
+  if (!aStr.SetLength(len, fallible)) {
+    return false;
+  }
+  NS_ASSERTION(sizeof(char16_t) == sizeof(UniChar),
+               "size of char16_t and size of UniChar are different");
+  memcpy(aStr.BeginWriting(), chars, len * sizeof(char16_t));
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   TISInputSourceWrapper::TranslateToString, aStr=\"%s\"", this,
+           NS_ConvertUTF16toUTF8(aStr).get()));
+
+  return true;
+}
+
+uint32_t TISInputSourceWrapper::TranslateToChar(UInt32 aKeyCode,
+                                                UInt32 aModifiers,
+                                                UInt32 aKbType) {
+  nsAutoString str;
+  if (!TranslateToString(aKeyCode, aModifiers, aKbType, str) ||
+      str.Length() != 1) {
+    return 0;
+  }
+  return static_cast<uint32_t>(str.CharAt(0));
+}
+
+bool TISInputSourceWrapper::IsDeadKey(NSEvent* aNativeKeyEvent) {
+  if ([[aNativeKeyEvent characters] length]) {
+    return false;
+  }
+
+  // Assmue that if control key or command key is pressed, it's not a dead key.
+  NSUInteger cocoaState = [aNativeKeyEvent modifierFlags];
+  if (cocoaState & (NSEventModifierFlagControl | NSEventModifierFlagCommand)) {
+    return false;
+  }
+
+  UInt32 nativeKeyCode = [aNativeKeyEvent keyCode];
+  switch (nativeKeyCode) {
+    case kVK_ANSI_A:
+    case kVK_ANSI_B:
+    case kVK_ANSI_C:
+    case kVK_ANSI_D:
+    case kVK_ANSI_E:
+    case kVK_ANSI_F:
+    case kVK_ANSI_G:
+    case kVK_ANSI_H:
+    case kVK_ANSI_I:
+    case kVK_ANSI_J:
+    case kVK_ANSI_K:
+    case kVK_ANSI_L:
+    case kVK_ANSI_M:
+    case kVK_ANSI_N:
+    case kVK_ANSI_O:
+    case kVK_ANSI_P:
+    case kVK_ANSI_Q:
+    case kVK_ANSI_R:
+    case kVK_ANSI_S:
+    case kVK_ANSI_T:
+    case kVK_ANSI_U:
+    case kVK_ANSI_V:
+    case kVK_ANSI_W:
+    case kVK_ANSI_X:
+    case kVK_ANSI_Y:
+    case kVK_ANSI_Z:
+    case kVK_ANSI_1:
+    case kVK_ANSI_2:
+    case kVK_ANSI_3:
+    case kVK_ANSI_4:
+    case kVK_ANSI_5:
+    case kVK_ANSI_6:
+    case kVK_ANSI_7:
+    case kVK_ANSI_8:
+    case kVK_ANSI_9:
+    case kVK_ANSI_0:
+    case kVK_ANSI_Equal:
+    case kVK_ANSI_Minus:
+    case kVK_ANSI_RightBracket:
+    case kVK_ANSI_LeftBracket:
+    case kVK_ANSI_Quote:
+    case kVK_ANSI_Semicolon:
+    case kVK_ANSI_Backslash:
+    case kVK_ANSI_Comma:
+    case kVK_ANSI_Slash:
+    case kVK_ANSI_Period:
+    case kVK_ANSI_Grave:
+    case kVK_JIS_Yen:
+    case kVK_JIS_Underscore:
+      break;
+    default:
+      // Let's assume that dead key can be only a printable key in standard
+      // position.
+      return false;
+  }
+
+  // If TranslateToChar() returns non-zero value, that means that
+  // the key may input a character with different dead key state.
+  UInt32 kbType = GetKbdType();
+  UInt32 carbonState = nsCocoaUtils::ConvertToCarbonModifier(cocoaState);
+  return IsDeadKey(nativeKeyCode, carbonState, kbType);
+}
+
+bool TISInputSourceWrapper::IsDeadKey(UInt32 aKeyCode, UInt32 aModifiers,
+                                      UInt32 aKbType) {
+  const UCKeyboardLayout* UCKey = GetUCKeyboardLayout();
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p TISInputSourceWrapper::IsDeadKey, aKeyCode=0x%X, "
+           "aModifiers=0x%X, aKbType=0x%X UCKey=%p\n    "
+           "Shift: %s, Ctrl: %s, Opt: %s, Cmd: %s, CapsLock: %s, NumLock: %s",
+           this, static_cast<unsigned int>(aKeyCode),
+           static_cast<unsigned int>(aModifiers),
+           static_cast<unsigned int>(aKbType), UCKey,
+           OnOrOff(aModifiers & shiftKey), OnOrOff(aModifiers & controlKey),
+           OnOrOff(aModifiers & optionKey), OnOrOff(aModifiers & cmdKey),
+           OnOrOff(aModifiers & alphaLock),
+           OnOrOff(aModifiers & kEventKeyModifierNumLockMask)));
+
+  if (NS_WARN_IF(!UCKey)) {
+    return false;
+  }
+
+  UInt32 deadKeyState = 0;
+  UniCharCount len;
+  UniChar chars[5];
+  OSStatus err =
+      ::UCKeyTranslate(UCKey, aKeyCode, kUCKeyActionDown, aModifiers >> 8,
+                       aKbType, 0, &deadKeyState, 5, &len, chars);
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   TISInputSourceWrapper::IsDeadKey, err=0x%X, "
+           "len=%zu, deadKeyState=%u",
+           this, static_cast<int>(err), len, deadKeyState));
+
+  if (NS_WARN_IF(err != noErr)) {
+    return false;
+  }
+
+  return deadKeyState != 0;
+}
+
+void TISInputSourceWrapper::InitByInputSourceID(const char* aID) {
+  Clear();
+  if (!aID) return;
+
+  CFStringRef idstr = ::CFStringCreateWithCString(kCFAllocatorDefault, aID,
+                                                  kCFStringEncodingASCII);
+  InitByInputSourceID(idstr);
+  ::CFRelease(idstr);
+}
+
+void TISInputSourceWrapper::InitByInputSourceID(const nsString& aID) {
+  Clear();
+  if (aID.IsEmpty()) return;
+  CFStringRef idstr = ::CFStringCreateWithCharacters(
+      kCFAllocatorDefault, reinterpret_cast<const UniChar*>(aID.get()),
+      aID.Length());
+  InitByInputSourceID(idstr);
+  ::CFRelease(idstr);
+}
+
+void TISInputSourceWrapper::InitByInputSourceID(const CFStringRef aID) {
+  Clear();
+  if (!aID) return;
+  const void* keys[] = {kTISPropertyInputSourceID};
+  const void* values[] = {aID};
+  CFDictionaryRef filter =
+      ::CFDictionaryCreate(kCFAllocatorDefault, keys, values, 1, NULL, NULL);
+  NS_ASSERTION(filter, "failed to create the filter");
+  mInputSourceList = ::TISCreateInputSourceList(filter, true);
+  ::CFRelease(filter);
+  if (::CFArrayGetCount(mInputSourceList) > 0) {
+    mInputSource = static_cast<TISInputSourceRef>(
+        const_cast<void*>(::CFArrayGetValueAtIndex(mInputSourceList, 0)));
+    if (IsKeyboardLayout()) {
+      mKeyboardLayout = mInputSource;
+    }
+  }
+}
+
+void TISInputSourceWrapper::InitByLayoutID(SInt32 aLayoutID,
+                                           bool aOverrideKeyboard) {
+  // NOTE: Doument new layout IDs in TextInputHandler.h when you add ones.
+  switch (aLayoutID) {
+    case 0:
+      InitByInputSourceID("com.apple.keylayout.US");
+      break;
+    case 1:
+      InitByInputSourceID("com.apple.keylayout.Greek");
+      break;
+    case 2:
+      InitByInputSourceID("com.apple.keylayout.German");
+      break;
+    case 3:
+      InitByInputSourceID("com.apple.keylayout.Swedish-Pro");
+      break;
+    case 4:
+      InitByInputSourceID("com.apple.keylayout.DVORAK-QWERTYCMD");
+      break;
+    case 5:
+      InitByInputSourceID("com.apple.keylayout.Thai");
+      break;
+    case 6:
+      InitByInputSourceID("com.apple.keylayout.Arabic");
+      break;
+    case 7:
+      InitByInputSourceID("com.apple.keylayout.ArabicPC");
+      break;
+    case 8:
+      InitByInputSourceID("com.apple.keylayout.French");
+      break;
+    case 9:
+      InitByInputSourceID("com.apple.keylayout.Hebrew");
+      break;
+    case 10:
+      InitByInputSourceID("com.apple.keylayout.Lithuanian");
+      break;
+    case 11:
+      InitByInputSourceID("com.apple.keylayout.Norwegian");
+      break;
+    case 12:
+      InitByInputSourceID("com.apple.keylayout.Spanish");
+      break;
+    case 13:
+      InitByInputSourceID("com.apple.keylayout.French-PC");
+      break;
+    default:
+      Clear();
+      break;
+  }
+  mOverrideKeyboard = aOverrideKeyboard;
+}
+
+void TISInputSourceWrapper::InitByCurrentInputSource() {
+  Clear();
+  mInputSource = ::TISCopyCurrentKeyboardInputSource();
+  mKeyboardLayout = ::TISCopyInputMethodKeyboardLayoutOverride();
+  if (!mKeyboardLayout) {
+    mKeyboardLayout = ::TISCopyCurrentKeyboardLayoutInputSource();
+  }
+  // If this causes composition, the current keyboard layout may input non-ASCII
+  // characters such as Japanese Kana characters or Hangul characters.
+  // However, we need to set ASCII characters to DOM key events for consistency
+  // with other platforms.
+  if (IsOpenedIMEMode()) {
+    TISInputSourceWrapper tis(mKeyboardLayout);
+    if (!tis.IsASCIICapable()) {
+      mKeyboardLayout = ::TISCopyCurrentASCIICapableKeyboardLayoutInputSource();
+    }
+  }
+}
+
+void TISInputSourceWrapper::InitByCurrentKeyboardLayout() {
+  Clear();
+  mInputSource = ::TISCopyCurrentKeyboardLayoutInputSource();
+  mKeyboardLayout = mInputSource;
+}
+
+void TISInputSourceWrapper::InitByCurrentASCIICapableInputSource() {
+  Clear();
+  mInputSource = ::TISCopyCurrentASCIICapableKeyboardInputSource();
+  mKeyboardLayout = ::TISCopyInputMethodKeyboardLayoutOverride();
+  if (mKeyboardLayout) {
+    TISInputSourceWrapper tis(mKeyboardLayout);
+    if (!tis.IsASCIICapable()) {
+      mKeyboardLayout = nullptr;
+    }
+  }
+  if (!mKeyboardLayout) {
+    mKeyboardLayout = ::TISCopyCurrentASCIICapableKeyboardLayoutInputSource();
+  }
+}
+
+void TISInputSourceWrapper::InitByCurrentASCIICapableKeyboardLayout() {
+  Clear();
+  mInputSource = ::TISCopyCurrentASCIICapableKeyboardLayoutInputSource();
+  mKeyboardLayout = mInputSource;
+}
+
+void TISInputSourceWrapper::InitByCurrentInputMethodKeyboardLayoutOverride() {
+  Clear();
+  mInputSource = ::TISCopyInputMethodKeyboardLayoutOverride();
+  mKeyboardLayout = mInputSource;
+}
+
+void TISInputSourceWrapper::InitByTISInputSourceRef(
+    TISInputSourceRef aInputSource) {
+  Clear();
+  mInputSource = aInputSource;
+  if (IsKeyboardLayout()) {
+    mKeyboardLayout = mInputSource;
+  }
+}
+
+void TISInputSourceWrapper::InitByLanguage(CFStringRef aLanguage) {
+  Clear();
+  mInputSource = ::TISCopyInputSourceForLanguage(aLanguage);
+  if (IsKeyboardLayout()) {
+    mKeyboardLayout = mInputSource;
+  }
+}
+
+const UCKeyboardLayout* TISInputSourceWrapper::GetUCKeyboardLayout() {
+  NS_ENSURE_TRUE(mKeyboardLayout, nullptr);
+  if (mUCKeyboardLayout) {
+    return mUCKeyboardLayout;
+  }
+  CFDataRef uchr = static_cast<CFDataRef>(::TISGetInputSourceProperty(
+      mKeyboardLayout, kTISPropertyUnicodeKeyLayoutData));
+
+  // We should be always able to get the layout here.
+  NS_ENSURE_TRUE(uchr, nullptr);
+  mUCKeyboardLayout =
+      reinterpret_cast<const UCKeyboardLayout*>(CFDataGetBytePtr(uchr));
+  return mUCKeyboardLayout;
+}
+
+bool TISInputSourceWrapper::GetBoolProperty(const CFStringRef aKey) {
+  CFBooleanRef ret = static_cast<CFBooleanRef>(
+      ::TISGetInputSourceProperty(mInputSource, aKey));
+  return ::CFBooleanGetValue(ret);
+}
+
+bool TISInputSourceWrapper::GetStringProperty(const CFStringRef aKey,
+                                              CFStringRef& aStr) {
+  aStr =
+      static_cast<CFStringRef>(::TISGetInputSourceProperty(mInputSource, aKey));
+  return aStr != nullptr;
+}
+
+bool TISInputSourceWrapper::GetStringProperty(const CFStringRef aKey,
+                                              nsAString& aStr) {
+  CFStringRef str;
+  GetStringProperty(aKey, str);
+  nsCocoaUtils::GetStringForNSString((const NSString*)str, aStr);
+  return !aStr.IsEmpty();
+}
+
+bool TISInputSourceWrapper::IsOpenedIMEMode() {
+  NS_ENSURE_TRUE(mInputSource, false);
+  if (!IsIMEMode()) return false;
+  return !IsASCIICapable();
+}
+
+bool TISInputSourceWrapper::IsIMEMode() {
+  NS_ENSURE_TRUE(mInputSource, false);
+  CFStringRef str;
+  GetInputSourceType(str);
+  NS_ENSURE_TRUE(str, false);
+  return ::CFStringCompare(kTISTypeKeyboardInputMode, str, 0) ==
+         kCFCompareEqualTo;
+}
+
+bool TISInputSourceWrapper::IsKeyboardLayout() {
+  NS_ENSURE_TRUE(mInputSource, false);
+  CFStringRef str;
+  GetInputSourceType(str);
+  NS_ENSURE_TRUE(str, false);
+  return ::CFStringCompare(kTISTypeKeyboardLayout, str, 0) == kCFCompareEqualTo;
+}
+
+bool TISInputSourceWrapper::GetLanguageList(CFArrayRef& aLanguageList) {
+  NS_ENSURE_TRUE(mInputSource, false);
+  aLanguageList = static_cast<CFArrayRef>(::TISGetInputSourceProperty(
+      mInputSource, kTISPropertyInputSourceLanguages));
+  return aLanguageList != nullptr;
+}
+
+bool TISInputSourceWrapper::GetPrimaryLanguage(CFStringRef& aPrimaryLanguage) {
+  NS_ENSURE_TRUE(mInputSource, false);
+  CFArrayRef langList;
+  NS_ENSURE_TRUE(GetLanguageList(langList), false);
+  if (::CFArrayGetCount(langList) == 0) return false;
+  aPrimaryLanguage =
+      static_cast<CFStringRef>(::CFArrayGetValueAtIndex(langList, 0));
+  return aPrimaryLanguage != nullptr;
+}
+
+bool TISInputSourceWrapper::GetPrimaryLanguage(nsAString& aPrimaryLanguage) {
+  NS_ENSURE_TRUE(mInputSource, false);
+  CFStringRef primaryLanguage;
+  NS_ENSURE_TRUE(GetPrimaryLanguage(primaryLanguage), false);
+  nsCocoaUtils::GetStringForNSString((const NSString*)primaryLanguage,
+                                     aPrimaryLanguage);
+  return !aPrimaryLanguage.IsEmpty();
+}
+
+bool TISInputSourceWrapper::IsForRTLLanguage() {
+  if (mIsRTL < 0) {
+    // Get the input character of the 'A' key of ANSI keyboard layout.
+    nsAutoString str;
+    bool ret = TranslateToString(kVK_ANSI_A, 0, eKbdType_ANSI, str);
+    NS_ENSURE_TRUE(ret, ret);
+    char16_t ch = str.IsEmpty() ? char16_t(0) : str.CharAt(0);
+    mIsRTL = UTF16_CODE_UNIT_IS_BIDI(ch);
+  }
+  return mIsRTL != 0;
+}
+
+bool TISInputSourceWrapper::IsForJapaneseLanguage() {
+  nsAutoString lang;
+  GetPrimaryLanguage(lang);
+  return lang.EqualsLiteral("ja");
+}
+
+bool TISInputSourceWrapper::IsInitializedByCurrentInputSource() {
+  return mInputSource == ::TISCopyCurrentKeyboardInputSource();
+}
+
+void TISInputSourceWrapper::Select() {
+  if (!mInputSource) return;
+  ::TISSelectInputSource(mInputSource);
+}
+
+void TISInputSourceWrapper::Clear() {
+  // Clear() is always called when TISInputSourceWrappper is created.
+  EnsureToLogAllKeyboardLayoutsAndIMEs();
+
+  if (mInputSourceList) {
+    ::CFRelease(mInputSourceList);
+  }
+  mInputSourceList = nullptr;
+  mInputSource = nullptr;
+  mKeyboardLayout = nullptr;
+  mIsRTL = -1;
+  mUCKeyboardLayout = nullptr;
+  mOverrideKeyboard = false;
+}
+
+bool TISInputSourceWrapper::IsPrintableKeyEvent(
+    NSEvent* aNativeKeyEvent) const {
+  UInt32 nativeKeyCode = [aNativeKeyEvent keyCode];
+
+  bool isPrintableKey = !TextInputHandler::IsSpecialGeckoKey(nativeKeyCode);
+  if (isPrintableKey && [aNativeKeyEvent type] != NSEventTypeKeyDown &&
+      [aNativeKeyEvent type] != NSEventTypeKeyUp) {
+    NS_WARNING("Why would a printable key not be an NSEventTypeKeyDown or "
+               "NSEventTypeKeyUp event?");
+    isPrintableKey = false;
+  }
+  return isPrintableKey;
+}
+
+UInt32 TISInputSourceWrapper::GetKbdType() const {
+  // If a keyboard layout override is set, we also need to force the keyboard
+  // type to something ANSI to avoid test failures on machines with JIS
+  // keyboards (since the pair of keyboard layout and physical keyboard type
+  // form the actual key layout).  This assumes that the test setting the
+  // override was written assuming an ANSI keyboard.
+  return mOverrideKeyboard ? eKbdType_ANSI : ::LMGetKbdType();
+}
+
+void TISInputSourceWrapper::ComputeInsertStringForCharCode(
+    NSEvent* aNativeKeyEvent, const WidgetKeyboardEvent& aKeyEvent,
+    const nsAString* aInsertString, nsAString& aResult) {
+  if (aInsertString) {
+    // If the caller expects that the aInsertString will be input, we shouldn't
+    // change it.
+    aResult = *aInsertString;
+  } else if (IsPrintableKeyEvent(aNativeKeyEvent)) {
+    // If IME is open, [aNativeKeyEvent characters] may be a character
+    // which will be appended to the composition string.  However, especially,
+    // while IME is disabled, most users and developers expect the key event
+    // works as IME closed.  So, we should compute the aResult with
+    // the ASCII capable keyboard layout.
+    // NOTE: Such keyboard layouts typically change the layout to its ASCII
+    //       capable layout when Command key is pressed.  And we don't worry
+    //       when Control key is pressed too because it causes inputting
+    //       control characters.
+    // Additionally, if the key event doesn't input any text, the event may be
+    // dead key event.  In this case, the charCode value should be the dead
+    // character.
+    UInt32 nativeKeyCode = [aNativeKeyEvent keyCode];
+    if ((!aKeyEvent.IsMeta() && !aKeyEvent.IsControl() && IsOpenedIMEMode()) ||
+        ![[aNativeKeyEvent characters] length]) {
+      UInt32 state = nsCocoaUtils::ConvertToCarbonModifier(
+          [aNativeKeyEvent modifierFlags]);
+      uint32_t ch = TranslateToChar(nativeKeyCode, state, GetKbdType());
+      if (ch) {
+        aResult = ch;
+      }
+    } else {
+      // If the caller isn't sure what string will be input, let's use
+      // characters of NSEvent.
+      nsCocoaUtils::GetStringForNSString([aNativeKeyEvent characters], aResult);
+    }
+
+    // If control key is pressed and the eventChars is a non-printable control
+    // character, we should convert it to ASCII alphabet.
+    if (aKeyEvent.IsControl() && !aResult.IsEmpty() &&
+        aResult[0] <= char16_t(26)) {
+      aResult = (aKeyEvent.IsShift() ^ aKeyEvent.IsCapsLocked())
+                    ? static_cast<char16_t>(aResult[0] + ('A' - 1))
+                    : static_cast<char16_t>(aResult[0] + ('a' - 1));
+    }
+    // If Meta key is pressed, it may cause to switch the keyboard layout like
+    // Arabic, Russian, Hebrew, Greek and Dvorak-QWERTY.
+    else if (aKeyEvent.IsMeta() &&
+             !(aKeyEvent.IsControl() || aKeyEvent.IsAlt())) {
+      UInt32 kbType = GetKbdType();
+      UInt32 numLockState =
+          aKeyEvent.IsNumLocked() ? kEventKeyModifierNumLockMask : 0;
+      UInt32 capsLockState = aKeyEvent.IsCapsLocked() ? alphaLock : 0;
+      UInt32 shiftState = aKeyEvent.IsShift() ? shiftKey : 0;
+      uint32_t uncmdedChar =
+          TranslateToChar(nativeKeyCode, numLockState, kbType);
+      uint32_t cmdedChar =
+          TranslateToChar(nativeKeyCode, cmdKey | numLockState, kbType);
+      // If we can make a good guess at the characters that the user would
+      // expect this key combination to produce (with and without Shift) then
+      // use those characters.  This also corrects for CapsLock.
+      uint32_t ch = 0;
+      if (uncmdedChar == cmdedChar) {
+        // The characters produced with Command seem similar to those without
+        // Command.
+        ch = TranslateToChar(nativeKeyCode,
+                             shiftState | capsLockState | numLockState, kbType);
+      } else {
+        TISInputSourceWrapper USLayout("com.apple.keylayout.US");
+        uint32_t uncmdedUSChar =
+            USLayout.TranslateToChar(nativeKeyCode, numLockState, kbType);
+        // If it looks like characters from US keyboard layout when Command key
+        // is pressed, we should compute a character in the layout.
+        if (uncmdedUSChar == cmdedChar) {
+          ch = USLayout.TranslateToChar(
+              nativeKeyCode, shiftState | capsLockState | numLockState, kbType);
+        }
+      }
+
+      // If there is a more preferred character for the commanded key event,
+      // we should use it.
+      if (ch) {
+        aResult = ch;
+      }
+    }
+  }
+
+  // Remove control characters which shouldn't be inputted on editor.
+  // XXX Currently, we don't find any cases inserting control characters with
+  //     printable character.  So, just checking first character is enough.
+  if (!aResult.IsEmpty() && IsControlChar(aResult[0])) {
+    aResult.Truncate();
+  }
+}
+
+void TISInputSourceWrapper::InitKeyEvent(NSEvent* aNativeKeyEvent,
+                                         WidgetKeyboardEvent& aKeyEvent,
+                                         bool aIsProcessedByIME,
+                                         const nsAString* aInsertString) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_ASSERT(!aIsProcessedByIME || aKeyEvent.mMessage != eKeyPress,
+             "eKeyPress event should not be marked as proccessed by IME");
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p TISInputSourceWrapper::InitKeyEvent, aNativeKeyEvent=%p, "
+           "aKeyEvent.mMessage=%s, aProcessedByIME=%s, aInsertString=%p, "
+           "IsOpenedIMEMode()=%s",
+           this, aNativeKeyEvent, GetGeckoKeyEventType(aKeyEvent),
+           TrueOrFalse(aIsProcessedByIME), aInsertString,
+           TrueOrFalse(IsOpenedIMEMode())));
+
+  if (NS_WARN_IF(!aNativeKeyEvent)) {
+    return;
+  }
+
+  nsCocoaUtils::InitInputEvent(aKeyEvent, aNativeKeyEvent);
+
+  // This is used only while dispatching the event (which is a synchronous
+  // call), so there is no need to retain and release this data.
+  aKeyEvent.mNativeKeyEvent = aNativeKeyEvent;
+
+  aKeyEvent.mRefPoint = LayoutDeviceIntPoint(0, 0);
+
+  UInt32 kbType = GetKbdType();
+  UInt32 nativeKeyCode = [aNativeKeyEvent keyCode];
+
+  // macOS handles dead key as IME.  If the key is first key press of dead
+  // key, we should use KEY_NAME_INDEX_Dead for first (dead) key event.
+  // So, if aIsProcessedByIME is true, it may be dead key.  Let's check
+  // if current key event is a dead key's keydown event.
+  bool isProcessedByIME =
+      aIsProcessedByIME &&
+      !TISInputSourceWrapper::CurrentInputSource().IsDeadKey(aNativeKeyEvent);
+
+  aKeyEvent.mKeyCode =
+      isProcessedByIME
+          ? NS_VK_PROCESSKEY
+          : ComputeGeckoKeyCode(nativeKeyCode, kbType, aKeyEvent.IsMeta());
+
+  switch (nativeKeyCode) {
+    case kVK_Command:
+    case kVK_Shift:
+    case kVK_Option:
+    case kVK_Control:
+      aKeyEvent.mLocation = eKeyLocationLeft;
+      break;
+
+    case kVK_RightCommand:
+    case kVK_RightShift:
+    case kVK_RightOption:
+    case kVK_RightControl:
+      aKeyEvent.mLocation = eKeyLocationRight;
+      break;
+
+    case kVK_ANSI_Keypad0:
+    case kVK_ANSI_Keypad1:
+    case kVK_ANSI_Keypad2:
+    case kVK_ANSI_Keypad3:
+    case kVK_ANSI_Keypad4:
+    case kVK_ANSI_Keypad5:
+    case kVK_ANSI_Keypad6:
+    case kVK_ANSI_Keypad7:
+    case kVK_ANSI_Keypad8:
+    case kVK_ANSI_Keypad9:
+    case kVK_ANSI_KeypadMultiply:
+    case kVK_ANSI_KeypadPlus:
+    case kVK_ANSI_KeypadMinus:
+    case kVK_ANSI_KeypadDecimal:
+    case kVK_ANSI_KeypadDivide:
+    case kVK_ANSI_KeypadEquals:
+    case kVK_ANSI_KeypadEnter:
+    case kVK_JIS_KeypadComma:
+    case kVK_Powerbook_KeypadEnter:
+      aKeyEvent.mLocation = eKeyLocationNumpad;
+      break;
+
+    default:
+      aKeyEvent.mLocation = eKeyLocationStandard;
+      break;
+  }
+
+  aKeyEvent.mIsRepeat = ([aNativeKeyEvent type] == NSEventTypeKeyDown)
+                            ? [aNativeKeyEvent isARepeat]
+                            : false;
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   TISInputSourceWrapper::InitKeyEvent, "
+           "shift=%s, ctrl=%s, alt=%s, meta=%s",
+           this, OnOrOff(aKeyEvent.IsShift()), OnOrOff(aKeyEvent.IsControl()),
+           OnOrOff(aKeyEvent.IsAlt()), OnOrOff(aKeyEvent.IsMeta())));
+
+  if (isProcessedByIME) {
+    aKeyEvent.mKeyNameIndex = KEY_NAME_INDEX_Process;
+  } else if (IsPrintableKeyEvent(aNativeKeyEvent)) {
+    aKeyEvent.mKeyNameIndex = KEY_NAME_INDEX_USE_STRING;
+    // If insertText calls this method, let's use the string.
+    if (aInsertString && !aInsertString->IsEmpty() &&
+        !IsControlChar((*aInsertString)[0])) {
+      aKeyEvent.mKeyValue = *aInsertString;
+    }
+    // If meta key is pressed, the printable key layout may be switched from
+    // non-ASCII capable layout to ASCII capable, or from Dvorak to QWERTY.
+    // KeyboardEvent.key value should be the switched layout's character.
+    else if (aKeyEvent.IsMeta()) {
+      nsCocoaUtils::GetStringForNSString([aNativeKeyEvent characters],
+                                         aKeyEvent.mKeyValue);
+    }
+    // If control key is pressed, some keys may produce printable character via
+    // [aNativeKeyEvent characters].  Otherwise, translate input character of
+    // the key without control key.
+    else if (aKeyEvent.IsControl()) {
+      NSUInteger cocoaState =
+          [aNativeKeyEvent modifierFlags] & ~NSEventModifierFlagControl;
+      UInt32 carbonState = nsCocoaUtils::ConvertToCarbonModifier(cocoaState);
+      if (IsDeadKey(nativeKeyCode, carbonState, kbType)) {
+        aKeyEvent.mKeyNameIndex = KEY_NAME_INDEX_Dead;
+      } else {
+        aKeyEvent.mKeyValue =
+            TranslateToChar(nativeKeyCode, carbonState, kbType);
+        if (!aKeyEvent.mKeyValue.IsEmpty() &&
+            IsControlChar(aKeyEvent.mKeyValue[0])) {
+          // Don't expose control character to the web.
+          aKeyEvent.mKeyValue.Truncate();
+        }
+      }
+    }
+    // Otherwise, KeyboardEvent.key expose
+    // [aNativeKeyEvent characters] value.  However, if IME is open and the
+    // keyboard layout isn't ASCII capable, exposing the non-ASCII character
+    // doesn't match with other platform's behavior.  For the compatibility
+    // with other platform's Gecko, we need to set a translated character.
+    else if (IsOpenedIMEMode()) {
+      UInt32 state = nsCocoaUtils::ConvertToCarbonModifier(
+          [aNativeKeyEvent modifierFlags]);
+      aKeyEvent.mKeyValue = TranslateToChar(nativeKeyCode, state, kbType);
+    } else {
+      nsCocoaUtils::GetStringForNSString([aNativeKeyEvent characters],
+                                         aKeyEvent.mKeyValue);
+      // If the key value is empty, the event may be a dead key event.
+      // If TranslateToChar() returns non-zero value, that means that
+      // the key may input a character with different dead key state.
+      if (aKeyEvent.mKeyValue.IsEmpty()) {
+        NSUInteger cocoaState = [aNativeKeyEvent modifierFlags];
+        UInt32 carbonState = nsCocoaUtils::ConvertToCarbonModifier(cocoaState);
+        if (TranslateToChar(nativeKeyCode, carbonState, kbType)) {
+          aKeyEvent.mKeyNameIndex = KEY_NAME_INDEX_Dead;
+        }
+      }
+    }
+
+    // Last resort.  If .key value becomes empty string, we should use
+    // charactersIgnoringModifiers, if it's available.
+    if (aKeyEvent.mKeyNameIndex == KEY_NAME_INDEX_USE_STRING &&
+        (aKeyEvent.mKeyValue.IsEmpty() ||
+         IsControlChar(aKeyEvent.mKeyValue[0]))) {
+      nsCocoaUtils::GetStringForNSString(
+          [aNativeKeyEvent charactersIgnoringModifiers], aKeyEvent.mKeyValue);
+      // But don't expose it if it's a control character.
+      if (!aKeyEvent.mKeyValue.IsEmpty() &&
+          IsControlChar(aKeyEvent.mKeyValue[0])) {
+        aKeyEvent.mKeyValue.Truncate();
+      }
+    }
+  } else {
+    // Compute the key for non-printable keys and some special printable keys.
+    aKeyEvent.mKeyNameIndex = ComputeGeckoKeyNameIndex(nativeKeyCode);
+  }
+
+  aKeyEvent.mCodeNameIndex = ComputeGeckoCodeNameIndex(nativeKeyCode, kbType);
+  MOZ_ASSERT(aKeyEvent.mCodeNameIndex != CODE_NAME_INDEX_USE_STRING);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK
+}
+
+void TISInputSourceWrapper::WillDispatchKeyboardEvent(
+    NSEvent* aNativeKeyEvent, const nsAString* aInsertString,
+    uint32_t aIndexOfKeypress, WidgetKeyboardEvent& aKeyEvent) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Nothing to do here if the native key event is neither NSEventTypeKeyDown
+  // nor NSEventTypeKeyUp because accessing [aNativeKeyEvent characters] causes
+  // throwing an exception.
+  if ([aNativeKeyEvent type] != NSEventTypeKeyDown &&
+      [aNativeKeyEvent type] != NSEventTypeKeyUp) {
+    return;
+  }
+
+  UInt32 kbType = GetKbdType();
+
+  if (MOZ_LOG_TEST(gKeyLog, LogLevel::Info)) {
+    nsAutoString chars;
+    nsCocoaUtils::GetStringForNSString([aNativeKeyEvent characters], chars);
+    NS_ConvertUTF16toUTF8 utf8Chars(chars);
+    char16_t uniChar = static_cast<char16_t>(aKeyEvent.mCharCode);
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p TISInputSourceWrapper::WillDispatchKeyboardEvent, "
+         "aNativeKeyEvent=%p, aInsertString=%p (\"%s\"), "
+         "aIndexOfKeypress=%u, [aNativeKeyEvent characters]=\"%s\", "
+         "aKeyEvent={ mMessage=%s, mCharCode=0x%X(%s) }, kbType=0x%X, "
+         "IsOpenedIMEMode()=%s",
+         this, aNativeKeyEvent, aInsertString,
+         aInsertString ? GetCharacters(*aInsertString) : "", aIndexOfKeypress,
+         GetCharacters([aNativeKeyEvent characters]),
+         GetGeckoKeyEventType(aKeyEvent), aKeyEvent.mCharCode,
+         uniChar ? NS_ConvertUTF16toUTF8(&uniChar, 1).get() : "",
+         static_cast<unsigned int>(kbType), TrueOrFalse(IsOpenedIMEMode())));
+  }
+
+  nsAutoString insertStringForCharCode;
+  ComputeInsertStringForCharCode(aNativeKeyEvent, aKeyEvent, aInsertString,
+                                 insertStringForCharCode);
+
+  // The mCharCode was set from mKeyValue. However, for example, when Ctrl key
+  // is pressed, its value should indicate an ASCII character for backward
+  // compatibility rather than inputting character without the modifiers.
+  // Therefore, we need to modify mCharCode value here.
+  uint32_t charCode = 0;
+  if (aIndexOfKeypress < insertStringForCharCode.Length()) {
+    charCode = insertStringForCharCode[aIndexOfKeypress];
+  }
+  aKeyEvent.SetCharCode(charCode);
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   TISInputSourceWrapper::WillDispatchKeyboardEvent, "
+           "aKeyEvent.mKeyCode=0x%X, aKeyEvent.mCharCode=0x%X",
+           this, aKeyEvent.mKeyCode, aKeyEvent.mCharCode));
+
+  // If aInsertString is not nullptr (it means InsertText() is called)
+  // and it acutally inputs a character, we don't need to append alternative
+  // charCode values since such keyboard event shouldn't be handled as
+  // a shortcut key.
+  if (aInsertString && charCode) {
+    return;
+  }
+
+  TISInputSourceWrapper USLayout("com.apple.keylayout.US");
+  bool isRomanKeyboardLayout = IsASCIICapable();
+
+  UInt32 key = [aNativeKeyEvent keyCode];
+
+  // Caps lock and num lock modifier state:
+  UInt32 lockState = 0;
+  if ([aNativeKeyEvent modifierFlags] & NSEventModifierFlagCapsLock) {
+    lockState |= alphaLock;
+  }
+  if ([aNativeKeyEvent modifierFlags] & NSEventModifierFlagNumericPad) {
+    lockState |= kEventKeyModifierNumLockMask;
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   TISInputSourceWrapper::WillDispatchKeyboardEvent, "
+           "isRomanKeyboardLayout=%s, kbType=0x%X, key=0x%X",
+           this, TrueOrFalse(isRomanKeyboardLayout),
+           static_cast<unsigned int>(kbType), static_cast<unsigned int>(key)));
+
+  nsString str;
+
+  // normal chars
+  uint32_t unshiftedChar = TranslateToChar(key, lockState, kbType);
+  UInt32 shiftLockMod = shiftKey | lockState;
+  uint32_t shiftedChar = TranslateToChar(key, shiftLockMod, kbType);
+
+  // characters generated with Cmd key
+  // XXX we should remove CapsLock state, which changes characters from
+  //     Latin to Cyrillic with Russian layout on 10.4 only when Cmd key
+  //     is pressed.
+  UInt32 numState = (lockState & ~alphaLock);  // only num lock state
+  uint32_t uncmdedChar = TranslateToChar(key, numState, kbType);
+  UInt32 shiftNumMod = numState | shiftKey;
+  uint32_t uncmdedShiftChar = TranslateToChar(key, shiftNumMod, kbType);
+  uint32_t uncmdedUSChar = USLayout.TranslateToChar(key, numState, kbType);
+  UInt32 cmdNumMod = cmdKey | numState;
+  uint32_t cmdedChar = TranslateToChar(key, cmdNumMod, kbType);
+  UInt32 cmdShiftNumMod = shiftKey | cmdNumMod;
+  uint32_t cmdedShiftChar = TranslateToChar(key, cmdShiftNumMod, kbType);
+
+  // Is the keyboard layout changed by Cmd key?
+  // E.g., Arabic, Russian, Hebrew, Greek and Dvorak-QWERTY.
+  bool isCmdSwitchLayout = uncmdedChar != cmdedChar;
+  // Is the keyboard layout for Latin, but Cmd key switches the layout?
+  // I.e., Dvorak-QWERTY
+  bool isDvorakQWERTY = isCmdSwitchLayout && isRomanKeyboardLayout;
+
+  // If the current keyboard is not Dvorak-QWERTY or Cmd is not pressed,
+  // we should append unshiftedChar and shiftedChar for handling the
+  // normal characters.  These are the characters that the user is most
+  // likely to associate with this key.
+  if ((unshiftedChar || shiftedChar) &&
+      (!aKeyEvent.IsMeta() || !isDvorakQWERTY)) {
+    AlternativeCharCode altCharCodes(unshiftedChar, shiftedChar);
+    aKeyEvent.mAlternativeCharCodes.AppendElement(altCharCodes);
+  }
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   TISInputSourceWrapper::WillDispatchKeyboardEvent, "
+           "aKeyEvent.isMeta=%s, isDvorakQWERTY=%s, "
+           "unshiftedChar=U+%X, shiftedChar=U+%X",
+           this, OnOrOff(aKeyEvent.IsMeta()), TrueOrFalse(isDvorakQWERTY),
+           unshiftedChar, shiftedChar));
+
+  // Most keyboard layouts provide the same characters in the NSEvents
+  // with Command+Shift as with Command.  However, with Command+Shift we
+  // want the character on the second level.  e.g. With a US QWERTY
+  // layout, we want "?" when the "/","?" key is pressed with
+  // Command+Shift.
+
+  // On a German layout, the OS gives us '/' with Cmd+Shift+SS(eszett)
+  // even though Cmd+SS is 'SS' and Shift+'SS' is '?'.  This '/' seems
+  // like a hack to make the Cmd+"?" event look the same as the Cmd+"?"
+  // event on a US keyboard.  The user thinks they are typing Cmd+"?", so
+  // we'll prefer the "?" character, replacing mCharCode with shiftedChar
+  // when Shift is pressed.  However, in case there is a layout where the
+  // character unique to Cmd+Shift is the character that the user expects,
+  // we'll send it as an alternative char.
+  bool hasCmdShiftOnlyChar =
+      cmdedChar != cmdedShiftChar && uncmdedShiftChar != cmdedShiftChar;
+  uint32_t originalCmdedShiftChar = cmdedShiftChar;
+
+  // If we can make a good guess at the characters that the user would
+  // expect this key combination to produce (with and without Shift) then
+  // use those characters.  This also corrects for CapsLock, which was
+  // ignored above.
+  if (!isCmdSwitchLayout) {
+    // The characters produced with Command seem similar to those without
+    // Command.
+    if (unshiftedChar) {
+      cmdedChar = unshiftedChar;
+    }
+    if (shiftedChar) {
+      cmdedShiftChar = shiftedChar;
+    }
+  } else if (uncmdedUSChar == cmdedChar) {
+    // It looks like characters from a US layout are provided when Command
+    // is down.
+    uint32_t ch = USLayout.TranslateToChar(key, lockState, kbType);
+    if (ch) {
+      cmdedChar = ch;
+    }
+    ch = USLayout.TranslateToChar(key, shiftLockMod, kbType);
+    if (ch) {
+      cmdedShiftChar = ch;
+    }
+  }
+
+  // If the current keyboard layout is switched by the Cmd key,
+  // we should append cmdedChar and shiftedCmdChar that are
+  // Latin char for the key.
+  // If the keyboard layout is Dvorak-QWERTY, we should append them only when
+  // command key is pressed because when command key isn't pressed, uncmded
+  // chars have been appended already.
+  if ((cmdedChar || cmdedShiftChar) && isCmdSwitchLayout &&
+      (aKeyEvent.IsMeta() || !isDvorakQWERTY)) {
+    AlternativeCharCode altCharCodes(cmdedChar, cmdedShiftChar);
+    aKeyEvent.mAlternativeCharCodes.AppendElement(altCharCodes);
+  }
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   TISInputSourceWrapper::WillDispatchKeyboardEvent, "
+           "hasCmdShiftOnlyChar=%s, isCmdSwitchLayout=%s, isDvorakQWERTY=%s, "
+           "cmdedChar=U+%X, cmdedShiftChar=U+%X",
+           this, TrueOrFalse(hasCmdShiftOnlyChar), TrueOrFalse(isDvorakQWERTY),
+           TrueOrFalse(isDvorakQWERTY), cmdedChar, cmdedShiftChar));
+  // Special case for 'SS' key of German layout. See the comment of
+  // hasCmdShiftOnlyChar definition for the detail.
+  if (hasCmdShiftOnlyChar && originalCmdedShiftChar) {
+    AlternativeCharCode altCharCodes(0, originalCmdedShiftChar);
+    aKeyEvent.mAlternativeCharCodes.AppendElement(altCharCodes);
+  }
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   TISInputSourceWrapper::WillDispatchKeyboardEvent, "
+           "hasCmdShiftOnlyChar=%s, originalCmdedShiftChar=U+%X",
+           this, TrueOrFalse(hasCmdShiftOnlyChar), originalCmdedShiftChar));
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK
+}
+
+uint32_t TISInputSourceWrapper::ComputeGeckoKeyCode(UInt32 aNativeKeyCode,
+                                                    UInt32 aKbType,
+                                                    bool aCmdIsPressed) {
+  MOZ_LOG(
+      gKeyLog, LogLevel::Info,
+      ("%p TISInputSourceWrapper::ComputeGeckoKeyCode, aNativeKeyCode=0x%X, "
+       "aKbType=0x%X, aCmdIsPressed=%s, IsOpenedIMEMode()=%s, "
+       "IsASCIICapable()=%s",
+       this, static_cast<unsigned int>(aNativeKeyCode),
+       static_cast<unsigned int>(aKbType), TrueOrFalse(aCmdIsPressed),
+       TrueOrFalse(IsOpenedIMEMode()), TrueOrFalse(IsASCIICapable())));
+
+  switch (aNativeKeyCode) {
+    case kVK_Space:
+      return NS_VK_SPACE;
+    case kVK_Escape:
+      return NS_VK_ESCAPE;
+
+    // modifiers
+    case kVK_RightCommand:
+    case kVK_Command:
+      return NS_VK_META;
+    case kVK_RightShift:
+    case kVK_Shift:
+      return NS_VK_SHIFT;
+    case kVK_CapsLock:
+      return NS_VK_CAPS_LOCK;
+    case kVK_RightControl:
+    case kVK_Control:
+      return NS_VK_CONTROL;
+    case kVK_RightOption:
+    case kVK_Option:
+      return NS_VK_ALT;
+
+    case kVK_ANSI_KeypadClear:
+      return NS_VK_CLEAR;
+
+    // function keys
+    case kVK_F1:
+      return NS_VK_F1;
+    case kVK_F2:
+      return NS_VK_F2;
+    case kVK_F3:
+      return NS_VK_F3;
+    case kVK_F4:
+      return NS_VK_F4;
+    case kVK_F5:
+      return NS_VK_F5;
+    case kVK_F6:
+      return NS_VK_F6;
+    case kVK_F7:
+      return NS_VK_F7;
+    case kVK_F8:
+      return NS_VK_F8;
+    case kVK_F9:
+      return NS_VK_F9;
+    case kVK_F10:
+      return NS_VK_F10;
+    case kVK_F11:
+      return NS_VK_F11;
+    case kVK_F12:
+      return NS_VK_F12;
+    // case kVK_F13:               return NS_VK_F13;  // clash with the 3 below
+    // case kVK_F14:               return NS_VK_F14;
+    // case kVK_F15:               return NS_VK_F15;
+    case kVK_F16:
+      return NS_VK_F16;
+    case kVK_F17:
+      return NS_VK_F17;
+    case kVK_F18:
+      return NS_VK_F18;
+    case kVK_F19:
+      return NS_VK_F19;
+
+    case kVK_PC_Pause:
+      return NS_VK_PAUSE;
+    case kVK_PC_ScrollLock:
+      return NS_VK_SCROLL_LOCK;
+    case kVK_PC_PrintScreen:
+      return NS_VK_PRINTSCREEN;
+
+    // keypad
+    case kVK_ANSI_Keypad0:
+      return NS_VK_NUMPAD0;
+    case kVK_ANSI_Keypad1:
+      return NS_VK_NUMPAD1;
+    case kVK_ANSI_Keypad2:
+      return NS_VK_NUMPAD2;
+    case kVK_ANSI_Keypad3:
+      return NS_VK_NUMPAD3;
+    case kVK_ANSI_Keypad4:
+      return NS_VK_NUMPAD4;
+    case kVK_ANSI_Keypad5:
+      return NS_VK_NUMPAD5;
+    case kVK_ANSI_Keypad6:
+      return NS_VK_NUMPAD6;
+    case kVK_ANSI_Keypad7:
+      return NS_VK_NUMPAD7;
+    case kVK_ANSI_Keypad8:
+      return NS_VK_NUMPAD8;
+    case kVK_ANSI_Keypad9:
+      return NS_VK_NUMPAD9;
+
+    case kVK_ANSI_KeypadMultiply:
+      return NS_VK_MULTIPLY;
+    case kVK_ANSI_KeypadPlus:
+      return NS_VK_ADD;
+    case kVK_ANSI_KeypadMinus:
+      return NS_VK_SUBTRACT;
+    case kVK_ANSI_KeypadDecimal:
+      return NS_VK_DECIMAL;
+    case kVK_ANSI_KeypadDivide:
+      return NS_VK_DIVIDE;
+
+    case kVK_JIS_KeypadComma:
+      return NS_VK_SEPARATOR;
+
+    // IME keys
+    case kVK_JIS_Eisu:
+      return NS_VK_EISU;
+    case kVK_JIS_Kana:
+      return NS_VK_KANA;
+
+    // these may clash with forward delete and help
+    case kVK_PC_Insert:
+      return NS_VK_INSERT;
+    case kVK_PC_Delete:
+      return NS_VK_DELETE;
+
+    case kVK_PC_Backspace:
+      return NS_VK_BACK;
+    case kVK_Tab:
+      return NS_VK_TAB;
+
+    case kVK_Home:
+      return NS_VK_HOME;
+    case kVK_End:
+      return NS_VK_END;
+
+    case kVK_PageUp:
+      return NS_VK_PAGE_UP;
+    case kVK_PageDown:
+      return NS_VK_PAGE_DOWN;
+
+    case kVK_LeftArrow:
+      return NS_VK_LEFT;
+    case kVK_RightArrow:
+      return NS_VK_RIGHT;
+    case kVK_UpArrow:
+      return NS_VK_UP;
+    case kVK_DownArrow:
+      return NS_VK_DOWN;
+
+    case kVK_PC_ContextMenu:
+      return NS_VK_CONTEXT_MENU;
+
+    case kVK_ANSI_1:
+      return NS_VK_1;
+    case kVK_ANSI_2:
+      return NS_VK_2;
+    case kVK_ANSI_3:
+      return NS_VK_3;
+    case kVK_ANSI_4:
+      return NS_VK_4;
+    case kVK_ANSI_5:
+      return NS_VK_5;
+    case kVK_ANSI_6:
+      return NS_VK_6;
+    case kVK_ANSI_7:
+      return NS_VK_7;
+    case kVK_ANSI_8:
+      return NS_VK_8;
+    case kVK_ANSI_9:
+      return NS_VK_9;
+    case kVK_ANSI_0:
+      return NS_VK_0;
+
+    case kVK_ANSI_KeypadEnter:
+    case kVK_Return:
+    case kVK_Powerbook_KeypadEnter:
+      return NS_VK_RETURN;
+  }
+
+  // If Cmd key is pressed, that causes switching keyboard layout temporarily.
+  // E.g., Dvorak-QWERTY.  Therefore, if Cmd key is pressed, we should honor it.
+  UInt32 modifiers = aCmdIsPressed ? cmdKey : 0;
+
+  uint32_t charCode = TranslateToChar(aNativeKeyCode, modifiers, aKbType);
+
+  // Special case for Mac.  Mac inputs Yen sign (U+00A5) directly instead of
+  // Back slash (U+005C).  We should return NS_VK_BACK_SLASH for compatibility
+  // with other platforms.
+  // XXX How about Won sign (U+20A9) which has same problem as Yen sign?
+  if (charCode == 0x00A5) {
+    return NS_VK_BACK_SLASH;
+  }
+
+  uint32_t keyCode = WidgetUtils::ComputeKeyCodeFromChar(charCode);
+  if (keyCode) {
+    return keyCode;
+  }
+
+  // If the unshifed char isn't an ASCII character, use shifted char.
+  charCode = TranslateToChar(aNativeKeyCode, modifiers | shiftKey, aKbType);
+  keyCode = WidgetUtils::ComputeKeyCodeFromChar(charCode);
+  if (keyCode) {
+    return keyCode;
+  }
+
+  if (!IsASCIICapable()) {
+    // Retry with ASCII capable keyboard layout.
+    TISInputSourceWrapper currentKeyboardLayout;
+    currentKeyboardLayout.InitByCurrentASCIICapableKeyboardLayout();
+    NS_ENSURE_TRUE(mInputSource != currentKeyboardLayout.mInputSource, 0);
+    keyCode = currentKeyboardLayout.ComputeGeckoKeyCode(aNativeKeyCode, aKbType,
+                                                        aCmdIsPressed);
+    // We've returned 0 for long time if keyCode isn't for an alphabet keys or
+    // a numeric key even in alternative ASCII capable keyboard layout because
+    // we decided that we should avoid setting same keyCode value to 2 or
+    // more keys since active keyboard layout may have a key to input the
+    // punctuation with different key.  However, setting keyCode to 0 makes
+    // some web applications which are aware of neither KeyboardEvent.key nor
+    // KeyboardEvent.code not work with Firefox when user selects non-ASCII
+    // capable keyboard layout such as Russian and Thai.  So, if alternative
+    // ASCII capable keyboard layout has keyCode value for the key, we should
+    // use it.  In other words, this behavior does that non-ASCII capable
+    // keyboard layout overrides some keys' keyCode value only if the key
+    // produces ASCII character by itself or with Shift key.
+    if (keyCode) {
+      return keyCode;
+    }
+  }
+
+  // Otherwise, let's decide keyCode value from the native virtual keycode
+  // value on major keyboard layout.
+  CodeNameIndex code = ComputeGeckoCodeNameIndex(aNativeKeyCode, aKbType);
+  return WidgetKeyboardEvent::GetFallbackKeyCodeOfPunctuationKey(code);
+}
+
+// static
+KeyNameIndex TISInputSourceWrapper::ComputeGeckoKeyNameIndex(
+    UInt32 aNativeKeyCode) {
+  // NOTE:
+  //   When unsupported keys like Convert, Nonconvert of Japanese keyboard is
+  //   pressed:
+  //     on 10.6.x, 'A' key event is fired (and also actually 'a' is inserted).
+  //     on 10.7.x, Nothing happens.
+  //     on 10.8.x, Nothing happens.
+  //     on 10.9.x, FlagsChanged event is fired with keyCode 0xFF.
+  switch (aNativeKeyCode) {
+#define NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, aKeyNameIndex) \
+  case aNativeKey:                                                     \
+    return aKeyNameIndex;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+
+    default:
+      return KEY_NAME_INDEX_Unidentified;
+  }
+}
+
+// static
+CodeNameIndex TISInputSourceWrapper::ComputeGeckoCodeNameIndex(
+    UInt32 aNativeKeyCode, UInt32 aKbType) {
+  // macOS swaps native key code between Backquote key and IntlBackslash key
+  // only when the keyboard type is ISO.  Let's treat the key code after
+  // swapping them here because Chromium does so only when computing .code
+  // value.
+  if (::KBGetLayoutType(aKbType) == kKeyboardISO) {
+    if (aNativeKeyCode == kVK_ISO_Section) {
+      aNativeKeyCode = kVK_ANSI_Grave;
+    } else if (aNativeKeyCode == kVK_ANSI_Grave) {
+      aNativeKeyCode = kVK_ISO_Section;
+    }
+  }
+
+  switch (aNativeKeyCode) {
+#define NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX(aNativeKey, aCodeNameIndex) \
+  case aNativeKey:                                                       \
+    return aCodeNameIndex;
+
+#include "NativeKeyToDOMCodeName.h"
+
+#undef NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX
+
+    default:
+      return CODE_NAME_INDEX_UNKNOWN;
+  }
+}
+
+#pragma mark -
+
+/******************************************************************************
+ *
+ *  TextInputHandler implementation (static methods)
+ *
+ ******************************************************************************/
+
+NSUInteger TextInputHandler::sLastModifierState = 0;
+
+// static
+CFArrayRef TextInputHandler::CreateAllKeyboardLayoutList() {
+  const void* keys[] = {kTISPropertyInputSourceType};
+  const void* values[] = {kTISTypeKeyboardLayout};
+  CFDictionaryRef filter =
+      ::CFDictionaryCreate(kCFAllocatorDefault, keys, values, 1, NULL, NULL);
+  NS_ASSERTION(filter, "failed to create the filter");
+  CFArrayRef list = ::TISCreateInputSourceList(filter, true);
+  ::CFRelease(filter);
+  return list;
+}
+
+// static
+void TextInputHandler::DebugPrintAllKeyboardLayouts() {
+  if (MOZ_LOG_TEST(gKeyLog, LogLevel::Info)) {
+    CFArrayRef list = CreateAllKeyboardLayoutList();
+    MOZ_LOG(gKeyLog, LogLevel::Info, ("Keyboard layout configuration:"));
+    CFIndex idx = ::CFArrayGetCount(list);
+    TISInputSourceWrapper tis;
+    for (CFIndex i = 0; i < idx; ++i) {
+      TISInputSourceRef inputSource = static_cast<TISInputSourceRef>(
+          const_cast<void*>(::CFArrayGetValueAtIndex(list, i)));
+      tis.InitByTISInputSourceRef(inputSource);
+      nsAutoString name, isid;
+      tis.GetLocalizedName(name);
+      tis.GetInputSourceID(isid);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  %s\t<%s>%s%s\n", NS_ConvertUTF16toUTF8(name).get(),
+               NS_ConvertUTF16toUTF8(isid).get(),
+               tis.IsASCIICapable() ? "" : "\t(Isn't ASCII capable)",
+               tis.IsKeyboardLayout() && tis.GetUCKeyboardLayout()
+                   ? ""
+                   : "\t(uchr is NOT AVAILABLE)"));
+    }
+    ::CFRelease(list);
+  }
+}
+
+#pragma mark -
+
+/******************************************************************************
+ *
+ *  TextInputHandler implementation
+ *
+ ******************************************************************************/
+
+TextInputHandler::TextInputHandler(nsChildView* aWidget,
+                                   NSView<mozView>* aNativeView)
+    : IMEInputHandler(aWidget, aNativeView) {
+  EnsureToLogAllKeyboardLayoutsAndIMEs();
+  [mView installTextInputHandler:this];
+}
+
+TextInputHandler::~TextInputHandler() { [mView uninstallTextInputHandler]; }
+
+bool TextInputHandler::HandleKeyDownEvent(NSEvent* aNativeEvent,
+                                          uint32_t aUniqueId) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (Destroyed()) {
+    MOZ_LOG_KEY_OR_IME(LogLevel::Info,
+                       ("%p TextInputHandler::HandleKeyDownEvent, "
+                        "widget has been already destroyed",
+                        this));
+    return false;
+  }
+
+  // Insert empty line to the log for easier to read.
+  MOZ_LOG_KEY_OR_IME(LogLevel::Info, (""));
+  MOZ_LOG_KEY_OR_IME(
+      LogLevel::Info,
+      ("%p TextInputHandler::HandleKeyDownEvent, aNativeEvent=%p, "
+       "type=%s, keyCode=%u (0x%X), modifierFlags=0x%lX, characters=\"%s\", "
+       "charactersIgnoringModifiers=\"%s\"",
+       this, aNativeEvent, GetNativeKeyEventType(aNativeEvent),
+       [aNativeEvent keyCode], [aNativeEvent keyCode],
+       static_cast<unsigned long>([aNativeEvent modifierFlags]),
+       GetCharacters([aNativeEvent characters]),
+       GetCharacters([aNativeEvent charactersIgnoringModifiers])));
+
+  // Except when Command key is pressed, we should hide mouse cursor until
+  // next mousemove.  Handling here means that:
+  // - Don't hide mouse cursor at pressing modifier key
+  // - Hide mouse cursor even if the key event will be handled by IME (i.e.,
+  //   even without dispatching eKeyPress events)
+  // - Hide mouse cursor even when a plugin has focus
+  if (!([aNativeEvent modifierFlags] & NSEventModifierFlagCommand)) {
+    [NSCursor setHiddenUntilMouseMoves:YES];
+  }
+
+  RefPtr<nsChildView> widget(mWidget);
+
+  KeyEventState* currentKeyEvent = PushKeyEvent(aNativeEvent, aUniqueId);
+  AutoKeyEventStateCleaner remover(this);
+
+  RefPtr<TextInputHandler> kungFuDeathGrip(this);
+
+  // When we're already in a composition, we need always to mark the eKeyDown
+  // event as "processed by IME".  So, let's dispatch eKeyDown event here in
+  // such case.
+  if (IsIMEComposing() && !MaybeDispatchCurrentKeydownEvent(true)) {
+    MOZ_LOG_KEY_OR_IME(LogLevel::Info,
+                       ("%p   TextInputHandler::HandleKeyDownEvent, eKeyDown "
+                        "caused focus move or "
+                        "something and canceling the composition",
+                        this));
+    return false;
+  }
+
+  // Let Cocoa interpret the key events, caching IsIMEComposing first.
+  bool wasComposing = IsIMEComposing();
+  bool interpretKeyEventsCalled = false;
+  // Don't call interpretKeyEvents when a plugin has focus.  If we call it,
+  // for example, a character is inputted twice during a composition in e10s
+  // mode.
+  if (IsIMEEnabled() || IsASCIICapableOnly()) {
+    MOZ_LOG_KEY_OR_IME(LogLevel::Info,
+                       ("%p   TextInputHandler::HandleKeyDownEvent, calling "
+                        "interpretKeyEvents",
+                        this));
+    [mView interpretKeyEvents:[NSArray arrayWithObject:aNativeEvent]];
+    interpretKeyEventsCalled = true;
+    MOZ_LOG_KEY_OR_IME(
+        LogLevel::Info,
+        ("%p   TextInputHandler::HandleKeyDownEvent, called interpretKeyEvents",
+         this));
+  }
+
+  if (Destroyed()) {
+    MOZ_LOG_KEY_OR_IME(
+        LogLevel::Info,
+        ("%p   TextInputHandler::HandleKeyDownEvent, widget was destroyed",
+         this));
+    return currentKeyEvent->IsDefaultPrevented();
+  }
+
+  MOZ_LOG_KEY_OR_IME(
+      LogLevel::Info,
+      ("%p   TextInputHandler::HandleKeyDownEvent, wasComposing=%s, "
+       "IsIMEComposing()=%s",
+       this, TrueOrFalse(wasComposing), TrueOrFalse(IsIMEComposing())));
+
+  if (currentKeyEvent->CanDispatchKeyDownEvent()) {
+    // Dispatch eKeyDown event if nobody has dispatched it yet.
+    // NOTE: Although reaching here means that the native keydown event may
+    //       not be handled by IME.  However, we cannot know if it is.
+    //       For example, Japanese IME of Apple shows candidate window for
+    //       typing window.  They, you can switch the sort order with Tab key.
+    //       However, when you choose "Symbol" of the sort order, there may
+    //       be no candiate words.  In this case, IME handles the Tab key
+    //       actually, but we cannot know it because composition string is
+    //       not updated.  So, let's mark eKeyDown event as "processed by IME"
+    //       when there is composition string.  This is same as Chrome.
+    MOZ_LOG_KEY_OR_IME(LogLevel::Info,
+                       ("%p   TextInputHandler::HandleKeyDownEvent, trying to "
+                        "dispatch eKeyDown "
+                        "event since it's not yet dispatched",
+                        this));
+    if (!MaybeDispatchCurrentKeydownEvent(IsIMEComposing())) {
+      return true;  // treat the eKeydDown event as consumed.
+    }
+    MOZ_LOG_KEY_OR_IME(
+        LogLevel::Info,
+        ("%p   TextInputHandler::HandleKeyDownEvent, eKeyDown event has been "
+         "dispatched",
+         this));
+  }
+
+  if (currentKeyEvent->CanDispatchKeyPressEvent() && !wasComposing &&
+      !IsIMEComposing()) {
+    nsresult rv = mDispatcher->BeginNativeInputTransaction();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG_KEY_OR_IME(
+          LogLevel::Error,
+          ("%p   TextInputHandler::HandleKeyDownEvent, "
+           "FAILED, due to BeginNativeInputTransaction() failure "
+           "at dispatching keypress",
+           this));
+      return false;
+    }
+
+    WidgetKeyboardEvent keypressEvent(true, eKeyPress, widget);
+    currentKeyEvent->InitKeyEvent(this, keypressEvent, false);
+
+    // If we called interpretKeyEvents and this isn't normal character input
+    // then IME probably ate the event for some reason. We do not want to
+    // send a key press event in that case.
+    // TODO:
+    // There are some other cases which IME eats the current event.
+    // 1. If key events were nested during calling interpretKeyEvents, it means
+    //    that IME did something.  Then, we should do nothing.
+    // 2. If one or more commands are called like "deleteBackward", we should
+    //    dispatch keypress event at that time.  Note that the command may have
+    //    been a converted or generated action by IME.  Then, we shouldn't do
+    //    our default action for this key.
+    if (!(interpretKeyEventsCalled &&
+          IsNormalCharInputtingEvent(aNativeEvent))) {
+      MOZ_LOG_KEY_OR_IME(
+          LogLevel::Info,
+          ("%p   TextInputHandler::HandleKeyDownEvent, trying to dispatch "
+           "eKeyPress event since it's not yet dispatched",
+           this));
+      nsEventStatus status = nsEventStatus_eIgnore;
+      currentKeyEvent->mKeyPressDispatched =
+          mDispatcher->MaybeDispatchKeypressEvents(keypressEvent, status,
+                                                   currentKeyEvent);
+      currentKeyEvent->mKeyPressHandled =
+          (status == nsEventStatus_eConsumeNoDefault);
+      currentKeyEvent->mKeyPressDispatched = true;
+      MOZ_LOG_KEY_OR_IME(
+          LogLevel::Info,
+          ("%p TextInputHandler::HandleKeyDownEvent, eKeyPress event has been "
+           "dispatched",
+           this));
+    }
+  }
+
+  // Note: mWidget might have become null here. Don't count on it from here on.
+
+  MOZ_LOG_KEY_OR_IME(
+      LogLevel::Info,
+      ("%p   TextInputHandler::HandleKeyDownEvent, "
+       "keydown handled=%s, keypress handled=%s, causedOtherKeyEvents=%s, "
+       "compositionDispatched=%s",
+       this, TrueOrFalse(currentKeyEvent->mKeyDownHandled),
+       TrueOrFalse(currentKeyEvent->mKeyPressHandled),
+       TrueOrFalse(currentKeyEvent->mCausedOtherKeyEvents),
+       TrueOrFalse(currentKeyEvent->mCompositionDispatched)));
+  // Insert empty line to the log for easier to read.
+  MOZ_LOG_KEY_OR_IME(LogLevel::Info, (""));
+  return currentKeyEvent->IsDefaultPrevented();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
+
+void TextInputHandler::HandleKeyUpEvent(NSEvent* aNativeEvent) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_LOG_KEY_OR_IME(
+      LogLevel::Info,
+      ("%p   TextInputHandler::HandleKeyUpEvent, aNativeEvent=%p, "
+       "type=%s, keyCode=%u (0x%X), modifierFlags=0x%lX, characters=\"%s\", "
+       "charactersIgnoringModifiers=\"%s\", "
+       "IsIMEComposing()=%s",
+       this, aNativeEvent, GetNativeKeyEventType(aNativeEvent),
+       [aNativeEvent keyCode], [aNativeEvent keyCode],
+       static_cast<unsigned long>([aNativeEvent modifierFlags]),
+       GetCharacters([aNativeEvent characters]),
+       GetCharacters([aNativeEvent charactersIgnoringModifiers]),
+       TrueOrFalse(IsIMEComposing())));
+
+  if (Destroyed()) {
+    MOZ_LOG_KEY_OR_IME(LogLevel::Info,
+                       ("%p TextInputHandler::HandleKeyUpEvent, "
+                        "widget has been already destroyed",
+                        this));
+    return;
+  }
+
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG_KEY_OR_IME(LogLevel::Error,
+                       ("%p   TextInputHandler::HandleKeyUpEvent, "
+                        "FAILED, due to BeginNativeInputTransaction() failure",
+                        this));
+    return;
+  }
+
+  // Neither Chrome for macOS nor Safari marks "keyup" event as "processed by
+  // IME" even during composition.  So, let's follow this behavior.
+  WidgetKeyboardEvent keyupEvent(true, eKeyUp, mWidget);
+  InitKeyEvent(aNativeEvent, keyupEvent, false);
+
+  KeyEventState currentKeyEvent(aNativeEvent);
+  nsEventStatus status = nsEventStatus_eIgnore;
+  mDispatcher->DispatchKeyboardEvent(eKeyUp, keyupEvent, status,
+                                     &currentKeyEvent);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void TextInputHandler::HandleFlagsChanged(NSEvent* aNativeEvent) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (Destroyed()) {
+    MOZ_LOG_KEY_OR_IME(LogLevel::Info,
+                       ("%p TextInputHandler::HandleFlagsChanged, "
+                        "widget has been already destroyed",
+                        this));
+    return;
+  }
+
+  RefPtr<nsChildView> kungFuDeathGrip(mWidget);
+  mozilla::Unused << kungFuDeathGrip;  // Not referenced within this function
+
+  MOZ_LOG_KEY_OR_IME(
+      LogLevel::Info,
+      ("%p TextInputHandler::HandleFlagsChanged, aNativeEvent=%p, "
+       "type=%s, keyCode=%s (0x%X), modifierFlags=0x%08lX, "
+       "sLastModifierState=0x%08lX, IsIMEComposing()=%s",
+       this, aNativeEvent, GetNativeKeyEventType(aNativeEvent),
+       GetKeyNameForNativeKeyCode([aNativeEvent keyCode]),
+       [aNativeEvent keyCode],
+       static_cast<unsigned long>([aNativeEvent modifierFlags]),
+       static_cast<unsigned long>(sLastModifierState),
+       TrueOrFalse(IsIMEComposing())));
+
+  MOZ_ASSERT([aNativeEvent type] == NSEventTypeFlagsChanged);
+
+  NSUInteger diff = [aNativeEvent modifierFlags] ^ sLastModifierState;
+  // Device dependent flags for left-control key, both shift keys, both command
+  // keys and both option keys have been defined in Next's SDK.  But we
+  // shouldn't use it directly as far as possible since Cocoa SDK doesn't
+  // define them.  Fortunately, we need them only when we dispatch keyup
+  // events.  So, we can usually know the actual relation between keyCode and
+  // device dependent flags.  However, we need to remove following flags first
+  // since the differences don't indicate modifier key state.
+  // NX_STYLUSPROXIMITYMASK: Probably used for pen like device.
+  // kCGEventFlagMaskNonCoalesced (= NX_NONCOALSESCEDMASK): See the document for
+  // Quartz Event Services.
+  diff &= ~(NX_STYLUSPROXIMITYMASK | kCGEventFlagMaskNonCoalesced);
+
+  switch ([aNativeEvent keyCode]) {
+    // CapsLock state and other modifier states are different:
+    // CapsLock state does not revert when the CapsLock key goes up, as the
+    // modifier state does for other modifier keys on key up.
+    case kVK_CapsLock: {
+      // Fire key down event for caps lock.
+      DispatchKeyEventForFlagsChanged(aNativeEvent, true);
+      // XXX should we fire keyup event too? The keyup event for CapsLock key
+      // is never dispatched on Gecko.
+      // XXX WebKit dispatches keydown event when CapsLock is locked, otherwise,
+      // keyup event.  If we do so, we cannot keep the consistency with other
+      // platform's behavior...
+      break;
+    }
+
+    // If the event is caused by pressing or releasing a modifier key, just
+    // dispatch the key's event.
+    case kVK_Shift:
+    case kVK_RightShift:
+    case kVK_Command:
+    case kVK_RightCommand:
+    case kVK_Control:
+    case kVK_RightControl:
+    case kVK_Option:
+    case kVK_RightOption:
+    case kVK_Help: {
+      // We assume that at most one modifier is changed per event if the event
+      // is caused by pressing or releasing a modifier key.
+      bool isKeyDown = ([aNativeEvent modifierFlags] & diff) != 0;
+      DispatchKeyEventForFlagsChanged(aNativeEvent, isKeyDown);
+      // XXX Some applications might send the event with incorrect device-
+      //     dependent flags.
+      if (isKeyDown &&
+          ((diff & ~NSEventModifierFlagDeviceIndependentFlagsMask) != 0)) {
+        unsigned short keyCode = [aNativeEvent keyCode];
+        const ModifierKey* modifierKey =
+            GetModifierKeyForDeviceDependentFlags(diff);
+        if (modifierKey && modifierKey->keyCode != keyCode) {
+          // Although, we're not sure the actual cause of this case, the stored
+          // modifier information and the latest key event information may be
+          // mismatched. Then, let's reset the stored information.
+          // NOTE: If this happens, it may fail to handle
+          // NSEventTypeFlagsChanged event in the default case (below). However,
+          // it's the rare case handler and this case occurs rarely. So, we can
+          // ignore the edge case bug.
+          NS_WARNING("Resetting stored modifier key information");
+          mModifierKeys.Clear();
+          modifierKey = nullptr;
+        }
+        if (!modifierKey) {
+          mModifierKeys.AppendElement(ModifierKey(diff, keyCode));
+        }
+      }
+      break;
+    }
+
+    // Currently we don't support Fn key since other browsers don't dispatch
+    // events for it and we don't have keyCode for this key.
+    // It should be supported when we implement .key and .char.
+    case kVK_Function:
+      break;
+
+    // If the event is caused by something else than pressing or releasing a
+    // single modifier key (for example by the app having been deactivated
+    // using command-tab), use the modifiers themselves to determine which
+    // key's event to dispatch, and whether it's a keyup or keydown event.
+    // In all cases we assume one or more modifiers are being deactivated
+    // (never activated) -- otherwise we'd have received one or more events
+    // corresponding to a single modifier key being pressed.
+    default: {
+      NSUInteger modifiers = sLastModifierState;
+      AutoTArray<unsigned short, 10> dispatchedKeyCodes;
+      for (int32_t bit = 0; bit < 32; ++bit) {
+        NSUInteger flag = 1 << bit;
+        if (!(diff & flag)) {
+          continue;
+        }
+
+        // Given correct information from the application, a flag change here
+        // will normally be a deactivation (except for some lockable modifiers
+        // such as CapsLock).  But some applications (like VNC) can send an
+        // activating event with a zero keyCode.  So we need to check for that
+        // here.
+        bool dispatchKeyDown = ((flag & [aNativeEvent modifierFlags]) != 0);
+
+        unsigned short keyCode = 0;
+        if (flag & NSEventModifierFlagDeviceIndependentFlagsMask) {
+          switch (flag) {
+            case NSEventModifierFlagCapsLock:
+              keyCode = kVK_CapsLock;
+              dispatchKeyDown = true;
+              break;
+
+            case NSEventModifierFlagNumericPad:
+              // NSEventModifierFlagNumericPad is fired by VNC a lot. But not
+              // all of these events can really be Clear key events, so we just
+              // ignore them.
+              continue;
+
+            case NSEventModifierFlagHelp:
+              keyCode = kVK_Help;
+              break;
+
+            case NSEventModifierFlagFunction:
+              // An NSEventModifierFlagFunction change here will normally be a
+              // deactivation.  But sometimes it will be an activation send (by
+              // VNC for example) with a zero keyCode.
+              continue;
+
+            // These cases (NSEventModifierFlagShift,
+            // NSEventModifierFlagControl, NSEventModifierFlagOption and
+            // NSEventModifierFlagCommand) should be handled by the other branch
+            // of the if statement, below (which handles device dependent
+            // flags). However, some applications (like VNC) can send key events
+            // without any device dependent flags, so we handle them here
+            // instead.
+            case NSEventModifierFlagShift:
+              keyCode = (modifiers & 0x0004) ? kVK_RightShift : kVK_Shift;
+              break;
+            case NSEventModifierFlagControl:
+              keyCode = (modifiers & 0x2000) ? kVK_RightControl : kVK_Control;
+              break;
+            case NSEventModifierFlagOption:
+              keyCode = (modifiers & 0x0040) ? kVK_RightOption : kVK_Option;
+              break;
+            case NSEventModifierFlagCommand:
+              keyCode = (modifiers & 0x0010) ? kVK_RightCommand : kVK_Command;
+              break;
+
+            default:
+              continue;
+          }
+        } else {
+          const ModifierKey* modifierKey =
+              GetModifierKeyForDeviceDependentFlags(flag);
+          if (!modifierKey) {
+            // See the note above (in the other branch of the if statement)
+            // about the NSEventModifierFlagShift, NSEventModifierFlagControl,
+            // NSEventModifierFlagOption and NSEventModifierFlagCommand cases.
+            continue;
+          }
+          keyCode = modifierKey->keyCode;
+        }
+
+        // Remove flags
+        modifiers &= ~flag;
+        switch (keyCode) {
+          case kVK_Shift: {
+            const ModifierKey* modifierKey =
+                GetModifierKeyForNativeKeyCode(kVK_RightShift);
+            if (!modifierKey ||
+                !(modifiers & modifierKey->GetDeviceDependentFlags())) {
+              modifiers &= ~NSEventModifierFlagShift;
+            }
+            break;
+          }
+          case kVK_RightShift: {
+            const ModifierKey* modifierKey =
+                GetModifierKeyForNativeKeyCode(kVK_Shift);
+            if (!modifierKey ||
+                !(modifiers & modifierKey->GetDeviceDependentFlags())) {
+              modifiers &= ~NSEventModifierFlagShift;
+            }
+            break;
+          }
+          case kVK_Command: {
+            const ModifierKey* modifierKey =
+                GetModifierKeyForNativeKeyCode(kVK_RightCommand);
+            if (!modifierKey ||
+                !(modifiers & modifierKey->GetDeviceDependentFlags())) {
+              modifiers &= ~NSEventModifierFlagCommand;
+            }
+            break;
+          }
+          case kVK_RightCommand: {
+            const ModifierKey* modifierKey =
+                GetModifierKeyForNativeKeyCode(kVK_Command);
+            if (!modifierKey ||
+                !(modifiers & modifierKey->GetDeviceDependentFlags())) {
+              modifiers &= ~NSEventModifierFlagCommand;
+            }
+            break;
+          }
+          case kVK_Control: {
+            const ModifierKey* modifierKey =
+                GetModifierKeyForNativeKeyCode(kVK_RightControl);
+            if (!modifierKey ||
+                !(modifiers & modifierKey->GetDeviceDependentFlags())) {
+              modifiers &= ~NSEventModifierFlagControl;
+            }
+            break;
+          }
+          case kVK_RightControl: {
+            const ModifierKey* modifierKey =
+                GetModifierKeyForNativeKeyCode(kVK_Control);
+            if (!modifierKey ||
+                !(modifiers & modifierKey->GetDeviceDependentFlags())) {
+              modifiers &= ~NSEventModifierFlagControl;
+            }
+            break;
+          }
+          case kVK_Option: {
+            const ModifierKey* modifierKey =
+                GetModifierKeyForNativeKeyCode(kVK_RightOption);
+            if (!modifierKey ||
+                !(modifiers & modifierKey->GetDeviceDependentFlags())) {
+              modifiers &= ~NSEventModifierFlagOption;
+            }
+            break;
+          }
+          case kVK_RightOption: {
+            const ModifierKey* modifierKey =
+                GetModifierKeyForNativeKeyCode(kVK_Option);
+            if (!modifierKey ||
+                !(modifiers & modifierKey->GetDeviceDependentFlags())) {
+              modifiers &= ~NSEventModifierFlagOption;
+            }
+            break;
+          }
+          case kVK_Help:
+            modifiers &= ~NSEventModifierFlagHelp;
+            break;
+          default:
+            break;
+        }
+
+        // Avoid dispatching same keydown/keyup events twice or more.
+        // We must be able to assume that there is no case to dispatch
+        // both keydown and keyup events with same key code value here.
+        if (dispatchedKeyCodes.Contains(keyCode)) {
+          continue;
+        }
+        dispatchedKeyCodes.AppendElement(keyCode);
+
+        NSEvent* event =
+            [NSEvent keyEventWithType:NSEventTypeFlagsChanged
+                                   location:[aNativeEvent locationInWindow]
+                              modifierFlags:modifiers
+                                  timestamp:[aNativeEvent timestamp]
+                               windowNumber:[aNativeEvent windowNumber]
+                                    context:nil
+                                 characters:@""
+                charactersIgnoringModifiers:@""
+                                  isARepeat:NO
+                                    keyCode:keyCode];
+        DispatchKeyEventForFlagsChanged(event, dispatchKeyDown);
+        if (Destroyed()) {
+          break;
+        }
+
+        // Stop if focus has changed.
+        // Check to see if mView is still the first responder.
+        if (![mView isFirstResponder]) {
+          break;
+        }
+      }
+      break;
+    }
+  }
+
+  // Be aware, the widget may have been destroyed.
+  sLastModifierState = [aNativeEvent modifierFlags];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+const TextInputHandler::ModifierKey*
+TextInputHandler::GetModifierKeyForNativeKeyCode(
+    unsigned short aKeyCode) const {
+  for (ModifierKeyArray::index_type i = 0; i < mModifierKeys.Length(); ++i) {
+    if (mModifierKeys[i].keyCode == aKeyCode) {
+      return &((ModifierKey&)mModifierKeys[i]);
+    }
+  }
+  return nullptr;
+}
+
+const TextInputHandler::ModifierKey*
+TextInputHandler::GetModifierKeyForDeviceDependentFlags(
+    NSUInteger aFlags) const {
+  for (ModifierKeyArray::index_type i = 0; i < mModifierKeys.Length(); ++i) {
+    if (mModifierKeys[i].GetDeviceDependentFlags() ==
+        (aFlags & ~NSEventModifierFlagDeviceIndependentFlagsMask)) {
+      return &((ModifierKey&)mModifierKeys[i]);
+    }
+  }
+  return nullptr;
+}
+
+void TextInputHandler::DispatchKeyEventForFlagsChanged(NSEvent* aNativeEvent,
+                                                       bool aDispatchKeyDown) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (Destroyed()) {
+    return;
+  }
+
+  MOZ_LOG_KEY_OR_IME(
+      LogLevel::Info,
+      ("%p TextInputHandler::DispatchKeyEventForFlagsChanged, aNativeEvent=%p, "
+       "type=%s, keyCode=%s (0x%X), aDispatchKeyDown=%s, IsIMEComposing()=%s",
+       this, aNativeEvent, GetNativeKeyEventType(aNativeEvent),
+       GetKeyNameForNativeKeyCode([aNativeEvent keyCode]),
+       [aNativeEvent keyCode], TrueOrFalse(aDispatchKeyDown),
+       TrueOrFalse(IsIMEComposing())));
+
+  if ([aNativeEvent type] != NSEventTypeFlagsChanged) {
+    return;
+  }
+
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG_KEY_OR_IME(
+        LogLevel::Error,
+        ("%p   TextInputHandler::DispatchKeyEventForFlagsChanged, "
+         "FAILED, due to BeginNativeInputTransaction() failure",
+         this));
+    return;
+  }
+
+  EventMessage message = aDispatchKeyDown ? eKeyDown : eKeyUp;
+
+  // Fire a key event for the modifier key.  Note that even if modifier key
+  // is pressed during composition, we shouldn't mark the keyboard event as
+  // "processed by IME" since neither Chrome for macOS nor Safari does it.
+  WidgetKeyboardEvent keyEvent(true, message, mWidget);
+  InitKeyEvent(aNativeEvent, keyEvent, false);
+
+  KeyEventState currentKeyEvent(aNativeEvent);
+  nsEventStatus status = nsEventStatus_eIgnore;
+  mDispatcher->DispatchKeyboardEvent(message, keyEvent, status,
+                                     &currentKeyEvent);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void TextInputHandler::InsertText(NSString* aString,
+                                  NSRange* aReplacementRange) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (Destroyed()) {
+    return;
+  }
+
+  KeyEventState* currentKeyEvent = GetCurrentKeyEvent();
+
+  MOZ_LOG_KEY_OR_IME(
+      LogLevel::Info,
+      ("%p TextInputHandler::InsertText, aString=\"%s\", "
+       "aReplacementRange=%p { location=%lu, length=%lu }, "
+       "IsIMEComposing()=%s, "
+       "keyevent=%p, keydownDispatched=%s, "
+       "keydownHandled=%s, keypressDispatched=%s, "
+       "causedOtherKeyEvents=%s, compositionDispatched=%s",
+       this, GetCharacters(aString), aReplacementRange,
+       static_cast<unsigned long>(
+           aReplacementRange ? aReplacementRange->location : 0),
+       static_cast<unsigned long>(aReplacementRange ? aReplacementRange->length
+                                                    : 0),
+       TrueOrFalse(IsIMEComposing()),
+       currentKeyEvent ? currentKeyEvent->mKeyEvent : nullptr,
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyDownDispatched)
+                       : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyDownHandled) : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyPressDispatched)
+                       : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mCausedOtherKeyEvents)
+                       : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mCompositionDispatched)
+                       : "N/A"));
+
+  InputContext context = mWidget->GetInputContext();
+  bool isEditable = (context.mIMEState.mEnabled == IMEEnabled::Enabled ||
+                     context.mIMEState.mEnabled == IMEEnabled::Password);
+  NSRange selectedRange = SelectedRange();
+
+  nsAutoString str;
+  nsCocoaUtils::GetStringForNSString(aString, str);
+
+  AutoInsertStringClearer clearer(currentKeyEvent);
+  if (currentKeyEvent) {
+    currentKeyEvent->mInsertString = &str;
+  }
+
+  if (!IsIMEComposing() && str.IsEmpty()) {
+    // nothing to do if there is no content which can be removed.
+    if (!isEditable) {
+      return;
+    }
+    // If replacement range is specified, we need to remove the range.
+    // Otherwise, we need to remove the selected range if it's not collapsed.
+    if (aReplacementRange && aReplacementRange->location != NSNotFound) {
+      // nothing to do since the range is collapsed.
+      if (aReplacementRange->length == 0) {
+        return;
+      }
+      // If the replacement range is different from current selected range,
+      // select the range.
+      if (!NSEqualRanges(selectedRange, *aReplacementRange)) {
+        NS_ENSURE_TRUE_VOID(SetSelection(*aReplacementRange));
+      }
+      selectedRange = SelectedRange();
+    }
+    NS_ENSURE_TRUE_VOID(selectedRange.location != NSNotFound);
+    if (selectedRange.length == 0) {
+      return;  // nothing to do
+    }
+    // If this is caused by a key input, the keypress event which will be
+    // dispatched later should cause the delete.  Therefore, nothing to do here.
+    // Although, we're not sure if such case is actually possible.
+    if (!currentKeyEvent) {
+      return;
+    }
+
+    // When current keydown event causes this empty text input, let's
+    // dispatch eKeyDown event before any other events.  Note that if we're
+    // in a composition, we've already dispatched eKeyDown event from
+    // TextInputHandler::HandleKeyDownEvent().
+    // XXX Should we mark this eKeyDown event as "processed by IME"?
+    RefPtr<TextInputHandler> kungFuDeathGrip(this);
+    if (!IsIMEComposing() && !MaybeDispatchCurrentKeydownEvent(false)) {
+      MOZ_LOG_KEY_OR_IME(
+          LogLevel::Info,
+          ("%p   TextInputHandler::InsertText, eKeyDown caused focus move or "
+           "something and canceling the composition",
+           this));
+      return;
+    }
+
+    // Delete the selected range.
+    WidgetContentCommandEvent deleteCommandEvent(true, eContentCommandDelete,
+                                                 mWidget);
+    DispatchEvent(deleteCommandEvent);
+    NS_ENSURE_TRUE_VOID(deleteCommandEvent.mSucceeded);
+    // Be aware! The widget might be destroyed here.
+    return;
+  }
+
+  bool isReplacingSpecifiedRange =
+      isEditable && aReplacementRange &&
+      aReplacementRange->location != NSNotFound &&
+      !NSEqualRanges(selectedRange, *aReplacementRange);
+
+  // If this is not caused by pressing a key, there is a composition or
+  // replacing a range which is different from current selection, let's
+  // insert the text as committing a composition.
+  // If InsertText() is called two or more times, we should insert all
+  // text with composition events.
+  // XXX When InsertText() is called multiple times, Chromium dispatches
+  //     only one composition event.  So, we need to store InsertText()
+  //     calls and flush later.
+  if (!currentKeyEvent || currentKeyEvent->mCompositionDispatched ||
+      IsIMEComposing() || isReplacingSpecifiedRange) {
+    InsertTextAsCommittingComposition(aString, aReplacementRange);
+    if (currentKeyEvent) {
+      currentKeyEvent->mCompositionDispatched = true;
+    }
+    return;
+  }
+
+  // Don't let the same event be fired twice when hitting
+  // enter/return for Bug 420502.  However, Korean IME (or some other
+  // simple IME) may work without marked text.  For example, composing
+  // character may be inserted as committed text and it's modified with
+  // aReplacementRange.  When a keydown starts new composition with
+  // committing previous character, InsertText() may be called twice,
+  // one is for committing previous character and then, inserting new
+  // composing character as committed character.  In the latter case,
+  // |CanDispatchKeyPressEvent()| returns true but we need to dispatch
+  // keypress event for the new character.  So, when IME tries to insert
+  // printable characters, we should ignore current key event state even
+  // after the keydown has already caused dispatching composition event.
+  // XXX Anyway, we should sort out around this at fixing bug 1338460.
+  if (currentKeyEvent && !currentKeyEvent->CanDispatchKeyPressEvent() &&
+      (str.IsEmpty() || (str.Length() == 1 && !IsPrintableChar(str[0])))) {
+    return;
+  }
+
+  // This is the normal path to input a character when you press a key.
+  // Let's dispatch eKeyDown event now.
+  RefPtr<TextInputHandler> kungFuDeathGrip(this);
+  if (!MaybeDispatchCurrentKeydownEvent(false)) {
+    MOZ_LOG_KEY_OR_IME(
+        LogLevel::Info,
+        ("%p   TextInputHandler::InsertText, eKeyDown caused focus move or "
+         "something and canceling the composition",
+         this));
+    return;
+  }
+
+  // XXX Shouldn't we hold mDispatcher instead of mWidget?
+  RefPtr<nsChildView> widget(mWidget);
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG_KEY_OR_IME(LogLevel::Error,
+                       ("%p   TextInputHandler::InsertText, "
+                        "FAILED, due to BeginNativeInputTransaction() failure",
+                        this));
+    return;
+  }
+
+  MOZ_LOG_KEY_OR_IME(LogLevel::Info, ("%p   TextInputHandler::InsertText, "
+                                      "maybe dispatches eKeyPress event "
+                                      "without control, alt and meta modifiers",
+                                      this));
+
+  // Dispatch keypress event with char instead of compositionchange event
+  WidgetKeyboardEvent keypressEvent(true, eKeyPress, widget);
+  // XXX Why do we need to dispatch keypress event for not inputting any
+  //     string?  If it wants to delete the specified range, should we
+  //     dispatch an eContentCommandDelete event instead?  Because this
+  //     must not be caused by a key operation, a part of IME's processing.
+
+  // Don't set other modifiers from the current event, because here in
+  // -insertText: they've already been taken into account in creating
+  // the input string.
+
+  if (currentKeyEvent) {
+    currentKeyEvent->InitKeyEvent(this, keypressEvent, false);
+  } else {
+    nsCocoaUtils::InitInputEvent(keypressEvent, static_cast<NSEvent*>(nullptr));
+    keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_USE_STRING;
+    keypressEvent.mKeyValue = str;
+    // FYI: TextEventDispatcher will set mKeyCode to 0 for printable key's
+    //      keypress events even if they don't cause inputting non-empty string.
+  }
+
+  // TODO:
+  // If mCurrentKeyEvent.mKeyEvent is null, the text should be inputted as
+  // composition events.
+  nsEventStatus status = nsEventStatus_eIgnore;
+  bool keyPressDispatched = mDispatcher->MaybeDispatchKeypressEvents(
+      keypressEvent, status, currentKeyEvent);
+  bool keyPressHandled = (status == nsEventStatus_eConsumeNoDefault);
+
+  // Note: mWidget might have become null here. Don't count on it from here on.
+
+  if (currentKeyEvent) {
+    currentKeyEvent->mKeyPressHandled = keyPressHandled;
+    currentKeyEvent->mKeyPressDispatched = keyPressDispatched;
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+bool TextInputHandler::HandleCommand(Command aCommand) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (Destroyed()) {
+    return false;
+  }
+
+  KeyEventState* currentKeyEvent = GetCurrentKeyEvent();
+
+  MOZ_LOG_KEY_OR_IME(
+      LogLevel::Info,
+      ("%p TextInputHandler::HandleCommand, "
+       "aCommand=%s, IsIMEComposing()=%s, "
+       "keyevent=%p, keydownHandled=%s, keypressDispatched=%s, "
+       "causedOtherKeyEvents=%s, compositionDispatched=%s",
+       this, ToChar(aCommand), TrueOrFalse(IsIMEComposing()),
+       currentKeyEvent ? currentKeyEvent->mKeyEvent : nullptr,
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyDownHandled) : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyPressDispatched)
+                       : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mCausedOtherKeyEvents)
+                       : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mCompositionDispatched)
+                       : "N/A"));
+
+  // The command shouldn't be handled, let's ignore it.
+  if (currentKeyEvent && !currentKeyEvent->CanHandleCommand()) {
+    return false;
+  }
+
+  // When current keydown event causes this command, let's dispatch
+  // eKeyDown event before any other events.  Note that if we're in a
+  // composition, we've already dispatched eKeyDown event from
+  // TextInputHandler::HandleKeyDownEvent().
+  RefPtr<TextInputHandler> kungFuDeathGrip(this);
+  if (!IsIMEComposing() && !MaybeDispatchCurrentKeydownEvent(false)) {
+    MOZ_LOG_KEY_OR_IME(
+        LogLevel::Info,
+        ("%p   TextInputHandler::SetMarkedText, eKeyDown caused focus move or "
+         "something and canceling the composition",
+         this));
+    return false;
+  }
+
+  // If it's in composition, we cannot dispatch keypress event.
+  // Therefore, we should use different approach or give up to handle
+  // the command.
+  if (IsIMEComposing()) {
+    switch (aCommand) {
+      case Command::InsertLineBreak:
+      case Command::InsertParagraph: {
+        // Insert '\n' as committing composition.
+        // Otherwise, we need to dispatch keypress event because HTMLEditor
+        // doesn't treat "\n" in composition string as a line break unless
+        // the whitespace is treated as pre (see bug 1350541).  In strictly
+        // speaking, we should dispatch keypress event as-is if it's handling
+        // NSEventTypeKeyDown event or should insert it with committing
+        // composition.
+        InsertTextAsCommittingComposition(@"\n", nullptr);
+        if (currentKeyEvent) {
+          currentKeyEvent->mCompositionDispatched = true;
+        }
+        return true;
+      }
+      case Command::DeleteCharBackward:
+      case Command::DeleteCharForward:
+      case Command::DeleteToBeginningOfLine:
+      case Command::DeleteWordBackward:
+      case Command::DeleteWordForward:
+        // Don't remove any contents during composition.
+        return false;
+      case Command::InsertTab:
+      case Command::InsertBacktab:
+        // Don't move focus during composition.
+        return false;
+      case Command::CharNext:
+      case Command::SelectCharNext:
+      case Command::WordNext:
+      case Command::SelectWordNext:
+      case Command::EndLine:
+      case Command::SelectEndLine:
+      case Command::CharPrevious:
+      case Command::SelectCharPrevious:
+      case Command::WordPrevious:
+      case Command::SelectWordPrevious:
+      case Command::BeginLine:
+      case Command::SelectBeginLine:
+      case Command::LinePrevious:
+      case Command::SelectLinePrevious:
+      case Command::MoveTop:
+      case Command::LineNext:
+      case Command::SelectLineNext:
+      case Command::MoveBottom:
+      case Command::SelectBottom:
+      case Command::SelectPageUp:
+      case Command::SelectPageDown:
+      case Command::ScrollBottom:
+      case Command::ScrollTop:
+        // Don't move selection during composition.
+        return false;
+      case Command::CancelOperation:
+      case Command::Complete:
+        // Don't handle Escape key by ourselves during composition.
+        return false;
+      case Command::ScrollPageUp:
+      case Command::ScrollPageDown:
+        // Allow to scroll.
+        break;
+      default:
+        break;
+    }
+  }
+
+  RefPtr<nsChildView> widget(mWidget);
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG_KEY_OR_IME(LogLevel::Error,
+                       ("%p,   TextInputHandler::HandleCommand, "
+                        "FAILED, due to BeginNativeInputTransaction() failure",
+                        this));
+    return false;
+  }
+
+  // TODO: If it's not appropriate keypress but user customized the OS
+  //       settings to do the command with other key, we should just set
+  //       command to the keypress event and it should be handled as
+  //       the key press in editor.
+
+  // If it's handling actual key event and hasn't cause any composition
+  // events nor other key events, we should expose actual modifier state.
+  // Otherwise, we should adjust Control, Option and Command state since
+  // editor may behave differently if some of them are active.
+  bool dispatchFakeKeyPress =
+      !(currentKeyEvent && currentKeyEvent->IsProperKeyEvent(aCommand));
+
+  WidgetKeyboardEvent keydownEvent(true, eKeyDown, widget);
+  WidgetKeyboardEvent keypressEvent(true, eKeyPress, widget);
+  if (!dispatchFakeKeyPress) {
+    // If we're acutally handling a key press, we should dispatch
+    // the keypress event as-is.
+    currentKeyEvent->InitKeyEvent(this, keydownEvent, false);
+    currentKeyEvent->InitKeyEvent(this, keypressEvent, false);
+  } else {
+    // Otherwise, we should dispatch "fake" keypress event.
+    // However, for making it possible to compute edit commands, we need to
+    // set current native key event to the fake keyboard event even if it's
+    // not same as what we expect since the native keyboard event caused
+    // this command.
+    NSEvent* keyEvent = currentKeyEvent ? currentKeyEvent->mKeyEvent : nullptr;
+    keydownEvent.mNativeKeyEvent = keypressEvent.mNativeKeyEvent = keyEvent;
+    NS_WARNING_ASSERTION(
+        keypressEvent.mNativeKeyEvent,
+        "Without native key event, NativeKeyBindings cannot compute aCommand");
+    switch (aCommand) {
+      case Command::InsertLineBreak:
+      case Command::InsertParagraph: {
+        // Although, Shift+Enter and Enter are work differently in HTML
+        // editor, we should expose actual Shift state if it's caused by
+        // Enter key for compatibility with Chromium.  Chromium breaks
+        // line in HTML editor with default pargraph separator when Enter
+        // is pressed, with <br> element when Shift+Enter.  Safari breaks
+        // line in HTML editor with default paragraph separator when
+        // Enter, Shift+Enter or Option+Enter.  So, we should not change
+        // Shift+Enter meaning when there was composition string or not.
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        keypressEvent.mKeyCode = NS_VK_RETURN;
+        keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_Enter;
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        if (aCommand == Command::InsertLineBreak) {
+          // In default settings, Ctrl + Enter causes insertLineBreak command.
+          // So, let's make Ctrl state active of the keypress event.
+          keypressEvent.mModifiers |= MODIFIER_CONTROL;
+        }
+        break;
+      }
+      case Command::InsertTab:
+      case Command::InsertBacktab:
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        keypressEvent.mKeyCode = NS_VK_TAB;
+        keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_Tab;
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        if (aCommand == Command::InsertBacktab) {
+          keypressEvent.mModifiers |= MODIFIER_SHIFT;
+        }
+        break;
+      case Command::DeleteCharBackward:
+      case Command::DeleteToBeginningOfLine:
+      case Command::DeleteWordBackward: {
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        keypressEvent.mKeyCode = NS_VK_BACK;
+        keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_Backspace;
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        if (aCommand == Command::DeleteToBeginningOfLine) {
+          keypressEvent.mModifiers |= MODIFIER_META;
+        } else if (aCommand == Command::DeleteWordBackward) {
+          keypressEvent.mModifiers |= MODIFIER_ALT;
+        }
+        break;
+      }
+      case Command::DeleteCharForward:
+      case Command::DeleteWordForward: {
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        keypressEvent.mKeyCode = NS_VK_DELETE;
+        keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_Delete;
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        if (aCommand == Command::DeleteWordForward) {
+          keypressEvent.mModifiers |= MODIFIER_ALT;
+        }
+        break;
+      }
+      case Command::CharNext:
+      case Command::SelectCharNext:
+      case Command::WordNext:
+      case Command::SelectWordNext:
+      case Command::EndLine:
+      case Command::SelectEndLine: {
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        keypressEvent.mKeyCode = NS_VK_RIGHT;
+        keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_ArrowRight;
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        if (aCommand == Command::SelectCharNext ||
+            aCommand == Command::SelectWordNext ||
+            aCommand == Command::SelectEndLine) {
+          keypressEvent.mModifiers |= MODIFIER_SHIFT;
+        }
+        if (aCommand == Command::WordNext ||
+            aCommand == Command::SelectWordNext) {
+          keypressEvent.mModifiers |= MODIFIER_ALT;
+        }
+        if (aCommand == Command::EndLine ||
+            aCommand == Command::SelectEndLine) {
+          keypressEvent.mModifiers |= MODIFIER_META;
+        }
+        break;
+      }
+      case Command::CharPrevious:
+      case Command::SelectCharPrevious:
+      case Command::WordPrevious:
+      case Command::SelectWordPrevious:
+      case Command::BeginLine:
+      case Command::SelectBeginLine: {
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        keypressEvent.mKeyCode = NS_VK_LEFT;
+        keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_ArrowLeft;
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        if (aCommand == Command::SelectCharPrevious ||
+            aCommand == Command::SelectWordPrevious ||
+            aCommand == Command::SelectBeginLine) {
+          keypressEvent.mModifiers |= MODIFIER_SHIFT;
+        }
+        if (aCommand == Command::WordPrevious ||
+            aCommand == Command::SelectWordPrevious) {
+          keypressEvent.mModifiers |= MODIFIER_ALT;
+        }
+        if (aCommand == Command::BeginLine ||
+            aCommand == Command::SelectBeginLine) {
+          keypressEvent.mModifiers |= MODIFIER_META;
+        }
+        break;
+      }
+      case Command::LinePrevious:
+      case Command::SelectLinePrevious:
+      case Command::MoveTop:
+      case Command::SelectTop: {
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        keypressEvent.mKeyCode = NS_VK_UP;
+        keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_ArrowUp;
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        if (aCommand == Command::SelectLinePrevious ||
+            aCommand == Command::SelectTop) {
+          keypressEvent.mModifiers |= MODIFIER_SHIFT;
+        }
+        if (aCommand == Command::MoveTop || aCommand == Command::SelectTop) {
+          keypressEvent.mModifiers |= MODIFIER_META;
+        }
+        break;
+      }
+      case Command::LineNext:
+      case Command::SelectLineNext:
+      case Command::MoveBottom:
+      case Command::SelectBottom: {
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        keypressEvent.mKeyCode = NS_VK_DOWN;
+        keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_ArrowDown;
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        if (aCommand == Command::SelectLineNext ||
+            aCommand == Command::SelectBottom) {
+          keypressEvent.mModifiers |= MODIFIER_SHIFT;
+        }
+        if (aCommand == Command::MoveBottom ||
+            aCommand == Command::SelectBottom) {
+          keypressEvent.mModifiers |= MODIFIER_META;
+        }
+        break;
+      }
+      case Command::ScrollPageUp:
+      case Command::SelectPageUp: {
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        keypressEvent.mKeyCode = NS_VK_PAGE_UP;
+        keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_PageUp;
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        if (aCommand == Command::SelectPageUp) {
+          keypressEvent.mModifiers |= MODIFIER_SHIFT;
+        }
+        break;
+      }
+      case Command::ScrollPageDown:
+      case Command::SelectPageDown: {
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        keypressEvent.mKeyCode = NS_VK_PAGE_DOWN;
+        keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_PageDown;
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        if (aCommand == Command::SelectPageDown) {
+          keypressEvent.mModifiers |= MODIFIER_SHIFT;
+        }
+        break;
+      }
+      case Command::ScrollBottom:
+      case Command::ScrollTop: {
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        if (aCommand == Command::ScrollBottom) {
+          keypressEvent.mKeyCode = NS_VK_END;
+          keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_End;
+        } else {
+          keypressEvent.mKeyCode = NS_VK_HOME;
+          keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_Home;
+        }
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        break;
+      }
+      case Command::CancelOperation:
+      case Command::Complete: {
+        nsCocoaUtils::InitInputEvent(keypressEvent, keyEvent);
+        keypressEvent.mKeyCode = NS_VK_ESCAPE;
+        keypressEvent.mKeyNameIndex = KEY_NAME_INDEX_Escape;
+        keypressEvent.mModifiers &=
+            ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+        if (aCommand == Command::Complete) {
+          keypressEvent.mModifiers |= MODIFIER_ALT;
+        }
+        break;
+      }
+      default:
+        return false;
+    }
+
+    nsCocoaUtils::InitInputEvent(keydownEvent, keyEvent);
+    keydownEvent.mKeyCode = keypressEvent.mKeyCode;
+    keydownEvent.mKeyNameIndex = keypressEvent.mKeyNameIndex;
+    keydownEvent.mModifiers = keypressEvent.mModifiers;
+  }
+
+  // We've stopped dispatching "keypress" events of non-printable keys on
+  // the web.  Therefore, we need to dispatch eKeyDown event here for web
+  // apps.  This is non-standard behavior if we've already dispatched a
+  // "keydown" event.  However, Chrome also dispatches such fake "keydown"
+  // (and "keypress") event for making same behavior as Safari.
+  nsEventStatus status = nsEventStatus_eIgnore;
+  if (mDispatcher->DispatchKeyboardEvent(eKeyDown, keydownEvent, status,
+                                         nullptr)) {
+    bool keydownHandled = status == nsEventStatus_eConsumeNoDefault;
+    if (currentKeyEvent) {
+      currentKeyEvent->mKeyDownDispatched = true;
+      currentKeyEvent->mKeyDownHandled |= keydownHandled;
+    }
+    if (keydownHandled) {
+      // Don't dispatch eKeyPress event if preceding eKeyDown event is
+      // consumed for conforming to UI Events.
+      // XXX Perhaps, we should ignore previous eKeyDown event result
+      //     even if we've already dispatched because it may notify web apps
+      //     of different key information, e.g., it's handled by IME, but
+      //     web apps want to handle only this key.
+      return true;
+    }
+  }
+
+  bool keyPressDispatched = mDispatcher->MaybeDispatchKeypressEvents(
+      keypressEvent, status, currentKeyEvent);
+  bool keyPressHandled = (status == nsEventStatus_eConsumeNoDefault);
+
+  // NOTE: mWidget might have become null here.
+
+  if (keyPressDispatched) {
+    // Record the keypress event state only when it dispatched actual Enter
+    // keypress event because in other cases, the keypress event just a
+    // messenger.  E.g., if it's caused by different key, keypress event for
+    // the actual key should be dispatched.
+    if (!dispatchFakeKeyPress && currentKeyEvent) {
+      currentKeyEvent->mKeyPressHandled = keyPressHandled;
+      currentKeyEvent->mKeyPressDispatched = keyPressDispatched;
+    }
+    return true;
+  }
+
+  // If keypress event isn't dispatched as expected, we should fallback to
+  // using composition events.
+  if (aCommand == Command::InsertLineBreak ||
+      aCommand == Command::InsertParagraph) {
+    InsertTextAsCommittingComposition(@"\n", nullptr);
+    if (currentKeyEvent) {
+      currentKeyEvent->mCompositionDispatched = true;
+    }
+    return true;
+  }
+
+  return false;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
+
+bool TextInputHandler::DoCommandBySelector(const char* aSelector) {
+  RefPtr<nsChildView> widget(mWidget);
+
+  KeyEventState* currentKeyEvent = GetCurrentKeyEvent();
+
+  MOZ_LOG_KEY_OR_IME(
+      LogLevel::Info,
+      ("%p TextInputHandler::DoCommandBySelector, aSelector=\"%s\", "
+       "Destroyed()=%s, keydownDispatched=%s, keydownHandled=%s, "
+       "keypressDispatched=%s, keypressHandled=%s, causedOtherKeyEvents=%s",
+       this, aSelector ? aSelector : "", TrueOrFalse(Destroyed()),
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyDownDispatched)
+                       : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyDownHandled) : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyPressDispatched)
+                       : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyPressHandled) : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mCausedOtherKeyEvents)
+                       : "N/A"));
+
+  // If the command isn't caused by key operation, the command should
+  // be handled in the super class of the caller.
+  if (!currentKeyEvent) {
+    return Destroyed();
+  }
+
+  // When current keydown event causes this command, let's dispatch
+  // eKeyDown event before any other events.  Note that if we're in a
+  // composition, we've already dispatched eKeyDown event from
+  // TextInputHandler::HandleKeyDownEvent().
+  RefPtr<TextInputHandler> kungFuDeathGrip(this);
+  if (!IsIMEComposing() && !MaybeDispatchCurrentKeydownEvent(false)) {
+    MOZ_LOG_KEY_OR_IME(
+        LogLevel::Info,
+        ("%p   TextInputHandler::SetMarkedText, eKeyDown caused focus move or "
+         "something and canceling the composition",
+         this));
+    return true;
+  }
+
+  // If the key operation causes this command, should dispatch a keypress
+  // event.
+  // XXX This must be worng.  Even if this command is caused by the key
+  //     operation, its our default action can be different from the
+  //     command.  So, in this case, we should dispatch a keypress event
+  //     which have the command and editor should handle it.
+  if (currentKeyEvent->CanDispatchKeyPressEvent()) {
+    nsresult rv = mDispatcher->BeginNativeInputTransaction();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG_KEY_OR_IME(
+          LogLevel::Error,
+          ("%p   TextInputHandler::DoCommandBySelector, "
+           "FAILED, due to BeginNativeInputTransaction() failure "
+           "at dispatching keypress",
+           this));
+      return Destroyed();
+    }
+
+    WidgetKeyboardEvent keypressEvent(true, eKeyPress, widget);
+    currentKeyEvent->InitKeyEvent(this, keypressEvent, false);
+
+    nsEventStatus status = nsEventStatus_eIgnore;
+    currentKeyEvent->mKeyPressDispatched =
+        mDispatcher->MaybeDispatchKeypressEvents(keypressEvent, status,
+                                                 currentKeyEvent);
+    currentKeyEvent->mKeyPressHandled =
+        (status == nsEventStatus_eConsumeNoDefault);
+    MOZ_LOG_KEY_OR_IME(
+        LogLevel::Info,
+        ("%p   TextInputHandler::DoCommandBySelector, keypress event "
+         "dispatched, Destroyed()=%s, keypressHandled=%s",
+         this, TrueOrFalse(Destroyed()),
+         TrueOrFalse(currentKeyEvent->mKeyPressHandled)));
+    // This command is now dispatched with keypress event.
+    // So, this shouldn't be handled by nobody anymore.
+    return true;
+  }
+
+  // If the key operation didn't cause keypress event or caused keypress event
+  // but not prevented its default, we need to honor the command.  For example,
+  // Korean IME sends "insertNewline:" when committing existing composition
+  // with Enter key press.  In such case, the key operation has been consumed
+  // by the committing composition but we still need to handle the command.
+  if (Destroyed() || !currentKeyEvent->CanHandleCommand()) {
+    return true;
+  }
+
+  // cancelOperation: command is fired after Escape or Command + Period.
+  // However, if ChildView implements cancelOperation:, calling
+  // [[ChildView super] doCommandBySelector:aSelector] when Command + Period
+  // causes only a call of [ChildView cancelOperation:sender].  I.e.,
+  // [ChildView keyDown:theEvent] becomes to be never called.  For avoiding
+  // this odd behavior, we need to handle the command before super class of
+  // ChildView only when current key event is proper event to fire Escape
+  // keypress event.
+  if (!strcmp(aSelector, "cancelOperation:") && currentKeyEvent &&
+      currentKeyEvent->IsProperKeyEvent(Command::CancelOperation)) {
+    return HandleCommand(Command::CancelOperation);
+  }
+
+  // Otherwise, we've not handled the command yet.  Propagate the command
+  // to the super class of ChildView.
+  return false;
+}
+
+#pragma mark -
+
+/******************************************************************************
+ *
+ *  IMEInputHandler implementation (static methods)
+ *
+ ******************************************************************************/
+
+bool IMEInputHandler::sStaticMembersInitialized = false;
+bool IMEInputHandler::sCachedIsForRTLLangage = false;
+CFStringRef IMEInputHandler::sLatestIMEOpenedModeInputSourceID = nullptr;
+IMEInputHandler* IMEInputHandler::sFocusedIMEHandler = nullptr;
+
+// static
+void IMEInputHandler::InitStaticMembers() {
+  if (sStaticMembersInitialized) return;
+  sStaticMembersInitialized = true;
+  // We need to check the keyboard layout changes on all applications.
+  CFNotificationCenterRef center = ::CFNotificationCenterGetDistributedCenter();
+  // XXX Don't we need to remove the observer at shut down?
+  // Mac Dev Center's document doesn't say how to remove the observer if
+  // the second parameter is NULL.
+  ::CFNotificationCenterAddObserver(
+      center, NULL, OnCurrentTextInputSourceChange,
+      kTISNotifySelectedKeyboardInputSourceChanged, NULL,
+      CFNotificationSuspensionBehaviorDeliverImmediately);
+  // Initiailize with the current keyboard layout
+  OnCurrentTextInputSourceChange(
+      NULL, NULL, kTISNotifySelectedKeyboardInputSourceChanged, NULL, NULL);
+}
+
+// static
+void IMEInputHandler::OnCurrentTextInputSourceChange(
+    CFNotificationCenterRef aCenter, void* aObserver, CFStringRef aName,
+    const void* aObject, CFDictionaryRef aUserInfo) {
+  // Cache the latest IME opened mode to sLatestIMEOpenedModeInputSourceID.
+  TISInputSourceWrapper tis;
+  tis.InitByCurrentInputSource();
+  if (tis.IsOpenedIMEMode()) {
+    tis.GetInputSourceID(sLatestIMEOpenedModeInputSourceID);
+    // Collect Input Source ID which includes input mode in most cases.
+    // However, if it's Japanese IME, collecting input mode (e.g.,
+    // "HiraganaKotei") does not make sense because in most languages,
+    // input mode changes "how to input", but Japanese IME changes
+    // "which type of characters to input".  I.e., only Japanese IME
+    // users may use multiple input modes.  If we'd collect each type of
+    // input mode of Japanese IMEs, it'd be difficult to count actual
+    // users of each IME from the result.  So, only when active IME is
+    // a Japanese IME, we should use Bundle ID which does not contain
+    // input mode instead.
+    nsAutoString key;
+    if (tis.IsForJapaneseLanguage()) {
+      tis.GetBundleID(key);
+    } else {
+      tis.GetInputSourceID(key);
+    }
+    // 72 is kMaximumKeyStringLength in TelemetryScalar.cpp
+    if (key.Length() > 72) {
+      if (NS_IS_SURROGATE_PAIR(key[72 - 2], key[72 - 1])) {
+        key.Truncate(72 - 2);
+      } else {
+        key.Truncate(72 - 1);
+      }
+      // U+2026 is "..."
+      key.Append(char16_t(0x2026));
+    }
+    Telemetry::ScalarSet(Telemetry::ScalarID::WIDGET_IME_NAME_ON_MAC, key,
+                         true);
+  }
+
+  if (MOZ_LOG_TEST(gIMELog, LogLevel::Info)) {
+    static CFStringRef sLastTIS = nullptr;
+    CFStringRef newTIS;
+    tis.GetInputSourceID(newTIS);
+    if (!sLastTIS ||
+        ::CFStringCompare(sLastTIS, newTIS, 0) != kCFCompareEqualTo) {
+      TISInputSourceWrapper tis1, tis2, tis3, tis4, tis5;
+      tis1.InitByCurrentKeyboardLayout();
+      tis2.InitByCurrentASCIICapableInputSource();
+      tis3.InitByCurrentASCIICapableKeyboardLayout();
+      tis4.InitByCurrentInputMethodKeyboardLayoutOverride();
+      tis5.InitByTISInputSourceRef(tis.GetKeyboardLayoutInputSource());
+      CFStringRef is0 = nullptr, is1 = nullptr, is2 = nullptr, is3 = nullptr,
+                  is4 = nullptr, is5 = nullptr, type0 = nullptr,
+                  lang0 = nullptr, bundleID0 = nullptr;
+      tis.GetInputSourceID(is0);
+      tis1.GetInputSourceID(is1);
+      tis2.GetInputSourceID(is2);
+      tis3.GetInputSourceID(is3);
+      tis4.GetInputSourceID(is4);
+      tis5.GetInputSourceID(is5);
+      tis.GetInputSourceType(type0);
+      tis.GetPrimaryLanguage(lang0);
+      tis.GetBundleID(bundleID0);
+
+      MOZ_LOG(
+          gIMELog, LogLevel::Info,
+          ("IMEInputHandler::OnCurrentTextInputSourceChange,\n"
+           "  Current Input Source is changed to:\n"
+           "    currentInputContext=%p\n"
+           "    %s\n"
+           "      type=%s %s\n"
+           "      overridden keyboard layout=%s\n"
+           "      used keyboard layout for translation=%s\n"
+           "    primary language=%s\n"
+           "    bundle ID=%s\n"
+           "    current ASCII capable Input Source=%s\n"
+           "    current Keyboard Layout=%s\n"
+           "    current ASCII capable Keyboard Layout=%s",
+           [NSTextInputContext currentInputContext], GetCharacters(is0),
+           GetCharacters(type0), tis.IsASCIICapable() ? "- ASCII capable " : "",
+           GetCharacters(is4), GetCharacters(is5), GetCharacters(lang0),
+           GetCharacters(bundleID0), GetCharacters(is2), GetCharacters(is1),
+           GetCharacters(is3)));
+    }
+    sLastTIS = newTIS;
+  }
+
+  /**
+   * When the direction is changed, all the children are notified.
+   * No need to treat the initial case separately because it is covered
+   * by the general case (sCachedIsForRTLLangage is initially false)
+   */
+  if (sCachedIsForRTLLangage != tis.IsForRTLLanguage()) {
+    WidgetUtils::SendBidiKeyboardInfoToContent();
+    sCachedIsForRTLLangage = tis.IsForRTLLanguage();
+  }
+}
+
+// static
+void IMEInputHandler::FlushPendingMethods(nsITimer* aTimer, void* aClosure) {
+  NS_ASSERTION(aClosure, "aClosure is null");
+  static_cast<IMEInputHandler*>(aClosure)->ExecutePendingMethods();
+}
+
+// static
+CFArrayRef IMEInputHandler::CreateAllIMEModeList() {
+  const void* keys[] = {kTISPropertyInputSourceType};
+  const void* values[] = {kTISTypeKeyboardInputMode};
+  CFDictionaryRef filter =
+      ::CFDictionaryCreate(kCFAllocatorDefault, keys, values, 1, NULL, NULL);
+  NS_ASSERTION(filter, "failed to create the filter");
+  CFArrayRef list = ::TISCreateInputSourceList(filter, true);
+  ::CFRelease(filter);
+  return list;
+}
+
+// static
+void IMEInputHandler::DebugPrintAllIMEModes() {
+  if (MOZ_LOG_TEST(gIMELog, LogLevel::Info)) {
+    CFArrayRef list = CreateAllIMEModeList();
+    MOZ_LOG(gIMELog, LogLevel::Info, ("IME mode configuration:"));
+    CFIndex idx = ::CFArrayGetCount(list);
+    TISInputSourceWrapper tis;
+    for (CFIndex i = 0; i < idx; ++i) {
+      TISInputSourceRef inputSource = static_cast<TISInputSourceRef>(
+          const_cast<void*>(::CFArrayGetValueAtIndex(list, i)));
+      tis.InitByTISInputSourceRef(inputSource);
+      nsAutoString name, isid, bundleID;
+      tis.GetLocalizedName(name);
+      tis.GetInputSourceID(isid);
+      tis.GetBundleID(bundleID);
+      MOZ_LOG(
+          gIMELog, LogLevel::Info,
+          ("  %s\t<%s>%s%s\n"
+           "    bundled in <%s>\n",
+           NS_ConvertUTF16toUTF8(name).get(), NS_ConvertUTF16toUTF8(isid).get(),
+           tis.IsASCIICapable() ? "" : "\t(Isn't ASCII capable)",
+           tis.IsEnabled() ? "" : "\t(Isn't Enabled)",
+           NS_ConvertUTF16toUTF8(bundleID).get()));
+    }
+    ::CFRelease(list);
+  }
+}
+
+// static
+TSMDocumentID IMEInputHandler::GetCurrentTSMDocumentID() {
+  // At least on Mac OS X 10.6.x and 10.7.x, ::TSMGetActiveDocument() has a bug.
+  // The result of ::TSMGetActiveDocument() isn't modified for new active text
+  // input context until [NSTextInputContext currentInputContext] is called.
+  // Therefore, we need to call it here.
+  [NSTextInputContext currentInputContext];
+  return ::TSMGetActiveDocument();
+}
+
+#pragma mark -
+
+/******************************************************************************
+ *
+ *  IMEInputHandler implementation #1
+ *    The methods are releated to the pending methods.  Some jobs should be
+ *    run after the stack is finished, e.g, some methods cannot run the jobs
+ *    during processing the focus event.  And also some other jobs should be
+ *    run at the next focus event is processed.
+ *    The pending methods are recorded in mPendingMethods.  They are executed
+ *    by ExecutePendingMethods via FlushPendingMethods.
+ *
+ ******************************************************************************/
+
+nsresult IMEInputHandler::NotifyIME(TextEventDispatcher* aTextEventDispatcher,
+                                    const IMENotification& aNotification) {
+  switch (aNotification.mMessage) {
+    case REQUEST_TO_COMMIT_COMPOSITION:
+      CommitIMEComposition();
+      return NS_OK;
+    case REQUEST_TO_CANCEL_COMPOSITION:
+      CancelIMEComposition();
+      return NS_OK;
+    case NOTIFY_IME_OF_FOCUS:
+      if (IsFocused()) {
+        nsIWidget* widget = aTextEventDispatcher->GetWidget();
+        MOZ_LOG(gIMELog, LogLevel::Debug,
+                ("%p IMEInputHandler::NotifyIME(), IsFocused()=true, "
+                 "widget=%p, IsPasswordEditor()=%s",
+                 this, widget,
+                 TrueOrFalse(widget &&
+                             widget->GetInputContext().IsPasswordEditor())));
+        if (widget && widget->GetInputContext().IsPasswordEditor()) {
+          EnableSecureEventInput();
+        } else {
+          EnsureSecureEventInputDisabled();
+        }
+      } else if (MOZ_LOG_TEST(gIMELog, LogLevel::Debug)) {
+        NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+        NSWindow* window = mView ? [mView window] : nil;
+        MOZ_LOG(gIMELog, LogLevel::Debug,
+                ("%p IMEInputHandler::NotifyIME(), IsFocused()=false, "
+                 "Destroyed()=%s, mView=%p, "
+                 "[mView window]=%p, firstResponder=%p, isKeyWindow=%s, "
+                 "isActive=%s",
+                 this, TrueOrFalse(Destroyed()), mView, window,
+                 window ? [window firstResponder] : nil,
+                 TrueOrFalse(window && [window isKeyWindow]),
+                 TrueOrFalse([[NSApplication sharedApplication] isActive])));
+        NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE)
+      }
+      OnFocusChangeInGecko(true);
+      return NS_OK;
+    case NOTIFY_IME_OF_BLUR:
+      OnFocusChangeInGecko(false);
+      return NS_OK;
+    case NOTIFY_IME_OF_SELECTION_CHANGE:
+      OnSelectionChange(aNotification);
+      return NS_OK;
+    case NOTIFY_IME_OF_POSITION_CHANGE:
+      OnLayoutChange();
+      return NS_OK;
+    default:
+      return NS_ERROR_NOT_IMPLEMENTED;
+  }
+}
+
+NS_IMETHODIMP_(IMENotificationRequests)
+IMEInputHandler::GetIMENotificationRequests() {
+  // XXX Shouldn't we move floating window which shows composition string
+  //     when plugin has focus and its parent is scrolled or the window is
+  //     moved?
+  return IMENotificationRequests();
+}
+
+NS_IMETHODIMP_(void)
+IMEInputHandler::OnRemovedFrom(TextEventDispatcher* aTextEventDispatcher) {
+  // XXX When input transaction is being stolen by add-on, what should we do?
+}
+
+NS_IMETHODIMP_(void)
+IMEInputHandler::WillDispatchKeyboardEvent(
+    TextEventDispatcher* aTextEventDispatcher,
+    WidgetKeyboardEvent& aKeyboardEvent, uint32_t aIndexOfKeypress,
+    void* aData) {
+  // If the keyboard event is not caused by a native key event, we can do
+  // nothing here.
+  if (!aData) {
+    return;
+  }
+
+  KeyEventState* currentKeyEvent = static_cast<KeyEventState*>(aData);
+  NSEvent* nativeEvent = currentKeyEvent->mKeyEvent;
+  nsAString* insertString = currentKeyEvent->mInsertString;
+  if (aKeyboardEvent.mMessage == eKeyPress && aIndexOfKeypress == 0 &&
+      (!insertString || insertString->IsEmpty())) {
+    // Inform the child process that this is an event that we want a reply
+    // from.
+    // XXX This should be called only when the target is a remote process.
+    //     However, it's difficult to check it under widget/.
+    //     So, let's do this here for now, then,
+    //     EventStateManager::PreHandleEvent() will reset the flags if
+    //     the event target isn't in remote process.
+    aKeyboardEvent.MarkAsWaitingReplyFromRemoteProcess();
+  }
+  if (KeyboardLayoutOverrideRef().mOverrideEnabled) {
+    TISInputSourceWrapper tis;
+    tis.InitByLayoutID(KeyboardLayoutOverrideRef().mKeyboardLayout, true);
+    tis.WillDispatchKeyboardEvent(nativeEvent, insertString, aIndexOfKeypress,
+                                  aKeyboardEvent);
+  } else {
+    TISInputSourceWrapper::CurrentInputSource().WillDispatchKeyboardEvent(
+        nativeEvent, insertString, aIndexOfKeypress, aKeyboardEvent);
+  }
+
+  // Remove basic modifiers from keypress event because if they are included
+  // but this causes inputting text, since TextEditor won't handle eKeyPress
+  // events whose ctrlKey, altKey or metaKey is true as text input.
+  // Note that this hack should be used only when an editor has focus because
+  // this is a hack for TextEditor and modifier key information may be
+  // important for current web app.
+  if (IsEditableContent() && insertString &&
+      aKeyboardEvent.mMessage == eKeyPress && aKeyboardEvent.mCharCode) {
+    aKeyboardEvent.mModifiers &=
+        ~(MODIFIER_CONTROL | MODIFIER_ALT | MODIFIER_META);
+  }
+}
+
+void IMEInputHandler::NotifyIMEOfFocusChangeInGecko() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::NotifyIMEOfFocusChangeInGecko, "
+           "Destroyed()=%s, IsFocused()=%s, inputContext=%p",
+           this, TrueOrFalse(Destroyed()), TrueOrFalse(IsFocused()),
+           mView ? [mView inputContext] : nullptr));
+
+  if (Destroyed()) {
+    return;
+  }
+
+  if (!IsFocused()) {
+    // retry at next focus event
+    mPendingMethods |= kNotifyIMEOfFocusChangeInGecko;
+    return;
+  }
+
+  MOZ_ASSERT(mView);
+  NSTextInputContext* inputContext = [mView inputContext];
+  NS_ENSURE_TRUE_VOID(inputContext);
+
+  // When an <input> element on a XUL <panel> element gets focus from an <input>
+  // element on the opener window of the <panel> element, the owner window
+  // still has native focus.  Therefore, IMEs may store the opener window's
+  // level at this time because they don't know the actual focus is moved to
+  // different window.  If IMEs try to get the newest window level after the
+  // focus change, we return the window level of the XUL <panel>'s widget.
+  // Therefore, let's emulate the native focus change.  Then, IMEs can refresh
+  // the stored window level.
+  [inputContext deactivate];
+  [inputContext activate];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void IMEInputHandler::SyncASCIICapableOnly() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::SyncASCIICapableOnly, "
+           "Destroyed()=%s, IsFocused()=%s, mIsASCIICapableOnly=%s, "
+           "GetCurrentTSMDocumentID()=%p",
+           this, TrueOrFalse(Destroyed()), TrueOrFalse(IsFocused()),
+           TrueOrFalse(mIsASCIICapableOnly), GetCurrentTSMDocumentID()));
+
+  if (Destroyed()) {
+    return;
+  }
+
+  if (!IsFocused()) {
+    // retry at next focus event
+    mPendingMethods |= kSyncASCIICapableOnly;
+    return;
+  }
+
+  TSMDocumentID doc = GetCurrentTSMDocumentID();
+  if (!doc) {
+    // retry
+    mPendingMethods |= kSyncASCIICapableOnly;
+    NS_WARNING("Application is active but there is no active document");
+    ResetTimer();
+    return;
+  }
+
+  if (mIsASCIICapableOnly) {
+    CFArrayRef ASCIICapableTISList = ::TISCreateASCIICapableInputSourceList();
+    ::TSMSetDocumentProperty(doc, kTSMDocumentEnabledInputSourcesPropertyTag,
+                             sizeof(CFArrayRef), &ASCIICapableTISList);
+    ::CFRelease(ASCIICapableTISList);
+  } else {
+    ::TSMRemoveDocumentProperty(doc,
+                                kTSMDocumentEnabledInputSourcesPropertyTag);
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void IMEInputHandler::ResetTimer() {
+  NS_ASSERTION(mPendingMethods != 0,
+               "There are not pending methods, why this is called?");
+  if (mTimer) {
+    mTimer->Cancel();
+  } else {
+    mTimer = NS_NewTimer();
+    NS_ENSURE_TRUE(mTimer, );
+  }
+  mTimer->InitWithNamedFuncCallback(FlushPendingMethods, this, 0,
+                                    nsITimer::TYPE_ONE_SHOT,
+                                    "IMEInputHandler::FlushPendingMethods");
+}
+
+void IMEInputHandler::ExecutePendingMethods() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mTimer) {
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
+
+  if (![[NSApplication sharedApplication] isActive]) {
+    // If we're not active, we should retry at focus event
+    return;
+  }
+
+  uint32_t pendingMethods = mPendingMethods;
+  // First, reset the pending method flags because if each methods cannot
+  // run now, they can reentry to the pending flags by theirselves.
+  mPendingMethods = 0;
+
+  if (pendingMethods & kSyncASCIICapableOnly) SyncASCIICapableOnly();
+  if (pendingMethods & kNotifyIMEOfFocusChangeInGecko) {
+    NotifyIMEOfFocusChangeInGecko();
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+#pragma mark -
+
+/******************************************************************************
+ *
+ * IMEInputHandler implementation (native event handlers)
+ *
+ ******************************************************************************/
+
+TextRangeType IMEInputHandler::ConvertToTextRangeType(uint32_t aUnderlineStyle,
+                                                      NSRange& aSelectedRange) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::ConvertToTextRangeType, "
+           "aUnderlineStyle=%u, aSelectedRange.length=%lu,",
+           this, aUnderlineStyle,
+           static_cast<unsigned long>(aSelectedRange.length)));
+
+  // We assume that aUnderlineStyle is NSUnderlineStyleSingle or
+  // NSUnderlineStyleThick.  NSUnderlineStyleThick should indicate a selected
+  // clause.  Otherwise, should indicate non-selected clause.
+
+  if (aSelectedRange.length == 0) {
+    switch (aUnderlineStyle) {
+      case NSUnderlineStyleSingle:
+        return TextRangeType::eRawClause;
+      case NSUnderlineStyleThick:
+        return TextRangeType::eSelectedRawClause;
+      default:
+        NS_WARNING("Unexpected line style");
+        return TextRangeType::eSelectedRawClause;
+    }
+  }
+
+  switch (aUnderlineStyle) {
+    case NSUnderlineStyleSingle:
+      return TextRangeType::eConvertedClause;
+    case NSUnderlineStyleThick:
+      return TextRangeType::eSelectedClause;
+    default:
+      NS_WARNING("Unexpected line style");
+      return TextRangeType::eSelectedClause;
+  }
+}
+
+uint32_t IMEInputHandler::GetRangeCount(NSAttributedString* aAttrString) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // Iterate through aAttrString for the NSUnderlineStyleAttributeName and
+  // count the different segments adjusting limitRange as we go.
+  uint32_t count = 0;
+  NSRange effectiveRange;
+  NSRange limitRange = NSMakeRange(0, [aAttrString length]);
+  while (limitRange.length > 0) {
+    [aAttrString attribute:NSUnderlineStyleAttributeName
+                      atIndex:limitRange.location
+        longestEffectiveRange:&effectiveRange
+                      inRange:limitRange];
+    limitRange =
+        NSMakeRange(NSMaxRange(effectiveRange),
+                    NSMaxRange(limitRange) - NSMaxRange(effectiveRange));
+    count++;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::GetRangeCount, aAttrString=\"%s\", count=%u",
+           this, GetCharacters([aAttrString string]), count));
+
+  return count;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(0);
+}
+
+already_AddRefed<mozilla::TextRangeArray> IMEInputHandler::CreateTextRangeArray(
+    NSAttributedString* aAttrString, NSRange& aSelectedRange) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  RefPtr<mozilla::TextRangeArray> textRangeArray =
+      new mozilla::TextRangeArray();
+
+  // Note that we shouldn't append ranges when composition string
+  // is empty because it may cause TextComposition confused.
+  if (![aAttrString length]) {
+    return textRangeArray.forget();
+  }
+
+  // Convert the Cocoa range into the TextRange Array used in Gecko.
+  // Iterate through the attributed string and map the underline attribute to
+  // Gecko IME textrange attributes.  We may need to change the code here if
+  // we change the implementation of validAttributesForMarkedText.
+  NSRange limitRange = NSMakeRange(0, [aAttrString length]);
+  uint32_t rangeCount = GetRangeCount(aAttrString);
+  for (uint32_t i = 0; i < rangeCount && limitRange.length > 0; i++) {
+    NSRange effectiveRange;
+    id attributeValue = [aAttrString attribute:NSUnderlineStyleAttributeName
+                                       atIndex:limitRange.location
+                         longestEffectiveRange:&effectiveRange
+                                       inRange:limitRange];
+
+    TextRange range;
+    range.mStartOffset = effectiveRange.location;
+    range.mEndOffset = NSMaxRange(effectiveRange);
+    range.mRangeType =
+        ConvertToTextRangeType([attributeValue intValue], aSelectedRange);
+    textRangeArray->AppendElement(range);
+
+    MOZ_LOG(
+        gIMELog, LogLevel::Info,
+        ("%p   IMEInputHandler::CreateTextRangeArray, "
+         "range={ mStartOffset=%u, mEndOffset=%u, mRangeType=%s }",
+         this, range.mStartOffset, range.mEndOffset, ToChar(range.mRangeType)));
+
+    limitRange =
+        NSMakeRange(NSMaxRange(effectiveRange),
+                    NSMaxRange(limitRange) - NSMaxRange(effectiveRange));
+  }
+
+  // Get current caret position.
+  TextRange range;
+  range.mStartOffset = aSelectedRange.location + aSelectedRange.length;
+  range.mEndOffset = range.mStartOffset;
+  range.mRangeType = TextRangeType::eCaret;
+  textRangeArray->AppendElement(range);
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("%p IMEInputHandler::CreateTextRangeArray, "
+       "range={ mStartOffset=%u, mEndOffset=%u, mRangeType=%s }",
+       this, range.mStartOffset, range.mEndOffset, ToChar(range.mRangeType)));
+
+  return textRangeArray.forget();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nullptr);
+}
+
+bool IMEInputHandler::DispatchCompositionStartEvent() {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("%p IMEInputHandler::DispatchCompositionStartEvent, "
+       "mSelectedRange={ location=%lu, length=%lu }, Destroyed()=%s, "
+       "mView=%p, mWidget=%p, inputContext=%p, mIsIMEComposing=%s",
+       this, static_cast<unsigned long>(SelectedRange().location),
+       static_cast<unsigned long>(mSelectedRange.length),
+       TrueOrFalse(Destroyed()), mView, mWidget,
+       mView ? [mView inputContext] : nullptr, TrueOrFalse(mIsIMEComposing)));
+
+  RefPtr<IMEInputHandler> kungFuDeathGrip(this);
+
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("%p   IMEInputHandler::DispatchCompositionStartEvent, "
+             "FAILED, due to BeginNativeInputTransaction() failure",
+             this));
+    return false;
+  }
+
+  NS_ASSERTION(!mIsIMEComposing, "There is a composition already");
+  mIsIMEComposing = true;
+  KeyEventState* currentKeyEvent = GetCurrentKeyEvent();
+  mIsDeadKeyComposing = currentKeyEvent && currentKeyEvent->mKeyEvent &&
+                        TISInputSourceWrapper::CurrentInputSource().IsDeadKey(
+                            currentKeyEvent->mKeyEvent);
+
+  nsEventStatus status;
+  rv = mDispatcher->StartComposition(status);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("%p   IMEInputHandler::DispatchCompositionStartEvent, "
+             "FAILED, due to StartComposition() failure",
+             this));
+    return false;
+  }
+
+  if (Destroyed()) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("%p   IMEInputHandler::DispatchCompositionStartEvent, "
+             "destroyed by compositionstart event",
+             this));
+    return false;
+  }
+
+  // FYI: compositionstart may cause committing composition by the webapp.
+  if (!mIsIMEComposing) {
+    return false;
+  }
+
+  // FYI: The selection range might have been modified by a compositionstart
+  //      event handler.
+  mIMECompositionStart = SelectedRange().location;
+  return true;
+}
+
+bool IMEInputHandler::DispatchCompositionChangeEvent(
+    const nsString& aText, NSAttributedString* aAttrString,
+    NSRange& aSelectedRange) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("%p IMEInputHandler::DispatchCompositionChangeEvent, "
+       "aText=\"%s\", aAttrString=\"%s\", "
+       "aSelectedRange={ location=%lu, length=%lu }, Destroyed()=%s, mView=%p, "
+       "mWidget=%p, inputContext=%p, mIsIMEComposing=%s",
+       this, NS_ConvertUTF16toUTF8(aText).get(),
+       GetCharacters([aAttrString string]),
+       static_cast<unsigned long>(aSelectedRange.location),
+       static_cast<unsigned long>(aSelectedRange.length),
+       TrueOrFalse(Destroyed()), mView, mWidget,
+       mView ? [mView inputContext] : nullptr, TrueOrFalse(mIsIMEComposing)));
+
+  NS_ENSURE_TRUE(!Destroyed(), false);
+
+  NS_ASSERTION(mIsIMEComposing, "We're not in composition");
+
+  RefPtr<IMEInputHandler> kungFuDeathGrip(this);
+
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("%p   IMEInputHandler::DispatchCompositionChangeEvent, "
+             "FAILED, due to BeginNativeInputTransaction() failure",
+             this));
+    return false;
+  }
+
+  RefPtr<TextRangeArray> rangeArray =
+      CreateTextRangeArray(aAttrString, aSelectedRange);
+
+  rv = mDispatcher->SetPendingComposition(aText, rangeArray);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("%p   IMEInputHandler::DispatchCompositionChangeEvent, "
+             "FAILED, due to SetPendingComposition() failure",
+             this));
+    return false;
+  }
+
+  mSelectedRange.location = mIMECompositionStart + aSelectedRange.location;
+  mSelectedRange.length = aSelectedRange.length;
+
+  if (mIMECompositionString) {
+    [mIMECompositionString release];
+  }
+  mIMECompositionString = [[aAttrString string] retain];
+
+  nsEventStatus status;
+  rv = mDispatcher->FlushPendingComposition(status);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("%p   IMEInputHandler::DispatchCompositionChangeEvent, "
+             "FAILED, due to FlushPendingComposition() failure",
+             this));
+    return false;
+  }
+
+  if (Destroyed()) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("%p   IMEInputHandler::DispatchCompositionChangeEvent, "
+             "destroyed by compositionchange event",
+             this));
+    return false;
+  }
+
+  // FYI: compositionstart may cause committing composition by the webapp.
+  return mIsIMEComposing;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
+
+bool IMEInputHandler::DispatchCompositionCommitEvent(
+    const nsAString* aCommitString) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("%p IMEInputHandler::DispatchCompositionCommitEvent, "
+       "aCommitString=0x%p (\"%s\"), Destroyed()=%s, mView=%p, mWidget=%p, "
+       "inputContext=%p, mIsIMEComposing=%s",
+       this, aCommitString,
+       aCommitString ? NS_ConvertUTF16toUTF8(*aCommitString).get() : "",
+       TrueOrFalse(Destroyed()), mView, mWidget,
+       mView ? [mView inputContext] : nullptr, TrueOrFalse(mIsIMEComposing)));
+
+  NS_ASSERTION(mIsIMEComposing, "We're not in composition");
+
+  RefPtr<IMEInputHandler> kungFuDeathGrip(this);
+
+  if (!Destroyed()) {
+    // IME may query selection immediately after this, however, in e10s mode,
+    // OnSelectionChange() will be called asynchronously.  Until then, we
+    // should emulate expected selection range if the webapp does nothing.
+    mSelectedRange.location = mIMECompositionStart;
+    if (aCommitString) {
+      mSelectedRange.location += aCommitString->Length();
+    } else if (mIMECompositionString) {
+      nsAutoString commitString;
+      nsCocoaUtils::GetStringForNSString(mIMECompositionString, commitString);
+      mSelectedRange.location += commitString.Length();
+    }
+    mSelectedRange.length = 0;
+
+    nsresult rv = mDispatcher->BeginNativeInputTransaction();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("%p   IMEInputHandler::DispatchCompositionCommitEvent, "
+               "FAILED, due to BeginNativeInputTransaction() failure",
+               this));
+    } else {
+      nsEventStatus status;
+      rv = mDispatcher->CommitComposition(status, aCommitString);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        MOZ_LOG(gIMELog, LogLevel::Error,
+                ("%p   IMEInputHandler::DispatchCompositionCommitEvent, "
+                 "FAILED, due to BeginNativeInputTransaction() failure",
+                 this));
+      }
+    }
+  }
+
+  mIsIMEComposing = mIsDeadKeyComposing = false;
+  mIMECompositionStart = UINT32_MAX;
+  if (mIMECompositionString) {
+    [mIMECompositionString release];
+    mIMECompositionString = nullptr;
+  }
+
+  if (Destroyed()) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("%p   IMEInputHandler::DispatchCompositionCommitEvent, "
+             "destroyed by compositioncommit event",
+             this));
+    return false;
+  }
+
+  return true;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
+
+bool IMEInputHandler::MaybeDispatchCurrentKeydownEvent(bool aIsProcessedByIME) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (Destroyed()) {
+    return false;
+  }
+  MOZ_ASSERT(mWidget);
+
+  KeyEventState* currentKeyEvent = GetCurrentKeyEvent();
+  if (!currentKeyEvent || !currentKeyEvent->CanDispatchKeyDownEvent()) {
+    return true;
+  }
+
+  NSEvent* nativeEvent = currentKeyEvent->mKeyEvent;
+  if (NS_WARN_IF(!nativeEvent) || [nativeEvent type] != NSEventTypeKeyDown) {
+    return true;
+  }
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("%p IMEInputHandler::MaybeDispatchKeydownEvent, aIsProcessedByIME=%s "
+       "currentKeyEvent={ mKeyEvent(%p)={ type=%s, keyCode=%s (0x%X) } }, "
+       "aIsProcessedBy=%s, IsDeadKeyComposing()=%s",
+       this, TrueOrFalse(aIsProcessedByIME), nativeEvent,
+       GetNativeKeyEventType(nativeEvent),
+       GetKeyNameForNativeKeyCode([nativeEvent keyCode]), [nativeEvent keyCode],
+       TrueOrFalse(IsIMEComposing()), TrueOrFalse(IsDeadKeyComposing())));
+
+  RefPtr<IMEInputHandler> kungFuDeathGrip(this);
+  RefPtr<TextEventDispatcher> dispatcher(mDispatcher);
+  nsresult rv = dispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("%p   IMEInputHandler::DispatchKeyEventForFlagsChanged, "
+             "FAILED, due to BeginNativeInputTransaction() failure",
+             this));
+    return false;
+  }
+
+  NSResponder* firstResponder = [[mView window] firstResponder];
+
+  // Mark currentKeyEvent as "dispatched eKeyDown event" and actually do it.
+  currentKeyEvent->mKeyDownDispatched = true;
+
+  RefPtr<nsChildView> widget(mWidget);
+
+  WidgetKeyboardEvent keydownEvent(true, eKeyDown, widget);
+  // Don't mark the eKeyDown event as "processed by IME" if the composition
+  // is started with dead key.
+  currentKeyEvent->InitKeyEvent(this, keydownEvent,
+                                aIsProcessedByIME && !IsDeadKeyComposing());
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  dispatcher->DispatchKeyboardEvent(eKeyDown, keydownEvent, status,
+                                    currentKeyEvent);
+  currentKeyEvent->mKeyDownHandled =
+      (status == nsEventStatus_eConsumeNoDefault);
+
+  if (Destroyed()) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("%p   IMEInputHandler::MaybeDispatchKeydownEvent, "
+             "widget was destroyed by keydown event",
+             this));
+    return false;
+  }
+
+  // The key down event may have shifted the focus, in which case, we should
+  // not continue to handle current key sequence and let's commit current
+  // composition.
+  if (firstResponder != [[mView window] firstResponder]) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("%p   IMEInputHandler::MaybeDispatchKeydownEvent, "
+             "view lost focus by keydown event",
+             this));
+    CommitIMEComposition();
+    return false;
+  }
+
+  return true;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
+
+void IMEInputHandler::InsertTextAsCommittingComposition(
+    NSString* aString, NSRange* aReplacementRange) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("%p IMEInputHandler::InsertTextAsCommittingComposition, "
+       "aAttrString=\"%s\", aReplacementRange=%p { location=%lu, length=%lu }, "
+       "Destroyed()=%s, IsIMEComposing()=%s, "
+       "mMarkedRange={ location=%lu, length=%lu }",
+       this, GetCharacters(aString), aReplacementRange,
+       static_cast<unsigned long>(
+           aReplacementRange ? aReplacementRange->location : 0),
+       static_cast<unsigned long>(aReplacementRange ? aReplacementRange->length
+                                                    : 0),
+       TrueOrFalse(Destroyed()), TrueOrFalse(IsIMEComposing()),
+       static_cast<unsigned long>(mMarkedRange.location),
+       static_cast<unsigned long>(mMarkedRange.length)));
+
+  if (IgnoreIMECommit()) {
+    MOZ_CRASH("IMEInputHandler::InsertTextAsCommittingComposition() must not"
+              "be called while canceling the composition");
+  }
+
+  if (Destroyed()) {
+    return;
+  }
+
+  // When current keydown event causes this text input, let's dispatch
+  // eKeyDown event before any other events.  Note that if we're in a
+  // composition, we've already dispatched eKeyDown event from
+  // TextInputHandler::HandleKeyDownEvent().
+  // XXX Should we mark the eKeyDown event as "processed by IME"?
+  //     However, if the key causes two or more Unicode characters as
+  //     UTF-16 string, this is used.  So, perhaps, we need to improve
+  //     HandleKeyDownEvent() before do that.
+  RefPtr<IMEInputHandler> kungFuDeathGrip(this);
+  if (!IsIMEComposing() && !MaybeDispatchCurrentKeydownEvent(false)) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Info,
+        ("%p   IMEInputHandler::InsertTextAsCommittingComposition, eKeyDown "
+         "caused focus move or something and canceling the composition",
+         this));
+    return;
+  }
+
+  // First, commit current composition with the latest composition string if the
+  // replacement range is different from marked range.
+  if (IsIMEComposing() && aReplacementRange &&
+      aReplacementRange->location != NSNotFound &&
+      !NSEqualRanges(MarkedRange(), *aReplacementRange)) {
+    if (!DispatchCompositionCommitEvent()) {
+      MOZ_LOG(
+          gIMELog, LogLevel::Info,
+          ("%p   IMEInputHandler::InsertTextAsCommittingComposition, "
+           "destroyed by commiting composition for setting replacement range",
+           this));
+      return;
+    }
+  }
+
+  nsString str;
+  nsCocoaUtils::GetStringForNSString(aString, str);
+
+  if (!IsIMEComposing()) {
+    MOZ_DIAGNOSTIC_ASSERT(!str.IsEmpty());
+
+    // If there is no selection and replacement range is specified, set the
+    // range as selection.
+    if (aReplacementRange && aReplacementRange->location != NSNotFound &&
+        !NSEqualRanges(SelectedRange(), *aReplacementRange)) {
+      NS_ENSURE_TRUE_VOID(SetSelection(*aReplacementRange));
+    }
+
+    if (!StaticPrefs::intl_ime_use_composition_events_for_insert_text()) {
+      // In the default settings, we should not use composition events for
+      // inserting text without key press nor IME composition because the
+      // other browsers do so.   This will cause only a cancelable `beforeinput`
+      // event whose `inputType` is `insertText`.
+      WidgetContentCommandEvent insertTextEvent(true, eContentCommandInsertText,
+                                                mWidget);
+      insertTextEvent.mString = Some(str);
+      DispatchEvent(insertTextEvent);
+      return;
+    }
+
+    // Otherise, emulate an IME composition.  This is our traditional behavior,
+    // but `beforeinput` events are not cancelable since they should be so for
+    // native IME limitation.  So, this is now seriously imcompatible with the
+    // other browsers.
+    if (!DispatchCompositionStartEvent()) {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("%p   IMEInputHandler::InsertTextAsCommittingComposition, "
+               "cannot continue handling composition after compositionstart",
+               this));
+      return;
+    }
+  }
+
+  if (!DispatchCompositionCommitEvent(&str)) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("%p   IMEInputHandler::InsertTextAsCommittingComposition, "
+             "destroyed by compositioncommit event",
+             this));
+    return;
+  }
+
+  mMarkedRange = NSMakeRange(NSNotFound, 0);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void IMEInputHandler::SetMarkedText(NSAttributedString* aAttrString,
+                                    NSRange& aSelectedRange,
+                                    NSRange* aReplacementRange) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  KeyEventState* currentKeyEvent = GetCurrentKeyEvent();
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("%p IMEInputHandler::SetMarkedText, "
+       "aAttrString=\"%s\", aSelectedRange={ location=%lu, length=%lu }, "
+       "aReplacementRange=%p { location=%lu, length=%lu }, "
+       "Destroyed()=%s, IsIMEComposing()=%s, "
+       "mMarkedRange={ location=%lu, length=%lu }, keyevent=%p, "
+       "keydownDispatched=%s, keydownHandled=%s, "
+       "keypressDispatched=%s, causedOtherKeyEvents=%s, "
+       "compositionDispatched=%s",
+       this, GetCharacters([aAttrString string]),
+       static_cast<unsigned long>(aSelectedRange.location),
+       static_cast<unsigned long>(aSelectedRange.length), aReplacementRange,
+       static_cast<unsigned long>(
+           aReplacementRange ? aReplacementRange->location : 0),
+       static_cast<unsigned long>(aReplacementRange ? aReplacementRange->length
+                                                    : 0),
+       TrueOrFalse(Destroyed()), TrueOrFalse(IsIMEComposing()),
+       static_cast<unsigned long>(mMarkedRange.location),
+       static_cast<unsigned long>(mMarkedRange.length),
+       currentKeyEvent ? currentKeyEvent->mKeyEvent : nullptr,
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyDownDispatched)
+                       : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyDownHandled) : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mKeyPressDispatched)
+                       : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mCausedOtherKeyEvents)
+                       : "N/A",
+       currentKeyEvent ? TrueOrFalse(currentKeyEvent->mCompositionDispatched)
+                       : "N/A"));
+
+  RefPtr<IMEInputHandler> kungFuDeathGrip(this);
+
+  // If SetMarkedText() is called during handling a key press, that means that
+  // the key event caused this composition.  So, keypress event shouldn't
+  // be dispatched later, let's mark the key event causing composition event.
+  if (currentKeyEvent) {
+    currentKeyEvent->mCompositionDispatched = true;
+
+    // When current keydown event causes this text input, let's dispatch
+    // eKeyDown event before any other events.  Note that if we're in a
+    // composition, we've already dispatched eKeyDown event from
+    // TextInputHandler::HandleKeyDownEvent().  On the other hand, if we're
+    // not in composition, the key event starts new composition.  So, we
+    // need to mark the eKeyDown event as "processed by IME".
+    if (!IsIMEComposing() && !MaybeDispatchCurrentKeydownEvent(true)) {
+      MOZ_LOG(
+          gIMELog, LogLevel::Info,
+          ("%p   IMEInputHandler::SetMarkedText, eKeyDown caused focus move or "
+           "something and canceling the composition",
+           this));
+      return;
+    }
+  }
+
+  if (Destroyed()) {
+    return;
+  }
+
+  // First, commit current composition with the latest composition string if the
+  // replacement range is different from marked range.
+  if (IsIMEComposing() && aReplacementRange &&
+      aReplacementRange->location != NSNotFound &&
+      !NSEqualRanges(MarkedRange(), *aReplacementRange)) {
+    AutoRestore<bool> ignoreIMECommit(mIgnoreIMECommit);
+    mIgnoreIMECommit = false;
+    if (!DispatchCompositionCommitEvent()) {
+      MOZ_LOG(
+          gIMELog, LogLevel::Info,
+          ("%p   IMEInputHandler::SetMarkedText, "
+           "destroyed by commiting composition for setting replacement range",
+           this));
+      return;
+    }
+  }
+
+  nsString str;
+  nsCocoaUtils::GetStringForNSString([aAttrString string], str);
+
+  mMarkedRange.length = str.Length();
+
+  if (!IsIMEComposing() && !str.IsEmpty()) {
+    // If there is no selection and replacement range is specified, set the
+    // range as selection.
+    if (aReplacementRange && aReplacementRange->location != NSNotFound &&
+        !NSEqualRanges(SelectedRange(), *aReplacementRange)) {
+      // Set temporary selection range since OnSelectionChange is async.
+      mSelectedRange = *aReplacementRange;
+      if (NS_WARN_IF(!SetSelection(*aReplacementRange))) {
+        mSelectedRange.location = NSNotFound;  // Marking dirty
+        return;
+      }
+    }
+
+    mMarkedRange.location = SelectedRange().location;
+
+    if (!DispatchCompositionStartEvent()) {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("%p   IMEInputHandler::SetMarkedText, cannot continue handling "
+               "composition after dispatching compositionstart",
+               this));
+      return;
+    }
+  }
+
+  if (!str.IsEmpty()) {
+    if (!DispatchCompositionChangeEvent(str, aAttrString, aSelectedRange)) {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("%p   IMEInputHandler::SetMarkedText, cannot continue handling "
+               "composition after dispatching compositionchange",
+               this));
+    }
+    return;
+  }
+
+  // If the composition string becomes empty string, we should commit
+  // current composition.
+  if (!DispatchCompositionCommitEvent(&EmptyString())) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("%p   IMEInputHandler::SetMarkedText, "
+             "destroyed by compositioncommit event",
+             this));
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+NSAttributedString* IMEInputHandler::GetAttributedSubstringFromRange(
+    NSRange& aRange, NSRange* aActualRange) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("%p   IMEInputHandler::GetAttributedSubstringFromRange, "
+       "aRange={ location=%lu, length=%lu }, aActualRange=%p, Destroyed()=%s",
+       this, static_cast<unsigned long>(aRange.location),
+       static_cast<unsigned long>(aRange.length), aActualRange,
+       TrueOrFalse(Destroyed())));
+
+  if (aActualRange) {
+    *aActualRange = NSMakeRange(NSNotFound, 0);
+  }
+
+  if (Destroyed() || aRange.location == NSNotFound || aRange.length == 0) {
+    return nil;
+  }
+
+  RefPtr<IMEInputHandler> kungFuDeathGrip(this);
+
+  // If we're in composing, the queried range may be in the composition string.
+  // In such case, we should use mIMECompositionString since if the composition
+  // string is handled by a remote process, the content cache may be out of
+  // date.
+  // XXX Should we set composition string attributes?  Although, Blink claims
+  //     that some attributes of marked text are supported, but they return
+  //     just marked string without any style.  So, let's keep current behavior
+  //     at least for now.
+  NSUInteger compositionLength =
+      mIMECompositionString ? [mIMECompositionString length] : 0;
+  if (mIMECompositionStart != UINT32_MAX &&
+      aRange.location >= mIMECompositionStart &&
+      aRange.location + aRange.length <=
+          mIMECompositionStart + compositionLength) {
+    NSRange range =
+        NSMakeRange(aRange.location - mIMECompositionStart, aRange.length);
+    NSString* nsstr = [mIMECompositionString substringWithRange:range];
+    NSMutableAttributedString* result =
+        [[[NSMutableAttributedString alloc] initWithString:nsstr
+                                                attributes:nil] autorelease];
+    // XXX We cannot return font information in this case.  However, this
+    //     case must occur only when IME tries to confirm if composing string
+    //     is handled as expected.
+    if (aActualRange) {
+      *aActualRange = aRange;
+    }
+
+    if (MOZ_LOG_TEST(gIMELog, LogLevel::Info)) {
+      nsAutoString str;
+      nsCocoaUtils::GetStringForNSString(nsstr, str);
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("%p   IMEInputHandler::GetAttributedSubstringFromRange, "
+               "computed with mIMECompositionString (result string=\"%s\")",
+               this, NS_ConvertUTF16toUTF8(str).get()));
+    }
+    return result;
+  }
+
+  nsAutoString str;
+  WidgetQueryContentEvent queryTextContentEvent(true, eQueryTextContent,
+                                                mWidget);
+  WidgetQueryContentEvent::Options options;
+  int64_t startOffset = aRange.location;
+  if (IsIMEComposing()) {
+    // The composition may be at different offset from the selection start
+    // offset at dispatching compositionstart because start of composition
+    // is fixed when composition string becomes non-empty in the editor.
+    // Therefore, we need to use query event which is relative to insertion
+    // point.
+    options.mRelativeToInsertionPoint = true;
+    startOffset -= mIMECompositionStart;
+  }
+  queryTextContentEvent.InitForQueryTextContent(startOffset, aRange.length,
+                                                options);
+  queryTextContentEvent.RequestFontRanges();
+  DispatchEvent(queryTextContentEvent);
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p   IMEInputHandler::GetAttributedSubstringFromRange, "
+           "queryTextContentEvent={ mReply=%s }",
+           this, ToString(queryTextContentEvent.mReply).c_str()));
+
+  if (queryTextContentEvent.Failed()) {
+    return nil;
+  }
+
+  // We don't set vertical information at this point.  If required,
+  // OS will calls drawsVerticallyForCharacterAtIndex.
+  NSMutableAttributedString* result =
+      nsCocoaUtils::GetNSMutableAttributedString(
+          queryTextContentEvent.mReply->DataRef(),
+          queryTextContentEvent.mReply->mFontRanges, false,
+          mWidget->BackingScaleFactor());
+  if (aActualRange) {
+    *aActualRange =
+        MakeNSRangeFrom(queryTextContentEvent.mReply->mOffsetAndData);
+  }
+  return result;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+bool IMEInputHandler::HasMarkedText() {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p   IMEInputHandler::HasMarkedText, "
+           "mMarkedRange={ location=%lu, length=%lu }",
+           this, static_cast<unsigned long>(mMarkedRange.location),
+           static_cast<unsigned long>(mMarkedRange.length)));
+
+  return (mMarkedRange.location != NSNotFound) && (mMarkedRange.length != 0);
+}
+
+NSRange IMEInputHandler::MarkedRange() {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p   IMEInputHandler::MarkedRange, "
+           "mMarkedRange={ location=%lu, length=%lu }",
+           this, static_cast<unsigned long>(mMarkedRange.location),
+           static_cast<unsigned long>(mMarkedRange.length)));
+
+  if (!HasMarkedText()) {
+    return NSMakeRange(NSNotFound, 0);
+  }
+  return mMarkedRange;
+}
+
+NSRange IMEInputHandler::SelectedRange() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("%p   IMEInputHandler::SelectedRange, Destroyed()=%s, mSelectedRange={ "
+       "location=%lu, length=%lu }",
+       this, TrueOrFalse(Destroyed()),
+       static_cast<unsigned long>(mSelectedRange.location),
+       static_cast<unsigned long>(mSelectedRange.length)));
+
+  if (Destroyed()) {
+    return mSelectedRange;
+  }
+
+  if (mSelectedRange.location != NSNotFound) {
+    MOZ_ASSERT(mIMEHasFocus);
+    return mSelectedRange;
+  }
+
+  RefPtr<IMEInputHandler> kungFuDeathGrip(this);
+
+  WidgetQueryContentEvent querySelectedTextEvent(true, eQuerySelectedText,
+                                                 mWidget);
+  DispatchEvent(querySelectedTextEvent);
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p   IMEInputHandler::SelectedRange, querySelectedTextEvent={ "
+           "mReply=%s }",
+           this, ToString(querySelectedTextEvent.mReply).c_str()));
+
+  if (querySelectedTextEvent.Failed()) {
+    return mSelectedRange;
+  }
+
+  mWritingMode = querySelectedTextEvent.mReply->WritingModeRef();
+  mRangeForWritingMode =
+      MakeNSRangeFrom(querySelectedTextEvent.mReply->mOffsetAndData);
+
+  if (mIMEHasFocus) {
+    mSelectedRange = mRangeForWritingMode;
+  }
+
+  return mRangeForWritingMode;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(mSelectedRange);
+}
+
+bool IMEInputHandler::DrawsVerticallyForCharacterAtIndex(uint32_t aCharIndex) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (Destroyed()) {
+    return false;
+  }
+
+  if (mRangeForWritingMode.location == NSNotFound) {
+    // Update cached writing-mode value for the current selection.
+    SelectedRange();
+  }
+
+  if (aCharIndex < mRangeForWritingMode.location ||
+      aCharIndex >
+          mRangeForWritingMode.location + mRangeForWritingMode.length) {
+    // It's not clear to me whether this ever happens in practice, but if an
+    // IME ever wants to query writing mode at an offset outside the current
+    // selection, the writing-mode value may not be correct for the index.
+    // In that case, use FirstRectForCharacterRange to get a fresh value.
+    // This does more work than strictly necessary (we don't need the rect
+    // here), but should be a rare case.
+    NS_WARNING(
+        "DrawsVerticallyForCharacterAtIndex not using cached writing mode");
+    NSRange range = NSMakeRange(aCharIndex, 1);
+    NSRange actualRange;
+    FirstRectForCharacterRange(range, &actualRange);
+  }
+
+  return mWritingMode.IsVertical();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
+
+NSRect IMEInputHandler::FirstRectForCharacterRange(NSRange& aRange,
+                                                   NSRange* aActualRange) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::FirstRectForCharacterRange, Destroyed()=%s, "
+           "aRange={ location=%lu, length=%lu }, aActualRange=%p }",
+           this, TrueOrFalse(Destroyed()),
+           static_cast<unsigned long>(aRange.location),
+           static_cast<unsigned long>(aRange.length), aActualRange));
+
+  // XXX this returns first character rect or caret rect, it is limitation of
+  // now. We need more work for returns first line rect. But current
+  // implementation is enough for IMEs.
+
+  NSRect rect = NSMakeRect(0.0, 0.0, 0.0, 0.0);
+  NSRange actualRange = NSMakeRange(NSNotFound, 0);
+  if (aActualRange) {
+    *aActualRange = actualRange;
+  }
+  if (Destroyed() || aRange.location == NSNotFound) {
+    return rect;
+  }
+
+  RefPtr<IMEInputHandler> kungFuDeathGrip(this);
+
+  LayoutDeviceIntRect r;
+  bool useCaretRect = (aRange.length == 0);
+  if (!useCaretRect) {
+    WidgetQueryContentEvent queryTextRectEvent(true, eQueryTextRect, mWidget);
+    WidgetQueryContentEvent::Options options;
+    int64_t startOffset = aRange.location;
+    if (IsIMEComposing()) {
+      // The composition may be at different offset from the selection start
+      // offset at dispatching compositionstart because start of composition
+      // is fixed when composition string becomes non-empty in the editor.
+      // Therefore, we need to use query event which is relative to insertion
+      // point.
+      options.mRelativeToInsertionPoint = true;
+      startOffset -= mIMECompositionStart;
+    }
+    queryTextRectEvent.InitForQueryTextRect(startOffset, 1, options);
+    DispatchEvent(queryTextRectEvent);
+    if (queryTextRectEvent.Succeeded()) {
+      r = queryTextRectEvent.mReply->mRect;
+      actualRange = MakeNSRangeFrom(queryTextRectEvent.mReply->mOffsetAndData);
+      mWritingMode = queryTextRectEvent.mReply->WritingModeRef();
+      mRangeForWritingMode = actualRange;
+    } else {
+      useCaretRect = true;
+    }
+  }
+
+  if (useCaretRect) {
+    WidgetQueryContentEvent queryCaretRectEvent(true, eQueryCaretRect, mWidget);
+    WidgetQueryContentEvent::Options options;
+    int64_t startOffset = aRange.location;
+    if (IsIMEComposing()) {
+      // The composition may be at different offset from the selection start
+      // offset at dispatching compositionstart because start of composition
+      // is fixed when composition string becomes non-empty in the editor.
+      // Therefore, we need to use query event which is relative to insertion
+      // point.
+      options.mRelativeToInsertionPoint = true;
+      startOffset -= mIMECompositionStart;
+    }
+    queryCaretRectEvent.InitForQueryCaretRect(startOffset, options);
+    DispatchEvent(queryCaretRectEvent);
+    if (queryCaretRectEvent.Failed()) {
+      return rect;
+    }
+    r = queryCaretRectEvent.mReply->mRect;
+    r.width = 0;
+    actualRange.location = queryCaretRectEvent.mReply->StartOffset();
+    actualRange.length = 0;
+  }
+
+  nsIWidget* rootWidget = mWidget->GetTopLevelWidget();
+  NSWindow* rootWindow =
+      static_cast<NSWindow*>(rootWidget->GetNativeData(NS_NATIVE_WINDOW));
+  NSView* rootView =
+      static_cast<NSView*>(rootWidget->GetNativeData(NS_NATIVE_WIDGET));
+  if (!rootWindow || !rootView) {
+    return rect;
+  }
+  rect = nsCocoaUtils::DevPixelsToCocoaPoints(r, mWidget->BackingScaleFactor());
+  rect = [rootView convertRect:rect toView:nil];
+  rect.origin = nsCocoaUtils::ConvertPointToScreen(rootWindow, rect.origin);
+
+  if (aActualRange) {
+    *aActualRange = actualRange;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p   IMEInputHandler::FirstRectForCharacterRange, "
+           "useCaretRect=%s rect={ x=%f, y=%f, width=%f, height=%f }, "
+           "actualRange={ location=%lu, length=%lu }",
+           this, TrueOrFalse(useCaretRect), rect.origin.x, rect.origin.y,
+           rect.size.width, rect.size.height,
+           static_cast<unsigned long>(actualRange.location),
+           static_cast<unsigned long>(actualRange.length)));
+
+  return rect;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NSMakeRect(0.0, 0.0, 0.0, 0.0));
+}
+
+NSUInteger IMEInputHandler::CharacterIndexForPoint(NSPoint& aPoint) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::CharacterIndexForPoint, aPoint={ x=%f, y=%f }",
+           this, aPoint.x, aPoint.y));
+
+  NSWindow* mainWindow = [NSApp mainWindow];
+  if (!mWidget || !mainWindow) {
+    return NSNotFound;
+  }
+
+  WidgetQueryContentEvent queryCharAtPointEvent(true, eQueryCharacterAtPoint,
+                                                mWidget);
+  NSPoint ptInWindow = nsCocoaUtils::ConvertPointFromScreen(mainWindow, aPoint);
+  NSPoint ptInView = [mView convertPoint:ptInWindow fromView:nil];
+  queryCharAtPointEvent.mRefPoint.x =
+      static_cast<int32_t>(ptInView.x * mWidget->BackingScaleFactor());
+  queryCharAtPointEvent.mRefPoint.y =
+      static_cast<int32_t>(ptInView.y * mWidget->BackingScaleFactor());
+  mWidget->DispatchWindowEvent(queryCharAtPointEvent);
+  if (queryCharAtPointEvent.Failed() ||
+      queryCharAtPointEvent.DidNotFindChar() ||
+      queryCharAtPointEvent.mReply->StartOffset() >=
+          static_cast<uint32_t>(NSNotFound)) {
+    return NSNotFound;
+  }
+
+  return queryCharAtPointEvent.mReply->StartOffset();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NSNotFound);
+}
+
+extern "C" {
+extern NSString* NSTextInputReplacementRangeAttributeName;
+}
+
+NSArray* IMEInputHandler::GetValidAttributesForMarkedText() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::GetValidAttributesForMarkedText", this));
+
+  // Return same attributes as Chromium (see render_widget_host_view_mac.mm)
+  // because most IMEs must be tested with Safari (OS default) and Chrome
+  // (having most market share).  Therefore, we need to follow their behavior.
+  // XXX It might be better to reuse an array instance for this result because
+  //     this may be called a lot.  Note that Chromium does so.
+  return
+      [NSArray arrayWithObjects:NSUnderlineStyleAttributeName,
+                                NSUnderlineColorAttributeName,
+                                NSMarkedClauseSegmentAttributeName,
+                                NSTextInputReplacementRangeAttributeName, nil];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+#pragma mark -
+
+/******************************************************************************
+ *
+ *  IMEInputHandler implementation #2
+ *
+ ******************************************************************************/
+
+IMEInputHandler::IMEInputHandler(nsChildView* aWidget,
+                                 NSView<mozView>* aNativeView)
+    : TextInputHandlerBase(aWidget, aNativeView),
+      mPendingMethods(0),
+      mIMECompositionString(nullptr),
+      mIMECompositionStart(UINT32_MAX),
+      mRangeForWritingMode(),
+      mIsIMEComposing(false),
+      mIsDeadKeyComposing(false),
+      mIsIMEEnabled(true),
+      mIsASCIICapableOnly(false),
+      mIgnoreIMECommit(false),
+      mIMEHasFocus(false) {
+  InitStaticMembers();
+
+  mMarkedRange.location = NSNotFound;
+  mMarkedRange.length = 0;
+  mSelectedRange.location = NSNotFound;
+  mSelectedRange.length = 0;
+}
+
+IMEInputHandler::~IMEInputHandler() {
+  if (mTimer) {
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
+  if (sFocusedIMEHandler == this) {
+    sFocusedIMEHandler = nullptr;
+  }
+  if (mIMECompositionString) {
+    [mIMECompositionString release];
+    mIMECompositionString = nullptr;
+  }
+}
+
+void IMEInputHandler::OnFocusChangeInGecko(bool aFocus) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("%p IMEInputHandler::OnFocusChangeInGecko, aFocus=%s, Destroyed()=%s, "
+       "sFocusedIMEHandler=%p",
+       this, TrueOrFalse(aFocus), TrueOrFalse(Destroyed()),
+       sFocusedIMEHandler));
+
+  mSelectedRange.location = NSNotFound;  // Marking dirty
+  mIMEHasFocus = aFocus;
+
+  // This is called when the native focus is changed and when the native focus
+  // isn't changed but the focus is changed in Gecko.
+  if (!aFocus) {
+    if (sFocusedIMEHandler == this) sFocusedIMEHandler = nullptr;
+    return;
+  }
+
+  sFocusedIMEHandler = this;
+
+  // We need to notify IME of focus change in Gecko as native focus change
+  // because the window level of the focused element in Gecko may be changed.
+  mPendingMethods |= kNotifyIMEOfFocusChangeInGecko;
+  ResetTimer();
+}
+
+bool IMEInputHandler::OnDestroyWidget(nsChildView* aDestroyingWidget) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::OnDestroyWidget, aDestroyingWidget=%p, "
+           "sFocusedIMEHandler=%p, IsIMEComposing()=%s",
+           this, aDestroyingWidget, sFocusedIMEHandler,
+           TrueOrFalse(IsIMEComposing())));
+
+  // If we're not focused, the focused IMEInputHandler may have been
+  // created by another widget/nsChildView.
+  if (sFocusedIMEHandler && sFocusedIMEHandler != this) {
+    sFocusedIMEHandler->OnDestroyWidget(aDestroyingWidget);
+  }
+
+  if (!TextInputHandlerBase::OnDestroyWidget(aDestroyingWidget)) {
+    return false;
+  }
+
+  if (IsIMEComposing()) {
+    // If our view is in the composition, we should clean up it.
+    CancelIMEComposition();
+  }
+
+  mSelectedRange.location = NSNotFound;  // Marking dirty
+  mIMEHasFocus = false;
+
+  return true;
+}
+
+void IMEInputHandler::SendCommittedText(NSString* aString) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::SendCommittedText, mView=%p, mWidget=%p, "
+           "inputContext=%p, mIsIMEComposing=%s",
+           this, mView, mWidget, mView ? [mView inputContext] : nullptr,
+           TrueOrFalse(mIsIMEComposing)));
+
+  NS_ENSURE_TRUE(mWidget, );
+  // XXX We should send the string without mView.
+  if (!mView) {
+    return;
+  }
+
+  if ([mView conformsToProtocol:@protocol(NSTextInputClient)]) {
+    NSObject<NSTextInputClient>* textInputClient =
+        static_cast<NSObject<NSTextInputClient>*>(mView);
+    [textInputClient insertText:aString
+               replacementRange:NSMakeRange(NSNotFound, 0)];
+  }
+
+  // Last resort.  If we cannot retrieve NSTextInputProtocol from mView
+  // or blocking to call our InsertText(), we should call InsertText()
+  // directly to commit composition forcibly.
+  if (mIsIMEComposing) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("%p   IMEInputHandler::SendCommittedText, trying to insert text "
+             "directly "
+             "due to IME not calling our InsertText()",
+             this));
+    static_cast<TextInputHandler*>(this)->InsertText(aString);
+    MOZ_ASSERT(!mIsIMEComposing);
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void IMEInputHandler::KillIMEComposition() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::KillIMEComposition, mView=%p, mWidget=%p, "
+           "inputContext=%p, mIsIMEComposing=%s, "
+           "Destroyed()=%s, IsFocused()=%s",
+           this, mView, mWidget, mView ? [mView inputContext] : nullptr,
+           TrueOrFalse(mIsIMEComposing), TrueOrFalse(Destroyed()),
+           TrueOrFalse(IsFocused())));
+
+  if (Destroyed() || NS_WARN_IF(!mView)) {
+    return;
+  }
+
+  NSTextInputContext* inputContext = [mView inputContext];
+  if (NS_WARN_IF(!inputContext)) {
+    return;
+  }
+  [inputContext discardMarkedText];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void IMEInputHandler::CommitIMEComposition() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::CommitIMEComposition, mIMECompositionString=%s",
+           this, GetCharacters(mIMECompositionString)));
+
+  // If this is called before dispatching eCompositionStart, IsIMEComposing()
+  // returns false.  Even in such case, we need to commit composition *in*
+  // IME if this is called by preceding eKeyDown event of eCompositionStart.
+  // So, we need to call KillIMEComposition() even when IsIMEComposing()
+  // returns false.
+  KillIMEComposition();
+
+  if (!IsIMEComposing()) return;
+
+  // If the composition is still there, KillIMEComposition only kills the
+  // composition in TSM.  We also need to finish the our composition too.
+  SendCommittedText(mIMECompositionString);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void IMEInputHandler::CancelIMEComposition() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!IsIMEComposing()) return;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::CancelIMEComposition, mIMECompositionString=%s",
+           this, GetCharacters(mIMECompositionString)));
+
+  // For canceling the current composing, we need to ignore the param of
+  // insertText.  But this code is ugly...
+  mIgnoreIMECommit = true;
+  KillIMEComposition();
+  mIgnoreIMECommit = false;
+
+  if (!IsIMEComposing()) return;
+
+  // If the composition is still there, KillIMEComposition only kills the
+  // composition in TSM.  We also need to kill the our composition too.
+  SendCommittedText(@"");
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+bool IMEInputHandler::IsFocused() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NS_ENSURE_TRUE(!Destroyed(), false);
+  NSWindow* window = [mView window];
+  NS_ENSURE_TRUE(window, false);
+  return [window firstResponder] == mView && [window isKeyWindow] &&
+         [[NSApplication sharedApplication] isActive];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
+
+bool IMEInputHandler::IsIMEOpened() {
+  TISInputSourceWrapper tis;
+  tis.InitByCurrentInputSource();
+  return tis.IsOpenedIMEMode();
+}
+
+void IMEInputHandler::SetASCIICapableOnly(bool aASCIICapableOnly) {
+  if (aASCIICapableOnly == mIsASCIICapableOnly) return;
+
+  CommitIMEComposition();
+  mIsASCIICapableOnly = aASCIICapableOnly;
+  SyncASCIICapableOnly();
+}
+
+void IMEInputHandler::EnableIME(bool aEnableIME) {
+  if (aEnableIME == mIsIMEEnabled) return;
+
+  CommitIMEComposition();
+  mIsIMEEnabled = aEnableIME;
+}
+
+void IMEInputHandler::SetIMEOpenState(bool aOpenIME) {
+  if (!IsFocused() || IsIMEOpened() == aOpenIME) return;
+
+  if (!aOpenIME) {
+    TISInputSourceWrapper tis;
+    tis.InitByCurrentASCIICapableInputSource();
+    tis.Select();
+    return;
+  }
+
+  // If we know the latest IME opened mode, we should select it.
+  if (sLatestIMEOpenedModeInputSourceID) {
+    TISInputSourceWrapper tis;
+    tis.InitByInputSourceID(sLatestIMEOpenedModeInputSourceID);
+    tis.Select();
+    return;
+  }
+
+  // XXX If the current input source is a mode of IME, we should turn on it,
+  // but we haven't found such way...
+
+  // Finally, we should refer the system locale but this is a little expensive,
+  // we shouldn't retry this (if it was succeeded, we already set
+  // sLatestIMEOpenedModeInputSourceID at that time).
+  static bool sIsPrefferredIMESearched = false;
+  if (sIsPrefferredIMESearched) return;
+  sIsPrefferredIMESearched = true;
+  OpenSystemPreferredLanguageIME();
+}
+
+void IMEInputHandler::OpenSystemPreferredLanguageIME() {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::OpenSystemPreferredLanguageIME", this));
+
+  CFArrayRef langList = ::CFLocaleCopyPreferredLanguages();
+  if (!langList) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("%p   IMEInputHandler::OpenSystemPreferredLanguageIME, langList "
+             "is NULL",
+             this));
+    return;
+  }
+  CFIndex count = ::CFArrayGetCount(langList);
+  for (CFIndex i = 0; i < count; i++) {
+    CFLocaleRef locale = ::CFLocaleCreate(
+        kCFAllocatorDefault,
+        static_cast<CFStringRef>(::CFArrayGetValueAtIndex(langList, i)));
+    if (!locale) {
+      continue;
+    }
+
+    bool changed = false;
+    CFStringRef lang = static_cast<CFStringRef>(
+        ::CFLocaleGetValue(locale, kCFLocaleLanguageCode));
+    NS_ASSERTION(lang, "lang is null");
+    if (lang) {
+      TISInputSourceWrapper tis;
+      tis.InitByLanguage(lang);
+      if (tis.IsOpenedIMEMode()) {
+        if (MOZ_LOG_TEST(gIMELog, LogLevel::Info)) {
+          CFStringRef foundTIS;
+          tis.GetInputSourceID(foundTIS);
+          MOZ_LOG(gIMELog, LogLevel::Info,
+                  ("%p   IMEInputHandler::OpenSystemPreferredLanguageIME, "
+                   "foundTIS=%s, lang=%s",
+                   this, GetCharacters(foundTIS), GetCharacters(lang)));
+        }
+        tis.Select();
+        changed = true;
+      }
+    }
+    ::CFRelease(locale);
+    if (changed) {
+      break;
+    }
+  }
+  ::CFRelease(langList);
+}
+
+void IMEInputHandler::OnSelectionChange(
+    const IMENotification& aIMENotification) {
+  MOZ_ASSERT(aIMENotification.mSelectionChangeData.IsInitialized());
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("%p IMEInputHandler::OnSelectionChange", this));
+
+  if (!aIMENotification.mSelectionChangeData.HasRange()) {
+    mSelectedRange.location = NSNotFound;
+    mSelectedRange.length = 0;
+    mRangeForWritingMode.location = NSNotFound;
+    mRangeForWritingMode.length = 0;
+    return;
+  }
+
+  mWritingMode = aIMENotification.mSelectionChangeData.GetWritingMode();
+  mRangeForWritingMode =
+      NSMakeRange(aIMENotification.mSelectionChangeData.mOffset,
+                  aIMENotification.mSelectionChangeData.Length());
+  if (mIMEHasFocus) {
+    mSelectedRange = mRangeForWritingMode;
+  }
+}
+
+void IMEInputHandler::OnLayoutChange() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!IsFocused()) {
+    return;
+  }
+  NSTextInputContext* inputContext = [mView inputContext];
+  [inputContext invalidateCharacterCoordinates];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+bool IMEInputHandler::OnHandleEvent(NSEvent* aEvent) {
+  if (!IsFocused()) {
+    return false;
+  }
+
+  bool allowConsumeEvent = true;
+  if (!IsIMEComposing()) {
+    // Hack for bug of Korean IMEs on Catalina (10.15).
+    // If we are inactivated during composition, active Korean IME keeps
+    // consuming all mousedown events of any mouse buttons.  So, we should
+    // allow Korean IMEs to handle mousedown events only when there is
+    // composition string.
+    // List of ID of Korean IME:
+    // * com.apple.inputmethod.Korean.2SetKorean
+    // * com.apple.inputmethod.Korean.3SetKorean
+    // * com.apple.inputmethod.Korean.390Sebulshik
+    // * com.apple.inputmethod.Korean.GongjinCheongRomaja
+    // * com.apple.inputmethod.Korean.HNCRomaja
+    TISInputSourceWrapper tis;
+    tis.InitByCurrentInputSource();
+    nsAutoString inputSourceID;
+    tis.GetInputSourceID(inputSourceID);
+    allowConsumeEvent =
+        !StringBeginsWith(inputSourceID, u"com.apple.inputmethod.Korean."_ns);
+  }
+  NSTextInputContext* inputContext = [mView inputContext];
+  return [inputContext handleEvent:aEvent] && allowConsumeEvent;
+}
+
+#pragma mark -
+
+/******************************************************************************
+ *
+ *  TextInputHandlerBase implementation
+ *
+ ******************************************************************************/
+
+int32_t TextInputHandlerBase::sSecureEventInputCount = 0;
+
+NS_IMPL_ISUPPORTS(TextInputHandlerBase, TextEventDispatcherListener,
+                  nsISupportsWeakReference)
+
+TextInputHandlerBase::TextInputHandlerBase(nsChildView* aWidget,
+                                           NSView<mozView>* aNativeView)
+    : mWidget(aWidget), mDispatcher(aWidget->GetTextEventDispatcher()) {
+  gHandlerInstanceCount++;
+  mView = [aNativeView retain];
+}
+
+TextInputHandlerBase::~TextInputHandlerBase() {
+  [mView release];
+  if (--gHandlerInstanceCount == 0) {
+    TISInputSourceWrapper::Shutdown();
+  }
+}
+
+bool TextInputHandlerBase::OnDestroyWidget(nsChildView* aDestroyingWidget) {
+  MOZ_LOG_KEY_OR_IME(LogLevel::Info,
+                     ("%p TextInputHandlerBase::OnDestroyWidget, "
+                      "aDestroyingWidget=%p, mWidget=%p",
+                      this, aDestroyingWidget, mWidget));
+
+  if (aDestroyingWidget != mWidget) {
+    return false;
+  }
+
+  mWidget = nullptr;
+  mDispatcher = nullptr;
+  return true;
+}
+
+bool TextInputHandlerBase::DispatchEvent(WidgetGUIEvent& aEvent) {
+  return mWidget->DispatchWindowEvent(aEvent);
+}
+
+void TextInputHandlerBase::InitKeyEvent(NSEvent* aNativeKeyEvent,
+                                        WidgetKeyboardEvent& aKeyEvent,
+                                        bool aIsProcessedByIME,
+                                        const nsAString* aInsertString) {
+  NS_ASSERTION(aNativeKeyEvent, "aNativeKeyEvent must not be NULL");
+
+  if (mKeyboardOverride.mOverrideEnabled) {
+    TISInputSourceWrapper tis;
+    tis.InitByLayoutID(mKeyboardOverride.mKeyboardLayout, true);
+    tis.InitKeyEvent(aNativeKeyEvent, aKeyEvent, aIsProcessedByIME,
+                     aInsertString);
+    return;
+  }
+  TISInputSourceWrapper::CurrentInputSource().InitKeyEvent(
+      aNativeKeyEvent, aKeyEvent, aIsProcessedByIME, aInsertString);
+}
+
+nsresult TextInputHandlerBase::SynthesizeNativeKeyEvent(
+    int32_t aNativeKeyboardLayout, int32_t aNativeKeyCode,
+    uint32_t aModifierFlags, const nsAString& aCharacters,
+    const nsAString& aUnmodifiedCharacters) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  uint32_t modifierFlags =
+      nsCocoaUtils::ConvertWidgetModifiersToMacModifierFlags(
+          static_cast<nsIWidget::Modifiers>(aModifierFlags));
+  NSInteger windowNumber = [[mView window] windowNumber];
+  bool sendFlagsChangedEvent = IsModifierKey(aNativeKeyCode);
+  NSEventType eventType =
+      sendFlagsChangedEvent ? NSEventTypeFlagsChanged : NSEventTypeKeyDown;
+  NSEvent* downEvent =
+      [NSEvent keyEventWithType:eventType
+                             location:NSMakePoint(0, 0)
+                        modifierFlags:modifierFlags
+                            timestamp:0
+                         windowNumber:windowNumber
+                              context:nil
+                           characters:nsCocoaUtils::ToNSString(aCharacters)
+          charactersIgnoringModifiers:nsCocoaUtils::ToNSString(
+                                          aUnmodifiedCharacters)
+                            isARepeat:NO
+                              keyCode:aNativeKeyCode];
+
+  NSEvent* upEvent = sendFlagsChangedEvent
+                         ? nil
+                         : nsCocoaUtils::MakeNewCocoaEventWithType(
+                               NSEventTypeKeyUp, downEvent);
+
+  if (downEvent && (sendFlagsChangedEvent || upEvent)) {
+    KeyboardLayoutOverride currentLayout = mKeyboardOverride;
+    mKeyboardOverride.mKeyboardLayout = aNativeKeyboardLayout;
+    mKeyboardOverride.mOverrideEnabled = true;
+    [NSApp sendEvent:downEvent];
+    if (upEvent) {
+      [NSApp sendEvent:upEvent];
+    }
+    // processKeyDownEvent and keyUp block exceptions so we're sure to
+    // reach here to restore mKeyboardOverride
+    mKeyboardOverride = currentLayout;
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NSInteger TextInputHandlerBase::GetWindowLevel() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_LOG_KEY_OR_IME(LogLevel::Info,
+                     ("%p TextInputHandlerBase::GetWindowLevel, Destryoed()=%s",
+                      this, TrueOrFalse(Destroyed())));
+
+  if (Destroyed()) {
+    return NSNormalWindowLevel;
+  }
+
+  // When an <input> element on a XUL <panel> is focused, the actual focused
+  // view is the panel's parent view (mView). But the editor is displayed on the
+  // popped-up widget's view (editorView).  We want the latter's window level.
+  NSView<mozView>* editorView = mWidget->GetEditorView();
+  NS_ENSURE_TRUE(editorView, NSNormalWindowLevel);
+  NSInteger windowLevel = [[editorView window] level];
+
+  MOZ_LOG_KEY_OR_IME(
+      LogLevel::Info,
+      ("%p TextInputHandlerBase::GetWindowLevel, windowLevel=%s (%lX)", this,
+       GetWindowLevelName(windowLevel),
+       static_cast<unsigned long>(windowLevel)));
+
+  return windowLevel;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NSNormalWindowLevel);
+}
+
+NS_IMETHODIMP
+TextInputHandlerBase::AttachNativeKeyEvent(WidgetKeyboardEvent& aKeyEvent) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // Don't try to replace a native event if one already exists.
+  // OS X doesn't have an OS modifier, can't make a native event.
+  if (aKeyEvent.mNativeKeyEvent) {
+    return NS_OK;
+  }
+
+  MOZ_LOG_KEY_OR_IME(
+      LogLevel::Info,
+      ("%p TextInputHandlerBase::AttachNativeKeyEvent, key=0x%X, char=0x%X, "
+       "mod=0x%X",
+       this, aKeyEvent.mKeyCode, aKeyEvent.mCharCode, aKeyEvent.mModifiers));
+
+  NSInteger windowNumber = [[mView window] windowNumber];
+  NSGraphicsContext* context = [NSGraphicsContext currentContext];
+  aKeyEvent.mNativeKeyEvent = nsCocoaUtils::MakeNewCococaEventFromWidgetEvent(
+      aKeyEvent, windowNumber, context);
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+bool TextInputHandlerBase::SetSelection(NSRange& aRange) {
+  MOZ_ASSERT(!Destroyed());
+
+  RefPtr<TextInputHandlerBase> kungFuDeathGrip(this);
+  WidgetSelectionEvent selectionEvent(true, eSetSelection, mWidget);
+  selectionEvent.mOffset = aRange.location;
+  selectionEvent.mLength = aRange.length;
+  selectionEvent.mReversed = false;
+  selectionEvent.mExpandToClusterBoundary = false;
+  DispatchEvent(selectionEvent);
+  NS_ENSURE_TRUE(selectionEvent.mSucceeded, false);
+  return !Destroyed();
+}
+
+/* static */ bool TextInputHandlerBase::IsPrintableChar(char16_t aChar) {
+  return (aChar >= 0x20 && aChar <= 0x7E) || aChar >= 0xA0;
+}
+
+/* static */ bool TextInputHandlerBase::IsSpecialGeckoKey(
+    UInt32 aNativeKeyCode) {
+  // this table is used to determine which keys are special and should not
+  // generate a charCode
+  switch (aNativeKeyCode) {
+    // modifiers - we don't get separate events for these yet
+    case kVK_Escape:
+    case kVK_Shift:
+    case kVK_RightShift:
+    case kVK_Command:
+    case kVK_RightCommand:
+    case kVK_CapsLock:
+    case kVK_Control:
+    case kVK_RightControl:
+    case kVK_Option:
+    case kVK_RightOption:
+    case kVK_ANSI_KeypadClear:
+    case kVK_Function:
+
+    // function keys
+    case kVK_F1:
+    case kVK_F2:
+    case kVK_F3:
+    case kVK_F4:
+    case kVK_F5:
+    case kVK_F6:
+    case kVK_F7:
+    case kVK_F8:
+    case kVK_F9:
+    case kVK_F10:
+    case kVK_F11:
+    case kVK_F12:
+    case kVK_PC_Pause:
+    case kVK_PC_ScrollLock:
+    case kVK_PC_PrintScreen:
+    case kVK_F16:
+    case kVK_F17:
+    case kVK_F18:
+    case kVK_F19:
+
+    case kVK_PC_Insert:
+    case kVK_PC_Delete:
+    case kVK_Tab:
+    case kVK_PC_Backspace:
+    case kVK_PC_ContextMenu:
+
+    case kVK_JIS_Eisu:
+    case kVK_JIS_Kana:
+
+    case kVK_Home:
+    case kVK_End:
+    case kVK_PageUp:
+    case kVK_PageDown:
+    case kVK_LeftArrow:
+    case kVK_RightArrow:
+    case kVK_UpArrow:
+    case kVK_DownArrow:
+    case kVK_Return:
+    case kVK_ANSI_KeypadEnter:
+    case kVK_Powerbook_KeypadEnter:
+      return true;
+  }
+  return false;
+}
+
+/* static */ bool TextInputHandlerBase::IsNormalCharInputtingEvent(
+    NSEvent* aNativeEvent) {
+  if ([aNativeEvent type] != NSEventTypeKeyDown &&
+      [aNativeEvent type] != NSEventTypeKeyUp) {
+    return false;
+  }
+  nsAutoString nativeChars;
+  nsCocoaUtils::GetStringForNSString([aNativeEvent characters], nativeChars);
+
+  // this is not character inputting event, simply.
+  if (nativeChars.IsEmpty() ||
+      ([aNativeEvent modifierFlags] & NSEventModifierFlagCommand)) {
+    return false;
+  }
+  return !IsControlChar(nativeChars[0]);
+}
+
+/* static */ bool TextInputHandlerBase::IsModifierKey(UInt32 aNativeKeyCode) {
+  switch (aNativeKeyCode) {
+    case kVK_CapsLock:
+    case kVK_RightCommand:
+    case kVK_Command:
+    case kVK_Shift:
+    case kVK_Option:
+    case kVK_Control:
+    case kVK_RightShift:
+    case kVK_RightOption:
+    case kVK_RightControl:
+    case kVK_Function:
+      return true;
+  }
+  return false;
+}
+
+/* static */ void TextInputHandlerBase::EnableSecureEventInput() {
+  sSecureEventInputCount++;
+  ::EnableSecureEventInput();
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("EnableSecureEventInput() called (%d)", sSecureEventInputCount));
+}
+
+/* static */ void TextInputHandlerBase::DisableSecureEventInput() {
+  if (!sSecureEventInputCount) {
+    return;
+  }
+  sSecureEventInputCount--;
+  ::DisableSecureEventInput();
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("DisableSecureEventInput() called (%d)", sSecureEventInputCount));
+}
+
+/* static */ bool TextInputHandlerBase::IsSecureEventInputEnabled() {
+  // sSecureEventInputCount is our mechanism to track when Secure Event Input
+  //   is enabled. Non-zero indicates we have enabled Secure Input. But
+  //   zero does not mean that Secure Input is _disabled_ because another
+  //   application may have enabled it.  If the OS reports Secure Event
+  //   Input is disabled though, a non-zero sSecureEventInputCount is an error.
+  NS_ASSERTION(::IsSecureEventInputEnabled() || 0 == sSecureEventInputCount,
+               "sSecureEventInputCount is not zero when the OS thinks "
+               "SecureEventInput is disabled.");
+  return !!sSecureEventInputCount;
+}
+
+/* static */ void TextInputHandlerBase::EnsureSecureEventInputDisabled() {
+  while (sSecureEventInputCount) {
+    TextInputHandlerBase::DisableSecureEventInput();
+  }
+}
+
+#pragma mark -
+
+/******************************************************************************
+ *
+ *  TextInputHandlerBase::KeyEventState implementation
+ *
+ ******************************************************************************/
+
+void TextInputHandlerBase::KeyEventState::InitKeyEvent(
+    TextInputHandlerBase* aHandler, WidgetKeyboardEvent& aKeyEvent,
+    bool aIsProcessedByIME) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_ASSERT(aHandler);
+  MOZ_RELEASE_ASSERT(mKeyEvent);
+
+  NSEvent* nativeEvent = mKeyEvent;
+  if (!mInsertedString.IsEmpty()) {
+    nsAutoString unhandledString;
+    GetUnhandledString(unhandledString);
+    NSString* unhandledNSString = nsCocoaUtils::ToNSString(unhandledString);
+    // If the key event's some characters were already handled by
+    // InsertString() calls, we need to create a dummy event which doesn't
+    // include the handled characters.
+    nativeEvent =
+        [NSEvent keyEventWithType:[mKeyEvent type]
+                               location:[mKeyEvent locationInWindow]
+                          modifierFlags:[mKeyEvent modifierFlags]
+                              timestamp:[mKeyEvent timestamp]
+                           windowNumber:[mKeyEvent windowNumber]
+                                context:nil
+                             characters:unhandledNSString
+            charactersIgnoringModifiers:[mKeyEvent charactersIgnoringModifiers]
+                              isARepeat:[mKeyEvent isARepeat]
+                                keyCode:[mKeyEvent keyCode]];
+  }
+
+  aKeyEvent.mUniqueId = mUniqueId;
+  aHandler->InitKeyEvent(nativeEvent, aKeyEvent, aIsProcessedByIME,
+                         mInsertString);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void TextInputHandlerBase::KeyEventState::GetUnhandledString(
+    nsAString& aUnhandledString) const {
+  aUnhandledString.Truncate();
+  if (NS_WARN_IF(!mKeyEvent)) {
+    return;
+  }
+  nsAutoString characters;
+  nsCocoaUtils::GetStringForNSString([mKeyEvent characters], characters);
+  if (characters.IsEmpty()) {
+    return;
+  }
+  if (mInsertedString.IsEmpty()) {
+    aUnhandledString = characters;
+    return;
+  }
+
+  // The insertes string must match with the start of characters.
+  MOZ_ASSERT(StringBeginsWith(characters, mInsertedString));
+
+  aUnhandledString = nsDependentSubstring(characters, mInsertedString.Length());
+}
+
+#pragma mark -
+
+/******************************************************************************
+ *
+ *  TextInputHandlerBase::AutoInsertStringClearer implementation
+ *
+ ******************************************************************************/
+
+TextInputHandlerBase::AutoInsertStringClearer::~AutoInsertStringClearer() {
+  if (mState && mState->mInsertString) {
+    // If inserting string is a part of characters of the event,
+    // we should record it as inserted string.
+    nsAutoString characters;
+    nsCocoaUtils::GetStringForNSString([mState->mKeyEvent characters],
+                                       characters);
+    nsAutoString insertedString(mState->mInsertedString);
+    insertedString += *mState->mInsertString;
+    if (StringBeginsWith(characters, insertedString)) {
+      mState->mInsertedString = insertedString;
+    }
+  }
+  if (mState) {
+    mState->mInsertString = nullptr;
+  }
+}
+
+#undef MOZ_LOG_KEY_OR_IME
diff --git a/widget/cocoa/TextRecognition.mm b/widget/cocoa/TextRecognition.mm
new file mode 100644
index 0000000000..c365f51982
--- /dev/null
+++ b/widget/cocoa/TextRecognition.mm
@@ -0,0 +1,121 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Vision/Vision.h>
+
+#include "mozilla/dom/Promise.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/ErrorResult.h"
+#include "ErrorList.h"
+#include "nsClipboard.h"
+#include "nsCocoaUtils.h"
+#include "mozilla/MacStringHelpers.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/widget/TextRecognition.h"
+#include "mozilla/dom/PContent.h"
+
+namespace mozilla::widget {
+
+auto TextRecognition::DoFindText(gfx::DataSourceSurface& aSurface,
+                                 const nsTArray<nsCString>& aLanguages)
+    -> RefPtr<NativePromise> {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK
+
+  // TODO - Is this the most efficient path? Maybe we can write a new
+  // CreateCGImageFromXXX that enables more efficient marshalling of the data.
+  CGImageRef imageRef = NULL;
+  nsresult rv = nsCocoaUtils::CreateCGImageFromSurface(&aSurface, &imageRef);
+  if (NS_FAILED(rv) || !imageRef) {
+    return NativePromise::CreateAndReject("Failed to create CGImage"_ns,
+                                          __func__);
+  }
+
+  auto promise = MakeRefPtr<NativePromise::Private>(__func__);
+
+  NSMutableArray* recognitionLanguages = [[NSMutableArray alloc] init];
+  for (const auto& locale : aLanguages) {
+    [recognitionLanguages addObject:nsCocoaUtils::ToNSString(locale)];
+  }
+
+  NS_DispatchBackgroundTask(
+      NS_NewRunnableFunction(
+          __func__,
+          [promise, imageRef, recognitionLanguages] {
+            auto unrefImage = MakeScopeExit([&] {
+              ::CGImageRelease(imageRef);
+              [recognitionLanguages release];
+            });
+
+            dom::TextRecognitionResult result;
+            dom::TextRecognitionResult* pResult = &result;
+
+            // Define the request to use, which also handles the result. It will
+            // be run below directly in this thread. After creating this
+            // request.
+            VNRecognizeTextRequest* textRecognitionRequest =
+                [[VNRecognizeTextRequest alloc] initWithCompletionHandler:^(
+                                                    VNRequest* _Nonnull request,
+                                                    NSError* _Nullable error) {
+                  NSArray<VNRecognizedTextObservation*>* observations =
+                      request.results;
+
+                  [observations enumerateObjectsUsingBlock:^(
+                                    VNRecognizedTextObservation* _Nonnull obj,
+                                    NSUInteger idx, BOOL* _Nonnull stop) {
+                    // Requests the n top candidates for a recognized text
+                    // string.
+                    VNRecognizedText* recognizedText =
+                        [obj topCandidates:1].firstObject;
+
+                    // https://developer.apple.com/documentation/vision/vnrecognizedtext?language=objc
+                    auto& quad = *pResult->quads().AppendElement();
+                    CopyCocoaStringToXPCOMString(recognizedText.string,
+                                                 quad.string());
+                    quad.confidence() = recognizedText.confidence;
+
+                    auto ToImagePoint = [](CGPoint aPoint) -> ImagePoint {
+                      return {static_cast<float>(aPoint.x),
+                              static_cast<float>(aPoint.y)};
+                    };
+                    *quad.points().AppendElement() =
+                        ToImagePoint(obj.bottomLeft);
+                    *quad.points().AppendElement() = ToImagePoint(obj.topLeft);
+                    *quad.points().AppendElement() = ToImagePoint(obj.topRight);
+                    *quad.points().AppendElement() =
+                        ToImagePoint(obj.bottomRight);
+                  }];
+                }];
+
+            textRecognitionRequest.recognitionLevel =
+                VNRequestTextRecognitionLevelAccurate;
+            textRecognitionRequest.recognitionLanguages = recognitionLanguages;
+            textRecognitionRequest.usesLanguageCorrection = true;
+
+            // Send out the request. This blocks execution of this thread with
+            // an expensive CPU call.
+            NSError* error = nil;
+            VNImageRequestHandler* requestHandler =
+                [[[VNImageRequestHandler alloc] initWithCGImage:imageRef
+                                                        options:@{}]
+                    autorelease];
+
+            [requestHandler performRequests:@[ textRecognitionRequest ]
+                                      error:&error];
+            if (error != nil) {
+              promise->Reject(
+                  nsPrintfCString(
+                      "Failed to perform text recognition request (%ld)\n",
+                      error.code),
+                  __func__);
+            } else {
+              promise->Resolve(std::move(result), __func__);
+            }
+          }),
+      NS_DISPATCH_EVENT_MAY_BLOCK);
+  return promise;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/cocoa/VibrancyManager.h b/widget/cocoa/VibrancyManager.h
new file mode 100644
index 0000000000..d431540830
--- /dev/null
+++ b/widget/cocoa/VibrancyManager.h
@@ -0,0 +1,92 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef VibrancyManager_h
+#define VibrancyManager_h
+
+#include "mozilla/Assertions.h"
+#include "nsClassHashtable.h"
+#include "nsRegion.h"
+#include "nsTArray.h"
+#include "ViewRegion.h"
+
+#import <Foundation/NSGeometry.h>
+
+@class NSColor;
+@class NSView;
+class nsChildView;
+
+namespace mozilla {
+
+enum class VibrancyType {
+  TOOLTIP,
+  MENU,
+};
+
+/**
+ * VibrancyManager takes care of updating the vibrant regions of a window.
+ * Vibrancy is a visual look that was introduced on OS X starting with 10.10.
+ * An app declares vibrant window regions to the window server, and the window
+ * server will display a blurred rendering of the screen contents from behind
+ * the window in these areas, behind the actual window contents. Consequently,
+ * the effect is only visible in areas where the window contents are not
+ * completely opaque. Usually this is achieved by clearing the background of
+ * the window prior to drawing in the vibrant areas. This is possible even if
+ * the window is declared as opaque.
+ */
+class VibrancyManager {
+ public:
+  /**
+   * Create a new VibrancyManager instance and provide it with an NSView
+   * to attach NSVisualEffectViews to.
+   *
+   * @param aCoordinateConverter  The nsChildView to use for converting
+   *   nsIntRect device pixel coordinates into Cocoa NSRect coordinates. Must
+   *   outlive this VibrancyManager instance.
+   * @param aContainerView  The view that's going to be the superview of the
+   *   NSVisualEffectViews which will be created for vibrant regions.
+   */
+  VibrancyManager(const nsChildView& aCoordinateConverter,
+                  NSView* aContainerView)
+      : mCoordinateConverter(aCoordinateConverter),
+        mContainerView(aContainerView) {}
+
+  /**
+   * Update the placement of the NSVisualEffectViews inside the container
+   * NSView so that they cover aRegion, and create new NSVisualEffectViews
+   * or remove existing ones as needed.
+   * @param aType   The vibrancy type to use in the region.
+   * @param aRegion The vibrant area, in device pixels.
+   * @return Whether the region changed.
+   */
+  bool UpdateVibrantRegion(VibrancyType aType,
+                           const LayoutDeviceIntRegion& aRegion);
+
+  bool HasVibrantRegions() { return !mVibrantRegions.IsEmpty(); }
+
+  LayoutDeviceIntRegion GetUnionOfVibrantRegions() const;
+
+  /**
+   * Create an NSVisualEffectView for the specified vibrancy type. The return
+   * value is not autoreleased. We return an object of type NSView* because we
+   * compile with an SDK that does not contain a definition for
+   * NSVisualEffectView.
+   * @param aIsContainer Whether this NSView will have child views. This value
+   *                     affects hit testing: Container views will pass through
+   *                     hit testing requests to their children, and leaf views
+   *                     will be transparent to hit testing.
+   */
+  static NSView* CreateEffectView(VibrancyType aType, BOOL aIsContainer = NO);
+
+ protected:
+  const nsChildView& mCoordinateConverter;
+  NSView* mContainerView;
+  nsClassHashtable<nsUint32HashKey, ViewRegion> mVibrantRegions;
+};
+
+}  // namespace mozilla
+
+#endif  // VibrancyManager_h
diff --git a/widget/cocoa/VibrancyManager.mm b/widget/cocoa/VibrancyManager.mm
new file mode 100644
index 0000000000..e9cfcc3be0
--- /dev/null
+++ b/widget/cocoa/VibrancyManager.mm
@@ -0,0 +1,110 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "VibrancyManager.h"
+
+#import <objc/message.h>
+
+#include "nsChildView.h"
+
+using namespace mozilla;
+
+@interface MOZVibrantView : NSVisualEffectView {
+  VibrancyType mType;
+}
+- (instancetype)initWithFrame:(NSRect)aRect
+                 vibrancyType:(VibrancyType)aVibrancyType;
+@end
+
+@interface MOZVibrantLeafView : MOZVibrantView
+@end
+
+static NSVisualEffectState VisualEffectStateForVibrancyType(
+    VibrancyType aType) {
+  switch (aType) {
+    case VibrancyType::TOOLTIP:
+    case VibrancyType::MENU:
+      // Tooltip and menu windows are never "key", so we need to tell the
+      // vibrancy effect to look active regardless of window state.
+      return NSVisualEffectStateActive;
+    default:
+      return NSVisualEffectStateFollowsWindowActiveState;
+  }
+}
+
+static NSVisualEffectMaterial VisualEffectMaterialForVibrancyType(
+    VibrancyType aType, BOOL* aOutIsEmphasized) {
+  switch (aType) {
+    case VibrancyType::TOOLTIP:
+      return (NSVisualEffectMaterial)NSVisualEffectMaterialToolTip;
+    case VibrancyType::MENU:
+      return NSVisualEffectMaterialMenu;
+  }
+}
+
+@implementation MOZVibrantView
+
+- (instancetype)initWithFrame:(NSRect)aRect vibrancyType:(VibrancyType)aType {
+  self = [super initWithFrame:aRect];
+  mType = aType;
+
+  self.appearance = nil;
+  self.state = VisualEffectStateForVibrancyType(mType);
+
+  BOOL isEmphasized = NO;
+  self.material = VisualEffectMaterialForVibrancyType(mType, &isEmphasized);
+  self.emphasized = isEmphasized;
+
+  return self;
+}
+
+// Don't override allowsVibrancy here, because this view may have subviews, and
+// returning YES from allowsVibrancy forces on foreground vibrancy for all
+// descendant views, which can have unintended effects.
+
+@end
+
+@implementation MOZVibrantLeafView
+
+- (NSView*)hitTest:(NSPoint)aPoint {
+  // This view must be transparent to mouse events.
+  return nil;
+}
+
+// MOZVibrantLeafView does not have subviews, so we can return YES here without
+// having unintended effects on other contents of the window.
+- (BOOL)allowsVibrancy {
+  return NO;
+}
+
+@end
+
+bool VibrancyManager::UpdateVibrantRegion(
+    VibrancyType aType, const LayoutDeviceIntRegion& aRegion) {
+  if (aRegion.IsEmpty()) {
+    return mVibrantRegions.Remove(uint32_t(aType));
+  }
+  auto& vr = *mVibrantRegions.GetOrInsertNew(uint32_t(aType));
+  return vr.UpdateRegion(aRegion, mCoordinateConverter, mContainerView, ^() {
+    return this->CreateEffectView(aType);
+  });
+}
+
+LayoutDeviceIntRegion VibrancyManager::GetUnionOfVibrantRegions() const {
+  LayoutDeviceIntRegion result;
+  for (const auto& region : mVibrantRegions.Values()) {
+    result.OrWith(region->Region());
+  }
+  return result;
+}
+
+/* static */ NSView* VibrancyManager::CreateEffectView(VibrancyType aType,
+                                                       BOOL aIsContainer) {
+  return aIsContainer ? [[MOZVibrantView alloc] initWithFrame:NSZeroRect
+                                                 vibrancyType:aType]
+                      : [[MOZVibrantLeafView alloc] initWithFrame:NSZeroRect
+                                                     vibrancyType:aType];
+}
diff --git a/widget/cocoa/ViewRegion.h b/widget/cocoa/ViewRegion.h
new file mode 100644
index 0000000000..b2ed0c8835
--- /dev/null
+++ b/widget/cocoa/ViewRegion.h
@@ -0,0 +1,55 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ViewRegion_h
+#define ViewRegion_h
+
+#include "Units.h"
+#include "nsTArray.h"
+
+class nsChildView;
+
+@class NSView;
+
+namespace mozilla {
+
+/**
+ * Manages a set of NSViews to cover a LayoutDeviceIntRegion.
+ */
+class ViewRegion {
+ public:
+  ~ViewRegion();
+
+  mozilla::LayoutDeviceIntRegion Region() { return mRegion; }
+
+  /**
+   * Update the region.
+   * @param aRegion  The new region.
+   * @param aCoordinateConverter  The nsChildView to use for converting
+   *   LayoutDeviceIntRect device pixel coordinates into Cocoa NSRect
+   * coordinates.
+   * @param aContainerView  The view that's going to be the superview of the
+   *   NSViews which will be created for this region.
+   * @param aViewCreationCallback  A block that instantiates new NSViews.
+   * @return  Whether or not the region changed.
+   */
+  bool UpdateRegion(const mozilla::LayoutDeviceIntRegion& aRegion,
+                    const nsChildView& aCoordinateConverter,
+                    NSView* aContainerView, NSView* (^aViewCreationCallback)());
+
+  /**
+   * Return an NSView from the region, if there is any.
+   */
+  NSView* GetAnyView() { return mViews.Length() > 0 ? mViews[0] : NULL; }
+
+ private:
+  mozilla::LayoutDeviceIntRegion mRegion;
+  nsTArray<NSView*> mViews;
+};
+
+}  // namespace mozilla
+
+#endif  // ViewRegion_h
diff --git a/widget/cocoa/ViewRegion.mm b/widget/cocoa/ViewRegion.mm
new file mode 100644
index 0000000000..62e76d2df8
--- /dev/null
+++ b/widget/cocoa/ViewRegion.mm
@@ -0,0 +1,68 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ViewRegion.h"
+#import <Cocoa/Cocoa.h>
+
+#include "nsChildView.h"
+
+using namespace mozilla;
+
+ViewRegion::~ViewRegion() {
+  for (size_t i = 0; i < mViews.Length(); i++) {
+    [mViews[i] removeFromSuperview];
+  }
+}
+
+bool ViewRegion::UpdateRegion(const LayoutDeviceIntRegion& aRegion,
+                              const nsChildView& aCoordinateConverter,
+                              NSView* aContainerView,
+                              NSView* (^aViewCreationCallback)()) {
+  if (mRegion == aRegion) {
+    return false;
+  }
+
+  // We need to construct the required region using as many EffectViews
+  // as necessary. We try to update the geometry of existing views if
+  // possible, or create new ones or remove old ones if the number of
+  // rects in the region has changed.
+
+  nsTArray<NSView*> viewsToRecycle = std::move(mViews);
+  // The mViews array is now empty.
+
+  size_t i = 0;
+  for (auto iter = aRegion.RectIter();
+       !iter.Done() || i < viewsToRecycle.Length(); i++) {
+    if (!iter.Done()) {
+      NSView* view = nil;
+      NSRect rect = aCoordinateConverter.DevPixelsToCocoaPoints(iter.Get());
+      if (i < viewsToRecycle.Length()) {
+        view = viewsToRecycle[i];
+      } else {
+        view = aViewCreationCallback();
+        [aContainerView addSubview:view];
+
+        // Now that the view is in the view hierarchy, it'll be kept alive by
+        // its superview, so we can drop our reference.
+        [view release];
+      }
+      if (!NSEqualRects(rect, [view frame])) {
+        [view setFrame:rect];
+      }
+      [view setNeedsDisplay:YES];
+      mViews.AppendElement(view);
+      iter.Next();
+    } else {
+      // Our new region is made of fewer rects than the old region, so we can
+      // remove this view. We only have a weak reference to it, so removing it
+      // from the view hierarchy will release it.
+      [viewsToRecycle[i] removeFromSuperview];
+    }
+  }
+
+  mRegion = aRegion;
+  return true;
+}
diff --git a/widget/cocoa/WidgetTraceEvent.mm b/widget/cocoa/WidgetTraceEvent.mm
new file mode 100644
index 0000000000..54fe497e3b
--- /dev/null
+++ b/widget/cocoa/WidgetTraceEvent.mm
@@ -0,0 +1,79 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <Cocoa/Cocoa.h>
+#include "CustomCocoaEvents.h"
+#include <Foundation/NSAutoreleasePool.h>
+#include <mozilla/CondVar.h>
+#include <mozilla/Mutex.h>
+#include "mozilla/WidgetTraceEvent.h"
+
+using mozilla::CondVar;
+using mozilla::Mutex;
+using mozilla::MutexAutoLock;
+
+namespace {
+
+Mutex* sMutex = NULL;
+CondVar* sCondVar = NULL;
+bool sTracerProcessed = false;
+
+}  // namespace
+
+namespace mozilla {
+
+bool InitWidgetTracing() {
+  sMutex = new Mutex("Event tracer thread mutex");
+  sCondVar = new CondVar(*sMutex, "Event tracer thread condvar");
+  return sMutex && sCondVar;
+}
+
+void CleanUpWidgetTracing() {
+  delete sMutex;
+  delete sCondVar;
+  sMutex = NULL;
+  sCondVar = NULL;
+}
+
+// This function is called from the main (UI) thread.
+void SignalTracerThread() {
+  if (!sMutex || !sCondVar) return;
+  MutexAutoLock lock(*sMutex);
+  if (!sTracerProcessed) {
+    sTracerProcessed = true;
+    sCondVar->Notify();
+  }
+}
+
+// This function is called from the background tracer thread.
+bool FireAndWaitForTracerEvent() {
+  MOZ_ASSERT(sMutex && sCondVar, "Tracing not initialized!");
+  NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
+  MutexAutoLock lock(*sMutex);
+  if (sTracerProcessed) {
+    // Things are out of sync. This is likely because we're in
+    // the middle of shutting down. Just return false and hope the
+    // tracer thread is quitting anyway.
+    return false;
+  }
+
+  // Post an application-defined event to the main thread's event queue
+  // and wait for it to get processed.
+  [NSApp postEvent:[NSEvent otherEventWithType:NSEventTypeApplicationDefined
+                                      location:NSMakePoint(0, 0)
+                                 modifierFlags:0
+                                     timestamp:0
+                                  windowNumber:0
+                                       context:NULL
+                                       subtype:kEventSubtypeTrace
+                                         data1:0
+                                         data2:0]
+           atStart:NO];
+  while (!sTracerProcessed) sCondVar->Wait();
+  sTracerProcessed = false;
+  [pool release];
+  return true;
+}
+
+}  // namespace mozilla
diff --git a/widget/cocoa/components.conf b/widget/cocoa/components.conf
new file mode 100644
index 0000000000..e8570fd502
--- /dev/null
+++ b/widget/cocoa/components.conf
@@ -0,0 +1,168 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Headers = '/widget/cocoa/nsWidgetFactory.h',
+
+InitFunc = 'nsWidgetCocoaModuleCtor'
+UnloadFunc = 'nsWidgetCocoaModuleDtor'
+
+Classes = [
+    {
+        'cid': '{49f428e8-baf9-4ba3-b1b0-7d2fd3abbcea}',
+        'contract_ids': ['@mozilla.org/widget/parent/clipboard;1'],
+        'interfaces': ['nsIClipboard'],
+        'type': 'nsIClipboard',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'name': 'GfxInfo',
+        'cid': '{d755a760-9f27-11df-0800-200c9a664242}',
+        'contract_ids': ['@mozilla.org/gfx/info;1'],
+        'type': 'mozilla::widget::GfxInfo',
+        'headers': ['/widget/cocoa/GfxInfo.h'],
+        'init_method': 'Init',
+    },
+    {
+        'cid': '{e5170091-c16b-492d-bf00-f45d72470553}',
+        'contract_ids': ['@mozilla.org/parent/filepicker;1'],
+        'type': 'nsFilePicker',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{b90f5fdd-c23e-4ad6-a10e-1da8ffe07799}',
+        'contract_ids': ['@mozilla.org/parent/colorpicker;1'],
+        'type': 'nsColorPicker',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{2d96b3df-c051-11d1-a827-0040959a28c9}',
+        'contract_ids': ['@mozilla.org/widget/appshell/mac;1'],
+        'legacy_constructor': 'nsAppShellConstructor',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_UTILITY_AND_GMPLUGIN_PROCESS,
+    },
+    {
+        'cid': '{b148eed2-236d-11d3-b35c-00a0cc3c1cde}',
+        'contract_ids': ['@mozilla.org/sound;1'],
+        'type': 'nsSound',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{8b5314bc-db01-11d2-96ce-0060b0fb9956}',
+        'contract_ids': ['@mozilla.org/widget/transferable;1'],
+        'type': 'nsTransferable',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{948a0023-e3a7-11d2-96cf-0060b0fb9956}',
+        'contract_ids': ['@mozilla.org/widget/htmlformatconverter;1'],
+        'type': 'nsHTMLFormatConverter',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{77221d5a-1dd2-11b2-8c69-c710f15d2ed5}',
+        'contract_ids': ['@mozilla.org/widget/clipboardhelper;1'],
+        'type': 'nsClipboardHelper',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{9a155bb2-2b67-45de-83e3-13a9dacf8336}',
+        'contract_ids': ['@mozilla.org/widget/parent/dragservice;1'],
+        'type': 'nsDragService',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{f0ddedd7-e8d5-4f95-a5b4-0f48f1741b36}',
+        'contract_ids': ['@mozilla.org/gfx/parent/screenmanager;1'],
+        'type': 'mozilla::widget::ScreenManager',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        'singleton': True,
+    },
+    {
+        'cid': '{d3f69889-e13a-4321-980c-a39332e21f34}',
+        'contract_ids': ['@mozilla.org/gfx/devicecontextspec;1'],
+        'type': 'nsDeviceContextSpecX',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{a6cf9129-15b3-11d2-932e-00805f8add32}',
+        'contract_ids': ['@mozilla.org/gfx/printerlist;1'],
+        'type': 'nsPrinterListCUPS',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{841387c8-72e6-484b-9296-bf6eea80d58a}',
+        'contract_ids': ['@mozilla.org/gfx/printsettings-service;1'],
+        'type': 'nsPrintSettingsServiceX',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{06beec76-a183-4d9f-85dd-085f26da565a}',
+        'contract_ids': ['@mozilla.org/widget/printdialog-service;1'],
+        'type': 'nsPrintDialogServiceX',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{6987230e-0089-4e78-bc5f-1493ee7519fa}',
+        'contract_ids': ['@mozilla.org/widget/useridleservice;1'],
+        'type': 'nsUserIdleServiceX',
+        'singleton': True,
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{84e11f80-ca55-11dd-ad8b-0800200c9a66}',
+        'contract_ids': ['@mozilla.org/system-alerts-service;1'],
+        'type': 'mozilla::OSXNotificationCenter',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{2451baed-8dc3-46d9-9e30-96e1baa03666}',
+        'contract_ids': ['@mozilla.org/widget/macdocksupport;1'],
+        'type': 'nsMacDockSupport',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{74ea4101-a5bb-49bc-9984-66da8b225a37}',
+        'contract_ids': ['@mozilla.org/widget/macfinderprogress;1'],
+        'type': 'nsMacFinderProgress',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{de59fe1a-46c8-490f-b04d-34545acb06c9}',
+        'contract_ids': ['@mozilla.org/widget/macsharingservice;1'],
+        'type': 'nsMacSharingService',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{29046c8f-cba6-4ffa-9141-1685e96c4ea0}',
+        'contract_ids': ['@mozilla.org/widget/macuseractivityupdater;1'],
+        'type': 'nsMacUserActivityUpdater',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{e9096367-ddd9-45e4-b762-49c0c18b7119}',
+        'contract_ids': ['@mozilla.org/widget/mac-web-app-utils;1'],
+        'type': 'nsMacWebAppUtils',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{1f39ae50-b6a0-4b37-90f4-60af614193d8}',
+        'contract_ids': ['@mozilla.org/widget/standalonenativemenu;1'],
+        'type': 'nsStandaloneNativeMenu',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{b6e1a890-b2b8-4883-a65f-9476f6185313}',
+        'contract_ids': ['@mozilla.org/widget/systemstatusbar;1'],
+        'type': 'nsSystemStatusBarCocoa',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{38f396e2-93c9-4a77-aaf7-2d50b9962186}',
+        'contract_ids': ['@mozilla.org/widget/touchbarupdater;1'],
+        'type': 'nsTouchBarUpdater',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_AND_UTILITY_PROCESS,
+    },
+]
diff --git a/widget/cocoa/crashtests/373122-1-inner.html b/widget/cocoa/crashtests/373122-1-inner.html
new file mode 100644
index 0000000000..5c14166b75
--- /dev/null
+++ b/widget/cocoa/crashtests/373122-1-inner.html
@@ -0,0 +1,39 @@
+<html>
+<head>
+
+<script>
+function boom()
+{
+  document.body.style.position = "fixed"
+  
+  setTimeout(boom2, 1);
+}
+
+function boom2()
+{
+  lappy = document.getElementById("lappy");
+  lappy.style.display = "none"
+
+  setTimeout(boom3, 200);
+}
+
+function boom3()
+{
+  dump("Reloading\n");
+  location.reload();
+}
+
+</script>
+
+
+</head>
+
+
+<body bgcolor="black" onload="boom()">
+
+  <span style="overflow: scroll; display: -moz-box;"></span>
+
+  <embed id="lappy" src="" width=550 height=400 TYPE="application/x-shockwave-flash" ></embed>
+ 
+</body>
+</html>
diff --git a/widget/cocoa/crashtests/373122-1.html b/widget/cocoa/crashtests/373122-1.html
new file mode 100644
index 0000000000..a57e5f4249
--- /dev/null
+++ b/widget/cocoa/crashtests/373122-1.html
@@ -0,0 +1,9 @@
+<html class="reftest-wait">
+<head>
+<script>
+setTimeout('document.documentElement.className = ""', 1000);
+</script>
+<body>
+<iframe src="373122-1-inner.html"></iframe>
+</body>
+</html>
diff --git a/widget/cocoa/crashtests/397209-1.html b/widget/cocoa/crashtests/397209-1.html
new file mode 100644
index 0000000000..554b2dac72
--- /dev/null
+++ b/widget/cocoa/crashtests/397209-1.html
@@ -0,0 +1,7 @@
+<html>
+<head>
+</head>
+<body>
+<button style="width: 8205em;"></button>
+</body>
+</html>
diff --git a/widget/cocoa/crashtests/403296-1.xhtml b/widget/cocoa/crashtests/403296-1.xhtml
new file mode 100644
index 0000000000..800eaa3558
--- /dev/null
+++ b/widget/cocoa/crashtests/403296-1.xhtml
@@ -0,0 +1,10 @@
+<html xmlns="http://www.w3.org/1999/xhtml" 
+      class="reftest-wait"  
+      style="margin: 12em; padding: 20px 10em; opacity: 0.2; font-size: 11.2px; -moz-appearance: toolbar; white-space: nowrap;"><body 
+      style="position: absolute;" 
+      onload="setTimeout(function() { document.body.removeChild(document.getElementById('tr')); document.documentElement.removeAttribute('class'); }, 30);">
+
+xxx
+yyy
+
+<tr id="tr">300</tr></body></html>
diff --git a/widget/cocoa/crashtests/419737-1.html b/widget/cocoa/crashtests/419737-1.html
new file mode 100644
index 0000000000..fe6e4532b4
--- /dev/null
+++ b/widget/cocoa/crashtests/419737-1.html
@@ -0,0 +1,8 @@
+<!DOCTYPE html>
+<html>
+<head>
+</head>
+<body>
+<div><span style="-moz-appearance: radio; padding: 15000px;"></span></div>
+</body>
+</html>
diff --git a/widget/cocoa/crashtests/435223-1.html b/widget/cocoa/crashtests/435223-1.html
new file mode 100644
index 0000000000..c7f70860fc
--- /dev/null
+++ b/widget/cocoa/crashtests/435223-1.html
@@ -0,0 +1,8 @@
+<!DOCTYPE html>
+<html>
+<head>
+</head>
+<body>
+<div style="min-width: max-content;"><div style="-moz-appearance: button;"><div style="margin: 0 100%;"></div></div></div>
+</body>
+</html>
diff --git a/widget/cocoa/crashtests/444260-1.xhtml b/widget/cocoa/crashtests/444260-1.xhtml
new file mode 100644
index 0000000000..f1a84023df
--- /dev/null
+++ b/widget/cocoa/crashtests/444260-1.xhtml
@@ -0,0 +1,3 @@
+<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+<hbox><button width="7788025414616">S</button></hbox>
+</window>
diff --git a/widget/cocoa/crashtests/444864-1.html b/widget/cocoa/crashtests/444864-1.html
new file mode 100644
index 0000000000..f8bac76e6a
--- /dev/null
+++ b/widget/cocoa/crashtests/444864-1.html
@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+<html>
+<body>
+<div style="padding: 10px;"><input type="button" value="Go" style="letter-spacing: 331989pt;"></div>
+</body>
+</html>
diff --git a/widget/cocoa/crashtests/449111-1.html b/widget/cocoa/crashtests/449111-1.html
new file mode 100644
index 0000000000..4494591803
--- /dev/null
+++ b/widget/cocoa/crashtests/449111-1.html
@@ -0,0 +1,4 @@
+<html>
+<head></head>
+<body><div style="display: -moz-box; word-spacing: 549755813889px;"><button>T </button></div></body>
+</html>
diff --git a/widget/cocoa/crashtests/460349-1.xhtml b/widget/cocoa/crashtests/460349-1.xhtml
new file mode 100644
index 0000000000..cc9b9700c7
--- /dev/null
+++ b/widget/cocoa/crashtests/460349-1.xhtml
@@ -0,0 +1,4 @@
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head></head>
+<body><div><mstyle xmlns="http://www.w3.org/1998/Math/MathML" style="-moz-appearance: button;"/></div></body>
+</html>
diff --git a/widget/cocoa/crashtests/460387-1.html b/widget/cocoa/crashtests/460387-1.html
new file mode 100644
index 0000000000..cab7e7eb32
--- /dev/null
+++ b/widget/cocoa/crashtests/460387-1.html
@@ -0,0 +1,2 @@
+<!DOCTYPE html>
+<html><head></head><body><div style="display: table; padding: 625203mm; -moz-appearance: menulist;"></div></body></html>
diff --git a/widget/cocoa/crashtests/464589-1.html b/widget/cocoa/crashtests/464589-1.html
new file mode 100644
index 0000000000..d25d92315d
--- /dev/null
+++ b/widget/cocoa/crashtests/464589-1.html
@@ -0,0 +1,20 @@
+<html>
+<head>
+<script type="text/javascript">
+
+function boom()
+{
+  var o2 = document.createElement("option");
+  document.getElementById("o1").appendChild(o2);
+  o2.style.padding = "131072cm";
+}
+
+</script>
+</head>
+
+<body onload="boom();">
+
+<select><option id="o1" style="height: 0cm;"></option></select>
+
+</body>
+</html>
diff --git a/widget/cocoa/crashtests/crashtests.list b/widget/cocoa/crashtests/crashtests.list
new file mode 100644
index 0000000000..0559273a43
--- /dev/null
+++ b/widget/cocoa/crashtests/crashtests.list
@@ -0,0 +1,11 @@
+skip-if(!cocoaWidget) load 373122-1.html # bug 1300017
+load 397209-1.html
+load 403296-1.xhtml
+load 419737-1.html
+load 435223-1.html
+load chrome://reftest/content/crashtests/widget/cocoa/crashtests/444260-1.xhtml
+load 444864-1.html
+load 449111-1.html
+load 460349-1.xhtml
+load 460387-1.html
+load 464589-1.html
diff --git a/widget/cocoa/cursors/arrowN.png b/widget/cocoa/cursors/arrowN.png
new file mode 100644
index 0000000000..c65924091a
--- /dev/null
+++ b/widget/cocoa/cursors/arrowN.png
diff --git a/widget/cocoa/cursors/arrowN@2x.png b/widget/cocoa/cursors/arrowN@2x.png
new file mode 100644
index 0000000000..496f856a1d
--- /dev/null
+++ b/widget/cocoa/cursors/arrowN@2x.png
diff --git a/widget/cocoa/cursors/arrowS.png b/widget/cocoa/cursors/arrowS.png
new file mode 100644
index 0000000000..3975e0837b
--- /dev/null
+++ b/widget/cocoa/cursors/arrowS.png
diff --git a/widget/cocoa/cursors/arrowS@2x.png b/widget/cocoa/cursors/arrowS@2x.png
new file mode 100644
index 0000000000..c7f817afd4
--- /dev/null
+++ b/widget/cocoa/cursors/arrowS@2x.png
diff --git a/widget/cocoa/cursors/cell.png b/widget/cocoa/cursors/cell.png
new file mode 100644
index 0000000000..1400d93f6e
--- /dev/null
+++ b/widget/cocoa/cursors/cell.png
diff --git a/widget/cocoa/cursors/cell@2x.png b/widget/cocoa/cursors/cell@2x.png
new file mode 100644
index 0000000000..5a1543b16b
--- /dev/null
+++ b/widget/cocoa/cursors/cell@2x.png
diff --git a/widget/cocoa/cursors/colResize.png b/widget/cocoa/cursors/colResize.png
new file mode 100644
index 0000000000..ef4b24936b
--- /dev/null
+++ b/widget/cocoa/cursors/colResize.png
diff --git a/widget/cocoa/cursors/colResize@2x.png b/widget/cocoa/cursors/colResize@2x.png
new file mode 100644
index 0000000000..d868ee6b57
--- /dev/null
+++ b/widget/cocoa/cursors/colResize@2x.png
diff --git a/widget/cocoa/cursors/help.png b/widget/cocoa/cursors/help.png
new file mode 100644
index 0000000000..7070b4b7bc
--- /dev/null
+++ b/widget/cocoa/cursors/help.png
diff --git a/widget/cocoa/cursors/help@2x.png b/widget/cocoa/cursors/help@2x.png
new file mode 100644
index 0000000000..7ddf157cd3
--- /dev/null
+++ b/widget/cocoa/cursors/help@2x.png
diff --git a/widget/cocoa/cursors/move.png b/widget/cocoa/cursors/move.png
new file mode 100644
index 0000000000..f6291500a4
--- /dev/null
+++ b/widget/cocoa/cursors/move.png
diff --git a/widget/cocoa/cursors/move@2x.png b/widget/cocoa/cursors/move@2x.png
new file mode 100644
index 0000000000..d094ce7a15
--- /dev/null
+++ b/widget/cocoa/cursors/move@2x.png
diff --git a/widget/cocoa/cursors/rowResize.png b/widget/cocoa/cursors/rowResize.png
new file mode 100644
index 0000000000..7f68a4007c
--- /dev/null
+++ b/widget/cocoa/cursors/rowResize.png
diff --git a/widget/cocoa/cursors/rowResize@2x.png b/widget/cocoa/cursors/rowResize@2x.png
new file mode 100644
index 0000000000..e0987a3b95
--- /dev/null
+++ b/widget/cocoa/cursors/rowResize@2x.png
diff --git a/widget/cocoa/cursors/sizeNE.png b/widget/cocoa/cursors/sizeNE.png
new file mode 100644
index 0000000000..fd71dea6ab
--- /dev/null
+++ b/widget/cocoa/cursors/sizeNE.png
diff --git a/widget/cocoa/cursors/sizeNE@2x.png b/widget/cocoa/cursors/sizeNE@2x.png
new file mode 100644
index 0000000000..400f5fe46f
--- /dev/null
+++ b/widget/cocoa/cursors/sizeNE@2x.png
diff --git a/widget/cocoa/cursors/sizeNESW.png b/widget/cocoa/cursors/sizeNESW.png
new file mode 100644
index 0000000000..5b2c300f4a
--- /dev/null
+++ b/widget/cocoa/cursors/sizeNESW.png
diff --git a/widget/cocoa/cursors/sizeNESW@2x.png b/widget/cocoa/cursors/sizeNESW@2x.png
new file mode 100644
index 0000000000..7299b98be1
--- /dev/null
+++ b/widget/cocoa/cursors/sizeNESW@2x.png
diff --git a/widget/cocoa/cursors/sizeNS.png b/widget/cocoa/cursors/sizeNS.png
new file mode 100644
index 0000000000..12b1602f14
--- /dev/null
+++ b/widget/cocoa/cursors/sizeNS.png
diff --git a/widget/cocoa/cursors/sizeNS@2x.png b/widget/cocoa/cursors/sizeNS@2x.png
new file mode 100644
index 0000000000..0dc7d15d75
--- /dev/null
+++ b/widget/cocoa/cursors/sizeNS@2x.png
diff --git a/widget/cocoa/cursors/sizeNW.png b/widget/cocoa/cursors/sizeNW.png
new file mode 100644
index 0000000000..57d270e0db
--- /dev/null
+++ b/widget/cocoa/cursors/sizeNW.png
diff --git a/widget/cocoa/cursors/sizeNW@2x.png b/widget/cocoa/cursors/sizeNW@2x.png
new file mode 100644
index 0000000000..312ee61ce4
--- /dev/null
+++ b/widget/cocoa/cursors/sizeNW@2x.png
diff --git a/widget/cocoa/cursors/sizeNWSE.png b/widget/cocoa/cursors/sizeNWSE.png
new file mode 100644
index 0000000000..d33c2486e4
--- /dev/null
+++ b/widget/cocoa/cursors/sizeNWSE.png
diff --git a/widget/cocoa/cursors/sizeNWSE@2x.png b/widget/cocoa/cursors/sizeNWSE@2x.png
new file mode 100644
index 0000000000..ecf1438265
--- /dev/null
+++ b/widget/cocoa/cursors/sizeNWSE@2x.png
diff --git a/widget/cocoa/cursors/sizeSE.png b/widget/cocoa/cursors/sizeSE.png
new file mode 100644
index 0000000000..1689138419
--- /dev/null
+++ b/widget/cocoa/cursors/sizeSE.png
diff --git a/widget/cocoa/cursors/sizeSE@2x.png b/widget/cocoa/cursors/sizeSE@2x.png
new file mode 100644
index 0000000000..7abce00fd5
--- /dev/null
+++ b/widget/cocoa/cursors/sizeSE@2x.png
diff --git a/widget/cocoa/cursors/sizeSW.png b/widget/cocoa/cursors/sizeSW.png
new file mode 100644
index 0000000000..5eadafb054
--- /dev/null
+++ b/widget/cocoa/cursors/sizeSW.png
diff --git a/widget/cocoa/cursors/sizeSW@2x.png b/widget/cocoa/cursors/sizeSW@2x.png
new file mode 100644
index 0000000000..b9ad862aa5
--- /dev/null
+++ b/widget/cocoa/cursors/sizeSW@2x.png
diff --git a/widget/cocoa/cursors/vtIBeam.png b/widget/cocoa/cursors/vtIBeam.png
new file mode 100644
index 0000000000..4609922319
--- /dev/null
+++ b/widget/cocoa/cursors/vtIBeam.png
diff --git a/widget/cocoa/cursors/vtIBeam@2x.png b/widget/cocoa/cursors/vtIBeam@2x.png
new file mode 100644
index 0000000000..a001362b04
--- /dev/null
+++ b/widget/cocoa/cursors/vtIBeam@2x.png
diff --git a/widget/cocoa/cursors/zoomIn.png b/widget/cocoa/cursors/zoomIn.png
new file mode 100644
index 0000000000..7ddfd4056d
--- /dev/null
+++ b/widget/cocoa/cursors/zoomIn.png
diff --git a/widget/cocoa/cursors/zoomIn@2x.png b/widget/cocoa/cursors/zoomIn@2x.png
new file mode 100644
index 0000000000..b1b844fa8c
--- /dev/null
+++ b/widget/cocoa/cursors/zoomIn@2x.png
diff --git a/widget/cocoa/cursors/zoomOut.png b/widget/cocoa/cursors/zoomOut.png
new file mode 100644
index 0000000000..ebacf25889
--- /dev/null
+++ b/widget/cocoa/cursors/zoomOut.png
diff --git a/widget/cocoa/cursors/zoomOut@2x.png b/widget/cocoa/cursors/zoomOut@2x.png
new file mode 100644
index 0000000000..5f84b767ec
--- /dev/null
+++ b/widget/cocoa/cursors/zoomOut@2x.png
diff --git a/widget/cocoa/docs/index.md b/widget/cocoa/docs/index.md
new file mode 100644
index 0000000000..cda6b2e349
--- /dev/null
+++ b/widget/cocoa/docs/index.md
@@ -0,0 +1,9 @@
+# Firefox on macOS
+
+```{toctree}
+:titlesonly:
+:maxdepth: 1
+:glob:
+
+*
+```
diff --git a/widget/cocoa/docs/macos-apis.md b/widget/cocoa/docs/macos-apis.md
new file mode 100644
index 0000000000..f0538dfb76
--- /dev/null
+++ b/widget/cocoa/docs/macos-apis.md
@@ -0,0 +1,188 @@
+# Using macOS APIs
+
+With each new macOS release, new APIs are added. Due to the wide range of platforms that Firefox runs on,
+and due to the [wide range of SDKs that we support building with](sdks.md#supported-sdks),
+using macOS APIs in Firefox requires some extra care.
+
+## Availability of APIs, and runtime checks
+
+First of all, if you use an API that is supported by all versions of macOS that Firefox runs on,
+i.e. 10.15 and above, then you don't need to worry about anything:
+The API declaration will be present in any of the supported SDKs, and you don't need any runtime checks.
+
+If you want to use a macOS API that was added after 10.15, then you have to have a runtime check.
+This requirement is completely independent of what SDK is being used for building.
+
+The runtime check [should have the following form](https://developer.apple.com/documentation/macos-release-notes/appkit-release-notes-for-macos-11?language=objc)
+(replace `11.0` with the appropriate version):
+
+```objc++
+if (@available(macOS 11.0, *)) {
+    // Code for macOS 11.0 or later
+} else {
+    // Code for versions earlier than 11.0.
+}
+```
+
+`@available` guards can be used in Objective-C(++) code.
+(In C++ code, you can use [these `nsCocoaFeatures` methods](https://searchfox.org/mozilla-central/rev/9ad88f80aeedcd3cd7d7f63be07f577861727054/widget/cocoa/nsCocoaFeatures.h#21-27) instead.)
+
+For each API, the API declarations in the SDK headers are annotated with `API_AVAILABLE` macros.
+For example, the definition of the `NSVisualEffectMaterial` enum looks like this:
+
+```objc++
+typedef NS_ENUM(NSInteger, NSVisualEffectMaterial) {
+    NSVisualEffectMaterialTitlebar = 3,
+    NSVisualEffectMaterialSelection = 4,
+    NSVisualEffectMaterialMenu API_AVAILABLE(macos(10.11)) = 5,
+   // [...]
+    NSVisualEffectMaterialSheet API_AVAILABLE(macos(10.14)) = 11,
+   // [...]
+} API_AVAILABLE(macos(10.10));
+```
+
+The compiler understands these annotations and makes sure that you wrap all uses of the annotated APIs
+in appropriate `@available` runtime checks.
+
+### Frameworks
+
+In some rare cases, you need functionality from frameworks that are not available on all supported macOS versions.
+Examples of this are `Metal.framework` (added in 10.11) and `MediaPlayer.framework` (added in 10.12.2).
+
+In that case, you can either `dlopen` your framework at runtime ([like we do for MediaPlayer](https://searchfox.org/mozilla-central/rev/9ad88f80aeedcd3cd7d7f63be07f577861727054/widget/cocoa/MediaPlayerWrapper.mm#21-27)),
+or you can [use `-weak_framework`](https://developer.apple.com/library/archive/documentation/MacOSX/Conceptual/BPFrameworks/Concepts/WeakLinking.html#//apple_ref/doc/uid/20002378-107026)
+[like we do for Metal](https://searchfox.org/mozilla-central/rev/9ad88f80aeedcd3cd7d7f63be07f577861727054/toolkit/library/moz.build#301-304):
+
+```python
+if CONFIG['OS_ARCH'] == 'Darwin':
+    OS_LIBS += [
+        # Link to Metal as required by the Metal gfx-hal backend
+        '-weak_framework Metal',
+    ]
+```
+
+## Using new APIs with old SDKs
+
+If you want to use an API that was introduced after 10.15, you now have one extra thing to worry about.
+In addition to the runtime check [described in the previous section](#using-macos-apis), you also
+have to jump through extra hoops in order to allow the build to succeed, because
+[our build target for Firefox has to remain at 10.15 in order for Firefox to run on macOS versions all the way down to macOS 10.15](sdks.md#supported-sdks).
+
+In order to make the compiler accept your code, you will need to copy some amount of the API declaration
+into your own code. Copy it from the newest recent SDK you can get your hands on.
+The exact procedure varies based on the type of API (enum, objc class, method, etc.),
+but the general approach looks like this:
+
+```objc++
+#if !defined(MAC_OS_VERSION_12_0) || MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_VERSION_12_0
+@interface NSScreen (NSScreen12_0)
+// https://developer.apple.com/documentation/appkit/nsscreen/3882821-safeareainsets?language=objc&changes=latest_major
+@property(readonly) NSEdgeInsets safeAreaInsets;
+@end
+#endif
+```
+
+See the [Supporting Multiple SDKs](sdks.md#supporting-multiple-sdks) docs for more information on the `MAC_OS_X_VERSION_MAX_ALLOWED` macro.
+
+Keep these three things in mind:
+
+ - Copy only what you need.
+ - Wrap your declaration in `MAC_OS_X_VERSION_MAX_ALLOWED` checks so that, if an SDK is used that
+   already contains these declarations, your declaration does not conflict with the declaration in the SDK.
+ - Include the `API_AVAILABLE` annotations so that the compiler can protect you from accidentally
+   calling the API on unsupported macOS versions.
+
+Our current code does not always follow the `API_AVAILABLE` advice, but it should.
+
+### Enum types and C structs
+
+If you need a new enum type or C struct, copy the entire type declaration and wrap it in the appropriate ifdefs. Example:
+
+```objc++
+#if !defined(MAC_OS_X_VERSION_10_12_2) || MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_12_2
+typedef NS_ENUM(NSUInteger, MPNowPlayingPlaybackState) {
+    MPNowPlayingPlaybackStateUnknown = 0,
+    MPNowPlayingPlaybackStatePlaying,
+    MPNowPlayingPlaybackStatePaused,
+    MPNowPlayingPlaybackStateStopped,
+    MPNowPlayingPlaybackStateInterrupted
+} MP_API(ios(11.0), tvos(11.0), macos(10.12.2), watchos(5.0));
+#endif
+```
+### New enum values for existing enum type
+
+If the enum type itself already exists, but gained a new value, define the value in an unnamed enum:
+
+```objc++
+#if !defined(MAC_OS_X_VERSION_10_12) || MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_12
+enum { NSVisualEffectMaterialSelection = 4 };
+#endif
+```
+
+(This is an example of an interesting case: `NSVisualEffectMaterialSelection` is available starting with
+macOS 10.10, but it's only defined in SDKs starting with the 10.12 SDK.)
+
+### Objective-C classes
+
+For a new Objective-C class, copy the entire `@interface` declaration and wrap it in the appropriate ifdefs.
+
+I haven't personally tested this. If this does not compile (or maybe link?), you can use the following workaround:
+
+ - Define your methods and properties as a category on `NSObject`.
+ - Look up the class at runtime using `NSClassFromString()`.
+ - If you need to create a subclass, do it at runtime using `objc_allocateClassPair` and `class_addMethod`.
+   [Here's an example of that.](https://searchfox.org/mozilla-central/rev/9ad88f80aeedcd3cd7d7f63be07f577861727054/widget/cocoa/VibrancyManager.mm#44-60)
+
+### Objective-C properties and methods on an existing class
+
+If an Objective-C class that already exists gains a new method or property, you can "add" it to the
+existing class declaration with the help of a [category](https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ProgrammingWithObjectiveC/CustomizingExistingClasses/CustomizingExistingClasses.html):
+
+```objc++
+@interface ExistingClass (YourMadeUpCategoryName)
+// methods and properties here
+@end
+```
+
+### Functions
+
+With free-standing functions I'm not entirely sure what to do.
+In theory, copying the declarations from the new SDK headers should work. Example:
+
+```objc++
+extern "C" {
+  __attribute__((warn_unused_result)) bool
+SecTrustEvaluateWithError(SecTrustRef trust, CFErrorRef _Nullable * _Nullable CF_RETURNS_RETAINED error)
+    API_AVAILABLE(macos(10.14), ios(12.0), tvos(12.0), watchos(5.0));
+
+  __nullable
+CFDataRef SecCertificateCopyNormalizedSubjectSequence(SecCertificateRef certificate)
+    __OSX_AVAILABLE_STARTING(__MAC_10_12_4, __IPHONE_10_3);
+}
+```
+
+I'm not sure what the linker or the dynamic linker do when the symbol is not available.
+Does this require [`__attribute__((weak_import))` annotations](https://developer.apple.com/library/archive/documentation/MacOSX/Conceptual/BPFrameworks/Concepts/WeakLinking.html#//apple_ref/doc/uid/20002378-107262-CJBJAEID)?
+
+And maybe this is where .tbd files in the SDK come in? So that the linker knows which symbols to allow?
+So then that part cannot be worked around by copying code from headers.
+
+Anyway, what always works is the pure runtime approach:
+
+ 1. Define types for the functions you need, but not the functions themselves.
+ 2. At runtime, look up the functions using `dlsym`.
+
+## Notes on Rust
+
+If you call macOS APIs from Rust code, you're kind of on your own. Apple does not provide any Rust
+"headers", so there isn't really an SDK to speak of. So you have to supply your own API declarations
+anyway, regardless of what SDK is being used for building.
+
+In a way, you're side-stepping some of the build time trouble. You don't need to worry about any
+`#ifdefs` because there are no system headers you could conflict with.
+
+On the other hand, you still need to worry about API availability at runtime.
+And in Rust, there are no [availability attributes](https://clang.llvm.org/docs/AttributeReference.html#availability)
+on your API declarations, and there are no
+[`@available` runtime check helpers](https://clang.llvm.org/docs/LanguageExtensions.html#objective-c-available),
+and the compiler cannot warn you if you call APIs outside of availability checks.
diff --git a/widget/cocoa/docs/sdks.md b/widget/cocoa/docs/sdks.md
new file mode 100644
index 0000000000..66565571bb
--- /dev/null
+++ b/widget/cocoa/docs/sdks.md
@@ -0,0 +1,227 @@
+# A primer on macOS SDKs
+
+## Overview
+
+A macOS SDK is an on-disk directory that contains header files and meta information for macOS APIs.
+Apple distributes SDKs as part of the Xcode app bundle. Each Xcode version comes with one macOS SDK,
+the SDK for the most recent released version of macOS at the time of the Xcode release.
+The SDK is located at `/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk`.
+
+Compiling Firefox for macOS requires a macOS SDK. The build system bootstraps an adequate SDK by
+default, but you can select a different SDK using the `mozconfig` option `--with-macos-sdk`:
+
+```text
+ac_add_options --with-macos-sdk=/Users/username/SDKs/MacOSX11.3.sdk
+```
+
+## Supported SDKs
+
+First off, Firefox runs on 10.15 and above. This is called the "minimum deployment target" and is
+independent of the SDK version.
+
+Our official Firefox builds compiled in CI (continuous integration) currently use the 13.3 SDK (last updated in [bug 1833998](https://bugzilla.mozilla.org/show_bug.cgi?id=1833998)). This is also the minimum supported SDK version for local builds.
+
+Compiling with different SDKs breaks from time to time. Such breakages should be [reported in Bugzilla](https://bugzilla.mozilla.org/enter_bug.cgi?blocked=mach-busted&bug_type=defect&cc=:spohl,:mstange&component=General&form_name=enter_bug&keywords=regression&op_sys=macOS&product=Firefox%20Build%20System&rep_platform=All) and fixed quickly.
+
+## Obtaining SDKs
+
+Sometimes you need an SDK that's different from the one in your Xcode.app, for example
+to check whether your code change breaks building with other SDKs, or to verify the
+runtime behavior with the SDK used for CI builds.
+
+The easy but slightly questionable way to obtain an SDK is to download it from a public github repo.
+
+Here's another option:
+
+ 1. Have your Apple ID login details ready, and bring enough time and patience for a 5GB download.
+ 2. Check [these tables in the Xcode wikipedia article](https://en.wikipedia.org/wiki/Xcode#Xcode_7.0_-_10.x_(since_Free_On-Device_Development))
+    and find an Xcode version that contains the SDK you need.
+ 3. Look up the Xcode version number on [xcodereleases.com](https://xcodereleases.com/) and click the Download link for it.
+ 4. Log in with your Apple ID. Then the download should start.
+ 5. Wait for the 5GB Xcode_*.xip download to finish.
+ 6. Open the downloaded xip file. This will extract the Xcode.app bundle.
+ 7. Inside the app bundle, the SDK is at `Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk`.
+
+## Effects of the SDK version
+
+An SDK only contains declarations of APIs. It does not contain the implementations for these APIs.
+
+The implementation of an API is provided by the OS that the app runs on. It is supplied at runtime,
+when your app starts up, by the dynamic linker. For example, the AppKit implementation comes
+from `/System/Library/Frameworks/AppKit.framework` from the OS that the app is run on, regardless
+of what SDK was used when compiling the app.
+
+In other words, building with a macOS SDK of a higher version doesn't magically make new APIs available
+when running on older versions of macOS. And, conversely, building with a lower macOS SDK doesn't limit
+which APIs you can use if your app is run on a newer version of macOS, assuming you manage to convince the
+compiler to accept your code.
+
+The SDK used for building an app determines three things:
+
+ 1. Whether your code compiles at all,
+ 2. which range of macOS versions your app can run on (available deployment targets), and
+ 3. certain aspects of runtime behavior.
+
+The first is straightforward: An SDK contains header files. If you call an API that's not declared
+anywhere - neither in a header file nor in your own code - then your compiler will emit an error.
+(Special case: Calling an unknown Objective-C method usually only emits a warning, not an error.)
+
+The second aspect, available deployment targets, is usually not worth worrying about:
+SDKs have large ranges of supported macOS deployment targets.
+For example, the 10.15 SDK supports running your app on macOS versions all the way back to 10.6.
+This information is written down in the SDK's `SDKSettings.plist`.
+
+The third aspect, varying runtime behavior, is perhaps the most insidious and surprising aspect, and is described
+in the next section.
+
+## Runtime differences based on macOS SDK version
+
+When a new version of macOS is released, existing APIs can change their behavior.
+These changes are usually described in the AppKit release notes:
+
+ - [macOS 10.15 release notes](https://developer.apple.com/documentation/macos_release_notes/macos_catalina_10_15_release_notes?language=objc)
+ - [macOS 10.14 AppKit release notes](https://developer.apple.com/documentation/macos_release_notes/macos_mojave_10_14_release_notes/appkit_release_notes_for_macos_10_14?language=objc)
+ - [macOS 10.13 AppKit release notes](https://developer.apple.com/library/archive/releasenotes/AppKit/RN-AppKit/)
+ - [macOS 10.12 and older AppKit release notes](https://developer.apple.com/library/archive/releasenotes/AppKit/RN-AppKitOlderNotes/)
+
+Sometimes, these differences in behavior have the potential to break existing apps. In those instances,
+Apple often provides the old (compatible) behavior until the app is re-built with the new SDK, expecting
+developers to update their apps so that they work with the new behavior, at the same time as
+they update to the new SDK.
+
+Here's an [example from the 10.13 release notes](https://developer.apple.com/library/archive/releasenotes/AppKit/RN-AppKit/#10_13NSCollectionView%20Responsive%20Scrolling):
+
+> Responsive Scrolling in NSCollectionViews is enabled only for apps linked on or after macOS 10.13.
+
+Here, "linked on or after macOS 10.13" means "linked against the macOS 10.13 SDK or newer".
+
+Apple's expectation is that you upgrade to the new macOS version when it is released, download a new
+Xcode version when it is released, synchronize these updates across the machines of all developers
+that work on your app, use the SDK in the newest Xcode to compile your app, and make changes to your
+app to be compatible with any behavior changes whenever you update Xcode.
+This expectation does not always match reality. It definitely doesn't match what we're doing with Firefox.
+
+For Firefox, SDK-dependent compatibility behaviors mean that developers who build Firefox locally
+can see different runtime behavior than the users of our CI builds, if they use a different SDK than
+the SDK used in CI.
+That is, unless we change the Firefox code so that it has the same behavior regardless of SDK version.
+Often this can be achieved by using APIs in a way that's more in line with the API's recommended use.
+
+For example, we've had cases of
+[broken placeholder text in search fields](https://bugzilla.mozilla.org/show_bug.cgi?id=1273106),
+[missing](https://bugzilla.mozilla.org/show_bug.cgi?id=941325) or [double-drawn focus rings](https://searchfox.org/mozilla-central/rev/9ad88f80aeedcd3cd7d7f63be07f577861727054/widget/cocoa/nsNativeThemeCocoa.mm#149-169),
+[a startup crash](https://bugzilla.mozilla.org/show_bug.cgi?id=1516437),
+[fully black windows](https://bugzilla.mozilla.org/show_bug.cgi?id=1494022),
+[fully gray windows](https://bugzilla.mozilla.org/show_bug.cgi?id=1576113#c4),
+[broken vibrancy](https://bugzilla.mozilla.org/show_bug.cgi?id=1475694), and
+[broken colors in dark mode](https://bugzilla.mozilla.org/show_bug.cgi?id=1578917).
+
+In most of these cases, the breakage was either very minor, or it was caused by Firefox doing things
+that were explicitly discouraged, like creating unexpected NSView hierarchies, or relying on unspecified
+implementation details. (With one exception: In 10.14, HiDPI-aware `NSOpenGLContext` rendering in
+layer-backed windows simply broke.)
+
+And in all of these cases, it was the SDK-dependent compatibility behavior that protected our users from being
+exposed to the breakage. Our CI builds continued to work because they were built with an older SDK.
+
+We have addressed all known cases of breakage when building Firefox with newer SDKs.
+I am not aware of any current instances of this problem as of this writing (June 2020).
+
+For more information about how these compatibility tricks work,
+read the [Overriding SDK-dependent runtime behavior](#overriding-sdk-dependent-runtime-behavior) section.
+
+## Supporting multiple SDKs
+
+As described under [Supported SDKs](#supported-sdks), Firefox can be built with a wide variety of SDK versions.
+
+This ability comes at the cost of some manual labor; it requires some well-placed `#ifdefs` and
+copying of header definitions.
+
+Every SDK defines the macro `MAC_OS_X_VERSION_MAX_ALLOWED` with a value that matches the SDK version,
+in the SDK's `AvailabilityMacros.h` header. This header also defines version constants like `MAC_OS_X_VERSION_10_12`.
+For example, I have a version of the 10.12 SDK which contains the line
+
+```cpp
+#define MAC_OS_X_VERSION_MAX_ALLOWED MAC_OS_X_VERSION_10_12_4
+```
+
+The name `MAC_OS_X_VERSION_MAX_ALLOWED` is rather misleading; a better name would be
+`MAC_OS_X_VERSION_MAX_KNOWN_BY_SDK`. Compiling with an old SDK *does not* prevent apps from running
+on newer versions of macOS.
+
+With the help of the `MAC_OS_X_VERSION_MAX_ALLOWED` macro, we can make our code adapt to the SDK that's
+being used. Here's [an example](https://searchfox.org/mozilla-central/rev/9ad88f80aeedcd3cd7d7f63be07f577861727054/toolkit/xre/MacApplicationDelegate.mm#345-351) where the 10.14 SDK changed the signature of
+[an `NSApplicationDelegate` method](https://developer.apple.com/documentation/appkit/nsapplicationdelegate/1428471-application?language=objc):
+
+```objc++
+- (BOOL)application:(NSApplication*)application
+    continueUserActivity:(NSUserActivity*)userActivity
+#if defined(MAC_OS_X_VERSION_10_14) && MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_14
+      restorationHandler:(void (^)(NSArray<id<NSUserActivityRestoring>>*))restorationHandler {
+#else
+      restorationHandler:(void (^)(NSArray*))restorationHandler {
+#endif
+  ...
+}
+```
+
+We can also use this macro to supply missing API definitions in such a way that
+they don't conflict with the definitions from the SDK.
+This is described in the "Using macOS APIs" document, under [Using new APIs with old SDKs](./macos-apis.md#using-new-apis-with-old-sdks).
+
+## Overriding SDK-dependent runtime behavior
+
+This section contains some more details on the compatibility tricks that cause different runtime
+behavior dependent on the SDK, as described in
+[Runtime differences based on macOS SDK version](#runtime-differences-based-on-macos-sdk-version).
+
+### How it works
+
+AppKit is the one system framework I know of that employs these tricks. Let's explore how AppKit makes this work,
+by going back to the [NSCollectionView example](https://developer.apple.com/library/archive/releasenotes/AppKit/RN-AppKit/#10_13NSCollectionView%20Responsive%20Scrolling) from above:
+
+> Responsive Scrolling in NSCollectionViews is enabled only for apps linked on or after macOS 10.13.
+
+For each of these SDK-dependent behavior differences, both the old and the new behavior are implemented
+in the version of AppKit that ships with the new macOS version.
+At runtime, AppKit selects one of the behaviors based on the SDK version, with a call to
+`_CFExecutableLinkedOnOrAfter()`. This call checks the SDK version of the main executable of the
+process that's running AppKit code; in our case that's the `firefox` or `plugin-container` executable.
+The SDK version is stored in the mach-o headers of the executable by the linker.
+
+One interesting design aspect of AppKit's compatibility tricks is the fact that most of these behavior differences
+can be toggled with a "user default" preference.
+For example, the "responsive scrolling in NSCollectionViews" behavior change can be controlled with
+a user default with the name "NSCollectionViewPrefetchingEnabled".
+The SDK check only happens if "NSCollectionViewPrefetchingEnabled" is not set to either YES or NO.
+
+More precisely, this example works as follows:
+
+ - `-[NSCollectionView prepareContentInRect:]` is the function that supports both the old and the new behavior.
+ - It calls `_NSGetBoolAppConfig` for the value "NSCollectionViewPrefetchingEnabled", and also supplies a "default
+   value function".
+ - If the user default is not set, the default value function is called. This function has the name
+   `NSCollectionViewPrefetchingEnabledDefaultValueFunction`.
+ - `NSCollectionViewPrefetchingEnabledDefaultValueFunction` calls `_CFExecutableLinkedOnOrAfter(13)`.
+
+You can find many similar toggles if you list the AppKit symbols that end in `DefaultValueFunction`,
+for example by executing `nm /System/Library/Frameworks/AppKit.framework/AppKit | grep DefaultValueFunction`.
+
+### Overriding SDK-dependent runtime behavior
+
+You can set these preferences programmatically, in a way that `_NSGetBoolAppConfig()` can pick them up,
+for example with [`registerDefaults`](https://developer.apple.com/documentation/foundation/nsuserdefaults/1417065-registerdefaults?language=objc)
+or like this:
+
+```objc++
+[[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"NSViewAllowsRootLayerBacking"];
+```
+
+The AppKit release notes mention this ability but ask for it to only be used for debugging purposes:
+
+> In some cases, we provide defaults (preferences) settings which can be used to get the old or new behavior,
+> independent of what system an application was built against. Often these preferences are provided for
+> debugging purposes only; in some cases the preferences can be used to globally modify the behavior
+> of an application by registering the values (do it somewhere very early, with `-[NSUserDefaults registerDefaults:]`).
+
+It's interesting that they mention this at all because, as far as I can tell, none of these values are documented.
diff --git a/widget/cocoa/metrics.yaml b/widget/cocoa/metrics.yaml
new file mode 100644
index 0000000000..d354da069e
--- /dev/null
+++ b/widget/cocoa/metrics.yaml
@@ -0,0 +1,11 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Adding a new metric? We have docs for that!
+# https://firefox-source-docs.mozilla.org/toolkit/components/glean/user/new_definitions_file.html
+
+---
+$schema: moz://mozilla.org/schemas/glean/metrics/2-0-0
+$tags:
+  - 'Core :: Widget: Cocoa'
diff --git a/widget/cocoa/moz.build b/widget/cocoa/moz.build
new file mode 100644
index 0000000000..ebee9439e0
--- /dev/null
+++ b/widget/cocoa/moz.build
@@ -0,0 +1,181 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+    SCHEDULES.exclusive = ["macosx"]
+
+with Files("*TextInput*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+XPIDL_SOURCES += [
+    "nsPIWidgetCocoa.idl",
+]
+
+XPIDL_MODULE = "widget_cocoa"
+
+EXPORTS += [
+    "CFTypeRefPtr.h",
+    "DesktopBackgroundImage.h",
+    "MediaHardwareKeysEventSourceMac.h",
+    "MediaHardwareKeysEventSourceMacMediaCenter.h",
+    "mozView.h",
+    "nsBidiKeyboard.h",
+    "nsChangeObserver.h",
+    "nsCocoaFeatures.h",
+    "nsCocoaUtils.h",
+]
+
+UNIFIED_SOURCES += [
+    "AppearanceOverride.mm",
+    "GfxInfo.mm",
+    "MOZIconHelper.mm",
+    "MOZMenuOpeningCoordinator.mm",
+    "NativeKeyBindings.mm",
+    "NativeMenuMac.mm",
+    "NativeMenuSupport.mm",
+    "nsAppShell.mm",
+    "nsBidiKeyboard.mm",
+    "nsCocoaFeatures.mm",
+    "nsCocoaUtils.mm",
+    "nsCocoaWindow.mm",
+    "nsColorPicker.mm",
+    "nsCursorManager.mm",
+    "nsDeviceContextSpecX.mm",
+    "nsFilePicker.mm",
+    "nsLookAndFeel.mm",
+    "nsMacCursor.mm",
+    "nsMacDockSupport.mm",
+    "nsMacFinderProgress.mm",
+    "nsMacSharingService.mm",
+    "nsMacUserActivityUpdater.mm",
+    "nsMacWebAppUtils.mm",
+    "nsMenuBarX.mm",
+    "nsMenuGroupOwnerX.mm",
+    "nsMenuItemIconX.mm",
+    "nsMenuItemX.mm",
+    "nsMenuUtilsX.mm",
+    "nsMenuX.mm",
+    "nsPrintDialogX.mm",
+    "nsPrintSettingsServiceX.mm",
+    "nsPrintSettingsX.mm",
+    "nsSound.mm",
+    "nsStandaloneNativeMenu.mm",
+    "nsSystemStatusBarCocoa.mm",
+    "nsToolkit.mm",
+    "nsTouchBar.mm",
+    "nsTouchBarInput.mm",
+    "nsTouchBarInputIcon.mm",
+    "nsTouchBarUpdater.mm",
+    "nsUserIdleServiceX.mm",
+    "nsWidgetFactory.mm",
+    "nsWindowMap.mm",
+    "OSXNotificationCenter.mm",
+    "ScreenHelperCocoa.mm",
+    "TextInputHandler.mm",
+    "TextRecognition.mm",
+    "VibrancyManager.mm",
+    "ViewRegion.mm",
+    "WidgetTraceEvent.mm",
+]
+
+# These files cannot be built in unified mode because they cause symbol conflicts
+SOURCES += [
+    "DesktopBackgroundImage.mm",
+    "MediaHardwareKeysEventSourceMac.mm",
+    "MediaHardwareKeysEventSourceMacMediaCenter.mm",
+    "MediaKeysEventSourceFactory.cpp",
+    "nsChildView.mm",
+    "nsClipboard.mm",
+    "nsDragService.mm",
+    "nsNativeThemeCocoa.mm",
+]
+
+if not CONFIG["RELEASE_OR_BETA"] or CONFIG["MOZ_DEBUG"]:
+    SOURCES += [
+        "nsSandboxViolationSink.mm",
+    ]
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
+LOCAL_INCLUDES += [
+    "/dom/events",
+    "/dom/media/platforms/apple",
+    "/layout/base",
+    "/layout/forms",
+    "/layout/generic",
+    "/layout/style",
+    "/layout/xul",
+    "/widget",
+    "/widget/headless",
+]
+
+if CONFIG["MOZ_ENABLE_SKIA_PDF"]:
+    # Skia includes because widget code includes PrintTargetSkPDF.h, and that
+    # includes skia headers.
+    LOCAL_INCLUDES += CONFIG["SKIA_INCLUDES"]
+
+RESOURCE_FILES.cursors += [
+    "cursors/arrowN.png",
+    "cursors/arrowN@2x.png",
+    "cursors/arrowS.png",
+    "cursors/arrowS@2x.png",
+    "cursors/cell.png",
+    "cursors/cell@2x.png",
+    "cursors/colResize.png",
+    "cursors/colResize@2x.png",
+    "cursors/help.png",
+    "cursors/help@2x.png",
+    "cursors/move.png",
+    "cursors/move@2x.png",
+    "cursors/rowResize.png",
+    "cursors/rowResize@2x.png",
+    "cursors/sizeNE.png",
+    "cursors/sizeNE@2x.png",
+    "cursors/sizeNESW.png",
+    "cursors/sizeNESW@2x.png",
+    "cursors/sizeNS.png",
+    "cursors/sizeNS@2x.png",
+    "cursors/sizeNW.png",
+    "cursors/sizeNW@2x.png",
+    "cursors/sizeNWSE.png",
+    "cursors/sizeNWSE@2x.png",
+    "cursors/sizeSE.png",
+    "cursors/sizeSE@2x.png",
+    "cursors/sizeSW.png",
+    "cursors/sizeSW@2x.png",
+    "cursors/vtIBeam.png",
+    "cursors/vtIBeam@2x.png",
+    "cursors/zoomIn.png",
+    "cursors/zoomIn@2x.png",
+    "cursors/zoomOut.png",
+    "cursors/zoomOut@2x.png",
+]
+
+# These resources go in $(DIST)/bin/res/MainMenu.nib, but we can't use a magic
+# RESOURCE_FILES.MainMenu.nib attribute, since that would put the files in
+# $(DIST)/bin/res/MainMenu/nib. Instead, we call __setattr__ directly to create
+# an attribute with the correct name.
+RESOURCE_FILES.__setattr__(
+    "MainMenu.nib",
+    [
+        "resources/MainMenu.nib/classes.nib",
+        "resources/MainMenu.nib/info.nib",
+        "resources/MainMenu.nib/keyedobjects.nib",
+    ],
+)
+
+OS_LIBS += [
+    "-framework IOSurface",
+    "-framework Vision",
+]
+
+SPHINX_TREES["/widget/cocoa"] = "docs"
diff --git a/widget/cocoa/mozView.h b/widget/cocoa/mozView.h
new file mode 100644
index 0000000000..deb719254e
--- /dev/null
+++ b/widget/cocoa/mozView.h
@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozView_h_
+#define mozView_h_
+
+#undef DARWIN
+#import <Cocoa/Cocoa.h>
+class nsIWidget;
+
+namespace mozilla {
+namespace widget {
+class TextInputHandler;
+}  // namespace widget
+}  // namespace mozilla
+
+// A protocol with some of the methods that ChildView implements. In the distant
+// past, this protocol was used by embedders: They would create their own NSView
+// subclass, implement mozView on it, and then embed a Gecko ChildView by adding
+// it as a subview of this view. This scenario no longer exists.
+// Now this protocol is mostly just used by TextInputHandler and mozAccessible
+// in order to communicate with ChildView without seeing the entire ChildView
+// interface definition.
+@protocol mozView
+
+// aHandler is Gecko's default text input handler:  It implements the
+// NSTextInput protocol to handle key events.  Don't make aHandler a
+// strong reference -- that causes a memory leak.
+- (void)installTextInputHandler:(mozilla::widget::TextInputHandler*)aHandler;
+- (void)uninstallTextInputHandler;
+
+// access the nsIWidget associated with this view. DOES NOT ADDREF.
+- (nsIWidget*)widget;
+
+// called when our corresponding Gecko view goes away
+- (void)widgetDestroyed;
+
+- (BOOL)isDragInProgress;
+
+// Checks whether the view is first responder or not
+- (BOOL)isFirstResponder;
+
+// Call when you dispatch an event which may cause to open context menu.
+- (void)maybeInitContextMenuTracking;
+
+@end
+
+// An informal protocol implemented by the NSWindow of the host application.
+//
+// It's used to prevent re-entrant calls to -makeKeyAndOrderFront: when gecko
+// focus/activate events propagate out to the embedder's
+// nsIEmbeddingSiteWindow::SetFocus implementation.
+@interface NSObject (mozWindow)
+
+- (BOOL)suppressMakeKeyFront;
+- (void)setSuppressMakeKeyFront:(BOOL)inSuppress;
+
+@end
+
+#endif  // mozView_h_
diff --git a/widget/cocoa/nsAppShell.h b/widget/cocoa/nsAppShell.h
new file mode 100644
index 0000000000..921a166436
--- /dev/null
+++ b/widget/cocoa/nsAppShell.h
@@ -0,0 +1,96 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Runs the main native Cocoa run loop, interrupting it as needed to process
+ * Gecko events.
+ */
+
+#ifndef nsAppShell_h_
+#define nsAppShell_h_
+
+#import <AppKit/NSApplication.h>
+
+#include "nsBaseAppShell.h"
+#include "nsTArray.h"
+
+class ProfilingStack;
+
+namespace mozilla {
+class nsAvailableMemoryWatcherBase;
+}
+
+// GeckoNSApplication
+//
+// Subclass of NSApplication for filtering out certain events.
+@interface GeckoNSApplication : NSApplication {
+}
+@property(readonly) BOOL didLaunch;
+@end
+
+@class AppShellDelegate;
+
+class nsAppShell : public nsBaseAppShell {
+ public:
+  NS_IMETHOD ResumeNative(void) override;
+
+  nsAppShell();
+
+  nsresult Init();
+
+  NS_IMETHOD Run(void) override;
+  NS_IMETHOD Exit(void) override;
+  NS_IMETHOD OnProcessNextEvent(nsIThreadInternal* aThread,
+                                bool aMayWait) override;
+  NS_IMETHOD AfterProcessNextEvent(nsIThreadInternal* aThread,
+                                   bool aEventWasProcessed) override;
+
+  void OnRunLoopActivityChanged(CFRunLoopActivity aActivity);
+
+  // public only to be visible to Objective-C code that must call it
+  void WillTerminate();
+
+  static void OnMemoryPressureChanged(
+      dispatch_source_memorypressure_flags_t aPressureLevel);
+
+ protected:
+  virtual ~nsAppShell();
+
+  virtual void ScheduleNativeEventCallback() override;
+  virtual bool ProcessNextNativeEvent(bool aMayWait) override;
+
+  void InitMemoryPressureObserver();
+
+  static void ProcessGeckoEvents(void* aInfo);
+
+ protected:
+  CFMutableArrayRef mAutoreleasePools;
+
+  AppShellDelegate* mDelegate;
+  CFRunLoopRef mCFRunLoop;
+  CFRunLoopSourceRef mCFRunLoopSource;
+
+  // An observer for the profiler that is notified when the event loop enters
+  // and exits the waiting state.
+  CFRunLoopObserverRef mCFRunLoopObserver;
+
+  // Non-null while the native event loop is in the waiting state.
+  ProfilingStack* mProfilingStackWhileWaiting = nullptr;
+
+  // For getting notifications from the OS about memory pressure state changes.
+  dispatch_source_t mMemoryPressureSource = nullptr;
+
+  bool mRunningEventLoop;
+  bool mStarted;
+  bool mTerminated;
+  bool mSkippedNativeCallback;
+  bool mRunningCocoaEmbedded;
+
+  int32_t mNativeEventCallbackDepth;
+  // Can be set from different threads, so must be modified atomically
+  int32_t mNativeEventScheduledDepth;
+};
+
+#endif  // nsAppShell_h_
diff --git a/widget/cocoa/nsAppShell.mm b/widget/cocoa/nsAppShell.mm
new file mode 100644
index 0000000000..3dbc527f65
--- /dev/null
+++ b/widget/cocoa/nsAppShell.mm
@@ -0,0 +1,1154 @@
+/* -*- tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Runs the main native Cocoa run loop, interrupting it as needed to process
+ * Gecko events.
+ */
+
+#import <Cocoa/Cocoa.h>
+
+#include <dlfcn.h>
+
+#include "mozilla/AvailableMemoryWatcher.h"
+#include "CustomCocoaEvents.h"
+#include "mozilla/WidgetTraceEvent.h"
+#include "nsAppShell.h"
+#include "gfxPlatform.h"
+#include "nsCOMPtr.h"
+#include "nsIFile.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsString.h"
+#include "nsIRollupListener.h"
+#include "nsIWidget.h"
+#include "nsMemoryPressure.h"
+#include "nsThreadUtils.h"
+#include "nsServiceManagerUtils.h"
+#include "nsObjCExceptions.h"
+#include "nsCocoaUtils.h"
+#include "nsCocoaFeatures.h"
+#include "nsChildView.h"
+#include "nsToolkit.h"
+#include "TextInputHandler.h"
+#include "mozilla/BackgroundHangMonitor.h"
+#include "ScreenHelperCocoa.h"
+#include "mozilla/Hal.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/ProfilerThreadSleep.h"
+#include "mozilla/widget/ScreenManager.h"
+#include "HeadlessScreenHelper.h"
+#include "MOZMenuOpeningCoordinator.h"
+#include "pratom.h"
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
+#  include "nsSandboxViolationSink.h"
+#endif
+
+#include <IOKit/pwr_mgt/IOPMLib.h>
+#include "nsIDOMWakeLockListener.h"
+#include "nsIPowerManagerService.h"
+
+#include "nsIObserverService.h"
+#include "mozilla/Services.h"
+#include "mozilla/StaticPrefs_widget.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+#define WAKE_LOCK_LOG(...) \
+  MOZ_LOG(gMacWakeLockLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+static mozilla::LazyLogModule gMacWakeLockLog("MacWakeLock");
+
+// A wake lock listener that disables screen saver when requested by
+// Gecko. For example when we're playing video in a foreground tab we
+// don't want the screen saver to turn on.
+
+class MacWakeLockListener final : public nsIDOMMozWakeLockListener {
+ public:
+  NS_DECL_ISUPPORTS;
+
+ private:
+  ~MacWakeLockListener() {}
+
+  IOPMAssertionID mAssertionNoDisplaySleepID = kIOPMNullAssertionID;
+  IOPMAssertionID mAssertionNoIdleSleepID = kIOPMNullAssertionID;
+
+  NS_IMETHOD Callback(const nsAString& aTopic,
+                      const nsAString& aState) override {
+    if (!aTopic.EqualsASCII("screen") && !aTopic.EqualsASCII("audio-playing") &&
+        !aTopic.EqualsASCII("video-playing")) {
+      return NS_OK;
+    }
+
+    // we should still hold the lock for background audio.
+    if (aTopic.EqualsASCII("audio-playing") &&
+        aState.EqualsASCII("locked-background")) {
+      WAKE_LOCK_LOG("keep audio playing even in background");
+      return NS_OK;
+    }
+
+    bool shouldKeepDisplayOn =
+        aTopic.EqualsASCII("screen") || aTopic.EqualsASCII("video-playing");
+    CFStringRef assertionType = shouldKeepDisplayOn
+                                    ? kIOPMAssertionTypeNoDisplaySleep
+                                    : kIOPMAssertionTypeNoIdleSleep;
+    IOPMAssertionID& assertionId = shouldKeepDisplayOn
+                                       ? mAssertionNoDisplaySleepID
+                                       : mAssertionNoIdleSleepID;
+    WAKE_LOCK_LOG("topic=%s, state=%s, shouldKeepDisplayOn=%d",
+                  NS_ConvertUTF16toUTF8(aTopic).get(),
+                  NS_ConvertUTF16toUTF8(aState).get(), shouldKeepDisplayOn);
+
+    // Note the wake lock code ensures that we're not sent duplicate
+    // "locked-foreground" notifications when multiple wake locks are held.
+    if (aState.EqualsASCII("locked-foreground")) {
+      if (assertionId != kIOPMNullAssertionID) {
+        WAKE_LOCK_LOG("already has a lock");
+        return NS_OK;
+      }
+      // Prevent screen saver.
+      CFStringRef cf_topic = ::CFStringCreateWithCharacters(
+          kCFAllocatorDefault, reinterpret_cast<const UniChar*>(aTopic.Data()),
+          aTopic.Length());
+      IOReturn success = ::IOPMAssertionCreateWithName(
+          assertionType, kIOPMAssertionLevelOn, cf_topic, &assertionId);
+      CFRelease(cf_topic);
+      if (success != kIOReturnSuccess) {
+        WAKE_LOCK_LOG("failed to disable screensaver");
+      }
+      WAKE_LOCK_LOG("create screensaver");
+    } else {
+      // Re-enable screen saver.
+      if (assertionId != kIOPMNullAssertionID) {
+        IOReturn result = ::IOPMAssertionRelease(assertionId);
+        if (result != kIOReturnSuccess) {
+          WAKE_LOCK_LOG("failed to release screensaver");
+        }
+        WAKE_LOCK_LOG("Release screensaver");
+        assertionId = kIOPMNullAssertionID;
+      }
+    }
+    return NS_OK;
+  }
+};  // MacWakeLockListener
+
+// defined in nsCocoaWindow.mm
+extern int32_t gXULModalLevel;
+
+static bool gAppShellMethodsSwizzled = false;
+
+void OnUncaughtException(NSException* aException) {
+  nsObjCExceptionLog(aException);
+  MOZ_CRASH(
+      "Uncaught Objective C exception from NSSetUncaughtExceptionHandler");
+}
+
+@implementation GeckoNSApplication
+
+// Load is called very early during startup, when the Objective C runtime loads
+// this class.
++ (void)load {
+  NSSetUncaughtExceptionHandler(OnUncaughtException);
+}
+
+// This method is called from NSDefaultTopLevelErrorHandler, which is invoked
+// when an Objective C exception propagates up into the native event loop. It is
+// possible that it is also called in other cases.
+- (void)reportException:(NSException*)aException {
+  if (ShouldIgnoreObjCException(aException)) {
+    return;
+  }
+
+  nsObjCExceptionLog(aException);
+
+#ifdef NIGHTLY_BUILD
+  MOZ_CRASH("Uncaught Objective C exception from -[GeckoNSApplication "
+            "reportException:]");
+#endif
+}
+
+- (void)run {
+  _didLaunch = YES;
+  [super run];
+}
+
+- (void)sendEvent:(NSEvent*)anEvent {
+  mozilla::BackgroundHangMonitor().NotifyActivity();
+
+  if ([anEvent type] == NSEventTypeApplicationDefined &&
+      [anEvent subtype] == kEventSubtypeTrace) {
+    mozilla::SignalTracerThread();
+    return;
+  }
+  [super sendEvent:anEvent];
+}
+
+- (NSEvent*)nextEventMatchingMask:(NSEventMask)mask
+                        untilDate:(NSDate*)expiration
+                           inMode:(NSString*)mode
+                          dequeue:(BOOL)flag {
+  MOZ_ASSERT([NSApp didLaunch]);
+  if (expiration) {
+    mozilla::BackgroundHangMonitor().NotifyWait();
+  }
+  NSEvent* nextEvent = [super nextEventMatchingMask:mask
+                                          untilDate:expiration
+                                             inMode:mode
+                                            dequeue:flag];
+  if (expiration) {
+    mozilla::BackgroundHangMonitor().NotifyActivity();
+  }
+  return nextEvent;
+}
+
+@end
+
+// AppShellDelegate
+//
+// Cocoa bridge class.  An object of this class is registered to receive
+// notifications.
+//
+@interface AppShellDelegate : NSObject {
+ @private
+  nsAppShell* mAppShell;
+}
+
+- (id)initWithAppShell:(nsAppShell*)aAppShell;
+- (void)applicationWillTerminate:(NSNotification*)aNotification;
+@end
+
+// nsAppShell implementation
+
+NS_IMETHODIMP
+nsAppShell::ResumeNative(void) {
+  nsresult retval = nsBaseAppShell::ResumeNative();
+  if (NS_SUCCEEDED(retval) && (mSuspendNativeCount == 0) &&
+      mSkippedNativeCallback) {
+    mSkippedNativeCallback = false;
+    ScheduleNativeEventCallback();
+  }
+  return retval;
+}
+
+nsAppShell::nsAppShell()
+    : mAutoreleasePools(nullptr),
+      mDelegate(nullptr),
+      mCFRunLoop(NULL),
+      mCFRunLoopSource(NULL),
+      mRunningEventLoop(false),
+      mStarted(false),
+      mTerminated(false),
+      mSkippedNativeCallback(false),
+      mNativeEventCallbackDepth(0),
+      mNativeEventScheduledDepth(0) {
+  // A Cocoa event loop is running here if (and only if) we've been embedded
+  // by a Cocoa app.
+  mRunningCocoaEmbedded = [NSApp isRunning] ? true : false;
+}
+
+nsAppShell::~nsAppShell() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  hal::Shutdown();
+
+  if (mMemoryPressureSource) {
+    dispatch_release(mMemoryPressureSource);
+    mMemoryPressureSource = nullptr;
+  }
+
+  if (mCFRunLoop) {
+    if (mCFRunLoopSource) {
+      ::CFRunLoopRemoveSource(mCFRunLoop, mCFRunLoopSource,
+                              kCFRunLoopCommonModes);
+      ::CFRelease(mCFRunLoopSource);
+    }
+    if (mCFRunLoopObserver) {
+      ::CFRunLoopRemoveObserver(mCFRunLoop, mCFRunLoopObserver,
+                                kCFRunLoopCommonModes);
+      ::CFRelease(mCFRunLoopObserver);
+    }
+    ::CFRelease(mCFRunLoop);
+  }
+
+  if (mAutoreleasePools) {
+    NS_ASSERTION(::CFArrayGetCount(mAutoreleasePools) == 0,
+                 "nsAppShell destroyed without popping all autorelease pools");
+    ::CFRelease(mAutoreleasePools);
+  }
+
+  [mDelegate release];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK
+}
+
+NS_IMPL_ISUPPORTS(MacWakeLockListener, nsIDOMMozWakeLockListener)
+mozilla::StaticRefPtr<MacWakeLockListener> sWakeLockListener;
+
+static void AddScreenWakeLockListener() {
+  nsCOMPtr<nsIPowerManagerService> sPowerManagerService =
+      do_GetService(POWERMANAGERSERVICE_CONTRACTID);
+  if (sPowerManagerService) {
+    sWakeLockListener = new MacWakeLockListener();
+    sPowerManagerService->AddWakeLockListener(sWakeLockListener);
+  } else {
+    NS_WARNING(
+        "Failed to retrieve PowerManagerService, wakelocks will be broken!");
+  }
+}
+
+static void RemoveScreenWakeLockListener() {
+  nsCOMPtr<nsIPowerManagerService> sPowerManagerService =
+      do_GetService(POWERMANAGERSERVICE_CONTRACTID);
+  if (sPowerManagerService) {
+    sPowerManagerService->RemoveWakeLockListener(sWakeLockListener);
+    sPowerManagerService = nullptr;
+    sWakeLockListener = nullptr;
+  }
+}
+
+void RunLoopObserverCallback(CFRunLoopObserverRef aObserver,
+                             CFRunLoopActivity aActivity, void* aInfo) {
+  static_cast<nsAppShell*>(aInfo)->OnRunLoopActivityChanged(aActivity);
+}
+
+void nsAppShell::OnRunLoopActivityChanged(CFRunLoopActivity aActivity) {
+  if (aActivity == kCFRunLoopBeforeWaiting) {
+    mozilla::BackgroundHangMonitor().NotifyWait();
+  }
+
+  // When the event loop is in its waiting state, we would like the profiler to
+  // know that the thread is idle. The usual way to notify the profiler of
+  // idleness would be to place a profiler label frame with the IDLE category on
+  // the stack, for the duration of the function that does the waiting. However,
+  // since macOS uses an event loop model where "the event loop calls you", we
+  // do not control the function that does the waiting; the waiting happens
+  // inside CFRunLoop code. Instead, the run loop notifies us when it enters and
+  // exits the waiting state, by calling this function. So we do not have a
+  // function under our control that stays on the stack for the duration of the
+  // wait. So, rather than putting an AutoProfilerLabel on the stack, we will
+  // manually push and pop the label frame here. The location in the stack where
+  // this label frame is inserted is somewhat arbitrary. In practice, the label
+  // frame will be at the very tip of the stack, looking like it's "inside" the
+  // mach_msg_trap wait function.
+  if (aActivity == kCFRunLoopBeforeWaiting) {
+    using ThreadRegistration = mozilla::profiler::ThreadRegistration;
+    ThreadRegistration::WithOnThreadRef(
+        [&](ThreadRegistration::OnThreadRef aOnThreadRef) {
+          ProfilingStack& profilingStack =
+              aOnThreadRef.UnlockedConstReaderAndAtomicRWRef()
+                  .ProfilingStackRef();
+          mProfilingStackWhileWaiting = &profilingStack;
+          uint8_t variableOnStack = 0;
+          profilingStack.pushLabelFrame("Native event loop idle", nullptr,
+                                        &variableOnStack,
+                                        JS::ProfilingCategoryPair::IDLE, 0);
+          profiler_thread_sleep();
+        });
+  } else {
+    if (mProfilingStackWhileWaiting) {
+      mProfilingStackWhileWaiting->pop();
+      mProfilingStackWhileWaiting = nullptr;
+      profiler_thread_wake();
+    }
+  }
+}
+
+// Init
+//
+// Loads the nib (see bug 316076c21) and sets up the CFRunLoopSource used to
+// interrupt the main native run loop.
+//
+// public
+nsresult nsAppShell::Init() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // No event loop is running yet (unless an embedding app that uses
+  // NSApplicationMain() is running).
+  NSAutoreleasePool* localPool = [[NSAutoreleasePool alloc] init];
+
+  char* mozAppNoDock = PR_GetEnv("MOZ_APP_NO_DOCK");
+  if (mozAppNoDock && strcmp(mozAppNoDock, "") != 0) {
+    [NSApp setActivationPolicy:NSApplicationActivationPolicyAccessory];
+  }
+
+  // mAutoreleasePools is used as a stack of NSAutoreleasePool objects created
+  // by |this|.  CFArray is used instead of NSArray because NSArray wants to
+  // retain each object you add to it, and you can't retain an
+  // NSAutoreleasePool.
+  mAutoreleasePools = ::CFArrayCreateMutable(nullptr, 0, nullptr);
+  NS_ENSURE_STATE(mAutoreleasePools);
+
+  bool isNSApplicationProcessType =
+      (XRE_GetProcessType() != GeckoProcessType_RDD) &&
+      (XRE_GetProcessType() != GeckoProcessType_Socket);
+
+  if (isNSApplicationProcessType) {
+    // This call initializes NSApplication unless:
+    // 1) we're using xre -- NSApp's already been initialized by
+    //    MacApplicationDelegate.mm's EnsureUseCocoaDockAPI().
+    // 2) an embedding app that uses NSApplicationMain() is running -- NSApp's
+    //    already been initialized and its main run loop is already running.
+    [[NSBundle mainBundle] loadNibNamed:@"res/MainMenu"
+                                  owner:[GeckoNSApplication sharedApplication]
+                        topLevelObjects:nil];
+  }
+
+  mDelegate = [[AppShellDelegate alloc] initWithAppShell:this];
+  NS_ENSURE_STATE(mDelegate);
+
+  // Add a CFRunLoopSource to the main native run loop.  The source is
+  // responsible for interrupting the run loop when Gecko events are ready.
+
+  mCFRunLoop = [[NSRunLoop currentRunLoop] getCFRunLoop];
+  NS_ENSURE_STATE(mCFRunLoop);
+  ::CFRetain(mCFRunLoop);
+
+  CFRunLoopSourceContext context;
+  bzero(&context, sizeof(context));
+  // context.version = 0;
+  context.info = this;
+  context.perform = ProcessGeckoEvents;
+
+  mCFRunLoopSource = ::CFRunLoopSourceCreate(kCFAllocatorDefault, 0, &context);
+  NS_ENSURE_STATE(mCFRunLoopSource);
+
+  ::CFRunLoopAddSource(mCFRunLoop, mCFRunLoopSource, kCFRunLoopCommonModes);
+
+  // Add a CFRunLoopObserver so that the profiler can be notified when we enter
+  // and exit the waiting state.
+  CFRunLoopObserverContext observerContext;
+  PodZero(&observerContext);
+  observerContext.info = this;
+
+  mCFRunLoopObserver = ::CFRunLoopObserverCreate(
+      kCFAllocatorDefault,
+      kCFRunLoopBeforeWaiting | kCFRunLoopAfterWaiting | kCFRunLoopExit, true,
+      0, RunLoopObserverCallback, &observerContext);
+  NS_ENSURE_STATE(mCFRunLoopObserver);
+
+  ::CFRunLoopAddObserver(mCFRunLoop, mCFRunLoopObserver, kCFRunLoopCommonModes);
+
+  hal::Init();
+
+  if (XRE_IsParentProcess()) {
+    ScreenManager& screenManager = ScreenManager::GetSingleton();
+
+    if (gfxPlatform::IsHeadless()) {
+      screenManager.SetHelper(mozilla::MakeUnique<HeadlessScreenHelper>());
+    } else {
+      screenManager.SetHelper(mozilla::MakeUnique<ScreenHelperCocoa>());
+    }
+
+    InitMemoryPressureObserver();
+  }
+
+  nsresult rv = nsBaseAppShell::Init();
+
+  if (isNSApplicationProcessType && !gAppShellMethodsSwizzled) {
+    // We should only replace the original terminate: method if we're not
+    // running in a Cocoa embedder. See bug 604901.
+    if (!mRunningCocoaEmbedded) {
+      nsToolkit::SwizzleMethods([NSApplication class], @selector(terminate:),
+                                @selector(nsAppShell_NSApplication_terminate:));
+    }
+    gAppShellMethodsSwizzled = true;
+  }
+
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
+  if (Preferences::GetBool("security.sandbox.mac.track.violations", false)) {
+    nsSandboxViolationSink::Start();
+  }
+#endif
+
+  [localPool release];
+
+  return rv;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+// ProcessGeckoEvents
+//
+// The "perform" target of mCFRunLoop, called when mCFRunLoopSource is
+// signalled from ScheduleNativeEventCallback.
+//
+// Arrange for Gecko events to be processed on demand (in response to a call
+// to ScheduleNativeEventCallback(), if processing of Gecko events via "native
+// methods" hasn't been suspended).  This happens in NativeEventCallback().
+//
+// protected static
+void nsAppShell::ProcessGeckoEvents(void* aInfo) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+  AUTO_PROFILER_LABEL("nsAppShell::ProcessGeckoEvents", OTHER);
+
+  nsAppShell* self = static_cast<nsAppShell*>(aInfo);
+
+  if (self->mRunningEventLoop) {
+    self->mRunningEventLoop = false;
+
+    // The run loop may be sleeping -- [NSRunLoop runMode:...]
+    // won't return until it's given a reason to wake up.  Awaken it by
+    // posting a bogus event.  There's no need to make the event
+    // presentable.
+    //
+    // But _don't_ set windowNumber to '-1' -- that can lead to nasty
+    // weirdness like bmo bug 397039 (a crash in [NSApp sendEvent:] on one of
+    // these fake events, because the -1 has gotten changed into the number
+    // of an actual NSWindow object, and that NSWindow object has just been
+    // destroyed).  Setting windowNumber to '0' seems to work fine -- this
+    // seems to prevent the OS from ever trying to associate our bogus event
+    // with a particular NSWindow object.
+    [NSApp postEvent:[NSEvent otherEventWithType:NSEventTypeApplicationDefined
+                                        location:NSMakePoint(0, 0)
+                                   modifierFlags:0
+                                       timestamp:0
+                                    windowNumber:0
+                                         context:NULL
+                                         subtype:kEventSubtypeNone
+                                           data1:0
+                                           data2:0]
+             atStart:NO];
+    // Previously we used to send this second event regardless of
+    // self->mRunningEventLoop. However, that was removed in bug 1690687 for
+    // performance reasons. It is still needed for the mRunningEventLoop case
+    // otherwise we'll get in a cycle of sending postEvent followed by the
+    // DummyEvent inserted by nsBaseAppShell::OnProcessNextEvent. This second
+    // event will cause the second call to AcquireFirstMatchingEventInQueue in
+    // nsAppShell::ProcessNextNativeEvent to return true. Which makes
+    // nsBaseAppShell::OnProcessNextEvent call
+    // nsAppShell::ProcessNextNativeEvent again during which it will loop until
+    // it sleeps because ProcessGeckoEvents() won't be called for the
+    // DummyEvent.
+    //
+    // This is not a good approach and we should fix things up so that only
+    // one postEvent is needed.
+    [NSApp postEvent:[NSEvent otherEventWithType:NSEventTypeApplicationDefined
+                                        location:NSMakePoint(0, 0)
+                                   modifierFlags:0
+                                       timestamp:0
+                                    windowNumber:0
+                                         context:NULL
+                                         subtype:kEventSubtypeNone
+                                           data1:0
+                                           data2:0]
+             atStart:NO];
+  }
+
+  if (self->mSuspendNativeCount <= 0) {
+    ++self->mNativeEventCallbackDepth;
+    self->NativeEventCallback();
+    --self->mNativeEventCallbackDepth;
+  } else {
+    self->mSkippedNativeCallback = true;
+  }
+
+  if (self->mTerminated) {
+    // Still needed to avoid crashes on quit in most Mochitests.
+    [NSApp postEvent:[NSEvent otherEventWithType:NSEventTypeApplicationDefined
+                                        location:NSMakePoint(0, 0)
+                                   modifierFlags:0
+                                       timestamp:0
+                                    windowNumber:0
+                                         context:NULL
+                                         subtype:kEventSubtypeNone
+                                           data1:0
+                                           data2:0]
+             atStart:NO];
+  }
+  // Normally every call to ScheduleNativeEventCallback() results in
+  // exactly one call to ProcessGeckoEvents().  So each Release() here
+  // normally balances exactly one AddRef() in ScheduleNativeEventCallback().
+  // But if Exit() is called just after ScheduleNativeEventCallback(), the
+  // corresponding call to ProcessGeckoEvents() will never happen.  We check
+  // for this possibility in two different places -- here and in Exit()
+  // itself.  If we find here that Exit() has been called (that mTerminated
+  // is true), it's because we've been called recursively, that Exit() was
+  // called from self->NativeEventCallback() above, and that we're unwinding
+  // the recursion.  In this case we'll never be called again, and we balance
+  // here any extra calls to ScheduleNativeEventCallback().
+  //
+  // When ProcessGeckoEvents() is called recursively, it's because of a
+  // call to ScheduleNativeEventCallback() from NativeEventCallback().  We
+  // balance the "extra" AddRefs here (rather than always in Exit()) in order
+  // to ensure that 'self' stays alive until the end of this method.  We also
+  // make sure not to finish the balancing until all the recursion has been
+  // unwound.
+  if (self->mTerminated) {
+    int32_t releaseCount = 0;
+    if (self->mNativeEventScheduledDepth > self->mNativeEventCallbackDepth) {
+      releaseCount = PR_ATOMIC_SET(&self->mNativeEventScheduledDepth,
+                                   self->mNativeEventCallbackDepth);
+    }
+    while (releaseCount-- > self->mNativeEventCallbackDepth) self->Release();
+  } else {
+    // As best we can tell, every call to ProcessGeckoEvents() is triggered
+    // by a call to ScheduleNativeEventCallback().  But we've seen a few
+    // (non-reproducible) cases of double-frees that *might* have been caused
+    // by spontaneous calls (from the OS) to ProcessGeckoEvents().  So we
+    // deal with that possibility here.
+    if (PR_ATOMIC_DECREMENT(&self->mNativeEventScheduledDepth) < 0) {
+      PR_ATOMIC_SET(&self->mNativeEventScheduledDepth, 0);
+      NS_WARNING("Spontaneous call to ProcessGeckoEvents()!");
+    } else {
+      self->Release();
+    }
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// WillTerminate
+//
+// Called by the AppShellDelegate when an NSApplicationWillTerminate
+// notification is posted.  After this method is called, native events should
+// no longer be processed.  The NSApplicationWillTerminate notification is
+// only posted when [NSApp terminate:] is called, which doesn't happen on a
+// "normal" application quit.
+//
+// public
+void nsAppShell::WillTerminate() {
+  if (mTerminated) return;
+
+  // Make sure that the nsAppExitEvent posted by nsAppStartup::Quit() (called
+  // from [MacApplicationDelegate applicationShouldTerminate:]) gets run.
+  NS_ProcessPendingEvents(NS_GetCurrentThread());
+
+  mTerminated = true;
+}
+
+// ScheduleNativeEventCallback
+//
+// Called (possibly on a non-main thread) when Gecko has an event that
+// needs to be processed.  The Gecko event needs to be processed on the
+// main thread, so the native run loop must be interrupted.
+//
+// In nsBaseAppShell.cpp, the mNativeEventPending variable is used to
+// ensure that ScheduleNativeEventCallback() is called no more than once
+// per call to NativeEventCallback().  ProcessGeckoEvents() can skip its
+// call to NativeEventCallback() if processing of Gecko events by native
+// means is suspended (using nsIAppShell::SuspendNative()), which will
+// suspend calls from nsBaseAppShell::OnDispatchedEvent() to
+// ScheduleNativeEventCallback().  But when Gecko event processing by
+// native means is resumed (in ResumeNative()), an extra call is made to
+// ScheduleNativeEventCallback() (from ResumeNative()).  This triggers
+// another call to ProcessGeckoEvents(), which calls NativeEventCallback(),
+// and nsBaseAppShell::OnDispatchedEvent() resumes calling
+// ScheduleNativeEventCallback().
+//
+// protected virtual
+void nsAppShell::ScheduleNativeEventCallback() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mTerminated) return;
+
+  // Each AddRef() here is normally balanced by exactly one Release() in
+  // ProcessGeckoEvents().  But there are exceptions, for which see
+  // ProcessGeckoEvents() and Exit().
+  NS_ADDREF_THIS();
+  PR_ATOMIC_INCREMENT(&mNativeEventScheduledDepth);
+
+  // This will invoke ProcessGeckoEvents on the main thread.
+  ::CFRunLoopSourceSignal(mCFRunLoopSource);
+  ::CFRunLoopWakeUp(mCFRunLoop);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Undocumented Cocoa Event Manager function, present in the same form since
+// at least OS X 10.6.
+extern "C" EventAttributes GetEventAttributes(EventRef inEvent);
+
+// ProcessNextNativeEvent
+//
+// If aMayWait is false, process a single native event.  If it is true, run
+// the native run loop until stopped by ProcessGeckoEvents.
+//
+// Returns true if more events are waiting in the native event queue.
+//
+// protected virtual
+bool nsAppShell::ProcessNextNativeEvent(bool aMayWait) {
+  bool moreEvents = false;
+
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  bool eventProcessed = false;
+  NSString* currentMode = nil;
+
+  if (mTerminated) return false;
+
+  // Do not call -[NSApplication nextEventMatchingMask:...] when we're trying to
+  // close a native menu. Doing so could confuse the NSMenu's closing mechanism.
+  // Instead, we try to unwind the stack as quickly as possible and return to
+  // the parent event loop. At that point, native events will be processed.
+  if (MOZMenuOpeningCoordinator.needToUnwindForMenuClosing) {
+    return false;
+  }
+
+  bool wasRunningEventLoop = mRunningEventLoop;
+  mRunningEventLoop = aMayWait;
+  NSDate* waitUntil = nil;
+  if (aMayWait) waitUntil = [NSDate distantFuture];
+
+  NSRunLoop* currentRunLoop = [NSRunLoop currentRunLoop];
+
+  EventQueueRef currentEventQueue = GetCurrentEventQueue();
+
+  if (aMayWait) {
+    mozilla::BackgroundHangMonitor().NotifyWait();
+  }
+
+  // Only call -[NSApp sendEvent:] (and indirectly send user-input events to
+  // Gecko) if aMayWait is true.  Tbis ensures most calls to -[NSApp
+  // sendEvent:] happen under nsAppShell::Run(), at the lowest level of
+  // recursion -- thereby making it less likely Gecko will process user-input
+  // events in the wrong order or skip some of them.  It also avoids eating
+  // too much CPU in nsBaseAppShell::OnProcessNextEvent() (which calls
+  // us) -- thereby avoiding the starvation of nsIRunnable events in
+  // nsThread::ProcessNextEvent().  For more information see bug 996848.
+  do {
+    // No autorelease pool is provided here, because OnProcessNextEvent
+    // and AfterProcessNextEvent are responsible for maintaining it.
+    NS_ASSERTION(mAutoreleasePools && ::CFArrayGetCount(mAutoreleasePools),
+                 "No autorelease pool for native event");
+
+    if (aMayWait && [[GeckoNSApplication sharedApplication] didLaunch]) {
+      currentMode = [currentRunLoop currentMode];
+      if (!currentMode) currentMode = NSDefaultRunLoopMode;
+      NSEvent* nextEvent = [NSApp nextEventMatchingMask:NSEventMaskAny
+                                              untilDate:waitUntil
+                                                 inMode:currentMode
+                                                dequeue:YES];
+      if (nextEvent) {
+        mozilla::BackgroundHangMonitor().NotifyActivity();
+        [NSApp sendEvent:nextEvent];
+        eventProcessed = true;
+      }
+    } else {
+      // In at least 10.15, AcquireFirstMatchingEventInQueue will move 1
+      // CGEvent from the CGEvent queue into the Carbon event queue.
+      // Unfortunately, once an event has been moved to the Carbon event queue
+      // it's no longer a candidate for coalescing. This means that even if we
+      // don't remove the event from the queue, just calling
+      // AcquireFirstMatchingEventInQueue can cause behaviour change. Prior to
+      // bug 1690687 landing, the event that we got from
+      // AcquireFirstMatchingEventInQueue was often our own ApplicationDefined
+      // event. However, once we stopped posting that event on every Gecko
+      // event we're much more likely to get a CGEvent. When we have a high
+      // amount of load on the main thread, we end up alternating between Gecko
+      // events and native events.  Without CGEvent coalescing, the native
+      // event events can accumulate in the Carbon event queue which will
+      // manifest as laggy scrolling.
+#if 1
+      eventProcessed = false;
+      break;
+#else
+      // AcquireFirstMatchingEventInQueue() doesn't spin the (native) event
+      // loop, though it does queue up any newly available events from the
+      // window server.
+      EventRef currentEvent = AcquireFirstMatchingEventInQueue(
+          currentEventQueue, 0, NULL, kEventQueueOptionsNone);
+      if (!currentEvent) {
+        continue;
+      }
+      EventAttributes attrs = GetEventAttributes(currentEvent);
+      UInt32 eventKind = GetEventKind(currentEvent);
+      UInt32 eventClass = GetEventClass(currentEvent);
+      bool osCocoaEvent =
+          ((eventClass == 'appl') || (eventClass == kEventClassAppleEvent) ||
+           ((eventClass == 'cgs ') &&
+            (eventKind != NSEventTypeApplicationDefined)));
+      // If attrs is kEventAttributeUserEvent or kEventAttributeMonitored
+      // (i.e. a user input event), we shouldn't process it here while
+      // aMayWait is false.  Likewise if currentEvent will eventually be
+      // turned into an OS-defined Cocoa event, or otherwise needs AppKit
+      // processing.  Doing otherwise risks doing too much work here, and
+      // preventing the event from being properly processed by the AppKit
+      // framework.
+      if ((attrs != kEventAttributeNone) || osCocoaEvent) {
+        // Since we can't process the next event here (while aMayWait is false),
+        // we want moreEvents to be false on return.
+        eventProcessed = false;
+        // This call to ReleaseEvent() matches a call to RetainEvent() in
+        // AcquireFirstMatchingEventInQueue() above.
+        ReleaseEvent(currentEvent);
+        break;
+      }
+      // This call to RetainEvent() matches a call to ReleaseEvent() in
+      // RemoveEventFromQueue() below.
+      RetainEvent(currentEvent);
+      RemoveEventFromQueue(currentEventQueue, currentEvent);
+      EventTargetRef eventDispatcherTarget = GetEventDispatcherTarget();
+      SendEventToEventTarget(currentEvent, eventDispatcherTarget);
+      // This call to ReleaseEvent() matches a call to RetainEvent() in
+      // AcquireFirstMatchingEventInQueue() above.
+      ReleaseEvent(currentEvent);
+      eventProcessed = true;
+#endif
+    }
+  } while (mRunningEventLoop);
+
+  if (eventProcessed) {
+    moreEvents =
+        (AcquireFirstMatchingEventInQueue(currentEventQueue, 0, NULL,
+                                          kEventQueueOptionsNone) != NULL);
+  }
+
+  mRunningEventLoop = wasRunningEventLoop;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+
+  if (!moreEvents) {
+    nsChildView::UpdateCurrentInputEventCount();
+  }
+
+  return moreEvents;
+}
+
+// Attempt to work around bug 1801419 by loading and initializing the
+// SidecarCore private framework as the app shell starts up. This normally
+// happens on demand, the first time any Cmd-key combination is pressed, and
+// sometimes triggers crashes, caused by an Apple bug. We hope that doing it
+// now, and somewhat more simply, will avoid the crashes. They happen
+// (intermittently) when SidecarCore code tries to access C strings in special
+// sections of its own __TEXT segment, and triggers fatal page faults (which
+// is Apple's bug). Many of the C strings are part of the Objective-C class
+// hierarchy (class names and so forth). We hope that adding them to this
+// hierarchy will "pin" them in place -- so they'll rarely, if ever, be paged
+// out again. Bug 1801419's crashes happen much more often on macOS 13
+// (Ventura) than on other versions of macOS. So we only use this hack on
+// macOS 13 and up.
+static void PinSidecarCoreTextCStringSections() {
+  if (!dlopen(
+          "/System/Library/PrivateFrameworks/SidecarCore.framework/SidecarCore",
+          RTLD_LAZY)) {
+    return;
+  }
+
+  // Explicitly run the most basic part of the initialization code that
+  // normally runs automatically on the first Cmd-key combination.
+  Class displayManagerClass = NSClassFromString(@"SidecarDisplayManager");
+  if ([displayManagerClass respondsToSelector:@selector(sharedManager)]) {
+    id sharedManager =
+        [displayManagerClass performSelector:@selector(sharedManager)];
+    if ([sharedManager respondsToSelector:@selector(devices)]) {
+      [sharedManager performSelector:@selector(devices)];
+    }
+  }
+}
+
+// Run
+//
+// Overrides the base class's Run() method to call [NSApp run] (which spins
+// the native run loop until the application quits).  Since (unlike the base
+// class's Run() method) we don't process any Gecko events here, they need
+// to be processed elsewhere (in NativeEventCallback(), called from
+// ProcessGeckoEvents()).
+//
+// Camino called [NSApp run] on its own (via NSApplicationMain()), and so
+// didn't call nsAppShell::Run().
+//
+// public
+NS_IMETHODIMP
+nsAppShell::Run(void) {
+  NS_ASSERTION(!mStarted, "nsAppShell::Run() called multiple times");
+  if (mStarted || mTerminated) return NS_OK;
+
+  mStarted = true;
+
+  if (XRE_IsParentProcess()) {
+    if (nsCocoaFeatures::OnVenturaOrLater()) {
+      PinSidecarCoreTextCStringSections();
+    }
+    AddScreenWakeLockListener();
+  }
+
+  // We use the native Gecko event loop in content processes.
+  nsresult rv = NS_OK;
+  if (XRE_UseNativeEventProcessing()) {
+    NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+    [NSApp run];
+    NS_OBJC_END_TRY_IGNORE_BLOCK;
+  } else {
+    rv = nsBaseAppShell::Run();
+  }
+
+  if (XRE_IsParentProcess()) {
+    RemoveScreenWakeLockListener();
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsAppShell::Exit(void) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // This method is currently called more than once -- from (according to
+  // mento) an nsAppExitEvent dispatched by nsAppStartup::Quit() and from an
+  // XPCOM shutdown notification that nsBaseAppShell has registered to
+  // receive.  So we need to ensure that multiple calls won't break anything.
+  if (mTerminated) {
+    return NS_OK;
+  }
+
+  mTerminated = true;
+
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
+  nsSandboxViolationSink::Stop();
+#endif
+
+  // Quoting from Apple's doc on the [NSApplication stop:] method (from their
+  // doc on the NSApplication class):  "If this method is invoked during a
+  // modal event loop, it will break that loop but not the main event loop."
+  // nsAppShell::Exit() shouldn't be called from a modal event loop.  So if
+  // it is we complain about it (to users of debug builds) and call [NSApp
+  // stop:] one extra time.  (I'm not sure if modal event loops can be nested
+  // -- Apple's docs don't say one way or the other.  But the return value
+  // of [NSApp _isRunningModal] doesn't change immediately after a call to
+  // [NSApp stop:], so we have to assume that one extra call to [NSApp stop:]
+  // will do the job.)
+  BOOL cocoaModal = [NSApp _isRunningModal];
+  NS_ASSERTION(!cocoaModal,
+               "Don't call nsAppShell::Exit() from a modal event loop!");
+  if (cocoaModal) [NSApp stop:nullptr];
+  [NSApp stop:nullptr];
+
+  // A call to Exit() just after a call to ScheduleNativeEventCallback()
+  // prevents the (normally) matching call to ProcessGeckoEvents() from
+  // happening.  If we've been called from ProcessGeckoEvents() (as usually
+  // happens), we take care of it there.  But if we have an unbalanced call
+  // to ScheduleNativeEventCallback() and ProcessGeckoEvents() isn't on the
+  // stack, we need to take care of the problem here.
+  if (!mNativeEventCallbackDepth && mNativeEventScheduledDepth) {
+    int32_t releaseCount = PR_ATOMIC_SET(&mNativeEventScheduledDepth, 0);
+    while (releaseCount-- > 0) NS_RELEASE_THIS();
+  }
+
+  return nsBaseAppShell::Exit();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+// OnProcessNextEvent
+//
+// This nsIThreadObserver method is called prior to processing an event.
+// Set up an autorelease pool that will service any autoreleased Cocoa
+// objects during this event.  This includes native events processed by
+// ProcessNextNativeEvent.  The autorelease pool will be popped by
+// AfterProcessNextEvent, it is important for these two methods to be
+// tightly coupled.
+//
+// public
+NS_IMETHODIMP
+nsAppShell::OnProcessNextEvent(nsIThreadInternal* aThread, bool aMayWait) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NS_ASSERTION(mAutoreleasePools,
+               "No stack on which to store autorelease pool");
+
+  NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
+  ::CFArrayAppendValue(mAutoreleasePools, pool);
+
+  return nsBaseAppShell::OnProcessNextEvent(aThread, aMayWait);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+// AfterProcessNextEvent
+//
+// This nsIThreadObserver method is called after event processing is complete.
+// The Cocoa implementation cleans up the autorelease pool create by the
+// previous OnProcessNextEvent call.
+//
+// public
+NS_IMETHODIMP
+nsAppShell::AfterProcessNextEvent(nsIThreadInternal* aThread,
+                                  bool aEventWasProcessed) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  CFIndex count = ::CFArrayGetCount(mAutoreleasePools);
+
+  NS_ASSERTION(mAutoreleasePools && count,
+               "Processed an event, but there's no autorelease pool?");
+
+  const NSAutoreleasePool* pool = static_cast<const NSAutoreleasePool*>(
+      ::CFArrayGetValueAtIndex(mAutoreleasePools, count - 1));
+  ::CFArrayRemoveValueAtIndex(mAutoreleasePools, count - 1);
+  [pool release];
+
+  return nsBaseAppShell::AfterProcessNextEvent(aThread, aEventWasProcessed);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void nsAppShell::InitMemoryPressureObserver() {
+  // Testing shows that sometimes the memory pressure event is not fired for
+  // over a minute after the memory pressure change is reflected in sysctl
+  // values. Hence this may need to be augmented with polling of the memory
+  // pressure sysctls for lower latency reactions to OS memory pressure. This
+  // was also observed when using DISPATCH_QUEUE_PRIORITY_HIGH.
+  mMemoryPressureSource = dispatch_source_create(
+      DISPATCH_SOURCE_TYPE_MEMORYPRESSURE, 0,
+      DISPATCH_MEMORYPRESSURE_NORMAL | DISPATCH_MEMORYPRESSURE_WARN |
+          DISPATCH_MEMORYPRESSURE_CRITICAL,
+      dispatch_get_main_queue());
+
+  dispatch_source_set_event_handler(mMemoryPressureSource, ^{
+    dispatch_source_memorypressure_flags_t pressureLevel =
+        dispatch_source_get_data(mMemoryPressureSource);
+    nsAppShell::OnMemoryPressureChanged(pressureLevel);
+  });
+
+  dispatch_resume(mMemoryPressureSource);
+
+  // Initialize the memory watcher.
+  RefPtr<mozilla::nsAvailableMemoryWatcherBase> watcher(
+      nsAvailableMemoryWatcherBase::GetSingleton());
+}
+
+void nsAppShell::OnMemoryPressureChanged(
+    dispatch_source_memorypressure_flags_t aPressureLevel) {
+  // The memory pressure dispatch source is created (above) with
+  // dispatch_get_main_queue() which always fires on the main thread.
+  MOZ_ASSERT(NS_IsMainThread());
+
+  MacMemoryPressureLevel geckoPressureLevel;
+  switch (aPressureLevel) {
+    case DISPATCH_MEMORYPRESSURE_NORMAL:
+      geckoPressureLevel = MacMemoryPressureLevel::Value::eNormal;
+      break;
+    case DISPATCH_MEMORYPRESSURE_WARN:
+      geckoPressureLevel = MacMemoryPressureLevel::Value::eWarning;
+      break;
+    case DISPATCH_MEMORYPRESSURE_CRITICAL:
+      geckoPressureLevel = MacMemoryPressureLevel::Value::eCritical;
+      break;
+    default:
+      geckoPressureLevel = MacMemoryPressureLevel::Value::eUnexpected;
+  }
+
+  RefPtr<mozilla::nsAvailableMemoryWatcherBase> watcher(
+      nsAvailableMemoryWatcherBase::GetSingleton());
+  watcher->OnMemoryPressureChanged(geckoPressureLevel);
+}
+
+// AppShellDelegate implementation
+
+@implementation AppShellDelegate
+// initWithAppShell:
+//
+// Constructs the AppShellDelegate object
+- (id)initWithAppShell:(nsAppShell*)aAppShell {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if ((self = [self init])) {
+    mAppShell = aAppShell;
+
+    [[NSNotificationCenter defaultCenter]
+        addObserver:self
+           selector:@selector(applicationWillTerminate:)
+               name:NSApplicationWillTerminateNotification
+             object:NSApp];
+    [[NSNotificationCenter defaultCenter]
+        addObserver:self
+           selector:@selector(applicationDidBecomeActive:)
+               name:NSApplicationDidBecomeActiveNotification
+             object:NSApp];
+    [[NSNotificationCenter defaultCenter]
+        addObserver:self
+           selector:@selector(timezoneChanged:)
+               name:NSSystemTimeZoneDidChangeNotification
+             object:nil];
+  }
+
+  return self;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (void)dealloc {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+  [[NSDistributedNotificationCenter defaultCenter] removeObserver:self];
+  [super dealloc];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// applicationWillTerminate:
+//
+// Notify the nsAppShell that native event processing should be discontinued.
+- (void)applicationWillTerminate:(NSNotification*)aNotification {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  mAppShell->WillTerminate();
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// applicationDidBecomeActive
+//
+// Make sure TextInputHandler::sLastModifierState is updated when we become
+// active (since we won't have received [ChildView flagsChanged:] messages
+// while inactive).
+- (void)applicationDidBecomeActive:(NSNotification*)aNotification {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // [NSEvent modifierFlags] is valid on every kind of event, so we don't need
+  // to worry about getting an NSInternalInconsistencyException here.
+  NSEvent* currentEvent = [NSApp currentEvent];
+  if (currentEvent) {
+    TextInputHandler::sLastModifierState =
+        [currentEvent modifierFlags] &
+        NSEventModifierFlagDeviceIndependentFlagsMask;
+  }
+
+  nsCOMPtr<nsIObserverService> observerService = services::GetObserverService();
+  if (observerService) {
+    observerService->NotifyObservers(
+        nullptr, NS_WIDGET_MAC_APP_ACTIVATE_OBSERVER_TOPIC, nullptr);
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)timezoneChanged:(NSNotification*)aNotification {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  nsBaseAppShell::OnSystemTimezoneChange();
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+@end
+
+// We hook terminate: in order to make OS-initiated termination work nicely
+// with Gecko's shutdown sequence.  (Two ways to trigger OS-initiated
+// termination:  1) Quit from the Dock menu; 2) Log out from (or shut down)
+// your computer while the browser is active.)
+@interface NSApplication (MethodSwizzling)
+- (void)nsAppShell_NSApplication_terminate:(id)sender;
+@end
+
+@implementation NSApplication (MethodSwizzling)
+
+// Called by the OS after [MacApplicationDelegate applicationShouldTerminate:]
+// has returned NSTerminateNow.  This method "subclasses" and replaces the
+// OS's original implementation.  The only thing the orginal method does which
+// we need is that it posts NSApplicationWillTerminateNotification.  Everything
+// else is unneeded (because it's handled elsewhere), or actively interferes
+// with Gecko's shutdown sequence.  For example the original terminate: method
+// causes the app to exit() inside [NSApp run] (called from nsAppShell::Run()
+// above), which means that nothing runs after the call to nsAppStartup::Run()
+// in XRE_Main(), which in particular means that ScopedXPCOMStartup's destructor
+// and NS_ShutdownXPCOM() never get called.
+- (void)nsAppShell_NSApplication_terminate:(id)sender {
+  [[NSNotificationCenter defaultCenter]
+      postNotificationName:NSApplicationWillTerminateNotification
+                    object:NSApp];
+}
+
+@end
diff --git a/widget/cocoa/nsBidiKeyboard.h b/widget/cocoa/nsBidiKeyboard.h
new file mode 100644
index 0000000000..3a9a6fe2fb
--- /dev/null
+++ b/widget/cocoa/nsBidiKeyboard.h
@@ -0,0 +1,23 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsBidiKeyboard_h_
+#define nsBidiKeyboard_h_
+
+#include "nsIBidiKeyboard.h"
+
+class nsBidiKeyboard : public nsIBidiKeyboard {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIBIDIKEYBOARD
+
+  nsBidiKeyboard();
+
+ protected:
+  virtual ~nsBidiKeyboard();
+};
+
+#endif  // nsBidiKeyboard_h_
diff --git a/widget/cocoa/nsBidiKeyboard.mm b/widget/cocoa/nsBidiKeyboard.mm
new file mode 100644
index 0000000000..4193bdf6f0
--- /dev/null
+++ b/widget/cocoa/nsBidiKeyboard.mm
@@ -0,0 +1,38 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsBidiKeyboard.h"
+#include "nsCocoaUtils.h"
+#include "TextInputHandler.h"
+#include "nsIWidget.h"
+
+// This must be the last include:
+#include "nsObjCExceptions.h"
+
+using namespace mozilla::widget;
+
+NS_IMPL_ISUPPORTS(nsBidiKeyboard, nsIBidiKeyboard)
+
+nsBidiKeyboard::nsBidiKeyboard() : nsIBidiKeyboard() { Reset(); }
+
+nsBidiKeyboard::~nsBidiKeyboard() {}
+
+NS_IMETHODIMP nsBidiKeyboard::Reset() { return NS_OK; }
+
+NS_IMETHODIMP nsBidiKeyboard::IsLangRTL(bool* aIsRTL) {
+  *aIsRTL = TISInputSourceWrapper::CurrentInputSource().IsForRTLLanguage();
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBidiKeyboard::GetHaveBidiKeyboards(bool* aResult) {
+  // not implemented yet
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+// static
+already_AddRefed<nsIBidiKeyboard> nsIWidget::CreateBidiKeyboardInner() {
+  return do_AddRef(new nsBidiKeyboard());
+}
diff --git a/widget/cocoa/nsChangeObserver.h b/widget/cocoa/nsChangeObserver.h
new file mode 100644
index 0000000000..aacf837bb5
--- /dev/null
+++ b/widget/cocoa/nsChangeObserver.h
@@ -0,0 +1,71 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsChangeObserver_h_
+#define nsChangeObserver_h_
+
+class nsIContent;
+class nsAtom;
+namespace mozilla {
+namespace dom {
+class Document;
+}
+}  // namespace mozilla
+
+#define NS_DECL_CHANGEOBSERVER                                            \
+  void ObserveAttributeChanged(mozilla::dom::Document* aDocument,         \
+                               nsIContent* aContent, nsAtom* aAttribute)  \
+      override;                                                           \
+  void ObserveContentRemoved(mozilla::dom::Document* aDocument,           \
+                             nsIContent* aContainer, nsIContent* aChild,  \
+                             nsIContent* aPreviousChild) override;        \
+  void ObserveContentInserted(mozilla::dom::Document* aDocument,          \
+                              nsIContent* aContainer, nsIContent* aChild) \
+      override;
+
+// Something that wants to be alerted to changes in attributes or changes in
+// its corresponding content object.
+//
+// This interface is used by our menu code so we only have to have one
+// nsIMutationObserver per menu subtree root (e.g. per menubar).
+//
+// Any class that implements this interface must take care to unregister itself
+// on deletion.
+//
+// XXXmstange The methods below use nsIContent*. Eventually, the should be
+// converted to use mozilla::dom::Element* instead.
+class nsChangeObserver {
+ public:
+  // Called when the attribute aAttribute on the element aContent has changed.
+  // Only if aContent is being observed by this nsChangeObserver.
+  virtual void ObserveAttributeChanged(mozilla::dom::Document* aDocument,
+                                       nsIContent* aContent,
+                                       nsAtom* aAttribute) = 0;
+
+  // Called when aChild has been removed from its parent aContainer.
+  // aPreviousSibling is the old previous sibling of aChild.
+  // aContainer is always the old parent node of aChild and of aPreviousSibling.
+  // Only called if aContainer or aContainer's parent node are being observed
+  // by this nsChangeObserver.
+  // In other words: If you observe an element, ObserveContentRemoved is called
+  // if that element's children and grandchildren are removed. NOT if the
+  // observed element itself is removed.
+  virtual void ObserveContentRemoved(mozilla::dom::Document* aDocument,
+                                     nsIContent* aContainer, nsIContent* aChild,
+                                     nsIContent* aPreviousSibling) = 0;
+
+  // Called when aChild has been inserted into its new parent aContainer.
+  // Only called if aContainer or aContainer's parent node are being observed
+  // by this nsChangeObserver.
+  // In other words: If you observe an element, ObserveContentInserted is called
+  // if that element receives a new child or grandchild. NOT if the observed
+  // element itself is inserted anywhere.
+  virtual void ObserveContentInserted(mozilla::dom::Document* aDocument,
+                                      nsIContent* aContainer,
+                                      nsIContent* aChild) = 0;
+};
+
+#endif  // nsChangeObserver_h_
diff --git a/widget/cocoa/nsChildView.h b/widget/cocoa/nsChildView.h
new file mode 100644
index 0000000000..3dfc3af9d8
--- /dev/null
+++ b/widget/cocoa/nsChildView.h
@@ -0,0 +1,621 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsChildView_h_
+#define nsChildView_h_
+
+// formal protocols
+#include "mozView.h"
+#ifdef ACCESSIBILITY
+#  include "mozilla/a11y/LocalAccessible.h"
+#  include "mozAccessibleProtocol.h"
+#endif
+
+#include "nsISupports.h"
+#include "nsBaseWidget.h"
+#include "nsIWeakReferenceUtils.h"
+#include "TextInputHandler.h"
+#include "nsCocoaUtils.h"
+#include "gfxQuartzSurface.h"
+#include "GLContextTypes.h"
+#include "mozilla/DataMutex.h"
+#include "mozilla/Mutex.h"
+#include "nsRegion.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/webrender/WebRenderTypes.h"
+
+#include "nsString.h"
+#include "nsIDragService.h"
+#include "ViewRegion.h"
+#include "CFTypeRefPtr.h"
+
+#import <Carbon/Carbon.h>
+#import <Cocoa/Cocoa.h>
+#import <AppKit/NSOpenGL.h>
+
+class nsChildView;
+class nsCocoaWindow;
+
+namespace {
+class GLPresenter;
+}  // namespace
+
+namespace mozilla {
+enum class NativeKeyBindingsType : uint8_t;
+
+class InputData;
+class PanGestureInput;
+class VibrancyManager;
+namespace layers {
+class GLManager;
+class IAPZCTreeManager;
+class NativeLayerRootCA;
+class NativeLayerCA;
+}  // namespace layers
+namespace widget {
+class WidgetRenderingContext;
+}  // namespace widget
+}  // namespace mozilla
+
+@class PixelHostingView;
+
+@interface NSEvent (Undocumented)
+
+// Return Cocoa event's corresponding Carbon event.  Not initialized (on
+// synthetic events) until the OS actually "sends" the event.  This method
+// has been present in the same form since at least OS X 10.2.8.
+- (EventRef)_eventRef;
+
+// stage From 10.10.3 for force touch event
+@property(readonly) NSInteger stage;
+
+@end
+
+@interface NSView (Undocumented)
+
+// Undocumented method of one or more of NSFrameView's subclasses.  Called
+// when one or more of the titlebar buttons needs to be repositioned, to
+// disappear, or to reappear (say if the window's style changes).  If
+// 'redisplay' is true, the entire titlebar (the window's top 22 pixels) is
+// marked as needing redisplay.  This method has been present in the same
+// format since at least OS X 10.5.
+- (void)_tileTitlebarAndRedisplay:(BOOL)redisplay;
+
+// The following undocumented methods are used to work around bug 1069658,
+// which is an Apple bug or design flaw that effects Yosemite.  None of them
+// were present prior to Yosemite (OS X 10.10).
+- (NSView*)titlebarView;           // Method of NSThemeFrame
+- (NSView*)titlebarContainerView;  // Method of NSThemeFrame
+- (BOOL)transparent;  // Method of NSTitlebarView and NSTitlebarContainerView
+- (void)setTransparent:(BOOL)transparent;  // Method of NSTitlebarView and
+                                           // NSTitlebarContainerView
+
+// Available since 10.7.4:
+- (void)viewDidChangeBackingProperties;
+@end
+
+@interface ChildView : NSView <
+#ifdef ACCESSIBILITY
+                           mozAccessible,
+#endif
+                           mozView,
+                           NSTextInputClient,
+                           NSDraggingSource,
+                           NSDraggingDestination,
+                           NSPasteboardItemDataProvider> {
+ @private
+  // the nsChildView that created the view. It retains this NSView, so
+  // the link back to it must be weak.
+  nsChildView* mGeckoChild;
+
+  // Text input handler for mGeckoChild and us.  Note that this is a weak
+  // reference.  Ideally, this should be a strong reference but a ChildView
+  // object can live longer than the mGeckoChild that owns it.  And if
+  // mTextInputHandler were a strong reference, this would make it difficult
+  // for Gecko's leak detector to detect leaked TextInputHandler objects.
+  // This is initialized by [mozView installTextInputHandler:aHandler] and
+  // cleared by [mozView uninstallTextInputHandler].
+  mozilla::widget::TextInputHandler* mTextInputHandler;  // [WEAK]
+
+  // when mouseDown: is called, we store its event here (strong)
+  NSEvent* mLastMouseDownEvent;
+
+  // Needed for IME support in e10s mode.  Strong.
+  NSEvent* mLastKeyDownEvent;
+
+  // Whether the last mouse down event was blocked from Gecko.
+  BOOL mBlockedLastMouseDown;
+
+  // when acceptsFirstMouse: is called, we store the event here (strong)
+  NSEvent* mClickThroughMouseDownEvent;
+
+  // WheelStart/Stop events should always come in pairs. This BOOL records the
+  // last received event so that, when we receive one of the events, we make
+  // sure to send its pair event first, in case we didn't yet for any reason.
+  BOOL mExpectingWheelStop;
+
+  // Whether we're inside updateRootCALayer at the moment.
+  BOOL mIsUpdatingLayer;
+
+  // Whether the drag and drop was performed.
+  BOOL mPerformedDrag;
+
+  // Holds our drag service across multiple drag calls. The reference to the
+  // service is obtained when the mouse enters the view and is released when
+  // the mouse exits or there is a drop. This prevents us from having to
+  // re-establish the connection to the service manager many times per second
+  // when handling |draggingUpdated:| messages.
+  nsIDragService* mDragService;
+
+  // Gestures support
+  //
+  // mGestureState is used to detect when Cocoa has called both
+  // magnifyWithEvent and rotateWithEvent within the same
+  // beginGestureWithEvent and endGestureWithEvent sequence. We
+  // discard the spurious gesture event so as not to confuse Gecko.
+  //
+  // mCumulativeRotation keeps track of the total amount of rotation
+  // performed during a rotate gesture so we can send that value with
+  // the final MozRotateGesture event.
+  enum {
+    eGestureState_None,
+    eGestureState_StartGesture,
+    eGestureState_MagnifyGesture,
+    eGestureState_RotateGesture
+  } mGestureState;
+  float mCumulativeRotation;
+
+#ifdef __LP64__
+  // Support for fluid swipe tracking.
+  BOOL* mCancelSwipeAnimation;
+#endif
+
+  // Whether this uses off-main-thread compositing.
+  BOOL mUsingOMTCompositor;
+
+  // Subviews of self, which act as container views for vibrancy views and
+  // non-draggable views.
+  NSView* mVibrancyViewsContainer;      // [STRONG]
+  NSView* mNonDraggableViewsContainer;  // [STRONG]
+
+  // The layer-backed view that hosts our drawing. Always non-null.
+  // This is a subview of self so that it can be ordered on top of
+  // mVibrancyViewsContainer.
+  PixelHostingView* mPixelHostingView;
+
+  // The CALayer that wraps Gecko's rendered contents. It's a sublayer of
+  // mPixelHostingView's backing layer. Always non-null.
+  CALayer* mRootCALayer;  // [STRONG]
+
+  // Last pressure stage by trackpad's force click
+  NSInteger mLastPressureStage;
+}
+
+// class initialization
++ (void)initialize;
+
++ (void)registerViewForDraggedTypes:(NSView*)aView;
+
+// these are sent to the first responder when the window key status changes
+- (void)viewsWindowDidBecomeKey;
+- (void)viewsWindowDidResignKey;
+
+// Stop NSView hierarchy being changed during [ChildView drawRect:]
+- (void)delayedTearDown;
+
+- (void)handleMouseMoved:(NSEvent*)aEvent;
+
+- (void)sendMouseEnterOrExitEvent:(NSEvent*)aEvent
+                            enter:(BOOL)aEnter
+                         exitFrom:
+                             (mozilla::WidgetMouseEvent::ExitFrom)aExitFrom;
+
+// Call this during operations that will likely trigger a main thread
+// CoreAnimation paint of the window, during which Gecko should do its own
+// painting and present the results atomically with that main thread
+// transaction. This method will suspend off-thread window updates so that the
+// upcoming paint can be atomic, and mark the layer as needing display so that
+// HandleMainThreadCATransaction gets called and Gecko gets a chance to paint.
+- (void)ensureNextCompositeIsAtomicWithMainThreadPaint;
+
+- (NSView*)vibrancyViewsContainer;
+- (NSView*)nonDraggableViewsContainer;
+- (NSView*)pixelHostingView;
+
+- (BOOL)isCoveringTitlebar;
+
+- (void)viewWillStartLiveResize;
+- (void)viewDidEndLiveResize;
+
+/*
+ * Gestures support
+ *
+ * The prototypes swipeWithEvent, beginGestureWithEvent, smartMagnifyWithEvent,
+ * rotateWithEvent and endGestureWithEvent were obtained from the following
+ * links:
+ * https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/ApplicationKit/Classes/NSResponder_Class/Reference/Reference.html
+ * https://developer.apple.com/library/mac/#releasenotes/Cocoa/AppKit.html
+ */
+- (void)swipeWithEvent:(NSEvent*)anEvent;
+- (void)beginGestureWithEvent:(NSEvent*)anEvent;
+- (void)magnifyWithEvent:(NSEvent*)anEvent;
+- (void)smartMagnifyWithEvent:(NSEvent*)anEvent;
+- (void)rotateWithEvent:(NSEvent*)anEvent;
+- (void)endGestureWithEvent:(NSEvent*)anEvent;
+
+- (void)scrollWheel:(NSEvent*)anEvent;
+
+- (void)setUsingOMTCompositor:(BOOL)aUseOMTC;
+
+- (NSEvent*)lastKeyDownEvent;
+
++ (uint32_t)sUniqueKeyEventId;
+
++ (NSMutableDictionary*)sNativeKeyEventsMap;
+@end
+
+class ChildViewMouseTracker {
+ public:
+  static void MouseMoved(NSEvent* aEvent);
+  static void MouseScrolled(NSEvent* aEvent);
+  static void OnDestroyView(ChildView* aView);
+  static void OnDestroyWindow(NSWindow* aWindow);
+  static BOOL WindowAcceptsEvent(NSWindow* aWindow, NSEvent* aEvent,
+                                 ChildView* aView, BOOL isClickThrough = NO);
+  static void MouseExitedWindow(NSEvent* aEvent);
+  static void MouseEnteredWindow(NSEvent* aEvent);
+  static void NativeMenuOpened();
+  static void NativeMenuClosed();
+  static void ReEvaluateMouseEnterState(NSEvent* aEvent = nil,
+                                        ChildView* aOldView = nil);
+  static void ResendLastMouseMoveEvent();
+  static ChildView* ViewForEvent(NSEvent* aEvent);
+
+  static ChildView* sLastMouseEventView;
+  static NSEvent* sLastMouseMoveEvent;
+  static NSWindow* sWindowUnderMouse;
+  static NSPoint sLastScrollEventScreenLocation;
+};
+
+//-------------------------------------------------------------------------
+//
+// nsChildView
+//
+//-------------------------------------------------------------------------
+
+class nsChildView final : public nsBaseWidget {
+ private:
+  typedef nsBaseWidget Inherited;
+  typedef mozilla::layers::IAPZCTreeManager IAPZCTreeManager;
+
+ public:
+  nsChildView();
+
+  // nsIWidget interface
+  [[nodiscard]] virtual nsresult Create(nsIWidget* aParent,
+                                        nsNativeWidget aNativeParent,
+                                        const LayoutDeviceIntRect& aRect,
+                                        InitData* = nullptr) override;
+
+  virtual void Destroy() override;
+
+  virtual void Show(bool aState) override;
+  virtual bool IsVisible() const override;
+
+  virtual void SetParent(nsIWidget* aNewParent) override;
+  virtual nsIWidget* GetParent(void) override;
+  virtual float GetDPI() override;
+
+  virtual void Move(double aX, double aY) override;
+  virtual void Resize(double aWidth, double aHeight, bool aRepaint) override;
+  virtual void Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) override;
+
+  virtual void Enable(bool aState) override;
+  virtual bool IsEnabled() const override;
+
+  virtual nsSizeMode SizeMode() override { return mSizeMode; }
+  virtual void SetSizeMode(nsSizeMode aMode) override { mSizeMode = aMode; }
+
+  virtual void SetFocus(Raise, mozilla::dom::CallerType aCallerType) override;
+  virtual LayoutDeviceIntRect GetBounds() override;
+  virtual LayoutDeviceIntRect GetClientBounds() override;
+  virtual LayoutDeviceIntRect GetScreenBounds() override;
+
+  // Refresh mBounds with up-to-date values from [mView frame].
+  // Only called if this nsChildView is the popup content view of a popup
+  // window. For popup windows, the nsIWidget interface to Gecko is provided by
+  // nsCocoaWindow, not by nsChildView. So nsCocoaWindow manages resize requests
+  // from Gecko, fires resize events, and resizes the native NSWindow and
+  // NSView.
+  void UpdateBoundsFromView();
+
+  // Returns the "backing scale factor" of the view's window, which is the
+  // ratio of pixels in the window's backing store to Cocoa points. Prior to
+  // HiDPI support in OS X 10.7, this was always 1.0, but in HiDPI mode it
+  // will be 2.0 (and might potentially other values as screen resolutions
+  // evolve). This gives the relationship between what Gecko calls "device
+  // pixels" and the Cocoa "points" coordinate system.
+  CGFloat BackingScaleFactor() const;
+
+  mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale() final {
+    return mozilla::DesktopToLayoutDeviceScale(BackingScaleFactor());
+  }
+
+  // Call if the window's backing scale factor changes - i.e., it is moved
+  // between HiDPI and non-HiDPI screens
+  void BackingScaleFactorChanged();
+
+  virtual double GetDefaultScaleInternal() override;
+
+  virtual int32_t RoundsWidgetCoordinatesTo() override;
+
+  virtual void Invalidate(const LayoutDeviceIntRect& aRect) override;
+  void EnsureContentLayerForMainThreadPainting();
+
+  virtual void* GetNativeData(uint32_t aDataType) override;
+  virtual LayoutDeviceIntPoint WidgetToScreenOffset() override;
+  virtual bool ShowsResizeIndicator(
+      LayoutDeviceIntRect* aResizerRect) override {
+    return false;
+  }
+
+  virtual nsresult DispatchEvent(mozilla::WidgetGUIEvent* aEvent,
+                                 nsEventStatus& aStatus) override;
+
+  virtual bool WidgetTypeSupportsAcceleration() override;
+  virtual bool ShouldUseOffMainThreadCompositing() override;
+
+  virtual void SetCursor(const Cursor&) override;
+
+  virtual nsresult SetTitle(const nsAString& title) override;
+
+  [[nodiscard]] virtual nsresult GetAttention(int32_t aCycleCount) override;
+
+  virtual bool HasPendingInputEvent() override;
+
+  bool SendEventToNativeMenuSystem(NSEvent* aEvent);
+  virtual void PostHandleKeyEvent(
+      mozilla::WidgetKeyboardEvent* aEvent) override;
+  virtual nsresult ActivateNativeMenuItemAt(
+      const nsAString& indexString) override;
+  virtual nsresult ForceUpdateNativeMenuAt(
+      const nsAString& indexString) override;
+  [[nodiscard]] virtual nsresult GetSelectionAsPlaintext(
+      nsAString& aResult) override;
+
+  virtual void SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction) override;
+  virtual InputContext GetInputContext() override;
+  virtual TextEventDispatcherListener* GetNativeTextEventDispatcherListener()
+      override;
+  [[nodiscard]] virtual nsresult AttachNativeKeyEvent(
+      mozilla::WidgetKeyboardEvent& aEvent) override;
+  MOZ_CAN_RUN_SCRIPT virtual bool GetEditCommands(
+      mozilla::NativeKeyBindingsType aType,
+      const mozilla::WidgetKeyboardEvent& aEvent,
+      nsTArray<mozilla::CommandInt>& aCommands) override;
+
+  virtual void SuppressAnimation(bool aSuppress) override;
+
+  virtual nsresult SynthesizeNativeKeyEvent(
+      int32_t aNativeKeyboardLayout, int32_t aNativeKeyCode,
+      uint32_t aModifierFlags, const nsAString& aCharacters,
+      const nsAString& aUnmodifiedCharacters, nsIObserver* aObserver) override;
+
+  virtual nsresult SynthesizeNativeMouseEvent(
+      LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+      mozilla::MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+      nsIObserver* aObserver) override;
+
+  virtual nsresult SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
+                                             nsIObserver* aObserver) override {
+    return SynthesizeNativeMouseEvent(
+        aPoint, NativeMouseMessage::Move, mozilla::MouseButton::eNotPressed,
+        nsIWidget::Modifiers::NO_MODIFIERS, aObserver);
+  }
+  virtual nsresult SynthesizeNativeMouseScrollEvent(
+      LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage, double aDeltaX,
+      double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+      uint32_t aAdditionalFlags, nsIObserver* aObserver) override;
+  virtual nsresult SynthesizeNativeTouchPoint(uint32_t aPointerId,
+                                              TouchPointerState aPointerState,
+                                              LayoutDeviceIntPoint aPoint,
+                                              double aPointerPressure,
+                                              uint32_t aPointerOrientation,
+                                              nsIObserver* aObserver) override;
+
+  virtual nsresult SynthesizeNativeTouchpadDoubleTap(
+      LayoutDeviceIntPoint aPoint, uint32_t aModifierFlags) override;
+
+  // Mac specific methods
+  void WillPaintWindow();
+  bool PaintWindow(LayoutDeviceIntRegion aRegion);
+  bool PaintWindowInDrawTarget(mozilla::gfx::DrawTarget* aDT,
+                               const LayoutDeviceIntRegion& aRegion,
+                               const mozilla::gfx::IntSize& aSurfaceSize);
+
+  void PaintWindowInContentLayer();
+  void HandleMainThreadCATransaction();
+
+#ifdef ACCESSIBILITY
+  already_AddRefed<mozilla::a11y::LocalAccessible> GetDocumentAccessible();
+#endif
+
+  virtual void CreateCompositor() override;
+
+  virtual bool WidgetPaintsBackground() override { return true; }
+
+  virtual bool PreRender(
+      mozilla::widget::WidgetRenderingContext* aContext) override;
+  virtual void PostRender(
+      mozilla::widget::WidgetRenderingContext* aContext) override;
+  virtual RefPtr<mozilla::layers::NativeLayerRoot> GetNativeLayerRoot()
+      override;
+
+  virtual void UpdateThemeGeometries(
+      const nsTArray<ThemeGeometry>& aThemeGeometries) override;
+
+  virtual void UpdateWindowDraggingRegion(
+      const LayoutDeviceIntRegion& aRegion) override;
+  LayoutDeviceIntRegion GetNonDraggableRegion() {
+    return mNonDraggableRegion.Region();
+  }
+
+  virtual void LookUpDictionary(
+      const nsAString& aText,
+      const nsTArray<mozilla::FontRange>& aFontRangeArray,
+      const bool aIsVertical, const LayoutDeviceIntPoint& aPoint) override;
+
+  void ResetParent();
+
+  static bool DoHasPendingInputEvent();
+  static uint32_t GetCurrentInputEventCount();
+  static void UpdateCurrentInputEventCount();
+
+  NSView<mozView>* GetEditorView();
+
+  nsCocoaWindow* GetAppWindowWidget() const;
+
+  virtual void ReparentNativeWidget(nsIWidget* aNewParent) override;
+
+  mozilla::widget::TextInputHandler* GetTextInputHandler() {
+    return mTextInputHandler;
+  }
+
+  // unit conversion convenience functions
+  int32_t CocoaPointsToDevPixels(CGFloat aPts) const {
+    return nsCocoaUtils::CocoaPointsToDevPixels(aPts, BackingScaleFactor());
+  }
+  LayoutDeviceIntPoint CocoaPointsToDevPixels(const NSPoint& aPt) const {
+    return nsCocoaUtils::CocoaPointsToDevPixels(aPt, BackingScaleFactor());
+  }
+  LayoutDeviceIntPoint CocoaPointsToDevPixelsRoundDown(
+      const NSPoint& aPt) const {
+    return nsCocoaUtils::CocoaPointsToDevPixelsRoundDown(aPt,
+                                                         BackingScaleFactor());
+  }
+  LayoutDeviceIntRect CocoaPointsToDevPixels(const NSRect& aRect) const {
+    return nsCocoaUtils::CocoaPointsToDevPixels(aRect, BackingScaleFactor());
+  }
+  CGFloat DevPixelsToCocoaPoints(int32_t aPixels) const {
+    return nsCocoaUtils::DevPixelsToCocoaPoints(aPixels, BackingScaleFactor());
+  }
+  NSRect DevPixelsToCocoaPoints(const LayoutDeviceIntRect& aRect) const {
+    return nsCocoaUtils::DevPixelsToCocoaPoints(aRect, BackingScaleFactor());
+  }
+
+  virtual LayoutDeviceIntPoint GetClientOffset() override;
+
+  void DispatchAPZWheelInputEvent(mozilla::InputData& aEvent);
+  nsEventStatus DispatchAPZInputEvent(mozilla::InputData& aEvent);
+
+  void DispatchDoubleTapGesture(mozilla::TimeStamp aEventTimeStamp,
+                                LayoutDeviceIntPoint aScreenPosition,
+                                mozilla::Modifiers aModifiers);
+
+  // Called when the main thread enters a phase during which visual changes
+  // are imminent and any layer updates on the compositor thread would interfere
+  // with visual atomicity.
+  // "Async" CATransactions are CATransactions which happen on a thread that's
+  // not the main thread.
+  void SuspendAsyncCATransactions();
+
+  // Called when we know that the current main thread paint will be completed
+  // once the main thread goes back to the event loop.
+  void MaybeScheduleUnsuspendAsyncCATransactions();
+
+  // Called from the runnable dispatched by
+  // MaybeScheduleUnsuspendAsyncCATransactions(). At this point we know that the
+  // main thread is done handling the visual change (such as a window resize)
+  // and we can start modifying CALayers from the compositor thread again.
+  void UnsuspendAsyncCATransactions();
+
+  // Called by nsCocoaWindow when the window's fullscreen state changes.
+  void UpdateFullscreen(bool aFullscreen);
+
+#ifdef DEBUG
+  // test only.
+  virtual nsresult SetHiDPIMode(bool aHiDPI) override;
+  virtual nsresult RestoreHiDPIMode() override;
+#endif
+
+ protected:
+  virtual ~nsChildView();
+
+  void ReportMoveEvent();
+  void ReportSizeEvent();
+
+  void TearDownView();
+
+  virtual already_AddRefed<nsIWidget> AllocateChildPopupWidget() override {
+    return nsIWidget::CreateTopLevelWindow();
+  }
+
+  void ConfigureAPZCTreeManager() override;
+  void ConfigureAPZControllerThread() override;
+
+  void UpdateVibrancy(const nsTArray<ThemeGeometry>& aThemeGeometries);
+  mozilla::VibrancyManager& EnsureVibrancyManager();
+
+  nsIWidget* GetWidgetForListenerEvents();
+
+ protected:
+  ChildView* mView;  // my parallel cocoa view, [STRONG]
+  RefPtr<mozilla::widget::TextInputHandler> mTextInputHandler;
+  InputContext mInputContext;
+
+  NSView* mParentView;
+  nsIWidget* mParentWidget;
+
+#ifdef ACCESSIBILITY
+  // weak ref to this childview's associated mozAccessible for speed reasons
+  // (we get queried for it *a lot* but don't want to own it)
+  nsWeakPtr mAccessible;
+#endif
+
+  // Held while the compositor (or WR renderer) thread is compositing.
+  // Protects from tearing down the view during compositing and from presenting
+  // half-composited layers to the screen.
+  mozilla::Mutex mCompositingLock MOZ_UNANNOTATED;
+
+  mozilla::ViewRegion mNonDraggableRegion;
+
+  // Cached value of [mView backingScaleFactor], to avoid sending two obj-c
+  // messages (respondsToSelector, backingScaleFactor) every time we need to
+  // use it.
+  // ** We'll need to reinitialize this if the backing resolution changes. **
+  mutable CGFloat mBackingScaleFactor;
+
+  bool mVisible;
+  nsSizeMode mSizeMode;
+  bool mDrawing;
+  bool mIsDispatchPaint;  // Is a paint event being dispatched
+
+  RefPtr<mozilla::layers::NativeLayerRootCA> mNativeLayerRoot;
+
+  // In BasicLayers mode, this is the CoreAnimation layer that contains the
+  // rendering from Gecko. It is a sublayer of mNativeLayerRoot's underlying
+  // wrapper layer.
+  // Lazily created by EnsureContentLayerForMainThreadPainting().
+  RefPtr<mozilla::layers::NativeLayerCA> mContentLayer;
+  RefPtr<mozilla::layers::SurfacePoolHandle> mPoolHandle;
+
+  // In BasicLayers mode, this is the invalid region of mContentLayer.
+  LayoutDeviceIntRegion mContentLayerInvalidRegion;
+
+  mozilla::UniquePtr<mozilla::VibrancyManager> mVibrancyManager;
+
+  RefPtr<mozilla::CancelableRunnable> mUnsuspendAsyncCATransactionsRunnable;
+
+  static uint32_t sLastInputEventCount;
+
+  // This is used by SynthesizeNativeTouchPoint to maintain state between
+  // multiple synthesized points
+  mozilla::UniquePtr<mozilla::MultiTouchInput> mSynthesizedTouchInput;
+};
+
+#endif  // nsChildView_h_
diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
new file mode 100644
index 0000000000..79919ba69a
--- /dev/null
+++ b/widget/cocoa/nsChildView.mm
@@ -0,0 +1,5159 @@
+/* -*- Mode: objc; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+
+#include "mozilla/Logging.h"
+#include "mozilla/Unused.h"
+
+#include <unistd.h>
+#include <math.h>
+
+#include "nsChildView.h"
+#include "nsCocoaWindow.h"
+
+#include "mozilla/Maybe.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/SwipeTracker.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/TouchEvents.h"
+#include "mozilla/WheelHandlingHelper.h"  // for WheelDeltaAdjustmentStrategy
+#include "mozilla/WritingModes.h"
+#include "mozilla/dom/DataTransfer.h"
+#include "mozilla/dom/MouseEventBinding.h"
+#include "mozilla/dom/SimpleGestureEventBinding.h"
+#include "mozilla/dom/WheelEventBinding.h"
+
+#include "nsArrayUtils.h"
+#include "nsExceptionHandler.h"
+#include "nsObjCExceptions.h"
+#include "nsCOMPtr.h"
+#include "nsThreadUtils.h"
+#include "nsToolkit.h"
+#include "nsCRT.h"
+
+#include "nsFontMetrics.h"
+#include "nsIRollupListener.h"
+#include "nsViewManager.h"
+#include "nsIFile.h"
+#include "nsILocalFileMac.h"
+#include "nsGfxCIID.h"
+#include "nsStyleConsts.h"
+#include "nsIWidgetListener.h"
+#include "nsIScreen.h"
+
+#include "nsDragService.h"
+#include "nsClipboard.h"
+#include "nsCursorManager.h"
+#include "nsWindowMap.h"
+#include "nsCocoaUtils.h"
+#include "nsMenuUtilsX.h"
+#include "nsMenuBarX.h"
+#include "NativeKeyBindings.h"
+#include "MacThemeGeometryType.h"
+
+#include "gfxContext.h"
+#include "gfxQuartzSurface.h"
+#include "gfxUtils.h"
+#include "nsRegion.h"
+#include "GfxTexturesReporter.h"
+#include "GLTextureImage.h"
+#include "GLContextProvider.h"
+#include "GLContextCGL.h"
+#include "OGLShaderProgram.h"
+#include "ScopedGLHelpers.h"
+#include "HeapCopyOfStackArray.h"
+#include "mozilla/layers/IAPZCTreeManager.h"
+#include "mozilla/layers/APZInputBridge.h"
+#include "mozilla/layers/APZThreadUtils.h"
+#include "mozilla/layers/CompositorOGL.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+#include "mozilla/layers/InputAPZContext.h"
+#include "mozilla/layers/IpcResourceUpdateQueue.h"
+#include "mozilla/layers/NativeLayerCA.h"
+#include "mozilla/layers/WebRenderBridgeChild.h"
+#include "mozilla/layers/WebRenderLayerManager.h"
+#include "mozilla/webrender/WebRenderAPI.h"
+#include "mozilla/widget/CompositorWidget.h"
+#include "mozilla/widget/Screen.h"
+#include "gfxUtils.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/BorrowedContext.h"
+#ifdef ACCESSIBILITY
+#  include "nsAccessibilityService.h"
+#  include "mozilla/a11y/Platform.h"
+#endif
+
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_apz.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/StaticPrefs_general.h"
+#include "mozilla/StaticPrefs_gfx.h"
+#include "mozilla/StaticPrefs_ui.h"
+
+#include <dlfcn.h>
+
+#include <ApplicationServices/ApplicationServices.h>
+
+#include "GeckoProfiler.h"
+
+#include "mozilla/layers/ChromeProcessController.h"
+#include "nsLayoutUtils.h"
+#include "InputData.h"
+#include "VibrancyManager.h"
+#include "nsNativeThemeCocoa.h"
+#include "nsIDOMWindowUtils.h"
+#include "Units.h"
+#include "UnitTransforms.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "CustomCocoaEvents.h"
+#include "NativeMenuSupport.h"
+
+using namespace mozilla;
+using namespace mozilla::layers;
+using namespace mozilla::gl;
+using namespace mozilla::widget;
+
+using mozilla::gfx::Matrix4x4;
+
+#undef DEBUG_UPDATE
+#undef INVALIDATE_DEBUGGING  // flash areas as they are invalidated
+
+// Don't put more than this many rects in the dirty region, just fluff
+// out to the bounding-box if there are more
+#define MAX_RECTS_IN_REGION 100
+
+LazyLogModule sCocoaLog("nsCocoaWidgets");
+
+extern "C" {
+CG_EXTERN void CGContextResetCTM(CGContextRef);
+CG_EXTERN void CGContextSetCTM(CGContextRef, CGAffineTransform);
+CG_EXTERN void CGContextResetClip(CGContextRef);
+
+typedef CFTypeRef CGSRegionObj;
+CGError CGSNewRegionWithRect(const CGRect* rect, CGSRegionObj* outRegion);
+CGError CGSNewRegionWithRectList(const CGRect* rects, int rectCount,
+                                 CGSRegionObj* outRegion);
+}
+
+// defined in nsMenuBarX.mm
+extern NSMenu* sApplicationMenu;  // Application menu shared by all menubars
+
+extern nsIArray* gDraggedTransferables;
+
+ChildView* ChildViewMouseTracker::sLastMouseEventView = nil;
+NSEvent* ChildViewMouseTracker::sLastMouseMoveEvent = nil;
+NSWindow* ChildViewMouseTracker::sWindowUnderMouse = nil;
+NSPoint ChildViewMouseTracker::sLastScrollEventScreenLocation = NSZeroPoint;
+
+#ifdef INVALIDATE_DEBUGGING
+static void blinkRect(Rect* r);
+static void blinkRgn(RgnHandle rgn);
+#endif
+
+bool gUserCancelledDrag = false;
+
+uint32_t nsChildView::sLastInputEventCount = 0;
+
+static bool sIsTabletPointerActivated = false;
+
+static uint32_t sUniqueKeyEventId = 0;
+
+// The view that will do our drawing or host our NSOpenGLContext or Core
+// Animation layer.
+@interface PixelHostingView : NSView {
+}
+
+@end
+
+@interface ChildView (Private)
+
+// sets up our view, attaching it to its owning gecko view
+- (id)initWithFrame:(NSRect)inFrame geckoChild:(nsChildView*)inChild;
+
+// set up a gecko mouse event based on a cocoa mouse event
+- (void)convertCocoaMouseWheelEvent:(NSEvent*)aMouseEvent
+                       toGeckoEvent:(WidgetWheelEvent*)outWheelEvent;
+- (void)convertCocoaMouseEvent:(NSEvent*)aMouseEvent
+                  toGeckoEvent:(WidgetInputEvent*)outGeckoEvent;
+- (void)convertCocoaTabletPointerEvent:(NSEvent*)aMouseEvent
+                          toGeckoEvent:(WidgetMouseEvent*)outGeckoEvent;
+- (NSMenu*)contextMenu;
+
+- (void)markLayerForDisplay;
+- (CALayer*)rootCALayer;
+- (void)updateRootCALayer;
+
+#ifdef ACCESSIBILITY
+- (id<mozAccessible>)accessible;
+#endif
+
+- (LayoutDeviceIntPoint)convertWindowCoordinates:(NSPoint)aPoint;
+- (LayoutDeviceIntPoint)convertWindowCoordinatesRoundDown:(NSPoint)aPoint;
+
+- (BOOL)inactiveWindowAcceptsMouseEvent:(NSEvent*)aEvent;
+- (void)updateWindowDraggableState;
+
+- (bool)beginOrEndGestureForEventPhase:(NSEvent*)aEvent;
+
+@end
+
+#pragma mark -
+
+// Flips a screen coordinate from a point in the cocoa coordinate system
+// (bottom-left rect) to a point that is a "flipped" cocoa coordinate system
+// (starts in the top-left).
+static inline void FlipCocoaScreenCoordinate(NSPoint& inPoint) {
+  inPoint.y = nsCocoaUtils::FlippedScreenY(inPoint.y);
+}
+
+#pragma mark -
+
+nsChildView::nsChildView()
+    : nsBaseWidget(),
+      mView(nullptr),
+      mParentView(nil),
+      mParentWidget(nullptr),
+      mCompositingLock("ChildViewCompositing"),
+      mBackingScaleFactor(0.0),
+      mVisible(false),
+      mSizeMode(nsSizeMode_Normal),
+      mDrawing(false),
+      mIsDispatchPaint(false) {}
+
+nsChildView::~nsChildView() {
+  // Notify the children that we're gone.  childView->ResetParent() can change
+  // our list of children while it's being iterated, so the way we iterate the
+  // list must allow for this.
+  for (nsIWidget* kid = mLastChild; kid;) {
+    nsChildView* childView = static_cast<nsChildView*>(kid);
+    kid = kid->GetPrevSibling();
+    childView->ResetParent();
+  }
+
+  NS_WARNING_ASSERTION(
+      mOnDestroyCalled,
+      "nsChildView object destroyed without calling Destroy()");
+
+  if (mContentLayer) {
+    mNativeLayerRoot->RemoveLayer(mContentLayer);  // safe if already removed
+  }
+
+  DestroyCompositor();
+
+  // An nsChildView object that was in use can be destroyed without Destroy()
+  // ever being called on it.  So we also need to do a quick, safe cleanup
+  // here (it's too late to just call Destroy(), which can cause crashes).
+  // It's particularly important to make sure widgetDestroyed is called on our
+  // mView -- this method NULLs mView's mGeckoChild, and NULL checks on
+  // mGeckoChild are used throughout the ChildView class to tell if it's safe
+  // to use a ChildView object.
+  [mView widgetDestroyed];  // Safe if mView is nil.
+  mParentWidget = nil;
+  TearDownView();  // Safe if called twice.
+}
+
+nsresult nsChildView::Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                             const LayoutDeviceIntRect& aRect,
+                             widget::InitData* aInitData) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Because the hidden window is created outside of an event loop,
+  // we need to provide an autorelease pool to avoid leaking cocoa objects
+  // (see bug 559075).
+  nsAutoreleasePool localPool;
+
+  mBounds = aRect;
+
+  // Ensure that the toolkit is created.
+  nsToolkit::GetToolkit();
+
+  BaseCreate(aParent, aInitData);
+
+  mParentView = nil;
+  if (aParent) {
+    // This is the popup window case. aParent is the nsCocoaWindow for the
+    // popup window, and mParentView will be its content view.
+    mParentView = (NSView*)aParent->GetNativeData(NS_NATIVE_WIDGET);
+    mParentWidget = aParent;
+  } else {
+    // This is the top-level window case.
+    // aNativeParent will be the contentView of our window, since that's what
+    // nsCocoaWindow returns when asked for an NS_NATIVE_VIEW.
+    // We do not have a direct "parent widget" association with the top level
+    // window's nsCocoaWindow object.
+    mParentView = reinterpret_cast<NSView*>(aNativeParent);
+  }
+
+  // create our parallel NSView and hook it up to our parent. Recall
+  // that NS_NATIVE_WIDGET is the NSView.
+  CGFloat scaleFactor = nsCocoaUtils::GetBackingScaleFactor(mParentView);
+  NSRect r = nsCocoaUtils::DevPixelsToCocoaPoints(mBounds, scaleFactor);
+  mView = [[ChildView alloc] initWithFrame:r geckoChild:this];
+
+  mNativeLayerRoot = NativeLayerRootCA::CreateForCALayer([mView rootCALayer]);
+  mNativeLayerRoot->SetBackingScale(scaleFactor);
+
+  // If this view was created in a Gecko view hierarchy, the initial state
+  // is hidden.  If the view is attached only to a native NSView but has
+  // no Gecko parent (as in embedding), the initial state is visible.
+  if (mParentWidget)
+    [mView setHidden:YES];
+  else
+    mVisible = true;
+
+  // Hook it up in the NSView hierarchy.
+  if (mParentView) {
+    [mParentView addSubview:mView];
+  }
+
+  // if this is a ChildView, make sure that our per-window data
+  // is set up
+  if ([mView isKindOfClass:[ChildView class]])
+    [[WindowDataMap sharedWindowDataMap] ensureDataForWindow:[mView window]];
+
+  NS_ASSERTION(!mTextInputHandler, "mTextInputHandler has already existed");
+  mTextInputHandler = new TextInputHandler(this, mView);
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void nsChildView::TearDownView() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mView) return;
+
+  NSWindow* win = [mView window];
+  NSResponder* responder = [win firstResponder];
+
+  // We're being unhooked from the view hierarchy, don't leave our view
+  // or a child view as the window first responder.
+  if (responder && [responder isKindOfClass:[NSView class]] &&
+      [(NSView*)responder isDescendantOf:mView]) {
+    [win makeFirstResponder:[mView superview]];
+  }
+
+  // If mView is win's contentView, win (mView's NSWindow) "owns" mView --
+  // win has retained mView, and will detach it from the view hierarchy and
+  // release it when necessary (when win is itself destroyed (in a call to
+  // [win dealloc])).  So all we need to do here is call [mView release] (to
+  // match the call to [mView retain] in nsChildView::StandardCreate()).
+  // Also calling [mView removeFromSuperviewWithoutNeedingDisplay] causes
+  // mView to be released again and dealloced, while remaining win's
+  // contentView.  So if we do that here, win will (for a short while) have
+  // an invalid contentView (for the consequences see bmo bugs 381087 and
+  // 374260).
+  if ([mView isEqual:[win contentView]]) {
+    [mView release];
+  } else {
+    // Stop NSView hierarchy being changed during [ChildView drawRect:]
+    [mView performSelectorOnMainThread:@selector(delayedTearDown)
+                            withObject:nil
+                         waitUntilDone:false];
+  }
+  mView = nil;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+nsCocoaWindow* nsChildView::GetAppWindowWidget() const {
+  id windowDelegate = [[mView window] delegate];
+  if (windowDelegate && [windowDelegate isKindOfClass:[WindowDelegate class]]) {
+    return [(WindowDelegate*)windowDelegate geckoWidget];
+  }
+  return nullptr;
+}
+
+void nsChildView::Destroy() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mOnDestroyCalled) return;
+  mOnDestroyCalled = true;
+
+  // Stuff below may delete the last ref to this
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
+
+  {
+    // Make sure that no composition is in progress while disconnecting
+    // ourselves from the view.
+    MutexAutoLock lock(mCompositingLock);
+
+    [mView widgetDestroyed];
+  }
+
+  nsBaseWidget::Destroy();
+
+  NotifyWindowDestroyed();
+  mParentWidget = nil;
+
+  TearDownView();
+
+  nsBaseWidget::OnDestroy();
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+#pragma mark -
+
+#if 0
+static void PrintViewHierarchy(NSView *view)
+{
+  while (view) {
+    NSLog(@"  view is %x, frame %@", view, NSStringFromRect([view frame]));
+    view = [view superview];
+  }
+}
+#endif
+
+// Return native data according to aDataType
+void* nsChildView::GetNativeData(uint32_t aDataType) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  void* retVal = nullptr;
+
+  switch (aDataType) {
+    case NS_NATIVE_WIDGET:
+      retVal = (void*)mView;
+      break;
+
+    case NS_NATIVE_WINDOW:
+      retVal = [mView window];
+      break;
+
+    case NS_NATIVE_GRAPHIC:
+      NS_ERROR("Requesting NS_NATIVE_GRAPHIC on a Mac OS X child view!");
+      retVal = nullptr;
+      break;
+
+    case NS_NATIVE_OFFSETX:
+      retVal = 0;
+      break;
+
+    case NS_NATIVE_OFFSETY:
+      retVal = 0;
+      break;
+
+    case NS_RAW_NATIVE_IME_CONTEXT:
+      retVal = GetPseudoIMEContext();
+      if (retVal) {
+        break;
+      }
+      retVal = [mView inputContext];
+      // If input context isn't available on this widget, we should set |this|
+      // instead of nullptr since if this returns nullptr, IMEStateManager
+      // cannot manage composition with TextComposition instance.  Although,
+      // this case shouldn't occur.
+      if (NS_WARN_IF(!retVal)) {
+        retVal = this;
+      }
+      break;
+
+    case NS_NATIVE_WINDOW_WEBRTC_DEVICE_ID: {
+      NSWindow* win = [mView window];
+      if (win) {
+        retVal = (void*)[win windowNumber];
+      }
+      break;
+    }
+  }
+
+  return retVal;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nullptr);
+}
+
+#pragma mark -
+
+void nsChildView::SuppressAnimation(bool aSuppress) {
+  GetAppWindowWidget()->SuppressAnimation(aSuppress);
+}
+
+bool nsChildView::IsVisible() const {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!mVisible) {
+    return mVisible;
+  }
+
+  if (!GetAppWindowWidget()->IsVisible()) {
+    return false;
+  }
+
+  // mVisible does not accurately reflect the state of a hidden tabbed view
+  // so verify that the view has a window as well
+  // then check native widget hierarchy visibility
+  return ([mView window] != nil) && !NSIsEmptyRect([mView visibleRect]);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
+
+// Some NSView methods (e.g. setFrame and setHidden) invalidate the view's
+// bounds in our window. However, we don't want these invalidations because
+// they are unnecessary and because they actually slow us down since we
+// block on the compositor inside drawRect.
+// When we actually need something invalidated, there will be an explicit call
+// to Invalidate from Gecko, so turning these automatic invalidations off
+// won't hurt us in the non-OMTC case.
+// The invalidations inside these NSView methods happen via a call to the
+// private method -[NSWindow _setNeedsDisplayInRect:]. Our BaseWindow
+// implementation of that method is augmented to let us ignore those calls
+// using -[BaseWindow disable/enableSetNeedsDisplay].
+static void ManipulateViewWithoutNeedingDisplay(NSView* aView,
+                                                void (^aCallback)()) {
+  BaseWindow* win = nil;
+  if ([[aView window] isKindOfClass:[BaseWindow class]]) {
+    win = (BaseWindow*)[aView window];
+  }
+  [win disableSetNeedsDisplay];
+  aCallback();
+  [win enableSetNeedsDisplay];
+}
+
+// Hide or show this component
+void nsChildView::Show(bool aState) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (aState != mVisible) {
+    // Provide an autorelease pool because this gets called during startup
+    // on the "hidden window", resulting in cocoa object leakage if there's
+    // no pool in place.
+    nsAutoreleasePool localPool;
+
+    ManipulateViewWithoutNeedingDisplay(mView, ^{
+      [mView setHidden:!aState];
+    });
+
+    mVisible = aState;
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Change the parent of this widget
+void nsChildView::SetParent(nsIWidget* aNewParent) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mOnDestroyCalled) return;
+
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
+
+  if (mParentWidget) {
+    mParentWidget->RemoveChild(this);
+  }
+
+  if (aNewParent) {
+    ReparentNativeWidget(aNewParent);
+  } else {
+    [mView removeFromSuperview];
+    mParentView = nil;
+  }
+
+  mParentWidget = aNewParent;
+
+  if (mParentWidget) {
+    mParentWidget->AddChild(this);
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsChildView::ReparentNativeWidget(nsIWidget* aNewParent) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_ASSERT(aNewParent, "null widget");
+
+  if (mOnDestroyCalled) return;
+
+  NSView<mozView>* newParentView =
+      (NSView<mozView>*)aNewParent->GetNativeData(NS_NATIVE_WIDGET);
+  NS_ENSURE_TRUE_VOID(newParentView);
+
+  // we hold a ref to mView, so this is safe
+  [mView removeFromSuperview];
+  mParentView = newParentView;
+  [mParentView addSubview:mView];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsChildView::ResetParent() {
+  if (!mOnDestroyCalled) {
+    if (mParentWidget) mParentWidget->RemoveChild(this);
+    if (mView) [mView removeFromSuperview];
+  }
+  mParentWidget = nullptr;
+}
+
+nsIWidget* nsChildView::GetParent() { return mParentWidget; }
+
+float nsChildView::GetDPI() {
+  float dpi = 96.0;
+  nsCOMPtr<nsIScreen> screen = GetWidgetScreen();
+  if (screen) {
+    screen->GetDpi(&dpi);
+  }
+  return dpi;
+}
+
+void nsChildView::Enable(bool aState) {}
+
+bool nsChildView::IsEnabled() const { return true; }
+
+void nsChildView::SetFocus(Raise, mozilla::dom::CallerType aCallerType) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSWindow* window = [mView window];
+  if (window) [window makeFirstResponder:mView];
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Override to set the cursor on the mac
+void nsChildView::SetCursor(const Cursor& aCursor) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if ([mView isDragInProgress]) {
+    return;  // Don't change the cursor during dragging.
+  }
+
+  nsBaseWidget::SetCursor(aCursor);
+
+  bool forceUpdate = mUpdateCursor;
+  mUpdateCursor = false;
+  if (mCustomCursorAllowed && NS_SUCCEEDED([[nsCursorManager sharedInstance]
+                                    setCustomCursor:aCursor
+                                  widgetScaleFactor:BackingScaleFactor()
+                                        forceUpdate:forceUpdate])) {
+    return;
+  }
+
+  [[nsCursorManager sharedInstance] setNonCustomCursor:aCursor];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+#pragma mark -
+
+// Get this component dimension
+LayoutDeviceIntRect nsChildView::GetBounds() {
+  return !mView ? mBounds : CocoaPointsToDevPixels([mView frame]);
+}
+
+LayoutDeviceIntRect nsChildView::GetClientBounds() {
+  LayoutDeviceIntRect rect = GetBounds();
+  if (!mParentWidget) {
+    // For top level widgets we want the position on screen, not the position
+    // of this view inside the window.
+    rect.MoveTo(WidgetToScreenOffset());
+  }
+  return rect;
+}
+
+LayoutDeviceIntRect nsChildView::GetScreenBounds() {
+  LayoutDeviceIntRect rect = GetBounds();
+  rect.MoveTo(WidgetToScreenOffset());
+  return rect;
+}
+
+double nsChildView::GetDefaultScaleInternal() { return BackingScaleFactor(); }
+
+CGFloat nsChildView::BackingScaleFactor() const {
+  if (mBackingScaleFactor > 0.0) {
+    return mBackingScaleFactor;
+  }
+  if (!mView) {
+    return 1.0;
+  }
+  mBackingScaleFactor = nsCocoaUtils::GetBackingScaleFactor(mView);
+  return mBackingScaleFactor;
+}
+
+void nsChildView::BackingScaleFactorChanged() {
+  CGFloat newScale = nsCocoaUtils::GetBackingScaleFactor(mView);
+
+  // ignore notification if it hasn't really changed (or maybe we have
+  // disabled HiDPI mode via prefs)
+  if (mBackingScaleFactor == newScale) {
+    return;
+  }
+
+  SuspendAsyncCATransactions();
+  mBackingScaleFactor = newScale;
+  NSRect frame = [mView frame];
+  mBounds = nsCocoaUtils::CocoaRectToGeckoRectDevPix(frame, newScale);
+
+  mNativeLayerRoot->SetBackingScale(mBackingScaleFactor);
+
+  if (mWidgetListener && !mWidgetListener->GetAppWindow()) {
+    if (PresShell* presShell = mWidgetListener->GetPresShell()) {
+      presShell->BackingScaleFactorChanged();
+    }
+  }
+}
+
+int32_t nsChildView::RoundsWidgetCoordinatesTo() {
+  if (BackingScaleFactor() == 2.0) {
+    return 2;
+  }
+  return 1;
+}
+
+// Move this component, aX and aY are in the parent widget coordinate system
+void nsChildView::Move(double aX, double aY) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  int32_t x = NSToIntRound(aX);
+  int32_t y = NSToIntRound(aY);
+
+  if (!mView || (mBounds.x == x && mBounds.y == y)) return;
+
+  mBounds.x = x;
+  mBounds.y = y;
+
+  ManipulateViewWithoutNeedingDisplay(mView, ^{
+    [mView setFrame:DevPixelsToCocoaPoints(mBounds)];
+  });
+
+  ReportMoveEvent();
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsChildView::Resize(double aWidth, double aHeight, bool aRepaint) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  int32_t width = NSToIntRound(aWidth);
+  int32_t height = NSToIntRound(aHeight);
+
+  if (!mView || (mBounds.width == width && mBounds.height == height)) return;
+
+  SuspendAsyncCATransactions();
+  mBounds.width = width;
+  mBounds.height = height;
+
+  ManipulateViewWithoutNeedingDisplay(mView, ^{
+    [mView setFrame:DevPixelsToCocoaPoints(mBounds)];
+  });
+
+  if (mVisible && aRepaint) {
+    [[mView pixelHostingView] setNeedsDisplay:YES];
+  }
+
+  ReportSizeEvent();
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsChildView::Resize(double aX, double aY, double aWidth, double aHeight,
+                         bool aRepaint) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  int32_t x = NSToIntRound(aX);
+  int32_t y = NSToIntRound(aY);
+  int32_t width = NSToIntRound(aWidth);
+  int32_t height = NSToIntRound(aHeight);
+
+  BOOL isMoving = (mBounds.x != x || mBounds.y != y);
+  BOOL isResizing = (mBounds.width != width || mBounds.height != height);
+  if (!mView || (!isMoving && !isResizing)) return;
+
+  if (isMoving) {
+    mBounds.x = x;
+    mBounds.y = y;
+  }
+  if (isResizing) {
+    SuspendAsyncCATransactions();
+    mBounds.width = width;
+    mBounds.height = height;
+
+    CALayer* layer = [mView rootCALayer];
+    double scale = BackingScaleFactor();
+    layer.bounds = CGRectMake(0, 0, width / scale, height / scale);
+  }
+
+  ManipulateViewWithoutNeedingDisplay(mView, ^{
+    [mView setFrame:DevPixelsToCocoaPoints(mBounds)];
+  });
+
+  if (mVisible && aRepaint) {
+    [[mView pixelHostingView] setNeedsDisplay:YES];
+  }
+
+  if (isMoving) {
+    ReportMoveEvent();
+    if (mOnDestroyCalled) return;
+  }
+  if (isResizing) ReportSizeEvent();
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// The following three methods are primarily an attempt to avoid glitches during
+// window resizing.
+// Here's some background on how these glitches come to be:
+// CoreAnimation transactions are per-thread. They don't nest across threads.
+// If you submit a transaction on the main thread and a transaction on a
+// different thread, the two will race to the window server and show up on the
+// screen in the order that they happen to arrive in at the window server.
+// When the window size changes, there's another event that needs to be
+// synchronized with: the window "shape" change. Cocoa has built-in
+// synchronization mechanics that make sure that *main thread* window paints
+// during window resizes are synchronized properly with the window shape change.
+// But no such built-in synchronization exists for CATransactions that are
+// triggered on a non-main thread. To cope with this, we define a "danger zone"
+// during which we simply avoid triggering any CATransactions on a non-main
+// thread (called "async" CATransactions here). This danger zone starts at the
+// earliest opportunity at which we know about the size change, which is
+// nsChildView::Resize, and ends at a point at which we know for sure that the
+// paint has been handled completely, which is when we return to the event loop
+// after layer display.
+void nsChildView::SuspendAsyncCATransactions() {
+  if (mUnsuspendAsyncCATransactionsRunnable) {
+    mUnsuspendAsyncCATransactionsRunnable->Cancel();
+    mUnsuspendAsyncCATransactionsRunnable = nullptr;
+  }
+
+  // Make sure that there actually will be a CATransaction on the main thread
+  // during which we get a chance to schedule unsuspension. Otherwise we might
+  // accidentally stay suspended indefinitely.
+  [mView markLayerForDisplay];
+
+  mNativeLayerRoot->SuspendOffMainThreadCommits();
+}
+
+void nsChildView::MaybeScheduleUnsuspendAsyncCATransactions() {
+  if (mNativeLayerRoot->AreOffMainThreadCommitsSuspended() &&
+      !mUnsuspendAsyncCATransactionsRunnable) {
+    mUnsuspendAsyncCATransactionsRunnable = NewCancelableRunnableMethod(
+        "nsChildView::MaybeScheduleUnsuspendAsyncCATransactions", this,
+        &nsChildView::UnsuspendAsyncCATransactions);
+    NS_DispatchToMainThread(mUnsuspendAsyncCATransactionsRunnable);
+  }
+}
+
+void nsChildView::UnsuspendAsyncCATransactions() {
+  mUnsuspendAsyncCATransactionsRunnable = nullptr;
+
+  if (mNativeLayerRoot->UnsuspendOffMainThreadCommits()) {
+    // We need to call mNativeLayerRoot->CommitToScreen() at the next available
+    // opportunity.
+    // The easiest way to handle this request is to mark the layer as needing
+    // display, because this will schedule a main thread CATransaction, during
+    // which HandleMainThreadCATransaction will call CommitToScreen().
+    [mView markLayerForDisplay];
+  }
+}
+
+void nsChildView::UpdateFullscreen(bool aFullscreen) {
+  if (mNativeLayerRoot) {
+    mNativeLayerRoot->SetWindowIsFullscreen(aFullscreen);
+  }
+}
+
+nsresult nsChildView::SynthesizeNativeKeyEvent(
+    int32_t aNativeKeyboardLayout, int32_t aNativeKeyCode,
+    uint32_t aModifierFlags, const nsAString& aCharacters,
+    const nsAString& aUnmodifiedCharacters, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "keyevent");
+  return mTextInputHandler->SynthesizeNativeKeyEvent(
+      aNativeKeyboardLayout, aNativeKeyCode, aModifierFlags, aCharacters,
+      aUnmodifiedCharacters);
+}
+
+nsresult nsChildView::SynthesizeNativeMouseEvent(
+    LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+    MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+    nsIObserver* aObserver) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  AutoObserverNotifier notifier(aObserver, "mouseevent");
+
+  NSPoint pt =
+      nsCocoaUtils::DevPixelsToCocoaPoints(aPoint, BackingScaleFactor());
+
+  // Move the mouse cursor to the requested position and reconnect it to the
+  // mouse.
+  CGWarpMouseCursorPosition(NSPointToCGPoint(pt));
+  CGAssociateMouseAndMouseCursorPosition(true);
+
+  // aPoint is given with the origin on the top left, but convertScreenToBase
+  // expects a point in a coordinate system that has its origin on the bottom
+  // left.
+  NSPoint screenPoint = NSMakePoint(pt.x, nsCocoaUtils::FlippedScreenY(pt.y));
+  NSPoint windowPoint =
+      nsCocoaUtils::ConvertPointFromScreen([mView window], screenPoint);
+  NSEventModifierFlags modifierFlags =
+      nsCocoaUtils::ConvertWidgetModifiersToMacModifierFlags(aModifierFlags);
+
+  if (aButton == MouseButton::eX1 || aButton == MouseButton::eX2) {
+    // NSEvent has `buttonNumber` for `NSEventTypeOther*`.  However, it seems
+    // that there is no way to specify it.  Therefore, we should return error
+    // for now.
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  NSEventType nativeEventType;
+  switch (aNativeMessage) {
+    case NativeMouseMessage::ButtonDown:
+    case NativeMouseMessage::ButtonUp: {
+      switch (aButton) {
+        case MouseButton::ePrimary:
+          nativeEventType = aNativeMessage == NativeMouseMessage::ButtonDown
+                                ? NSEventTypeLeftMouseDown
+                                : NSEventTypeLeftMouseUp;
+          break;
+        case MouseButton::eMiddle:
+          nativeEventType = aNativeMessage == NativeMouseMessage::ButtonDown
+                                ? NSEventTypeOtherMouseDown
+                                : NSEventTypeOtherMouseUp;
+          break;
+        case MouseButton::eSecondary:
+          nativeEventType = aNativeMessage == NativeMouseMessage::ButtonDown
+                                ? NSEventTypeRightMouseDown
+                                : NSEventTypeRightMouseUp;
+          break;
+        default:
+          return NS_ERROR_INVALID_ARG;
+      }
+      break;
+    }
+    case NativeMouseMessage::Move:
+      nativeEventType = NSEventTypeMouseMoved;
+      break;
+    case NativeMouseMessage::EnterWindow:
+      nativeEventType = NSEventTypeMouseEntered;
+      break;
+    case NativeMouseMessage::LeaveWindow:
+      nativeEventType = NSEventTypeMouseExited;
+      break;
+  }
+
+  NSEvent* event =
+      [NSEvent mouseEventWithType:nativeEventType
+                         location:windowPoint
+                    modifierFlags:modifierFlags
+                        timestamp:[[NSProcessInfo processInfo] systemUptime]
+                     windowNumber:[[mView window] windowNumber]
+                          context:nil
+                      eventNumber:0
+                       clickCount:1
+                         pressure:0.0];
+
+  if (!event) return NS_ERROR_FAILURE;
+
+  if ([[mView window] isKindOfClass:[BaseWindow class]]) {
+    // Tracking area events don't end up in their tracking areas when sent
+    // through [NSApp sendEvent:], so pass them directly to the right methods.
+    BaseWindow* window = (BaseWindow*)[mView window];
+    if (nativeEventType == NSEventTypeMouseEntered) {
+      [window mouseEntered:event];
+      return NS_OK;
+    }
+    if (nativeEventType == NSEventTypeMouseExited) {
+      [window mouseExited:event];
+      return NS_OK;
+    }
+    if (nativeEventType == NSEventTypeMouseMoved) {
+      [window mouseMoved:event];
+      return NS_OK;
+    }
+  }
+
+  [NSApp sendEvent:event];
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+nsresult nsChildView::SynthesizeNativeMouseScrollEvent(
+    mozilla::LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage,
+    double aDeltaX, double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+    uint32_t aAdditionalFlags, nsIObserver* aObserver) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  AutoObserverNotifier notifier(aObserver, "mousescrollevent");
+
+  NSPoint pt =
+      nsCocoaUtils::DevPixelsToCocoaPoints(aPoint, BackingScaleFactor());
+
+  // Move the mouse cursor to the requested position and reconnect it to the
+  // mouse.
+  CGWarpMouseCursorPosition(NSPointToCGPoint(pt));
+  CGAssociateMouseAndMouseCursorPosition(true);
+
+  // Mostly copied from http://stackoverflow.com/a/6130349
+  CGScrollEventUnit units =
+      (aAdditionalFlags & nsIDOMWindowUtils::MOUSESCROLL_SCROLL_LINES)
+          ? kCGScrollEventUnitLine
+          : kCGScrollEventUnitPixel;
+  CGEventRef cgEvent = CGEventCreateScrollWheelEvent(
+      NULL, units, 3, (int32_t)aDeltaY, (int32_t)aDeltaX, (int32_t)aDeltaZ);
+  if (!cgEvent) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (aNativeMessage) {
+    CGEventSetIntegerValueField(cgEvent, kCGScrollWheelEventScrollPhase,
+                                aNativeMessage);
+  }
+
+  // On macOS 10.14 and up CGEventPost won't work because of changes in macOS
+  // to improve security. This code makes an NSEvent corresponding to the
+  // wheel event and dispatches it directly to the scrollWheel handler. Some
+  // fiddling is needed with the coordinates in order to simulate what macOS
+  // would do; this code adapted from the Chromium equivalent function at
+  // https://chromium.googlesource.com/chromium/src.git/+/62.0.3178.1/ui/events/test/cocoa_test_event_utils.mm#38
+  CGPoint location = CGEventGetLocation(cgEvent);
+  location.y += NSMinY([[mView window] frame]);
+  location.x -= NSMinX([[mView window] frame]);
+  CGEventSetLocation(cgEvent, location);
+
+  uint64_t kNanosPerSec = 1000000000L;
+  CGEventSetTimestamp(
+      cgEvent, [[NSProcessInfo processInfo] systemUptime] * kNanosPerSec);
+
+  NSEvent* event = [NSEvent eventWithCGEvent:cgEvent];
+  [event setValue:[mView window] forKey:@"_window"];
+  [mView scrollWheel:event];
+
+  CFRelease(cgEvent);
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+nsresult nsChildView::SynthesizeNativeTouchPoint(
+    uint32_t aPointerId, TouchPointerState aPointerState,
+    mozilla::LayoutDeviceIntPoint aPoint, double aPointerPressure,
+    uint32_t aPointerOrientation, nsIObserver* aObserver) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  AutoObserverNotifier notifier(aObserver, "touchpoint");
+
+  MOZ_ASSERT(NS_IsMainThread());
+  if (aPointerState == TOUCH_HOVER) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (!mSynthesizedTouchInput) {
+    mSynthesizedTouchInput = MakeUnique<MultiTouchInput>();
+  }
+
+  LayoutDeviceIntPoint pointInWindow = aPoint - WidgetToScreenOffset();
+  MultiTouchInput inputToDispatch = UpdateSynthesizedTouchState(
+      mSynthesizedTouchInput.get(), TimeStamp::Now(), aPointerId, aPointerState,
+      pointInWindow, aPointerPressure, aPointerOrientation);
+  DispatchTouchInput(inputToDispatch);
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+nsresult nsChildView::SynthesizeNativeTouchpadDoubleTap(
+    mozilla::LayoutDeviceIntPoint aPoint, uint32_t aModifierFlags) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  DispatchDoubleTapGesture(TimeStamp::Now(), aPoint - WidgetToScreenOffset(),
+                           static_cast<Modifiers>(aModifierFlags));
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+bool nsChildView::SendEventToNativeMenuSystem(NSEvent* aEvent) {
+  bool handled = false;
+  nsCocoaWindow* widget = GetAppWindowWidget();
+  if (widget) {
+    nsMenuBarX* mb = widget->GetMenuBar();
+    if (mb) {
+      // Check if main menu wants to handle the event.
+      handled = mb->PerformKeyEquivalent(aEvent);
+    }
+  }
+
+  if (!handled && sApplicationMenu) {
+    // Check if application menu wants to handle the event.
+    handled = [sApplicationMenu performKeyEquivalent:aEvent];
+  }
+
+  return handled;
+}
+
+void nsChildView::PostHandleKeyEvent(mozilla::WidgetKeyboardEvent* aEvent) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // We always allow keyboard events to propagate to keyDown: but if they are
+  // not handled we give menu items a chance to act. This allows for handling of
+  // custom shortcuts. Note that existing shortcuts cannot be reassigned yet and
+  // will have been handled by keyDown: before we get here.
+  NSMutableDictionary* nativeKeyEventsMap = [ChildView sNativeKeyEventsMap];
+  NSEvent* cocoaEvent = [nativeKeyEventsMap objectForKey:@(aEvent->mUniqueId)];
+  if (!cocoaEvent) {
+    return;
+  }
+
+  // If the escape key is pressed, the expectations are as follows:
+  // 1. If the page is loading, interrupt loading.
+  // 2. Give a website an opportunity to handle the event and call
+  //    preventDefault() on it.
+  // 3. If the browser is fullscreen and the page isn't loading, exit
+  //    fullscreen.
+  // 4. Ignore.
+  // Case 1 and 2 are handled before we get here. Below, we handle case 3.
+  if (StaticPrefs::browser_fullscreen_exit_on_escape() &&
+      [cocoaEvent keyCode] == kVK_Escape &&
+      [[mView window] styleMask] & NSWindowStyleMaskFullScreen) {
+    [[mView window] toggleFullScreen:nil];
+  }
+
+  if (SendEventToNativeMenuSystem(cocoaEvent)) {
+    aEvent->PreventDefault();
+  }
+  [nativeKeyEventsMap removeObjectForKey:@(aEvent->mUniqueId)];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Used for testing native menu system structure and event handling.
+nsresult nsChildView::ActivateNativeMenuItemAt(const nsAString& indexString) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  nsMenuUtilsX::CheckNativeMenuConsistency([NSApp mainMenu]);
+
+  NSString* locationString =
+      [NSString stringWithCharacters:reinterpret_cast<const unichar*>(
+                                         indexString.BeginReading())
+                              length:indexString.Length()];
+  NSMenuItem* item = nsMenuUtilsX::NativeMenuItemWithLocation(
+      [NSApp mainMenu], locationString, true);
+  // We can't perform an action on an item with a submenu, that will raise
+  // an obj-c exception.
+  if (item && ![item hasSubmenu]) {
+    NSMenu* parent = [item menu];
+    if (parent) {
+      // NSLog(@"Performing action for native menu item titled: %@\n",
+      //       [[currentSubmenu itemAtIndex:targetIndex] title]);
+      mozilla::AutoRestore<bool> autoRestore(
+          nsMenuUtilsX::gIsSynchronouslyActivatingNativeMenuItemDuringTest);
+      nsMenuUtilsX::gIsSynchronouslyActivatingNativeMenuItemDuringTest = true;
+      [parent performActionForItemAtIndex:[parent indexOfItem:item]];
+      return NS_OK;
+    }
+  }
+  return NS_ERROR_FAILURE;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+// Used for testing native menu system structure and event handling.
+nsresult nsChildView::ForceUpdateNativeMenuAt(const nsAString& indexString) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  nsCocoaWindow* widget = GetAppWindowWidget();
+  if (widget) {
+    nsMenuBarX* mb = widget->GetMenuBar();
+    if (mb) {
+      if (indexString.IsEmpty())
+        mb->ForceNativeMenuReload();
+      else
+        mb->ForceUpdateNativeMenuAt(indexString);
+    }
+  }
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+#pragma mark -
+
+#ifdef INVALIDATE_DEBUGGING
+
+static Boolean KeyDown(const UInt8 theKey) {
+  KeyMap map;
+  GetKeys(map);
+  return ((*((UInt8*)map + (theKey >> 3)) >> (theKey & 7)) & 1) != 0;
+}
+
+static Boolean caps_lock() { return KeyDown(0x39); }
+
+static void blinkRect(Rect* r) {
+  StRegionFromPool oldClip;
+  if (oldClip != NULL) ::GetClip(oldClip);
+
+  ::ClipRect(r);
+  ::InvertRect(r);
+  UInt32 end = ::TickCount() + 5;
+  while (::TickCount() < end)
+    ;
+  ::InvertRect(r);
+
+  if (oldClip != NULL) ::SetClip(oldClip);
+}
+
+static void blinkRgn(RgnHandle rgn) {
+  StRegionFromPool oldClip;
+  if (oldClip != NULL) ::GetClip(oldClip);
+
+  ::SetClip(rgn);
+  ::InvertRgn(rgn);
+  UInt32 end = ::TickCount() + 5;
+  while (::TickCount() < end)
+    ;
+  ::InvertRgn(rgn);
+
+  if (oldClip != NULL) ::SetClip(oldClip);
+}
+
+#endif
+
+// Invalidate this component's visible area
+void nsChildView::Invalidate(const LayoutDeviceIntRect& aRect) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mView || !mVisible) return;
+
+  NS_ASSERTION(
+      GetWindowRenderer()->GetBackendType() != LayersBackend::LAYERS_WR,
+      "Shouldn't need to invalidate with accelerated OMTC layers!");
+
+  EnsureContentLayerForMainThreadPainting();
+  mContentLayerInvalidRegion.OrWith(aRect.Intersect(GetBounds()));
+  [mView markLayerForDisplay];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+bool nsChildView::WidgetTypeSupportsAcceleration() {
+  // All widget types support acceleration.
+  return true;
+}
+
+bool nsChildView::ShouldUseOffMainThreadCompositing() {
+  // We need to enable OMTC in popups which contain remote layer
+  // trees, since the remote content won't be rendered at all otherwise.
+  if (HasRemoteContent()) {
+    return true;
+  }
+
+  // Don't use OMTC for popup windows, because we do not want context menus to
+  // pay the overhead of starting up a compositor. With the OpenGL compositor,
+  // new windows are expensive because of shader re-compilation, and with
+  // WebRender, new windows are expensive because they create their own threads
+  // and texture caches.
+  // Using OMTC with BasicCompositor for context menus would probably be fine
+  // but isn't a well-tested configuration.
+  if ([mView window] && [[mView window] isKindOfClass:[PopupWindow class]]) {
+    // Use main-thread BasicLayerManager for drawing menus.
+    return false;
+  }
+
+  return nsBaseWidget::ShouldUseOffMainThreadCompositing();
+}
+
+#pragma mark -
+
+// Invokes callback and ProcessEvent methods on Event Listener object
+nsresult nsChildView::DispatchEvent(WidgetGUIEvent* event,
+                                    nsEventStatus& aStatus) {
+  RefPtr<nsChildView> kungFuDeathGrip(this);
+
+#ifdef DEBUG
+  debug_DumpEvent(stdout, event->mWidget, event, "something", 0);
+#endif
+
+  if (event->mFlags.mIsSynthesizedForTests) {
+    WidgetKeyboardEvent* keyEvent = event->AsKeyboardEvent();
+    if (keyEvent) {
+      nsresult rv = mTextInputHandler->AttachNativeKeyEvent(*keyEvent);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
+  aStatus = nsEventStatus_eIgnore;
+
+  nsIWidgetListener* listener = mWidgetListener;
+
+  // If the listener is NULL, check if the parent is a popup. If it is, then
+  // this child is the popup content view attached to a popup. Get the
+  // listener from the parent popup instead.
+  nsCOMPtr<nsIWidget> parentWidget = mParentWidget;
+  if (!listener && parentWidget) {
+    if (parentWidget->GetWindowType() == WindowType::Popup) {
+      // Check just in case event->mWidget isn't this widget
+      if (event->mWidget) {
+        listener = event->mWidget->GetWidgetListener();
+      }
+      if (!listener) {
+        event->mWidget = parentWidget;
+        listener = parentWidget->GetWidgetListener();
+      }
+    }
+  }
+
+  if (listener) aStatus = listener->HandleEvent(event, mUseAttachedEvents);
+
+  return NS_OK;
+}
+
+nsIWidget* nsChildView::GetWidgetForListenerEvents() {
+  // If there is no listener, use the parent popup's listener if that exists.
+  if (!mWidgetListener && mParentWidget &&
+      mParentWidget->GetWindowType() == WindowType::Popup) {
+    return mParentWidget;
+  }
+
+  return this;
+}
+
+void nsChildView::WillPaintWindow() {
+  nsCOMPtr<nsIWidget> widget = GetWidgetForListenerEvents();
+
+  nsIWidgetListener* listener = widget->GetWidgetListener();
+  if (listener) {
+    listener->WillPaintWindow(widget);
+  }
+}
+
+bool nsChildView::PaintWindow(LayoutDeviceIntRegion aRegion) {
+  nsCOMPtr<nsIWidget> widget = GetWidgetForListenerEvents();
+
+  nsIWidgetListener* listener = widget->GetWidgetListener();
+  if (!listener) return false;
+
+  bool returnValue = false;
+  bool oldDispatchPaint = mIsDispatchPaint;
+  mIsDispatchPaint = true;
+  returnValue = listener->PaintWindow(widget, aRegion);
+
+  listener = widget->GetWidgetListener();
+  if (listener) {
+    listener->DidPaintWindow();
+  }
+
+  mIsDispatchPaint = oldDispatchPaint;
+  return returnValue;
+}
+
+bool nsChildView::PaintWindowInDrawTarget(gfx::DrawTarget* aDT,
+                                          const LayoutDeviceIntRegion& aRegion,
+                                          const gfx::IntSize& aSurfaceSize) {
+  if (!aDT || !aDT->IsValid()) {
+    return false;
+  }
+  gfxContext targetContext(aDT);
+
+  // Set up the clip region and clear existing contents in the backing surface.
+  targetContext.NewPath();
+  for (auto iter = aRegion.RectIter(); !iter.Done(); iter.Next()) {
+    const LayoutDeviceIntRect& r = iter.Get();
+    targetContext.Rectangle(gfxRect(r.x, r.y, r.width, r.height));
+    aDT->ClearRect(gfx::Rect(r.ToUnknownRect()));
+  }
+  targetContext.Clip();
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(mView);
+  if (GetWindowRenderer()->GetBackendType() == LayersBackend::LAYERS_NONE) {
+    nsBaseWidget::AutoLayerManagerSetup setupLayerManager(
+        this, &targetContext, BufferMode::BUFFER_NONE);
+    return PaintWindow(aRegion);
+  }
+  return false;
+}
+
+void nsChildView::EnsureContentLayerForMainThreadPainting() {
+  // Ensure we have an mContentLayer of the correct size.
+  // The content layer gets created on demand for BasicLayers windows. We do
+  // not create it during widget creation because, for non-BasicLayers windows,
+  // the compositing layer manager will create any layers it needs.
+  gfx::IntSize size = GetBounds().Size().ToUnknownSize();
+  if (mContentLayer && mContentLayer->GetSize() != size) {
+    mNativeLayerRoot->RemoveLayer(mContentLayer);
+    mContentLayer = nullptr;
+  }
+  if (!mContentLayer) {
+    mPoolHandle = SurfacePool::Create(0)->GetHandleForGL(nullptr);
+    RefPtr<NativeLayer> contentLayer =
+        mNativeLayerRoot->CreateLayer(size, false, mPoolHandle);
+    mNativeLayerRoot->AppendLayer(contentLayer);
+    mContentLayer = contentLayer->AsNativeLayerCA();
+    mContentLayer->SetSurfaceIsFlipped(false);
+    mContentLayerInvalidRegion = GetBounds();
+  }
+}
+
+void nsChildView::PaintWindowInContentLayer() {
+  EnsureContentLayerForMainThreadPainting();
+  mPoolHandle->OnBeginFrame();
+  RefPtr<DrawTarget> dt = mContentLayer->NextSurfaceAsDrawTarget(
+      gfx::IntRect({}, mContentLayer->GetSize()),
+      mContentLayerInvalidRegion.ToUnknownRegion(), gfx::BackendType::SKIA);
+  if (!dt) {
+    return;
+  }
+
+  PaintWindowInDrawTarget(dt, mContentLayerInvalidRegion, dt->GetSize());
+  mContentLayer->NotifySurfaceReady();
+  mContentLayerInvalidRegion.SetEmpty();
+  mPoolHandle->OnEndFrame();
+}
+
+void nsChildView::HandleMainThreadCATransaction() {
+  WillPaintWindow();
+
+  if (GetWindowRenderer()->GetBackendType() == LayersBackend::LAYERS_NONE) {
+    // We're in BasicLayers mode, i.e. main thread software compositing.
+    // Composite the window into our layer's surface.
+    PaintWindowInContentLayer();
+  } else {
+    // Trigger a synchronous OMTC composite. This will call NextSurface and
+    // NotifySurfaceReady on the compositor thread to update mNativeLayerRoot's
+    // contents, and the main thread (this thread) will wait inside PaintWindow
+    // during that time.
+    PaintWindow(LayoutDeviceIntRegion(GetBounds()));
+  }
+
+  {
+    // Apply the changes inside mNativeLayerRoot to the underlying CALayers. Now
+    // is a good time to call this because we know we're currently inside a main
+    // thread CATransaction, and the lock makes sure that no composition is
+    // currently in progress, so we won't present half-composited state to the
+    // screen.
+    MutexAutoLock lock(mCompositingLock);
+    mNativeLayerRoot->CommitToScreen();
+  }
+
+  MaybeScheduleUnsuspendAsyncCATransactions();
+}
+
+#pragma mark -
+
+void nsChildView::ReportMoveEvent() { NotifyWindowMoved(mBounds.x, mBounds.y); }
+
+void nsChildView::ReportSizeEvent() {
+  if (mWidgetListener)
+    mWidgetListener->WindowResized(this, mBounds.width, mBounds.height);
+}
+
+#pragma mark -
+
+LayoutDeviceIntPoint nsChildView::GetClientOffset() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSPoint origin = [mView convertPoint:NSMakePoint(0, 0) toView:nil];
+  origin.y = [[mView window] frame].size.height - origin.y;
+  return CocoaPointsToDevPixels(origin);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(LayoutDeviceIntPoint(0, 0));
+}
+
+//    Return the offset between this child view and the screen.
+//    @return       -- widget origin in device-pixel coords
+LayoutDeviceIntPoint nsChildView::WidgetToScreenOffset() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSPoint origin = NSMakePoint(0, 0);
+
+  // 1. First translate view origin point into window coords.
+  // The returned point is in bottom-left coordinates.
+  origin = [mView convertPoint:origin toView:nil];
+
+  // 2. We turn the window-coord rect's origin into screen (still bottom-left)
+  // coords.
+  origin = nsCocoaUtils::ConvertPointToScreen([mView window], origin);
+
+  // 3. Since we're dealing in bottom-left coords, we need to make it top-left
+  // coords
+  //    before we pass it back to Gecko.
+  FlipCocoaScreenCoordinate(origin);
+
+  // convert to device pixels
+  return CocoaPointsToDevPixels(origin);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(LayoutDeviceIntPoint(0, 0));
+}
+
+nsresult nsChildView::SetTitle(const nsAString& title) {
+  // child views don't have titles
+  return NS_OK;
+}
+
+nsresult nsChildView::GetAttention(int32_t aCycleCount) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  [NSApp requestUserAttention:NSInformationalRequest];
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+/* static */
+bool nsChildView::DoHasPendingInputEvent() {
+  return sLastInputEventCount != GetCurrentInputEventCount();
+}
+
+/* static */
+uint32_t nsChildView::GetCurrentInputEventCount() {
+  // Can't use kCGAnyInputEventType because that updates too rarely for us (and
+  // always in increments of 30+!) and because apparently it's sort of broken
+  // on Tiger.  So just go ahead and query the counters we care about.
+  static const CGEventType eventTypes[] = {kCGEventLeftMouseDown,
+                                           kCGEventLeftMouseUp,
+                                           kCGEventRightMouseDown,
+                                           kCGEventRightMouseUp,
+                                           kCGEventMouseMoved,
+                                           kCGEventLeftMouseDragged,
+                                           kCGEventRightMouseDragged,
+                                           kCGEventKeyDown,
+                                           kCGEventKeyUp,
+                                           kCGEventScrollWheel,
+                                           kCGEventTabletPointer,
+                                           kCGEventOtherMouseDown,
+                                           kCGEventOtherMouseUp,
+                                           kCGEventOtherMouseDragged};
+
+  uint32_t eventCount = 0;
+  for (uint32_t i = 0; i < ArrayLength(eventTypes); ++i) {
+    eventCount += CGEventSourceCounterForEventType(
+        kCGEventSourceStateCombinedSessionState, eventTypes[i]);
+  }
+  return eventCount;
+}
+
+/* static */
+void nsChildView::UpdateCurrentInputEventCount() {
+  sLastInputEventCount = GetCurrentInputEventCount();
+}
+
+bool nsChildView::HasPendingInputEvent() { return DoHasPendingInputEvent(); }
+
+#pragma mark -
+
+void nsChildView::SetInputContext(const InputContext& aContext,
+                                  const InputContextAction& aAction) {
+  NS_ENSURE_TRUE_VOID(mTextInputHandler);
+
+  if (mTextInputHandler->IsFocused()) {
+    if (aContext.IsPasswordEditor()) {
+      TextInputHandler::EnableSecureEventInput();
+    } else {
+      TextInputHandler::EnsureSecureEventInputDisabled();
+    }
+  }
+
+  // IMEInputHandler::IsEditableContent() returns false when both
+  // IsASCIICableOnly() and IsIMEEnabled() return false.  So, be careful
+  // when you change the following code.  You might need to change
+  // IMEInputHandler::IsEditableContent() too.
+  mInputContext = aContext;
+  switch (aContext.mIMEState.mEnabled) {
+    case IMEEnabled::Enabled:
+      mTextInputHandler->SetASCIICapableOnly(false);
+      mTextInputHandler->EnableIME(true);
+      if (mInputContext.mIMEState.mOpen != IMEState::DONT_CHANGE_OPEN_STATE) {
+        mTextInputHandler->SetIMEOpenState(mInputContext.mIMEState.mOpen ==
+                                           IMEState::OPEN);
+      }
+      break;
+    case IMEEnabled::Disabled:
+      mTextInputHandler->SetASCIICapableOnly(false);
+      mTextInputHandler->EnableIME(false);
+      break;
+    case IMEEnabled::Password:
+      mTextInputHandler->SetASCIICapableOnly(true);
+      mTextInputHandler->EnableIME(false);
+      break;
+    default:
+      NS_ERROR("not implemented!");
+  }
+}
+
+InputContext nsChildView::GetInputContext() {
+  switch (mInputContext.mIMEState.mEnabled) {
+    case IMEEnabled::Enabled:
+      if (mTextInputHandler) {
+        mInputContext.mIMEState.mOpen = mTextInputHandler->IsIMEOpened()
+                                            ? IMEState::OPEN
+                                            : IMEState::CLOSED;
+        break;
+      }
+      // If mTextInputHandler is null, set CLOSED instead...
+      [[fallthrough]];
+    default:
+      mInputContext.mIMEState.mOpen = IMEState::CLOSED;
+      break;
+  }
+  return mInputContext;
+}
+
+TextEventDispatcherListener*
+nsChildView::GetNativeTextEventDispatcherListener() {
+  if (NS_WARN_IF(!mTextInputHandler)) {
+    return nullptr;
+  }
+  return mTextInputHandler;
+}
+
+nsresult nsChildView::AttachNativeKeyEvent(
+    mozilla::WidgetKeyboardEvent& aEvent) {
+  NS_ENSURE_TRUE(mTextInputHandler, NS_ERROR_NOT_AVAILABLE);
+  return mTextInputHandler->AttachNativeKeyEvent(aEvent);
+}
+
+bool nsChildView::GetEditCommands(NativeKeyBindingsType aType,
+                                  const WidgetKeyboardEvent& aEvent,
+                                  nsTArray<CommandInt>& aCommands) {
+  // Validate the arguments.
+  if (NS_WARN_IF(!nsIWidget::GetEditCommands(aType, aEvent, aCommands))) {
+    return false;
+  }
+
+  Maybe<WritingMode> writingMode;
+  if (aEvent.NeedsToRemapNavigationKey()) {
+    if (RefPtr<TextEventDispatcher> dispatcher = GetTextEventDispatcher()) {
+      writingMode = dispatcher->MaybeQueryWritingModeAtSelection();
+    }
+  }
+
+  NativeKeyBindings* keyBindings = NativeKeyBindings::GetInstance(aType);
+  keyBindings->GetEditCommands(aEvent, writingMode, aCommands);
+  return true;
+}
+
+NSView<mozView>* nsChildView::GetEditorView() {
+  NSView<mozView>* editorView = mView;
+  // We need to get editor's view. E.g., when the focus is in the bookmark
+  // dialog, the view is <panel> element of the dialog.  At this time, the key
+  // events are processed the parent window's view that has native focus.
+  WidgetQueryContentEvent queryContentState(true, eQueryContentState, this);
+  // This may be called during creating a menu popup frame due to creating
+  // widget synchronously and that causes Cocoa asking current window level.
+  // In this case, it's not safe to flush layout on the document and we don't
+  // need any layout information right now.
+  queryContentState.mNeedsToFlushLayout = false;
+  DispatchWindowEvent(queryContentState);
+  if (queryContentState.Succeeded() &&
+      queryContentState.mReply->mFocusedWidget) {
+    NSView<mozView>* view = static_cast<NSView<mozView>*>(
+        queryContentState.mReply->mFocusedWidget->GetNativeData(
+            NS_NATIVE_WIDGET));
+    if (view) editorView = view;
+  }
+  return editorView;
+}
+
+#pragma mark -
+
+void nsChildView::CreateCompositor() {
+  nsBaseWidget::CreateCompositor();
+  if (mCompositorBridgeChild) {
+    [mView setUsingOMTCompositor:true];
+  }
+}
+
+void nsChildView::ConfigureAPZCTreeManager() {
+  nsBaseWidget::ConfigureAPZCTreeManager();
+}
+
+void nsChildView::ConfigureAPZControllerThread() {
+  nsBaseWidget::ConfigureAPZControllerThread();
+}
+
+bool nsChildView::PreRender(WidgetRenderingContext* aContext)
+    MOZ_NO_THREAD_SAFETY_ANALYSIS {
+  // The lock makes sure that we don't attempt to tear down the view while
+  // compositing. That would make us unable to call postRender on it when the
+  // composition is done, thus keeping the GL context locked forever.
+  mCompositingLock.Lock();
+
+  if (aContext->mGL && gfxPlatform::CanMigrateMacGPUs()) {
+    GLContextCGL::Cast(aContext->mGL)->MigrateToActiveGPU();
+  }
+
+  return true;
+}
+
+void nsChildView::PostRender(WidgetRenderingContext* aContext)
+    MOZ_NO_THREAD_SAFETY_ANALYSIS {
+  mCompositingLock.Unlock();
+}
+
+RefPtr<layers::NativeLayerRoot> nsChildView::GetNativeLayerRoot() {
+  return mNativeLayerRoot;
+}
+
+static int32_t FindTitlebarBottom(
+    const nsTArray<nsIWidget::ThemeGeometry>& aThemeGeometries,
+    int32_t aWindowWidth) {
+  int32_t titlebarBottom = 0;
+  for (auto& g : aThemeGeometries) {
+    if (g.mType == eThemeGeometryTypeTitlebar && g.mRect.X() <= 0 &&
+        g.mRect.XMost() >= aWindowWidth && g.mRect.Y() <= 0) {
+      titlebarBottom = std::max(titlebarBottom, g.mRect.YMost());
+    }
+  }
+  return titlebarBottom;
+}
+
+static int32_t FindUnifiedToolbarBottom(
+    const nsTArray<nsIWidget::ThemeGeometry>& aThemeGeometries,
+    int32_t aWindowWidth, int32_t aTitlebarBottom) {
+  int32_t unifiedToolbarBottom = aTitlebarBottom;
+  for (uint32_t i = 0; i < aThemeGeometries.Length(); ++i) {
+    const nsIWidget::ThemeGeometry& g = aThemeGeometries[i];
+    if ((g.mType == eThemeGeometryTypeToolbar) && g.mRect.X() <= 0 &&
+        g.mRect.XMost() >= aWindowWidth && g.mRect.Y() <= aTitlebarBottom) {
+      unifiedToolbarBottom = std::max(unifiedToolbarBottom, g.mRect.YMost());
+    }
+  }
+  return unifiedToolbarBottom;
+}
+
+static LayoutDeviceIntRect FindFirstRectOfType(
+    const nsTArray<nsIWidget::ThemeGeometry>& aThemeGeometries,
+    nsITheme::ThemeGeometryType aThemeGeometryType) {
+  for (uint32_t i = 0; i < aThemeGeometries.Length(); ++i) {
+    const nsIWidget::ThemeGeometry& g = aThemeGeometries[i];
+    if (g.mType == aThemeGeometryType) {
+      return g.mRect;
+    }
+  }
+  return LayoutDeviceIntRect();
+}
+
+void nsChildView::UpdateThemeGeometries(
+    const nsTArray<ThemeGeometry>& aThemeGeometries) {
+  if (![mView window]) return;
+
+  UpdateVibrancy(aThemeGeometries);
+
+  if (![[mView window] isKindOfClass:[ToolbarWindow class]]) return;
+
+  // Update unified toolbar height and sheet attachment position.
+  int32_t windowWidth = mBounds.width;
+  int32_t titlebarBottom = FindTitlebarBottom(aThemeGeometries, windowWidth);
+  int32_t unifiedToolbarBottom =
+      FindUnifiedToolbarBottom(aThemeGeometries, windowWidth, titlebarBottom);
+  int32_t toolboxBottom =
+      FindFirstRectOfType(aThemeGeometries, eThemeGeometryTypeToolbox).YMost();
+
+  ToolbarWindow* win = (ToolbarWindow*)[mView window];
+  int32_t titlebarHeight = [win drawsContentsIntoWindowFrame]
+                               ? 0
+                               : CocoaPointsToDevPixels([win titlebarHeight]);
+  int32_t devUnifiedHeight = titlebarHeight + unifiedToolbarBottom;
+  [win setUnifiedToolbarHeight:DevPixelsToCocoaPoints(devUnifiedHeight)];
+
+  int32_t sheetPositionDevPx = std::max(toolboxBottom, unifiedToolbarBottom);
+  NSPoint sheetPositionView = {0, DevPixelsToCocoaPoints(sheetPositionDevPx)};
+  NSPoint sheetPositionWindow = [mView convertPoint:sheetPositionView
+                                             toView:nil];
+  [win setSheetAttachmentPosition:sheetPositionWindow.y];
+
+  // Update titlebar control offsets.
+  LayoutDeviceIntRect windowButtonRect =
+      FindFirstRectOfType(aThemeGeometries, eThemeGeometryTypeWindowButtons);
+  [win placeWindowButtons:[mView convertRect:DevPixelsToCocoaPoints(
+                                                 windowButtonRect)
+                                      toView:nil]];
+}
+
+static Maybe<VibrancyType> ThemeGeometryTypeToVibrancyType(
+    nsITheme::ThemeGeometryType aThemeGeometryType) {
+  switch (aThemeGeometryType) {
+    case eThemeGeometryTypeTooltip:
+      return Some(VibrancyType::TOOLTIP);
+    case eThemeGeometryTypeMenu:
+      return Some(VibrancyType::MENU);
+    default:
+      return Nothing();
+  }
+}
+
+static LayoutDeviceIntRegion GatherVibrantRegion(
+    const nsTArray<nsIWidget::ThemeGeometry>& aThemeGeometries,
+    VibrancyType aVibrancyType) {
+  LayoutDeviceIntRegion region;
+  for (auto& geometry : aThemeGeometries) {
+    if (ThemeGeometryTypeToVibrancyType(geometry.mType) ==
+        Some(aVibrancyType)) {
+      region.OrWith(geometry.mRect);
+    }
+  }
+  return region;
+}
+
+template <typename Region>
+static void MakeRegionsNonOverlappingImpl(Region& aOutUnion) {}
+
+template <typename Region, typename... Regions>
+static void MakeRegionsNonOverlappingImpl(Region& aOutUnion, Region& aFirst,
+                                          Regions&... aRest) {
+  MakeRegionsNonOverlappingImpl(aOutUnion, aRest...);
+  aFirst.SubOut(aOutUnion);
+  aOutUnion.OrWith(aFirst);
+}
+
+// Subtracts parts from regions in such a way that they don't have any overlap.
+// Each region in the argument list will have the union of all the regions
+// *following* it subtracted from itself. In other words, the arguments are
+// sorted low priority to high priority.
+template <typename Region, typename... Regions>
+static void MakeRegionsNonOverlapping(Region& aFirst, Regions&... aRest) {
+  Region unionOfAll;
+  MakeRegionsNonOverlappingImpl(unionOfAll, aFirst, aRest...);
+}
+
+void nsChildView::UpdateVibrancy(
+    const nsTArray<ThemeGeometry>& aThemeGeometries) {
+  LayoutDeviceIntRegion menuRegion =
+      GatherVibrantRegion(aThemeGeometries, VibrancyType::MENU);
+  LayoutDeviceIntRegion tooltipRegion =
+      GatherVibrantRegion(aThemeGeometries, VibrancyType::TOOLTIP);
+
+  MakeRegionsNonOverlapping(menuRegion, tooltipRegion);
+
+  auto& vm = EnsureVibrancyManager();
+  bool changed = false;
+  changed |= vm.UpdateVibrantRegion(VibrancyType::MENU, menuRegion);
+  changed |= vm.UpdateVibrantRegion(VibrancyType::TOOLTIP, tooltipRegion);
+
+  if (changed) {
+    SuspendAsyncCATransactions();
+  }
+}
+
+mozilla::VibrancyManager& nsChildView::EnsureVibrancyManager() {
+  MOZ_ASSERT(mView, "Only call this once we have a view!");
+  if (!mVibrancyManager) {
+    mVibrancyManager =
+        MakeUnique<VibrancyManager>(*this, [mView vibrancyViewsContainer]);
+  }
+  return *mVibrancyManager;
+}
+
+void nsChildView::UpdateBoundsFromView() {
+  auto oldSize = mBounds.Size();
+  mBounds = CocoaPointsToDevPixels([mView frame]);
+  if (mBounds.Size() != oldSize) {
+    SuspendAsyncCATransactions();
+  }
+}
+
+@interface NonDraggableView : NSView
+@end
+
+@implementation NonDraggableView
+- (BOOL)mouseDownCanMoveWindow {
+  return NO;
+}
+- (NSView*)hitTest:(NSPoint)aPoint {
+  return nil;
+}
+- (NSRect)_opaqueRectForWindowMoveWhenInTitlebar {
+  // In NSWindows that use NSWindowStyleMaskFullSizeContentView, NSViews which
+  // overlap the titlebar do not disable window dragging in the overlapping
+  // areas even if they return NO from mouseDownCanMoveWindow. This can have
+  // unfortunate effects: For example, dragging tabs in a browser window would
+  // move the window if those tabs are in the titlebar.
+  // macOS does not seem to offer a documented way to opt-out of the forced
+  // window dragging in the titlebar.
+  // Overriding _opaqueRectForWindowMoveWhenInTitlebar is an undocumented way
+  // of opting out of this behavior. This method was added in 10.11 and is used
+  // by some NSControl subclasses to prevent window dragging in the titlebar.
+  // The function which assembles the draggable area of the window calls
+  // _opaqueRect for the content area and _opaqueRectForWindowMoveWhenInTitlebar
+  // for the titlebar area, on all visible NSViews. The default implementation
+  // of _opaqueRect returns [self visibleRect], and the default implementation
+  // of _opaqueRectForWindowMoveWhenInTitlebar returns NSZeroRect unless it's
+  // overridden.
+  //
+  // Since this view is constructed and used such that its entire bounds is the
+  // relevant region, we just return our bounds.
+  return self.bounds;
+}
+@end
+
+void nsChildView::UpdateWindowDraggingRegion(
+    const LayoutDeviceIntRegion& aRegion) {
+  // mView returns YES from mouseDownCanMoveWindow, so we need to put NSViews
+  // that return NO from mouseDownCanMoveWindow in the places that shouldn't
+  // be draggable. We can't do it the other way round because returning
+  // YES from mouseDownCanMoveWindow doesn't have any effect if there's a
+  // superview that returns NO.
+  LayoutDeviceIntRegion nonDraggable;
+  nonDraggable.Sub(LayoutDeviceIntRect(0, 0, mBounds.width, mBounds.height),
+                   aRegion);
+
+  __block bool changed = false;
+
+  // Suppress calls to setNeedsDisplay during NSView geometry changes.
+  ManipulateViewWithoutNeedingDisplay(mView, ^() {
+    changed = mNonDraggableRegion.UpdateRegion(
+        nonDraggable, *this, [mView nonDraggableViewsContainer], ^() {
+          return [[NonDraggableView alloc] initWithFrame:NSZeroRect];
+        });
+  });
+
+  if (changed) {
+    // Trigger an update to the window server. This will call
+    // mouseDownCanMoveWindow.
+    // Doing this manually is only necessary because we're suppressing
+    // setNeedsDisplay calls above.
+    [[mView window] setMovableByWindowBackground:NO];
+    [[mView window] setMovableByWindowBackground:YES];
+  }
+}
+
+nsEventStatus nsChildView::DispatchAPZInputEvent(InputData& aEvent) {
+  APZEventResult result;
+
+  if (mAPZC) {
+    result = mAPZC->InputBridge()->ReceiveInputEvent(aEvent);
+  }
+
+  if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+    return result.GetStatus();
+  }
+
+  if (aEvent.mInputType == PINCHGESTURE_INPUT) {
+    PinchGestureInput& pinchEvent = aEvent.AsPinchGestureInput();
+    WidgetWheelEvent wheelEvent = pinchEvent.ToWidgetEvent(this);
+    ProcessUntransformedAPZEvent(&wheelEvent, result);
+  } else if (aEvent.mInputType == TAPGESTURE_INPUT) {
+    TapGestureInput& tapEvent = aEvent.AsTapGestureInput();
+    WidgetSimpleGestureEvent gestureEvent = tapEvent.ToWidgetEvent(this);
+    ProcessUntransformedAPZEvent(&gestureEvent, result);
+  } else {
+    MOZ_ASSERT_UNREACHABLE();
+  }
+
+  return result.GetStatus();
+}
+
+void nsChildView::DispatchAPZWheelInputEvent(InputData& aEvent) {
+  if (mSwipeTracker && aEvent.mInputType == PANGESTURE_INPUT) {
+    // Give the swipe tracker a first pass at the event. If a new pan gesture
+    // has been started since the beginning of the swipe, the swipe tracker
+    // will know to ignore the event.
+    nsEventStatus status =
+        mSwipeTracker->ProcessEvent(aEvent.AsPanGestureInput());
+    if (status == nsEventStatus_eConsumeNoDefault) {
+      return;
+    }
+  }
+
+  WidgetWheelEvent event(true, eWheel, this);
+
+  if (mAPZC) {
+    APZEventResult result;
+
+    switch (aEvent.mInputType) {
+      case PANGESTURE_INPUT: {
+        result = mAPZC->InputBridge()->ReceiveInputEvent(aEvent);
+        if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+          return;
+        }
+
+        event = MayStartSwipeForAPZ(aEvent.AsPanGestureInput(), result);
+        break;
+      }
+      case SCROLLWHEEL_INPUT: {
+        // For wheel events on OS X, send it to APZ using the WidgetInputEvent
+        // variant of ReceiveInputEvent, because the APZInputBridge version of
+        // that function has special handling (for delta multipliers etc.) that
+        // we need to run. Using the InputData variant would bypass that and
+        // go straight to the APZCTreeManager subclass.
+        event = aEvent.AsScrollWheelInput().ToWidgetEvent(this);
+        result = mAPZC->InputBridge()->ReceiveInputEvent(event);
+        if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+          return;
+        }
+        break;
+      };
+      default:
+        MOZ_CRASH("unsupported event type");
+        return;
+    }
+    if (event.mMessage == eWheel &&
+        (event.mDeltaX != 0 || event.mDeltaY != 0)) {
+      ProcessUntransformedAPZEvent(&event, result);
+    }
+    return;
+  }
+
+  nsEventStatus status;
+  switch (aEvent.mInputType) {
+    case PANGESTURE_INPUT: {
+      if (MayStartSwipeForNonAPZ(aEvent.AsPanGestureInput())) {
+        return;
+      }
+      event = aEvent.AsPanGestureInput().ToWidgetEvent(this);
+      break;
+    }
+    case SCROLLWHEEL_INPUT: {
+      event = aEvent.AsScrollWheelInput().ToWidgetEvent(this);
+      break;
+    }
+    default:
+      MOZ_CRASH("unexpected event type");
+      return;
+  }
+  if (event.mMessage == eWheel && (event.mDeltaX != 0 || event.mDeltaY != 0)) {
+    DispatchEvent(&event, status);
+  }
+}
+
+void nsChildView::DispatchDoubleTapGesture(TimeStamp aEventTimeStamp,
+                                           LayoutDeviceIntPoint aScreenPosition,
+                                           mozilla::Modifiers aModifiers) {
+  if (StaticPrefs::apz_mac_enable_double_tap_zoom_touchpad_gesture()) {
+    TapGestureInput event{
+        TapGestureInput::TAPGESTURE_DOUBLE, aEventTimeStamp,
+        ViewAs<ScreenPixel>(
+            aScreenPosition,
+            PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent),
+        aModifiers};
+
+    DispatchAPZInputEvent(event);
+  } else {
+    // Setup the "double tap" event.
+    WidgetSimpleGestureEvent geckoEvent(true, eTapGesture, this);
+    // do what convertCocoaMouseEvent does basically.
+    geckoEvent.mRefPoint = aScreenPosition;
+    geckoEvent.mModifiers = aModifiers;
+    geckoEvent.mTimeStamp = aEventTimeStamp;
+    geckoEvent.mClickCount = 1;
+
+    // Send the event.
+    DispatchWindowEvent(geckoEvent);
+  }
+}
+
+void nsChildView::LookUpDictionary(
+    const nsAString& aText, const nsTArray<mozilla::FontRange>& aFontRangeArray,
+    const bool aIsVertical, const LayoutDeviceIntPoint& aPoint) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NSMutableAttributedString* attrStr =
+      nsCocoaUtils::GetNSMutableAttributedString(
+          aText, aFontRangeArray, aIsVertical, BackingScaleFactor());
+  NSPoint pt =
+      nsCocoaUtils::DevPixelsToCocoaPoints(aPoint, BackingScaleFactor());
+  NSDictionary* attributes = [attrStr attributesAtIndex:0 effectiveRange:nil];
+  NSFont* font = [attributes objectForKey:NSFontAttributeName];
+  if (font) {
+    if (aIsVertical) {
+      pt.x -= [font descender];
+    } else {
+      pt.y += [font ascender];
+    }
+  }
+
+  [mView showDefinitionForAttributedString:attrStr atPoint:pt];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+#ifdef ACCESSIBILITY
+already_AddRefed<a11y::LocalAccessible> nsChildView::GetDocumentAccessible() {
+  if (!mozilla::a11y::ShouldA11yBeEnabled()) return nullptr;
+
+  // mAccessible might be dead if accessibility was previously disabled and is
+  // now being enabled again.
+  if (mAccessible && mAccessible->IsAlive()) {
+    RefPtr<a11y::LocalAccessible> ret;
+    CallQueryReferent(mAccessible.get(), static_cast<a11y::LocalAccessible**>(
+                                             getter_AddRefs(ret)));
+    return ret.forget();
+  }
+
+  // need to fetch the accessible anew, because it has gone away.
+  // cache the accessible in our weak ptr
+  RefPtr<a11y::LocalAccessible> acc = GetRootAccessible();
+  mAccessible = do_GetWeakReference(acc.get());
+
+  return acc.forget();
+}
+#endif
+
+class WidgetsReleaserRunnable final : public mozilla::Runnable {
+ public:
+  explicit WidgetsReleaserRunnable(nsTArray<nsCOMPtr<nsIWidget>>&& aWidgetArray)
+      : mozilla::Runnable("WidgetsReleaserRunnable"),
+        mWidgetArray(std::move(aWidgetArray)) {}
+
+  // Do nothing; all this runnable does is hold a reference the widgets in
+  // mWidgetArray, and those references will be dropped when this runnable
+  // is destroyed.
+
+ private:
+  nsTArray<nsCOMPtr<nsIWidget>> mWidgetArray;
+};
+
+#pragma mark -
+
+// ViewRegionContainerView is a view class for certain subviews of ChildView
+// which contain the NSViews created for ViewRegions (see ViewRegion.h).
+// It doesn't do anything interesting, it only acts as a container so that it's
+// easier for ChildView to control the z order of its children.
+@interface ViewRegionContainerView : NSView {
+}
+@end
+
+@implementation ViewRegionContainerView
+
+- (NSView*)hitTest:(NSPoint)aPoint {
+  return nil;  // Be transparent to mouse events.
+}
+
+- (BOOL)isFlipped {
+  return [[self superview] isFlipped];
+}
+
+- (BOOL)mouseDownCanMoveWindow {
+  return [[self superview] mouseDownCanMoveWindow];
+}
+
+@end
+
+@implementation ChildView
+
+// globalDragPboard is non-null during native drag sessions that did not
+// originate in our native NSView (it is set in |draggingEntered:|). It is unset
+// when the drag session ends for this view, either with the mouse exiting or
+// when a drop occurs in this view.
+NSPasteboard* globalDragPboard = nil;
+
+// gLastDragView and gLastDragMouseDownEvent are used to communicate information
+// to the drag service during drag invocation (starting a drag in from the
+// view). gLastDragView is only non-null while a mouse button is pressed, so
+// between mouseDown and mouseUp.
+NSView* gLastDragView = nil;             // [weak]
+NSEvent* gLastDragMouseDownEvent = nil;  // [strong]
+
++ (void)initialize {
+  static BOOL initialized = NO;
+
+  if (!initialized) {
+    // Inform the OS about the types of services (from the "Services" menu)
+    // that we can handle.
+    NSArray* types = @[
+      [UTIHelper stringFromPboardType:NSPasteboardTypeString],
+      [UTIHelper stringFromPboardType:NSPasteboardTypeHTML]
+    ];
+    [NSApp registerServicesMenuSendTypes:types returnTypes:types];
+    initialized = YES;
+  }
+}
+
++ (void)registerViewForDraggedTypes:(NSView*)aView {
+  [aView
+      registerForDraggedTypes:
+          [NSArray
+              arrayWithObjects:
+                  [UTIHelper stringFromPboardType:NSFilenamesPboardType],
+                  [UTIHelper stringFromPboardType:kMozFileUrlsPboardType],
+                  [UTIHelper stringFromPboardType:NSPasteboardTypeString],
+                  [UTIHelper stringFromPboardType:NSPasteboardTypeHTML],
+                  [UTIHelper
+                      stringFromPboardType:(NSString*)
+                                               kPasteboardTypeFileURLPromise],
+                  [UTIHelper stringFromPboardType:kMozWildcardPboardType],
+                  [UTIHelper stringFromPboardType:kPublicUrlPboardType],
+                  [UTIHelper stringFromPboardType:kPublicUrlNamePboardType],
+                  [UTIHelper stringFromPboardType:kUrlsWithTitlesPboardType],
+                  nil]];
+}
+
+// initWithFrame:geckoChild:
+- (id)initWithFrame:(NSRect)inFrame geckoChild:(nsChildView*)inChild {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if ((self = [super initWithFrame:inFrame])) {
+    mGeckoChild = inChild;
+    mBlockedLastMouseDown = NO;
+    mExpectingWheelStop = NO;
+
+    mLastMouseDownEvent = nil;
+    mLastKeyDownEvent = nil;
+    mClickThroughMouseDownEvent = nil;
+    mDragService = nullptr;
+
+    mGestureState = eGestureState_None;
+    mCumulativeRotation = 0.0;
+
+    mIsUpdatingLayer = NO;
+
+    [self setFocusRingType:NSFocusRingTypeNone];
+
+#ifdef __LP64__
+    mCancelSwipeAnimation = nil;
+#endif
+
+    mNonDraggableViewsContainer =
+        [[ViewRegionContainerView alloc] initWithFrame:[self bounds]];
+    mVibrancyViewsContainer =
+        [[ViewRegionContainerView alloc] initWithFrame:[self bounds]];
+
+    [mNonDraggableViewsContainer
+        setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
+    [mVibrancyViewsContainer
+        setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
+
+    [self addSubview:mNonDraggableViewsContainer];
+    [self addSubview:mVibrancyViewsContainer];
+
+    mPixelHostingView = [[PixelHostingView alloc] initWithFrame:[self bounds]];
+    [mPixelHostingView
+        setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
+
+    [self addSubview:mPixelHostingView];
+
+    mRootCALayer = [[CALayer layer] retain];
+    mRootCALayer.position = NSZeroPoint;
+    mRootCALayer.bounds = NSZeroRect;
+    mRootCALayer.anchorPoint = NSZeroPoint;
+    mRootCALayer.contentsGravity = kCAGravityTopLeft;
+    [[mPixelHostingView layer] addSublayer:mRootCALayer];
+
+    mLastPressureStage = 0;
+  }
+
+  // register for things we'll take from other applications
+  [ChildView registerViewForDraggedTypes:self];
+
+  return self;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (NSTextInputContext*)inputContext {
+  if (!mGeckoChild) {
+    // -[ChildView widgetDestroyed] has been called, but
+    // -[ChildView delayedTearDown] has not yet completed.  Accessing
+    // [super inputContext] now would uselessly recreate a text input context
+    // for us, under which -[ChildView validAttributesForMarkedText] would
+    // be called and the assertion checking for mTextInputHandler would fail.
+    // We return nil to avoid that.
+    return nil;
+  }
+  return [super inputContext];
+}
+
+- (void)installTextInputHandler:(TextInputHandler*)aHandler {
+  mTextInputHandler = aHandler;
+}
+
+- (void)uninstallTextInputHandler {
+  mTextInputHandler = nullptr;
+}
+
+- (NSView*)vibrancyViewsContainer {
+  return mVibrancyViewsContainer;
+}
+
+- (NSView*)nonDraggableViewsContainer {
+  return mNonDraggableViewsContainer;
+}
+
+- (NSView*)pixelHostingView {
+  return mPixelHostingView;
+}
+
+- (void)dealloc {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [mLastMouseDownEvent release];
+  [mLastKeyDownEvent release];
+  [mClickThroughMouseDownEvent release];
+  ChildViewMouseTracker::OnDestroyView(self);
+
+  [mVibrancyViewsContainer removeFromSuperview];
+  [mVibrancyViewsContainer release];
+  [mNonDraggableViewsContainer removeFromSuperview];
+  [mNonDraggableViewsContainer release];
+  [mPixelHostingView removeFromSuperview];
+  [mPixelHostingView release];
+  [mRootCALayer release];
+
+  if (gLastDragView == self) {
+    gLastDragView = nil;
+  }
+
+  [super dealloc];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)widgetDestroyed {
+  if (mTextInputHandler) {
+    mTextInputHandler->OnDestroyWidget(mGeckoChild);
+    mTextInputHandler = nullptr;
+  }
+  mGeckoChild = nullptr;
+
+  // Just in case we're destroyed abruptly and missed the draggingExited
+  // or performDragOperation message.
+  NS_IF_RELEASE(mDragService);
+}
+
+// mozView method, return our gecko child view widget. Note this does not
+// AddRef.
+- (nsIWidget*)widget {
+  return static_cast<nsIWidget*>(mGeckoChild);
+}
+
+- (NSString*)description {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return [NSString stringWithFormat:@"ChildView %p, gecko child %p, frame %@",
+                                    self, mGeckoChild,
+                                    NSStringFromRect([self frame])];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+// Make the origin of this view the topLeft corner (gecko origin) rather
+// than the bottomLeft corner (standard cocoa origin).
+- (BOOL)isFlipped {
+  return YES;
+}
+
+// We accept key and mouse events, so don't keep passing them up the chain.
+// Allow this to be a 'focused' widget for event dispatch.
+- (BOOL)acceptsFirstResponder {
+  return YES;
+}
+
+// Accept mouse down events on background windows
+- (BOOL)acceptsFirstMouse:(NSEvent*)aEvent {
+  if (![[self window] isKindOfClass:[PopupWindow class]]) {
+    // We rely on this function to tell us that the mousedown was on a
+    // background window. Inside mouseDown we can't tell whether we were
+    // inactive because at that point we've already been made active.
+    // Unfortunately, acceptsFirstMouse is called for PopupWindows even when
+    // their parent window is active, so ignore this on them for now.
+    mClickThroughMouseDownEvent = [aEvent retain];
+  }
+  return YES;
+}
+
+- (BOOL)mouseDownCanMoveWindow {
+  // Return YES so that parts of this view can be draggable. The non-draggable
+  // parts will be covered by NSViews that return NO from
+  // mouseDownCanMoveWindow and thus override draggability from the inside.
+  // These views are assembled in nsChildView::UpdateWindowDraggingRegion.
+  return YES;
+}
+
+- (void)viewDidChangeBackingProperties {
+  [super viewDidChangeBackingProperties];
+  if (mGeckoChild) {
+    // actually, it could be the color space that's changed,
+    // but we can't tell the difference here except by retrieving
+    // the backing scale factor and comparing to the old value
+    mGeckoChild->BackingScaleFactorChanged();
+  }
+}
+
+- (BOOL)isCoveringTitlebar {
+  return [[self window] isKindOfClass:[BaseWindow class]] &&
+         [(BaseWindow*)[self window] mainChildView] == self &&
+         [(BaseWindow*)[self window] drawsContentsIntoWindowFrame];
+}
+
+- (void)viewWillStartLiveResize {
+  nsCocoaWindow* windowWidget =
+      mGeckoChild ? mGeckoChild->GetAppWindowWidget() : nullptr;
+  if (windowWidget) {
+    windowWidget->NotifyLiveResizeStarted();
+  }
+}
+
+- (void)viewDidEndLiveResize {
+  // mGeckoChild may legitimately be null here. It should also have been null
+  // in viewWillStartLiveResize, so there's no problem. However if we run into
+  // cases where the windowWidget was non-null in viewWillStartLiveResize but
+  // is null here, that might be problematic because we might get stuck with
+  // a content process that has the displayport suppressed. If that scenario
+  // arises (I'm not sure that it does) we will need to handle it gracefully.
+  nsCocoaWindow* windowWidget =
+      mGeckoChild ? mGeckoChild->GetAppWindowWidget() : nullptr;
+  if (windowWidget) {
+    windowWidget->NotifyLiveResizeStopped();
+  }
+}
+
+- (void)markLayerForDisplay {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+  if (!mIsUpdatingLayer) {
+    // This call will cause updateRootCALayer to be called during the upcoming
+    // main thread CoreAnimation transaction. It will also trigger a transaction
+    // if no transaction is currently pending.
+    [[mPixelHostingView layer] setNeedsDisplay];
+  }
+}
+
+- (void)ensureNextCompositeIsAtomicWithMainThreadPaint {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+  if (mGeckoChild) {
+    mGeckoChild->SuspendAsyncCATransactions();
+  }
+}
+
+- (void)updateRootCALayer {
+  if (NS_IsMainThread() && mGeckoChild) {
+    MOZ_RELEASE_ASSERT(!mIsUpdatingLayer, "Re-entrant layer display?");
+    mIsUpdatingLayer = YES;
+    mGeckoChild->HandleMainThreadCATransaction();
+    mIsUpdatingLayer = NO;
+  }
+}
+
+- (CALayer*)rootCALayer {
+  return mRootCALayer;
+}
+
+// If we've just created a non-native context menu, we need to mark it as
+// such and let the OS (and other programs) know when it opens and closes
+// (this is how the OS knows to close other programs' context menus when
+// ours open).  We send the initial notification here, but others are sent
+// in nsCocoaWindow::Show().
+- (void)maybeInitContextMenuTracking {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mozilla::widget::NativeMenuSupport::ShouldUseNativeContextMenus()) {
+    return;
+  }
+
+  nsIRollupListener* rollupListener = nsBaseWidget::GetActiveRollupListener();
+  NS_ENSURE_TRUE_VOID(rollupListener);
+  nsCOMPtr<nsIWidget> widget = rollupListener->GetRollupWidget();
+  NS_ENSURE_TRUE_VOID(widget);
+
+  NSWindow* popupWindow = (NSWindow*)widget->GetNativeData(NS_NATIVE_WINDOW);
+  if (!popupWindow || ![popupWindow isKindOfClass:[PopupWindow class]]) return;
+
+  [[NSDistributedNotificationCenter defaultCenter]
+      postNotificationName:@"com.apple.HIToolbox.beginMenuTrackingNotification"
+                    object:@"org.mozilla.gecko.PopupWindow"];
+  [(PopupWindow*)popupWindow setIsContextMenu:YES];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Returns true if the event should no longer be processed, false otherwise.
+// This does not return whether or not anything was rolled up.
+- (BOOL)maybeRollup:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  BOOL consumeEvent = NO;
+
+  nsIRollupListener* rollupListener = nsBaseWidget::GetActiveRollupListener();
+  NS_ENSURE_TRUE(rollupListener, false);
+
+  BOOL isWheelTypeEvent = [theEvent type] == NSEventTypeScrollWheel ||
+                          [theEvent type] == NSEventTypeMagnify ||
+                          [theEvent type] == NSEventTypeSmartMagnify;
+
+  if (!isWheelTypeEvent && rollupListener->RollupNativeMenu()) {
+    // A native menu was rolled up.
+    // Don't consume this event; if the menu wanted to consume this event it
+    // would already have done so and we wouldn't even get here. For example, we
+    // won't get here for left clicks that close native menus (because the
+    // native menu consumes it), but we will get here for right clicks that
+    // close native menus, and we do not want to consume those right clicks.
+    return NO;
+  }
+
+  nsCOMPtr<nsIWidget> rollupWidget = rollupListener->GetRollupWidget();
+  if (!rollupWidget) {
+    return consumeEvent;
+  }
+
+  NSWindow* currentPopup =
+      static_cast<NSWindow*>(rollupWidget->GetNativeData(NS_NATIVE_WINDOW));
+  if (nsCocoaUtils::IsEventOverWindow(theEvent, currentPopup)) {
+    return consumeEvent;
+  }
+
+  // Check to see if scroll/zoom events should roll up the popup
+  if (isWheelTypeEvent) {
+    // consume scroll events that aren't over the popup unless the popup is an
+    // arrow panel.
+    consumeEvent = rollupListener->ShouldConsumeOnMouseWheelEvent();
+    if (!rollupListener->ShouldRollupOnMouseWheelEvent()) {
+      return consumeEvent;
+    }
+  }
+
+  // if we're dealing with menus, we probably have submenus and
+  // we don't want to rollup if the click is in a parent menu of
+  // the current submenu
+  uint32_t popupsToRollup = UINT32_MAX;
+  AutoTArray<nsIWidget*, 5> widgetChain;
+  uint32_t sameTypeCount = rollupListener->GetSubmenuWidgetChain(&widgetChain);
+  for (uint32_t i = 0; i < widgetChain.Length(); i++) {
+    nsIWidget* widget = widgetChain[i];
+    NSWindow* currWindow = (NSWindow*)widget->GetNativeData(NS_NATIVE_WINDOW);
+    if (nsCocoaUtils::IsEventOverWindow(theEvent, currWindow)) {
+      // don't roll up if the mouse event occurred within a menu of the
+      // same type. If the mouse event occurred in a menu higher than
+      // that, roll up, but pass the number of popups to Rollup so
+      // that only those of the same type close up.
+      if (i < sameTypeCount) {
+        return consumeEvent;
+      }
+      popupsToRollup = sameTypeCount;
+      break;
+    }
+  }
+
+  LayoutDeviceIntPoint devPoint;
+  nsIRollupListener::RollupOptions rollupOptions{
+      popupsToRollup, nsIRollupListener::FlushViews::Yes};
+  if ([theEvent type] == NSEventTypeLeftMouseDown) {
+    NSPoint point = [NSEvent mouseLocation];
+    FlipCocoaScreenCoordinate(point);
+    devPoint = mGeckoChild->CocoaPointsToDevPixels(point);
+    rollupOptions.mPoint = &devPoint;
+  }
+  consumeEvent = (BOOL)rollupListener->Rollup(rollupOptions);
+  return consumeEvent;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NO);
+}
+
+- (void)swipeWithEvent:(NSEvent*)anEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!anEvent || !mGeckoChild) {
+    return;
+  }
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  float deltaX = [anEvent deltaX];  // left=1.0, right=-1.0
+  float deltaY = [anEvent deltaY];  // up=1.0, down=-1.0
+
+  // Setup the "swipe" event.
+  WidgetSimpleGestureEvent geckoEvent(true, eSwipeGesture, mGeckoChild);
+  [self convertCocoaMouseEvent:anEvent toGeckoEvent:&geckoEvent];
+
+  // Record the left/right direction.
+  if (deltaX > 0.0)
+    geckoEvent.mDirection |= dom::SimpleGestureEvent_Binding::DIRECTION_LEFT;
+  else if (deltaX < 0.0)
+    geckoEvent.mDirection |= dom::SimpleGestureEvent_Binding::DIRECTION_RIGHT;
+
+  // Record the up/down direction.
+  if (deltaY > 0.0)
+    geckoEvent.mDirection |= dom::SimpleGestureEvent_Binding::DIRECTION_UP;
+  else if (deltaY < 0.0)
+    geckoEvent.mDirection |= dom::SimpleGestureEvent_Binding::DIRECTION_DOWN;
+
+  // Send the event.
+  mGeckoChild->DispatchWindowEvent(geckoEvent);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Pinch zoom gesture.
+- (void)magnifyWithEvent:(NSEvent*)anEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if ([self maybeRollup:anEvent]) {
+    return;
+  }
+
+  if (!mGeckoChild) {
+    return;
+  }
+
+  // Instead of calling beginOrEndGestureForEventPhase we basically inline
+  // the effects of it here, because that function doesn't play too well with
+  // how we create PinchGestureInput events below. The main point of that
+  // function is to avoid flip-flopping between rotation/magnify gestures, which
+  // we can do by checking and setting mGestureState appropriately. A secondary
+  // result of that function is to send the final eMagnifyGesture event when
+  // the gesture ends, but APZ takes care of that for us.
+  if (mGestureState == eGestureState_RotateGesture &&
+      [anEvent phase] != NSEventPhaseBegan) {
+    // If we're already in a rotation and not "starting" a magnify, abort.
+    return;
+  }
+  mGestureState = eGestureState_MagnifyGesture;
+
+  NSPoint locationInWindow =
+      nsCocoaUtils::EventLocationForWindow(anEvent, [self window]);
+  ScreenPoint position = ViewAs<ScreenPixel>(
+      [self convertWindowCoordinatesRoundDown:locationInWindow],
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+  ExternalPoint screenOffset = ViewAs<ExternalPixel>(
+      mGeckoChild->WidgetToScreenOffset(),
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+
+  TimeStamp eventTimeStamp =
+      nsCocoaUtils::GetEventTimeStamp([anEvent timestamp]);
+  NSEventPhase eventPhase = [anEvent phase];
+  PinchGestureInput::PinchGestureType pinchGestureType;
+
+  switch (eventPhase) {
+    case NSEventPhaseBegan: {
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_START;
+      break;
+    }
+    case NSEventPhaseChanged: {
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_SCALE;
+      break;
+    }
+    case NSEventPhaseEnded: {
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_END;
+      mGestureState = eGestureState_None;
+      break;
+    }
+    default: {
+      NS_WARNING("Unexpected phase for pinch gesture event.");
+      return;
+    }
+  }
+
+  PinchGestureInput event{pinchGestureType,
+                          PinchGestureInput::TRACKPAD,
+                          eventTimeStamp,
+                          screenOffset,
+                          position,
+                          100.0,
+                          100.0 * (1.0 - [anEvent magnification]),
+                          nsCocoaUtils::ModifiersForEvent(anEvent)};
+
+  mGeckoChild->DispatchAPZInputEvent(event);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Smart zoom gesture, i.e. two-finger double tap on trackpads.
+- (void)smartMagnifyWithEvent:(NSEvent*)anEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!anEvent || !mGeckoChild ||
+      [self beginOrEndGestureForEventPhase:anEvent]) {
+    return;
+  }
+
+  if ([self maybeRollup:anEvent]) {
+    return;
+  }
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  if (StaticPrefs::apz_mac_enable_double_tap_zoom_touchpad_gesture()) {
+    TimeStamp eventTimeStamp =
+        nsCocoaUtils::GetEventTimeStamp([anEvent timestamp]);
+    NSPoint locationInWindow =
+        nsCocoaUtils::EventLocationForWindow(anEvent, [self window]);
+    LayoutDevicePoint position =
+        [self convertWindowCoordinatesRoundDown:locationInWindow];
+
+    mGeckoChild->DispatchDoubleTapGesture(
+        eventTimeStamp, RoundedToInt(position),
+        nsCocoaUtils::ModifiersForEvent(anEvent));
+  } else {
+    // Setup the "double tap" event.
+    WidgetSimpleGestureEvent geckoEvent(true, eTapGesture, mGeckoChild);
+    [self convertCocoaMouseEvent:anEvent toGeckoEvent:&geckoEvent];
+    geckoEvent.mClickCount = 1;
+
+    // Send the event.
+    mGeckoChild->DispatchWindowEvent(geckoEvent);
+  }
+
+  // Clear the gesture state
+  mGestureState = eGestureState_None;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)rotateWithEvent:(NSEvent*)anEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!anEvent || !mGeckoChild ||
+      [self beginOrEndGestureForEventPhase:anEvent]) {
+    return;
+  }
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  float rotation = [anEvent rotation];
+
+  EventMessage msg;
+  switch (mGestureState) {
+    case eGestureState_StartGesture:
+      msg = eRotateGestureStart;
+      mGestureState = eGestureState_RotateGesture;
+      break;
+
+    case eGestureState_RotateGesture:
+      msg = eRotateGestureUpdate;
+      break;
+
+    case eGestureState_None:
+    case eGestureState_MagnifyGesture:
+    default:
+      return;
+  }
+
+  // Setup the event.
+  WidgetSimpleGestureEvent geckoEvent(true, msg, mGeckoChild);
+  [self convertCocoaMouseEvent:anEvent toGeckoEvent:&geckoEvent];
+  geckoEvent.mDelta = -rotation;
+  if (rotation > 0.0) {
+    geckoEvent.mDirection =
+        dom::SimpleGestureEvent_Binding::ROTATION_COUNTERCLOCKWISE;
+  } else {
+    geckoEvent.mDirection = dom::SimpleGestureEvent_Binding::ROTATION_CLOCKWISE;
+  }
+
+  // Send the event.
+  mGeckoChild->DispatchWindowEvent(geckoEvent);
+
+  // Keep track of the cumulative rotation for the final "rotate" event.
+  mCumulativeRotation += rotation;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// `beginGestureWithEvent` and `endGestureWithEvent` are not called for
+// applications that link against the macOS 10.11 or later SDK when we're
+// running on macOS 10.11 or later. For compatibility with all supported macOS
+// versions, we have to call {begin,end}GestureWithEvent ourselves based on
+// the event phase when we're handling gestures.
+- (bool)beginOrEndGestureForEventPhase:(NSEvent*)aEvent {
+  if (!aEvent) {
+    return false;
+  }
+
+  if (aEvent.phase == NSEventPhaseBegan) {
+    [self beginGestureWithEvent:aEvent];
+    return true;
+  }
+
+  if (aEvent.phase == NSEventPhaseEnded ||
+      aEvent.phase == NSEventPhaseCancelled) {
+    [self endGestureWithEvent:aEvent];
+    return true;
+  }
+
+  return false;
+}
+
+- (void)beginGestureWithEvent:(NSEvent*)aEvent {
+  if (!aEvent) {
+    return;
+  }
+
+  mGestureState = eGestureState_StartGesture;
+  mCumulativeRotation = 0.0;
+}
+
+- (void)endGestureWithEvent:(NSEvent*)anEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!anEvent || !mGeckoChild) {
+    // Clear the gestures state if we cannot send an event.
+    mGestureState = eGestureState_None;
+    mCumulativeRotation = 0.0;
+    return;
+  }
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  switch (mGestureState) {
+    case eGestureState_RotateGesture: {
+      // Setup the "rotate" event.
+      WidgetSimpleGestureEvent geckoEvent(true, eRotateGesture, mGeckoChild);
+      [self convertCocoaMouseEvent:anEvent toGeckoEvent:&geckoEvent];
+      geckoEvent.mDelta = -mCumulativeRotation;
+      if (mCumulativeRotation > 0.0) {
+        geckoEvent.mDirection =
+            dom::SimpleGestureEvent_Binding::ROTATION_COUNTERCLOCKWISE;
+      } else {
+        geckoEvent.mDirection =
+            dom::SimpleGestureEvent_Binding::ROTATION_CLOCKWISE;
+      }
+
+      // Send the event.
+      mGeckoChild->DispatchWindowEvent(geckoEvent);
+    } break;
+
+    case eGestureState_MagnifyGesture:  // APZ handles sending the widget events
+    case eGestureState_None:
+    case eGestureState_StartGesture:
+    default:
+      break;
+  }
+
+  // Clear the gestures state.
+  mGestureState = eGestureState_None;
+  mCumulativeRotation = 0.0;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)setUsingOMTCompositor:(BOOL)aUseOMTC {
+  mUsingOMTCompositor = aUseOMTC;
+}
+
+// Returning NO from this method only disallows ordering on mousedown - in order
+// to prevent it for mouseup too, we need to call [NSApp preventWindowOrdering]
+// when handling the mousedown event.
+- (BOOL)shouldDelayWindowOrderingForEvent:(NSEvent*)aEvent {
+  // Always using system-provided window ordering for normal windows.
+  if (![[self window] isKindOfClass:[PopupWindow class]]) return NO;
+
+  // Don't reorder when we don't have a parent window, like when we're a
+  // context menu or a tooltip.
+  return ![[self window] parentWindow];
+}
+
+- (void)mouseDown:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+  mPerformedDrag = NO;
+
+  if ([self shouldDelayWindowOrderingForEvent:theEvent]) {
+    [NSApp preventWindowOrdering];
+  }
+
+  // If we've already seen this event due to direct dispatch from menuForEvent:
+  // just bail; if not, remember it.
+  if (mLastMouseDownEvent == theEvent) {
+    [mLastMouseDownEvent release];
+    mLastMouseDownEvent = nil;
+    return;
+  } else {
+    [mLastMouseDownEvent release];
+    mLastMouseDownEvent = [theEvent retain];
+  }
+
+  [gLastDragMouseDownEvent release];
+  gLastDragMouseDownEvent = [theEvent retain];
+  gLastDragView = self;
+
+  // We need isClickThrough because at this point the window we're in might
+  // already have become main, so the check for isMainWindow in
+  // WindowAcceptsEvent isn't enough. It also has to check isClickThrough.
+  BOOL isClickThrough = (theEvent == mClickThroughMouseDownEvent);
+  [mClickThroughMouseDownEvent release];
+  mClickThroughMouseDownEvent = nil;
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  if ([self maybeRollup:theEvent] ||
+      !ChildViewMouseTracker::WindowAcceptsEvent([self window], theEvent, self,
+                                                 isClickThrough)) {
+    // Remember blocking because that means we want to block mouseup as well.
+    mBlockedLastMouseDown = YES;
+    return;
+  }
+
+  // in order to send gecko events we'll need a gecko widget
+  if (!mGeckoChild) return;
+  if (mTextInputHandler->OnHandleEvent(theEvent)) {
+    return;
+  }
+
+  WidgetMouseEvent geckoEvent(true, eMouseDown, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
+
+  NSInteger clickCount = [theEvent clickCount];
+  if (mBlockedLastMouseDown && clickCount > 1) {
+    // Don't send a double click if the first click of the double click was
+    // blocked.
+    clickCount--;
+  }
+  geckoEvent.mClickCount = clickCount;
+
+  if (!StaticPrefs::dom_event_treat_ctrl_click_as_right_click_disabled() &&
+      geckoEvent.IsControl()) {
+    geckoEvent.mButton = MouseButton::eSecondary;
+  } else {
+    geckoEvent.mButton = MouseButton::ePrimary;
+    // Don't send a click if ctrl key is pressed.
+    geckoEvent.mClickEventPrevented = geckoEvent.IsControl();
+  }
+
+  mGeckoChild->DispatchInputEvent(&geckoEvent);
+  mBlockedLastMouseDown = NO;
+
+  // XXX maybe call markedTextSelectionChanged:client: here?
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)mouseUp:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  gLastDragView = nil;
+
+  if (!mGeckoChild || mBlockedLastMouseDown || mPerformedDrag) {
+    // There is case that mouseUp event will be fired right after DnD on OSX. As
+    // mPerformedDrag will be YES at end of DnD processing, ignore this mouseUp
+    // event fired right after DnD.
+    return;
+  }
+
+  if (mTextInputHandler->OnHandleEvent(theEvent)) {
+    return;
+  }
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  WidgetMouseEvent geckoEvent(true, eMouseUp, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
+
+  if (!StaticPrefs::dom_event_treat_ctrl_click_as_right_click_disabled() &&
+      ([theEvent modifierFlags] & NSEventModifierFlagControl)) {
+    geckoEvent.mButton = MouseButton::eSecondary;
+  } else {
+    geckoEvent.mButton = MouseButton::ePrimary;
+  }
+
+  // Remember the event's position before calling DispatchInputEvent, because
+  // that call can mutate it and convert it into a different coordinate space.
+  LayoutDeviceIntPoint pos = geckoEvent.mRefPoint;
+
+  // This might destroy our widget (and null out mGeckoChild).
+  bool defaultPrevented =
+      (mGeckoChild->DispatchInputEvent(&geckoEvent).mContentStatus ==
+       nsEventStatus_eConsumeNoDefault);
+
+  if (!mGeckoChild) {
+    return;
+  }
+
+  // Check to see if we are double-clicking in draggable parts of the window.
+  if (!defaultPrevented && [theEvent clickCount] == 2 &&
+      !mGeckoChild->GetNonDraggableRegion().Contains(pos.x, pos.y)) {
+    if (nsCocoaUtils::ShouldZoomOnTitlebarDoubleClick()) {
+      [[self window] performZoom:nil];
+    } else if (nsCocoaUtils::ShouldMinimizeOnTitlebarDoubleClick()) {
+      [[self window] performMiniaturize:nil];
+    }
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)sendMouseEnterOrExitEvent:(NSEvent*)aEvent
+                            enter:(BOOL)aEnter
+                         exitFrom:(WidgetMouseEvent::ExitFrom)aExitFrom {
+  if (!mGeckoChild) return;
+
+  NSPoint windowEventLocation =
+      nsCocoaUtils::EventLocationForWindow(aEvent, [self window]);
+  NSPoint localEventLocation = [self convertPoint:windowEventLocation
+                                         fromView:nil];
+
+  EventMessage msg = aEnter ? eMouseEnterIntoWidget : eMouseExitFromWidget;
+  WidgetMouseEvent event(true, msg, mGeckoChild, WidgetMouseEvent::eReal);
+  event.mRefPoint = mGeckoChild->CocoaPointsToDevPixels(localEventLocation);
+  if (event.mMessage == eMouseExitFromWidget) {
+    event.mExitFrom = Some(aExitFrom);
+  }
+  nsEventStatus status;  // ignored
+  mGeckoChild->DispatchEvent(&event, status);
+}
+
+- (void)handleMouseMoved:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mGeckoChild) return;
+  if (mTextInputHandler->OnHandleEvent(theEvent)) {
+    return;
+  }
+
+  WidgetMouseEvent geckoEvent(true, eMouseMove, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
+
+  mGeckoChild->DispatchInputEvent(&geckoEvent);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)mouseDragged:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mGeckoChild) return;
+  if (mTextInputHandler->OnHandleEvent(theEvent)) {
+    return;
+  }
+
+  WidgetMouseEvent geckoEvent(true, eMouseMove, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
+
+  mGeckoChild->DispatchInputEvent(&geckoEvent);
+
+  // Note, sending the above event might have destroyed our widget since we
+  // didn't retain. Fine so long as we don't access any local variables from
+  // here on.
+
+  // XXX maybe call markedTextSelectionChanged:client: here?
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)rightMouseDown:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+  mPerformedDrag = NO;
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  [self maybeRollup:theEvent];
+  if (!mGeckoChild) return;
+  if (mTextInputHandler->OnHandleEvent(theEvent)) {
+    return;
+  }
+
+  // The right mouse went down, fire off a right mouse down event to gecko
+  WidgetMouseEvent geckoEvent(true, eMouseDown, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
+  geckoEvent.mButton = MouseButton::eSecondary;
+  geckoEvent.mClickCount = [theEvent clickCount];
+
+  nsIWidget::ContentAndAPZEventStatus eventStatus =
+      mGeckoChild->DispatchInputEvent(&geckoEvent);
+  if (!mGeckoChild) return;
+
+  if (!StaticPrefs::ui_context_menus_after_mouseup() &&
+      eventStatus.mApzStatus != nsEventStatus_eConsumeNoDefault) {
+    // Let the superclass do the context menu stuff.
+    [super rightMouseDown:theEvent];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)rightMouseUp:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mGeckoChild) return;
+  if (mTextInputHandler->OnHandleEvent(theEvent)) {
+    return;
+  }
+
+  WidgetMouseEvent geckoEvent(true, eMouseUp, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
+  geckoEvent.mButton = MouseButton::eSecondary;
+  geckoEvent.mClickCount = [theEvent clickCount];
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+  nsIWidget::ContentAndAPZEventStatus eventStatus =
+      mGeckoChild->DispatchInputEvent(&geckoEvent);
+  if (!mGeckoChild) return;
+
+  if (StaticPrefs::ui_context_menus_after_mouseup() &&
+      eventStatus.mApzStatus != nsEventStatus_eConsumeNoDefault) {
+    // Let the superclass do the context menu stuff, but pretend it's
+    // rightMouseDown.
+    NSEvent* dupeEvent = [NSEvent mouseEventWithType:NSEventTypeRightMouseDown
+                                            location:theEvent.locationInWindow
+                                       modifierFlags:theEvent.modifierFlags
+                                           timestamp:theEvent.timestamp
+                                        windowNumber:theEvent.windowNumber
+                                             context:nil
+                                         eventNumber:theEvent.eventNumber
+                                          clickCount:theEvent.clickCount
+                                            pressure:theEvent.pressure];
+
+    [super rightMouseDown:dupeEvent];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)rightMouseDragged:(NSEvent*)theEvent {
+  if (!mGeckoChild) return;
+  if (mTextInputHandler->OnHandleEvent(theEvent)) {
+    return;
+  }
+
+  WidgetMouseEvent geckoEvent(true, eMouseMove, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
+  geckoEvent.mButton = MouseButton::eSecondary;
+
+  // send event into Gecko by going directly to the
+  // the widget.
+  mGeckoChild->DispatchInputEvent(&geckoEvent);
+}
+
+static bool ShouldDispatchBackForwardCommandForMouseButton(int16_t aButton) {
+  return (aButton == MouseButton::eX1 &&
+          Preferences::GetBool("mousebutton.4th.enabled", true)) ||
+         (aButton == MouseButton::eX2 &&
+          Preferences::GetBool("mousebutton.5th.enabled", true));
+}
+
+- (void)otherMouseDown:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+  mPerformedDrag = NO;
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  if ([self maybeRollup:theEvent] ||
+      !ChildViewMouseTracker::WindowAcceptsEvent([self window], theEvent, self))
+    return;
+
+  if (!mGeckoChild) return;
+  if (mTextInputHandler->OnHandleEvent(theEvent)) {
+    return;
+  }
+
+  int16_t button = nsCocoaUtils::ButtonForEvent(theEvent);
+  if (ShouldDispatchBackForwardCommandForMouseButton(button)) {
+    WidgetCommandEvent appCommandEvent(
+        true,
+        (button == MouseButton::eX2) ? nsGkAtoms::Forward : nsGkAtoms::Back,
+        mGeckoChild);
+    mGeckoChild->DispatchWindowEvent(appCommandEvent);
+    return;
+  }
+
+  WidgetMouseEvent geckoEvent(true, eMouseDown, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
+  geckoEvent.mButton = button;
+  geckoEvent.mClickCount = [theEvent clickCount];
+
+  mGeckoChild->DispatchInputEvent(&geckoEvent);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)otherMouseUp:(NSEvent*)theEvent {
+  if (!mGeckoChild) return;
+  if (mTextInputHandler->OnHandleEvent(theEvent)) {
+    return;
+  }
+
+  int16_t button = nsCocoaUtils::ButtonForEvent(theEvent);
+  if (ShouldDispatchBackForwardCommandForMouseButton(button)) {
+    return;
+  }
+
+  WidgetMouseEvent geckoEvent(true, eMouseUp, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
+  geckoEvent.mButton = button;
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+  mGeckoChild->DispatchInputEvent(&geckoEvent);
+}
+
+- (void)otherMouseDragged:(NSEvent*)theEvent {
+  if (!mGeckoChild) return;
+  if (mTextInputHandler->OnHandleEvent(theEvent)) {
+    return;
+  }
+
+  WidgetMouseEvent geckoEvent(true, eMouseMove, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
+  int16_t button = nsCocoaUtils::ButtonForEvent(theEvent);
+  geckoEvent.mButton = button;
+
+  // send event into Gecko by going directly to the
+  // the widget.
+  mGeckoChild->DispatchInputEvent(&geckoEvent);
+}
+
+- (void)sendWheelStartOrStop:(EventMessage)msg forEvent:(NSEvent*)theEvent {
+  WidgetWheelEvent wheelEvent(true, msg, mGeckoChild);
+  [self convertCocoaMouseWheelEvent:theEvent toGeckoEvent:&wheelEvent];
+  mExpectingWheelStop = (msg == eWheelOperationStart);
+  mGeckoChild->DispatchInputEvent(wheelEvent.AsInputEvent());
+}
+
+- (void)sendWheelCondition:(BOOL)condition
+                     first:(EventMessage)first
+                    second:(EventMessage)second
+                  forEvent:(NSEvent*)theEvent {
+  if (mExpectingWheelStop == condition) {
+    [self sendWheelStartOrStop:first forEvent:theEvent];
+  }
+  [self sendWheelStartOrStop:second forEvent:theEvent];
+}
+
+static int32_t RoundUp(double aDouble) {
+  return aDouble < 0 ? static_cast<int32_t>(floor(aDouble))
+                     : static_cast<int32_t>(ceil(aDouble));
+}
+
+static gfx::IntPoint GetIntegerDeltaForEvent(NSEvent* aEvent) {
+  if ([aEvent hasPreciseScrollingDeltas]) {
+    // Pixel scroll events (events with hasPreciseScrollingDeltas == YES)
+    // carry pixel deltas in the scrollingDeltaX/Y fields and line scroll
+    // information in the deltaX/Y fields.
+    // Prior to 10.12, these line scroll fields would be zero for most pixel
+    // scroll events and non-zero for some, whenever at least a full line
+    // worth of pixel scrolling had accumulated. That's the behavior we want.
+    // Starting with 10.12 however, pixel scroll events no longer accumulate
+    // deltaX and deltaY; they just report floating point values for every
+    // single event. So we need to do our own accumulation.
+    return PanGestureInput::GetIntegerDeltaForEvent(
+        [aEvent phase] == NSEventPhaseBegan, [aEvent deltaX], [aEvent deltaY]);
+  }
+
+  // For line scrolls, or pre-10.12, just use the rounded up value of deltaX /
+  // deltaY.
+  return gfx::IntPoint(RoundUp([aEvent deltaX]), RoundUp([aEvent deltaY]));
+}
+
+- (void)scrollWheel:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  ChildViewMouseTracker::MouseScrolled(theEvent);
+
+  if ([self maybeRollup:theEvent]) {
+    return;
+  }
+
+  if (!mGeckoChild) {
+    return;
+  }
+
+  NSEventPhase phase = [theEvent phase];
+  // Fire eWheelOperationStart/End events when 2 fingers touch/release the
+  // touchpad.
+  if (phase & NSEventPhaseMayBegin) {
+    [self sendWheelCondition:YES
+                       first:eWheelOperationEnd
+                      second:eWheelOperationStart
+                    forEvent:theEvent];
+  } else if (phase & (NSEventPhaseEnded | NSEventPhaseCancelled)) {
+    [self sendWheelCondition:NO
+                       first:eWheelOperationStart
+                      second:eWheelOperationEnd
+                    forEvent:theEvent];
+  }
+
+  if (!mGeckoChild) {
+    return;
+  }
+  RefPtr<nsChildView> geckoChildDeathGrip(mGeckoChild);
+
+  NSPoint locationInWindow =
+      nsCocoaUtils::EventLocationForWindow(theEvent, [self window]);
+
+  // Use convertWindowCoordinatesRoundDown when converting the position to
+  // integer screen pixels in order to ensure that coordinates which are just
+  // inside the right / bottom edges of the window don't end up outside of the
+  // window after rounding.
+  ScreenPoint position = ViewAs<ScreenPixel>(
+      [self convertWindowCoordinatesRoundDown:locationInWindow],
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+
+  bool usePreciseDeltas =
+      [theEvent hasPreciseScrollingDeltas] &&
+      Preferences::GetBool("mousewheel.enable_pixel_scrolling", true);
+  bool hasPhaseInformation = nsCocoaUtils::EventHasPhaseInformation(theEvent);
+
+  gfx::IntPoint lineOrPageDelta = -GetIntegerDeltaForEvent(theEvent);
+
+  Modifiers modifiers = nsCocoaUtils::ModifiersForEvent(theEvent);
+
+  TimeStamp eventTimeStamp =
+      nsCocoaUtils::GetEventTimeStamp([theEvent timestamp]);
+
+  ScreenPoint preciseDelta;
+  if (usePreciseDeltas) {
+    CGFloat pixelDeltaX = [theEvent scrollingDeltaX];
+    CGFloat pixelDeltaY = [theEvent scrollingDeltaY];
+    double scale = geckoChildDeathGrip->BackingScaleFactor();
+    preciseDelta = ScreenPoint(-pixelDeltaX * scale, -pixelDeltaY * scale);
+  }
+
+  if (usePreciseDeltas && hasPhaseInformation) {
+    PanGestureInput panEvent = nsCocoaUtils::CreatePanGestureEvent(
+        theEvent, eventTimeStamp, position, preciseDelta, lineOrPageDelta,
+        modifiers);
+
+    geckoChildDeathGrip->DispatchAPZWheelInputEvent(panEvent);
+  } else if (usePreciseDeltas) {
+    // This is on 10.6 or old touchpads that don't have any phase information.
+    ScrollWheelInput wheelEvent(eventTimeStamp, modifiers,
+                                ScrollWheelInput::SCROLLMODE_INSTANT,
+                                ScrollWheelInput::SCROLLDELTA_PIXEL, position,
+                                preciseDelta.x, preciseDelta.y, false,
+                                // This parameter is used for wheel delta
+                                // adjustment, such as auto-dir scrolling,
+                                // but we do't need to do anything special here
+                                // since this wheel event is sent to
+                                // DispatchAPZWheelInputEvent, which turns this
+                                // ScrollWheelInput back into a WidgetWheelEvent
+                                // and then it goes through the regular handling
+                                // in APZInputBridge. So passing |eNone| won't
+                                // pass up the necessary wheel delta adjustment.
+                                WheelDeltaAdjustmentStrategy::eNone);
+    wheelEvent.mLineOrPageDeltaX = lineOrPageDelta.x;
+    wheelEvent.mLineOrPageDeltaY = lineOrPageDelta.y;
+    wheelEvent.mIsMomentum = nsCocoaUtils::IsMomentumScrollEvent(theEvent);
+    geckoChildDeathGrip->DispatchAPZWheelInputEvent(wheelEvent);
+  } else {
+    ScrollWheelInput::ScrollMode scrollMode =
+        ScrollWheelInput::SCROLLMODE_INSTANT;
+    if (StaticPrefs::general_smoothScroll() &&
+        StaticPrefs::general_smoothScroll_mouseWheel()) {
+      scrollMode = ScrollWheelInput::SCROLLMODE_SMOOTH;
+    }
+    ScrollWheelInput wheelEvent(eventTimeStamp, modifiers, scrollMode,
+                                ScrollWheelInput::SCROLLDELTA_LINE, position,
+                                lineOrPageDelta.x, lineOrPageDelta.y, false,
+                                // This parameter is used for wheel delta
+                                // adjustment, such as auto-dir scrolling,
+                                // but we do't need to do anything special here
+                                // since this wheel event is sent to
+                                // DispatchAPZWheelInputEvent, which turns this
+                                // ScrollWheelInput back into a WidgetWheelEvent
+                                // and then it goes through the regular handling
+                                // in APZInputBridge. So passing |eNone| won't
+                                // pass up the necessary wheel delta adjustment.
+                                WheelDeltaAdjustmentStrategy::eNone);
+    wheelEvent.mLineOrPageDeltaX = lineOrPageDelta.x;
+    wheelEvent.mLineOrPageDeltaY = lineOrPageDelta.y;
+    geckoChildDeathGrip->DispatchAPZWheelInputEvent(wheelEvent);
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (NSMenu*)menuForEvent:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!mGeckoChild) return nil;
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  [self maybeRollup:theEvent];
+  if (!mGeckoChild) return nil;
+
+  // Cocoa doesn't always dispatch a mouseDown: for a control-click event,
+  // depends on what we return from menuForEvent:. Gecko always expects one
+  // and expects the mouse down event before the context menu event, so
+  // get that event sent first if this is a left mouse click.
+  if ([theEvent type] == NSEventTypeLeftMouseDown) {
+    [self mouseDown:theEvent];
+    if (!mGeckoChild) return nil;
+  }
+
+  WidgetMouseEvent geckoEvent(true, eContextMenu, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:theEvent toGeckoEvent:&geckoEvent];
+  if (StaticPrefs::dom_event_treat_ctrl_click_as_right_click_disabled() &&
+      [theEvent type] == NSEventTypeLeftMouseDown) {
+    geckoEvent.mContextMenuTrigger = WidgetMouseEvent::eControlClick;
+    geckoEvent.mButton = MouseButton::ePrimary;
+  } else {
+    geckoEvent.mButton = MouseButton::eSecondary;
+  }
+
+  mGeckoChild->DispatchInputEvent(&geckoEvent);
+  if (!mGeckoChild) return nil;
+
+  [self maybeInitContextMenuTracking];
+
+  // We never return an actual NSMenu* for the context menu. Gecko might have
+  // responded to the eContextMenu event by putting up a fake context menu.
+  return nil;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (void)willOpenMenu:(NSMenu*)aMenu withEvent:(NSEvent*)aEvent {
+  ChildViewMouseTracker::NativeMenuOpened();
+}
+
+- (void)didCloseMenu:(NSMenu*)aMenu withEvent:(NSEvent*)aEvent {
+  ChildViewMouseTracker::NativeMenuClosed();
+}
+
+- (void)convertCocoaMouseWheelEvent:(NSEvent*)aMouseEvent
+                       toGeckoEvent:(WidgetWheelEvent*)outWheelEvent {
+  [self convertCocoaMouseEvent:aMouseEvent toGeckoEvent:outWheelEvent];
+
+  bool usePreciseDeltas =
+      [aMouseEvent hasPreciseScrollingDeltas] &&
+      Preferences::GetBool("mousewheel.enable_pixel_scrolling", true);
+
+  outWheelEvent->mDeltaMode = usePreciseDeltas
+                                  ? dom::WheelEvent_Binding::DOM_DELTA_PIXEL
+                                  : dom::WheelEvent_Binding::DOM_DELTA_LINE;
+  outWheelEvent->mIsMomentum = nsCocoaUtils::IsMomentumScrollEvent(aMouseEvent);
+}
+
+- (void)convertCocoaMouseEvent:(NSEvent*)aMouseEvent
+                  toGeckoEvent:(WidgetInputEvent*)outGeckoEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NS_ASSERTION(
+      outGeckoEvent,
+      "convertCocoaMouseEvent:toGeckoEvent: requires non-null aoutGeckoEvent");
+  if (!outGeckoEvent) return;
+
+  nsCocoaUtils::InitInputEvent(*outGeckoEvent, aMouseEvent);
+
+  // convert point to view coordinate system
+  NSPoint locationInWindow =
+      nsCocoaUtils::EventLocationForWindow(aMouseEvent, [self window]);
+
+  outGeckoEvent->mRefPoint = [self convertWindowCoordinates:locationInWindow];
+
+  WidgetMouseEventBase* mouseEvent = outGeckoEvent->AsMouseEventBase();
+  mouseEvent->mButtons = 0;
+  NSUInteger mouseButtons = [NSEvent pressedMouseButtons];
+
+  if (mouseButtons & 0x01) {
+    mouseEvent->mButtons |= MouseButtonsFlag::ePrimaryFlag;
+  }
+  if (mouseButtons & 0x02) {
+    mouseEvent->mButtons |= MouseButtonsFlag::eSecondaryFlag;
+  }
+  if (mouseButtons & 0x04) {
+    mouseEvent->mButtons |= MouseButtonsFlag::eMiddleFlag;
+  }
+  if (mouseButtons & 0x08) {
+    mouseEvent->mButtons |= MouseButtonsFlag::e4thFlag;
+  }
+  if (mouseButtons & 0x10) {
+    mouseEvent->mButtons |= MouseButtonsFlag::e5thFlag;
+  }
+
+  switch ([aMouseEvent type]) {
+    case NSEventTypeLeftMouseDown:
+    case NSEventTypeLeftMouseUp:
+    case NSEventTypeLeftMouseDragged:
+    case NSEventTypeRightMouseDown:
+    case NSEventTypeRightMouseUp:
+    case NSEventTypeRightMouseDragged:
+    case NSEventTypeOtherMouseDown:
+    case NSEventTypeOtherMouseUp:
+    case NSEventTypeOtherMouseDragged:
+    case NSEventTypeMouseMoved:
+      if ([aMouseEvent subtype] == NSEventSubtypeTabletPoint) {
+        [self convertCocoaTabletPointerEvent:aMouseEvent
+                                toGeckoEvent:mouseEvent->AsMouseEvent()];
+      }
+      break;
+
+    default:
+      // Don't check other NSEvents for pressure.
+      break;
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)convertCocoaTabletPointerEvent:(NSEvent*)aPointerEvent
+                          toGeckoEvent:(WidgetMouseEvent*)aOutGeckoEvent {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+  if (!aOutGeckoEvent || !sIsTabletPointerActivated) {
+    return;
+  }
+  if ([aPointerEvent type] != NSEventTypeMouseMoved) {
+    aOutGeckoEvent->mPressure = [aPointerEvent pressure];
+    MOZ_ASSERT(aOutGeckoEvent->mPressure >= 0.0 &&
+               aOutGeckoEvent->mPressure <= 1.0);
+  }
+  aOutGeckoEvent->mInputSource = dom::MouseEvent_Binding::MOZ_SOURCE_PEN;
+  aOutGeckoEvent->tiltX = (int32_t)lround([aPointerEvent tilt].x * 90);
+  aOutGeckoEvent->tiltY = (int32_t)lround([aPointerEvent tilt].y * 90);
+  aOutGeckoEvent->tangentialPressure = [aPointerEvent tangentialPressure];
+  // Make sure the twist value is in the range of 0-359.
+  int32_t twist = (int32_t)fmod([aPointerEvent rotation], 360);
+  aOutGeckoEvent->twist = twist >= 0 ? twist : twist + 360;
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)tabletProximity:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+  sIsTabletPointerActivated = [theEvent isEnteringProximity];
+  NS_OBJC_END_TRY_IGNORE_BLOCK
+}
+
+#pragma mark -
+// NSTextInputClient implementation
+
+- (NSRange)markedRange {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NS_ENSURE_TRUE(mTextInputHandler, NSMakeRange(NSNotFound, 0));
+  return mTextInputHandler->MarkedRange();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NSMakeRange(0, 0));
+}
+
+- (NSRange)selectedRange {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NS_ENSURE_TRUE(mTextInputHandler, NSMakeRange(NSNotFound, 0));
+  return mTextInputHandler->SelectedRange();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NSMakeRange(0, 0));
+}
+
+- (BOOL)drawsVerticallyForCharacterAtIndex:(NSUInteger)charIndex {
+  NS_ENSURE_TRUE(mTextInputHandler, NO);
+  if (charIndex == NSNotFound) {
+    return NO;
+  }
+  return mTextInputHandler->DrawsVerticallyForCharacterAtIndex(charIndex);
+}
+
+- (NSUInteger)characterIndexForPoint:(NSPoint)thePoint {
+  NS_ENSURE_TRUE(mTextInputHandler, 0);
+  return mTextInputHandler->CharacterIndexForPoint(thePoint);
+}
+
+- (NSArray*)validAttributesForMarkedText {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NS_ENSURE_TRUE(mTextInputHandler, [NSArray array]);
+  return mTextInputHandler->GetValidAttributesForMarkedText();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (void)insertText:(id)aString replacementRange:(NSRange)replacementRange {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NS_ENSURE_TRUE_VOID(mGeckoChild);
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  NSString* str;
+  if ([aString isKindOfClass:[NSAttributedString class]]) {
+    str = [aString string];
+  } else {
+    str = aString;
+  }
+
+  mTextInputHandler->InsertText(str, &replacementRange);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)doCommandBySelector:(SEL)aSelector {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mGeckoChild || !mTextInputHandler) {
+    return;
+  }
+
+  const char* sel = reinterpret_cast<const char*>(aSelector);
+  if (!mTextInputHandler->DoCommandBySelector(sel)) {
+    [super doCommandBySelector:aSelector];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)unmarkText {
+  NS_ENSURE_TRUE_VOID(mTextInputHandler);
+  mTextInputHandler->CommitIMEComposition();
+}
+
+- (BOOL)hasMarkedText {
+  NS_ENSURE_TRUE(mTextInputHandler, NO);
+  return mTextInputHandler->HasMarkedText();
+}
+
+- (void)setMarkedText:(id)aString
+        selectedRange:(NSRange)selectedRange
+     replacementRange:(NSRange)replacementRange {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NS_ENSURE_TRUE_VOID(mTextInputHandler);
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  NSAttributedString* attrStr;
+  if ([aString isKindOfClass:[NSAttributedString class]]) {
+    attrStr = static_cast<NSAttributedString*>(aString);
+  } else {
+    attrStr = [[[NSAttributedString alloc] initWithString:aString] autorelease];
+  }
+
+  mTextInputHandler->SetMarkedText(attrStr, selectedRange, &replacementRange);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (NSAttributedString*)attributedSubstringForProposedRange:(NSRange)aRange
+                                               actualRange:
+                                                   (NSRangePointer)actualRange {
+  NS_ENSURE_TRUE(mTextInputHandler, nil);
+  return mTextInputHandler->GetAttributedSubstringFromRange(aRange,
+                                                            actualRange);
+}
+
+- (NSRect)firstRectForCharacterRange:(NSRange)aRange
+                         actualRange:(NSRangePointer)actualRange {
+  NS_ENSURE_TRUE(mTextInputHandler, NSMakeRect(0.0, 0.0, 0.0, 0.0));
+  return mTextInputHandler->FirstRectForCharacterRange(aRange, actualRange);
+}
+
+- (void)quickLookWithEvent:(NSEvent*)event {
+  // Show dictionary by current point
+  WidgetContentCommandEvent contentCommandEvent(
+      true, eContentCommandLookUpDictionary, mGeckoChild);
+  NSPoint point = [self convertPoint:[event locationInWindow] fromView:nil];
+  contentCommandEvent.mRefPoint = mGeckoChild->CocoaPointsToDevPixels(point);
+  mGeckoChild->DispatchWindowEvent(contentCommandEvent);
+  // The widget might have been destroyed.
+}
+
+- (NSInteger)windowLevel {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NS_ENSURE_TRUE(mTextInputHandler, [[self window] level]);
+  return mTextInputHandler->GetWindowLevel();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NSNormalWindowLevel);
+}
+
+#pragma mark -
+
+// This is a private API that Cocoa uses.
+// Cocoa will call this after the menu system returns "NO" for
+// "performKeyEquivalent:". We want all they key events we can get so just
+// return YES. In particular, this fixes ctrl-tab - we don't get a "keyDown:"
+// call for that without this.
+- (BOOL)_wantsKeyDownForEvent:(NSEvent*)event {
+  return YES;
+}
+
+- (NSEvent*)lastKeyDownEvent {
+  return mLastKeyDownEvent;
+}
+
+- (void)keyDown:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [mLastKeyDownEvent release];
+  mLastKeyDownEvent = [theEvent retain];
+
+  // Weird things can happen on keyboard input if the key window isn't in the
+  // current space.  For example see bug 1056251.  To get around this, always
+  // make sure that, if our window is key, it's also made frontmost.  Doing
+  // this automatically switches to whatever space our window is in.  Safari
+  // does something similar.  Our window should normally always be key --
+  // otherwise why is the OS sending us a key down event?  But it's just
+  // possible we're in Gecko's hidden window, so we check first.
+  NSWindow* viewWindow = [self window];
+  if (viewWindow && [viewWindow isKeyWindow]) {
+    [viewWindow orderWindow:NSWindowAbove relativeTo:0];
+  }
+
+#if !defined(RELEASE_OR_BETA) || defined(DEBUG)
+  if (!Preferences::GetBool("intl.allow-insecure-text-input", false) &&
+      mGeckoChild && mTextInputHandler && mTextInputHandler->IsFocused()) {
+    NSWindow* window = [self window];
+    NSString* info = [NSString
+        stringWithFormat:@"\nview [%@], window [%@], window is key %i, is "
+                         @"fullscreen %i, app is active %i",
+                         self, window, [window isKeyWindow],
+                         ([window styleMask] & NSWindowStyleMaskFullScreen) !=
+                             0,
+                         [NSApp isActive]];
+    nsAutoCString additionalInfo([info UTF8String]);
+
+    if (mGeckoChild->GetInputContext().IsPasswordEditor() &&
+        !TextInputHandler::IsSecureEventInputEnabled()) {
+#  define CRASH_MESSAGE \
+    "A password editor has focus, but not in secure input mode"
+
+      CrashReporter::AppendAppNotesToCrashReport(
+          "\nBug 893973: "_ns + nsLiteralCString(CRASH_MESSAGE));
+      CrashReporter::AppendAppNotesToCrashReport(additionalInfo);
+
+      MOZ_CRASH(CRASH_MESSAGE);
+#  undef CRASH_MESSAGE
+    } else if (!mGeckoChild->GetInputContext().IsPasswordEditor() &&
+               TextInputHandler::IsSecureEventInputEnabled()) {
+#  define CRASH_MESSAGE \
+    "A non-password editor has focus, but in secure input mode"
+
+      CrashReporter::AppendAppNotesToCrashReport(
+          "\nBug 893973: "_ns + nsLiteralCString(CRASH_MESSAGE));
+      CrashReporter::AppendAppNotesToCrashReport(additionalInfo);
+
+      MOZ_CRASH(CRASH_MESSAGE);
+#  undef CRASH_MESSAGE
+    }
+  }
+#endif  // #if !defined(RELEASE_OR_BETA) || defined(DEBUG)
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+  if (mGeckoChild) {
+    if (mTextInputHandler) {
+      sUniqueKeyEventId++;
+      NSMutableDictionary* nativeKeyEventsMap = [ChildView sNativeKeyEventsMap];
+      [nativeKeyEventsMap setObject:theEvent forKey:@(sUniqueKeyEventId)];
+      // Purge old native events, in case we're still holding on to them. We
+      // keep at most 10 references to 10 different native events.
+      [nativeKeyEventsMap removeObjectForKey:@(sUniqueKeyEventId - 10)];
+      mTextInputHandler->HandleKeyDownEvent(theEvent, sUniqueKeyEventId);
+    } else {
+      // There was no text input handler. Offer the event to the native menu
+      // system to check if there are any registered custom shortcuts for this
+      // event.
+      mGeckoChild->SendEventToNativeMenuSystem(theEvent);
+    }
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)keyUp:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NS_ENSURE_TRUE(mGeckoChild, );
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  mTextInputHandler->HandleKeyUpEvent(theEvent);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)insertNewline:(id)sender {
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::InsertParagraph);
+  }
+}
+
+- (void)insertLineBreak:(id)sender {
+  // Ctrl + Enter in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::InsertLineBreak);
+  }
+}
+
+- (void)deleteBackward:(id)sender {
+  // Backspace in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::DeleteCharBackward);
+  }
+}
+
+- (void)deleteBackwardByDecomposingPreviousCharacter:(id)sender {
+  // Ctrl + Backspace in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::DeleteCharBackward);
+  }
+}
+
+- (void)deleteWordBackward:(id)sender {
+  // Alt + Backspace in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::DeleteWordBackward);
+  }
+}
+
+- (void)deleteToBeginningOfBackward:(id)sender {
+  // Command + Backspace in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::DeleteToBeginningOfLine);
+  }
+}
+
+- (void)deleteForward:(id)sender {
+  // Delete in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::DeleteCharForward);
+  }
+}
+
+- (void)deleteWordForward:(id)sender {
+  // Alt + Delete in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::DeleteWordForward);
+  }
+}
+
+- (void)insertTab:(id)sender {
+  // Tab in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::InsertTab);
+  }
+}
+
+- (void)insertBacktab:(id)sender {
+  // Shift + Tab in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::InsertBacktab);
+  }
+}
+
+- (void)moveRight:(id)sender {
+  // RightArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::CharNext);
+  }
+}
+
+- (void)moveRightAndModifySelection:(id)sender {
+  // Shift + RightArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectCharNext);
+  }
+}
+
+- (void)moveWordRight:(id)sender {
+  // Alt + RightArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::WordNext);
+  }
+}
+
+- (void)moveWordRightAndModifySelection:(id)sender {
+  // Alt + Shift + RightArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectWordNext);
+  }
+}
+
+- (void)moveToRightEndOfLine:(id)sender {
+  // Command + RightArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::EndLine);
+  }
+}
+
+- (void)moveToRightEndOfLineAndModifySelection:(id)sender {
+  // Command + Shift + RightArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectEndLine);
+  }
+}
+
+- (void)moveLeft:(id)sender {
+  // LeftArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::CharPrevious);
+  }
+}
+
+- (void)moveLeftAndModifySelection:(id)sender {
+  // Shift + LeftArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectCharPrevious);
+  }
+}
+
+- (void)moveWordLeft:(id)sender {
+  // Alt + LeftArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::WordPrevious);
+  }
+}
+
+- (void)moveWordLeftAndModifySelection:(id)sender {
+  // Alt + Shift + LeftArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectWordPrevious);
+  }
+}
+
+- (void)moveToLeftEndOfLine:(id)sender {
+  // Command + LeftArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::BeginLine);
+  }
+}
+
+- (void)moveToLeftEndOfLineAndModifySelection:(id)sender {
+  // Command + Shift + LeftArrow in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectBeginLine);
+  }
+}
+
+- (void)moveUp:(id)sender {
+  // ArrowUp in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::LinePrevious);
+  }
+}
+
+- (void)moveUpAndModifySelection:(id)sender {
+  // Shift + ArrowUp in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectLinePrevious);
+  }
+}
+
+- (void)moveToBeginningOfDocument:(id)sender {
+  // Command + ArrowUp in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::MoveTop);
+  }
+}
+
+- (void)moveToBeginningOfDocumentAndModifySelection:(id)sender {
+  // Command + Shift + ArrowUp or Shift + Home in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectTop);
+  }
+}
+
+- (void)moveDown:(id)sender {
+  // ArrowDown in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::LineNext);
+  }
+}
+
+- (void)moveDownAndModifySelection:(id)sender {
+  // Shift + ArrowDown in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectLineNext);
+  }
+}
+
+- (void)moveToEndOfDocument:(id)sender {
+  // Command + ArrowDown in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::MoveBottom);
+  }
+}
+
+- (void)moveToEndOfDocumentAndModifySelection:(id)sender {
+  // Command + Shift + ArrowDown or Shift + End in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectBottom);
+  }
+}
+
+- (void)scrollPageUp:(id)sender {
+  // PageUp in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::ScrollPageUp);
+  }
+}
+
+- (void)pageUpAndModifySelection:(id)sender {
+  // Shift + PageUp in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectPageUp);
+  }
+}
+
+- (void)scrollPageDown:(id)sender {
+  // PageDown in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::ScrollPageDown);
+  }
+}
+
+- (void)pageDownAndModifySelection:(id)sender {
+  // Shift + PageDown in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::SelectPageDown);
+  }
+}
+
+- (void)scrollToEndOfDocument:(id)sender {
+  // End in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::ScrollBottom);
+  }
+}
+
+- (void)scrollToBeginningOfDocument:(id)sender {
+  // Home in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::ScrollTop);
+  }
+}
+
+// XXX Don't decleare nor implement calcelOperation: because it
+//     causes not calling keyDown: for Command + Period.
+//     We need to handle it from doCommandBySelector:.
+
+- (void)complete:(id)sender {
+  // Alt + Escape or Alt + Shift + Escape in the default settings.
+  if (mTextInputHandler) {
+    mTextInputHandler->HandleCommand(Command::Complete);
+  }
+}
+
+- (void)flagsChanged:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NS_ENSURE_TRUE(mGeckoChild, );
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+  mTextInputHandler->HandleFlagsChanged(theEvent);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (BOOL)isFirstResponder {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSResponder* resp = [[self window] firstResponder];
+  return (resp == (NSResponder*)self);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NO);
+}
+
+- (BOOL)isDragInProgress {
+  if (!mDragService) return NO;
+
+  nsCOMPtr<nsIDragSession> dragSession;
+  mDragService->GetCurrentSession(getter_AddRefs(dragSession));
+  return dragSession != nullptr;
+}
+
+- (BOOL)inactiveWindowAcceptsMouseEvent:(NSEvent*)aEvent {
+  // If we're being destroyed assume the default -- return YES.
+  if (!mGeckoChild) return YES;
+
+  WidgetMouseEvent geckoEvent(true, eMouseActivate, mGeckoChild,
+                              WidgetMouseEvent::eReal);
+  [self convertCocoaMouseEvent:aEvent toGeckoEvent:&geckoEvent];
+  return (mGeckoChild->DispatchInputEvent(&geckoEvent).mContentStatus !=
+          nsEventStatus_eConsumeNoDefault);
+}
+
+// We must always call through to our superclass, even when mGeckoChild is
+// nil -- otherwise the keyboard focus can end up in the wrong NSView.
+- (BOOL)becomeFirstResponder {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return [super becomeFirstResponder];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(YES);
+}
+
+- (void)viewsWindowDidBecomeKey {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mGeckoChild) return;
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  // check to see if the window implements the mozWindow protocol. This
+  // allows embedders to avoid re-entrant calls to -makeKeyAndOrderFront,
+  // which can happen because these activate calls propagate out
+  // to the embedder via nsIEmbeddingSiteWindow::SetFocus().
+  BOOL isMozWindow =
+      [[self window] respondsToSelector:@selector(setSuppressMakeKeyFront:)];
+  if (isMozWindow) [[self window] setSuppressMakeKeyFront:YES];
+
+  nsIWidgetListener* listener = mGeckoChild->GetWidgetListener();
+  if (listener) listener->WindowActivated();
+
+  if (isMozWindow) [[self window] setSuppressMakeKeyFront:NO];
+
+  if (mGeckoChild->GetInputContext().IsPasswordEditor()) {
+    TextInputHandler::EnableSecureEventInput();
+  } else {
+    TextInputHandler::EnsureSecureEventInputDisabled();
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)viewsWindowDidResignKey {
+  if (!mGeckoChild) return;
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  nsIWidgetListener* listener = mGeckoChild->GetWidgetListener();
+  if (listener) listener->WindowDeactivated();
+
+  TextInputHandler::EnsureSecureEventInputDisabled();
+}
+
+// If the call to removeFromSuperview isn't delayed from nsChildView::
+// TearDownView(), the NSView hierarchy might get changed during calls to
+// [ChildView drawRect:], which leads to "beyond bounds" exceptions in
+// NSCFArray.  For more info see bmo bug 373122.  Apple's docs claim that
+// removeFromSuperviewWithoutNeedingDisplay "can be safely invoked during
+// display" (whatever "display" means).  But it's _not_ true that it can be
+// safely invoked during calls to [NSView drawRect:].  We use
+// removeFromSuperview here because there's no longer any danger of being
+// "invoked during display", and because doing do clears up bmo bug 384343.
+- (void)delayedTearDown {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [self removeFromSuperview];
+  [self release];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+#pragma mark -
+
+// drag'n'drop stuff
+#define kDragServiceContractID "@mozilla.org/widget/dragservice;1"
+
+- (NSDragOperation)dragOperationFromDragAction:(int32_t)aDragAction {
+  if (nsIDragService::DRAGDROP_ACTION_LINK & aDragAction)
+    return NSDragOperationLink;
+  if (nsIDragService::DRAGDROP_ACTION_COPY & aDragAction)
+    return NSDragOperationCopy;
+  if (nsIDragService::DRAGDROP_ACTION_MOVE & aDragAction)
+    return NSDragOperationGeneric;
+  return NSDragOperationNone;
+}
+
+- (LayoutDeviceIntPoint)convertWindowCoordinates:(NSPoint)aPoint {
+  if (!mGeckoChild) {
+    return LayoutDeviceIntPoint(0, 0);
+  }
+
+  NSPoint localPoint = [self convertPoint:aPoint fromView:nil];
+  return mGeckoChild->CocoaPointsToDevPixels(localPoint);
+}
+
+- (LayoutDeviceIntPoint)convertWindowCoordinatesRoundDown:(NSPoint)aPoint {
+  if (!mGeckoChild) {
+    return LayoutDeviceIntPoint(0, 0);
+  }
+
+  NSPoint localPoint = [self convertPoint:aPoint fromView:nil];
+  return mGeckoChild->CocoaPointsToDevPixelsRoundDown(localPoint);
+}
+
+// This is a utility function used by NSView drag event methods
+// to send events. It contains all of the logic needed for Gecko
+// dragging to work. Returns the appropriate cocoa drag operation code.
+- (NSDragOperation)doDragAction:(EventMessage)aMessage sender:(id)aSender {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!mGeckoChild) return NSDragOperationNone;
+
+  MOZ_LOG(sCocoaLog, LogLevel::Info, ("ChildView doDragAction: entered\n"));
+
+  if (!mDragService) {
+    CallGetService(kDragServiceContractID, &mDragService);
+    NS_ASSERTION(mDragService, "Couldn't get a drag service - big problem!");
+    if (!mDragService) return NSDragOperationNone;
+  }
+
+  if (aMessage == eDragEnter) {
+    mDragService->StartDragSession();
+  }
+
+  nsCOMPtr<nsIDragSession> dragSession;
+  mDragService->GetCurrentSession(getter_AddRefs(dragSession));
+  if (dragSession) {
+    if (aMessage == eDragOver) {
+      // fire the drag event at the source. Just ignore whether it was
+      // cancelled or not as there isn't actually a means to stop the drag
+      nsCOMPtr<nsIDragService> dragService = mDragService;
+      dragService->FireDragEventAtSource(
+          eDrag, nsCocoaUtils::ModifiersForEvent([NSApp currentEvent]));
+      dragSession->SetCanDrop(false);
+    } else if (aMessage == eDrop) {
+      // We make the assumption that the dragOver handlers have correctly set
+      // the |canDrop| property of the Drag Session.
+      bool canDrop = false;
+      if (!NS_SUCCEEDED(dragSession->GetCanDrop(&canDrop)) || !canDrop) {
+        [self doDragAction:eDragExit sender:aSender];
+
+        nsCOMPtr<nsINode> sourceNode;
+        dragSession->GetSourceNode(getter_AddRefs(sourceNode));
+        if (!sourceNode) {
+          nsCOMPtr<nsIDragService> dragService = mDragService;
+          dragService->EndDragSession(
+              false, nsCocoaUtils::ModifiersForEvent([NSApp currentEvent]));
+        }
+        return NSDragOperationNone;
+      }
+    }
+
+    unsigned int modifierFlags = [[NSApp currentEvent] modifierFlags];
+    uint32_t action = nsIDragService::DRAGDROP_ACTION_MOVE;
+    // force copy = option, alias = cmd-option, default is move
+    if (modifierFlags & NSEventModifierFlagOption) {
+      if (modifierFlags & NSEventModifierFlagCommand)
+        action = nsIDragService::DRAGDROP_ACTION_LINK;
+      else
+        action = nsIDragService::DRAGDROP_ACTION_COPY;
+    }
+    dragSession->SetDragAction(action);
+  }
+
+  // set up gecko event
+  WidgetDragEvent geckoEvent(true, aMessage, mGeckoChild);
+  nsCocoaUtils::InitInputEvent(geckoEvent, [NSApp currentEvent]);
+
+  // Use our own coordinates in the gecko event.
+  // Convert event from gecko global coords to gecko view coords.
+  NSPoint draggingLoc = [aSender draggingLocation];
+
+  geckoEvent.mRefPoint = [self convertWindowCoordinates:draggingLoc];
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+  mGeckoChild->DispatchInputEvent(&geckoEvent);
+  if (!mGeckoChild) return NSDragOperationNone;
+
+  if (dragSession) {
+    switch (aMessage) {
+      case eDragEnter:
+      case eDragOver: {
+        uint32_t dragAction;
+        dragSession->GetDragAction(&dragAction);
+
+        // If TakeChildProcessDragAction returns something other than
+        // DRAGDROP_ACTION_UNINITIALIZED, it means that the last event was sent
+        // to the child process and this event is also being sent to the child
+        // process. In this case, use the last event's action instead.
+        nsDragService* dragService = static_cast<nsDragService*>(mDragService);
+        int32_t childDragAction = dragService->TakeChildProcessDragAction();
+        if (childDragAction != nsIDragService::DRAGDROP_ACTION_UNINITIALIZED) {
+          dragAction = childDragAction;
+        }
+
+        return [self dragOperationFromDragAction:dragAction];
+      }
+      case eDragExit:
+      case eDrop: {
+        nsCOMPtr<nsINode> sourceNode;
+        dragSession->GetSourceNode(getter_AddRefs(sourceNode));
+        if (!sourceNode) {
+          // We're leaving a window while doing a drag that was
+          // initiated in a different app. End the drag session,
+          // since we're done with it for now (until the user
+          // drags back into mozilla).
+          nsCOMPtr<nsIDragService> dragService = mDragService;
+          dragService->EndDragSession(
+              false, nsCocoaUtils::ModifiersForEvent([NSApp currentEvent]));
+        }
+        break;
+      }
+      default:
+        break;
+    }
+  }
+
+  return NSDragOperationGeneric;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NSDragOperationNone);
+}
+
+// NSDraggingDestination
+- (NSDragOperation)draggingEntered:(id<NSDraggingInfo>)sender {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_LOG(sCocoaLog, LogLevel::Info, ("ChildView draggingEntered: entered\n"));
+
+  // there should never be a globalDragPboard when "draggingEntered:" is
+  // called, but just in case we'll take care of it here.
+  [globalDragPboard release];
+
+  // Set the global drag pasteboard that will be used for this drag session.
+  // This will be set back to nil when the drag session ends (mouse exits
+  // the view or a drop happens within the view).
+  globalDragPboard = [[sender draggingPasteboard] retain];
+
+  return [self doDragAction:eDragEnter sender:sender];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NSDragOperationNone);
+}
+
+// NSDraggingDestination
+- (NSDragOperation)draggingUpdated:(id<NSDraggingInfo>)sender {
+  MOZ_LOG(sCocoaLog, LogLevel::Info, ("ChildView draggingUpdated: entered\n"));
+  return [self doDragAction:eDragOver sender:sender];
+}
+
+// NSDraggingDestination
+- (void)draggingExited:(id<NSDraggingInfo>)sender {
+  MOZ_LOG(sCocoaLog, LogLevel::Info, ("ChildView draggingExited: entered\n"));
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+  [self doDragAction:eDragExit sender:sender];
+  NS_IF_RELEASE(mDragService);
+}
+
+// NSDraggingDestination
+- (BOOL)performDragOperation:(id<NSDraggingInfo>)sender {
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+  BOOL handled = [self doDragAction:eDrop sender:sender] != NSDragOperationNone;
+  NS_IF_RELEASE(mDragService);
+  return handled;
+}
+
+// NSDraggingSource
+// This is just implemented so we comply with the NSDraggingSource protocol.
+- (NSDragOperation)draggingSession:(NSDraggingSession*)session
+    sourceOperationMaskForDraggingContext:(NSDraggingContext)context {
+  return UINT_MAX;
+}
+
+// NSDraggingSource
+- (BOOL)ignoreModifierKeysForDraggingSession:(NSDraggingSession*)session {
+  return YES;
+}
+
+// NSDraggingSource
+- (void)draggingSession:(NSDraggingSession*)aSession
+           endedAtPoint:(NSPoint)aPoint
+              operation:(NSDragOperation)aOperation {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+#ifdef NIGHTLY_BUILD
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+#endif
+
+  gDraggedTransferables = nullptr;
+
+  NSEvent* currentEvent = [NSApp currentEvent];
+  gUserCancelledDrag = ([currentEvent type] == NSEventTypeKeyDown &&
+                        [currentEvent keyCode] == kVK_Escape);
+
+  if (!mDragService) {
+    CallGetService(kDragServiceContractID, &mDragService);
+    NS_ASSERTION(mDragService, "Couldn't get a drag service - big problem!");
+  }
+
+  if (mDragService) {
+    RefPtr<nsDragService> dragService =
+        static_cast<nsDragService*>(mDragService);
+
+    // Set the dragend point from the current mouse location
+    // FIXME(emilio): Weird that we wouldn't use aPoint instead? Seems to work
+    // locally as well...
+    // NSPoint pnt = aPoint;
+    NSPoint pnt = [NSEvent mouseLocation];
+    NSPoint locationInWindow =
+        nsCocoaUtils::ConvertPointFromScreen([self window], pnt);
+    FlipCocoaScreenCoordinate(pnt);
+    dragService->SetDragEndPoint(
+        [self convertWindowCoordinates:locationInWindow]);
+
+    // XXX: dropEffect should be updated per |aOperation|.
+    // As things stand though, |aOperation| isn't well handled within "our"
+    // events, that is, when the drop happens within the window: it is set
+    // either to NSDragOperationGeneric or to NSDragOperationNone.
+    // For that reason, it's not yet possible to override dropEffect per the
+    // given OS value, and it's also unclear what's the correct dropEffect
+    // value for NSDragOperationGeneric that is passed by other applications.
+    // All that said, NSDragOperationNone is still reliable.
+    if (aOperation == NSDragOperationNone) {
+      RefPtr<dom::DataTransfer> dataTransfer = dragService->GetDataTransfer();
+      if (dataTransfer) {
+        dataTransfer->SetDropEffectInt(nsIDragService::DRAGDROP_ACTION_NONE);
+      }
+    }
+
+    dragService->EndDragSession(true,
+                                nsCocoaUtils::ModifiersForEvent(currentEvent));
+    NS_RELEASE(mDragService);
+  }
+
+  [globalDragPboard release];
+  globalDragPboard = nil;
+  [gLastDragMouseDownEvent release];
+  gLastDragMouseDownEvent = nil;
+  mPerformedDrag = YES;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// NSDraggingSource
+- (void)draggingSession:(NSDraggingSession*)aSession
+           movedToPoint:(NSPoint)aPoint {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Get the drag service if it isn't already cached. The drag service
+  // isn't cached when dragging over a different application.
+  nsCOMPtr<nsIDragService> dragService = mDragService;
+  if (!dragService) {
+    dragService = do_GetService(kDragServiceContractID);
+  }
+
+  if (dragService) {
+    nsDragService* ds = static_cast<nsDragService*>(dragService.get());
+    ds->DragMovedWithView(aSession, aPoint);
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// NSDraggingSource
+- (void)draggingSession:(NSDraggingSession*)aSession
+       willBeginAtPoint:(NSPoint)aPoint {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // there should never be a globalDragPboard when "willBeginAtPoint:" is
+  // called, but just in case we'll take care of it here.
+  [globalDragPboard release];
+
+  // Set the global drag pasteboard that will be used for this drag session.
+  // This will be set back to nil when the drag session ends (mouse exits
+  // the view or a drop happens within the view).
+  globalDragPboard = [[aSession draggingPasteboard] retain];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Get the paste location from the low level pasteboard.
+static CFTypeRefPtr<CFURLRef> GetPasteLocation(NSPasteboard* aPasteboard) {
+  PasteboardRef pboardRef = nullptr;
+  PasteboardCreate((CFStringRef)[aPasteboard name], &pboardRef);
+  if (!pboardRef) {
+    return nullptr;
+  }
+
+  auto pasteBoard = CFTypeRefPtr<PasteboardRef>::WrapUnderCreateRule(pboardRef);
+  PasteboardSynchronize(pasteBoard.get());
+
+  CFURLRef urlRef = nullptr;
+  PasteboardCopyPasteLocation(pasteBoard.get(), &urlRef);
+  return CFTypeRefPtr<CFURLRef>::WrapUnderCreateRule(urlRef);
+}
+
+// NSPasteboardItemDataProvider
+- (void)pasteboard:(NSPasteboard*)aPasteboard
+                  item:(NSPasteboardItem*)aItem
+    provideDataForType:(NSString*)aType {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+#ifdef NIGHTLY_BUILD
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+#endif
+
+  if (!gDraggedTransferables) {
+    return;
+  }
+
+  uint32_t count = 0;
+  gDraggedTransferables->GetLength(&count);
+
+  for (uint32_t j = 0; j < count; j++) {
+    nsCOMPtr<nsITransferable> currentTransferable =
+        do_QueryElementAt(gDraggedTransferables, j);
+    if (!currentTransferable) {
+      return;
+    }
+
+    // Transform the transferable to an NSDictionary.
+    NSDictionary* pasteboardOutputDict =
+        nsClipboard::PasteboardDictFromTransferable(currentTransferable);
+    if (!pasteboardOutputDict) {
+      return;
+    }
+
+    // Write everything out to the pasteboard.
+    unsigned int typeCount = [pasteboardOutputDict count];
+    NSMutableArray* types = [NSMutableArray arrayWithCapacity:typeCount + 1];
+    [types addObjectsFromArray:[pasteboardOutputDict allKeys]];
+    [types addObject:[UTIHelper stringFromPboardType:kMozWildcardPboardType]];
+    for (unsigned int k = 0; k < typeCount; k++) {
+      NSString* curType = [types objectAtIndex:k];
+      if ([curType isEqualToString:[UTIHelper stringFromPboardType:
+                                                  NSPasteboardTypeString]] ||
+          [curType
+              isEqualToString:[UTIHelper
+                                  stringFromPboardType:kPublicUrlPboardType]] ||
+          [curType isEqualToString:[UTIHelper stringFromPboardType:
+                                                  kPublicUrlNamePboardType]] ||
+          [curType
+              isEqualToString:[UTIHelper
+                                  stringFromPboardType:(NSString*)
+                                                           kUTTypeFileURL]]) {
+        [aPasteboard setString:[pasteboardOutputDict valueForKey:curType]
+                       forType:curType];
+      } else if ([curType isEqualToString:[UTIHelper
+                                              stringFromPboardType:
+                                                  kUrlsWithTitlesPboardType]]) {
+        [aPasteboard setPropertyList:[pasteboardOutputDict valueForKey:curType]
+                             forType:curType];
+      } else if ([curType
+                     isEqualToString:[UTIHelper stringFromPboardType:
+                                                    NSPasteboardTypeHTML]]) {
+        [aPasteboard setString:(nsClipboard::WrapHtmlForSystemPasteboard(
+                                   [pasteboardOutputDict valueForKey:curType]))
+                       forType:curType];
+      } else if ([curType
+                     isEqualToString:[UTIHelper stringFromPboardType:
+                                                    NSPasteboardTypeTIFF]] ||
+                 [curType isEqualToString:[UTIHelper
+                                              stringFromPboardType:
+                                                  kMozCustomTypesPboardType]]) {
+        [aPasteboard setData:[pasteboardOutputDict valueForKey:curType]
+                     forType:curType];
+      } else if ([curType
+                     isEqualToString:[UTIHelper stringFromPboardType:
+                                                    kMozFileUrlsPboardType]]) {
+        [aPasteboard writeObjects:[pasteboardOutputDict valueForKey:curType]];
+      } else if ([curType
+                     isEqualToString:
+                         [UTIHelper
+                             stringFromPboardType:
+                                 (NSString*)kPasteboardTypeFileURLPromise]]) {
+        nsCOMPtr<nsIFile> targFile;
+        NS_NewLocalFile(u""_ns, true, getter_AddRefs(targFile));
+        nsCOMPtr<nsILocalFileMac> macLocalFile = do_QueryInterface(targFile);
+        if (!macLocalFile) {
+          NS_ERROR("No Mac local file");
+          continue;
+        }
+
+        CFTypeRefPtr<CFURLRef> url = GetPasteLocation(aPasteboard);
+        if (!url) {
+          continue;
+        }
+
+        if (!NS_SUCCEEDED(macLocalFile->InitWithCFURL(url.get()))) {
+          NS_ERROR("failed InitWithCFURL");
+          continue;
+        }
+
+        if (!gDraggedTransferables) {
+          continue;
+        }
+
+        uint32_t transferableCount;
+        nsresult rv = gDraggedTransferables->GetLength(&transferableCount);
+        if (NS_FAILED(rv)) {
+          continue;
+        }
+
+        for (uint32_t i = 0; i < transferableCount; i++) {
+          nsCOMPtr<nsITransferable> item =
+              do_QueryElementAt(gDraggedTransferables, i);
+          if (!item) {
+            NS_ERROR("no transferable");
+            continue;
+          }
+
+          item->SetTransferData(kFilePromiseDirectoryMime, macLocalFile);
+
+          // Now request the kFilePromiseMime data, which will invoke the data
+          // provider. If successful, the file will have been created.
+          nsCOMPtr<nsISupports> fileDataPrimitive;
+          Unused << item->GetTransferData(kFilePromiseMime,
+                                          getter_AddRefs(fileDataPrimitive));
+        }
+
+        [aPasteboard setPropertyList:[pasteboardOutputDict valueForKey:curType]
+                             forType:curType];
+      }
+    }
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+#pragma mark -
+
+// Support for the "Services" menu. We currently only support sending strings
+// and HTML to system services.
+// This method can be called on any thread (see bug 1751687). We can only
+// usefully handle it on the main thread.
+- (id)validRequestorForSendType:(NSString*)sendType
+                     returnType:(NSString*)returnType {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!NS_IsMainThread()) {
+    // We don't have any thread-safe ways of checking whether we can send
+    // or receive content. Just say no. In normal cases, we expect this
+    // method to be called on the main thread.
+    return [super validRequestorForSendType:sendType returnType:returnType];
+  }
+
+  // sendType contains the type of data that the service would like this
+  // application to send to it.  sendType is nil if the service is not
+  // requesting any data.
+  //
+  // returnType contains the type of data the the service would like to
+  // return to this application (e.g., to overwrite the selection).
+  // returnType is nil if the service will not return any data.
+  //
+  // The following condition thus triggers when the service expects a string
+  // or HTML from us or no data at all AND when the service will either not
+  // send back any data to us or will send a string or HTML back to us.
+
+  id result = nil;
+
+  NSString* stringType =
+      [UTIHelper stringFromPboardType:NSPasteboardTypeString];
+  NSString* htmlType = [UTIHelper stringFromPboardType:NSPasteboardTypeHTML];
+  if ((!sendType || [sendType isEqualToString:stringType] ||
+       [sendType isEqualToString:htmlType]) &&
+      (!returnType || [returnType isEqualToString:stringType] ||
+       [returnType isEqualToString:htmlType])) {
+    if (mGeckoChild) {
+      // Assume that this object will be able to handle this request.
+      result = self;
+
+      // Keep the ChildView alive during this operation.
+      nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+      if (sendType) {
+        // Determine if there is a current selection (chrome/content).
+        if (!nsClipboard::sSelectionCache) {
+          result = nil;
+        }
+      }
+
+      // Determine if we can paste (if receiving data from the service).
+      if (mGeckoChild && returnType) {
+        WidgetContentCommandEvent command(
+            true, eContentCommandPasteTransferable, mGeckoChild, true);
+        // This might possibly destroy our widget (and null out mGeckoChild).
+        mGeckoChild->DispatchWindowEvent(command);
+        if (!mGeckoChild || !command.mSucceeded || !command.mIsEnabled)
+          result = nil;
+      }
+    }
+  }
+
+  // Give the superclass a chance if this object will not handle this request.
+  if (!result)
+    result = [super validRequestorForSendType:sendType returnType:returnType];
+
+  return result;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (BOOL)writeSelectionToPasteboard:(NSPasteboard*)pboard types:(NSArray*)types {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+
+  // Make sure that the service will accept strings or HTML.
+  if (![types
+          containsObject:[UTIHelper stringFromPboardType:NSStringPboardType]] &&
+      ![types
+          containsObject:[UTIHelper
+                             stringFromPboardType:NSPasteboardTypeString]] &&
+      ![types containsObject:[UTIHelper
+                                 stringFromPboardType:NSPasteboardTypeHTML]]) {
+    return NO;
+  }
+
+  // Bail out if there is no Gecko object.
+  if (!mGeckoChild) return NO;
+
+  // Transform the transferable to an NSDictionary.
+  NSDictionary* pasteboardOutputDict = nullptr;
+
+  pasteboardOutputDict =
+      nsClipboard::PasteboardDictFromTransferable(nsClipboard::sSelectionCache);
+
+  if (!pasteboardOutputDict) return NO;
+
+  // Declare the pasteboard types.
+  unsigned int typeCount = [pasteboardOutputDict count];
+  NSMutableArray* declaredTypes = [NSMutableArray arrayWithCapacity:typeCount];
+  [declaredTypes addObjectsFromArray:[pasteboardOutputDict allKeys]];
+  [pboard declareTypes:declaredTypes owner:nil];
+
+  // Write the data to the pasteboard.
+  for (unsigned int i = 0; i < typeCount; i++) {
+    NSString* currentKey = [declaredTypes objectAtIndex:i];
+    id currentValue = [pasteboardOutputDict valueForKey:currentKey];
+
+    if ([currentKey
+            isEqualToString:[UTIHelper
+                                stringFromPboardType:NSPasteboardTypeString]] ||
+        [currentKey
+            isEqualToString:[UTIHelper
+                                stringFromPboardType:kPublicUrlPboardType]] ||
+        [currentKey isEqualToString:[UTIHelper stringFromPboardType:
+                                                   kPublicUrlNamePboardType]]) {
+      [pboard setString:currentValue forType:currentKey];
+    } else if ([currentKey
+                   isEqualToString:
+                       [UTIHelper stringFromPboardType:NSPasteboardTypeHTML]]) {
+      [pboard setString:(nsClipboard::WrapHtmlForSystemPasteboard(currentValue))
+                forType:currentKey];
+    } else if ([currentKey
+                   isEqualToString:
+                       [UTIHelper stringFromPboardType:NSPasteboardTypeTIFF]]) {
+      [pboard setData:currentValue forType:currentKey];
+    } else if ([currentKey
+                   isEqualToString:
+                       [UTIHelper
+                           stringFromPboardType:
+                               (NSString*)kPasteboardTypeFileURLPromise]] ||
+               [currentKey
+                   isEqualToString:[UTIHelper stringFromPboardType:
+                                                  kUrlsWithTitlesPboardType]]) {
+      [pboard setPropertyList:currentValue forType:currentKey];
+    }
+  }
+  return YES;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NO);
+}
+
+// Called if the service wants us to replace the current selection.
+- (BOOL)readSelectionFromPasteboard:(NSPasteboard*)pboard {
+  nsresult rv;
+  nsCOMPtr<nsITransferable> trans =
+      do_CreateInstance("@mozilla.org/widget/transferable;1", &rv);
+  if (NS_FAILED(rv)) return NO;
+  trans->Init(nullptr);
+
+  trans->AddDataFlavor(kTextMime);
+  trans->AddDataFlavor(kHTMLMime);
+
+  rv = nsClipboard::TransferableFromPasteboard(trans, pboard);
+  if (NS_FAILED(rv)) return NO;
+
+  NS_ENSURE_TRUE(mGeckoChild, false);
+
+  WidgetContentCommandEvent command(true, eContentCommandPasteTransferable,
+                                    mGeckoChild);
+  command.mTransferable = trans;
+  mGeckoChild->DispatchWindowEvent(command);
+
+  return command.mSucceeded && command.mIsEnabled;
+}
+
+- (void)pressureChangeWithEvent:(NSEvent*)event {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK
+
+  NSInteger stage = [event stage];
+  if (mLastPressureStage == 1 && stage == 2) {
+    NSUserDefaults* userDefaults = [NSUserDefaults standardUserDefaults];
+    if ([userDefaults integerForKey:@"com.apple.trackpad.forceClick"] == 1) {
+      // This is no public API to get configuration for current force click.
+      // This is filed as radar 29294285.
+      [self quickLookWithEvent:event];
+    }
+  }
+  mLastPressureStage = stage;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK
+}
+
+nsresult nsChildView::GetSelectionAsPlaintext(nsAString& aResult) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!nsClipboard::sSelectionCache) {
+    MOZ_ASSERT(aResult.IsEmpty());
+    return NS_OK;
+  }
+
+  // Get the current chrome or content selection.
+  NSDictionary* pasteboardOutputDict = nullptr;
+  pasteboardOutputDict =
+      nsClipboard::PasteboardDictFromTransferable(nsClipboard::sSelectionCache);
+
+  if (NS_WARN_IF(!pasteboardOutputDict)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Declare the pasteboard types.
+  unsigned int typeCount = [pasteboardOutputDict count];
+  NSMutableArray* declaredTypes = [NSMutableArray arrayWithCapacity:typeCount];
+  [declaredTypes addObjectsFromArray:[pasteboardOutputDict allKeys]];
+  NSString* currentKey = [declaredTypes objectAtIndex:0];
+  NSString* currentValue = [pasteboardOutputDict valueForKey:currentKey];
+  const char* textSelection = [currentValue UTF8String];
+  aResult = NS_ConvertUTF8toUTF16(textSelection);
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+#ifdef DEBUG
+nsresult nsChildView::SetHiDPIMode(bool aHiDPI) {
+  nsCocoaUtils::InvalidateHiDPIState();
+  Preferences::SetInt("gfx.hidpi.enabled", aHiDPI ? 1 : 0);
+  BackingScaleFactorChanged();
+  return NS_OK;
+}
+
+nsresult nsChildView::RestoreHiDPIMode() {
+  nsCocoaUtils::InvalidateHiDPIState();
+  Preferences::ClearUser("gfx.hidpi.enabled");
+  BackingScaleFactorChanged();
+  return NS_OK;
+}
+#endif
+
+#pragma mark -
+
+#ifdef ACCESSIBILITY
+
+/* Every ChildView has a corresponding mozDocAccessible object that is doing all
+   the heavy lifting. The topmost ChildView corresponds to a mozRootAccessible
+   object.
+
+   All ChildView needs to do is to route all accessibility calls (from the
+   NSAccessibility APIs) down to its object, pretending that they are the same.
+*/
+- (id<mozAccessible>)accessible {
+  if (!mGeckoChild) return nil;
+
+  id<mozAccessible> nativeAccessible = nil;
+
+  nsAutoRetainCocoaObject kungFuDeathGrip(self);
+  RefPtr<nsChildView> geckoChild(mGeckoChild);
+  RefPtr<a11y::LocalAccessible> accessible =
+      geckoChild->GetDocumentAccessible();
+  if (!accessible) return nil;
+
+  accessible->GetNativeInterface((void**)&nativeAccessible);
+
+#  ifdef DEBUG_hakan
+  NSAssert(![nativeAccessible isExpired], @"native acc is expired!!!");
+#  endif
+
+  return nativeAccessible;
+}
+
+/* Implementation of formal mozAccessible formal protocol (enabling mozViews
+   to talk to mozAccessible objects in the accessibility module). */
+
+- (BOOL)hasRepresentedView {
+  return YES;
+}
+
+- (id)representedView {
+  return self;
+}
+
+- (BOOL)isRoot {
+  return [[self accessible] isRoot];
+}
+
+#  pragma mark -
+
+// general
+
+- (BOOL)isAccessibilityElement {
+  if (!mozilla::a11y::ShouldA11yBeEnabled())
+    return [super isAccessibilityElement];
+
+  return [[self accessible] isAccessibilityElement];
+}
+
+- (id)accessibilityHitTest:(NSPoint)point {
+  if (!mozilla::a11y::ShouldA11yBeEnabled())
+    return [super accessibilityHitTest:point];
+
+  return [[self accessible] accessibilityHitTest:point];
+}
+
+- (id)accessibilityFocusedUIElement {
+  if (!mozilla::a11y::ShouldA11yBeEnabled())
+    return [super accessibilityFocusedUIElement];
+
+  return [[self accessible] accessibilityFocusedUIElement];
+}
+
+// actions
+
+- (NSArray*)accessibilityActionNames {
+  if (!mozilla::a11y::ShouldA11yBeEnabled())
+    return [super accessibilityActionNames];
+
+  return [[self accessible] accessibilityActionNames];
+}
+
+- (NSString*)accessibilityActionDescription:(NSString*)action {
+  if (!mozilla::a11y::ShouldA11yBeEnabled())
+    return [super accessibilityActionDescription:action];
+
+  return [[self accessible] accessibilityActionDescription:action];
+}
+
+- (void)accessibilityPerformAction:(NSString*)action {
+  if (!mozilla::a11y::ShouldA11yBeEnabled())
+    return [super accessibilityPerformAction:action];
+
+  return [[self accessible] accessibilityPerformAction:action];
+}
+
+// attributes
+
+- (NSArray*)accessibilityAttributeNames {
+  if (!mozilla::a11y::ShouldA11yBeEnabled())
+    return [super accessibilityAttributeNames];
+
+  return [[self accessible] accessibilityAttributeNames];
+}
+
+- (BOOL)accessibilityIsAttributeSettable:(NSString*)attribute {
+  if (!mozilla::a11y::ShouldA11yBeEnabled())
+    return [super accessibilityIsAttributeSettable:attribute];
+
+  return [[self accessible] accessibilityIsAttributeSettable:attribute];
+}
+
+- (id)accessibilityAttributeValue:(NSString*)attribute {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!mozilla::a11y::ShouldA11yBeEnabled())
+    return [super accessibilityAttributeValue:attribute];
+
+  id<mozAccessible> accessible = [self accessible];
+
+  // if we're the root (topmost) accessible, we need to return our native
+  // AXParent as we traverse outside to the hierarchy of whoever embeds us.
+  // thus, fall back on NSView's default implementation for this attribute.
+  if ([attribute isEqualToString:NSAccessibilityParentAttribute] &&
+      [accessible isRoot]) {
+    id parentAccessible = [super accessibilityAttributeValue:attribute];
+    return parentAccessible;
+  }
+
+  return [accessible accessibilityAttributeValue:attribute];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+#endif /* ACCESSIBILITY */
+
++ (uint32_t)sUniqueKeyEventId {
+  return sUniqueKeyEventId;
+}
+
++ (NSMutableDictionary*)sNativeKeyEventsMap {
+  // This dictionary is "leaked".
+  static NSMutableDictionary* sNativeKeyEventsMap =
+      [[NSMutableDictionary alloc] init];
+  return sNativeKeyEventsMap;
+}
+
+@end
+
+@implementation PixelHostingView
+
+- (id)initWithFrame:(NSRect)aRect {
+  self = [super initWithFrame:aRect];
+
+  self.wantsLayer = YES;
+  self.layerContentsRedrawPolicy = NSViewLayerContentsRedrawDuringViewResize;
+
+  return self;
+}
+
+- (BOOL)isFlipped {
+  return YES;
+}
+
+- (NSView*)hitTest:(NSPoint)aPoint {
+  return nil;
+}
+
+- (void)drawRect:(NSRect)aRect {
+  NS_WARNING("Unexpected call to drawRect: This view returns YES from "
+             "wantsUpdateLayer, so "
+             "drawRect should not be called.");
+}
+
+- (BOOL)wantsUpdateLayer {
+  return YES;
+}
+
+- (void)updateLayer {
+  [(ChildView*)[self superview] updateRootCALayer];
+}
+
+- (BOOL)wantsBestResolutionOpenGLSurface {
+  return nsCocoaUtils::HiDPIEnabled() ? YES : NO;
+}
+
+@end
+
+#pragma mark -
+
+void ChildViewMouseTracker::OnDestroyView(ChildView* aView) {
+  if (sLastMouseEventView == aView) {
+    sLastMouseEventView = nil;
+    [sLastMouseMoveEvent release];
+    sLastMouseMoveEvent = nil;
+  }
+}
+
+void ChildViewMouseTracker::OnDestroyWindow(NSWindow* aWindow) {
+  if (sWindowUnderMouse == aWindow) {
+    sWindowUnderMouse = nil;
+  }
+}
+
+void ChildViewMouseTracker::MouseEnteredWindow(NSEvent* aEvent) {
+  NSWindow* window = aEvent.window;
+  if (!window.ignoresMouseEvents) {
+    sWindowUnderMouse = window;
+    ReEvaluateMouseEnterState(aEvent);
+  }
+}
+
+void ChildViewMouseTracker::MouseExitedWindow(NSEvent* aEvent) {
+  if (sWindowUnderMouse == aEvent.window) {
+    sWindowUnderMouse = nil;
+    [sLastMouseMoveEvent release];
+    sLastMouseMoveEvent = nil;
+    ReEvaluateMouseEnterState(aEvent);
+  }
+}
+
+void ChildViewMouseTracker::NativeMenuOpened() {
+  // Send a mouse exit event now.
+  // The menu consumes all mouse events while it's open, and we don't want to be
+  // stuck thinking the mouse is still hovering our window after the mouse has
+  // already moved. This could result in unintended cursor changes or tooltips.
+  sWindowUnderMouse = nil;
+  ReEvaluateMouseEnterState(nil);
+}
+
+void ChildViewMouseTracker::NativeMenuClosed() {
+  // If a window was hovered before the menu opened, re-enter that window at the
+  // last known mouse position. After -[NSView didCloseMenu:withEvent:] is
+  // called, any NSTrackingArea updates that were buffered while the menu was
+  // open will be replayed.
+  if (sLastMouseMoveEvent) {
+    sWindowUnderMouse = sLastMouseMoveEvent.window;
+    ReEvaluateMouseEnterState(sLastMouseMoveEvent);
+  }
+}
+
+void ChildViewMouseTracker::ReEvaluateMouseEnterState(NSEvent* aEvent,
+                                                      ChildView* aOldView) {
+  ChildView* oldView = aOldView ? aOldView : sLastMouseEventView;
+  sLastMouseEventView = ViewForEvent(aEvent);
+  if (sLastMouseEventView != oldView) {
+    // Send enter and / or exit events.
+    WidgetMouseEvent::ExitFrom exitFrom =
+        [sLastMouseEventView window] == [oldView window]
+            ? WidgetMouseEvent::ePlatformChild
+            : WidgetMouseEvent::ePlatformTopLevel;
+    [oldView sendMouseEnterOrExitEvent:aEvent enter:NO exitFrom:exitFrom];
+    // After the cursor exits the window set it to a visible regular arrow
+    // cursor.
+    if (exitFrom == WidgetMouseEvent::ePlatformTopLevel) {
+      [[nsCursorManager sharedInstance]
+          setNonCustomCursor:nsIWidget::Cursor{eCursor_standard}];
+    }
+    [sLastMouseEventView sendMouseEnterOrExitEvent:aEvent
+                                             enter:YES
+                                          exitFrom:exitFrom];
+  }
+}
+
+void ChildViewMouseTracker::ResendLastMouseMoveEvent() {
+  if (sLastMouseMoveEvent) {
+    MouseMoved(sLastMouseMoveEvent);
+  }
+}
+
+void ChildViewMouseTracker::MouseMoved(NSEvent* aEvent) {
+  MouseEnteredWindow(aEvent);
+  [sLastMouseEventView handleMouseMoved:aEvent];
+  if (sLastMouseMoveEvent != aEvent) {
+    [sLastMouseMoveEvent release];
+    sLastMouseMoveEvent = [aEvent retain];
+  }
+}
+
+void ChildViewMouseTracker::MouseScrolled(NSEvent* aEvent) {
+  if (!nsCocoaUtils::IsMomentumScrollEvent(aEvent)) {
+    // Store the position so we can pin future momentum scroll events.
+    sLastScrollEventScreenLocation =
+        nsCocoaUtils::ScreenLocationForEvent(aEvent);
+  }
+}
+
+ChildView* ChildViewMouseTracker::ViewForEvent(NSEvent* aEvent) {
+  NSWindow* window = sWindowUnderMouse;
+  if (!window) return nil;
+
+  NSPoint windowEventLocation =
+      nsCocoaUtils::EventLocationForWindow(aEvent, window);
+  NSView* view = [[[window contentView] superview] hitTest:windowEventLocation];
+
+  if (![view isKindOfClass:[ChildView class]]) return nil;
+
+  ChildView* childView = (ChildView*)view;
+  // If childView is being destroyed return nil.
+  if (![childView widget]) return nil;
+  return WindowAcceptsEvent(window, aEvent, childView) ? childView : nil;
+}
+
+BOOL ChildViewMouseTracker::WindowAcceptsEvent(NSWindow* aWindow,
+                                               NSEvent* aEvent,
+                                               ChildView* aView,
+                                               BOOL aIsClickThrough) {
+  // Right mouse down events may get through to all windows, even to a top level
+  // window with an open sheet.
+  if (!aWindow || [aEvent type] == NSEventTypeRightMouseDown) return YES;
+
+  id delegate = [aWindow delegate];
+  if (!delegate || ![delegate isKindOfClass:[WindowDelegate class]]) return YES;
+
+  nsIWidget* windowWidget = [(WindowDelegate*)delegate geckoWidget];
+  if (!windowWidget) return YES;
+
+  NSWindow* topLevelWindow = nil;
+
+  switch (windowWidget->GetWindowType()) {
+    case WindowType::Popup:
+      // If this is a context menu, it won't have a parent. So we'll always
+      // accept mouse move events on context menus even when none of our windows
+      // is active, which is the right thing to do.
+      // For panels, the parent window is the XUL window that owns the panel.
+      return WindowAcceptsEvent([aWindow parentWindow], aEvent, aView,
+                                aIsClickThrough);
+
+    case WindowType::TopLevel:
+    case WindowType::Dialog:
+      if ([aWindow attachedSheet]) return NO;
+
+      topLevelWindow = aWindow;
+      break;
+    case WindowType::Sheet: {
+      nsIWidget* parentWidget = windowWidget->GetSheetWindowParent();
+      if (!parentWidget) return YES;
+
+      topLevelWindow = (NSWindow*)parentWidget->GetNativeData(NS_NATIVE_WINDOW);
+      break;
+    }
+
+    default:
+      return YES;
+  }
+
+  if (!topLevelWindow || ([topLevelWindow isMainWindow] && !aIsClickThrough) ||
+      [aEvent type] == NSEventTypeOtherMouseDown ||
+      (([aEvent modifierFlags] & NSEventModifierFlagCommand) != 0 &&
+       [aEvent type] != NSEventTypeMouseMoved))
+    return YES;
+
+  // If we're here then we're dealing with a left click or mouse move on an
+  // inactive window or something similar. Ask Gecko what to do.
+  return [aView inactiveWindowAcceptsMouseEvent:aEvent];
+}
+
+#pragma mark -
diff --git a/widget/cocoa/nsClipboard.h b/widget/cocoa/nsClipboard.h
new file mode 100644
index 0000000000..a9d5e79d96
--- /dev/null
+++ b/widget/cocoa/nsClipboard.h
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsClipboard_h_
+#define nsClipboard_h_
+
+#include "nsBaseClipboard.h"
+#include "nsCOMPtr.h"
+#include "nsIClipboard.h"
+#include "nsString.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/StaticPtr.h"
+
+#import <Cocoa/Cocoa.h>
+
+class nsITransferable;
+
+class nsClipboard : public nsBaseClipboard {
+ public:
+  nsClipboard();
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // On macOS, cache the transferable of the current selection (chrome/content)
+  // in the parent process. This is needed for the services menu which
+  // requires synchronous access to the current selection.
+  static mozilla::StaticRefPtr<nsITransferable> sSelectionCache;
+  static int32_t sSelectionCacheChangeCount;
+
+  // Helper methods, used also by nsDragService
+  static NSDictionary* PasteboardDictFromTransferable(
+      nsITransferable* aTransferable);
+  // aPasteboardType is being retained and needs to be released by the caller.
+  static bool IsStringType(const nsCString& aMIMEType,
+                           NSString** aPasteboardType);
+  static bool IsImageType(const nsACString& aMIMEType);
+  static NSString* WrapHtmlForSystemPasteboard(NSString* aString);
+  static nsresult TransferableFromPasteboard(nsITransferable* aTransferable,
+                                             NSPasteboard* pboard);
+
+ protected:
+  // Implement the native clipboard behavior.
+  NS_IMETHOD SetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) override;
+  NS_IMETHOD GetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) override;
+  nsresult EmptyNativeClipboardData(int32_t aWhichClipboard) override;
+  mozilla::Result<int32_t, nsresult> GetNativeClipboardSequenceNumber(
+      int32_t aWhichClipboard) override;
+  mozilla::Result<bool, nsresult> HasNativeClipboardDataMatchingFlavors(
+      const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) override;
+
+  void ClearSelectionCache();
+  void SetSelectionCache(nsITransferable* aTransferable);
+
+ private:
+  virtual ~nsClipboard();
+
+  static mozilla::Maybe<uint32_t> FindIndexOfImageFlavor(
+      const nsTArray<nsCString>& aMIMETypes);
+};
+
+#endif  // nsClipboard_h_
diff --git a/widget/cocoa/nsClipboard.mm b/widget/cocoa/nsClipboard.mm
new file mode 100644
index 0000000000..ba747e5b27
--- /dev/null
+++ b/widget/cocoa/nsClipboard.mm
@@ -0,0 +1,875 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <algorithm>
+
+#include "mozilla/gfx/2D.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Unused.h"
+
+#include "gfxPlatform.h"
+#include "nsArrayUtils.h"
+#include "nsCOMPtr.h"
+#include "nsClipboard.h"
+#include "nsString.h"
+#include "nsISupportsPrimitives.h"
+#include "nsPrimitiveHelpers.h"
+#include "nsIFile.h"
+#include "nsStringStream.h"
+#include "nsEscape.h"
+#include "nsPrintfCString.h"
+#include "nsObjCExceptions.h"
+#include "imgIContainer.h"
+#include "nsCocoaUtils.h"
+
+using mozilla::gfx::DataSourceSurface;
+using mozilla::gfx::SourceSurface;
+
+mozilla::StaticRefPtr<nsITransferable> nsClipboard::sSelectionCache;
+int32_t nsClipboard::sSelectionCacheChangeCount = 0;
+
+nsClipboard::nsClipboard()
+    : nsBaseClipboard(mozilla::dom::ClipboardCapabilities(
+          false /* supportsSelectionClipboard */,
+          true /* supportsFindClipboard */,
+          true /* supportsSelectionCache */)) {}
+
+nsClipboard::~nsClipboard() { ClearSelectionCache(); }
+
+NS_IMPL_ISUPPORTS_INHERITED0(nsClipboard, nsBaseClipboard)
+
+namespace {
+
+// We separate this into its own function because after an @try, all local
+// variables within that function get marked as volatile, and our C++ type
+// system doesn't like volatile things.
+static NSData* GetDataFromPasteboard(NSPasteboard* aPasteboard,
+                                     NSString* aType) {
+  NSData* data = nil;
+  @try {
+    data = [aPasteboard dataForType:aType];
+  } @catch (NSException* e) {
+    NS_WARNING(nsPrintfCString("Exception raised while getting data from the "
+                               "pasteboard: \"%s - %s\"",
+                               [[e name] UTF8String], [[e reason] UTF8String])
+                   .get());
+    mozilla::Unused << e;
+  }
+  return data;
+}
+
+static NSPasteboard* GetPasteboard(int32_t aWhichClipboard) {
+  switch (aWhichClipboard) {
+    case nsIClipboard::kGlobalClipboard:
+      return [NSPasteboard generalPasteboard];
+    case nsIClipboard::kFindClipboard:
+      return [NSPasteboard pasteboardWithName:NSPasteboardNameFind];
+    default:
+      return nil;
+  }
+}
+
+}  // namespace
+
+void nsClipboard::SetSelectionCache(nsITransferable* aTransferable) {
+  sSelectionCacheChangeCount++;
+  sSelectionCache = aTransferable;
+}
+
+void nsClipboard::ClearSelectionCache() { SetSelectionCache(nullptr); }
+
+NS_IMETHODIMP
+nsClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_ASSERT(aTransferable);
+  MOZ_ASSERT(nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  if (aWhichClipboard == kSelectionCache) {
+    SetSelectionCache(aTransferable);
+    return NS_OK;
+  }
+
+  NSDictionary* pasteboardOutputDict =
+      PasteboardDictFromTransferable(aTransferable);
+  if (!pasteboardOutputDict) return NS_ERROR_FAILURE;
+
+  unsigned int outputCount = [pasteboardOutputDict count];
+  NSArray* outputKeys = [pasteboardOutputDict allKeys];
+  NSPasteboard* cocoaPasteboard = GetPasteboard(aWhichClipboard);
+  MOZ_ASSERT(cocoaPasteboard);
+  if (aWhichClipboard == kFindClipboard) {
+    NSString* stringType =
+        [UTIHelper stringFromPboardType:NSPasteboardTypeString];
+    [cocoaPasteboard declareTypes:[NSArray arrayWithObject:stringType]
+                            owner:nil];
+  } else {
+    // Write everything else out to the general pasteboard.
+    MOZ_ASSERT(aWhichClipboard == kGlobalClipboard);
+    [cocoaPasteboard declareTypes:outputKeys owner:nil];
+  }
+
+  for (unsigned int i = 0; i < outputCount; i++) {
+    NSString* currentKey = [outputKeys objectAtIndex:i];
+    id currentValue = [pasteboardOutputDict valueForKey:currentKey];
+    if (aWhichClipboard == kFindClipboard) {
+      if ([currentKey isEqualToString:[UTIHelper stringFromPboardType:
+                                                     NSPasteboardTypeString]]) {
+        [cocoaPasteboard setString:currentValue forType:currentKey];
+      }
+    } else {
+      if ([currentKey isEqualToString:[UTIHelper stringFromPboardType:
+                                                     NSPasteboardTypeString]] ||
+          [currentKey
+              isEqualToString:[UTIHelper
+                                  stringFromPboardType:kPublicUrlPboardType]] ||
+          [currentKey
+              isEqualToString:
+                  [UTIHelper stringFromPboardType:kPublicUrlNamePboardType]]) {
+        [cocoaPasteboard setString:currentValue forType:currentKey];
+      } else if ([currentKey
+                     isEqualToString:
+                         [UTIHelper
+                             stringFromPboardType:kUrlsWithTitlesPboardType]]) {
+        [cocoaPasteboard
+            setPropertyList:[pasteboardOutputDict valueForKey:currentKey]
+                    forType:currentKey];
+      } else if ([currentKey
+                     isEqualToString:[UTIHelper stringFromPboardType:
+                                                    NSPasteboardTypeHTML]]) {
+        [cocoaPasteboard
+            setString:(nsClipboard::WrapHtmlForSystemPasteboard(currentValue))
+              forType:currentKey];
+      } else if ([currentKey
+                     isEqualToString:[UTIHelper stringFromPboardType:
+                                                    kMozFileUrlsPboardType]]) {
+        [cocoaPasteboard writeObjects:currentValue];
+      } else if ([currentKey
+                     isEqualToString:
+                         [UTIHelper
+                             stringFromPboardType:(NSString*)kUTTypeFileURL]]) {
+        [cocoaPasteboard setString:currentValue forType:currentKey];
+      } else if ([currentKey
+                     isEqualToString:
+                         [UTIHelper
+                             stringFromPboardType:kPasteboardConcealedType]]) {
+        // It's fine to set the data to null for this field - this field is an
+        // addition to a value's other type and works like a flag.
+        [cocoaPasteboard setData:NULL forType:currentKey];
+      } else {
+        [cocoaPasteboard setData:currentValue forType:currentKey];
+      }
+    }
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+nsresult nsClipboard::TransferableFromPasteboard(
+    nsITransferable* aTransferable, NSPasteboard* cocoaPasteboard) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // get flavor list that includes all acceptable flavors (including ones
+  // obtained through conversion)
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanImport(flavors);
+  if (NS_FAILED(rv)) return NS_ERROR_FAILURE;
+
+  for (uint32_t i = 0; i < flavors.Length(); i++) {
+    nsCString& flavorStr = flavors[i];
+
+    // printf("looking for clipboard data of type %s\n", flavorStr.get());
+
+    NSString* pboardType = nil;
+    if (nsClipboard::IsStringType(flavorStr, &pboardType)) {
+      NSString* pString = [cocoaPasteboard stringForType:pboardType];
+      if (!pString) {
+        continue;
+      }
+
+      NSData* stringData;
+      bool isRTF = [pboardType
+          isEqualToString:[UTIHelper stringFromPboardType:NSPasteboardTypeRTF]];
+      if (isRTF) {
+        stringData = [pString dataUsingEncoding:NSASCIIStringEncoding];
+      } else {
+        stringData = [pString dataUsingEncoding:NSUnicodeStringEncoding];
+      }
+      unsigned int dataLength = [stringData length];
+      void* clipboardDataPtr = malloc(dataLength);
+      if (!clipboardDataPtr) {
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+      [stringData getBytes:clipboardDataPtr length:dataLength];
+
+      // The DOM only wants LF, so convert from MacOS line endings to DOM line
+      // endings.
+      int32_t signedDataLength = dataLength;
+      nsLinebreakHelpers::ConvertPlatformToDOMLinebreaks(
+          isRTF, &clipboardDataPtr, &signedDataLength);
+      dataLength = signedDataLength;
+
+      // skip BOM (Byte Order Mark to distinguish little or big endian)
+      char16_t* clipboardDataPtrNoBOM = (char16_t*)clipboardDataPtr;
+      if ((dataLength > 2) && ((clipboardDataPtrNoBOM[0] == 0xFEFF) ||
+                               (clipboardDataPtrNoBOM[0] == 0xFFFE))) {
+        dataLength -= sizeof(char16_t);
+        clipboardDataPtrNoBOM += 1;
+      }
+
+      nsCOMPtr<nsISupports> genericDataWrapper;
+      nsPrimitiveHelpers::CreatePrimitiveForData(
+          flavorStr, clipboardDataPtrNoBOM, dataLength,
+          getter_AddRefs(genericDataWrapper));
+      aTransferable->SetTransferData(flavorStr.get(), genericDataWrapper);
+      free(clipboardDataPtr);
+      break;
+    } else if (flavorStr.EqualsLiteral(kFileMime)) {
+      NSArray* items = [cocoaPasteboard pasteboardItems];
+      if (!items || [items count] <= 0) {
+        continue;
+      }
+
+      // XXX we don't support multiple clipboard item on DOM and XPCOM interface
+      // for now, so we only get the data from the first pasteboard item.
+      NSPasteboardItem* item = [items objectAtIndex:0];
+      if (!item) {
+        continue;
+      }
+
+      nsCocoaUtils::SetTransferDataForTypeFromPasteboardItem(aTransferable,
+                                                             flavorStr, item);
+    } else if (flavorStr.EqualsLiteral(kCustomTypesMime)) {
+      NSString* type = [cocoaPasteboard
+          availableTypeFromArray:
+              [NSArray
+                  arrayWithObject:[UTIHelper stringFromPboardType:
+                                                 kMozCustomTypesPboardType]]];
+      if (!type) {
+        continue;
+      }
+
+      NSData* pasteboardData = GetDataFromPasteboard(cocoaPasteboard, type);
+      if (!pasteboardData) {
+        continue;
+      }
+
+      unsigned int dataLength = [pasteboardData length];
+      void* clipboardDataPtr = malloc(dataLength);
+      if (!clipboardDataPtr) {
+        return NS_ERROR_OUT_OF_MEMORY;
+      }
+      [pasteboardData getBytes:clipboardDataPtr length:dataLength];
+
+      nsCOMPtr<nsISupports> genericDataWrapper;
+      nsPrimitiveHelpers::CreatePrimitiveForData(
+          flavorStr, clipboardDataPtr, dataLength,
+          getter_AddRefs(genericDataWrapper));
+
+      aTransferable->SetTransferData(flavorStr.get(), genericDataWrapper);
+      free(clipboardDataPtr);
+    } else if (flavorStr.EqualsLiteral(kJPEGImageMime) ||
+               flavorStr.EqualsLiteral(kJPGImageMime) ||
+               flavorStr.EqualsLiteral(kPNGImageMime) ||
+               flavorStr.EqualsLiteral(kGIFImageMime)) {
+      // Figure out if there's data on the pasteboard we can grab (sanity check)
+      NSString* type = [cocoaPasteboard
+          availableTypeFromArray:
+              [NSArray
+                  arrayWithObjects:
+                      [UTIHelper
+                          stringFromPboardType:(NSString*)kUTTypeFileURL],
+                      [UTIHelper stringFromPboardType:NSPasteboardTypeTIFF],
+                      [UTIHelper stringFromPboardType:NSPasteboardTypePNG],
+                      nil]];
+      if (!type) continue;
+
+      // Read data off the clipboard
+      NSData* pasteboardData = GetDataFromPasteboard(cocoaPasteboard, type);
+      if (!pasteboardData) continue;
+
+      // Figure out what type we're converting to
+      CFStringRef outputType = NULL;
+      if (flavorStr.EqualsLiteral(kJPEGImageMime) ||
+          flavorStr.EqualsLiteral(kJPGImageMime))
+        outputType = CFSTR("public.jpeg");
+      else if (flavorStr.EqualsLiteral(kPNGImageMime))
+        outputType = CFSTR("public.png");
+      else if (flavorStr.EqualsLiteral(kGIFImageMime))
+        outputType = CFSTR("com.compuserve.gif");
+      else
+        continue;
+
+      // Use ImageIO to interpret the data on the clipboard and transcode.
+      // Note that ImageIO, like all CF APIs, allows NULLs to propagate freely
+      // and safely in most cases (like ObjC). A notable exception is CFRelease.
+      NSDictionary* options = [NSDictionary
+          dictionaryWithObjectsAndKeys:(NSNumber*)kCFBooleanTrue,
+                                       kCGImageSourceShouldAllowFloat, type,
+                                       kCGImageSourceTypeIdentifierHint, nil];
+      CGImageSourceRef source = nullptr;
+      if (type == [UTIHelper stringFromPboardType:(NSString*)kUTTypeFileURL]) {
+        NSString* urlStr = [cocoaPasteboard stringForType:type];
+        NSURL* url = [NSURL URLWithString:urlStr];
+        source =
+            CGImageSourceCreateWithURL((CFURLRef)url, (CFDictionaryRef)options);
+      } else {
+        source = CGImageSourceCreateWithData((CFDataRef)pasteboardData,
+                                             (CFDictionaryRef)options);
+      }
+
+      NSMutableData* encodedData = [NSMutableData data];
+      CGImageDestinationRef dest = CGImageDestinationCreateWithData(
+          (CFMutableDataRef)encodedData, outputType, 1, NULL);
+      CGImageDestinationAddImageFromSource(dest, source, 0, NULL);
+      bool successfullyConverted = CGImageDestinationFinalize(dest);
+
+      if (successfullyConverted) {
+        // Put the converted data in a form Gecko can understand
+        nsCOMPtr<nsIInputStream> byteStream;
+        NS_NewByteInputStream(getter_AddRefs(byteStream),
+                              mozilla::Span((const char*)[encodedData bytes],
+                                            [encodedData length]),
+                              NS_ASSIGNMENT_COPY);
+
+        aTransferable->SetTransferData(flavorStr.get(), byteStream);
+      }
+
+      if (dest) CFRelease(dest);
+      if (source) CFRelease(source);
+
+      if (successfullyConverted) {
+        // XXX Maybe try to fill in more types? Is there a point?
+        break;
+      } else {
+        continue;
+      }
+    }
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  if (kSelectionCache == aWhichClipboard) {
+    if (!sSelectionCache) {
+      return NS_OK;
+    }
+
+    // get flavor list that includes all acceptable flavors (including ones
+    // obtained through conversion)
+    nsTArray<nsCString> flavors;
+    nsresult rv = aTransferable->FlavorsTransferableCanImport(flavors);
+    if (NS_FAILED(rv)) {
+      return NS_ERROR_FAILURE;
+    }
+
+    for (const auto& flavor : flavors) {
+      nsCOMPtr<nsISupports> dataSupports;
+      rv = sSelectionCache->GetTransferData(flavor.get(),
+                                            getter_AddRefs(dataSupports));
+      if (NS_SUCCEEDED(rv)) {
+        MOZ_CLIPBOARD_LOG("%s: getting %s from cache.", __FUNCTION__,
+                          flavor.get());
+        aTransferable->SetTransferData(flavor.get(), dataSupports);
+        // XXX Maybe try to fill in more types? Is there a point?
+        break;
+      }
+    }
+    return NS_OK;
+  }
+
+  NSPasteboard* cocoaPasteboard = GetPasteboard(aWhichClipboard);
+  if (!cocoaPasteboard) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return TransferableFromPasteboard(aTransferable, cocoaPasteboard);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+// returns true if we have *any* of the passed in flavors available for pasting
+mozilla::Result<bool, nsresult>
+nsClipboard::HasNativeClipboardDataMatchingFlavors(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  if (kSelectionCache == aWhichClipboard) {
+    nsTArray<nsCString> transferableFlavors;
+    if (sSelectionCache &&
+        NS_SUCCEEDED(sSelectionCache->FlavorsTransferableCanExport(
+            transferableFlavors))) {
+      if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+        MOZ_CLIPBOARD_LOG("    SelectionCache types (nums %zu)\n",
+                          transferableFlavors.Length());
+        for (const auto& transferableFlavor : transferableFlavors) {
+          MOZ_CLIPBOARD_LOG("        MIME %s", transferableFlavor.get());
+        }
+      }
+
+      for (const auto& transferableFlavor : transferableFlavors) {
+        for (const auto& flavor : aFlavorList) {
+          if (transferableFlavor.Equals(flavor)) {
+            MOZ_CLIPBOARD_LOG("    has %s", flavor.get());
+            return true;
+          }
+        }
+      }
+    }
+
+    if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+      MOZ_CLIPBOARD_LOG("    no targets at clipboard (bad match)\n");
+    }
+
+    return false;
+  }
+
+  NSPasteboard* cocoaPasteboard = GetPasteboard(aWhichClipboard);
+  MOZ_ASSERT(cocoaPasteboard);
+  if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+    NSArray* types = [cocoaPasteboard types];
+    uint32_t count = [types count];
+    MOZ_CLIPBOARD_LOG("    Pasteboard types (nums %d)\n", count);
+    for (uint32_t i = 0; i < count; i++) {
+      NSPasteboardType type = [types objectAtIndex:i];
+      if (!type) {
+        MOZ_CLIPBOARD_LOG("        failed to get MIME\n");
+        continue;
+      }
+      MOZ_CLIPBOARD_LOG("        MIME %s\n", [type UTF8String]);
+    }
+  }
+
+  for (auto& mimeType : aFlavorList) {
+    NSString* pboardType = nil;
+    if (nsClipboard::IsStringType(mimeType, &pboardType)) {
+      NSString* availableType = [cocoaPasteboard
+          availableTypeFromArray:[NSArray arrayWithObject:pboardType]];
+      if (availableType && [availableType isEqualToString:pboardType]) {
+        MOZ_CLIPBOARD_LOG("    has %s\n", mimeType.get());
+        return true;
+      }
+    } else if (mimeType.EqualsLiteral(kCustomTypesMime)) {
+      NSString* availableType = [cocoaPasteboard
+          availableTypeFromArray:
+              [NSArray
+                  arrayWithObject:[UTIHelper stringFromPboardType:
+                                                 kMozCustomTypesPboardType]]];
+      if (availableType) {
+        MOZ_CLIPBOARD_LOG("    has %s\n", mimeType.get());
+        return true;
+      }
+    } else if (mimeType.EqualsLiteral(kJPEGImageMime) ||
+               mimeType.EqualsLiteral(kJPGImageMime) ||
+               mimeType.EqualsLiteral(kPNGImageMime) ||
+               mimeType.EqualsLiteral(kGIFImageMime)) {
+      NSString* availableType = [cocoaPasteboard
+          availableTypeFromArray:
+              [NSArray
+                  arrayWithObjects:
+                      [UTIHelper stringFromPboardType:NSPasteboardTypeTIFF],
+                      [UTIHelper stringFromPboardType:NSPasteboardTypePNG],
+                      nil]];
+      if (availableType) {
+        MOZ_CLIPBOARD_LOG("    has %s\n", mimeType.get());
+        return true;
+      }
+    } else if (mimeType.EqualsLiteral(kFileMime)) {
+      NSArray* items = [cocoaPasteboard pasteboardItems];
+      if (items && [items count] > 0) {
+        // XXX we only check the first pasteboard item as we only get data from
+        // first item in TransferableFromPasteboard for now.
+        if (NSPasteboardItem* item = [items objectAtIndex:0]) {
+          if (NSString *availableType = [item
+                  availableTypeFromArray:
+                      [NSArray
+                          arrayWithObjects:[UTIHelper
+                                               stringFromPboardType:
+                                                   (NSString*)kUTTypeFileURL],
+                                           nil]]) {
+            MOZ_CLIPBOARD_LOG("    has %s\n", mimeType.get());
+            return true;
+          }
+        }
+      }
+    }
+  }
+
+  if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+    MOZ_CLIPBOARD_LOG("    no targets at clipboard (bad match)\n");
+  }
+
+  return false;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(mozilla::Err(NS_ERROR_FAILURE));
+}
+
+// static
+mozilla::Maybe<uint32_t> nsClipboard::FindIndexOfImageFlavor(
+    const nsTArray<nsCString>& aMIMETypes) {
+  for (uint32_t i = 0; i < aMIMETypes.Length(); ++i) {
+    if (nsClipboard::IsImageType(aMIMETypes[i])) {
+      return mozilla::Some(i);
+    }
+  }
+
+  return mozilla::Nothing();
+}
+
+// This function converts anything that other applications might understand into
+// the system format and puts it into a dictionary which it returns. static
+NSDictionary* nsClipboard::PasteboardDictFromTransferable(
+    nsITransferable* aTransferable) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!aTransferable) {
+    return nil;
+  }
+
+  NSMutableDictionary* pasteboardOutputDict = [NSMutableDictionary dictionary];
+
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanExport(flavors);
+  if (NS_FAILED(rv)) {
+    return nil;
+  }
+
+  const mozilla::Maybe<uint32_t> imageFlavorIndex =
+      nsClipboard::FindIndexOfImageFlavor(flavors);
+
+  if (imageFlavorIndex) {
+    // When right-clicking and "Copy Image" is clicked on macOS, some apps
+    // expect the first flavor to be the image flavor. See bug 1689992. For
+    // other apps, the order shouldn't matter.
+    std::swap(*flavors.begin(), flavors[*imageFlavorIndex]);
+  }
+  for (uint32_t i = 0; i < flavors.Length(); i++) {
+    nsCString& flavorStr = flavors[i];
+
+    MOZ_CLIPBOARD_LOG("writing out clipboard data of type %s (%d)\n",
+                      flavorStr.get(), i);
+
+    NSString* pboardType = nil;
+    if (nsClipboard::IsStringType(flavorStr, &pboardType)) {
+      nsCOMPtr<nsISupports> genericDataWrapper;
+      rv = aTransferable->GetTransferData(flavorStr.get(),
+                                          getter_AddRefs(genericDataWrapper));
+      if (NS_FAILED(rv)) {
+        continue;
+      }
+
+      nsAutoString data;
+      if (nsCOMPtr<nsISupportsString> text =
+              do_QueryInterface(genericDataWrapper)) {
+        text->GetData(data);
+      }
+
+      NSString* nativeString;
+      if (!data.IsEmpty()) {
+        nativeString = [NSString stringWithCharacters:(const unichar*)data.get()
+                                               length:data.Length()];
+      } else {
+        nativeString = [NSString string];
+      }
+
+      // be nice to Carbon apps, normalize the receiver's contents using Form C.
+      nativeString = [nativeString precomposedStringWithCanonicalMapping];
+      if (nativeString) {
+        [pasteboardOutputDict setObject:nativeString forKey:pboardType];
+      }
+
+      if (aTransferable->GetIsPrivateData()) {
+        // In the case of password strings, we want to include the key for
+        // concealed type. These will be flagged as private data.
+        [pasteboardOutputDict
+            setObject:nativeString
+               forKey:[UTIHelper
+                          stringFromPboardType:kPasteboardConcealedType]];
+      }
+    } else if (flavorStr.EqualsLiteral(kCustomTypesMime)) {
+      nsCOMPtr<nsISupports> genericDataWrapper;
+      rv = aTransferable->GetTransferData(flavorStr.get(),
+                                          getter_AddRefs(genericDataWrapper));
+      if (NS_FAILED(rv)) {
+        continue;
+      }
+
+      nsAutoCString data;
+      if (nsCOMPtr<nsISupportsCString> text =
+              do_QueryInterface(genericDataWrapper)) {
+        text->GetData(data);
+      }
+
+      if (!data.IsEmpty()) {
+        NSData* nativeData = [NSData dataWithBytes:data.get()
+                                            length:data.Length()];
+        NSString* customType =
+            [UTIHelper stringFromPboardType:kMozCustomTypesPboardType];
+        if (!nativeData) {
+          continue;
+        }
+        [pasteboardOutputDict setObject:nativeData forKey:customType];
+      }
+    } else if (nsClipboard::IsImageType(flavorStr)) {
+      nsCOMPtr<nsISupports> transferSupports;
+      rv = aTransferable->GetTransferData(flavorStr.get(),
+                                          getter_AddRefs(transferSupports));
+      if (NS_FAILED(rv)) {
+        continue;
+      }
+
+      nsCOMPtr<imgIContainer> image(do_QueryInterface(transferSupports));
+      if (!image) {
+        NS_WARNING("Image isn't an imgIContainer in transferable");
+        continue;
+      }
+
+      RefPtr<SourceSurface> surface = image->GetFrame(
+          imgIContainer::FRAME_CURRENT,
+          imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
+      if (!surface) {
+        continue;
+      }
+      CGImageRef imageRef = NULL;
+      rv = nsCocoaUtils::CreateCGImageFromSurface(surface, &imageRef);
+      if (NS_FAILED(rv) || !imageRef) {
+        continue;
+      }
+
+      // Convert the CGImageRef to TIFF and PNG data.
+      CFMutableDataRef tiffData = CFDataCreateMutable(kCFAllocatorDefault, 0);
+      CFMutableDataRef pngData = CFDataCreateMutable(kCFAllocatorDefault, 0);
+      CGImageDestinationRef destRefTIFF = CGImageDestinationCreateWithData(
+          tiffData, CFSTR("public.tiff"), 1, NULL);
+      CGImageDestinationRef destRefPNG = CGImageDestinationCreateWithData(
+          pngData, CFSTR("public.png"), 1, NULL);
+      CGImageDestinationAddImage(destRefTIFF, imageRef, NULL);
+      CGImageDestinationAddImage(destRefPNG, imageRef, NULL);
+      const bool successfullyConvertedTIFF =
+          CGImageDestinationFinalize(destRefTIFF);
+      const bool successfullyConvertedPNG =
+          CGImageDestinationFinalize(destRefPNG);
+
+      CGImageRelease(imageRef);
+      if (destRefTIFF) {
+        CFRelease(destRefTIFF);
+      }
+      if (destRefPNG) {
+        CFRelease(destRefPNG);
+      }
+
+      if (successfullyConvertedTIFF && tiffData) {
+        NSString* tiffType =
+            [UTIHelper stringFromPboardType:NSPasteboardTypeTIFF];
+        [pasteboardOutputDict setObject:(NSMutableData*)tiffData
+                                 forKey:tiffType];
+      }
+      if (successfullyConvertedPNG && pngData) {
+        NSString* pngType =
+            [UTIHelper stringFromPboardType:NSPasteboardTypePNG];
+
+        [pasteboardOutputDict setObject:(NSMutableData*)pngData forKey:pngType];
+      }
+      if (tiffData) {
+        CFRelease(tiffData);
+      }
+      if (pngData) {
+        CFRelease(pngData);
+      }
+    } else if (flavorStr.EqualsLiteral(kFileMime)) {
+      nsCOMPtr<nsISupports> genericFile;
+      rv = aTransferable->GetTransferData(flavorStr.get(),
+                                          getter_AddRefs(genericFile));
+      if (NS_FAILED(rv)) {
+        continue;
+      }
+
+      nsCOMPtr<nsIFile> file(do_QueryInterface(genericFile));
+      if (!file) {
+        continue;
+      }
+
+      nsAutoString fileURI;
+      rv = file->GetPath(fileURI);
+      if (NS_FAILED(rv)) {
+        continue;
+      }
+
+      NSString* str = nsCocoaUtils::ToNSString(fileURI);
+      NSURL* url = [NSURL fileURLWithPath:str isDirectory:NO];
+      if (!url || ![url absoluteString]) {
+        continue;
+      }
+      NSString* fileUTType =
+          [UTIHelper stringFromPboardType:(NSString*)kUTTypeFileURL];
+      [pasteboardOutputDict setObject:[url absoluteString] forKey:fileUTType];
+    } else if (flavorStr.EqualsLiteral(kFilePromiseMime)) {
+      NSString* urlPromise = [UTIHelper
+          stringFromPboardType:(NSString*)kPasteboardTypeFileURLPromise];
+      NSString* urlPromiseContent = [UTIHelper
+          stringFromPboardType:(NSString*)kPasteboardTypeFilePromiseContent];
+      [pasteboardOutputDict setObject:[NSArray arrayWithObject:@""]
+                               forKey:urlPromise];
+      [pasteboardOutputDict setObject:[NSArray arrayWithObject:@""]
+                               forKey:urlPromiseContent];
+    } else if (flavorStr.EqualsLiteral(kURLMime)) {
+      nsCOMPtr<nsISupports> genericURL;
+      rv = aTransferable->GetTransferData(flavorStr.get(),
+                                          getter_AddRefs(genericURL));
+      nsCOMPtr<nsISupportsString> urlObject(do_QueryInterface(genericURL));
+
+      nsAutoString url;
+      urlObject->GetData(url);
+
+      NSString* nativeTitle = nil;
+
+      // A newline embedded in the URL means that the form is actually URL +
+      // title. This embedding occurs in nsDragService::GetData.
+      int32_t newlinePos = url.FindChar(char16_t('\n'));
+      if (newlinePos >= 0) {
+        url.Truncate(newlinePos);
+
+        nsAutoString urlTitle;
+        urlObject->GetData(urlTitle);
+        urlTitle.Mid(urlTitle, newlinePos + 1,
+                     urlTitle.Length() - (newlinePos + 1));
+
+        nativeTitle =
+            [NSString stringWithCharacters:reinterpret_cast<const unichar*>(
+                                               urlTitle.get())
+                                    length:urlTitle.Length()];
+      }
+      // The Finder doesn't like getting random binary data aka
+      // Unicode, so change it into an escaped URL containing only
+      // ASCII.
+      nsAutoCString utf8Data = NS_ConvertUTF16toUTF8(url.get(), url.Length());
+      nsAutoCString escData;
+      NS_EscapeURL(utf8Data.get(), utf8Data.Length(),
+                   esc_OnlyNonASCII | esc_AlwaysCopy, escData);
+
+      NSString* nativeURL = [NSString stringWithUTF8String:escData.get()];
+      NSString* publicUrl =
+          [UTIHelper stringFromPboardType:kPublicUrlPboardType];
+      if (!nativeURL) {
+        continue;
+      }
+      [pasteboardOutputDict setObject:nativeURL forKey:publicUrl];
+      if (nativeTitle) {
+        NSArray* urlsAndTitles = @[ @[ nativeURL ], @[ nativeTitle ] ];
+        NSString* urlName =
+            [UTIHelper stringFromPboardType:kPublicUrlNamePboardType];
+        NSString* urlsWithTitles =
+            [UTIHelper stringFromPboardType:kUrlsWithTitlesPboardType];
+        [pasteboardOutputDict setObject:nativeTitle forKey:urlName];
+        [pasteboardOutputDict setObject:urlsAndTitles forKey:urlsWithTitles];
+      }
+    }
+    // If it wasn't a type that we recognize as exportable we don't put it on
+    // the system clipboard. We'll just access it from our cached transferable
+    // when we need it.
+  }
+
+  return pasteboardOutputDict;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+bool nsClipboard::IsStringType(const nsCString& aMIMEType,
+                               NSString** aPboardType) {
+  if (aMIMEType.EqualsLiteral(kTextMime)) {
+    *aPboardType = [UTIHelper stringFromPboardType:NSPasteboardTypeString];
+    return true;
+  } else if (aMIMEType.EqualsLiteral(kRTFMime)) {
+    *aPboardType = [UTIHelper stringFromPboardType:NSPasteboardTypeRTF];
+    return true;
+  } else if (aMIMEType.EqualsLiteral(kHTMLMime)) {
+    *aPboardType = [UTIHelper stringFromPboardType:NSPasteboardTypeHTML];
+    return true;
+  } else {
+    return false;
+  }
+}
+
+// static
+bool nsClipboard::IsImageType(const nsACString& aMIMEType) {
+  return aMIMEType.EqualsLiteral(kPNGImageMime) ||
+         aMIMEType.EqualsLiteral(kJPEGImageMime) ||
+         aMIMEType.EqualsLiteral(kJPGImageMime) ||
+         aMIMEType.EqualsLiteral(kGIFImageMime) ||
+         aMIMEType.EqualsLiteral(kNativeImageMime);
+}
+
+NSString* nsClipboard::WrapHtmlForSystemPasteboard(NSString* aString) {
+  NSString* wrapped =
+      [NSString stringWithFormat:@"<html>"
+                                  "<head>"
+                                  "<meta http-equiv=\"content-type\" "
+                                  "content=\"text/html; charset=utf-8\">"
+                                  "</head>"
+                                  "<body>"
+                                  "%@"
+                                  "</body>"
+                                  "</html>",
+                                 aString];
+  return wrapped;
+}
+
+nsresult nsClipboard::EmptyNativeClipboardData(int32_t aWhichClipboard) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  if (kSelectionCache == aWhichClipboard) {
+    ClearSelectionCache();
+    return NS_OK;
+  }
+
+  if (NSPasteboard* cocoaPasteboard = GetPasteboard(aWhichClipboard)) {
+    [cocoaPasteboard clearContents];
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+mozilla::Result<int32_t, nsresult>
+nsClipboard::GetNativeClipboardSequenceNumber(int32_t aWhichClipboard) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  if (kSelectionCache == aWhichClipboard) {
+    return sSelectionCacheChangeCount;
+  }
+
+  NSPasteboard* cocoaPasteboard = GetPasteboard(aWhichClipboard);
+  if (!cocoaPasteboard) {
+    return mozilla::Err(NS_ERROR_FAILURE);
+  }
+
+  return [cocoaPasteboard changeCount];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(mozilla::Err(NS_ERROR_FAILURE));
+}
diff --git a/widget/cocoa/nsCocoaFeatures.h b/widget/cocoa/nsCocoaFeatures.h
new file mode 100644
index 0000000000..0b157648cc
--- /dev/null
+++ b/widget/cocoa/nsCocoaFeatures.h
@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsCocoaFeatures_h_
+#define nsCocoaFeatures_h_
+
+#include <stdint.h>
+
+/// Note that this class assumes we support the platform we are running on.
+/// For better or worse, if the version is unknown or less than what we
+/// support, we set it to the minimum supported version. GetSystemVersion
+/// is the only call that returns the unadjusted values.
+class nsCocoaFeatures {
+ public:
+  static int32_t macOSVersion();
+  static int32_t macOSVersionMajor();
+  static int32_t macOSVersionMinor();
+  static int32_t macOSVersionBugFix();
+  static bool OnBigSurOrLater();
+  static bool OnMontereyOrLater();
+  static bool OnVenturaOrLater();
+
+  static bool IsAtLeastVersion(int32_t aMajor, int32_t aMinor,
+                               int32_t aBugFix = 0);
+
+  static bool ProcessIsRosettaTranslated();
+
+  // These are utilities that do not change or depend on the value of
+  // mOSVersion and instead just encapsulate the encoding algorithm. Note that
+  // GetVersion actually adjusts to the lowest supported OS, so it will always
+  // return a "supported" version. GetSystemVersion does not make any
+  // modifications.
+  static void GetSystemVersion(int& aMajor, int& aMinor, int& aBugFix);
+  static int32_t GetVersion(int32_t aMajor, int32_t aMinor, int32_t aBugFix);
+  static int32_t ExtractMajorVersion(int32_t aVersion);
+  static int32_t ExtractMinorVersion(int32_t aVersion);
+  static int32_t ExtractBugFixVersion(int32_t aVersion);
+
+ private:
+  nsCocoaFeatures() = delete;  // Prevent instantiation.
+  static void InitializeVersionNumbers();
+
+  static int32_t mOSVersion;
+};
+
+#endif  // nsCocoaFeatures_h_
diff --git a/widget/cocoa/nsCocoaFeatures.mm b/widget/cocoa/nsCocoaFeatures.mm
new file mode 100644
index 0000000000..1dd6344051
--- /dev/null
+++ b/widget/cocoa/nsCocoaFeatures.mm
@@ -0,0 +1,206 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file makes some assumptions about the versions of macOS.
+// We are assuming that the major, minor and bugfix versions are each less than
+// 256.
+// There are MOZ_ASSERTs for that.
+
+// The formula for the version integer is (major << 16) + (minor << 8) + bugfix.
+
+#define MACOS_VERSION_MASK 0x00FFFFFF
+#define MACOS_MAJOR_VERSION_MASK 0x00FFFFFF
+#define MACOS_MINOR_VERSION_MASK 0x00FFFFFF
+#define MACOS_BUGFIX_VERSION_MASK 0x00FFFFFF
+#define MACOS_VERSION_10_0_HEX 0x000A0000
+#define MACOS_VERSION_10_9_HEX 0x000A0900
+#define MACOS_VERSION_10_10_HEX 0x000A0A00
+#define MACOS_VERSION_10_11_HEX 0x000A0B00
+#define MACOS_VERSION_10_12_HEX 0x000A0C00
+#define MACOS_VERSION_10_13_HEX 0x000A0D00
+#define MACOS_VERSION_10_14_HEX 0x000A0E00
+#define MACOS_VERSION_10_15_HEX 0x000A0F00
+#define MACOS_VERSION_10_16_HEX 0x000A1000
+#define MACOS_VERSION_11_0_HEX 0x000B0000
+#define MACOS_VERSION_12_0_HEX 0x000C0000
+#define MACOS_VERSION_13_0_HEX 0x000D0000
+
+#include "nsCocoaFeatures.h"
+#include "nsCocoaUtils.h"
+#include "nsDebug.h"
+#include "nsObjCExceptions.h"
+
+#import <Cocoa/Cocoa.h>
+#include <sys/sysctl.h>
+
+/*static*/ int32_t nsCocoaFeatures::mOSVersion = 0;
+
+// This should not be called with unchecked aMajor, which should be >= 10.
+inline int32_t AssembleVersion(int32_t aMajor, int32_t aMinor,
+                               int32_t aBugFix) {
+  MOZ_ASSERT(aMajor >= 10);
+  return (aMajor << 16) + (aMinor << 8) + aBugFix;
+}
+
+int32_t nsCocoaFeatures::ExtractMajorVersion(int32_t aVersion) {
+  MOZ_ASSERT((aVersion & MACOS_VERSION_MASK) == aVersion);
+  return (aVersion & 0xFF0000) >> 16;
+}
+
+int32_t nsCocoaFeatures::ExtractMinorVersion(int32_t aVersion) {
+  MOZ_ASSERT((aVersion & MACOS_VERSION_MASK) == aVersion);
+  return (aVersion & 0xFF00) >> 8;
+}
+
+int32_t nsCocoaFeatures::ExtractBugFixVersion(int32_t aVersion) {
+  MOZ_ASSERT((aVersion & MACOS_VERSION_MASK) == aVersion);
+  return aVersion & 0xFF;
+}
+
+static int intAtStringIndex(NSArray* array, int index) {
+  return [(NSString*)[array objectAtIndex:index] integerValue];
+}
+
+void nsCocoaFeatures::GetSystemVersion(int& major, int& minor, int& bugfix) {
+  major = minor = bugfix = 0;
+
+  NSString* versionString =
+      [[NSDictionary dictionaryWithContentsOfFile:
+                         @"/System/Library/CoreServices/SystemVersion.plist"]
+          objectForKey:@"ProductVersion"];
+  if (!versionString) {
+    NS_ERROR("Couldn't read /System/Library/CoreServices/SystemVersion.plist "
+             "to determine macOS "
+             "version.");
+    return;
+  }
+  NSArray* versions = [versionString componentsSeparatedByString:@"."];
+  NSUInteger count = [versions count];
+  if (count > 0) {
+    major = intAtStringIndex(versions, 0);
+    if (count > 1) {
+      minor = intAtStringIndex(versions, 1);
+      if (count > 2) {
+        bugfix = intAtStringIndex(versions, 2);
+      }
+    }
+  }
+}
+
+int32_t nsCocoaFeatures::GetVersion(int32_t aMajor, int32_t aMinor,
+                                    int32_t aBugFix) {
+  int32_t macOSVersion;
+  if (aMajor < 10) {
+    aMajor = 10;
+    NS_ERROR("Couldn't determine macOS version, assuming 10.9");
+    macOSVersion = MACOS_VERSION_10_9_HEX;
+  } else if (aMajor == 10 && aMinor < 9) {
+    aMinor = 9;
+    NS_ERROR("macOS version too old, assuming 10.9");
+    macOSVersion = MACOS_VERSION_10_9_HEX;
+  } else {
+    MOZ_ASSERT(aMajor >= 10);
+    MOZ_ASSERT(aMajor < 256);
+    MOZ_ASSERT(aMinor >= 0);
+    MOZ_ASSERT(aMinor < 256);
+    MOZ_ASSERT(aBugFix >= 0);
+    MOZ_ASSERT(aBugFix < 256);
+    macOSVersion = AssembleVersion(aMajor, aMinor, aBugFix);
+  }
+  MOZ_ASSERT(aMajor == ExtractMajorVersion(macOSVersion));
+  MOZ_ASSERT(aMinor == ExtractMinorVersion(macOSVersion));
+  MOZ_ASSERT(aBugFix == ExtractBugFixVersion(macOSVersion));
+  return macOSVersion;
+}
+
+/*static*/ void nsCocoaFeatures::InitializeVersionNumbers() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Provide an autorelease pool to avoid leaking Cocoa objects,
+  // as this gets called before the main autorelease pool is in place.
+  nsAutoreleasePool localPool;
+
+  int major, minor, bugfix;
+  GetSystemVersion(major, minor, bugfix);
+  mOSVersion = GetVersion(major, minor, bugfix);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+/* static */ int32_t nsCocoaFeatures::macOSVersion() {
+  // Don't let this be called while we're first setting the value...
+  MOZ_ASSERT((mOSVersion & MACOS_VERSION_MASK) >= 0);
+  if (!mOSVersion) {
+    mOSVersion = -1;
+    InitializeVersionNumbers();
+  }
+  return mOSVersion;
+}
+
+/* static */ int32_t nsCocoaFeatures::macOSVersionMajor() {
+  return ExtractMajorVersion(macOSVersion());
+}
+
+/* static */ int32_t nsCocoaFeatures::macOSVersionMinor() {
+  return ExtractMinorVersion(macOSVersion());
+}
+
+/* static */ int32_t nsCocoaFeatures::macOSVersionBugFix() {
+  return ExtractBugFixVersion(macOSVersion());
+}
+
+/* static */ bool nsCocoaFeatures::OnBigSurOrLater() {
+  // Account for the version being 10.16 or 11.0 on Big Sur.
+  // The version is reported as 10.16 if SYSTEM_VERSION_COMPAT is set to 1,
+  // or if SYSTEM_VERSION_COMPAT is not set and the application is linked
+  // with a pre-Big Sur SDK.
+  // Firefox sets SYSTEM_VERSION_COMPAT to 0 in its Info.plist, so it'll
+  // usually see the correct 11.* version, despite being linked against an
+  // old SDK. However, it still sees the 10.16 compatibility version when
+  // launched from the command line, see bug 1727624. (This only applies to
+  // the Intel build - the arm64 build is linked against a Big Sur SDK and
+  // always sees the correct version.)
+  return ((macOSVersion() >= MACOS_VERSION_10_16_HEX) ||
+          (macOSVersion() >= MACOS_VERSION_11_0_HEX));
+}
+
+/* static */ bool nsCocoaFeatures::OnMontereyOrLater() {
+  // This check only works if SYSTEM_VERSION_COMPAT is off, otherwise
+  // Monterey pretends to be 10.16 and is indistinguishable from Big Sur.
+  // In practice, this means that an Intel Firefox build can return false
+  // from this function if it's launched from the command line, see bug 1727624.
+  // This will not be an issue anymore once we link against the Big Sur SDK.
+  return (macOSVersion() >= MACOS_VERSION_12_0_HEX);
+}
+
+/* static */ bool nsCocoaFeatures::OnVenturaOrLater() {
+  // See comments above regarding SYSTEM_VERSION_COMPAT.
+  return (macOSVersion() >= MACOS_VERSION_13_0_HEX);
+}
+
+/* static */ bool nsCocoaFeatures::IsAtLeastVersion(int32_t aMajor,
+                                                    int32_t aMinor,
+                                                    int32_t aBugFix) {
+  return macOSVersion() >= GetVersion(aMajor, aMinor, aBugFix);
+}
+
+/*
+ * Returns true if the process is running under Rosetta translation. Returns
+ * false if running natively or if an error was encountered. We use the
+ * `sysctl.proc_translated` sysctl which is documented by Apple to be used
+ * for this purpose. Note: using this in a sandboxed process requires allowing
+ * the sysctl in the sandbox policy.
+ */
+/* static */ bool nsCocoaFeatures::ProcessIsRosettaTranslated() {
+  int ret = 0;
+  size_t size = sizeof(ret);
+  if (sysctlbyname("sysctl.proc_translated", &ret, &size, NULL, 0) == -1) {
+    if (errno != ENOENT) {
+      fprintf(stderr, "Failed to check for translation environment\n");
+    }
+    return false;
+  }
+  return (ret == 1);
+}
diff --git a/widget/cocoa/nsCocoaUtils.h b/widget/cocoa/nsCocoaUtils.h
new file mode 100644
index 0000000000..9e3b76a920
--- /dev/null
+++ b/widget/cocoa/nsCocoaUtils.h
@@ -0,0 +1,595 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsCocoaUtils_h_
+#define nsCocoaUtils_h_
+
+#import <Cocoa/Cocoa.h>
+
+#include "InputData.h"
+#include "nsRect.h"
+#include "imgIContainer.h"
+#include "nsTArray.h"
+#include "Units.h"
+
+// This must be the last include:
+#include "nsObjCExceptions.h"
+
+#include "mozilla/EventForwards.h"
+#include "mozilla/StaticMutex.h"
+#include "mozilla/StaticPtr.h"
+#include "nsIWidget.h"
+
+// Declare the backingScaleFactor method that we want to call
+// on NSView/Window/Screen objects, if they recognize it.
+@interface NSObject (BackingScaleFactorCategory)
+- (CGFloat)backingScaleFactor;
+@end
+
+// Pasteborad types
+extern NSString* const kPublicUrlPboardType;
+extern NSString* const kPublicUrlNamePboardType;
+extern NSString* const kPasteboardConcealedType;
+extern NSString* const kUrlsWithTitlesPboardType;
+extern NSString* const kMozWildcardPboardType;
+extern NSString* const kMozCustomTypesPboardType;
+extern NSString* const kMozFileUrlsPboardType;
+
+@interface UTIHelper : NSObject
++ (NSString*)stringFromPboardType:(NSString*)aType;
+@end
+
+class nsITransferable;
+class nsIWidget;
+
+namespace mozilla {
+class TimeStamp;
+namespace gfx {
+class SourceSurface;
+}  // namespace gfx
+namespace dom {
+class Promise;
+}  // namespace dom
+}  // namespace mozilla
+
+using mozilla::StaticAutoPtr;
+using mozilla::StaticMutex;
+
+// Used to retain a Cocoa object for the remainder of a method's execution.
+class nsAutoRetainCocoaObject {
+ public:
+  explicit nsAutoRetainCocoaObject(id anObject) {
+    NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+    mObject = [anObject retain];
+    NS_OBJC_END_TRY_IGNORE_BLOCK;
+  }
+  ~nsAutoRetainCocoaObject() {
+    NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+    [mObject release];
+    NS_OBJC_END_TRY_IGNORE_BLOCK;
+  }
+
+ private:
+  id mObject;  // [STRONG]
+};
+
+// Provide a local autorelease pool for the remainder of a method's execution.
+class nsAutoreleasePool {
+ public:
+  nsAutoreleasePool() { mLocalPool = [[NSAutoreleasePool alloc] init]; }
+  ~nsAutoreleasePool() { [mLocalPool release]; }
+
+ private:
+  NSAutoreleasePool* mLocalPool;
+};
+
+@interface NSApplication (Undocumented)
+
+// Present in all versions of OS X from (at least) 10.2.8 through 10.5.
+- (BOOL)_isRunningModal;
+- (BOOL)_isRunningAppModal;
+
+// Send an event to the current Cocoa app-modal session.  Present in all
+// versions of OS X from (at least) 10.2.8 through 10.5.
+- (void)_modalSession:(NSModalSession)aSession sendEvent:(NSEvent*)theEvent;
+
+@end
+
+struct KeyBindingsCommand {
+  SEL selector;
+  id data;
+};
+
+@interface NativeKeyBindingsRecorder : NSResponder {
+ @private
+  nsTArray<KeyBindingsCommand>* mCommands;
+}
+
+- (void)startRecording:(nsTArray<KeyBindingsCommand>&)aCommands;
+
+- (void)doCommandBySelector:(SEL)aSelector;
+
+- (void)insertText:(id)aString;
+
+@end  // NativeKeyBindingsRecorder
+
+class nsCocoaUtils {
+  typedef mozilla::gfx::SourceSurface SourceSurface;
+  typedef mozilla::LayoutDeviceIntPoint LayoutDeviceIntPoint;
+  typedef mozilla::LayoutDeviceIntRect LayoutDeviceIntRect;
+  typedef mozilla::dom::Promise Promise;
+  typedef StaticAutoPtr<nsTArray<RefPtr<Promise>>> PromiseArray;
+
+ public:
+  // Get the backing scale factor from an object that supports this selector
+  // (NSView/Window/Screen, on 10.7 or later), returning 1.0 if not supported
+  static CGFloat GetBackingScaleFactor(id aObject) {
+    if (HiDPIEnabled() &&
+        [aObject respondsToSelector:@selector(backingScaleFactor)]) {
+      return [aObject backingScaleFactor];
+    }
+    return 1.0;
+  }
+
+  // Conversions between Cocoa points and device pixels, given the backing
+  // scale factor from a view/window/screen.
+  static int32_t CocoaPointsToDevPixels(CGFloat aPts, CGFloat aBackingScale) {
+    return NSToIntRound(aPts * aBackingScale);
+  }
+
+  static LayoutDeviceIntPoint CocoaPointsToDevPixels(const NSPoint& aPt,
+                                                     CGFloat aBackingScale) {
+    return LayoutDeviceIntPoint(NSToIntRound(aPt.x * aBackingScale),
+                                NSToIntRound(aPt.y * aBackingScale));
+  }
+
+  static LayoutDeviceIntPoint CocoaPointsToDevPixelsRoundDown(
+      const NSPoint& aPt, CGFloat aBackingScale) {
+    return LayoutDeviceIntPoint(NSToIntFloor(aPt.x * aBackingScale),
+                                NSToIntFloor(aPt.y * aBackingScale));
+  }
+
+  static LayoutDeviceIntRect CocoaPointsToDevPixels(const NSRect& aRect,
+                                                    CGFloat aBackingScale) {
+    return LayoutDeviceIntRect(NSToIntRound(aRect.origin.x * aBackingScale),
+                               NSToIntRound(aRect.origin.y * aBackingScale),
+                               NSToIntRound(aRect.size.width * aBackingScale),
+                               NSToIntRound(aRect.size.height * aBackingScale));
+  }
+
+  static CGFloat DevPixelsToCocoaPoints(int32_t aPixels,
+                                        CGFloat aBackingScale) {
+    return (CGFloat)aPixels / aBackingScale;
+  }
+
+  static NSPoint DevPixelsToCocoaPoints(
+      const mozilla::LayoutDeviceIntPoint& aPt, CGFloat aBackingScale) {
+    return NSMakePoint((CGFloat)aPt.x / aBackingScale,
+                       (CGFloat)aPt.y / aBackingScale);
+  }
+
+  // Implements an NSPoint equivalent of -[NSWindow convertRectFromScreen:].
+  static NSPoint ConvertPointFromScreen(NSWindow* aWindow, const NSPoint& aPt) {
+    return
+        [aWindow convertRectFromScreen:NSMakeRect(aPt.x, aPt.y, 0, 0)].origin;
+  }
+
+  // Implements an NSPoint equivalent of -[NSWindow convertRectToScreen:].
+  static NSPoint ConvertPointToScreen(NSWindow* aWindow, const NSPoint& aPt) {
+    return [aWindow convertRectToScreen:NSMakeRect(aPt.x, aPt.y, 0, 0)].origin;
+  }
+
+  static NSRect DevPixelsToCocoaPoints(const LayoutDeviceIntRect& aRect,
+                                       CGFloat aBackingScale) {
+    return NSMakeRect((CGFloat)aRect.X() / aBackingScale,
+                      (CGFloat)aRect.Y() / aBackingScale,
+                      (CGFloat)aRect.Width() / aBackingScale,
+                      (CGFloat)aRect.Height() / aBackingScale);
+  }
+
+  // Returns the given y coordinate, which must be in screen coordinates,
+  // flipped from Gecko to Cocoa or Cocoa to Gecko.
+  static float FlippedScreenY(float y);
+
+  // The following functions come in "DevPix" variants that work with
+  // backing-store (device pixel) coordinates, as well as the original
+  // versions that expect coordinates in Cocoa points/CSS pixels.
+  // The difference becomes important in HiDPI display modes, where Cocoa
+  // points and backing-store pixels are no longer 1:1.
+
+  // Gecko rects (nsRect) contain an origin (x,y) in a coordinate
+  // system with (0,0) in the top-left of the primary screen. Cocoa rects
+  // (NSRect) contain an origin (x,y) in a coordinate system with (0,0)
+  // in the bottom-left of the primary screen. Both nsRect and NSRect
+  // contain width/height info, with no difference in their use.
+  // This function does no scaling, so the Gecko coordinates are
+  // expected to be desktop pixels, which are equal to Cocoa points
+  // (by definition).
+  static NSRect GeckoRectToCocoaRect(const mozilla::DesktopIntRect& geckoRect);
+  static NSPoint GeckoPointToCocoaPoint(const mozilla::DesktopPoint& aPoint);
+
+  // Converts aGeckoRect in dev pixels to points in Cocoa coordinates
+  static NSRect GeckoRectToCocoaRectDevPix(
+      const mozilla::LayoutDeviceIntRect& aGeckoRect, CGFloat aBackingScale);
+
+  // See explanation for geckoRectToCocoaRect, guess what this does...
+  static mozilla::DesktopIntRect CocoaRectToGeckoRect(const NSRect& cocoaRect);
+
+  static mozilla::LayoutDeviceIntRect CocoaRectToGeckoRectDevPix(
+      const NSRect& aCocoaRect, CGFloat aBackingScale);
+
+  // Gives the location for the event in screen coordinates. Do not call this
+  // unless the window the event was originally targeted at is still alive!
+  // anEvent may be nil -- in that case the current mouse location is returned.
+  static NSPoint ScreenLocationForEvent(NSEvent* anEvent);
+
+  // Determines if an event happened over a window, whether or not the event
+  // is for the window. Does not take window z-order into account.
+  static BOOL IsEventOverWindow(NSEvent* anEvent, NSWindow* aWindow);
+
+  // Events are set up so that their coordinates refer to the window to which
+  // they were originally sent. If we reroute the event somewhere else, we'll
+  // have to get the window coordinates this way. Do not call this unless the
+  // window the event was originally targeted at is still alive!
+  static NSPoint EventLocationForWindow(NSEvent* anEvent, NSWindow* aWindow);
+
+  static BOOL IsMomentumScrollEvent(NSEvent* aEvent);
+  static BOOL EventHasPhaseInformation(NSEvent* aEvent);
+
+  // Hides the Menu bar and the Dock. Multiple hide/show requests can be nested.
+  static void HideOSChromeOnScreen(bool aShouldHide);
+
+  static nsIWidget* GetHiddenWindowWidget();
+
+  /**
+   * Should the application restore its state because it was launched by the OS
+   * at login?
+   */
+  static BOOL ShouldRestoreStateDueToLaunchAtLogin();
+
+  static void PrepareForNativeAppModalDialog();
+  static void CleanUpAfterNativeAppModalDialog();
+
+  // 3 utility functions to go from a frame of imgIContainer to CGImage and then
+  // to NSImage Convert imgIContainer -> CGImageRef, caller owns result
+
+  /** Creates a <code>CGImageRef</code> from a frame contained in an
+     <code>imgIContainer</code>. Copies the pixel data from the indicated frame
+     of the <code>imgIContainer</code> into a new <code>CGImageRef</code>. The
+     caller owns the <code>CGImageRef</code>.
+      @param aFrame the frame to convert
+      @param aResult the resulting CGImageRef
+      @param aIsEntirelyBlack an outparam that, if non-null, will be set to a
+                              bool that indicates whether the RGB values on all
+                              pixels are zero
+      @return NS_OK if the conversion worked, NS_ERROR_FAILURE otherwise
+   */
+  static nsresult CreateCGImageFromSurface(SourceSurface* aSurface,
+                                           CGImageRef* aResult,
+                                           bool* aIsEntirelyBlack = nullptr);
+
+  /** Creates a Cocoa <code>NSImage</code> from a <code>CGImageRef</code>.
+      Copies the pixel data from the <code>CGImageRef</code> into a new
+     <code>NSImage</code>. The caller owns the <code>NSImage</code>.
+      @param aInputImage the image to convert
+      @param aResult the resulting NSImage
+      @return NS_OK if the conversion worked, NS_ERROR_FAILURE otherwise
+   */
+  static nsresult CreateNSImageFromCGImage(CGImageRef aInputImage,
+                                           NSImage** aResult);
+
+  /** Creates a Cocoa <code>NSImage</code> from a frame of an
+     <code>imgIContainer</code>. Combines the two methods above. The caller owns
+     the <code>NSImage</code>.
+      @param aImage the image to extract a frame from
+      @param aWhichFrame the frame to extract (see imgIContainer FRAME_*)
+      @param aComputedStyle the ComputedStyle of the element that the image is
+     for, to support SVG context paint properties, can be null
+      @param aResult the resulting NSImage
+      @param scaleFactor the desired scale factor of the NSImage (2 for a retina
+     display)
+      @param aIsEntirelyBlack an outparam that, if non-null, will be set to a
+                              bool that indicates whether the RGB values on all
+                              pixels are zero
+      @return NS_OK if the conversion worked, NS_ERROR_FAILURE otherwise
+   */
+  static nsresult CreateNSImageFromImageContainer(
+      imgIContainer* aImage, uint32_t aWhichFrame,
+      const nsPresContext* aPresContext,
+      const mozilla::ComputedStyle* aComputedStyle, NSImage** aResult,
+      CGFloat scaleFactor, bool* aIsEntirelyBlack = nullptr);
+
+  /** Creates a Cocoa <code>NSImage</code> from a frame of an
+     <code>imgIContainer</code>. The new <code>NSImage</code> will have both a
+     regular and HiDPI representation. The caller owns the <code>NSImage</code>.
+      @param aImage the image to extract a frame from
+      @param aWhichFrame the frame to extract (see imgIContainer FRAME_*)
+      @param aComputedStyle the ComputedStyle of the element that the image is
+     for, to support SVG context paint properties, can be null
+      @param aResult the resulting NSImage
+      @param aIsEntirelyBlack an outparam that, if non-null, will be set to a
+                              bool that indicates whether the RGB values on all
+                              pixels are zero
+      @return NS_OK if the conversion worked, NS_ERROR_FAILURE otherwise
+   */
+  static nsresult CreateDualRepresentationNSImageFromImageContainer(
+      imgIContainer* aImage, uint32_t aWhichFrame,
+      const nsPresContext* aPresContext,
+      const mozilla::ComputedStyle* aComputedStyle, NSImage** aResult,
+      bool* aIsEntirelyBlack = nullptr);
+
+  /**
+   * Returns nsAString for aSrc.
+   */
+  static void GetStringForNSString(const NSString* aSrc, nsAString& aDist);
+
+  /**
+   * Makes NSString instance for aString.
+   */
+  static NSString* ToNSString(const nsAString& aString);
+
+  /**
+   * Returns an NSURL instance for the provided string.
+   */
+  static NSURL* ToNSURL(const nsAString& aURLString);
+
+  /**
+   * Makes NSString instance for aCString.
+   */
+  static NSString* ToNSString(const nsACString& aCString);
+
+  /**
+   * Returns NSRect for aGeckoRect.
+   * Just copies values between the two types; it does no coordinate-system
+   * conversion, so both rects must have the same coordinate origin/direction.
+   */
+  static void GeckoRectToNSRect(const nsIntRect& aGeckoRect,
+                                NSRect& aOutCocoaRect);
+
+  /**
+   * Returns Gecko rect for aCocoaRect.
+   * Just copies values between the two types; it does no coordinate-system
+   * conversion, so both rects must have the same coordinate origin/direction.
+   */
+  static void NSRectToGeckoRect(const NSRect& aCocoaRect,
+                                nsIntRect& aOutGeckoRect);
+
+  /**
+   * Makes NSEvent instance for aEventTytpe and aEvent.
+   */
+  static NSEvent* MakeNewCocoaEventWithType(NSEventType aEventType,
+                                            NSEvent* aEvent);
+
+  /**
+   * Makes a cocoa event from a widget keyboard event.
+   */
+  static NSEvent* MakeNewCococaEventFromWidgetEvent(
+      const mozilla::WidgetKeyboardEvent& aKeyEvent, NSInteger aWindowNumber,
+      NSGraphicsContext* aContext);
+
+  /**
+   * Initializes WidgetInputEvent for aNativeEvent or aModifiers.
+   */
+  static void InitInputEvent(mozilla::WidgetInputEvent& aInputEvent,
+                             NSEvent* aNativeEvent);
+
+  /**
+   * Converts the native modifiers from aNativeEvent into WidgetMouseEvent
+   * Modifiers. aNativeEvent can be null.
+   */
+  static mozilla::Modifiers ModifiersForEvent(NSEvent* aNativeEvent);
+
+  /**
+   * ConvertToCarbonModifier() returns carbon modifier flags for the cocoa
+   * modifier flags.
+   * NOTE: The result never includes right*Key.
+   */
+  static UInt32 ConvertToCarbonModifier(NSUInteger aCocoaModifier);
+
+  /**
+   * Whether to support HiDPI rendering. For testing purposes, to be removed
+   * once we're comfortable with the HiDPI behavior.
+   */
+  static bool HiDPIEnabled();
+
+  /**
+   * Keys can optionally be bound by system or user key bindings to one or more
+   * commands based on selectors. This collects any such commands in the
+   * provided array.
+   */
+  static void GetCommandsFromKeyEvent(NSEvent* aEvent,
+                                      nsTArray<KeyBindingsCommand>& aCommands);
+
+  /**
+   * Converts the string name of a Gecko key (like "VK_HOME") to the
+   * corresponding Cocoa Unicode character.
+   */
+  static uint32_t ConvertGeckoNameToMacCharCode(const nsAString& aKeyCodeName);
+
+  /**
+   * Converts a Gecko key code (like NS_VK_HOME) to the corresponding Cocoa
+   * Unicode character.
+   */
+  static uint32_t ConvertGeckoKeyCodeToMacCharCode(uint32_t aKeyCode);
+
+  /**
+   * Converts Gecko native modifier flags for `nsIWidget::SynthesizeNative*()`
+   * to native modifier flags of macOS.
+   */
+  static NSEventModifierFlags ConvertWidgetModifiersToMacModifierFlags(
+      nsIWidget::Modifiers aNativeModifiers);
+
+  /**
+   * Get the mouse button, which depends on the event's type and buttonNumber.
+   * Returns MouseButton::ePrimary for non-mouse events.
+   */
+  static mozilla::MouseButton ButtonForEvent(NSEvent* aEvent);
+
+  /**
+   * Convert string with font attribute to NSMutableAttributedString
+   */
+  static NSMutableAttributedString* GetNSMutableAttributedString(
+      const nsAString& aText, const nsTArray<mozilla::FontRange>& aFontRanges,
+      const bool aIsVertical, const CGFloat aBackingScaleFactor);
+
+  /**
+   * Compute TimeStamp from an event's timestamp.
+   * If aEventTime is 0, this returns current timestamp.
+   */
+  static mozilla::TimeStamp GetEventTimeStamp(NSTimeInterval aEventTime);
+
+  /**
+   * Check whether double clicking on the titlebar should cause the window to
+   * zoom (maximize).
+   */
+  static bool ShouldZoomOnTitlebarDoubleClick();
+
+  /**
+   * Check whether double clicking on the titlebar should cause the window to
+   * minimize.
+   */
+  static bool ShouldMinimizeOnTitlebarDoubleClick();
+
+  /**
+   * Get the current video capture permission status.
+   * Returns NS_ERROR_NOT_IMPLEMENTED on 10.13 and earlier macOS versions.
+   */
+  static nsresult GetVideoCapturePermissionState(uint16_t& aPermissionState);
+
+  /**
+   * Get the current audio capture permission status.
+   * Returns NS_ERROR_NOT_IMPLEMENTED on 10.13 and earlier macOS versions.
+   */
+  static nsresult GetAudioCapturePermissionState(uint16_t& aPermissionState);
+
+  /**
+   * Get the current screen capture permission status.
+   * Returns NS_ERROR_NOT_IMPLEMENTED on 10.14 and earlier macOS versions.
+   */
+  static nsresult GetScreenCapturePermissionState(uint16_t& aPermissionState);
+
+  /**
+   * Request video capture permission from the OS. Caller must be running
+   * on the main thread and the promise will be resolved on the main thread.
+   * Returns NS_ERROR_NOT_IMPLEMENTED on 10.13 and earlier macOS versions.
+   */
+  static nsresult RequestVideoCapturePermission(RefPtr<Promise>& aPromise);
+
+  /**
+   * Request audio capture permission from the OS. Caller must be running
+   * on the main thread and the promise will be resolved on the main thread.
+   * Returns NS_ERROR_NOT_IMPLEMENTED on 10.13 and earlier macOS versions.
+   */
+  static nsresult RequestAudioCapturePermission(RefPtr<Promise>& aPromise);
+
+  /**
+   * Request screen capture permission from the OS using an unreliable method.
+   */
+  static nsresult MaybeRequestScreenCapturePermission();
+
+  static void InvalidateHiDPIState();
+
+  static mozilla::PanGestureInput CreatePanGestureEvent(
+      NSEvent* aNativeEvent, mozilla::TimeStamp aTimeStamp,
+      const mozilla::ScreenPoint& aPanStartPoint,
+      const mozilla::ScreenPoint& aPreciseDelta,
+      const mozilla::gfx::IntPoint& aLineOrPageDelta,
+      mozilla::Modifiers aModifiers);
+
+  /**
+   * Return true if aAvailableType is a vaild NSPasteboard type.
+   */
+  static bool IsValidPasteboardType(NSString* aAvailableType,
+                                    bool aAllowFileURL);
+
+  /**
+   * Set data for specific type from NSPasteboardItem to Transferable.
+   */
+  static void SetTransferDataForTypeFromPasteboardItem(
+      nsITransferable* aTransferable, const nsCString& aFlavor,
+      NSPasteboardItem* aItem);
+
+ private:
+  /**
+   * Completion handlers used as an argument to the macOS API to
+   * request media capture permission. These are called asynchronously
+   * on an arbitrary dispatch queue.
+   */
+  static void (^AudioCompletionHandler)(BOOL);
+  static void (^VideoCompletionHandler)(BOOL);
+
+  /**
+   * Called from the audio and video completion handlers in order to
+   * dispatch the handling back to the main thread.
+   */
+  static void ResolveAudioCapturePromises(bool aGranted);
+  static void ResolveVideoCapturePromises(bool aGranted);
+
+  /**
+   * Main implementation for Request{Audio,Video}CapturePermission.
+   * @param aType the AVMediaType to request capture permission for
+   * @param aPromise the Promise to resolve when capture permission
+   *                 is either allowed or denied
+   * @param aPromiseList the array of promises to save |aPromise| in
+   * @param aHandler the block function (either ResolveAudioCapturePromises
+   *                 or ResolveVideoCapturePromises) to be used as
+   *                 the requestAccessForMediaType callback.
+   */
+  static nsresult RequestCapturePermission(NSString* aType,
+                                           RefPtr<Promise>& aPromise,
+                                           PromiseArray& aPromiseList,
+                                           void (^aHandler)(BOOL granted));
+  /**
+   * Resolves the pending promises that are waiting for a response
+   * to a request video or audio capture permission.
+   */
+  static void ResolveMediaCapturePromises(bool aGranted,
+                                          PromiseArray& aPromiseList);
+
+  /**
+   * Get string data for a specific type from NSPasteboardItem.
+   */
+  static NSString* GetStringForTypeFromPasteboardItem(
+      NSPasteboardItem* aItem, const NSString* aType,
+      bool aAllowFileURL = false);
+
+  /**
+   * Get the file path from NSPasteboardItem.
+   */
+  static NSString* GetFilePathFromPasteboardItem(NSPasteboardItem* aItem);
+
+  /**
+   * Get the title for URL from NSPasteboardItem.
+   */
+  static NSString* GetTitleForURLFromPasteboardItem(NSPasteboardItem* item);
+
+  /**
+   * Did the OS launch the application at login?
+   */
+  static BOOL WasLaunchedAtLogin();
+
+  /**
+   * Should the application restore its state because it was launched by the OS
+   * at login?
+   */
+  static BOOL ShouldRestoreStateDueToLaunchAtLoginImpl();
+
+  /**
+   * Array of promises waiting to be resolved due to a video capture request.
+   */
+  static PromiseArray sVideoCapturePromises;
+
+  /**
+   * Array of promises waiting to be resolved due to an audio capture request.
+   */
+  static PromiseArray sAudioCapturePromises;
+
+  /**
+   * Lock protecting |sVideoCapturePromises| and |sAudioCapturePromises|.
+   */
+  static StaticMutex sMediaCaptureMutex MOZ_UNANNOTATED;
+};
+
+#endif  // nsCocoaUtils_h_
diff --git a/widget/cocoa/nsCocoaUtils.mm b/widget/cocoa/nsCocoaUtils.mm
new file mode 100644
index 0000000000..f3a7604762
--- /dev/null
+++ b/widget/cocoa/nsCocoaUtils.mm
@@ -0,0 +1,1857 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <AVFoundation/AVFoundation.h>
+
+#include <cmath>
+
+#include "AppleUtils.h"
+#include "gfx2DGlue.h"
+#include "gfxContext.h"
+#include "gfxPlatform.h"
+#include "gfxUtils.h"
+#include "ImageRegion.h"
+#include "nsClipboard.h"
+#include "nsCocoaUtils.h"
+#include "nsChildView.h"
+#include "nsMenuBarX.h"
+#include "nsCocoaWindow.h"
+#include "nsCOMPtr.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsIAppShellService.h"
+#include "nsIOSPermissionRequest.h"
+#include "nsIRunnable.h"
+#include "nsIAppWindow.h"
+#include "nsIBaseWindow.h"
+#include "nsITransferable.h"
+#include "nsMenuUtilsX.h"
+#include "nsNetUtil.h"
+#include "nsPrimitiveHelpers.h"
+#include "nsToolkit.h"
+#include "nsCRT.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Logging.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/StaticMutex.h"
+#include "mozilla/StaticPrefs_media.h"
+#include "mozilla/SVGImageContext.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/gfx/2D.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+using mozilla::dom::Promise;
+using mozilla::gfx::DataSourceSurface;
+using mozilla::gfx::DrawTarget;
+using mozilla::gfx::IntPoint;
+using mozilla::gfx::IntRect;
+using mozilla::gfx::IntSize;
+using mozilla::gfx::SamplingFilter;
+using mozilla::gfx::SourceSurface;
+using mozilla::gfx::SurfaceFormat;
+using mozilla::image::ImageRegion;
+
+LazyLogModule gCocoaUtilsLog("nsCocoaUtils");
+#undef LOG
+#define LOG(...) MOZ_LOG(gCocoaUtilsLog, LogLevel::Debug, (__VA_ARGS__))
+
+/*
+ * For each audio and video capture request, we hold an owning reference
+ * to a promise to be resolved when the request's async callback is invoked.
+ * sVideoCapturePromises and sAudioCapturePromises are arrays of video and
+ * audio promises waiting for to be resolved. Each array is protected by a
+ * mutex.
+ */
+nsCocoaUtils::PromiseArray nsCocoaUtils::sVideoCapturePromises;
+nsCocoaUtils::PromiseArray nsCocoaUtils::sAudioCapturePromises;
+StaticMutex nsCocoaUtils::sMediaCaptureMutex;
+
+/**
+ * Pasteboard types
+ */
+NSString* const kPublicUrlPboardType = @"public.url";
+NSString* const kPublicUrlNamePboardType = @"public.url-name";
+NSString* const kPasteboardConcealedType = @"org.nspasteboard.ConcealedType";
+NSString* const kUrlsWithTitlesPboardType = @"WebURLsWithTitlesPboardType";
+NSString* const kMozWildcardPboardType = @"org.mozilla.MozillaWildcard";
+NSString* const kMozCustomTypesPboardType = @"org.mozilla.custom-clipdata";
+NSString* const kMozFileUrlsPboardType = @"org.mozilla.file-urls";
+
+@implementation UTIHelper
+
++ (NSString*)stringFromPboardType:(NSString*)aType {
+  if ([aType isEqualToString:kMozWildcardPboardType] ||
+      [aType isEqualToString:kMozCustomTypesPboardType] ||
+      [aType isEqualToString:kPasteboardConcealedType] ||
+      [aType isEqualToString:kPublicUrlPboardType] ||
+      [aType isEqualToString:kPublicUrlNamePboardType] ||
+      [aType isEqualToString:kMozFileUrlsPboardType] ||
+      [aType isEqualToString:(NSString*)kPasteboardTypeFileURLPromise] ||
+      [aType isEqualToString:(NSString*)kPasteboardTypeFilePromiseContent] ||
+      [aType isEqualToString:(NSString*)kUTTypeFileURL] ||
+      [aType isEqualToString:NSStringPboardType] ||
+      [aType isEqualToString:NSPasteboardTypeString] ||
+      [aType isEqualToString:NSPasteboardTypeHTML] ||
+      [aType isEqualToString:NSPasteboardTypeRTF] ||
+      [aType isEqualToString:NSPasteboardTypeTIFF] ||
+      [aType isEqualToString:NSPasteboardTypePNG]) {
+    return [NSString stringWithString:aType];
+  }
+  NSString* dynamicType = (NSString*)UTTypeCreatePreferredIdentifierForTag(
+      kUTTagClassNSPboardType, (CFStringRef)aType, kUTTypeData);
+  NSString* result = [NSString stringWithString:dynamicType];
+  [dynamicType release];
+  return result;
+}
+
+@end  // UTIHelper
+
+static float MenuBarScreenHeight() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSArray* allScreens = [NSScreen screens];
+  if ([allScreens count]) {
+    return [[allScreens objectAtIndex:0] frame].size.height;
+  }
+
+  return 0.0;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(0.0);
+}
+
+float nsCocoaUtils::FlippedScreenY(float y) {
+  return MenuBarScreenHeight() - y;
+}
+
+NSRect nsCocoaUtils::GeckoRectToCocoaRect(const DesktopIntRect& geckoRect) {
+  // We only need to change the Y coordinate by starting with the primary screen
+  // height and subtracting the gecko Y coordinate of the bottom of the rect.
+  return NSMakeRect(geckoRect.x, MenuBarScreenHeight() - geckoRect.YMost(),
+                    geckoRect.width, geckoRect.height);
+}
+
+NSPoint nsCocoaUtils::GeckoPointToCocoaPoint(
+    const mozilla::DesktopPoint& aPoint) {
+  return NSMakePoint(aPoint.x, MenuBarScreenHeight() - aPoint.y);
+}
+
+NSRect nsCocoaUtils::GeckoRectToCocoaRectDevPix(
+    const LayoutDeviceIntRect& aGeckoRect, CGFloat aBackingScale) {
+  return NSMakeRect(aGeckoRect.x / aBackingScale,
+                    MenuBarScreenHeight() - aGeckoRect.YMost() / aBackingScale,
+                    aGeckoRect.width / aBackingScale,
+                    aGeckoRect.height / aBackingScale);
+}
+
+DesktopIntRect nsCocoaUtils::CocoaRectToGeckoRect(const NSRect& cocoaRect) {
+  // We only need to change the Y coordinate by starting with the primary screen
+  // height and subtracting both the cocoa y origin and the height of the
+  // cocoa rect.
+  DesktopIntRect rect;
+  rect.x = NSToIntRound(cocoaRect.origin.x);
+  rect.y =
+      NSToIntRound(FlippedScreenY(cocoaRect.origin.y + cocoaRect.size.height));
+  rect.width = NSToIntRound(cocoaRect.origin.x + cocoaRect.size.width) - rect.x;
+  rect.height = NSToIntRound(FlippedScreenY(cocoaRect.origin.y)) - rect.y;
+  return rect;
+}
+
+LayoutDeviceIntRect nsCocoaUtils::CocoaRectToGeckoRectDevPix(
+    const NSRect& aCocoaRect, CGFloat aBackingScale) {
+  LayoutDeviceIntRect rect;
+  rect.x = NSToIntRound(aCocoaRect.origin.x * aBackingScale);
+  rect.y = NSToIntRound(
+      FlippedScreenY(aCocoaRect.origin.y + aCocoaRect.size.height) *
+      aBackingScale);
+  rect.width = NSToIntRound((aCocoaRect.origin.x + aCocoaRect.size.width) *
+                            aBackingScale) -
+               rect.x;
+  rect.height =
+      NSToIntRound(FlippedScreenY(aCocoaRect.origin.y) * aBackingScale) -
+      rect.y;
+  return rect;
+}
+
+NSPoint nsCocoaUtils::ScreenLocationForEvent(NSEvent* anEvent) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // Don't trust mouse locations of mouse move events, see bug 443178.
+  if (!anEvent || [anEvent type] == NSEventTypeMouseMoved)
+    return [NSEvent mouseLocation];
+
+  // Pin momentum scroll events to the location of the last user-controlled
+  // scroll event.
+  if (IsMomentumScrollEvent(anEvent))
+    return ChildViewMouseTracker::sLastScrollEventScreenLocation;
+
+  return nsCocoaUtils::ConvertPointToScreen([anEvent window],
+                                            [anEvent locationInWindow]);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NSMakePoint(0.0, 0.0));
+}
+
+BOOL nsCocoaUtils::IsEventOverWindow(NSEvent* anEvent, NSWindow* aWindow) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return NSPointInRect(ScreenLocationForEvent(anEvent), [aWindow frame]);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NO);
+}
+
+NSPoint nsCocoaUtils::EventLocationForWindow(NSEvent* anEvent,
+                                             NSWindow* aWindow) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return nsCocoaUtils::ConvertPointFromScreen(aWindow,
+                                              ScreenLocationForEvent(anEvent));
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NSMakePoint(0.0, 0.0));
+}
+
+BOOL nsCocoaUtils::IsMomentumScrollEvent(NSEvent* aEvent) {
+  return [aEvent type] == NSEventTypeScrollWheel &&
+         [aEvent momentumPhase] != NSEventPhaseNone;
+}
+
+BOOL nsCocoaUtils::EventHasPhaseInformation(NSEvent* aEvent) {
+  return [aEvent phase] != NSEventPhaseNone ||
+         [aEvent momentumPhase] != NSEventPhaseNone;
+}
+
+void nsCocoaUtils::HideOSChromeOnScreen(bool aShouldHide) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Keep track of how many hiding requests have been made, so that they can
+  // be nested.
+  static int sHiddenCount = 0;
+
+  sHiddenCount += aShouldHide ? 1 : -1;
+  NS_ASSERTION(sHiddenCount >= 0, "Unbalanced HideMenuAndDockForWindow calls");
+
+  NSApplicationPresentationOptions options =
+      sHiddenCount <= 0 ? NSApplicationPresentationDefault
+                        : NSApplicationPresentationHideDock |
+                              NSApplicationPresentationHideMenuBar;
+  [NSApp setPresentationOptions:options];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+#define NS_APPSHELLSERVICE_CONTRACTID "@mozilla.org/appshell/appShellService;1"
+nsIWidget* nsCocoaUtils::GetHiddenWindowWidget() {
+  nsCOMPtr<nsIAppShellService> appShell(
+      do_GetService(NS_APPSHELLSERVICE_CONTRACTID));
+  if (!appShell) {
+    NS_WARNING(
+        "Couldn't get AppShellService in order to get hidden window ref");
+    return nullptr;
+  }
+
+  nsCOMPtr<nsIAppWindow> hiddenWindow;
+  appShell->GetHiddenWindow(getter_AddRefs(hiddenWindow));
+  if (!hiddenWindow) {
+    // Don't warn, this happens during shutdown, bug 358607.
+    return nullptr;
+  }
+
+  nsCOMPtr<nsIBaseWindow> baseHiddenWindow;
+  baseHiddenWindow = do_GetInterface(hiddenWindow);
+  if (!baseHiddenWindow) {
+    NS_WARNING("Couldn't get nsIBaseWindow from hidden window (nsIAppWindow)");
+    return nullptr;
+  }
+
+  nsCOMPtr<nsIWidget> hiddenWindowWidget;
+  if (NS_FAILED(baseHiddenWindow->GetMainWidget(
+          getter_AddRefs(hiddenWindowWidget)))) {
+    NS_WARNING("Couldn't get nsIWidget from hidden window (nsIBaseWindow)");
+    return nullptr;
+  }
+
+  return hiddenWindowWidget;
+}
+
+BOOL nsCocoaUtils::WasLaunchedAtLogin() {
+  ProcessSerialNumber processSerialNumber = {0, kCurrentProcess};
+  ProcessInfoRec processInfoRec = {};
+  processInfoRec.processInfoLength = sizeof(processInfoRec);
+
+  // There is currently no replacement for ::GetProcessInformation, which has
+  // been deprecated since macOS 10.9.
+  if (::GetProcessInformation(&processSerialNumber, &processInfoRec) == noErr) {
+    ProcessInfoRec parentProcessInfo = {};
+    parentProcessInfo.processInfoLength = sizeof(parentProcessInfo);
+    if (::GetProcessInformation(&processInfoRec.processLauncher,
+                                &parentProcessInfo) == noErr) {
+      return parentProcessInfo.processSignature == 'lgnw';
+    }
+  }
+  return NO;
+}
+
+BOOL nsCocoaUtils::ShouldRestoreStateDueToLaunchAtLoginImpl() {
+  // Check if we were launched by macOS as a result of having
+  // "Reopen windows..." selected during a restart.
+  if (!WasLaunchedAtLogin()) {
+    return NO;
+  }
+
+  CFStringRef lgnwPlistName = CFSTR("com.apple.loginwindow");
+  CFStringRef saveStateKey = CFSTR("TALLogoutSavesState");
+  CFPropertyListRef lgnwPlist = (CFPropertyListRef)(::CFPreferencesCopyAppValue(
+      saveStateKey, lgnwPlistName));
+  // The .plist doesn't exist unless the user changed the "Reopen windows..."
+  // preference. If it doesn't exist, restore by default (as this is the macOS
+  // default).
+  // https://developer.apple.com/library/mac/documentation/macosx/conceptual/bpsystemstartup/chapters/CustomLogin.html
+  if (!lgnwPlist) {
+    return YES;
+  }
+
+  if (CFBooleanRef shouldRestoreState = static_cast<CFBooleanRef>(lgnwPlist)) {
+    return ::CFBooleanGetValue(shouldRestoreState);
+  }
+
+  return NO;
+}
+
+BOOL nsCocoaUtils::ShouldRestoreStateDueToLaunchAtLogin() {
+  BOOL shouldRestore = ShouldRestoreStateDueToLaunchAtLoginImpl();
+  Telemetry::ScalarSet(Telemetry::ScalarID::STARTUP_IS_RESTORED_BY_MACOS,
+                       !!shouldRestore);
+  return shouldRestore;
+}
+
+void nsCocoaUtils::PrepareForNativeAppModalDialog() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Don't do anything if this is embedding. We'll assume that if there is no
+  // hidden window we shouldn't do anything, and that should cover the embedding
+  // case.
+  nsMenuBarX* hiddenWindowMenuBar = nsMenuUtilsX::GetHiddenWindowMenuBar();
+  if (!hiddenWindowMenuBar) return;
+
+  // First put up the hidden window menu bar so that app menu event handling is
+  // correct.
+  hiddenWindowMenuBar->Paint();
+
+  NSMenu* mainMenu = [NSApp mainMenu];
+  NS_ASSERTION(
+      [mainMenu numberOfItems] > 0,
+      "Main menu does not have any items, something is terribly wrong!");
+
+  // Create new menu bar for use with modal dialog
+  NSMenu* newMenuBar = [[NSMenu alloc] initWithTitle:@""];
+
+  // Swap in our app menu. Note that the event target is whatever window is up
+  // when the app modal dialog goes up.
+  NSMenuItem* firstMenuItem = [[mainMenu itemAtIndex:0] retain];
+  [mainMenu removeItemAtIndex:0];
+  [newMenuBar insertItem:firstMenuItem atIndex:0];
+  [firstMenuItem release];
+
+  // Add standard edit menu
+  [newMenuBar addItem:nsMenuUtilsX::GetStandardEditMenuItem()];
+
+  // Show the new menu bar
+  [NSApp setMainMenu:newMenuBar];
+  [newMenuBar release];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaUtils::CleanUpAfterNativeAppModalDialog() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Don't do anything if this is embedding. We'll assume that if there is no
+  // hidden window we shouldn't do anything, and that should cover the embedding
+  // case.
+  nsMenuBarX* hiddenWindowMenuBar = nsMenuUtilsX::GetHiddenWindowMenuBar();
+  if (!hiddenWindowMenuBar) return;
+
+  NSWindow* mainWindow = [NSApp mainWindow];
+  if (!mainWindow)
+    hiddenWindowMenuBar->Paint();
+  else
+    [WindowDelegate paintMenubarForWindow:mainWindow];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+static void data_ss_release_callback(void* aDataSourceSurface, const void* data,
+                                     size_t size) {
+  if (aDataSourceSurface) {
+    static_cast<DataSourceSurface*>(aDataSourceSurface)->Unmap();
+    static_cast<DataSourceSurface*>(aDataSourceSurface)->Release();
+  }
+}
+
+// This function assumes little endian byte order.
+static bool ComputeIsEntirelyBlack(const DataSourceSurface::MappedSurface& aMap,
+                                   const IntSize& aSize) {
+  for (int32_t y = 0; y < aSize.height; y++) {
+    size_t rowStart = y * aMap.mStride;
+    for (int32_t x = 0; x < aSize.width; x++) {
+      size_t index = rowStart + x * 4;
+      if (aMap.mData[index + 0] != 0 || aMap.mData[index + 1] != 0 ||
+          aMap.mData[index + 2] != 0) {
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
+nsresult nsCocoaUtils::CreateCGImageFromSurface(SourceSurface* aSurface,
+                                                CGImageRef* aResult,
+                                                bool* aIsEntirelyBlack) {
+  RefPtr<DataSourceSurface> dataSurface;
+
+  if (aSurface->GetFormat() == SurfaceFormat::B8G8R8A8) {
+    dataSurface = aSurface->GetDataSurface();
+  } else {
+    // CGImageCreate only supports 16- and 32-bit bit-depth
+    // Convert format to SurfaceFormat::B8G8R8A8
+    dataSurface = gfxUtils::CopySurfaceToDataSourceSurfaceWithFormat(
+        aSurface, SurfaceFormat::B8G8R8A8);
+  }
+
+  NS_ENSURE_TRUE(dataSurface, NS_ERROR_FAILURE);
+
+  int32_t width = dataSurface->GetSize().width;
+  int32_t height = dataSurface->GetSize().height;
+  if (height < 1 || width < 1) {
+    return NS_ERROR_FAILURE;
+  }
+
+  DataSourceSurface::MappedSurface map;
+  if (!dataSurface->Map(DataSourceSurface::MapType::READ, &map)) {
+    return NS_ERROR_FAILURE;
+  }
+  // The Unmap() call happens in data_ss_release_callback
+
+  if (aIsEntirelyBlack) {
+    *aIsEntirelyBlack = ComputeIsEntirelyBlack(map, dataSurface->GetSize());
+  }
+
+  // Create a CGImageRef with the bits from the image, taking into account
+  // the alpha ordering and endianness of the machine so we don't have to
+  // touch the bits ourselves.
+  CGDataProviderRef dataProvider = ::CGDataProviderCreateWithData(
+      dataSurface.forget().take(), map.mData, map.mStride * height,
+      data_ss_release_callback);
+  CGColorSpaceRef colorSpace =
+      ::CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);
+  *aResult = ::CGImageCreate(
+      width, height, 8, 32, map.mStride, colorSpace,
+      kCGBitmapByteOrder32Host | kCGImageAlphaPremultipliedFirst, dataProvider,
+      NULL, 0, kCGRenderingIntentDefault);
+  ::CGColorSpaceRelease(colorSpace);
+  ::CGDataProviderRelease(dataProvider);
+  return *aResult ? NS_OK : NS_ERROR_FAILURE;
+}
+
+nsresult nsCocoaUtils::CreateNSImageFromCGImage(CGImageRef aInputImage,
+                                                NSImage** aResult) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // Be very careful when creating the NSImage that the backing NSImageRep is
+  // exactly 1:1 with the input image. On a retina display, both [NSImage
+  // lockFocus] and [NSImage initWithCGImage:size:] will create an image with a
+  // 2x backing NSImageRep. This prevents NSCursor from recognizing a retina
+  // cursor, which only occurs if pixelsWide and pixelsHigh are exactly 2x the
+  // size of the NSImage.
+  //
+  // For example, if a 32x32 SVG cursor is rendered on a retina display, then
+  // aInputImage will be 64x64. The resulting NSImage will be scaled back down
+  // to 32x32 so it stays the correct size on the screen by changing its size
+  // (resizing a NSImage only scales the image and doesn't resample the data).
+  // If aInputImage is converted using [NSImage initWithCGImage:size:] then the
+  // bitmap will be 128x128 and NSCursor won't recognize a retina cursor, since
+  // it will expect a 64x64 bitmap.
+
+  int32_t width = ::CGImageGetWidth(aInputImage);
+  int32_t height = ::CGImageGetHeight(aInputImage);
+  NSRect imageRect = ::NSMakeRect(0.0, 0.0, width, height);
+
+  NSBitmapImageRep* offscreenRep = [[NSBitmapImageRep alloc]
+      initWithBitmapDataPlanes:NULL
+                    pixelsWide:width
+                    pixelsHigh:height
+                 bitsPerSample:8
+               samplesPerPixel:4
+                      hasAlpha:YES
+                      isPlanar:NO
+                colorSpaceName:NSDeviceRGBColorSpace
+                  bitmapFormat:NSBitmapFormatAlphaFirst
+                   bytesPerRow:0
+                  bitsPerPixel:0];
+
+  NSGraphicsContext* context =
+      [NSGraphicsContext graphicsContextWithBitmapImageRep:offscreenRep];
+  [NSGraphicsContext saveGraphicsState];
+  [NSGraphicsContext setCurrentContext:context];
+
+  // Get the Quartz context and draw.
+  CGContextRef imageContext = [[NSGraphicsContext currentContext] CGContext];
+  ::CGContextDrawImage(imageContext, *(CGRect*)&imageRect, aInputImage);
+
+  [NSGraphicsContext restoreGraphicsState];
+
+  *aResult = [[NSImage alloc] initWithSize:NSMakeSize(width, height)];
+  [*aResult addRepresentation:offscreenRep];
+  [offscreenRep release];
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+nsresult nsCocoaUtils::CreateNSImageFromImageContainer(
+    imgIContainer* aImage, uint32_t aWhichFrame,
+    const nsPresContext* aPresContext, const ComputedStyle* aComputedStyle,
+    NSImage** aResult, CGFloat scaleFactor, bool* aIsEntirelyBlack) {
+  RefPtr<SourceSurface> surface;
+  int32_t width = 0, height = 0;
+  aImage->GetWidth(&width);
+  aImage->GetHeight(&height);
+
+  // Render a vector image at the correct resolution on a retina display
+  if (aImage->GetType() == imgIContainer::TYPE_VECTOR) {
+    IntSize scaledSize =
+        IntSize::Ceil(width * scaleFactor, height * scaleFactor);
+
+    RefPtr<DrawTarget> drawTarget =
+        gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(
+            scaledSize, SurfaceFormat::B8G8R8A8);
+    if (!drawTarget || !drawTarget->IsValid()) {
+      NS_ERROR("Failed to create valid DrawTarget");
+      return NS_ERROR_FAILURE;
+    }
+
+    gfxContext context(drawTarget);
+
+    SVGImageContext svgContext;
+    if (aPresContext && aComputedStyle) {
+      SVGImageContext::MaybeStoreContextPaint(svgContext, *aPresContext,
+                                              *aComputedStyle, aImage);
+    }
+    mozilla::image::ImgDrawResult res =
+        aImage->Draw(&context, scaledSize, ImageRegion::Create(scaledSize),
+                     aWhichFrame, SamplingFilter::POINT, svgContext,
+                     imgIContainer::FLAG_SYNC_DECODE, 1.0);
+
+    if (res != mozilla::image::ImgDrawResult::SUCCESS) {
+      return NS_ERROR_FAILURE;
+    }
+
+    surface = drawTarget->Snapshot();
+  } else {
+    surface =
+        aImage->GetFrame(aWhichFrame, imgIContainer::FLAG_SYNC_DECODE |
+                                          imgIContainer::FLAG_ASYNC_NOTIFY);
+  }
+
+  NS_ENSURE_TRUE(surface, NS_ERROR_FAILURE);
+
+  CGImageRef imageRef = NULL;
+  nsresult rv = nsCocoaUtils::CreateCGImageFromSurface(surface, &imageRef,
+                                                       aIsEntirelyBlack);
+  if (NS_FAILED(rv) || !imageRef) {
+    return NS_ERROR_FAILURE;
+  }
+
+  rv = nsCocoaUtils::CreateNSImageFromCGImage(imageRef, aResult);
+  if (NS_FAILED(rv) || !aResult) {
+    return NS_ERROR_FAILURE;
+  }
+  ::CGImageRelease(imageRef);
+
+  // Ensure the image will be rendered the correct size on a retina display
+  NSSize size = NSMakeSize(width, height);
+  [*aResult setSize:size];
+  [[[*aResult representations] objectAtIndex:0] setSize:size];
+  return NS_OK;
+}
+
+nsresult nsCocoaUtils::CreateDualRepresentationNSImageFromImageContainer(
+    imgIContainer* aImage, uint32_t aWhichFrame,
+    const nsPresContext* aPresContext, const ComputedStyle* aComputedStyle,
+    NSImage** aResult, bool* aIsEntirelyBlack) {
+  int32_t width = 0, height = 0;
+  aImage->GetWidth(&width);
+  aImage->GetHeight(&height);
+  NSSize size = NSMakeSize(width, height);
+  *aResult = [[NSImage alloc] init];
+  [*aResult setSize:size];
+
+  NSImage* newRepresentation = nil;
+  nsresult rv = CreateNSImageFromImageContainer(
+      aImage, aWhichFrame, aPresContext, aComputedStyle, &newRepresentation,
+      1.0f, aIsEntirelyBlack);
+  if (NS_FAILED(rv) || !newRepresentation) {
+    return NS_ERROR_FAILURE;
+  }
+
+  [[[newRepresentation representations] objectAtIndex:0] setSize:size];
+  [*aResult
+      addRepresentation:[[newRepresentation representations] objectAtIndex:0]];
+  [newRepresentation release];
+  newRepresentation = nil;
+
+  rv = CreateNSImageFromImageContainer(aImage, aWhichFrame, aPresContext,
+                                       aComputedStyle, &newRepresentation, 2.0f,
+                                       aIsEntirelyBlack);
+  if (NS_FAILED(rv) || !newRepresentation) {
+    return NS_ERROR_FAILURE;
+  }
+
+  [[[newRepresentation representations] objectAtIndex:0] setSize:size];
+  [*aResult
+      addRepresentation:[[newRepresentation representations] objectAtIndex:0]];
+  [newRepresentation release];
+  return NS_OK;
+}
+
+// static
+void nsCocoaUtils::GetStringForNSString(const NSString* aSrc,
+                                        nsAString& aDist) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!aSrc) {
+    aDist.Truncate();
+    return;
+  }
+
+  aDist.SetLength([aSrc length]);
+  [aSrc getCharacters:reinterpret_cast<unichar*>(aDist.BeginWriting())
+                range:NSMakeRange(0, [aSrc length])];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// static
+NSString* nsCocoaUtils::ToNSString(const nsAString& aString) {
+  if (aString.IsEmpty()) {
+    return [NSString string];
+  }
+  return [NSString stringWithCharacters:reinterpret_cast<const unichar*>(
+                                            aString.BeginReading())
+                                 length:aString.Length()];
+}
+
+// static
+NSString* nsCocoaUtils::ToNSString(const nsACString& aCString) {
+  if (aCString.IsEmpty()) {
+    return [NSString string];
+  }
+  return [[[NSString alloc] initWithBytes:aCString.BeginReading()
+                                   length:aCString.Length()
+                                 encoding:NSUTF8StringEncoding] autorelease];
+}
+
+// static
+NSURL* nsCocoaUtils::ToNSURL(const nsAString& aURLString) {
+  nsAutoCString encodedURLString;
+  nsresult rv = NS_GetSpecWithNSURLEncoding(encodedURLString,
+                                            NS_ConvertUTF16toUTF8(aURLString));
+  NS_ENSURE_SUCCESS(rv, nullptr);
+
+  NSString* encodedURLNSString = ToNSString(encodedURLString);
+  if (!encodedURLNSString) {
+    return nullptr;
+  }
+
+  return [NSURL URLWithString:encodedURLNSString];
+}
+
+// static
+void nsCocoaUtils::GeckoRectToNSRect(const nsIntRect& aGeckoRect,
+                                     NSRect& aOutCocoaRect) {
+  aOutCocoaRect.origin.x = aGeckoRect.x;
+  aOutCocoaRect.origin.y = aGeckoRect.y;
+  aOutCocoaRect.size.width = aGeckoRect.width;
+  aOutCocoaRect.size.height = aGeckoRect.height;
+}
+
+// static
+void nsCocoaUtils::NSRectToGeckoRect(const NSRect& aCocoaRect,
+                                     nsIntRect& aOutGeckoRect) {
+  aOutGeckoRect.x = NSToIntRound(aCocoaRect.origin.x);
+  aOutGeckoRect.y = NSToIntRound(aCocoaRect.origin.y);
+  aOutGeckoRect.width =
+      NSToIntRound(aCocoaRect.origin.x + aCocoaRect.size.width) -
+      aOutGeckoRect.x;
+  aOutGeckoRect.height =
+      NSToIntRound(aCocoaRect.origin.y + aCocoaRect.size.height) -
+      aOutGeckoRect.y;
+}
+
+// static
+NSEvent* nsCocoaUtils::MakeNewCocoaEventWithType(NSEventType aEventType,
+                                                 NSEvent* aEvent) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSEvent* newEvent =
+      [NSEvent keyEventWithType:aEventType
+                             location:[aEvent locationInWindow]
+                        modifierFlags:[aEvent modifierFlags]
+                            timestamp:[aEvent timestamp]
+                         windowNumber:[aEvent windowNumber]
+                              context:nil
+                           characters:[aEvent characters]
+          charactersIgnoringModifiers:[aEvent charactersIgnoringModifiers]
+                            isARepeat:[aEvent isARepeat]
+                              keyCode:[aEvent keyCode]];
+  return newEvent;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+// static
+NSEvent* nsCocoaUtils::MakeNewCococaEventFromWidgetEvent(
+    const WidgetKeyboardEvent& aKeyEvent, NSInteger aWindowNumber,
+    NSGraphicsContext* aContext) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSEventType eventType;
+  if (aKeyEvent.mMessage == eKeyUp) {
+    eventType = NSEventTypeKeyUp;
+  } else {
+    eventType = NSEventTypeKeyDown;
+  }
+
+  static const uint32_t sModifierFlagMap[][2] = {
+      {MODIFIER_SHIFT, NSEventModifierFlagShift},
+      {MODIFIER_CONTROL, NSEventModifierFlagControl},
+      {MODIFIER_ALT, NSEventModifierFlagOption},
+      {MODIFIER_ALTGRAPH, NSEventModifierFlagOption},
+      {MODIFIER_META, NSEventModifierFlagCommand},
+      {MODIFIER_CAPSLOCK, NSEventModifierFlagCapsLock},
+      {MODIFIER_NUMLOCK, NSEventModifierFlagNumericPad}};
+
+  NSUInteger modifierFlags = 0;
+  for (uint32_t i = 0; i < ArrayLength(sModifierFlagMap); ++i) {
+    if (aKeyEvent.mModifiers & sModifierFlagMap[i][0]) {
+      modifierFlags |= sModifierFlagMap[i][1];
+    }
+  }
+
+  NSString* characters;
+  if (aKeyEvent.mCharCode) {
+    characters =
+        [NSString stringWithCharacters:reinterpret_cast<const unichar*>(
+                                           &(aKeyEvent.mCharCode))
+                                length:1];
+  } else {
+    uint32_t cocoaCharCode =
+        nsCocoaUtils::ConvertGeckoKeyCodeToMacCharCode(aKeyEvent.mKeyCode);
+    characters = [NSString
+        stringWithCharacters:reinterpret_cast<const unichar*>(&cocoaCharCode)
+                      length:1];
+  }
+
+  return [NSEvent keyEventWithType:eventType
+                          location:NSMakePoint(0, 0)
+                     modifierFlags:modifierFlags
+                         timestamp:0
+                      windowNumber:aWindowNumber
+                           context:aContext
+                        characters:characters
+       charactersIgnoringModifiers:characters
+                         isARepeat:NO
+                           keyCode:0];  // Native key code not currently needed
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+// static
+void nsCocoaUtils::InitInputEvent(WidgetInputEvent& aInputEvent,
+                                  NSEvent* aNativeEvent) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  aInputEvent.mModifiers = ModifiersForEvent(aNativeEvent);
+  aInputEvent.mTimeStamp = GetEventTimeStamp([aNativeEvent timestamp]);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// static
+Modifiers nsCocoaUtils::ModifiersForEvent(NSEvent* aNativeEvent) {
+  NSUInteger modifiers =
+      aNativeEvent ? [aNativeEvent modifierFlags] : [NSEvent modifierFlags];
+  Modifiers result = 0;
+  if (modifiers & NSEventModifierFlagShift) {
+    result |= MODIFIER_SHIFT;
+  }
+  if (modifiers & NSEventModifierFlagControl) {
+    result |= MODIFIER_CONTROL;
+  }
+  if (modifiers & NSEventModifierFlagOption) {
+    result |= MODIFIER_ALT;
+    // Mac's option key is similar to other platforms' AltGr key.
+    // Let's set AltGr flag when option key is pressed for consistency with
+    // other platforms.
+    result |= MODIFIER_ALTGRAPH;
+  }
+  if (modifiers & NSEventModifierFlagCommand) {
+    result |= MODIFIER_META;
+  }
+
+  if (modifiers & NSEventModifierFlagCapsLock) {
+    result |= MODIFIER_CAPSLOCK;
+  }
+  // Mac doesn't have NumLock key.  We can assume that NumLock is always locked
+  // if user is using a keyboard which has numpad.  Otherwise, if user is using
+  // a keyboard which doesn't have numpad, e.g., MacBook's keyboard, we can
+  // assume that NumLock is always unlocked.
+  // Unfortunately, we cannot know whether current keyboard has numpad or not.
+  // We should notify locked state only when keys in numpad are pressed.
+  // By this, web applications may not be confused by unexpected numpad key's
+  // key event with unlocked state.
+  if (modifiers & NSEventModifierFlagNumericPad) {
+    result |= MODIFIER_NUMLOCK;
+  }
+
+  // Be aware, NSEventModifierFlagFunction is included when arrow keys, home key
+  // or some other keys are pressed. We cannot check whether 'fn' key is pressed
+  // or not by the flag.
+
+  return result;
+}
+
+// static
+UInt32 nsCocoaUtils::ConvertToCarbonModifier(NSUInteger aCocoaModifier) {
+  UInt32 carbonModifier = 0;
+  if (aCocoaModifier & NSEventModifierFlagCapsLock) {
+    carbonModifier |= alphaLock;
+  }
+  if (aCocoaModifier & NSEventModifierFlagControl) {
+    carbonModifier |= controlKey;
+  }
+  if (aCocoaModifier & NSEventModifierFlagOption) {
+    carbonModifier |= optionKey;
+  }
+  if (aCocoaModifier & NSEventModifierFlagShift) {
+    carbonModifier |= shiftKey;
+  }
+  if (aCocoaModifier & NSEventModifierFlagCommand) {
+    carbonModifier |= cmdKey;
+  }
+  if (aCocoaModifier & NSEventModifierFlagNumericPad) {
+    carbonModifier |= kEventKeyModifierNumLockMask;
+  }
+  if (aCocoaModifier & NSEventModifierFlagFunction) {
+    carbonModifier |= kEventKeyModifierFnMask;
+  }
+  return carbonModifier;
+}
+
+// While HiDPI support is not 100% complete and tested, we'll have a pref
+// to allow it to be turned off in case of problems (or for testing purposes).
+
+// gfx.hidpi.enabled is an integer with the meaning:
+//    <= 0 : HiDPI support is disabled
+//       1 : HiDPI enabled provided all screens have the same backing resolution
+//     > 1 : HiDPI enabled even if there are a mixture of screen modes
+
+// All the following code is to be removed once HiDPI work is more complete.
+
+static bool sHiDPIEnabled = false;
+static bool sHiDPIPrefInitialized = false;
+
+// static
+bool nsCocoaUtils::HiDPIEnabled() {
+  if (!sHiDPIPrefInitialized) {
+    sHiDPIPrefInitialized = true;
+
+    int prefSetting = Preferences::GetInt("gfx.hidpi.enabled", 1);
+    if (prefSetting <= 0) {
+      return false;
+    }
+
+    // prefSetting is at least 1, need to check attached screens...
+
+    int scaleFactors = 0;  // used as a bitset to track the screen types found
+    NSEnumerator* screenEnum = [[NSScreen screens] objectEnumerator];
+    while (NSScreen* screen = [screenEnum nextObject]) {
+      NSDictionary* desc = [screen deviceDescription];
+      if ([desc objectForKey:NSDeviceIsScreen] == nil) {
+        continue;
+      }
+      // Currently, we only care about differentiating "1.0" and "2.0",
+      // so we set one of the two low bits to record which.
+      if ([screen backingScaleFactor] > 1.0) {
+        scaleFactors |= 2;
+      } else {
+        scaleFactors |= 1;
+      }
+    }
+
+    // Now scaleFactors will be:
+    //   0 if no screens (supporting backingScaleFactor) found
+    //   1 if only lo-DPI screens
+    //   2 if only hi-DPI screens
+    //   3 if both lo- and hi-DPI screens
+    // We'll enable HiDPI support if there's only a single screen type,
+    // OR if the pref setting is explicitly greater than 1.
+    sHiDPIEnabled = (scaleFactors <= 2) || (prefSetting > 1);
+  }
+
+  return sHiDPIEnabled;
+}
+
+// static
+void nsCocoaUtils::InvalidateHiDPIState() { sHiDPIPrefInitialized = false; }
+
+void nsCocoaUtils::GetCommandsFromKeyEvent(
+    NSEvent* aEvent, nsTArray<KeyBindingsCommand>& aCommands) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  MOZ_ASSERT(aEvent);
+
+  static NativeKeyBindingsRecorder* sNativeKeyBindingsRecorder;
+  if (!sNativeKeyBindingsRecorder) {
+    sNativeKeyBindingsRecorder = [NativeKeyBindingsRecorder new];
+  }
+
+  [sNativeKeyBindingsRecorder startRecording:aCommands];
+
+  // This will trigger 0 - N calls to doCommandBySelector: and insertText:
+  [sNativeKeyBindingsRecorder
+      interpretKeyEvents:[NSArray arrayWithObject:aEvent]];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+@implementation NativeKeyBindingsRecorder
+
+- (void)startRecording:(nsTArray<KeyBindingsCommand>&)aCommands {
+  mCommands = &aCommands;
+  mCommands->Clear();
+}
+
+- (void)doCommandBySelector:(SEL)aSelector {
+  KeyBindingsCommand command = {aSelector, nil};
+
+  mCommands->AppendElement(command);
+}
+
+- (void)insertText:(id)aString {
+  KeyBindingsCommand command = {@selector(insertText:), aString};
+
+  mCommands->AppendElement(command);
+}
+
+@end  // NativeKeyBindingsRecorder
+
+struct KeyConversionData {
+  const char* str;
+  size_t strLength;
+  uint32_t geckoKeyCode;
+  uint32_t charCode;
+};
+
+static const KeyConversionData gKeyConversions[] = {
+
+#define KEYCODE_ENTRY(aStr, aCode) \
+  { #aStr, sizeof(#aStr) - 1, NS_##aStr, aCode }
+
+// Some keycodes may have different name in KeyboardEvent from its key name.
+#define KEYCODE_ENTRY2(aStr, aNSName, aCode) \
+  { #aStr, sizeof(#aStr) - 1, NS_##aNSName, aCode }
+
+    KEYCODE_ENTRY(VK_CANCEL, 0x001B),
+    KEYCODE_ENTRY(VK_DELETE, NSDeleteFunctionKey),
+    KEYCODE_ENTRY(VK_BACK, NSBackspaceCharacter),
+    KEYCODE_ENTRY2(VK_BACK_SPACE, VK_BACK, NSBackspaceCharacter),
+    KEYCODE_ENTRY(VK_TAB, NSTabCharacter),
+    KEYCODE_ENTRY(VK_CLEAR, NSClearLineFunctionKey),
+    KEYCODE_ENTRY(VK_RETURN, NSEnterCharacter),
+    KEYCODE_ENTRY(VK_SHIFT, 0),
+    KEYCODE_ENTRY(VK_CONTROL, 0),
+    KEYCODE_ENTRY(VK_ALT, 0),
+    KEYCODE_ENTRY(VK_PAUSE, NSPauseFunctionKey),
+    KEYCODE_ENTRY(VK_CAPS_LOCK, 0),
+    KEYCODE_ENTRY(VK_ESCAPE, 0),
+    KEYCODE_ENTRY(VK_SPACE, ' '),
+    KEYCODE_ENTRY(VK_PAGE_UP, NSPageUpFunctionKey),
+    KEYCODE_ENTRY(VK_PAGE_DOWN, NSPageDownFunctionKey),
+    KEYCODE_ENTRY(VK_END, NSEndFunctionKey),
+    KEYCODE_ENTRY(VK_HOME, NSHomeFunctionKey),
+    KEYCODE_ENTRY(VK_LEFT, NSLeftArrowFunctionKey),
+    KEYCODE_ENTRY(VK_UP, NSUpArrowFunctionKey),
+    KEYCODE_ENTRY(VK_RIGHT, NSRightArrowFunctionKey),
+    KEYCODE_ENTRY(VK_DOWN, NSDownArrowFunctionKey),
+    KEYCODE_ENTRY(VK_PRINTSCREEN, NSPrintScreenFunctionKey),
+    KEYCODE_ENTRY(VK_INSERT, NSInsertFunctionKey),
+    KEYCODE_ENTRY(VK_HELP, NSHelpFunctionKey),
+    KEYCODE_ENTRY(VK_0, '0'),
+    KEYCODE_ENTRY(VK_1, '1'),
+    KEYCODE_ENTRY(VK_2, '2'),
+    KEYCODE_ENTRY(VK_3, '3'),
+    KEYCODE_ENTRY(VK_4, '4'),
+    KEYCODE_ENTRY(VK_5, '5'),
+    KEYCODE_ENTRY(VK_6, '6'),
+    KEYCODE_ENTRY(VK_7, '7'),
+    KEYCODE_ENTRY(VK_8, '8'),
+    KEYCODE_ENTRY(VK_9, '9'),
+    KEYCODE_ENTRY(VK_SEMICOLON, ':'),
+    KEYCODE_ENTRY(VK_EQUALS, '='),
+    KEYCODE_ENTRY(VK_A, 'A'),
+    KEYCODE_ENTRY(VK_B, 'B'),
+    KEYCODE_ENTRY(VK_C, 'C'),
+    KEYCODE_ENTRY(VK_D, 'D'),
+    KEYCODE_ENTRY(VK_E, 'E'),
+    KEYCODE_ENTRY(VK_F, 'F'),
+    KEYCODE_ENTRY(VK_G, 'G'),
+    KEYCODE_ENTRY(VK_H, 'H'),
+    KEYCODE_ENTRY(VK_I, 'I'),
+    KEYCODE_ENTRY(VK_J, 'J'),
+    KEYCODE_ENTRY(VK_K, 'K'),
+    KEYCODE_ENTRY(VK_L, 'L'),
+    KEYCODE_ENTRY(VK_M, 'M'),
+    KEYCODE_ENTRY(VK_N, 'N'),
+    KEYCODE_ENTRY(VK_O, 'O'),
+    KEYCODE_ENTRY(VK_P, 'P'),
+    KEYCODE_ENTRY(VK_Q, 'Q'),
+    KEYCODE_ENTRY(VK_R, 'R'),
+    KEYCODE_ENTRY(VK_S, 'S'),
+    KEYCODE_ENTRY(VK_T, 'T'),
+    KEYCODE_ENTRY(VK_U, 'U'),
+    KEYCODE_ENTRY(VK_V, 'V'),
+    KEYCODE_ENTRY(VK_W, 'W'),
+    KEYCODE_ENTRY(VK_X, 'X'),
+    KEYCODE_ENTRY(VK_Y, 'Y'),
+    KEYCODE_ENTRY(VK_Z, 'Z'),
+    KEYCODE_ENTRY(VK_CONTEXT_MENU, NSMenuFunctionKey),
+    KEYCODE_ENTRY(VK_NUMPAD0, '0'),
+    KEYCODE_ENTRY(VK_NUMPAD1, '1'),
+    KEYCODE_ENTRY(VK_NUMPAD2, '2'),
+    KEYCODE_ENTRY(VK_NUMPAD3, '3'),
+    KEYCODE_ENTRY(VK_NUMPAD4, '4'),
+    KEYCODE_ENTRY(VK_NUMPAD5, '5'),
+    KEYCODE_ENTRY(VK_NUMPAD6, '6'),
+    KEYCODE_ENTRY(VK_NUMPAD7, '7'),
+    KEYCODE_ENTRY(VK_NUMPAD8, '8'),
+    KEYCODE_ENTRY(VK_NUMPAD9, '9'),
+    KEYCODE_ENTRY(VK_MULTIPLY, '*'),
+    KEYCODE_ENTRY(VK_ADD, '+'),
+    KEYCODE_ENTRY(VK_SEPARATOR, 0),
+    KEYCODE_ENTRY(VK_SUBTRACT, '-'),
+    KEYCODE_ENTRY(VK_DECIMAL, '.'),
+    KEYCODE_ENTRY(VK_DIVIDE, '/'),
+    KEYCODE_ENTRY(VK_F1, NSF1FunctionKey),
+    KEYCODE_ENTRY(VK_F2, NSF2FunctionKey),
+    KEYCODE_ENTRY(VK_F3, NSF3FunctionKey),
+    KEYCODE_ENTRY(VK_F4, NSF4FunctionKey),
+    KEYCODE_ENTRY(VK_F5, NSF5FunctionKey),
+    KEYCODE_ENTRY(VK_F6, NSF6FunctionKey),
+    KEYCODE_ENTRY(VK_F7, NSF7FunctionKey),
+    KEYCODE_ENTRY(VK_F8, NSF8FunctionKey),
+    KEYCODE_ENTRY(VK_F9, NSF9FunctionKey),
+    KEYCODE_ENTRY(VK_F10, NSF10FunctionKey),
+    KEYCODE_ENTRY(VK_F11, NSF11FunctionKey),
+    KEYCODE_ENTRY(VK_F12, NSF12FunctionKey),
+    KEYCODE_ENTRY(VK_F13, NSF13FunctionKey),
+    KEYCODE_ENTRY(VK_F14, NSF14FunctionKey),
+    KEYCODE_ENTRY(VK_F15, NSF15FunctionKey),
+    KEYCODE_ENTRY(VK_F16, NSF16FunctionKey),
+    KEYCODE_ENTRY(VK_F17, NSF17FunctionKey),
+    KEYCODE_ENTRY(VK_F18, NSF18FunctionKey),
+    KEYCODE_ENTRY(VK_F19, NSF19FunctionKey),
+    KEYCODE_ENTRY(VK_F20, NSF20FunctionKey),
+    KEYCODE_ENTRY(VK_F21, NSF21FunctionKey),
+    KEYCODE_ENTRY(VK_F22, NSF22FunctionKey),
+    KEYCODE_ENTRY(VK_F23, NSF23FunctionKey),
+    KEYCODE_ENTRY(VK_F24, NSF24FunctionKey),
+    KEYCODE_ENTRY(VK_NUM_LOCK, NSClearLineFunctionKey),
+    KEYCODE_ENTRY(VK_SCROLL_LOCK, NSScrollLockFunctionKey),
+    KEYCODE_ENTRY(VK_COMMA, ','),
+    KEYCODE_ENTRY(VK_PERIOD, '.'),
+    KEYCODE_ENTRY(VK_SLASH, '/'),
+    KEYCODE_ENTRY(VK_BACK_QUOTE, '`'),
+    KEYCODE_ENTRY(VK_OPEN_BRACKET, '['),
+    KEYCODE_ENTRY(VK_BACK_SLASH, '\\'),
+    KEYCODE_ENTRY(VK_CLOSE_BRACKET, ']'),
+    KEYCODE_ENTRY(VK_QUOTE, '\'')
+
+#undef KEYCODE_ENTRY
+
+};
+
+uint32_t nsCocoaUtils::ConvertGeckoNameToMacCharCode(
+    const nsAString& aKeyCodeName) {
+  if (aKeyCodeName.IsEmpty()) {
+    return 0;
+  }
+
+  nsAutoCString keyCodeName;
+  LossyCopyUTF16toASCII(aKeyCodeName, keyCodeName);
+  // We want case-insensitive comparison with data stored as uppercase.
+  ToUpperCase(keyCodeName);
+
+  uint32_t keyCodeNameLength = keyCodeName.Length();
+  const char* keyCodeNameStr = keyCodeName.get();
+  for (uint16_t i = 0; i < ArrayLength(gKeyConversions); ++i) {
+    if (keyCodeNameLength == gKeyConversions[i].strLength &&
+        nsCRT::strcmp(gKeyConversions[i].str, keyCodeNameStr) == 0) {
+      return gKeyConversions[i].charCode;
+    }
+  }
+
+  return 0;
+}
+
+uint32_t nsCocoaUtils::ConvertGeckoKeyCodeToMacCharCode(uint32_t aKeyCode) {
+  if (!aKeyCode) {
+    return 0;
+  }
+
+  for (uint16_t i = 0; i < ArrayLength(gKeyConversions); ++i) {
+    if (gKeyConversions[i].geckoKeyCode == aKeyCode) {
+      return gKeyConversions[i].charCode;
+    }
+  }
+
+  return 0;
+}
+
+NSEventModifierFlags nsCocoaUtils::ConvertWidgetModifiersToMacModifierFlags(
+    nsIWidget::Modifiers aNativeModifiers) {
+  if (!aNativeModifiers) {
+    return 0;
+  }
+  struct ModifierFlagMapEntry {
+    nsIWidget::Modifiers mWidgetModifier;
+    NSEventModifierFlags mModifierFlags;
+  };
+  static constexpr ModifierFlagMapEntry sModifierFlagMap[] = {
+      {nsIWidget::CAPS_LOCK, NSEventModifierFlagCapsLock},
+      {nsIWidget::SHIFT_L, NSEventModifierFlagShift | 0x0002},
+      {nsIWidget::SHIFT_R, NSEventModifierFlagShift | 0x0004},
+      {nsIWidget::CTRL_L, NSEventModifierFlagControl | 0x0001},
+      {nsIWidget::CTRL_R, NSEventModifierFlagControl | 0x2000},
+      {nsIWidget::ALT_L, NSEventModifierFlagOption | 0x0020},
+      {nsIWidget::ALT_R, NSEventModifierFlagOption | 0x0040},
+      {nsIWidget::COMMAND_L, NSEventModifierFlagCommand | 0x0008},
+      {nsIWidget::COMMAND_R, NSEventModifierFlagCommand | 0x0010},
+      {nsIWidget::NUMERIC_KEY_PAD, NSEventModifierFlagNumericPad},
+      {nsIWidget::HELP, NSEventModifierFlagHelp},
+      {nsIWidget::FUNCTION, NSEventModifierFlagFunction}};
+
+  NSEventModifierFlags modifierFlags = 0;
+  for (const ModifierFlagMapEntry& entry : sModifierFlagMap) {
+    if (aNativeModifiers & entry.mWidgetModifier) {
+      modifierFlags |= entry.mModifierFlags;
+    }
+  }
+  return modifierFlags;
+}
+
+mozilla::MouseButton nsCocoaUtils::ButtonForEvent(NSEvent* aEvent) {
+  switch (aEvent.type) {
+    case NSEventTypeLeftMouseDown:
+    case NSEventTypeLeftMouseDragged:
+    case NSEventTypeLeftMouseUp:
+      return MouseButton::ePrimary;
+    case NSEventTypeRightMouseDown:
+    case NSEventTypeRightMouseDragged:
+    case NSEventTypeRightMouseUp:
+      return MouseButton::eSecondary;
+    case NSEventTypeOtherMouseDown:
+    case NSEventTypeOtherMouseDragged:
+    case NSEventTypeOtherMouseUp:
+      switch (aEvent.buttonNumber) {
+        case 3:
+          return MouseButton::eX1;
+        case 4:
+          return MouseButton::eX2;
+        default:
+          // The middle button usually has button 2, but if this is a
+          // synthesized event (for which you cannot specify a buttonNumber),
+          // then the button will be 0. Treat all remaining OtherMouse events as
+          // the middle button.
+          return MouseButton::eMiddle;
+      }
+    default:
+      // Treat non-mouse events as the primary mouse button.
+      return MouseButton::ePrimary;
+  }
+}
+
+NSMutableAttributedString* nsCocoaUtils::GetNSMutableAttributedString(
+    const nsAString& aText, const nsTArray<mozilla::FontRange>& aFontRanges,
+    const bool aIsVertical, const CGFloat aBackingScaleFactor) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+
+  NSString* nsstr = nsCocoaUtils::ToNSString(aText);
+  NSMutableAttributedString* attrStr =
+      [[[NSMutableAttributedString alloc] initWithString:nsstr
+                                              attributes:nil] autorelease];
+
+  int32_t lastOffset = aText.Length();
+  for (auto i = aFontRanges.Length(); i > 0; --i) {
+    const FontRange& fontRange = aFontRanges[i - 1];
+    NSString* fontName = nsCocoaUtils::ToNSString(fontRange.mFontName);
+    CGFloat fontSize = fontRange.mFontSize / aBackingScaleFactor;
+    NSFont* font = [NSFont fontWithName:fontName size:fontSize];
+    if (!font) {
+      font = [NSFont systemFontOfSize:fontSize];
+    }
+
+    NSDictionary* attrs = @{NSFontAttributeName : font};
+    NSRange range = NSMakeRange(fontRange.mStartOffset,
+                                lastOffset - fontRange.mStartOffset);
+    [attrStr setAttributes:attrs range:range];
+    lastOffset = fontRange.mStartOffset;
+  }
+
+  if (aIsVertical) {
+    [attrStr addAttribute:NSVerticalGlyphFormAttributeName
+                    value:[NSNumber numberWithInt:1]
+                    range:NSMakeRange(0, [attrStr length])];
+  }
+
+  return attrStr;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil)
+}
+
+TimeStamp nsCocoaUtils::GetEventTimeStamp(NSTimeInterval aEventTime) {
+  if (!aEventTime) {
+    // If the event is generated by a 3rd party application, its timestamp
+    // may be 0.  In this case, just return current timestamp.
+    // XXX Should we cache last event time?
+    return TimeStamp::Now();
+  }
+  // The internal value of the macOS implementation of TimeStamp is based on
+  // mach_absolute_time(), which measures "ticks" since boot.
+  // Event timestamps are NSTimeIntervals (seconds) since boot. So the two time
+  // representations already have the same base; we only need to convert
+  // seconds into ticks.
+  int64_t tick =
+      BaseTimeDurationPlatformUtils::TicksFromMilliseconds(aEventTime * 1000.0);
+  return TimeStamp::FromSystemTime(tick);
+}
+
+static NSString* ActionOnDoubleClickSystemPref() {
+  NSUserDefaults* userDefaults = [NSUserDefaults standardUserDefaults];
+  NSString* kAppleActionOnDoubleClickKey = @"AppleActionOnDoubleClick";
+  id value = [userDefaults objectForKey:kAppleActionOnDoubleClickKey];
+  if ([value isKindOfClass:[NSString class]]) {
+    return value;
+  }
+  return nil;
+}
+
+@interface NSWindow (NSWindowShouldZoomOnDoubleClick)
++ (BOOL)_shouldZoomOnDoubleClick;  // present on 10.7 and above
+@end
+
+bool nsCocoaUtils::ShouldZoomOnTitlebarDoubleClick() {
+  if ([NSWindow respondsToSelector:@selector(_shouldZoomOnDoubleClick)]) {
+    return [NSWindow _shouldZoomOnDoubleClick];
+  }
+  return [ActionOnDoubleClickSystemPref() isEqualToString:@"Maximize"];
+}
+
+bool nsCocoaUtils::ShouldMinimizeOnTitlebarDoubleClick() {
+  // Check the system preferences.
+  // We could also check -[NSWindow _shouldMiniaturizeOnDoubleClick]. It's not
+  // clear to me which approach would be preferable; neither is public API.
+  return [ActionOnDoubleClickSystemPref() isEqualToString:@"Minimize"];
+}
+
+static const char* AVMediaTypeToString(AVMediaType aType) {
+  if (aType == AVMediaTypeVideo) {
+    return "video";
+  }
+
+  if (aType == AVMediaTypeAudio) {
+    return "audio";
+  }
+
+  return "unexpected type";
+}
+
+static void LogAuthorizationStatus(AVMediaType aType, int aState) {
+  const char* stateString;
+
+  switch (aState) {
+    case AVAuthorizationStatusAuthorized:
+      stateString = "AVAuthorizationStatusAuthorized";
+      break;
+    case AVAuthorizationStatusDenied:
+      stateString = "AVAuthorizationStatusDenied";
+      break;
+    case AVAuthorizationStatusNotDetermined:
+      stateString = "AVAuthorizationStatusNotDetermined";
+      break;
+    case AVAuthorizationStatusRestricted:
+      stateString = "AVAuthorizationStatusRestricted";
+      break;
+    default:
+      stateString = "Invalid state";
+  }
+
+  LOG("%s authorization status: %s\n", AVMediaTypeToString(aType), stateString);
+}
+
+static nsresult GetPermissionState(AVMediaType aMediaType, uint16_t& aState) {
+  MOZ_ASSERT(aMediaType == AVMediaTypeVideo || aMediaType == AVMediaTypeAudio);
+
+  AVAuthorizationStatus authStatus = static_cast<AVAuthorizationStatus>(
+      [AVCaptureDevice authorizationStatusForMediaType:aMediaType]);
+  LogAuthorizationStatus(aMediaType, authStatus);
+
+  // Convert AVAuthorizationStatus to nsIOSPermissionRequest const
+  switch (authStatus) {
+    case AVAuthorizationStatusAuthorized:
+      aState = nsIOSPermissionRequest::PERMISSION_STATE_AUTHORIZED;
+      return NS_OK;
+    case AVAuthorizationStatusDenied:
+      aState = nsIOSPermissionRequest::PERMISSION_STATE_DENIED;
+      return NS_OK;
+    case AVAuthorizationStatusNotDetermined:
+      aState = nsIOSPermissionRequest::PERMISSION_STATE_NOTDETERMINED;
+      return NS_OK;
+    case AVAuthorizationStatusRestricted:
+      aState = nsIOSPermissionRequest::PERMISSION_STATE_RESTRICTED;
+      return NS_OK;
+    default:
+      MOZ_ASSERT(false, "Invalid authorization status");
+      return NS_ERROR_UNEXPECTED;
+  }
+}
+
+nsresult nsCocoaUtils::GetVideoCapturePermissionState(
+    uint16_t& aPermissionState) {
+  return GetPermissionState(AVMediaTypeVideo, aPermissionState);
+}
+
+nsresult nsCocoaUtils::GetAudioCapturePermissionState(
+    uint16_t& aPermissionState) {
+  return GetPermissionState(AVMediaTypeAudio, aPermissionState);
+}
+
+// Set |aPermissionState| to PERMISSION_STATE_AUTHORIZED if this application
+// has already been granted permission to record the screen in macOS Security
+// and Privacy system settings. If we do not have permission (because the user
+// hasn't yet been asked yet or the user previously denied the prompt), use
+// PERMISSION_STATE_DENIED. Returns NS_ERROR_NOT_IMPLEMENTED on macOS 10.14
+// and earlier.
+nsresult nsCocoaUtils::GetScreenCapturePermissionState(
+    uint16_t& aPermissionState) {
+  aPermissionState = nsIOSPermissionRequest::PERMISSION_STATE_NOTDETERMINED;
+
+  if (!StaticPrefs::media_macos_screenrecording_oscheck_enabled()) {
+    aPermissionState = nsIOSPermissionRequest::PERMISSION_STATE_AUTHORIZED;
+    LOG("screen authorization status: authorized (test disabled via pref)");
+    return NS_OK;
+  }
+
+  // Unlike with camera and microphone capture, there is no support for
+  // checking the screen recording permission status. Instead, an application
+  // can use the presence of window names (which are privacy sensitive) in
+  // the window info list as an indication. The list only includes window
+  // names if the calling application has been authorized to record the
+  // screen. We use the window name, window level, and owning PID as
+  // heuristics to determine if we have screen recording permission.
+  AutoCFRelease<CFArrayRef> windowArray =
+      CGWindowListCopyWindowInfo(kCGWindowListOptionAll, kCGNullWindowID);
+  if (!windowArray) {
+    LOG("GetScreenCapturePermissionState() ERROR: got NULL window info list");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  int32_t windowLevelDock = CGWindowLevelForKey(kCGDockWindowLevelKey);
+  int32_t windowLevelNormal = CGWindowLevelForKey(kCGNormalWindowLevelKey);
+  LOG("GetScreenCapturePermissionState(): DockWindowLevel: %d, "
+      "NormalWindowLevel: %d",
+      windowLevelDock, windowLevelNormal);
+
+  int32_t thisPid = [[NSProcessInfo processInfo] processIdentifier];
+
+  CFIndex windowCount = CFArrayGetCount(windowArray);
+  LOG("GetScreenCapturePermissionState() returned %ld windows", windowCount);
+  if (windowCount == 0) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  for (CFIndex i = 0; i < windowCount; i++) {
+    CFDictionaryRef windowDict = reinterpret_cast<CFDictionaryRef>(
+        CFArrayGetValueAtIndex(windowArray, i));
+
+    // Get the window owner's PID
+    int32_t windowOwnerPid = -1;
+    CFNumberRef windowPidRef = reinterpret_cast<CFNumberRef>(
+        CFDictionaryGetValue(windowDict, kCGWindowOwnerPID));
+    if (!windowPidRef ||
+        !CFNumberGetValue(windowPidRef, kCFNumberIntType, &windowOwnerPid)) {
+      LOG("GetScreenCapturePermissionState() ERROR: failed to get window "
+          "owner");
+      continue;
+    }
+
+    // Our own window names are always readable and
+    // therefore not relevant to the heuristic.
+    if (thisPid == windowOwnerPid) {
+      continue;
+    }
+
+    CFStringRef windowName = reinterpret_cast<CFStringRef>(
+        CFDictionaryGetValue(windowDict, kCGWindowName));
+    if (!windowName) {
+      continue;
+    }
+
+    CFNumberRef windowLayerRef = reinterpret_cast<CFNumberRef>(
+        CFDictionaryGetValue(windowDict, kCGWindowLayer));
+    int32_t windowLayer;
+    if (!windowLayerRef ||
+        !CFNumberGetValue(windowLayerRef, kCFNumberIntType, &windowLayer)) {
+      LOG("GetScreenCapturePermissionState() ERROR: failed to get layer");
+      continue;
+    }
+
+    // If we have a window name and the window is in the dock or normal window
+    // level, and for another process, assume we have screen recording access.
+    LOG("GetScreenCapturePermissionState(): windowLayer: %d", windowLayer);
+    if (windowLayer == windowLevelDock || windowLayer == windowLevelNormal) {
+      aPermissionState = nsIOSPermissionRequest::PERMISSION_STATE_AUTHORIZED;
+      LOG("screen authorization status: authorized");
+      return NS_OK;
+    }
+  }
+
+  aPermissionState = nsIOSPermissionRequest::PERMISSION_STATE_DENIED;
+  LOG("screen authorization status: not authorized");
+  return NS_OK;
+}
+
+nsresult nsCocoaUtils::RequestVideoCapturePermission(
+    RefPtr<Promise>& aPromise) {
+  MOZ_ASSERT(NS_IsMainThread());
+  return nsCocoaUtils::RequestCapturePermission(AVMediaTypeVideo, aPromise,
+                                                sVideoCapturePromises,
+                                                VideoCompletionHandler);
+}
+
+nsresult nsCocoaUtils::RequestAudioCapturePermission(
+    RefPtr<Promise>& aPromise) {
+  MOZ_ASSERT(NS_IsMainThread());
+  return nsCocoaUtils::RequestCapturePermission(AVMediaTypeAudio, aPromise,
+                                                sAudioCapturePromises,
+                                                AudioCompletionHandler);
+}
+
+//
+// Stores |aPromise| on |aPromiseList| and starts an asynchronous media
+// capture request for the given media type |aType|. If we are already
+// waiting for a capture request for this media type, don't start a new
+// request. |aHandler| is invoked on an arbitrary dispatch queue when the
+// request completes and must resolve any waiting Promises on the main
+// thread.
+//
+nsresult nsCocoaUtils::RequestCapturePermission(
+    AVMediaType aType, RefPtr<Promise>& aPromise, PromiseArray& aPromiseList,
+    void (^aHandler)(BOOL granted)) {
+  MOZ_ASSERT(aType == AVMediaTypeVideo || aType == AVMediaTypeAudio);
+  LOG("RequestCapturePermission(%s)", AVMediaTypeToString(aType));
+
+  sMediaCaptureMutex.Lock();
+
+  // Initialize our list of promises on first invocation
+  if (aPromiseList == nullptr) {
+    aPromiseList = new nsTArray<RefPtr<Promise>>;
+    ClearOnShutdown(&aPromiseList);
+  }
+
+  aPromiseList->AppendElement(aPromise);
+  size_t nPromises = aPromiseList->Length();
+
+  sMediaCaptureMutex.Unlock();
+
+  LOG("RequestCapturePermission(%s): %ld promise(s) unresolved",
+      AVMediaTypeToString(aType), nPromises);
+
+  // If we had one or more more existing promises waiting to be resolved
+  // by the completion handler, we don't need to start another request.
+  if (nPromises > 1) {
+    return NS_OK;
+  }
+
+  // Start the request
+  [AVCaptureDevice requestAccessForMediaType:aType completionHandler:aHandler];
+  return NS_OK;
+}
+
+//
+// Audio capture request completion handler. Called from an arbitrary
+// dispatch queue.
+//
+void (^nsCocoaUtils::AudioCompletionHandler)(BOOL) = ^void(BOOL granted) {
+  nsCocoaUtils::ResolveAudioCapturePromises(granted);
+};
+
+//
+// Video capture request completion handler. Called from an arbitrary
+// dispatch queue.
+//
+void (^nsCocoaUtils::VideoCompletionHandler)(BOOL) = ^void(BOOL granted) {
+  nsCocoaUtils::ResolveVideoCapturePromises(granted);
+};
+
+void nsCocoaUtils::ResolveMediaCapturePromises(bool aGranted,
+                                               PromiseArray& aPromiseList) {
+  StaticMutexAutoLock lock(sMediaCaptureMutex);
+
+  // Remove each promise from the list and resolve it.
+  while (aPromiseList->Length() > 0) {
+    RefPtr<Promise> promise = aPromiseList->PopLastElement();
+
+    // Resolve on main thread
+    nsCOMPtr<nsIRunnable> runnable(
+        NS_NewRunnableFunction("ResolveMediaAccessPromise",
+                               [aGranted, aPromise = std::move(promise)]() {
+                                 aPromise->MaybeResolve(aGranted);
+                               }));
+    NS_DispatchToMainThread(runnable.forget());
+  }
+}
+
+void nsCocoaUtils::ResolveAudioCapturePromises(bool aGranted) {
+  // Resolve on main thread
+  nsCOMPtr<nsIRunnable> runnable(
+      NS_NewRunnableFunction("ResolveAudioCapturePromise", [aGranted]() {
+        ResolveMediaCapturePromises(aGranted, sAudioCapturePromises);
+      }));
+  NS_DispatchToMainThread(runnable.forget());
+}
+
+//
+// Attempt to trigger a dialog requesting permission to record the screen.
+// Unlike with the camera and microphone, there is no API to request permission
+// to record the screen or to receive a callback when permission is explicitly
+// allowed or denied. Here we attempt to trigger the dialog by attempting to
+// capture a 1x1 pixel section of the screen. The permission dialog is not
+// guaranteed to be displayed because the user may have already been prompted
+// in which case macOS does not display the dialog again.
+//
+nsresult nsCocoaUtils::MaybeRequestScreenCapturePermission() {
+  LOG("MaybeRequestScreenCapturePermission()");
+  AutoCFRelease<CGImageRef> image =
+      CGDisplayCreateImageForRect(kCGDirectMainDisplay, CGRectMake(0, 0, 1, 1));
+  return NS_OK;
+}
+
+void nsCocoaUtils::ResolveVideoCapturePromises(bool aGranted) {
+  // Resolve on main thread
+  nsCOMPtr<nsIRunnable> runnable(
+      NS_NewRunnableFunction("ResolveVideoCapturePromise", [aGranted]() {
+        ResolveMediaCapturePromises(aGranted, sVideoCapturePromises);
+      }));
+  NS_DispatchToMainThread(runnable.forget());
+}
+
+static PanGestureInput::PanGestureType PanGestureTypeForEvent(NSEvent* aEvent) {
+  switch ([aEvent phase]) {
+    case NSEventPhaseMayBegin:
+      return PanGestureInput::PANGESTURE_MAYSTART;
+    case NSEventPhaseCancelled:
+      return PanGestureInput::PANGESTURE_CANCELLED;
+    case NSEventPhaseBegan:
+      return PanGestureInput::PANGESTURE_START;
+    case NSEventPhaseChanged:
+      return PanGestureInput::PANGESTURE_PAN;
+    case NSEventPhaseEnded:
+      return PanGestureInput::PANGESTURE_END;
+    case NSEventPhaseNone:
+      switch ([aEvent momentumPhase]) {
+        case NSEventPhaseBegan:
+          return PanGestureInput::PANGESTURE_MOMENTUMSTART;
+        case NSEventPhaseChanged:
+          return PanGestureInput::PANGESTURE_MOMENTUMPAN;
+        case NSEventPhaseEnded:
+          return PanGestureInput::PANGESTURE_MOMENTUMEND;
+        default:
+          NS_ERROR("unexpected event phase");
+          return PanGestureInput::PANGESTURE_PAN;
+      }
+    default:
+      NS_ERROR("unexpected event phase");
+      return PanGestureInput::PANGESTURE_PAN;
+  }
+}
+
+bool static ShouldConsiderStartingSwipeFromEvent(NSEvent* anEvent) {
+  // Only initiate horizontal tracking for gestures that have just begun --
+  // otherwise a scroll to one side of the page can have a swipe tacked on
+  // to it.
+  // [NSEvent isSwipeTrackingFromScrollEventsEnabled] checks whether the
+  // AppleEnableSwipeNavigateWithScrolls global preference is set.  If it isn't,
+  // fluid swipe tracking is disabled, and a horizontal two-finger gesture is
+  // always a scroll (even in Safari).  This preference can't (currently) be set
+  // from the Preferences UI -- only using 'defaults write'.
+  NSEventPhase eventPhase = [anEvent phase];
+  return [anEvent type] == NSEventTypeScrollWheel &&
+         eventPhase == NSEventPhaseBegan &&
+         [anEvent hasPreciseScrollingDeltas] &&
+         [NSEvent isSwipeTrackingFromScrollEventsEnabled];
+}
+
+PanGestureInput nsCocoaUtils::CreatePanGestureEvent(
+    NSEvent* aNativeEvent, TimeStamp aTimeStamp,
+    const ScreenPoint& aPanStartPoint, const ScreenPoint& aPreciseDelta,
+    const gfx::IntPoint& aLineOrPageDelta, Modifiers aModifiers) {
+  PanGestureInput::PanGestureType type = PanGestureTypeForEvent(aNativeEvent);
+  // Always force zero deltas on event types that shouldn't cause any scrolling,
+  // so that we don't dispatch DOM wheel events for them.
+  bool shouldIgnoreDeltas = type == PanGestureInput::PANGESTURE_MAYSTART ||
+                            type == PanGestureInput::PANGESTURE_CANCELLED;
+
+  PanGestureInput panEvent(
+      type, aTimeStamp, aPanStartPoint,
+      !shouldIgnoreDeltas ? aPreciseDelta : ScreenPoint(), aModifiers,
+      PanGestureInput::IsEligibleForSwipe(
+          ShouldConsiderStartingSwipeFromEvent(aNativeEvent)));
+
+  if (!shouldIgnoreDeltas) {
+    panEvent.SetLineOrPageDeltas(aLineOrPageDelta.x, aLineOrPageDelta.y);
+  }
+
+  return panEvent;
+}
+
+bool nsCocoaUtils::IsValidPasteboardType(NSString* aAvailableType,
+                                         bool aAllowFileURL) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // Prevent exposing fileURL for non-fileURL type.
+  // We need URL provided by dropped webloc file, but don't need file's URL.
+  // kUTTypeFileURL is returned by [NSPasteboard availableTypeFromArray:] for
+  // kPublicUrlPboardType, since it conforms to kPublicUrlPboardType.
+  bool isValid = true;
+  if (!aAllowFileURL &&
+      [aAvailableType
+          isEqualToString:[UTIHelper
+                              stringFromPboardType:(NSString*)
+                                                       kUTTypeFileURL]]) {
+    isValid = false;
+  }
+
+  return isValid;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
+
+NSString* nsCocoaUtils::GetStringForTypeFromPasteboardItem(
+    NSPasteboardItem* aItem, const NSString* aType, bool aAllowFileURL) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSString* availableType =
+      [aItem availableTypeFromArray:[NSArray arrayWithObjects:(id)aType, nil]];
+  if (availableType && IsValidPasteboardType(availableType, aAllowFileURL)) {
+    return [aItem stringForType:(id)availableType];
+  }
+
+  return nil;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+NSString* nsCocoaUtils::GetFilePathFromPasteboardItem(NSPasteboardItem* aItem) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSString* urlString = GetStringForTypeFromPasteboardItem(
+      aItem, [UTIHelper stringFromPboardType:(NSString*)kUTTypeFileURL], true);
+  if (urlString) {
+    NSURL* url = [NSURL URLWithString:urlString];
+    if (url) {
+      return [url path];
+    }
+  }
+
+  return nil;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+NSString* nsCocoaUtils::GetTitleForURLFromPasteboardItem(
+    NSPasteboardItem* item) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSString* name = nsCocoaUtils::GetStringForTypeFromPasteboardItem(
+      item, [UTIHelper stringFromPboardType:kPublicUrlNamePboardType]);
+  if (name) {
+    return name;
+  }
+
+  NSString* filePath = nsCocoaUtils::GetFilePathFromPasteboardItem(item);
+  if (filePath) {
+    return [filePath lastPathComponent];
+  }
+
+  return nil;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+void nsCocoaUtils::SetTransferDataForTypeFromPasteboardItem(
+    nsITransferable* aTransferable, const nsCString& aFlavor,
+    NSPasteboardItem* aItem) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!aTransferable || !aItem) {
+    return;
+  }
+
+  MOZ_LOG(gCocoaUtilsLog, LogLevel::Info,
+          ("nsCocoaUtils::SetTransferDataForTypeFromPasteboardItem: looking "
+           "for pasteboard data of "
+           "type %s\n",
+           aFlavor.get()));
+
+  if (aFlavor.EqualsLiteral(kFileMime)) {
+    NSString* filePath = nsCocoaUtils::GetFilePathFromPasteboardItem(aItem);
+    if (!filePath) {
+      return;
+    }
+
+    unsigned int stringLength = [filePath length];
+    unsigned int dataLength =
+        (stringLength + 1) * sizeof(char16_t);  // in bytes
+    char16_t* clipboardDataPtr = (char16_t*)malloc(dataLength);
+    if (!clipboardDataPtr) {
+      return;
+    }
+
+    [filePath getCharacters:reinterpret_cast<unichar*>(clipboardDataPtr)];
+    clipboardDataPtr[stringLength] = 0;  // null terminate
+
+    nsCOMPtr<nsIFile> file;
+    nsresult rv = NS_NewLocalFile(nsDependentString(clipboardDataPtr), true,
+                                  getter_AddRefs(file));
+    free(clipboardDataPtr);
+    if (NS_FAILED(rv)) {
+      return;
+    }
+
+    aTransferable->SetTransferData(aFlavor.get(), file);
+    return;
+  }
+
+  if (aFlavor.EqualsLiteral(kCustomTypesMime)) {
+    NSString* availableType = [aItem
+        availableTypeFromArray:[NSArray
+                                   arrayWithObject:kMozCustomTypesPboardType]];
+    if (!availableType ||
+        !nsCocoaUtils::IsValidPasteboardType(availableType, false)) {
+      return;
+    }
+    NSData* pasteboardData = [aItem dataForType:availableType];
+    if (!pasteboardData) {
+      return;
+    }
+
+    unsigned int dataLength = [pasteboardData length];
+    void* clipboardDataPtr = malloc(dataLength);
+    if (!clipboardDataPtr) {
+      return;
+    }
+    [pasteboardData getBytes:clipboardDataPtr length:dataLength];
+
+    nsCOMPtr<nsISupports> genericDataWrapper;
+    nsPrimitiveHelpers::CreatePrimitiveForData(
+        aFlavor, clipboardDataPtr, dataLength,
+        getter_AddRefs(genericDataWrapper));
+
+    aTransferable->SetTransferData(aFlavor.get(), genericDataWrapper);
+    free(clipboardDataPtr);
+    return;
+  }
+
+  NSString* pString = nil;
+  if (aFlavor.EqualsLiteral(kTextMime)) {
+    pString = nsCocoaUtils::GetStringForTypeFromPasteboardItem(
+        aItem, [UTIHelper stringFromPboardType:NSPasteboardTypeString]);
+  } else if (aFlavor.EqualsLiteral(kHTMLMime)) {
+    pString = nsCocoaUtils::GetStringForTypeFromPasteboardItem(
+        aItem, [UTIHelper stringFromPboardType:NSPasteboardTypeHTML]);
+  } else if (aFlavor.EqualsLiteral(kURLMime)) {
+    pString = nsCocoaUtils::GetStringForTypeFromPasteboardItem(
+        aItem, [UTIHelper stringFromPboardType:kPublicUrlPboardType]);
+    if (pString) {
+      NSString* title = GetTitleForURLFromPasteboardItem(aItem);
+      if (!title) {
+        title = pString;
+      }
+      pString = [NSString stringWithFormat:@"%@\n%@", pString, title];
+    }
+  } else if (aFlavor.EqualsLiteral(kURLDataMime)) {
+    pString = nsCocoaUtils::GetStringForTypeFromPasteboardItem(
+        aItem, [UTIHelper stringFromPboardType:kPublicUrlPboardType]);
+  } else if (aFlavor.EqualsLiteral(kURLDescriptionMime)) {
+    pString = GetTitleForURLFromPasteboardItem(aItem);
+  } else if (aFlavor.EqualsLiteral(kRTFMime)) {
+    pString = nsCocoaUtils::GetStringForTypeFromPasteboardItem(
+        aItem, [UTIHelper stringFromPboardType:NSPasteboardTypeRTF]);
+  }
+  if (pString) {
+    NSData* stringData;
+    bool isRTF = aFlavor.EqualsLiteral(kRTFMime);
+    if (isRTF) {
+      stringData = [pString dataUsingEncoding:NSASCIIStringEncoding];
+    } else {
+      stringData = [pString dataUsingEncoding:NSUnicodeStringEncoding];
+    }
+    unsigned int dataLength = [stringData length];
+    void* clipboardDataPtr = malloc(dataLength);
+    if (!clipboardDataPtr) {
+      return;
+    }
+    [stringData getBytes:clipboardDataPtr length:dataLength];
+
+    // The DOM only wants LF, so convert from MacOS line endings to DOM line
+    // endings.
+    int32_t signedDataLength = dataLength;
+    nsLinebreakHelpers::ConvertPlatformToDOMLinebreaks(isRTF, &clipboardDataPtr,
+                                                       &signedDataLength);
+    dataLength = signedDataLength;
+
+    // skip BOM (Byte Order Mark to distinguish little or big endian)
+    char16_t* clipboardDataPtrNoBOM = (char16_t*)clipboardDataPtr;
+    if ((dataLength > 2) && ((clipboardDataPtrNoBOM[0] == 0xFEFF) ||
+                             (clipboardDataPtrNoBOM[0] == 0xFFFE))) {
+      dataLength -= sizeof(char16_t);
+      clipboardDataPtrNoBOM += 1;
+    }
+
+    nsCOMPtr<nsISupports> genericDataWrapper;
+    nsPrimitiveHelpers::CreatePrimitiveForData(
+        aFlavor, clipboardDataPtrNoBOM, dataLength,
+        getter_AddRefs(genericDataWrapper));
+    aTransferable->SetTransferData(aFlavor.get(), genericDataWrapper);
+    free(clipboardDataPtr);
+    return;
+  }
+
+  // We have never supported this on Mac OS X, we should someday. Normally
+  // dragging images in is accomplished with a file path drag instead of the
+  // image data itself.
+  /*
+  if (aFlavor.EqualsLiteral(kPNGImageMime) ||
+  aFlavor.EqualsLiteral(kJPEGImageMime) || aFlavor.EqualsLiteral(kJPGImageMime)
+  || aFlavor.EqualsLiteral(kGIFImageMime)) {
+
+  }
+  */
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
diff --git a/widget/cocoa/nsCocoaWindow.h b/widget/cocoa/nsCocoaWindow.h
new file mode 100644
index 0000000000..c2e595677f
--- /dev/null
+++ b/widget/cocoa/nsCocoaWindow.h
@@ -0,0 +1,515 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsCocoaWindow_h_
+#define nsCocoaWindow_h_
+
+#undef DARWIN
+
+#import <Cocoa/Cocoa.h>
+
+#include "mozilla/RefPtr.h"
+#include "nsBaseWidget.h"
+#include "nsPIWidgetCocoa.h"
+#include "nsCocoaUtils.h"
+#include "nsTouchBar.h"
+#include <dlfcn.h>
+#include <queue>
+
+class nsCocoaWindow;
+class nsChildView;
+class nsMenuBarX;
+@class ChildView;
+
+namespace mozilla {
+enum class NativeKeyBindingsType : uint8_t;
+}  // namespace mozilla
+
+typedef struct _nsCocoaWindowList {
+  _nsCocoaWindowList() : prev(nullptr), window(nullptr) {}
+  struct _nsCocoaWindowList* prev;
+  nsCocoaWindow* window;  // Weak
+} nsCocoaWindowList;
+
+// NSWindow subclass that is the base class for all of our own window classes.
+// Among other things, this class handles the storage of those settings that
+// need to be persisted across window destruction and reconstruction, i.e. when
+// switching to and from fullscreen mode.
+// We don't save shadow, transparency mode or background color because it's not
+// worth the hassle - Gecko will reset them anyway as soon as the window is
+// resized.
+@interface BaseWindow : NSWindow {
+  // Data Storage
+  NSMutableDictionary* mState;
+  BOOL mDrawsIntoWindowFrame;
+
+  // Invalidation disabling
+  BOOL mDisabledNeedsDisplay;
+
+  NSTrackingArea* mTrackingArea;
+
+  NSRect mDirtyRect;
+
+  BOOL mBeingShown;
+  BOOL mDrawTitle;
+  BOOL mIsAnimationSuppressed;
+
+  nsTouchBar* mTouchBar;
+}
+
+- (void)importState:(NSDictionary*)aState;
+- (NSMutableDictionary*)exportState;
+- (void)setDrawsContentsIntoWindowFrame:(BOOL)aState;
+- (BOOL)drawsContentsIntoWindowFrame;
+
+// These two methods are like contentRectForFrameRect and
+// frameRectForContentRect, but they deal with the rect of the window's "main
+// ChildView" instead of the rect of the window's content view. The two are
+// sometimes sized differently: The window's content view always covers the
+// entire window, whereas the ChildView only covers the full window when
+// drawsContentsIntoWindowFrame is YES. When drawsContentsIntoWindowFrame is NO,
+// there's a titlebar-sized gap above the ChildView within the content view.
+- (NSRect)childViewRectForFrameRect:(NSRect)aFrameRect;
+- (NSRect)frameRectForChildViewRect:(NSRect)aChildViewRect;
+
+- (void)mouseEntered:(NSEvent*)aEvent;
+- (void)mouseExited:(NSEvent*)aEvent;
+- (void)mouseMoved:(NSEvent*)aEvent;
+- (void)updateTrackingArea;
+- (NSView*)trackingAreaView;
+
+- (void)setBeingShown:(BOOL)aValue;
+- (BOOL)isBeingShown;
+- (BOOL)isVisibleOrBeingShown;
+
+- (void)setIsAnimationSuppressed:(BOOL)aValue;
+- (BOOL)isAnimationSuppressed;
+
+// Returns an autoreleased NSArray containing the NSViews that we consider the
+// "contents" of this window. All views in the returned array are subviews of
+// this window's content view. However, the array may not include all of the
+// content view's subviews; concretely, the ToolbarWindow implementation will
+// exclude its MOZTitlebarView from the array that is returned here.
+// In the vast majority of cases, the array will only have a single element:
+// this window's mainChildView.
+- (NSArray<NSView*>*)contentViewContents;
+
+- (ChildView*)mainChildView;
+
+- (void)setWantsTitleDrawn:(BOOL)aDrawTitle;
+- (BOOL)wantsTitleDrawn;
+
+- (void)disableSetNeedsDisplay;
+- (void)enableSetNeedsDisplay;
+
+- (NSRect)getAndResetNativeDirtyRect;
+
+- (void)setEffectViewWrapperForStyle:(mozilla::WindowShadow)aStyle;
+@property(nonatomic) mozilla::WindowShadow shadowStyle;
+
+- (void)releaseJSObjects;
+
+@end
+
+@interface NSWindow (Undocumented)
+- (NSDictionary*)shadowParameters;
+
+// Present in the same form on OS X since at least OS X 10.5.
+- (NSRect)contentRectForFrameRect:(NSRect)windowFrame
+                        styleMask:(NSUInteger)windowStyle;
+- (NSRect)frameRectForContentRect:(NSRect)windowContentRect
+                        styleMask:(NSUInteger)windowStyle;
+
+// Present since at least OS X 10.5.  The OS calls this method on NSWindow
+// (and its subclasses) to find out which NSFrameView subclass to instantiate
+// to create its "frame view".
++ (Class)frameViewClassForStyleMask:(NSUInteger)styleMask;
+
+@end
+
+@interface PopupWindow : BaseWindow {
+ @private
+  BOOL mIsContextMenu;
+}
+
+- (id)initWithContentRect:(NSRect)contentRect
+                styleMask:(NSUInteger)styleMask
+                  backing:(NSBackingStoreType)bufferingType
+                    defer:(BOOL)deferCreation;
+- (BOOL)isContextMenu;
+- (void)setIsContextMenu:(BOOL)flag;
+- (BOOL)canBecomeMainWindow;
+
+@end
+
+@interface BorderlessWindow : BaseWindow {
+}
+
+- (BOOL)canBecomeKeyWindow;
+- (BOOL)canBecomeMainWindow;
+
+@end
+
+@interface WindowDelegate : NSObject <NSWindowDelegate> {
+  nsCocoaWindow* mGeckoWindow;  // [WEAK] (we are owned by the window)
+  // Used to avoid duplication when we send NS_ACTIVATE and
+  // NS_DEACTIVATE to Gecko for toplevel widgets.  Starts out
+  // false.
+  bool mToplevelActiveState;
+  BOOL mHasEverBeenZoomed;
+}
++ (void)paintMenubarForWindow:(NSWindow*)aWindow;
+- (id)initWithGeckoWindow:(nsCocoaWindow*)geckoWind;
+- (void)windowDidResize:(NSNotification*)aNotification;
+- (nsCocoaWindow*)geckoWidget;
+- (bool)toplevelActiveState;
+- (void)sendToplevelActivateEvents;
+- (void)sendToplevelDeactivateEvents;
+@end
+
+@interface MOZTitlebarView : NSVisualEffectView
+@end
+
+@interface FullscreenTitlebarTracker : NSTitlebarAccessoryViewController
+- (FullscreenTitlebarTracker*)init;
+@end
+
+// NSWindow subclass for handling windows with toolbars.
+@interface ToolbarWindow : BaseWindow {
+  // This window's titlebar view, if present.
+  // Will be nil if the window has neither a titlebar nor a unified toolbar.
+  // This view is a subview of the window's content view and gets created and
+  // destroyed by updateTitlebarView.
+  MOZTitlebarView* mTitlebarView;  // [STRONG]
+  // mFullscreenTitlebarTracker attaches an invisible rectangle to the system
+  // title bar. This allows us to detect when the title bar is showing in
+  // fullscreen.
+  FullscreenTitlebarTracker* mFullscreenTitlebarTracker;
+
+  CGFloat mUnifiedToolbarHeight;
+  CGFloat mSheetAttachmentPosition;
+  CGFloat mMenuBarHeight;
+  /* Store the height of the titlebar when this window is initialized. The
+     titlebarHeight getter returns 0 when in fullscreen, which is not useful in
+     some cases. */
+  CGFloat mInitialTitlebarHeight;
+  NSRect mWindowButtonsRect;
+}
+- (void)setUnifiedToolbarHeight:(CGFloat)aHeight;
+- (CGFloat)unifiedToolbarHeight;
+- (CGFloat)titlebarHeight;
+- (NSRect)titlebarRect;
+- (void)setTitlebarNeedsDisplay;
+- (void)setDrawsContentsIntoWindowFrame:(BOOL)aState;
+- (void)setSheetAttachmentPosition:(CGFloat)aY;
+- (CGFloat)sheetAttachmentPosition;
+- (void)placeWindowButtons:(NSRect)aRect;
+- (NSRect)windowButtonsRect;
+- (void)windowMainStateChanged;
+@end
+
+class nsCocoaWindow final : public nsBaseWidget, public nsPIWidgetCocoa {
+ private:
+  typedef nsBaseWidget Inherited;
+
+ public:
+  nsCocoaWindow();
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSPIWIDGETCOCOA;  // semicolon for clang-format bug 1629756
+
+  [[nodiscard]] virtual nsresult Create(nsIWidget* aParent,
+                                        nsNativeWidget aNativeParent,
+                                        const DesktopIntRect& aRect,
+                                        InitData* = nullptr) override;
+
+  [[nodiscard]] virtual nsresult Create(nsIWidget* aParent,
+                                        nsNativeWidget aNativeParent,
+                                        const LayoutDeviceIntRect& aRect,
+                                        InitData* = nullptr) override;
+
+  virtual void Destroy() override;
+
+  virtual void Show(bool aState) override;
+  virtual bool NeedsRecreateToReshow() override;
+
+  virtual nsIWidget* GetSheetWindowParent(void) override;
+  virtual void Enable(bool aState) override;
+  virtual bool IsEnabled() const override;
+  virtual void SetModal(bool aState) override;
+  virtual void SetFakeModal(bool aState) override;
+  virtual bool IsRunningAppModal() override;
+  virtual bool IsVisible() const override;
+  virtual void SetFocus(Raise, mozilla::dom::CallerType aCallerType) override;
+  virtual LayoutDeviceIntPoint WidgetToScreenOffset() override;
+  virtual LayoutDeviceIntPoint GetClientOffset() override;
+  virtual LayoutDeviceIntMargin ClientToWindowMargin() override;
+
+  virtual void* GetNativeData(uint32_t aDataType) override;
+
+  virtual void ConstrainPosition(DesktopIntPoint&) override;
+  virtual void SetSizeConstraints(const SizeConstraints& aConstraints) override;
+  virtual void Move(double aX, double aY) override;
+  virtual nsSizeMode SizeMode() override { return mSizeMode; }
+  virtual void SetSizeMode(nsSizeMode aMode) override;
+  virtual void GetWorkspaceID(nsAString& workspaceID) override;
+  virtual void MoveToWorkspace(const nsAString& workspaceID) override;
+  virtual void SuppressAnimation(bool aSuppress) override;
+  virtual void HideWindowChrome(bool aShouldHide) override;
+
+  virtual bool PrepareForFullscreenTransition(nsISupports** aData) override;
+  virtual void PerformFullscreenTransition(FullscreenTransitionStage aStage,
+                                           uint16_t aDuration,
+                                           nsISupports* aData,
+                                           nsIRunnable* aCallback) override;
+  virtual void CleanupFullscreenTransition() override;
+  nsresult MakeFullScreen(bool aFullScreen) final;
+  nsresult MakeFullScreenWithNativeTransition(bool aFullScreen) final;
+  NSAnimation* FullscreenTransitionAnimation() const {
+    return mFullscreenTransitionAnimation;
+  }
+  void ReleaseFullscreenTransitionAnimation() {
+    MOZ_ASSERT(mFullscreenTransitionAnimation,
+               "Should only be called when there is animation");
+    [mFullscreenTransitionAnimation release];
+    mFullscreenTransitionAnimation = nil;
+  }
+
+  virtual void Resize(double aWidth, double aHeight, bool aRepaint) override;
+  virtual void Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) override;
+  NSRect GetClientCocoaRect();
+  virtual LayoutDeviceIntRect GetClientBounds() override;
+  virtual LayoutDeviceIntRect GetScreenBounds() override;
+  void ReportMoveEvent();
+  void ReportSizeEvent();
+  virtual void SetCursor(const Cursor&) override;
+
+  CGFloat BackingScaleFactor();
+  void BackingScaleFactorChanged();
+  virtual double GetDefaultScaleInternal() override;
+  virtual int32_t RoundsWidgetCoordinatesTo() override;
+
+  mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale() final {
+    return mozilla::DesktopToLayoutDeviceScale(BackingScaleFactor());
+  }
+
+  virtual nsresult SetTitle(const nsAString& aTitle) override;
+
+  virtual void Invalidate(const LayoutDeviceIntRect& aRect) override;
+  virtual WindowRenderer* GetWindowRenderer() override;
+  virtual nsresult DispatchEvent(mozilla::WidgetGUIEvent* aEvent,
+                                 nsEventStatus& aStatus) override;
+  virtual void CaptureRollupEvents(bool aDoCapture) override;
+  [[nodiscard]] virtual nsresult GetAttention(int32_t aCycleCount) override;
+  virtual bool HasPendingInputEvent() override;
+  virtual TransparencyMode GetTransparencyMode() override;
+  virtual void SetTransparencyMode(TransparencyMode aMode) override;
+  virtual void SetWindowShadowStyle(mozilla::WindowShadow aStyle) override;
+  virtual void SetWindowOpacity(float aOpacity) override;
+  virtual void SetWindowTransform(
+      const mozilla::gfx::Matrix& aTransform) override;
+  virtual void SetInputRegion(const InputRegion&) override;
+  virtual void SetColorScheme(
+      const mozilla::Maybe<mozilla::ColorScheme>&) override;
+  virtual void SetShowsToolbarButton(bool aShow) override;
+  virtual void SetSupportsNativeFullscreen(bool aShow) override;
+  virtual void SetWindowAnimationType(WindowAnimationType aType) override;
+  virtual void SetDrawsTitle(bool aDrawTitle) override;
+  virtual nsresult SetNonClientMargins(const LayoutDeviceIntMargin&) override;
+  void SetDrawsInTitlebar(bool aState);
+  virtual void UpdateThemeGeometries(
+      const nsTArray<ThemeGeometry>& aThemeGeometries) override;
+  virtual nsresult SynthesizeNativeMouseEvent(
+      LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+      mozilla::MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+      nsIObserver* aObserver) override;
+  virtual nsresult SynthesizeNativeMouseScrollEvent(
+      LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage, double aDeltaX,
+      double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+      uint32_t aAdditionalFlags, nsIObserver* aObserver) override;
+  virtual void LockAspectRatio(bool aShouldLock) override;
+
+  void DispatchSizeModeEvent();
+  void DispatchOcclusionEvent();
+
+  // be notified that a some form of drag event needs to go into Gecko
+  virtual bool DragEvent(unsigned int aMessage,
+                         mozilla::gfx::Point aMouseGlobal,
+                         UInt16 aKeyModifiers);
+
+  bool HasModalDescendents() { return mNumModalDescendents > 0; }
+  NSWindow* GetCocoaWindow() { return mWindow; }
+
+  void SetMenuBar(RefPtr<nsMenuBarX>&& aMenuBar);
+  nsMenuBarX* GetMenuBar();
+
+  virtual void SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction) override;
+  virtual InputContext GetInputContext() override { return mInputContext; }
+  MOZ_CAN_RUN_SCRIPT virtual bool GetEditCommands(
+      mozilla::NativeKeyBindingsType aType,
+      const mozilla::WidgetKeyboardEvent& aEvent,
+      nsTArray<mozilla::CommandInt>& aCommands) override;
+
+  void SetPopupWindowLevel();
+
+  bool InFullScreenMode() const { return mInFullScreenMode; }
+
+  void PauseOrResumeCompositor(bool aPause) override;
+
+  bool AsyncPanZoomEnabled() const override;
+
+  bool StartAsyncAutoscroll(const ScreenPoint& aAnchorLocation,
+                            const ScrollableLayerGuid& aGuid) override;
+  void StopAsyncAutoscroll(const ScrollableLayerGuid& aGuid) override;
+
+  // Class method versions of NSWindow/Delegate callbacks which need to
+  // access object state.
+  void CocoaWindowWillEnterFullscreen(bool aFullscreen);
+  void CocoaWindowDidEnterFullscreen(bool aFullscreen);
+  void CocoaWindowDidResize();
+  void CocoaSendToplevelActivateEvents();
+  void CocoaSendToplevelDeactivateEvents();
+
+  enum class TransitionType {
+    Windowed,
+    Fullscreen,
+    EmulatedFullscreen,
+    Miniaturize,
+    Deminiaturize,
+    Zoom,
+  };
+  void FinishCurrentTransitionIfMatching(const TransitionType& aTransition);
+
+  // Called when something has happened that might cause us to update our
+  // fullscreen state. Returns true if we updated state. We'll call this
+  // on window resize, and we'll call it when we enter or exit fullscreen,
+  // since fullscreen to-and-from zoomed windows won't necessarily trigger
+  // a resize.
+  bool HandleUpdateFullscreenOnResize();
+
+ protected:
+  virtual ~nsCocoaWindow();
+
+  nsresult CreateNativeWindow(const NSRect& aRect, BorderStyle aBorderStyle,
+                              bool aRectIsFrameRect, bool aIsPrivateBrowsing);
+  nsresult CreatePopupContentView(const LayoutDeviceIntRect& aRect, InitData*);
+  void DestroyNativeWindow();
+  void UpdateBounds();
+  int32_t GetWorkspaceID();
+
+  void DoResize(double aX, double aY, double aWidth, double aHeight,
+                bool aRepaint, bool aConstrainToCurrentScreen);
+
+  void UpdateFullscreenState(bool aFullScreen, bool aNativeMode);
+  nsresult DoMakeFullScreen(bool aFullScreen, bool aUseSystemTransition);
+
+  virtual already_AddRefed<nsIWidget> AllocateChildPopupWidget() override {
+    return nsIWidget::CreateTopLevelWindow();
+  }
+
+  nsIWidget* mParent;        // if we're a popup, this is our parent [WEAK]
+  nsIWidget* mAncestorLink;  // link to traverse ancestors [WEAK]
+  BaseWindow* mWindow;       // our cocoa window [STRONG]
+  WindowDelegate*
+      mDelegate;  // our delegate for processing window msgs [STRONG]
+  RefPtr<nsMenuBarX> mMenuBar;
+  NSWindow* mSheetWindowParent;  // if this is a sheet, this is the NSWindow
+                                 // it's attached to
+  nsChildView*
+      mPopupContentView;  // if this is a popup, this is its content widget
+  // if this is a toplevel window, and there is any ongoing fullscreen
+  // transition, it is the animation object.
+  NSAnimation* mFullscreenTransitionAnimation;
+  mozilla::WindowShadow mShadowStyle;
+
+  CGFloat mBackingScaleFactor;
+  CGFloat mAspectRatio;
+
+  WindowAnimationType mAnimationType;
+
+  bool mWindowMadeHere;  // true if we created the window, false for embedding
+  bool mSheetNeedsShow;  // if this is a sheet, are we waiting to be shown?
+                         // this is used for sibling sheet contention only
+  nsSizeMode mSizeMode;
+  bool mInFullScreenMode;
+  // Whether we are currently using native fullscreen. It could be false because
+  // we are in the emulated fullscreen where we do not use the native
+  // fullscreen.
+  bool mInNativeFullScreenMode;
+
+  mozilla::Maybe<TransitionType> mTransitionCurrent;
+  std::queue<TransitionType> mTransitionsPending;
+
+  // Sometimes we add a transition that wasn't requested by a caller. We do this
+  // to manage transitions between states that otherwise would be rejected by
+  // Cocoa. When we do this, it's useful to know when we are handling an added
+  // transition because we don't want to send size mode events when they
+  // execute.
+  bool mIsTransitionCurrentAdded = false;
+
+  // Whether we are treating the next resize as the start of a fullscreen
+  // transition. If we are, which direction are we going: Fullscreen or
+  // Windowed.
+  mozilla::Maybe<TransitionType> mUpdateFullscreenOnResize;
+
+  bool IsInTransition() { return mTransitionCurrent.isSome(); }
+  void QueueTransition(const TransitionType& aTransition);
+  void ProcessTransitions();
+
+  // Call this to stop all transition processing, which is useful during
+  // window closing and shutdown.
+  void CancelAllTransitions();
+
+  bool mInProcessTransitions = false;
+
+  // While running an emulated fullscreen transition, we want to suppress
+  // sending size mode events due to window resizing. We fix it up at the end
+  // when the transition is complete.
+  bool mSuppressSizeModeEvents = false;
+
+  // Ignore occlusion events caused by displaying the temporary fullscreen
+  // window during the fullscreen transition animation because only focused
+  // contexts are permitted to enter DOM fullscreen.
+  int mIgnoreOcclusionCount;
+
+  // Set to true when a native fullscreen transition is initiated -- either to
+  // or from fullscreen -- and set to false when it is complete. During this
+  // period, we presume the window is visible, which prevents us from sending
+  // unnecessary OcclusionStateChanged events.
+  bool mHasStartedNativeFullscreen;
+
+  bool mModal;
+  bool mFakeModal;
+
+  bool mIsAnimationSuppressed;
+
+  bool mInReportMoveEvent;  // true if in a call to ReportMoveEvent().
+  bool mInResize;           // true if in a call to DoResize().
+  bool mWindowTransformIsIdentity;
+  bool mAlwaysOnTop;
+  bool mAspectRatioLocked;
+
+  int32_t mNumModalDescendents;
+  InputContext mInputContext;
+  NSWindowAnimationBehavior mWindowAnimationBehavior;
+
+ private:
+  // This is class state for tracking which nsCocoaWindow, if any, is in the
+  // middle of a native fullscreen transition.
+  static nsCocoaWindow* sWindowInNativeTransition;
+
+  // This function returns true if the caller has been able to claim the sole
+  // permission to start a native transition. It must be followed by a call
+  // to EndOurNativeTransition() when the native transition is complete.
+  bool CanStartNativeTransition();
+  void EndOurNativeTransition();
+
+  // true if Show() has been called.
+  bool mWasShown;
+};
+
+#endif  // nsCocoaWindow_h_
diff --git a/widget/cocoa/nsCocoaWindow.mm b/widget/cocoa/nsCocoaWindow.mm
new file mode 100644
index 0000000000..e5abaa5a87
--- /dev/null
+++ b/widget/cocoa/nsCocoaWindow.mm
@@ -0,0 +1,4460 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsCocoaWindow.h"
+
+#include "AppearanceOverride.h"
+#include "NativeKeyBindings.h"
+#include "ScreenHelperCocoa.h"
+#include "TextInputHandler.h"
+#include "nsCocoaUtils.h"
+#include "nsObjCExceptions.h"
+#include "nsCOMPtr.h"
+#include "nsWidgetsCID.h"
+#include "nsIRollupListener.h"
+#include "nsChildView.h"
+#include "nsWindowMap.h"
+#include "nsAppShell.h"
+#include "nsIAppShellService.h"
+#include "nsIBaseWindow.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsIAppWindow.h"
+#include "nsToolkit.h"
+#include "nsPIDOMWindow.h"
+#include "nsThreadUtils.h"
+#include "nsMenuBarX.h"
+#include "nsMenuUtilsX.h"
+#include "nsStyleConsts.h"
+#include "nsNativeThemeColors.h"
+#include "nsNativeThemeCocoa.h"
+#include "nsChildView.h"
+#include "nsCocoaFeatures.h"
+#include "nsIScreenManager.h"
+#include "nsIWidgetListener.h"
+#include "nsXULPopupManager.h"
+#include "VibrancyManager.h"
+#include "nsPresContext.h"
+#include "nsDocShell.h"
+
+#include "gfxPlatform.h"
+#include "qcms.h"
+
+#include "mozilla/AutoRestore.h"
+#include "mozilla/BasicEvents.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPrefs_gfx.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/WritingModes.h"
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "mozilla/widget/Screen.h"
+#include <algorithm>
+
+namespace mozilla {
+namespace layers {
+class LayerManager;
+}  // namespace layers
+}  // namespace mozilla
+using namespace mozilla::layers;
+using namespace mozilla::widget;
+using namespace mozilla;
+
+int32_t gXULModalLevel = 0;
+
+// In principle there should be only one app-modal window at any given time.
+// But sometimes, despite our best efforts, another window appears above the
+// current app-modal window.  So we need to keep a linked list of app-modal
+// windows.  (A non-sheet window that appears above an app-modal window is
+// also made app-modal.)  See nsCocoaWindow::SetModal().
+nsCocoaWindowList* gGeckoAppModalWindowList = NULL;
+
+BOOL sTouchBarIsInitialized = NO;
+
+// defined in nsMenuBarX.mm
+extern NSMenu* sApplicationMenu;  // Application menu shared by all menubars
+
+// defined in nsChildView.mm
+extern BOOL gSomeMenuBarPainted;
+
+extern "C" {
+// CGSPrivate.h
+typedef NSInteger CGSConnection;
+typedef NSUInteger CGSSpaceID;
+typedef NSInteger CGSWindow;
+typedef enum {
+  kCGSSpaceIncludesCurrent = 1 << 0,
+  kCGSSpaceIncludesOthers = 1 << 1,
+  kCGSSpaceIncludesUser = 1 << 2,
+
+  kCGSAllSpacesMask =
+      kCGSSpaceIncludesCurrent | kCGSSpaceIncludesOthers | kCGSSpaceIncludesUser
+} CGSSpaceMask;
+static NSString* const CGSSpaceIDKey = @"ManagedSpaceID";
+static NSString* const CGSSpacesKey = @"Spaces";
+extern CGSConnection _CGSDefaultConnection(void);
+extern CGError CGSSetWindowTransform(CGSConnection cid, CGSWindow wid,
+                                     CGAffineTransform transform);
+}
+
+#define NS_APPSHELLSERVICE_CONTRACTID "@mozilla.org/appshell/appShellService;1"
+
+NS_IMPL_ISUPPORTS_INHERITED(nsCocoaWindow, Inherited, nsPIWidgetCocoa)
+
+// A note on testing to see if your object is a sheet...
+// |mWindowType == WindowType::Sheet| is true if your gecko nsIWidget is a sheet
+// widget - whether or not the sheet is showing. |[mWindow isSheet]| will return
+// true *only when the sheet is actually showing*. Choose your test wisely.
+
+static void RollUpPopups(nsIRollupListener::AllowAnimations aAllowAnimations =
+                             nsIRollupListener::AllowAnimations::Yes) {
+  if (RefPtr pm = nsXULPopupManager::GetInstance()) {
+    pm->RollupTooltips();
+  }
+
+  nsIRollupListener* rollupListener = nsBaseWidget::GetActiveRollupListener();
+  if (!rollupListener) {
+    return;
+  }
+  if (rollupListener->RollupNativeMenu()) {
+    return;
+  }
+  nsCOMPtr<nsIWidget> rollupWidget = rollupListener->GetRollupWidget();
+  if (!rollupWidget) {
+    return;
+  }
+  nsIRollupListener::RollupOptions options{
+      0, nsIRollupListener::FlushViews::Yes, nullptr, aAllowAnimations};
+  rollupListener->Rollup(options);
+}
+
+nsCocoaWindow::nsCocoaWindow()
+    : mParent(nullptr),
+      mAncestorLink(nullptr),
+      mWindow(nil),
+      mDelegate(nil),
+      mSheetWindowParent(nil),
+      mPopupContentView(nil),
+      mFullscreenTransitionAnimation(nil),
+      mShadowStyle(WindowShadow::None),
+      mBackingScaleFactor(0.0),
+      mAnimationType(nsIWidget::eGenericWindowAnimation),
+      mWindowMadeHere(false),
+      mSheetNeedsShow(false),
+      mSizeMode(nsSizeMode_Normal),
+      mInFullScreenMode(false),
+      mInNativeFullScreenMode(false),
+      mIgnoreOcclusionCount(0),
+      mHasStartedNativeFullscreen(false),
+      mModal(false),
+      mFakeModal(false),
+      mIsAnimationSuppressed(false),
+      mInReportMoveEvent(false),
+      mInResize(false),
+      mWindowTransformIsIdentity(true),
+      mAlwaysOnTop(false),
+      mAspectRatioLocked(false),
+      mNumModalDescendents(0),
+      mWindowAnimationBehavior(NSWindowAnimationBehaviorDefault),
+      mWasShown(false) {
+  // Disable automatic tabbing. We need to do this before we
+  // orderFront any of our windows.
+  [NSWindow setAllowsAutomaticWindowTabbing:NO];
+}
+
+void nsCocoaWindow::DestroyNativeWindow() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mWindow) {
+    return;
+  }
+
+  MOZ_ASSERT(mWindowMadeHere,
+             "We shouldn't be trying to destroy a window we didn't create.");
+
+  // Clear our class state that is keyed off of mWindow. It's our last
+  // chance! This ensures that other nsCocoaWindow instances are not waiting
+  // for us to finish a native transition that will have no listener once
+  // we clear our delegate.
+  EndOurNativeTransition();
+
+  [mWindow releaseJSObjects];
+  // We want to unhook the delegate here because we don't want events
+  // sent to it after this object has been destroyed.
+  [mWindow setDelegate:nil];
+  [mWindow close];
+  mWindow = nil;
+  [mDelegate autorelease];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+nsCocoaWindow::~nsCocoaWindow() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Notify the children that we're gone.  Popup windows (e.g. tooltips) can
+  // have nsChildView children.  'kid' is an nsChildView object if and only if
+  // its 'type' is 'WindowType::Child'.
+  // childView->ResetParent() can change our list of children while it's
+  // being iterated, so the way we iterate the list must allow for this.
+  for (nsIWidget* kid = mLastChild; kid;) {
+    WindowType kidType = kid->GetWindowType();
+    if (kidType == WindowType::Child) {
+      nsChildView* childView = static_cast<nsChildView*>(kid);
+      kid = kid->GetPrevSibling();
+      childView->ResetParent();
+    } else {
+      nsCocoaWindow* childWindow = static_cast<nsCocoaWindow*>(kid);
+      childWindow->mParent = nullptr;
+      childWindow->mAncestorLink = mAncestorLink;
+      kid = kid->GetPrevSibling();
+    }
+  }
+
+  if (mWindow && mWindowMadeHere) {
+    CancelAllTransitions();
+    DestroyNativeWindow();
+  }
+
+  NS_IF_RELEASE(mPopupContentView);
+
+  // Deal with the possiblity that we're being destroyed while running modal.
+  if (mModal) {
+    NS_WARNING("Widget destroyed while running modal!");
+    --gXULModalLevel;
+    NS_ASSERTION(gXULModalLevel >= 0, "Weirdness setting modality!");
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Find the screen that overlaps aRect the most,
+// if none are found default to the mainScreen.
+static NSScreen* FindTargetScreenForRect(const DesktopIntRect& aRect) {
+  NSScreen* targetScreen = [NSScreen mainScreen];
+  NSEnumerator* screenEnum = [[NSScreen screens] objectEnumerator];
+  int largestIntersectArea = 0;
+  while (NSScreen* screen = [screenEnum nextObject]) {
+    DesktopIntRect screenRect =
+        nsCocoaUtils::CocoaRectToGeckoRect([screen visibleFrame]);
+    screenRect = screenRect.Intersect(aRect);
+    int area = screenRect.width * screenRect.height;
+    if (area > largestIntersectArea) {
+      largestIntersectArea = area;
+      targetScreen = screen;
+    }
+  }
+  return targetScreen;
+}
+
+DesktopToLayoutDeviceScale ParentBackingScaleFactor(nsIWidget* aParent,
+                                                    NSView* aParentView) {
+  if (aParent) {
+    return aParent->GetDesktopToDeviceScale();
+  }
+  NSWindow* parentWindow = [aParentView window];
+  if (parentWindow) {
+    return DesktopToLayoutDeviceScale([parentWindow backingScaleFactor]);
+  }
+  return DesktopToLayoutDeviceScale(1.0);
+}
+
+// Returns the screen rectangle for the given widget.
+// Child widgets are positioned relative to this rectangle.
+// Exactly one of the arguments must be non-null.
+static DesktopRect GetWidgetScreenRectForChildren(nsIWidget* aWidget,
+                                                  NSView* aView) {
+  if (aWidget) {
+    mozilla::DesktopToLayoutDeviceScale scale =
+        aWidget->GetDesktopToDeviceScale();
+    if (aWidget->GetWindowType() == WindowType::Child) {
+      return aWidget->GetScreenBounds() / scale;
+    }
+    return aWidget->GetClientBounds() / scale;
+  }
+
+  MOZ_RELEASE_ASSERT(aView);
+
+  // 1. Transform the view rect into window coords.
+  // The returned rect is in "origin bottom-left" coordinates.
+  NSRect rectInWindowCoordinatesOBL = [aView convertRect:[aView bounds]
+                                                  toView:nil];
+
+  // 2. Turn the window-coord rect into screen coords, still origin bottom-left.
+  NSRect rectInScreenCoordinatesOBL =
+      [[aView window] convertRectToScreen:rectInWindowCoordinatesOBL];
+
+  // 3. Convert the NSRect to a DesktopRect. This will convert to coordinates
+  // with the origin in the top left corner of the primary screen.
+  return DesktopRect(
+      nsCocoaUtils::CocoaRectToGeckoRect(rectInScreenCoordinatesOBL));
+}
+
+// aRect here is specified in desktop pixels
+//
+// For child windows (where either aParent or aNativeParent is non-null),
+// aRect.{x,y} are offsets from the origin of the parent window and not an
+// absolute position.
+nsresult nsCocoaWindow::Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                               const DesktopIntRect& aRect,
+                               widget::InitData* aInitData) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // Because the hidden window is created outside of an event loop,
+  // we have to provide an autorelease pool (see bug 559075).
+  nsAutoreleasePool localPool;
+
+  // Set defaults which can be overriden from aInitData in BaseCreate
+  mWindowType = WindowType::TopLevel;
+  mBorderStyle = BorderStyle::Default;
+
+  // Ensure that the toolkit is created.
+  nsToolkit::GetToolkit();
+
+  Inherited::BaseCreate(aParent, aInitData);
+
+  mParent = aParent;
+  mAncestorLink = aParent;
+  mAlwaysOnTop = aInitData->mAlwaysOnTop;
+
+  // If we have a parent widget, the new widget will be offset from the
+  // parent widget by aRect.{x,y}. Otherwise, we'll use aRect for the
+  // new widget coordinates.
+  DesktopIntPoint parentOrigin;
+
+  // Do we have a parent widget?
+  if (aParent || aNativeParent) {
+    DesktopRect parentDesktopRect =
+        GetWidgetScreenRectForChildren(aParent, (NSView*)aNativeParent);
+    parentOrigin = gfx::RoundedToInt(parentDesktopRect.TopLeft());
+  }
+
+  DesktopIntRect widgetRect = aRect + parentOrigin;
+
+  nsresult rv =
+      CreateNativeWindow(nsCocoaUtils::GeckoRectToCocoaRect(widgetRect),
+                         mBorderStyle, false, aInitData->mIsPrivate);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (mWindowType == WindowType::Popup) {
+    // now we can convert widgetRect to device pixels for the window we created,
+    // as the child view expects a rect expressed in the dev pix of its parent
+    LayoutDeviceIntRect devRect =
+        RoundedToInt(aRect * GetDesktopToDeviceScale());
+    return CreatePopupContentView(devRect, aInitData);
+  }
+
+  mIsAnimationSuppressed = aInitData->mIsAnimationSuppressed;
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+nsresult nsCocoaWindow::Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                               const LayoutDeviceIntRect& aRect,
+                               widget::InitData* aInitData) {
+  DesktopIntRect desktopRect = RoundedToInt(
+      aRect / ParentBackingScaleFactor(aParent, (NSView*)aNativeParent));
+  return Create(aParent, aNativeParent, desktopRect, aInitData);
+}
+
+static unsigned int WindowMaskForBorderStyle(BorderStyle aBorderStyle) {
+  bool allOrDefault = (aBorderStyle == BorderStyle::All ||
+                       aBorderStyle == BorderStyle::Default);
+
+  /* Apple's docs on NSWindow styles say that "a window's style mask should
+   * include NSWindowStyleMaskTitled if it includes any of the others [besides
+   * NSWindowStyleMaskBorderless]".  This implies that a borderless window
+   * shouldn't have any other styles than NSWindowStyleMaskBorderless.
+   */
+  if (!allOrDefault && !(aBorderStyle & BorderStyle::Title)) {
+    if (aBorderStyle & BorderStyle::Minimize) {
+      /* It appears that at a minimum, borderless windows can be miniaturizable,
+       * effectively contradicting some of Apple's documentation referenced
+       * above. One such exception is the screen share indicator, see
+       * bug 1742877.
+       */
+      return NSWindowStyleMaskBorderless | NSWindowStyleMaskMiniaturizable;
+    }
+    return NSWindowStyleMaskBorderless;
+  }
+
+  unsigned int mask = NSWindowStyleMaskTitled;
+  if (allOrDefault || aBorderStyle & BorderStyle::Close) {
+    mask |= NSWindowStyleMaskClosable;
+  }
+  if (allOrDefault || aBorderStyle & BorderStyle::Minimize) {
+    mask |= NSWindowStyleMaskMiniaturizable;
+  }
+  if (allOrDefault || aBorderStyle & BorderStyle::ResizeH) {
+    mask |= NSWindowStyleMaskResizable;
+  }
+
+  return mask;
+}
+
+// If aRectIsFrameRect, aRect specifies the frame rect of the new window.
+// Otherwise, aRect.x/y specify the position of the window's frame relative to
+// the bottom of the menubar and aRect.width/height specify the size of the
+// content rect.
+nsresult nsCocoaWindow::CreateNativeWindow(const NSRect& aRect,
+                                           BorderStyle aBorderStyle,
+                                           bool aRectIsFrameRect,
+                                           bool aIsPrivateBrowsing) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // We default to NSWindowStyleMaskBorderless, add features if needed.
+  unsigned int features = NSWindowStyleMaskBorderless;
+
+  // Configure the window we will create based on the window type.
+  switch (mWindowType) {
+    case WindowType::Invisible:
+    case WindowType::Child:
+      break;
+    case WindowType::Popup:
+      if (aBorderStyle != BorderStyle::Default &&
+          mBorderStyle & BorderStyle::Title) {
+        features |= NSWindowStyleMaskTitled;
+        if (aBorderStyle & BorderStyle::Close) {
+          features |= NSWindowStyleMaskClosable;
+        }
+      }
+      break;
+    case WindowType::TopLevel:
+    case WindowType::Dialog:
+      features = WindowMaskForBorderStyle(aBorderStyle);
+      break;
+    case WindowType::Sheet:
+      if (mParent->GetWindowType() != WindowType::Invisible &&
+          aBorderStyle & BorderStyle::ResizeH) {
+        features = NSWindowStyleMaskResizable;
+      } else {
+        features = NSWindowStyleMaskMiniaturizable;
+      }
+      features |= NSWindowStyleMaskTitled;
+      break;
+    default:
+      NS_ERROR("Unhandled window type!");
+      return NS_ERROR_FAILURE;
+  }
+
+  NSRect contentRect;
+
+  if (aRectIsFrameRect) {
+    contentRect = [NSWindow contentRectForFrameRect:aRect styleMask:features];
+  } else {
+    /*
+     * We pass a content area rect to initialize the native Cocoa window. The
+     * content rect we give is the same size as the size we're given by gecko.
+     * The origin we're given for non-popup windows is moved down by the height
+     * of the menu bar so that an origin of (0,100) from gecko puts the window
+     * 100 pixels below the top of the available desktop area. We also move the
+     * origin down by the height of a title bar if it exists. This is so the
+     * origin that gecko gives us for the top-left of  the window turns out to
+     * be the top-left of the window we create. This is how it was done in
+     * Carbon. If it ought to be different we'll probably need to look at all
+     * the callers.
+     *
+     * Note: This means that if you put a secondary screen on top of your main
+     * screen and open a window in the top screen, it'll be incorrectly shifted
+     * down by the height of the menu bar. Same thing would happen in Carbon.
+     *
+     * Note: If you pass a rect with 0,0 for an origin, the window ends up in a
+     * weird place for some reason. This stops that without breaking popups.
+     */
+    // Compensate for difference between frame and content area height (e.g.
+    // title bar).
+    NSRect newWindowFrame = [NSWindow frameRectForContentRect:aRect
+                                                    styleMask:features];
+
+    contentRect = aRect;
+    contentRect.origin.y -= (newWindowFrame.size.height - aRect.size.height);
+
+    if (mWindowType != WindowType::Popup)
+      contentRect.origin.y -= [[NSApp mainMenu] menuBarHeight];
+  }
+
+  // NSLog(@"Top-level window being created at Cocoa rect: %f, %f, %f, %f\n",
+  //       rect.origin.x, rect.origin.y, rect.size.width, rect.size.height);
+
+  Class windowClass = [BaseWindow class];
+  // If we have a titlebar on a top-level window, we want to be able to control
+  // the titlebar color (for unified windows), so use the special ToolbarWindow
+  // class. Note that we need to check the window type because we mark sheets as
+  // having titlebars.
+  if ((mWindowType == WindowType::TopLevel ||
+       mWindowType == WindowType::Dialog) &&
+      (features & NSWindowStyleMaskTitled))
+    windowClass = [ToolbarWindow class];
+  // If we're a popup window we need to use the PopupWindow class.
+  else if (mWindowType == WindowType::Popup)
+    windowClass = [PopupWindow class];
+  // If we're a non-popup borderless window we need to use the
+  // BorderlessWindow class.
+  else if (features == NSWindowStyleMaskBorderless)
+    windowClass = [BorderlessWindow class];
+
+  // Create the window
+  mWindow = [[windowClass alloc] initWithContentRect:contentRect
+                                           styleMask:features
+                                             backing:NSBackingStoreBuffered
+                                               defer:YES];
+
+  // Make sure that window titles don't leak to disk in private browsing mode
+  // due to macOS' resume feature.
+  [mWindow setRestorable:!aIsPrivateBrowsing];
+  if (aIsPrivateBrowsing) {
+    [mWindow disableSnapshotRestoration];
+  }
+
+  // setup our notification delegate. Note that setDelegate: does NOT retain.
+  mDelegate = [[WindowDelegate alloc] initWithGeckoWindow:this];
+  [mWindow setDelegate:mDelegate];
+
+  // Make sure that the content rect we gave has been honored.
+  NSRect wantedFrame = [mWindow frameRectForChildViewRect:contentRect];
+  if (!NSEqualRects([mWindow frame], wantedFrame)) {
+    // This can happen when the window is not on the primary screen.
+    [mWindow setFrame:wantedFrame display:NO];
+  }
+  UpdateBounds();
+
+  if (mWindowType == WindowType::Invisible) {
+    [mWindow setLevel:kCGDesktopWindowLevelKey];
+  }
+
+  if (mWindowType == WindowType::Popup) {
+    SetPopupWindowLevel();
+    [mWindow setBackgroundColor:NSColor.clearColor];
+    [mWindow setOpaque:NO];
+
+    // When multiple spaces are in use and the browser is assigned to a
+    // particular space, override the "Assign To" space and display popups on
+    // the active space. Does not work with multiple displays. See
+    // NeedsRecreateToReshow() for multi-display with multi-space workaround.
+    if (!mAlwaysOnTop) {
+      NSWindowCollectionBehavior behavior = [mWindow collectionBehavior];
+      behavior |= NSWindowCollectionBehaviorMoveToActiveSpace;
+      [mWindow setCollectionBehavior:behavior];
+    }
+  } else {
+    // Non-popup windows are always opaque.
+    [mWindow setOpaque:YES];
+  }
+
+  NSWindowCollectionBehavior newBehavior = [mWindow collectionBehavior];
+  if (mAlwaysOnTop) {
+    [mWindow setLevel:NSFloatingWindowLevel];
+    newBehavior |= NSWindowCollectionBehaviorCanJoinAllSpaces;
+  }
+  [mWindow setCollectionBehavior:newBehavior];
+
+  [mWindow setContentMinSize:NSMakeSize(60, 60)];
+  [mWindow disableCursorRects];
+
+  // Make the window use CoreAnimation from the start, so that we don't
+  // switch from a non-CA window to a CA-window in the middle.
+  [[mWindow contentView] setWantsLayer:YES];
+
+  // Make sure the window starts out not draggable by the background.
+  // We will turn it on as necessary.
+  [mWindow setMovableByWindowBackground:NO];
+
+  [[WindowDataMap sharedWindowDataMap] ensureDataForWindow:mWindow];
+  mWindowMadeHere = true;
+
+  // Make the window respect the global appearance, which follows the
+  // browser.theme.toolbar-theme pref.
+  mWindow.appearanceSource = MOZGlobalAppearance.sharedInstance;
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+nsresult nsCocoaWindow::CreatePopupContentView(const LayoutDeviceIntRect& aRect,
+                                               widget::InitData* aInitData) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // We need to make our content view a ChildView.
+  mPopupContentView = new nsChildView();
+  if (!mPopupContentView) return NS_ERROR_FAILURE;
+
+  NS_ADDREF(mPopupContentView);
+
+  nsIWidget* thisAsWidget = static_cast<nsIWidget*>(this);
+  nsresult rv =
+      mPopupContentView->Create(thisAsWidget, nullptr, aRect, aInitData);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  NSView* contentView = [mWindow contentView];
+  ChildView* childView =
+      (ChildView*)mPopupContentView->GetNativeData(NS_NATIVE_WIDGET);
+  [childView setFrame:[contentView bounds]];
+  [childView setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
+  [contentView addSubview:childView];
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void nsCocoaWindow::Destroy() {
+  if (mOnDestroyCalled) return;
+  mOnDestroyCalled = true;
+
+  // SetFakeModal(true) is called for non-modal window opened by modal window.
+  // On Cocoa, it needs corresponding SetFakeModal(false) on destroy to restore
+  // ancestor windows' state.
+  if (mFakeModal) {
+    SetFakeModal(false);
+  }
+
+  // If we don't hide here we run into problems with panels, this is not ideal.
+  // (Bug 891424)
+  Show(false);
+
+  if (mPopupContentView) mPopupContentView->Destroy();
+
+  if (mFullscreenTransitionAnimation) {
+    [mFullscreenTransitionAnimation stopAnimation];
+    ReleaseFullscreenTransitionAnimation();
+  }
+
+  nsBaseWidget::Destroy();
+  // nsBaseWidget::Destroy() calls GetParent()->RemoveChild(this). But we
+  // don't implement GetParent(), so we need to do the equivalent here.
+  if (mParent) {
+    mParent->RemoveChild(this);
+  }
+  nsBaseWidget::OnDestroy();
+
+  if (mInFullScreenMode && !mInNativeFullScreenMode) {
+    // Keep these calls balanced for emulated fullscreen.
+    nsCocoaUtils::HideOSChromeOnScreen(false);
+  }
+
+  // Destroy the native window here (and not wait for that to happen in our
+  // destructor). Otherwise this might not happen for several seconds because
+  // at least one object holding a reference to ourselves is usually waiting
+  // to be garbage-collected.
+  if (mWindow && mWindowMadeHere) {
+    CancelAllTransitions();
+    DestroyNativeWindow();
+  }
+}
+
+nsIWidget* nsCocoaWindow::GetSheetWindowParent(void) {
+  if (mWindowType != WindowType::Sheet) return nullptr;
+  nsCocoaWindow* parent = static_cast<nsCocoaWindow*>(mParent);
+  while (parent && (parent->mWindowType == WindowType::Sheet))
+    parent = static_cast<nsCocoaWindow*>(parent->mParent);
+  return parent;
+}
+
+void* nsCocoaWindow::GetNativeData(uint32_t aDataType) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  void* retVal = nullptr;
+
+  switch (aDataType) {
+    // to emulate how windows works, we always have to return a NSView
+    // for NS_NATIVE_WIDGET
+    case NS_NATIVE_WIDGET:
+      retVal = [mWindow contentView];
+      break;
+
+    case NS_NATIVE_WINDOW:
+      retVal = mWindow;
+      break;
+
+    case NS_NATIVE_GRAPHIC:
+      // There isn't anything that makes sense to return here,
+      // and it doesn't matter so just return nullptr.
+      NS_ERROR("Requesting NS_NATIVE_GRAPHIC on a top-level window!");
+      break;
+    case NS_RAW_NATIVE_IME_CONTEXT: {
+      retVal = GetPseudoIMEContext();
+      if (retVal) {
+        break;
+      }
+      NSView* view = mWindow ? [mWindow contentView] : nil;
+      if (view) {
+        retVal = [view inputContext];
+      }
+      // If inputContext isn't available on this window, return this window's
+      // pointer instead of nullptr since if this returns nullptr,
+      // IMEStateManager cannot manage composition with TextComposition
+      // instance.  Although, this case shouldn't occur.
+      if (NS_WARN_IF(!retVal)) {
+        retVal = this;
+      }
+      break;
+    }
+  }
+
+  return retVal;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nullptr);
+}
+
+bool nsCocoaWindow::IsVisible() const {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return (mWindow && ([mWindow isVisibleOrBeingShown] || mSheetNeedsShow));
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
+
+void nsCocoaWindow::SetModal(bool aState) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Unlike many functions here, we explicitly *do not check* for the
+  // existence of mWindow. This is to ensure that calls to SetModal have
+  // no early exits and always update state. That way, if the calls are
+  // balanced, we get expected behavior even if the native window has
+  // been destroyed during the modal period. Within this function, all
+  // the calls to mWindow will resolve even if mWindow is nil (as is
+  // guaranteed by Objective-C). And since those calls are only concerned
+  // with changing mWindow appearance/level, it's fine for them to be
+  // no-ops if mWindow has already been destroyed.
+
+  // This is used during startup (outside the event loop) when creating
+  // the add-ons compatibility checking dialog and the profile manager UI;
+  // therefore, it needs to provide an autorelease pool to avoid cocoa
+  // objects leaking.
+  nsAutoreleasePool localPool;
+
+  mModal = aState;
+  nsCocoaWindow* ancestor = static_cast<nsCocoaWindow*>(mAncestorLink);
+  if (aState) {
+    ++gXULModalLevel;
+    // When a non-sheet window gets "set modal", make the window(s) that it
+    // appears over behave as they should.  We can't rely on native methods to
+    // do this, for the following reason:  The OS runs modal non-sheet windows
+    // in an event loop (using [NSApplication runModalForWindow:] or similar
+    // methods) that's incompatible with the modal event loop in AppWindow::
+    // ShowModal() (each of these event loops is "exclusive", and can't run at
+    // the same time as other (similar) event loops).
+    if (mWindowType != WindowType::Sheet) {
+      while (ancestor) {
+        if (ancestor->mNumModalDescendents++ == 0) {
+          NSWindow* aWindow = ancestor->GetCocoaWindow();
+          if (ancestor->mWindowType != WindowType::Invisible) {
+            [[aWindow standardWindowButton:NSWindowCloseButton] setEnabled:NO];
+            [[aWindow standardWindowButton:NSWindowMiniaturizeButton]
+                setEnabled:NO];
+            [[aWindow standardWindowButton:NSWindowZoomButton] setEnabled:NO];
+          }
+        }
+        ancestor = static_cast<nsCocoaWindow*>(ancestor->mParent);
+      }
+      [mWindow setLevel:NSModalPanelWindowLevel];
+      nsCocoaWindowList* windowList = new nsCocoaWindowList;
+      if (windowList) {
+        windowList->window = this;  // Don't ADDREF
+        windowList->prev = gGeckoAppModalWindowList;
+        gGeckoAppModalWindowList = windowList;
+      }
+    }
+  } else {
+    --gXULModalLevel;
+    NS_ASSERTION(gXULModalLevel >= 0,
+                 "Mismatched call to nsCocoaWindow::SetModal(false)!");
+    if (mWindowType != WindowType::Sheet) {
+      while (ancestor) {
+        if (--ancestor->mNumModalDescendents == 0) {
+          NSWindow* aWindow = ancestor->GetCocoaWindow();
+          if (ancestor->mWindowType != WindowType::Invisible) {
+            [[aWindow standardWindowButton:NSWindowCloseButton] setEnabled:YES];
+            [[aWindow standardWindowButton:NSWindowMiniaturizeButton]
+                setEnabled:YES];
+            [[aWindow standardWindowButton:NSWindowZoomButton] setEnabled:YES];
+          }
+        }
+        NS_ASSERTION(ancestor->mNumModalDescendents >= 0,
+                     "Widget hierarchy changed while modal!");
+        ancestor = static_cast<nsCocoaWindow*>(ancestor->mParent);
+      }
+      if (gGeckoAppModalWindowList) {
+        NS_ASSERTION(gGeckoAppModalWindowList->window == this,
+                     "Widget hierarchy changed while modal!");
+        nsCocoaWindowList* saved = gGeckoAppModalWindowList;
+        gGeckoAppModalWindowList = gGeckoAppModalWindowList->prev;
+        delete saved;  // "window" not ADDREFed
+      }
+      if (mWindowType == WindowType::Popup)
+        SetPopupWindowLevel();
+      else
+        [mWindow setLevel:NSNormalWindowLevel];
+    }
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::SetFakeModal(bool aState) {
+  mFakeModal = aState;
+  SetModal(aState);
+}
+
+bool nsCocoaWindow::IsRunningAppModal() { return [NSApp _isRunningAppModal]; }
+
+// Hide or show this window
+void nsCocoaWindow::Show(bool bState) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mWindow) return;
+
+  if (!mSheetNeedsShow) {
+    // Early exit if our current visibility state is already the requested
+    // state.
+    if (bState == ([mWindow isVisible] || [mWindow isBeingShown])) {
+      return;
+    }
+  }
+
+  [mWindow setBeingShown:bState];
+  if (bState && !mWasShown) {
+    mWasShown = true;
+  }
+
+  nsIWidget* parentWidget = mParent;
+  nsCOMPtr<nsPIWidgetCocoa> piParentWidget(do_QueryInterface(parentWidget));
+  NSWindow* nativeParentWindow =
+      (parentWidget) ? (NSWindow*)parentWidget->GetNativeData(NS_NATIVE_WINDOW)
+                     : nil;
+
+  if (bState && !mBounds.IsEmpty()) {
+    // If we had set the activationPolicy to accessory, then right now we won't
+    // have a dock icon. Make sure that we undo that and show a dock icon now
+    // that we're going to show a window.
+    if ([NSApp activationPolicy] != NSApplicationActivationPolicyRegular) {
+      [NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
+      PR_SetEnv("MOZ_APP_NO_DOCK=");
+    }
+
+    // Don't try to show a popup when the parent isn't visible or is minimized.
+    if (mWindowType == WindowType::Popup && nativeParentWindow) {
+      if (![nativeParentWindow isVisible] ||
+          [nativeParentWindow isMiniaturized]) {
+        return;
+      }
+    }
+
+    if (mPopupContentView) {
+      // Ensure our content view is visible. We never need to hide it.
+      mPopupContentView->Show(true);
+    }
+
+    if (mWindowType == WindowType::Sheet) {
+      // bail if no parent window (its basically what we do in Carbon)
+      if (!nativeParentWindow || !piParentWidget) return;
+
+      NSWindow* topNonSheetWindow = nativeParentWindow;
+
+      // If this sheet is the child of another sheet, hide the parent so that
+      // this sheet can be displayed. Leave the parent mSheetNeedsShow alone,
+      // that is only used to handle sibling sheet contention. The parent will
+      // return once there are no more child sheets.
+      bool parentIsSheet = false;
+      if (NS_SUCCEEDED(piParentWidget->GetIsSheet(&parentIsSheet)) &&
+          parentIsSheet) {
+        piParentWidget->GetSheetWindowParent(&topNonSheetWindow);
+#ifdef MOZ_THUNDERBIRD
+        [NSApp endSheet:nativeParentWindow];
+#else
+        [nativeParentWindow.sheetParent endSheet:nativeParentWindow];
+#endif
+      }
+
+      nsCOMPtr<nsIWidget> sheetShown;
+      if (NS_SUCCEEDED(piParentWidget->GetChildSheet(
+              true, getter_AddRefs(sheetShown))) &&
+          (!sheetShown || sheetShown == this)) {
+        // If this sheet is already the sheet actually being shown, don't
+        // tell it to show again. Otherwise the number of calls to
+#ifdef MOZ_THUNDERBIRD
+        // [NSApp beginSheet...] won't match up with [NSApp endSheet...].
+#else
+        // [NSWindow beginSheet...] won't match up with [NSWindow endSheet...].
+#endif
+        if (![mWindow isVisible]) {
+          mSheetNeedsShow = false;
+          mSheetWindowParent = topNonSheetWindow;
+#ifdef MOZ_THUNDERBIRD
+          // Only set contextInfo if our parent isn't a sheet.
+          NSWindow* contextInfo = parentIsSheet ? nil : mSheetWindowParent;
+          [TopLevelWindowData deactivateInWindow:mSheetWindowParent];
+          [NSApp beginSheet:mWindow
+              modalForWindow:mSheetWindowParent
+               modalDelegate:mDelegate
+              didEndSelector:@selector(didEndSheet:returnCode:contextInfo:)
+                 contextInfo:contextInfo];
+#else
+          NSWindow* sheet = mWindow;
+          NSWindow* nonSheetParent = parentIsSheet ? nil : mSheetWindowParent;
+          [TopLevelWindowData deactivateInWindow:mSheetWindowParent];
+          [mSheetWindowParent beginSheet:sheet
+                       completionHandler:^(NSModalResponse returnCode) {
+                         // Note: 'nonSheetParent' (if it is set) is the window
+                         // that is the parent of the sheet. If it's set,
+                         // 'nonSheetParent' is always the top- level window,
+                         // not another sheet itself.  But 'nonSheetParent' is
+                         // nil if our parent window is also a sheet -- in that
+                         // case we shouldn't send the top-level window any
+                         // activate events (because it's our parent window that
+                         // needs to get these events, not the top-level
+                         // window).
+                         [TopLevelWindowData deactivateInWindow:sheet];
+                         [sheet orderOut:nil];
+                         if (nonSheetParent) {
+                           [TopLevelWindowData activateInWindow:nonSheetParent];
+                         }
+                       }];
+#endif
+          [TopLevelWindowData activateInWindow:mWindow];
+          SendSetZLevelEvent();
+        }
+      } else {
+        // A sibling of this sheet is active, don't show this sheet yet.
+        // When the active sheet hides, its brothers and sisters that have
+        // mSheetNeedsShow set will have their opportunities to display.
+        mSheetNeedsShow = true;
+      }
+    } else if (mWindowType == WindowType::Popup) {
+      // For reasons that aren't yet clear, calls to [NSWindow orderFront:] or
+      // [NSWindow makeKeyAndOrderFront:] can sometimes trigger "Error (1000)
+      // creating CGSWindow", which in turn triggers an internal inconsistency
+      // NSException.  These errors shouldn't be fatal.  So we need to wrap
+      // calls to ...orderFront: in TRY blocks.  See bmo bug 470864.
+      NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+      [[mWindow contentView] setNeedsDisplay:YES];
+      [mWindow orderFront:nil];
+      NS_OBJC_END_TRY_IGNORE_BLOCK;
+      SendSetZLevelEvent();
+      // If our popup window is a non-native context menu, tell the OS (and
+      // other programs) that a menu has opened.  This is how the OS knows to
+      // close other programs' context menus when ours open.
+      if ([mWindow isKindOfClass:[PopupWindow class]] &&
+          [(PopupWindow*)mWindow isContextMenu]) {
+        [[NSDistributedNotificationCenter defaultCenter]
+            postNotificationName:
+                @"com.apple.HIToolbox.beginMenuTrackingNotification"
+                          object:@"org.mozilla.gecko.PopupWindow"];
+      }
+
+      // If a parent window was supplied and this is a popup at the parent
+      // level, set its child window. This will cause the child window to
+      // appear above the parent and move when the parent does. Setting this
+      // needs to happen after the _setWindowNumber calls above, otherwise the
+      // window doesn't focus properly.
+      if (nativeParentWindow && mPopupLevel == PopupLevel::Parent)
+        [nativeParentWindow addChildWindow:mWindow ordered:NSWindowAbove];
+    } else {
+      NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+      if (mWindowType == WindowType::TopLevel &&
+          [mWindow respondsToSelector:@selector(setAnimationBehavior:)]) {
+        NSWindowAnimationBehavior behavior;
+        if (mIsAnimationSuppressed) {
+          behavior = NSWindowAnimationBehaviorNone;
+        } else {
+          switch (mAnimationType) {
+            case nsIWidget::eDocumentWindowAnimation:
+              behavior = NSWindowAnimationBehaviorDocumentWindow;
+              break;
+            default:
+              MOZ_FALLTHROUGH_ASSERT("unexpected mAnimationType value");
+            case nsIWidget::eGenericWindowAnimation:
+              behavior = NSWindowAnimationBehaviorDefault;
+              break;
+          }
+        }
+        [mWindow setAnimationBehavior:behavior];
+        mWindowAnimationBehavior = behavior;
+      }
+
+      // We don't want alwaysontop windows to pull focus when they're opened,
+      // as these tend to be for peripheral indicators and displays.
+      if (mAlwaysOnTop) {
+        [mWindow orderFront:nil];
+      } else {
+        [mWindow makeKeyAndOrderFront:nil];
+      }
+      NS_OBJC_END_TRY_IGNORE_BLOCK;
+      SendSetZLevelEvent();
+    }
+  } else {
+    // roll up any popups if a top-level window is going away
+    if (mWindowType == WindowType::TopLevel ||
+        mWindowType == WindowType::Dialog) {
+      RollUpPopups();
+    }
+
+    // now get rid of the window/sheet
+    if (mWindowType == WindowType::Sheet) {
+      if (mSheetNeedsShow) {
+        // This is an attempt to hide a sheet that never had a chance to
+        // be shown. There's nothing to do other than make sure that it
+        // won't show.
+        mSheetNeedsShow = false;
+      } else {
+        // get sheet's parent *before* hiding the sheet (which breaks the
+        // linkage)
+        NSWindow* sheetParent = mSheetWindowParent;
+
+        // hide the sheet
+#ifdef MOZ_THUNDERBIRD
+        [NSApp endSheet:mWindow];
+#else
+        [mSheetWindowParent endSheet:mWindow];
+#endif
+        [TopLevelWindowData deactivateInWindow:mWindow];
+
+        nsCOMPtr<nsIWidget> siblingSheetToShow;
+        bool parentIsSheet = false;
+
+        if (nativeParentWindow && piParentWidget &&
+            NS_SUCCEEDED(piParentWidget->GetChildSheet(
+                false, getter_AddRefs(siblingSheetToShow))) &&
+            siblingSheetToShow) {
+          // First, give sibling sheets an opportunity to show.
+          siblingSheetToShow->Show(true);
+        } else if (nativeParentWindow && piParentWidget &&
+                   NS_SUCCEEDED(piParentWidget->GetIsSheet(&parentIsSheet)) &&
+                   parentIsSheet) {
+#ifdef MOZ_THUNDERBIRD
+          // Only set contextInfo if the parent of the parent sheet we're about
+          // to restore isn't itself a sheet.
+          NSWindow* contextInfo = sheetParent;
+#else
+          // Only set nonSheetGrandparent if the parent of the parent sheet
+          // we're about to restore isn't itself a sheet.
+          NSWindow* nonSheetGrandparent = sheetParent;
+#endif
+          nsIWidget* grandparentWidget = nil;
+          if (NS_SUCCEEDED(piParentWidget->GetRealParent(&grandparentWidget)) &&
+              grandparentWidget) {
+            nsCOMPtr<nsPIWidgetCocoa> piGrandparentWidget(
+                do_QueryInterface(grandparentWidget));
+            bool grandparentIsSheet = false;
+            if (piGrandparentWidget &&
+                NS_SUCCEEDED(
+                    piGrandparentWidget->GetIsSheet(&grandparentIsSheet)) &&
+                grandparentIsSheet) {
+#ifdef MOZ_THUNDERBIRD
+              contextInfo = nil;
+#else
+              nonSheetGrandparent = nil;
+#endif
+            }
+          }
+          // If there are no sibling sheets, but the parent is a sheet, restore
+          // it.  It wasn't sent any deactivate events when it was hidden, so
+          // don't call through Show, just let the OS put it back up.
+#ifdef MOZ_THUNDERBIRD
+          [NSApp beginSheet:nativeParentWindow
+              modalForWindow:sheetParent
+               modalDelegate:[nativeParentWindow delegate]
+              didEndSelector:@selector(didEndSheet:returnCode:contextInfo:)
+                 contextInfo:contextInfo];
+#else
+          [nativeParentWindow
+                     beginSheet:sheetParent
+              completionHandler:^(NSModalResponse returnCode) {
+                // Note: 'nonSheetGrandparent' (if it is set) is the window that
+                // is the parent of sheetParent. If it's set,
+                // 'nonSheetGrandparent' is always the top-level window, not
+                // another sheet itself.  But 'nonSheetGrandparent' is nil if
+                // our parent window is also a sheet -- in that case we
+                // shouldn't send the top-level window any activate events
+                // (because it's our parent window that needs to get these
+                // events, not the top-level window).
+                [TopLevelWindowData deactivateInWindow:sheetParent];
+                [sheetParent orderOut:nil];
+                if (nonSheetGrandparent) {
+                  [TopLevelWindowData activateInWindow:nonSheetGrandparent];
+                }
+              }];
+#endif
+        } else {
+          // Sheet, that was hard.  No more siblings or parents, going back
+          // to a real window.
+          NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+          [sheetParent makeKeyAndOrderFront:nil];
+          NS_OBJC_END_TRY_IGNORE_BLOCK;
+        }
+        SendSetZLevelEvent();
+      }
+    } else {
+      // If the window is a popup window with a parent window we need to
+      // unhook it here before ordering it out. When you order out the child
+      // of a window it hides the parent window.
+      if (mWindowType == WindowType::Popup && nativeParentWindow)
+        [nativeParentWindow removeChildWindow:mWindow];
+
+      [mWindow orderOut:nil];
+
+      // If our popup window is a non-native context menu, tell the OS (and
+      // other programs) that a menu has closed.
+      if ([mWindow isKindOfClass:[PopupWindow class]] &&
+          [(PopupWindow*)mWindow isContextMenu]) {
+        [[NSDistributedNotificationCenter defaultCenter]
+            postNotificationName:
+                @"com.apple.HIToolbox.endMenuTrackingNotification"
+                          object:@"org.mozilla.gecko.PopupWindow"];
+      }
+    }
+  }
+
+  [mWindow setBeingShown:NO];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Work around a problem where with multiple displays and multiple spaces
+// enabled, where the browser is assigned to a single display or space, popup
+// windows that are reshown after being hidden with [NSWindow orderOut] show on
+// the assigned space even when opened from another display. Apply the
+// workaround whenever more than one display is enabled.
+bool nsCocoaWindow::NeedsRecreateToReshow() {
+  // Limit the workaround to popup windows because only they need to override
+  // the "Assign To" setting. i.e., to display where the parent window is.
+  return (mWindowType == WindowType::Popup) && mWasShown &&
+         ([[NSScreen screens] count] > 1);
+}
+
+WindowRenderer* nsCocoaWindow::GetWindowRenderer() {
+  if (mPopupContentView) {
+    return mPopupContentView->GetWindowRenderer();
+  }
+  return nullptr;
+}
+
+TransparencyMode nsCocoaWindow::GetTransparencyMode() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return (!mWindow || [mWindow isOpaque]) ? TransparencyMode::Opaque
+                                          : TransparencyMode::Transparent;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(TransparencyMode::Opaque);
+}
+
+// This is called from nsMenuPopupFrame when making a popup transparent.
+void nsCocoaWindow::SetTransparencyMode(TransparencyMode aMode) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mWindow) {
+    return;
+  }
+
+  BOOL isTransparent = aMode == TransparencyMode::Transparent;
+  BOOL currentTransparency = !mWindow.isOpaque;
+  if (isTransparent == currentTransparency) {
+    return;
+  }
+  [mWindow setOpaque:!isTransparent];
+  [mWindow setBackgroundColor:(isTransparent ? NSColor.clearColor
+                                             : NSColor.whiteColor)];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::Enable(bool aState) {}
+
+bool nsCocoaWindow::IsEnabled() const { return true; }
+
+void nsCocoaWindow::ConstrainPosition(DesktopIntPoint& aPoint) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mWindow || ![mWindow screen]) {
+    return;
+  }
+
+  nsIntRect screenBounds;
+
+  int32_t width, height;
+
+  NSRect frame = [mWindow frame];
+
+  // zero size rects confuse the screen manager
+  width = std::max<int32_t>(frame.size.width, 1);
+  height = std::max<int32_t>(frame.size.height, 1);
+
+  nsCOMPtr<nsIScreenManager> screenMgr =
+      do_GetService("@mozilla.org/gfx/screenmanager;1");
+  if (screenMgr) {
+    nsCOMPtr<nsIScreen> screen;
+    screenMgr->ScreenForRect(aPoint.x, aPoint.y, width, height,
+                             getter_AddRefs(screen));
+
+    if (screen) {
+      screen->GetRectDisplayPix(&(screenBounds.x), &(screenBounds.y),
+                                &(screenBounds.width), &(screenBounds.height));
+    }
+  }
+
+  if (aPoint.x < screenBounds.x) {
+    aPoint.x = screenBounds.x;
+  } else if (aPoint.x >= screenBounds.x + screenBounds.width - width) {
+    aPoint.x = screenBounds.x + screenBounds.width - width;
+  }
+
+  if (aPoint.y < screenBounds.y) {
+    aPoint.y = screenBounds.y;
+  } else if (aPoint.y >= screenBounds.y + screenBounds.height - height) {
+    aPoint.y = screenBounds.y + screenBounds.height - height;
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::SetSizeConstraints(const SizeConstraints& aConstraints) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Popups can be smaller than (32, 32)
+  NSRect rect = (mWindowType == WindowType::Popup)
+                    ? NSZeroRect
+                    : NSMakeRect(0.0, 0.0, 32, 32);
+  rect = [mWindow frameRectForChildViewRect:rect];
+
+  SizeConstraints c = aConstraints;
+
+  if (c.mScale.scale == MOZ_WIDGET_INVALID_SCALE) {
+    c.mScale.scale = BackingScaleFactor();
+  }
+
+  c.mMinSize.width = std::max(
+      nsCocoaUtils::CocoaPointsToDevPixels(rect.size.width, c.mScale.scale),
+      c.mMinSize.width);
+  c.mMinSize.height = std::max(
+      nsCocoaUtils::CocoaPointsToDevPixels(rect.size.height, c.mScale.scale),
+      c.mMinSize.height);
+
+  NSSize minSize = {
+      nsCocoaUtils::DevPixelsToCocoaPoints(c.mMinSize.width, c.mScale.scale),
+      nsCocoaUtils::DevPixelsToCocoaPoints(c.mMinSize.height, c.mScale.scale)};
+  [mWindow setMinSize:minSize];
+
+  c.mMaxSize.width = std::max(
+      nsCocoaUtils::CocoaPointsToDevPixels(c.mMaxSize.width, c.mScale.scale),
+      c.mMaxSize.width);
+  c.mMaxSize.height = std::max(
+      nsCocoaUtils::CocoaPointsToDevPixels(c.mMaxSize.height, c.mScale.scale),
+      c.mMaxSize.height);
+
+  NSSize maxSize = {
+      c.mMaxSize.width == NS_MAXSIZE ? FLT_MAX
+                                     : nsCocoaUtils::DevPixelsToCocoaPoints(
+                                           c.mMaxSize.width, c.mScale.scale),
+      c.mMaxSize.height == NS_MAXSIZE ? FLT_MAX
+                                      : nsCocoaUtils::DevPixelsToCocoaPoints(
+                                            c.mMaxSize.height, c.mScale.scale)};
+  [mWindow setMaxSize:maxSize];
+
+  nsBaseWidget::SetSizeConstraints(c);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Coordinates are desktop pixels
+void nsCocoaWindow::Move(double aX, double aY) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mWindow) {
+    return;
+  }
+
+  // The point we have is in Gecko coordinates (origin top-left). Convert
+  // it to Cocoa ones (origin bottom-left).
+  NSPoint coord = {
+      static_cast<float>(aX),
+      static_cast<float>(nsCocoaUtils::FlippedScreenY(NSToIntRound(aY)))};
+
+  NSRect frame = [mWindow frame];
+  if (frame.origin.x != coord.x ||
+      frame.origin.y + frame.size.height != coord.y) {
+    [mWindow setFrameTopLeftPoint:coord];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::SetSizeMode(nsSizeMode aMode) {
+  if (aMode == nsSizeMode_Normal) {
+    QueueTransition(TransitionType::Windowed);
+  } else if (aMode == nsSizeMode_Minimized) {
+    QueueTransition(TransitionType::Miniaturize);
+  } else if (aMode == nsSizeMode_Maximized) {
+    QueueTransition(TransitionType::Zoom);
+  } else if (aMode == nsSizeMode_Fullscreen) {
+    MakeFullScreen(true);
+  }
+}
+
+// The (work)space switching implementation below was inspired by Phoenix:
+// https://github.com/kasper/phoenix/tree/d6c877f62b30a060dff119d8416b0934f76af534
+// License: MIT.
+
+// Runtime `CGSGetActiveSpace` library function feature detection.
+typedef CGSSpaceID (*CGSGetActiveSpaceFunc)(CGSConnection cid);
+static CGSGetActiveSpaceFunc GetCGSGetActiveSpaceFunc() {
+  static CGSGetActiveSpaceFunc func = nullptr;
+  static bool lookedUpFunc = false;
+  if (!lookedUpFunc) {
+    func = (CGSGetActiveSpaceFunc)dlsym(RTLD_DEFAULT, "CGSGetActiveSpace");
+    lookedUpFunc = true;
+  }
+  return func;
+}
+// Runtime `CGSCopyManagedDisplaySpaces` library function feature detection.
+typedef CFArrayRef (*CGSCopyManagedDisplaySpacesFunc)(CGSConnection cid);
+static CGSCopyManagedDisplaySpacesFunc GetCGSCopyManagedDisplaySpacesFunc() {
+  static CGSCopyManagedDisplaySpacesFunc func = nullptr;
+  static bool lookedUpFunc = false;
+  if (!lookedUpFunc) {
+    func = (CGSCopyManagedDisplaySpacesFunc)dlsym(
+        RTLD_DEFAULT, "CGSCopyManagedDisplaySpaces");
+    lookedUpFunc = true;
+  }
+  return func;
+}
+// Runtime `CGSCopySpacesForWindows` library function feature detection.
+typedef CFArrayRef (*CGSCopySpacesForWindowsFunc)(CGSConnection cid,
+                                                  CGSSpaceMask mask,
+                                                  CFArrayRef windowIDs);
+static CGSCopySpacesForWindowsFunc GetCGSCopySpacesForWindowsFunc() {
+  static CGSCopySpacesForWindowsFunc func = nullptr;
+  static bool lookedUpFunc = false;
+  if (!lookedUpFunc) {
+    func = (CGSCopySpacesForWindowsFunc)dlsym(RTLD_DEFAULT,
+                                              "CGSCopySpacesForWindows");
+    lookedUpFunc = true;
+  }
+  return func;
+}
+// Runtime `CGSAddWindowsToSpaces` library function feature detection.
+typedef void (*CGSAddWindowsToSpacesFunc)(CGSConnection cid,
+                                          CFArrayRef windowIDs,
+                                          CFArrayRef spaceIDs);
+static CGSAddWindowsToSpacesFunc GetCGSAddWindowsToSpacesFunc() {
+  static CGSAddWindowsToSpacesFunc func = nullptr;
+  static bool lookedUpFunc = false;
+  if (!lookedUpFunc) {
+    func =
+        (CGSAddWindowsToSpacesFunc)dlsym(RTLD_DEFAULT, "CGSAddWindowsToSpaces");
+    lookedUpFunc = true;
+  }
+  return func;
+}
+// Runtime `CGSRemoveWindowsFromSpaces` library function feature detection.
+typedef void (*CGSRemoveWindowsFromSpacesFunc)(CGSConnection cid,
+                                               CFArrayRef windowIDs,
+                                               CFArrayRef spaceIDs);
+static CGSRemoveWindowsFromSpacesFunc GetCGSRemoveWindowsFromSpacesFunc() {
+  static CGSRemoveWindowsFromSpacesFunc func = nullptr;
+  static bool lookedUpFunc = false;
+  if (!lookedUpFunc) {
+    func = (CGSRemoveWindowsFromSpacesFunc)dlsym(RTLD_DEFAULT,
+                                                 "CGSRemoveWindowsFromSpaces");
+    lookedUpFunc = true;
+  }
+  return func;
+}
+
+void nsCocoaWindow::GetWorkspaceID(nsAString& workspaceID) {
+  workspaceID.Truncate();
+  int32_t sid = GetWorkspaceID();
+  if (sid != 0) {
+    workspaceID.AppendInt(sid);
+  }
+}
+
+int32_t nsCocoaWindow::GetWorkspaceID() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Mac OSX space IDs start at '1' (default space), so '0' means 'unknown',
+  // effectively.
+  CGSSpaceID sid = 0;
+
+  CGSCopySpacesForWindowsFunc CopySpacesForWindows =
+      GetCGSCopySpacesForWindowsFunc();
+  if (!CopySpacesForWindows) {
+    return sid;
+  }
+
+  CGSConnection cid = _CGSDefaultConnection();
+  // Fetch all spaces that this window belongs to (in order).
+  NSArray<NSNumber*>* spaceIDs = CFBridgingRelease(CopySpacesForWindows(
+      cid, kCGSAllSpacesMask,
+      (__bridge CFArrayRef) @[ @([mWindow windowNumber]) ]));
+  if ([spaceIDs count]) {
+    // When spaces are found, return the first one.
+    // We don't support a single window painted across multiple places for now.
+    sid = [spaceIDs[0] integerValue];
+  } else {
+    // Fall back to the workspace that's currently active, which is '1' in the
+    // common case.
+    CGSGetActiveSpaceFunc GetActiveSpace = GetCGSGetActiveSpaceFunc();
+    if (GetActiveSpace) {
+      sid = GetActiveSpace(cid);
+    }
+  }
+
+  return sid;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::MoveToWorkspace(const nsAString& workspaceIDStr) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if ([NSScreen screensHaveSeparateSpaces] && [[NSScreen screens] count] > 1) {
+    // We don't support moving to a workspace when the user has this option
+    // enabled in Mission Control.
+    return;
+  }
+
+  nsresult rv = NS_OK;
+  int32_t workspaceID = workspaceIDStr.ToInteger(&rv);
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  CGSConnection cid = _CGSDefaultConnection();
+  int32_t currentSpace = GetWorkspaceID();
+  // If an empty workspace ID is passed in (not valid on OSX), or when the
+  // window is already on this workspace, we don't need to do anything.
+  if (!workspaceID || workspaceID == currentSpace) {
+    return;
+  }
+
+  CGSCopyManagedDisplaySpacesFunc CopyManagedDisplaySpaces =
+      GetCGSCopyManagedDisplaySpacesFunc();
+  CGSAddWindowsToSpacesFunc AddWindowsToSpaces = GetCGSAddWindowsToSpacesFunc();
+  CGSRemoveWindowsFromSpacesFunc RemoveWindowsFromSpaces =
+      GetCGSRemoveWindowsFromSpacesFunc();
+  if (!CopyManagedDisplaySpaces || !AddWindowsToSpaces ||
+      !RemoveWindowsFromSpaces) {
+    return;
+  }
+
+  // Fetch an ordered list of all known spaces.
+  NSArray* displaySpacesInfo = CFBridgingRelease(CopyManagedDisplaySpaces(cid));
+  // When we found the space we're looking for, we can bail out of the loop
+  // early, which this local variable is used for.
+  BOOL found = false;
+  for (NSDictionary<NSString*, id>* spacesInfo in displaySpacesInfo) {
+    NSArray<NSNumber*>* sids =
+        [spacesInfo[CGSSpacesKey] valueForKey:CGSSpaceIDKey];
+    for (NSNumber* sid in sids) {
+      // If we found our space in the list, we're good to go and can jump out of
+      // this loop.
+      if ((int)[sid integerValue] == workspaceID) {
+        found = true;
+        break;
+      }
+    }
+    if (found) {
+      break;
+    }
+  }
+
+  // We were unable to find the space to correspond with the workspaceID as
+  // requested, so let's bail out.
+  if (!found) {
+    return;
+  }
+
+  // First we add the window to the appropriate space.
+  AddWindowsToSpaces(cid, (__bridge CFArrayRef) @[ @([mWindow windowNumber]) ],
+                     (__bridge CFArrayRef) @[ @(workspaceID) ]);
+  // Then we remove the window from the active space.
+  RemoveWindowsFromSpaces(cid,
+                          (__bridge CFArrayRef) @[ @([mWindow windowNumber]) ],
+                          (__bridge CFArrayRef) @[ @(currentSpace) ]);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::SuppressAnimation(bool aSuppress) {
+  if ([mWindow respondsToSelector:@selector(setAnimationBehavior:)]) {
+    if (aSuppress) {
+      [mWindow setIsAnimationSuppressed:YES];
+      [mWindow setAnimationBehavior:NSWindowAnimationBehaviorNone];
+    } else {
+      [mWindow setIsAnimationSuppressed:NO];
+      [mWindow setAnimationBehavior:mWindowAnimationBehavior];
+    }
+  }
+}
+
+// This has to preserve the window's frame bounds.
+// This method requires (as does the Windows impl.) that you call Resize shortly
+// after calling HideWindowChrome. See bug 498835 for fixing this.
+void nsCocoaWindow::HideWindowChrome(bool aShouldHide) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mWindow || !mWindowMadeHere ||
+      (mWindowType != WindowType::TopLevel &&
+       mWindowType != WindowType::Dialog))
+    return;
+
+  BOOL isVisible = [mWindow isVisible];
+
+  // Remove child windows.
+  NSArray* childWindows = [mWindow childWindows];
+  NSEnumerator* enumerator = [childWindows objectEnumerator];
+  NSWindow* child = nil;
+  while ((child = [enumerator nextObject])) {
+    [mWindow removeChildWindow:child];
+  }
+
+  // Remove the views in the old window's content view.
+  // The NSArray is autoreleased and retains its NSViews.
+  NSArray<NSView*>* contentViewContents = [mWindow contentViewContents];
+  for (NSView* view in contentViewContents) {
+    [view removeFromSuperviewWithoutNeedingDisplay];
+  }
+
+  // Save state (like window title).
+  NSMutableDictionary* state = [mWindow exportState];
+
+  // Recreate the window with the right border style.
+  NSRect frameRect = [mWindow frame];
+  DestroyNativeWindow();
+  nsresult rv = CreateNativeWindow(
+      frameRect, aShouldHide ? BorderStyle::None : mBorderStyle, true,
+      mWindow.restorable);
+  NS_ENSURE_SUCCESS_VOID(rv);
+
+  // Re-import state.
+  [mWindow importState:state];
+
+  // Add the old content view subviews to the new window's content view.
+  for (NSView* view in contentViewContents) {
+    [[mWindow contentView] addSubview:view];
+  }
+
+  // Reparent child windows.
+  enumerator = [childWindows objectEnumerator];
+  while ((child = [enumerator nextObject])) {
+    [mWindow addChildWindow:child ordered:NSWindowAbove];
+  }
+
+  // Show the new window.
+  if (isVisible) {
+    bool wasAnimationSuppressed = mIsAnimationSuppressed;
+    mIsAnimationSuppressed = true;
+    Show(true);
+    mIsAnimationSuppressed = wasAnimationSuppressed;
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+class FullscreenTransitionData : public nsISupports {
+ public:
+  NS_DECL_ISUPPORTS
+
+  explicit FullscreenTransitionData(NSWindow* aWindow)
+      : mTransitionWindow(aWindow) {}
+
+  NSWindow* mTransitionWindow;
+
+ private:
+  virtual ~FullscreenTransitionData() { [mTransitionWindow close]; }
+};
+
+NS_IMPL_ISUPPORTS0(FullscreenTransitionData)
+
+@interface FullscreenTransitionDelegate : NSObject <NSAnimationDelegate> {
+ @public
+  nsCocoaWindow* mWindow;
+  nsIRunnable* mCallback;
+}
+@end
+
+@implementation FullscreenTransitionDelegate
+- (void)cleanupAndDispatch:(NSAnimation*)animation {
+  [animation setDelegate:nil];
+  [self autorelease];
+  // The caller should have added ref for us.
+  NS_DispatchToMainThread(already_AddRefed<nsIRunnable>(mCallback));
+}
+
+- (void)animationDidEnd:(NSAnimation*)animation {
+  MOZ_ASSERT(animation == mWindow->FullscreenTransitionAnimation(),
+             "Should be handling the only animation on the window");
+  mWindow->ReleaseFullscreenTransitionAnimation();
+  [self cleanupAndDispatch:animation];
+}
+
+- (void)animationDidStop:(NSAnimation*)animation {
+  [self cleanupAndDispatch:animation];
+}
+@end
+
+static bool AlwaysUsesNativeFullScreen() {
+  return Preferences::GetBool("full-screen-api.macos-native-full-screen",
+                              false);
+}
+
+/* virtual */ bool nsCocoaWindow::PrepareForFullscreenTransition(
+    nsISupports** aData) {
+  if (AlwaysUsesNativeFullScreen()) {
+    return false;
+  }
+
+  // Our fullscreen transition creates a new window occluding this window.
+  // That triggers an occlusion event which can cause DOM fullscreen requests
+  // to fail due to the context not being focused at the time the focus check
+  // is performed in the child process. Until the transition is cleaned up in
+  // CleanupFullscreenTransition(), ignore occlusion events for this window.
+  // If this method is changed to return false, the transition will not be
+  // performed and mIgnoreOcclusionCount should not be incremented.
+  MOZ_ASSERT(mIgnoreOcclusionCount >= 0);
+  mIgnoreOcclusionCount++;
+
+  nsCOMPtr<nsIScreen> widgetScreen = GetWidgetScreen();
+  NSScreen* cocoaScreen = ScreenHelperCocoa::CocoaScreenForScreen(widgetScreen);
+
+  NSWindow* win =
+      [[NSWindow alloc] initWithContentRect:[cocoaScreen frame]
+                                  styleMask:NSWindowStyleMaskBorderless
+                                    backing:NSBackingStoreBuffered
+                                      defer:YES];
+  [win setBackgroundColor:[NSColor blackColor]];
+  [win setAlphaValue:0];
+  [win setIgnoresMouseEvents:YES];
+  [win setLevel:NSScreenSaverWindowLevel];
+  [win makeKeyAndOrderFront:nil];
+
+  auto data = new FullscreenTransitionData(win);
+  *aData = data;
+  NS_ADDREF(data);
+  return true;
+}
+
+/* virtual */ void nsCocoaWindow::CleanupFullscreenTransition() {
+  MOZ_ASSERT(mIgnoreOcclusionCount > 0);
+  mIgnoreOcclusionCount--;
+}
+
+/* virtual */ void nsCocoaWindow::PerformFullscreenTransition(
+    FullscreenTransitionStage aStage, uint16_t aDuration, nsISupports* aData,
+    nsIRunnable* aCallback) {
+  auto data = static_cast<FullscreenTransitionData*>(aData);
+  FullscreenTransitionDelegate* delegate =
+      [[FullscreenTransitionDelegate alloc] init];
+  delegate->mWindow = this;
+  // Storing already_AddRefed directly could cause static checking fail.
+  delegate->mCallback = nsCOMPtr<nsIRunnable>(aCallback).forget().take();
+
+  if (mFullscreenTransitionAnimation) {
+    [mFullscreenTransitionAnimation stopAnimation];
+    ReleaseFullscreenTransitionAnimation();
+  }
+
+  NSDictionary* dict = @{
+    NSViewAnimationTargetKey : data->mTransitionWindow,
+    NSViewAnimationEffectKey : aStage == eBeforeFullscreenToggle
+        ? NSViewAnimationFadeInEffect
+        : NSViewAnimationFadeOutEffect
+  };
+  mFullscreenTransitionAnimation =
+      [[NSViewAnimation alloc] initWithViewAnimations:@[ dict ]];
+  [mFullscreenTransitionAnimation setDelegate:delegate];
+  [mFullscreenTransitionAnimation setDuration:aDuration / 1000.0];
+  [mFullscreenTransitionAnimation startAnimation];
+}
+
+void nsCocoaWindow::CocoaWindowWillEnterFullscreen(bool aFullscreen) {
+  MOZ_ASSERT(mUpdateFullscreenOnResize.isNothing());
+
+  mHasStartedNativeFullscreen = true;
+
+  // Ensure that we update our fullscreen state as early as possible, when the
+  // resize happens.
+  mUpdateFullscreenOnResize =
+      Some(aFullscreen ? TransitionType::Fullscreen : TransitionType::Windowed);
+}
+
+void nsCocoaWindow::CocoaWindowDidEnterFullscreen(bool aFullscreen) {
+  EndOurNativeTransition();
+  mHasStartedNativeFullscreen = false;
+  DispatchOcclusionEvent();
+
+  // Check if aFullscreen matches our expected fullscreen state. It might not if
+  // there was a failure somewhere along the way, in which case we'll recover
+  // from that.
+  bool receivedExpectedFullscreen = false;
+  if (mUpdateFullscreenOnResize.isSome()) {
+    bool expectingFullscreen =
+        (*mUpdateFullscreenOnResize == TransitionType::Fullscreen);
+    receivedExpectedFullscreen = (expectingFullscreen == aFullscreen);
+  } else {
+    receivedExpectedFullscreen = (mInFullScreenMode == aFullscreen);
+  }
+
+  TransitionType transition =
+      aFullscreen ? TransitionType::Fullscreen : TransitionType::Windowed;
+  if (receivedExpectedFullscreen) {
+    // Everything is as expected. Update our state if needed.
+    HandleUpdateFullscreenOnResize();
+  } else {
+    // We weren't expecting this fullscreen state. Update our fullscreen state
+    // to the new reality.
+    UpdateFullscreenState(aFullscreen, true);
+
+    // If we have a current transition, switch it to match what we just did.
+    if (mTransitionCurrent.isSome()) {
+      mTransitionCurrent = Some(transition);
+    }
+  }
+
+  // Whether we expected this transition or not, we're ready to finish it.
+  FinishCurrentTransitionIfMatching(transition);
+}
+
+void nsCocoaWindow::UpdateFullscreenState(bool aFullScreen, bool aNativeMode) {
+  bool wasInFullscreen = mInFullScreenMode;
+  mInFullScreenMode = aFullScreen;
+  if (aNativeMode || mInNativeFullScreenMode) {
+    mInNativeFullScreenMode = aFullScreen;
+  }
+
+  if (aFullScreen == wasInFullscreen) {
+    return;
+  }
+
+  DispatchSizeModeEvent();
+
+  // Notify the mainChildView with our new fullscreen state.
+  nsChildView* mainChildView =
+      static_cast<nsChildView*>([[mWindow mainChildView] widget]);
+  if (mainChildView) {
+    mainChildView->UpdateFullscreen(aFullScreen);
+  }
+}
+
+nsresult nsCocoaWindow::MakeFullScreen(bool aFullScreen) {
+  return DoMakeFullScreen(aFullScreen, AlwaysUsesNativeFullScreen());
+}
+
+nsresult nsCocoaWindow::MakeFullScreenWithNativeTransition(bool aFullScreen) {
+  return DoMakeFullScreen(aFullScreen, true);
+}
+
+nsresult nsCocoaWindow::DoMakeFullScreen(bool aFullScreen,
+                                         bool aUseSystemTransition) {
+  if (!mWindow) {
+    return NS_OK;
+  }
+
+  // Figure out what type of transition is being requested.
+  TransitionType transition = TransitionType::Windowed;
+  if (aFullScreen) {
+    // Decide whether to use fullscreen or emulated fullscreen.
+    transition =
+        (aUseSystemTransition && (mWindow.collectionBehavior &
+                                  NSWindowCollectionBehaviorFullScreenPrimary))
+            ? TransitionType::Fullscreen
+            : TransitionType::EmulatedFullscreen;
+  }
+
+  QueueTransition(transition);
+  return NS_OK;
+}
+
+void nsCocoaWindow::QueueTransition(const TransitionType& aTransition) {
+  mTransitionsPending.push(aTransition);
+  ProcessTransitions();
+}
+
+void nsCocoaWindow::ProcessTransitions() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK
+
+  if (mInProcessTransitions) {
+    return;
+  }
+
+  mInProcessTransitions = true;
+
+  // Start a loop that will continue as long as we have transitions to process
+  // and we aren't waiting on an asynchronous transition to complete. Any
+  // transition that starts something async will `continue` this loop to exit.
+  while (!mTransitionsPending.empty() && !IsInTransition()) {
+    TransitionType nextTransition = mTransitionsPending.front();
+
+    // We have to check for some incompatible transition states, and if we find
+    // one, instead perform an alternative transition and leave the queue
+    // untouched. If we add one of these transitions, we set
+    // mIsTransitionCurrentAdded because we don't want to confuse listeners who
+    // are expecting to receive exactly one event when the requested transition
+    // has completed.
+    switch (nextTransition) {
+      case TransitionType::Fullscreen:
+      case TransitionType::EmulatedFullscreen:
+      case TransitionType::Windowed:
+      case TransitionType::Zoom:
+        // These can't handle miniaturized windows, so deminiaturize first.
+        if (mWindow.miniaturized) {
+          mTransitionCurrent = Some(TransitionType::Deminiaturize);
+          mIsTransitionCurrentAdded = true;
+        }
+        break;
+      case TransitionType::Miniaturize:
+        // This can't handle fullscreen, so go to windowed first.
+        if (mInFullScreenMode) {
+          mTransitionCurrent = Some(TransitionType::Windowed);
+          mIsTransitionCurrentAdded = true;
+        }
+        break;
+      default:
+        break;
+    }
+
+    // If mTransitionCurrent is still empty, then we use the nextTransition and
+    // pop the queue.
+    if (mTransitionCurrent.isNothing()) {
+      mTransitionCurrent = Some(nextTransition);
+      mTransitionsPending.pop();
+    }
+
+    switch (*mTransitionCurrent) {
+      case TransitionType::Fullscreen: {
+        if (!mInFullScreenMode) {
+          // Run a local run loop until it is safe to start a native fullscreen
+          // transition.
+          NSRunLoop* localRunLoop = [NSRunLoop currentRunLoop];
+          while (mWindow && !CanStartNativeTransition() &&
+                 [localRunLoop runMode:NSDefaultRunLoopMode
+                            beforeDate:[NSDate distantFuture]]) {
+            // This loop continues to process events until
+            // CanStartNativeTransition() returns true or our native
+            // window has been destroyed.
+          }
+
+          // This triggers an async animation, so continue.
+          [mWindow toggleFullScreen:nil];
+          continue;
+        }
+        break;
+      }
+
+      case TransitionType::EmulatedFullscreen: {
+        if (!mInFullScreenMode) {
+          NSDisableScreenUpdates();
+          mSuppressSizeModeEvents = true;
+          // The order here matters. When we exit full screen mode, we need to
+          // show the Dock first, otherwise the newly-created window won't have
+          // its minimize button enabled. See bug 526282.
+          nsCocoaUtils::HideOSChromeOnScreen(true);
+          nsBaseWidget::InfallibleMakeFullScreen(true);
+          mSuppressSizeModeEvents = false;
+          NSEnableScreenUpdates();
+          UpdateFullscreenState(true, false);
+        }
+        break;
+      }
+
+      case TransitionType::Windowed: {
+        if (mInFullScreenMode) {
+          if (mInNativeFullScreenMode) {
+            // Run a local run loop until it is safe to start a native
+            // fullscreen transition.
+            NSRunLoop* localRunLoop = [NSRunLoop currentRunLoop];
+            while (mWindow && !CanStartNativeTransition() &&
+                   [localRunLoop runMode:NSDefaultRunLoopMode
+                              beforeDate:[NSDate distantFuture]]) {
+              // This loop continues to process events until
+              // CanStartNativeTransition() returns true or our native
+              // window has been destroyed.
+            }
+
+            // This triggers an async animation, so continue.
+            [mWindow toggleFullScreen:nil];
+            continue;
+          } else {
+            NSDisableScreenUpdates();
+            mSuppressSizeModeEvents = true;
+            // The order here matters. When we exit full screen mode, we need to
+            // show the Dock first, otherwise the newly-created window won't
+            // have its minimize button enabled. See bug 526282.
+            nsCocoaUtils::HideOSChromeOnScreen(false);
+            nsBaseWidget::InfallibleMakeFullScreen(false);
+            mSuppressSizeModeEvents = false;
+            NSEnableScreenUpdates();
+            UpdateFullscreenState(false, false);
+          }
+        } else if (mWindow.zoomed) {
+          [mWindow zoom:nil];
+
+          // Check if we're still zoomed. If we are, we need to do *something*
+          // to make the window smaller than the zoom size so Cocoa will treat
+          // us as being out of the zoomed state. Otherwise, we could stay
+          // zoomed and never be able to be "normal" from calls to SetSizeMode.
+          if (mWindow.zoomed) {
+            NSRect maximumFrame = mWindow.frame;
+            const CGFloat INSET_OUT_OF_ZOOM = 20.0f;
+            [mWindow setFrame:NSInsetRect(maximumFrame, INSET_OUT_OF_ZOOM,
+                                          INSET_OUT_OF_ZOOM)
+                      display:YES];
+            MOZ_ASSERT(
+                !mWindow.zoomed,
+                "We should be able to unzoom by shrinking the frame a bit.");
+          }
+        }
+        break;
+      }
+
+      case TransitionType::Miniaturize:
+        if (!mWindow.miniaturized) {
+          // This triggers an async animation, so continue.
+          [mWindow miniaturize:nil];
+          continue;
+        }
+        break;
+
+      case TransitionType::Deminiaturize:
+        if (mWindow.miniaturized) {
+          // This triggers an async animation, so continue.
+          [mWindow deminiaturize:nil];
+          continue;
+        }
+        break;
+
+      case TransitionType::Zoom:
+        if (!mWindow.zoomed) {
+          [mWindow zoom:nil];
+        }
+        break;
+
+      default:
+        break;
+    }
+
+    mTransitionCurrent.reset();
+    mIsTransitionCurrentAdded = false;
+  }
+
+  mInProcessTransitions = false;
+
+  // When we finish processing transitions, dispatch a size mode event to cover
+  // the cases where an inserted transition suppressed one, and the original
+  // transition never sent one because it detected it was at the desired state
+  // when it ran. If we've already sent a size mode event, then this will be a
+  // no-op.
+  if (!IsInTransition()) {
+    DispatchSizeModeEvent();
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::CancelAllTransitions() {
+  // Clear our current and pending transitions. This simplifies our
+  // reasoning about what happens next, and ensures that whatever is
+  // currently happening won't trigger another call to
+  // ProcessTransitions().
+  mTransitionCurrent.reset();
+  mIsTransitionCurrentAdded = false;
+  std::queue<TransitionType>().swap(mTransitionsPending);
+}
+
+void nsCocoaWindow::FinishCurrentTransitionIfMatching(
+    const TransitionType& aTransition) {
+  // We've just finished some transition activity, and we're not sure whether it
+  // was triggered programmatically, or by the user. If it matches our current
+  // transition, then assume it was triggered programmatically and we can clean
+  // up that transition and start processing transitions again.
+
+  // Whether programmatic or user-initiated, we send out a size mode event.
+  DispatchSizeModeEvent();
+
+  if (mTransitionCurrent.isSome() && (*mTransitionCurrent == aTransition)) {
+    // This matches our current transition, so do the safe parts of transition
+    // cleanup.
+    mTransitionCurrent.reset();
+    mIsTransitionCurrentAdded = false;
+
+    // Since this function is called from nsWindowDelegate transition callbacks,
+    // we want to make sure those callbacks are all the way done before we
+    // continue processing more transitions. To accomplish this, we dispatch
+    // ProcessTransitions on the next event loop. Doing this will ensure that
+    // any async native transition methods we call (like toggleFullScreen) will
+    // succeed.
+    if (!mTransitionsPending.empty()) {
+      NS_DispatchToCurrentThread(NewRunnableMethod(
+          "FinishCurrentTransition", this, &nsCocoaWindow::ProcessTransitions));
+    }
+  }
+}
+
+bool nsCocoaWindow::HandleUpdateFullscreenOnResize() {
+  if (mUpdateFullscreenOnResize.isNothing()) {
+    return false;
+  }
+
+  bool toFullscreen =
+      (*mUpdateFullscreenOnResize == TransitionType::Fullscreen);
+  mUpdateFullscreenOnResize.reset();
+  UpdateFullscreenState(toFullscreen, true);
+
+  return true;
+}
+
+/* static */ nsCocoaWindow* nsCocoaWindow::sWindowInNativeTransition(nullptr);
+
+bool nsCocoaWindow::CanStartNativeTransition() {
+  if (sWindowInNativeTransition == nullptr) {
+    // Claim it and return true, indicating that the caller has permission to
+    // start the native fullscreen transition.
+    sWindowInNativeTransition = this;
+    return true;
+  }
+  return false;
+}
+
+void nsCocoaWindow::EndOurNativeTransition() {
+  if (sWindowInNativeTransition == this) {
+    sWindowInNativeTransition = nullptr;
+  }
+}
+
+// Coordinates are desktop pixels
+void nsCocoaWindow::DoResize(double aX, double aY, double aWidth,
+                             double aHeight, bool aRepaint,
+                             bool aConstrainToCurrentScreen) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mWindow || mInResize) {
+    return;
+  }
+
+  // We are able to resize a window outside of any aspect ratio contraints
+  // applied to it, but in order to "update" the aspect ratio contraint to the
+  // new window dimensions, we must re-lock the aspect ratio.
+  auto relockAspectRatio = MakeScopeExit([&]() {
+    if (mAspectRatioLocked) {
+      LockAspectRatio(true);
+    }
+  });
+
+  AutoRestore<bool> reentrantResizeGuard(mInResize);
+  mInResize = true;
+
+  CGFloat scale = mSizeConstraints.mScale.scale;
+  if (scale == MOZ_WIDGET_INVALID_SCALE) {
+    scale = BackingScaleFactor();
+  }
+
+  // mSizeConstraints is in device pixels.
+  int32_t width = NSToIntRound(aWidth * scale);
+  int32_t height = NSToIntRound(aHeight * scale);
+
+  width = std::max(mSizeConstraints.mMinSize.width,
+                   std::min(mSizeConstraints.mMaxSize.width, width));
+  height = std::max(mSizeConstraints.mMinSize.height,
+                    std::min(mSizeConstraints.mMaxSize.height, height));
+
+  DesktopIntRect newBounds(NSToIntRound(aX), NSToIntRound(aY),
+                           NSToIntRound(width / scale),
+                           NSToIntRound(height / scale));
+
+  // convert requested bounds into Cocoa coordinate system
+  NSRect newFrame = nsCocoaUtils::GeckoRectToCocoaRect(newBounds);
+
+  NSRect frame = [mWindow frame];
+  BOOL isMoving = newFrame.origin.x != frame.origin.x ||
+                  newFrame.origin.y != frame.origin.y;
+  BOOL isResizing = newFrame.size.width != frame.size.width ||
+                    newFrame.size.height != frame.size.height;
+
+  if (!isMoving && !isResizing) {
+    return;
+  }
+
+  // We ignore aRepaint -- we have to call display:YES, otherwise the
+  // title bar doesn't immediately get repainted and is displayed in
+  // the wrong place, leading to a visual jump.
+  [mWindow setFrame:newFrame display:YES];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Coordinates are desktop pixels
+void nsCocoaWindow::Resize(double aX, double aY, double aWidth, double aHeight,
+                           bool aRepaint) {
+  DoResize(aX, aY, aWidth, aHeight, aRepaint, false);
+}
+
+// Coordinates are desktop pixels
+void nsCocoaWindow::Resize(double aWidth, double aHeight, bool aRepaint) {
+  double invScale = 1.0 / BackingScaleFactor();
+  DoResize(mBounds.x * invScale, mBounds.y * invScale, aWidth, aHeight,
+           aRepaint, true);
+}
+
+// Return the area that the Gecko ChildView in our window should cover, as an
+// NSRect in screen coordinates (with 0,0 being the bottom left corner of the
+// primary screen).
+NSRect nsCocoaWindow::GetClientCocoaRect() {
+  if (!mWindow) {
+    return NSZeroRect;
+  }
+
+  return [mWindow childViewRectForFrameRect:[mWindow frame]];
+}
+
+LayoutDeviceIntRect nsCocoaWindow::GetClientBounds() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  CGFloat scaleFactor = BackingScaleFactor();
+  return nsCocoaUtils::CocoaRectToGeckoRectDevPix(GetClientCocoaRect(),
+                                                  scaleFactor);
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(LayoutDeviceIntRect(0, 0, 0, 0));
+}
+
+void nsCocoaWindow::UpdateBounds() {
+  NSRect frame = NSZeroRect;
+  if (mWindow) {
+    frame = [mWindow frame];
+  }
+  mBounds =
+      nsCocoaUtils::CocoaRectToGeckoRectDevPix(frame, BackingScaleFactor());
+
+  if (mPopupContentView) {
+    mPopupContentView->UpdateBoundsFromView();
+  }
+}
+
+LayoutDeviceIntRect nsCocoaWindow::GetScreenBounds() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+#ifdef DEBUG
+  LayoutDeviceIntRect r = nsCocoaUtils::CocoaRectToGeckoRectDevPix(
+      [mWindow frame], BackingScaleFactor());
+  NS_ASSERTION(mWindow && mBounds == r, "mBounds out of sync!");
+#endif
+
+  return mBounds;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(LayoutDeviceIntRect(0, 0, 0, 0));
+}
+
+double nsCocoaWindow::GetDefaultScaleInternal() { return BackingScaleFactor(); }
+
+static CGFloat GetBackingScaleFactor(NSWindow* aWindow) {
+  NSRect frame = [aWindow frame];
+  if (frame.size.width > 0 && frame.size.height > 0) {
+    return nsCocoaUtils::GetBackingScaleFactor(aWindow);
+  }
+
+  // For windows with zero width or height, the backingScaleFactor method
+  // is broken - it will always return 2 on a retina macbook, even when
+  // the window position implies it's on a non-hidpi external display
+  // (to the extent that a zero-area window can be said to be "on" a
+  // display at all!)
+  // And to make matters worse, Cocoa even fires a
+  // windowDidChangeBackingProperties notification with the
+  // NSBackingPropertyOldScaleFactorKey key when a window on an
+  // external display is resized to/from zero height, even though it hasn't
+  // really changed screens.
+
+  // This causes us to handle popup window sizing incorrectly when the
+  // popup is resized to zero height (bug 820327) - nsXULPopupManager
+  // becomes (incorrectly) convinced the popup has been explicitly forced
+  // to a non-default size and needs to have size attributes attached.
+
+  // Workaround: instead of asking the window, we'll find the screen it is on
+  // and ask that for *its* backing scale factor.
+
+  // (See bug 853252 and additional comments in windowDidChangeScreen: below
+  // for further complications this causes.)
+
+  // First, expand the rect so that it actually has a measurable area,
+  // for FindTargetScreenForRect to use.
+  if (frame.size.width == 0) {
+    frame.size.width = 1;
+  }
+  if (frame.size.height == 0) {
+    frame.size.height = 1;
+  }
+
+  // Then identify the screen it belongs to, and return its scale factor.
+  NSScreen* screen =
+      FindTargetScreenForRect(nsCocoaUtils::CocoaRectToGeckoRect(frame));
+  return nsCocoaUtils::GetBackingScaleFactor(screen);
+}
+
+CGFloat nsCocoaWindow::BackingScaleFactor() {
+  if (mBackingScaleFactor > 0.0) {
+    return mBackingScaleFactor;
+  }
+  if (!mWindow) {
+    return 1.0;
+  }
+  mBackingScaleFactor = GetBackingScaleFactor(mWindow);
+  return mBackingScaleFactor;
+}
+
+void nsCocoaWindow::BackingScaleFactorChanged() {
+  CGFloat newScale = GetBackingScaleFactor(mWindow);
+
+  // ignore notification if it hasn't really changed (or maybe we have
+  // disabled HiDPI mode via prefs)
+  if (mBackingScaleFactor == newScale) {
+    return;
+  }
+
+  mBackingScaleFactor = newScale;
+
+  if (!mWidgetListener || mWidgetListener->GetAppWindow()) {
+    return;
+  }
+
+  if (PresShell* presShell = mWidgetListener->GetPresShell()) {
+    presShell->BackingScaleFactorChanged();
+  }
+  mWidgetListener->UIResolutionChanged();
+}
+
+int32_t nsCocoaWindow::RoundsWidgetCoordinatesTo() {
+  if (BackingScaleFactor() == 2.0) {
+    return 2;
+  }
+  return 1;
+}
+
+void nsCocoaWindow::SetCursor(const Cursor& aCursor) {
+  if (mPopupContentView) {
+    mPopupContentView->SetCursor(aCursor);
+  }
+}
+
+nsresult nsCocoaWindow::SetTitle(const nsAString& aTitle) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!mWindow) {
+    return NS_OK;
+  }
+
+  const nsString& strTitle = PromiseFlatString(aTitle);
+  const unichar* uniTitle = reinterpret_cast<const unichar*>(strTitle.get());
+  NSString* title = [NSString stringWithCharacters:uniTitle
+                                            length:strTitle.Length()];
+  if ([mWindow drawsContentsIntoWindowFrame] && ![mWindow wantsTitleDrawn]) {
+    // Don't cause invalidations when the title isn't displayed.
+    [mWindow disableSetNeedsDisplay];
+    [mWindow setTitle:title];
+    [mWindow enableSetNeedsDisplay];
+  } else {
+    [mWindow setTitle:title];
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void nsCocoaWindow::Invalidate(const LayoutDeviceIntRect& aRect) {
+  if (mPopupContentView) {
+    mPopupContentView->Invalidate(aRect);
+  }
+}
+
+// Pass notification of some drag event to Gecko
+//
+// The drag manager has let us know that something related to a drag has
+// occurred in this window. It could be any number of things, ranging from
+// a drop, to a drag enter/leave, or a drag over event. The actual event
+// is passed in |aMessage| and is passed along to our event hanlder so Gecko
+// knows about it.
+bool nsCocoaWindow::DragEvent(unsigned int aMessage,
+                              mozilla::gfx::Point aMouseGlobal,
+                              UInt16 aKeyModifiers) {
+  return false;
+}
+
+NS_IMETHODIMP nsCocoaWindow::SendSetZLevelEvent() {
+  nsWindowZ placement = nsWindowZTop;
+  nsCOMPtr<nsIWidget> actualBelow;
+  if (mWidgetListener)
+    mWidgetListener->ZLevelChanged(true, &placement, nullptr,
+                                   getter_AddRefs(actualBelow));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsCocoaWindow::GetChildSheet(bool aShown, nsIWidget** _retval) {
+  nsIWidget* child = GetFirstChild();
+
+  while (child) {
+    if (child->GetWindowType() == WindowType::Sheet) {
+      // if it's a sheet, it must be an nsCocoaWindow
+      nsCocoaWindow* cocoaWindow = static_cast<nsCocoaWindow*>(child);
+      if (cocoaWindow->mWindow &&
+          ((aShown && [cocoaWindow->mWindow isVisible]) ||
+           (!aShown && cocoaWindow->mSheetNeedsShow))) {
+        nsCOMPtr<nsIWidget> widget = cocoaWindow;
+        widget.forget(_retval);
+        return NS_OK;
+      }
+    }
+    child = child->GetNextSibling();
+  }
+
+  *_retval = nullptr;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsCocoaWindow::GetRealParent(nsIWidget** parent) {
+  *parent = mParent;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsCocoaWindow::GetIsSheet(bool* isSheet) {
+  mWindowType == WindowType::Sheet ? * isSheet = true : * isSheet = false;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsCocoaWindow::GetSheetWindowParent(
+    NSWindow** sheetWindowParent) {
+  *sheetWindowParent = mSheetWindowParent;
+  return NS_OK;
+}
+
+// Invokes callback and ProcessEvent methods on Event Listener object
+nsresult nsCocoaWindow::DispatchEvent(WidgetGUIEvent* event,
+                                      nsEventStatus& aStatus) {
+  aStatus = nsEventStatus_eIgnore;
+
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(event->mWidget);
+  mozilla::Unused << kungFuDeathGrip;  // Not used within this function
+
+  if (mWidgetListener)
+    aStatus = mWidgetListener->HandleEvent(event, mUseAttachedEvents);
+
+  return NS_OK;
+}
+
+// aFullScreen should be the window's mInFullScreenMode. We don't have access to
+// that from here, so we need to pass it in. mInFullScreenMode should be the
+// canonical indicator that a window is currently full screen and it makes sense
+// to keep all sizemode logic here.
+static nsSizeMode GetWindowSizeMode(NSWindow* aWindow, bool aFullScreen) {
+  if (aFullScreen) return nsSizeMode_Fullscreen;
+  if ([aWindow isMiniaturized]) return nsSizeMode_Minimized;
+  if (([aWindow styleMask] & NSWindowStyleMaskResizable) && [aWindow isZoomed])
+    return nsSizeMode_Maximized;
+  return nsSizeMode_Normal;
+}
+
+void nsCocoaWindow::ReportMoveEvent() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Prevent recursion, which can become infinite (see bug 708278).  This
+  // can happen when the call to [NSWindow setFrameTopLeftPoint:] in
+  // nsCocoaWindow::Move() triggers an immediate NSWindowDidMove notification
+  // (and a call to [WindowDelegate windowDidMove:]).
+  if (mInReportMoveEvent) {
+    return;
+  }
+  mInReportMoveEvent = true;
+
+  UpdateBounds();
+
+  // The zoomed state can change when we're moving, in which case we need to
+  // update our internal mSizeMode. This can happen either if we're maximized
+  // and then moved, or if we're not maximized and moved back to zoomed state.
+  if (mWindow && ((mSizeMode == nsSizeMode_Maximized) ^ [mWindow isZoomed])) {
+    DispatchSizeModeEvent();
+  }
+
+  // Dispatch the move event to Gecko
+  NotifyWindowMoved(mBounds.x, mBounds.y);
+
+  mInReportMoveEvent = false;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::DispatchSizeModeEvent() {
+  if (!mWindow) {
+    return;
+  }
+
+  if (mSuppressSizeModeEvents || mIsTransitionCurrentAdded) {
+    return;
+  }
+
+  nsSizeMode newMode = GetWindowSizeMode(mWindow, mInFullScreenMode);
+  if (mSizeMode == newMode) {
+    return;
+  }
+
+  mSizeMode = newMode;
+  if (mWidgetListener) {
+    mWidgetListener->SizeModeChanged(newMode);
+  }
+}
+
+void nsCocoaWindow::DispatchOcclusionEvent() {
+  if (!mWindow) {
+    return;
+  }
+
+  // Our new occlusion state is true if the window is not visible.
+  bool newOcclusionState =
+      !(mHasStartedNativeFullscreen ||
+        ([mWindow occlusionState] & NSWindowOcclusionStateVisible));
+
+  // Don't dispatch if the new occlustion state is the same as the current
+  // state.
+  if (mIsFullyOccluded == newOcclusionState) {
+    return;
+  }
+
+  MOZ_ASSERT(mIgnoreOcclusionCount >= 0);
+  if (newOcclusionState && mIgnoreOcclusionCount > 0) {
+    return;
+  }
+
+  mIsFullyOccluded = newOcclusionState;
+  if (mWidgetListener) {
+    mWidgetListener->OcclusionStateChanged(mIsFullyOccluded);
+  }
+}
+
+void nsCocoaWindow::ReportSizeEvent() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  UpdateBounds();
+  if (mWidgetListener) {
+    LayoutDeviceIntRect innerBounds = GetClientBounds();
+    mWidgetListener->WindowResized(this, innerBounds.width, innerBounds.height);
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::SetMenuBar(RefPtr<nsMenuBarX>&& aMenuBar) {
+  if (!mWindow) {
+    mMenuBar = nullptr;
+    return;
+  }
+  mMenuBar = std::move(aMenuBar);
+
+  // Only paint for active windows, or paint the hidden window menu bar if no
+  // other menu bar has been painted yet so that some reasonable menu bar is
+  // displayed when the app starts up.
+  if (mMenuBar && ((!gSomeMenuBarPainted &&
+                    nsMenuUtilsX::GetHiddenWindowMenuBar() == mMenuBar) ||
+                   [mWindow isMainWindow]))
+    mMenuBar->Paint();
+}
+
+void nsCocoaWindow::SetFocus(Raise aRaise,
+                             mozilla::dom::CallerType aCallerType) {
+  if (!mWindow) return;
+
+  if (mPopupContentView) {
+    return mPopupContentView->SetFocus(aRaise, aCallerType);
+  }
+
+  if (aRaise == Raise::Yes &&
+      ([mWindow isVisible] || [mWindow isMiniaturized])) {
+    if ([mWindow isMiniaturized]) {
+      [mWindow deminiaturize:nil];
+    }
+
+    [mWindow makeKeyAndOrderFront:nil];
+    SendSetZLevelEvent();
+  }
+}
+
+LayoutDeviceIntPoint nsCocoaWindow::WidgetToScreenOffset() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return nsCocoaUtils::CocoaRectToGeckoRectDevPix(GetClientCocoaRect(),
+                                                  BackingScaleFactor())
+      .TopLeft();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(LayoutDeviceIntPoint(0, 0));
+}
+
+LayoutDeviceIntPoint nsCocoaWindow::GetClientOffset() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  LayoutDeviceIntRect clientRect = GetClientBounds();
+
+  return clientRect.TopLeft() - mBounds.TopLeft();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(LayoutDeviceIntPoint(0, 0));
+}
+
+LayoutDeviceIntMargin nsCocoaWindow::ClientToWindowMargin() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!mWindow || mWindow.drawsContentsIntoWindowFrame ||
+      mWindowType == WindowType::Popup) {
+    return {};
+  }
+
+  NSRect clientNSRect = mWindow.contentLayoutRect;
+  NSRect frameNSRect = [mWindow frameRectForChildViewRect:clientNSRect];
+
+  CGFloat backingScale = BackingScaleFactor();
+  const auto clientRect =
+      nsCocoaUtils::CocoaRectToGeckoRectDevPix(clientNSRect, backingScale);
+  const auto frameRect =
+      nsCocoaUtils::CocoaRectToGeckoRectDevPix(frameNSRect, backingScale);
+
+  return frameRect - clientRect;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN({});
+}
+
+nsMenuBarX* nsCocoaWindow::GetMenuBar() { return mMenuBar; }
+
+void nsCocoaWindow::CaptureRollupEvents(bool aDoCapture) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (aDoCapture) {
+    if (![NSApp isActive]) {
+      // We need to capture mouse event if we aren't
+      // the active application. We only set this up when needed
+      // because they cause spurious mouse event after crash
+      // and gdb sessions. See bug 699538.
+      nsToolkit::GetToolkit()->MonitorAllProcessMouseEvents();
+    }
+
+    // Sometimes more than one popup window can be visible at the same time
+    // (e.g. nested non-native context menus, or the test case (attachment
+    // 276885) for bmo bug 392389, which displays a non-native combo-box in a
+    // non-native popup window).  In these cases the "active" popup window
+    // should be the topmost -- the (nested) context menu the mouse is currently
+    // over, or the combo-box's drop-down list (when it's displayed).  But
+    // (among windows that have the same "level") OS X makes topmost the window
+    // that last received a mouse-down event, which may be incorrect (in the
+    // combo-box case, it makes topmost the window containing the combo-box).
+    // So here we fiddle with a non-native popup window's level to make sure the
+    // "active" one is always above any other non-native popup windows that
+    // may be visible.
+    if (mWindow && (mWindowType == WindowType::Popup)) SetPopupWindowLevel();
+  } else {
+    nsToolkit::GetToolkit()->StopMonitoringAllProcessMouseEvents();
+
+    // XXXndeakin this doesn't make sense.
+    // Why is the new window assumed to be a modal panel?
+    if (mWindow && (mWindowType == WindowType::Popup))
+      [mWindow setLevel:NSModalPanelWindowLevel];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+nsresult nsCocoaWindow::GetAttention(int32_t aCycleCount) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  [NSApp requestUserAttention:NSInformationalRequest];
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+bool nsCocoaWindow::HasPendingInputEvent() {
+  return nsChildView::DoHasPendingInputEvent();
+}
+
+void nsCocoaWindow::SetWindowShadowStyle(WindowShadow aStyle) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mShadowStyle == aStyle) {
+    return;
+  }
+
+  mShadowStyle = aStyle;
+
+  if (!mWindow || mWindowType != WindowType::Popup) {
+    return;
+  }
+
+  mWindow.shadowStyle = mShadowStyle;
+  [mWindow setEffectViewWrapperForStyle:mShadowStyle];
+  [mWindow setHasShadow:aStyle != WindowShadow::None];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::SetWindowOpacity(float aOpacity) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mWindow) {
+    return;
+  }
+
+  [mWindow setAlphaValue:(CGFloat)aOpacity];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::SetColorScheme(const Maybe<ColorScheme>& aScheme) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mWindow) {
+    return;
+  }
+
+  mWindow.appearance = aScheme ? NSAppearanceForColorScheme(*aScheme) : nil;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+static inline CGAffineTransform GfxMatrixToCGAffineTransform(
+    const gfx::Matrix& m) {
+  CGAffineTransform t;
+  t.a = m._11;
+  t.b = m._12;
+  t.c = m._21;
+  t.d = m._22;
+  t.tx = m._31;
+  t.ty = m._32;
+  return t;
+}
+
+void nsCocoaWindow::SetWindowTransform(const gfx::Matrix& aTransform) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mWindow) {
+    return;
+  }
+
+  // Calling CGSSetWindowTransform when the window is not visible results in
+  // misplacing the window into doubled x,y coordinates (see bug 1448132).
+  if (![mWindow isVisible] || NSIsEmptyRect([mWindow frame])) {
+    return;
+  }
+
+  if (StaticPrefs::widget_window_transforms_disabled()) {
+    // CGSSetWindowTransform is a private API. In case calling it causes
+    // problems either now or in the future, we'll want to have an easy kill
+    // switch. So we allow disabling it with a pref.
+    return;
+  }
+
+  gfx::Matrix transform = aTransform;
+
+  // aTransform is a transform that should be applied to the window relative
+  // to its regular position: If aTransform._31 is 100, then we want the
+  // window to be displayed 100 pixels to the right of its regular position.
+  // The transform that CGSSetWindowTransform accepts has a different meaning:
+  // It's used to answer the question "For the screen pixel at x,y (with the
+  // origin at the top left), what pixel in the window's buffer (again with
+  // origin top left) should be displayed at that position?"
+  // In the example above, this means that we need to call
+  // CGSSetWindowTransform with a horizontal translation of -windowPos.x - 100.
+  // So we need to invert the transform and adjust it by the window's position.
+  if (!transform.Invert()) {
+    // Treat non-invertible transforms as the identity transform.
+    transform = gfx::Matrix();
+  }
+
+  bool isIdentity = transform.IsIdentity();
+  if (isIdentity && mWindowTransformIsIdentity) {
+    return;
+  }
+
+  transform.PreTranslate(-mBounds.x, -mBounds.y);
+
+  // Snap translations to device pixels, to match what we do for CSS transforms
+  // and because the window server rounds down instead of to nearest.
+  if (!transform.HasNonTranslation() && transform.HasNonIntegerTranslation()) {
+    auto snappedTranslation = gfx::IntPoint::Round(transform.GetTranslation());
+    transform =
+        gfx::Matrix::Translation(snappedTranslation.x, snappedTranslation.y);
+  }
+
+  // We also need to account for the backing scale factor: aTransform is given
+  // in device pixels, but CGSSetWindowTransform works with logical display
+  // pixels.
+  CGFloat backingScale = BackingScaleFactor();
+  transform.PreScale(backingScale, backingScale);
+  transform.PostScale(1 / backingScale, 1 / backingScale);
+
+  CGSConnection cid = _CGSDefaultConnection();
+  CGSSetWindowTransform(cid, [mWindow windowNumber],
+                        GfxMatrixToCGAffineTransform(transform));
+
+  mWindowTransformIsIdentity = isIdentity;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::SetInputRegion(const InputRegion& aInputRegion) {
+  MOZ_ASSERT(mWindowType == WindowType::Popup,
+             "This should only be called on popup windows.");
+  // TODO: Somehow support aInputRegion.mMargin? Though maybe not.
+  if (aInputRegion.mFullyTransparent) {
+    [mWindow setIgnoresMouseEvents:YES];
+  } else {
+    [mWindow setIgnoresMouseEvents:NO];
+  }
+}
+
+void nsCocoaWindow::SetShowsToolbarButton(bool aShow) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mWindow) [mWindow setShowsToolbarButton:aShow];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::SetSupportsNativeFullscreen(
+    bool aSupportsNativeFullscreen) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mWindow) {
+    // This determines whether we tell cocoa that the window supports native
+    // full screen. If we do so, and another window is in native full screen,
+    // this window will also appear in native full screen. We generally only
+    // want to do this for primary application windows. We'll set the
+    // relevant macnativefullscreen attribute on those, which will lead to us
+    // being called with aSupportsNativeFullscreen set to `true` here.
+    NSWindowCollectionBehavior newBehavior = [mWindow collectionBehavior];
+    if (aSupportsNativeFullscreen) {
+      newBehavior |= NSWindowCollectionBehaviorFullScreenPrimary;
+    } else {
+      newBehavior &= ~NSWindowCollectionBehaviorFullScreenPrimary;
+    }
+    [mWindow setCollectionBehavior:newBehavior];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::SetWindowAnimationType(
+    nsIWidget::WindowAnimationType aType) {
+  mAnimationType = aType;
+}
+
+void nsCocoaWindow::SetDrawsTitle(bool aDrawTitle) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (![mWindow drawsContentsIntoWindowFrame]) {
+    // If we don't draw into the window frame, we always want to display window
+    // titles.
+    [mWindow setWantsTitleDrawn:YES];
+  } else {
+    [mWindow setWantsTitleDrawn:aDrawTitle];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+nsresult nsCocoaWindow::SetNonClientMargins(
+    const LayoutDeviceIntMargin& margins) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  SetDrawsInTitlebar(margins.top == 0);
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void nsCocoaWindow::SetDrawsInTitlebar(bool aState) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mWindow) {
+    [mWindow setDrawsContentsIntoWindowFrame:aState];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+NS_IMETHODIMP nsCocoaWindow::SynthesizeNativeMouseEvent(
+    LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+    MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+    nsIObserver* aObserver) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  AutoObserverNotifier notifier(aObserver, "mouseevent");
+  if (mPopupContentView) {
+    return mPopupContentView->SynthesizeNativeMouseEvent(
+        aPoint, aNativeMessage, aButton, aModifierFlags, nullptr);
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP nsCocoaWindow::SynthesizeNativeMouseScrollEvent(
+    LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage, double aDeltaX,
+    double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+    uint32_t aAdditionalFlags, nsIObserver* aObserver) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  AutoObserverNotifier notifier(aObserver, "mousescrollevent");
+  if (mPopupContentView) {
+    // Pass nullptr as the observer so that the AutoObserverNotification in
+    // nsChildView::SynthesizeNativeMouseScrollEvent will be ignored.
+    return mPopupContentView->SynthesizeNativeMouseScrollEvent(
+        aPoint, aNativeMessage, aDeltaX, aDeltaY, aDeltaZ, aModifierFlags,
+        aAdditionalFlags, nullptr);
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void nsCocoaWindow::LockAspectRatio(bool aShouldLock) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (aShouldLock) {
+    [mWindow setContentAspectRatio:mWindow.frame.size];
+    mAspectRatioLocked = true;
+  } else {
+    // According to
+    // https://developer.apple.com/documentation/appkit/nswindow/1419507-aspectratio,
+    // aspect ratios and resize increments are mutually exclusive, and the
+    // accepted way of cancelling an established aspect ratio is to set the
+    // resize increments to 1.0, 1.0
+    [mWindow setResizeIncrements:NSMakeSize(1.0, 1.0)];
+    mAspectRatioLocked = false;
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::UpdateThemeGeometries(
+    const nsTArray<ThemeGeometry>& aThemeGeometries) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mPopupContentView) {
+    return mPopupContentView->UpdateThemeGeometries(aThemeGeometries);
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsCocoaWindow::SetPopupWindowLevel() {
+  if (!mWindow) return;
+
+  // Floating popups are at the floating level and hide when the window is
+  // deactivated.
+  if (mPopupLevel == PopupLevel::Floating) {
+    [mWindow setLevel:NSFloatingWindowLevel];
+    [mWindow setHidesOnDeactivate:YES];
+  } else {
+    // Otherwise, this is a top-level or parent popup. Parent popups always
+    // appear just above their parent and essentially ignore the level.
+    [mWindow setLevel:NSPopUpMenuWindowLevel];
+    [mWindow setHidesOnDeactivate:NO];
+  }
+}
+
+void nsCocoaWindow::SetInputContext(const InputContext& aContext,
+                                    const InputContextAction& aAction) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  mInputContext = aContext;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+bool nsCocoaWindow::GetEditCommands(NativeKeyBindingsType aType,
+                                    const WidgetKeyboardEvent& aEvent,
+                                    nsTArray<CommandInt>& aCommands) {
+  // Validate the arguments.
+  if (NS_WARN_IF(!nsIWidget::GetEditCommands(aType, aEvent, aCommands))) {
+    return false;
+  }
+
+  NativeKeyBindings* keyBindings = NativeKeyBindings::GetInstance(aType);
+  // When the keyboard event is fired from this widget, it must mean that no web
+  // content has focus because any web contents should be on `nsChildView`.  And
+  // in any locales, the system UI is always horizontal layout.  So, let's pass
+  // `Nothing()` for the writing mode here, it won't be treated as in a vertical
+  // content.
+  keyBindings->GetEditCommands(aEvent, Nothing(), aCommands);
+  return true;
+}
+
+void nsCocoaWindow::PauseOrResumeCompositor(bool aPause) {
+  if (auto* mainChildView =
+          static_cast<nsIWidget*>([[mWindow mainChildView] widget])) {
+    mainChildView->PauseOrResumeCompositor(aPause);
+  }
+}
+
+bool nsCocoaWindow::AsyncPanZoomEnabled() const {
+  if (mPopupContentView) {
+    return mPopupContentView->AsyncPanZoomEnabled();
+  }
+  return nsBaseWidget::AsyncPanZoomEnabled();
+}
+
+bool nsCocoaWindow::StartAsyncAutoscroll(const ScreenPoint& aAnchorLocation,
+                                         const ScrollableLayerGuid& aGuid) {
+  if (mPopupContentView) {
+    return mPopupContentView->StartAsyncAutoscroll(aAnchorLocation, aGuid);
+  }
+  return nsBaseWidget::StartAsyncAutoscroll(aAnchorLocation, aGuid);
+}
+
+void nsCocoaWindow::StopAsyncAutoscroll(const ScrollableLayerGuid& aGuid) {
+  if (mPopupContentView) {
+    mPopupContentView->StopAsyncAutoscroll(aGuid);
+    return;
+  }
+  nsBaseWidget::StopAsyncAutoscroll(aGuid);
+}
+
+already_AddRefed<nsIWidget> nsIWidget::CreateTopLevelWindow() {
+  nsCOMPtr<nsIWidget> window = new nsCocoaWindow();
+  return window.forget();
+}
+
+already_AddRefed<nsIWidget> nsIWidget::CreateChildWindow() {
+  nsCOMPtr<nsIWidget> window = new nsChildView();
+  return window.forget();
+}
+
+@implementation WindowDelegate
+
+// We try to find a gecko menu bar to paint. If one does not exist, just paint
+// the application menu by itself so that a window doesn't have some other
+// window's menu bar.
++ (void)paintMenubarForWindow:(NSWindow*)aWindow {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // make sure we only act on windows that have this kind of
+  // object as a delegate
+  id windowDelegate = [aWindow delegate];
+  if ([windowDelegate class] != [self class]) return;
+
+  nsCocoaWindow* geckoWidget = [windowDelegate geckoWidget];
+  NS_ASSERTION(geckoWidget, "Window delegate not returning a gecko widget!");
+
+  nsMenuBarX* geckoMenuBar = geckoWidget->GetMenuBar();
+  if (geckoMenuBar) {
+    geckoMenuBar->Paint();
+  } else {
+    // sometimes we don't have a native application menu early in launching
+    if (!sApplicationMenu) return;
+
+    NSMenu* mainMenu = [NSApp mainMenu];
+    NS_ASSERTION(
+        [mainMenu numberOfItems] > 0,
+        "Main menu does not have any items, something is terribly wrong!");
+
+    // Create a new menu bar.
+    // We create a GeckoNSMenu because all menu bar NSMenu objects should use
+    // that subclass for key handling reasons.
+    GeckoNSMenu* newMenuBar =
+        [[GeckoNSMenu alloc] initWithTitle:@"MainMenuBar"];
+
+    // move the application menu from the existing menu bar to the new one
+    NSMenuItem* firstMenuItem = [[mainMenu itemAtIndex:0] retain];
+    [mainMenu removeItemAtIndex:0];
+    [newMenuBar insertItem:firstMenuItem atIndex:0];
+    [firstMenuItem release];
+
+    // set our new menu bar as the main menu
+    [NSApp setMainMenu:newMenuBar];
+    [newMenuBar release];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (id)initWithGeckoWindow:(nsCocoaWindow*)geckoWind {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  [super init];
+  mGeckoWindow = geckoWind;
+  mToplevelActiveState = false;
+  mHasEverBeenZoomed = false;
+  return self;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (NSSize)windowWillResize:(NSWindow*)sender toSize:(NSSize)proposedFrameSize {
+  RollUpPopups();
+  return proposedFrameSize;
+}
+
+- (NSRect)windowWillUseStandardFrame:(NSWindow*)window
+                        defaultFrame:(NSRect)newFrame {
+  // This function needs to return a rect representing the frame a window would
+  // have if it is in its "maximized" size mode. The parameter newFrame is
+  // supposed to be a frame representing the maximum window size on the screen
+  // where the window currently appears. However, in practice, newFrame can be a
+  // much smaller size. So, we ignore newframe and instead return the frame of
+  // the entire screen associated with the window. That frame is bigger than the
+  // window could actually be, due to the presence of the menubar and possibly
+  // the dock, but we never call this function directly, and Cocoa callers will
+  // shrink it to its true maximum size.
+  return window.screen.frame;
+}
+
+void nsCocoaWindow::CocoaSendToplevelActivateEvents() {
+  if (mWidgetListener) {
+    mWidgetListener->WindowActivated();
+  }
+}
+
+void nsCocoaWindow::CocoaSendToplevelDeactivateEvents() {
+  if (mWidgetListener) {
+    mWidgetListener->WindowDeactivated();
+  }
+}
+
+void nsCocoaWindow::CocoaWindowDidResize() {
+  // It's important to update our bounds before we trigger any listeners. This
+  // ensures that our bounds are correct when GetScreenBounds is called.
+  UpdateBounds();
+
+  if (HandleUpdateFullscreenOnResize()) {
+    ReportSizeEvent();
+    return;
+  }
+
+  // Resizing might have changed our zoom state.
+  DispatchSizeModeEvent();
+  ReportSizeEvent();
+}
+
+- (void)windowDidResize:(NSNotification*)aNotification {
+  BaseWindow* window = [aNotification object];
+  [window updateTrackingArea];
+
+  if (!mGeckoWindow) return;
+
+  mGeckoWindow->CocoaWindowDidResize();
+}
+
+- (void)windowDidChangeScreen:(NSNotification*)aNotification {
+  if (!mGeckoWindow) return;
+
+  // Because of Cocoa's peculiar treatment of zero-size windows (see comments
+  // at GetBackingScaleFactor() above), we sometimes have a situation where
+  // our concept of backing scale (based on the screen where the zero-sized
+  // window is positioned) differs from Cocoa's idea (always based on the
+  // Retina screen, AFAICT, even when an external non-Retina screen is the
+  // primary display).
+  //
+  // As a result, if the window was created with zero size on an external
+  // display, but then made visible on the (secondary) Retina screen, we
+  // will *not* get a windowDidChangeBackingProperties notification for it.
+  // This leads to an incorrect GetDefaultScale(), and widget coordinate
+  // confusion, as per bug 853252.
+  //
+  // To work around this, we check for a backing scale mismatch when we
+  // receive a windowDidChangeScreen notification, as we will receive this
+  // even if Cocoa was already treating the zero-size window as having
+  // Retina backing scale.
+  NSWindow* window = (NSWindow*)[aNotification object];
+  if ([window respondsToSelector:@selector(backingScaleFactor)]) {
+    if (GetBackingScaleFactor(window) != mGeckoWindow->BackingScaleFactor()) {
+      mGeckoWindow->BackingScaleFactorChanged();
+    }
+  }
+
+  mGeckoWindow->ReportMoveEvent();
+}
+
+- (void)windowWillEnterFullScreen:(NSNotification*)notification {
+  if (!mGeckoWindow) {
+    return;
+  }
+  mGeckoWindow->CocoaWindowWillEnterFullscreen(true);
+}
+
+// Lion's full screen mode will bypass our internal fullscreen tracking, so
+// we need to catch it when we transition and call our own methods, which in
+// turn will fire "fullscreen" events.
+- (void)windowDidEnterFullScreen:(NSNotification*)notification {
+  // On Yosemite, the NSThemeFrame class has two new properties --
+  // titlebarView (an NSTitlebarView object) and titlebarContainerView (an
+  // NSTitlebarContainerView object).  These are used to display the titlebar
+  // in fullscreen mode.  In Safari they're not transparent.  But in Firefox
+  // for some reason they are, which causes bug 1069658.  The following code
+  // works around this Apple bug or design flaw.
+  NSWindow* window = (NSWindow*)[notification object];
+  NSView* frameView = [[window contentView] superview];
+  NSView* titlebarView = nil;
+  NSView* titlebarContainerView = nil;
+  if ([frameView respondsToSelector:@selector(titlebarView)]) {
+    titlebarView = [frameView titlebarView];
+  }
+  if ([frameView respondsToSelector:@selector(titlebarContainerView)]) {
+    titlebarContainerView = [frameView titlebarContainerView];
+  }
+  if ([titlebarView respondsToSelector:@selector(setTransparent:)]) {
+    [titlebarView setTransparent:NO];
+  }
+  if ([titlebarContainerView respondsToSelector:@selector(setTransparent:)]) {
+    [titlebarContainerView setTransparent:NO];
+  }
+
+  if (!mGeckoWindow) {
+    return;
+  }
+  mGeckoWindow->CocoaWindowDidEnterFullscreen(true);
+}
+
+- (void)windowWillExitFullScreen:(NSNotification*)notification {
+  if (!mGeckoWindow) {
+    return;
+  }
+  mGeckoWindow->CocoaWindowWillEnterFullscreen(false);
+}
+
+- (void)windowDidExitFullScreen:(NSNotification*)notification {
+  if (!mGeckoWindow) {
+    return;
+  }
+  mGeckoWindow->CocoaWindowDidEnterFullscreen(false);
+}
+
+- (void)windowDidBecomeMain:(NSNotification*)aNotification {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  RollUpPopups();
+  ChildViewMouseTracker::ReEvaluateMouseEnterState();
+
+  // [NSApp _isRunningAppModal] will return true if we're running an OS dialog
+  // app modally. If one of those is up then we want it to retain its menu bar.
+  if ([NSApp _isRunningAppModal]) return;
+  NSWindow* window = [aNotification object];
+  if (window) [WindowDelegate paintMenubarForWindow:window];
+
+  if ([window isKindOfClass:[ToolbarWindow class]]) {
+    [(ToolbarWindow*)window windowMainStateChanged];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)windowDidResignMain:(NSNotification*)aNotification {
+  RollUpPopups();
+  ChildViewMouseTracker::ReEvaluateMouseEnterState();
+
+  // [NSApp _isRunningAppModal] will return true if we're running an OS dialog
+  // app modally. If one of those is up then we want it to retain its menu bar.
+  if ([NSApp _isRunningAppModal]) return;
+  RefPtr<nsMenuBarX> hiddenWindowMenuBar =
+      nsMenuUtilsX::GetHiddenWindowMenuBar();
+  if (hiddenWindowMenuBar) {
+    // printf("painting hidden window menu bar due to window losing main
+    // status\n");
+    hiddenWindowMenuBar->Paint();
+  }
+
+  NSWindow* window = [aNotification object];
+  if ([window isKindOfClass:[ToolbarWindow class]]) {
+    [(ToolbarWindow*)window windowMainStateChanged];
+  }
+}
+
+- (void)windowDidBecomeKey:(NSNotification*)aNotification {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  RollUpPopups();
+  ChildViewMouseTracker::ReEvaluateMouseEnterState();
+
+  NSWindow* window = [aNotification object];
+  if ([window isSheet]) [WindowDelegate paintMenubarForWindow:window];
+
+  nsChildView* mainChildView =
+      static_cast<nsChildView*>([[(BaseWindow*)window mainChildView] widget]);
+  if (mainChildView) {
+    if (mainChildView->GetInputContext().IsPasswordEditor()) {
+      TextInputHandler::EnableSecureEventInput();
+    } else {
+      TextInputHandler::EnsureSecureEventInputDisabled();
+    }
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)windowDidResignKey:(NSNotification*)aNotification {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  RollUpPopups(nsIRollupListener::AllowAnimations::No);
+
+  ChildViewMouseTracker::ReEvaluateMouseEnterState();
+
+  // If a sheet just resigned key then we should paint the menu bar
+  // for whatever window is now main.
+  NSWindow* window = [aNotification object];
+  if ([window isSheet])
+    [WindowDelegate paintMenubarForWindow:[NSApp mainWindow]];
+
+  TextInputHandler::EnsureSecureEventInputDisabled();
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)windowWillMove:(NSNotification*)aNotification {
+  RollUpPopups();
+}
+
+- (void)windowDidMove:(NSNotification*)aNotification {
+  if (mGeckoWindow) mGeckoWindow->ReportMoveEvent();
+}
+
+- (BOOL)windowShouldClose:(id)sender {
+  nsIWidgetListener* listener =
+      mGeckoWindow ? mGeckoWindow->GetWidgetListener() : nullptr;
+  if (listener) listener->RequestWindowClose(mGeckoWindow);
+  return NO;  // gecko will do it
+}
+
+- (void)windowWillClose:(NSNotification*)aNotification {
+  RollUpPopups();
+}
+
+- (void)windowWillMiniaturize:(NSNotification*)aNotification {
+  RollUpPopups();
+}
+
+- (void)windowDidMiniaturize:(NSNotification*)aNotification {
+  if (!mGeckoWindow) {
+    return;
+  }
+  mGeckoWindow->FinishCurrentTransitionIfMatching(
+      nsCocoaWindow::TransitionType::Miniaturize);
+}
+
+- (void)windowDidDeminiaturize:(NSNotification*)aNotification {
+  if (!mGeckoWindow) {
+    return;
+  }
+  mGeckoWindow->FinishCurrentTransitionIfMatching(
+      nsCocoaWindow::TransitionType::Deminiaturize);
+}
+
+- (BOOL)windowShouldZoom:(NSWindow*)window toFrame:(NSRect)proposedFrame {
+  if (!mHasEverBeenZoomed && [window isZoomed]) return NO;  // See bug 429954.
+
+  mHasEverBeenZoomed = YES;
+  return YES;
+}
+
+- (NSRect)window:(NSWindow*)window
+    willPositionSheet:(NSWindow*)sheet
+            usingRect:(NSRect)rect {
+  if ([window isKindOfClass:[ToolbarWindow class]]) {
+    rect.origin.y = [(ToolbarWindow*)window sheetAttachmentPosition];
+  }
+  return rect;
+}
+
+#ifdef MOZ_THUNDERBIRD
+- (void)didEndSheet:(NSWindow*)sheet
+         returnCode:(int)returnCode
+        contextInfo:(void*)contextInfo {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // Note: 'contextInfo' (if it is set) is the window that is the parent of
+  // the sheet.  The value of contextInfo is determined in
+  // nsCocoaWindow::Show().  If it's set, 'contextInfo' is always the top-
+  // level window, not another sheet itself.  But 'contextInfo' is nil if
+  // our parent window is also a sheet -- in that case we shouldn't send
+  // the top-level window any activate events (because it's our parent
+  // window that needs to get these events, not the top-level window).
+  [TopLevelWindowData deactivateInWindow:sheet];
+  [sheet orderOut:self];
+  if (contextInfo) [TopLevelWindowData activateInWindow:(NSWindow*)contextInfo];
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+#endif
+
+- (void)windowDidChangeBackingProperties:(NSNotification*)aNotification {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NSWindow* window = (NSWindow*)[aNotification object];
+
+  if ([window respondsToSelector:@selector(backingScaleFactor)]) {
+    CGFloat oldFactor = [[[aNotification userInfo]
+        objectForKey:@"NSBackingPropertyOldScaleFactorKey"] doubleValue];
+    if ([window backingScaleFactor] != oldFactor) {
+      mGeckoWindow->BackingScaleFactorChanged();
+    }
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// This method is on NSWindowDelegate starting with 10.9
+- (void)windowDidChangeOcclusionState:(NSNotification*)aNotification {
+  if (mGeckoWindow) {
+    mGeckoWindow->DispatchOcclusionEvent();
+  }
+}
+
+- (nsCocoaWindow*)geckoWidget {
+  return mGeckoWindow;
+}
+
+- (bool)toplevelActiveState {
+  return mToplevelActiveState;
+}
+
+- (void)sendToplevelActivateEvents {
+  if (!mToplevelActiveState && mGeckoWindow) {
+    mGeckoWindow->CocoaSendToplevelActivateEvents();
+
+    mToplevelActiveState = true;
+  }
+}
+
+- (void)sendToplevelDeactivateEvents {
+  if (mToplevelActiveState && mGeckoWindow) {
+    mGeckoWindow->CocoaSendToplevelDeactivateEvents();
+    mToplevelActiveState = false;
+  }
+}
+
+@end
+
+@interface NSView (FrameViewMethodSwizzling)
+- (NSPoint)FrameView__closeButtonOrigin;
+- (CGFloat)FrameView__titlebarHeight;
+@end
+
+@implementation NSView (FrameViewMethodSwizzling)
+
+- (NSPoint)FrameView__closeButtonOrigin {
+  if (![self.window isKindOfClass:[ToolbarWindow class]]) {
+    return self.FrameView__closeButtonOrigin;
+  }
+  ToolbarWindow* win = (ToolbarWindow*)[self window];
+  if (win.drawsContentsIntoWindowFrame &&
+      !(win.styleMask & NSWindowStyleMaskFullScreen) &&
+      (win.styleMask & NSWindowStyleMaskTitled)) {
+    const NSRect buttonsRect = win.windowButtonsRect;
+    if (NSIsEmptyRect(buttonsRect)) {
+      // Empty rect. Let's hide the buttons.
+      // Position is in non-flipped window coordinates. Using frame's height
+      // for the vertical coordinate will move the buttons above the window,
+      // making them invisible.
+      return NSMakePoint(buttonsRect.origin.x, win.frame.size.height);
+    } else if (win.windowTitlebarLayoutDirection ==
+               NSUserInterfaceLayoutDirectionRightToLeft) {
+      // We're in RTL mode, which means that the close button is the rightmost
+      // button of the three window buttons. and buttonsRect.origin is the
+      // bottom left corner of the green (zoom) button. The close button is 40px
+      // to the right of the zoom button. This is confirmed to be the same on
+      // all macOS versions between 10.12 - 12.0.
+      return NSMakePoint(buttonsRect.origin.x + 40.0f, buttonsRect.origin.y);
+    }
+    return buttonsRect.origin;
+  }
+  return self.FrameView__closeButtonOrigin;
+}
+
+- (CGFloat)FrameView__titlebarHeight {
+  CGFloat height = [self FrameView__titlebarHeight];
+  if ([[self window] isKindOfClass:[ToolbarWindow class]]) {
+    // Make sure that the titlebar height includes our shifted buttons.
+    // The following coordinates are in window space, with the origin being at
+    // the bottom left corner of the window.
+    ToolbarWindow* win = (ToolbarWindow*)[self window];
+    CGFloat frameHeight = [self frame].size.height;
+    CGFloat windowButtonY = frameHeight;
+    if (!NSIsEmptyRect(win.windowButtonsRect) &&
+        win.drawsContentsIntoWindowFrame &&
+        !(win.styleMask & NSWindowStyleMaskFullScreen) &&
+        (win.styleMask & NSWindowStyleMaskTitled)) {
+      windowButtonY = win.windowButtonsRect.origin.y;
+    }
+    height = std::max(height, frameHeight - windowButtonY);
+  }
+  return height;
+}
+
+@end
+
+static NSMutableSet* gSwizzledFrameViewClasses = nil;
+
+@interface NSWindow (PrivateSetNeedsDisplayInRectMethod)
+- (void)_setNeedsDisplayInRect:(NSRect)aRect;
+@end
+
+@interface NSView (NSVisualEffectViewSetMaskImage)
+- (void)setMaskImage:(NSImage*)image;
+@end
+
+@interface BaseWindow (Private)
+- (void)removeTrackingArea;
+- (void)cursorUpdated:(NSEvent*)aEvent;
+- (void)reflowTitlebarElements;
+@end
+
+@implementation BaseWindow
+
+// The frame of a window is implemented using undocumented NSView subclasses.
+// We offset the window buttons by overriding the method _closeButtonOrigin on
+// these frame view classes. The class which is
+// used for a window is determined in the window's frameViewClassForStyleMask:
+// method, so this is where we make sure that we have swizzled the method on
+// all encountered classes.
++ (Class)frameViewClassForStyleMask:(NSUInteger)styleMask {
+  Class frameViewClass = [super frameViewClassForStyleMask:styleMask];
+
+  if (!gSwizzledFrameViewClasses) {
+    gSwizzledFrameViewClasses = [[NSMutableSet setWithCapacity:3] retain];
+    if (!gSwizzledFrameViewClasses) {
+      return frameViewClass;
+    }
+  }
+
+  static IMP our_closeButtonOrigin = class_getMethodImplementation(
+      [NSView class], @selector(FrameView__closeButtonOrigin));
+  static IMP our_titlebarHeight = class_getMethodImplementation(
+      [NSView class], @selector(FrameView__titlebarHeight));
+
+  if (![gSwizzledFrameViewClasses containsObject:frameViewClass]) {
+    // Either of these methods might be implemented in both a subclass of
+    // NSFrameView and one of its own subclasses.  Which means that if we
+    // aren't careful we might end up swizzling the same method twice.
+    // Since method swizzling involves swapping pointers, this would break
+    // things.
+    IMP _closeButtonOrigin = class_getMethodImplementation(
+        frameViewClass, @selector(_closeButtonOrigin));
+    if (_closeButtonOrigin && _closeButtonOrigin != our_closeButtonOrigin) {
+      nsToolkit::SwizzleMethods(frameViewClass, @selector(_closeButtonOrigin),
+                                @selector(FrameView__closeButtonOrigin));
+    }
+
+    // Override _titlebarHeight so that the floating titlebar doesn't clip the
+    // bottom of the window buttons which we move down with our override of
+    // _closeButtonOrigin.
+    IMP _titlebarHeight = class_getMethodImplementation(
+        frameViewClass, @selector(_titlebarHeight));
+    if (_titlebarHeight && _titlebarHeight != our_titlebarHeight) {
+      nsToolkit::SwizzleMethods(frameViewClass, @selector(_titlebarHeight),
+                                @selector(FrameView__titlebarHeight));
+    }
+
+    [gSwizzledFrameViewClasses addObject:frameViewClass];
+  }
+
+  return frameViewClass;
+}
+
+- (id)initWithContentRect:(NSRect)aContentRect
+                styleMask:(NSUInteger)aStyle
+                  backing:(NSBackingStoreType)aBufferingType
+                    defer:(BOOL)aFlag {
+  mDrawsIntoWindowFrame = NO;
+  [super initWithContentRect:aContentRect
+                   styleMask:aStyle
+                     backing:aBufferingType
+                       defer:aFlag];
+  mState = nil;
+  mDisabledNeedsDisplay = NO;
+  mTrackingArea = nil;
+  mDirtyRect = NSZeroRect;
+  mBeingShown = NO;
+  mDrawTitle = NO;
+  mTouchBar = nil;
+  mIsAnimationSuppressed = NO;
+  [self updateTrackingArea];
+
+  return self;
+}
+
+// Returns an autoreleased NSImage.
+static NSImage* GetMenuMaskImage() {
+  const CGFloat radius = 6.0f;
+  const NSSize maskSize = {radius * 3.0f, radius * 3.0f};
+  NSImage* maskImage = [NSImage imageWithSize:maskSize
+                                      flipped:FALSE
+                               drawingHandler:^BOOL(NSRect dstRect) {
+                                 NSBezierPath* path = [NSBezierPath
+                                     bezierPathWithRoundedRect:dstRect
+                                                       xRadius:radius
+                                                       yRadius:radius];
+                                 [NSColor.blackColor set];
+                                 [path fill];
+                                 return YES;
+                               }];
+  maskImage.capInsets = NSEdgeInsetsMake(radius, radius, radius, radius);
+  return maskImage;
+}
+
+- (void)swapOutChildViewWrapper:(NSView*)aNewWrapper {
+  [aNewWrapper setFrame:[[self contentView] frame]];
+  NSView* childView = [[self mainChildView] retain];
+  [childView removeFromSuperview];
+  [aNewWrapper addSubview:childView];
+  [childView release];
+  [super setContentView:aNewWrapper];
+}
+
+- (void)setEffectViewWrapperForStyle:(WindowShadow)aStyle {
+  if (aStyle == WindowShadow::Menu || aStyle == WindowShadow::Tooltip) {
+    // Add an effect view wrapper so that the OS draws the appropriate
+    // vibrancy effect and window border.
+    BOOL isMenu = aStyle == WindowShadow::Menu;
+    NSView* effectView = VibrancyManager::CreateEffectView(
+        isMenu ? VibrancyType::MENU : VibrancyType::TOOLTIP, YES);
+    if (isMenu) {
+      // Turn on rounded corner masking.
+      [effectView setMaskImage:GetMenuMaskImage()];
+    }
+    [self swapOutChildViewWrapper:effectView];
+    [effectView release];
+  } else {
+    // Remove the existing wrapper.
+    NSView* wrapper = [[NSView alloc] initWithFrame:NSZeroRect];
+    [wrapper setWantsLayer:YES];
+    [self swapOutChildViewWrapper:wrapper];
+    [wrapper release];
+  }
+}
+
+- (NSTouchBar*)makeTouchBar {
+  mTouchBar = [[nsTouchBar alloc] init];
+  if (mTouchBar) {
+    sTouchBarIsInitialized = YES;
+  }
+  return mTouchBar;
+}
+
+- (void)setBeingShown:(BOOL)aValue {
+  mBeingShown = aValue;
+}
+
+- (BOOL)isBeingShown {
+  return mBeingShown;
+}
+
+- (BOOL)isVisibleOrBeingShown {
+  return [super isVisible] || mBeingShown;
+}
+
+- (void)setIsAnimationSuppressed:(BOOL)aValue {
+  mIsAnimationSuppressed = aValue;
+}
+
+- (BOOL)isAnimationSuppressed {
+  return mIsAnimationSuppressed;
+}
+
+- (void)disableSetNeedsDisplay {
+  mDisabledNeedsDisplay = YES;
+}
+
+- (void)enableSetNeedsDisplay {
+  mDisabledNeedsDisplay = NO;
+}
+
+- (void)dealloc {
+  [mTouchBar release];
+  [self removeTrackingArea];
+  ChildViewMouseTracker::OnDestroyWindow(self);
+  [super dealloc];
+}
+
+static const NSString* kStateTitleKey = @"title";
+static const NSString* kStateDrawsContentsIntoWindowFrameKey =
+    @"drawsContentsIntoWindowFrame";
+static const NSString* kStateShowsToolbarButton = @"showsToolbarButton";
+static const NSString* kStateCollectionBehavior = @"collectionBehavior";
+static const NSString* kStateWantsTitleDrawn = @"wantsTitleDrawn";
+
+- (void)importState:(NSDictionary*)aState {
+  if (NSString* title = [aState objectForKey:kStateTitleKey]) {
+    [self setTitle:title];
+  }
+  [self setDrawsContentsIntoWindowFrame:
+            [[aState objectForKey:kStateDrawsContentsIntoWindowFrameKey]
+                boolValue]];
+  [self setShowsToolbarButton:[[aState objectForKey:kStateShowsToolbarButton]
+                                  boolValue]];
+  [self setCollectionBehavior:[[aState objectForKey:kStateCollectionBehavior]
+                                  unsignedIntValue]];
+  [self setWantsTitleDrawn:[[aState objectForKey:kStateWantsTitleDrawn]
+                               boolValue]];
+}
+
+- (NSMutableDictionary*)exportState {
+  NSMutableDictionary* state = [NSMutableDictionary dictionaryWithCapacity:10];
+  if (NSString* title = [self title]) {
+    [state setObject:title forKey:kStateTitleKey];
+  }
+  [state setObject:[NSNumber numberWithBool:[self drawsContentsIntoWindowFrame]]
+            forKey:kStateDrawsContentsIntoWindowFrameKey];
+  [state setObject:[NSNumber numberWithBool:[self showsToolbarButton]]
+            forKey:kStateShowsToolbarButton];
+  [state setObject:[NSNumber numberWithUnsignedInt:[self collectionBehavior]]
+            forKey:kStateCollectionBehavior];
+  [state setObject:[NSNumber numberWithBool:[self wantsTitleDrawn]]
+            forKey:kStateWantsTitleDrawn];
+  return state;
+}
+
+- (void)setDrawsContentsIntoWindowFrame:(BOOL)aState {
+  bool changed = (aState != mDrawsIntoWindowFrame);
+  mDrawsIntoWindowFrame = aState;
+  if (changed) {
+    [self reflowTitlebarElements];
+  }
+}
+
+- (BOOL)drawsContentsIntoWindowFrame {
+  return mDrawsIntoWindowFrame;
+}
+
+- (NSRect)childViewRectForFrameRect:(NSRect)aFrameRect {
+  if (mDrawsIntoWindowFrame) {
+    return aFrameRect;
+  }
+  NSUInteger styleMask = [self styleMask];
+  styleMask &= ~NSWindowStyleMaskFullSizeContentView;
+  return [NSWindow contentRectForFrameRect:aFrameRect styleMask:styleMask];
+}
+
+- (NSRect)frameRectForChildViewRect:(NSRect)aChildViewRect {
+  if (mDrawsIntoWindowFrame) {
+    return aChildViewRect;
+  }
+  NSUInteger styleMask = [self styleMask];
+  styleMask &= ~NSWindowStyleMaskFullSizeContentView;
+  return [NSWindow frameRectForContentRect:aChildViewRect styleMask:styleMask];
+}
+
+- (NSTimeInterval)animationResizeTime:(NSRect)newFrame {
+  if (mIsAnimationSuppressed) {
+    // Should not animate the initial session-restore size change
+    return 0.0;
+  }
+
+  return [super animationResizeTime:newFrame];
+}
+
+- (void)setWantsTitleDrawn:(BOOL)aDrawTitle {
+  mDrawTitle = aDrawTitle;
+  [self setTitleVisibility:mDrawTitle ? NSWindowTitleVisible
+                                      : NSWindowTitleHidden];
+}
+
+- (BOOL)wantsTitleDrawn {
+  return mDrawTitle;
+}
+
+- (NSView*)trackingAreaView {
+  NSView* contentView = [self contentView];
+  return [contentView superview] ? [contentView superview] : contentView;
+}
+
+- (NSArray<NSView*>*)contentViewContents {
+  return [[[[self contentView] subviews] copy] autorelease];
+}
+
+- (ChildView*)mainChildView {
+  NSView* contentView = [self contentView];
+  NSView* lastView = [[contentView subviews] lastObject];
+  if ([lastView isKindOfClass:[ChildView class]]) {
+    return (ChildView*)lastView;
+  }
+  return nil;
+}
+
+- (void)removeTrackingArea {
+  if (mTrackingArea) {
+    [[self trackingAreaView] removeTrackingArea:mTrackingArea];
+    [mTrackingArea release];
+    mTrackingArea = nil;
+  }
+}
+
+- (void)updateTrackingArea {
+  [self removeTrackingArea];
+
+  NSView* view = [self trackingAreaView];
+  const NSTrackingAreaOptions options = NSTrackingMouseEnteredAndExited |
+                                        NSTrackingMouseMoved |
+                                        NSTrackingActiveAlways;
+  mTrackingArea = [[NSTrackingArea alloc] initWithRect:[view bounds]
+                                               options:options
+                                                 owner:self
+                                              userInfo:nil];
+  [view addTrackingArea:mTrackingArea];
+}
+
+- (void)mouseEntered:(NSEvent*)aEvent {
+  ChildViewMouseTracker::MouseEnteredWindow(aEvent);
+}
+
+- (void)mouseExited:(NSEvent*)aEvent {
+  ChildViewMouseTracker::MouseExitedWindow(aEvent);
+}
+
+- (void)mouseMoved:(NSEvent*)aEvent {
+  ChildViewMouseTracker::MouseMoved(aEvent);
+}
+
+- (void)cursorUpdated:(NSEvent*)aEvent {
+  // Nothing to do here, but NSTrackingArea wants us to implement this method.
+}
+
+- (void)_setNeedsDisplayInRect:(NSRect)aRect {
+  // Prevent unnecessary invalidations due to moving NSViews (e.g. for plugins)
+  if (!mDisabledNeedsDisplay) {
+    // This method is only called by Cocoa, so when we're here, we know that
+    // it's available and don't need to check whether our superclass responds
+    // to the selector.
+    [super _setNeedsDisplayInRect:aRect];
+    mDirtyRect = NSUnionRect(mDirtyRect, aRect);
+  }
+}
+
+- (NSRect)getAndResetNativeDirtyRect {
+  NSRect dirtyRect = mDirtyRect;
+  mDirtyRect = NSZeroRect;
+  return dirtyRect;
+}
+
+// Possibly move the titlebar buttons.
+- (void)reflowTitlebarElements {
+  NSView* frameView = [[self contentView] superview];
+  if ([frameView respondsToSelector:@selector(_tileTitlebarAndRedisplay:)]) {
+    [frameView _tileTitlebarAndRedisplay:NO];
+  }
+}
+
+- (BOOL)respondsToSelector:(SEL)aSelector {
+  // Claim the window doesn't respond to this so that the system
+  // doesn't steal keyboard equivalents for it. Bug 613710.
+  if (aSelector == @selector(cancelOperation:)) {
+    return NO;
+  }
+
+  return [super respondsToSelector:aSelector];
+}
+
+- (void)doCommandBySelector:(SEL)aSelector {
+  // We override this so that it won't beep if it can't act.
+  // We want to control the beeping for missing or disabled
+  // commands ourselves.
+  [self tryToPerform:aSelector with:nil];
+}
+
+- (id)accessibilityAttributeValue:(NSString*)attribute {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  id retval = [super accessibilityAttributeValue:attribute];
+
+  // The following works around a problem with Text-to-Speech on OS X 10.7.
+  // See bug 674612 for more info.
+  //
+  // When accessibility is off, AXUIElementCopyAttributeValue(), when called
+  // on an AXApplication object to get its AXFocusedUIElement attribute,
+  // always returns an AXWindow object (the actual browser window -- never a
+  // mozAccessible object).  This also happens with accessibility turned on,
+  // if no other object in the browser window has yet been focused.  But if
+  // the browser window has a title bar (as it currently always does), the
+  // AXWindow object will always have four "accessible" children, one of which
+  // is an AXStaticText object (the title bar's "title"; the other three are
+  // the close, minimize and zoom buttons).  This means that (for complicated
+  // reasons, for which see bug 674612) Text-to-Speech on OS X 10.7 will often
+  // "speak" the window title, no matter what text is selected, or even if no
+  // text at all is selected.  (This always happens when accessibility is off.
+  // It doesn't happen in Firefox releases because Apple has (on OS X 10.7)
+  // special-cased the handling of apps whose CFBundleIdentifier is
+  // org.mozilla.firefox.)
+  //
+  // We work around this problem by only returning AXChildren that are
+  // mozAccessible object or are one of the titlebar's buttons (which
+  // instantiate subclasses of NSButtonCell).
+  if ([retval isKindOfClass:[NSArray class]] &&
+      [attribute isEqualToString:@"AXChildren"]) {
+    NSMutableArray* holder = [NSMutableArray arrayWithCapacity:10];
+    [holder addObjectsFromArray:(NSArray*)retval];
+    NSUInteger count = [holder count];
+    for (NSInteger i = count - 1; i >= 0; --i) {
+      id item = [holder objectAtIndex:i];
+      // Remove anything from holder that isn't one of the titlebar's buttons
+      // (which instantiate subclasses of NSButtonCell) or a mozAccessible
+      // object (or one of its subclasses).
+      if (![item isKindOfClass:[NSButtonCell class]] &&
+          ![item respondsToSelector:@selector(hasRepresentedView)]) {
+        [holder removeObjectAtIndex:i];
+      }
+    }
+    retval = [NSArray arrayWithArray:holder];
+  }
+
+  return retval;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (void)releaseJSObjects {
+  [mTouchBar releaseJSObjects];
+}
+
+@end
+
+@interface NSView (NSThemeFrame)
+- (void)_drawTitleStringInClip:(NSRect)aRect;
+- (void)_maskCorners:(NSUInteger)aFlags clipRect:(NSRect)aRect;
+@end
+
+@implementation MOZTitlebarView
+
+- (instancetype)initWithFrame:(NSRect)aFrame {
+  self = [super initWithFrame:aFrame];
+
+  self.material = NSVisualEffectMaterialTitlebar;
+  self.blendingMode = NSVisualEffectBlendingModeWithinWindow;
+
+  // Add a separator line at the bottom of the titlebar. NSBoxSeparator isn't a
+  // perfect match for a native titlebar separator, but it's better than
+  // nothing. We really want the appearance that _NSTitlebarDecorationView
+  // creates with the help of CoreUI, but there's no public API for that.
+  NSBox* separatorLine =
+      [[NSBox alloc] initWithFrame:NSMakeRect(0, 0, aFrame.size.width, 1)];
+  separatorLine.autoresizingMask = NSViewWidthSizable | NSViewMaxYMargin;
+  separatorLine.boxType = NSBoxSeparator;
+  [self addSubview:separatorLine];
+  [separatorLine release];
+
+  return self;
+}
+
+- (BOOL)mouseDownCanMoveWindow {
+  return YES;
+}
+
+- (void)mouseUp:(NSEvent*)event {
+  if ([event clickCount] == 2) {
+    // Handle titlebar double click. We don't get the window's default behavior
+    // here because the window uses NSWindowStyleMaskFullSizeContentView, and
+    // this view (the titlebar gradient view) is technically part of the window
+    // "contents" (it's a subview of the content view).
+    if (nsCocoaUtils::ShouldZoomOnTitlebarDoubleClick()) {
+      [[self window] performZoom:nil];
+    } else if (nsCocoaUtils::ShouldMinimizeOnTitlebarDoubleClick()) {
+      [[self window] performMiniaturize:nil];
+    }
+  }
+}
+
+@end
+
+@interface MOZTitlebarAccessoryView : NSView
+@end
+
+@implementation MOZTitlebarAccessoryView : NSView
+- (void)viewWillMoveToWindow:(NSWindow*)aWindow {
+  if (aWindow) {
+    // When entering full screen mode, titlebar accessory views are inserted
+    // into a floating NSWindow which houses the window titlebar and toolbars.
+    // In order to work around a drawing bug with titlebarAppearsTransparent
+    // windows in full screen mode, disable titlebar separators for all
+    // NSWindows that this view is used in, including the floating full screen
+    // toolbar window. The drawing bug was filed as FB9056136. See bug 1700211
+    // for more details.
+    if (@available(macOS 11.0, *)) {
+      aWindow.titlebarSeparatorStyle = NSTitlebarSeparatorStyleNone;
+    }
+  }
+}
+@end
+
+@implementation FullscreenTitlebarTracker
+- (FullscreenTitlebarTracker*)init {
+  [super init];
+  self.view =
+      [[[MOZTitlebarAccessoryView alloc] initWithFrame:NSZeroRect] autorelease];
+  self.hidden = YES;
+  return self;
+}
+@end
+
+// This class allows us to exercise control over the window's title bar. It is
+// used for all windows with titlebars.
+//
+// ToolbarWindow supports two modes:
+//  - drawsContentsIntoWindowFrame mode: In this mode, the Gecko ChildView is
+//    sized to cover the entire window frame and manages titlebar drawing.
+//  - separate titlebar mode, with support for unified toolbars: In this mode,
+//    the Gecko ChildView does not extend into the titlebar. However, this
+//    window's content view (which is the ChildView's superview) *does* extend
+//    into the titlebar. Moreover, in this mode, we place a MOZTitlebarView
+//    in the content view, as a sibling of the ChildView.
+//
+// The "separate titlebar mode" supports the "unified toolbar" look:
+// If there's a toolbar right below the titlebar, the two can "connect" and
+// form a single gradient without a separator line in between.
+//
+// The following mechanism communicates the height of the unified toolbar to
+// the ToolbarWindow:
+//
+// 1) In the style sheet we set the toolbar's -moz-appearance to toolbar.
+// 2) When the toolbar is visible and we paint the application chrome
+//    window, the array that Gecko passes nsChildView::UpdateThemeGeometries
+//    will contain an entry for the widget type StyleAppearance::Toolbar.
+// 3) nsChildView::UpdateThemeGeometries passes the toolbar's height, plus the
+//    titlebar height, to -[ToolbarWindow setUnifiedToolbarHeight:].
+//
+// The actual drawing of the gradient happens in two parts: The titlebar part
+// (i.e. the top 22 pixels of the gradient) is drawn by the MOZTitlebarView,
+// which is a subview of the window's content view and a sibling of the
+// ChildView. The rest of the gradient is drawn by Gecko into the ChildView, as
+// part of the -moz-appearance rendering of the toolbar.
+@implementation ToolbarWindow
+
+- (id)initWithContentRect:(NSRect)aChildViewRect
+                styleMask:(NSUInteger)aStyle
+                  backing:(NSBackingStoreType)aBufferingType
+                    defer:(BOOL)aFlag {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // We treat aChildViewRect as the rectangle that the window's main ChildView
+  // should be sized to. Get the right frameRect for the requested child view
+  // rect.
+  NSRect frameRect = [NSWindow frameRectForContentRect:aChildViewRect
+                                             styleMask:aStyle];
+
+  // Always size the content view to the full frame size of the window.
+  // We do this even if we want this window to have a titlebar; in that case,
+  // the window's content view covers the entire window but the ChildView inside
+  // it will only cover the content area. We do this so that we can render the
+  // titlebar gradient manually, with a subview of our content view that's
+  // positioned in the titlebar area. This lets us have a smooth connection
+  // between titlebar and toolbar gradient in case the window has a "unified
+  // toolbar + titlebar" look. Moreover, always using a full size content view
+  // lets us toggle the titlebar on and off without changing the window's style
+  // mask (which would have other subtle effects, for example on keyboard
+  // focus).
+  aStyle |= NSWindowStyleMaskFullSizeContentView;
+
+  // -[NSWindow initWithContentRect:styleMask:backing:defer:] calls
+  // [self frameRectForContentRect:styleMask:] to convert the supplied content
+  // rect to the window's frame rect. We've overridden that method to be a
+  // pass-through function. So, in order to get the intended frameRect, we need
+  // to supply frameRect itself as the "content rect".
+  NSRect contentRect = frameRect;
+
+  if ((self = [super initWithContentRect:contentRect
+                               styleMask:aStyle
+                                 backing:aBufferingType
+                                   defer:aFlag])) {
+    mTitlebarView = nil;
+    mUnifiedToolbarHeight = 22.0f;
+    mSheetAttachmentPosition = aChildViewRect.size.height;
+    mWindowButtonsRect = NSZeroRect;
+    mInitialTitlebarHeight = [self titlebarHeight];
+
+    [self setTitlebarAppearsTransparent:YES];
+    if (@available(macOS 11.0, *)) {
+      self.titlebarSeparatorStyle = NSTitlebarSeparatorStyleNone;
+    }
+    [self updateTitlebarView];
+
+    mFullscreenTitlebarTracker = [[FullscreenTitlebarTracker alloc] init];
+    // revealAmount is an undocumented property of
+    // NSTitlebarAccessoryViewController that updates whenever the menubar
+    // slides down in fullscreen mode.
+    [mFullscreenTitlebarTracker addObserver:self
+                                 forKeyPath:@"revealAmount"
+                                    options:NSKeyValueObservingOptionNew
+                                    context:nil];
+    // Adding this accessory view controller allows us to shift the toolbar down
+    // when the user mouses to the top of the screen in fullscreen.
+    [(NSWindow*)self
+        addTitlebarAccessoryViewController:mFullscreenTitlebarTracker];
+  }
+  return self;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (void)observeValueForKeyPath:(NSString*)keyPath
+                      ofObject:(id)object
+                        change:(NSDictionary<NSKeyValueChangeKey, id>*)change
+                       context:(void*)context {
+  if ([keyPath isEqualToString:@"revealAmount"]) {
+    [[self mainChildView] ensureNextCompositeIsAtomicWithMainThreadPaint];
+    NSNumber* revealAmount = (change[NSKeyValueChangeNewKey]);
+    [self updateTitlebarShownAmount:[revealAmount doubleValue]];
+  } else {
+    [super observeValueForKeyPath:keyPath
+                         ofObject:object
+                           change:change
+                          context:context];
+  }
+}
+
+static bool ScreenHasNotch(nsCocoaWindow* aGeckoWindow) {
+  if (@available(macOS 12.0, *)) {
+    nsCOMPtr<nsIScreen> widgetScreen = aGeckoWindow->GetWidgetScreen();
+    NSScreen* cocoaScreen =
+        ScreenHelperCocoa::CocoaScreenForScreen(widgetScreen);
+    return cocoaScreen.safeAreaInsets.top != 0.0f;
+  }
+  return false;
+}
+
+static bool ShouldShiftByMenubarHeightInFullscreen(nsCocoaWindow* aWindow) {
+  switch (StaticPrefs::widget_macos_shift_by_menubar_on_fullscreen()) {
+    case 0:
+      return false;
+    case 1:
+      return true;
+    default:
+      break;
+  }
+  // TODO: On notch-less macbooks, this creates extra space when the
+  // "automatically show and hide the menubar on fullscreen" option is unchecked
+  // (default checked). We tried to detect that in bug 1737831 but it wasn't
+  // reliable enough, see the regressions from that bug. For now, stick to the
+  // good behavior for default configurations (that is, shift by menubar height
+  // on notch-less macbooks, and don't for devices that have a notch). This will
+  // need refinement in the future.
+  return !ScreenHasNotch(aWindow);
+}
+
+- (void)updateTitlebarShownAmount:(CGFloat)aShownAmount {
+  NSInteger styleMask = [self styleMask];
+  if (!(styleMask & NSWindowStyleMaskFullScreen)) {
+    // We are not interested in the size of the titlebar unless we are in
+    // fullscreen.
+    return;
+  }
+
+  // [NSApp mainMenu] menuBarHeight] returns one of two values: the full height
+  // if the menubar is shown or is in the process of being shown, and 0
+  // otherwise. Since we are multiplying the menubar height by aShownAmount, we
+  // always want the full height.
+  CGFloat menuBarHeight = NSApp.mainMenu.menuBarHeight;
+  if (menuBarHeight > 0.0f) {
+    mMenuBarHeight = menuBarHeight;
+  }
+  if ([[self delegate] isKindOfClass:[WindowDelegate class]]) {
+    WindowDelegate* windowDelegate = (WindowDelegate*)[self delegate];
+    nsCocoaWindow* geckoWindow = [windowDelegate geckoWidget];
+    if (!geckoWindow) {
+      return;
+    }
+
+    if (nsIWidgetListener* listener = geckoWindow->GetWidgetListener()) {
+      // Use the titlebar height cached in our frame rather than
+      // [ToolbarWindow titlebarHeight]. titlebarHeight returns 0 when we're in
+      // fullscreen.
+      CGFloat shiftByPixels = mInitialTitlebarHeight * aShownAmount;
+      if (ShouldShiftByMenubarHeightInFullscreen(geckoWindow)) {
+        shiftByPixels += mMenuBarHeight * aShownAmount;
+      }
+      // Use mozilla::DesktopToLayoutDeviceScale rather than the
+      // DesktopToLayoutDeviceScale in nsCocoaWindow. The latter accounts for
+      // screen DPI. We don't want that because the revealAmount property
+      // already accounts for it, so we'd be compounding DPI scales > 1.
+      mozilla::DesktopCoord coord = LayoutDeviceCoord(shiftByPixels) /
+                                    mozilla::DesktopToLayoutDeviceScale();
+
+      listener->MacFullscreenMenubarOverlapChanged(coord);
+    }
+  }
+}
+
+- (void)dealloc {
+  [mTitlebarView release];
+  [mFullscreenTitlebarTracker removeObserver:self forKeyPath:@"revealAmount"];
+  [mFullscreenTitlebarTracker removeFromParentViewController];
+  [mFullscreenTitlebarTracker release];
+
+  [super dealloc];
+}
+
+- (NSArray<NSView*>*)contentViewContents {
+  NSMutableArray<NSView*>* contents =
+      [[[self contentView] subviews] mutableCopy];
+  if (mTitlebarView) {
+    // Do not include the titlebar gradient view in the returned array.
+    [contents removeObject:mTitlebarView];
+  }
+  return [contents autorelease];
+}
+
+- (void)updateTitlebarView {
+  BOOL needTitlebarView =
+      ![self drawsContentsIntoWindowFrame] || mUnifiedToolbarHeight > 0;
+  if (needTitlebarView && !mTitlebarView) {
+    mTitlebarView =
+        [[MOZTitlebarView alloc] initWithFrame:[self unifiedToolbarRect]];
+    mTitlebarView.autoresizingMask = NSViewWidthSizable | NSViewMinYMargin;
+    [self.contentView addSubview:mTitlebarView
+                      positioned:NSWindowBelow
+                      relativeTo:nil];
+  } else if (needTitlebarView && mTitlebarView) {
+    mTitlebarView.frame = [self unifiedToolbarRect];
+  } else if (!needTitlebarView && mTitlebarView) {
+    [mTitlebarView removeFromSuperview];
+    [mTitlebarView release];
+    mTitlebarView = nil;
+  }
+}
+
+- (void)windowMainStateChanged {
+  [self setTitlebarNeedsDisplay];
+  [[self mainChildView] ensureNextCompositeIsAtomicWithMainThreadPaint];
+}
+
+- (void)setTitlebarNeedsDisplay {
+  [mTitlebarView setNeedsDisplay:YES];
+}
+
+- (NSRect)titlebarRect {
+  CGFloat titlebarHeight = [self titlebarHeight];
+  return NSMakeRect(0, [self frame].size.height - titlebarHeight,
+                    [self frame].size.width, titlebarHeight);
+}
+
+// In window contentView coordinates (origin bottom left)
+- (NSRect)unifiedToolbarRect {
+  return NSMakeRect(0, [self frame].size.height - mUnifiedToolbarHeight,
+                    [self frame].size.width, mUnifiedToolbarHeight);
+}
+
+// Returns the unified height of titlebar + toolbar.
+- (CGFloat)unifiedToolbarHeight {
+  return mUnifiedToolbarHeight;
+}
+
+- (CGFloat)titlebarHeight {
+  // We use the original content rect here, not what we return from
+  // [self contentRectForFrameRect:], because that would give us a
+  // titlebarHeight of zero.
+  NSRect frameRect = [self frame];
+  NSUInteger styleMask = [self styleMask];
+  styleMask &= ~NSWindowStyleMaskFullSizeContentView;
+  NSRect originalContentRect = [NSWindow contentRectForFrameRect:frameRect
+                                                       styleMask:styleMask];
+  return NSMaxY(frameRect) - NSMaxY(originalContentRect);
+}
+
+// Stores the complete height of titlebar + toolbar.
+- (void)setUnifiedToolbarHeight:(CGFloat)aHeight {
+  if (aHeight == mUnifiedToolbarHeight) return;
+
+  mUnifiedToolbarHeight = aHeight;
+
+  [self updateTitlebarView];
+}
+
+// Extending the content area into the title bar works by resizing the
+// mainChildView so that it covers the titlebar.
+- (void)setDrawsContentsIntoWindowFrame:(BOOL)aState {
+  BOOL stateChanged = ([self drawsContentsIntoWindowFrame] != aState);
+  [super setDrawsContentsIntoWindowFrame:aState];
+  if (stateChanged && [[self delegate] isKindOfClass:[WindowDelegate class]]) {
+    // Here we extend / shrink our mainChildView. We do that by firing a resize
+    // event which will cause the ChildView to be resized to the rect returned
+    // by nsCocoaWindow::GetClientBounds. GetClientBounds bases its return
+    // value on what we return from drawsContentsIntoWindowFrame.
+    WindowDelegate* windowDelegate = (WindowDelegate*)[self delegate];
+    nsCocoaWindow* geckoWindow = [windowDelegate geckoWidget];
+    if (geckoWindow) {
+      // Re-layout our contents.
+      geckoWindow->ReportSizeEvent();
+    }
+
+    // Resizing the content area causes a reflow which would send a synthesized
+    // mousemove event to the old mouse position relative to the top left
+    // corner of the content area. But the mouse has shifted relative to the
+    // content area, so that event would have wrong position information. So
+    // we'll send a mouse move event with the correct new position.
+    ChildViewMouseTracker::ResendLastMouseMoveEvent();
+  }
+
+  [self updateTitlebarView];
+}
+
+- (void)setWantsTitleDrawn:(BOOL)aDrawTitle {
+  [super setWantsTitleDrawn:aDrawTitle];
+  [self setTitlebarNeedsDisplay];
+}
+
+- (void)setSheetAttachmentPosition:(CGFloat)aY {
+  mSheetAttachmentPosition = aY;
+}
+
+- (CGFloat)sheetAttachmentPosition {
+  return mSheetAttachmentPosition;
+}
+
+- (void)placeWindowButtons:(NSRect)aRect {
+  if (!NSEqualRects(mWindowButtonsRect, aRect)) {
+    mWindowButtonsRect = aRect;
+    [self reflowTitlebarElements];
+  }
+}
+
+- (NSRect)windowButtonsRect {
+  return mWindowButtonsRect;
+}
+
+// Returning YES here makes the setShowsToolbarButton method work even though
+// the window doesn't contain an NSToolbar.
+- (BOOL)_hasToolbar {
+  return YES;
+}
+
+// Dispatch a toolbar pill button clicked message to Gecko.
+- (void)_toolbarPillButtonClicked:(id)sender {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  RollUpPopups();
+
+  if ([[self delegate] isKindOfClass:[WindowDelegate class]]) {
+    WindowDelegate* windowDelegate = (WindowDelegate*)[self delegate];
+    nsCocoaWindow* geckoWindow = [windowDelegate geckoWidget];
+    if (!geckoWindow) return;
+
+    nsIWidgetListener* listener = geckoWindow->GetWidgetListener();
+    if (listener) listener->OSToolbarButtonPressed();
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Retain and release "self" to avoid crashes when our widget (and its native
+// window) is closed as a result of processing a key equivalent (e.g.
+// Command+w or Command+q).  This workaround is only needed for a window
+// that can become key.
+- (BOOL)performKeyEquivalent:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSWindow* nativeWindow = [self retain];
+  BOOL retval = [super performKeyEquivalent:theEvent];
+  [nativeWindow release];
+  return retval;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NO);
+}
+
+- (void)sendEvent:(NSEvent*)anEvent {
+  NSEventType type = [anEvent type];
+
+  switch (type) {
+    case NSEventTypeScrollWheel:
+    case NSEventTypeLeftMouseDown:
+    case NSEventTypeLeftMouseUp:
+    case NSEventTypeRightMouseDown:
+    case NSEventTypeRightMouseUp:
+    case NSEventTypeOtherMouseDown:
+    case NSEventTypeOtherMouseUp:
+    case NSEventTypeMouseMoved:
+    case NSEventTypeLeftMouseDragged:
+    case NSEventTypeRightMouseDragged:
+    case NSEventTypeOtherMouseDragged: {
+      // Drop all mouse events if a modal window has appeared above us.
+      // This helps make us behave as if the OS were running a "real" modal
+      // event loop.
+      id delegate = [self delegate];
+      if (delegate && [delegate isKindOfClass:[WindowDelegate class]]) {
+        nsCocoaWindow* widget = [(WindowDelegate*)delegate geckoWidget];
+        if (widget) {
+          if (gGeckoAppModalWindowList &&
+              (widget != gGeckoAppModalWindowList->window))
+            return;
+          if (widget->HasModalDescendents()) return;
+        }
+      }
+      break;
+    }
+    default:
+      break;
+  }
+
+  [super sendEvent:anEvent];
+}
+
+@end
+
+@implementation PopupWindow
+
+- (id)initWithContentRect:(NSRect)contentRect
+                styleMask:(NSUInteger)styleMask
+                  backing:(NSBackingStoreType)bufferingType
+                    defer:(BOOL)deferCreation {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  mIsContextMenu = false;
+  return [super initWithContentRect:contentRect
+                          styleMask:styleMask
+                            backing:bufferingType
+                              defer:deferCreation];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+// Override the private API _backdropBleedAmount. This determines how much the
+// desktop wallpaper contributes to the vibrancy backdrop.
+// Return 0 in order to match what the system does for sheet windows and
+// _NSPopoverWindows.
+- (CGFloat)_backdropBleedAmount {
+  return 0.0;
+}
+
+// Override the private API shadowOptions.
+// The constants below were found in AppKit's implementations of the
+// shadowOptions method on the various window types.
+static const NSUInteger kWindowShadowOptionsNoShadow = 0;
+static const NSUInteger kWindowShadowOptionsMenu = 2;
+static const NSUInteger kWindowShadowOptionsTooltip = 4;
+
+- (NSDictionary*)shadowParameters {
+  NSDictionary* parent = [super shadowParameters];
+  // NSLog(@"%@", parent);
+  if (self.shadowStyle != WindowShadow::Panel) {
+    return parent;
+  }
+  NSMutableDictionary* copy = [parent mutableCopy];
+  for (auto* key : {@"com.apple.WindowShadowRimDensityActive",
+                    @"com.apple.WindowShadowRimDensityInactive"}) {
+    if ([parent objectForKey:key] != nil) {
+      [copy setValue:@(0) forKey:key];
+    }
+  }
+  return copy;
+}
+
+- (NSUInteger)shadowOptions {
+  if (!self.hasShadow) {
+    return kWindowShadowOptionsNoShadow;
+  }
+
+  switch (self.shadowStyle) {
+    case WindowShadow::None:
+      return kWindowShadowOptionsNoShadow;
+
+    case WindowShadow::Menu:
+    case WindowShadow::Panel:
+      return kWindowShadowOptionsMenu;
+
+    case WindowShadow::Tooltip:
+      return kWindowShadowOptionsTooltip;
+  }
+}
+
+- (BOOL)isContextMenu {
+  return mIsContextMenu;
+}
+
+- (void)setIsContextMenu:(BOOL)flag {
+  mIsContextMenu = flag;
+}
+
+- (BOOL)canBecomeMainWindow {
+  // This is overriden because the default is 'yes' when a titlebar is present.
+  return NO;
+}
+
+@end
+
+// According to Apple's docs on [NSWindow canBecomeKeyWindow] and [NSWindow
+// canBecomeMainWindow], windows without a title bar or resize bar can't (by
+// default) become key or main.  But if a window can't become key, it can't
+// accept keyboard input (bmo bug 393250).  And it should also be possible for
+// an otherwise "ordinary" window to become main.  We need to override these
+// two methods to make this happen.
+@implementation BorderlessWindow
+
+- (BOOL)canBecomeKeyWindow {
+  return YES;
+}
+
+- (void)sendEvent:(NSEvent*)anEvent {
+  NSEventType type = [anEvent type];
+
+  switch (type) {
+    case NSEventTypeScrollWheel:
+    case NSEventTypeLeftMouseDown:
+    case NSEventTypeLeftMouseUp:
+    case NSEventTypeRightMouseDown:
+    case NSEventTypeRightMouseUp:
+    case NSEventTypeOtherMouseDown:
+    case NSEventTypeOtherMouseUp:
+    case NSEventTypeMouseMoved:
+    case NSEventTypeLeftMouseDragged:
+    case NSEventTypeRightMouseDragged:
+    case NSEventTypeOtherMouseDragged: {
+      // Drop all mouse events if a modal window has appeared above us.
+      // This helps make us behave as if the OS were running a "real" modal
+      // event loop.
+      id delegate = [self delegate];
+      if (delegate && [delegate isKindOfClass:[WindowDelegate class]]) {
+        nsCocoaWindow* widget = [(WindowDelegate*)delegate geckoWidget];
+        if (widget) {
+          if (gGeckoAppModalWindowList &&
+              (widget != gGeckoAppModalWindowList->window))
+            return;
+          if (widget->HasModalDescendents()) return;
+        }
+      }
+      break;
+    }
+    default:
+      break;
+  }
+
+  [super sendEvent:anEvent];
+}
+
+// Apple's doc on this method says that the NSWindow class's default is not to
+// become main if the window isn't "visible" -- so we should replicate that
+// behavior here.  As best I can tell, the [NSWindow isVisible] method is an
+// accurate test of what Apple means by "visibility".
+- (BOOL)canBecomeMainWindow {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (![self isVisible]) return NO;
+  return YES;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NO);
+}
+
+// Retain and release "self" to avoid crashes when our widget (and its native
+// window) is closed as a result of processing a key equivalent (e.g.
+// Command+w or Command+q).  This workaround is only needed for a window
+// that can become key.
+- (BOOL)performKeyEquivalent:(NSEvent*)theEvent {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSWindow* nativeWindow = [self retain];
+  BOOL retval = [super performKeyEquivalent:theEvent];
+  [nativeWindow release];
+  return retval;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NO);
+}
+
+@end
diff --git a/widget/cocoa/nsColorPicker.h b/widget/cocoa/nsColorPicker.h
new file mode 100644
index 0000000000..325f159fde
--- /dev/null
+++ b/widget/cocoa/nsColorPicker.h
@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsColorPicker_h_
+#define nsColorPicker_h_
+
+#include "nsIColorPicker.h"
+#include "nsString.h"
+#include "nsCOMPtr.h"
+
+class nsIColorPickerShownCallback;
+class mozIDOMWindowProxy;
+@class NSColorPanelWrapper;
+@class NSColor;
+
+class nsColorPicker final : public nsIColorPicker {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSICOLORPICKER
+
+  // For NSColorPanelWrapper.
+  void Update(NSColor* aColor);
+  void Done();
+
+ private:
+  ~nsColorPicker();
+
+  static NSColor* GetNSColorFromHexString(const nsAString& aColor);
+  static void GetHexStringFromNSColor(NSColor* aColor, nsAString& aResult);
+
+  NSColorPanelWrapper* mColorPanelWrapper;
+
+  nsString mTitle;
+  nsString mColor;
+  nsCOMPtr<nsIColorPickerShownCallback> mCallback;
+};
+
+#endif  // nsColorPicker_h_
diff --git a/widget/cocoa/nsColorPicker.mm b/widget/cocoa/nsColorPicker.mm
new file mode 100644
index 0000000000..3666557772
--- /dev/null
+++ b/widget/cocoa/nsColorPicker.mm
@@ -0,0 +1,165 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsColorPicker.h"
+#include "nsCocoaUtils.h"
+#include "nsThreadUtils.h"
+
+using namespace mozilla;
+
+static unsigned int HexStrToInt(NSString* str) {
+  unsigned int result = 0;
+
+  for (unsigned int i = 0; i < [str length]; ++i) {
+    char c = [str characterAtIndex:i];
+    result *= 16;
+    if (c >= '0' && c <= '9') {
+      result += c - '0';
+    } else if (c >= 'A' && c <= 'F') {
+      result += 10 + (c - 'A');
+    } else {
+      result += 10 + (c - 'a');
+    }
+  }
+
+  return result;
+}
+
+@interface NSColorPanelWrapper : NSObject <NSWindowDelegate> {
+  NSColorPanel* mColorPanel;
+  nsColorPicker* mColorPicker;
+}
+- (id)initWithPicker:(nsColorPicker*)aPicker;
+- (void)open:(NSColor*)aInitialColor title:(NSString*)aTitle;
+- (void)colorChanged:(NSColorPanel*)aPanel;
+- (void)windowWillClose:(NSNotification*)aNotification;
+- (void)close;
+@end
+
+@implementation NSColorPanelWrapper
+- (id)initWithPicker:(nsColorPicker*)aPicker {
+  mColorPicker = aPicker;
+  mColorPanel = [NSColorPanel sharedColorPanel];
+
+  self = [super init];
+  return self;
+}
+
+- (void)open:(NSColor*)aInitialColor title:(NSString*)aTitle {
+  [mColorPanel setTarget:self];
+  [mColorPanel setAction:@selector(colorChanged:)];
+  [mColorPanel setDelegate:self];
+  [mColorPanel setTitle:aTitle];
+  [mColorPanel setColor:aInitialColor];
+  [mColorPanel setFrameOrigin:[NSEvent mouseLocation]];
+  [mColorPanel makeKeyAndOrderFront:nil];
+}
+
+- (void)colorChanged:(NSColorPanel*)aPanel {
+  if (!mColorPicker) {
+    return;
+  }
+  mColorPicker->Update([mColorPanel color]);
+}
+
+- (void)windowWillClose:(NSNotification*)aNotification {
+  if (!mColorPicker) {
+    return;
+  }
+  mColorPicker->Done();
+}
+
+- (void)close {
+  [mColorPanel setTarget:nil];
+  [mColorPanel setAction:nil];
+  [mColorPanel setDelegate:nil];
+
+  mColorPanel = nil;
+  mColorPicker = nullptr;
+}
+@end
+
+NS_IMPL_ISUPPORTS(nsColorPicker, nsIColorPicker)
+
+nsColorPicker::~nsColorPicker() {
+  if (mColorPanelWrapper) {
+    [mColorPanelWrapper close];
+    [mColorPanelWrapper release];
+    mColorPanelWrapper = nullptr;
+  }
+}
+
+// TODO(bug 1805397): Implement default colors
+NS_IMETHODIMP
+nsColorPicker::Init(mozIDOMWindowProxy* aParent, const nsAString& aTitle,
+                    const nsAString& aInitialColor,
+                    const nsTArray<nsString>& aDefaultColors) {
+  MOZ_ASSERT(NS_IsMainThread(),
+             "Color pickers can only be opened from main thread currently");
+  mTitle = aTitle;
+  mColor = aInitialColor;
+  mColorPanelWrapper = [[NSColorPanelWrapper alloc] initWithPicker:this];
+  return NS_OK;
+}
+
+/* static */ NSColor* nsColorPicker::GetNSColorFromHexString(
+    const nsAString& aColor) {
+  NSString* str = nsCocoaUtils::ToNSString(aColor);
+
+  double red = HexStrToInt([str substringWithRange:NSMakeRange(1, 2)]) / 255.0;
+  double green =
+      HexStrToInt([str substringWithRange:NSMakeRange(3, 2)]) / 255.0;
+  double blue = HexStrToInt([str substringWithRange:NSMakeRange(5, 2)]) / 255.0;
+
+  return [NSColor colorWithDeviceRed:red green:green blue:blue alpha:1.0];
+}
+
+/* static */ void nsColorPicker::GetHexStringFromNSColor(NSColor* aColor,
+                                                         nsAString& aResult) {
+  CGFloat redFloat, greenFloat, blueFloat;
+
+  NSColor* color = aColor;
+  @try {
+    [color getRed:&redFloat green:&greenFloat blue:&blueFloat alpha:nil];
+  } @catch (NSException* e) {
+    color = [color colorUsingColorSpace:[NSColorSpace genericRGBColorSpace]];
+    [color getRed:&redFloat green:&greenFloat blue:&blueFloat alpha:nil];
+  }
+
+  nsCocoaUtils::GetStringForNSString(
+      [NSString stringWithFormat:@"#%02x%02x%02x", (int)(redFloat * 255),
+                                 (int)(greenFloat * 255),
+                                 (int)(blueFloat * 255)],
+      aResult);
+}
+
+NS_IMETHODIMP
+nsColorPicker::Open(nsIColorPickerShownCallback* aCallback) {
+  MOZ_ASSERT(aCallback);
+  mCallback = aCallback;
+
+  [mColorPanelWrapper open:GetNSColorFromHexString(mColor)
+                     title:nsCocoaUtils::ToNSString(mTitle)];
+
+  NS_ADDREF_THIS();
+
+  return NS_OK;
+}
+
+void nsColorPicker::Update(NSColor* aColor) {
+  GetHexStringFromNSColor(aColor, mColor);
+  mCallback->Update(mColor);
+}
+
+void nsColorPicker::Done() {
+  [mColorPanelWrapper close];
+  [mColorPanelWrapper release];
+  mColorPanelWrapper = nullptr;
+  mCallback->Done(u""_ns);
+  mCallback = nullptr;
+  NS_RELEASE_THIS();
+}
diff --git a/widget/cocoa/nsCursorManager.h b/widget/cocoa/nsCursorManager.h
new file mode 100644
index 0000000000..cc42a3b842
--- /dev/null
+++ b/widget/cocoa/nsCursorManager.h
@@ -0,0 +1,63 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsCursorManager_h_
+#define nsCursorManager_h_
+
+#import <Foundation/Foundation.h>
+#include "nsIWidget.h"
+#include "nsMacCursor.h"
+
+/*! @class      nsCursorManager
+    @abstract   Singleton service provides access to all cursors available in
+   the application.
+    @discussion Use <code>nsCusorManager</code> to set the current cursor using
+                an XP <code>nsCusor</code> enum value.
+                <code>nsCursorManager</code> encapsulates the details of
+                setting different types of cursors, animating cursors and
+                cleaning up cursors when they are no longer in use.
+ */
+@interface nsCursorManager : NSObject {
+ @private
+  NSMutableDictionary* mCursors;
+  nsMacCursor* mCurrentMacCursor;
+}
+
+/*! @method     setCursor:
+    @abstract   Sets the current cursor.
+    @discussion Sets the current cursor to the cursor indicated by the XP
+                cursor given in the argument. Resources associated with the
+                previous cursor are cleaned up.
+    @param aCursor the cursor to use
+*/
+- (nsresult)setNonCustomCursor:(const nsIWidget::Cursor&)aCursor;
+
+// As above, but returns an error if the cursor isn't custom or we couldn't set
+// it for some reason.
+- (nsresult)setCustomCursor:(const nsIWidget::Cursor&)aCursor
+          widgetScaleFactor:(CGFloat)aWidgetScaleFactor
+                forceUpdate:(bool)aForceUpdate;
+
+/*! @method     sharedInstance
+    @abstract   Get the Singleton instance of the cursor manager.
+    @discussion Use this method to obtain a reference to the cursor manager.
+    @result a reference to the cursor manager
+*/
++ (nsCursorManager*)sharedInstance;
+
+/*! @method     dispose
+    @abstract   Releases the shared instance of the cursor manager.
+    @discussion Use dispose to clean up the cursor manager and associated
+   cursors.
+*/
++ (void)dispose;
+@end
+
+@interface NSCursor (Undocumented)
+// busyButClickableCursor is an undocumented NSCursor API, but has been in use
+// since at least OS X 10.4 and through 10.9.
++ (NSCursor*)busyButClickableCursor;
+@end
+
+#endif  // nsCursorManager_h_
diff --git a/widget/cocoa/nsCursorManager.mm b/widget/cocoa/nsCursorManager.mm
new file mode 100644
index 0000000000..2db20681ad
--- /dev/null
+++ b/widget/cocoa/nsCursorManager.mm
@@ -0,0 +1,363 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "imgIContainer.h"
+#include "nsCocoaUtils.h"
+#include "nsCursorManager.h"
+#include "nsObjCExceptions.h"
+#include <math.h>
+
+static nsCursorManager* gInstance;
+static CGFloat sCurrentCursorScaleFactor = 0.0f;
+static nsIWidget::Cursor sCurrentCursor;
+static constexpr nsCursor kCustomCursor = eCursorCount;
+
+/*! @category nsCursorManager(PrivateMethods)
+    Private methods for the cursor manager class.
+*/
+@interface nsCursorManager (PrivateMethods)
+/*! @method     getCursor:
+    @abstract   Get a reference to the native Mac representation of a cursor.
+    @discussion Gets a reference to the Mac native implementation of a cursor.
+                If the cursor has been requested before, it is retreived from
+                the cursor cache, otherwise it is created and cached.
+    @param      aCursor the cursor to get
+    @result     the Mac native implementation of the cursor
+*/
+- (nsMacCursor*)getCursor:(nsCursor)aCursor;
+
+/*! @method     setMacCursor:
+ @abstract   Set the current Mac native cursor
+ @discussion Sets the current cursor - this routine is what actually causes the
+             cursor to change. The argument is retained and the old cursor is
+             released.
+ @param      aMacCursor the cursor to set
+ @result     NS_OK
+ */
+- (nsresult)setMacCursor:(nsMacCursor*)aMacCursor;
+
+/*! @method     createCursor:
+    @abstract   Create a Mac native representation of a cursor.
+    @discussion Creates a version of the Mac native representation of this
+                cursor.
+    @param      aCursor the cursor to create
+    @result     the Mac native implementation of the cursor
+*/
++ (nsMacCursor*)createCursor:(enum nsCursor)aCursor;
+
+@end
+
+@implementation nsCursorManager
+
++ (nsCursorManager*)sharedInstance {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!gInstance) {
+    gInstance = [[nsCursorManager alloc] init];
+  }
+  return gInstance;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
++ (void)dispose {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [gInstance release];
+  gInstance = nil;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
++ (nsMacCursor*)createCursor:(enum nsCursor)aCursor {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  switch (aCursor) {
+    case eCursor_standard:
+      return [nsMacCursor cursorWithCursor:[NSCursor arrowCursor] type:aCursor];
+    case eCursor_wait:
+    case eCursor_spinning: {
+      return [nsMacCursor cursorWithCursor:[NSCursor busyButClickableCursor]
+                                      type:aCursor];
+    }
+    case eCursor_select:
+      return [nsMacCursor cursorWithCursor:[NSCursor IBeamCursor] type:aCursor];
+    case eCursor_hyperlink:
+      return [nsMacCursor cursorWithCursor:[NSCursor pointingHandCursor]
+                                      type:aCursor];
+    case eCursor_crosshair:
+      return [nsMacCursor cursorWithCursor:[NSCursor crosshairCursor]
+                                      type:aCursor];
+    case eCursor_move:
+      return [nsMacCursor cursorWithImageNamed:@"move"
+                                       hotSpot:NSMakePoint(12, 12)
+                                          type:aCursor];
+    case eCursor_help:
+      return [nsMacCursor cursorWithImageNamed:@"help"
+                                       hotSpot:NSMakePoint(12, 12)
+                                          type:aCursor];
+    case eCursor_copy: {
+      SEL cursorSelector = @selector(dragCopyCursor);
+      return [nsMacCursor
+          cursorWithCursor:[NSCursor respondsToSelector:cursorSelector]
+                               ? [NSCursor performSelector:cursorSelector]
+                               : [NSCursor arrowCursor]
+                      type:aCursor];
+    }
+    case eCursor_alias: {
+      SEL cursorSelector = @selector(dragLinkCursor);
+      return [nsMacCursor
+          cursorWithCursor:[NSCursor respondsToSelector:cursorSelector]
+                               ? [NSCursor performSelector:cursorSelector]
+                               : [NSCursor arrowCursor]
+                      type:aCursor];
+    }
+    case eCursor_context_menu: {
+      SEL cursorSelector = @selector(contextualMenuCursor);
+      return [nsMacCursor
+          cursorWithCursor:[NSCursor respondsToSelector:cursorSelector]
+                               ? [NSCursor performSelector:cursorSelector]
+                               : [NSCursor arrowCursor]
+                      type:aCursor];
+    }
+    case eCursor_cell:
+      return [nsMacCursor cursorWithImageNamed:@"cell"
+                                       hotSpot:NSMakePoint(12, 12)
+                                          type:aCursor];
+    case eCursor_grab:
+      return [nsMacCursor cursorWithCursor:[NSCursor openHandCursor]
+                                      type:aCursor];
+    case eCursor_grabbing:
+      return [nsMacCursor cursorWithCursor:[NSCursor closedHandCursor]
+                                      type:aCursor];
+    case eCursor_zoom_in:
+      return [nsMacCursor cursorWithImageNamed:@"zoomIn"
+                                       hotSpot:NSMakePoint(10, 10)
+                                          type:aCursor];
+    case eCursor_zoom_out:
+      return [nsMacCursor cursorWithImageNamed:@"zoomOut"
+                                       hotSpot:NSMakePoint(10, 10)
+                                          type:aCursor];
+    case eCursor_vertical_text:
+      return [nsMacCursor cursorWithImageNamed:@"vtIBeam"
+                                       hotSpot:NSMakePoint(12, 11)
+                                          type:aCursor];
+    case eCursor_all_scroll:
+      return [nsMacCursor cursorWithCursor:[NSCursor openHandCursor]
+                                      type:aCursor];
+    case eCursor_not_allowed:
+    case eCursor_no_drop: {
+      SEL cursorSelector = @selector(operationNotAllowedCursor);
+      return [nsMacCursor
+          cursorWithCursor:[NSCursor respondsToSelector:cursorSelector]
+                               ? [NSCursor performSelector:cursorSelector]
+                               : [NSCursor arrowCursor]
+                      type:aCursor];
+    }
+    // Resize Cursors:
+    // North
+    case eCursor_n_resize:
+      return [nsMacCursor cursorWithCursor:[NSCursor resizeUpCursor]
+                                      type:aCursor];
+    // North East
+    case eCursor_ne_resize:
+      return [nsMacCursor cursorWithImageNamed:@"sizeNE"
+                                       hotSpot:NSMakePoint(12, 11)
+                                          type:aCursor];
+    // East
+    case eCursor_e_resize:
+      return [nsMacCursor cursorWithCursor:[NSCursor resizeRightCursor]
+                                      type:aCursor];
+    // South East
+    case eCursor_se_resize:
+      return [nsMacCursor cursorWithImageNamed:@"sizeSE"
+                                       hotSpot:NSMakePoint(12, 12)
+                                          type:aCursor];
+    // South
+    case eCursor_s_resize:
+      return [nsMacCursor cursorWithCursor:[NSCursor resizeDownCursor]
+                                      type:aCursor];
+    // South West
+    case eCursor_sw_resize:
+      return [nsMacCursor cursorWithImageNamed:@"sizeSW"
+                                       hotSpot:NSMakePoint(10, 12)
+                                          type:aCursor];
+    // West
+    case eCursor_w_resize:
+      return [nsMacCursor cursorWithCursor:[NSCursor resizeLeftCursor]
+                                      type:aCursor];
+    // North West
+    case eCursor_nw_resize:
+      return [nsMacCursor cursorWithImageNamed:@"sizeNW"
+                                       hotSpot:NSMakePoint(11, 11)
+                                          type:aCursor];
+    // North & South
+    case eCursor_ns_resize:
+      return [nsMacCursor cursorWithCursor:[NSCursor resizeUpDownCursor]
+                                      type:aCursor];
+    // East & West
+    case eCursor_ew_resize:
+      return [nsMacCursor cursorWithCursor:[NSCursor resizeLeftRightCursor]
+                                      type:aCursor];
+    // North East & South West
+    case eCursor_nesw_resize:
+      return [nsMacCursor cursorWithImageNamed:@"sizeNESW"
+                                       hotSpot:NSMakePoint(12, 12)
+                                          type:aCursor];
+    // North West & South East
+    case eCursor_nwse_resize:
+      return [nsMacCursor cursorWithImageNamed:@"sizeNWSE"
+                                       hotSpot:NSMakePoint(12, 12)
+                                          type:aCursor];
+    // Column Resize
+    case eCursor_col_resize:
+      return [nsMacCursor cursorWithImageNamed:@"colResize"
+                                       hotSpot:NSMakePoint(12, 12)
+                                          type:aCursor];
+    // Row Resize
+    case eCursor_row_resize:
+      return [nsMacCursor cursorWithImageNamed:@"rowResize"
+                                       hotSpot:NSMakePoint(12, 12)
+                                          type:aCursor];
+    default:
+      return [nsMacCursor cursorWithCursor:[NSCursor arrowCursor] type:aCursor];
+  }
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (id)init {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if ((self = [super init])) {
+    mCursors = [[NSMutableDictionary alloc] initWithCapacity:25];
+  }
+  return self;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (nsresult)setNonCustomCursor:(const nsIWidget::Cursor&)aCursor {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  [self setMacCursor:[self getCursor:aCursor.mDefaultCursor]];
+
+  sCurrentCursor = aCursor;
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+- (nsresult)setMacCursor:(nsMacCursor*)aMacCursor {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  nsCursor oldType = [mCurrentMacCursor type];
+  nsCursor newType = [aMacCursor type];
+  if (oldType != newType) {
+    if (newType == eCursor_none) {
+      [NSCursor hide];
+    } else if (oldType == eCursor_none) {
+      [NSCursor unhide];
+    }
+  }
+
+  if (mCurrentMacCursor != aMacCursor || ![mCurrentMacCursor isSet]) {
+    [aMacCursor retain];
+    [mCurrentMacCursor unset];
+    [aMacCursor set];
+    [mCurrentMacCursor release];
+    mCurrentMacCursor = aMacCursor;
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+- (nsresult)setCustomCursor:(const nsIWidget::Cursor&)aCursor
+          widgetScaleFactor:(CGFloat)scaleFactor
+                forceUpdate:(bool)aForceUpdate {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // As the user moves the mouse, this gets called repeatedly with the same
+  // aCursorImage
+  if (!aForceUpdate && sCurrentCursor == aCursor &&
+      sCurrentCursorScaleFactor == scaleFactor && mCurrentMacCursor) {
+    // Native dragging can unset our cursor apparently (see bug 1739352).
+    if (MOZ_UNLIKELY(![mCurrentMacCursor isSet])) {
+      [mCurrentMacCursor set];
+    }
+    return NS_OK;
+  }
+
+  sCurrentCursor = aCursor;
+  sCurrentCursorScaleFactor = scaleFactor;
+
+  if (!aCursor.IsCustom()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsIntSize size = nsIWidget::CustomCursorSize(aCursor);
+  // prevent DoS attacks
+  if (size.width > 128 || size.height > 128) {
+    return NS_ERROR_FAILURE;
+  }
+
+  NSImage* cursorImage;
+  nsresult rv = nsCocoaUtils::CreateNSImageFromImageContainer(
+      aCursor.mContainer, imgIContainer::FRAME_FIRST, nullptr, nullptr,
+      &cursorImage, scaleFactor);
+  if (NS_FAILED(rv) || !cursorImage) {
+    return NS_ERROR_FAILURE;
+  }
+
+  {
+    NSSize cocoaSize = NSMakeSize(size.width, size.height);
+    [cursorImage setSize:cocoaSize];
+    [[[cursorImage representations] objectAtIndex:0] setSize:cocoaSize];
+  }
+
+  // if the hotspot is nonsensical, make it 0,0
+  uint32_t hotspotX =
+      aCursor.mHotspotX > (uint32_t(size.width) - 1) ? 0 : aCursor.mHotspotX;
+  uint32_t hotspotY =
+      aCursor.mHotspotY > (uint32_t(size.height) - 1) ? 0 : aCursor.mHotspotY;
+  NSPoint hotSpot = ::NSMakePoint(hotspotX, hotspotY);
+  [self setMacCursor:[nsMacCursor cursorWithCursor:[[NSCursor alloc]
+                                                       initWithImage:cursorImage
+                                                             hotSpot:hotSpot]
+                                              type:kCustomCursor]];
+  [cursorImage release];
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+- (nsMacCursor*)getCursor:(enum nsCursor)aCursor {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  nsMacCursor* result =
+      [mCursors objectForKey:[NSNumber numberWithInt:aCursor]];
+  if (!result) {
+    result = [nsCursorManager createCursor:aCursor];
+    [mCursors setObject:result forKey:[NSNumber numberWithInt:aCursor]];
+  }
+  return result;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (void)dealloc {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [mCurrentMacCursor unset];
+  [mCurrentMacCursor release];
+  [mCursors release];
+  sCurrentCursor = {};
+  [super dealloc];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+@end
diff --git a/widget/cocoa/nsDeviceContextSpecX.h b/widget/cocoa/nsDeviceContextSpecX.h
new file mode 100644
index 0000000000..a5a5bbb9d9
--- /dev/null
+++ b/widget/cocoa/nsDeviceContextSpecX.h
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsDeviceContextSpecX_h_
+#define nsDeviceContextSpecX_h_
+
+#include "nsIDeviceContextSpec.h"
+#include "nsIPrinter.h"
+#include "nsIPrinterList.h"
+
+#include "nsCOMPtr.h"
+
+#include "mozilla/gfx/PrintPromise.h"
+
+#include <ApplicationServices/ApplicationServices.h>
+
+class nsDeviceContextSpecX : public nsIDeviceContextSpec {
+ public:
+  NS_DECL_ISUPPORTS
+
+  nsDeviceContextSpecX();
+
+  NS_IMETHOD Init(nsIPrintSettings* aPS, bool aIsPrintPreview) override;
+  already_AddRefed<PrintTarget> MakePrintTarget() final;
+  NS_IMETHOD BeginDocument(const nsAString& aTitle,
+                           const nsAString& aPrintToFileName,
+                           int32_t aStartPage, int32_t aEndPage) override;
+  RefPtr<mozilla::gfx::PrintEndDocumentPromise> EndDocument() override;
+  NS_IMETHOD BeginPage(const IntSize& aSizeInPoints) override { return NS_OK; };
+  NS_IMETHOD EndPage() override { return NS_OK; };
+
+  void GetPaperRect(double* aTop, double* aLeft, double* aBottom,
+                    double* aRight);
+
+ protected:
+  virtual ~nsDeviceContextSpecX();
+
+ protected:
+  PMPrintSession mPrintSession = nullptr;
+  PMPageFormat mPageFormat = nullptr;
+  PMPrintSettings mPMPrintSettings = nullptr;
+  nsCOMPtr<nsIOutputStream> mOutputStream;  // Output stream from settings.
+#ifdef MOZ_ENABLE_SKIA_PDF
+  // file "print" output generated if printing via PDF
+  nsCOMPtr<nsIFile> mTempFile;
+#endif
+ private:
+  nsresult DoEndDocument();
+};
+
+#endif  // nsDeviceContextSpecX_h_
diff --git a/widget/cocoa/nsDeviceContextSpecX.mm b/widget/cocoa/nsDeviceContextSpecX.mm
new file mode 100644
index 0000000000..9bb8449b70
--- /dev/null
+++ b/widget/cocoa/nsDeviceContextSpecX.mm
@@ -0,0 +1,318 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsDeviceContextSpecX.h"
+
+#import <Cocoa/Cocoa.h>
+#include "mozilla/gfx/PrintPromise.h"
+#include <CoreFoundation/CoreFoundation.h>
+#include <unistd.h>
+
+#ifdef MOZ_ENABLE_SKIA_PDF
+#  include "mozilla/gfx/PrintTargetSkPDF.h"
+#endif
+#include "mozilla/gfx/PrintTargetCG.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/Telemetry.h"
+
+#include "AppleUtils.h"
+#include "nsCocoaUtils.h"
+#include "nsCRT.h"
+#include "nsCUPSShim.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsILocalFileMac.h"
+#include "nsIOutputStream.h"
+#include "nsPaper.h"
+#include "nsPrinterListCUPS.h"
+#include "nsPrintSettingsX.h"
+#include "nsQueryObject.h"
+#include "prenv.h"
+
+// This must be the last include:
+#include "nsObjCExceptions.h"
+
+using namespace mozilla;
+using mozilla::gfx::IntSize;
+using mozilla::gfx::PrintEndDocumentPromise;
+using mozilla::gfx::PrintTarget;
+using mozilla::gfx::PrintTargetCG;
+#ifdef MOZ_ENABLE_SKIA_PDF
+using mozilla::gfx::PrintTargetSkPDF;
+#endif
+
+//----------------------------------------------------------------------
+// nsDeviceContentSpecX
+
+nsDeviceContextSpecX::nsDeviceContextSpecX() = default;
+
+nsDeviceContextSpecX::~nsDeviceContextSpecX() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mPrintSession) {
+    ::PMRelease(mPrintSession);
+  }
+  if (mPageFormat) {
+    ::PMRelease(mPageFormat);
+  }
+  if (mPMPrintSettings) {
+    ::PMRelease(mPMPrintSettings);
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+NS_IMPL_ISUPPORTS(nsDeviceContextSpecX, nsIDeviceContextSpec)
+
+NS_IMETHODIMP nsDeviceContextSpecX::Init(nsIPrintSettings* aPS,
+                                         bool aIsPrintPreview) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  RefPtr<nsPrintSettingsX> settings(do_QueryObject(aPS));
+  if (!settings) {
+    return NS_ERROR_NO_INTERFACE;
+  }
+  // Note: unlike other platforms, we don't set our base class's mPrintSettings
+  // here since we don't need it currently (we do set mPMPrintSettings below).
+
+  NSPrintInfo* printInfo = settings->CreateOrCopyPrintInfo();
+  if (!printInfo) {
+    return NS_ERROR_FAILURE;
+  }
+  if (aPS->GetOutputDestination() ==
+      nsIPrintSettings::kOutputDestinationStream) {
+    aPS->GetOutputStream(getter_AddRefs(mOutputStream));
+    if (!mOutputStream) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+  mPrintSession = static_cast<PMPrintSession>([printInfo PMPrintSession]);
+  mPageFormat = static_cast<PMPageFormat>([printInfo PMPageFormat]);
+  mPMPrintSettings = static_cast<PMPrintSettings>([printInfo PMPrintSettings]);
+  MOZ_ASSERT(mPrintSession && mPageFormat && mPMPrintSettings);
+  ::PMRetain(mPrintSession);
+  ::PMRetain(mPageFormat);
+  ::PMRetain(mPMPrintSettings);
+  [printInfo release];
+
+#ifdef MOZ_ENABLE_SKIA_PDF
+  nsAutoString printViaPdf;
+  mozilla::Preferences::GetString("print.print_via_pdf_encoder", printViaPdf);
+  if (printViaPdf.EqualsLiteral("skia-pdf")) {
+    // Annoyingly, PMPrinterPrintWithFile does not pay attention to the
+    // kPMDestination* value set in the PMPrintSession; it always sends the PDF
+    // to the specified printer.  This means that if we create the PDF using
+    // SkPDF then we need to manually handle user actions like "Open PDF in
+    // Preview" and "Save as PDF...".
+    // TODO: Currently we do not support using SkPDF for kPMDestinationFax or
+    // kPMDestinationProcessPDF ("Add PDF to iBooks, etc.), and we only support
+    // it for kPMDestinationFile if the destination file is a PDF.
+    // XXX Could PMWorkflowSubmitPDFWithSettings/PMPrinterPrintWithProvider
+    // help?
+    OSStatus status = noErr;
+    PMDestinationType destination;
+    status = ::PMSessionGetDestinationType(mPrintSession, mPMPrintSettings,
+                                           &destination);
+    if (status == noErr) {
+      if (destination == kPMDestinationPrinter ||
+          destination == kPMDestinationPreview) {
+        mPrintViaSkPDF = true;
+      } else if (destination == kPMDestinationFile) {
+        AutoCFRelease<CFURLRef> destURL(nullptr);
+        status = ::PMSessionCopyDestinationLocation(
+            mPrintSession, mPMPrintSettings, destURL.receive());
+        if (status == noErr) {
+          AutoCFRelease<CFStringRef> destPathRef =
+              CFURLCopyFileSystemPath(destURL, kCFURLPOSIXPathStyle);
+          NSString* destPath = (NSString*)CFStringRef(destPathRef);
+          NSString* destPathExt = [destPath pathExtension];
+          if ([destPathExt isEqualToString:@"pdf"]) {
+            mPrintViaSkPDF = true;
+          }
+        }
+      }
+    }
+  }
+#endif
+
+  int16_t outputFormat = aPS->GetOutputFormat();
+
+  if (outputFormat == nsIPrintSettings::kOutputFormatPDF) {
+    // We don't actually currently support/use kOutputFormatPDF on mac, but
+    // this is for completeness in case we add that (we probably need to in
+    // order to support adding links into saved PDFs, for example).
+    Telemetry::ScalarAdd(Telemetry::ScalarID::PRINTING_TARGET_TYPE,
+                         u"pdf_file"_ns, 1);
+  } else {
+    PMDestinationType destination;
+    OSStatus status = ::PMSessionGetDestinationType(
+        mPrintSession, mPMPrintSettings, &destination);
+    if (status == noErr && (destination == kPMDestinationFile ||
+                            destination == kPMDestinationPreview ||
+                            destination == kPMDestinationProcessPDF)) {
+      Telemetry::ScalarAdd(Telemetry::ScalarID::PRINTING_TARGET_TYPE,
+                           u"pdf_file"_ns, 1);
+    } else {
+      Telemetry::ScalarAdd(Telemetry::ScalarID::PRINTING_TARGET_TYPE,
+                           u"unknown"_ns, 1);
+    }
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP nsDeviceContextSpecX::BeginDocument(
+    const nsAString& aTitle, const nsAString& aPrintToFileName,
+    int32_t aStartPage, int32_t aEndPage) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+RefPtr<PrintEndDocumentPromise> nsDeviceContextSpecX::EndDocument() {
+  return nsIDeviceContextSpec::EndDocumentPromiseFromResult(DoEndDocument(),
+                                                            __func__);
+}
+
+nsresult nsDeviceContextSpecX::DoEndDocument() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+#ifdef MOZ_ENABLE_SKIA_PDF
+  if (mPrintViaSkPDF) {
+    OSStatus status = noErr;
+
+    nsCOMPtr<nsILocalFileMac> tmpPDFFile = do_QueryInterface(mTempFile);
+    if (!tmpPDFFile) {
+      return NS_ERROR_FAILURE;
+    }
+    AutoCFRelease<CFURLRef> pdfURL(nullptr);
+    // Note that the caller is responsible to release pdfURL according to
+    // nsILocalFileMac.idl, even though we didn't follow the Core Foundation
+    // naming conventions here (the method should've been called CopyCFURL).
+    nsresult rv = tmpPDFFile->GetCFURL(pdfURL.receive());
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    PMDestinationType destination;
+    status = ::PMSessionGetDestinationType(mPrintSession, mPMPrintSettings,
+                                           &destination);
+
+    switch (destination) {
+      case kPMDestinationPrinter: {
+        PMPrinter currentPrinter = NULL;
+        status = ::PMSessionGetCurrentPrinter(mPrintSession, &currentPrinter);
+        if (status != noErr) {
+          return NS_ERROR_FAILURE;
+        }
+        CFStringRef mimeType = CFSTR("application/pdf");
+        status = ::PMPrinterPrintWithFile(currentPrinter, mPMPrintSettings,
+                                          mPageFormat, mimeType, pdfURL);
+        break;
+      }
+      case kPMDestinationPreview: {
+        // XXXjwatt Or should we use CocoaFileUtils::RevealFileInFinder(pdfURL);
+        AutoCFRelease<CFStringRef> pdfPath =
+            CFURLCopyFileSystemPath(pdfURL, kCFURLPOSIXPathStyle);
+        NSString* path = (NSString*)CFStringRef(pdfPath);
+        NSWorkspace* ws = [NSWorkspace sharedWorkspace];
+        [ws openFile:path];
+        break;
+      }
+      case kPMDestinationFile: {
+        AutoCFRelease<CFURLRef> destURL(nullptr);
+        status = ::PMSessionCopyDestinationLocation(
+            mPrintSession, mPMPrintSettings, destURL.receive());
+        if (status == noErr) {
+          AutoCFRelease<CFStringRef> sourcePathRef =
+              CFURLCopyFileSystemPath(pdfURL, kCFURLPOSIXPathStyle);
+          NSString* sourcePath = (NSString*)CFStringRef(sourcePathRef);
+#  ifdef DEBUG
+          AutoCFRelease<CFStringRef> destPathRef =
+              CFURLCopyFileSystemPath(destURL, kCFURLPOSIXPathStyle);
+          NSString* destPath = (NSString*)CFStringRef(destPathRef);
+          NSString* destPathExt = [destPath pathExtension];
+          MOZ_ASSERT([destPathExt isEqualToString:@"pdf"],
+                     "nsDeviceContextSpecX::Init only allows '.pdf' for now");
+          // We could use /usr/sbin/cupsfilter to convert the PDF to PS, but
+          // currently we don't.
+#  endif
+          NSFileManager* fileManager = [NSFileManager defaultManager];
+          if ([fileManager fileExistsAtPath:sourcePath]) {
+            NSURL* src = static_cast<NSURL*>(CFURLRef(pdfURL));
+            NSURL* dest = static_cast<NSURL*>(CFURLRef(destURL));
+            bool ok = [fileManager
+                replaceItemAtURL:dest
+                   withItemAtURL:src
+                  backupItemName:nil
+                         options:
+                             NSFileManagerItemReplacementUsingNewMetadataOnly
+                resultingItemURL:nil
+                           error:nil];
+            if (!ok) {
+              return NS_ERROR_FAILURE;
+            }
+          }
+        }
+        break;
+      }
+      default:
+        MOZ_ASSERT_UNREACHABLE("nsDeviceContextSpecX::Init doesn't set "
+                               "mPrintViaSkPDF for other values");
+    }
+
+    return (status == noErr) ? NS_OK : NS_ERROR_FAILURE;
+  }
+#endif
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void nsDeviceContextSpecX::GetPaperRect(double* aTop, double* aLeft,
+                                        double* aBottom, double* aRight) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  PMRect paperRect;
+  ::PMGetAdjustedPaperRect(mPageFormat, &paperRect);
+
+  *aTop = paperRect.top;
+  *aLeft = paperRect.left;
+  *aBottom = paperRect.bottom;
+  *aRight = paperRect.right;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+already_AddRefed<PrintTarget> nsDeviceContextSpecX::MakePrintTarget() {
+  double top, left, bottom, right;
+  GetPaperRect(&top, &left, &bottom, &right);
+  const double width = right - left;
+  const double height = bottom - top;
+  IntSize size = IntSize::Ceil(width, height);
+
+#ifdef MOZ_ENABLE_SKIA_PDF
+  if (mPrintViaSkPDF) {
+    // TODO: Add support for stream printing via SkPDF if we enable that again.
+    nsresult rv =
+        NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(mTempFile));
+    NS_ENSURE_SUCCESS(rv, nullptr);
+    nsAutoCString tempPath("tmp-printing.pdf");
+    mTempFile->AppendNative(tempPath);
+    rv = mTempFile->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0600);
+    NS_ENSURE_SUCCESS(rv, nullptr);
+    mTempFile->GetNativePath(tempPath);
+    auto stream = MakeUnique<SkFILEWStream>(tempPath.get());
+    return PrintTargetSkPDF::CreateOrNull(std::move(stream), size);
+  }
+#endif
+
+  return PrintTargetCG::CreateOrNull(mOutputStream, mPrintSession, mPageFormat,
+                                     mPMPrintSettings, size);
+}
diff --git a/widget/cocoa/nsDragService.h b/widget/cocoa/nsDragService.h
new file mode 100644
index 0000000000..b175b93247
--- /dev/null
+++ b/widget/cocoa/nsDragService.h
@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsDragService_h_
+#define nsDragService_h_
+
+#include "nsBaseDragService.h"
+#include "nsChildView.h"
+
+#include <Cocoa/Cocoa.h>
+
+class nsDragService : public nsBaseDragService {
+ public:
+  nsDragService();
+
+  // nsBaseDragService
+  MOZ_CAN_RUN_SCRIPT virtual nsresult InvokeDragSessionImpl(
+      nsIArray* anArrayTransferables,
+      const mozilla::Maybe<mozilla::CSSIntRegion>& aRegion,
+      uint32_t aActionType) override;
+  // nsIDragService
+  MOZ_CAN_RUN_SCRIPT NS_IMETHOD EndDragSession(bool aDoneDrag,
+                                               uint32_t aKeyModifiers) override;
+  NS_IMETHOD UpdateDragImage(nsINode* aImage, int32_t aImageX,
+                             int32_t aImageY) override;
+
+  // nsIDragSession
+  NS_IMETHOD GetData(nsITransferable* aTransferable,
+                     uint32_t aItemIndex) override;
+  NS_IMETHOD IsDataFlavorSupported(const char* aDataFlavor,
+                                   bool* _retval) override;
+  NS_IMETHOD GetNumDropItems(uint32_t* aNumItems) override;
+
+  void DragMovedWithView(NSDraggingSession* aSession, NSPoint aPoint);
+
+ protected:
+  virtual ~nsDragService();
+
+ private:
+  // Creates and returns the drag image for a drag. aImagePoint will be set to
+  // the origin of the drag relative to mNativeDragView.
+  NSImage* ConstructDragImage(
+      nsINode* aDOMNode, const mozilla::Maybe<mozilla::CSSIntRegion>& aRegion,
+      NSPoint* aImagePoint);
+
+  // Creates and returns the drag image for a drag. aPoint should be the origin
+  // of the drag, for example the mouse coordinate of the mousedown event.
+  // aDragRect will be set the area of the drag relative to this.
+  NSImage* ConstructDragImage(
+      nsINode* aDOMNode, const mozilla::Maybe<mozilla::CSSIntRegion>& aRegion,
+      mozilla::CSSIntPoint aPoint, mozilla::LayoutDeviceIntRect* aDragRect);
+
+  nsCOMPtr<nsIArray> mDataItems;  // only valid for a drag started within gecko
+  ChildView* mNativeDragView;
+  NSEvent* mNativeDragEvent;
+
+  bool mDragImageChanged;
+};
+
+#endif  // nsDragService_h_
diff --git a/widget/cocoa/nsDragService.mm b/widget/cocoa/nsDragService.mm
new file mode 100644
index 0000000000..26bb834a89
--- /dev/null
+++ b/widget/cocoa/nsDragService.mm
@@ -0,0 +1,507 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Logging.h"
+
+#include "gfxContext.h"
+#include "nsArrayUtils.h"
+#include "nsDragService.h"
+#include "nsArrayUtils.h"
+#include "nsObjCExceptions.h"
+#include "nsITransferable.h"
+#include "nsString.h"
+#include "nsClipboard.h"
+#include "nsXPCOM.h"
+#include "nsCOMPtr.h"
+#include "nsPrimitiveHelpers.h"
+#include "nsLinebreakConverter.h"
+#include "nsINode.h"
+#include "nsRect.h"
+#include "nsPoint.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/DocumentInlines.h"
+#include "nsIContent.h"
+#include "nsView.h"
+#include "nsCocoaUtils.h"
+#include "mozilla/gfx/2D.h"
+#include "gfxPlatform.h"
+#include "nsDeviceContext.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+
+extern mozilla::LazyLogModule sCocoaLog;
+
+extern NSPasteboard* globalDragPboard;
+extern ChildView* gLastDragView;
+extern NSEvent* gLastDragMouseDownEvent;
+extern bool gUserCancelledDrag;
+
+// This global makes the transferable array available to Cocoa's promised
+// file destination callback.
+mozilla::StaticRefPtr<nsIArray> gDraggedTransferables;
+
+nsDragService::nsDragService()
+    : mNativeDragView(nil), mNativeDragEvent(nil), mDragImageChanged(false) {}
+
+nsDragService::~nsDragService() {}
+
+NSImage* nsDragService::ConstructDragImage(nsINode* aDOMNode,
+                                           const Maybe<CSSIntRegion>& aRegion,
+                                           NSPoint* aDragPoint) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  CGFloat scaleFactor = nsCocoaUtils::GetBackingScaleFactor(mNativeDragView);
+
+  LayoutDeviceIntRect dragRect(0, 0, 20, 20);
+  NSImage* image =
+      ConstructDragImage(mSourceNode, aRegion, mScreenPosition, &dragRect);
+  if (!image) {
+    // if no image was returned, just draw a rectangle
+    NSSize size;
+    size.width =
+        nsCocoaUtils::DevPixelsToCocoaPoints(dragRect.width, scaleFactor);
+    size.height =
+        nsCocoaUtils::DevPixelsToCocoaPoints(dragRect.height, scaleFactor);
+    image = [NSImage imageWithSize:size
+                           flipped:YES
+                    drawingHandler:^BOOL(NSRect dstRect) {
+                      [[NSColor grayColor] set];
+                      NSBezierPath* path =
+                          [NSBezierPath bezierPathWithRect:dstRect];
+                      [path setLineWidth:2.0];
+                      [path stroke];
+                      return YES;
+                    }];
+  }
+
+  LayoutDeviceIntPoint pt(dragRect.x, dragRect.YMost());
+  NSPoint point = nsCocoaUtils::DevPixelsToCocoaPoints(pt, scaleFactor);
+  point.y = nsCocoaUtils::FlippedScreenY(point.y);
+
+  point = nsCocoaUtils::ConvertPointFromScreen([mNativeDragView window], point);
+  *aDragPoint = [mNativeDragView convertPoint:point fromView:nil];
+
+  return image;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+NSImage* nsDragService::ConstructDragImage(nsINode* aDOMNode,
+                                           const Maybe<CSSIntRegion>& aRegion,
+                                           CSSIntPoint aPoint,
+                                           LayoutDeviceIntRect* aDragRect) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  CGFloat scaleFactor = nsCocoaUtils::GetBackingScaleFactor(mNativeDragView);
+
+  RefPtr<SourceSurface> surface;
+  nsPresContext* pc;
+  nsresult rv = DrawDrag(aDOMNode, aRegion, aPoint, aDragRect, &surface, &pc);
+  if (pc && (!aDragRect->width || !aDragRect->height)) {
+    // just use some suitable defaults
+    int32_t size = nsCocoaUtils::CocoaPointsToDevPixels(20, scaleFactor);
+    aDragRect->SetRect(pc->CSSPixelsToDevPixels(aPoint.x),
+                       pc->CSSPixelsToDevPixels(aPoint.y), size, size);
+  }
+
+  if (NS_FAILED(rv) || !surface) return nil;
+
+  uint32_t width = aDragRect->width;
+  uint32_t height = aDragRect->height;
+
+  RefPtr<DataSourceSurface> dataSurface = Factory::CreateDataSourceSurface(
+      IntSize(width, height), SurfaceFormat::B8G8R8A8);
+  DataSourceSurface::MappedSurface map;
+  if (!dataSurface->Map(DataSourceSurface::MapType::READ_WRITE, &map)) {
+    return nil;
+  }
+
+  RefPtr<DrawTarget> dt = Factory::CreateDrawTargetForData(
+      BackendType::CAIRO, map.mData, dataSurface->GetSize(), map.mStride,
+      dataSurface->GetFormat());
+  if (!dt) {
+    dataSurface->Unmap();
+    return nil;
+  }
+
+  dt->FillRect(gfx::Rect(0, 0, width, height),
+               SurfacePattern(surface, ExtendMode::CLAMP),
+               DrawOptions(1.0f, CompositionOp::OP_SOURCE));
+
+  NSBitmapImageRep* imageRep =
+      [[NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL
+                                              pixelsWide:width
+                                              pixelsHigh:height
+                                           bitsPerSample:8
+                                         samplesPerPixel:4
+                                                hasAlpha:YES
+                                                isPlanar:NO
+                                          colorSpaceName:NSDeviceRGBColorSpace
+                                             bytesPerRow:width * 4
+                                            bitsPerPixel:32];
+
+  uint8_t* dest = [imageRep bitmapData];
+  for (uint32_t i = 0; i < height; ++i) {
+    uint8_t* src = map.mData + i * map.mStride;
+    for (uint32_t j = 0; j < width; ++j) {
+      // Reduce transparency overall by multipying by a factor. Remember, Alpha
+      // is premultipled here. Also, Quartz likes RGBA, so do that translation
+      // as well.
+#ifdef IS_BIG_ENDIAN
+      dest[0] = uint8_t(src[1] * DRAG_TRANSLUCENCY);
+      dest[1] = uint8_t(src[2] * DRAG_TRANSLUCENCY);
+      dest[2] = uint8_t(src[3] * DRAG_TRANSLUCENCY);
+      dest[3] = uint8_t(src[0] * DRAG_TRANSLUCENCY);
+#else
+      dest[0] = uint8_t(src[2] * DRAG_TRANSLUCENCY);
+      dest[1] = uint8_t(src[1] * DRAG_TRANSLUCENCY);
+      dest[2] = uint8_t(src[0] * DRAG_TRANSLUCENCY);
+      dest[3] = uint8_t(src[3] * DRAG_TRANSLUCENCY);
+#endif
+      src += 4;
+      dest += 4;
+    }
+  }
+  dataSurface->Unmap();
+
+  NSImage* image = [[NSImage alloc]
+      initWithSize:NSMakeSize(width / scaleFactor, height / scaleFactor)];
+  [image addRepresentation:imageRep];
+  [imageRep release];
+
+  return [image autorelease];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+nsresult nsDragService::InvokeDragSessionImpl(
+    nsIArray* aTransferableArray, const Maybe<CSSIntRegion>& aRegion,
+    uint32_t aActionType) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+#ifdef NIGHTLY_BUILD
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+#endif
+
+  if (!gLastDragView) {
+    // gLastDragView is non-null between -[ChildView mouseDown:] and -[ChildView
+    // mouseUp:]. If we get here with gLastDragView being null, that means that
+    // the mouse button has already been released. In that case we need to abort
+    // the drag because the OS won't know where to drop whatever's being
+    // dragged, and we might end up with a stuck drag & drop session.
+    return NS_ERROR_FAILURE;
+  }
+
+  mDataItems = aTransferableArray;
+
+  // Save the transferables away in case a promised file callback is invoked.
+  gDraggedTransferables = aTransferableArray;
+
+  // We need to retain the view and the event during the drag in case either
+  // gets destroyed.
+  mNativeDragView = [gLastDragView retain];
+  mNativeDragEvent = [gLastDragMouseDownEvent retain];
+
+  gUserCancelledDrag = false;
+
+  NSPasteboardItem* pbItem = [NSPasteboardItem new];
+  NSMutableArray* types = [NSMutableArray arrayWithCapacity:5];
+
+  if (gDraggedTransferables) {
+    uint32_t count = 0;
+    gDraggedTransferables->GetLength(&count);
+
+    for (uint32_t j = 0; j < count; j++) {
+      nsCOMPtr<nsITransferable> currentTransferable =
+          do_QueryElementAt(aTransferableArray, j);
+      if (!currentTransferable) {
+        return NS_ERROR_FAILURE;
+      }
+
+      // Transform the transferable to an NSDictionary
+      NSDictionary* pasteboardOutputDict =
+          nsClipboard::PasteboardDictFromTransferable(currentTransferable);
+      if (!pasteboardOutputDict) {
+        return NS_ERROR_FAILURE;
+      }
+
+      // write everything out to the general pasteboard
+      [types addObjectsFromArray:[pasteboardOutputDict allKeys]];
+      // Gecko is initiating this drag so we always want its own views to
+      // consider it. Add our wildcard type to the pasteboard to accomplish
+      // this.
+      [types addObject:[UTIHelper stringFromPboardType:kMozWildcardPboardType]];
+    }
+  }
+  [pbItem setDataProvider:mNativeDragView forTypes:types];
+
+  NSPoint draggingPoint;
+  NSImage* image = ConstructDragImage(mSourceNode, aRegion, &draggingPoint);
+
+  NSRect localDragRect = image.alignmentRect;
+  localDragRect.origin.x = draggingPoint.x;
+  localDragRect.origin.y = draggingPoint.y - localDragRect.size.height;
+
+  NSDraggingItem* dragItem =
+      [[NSDraggingItem alloc] initWithPasteboardWriter:pbItem];
+  [pbItem release];
+  [dragItem setDraggingFrame:localDragRect contents:image];
+
+  nsBaseDragService::StartDragSession();
+  nsBaseDragService::OpenDragPopup();
+
+  NSDraggingSession* draggingSession = [mNativeDragView
+      beginDraggingSessionWithItems:[NSArray
+                                        arrayWithObject:[dragItem autorelease]]
+                              event:mNativeDragEvent
+                             source:mNativeDragView];
+  draggingSession.animatesToStartingPositionsOnCancelOrFail =
+      !mDataTransfer || mDataTransfer->MozShowFailAnimation();
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsDragService::GetData(nsITransferable* aTransferable, uint32_t aItemIndex) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!aTransferable) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // get flavor list that includes all acceptable flavors (including ones
+  // obtained through conversion)
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanImport(flavors);
+  if (NS_FAILED(rv)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // if this drag originated within Mozilla we should just use the cached data
+  // from when the drag started if possible
+  if (mDataItems) {
+    nsCOMPtr<nsITransferable> currentTransferable =
+        do_QueryElementAt(mDataItems, aItemIndex);
+    if (currentTransferable) {
+      for (uint32_t i = 0; i < flavors.Length(); i++) {
+        nsCString& flavorStr = flavors[i];
+
+        nsCOMPtr<nsISupports> dataSupports;
+        rv = currentTransferable->GetTransferData(flavorStr.get(),
+                                                  getter_AddRefs(dataSupports));
+        if (NS_SUCCEEDED(rv)) {
+          aTransferable->SetTransferData(flavorStr.get(), dataSupports);
+          return NS_OK;  // maybe try to fill in more types? Is there a point?
+        }
+      }
+    }
+  }
+
+  NSArray* droppedItems = [globalDragPboard pasteboardItems];
+  if (!droppedItems) {
+    return NS_ERROR_FAILURE;
+  }
+
+  uint32_t itemCount = [droppedItems count];
+  if (aItemIndex >= itemCount) {
+    return NS_ERROR_FAILURE;
+  }
+
+  NSPasteboardItem* item = [droppedItems objectAtIndex:aItemIndex];
+  if (!item) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // now check the actual clipboard for data
+  for (uint32_t i = 0; i < flavors.Length(); i++) {
+    nsCocoaUtils::SetTransferDataForTypeFromPasteboardItem(aTransferable,
+                                                           flavors[i], item);
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsDragService::IsDataFlavorSupported(const char* aDataFlavor, bool* _retval) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  *_retval = false;
+
+  if (!globalDragPboard) return NS_ERROR_FAILURE;
+
+  nsDependentCString dataFlavor(aDataFlavor);
+
+  // first see if we have data for this in our cached transferable
+  if (mDataItems) {
+    uint32_t dataItemsCount;
+    mDataItems->GetLength(&dataItemsCount);
+    for (unsigned int i = 0; i < dataItemsCount; i++) {
+      nsCOMPtr<nsITransferable> currentTransferable =
+          do_QueryElementAt(mDataItems, i);
+      if (!currentTransferable) continue;
+
+      nsTArray<nsCString> flavors;
+      nsresult rv = currentTransferable->FlavorsTransferableCanImport(flavors);
+      if (NS_FAILED(rv)) continue;
+
+      for (uint32_t j = 0; j < flavors.Length(); j++) {
+        if (dataFlavor.Equals(flavors[j])) {
+          *_retval = true;
+          return NS_OK;
+        }
+      }
+    }
+  }
+
+  const NSString* type = nil;
+  bool allowFileURL = false;
+  if (dataFlavor.EqualsLiteral(kFileMime)) {
+    type = [UTIHelper stringFromPboardType:(NSString*)kUTTypeFileURL];
+    allowFileURL = true;
+  } else if (dataFlavor.EqualsLiteral(kTextMime)) {
+    type = [UTIHelper stringFromPboardType:NSPasteboardTypeString];
+  } else if (dataFlavor.EqualsLiteral(kHTMLMime)) {
+    type = [UTIHelper stringFromPboardType:NSPasteboardTypeHTML];
+  } else if (dataFlavor.EqualsLiteral(kURLMime) ||
+             dataFlavor.EqualsLiteral(kURLDataMime)) {
+    type = [UTIHelper stringFromPboardType:kPublicUrlPboardType];
+  } else if (dataFlavor.EqualsLiteral(kURLDescriptionMime)) {
+    type = [UTIHelper stringFromPboardType:kPublicUrlNamePboardType];
+  } else if (dataFlavor.EqualsLiteral(kRTFMime)) {
+    type = [UTIHelper stringFromPboardType:NSPasteboardTypeRTF];
+  } else if (dataFlavor.EqualsLiteral(kCustomTypesMime)) {
+    type = [UTIHelper stringFromPboardType:kMozCustomTypesPboardType];
+  }
+
+  NSString* availableType = [globalDragPboard
+      availableTypeFromArray:[NSArray arrayWithObjects:(id)type, nil]];
+  if (availableType &&
+      nsCocoaUtils::IsValidPasteboardType(availableType, allowFileURL)) {
+    *_retval = true;
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsDragService::GetNumDropItems(uint32_t* aNumItems) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  *aNumItems = 0;
+
+  // first check to see if we have a number of items cached
+  if (mDataItems) {
+    mDataItems->GetLength(aNumItems);
+    return NS_OK;
+  }
+
+  NSArray* droppedItems = [globalDragPboard pasteboardItems];
+  if (droppedItems) {
+    *aNumItems = [droppedItems count];
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsDragService::UpdateDragImage(nsINode* aImage, int32_t aImageX,
+                               int32_t aImageY) {
+  nsBaseDragService::UpdateDragImage(aImage, aImageX, aImageY);
+  mDragImageChanged = true;
+  return NS_OK;
+}
+
+void nsDragService::DragMovedWithView(NSDraggingSession* aSession,
+                                      NSPoint aPoint) {
+  aPoint.y = nsCocoaUtils::FlippedScreenY(aPoint.y);
+
+  // XXX It feels like we should be using the backing scale factor at aPoint
+  // rather than the initial drag view, but I've seen no ill effects of this.
+  CGFloat scaleFactor = nsCocoaUtils::GetBackingScaleFactor(mNativeDragView);
+  LayoutDeviceIntPoint devPoint =
+      nsCocoaUtils::CocoaPointsToDevPixels(aPoint, scaleFactor);
+
+  // If the image has changed, call enumerateDraggingItemsWithOptions to get
+  // the item being dragged and update its image.
+  if (mDragImageChanged && mNativeDragView) {
+    mDragImageChanged = false;
+
+    nsPresContext* pc = nullptr;
+    nsCOMPtr<nsIContent> content = do_QueryInterface(mImage);
+    if (content) {
+      pc = content->OwnerDoc()->GetPresContext();
+    }
+
+    if (pc) {
+      void (^changeImageBlock)(NSDraggingItem*, NSInteger, BOOL*) = ^(
+          NSDraggingItem* draggingItem, NSInteger idx, BOOL* stop) {
+        // We never add more than one item right now, but check just in case.
+        if (idx > 0) {
+          return;
+        }
+
+        nsPoint pt = LayoutDevicePixel::ToAppUnits(
+            devPoint, pc->DeviceContext()->AppUnitsPerDevPixel());
+        CSSIntPoint screenPoint =
+            CSSIntPoint(nsPresContext::AppUnitsToIntCSSPixels(pt.x),
+                        nsPresContext::AppUnitsToIntCSSPixels(pt.y));
+
+        // Create a new image; if one isn't returned don't change the current
+        // one.
+        LayoutDeviceIntRect newRect;
+        NSImage* image =
+            ConstructDragImage(mSourceNode, Nothing(), screenPoint, &newRect);
+        if (image) {
+          NSRect draggingRect =
+              nsCocoaUtils::GeckoRectToCocoaRectDevPix(newRect, scaleFactor);
+          [draggingItem setDraggingFrame:draggingRect contents:image];
+        }
+      };
+
+      [aSession
+          enumerateDraggingItemsWithOptions:NSDraggingItemEnumerationConcurrent
+                                    forView:nil
+                                    classes:[NSArray
+                                                arrayWithObject:
+                                                    [NSPasteboardItem class]]
+                              searchOptions:@{}
+                                 usingBlock:changeImageBlock];
+    }
+  }
+
+  DragMoved(devPoint.x, devPoint.y);
+}
+
+NS_IMETHODIMP
+nsDragService::EndDragSession(bool aDoneDrag, uint32_t aKeyModifiers) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (mNativeDragView) {
+    [mNativeDragView release];
+    mNativeDragView = nil;
+  }
+  if (mNativeDragEvent) {
+    [mNativeDragEvent release];
+    mNativeDragEvent = nil;
+  }
+
+  mUserCancelled = gUserCancelledDrag;
+
+  nsresult rv = nsBaseDragService::EndDragSession(aDoneDrag, aKeyModifiers);
+  mDataItems = nullptr;
+  return rv;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
diff --git a/widget/cocoa/nsFilePicker.h b/widget/cocoa/nsFilePicker.h
new file mode 100644
index 0000000000..a7ea5557c4
--- /dev/null
+++ b/widget/cocoa/nsFilePicker.h
@@ -0,0 +1,74 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsFilePicker_h_
+#define nsFilePicker_h_
+
+#include "nsBaseFilePicker.h"
+#include "nsString.h"
+#include "nsIFile.h"
+#include "nsCOMArray.h"
+#include "nsTArray.h"
+
+class nsILocalFileMac;
+@class NSArray;
+
+class nsFilePicker : public nsBaseFilePicker {
+ public:
+  nsFilePicker();
+  using nsIFilePicker::ResultCode;
+
+  NS_DECL_ISUPPORTS
+
+  // nsIFilePicker (less what's in nsBaseFilePicker)
+  NS_IMETHOD GetDefaultString(nsAString& aDefaultString) override;
+  NS_IMETHOD SetDefaultString(const nsAString& aDefaultString) override;
+  NS_IMETHOD GetDefaultExtension(nsAString& aDefaultExtension) override;
+  NS_IMETHOD GetFilterIndex(int32_t* aFilterIndex) override;
+  NS_IMETHOD SetFilterIndex(int32_t aFilterIndex) override;
+  NS_IMETHOD SetDefaultExtension(const nsAString& aDefaultExtension) override;
+  NS_IMETHOD GetFile(nsIFile** aFile) override;
+  NS_IMETHOD GetFileURL(nsIURI** aFileURL) override;
+  NS_IMETHOD GetFiles(nsISimpleEnumerator** aFiles) override;
+  NS_IMETHOD AppendFilter(const nsAString& aTitle,
+                          const nsAString& aFilter) override;
+
+  /**
+   * Returns the current filter list in the format used by Cocoa's NSSavePanel
+   * and NSOpenPanel.
+   * Returns nil if no filter currently apply.
+   */
+  NSArray* GetFilterList();
+
+ protected:
+  virtual ~nsFilePicker();
+
+  virtual void InitNative(nsIWidget* aParent, const nsAString& aTitle) override;
+  nsresult Show(ResultCode* _retval) override;
+
+  // actual implementations of get/put dialogs using NSOpenPanel & NSSavePanel
+  // aFile is an existing but unspecified file. These functions must specify it.
+  //
+  // will return |returnCancel| or |returnOK| as result.
+  ResultCode GetLocalFiles(bool inAllowMultiple, nsCOMArray<nsIFile>& outFiles);
+  ResultCode GetLocalFolder(nsIFile** outFile);
+  ResultCode PutLocalFile(nsIFile** outFile);
+
+  void SetDialogTitle(const nsString& inTitle, id aDialog);
+  NSString* PanelDefaultDirectory();
+  NSView* GetAccessoryView();
+
+  nsString mTitle;
+  nsCOMArray<nsIFile> mFiles;
+  nsString mDefaultFilename;
+
+  nsTArray<nsString> mFilters;
+  nsTArray<nsString> mTitles;
+
+  int32_t mSelectedTypeIndex;
+};
+
+#endif  // nsFilePicker_h_
diff --git a/widget/cocoa/nsFilePicker.mm b/widget/cocoa/nsFilePicker.mm
new file mode 100644
index 0000000000..31c64c5367
--- /dev/null
+++ b/widget/cocoa/nsFilePicker.mm
@@ -0,0 +1,679 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsFilePicker.h"
+#include "nsCOMPtr.h"
+#include "nsReadableUtils.h"
+#include "nsNetUtil.h"
+#include "nsIFile.h"
+#include "nsILocalFileMac.h"
+#include "nsArrayEnumerator.h"
+#include "nsIStringBundle.h"
+#include "nsCocoaUtils.h"
+#include "mozilla/Preferences.h"
+
+// This must be included last:
+#include "nsObjCExceptions.h"
+
+using namespace mozilla;
+
+const float kAccessoryViewPadding = 5;
+const int kSaveTypeControlTag = 1;
+
+static bool gCallSecretHiddenFileAPI = false;
+const char kShowHiddenFilesPref[] = "filepicker.showHiddenFiles";
+
+/**
+ * This class is an observer of NSPopUpButton selection change.
+ */
+@interface NSPopUpButtonObserver : NSObject {
+  NSPopUpButton* mPopUpButton;
+  NSOpenPanel* mOpenPanel;
+  nsFilePicker* mFilePicker;
+}
+- (void)setPopUpButton:(NSPopUpButton*)aPopUpButton;
+- (void)setOpenPanel:(NSOpenPanel*)aOpenPanel;
+- (void)setFilePicker:(nsFilePicker*)aFilePicker;
+- (void)menuChangedItem:(NSNotification*)aSender;
+@end
+
+NS_IMPL_ISUPPORTS(nsFilePicker, nsIFilePicker)
+
+// We never want to call the secret show hidden files API unless the pref
+// has been set. Once the pref has been set we always need to call it even
+// if it disappears so that we stop showing hidden files if a user deletes
+// the pref. If the secret API was used once and things worked out it should
+// continue working for subsequent calls so the user is at no more risk.
+static void SetShowHiddenFileState(NSSavePanel* panel) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  bool show = false;
+  if (NS_SUCCEEDED(Preferences::GetBool(kShowHiddenFilesPref, &show))) {
+    gCallSecretHiddenFileAPI = true;
+  }
+
+  if (gCallSecretHiddenFileAPI) {
+    // invoke a method to get a Cocoa-internal nav view
+    SEL navViewSelector = @selector(_navView);
+    NSMethodSignature* navViewSignature =
+        [panel methodSignatureForSelector:navViewSelector];
+    if (!navViewSignature) return;
+    NSInvocation* navViewInvocation =
+        [NSInvocation invocationWithMethodSignature:navViewSignature];
+    [navViewInvocation setSelector:navViewSelector];
+    [navViewInvocation setTarget:panel];
+    [navViewInvocation invoke];
+
+    // get the returned nav view
+    id navView = nil;
+    [navViewInvocation getReturnValue:&navView];
+
+    // invoke the secret show hidden file state method on the nav view
+    SEL showHiddenFilesSelector = @selector(setShowsHiddenFiles:);
+    NSMethodSignature* showHiddenFilesSignature =
+        [navView methodSignatureForSelector:showHiddenFilesSelector];
+    if (!showHiddenFilesSignature) return;
+    NSInvocation* showHiddenFilesInvocation =
+        [NSInvocation invocationWithMethodSignature:showHiddenFilesSignature];
+    [showHiddenFilesInvocation setSelector:showHiddenFilesSelector];
+    [showHiddenFilesInvocation setTarget:navView];
+    [showHiddenFilesInvocation setArgument:&show atIndex:2];
+    [showHiddenFilesInvocation invoke];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+nsFilePicker::nsFilePicker() : mSelectedTypeIndex(0) {}
+
+nsFilePicker::~nsFilePicker() {}
+
+void nsFilePicker::InitNative(nsIWidget* aParent, const nsAString& aTitle) {
+  mTitle = aTitle;
+}
+
+NSView* nsFilePicker::GetAccessoryView() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSView* accessoryView =
+      [[[NSView alloc] initWithFrame:NSMakeRect(0, 0, 0, 0)] autorelease];
+
+  // Set a label's default value.
+  NSString* label = @"Format:";
+
+  // Try to get the localized string.
+  nsCOMPtr<nsIStringBundleService> sbs =
+      do_GetService(NS_STRINGBUNDLE_CONTRACTID);
+  nsCOMPtr<nsIStringBundle> bundle;
+  nsresult rv = sbs->CreateBundle(
+      "chrome://global/locale/filepicker.properties", getter_AddRefs(bundle));
+  if (NS_SUCCEEDED(rv)) {
+    nsAutoString locaLabel;
+    rv = bundle->GetStringFromName("formatLabel", locaLabel);
+    if (NS_SUCCEEDED(rv)) {
+      label = [NSString
+          stringWithCharacters:reinterpret_cast<const unichar*>(locaLabel.get())
+                        length:locaLabel.Length()];
+    }
+  }
+
+  // set up label text field
+  NSTextField* textField = [[[NSTextField alloc] init] autorelease];
+  [textField setEditable:NO];
+  [textField setSelectable:NO];
+  [textField setDrawsBackground:NO];
+  [textField setBezeled:NO];
+  [textField setBordered:NO];
+  [textField setFont:[NSFont labelFontOfSize:13.0]];
+  [textField setStringValue:label];
+  [textField setTag:0];
+  [textField sizeToFit];
+
+  // set up popup button
+  NSPopUpButton* popupButton =
+      [[[NSPopUpButton alloc] initWithFrame:NSMakeRect(0, 0, 0, 0)
+                                  pullsDown:NO] autorelease];
+  uint32_t numMenuItems = mTitles.Length();
+  for (uint32_t i = 0; i < numMenuItems; i++) {
+    const nsString& currentTitle = mTitles[i];
+    NSString* titleString;
+    if (currentTitle.IsEmpty()) {
+      const nsString& currentFilter = mFilters[i];
+      titleString =
+          [[NSString alloc] initWithCharacters:reinterpret_cast<const unichar*>(
+                                                   currentFilter.get())
+                                        length:currentFilter.Length()];
+    } else {
+      titleString =
+          [[NSString alloc] initWithCharacters:reinterpret_cast<const unichar*>(
+                                                   currentTitle.get())
+                                        length:currentTitle.Length()];
+    }
+    [popupButton addItemWithTitle:titleString];
+    [titleString release];
+  }
+  if (mSelectedTypeIndex >= 0 && (uint32_t)mSelectedTypeIndex < numMenuItems)
+    [popupButton selectItemAtIndex:mSelectedTypeIndex];
+  [popupButton setTag:kSaveTypeControlTag];
+  [popupButton sizeToFit];  // we have to do sizeToFit to get the height
+                            // calculated for us
+  // This is just a default width that works well, doesn't truncate the vast
+  // majority of things that might end up in the menu.
+  [popupButton setFrameSize:NSMakeSize(180, [popupButton frame].size.height)];
+
+  // position everything based on control sizes with kAccessoryViewPadding pix
+  // padding on each side kAccessoryViewPadding pix horizontal padding between
+  // controls
+  float greatestHeight = [textField frame].size.height;
+  if ([popupButton frame].size.height > greatestHeight)
+    greatestHeight = [popupButton frame].size.height;
+  float totalViewHeight = greatestHeight + kAccessoryViewPadding * 2;
+  float totalViewWidth = [textField frame].size.width +
+                         [popupButton frame].size.width +
+                         kAccessoryViewPadding * 3;
+  [accessoryView setFrameSize:NSMakeSize(totalViewWidth, totalViewHeight)];
+
+  float textFieldOriginY =
+      ((greatestHeight - [textField frame].size.height) / 2 + 1) +
+      kAccessoryViewPadding;
+  [textField
+      setFrameOrigin:NSMakePoint(kAccessoryViewPadding, textFieldOriginY)];
+
+  float popupOriginX = [textField frame].size.width + kAccessoryViewPadding * 2;
+  float popupOriginY =
+      ((greatestHeight - [popupButton frame].size.height) / 2) +
+      kAccessoryViewPadding;
+  [popupButton setFrameOrigin:NSMakePoint(popupOriginX, popupOriginY)];
+
+  [accessoryView addSubview:textField];
+  [accessoryView addSubview:popupButton];
+  return accessoryView;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+// Display the file dialog
+nsresult nsFilePicker::Show(ResultCode* retval) {
+  NS_ENSURE_ARG_POINTER(retval);
+
+  *retval = returnCancel;
+
+  ResultCode userClicksOK = returnCancel;
+
+  mFiles.Clear();
+  nsCOMPtr<nsIFile> theFile;
+
+  // Note that GetLocalFolder shares a lot of code with GetLocalFiles.
+  // Could combine the functions and just pass the mode in.
+  switch (mMode) {
+    case modeOpen:
+      userClicksOK = GetLocalFiles(false, mFiles);
+      break;
+
+    case modeOpenMultiple:
+      userClicksOK = GetLocalFiles(true, mFiles);
+      break;
+
+    case modeSave:
+      userClicksOK = PutLocalFile(getter_AddRefs(theFile));
+      break;
+
+    case modeGetFolder:
+      userClicksOK = GetLocalFolder(getter_AddRefs(theFile));
+      break;
+
+    default:
+      NS_ERROR("Unknown file picker mode");
+      break;
+  }
+
+  if (theFile) mFiles.AppendObject(theFile);
+
+  *retval = userClicksOK;
+  return NS_OK;
+}
+
+static void UpdatePanelFileTypes(NSOpenPanel* aPanel, NSArray* aFilters) {
+  // If we show all file types, also "expose" bundles' contents.
+  [aPanel setTreatsFilePackagesAsDirectories:!aFilters];
+
+  [aPanel setAllowedFileTypes:aFilters];
+}
+
+@implementation NSPopUpButtonObserver
+- (void)setPopUpButton:(NSPopUpButton*)aPopUpButton {
+  mPopUpButton = aPopUpButton;
+}
+
+- (void)setOpenPanel:(NSOpenPanel*)aOpenPanel {
+  mOpenPanel = aOpenPanel;
+}
+
+- (void)setFilePicker:(nsFilePicker*)aFilePicker {
+  mFilePicker = aFilePicker;
+}
+
+- (void)menuChangedItem:(NSNotification*)aSender {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+  int32_t selectedItem = [mPopUpButton indexOfSelectedItem];
+  if (selectedItem < 0) {
+    return;
+  }
+
+  mFilePicker->SetFilterIndex(selectedItem);
+  UpdatePanelFileTypes(mOpenPanel, mFilePicker->GetFilterList());
+
+  NS_OBJC_END_TRY_BLOCK_RETURN();
+}
+@end
+
+// Use OpenPanel to do a GetFile. Returns |returnOK| if the user presses OK in
+// the dialog.
+nsIFilePicker::ResultCode nsFilePicker::GetLocalFiles(
+    bool inAllowMultiple, nsCOMArray<nsIFile>& outFiles) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  ResultCode retVal = nsIFilePicker::returnCancel;
+  NSOpenPanel* thePanel = [NSOpenPanel openPanel];
+
+  SetShowHiddenFileState(thePanel);
+
+  // Set the options for how the get file dialog will appear
+  SetDialogTitle(mTitle, thePanel);
+  [thePanel setAllowsMultipleSelection:inAllowMultiple];
+  [thePanel setCanSelectHiddenExtension:YES];
+  [thePanel setCanChooseDirectories:NO];
+  [thePanel setCanChooseFiles:YES];
+  [thePanel setResolvesAliases:YES];
+
+  // Get filters
+  // filters may be null, if we should allow all file types.
+  NSArray* filters = GetFilterList();
+
+  // set up default directory
+  NSString* theDir = PanelDefaultDirectory();
+
+  // if this is the "Choose application..." dialog, and no other start
+  // dir has been set, then use the Applications folder.
+  if (!theDir) {
+    if (filters && [filters count] == 1 &&
+        [(NSString*)[filters objectAtIndex:0] isEqualToString:@"app"])
+      theDir = @"/Applications/";
+    else
+      theDir = @"";
+  }
+
+  if (theDir) {
+    [thePanel setDirectoryURL:[NSURL fileURLWithPath:theDir isDirectory:YES]];
+  }
+
+  int result;
+  nsCocoaUtils::PrepareForNativeAppModalDialog();
+  if (mFilters.Length() > 1) {
+    // [NSURL initWithString:] (below) throws an exception if URLString is nil.
+
+    NSPopUpButtonObserver* observer = [[NSPopUpButtonObserver alloc] init];
+
+    NSView* accessoryView = GetAccessoryView();
+    [thePanel setAccessoryView:accessoryView];
+
+    [observer setPopUpButton:[accessoryView viewWithTag:kSaveTypeControlTag]];
+    [observer setOpenPanel:thePanel];
+    [observer setFilePicker:this];
+
+    [[NSNotificationCenter defaultCenter]
+        addObserver:observer
+           selector:@selector(menuChangedItem:)
+               name:NSMenuWillSendActionNotification
+             object:nil];
+
+    UpdatePanelFileTypes(thePanel, filters);
+    result = [thePanel runModal];
+
+    [[NSNotificationCenter defaultCenter] removeObserver:observer];
+    [observer release];
+  } else {
+    // If we show all file types, also "expose" bundles' contents.
+    if (!filters) {
+      [thePanel setTreatsFilePackagesAsDirectories:YES];
+    }
+    [thePanel setAllowedFileTypes:filters];
+    result = [thePanel runModal];
+  }
+  nsCocoaUtils::CleanUpAfterNativeAppModalDialog();
+
+  if (result == NSModalResponseCancel) return retVal;
+
+  // Converts data from a NSArray of NSURL to the returned format.
+  // We should be careful to not call [thePanel URLs] more than once given that
+  // it creates a new array each time.
+  // We are using Fast Enumeration, thus the NSURL array is created once then
+  // iterated.
+  for (NSURL* url in [thePanel URLs]) {
+    if (!url) {
+      continue;
+    }
+
+    nsCOMPtr<nsIFile> localFile;
+    NS_NewLocalFile(u""_ns, true, getter_AddRefs(localFile));
+    nsCOMPtr<nsILocalFileMac> macLocalFile = do_QueryInterface(localFile);
+    if (macLocalFile &&
+        NS_SUCCEEDED(macLocalFile->InitWithCFURL((CFURLRef)url))) {
+      outFiles.AppendObject(localFile);
+    }
+  }
+
+  if (outFiles.Count() > 0) retVal = returnOK;
+
+  return retVal;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nsIFilePicker::returnOK);
+}
+
+// Use OpenPanel to do a GetFolder. Returns |returnOK| if the user presses OK in
+// the dialog.
+nsIFilePicker::ResultCode nsFilePicker::GetLocalFolder(nsIFile** outFile) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+  NS_ASSERTION(
+      outFile,
+      "this protected member function expects a null initialized out pointer");
+
+  ResultCode retVal = nsIFilePicker::returnCancel;
+  NSOpenPanel* thePanel = [NSOpenPanel openPanel];
+
+  SetShowHiddenFileState(thePanel);
+
+  // Set the options for how the get file dialog will appear
+  SetDialogTitle(mTitle, thePanel);
+  [thePanel setAllowsMultipleSelection:NO];
+  [thePanel setCanSelectHiddenExtension:YES];
+  [thePanel setCanChooseDirectories:YES];
+  [thePanel setCanChooseFiles:NO];
+  [thePanel setResolvesAliases:YES];
+  [thePanel setCanCreateDirectories:YES];
+
+  // packages != folders
+  [thePanel setTreatsFilePackagesAsDirectories:NO];
+
+  // set up default directory
+  NSString* theDir = PanelDefaultDirectory();
+  if (theDir) {
+    [thePanel setDirectoryURL:[NSURL fileURLWithPath:theDir isDirectory:YES]];
+  }
+  nsCocoaUtils::PrepareForNativeAppModalDialog();
+  int result = [thePanel runModal];
+  nsCocoaUtils::CleanUpAfterNativeAppModalDialog();
+
+  if (result == NSModalResponseCancel) return retVal;
+
+  // get the path for the folder (we allow just 1, so that's all we get)
+  NSURL* theURL = [[thePanel URLs] objectAtIndex:0];
+  if (theURL) {
+    nsCOMPtr<nsIFile> localFile;
+    NS_NewLocalFile(u""_ns, true, getter_AddRefs(localFile));
+    nsCOMPtr<nsILocalFileMac> macLocalFile = do_QueryInterface(localFile);
+    if (macLocalFile &&
+        NS_SUCCEEDED(macLocalFile->InitWithCFURL((CFURLRef)theURL))) {
+      *outFile = localFile;
+      NS_ADDREF(*outFile);
+      retVal = returnOK;
+    }
+  }
+
+  return retVal;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nsIFilePicker::returnOK);
+}
+
+// Returns |returnOK| if the user presses OK in the dialog.
+nsIFilePicker::ResultCode nsFilePicker::PutLocalFile(nsIFile** outFile) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+  NS_ASSERTION(
+      outFile,
+      "this protected member function expects a null initialized out pointer");
+
+  ResultCode retVal = nsIFilePicker::returnCancel;
+  NSSavePanel* thePanel = [NSSavePanel savePanel];
+
+  SetShowHiddenFileState(thePanel);
+
+  SetDialogTitle(mTitle, thePanel);
+
+  // set up accessory view for file format options
+  NSView* accessoryView = GetAccessoryView();
+  [thePanel setAccessoryView:accessoryView];
+
+  // set up default file name
+  NSString* defaultFilename =
+      [NSString stringWithCharacters:(const unichar*)mDefaultFilename.get()
+                              length:mDefaultFilename.Length()];
+
+  // Set up the allowed type. This prevents the extension from being selected.
+  NSString* extension = defaultFilename.pathExtension;
+  if (extension.length != 0) {
+    thePanel.allowedFileTypes = @[ extension ];
+  }
+  // Allow users to change the extension.
+  thePanel.allowsOtherFileTypes = YES;
+
+  // If extensions are hidden and we’re saving a file with multiple extensions,
+  // only the last extension will be hidden in the panel (".tar.gz" will become
+  // ".tar"). If the remaining extension is known, the OS will think that we're
+  // trying to add a non-default extension. To avoid the confusion, we ensure
+  // that all extensions are shown in the panel if the remaining extension is
+  // known by the OS.
+  NSString* fileName =
+      [[defaultFilename lastPathComponent] stringByDeletingPathExtension];
+  NSString* otherExtension = fileName.pathExtension;
+  if (otherExtension.length != 0) {
+    // There's another extension here. Get the UTI.
+    CFStringRef type = UTTypeCreatePreferredIdentifierForTag(
+        kUTTagClassFilenameExtension, (CFStringRef)otherExtension, NULL);
+    if (type) {
+      if (!CFStringHasPrefix(type, CFSTR("dyn."))) {
+        // We have a UTI, otherwise the type would have a "dyn." prefix. Ensure
+        // extensions are shown in the panel.
+        [thePanel setExtensionHidden:NO];
+      }
+      CFRelease(type);
+    }
+  }
+
+  // set up default directory
+  NSString* theDir = PanelDefaultDirectory();
+  if (theDir) {
+    [thePanel setDirectoryURL:[NSURL fileURLWithPath:theDir isDirectory:YES]];
+  }
+
+  // load the panel
+  nsCocoaUtils::PrepareForNativeAppModalDialog();
+  [thePanel setNameFieldStringValue:defaultFilename];
+  int result = [thePanel runModal];
+  nsCocoaUtils::CleanUpAfterNativeAppModalDialog();
+  if (result == NSModalResponseCancel) return retVal;
+
+  // get the save type
+  NSPopUpButton* popupButton = [accessoryView viewWithTag:kSaveTypeControlTag];
+  if (popupButton) {
+    mSelectedTypeIndex = [popupButton indexOfSelectedItem];
+  }
+
+  NSURL* fileURL = [thePanel URL];
+  if (fileURL) {
+    nsCOMPtr<nsIFile> localFile;
+    NS_NewLocalFile(u""_ns, true, getter_AddRefs(localFile));
+    nsCOMPtr<nsILocalFileMac> macLocalFile = do_QueryInterface(localFile);
+    if (macLocalFile &&
+        NS_SUCCEEDED(macLocalFile->InitWithCFURL((CFURLRef)fileURL))) {
+      *outFile = localFile;
+      NS_ADDREF(*outFile);
+      // We tell if we are replacing or not by just looking to see if the file
+      // exists. The user could not have hit OK and not meant to replace the
+      // file.
+      if ([[NSFileManager defaultManager] fileExistsAtPath:[fileURL path]])
+        retVal = returnReplace;
+      else
+        retVal = returnOK;
+    }
+  }
+
+  return retVal;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nsIFilePicker::returnCancel);
+}
+
+NSArray* nsFilePicker::GetFilterList() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!mFilters.Length()) {
+    return nil;
+  }
+
+  if (mFilters.Length() <= (uint32_t)mSelectedTypeIndex) {
+    NS_WARNING("An out of range index has been selected. Using the first index "
+               "instead.");
+    mSelectedTypeIndex = 0;
+  }
+
+  const nsString& filterWide = mFilters[mSelectedTypeIndex];
+  if (!filterWide.Length()) {
+    return nil;
+  }
+
+  if (filterWide.Equals(u"*"_ns)) {
+    return nil;
+  }
+
+  // The extensions in filterWide are in the format "*.ext" but are expected
+  // in the format "ext" by NSOpenPanel. So we need to filter some characters.
+  NSMutableString* filterString = [[[NSMutableString alloc]
+      initWithString:[NSString
+                         stringWithCharacters:reinterpret_cast<const unichar*>(
+                                                  filterWide.get())
+                                       length:filterWide.Length()]]
+      autorelease];
+  NSCharacterSet* set =
+      [NSCharacterSet characterSetWithCharactersInString:@". *"];
+  NSRange range = [filterString rangeOfCharacterFromSet:set];
+  while (range.length) {
+    [filterString replaceCharactersInRange:range withString:@""];
+    range = [filterString rangeOfCharacterFromSet:set];
+  }
+
+  return [[[NSArray alloc]
+      initWithArray:[filterString componentsSeparatedByString:@";"]]
+      autorelease];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+// Sets the dialog title to whatever it should be.  If it fails, eh,
+// the OS will provide a sensible default.
+void nsFilePicker::SetDialogTitle(const nsString& inTitle, id aPanel) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [aPanel setTitle:[NSString stringWithCharacters:(const unichar*)inTitle.get()
+                                           length:inTitle.Length()]];
+
+  if (!mOkButtonLabel.IsEmpty()) {
+    [aPanel
+        setPrompt:[NSString
+                      stringWithCharacters:(const unichar*)mOkButtonLabel.get()
+                                    length:mOkButtonLabel.Length()]];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Converts path from an nsIFile into a NSString path
+// If it fails, returns an empty string.
+NSString* nsFilePicker::PanelDefaultDirectory() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSString* directory = nil;
+  if (mDisplayDirectory) {
+    nsAutoString pathStr;
+    mDisplayDirectory->GetPath(pathStr);
+    directory = [[[NSString alloc]
+        initWithCharacters:reinterpret_cast<const unichar*>(pathStr.get())
+                    length:pathStr.Length()] autorelease];
+  }
+  return directory;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+NS_IMETHODIMP nsFilePicker::GetFile(nsIFile** aFile) {
+  NS_ENSURE_ARG_POINTER(aFile);
+  *aFile = nullptr;
+
+  // just return the first file
+  if (mFiles.Count() > 0) {
+    *aFile = mFiles.ObjectAt(0);
+    NS_IF_ADDREF(*aFile);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsFilePicker::GetFileURL(nsIURI** aFileURL) {
+  NS_ENSURE_ARG_POINTER(aFileURL);
+  *aFileURL = nullptr;
+
+  if (mFiles.Count() == 0) return NS_OK;
+
+  return NS_NewFileURI(aFileURL, mFiles.ObjectAt(0));
+}
+
+NS_IMETHODIMP nsFilePicker::GetFiles(nsISimpleEnumerator** aFiles) {
+  return NS_NewArrayEnumerator(aFiles, mFiles, NS_GET_IID(nsIFile));
+}
+
+NS_IMETHODIMP nsFilePicker::SetDefaultString(const nsAString& aString) {
+  mDefaultFilename = aString;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsFilePicker::GetDefaultString(nsAString& aString) {
+  return NS_ERROR_FAILURE;
+}
+
+// The default extension to use for files
+NS_IMETHODIMP nsFilePicker::GetDefaultExtension(nsAString& aExtension) {
+  aExtension.Truncate();
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsFilePicker::SetDefaultExtension(const nsAString& aExtension) {
+  return NS_OK;
+}
+
+// Append an entry to the filters array
+NS_IMETHODIMP
+nsFilePicker::AppendFilter(const nsAString& aTitle, const nsAString& aFilter) {
+  // "..apps" has to be translated with native executable extensions.
+  if (aFilter.EqualsLiteral("..apps")) {
+    mFilters.AppendElement(u"*.app"_ns);
+  } else {
+    mFilters.AppendElement(aFilter);
+  }
+  mTitles.AppendElement(aTitle);
+
+  return NS_OK;
+}
+
+// Get the filter index - do we still need this?
+NS_IMETHODIMP nsFilePicker::GetFilterIndex(int32_t* aFilterIndex) {
+  *aFilterIndex = mSelectedTypeIndex;
+  return NS_OK;
+}
+
+// Set the filter index - do we still need this?
+NS_IMETHODIMP nsFilePicker::SetFilterIndex(int32_t aFilterIndex) {
+  mSelectedTypeIndex = aFilterIndex;
+  return NS_OK;
+}
diff --git a/widget/cocoa/nsLookAndFeel.h b/widget/cocoa/nsLookAndFeel.h
new file mode 100644
index 0000000000..adce685a4e
--- /dev/null
+++ b/widget/cocoa/nsLookAndFeel.h
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsLookAndFeel_h_
+#define nsLookAndFeel_h_
+#include "nsXPLookAndFeel.h"
+
+class nsLookAndFeel final : public nsXPLookAndFeel {
+ public:
+  nsLookAndFeel();
+  virtual ~nsLookAndFeel();
+
+  void NativeInit() final;
+  nsresult NativeGetColor(ColorID, ColorScheme, nscolor& aColor) override;
+  nsresult NativeGetInt(IntID, int32_t& aResult) override;
+  nsresult NativeGetFloat(FloatID, float& aResult) override;
+  bool NativeGetFont(FontID aID, nsString& aFontName,
+                     gfxFontStyle& aFontStyle) override;
+
+  virtual char16_t GetPasswordCharacterImpl() override {
+    // unicode value for the bullet character, used for password textfields.
+    return 0x2022;
+  }
+
+  void RecordLookAndFeelSpecificTelemetry() override {
+    RecordAccessibilityTelemetry();
+  }
+
+  // Having a separate, static method allows us to rely on the same
+  // chunk of telemetry logging code at initialization and when we
+  // recieve an event that changes the value of our telemetry probe.
+  static void RecordAccessibilityTelemetry();
+
+ protected:
+  static bool SystemWantsDarkTheme();
+  static bool IsSystemOrientationRTL();
+  static nscolor ProcessSelectionBackground(nscolor aColor,
+                                            ColorScheme aScheme);
+};
+
+#endif  // nsLookAndFeel_h_
diff --git a/widget/cocoa/nsLookAndFeel.mm b/widget/cocoa/nsLookAndFeel.mm
new file mode 100644
index 0000000000..73fd6b689c
--- /dev/null
+++ b/widget/cocoa/nsLookAndFeel.mm
@@ -0,0 +1,679 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AppearanceOverride.h"
+#include "mozilla/widget/ThemeChangeKind.h"
+#include "nsLookAndFeel.h"
+#include "nsCocoaFeatures.h"
+#include "nsNativeThemeColors.h"
+#include "nsStyleConsts.h"
+#include "nsIContent.h"
+#include "gfxFont.h"
+#include "gfxFontConstants.h"
+#include "gfxPlatformMac.h"
+#include "nsCSSColorUtils.h"
+#include "mozilla/FontPropertyTypes.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/widget/WidgetMessageUtils.h"
+
+#import <Cocoa/Cocoa.h>
+#import <AppKit/NSColor.h>
+
+// This must be included last:
+#include "nsObjCExceptions.h"
+
+using namespace mozilla;
+
+@interface MOZLookAndFeelDynamicChangeObserver : NSObject
++ (void)startObserving;
+@end
+
+nsLookAndFeel::nsLookAndFeel() = default;
+
+nsLookAndFeel::~nsLookAndFeel() = default;
+
+void nsLookAndFeel::NativeInit() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK
+
+  [MOZLookAndFeelDynamicChangeObserver startObserving];
+  RecordTelemetry();
+
+  NS_OBJC_END_TRY_ABORT_BLOCK
+}
+
+static nscolor GetColorFromNSColor(NSColor* aColor) {
+  NSColor* deviceColor =
+      [aColor colorUsingColorSpace:[NSColorSpace deviceRGBColorSpace]];
+  return NS_RGBA((unsigned int)(deviceColor.redComponent * 255.0),
+                 (unsigned int)(deviceColor.greenComponent * 255.0),
+                 (unsigned int)(deviceColor.blueComponent * 255.0),
+                 (unsigned int)(deviceColor.alphaComponent * 255.0));
+}
+
+static nscolor GetColorFromNSColorWithCustomAlpha(NSColor* aColor,
+                                                  float alpha) {
+  NSColor* deviceColor =
+      [aColor colorUsingColorSpace:[NSColorSpace deviceRGBColorSpace]];
+  return NS_RGBA((unsigned int)(deviceColor.redComponent * 255.0),
+                 (unsigned int)(deviceColor.greenComponent * 255.0),
+                 (unsigned int)(deviceColor.blueComponent * 255.0),
+                 (unsigned int)(alpha * 255.0));
+}
+
+// Turns an opaque selection color into a partially transparent selection color,
+// which usually leads to better contrast with the text color and which should
+// look more visually appealing in most contexts.
+// The idea is that the text and its regular, non-selected background are
+// usually chosen in such a way that they contrast well. Making the selection
+// color partially transparent causes the selection color to mix with the text's
+// regular background, so the end result will often have better contrast with
+// the text than an arbitrary opaque selection color.
+// The motivating example for this is the light selection color on dark web
+// pages: White text on a light blue selection color has very bad contrast,
+// whereas white text on dark blue (which what you get if you mix
+// partially-transparent light blue with the black textbox background) has much
+// better contrast.
+nscolor nsLookAndFeel::ProcessSelectionBackground(nscolor aColor,
+                                                  ColorScheme aScheme) {
+  if (aScheme == ColorScheme::Dark) {
+    // When we use a dark selection color, we do not change alpha because we do
+    // not use dark selection in content. The dark system color is appropriate
+    // for Firefox UI without needing to adjust its alpha.
+    return aColor;
+  }
+  uint16_t hue, sat, value;
+  uint8_t alpha;
+  nscolor resultColor = aColor;
+  NS_RGB2HSV(resultColor, hue, sat, value, alpha);
+  int factor = 2;
+  alpha = alpha / factor;
+  if (sat > 0) {
+    // The color is not a shade of grey, restore the saturation taken away by
+    // the transparency.
+    sat = mozilla::clamped(sat * factor, 0, 255);
+  } else {
+    // The color is a shade of grey, find the value that looks equivalent
+    // on a white background with the given opacity.
+    value = mozilla::clamped(255 - (255 - value) * factor, 0, 255);
+  }
+  NS_HSV2RGB(resultColor, hue, sat, value, alpha);
+  return resultColor;
+}
+
+nsresult nsLookAndFeel::NativeGetColor(ColorID aID, ColorScheme aScheme,
+                                       nscolor& aColor) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK
+
+  NSAppearance.currentAppearance = NSAppearanceForColorScheme(aScheme);
+
+  nscolor color = 0;
+  switch (aID) {
+    case ColorID::Infobackground:
+      color = aScheme == ColorScheme::Light
+                  ? NS_RGB(0xdd, 0xdd, 0xdd)
+                  : GetColorFromNSColor(NSColor.windowBackgroundColor);
+      break;
+    case ColorID::Highlight:
+      color = ProcessSelectionBackground(
+          GetColorFromNSColor(NSColor.selectedTextBackgroundColor), aScheme);
+      break;
+    // This is used to gray out the selection when it's not focused. Used with
+    // nsISelectionController::SELECTION_DISABLED.
+    case ColorID::TextSelectDisabledBackground:
+      color = ProcessSelectionBackground(
+          GetColorFromNSColor(NSColor.secondarySelectedControlColor), aScheme);
+      break;
+    case ColorID::MozMenuhoverdisabled:
+      aColor = NS_TRANSPARENT;
+      break;
+    case ColorID::Accentcolor:
+      color = GetColorFromNSColor(NSColor.controlAccentColor);
+      break;
+    case ColorID::MozMenuhover:
+    case ColorID::Selecteditem:
+      color = GetColorFromNSColor(NSColor.selectedContentBackgroundColor);
+      break;
+    case ColorID::Accentcolortext:
+    case ColorID::MozMenuhovertext:
+    case ColorID::Selecteditemtext:
+      color = GetColorFromNSColor(NSColor.selectedMenuItemTextColor);
+      break;
+    case ColorID::IMESelectedRawTextBackground:
+    case ColorID::IMESelectedConvertedTextBackground:
+    case ColorID::IMERawInputBackground:
+    case ColorID::IMEConvertedTextBackground:
+      color = NS_TRANSPARENT;
+      break;
+    case ColorID::IMESelectedRawTextForeground:
+    case ColorID::IMESelectedConvertedTextForeground:
+    case ColorID::IMERawInputForeground:
+    case ColorID::IMEConvertedTextForeground:
+    case ColorID::Highlighttext:
+      color = NS_SAME_AS_FOREGROUND_COLOR;
+      break;
+    case ColorID::IMERawInputUnderline:
+    case ColorID::IMEConvertedTextUnderline:
+      color = NS_40PERCENT_FOREGROUND_COLOR;
+      break;
+    case ColorID::IMESelectedRawTextUnderline:
+    case ColorID::IMESelectedConvertedTextUnderline:
+      color = NS_SAME_AS_FOREGROUND_COLOR;
+      break;
+
+      //
+      // css2 system colors http://www.w3.org/TR/REC-CSS2/ui.html#system-colors
+      //
+      // It's really hard to effectively map these to the Appearance Manager
+      // properly, since they are modeled word for word after the win32 system
+      // colors and don't have any real counterparts in the Mac world. I'm sure
+      // we'll be tweaking these for years to come.
+      //
+      // Thanks to mpt26@student.canterbury.ac.nz for the hardcoded values that
+      // form the defaults
+      //  if querying the Appearance Manager fails ;)
+      //
+    case ColorID::MozMacDefaultbuttontext:
+      color = NS_RGB(0xFF, 0xFF, 0xFF);
+      break;
+    case ColorID::MozSidebar:
+      color = aScheme == ColorScheme::Light ? NS_RGB(0xf6, 0xf6, 0xf6)
+                                            : NS_RGB(0x2d, 0x2d, 0x2d);
+      break;
+    case ColorID::MozSidebarborder:
+      // hsla(240, 5%, 5%, .1)
+      color = NS_RGBA(12, 12, 13, 26);
+      break;
+    case ColorID::MozButtonactivetext:
+      // Pre-macOS 12, pressed buttons were filled with the highlight color and
+      // the text was white. Starting with macOS 12, pressed (non-default)
+      // buttons are filled with medium gray and the text color is the same as
+      // in the non-pressed state.
+      color = nsCocoaFeatures::OnMontereyOrLater()
+                  ? GetColorFromNSColor(NSColor.controlTextColor)
+                  : NS_RGB(0xFF, 0xFF, 0xFF);
+      break;
+    case ColorID::Windowtext:
+      color = GetColorFromNSColor(NSColor.windowFrameTextColor);
+      break;
+    case ColorID::Appworkspace:
+      color = NS_RGB(0xFF, 0xFF, 0xFF);
+      break;
+    case ColorID::Background:
+      color = NS_RGB(0x63, 0x63, 0xCE);
+      break;
+    case ColorID::Buttonface:
+    case ColorID::MozButtonhoverface:
+    case ColorID::MozButtonactiveface:
+    case ColorID::MozButtondisabledface:
+    case ColorID::MozColheader:
+    case ColorID::MozColheaderhover:
+    case ColorID::MozColheaderactive:
+      color = GetColorFromNSColor(NSColor.controlColor);
+      if (!NS_GET_A(color)) {
+        color = GetColorFromNSColor(NSColor.controlBackgroundColor);
+      }
+      break;
+    case ColorID::Buttonhighlight:
+      color = GetColorFromNSColor(NSColor.selectedControlColor);
+      break;
+    case ColorID::Scrollbar:
+      color = GetColorFromNSColor(NSColor.scrollBarColor);
+      break;
+    case ColorID::Threedhighlight:
+      color = GetColorFromNSColor(NSColor.highlightColor);
+      break;
+    case ColorID::Buttonshadow:
+    case ColorID::Threeddarkshadow:
+      color = aScheme == ColorScheme::Dark ? *GenericDarkColor(aID)
+                                           : NS_RGB(0xDC, 0xDC, 0xDC);
+      break;
+    case ColorID::Threedshadow:
+      color = aScheme == ColorScheme::Dark ? *GenericDarkColor(aID)
+                                           : NS_RGB(0xE0, 0xE0, 0xE0);
+      break;
+    case ColorID::Threedface:
+      color = aScheme == ColorScheme::Dark ? *GenericDarkColor(aID)
+                                           : NS_RGB(0xF0, 0xF0, 0xF0);
+      break;
+    case ColorID::Threedlightshadow:
+    case ColorID::Buttonborder:
+    case ColorID::MozDisabledfield:
+      color = aScheme == ColorScheme::Dark ? *GenericDarkColor(aID)
+                                           : NS_RGB(0xDA, 0xDA, 0xDA);
+      break;
+    case ColorID::Menu:
+      // Hand-picked from Sonoma because there doesn't seem to be any
+      // appropriate menu system color.
+      color = aScheme == ColorScheme::Dark ? NS_RGB(0x36, 0x36, 0x39)
+                                           : NS_RGB(0xeb, 0xeb, 0xeb);
+      break;
+    case ColorID::Windowframe:
+      color = GetColorFromNSColor(NSColor.windowFrameColor);
+      break;
+    case ColorID::Window: {
+      color = GetColorFromNSColor(NSColor.windowBackgroundColor);
+      break;
+    }
+    case ColorID::Field:
+    case ColorID::MozCombobox:
+    case ColorID::MozDialog:
+      color = GetColorFromNSColor(NSColor.controlBackgroundColor);
+      break;
+    case ColorID::Fieldtext:
+    case ColorID::MozComboboxtext:
+    case ColorID::Buttontext:
+    case ColorID::MozButtonhovertext:
+    case ColorID::Menutext:
+    case ColorID::Infotext:
+    case ColorID::MozDialogtext:
+    case ColorID::MozCellhighlighttext:
+    case ColorID::MozColheadertext:
+    case ColorID::MozColheaderhovertext:
+    case ColorID::MozColheaderactivetext:
+    case ColorID::MozSidebartext:
+      color = GetColorFromNSColor(NSColor.controlTextColor);
+      break;
+    case ColorID::MozMacFocusring:
+      color = GetColorFromNSColorWithCustomAlpha(
+          NSColor.keyboardFocusIndicatorColor, 0.48);
+      break;
+    case ColorID::MozMacDisabledtoolbartext:
+    case ColorID::Graytext:
+      color = GetColorFromNSColor(NSColor.disabledControlTextColor);
+      break;
+    case ColorID::MozCellhighlight:
+      // For inactive list selection
+      color = GetColorFromNSColor(NSColor.secondarySelectedControlColor);
+      break;
+    case ColorID::MozEventreerow:
+      // Background color of even list rows.
+      color =
+          GetColorFromNSColor(NSColor.controlAlternatingRowBackgroundColors[0]);
+      break;
+    case ColorID::MozOddtreerow:
+      // Background color of odd list rows.
+      color =
+          GetColorFromNSColor(NSColor.controlAlternatingRowBackgroundColors[1]);
+      break;
+    case ColorID::MozNativehyperlinktext:
+      color = GetColorFromNSColor(NSColor.linkColor);
+      break;
+    case ColorID::MozNativevisitedhyperlinktext:
+      color = GetColorFromNSColor(NSColor.systemPurpleColor);
+      break;
+    case ColorID::MozHeaderbartext:
+    case ColorID::MozHeaderbarinactivetext:
+    case ColorID::Inactivecaptiontext:
+    case ColorID::Captiontext:
+      aColor = GetColorFromNSColor(NSColor.textColor);
+      return NS_OK;
+    case ColorID::MozHeaderbar:
+    case ColorID::MozHeaderbarinactive:
+    case ColorID::Inactivecaption:
+    case ColorID::Activecaption:
+      // This has better contrast than the stand-in colors.
+      aColor = GetColorFromNSColor(NSColor.windowBackgroundColor);
+      return NS_OK;
+    case ColorID::Marktext:
+    case ColorID::Mark:
+    case ColorID::SpellCheckerUnderline:
+    case ColorID::Activeborder:
+    case ColorID::Inactiveborder:
+      aColor = GetStandinForNativeColor(aID, aScheme);
+      return NS_OK;
+    default:
+      aColor = NS_RGB(0xff, 0xff, 0xff);
+      return NS_ERROR_FAILURE;
+  }
+
+  aColor = color;
+  return NS_OK;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK
+}
+
+nsresult nsLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  nsresult res = NS_OK;
+
+  switch (aID) {
+    case IntID::ScrollButtonLeftMouseButtonAction:
+      aResult = 0;
+      break;
+    case IntID::ScrollButtonMiddleMouseButtonAction:
+    case IntID::ScrollButtonRightMouseButtonAction:
+      aResult = 3;
+      break;
+    case IntID::CaretBlinkTime:
+      aResult = 567;
+      break;
+    case IntID::CaretWidth:
+      aResult = 1;
+      break;
+    case IntID::ShowCaretDuringSelection:
+      aResult = 0;
+      break;
+    case IntID::SelectTextfieldsOnKeyFocus:
+      // Select textfield content when focused by kbd
+      // used by EventStateManager::sTextfieldSelectModel
+      aResult = 1;
+      break;
+    case IntID::SubmenuDelay:
+      aResult = 200;
+      break;
+    case IntID::TooltipDelay:
+      aResult = 500;
+      break;
+    case IntID::MenusCanOverlapOSBar:
+      // xul popups are not allowed to overlap the menubar.
+      aResult = 0;
+      break;
+    case IntID::SkipNavigatingDisabledMenuItem:
+      aResult = 1;
+      break;
+    case IntID::DragThresholdX:
+    case IntID::DragThresholdY:
+      aResult = 4;
+      break;
+    case IntID::ScrollArrowStyle:
+      aResult = eScrollArrow_None;
+      break;
+    case IntID::UseOverlayScrollbars:
+    case IntID::AllowOverlayScrollbarsOverlap:
+      aResult = NSScroller.preferredScrollerStyle == NSScrollerStyleOverlay;
+      break;
+    case IntID::ScrollbarDisplayOnMouseMove:
+      aResult = 0;
+      break;
+    case IntID::ScrollbarFadeBeginDelay:
+      aResult = 450;
+      break;
+    case IntID::ScrollbarFadeDuration:
+      aResult = 200;
+      break;
+    case IntID::TreeOpenDelay:
+      aResult = 1000;
+      break;
+    case IntID::TreeCloseDelay:
+      aResult = 1000;
+      break;
+    case IntID::TreeLazyScrollDelay:
+      aResult = 150;
+      break;
+    case IntID::TreeScrollDelay:
+      aResult = 100;
+      break;
+    case IntID::TreeScrollLinesMax:
+      aResult = 3;
+      break;
+    case IntID::MacBigSurTheme:
+      aResult = nsCocoaFeatures::OnBigSurOrLater();
+      break;
+    case IntID::MacRTL:
+      aResult = IsSystemOrientationRTL();
+      break;
+    case IntID::AlertNotificationOrigin:
+      aResult = NS_ALERT_TOP;
+      break;
+    case IntID::TabFocusModel:
+      aResult = [NSApp isFullKeyboardAccessEnabled]
+                    ? nsIContent::eTabFocus_any
+                    : nsIContent::eTabFocus_textControlsMask;
+      break;
+    case IntID::ScrollToClick: {
+      aResult = [[NSUserDefaults standardUserDefaults]
+          boolForKey:@"AppleScrollerPagingBehavior"];
+    } break;
+    case IntID::ChosenMenuItemsShouldBlink:
+      aResult = 1;
+      break;
+    case IntID::IMERawInputUnderlineStyle:
+    case IntID::IMEConvertedTextUnderlineStyle:
+    case IntID::IMESelectedRawTextUnderlineStyle:
+    case IntID::IMESelectedConvertedTextUnderline:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Solid);
+      break;
+    case IntID::SpellCheckerUnderlineStyle:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Dotted);
+      break;
+    case IntID::ScrollbarButtonAutoRepeatBehavior:
+      aResult = 0;
+      break;
+    case IntID::SwipeAnimationEnabled:
+      aResult = NSEvent.isSwipeTrackingFromScrollEventsEnabled;
+      break;
+    case IntID::ContextMenuOffsetVertical:
+      aResult = -6;
+      break;
+    case IntID::ContextMenuOffsetHorizontal:
+      aResult = 1;
+      break;
+    case IntID::SystemUsesDarkTheme:
+      aResult = SystemWantsDarkTheme();
+      break;
+    case IntID::PrefersReducedMotion:
+      aResult =
+          NSWorkspace.sharedWorkspace.accessibilityDisplayShouldReduceMotion;
+      break;
+    case IntID::PrefersReducedTransparency:
+      aResult = NSWorkspace.sharedWorkspace
+                    .accessibilityDisplayShouldReduceTransparency;
+      break;
+    case IntID::InvertedColors:
+      aResult =
+          NSWorkspace.sharedWorkspace.accessibilityDisplayShouldInvertColors;
+      break;
+    case IntID::UseAccessibilityTheme:
+      aResult = NSWorkspace.sharedWorkspace
+                    .accessibilityDisplayShouldIncreaseContrast;
+      break;
+    case IntID::VideoDynamicRange: {
+      // If the platform says it supports HDR, then we claim to support
+      // video-dynamic-range.
+      gfxPlatform* platform = gfxPlatform::GetPlatform();
+      MOZ_ASSERT(platform);
+      aResult = platform->SupportsHDR();
+      break;
+    }
+    case IntID::PanelAnimations:
+      aResult = 1;
+      break;
+    default:
+      aResult = 0;
+      res = NS_ERROR_FAILURE;
+  }
+  return res;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+nsresult nsLookAndFeel::NativeGetFloat(FloatID aID, float& aResult) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  nsresult res = NS_OK;
+
+  switch (aID) {
+    case FloatID::IMEUnderlineRelativeSize:
+      aResult = 2.0f;
+      break;
+    case FloatID::SpellCheckerUnderlineRelativeSize:
+      aResult = 2.0f;
+      break;
+    case FloatID::CursorScale: {
+      id uaDefaults = [[NSUserDefaults alloc]
+          initWithSuiteName:@"com.apple.universalaccess"];
+      float f = [uaDefaults floatForKey:@"mouseDriverCursorSize"];
+      [uaDefaults release];
+      aResult = f > 0.0 ? f : 1.0;  // default to 1.0 if value not available
+      break;
+    }
+    default:
+      aResult = -1.0;
+      res = NS_ERROR_FAILURE;
+  }
+
+  return res;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+bool nsLookAndFeel::SystemWantsDarkTheme() {
+  // This returns true if the macOS system appearance is set to dark mode, false
+  // otherwise.
+  NSAppearanceName aquaOrDarkAqua =
+      [NSApp.effectiveAppearance bestMatchFromAppearancesWithNames:@[
+        NSAppearanceNameAqua, NSAppearanceNameDarkAqua
+      ]];
+  return [aquaOrDarkAqua isEqualToString:NSAppearanceNameDarkAqua];
+}
+
+/*static*/
+bool nsLookAndFeel::IsSystemOrientationRTL() {
+  NSWindow* window =
+      [[NSWindow alloc] initWithContentRect:NSZeroRect
+                                  styleMask:NSWindowStyleMaskBorderless
+                                    backing:NSBackingStoreBuffered
+                                      defer:NO];
+  auto direction = window.windowTitlebarLayoutDirection;
+  [window release];
+  return direction == NSUserInterfaceLayoutDirectionRightToLeft;
+}
+
+bool nsLookAndFeel::NativeGetFont(FontID aID, nsString& aFontName,
+                                  gfxFontStyle& aFontStyle) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  nsAutoCString name;
+  gfxPlatformMac::LookupSystemFont(aID, name, aFontStyle);
+  aFontName.Append(NS_ConvertUTF8toUTF16(name));
+
+  return true;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
+
+void nsLookAndFeel::RecordAccessibilityTelemetry() {
+  if ([[NSWorkspace sharedWorkspace]
+          respondsToSelector:@selector
+          (accessibilityDisplayShouldInvertColors)]) {
+    bool val =
+        [[NSWorkspace sharedWorkspace] accessibilityDisplayShouldInvertColors];
+    Telemetry::ScalarSet(Telemetry::ScalarID::A11Y_INVERT_COLORS, val);
+  }
+}
+
+@implementation MOZLookAndFeelDynamicChangeObserver
+
++ (void)startObserving {
+  static MOZLookAndFeelDynamicChangeObserver* gInstance = nil;
+  if (!gInstance) {
+    gInstance = [[MOZLookAndFeelDynamicChangeObserver alloc] init];  // leaked
+  }
+}
+
+- (instancetype)init {
+  self = [super init];
+
+  [NSNotificationCenter.defaultCenter
+      addObserver:self
+         selector:@selector(colorsChanged)
+             name:NSControlTintDidChangeNotification
+           object:nil];
+  [NSNotificationCenter.defaultCenter
+      addObserver:self
+         selector:@selector(colorsChanged)
+             name:NSSystemColorsDidChangeNotification
+           object:nil];
+
+  [NSWorkspace.sharedWorkspace.notificationCenter
+      addObserver:self
+         selector:@selector(mediaQueriesChanged)
+             name:NSWorkspaceAccessibilityDisplayOptionsDidChangeNotification
+           object:nil];
+
+  [NSNotificationCenter.defaultCenter
+      addObserver:self
+         selector:@selector(scrollbarsChanged)
+             name:NSPreferredScrollerStyleDidChangeNotification
+           object:nil];
+  [NSDistributedNotificationCenter.defaultCenter
+             addObserver:self
+                selector:@selector(scrollbarsChanged)
+                    name:@"AppleAquaScrollBarVariantChanged"
+                  object:nil
+      suspensionBehavior:NSNotificationSuspensionBehaviorDeliverImmediately];
+  [NSDistributedNotificationCenter.defaultCenter
+             addObserver:self
+                selector:@selector(cachedValuesChanged)
+                    name:@"AppleNoRedisplayAppearancePreferenceChanged"
+                  object:nil
+      suspensionBehavior:NSNotificationSuspensionBehaviorCoalesce];
+  [NSDistributedNotificationCenter.defaultCenter
+             addObserver:self
+                selector:@selector(cachedValuesChanged)
+                    name:@"com.apple.KeyboardUIModeDidChange"
+                  object:nil
+      suspensionBehavior:NSNotificationSuspensionBehaviorDeliverImmediately];
+
+  [MOZGlobalAppearance.sharedInstance addObserver:self
+                                       forKeyPath:@"effectiveAppearance"
+                                          options:0
+                                          context:nil];
+  [NSApp addObserver:self
+          forKeyPath:@"effectiveAppearance"
+             options:0
+             context:nil];
+
+  return self;
+}
+
+- (void)observeValueForKeyPath:(NSString*)keyPath
+                      ofObject:(id)object
+                        change:(NSDictionary<NSKeyValueChangeKey, id>*)change
+                       context:(void*)context {
+  if ([keyPath isEqualToString:@"effectiveAppearance"]) {
+    [self entireThemeChanged];
+  } else {
+    [super observeValueForKeyPath:keyPath
+                         ofObject:object
+                           change:change
+                          context:context];
+  }
+}
+
+- (void)entireThemeChanged {
+  LookAndFeel::NotifyChangedAllWindows(widget::ThemeChangeKind::StyleAndLayout);
+}
+
+- (void)scrollbarsChanged {
+  LookAndFeel::NotifyChangedAllWindows(widget::ThemeChangeKind::StyleAndLayout);
+}
+
+- (void)mediaQueriesChanged {
+  // Changing`Invert Colors` sends
+  // AccessibilityDisplayOptionsDidChangeNotifications. We monitor that setting
+  // via telemetry, so call into that recording method here.
+  nsLookAndFeel::RecordAccessibilityTelemetry();
+  LookAndFeel::NotifyChangedAllWindows(
+      widget::ThemeChangeKind::MediaQueriesOnly);
+}
+
+- (void)colorsChanged {
+  LookAndFeel::NotifyChangedAllWindows(widget::ThemeChangeKind::Style);
+}
+
+- (void)cachedValuesChanged {
+  // We only need to re-cache (and broadcast) updated LookAndFeel values, so
+  // that they're up-to-date the next time they're queried. No further change
+  // handling is needed.
+  // TODO: Add a change hint for this which avoids the unnecessary media query
+  // invalidation.
+  LookAndFeel::NotifyChangedAllWindows(
+      widget::ThemeChangeKind::MediaQueriesOnly);
+}
+@end
diff --git a/widget/cocoa/nsMacCursor.h b/widget/cocoa/nsMacCursor.h
new file mode 100644
index 0000000000..d68ebcf387
--- /dev/null
+++ b/widget/cocoa/nsMacCursor.h
@@ -0,0 +1,129 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsMacCursor_h_
+#define nsMacCursor_h_
+
+#import <Cocoa/Cocoa.h>
+#import "nsIWidget.h"
+
+/*! @class      nsMacCursor
+    @abstract   Represents a native Mac cursor.
+    @discussion <code>nsMacCursor</code> provides a simple API for creating and
+                working with native Macintosh cursors.  Cursors can be created
+                used without needing to be aware of the way different cursors
+                are implemented, in particular the details of managing an
+                animated cursor are hidden.
+*/
+@interface nsMacCursor : NSObject {
+ @private
+  NSTimer* mTimer;
+ @protected
+  nsCursor mType;
+  int mFrameCounter;
+}
+
+/*! @method     cursorWithCursor:
+    @abstract   Create a cursor by specifying a Cocoa <code>NSCursor</code>.
+    @discussion Creates a cursor representing the given Cocoa built-in cursor.
+    @param      aCursor the <code>NSCursor</code> to use
+    @param      aType the corresponding <code>nsCursor</code> constant
+    @result     an autoreleased instance of <code>nsMacCursor</code>
+                representing the given <code>NSCursor</code>
+ */
++ (nsMacCursor*)cursorWithCursor:(NSCursor*)aCursor type:(nsCursor)aType;
+
+/*! @method     cursorWithImageNamed:hotSpot:type:
+    @abstract   Create a cursor by specifying the name of an image resource to
+                use for the cursor and a hotspot.
+    @discussion Creates a cursor by loading the named image using the
+                <code>+[NSImage imageNamed:]</code> method.
+                <p>The image must be compatible with any restrictions laid down
+                by <code>NSCursor</code>. These vary by operating system
+                version.</p>
+                <p>The hotspot precisely determines the point where the user
+                clicks when using the cursor.</p>
+    @param      aCursor the name of the image to use for the cursor
+    @param      aPoint the point within the cursor to use as the hotspot
+    @param      aType the corresponding <code>nsCursor</code> constant
+    @result     an autoreleased instance of <code>nsMacCursor</code> that uses
+   the given image and hotspot
+ */
++ (nsMacCursor*)cursorWithImageNamed:(NSString*)aCursorImage
+                             hotSpot:(NSPoint)aPoint
+                                type:(nsCursor)aType;
+
+/*! @method     cursorWithFrames:type:
+    @abstract   Create an animated cursor by specifying the frames to use for
+                the animation.
+    @discussion Creates a cursor that will animate by cycling through the given
+                frames. Each element of the array must be an instance of
+                <code>NSCursor</code>
+    @param      aCursorFrames an array of <code>NSCursor</code>, representing
+                the frames of an animated cursor, in the order they should be
+                played.
+    @param      aType the corresponding <code>nsCursor</code> constant
+    @result     an autoreleased instance of <code>nsMacCursor</code> that will
+                animate the given cursor frames
+ */
++ (nsMacCursor*)cursorWithFrames:(NSArray*)aCursorFrames type:(nsCursor)aType;
+
+/*! @method     cocoaCursorWithImageNamed:hotSpot:
+    @abstract   Create a Cocoa NSCursor object with a Gecko image resource name
+                and a hotspot point.
+    @discussion Create a Cocoa NSCursor object with a Gecko image resource name
+                and a hotspot point.
+    @param      imageName the name of the gecko image resource, "tiff"
+                extension is assumed, do not append.
+    @param      aPoint the point within the cursor to use as the hotspot
+    @result     an autoreleased instance of <code>nsMacCursor</code> that will
+                animate the given cursor frames
+ */
++ (NSCursor*)cocoaCursorWithImageNamed:(NSString*)imageName
+                               hotSpot:(NSPoint)aPoint;
+
+/*! @method     isSet
+    @abstract   Determines whether this cursor is currently active.
+    @discussion This can be helpful when the Cocoa NSCursor state can be
+                influenced without going through nsCursorManager.
+    @result     whether the cursor is currently set
+ */
+- (BOOL)isSet;
+
+/*! @method     set
+    @abstract   Set the cursor.
+    @discussion Makes this cursor the current cursor. If the cursor is
+                animated, the animation is started.
+ */
+- (void)set;
+
+/*! @method     unset
+    @abstract   Unset the cursor. The cursor will return to the default
+                (usually the arrow cursor).
+    @discussion Unsets the cursor. If the cursor is animated, the animation is
+                stopped.
+ */
+- (void)unset;
+
+/*! @method     isAnimated
+    @abstract   Tests whether this cursor is animated.
+    @discussion Use this method to determine whether a cursor is animated
+    @result     YES if the cursor is animated (has more than one frame), NO if
+                it is a simple static cursor.
+ */
+- (BOOL)isAnimated;
+
+/** @method     cursorType
+    @abstract   Get the cursor type for this cursor
+    @discussion This method returns the <code>nsCursor</code> constant that
+                corresponds to this cursor, which is  equivalent to the CSS
+                name for the cursor.
+    @result     The nsCursor constant corresponding to this cursor, or
+                nsCursor's 'eCursorCount' if the cursor is a custom cursor
+                loaded from a URI
+ */
+- (nsCursor)type;
+@end
+
+#endif  // nsMacCursor_h_
diff --git a/widget/cocoa/nsMacCursor.mm b/widget/cocoa/nsMacCursor.mm
new file mode 100644
index 0000000000..c4dda5acab
--- /dev/null
+++ b/widget/cocoa/nsMacCursor.mm
@@ -0,0 +1,393 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsMacCursor.h"
+#include "nsObjCExceptions.h"
+#include "nsDebug.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsCOMPtr.h"
+#include "nsIFile.h"
+#include "nsString.h"
+
+/*! @category   nsMacCursor (PrivateMethods)
+    @abstract   Private methods internal to the nsMacCursor class.
+    @discussion <code>nsMacCursor</code> is effectively an abstract class. It
+   does not define complete behaviour in and of itself, the subclasses defined
+   in this file provide the useful implementations.
+*/
+@interface nsMacCursor (PrivateMethods)
+
+/*! @method     getNextCursorFrame
+    @abstract   get the index of the next cursor frame to display.
+    @discussion Increments and returns the frame counter of an animated cursor.
+    @result     The index of the next frame to display in the cursor animation
+*/
+- (int)getNextCursorFrame;
+
+/*! @method     numFrames
+    @abstract   Query the number of frames in this cursor's animation.
+    @discussion Returns the number of frames in this cursor's animation. Static
+   cursors return 1.
+*/
+- (int)numFrames;
+
+/*! @method     createTimer
+    @abstract   Create a Timer to use to animate the cursor.
+    @discussion Creates an instance of <code>NSTimer</code> which is used to
+   drive the cursor animation. This method should only be called for cursors
+   that are animated.
+*/
+- (void)createTimer;
+
+/*! @method     destroyTimer
+    @abstract   Destroy any timer instance associated with this cursor.
+    @discussion Invalidates and releases any <code>NSTimer</code> instance
+   associated with this cursor.
+ */
+- (void)destroyTimer;
+/*! @method     destroyTimer
+    @abstract   Destroy any timer instance associated with this cursor.
+    @discussion Invalidates and releases any <code>NSTimer</code> instance
+   associated with this cursor.
+*/
+
+/*! @method     advanceAnimatedCursor:
+    @abstract   Method called by animation timer to perform animation.
+    @discussion Called by an animated cursor's associated timer to advance the
+   animation to the next frame. Determines which frame should occur next and
+   sets the cursor to that frame.
+    @param      aTimer the timer causing the animation
+*/
+- (void)advanceAnimatedCursor:(NSTimer*)aTimer;
+
+/*! @method     setFrame:
+    @abstract   Sets the current cursor, using an index to determine which frame
+   in the animation to display.
+    @discussion Sets the current cursor. The frame index determines which frame
+   is shown if the cursor is animated. Frames and numbered from <code>0</code>
+   to <code>-[nsMacCursor numFrames] - 1</code>. A static cursor has a single
+   frame, numbered 0.
+    @param      aFrameIndex the index indicating which frame from the animation
+   to display
+*/
+- (void)setFrame:(int)aFrameIndex;
+
+@end
+
+/*! @class      nsCocoaCursor
+    @abstract   Implementation of <code>nsMacCursor</code> that uses Cocoa
+   <code>NSCursor</code> instances.
+    @discussion Displays a static or animated cursor, using Cocoa
+   <code>NSCursor</code> instances. These can be either built-in
+   <code>NSCursor</code> instances, or custom <code>NSCursor</code>s created
+   from images. When more than one <code>NSCursor</code> is provided, the cursor
+   will use these as animation frames.
+*/
+@interface nsCocoaCursor : nsMacCursor {
+ @private
+  NSArray* mFrames;
+  NSCursor* mLastSetCocoaCursor;
+}
+
+/*! @method     initWithFrames:
+    @abstract   Create an animated cursor by specifying the frames to use for
+   the animation.
+    @discussion Creates a cursor that will animate by cycling through the given
+   frames. Each element of the array must be an instance of
+   <code>NSCursor</code>
+    @param      aCursorFrames an array of <code>NSCursor</code>, representing
+   the frames of an animated cursor, in the order they should be played.
+    @param      aType the corresponding <code>nsCursor</code> constant
+    @result     an instance of <code>nsCocoaCursor</code> that will animate the
+   given cursor frames
+ */
+- (id)initWithFrames:(NSArray*)aCursorFrames type:(nsCursor)aType;
+
+/*! @method     initWithCursor:
+    @abstract   Create a cursor by specifying a Cocoa <code>NSCursor</code>.
+    @discussion Creates a cursor representing the given Cocoa built-in cursor.
+    @param      aCursor the <code>NSCursor</code> to use
+    @param      aType the corresponding <code>nsCursor</code> constant
+    @result     an instance of <code>nsCocoaCursor</code> representing the given
+   <code>NSCursor</code>
+*/
+- (id)initWithCursor:(NSCursor*)aCursor type:(nsCursor)aType;
+
+/*! @method     initWithImageNamed:hotSpot:
+    @abstract   Create a cursor by specifying the name of an image resource to
+   use for the cursor and a hotspot.
+    @discussion Creates a cursor by loading the named image using the
+   <code>+[NSImage imageNamed:]</code> method. <p>The image must be compatible
+   with any restrictions laid down by <code>NSCursor</code>. These vary by
+   operating system version.</p> <p>The hotspot precisely determines the point
+   where the user clicks when using the cursor.</p>
+    @param      aCursor the name of the image to use for the cursor
+    @param      aPoint the point within the cursor to use as the hotspot
+    @param      aType the corresponding <code>nsCursor</code> constant
+    @result     an instance of <code>nsCocoaCursor</code> that uses the given
+   image and hotspot
+*/
+- (id)initWithImageNamed:(NSString*)aCursorImage
+                 hotSpot:(NSPoint)aPoint
+                    type:(nsCursor)aType;
+
+@end
+
+@implementation nsMacCursor
+
++ (nsMacCursor*)cursorWithCursor:(NSCursor*)aCursor type:(nsCursor)aType {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return [[[nsCocoaCursor alloc] initWithCursor:aCursor
+                                           type:aType] autorelease];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
++ (nsMacCursor*)cursorWithImageNamed:(NSString*)aCursorImage
+                             hotSpot:(NSPoint)aPoint
+                                type:(nsCursor)aType {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return [[[nsCocoaCursor alloc] initWithImageNamed:aCursorImage
+                                            hotSpot:aPoint
+                                               type:aType] autorelease];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
++ (nsMacCursor*)cursorWithFrames:(NSArray*)aCursorFrames type:(nsCursor)aType {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return [[[nsCocoaCursor alloc] initWithFrames:aCursorFrames
+                                           type:aType] autorelease];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
++ (NSCursor*)cocoaCursorWithImageNamed:(NSString*)imageName
+                               hotSpot:(NSPoint)aPoint {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  nsCOMPtr<nsIFile> resDir;
+  nsAutoCString resPath;
+  NSString *pathToImage, *pathToHiDpiImage;
+  NSImage *cursorImage, *hiDpiCursorImage;
+
+  nsresult rv = NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(resDir));
+  if (NS_FAILED(rv)) goto INIT_FAILURE;
+  resDir->AppendNative("res"_ns);
+  resDir->AppendNative("cursors"_ns);
+
+  rv = resDir->GetNativePath(resPath);
+  if (NS_FAILED(rv)) goto INIT_FAILURE;
+
+  pathToImage = [NSString stringWithUTF8String:(const char*)resPath.get()];
+  if (!pathToImage) goto INIT_FAILURE;
+  pathToImage = [pathToImage stringByAppendingPathComponent:imageName];
+  pathToHiDpiImage = [pathToImage stringByAppendingString:@"@2x"];
+  // Add same extension to both image paths.
+  pathToImage = [pathToImage stringByAppendingPathExtension:@"png"];
+  pathToHiDpiImage = [pathToHiDpiImage stringByAppendingPathExtension:@"png"];
+
+  cursorImage =
+      [[[NSImage alloc] initWithContentsOfFile:pathToImage] autorelease];
+  if (!cursorImage) goto INIT_FAILURE;
+
+  // Note 1: There are a few different ways to get a hidpi image via
+  // initWithContentsOfFile. We let the OS handle this here: when the
+  // file basename ends in "@2x", it will be displayed at native resolution
+  // instead of being pixel-doubled. See bug 784909 comment 7 for alternates
+  // ways.
+  //
+  // Note 2: The OS is picky, and will ignore the hidpi representation
+  // unless it is exactly twice the size of the lowdpi image.
+  hiDpiCursorImage =
+      [[[NSImage alloc] initWithContentsOfFile:pathToHiDpiImage] autorelease];
+  if (hiDpiCursorImage) {
+    NSImageRep* imageRep = [[hiDpiCursorImage representations] objectAtIndex:0];
+    [cursorImage addRepresentation:imageRep];
+  }
+  return [[[NSCursor alloc] initWithImage:cursorImage
+                                  hotSpot:aPoint] autorelease];
+
+INIT_FAILURE:
+  NS_WARNING("Problem getting path to cursor image file!");
+  [self release];
+  return nil;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (BOOL)isSet {
+  // implemented by subclasses
+  return NO;
+}
+
+- (void)set {
+  if ([self isAnimated]) {
+    [self createTimer];
+  }
+  // if the cursor isn't animated or the timer creation fails for any reason...
+  if (!mTimer) {
+    [self setFrame:0];
+  }
+}
+
+- (void)unset {
+  [self destroyTimer];
+}
+
+- (BOOL)isAnimated {
+  return [self numFrames] > 1;
+}
+
+- (int)numFrames {
+  // subclasses need to override this to support animation
+  return 1;
+}
+
+- (int)getNextCursorFrame {
+  mFrameCounter = (mFrameCounter + 1) % [self numFrames];
+  return mFrameCounter;
+}
+
+- (void)createTimer {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!mTimer) {
+    mTimer = [[NSTimer
+        scheduledTimerWithTimeInterval:0.25
+                                target:self
+                              selector:@selector(advanceAnimatedCursor:)
+                              userInfo:nil
+                               repeats:YES] retain];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)destroyTimer {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mTimer) {
+    [mTimer invalidate];
+    [mTimer release];
+    mTimer = nil;
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)advanceAnimatedCursor:(NSTimer*)aTimer {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if ([aTimer isValid]) {
+    [self setFrame:[self getNextCursorFrame]];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)setFrame:(int)aFrameIndex {
+  // subclasses need to do something useful here
+}
+
+- (nsCursor)type {
+  return mType;
+}
+
+- (void)dealloc {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [self destroyTimer];
+  [super dealloc];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+@end
+
+@implementation nsCocoaCursor
+
+- (id)initWithFrames:(NSArray*)aCursorFrames type:(nsCursor)aType {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  self = [super init];
+  NSEnumerator* it = [aCursorFrames objectEnumerator];
+  NSObject* frame = nil;
+  while ((frame = [it nextObject])) {
+    NS_ASSERTION([frame isKindOfClass:[NSCursor class]],
+                 "Invalid argument: All frames must be of type NSCursor");
+  }
+  mFrames = [aCursorFrames retain];
+  mFrameCounter = 0;
+  mType = aType;
+  return self;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (id)initWithCursor:(NSCursor*)aCursor type:(nsCursor)aType {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSArray* frame = [NSArray arrayWithObjects:aCursor, nil];
+  return [self initWithFrames:frame type:aType];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (id)initWithImageNamed:(NSString*)aCursorImage
+                 hotSpot:(NSPoint)aPoint
+                    type:(nsCursor)aType {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return
+      [self initWithCursor:[nsMacCursor cocoaCursorWithImageNamed:aCursorImage
+                                                          hotSpot:aPoint]
+                      type:aType];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (BOOL)isSet {
+  return [NSCursor currentCursor] == mLastSetCocoaCursor;
+}
+
+- (void)setFrame:(int)aFrameIndex {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NSCursor* newCursor = [mFrames objectAtIndex:aFrameIndex];
+  [newCursor set];
+  mLastSetCocoaCursor = newCursor;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (int)numFrames {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return [mFrames count];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(0);
+}
+
+- (NSString*)description {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return [mFrames description];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (void)dealloc {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [mFrames release];
+  [super dealloc];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+@end
diff --git a/widget/cocoa/nsMacDockSupport.h b/widget/cocoa/nsMacDockSupport.h
new file mode 100644
index 0000000000..f3a12485b3
--- /dev/null
+++ b/widget/cocoa/nsMacDockSupport.h
@@ -0,0 +1,35 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIMacDockSupport.h"
+#include "nsIStandaloneNativeMenu.h"
+#include "nsITaskbarProgress.h"
+#include "nsCOMPtr.h"
+#include "nsString.h"
+
+@class MOZProgressDockOverlayView;
+
+class nsMacDockSupport : public nsIMacDockSupport, public nsITaskbarProgress {
+ public:
+  nsMacDockSupport();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMACDOCKSUPPORT
+  NS_DECL_NSITASKBARPROGRESS
+
+ protected:
+  virtual ~nsMacDockSupport();
+
+  nsCOMPtr<nsIStandaloneNativeMenu> mDockMenu;
+  nsString mBadgeText;
+
+  NSView* mDockTileWrapperView;
+  MOZProgressDockOverlayView* mProgressDockOverlayView;
+
+  nsTaskbarProgressState mProgressState;
+  double mProgressFraction;
+
+  nsresult UpdateDockTile();
+};
diff --git a/widget/cocoa/nsMacDockSupport.mm b/widget/cocoa/nsMacDockSupport.mm
new file mode 100644
index 0000000000..5e9da63e10
--- /dev/null
+++ b/widget/cocoa/nsMacDockSupport.mm
@@ -0,0 +1,436 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+#include <CoreFoundation/CoreFoundation.h>
+#include <signal.h>
+
+#include "nsCocoaUtils.h"
+#include "nsComponentManagerUtils.h"
+#include "nsMacDockSupport.h"
+#include "nsObjCExceptions.h"
+#include "nsNativeThemeColors.h"
+#include "nsString.h"
+
+NS_IMPL_ISUPPORTS(nsMacDockSupport, nsIMacDockSupport, nsITaskbarProgress)
+
+// This view is used in the dock tile when we're downloading a file.
+// It draws a progress bar that looks similar to the native progress bar on
+// 10.12. This style of progress bar is not animated, unlike the pre-10.10
+// progress bar look which had to redrawn multiple times per second.
+@interface MOZProgressDockOverlayView : NSView {
+  double mFractionValue;
+}
+@property double fractionValue;
+
+@end
+
+@implementation MOZProgressDockOverlayView
+
+@synthesize fractionValue = mFractionValue;
+
+- (void)drawRect:(NSRect)aRect {
+  // Erase the background behind this view, i.e. cut a rectangle hole in the
+  // icon.
+  [[NSColor clearColor] set];
+  NSRectFill(self.bounds);
+
+  // Split the height of this view into four quarters. The middle two quarters
+  // will be covered by the actual progress bar.
+  CGFloat radius = self.bounds.size.height / 4;
+  NSRect barBounds = NSInsetRect(self.bounds, 0, radius);
+
+  NSBezierPath* path = [NSBezierPath bezierPathWithRoundedRect:barBounds
+                                                       xRadius:radius
+                                                       yRadius:radius];
+
+  // Draw a grayish background first.
+  [[NSColor colorWithDeviceWhite:0 alpha:0.1] setFill];
+  [path fill];
+
+  // Draw a fill in the control accent color for the progress part.
+  NSRect progressFillRect = self.bounds;
+  progressFillRect.size.width *= mFractionValue;
+  [NSGraphicsContext saveGraphicsState];
+  [NSBezierPath clipRect:progressFillRect];
+  [[NSColor controlAccentColor] setFill];
+  [path fill];
+  [NSGraphicsContext restoreGraphicsState];
+
+  // Add a shadowy stroke on top.
+  [NSGraphicsContext saveGraphicsState];
+  [path addClip];
+  [[NSColor colorWithDeviceWhite:0 alpha:0.2] setStroke];
+  path.lineWidth = barBounds.size.height / 10;
+  [path stroke];
+  [NSGraphicsContext restoreGraphicsState];
+}
+
+@end
+
+nsMacDockSupport::nsMacDockSupport()
+    : mDockTileWrapperView(nil),
+      mProgressDockOverlayView(nil),
+      mProgressState(STATE_NO_PROGRESS),
+      mProgressFraction(0.0) {}
+
+nsMacDockSupport::~nsMacDockSupport() {
+  if (mDockTileWrapperView) {
+    [mDockTileWrapperView release];
+    mDockTileWrapperView = nil;
+  }
+  if (mProgressDockOverlayView) {
+    [mProgressDockOverlayView release];
+    mProgressDockOverlayView = nil;
+  }
+}
+
+NS_IMETHODIMP
+nsMacDockSupport::GetDockMenu(nsIStandaloneNativeMenu** aDockMenu) {
+  nsCOMPtr<nsIStandaloneNativeMenu> dockMenu(mDockMenu);
+  dockMenu.forget(aDockMenu);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMacDockSupport::SetDockMenu(nsIStandaloneNativeMenu* aDockMenu) {
+  mDockMenu = aDockMenu;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMacDockSupport::ActivateApplication(bool aIgnoreOtherApplications) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  [[NSApplication sharedApplication]
+      activateIgnoringOtherApps:aIgnoreOtherApplications];
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsMacDockSupport::SetBadgeText(const nsAString& aBadgeText) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSDockTile* tile = [[NSApplication sharedApplication] dockTile];
+  mBadgeText = aBadgeText;
+  if (aBadgeText.IsEmpty())
+    [tile setBadgeLabel:nil];
+  else
+    [tile
+        setBadgeLabel:[NSString
+                          stringWithCharacters:reinterpret_cast<const unichar*>(
+                                                   mBadgeText.get())
+                                        length:mBadgeText.Length()]];
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsMacDockSupport::GetBadgeText(nsAString& aBadgeText) {
+  aBadgeText = mBadgeText;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsMacDockSupport::SetProgressState(nsTaskbarProgressState aState,
+                                   uint64_t aCurrentValue, uint64_t aMaxValue) {
+  NS_ENSURE_ARG_RANGE(aState, 0, STATE_PAUSED);
+  if (aState == STATE_NO_PROGRESS || aState == STATE_INDETERMINATE) {
+    NS_ENSURE_TRUE(aCurrentValue == 0, NS_ERROR_INVALID_ARG);
+    NS_ENSURE_TRUE(aMaxValue == 0, NS_ERROR_INVALID_ARG);
+  }
+  if (aCurrentValue > aMaxValue) {
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+
+  mProgressState = aState;
+  if (aMaxValue == 0) {
+    mProgressFraction = 0;
+  } else {
+    mProgressFraction = (double)aCurrentValue / aMaxValue;
+  }
+
+  return UpdateDockTile();
+}
+
+nsresult nsMacDockSupport::UpdateDockTile() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (mProgressState == STATE_NORMAL || mProgressState == STATE_INDETERMINATE) {
+    if (!mDockTileWrapperView) {
+      // Create the following NSView hierarchy:
+      // * mDockTileWrapperView (NSView)
+      //    * imageView (NSImageView) <- has the application icon
+      //    * mProgressDockOverlayView (MOZProgressDockOverlayView) <- draws the
+      //    progress bar
+
+      mDockTileWrapperView =
+          [[NSView alloc] initWithFrame:NSMakeRect(0, 0, 32, 32)];
+      mDockTileWrapperView.autoresizingMask =
+          NSViewWidthSizable | NSViewHeightSizable;
+
+      NSImageView* imageView =
+          [[NSImageView alloc] initWithFrame:[mDockTileWrapperView bounds]];
+      imageView.image = [NSImage imageNamed:@"NSApplicationIcon"];
+      imageView.imageScaling = NSImageScaleAxesIndependently;
+      imageView.autoresizingMask = NSViewWidthSizable | NSViewHeightSizable;
+      [mDockTileWrapperView addSubview:imageView];
+
+      mProgressDockOverlayView = [[MOZProgressDockOverlayView alloc]
+          initWithFrame:NSMakeRect(1, 3, 30, 4)];
+      mProgressDockOverlayView.autoresizingMask =
+          NSViewMinXMargin | NSViewWidthSizable | NSViewMaxXMargin |
+          NSViewMinYMargin | NSViewHeightSizable | NSViewMaxYMargin;
+      [mDockTileWrapperView addSubview:mProgressDockOverlayView];
+    }
+    if (NSApp.dockTile.contentView != mDockTileWrapperView) {
+      NSApp.dockTile.contentView = mDockTileWrapperView;
+    }
+
+    if (mProgressState == STATE_NORMAL) {
+      mProgressDockOverlayView.fractionValue = mProgressFraction;
+    } else {
+      // Indeterminate states are rare. Just fill the entire progress bar in
+      // that case.
+      mProgressDockOverlayView.fractionValue = 1.0;
+    }
+    [NSApp.dockTile display];
+  } else if (NSApp.dockTile.contentView) {
+    NSApp.dockTile.contentView = nil;
+    [NSApp.dockTile display];
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+extern "C" {
+// Private CFURL API used by the Dock.
+CFPropertyListRef _CFURLCopyPropertyListRepresentation(CFURLRef url);
+CFURLRef _CFURLCreateFromPropertyListRepresentation(
+    CFAllocatorRef alloc, CFPropertyListRef pListRepresentation);
+}  // extern "C"
+
+namespace {
+
+const NSArray* const browserAppNames = [NSArray
+    arrayWithObjects:@"Firefox.app", @"Firefox Beta.app",
+                     @"Firefox Nightly.app", @"Safari.app", @"WebKit.app",
+                     @"Google Chrome.app", @"Google Chrome Canary.app",
+                     @"Chromium.app", @"Opera.app", nil];
+
+constexpr NSString* const kDockDomainName = @"com.apple.dock";
+// See https://developer.apple.com/documentation/devicemanagement/dock
+constexpr NSString* const kDockPersistentAppsKey = @"persistent-apps";
+// See
+// https://developer.apple.com/documentation/devicemanagement/dock/staticitem
+constexpr NSString* const kDockTileDataKey = @"tile-data";
+constexpr NSString* const kDockFileDataKey = @"file-data";
+
+NSArray* GetPersistentAppsFromDockPlist(NSDictionary* aDockPlist) {
+  if (!aDockPlist) {
+    return nil;
+  }
+  NSArray* persistentApps = [aDockPlist objectForKey:kDockPersistentAppsKey];
+  if (![persistentApps isKindOfClass:[NSArray class]]) {
+    return nil;
+  }
+  return persistentApps;
+}
+
+NSString* GetPathForApp(NSDictionary* aPersistantApp) {
+  if (![aPersistantApp isKindOfClass:[NSDictionary class]]) {
+    return nil;
+  }
+  NSDictionary* tileData = aPersistantApp[kDockTileDataKey];
+  if (![tileData isKindOfClass:[NSDictionary class]]) {
+    return nil;
+  }
+  NSDictionary* fileData = tileData[kDockFileDataKey];
+  if (![fileData isKindOfClass:[NSDictionary class]]) {
+    // Some special tiles may not have DockFileData but we can ignore those.
+    return nil;
+  }
+  NSURL* url = CFBridgingRelease(
+      _CFURLCreateFromPropertyListRepresentation(NULL, fileData));
+  if (!url) {
+    return nil;
+  }
+  return [url isFileURL] ? [url path] : nullptr;
+}
+
+// The only reliable way to get our changes to take effect seems to be to use
+// `kill`.
+void RefreshDock(NSDictionary* aDockPlist) {
+  [[NSUserDefaults standardUserDefaults] setPersistentDomain:aDockPlist
+                                                     forName:kDockDomainName];
+  NSRunningApplication* dockApp = [[NSRunningApplication
+      runningApplicationsWithBundleIdentifier:@"com.apple.dock"] firstObject];
+  if (!dockApp) {
+    return;
+  }
+  pid_t pid = [dockApp processIdentifier];
+  if (pid > 0) {
+    kill(pid, SIGTERM);
+  }
+}
+
+}  // namespace
+
+nsresult nsMacDockSupport::GetIsAppInDock(bool* aIsInDock) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  *aIsInDock = false;
+
+  NSDictionary* dockPlist = [[NSUserDefaults standardUserDefaults]
+      persistentDomainForName:kDockDomainName];
+  if (!dockPlist) {
+    return NS_ERROR_FAILURE;
+  }
+
+  NSArray* persistentApps = GetPersistentAppsFromDockPlist(dockPlist);
+  if (!persistentApps) {
+    return NS_ERROR_FAILURE;
+  }
+
+  NSString* appPath = [[NSBundle mainBundle] bundlePath];
+
+  for (id app in persistentApps) {
+    NSString* persistentAppPath = GetPathForApp(app);
+    if (persistentAppPath && [appPath isEqual:persistentAppPath]) {
+      *aIsInDock = true;
+      break;
+    }
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+nsresult nsMacDockSupport::EnsureAppIsPinnedToDock(
+    const nsAString& aAppPath, const nsAString& aAppToReplacePath,
+    bool* aIsInDock) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_ASSERT(aAppPath != aAppToReplacePath || !aAppPath.IsEmpty());
+
+  *aIsInDock = false;
+
+  NSString* appPath = !aAppPath.IsEmpty() ? nsCocoaUtils::ToNSString(aAppPath)
+                                          : [[NSBundle mainBundle] bundlePath];
+  NSString* appToReplacePath = nsCocoaUtils::ToNSString(aAppToReplacePath);
+
+  NSMutableDictionary* dockPlist = [NSMutableDictionary
+      dictionaryWithDictionary:[[NSUserDefaults standardUserDefaults]
+                                   persistentDomainForName:kDockDomainName]];
+  if (!dockPlist) {
+    return NS_ERROR_FAILURE;
+  }
+
+  NSMutableArray* persistentApps =
+      [NSMutableArray arrayWithArray:GetPersistentAppsFromDockPlist(dockPlist)];
+  if (!persistentApps) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // See the comment for this method in the .idl file for the strategy that we
+  // use here to determine where to pin the app.
+  NSUInteger preexistingAppIndex = NSNotFound;  // full path matches
+  NSUInteger sameNameAppIndex = NSNotFound;     // app name matches only
+  NSUInteger toReplaceAppIndex = NSNotFound;
+  NSUInteger lastBrowserAppIndex = NSNotFound;
+  for (NSUInteger index = 0; index < [persistentApps count]; ++index) {
+    NSString* persistentAppPath =
+        GetPathForApp([persistentApps objectAtIndex:index]);
+
+    if ([persistentAppPath isEqualToString:appPath]) {
+      preexistingAppIndex = index;
+    } else if (appToReplacePath &&
+               [persistentAppPath isEqualToString:appToReplacePath]) {
+      toReplaceAppIndex = index;
+    } else {
+      NSString* appName = [appPath lastPathComponent];
+      NSString* persistentAppName = [persistentAppPath lastPathComponent];
+
+      if ([persistentAppName isEqual:appName]) {
+        if ([appToReplacePath hasPrefix:@"/private/var/folders/"] &&
+            [appToReplacePath containsString:@"/AppTranslocation/"] &&
+            [persistentAppPath hasPrefix:@"/Volumes/"]) {
+          // This is a special case when an app with the same name was
+          // previously dragged and pinned from a quarantined DMG straight to
+          // the Dock and an attempt is now made to pin the same named app to
+          // the Dock. In this case we want to replace the currently pinned app
+          // icon.
+          toReplaceAppIndex = index;
+        } else {
+          sameNameAppIndex = index;
+        }
+      } else {
+        if ([browserAppNames containsObject:persistentAppName]) {
+          lastBrowserAppIndex = index;
+        }
+      }
+    }
+  }
+
+  // Special cases where we're not going to add a new Dock tile:
+  if (preexistingAppIndex != NSNotFound) {
+    if (toReplaceAppIndex != NSNotFound) {
+      [persistentApps removeObjectAtIndex:toReplaceAppIndex];
+      [dockPlist setObject:persistentApps forKey:kDockPersistentAppsKey];
+      RefreshDock(dockPlist);
+    }
+    *aIsInDock = true;
+    return NS_OK;
+  }
+
+  // Create new tile:
+  NSDictionary* newDockTile = nullptr;
+  {
+    NSURL* appUrl = [NSURL fileURLWithPath:appPath isDirectory:YES];
+    NSDictionary* dict = CFBridgingRelease(
+        _CFURLCopyPropertyListRepresentation((__bridge CFURLRef)appUrl));
+    if (!dict) {
+      return NS_ERROR_FAILURE;
+    }
+    NSDictionary* dockTileData =
+        [NSDictionary dictionaryWithObject:dict forKey:kDockFileDataKey];
+    if (dockTileData) {
+      newDockTile = [NSDictionary dictionaryWithObject:dockTileData
+                                                forKey:kDockTileDataKey];
+    }
+    if (!newDockTile) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  // Update the Dock:
+  if (toReplaceAppIndex != NSNotFound) {
+    [persistentApps replaceObjectAtIndex:toReplaceAppIndex
+                              withObject:newDockTile];
+  } else {
+    NSUInteger index;
+    if (sameNameAppIndex != NSNotFound) {
+      index = sameNameAppIndex + 1;
+    } else if (lastBrowserAppIndex != NSNotFound) {
+      index = lastBrowserAppIndex + 1;
+    } else {
+      index = [persistentApps count];
+    }
+    [persistentApps insertObject:newDockTile atIndex:index];
+  }
+  [dockPlist setObject:persistentApps forKey:kDockPersistentAppsKey];
+  RefreshDock(dockPlist);
+
+  *aIsInDock = true;
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
diff --git a/widget/cocoa/nsMacFinderProgress.h b/widget/cocoa/nsMacFinderProgress.h
new file mode 100644
index 0000000000..a0e48a0d59
--- /dev/null
+++ b/widget/cocoa/nsMacFinderProgress.h
@@ -0,0 +1,24 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef _MACFINDERPROGRESS_H_
+#define _MACFINDERPROGRESS_H_
+
+#include "nsIMacFinderProgress.h"
+#include "nsCOMPtr.h"
+
+class nsMacFinderProgress : public nsIMacFinderProgress {
+ public:
+  nsMacFinderProgress();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMACFINDERPROGRESS
+
+ protected:
+  virtual ~nsMacFinderProgress();
+
+  NSProgress* mProgress;
+};
+
+#endif
diff --git a/widget/cocoa/nsMacFinderProgress.mm b/widget/cocoa/nsMacFinderProgress.mm
new file mode 100644
index 0000000000..e2b0401313
--- /dev/null
+++ b/widget/cocoa/nsMacFinderProgress.mm
@@ -0,0 +1,93 @@
+/* -*- Mode: Objective-C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset:
+ * 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsMacFinderProgress.h"
+#include "nsProxyRelease.h"
+#include "nsThreadUtils.h"
+#include "nsString.h"
+#include "nsObjCExceptions.h"
+
+NS_IMPL_ISUPPORTS(nsMacFinderProgress, nsIMacFinderProgress)
+
+nsMacFinderProgress::nsMacFinderProgress() : mProgress(nil) {}
+
+nsMacFinderProgress::~nsMacFinderProgress() {
+  if (mProgress) {
+    [mProgress unpublish];
+    [mProgress release];
+  }
+}
+
+NS_IMETHODIMP
+nsMacFinderProgress::Init(
+    const nsAString& path,
+    nsIMacFinderProgressCanceledCallback* cancellationCallback) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSURL* pathUrl = [NSURL
+      fileURLWithPath:[NSString
+                          stringWithCharacters:reinterpret_cast<const unichar*>(
+                                                   path.BeginReading())
+                                        length:path.Length()]];
+  NSDictionary* userInfo = @{
+    @"NSProgressFileOperationKindKey" :
+        @"NSProgressFileOperationKindDownloading",
+    @"NSProgressFileURLKey" : pathUrl
+  };
+
+  mProgress = [[NSProgress alloc] initWithParent:nil userInfo:userInfo];
+  mProgress.kind = NSProgressKindFile;
+  mProgress.cancellable = YES;
+
+  nsMainThreadPtrHandle<nsIMacFinderProgressCanceledCallback>
+      cancellationCallbackHandle(
+          new nsMainThreadPtrHolder<nsIMacFinderProgressCanceledCallback>(
+              "MacFinderProgress::CancellationCallback", cancellationCallback));
+
+  mProgress.cancellationHandler = ^{
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "MacFinderProgress::Canceled", [cancellationCallbackHandle] {
+          MOZ_ASSERT(NS_IsMainThread());
+          cancellationCallbackHandle->Canceled();
+        }));
+  };
+
+  [mProgress publish];
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsMacFinderProgress::UpdateProgress(uint64_t currentProgress,
+                                    uint64_t totalProgress) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+  if (mProgress) {
+    mProgress.totalUnitCount = totalProgress;
+    mProgress.completedUnitCount = currentProgress;
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsMacFinderProgress::End() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (mProgress) {
+    [mProgress unpublish];
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
diff --git a/widget/cocoa/nsMacSharingService.h b/widget/cocoa/nsMacSharingService.h
new file mode 100644
index 0000000000..d97ce59380
--- /dev/null
+++ b/widget/cocoa/nsMacSharingService.h
@@ -0,0 +1,22 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsMacSharingService_h_
+#define nsMacSharingService_h_
+
+#include "nsIMacSharingService.h"
+
+class nsMacSharingService : public nsIMacSharingService {
+ public:
+  nsMacSharingService() {}
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMACSHARINGSERVICE
+
+ protected:
+  virtual ~nsMacSharingService() {}
+};
+
+#endif  // nsMacSharingService_h_
diff --git a/widget/cocoa/nsMacSharingService.mm b/widget/cocoa/nsMacSharingService.mm
new file mode 100644
index 0000000000..694617ba65
--- /dev/null
+++ b/widget/cocoa/nsMacSharingService.mm
@@ -0,0 +1,218 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsMacSharingService.h"
+
+#include "jsapi.h"
+#include "js/Array.h"               // JS::NewArrayObject
+#include "js/PropertyAndElement.h"  // JS_SetElement, JS_SetProperty
+#include "nsCocoaUtils.h"
+#include "mozilla/MacStringHelpers.h"
+
+NS_IMPL_ISUPPORTS(nsMacSharingService, nsIMacSharingService)
+
+NSString* const remindersServiceName =
+    @"com.apple.reminders.RemindersShareExtension";
+
+// These are some undocumented constants also used by Safari
+// to let us open the preferences window
+NSString* const extensionPrefPanePath =
+    @"/System/Library/PreferencePanes/Extensions.prefPane";
+const UInt32 openSharingSubpaneDescriptorType = 'ptru';
+NSString* const openSharingSubpaneActionKey = @"action";
+NSString* const openSharingSubpaneActionValue = @"revealExtensionPoint";
+NSString* const openSharingSubpaneProtocolKey = @"protocol";
+NSString* const openSharingSubpaneProtocolValue = @"com.apple.share-services";
+
+// Expose the id so we can pass reference through to JS and back
+@interface NSSharingService (ExposeName)
+- (id)name;
+@end
+
+// Filter providers that we do not want to expose to the user, because they are
+// duplicates or do not work correctly within the context
+static bool ShouldIgnoreProvider(NSString* aProviderName) {
+  return [aProviderName
+      isEqualToString:@"com.apple.share.System.add-to-safari-reading-list"];
+}
+
+// Clean up the activity once the share is complete
+@interface SharingServiceDelegate : NSObject <NSSharingServiceDelegate> {
+  NSUserActivity* mShareActivity;
+}
+
+- (void)cleanup;
+
+@end
+
+@implementation SharingServiceDelegate
+
+- (id)initWithActivity:(NSUserActivity*)activity {
+  self = [super init];
+  mShareActivity = [activity retain];
+  return self;
+}
+
+- (void)cleanup {
+  [mShareActivity resignCurrent];
+  [mShareActivity invalidate];
+  [mShareActivity release];
+  mShareActivity = nil;
+}
+
+- (void)sharingService:(NSSharingService*)sharingService
+         didShareItems:(NSArray*)items {
+  [self cleanup];
+}
+
+- (void)sharingService:(NSSharingService*)service
+    didFailToShareItems:(NSArray*)items
+                  error:(NSError*)error {
+  [self cleanup];
+}
+
+- (void)dealloc {
+  [mShareActivity release];
+  [super dealloc];
+}
+
+@end
+
+static NSString* NSImageToBase64(const NSImage* aImage) {
+  CGImageRef cgRef = [aImage CGImageForProposedRect:nil context:nil hints:nil];
+  NSBitmapImageRep* bitmapRep =
+      [[NSBitmapImageRep alloc] initWithCGImage:cgRef];
+  [bitmapRep setSize:[aImage size]];
+  NSData* imageData =
+      [bitmapRep representationUsingType:NSBitmapImageFileTypePNG
+                              properties:@{}];
+  NSString* base64Encoded = [imageData base64EncodedStringWithOptions:0];
+  [bitmapRep release];
+  return [NSString stringWithFormat:@"data:image/png;base64,%@", base64Encoded];
+}
+
+static void SetStrAttribute(JSContext* aCx, JS::Rooted<JSObject*>& aObj,
+                            const char* aKey, NSString* aVal) {
+  nsAutoString strVal;
+  mozilla::CopyCocoaStringToXPCOMString(aVal, strVal);
+  JS::Rooted<JSString*> title(aCx, JS_NewUCStringCopyZ(aCx, strVal.get()));
+  JS::Rooted<JS::Value> attVal(aCx, JS::StringValue(title));
+  JS_SetProperty(aCx, aObj, aKey, attVal);
+}
+
+nsresult nsMacSharingService::GetSharingProviders(
+    const nsAString& aPageUrl, JSContext* aCx,
+    JS::MutableHandle<JS::Value> aResult) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSURL* url = nsCocoaUtils::ToNSURL(aPageUrl);
+  if (!url) {
+    // aPageUrl is not a valid URL.
+    return NS_ERROR_FAILURE;
+  }
+
+  NSArray* sharingService = [NSSharingService sharingServicesForItems:@[ url ]];
+  int32_t serviceCount = 0;
+  JS::Rooted<JSObject*> array(aCx, JS::NewArrayObject(aCx, 0));
+
+  for (NSSharingService* currentService in sharingService) {
+    if (ShouldIgnoreProvider([currentService name])) {
+      continue;
+    }
+    JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+
+    SetStrAttribute(aCx, obj, "name", [currentService name]);
+    SetStrAttribute(aCx, obj, "menuItemTitle", currentService.menuItemTitle);
+    SetStrAttribute(aCx, obj, "image", NSImageToBase64(currentService.image));
+
+    JS::Rooted<JS::Value> element(aCx, JS::ObjectValue(*obj));
+    JS_SetElement(aCx, array, serviceCount++, element);
+  }
+
+  aResult.setObject(*array);
+
+  return NS_OK;
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsMacSharingService::OpenSharingPreferences() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSURL* prefPaneURL = [NSURL fileURLWithPath:extensionPrefPanePath
+                                  isDirectory:YES];
+  NSDictionary* args = @{
+    openSharingSubpaneActionKey : openSharingSubpaneActionValue,
+    openSharingSubpaneProtocolKey : openSharingSubpaneProtocolValue
+  };
+  NSData* data = [NSPropertyListSerialization
+      dataWithPropertyList:args
+                    format:NSPropertyListXMLFormat_v1_0
+                   options:0
+                     error:nil];
+  NSAppleEventDescriptor* descriptor = [[NSAppleEventDescriptor alloc]
+      initWithDescriptorType:openSharingSubpaneDescriptorType
+                        data:data];
+
+  [[NSWorkspace sharedWorkspace] openURLs:@[ prefPaneURL ]
+                  withAppBundleIdentifier:nil
+                                  options:NSWorkspaceLaunchAsync
+           additionalEventParamDescriptor:descriptor
+                        launchIdentifiers:NULL];
+
+  [descriptor release];
+
+  return NS_OK;
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsMacSharingService::ShareUrl(const nsAString& aServiceName,
+                              const nsAString& aPageUrl,
+                              const nsAString& aPageTitle) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSString* serviceName = nsCocoaUtils::ToNSString(aServiceName);
+  NSURL* pageUrl = nsCocoaUtils::ToNSURL(aPageUrl);
+  NSString* pageTitle = nsCocoaUtils::ToNSString(aPageTitle);
+  NSSharingService* service =
+      [NSSharingService sharingServiceNamed:serviceName];
+
+  // Reminders fetch its data from an activity, not the share data
+  if ([[service name] isEqual:remindersServiceName]) {
+    NSUserActivity* shareActivity = [[NSUserActivity alloc]
+        initWithActivityType:NSUserActivityTypeBrowsingWeb];
+
+    if ([pageUrl.scheme hasPrefix:@"http"]) {
+      [shareActivity setWebpageURL:pageUrl];
+    }
+    [shareActivity setEligibleForHandoff:NO];
+    [shareActivity setTitle:pageTitle];
+    [shareActivity becomeCurrent];
+
+    // Pass ownership of shareActivity to shareDelegate, which will release the
+    // activity once sharing has completed.
+    SharingServiceDelegate* shareDelegate =
+        [[SharingServiceDelegate alloc] initWithActivity:shareActivity];
+    [shareActivity release];
+
+    [service setDelegate:shareDelegate];
+    [shareDelegate release];
+  }
+
+  // Twitter likes the the title as an additional share item
+  NSArray* toShare = [[service name] isEqual:NSSharingServiceNamePostOnTwitter]
+                         ? @[ pageUrl, pageTitle ]
+                         : @[ pageUrl ];
+
+  [service setSubject:pageTitle];
+  [service performWithItems:toShare];
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
diff --git a/widget/cocoa/nsMacUserActivityUpdater.h b/widget/cocoa/nsMacUserActivityUpdater.h
new file mode 100644
index 0000000000..6870a66343
--- /dev/null
+++ b/widget/cocoa/nsMacUserActivityUpdater.h
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsMacUserActivityUpdater_h_
+#define nsMacUserActivityUpdater_h_
+
+#include "nsIMacUserActivityUpdater.h"
+#include "nsCocoaWindow.h"
+
+class nsMacUserActivityUpdater : public nsIMacUserActivityUpdater {
+ public:
+  nsMacUserActivityUpdater() {}
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMACUSERACTIVITYUPDATER
+
+ protected:
+  virtual ~nsMacUserActivityUpdater() {}
+  BaseWindow* GetCocoaWindow(nsIBaseWindow* aWindow);
+};
+
+#endif  // nsMacUserActivityUpdater_h_
diff --git a/widget/cocoa/nsMacUserActivityUpdater.mm b/widget/cocoa/nsMacUserActivityUpdater.mm
new file mode 100644
index 0000000000..9fedb618a4
--- /dev/null
+++ b/widget/cocoa/nsMacUserActivityUpdater.mm
@@ -0,0 +1,65 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsMacUserActivityUpdater.h"
+
+#include "nsCocoaUtils.h"
+#include "nsIBaseWindow.h"
+#include "gfxPlatform.h"
+
+NS_IMPL_ISUPPORTS(nsMacUserActivityUpdater, nsIMacUserActivityUpdater)
+
+NS_IMETHODIMP
+nsMacUserActivityUpdater::UpdateLocation(const nsAString& aPageUrl,
+                                         const nsAString& aPageTitle,
+                                         nsIBaseWindow* aWindow) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+  if (gfxPlatform::IsHeadless()) {
+    // In headless mode, Handoff will fail since there is no Cocoa window.
+    return NS_OK;
+  }
+
+  BaseWindow* cocoaWin = nsMacUserActivityUpdater::GetCocoaWindow(aWindow);
+  if (!cocoaWin) {
+    return NS_ERROR_FAILURE;
+  }
+
+  NSURL* pageUrl = nsCocoaUtils::ToNSURL(aPageUrl);
+  if (!pageUrl || (![pageUrl.scheme isEqualToString:@"https"] &&
+                   ![pageUrl.scheme isEqualToString:@"http"])) {
+    [cocoaWin.userActivity invalidate];
+    return NS_OK;
+  }
+
+  NSString* pageTitle = nsCocoaUtils::ToNSString(aPageTitle);
+  if (!pageTitle) {
+    pageTitle = pageUrl.absoluteString;
+  }
+
+  NSUserActivity* userActivity = [[NSUserActivity alloc]
+      initWithActivityType:NSUserActivityTypeBrowsingWeb];
+  userActivity.webpageURL = pageUrl;
+  userActivity.title = pageTitle;
+  cocoaWin.userActivity = userActivity;
+  [userActivity release];
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+BaseWindow* nsMacUserActivityUpdater::GetCocoaWindow(nsIBaseWindow* aWindow) {
+  nsCOMPtr<nsIWidget> widget = nullptr;
+  aWindow->GetMainWidget(getter_AddRefs(widget));
+  if (!widget) {
+    return nil;
+  }
+  BaseWindow* cocoaWin = (BaseWindow*)widget->GetNativeData(NS_NATIVE_WINDOW);
+  if (!cocoaWin) {
+    return nil;
+  }
+  return cocoaWin;
+}
diff --git a/widget/cocoa/nsMacWebAppUtils.h b/widget/cocoa/nsMacWebAppUtils.h
new file mode 100644
index 0000000000..1e79ca92d5
--- /dev/null
+++ b/widget/cocoa/nsMacWebAppUtils.h
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef _MAC_WEB_APP_UTILS_H_
+#define _MAC_WEB_APP_UTILS_H_
+
+#include "nsIMacWebAppUtils.h"
+
+#define NS_MACWEBAPPUTILS_CONTRACTID "@mozilla.org/widget/mac-web-app-utils;1"
+
+class nsMacWebAppUtils : public nsIMacWebAppUtils {
+ public:
+  nsMacWebAppUtils() {}
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIMACWEBAPPUTILS
+
+ protected:
+  virtual ~nsMacWebAppUtils() {}
+};
+
+#endif  //_MAC_WEB_APP_UTILS_H_
diff --git a/widget/cocoa/nsMacWebAppUtils.mm b/widget/cocoa/nsMacWebAppUtils.mm
new file mode 100644
index 0000000000..e1a06f873d
--- /dev/null
+++ b/widget/cocoa/nsMacWebAppUtils.mm
@@ -0,0 +1,98 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsMacWebAppUtils.h"
+#include "nsCOMPtr.h"
+#include "nsCocoaUtils.h"
+#include "nsString.h"
+
+// This must be included last:
+#include "nsObjCExceptions.h"
+
+// Find the path to the app with the given bundleIdentifier, if any.
+// Note that the OS will return the path to the newest binary, if there is more
+// than one. The determination of 'newest' is complex and beyond the scope of
+// this comment.
+
+NS_IMPL_ISUPPORTS(nsMacWebAppUtils, nsIMacWebAppUtils)
+
+NS_IMETHODIMP nsMacWebAppUtils::PathForAppWithIdentifier(
+    const nsAString& bundleIdentifier, nsAString& outPath) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  outPath.Truncate();
+
+  nsAutoreleasePool localPool;
+
+  // note that the result of this expression might be nil, meaning no matching
+  // app was found.
+  NSString* temp = [[NSWorkspace sharedWorkspace]
+      absolutePathForAppBundleWithIdentifier:
+          [NSString
+              stringWithCharacters:reinterpret_cast<const unichar*>(
+                                       ((nsString)bundleIdentifier).get())
+                            length:((nsString)bundleIdentifier).Length()]];
+
+  if (temp) {
+    // Copy out the resultant absolute path into outPath if non-nil.
+    nsCocoaUtils::GetStringForNSString(temp, outPath);
+  }
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP nsMacWebAppUtils::LaunchAppWithIdentifier(
+    const nsAString& bundleIdentifier) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  nsAutoreleasePool localPool;
+
+  // Note this might return false, meaning the app wasnt launched for some
+  // reason.
+  BOOL success = [[NSWorkspace sharedWorkspace]
+       launchAppWithBundleIdentifier:
+           [NSString
+               stringWithCharacters:reinterpret_cast<const unichar*>(
+                                        ((nsString)bundleIdentifier).get())
+                             length:((nsString)bundleIdentifier).Length()]
+                             options:(NSWorkspaceLaunchOptions)0
+      additionalEventParamDescriptor:nil
+                    launchIdentifier:NULL];
+
+  return success ? NS_OK : NS_ERROR_FAILURE;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP nsMacWebAppUtils::TrashApp(const nsAString& path,
+                                         nsITrashAppCallback* aCallback) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (NS_WARN_IF(!aCallback)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsCOMPtr<nsITrashAppCallback> callback = aCallback;
+
+  NSString* tempString =
+      [NSString stringWithCharacters:reinterpret_cast<const unichar*>(
+                                         ((nsString)path).get())
+                              length:path.Length()];
+
+  [[NSWorkspace sharedWorkspace]
+            recycleURLs:[NSArray
+                            arrayWithObject:[NSURL fileURLWithPath:tempString]]
+      completionHandler:^(NSDictionary* newURLs, NSError* error) {
+        nsresult rv = (error == nil) ? NS_OK : NS_ERROR_FAILURE;
+        callback->TrashAppFinished(rv);
+      }];
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
diff --git a/widget/cocoa/nsMenuBarX.h b/widget/cocoa/nsMenuBarX.h
new file mode 100644
index 0000000000..bcf124a7ac
--- /dev/null
+++ b/widget/cocoa/nsMenuBarX.h
@@ -0,0 +1,161 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsMenuBarX_h_
+#define nsMenuBarX_h_
+
+#import <Cocoa/Cocoa.h>
+
+#include "mozilla/UniquePtr.h"
+#include "mozilla/WeakPtr.h"
+
+#include "nsISupports.h"
+#include "nsMenuParentX.h"
+#include "nsChangeObserver.h"
+#include "nsTArray.h"
+#include "nsString.h"
+
+class nsMenuBarX;
+class nsMenuGroupOwnerX;
+class nsMenuX;
+class nsIWidget;
+class nsIContent;
+
+namespace mozilla {
+namespace dom {
+class Document;
+class Element;
+}  // namespace dom
+}  // namespace mozilla
+
+// ApplicationMenuDelegate is used to receive Cocoa notifications.
+@interface ApplicationMenuDelegate : NSObject <NSMenuDelegate> {
+  nsMenuBarX* mApplicationMenu;  // weak ref
+}
+- (id)initWithApplicationMenu:(nsMenuBarX*)aApplicationMenu;
+@end
+
+// Objective-C class used to allow us to intervene with keyboard event handling.
+// We allow mouse actions to work normally.
+@interface GeckoNSMenu : NSMenu {
+}
+- (BOOL)performSuperKeyEquivalent:(NSEvent*)aEvent;
+@end
+
+// Objective-C class used as action target for menu items
+@interface NativeMenuItemTarget : NSObject {
+}
+- (IBAction)menuItemHit:(id)aSender;
+@end
+
+// Objective-C class used for menu items on the Services menu to allow Gecko
+// to override their standard behavior in order to stop key equivalents from
+// firing in certain instances.
+@interface GeckoServicesNSMenuItem : NSMenuItem {
+}
+- (id)target;
+- (SEL)action;
+- (void)_doNothing:(id)aSender;
+@end
+
+// Objective-C class used as the Services menu so that Gecko can override the
+// standard behavior of the Services menu in order to stop key equivalents
+// from firing in certain instances.
+@interface GeckoServicesNSMenu : NSMenu {
+}
+- (void)addItem:(NSMenuItem*)aNewItem;
+- (NSMenuItem*)addItemWithTitle:(NSString*)aString
+                         action:(SEL)aSelector
+                  keyEquivalent:(NSString*)aKeyEquiv;
+- (void)insertItem:(NSMenuItem*)aNewItem atIndex:(NSInteger)aIndex;
+- (NSMenuItem*)insertItemWithTitle:(NSString*)aString
+                            action:(SEL)aSelector
+                     keyEquivalent:(NSString*)aKeyEquiv
+                           atIndex:(NSInteger)aIndex;
+- (void)_overrideClassOfMenuItem:(NSMenuItem*)aMenuItem;
+@end
+
+// Once instantiated, this object lives until its DOM node or its parent window
+// is destroyed. Do not hold references to this, they can become invalid any
+// time the DOM node can be destroyed.
+class nsMenuBarX : public nsMenuParentX,
+                   public nsChangeObserver,
+                   public mozilla::SupportsWeakPtr {
+ public:
+  explicit nsMenuBarX(mozilla::dom::Element* aElement);
+
+  NS_INLINE_DECL_REFCOUNTING(nsMenuBarX)
+
+  static NativeMenuItemTarget* sNativeEventTarget;
+  static nsMenuBarX* sLastGeckoMenuBarPainted;
+
+  // The following content nodes have been removed from the menu system.
+  // We save them here for use in command handling.
+  RefPtr<nsIContent> mAboutItemContent;
+  RefPtr<nsIContent> mPrefItemContent;
+  RefPtr<nsIContent> mAccountItemContent;
+  RefPtr<nsIContent> mQuitItemContent;
+
+  // nsChangeObserver
+  NS_DECL_CHANGEOBSERVER
+
+  // nsMenuParentX
+  nsMenuBarX* AsMenuBar() override { return this; }
+
+  // nsMenuBarX
+  uint32_t GetMenuCount();
+  bool MenuContainsAppMenu();
+  nsMenuX* GetMenuAt(uint32_t aIndex);
+  nsMenuX* GetXULHelpMenu();
+  void SetSystemHelpMenu();
+  nsresult Paint();
+  void ForceUpdateNativeMenuAt(const nsAString& aIndexString);
+  void ForceNativeMenuReload();  // used for testing
+  static void ResetNativeApplicationMenu();
+  void SetNeedsRebuild();
+  void ApplicationMenuOpened();
+  bool PerformKeyEquivalent(NSEvent* aEvent);
+  GeckoNSMenu* NativeNSMenu() { return mNativeMenu; }
+
+  // nsMenuParentX
+  void MenuChildChangedVisibility(const MenuChild& aChild,
+                                  bool aIsVisible) override;
+
+ protected:
+  virtual ~nsMenuBarX();
+
+  void ConstructNativeMenus();
+  void ConstructFallbackNativeMenus();
+  void InsertMenuAtIndex(RefPtr<nsMenuX>&& aMenu, uint32_t aIndex);
+  void RemoveMenuAtIndex(uint32_t aIndex);
+  RefPtr<mozilla::dom::Element> HideItem(mozilla::dom::Document* aDocument,
+                                         const nsAString& aID);
+  void AquifyMenuBar();
+  NSMenuItem* CreateNativeAppMenuItem(nsMenuX* aMenu, const nsAString& aNodeID,
+                                      SEL aAction, int aTag,
+                                      NativeMenuItemTarget* aTarget);
+  void CreateApplicationMenu(nsMenuX* aMenu);
+
+  // Calculates the index at which aChild's NSMenuItem should be inserted into
+  // our NSMenu. The order of NSMenuItems in the NSMenu is the same as the order
+  // of nsMenuX objects in mMenuArray; there are two differences:
+  //  - mMenuArray contains both visible and invisible menus, and the NSMenu
+  //  only contains visible
+  //    menus.
+  //  - Our NSMenu may also contain an item for the app menu, whereas mMenuArray
+  //  never does.
+  // So the insertion index is equal to the number of visible previous siblings
+  // of aChild in mMenuArray, plus one if the app menu is present.
+  NSInteger CalculateNativeInsertionPoint(nsMenuX* aChild);
+
+  RefPtr<nsIContent> mContent;
+  RefPtr<nsMenuGroupOwnerX> mMenuGroupOwner;
+  nsTArray<RefPtr<nsMenuX>> mMenuArray;
+  GeckoNSMenu* mNativeMenu;  // root menu, representing entire menu bar
+  bool mNeedsRebuild;
+  ApplicationMenuDelegate* mApplicationMenuDelegate;
+};
+
+#endif  // nsMenuBarX_h_
diff --git a/widget/cocoa/nsMenuBarX.mm b/widget/cocoa/nsMenuBarX.mm
new file mode 100644
index 0000000000..9865fc196d
--- /dev/null
+++ b/widget/cocoa/nsMenuBarX.mm
@@ -0,0 +1,1169 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <objc/objc-runtime.h>
+
+#include "nsMenuBarX.h"
+#include "nsMenuX.h"
+#include "nsMenuItemX.h"
+#include "nsMenuUtilsX.h"
+#include "nsCocoaUtils.h"
+#include "nsChildView.h"
+
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "nsGkAtoms.h"
+#include "nsObjCExceptions.h"
+#include "nsThreadUtils.h"
+
+#include "nsIContent.h"
+#include "nsIWidget.h"
+#include "mozilla/dom/Document.h"
+#include "nsIAppStartup.h"
+#include "nsIStringBundle.h"
+#include "nsToolkitCompsCID.h"
+
+#include "mozilla/Components.h"
+#include "mozilla/dom/Element.h"
+
+using namespace mozilla;
+using mozilla::dom::Element;
+
+NativeMenuItemTarget* nsMenuBarX::sNativeEventTarget = nil;
+nsMenuBarX* nsMenuBarX::sLastGeckoMenuBarPainted = nullptr;
+NSMenu* sApplicationMenu = nil;
+BOOL sApplicationMenuIsFallback = NO;
+BOOL gSomeMenuBarPainted = NO;
+
+// defined in nsCocoaWindow.mm.
+extern BOOL sTouchBarIsInitialized;
+
+// We keep references to the first quit and pref item content nodes we find,
+// which will be from the hidden window. We use these when the document for the
+// current window does not have a quit or pref item. We don't need strong refs
+// here because these items are always strong ref'd by their owning menu bar
+// (instance variable).
+static nsIContent* sAboutItemContent = nullptr;
+static nsIContent* sPrefItemContent = nullptr;
+static nsIContent* sAccountItemContent = nullptr;
+static nsIContent* sQuitItemContent = nullptr;
+
+//
+// ApplicationMenuDelegate Objective-C class
+//
+
+@implementation ApplicationMenuDelegate
+
+- (id)initWithApplicationMenu:(nsMenuBarX*)aApplicationMenu {
+  if ((self = [super init])) {
+    mApplicationMenu = aApplicationMenu;
+  }
+  return self;
+}
+
+- (void)menuWillOpen:(NSMenu*)menu {
+  mApplicationMenu->ApplicationMenuOpened();
+}
+
+- (void)menuDidClose:(NSMenu*)menu {
+}
+
+@end
+
+nsMenuBarX::nsMenuBarX(mozilla::dom::Element* aElement)
+    : mNeedsRebuild(false), mApplicationMenuDelegate(nil) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  mMenuGroupOwner = new nsMenuGroupOwnerX(aElement, this);
+  mMenuGroupOwner->RegisterForLocaleChanges();
+  mNativeMenu = [[GeckoNSMenu alloc] initWithTitle:@"MainMenuBar"];
+
+  mContent = aElement;
+
+  if (mContent) {
+    AquifyMenuBar();
+    mMenuGroupOwner->RegisterForContentChanges(mContent, this);
+    ConstructNativeMenus();
+  } else {
+    ConstructFallbackNativeMenus();
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+nsMenuBarX::~nsMenuBarX() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  if (nsMenuBarX::sLastGeckoMenuBarPainted == this) {
+    nsMenuBarX::sLastGeckoMenuBarPainted = nullptr;
+  }
+
+  // the quit/pref items of a random window might have been used if there was no
+  // hidden window, thus we need to invalidate the weak references.
+  if (sAboutItemContent == mAboutItemContent) {
+    sAboutItemContent = nullptr;
+  }
+  if (sQuitItemContent == mQuitItemContent) {
+    sQuitItemContent = nullptr;
+  }
+  if (sPrefItemContent == mPrefItemContent) {
+    sPrefItemContent = nullptr;
+  }
+  if (sAccountItemContent == mAccountItemContent) {
+    sAccountItemContent = nullptr;
+  }
+
+  mMenuGroupOwner->UnregisterForLocaleChanges();
+
+  // make sure we unregister ourselves as a content observer
+  if (mContent) {
+    mMenuGroupOwner->UnregisterForContentChanges(mContent);
+  }
+
+  for (nsMenuX* menu : mMenuArray) {
+    menu->DetachFromGroupOwnerRecursive();
+    menu->DetachFromParent();
+  }
+
+  if (mApplicationMenuDelegate) {
+    [mApplicationMenuDelegate release];
+  }
+
+  [mNativeMenu release];
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuBarX::ConstructNativeMenus() {
+  for (nsIContent* menuContent = mContent->GetFirstChild(); menuContent;
+       menuContent = menuContent->GetNextSibling()) {
+    if (menuContent->IsXULElement(nsGkAtoms::menu)) {
+      InsertMenuAtIndex(
+          MakeRefPtr<nsMenuX>(this, mMenuGroupOwner, menuContent->AsElement()),
+          GetMenuCount());
+    }
+  }
+}
+
+void nsMenuBarX::ConstructFallbackNativeMenus() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  if (sApplicationMenu) {
+    // Menu has already been built.
+    return;
+  }
+
+  nsCOMPtr<nsIStringBundle> stringBundle;
+
+  nsCOMPtr<nsIStringBundleService> bundleSvc =
+      do_GetService(NS_STRINGBUNDLE_CONTRACTID);
+  bundleSvc->CreateBundle("chrome://global/locale/fallbackMenubar.properties",
+                          getter_AddRefs(stringBundle));
+
+  if (!stringBundle) {
+    return;
+  }
+
+  nsAutoString labelUTF16;
+  nsAutoString keyUTF16;
+
+  const char* labelProp = "quitMenuitem.label";
+  const char* keyProp = "quitMenuitem.key";
+
+  stringBundle->GetStringFromName(labelProp, labelUTF16);
+  stringBundle->GetStringFromName(keyProp, keyUTF16);
+
+  NSString* labelStr =
+      [NSString stringWithUTF8String:NS_ConvertUTF16toUTF8(labelUTF16).get()];
+  NSString* keyStr =
+      [NSString stringWithUTF8String:NS_ConvertUTF16toUTF8(keyUTF16).get()];
+
+  if (!nsMenuBarX::sNativeEventTarget) {
+    nsMenuBarX::sNativeEventTarget = [[NativeMenuItemTarget alloc] init];
+  }
+
+  sApplicationMenu = [[[[NSApp mainMenu] itemAtIndex:0] submenu] retain];
+  if (!mApplicationMenuDelegate) {
+    mApplicationMenuDelegate =
+        [[ApplicationMenuDelegate alloc] initWithApplicationMenu:this];
+  }
+  sApplicationMenu.delegate = mApplicationMenuDelegate;
+  NSMenuItem* quitMenuItem =
+      [[[NSMenuItem alloc] initWithTitle:labelStr
+                                  action:@selector(menuItemHit:)
+                           keyEquivalent:keyStr] autorelease];
+  quitMenuItem.target = nsMenuBarX::sNativeEventTarget;
+  quitMenuItem.tag = eCommand_ID_Quit;
+  [sApplicationMenu addItem:quitMenuItem];
+  sApplicationMenuIsFallback = YES;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+uint32_t nsMenuBarX::GetMenuCount() { return mMenuArray.Length(); }
+
+bool nsMenuBarX::MenuContainsAppMenu() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  return (mNativeMenu.numberOfItems > 0 &&
+          [mNativeMenu itemAtIndex:0].submenu == sApplicationMenu);
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuBarX::InsertMenuAtIndex(RefPtr<nsMenuX>&& aMenu, uint32_t aIndex) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // If we've only yet created a fallback global Application menu (using
+  // ContructFallbackNativeMenus()), destroy it before recreating it properly.
+  if (sApplicationMenu && sApplicationMenuIsFallback) {
+    ResetNativeApplicationMenu();
+  }
+  // If we haven't created a global Application menu yet, do it.
+  if (!sApplicationMenu) {
+    CreateApplicationMenu(aMenu.get());
+
+    // Hook the new Application menu up to the menu bar.
+    NSMenu* mainMenu = NSApp.mainMenu;
+    NS_ASSERTION(
+        mainMenu.numberOfItems > 0,
+        "Main menu does not have any items, something is terribly wrong!");
+    [mainMenu itemAtIndex:0].submenu = sApplicationMenu;
+  }
+
+  // add menu to array that owns our menus
+  mMenuArray.InsertElementAt(aIndex, aMenu);
+
+  // hook up submenus
+  RefPtr<nsIContent> menuContent = aMenu->Content();
+  if (menuContent->GetChildCount() > 0 &&
+      !nsMenuUtilsX::NodeIsHiddenOrCollapsed(menuContent)) {
+    MenuChildChangedVisibility(MenuChild(aMenu), true);
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuBarX::RemoveMenuAtIndex(uint32_t aIndex) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  if (mMenuArray.Length() <= aIndex) {
+    NS_ERROR("Attempting submenu removal with bad index!");
+    return;
+  }
+
+  RefPtr<nsMenuX> menu = mMenuArray[aIndex];
+  mMenuArray.RemoveElementAt(aIndex);
+
+  menu->DetachFromGroupOwnerRecursive();
+  menu->DetachFromParent();
+
+  // Our native menu and our internal menu object array might be out of sync.
+  // This happens, for example, when a submenu is hidden. Because of this we
+  // should not assume that a native submenu is hooked up.
+  NSMenuItem* nativeMenuItem = menu->NativeNSMenuItem();
+  int nativeMenuItemIndex = [mNativeMenu indexOfItem:nativeMenuItem];
+  if (nativeMenuItemIndex != -1) {
+    [mNativeMenu removeItemAtIndex:nativeMenuItemIndex];
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuBarX::ObserveAttributeChanged(mozilla::dom::Document* aDocument,
+                                         nsIContent* aContent,
+                                         nsAtom* aAttribute) {}
+
+void nsMenuBarX::ObserveContentRemoved(mozilla::dom::Document* aDocument,
+                                       nsIContent* aContainer,
+                                       nsIContent* aChild,
+                                       nsIContent* aPreviousSibling) {
+  nsINode* parent = NODE_FROM(aContainer, aDocument);
+  MOZ_ASSERT(parent);
+  const Maybe<uint32_t> index = parent->ComputeIndexOf(aPreviousSibling);
+  MOZ_ASSERT(*index != UINT32_MAX);
+  RemoveMenuAtIndex(index.isSome() ? *index + 1u : 0u);
+}
+
+void nsMenuBarX::ObserveContentInserted(mozilla::dom::Document* aDocument,
+                                        nsIContent* aContainer,
+                                        nsIContent* aChild) {
+  InsertMenuAtIndex(MakeRefPtr<nsMenuX>(this, mMenuGroupOwner, aChild),
+                    aContainer->ComputeIndexOf(aChild).valueOr(UINT32_MAX));
+}
+
+void nsMenuBarX::ForceUpdateNativeMenuAt(const nsAString& aIndexString) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  NSString* locationString =
+      [NSString stringWithCharacters:reinterpret_cast<const unichar*>(
+                                         aIndexString.BeginReading())
+                              length:aIndexString.Length()];
+  NSArray* indexes = [locationString componentsSeparatedByString:@"|"];
+  unsigned int indexCount = indexes.count;
+  if (indexCount == 0) {
+    return;
+  }
+
+  RefPtr<nsMenuX> currentMenu = nullptr;
+  int targetIndex = [[indexes objectAtIndex:0] intValue];
+  int visible = 0;
+  uint32_t length = mMenuArray.Length();
+  // first find a menu in the menu bar
+  for (unsigned int i = 0; i < length; i++) {
+    RefPtr<nsMenuX> menu = mMenuArray[i];
+    if (!nsMenuUtilsX::NodeIsHiddenOrCollapsed(menu->Content())) {
+      visible++;
+      if (visible == (targetIndex + 1)) {
+        currentMenu = std::move(menu);
+        break;
+      }
+    }
+  }
+
+  if (!currentMenu) {
+    return;
+  }
+
+  // fake open/close to cause lazy update to happen so submenus populate
+  currentMenu->MenuOpened();
+  currentMenu->MenuClosed();
+
+  // now find the correct submenu
+  for (unsigned int i = 1; currentMenu && i < indexCount; i++) {
+    targetIndex = [[indexes objectAtIndex:i] intValue];
+    visible = 0;
+    length = currentMenu->GetItemCount();
+    for (unsigned int j = 0; j < length; j++) {
+      Maybe<nsMenuX::MenuChild> targetMenu = currentMenu->GetItemAt(j);
+      if (!targetMenu) {
+        return;
+      }
+      RefPtr<nsIContent> content = targetMenu->match(
+          [](const RefPtr<nsMenuX>& aMenu) { return aMenu->Content(); },
+          [](const RefPtr<nsMenuItemX>& aMenuItem) {
+            return aMenuItem->Content();
+          });
+      if (!nsMenuUtilsX::NodeIsHiddenOrCollapsed(content)) {
+        visible++;
+        if (targetMenu->is<RefPtr<nsMenuX>>() && visible == (targetIndex + 1)) {
+          currentMenu = targetMenu->as<RefPtr<nsMenuX>>();
+          // fake open/close to cause lazy update to happen
+          currentMenu->MenuOpened();
+          currentMenu->MenuClosed();
+          break;
+        }
+      }
+    }
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+// Calling this forces a full reload of the menu system, reloading all native
+// menus and their items.
+// Without this testing is hard because changes to the DOM affect the native
+// menu system lazily.
+void nsMenuBarX::ForceNativeMenuReload() {
+  // tear down everything
+  while (GetMenuCount() > 0) {
+    RemoveMenuAtIndex(0);
+  }
+
+  // construct everything
+  ConstructNativeMenus();
+}
+
+nsMenuX* nsMenuBarX::GetMenuAt(uint32_t aIndex) {
+  if (mMenuArray.Length() <= aIndex) {
+    NS_ERROR("Requesting menu at invalid index!");
+    return nullptr;
+  }
+  return mMenuArray[aIndex].get();
+}
+
+nsMenuX* nsMenuBarX::GetXULHelpMenu() {
+  // The Help menu is usually (always?) the last one, so we start there and
+  // count back.
+  for (int32_t i = GetMenuCount() - 1; i >= 0; --i) {
+    nsMenuX* aMenu = GetMenuAt(i);
+    if (aMenu && nsMenuX::IsXULHelpMenu(aMenu->Content())) {
+      return aMenu;
+    }
+  }
+  return nil;
+}
+
+// On SnowLeopard and later we must tell the OS which is our Help menu.
+// Otherwise it will only add Spotlight for Help (the Search item) to our
+// Help menu if its label/title is "Help" -- i.e. if the menu is in English.
+// This resolves bugs 489196 and 539317.
+void nsMenuBarX::SetSystemHelpMenu() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  nsMenuX* xulHelpMenu = GetXULHelpMenu();
+  if (xulHelpMenu) {
+    NSMenu* helpMenu = xulHelpMenu->NativeNSMenu();
+    if (helpMenu) {
+      NSApp.helpMenu = helpMenu;
+    }
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+// macOS is adding some (currently 3) hidden menu items every time that
+// `NSApp.mainMenu` is set, but never removes them. This ultimately causes a
+// significant slowdown when switching between windows because the number of
+// items in `NSApp.mainMenu` is growing without bounds.
+//
+// The known hidden, problematic menu items are associated with the following
+// menus:
+//   - Start Dictation...
+//   - Emoji & Symbols
+//
+// Removing these items before setting `NSApp.mainMenu` prevents this slowdown.
+// See bug 1808223.
+static bool RemoveProblematicMenuItems(NSMenu* aMenu) {
+  uint8_t problematicMenuItemCount = 3;
+  NSMutableArray* itemsToRemove =
+      [NSMutableArray arrayWithCapacity:problematicMenuItemCount];
+
+  for (NSInteger i = 0; i < aMenu.numberOfItems; i++) {
+    NSMenuItem* item = [aMenu itemAtIndex:i];
+
+    if (item.hidden &&
+        (item.action == @selector(startDictation:) ||
+         item.action == @selector(orderFrontCharacterPalette:))) {
+      [itemsToRemove addObject:@(i)];
+    }
+
+    if (item.hasSubmenu && RemoveProblematicMenuItems(item.submenu)) {
+      return true;
+    }
+  }
+
+  bool didRemoveItems = false;
+  for (NSNumber* index in [itemsToRemove reverseObjectEnumerator]) {
+    [aMenu removeItemAtIndex:index.integerValue];
+    didRemoveItems = true;
+  }
+
+  return didRemoveItems;
+}
+
+nsresult nsMenuBarX::Paint() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // Don't try to optimize anything in this painting by checking
+  // sLastGeckoMenuBarPainted because the menubar can be manipulated by
+  // native dialogs and sheet code and other things besides this paint method.
+
+  // We have to keep the same menu item for the Application menu so we keep
+  // passing it along.
+  NSMenu* outgoingMenu = [NSApp.mainMenu retain];
+  NS_ASSERTION(
+      outgoingMenu.numberOfItems > 0,
+      "Main menu does not have any items, something is terribly wrong!");
+
+  NSMenuItem* appMenuItem = [[outgoingMenu itemAtIndex:0] retain];
+  [outgoingMenu removeItemAtIndex:0];
+  if (appMenuItem) {
+    [mNativeMenu insertItem:appMenuItem atIndex:0];
+  }
+  [appMenuItem release];
+  [outgoingMenu release];
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  RemoveProblematicMenuItems(mNativeMenu);
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // Set menu bar and event target.
+  NSApp.mainMenu = mNativeMenu;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  SetSystemHelpMenu();
+  nsMenuBarX::sLastGeckoMenuBarPainted = this;
+
+  gSomeMenuBarPainted = YES;
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+/* static */
+void nsMenuBarX::ResetNativeApplicationMenu() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  [sApplicationMenu removeAllItems];
+  [sApplicationMenu release];
+  sApplicationMenu = nil;
+  sApplicationMenuIsFallback = NO;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuBarX::SetNeedsRebuild() { mNeedsRebuild = true; }
+
+void nsMenuBarX::ApplicationMenuOpened() {
+  if (mNeedsRebuild) {
+    if (!mMenuArray.IsEmpty()) {
+      ResetNativeApplicationMenu();
+      CreateApplicationMenu(mMenuArray[0].get());
+    }
+    mNeedsRebuild = false;
+  }
+}
+
+bool nsMenuBarX::PerformKeyEquivalent(NSEvent* aEvent) {
+  return [mNativeMenu performSuperKeyEquivalent:aEvent];
+}
+
+void nsMenuBarX::MenuChildChangedVisibility(const MenuChild& aChild,
+                                            bool aIsVisible) {
+  MOZ_RELEASE_ASSERT(aChild.is<RefPtr<nsMenuX>>(),
+                     "nsMenuBarX only has nsMenuX children");
+  const RefPtr<nsMenuX>& child = aChild.as<RefPtr<nsMenuX>>();
+  NSMenuItem* item = child->NativeNSMenuItem();
+  if (aIsVisible) {
+    NSInteger insertionPoint = CalculateNativeInsertionPoint(child);
+    [mNativeMenu insertItem:item atIndex:insertionPoint];
+  } else if ([mNativeMenu indexOfItem:item] != -1) {
+    [mNativeMenu removeItem:item];
+  }
+}
+
+NSInteger nsMenuBarX::CalculateNativeInsertionPoint(nsMenuX* aChild) {
+  NSInteger insertionPoint = MenuContainsAppMenu() ? 1 : 0;
+  for (auto& currMenu : mMenuArray) {
+    if (currMenu == aChild) {
+      return insertionPoint;
+    }
+    // Only count items that are inside a menu.
+    // XXXmstange Not sure what would cause free-standing items. Maybe for
+    // collapsed/hidden menus? In that case, an nsMenuX::IsVisible() method
+    // would be better.
+    if (currMenu->NativeNSMenuItem().menu) {
+      insertionPoint++;
+    }
+  }
+  return insertionPoint;
+}
+
+// Hide the item in the menu by setting the 'hidden' attribute. Returns it so
+// the caller can hang onto it if they so choose.
+RefPtr<Element> nsMenuBarX::HideItem(mozilla::dom::Document* aDocument,
+                                     const nsAString& aID) {
+  RefPtr<Element> menuElement = aDocument->GetElementById(aID);
+  if (menuElement) {
+    menuElement->SetAttr(kNameSpaceID_None, nsGkAtoms::hidden, u"true"_ns,
+                         false);
+  }
+  return menuElement;
+}
+
+// Do what is necessary to conform to the Aqua guidelines for menus.
+void nsMenuBarX::AquifyMenuBar() {
+  RefPtr<mozilla::dom::Document> domDoc = mContent->GetComposedDoc();
+  if (domDoc) {
+    // remove the "About..." item and its separator
+    HideItem(domDoc, u"aboutSeparator"_ns);
+    mAboutItemContent = HideItem(domDoc, u"aboutName"_ns);
+    if (!sAboutItemContent) {
+      sAboutItemContent = mAboutItemContent;
+    }
+
+    // remove quit item and its separator
+    HideItem(domDoc, u"menu_FileQuitSeparator"_ns);
+    mQuitItemContent = HideItem(domDoc, u"menu_FileQuitItem"_ns);
+    if (!sQuitItemContent) {
+      sQuitItemContent = mQuitItemContent;
+    }
+
+    // remove prefs item and its separator, but save off the pref content node
+    // so we can invoke its command later.
+    HideItem(domDoc, u"menu_PrefsSeparator"_ns);
+    mPrefItemContent = HideItem(domDoc, u"menu_preferences"_ns);
+    if (!sPrefItemContent) {
+      sPrefItemContent = mPrefItemContent;
+    }
+
+    // remove Account Settings item.
+    mAccountItemContent = HideItem(domDoc, u"menu_accountmgr"_ns);
+    if (!sAccountItemContent) {
+      sAccountItemContent = mAccountItemContent;
+    }
+
+    // hide items that we use for the Application menu
+    HideItem(domDoc, u"menu_mac_services"_ns);
+    HideItem(domDoc, u"menu_mac_hide_app"_ns);
+    HideItem(domDoc, u"menu_mac_hide_others"_ns);
+    HideItem(domDoc, u"menu_mac_show_all"_ns);
+    HideItem(domDoc, u"menu_mac_touch_bar"_ns);
+  }
+}
+
+// for creating menu items destined for the Application menu
+NSMenuItem* nsMenuBarX::CreateNativeAppMenuItem(nsMenuX* aMenu,
+                                                const nsAString& aNodeID,
+                                                SEL aAction, int aTag,
+                                                NativeMenuItemTarget* aTarget) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  RefPtr<mozilla::dom::Document> doc = aMenu->Content()->GetUncomposedDoc();
+  if (!doc) {
+    return nil;
+  }
+
+  RefPtr<mozilla::dom::Element> menuItem = doc->GetElementById(aNodeID);
+  if (!menuItem) {
+    return nil;
+  }
+
+  // Check collapsed rather than hidden since the app menu items are always
+  // hidden in AquifyMenuBar.
+  if (menuItem->AttrValueIs(kNameSpaceID_None, nsGkAtoms::collapsed,
+                            nsGkAtoms::_true, eCaseMatters)) {
+    return nil;
+  }
+
+  // Get information from the gecko menu item
+  nsAutoString label;
+  nsAutoString modifiers;
+  nsAutoString key;
+  menuItem->GetAttr(nsGkAtoms::label, label);
+  menuItem->GetAttr(nsGkAtoms::modifiers, modifiers);
+  menuItem->GetAttr(nsGkAtoms::key, key);
+
+  // Get more information about the key equivalent. Start by
+  // finding the key node we need.
+  NSString* keyEquiv = nil;
+  unsigned int macKeyModifiers = 0;
+  if (!key.IsEmpty()) {
+    RefPtr<Element> keyElement = doc->GetElementById(key);
+    if (keyElement) {
+      // first grab the key equivalent character
+      nsAutoString keyChar(u" "_ns);
+      keyElement->GetAttr(nsGkAtoms::key, keyChar);
+      if (!keyChar.EqualsLiteral(" ")) {
+        keyEquiv = [[NSString
+            stringWithCharacters:reinterpret_cast<const unichar*>(keyChar.get())
+                          length:keyChar.Length()] lowercaseString];
+      }
+      // now grab the key equivalent modifiers
+      nsAutoString modifiersStr;
+      keyElement->GetAttr(nsGkAtoms::modifiers, modifiersStr);
+      uint8_t geckoModifiers =
+          nsMenuUtilsX::GeckoModifiersForNodeAttribute(modifiersStr);
+      macKeyModifiers =
+          nsMenuUtilsX::MacModifiersForGeckoModifiers(geckoModifiers);
+    }
+  }
+  // get the label into NSString-form
+  NSString* labelString = [NSString
+      stringWithCharacters:reinterpret_cast<const unichar*>(label.get())
+                    length:label.Length()];
+
+  if (!labelString) {
+    labelString = @"";
+  }
+  if (!keyEquiv) {
+    keyEquiv = @"";
+  }
+
+  // put together the actual NSMenuItem
+  NSMenuItem* newMenuItem = [[NSMenuItem alloc] initWithTitle:labelString
+                                                       action:aAction
+                                                keyEquivalent:keyEquiv];
+
+  newMenuItem.tag = aTag;
+  newMenuItem.target = aTarget;
+  newMenuItem.keyEquivalentModifierMask = macKeyModifiers;
+  newMenuItem.representedObject = mMenuGroupOwner->GetRepresentedObject();
+
+  return newMenuItem;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+// build the Application menu shared by all menu bars
+void nsMenuBarX::CreateApplicationMenu(nsMenuX* aMenu) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // At this point, the application menu is the application menu from
+  // the nib in cocoa widgets. We do not have a way to create an application
+  // menu manually, so we grab the one from the nib and use that.
+  sApplicationMenu = [[NSApp.mainMenu itemAtIndex:0].submenu retain];
+
+  /*
+    We support the following menu items here:
+
+    Menu Item                DOM Node ID             Notes
+
+    ========================
+    = About This App       = <- aboutName
+    ========================
+    = Preferences...       = <- menu_preferences
+    = Account Settings     = <- menu_accountmgr      Only on Thunderbird
+    ========================
+    = Services     >       = <- menu_mac_services    <- (do not define key
+    equivalent)
+    ========================
+    = Hide App             = <- menu_mac_hide_app
+    = Hide Others          = <- menu_mac_hide_others
+    = Show All             = <- menu_mac_show_all
+    ========================
+    = Customize Touch Bar… = <- menu_mac_touch_bar
+    ========================
+    = Quit                 = <- menu_FileQuitItem
+    ========================
+
+    If any of them are ommitted from the application's DOM, we just don't add
+    them. We always add a "Quit" item, but if an app developer does not provide
+    a DOM node with the right ID for the Quit item, we add it in English. App
+    developers need only add each node with a label and a key equivalent (if
+    they want one). Other attributes are optional. Like so:
+
+    <menuitem id="menu_preferences"
+           label="&preferencesCmdMac.label;"
+             key="open_prefs_key"/>
+
+    We need to use this system for localization purposes, until we have a better
+    way to define the Application menu to be used on Mac OS X.
+  */
+
+  if (sApplicationMenu) {
+    if (!mApplicationMenuDelegate) {
+      mApplicationMenuDelegate =
+          [[ApplicationMenuDelegate alloc] initWithApplicationMenu:this];
+    }
+    sApplicationMenu.delegate = mApplicationMenuDelegate;
+
+    // This code reads attributes we are going to care about from the DOM
+    // elements
+
+    NSMenuItem* itemBeingAdded = nil;
+    BOOL addAboutSeparator = FALSE;
+    BOOL addPrefsSeparator = FALSE;
+
+    // Add the About menu item
+    itemBeingAdded = CreateNativeAppMenuItem(
+        aMenu, u"aboutName"_ns, @selector(menuItemHit:), eCommand_ID_About,
+        nsMenuBarX::sNativeEventTarget);
+    if (itemBeingAdded) {
+      [sApplicationMenu addItem:itemBeingAdded];
+      [itemBeingAdded release];
+      itemBeingAdded = nil;
+
+      addAboutSeparator = TRUE;
+    }
+
+    // Add separator if either the About item or software update item exists
+    if (addAboutSeparator) {
+      [sApplicationMenu addItem:[NSMenuItem separatorItem]];
+    }
+
+    // Add the Preferences menu item
+    itemBeingAdded = CreateNativeAppMenuItem(
+        aMenu, u"menu_preferences"_ns, @selector(menuItemHit:),
+        eCommand_ID_Prefs, nsMenuBarX::sNativeEventTarget);
+    if (itemBeingAdded) {
+      [sApplicationMenu addItem:itemBeingAdded];
+      [itemBeingAdded release];
+      itemBeingAdded = nil;
+
+      addPrefsSeparator = TRUE;
+    }
+
+    // Add the Account Settings menu item. This is Thunderbird only
+    itemBeingAdded = CreateNativeAppMenuItem(
+        aMenu, u"menu_accountmgr"_ns, @selector(menuItemHit:),
+        eCommand_ID_Account, nsMenuBarX::sNativeEventTarget);
+    if (itemBeingAdded) {
+      [sApplicationMenu addItem:itemBeingAdded];
+      [itemBeingAdded release];
+      itemBeingAdded = nil;
+    }
+
+    // Add separator after Preferences menu
+    if (addPrefsSeparator) {
+      [sApplicationMenu addItem:[NSMenuItem separatorItem]];
+    }
+
+    // Add Services menu item
+    itemBeingAdded =
+        CreateNativeAppMenuItem(aMenu, u"menu_mac_services"_ns, nil, 0, nil);
+    if (itemBeingAdded) {
+      [sApplicationMenu addItem:itemBeingAdded];
+
+      // set this menu item up as the Mac OS X Services menu
+      NSMenu* servicesMenu = [[GeckoServicesNSMenu alloc] initWithTitle:@""];
+      itemBeingAdded.submenu = servicesMenu;
+      NSApp.servicesMenu = servicesMenu;
+
+      [itemBeingAdded release];
+      itemBeingAdded = nil;
+
+      // Add separator after Services menu
+      [sApplicationMenu addItem:[NSMenuItem separatorItem]];
+    }
+
+    BOOL addHideShowSeparator = FALSE;
+
+    // Add menu item to hide this application
+    itemBeingAdded = CreateNativeAppMenuItem(
+        aMenu, u"menu_mac_hide_app"_ns, @selector(menuItemHit:),
+        eCommand_ID_HideApp, nsMenuBarX::sNativeEventTarget);
+    if (itemBeingAdded) {
+      [sApplicationMenu addItem:itemBeingAdded];
+      [itemBeingAdded release];
+      itemBeingAdded = nil;
+
+      addHideShowSeparator = TRUE;
+    }
+
+    // Add menu item to hide other applications
+    itemBeingAdded = CreateNativeAppMenuItem(
+        aMenu, u"menu_mac_hide_others"_ns, @selector(menuItemHit:),
+        eCommand_ID_HideOthers, nsMenuBarX::sNativeEventTarget);
+    if (itemBeingAdded) {
+      [sApplicationMenu addItem:itemBeingAdded];
+      [itemBeingAdded release];
+      itemBeingAdded = nil;
+
+      addHideShowSeparator = TRUE;
+    }
+
+    // Add menu item to show all applications
+    itemBeingAdded = CreateNativeAppMenuItem(
+        aMenu, u"menu_mac_show_all"_ns, @selector(menuItemHit:),
+        eCommand_ID_ShowAll, nsMenuBarX::sNativeEventTarget);
+    if (itemBeingAdded) {
+      [sApplicationMenu addItem:itemBeingAdded];
+      [itemBeingAdded release];
+      itemBeingAdded = nil;
+
+      addHideShowSeparator = TRUE;
+    }
+
+    // Add a separator after the hide/show menus if at least one exists
+    if (addHideShowSeparator) {
+      [sApplicationMenu addItem:[NSMenuItem separatorItem]];
+    }
+
+    BOOL addTouchBarSeparator = NO;
+
+    // Add Touch Bar customization menu item.
+    itemBeingAdded = CreateNativeAppMenuItem(
+        aMenu, u"menu_mac_touch_bar"_ns, @selector(menuItemHit:),
+        eCommand_ID_TouchBar, nsMenuBarX::sNativeEventTarget);
+
+    if (itemBeingAdded) {
+      [sApplicationMenu addItem:itemBeingAdded];
+      // We hide the menu item on Macs that don't have a Touch Bar.
+      if (!sTouchBarIsInitialized) {
+        [itemBeingAdded setHidden:YES];
+      } else {
+        addTouchBarSeparator = YES;
+      }
+      [itemBeingAdded release];
+      itemBeingAdded = nil;
+    }
+
+    // Add a separator after the Touch Bar menu item if it exists
+    if (addTouchBarSeparator) {
+      [sApplicationMenu addItem:[NSMenuItem separatorItem]];
+    }
+
+    // Add quit menu item
+    itemBeingAdded = CreateNativeAppMenuItem(
+        aMenu, u"menu_FileQuitItem"_ns, @selector(menuItemHit:),
+        eCommand_ID_Quit, nsMenuBarX::sNativeEventTarget);
+    if (itemBeingAdded) {
+      [sApplicationMenu addItem:itemBeingAdded];
+      [itemBeingAdded release];
+      itemBeingAdded = nil;
+    } else {
+      // the current application does not have a DOM node for "Quit". Add one
+      // anyway, in English.
+      NSMenuItem* defaultQuitItem =
+          [[[NSMenuItem alloc] initWithTitle:@"Quit"
+                                      action:@selector(menuItemHit:)
+                               keyEquivalent:@"q"] autorelease];
+      defaultQuitItem.target = nsMenuBarX::sNativeEventTarget;
+      defaultQuitItem.tag = eCommand_ID_Quit;
+      [sApplicationMenu addItem:defaultQuitItem];
+    }
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+//
+// Objective-C class used to allow us to have keyboard commands
+// look like they are doing something but actually do nothing.
+// We allow mouse actions to work normally.
+//
+
+// Controls whether or not native menu items should invoke their commands.
+static BOOL gMenuItemsExecuteCommands = YES;
+
+@implementation GeckoNSMenu
+
+// Keyboard commands should not cause menu items to invoke their
+// commands when there is a key window because we'd rather send
+// the keyboard command to the window. We still have the menus
+// go through the mechanics so they'll give the proper visual
+// feedback.
+- (BOOL)performKeyEquivalent:(NSEvent*)aEvent {
+  // We've noticed that Mac OS X expects this check in subclasses before
+  // calling NSMenu's "performKeyEquivalent:".
+  //
+  // There is no case in which we'd need to do anything or return YES
+  // when we have no items so we can just do this check first.
+  if (self.numberOfItems <= 0) {
+    return NO;
+  }
+
+  NSWindow* keyWindow = NSApp.keyWindow;
+
+  // If there is no key window then just behave normally. This
+  // probably means that this menu is associated with Gecko's
+  // hidden window.
+  if (!keyWindow) {
+    return [super performKeyEquivalent:aEvent];
+  }
+
+  NSResponder* firstResponder = keyWindow.firstResponder;
+
+  gMenuItemsExecuteCommands = NO;
+  [super performKeyEquivalent:aEvent];
+  gMenuItemsExecuteCommands = YES;  // return to default
+
+  // Return YES if we invoked a command and there is now no key window or we
+  // changed the first responder. In this case we do not want to propagate the
+  // event because we don't want it handled again.
+  if (!NSApp.keyWindow || NSApp.keyWindow.firstResponder != firstResponder) {
+    return YES;
+  }
+
+  // Return NO so that we can handle the event via NSView's "keyDown:".
+  return NO;
+}
+
+- (BOOL)performSuperKeyEquivalent:(NSEvent*)aEvent {
+  return [super performKeyEquivalent:aEvent];
+}
+
+@end
+
+//
+// Objective-C class used as action target for menu items
+//
+
+@implementation NativeMenuItemTarget
+
+// called when some menu item in this menu gets hit
+- (IBAction)menuItemHit:(id)aSender {
+  if (!gMenuItemsExecuteCommands) {
+    return;
+  }
+
+  if (![aSender isKindOfClass:[NSMenuItem class]]) {
+    return;
+  }
+
+  NSMenuItem* nativeMenuItem = (NSMenuItem*)aSender;
+  NSInteger tag = nativeMenuItem.tag;
+
+  nsMenuGroupOwnerX* menuGroupOwner = nullptr;
+  nsMenuBarX* menuBar = nullptr;
+  MOZMenuItemRepresentedObject* representedObject =
+      nativeMenuItem.representedObject;
+
+  if (representedObject) {
+    menuGroupOwner = representedObject.menuGroupOwner;
+    if (!menuGroupOwner) {
+      return;
+    }
+    menuBar = menuGroupOwner->GetMenuBar();
+  }
+
+  // Notify containing menu about the fact that a menu item will be activated.
+  NSMenu* menu = nativeMenuItem.menu;
+  if ([menu.delegate isKindOfClass:[MenuDelegate class]]) {
+    [(MenuDelegate*)menu.delegate menu:menu willActivateItem:nativeMenuItem];
+  }
+
+  // Get the modifier flags and button for this menu item activation. The menu
+  // system does not pass an NSEvent to our action selector, but we can query
+  // the current NSEvent instead. The current NSEvent can be a key event or a
+  // mouseup event, depending on how the menu item is activated.
+  NSEventModifierFlags modifierFlags =
+      NSApp.currentEvent ? NSApp.currentEvent.modifierFlags : 0;
+  mozilla::MouseButton button =
+      NSApp.currentEvent ? nsCocoaUtils::ButtonForEvent(NSApp.currentEvent)
+                         : mozilla::MouseButton::ePrimary;
+
+  // Do special processing if this is for an app-global command.
+  if (tag == eCommand_ID_About) {
+    nsIContent* mostSpecificContent = sAboutItemContent;
+    if (menuBar && menuBar->mAboutItemContent) {
+      mostSpecificContent = menuBar->mAboutItemContent;
+    }
+    nsMenuUtilsX::DispatchCommandTo(mostSpecificContent, modifierFlags, button);
+    return;
+  }
+  if (tag == eCommand_ID_Prefs) {
+    nsIContent* mostSpecificContent = sPrefItemContent;
+    if (menuBar && menuBar->mPrefItemContent) {
+      mostSpecificContent = menuBar->mPrefItemContent;
+    }
+    nsMenuUtilsX::DispatchCommandTo(mostSpecificContent, modifierFlags, button);
+    return;
+  }
+  if (tag == eCommand_ID_Account) {
+    nsIContent* mostSpecificContent = sAccountItemContent;
+    if (menuBar && menuBar->mAccountItemContent) {
+      mostSpecificContent = menuBar->mAccountItemContent;
+    }
+    nsMenuUtilsX::DispatchCommandTo(mostSpecificContent, modifierFlags, button);
+    return;
+  }
+  if (tag == eCommand_ID_HideApp) {
+    [NSApp hide:aSender];
+    return;
+  }
+  if (tag == eCommand_ID_HideOthers) {
+    [NSApp hideOtherApplications:aSender];
+    return;
+  }
+  if (tag == eCommand_ID_ShowAll) {
+    [NSApp unhideAllApplications:aSender];
+    return;
+  }
+  if (tag == eCommand_ID_TouchBar) {
+    [NSApp toggleTouchBarCustomizationPalette:aSender];
+    return;
+  }
+  if (tag == eCommand_ID_Quit) {
+    nsIContent* mostSpecificContent = sQuitItemContent;
+    if (menuBar && menuBar->mQuitItemContent) {
+      mostSpecificContent = menuBar->mQuitItemContent;
+    }
+    // If we have some content for quit we execute it. Otherwise we send a
+    // native app terminate message. If you want to stop a quit from happening,
+    // provide quit content and return the event as unhandled.
+    if (mostSpecificContent) {
+      nsMenuUtilsX::DispatchCommandTo(mostSpecificContent, modifierFlags,
+                                      button);
+    } else {
+      nsCOMPtr<nsIAppStartup> appStartup =
+          mozilla::components::AppStartup::Service();
+      if (appStartup) {
+        bool userAllowedQuit = true;
+        appStartup->Quit(nsIAppStartup::eAttemptQuit, 0, &userAllowedQuit);
+      }
+    }
+    return;
+  }
+
+  // given the commandID, look it up in our hashtable and dispatch to
+  // that menu item.
+  if (menuGroupOwner) {
+    if (RefPtr<nsMenuItemX> menuItem = menuGroupOwner->GetMenuItemForCommandID(
+            static_cast<uint32_t>(tag))) {
+      if (nsMenuUtilsX::gIsSynchronouslyActivatingNativeMenuItemDuringTest) {
+        menuItem->DoCommand(modifierFlags, button);
+      } else if (RefPtr<nsMenuX> menu = menuItem->ParentMenu()) {
+        menu->ActivateItemAfterClosing(std::move(menuItem), modifierFlags,
+                                       button);
+      }
+    }
+  }
+}
+
+@end
+
+// Objective-C class used for menu items on the Services menu to allow Gecko
+// to override their standard behavior in order to stop key equivalents from
+// firing in certain instances. When gMenuItemsExecuteCommands is NO, we return
+// a dummy target and action instead of the actual target and action.
+
+@implementation GeckoServicesNSMenuItem
+
+- (id)target {
+  id realTarget = super.target;
+  if (gMenuItemsExecuteCommands) {
+    return realTarget;
+  }
+  return realTarget ? self : nil;
+}
+
+- (SEL)action {
+  SEL realAction = super.action;
+  if (gMenuItemsExecuteCommands) {
+    return realAction;
+  }
+  return realAction ? @selector(_doNothing:) : nullptr;
+}
+
+- (void)_doNothing:(id)aSender {
+}
+
+@end
+
+// Objective-C class used as the Services menu so that Gecko can override the
+// standard behavior of the Services menu in order to stop key equivalents
+// from firing in certain instances.
+
+@implementation GeckoServicesNSMenu
+
+- (void)addItem:(NSMenuItem*)aNewItem {
+  [self _overrideClassOfMenuItem:aNewItem];
+  [super addItem:aNewItem];
+}
+
+- (NSMenuItem*)addItemWithTitle:(NSString*)aString
+                         action:(SEL)aSelector
+                  keyEquivalent:(NSString*)aKeyEquiv {
+  NSMenuItem* newItem = [super addItemWithTitle:aString
+                                         action:aSelector
+                                  keyEquivalent:aKeyEquiv];
+  [self _overrideClassOfMenuItem:newItem];
+  return newItem;
+}
+
+- (void)insertItem:(NSMenuItem*)aNewItem atIndex:(NSInteger)aIndex {
+  [self _overrideClassOfMenuItem:aNewItem];
+  [super insertItem:aNewItem atIndex:aIndex];
+}
+
+- (NSMenuItem*)insertItemWithTitle:(NSString*)aString
+                            action:(SEL)aSelector
+                     keyEquivalent:(NSString*)aKeyEquiv
+                           atIndex:(NSInteger)aIndex {
+  NSMenuItem* newItem = [super insertItemWithTitle:aString
+                                            action:aSelector
+                                     keyEquivalent:aKeyEquiv
+                                           atIndex:aIndex];
+  [self _overrideClassOfMenuItem:newItem];
+  return newItem;
+}
+
+- (void)_overrideClassOfMenuItem:(NSMenuItem*)aMenuItem {
+  if ([aMenuItem class] == [NSMenuItem class]) {
+    object_setClass(aMenuItem, [GeckoServicesNSMenuItem class]);
+  }
+}
+
+@end
diff --git a/widget/cocoa/nsMenuGroupOwnerX.h b/widget/cocoa/nsMenuGroupOwnerX.h
new file mode 100644
index 0000000000..da859d14f3
--- /dev/null
+++ b/widget/cocoa/nsMenuGroupOwnerX.h
@@ -0,0 +1,102 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsMenuGroupOwnerX_h_
+#define nsMenuGroupOwnerX_h_
+
+#import <Cocoa/Cocoa.h>
+
+#include "mozilla/WeakPtr.h"
+
+#include "nsStubMutationObserver.h"
+#include "nsHashKeys.h"
+#include "nsIObserver.h"
+#include "nsMenuBarX.h"
+#include "nsTHashMap.h"
+#include "nsString.h"
+
+class nsMenuItemX;
+class nsChangeObserver;
+class nsIWidget;
+class nsIContent;
+
+@class MOZMenuItemRepresentedObject;
+
+// Fixed command IDs that work even without a JS listener, for our fallback menu
+// bar. Dynamic command IDs start counting from eCommand_ID_Last.
+enum {
+  eCommand_ID_About = 1,
+  eCommand_ID_Prefs = 2,
+  eCommand_ID_Quit = 3,
+  eCommand_ID_HideApp = 4,
+  eCommand_ID_HideOthers = 5,
+  eCommand_ID_ShowAll = 6,
+  eCommand_ID_Update = 7,
+  eCommand_ID_TouchBar = 8,
+  eCommand_ID_Account = 9,
+  eCommand_ID_Last = 10
+};
+
+// The menu group owner observes DOM mutations, notifies registered
+// nsChangeObservers, and manages command registration. There is one owner per
+// menubar, and one per standalone native menu.
+class nsMenuGroupOwnerX : public nsMultiMutationObserver, public nsIObserver {
+ public:
+  // Both parameters can be null.
+  nsMenuGroupOwnerX(mozilla::dom::Element* aElement,
+                    nsMenuBarX* aMenuBarIfMenuBar);
+
+  void RegisterForContentChanges(nsIContent* aContent,
+                                 nsChangeObserver* aMenuObject);
+  void UnregisterForContentChanges(nsIContent* aContent);
+  uint32_t RegisterForCommand(nsMenuItemX* aMenuItem);
+  void UnregisterCommand(uint32_t aCommandID);
+  nsMenuItemX* GetMenuItemForCommandID(uint32_t aCommandID);
+
+  void RegisterForLocaleChanges();
+  void UnregisterForLocaleChanges();
+
+  // The representedObject that's used for all menu items under this menu group
+  // owner.
+  MOZMenuItemRepresentedObject* GetRepresentedObject() {
+    return mRepresentedObject;
+  }
+
+  // If this is the group owner for a menubar, return the menubar, otherwise
+  // nullptr.
+  nsMenuBarX* GetMenuBar() { return mMenuBar.get(); }
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+  NS_DECL_NSIMUTATIONOBSERVER
+
+ protected:
+  virtual ~nsMenuGroupOwnerX();
+
+  nsChangeObserver* LookupContentChangeObserver(nsIContent* aContent);
+
+  RefPtr<nsIContent> mContent;
+
+  // Unique command id (per menu-bar) to give to next item that asks.
+  uint32_t mCurrentCommandID = eCommand_ID_Last;
+
+  // stores observers for content change notification
+  nsTHashMap<nsPtrHashKey<nsIContent>, nsChangeObserver*>
+      mContentToObserverTable;
+
+  // stores mapping of command IDs to menu objects
+  nsTHashMap<nsUint32HashKey, nsMenuItemX*> mCommandToMenuObjectTable;
+
+  MOZMenuItemRepresentedObject* mRepresentedObject = nil;  // [strong]
+  mozilla::WeakPtr<nsMenuBarX> mMenuBar;
+};
+
+@interface MOZMenuItemRepresentedObject : NSObject
+- (id)initWithMenuGroupOwner:(nsMenuGroupOwnerX*)aMenuGroupOwner;
+- (void)setMenuGroupOwner:(nsMenuGroupOwnerX*)aMenuGroupOwner;
+- (nsMenuGroupOwnerX*)menuGroupOwner;
+@end
+
+#endif  // nsMenuGroupOwner_h_
diff --git a/widget/cocoa/nsMenuGroupOwnerX.mm b/widget/cocoa/nsMenuGroupOwnerX.mm
new file mode 100644
index 0000000000..45d074e12f
--- /dev/null
+++ b/widget/cocoa/nsMenuGroupOwnerX.mm
@@ -0,0 +1,238 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsMenuGroupOwnerX.h"
+#include "nsMenuBarX.h"
+#include "nsMenuX.h"
+#include "nsMenuItemX.h"
+#include "nsMenuUtilsX.h"
+#include "nsCocoaUtils.h"
+#include "nsCocoaWindow.h"
+
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "nsObjCExceptions.h"
+#include "nsThreadUtils.h"
+
+#include "mozilla/dom/Element.h"
+#include "nsIWidget.h"
+#include "mozilla/dom/Document.h"
+
+#include "nsINode.h"
+
+using namespace mozilla;
+
+NS_IMPL_ISUPPORTS(nsMenuGroupOwnerX, nsIObserver, nsIMutationObserver)
+
+nsMenuGroupOwnerX::nsMenuGroupOwnerX(mozilla::dom::Element* aElement,
+                                     nsMenuBarX* aMenuBarIfMenuBar)
+    : mContent(aElement), mMenuBar(aMenuBarIfMenuBar) {
+  mRepresentedObject =
+      [[MOZMenuItemRepresentedObject alloc] initWithMenuGroupOwner:this];
+}
+
+nsMenuGroupOwnerX::~nsMenuGroupOwnerX() {
+  MOZ_ASSERT(mContentToObserverTable.Count() == 0,
+             "have outstanding mutation observers!\n");
+  [mRepresentedObject setMenuGroupOwner:nullptr];
+  [mRepresentedObject release];
+}
+
+//
+// nsIMutationObserver
+//
+
+void nsMenuGroupOwnerX::CharacterDataWillChange(
+    nsIContent* aContent, const CharacterDataChangeInfo&) {}
+
+void nsMenuGroupOwnerX::CharacterDataChanged(nsIContent* aContent,
+                                             const CharacterDataChangeInfo&) {}
+
+void nsMenuGroupOwnerX::ContentAppended(nsIContent* aFirstNewContent) {
+  for (nsIContent* cur = aFirstNewContent; cur; cur = cur->GetNextSibling()) {
+    ContentInserted(cur);
+  }
+}
+
+void nsMenuGroupOwnerX::NodeWillBeDestroyed(nsINode* aNode) {}
+
+void nsMenuGroupOwnerX::AttributeWillChange(dom::Element* aElement,
+                                            int32_t aNameSpaceID,
+                                            nsAtom* aAttribute,
+                                            int32_t aModType) {}
+
+void nsMenuGroupOwnerX::AttributeChanged(dom::Element* aElement,
+                                         int32_t aNameSpaceID,
+                                         nsAtom* aAttribute, int32_t aModType,
+                                         const nsAttrValue* aOldValue) {
+  nsCOMPtr<nsIMutationObserver> kungFuDeathGrip(this);
+  nsChangeObserver* obs = LookupContentChangeObserver(aElement);
+  if (obs) {
+    obs->ObserveAttributeChanged(aElement->OwnerDoc(), aElement, aAttribute);
+  }
+}
+
+void nsMenuGroupOwnerX::ContentRemoved(nsIContent* aChild,
+                                       nsIContent* aPreviousSibling) {
+  nsIContent* container = aChild->GetParent();
+  if (!container) {
+    return;
+  }
+
+  nsCOMPtr<nsIMutationObserver> kungFuDeathGrip(this);
+  nsChangeObserver* obs = LookupContentChangeObserver(container);
+  if (obs) {
+    obs->ObserveContentRemoved(aChild->OwnerDoc(), container, aChild,
+                               aPreviousSibling);
+  } else if (container != mContent) {
+    // We do a lookup on the parent container in case things were removed
+    // under a "menupopup" item. That is basically a wrapper for the contents
+    // of a "menu" node.
+    nsCOMPtr<nsIContent> parent = container->GetParent();
+    if (parent) {
+      obs = LookupContentChangeObserver(parent);
+      if (obs) {
+        obs->ObserveContentRemoved(aChild->OwnerDoc(), container, aChild,
+                                   aPreviousSibling);
+      }
+    }
+  }
+}
+
+void nsMenuGroupOwnerX::ContentInserted(nsIContent* aChild) {
+  nsIContent* container = aChild->GetParent();
+  if (!container) {
+    return;
+  }
+
+  nsCOMPtr<nsIMutationObserver> kungFuDeathGrip(this);
+  nsChangeObserver* obs = LookupContentChangeObserver(container);
+  if (obs) {
+    obs->ObserveContentInserted(aChild->OwnerDoc(), container, aChild);
+  } else if (container != mContent) {
+    // We do a lookup on the parent container in case things were removed
+    // under a "menupopup" item. That is basically a wrapper for the contents
+    // of a "menu" node.
+    nsCOMPtr<nsIContent> parent = container->GetParent();
+    if (parent) {
+      obs = LookupContentChangeObserver(parent);
+      if (obs) {
+        obs->ObserveContentInserted(aChild->OwnerDoc(), container, aChild);
+      }
+    }
+  }
+}
+
+void nsMenuGroupOwnerX::ParentChainChanged(nsIContent* aContent) {}
+
+void nsMenuGroupOwnerX::ARIAAttributeDefaultWillChange(
+    mozilla::dom::Element* aElement, nsAtom* aAttribute, int32_t aModType) {}
+
+void nsMenuGroupOwnerX::ARIAAttributeDefaultChanged(
+    mozilla::dom::Element* aElement, nsAtom* aAttribute, int32_t aModType) {}
+
+// For change management, we don't use a |nsSupportsHashtable| because
+// we know that the lifetime of all these items is bounded by the
+// lifetime of the menubar. No need to add any more strong refs to the
+// picture because the containment hierarchy already uses strong refs.
+void nsMenuGroupOwnerX::RegisterForContentChanges(
+    nsIContent* aContent, nsChangeObserver* aMenuObject) {
+  if (!mContentToObserverTable.Contains(aContent)) {
+    aContent->AddMutationObserver(this);
+  }
+  mContentToObserverTable.InsertOrUpdate(aContent, aMenuObject);
+}
+
+void nsMenuGroupOwnerX::UnregisterForContentChanges(nsIContent* aContent) {
+  if (mContentToObserverTable.Contains(aContent)) {
+    aContent->RemoveMutationObserver(this);
+  }
+  mContentToObserverTable.Remove(aContent);
+}
+
+void nsMenuGroupOwnerX::RegisterForLocaleChanges() {
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    obs->AddObserver(this, "intl:app-locales-changed", false);
+  }
+}
+
+void nsMenuGroupOwnerX::UnregisterForLocaleChanges() {
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    obs->RemoveObserver(this, "intl:app-locales-changed");
+  }
+}
+
+NS_IMETHODIMP
+nsMenuGroupOwnerX::Observe(nsISupports* aSubject, const char* aTopic,
+                           const char16_t* aData) {
+  if (mMenuBar && !strcmp(aTopic, "intl:app-locales-changed")) {
+    // Rebuild the menu with the new locale strings.
+    mMenuBar->SetNeedsRebuild();
+  }
+  return NS_OK;
+}
+
+nsChangeObserver* nsMenuGroupOwnerX::LookupContentChangeObserver(
+    nsIContent* aContent) {
+  nsChangeObserver* result;
+  if (mContentToObserverTable.Get(aContent, &result)) {
+    return result;
+  }
+  return nullptr;
+}
+
+// Given a menu item, creates a unique 4-character command ID and
+// maps it to the item. Returns the id for use by the client.
+uint32_t nsMenuGroupOwnerX::RegisterForCommand(nsMenuItemX* aMenuItem) {
+  // no real need to check for uniqueness. We always start afresh with each
+  // window at 1. Even if we did get close to the reserved Apple command id's,
+  // those don't start until at least '    ', which is integer 538976288. If
+  // we have that many menu items in one window, I think we have other
+  // problems.
+
+  // make id unique
+  ++mCurrentCommandID;
+
+  mCommandToMenuObjectTable.InsertOrUpdate(mCurrentCommandID, aMenuItem);
+
+  return mCurrentCommandID;
+}
+
+// Removes the mapping between the given 4-character command ID
+// and its associated menu item.
+void nsMenuGroupOwnerX::UnregisterCommand(uint32_t aCommandID) {
+  mCommandToMenuObjectTable.Remove(aCommandID);
+}
+
+nsMenuItemX* nsMenuGroupOwnerX::GetMenuItemForCommandID(uint32_t aCommandID) {
+  nsMenuItemX* result;
+  if (mCommandToMenuObjectTable.Get(aCommandID, &result)) {
+    return result;
+  }
+  return nullptr;
+}
+
+@implementation MOZMenuItemRepresentedObject {
+  nsMenuGroupOwnerX*
+      mMenuGroupOwner;  // weak, cleared by nsMenuGroupOwnerX's destructor
+}
+
+- (id)initWithMenuGroupOwner:(nsMenuGroupOwnerX*)aMenuGroupOwner {
+  self = [super init];
+  mMenuGroupOwner = aMenuGroupOwner;
+  return self;
+}
+
+- (void)setMenuGroupOwner:(nsMenuGroupOwnerX*)aMenuGroupOwner {
+  mMenuGroupOwner = aMenuGroupOwner;
+}
+
+- (nsMenuGroupOwnerX*)menuGroupOwner {
+  return mMenuGroupOwner;
+}
+
+@end
diff --git a/widget/cocoa/nsMenuItemIconX.h b/widget/cocoa/nsMenuItemIconX.h
new file mode 100644
index 0000000000..e60e920f9d
--- /dev/null
+++ b/widget/cocoa/nsMenuItemIconX.h
@@ -0,0 +1,70 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Retrieves and displays icons in native menu items on Mac OS X.
+ */
+
+#ifndef nsMenuItemIconX_h_
+#define nsMenuItemIconX_h_
+
+#import <Cocoa/Cocoa.h>
+
+#include "mozilla/widget/IconLoader.h"
+#include "mozilla/WeakPtr.h"
+
+class nsIconLoaderService;
+class nsIURI;
+class nsIContent;
+class nsIPrincipal;
+class imgRequestProxy;
+class nsMenuParentX;
+class nsPresContext;
+
+namespace mozilla {
+class ComputedStyle;
+}
+
+class nsMenuItemIconX final : public mozilla::widget::IconLoader::Listener {
+ public:
+  class Listener {
+   public:
+    virtual void IconUpdated() = 0;
+  };
+
+  explicit nsMenuItemIconX(Listener* aListener);
+  ~nsMenuItemIconX();
+
+  // SetupIcon starts the icon load. Once the icon has loaded,
+  // nsMenuParentX::IconUpdated will be called. The icon image needs to be
+  // retrieved from GetIconImage(). If aContent is an icon-less menuitem,
+  // GetIconImage() will return nil. If it does have an icon, GetIconImage()
+  // will return a transparent placeholder icon during the load and the actual
+  // icon when the load is completed.
+  void SetupIcon(nsIContent* aContent);
+
+  // Implements this method for mozilla::widget::IconLoader::Listener.
+  // Called once the icon load is complete.
+  nsresult OnComplete(imgIContainer* aImage) override;
+
+  // Returns a weak reference to the icon image that is owned by this class. Can
+  // return nil.
+  NSImage* GetIconImage() const { return mIconImage; }
+
+ protected:
+  // Returns whether there should be an icon.
+  bool StartIconLoad(nsIContent* aContent);
+
+  // GetIconURI returns null if the item should not have any icon.
+  already_AddRefed<nsIURI> GetIconURI(nsIContent* aContent);
+
+  Listener* mListener;  // [weak]
+  RefPtr<const mozilla::ComputedStyle> mComputedStyle;
+  mozilla::WeakPtr<nsPresContext> mPresContext;
+  NSImage* mIconImage = nil;  // [strong]
+  RefPtr<mozilla::widget::IconLoader> mIconLoader;
+};
+
+#endif  // nsMenuItemIconX_h_
diff --git a/widget/cocoa/nsMenuItemIconX.mm b/widget/cocoa/nsMenuItemIconX.mm
new file mode 100644
index 0000000000..6749d787de
--- /dev/null
+++ b/widget/cocoa/nsMenuItemIconX.mm
@@ -0,0 +1,173 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Retrieves and displays icons in native menu items on Mac OS X.
+ */
+
+/* exception_defines.h defines 'try' to 'if (true)' which breaks objective-c
+   exceptions and produces errors like: error: unexpected '@' in program'.
+   If we define __EXCEPTIONS exception_defines.h will avoid doing this.
+
+   See bug 666609 for more information.
+
+   We use <limits> to get the libstdc++ version. */
+#include <limits>
+#if __GLIBCXX__ <= 20070719
+#  ifndef __EXCEPTIONS
+#    define __EXCEPTIONS
+#  endif
+#endif
+
+#include "MOZIconHelper.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/DocumentInlines.h"
+#include "nsCocoaUtils.h"
+#include "nsComputedDOMStyle.h"
+#include "nsContentUtils.h"
+#include "nsGkAtoms.h"
+#include "nsIContent.h"
+#include "nsIContentPolicy.h"
+#include "nsMenuItemX.h"
+#include "nsMenuItemIconX.h"
+#include "nsNameSpaceManager.h"
+#include "nsObjCExceptions.h"
+
+using namespace mozilla;
+
+using mozilla::dom::Element;
+using mozilla::widget::IconLoader;
+
+static const uint32_t kIconSize = 16;
+
+nsMenuItemIconX::nsMenuItemIconX(Listener* aListener) : mListener(aListener) {
+  MOZ_COUNT_CTOR(nsMenuItemIconX);
+}
+
+nsMenuItemIconX::~nsMenuItemIconX() {
+  if (mIconLoader) {
+    mIconLoader->Destroy();
+  }
+  if (mIconImage) {
+    [mIconImage release];
+    mIconImage = nil;
+  }
+  MOZ_COUNT_DTOR(nsMenuItemIconX);
+}
+
+void nsMenuItemIconX::SetupIcon(nsIContent* aContent) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  bool shouldHaveIcon = StartIconLoad(aContent);
+  if (!shouldHaveIcon) {
+    // There is no icon for this menu item, as an error occurred while loading
+    // it. An icon might have been set earlier or the place holder icon may have
+    // been set.  Clear it.
+    if (mIconImage) {
+      [mIconImage release];
+      mIconImage = nil;
+    }
+    return;
+  }
+
+  if (!mIconImage) {
+    // Set a placeholder icon, so that the menuitem reserves space for the icon
+    // during the load and there is no sudden shift once the icon finishes
+    // loading.
+    NSSize iconSize = NSMakeSize(kIconSize, kIconSize);
+    mIconImage = [[MOZIconHelper placeholderIconWithSize:iconSize] retain];
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+bool nsMenuItemIconX::StartIconLoad(nsIContent* aContent) {
+  RefPtr<nsIURI> iconURI = GetIconURI(aContent);
+  if (!iconURI) {
+    return false;
+  }
+
+  if (!mIconLoader) {
+    mIconLoader = new IconLoader(this);
+  }
+
+  nsresult rv = mIconLoader->LoadIcon(iconURI, aContent);
+  return NS_SUCCEEDED(rv);
+}
+
+already_AddRefed<nsIURI> nsMenuItemIconX::GetIconURI(nsIContent* aContent) {
+  // First, look at the content node's "image" attribute.
+  nsAutoString imageURIString;
+  bool hasImageAttr =
+      aContent->IsElement() &&
+      aContent->AsElement()->GetAttr(nsGkAtoms::image, imageURIString);
+
+  if (hasImageAttr) {
+    // Use the URL from the image attribute.
+    // If this menu item shouldn't have an icon, the string will be empty,
+    // and NS_NewURI will fail.
+    RefPtr<nsIURI> iconURI;
+    nsresult rv = NS_NewURI(getter_AddRefs(iconURI), imageURIString);
+    if (NS_FAILED(rv)) {
+      return nullptr;
+    }
+    return iconURI.forget();
+  }
+
+  // If the content node has no "image" attribute, get the
+  // "list-style-image" property from CSS.
+  RefPtr<mozilla::dom::Document> document = aContent->GetComposedDoc();
+  if (!document || !aContent->IsElement()) {
+    return nullptr;
+  }
+
+  RefPtr<const ComputedStyle> sc =
+      nsComputedDOMStyle::GetComputedStyle(aContent->AsElement());
+  if (!sc) {
+    return nullptr;
+  }
+
+  RefPtr<nsIURI> iconURI = sc->StyleList()->GetListStyleImageURI();
+  if (!iconURI) {
+    return nullptr;
+  }
+
+  mComputedStyle = std::move(sc);
+  mPresContext = document->GetPresContext();
+
+  return iconURI.forget();
+}
+
+//
+// mozilla::widget::IconLoader::Listener
+//
+
+nsresult nsMenuItemIconX::OnComplete(imgIContainer* aImage) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  if (mIconImage) {
+    [mIconImage release];
+    mIconImage = nil;
+  }
+  RefPtr<nsPresContext> pc = mPresContext.get();
+  mIconImage = [[MOZIconHelper
+      iconImageFromImageContainer:aImage
+                         withSize:NSMakeSize(kIconSize, kIconSize)
+                      presContext:pc
+                    computedStyle:mComputedStyle
+                      scaleFactor:0.0f] retain];
+  mComputedStyle = nullptr;
+  mPresContext = nullptr;
+
+  if (mListener) {
+    mListener->IconUpdated();
+  }
+
+  mIconLoader->Destroy();
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
diff --git a/widget/cocoa/nsMenuItemX.h b/widget/cocoa/nsMenuItemX.h
new file mode 100644
index 0000000000..980105e123
--- /dev/null
+++ b/widget/cocoa/nsMenuItemX.h
@@ -0,0 +1,105 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsMenuItemX_h_
+#define nsMenuItemX_h_
+
+#include "mozilla/RefPtr.h"
+#include "nsISupports.h"
+#include "nsMenuGroupOwnerX.h"
+#include "nsMenuItemIconX.h"
+#include "nsChangeObserver.h"
+#include "nsStringFwd.h"
+
+#import <Cocoa/Cocoa.h>
+
+class nsMenuItemIconX;
+class nsMenuX;
+class nsMenuParentX;
+
+namespace mozilla {
+namespace dom {
+class Element;
+}
+}  // namespace mozilla
+
+enum {
+  knsMenuItemNoModifier = 0,
+  knsMenuItemShiftModifier = (1 << 0),
+  knsMenuItemAltModifier = (1 << 1),
+  knsMenuItemControlModifier = (1 << 2),
+  knsMenuItemCommandModifier = (1 << 3)
+};
+
+enum EMenuItemType {
+  eRegularMenuItemType = 0,
+  eCheckboxMenuItemType,
+  eRadioMenuItemType,
+  eSeparatorMenuItemType
+};
+
+// Once instantiated, this object lives until its DOM node or its parent window
+// is destroyed. Do not hold references to this, they can become invalid any
+// time the DOM node can be destroyed.
+class nsMenuItemX final : public nsChangeObserver,
+                          public nsMenuItemIconX::Listener {
+ public:
+  nsMenuItemX(nsMenuX* aParent, const nsString& aLabel, EMenuItemType aItemType,
+              nsMenuGroupOwnerX* aMenuGroupOwner, nsIContent* aNode);
+
+  bool IsVisible() const { return mIsVisible; }
+
+  // Unregisters nsMenuX from the nsMenuGroupOwner, and nulls out the group
+  // owner pointer. This is needed because nsMenuX is reference-counted and can
+  // outlive its owner, and the menu group owner asserts that everything has
+  // been unregistered when it is destroyed.
+  void DetachFromGroupOwner();
+
+  // Nulls out our reference to the parent.
+  // This is needed because nsMenuX is reference-counted and can outlive its
+  // parent.
+  void DetachFromParent() { mMenuParent = nullptr; }
+
+  NS_INLINE_DECL_REFCOUNTING(nsMenuItemX)
+
+  NS_DECL_CHANGEOBSERVER
+
+  // nsMenuItemIconX::Listener
+  void IconUpdated() override;
+
+  // nsMenuItemX
+  nsresult SetChecked(bool aIsChecked);
+  EMenuItemType GetMenuItemType();
+  void DoCommand(NSEventModifierFlags aModifierFlags, int16_t aButton);
+  nsresult DispatchDOMEvent(const nsString& eventName,
+                            bool* preventDefaultCalled);
+  void SetupIcon();
+  nsMenuX* ParentMenu() { return mMenuParent; }
+  nsIContent* Content() { return mContent; }
+  NSMenuItem* NativeNSMenuItem() { return mNativeMenuItem; }
+
+  void Dump(uint32_t aIndent) const;
+
+ protected:
+  virtual ~nsMenuItemX();
+
+  void UncheckRadioSiblings(nsIContent* aCheckedElement);
+  void SetKeyEquiv();
+
+  nsCOMPtr<nsIContent> mContent;  // XUL <menuitem> or <menuseparator>
+
+  EMenuItemType mType;
+
+  // nsMenuItemX objects should always have a valid native menu item.
+  NSMenuItem* mNativeMenuItem = nil;             // [strong]
+  nsMenuX* mMenuParent = nullptr;                // [weak]
+  nsMenuGroupOwnerX* mMenuGroupOwner = nullptr;  // [weak]
+  RefPtr<mozilla::dom::Element> mCommandElement;
+  mozilla::UniquePtr<nsMenuItemIconX> mIcon;  // always non-null
+  bool mIsChecked = false;
+  bool mIsVisible = false;
+};
+
+#endif  // nsMenuItemX_h_
diff --git a/widget/cocoa/nsMenuItemX.mm b/widget/cocoa/nsMenuItemX.mm
new file mode 100644
index 0000000000..26241217dc
--- /dev/null
+++ b/widget/cocoa/nsMenuItemX.mm
@@ -0,0 +1,449 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsMenuItemX.h"
+#include "nsMenuBarX.h"
+#include "nsMenuX.h"
+#include "nsMenuItemIconX.h"
+#include "nsMenuUtilsX.h"
+#include "nsCocoaUtils.h"
+
+#include "nsObjCExceptions.h"
+
+#include "nsCOMPtr.h"
+#include "nsGkAtoms.h"
+
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/Event.h"
+#include "mozilla/ErrorResult.h"
+#include "nsIWidget.h"
+#include "mozilla/dom/Document.h"
+
+using namespace mozilla;
+
+using mozilla::dom::CallerType;
+using mozilla::dom::Event;
+
+nsMenuItemX::nsMenuItemX(nsMenuX* aParent, const nsString& aLabel,
+                         EMenuItemType aItemType,
+                         nsMenuGroupOwnerX* aMenuGroupOwner, nsIContent* aNode)
+    : mContent(aNode),
+      mType(aItemType),
+      mMenuParent(aParent),
+      mMenuGroupOwner(aMenuGroupOwner) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  MOZ_COUNT_CTOR(nsMenuItemX);
+
+  MOZ_RELEASE_ASSERT(mContent->IsElement(),
+                     "nsMenuItemX should only be created for elements");
+  NS_ASSERTION(mMenuGroupOwner, "No menu owner given, must have one!");
+
+  mMenuGroupOwner->RegisterForContentChanges(mContent, this);
+
+  dom::Document* doc = mContent->GetUncomposedDoc();
+
+  // if we have a command associated with this menu item, register for changes
+  // to the command DOM node
+  if (doc) {
+    nsAutoString ourCommand;
+    mContent->AsElement()->GetAttr(nsGkAtoms::command, ourCommand);
+
+    if (!ourCommand.IsEmpty()) {
+      dom::Element* commandElement = doc->GetElementById(ourCommand);
+
+      if (commandElement) {
+        mCommandElement = commandElement;
+        // register to observe the command DOM element
+        mMenuGroupOwner->RegisterForContentChanges(mCommandElement, this);
+      }
+    }
+  }
+
+  // decide enabled state based on command content if it exists, otherwise do it
+  // based on our own content
+  bool isEnabled;
+  if (mCommandElement) {
+    isEnabled = !mCommandElement->AttrValueIs(
+        kNameSpaceID_None, nsGkAtoms::disabled, nsGkAtoms::_true, eCaseMatters);
+  } else {
+    isEnabled = !mContent->AsElement()->AttrValueIs(
+        kNameSpaceID_None, nsGkAtoms::disabled, nsGkAtoms::_true, eCaseMatters);
+  }
+
+  // set up the native menu item
+  if (mType == eSeparatorMenuItemType) {
+    mNativeMenuItem = [[NSMenuItem separatorItem] retain];
+  } else {
+    NSString* newCocoaLabelString =
+        nsMenuUtilsX::GetTruncatedCocoaLabel(aLabel);
+    mNativeMenuItem = [[NSMenuItem alloc] initWithTitle:newCocoaLabelString
+                                                 action:nil
+                                          keyEquivalent:@""];
+
+    mIsChecked = mContent->AsElement()->AttrValueIs(
+        kNameSpaceID_None, nsGkAtoms::checked, nsGkAtoms::_true, eCaseMatters);
+
+    mNativeMenuItem.enabled = isEnabled;
+    mNativeMenuItem.state =
+        mIsChecked ? NSControlStateValueOn : NSControlStateValueOff;
+
+    SetKeyEquiv();
+  }
+
+  mIcon = MakeUnique<nsMenuItemIconX>(this);
+
+  mIsVisible = !nsMenuUtilsX::NodeIsHiddenOrCollapsed(mContent);
+
+  // All menu items other than the "Copy" menu item share the same target and
+  // action, and are differentiated be a unique (representedObject, tag) pair.
+  // The "Copy" menu item is a special case that requires a macOS-default
+  // action of `copy:` and a default target in order for the "Edit" menu to be
+  // populated with OS-provided menu items such as the Emoji picker,
+  // especially in multi-language environments (see bug 1478347). Our
+  // application delegate implements `copy:` by simply forwarding it to
+  // [nsMenuBarX::sNativeEventTarget menuItemHit:].
+  if (mContent->AsElement()->AttrValueIs(kNameSpaceID_None, nsGkAtoms::id,
+                                         u"menu_copy"_ns, eCaseMatters)) {
+    mNativeMenuItem.action = @selector(copy:);
+  } else {
+    mNativeMenuItem.action = @selector(menuItemHit:);
+    mNativeMenuItem.target = nsMenuBarX::sNativeEventTarget;
+  }
+
+  mNativeMenuItem.representedObject = mMenuGroupOwner->GetRepresentedObject();
+  mNativeMenuItem.tag = mMenuGroupOwner->RegisterForCommand(this);
+
+  if (mIsVisible) {
+    SetupIcon();
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+nsMenuItemX::~nsMenuItemX() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // autorelease the native menu item so that anything else happening to this
+  // object happens before the native menu item actually dies
+  [mNativeMenuItem autorelease];
+
+  DetachFromGroupOwner();
+
+  MOZ_COUNT_DTOR(nsMenuItemX);
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuItemX::DetachFromGroupOwner() {
+  if (mMenuGroupOwner) {
+    mMenuGroupOwner->UnregisterCommand(mNativeMenuItem.tag);
+
+    if (mContent) {
+      mMenuGroupOwner->UnregisterForContentChanges(mContent);
+    }
+    if (mCommandElement) {
+      mMenuGroupOwner->UnregisterForContentChanges(mCommandElement);
+    }
+  }
+
+  mMenuGroupOwner = nullptr;
+}
+
+nsresult nsMenuItemX::SetChecked(bool aIsChecked) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  mIsChecked = aIsChecked;
+
+  // update the content model. This will also handle unchecking our siblings
+  // if we are a radiomenu
+  if (mIsChecked) {
+    mContent->AsElement()->SetAttr(kNameSpaceID_None, nsGkAtoms::checked,
+                                   u"true"_ns, true);
+  } else {
+    mContent->AsElement()->UnsetAttr(kNameSpaceID_None, nsGkAtoms::checked,
+                                     true);
+  }
+
+  // update native menu item
+  mNativeMenuItem.state =
+      mIsChecked ? NSControlStateValueOn : NSControlStateValueOff;
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+EMenuItemType nsMenuItemX::GetMenuItemType() { return mType; }
+
+// Executes the "cached" javaScript command.
+// Returns NS_OK if the command was executed properly, otherwise an error code.
+void nsMenuItemX::DoCommand(NSEventModifierFlags aModifierFlags,
+                            int16_t aButton) {
+  // flip "checked" state if we're a checkbox menu, or an un-checked radio menu
+  if (mType == eCheckboxMenuItemType ||
+      (mType == eRadioMenuItemType && !mIsChecked)) {
+    if (!mContent->AsElement()->AttrValueIs(kNameSpaceID_None,
+                                            nsGkAtoms::autocheck,
+                                            nsGkAtoms::_false, eCaseMatters)) {
+      SetChecked(!mIsChecked);
+    }
+    /* the AttributeChanged code will update all the internal state */
+  }
+
+  nsMenuUtilsX::DispatchCommandTo(mContent, aModifierFlags, aButton);
+}
+
+nsresult nsMenuItemX::DispatchDOMEvent(const nsString& eventName,
+                                       bool* preventDefaultCalled) {
+  if (!mContent) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // get owner document for content
+  nsCOMPtr<dom::Document> parentDoc = mContent->OwnerDoc();
+
+  // create DOM event
+  ErrorResult rv;
+  RefPtr<Event> event =
+      parentDoc->CreateEvent(u"Events"_ns, CallerType::System, rv);
+  if (rv.Failed()) {
+    NS_WARNING("Failed to create Event");
+    return rv.StealNSResult();
+  }
+  event->InitEvent(eventName, true, true);
+
+  // mark DOM event as trusted
+  event->SetTrusted(true);
+
+  // send DOM event
+  *preventDefaultCalled =
+      mContent->DispatchEvent(*event, CallerType::System, rv);
+  if (rv.Failed()) {
+    NS_WARNING("Failed to send DOM event via EventTarget");
+    return rv.StealNSResult();
+  }
+
+  return NS_OK;
+}
+
+// Walk the sibling list looking for nodes with the same name and
+// uncheck them all.
+void nsMenuItemX::UncheckRadioSiblings(nsIContent* aCheckedContent) {
+  nsAutoString myGroupName;
+  aCheckedContent->AsElement()->GetAttr(nsGkAtoms::name, myGroupName);
+  if (!myGroupName.Length()) {  // no groupname, nothing to do
+    return;
+  }
+
+  nsCOMPtr<nsIContent> parent = aCheckedContent->GetParent();
+  if (!parent) {
+    return;
+  }
+
+  // loop over siblings
+  for (nsIContent* sibling = parent->GetFirstChild(); sibling;
+       sibling = sibling->GetNextSibling()) {
+    if (sibling != aCheckedContent && sibling->IsElement()) {  // skip this node
+      // if the current sibling is in the same group, clear it
+      if (sibling->AsElement()->AttrValueIs(kNameSpaceID_None, nsGkAtoms::name,
+                                            myGroupName, eCaseMatters)) {
+        sibling->AsElement()->SetAttr(kNameSpaceID_None, nsGkAtoms::checked,
+                                      u"false"_ns, true);
+      }
+    }
+  }
+}
+
+void nsMenuItemX::SetKeyEquiv() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // Set key shortcut and modifiers
+  nsAutoString keyValue;
+  mContent->AsElement()->GetAttr(nsGkAtoms::key, keyValue);
+
+  if (!keyValue.IsEmpty() && mContent->GetUncomposedDoc()) {
+    dom::Element* keyContent =
+        mContent->GetUncomposedDoc()->GetElementById(keyValue);
+    if (keyContent) {
+      nsAutoString keyChar;
+      bool hasKey = keyContent->GetAttr(nsGkAtoms::key, keyChar);
+
+      if (!hasKey || keyChar.IsEmpty()) {
+        nsAutoString keyCodeName;
+        keyContent->GetAttr(nsGkAtoms::keycode, keyCodeName);
+        uint32_t charCode =
+            nsCocoaUtils::ConvertGeckoNameToMacCharCode(keyCodeName);
+        if (charCode) {
+          keyChar.Assign(charCode);
+        } else {
+          keyChar.AssignLiteral(u" ");
+        }
+      }
+
+      nsAutoString modifiersStr;
+      keyContent->GetAttr(nsGkAtoms::modifiers, modifiersStr);
+      uint8_t modifiers =
+          nsMenuUtilsX::GeckoModifiersForNodeAttribute(modifiersStr);
+
+      unsigned int macModifiers =
+          nsMenuUtilsX::MacModifiersForGeckoModifiers(modifiers);
+      mNativeMenuItem.keyEquivalentModifierMask = macModifiers;
+
+      NSString* keyEquivalent =
+          [[NSString stringWithCharacters:(unichar*)keyChar.get()
+                                   length:keyChar.Length()] lowercaseString];
+      if ([keyEquivalent isEqualToString:@" "]) {
+        mNativeMenuItem.keyEquivalent = @"";
+      } else {
+        mNativeMenuItem.keyEquivalent = keyEquivalent;
+      }
+
+      return;
+    }
+  }
+
+  // if the key was removed, clear the key
+  mNativeMenuItem.keyEquivalent = @"";
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuItemX::Dump(uint32_t aIndent) const {
+  printf("%*s - item [%p] %-16s <%s>\n", aIndent * 2, "", this,
+         mType == eSeparatorMenuItemType ? "----"
+                                         : [mNativeMenuItem.title UTF8String],
+         NS_ConvertUTF16toUTF8(mContent->NodeName()).get());
+}
+
+//
+// nsChangeObserver
+//
+
+void nsMenuItemX::ObserveAttributeChanged(dom::Document* aDocument,
+                                          nsIContent* aContent,
+                                          nsAtom* aAttribute) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  if (!aContent) {
+    return;
+  }
+
+  if (aContent == mContent) {  // our own content node changed
+    if (aAttribute == nsGkAtoms::checked) {
+      // if we're a radio menu, uncheck our sibling radio items. No need to
+      // do any of this if we're just a normal check menu.
+      if (mType == eRadioMenuItemType &&
+          mContent->AsElement()->AttrValueIs(kNameSpaceID_None,
+                                             nsGkAtoms::checked,
+                                             nsGkAtoms::_true, eCaseMatters)) {
+        UncheckRadioSiblings(mContent);
+      }
+      mMenuParent->SetRebuild(true);
+    } else if (aAttribute == nsGkAtoms::hidden ||
+               aAttribute == nsGkAtoms::collapsed) {
+      bool isVisible = !nsMenuUtilsX::NodeIsHiddenOrCollapsed(mContent);
+      if (isVisible != mIsVisible) {
+        mIsVisible = isVisible;
+        RefPtr<nsMenuItemX> self = this;
+        mMenuParent->MenuChildChangedVisibility(nsMenuParentX::MenuChild(self),
+                                                isVisible);
+        if (mIsVisible) {
+          SetupIcon();
+        }
+      }
+      mMenuParent->SetRebuild(true);
+    } else if (aAttribute == nsGkAtoms::label) {
+      if (mType != eSeparatorMenuItemType) {
+        nsAutoString newLabel;
+        mContent->AsElement()->GetAttr(nsGkAtoms::label, newLabel);
+        mNativeMenuItem.title = nsMenuUtilsX::GetTruncatedCocoaLabel(newLabel);
+      }
+    } else if (aAttribute == nsGkAtoms::key) {
+      SetKeyEquiv();
+    } else if (aAttribute == nsGkAtoms::image) {
+      SetupIcon();
+    } else if (aAttribute == nsGkAtoms::disabled) {
+      mNativeMenuItem.enabled = !aContent->AsElement()->AttrValueIs(
+          kNameSpaceID_None, nsGkAtoms::disabled, nsGkAtoms::_true,
+          eCaseMatters);
+    }
+  } else if (aContent == mCommandElement) {
+    // the only thing that really matters when the menu isn't showing is the
+    // enabled state since it enables/disables keyboard commands
+    if (aAttribute == nsGkAtoms::disabled) {
+      // first we sync our menu item DOM node with the command DOM node
+      nsAutoString commandDisabled;
+      nsAutoString menuDisabled;
+      aContent->AsElement()->GetAttr(nsGkAtoms::disabled, commandDisabled);
+      mContent->AsElement()->GetAttr(nsGkAtoms::disabled, menuDisabled);
+      if (!commandDisabled.Equals(menuDisabled)) {
+        // The menu's disabled state needs to be updated to match the command.
+        if (commandDisabled.IsEmpty()) {
+          mContent->AsElement()->UnsetAttr(kNameSpaceID_None,
+                                           nsGkAtoms::disabled, true);
+        } else {
+          mContent->AsElement()->SetAttr(kNameSpaceID_None, nsGkAtoms::disabled,
+                                         commandDisabled, true);
+        }
+      }
+      // now we sync our native menu item with the command DOM node
+      mNativeMenuItem.enabled = !aContent->AsElement()->AttrValueIs(
+          kNameSpaceID_None, nsGkAtoms::disabled, nsGkAtoms::_true,
+          eCaseMatters);
+    }
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+bool IsMenuStructureElement(nsIContent* aContent) {
+  return aContent->IsAnyOfXULElements(nsGkAtoms::menu, nsGkAtoms::menuitem,
+                                      nsGkAtoms::menuseparator);
+}
+
+void nsMenuItemX::ObserveContentRemoved(dom::Document* aDocument,
+                                        nsIContent* aContainer,
+                                        nsIContent* aChild,
+                                        nsIContent* aPreviousSibling) {
+  MOZ_RELEASE_ASSERT(mMenuGroupOwner);
+  MOZ_RELEASE_ASSERT(mMenuParent);
+
+  if (aChild == mCommandElement) {
+    mMenuGroupOwner->UnregisterForContentChanges(mCommandElement);
+    mCommandElement = nullptr;
+  }
+  if (IsMenuStructureElement(aChild)) {
+    mMenuParent->SetRebuild(true);
+  }
+}
+
+void nsMenuItemX::ObserveContentInserted(dom::Document* aDocument,
+                                         nsIContent* aContainer,
+                                         nsIContent* aChild) {
+  MOZ_RELEASE_ASSERT(mMenuParent);
+
+  // The child node could come from the custom element that is for display, so
+  // only rebuild the menu if the child is related to the structure of the
+  // menu.
+  if (IsMenuStructureElement(aChild)) {
+    mMenuParent->SetRebuild(true);
+  }
+}
+
+void nsMenuItemX::SetupIcon() {
+  if (mType != eRegularMenuItemType) {
+    // Don't support icons on checkbox and radio menuitems, for consistency with
+    // Windows & Linux.
+    return;
+  }
+
+  mIcon->SetupIcon(mContent);
+  mNativeMenuItem.image = mIcon->GetIconImage();
+}
+
+void nsMenuItemX::IconUpdated() {
+  mNativeMenuItem.image = mIcon->GetIconImage();
+}
diff --git a/widget/cocoa/nsMenuParentX.h b/widget/cocoa/nsMenuParentX.h
new file mode 100644
index 0000000000..a1f705631a
--- /dev/null
+++ b/widget/cocoa/nsMenuParentX.h
@@ -0,0 +1,31 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsMenuParentX_h_
+#define nsMenuParentX_h_
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/Variant.h"
+
+class nsMenuX;
+class nsMenuBarX;
+class nsMenuItemX;
+
+// A base class for objects that can be the parent of an nsMenuX or nsMenuItemX.
+class nsMenuParentX {
+ public:
+  using MenuChild = mozilla::Variant<RefPtr<nsMenuX>, RefPtr<nsMenuItemX>>;
+
+  // XXXmstange double-check that this is still needed
+  virtual nsMenuBarX* AsMenuBar() { return nullptr; }
+
+  // Called when aChild becomes visible or hidden, so that the parent can insert
+  // or remove the child's native menu item from its NSMenu and update its state
+  // of visible items.
+  virtual void MenuChildChangedVisibility(const MenuChild& aChild,
+                                          bool aIsVisible) = 0;
+};
+
+#endif  // nsMenuParentX_h_
diff --git a/widget/cocoa/nsMenuUtilsX.h b/widget/cocoa/nsMenuUtilsX.h
new file mode 100644
index 0000000000..5b8993713b
--- /dev/null
+++ b/widget/cocoa/nsMenuUtilsX.h
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsMenuUtilsX_h_
+#define nsMenuUtilsX_h_
+
+#include "nscore.h"
+#include "nsStringFwd.h"
+
+#import <Cocoa/Cocoa.h>
+
+class nsIContent;
+class nsMenuBarX;
+class nsMenuX;
+
+// Namespace containing utility functions used in our native menu
+// implementation.
+namespace nsMenuUtilsX {
+void DispatchCommandTo(nsIContent* aTargetContent,
+                       NSEventModifierFlags aModifierFlags, int16_t aButton);
+NSString* GetTruncatedCocoaLabel(const nsString& itemLabel);
+uint8_t GeckoModifiersForNodeAttribute(const nsString& modifiersAttribute);
+unsigned int MacModifiersForGeckoModifiers(uint8_t geckoModifiers);
+nsMenuBarX* GetHiddenWindowMenuBar();   // returned object is not retained
+NSMenuItem* GetStandardEditMenuItem();  // returned object is not retained
+bool NodeIsHiddenOrCollapsed(nsIContent* aContent);
+
+// Find the menu item by following the path aLocationString from aRootMenu.
+// aLocationString is a '|'-separated list of integers, where each integer is
+// the index of the menu item in the menu.
+// aIsMenuBar needs to be true if aRootMenu is the app's mainMenu, so that the
+// app menu can be skipped during the search.
+NSMenuItem* NativeMenuItemWithLocation(NSMenu* aRootMenu,
+                                       NSString* aLocationString,
+                                       bool aIsMenuBar);
+
+// Traverse the menu tree and check that there are no cycles or NSMenu(Item)
+// objects that are used more than once. If inconsistencies are found, these
+// functions crash the process.
+void CheckNativeMenuConsistency(NSMenu* aMenu);
+void CheckNativeMenuConsistency(NSMenuItem* aMenuItem);
+
+// Print out debugging information about the native menu tree structure.
+void DumpNativeMenu(NSMenu* aMenu);
+void DumpNativeMenuItem(NSMenuItem* aMenuItem);
+
+extern bool gIsSynchronouslyActivatingNativeMenuItemDuringTest;
+
+}  // namespace nsMenuUtilsX
+
+#endif  // nsMenuUtilsX_h_
diff --git a/widget/cocoa/nsMenuUtilsX.mm b/widget/cocoa/nsMenuUtilsX.mm
new file mode 100644
index 0000000000..9a950221cd
--- /dev/null
+++ b/widget/cocoa/nsMenuUtilsX.mm
@@ -0,0 +1,316 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsMenuUtilsX.h"
+#include <unordered_set>
+
+#include "mozilla/EventForwards.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/DocumentInlines.h"
+#include "mozilla/dom/Event.h"
+#include "mozilla/dom/XULCommandEvent.h"
+#include "nsMenuBarX.h"
+#include "nsMenuX.h"
+#include "nsMenuItemX.h"
+#include "NativeMenuMac.h"
+#include "nsObjCExceptions.h"
+#include "nsCocoaUtils.h"
+#include "nsCocoaWindow.h"
+#include "nsGkAtoms.h"
+#include "nsGlobalWindowInner.h"
+#include "nsPIDOMWindow.h"
+#include "nsQueryObject.h"
+
+using namespace mozilla;
+
+bool nsMenuUtilsX::gIsSynchronouslyActivatingNativeMenuItemDuringTest = false;
+
+void nsMenuUtilsX::DispatchCommandTo(nsIContent* aTargetContent,
+                                     NSEventModifierFlags aModifierFlags,
+                                     int16_t aButton) {
+  MOZ_ASSERT(aTargetContent, "null ptr");
+
+  dom::Document* doc = aTargetContent->OwnerDoc();
+  if (doc) {
+    RefPtr<dom::XULCommandEvent> event =
+        new dom::XULCommandEvent(doc, doc->GetPresContext(), nullptr);
+
+    bool ctrlKey = aModifierFlags & NSEventModifierFlagControl;
+    bool altKey = aModifierFlags & NSEventModifierFlagOption;
+    bool shiftKey = aModifierFlags & NSEventModifierFlagShift;
+    bool cmdKey = aModifierFlags & NSEventModifierFlagCommand;
+
+    IgnoredErrorResult rv;
+    event->InitCommandEvent(u"command"_ns, true, true,
+                            nsGlobalWindowInner::Cast(doc->GetInnerWindow()), 0,
+                            ctrlKey, altKey, shiftKey, cmdKey, aButton, nullptr,
+                            0, rv);
+    if (!rv.Failed()) {
+      event->SetTrusted(true);
+      aTargetContent->DispatchEvent(*event);
+    }
+  }
+}
+
+NSString* nsMenuUtilsX::GetTruncatedCocoaLabel(const nsString& itemLabel) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // We want to truncate long strings to some reasonable pixel length but there
+  // is no good API for doing that which works for all OS versions and
+  // architectures. For now we'll do nothing for consistency and depend on good
+  // user interface design to limit string lengths.
+  return [NSString
+      stringWithCharacters:reinterpret_cast<const unichar*>(itemLabel.get())
+                    length:itemLabel.Length()];
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+uint8_t nsMenuUtilsX::GeckoModifiersForNodeAttribute(
+    const nsString& modifiersAttribute) {
+  uint8_t modifiers = knsMenuItemNoModifier;
+  char* str = ToNewCString(modifiersAttribute);
+  char* newStr;
+  char* token = strtok_r(str, ", \t", &newStr);
+  while (token != nullptr) {
+    if (strcmp(token, "shift") == 0) {
+      modifiers |= knsMenuItemShiftModifier;
+    } else if (strcmp(token, "alt") == 0) {
+      modifiers |= knsMenuItemAltModifier;
+    } else if (strcmp(token, "control") == 0) {
+      modifiers |= knsMenuItemControlModifier;
+    } else if ((strcmp(token, "accel") == 0) || (strcmp(token, "meta") == 0)) {
+      modifiers |= knsMenuItemCommandModifier;
+    }
+    token = strtok_r(newStr, ", \t", &newStr);
+  }
+  free(str);
+
+  return modifiers;
+}
+
+unsigned int nsMenuUtilsX::MacModifiersForGeckoModifiers(
+    uint8_t geckoModifiers) {
+  unsigned int macModifiers = 0;
+
+  if (geckoModifiers & knsMenuItemShiftModifier) {
+    macModifiers |= NSEventModifierFlagShift;
+  }
+  if (geckoModifiers & knsMenuItemAltModifier) {
+    macModifiers |= NSEventModifierFlagOption;
+  }
+  if (geckoModifiers & knsMenuItemControlModifier) {
+    macModifiers |= NSEventModifierFlagControl;
+  }
+  if (geckoModifiers & knsMenuItemCommandModifier) {
+    macModifiers |= NSEventModifierFlagCommand;
+  }
+
+  return macModifiers;
+}
+
+nsMenuBarX* nsMenuUtilsX::GetHiddenWindowMenuBar() {
+  if (gfxPlatform::IsHeadless()) {
+    return nullptr;
+  }
+  nsIWidget* hiddenWindowWidgetNoCOMPtr = nsCocoaUtils::GetHiddenWindowWidget();
+  if (hiddenWindowWidgetNoCOMPtr) {
+    return static_cast<nsCocoaWindow*>(hiddenWindowWidgetNoCOMPtr)
+        ->GetMenuBar();
+  }
+  return nullptr;
+}
+
+// It would be nice if we could localize these edit menu names.
+NSMenuItem* nsMenuUtilsX::GetStandardEditMenuItem() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // In principle we should be able to allocate this once and then always
+  // return the same object.  But weird interactions happen between native
+  // app-modal dialogs and Gecko-modal dialogs that open above them.  So what
+  // we return here isn't always released before it needs to be added to
+  // another menu.  See bmo bug 468393.
+  NSMenuItem* standardEditMenuItem =
+      [[[NSMenuItem alloc] initWithTitle:@"Edit" action:nil
+                           keyEquivalent:@""] autorelease];
+  NSMenu* standardEditMenu = [[NSMenu alloc] initWithTitle:@"Edit"];
+  standardEditMenuItem.submenu = standardEditMenu;
+  [standardEditMenu release];
+
+  // Add Undo
+  NSMenuItem* undoItem = [[NSMenuItem alloc] initWithTitle:@"Undo"
+                                                    action:@selector(undo:)
+                                             keyEquivalent:@"z"];
+  [standardEditMenu addItem:undoItem];
+  [undoItem release];
+
+  // Add Redo
+  NSMenuItem* redoItem = [[NSMenuItem alloc] initWithTitle:@"Redo"
+                                                    action:@selector(redo:)
+                                             keyEquivalent:@"Z"];
+  [standardEditMenu addItem:redoItem];
+  [redoItem release];
+
+  // Add separator
+  [standardEditMenu addItem:[NSMenuItem separatorItem]];
+
+  // Add Cut
+  NSMenuItem* cutItem = [[NSMenuItem alloc] initWithTitle:@"Cut"
+                                                   action:@selector(cut:)
+                                            keyEquivalent:@"x"];
+  [standardEditMenu addItem:cutItem];
+  [cutItem release];
+
+  // Add Copy
+  NSMenuItem* copyItem = [[NSMenuItem alloc] initWithTitle:@"Copy"
+                                                    action:@selector(copy:)
+                                             keyEquivalent:@"c"];
+  [standardEditMenu addItem:copyItem];
+  [copyItem release];
+
+  // Add Paste
+  NSMenuItem* pasteItem = [[NSMenuItem alloc] initWithTitle:@"Paste"
+                                                     action:@selector(paste:)
+                                              keyEquivalent:@"v"];
+  [standardEditMenu addItem:pasteItem];
+  [pasteItem release];
+
+  // Add Delete
+  NSMenuItem* deleteItem = [[NSMenuItem alloc] initWithTitle:@"Delete"
+                                                      action:@selector(delete:)
+                                               keyEquivalent:@""];
+  [standardEditMenu addItem:deleteItem];
+  [deleteItem release];
+
+  // Add Select All
+  NSMenuItem* selectAllItem =
+      [[NSMenuItem alloc] initWithTitle:@"Select All"
+                                 action:@selector(selectAll:)
+                          keyEquivalent:@"a"];
+  [standardEditMenu addItem:selectAllItem];
+  [selectAllItem release];
+
+  return standardEditMenuItem;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+bool nsMenuUtilsX::NodeIsHiddenOrCollapsed(nsIContent* aContent) {
+  return aContent->IsElement() && (aContent->AsElement()->AttrValueIs(
+                                       kNameSpaceID_None, nsGkAtoms::hidden,
+                                       nsGkAtoms::_true, eCaseMatters) ||
+                                   aContent->AsElement()->AttrValueIs(
+                                       kNameSpaceID_None, nsGkAtoms::collapsed,
+                                       nsGkAtoms::_true, eCaseMatters));
+}
+
+NSMenuItem* nsMenuUtilsX::NativeMenuItemWithLocation(NSMenu* aRootMenu,
+                                                     NSString* aLocationString,
+                                                     bool aIsMenuBar) {
+  NSArray<NSString*>* indexes =
+      [aLocationString componentsSeparatedByString:@"|"];
+  unsigned int pathLength = indexes.count;
+  if (pathLength == 0) {
+    return nil;
+  }
+
+  NSMenu* currentSubmenu = aRootMenu;
+  for (unsigned int depth = 0; depth < pathLength; depth++) {
+    NSInteger targetIndex = [indexes objectAtIndex:depth].integerValue;
+    if (aIsMenuBar && depth == 0) {
+      // We remove the application menu from consideration for the top-level
+      // menu.
+      targetIndex++;
+    }
+    int itemCount = currentSubmenu.numberOfItems;
+    if (targetIndex >= itemCount) {
+      return nil;
+    }
+    NSMenuItem* menuItem = [currentSubmenu itemAtIndex:targetIndex];
+    // if this is the last index just return the menu item
+    if (depth == pathLength - 1) {
+      return menuItem;
+    }
+    // if this is not the last index find the submenu and keep going
+    if (menuItem.hasSubmenu) {
+      currentSubmenu = menuItem.submenu;
+    } else {
+      return nil;
+    }
+  }
+
+  return nil;
+}
+
+static void CheckNativeMenuConsistencyImpl(
+    NSMenu* aMenu, std::unordered_set<void*>& aSeenObjects);
+
+static void CheckNativeMenuItemConsistencyImpl(
+    NSMenuItem* aMenuItem, std::unordered_set<void*>& aSeenObjects) {
+  bool inserted = aSeenObjects.insert(aMenuItem).second;
+  MOZ_RELEASE_ASSERT(inserted,
+                     "Duplicate NSMenuItem object in native menu structure");
+  if (aMenuItem.hasSubmenu) {
+    CheckNativeMenuConsistencyImpl(aMenuItem.submenu, aSeenObjects);
+  }
+}
+
+static void CheckNativeMenuConsistencyImpl(
+    NSMenu* aMenu, std::unordered_set<void*>& aSeenObjects) {
+  bool inserted = aSeenObjects.insert(aMenu).second;
+  MOZ_RELEASE_ASSERT(inserted,
+                     "Duplicate NSMenu object in native menu structure");
+  for (NSMenuItem* item in aMenu.itemArray) {
+    CheckNativeMenuItemConsistencyImpl(item, aSeenObjects);
+  }
+}
+
+void nsMenuUtilsX::CheckNativeMenuConsistency(NSMenu* aMenu) {
+  std::unordered_set<void*> seenObjects;
+  CheckNativeMenuConsistencyImpl(aMenu, seenObjects);
+}
+
+void nsMenuUtilsX::CheckNativeMenuConsistency(NSMenuItem* aMenuItem) {
+  std::unordered_set<void*> seenObjects;
+  CheckNativeMenuItemConsistencyImpl(aMenuItem, seenObjects);
+}
+
+static void DumpNativeNSMenuItemImpl(NSMenuItem* aItem, uint32_t aIndent,
+                                     const Maybe<int>& aIndexInParentMenu);
+
+static void DumpNativeNSMenuImpl(NSMenu* aMenu, uint32_t aIndent) {
+  printf("%*sNSMenu [%p] %-16s\n", aIndent * 2, "", aMenu,
+         (aMenu.title.length == 0 ? "(no title)" : aMenu.title.UTF8String));
+  int index = 0;
+  for (NSMenuItem* item in aMenu.itemArray) {
+    DumpNativeNSMenuItemImpl(item, aIndent + 1, Some(index));
+    index++;
+  }
+}
+
+static void DumpNativeNSMenuItemImpl(NSMenuItem* aItem, uint32_t aIndent,
+                                     const Maybe<int>& aIndexInParentMenu) {
+  printf("%*s", aIndent * 2, "");
+  if (aIndexInParentMenu) {
+    printf("[%d] ", *aIndexInParentMenu);
+  }
+  printf(
+      "NSMenuItem [%p] %-16s%s\n", aItem,
+      aItem.isSeparatorItem
+          ? "----"
+          : (aItem.title.length == 0 ? "(no title)" : aItem.title.UTF8String),
+      aItem.hasSubmenu ? " [hasSubmenu]" : "");
+  if (aItem.hasSubmenu) {
+    DumpNativeNSMenuImpl(aItem.submenu, aIndent + 1);
+  }
+}
+
+void nsMenuUtilsX::DumpNativeMenu(NSMenu* aMenu) {
+  DumpNativeNSMenuImpl(aMenu, 0);
+}
+
+void nsMenuUtilsX::DumpNativeMenuItem(NSMenuItem* aMenuItem) {
+  DumpNativeNSMenuItemImpl(aMenuItem, 0, Nothing());
+}
diff --git a/widget/cocoa/nsMenuX.h b/widget/cocoa/nsMenuX.h
new file mode 100644
index 0000000000..cdc5884a99
--- /dev/null
+++ b/widget/cocoa/nsMenuX.h
@@ -0,0 +1,313 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsMenuX_h_
+#define nsMenuX_h_
+
+#import <Cocoa/Cocoa.h>
+
+#include "mozilla/EventForwards.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Variant.h"
+#include "nsISupports.h"
+#include "nsMenuParentX.h"
+#include "nsMenuBarX.h"
+#include "nsMenuGroupOwnerX.h"
+#include "nsMenuItemIconX.h"
+#include "nsCOMPtr.h"
+#include "nsChangeObserver.h"
+#include "nsThreadUtils.h"
+
+class nsMenuX;
+class nsMenuItemX;
+class nsIWidget;
+
+// MenuDelegate is used to receive Cocoa notifications for setting
+// up carbon events. Protocol is defined as of 10.6 SDK.
+@interface MenuDelegate : NSObject <NSMenuDelegate> {
+  nsMenuX* mGeckoMenu;  // weak ref
+  NSMutableArray* mBlocksToRunWhenOpen;
+}
+- (id)initWithGeckoMenu:(nsMenuX*)geckoMenu;
+- (void)runBlockWhenOpen:(void (^)())block;
+- (void)menu:(NSMenu*)menu willActivateItem:(NSMenuItem*)item;
+@end
+
+class nsMenuXObserver {
+ public:
+  // Called when a menu in this menu subtree opens, before popupshowing.
+  // No strong reference is held to the observer during the call.
+  virtual void OnMenuWillOpen(mozilla::dom::Element* aPopupElement) = 0;
+
+  // Called when a menu in this menu subtree opened, after popupshown.
+  // No strong reference is held to the observer during the call.
+  virtual void OnMenuDidOpen(mozilla::dom::Element* aPopupElement) = 0;
+
+  // Called before a menu item is activated.
+  virtual void OnMenuWillActivateItem(
+      mozilla::dom::Element* aPopupElement,
+      mozilla::dom::Element* aMenuItemElement) = 0;
+
+  // Called when a menu in this menu subtree closed, after popuphidden.
+  // No strong reference is held to the observer during the call.
+  virtual void OnMenuClosed(mozilla::dom::Element* aPopupElement) = 0;
+};
+
+// Once instantiated, this object lives until its DOM node or its parent window
+// is destroyed. Do not hold references to this, they can become invalid any
+// time the DOM node can be destroyed.
+class nsMenuX final : public nsMenuParentX,
+                      public nsChangeObserver,
+                      public nsMenuItemIconX::Listener,
+                      public nsMenuXObserver {
+ public:
+  using Observer = nsMenuXObserver;
+
+  // aParent is optional.
+  nsMenuX(nsMenuParentX* aParent, nsMenuGroupOwnerX* aMenuGroupOwner,
+          nsIContent* aContent);
+
+  NS_INLINE_DECL_REFCOUNTING(nsMenuX)
+
+  // If > 0, the OS is indexing all the app's menus (triggered by opening
+  // Help menu on Leopard and higher).  There are some things that are
+  // unsafe to do while this is happening.
+  static int32_t sIndexingMenuLevel;
+
+  NS_DECL_CHANGEOBSERVER
+
+  // nsMenuItemIconX::Listener
+  void IconUpdated() override;
+
+  // nsMenuXObserver, to forward notifications from our children to our
+  // observer.
+  void OnMenuWillOpen(mozilla::dom::Element* aPopupElement) override;
+  void OnMenuDidOpen(mozilla::dom::Element* aPopupElement) override;
+  void OnMenuWillActivateItem(mozilla::dom::Element* aPopupElement,
+                              mozilla::dom::Element* aMenuItemElement) override;
+  void OnMenuClosed(mozilla::dom::Element* aPopupElement) override;
+
+  bool IsVisible() const { return mVisible; }
+
+  // Unregisters nsMenuX from the nsMenuGroupOwner, and nulls out the group
+  // owner pointer, on this nsMenuX and also all nested nsMenuX and nsMenuItemX
+  // objects. This is needed because nsMenuX is reference-counted and can
+  // outlive its owner, and the menu group owner asserts that everything has
+  // been unregistered when it is destroyed.
+  void DetachFromGroupOwnerRecursive();
+
+  // Nulls out our reference to the parent.
+  // This is needed because nsMenuX is reference-counted and can outlive its
+  // parent.
+  void DetachFromParent() { mParent = nullptr; }
+
+  mozilla::Maybe<MenuChild> GetItemAt(uint32_t aPos);
+  uint32_t GetItemCount();
+
+  mozilla::Maybe<MenuChild> GetVisibleItemAt(uint32_t aPos);
+  nsresult GetVisibleItemCount(uint32_t& aCount);
+
+  mozilla::Maybe<MenuChild> GetItemForElement(
+      mozilla::dom::Element* aMenuChildElement);
+
+  // Asynchronously runs the command event on aItem, after the root menu has
+  // closed.
+  void ActivateItemAfterClosing(RefPtr<nsMenuItemX>&& aItem,
+                                NSEventModifierFlags aModifiers,
+                                int16_t aButton);
+
+  bool IsOpenForGecko() const { return mIsOpenForGecko; }
+
+  // Fires the popupshowing event and returns whether the handler allows the
+  // popup to open. When calling this method, the caller must hold a strong
+  // reference to this object, because other references to this object can be
+  // dropped during the handling of the DOM event.
+  MOZ_CAN_RUN_SCRIPT bool OnOpen();
+
+  void PopupShowingEventWasSentAndApprovedExternally() {
+    DidFirePopupShowing();
+  }
+
+  // Called from the menu delegate during menuWillOpen, or to simulate opening.
+  // Ignored if the menu is already considered open.
+  // When calling this method, the caller must hold a strong reference to this
+  // object, because other references to this object can be dropped during the
+  // handling of the DOM event.
+  // TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230)
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY void MenuOpened();
+
+  // Called from the menu delegate during menuDidClose, or to simulate closing.
+  // Ignored if the menu is already considered closed.
+  // When calling this method, the caller must hold a strong reference to this
+  // object, because other references to this object can be dropped during the
+  // handling of the DOM event.
+  void MenuClosed();
+
+  // Close the menu if it's open, and flush any pending popuphiding /
+  // popuphidden events.
+  bool Close();
+
+  // Called from the menu delegate during menu:willHighlightItem:.
+  // If called with Nothing(), it means that no item is highlighted.
+  // The index only accounts for visible items, i.e. items for which there
+  // exists an NSMenuItem* in mNativeMenu.
+  void OnHighlightedItemChanged(
+      const mozilla::Maybe<uint32_t>& aNewHighlightedIndex);
+
+  // Called from the menu delegate before an item anywhere in this menu is
+  // activated. Called after MenuClosed().
+  void OnWillActivateItem(NSMenuItem* aItem);
+
+  void SetRebuild(bool aMenuEvent);
+  void SetupIcon();
+  nsIContent* Content() { return mContent; }
+  NSMenuItem* NativeNSMenuItem() { return mNativeMenuItem; }
+  GeckoNSMenu* NativeNSMenu() { return mNativeMenu; }
+
+  void SetIconListener(nsMenuItemIconX::Listener* aListener) {
+    mIconListener = aListener;
+  }
+  void ClearIconListener() { mIconListener = nullptr; }
+
+  // nsMenuParentX
+  void MenuChildChangedVisibility(const MenuChild& aChild,
+                                  bool aIsVisible) override;
+
+  void Dump(uint32_t aIndent) const;
+
+  static bool IsXULHelpMenu(nsIContent* aMenuContent);
+  static bool IsXULWindowMenu(nsIContent* aMenuContent);
+
+  // Set an observer that gets notified of menu opening and closing.
+  // The menu does not keep a strong reference the observer. The observer must
+  // remove itself before it is destroyed.
+  void SetObserver(Observer* aObserver) { mObserver = aObserver; }
+
+  // Stop observing.
+  void ClearObserver() { mObserver = nullptr; }
+
+ protected:
+  virtual ~nsMenuX();
+
+  void RebuildMenu();
+  nsresult RemoveAll();
+  nsresult SetEnabled(bool aIsEnabled);
+  nsresult GetEnabled(bool* aIsEnabled);
+  already_AddRefed<nsIContent> GetMenuPopupContent();
+  void WillInsertChild(const MenuChild& aChild);
+  void WillRemoveChild(const MenuChild& aChild);
+  void AddMenuChild(MenuChild&& aChild);
+  void InsertMenuChild(MenuChild&& aChild);
+  void RemoveMenuChild(const MenuChild& aChild);
+  mozilla::Maybe<MenuChild> CreateMenuChild(nsIContent* aContent);
+  RefPtr<nsMenuItemX> CreateMenuItem(nsIContent* aMenuItemContent);
+  GeckoNSMenu* CreateMenuWithGeckoString(nsString& aMenuTitle,
+                                         bool aShowServices);
+  void DidFirePopupShowing();
+
+  // Find the index at which aChild needs to be inserted into mMenuChildren such
+  // that mMenuChildren remains in correct content order, i.e. the order in
+  // mMenuChildren is the same as the order of the DOM children of our
+  // <menupopup>.
+  size_t FindInsertionIndex(const MenuChild& aChild);
+
+  // Calculates the index at which aChild's NSMenuItem should be inserted into
+  // our NSMenu. The order of NSMenuItems in the NSMenu is the same as the order
+  // of menu children in mMenuChildren; the only difference is that
+  // mMenuChildren contains both visible and invisible children, and the NSMenu
+  // only contains visible items. So the insertion index is equal to the number
+  // of visible previous siblings of aChild in mMenuChildren.
+  NSInteger CalculateNativeInsertionPoint(const MenuChild& aChild);
+
+  // Fires the popupshown event.
+  MOZ_CAN_RUN_SCRIPT void MenuOpenedAsync();
+
+  // Called from mPendingAsyncMenuCloseRunnable asynchronously after
+  // MenuClosed(), so that it runs after any potential menuItemHit calls for
+  // clicked menu items. Fires popuphiding and popuphidden events. When calling
+  // this method, the caller must hold a strong reference to this object,
+  // because other references to this object can be dropped during the handling
+  // of the DOM event.
+  MOZ_CAN_RUN_SCRIPT void MenuClosedAsync();
+
+  // If mPendingAsyncMenuOpenRunnable is non-null, call MenuOpenedAsync() to
+  // send out the pending popupshown event.
+  // TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230)
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY void FlushMenuOpenedRunnable();
+
+  // If mPendingAsyncMenuCloseRunnable is non-null, call MenuClosedAsync() to
+  // send out pending popuphiding/popuphidden events.
+  // TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230)
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY void FlushMenuClosedRunnable();
+
+  // Make sure the NSMenu contains at least one item, even if mVisibleItemsCount
+  // is zero. Otherwise it won't open.
+  void InsertPlaceholderIfNeeded();
+  // Remove the placeholder before adding an item to mNativeNSMenu.
+  void RemovePlaceholderIfPresent();
+
+  nsCOMPtr<nsIContent> mContent;  // XUL <menu> or <menupopup>
+
+  // Contains nsMenuX and nsMenuItemX objects
+  nsTArray<MenuChild> mMenuChildren;
+
+  nsString mLabel;
+  uint32_t mVisibleItemsCount = 0;                     // cache
+  nsMenuParentX* mParent = nullptr;                    // [weak]
+  nsMenuGroupOwnerX* mMenuGroupOwner = nullptr;        // [weak]
+  nsMenuItemIconX::Listener* mIconListener = nullptr;  // [weak]
+  mozilla::UniquePtr<nsMenuItemIconX> mIcon;
+
+  Observer* mObserver = nullptr;  // non-owning pointer to our observer
+
+  // Non-null between a call to MenuOpened() and MenuOpenedAsync().
+  RefPtr<mozilla::CancelableRunnable> mPendingAsyncMenuOpenRunnable;
+
+  // Non-null between a call to MenuClosed() and MenuClosedAsync().
+  // This is asynchronous so that, if a menu item is clicked, we can fire
+  // popuphiding *after* we execute the menu item command. The macOS menu system
+  // calls menuWillClose *before* it calls menuItemHit.
+  RefPtr<mozilla::CancelableRunnable> mPendingAsyncMenuCloseRunnable;
+
+  struct PendingCommandEvent {
+    RefPtr<nsMenuItemX> mMenuItem;
+    NSEventModifierFlags mModifiers;
+    int16_t mButton;
+  };
+
+  // Any pending command events.
+  // These are queued by ActivateItemAfterClosing and run by MenuClosedAsync.
+  nsTArray<PendingCommandEvent> mPendingCommandEvents;
+
+  GeckoNSMenu* mNativeMenu = nil;     // [strong]
+  MenuDelegate* mMenuDelegate = nil;  // [strong]
+  // nsMenuX objects should always have a valid native menu item.
+  NSMenuItem* mNativeMenuItem = nil;  // [strong]
+
+  // Nothing() if no item is highlighted. The index only accounts for visible
+  // items.
+  mozilla::Maybe<uint32_t> mHighlightedItemIndex;
+
+  bool mIsEnabled = true;
+  bool mNeedsRebuild = true;
+
+  // Whether the native NSMenu is considered open.
+  // Also affected by MenuOpened() / MenuClosed() calls for simulated opening /
+  // closing.
+  bool mIsOpen = false;
+
+  // Whether the popup is open from Gecko's perspective, based on popupshowing /
+  // popuphiding events.
+  bool mIsOpenForGecko = false;
+
+  bool mVisible = true;
+
+  // true between an OnOpen() call that returned true, and the subsequent call
+  // to MenuOpened().
+  bool mDidFirePopupshowingAndIsApprovedToOpen = false;
+};
+
+#endif  // nsMenuX_h_
diff --git a/widget/cocoa/nsMenuX.mm b/widget/cocoa/nsMenuX.mm
new file mode 100644
index 0000000000..d6003c4faf
--- /dev/null
+++ b/widget/cocoa/nsMenuX.mm
@@ -0,0 +1,1490 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsMenuX.h"
+
+#include <_types/_uint32_t.h>
+#include <dlfcn.h>
+
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/EventDispatcher.h"
+#include "mozilla/MouseEvents.h"
+
+#include "MOZMenuOpeningCoordinator.h"
+#include "nsMenuItemX.h"
+#include "nsMenuUtilsX.h"
+#include "nsMenuItemIconX.h"
+
+#include "nsObjCExceptions.h"
+
+#include "nsComputedDOMStyle.h"
+#include "nsThreadUtils.h"
+#include "nsToolkit.h"
+#include "nsCocoaUtils.h"
+#include "nsCOMPtr.h"
+#include "prinrval.h"
+#include "nsString.h"
+#include "nsReadableUtils.h"
+#include "nsUnicharUtils.h"
+#include "nsGkAtoms.h"
+#include "nsCRT.h"
+#include "nsBaseWidget.h"
+
+#include "nsIContent.h"
+#include "nsIDocumentObserver.h"
+#include "nsIComponentManager.h"
+#include "nsIRollupListener.h"
+#include "nsIServiceManager.h"
+#include "nsXULPopupManager.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+static bool gConstructingMenu = false;
+static bool gMenuMethodsSwizzled = false;
+
+int32_t nsMenuX::sIndexingMenuLevel = 0;
+
+// TODO: It is unclear whether this is still needed.
+static void SwizzleDynamicIndexingMethods() {
+  if (gMenuMethodsSwizzled) {
+    return;
+  }
+
+  nsToolkit::SwizzleMethods([NSMenu class], @selector(_addItem:toTable:),
+                            @selector(nsMenuX_NSMenu_addItem:toTable:), true);
+  nsToolkit::SwizzleMethods([NSMenu class], @selector(_removeItem:fromTable:),
+                            @selector(nsMenuX_NSMenu_removeItem:fromTable:),
+                            true);
+  // On SnowLeopard the Shortcut framework (which contains the
+  // SCTGRLIndex class) is loaded on demand, whenever the user first opens
+  // a menu (which normally hasn't happened yet).  So we need to load it
+  // here explicitly.
+  dlopen("/System/Library/PrivateFrameworks/Shortcut.framework/Shortcut",
+         RTLD_LAZY);
+  Class SCTGRLIndexClass = ::NSClassFromString(@"SCTGRLIndex");
+  nsToolkit::SwizzleMethods(
+      SCTGRLIndexClass, @selector(indexMenuBarDynamically),
+      @selector(nsMenuX_SCTGRLIndex_indexMenuBarDynamically));
+
+  Class NSServicesMenuUpdaterClass =
+      ::NSClassFromString(@"_NSServicesMenuUpdater");
+  nsToolkit::SwizzleMethods(
+      NSServicesMenuUpdaterClass,
+      @selector(populateMenu:withServiceEntries:forDisplay:),
+      @selector(nsMenuX_populateMenu:withServiceEntries:forDisplay:));
+
+  gMenuMethodsSwizzled = true;
+}
+
+//
+// nsMenuX
+//
+
+nsMenuX::nsMenuX(nsMenuParentX* aParent, nsMenuGroupOwnerX* aMenuGroupOwner,
+                 nsIContent* aContent)
+    : mContent(aContent), mParent(aParent), mMenuGroupOwner(aMenuGroupOwner) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  MOZ_COUNT_CTOR(nsMenuX);
+
+  SwizzleDynamicIndexingMethods();
+
+  mMenuDelegate = [[MenuDelegate alloc] initWithGeckoMenu:this];
+
+  if (!nsMenuBarX::sNativeEventTarget) {
+    nsMenuBarX::sNativeEventTarget = [[NativeMenuItemTarget alloc] init];
+  }
+
+  bool shouldShowServices = false;
+  if (mContent->IsElement()) {
+    mContent->AsElement()->GetAttr(nsGkAtoms::label, mLabel);
+
+    shouldShowServices =
+        mContent->AsElement()->HasAttr(nsGkAtoms::showservicesmenu);
+  }
+  mNativeMenu = CreateMenuWithGeckoString(mLabel, shouldShowServices);
+
+  // register this menu to be notified when changes are made to our content
+  // object
+  NS_ASSERTION(mMenuGroupOwner, "No menu owner given, must have one");
+  mMenuGroupOwner->RegisterForContentChanges(mContent, this);
+
+  mVisible = !nsMenuUtilsX::NodeIsHiddenOrCollapsed(mContent);
+
+  NSString* newCocoaLabelString = nsMenuUtilsX::GetTruncatedCocoaLabel(mLabel);
+  mNativeMenuItem = [[NSMenuItem alloc] initWithTitle:newCocoaLabelString
+                                               action:nil
+                                        keyEquivalent:@""];
+  mNativeMenuItem.submenu = mNativeMenu;
+
+  SetEnabled(!mContent->IsElement() ||
+             !mContent->AsElement()->AttrValueIs(
+                 kNameSpaceID_None, nsGkAtoms::disabled, nsGkAtoms::_true,
+                 eCaseMatters));
+
+  // We call RebuildMenu here because keyboard commands are dependent upon
+  // native menu items being created. If we only call RebuildMenu when a menu
+  // is actually selected, then we can't access keyboard commands until the
+  // menu gets selected, which is bad.
+  RebuildMenu();
+
+  if (IsXULWindowMenu(mContent)) {
+    // Let the OS know that this is our Window menu.
+    NSApp.windowsMenu = mNativeMenu;
+  }
+
+  mIcon = MakeUnique<nsMenuItemIconX>(this);
+
+  if (mVisible) {
+    SetupIcon();
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+nsMenuX::~nsMenuX() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // Make sure a pending popupshown event isn't dropped.
+  FlushMenuOpenedRunnable();
+
+  if (mIsOpen) {
+    [mNativeMenu cancelTracking];
+    MOZMenuOpeningCoordinator.needToUnwindForMenuClosing = YES;
+  }
+
+  // Make sure pending popuphiding/popuphidden events aren't dropped.
+  FlushMenuClosedRunnable();
+
+  OnHighlightedItemChanged(Nothing());
+  RemoveAll();
+
+  mNativeMenu.delegate = nil;
+  [mNativeMenu release];
+  [mMenuDelegate release];
+  // autorelease the native menu item so that anything else happening to this
+  // object happens before the native menu item actually dies
+  [mNativeMenuItem autorelease];
+
+  DetachFromGroupOwnerRecursive();
+
+  MOZ_COUNT_DTOR(nsMenuX);
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuX::DetachFromGroupOwnerRecursive() {
+  if (!mMenuGroupOwner) {
+    // Don't recurse if this subtree is already detached.
+    // This avoids repeated recursion during the destruction of nested nsMenuX
+    // structures. Our invariant is: If we are detached, all of our contents are
+    // also detached.
+    return;
+  }
+
+  if (mMenuGroupOwner && mContent) {
+    mMenuGroupOwner->UnregisterForContentChanges(mContent);
+  }
+  mMenuGroupOwner = nullptr;
+
+  // Also detach all our children.
+  for (auto& child : mMenuChildren) {
+    child.match(
+        [](const RefPtr<nsMenuX>& aMenu) {
+          aMenu->DetachFromGroupOwnerRecursive();
+        },
+        [](const RefPtr<nsMenuItemX>& aMenuItem) {
+          aMenuItem->DetachFromGroupOwner();
+        });
+  }
+}
+
+void nsMenuX::OnMenuWillOpen(dom::Element* aPopupElement) {
+  RefPtr<nsMenuX> kungFuDeathGrip(this);
+  if (mObserver) {
+    mObserver->OnMenuWillOpen(aPopupElement);
+  }
+}
+
+void nsMenuX::OnMenuDidOpen(dom::Element* aPopupElement) {
+  RefPtr<nsMenuX> kungFuDeathGrip(this);
+  if (mObserver) {
+    mObserver->OnMenuDidOpen(aPopupElement);
+  }
+}
+
+void nsMenuX::OnMenuWillActivateItem(dom::Element* aPopupElement,
+                                     dom::Element* aMenuItemElement) {
+  RefPtr<nsMenuX> kungFuDeathGrip(this);
+  if (mObserver) {
+    mObserver->OnMenuWillActivateItem(aPopupElement, aMenuItemElement);
+  }
+}
+
+void nsMenuX::OnMenuClosed(dom::Element* aPopupElement) {
+  RefPtr<nsMenuX> kungFuDeathGrip(this);
+  if (mObserver) {
+    mObserver->OnMenuClosed(aPopupElement);
+  }
+}
+
+void nsMenuX::AddMenuChild(MenuChild&& aChild) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  WillInsertChild(aChild);
+  mMenuChildren.AppendElement(aChild);
+
+  bool isVisible = aChild.match(
+      [](const RefPtr<nsMenuX>& aMenu) { return aMenu->IsVisible(); },
+      [](const RefPtr<nsMenuItemX>& aMenuItem) {
+        return aMenuItem->IsVisible();
+      });
+  NSMenuItem* nativeItem = aChild.match(
+      [](const RefPtr<nsMenuX>& aMenu) { return aMenu->NativeNSMenuItem(); },
+      [](const RefPtr<nsMenuItemX>& aMenuItem) {
+        return aMenuItem->NativeNSMenuItem();
+      });
+
+  if (isVisible) {
+    RemovePlaceholderIfPresent();
+    [mNativeMenu addItem:nativeItem];
+    ++mVisibleItemsCount;
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuX::InsertMenuChild(MenuChild&& aChild) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  WillInsertChild(aChild);
+  size_t insertionIndex = FindInsertionIndex(aChild);
+  mMenuChildren.InsertElementAt(insertionIndex, aChild);
+
+  bool isVisible = aChild.match(
+      [](const RefPtr<nsMenuX>& aMenu) { return aMenu->IsVisible(); },
+      [](const RefPtr<nsMenuItemX>& aMenuItem) {
+        return aMenuItem->IsVisible();
+      });
+  if (isVisible) {
+    MenuChildChangedVisibility(aChild, true);
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuX::RemoveMenuChild(const MenuChild& aChild) {
+  bool isVisible = aChild.match(
+      [](const RefPtr<nsMenuX>& aMenu) { return aMenu->IsVisible(); },
+      [](const RefPtr<nsMenuItemX>& aMenuItem) {
+        return aMenuItem->IsVisible();
+      });
+  if (isVisible) {
+    MenuChildChangedVisibility(aChild, false);
+  }
+
+  WillRemoveChild(aChild);
+  mMenuChildren.RemoveElement(aChild);
+}
+
+size_t nsMenuX::FindInsertionIndex(const MenuChild& aChild) {
+  nsCOMPtr<nsIContent> menuPopup = GetMenuPopupContent();
+  MOZ_RELEASE_ASSERT(menuPopup);
+
+  RefPtr<nsIContent> insertedContent = aChild.match(
+      [](const RefPtr<nsMenuX>& aMenu) { return aMenu->Content(); },
+      [](const RefPtr<nsMenuItemX>& aMenuItem) {
+        return aMenuItem->Content();
+      });
+
+  MOZ_RELEASE_ASSERT(insertedContent->GetParent() == menuPopup);
+
+  // Iterate over menuPopup's children (insertedContent's siblings) until we
+  // encounter insertedContent. At the same time, keep track of the index in
+  // mMenuChildren.
+  size_t index = 0;
+  for (nsIContent* child = menuPopup->GetFirstChild();
+       child && index < mMenuChildren.Length();
+       child = child->GetNextSibling()) {
+    if (child == insertedContent) {
+      break;
+    }
+
+    RefPtr<nsIContent> contentAtIndex = mMenuChildren[index].match(
+        [](const RefPtr<nsMenuX>& aMenu) { return aMenu->Content(); },
+        [](const RefPtr<nsMenuItemX>& aMenuItem) {
+          return aMenuItem->Content();
+        });
+    if (child == contentAtIndex) {
+      index++;
+    }
+  }
+
+  return index;
+}
+
+// Includes all items, including hidden/collapsed ones
+uint32_t nsMenuX::GetItemCount() { return mMenuChildren.Length(); }
+
+// Includes all items, including hidden/collapsed ones
+mozilla::Maybe<nsMenuX::MenuChild> nsMenuX::GetItemAt(uint32_t aPos) {
+  if (aPos >= (uint32_t)mMenuChildren.Length()) {
+    return {};
+  }
+
+  return Some(mMenuChildren[aPos]);
+}
+
+// Only includes visible items
+nsresult nsMenuX::GetVisibleItemCount(uint32_t& aCount) {
+  aCount = mVisibleItemsCount;
+  return NS_OK;
+}
+
+// Only includes visible items. Note that this is provides O(N) access
+// If you need to iterate or search, consider using GetItemAt and doing your own
+// filtering
+Maybe<nsMenuX::MenuChild> nsMenuX::GetVisibleItemAt(uint32_t aPos) {
+  uint32_t count = mMenuChildren.Length();
+  if (aPos >= mVisibleItemsCount || aPos >= count) {
+    return {};
+  }
+
+  // If there are no invisible items, can provide direct access
+  if (mVisibleItemsCount == count) {
+    return GetItemAt(aPos);
+  }
+
+  // Otherwise, traverse the array until we find the the item we're looking for.
+  uint32_t visibleNodeIndex = 0;
+  for (uint32_t i = 0; i < count; i++) {
+    MenuChild item = *GetItemAt(i);
+    RefPtr<nsIContent> content = item.match(
+        [](const RefPtr<nsMenuX>& aMenu) { return aMenu->Content(); },
+        [](const RefPtr<nsMenuItemX>& aMenuItem) {
+          return aMenuItem->Content();
+        });
+    if (!nsMenuUtilsX::NodeIsHiddenOrCollapsed(content)) {
+      if (aPos == visibleNodeIndex) {
+        // we found the visible node we're looking for, return it
+        return Some(item);
+      }
+      visibleNodeIndex++;
+    }
+  }
+
+  return {};
+}
+
+Maybe<nsMenuX::MenuChild> nsMenuX::GetItemForElement(
+    Element* aMenuChildElement) {
+  for (auto& child : mMenuChildren) {
+    RefPtr<nsIContent> content = child.match(
+        [](const RefPtr<nsMenuX>& aMenu) { return aMenu->Content(); },
+        [](const RefPtr<nsMenuItemX>& aMenuItem) {
+          return aMenuItem->Content();
+        });
+    if (content == aMenuChildElement) {
+      return Some(child);
+    }
+  }
+  return {};
+}
+
+nsresult nsMenuX::RemoveAll() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  [mNativeMenu removeAllItems];
+
+  for (auto& child : mMenuChildren) {
+    WillRemoveChild(child);
+  }
+
+  mMenuChildren.Clear();
+  mVisibleItemsCount = 0;
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuX::WillInsertChild(const MenuChild& aChild) {
+  if (aChild.is<RefPtr<nsMenuX>>()) {
+    aChild.as<RefPtr<nsMenuX>>()->SetObserver(this);
+  }
+}
+
+void nsMenuX::WillRemoveChild(const MenuChild& aChild) {
+  aChild.match(
+      [](const RefPtr<nsMenuX>& aMenu) {
+        aMenu->DetachFromGroupOwnerRecursive();
+        aMenu->DetachFromParent();
+        aMenu->SetObserver(nullptr);
+      },
+      [](const RefPtr<nsMenuItemX>& aMenuItem) {
+        aMenuItem->DetachFromGroupOwner();
+        aMenuItem->DetachFromParent();
+      });
+}
+
+void nsMenuX::MenuOpened() {
+  if (mIsOpen) {
+    return;
+  }
+
+  // Make sure we fire any pending popupshown / popuphiding / popuphidden events
+  // first.
+  FlushMenuOpenedRunnable();
+  FlushMenuClosedRunnable();
+
+  if (!mDidFirePopupshowingAndIsApprovedToOpen) {
+    // Fire popupshowing now.
+    bool approvedToOpen = OnOpen();
+    if (!approvedToOpen) {
+      // We can only stop menus from opening which we open ourselves. We cannot
+      // stop menubar root menus or menu submenus from opening. For context
+      // menus, we can call OnOpen() before we ask the system to open the menu.
+      NS_WARNING("The popupshowing event had preventDefault() called on it, "
+                 "but in MenuOpened() it "
+                 "is too late to stop the menu from opening.");
+    }
+  }
+
+  mIsOpen = true;
+
+  // Reset mDidFirePopupshowingAndIsApprovedToOpen for the next menu opening.
+  mDidFirePopupshowingAndIsApprovedToOpen = false;
+
+  if (mNeedsRebuild) {
+    OnHighlightedItemChanged(Nothing());
+    RemoveAll();
+    RebuildMenu();
+  }
+
+  // Fire the popupshown event in MenuOpenedAsync.
+  // MenuOpened() is called during menuWillOpen, and if cancelTracking is called
+  // now, menuDidClose will not be called. The runnable object must not hold a
+  // strong reference to the nsMenuX, so that there is no reference cycle.
+  class MenuOpenedAsyncRunnable final : public mozilla::CancelableRunnable {
+   public:
+    explicit MenuOpenedAsyncRunnable(nsMenuX* aMenu)
+        : CancelableRunnable("MenuOpenedAsyncRunnable"), mMenu(aMenu) {}
+
+    // TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230, bug 1535398)
+    MOZ_CAN_RUN_SCRIPT_BOUNDARY nsresult Run() override {
+      if (RefPtr<nsMenuX> menu = mMenu) {
+        menu->MenuOpenedAsync();
+        mMenu = nullptr;
+      }
+      return NS_OK;
+    }
+    nsresult Cancel() override {
+      mMenu = nullptr;
+      return NS_OK;
+    }
+
+   private:
+    nsMenuX* mMenu;  // weak, cleared by Cancel() and Run()
+  };
+  mPendingAsyncMenuOpenRunnable = new MenuOpenedAsyncRunnable(this);
+  NS_DispatchToCurrentThread(mPendingAsyncMenuOpenRunnable);
+}
+
+void nsMenuX::FlushMenuOpenedRunnable() {
+  if (mPendingAsyncMenuOpenRunnable) {
+    MenuOpenedAsync();
+  }
+}
+
+void nsMenuX::MenuOpenedAsync() {
+  if (mPendingAsyncMenuOpenRunnable) {
+    mPendingAsyncMenuOpenRunnable->Cancel();
+    mPendingAsyncMenuOpenRunnable = nullptr;
+  }
+
+  mIsOpenForGecko = true;
+
+  // Open the node.
+  if (mContent->IsElement()) {
+    mContent->AsElement()->SetAttr(kNameSpaceID_None, nsGkAtoms::open,
+                                   u"true"_ns, true);
+  }
+
+  RefPtr<nsIContent> popupContent = GetMenuPopupContent();
+
+  // Notify our observer.
+  if (mObserver && popupContent) {
+    mObserver->OnMenuDidOpen(popupContent->AsElement());
+  }
+
+  // Fire popupshown.
+  nsEventStatus status = nsEventStatus_eIgnore;
+  WidgetMouseEvent event(true, eXULPopupShown, nullptr,
+                         WidgetMouseEvent::eReal);
+  RefPtr<nsIContent> dispatchTo = popupContent ? popupContent : mContent;
+  EventDispatcher::Dispatch(dispatchTo, nullptr, &event, nullptr, &status);
+}
+
+void nsMenuX::MenuClosed() {
+  if (!mIsOpen) {
+    return;
+  }
+
+  // Make sure we fire any pending popupshown events first.
+  FlushMenuOpenedRunnable();
+
+  // If any of our submenus were opened programmatically, make sure they get
+  // closed first.
+  for (auto& child : mMenuChildren) {
+    if (child.is<RefPtr<nsMenuX>>()) {
+      child.as<RefPtr<nsMenuX>>()->MenuClosed();
+    }
+  }
+
+  mIsOpen = false;
+
+  // Do the rest of the MenuClosed work in MenuClosedAsync.
+  // MenuClosed() is called from -[NSMenuDelegate menuDidClose:]. If a menuitem
+  // was clicked, menuDidClose is called *before* menuItemHit for the clicked
+  // menu item is called. This runnable will be canceled if ~nsMenuX runs before
+  // the runnable. The runnable object must not hold a strong reference to the
+  // nsMenuX, so that there is no reference cycle.
+  class MenuClosedAsyncRunnable final : public mozilla::CancelableRunnable {
+   public:
+    explicit MenuClosedAsyncRunnable(nsMenuX* aMenu)
+        : CancelableRunnable("MenuClosedAsyncRunnable"), mMenu(aMenu) {}
+
+    // TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230, bug 1535398)
+    MOZ_CAN_RUN_SCRIPT_BOUNDARY nsresult Run() override {
+      if (RefPtr<nsMenuX> menu = mMenu) {
+        menu->MenuClosedAsync();
+        mMenu = nullptr;
+      }
+      return NS_OK;
+    }
+    nsresult Cancel() override {
+      mMenu = nullptr;
+      return NS_OK;
+    }
+
+   private:
+    nsMenuX* mMenu;  // weak, cleared by Cancel() and Run()
+  };
+
+  mPendingAsyncMenuCloseRunnable = new MenuClosedAsyncRunnable(this);
+
+  NS_DispatchToCurrentThread(mPendingAsyncMenuCloseRunnable);
+}
+
+void nsMenuX::FlushMenuClosedRunnable() {
+  // If any of our submenus have a pending menu closed runnable, make sure those
+  // run first.
+  for (auto& child : mMenuChildren) {
+    if (child.is<RefPtr<nsMenuX>>()) {
+      child.as<RefPtr<nsMenuX>>()->FlushMenuClosedRunnable();
+    }
+  }
+
+  if (mPendingAsyncMenuCloseRunnable) {
+    MenuClosedAsync();
+  }
+}
+
+void nsMenuX::MenuClosedAsync() {
+  if (mPendingAsyncMenuCloseRunnable) {
+    mPendingAsyncMenuCloseRunnable->Cancel();
+    mPendingAsyncMenuCloseRunnable = nullptr;
+  }
+
+  // If we have pending command events, run those first.
+  nsTArray<PendingCommandEvent> events = std::move(mPendingCommandEvents);
+  for (auto& event : events) {
+    event.mMenuItem->DoCommand(event.mModifiers, event.mButton);
+  }
+
+  // Make sure no item is highlighted.
+  OnHighlightedItemChanged(Nothing());
+
+  nsCOMPtr<nsIContent> popupContent = GetMenuPopupContent();
+  nsCOMPtr<nsIContent> dispatchTo = popupContent ? popupContent : mContent;
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  WidgetMouseEvent popupHiding(true, eXULPopupHiding, nullptr,
+                               WidgetMouseEvent::eReal);
+  EventDispatcher::Dispatch(dispatchTo, nullptr, &popupHiding, nullptr,
+                            &status);
+
+  mIsOpenForGecko = false;
+
+  if (mContent->IsElement()) {
+    mContent->AsElement()->UnsetAttr(kNameSpaceID_None, nsGkAtoms::open, true);
+  }
+
+  WidgetMouseEvent popupHidden(true, eXULPopupHidden, nullptr,
+                               WidgetMouseEvent::eReal);
+  EventDispatcher::Dispatch(dispatchTo, nullptr, &popupHidden, nullptr,
+                            &status);
+
+  // Notify our observer.
+  if (mObserver && popupContent) {
+    mObserver->OnMenuClosed(popupContent->AsElement());
+  }
+}
+
+void nsMenuX::ActivateItemAfterClosing(RefPtr<nsMenuItemX>&& aItem,
+                                       NSEventModifierFlags aModifiers,
+                                       int16_t aButton) {
+  if (mIsOpenForGecko) {
+    // Queue the event into mPendingCommandEvents. We will call aItem->DoCommand
+    // in MenuClosedAsync(). We rely on the assumption that MenuClosedAsync will
+    // run soon.
+    mPendingCommandEvents.AppendElement(
+        PendingCommandEvent{std::move(aItem), aModifiers, aButton});
+  } else {
+    // The menu item was activated outside of a regular open / activate / close
+    // sequence. This happens in multiple cases:
+    //  - When a menu item is activated by a keyboard shortcut while all windows
+    //  are closed
+    //    (otherwise those shortcuts go through Gecko's manual keyboard
+    //    handling)
+    //  - When a menu item in the Dock menu is clicked
+    //  - During native menu tests
+    //
+    // Run the command synchronously.
+    aItem->DoCommand(aModifiers, aButton);
+  }
+}
+
+bool nsMenuX::Close() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  if (mDidFirePopupshowingAndIsApprovedToOpen && !mIsOpen) {
+    // Close is being called right after this menu was opened, but before
+    // MenuOpened() had a chance to run. Call it here so that we can go through
+    // the entire popupshown -> popuphiding -> popuphidden sequence. Some
+    // callers expect to get a popuphidden event even if they close the popup
+    // before it was fully open.
+    MenuOpened();
+  }
+
+  FlushMenuOpenedRunnable();
+
+  bool wasOpen = mIsOpenForGecko;
+
+  if (mIsOpen) {
+    // Close the menu.
+    // We usually don't get here during normal Firefox usage: If the user closes
+    // the menu by clicking an item, or by clicking outside the menu, or by
+    // pressing escape, then the menu gets closed by macOS, and not by a call to
+    // nsMenuX::Close(). If we do get here, it's usually because we're running
+    // an automated test. Close the menu without the fade-out animation so that
+    // we don't unnecessarily slow down the automated tests.
+    [mNativeMenu cancelTrackingWithoutAnimation];
+    MOZMenuOpeningCoordinator.needToUnwindForMenuClosing = YES;
+
+    // Handle closing synchronously.
+    MenuClosed();
+  }
+
+  FlushMenuClosedRunnable();
+
+  return wasOpen;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuX::OnHighlightedItemChanged(
+    const Maybe<uint32_t>& aNewHighlightedIndex) {
+  if (mHighlightedItemIndex == aNewHighlightedIndex) {
+    return;
+  }
+
+  if (mHighlightedItemIndex) {
+    Maybe<nsMenuX::MenuChild> target = GetVisibleItemAt(*mHighlightedItemIndex);
+    if (target && target->is<RefPtr<nsMenuItemX>>()) {
+      bool handlerCalledPreventDefault;  // but we don't actually care
+      target->as<RefPtr<nsMenuItemX>>()->DispatchDOMEvent(
+          u"DOMMenuItemInactive"_ns, &handlerCalledPreventDefault);
+    }
+  }
+  if (aNewHighlightedIndex) {
+    Maybe<nsMenuX::MenuChild> target = GetVisibleItemAt(*aNewHighlightedIndex);
+    if (target && target->is<RefPtr<nsMenuItemX>>()) {
+      bool handlerCalledPreventDefault;  // but we don't actually care
+      target->as<RefPtr<nsMenuItemX>>()->DispatchDOMEvent(
+          u"DOMMenuItemActive"_ns, &handlerCalledPreventDefault);
+    }
+  }
+  mHighlightedItemIndex = aNewHighlightedIndex;
+}
+
+void nsMenuX::OnWillActivateItem(NSMenuItem* aItem) {
+  if (!mIsOpenForGecko) {
+    return;
+  }
+
+  if (mMenuGroupOwner && mObserver) {
+    nsMenuItemX* item =
+        mMenuGroupOwner->GetMenuItemForCommandID(uint32_t(aItem.tag));
+    if (item && item->Content()->IsElement()) {
+      RefPtr<dom::Element> itemElement = item->Content()->AsElement();
+      if (nsCOMPtr<nsIContent> popupContent = GetMenuPopupContent()) {
+        mObserver->OnMenuWillActivateItem(popupContent->AsElement(),
+                                          itemElement);
+      }
+    }
+  }
+}
+
+// Flushes style.
+static NSUserInterfaceLayoutDirection DirectionForElement(
+    dom::Element* aElement) {
+  // Get the direction from the computed style so that inheritance into submenus
+  // is respected. aElement may not have a frame.
+  RefPtr<const ComputedStyle> sc =
+      nsComputedDOMStyle::GetComputedStyle(aElement);
+  if (!sc) {
+    return NSApp.userInterfaceLayoutDirection;
+  }
+
+  switch (sc->StyleVisibility()->mDirection) {
+    case StyleDirection::Ltr:
+      return NSUserInterfaceLayoutDirectionLeftToRight;
+    case StyleDirection::Rtl:
+      return NSUserInterfaceLayoutDirectionRightToLeft;
+  }
+}
+
+void nsMenuX::RebuildMenu() {
+  MOZ_RELEASE_ASSERT(mNeedsRebuild);
+  gConstructingMenu = true;
+
+  // Retrieve our menupopup.
+  nsCOMPtr<nsIContent> menuPopup = GetMenuPopupContent();
+  if (!menuPopup) {
+    gConstructingMenu = false;
+    return;
+  }
+
+  if (menuPopup->IsElement()) {
+    mNativeMenu.userInterfaceLayoutDirection =
+        DirectionForElement(menuPopup->AsElement());
+  }
+
+  // Iterate over the kids
+  for (nsIContent* child = menuPopup->GetFirstChild(); child;
+       child = child->GetNextSibling()) {
+    if (Maybe<MenuChild> menuChild = CreateMenuChild(child)) {
+      AddMenuChild(std::move(*menuChild));
+    }
+  }  // for each menu item
+
+  InsertPlaceholderIfNeeded();
+
+  gConstructingMenu = false;
+  mNeedsRebuild = false;
+}
+
+void nsMenuX::InsertPlaceholderIfNeeded() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  if ([mNativeMenu numberOfItems] == 0) {
+    MOZ_RELEASE_ASSERT(mVisibleItemsCount == 0);
+    NSMenuItem* item = [[NSMenuItem alloc] initWithTitle:@""
+                                                  action:nil
+                                           keyEquivalent:@""];
+    item.enabled = NO;
+    item.view =
+        [[[NSView alloc] initWithFrame:NSMakeRect(0, 0, 150, 1)] autorelease];
+    [mNativeMenu addItem:item];
+    [item release];
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuX::RemovePlaceholderIfPresent() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  if (mVisibleItemsCount == 0 && [mNativeMenu numberOfItems] == 1) {
+    // Remove the placeholder.
+    [mNativeMenu removeItemAtIndex:0];
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuX::SetRebuild(bool aNeedsRebuild) {
+  if (!gConstructingMenu) {
+    mNeedsRebuild = aNeedsRebuild;
+    if (mParent && mParent->AsMenuBar()) {
+      mParent->AsMenuBar()->SetNeedsRebuild();
+    }
+  }
+}
+
+nsresult nsMenuX::SetEnabled(bool aIsEnabled) {
+  if (aIsEnabled != mIsEnabled) {
+    // we always want to rebuild when this changes
+    mIsEnabled = aIsEnabled;
+    mNativeMenuItem.enabled = mIsEnabled;
+  }
+  return NS_OK;
+}
+
+nsresult nsMenuX::GetEnabled(bool* aIsEnabled) {
+  NS_ENSURE_ARG_POINTER(aIsEnabled);
+  *aIsEnabled = mIsEnabled;
+  return NS_OK;
+}
+
+GeckoNSMenu* nsMenuX::CreateMenuWithGeckoString(nsString& aMenuTitle,
+                                                bool aShowServices) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  NSString* title = [NSString stringWithCharacters:(UniChar*)aMenuTitle.get()
+                                            length:aMenuTitle.Length()];
+  GeckoNSMenu* myMenu = [[GeckoNSMenu alloc] initWithTitle:title];
+  myMenu.delegate = mMenuDelegate;
+
+  // We don't want this menu to auto-enable menu items because then Cocoa
+  // overrides our decisions and things get incorrectly enabled/disabled.
+  myMenu.autoenablesItems = NO;
+
+  // Only show "Services", "Autofill" and similar entries provided by macOS
+  // if our caller wants them:
+  myMenu.allowsContextMenuPlugIns = aShowServices;
+
+  // we used to install Carbon event handlers here, but since NSMenu* doesn't
+  // create its underlying MenuRef until just before display, we delay until
+  // that happens. Now we install the event handlers when Cocoa notifies
+  // us that a menu is about to display - see the Cocoa MenuDelegate class.
+
+  return myMenu;
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+Maybe<nsMenuX::MenuChild> nsMenuX::CreateMenuChild(nsIContent* aContent) {
+  if (aContent->IsAnyOfXULElements(nsGkAtoms::menuitem,
+                                   nsGkAtoms::menuseparator)) {
+    return Some(MenuChild(CreateMenuItem(aContent)));
+  }
+  if (aContent->IsXULElement(nsGkAtoms::menu)) {
+    return Some(
+        MenuChild(MakeRefPtr<nsMenuX>(this, mMenuGroupOwner, aContent)));
+  }
+  return {};
+}
+
+RefPtr<nsMenuItemX> nsMenuX::CreateMenuItem(nsIContent* aMenuItemContent) {
+  MOZ_RELEASE_ASSERT(aMenuItemContent);
+
+  nsAutoString menuitemName;
+  if (aMenuItemContent->IsElement()) {
+    aMenuItemContent->AsElement()->GetAttr(nsGkAtoms::label, menuitemName);
+  }
+
+  EMenuItemType itemType = eRegularMenuItemType;
+  if (aMenuItemContent->IsXULElement(nsGkAtoms::menuseparator)) {
+    itemType = eSeparatorMenuItemType;
+  } else if (aMenuItemContent->IsElement()) {
+    static Element::AttrValuesArray strings[] = {nsGkAtoms::checkbox,
+                                                 nsGkAtoms::radio, nullptr};
+    switch (aMenuItemContent->AsElement()->FindAttrValueIn(
+        kNameSpaceID_None, nsGkAtoms::type, strings, eCaseMatters)) {
+      case 0:
+        itemType = eCheckboxMenuItemType;
+        break;
+      case 1:
+        itemType = eRadioMenuItemType;
+        break;
+    }
+  }
+
+  return MakeRefPtr<nsMenuItemX>(this, menuitemName, itemType, mMenuGroupOwner,
+                                 aMenuItemContent);
+}
+
+// This menu is about to open. Returns false if the handler wants to stop the
+// opening of the menu.
+bool nsMenuX::OnOpen() {
+  if (mDidFirePopupshowingAndIsApprovedToOpen) {
+    return true;
+  }
+
+  if (mIsOpen) {
+    NS_WARNING("nsMenuX::OnOpen() called while the menu is already considered "
+               "to be open. This "
+               "seems odd.");
+  }
+
+  RefPtr<nsIContent> popupContent = GetMenuPopupContent();
+
+  if (mObserver && popupContent) {
+    mObserver->OnMenuWillOpen(popupContent->AsElement());
+  }
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  WidgetMouseEvent event(true, eXULPopupShowing, nullptr,
+                         WidgetMouseEvent::eReal);
+
+  nsresult rv = NS_OK;
+  RefPtr<nsIContent> dispatchTo = popupContent ? popupContent : mContent;
+  rv = EventDispatcher::Dispatch(dispatchTo, nullptr, &event, nullptr, &status);
+  if (NS_FAILED(rv) || status == nsEventStatus_eConsumeNoDefault) {
+    return false;
+  }
+
+  DidFirePopupShowing();
+
+  return true;
+}
+
+void nsMenuX::DidFirePopupShowing() {
+  mDidFirePopupshowingAndIsApprovedToOpen = true;
+
+  // If the open is going to succeed we need to walk our menu items, checking to
+  // see if any of them have a command attribute. If so, several attributes
+  // must potentially be updated.
+
+  nsCOMPtr<nsIContent> popupContent = GetMenuPopupContent();
+  if (!popupContent) {
+    return;
+  }
+
+  nsXULPopupManager* pm = nsXULPopupManager::GetInstance();
+  if (pm) {
+    pm->UpdateMenuItems(popupContent->AsElement());
+  }
+}
+
+// Find the |menupopup| child in the |popup| representing this menu. It should
+// be one of a very few children so we won't be iterating over a bazillion menu
+// items to find it (so the strcmp won't kill us).
+already_AddRefed<nsIContent> nsMenuX::GetMenuPopupContent() {
+  // Check to see if we are a "menupopup" node (if we are a native menu).
+  if (mContent->IsXULElement(nsGkAtoms::menupopup)) {
+    return do_AddRef(mContent);
+  }
+
+  // Otherwise check our child nodes.
+
+  for (RefPtr<nsIContent> child = mContent->GetFirstChild(); child;
+       child = child->GetNextSibling()) {
+    if (child->IsXULElement(nsGkAtoms::menupopup)) {
+      return child.forget();
+    }
+  }
+
+  return nullptr;
+}
+
+bool nsMenuX::IsXULHelpMenu(nsIContent* aMenuContent) {
+  bool retval = false;
+  if (aMenuContent && aMenuContent->IsElement()) {
+    nsAutoString id;
+    aMenuContent->AsElement()->GetAttr(nsGkAtoms::id, id);
+    if (id.Equals(u"helpMenu"_ns)) {
+      retval = true;
+    }
+  }
+  return retval;
+}
+
+bool nsMenuX::IsXULWindowMenu(nsIContent* aMenuContent) {
+  bool retval = false;
+  if (aMenuContent && aMenuContent->IsElement()) {
+    nsAutoString id;
+    aMenuContent->AsElement()->GetAttr(nsGkAtoms::id, id);
+    if (id.Equals(u"windowMenu"_ns)) {
+      retval = true;
+    }
+  }
+  return retval;
+}
+
+//
+// nsChangeObserver
+//
+
+void nsMenuX::ObserveAttributeChanged(dom::Document* aDocument,
+                                      nsIContent* aContent,
+                                      nsAtom* aAttribute) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  // ignore the |open| attribute, which is by far the most common
+  if (gConstructingMenu || (aAttribute == nsGkAtoms::open)) {
+    return;
+  }
+
+  if (aAttribute == nsGkAtoms::disabled) {
+    SetEnabled(!mContent->AsElement()->AttrValueIs(
+        kNameSpaceID_None, nsGkAtoms::disabled, nsGkAtoms::_true,
+        eCaseMatters));
+  } else if (aAttribute == nsGkAtoms::label) {
+    mContent->AsElement()->GetAttr(nsGkAtoms::label, mLabel);
+    NSString* newCocoaLabelString =
+        nsMenuUtilsX::GetTruncatedCocoaLabel(mLabel);
+    mNativeMenu.title = newCocoaLabelString;
+    mNativeMenuItem.title = newCocoaLabelString;
+  } else if (aAttribute == nsGkAtoms::hidden ||
+             aAttribute == nsGkAtoms::collapsed) {
+    SetRebuild(true);
+
+    bool newVisible = !nsMenuUtilsX::NodeIsHiddenOrCollapsed(mContent);
+
+    // don't do anything if the state is correct already
+    if (newVisible == mVisible) {
+      return;
+    }
+
+    mVisible = newVisible;
+    if (mParent) {
+      RefPtr<nsMenuX> self = this;
+      mParent->MenuChildChangedVisibility(MenuChild(self), newVisible);
+    }
+    if (mVisible) {
+      SetupIcon();
+    }
+  } else if (aAttribute == nsGkAtoms::image) {
+    SetupIcon();
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+void nsMenuX::ObserveContentRemoved(dom::Document* aDocument,
+                                    nsIContent* aContainer, nsIContent* aChild,
+                                    nsIContent* aPreviousSibling) {
+  if (gConstructingMenu) {
+    return;
+  }
+
+  SetRebuild(true);
+  mMenuGroupOwner->UnregisterForContentChanges(aChild);
+
+  if (!mIsOpen) {
+    // We will update the menu contents the next time the menu is opened.
+    return;
+  }
+
+  // The menu is currently open. Remove the child from mMenuChildren and from
+  // our NSMenu.
+  nsCOMPtr<nsIContent> popupContent = GetMenuPopupContent();
+  if (popupContent && aContainer == popupContent && aChild->IsElement()) {
+    if (Maybe<MenuChild> child = GetItemForElement(aChild->AsElement())) {
+      RemoveMenuChild(*child);
+    }
+  }
+}
+
+void nsMenuX::ObserveContentInserted(dom::Document* aDocument,
+                                     nsIContent* aContainer,
+                                     nsIContent* aChild) {
+  if (gConstructingMenu) {
+    return;
+  }
+
+  SetRebuild(true);
+
+  if (!mIsOpen) {
+    // We will update the menu contents the next time the menu is opened.
+    return;
+  }
+
+  // The menu is currently open. Insert the child into mMenuChildren and into
+  // our NSMenu.
+  nsCOMPtr<nsIContent> popupContent = GetMenuPopupContent();
+  if (popupContent && aContainer == popupContent) {
+    if (Maybe<MenuChild> child = CreateMenuChild(aChild)) {
+      InsertMenuChild(std::move(*child));
+    }
+  }
+}
+
+void nsMenuX::SetupIcon() {
+  mIcon->SetupIcon(mContent);
+  mNativeMenuItem.image = mIcon->GetIconImage();
+}
+
+void nsMenuX::IconUpdated() {
+  mNativeMenuItem.image = mIcon->GetIconImage();
+  if (mIconListener) {
+    mIconListener->IconUpdated();
+  }
+}
+
+void nsMenuX::MenuChildChangedVisibility(const MenuChild& aChild,
+                                         bool aIsVisible) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  NSMenuItem* nativeItem = aChild.match(
+      [](const RefPtr<nsMenuX>& aMenu) { return aMenu->NativeNSMenuItem(); },
+      [](const RefPtr<nsMenuItemX>& aMenuItem) {
+        return aMenuItem->NativeNSMenuItem();
+      });
+  if (aIsVisible) {
+    MOZ_RELEASE_ASSERT(
+        !nativeItem.menu,
+        "The native item should not be in a menu while it is hidden");
+    RemovePlaceholderIfPresent();
+    NSInteger insertionPoint = CalculateNativeInsertionPoint(aChild);
+    [mNativeMenu insertItem:nativeItem atIndex:insertionPoint];
+    mVisibleItemsCount++;
+  } else {
+    MOZ_RELEASE_ASSERT(
+        [mNativeMenu indexOfItem:nativeItem] != -1,
+        "The native item should be in this menu while it is visible");
+    [mNativeMenu removeItem:nativeItem];
+    mVisibleItemsCount--;
+    InsertPlaceholderIfNeeded();
+  }
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+NSInteger nsMenuX::CalculateNativeInsertionPoint(const MenuChild& aChild) {
+  NSInteger insertionPoint = 0;
+  for (auto& currItem : mMenuChildren) {
+    // Using GetItemAt instead of GetVisibleItemAt to avoid O(N^2)
+    if (currItem == aChild) {
+      return insertionPoint;
+    }
+    NSMenuItem* nativeItem = currItem.match(
+        [](const RefPtr<nsMenuX>& aMenu) { return aMenu->NativeNSMenuItem(); },
+        [](const RefPtr<nsMenuItemX>& aMenuItem) {
+          return aMenuItem->NativeNSMenuItem();
+        });
+    // Only count visible items.
+    if (nativeItem.menu) {
+      insertionPoint++;
+    }
+  }
+  return insertionPoint;
+}
+
+void nsMenuX::Dump(uint32_t aIndent) const {
+  printf(
+      "%*s - menu [%p] %-16s <%s>", aIndent * 2, "", this,
+      mLabel.IsEmpty() ? "(empty label)" : NS_ConvertUTF16toUTF8(mLabel).get(),
+      NS_ConvertUTF16toUTF8(mContent->NodeName()).get());
+  if (mNeedsRebuild) {
+    printf(" [NeedsRebuild]");
+  }
+  if (mIsOpen) {
+    printf(" [Open]");
+  }
+  if (mVisible) {
+    printf(" [Visible]");
+  }
+  if (mIsEnabled) {
+    printf(" [IsEnabled]");
+  }
+  printf(" (%d visible items)", int(mVisibleItemsCount));
+  printf("\n");
+  for (const auto& subitem : mMenuChildren) {
+    subitem.match(
+        [=](const RefPtr<nsMenuX>& aMenu) { aMenu->Dump(aIndent + 1); },
+        [=](const RefPtr<nsMenuItemX>& aMenuItem) {
+          aMenuItem->Dump(aIndent + 1);
+        });
+  }
+}
+
+//
+// MenuDelegate Objective-C class, used to set up Carbon events
+//
+
+@implementation MenuDelegate
+
+- (id)initWithGeckoMenu:(nsMenuX*)geckoMenu {
+  if ((self = [super init])) {
+    NS_ASSERTION(geckoMenu, "Cannot initialize native menu delegate with NULL "
+                            "gecko menu! Will crash!");
+    mGeckoMenu = geckoMenu;
+    mBlocksToRunWhenOpen = [[NSMutableArray alloc] init];
+  }
+  return self;
+}
+
+- (void)dealloc {
+  [mBlocksToRunWhenOpen release];
+  [super dealloc];
+}
+
+- (void)runBlockWhenOpen:(void (^)())block {
+  [mBlocksToRunWhenOpen addObject:[[block copy] autorelease]];
+}
+
+- (void)menu:(NSMenu*)aMenu willHighlightItem:(NSMenuItem*)aItem {
+  if (!aMenu || !mGeckoMenu) {
+    return;
+  }
+
+  Maybe<uint32_t> index =
+      aItem ? Some(static_cast<uint32_t>([aMenu indexOfItem:aItem]))
+            : Nothing();
+  mGeckoMenu->OnHighlightedItemChanged(index);
+}
+
+- (void)menuWillOpen:(NSMenu*)menu {
+  for (void (^block)() in mBlocksToRunWhenOpen) {
+    block();
+  }
+  [mBlocksToRunWhenOpen removeAllObjects];
+
+  if (!mGeckoMenu) {
+    return;
+  }
+
+  // Don't do anything while the OS is (re)indexing our menus (on Leopard and
+  // higher).  This stops the Help menu from being able to search in our
+  // menus, but it also resolves many other problems.
+  if (nsMenuX::sIndexingMenuLevel > 0) {
+    return;
+  }
+
+  // Hold a strong reference to mGeckoMenu while calling its methods.
+  RefPtr<nsMenuX> geckoMenu = mGeckoMenu;
+  geckoMenu->MenuOpened();
+}
+
+- (void)menuDidClose:(NSMenu*)menu {
+  if (!mGeckoMenu) {
+    return;
+  }
+
+  // Don't do anything while the OS is (re)indexing our menus (on Leopard and
+  // higher).  This stops the Help menu from being able to search in our
+  // menus, but it also resolves many other problems.
+  if (nsMenuX::sIndexingMenuLevel > 0) {
+    return;
+  }
+
+  // Hold a strong reference to mGeckoMenu while calling its methods.
+  RefPtr<nsMenuX> geckoMenu = mGeckoMenu;
+  geckoMenu->MenuClosed();
+}
+
+// This is called after menuDidClose:.
+- (void)menu:(NSMenu*)aMenu willActivateItem:(NSMenuItem*)aItem {
+  if (!mGeckoMenu) {
+    return;
+  }
+
+  // Hold a strong reference to mGeckoMenu while calling its methods.
+  RefPtr<nsMenuX> geckoMenu = mGeckoMenu;
+  geckoMenu->OnWillActivateItem(aItem);
+}
+
+@end
+
+// OS X Leopard (at least as of 10.5.2) has an obscure bug triggered by some
+// behavior that's present in Mozilla.org browsers but not (as best I can
+// tell) in Apple products like Safari.  (It's not yet clear exactly what this
+// behavior is.)
+//
+// The bug is that sometimes you crash on quit in nsMenuX::RemoveAll(), on a
+// call to [NSMenu removeItemAtIndex:].  The crash is caused by trying to
+// access a deleted NSMenuItem object (sometimes (perhaps always?) by trying
+// to send it a _setChangedFlags: message).  Though this object was deleted
+// some time ago, it remains registered as a potential target for a particular
+// key equivalent.  So when [NSMenu removeItemAtIndex:] removes the current
+// target for that same key equivalent, the OS tries to "activate" the
+// previous target.
+//
+// The underlying reason appears to be that NSMenu's _addItem:toTable: and
+// _removeItem:fromTable: methods (which are used to keep a hashtable of
+// registered key equivalents) don't properly "retain" and "release"
+// NSMenuItem objects as they are added to and removed from the hashtable.
+//
+// Our (hackish) workaround is to shadow the OS's hashtable with another
+// hastable of our own (gShadowKeyEquivDB), and use it to "retain" and
+// "release" NSMenuItem objects as needed.  This resolves bmo bugs 422287 and
+// 423669.  When (if) Apple fixes this bug, we can remove this workaround.
+
+static NSMutableDictionary* gShadowKeyEquivDB = nil;
+
+// Class for values in gShadowKeyEquivDB.
+
+@interface KeyEquivDBItem : NSObject {
+  NSMenuItem* mItem;
+  NSMutableSet* mTables;
+}
+
+- (id)initWithItem:(NSMenuItem*)aItem table:(NSMapTable*)aTable;
+- (BOOL)hasTable:(NSMapTable*)aTable;
+- (int)addTable:(NSMapTable*)aTable;
+- (int)removeTable:(NSMapTable*)aTable;
+
+@end
+
+@implementation KeyEquivDBItem
+
+- (id)initWithItem:(NSMenuItem*)aItem table:(NSMapTable*)aTable {
+  if (!gShadowKeyEquivDB) {
+    gShadowKeyEquivDB = [[NSMutableDictionary alloc] init];
+  }
+  self = [super init];
+  if (aItem && aTable) {
+    mTables = [[NSMutableSet alloc] init];
+    mItem = [aItem retain];
+    [mTables addObject:[NSValue valueWithPointer:aTable]];
+  } else {
+    mTables = nil;
+    mItem = nil;
+  }
+  return self;
+}
+
+- (void)dealloc {
+  if (mTables) {
+    [mTables release];
+  }
+  if (mItem) {
+    [mItem release];
+  }
+  [super dealloc];
+}
+
+- (BOOL)hasTable:(NSMapTable*)aTable {
+  return [mTables member:[NSValue valueWithPointer:aTable]] ? YES : NO;
+}
+
+// Does nothing if aTable (its index value) is already present in mTables.
+- (int)addTable:(NSMapTable*)aTable {
+  if (aTable) {
+    [mTables addObject:[NSValue valueWithPointer:aTable]];
+  }
+  return [mTables count];
+}
+
+- (int)removeTable:(NSMapTable*)aTable {
+  if (aTable) {
+    NSValue* objectToRemove =
+        [mTables member:[NSValue valueWithPointer:aTable]];
+    if (objectToRemove) {
+      [mTables removeObject:objectToRemove];
+    }
+  }
+  return [mTables count];
+}
+
+@end
+
+@interface NSMenu (MethodSwizzling)
++ (void)nsMenuX_NSMenu_addItem:(NSMenuItem*)aItem toTable:(NSMapTable*)aTable;
++ (void)nsMenuX_NSMenu_removeItem:(NSMenuItem*)aItem
+                        fromTable:(NSMapTable*)aTable;
+@end
+
+@implementation NSMenu (MethodSwizzling)
+
++ (void)nsMenuX_NSMenu_addItem:(NSMenuItem*)aItem toTable:(NSMapTable*)aTable {
+  if (aItem && aTable) {
+    NSValue* key = [NSValue valueWithPointer:aItem];
+    KeyEquivDBItem* shadowItem = [gShadowKeyEquivDB objectForKey:key];
+    if (shadowItem) {
+      [shadowItem addTable:aTable];
+    } else {
+      shadowItem = [[KeyEquivDBItem alloc] initWithItem:aItem table:aTable];
+      [gShadowKeyEquivDB setObject:shadowItem forKey:key];
+      // Release after [NSMutableDictionary setObject:forKey:] retains it (so
+      // that it will get dealloced when removeObjectForKey: is called).
+      [shadowItem release];
+    }
+  }
+
+  [self nsMenuX_NSMenu_addItem:aItem toTable:aTable];
+}
+
++ (void)nsMenuX_NSMenu_removeItem:(NSMenuItem*)aItem
+                        fromTable:(NSMapTable*)aTable {
+  [self nsMenuX_NSMenu_removeItem:aItem fromTable:aTable];
+
+  if (aItem && aTable) {
+    NSValue* key = [NSValue valueWithPointer:aItem];
+    KeyEquivDBItem* shadowItem = [gShadowKeyEquivDB objectForKey:key];
+    if (shadowItem && [shadowItem hasTable:aTable]) {
+      if (![shadowItem removeTable:aTable]) {
+        [gShadowKeyEquivDB removeObjectForKey:key];
+      }
+    }
+  }
+}
+
+@end
+
+// This class is needed to keep track of when the OS is (re)indexing all of
+// our menus.  This appears to only happen on Leopard and higher, and can
+// be triggered by opening the Help menu.  Some operations are unsafe while
+// this is happening -- notably the calls to [[NSImage alloc]
+// initWithSize:imageRect.size] and [newImage lockFocus] in nsMenuItemIconX::
+// OnStopFrame().  But we don't yet have a complete list, and Apple doesn't
+// yet have any documentation on this subject.  (Apple also doesn't yet have
+// any documented way to find the information we seek here.)  The "original"
+// of this class (the one whose indexMenuBarDynamically method we hook) is
+// defined in the Shortcut framework in /System/Library/PrivateFrameworks.
+@interface NSObject (SCTGRLIndexMethodSwizzling)
+- (void)nsMenuX_SCTGRLIndex_indexMenuBarDynamically;
+@end
+
+@implementation NSObject (SCTGRLIndexMethodSwizzling)
+
+- (void)nsMenuX_SCTGRLIndex_indexMenuBarDynamically {
+  // This method appears to be called (once) whenever the OS (re)indexes our
+  // menus.  sIndexingMenuLevel is a int32_t just in case it might be
+  // reentered.  As it's running, it spawns calls to two undocumented
+  // HIToolbox methods (_SimulateMenuOpening() and _SimulateMenuClosed()),
+  // which "simulate" the opening and closing of our menus without actually
+  // displaying them.
+  ++nsMenuX::sIndexingMenuLevel;
+  [self nsMenuX_SCTGRLIndex_indexMenuBarDynamically];
+  --nsMenuX::sIndexingMenuLevel;
+}
+
+@end
+
+@interface NSObject (NSServicesMenuUpdaterSwizzling)
+- (void)nsMenuX_populateMenu:(NSMenu*)aMenu
+          withServiceEntries:(NSArray*)aServices
+                  forDisplay:(BOOL)aForDisplay;
+@end
+
+@interface _NSServiceEntry : NSObject
+- (NSString*)bundleIdentifier;
+@end
+
+@implementation NSObject (NSServicesMenuUpdaterSwizzling)
+
+- (void)nsMenuX_populateMenu:(NSMenu*)aMenu
+          withServiceEntries:(NSArray*)aServices
+                  forDisplay:(BOOL)aForDisplay {
+  NSMutableArray* filteredServices = [NSMutableArray array];
+
+  // We need to filter some services, such as "Search with Google", since this
+  // service is duplicating functionality already exposed by our "Search Google
+  // for..." context menu entry and because it opens in Safari, which can cause
+  // confusion for users.
+  for (_NSServiceEntry* service in aServices) {
+    NSString* bundleId = [service bundleIdentifier];
+    NSString* msg = [service valueForKey:@"message"];
+    bool shouldSkip = ([bundleId isEqualToString:@"com.apple.Safari"]) ||
+                      ([bundleId isEqualToString:@"com.apple.systemuiserver"] &&
+                       [msg isEqualToString:@"openURL"]);
+    if (!shouldSkip) {
+      [filteredServices addObject:service];
+    }
+  }
+
+  [self nsMenuX_populateMenu:aMenu
+          withServiceEntries:filteredServices
+                  forDisplay:aForDisplay];
+}
+
+@end
diff --git a/widget/cocoa/nsNativeThemeCocoa.h b/widget/cocoa/nsNativeThemeCocoa.h
new file mode 100644
index 0000000000..9488e50e1e
--- /dev/null
+++ b/widget/cocoa/nsNativeThemeCocoa.h
@@ -0,0 +1,408 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsNativeThemeCocoa_h_
+#define nsNativeThemeCocoa_h_
+
+#import <Carbon/Carbon.h>
+#import <Cocoa/Cocoa.h>
+
+#include "mozilla/Variant.h"
+
+#include "nsITheme.h"
+#include "ThemeCocoa.h"
+#include "mozilla/dom/RustTypes.h"
+
+@class MOZCellDrawWindow;
+@class MOZCellDrawView;
+@class MOZSearchFieldCell;
+@class NSProgressBarCell;
+class nsDeviceContext;
+struct SegmentedControlRenderSettings;
+
+namespace mozilla {
+namespace gfx {
+class DrawTarget;
+}  // namespace gfx
+}  // namespace mozilla
+
+class nsNativeThemeCocoa : public mozilla::widget::ThemeCocoa {
+  using ThemeCocoa = mozilla::widget::ThemeCocoa;
+
+ public:
+  enum class CheckboxOrRadioState : uint8_t { eOff, eOn, eIndeterminate };
+
+  enum class ButtonType : uint8_t {
+    eRegularPushButton,
+    eDefaultPushButton,
+    eSquareBezelPushButton,
+    eArrowButton,
+    eHelpButton,
+    eTreeTwistyPointingRight,
+    eTreeTwistyPointingDown,
+    eDisclosureButtonClosed,
+    eDisclosureButtonOpen
+  };
+
+  enum class SpinButton : uint8_t { eUp, eDown };
+
+  enum class SegmentType : uint8_t { eToolbarButton, eTab };
+
+  enum class OptimumState : uint8_t { eOptimum, eSubOptimum, eSubSubOptimum };
+
+  struct ControlParams {
+    ControlParams()
+        : disabled(false),
+          insideActiveWindow(false),
+          pressed(false),
+          focused(false),
+          rtl(false) {}
+
+    bool disabled : 1;
+    bool insideActiveWindow : 1;
+    bool pressed : 1;
+    bool focused : 1;
+    bool rtl : 1;
+  };
+
+  struct CheckboxOrRadioParams {
+    ControlParams controlParams;
+    CheckboxOrRadioState state = CheckboxOrRadioState::eOff;
+    float verticalAlignFactor = 0.5f;
+  };
+
+  struct ButtonParams {
+    ControlParams controlParams;
+    ButtonType button = ButtonType::eRegularPushButton;
+  };
+
+  struct DropdownParams {
+    ControlParams controlParams;
+    bool pullsDown = false;
+    bool editable = false;
+  };
+
+  struct SpinButtonParams {
+    mozilla::Maybe<SpinButton> pressedButton;
+    bool disabled = false;
+    bool insideActiveWindow = false;
+  };
+
+  struct SegmentParams {
+    SegmentType segmentType = SegmentType::eToolbarButton;
+    bool insideActiveWindow = false;
+    bool pressed = false;
+    bool selected = false;
+    bool focused = false;
+    bool atLeftEnd = false;
+    bool atRightEnd = false;
+    bool drawsLeftSeparator = false;
+    bool drawsRightSeparator = false;
+    bool rtl = false;
+  };
+
+  struct TextFieldParams {
+    float verticalAlignFactor = 0.5f;
+    bool insideToolbar = false;
+    bool disabled = false;
+    bool focused = false;
+    bool rtl = false;
+  };
+
+  struct ProgressParams {
+    double value = 0.0;
+    double max = 0.0;
+    float verticalAlignFactor = 0.5f;
+    bool insideActiveWindow = false;
+    bool indeterminate = false;
+    bool horizontal = false;
+    bool rtl = false;
+  };
+
+  struct MeterParams {
+    double value = 0;
+    double min = 0;
+    double max = 0;
+    OptimumState optimumState = OptimumState::eOptimum;
+    float verticalAlignFactor = 0.5f;
+    bool horizontal = true;
+    bool rtl = false;
+  };
+
+  struct TreeHeaderCellParams {
+    ControlParams controlParams;
+    TreeSortDirection sortDirection = eTreeSortDirection_Natural;
+    bool lastTreeHeaderCell = false;
+  };
+
+  struct ScaleParams {
+    int32_t value = 0;
+    int32_t min = 0;
+    int32_t max = 0;
+    bool insideActiveWindow = false;
+    bool disabled = false;
+    bool focused = false;
+    bool horizontal = true;
+    bool reverse = false;
+  };
+
+  enum Widget : uint8_t {
+    eColorFill,       // mozilla::gfx::sRGBColor
+    eCheckbox,        // CheckboxOrRadioParams
+    eRadio,           // CheckboxOrRadioParams
+    eButton,          // ButtonParams
+    eDropdown,        // DropdownParams
+    eSpinButtons,     // SpinButtonParams
+    eSpinButtonUp,    // SpinButtonParams
+    eSpinButtonDown,  // SpinButtonParams
+    eSegment,         // SegmentParams
+    eSeparator,
+    eToolbar,    // bool
+    eStatusBar,  // bool
+    eGroupBox,
+    eTextField,           // TextFieldParams
+    eSearchField,         // TextFieldParams
+    eProgressBar,         // ProgressParams
+    eMeter,               // MeterParams
+    eTreeHeaderCell,      // TreeHeaderCellParams
+    eScale,               // ScaleParams
+    eMultilineTextField,  // bool
+    eListBox,
+    eTabPanel,
+  };
+
+  struct WidgetInfo {
+    static WidgetInfo ColorFill(const mozilla::gfx::sRGBColor& aParams) {
+      return WidgetInfo(Widget::eColorFill, aParams);
+    }
+    static WidgetInfo Checkbox(const CheckboxOrRadioParams& aParams) {
+      return WidgetInfo(Widget::eCheckbox, aParams);
+    }
+    static WidgetInfo Radio(const CheckboxOrRadioParams& aParams) {
+      return WidgetInfo(Widget::eRadio, aParams);
+    }
+    static WidgetInfo Button(const ButtonParams& aParams) {
+      return WidgetInfo(Widget::eButton, aParams);
+    }
+    static WidgetInfo Dropdown(const DropdownParams& aParams) {
+      return WidgetInfo(Widget::eDropdown, aParams);
+    }
+    static WidgetInfo SpinButtons(const SpinButtonParams& aParams) {
+      return WidgetInfo(Widget::eSpinButtons, aParams);
+    }
+    static WidgetInfo SpinButtonUp(const SpinButtonParams& aParams) {
+      return WidgetInfo(Widget::eSpinButtonUp, aParams);
+    }
+    static WidgetInfo SpinButtonDown(const SpinButtonParams& aParams) {
+      return WidgetInfo(Widget::eSpinButtonDown, aParams);
+    }
+    static WidgetInfo Segment(const SegmentParams& aParams) {
+      return WidgetInfo(Widget::eSegment, aParams);
+    }
+    static WidgetInfo Separator() {
+      return WidgetInfo(Widget::eSeparator, false);
+    }
+    static WidgetInfo Toolbar(bool aParams) {
+      return WidgetInfo(Widget::eToolbar, aParams);
+    }
+    static WidgetInfo StatusBar(bool aParams) {
+      return WidgetInfo(Widget::eStatusBar, aParams);
+    }
+    static WidgetInfo GroupBox() {
+      return WidgetInfo(Widget::eGroupBox, false);
+    }
+    static WidgetInfo TextField(const TextFieldParams& aParams) {
+      return WidgetInfo(Widget::eTextField, aParams);
+    }
+    static WidgetInfo SearchField(const TextFieldParams& aParams) {
+      return WidgetInfo(Widget::eSearchField, aParams);
+    }
+    static WidgetInfo ProgressBar(const ProgressParams& aParams) {
+      return WidgetInfo(Widget::eProgressBar, aParams);
+    }
+    static WidgetInfo Meter(const MeterParams& aParams) {
+      return WidgetInfo(Widget::eMeter, aParams);
+    }
+    static WidgetInfo TreeHeaderCell(const TreeHeaderCellParams& aParams) {
+      return WidgetInfo(Widget::eTreeHeaderCell, aParams);
+    }
+    static WidgetInfo Scale(const ScaleParams& aParams) {
+      return WidgetInfo(Widget::eScale, aParams);
+    }
+    static WidgetInfo MultilineTextField(bool aParams) {
+      return WidgetInfo(Widget::eMultilineTextField, aParams);
+    }
+    static WidgetInfo ListBox() { return WidgetInfo(Widget::eListBox, false); }
+    static WidgetInfo TabPanel(bool aParams) {
+      return WidgetInfo(Widget::eTabPanel, aParams);
+    }
+
+    template <typename T>
+    T Params() const {
+      MOZ_RELEASE_ASSERT(mVariant.is<T>());
+      return mVariant.as<T>();
+    }
+
+    enum Widget Widget() const { return mWidget; }
+
+   private:
+    template <typename T>
+    WidgetInfo(enum Widget aWidget, const T& aParams)
+        : mVariant(aParams), mWidget(aWidget) {}
+
+    mozilla::Variant<mozilla::gfx::sRGBColor, CheckboxOrRadioParams,
+                     ButtonParams, DropdownParams, SpinButtonParams,
+                     SegmentParams, TextFieldParams, ProgressParams,
+                     MeterParams, TreeHeaderCellParams, ScaleParams, bool>
+        mVariant;
+
+    enum Widget mWidget;
+  };
+
+  explicit nsNativeThemeCocoa();
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // The nsITheme interface.
+  NS_IMETHOD DrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
+                                  StyleAppearance aAppearance,
+                                  const nsRect& aRect, const nsRect& aDirtyRect,
+                                  DrawOverflow) override;
+  bool CreateWebRenderCommandsForWidget(
+      mozilla::wr::DisplayListBuilder& aBuilder,
+      mozilla::wr::IpcResourceUpdateQueue& aResources,
+      const mozilla::layers::StackingContextHelper& aSc,
+      mozilla::layers::RenderRootStateManager* aManager, nsIFrame* aFrame,
+      StyleAppearance aAppearance, const nsRect& aRect) override;
+  [[nodiscard]] LayoutDeviceIntMargin GetWidgetBorder(
+      nsDeviceContext* aContext, nsIFrame* aFrame,
+      StyleAppearance aAppearance) override;
+
+  bool GetWidgetPadding(nsDeviceContext* aContext, nsIFrame* aFrame,
+                        StyleAppearance aAppearance,
+                        LayoutDeviceIntMargin* aResult) override;
+
+  virtual bool GetWidgetOverflow(nsDeviceContext* aContext, nsIFrame* aFrame,
+                                 StyleAppearance aAppearance,
+                                 nsRect* aOverflowRect) override;
+
+  LayoutDeviceIntSize GetMinimumWidgetSize(nsPresContext*, nsIFrame*,
+                                           StyleAppearance) override;
+  NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, StyleAppearance aAppearance,
+                                nsAtom* aAttribute, bool* aShouldRepaint,
+                                const nsAttrValue* aOldValue) override;
+  NS_IMETHOD ThemeChanged() override;
+  bool ThemeSupportsWidget(nsPresContext* aPresContext, nsIFrame* aFrame,
+                           StyleAppearance aAppearance) override;
+  bool WidgetIsContainer(StyleAppearance aAppearance) override;
+  bool ThemeDrawsFocusForWidget(nsIFrame*, StyleAppearance) override;
+  bool ThemeNeedsComboboxDropmarker() override;
+  virtual bool WidgetAppearanceDependsOnWindowFocus(
+      StyleAppearance aAppearance) override;
+  virtual ThemeGeometryType ThemeGeometryTypeForWidget(
+      nsIFrame* aFrame, StyleAppearance aAppearance) override;
+  virtual Transparency GetWidgetTransparency(
+      nsIFrame* aFrame, StyleAppearance aAppearance) override;
+  mozilla::Maybe<WidgetInfo> ComputeWidgetInfo(nsIFrame* aFrame,
+                                               StyleAppearance aAppearance,
+                                               const nsRect& aRect);
+  void DrawProgress(CGContextRef context, const HIRect& inBoxRect,
+                    const ProgressParams& aParams);
+
+ protected:
+  virtual ~nsNativeThemeCocoa();
+
+  LayoutDeviceIntMargin DirectionAwareMargin(
+      const LayoutDeviceIntMargin& aMargin, nsIFrame* aFrame);
+  nsIFrame* SeparatorResponsibility(nsIFrame* aBefore, nsIFrame* aAfter);
+  ControlParams ComputeControlParams(nsIFrame* aFrame,
+                                     mozilla::dom::ElementState aEventState);
+  SegmentParams ComputeSegmentParams(nsIFrame* aFrame,
+                                     mozilla::dom::ElementState aEventState,
+                                     SegmentType aSegmentType);
+  TextFieldParams ComputeTextFieldParams(
+      nsIFrame* aFrame, mozilla::dom::ElementState aEventState);
+  ProgressParams ComputeProgressParams(nsIFrame* aFrame,
+                                       mozilla::dom::ElementState aEventState,
+                                       bool aIsHorizontal);
+  MeterParams ComputeMeterParams(nsIFrame* aFrame);
+  TreeHeaderCellParams ComputeTreeHeaderCellParams(
+      nsIFrame* aFrame, mozilla::dom::ElementState aEventState);
+  mozilla::Maybe<ScaleParams> ComputeHTMLScaleParams(
+      nsIFrame* aFrame, mozilla::dom::ElementState aEventState);
+
+  // HITheme drawing routines
+  void DrawMeter(CGContextRef context, const HIRect& inBoxRect,
+                 const MeterParams& aParams);
+  void DrawSegment(CGContextRef cgContext, const HIRect& inBoxRect,
+                   const SegmentParams& aParams);
+  void DrawSegmentBackground(CGContextRef cgContext, const HIRect& inBoxRect,
+                             const SegmentParams& aParams);
+  void DrawTabPanel(CGContextRef context, const HIRect& inBoxRect,
+                    bool aIsInsideActiveWindow);
+  void DrawScale(CGContextRef context, const HIRect& inBoxRect,
+                 const ScaleParams& aParams);
+  void DrawCheckboxOrRadio(CGContextRef cgContext, bool inCheckbox,
+                           const HIRect& inBoxRect,
+                           const CheckboxOrRadioParams& aParams);
+  void DrawSearchField(CGContextRef cgContext, const HIRect& inBoxRect,
+                       const TextFieldParams& aParams);
+  void DrawTextField(CGContextRef cgContext, const HIRect& inBoxRect,
+                     const TextFieldParams& aParams);
+  void DrawPushButton(CGContextRef cgContext, const HIRect& inBoxRect,
+                      ButtonType aButtonType, ControlParams aControlParams);
+  void DrawSquareBezelPushButton(CGContextRef cgContext,
+                                 const HIRect& inBoxRect,
+                                 ControlParams aControlParams);
+  void DrawHelpButton(CGContextRef cgContext, const HIRect& inBoxRect,
+                      ControlParams aControlParams);
+  void DrawDisclosureButton(CGContextRef cgContext, const HIRect& inBoxRect,
+                            ControlParams aControlParams,
+                            NSControlStateValue aState);
+  void DrawHIThemeButton(CGContextRef cgContext, const HIRect& aRect,
+                         ThemeButtonKind aKind, ThemeButtonValue aValue,
+                         ThemeDrawState aState, ThemeButtonAdornment aAdornment,
+                         const ControlParams& aParams);
+  void DrawButton(CGContextRef context, const HIRect& inBoxRect,
+                  const ButtonParams& aParams);
+  void DrawTreeHeaderCell(CGContextRef context, const HIRect& inBoxRect,
+                          const TreeHeaderCellParams& aParams);
+  void DrawDropdown(CGContextRef context, const HIRect& inBoxRect,
+                    const DropdownParams& aParams);
+  HIThemeButtonDrawInfo SpinButtonDrawInfo(ThemeButtonKind aKind,
+                                           const SpinButtonParams& aParams);
+  void DrawSpinButtons(CGContextRef context, const HIRect& inBoxRect,
+                       const SpinButtonParams& aParams);
+  void DrawSpinButton(CGContextRef context, const HIRect& inBoxRect,
+                      SpinButton aDrawnButton, const SpinButtonParams& aParams);
+  void DrawToolbar(CGContextRef cgContext, const CGRect& inBoxRect,
+                   bool aIsMain);
+  void DrawStatusBar(CGContextRef cgContext, const HIRect& inBoxRect,
+                     bool aIsMain);
+  void DrawMultilineTextField(CGContextRef cgContext, const CGRect& inBoxRect,
+                              bool aIsFocused);
+  void RenderWidget(const WidgetInfo& aWidgetInfo, mozilla::ColorScheme,
+                    mozilla::gfx::DrawTarget& aDrawTarget,
+                    const mozilla::gfx::Rect& aWidgetRect,
+                    const mozilla::gfx::Rect& aDirtyRect, float aScale);
+
+ private:
+  NSButtonCell* mDisclosureButtonCell;
+  NSButtonCell* mHelpButtonCell;
+  NSButtonCell* mPushButtonCell;
+  NSButtonCell* mRadioButtonCell;
+  NSButtonCell* mCheckboxCell;
+  NSTextFieldCell* mTextFieldCell;
+  MOZSearchFieldCell* mSearchFieldCell;
+  NSPopUpButtonCell* mDropdownCell;
+  NSComboBoxCell* mComboBoxCell;
+  NSProgressBarCell* mProgressBarCell;
+  NSLevelIndicatorCell* mMeterBarCell;
+  NSTableHeaderCell* mTreeHeaderCell;
+  MOZCellDrawWindow* mCellDrawWindow = nil;
+  MOZCellDrawView* mCellDrawView;
+};
+
+#endif  // nsNativeThemeCocoa_h_
diff --git a/widget/cocoa/nsNativeThemeCocoa.mm b/widget/cocoa/nsNativeThemeCocoa.mm
new file mode 100644
index 0000000000..ff715ac57c
--- /dev/null
+++ b/widget/cocoa/nsNativeThemeCocoa.mm
@@ -0,0 +1,3328 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsNativeThemeCocoa.h"
+#include <objc/NSObjCRuntime.h>
+
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Helpers.h"
+#include "mozilla/gfx/PathHelpers.h"
+#include "nsChildView.h"
+#include "nsDeviceContext.h"
+#include "nsLayoutUtils.h"
+#include "nsObjCExceptions.h"
+#include "nsNumberControlFrame.h"
+#include "nsRangeFrame.h"
+#include "nsRect.h"
+#include "nsSize.h"
+#include "nsStyleConsts.h"
+#include "nsPresContext.h"
+#include "nsIContent.h"
+#include "mozilla/dom/Document.h"
+#include "nsIFrame.h"
+#include "nsAtom.h"
+#include "nsNameSpaceManager.h"
+#include "nsPresContext.h"
+#include "nsGkAtoms.h"
+#include "nsCocoaFeatures.h"
+#include "nsCocoaWindow.h"
+#include "nsNativeThemeColors.h"
+#include "nsIScrollableFrame.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Range.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/HTMLMeterElement.h"
+#include "mozilla/layers/StackingContextHelper.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsLookAndFeel.h"
+#include "MacThemeGeometryType.h"
+#include "VibrancyManager.h"
+
+#include "gfxContext.h"
+#include "gfxQuartzSurface.h"
+#include "gfxQuartzNativeDrawing.h"
+#include "gfxUtils.h"  // for ToDeviceColor
+#include <algorithm>
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using mozilla::dom::HTMLMeterElement;
+
+#define DRAW_IN_FRAME_DEBUG 0
+#define SCROLLBARS_VISUAL_DEBUG 0
+
+// private Quartz routines needed here
+extern "C" {
+CG_EXTERN void CGContextSetCTM(CGContextRef, CGAffineTransform);
+CG_EXTERN void CGContextSetBaseCTM(CGContextRef, CGAffineTransform);
+typedef CFTypeRef CUIRendererRef;
+void CUIDraw(CUIRendererRef r, CGRect rect, CGContextRef ctx,
+             CFDictionaryRef options, CFDictionaryRef* result);
+}
+
+// Workaround for NSCell control tint drawing
+// Without this workaround, NSCells are always drawn with the clear control tint
+// as long as they're not attached to an NSControl which is a subview of an
+// active window.
+// XXXmstange Why doesn't Webkit need this?
+@implementation NSCell (ControlTintWorkaround)
+- (int)_realControlTint {
+  return [self controlTint];
+}
+@end
+
+// This is the window for our MOZCellDrawView. When an NSCell is drawn, some
+// NSCell implementations look at the draw view's window to determine whether
+// the cell should draw with the active look.
+@interface MOZCellDrawWindow : NSWindow
+@property BOOL cellsShouldLookActive;
+@end
+
+@implementation MOZCellDrawWindow
+
+// Override three different methods, for good measure. The NSCell implementation
+// could call any one of them.
+- (BOOL)_hasActiveAppearance {
+  return self.cellsShouldLookActive;
+}
+- (BOOL)hasKeyAppearance {
+  return self.cellsShouldLookActive;
+}
+- (BOOL)_hasKeyAppearance {
+  return self.cellsShouldLookActive;
+}
+
+@end
+
+// The purpose of this class is to provide objects that can be used when drawing
+// NSCells using drawWithFrame:inView: without causing any harm. Only a small
+// number of methods are called on the draw view, among those "isFlipped" and
+// "currentEditor": isFlipped needs to return YES in order to avoid drawing bugs
+// on 10.4 (see bug 465069); currentEditor (which isn't even a method of
+// NSView) will be called when drawing search fields, and we only provide it in
+// order to prevent "unrecognized selector" exceptions.
+// There's no need to pass the actual NSView that we're drawing into to
+// drawWithFrame:inView:. What's more, doing so even causes unnecessary
+// invalidations as soon as we draw a focusring!
+// This class needs to be an NSControl so that NSTextFieldCell (and
+// NSSearchFieldCell, which is a subclass of NSTextFieldCell) draws a focus
+// ring.
+@interface MOZCellDrawView : NSControl
+// Called by NSTreeHeaderCell during drawing.
+@property BOOL _drawingEndSeparator;
+@end
+
+@implementation MOZCellDrawView
+
+- (BOOL)isFlipped {
+  return YES;
+}
+
+- (NSText*)currentEditor {
+  return nil;
+}
+
+@end
+
+static void DrawFocusRingForCellIfNeeded(NSCell* aCell, NSRect aWithFrame,
+                                         NSView* aInView) {
+  if ([aCell showsFirstResponder]) {
+    CGContextRef cgContext = [[NSGraphicsContext currentContext] CGContext];
+    CGContextSaveGState(cgContext);
+
+    // It's important to set the focus ring style before we enter the
+    // transparency layer so that the transparency layer only contains
+    // the normal button mask without the focus ring, and the conversion
+    // to the focus ring shape happens only when the transparency layer is
+    // ended.
+    NSSetFocusRingStyle(NSFocusRingOnly);
+
+    // We need to draw the whole button into a transparency layer because
+    // many button types are composed of multiple parts, and if these parts
+    // were drawn while the focus ring style was active, each individual part
+    // would produce a focus ring for itself. But we only want one focus ring
+    // for the whole button. The transparency layer is a way to merge the
+    // individual button parts together before the focus ring shape is
+    // calculated.
+    CGContextBeginTransparencyLayerWithRect(cgContext,
+                                            NSRectToCGRect(aWithFrame), 0);
+    [aCell drawFocusRingMaskWithFrame:aWithFrame inView:aInView];
+    CGContextEndTransparencyLayer(cgContext);
+
+    CGContextRestoreGState(cgContext);
+  }
+}
+
+static void DrawCellIncludingFocusRing(NSCell* aCell, NSRect aWithFrame,
+                                       NSView* aInView) {
+  [aCell drawWithFrame:aWithFrame inView:aInView];
+  DrawFocusRingForCellIfNeeded(aCell, aWithFrame, aInView);
+}
+
+/**
+ * NSProgressBarCell is used to draw progress bars of any size.
+ */
+@interface NSProgressBarCell : NSCell {
+  /*All instance variables are private*/
+  double mValue;
+  double mMax;
+  bool mIsIndeterminate;
+  bool mIsHorizontal;
+}
+
+- (void)setValue:(double)value;
+- (double)value;
+- (void)setMax:(double)max;
+- (double)max;
+- (void)setIndeterminate:(bool)aIndeterminate;
+- (bool)isIndeterminate;
+- (void)setHorizontal:(bool)aIsHorizontal;
+- (bool)isHorizontal;
+- (void)drawWithFrame:(NSRect)cellFrame inView:(NSView*)controlView;
+@end
+
+@implementation NSProgressBarCell
+
+- (void)setMax:(double)aMax {
+  mMax = aMax;
+}
+
+- (double)max {
+  return mMax;
+}
+
+- (void)setValue:(double)aValue {
+  mValue = aValue;
+}
+
+- (double)value {
+  return mValue;
+}
+
+- (void)setIndeterminate:(bool)aIndeterminate {
+  mIsIndeterminate = aIndeterminate;
+}
+
+- (bool)isIndeterminate {
+  return mIsIndeterminate;
+}
+
+- (void)setHorizontal:(bool)aIsHorizontal {
+  mIsHorizontal = aIsHorizontal;
+}
+
+- (bool)isHorizontal {
+  return mIsHorizontal;
+}
+
+- (void)drawWithFrame:(NSRect)cellFrame inView:(NSView*)controlView {
+  CGContext* cgContext = [[NSGraphicsContext currentContext] CGContext];
+
+  HIThemeTrackDrawInfo tdi;
+
+  tdi.version = 0;
+  tdi.min = 0;
+
+  tdi.value = INT32_MAX * (mValue / mMax);
+  tdi.max = INT32_MAX;
+  tdi.bounds = NSRectToCGRect(cellFrame);
+  tdi.attributes = mIsHorizontal ? kThemeTrackHorizontal : 0;
+  tdi.enableState = [self controlTint] == NSClearControlTint
+                        ? kThemeTrackInactive
+                        : kThemeTrackActive;
+
+  NSControlSize size = [self controlSize];
+  if (size == NSControlSizeRegular) {
+    tdi.kind =
+        mIsIndeterminate ? kThemeLargeIndeterminateBar : kThemeLargeProgressBar;
+  } else {
+    NS_ASSERTION(
+        size == NSControlSizeSmall,
+        "We shouldn't have another size than small and regular for the moment");
+    tdi.kind = mIsIndeterminate ? kThemeMediumIndeterminateBar
+                                : kThemeMediumProgressBar;
+  }
+
+  int32_t stepsPerSecond = mIsIndeterminate ? 60 : 30;
+  int32_t milliSecondsPerStep = 1000 / stepsPerSecond;
+  tdi.trackInfo.progress.phase = uint8_t(
+      PR_IntervalToMilliseconds(PR_IntervalNow()) / milliSecondsPerStep);
+
+  HIThemeDrawTrack(&tdi, NULL, cgContext, kHIThemeOrientationNormal);
+}
+
+@end
+
+@interface MOZSearchFieldCell : NSSearchFieldCell
+@property BOOL shouldUseToolbarStyle;
+@end
+
+@implementation MOZSearchFieldCell
+
+- (instancetype)init {
+  // We would like to render a search field which has the magnifying glass icon
+  // at the start of the search field, and no cancel button. On 10.12 and 10.13,
+  // empty search fields render the magnifying glass icon in the middle of the
+  // field. So in order to get the icon to show at the start of the field, we
+  // need to give the field some content. We achieve this with a single space
+  // character.
+  self = [super initTextCell:@" "];
+
+  // However, because the field is now non-empty, by default it shows a cancel
+  // button. To hide the cancel button, override it with a custom NSButtonCell
+  // which renders nothing.
+  NSButtonCell* invisibleCell = [[NSButtonCell alloc] initImageCell:nil];
+  invisibleCell.bezeled = NO;
+  invisibleCell.bordered = NO;
+  self.cancelButtonCell = invisibleCell;
+  [invisibleCell release];
+
+  return self;
+}
+
+- (BOOL)_isToolbarMode {
+  return self.shouldUseToolbarStyle;
+}
+
+@end
+
+#define HITHEME_ORIENTATION kHIThemeOrientationNormal
+
+static CGFloat kMaxFocusRingWidth =
+    0;  // initialized by the nsNativeThemeCocoa constructor
+
+// These enums are for indexing into the margin array.
+enum {
+  leopardOSorlater = 0,  // 10.6 - 10.9
+  yosemiteOSorlater = 1  // 10.10+
+};
+
+enum { miniControlSize, smallControlSize, regularControlSize };
+
+enum { leftMargin, topMargin, rightMargin, bottomMargin };
+
+static size_t EnumSizeForCocoaSize(NSControlSize cocoaControlSize) {
+  if (cocoaControlSize == NSControlSizeMini)
+    return miniControlSize;
+  else if (cocoaControlSize == NSControlSizeSmall)
+    return smallControlSize;
+  else
+    return regularControlSize;
+}
+
+static NSControlSize CocoaSizeForEnum(int32_t enumControlSize) {
+  if (enumControlSize == miniControlSize)
+    return NSControlSizeMini;
+  else if (enumControlSize == smallControlSize)
+    return NSControlSizeSmall;
+  else
+    return NSControlSizeRegular;
+}
+
+static NSString* CUIControlSizeForCocoaSize(NSControlSize aControlSize) {
+  if (aControlSize == NSControlSizeRegular)
+    return @"regular";
+  else if (aControlSize == NSControlSizeSmall)
+    return @"small";
+  else
+    return @"mini";
+}
+
+static void InflateControlRect(NSRect* rect, NSControlSize cocoaControlSize,
+                               const float marginSet[][3][4]) {
+  if (!marginSet) return;
+
+  static int osIndex = yosemiteOSorlater;
+  size_t controlSize = EnumSizeForCocoaSize(cocoaControlSize);
+  const float* buttonMargins = marginSet[osIndex][controlSize];
+  rect->origin.x -= buttonMargins[leftMargin];
+  rect->origin.y -= buttonMargins[bottomMargin];
+  rect->size.width += buttonMargins[leftMargin] + buttonMargins[rightMargin];
+  rect->size.height += buttonMargins[bottomMargin] + buttonMargins[topMargin];
+}
+
+static NSWindow* NativeWindowForFrame(nsIFrame* aFrame,
+                                      nsIWidget** aTopLevelWidget = NULL) {
+  if (!aFrame) return nil;
+
+  nsIWidget* widget = aFrame->GetNearestWidget();
+  if (!widget) return nil;
+
+  nsIWidget* topLevelWidget = widget->GetTopLevelWidget();
+  if (aTopLevelWidget) *aTopLevelWidget = topLevelWidget;
+
+  return (NSWindow*)topLevelWidget->GetNativeData(NS_NATIVE_WINDOW);
+}
+
+static NSSize WindowButtonsSize(nsIFrame* aFrame) {
+  NSWindow* window = NativeWindowForFrame(aFrame);
+  if (!window) {
+    // Return fallback values.
+    return NSMakeSize(54, 16);
+  }
+
+  NSRect buttonBox = NSZeroRect;
+  NSButton* closeButton = [window standardWindowButton:NSWindowCloseButton];
+  if (closeButton) {
+    buttonBox = NSUnionRect(buttonBox, [closeButton frame]);
+  }
+  NSButton* minimizeButton =
+      [window standardWindowButton:NSWindowMiniaturizeButton];
+  if (minimizeButton) {
+    buttonBox = NSUnionRect(buttonBox, [minimizeButton frame]);
+  }
+  NSButton* zoomButton = [window standardWindowButton:NSWindowZoomButton];
+  if (zoomButton) {
+    buttonBox = NSUnionRect(buttonBox, [zoomButton frame]);
+  }
+  return buttonBox.size;
+}
+
+static BOOL FrameIsInActiveWindow(nsIFrame* aFrame) {
+  nsIWidget* topLevelWidget = NULL;
+  NSWindow* win = NativeWindowForFrame(aFrame, &topLevelWidget);
+  if (!topLevelWidget || !win) return YES;
+
+  // XUL popups, e.g. the toolbar customization popup, can't become key windows,
+  // but controls in these windows should still get the active look.
+  if (topLevelWidget->GetWindowType() == widget::WindowType::Popup) {
+    return YES;
+  }
+  if ([win isSheet]) {
+    return [win isKeyWindow];
+  }
+  return [win isMainWindow] && ![win attachedSheet];
+}
+
+// Toolbar controls and content controls respond to different window
+// activeness states.
+static BOOL IsActive(nsIFrame* aFrame, BOOL aIsToolbarControl) {
+  if (aIsToolbarControl) return [NativeWindowForFrame(aFrame) isMainWindow];
+  return FrameIsInActiveWindow(aFrame);
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(nsNativeThemeCocoa, nsNativeTheme, nsITheme)
+
+nsNativeThemeCocoa::nsNativeThemeCocoa() : ThemeCocoa(ScrollbarStyle()) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  kMaxFocusRingWidth = 7;
+
+  // provide a local autorelease pool, as this is called during startup
+  // before the main event-loop pool is in place
+  nsAutoreleasePool pool;
+
+  mDisclosureButtonCell = [[NSButtonCell alloc] initTextCell:@""];
+  [mDisclosureButtonCell setBezelStyle:NSBezelStyleRoundedDisclosure];
+  [mDisclosureButtonCell setButtonType:NSButtonTypePushOnPushOff];
+  [mDisclosureButtonCell setHighlightsBy:NSPushInCellMask];
+
+  mHelpButtonCell = [[NSButtonCell alloc] initTextCell:@""];
+  [mHelpButtonCell setBezelStyle:NSBezelStyleHelpButton];
+  [mHelpButtonCell setButtonType:NSButtonTypeMomentaryPushIn];
+  [mHelpButtonCell setHighlightsBy:NSPushInCellMask];
+
+  mPushButtonCell = [[NSButtonCell alloc] initTextCell:@""];
+  [mPushButtonCell setButtonType:NSButtonTypeMomentaryPushIn];
+  [mPushButtonCell setHighlightsBy:NSPushInCellMask];
+
+  mRadioButtonCell = [[NSButtonCell alloc] initTextCell:@""];
+  [mRadioButtonCell setButtonType:NSButtonTypeRadio];
+
+  mCheckboxCell = [[NSButtonCell alloc] initTextCell:@""];
+  [mCheckboxCell setButtonType:NSButtonTypeSwitch];
+  [mCheckboxCell setAllowsMixedState:YES];
+
+  mTextFieldCell = [[NSTextFieldCell alloc] initTextCell:@""];
+  [mTextFieldCell setBezeled:YES];
+  [mTextFieldCell setEditable:YES];
+  [mTextFieldCell setFocusRingType:NSFocusRingTypeExterior];
+
+  mSearchFieldCell = [[MOZSearchFieldCell alloc] init];
+  [mSearchFieldCell setBezelStyle:NSTextFieldRoundedBezel];
+  [mSearchFieldCell setBezeled:YES];
+  [mSearchFieldCell setEditable:YES];
+  [mSearchFieldCell setFocusRingType:NSFocusRingTypeExterior];
+
+  mDropdownCell = [[NSPopUpButtonCell alloc] initTextCell:@"" pullsDown:NO];
+
+  mComboBoxCell = [[NSComboBoxCell alloc] initTextCell:@""];
+  [mComboBoxCell setBezeled:YES];
+  [mComboBoxCell setEditable:YES];
+  [mComboBoxCell setFocusRingType:NSFocusRingTypeExterior];
+
+  mProgressBarCell = [[NSProgressBarCell alloc] init];
+
+  mMeterBarCell = [[NSLevelIndicatorCell alloc]
+      initWithLevelIndicatorStyle:NSLevelIndicatorStyleContinuousCapacity];
+
+  mTreeHeaderCell = [[NSTableHeaderCell alloc] init];
+
+  mCellDrawView = [[MOZCellDrawView alloc] init];
+
+  if (XRE_IsParentProcess()) {
+    // Put the cell draw view into a window that is never shown.
+    // This allows us to convince some NSCell implementations (such as
+    // NSButtonCell for default buttons) to draw with the active appearance.
+    // Another benefit of putting the draw view in a window is the fact that it
+    // lets NSTextFieldCell (and its subclass NSSearchFieldCell) inherit the
+    // current NSApplication effectiveAppearance automatically, so the field
+    // adapts to Dark Mode correctly. We don't create this window when the
+    // native theme is used in the content process because NSWindow creation
+    // runs into the sandbox and because we never run default buttons in content
+    // processes anyway.
+    mCellDrawWindow = [[MOZCellDrawWindow alloc]
+        initWithContentRect:NSZeroRect
+                  styleMask:NSWindowStyleMaskBorderless
+                    backing:NSBackingStoreBuffered
+                      defer:NO];
+    [mCellDrawWindow.contentView addSubview:mCellDrawView];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+nsNativeThemeCocoa::~nsNativeThemeCocoa() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [mMeterBarCell release];
+  [mProgressBarCell release];
+  [mDisclosureButtonCell release];
+  [mHelpButtonCell release];
+  [mPushButtonCell release];
+  [mRadioButtonCell release];
+  [mCheckboxCell release];
+  [mTextFieldCell release];
+  [mSearchFieldCell release];
+  [mDropdownCell release];
+  [mComboBoxCell release];
+  [mTreeHeaderCell release];
+  [mCellDrawWindow release];
+  [mCellDrawView release];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Limit on the area of the target rect (in pixels^2) in
+// DrawCellWithScaling() and DrawButton() and above which we
+// don't draw the object into a bitmap buffer.  This is to avoid crashes in
+// [NSGraphicsContext graphicsContextWithCGContext:flipped:] and
+// CGContextDrawImage(), and also to avoid very poor drawing performance in
+// CGContextDrawImage() when it scales the bitmap (particularly if xscale or
+// yscale is less than but near 1 -- e.g. 0.9).  This value was determined
+// by trial and error, on OS X 10.4.11 and 10.5.4, and on systems with
+// different amounts of RAM.
+#define BITMAP_MAX_AREA 500000
+
+static int GetBackingScaleFactorForRendering(CGContextRef cgContext) {
+  CGAffineTransform ctm =
+      CGContextGetUserSpaceToDeviceSpaceTransform(cgContext);
+  CGRect transformedUserSpacePixel =
+      CGRectApplyAffineTransform(CGRectMake(0, 0, 1, 1), ctm);
+  float maxScale = std::max(fabs(transformedUserSpacePixel.size.width),
+                            fabs(transformedUserSpacePixel.size.height));
+  return maxScale > 1.0 ? 2 : 1;
+}
+
+/*
+ * Draw the given NSCell into the given cgContext.
+ *
+ * destRect - the size and position of the resulting control rectangle
+ * controlSize - the NSControlSize which will be given to the NSCell before
+ *  asking it to render
+ * naturalSize - The natural dimensions of this control.
+ *  If the control rect size is not equal to either of these, a scale
+ *  will be applied to the context so that rendering the control at the
+ *  natural size will result in it filling the destRect space.
+ *  If a control has no natural dimensions in either/both axes, pass 0.0f.
+ * minimumSize - The minimum dimensions of this control.
+ *  If the control rect size is less than the minimum for a given axis,
+ *  a scale will be applied to the context so that the minimum is used
+ *  for drawing.  If a control has no minimum dimensions in either/both
+ *  axes, pass 0.0f.
+ * marginSet - an array of margins; a multidimensional array of [2][3][4],
+ *  with the first dimension being the OS version (Tiger or Leopard),
+ *  the second being the control size (mini, small, regular), and the third
+ *  being the 4 margin values (left, top, right, bottom).
+ * view - The NSView that we're drawing into. As far as I can tell, it doesn't
+ *  matter if this is really the right view; it just has to return YES when
+ *  asked for isFlipped. Otherwise we'll get drawing bugs on 10.4.
+ * mirrorHorizontal - whether to mirror the cell horizontally
+ */
+static void DrawCellWithScaling(NSCell* cell, CGContextRef cgContext,
+                                const HIRect& destRect,
+                                NSControlSize controlSize, NSSize naturalSize,
+                                NSSize minimumSize,
+                                const float marginSet[][3][4], NSView* view,
+                                BOOL mirrorHorizontal) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NSRect drawRect = NSMakeRect(destRect.origin.x, destRect.origin.y,
+                               destRect.size.width, destRect.size.height);
+
+  if (naturalSize.width != 0.0f) drawRect.size.width = naturalSize.width;
+  if (naturalSize.height != 0.0f) drawRect.size.height = naturalSize.height;
+
+  // Keep aspect ratio when scaling if one dimension is free.
+  if (naturalSize.width == 0.0f && naturalSize.height != 0.0f)
+    drawRect.size.width =
+        destRect.size.width * naturalSize.height / destRect.size.height;
+  if (naturalSize.height == 0.0f && naturalSize.width != 0.0f)
+    drawRect.size.height =
+        destRect.size.height * naturalSize.width / destRect.size.width;
+
+  // Honor minimum sizes.
+  if (drawRect.size.width < minimumSize.width)
+    drawRect.size.width = minimumSize.width;
+  if (drawRect.size.height < minimumSize.height)
+    drawRect.size.height = minimumSize.height;
+
+  [NSGraphicsContext saveGraphicsState];
+
+  // Only skip the buffer if the area of our cell (in pixels^2) is too large.
+  if (drawRect.size.width * drawRect.size.height > BITMAP_MAX_AREA) {
+    // Inflate the rect Gecko gave us by the margin for the control.
+    InflateControlRect(&drawRect, controlSize, marginSet);
+
+    NSGraphicsContext* savedContext = [NSGraphicsContext currentContext];
+    [NSGraphicsContext
+        setCurrentContext:[NSGraphicsContext
+                              graphicsContextWithCGContext:cgContext
+                                                   flipped:YES]];
+
+    DrawCellIncludingFocusRing(cell, drawRect, view);
+
+    [NSGraphicsContext setCurrentContext:savedContext];
+  } else {
+    float w = ceil(drawRect.size.width);
+    float h = ceil(drawRect.size.height);
+    NSRect tmpRect = NSMakeRect(kMaxFocusRingWidth, kMaxFocusRingWidth, w, h);
+
+    // inflate to figure out the frame we need to tell NSCell to draw in, to get
+    // something that's 0,0,w,h
+    InflateControlRect(&tmpRect, controlSize, marginSet);
+
+    // and then, expand by kMaxFocusRingWidth size to make sure we can capture
+    // any focus ring
+    w += kMaxFocusRingWidth * 2.0;
+    h += kMaxFocusRingWidth * 2.0;
+
+    int backingScaleFactor = GetBackingScaleFactorForRendering(cgContext);
+    CGColorSpaceRef rgb = CGColorSpaceCreateDeviceRGB();
+    CGContextRef ctx = CGBitmapContextCreate(
+        NULL, (int)w * backingScaleFactor, (int)h * backingScaleFactor, 8,
+        (int)w * backingScaleFactor * 4, rgb, kCGImageAlphaPremultipliedFirst);
+    CGColorSpaceRelease(rgb);
+
+    // We need to flip the image twice in order to avoid drawing bugs on 10.4,
+    // see bug 465069. This is the first flip transform, applied to cgContext.
+    CGContextScaleCTM(cgContext, 1.0f, -1.0f);
+    CGContextTranslateCTM(cgContext, 0.0f,
+                          -(2.0 * destRect.origin.y + destRect.size.height));
+    if (mirrorHorizontal) {
+      CGContextScaleCTM(cgContext, -1.0f, 1.0f);
+      CGContextTranslateCTM(
+          cgContext, -(2.0 * destRect.origin.x + destRect.size.width), 0.0f);
+    }
+
+    NSGraphicsContext* savedContext = [NSGraphicsContext currentContext];
+    [NSGraphicsContext
+        setCurrentContext:[NSGraphicsContext graphicsContextWithCGContext:ctx
+                                                                  flipped:YES]];
+
+    CGContextScaleCTM(ctx, backingScaleFactor, backingScaleFactor);
+
+    // Set the context's "base transform" to in order to get correctly-sized
+    // focus rings.
+    CGContextSetBaseCTM(ctx, CGAffineTransformMakeScale(backingScaleFactor,
+                                                        backingScaleFactor));
+
+    // This is the second flip transform, applied to ctx.
+    CGContextScaleCTM(ctx, 1.0f, -1.0f);
+    CGContextTranslateCTM(ctx, 0.0f,
+                          -(2.0 * tmpRect.origin.y + tmpRect.size.height));
+
+    DrawCellIncludingFocusRing(cell, tmpRect, view);
+
+    [NSGraphicsContext setCurrentContext:savedContext];
+
+    CGImageRef img = CGBitmapContextCreateImage(ctx);
+
+    // Drop the image into the original destination rectangle, scaling to fit
+    // Only scale kMaxFocusRingWidth by xscale/yscale when the resulting rect
+    // doesn't extend beyond the overflow rect
+    float xscale = destRect.size.width / drawRect.size.width;
+    float yscale = destRect.size.height / drawRect.size.height;
+    float scaledFocusRingX =
+        xscale < 1.0f ? kMaxFocusRingWidth * xscale : kMaxFocusRingWidth;
+    float scaledFocusRingY =
+        yscale < 1.0f ? kMaxFocusRingWidth * yscale : kMaxFocusRingWidth;
+    CGContextDrawImage(cgContext,
+                       CGRectMake(destRect.origin.x - scaledFocusRingX,
+                                  destRect.origin.y - scaledFocusRingY,
+                                  destRect.size.width + scaledFocusRingX * 2,
+                                  destRect.size.height + scaledFocusRingY * 2),
+                       img);
+
+    CGImageRelease(img);
+    CGContextRelease(ctx);
+  }
+
+  [NSGraphicsContext restoreGraphicsState];
+
+#if DRAW_IN_FRAME_DEBUG
+  CGContextSetRGBFillColor(cgContext, 0.0, 0.0, 0.5, 0.25);
+  CGContextFillRect(cgContext, destRect);
+#endif
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+struct CellRenderSettings {
+  // The natural dimensions of the control.
+  // If a control has no natural dimensions in either/both axes, set to 0.0f.
+  NSSize naturalSizes[3];
+
+  // The minimum dimensions of the control.
+  // If a control has no minimum dimensions in either/both axes, set to 0.0f.
+  NSSize minimumSizes[3];
+
+  // A three-dimensional array,
+  // with the first dimension being the OS version ([0] 10.6-10.9, [1] 10.10 and
+  // above), the second being the control size (mini, small, regular), and the
+  // third being the 4 margin values (left, top, right, bottom).
+  float margins[2][3][4];
+};
+
+/*
+ * This is a helper method that returns the required NSControlSize given a size
+ * and the size of the three controls plus a tolerance.
+ * size - The width or the height of the element to draw.
+ * sizes - An array with the all the width/height of the element for its
+ *         different sizes.
+ * tolerance - The tolerance as passed to DrawCellWithSnapping.
+ * NOTE: returns NSControlSizeRegular if all values in 'sizes' are zero.
+ */
+static NSControlSize FindControlSize(CGFloat size, const CGFloat* sizes,
+                                     CGFloat tolerance) {
+  for (uint32_t i = miniControlSize; i <= regularControlSize; ++i) {
+    if (sizes[i] == 0) {
+      continue;
+    }
+
+    CGFloat next = 0;
+    // Find next value.
+    for (uint32_t j = i + 1; j <= regularControlSize; ++j) {
+      if (sizes[j] != 0) {
+        next = sizes[j];
+        break;
+      }
+    }
+
+    // If it's the latest value, we pick it.
+    if (next == 0) {
+      return CocoaSizeForEnum(i);
+    }
+
+    if (size <= sizes[i] + tolerance && size < next) {
+      return CocoaSizeForEnum(i);
+    }
+  }
+
+  // If we are here, that means sizes[] was an array with only empty values
+  // or the algorithm above is wrong.
+  // The former can happen but the later would be wrong.
+  NS_ASSERTION(sizes[0] == 0 && sizes[1] == 0 && sizes[2] == 0,
+               "We found no control! We shouldn't be there!");
+  return CocoaSizeForEnum(regularControlSize);
+}
+
+/*
+ * Draw the given NSCell into the given cgContext with a nice control size.
+ *
+ * This function is similar to DrawCellWithScaling, but it decides what
+ * control size to use based on the destRect's size.
+ * Scaling is only applied when the difference between the destRect's size
+ * and the next smaller natural size is greater than snapTolerance. Otherwise
+ * it snaps to the next smaller control size without scaling because unscaled
+ * controls look nicer.
+ */
+static void DrawCellWithSnapping(NSCell* cell, CGContextRef cgContext,
+                                 const HIRect& destRect,
+                                 const CellRenderSettings settings,
+                                 float verticalAlignFactor, NSView* view,
+                                 BOOL mirrorHorizontal,
+                                 float snapTolerance = 2.0f) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  const float rectWidth = destRect.size.width,
+              rectHeight = destRect.size.height;
+  const NSSize* sizes = settings.naturalSizes;
+  const NSSize miniSize = sizes[EnumSizeForCocoaSize(NSControlSizeMini)];
+  const NSSize smallSize = sizes[EnumSizeForCocoaSize(NSControlSizeSmall)];
+  const NSSize regularSize = sizes[EnumSizeForCocoaSize(NSControlSizeRegular)];
+
+  HIRect drawRect = destRect;
+
+  CGFloat controlWidths[3] = {miniSize.width, smallSize.width,
+                              regularSize.width};
+  NSControlSize controlSizeX =
+      FindControlSize(rectWidth, controlWidths, snapTolerance);
+  CGFloat controlHeights[3] = {miniSize.height, smallSize.height,
+                               regularSize.height};
+  NSControlSize controlSizeY =
+      FindControlSize(rectHeight, controlHeights, snapTolerance);
+
+  NSControlSize controlSize = NSControlSizeRegular;
+  size_t sizeIndex = 0;
+
+  // At some sizes, don't scale but snap.
+  const NSControlSize smallerControlSize =
+      EnumSizeForCocoaSize(controlSizeX) < EnumSizeForCocoaSize(controlSizeY)
+          ? controlSizeX
+          : controlSizeY;
+  const size_t smallerControlSizeIndex =
+      EnumSizeForCocoaSize(smallerControlSize);
+  const NSSize size = sizes[smallerControlSizeIndex];
+  float diffWidth = size.width ? rectWidth - size.width : 0.0f;
+  float diffHeight = size.height ? rectHeight - size.height : 0.0f;
+  if (diffWidth >= 0.0f && diffHeight >= 0.0f && diffWidth <= snapTolerance &&
+      diffHeight <= snapTolerance) {
+    // Snap to the smaller control size.
+    controlSize = smallerControlSize;
+    sizeIndex = smallerControlSizeIndex;
+    MOZ_ASSERT(sizeIndex < ArrayLength(settings.naturalSizes));
+
+    // Resize and center the drawRect.
+    if (sizes[sizeIndex].width) {
+      drawRect.origin.x +=
+          ceil((destRect.size.width - sizes[sizeIndex].width) / 2);
+      drawRect.size.width = sizes[sizeIndex].width;
+    }
+    if (sizes[sizeIndex].height) {
+      drawRect.origin.y +=
+          floor((destRect.size.height - sizes[sizeIndex].height) *
+                verticalAlignFactor);
+      drawRect.size.height = sizes[sizeIndex].height;
+    }
+  } else {
+    // Use the larger control size.
+    controlSize =
+        EnumSizeForCocoaSize(controlSizeX) > EnumSizeForCocoaSize(controlSizeY)
+            ? controlSizeX
+            : controlSizeY;
+    sizeIndex = EnumSizeForCocoaSize(controlSize);
+  }
+
+  [cell setControlSize:controlSize];
+
+  MOZ_ASSERT(sizeIndex < ArrayLength(settings.minimumSizes));
+  const NSSize minimumSize = settings.minimumSizes[sizeIndex];
+  DrawCellWithScaling(cell, cgContext, drawRect, controlSize, sizes[sizeIndex],
+                      minimumSize, settings.margins, view, mirrorHorizontal);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+@interface NSWindow (CoreUIRendererPrivate)
++ (CUIRendererRef)coreUIRenderer;
+@end
+
+@interface NSObject (NSAppearanceCoreUIRendering)
+- (void)_drawInRect:(CGRect)rect
+            context:(CGContextRef)cgContext
+            options:(id)options;
+@end
+
+static void RenderWithCoreUI(CGRect aRect, CGContextRef cgContext,
+                             NSDictionary* aOptions,
+                             bool aSkipAreaCheck = false) {
+  if (!aSkipAreaCheck &&
+      aRect.size.width * aRect.size.height > BITMAP_MAX_AREA) {
+    return;
+  }
+
+  NSAppearance* appearance = NSAppearance.currentAppearance;
+  if (appearance &&
+      [appearance respondsToSelector:@selector(_drawInRect:context:options:)]) {
+    // Render through NSAppearance on Mac OS 10.10 and up. This will call
+    // CUIDraw with a CoreUI renderer that will give us the correct 10.10
+    // style. Calling CUIDraw directly with [NSWindow coreUIRenderer] still
+    // renders 10.9-style widgets on 10.10.
+    [appearance _drawInRect:aRect context:cgContext options:aOptions];
+  } else {
+    // 10.9 and below
+    CUIRendererRef renderer =
+        [NSWindow respondsToSelector:@selector(coreUIRenderer)]
+            ? [NSWindow coreUIRenderer]
+            : nil;
+    CUIDraw(renderer, aRect, cgContext, (CFDictionaryRef)aOptions, NULL);
+  }
+}
+
+static float VerticalAlignFactor(nsIFrame* aFrame) {
+  if (!aFrame) return 0.5f;  // default: center
+
+  const auto& va = aFrame->StyleDisplay()->mVerticalAlign;
+  auto kw = va.IsKeyword() ? va.AsKeyword() : StyleVerticalAlignKeyword::Middle;
+  switch (kw) {
+    case StyleVerticalAlignKeyword::Top:
+    case StyleVerticalAlignKeyword::TextTop:
+      return 0.0f;
+
+    case StyleVerticalAlignKeyword::Sub:
+    case StyleVerticalAlignKeyword::Super:
+    case StyleVerticalAlignKeyword::Middle:
+    case StyleVerticalAlignKeyword::MozMiddleWithBaseline:
+      return 0.5f;
+
+    case StyleVerticalAlignKeyword::Baseline:
+    case StyleVerticalAlignKeyword::Bottom:
+    case StyleVerticalAlignKeyword::TextBottom:
+      return 1.0f;
+
+    default:
+      MOZ_ASSERT_UNREACHABLE("invalid vertical-align");
+      return 0.5f;
+  }
+}
+
+static void ApplyControlParamsToNSCell(
+    nsNativeThemeCocoa::ControlParams aControlParams, NSCell* aCell) {
+  [aCell setEnabled:!aControlParams.disabled];
+  [aCell setShowsFirstResponder:(aControlParams.focused &&
+                                 !aControlParams.disabled &&
+                                 aControlParams.insideActiveWindow)];
+  [aCell setHighlighted:aControlParams.pressed];
+}
+
+// These are the sizes that Gecko needs to request to draw if it wants
+// to get a standard-sized Aqua radio button drawn. Note that the rects
+// that draw these are actually a little bigger.
+static const CellRenderSettings radioSettings = {
+    {
+        NSMakeSize(11, 11),  // mini
+        NSMakeSize(13, 13),  // small
+        NSMakeSize(16, 16)   // regular
+    },
+    {NSZeroSize, NSZeroSize, NSZeroSize},
+    {{
+         // Leopard
+         {0, 0, 0, 0},  // mini
+         {0, 1, 1, 1},  // small
+         {0, 0, 0, 0}   // regular
+     },
+     {
+         // Yosemite
+         {0, 0, 0, 0},  // mini
+         {1, 1, 1, 2},  // small
+         {0, 0, 0, 0}   // regular
+     }}};
+
+static const CellRenderSettings checkboxSettings = {
+    {
+        NSMakeSize(11, 11),  // mini
+        NSMakeSize(13, 13),  // small
+        NSMakeSize(16, 16)   // regular
+    },
+    {NSZeroSize, NSZeroSize, NSZeroSize},
+    {{
+         // Leopard
+         {0, 1, 0, 0},  // mini
+         {0, 1, 0, 1},  // small
+         {0, 1, 0, 1}   // regular
+     },
+     {
+         // Yosemite
+         {0, 1, 0, 0},  // mini
+         {0, 1, 0, 1},  // small
+         {0, 1, 0, 1}   // regular
+     }}};
+
+static NSControlStateValue CellStateForCheckboxOrRadioState(
+    nsNativeThemeCocoa::CheckboxOrRadioState aState) {
+  switch (aState) {
+    case nsNativeThemeCocoa::CheckboxOrRadioState::eOff:
+      return NSControlStateValueOff;
+    case nsNativeThemeCocoa::CheckboxOrRadioState::eOn:
+      return NSControlStateValueOn;
+    case nsNativeThemeCocoa::CheckboxOrRadioState::eIndeterminate:
+      return NSControlStateValueMixed;
+  }
+}
+
+void nsNativeThemeCocoa::DrawCheckboxOrRadio(
+    CGContextRef cgContext, bool inCheckbox, const HIRect& inBoxRect,
+    const CheckboxOrRadioParams& aParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NSButtonCell* cell = inCheckbox ? mCheckboxCell : mRadioButtonCell;
+  ApplyControlParamsToNSCell(aParams.controlParams, cell);
+
+  [cell setState:CellStateForCheckboxOrRadioState(aParams.state)];
+  [cell setControlTint:(aParams.controlParams.insideActiveWindow
+                            ? [NSColor currentControlTint]
+                            : NSClearControlTint)];
+
+  // Ensure that the control is square.
+  float length = std::min(inBoxRect.size.width, inBoxRect.size.height);
+  HIRect drawRect = CGRectMake(
+      inBoxRect.origin.x + (int)((inBoxRect.size.width - length) / 2.0f),
+      inBoxRect.origin.y + (int)((inBoxRect.size.height - length) / 2.0f),
+      length, length);
+
+  if (mCellDrawWindow) {
+    mCellDrawWindow.cellsShouldLookActive =
+        aParams.controlParams.insideActiveWindow;
+  }
+  DrawCellWithSnapping(cell, cgContext, drawRect,
+                       inCheckbox ? checkboxSettings : radioSettings,
+                       aParams.verticalAlignFactor, mCellDrawView, NO);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+static const CellRenderSettings searchFieldSettings = {
+    {
+        NSMakeSize(0, 16),  // mini
+        NSMakeSize(0, 19),  // small
+        NSMakeSize(0, 22)   // regular
+    },
+    {
+        NSMakeSize(32, 0),  // mini
+        NSMakeSize(38, 0),  // small
+        NSMakeSize(44, 0)   // regular
+    },
+    {{
+         // Leopard
+         {0, 0, 0, 0},  // mini
+         {0, 0, 0, 0},  // small
+         {0, 0, 0, 0}   // regular
+     },
+     {
+         // Yosemite
+         {0, 0, 0, 0},  // mini
+         {0, 0, 0, 0},  // small
+         {0, 0, 0, 0}   // regular
+     }}};
+
+static bool IsToolbarStyleContainer(nsIFrame* aFrame) {
+  nsIContent* content = aFrame->GetContent();
+  if (!content) {
+    return false;
+  }
+
+  if (content->IsAnyOfXULElements(nsGkAtoms::toolbar, nsGkAtoms::toolbox,
+                                  nsGkAtoms::statusbar)) {
+    return true;
+  }
+
+  switch (aFrame->StyleDisplay()->EffectiveAppearance()) {
+    case StyleAppearance::Toolbar:
+    case StyleAppearance::Statusbar:
+      return true;
+    default:
+      return false;
+  }
+}
+
+static bool IsInsideToolbar(nsIFrame* aFrame) {
+  for (nsIFrame* frame = aFrame; frame; frame = frame->GetParent()) {
+    if (IsToolbarStyleContainer(frame)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+nsNativeThemeCocoa::TextFieldParams nsNativeThemeCocoa::ComputeTextFieldParams(
+    nsIFrame* aFrame, ElementState aEventState) {
+  TextFieldParams params;
+  params.insideToolbar = IsInsideToolbar(aFrame);
+  params.disabled = aEventState.HasState(ElementState::DISABLED);
+
+  // See ShouldUnconditionallyDrawFocusRingIfFocused.
+  params.focused = aEventState.HasState(ElementState::FOCUS);
+
+  params.rtl = IsFrameRTL(aFrame);
+  params.verticalAlignFactor = VerticalAlignFactor(aFrame);
+  return params;
+}
+
+void nsNativeThemeCocoa::DrawTextField(CGContextRef cgContext,
+                                       const HIRect& inBoxRect,
+                                       const TextFieldParams& aParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NSTextFieldCell* cell = mTextFieldCell;
+  [cell setEnabled:!aParams.disabled];
+  [cell setShowsFirstResponder:aParams.focused];
+
+  if (mCellDrawWindow) {
+    mCellDrawWindow.cellsShouldLookActive =
+        YES;  // TODO: propagate correct activeness state
+  }
+  DrawCellWithSnapping(cell, cgContext, inBoxRect, searchFieldSettings,
+                       aParams.verticalAlignFactor, mCellDrawView, aParams.rtl);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsNativeThemeCocoa::DrawSearchField(CGContextRef cgContext,
+                                         const HIRect& inBoxRect,
+                                         const TextFieldParams& aParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  mSearchFieldCell.enabled = !aParams.disabled;
+  mSearchFieldCell.showsFirstResponder = aParams.focused;
+  mSearchFieldCell.placeholderString = @"";
+  mSearchFieldCell.shouldUseToolbarStyle = aParams.insideToolbar;
+
+  if (mCellDrawWindow) {
+    mCellDrawWindow.cellsShouldLookActive =
+        YES;  // TODO: propagate correct activeness state
+  }
+  DrawCellWithSnapping(mSearchFieldCell, cgContext, inBoxRect,
+                       searchFieldSettings, aParams.verticalAlignFactor,
+                       mCellDrawView, aParams.rtl);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+static bool ShouldUnconditionallyDrawFocusRingIfFocused(nsIFrame* aFrame) {
+  // Mac always draws focus rings for textboxes and lists.
+  switch (aFrame->StyleDisplay()->EffectiveAppearance()) {
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Searchfield:
+    case StyleAppearance::Listbox:
+      return true;
+    default:
+      return false;
+  }
+}
+
+nsNativeThemeCocoa::ControlParams nsNativeThemeCocoa::ComputeControlParams(
+    nsIFrame* aFrame, ElementState aEventState) {
+  ControlParams params;
+  params.disabled = aEventState.HasState(ElementState::DISABLED);
+  params.insideActiveWindow = FrameIsInActiveWindow(aFrame);
+  params.pressed =
+      aEventState.HasAllStates(ElementState::ACTIVE | ElementState::HOVER);
+  params.focused = aEventState.HasState(ElementState::FOCUS) &&
+                   (aEventState.HasState(ElementState::FOCUSRING) ||
+                    ShouldUnconditionallyDrawFocusRingIfFocused(aFrame));
+  params.rtl = IsFrameRTL(aFrame);
+  return params;
+}
+
+static const NSSize kHelpButtonSize = NSMakeSize(20, 20);
+static const NSSize kDisclosureButtonSize = NSMakeSize(21, 21);
+
+static const CellRenderSettings pushButtonSettings = {
+    {
+        NSMakeSize(0, 16),  // mini
+        NSMakeSize(0, 19),  // small
+        NSMakeSize(0, 22)   // regular
+    },
+    {
+        NSMakeSize(18, 0),  // mini
+        NSMakeSize(26, 0),  // small
+        NSMakeSize(30, 0)   // regular
+    },
+    {{
+         // Leopard
+         {0, 0, 0, 0},  // mini
+         {4, 0, 4, 1},  // small
+         {5, 0, 5, 2}   // regular
+     },
+     {
+         // Yosemite
+         {0, 0, 0, 0},  // mini
+         {4, 0, 4, 1},  // small
+         {5, 0, 5, 2}   // regular
+     }}};
+
+// The height at which we start doing square buttons instead of rounded buttons
+// Rounded buttons look bad if drawn at a height greater than 26, so at that
+// point we switch over to doing square buttons which looks fine at any size.
+#define DO_SQUARE_BUTTON_HEIGHT 26
+
+void nsNativeThemeCocoa::DrawPushButton(CGContextRef cgContext,
+                                        const HIRect& inBoxRect,
+                                        ButtonType aButtonType,
+                                        ControlParams aControlParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  ApplyControlParamsToNSCell(aControlParams, mPushButtonCell);
+  [mPushButtonCell setBezelStyle:NSBezelStyleRounded];
+  mPushButtonCell.keyEquivalent =
+      aButtonType == ButtonType::eDefaultPushButton ? @"\r" : @"";
+
+  if (mCellDrawWindow) {
+    mCellDrawWindow.cellsShouldLookActive = aControlParams.insideActiveWindow;
+  }
+  DrawCellWithSnapping(mPushButtonCell, cgContext, inBoxRect,
+                       pushButtonSettings, 0.5f, mCellDrawView,
+                       aControlParams.rtl, 1.0f);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsNativeThemeCocoa::DrawSquareBezelPushButton(
+    CGContextRef cgContext, const HIRect& inBoxRect,
+    ControlParams aControlParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  ApplyControlParamsToNSCell(aControlParams, mPushButtonCell);
+  [mPushButtonCell setBezelStyle:NSBezelStyleShadowlessSquare];
+
+  if (mCellDrawWindow) {
+    mCellDrawWindow.cellsShouldLookActive = aControlParams.insideActiveWindow;
+  }
+  DrawCellWithScaling(mPushButtonCell, cgContext, inBoxRect,
+                      NSControlSizeRegular, NSZeroSize, NSMakeSize(14, 0), NULL,
+                      mCellDrawView, aControlParams.rtl);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsNativeThemeCocoa::DrawHelpButton(CGContextRef cgContext,
+                                        const HIRect& inBoxRect,
+                                        ControlParams aControlParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  ApplyControlParamsToNSCell(aControlParams, mHelpButtonCell);
+
+  if (mCellDrawWindow) {
+    mCellDrawWindow.cellsShouldLookActive = aControlParams.insideActiveWindow;
+  }
+  DrawCellWithScaling(mHelpButtonCell, cgContext, inBoxRect,
+                      NSControlSizeRegular, NSZeroSize, kHelpButtonSize, NULL,
+                      mCellDrawView,
+                      false);  // Don't mirror icon in RTL.
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsNativeThemeCocoa::DrawDisclosureButton(CGContextRef cgContext,
+                                              const HIRect& inBoxRect,
+                                              ControlParams aControlParams,
+                                              NSControlStateValue aCellState) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  ApplyControlParamsToNSCell(aControlParams, mDisclosureButtonCell);
+  [mDisclosureButtonCell setState:aCellState];
+
+  if (mCellDrawWindow) {
+    mCellDrawWindow.cellsShouldLookActive = aControlParams.insideActiveWindow;
+  }
+  DrawCellWithScaling(mDisclosureButtonCell, cgContext, inBoxRect,
+                      NSControlSizeRegular, NSZeroSize, kDisclosureButtonSize,
+                      NULL, mCellDrawView,
+                      false);  // Don't mirror icon in RTL.
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+typedef void (*RenderHIThemeControlFunction)(CGContextRef cgContext,
+                                             const HIRect& aRenderRect,
+                                             void* aData);
+
+static void RenderTransformedHIThemeControl(CGContextRef aCGContext,
+                                            const HIRect& aRect,
+                                            RenderHIThemeControlFunction aFunc,
+                                            void* aData,
+                                            BOOL mirrorHorizontally = NO) {
+  CGAffineTransform savedCTM = CGContextGetCTM(aCGContext);
+  CGContextTranslateCTM(aCGContext, aRect.origin.x, aRect.origin.y);
+
+  bool drawDirect;
+  HIRect drawRect = aRect;
+  drawRect.origin = CGPointZero;
+
+  if (!mirrorHorizontally && savedCTM.a == 1.0f && savedCTM.b == 0.0f &&
+      savedCTM.c == 0.0f && (savedCTM.d == 1.0f || savedCTM.d == -1.0f)) {
+    drawDirect = TRUE;
+  } else {
+    drawDirect = FALSE;
+  }
+
+  // Fall back to no bitmap buffer if the area of our control (in pixels^2)
+  // is too large.
+  if (drawDirect || (aRect.size.width * aRect.size.height > BITMAP_MAX_AREA)) {
+    aFunc(aCGContext, drawRect, aData);
+  } else {
+    // Inflate the buffer to capture focus rings.
+    int w = ceil(drawRect.size.width) + 2 * kMaxFocusRingWidth;
+    int h = ceil(drawRect.size.height) + 2 * kMaxFocusRingWidth;
+
+    int backingScaleFactor = GetBackingScaleFactorForRendering(aCGContext);
+    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
+    CGContextRef bitmapctx = CGBitmapContextCreate(
+        NULL, w * backingScaleFactor, h * backingScaleFactor, 8,
+        w * backingScaleFactor * 4, colorSpace,
+        kCGImageAlphaPremultipliedFirst);
+    CGColorSpaceRelease(colorSpace);
+
+    CGContextScaleCTM(bitmapctx, backingScaleFactor, backingScaleFactor);
+    CGContextTranslateCTM(bitmapctx, kMaxFocusRingWidth, kMaxFocusRingWidth);
+
+    // Set the context's "base transform" to in order to get correctly-sized
+    // focus rings.
+    CGContextSetBaseCTM(bitmapctx, CGAffineTransformMakeScale(
+                                       backingScaleFactor, backingScaleFactor));
+
+    // HITheme always wants to draw into a flipped context, or things
+    // get confused.
+    CGContextTranslateCTM(bitmapctx, 0.0f, aRect.size.height);
+    CGContextScaleCTM(bitmapctx, 1.0f, -1.0f);
+
+    aFunc(bitmapctx, drawRect, aData);
+
+    CGImageRef bitmap = CGBitmapContextCreateImage(bitmapctx);
+
+    CGAffineTransform ctm = CGContextGetCTM(aCGContext);
+
+    // We need to unflip, so that we can do a DrawImage without getting a
+    // flipped image.
+    CGContextTranslateCTM(aCGContext, 0.0f, aRect.size.height);
+    CGContextScaleCTM(aCGContext, 1.0f, -1.0f);
+
+    if (mirrorHorizontally) {
+      CGContextTranslateCTM(aCGContext, aRect.size.width, 0);
+      CGContextScaleCTM(aCGContext, -1.0f, 1.0f);
+    }
+
+    HIRect inflatedDrawRect =
+        CGRectMake(-kMaxFocusRingWidth, -kMaxFocusRingWidth, w, h);
+    CGContextDrawImage(aCGContext, inflatedDrawRect, bitmap);
+
+    CGContextSetCTM(aCGContext, ctm);
+
+    CGImageRelease(bitmap);
+    CGContextRelease(bitmapctx);
+  }
+
+  CGContextSetCTM(aCGContext, savedCTM);
+}
+
+static void RenderButton(CGContextRef cgContext, const HIRect& aRenderRect,
+                         void* aData) {
+  HIThemeButtonDrawInfo* bdi = (HIThemeButtonDrawInfo*)aData;
+  HIThemeDrawButton(&aRenderRect, bdi, cgContext, kHIThemeOrientationNormal,
+                    NULL);
+}
+
+static ThemeDrawState ToThemeDrawState(
+    const nsNativeThemeCocoa::ControlParams& aParams) {
+  if (aParams.disabled) {
+    return kThemeStateUnavailable;
+  }
+  if (aParams.pressed) {
+    return kThemeStatePressed;
+  }
+  return kThemeStateActive;
+}
+
+void nsNativeThemeCocoa::DrawHIThemeButton(
+    CGContextRef cgContext, const HIRect& aRect, ThemeButtonKind aKind,
+    ThemeButtonValue aValue, ThemeDrawState aState,
+    ThemeButtonAdornment aAdornment, const ControlParams& aParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  HIThemeButtonDrawInfo bdi;
+  bdi.version = 0;
+  bdi.kind = aKind;
+  bdi.value = aValue;
+  bdi.state = aState;
+  bdi.adornment = aAdornment;
+
+  if (aParams.focused && aParams.insideActiveWindow) {
+    bdi.adornment |= kThemeAdornmentFocus;
+  }
+
+  RenderTransformedHIThemeControl(cgContext, aRect, RenderButton, &bdi,
+                                  aParams.rtl);
+
+#if DRAW_IN_FRAME_DEBUG
+  CGContextSetRGBFillColor(cgContext, 0.0, 0.0, 0.5, 0.25);
+  CGContextFillRect(cgContext, inBoxRect);
+#endif
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsNativeThemeCocoa::DrawButton(CGContextRef cgContext,
+                                    const HIRect& inBoxRect,
+                                    const ButtonParams& aParams) {
+  ControlParams controlParams = aParams.controlParams;
+
+  switch (aParams.button) {
+    case ButtonType::eRegularPushButton:
+    case ButtonType::eDefaultPushButton:
+      DrawPushButton(cgContext, inBoxRect, aParams.button, controlParams);
+      return;
+    case ButtonType::eSquareBezelPushButton:
+      DrawSquareBezelPushButton(cgContext, inBoxRect, controlParams);
+      return;
+    case ButtonType::eArrowButton:
+      DrawHIThemeButton(cgContext, inBoxRect, kThemeArrowButton, kThemeButtonOn,
+                        kThemeStateUnavailable, kThemeAdornmentArrowDownArrow,
+                        controlParams);
+      return;
+    case ButtonType::eHelpButton:
+      DrawHelpButton(cgContext, inBoxRect, controlParams);
+      return;
+    case ButtonType::eTreeTwistyPointingRight:
+      DrawHIThemeButton(cgContext, inBoxRect, kThemeDisclosureButton,
+                        kThemeDisclosureRight, ToThemeDrawState(controlParams),
+                        kThemeAdornmentNone, controlParams);
+      return;
+    case ButtonType::eTreeTwistyPointingDown:
+      DrawHIThemeButton(cgContext, inBoxRect, kThemeDisclosureButton,
+                        kThemeDisclosureDown, ToThemeDrawState(controlParams),
+                        kThemeAdornmentNone, controlParams);
+      return;
+    case ButtonType::eDisclosureButtonClosed:
+      DrawDisclosureButton(cgContext, inBoxRect, controlParams,
+                           NSControlStateValueOff);
+      return;
+    case ButtonType::eDisclosureButtonOpen:
+      DrawDisclosureButton(cgContext, inBoxRect, controlParams,
+                           NSControlStateValueOn);
+      return;
+  }
+}
+
+nsNativeThemeCocoa::TreeHeaderCellParams
+nsNativeThemeCocoa::ComputeTreeHeaderCellParams(nsIFrame* aFrame,
+                                                ElementState aEventState) {
+  TreeHeaderCellParams params;
+  params.controlParams = ComputeControlParams(aFrame, aEventState);
+  params.sortDirection = GetTreeSortDirection(aFrame);
+  params.lastTreeHeaderCell = IsLastTreeHeaderCell(aFrame);
+  return params;
+}
+
+@interface NSTableHeaderCell (NSTableHeaderCell_setSortable)
+// This method has been present in the same form since at least macOS 10.4.
+- (void)_setSortable:(BOOL)arg1
+    showSortIndicator:(BOOL)arg2
+            ascending:(BOOL)arg3
+             priority:(NSInteger)arg4
+     highlightForSort:(BOOL)arg5;
+@end
+
+void nsNativeThemeCocoa::DrawTreeHeaderCell(
+    CGContextRef cgContext, const HIRect& inBoxRect,
+    const TreeHeaderCellParams& aParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Without clearing the cell's title, it takes on a default value of "Field",
+  // which is displayed underneath the title set in the front-end.
+  NSCell* cell = (NSCell*)mTreeHeaderCell;
+  cell.title = @"";
+
+  if ([mTreeHeaderCell
+          respondsToSelector:@selector
+          (_setSortable:
+              showSortIndicator:ascending:priority:highlightForSort:)]) {
+    switch (aParams.sortDirection) {
+      case eTreeSortDirection_Ascending:
+        [mTreeHeaderCell _setSortable:YES
+                    showSortIndicator:YES
+                            ascending:YES
+                             priority:0
+                     highlightForSort:YES];
+        break;
+      case eTreeSortDirection_Descending:
+        [mTreeHeaderCell _setSortable:YES
+                    showSortIndicator:YES
+                            ascending:NO
+                             priority:0
+                     highlightForSort:YES];
+        break;
+      default:
+        // eTreeSortDirection_Natural
+        [mTreeHeaderCell _setSortable:YES
+                    showSortIndicator:NO
+                            ascending:YES
+                             priority:0
+                     highlightForSort:NO];
+        break;
+    }
+  }
+
+  mTreeHeaderCell.enabled = !aParams.controlParams.disabled;
+  mTreeHeaderCell.state =
+      (mTreeHeaderCell.enabled && aParams.controlParams.pressed)
+          ? NSControlStateValueOn
+          : NSControlStateValueOff;
+
+  mCellDrawView._drawingEndSeparator = !aParams.lastTreeHeaderCell;
+
+  NSGraphicsContext* savedContext = NSGraphicsContext.currentContext;
+  NSGraphicsContext.currentContext =
+      [NSGraphicsContext graphicsContextWithCGContext:cgContext flipped:YES];
+  DrawCellIncludingFocusRing(mTreeHeaderCell, inBoxRect, mCellDrawView);
+  NSGraphicsContext.currentContext = savedContext;
+
+#if DRAW_IN_FRAME_DEBUG
+  CGContextSetRGBFillColor(cgContext, 0.0, 0.0, 0.5, 0.25);
+  CGContextFillRect(cgContext, inBoxRect);
+#endif
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+static const CellRenderSettings dropdownSettings = {
+    {
+        NSMakeSize(0, 16),  // mini
+        NSMakeSize(0, 19),  // small
+        NSMakeSize(0, 22)   // regular
+    },
+    {
+        NSMakeSize(18, 0),  // mini
+        NSMakeSize(38, 0),  // small
+        NSMakeSize(44, 0)   // regular
+    },
+    {{
+         // Leopard
+         {1, 1, 2, 1},  // mini
+         {3, 0, 3, 1},  // small
+         {3, 0, 3, 0}   // regular
+     },
+     {
+         // Yosemite
+         {1, 1, 2, 1},  // mini
+         {3, 0, 3, 1},  // small
+         {3, 0, 3, 0}   // regular
+     }}};
+
+static const CellRenderSettings editableMenulistSettings = {
+    {
+        NSMakeSize(0, 15),  // mini
+        NSMakeSize(0, 18),  // small
+        NSMakeSize(0, 21)   // regular
+    },
+    {
+        NSMakeSize(18, 0),  // mini
+        NSMakeSize(38, 0),  // small
+        NSMakeSize(44, 0)   // regular
+    },
+    {{
+         // Leopard
+         {0, 0, 2, 2},  // mini
+         {0, 0, 3, 2},  // small
+         {0, 1, 3, 3}   // regular
+     },
+     {
+         // Yosemite
+         {0, 0, 2, 2},  // mini
+         {0, 0, 3, 2},  // small
+         {0, 1, 3, 3}   // regular
+     }}};
+
+void nsNativeThemeCocoa::DrawDropdown(CGContextRef cgContext,
+                                      const HIRect& inBoxRect,
+                                      const DropdownParams& aParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [mDropdownCell setPullsDown:aParams.pullsDown];
+  NSCell* cell =
+      aParams.editable ? (NSCell*)mComboBoxCell : (NSCell*)mDropdownCell;
+
+  ApplyControlParamsToNSCell(aParams.controlParams, cell);
+
+  if (aParams.controlParams.insideActiveWindow) {
+    [cell setControlTint:[NSColor currentControlTint]];
+  } else {
+    [cell setControlTint:NSClearControlTint];
+  }
+
+  const CellRenderSettings& settings =
+      aParams.editable ? editableMenulistSettings : dropdownSettings;
+
+  if (mCellDrawWindow) {
+    mCellDrawWindow.cellsShouldLookActive =
+        aParams.controlParams.insideActiveWindow;
+  }
+  DrawCellWithSnapping(cell, cgContext, inBoxRect, settings, 0.5f,
+                       mCellDrawView, aParams.controlParams.rtl);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+static const CellRenderSettings spinnerSettings = {
+    {
+        NSMakeSize(11,
+                   16),  // mini (width trimmed by 2px to reduce blank border)
+        NSMakeSize(15, 22),  // small
+        NSMakeSize(19, 27)   // regular
+    },
+    {
+        NSMakeSize(11,
+                   16),  // mini (width trimmed by 2px to reduce blank border)
+        NSMakeSize(15, 22),  // small
+        NSMakeSize(19, 27)   // regular
+    },
+    {{
+         // Leopard
+         {0, 0, 0, 0},  // mini
+         {0, 0, 0, 0},  // small
+         {0, 0, 0, 0}   // regular
+     },
+     {
+         // Yosemite
+         {0, 0, 0, 0},  // mini
+         {0, 0, 0, 0},  // small
+         {0, 0, 0, 0}   // regular
+     }}};
+
+HIThemeButtonDrawInfo nsNativeThemeCocoa::SpinButtonDrawInfo(
+    ThemeButtonKind aKind, const SpinButtonParams& aParams) {
+  HIThemeButtonDrawInfo bdi;
+  bdi.version = 0;
+  bdi.kind = aKind;
+  bdi.value = kThemeButtonOff;
+  bdi.adornment = kThemeAdornmentNone;
+
+  if (aParams.disabled) {
+    bdi.state = kThemeStateUnavailable;
+  } else if (aParams.insideActiveWindow && aParams.pressedButton) {
+    if (*aParams.pressedButton == SpinButton::eUp) {
+      bdi.state = kThemeStatePressedUp;
+    } else {
+      bdi.state = kThemeStatePressedDown;
+    }
+  } else {
+    bdi.state = kThemeStateActive;
+  }
+
+  return bdi;
+}
+
+void nsNativeThemeCocoa::DrawSpinButtons(CGContextRef cgContext,
+                                         const HIRect& inBoxRect,
+                                         const SpinButtonParams& aParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  HIThemeButtonDrawInfo bdi = SpinButtonDrawInfo(kThemeIncDecButton, aParams);
+  HIThemeDrawButton(&inBoxRect, &bdi, cgContext, HITHEME_ORIENTATION, NULL);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsNativeThemeCocoa::DrawSpinButton(CGContextRef cgContext,
+                                        const HIRect& inBoxRect,
+                                        SpinButton aDrawnButton,
+                                        const SpinButtonParams& aParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  HIThemeButtonDrawInfo bdi =
+      SpinButtonDrawInfo(kThemeIncDecButtonMini, aParams);
+
+  // Cocoa only allows kThemeIncDecButton to paint the up and down spin buttons
+  // together as a single unit (presumably because when one button is active,
+  // the appearance of both changes (in different ways)). Here we have to paint
+  // both buttons, using clip to hide the one we don't want to paint.
+  HIRect drawRect = inBoxRect;
+  drawRect.size.height *= 2;
+  if (aDrawnButton == SpinButton::eDown) {
+    drawRect.origin.y -= inBoxRect.size.height;
+  }
+
+  // Shift the drawing a little to the left, since cocoa paints with more
+  // blank space around the visual buttons than we'd like:
+  drawRect.origin.x -= 1;
+
+  CGContextSaveGState(cgContext);
+  CGContextClipToRect(cgContext, inBoxRect);
+
+  HIThemeDrawButton(&drawRect, &bdi, cgContext, HITHEME_ORIENTATION, NULL);
+
+  CGContextRestoreGState(cgContext);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+static const CellRenderSettings progressSettings[2][2] = {
+    // Vertical progress bar.
+    {// Determined settings.
+     {{
+          NSZeroSize,         // mini
+          NSMakeSize(10, 0),  // small
+          NSMakeSize(16, 0)   // regular
+      },
+      {NSZeroSize, NSZeroSize, NSZeroSize},
+      {{
+          // Leopard
+          {0, 0, 0, 0},  // mini
+          {1, 1, 1, 1},  // small
+          {1, 1, 1, 1}   // regular
+      }}},
+     // There is no horizontal margin in regular undetermined size.
+     {{
+          NSZeroSize,         // mini
+          NSMakeSize(10, 0),  // small
+          NSMakeSize(16, 0)   // regular
+      },
+      {NSZeroSize, NSZeroSize, NSZeroSize},
+      {{
+           // Leopard
+           {0, 0, 0, 0},  // mini
+           {1, 1, 1, 1},  // small
+           {1, 0, 1, 0}   // regular
+       },
+       {
+           // Yosemite
+           {0, 0, 0, 0},  // mini
+           {1, 1, 1, 1},  // small
+           {1, 0, 1, 0}   // regular
+       }}}},
+    // Horizontal progress bar.
+    {// Determined settings.
+     {{
+          NSZeroSize,         // mini
+          NSMakeSize(0, 10),  // small
+          NSMakeSize(0, 16)   // regular
+      },
+      {NSZeroSize, NSZeroSize, NSZeroSize},
+      {{
+           // Leopard
+           {0, 0, 0, 0},  // mini
+           {1, 1, 1, 1},  // small
+           {1, 1, 1, 1}   // regular
+       },
+       {
+           // Yosemite
+           {0, 0, 0, 0},  // mini
+           {1, 1, 1, 1},  // small
+           {1, 1, 1, 1}   // regular
+       }}},
+     // There is no horizontal margin in regular undetermined size.
+     {{
+          NSZeroSize,         // mini
+          NSMakeSize(0, 10),  // small
+          NSMakeSize(0, 16)   // regular
+      },
+      {NSZeroSize, NSZeroSize, NSZeroSize},
+      {{
+           // Leopard
+           {0, 0, 0, 0},  // mini
+           {1, 1, 1, 1},  // small
+           {0, 1, 0, 1}   // regular
+       },
+       {
+           // Yosemite
+           {0, 0, 0, 0},  // mini
+           {1, 1, 1, 1},  // small
+           {0, 1, 0, 1}   // regular
+       }}}}};
+
+nsNativeThemeCocoa::ProgressParams nsNativeThemeCocoa::ComputeProgressParams(
+    nsIFrame* aFrame, ElementState aEventState, bool aIsHorizontal) {
+  ProgressParams params;
+  params.value = GetProgressValue(aFrame);
+  params.max = GetProgressMaxValue(aFrame);
+  params.verticalAlignFactor = VerticalAlignFactor(aFrame);
+  params.insideActiveWindow = FrameIsInActiveWindow(aFrame);
+  params.indeterminate = aEventState.HasState(ElementState::INDETERMINATE);
+  params.horizontal = aIsHorizontal;
+  params.rtl = IsFrameRTL(aFrame);
+  return params;
+}
+
+void nsNativeThemeCocoa::DrawProgress(CGContextRef cgContext,
+                                      const HIRect& inBoxRect,
+                                      const ProgressParams& aParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  NSProgressBarCell* cell = mProgressBarCell;
+
+  [cell setValue:aParams.value];
+  [cell setMax:aParams.max];
+  [cell setIndeterminate:aParams.indeterminate];
+  [cell setHorizontal:aParams.horizontal];
+  [cell
+      setControlTint:(aParams.insideActiveWindow ? [NSColor currentControlTint]
+                                                 : NSClearControlTint)];
+
+  if (mCellDrawWindow) {
+    mCellDrawWindow.cellsShouldLookActive = aParams.insideActiveWindow;
+  }
+  DrawCellWithSnapping(
+      cell, cgContext, inBoxRect,
+      progressSettings[aParams.horizontal][aParams.indeterminate],
+      aParams.verticalAlignFactor, mCellDrawView, aParams.rtl);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+static const CellRenderSettings meterSetting = {
+    {
+        NSMakeSize(0, 16),  // mini
+        NSMakeSize(0, 16),  // small
+        NSMakeSize(0, 16)   // regular
+    },
+    {NSZeroSize, NSZeroSize, NSZeroSize},
+    {{
+         // Leopard
+         {1, 1, 1, 1},  // mini
+         {1, 1, 1, 1},  // small
+         {1, 1, 1, 1}   // regular
+     },
+     {
+         // Yosemite
+         {1, 1, 1, 1},  // mini
+         {1, 1, 1, 1},  // small
+         {1, 1, 1, 1}   // regular
+     }}};
+
+nsNativeThemeCocoa::MeterParams nsNativeThemeCocoa::ComputeMeterParams(
+    nsIFrame* aFrame) {
+  nsIContent* content = aFrame->GetContent();
+  if (!(content && content->IsHTMLElement(nsGkAtoms::meter))) {
+    return MeterParams();
+  }
+
+  HTMLMeterElement* meterElement = static_cast<HTMLMeterElement*>(content);
+  MeterParams params;
+  params.value = meterElement->Value();
+  params.min = meterElement->Min();
+  params.max = meterElement->Max();
+  ElementState states = meterElement->State();
+  if (states.HasState(ElementState::SUB_OPTIMUM)) {
+    params.optimumState = OptimumState::eSubOptimum;
+  } else if (states.HasState(ElementState::SUB_SUB_OPTIMUM)) {
+    params.optimumState = OptimumState::eSubSubOptimum;
+  }
+  params.horizontal = !IsVerticalMeter(aFrame);
+  params.verticalAlignFactor = VerticalAlignFactor(aFrame);
+  params.rtl = IsFrameRTL(aFrame);
+
+  return params;
+}
+
+void nsNativeThemeCocoa::DrawMeter(CGContextRef cgContext,
+                                   const HIRect& inBoxRect,
+                                   const MeterParams& aParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK
+
+  NSLevelIndicatorCell* cell = mMeterBarCell;
+
+  [cell setMinValue:aParams.min];
+  [cell setMaxValue:aParams.max];
+  [cell setDoubleValue:aParams.value];
+
+  /**
+   * The way HTML and Cocoa defines the meter/indicator widget are different.
+   * So, we are going to use a trick to get the Cocoa widget showing what we
+   * are expecting: we set the warningValue or criticalValue to the current
+   * value when we want to have the widget to be in the warning or critical
+   * state.
+   */
+  switch (aParams.optimumState) {
+    case OptimumState::eOptimum:
+      [cell setWarningValue:aParams.max + 1];
+      [cell setCriticalValue:aParams.max + 1];
+      break;
+    case OptimumState::eSubOptimum:
+      [cell setWarningValue:aParams.value];
+      [cell setCriticalValue:aParams.max + 1];
+      break;
+    case OptimumState::eSubSubOptimum:
+      [cell setWarningValue:aParams.max + 1];
+      [cell setCriticalValue:aParams.value];
+      break;
+  }
+
+  HIRect rect = CGRectStandardize(inBoxRect);
+  BOOL vertical = !aParams.horizontal;
+
+  CGContextSaveGState(cgContext);
+
+  if (vertical) {
+    /**
+     * Cocoa doesn't provide a vertical meter bar so to show one, we have to
+     * show a rotated horizontal meter bar.
+     * Given that we want to show a vertical meter bar, we assume that the rect
+     * has vertical dimensions but we can't correctly draw a meter widget inside
+     * such a rectangle so we need to inverse width and height (and re-position)
+     * to get a rectangle with horizontal dimensions.
+     * Finally, we want to show a vertical meter so we want to rotate the result
+     * so it is vertical. We do that by changing the context.
+     */
+    CGFloat tmp = rect.size.width;
+    rect.size.width = rect.size.height;
+    rect.size.height = tmp;
+    rect.origin.x += rect.size.height / 2.f - rect.size.width / 2.f;
+    rect.origin.y += rect.size.width / 2.f - rect.size.height / 2.f;
+
+    CGContextTranslateCTM(cgContext, CGRectGetMidX(rect), CGRectGetMidY(rect));
+    CGContextRotateCTM(cgContext, -M_PI / 2.f);
+    CGContextTranslateCTM(cgContext, -CGRectGetMidX(rect),
+                          -CGRectGetMidY(rect));
+  }
+
+  if (mCellDrawWindow) {
+    mCellDrawWindow.cellsShouldLookActive =
+        YES;  // TODO: propagate correct activeness state
+  }
+  DrawCellWithSnapping(cell, cgContext, rect, meterSetting,
+                       aParams.verticalAlignFactor, mCellDrawView,
+                       !vertical && aParams.rtl);
+
+  CGContextRestoreGState(cgContext);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK
+}
+
+void nsNativeThemeCocoa::DrawTabPanel(CGContextRef cgContext,
+                                      const HIRect& inBoxRect,
+                                      bool aIsInsideActiveWindow) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  HIThemeTabPaneDrawInfo tpdi;
+
+  tpdi.version = 1;
+  tpdi.state = aIsInsideActiveWindow ? kThemeStateActive : kThemeStateInactive;
+  tpdi.direction = kThemeTabNorth;
+  tpdi.size = kHIThemeTabSizeNormal;
+  tpdi.kind = kHIThemeTabKindNormal;
+
+  HIThemeDrawTabPane(&inBoxRect, &tpdi, cgContext, HITHEME_ORIENTATION);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+Maybe<nsNativeThemeCocoa::ScaleParams>
+nsNativeThemeCocoa::ComputeHTMLScaleParams(nsIFrame* aFrame,
+                                           ElementState aEventState) {
+  nsRangeFrame* rangeFrame = do_QueryFrame(aFrame);
+  if (!rangeFrame) {
+    return Nothing();
+  }
+
+  bool isHorizontal = IsRangeHorizontal(aFrame);
+
+  // ScaleParams requires integer min, max and value. This is purely for
+  // drawing, so we normalize to a range 0-1000 here.
+  ScaleParams params;
+  params.value = int32_t(rangeFrame->GetValueAsFractionOfRange() * 1000);
+  params.min = 0;
+  params.max = 1000;
+  params.reverse = !isHorizontal || rangeFrame->IsRightToLeft();
+  params.insideActiveWindow = FrameIsInActiveWindow(aFrame);
+  params.focused = aEventState.HasState(ElementState::FOCUSRING);
+  params.disabled = aEventState.HasState(ElementState::DISABLED);
+  params.horizontal = isHorizontal;
+  return Some(params);
+}
+
+void nsNativeThemeCocoa::DrawScale(CGContextRef cgContext,
+                                   const HIRect& inBoxRect,
+                                   const ScaleParams& aParams) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  HIThemeTrackDrawInfo tdi;
+
+  tdi.version = 0;
+  tdi.kind = kThemeMediumSlider;
+  tdi.bounds = inBoxRect;
+  tdi.min = aParams.min;
+  tdi.max = aParams.max;
+  tdi.value = aParams.value;
+  tdi.attributes = kThemeTrackShowThumb;
+  if (aParams.horizontal) {
+    tdi.attributes |= kThemeTrackHorizontal;
+  }
+  if (aParams.reverse) {
+    tdi.attributes |= kThemeTrackRightToLeft;
+  }
+  if (aParams.focused) {
+    tdi.attributes |= kThemeTrackHasFocus;
+  }
+  if (aParams.disabled) {
+    tdi.enableState = kThemeTrackDisabled;
+  } else {
+    tdi.enableState =
+        aParams.insideActiveWindow ? kThemeTrackActive : kThemeTrackInactive;
+  }
+  tdi.trackInfo.slider.thumbDir = kThemeThumbPlain;
+  tdi.trackInfo.slider.pressState = 0;
+
+  HIThemeDrawTrack(&tdi, NULL, cgContext, HITHEME_ORIENTATION);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+nsIFrame* nsNativeThemeCocoa::SeparatorResponsibility(nsIFrame* aBefore,
+                                                      nsIFrame* aAfter) {
+  // Usually a separator is drawn by the segment to the right of the
+  // separator, but pressed and selected segments have higher priority.
+  if (!aBefore || !aAfter) return nullptr;
+  if (IsSelectedButton(aAfter)) return aAfter;
+  if (IsSelectedButton(aBefore) || IsPressedButton(aBefore)) return aBefore;
+  return aAfter;
+}
+
+static CGRect SeparatorAdjustedRect(CGRect aRect,
+                                    nsNativeThemeCocoa::SegmentParams aParams) {
+  // A separator between two segments should always be located in the leftmost
+  // pixel column of the segment to the right of the separator, regardless of
+  // who ends up drawing it.
+  // CoreUI draws the separators inside the drawing rect.
+  if (!aParams.atLeftEnd && !aParams.drawsLeftSeparator) {
+    // The segment to the left of us draws the separator, so we need to make
+    // room for it.
+    aRect.origin.x += 1;
+    aRect.size.width -= 1;
+  }
+  if (aParams.drawsRightSeparator) {
+    // We draw the right separator, so we need to extend the draw rect into the
+    // segment to our right.
+    aRect.size.width += 1;
+  }
+  return aRect;
+}
+
+static NSString* ToolbarButtonPosition(BOOL aIsFirst, BOOL aIsLast) {
+  if (aIsFirst) {
+    if (aIsLast) return @"kCUISegmentPositionOnly";
+    return @"kCUISegmentPositionFirst";
+  }
+  if (aIsLast) return @"kCUISegmentPositionLast";
+  return @"kCUISegmentPositionMiddle";
+}
+
+struct SegmentedControlRenderSettings {
+  const CGFloat* heights;
+  const NSString* widgetName;
+};
+
+static const CGFloat tabHeights[3] = {17, 20, 23};
+
+static const SegmentedControlRenderSettings tabRenderSettings = {tabHeights,
+                                                                 @"tab"};
+
+static const CGFloat toolbarButtonHeights[3] = {15, 18, 22};
+
+static const SegmentedControlRenderSettings toolbarButtonRenderSettings = {
+    toolbarButtonHeights, @"kCUIWidgetButtonSegmentedSCurve"};
+
+nsNativeThemeCocoa::SegmentParams nsNativeThemeCocoa::ComputeSegmentParams(
+    nsIFrame* aFrame, ElementState aEventState, SegmentType aSegmentType) {
+  SegmentParams params;
+  params.segmentType = aSegmentType;
+  params.insideActiveWindow = FrameIsInActiveWindow(aFrame);
+  params.pressed = IsPressedButton(aFrame);
+  params.selected = IsSelectedButton(aFrame);
+  params.focused = aEventState.HasState(ElementState::FOCUSRING);
+  bool isRTL = IsFrameRTL(aFrame);
+  nsIFrame* left = GetAdjacentSiblingFrameWithSameAppearance(aFrame, isRTL);
+  nsIFrame* right = GetAdjacentSiblingFrameWithSameAppearance(aFrame, !isRTL);
+  params.atLeftEnd = !left;
+  params.atRightEnd = !right;
+  params.drawsLeftSeparator = SeparatorResponsibility(left, aFrame) == aFrame;
+  params.drawsRightSeparator = SeparatorResponsibility(aFrame, right) == aFrame;
+  params.rtl = isRTL;
+  return params;
+}
+
+static SegmentedControlRenderSettings RenderSettingsForSegmentType(
+    nsNativeThemeCocoa::SegmentType aSegmentType) {
+  switch (aSegmentType) {
+    case nsNativeThemeCocoa::SegmentType::eToolbarButton:
+      return toolbarButtonRenderSettings;
+    case nsNativeThemeCocoa::SegmentType::eTab:
+      return tabRenderSettings;
+  }
+}
+
+void nsNativeThemeCocoa::DrawSegment(CGContextRef cgContext,
+                                     const HIRect& inBoxRect,
+                                     const SegmentParams& aParams) {
+  SegmentedControlRenderSettings renderSettings =
+      RenderSettingsForSegmentType(aParams.segmentType);
+  NSControlSize controlSize =
+      FindControlSize(inBoxRect.size.height, renderSettings.heights, 4.0f);
+  CGRect drawRect = SeparatorAdjustedRect(inBoxRect, aParams);
+
+  NSDictionary* dict = @{
+    @"widget" : renderSettings.widgetName,
+    @"kCUIPresentationStateKey" :
+        (aParams.insideActiveWindow ? @"kCUIPresentationStateActiveKey"
+                                    : @"kCUIPresentationStateInactive"),
+    @"kCUIPositionKey" :
+        ToolbarButtonPosition(aParams.atLeftEnd, aParams.atRightEnd),
+    @"kCUISegmentLeadingSeparatorKey" :
+        [NSNumber numberWithBool:aParams.drawsLeftSeparator],
+    @"kCUISegmentTrailingSeparatorKey" :
+        [NSNumber numberWithBool:aParams.drawsRightSeparator],
+    @"value" : [NSNumber numberWithBool:aParams.selected],
+    @"state" : (aParams.pressed
+                    ? @"pressed"
+                    : (aParams.insideActiveWindow ? @"normal" : @"inactive")),
+    @"focus" : [NSNumber numberWithBool:aParams.focused],
+    @"size" : CUIControlSizeForCocoaSize(controlSize),
+    @"is.flipped" : [NSNumber numberWithBool:YES],
+    @"direction" : @"up"
+  };
+
+  RenderWithCoreUI(drawRect, cgContext, dict);
+}
+
+void nsNativeThemeCocoa::DrawToolbar(CGContextRef cgContext,
+                                     const CGRect& inBoxRect, bool aIsMain) {
+  CGRect drawRect = inBoxRect;
+
+  // top border
+  drawRect.size.height = 1.0f;
+  DrawNativeGreyColorInRect(cgContext, toolbarTopBorderGrey, drawRect, aIsMain);
+
+  // background
+  drawRect.origin.y += drawRect.size.height;
+  drawRect.size.height = inBoxRect.size.height - 2.0f;
+  DrawNativeGreyColorInRect(cgContext, toolbarFillGrey, drawRect, aIsMain);
+
+  // bottom border
+  drawRect.origin.y += drawRect.size.height;
+  drawRect.size.height = 1.0f;
+  DrawNativeGreyColorInRect(cgContext, toolbarBottomBorderGrey, drawRect,
+                            aIsMain);
+}
+
+static bool ToolbarCanBeUnified(const gfx::Rect& aRect, NSWindow* aWindow) {
+  if (![aWindow isKindOfClass:[ToolbarWindow class]]) return false;
+
+  ToolbarWindow* win = (ToolbarWindow*)aWindow;
+  float unifiedToolbarHeight = [win unifiedToolbarHeight];
+  return aRect.X() == 0 && aRect.Width() >= [win frame].size.width &&
+         aRect.YMost() <= unifiedToolbarHeight;
+}
+
+void nsNativeThemeCocoa::DrawStatusBar(CGContextRef cgContext,
+                                       const HIRect& inBoxRect, bool aIsMain) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (inBoxRect.size.height < 2.0f) return;
+
+  CGContextSaveGState(cgContext);
+  CGContextClipToRect(cgContext, inBoxRect);
+
+  // kCUIWidgetWindowFrame draws a complete window frame with both title bar
+  // and bottom bar. We only want the bottom bar, so we extend the draw rect
+  // upwards to make space for the title bar, and then we clip it away.
+  CGRect drawRect = inBoxRect;
+  const int extendUpwards = 40;
+  drawRect.origin.y -= extendUpwards;
+  drawRect.size.height += extendUpwards;
+  RenderWithCoreUI(
+      drawRect, cgContext,
+      [NSDictionary dictionaryWithObjectsAndKeys:
+                        @"kCUIWidgetWindowFrame", @"widget", @"regularwin",
+                        @"windowtype", (aIsMain ? @"normal" : @"inactive"),
+                        @"state",
+                        [NSNumber numberWithInt:inBoxRect.size.height],
+                        @"kCUIWindowFrameBottomBarHeightKey",
+                        [NSNumber numberWithBool:YES],
+                        @"kCUIWindowFrameDrawBottomBarSeparatorKey",
+                        [NSNumber numberWithBool:YES], @"is.flipped", nil]);
+
+  CGContextRestoreGState(cgContext);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsNativeThemeCocoa::DrawMultilineTextField(CGContextRef cgContext,
+                                                const CGRect& inBoxRect,
+                                                bool aIsFocused) {
+  mTextFieldCell.enabled = YES;
+  mTextFieldCell.showsFirstResponder = aIsFocused;
+
+  if (mCellDrawWindow) {
+    mCellDrawWindow.cellsShouldLookActive = YES;
+  }
+
+  // DrawCellIncludingFocusRing draws into the current NSGraphicsContext, so do
+  // the usual save+restore dance.
+  NSGraphicsContext* savedContext = NSGraphicsContext.currentContext;
+  NSGraphicsContext.currentContext =
+      [NSGraphicsContext graphicsContextWithCGContext:cgContext flipped:YES];
+  DrawCellIncludingFocusRing(mTextFieldCell, inBoxRect, mCellDrawView);
+  NSGraphicsContext.currentContext = savedContext;
+}
+
+static bool IsHiDPIContext(nsDeviceContext* aContext) {
+  return AppUnitsPerCSSPixel() >=
+         2 * aContext->AppUnitsPerDevPixelAtUnitFullZoom();
+}
+
+Maybe<nsNativeThemeCocoa::WidgetInfo> nsNativeThemeCocoa::ComputeWidgetInfo(
+    nsIFrame* aFrame, StyleAppearance aAppearance, const nsRect& aRect) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // setup to draw into the correct port
+  int32_t p2a = aFrame->PresContext()->AppUnitsPerDevPixel();
+
+  gfx::Rect nativeWidgetRect(aRect.x, aRect.y, aRect.width, aRect.height);
+  nativeWidgetRect.Scale(1.0 / gfxFloat(p2a));
+  float originalHeight = nativeWidgetRect.Height();
+  nativeWidgetRect.Round();
+  if (nativeWidgetRect.IsEmpty()) {
+    return Nothing();  // Don't attempt to draw invisible widgets.
+  }
+
+  bool hidpi = IsHiDPIContext(aFrame->PresContext()->DeviceContext());
+  if (hidpi) {
+    // Use high-resolution drawing.
+    nativeWidgetRect.Scale(0.5f);
+    originalHeight *= 0.5f;
+  }
+
+  ElementState elementState = GetContentState(aFrame, aAppearance);
+
+  switch (aAppearance) {
+    case StyleAppearance::Menupopup:
+      return Nothing();
+
+    case StyleAppearance::Tooltip:
+      return Nothing();
+
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Radio: {
+      bool isCheckbox = aAppearance == StyleAppearance::Checkbox;
+
+      CheckboxOrRadioParams params;
+      params.state = CheckboxOrRadioState::eOff;
+      if (isCheckbox && elementState.HasState(ElementState::INDETERMINATE)) {
+        params.state = CheckboxOrRadioState::eIndeterminate;
+      } else if (elementState.HasState(ElementState::CHECKED)) {
+        params.state = CheckboxOrRadioState::eOn;
+      }
+      params.controlParams = ComputeControlParams(aFrame, elementState);
+      params.verticalAlignFactor = VerticalAlignFactor(aFrame);
+      if (isCheckbox) {
+        return Some(WidgetInfo::Checkbox(params));
+      }
+      return Some(WidgetInfo::Radio(params));
+    }
+
+    case StyleAppearance::Button:
+      if (IsDefaultButton(aFrame)) {
+        // Check whether the default button is in a document that does not
+        // match the :-moz-window-inactive pseudoclass. This activeness check
+        // is different from the other "active window" checks in this file
+        // because we absolutely need the button's default button appearance to
+        // be in sync with its text color, and the text color is changed by
+        // such a :-moz-window-inactive rule. (That's because on 10.10 and up,
+        // default buttons in active windows have blue background and white
+        // text, and default buttons in inactive windows have white background
+        // and black text.)
+        DocumentState docState = aFrame->PresContext()->Document()->State();
+        ControlParams params = ComputeControlParams(aFrame, elementState);
+        params.insideActiveWindow =
+            !docState.HasState(DocumentState::WINDOW_INACTIVE);
+        return Some(WidgetInfo::Button(
+            ButtonParams{params, ButtonType::eDefaultPushButton}));
+      }
+      if (IsButtonTypeMenu(aFrame)) {
+        ControlParams controlParams =
+            ComputeControlParams(aFrame, elementState);
+        controlParams.pressed = IsOpenButton(aFrame);
+        DropdownParams params;
+        params.controlParams = controlParams;
+        params.pullsDown = true;
+        params.editable = false;
+        return Some(WidgetInfo::Dropdown(params));
+      }
+      if (originalHeight > DO_SQUARE_BUTTON_HEIGHT) {
+        // If the button is tall enough, draw the square button style so that
+        // buttons with non-standard content look good. Otherwise draw normal
+        // rounded aqua buttons.
+        // This comparison is done based on the height that is calculated
+        // without the top, because the snapped height can be affected by the
+        // top of the rect and that may result in different height depending on
+        // the top value.
+        return Some(WidgetInfo::Button(
+            ButtonParams{ComputeControlParams(aFrame, elementState),
+                         ButtonType::eSquareBezelPushButton}));
+      }
+      return Some(WidgetInfo::Button(
+          ButtonParams{ComputeControlParams(aFrame, elementState),
+                       ButtonType::eRegularPushButton}));
+
+    case StyleAppearance::MozMacHelpButton:
+      return Some(WidgetInfo::Button(
+          ButtonParams{ComputeControlParams(aFrame, elementState),
+                       ButtonType::eHelpButton}));
+
+    case StyleAppearance::MozMacDisclosureButtonOpen:
+    case StyleAppearance::MozMacDisclosureButtonClosed: {
+      ButtonType buttonType =
+          (aAppearance == StyleAppearance::MozMacDisclosureButtonClosed)
+              ? ButtonType::eDisclosureButtonClosed
+              : ButtonType::eDisclosureButtonOpen;
+      return Some(WidgetInfo::Button(ButtonParams{
+          ComputeControlParams(aFrame, elementState), buttonType}));
+    }
+
+    case StyleAppearance::Spinner: {
+      bool isSpinner = (aAppearance == StyleAppearance::Spinner);
+      nsIContent* content = aFrame->GetContent();
+      if (isSpinner && content->IsHTMLElement()) {
+        // In HTML the theming for the spin buttons is drawn individually into
+        // their own backgrounds instead of being drawn into the background of
+        // their spinner parent as it is for XUL.
+        break;
+      }
+      SpinButtonParams params;
+      if (content->IsElement()) {
+        if (content->AsElement()->AttrValueIs(
+                kNameSpaceID_None, nsGkAtoms::state, u"up"_ns, eCaseMatters)) {
+          params.pressedButton = Some(SpinButton::eUp);
+        } else if (content->AsElement()->AttrValueIs(
+                       kNameSpaceID_None, nsGkAtoms::state, u"down"_ns,
+                       eCaseMatters)) {
+          params.pressedButton = Some(SpinButton::eDown);
+        }
+      }
+      params.disabled = elementState.HasState(ElementState::DISABLED);
+      params.insideActiveWindow = FrameIsInActiveWindow(aFrame);
+
+      return Some(WidgetInfo::SpinButtons(params));
+    }
+
+    case StyleAppearance::SpinnerUpbutton:
+    case StyleAppearance::SpinnerDownbutton: {
+      nsNumberControlFrame* numberControlFrame =
+          nsNumberControlFrame::GetNumberControlFrameForSpinButton(aFrame);
+      if (numberControlFrame) {
+        SpinButtonParams params;
+        if (numberControlFrame->SpinnerUpButtonIsDepressed()) {
+          params.pressedButton = Some(SpinButton::eUp);
+        } else if (numberControlFrame->SpinnerDownButtonIsDepressed()) {
+          params.pressedButton = Some(SpinButton::eDown);
+        }
+        params.disabled = elementState.HasState(ElementState::DISABLED);
+        params.insideActiveWindow = FrameIsInActiveWindow(aFrame);
+        if (aAppearance == StyleAppearance::SpinnerUpbutton) {
+          return Some(WidgetInfo::SpinButtonUp(params));
+        }
+        return Some(WidgetInfo::SpinButtonDown(params));
+      }
+    } break;
+
+    case StyleAppearance::Toolbarbutton: {
+      SegmentParams params = ComputeSegmentParams(aFrame, elementState,
+                                                  SegmentType::eToolbarButton);
+      params.insideActiveWindow = [NativeWindowForFrame(aFrame) isMainWindow];
+      return Some(WidgetInfo::Segment(params));
+    }
+
+    case StyleAppearance::Separator:
+      return Some(WidgetInfo::Separator());
+
+    case StyleAppearance::Toolbar: {
+      NSWindow* win = NativeWindowForFrame(aFrame);
+      bool isMain = [win isMainWindow];
+      if (ToolbarCanBeUnified(nativeWidgetRect, win)) {
+        // Unified toolbars are drawn similar to vibrancy; we communicate their
+        // extents via the theme geometry mechanism and then place native views
+        // under Gecko's rendering. So Gecko just needs to be transparent in the
+        // place where the toolbar should be visible.
+        return Nothing();
+      }
+      return Some(WidgetInfo::Toolbar(isMain));
+    }
+
+    case StyleAppearance::MozWindowTitlebar: {
+      return Nothing();
+    }
+
+    case StyleAppearance::Statusbar:
+      return Some(WidgetInfo::StatusBar(IsActive(aFrame, YES)));
+
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Menulist: {
+      ControlParams controlParams = ComputeControlParams(aFrame, elementState);
+      controlParams.pressed = IsOpenButton(aFrame);
+      DropdownParams params;
+      params.controlParams = controlParams;
+      params.pullsDown = false;
+      params.editable = false;
+      return Some(WidgetInfo::Dropdown(params));
+    }
+
+    case StyleAppearance::MozMenulistArrowButton:
+      return Some(WidgetInfo::Button(
+          ButtonParams{ComputeControlParams(aFrame, elementState),
+                       ButtonType::eArrowButton}));
+
+    case StyleAppearance::Textfield:
+    case StyleAppearance::NumberInput:
+      return Some(
+          WidgetInfo::TextField(ComputeTextFieldParams(aFrame, elementState)));
+
+    case StyleAppearance::Searchfield:
+      return Some(WidgetInfo::SearchField(
+          ComputeTextFieldParams(aFrame, elementState)));
+
+    case StyleAppearance::ProgressBar: {
+      if (elementState.HasState(ElementState::INDETERMINATE)) {
+        if (!QueueAnimatedContentForRefresh(aFrame->GetContent(), 30)) {
+          NS_WARNING("Unable to animate progressbar!");
+        }
+      }
+      return Some(WidgetInfo::ProgressBar(ComputeProgressParams(
+          aFrame, elementState, !IsVerticalProgress(aFrame))));
+    }
+
+    case StyleAppearance::Meter:
+      return Some(WidgetInfo::Meter(ComputeMeterParams(aFrame)));
+
+    case StyleAppearance::Progresschunk:
+    case StyleAppearance::Meterchunk:
+      // Do nothing: progress and meter bars cases will draw chunks.
+      break;
+
+    case StyleAppearance::Treetwisty:
+      return Some(WidgetInfo::Button(
+          ButtonParams{ComputeControlParams(aFrame, elementState),
+                       ButtonType::eTreeTwistyPointingRight}));
+
+    case StyleAppearance::Treetwistyopen:
+      return Some(WidgetInfo::Button(
+          ButtonParams{ComputeControlParams(aFrame, elementState),
+                       ButtonType::eTreeTwistyPointingDown}));
+
+    case StyleAppearance::Treeheadercell:
+      return Some(WidgetInfo::TreeHeaderCell(
+          ComputeTreeHeaderCellParams(aFrame, elementState)));
+
+    case StyleAppearance::Treeitem:
+    case StyleAppearance::Treeview:
+      return Some(WidgetInfo::ColorFill(sRGBColor(1.0, 1.0, 1.0, 1.0)));
+
+    case StyleAppearance::Treeheader:
+      // do nothing, taken care of by individual header cells
+    case StyleAppearance::Treeline:
+      // do nothing, these lines don't exist on macos
+      break;
+
+    case StyleAppearance::Range: {
+      Maybe<ScaleParams> params = ComputeHTMLScaleParams(aFrame, elementState);
+      if (params) {
+        return Some(WidgetInfo::Scale(*params));
+      }
+      break;
+    }
+
+    case StyleAppearance::Textarea:
+      return Some(WidgetInfo::MultilineTextField(
+          elementState.HasState(ElementState::FOCUS)));
+
+    case StyleAppearance::Listbox:
+      return Some(WidgetInfo::ListBox());
+
+    case StyleAppearance::Tab: {
+      SegmentParams params =
+          ComputeSegmentParams(aFrame, elementState, SegmentType::eTab);
+      params.pressed = params.pressed && !params.selected;
+      return Some(WidgetInfo::Segment(params));
+    }
+
+    case StyleAppearance::Tabpanels:
+      return Some(WidgetInfo::TabPanel(FrameIsInActiveWindow(aFrame)));
+
+    default:
+      break;
+  }
+
+  return Nothing();
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(Nothing());
+}
+
+NS_IMETHODIMP
+nsNativeThemeCocoa::DrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
+                                         StyleAppearance aAppearance,
+                                         const nsRect& aRect,
+                                         const nsRect& aDirtyRect,
+                                         DrawOverflow aDrawOverflow) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return ThemeCocoa::DrawWidgetBackground(aContext, aFrame, aAppearance,
+                                            aRect, aDirtyRect, aDrawOverflow);
+  }
+
+  Maybe<WidgetInfo> widgetInfo = ComputeWidgetInfo(aFrame, aAppearance, aRect);
+
+  if (!widgetInfo) {
+    return NS_OK;
+  }
+
+  int32_t p2a = aFrame->PresContext()->AppUnitsPerDevPixel();
+
+  gfx::Rect nativeWidgetRect = NSRectToRect(aRect, p2a);
+  nativeWidgetRect.Round();
+
+  bool hidpi = IsHiDPIContext(aFrame->PresContext()->DeviceContext());
+
+  auto colorScheme = LookAndFeel::ColorSchemeForFrame(aFrame);
+
+  RenderWidget(*widgetInfo, colorScheme, *aContext->GetDrawTarget(),
+               nativeWidgetRect, NSRectToRect(aDirtyRect, p2a),
+               hidpi ? 2.0f : 1.0f);
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void nsNativeThemeCocoa::RenderWidget(const WidgetInfo& aWidgetInfo,
+                                      LookAndFeel::ColorScheme aScheme,
+                                      DrawTarget& aDrawTarget,
+                                      const gfx::Rect& aWidgetRect,
+                                      const gfx::Rect& aDirtyRect,
+                                      float aScale) {
+  // Some of the drawing below uses NSAppearance.currentAppearance behind the
+  // scenes. Set it to the appearance we want, the same way as
+  // nsLookAndFeel::NativeGetColor.
+  NSAppearance.currentAppearance = NSAppearanceForColorScheme(aScheme);
+
+  // Also set the cell draw window's appearance; this is respected by
+  // NSTextFieldCell (and its subclass NSSearchFieldCell).
+  if (mCellDrawWindow) {
+    mCellDrawWindow.appearance = NSAppearance.currentAppearance;
+  }
+
+  const Widget widget = aWidgetInfo.Widget();
+
+  // Some widgets render using DrawTarget, and some using CGContext.
+  switch (widget) {
+    case Widget::eColorFill: {
+      sRGBColor color = aWidgetInfo.Params<sRGBColor>();
+      aDrawTarget.FillRect(aWidgetRect, ColorPattern(ToDeviceColor(color)));
+      break;
+    }
+    default: {
+      AutoRestoreTransform autoRestoreTransform(&aDrawTarget);
+      gfx::Rect widgetRect = aWidgetRect;
+      gfx::Rect dirtyRect = aDirtyRect;
+
+      dirtyRect.Scale(1.0f / aScale);
+      widgetRect.Scale(1.0f / aScale);
+      aDrawTarget.SetTransform(
+          aDrawTarget.GetTransform().PreScale(aScale, aScale));
+
+      // The remaining widgets require a CGContext.
+      CGRect macRect = CGRectMake(widgetRect.X(), widgetRect.Y(),
+                                  widgetRect.Width(), widgetRect.Height());
+
+      gfxQuartzNativeDrawing nativeDrawing(aDrawTarget, dirtyRect);
+
+      CGContextRef cgContext = nativeDrawing.BeginNativeDrawing();
+      if (cgContext == nullptr) {
+        // The Quartz surface handles 0x0 surfaces by internally
+        // making all operations no-ops; there's no cgcontext created for them.
+        // Unfortunately, this means that callers that want to render
+        // directly to the CGContext need to be aware of this quirk.
+        return;
+      }
+
+      // Set the context's "base transform" to in order to get correctly-sized
+      // focus rings.
+      CGContextSetBaseCTM(cgContext,
+                          CGAffineTransformMakeScale(aScale, aScale));
+
+      switch (widget) {
+        case Widget::eColorFill:
+          MOZ_CRASH("already handled in outer switch");
+          break;
+        case Widget::eCheckbox: {
+          CheckboxOrRadioParams params =
+              aWidgetInfo.Params<CheckboxOrRadioParams>();
+          DrawCheckboxOrRadio(cgContext, true, macRect, params);
+          break;
+        }
+        case Widget::eRadio: {
+          CheckboxOrRadioParams params =
+              aWidgetInfo.Params<CheckboxOrRadioParams>();
+          DrawCheckboxOrRadio(cgContext, false, macRect, params);
+          break;
+        }
+        case Widget::eButton: {
+          ButtonParams params = aWidgetInfo.Params<ButtonParams>();
+          DrawButton(cgContext, macRect, params);
+          break;
+        }
+        case Widget::eDropdown: {
+          DropdownParams params = aWidgetInfo.Params<DropdownParams>();
+          DrawDropdown(cgContext, macRect, params);
+          break;
+        }
+        case Widget::eSpinButtons: {
+          SpinButtonParams params = aWidgetInfo.Params<SpinButtonParams>();
+          DrawSpinButtons(cgContext, macRect, params);
+          break;
+        }
+        case Widget::eSpinButtonUp: {
+          SpinButtonParams params = aWidgetInfo.Params<SpinButtonParams>();
+          DrawSpinButton(cgContext, macRect, SpinButton::eUp, params);
+          break;
+        }
+        case Widget::eSpinButtonDown: {
+          SpinButtonParams params = aWidgetInfo.Params<SpinButtonParams>();
+          DrawSpinButton(cgContext, macRect, SpinButton::eDown, params);
+          break;
+        }
+        case Widget::eSegment: {
+          SegmentParams params = aWidgetInfo.Params<SegmentParams>();
+          DrawSegment(cgContext, macRect, params);
+          break;
+        }
+        case Widget::eSeparator: {
+          HIThemeSeparatorDrawInfo sdi = {0, kThemeStateActive};
+          HIThemeDrawSeparator(&macRect, &sdi, cgContext, HITHEME_ORIENTATION);
+          break;
+        }
+        case Widget::eToolbar: {
+          bool isMain = aWidgetInfo.Params<bool>();
+          DrawToolbar(cgContext, macRect, isMain);
+          break;
+        }
+        case Widget::eStatusBar: {
+          bool isMain = aWidgetInfo.Params<bool>();
+          DrawStatusBar(cgContext, macRect, isMain);
+          break;
+        }
+        case Widget::eGroupBox: {
+          HIThemeGroupBoxDrawInfo gdi = {0, kThemeStateActive,
+                                         kHIThemeGroupBoxKindPrimary};
+          HIThemeDrawGroupBox(&macRect, &gdi, cgContext, HITHEME_ORIENTATION);
+          break;
+        }
+        case Widget::eTextField: {
+          TextFieldParams params = aWidgetInfo.Params<TextFieldParams>();
+          DrawTextField(cgContext, macRect, params);
+          break;
+        }
+        case Widget::eSearchField: {
+          TextFieldParams params = aWidgetInfo.Params<TextFieldParams>();
+          DrawSearchField(cgContext, macRect, params);
+          break;
+        }
+        case Widget::eProgressBar: {
+          ProgressParams params = aWidgetInfo.Params<ProgressParams>();
+          DrawProgress(cgContext, macRect, params);
+          break;
+        }
+        case Widget::eMeter: {
+          MeterParams params = aWidgetInfo.Params<MeterParams>();
+          DrawMeter(cgContext, macRect, params);
+          break;
+        }
+        case Widget::eTreeHeaderCell: {
+          TreeHeaderCellParams params =
+              aWidgetInfo.Params<TreeHeaderCellParams>();
+          DrawTreeHeaderCell(cgContext, macRect, params);
+          break;
+        }
+        case Widget::eScale: {
+          ScaleParams params = aWidgetInfo.Params<ScaleParams>();
+          DrawScale(cgContext, macRect, params);
+          break;
+        }
+        case Widget::eMultilineTextField: {
+          bool isFocused = aWidgetInfo.Params<bool>();
+          DrawMultilineTextField(cgContext, macRect, isFocused);
+          break;
+        }
+        case Widget::eListBox: {
+          // Fill the content with the control background color.
+          CGContextSetFillColorWithColor(
+              cgContext, [NSColor.controlBackgroundColor CGColor]);
+          CGContextFillRect(cgContext, macRect);
+          // Draw the frame using kCUIWidgetScrollViewFrame. This is what
+          // NSScrollView uses in
+          // -[NSScrollView drawRect:] if you give it a borderType of
+          // NSBezelBorder.
+          RenderWithCoreUI(
+              macRect, cgContext, @{
+                @"widget" : @"kCUIWidgetScrollViewFrame",
+                @"kCUIIsFlippedKey" : @YES,
+                @"kCUIVariantMetal" : @NO,
+              });
+          break;
+        }
+        case Widget::eTabPanel: {
+          bool isInsideActiveWindow = aWidgetInfo.Params<bool>();
+          DrawTabPanel(cgContext, macRect, isInsideActiveWindow);
+          break;
+        }
+      }
+
+      // Reset the base CTM.
+      CGContextSetBaseCTM(cgContext, CGAffineTransformIdentity);
+
+      nativeDrawing.EndNativeDrawing();
+    }
+  }
+}
+
+bool nsNativeThemeCocoa::CreateWebRenderCommandsForWidget(
+    mozilla::wr::DisplayListBuilder& aBuilder,
+    mozilla::wr::IpcResourceUpdateQueue& aResources,
+    const mozilla::layers::StackingContextHelper& aSc,
+    mozilla::layers::RenderRootStateManager* aManager, nsIFrame* aFrame,
+    StyleAppearance aAppearance, const nsRect& aRect) {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return ThemeCocoa::CreateWebRenderCommandsForWidget(
+        aBuilder, aResources, aSc, aManager, aFrame, aAppearance, aRect);
+  }
+
+  // This list needs to stay consistent with the list in DrawWidgetBackground.
+  // For every switch case in DrawWidgetBackground, there are three choices:
+  //  - If the case in DrawWidgetBackground draws nothing for the given widget
+  //    type, then don't list it here. We will hit the "default: return true;"
+  //    case.
+  //  - If the case in DrawWidgetBackground draws something simple for the given
+  //    widget type, imitate that drawing using WebRender commands.
+  //  - If the case in DrawWidgetBackground draws something complicated for the
+  //    given widget type, return false here.
+  switch (aAppearance) {
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Radio:
+    case StyleAppearance::Button:
+    case StyleAppearance::MozMacHelpButton:
+    case StyleAppearance::MozMacDisclosureButtonOpen:
+    case StyleAppearance::MozMacDisclosureButtonClosed:
+    case StyleAppearance::Spinner:
+    case StyleAppearance::SpinnerUpbutton:
+    case StyleAppearance::SpinnerDownbutton:
+    case StyleAppearance::Toolbarbutton:
+    case StyleAppearance::Separator:
+    case StyleAppearance::Toolbar:
+    case StyleAppearance::MozWindowTitlebar:
+    case StyleAppearance::Statusbar:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::MozMenulistArrowButton:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Searchfield:
+    case StyleAppearance::ProgressBar:
+    case StyleAppearance::Meter:
+    case StyleAppearance::Treeheadercell:
+    case StyleAppearance::Treetwisty:
+    case StyleAppearance::Treetwistyopen:
+    case StyleAppearance::Treeitem:
+    case StyleAppearance::Treeview:
+    case StyleAppearance::Range:
+      return false;
+
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Tab:
+    case StyleAppearance::Tabpanels:
+      return false;
+
+    default:
+      return true;
+  }
+}
+
+LayoutDeviceIntMargin nsNativeThemeCocoa::DirectionAwareMargin(
+    const LayoutDeviceIntMargin& aMargin, nsIFrame* aFrame) {
+  // Assuming aMargin was originally specified for a horizontal LTR context,
+  // reinterpret the values as logical, and then map to physical coords
+  // according to aFrame's actual writing mode.
+  WritingMode wm = aFrame->GetWritingMode();
+  nsMargin m = LogicalMargin(wm, aMargin.top, aMargin.right, aMargin.bottom,
+                             aMargin.left)
+                   .GetPhysicalMargin(wm);
+  return LayoutDeviceIntMargin(m.top, m.right, m.bottom, m.left);
+}
+
+static const LayoutDeviceIntMargin kAquaDropdownBorder(1, 22, 2, 5);
+static const LayoutDeviceIntMargin kAquaComboboxBorder(3, 20, 3, 4);
+static const LayoutDeviceIntMargin kAquaSearchfieldBorder(3, 5, 2, 19);
+static const LayoutDeviceIntMargin kAquaSearchfieldBorderBigSur(5, 5, 4, 26);
+
+LayoutDeviceIntMargin nsNativeThemeCocoa::GetWidgetBorder(
+    nsDeviceContext* aContext, nsIFrame* aFrame, StyleAppearance aAppearance) {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return Theme::GetWidgetBorder(aContext, aFrame, aAppearance);
+  }
+
+  LayoutDeviceIntMargin result;
+
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+  switch (aAppearance) {
+    case StyleAppearance::Button: {
+      if (IsButtonTypeMenu(aFrame)) {
+        result = DirectionAwareMargin(kAquaDropdownBorder, aFrame);
+      } else {
+        result =
+            DirectionAwareMargin(LayoutDeviceIntMargin(1, 7, 3, 7), aFrame);
+      }
+      break;
+    }
+
+    case StyleAppearance::Toolbarbutton: {
+      result = DirectionAwareMargin(LayoutDeviceIntMargin(1, 4, 1, 4), aFrame);
+      break;
+    }
+
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Radio: {
+      // nsCheckboxRadioFrame::GetIntrinsicWidth and
+      // nsCheckboxRadioFrame::GetIntrinsicHeight assume a border width of 2px.
+      result.SizeTo(2, 2, 2, 2);
+      break;
+    }
+
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::MozMenulistArrowButton:
+      result = DirectionAwareMargin(kAquaDropdownBorder, aFrame);
+      break;
+
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield: {
+      SInt32 frameOutset = 0;
+      ::GetThemeMetric(kThemeMetricEditTextFrameOutset, &frameOutset);
+
+      SInt32 textPadding = 0;
+      ::GetThemeMetric(kThemeMetricEditTextWhitespace, &textPadding);
+
+      frameOutset += textPadding;
+
+      result.SizeTo(frameOutset, frameOutset, frameOutset, frameOutset);
+      break;
+    }
+
+    case StyleAppearance::Textarea:
+      result.SizeTo(1, 1, 1, 1);
+      break;
+
+    case StyleAppearance::Searchfield: {
+      auto border = nsCocoaFeatures::OnBigSurOrLater()
+                        ? kAquaSearchfieldBorderBigSur
+                        : kAquaSearchfieldBorder;
+      result = DirectionAwareMargin(border, aFrame);
+      break;
+    }
+
+    case StyleAppearance::Listbox: {
+      SInt32 frameOutset = 0;
+      ::GetThemeMetric(kThemeMetricListBoxFrameOutset, &frameOutset);
+      result.SizeTo(frameOutset, frameOutset, frameOutset, frameOutset);
+      break;
+    }
+
+    case StyleAppearance::Statusbar:
+      result.SizeTo(1, 0, 0, 0);
+      break;
+
+    default:
+      break;
+  }
+
+  if (IsHiDPIContext(aContext)) {
+    result = result + result;  // doubled
+  }
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(result);
+}
+
+// Return false here to indicate that CSS padding values should be used. There
+// is no reason to make a distinction between padding and border values, just
+// specify whatever values you want in GetWidgetBorder and only use this to
+// return true if you want to override CSS padding values.
+bool nsNativeThemeCocoa::GetWidgetPadding(nsDeviceContext* aContext,
+                                          nsIFrame* aFrame,
+                                          StyleAppearance aAppearance,
+                                          LayoutDeviceIntMargin* aResult) {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return Theme::GetWidgetPadding(aContext, aFrame, aAppearance, aResult);
+  }
+
+  // We don't want CSS padding being used for certain widgets.
+  // See bug 381639 for an example of why.
+  switch (aAppearance) {
+    // Radios and checkboxes return a fixed size in GetMinimumWidgetSize
+    // and have a meaningful baseline, so they can't have
+    // author-specified padding.
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Radio:
+      aResult->SizeTo(0, 0, 0, 0);
+      return true;
+
+    case StyleAppearance::Searchfield:
+      if (nsCocoaFeatures::OnBigSurOrLater()) {
+        return true;
+      }
+      break;
+
+    default:
+      break;
+  }
+  return false;
+}
+
+bool nsNativeThemeCocoa::GetWidgetOverflow(nsDeviceContext* aContext,
+                                           nsIFrame* aFrame,
+                                           StyleAppearance aAppearance,
+                                           nsRect* aOverflowRect) {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return ThemeCocoa::GetWidgetOverflow(aContext, aFrame, aAppearance,
+                                         aOverflowRect);
+  }
+  nsIntMargin overflow;
+  switch (aAppearance) {
+    case StyleAppearance::Button:
+    case StyleAppearance::MozMacDisclosureButtonOpen:
+    case StyleAppearance::MozMacDisclosureButtonClosed:
+    case StyleAppearance::MozMacHelpButton:
+    case StyleAppearance::Toolbarbutton:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Searchfield:
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::MozMenulistArrowButton:
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Radio:
+    case StyleAppearance::Tab: {
+      overflow.SizeTo(static_cast<int32_t>(kMaxFocusRingWidth),
+                      static_cast<int32_t>(kMaxFocusRingWidth),
+                      static_cast<int32_t>(kMaxFocusRingWidth),
+                      static_cast<int32_t>(kMaxFocusRingWidth));
+      break;
+    }
+    case StyleAppearance::ProgressBar: {
+      // Progress bars draw a 2 pixel white shadow under their progress
+      // indicators.
+      overflow.bottom = 2;
+      break;
+    }
+    case StyleAppearance::Meter: {
+      // Meter bars overflow their boxes by about 2 pixels.
+      overflow.SizeTo(2, 2, 2, 2);
+      break;
+    }
+    default:
+      break;
+  }
+
+  if (IsHiDPIContext(aContext)) {
+    // Double the number of device pixels.
+    overflow += overflow;
+  }
+
+  if (overflow != nsIntMargin()) {
+    int32_t p2a = aFrame->PresContext()->AppUnitsPerDevPixel();
+    aOverflowRect->Inflate(nsMargin(NSIntPixelsToAppUnits(overflow.top, p2a),
+                                    NSIntPixelsToAppUnits(overflow.right, p2a),
+                                    NSIntPixelsToAppUnits(overflow.bottom, p2a),
+                                    NSIntPixelsToAppUnits(overflow.left, p2a)));
+    return true;
+  }
+
+  return false;
+}
+
+LayoutDeviceIntSize nsNativeThemeCocoa::GetMinimumWidgetSize(
+    nsPresContext* aPresContext, nsIFrame* aFrame,
+    StyleAppearance aAppearance) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return ThemeCocoa::GetMinimumWidgetSize(aPresContext, aFrame, aAppearance);
+  }
+
+  LayoutDeviceIntSize result;
+  switch (aAppearance) {
+    case StyleAppearance::Button: {
+      result.SizeTo(pushButtonSettings.minimumSizes[miniControlSize].width,
+                    pushButtonSettings.naturalSizes[miniControlSize].height);
+      break;
+    }
+
+    case StyleAppearance::MozMacDisclosureButtonOpen:
+    case StyleAppearance::MozMacDisclosureButtonClosed: {
+      result.SizeTo(kDisclosureButtonSize.width, kDisclosureButtonSize.height);
+      break;
+    }
+
+    case StyleAppearance::MozMacHelpButton: {
+      result.SizeTo(kHelpButtonSize.width, kHelpButtonSize.height);
+      break;
+    }
+
+    case StyleAppearance::Toolbarbutton: {
+      result.SizeTo(0, toolbarButtonHeights[miniControlSize]);
+      break;
+    }
+
+    case StyleAppearance::Spinner:
+    case StyleAppearance::SpinnerUpbutton:
+    case StyleAppearance::SpinnerDownbutton: {
+      SInt32 buttonHeight = 0, buttonWidth = 0;
+      if (aFrame->GetContent()->IsXULElement()) {
+        ::GetThemeMetric(kThemeMetricLittleArrowsWidth, &buttonWidth);
+        ::GetThemeMetric(kThemeMetricLittleArrowsHeight, &buttonHeight);
+      } else {
+        NSSize size =
+            spinnerSettings
+                .minimumSizes[EnumSizeForCocoaSize(NSControlSizeMini)];
+        buttonWidth = size.width;
+        buttonHeight = size.height;
+        if (aAppearance != StyleAppearance::Spinner) {
+          // the buttons are half the height of the spinner
+          buttonHeight /= 2;
+        }
+      }
+      result.SizeTo(buttonWidth, buttonHeight);
+      break;
+    }
+
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton: {
+      SInt32 popupHeight = 0;
+      ::GetThemeMetric(kThemeMetricPopupButtonHeight, &popupHeight);
+      result.SizeTo(0, popupHeight);
+      break;
+    }
+
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Searchfield: {
+      // at minimum, we should be tall enough for 9pt text.
+      // I'm using hardcoded values here because the appearance manager
+      // values for the frame size are incorrect.
+      result.SizeTo(0, (2 + 2) /* top */ + 9 + (1 + 1) /* bottom */);
+      break;
+    }
+
+    case StyleAppearance::MozWindowButtonBox: {
+      NSSize size = WindowButtonsSize(aFrame);
+      result.SizeTo(size.width, size.height);
+      break;
+    }
+
+    case StyleAppearance::ProgressBar: {
+      SInt32 barHeight = 0;
+      ::GetThemeMetric(kThemeMetricNormalProgressBarThickness, &barHeight);
+      result.SizeTo(0, barHeight);
+      break;
+    }
+
+    case StyleAppearance::Separator: {
+      result.SizeTo(1, 1);
+      break;
+    }
+
+    case StyleAppearance::Treetwisty:
+    case StyleAppearance::Treetwistyopen: {
+      SInt32 twistyHeight = 0, twistyWidth = 0;
+      ::GetThemeMetric(kThemeMetricDisclosureButtonWidth, &twistyWidth);
+      ::GetThemeMetric(kThemeMetricDisclosureButtonHeight, &twistyHeight);
+      result.SizeTo(twistyWidth, twistyHeight);
+      break;
+    }
+
+    case StyleAppearance::Treeheader:
+    case StyleAppearance::Treeheadercell: {
+      SInt32 headerHeight = 0;
+      ::GetThemeMetric(kThemeMetricListHeaderHeight, &headerHeight);
+      result.SizeTo(0, headerHeight);
+      break;
+    }
+
+    case StyleAppearance::Tab: {
+      result.SizeTo(0, tabHeights[miniControlSize]);
+      break;
+    }
+
+    case StyleAppearance::RangeThumb: {
+      SInt32 width = 0;
+      SInt32 height = 0;
+      ::GetThemeMetric(kThemeMetricSliderMinThumbWidth, &width);
+      ::GetThemeMetric(kThemeMetricSliderMinThumbHeight, &height);
+      result.SizeTo(width, height);
+      break;
+    }
+
+    case StyleAppearance::MozMenulistArrowButton:
+      return ThemeCocoa::GetMinimumWidgetSize(aPresContext, aFrame,
+                                              aAppearance);
+
+    default:
+      break;
+  }
+
+  if (IsHiDPIContext(aPresContext->DeviceContext())) {
+    result = result * 2;
+  }
+
+  return result;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(LayoutDeviceIntSize());
+}
+
+NS_IMETHODIMP
+nsNativeThemeCocoa::WidgetStateChanged(nsIFrame* aFrame,
+                                       StyleAppearance aAppearance,
+                                       nsAtom* aAttribute, bool* aShouldRepaint,
+                                       const nsAttrValue* aOldValue) {
+  // Some widget types just never change state.
+  switch (aAppearance) {
+    case StyleAppearance::MozWindowTitlebar:
+    case StyleAppearance::Toolbox:
+    case StyleAppearance::Toolbar:
+    case StyleAppearance::Statusbar:
+    case StyleAppearance::Tooltip:
+    case StyleAppearance::Tabpanels:
+    case StyleAppearance::Tabpanel:
+    case StyleAppearance::Menupopup:
+    case StyleAppearance::Progresschunk:
+    case StyleAppearance::ProgressBar:
+    case StyleAppearance::Meter:
+    case StyleAppearance::Meterchunk:
+      *aShouldRepaint = false;
+      return NS_OK;
+    default:
+      break;
+  }
+
+  // XXXdwh Not sure what can really be done here.  Can at least guess for
+  // specific widgets that they're highly unlikely to have certain states.
+  // For example, a toolbar doesn't care about any states.
+  if (!aAttribute) {
+    // Hover/focus/active changed.  Always repaint.
+    *aShouldRepaint = true;
+  } else {
+    // Check the attribute to see if it's relevant.
+    // disabled, checked, dlgtype, default, etc.
+    *aShouldRepaint = false;
+    if (aAttribute == nsGkAtoms::disabled || aAttribute == nsGkAtoms::checked ||
+        aAttribute == nsGkAtoms::selected ||
+        aAttribute == nsGkAtoms::visuallyselected ||
+        aAttribute == nsGkAtoms::menuactive ||
+        aAttribute == nsGkAtoms::sortDirection ||
+        aAttribute == nsGkAtoms::focused || aAttribute == nsGkAtoms::_default ||
+        aAttribute == nsGkAtoms::open || aAttribute == nsGkAtoms::hover)
+      *aShouldRepaint = true;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNativeThemeCocoa::ThemeChanged() {
+  // This is unimplemented because we don't care if gecko changes its theme
+  // and macOS system appearance changes are handled by
+  // nsLookAndFeel::SystemWantsDarkTheme.
+  return NS_OK;
+}
+
+bool nsNativeThemeCocoa::ThemeSupportsWidget(nsPresContext* aPresContext,
+                                             nsIFrame* aFrame,
+                                             StyleAppearance aAppearance) {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return ThemeCocoa::ThemeSupportsWidget(aPresContext, aFrame, aAppearance);
+  }
+  // if this is a dropdown button in a combobox the answer is always no
+  if (aAppearance == StyleAppearance::MozMenulistArrowButton) {
+    nsIFrame* parentFrame = aFrame->GetParent();
+    if (parentFrame && parentFrame->IsComboboxControlFrame()) return false;
+  }
+
+  switch (aAppearance) {
+    // Combobox dropdowns don't support native theming in vertical mode.
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::MozMenulistArrowButton:
+      if (aFrame && aFrame->GetWritingMode().IsVertical()) {
+        return false;
+      }
+      [[fallthrough]];
+
+    case StyleAppearance::Listbox:
+    case StyleAppearance::MozWindowButtonBox:
+    case StyleAppearance::MozWindowTitlebar:
+    case StyleAppearance::Menupopup:
+    case StyleAppearance::Tooltip:
+
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Radio:
+    case StyleAppearance::MozMacHelpButton:
+    case StyleAppearance::MozMacDisclosureButtonOpen:
+    case StyleAppearance::MozMacDisclosureButtonClosed:
+    case StyleAppearance::MozMacUnifiedToolbarWindow:
+    case StyleAppearance::Button:
+    case StyleAppearance::Toolbarbutton:
+    case StyleAppearance::Spinner:
+    case StyleAppearance::SpinnerUpbutton:
+    case StyleAppearance::SpinnerDownbutton:
+    case StyleAppearance::Toolbar:
+    case StyleAppearance::Statusbar:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Searchfield:
+    case StyleAppearance::Toolbox:
+    case StyleAppearance::ProgressBar:
+    case StyleAppearance::Progresschunk:
+    case StyleAppearance::Meter:
+    case StyleAppearance::Meterchunk:
+    case StyleAppearance::Separator:
+
+    case StyleAppearance::Tabpanels:
+    case StyleAppearance::Tab:
+
+    case StyleAppearance::Treetwisty:
+    case StyleAppearance::Treetwistyopen:
+    case StyleAppearance::Treeview:
+    case StyleAppearance::Treeheader:
+    case StyleAppearance::Treeheadercell:
+    case StyleAppearance::Treeitem:
+    case StyleAppearance::Treeline:
+
+    case StyleAppearance::Range:
+      return !IsWidgetStyled(aPresContext, aFrame, aAppearance);
+
+    default:
+      break;
+  }
+
+  return false;
+}
+
+bool nsNativeThemeCocoa::WidgetIsContainer(StyleAppearance aAppearance) {
+  // flesh this out at some point
+  switch (aAppearance) {
+    case StyleAppearance::MozMenulistArrowButton:
+    case StyleAppearance::Radio:
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::ProgressBar:
+    case StyleAppearance::Meter:
+    case StyleAppearance::Range:
+    case StyleAppearance::MozMacHelpButton:
+    case StyleAppearance::MozMacDisclosureButtonOpen:
+    case StyleAppearance::MozMacDisclosureButtonClosed:
+      return false;
+    default:
+      break;
+  }
+  return true;
+}
+
+bool nsNativeThemeCocoa::ThemeDrawsFocusForWidget(nsIFrame*,
+                                                  StyleAppearance aAppearance) {
+  switch (aAppearance) {
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Searchfield:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Button:
+    case StyleAppearance::MozMacHelpButton:
+    case StyleAppearance::MozMacDisclosureButtonOpen:
+    case StyleAppearance::MozMacDisclosureButtonClosed:
+    case StyleAppearance::Radio:
+    case StyleAppearance::Range:
+    case StyleAppearance::Checkbox:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool nsNativeThemeCocoa::ThemeNeedsComboboxDropmarker() { return false; }
+
+bool nsNativeThemeCocoa::WidgetAppearanceDependsOnWindowFocus(
+    StyleAppearance aAppearance) {
+  switch (aAppearance) {
+    case StyleAppearance::Tabpanels:
+    case StyleAppearance::Menupopup:
+    case StyleAppearance::Tooltip:
+    case StyleAppearance::Spinner:
+    case StyleAppearance::SpinnerUpbutton:
+    case StyleAppearance::SpinnerDownbutton:
+    case StyleAppearance::Separator:
+    case StyleAppearance::Toolbox:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Treeview:
+    case StyleAppearance::Treeline:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Listbox:
+      return false;
+    default:
+      return true;
+  }
+}
+
+nsITheme::ThemeGeometryType nsNativeThemeCocoa::ThemeGeometryTypeForWidget(
+    nsIFrame* aFrame, StyleAppearance aAppearance) {
+  switch (aAppearance) {
+    case StyleAppearance::MozWindowTitlebar:
+      return eThemeGeometryTypeTitlebar;
+    case StyleAppearance::Toolbar:
+      return eThemeGeometryTypeToolbar;
+    case StyleAppearance::Toolbox:
+      return eThemeGeometryTypeToolbox;
+    case StyleAppearance::MozWindowButtonBox:
+      return eThemeGeometryTypeWindowButtons;
+    case StyleAppearance::Tooltip:
+      return eThemeGeometryTypeTooltip;
+    case StyleAppearance::Menupopup:
+      return eThemeGeometryTypeMenu;
+    default:
+      return eThemeGeometryTypeUnknown;
+  }
+}
+
+nsITheme::Transparency nsNativeThemeCocoa::GetWidgetTransparency(
+    nsIFrame* aFrame, StyleAppearance aAppearance) {
+  if (IsWidgetScrollbarPart(aAppearance)) {
+    return ThemeCocoa::GetWidgetTransparency(aFrame, aAppearance);
+  }
+
+  switch (aAppearance) {
+    case StyleAppearance::Menupopup:
+    case StyleAppearance::Tooltip:
+    case StyleAppearance::Toolbar:
+      return eTransparent;
+    case StyleAppearance::MozMacUnifiedToolbarWindow:
+      // We want these to be treated as opaque by Gecko. We ensure there's an
+      // appropriate OS-level clear color to make sure that's the case.
+      return eOpaque;
+    case StyleAppearance::Statusbar:
+      // Knowing that scrollbars and statusbars are opaque improves
+      // performance, because we create layers for them.
+      return eOpaque;
+
+    default:
+      return eUnknownTransparency;
+  }
+}
+
+already_AddRefed<widget::Theme> do_CreateNativeThemeDoNotUseDirectly() {
+  return do_AddRef(new nsNativeThemeCocoa());
+}
diff --git a/widget/cocoa/nsNativeThemeColors.h b/widget/cocoa/nsNativeThemeColors.h
new file mode 100644
index 0000000000..02ec96f51a
--- /dev/null
+++ b/widget/cocoa/nsNativeThemeColors.h
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsNativeThemeColors_h_
+#define nsNativeThemeColors_h_
+
+#import <Cocoa/Cocoa.h>
+
+#include "mozilla/ColorScheme.h"
+
+enum ColorName {
+  toolbarTopBorderGrey,
+  toolbarFillGrey,
+  toolbarBottomBorderGrey,
+};
+
+static const int sLionThemeColors[][2] = {
+    /* { active window, inactive window } */
+    // toolbar:
+    {0xD0, 0xF0},  // top separator line
+    {0xB2, 0xE1},  // fill color
+    {0x59, 0x87},  // bottom separator line
+};
+
+static const int sYosemiteThemeColors[][2] = {
+    /* { active window, inactive window } */
+    // toolbar:
+    {0xBD, 0xDF},  // top separator line
+    {0xD3, 0xF6},  // fill color
+    {0xB3, 0xD1},  // bottom separator line
+};
+
+inline int NativeGreyColorAsInt(ColorName name, BOOL isMain) {
+  return sYosemiteThemeColors[name][isMain ? 0 : 1];
+}
+
+inline float NativeGreyColorAsFloat(ColorName name, BOOL isMain) {
+  return NativeGreyColorAsInt(name, isMain) / 255.0f;
+}
+
+inline void DrawNativeGreyColorInRect(CGContextRef context, ColorName name,
+                                      CGRect rect, BOOL isMain) {
+  float grey = NativeGreyColorAsFloat(name, isMain);
+  CGContextSetRGBFillColor(context, grey, grey, grey, 1.0f);
+  CGContextFillRect(context, rect);
+}
+
+inline NSAppearance* NSAppearanceForColorScheme(mozilla::ColorScheme aScheme) {
+  NSAppearanceName appearanceName = aScheme == mozilla::ColorScheme::Light
+                                        ? NSAppearanceNameAqua
+                                        : NSAppearanceNameDarkAqua;
+  return [NSAppearance appearanceNamed:appearanceName];
+}
+
+#endif  // nsNativeThemeColors_h_
diff --git a/widget/cocoa/nsPIWidgetCocoa.idl b/widget/cocoa/nsPIWidgetCocoa.idl
new file mode 100644
index 0000000000..54aa0d5113
--- /dev/null
+++ b/widget/cocoa/nsPIWidgetCocoa.idl
@@ -0,0 +1,37 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIWidget;
+
+[ptr] native NSWindowPtr(NSWindow);
+
+//
+// nsPIWidgetCocoa
+//
+// A private interface (unfrozen, private to the widget implementation) that
+// gives us access to some extra features on a widget/window.
+//
+[uuid(f75ff69e-3a51-419e-bd29-042f804bc2ed)]
+interface nsPIWidgetCocoa : nsISupports
+{
+  void SendSetZLevelEvent();
+
+  // Find the displayed child sheet (if aShown) or a child sheet that
+  // wants to be displayed (if !aShown)
+  nsIWidget GetChildSheet(in boolean aShown);
+
+  // Get the parent widget (if any) StandardCreate() was called with.
+  nsIWidget GetRealParent();
+
+  // If the object implementing this interface is a sheet, this will return the
+  // native NSWindow it is attached to
+  readonly attribute NSWindowPtr sheetWindowParent;
+
+  // True if window is a sheet
+  readonly attribute boolean isSheet;
+
+}; // nsPIWidgetCocoa
diff --git a/widget/cocoa/nsPrintDialogX.h b/widget/cocoa/nsPrintDialogX.h
new file mode 100644
index 0000000000..9c4b55647b
--- /dev/null
+++ b/widget/cocoa/nsPrintDialogX.h
@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrintDialog_h_
+#define nsPrintDialog_h_
+
+#include "nsIPrintDialogService.h"
+#include "nsCOMPtr.h"
+#include "nsCocoaUtils.h"
+
+#import <Cocoa/Cocoa.h>
+
+class nsIPrintSettings;
+class nsIStringBundle;
+
+class nsPrintDialogServiceX final : public nsIPrintDialogService {
+  virtual ~nsPrintDialogServiceX();
+
+ public:
+  nsPrintDialogServiceX();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIPRINTDIALOGSERVICE
+};
+
+@interface PrintPanelAccessoryView : NSView {
+  nsIPrintSettings* mSettings;
+  nsIStringBundle* mPrintBundle;
+  NSButton* mPrintSelectionOnlyCheckbox;
+  NSButton* mShrinkToFitCheckbox;
+  NSButton* mPrintBGColorsCheckbox;
+  NSButton* mPrintBGImagesCheckbox;
+  NSPopUpButton* mHeaderLeftList;
+  NSPopUpButton* mHeaderCenterList;
+  NSPopUpButton* mHeaderRightList;
+  NSPopUpButton* mFooterLeftList;
+  NSPopUpButton* mFooterCenterList;
+  NSPopUpButton* mFooterRightList;
+}
+
+- (id)initWithSettings:(nsIPrintSettings*)aSettings
+         haveSelection:(bool)aHaveSelection;
+
+- (void)exportSettings;
+
+@end
+
+@interface PrintPanelAccessoryController
+    : NSViewController <NSPrintPanelAccessorizing>
+
+- (id)initWithSettings:(nsIPrintSettings*)aSettings
+         haveSelection:(bool)aHaveSelection;
+
+- (void)exportSettings;
+
+@end
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsPrintDialogServiceX, NS_IPRINTDIALOGSERVICE_IID)
+
+#endif  // nsPrintDialog_h_
diff --git a/widget/cocoa/nsPrintDialogX.mm b/widget/cocoa/nsPrintDialogX.mm
new file mode 100644
index 0000000000..5cad69d547
--- /dev/null
+++ b/widget/cocoa/nsPrintDialogX.mm
@@ -0,0 +1,636 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/gfx/PrintTargetCG.h"
+#include "mozilla/Preferences.h"
+
+#include "nsPrintDialogX.h"
+#include "nsIPrintSettings.h"
+#include "nsIPrintSettingsService.h"
+#include "nsPrintSettingsX.h"
+#include "nsCOMPtr.h"
+#include "nsQueryObject.h"
+#include "nsServiceManagerUtils.h"
+#include "nsIStringBundle.h"
+#include "nsCRT.h"
+
+#import <Cocoa/Cocoa.h>
+#include "nsObjCExceptions.h"
+
+using namespace mozilla;
+using mozilla::gfx::PrintTarget;
+
+NS_IMPL_ISUPPORTS(nsPrintDialogServiceX, nsIPrintDialogService)
+
+// Splits our single pages-per-sheet count for native NSPrintInfo:
+static void setPagesPerSheet(NSPrintInfo* aPrintInfo, int32_t aPPS) {
+  int32_t across, down;
+  // Assumes portrait - we'll swap if landscape.
+  switch (aPPS) {
+    case 2:
+      across = 1;
+      down = 2;
+      break;
+    case 4:
+      across = 2;
+      down = 2;
+      break;
+    case 6:
+      across = 2;
+      down = 3;
+      break;
+    case 9:
+      across = 3;
+      down = 3;
+      break;
+    case 16:
+      across = 4;
+      down = 4;
+      break;
+    default:
+      across = 1;
+      down = 1;
+      break;
+  }
+  if ([aPrintInfo orientation] == NSPaperOrientationLandscape) {
+    std::swap(across, down);
+  }
+
+  NSMutableDictionary* dict = [aPrintInfo dictionary];
+
+  [dict setObject:[NSNumber numberWithInt:across] forKey:@"NSPagesAcross"];
+  [dict setObject:[NSNumber numberWithInt:down] forKey:@"NSPagesDown"];
+}
+
+nsPrintDialogServiceX::nsPrintDialogServiceX() {}
+
+nsPrintDialogServiceX::~nsPrintDialogServiceX() {}
+
+NS_IMETHODIMP
+nsPrintDialogServiceX::Init() { return NS_OK; }
+
+NS_IMETHODIMP
+nsPrintDialogServiceX::ShowPrintDialog(mozIDOMWindowProxy* aParent,
+                                       bool aHaveSelection,
+                                       nsIPrintSettings* aSettings) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_ASSERT(aSettings, "aSettings must not be null");
+
+  RefPtr<nsPrintSettingsX> settingsX(do_QueryObject(aSettings));
+  if (!settingsX) {
+    return NS_ERROR_FAILURE;
+  }
+
+  NSPrintInfo* printInfo =
+      settingsX->CreateOrCopyPrintInfo(/* aWithScaling = */ true);
+  if (NS_WARN_IF(!printInfo)) {
+    return NS_ERROR_FAILURE;
+  }
+  [printInfo autorelease];
+
+  // Set the print job title
+  nsAutoString docName;
+  nsresult rv = aSettings->GetTitle(docName);
+  if (NS_SUCCEEDED(rv)) {
+    nsAutoString adjustedTitle;
+    PrintTarget::AdjustPrintJobNameForIPP(docName, adjustedTitle);
+    CFStringRef cfTitleString = CFStringCreateWithCharacters(
+        NULL, reinterpret_cast<const UniChar*>(adjustedTitle.BeginReading()),
+        adjustedTitle.Length());
+    if (cfTitleString) {
+      auto pmPrintSettings =
+          static_cast<PMPrintSettings>([printInfo PMPrintSettings]);
+      ::PMPrintSettingsSetJobName(pmPrintSettings, cfTitleString);
+      [printInfo updateFromPMPrintSettings];
+      CFRelease(cfTitleString);
+    }
+  }
+
+  // Temporarily set the pages-per-sheet count set in our print preview to
+  // pre-populate the system dialog with the same value:
+  int32_t pagesPerSheet;
+  aSettings->GetNumPagesPerSheet(&pagesPerSheet);
+  setPagesPerSheet(printInfo, pagesPerSheet);
+
+  // Put the print info into the current print operation, since that's where
+  // [panel runModal] will look for it. We create the view because otherwise
+  // we'll get unrelated warnings printed to the console.
+  NSView* tmpView = [[NSView alloc] init];
+  NSPrintOperation* printOperation =
+      [NSPrintOperation printOperationWithView:tmpView printInfo:printInfo];
+  [NSPrintOperation setCurrentOperation:printOperation];
+
+  NSPrintPanel* panel = [NSPrintPanel printPanel];
+  [panel setOptions:NSPrintPanelShowsCopies | NSPrintPanelShowsPageRange |
+                    NSPrintPanelShowsPaperSize | NSPrintPanelShowsOrientation |
+                    NSPrintPanelShowsScaling];
+  PrintPanelAccessoryController* viewController =
+      [[PrintPanelAccessoryController alloc] initWithSettings:aSettings
+                                                haveSelection:aHaveSelection];
+  [panel addAccessoryController:viewController];
+  [viewController release];
+
+  // Show the dialog.
+  nsCocoaUtils::PrepareForNativeAppModalDialog();
+  int button = [panel runModal];
+  nsCocoaUtils::CleanUpAfterNativeAppModalDialog();
+
+  // Retrieve a printInfo with the updated settings. (The NSPrintOperation
+  // operates on a copy, so the object we passed in will not have been
+  // modified.)
+  NSPrintInfo* result = [[NSPrintOperation currentOperation] printInfo];
+  if (!result) {
+    return NS_ERROR_FAILURE;
+  }
+
+  [NSPrintOperation setCurrentOperation:nil];
+  [tmpView release];
+
+  if (button != NSModalResponseOK) {
+    return NS_ERROR_ABORT;
+  }
+
+  // We handle pages-per-sheet internally and we want to prevent the macOS
+  // printing code from also applying the pages-per-sheet count. So we need
+  // to move the count off the NSPrintInfo and over to the nsIPrintSettings.
+  NSMutableDictionary* dict = [result dictionary];
+  auto pagesAcross = [[dict objectForKey:@"NSPagesAcross"] intValue];
+  auto pagesDown = [[dict objectForKey:@"NSPagesDown"] intValue];
+  [dict setObject:[NSNumber numberWithUnsignedInt:1] forKey:@"NSPagesAcross"];
+  [dict setObject:[NSNumber numberWithUnsignedInt:1] forKey:@"NSPagesDown"];
+  aSettings->SetNumPagesPerSheet(pagesAcross * pagesDown);
+
+  // Export settings.
+  [viewController exportSettings];
+
+  // Update our settings object based on the user's choices in the dialog.
+  // We tell settingsX to adopt this printInfo so that it will be used to run
+  // print job, so that any printer-specific custom settings from print dialog
+  // extension panels will be carried through.
+  settingsX->SetFromPrintInfo(result, /* aAdoptPrintInfo = */ true);
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsPrintDialogServiceX::ShowPageSetupDialog(mozIDOMWindowProxy* aParent,
+                                           nsIPrintSettings* aNSSettings) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  MOZ_ASSERT(aParent, "aParent must not be null");
+  MOZ_ASSERT(aNSSettings, "aSettings must not be null");
+  NS_ENSURE_TRUE(aNSSettings, NS_ERROR_FAILURE);
+
+  RefPtr<nsPrintSettingsX> settingsX(do_QueryObject(aNSSettings));
+  if (!settingsX) {
+    return NS_ERROR_FAILURE;
+  }
+
+  NSPrintInfo* printInfo =
+      settingsX->CreateOrCopyPrintInfo(/* aWithScaling = */ true);
+  if (NS_WARN_IF(!printInfo)) {
+    return NS_ERROR_FAILURE;
+  }
+  [printInfo autorelease];
+
+  NSPageLayout* pageLayout = [NSPageLayout pageLayout];
+  nsCocoaUtils::PrepareForNativeAppModalDialog();
+  int button = [pageLayout runModalWithPrintInfo:printInfo];
+  nsCocoaUtils::CleanUpAfterNativeAppModalDialog();
+
+  if (button == NSModalResponseOK) {
+    // The Page Setup dialog does not include non-standard settings that need to
+    // be preserved, separate from what the base printSettings object handles,
+    // so we do not need it to adopt the printInfo object here.
+    settingsX->SetFromPrintInfo(printInfo, /* aAdoptPrintInfo = */ false);
+    nsCOMPtr<nsIPrintSettingsService> printSettingsService =
+        do_GetService("@mozilla.org/gfx/printsettings-service;1");
+    if (printSettingsService &&
+        Preferences::GetBool("print.save_print_settings", false)) {
+      uint32_t flags = nsIPrintSettings::kInitSavePaperSize |
+                       nsIPrintSettings::kInitSaveOrientation |
+                       nsIPrintSettings::kInitSaveScaling;
+      printSettingsService->MaybeSavePrintSettingsToPrefs(aNSSettings, flags);
+    }
+    return NS_OK;
+  }
+  return NS_ERROR_ABORT;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+// Accessory view
+
+@interface PrintPanelAccessoryView (Private)
+
+- (NSString*)localizedString:(const char*)aKey;
+
+- (const char*)headerFooterStringForList:(NSPopUpButton*)aList;
+
+- (void)exportHeaderFooterSettings;
+
+- (void)initBundle;
+
+- (NSTextField*)label:(const char*)aLabel
+            withFrame:(NSRect)aRect
+            alignment:(NSTextAlignment)aAlignment;
+
+- (void)addLabel:(const char*)aLabel
+       withFrame:(NSRect)aRect
+       alignment:(NSTextAlignment)aAlignment;
+
+- (void)addLabel:(const char*)aLabel withFrame:(NSRect)aRect;
+
+- (void)addCenteredLabel:(const char*)aLabel withFrame:(NSRect)aRect;
+
+- (NSButton*)checkboxWithLabel:(const char*)aLabel andFrame:(NSRect)aRect;
+
+- (NSPopUpButton*)headerFooterItemListWithFrame:(NSRect)aRect
+                                   selectedItem:
+                                       (const nsAString&)aCurrentString;
+
+- (void)addOptionsSection:(bool)aHaveSelection;
+
+- (void)addAppearanceSection;
+
+- (void)addHeaderFooterSection;
+
+- (NSString*)summaryValueForCheckbox:(NSButton*)aCheckbox;
+
+- (NSString*)headerSummaryValue;
+
+- (NSString*)footerSummaryValue;
+
+@end
+
+static const char sHeaderFooterTags[][4] = {"", "&T", "&U", "&D", "&P", "&PT"};
+
+@implementation PrintPanelAccessoryView
+
+// Public methods
+
+- (id)initWithSettings:(nsIPrintSettings*)aSettings
+         haveSelection:(bool)aHaveSelection {
+  [super initWithFrame:NSMakeRect(0, 0, 540, 185)];
+
+  mSettings = aSettings;
+  [self initBundle];
+  [self addOptionsSection:aHaveSelection];
+  [self addAppearanceSection];
+  [self addHeaderFooterSection];
+
+  return self;
+}
+
+- (void)exportSettings {
+  mSettings->SetPrintSelectionOnly([mPrintSelectionOnlyCheckbox state] ==
+                                   NSControlStateValueOn);
+  mSettings->SetShrinkToFit([mShrinkToFitCheckbox state] ==
+                            NSControlStateValueOn);
+  mSettings->SetPrintBGColors([mPrintBGColorsCheckbox state] ==
+                              NSControlStateValueOn);
+  mSettings->SetPrintBGImages([mPrintBGImagesCheckbox state] ==
+                              NSControlStateValueOn);
+
+  [self exportHeaderFooterSettings];
+}
+
+- (void)dealloc {
+  NS_IF_RELEASE(mPrintBundle);
+  [super dealloc];
+}
+
+// Localization
+
+- (void)initBundle {
+  nsCOMPtr<nsIStringBundleService> bundleSvc =
+      do_GetService(NS_STRINGBUNDLE_CONTRACTID);
+  bundleSvc->CreateBundle("chrome://global/locale/printdialog.properties",
+                          &mPrintBundle);
+}
+
+- (NSString*)localizedString:(const char*)aKey {
+  if (!mPrintBundle) return @"";
+
+  nsAutoString intlString;
+  mPrintBundle->GetStringFromName(aKey, intlString);
+  NSMutableString* s = [NSMutableString
+      stringWithUTF8String:NS_ConvertUTF16toUTF8(intlString).get()];
+
+  // Remove all underscores (they're used in the GTK dialog for accesskeys).
+  [s replaceOccurrencesOfString:@"_"
+                     withString:@""
+                        options:0
+                          range:NSMakeRange(0, [s length])];
+  return s;
+}
+
+// Widget helpers
+
+- (NSTextField*)label:(const char*)aLabel
+            withFrame:(NSRect)aRect
+            alignment:(NSTextAlignment)aAlignment {
+  NSTextField* label = [[[NSTextField alloc] initWithFrame:aRect] autorelease];
+  [label setStringValue:[self localizedString:aLabel]];
+  [label setEditable:NO];
+  [label setSelectable:NO];
+  [label setBezeled:NO];
+  [label setBordered:NO];
+  [label setDrawsBackground:NO];
+  [label setFont:[NSFont systemFontOfSize:[NSFont systemFontSize]]];
+  [label setAlignment:aAlignment];
+  return label;
+}
+
+- (void)addLabel:(const char*)aLabel
+       withFrame:(NSRect)aRect
+       alignment:(NSTextAlignment)aAlignment {
+  NSTextField* label = [self label:aLabel withFrame:aRect alignment:aAlignment];
+  [self addSubview:label];
+}
+
+- (void)addLabel:(const char*)aLabel withFrame:(NSRect)aRect {
+  [self addLabel:aLabel withFrame:aRect alignment:NSTextAlignmentRight];
+}
+
+- (void)addCenteredLabel:(const char*)aLabel withFrame:(NSRect)aRect {
+  [self addLabel:aLabel withFrame:aRect alignment:NSTextAlignmentCenter];
+}
+
+- (NSButton*)checkboxWithLabel:(const char*)aLabel andFrame:(NSRect)aRect {
+  aRect.origin.y += 4.0f;
+  NSButton* checkbox = [[[NSButton alloc] initWithFrame:aRect] autorelease];
+  [checkbox setButtonType:NSButtonTypeSwitch];
+  [checkbox setTitle:[self localizedString:aLabel]];
+  [checkbox setFont:[NSFont systemFontOfSize:[NSFont systemFontSize]]];
+  [checkbox sizeToFit];
+  return checkbox;
+}
+
+- (NSPopUpButton*)headerFooterItemListWithFrame:(NSRect)aRect
+                                   selectedItem:
+                                       (const nsAString&)aCurrentString {
+  NSPopUpButton* list = [[[NSPopUpButton alloc] initWithFrame:aRect
+                                                    pullsDown:NO] autorelease];
+  [list setFont:[NSFont systemFontOfSize:[NSFont smallSystemFontSize]]];
+  [[list cell] setControlSize:NSControlSizeSmall];
+  NSArray* items = [NSArray
+      arrayWithObjects:[self localizedString:"headerFooterBlank"],
+                       [self localizedString:"headerFooterTitle"],
+                       [self localizedString:"headerFooterURL"],
+                       [self localizedString:"headerFooterDate"],
+                       [self localizedString:"headerFooterPage"],
+                       [self localizedString:"headerFooterPageTotal"], nil];
+  [list addItemsWithTitles:items];
+
+  NS_ConvertUTF16toUTF8 currentStringUTF8(aCurrentString);
+  for (unsigned int i = 0; i < ArrayLength(sHeaderFooterTags); i++) {
+    if (!strcmp(currentStringUTF8.get(), sHeaderFooterTags[i])) {
+      [list selectItemAtIndex:i];
+      break;
+    }
+  }
+
+  return list;
+}
+
+// Build sections
+
+- (void)addOptionsSection:(bool)aHaveSelection {
+  // Title
+  [self addLabel:"optionsTitleMac" withFrame:NSMakeRect(0, 155, 151, 22)];
+
+  // "Print Selection Only"
+  mPrintSelectionOnlyCheckbox =
+      [self checkboxWithLabel:"selectionOnly"
+                     andFrame:NSMakeRect(156, 155, 0, 0)];
+  [mPrintSelectionOnlyCheckbox setEnabled:aHaveSelection];
+
+  if (mSettings->GetPrintSelectionOnly()) {
+    [mPrintSelectionOnlyCheckbox setState:NSControlStateValueOn];
+  }
+
+  [self addSubview:mPrintSelectionOnlyCheckbox];
+
+  // "Shrink To Fit"
+  mShrinkToFitCheckbox = [self checkboxWithLabel:"shrinkToFit"
+                                        andFrame:NSMakeRect(156, 133, 0, 0)];
+
+  bool shrinkToFit;
+  mSettings->GetShrinkToFit(&shrinkToFit);
+  [mShrinkToFitCheckbox
+      setState:(shrinkToFit ? NSControlStateValueOn : NSControlStateValueOff)];
+
+  [self addSubview:mShrinkToFitCheckbox];
+}
+
+- (void)addAppearanceSection {
+  // Title
+  [self addLabel:"appearanceTitleMac" withFrame:NSMakeRect(0, 103, 151, 22)];
+
+  // "Print Background Colors"
+  mPrintBGColorsCheckbox = [self checkboxWithLabel:"printBGColors"
+                                          andFrame:NSMakeRect(156, 103, 0, 0)];
+
+  bool geckoBool = mSettings->GetPrintBGColors();
+  [mPrintBGColorsCheckbox
+      setState:(geckoBool ? NSControlStateValueOn : NSControlStateValueOff)];
+
+  [self addSubview:mPrintBGColorsCheckbox];
+
+  // "Print Background Images"
+  mPrintBGImagesCheckbox = [self checkboxWithLabel:"printBGImages"
+                                          andFrame:NSMakeRect(156, 81, 0, 0)];
+
+  geckoBool = mSettings->GetPrintBGImages();
+  [mPrintBGImagesCheckbox
+      setState:(geckoBool ? NSControlStateValueOn : NSControlStateValueOff)];
+
+  [self addSubview:mPrintBGImagesCheckbox];
+}
+
+- (void)addHeaderFooterSection {
+  // Labels
+  [self addLabel:"pageHeadersTitleMac" withFrame:NSMakeRect(0, 44, 151, 22)];
+  [self addLabel:"pageFootersTitleMac" withFrame:NSMakeRect(0, 0, 151, 22)];
+  [self addCenteredLabel:"left" withFrame:NSMakeRect(156, 22, 100, 22)];
+  [self addCenteredLabel:"center" withFrame:NSMakeRect(256, 22, 100, 22)];
+  [self addCenteredLabel:"right" withFrame:NSMakeRect(356, 22, 100, 22)];
+
+  // Lists
+  nsString sel;
+
+  mSettings->GetHeaderStrLeft(sel);
+  mHeaderLeftList =
+      [self headerFooterItemListWithFrame:NSMakeRect(156, 44, 100, 22)
+                             selectedItem:sel];
+  [self addSubview:mHeaderLeftList];
+
+  mSettings->GetHeaderStrCenter(sel);
+  mHeaderCenterList =
+      [self headerFooterItemListWithFrame:NSMakeRect(256, 44, 100, 22)
+                             selectedItem:sel];
+  [self addSubview:mHeaderCenterList];
+
+  mSettings->GetHeaderStrRight(sel);
+  mHeaderRightList =
+      [self headerFooterItemListWithFrame:NSMakeRect(356, 44, 100, 22)
+                             selectedItem:sel];
+  [self addSubview:mHeaderRightList];
+
+  mSettings->GetFooterStrLeft(sel);
+  mFooterLeftList =
+      [self headerFooterItemListWithFrame:NSMakeRect(156, 0, 100, 22)
+                             selectedItem:sel];
+  [self addSubview:mFooterLeftList];
+
+  mSettings->GetFooterStrCenter(sel);
+  mFooterCenterList =
+      [self headerFooterItemListWithFrame:NSMakeRect(256, 0, 100, 22)
+                             selectedItem:sel];
+  [self addSubview:mFooterCenterList];
+
+  mSettings->GetFooterStrRight(sel);
+  mFooterRightList =
+      [self headerFooterItemListWithFrame:NSMakeRect(356, 0, 100, 22)
+                             selectedItem:sel];
+  [self addSubview:mFooterRightList];
+}
+
+// Export settings
+
+- (const char*)headerFooterStringForList:(NSPopUpButton*)aList {
+  NSInteger index = [aList indexOfSelectedItem];
+  NS_ASSERTION(index < NSInteger(ArrayLength(sHeaderFooterTags)),
+               "Index of dropdown is higher than expected!");
+  return sHeaderFooterTags[index];
+}
+
+- (void)exportHeaderFooterSettings {
+  const char* headerFooterStr;
+  headerFooterStr = [self headerFooterStringForList:mHeaderLeftList];
+  mSettings->SetHeaderStrLeft(NS_ConvertUTF8toUTF16(headerFooterStr));
+
+  headerFooterStr = [self headerFooterStringForList:mHeaderCenterList];
+  mSettings->SetHeaderStrCenter(NS_ConvertUTF8toUTF16(headerFooterStr));
+
+  headerFooterStr = [self headerFooterStringForList:mHeaderRightList];
+  mSettings->SetHeaderStrRight(NS_ConvertUTF8toUTF16(headerFooterStr));
+
+  headerFooterStr = [self headerFooterStringForList:mFooterLeftList];
+  mSettings->SetFooterStrLeft(NS_ConvertUTF8toUTF16(headerFooterStr));
+
+  headerFooterStr = [self headerFooterStringForList:mFooterCenterList];
+  mSettings->SetFooterStrCenter(NS_ConvertUTF8toUTF16(headerFooterStr));
+
+  headerFooterStr = [self headerFooterStringForList:mFooterRightList];
+  mSettings->SetFooterStrRight(NS_ConvertUTF8toUTF16(headerFooterStr));
+}
+
+// Summary
+
+- (NSString*)summaryValueForCheckbox:(NSButton*)aCheckbox {
+  if (![aCheckbox isEnabled]) return [self localizedString:"summaryNAValue"];
+
+  return [aCheckbox state] == NSControlStateValueOn
+             ? [self localizedString:"summaryOnValue"]
+             : [self localizedString:"summaryOffValue"];
+}
+
+- (NSString*)headerSummaryValue {
+  return [[mHeaderLeftList titleOfSelectedItem]
+      stringByAppendingString:
+          [@", "
+              stringByAppendingString:
+                  [[mHeaderCenterList titleOfSelectedItem]
+                      stringByAppendingString:
+                          [@", " stringByAppendingString:
+                                     [mHeaderRightList titleOfSelectedItem]]]]];
+}
+
+- (NSString*)footerSummaryValue {
+  return [[mFooterLeftList titleOfSelectedItem]
+      stringByAppendingString:
+          [@", "
+              stringByAppendingString:
+                  [[mFooterCenterList titleOfSelectedItem]
+                      stringByAppendingString:
+                          [@", " stringByAppendingString:
+                                     [mFooterRightList titleOfSelectedItem]]]]];
+}
+
+- (NSArray*)localizedSummaryItems {
+  return [NSArray
+      arrayWithObjects:
+          [NSDictionary
+              dictionaryWithObjectsAndKeys:
+                  [self localizedString:"summarySelectionOnlyTitle"],
+                  NSPrintPanelAccessorySummaryItemNameKey,
+                  [self summaryValueForCheckbox:mPrintSelectionOnlyCheckbox],
+                  NSPrintPanelAccessorySummaryItemDescriptionKey, nil],
+          [NSDictionary dictionaryWithObjectsAndKeys:
+                            [self localizedString:"summaryShrinkToFitTitle"],
+                            NSPrintPanelAccessorySummaryItemNameKey,
+                            [self summaryValueForCheckbox:mShrinkToFitCheckbox],
+                            NSPrintPanelAccessorySummaryItemDescriptionKey,
+                            nil],
+          [NSDictionary
+              dictionaryWithObjectsAndKeys:
+                  [self localizedString:"summaryPrintBGColorsTitle"],
+                  NSPrintPanelAccessorySummaryItemNameKey,
+                  [self summaryValueForCheckbox:mPrintBGColorsCheckbox],
+                  NSPrintPanelAccessorySummaryItemDescriptionKey, nil],
+          [NSDictionary
+              dictionaryWithObjectsAndKeys:
+                  [self localizedString:"summaryPrintBGImagesTitle"],
+                  NSPrintPanelAccessorySummaryItemNameKey,
+                  [self summaryValueForCheckbox:mPrintBGImagesCheckbox],
+                  NSPrintPanelAccessorySummaryItemDescriptionKey, nil],
+          [NSDictionary dictionaryWithObjectsAndKeys:
+                            [self localizedString:"summaryHeaderTitle"],
+                            NSPrintPanelAccessorySummaryItemNameKey,
+                            [self headerSummaryValue],
+                            NSPrintPanelAccessorySummaryItemDescriptionKey,
+                            nil],
+          [NSDictionary dictionaryWithObjectsAndKeys:
+                            [self localizedString:"summaryFooterTitle"],
+                            NSPrintPanelAccessorySummaryItemNameKey,
+                            [self footerSummaryValue],
+                            NSPrintPanelAccessorySummaryItemDescriptionKey,
+                            nil],
+          nil];
+}
+
+@end
+
+// Accessory controller
+
+@implementation PrintPanelAccessoryController
+
+- (id)initWithSettings:(nsIPrintSettings*)aSettings
+         haveSelection:(bool)aHaveSelection {
+  [super initWithNibName:nil bundle:nil];
+
+  NSView* accView =
+      [[PrintPanelAccessoryView alloc] initWithSettings:aSettings
+                                          haveSelection:aHaveSelection];
+  [self setView:accView];
+  [accView release];
+  return self;
+}
+
+- (void)exportSettings {
+  return [(PrintPanelAccessoryView*)[self view] exportSettings];
+}
+
+- (NSArray*)localizedSummaryItems {
+  return [(PrintPanelAccessoryView*)[self view] localizedSummaryItems];
+}
+
+@end
diff --git a/widget/cocoa/nsPrintSettingsServiceX.h b/widget/cocoa/nsPrintSettingsServiceX.h
new file mode 100644
index 0000000000..e6e6bff2b9
--- /dev/null
+++ b/widget/cocoa/nsPrintSettingsServiceX.h
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrintSettingsServiceX_h
+#define nsPrintSettingsServiceX_h
+
+#include "nsPrintSettingsService.h"
+
+namespace mozilla {
+namespace embedding {
+class PrintData;
+}  // namespace embedding
+}  // namespace mozilla
+
+class nsPrintSettingsServiceX final : public nsPrintSettingsService {
+ public:
+  nsPrintSettingsServiceX() {}
+
+  NS_IMETHODIMP SerializeToPrintData(
+      nsIPrintSettings* aSettings,
+      mozilla::embedding::PrintData* data) override;
+
+  NS_IMETHODIMP DeserializeToPrintSettings(
+      const mozilla::embedding::PrintData& data,
+      nsIPrintSettings* settings) override;
+
+ protected:
+  nsresult _CreatePrintSettings(nsIPrintSettings** _retval) override;
+};
+
+#endif  // nsPrintSettingsServiceX_h
diff --git a/widget/cocoa/nsPrintSettingsServiceX.mm b/widget/cocoa/nsPrintSettingsServiceX.mm
new file mode 100644
index 0000000000..d2cb4486af
--- /dev/null
+++ b/widget/cocoa/nsPrintSettingsServiceX.mm
@@ -0,0 +1,78 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrintSettingsServiceX.h"
+
+#include "mozilla/embedding/PPrintingTypes.h"
+#include "nsCOMPtr.h"
+#include "nsQueryObject.h"
+#include "nsPrintSettingsX.h"
+#include "nsCocoaUtils.h"
+
+using namespace mozilla::embedding;
+
+NS_IMETHODIMP
+nsPrintSettingsServiceX::SerializeToPrintData(nsIPrintSettings* aSettings,
+                                              PrintData* data) {
+  nsresult rv = nsPrintSettingsService::SerializeToPrintData(aSettings, data);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  RefPtr<nsPrintSettingsX> settingsX(do_QueryObject(aSettings));
+  if (NS_WARN_IF(!settingsX)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  settingsX->GetDisposition(data->disposition());
+  settingsX->GetDestination(&data->destination());
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsServiceX::DeserializeToPrintSettings(
+    const PrintData& data, nsIPrintSettings* settings) {
+  nsresult rv =
+      nsPrintSettingsService::DeserializeToPrintSettings(data, settings);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  RefPtr<nsPrintSettingsX> settingsX(do_QueryObject(settings));
+  if (NS_WARN_IF(!settingsX)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  settingsX->SetDisposition(data.disposition());
+  settingsX->SetDestination(data.destination());
+
+  return NS_OK;
+}
+
+nsresult nsPrintSettingsServiceX::_CreatePrintSettings(
+    nsIPrintSettings** _retval) {
+  nsresult rv;
+  *_retval = nullptr;
+
+  nsPrintSettingsX* printSettings =
+      new nsPrintSettingsX;  // does not initially ref count
+  NS_ENSURE_TRUE(printSettings, NS_ERROR_OUT_OF_MEMORY);
+  NS_ADDREF(*_retval = printSettings);
+
+  rv = printSettings->Init();
+  if (NS_FAILED(rv)) {
+    NS_RELEASE(*_retval);
+    return rv;
+  }
+
+  auto globalPrintSettings = nsIPrintSettings::kGlobalSettings;
+
+  // XXX Why is Mac special? Why are we copying global print settings here?
+  // nsPrintSettingsService::InitPrintSettingsFromPrefs already gets the few
+  // global defaults that we want, doesn't it?
+  InitPrintSettingsFromPrefs(*_retval, false, globalPrintSettings);
+  return rv;
+}
diff --git a/widget/cocoa/nsPrintSettingsX.h b/widget/cocoa/nsPrintSettingsX.h
new file mode 100644
index 0000000000..e771df25b0
--- /dev/null
+++ b/widget/cocoa/nsPrintSettingsX.h
@@ -0,0 +1,106 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrintSettingsX_h_
+#define nsPrintSettingsX_h_
+
+#include "nsPrintSettingsImpl.h"
+#import <Cocoa/Cocoa.h>
+
+// clang-format off
+#define NS_PRINTSETTINGSX_IID                        \
+  {                                                  \
+    0x0DF2FDBD, 0x906D, 0x4726, {                    \
+      0x9E, 0x4D, 0xCF, 0xE0, 0x87, 0x8D, 0x70, 0x7C \
+    }                                                \
+  }
+// clang-format on
+
+class nsPrintSettingsX : public nsPrintSettings {
+ public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_PRINTSETTINGSX_IID)
+  NS_DECL_ISUPPORTS_INHERITED
+
+  nsPrintSettingsX();
+  explicit nsPrintSettingsX(const PrintSettingsInitializer& aSettings);
+
+  nsresult Init() { return NS_OK; }
+
+  void SetDestination(uint16_t aDestination) { mDestination = aDestination; }
+  void GetDestination(uint16_t* aDestination) { *aDestination = mDestination; }
+
+  void SetDisposition(const nsString& aDisposition) {
+    mDisposition = aDisposition;
+  }
+  void GetDisposition(nsString& aDisposition) { aDisposition = mDisposition; }
+
+  // Get a Cocoa NSPrintInfo that is configured with our current settings.
+  // This follows Create semantics, so the caller is responsible to release
+  // the returned object when no longer required.
+  //
+  // Pass true for aWithScaling to have the print scaling factor included in
+  // the returned printInfo. Normally we pass false, as scaling is handled
+  // by Gecko and we don't want the Cocoa print system to impose scaling again
+  // on the output, but if we're retrieving the info in order to populate the
+  // system print UI, then we do want to know about it.
+  NSPrintInfo* CreateOrCopyPrintInfo(bool aWithScaling = false);
+
+  // Update our internal settings to reflect the properties of the given
+  // NSPrintInfo.
+  //
+  // If aAdoptPrintInfo is set, the given NSPrintInfo will be retained and
+  // returned by subsequent CreateOrCopyPrintInfo calls, which is required
+  // for custom settings from the OS print dialog to be passed through to
+  // print jobs. However, this means that subsequent changes to print settings
+  // via the generic nsPrintSettings methods will NOT be reflected in the
+  // resulting NSPrintInfo.
+  void SetFromPrintInfo(NSPrintInfo* aPrintInfo, bool aAdoptPrintInfo);
+
+ protected:
+  virtual ~nsPrintSettingsX() {
+    if (mSystemPrintInfo) {
+      [mSystemPrintInfo release];
+    }
+  };
+
+  nsPrintSettingsX& operator=(const nsPrintSettingsX& rhs);
+
+  nsresult _Clone(nsIPrintSettings** _retval) override;
+  nsresult _Assign(nsIPrintSettings* aPS) override;
+
+  int GetCocoaUnit(int16_t aGeckoUnit);
+
+  double PaperSizeFromCocoaPoints(double aPointsValue) {
+    return aPointsValue *
+           (mPaperSizeUnit == kPaperSizeInches ? 1.0 / 72.0 : 25.4 / 72.0);
+  }
+
+  double CocoaPointsFromPaperSize(double aSizeUnitValue) {
+    return aSizeUnitValue *
+           (mPaperSizeUnit == kPaperSizeInches ? 72.0 : 72.0 / 25.4);
+  }
+
+  // Needed to correctly track the various job dispositions (spool, preview,
+  // save to file) that the user can choose via the system print dialog.
+  // Unfortunately it seems to be necessary to set both the Cocoa "job
+  // disposition" and the PrintManager "destination type" in order for all the
+  // various workflows such as "Save to Web Receipts" to work.
+  nsString mDisposition;
+  uint16_t mDestination;
+
+  // If the user has used the system print UI, we retain a reference to its
+  // printInfo because it may contain settings that we don't know how to handle
+  // and that will be lost if we round-trip through nsPrintSettings fields.
+  // We'll use this printInfo if asked to run a print job.
+  //
+  // This "wrapped" printInfo is NOT serialized or copied when printSettings
+  // objects are passed around; it is used only by the settings object to which
+  // it was originally passed.
+  NSPrintInfo* mSystemPrintInfo = nullptr;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsPrintSettingsX, NS_PRINTSETTINGSX_IID)
+
+#endif  // nsPrintSettingsX_h_
diff --git a/widget/cocoa/nsPrintSettingsX.mm b/widget/cocoa/nsPrintSettingsX.mm
new file mode 100644
index 0000000000..26c5ca9c37
--- /dev/null
+++ b/widget/cocoa/nsPrintSettingsX.mm
@@ -0,0 +1,372 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrintSettingsX.h"
+#include "nsObjCExceptions.h"
+
+#include "plbase64.h"
+
+#include "nsCocoaUtils.h"
+#include "nsXULAppAPI.h"
+
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_print.h"
+#include "nsPrinterCUPS.h"
+
+using namespace mozilla;
+
+NS_IMPL_ISUPPORTS_INHERITED(nsPrintSettingsX, nsPrintSettings, nsPrintSettingsX)
+
+nsPrintSettingsX::nsPrintSettingsX() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  mDestination = kPMDestinationInvalid;
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+already_AddRefed<nsIPrintSettings> CreatePlatformPrintSettings(
+    const PrintSettingsInitializer& aSettings) {
+  RefPtr<nsPrintSettings> settings = new nsPrintSettingsX();
+  settings->InitWithInitializer(aSettings);
+  settings->SetDefaultFileName();
+  return settings.forget();
+}
+
+nsPrintSettingsX& nsPrintSettingsX::operator=(const nsPrintSettingsX& rhs) {
+  if (this == &rhs) {
+    return *this;
+  }
+
+  nsPrintSettings::operator=(rhs);
+
+  mDestination = rhs.mDestination;
+  mDisposition = rhs.mDisposition;
+
+  // We don't copy mSystemPrintInfo here, so any copied printSettings will start
+  // out without a wrapped printInfo, just using our internal settings. The
+  // system printInfo is used *only* by the nsPrintSettingsX to which it was
+  // originally passed (when the user ran a system print UI dialog).
+
+  return *this;
+}
+
+nsresult nsPrintSettingsX::_Clone(nsIPrintSettings** _retval) {
+  NS_ENSURE_ARG_POINTER(_retval);
+  auto newSettings = MakeRefPtr<nsPrintSettingsX>();
+  *newSettings = *this;
+  newSettings.forget(_retval);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettingsX::_Assign(nsIPrintSettings* aPS) {
+  nsPrintSettingsX* printSettingsX = static_cast<nsPrintSettingsX*>(aPS);
+  if (!printSettingsX) {
+    return NS_ERROR_UNEXPECTED;
+  }
+  *this = *printSettingsX;
+  return NS_OK;
+}
+
+struct KnownMonochromeSetting {
+  const NSString* mName;
+  const NSString* mValue;
+};
+
+#define DECLARE_KNOWN_MONOCHROME_SETTING(key_, value_) \
+  { @key_, @value_ }                                   \
+  ,
+static const KnownMonochromeSetting kKnownMonochromeSettings[] = {
+    CUPS_EACH_MONOCHROME_PRINTER_SETTING(DECLARE_KNOWN_MONOCHROME_SETTING)};
+#undef DECLARE_KNOWN_MONOCHROME_SETTING
+
+NSPrintInfo* nsPrintSettingsX::CreateOrCopyPrintInfo(bool aWithScaling) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // If we have a printInfo that came from the system print UI, use it so that
+  // any printer-specific settings we don't know about will still be used.
+  if (mSystemPrintInfo) {
+    NSPrintInfo* sysPrintInfo = [mSystemPrintInfo copy];
+    // Any required scaling will be done by Gecko, so we don't want it here.
+    [sysPrintInfo setScalingFactor:1.0f];
+    return sysPrintInfo;
+  }
+
+  // Note that the app shared `sharedPrintInfo` object is special!  The system
+  // print dialog and print settings dialog update it with the values chosen
+  // by the user.  Using that object here to initialize new nsPrintSettingsX
+  // objects could mask bugs in our code where we fail to save and/or restore
+  // print settings ourselves (e.g., bug 1636725).  On other platforms we only
+  // initialize new nsPrintSettings objects from the settings that we save to
+  // prefs.  Perhaps we should stop using sharedPrintInfo here for consistency?
+  NSPrintInfo* printInfo = [[NSPrintInfo sharedPrintInfo] copy];
+
+  NSSize paperSize;
+  if (GetSheetOrientation() == kPortraitOrientation) {
+    paperSize.width = CocoaPointsFromPaperSize(mPaperWidth);
+    paperSize.height = CocoaPointsFromPaperSize(mPaperHeight);
+  } else {
+    paperSize.width = CocoaPointsFromPaperSize(mPaperHeight);
+    paperSize.height = CocoaPointsFromPaperSize(mPaperWidth);
+  }
+  [printInfo setPaperSize:paperSize];
+
+  if (paperSize.width > paperSize.height) {
+    [printInfo setOrientation:NSPaperOrientationLandscape];
+  } else {
+    [printInfo setOrientation:NSPaperOrientationPortrait];
+  }
+
+  [printInfo setTopMargin:mUnwriteableMargin.top];
+  [printInfo setRightMargin:mUnwriteableMargin.right];
+  [printInfo setBottomMargin:mUnwriteableMargin.bottom];
+  [printInfo setLeftMargin:mUnwriteableMargin.left];
+
+  // If the printer name is the name of our pseudo print-to-PDF printer, the
+  // following `setPrinter` call will fail silently, since macOS doesn't know
+  // anything about it. That's OK, because mPrinter is our canonical source of
+  // truth.
+  // Actually, it seems Mac OS X 10.12 (the oldest version of Mac that we
+  // support) hangs if the printer name is not recognized. For now we explicitly
+  // check for our print-to-PDF printer, but that is not ideal since we should
+  // really localize the name of this printer at some point. Once we drop
+  // support for 10.12 we should remove this check.
+  if (!mPrinter.EqualsLiteral("Mozilla Save to PDF")) {
+    [printInfo setPrinter:[NSPrinter printerWithName:nsCocoaUtils::ToNSString(
+                                                         mPrinter)]];
+  }
+
+  // Scaling is handled by gecko, we do NOT want the cocoa printing system to
+  // add a second scaling on top of that. So we only set the true scaling factor
+  // here if the caller explicitly asked for it.
+  [printInfo setScalingFactor:CGFloat(aWithScaling ? mScaling : 1.0f)];
+
+  const bool allPages = mPageRanges.IsEmpty();
+
+  NSMutableDictionary* dict = [printInfo dictionary];
+  [dict setObject:[NSNumber numberWithInt:mNumCopies] forKey:NSPrintCopies];
+  [dict setObject:[NSNumber numberWithBool:allPages] forKey:NSPrintAllPages];
+
+  int32_t start = 1;
+  int32_t end = 1;
+  for (size_t i = 0; i < mPageRanges.Length(); i += 2) {
+    start = std::min(start, mPageRanges[i]);
+    end = std::max(end, mPageRanges[i + 1]);
+  }
+
+  [dict setObject:[NSNumber numberWithInt:start] forKey:NSPrintFirstPage];
+  [dict setObject:[NSNumber numberWithInt:end] forKey:NSPrintLastPage];
+
+  NSURL* jobSavingURL = nullptr;
+  if (!mToFileName.IsEmpty()) {
+    jobSavingURL =
+        [NSURL fileURLWithPath:nsCocoaUtils::ToNSString(mToFileName)];
+    if (jobSavingURL) {
+      // Note: the PMPrintSettingsSetJobName call in nsPrintDialogServiceX::Show
+      // seems to mean that we get a sensible file name pre-populated in the
+      // dialog there, although our mToFileName is expected to be a full path,
+      // and it's less clear where the rest of the path (the directory to save
+      // to) in nsPrintDialogServiceX::Show comes from (perhaps from the use
+      // of `sharedPrintInfo` to initialize new nsPrintSettingsX objects).
+      [dict setObject:jobSavingURL forKey:NSPrintJobSavingURL];
+    }
+  }
+
+  if (mDisposition.IsEmpty()) {
+    // NOTE: It's unclear what to do for kOutputDestinationStream but this is
+    // only for the native print dialog where that can't happen.
+    if (mOutputDestination == kOutputDestinationFile) {
+      [printInfo setJobDisposition:NSPrintSaveJob];
+    } else {
+      [printInfo setJobDisposition:NSPrintSpoolJob];
+    }
+  } else {
+    [printInfo setJobDisposition:nsCocoaUtils::ToNSString(mDisposition)];
+  }
+
+  PMDuplexMode duplexSetting;
+  switch (mDuplex) {
+    default:
+      // This can't happen :) but if it does, we treat it as "none".
+      MOZ_FALLTHROUGH_ASSERT("Unknown duplex value");
+    case kDuplexNone:
+      duplexSetting = kPMDuplexNone;
+      break;
+    case kDuplexFlipOnLongEdge:
+      duplexSetting = kPMDuplexNoTumble;
+      break;
+    case kDuplexFlipOnShortEdge:
+      duplexSetting = kPMDuplexTumble;
+      break;
+  }
+
+  NSMutableDictionary* printSettings = [printInfo printSettings];
+  [printSettings setObject:[NSNumber numberWithUnsignedShort:duplexSetting]
+                    forKey:@"com_apple_print_PrintSettings_PMDuplexing"];
+
+  if (mDestination != kPMDestinationInvalid) {
+    // Required to support PDF-workflow destinations such as Save to Web
+    // Receipts.
+    [printSettings
+        setObject:[NSNumber numberWithUnsignedShort:mDestination]
+           forKey:@"com_apple_print_PrintSettings_PMDestinationType"];
+    if (jobSavingURL) {
+      [printSettings
+          setObject:[jobSavingURL absoluteString]
+             forKey:@"com_apple_print_PrintSettings_PMOutputFilename"];
+    }
+  }
+
+  if (StaticPrefs::print_cups_monochrome_enabled() && !GetPrintInColor()) {
+    for (const auto& setting : kKnownMonochromeSettings) {
+      [printSettings setObject:setting.mValue forKey:setting.mName];
+    }
+    auto applySetting = [&](const nsACString& aKey, const nsACString& aValue) {
+      [printSettings setObject:nsCocoaUtils::ToNSString(aValue)
+                        forKey:nsCocoaUtils::ToNSString(aKey)];
+    };
+    nsPrinterCUPS::ForEachExtraMonochromeSetting(applySetting);
+  }
+
+  return printInfo;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nullptr);
+}
+
+void nsPrintSettingsX::SetFromPrintInfo(NSPrintInfo* aPrintInfo,
+                                        bool aAdoptPrintInfo) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // Set page-size/margins.
+  NSSize paperSize = [aPrintInfo paperSize];
+  const bool areSheetsOfPaperPortraitMode =
+      ([aPrintInfo orientation] == NSPaperOrientationPortrait);
+
+  // If our MacOS print settings say that we're producing portrait-mode sheets
+  // of paper, then our page format must also be portrait-mode; unless we've
+  // got a pages-per-sheet value with orthogonal pages/sheets, in which case
+  // it's reversed.
+  const bool arePagesPortraitMode =
+      (areSheetsOfPaperPortraitMode != HasOrthogonalPagesPerSheet());
+
+  if (arePagesPortraitMode) {
+    mOrientation = nsIPrintSettings::kPortraitOrientation;
+    SetPaperWidth(PaperSizeFromCocoaPoints(paperSize.width));
+    SetPaperHeight(PaperSizeFromCocoaPoints(paperSize.height));
+  } else {
+    mOrientation = nsIPrintSettings::kLandscapeOrientation;
+    SetPaperWidth(PaperSizeFromCocoaPoints(paperSize.height));
+    SetPaperHeight(PaperSizeFromCocoaPoints(paperSize.width));
+  }
+
+  mUnwriteableMargin.top = static_cast<int32_t>([aPrintInfo topMargin]);
+  mUnwriteableMargin.right = static_cast<int32_t>([aPrintInfo rightMargin]);
+  mUnwriteableMargin.bottom = static_cast<int32_t>([aPrintInfo bottomMargin]);
+  mUnwriteableMargin.left = static_cast<int32_t>([aPrintInfo leftMargin]);
+
+  if (aAdoptPrintInfo) {
+    // Keep a reference to the printInfo; it may have settings that we don't
+    // know how to handle otherwise.
+    if (mSystemPrintInfo != aPrintInfo) {
+      if (mSystemPrintInfo) {
+        [mSystemPrintInfo release];
+      }
+      mSystemPrintInfo = aPrintInfo;
+      [mSystemPrintInfo retain];
+    }
+  } else {
+    // Clear any stored printInfo.
+    if (mSystemPrintInfo) {
+      [mSystemPrintInfo release];
+      mSystemPrintInfo = nullptr;
+    }
+  }
+
+  nsCocoaUtils::GetStringForNSString([[aPrintInfo printer] name], mPrinter);
+
+  // Only get the scaling value if shrink-to-fit is not selected:
+  bool isShrinkToFitChecked;
+  GetShrinkToFit(&isShrinkToFitChecked);
+  if (!isShrinkToFitChecked) {
+    // Limit scaling precision to whole percentage values.
+    mScaling = round(double([aPrintInfo scalingFactor]) * 100.0) / 100.0;
+  }
+
+  mOutputDestination = [&] {
+    if ([aPrintInfo jobDisposition] == NSPrintSaveJob) {
+      return kOutputDestinationFile;
+    }
+    return kOutputDestinationPrinter;
+  }();
+
+  NSDictionary* dict = [aPrintInfo dictionary];
+  const char* filePath =
+      [[dict objectForKey:NSPrintJobSavingURL] fileSystemRepresentation];
+  if (filePath && *filePath) {
+    CopyUTF8toUTF16(Span(filePath, strlen(filePath)), mToFileName);
+  }
+
+  nsCocoaUtils::GetStringForNSString([aPrintInfo jobDisposition], mDisposition);
+
+  mNumCopies = [[dict objectForKey:NSPrintCopies] intValue];
+  mPageRanges.Clear();
+  if (![[dict objectForKey:NSPrintAllPages] boolValue]) {
+    mPageRanges.AppendElement([[dict objectForKey:NSPrintFirstPage] intValue]);
+    mPageRanges.AppendElement([[dict objectForKey:NSPrintLastPage] intValue]);
+  }
+
+  NSDictionary* printSettings = [aPrintInfo printSettings];
+  NSNumber* value =
+      [printSettings objectForKey:@"com_apple_print_PrintSettings_PMDuplexing"];
+  if (value) {
+    PMDuplexMode duplexSetting = [value unsignedShortValue];
+    switch (duplexSetting) {
+      default:
+        // An unknown value is treated as None.
+        MOZ_FALLTHROUGH_ASSERT("Unknown duplex value");
+      case kPMDuplexNone:
+        mDuplex = kDuplexNone;
+        break;
+      case kPMDuplexNoTumble:
+        mDuplex = kDuplexFlipOnLongEdge;
+        break;
+      case kPMDuplexTumble:
+        mDuplex = kDuplexFlipOnShortEdge;
+        break;
+    }
+  } else {
+    // By default a printSettings dictionary doesn't initially contain the
+    // duplex key at all, so this is not an error; its absence just means no
+    // duplexing has been requested, so we return kDuplexNone.
+    mDuplex = kDuplexNone;
+  }
+
+  value = [printSettings
+      objectForKey:@"com_apple_print_PrintSettings_PMDestinationType"];
+  if (value) {
+    mDestination = [value unsignedShortValue];
+  }
+
+  const bool color = [&] {
+    if (StaticPrefs::print_cups_monochrome_enabled()) {
+      for (const auto& setting : kKnownMonochromeSettings) {
+        NSString* value = [printSettings objectForKey:setting.mName];
+        if (!value) {
+          continue;
+        }
+        if ([setting.mValue isEqualToString:value]) {
+          return false;
+        }
+      }
+    }
+    return true;
+  }();
+
+  SetPrintInColor(color);
+
+  SetIsInitializedFromPrinter(true);
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
diff --git a/widget/cocoa/nsSandboxViolationSink.h b/widget/cocoa/nsSandboxViolationSink.h
new file mode 100644
index 0000000000..d4b6e7ce07
--- /dev/null
+++ b/widget/cocoa/nsSandboxViolationSink.h
@@ -0,0 +1,36 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsSandboxViolationSink_h_
+#define nsSandboxViolationSink_h_
+
+#include <stdint.h>
+
+// Class for tracking sandbox violations.  Currently it just logs them to
+// stdout and the system console.  In the future it may do more.
+
+// What makes this possible is the fact that Apple' sandboxd calls
+// notify_post("com.apple.sandbox.violation.*") whenever it's notified by the
+// Sandbox kernel extension of a sandbox violation.  We register to receive
+// these notifications.  But the notifications are empty, and are sent for
+// every violation in every process.  So we need to do more to get only "our"
+// violations, and to find out what kind of violation they were.  See the
+// implementation of nsSandboxViolationSink::ViolationHandler().
+
+#define SANDBOX_VIOLATION_QUEUE_NAME "org.mozilla.sandbox.violation.queue"
+#define SANDBOX_VIOLATION_NOTIFICATION_NAME "com.apple.sandbox.violation.*"
+
+class nsSandboxViolationSink {
+ public:
+  static void Start();
+  static void Stop();
+
+ private:
+  static void ViolationHandler();
+  static int mNotifyToken;
+  static uint64_t mLastMsgReceived;
+};
+
+#endif  // nsSandboxViolationSink_h_
diff --git a/widget/cocoa/nsSandboxViolationSink.mm b/widget/cocoa/nsSandboxViolationSink.mm
new file mode 100644
index 0000000000..611e0387b1
--- /dev/null
+++ b/widget/cocoa/nsSandboxViolationSink.mm
@@ -0,0 +1,112 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsSandboxViolationSink.h"
+
+#import <Foundation/NSObjCRuntime.h>
+
+#include <unistd.h>
+#include <time.h>
+#include <asl.h>
+#include <dispatch/dispatch.h>
+#include <notify.h>
+#include "mozilla/Preferences.h"
+#include "mozilla/Sprintf.h"
+
+int nsSandboxViolationSink::mNotifyToken = 0;
+uint64_t nsSandboxViolationSink::mLastMsgReceived = 0;
+
+void nsSandboxViolationSink::Start() {
+  if (mNotifyToken) {
+    return;
+  }
+  notify_register_dispatch(SANDBOX_VIOLATION_NOTIFICATION_NAME, &mNotifyToken,
+                           dispatch_queue_create(SANDBOX_VIOLATION_QUEUE_NAME,
+                                                 DISPATCH_QUEUE_SERIAL),
+                           ^(int token) {
+                             ViolationHandler();
+                           });
+}
+
+void nsSandboxViolationSink::Stop() {
+  if (!mNotifyToken) {
+    return;
+  }
+  notify_cancel(mNotifyToken);
+  mNotifyToken = 0;
+}
+
+// We need to query syslogd to find out what violations occurred, and whether
+// they were "ours".  We can use the Apple System Log facility to do this.
+// Besides calling notify_post("com.apple.sandbox.violation.*"), Apple's
+// sandboxd also reports all sandbox violations (sent to it by the Sandbox
+// kernel extension) to syslogd, which stores them and makes them viewable
+// in the system console.  This is the database we query.
+
+// ViolationHandler() is always called on its own secondary thread.  This
+// makes it unlikely it will interfere with other browser activity.
+
+void nsSandboxViolationSink::ViolationHandler() {
+  aslmsg query = asl_new(ASL_TYPE_QUERY);
+
+  asl_set_query(query, ASL_KEY_FACILITY, "com.apple.sandbox",
+                ASL_QUERY_OP_EQUAL);
+
+  // Only get reports that were generated very recently.
+  char query_time[30] = {0};
+  SprintfLiteral(query_time, "%li", time(NULL) - 2);
+  asl_set_query(query, ASL_KEY_TIME, query_time,
+                ASL_QUERY_OP_NUMERIC | ASL_QUERY_OP_GREATER_EQUAL);
+
+  // This code is easier to test if we don't just track "our" violations,
+  // which are (normally) few and far between.  For example (for the time
+  // being at least) four appleeventsd sandbox violations happen every time
+  // we start the browser in e10s mode.  But it makes sense to default to
+  // only tracking "our" violations.
+  if (mozilla::Preferences::GetBool(
+          "security.sandbox.mac.track.violations.oursonly", true)) {
+    // This makes each of our processes log its own violations.  It might
+    // be better to make the chrome process log all the other processes'
+    // violations.
+    char query_pid[20] = {0};
+    SprintfLiteral(query_pid, "%u", getpid());
+    asl_set_query(query, ASL_KEY_REF_PID, query_pid, ASL_QUERY_OP_EQUAL);
+  }
+
+  aslresponse response = asl_search(nullptr, query);
+
+  // Each time ViolationHandler() is called we grab as many messages as are
+  // available.  Otherwise we might not get them all.
+  if (response) {
+    while (true) {
+      aslmsg hit = nullptr;
+      aslmsg found = nullptr;
+      const char* id_str;
+
+      while ((hit = aslresponse_next(response))) {
+        // Record the message id to avoid logging the same violation more
+        // than once.
+        id_str = asl_get(hit, ASL_KEY_MSG_ID);
+        uint64_t id_val = atoll(id_str);
+        if (id_val <= mLastMsgReceived) {
+          continue;
+        }
+        mLastMsgReceived = id_val;
+        found = hit;
+        break;
+      }
+      if (!found) {
+        break;
+      }
+
+      const char* pid_str = asl_get(found, ASL_KEY_REF_PID);
+      const char* message_str = asl_get(found, ASL_KEY_MSG);
+      NSLog(@"nsSandboxViolationSink::ViolationHandler(): id %s, pid %s, "
+            @"message %s",
+            id_str, pid_str, message_str);
+    }
+    aslresponse_free(response);
+  }
+}
diff --git a/widget/cocoa/nsSound.h b/widget/cocoa/nsSound.h
new file mode 100644
index 0000000000..cf3b02bd77
--- /dev/null
+++ b/widget/cocoa/nsSound.h
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsSound_h_
+#define nsSound_h_
+
+#include "nsISound.h"
+#include "nsIStreamLoader.h"
+
+class nsSound : public nsISound, public nsIStreamLoaderObserver {
+ public:
+  nsSound();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISOUND
+  NS_DECL_NSISTREAMLOADEROBSERVER
+
+ protected:
+  virtual ~nsSound();
+};
+
+#endif  // nsSound_h_
diff --git a/widget/cocoa/nsSound.mm b/widget/cocoa/nsSound.mm
new file mode 100644
index 0000000000..cbaad44be7
--- /dev/null
+++ b/widget/cocoa/nsSound.mm
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsSound.h"
+#include "nsContentUtils.h"
+#include "nsObjCExceptions.h"
+#include "nsNetUtil.h"
+#include "nsCOMPtr.h"
+#include "nsIURL.h"
+#include "nsString.h"
+
+#import <Cocoa/Cocoa.h>
+
+NS_IMPL_ISUPPORTS(nsSound, nsISound, nsIStreamLoaderObserver)
+
+nsSound::nsSound() {}
+
+nsSound::~nsSound() {}
+
+NS_IMETHODIMP
+nsSound::Beep() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSBeep();
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsSound::OnStreamComplete(nsIStreamLoader* aLoader, nsISupports* context,
+                          nsresult aStatus, uint32_t dataLen,
+                          const uint8_t* data) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  NSData* value = [NSData dataWithBytes:data length:dataLen];
+
+  NSSound* sound = [[NSSound alloc] initWithData:value];
+
+  [sound play];
+
+  [sound autorelease];
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+NS_IMETHODIMP
+nsSound::Play(nsIURL* aURL) {
+  nsCOMPtr<nsIURI> uri(aURL);
+  nsCOMPtr<nsIStreamLoader> loader;
+  return NS_NewStreamLoader(
+      getter_AddRefs(loader), uri,
+      this,  // aObserver
+      nsContentUtils::GetSystemPrincipal(),
+      nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
+      nsIContentPolicy::TYPE_OTHER);
+}
+
+NS_IMETHODIMP
+nsSound::Init() { return NS_OK; }
+
+NS_IMETHODIMP
+nsSound::PlayEventSound(uint32_t aEventId) {
+  // Mac doesn't have system sound settings for each user actions.
+  return NS_OK;
+}
diff --git a/widget/cocoa/nsStandaloneNativeMenu.h b/widget/cocoa/nsStandaloneNativeMenu.h
new file mode 100644
index 0000000000..9d43e5e64d
--- /dev/null
+++ b/widget/cocoa/nsStandaloneNativeMenu.h
@@ -0,0 +1,27 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsStandaloneNativeMenu_h_
+#define nsStandaloneNativeMenu_h_
+
+#include "nsIStandaloneNativeMenu.h"
+#include "NativeMenuMac.h"
+
+class nsStandaloneNativeMenu : public nsIStandaloneNativeMenu {
+ public:
+  nsStandaloneNativeMenu();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISTANDALONENATIVEMENU
+
+  RefPtr<mozilla::widget::NativeMenuMac> GetNativeMenu() { return mMenu; }
+
+ protected:
+  virtual ~nsStandaloneNativeMenu();
+
+  RefPtr<mozilla::widget::NativeMenuMac> mMenu;
+};
+
+#endif
diff --git a/widget/cocoa/nsStandaloneNativeMenu.mm b/widget/cocoa/nsStandaloneNativeMenu.mm
new file mode 100644
index 0000000000..d5a70f817e
--- /dev/null
+++ b/widget/cocoa/nsStandaloneNativeMenu.mm
@@ -0,0 +1,81 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsStandaloneNativeMenu.h"
+
+#include "mozilla/dom/Element.h"
+#include "NativeMenuMac.h"
+#include "nsISupports.h"
+#include "nsGkAtoms.h"
+
+using namespace mozilla;
+
+using mozilla::dom::Element;
+
+NS_IMPL_ISUPPORTS(nsStandaloneNativeMenu, nsIStandaloneNativeMenu)
+
+nsStandaloneNativeMenu::nsStandaloneNativeMenu() = default;
+
+nsStandaloneNativeMenu::~nsStandaloneNativeMenu() = default;
+
+NS_IMETHODIMP
+nsStandaloneNativeMenu::Init(Element* aElement) {
+  NS_ASSERTION(mMenu == nullptr, "nsNativeMenu::Init - mMenu not null!");
+
+  NS_ENSURE_ARG(aElement);
+
+  if (!aElement->IsAnyOfXULElements(nsGkAtoms::menu, nsGkAtoms::menupopup)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mMenu = new mozilla::widget::NativeMenuMac(aElement);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsStandaloneNativeMenu::MenuWillOpen(bool* aResult) {
+  NS_ASSERTION(mMenu != nullptr,
+               "nsStandaloneNativeMenu::OnOpen - mMenu is null!");
+
+  mMenu->MenuWillOpen();
+
+  *aResult = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsStandaloneNativeMenu::ActivateNativeMenuItemAt(
+    const nsAString& aIndexString) {
+  if (!mMenu) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  if (mMenu->ActivateNativeMenuItemAt(aIndexString)) {
+    return NS_OK;
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsStandaloneNativeMenu::ForceUpdateNativeMenuAt(const nsAString& aIndexString) {
+  if (!mMenu) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  mMenu->ForceUpdateNativeMenuAt(aIndexString);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsStandaloneNativeMenu::Dump() {
+  mMenu->Dump();
+
+  return NS_OK;
+}
diff --git a/widget/cocoa/nsSystemStatusBarCocoa.h b/widget/cocoa/nsSystemStatusBarCocoa.h
new file mode 100644
index 0000000000..2af13e2805
--- /dev/null
+++ b/widget/cocoa/nsSystemStatusBarCocoa.h
@@ -0,0 +1,40 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsSystemStatusBarCocoa_h_
+#define nsSystemStatusBarCocoa_h_
+
+#include "mozilla/RefPtr.h"
+#include "nsISystemStatusBar.h"
+#include "nsClassHashtable.h"
+
+namespace mozilla::widget {
+class NativeMenuMac;
+}
+@class NSStatusItem;
+
+class nsSystemStatusBarCocoa : public nsISystemStatusBar {
+ public:
+  nsSystemStatusBarCocoa() {}
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISYSTEMSTATUSBAR
+
+ protected:
+  virtual ~nsSystemStatusBarCocoa() {}
+
+  struct StatusItem {
+    explicit StatusItem(mozilla::widget::NativeMenuMac* aMenu);
+    ~StatusItem();
+
+   private:
+    RefPtr<mozilla::widget::NativeMenuMac> mMenu;
+    NSStatusItem* mStatusItem;
+  };
+
+  nsClassHashtable<nsISupportsHashKey, StatusItem> mItems;
+};
+
+#endif  // nsSystemStatusBarCocoa_h_
diff --git a/widget/cocoa/nsSystemStatusBarCocoa.mm b/widget/cocoa/nsSystemStatusBarCocoa.mm
new file mode 100644
index 0000000000..f46ee0ce3e
--- /dev/null
+++ b/widget/cocoa/nsSystemStatusBarCocoa.mm
@@ -0,0 +1,70 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsComponentManagerUtils.h"
+#include "nsSystemStatusBarCocoa.h"
+#include "NativeMenuMac.h"
+#include "nsObjCExceptions.h"
+#include "mozilla/dom/Element.h"
+
+using mozilla::dom::Element;
+using mozilla::widget::NativeMenuMac;
+
+NS_IMPL_ISUPPORTS(nsSystemStatusBarCocoa, nsISystemStatusBar)
+
+NS_IMETHODIMP
+nsSystemStatusBarCocoa::AddItem(Element* aElement) {
+  if (!aElement->IsAnyOfXULElements(nsGkAtoms::menu, nsGkAtoms::menupopup)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<NativeMenuMac> menu = new NativeMenuMac(aElement);
+
+  nsCOMPtr<nsISupports> keyPtr = aElement;
+  mItems.InsertOrUpdate(keyPtr, mozilla::MakeUnique<StatusItem>(menu));
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSystemStatusBarCocoa::RemoveItem(Element* aElement) {
+  mItems.Remove(aElement);
+  return NS_OK;
+}
+
+nsSystemStatusBarCocoa::StatusItem::StatusItem(NativeMenuMac* aMenu)
+    : mMenu(aMenu) {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  MOZ_COUNT_CTOR(nsSystemStatusBarCocoa::StatusItem);
+
+  mStatusItem = [[NSStatusBar.systemStatusBar
+      statusItemWithLength:NSSquareStatusItemLength] retain];
+  mStatusItem.menu = mMenu->NativeNSMenu();
+  mStatusItem.highlightMode = YES;
+
+  // We want the status item to get its image from menu item that mMenu was
+  // initialized with. Icon loads are asynchronous, so we need to let the menu
+  // know about the item so that it can update its icon as soon as it has
+  // loaded.
+  mMenu->SetContainerStatusBarItem(mStatusItem);
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
+
+nsSystemStatusBarCocoa::StatusItem::~StatusItem() {
+  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
+
+  mMenu->SetContainerStatusBarItem(nil);
+  [NSStatusBar.systemStatusBar removeStatusItem:mStatusItem];
+  [mStatusItem release];
+  mStatusItem = nil;
+
+  MOZ_COUNT_DTOR(nsSystemStatusBarCocoa::StatusItem);
+
+  NS_OBJC_END_TRY_ABORT_BLOCK;
+}
diff --git a/widget/cocoa/nsToolkit.h b/widget/cocoa/nsToolkit.h
new file mode 100644
index 0000000000..46b08d0ebe
--- /dev/null
+++ b/widget/cocoa/nsToolkit.h
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsToolkit_h_
+#define nsToolkit_h_
+
+#include "nscore.h"
+
+#import <Carbon/Carbon.h>
+#import <Cocoa/Cocoa.h>
+#import <objc/Object.h>
+#import <IOKit/IOKitLib.h>
+
+class nsToolkit {
+ public:
+  nsToolkit();
+  virtual ~nsToolkit();
+
+  static nsToolkit* GetToolkit();
+
+  static void Shutdown() {
+    delete gToolkit;
+    gToolkit = nullptr;
+  }
+
+  static void PostSleepWakeNotification(const char* aNotification);
+
+  static nsresult SwizzleMethods(Class aClass, SEL orgMethod, SEL posedMethod,
+                                 bool classMethods = false);
+
+  void MonitorAllProcessMouseEvents();
+  void StopMonitoringAllProcessMouseEvents();
+
+ protected:
+  nsresult RegisterForSleepWakeNotifications();
+  void RemoveSleepWakeNotifications();
+
+ protected:
+  static nsToolkit* gToolkit;
+
+  CFRunLoopSourceRef mSleepWakeNotificationRLS;
+  io_object_t mPowerNotifier;
+
+  id mAllProcessMouseMonitor;
+};
+
+#endif  // nsToolkit_h_
diff --git a/widget/cocoa/nsToolkit.mm b/widget/cocoa/nsToolkit.mm
new file mode 100644
index 0000000000..065100a107
--- /dev/null
+++ b/widget/cocoa/nsToolkit.mm
@@ -0,0 +1,265 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsToolkit.h"
+
+#include <ctype.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <mach/mach_port.h>
+#include <mach/mach_interface.h>
+#include <mach/mach_init.h>
+
+extern "C" {
+#include <mach-o/getsect.h>
+}
+#include <unistd.h>
+#include <dlfcn.h>
+
+#import <Cocoa/Cocoa.h>
+#import <IOKit/pwr_mgt/IOPMLib.h>
+#import <IOKit/IOMessage.h>
+
+#include "nsCocoaUtils.h"
+#include "nsObjCExceptions.h"
+
+#include "nsGkAtoms.h"
+#include "nsIRollupListener.h"
+#include "nsIWidget.h"
+#include "nsBaseWidget.h"
+
+#include "nsIObserverService.h"
+
+#include "mozilla/Preferences.h"
+#include "mozilla/Services.h"
+
+#include "NativeMenuSupport.h"
+
+using namespace mozilla;
+
+static io_connect_t gRootPort = MACH_PORT_NULL;
+
+nsToolkit* nsToolkit::gToolkit = nullptr;
+
+nsToolkit::nsToolkit()
+    : mSleepWakeNotificationRLS(nullptr),
+      mPowerNotifier{0},
+      mAllProcessMouseMonitor(nil) {
+  MOZ_COUNT_CTOR(nsToolkit);
+  RegisterForSleepWakeNotifications();
+}
+
+nsToolkit::~nsToolkit() {
+  MOZ_COUNT_DTOR(nsToolkit);
+  RemoveSleepWakeNotifications();
+  StopMonitoringAllProcessMouseEvents();
+}
+
+void nsToolkit::PostSleepWakeNotification(const char* aNotification) {
+  nsCOMPtr<nsIObserverService> observerService = services::GetObserverService();
+  if (observerService)
+    observerService->NotifyObservers(nullptr, aNotification, nullptr);
+}
+
+// http://developer.apple.com/documentation/DeviceDrivers/Conceptual/IOKitFundamentals/PowerMgmt/chapter_10_section_3.html
+static void ToolkitSleepWakeCallback(void* refCon, io_service_t service,
+                                     natural_t messageType,
+                                     void* messageArgument) {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  switch (messageType) {
+    case kIOMessageSystemWillSleep:
+      // System is going to sleep now.
+      nsToolkit::PostSleepWakeNotification(NS_WIDGET_SLEEP_OBSERVER_TOPIC);
+      ::IOAllowPowerChange(gRootPort, (long)messageArgument);
+      break;
+
+    case kIOMessageCanSystemSleep:
+      // In this case, the computer has been idle for several minutes
+      // and will sleep soon so you must either allow or cancel
+      // this notification. Important: if you don’t respond, there will
+      // be a 30-second timeout before the computer sleeps.
+      // In Mozilla's case, we always allow sleep.
+      ::IOAllowPowerChange(gRootPort, (long)messageArgument);
+      break;
+
+    case kIOMessageSystemHasPoweredOn:
+      // Handle wakeup.
+      nsToolkit::PostSleepWakeNotification(NS_WIDGET_WAKE_OBSERVER_TOPIC);
+      break;
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+nsresult nsToolkit::RegisterForSleepWakeNotifications() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  IONotificationPortRef notifyPortRef;
+
+  NS_ASSERTION(!mSleepWakeNotificationRLS, "Already registered for sleep/wake");
+
+  gRootPort = ::IORegisterForSystemPower(
+      0, &notifyPortRef, ToolkitSleepWakeCallback, &mPowerNotifier);
+  if (gRootPort == MACH_PORT_NULL) {
+    NS_ERROR("IORegisterForSystemPower failed");
+    return NS_ERROR_FAILURE;
+  }
+
+  mSleepWakeNotificationRLS =
+      ::IONotificationPortGetRunLoopSource(notifyPortRef);
+  ::CFRunLoopAddSource(::CFRunLoopGetCurrent(), mSleepWakeNotificationRLS,
+                       kCFRunLoopDefaultMode);
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void nsToolkit::RemoveSleepWakeNotifications() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mSleepWakeNotificationRLS) {
+    ::IODeregisterForSystemPower(&mPowerNotifier);
+    ::CFRunLoopRemoveSource(::CFRunLoopGetCurrent(), mSleepWakeNotificationRLS,
+                            kCFRunLoopDefaultMode);
+
+    mSleepWakeNotificationRLS = nullptr;
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Cocoa Firefox's use of custom context menus requires that we explicitly
+// handle mouse events from other processes that the OS handles
+// "automatically" for native context menus -- mouseMoved events so that
+// right-click context menus work properly when our browser doesn't have the
+// focus (bmo bug 368077), and mouseDown events so that our browser can
+// dismiss a context menu when a mouseDown happens in another process (bmo
+// bug 339945).
+void nsToolkit::MonitorAllProcessMouseEvents() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mozilla::widget::NativeMenuSupport::ShouldUseNativeContextMenus()) {
+    // Don't do this if we are using native context menus.
+    return;
+  }
+
+  if (getenv("MOZ_NO_GLOBAL_MOUSE_MONITOR")) return;
+
+  if (mAllProcessMouseMonitor == nil) {
+    mAllProcessMouseMonitor = [NSEvent
+        addGlobalMonitorForEventsMatchingMask:NSEventMaskLeftMouseDown |
+                                              NSEventMaskLeftMouseDown
+                                      handler:^(NSEvent* evt) {
+                                        if ([NSApp isActive]) {
+                                          return;
+                                        }
+
+                                        nsIRollupListener* rollupListener =
+                                            nsBaseWidget::
+                                                GetActiveRollupListener();
+                                        if (!rollupListener) {
+                                          return;
+                                        }
+
+                                        nsCOMPtr<nsIWidget> rollupWidget =
+                                            rollupListener->GetRollupWidget();
+                                        if (!rollupWidget) {
+                                          return;
+                                        }
+
+                                        NSWindow* ctxMenuWindow =
+                                            (NSWindow*)
+                                                rollupWidget->GetNativeData(
+                                                    NS_NATIVE_WINDOW);
+                                        if (!ctxMenuWindow) {
+                                          return;
+                                        }
+
+                                        // Don't roll up the rollup widget if
+                                        // our mouseDown happens over it (doing
+                                        // so would break the corresponding
+                                        // context menu).
+                                        NSPoint screenLocation =
+                                            [NSEvent mouseLocation];
+                                        if (NSPointInRect(
+                                                screenLocation,
+                                                [ctxMenuWindow frame])) {
+                                          return;
+                                        }
+
+                                        rollupListener->Rollup({});
+                                      }];
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+void nsToolkit::StopMonitoringAllProcessMouseEvents() {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (mAllProcessMouseMonitor != nil) {
+    [NSEvent removeMonitor:mAllProcessMouseMonitor];
+    mAllProcessMouseMonitor = nil;
+  }
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// Return the nsToolkit instance.  If a toolkit does not yet exist, then one
+// will be created.
+// static
+nsToolkit* nsToolkit::GetToolkit() {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if (!gToolkit) {
+    gToolkit = new nsToolkit();
+  }
+
+  return gToolkit;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nullptr);
+}
+
+// An alternative to [NSObject poseAsClass:] that isn't deprecated on OS X
+// Leopard and is available to 64-bit binaries on Leopard and above.  Based on
+// ideas and code from http://www.cocoadev.com/index.pl?MethodSwizzling.
+// Since the Method type becomes an opaque type as of Objective-C 2.0, we'll
+// have to switch to using accessor methods like
+// method_exchangeImplementations() when we build 64-bit binaries that use
+// Objective-C 2.0 (on and for Leopard and above).
+//
+// Be aware that, if aClass doesn't have an orgMethod selector but one of its
+// superclasses does, the method substitution will (in effect) take place in
+// that superclass (rather than in aClass itself).  The substitution has
+// effect on the class where it takes place and all of that class's
+// subclasses.  In order for method swizzling to work properly, posedMethod
+// needs to be unique in the class where the substitution takes place and all
+// of its subclasses.
+nsresult nsToolkit::SwizzleMethods(Class aClass, SEL orgMethod, SEL posedMethod,
+                                   bool classMethods) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  Method original = nil;
+  Method posed = nil;
+
+  if (classMethods) {
+    original = class_getClassMethod(aClass, orgMethod);
+    posed = class_getClassMethod(aClass, posedMethod);
+  } else {
+    original = class_getInstanceMethod(aClass, orgMethod);
+    posed = class_getInstanceMethod(aClass, posedMethod);
+  }
+
+  if (!original || !posed) return NS_ERROR_FAILURE;
+
+  method_exchangeImplementations(original, posed);
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
diff --git a/widget/cocoa/nsTouchBar.h b/widget/cocoa/nsTouchBar.h
new file mode 100644
index 0000000000..4d0aa28d63
--- /dev/null
+++ b/widget/cocoa/nsTouchBar.h
@@ -0,0 +1,141 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsTouchBar_h_
+#define nsTouchBar_h_
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsITouchBarHelper.h"
+#include "nsTouchBarInput.h"
+
+const NSTouchBarItemIdentifier kTouchBarBaseIdentifier =
+    @"com.mozilla.firefox.touchbar";
+
+/**
+ * Our TouchBar is its own delegate. This is adequate for our purposes,
+ * since the current implementation only defines Touch Bar buttons for the
+ * main Firefox window. If modals and other windows were to have custom
+ * Touch Bar views, each window would have to be a NSTouchBarDelegate so
+ * they could define their own custom sets of buttons.
+ */
+@interface nsTouchBar : NSTouchBar <NSTouchBarDelegate,
+                                    NSSharingServicePickerTouchBarItemDelegate,
+                                    NSSharingServiceDelegate> {
+  /**
+   * Link to the frontend API that determines which buttons appear
+   * in the Touch Bar
+   */
+  nsCOMPtr<nsITouchBarHelper> mTouchBarHelper;
+}
+
+/**
+ * Contains TouchBarInput representations of the inputs currently in
+ * the Touch Bar. Populated in `init` and updated by nsITouchBarUpdater.
+ */
+@property(strong) NSMutableDictionary<NSTouchBarItemIdentifier, TouchBarInput*>*
+    mappedLayoutItems;
+
+/**
+ * Stores buttons displayed in a NSScrollView. They must be stored separately
+ * because they are untethered from the nsTouchBar. As such, they
+ * cannot be retrieved with [NSTouchBar itemForIdentifier].
+ */
+@property(strong)
+    NSMutableDictionary<NSTouchBarItemIdentifier, NSCustomTouchBarItem*>*
+        scrollViewButtons;
+
+/**
+ * Returns an instance of nsTouchBar based on implementation details
+ * fetched from the frontend through nsTouchBarHelper.
+ */
+- (instancetype)init;
+
+/**
+ * If aInputs is not nil, a nsTouchBar containing the inputs specified is
+ * initialized. Otherwise, a nsTouchBar is initialized containing a default set
+ * of inputs.
+ */
+- (instancetype)initWithInputs:(NSMutableArray<TouchBarInput*>*)aInputs;
+
+- (void)dealloc;
+
+/**
+ * Creates a new NSTouchBarItem and adds it to the Touch Bar.
+ * Reads the passed identifier and creates the
+ * appropriate item type (eg. NSCustomTouchBarItem).
+ * Required as a member of NSTouchBarDelegate.
+ */
+- (NSTouchBarItem*)touchBar:(NSTouchBar*)aTouchBar
+      makeItemForIdentifier:(NSTouchBarItemIdentifier)aIdentifier;
+
+/**
+ * Updates an input on the Touch Bar by redirecting to one of the specific
+ * TouchBarItem types updaters.
+ * Returns true if the input was successfully updated.
+ */
+- (bool)updateItem:(TouchBarInput*)aInput;
+
+/**
+ * Helper function for updateItem. Checks to see if a given input exists within
+ * any of this Touch Bar's popovers and updates it if it exists.
+ */
+- (bool)maybeUpdatePopoverChild:(TouchBarInput*)aInput;
+
+/**
+ * Helper function for updateItem. Checks to see if a given input exists within
+ * any of this Touch Bar's scroll views and updates it if it exists.
+ */
+- (bool)maybeUpdateScrollViewChild:(TouchBarInput*)aInput;
+
+/**
+ * Helper function for updateItem. Replaces an item in the
+ * self.mappedLayoutItems dictionary.
+ */
+- (void)replaceMappedLayoutItem:(TouchBarInput*)aItem;
+
+/**
+ * Update or create various subclasses of TouchBarItem.
+ */
+- (void)updateButton:(NSCustomTouchBarItem*)aButton
+      withIdentifier:(NSTouchBarItemIdentifier)aIdentifier;
+- (void)updateMainButton:(NSCustomTouchBarItem*)aMainButton
+          withIdentifier:(NSTouchBarItemIdentifier)aIdentifier;
+- (void)updatePopover:(NSPopoverTouchBarItem*)aPopoverItem
+       withIdentifier:(NSTouchBarItemIdentifier)aIdentifier;
+- (void)updateScrollView:(NSCustomTouchBarItem*)aScrollViewItem
+          withIdentifier:(NSTouchBarItemIdentifier)aIdentifier;
+- (void)updateLabel:(NSTextField*)aLabel
+     withIdentifier:(NSTouchBarItemIdentifier)aIdentifier;
+- (NSTouchBarItem*)makeShareScrubberForIdentifier:
+    (NSTouchBarItemIdentifier)aIdentifier;
+
+/**
+ * If aShowing is true, aPopover is shown. Otherwise, it is hidden.
+ */
+- (void)showPopover:(TouchBarInput*)aPopover showing:(bool)aShowing;
+
+/**
+ *  Redirects button actions to the appropriate handler.
+ */
+- (void)touchBarAction:(id)aSender;
+
+/**
+ * Helper function to initialize a new nsTouchBarInputIcon and load an icon.
+ */
+- (void)loadIconForInput:(TouchBarInput*)aInput forItem:(NSTouchBarItem*)aItem;
+
+- (NSArray*)itemsForSharingServicePickerTouchBarItem:
+    (NSSharingServicePickerTouchBarItem*)aPickerTouchBarItem;
+
+- (NSArray<NSSharingService*>*)
+       sharingServicePicker:(NSSharingServicePicker*)aSharingServicePicker
+    sharingServicesForItems:(NSArray*)aItems
+    proposedSharingServices:(NSArray<NSSharingService*>*)aProposedServices;
+
+- (void)releaseJSObjects;
+
+@end  // nsTouchBar
+
+#endif  // nsTouchBar_h_
diff --git a/widget/cocoa/nsTouchBar.mm b/widget/cocoa/nsTouchBar.mm
new file mode 100644
index 0000000000..067ce03129
--- /dev/null
+++ b/widget/cocoa/nsTouchBar.mm
@@ -0,0 +1,650 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsTouchBar.h"
+
+#include <objc/runtime.h>
+
+#include "mozilla/MacStringHelpers.h"
+#include "mozilla/dom/Document.h"
+#include "nsArrayUtils.h"
+#include "nsCocoaUtils.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsIArray.h"
+#include "nsTouchBarInputIcon.h"
+#include "nsWidgetsCID.h"
+
+@implementation nsTouchBar
+
+// Used to tie action strings to buttons.
+static char sIdentifierAssociationKey;
+
+// The default space between inputs, used where layout is not automatic.
+static const uint32_t kInputSpacing = 8;
+// The width of buttons in Apple's Share ScrollView. We use this in our
+// ScrollViews to give them a native appearance.
+static const uint32_t kScrollViewButtonWidth = 144;
+static const uint32_t kInputIconSize = 16;
+
+// The system default width for Touch Bar inputs is 128px. This is double.
+#define MAIN_BUTTON_WIDTH 256
+
+#pragma mark - NSTouchBarDelegate
+
+- (instancetype)init {
+  return [self initWithInputs:nil];
+}
+
+- (instancetype)initWithInputs:(NSMutableArray<TouchBarInput*>*)aInputs {
+  if ((self = [super init])) {
+    mTouchBarHelper = do_GetService(NS_TOUCHBARHELPER_CID);
+    if (!mTouchBarHelper) {
+      NS_ERROR("Unable to create Touch Bar Helper.");
+      return nil;
+    }
+
+    self.delegate = self;
+    self.mappedLayoutItems = [NSMutableDictionary dictionary];
+    self.customizationAllowedItemIdentifiers = @[];
+
+    if (!aInputs) {
+      // This customization identifier is how users' custom layouts are saved by
+      // macOS. If this changes, all users' layouts would be reset to the
+      // default layout.
+      self.customizationIdentifier = [kTouchBarBaseIdentifier
+          stringByAppendingPathExtension:@"defaultbar"];
+      nsCOMPtr<nsIArray> allItems;
+
+      nsresult rv = mTouchBarHelper->GetAllItems(getter_AddRefs(allItems));
+      if (NS_FAILED(rv) || !allItems) {
+        return nil;
+      }
+
+      uint32_t itemCount = 0;
+      allItems->GetLength(&itemCount);
+      // This is copied to self.customizationAllowedItemIdentifiers.
+      // Required since [self.mappedItems allKeys] does not preserve order.
+      // One slot is added for the spacer item.
+      NSMutableArray* orderedIdentifiers =
+          [NSMutableArray arrayWithCapacity:itemCount + 1];
+      for (uint32_t i = 0; i < itemCount; ++i) {
+        nsCOMPtr<nsITouchBarInput> input = do_QueryElementAt(allItems, i);
+        if (!input) {
+          continue;
+        }
+
+        TouchBarInput* convertedInput;
+        NSTouchBarItemIdentifier newInputIdentifier =
+            [TouchBarInput nativeIdentifierWithXPCOM:input];
+        if (!newInputIdentifier) {
+          continue;
+        }
+
+        // If there is already an input in mappedLayoutItems with this
+        // identifier, that means updateItem fired before this initialization.
+        // The input cached by updateItem is more current, so we should use that
+        // one.
+        if (self.mappedLayoutItems[newInputIdentifier]) {
+          convertedInput = self.mappedLayoutItems[newInputIdentifier];
+        } else {
+          convertedInput = [[TouchBarInput alloc] initWithXPCOM:input];
+          // Add new input to dictionary for lookup of properties in delegate.
+          self.mappedLayoutItems[[convertedInput nativeIdentifier]] =
+              convertedInput;
+        }
+
+        orderedIdentifiers[i] = [convertedInput nativeIdentifier];
+      }
+      [orderedIdentifiers addObject:@"NSTouchBarItemIdentifierFlexibleSpace"];
+      self.customizationAllowedItemIdentifiers = [orderedIdentifiers copy];
+
+      NSArray* defaultItemIdentifiers = @[
+        [TouchBarInput nativeIdentifierWithType:@"button" withKey:@"back"],
+        [TouchBarInput nativeIdentifierWithType:@"button" withKey:@"forward"],
+        [TouchBarInput nativeIdentifierWithType:@"button" withKey:@"reload"],
+        [TouchBarInput nativeIdentifierWithType:@"mainButton"
+                                        withKey:@"open-location"],
+        [TouchBarInput nativeIdentifierWithType:@"button" withKey:@"new-tab"],
+        [TouchBarInput shareScrubberIdentifier],
+        [TouchBarInput searchPopoverIdentifier]
+      ];
+      self.defaultItemIdentifiers = [defaultItemIdentifiers copy];
+    } else {
+      NSMutableArray* defaultItemIdentifiers =
+          [NSMutableArray arrayWithCapacity:[aInputs count]];
+      for (TouchBarInput* input in aInputs) {
+        self.mappedLayoutItems[[input nativeIdentifier]] = input;
+        [defaultItemIdentifiers addObject:[input nativeIdentifier]];
+      }
+      self.defaultItemIdentifiers = [defaultItemIdentifiers copy];
+    }
+  }
+
+  return self;
+}
+
+- (void)dealloc {
+  for (NSTouchBarItemIdentifier identifier in self.mappedLayoutItems) {
+    NSTouchBarItem* item = [self itemForIdentifier:identifier];
+    if (!item) {
+      continue;
+    }
+    if ([item isKindOfClass:[NSPopoverTouchBarItem class]]) {
+      [(NSPopoverTouchBarItem*)item setCollapsedRepresentationImage:nil];
+      [(nsTouchBar*)[(NSPopoverTouchBarItem*)item popoverTouchBar] release];
+    } else if ([[item view] isKindOfClass:[NSScrollView class]]) {
+      [[(NSScrollView*)[item view] documentView] release];
+      [(NSScrollView*)[item view] release];
+    }
+
+    [item release];
+  }
+
+  [self.defaultItemIdentifiers release];
+  [self.customizationAllowedItemIdentifiers release];
+  [self.scrollViewButtons removeAllObjects];
+  [self.scrollViewButtons release];
+  [self.mappedLayoutItems removeAllObjects];
+  [self.mappedLayoutItems release];
+  [super dealloc];
+}
+
+- (NSTouchBarItem*)touchBar:(NSTouchBar*)aTouchBar
+      makeItemForIdentifier:(NSTouchBarItemIdentifier)aIdentifier {
+  if (!mTouchBarHelper) {
+    return nil;
+  }
+
+  TouchBarInput* input = self.mappedLayoutItems[aIdentifier];
+  if (!input) {
+    return nil;
+  }
+
+  if ([input baseType] == TouchBarInputBaseType::kScrubber) {
+    // We check the identifier rather than the baseType here as a special case.
+    if (![aIdentifier
+            isEqualToString:[TouchBarInput shareScrubberIdentifier]]) {
+      // We're only supporting the Share scrubber for now.
+      return nil;
+    }
+    return [self makeShareScrubberForIdentifier:aIdentifier];
+  }
+
+  if ([input baseType] == TouchBarInputBaseType::kPopover) {
+    NSPopoverTouchBarItem* newPopoverItem =
+        [[NSPopoverTouchBarItem alloc] initWithIdentifier:aIdentifier];
+    [newPopoverItem setCustomizationLabel:[input title]];
+    // We initialize popoverTouchBar here because we only allow setting this
+    // property on popover creation. Updating popoverTouchBar for every update
+    // of the popover item would be very expensive.
+    newPopoverItem.popoverTouchBar =
+        [[nsTouchBar alloc] initWithInputs:[input children]];
+    [self updatePopover:newPopoverItem withIdentifier:[input nativeIdentifier]];
+    return newPopoverItem;
+  }
+
+  // Our new item, which will be initialized depending on aIdentifier.
+  NSCustomTouchBarItem* newItem =
+      [[NSCustomTouchBarItem alloc] initWithIdentifier:aIdentifier];
+  [newItem setCustomizationLabel:[input title]];
+
+  if ([input baseType] == TouchBarInputBaseType::kScrollView) {
+    [self updateScrollView:newItem withIdentifier:[input nativeIdentifier]];
+    return newItem;
+  } else if ([input baseType] == TouchBarInputBaseType::kLabel) {
+    NSTextField* label = [NSTextField labelWithString:@""];
+    [self updateLabel:label withIdentifier:[input nativeIdentifier]];
+    newItem.view = label;
+    return newItem;
+  }
+
+  // The cases of a button or main button require the same setup.
+  NSButton* button = [NSButton buttonWithTitle:@""
+                                        target:self
+                                        action:@selector(touchBarAction:)];
+  newItem.view = button;
+
+  if ([input baseType] == TouchBarInputBaseType::kButton &&
+      ![[input type] hasPrefix:@"scrollView"]) {
+    [self updateButton:newItem withIdentifier:[input nativeIdentifier]];
+  } else if ([input baseType] == TouchBarInputBaseType::kMainButton) {
+    [self updateMainButton:newItem withIdentifier:[input nativeIdentifier]];
+  }
+  return newItem;
+}
+
+- (bool)updateItem:(TouchBarInput*)aInput {
+  if (!mTouchBarHelper) {
+    return false;
+  }
+
+  NSTouchBarItem* item = [self itemForIdentifier:[aInput nativeIdentifier]];
+
+  // If we can't immediately find item, there are three possibilities:
+  //   * It is a button in a ScrollView, or
+  //   * It is contained within a popover, or
+  //   * It simply does not exist.
+  // We check for each possibility here.
+  if (!self.mappedLayoutItems[[aInput nativeIdentifier]]) {
+    if ([self maybeUpdateScrollViewChild:aInput]) {
+      return true;
+    }
+    if ([self maybeUpdatePopoverChild:aInput]) {
+      return true;
+    }
+    return false;
+  }
+
+  // Update our canonical copy of the input.
+  [self replaceMappedLayoutItem:aInput];
+
+  if ([aInput baseType] == TouchBarInputBaseType::kButton) {
+    [(NSCustomTouchBarItem*)item setCustomizationLabel:[aInput title]];
+    [self updateButton:(NSCustomTouchBarItem*)item
+        withIdentifier:[aInput nativeIdentifier]];
+  } else if ([aInput baseType] == TouchBarInputBaseType::kMainButton) {
+    [(NSCustomTouchBarItem*)item setCustomizationLabel:[aInput title]];
+    [self updateMainButton:(NSCustomTouchBarItem*)item
+            withIdentifier:[aInput nativeIdentifier]];
+  } else if ([aInput baseType] == TouchBarInputBaseType::kScrollView) {
+    [(NSCustomTouchBarItem*)item setCustomizationLabel:[aInput title]];
+    [self updateScrollView:(NSCustomTouchBarItem*)item
+            withIdentifier:[aInput nativeIdentifier]];
+  } else if ([aInput baseType] == TouchBarInputBaseType::kPopover) {
+    [(NSPopoverTouchBarItem*)item setCustomizationLabel:[aInput title]];
+    [self updatePopover:(NSPopoverTouchBarItem*)item
+         withIdentifier:[aInput nativeIdentifier]];
+    for (TouchBarInput* child in [aInput children]) {
+      [(nsTouchBar*)[(NSPopoverTouchBarItem*)item popoverTouchBar]
+          updateItem:child];
+    }
+  } else if ([aInput baseType] == TouchBarInputBaseType::kLabel) {
+    [self updateLabel:(NSTextField*)item.view
+        withIdentifier:[aInput nativeIdentifier]];
+  }
+
+  return true;
+}
+
+- (bool)maybeUpdatePopoverChild:(TouchBarInput*)aInput {
+  for (NSTouchBarItemIdentifier identifier in self.mappedLayoutItems) {
+    TouchBarInput* potentialPopover = self.mappedLayoutItems[identifier];
+    if ([potentialPopover baseType] != TouchBarInputBaseType::kPopover) {
+      continue;
+    }
+    NSTouchBarItem* popover =
+        [self itemForIdentifier:[potentialPopover nativeIdentifier]];
+    if (popover) {
+      if ([(nsTouchBar*)[(NSPopoverTouchBarItem*)popover popoverTouchBar]
+              updateItem:aInput]) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+- (bool)maybeUpdateScrollViewChild:(TouchBarInput*)aInput {
+  NSCustomTouchBarItem* scrollViewButton =
+      self.scrollViewButtons[[aInput nativeIdentifier]];
+  if (scrollViewButton) {
+    // ScrollView buttons are similar to mainButtons except for their width.
+    [self updateMainButton:scrollViewButton
+            withIdentifier:[aInput nativeIdentifier]];
+    NSButton* button = (NSButton*)scrollViewButton.view;
+    uint32_t buttonSize =
+        MAX(button.attributedTitle.size.width + kInputIconSize + kInputSpacing,
+            kScrollViewButtonWidth);
+    [[button widthAnchor] constraintGreaterThanOrEqualToConstant:buttonSize]
+        .active = YES;
+  }
+  // Updating the TouchBarInput* in the ScrollView's mChildren array.
+  for (NSTouchBarItemIdentifier identifier in self.mappedLayoutItems) {
+    TouchBarInput* potentialScrollView = self.mappedLayoutItems[identifier];
+    if ([potentialScrollView baseType] != TouchBarInputBaseType::kScrollView) {
+      continue;
+    }
+    for (uint32_t i = 0; i < [[potentialScrollView children] count]; ++i) {
+      TouchBarInput* child = [potentialScrollView children][i];
+      if (![[child nativeIdentifier]
+              isEqualToString:[aInput nativeIdentifier]]) {
+        continue;
+      }
+      [[potentialScrollView children] replaceObjectAtIndex:i withObject:aInput];
+      [child release];
+      return true;
+    }
+  }
+  return false;
+}
+
+- (void)replaceMappedLayoutItem:(TouchBarInput*)aItem {
+  [self.mappedLayoutItems[[aItem nativeIdentifier]] release];
+  self.mappedLayoutItems[[aItem nativeIdentifier]] = aItem;
+}
+
+- (void)updateButton:(NSCustomTouchBarItem*)aButton
+      withIdentifier:(NSTouchBarItemIdentifier)aIdentifier {
+  if (!aButton || !aIdentifier) {
+    return;
+  }
+
+  TouchBarInput* input = self.mappedLayoutItems[aIdentifier];
+  if (!input) {
+    return;
+  }
+
+  NSButton* button = (NSButton*)[aButton view];
+  button.title = [input title];
+  if ([input imageURI]) {
+    [button setImagePosition:NSImageOnly];
+    [self loadIconForInput:input forItem:aButton];
+    // Because we are hiding the title, NSAccessibility also does not get it.
+    // Therefore, set an accessibility label as alternative text for image-only
+    // buttons.
+    [button setAccessibilityLabel:[input title]];
+  }
+
+  [button setEnabled:![input isDisabled]];
+  if ([input color]) {
+    button.bezelColor = [input color];
+  }
+
+  objc_setAssociatedObject(button, &sIdentifierAssociationKey, aIdentifier,
+                           OBJC_ASSOCIATION_RETAIN);
+}
+
+- (void)updateMainButton:(NSCustomTouchBarItem*)aMainButton
+          withIdentifier:(NSTouchBarItemIdentifier)aIdentifier {
+  if (!aMainButton || !aIdentifier) {
+    return;
+  }
+
+  TouchBarInput* input = self.mappedLayoutItems[aIdentifier];
+  if (!input) {
+    return;
+  }
+
+  [self updateButton:aMainButton withIdentifier:aIdentifier];
+  NSButton* button = (NSButton*)[aMainButton view];
+
+  // If empty, string is still being localized. Display a blank input instead.
+  if ([[input title] isEqualToString:@""]) {
+    [button setImagePosition:NSNoImage];
+  } else {
+    [button setImagePosition:NSImageLeft];
+  }
+  button.imageHugsTitle = YES;
+  [button.widthAnchor constraintGreaterThanOrEqualToConstant:MAIN_BUTTON_WIDTH]
+      .active = YES;
+  [button setContentHuggingPriority:1.0
+                     forOrientation:NSLayoutConstraintOrientationHorizontal];
+}
+
+- (void)updatePopover:(NSPopoverTouchBarItem*)aPopoverItem
+       withIdentifier:(NSTouchBarItemIdentifier)aIdentifier {
+  if (!aPopoverItem || !aIdentifier) {
+    return;
+  }
+
+  TouchBarInput* input = self.mappedLayoutItems[aIdentifier];
+  if (!input) {
+    return;
+  }
+
+  aPopoverItem.showsCloseButton = YES;
+  if ([input imageURI]) {
+    [self loadIconForInput:input forItem:aPopoverItem];
+  } else if ([input title]) {
+    aPopoverItem.collapsedRepresentationLabel = [input title];
+  }
+
+  // Special handling to show/hide the search popover if the Urlbar is focused.
+  if ([[input nativeIdentifier]
+          isEqualToString:[TouchBarInput searchPopoverIdentifier]]) {
+    // We can reach this code during window shutdown. We only want to toggle
+    // showPopover if we are in a normal running state.
+    if (!mTouchBarHelper) {
+      return;
+    }
+    bool urlbarIsFocused = false;
+    mTouchBarHelper->GetIsUrlbarFocused(&urlbarIsFocused);
+    if (urlbarIsFocused) {
+      [aPopoverItem showPopover:self];
+    }
+  }
+}
+
+- (void)updateScrollView:(NSCustomTouchBarItem*)aScrollViewItem
+          withIdentifier:(NSTouchBarItemIdentifier)aIdentifier {
+  if (!aScrollViewItem || !aIdentifier) {
+    return;
+  }
+
+  TouchBarInput* input = self.mappedLayoutItems[aIdentifier];
+  if (!input || ![input children]) {
+    return;
+  }
+
+  NSMutableDictionary* constraintViews = [NSMutableDictionary dictionary];
+  NSView* documentView = [[NSView alloc] initWithFrame:NSZeroRect];
+  NSString* layoutFormat = @"H:|-8-";
+  NSSize size = NSMakeSize(kInputSpacing, 30);
+  // Layout strings allow only alphanumeric characters. We will use this
+  // NSCharacterSet to strip illegal characters.
+  NSCharacterSet* charactersToRemove =
+      [[NSCharacterSet alphanumericCharacterSet] invertedSet];
+
+  for (TouchBarInput* childInput in [input children]) {
+    if ([childInput baseType] != TouchBarInputBaseType::kButton) {
+      continue;
+    }
+    [self replaceMappedLayoutItem:childInput];
+    NSCustomTouchBarItem* newItem = [[NSCustomTouchBarItem alloc]
+        initWithIdentifier:[childInput nativeIdentifier]];
+    NSButton* button = [NSButton buttonWithTitle:[childInput title]
+                                          target:self
+                                          action:@selector(touchBarAction:)];
+    newItem.view = button;
+    // ScrollView buttons are similar to mainButtons except for their width.
+    [self updateMainButton:newItem
+            withIdentifier:[childInput nativeIdentifier]];
+    uint32_t buttonSize =
+        MAX(button.attributedTitle.size.width + kInputIconSize + kInputSpacing,
+            kScrollViewButtonWidth);
+    [[button widthAnchor] constraintGreaterThanOrEqualToConstant:buttonSize]
+        .active = YES;
+
+    NSCustomTouchBarItem* tempItem =
+        self.scrollViewButtons[[childInput nativeIdentifier]];
+    self.scrollViewButtons[[childInput nativeIdentifier]] = newItem;
+    [tempItem release];
+
+    button.translatesAutoresizingMaskIntoConstraints = NO;
+    [documentView addSubview:button];
+    NSString* layoutKey = [[[childInput nativeIdentifier]
+        componentsSeparatedByCharactersInSet:charactersToRemove]
+        componentsJoinedByString:@""];
+
+    // Iteratively create our layout string.
+    layoutFormat = [layoutFormat
+        stringByAppendingString:[NSString
+                                    stringWithFormat:@"[%@]-8-", layoutKey]];
+    [constraintViews setObject:button forKey:layoutKey];
+    size.width += kInputSpacing + buttonSize;
+  }
+  layoutFormat =
+      [layoutFormat stringByAppendingString:[NSString stringWithFormat:@"|"]];
+  NSArray* hConstraints = [NSLayoutConstraint
+      constraintsWithVisualFormat:layoutFormat
+                          options:NSLayoutFormatAlignAllCenterY
+                          metrics:nil
+                            views:constraintViews];
+  NSScrollView* scrollView = [[NSScrollView alloc]
+      initWithFrame:CGRectMake(0, 0, size.width, size.height)];
+  [documentView setFrame:NSMakeRect(0, 0, size.width, size.height)];
+  [NSLayoutConstraint activateConstraints:hConstraints];
+  scrollView.documentView = documentView;
+
+  aScrollViewItem.view = scrollView;
+}
+
+- (void)updateLabel:(NSTextField*)aLabel
+     withIdentifier:(NSTouchBarItemIdentifier)aIdentifier {
+  if (!aLabel || !aIdentifier) {
+    return;
+  }
+
+  TouchBarInput* input = self.mappedLayoutItems[aIdentifier];
+  if (!input || ![input title]) {
+    return;
+  }
+  [aLabel setStringValue:[input title]];
+}
+
+- (NSTouchBarItem*)makeShareScrubberForIdentifier:
+    (NSTouchBarItemIdentifier)aIdentifier {
+  TouchBarInput* input = self.mappedLayoutItems[aIdentifier];
+  // System-default share menu
+  NSSharingServicePickerTouchBarItem* servicesItem =
+      [[NSSharingServicePickerTouchBarItem alloc]
+          initWithIdentifier:aIdentifier];
+
+  // buttonImage needs to be set to nil while we wait for our icon to load.
+  // Otherwise, the default Apple share icon is automatically loaded.
+  servicesItem.buttonImage = nil;
+
+  [self loadIconForInput:input forItem:servicesItem];
+
+  servicesItem.delegate = self;
+  return servicesItem;
+}
+
+- (void)showPopover:(TouchBarInput*)aPopover showing:(bool)aShowing {
+  if (!aPopover) {
+    return;
+  }
+  NSPopoverTouchBarItem* popoverItem = (NSPopoverTouchBarItem*)[self
+      itemForIdentifier:[aPopover nativeIdentifier]];
+  if (!popoverItem) {
+    return;
+  }
+  if (aShowing) {
+    [popoverItem showPopover:self];
+  } else {
+    [popoverItem dismissPopover:self];
+  }
+}
+
+- (void)touchBarAction:(id)aSender {
+  NSTouchBarItemIdentifier identifier =
+      objc_getAssociatedObject(aSender, &sIdentifierAssociationKey);
+  if (!identifier || [identifier isEqualToString:@""]) {
+    return;
+  }
+
+  TouchBarInput* input = self.mappedLayoutItems[identifier];
+  if (!input) {
+    return;
+  }
+
+  nsCOMPtr<nsITouchBarInputCallback> callback = [input callback];
+  if (!callback) {
+    NSLog(@"Touch Bar action attempted with no valid callback! Identifier: %@",
+          [input nativeIdentifier]);
+    return;
+  }
+  callback->OnCommand();
+}
+
+- (void)loadIconForInput:(TouchBarInput*)aInput forItem:(NSTouchBarItem*)aItem {
+  if (!aInput || ![aInput imageURI] || !aItem || !mTouchBarHelper) {
+    return;
+  }
+
+  RefPtr<nsTouchBarInputIcon> icon = [aInput icon];
+
+  if (!icon) {
+    RefPtr<Document> document;
+    nsresult rv = mTouchBarHelper->GetDocument(getter_AddRefs(document));
+    if (NS_FAILED(rv) || !document) {
+      return;
+    }
+    icon = new nsTouchBarInputIcon(document, aInput, aItem);
+    [aInput setIcon:icon];
+  }
+  icon->SetupIcon([aInput imageURI]);
+}
+
+- (void)releaseJSObjects {
+  mTouchBarHelper = nil;
+
+  for (NSTouchBarItemIdentifier identifier in self.mappedLayoutItems) {
+    TouchBarInput* input = self.mappedLayoutItems[identifier];
+    if (!input) {
+      continue;
+    }
+
+    // Childless popovers contain the default Touch Bar as its popoverTouchBar.
+    // We check for [input children] since the default Touch Bar contains a
+    // popover (search-popover), so this would infinitely loop if there was no
+    // check.
+    if ([input baseType] == TouchBarInputBaseType::kPopover &&
+        [input children]) {
+      NSTouchBarItem* item = [self itemForIdentifier:identifier];
+      [(nsTouchBar*)[(NSPopoverTouchBarItem*)item popoverTouchBar]
+          releaseJSObjects];
+    }
+
+    [input releaseJSObjects];
+  }
+}
+
+#pragma mark - NSSharingServicePickerTouchBarItemDelegate
+
+- (NSArray*)itemsForSharingServicePickerTouchBarItem:
+    (NSSharingServicePickerTouchBarItem*)aPickerTouchBarItem {
+  NSURL* urlToShare = nil;
+  NSString* titleToShare = @"";
+  nsAutoString url;
+  nsAutoString title;
+  if (mTouchBarHelper) {
+    nsresult rv = mTouchBarHelper->GetActiveUrl(url);
+    if (!NS_FAILED(rv)) {
+      urlToShare = [NSURL URLWithString:nsCocoaUtils::ToNSString(url)];
+      // NSURL URLWithString returns nil if the URL is invalid. At this point,
+      // it is too late to simply shut down the share menu, so we default to
+      // about:blank if the share button is clicked when the URL is invalid.
+      if (urlToShare == nil) {
+        urlToShare = [NSURL URLWithString:@"about:blank"];
+      }
+    }
+
+    rv = mTouchBarHelper->GetActiveTitle(title);
+    if (!NS_FAILED(rv)) {
+      titleToShare = nsCocoaUtils::ToNSString(title);
+    }
+  }
+
+  return @[ urlToShare, titleToShare ];
+}
+
+- (NSArray<NSSharingService*>*)
+       sharingServicePicker:(NSSharingServicePicker*)aSharingServicePicker
+    sharingServicesForItems:(NSArray*)aItems
+    proposedSharingServices:(NSArray<NSSharingService*>*)aProposedServices {
+  // redundant services
+  NSArray* excludedServices = @[
+    @"com.apple.share.System.add-to-safari-reading-list",
+  ];
+
+  NSArray* sharingServices = [aProposedServices
+      filteredArrayUsingPredicate:[NSPredicate
+                                      predicateWithFormat:@"NOT (name IN %@)",
+                                                          excludedServices]];
+
+  return sharingServices;
+}
+
+@end
diff --git a/widget/cocoa/nsTouchBarInput.h b/widget/cocoa/nsTouchBarInput.h
new file mode 100644
index 0000000000..41ed7979a4
--- /dev/null
+++ b/widget/cocoa/nsTouchBarInput.h
@@ -0,0 +1,91 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsTouchBarInput_h_
+#define nsTouchBarInput_h_
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsITouchBarInput.h"
+#include "nsCOMPtr.h"
+
+using namespace mozilla::dom;
+
+enum class TouchBarInputBaseType : uint8_t {
+  kButton,
+  kLabel,
+  kMainButton,
+  kPopover,
+  kScrollView,
+  kScrubber
+};
+
+class nsTouchBarInputIcon;
+
+/**
+ * NSObject representation of nsITouchBarInput.
+ */
+@interface TouchBarInput : NSObject {
+  nsCOMPtr<nsIURI> mImageURI;
+  RefPtr<nsTouchBarInputIcon> mIcon;
+  TouchBarInputBaseType mBaseType;
+  NSString* mType;
+  nsCOMPtr<nsITouchBarInputCallback> mCallback;
+  NSMutableArray<TouchBarInput*>* mChildren;
+}
+
+@property(strong) NSString* key;
+@property(strong) NSString* type;
+@property(strong) NSString* title;
+@property(strong) NSColor* color;
+@property(nonatomic, getter=isDisabled) BOOL disabled;
+
+- (nsCOMPtr<nsIURI>)imageURI;
+- (RefPtr<nsTouchBarInputIcon>)icon;
+- (TouchBarInputBaseType)baseType;
+- (NSTouchBarItemIdentifier)nativeIdentifier;
+- (nsCOMPtr<nsITouchBarInputCallback>)callback;
+- (NSMutableArray<TouchBarInput*>*)children;
+- (void)setImageURI:(nsCOMPtr<nsIURI>)aImageURI;
+- (void)setIcon:(RefPtr<nsTouchBarInputIcon>)aIcon;
+- (void)setCallback:(nsCOMPtr<nsITouchBarInputCallback>)aCallback;
+- (void)setChildren:(NSMutableArray<TouchBarInput*>*)aChildren;
+
+- (id)initWithKey:(NSString*)aKey
+            title:(NSString*)aTitle
+         imageURI:(nsCOMPtr<nsIURI>)aImageURI
+             type:(NSString*)aType
+         callback:(nsCOMPtr<nsITouchBarInputCallback>)aCallback
+            color:(uint32_t)aColor
+         disabled:(BOOL)aDisabled
+         children:(nsCOMPtr<nsIArray>)aChildren;
+
+- (TouchBarInput*)initWithXPCOM:(nsCOMPtr<nsITouchBarInput>)aInput;
+
+- (void)releaseJSObjects;
+
+- (void)dealloc;
+
+/**
+ * We make these helper methods static so that other classes can query a
+ * TouchBarInput's nativeIdentifier (e.g. nsTouchBarUpdater looking up a
+ * popover in mappedLayoutItems).
+ */
++ (NSTouchBarItemIdentifier)nativeIdentifierWithType:(NSString*)aType
+                                             withKey:(NSString*)aKey;
++ (NSTouchBarItemIdentifier)nativeIdentifierWithXPCOM:
+    (nsCOMPtr<nsITouchBarInput>)aInput;
+
+// Non-JS scrubber implemention for the Share Scrubber,
+// since it is defined by an Apple API.
++ (NSTouchBarItemIdentifier)shareScrubberIdentifier;
+
+// The search popover needs to show/hide depending on if the Urlbar is focused
+// when it is created. We keep track of its identifier to accommodate this
+// special handling.
++ (NSTouchBarItemIdentifier)searchPopoverIdentifier;
+
+@end
+
+#endif  // nsTouchBarInput_h_
diff --git a/widget/cocoa/nsTouchBarInput.mm b/widget/cocoa/nsTouchBarInput.mm
new file mode 100644
index 0000000000..af638f52d3
--- /dev/null
+++ b/widget/cocoa/nsTouchBarInput.mm
@@ -0,0 +1,251 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsTouchBarInput.h"
+
+#include "mozilla/MacStringHelpers.h"
+#include "nsArrayUtils.h"
+#include "nsCocoaUtils.h"
+#include "nsTouchBar.h"
+#include "nsTouchBarInputIcon.h"
+
+@implementation TouchBarInput
+
+- (nsCOMPtr<nsIURI>)imageURI {
+  return mImageURI;
+}
+
+- (void)setImageURI:(nsCOMPtr<nsIURI>)aImageURI {
+  mImageURI = aImageURI;
+}
+
+- (RefPtr<nsTouchBarInputIcon>)icon {
+  return mIcon;
+}
+
+- (void)setIcon:(RefPtr<nsTouchBarInputIcon>)aIcon {
+  mIcon = aIcon;
+}
+
+- (TouchBarInputBaseType)baseType {
+  return mBaseType;
+}
+
+- (NSString*)type {
+  return mType;
+}
+
+- (void)setType:(NSString*)aType {
+  [aType retain];
+  [mType release];
+  if ([aType hasSuffix:@"button"]) {
+    mBaseType = TouchBarInputBaseType::kButton;
+  } else if ([aType hasSuffix:@"label"]) {
+    mBaseType = TouchBarInputBaseType::kLabel;
+  } else if ([aType hasSuffix:@"mainButton"]) {
+    mBaseType = TouchBarInputBaseType::kMainButton;
+  } else if ([aType hasSuffix:@"popover"]) {
+    mBaseType = TouchBarInputBaseType::kPopover;
+  } else if ([aType hasSuffix:@"scrollView"]) {
+    mBaseType = TouchBarInputBaseType::kScrollView;
+  } else if ([aType hasSuffix:@"scrubber"]) {
+    mBaseType = TouchBarInputBaseType::kScrubber;
+  }
+  mType = aType;
+}
+
+- (NSTouchBarItemIdentifier)nativeIdentifier {
+  return [TouchBarInput nativeIdentifierWithType:mType withKey:self.key];
+}
+
+- (nsCOMPtr<nsITouchBarInputCallback>)callback {
+  return mCallback;
+}
+
+- (void)setCallback:(nsCOMPtr<nsITouchBarInputCallback>)aCallback {
+  mCallback = aCallback;
+}
+
+- (NSMutableArray<TouchBarInput*>*)children {
+  return mChildren;
+}
+
+- (void)setChildren:(NSMutableArray<TouchBarInput*>*)aChildren {
+  [aChildren retain];
+  for (TouchBarInput* child in mChildren) {
+    [child releaseJSObjects];
+  }
+  [mChildren removeAllObjects];
+  [mChildren release];
+  mChildren = aChildren;
+}
+
+- (id)initWithKey:(NSString*)aKey
+            title:(NSString*)aTitle
+         imageURI:(nsCOMPtr<nsIURI>)aImageURI
+             type:(NSString*)aType
+         callback:(nsCOMPtr<nsITouchBarInputCallback>)aCallback
+            color:(uint32_t)aColor
+         disabled:(BOOL)aDisabled
+         children:(nsCOMPtr<nsIArray>)aChildren {
+  if (self = [super init]) {
+    mType = nil;
+
+    self.key = aKey;
+    self.title = aTitle;
+    self.type = aType;
+    self.disabled = aDisabled;
+    [self setImageURI:aImageURI];
+    [self setCallback:aCallback];
+    if (aColor) {
+      [self setColor:[NSColor
+                         colorWithDisplayP3Red:((aColor >> 16) & 0xFF) / 255.0
+                                         green:((aColor >> 8) & 0xFF) / 255.0
+                                          blue:((aColor) & 0xFF) / 255.0
+                                         alpha:1.0]];
+    }
+    if (aChildren) {
+      uint32_t itemCount = 0;
+      aChildren->GetLength(&itemCount);
+      NSMutableArray* orderedChildren =
+          [NSMutableArray arrayWithCapacity:itemCount];
+      for (uint32_t i = 0; i < itemCount; ++i) {
+        nsCOMPtr<nsITouchBarInput> child = do_QueryElementAt(aChildren, i);
+        if (!child) {
+          continue;
+        }
+        TouchBarInput* convertedChild =
+            [[TouchBarInput alloc] initWithXPCOM:child];
+        if (convertedChild) {
+          orderedChildren[i] = convertedChild;
+        }
+      }
+      [self setChildren:orderedChildren];
+    }
+  }
+
+  return self;
+}
+
+- (TouchBarInput*)initWithXPCOM:(nsCOMPtr<nsITouchBarInput>)aInput {
+  nsAutoString keyStr;
+  nsresult rv = aInput->GetKey(keyStr);
+  if (NS_FAILED(rv)) {
+    return nil;
+  }
+
+  nsAutoString titleStr;
+  rv = aInput->GetTitle(titleStr);
+  if (NS_FAILED(rv)) {
+    return nil;
+  }
+
+  nsCOMPtr<nsIURI> imageURI;
+  rv = aInput->GetImage(getter_AddRefs(imageURI));
+  if (NS_FAILED(rv)) {
+    return nil;
+  }
+
+  nsAutoString typeStr;
+  rv = aInput->GetType(typeStr);
+  if (NS_FAILED(rv)) {
+    return nil;
+  }
+
+  nsCOMPtr<nsITouchBarInputCallback> callback;
+  rv = aInput->GetCallback(getter_AddRefs(callback));
+  if (NS_FAILED(rv)) {
+    return nil;
+  }
+
+  uint32_t colorInt;
+  rv = aInput->GetColor(&colorInt);
+  if (NS_FAILED(rv)) {
+    return nil;
+  }
+
+  bool disabled = false;
+  rv = aInput->GetDisabled(&disabled);
+  if (NS_FAILED(rv)) {
+    return nil;
+  }
+
+  nsCOMPtr<nsIArray> children;
+  rv = aInput->GetChildren(getter_AddRefs(children));
+  if (NS_FAILED(rv)) {
+    return nil;
+  }
+
+  return [self initWithKey:nsCocoaUtils::ToNSString(keyStr)
+                     title:nsCocoaUtils::ToNSString(titleStr)
+                  imageURI:imageURI
+                      type:nsCocoaUtils::ToNSString(typeStr)
+                  callback:callback
+                     color:colorInt
+                  disabled:(BOOL)disabled
+                  children:children];
+}
+
+- (void)releaseJSObjects {
+  if (mIcon) {
+    mIcon->Destroy();
+    mIcon = nil;
+  }
+  [self setCallback:nil];
+  [self setImageURI:nil];
+  for (TouchBarInput* child in mChildren) {
+    [child releaseJSObjects];
+  }
+}
+
+- (void)dealloc {
+  if (mIcon) {
+    mIcon->Destroy();
+    mIcon = nil;
+  }
+  [mType release];
+  [mChildren removeAllObjects];
+  [mChildren release];
+  [super dealloc];
+}
+
++ (NSTouchBarItemIdentifier)nativeIdentifierWithType:(NSString*)aType
+                                             withKey:(NSString*)aKey {
+  NSTouchBarItemIdentifier identifier;
+  identifier = [kTouchBarBaseIdentifier stringByAppendingPathExtension:aType];
+  if (aKey) {
+    identifier = [identifier stringByAppendingPathExtension:aKey];
+  }
+  return identifier;
+}
+
++ (NSTouchBarItemIdentifier)nativeIdentifierWithXPCOM:
+    (nsCOMPtr<nsITouchBarInput>)aInput {
+  nsAutoString keyStr;
+  nsresult rv = aInput->GetKey(keyStr);
+  if (NS_FAILED(rv)) {
+    return nil;
+  }
+  NSString* key = nsCocoaUtils::ToNSString(keyStr);
+
+  nsAutoString typeStr;
+  rv = aInput->GetType(typeStr);
+  if (NS_FAILED(rv)) {
+    return nil;
+  }
+  NSString* type = nsCocoaUtils::ToNSString(typeStr);
+
+  return [TouchBarInput nativeIdentifierWithType:type withKey:key];
+}
+
++ (NSTouchBarItemIdentifier)shareScrubberIdentifier {
+  return [TouchBarInput nativeIdentifierWithType:@"scrubber" withKey:@"share"];
+}
+
++ (NSTouchBarItemIdentifier)searchPopoverIdentifier {
+  return [TouchBarInput nativeIdentifierWithType:@"popover"
+                                         withKey:@"search-popover"];
+}
+
+@end
diff --git a/widget/cocoa/nsTouchBarInputIcon.h b/widget/cocoa/nsTouchBarInputIcon.h
new file mode 100644
index 0000000000..d018afb756
--- /dev/null
+++ b/widget/cocoa/nsTouchBarInputIcon.h
@@ -0,0 +1,70 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Retrieves and displays icons on the macOS Touch Bar.
+ */
+
+#ifndef nsTouchBarInputIcon_h_
+#define nsTouchBarInputIcon_h_
+
+#import <Cocoa/Cocoa.h>
+
+#include "mozilla/widget/IconLoader.h"
+#include "nsTouchBarInput.h"
+
+using namespace mozilla::dom;
+
+class nsIURI;
+class nsIPrincipal;
+class imgRequestProxy;
+
+namespace mozilla::dom {
+class Document;
+}
+
+class nsTouchBarInputIcon : public mozilla::widget::IconLoader::Listener {
+ public:
+  explicit nsTouchBarInputIcon(RefPtr<Document> aDocument,
+                               TouchBarInput* aInput, NSTouchBarItem* aItem);
+
+  NS_INLINE_DECL_REFCOUNTING(nsTouchBarInputIcon)
+
+ private:
+  virtual ~nsTouchBarInputIcon();
+
+ public:
+  // SetupIcon succeeds if it was able to set up the icon, or if there should
+  // be no icon, in which case it clears any existing icon but still succeeds.
+  nsresult SetupIcon(nsCOMPtr<nsIURI> aIconURI);
+
+  // Implements this method for mozilla::widget::IconLoader::Listener.
+  // Called once the icon load is complete.
+  nsresult OnComplete(imgIContainer* aImage) override;
+
+  // Unless we take precautions, we may outlive the object that created us
+  // (mTouchBar, which owns our native menu item (mTouchBarInput)).
+  // Destroy() should be called from mTouchBar's destructor to prevent
+  // this from happening.
+  void Destroy();
+
+  void ReleaseJSObjects();
+
+ protected:
+  RefPtr<Document> mDocument;
+  bool mSetIcon;
+  NSButton* mButton;
+  // We accept a mShareScrubber only as a special case since
+  // NSSharingServicePickerTouchBarItem does not expose an NSButton* on which we
+  // can set the `image` property.
+  NSSharingServicePickerTouchBarItem* mShareScrubber;
+  // We accept a popover only as a special case.
+  NSPopoverTouchBarItem* mPopoverItem;
+  // The icon loader object should never outlive its creating
+  // nsTouchBarInputIcon object.
+  RefPtr<mozilla::widget::IconLoader> mIconLoader;
+};
+
+#endif  // nsTouchBarInputIcon_h_
diff --git a/widget/cocoa/nsTouchBarInputIcon.mm b/widget/cocoa/nsTouchBarInputIcon.mm
new file mode 100644
index 0000000000..69e0c2aa0f
--- /dev/null
+++ b/widget/cocoa/nsTouchBarInputIcon.mm
@@ -0,0 +1,141 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Retrieves and displays icons on the macOS Touch Bar.
+ */
+
+#include "nsTouchBarInputIcon.h"
+
+#include "MOZIconHelper.h"
+#include "mozilla/dom/Document.h"
+#include "nsCocoaUtils.h"
+#include "nsComputedDOMStyle.h"
+#include "nsContentUtils.h"
+#include "nsGkAtoms.h"
+#include "nsINode.h"
+#include "nsNameSpaceManager.h"
+#include "nsObjCExceptions.h"
+
+using namespace mozilla;
+using mozilla::widget::IconLoader;
+
+static const uint32_t kIconHeight = 16;
+static const CGFloat kHiDPIScalingFactor = 2.0f;
+
+nsTouchBarInputIcon::nsTouchBarInputIcon(RefPtr<Document> aDocument,
+                                         TouchBarInput* aInput,
+                                         NSTouchBarItem* aItem)
+    : mDocument(aDocument),
+      mSetIcon(false),
+      mButton(nil),
+      mShareScrubber(nil),
+      mPopoverItem(nil) {
+  if ([[aInput nativeIdentifier]
+          isEqualToString:[TouchBarInput shareScrubberIdentifier]]) {
+    mShareScrubber = (NSSharingServicePickerTouchBarItem*)aItem;
+  } else if ([aInput baseType] == TouchBarInputBaseType::kPopover) {
+    mPopoverItem = (NSPopoverTouchBarItem*)aItem;
+  } else if ([aInput baseType] == TouchBarInputBaseType::kButton ||
+             [aInput baseType] == TouchBarInputBaseType::kMainButton) {
+    mButton = (NSButton*)[aItem view];
+  } else {
+    NS_ERROR("Incompatible Touch Bar input passed to nsTouchBarInputIcon.");
+  }
+  aInput = nil;
+  MOZ_COUNT_CTOR(nsTouchBarInputIcon);
+}
+
+nsTouchBarInputIcon::~nsTouchBarInputIcon() {
+  Destroy();
+  MOZ_COUNT_DTOR(nsTouchBarInputIcon);
+}
+
+// Called from nsTouchBar's destructor, to prevent us from outliving it
+// (as might otherwise happen if calls to our imgINotificationObserver methods
+// are still outstanding).  nsTouchBar owns our mTouchBarInput.
+void nsTouchBarInputIcon::Destroy() {
+  ReleaseJSObjects();
+  if (mIconLoader) {
+    mIconLoader->Destroy();
+    mIconLoader = nullptr;
+  }
+
+  mButton = nil;
+  mShareScrubber = nil;
+  mPopoverItem = nil;
+}
+
+nsresult nsTouchBarInputIcon::SetupIcon(nsCOMPtr<nsIURI> aIconURI) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  // We might not have a document if the Touch Bar tries to update when the main
+  // window is closed.
+  if (!mDocument) {
+    return NS_OK;
+  }
+
+  if (!(mButton || mShareScrubber || mPopoverItem)) {
+    NS_ERROR("No Touch Bar input provided.");
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!mIconLoader) {
+    mIconLoader = new IconLoader(this);
+  }
+
+  if (!mSetIcon) {
+    // Load placeholder icon.
+    NSSize iconSize = NSMakeSize(kIconHeight, kIconHeight);
+    NSImage* placeholder = [MOZIconHelper placeholderIconWithSize:iconSize];
+    [mButton setImage:placeholder];
+    [mShareScrubber setButtonImage:placeholder];
+    [mPopoverItem setCollapsedRepresentationImage:placeholder];
+  }
+
+  nsresult rv =
+      mIconLoader->LoadIcon(aIconURI, mDocument, true /* aIsInternalIcon */);
+  if (NS_FAILED(rv)) {
+    // There is no icon for this menu item, as an error occurred while loading
+    // it. An icon might have been set earlier or the place holder icon may have
+    // been set.  Clear it.
+    [mButton setImage:nil];
+    [mShareScrubber setButtonImage:nil];
+    [mPopoverItem setCollapsedRepresentationImage:nil];
+  }
+
+  mSetIcon = true;
+
+  return rv;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void nsTouchBarInputIcon::ReleaseJSObjects() { mDocument = nil; }
+
+//
+// mozilla::widget::IconLoader::Listener
+//
+
+nsresult nsTouchBarInputIcon::OnComplete(imgIContainer* aImage) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN
+
+  // We ask only for the HiDPI images since all Touch Bars are Retina
+  // displays and we have no need for icons @1x.
+  NSImage* image = [MOZIconHelper
+      iconImageFromImageContainer:aImage
+                         withSize:NSMakeSize(kIconHeight, kIconHeight)
+                      presContext:nullptr
+                    computedStyle:nullptr
+                      scaleFactor:kHiDPIScalingFactor];
+  [mButton setImage:image];
+  [mShareScrubber setButtonImage:image];
+  [mPopoverItem setCollapsedRepresentationImage:image];
+
+  mIconLoader->Destroy();
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE)
+}
diff --git a/widget/cocoa/nsTouchBarUpdater.h b/widget/cocoa/nsTouchBarUpdater.h
new file mode 100644
index 0000000000..38039f69a0
--- /dev/null
+++ b/widget/cocoa/nsTouchBarUpdater.h
@@ -0,0 +1,23 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsTouchBarUpdater_h_
+#define nsTouchBarUpdater_h_
+
+#include "nsITouchBarUpdater.h"
+#include "nsCocoaWindow.h"
+
+class nsTouchBarUpdater : public nsITouchBarUpdater {
+ public:
+  nsTouchBarUpdater() {}
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITOUCHBARUPDATER
+
+ protected:
+  virtual ~nsTouchBarUpdater() {}
+  BaseWindow* GetCocoaWindow(nsIBaseWindow* aWindow);
+};
+
+#endif  // nsTouchBarUpdater_h_
diff --git a/widget/cocoa/nsTouchBarUpdater.mm b/widget/cocoa/nsTouchBarUpdater.mm
new file mode 100644
index 0000000000..ed0b78c6d1
--- /dev/null
+++ b/widget/cocoa/nsTouchBarUpdater.mm
@@ -0,0 +1,116 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <Cocoa/Cocoa.h>
+
+#include "nsTouchBar.h"
+#include "nsTouchBarInput.h"
+#include "nsTouchBarUpdater.h"
+
+#include "nsIBaseWindow.h"
+#include "nsIWidget.h"
+
+// defined in nsCocoaWindow.mm.
+extern BOOL sTouchBarIsInitialized;
+
+NS_IMPL_ISUPPORTS(nsTouchBarUpdater, nsITouchBarUpdater);
+
+NS_IMETHODIMP
+nsTouchBarUpdater::UpdateTouchBarInputs(
+    nsIBaseWindow* aWindow, const nsTArray<RefPtr<nsITouchBarInput>>& aInputs) {
+  if (!sTouchBarIsInitialized || !aWindow) {
+    return NS_OK;
+  }
+
+  BaseWindow* cocoaWin = nsTouchBarUpdater::GetCocoaWindow(aWindow);
+  if (!cocoaWin) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if ([cocoaWin respondsToSelector:@selector(touchBar)]) {
+    size_t itemCount = aInputs.Length();
+    for (size_t i = 0; i < itemCount; ++i) {
+      nsCOMPtr<nsITouchBarInput> input(aInputs.ElementAt(i));
+      if (!input) {
+        continue;
+      }
+
+      NSTouchBarItemIdentifier newIdentifier =
+          [TouchBarInput nativeIdentifierWithXPCOM:input];
+      // We don't support updating the Share scrubber since it's a special
+      // Apple-made component that behaves differently from the other inputs.
+      if ([newIdentifier
+              isEqualToString:[TouchBarInput
+                                  nativeIdentifierWithType:@"scrubber"
+                                                   withKey:@"share"]]) {
+        continue;
+      }
+
+      TouchBarInput* convertedInput =
+          [[TouchBarInput alloc] initWithXPCOM:input];
+      [(nsTouchBar*)cocoaWin.touchBar updateItem:convertedInput];
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsTouchBarUpdater::ShowPopover(nsIBaseWindow* aWindow,
+                               nsITouchBarInput* aPopover, bool aShowing) {
+  if (!sTouchBarIsInitialized || !aPopover || !aWindow) {
+    return NS_OK;
+  }
+
+  BaseWindow* cocoaWin = nsTouchBarUpdater::GetCocoaWindow(aWindow);
+  if (!cocoaWin) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if ([cocoaWin respondsToSelector:@selector(touchBar)]) {
+    // We don't need to completely reinitialize the popover. We only need its
+    // identifier to look it up in [nsTouchBar mappedLayoutItems].
+    NSTouchBarItemIdentifier popoverIdentifier =
+        [TouchBarInput nativeIdentifierWithXPCOM:aPopover];
+
+    TouchBarInput* popoverItem =
+        [[(nsTouchBar*)cocoaWin.touchBar mappedLayoutItems]
+            objectForKey:popoverIdentifier];
+
+    [(nsTouchBar*)cocoaWin.touchBar showPopover:popoverItem showing:aShowing];
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsTouchBarUpdater::EnterCustomizeMode() {
+  [NSApp toggleTouchBarCustomizationPalette:(id)this];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsTouchBarUpdater::IsTouchBarInitialized(bool* aResult) {
+  *aResult = sTouchBarIsInitialized;
+  return NS_OK;
+}
+
+BaseWindow* nsTouchBarUpdater::GetCocoaWindow(nsIBaseWindow* aWindow) {
+  nsCOMPtr<nsIWidget> widget = nullptr;
+  aWindow->GetMainWidget(getter_AddRefs(widget));
+  if (!widget) {
+    return nil;
+  }
+  BaseWindow* cocoaWin = (BaseWindow*)widget->GetNativeData(NS_NATIVE_WINDOW);
+  if (!cocoaWin) {
+    return nil;
+  }
+  return cocoaWin;
+}
+
+// NOTE: This method is for internal unit tests only.
+NS_IMETHODIMP
+nsTouchBarUpdater::SetTouchBarInitialized(bool aIsInitialized) {
+  sTouchBarIsInitialized = aIsInitialized;
+  return NS_OK;
+}
diff --git a/widget/cocoa/nsUserIdleServiceX.h b/widget/cocoa/nsUserIdleServiceX.h
new file mode 100644
index 0000000000..ff559293e9
--- /dev/null
+++ b/widget/cocoa/nsUserIdleServiceX.h
@@ -0,0 +1,36 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsUserIdleServiceX_h_
+#define nsUserIdleServiceX_h_
+
+#include "nsUserIdleService.h"
+#include "mozilla/AppShutdown.h"
+
+class nsUserIdleServiceX : public nsUserIdleService {
+ public:
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(nsUserIdleServiceX, nsUserIdleService)
+
+  bool PollIdleTime(uint32_t* aIdleTime) override;
+
+  static already_AddRefed<nsUserIdleServiceX> GetInstance() {
+    RefPtr<nsUserIdleService> idleService = nsUserIdleService::GetInstance();
+    if (!idleService) {
+      // Avoid late instantiation or resurrection during shutdown.
+      if (mozilla::AppShutdown::IsInOrBeyond(
+              mozilla::ShutdownPhase::AppShutdownConfirmed)) {
+        return nullptr;
+      }
+      idleService = new nsUserIdleServiceX();
+    }
+
+    return idleService.forget().downcast<nsUserIdleServiceX>();
+  }
+
+ protected:
+  nsUserIdleServiceX() {}
+  virtual ~nsUserIdleServiceX() {}
+};
+
+#endif  // nsUserIdleServiceX_h_
diff --git a/widget/cocoa/nsUserIdleServiceX.mm b/widget/cocoa/nsUserIdleServiceX.mm
new file mode 100644
index 0000000000..c3ae3f904f
--- /dev/null
+++ b/widget/cocoa/nsUserIdleServiceX.mm
@@ -0,0 +1,60 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsUserIdleServiceX.h"
+#include "nsObjCExceptions.h"
+#import <Foundation/Foundation.h>
+
+bool nsUserIdleServiceX::PollIdleTime(uint32_t* aIdleTime) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  kern_return_t rval;
+  mach_port_t masterPort;
+
+  rval = IOMasterPort(kIOMasterPortDefault, &masterPort);
+  if (rval != KERN_SUCCESS) return false;
+
+  io_iterator_t hidItr;
+  rval = IOServiceGetMatchingServices(
+      masterPort, IOServiceMatching("IOHIDSystem"), &hidItr);
+
+  if (rval != KERN_SUCCESS) return false;
+  NS_ASSERTION(hidItr, "Our iterator is null, but it ought not to be!");
+
+  io_registry_entry_t entry = IOIteratorNext(hidItr);
+  NS_ASSERTION(entry, "Our IO Registry Entry is null, but it shouldn't be!");
+
+  IOObjectRelease(hidItr);
+
+  NSMutableDictionary* hidProps;
+  rval = IORegistryEntryCreateCFProperties(
+      entry, (CFMutableDictionaryRef*)&hidProps, kCFAllocatorDefault, 0);
+  if (rval != KERN_SUCCESS) return false;
+  NS_ASSERTION(hidProps, "HIDProperties is null, but no error was returned.");
+  [hidProps autorelease];
+
+  id idleObj = [hidProps objectForKey:@"HIDIdleTime"];
+  NS_ASSERTION([idleObj isKindOfClass:[NSData class]] ||
+                   [idleObj isKindOfClass:[NSNumber class]],
+               "What we got for the idle object is not what we expect!");
+
+  uint64_t time;
+  if ([idleObj isKindOfClass:[NSData class]])
+    [idleObj getBytes:&time length:sizeof(time)];
+  else
+    time = [idleObj unsignedLongLongValue];
+
+  IOObjectRelease(entry);
+
+  // convert to ms from ns
+  time /= 1000000;
+  if (time > UINT32_MAX)  // Overflow will occur
+    return false;
+
+  *aIdleTime = static_cast<uint32_t>(time);
+
+  return true;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(false);
+}
diff --git a/widget/cocoa/nsWidgetFactory.h b/widget/cocoa/nsWidgetFactory.h
new file mode 100644
index 0000000000..ce3ca756db
--- /dev/null
+++ b/widget/cocoa/nsWidgetFactory.h
@@ -0,0 +1,44 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file contains forward declarations for classes defined in static
+// components. The appropriate headers for those types cannot be included in
+// the generated static component code directly.
+
+#include "nsID.h"
+
+namespace mozilla {
+class OSXNotificationCenter;
+}  // namespace mozilla
+
+namespace mozilla::widget {
+class ScreenManager;
+}
+
+class nsClipboardHelper;
+class nsColorPicker;
+class nsDeviceContextSpecX;
+class nsDragService;
+class nsFilePicker;
+class nsHTMLFormatConverter;
+class nsMacDockSupport;
+class nsMacFinderProgress;
+class nsMacSharingService;
+class nsMacUserActivityUpdater;
+class nsMacWebAppUtils;
+class nsPrintDialogServiceX;
+class nsPrintSettingsServiceX;
+class nsPrinterListCUPS;
+class nsSound;
+class nsStandaloneNativeMenu;
+class nsSystemStatusBarCocoa;
+class nsTouchBarUpdater;
+class nsTransferable;
+class nsUserIdleServiceX;
+
+nsresult nsAppShellConstructor(const nsIID&, void**);
+
+void nsWidgetCocoaModuleCtor();
+void nsWidgetCocoaModuleDtor();
diff --git a/widget/cocoa/nsWidgetFactory.mm b/widget/cocoa/nsWidgetFactory.mm
new file mode 100644
index 0000000000..3126b8c225
--- /dev/null
+++ b/widget/cocoa/nsWidgetFactory.mm
@@ -0,0 +1,124 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.h"
+#include "mozilla/Components.h"
+#include "mozilla/ModuleUtils.h"
+#include "mozilla/WidgetUtils.h"
+
+#include "nsWidgetsCID.h"
+
+#include "nsChildView.h"
+#include "nsAppShell.h"
+#include "nsAppShellSingleton.h"
+#include "nsFilePicker.h"
+#include "nsColorPicker.h"
+
+#include "nsClipboard.h"
+#include "nsClipboardHelper.h"
+#include "HeadlessClipboard.h"
+#include "gfxPlatform.h"
+#include "nsTransferable.h"
+#include "nsHTMLFormatConverter.h"
+#include "nsDragService.h"
+#include "nsToolkit.h"
+
+#include "nsLookAndFeel.h"
+
+#include "nsSound.h"
+#include "nsUserIdleServiceX.h"
+#include "NativeKeyBindings.h"
+#include "OSXNotificationCenter.h"
+
+#include "nsDeviceContextSpecX.h"
+#include "nsPrinterListCUPS.h"
+#include "nsPrintSettingsServiceX.h"
+#include "nsPrintDialogX.h"
+#include "nsToolkitCompsCID.h"
+
+#include "mozilla/widget/ScreenManager.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+NS_IMPL_COMPONENT_FACTORY(nsIClipboard) {
+  nsCOMPtr<nsIClipboard> inst;
+  if (gfxPlatform::IsHeadless()) {
+    inst = new HeadlessClipboard();
+  } else {
+    inst = new nsClipboard();
+  }
+
+  return inst.forget();
+}
+
+#define MAKE_GENERIC_CTOR(class_, iface_)    \
+  NS_IMPL_COMPONENT_FACTORY(class_) {        \
+    RefPtr inst = new class_();              \
+    return inst.forget().downcast<iface_>(); \
+  }
+
+#define MAKE_GENERIC_CTOR_INIT(class_, iface_, init_) \
+  NS_IMPL_COMPONENT_FACTORY(class_) {                 \
+    RefPtr inst = new class_();                       \
+    if (NS_SUCCEEDED(inst->init_())) {                \
+      return inst.forget().downcast<iface_>();        \
+    }                                                 \
+    return nullptr;                                   \
+  }
+
+#define MAKE_GENERIC_SINGLETON_CTOR(iface_, func_) \
+  NS_IMPL_COMPONENT_FACTORY(iface_) { return func_(); }
+
+MAKE_GENERIC_CTOR(nsFilePicker, nsIFilePicker)
+MAKE_GENERIC_CTOR(nsColorPicker, nsIColorPicker)
+MAKE_GENERIC_CTOR(nsSound, nsISound)
+MAKE_GENERIC_CTOR(nsTransferable, nsITransferable)
+MAKE_GENERIC_CTOR(nsHTMLFormatConverter, nsIFormatConverter)
+MAKE_GENERIC_CTOR(nsClipboardHelper, nsIClipboardHelper)
+MAKE_GENERIC_CTOR(nsDragService, nsIDragService)
+MAKE_GENERIC_CTOR(nsDeviceContextSpecX, nsIDeviceContextSpec)
+MAKE_GENERIC_CTOR(nsPrinterListCUPS, nsIPrinterList)
+MAKE_GENERIC_CTOR_INIT(nsPrintSettingsServiceX, nsIPrintSettingsService, Init)
+MAKE_GENERIC_CTOR_INIT(nsPrintDialogServiceX, nsIPrintDialogService, Init)
+MAKE_GENERIC_SINGLETON_CTOR(nsUserIdleServiceX, nsUserIdleServiceX::GetInstance)
+MAKE_GENERIC_SINGLETON_CTOR(ScreenManager, ScreenManager::GetAddRefedSingleton)
+MAKE_GENERIC_CTOR_INIT(OSXNotificationCenter, nsIAlertsService, Init)
+
+#include "nsMacDockSupport.h"
+MAKE_GENERIC_CTOR(nsMacDockSupport, nsIMacDockSupport)
+
+#include "nsMacFinderProgress.h"
+MAKE_GENERIC_CTOR(nsMacFinderProgress, nsIMacFinderProgress)
+
+#include "nsMacSharingService.h"
+MAKE_GENERIC_CTOR(nsMacSharingService, nsIMacSharingService)
+
+#include "nsMacUserActivityUpdater.h"
+MAKE_GENERIC_CTOR(nsMacUserActivityUpdater, nsIMacUserActivityUpdater)
+
+#include "nsMacWebAppUtils.h"
+MAKE_GENERIC_CTOR(nsMacWebAppUtils, nsIMacWebAppUtils)
+
+#include "nsStandaloneNativeMenu.h"
+MAKE_GENERIC_CTOR(nsStandaloneNativeMenu, nsIStandaloneNativeMenu)
+
+#include "nsSystemStatusBarCocoa.h"
+MAKE_GENERIC_CTOR(nsSystemStatusBarCocoa, nsISystemStatusBar)
+
+#include "nsTouchBarUpdater.h"
+MAKE_GENERIC_CTOR(nsTouchBarUpdater, nsITouchBarUpdater)
+
+void nsWidgetCocoaModuleCtor() { nsAppShellInit(); }
+
+void nsWidgetCocoaModuleDtor() {
+  // Shutdown all XP level widget classes.
+  WidgetUtils::Shutdown();
+
+  NativeKeyBindings::Shutdown();
+  nsLookAndFeel::Shutdown();
+  nsToolkit::Shutdown();
+  nsAppShellShutdown();
+}
diff --git a/widget/cocoa/nsWindowMap.h b/widget/cocoa/nsWindowMap.h
new file mode 100644
index 0000000000..ad742bd0d1
--- /dev/null
+++ b/widget/cocoa/nsWindowMap.h
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsWindowMap_h_
+#define nsWindowMap_h_
+
+#import <Cocoa/Cocoa.h>
+
+//  WindowDataMap
+//
+//  In both mozilla and embedding apps, we need to have a place to put
+//  per-top-level-window logic and data, to handle such things as IME
+//  commit when the window gains/loses focus. We can't use a window
+//  delegate, because an embeddor probably already has one. Nor can we
+//  subclass NSWindow, again because we can't impose that burden on the
+//  embeddor.
+//
+//  So we have a global map of NSWindow -> TopLevelWindowData, and set
+//  up TopLevelWindowData as a notification observer etc.
+
+@interface WindowDataMap : NSObject {
+ @private
+  NSMutableDictionary*
+      mWindowMap;  // dict of TopLevelWindowData keyed by address of NSWindow
+}
+
++ (WindowDataMap*)sharedWindowDataMap;
+
+- (void)ensureDataForWindow:(NSWindow*)inWindow;
+- (id)dataForWindow:(NSWindow*)inWindow;
+
+// set data for a given window. inData is retained (and any previously set data
+// is released).
+- (void)setData:(id)inData forWindow:(NSWindow*)inWindow;
+
+// remove the data for the given window. the data is released.
+- (void)removeDataForWindow:(NSWindow*)inWindow;
+
+@end
+
+@class ChildView;
+
+//  TopLevelWindowData
+//
+//  Class to hold per-window data, and handle window state changes.
+
+@interface TopLevelWindowData : NSObject {
+ @private
+}
+
+  - (id)initWithWindow:(NSWindow*)inWindow;
+  + (void)activateInWindow:(NSWindow*)aWindow;
+  + (void)deactivateInWindow:(NSWindow*)aWindow;
+  + (void)activateInWindowViews:(NSWindow*)aWindow;
+  + (void)deactivateInWindowViews:(NSWindow*)aWindow;
+
+  @end
+
+#endif  // nsWindowMap_h_
diff --git a/widget/cocoa/nsWindowMap.mm b/widget/cocoa/nsWindowMap.mm
new file mode 100644
index 0000000000..d93f89cb58
--- /dev/null
+++ b/widget/cocoa/nsWindowMap.mm
@@ -0,0 +1,291 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsWindowMap.h"
+#include "nsObjCExceptions.h"
+#include "nsChildView.h"
+#include "nsCocoaWindow.h"
+
+@interface WindowDataMap (Private)
+
+- (NSString*)keyForWindow:(NSWindow*)inWindow;
+
+@end
+
+@interface TopLevelWindowData (Private)
+
+- (void)windowResignedKey:(NSNotification*)inNotification;
+- (void)windowBecameKey:(NSNotification*)inNotification;
+- (void)windowWillClose:(NSNotification*)inNotification;
+
+@end
+
+#pragma mark -
+
+@implementation WindowDataMap
+
++ (WindowDataMap*)sharedWindowDataMap {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  static WindowDataMap* sWindowMap = nil;
+  if (!sWindowMap) sWindowMap = [[WindowDataMap alloc] init];
+
+  return sWindowMap;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (id)init {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if ((self = [super init])) {
+    mWindowMap = [[NSMutableDictionary alloc] initWithCapacity:10];
+  }
+  return self;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (void)dealloc {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [mWindowMap release];
+  [super dealloc];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)ensureDataForWindow:(NSWindow*)inWindow {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  if (!inWindow || [self dataForWindow:inWindow]) return;
+
+  TopLevelWindowData* windowData =
+      [[TopLevelWindowData alloc] initWithWindow:inWindow];
+  [self setData:windowData forWindow:inWindow];  // takes ownership
+  [windowData release];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (id)dataForWindow:(NSWindow*)inWindow {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return [mWindowMap objectForKey:[self keyForWindow:inWindow]];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (void)setData:(id)inData forWindow:(NSWindow*)inWindow {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [mWindowMap setObject:inData forKey:[self keyForWindow:inWindow]];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (void)removeDataForWindow:(NSWindow*)inWindow {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [mWindowMap removeObjectForKey:[self keyForWindow:inWindow]];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+- (NSString*)keyForWindow:(NSWindow*)inWindow {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  return [NSString stringWithFormat:@"%p", inWindow];
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+@end
+
+//  TopLevelWindowData
+//
+//  This class holds data about top-level windows. We can't use a window
+//  delegate, because an embedder may already have one.
+
+@implementation TopLevelWindowData
+
+- (id)initWithWindow:(NSWindow*)inWindow {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  if ((self = [super init])) {
+    [[NSNotificationCenter defaultCenter]
+        addObserver:self
+           selector:@selector(windowBecameKey:)
+               name:NSWindowDidBecomeKeyNotification
+             object:inWindow];
+
+    [[NSNotificationCenter defaultCenter]
+        addObserver:self
+           selector:@selector(windowResignedKey:)
+               name:NSWindowDidResignKeyNotification
+             object:inWindow];
+
+    [[NSNotificationCenter defaultCenter]
+        addObserver:self
+           selector:@selector(windowBecameMain:)
+               name:NSWindowDidBecomeMainNotification
+             object:inWindow];
+
+    [[NSNotificationCenter defaultCenter]
+        addObserver:self
+           selector:@selector(windowResignedMain:)
+               name:NSWindowDidResignMainNotification
+             object:inWindow];
+
+    [[NSNotificationCenter defaultCenter]
+        addObserver:self
+           selector:@selector(windowWillClose:)
+               name:NSWindowWillCloseNotification
+             object:inWindow];
+  }
+  return self;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(nil);
+}
+
+- (void)dealloc {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+  [super dealloc];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// As best I can tell, if the notification's object has a corresponding
+// top-level widget (an nsCocoaWindow object), it has a delegate (set in
+// nsCocoaWindow::StandardCreate()) of class WindowDelegate, and otherwise
+// not (Camino didn't use top-level widgets (nsCocoaWindow objects) --
+// only child widgets (nsChildView objects)).  (The notification is sent
+// to windowBecameKey: or windowBecameMain: below.)
+//
+// For use with clients that (like Firefox) do use top-level widgets (and
+// have NSWindow delegates of class WindowDelegate).
++ (void)activateInWindow:(NSWindow*)aWindow {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  WindowDelegate* delegate = (WindowDelegate*)[aWindow delegate];
+  if (!delegate || ![delegate isKindOfClass:[WindowDelegate class]]) return;
+
+  if ([delegate toplevelActiveState]) return;
+  [delegate sendToplevelActivateEvents];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// See comments above activateInWindow:
+//
+// If we're using top-level widgets (nsCocoaWindow objects), we send them
+// NS_DEACTIVATE events (which propagate to child widgets (nsChildView
+// objects) via nsWebShellWindow::HandleEvent()).
+//
+// For use with clients that (like Firefox) do use top-level widgets (and
+// have NSWindow delegates of class WindowDelegate).
++ (void)deactivateInWindow:(NSWindow*)aWindow {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  WindowDelegate* delegate = (WindowDelegate*)[aWindow delegate];
+  if (!delegate || ![delegate isKindOfClass:[WindowDelegate class]]) return;
+
+  if (![delegate toplevelActiveState]) return;
+  [delegate sendToplevelDeactivateEvents];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// For use with clients that (like Camino) don't use top-level widgets (and
+// don't have NSWindow delegates of class WindowDelegate).
++ (void)activateInWindowViews:(NSWindow*)aWindow {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  id firstResponder = [aWindow firstResponder];
+  if ([firstResponder isKindOfClass:[ChildView class]])
+    [firstResponder viewsWindowDidBecomeKey];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// For use with clients that (like Camino) don't use top-level widgets (and
+// don't have NSWindow delegates of class WindowDelegate).
++ (void)deactivateInWindowViews:(NSWindow*)aWindow {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  id firstResponder = [aWindow firstResponder];
+  if ([firstResponder isKindOfClass:[ChildView class]])
+    [firstResponder viewsWindowDidResignKey];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+// We make certain exceptions for top-level windows in non-embedders (see
+// comment above windowBecameMain below).  And we need (elsewhere) to guard
+// against sending duplicate events.  But in general the NS_ACTIVATE event
+// should be sent when a native window becomes key, and the NS_DEACTIVATE
+// event should be sent when it resignes key.
+- (void)windowBecameKey:(NSNotification*)inNotification {
+  NSWindow* window = (NSWindow*)[inNotification object];
+
+  id delegate = [window delegate];
+  if (!delegate || ![delegate isKindOfClass:[WindowDelegate class]]) {
+    [TopLevelWindowData activateInWindowViews:window];
+  } else if ([window isSheet] || [NSApp modalWindow]) {
+    [TopLevelWindowData activateInWindow:window];
+  }
+}
+
+- (void)windowResignedKey:(NSNotification*)inNotification {
+  NSWindow* window = (NSWindow*)[inNotification object];
+
+  id delegate = [window delegate];
+  if (!delegate || ![delegate isKindOfClass:[WindowDelegate class]]) {
+    [TopLevelWindowData deactivateInWindowViews:window];
+  } else if ([window isSheet] || [NSApp modalWindow]) {
+    [TopLevelWindowData deactivateInWindow:window];
+  }
+}
+
+// The appearance of a top-level window depends on its main state (not its key
+// state).  So (for non-embedders) we need to ensure that a top-level window
+// is main when an NS_ACTIVATE event is sent to Gecko for it.
+- (void)windowBecameMain:(NSNotification*)inNotification {
+  NSWindow* window = (NSWindow*)[inNotification object];
+
+  id delegate = [window delegate];
+  // Don't send events to a top-level window that has a sheet/modal-window open
+  // above it -- as far as Gecko is concerned, it's inactive, and stays so until
+  // the sheet/modal-window closes.
+  if (delegate && [delegate isKindOfClass:[WindowDelegate class]] &&
+      ![window attachedSheet] && ![NSApp modalWindow])
+    [TopLevelWindowData activateInWindow:window];
+}
+
+- (void)windowResignedMain:(NSNotification*)inNotification {
+  NSWindow* window = (NSWindow*)[inNotification object];
+
+  id delegate = [window delegate];
+  if (delegate && [delegate isKindOfClass:[WindowDelegate class]] &&
+      ![window attachedSheet] && ![NSApp modalWindow])
+    [TopLevelWindowData deactivateInWindow:window];
+}
+
+- (void)windowWillClose:(NSNotification*)inNotification {
+  NS_OBJC_BEGIN_TRY_IGNORE_BLOCK;
+
+  // postpone our destruction
+  [[self retain] autorelease];
+
+  // remove ourselves from the window map (which owns us)
+  [[WindowDataMap sharedWindowDataMap]
+      removeDataForWindow:[inNotification object]];
+
+  NS_OBJC_END_TRY_IGNORE_BLOCK;
+}
+
+@end
diff --git a/widget/cocoa/resources/MainMenu.nib/classes.nib b/widget/cocoa/resources/MainMenu.nib/classes.nib
new file mode 100644
index 0000000000..b9b4b09f6b
--- /dev/null
+++ b/widget/cocoa/resources/MainMenu.nib/classes.nib
@@ -0,0 +1,4 @@
+{
+    IBClasses = ({CLASS = FirstResponder; LANGUAGE = ObjC; SUPERCLASS = NSObject; }); 
+    IBVersion = 1; 
+}
\ No newline at end of file
diff --git a/widget/cocoa/resources/MainMenu.nib/info.nib b/widget/cocoa/resources/MainMenu.nib/info.nib
new file mode 100644
index 0000000000..bcf3ace841
--- /dev/null
+++ b/widget/cocoa/resources/MainMenu.nib/info.nib
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IBDocumentLocation</key>
+	<string>159 127 356 240 0 0 1920 1178 </string>
+	<key>IBEditorPositions</key>
+	<dict>
+		<key>29</key>
+		<string>413 971 130 44 0 0 1920 1178 </string>
+	</dict>
+	<key>IBFramework Version</key>
+	<string>443.0</string>
+	<key>IBOpenObjects</key>
+	<array>
+		<integer>29</integer>
+	</array>
+	<key>IBSystem Version</key>
+	<string>8F46</string>
+</dict>
+</plist>
diff --git a/widget/cocoa/resources/MainMenu.nib/keyedobjects.nib b/widget/cocoa/resources/MainMenu.nib/keyedobjects.nib
new file mode 100644
index 0000000000..16b3f7e523
--- /dev/null
+++ b/widget/cocoa/resources/MainMenu.nib/keyedobjects.nib
diff --git a/widget/components.conf b/widget/components.conf
new file mode 100644
index 0000000000..ecf1cd5009
--- /dev/null
+++ b/widget/components.conf
@@ -0,0 +1,83 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Classes = [
+    {
+        'js_name': 'clipboard',
+        'cid': '{8b5314ba-db01-11d2-96ce-0060b0fb9956}',
+        'contract_ids': ['@mozilla.org/widget/clipboard;1'],
+        'constructor': 'nsClipboardSelector',
+        'headers': ['/widget/nsContentProcessWidgetFactory.h'],
+        'interfaces': ['nsIClipboard'],
+        'overridable': True,
+    },
+    {
+        'cid': '{c0ed2a75-96f8-4166-91d4-2fe8774448dc}',
+        'type': 'nsClipboardProxy',
+        'headers': ['/widget/nsClipboardProxy.h'],
+        'contract_ids': ['@mozilla.org/widget/content/clipboard;1'],
+        'processes': ProcessSelector.CONTENT_PROCESS_ONLY,
+    },
+
+    {
+        'cid': '{0f872c8c-3ee6-46bd-92a2-69652c6b474e}',
+        'contract_ids': ['@mozilla.org/colorpicker;1'],
+        'constructor': 'nsColorPickerSelector',
+        'headers': ['/widget/nsContentProcessWidgetFactory.h'],
+    },
+    {
+        'cid': '{11a77259-9d16-4386-8ac8-94338ee22f78}',
+        'type': 'nsColorPickerProxy',
+        'headers': ['/widget/nsColorPickerProxy.h'],
+        'contract_ids': ['@mozilla.org/content/colorpicker;1'],
+        'processes': ProcessSelector.CONTENT_PROCESS_ONLY,
+    },
+
+    {
+        'cid': '{8b5314bb-db01-11d2-96ce-0060b0fb9956}',
+        'contract_ids': ['@mozilla.org/widget/dragservice;1'],
+        'constructor': 'nsDragServiceSelector',
+        'headers': ['/widget/nsContentProcessWidgetFactory.h'],
+    },
+    {
+        'cid': '{28be18ae-73ee-494f-8c6d-5d14b7c998c7}',
+        'type': 'nsDragServiceProxy',
+        'headers': ['/widget/nsDragServiceProxy.h'],
+        'contract_ids': ['@mozilla.org/widget/content/dragservice;1'],
+        'processes': ProcessSelector.CONTENT_PROCESS_ONLY,
+    },
+
+    {
+        'cid': '{bd57cee8-1dd1-11b2-9fe7-95cf4709aea3}',
+        'contract_ids': ['@mozilla.org/filepicker;1'],
+        'constructor': 'nsFilePickerSelector',
+        'headers': ['/widget/nsContentProcessWidgetFactory.h'],
+    },
+    {
+        'cid': '{40fd47f2-463a-4e4a-a33f-27eb148bfee4}',
+        'type': 'nsFilePickerProxy',
+        'headers': ['/widget/nsFilePickerProxy.h'],
+        'contract_ids': ['@mozilla.org/content/filepicker;1'],
+        'processes': ProcessSelector.CONTENT_PROCESS_ONLY,
+    },
+
+    {
+        'cid': '{c401eb80-f9ea-11d3-bb6f-e732b73ebe7c}',
+        'contract_ids': ['@mozilla.org/gfx/screenmanager;1'],
+        'singleton': True,
+        'constructor': 'nsScreenManagerSelector',
+        'headers': ['/widget/nsContentProcessWidgetFactory.h'],
+    },
+    {
+        'cid': '{b2cdd51c-4277-417b-a931-08306c7814c3}',
+        'type': 'mozilla::widget::ScreenManager',
+        'constructor': 'mozilla::widget::ScreenManager::GetAddRefedSingleton',
+        'headers': ['mozilla/widget/ScreenManager.h'],
+        'contract_ids': ['@mozilla.org/gfx/content/screenmanager;1'],
+        'singleton': True,
+        'processes': ProcessSelector.CONTENT_PROCESS_ONLY,
+    },
+]
diff --git a/widget/crashtests/1128214.html b/widget/crashtests/1128214.html
new file mode 100644
index 0000000000..749871c9e6
--- /dev/null
+++ b/widget/crashtests/1128214.html
@@ -0,0 +1,19 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+  <title>Testcase for bug 1128214</title>
+  <style type="text/css">
+    html,body {
+        color:black;
+        background-color:white;
+        font-size:16px;
+        padding:10px;
+        margin:0;
+    }
+  </style>
+</head>
+<body>
+<div style="-moz-appearance:-moz-window-button-close; background-color: #ffd800; width:20px; height:20px;"></div>
+</body>
+</html>
diff --git a/widget/crashtests/303901-1.html b/widget/crashtests/303901-1.html
new file mode 100644
index 0000000000..51511ba182
--- /dev/null
+++ b/widget/crashtests/303901-1.html
@@ -0,0 +1,29 @@
+<HEAD>
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+ MARGINWIDTH=$ SRC=& ADDRESS=^ onLoad=�������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������.gif SRC=ffff ADDRESS=? FRAMEBORDER=0xfffffff STYLE=QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ.rdf MARGINHEIGHT=? MARGINHEIGHT=89000 NAME=808080 WIDTH=-1 SCROLLING=chrome:�������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� >
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+<HEAD STYLE=http: onLoad=.swf STYLE=http:>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> onLoad=: onLoad=chrome: STYLE=89000 STYLE=http:yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy STYLE=? STYLE=ffff onLoad=90928345 onLoad=https:������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ STYLE=file:��������������������������������������������������������������������������������������������������������������������������������������������������� STYLE=\ onLoad=����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������.xul onLoad=about:3333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333333 onLoad=.swf STYLE=? onLoad=chrome:GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG STYLE=��������������������������������������������������������������������������������������������������������������������������������������������������������������������.ico STYLE=& >
+<SCRIPT LANGUAGE=% onLoad=808080 STYLE=������������������������������������������������������������.xbm LANGUAGE=file:666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666666 onLoad=about: onLoad=��������������������������������������������������������������������������������������������������������������������������.xpi STYLE=ssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss.ico onLoad=$ onLoad=�����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������.ico LANGUAGE=% onLoad=.xul onLoad=0xfffffff LANGUAGE=808080 onLoad=.ico STYLE=0 STYLE=%s%n%s%n%s%n%s%n%s%n%s%n STYLE=ffff STYLE=* LANGUAGE=* LANGUAGE=.gif >
+<OVERLAY X=hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh.rdf WIDTH=0xfffffff UNITS=0 Y=74326794236234 WIDTH=���������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������.png STYLE=about:TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT IMAGEMAP=^ WIDTH=ffff onLoad=A X=-1 IMAGEMAP=0xfffffff SRC=https:oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo SRC=7897 HEIGHT=�����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������.xpi HEIGHT=0xfffffff UNITS=* WIDTH=file:������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ Y=fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff.xpi IMAGEMAP=�������������������������������������������������������������������������������������������������������������������.dtd WIDTH=% >
+<B STYLE=^ STYLE=? STYLE=74326794236234 onLoad=https:�������������������������������� onLoad=http:������������������������������������������������������������������������������������������������������������������������������������ STYLE=& onLoad=7897 onLoad=
+ onLoad=808080 STYLE=https:QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ onLoad=74326794236234 onLoad=%s%n%s%n%s%n%s%n%s%n%s%n STYLE=7897 onLoad=: onLoad=90928345 onLoad=ffff onLoad=0xfffffff onLoad=%n%n%n%n%n%n%n%n%n%n%n%n STYLE=^ onLoad=$ >
diff --git a/widget/crashtests/303901-2.html b/widget/crashtests/303901-2.html
new file mode 100644
index 0000000000..00a70945d5
--- /dev/null
+++ b/widget/crashtests/303901-2.html
@@ -0,0 +1,20 @@
+<!DOCTYPE HTML>
+<html><head>
+    <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
+    <title>Testcase for bug </title>
+    <style type="text/css">
+
+        html,body {
+            color:black; background-color:white; font-size:16px; padding:0; margin:0;
+        }
+	
+
+    </style>
+</head>
+<body>
+
+<div style="overflow:scroll; height:200000px;"></div>
+
+
+</body>
+</html>
diff --git a/widget/crashtests/380359-1.xhtml b/widget/crashtests/380359-1.xhtml
new file mode 100644
index 0000000000..00b60506a1
--- /dev/null
+++ b/widget/crashtests/380359-1.xhtml
@@ -0,0 +1,8 @@
+<html xmlns="http://www.w3.org/1999/xhtml"
+      xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+<body>
+
+<xul:hbox style="display: block; position: fixed; -moz-appearance: checkbox;" />
+
+</body>
+</html>
diff --git a/widget/crashtests/crashtests.list b/widget/crashtests/crashtests.list
new file mode 100644
index 0000000000..957f3f005c
--- /dev/null
+++ b/widget/crashtests/crashtests.list
@@ -0,0 +1,4 @@
+load 303901-1.html
+load 303901-2.html
+load 380359-1.xhtml
+load 1128214.html
diff --git a/widget/generic/PCompositorWidget.ipdl b/widget/generic/PCompositorWidget.ipdl
new file mode 100644
index 0000000000..faa7bcda5a
--- /dev/null
+++ b/widget/generic/PCompositorWidget.ipdl
@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=99: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PCompositorBridge;
+
+// This file is a stub, for platforms that do not yet support out-of-process
+// compositing or do not need specialized types to do so.
+
+namespace mozilla {
+namespace widget {
+
+[ManualDealloc, ChildImpl=virtual, ParentImpl=virtual]
+sync protocol PCompositorWidget
+{
+  manager PCompositorBridge;
+
+parent:
+  async __delete__();
+
+child:
+  async ObserveVsync();
+  async UnobserveVsync();
+};
+
+} // namespace widget
+} // namespace mozilla
diff --git a/widget/generic/PlatformWidgetTypes.ipdlh b/widget/generic/PlatformWidgetTypes.ipdlh
new file mode 100644
index 0000000000..c4b6d2ca4f
--- /dev/null
+++ b/widget/generic/PlatformWidgetTypes.ipdlh
@@ -0,0 +1,21 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=99: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This file is a stub, for platforms that do not yet support out-of-process
+// compositing or do not need specialized types to do so.
+
+include HeadlessWidgetTypes;
+
+namespace mozilla {
+namespace widget {
+
+union CompositorWidgetInitData
+{
+  HeadlessCompositorWidgetInitData;
+};
+
+} // namespace widget
+} // namespace mozilla
diff --git a/widget/gtk/AsyncDBus.cpp b/widget/gtk/AsyncDBus.cpp
new file mode 100644
index 0000000000..ca560aca96
--- /dev/null
+++ b/widget/gtk/AsyncDBus.cpp
@@ -0,0 +1,90 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AsyncDBus.h"
+#include "mozilla/UniquePtrExtensions.h"
+
+namespace mozilla::widget {
+
+static void CreateProxyCallback(GObject*, GAsyncResult* aResult,
+                                gpointer aUserData) {
+  RefPtr<DBusProxyPromise::Private> promise =
+      dont_AddRef(static_cast<DBusProxyPromise::Private*>(aUserData));
+  GUniquePtr<GError> error;
+  RefPtr<GDBusProxy> proxy = dont_AddRef(
+      g_dbus_proxy_new_for_bus_finish(aResult, getter_Transfers(error)));
+  if (proxy) {
+    promise->Resolve(std::move(proxy), __func__);
+  } else {
+    promise->Reject(std::move(error), __func__);
+  }
+}
+
+RefPtr<DBusProxyPromise> CreateDBusProxyForBus(
+    GBusType aBusType, GDBusProxyFlags aFlags,
+    GDBusInterfaceInfo* aInterfaceInfo, const char* aName,
+    const char* aObjectPath, const char* aInterfaceName,
+    GCancellable* aCancellable) {
+  auto promise = MakeRefPtr<DBusProxyPromise::Private>(__func__);
+  g_dbus_proxy_new_for_bus(aBusType, aFlags, aInterfaceInfo, aName, aObjectPath,
+                           aInterfaceName, aCancellable, CreateProxyCallback,
+                           do_AddRef(promise).take());
+  return promise.forget();
+}
+
+static void ProxyCallCallback(GObject* aSourceObject, GAsyncResult* aResult,
+                              gpointer aUserData) {
+  RefPtr<DBusCallPromise::Private> promise =
+      dont_AddRef(static_cast<DBusCallPromise::Private*>(aUserData));
+  GUniquePtr<GError> error;
+  RefPtr<GVariant> result = dont_AddRef(g_dbus_proxy_call_finish(
+      G_DBUS_PROXY(aSourceObject), aResult, getter_Transfers(error)));
+  if (result) {
+    promise->Resolve(std::move(result), __func__);
+  } else {
+    promise->Reject(std::move(error), __func__);
+  }
+}
+
+RefPtr<DBusCallPromise> DBusProxyCall(GDBusProxy* aProxy, const char* aMethod,
+                                      GVariant* aArgs, GDBusCallFlags aFlags,
+                                      gint aTimeout,
+                                      GCancellable* aCancellable) {
+  auto promise = MakeRefPtr<DBusCallPromise::Private>(__func__);
+  g_dbus_proxy_call(aProxy, aMethod, aArgs, aFlags, aTimeout, aCancellable,
+                    ProxyCallCallback, do_AddRef(promise).take());
+  return promise.forget();
+}
+
+static void ProxyCallWithUnixFDListCallback(GObject* aSourceObject,
+                                            GAsyncResult* aResult,
+                                            gpointer aUserData) {
+  RefPtr<DBusCallPromise::Private> promise =
+      dont_AddRef(static_cast<DBusCallPromise::Private*>(aUserData));
+  GUniquePtr<GError> error;
+  GUnixFDList** aFDList = nullptr;
+  RefPtr<GVariant> result =
+      dont_AddRef(g_dbus_proxy_call_with_unix_fd_list_finish(
+          G_DBUS_PROXY(aSourceObject), aFDList, aResult,
+          getter_Transfers(error)));
+  if (result) {
+    promise->Resolve(std::move(result), __func__);
+  } else {
+    promise->Reject(std::move(error), __func__);
+  }
+}
+
+RefPtr<DBusCallPromise> DBusProxyCallWithUnixFDList(
+    GDBusProxy* aProxy, const char* aMethod, GVariant* aArgs,
+    GDBusCallFlags aFlags, gint aTimeout, GUnixFDList* aFDList,
+    GCancellable* aCancellable) {
+  auto promise = MakeRefPtr<DBusCallPromise::Private>(__func__);
+  g_dbus_proxy_call_with_unix_fd_list(
+      aProxy, aMethod, aArgs, aFlags, aTimeout, aFDList, aCancellable,
+      ProxyCallWithUnixFDListCallback, do_AddRef(promise).take());
+  return promise.forget();
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/AsyncDBus.h b/widget/gtk/AsyncDBus.h
new file mode 100644
index 0000000000..b1ac9d9039
--- /dev/null
+++ b/widget/gtk/AsyncDBus.h
@@ -0,0 +1,38 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_AsyncDBus_h
+#define mozilla_widget_AsyncDBus_h
+
+#include "mozilla/GRefPtr.h"
+#include "mozilla/GUniquePtr.h"
+#include "mozilla/MozPromise.h"
+
+namespace mozilla::widget {
+
+using DBusProxyPromise = MozPromise<RefPtr<GDBusProxy>, GUniquePtr<GError>,
+                                    /* IsExclusive = */ true>;
+
+using DBusCallPromise = MozPromise<RefPtr<GVariant>, GUniquePtr<GError>,
+                                   /* IsExclusive = */ true>;
+
+RefPtr<DBusProxyPromise> CreateDBusProxyForBus(
+    GBusType aBusType, GDBusProxyFlags aFlags,
+    GDBusInterfaceInfo* aInterfaceInfo, const char* aName,
+    const char* aObjectPath, const char* aInterfaceName,
+    GCancellable* aCancellable = nullptr);
+
+RefPtr<DBusCallPromise> DBusProxyCall(GDBusProxy*, const char* aMethod,
+                                      GVariant* aArgs, GDBusCallFlags,
+                                      gint aTimeout = -1,
+                                      GCancellable* = nullptr);
+
+RefPtr<DBusCallPromise> DBusProxyCallWithUnixFDList(
+    GDBusProxy*, const char* aMethod, GVariant* aArgs, GDBusCallFlags,
+    gint aTimeout = -1, GUnixFDList* = nullptr, GCancellable* = nullptr);
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/gtk/AsyncGtkClipboardRequest.cpp b/widget/gtk/AsyncGtkClipboardRequest.cpp
new file mode 100644
index 0000000000..75801c698d
--- /dev/null
+++ b/widget/gtk/AsyncGtkClipboardRequest.cpp
@@ -0,0 +1,120 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=4 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AsyncGtkClipboardRequest.h"
+
+namespace mozilla {
+
+AsyncGtkClipboardRequest::AsyncGtkClipboardRequest(ClipboardDataType aDataType,
+                                                   int32_t aWhichClipboard,
+                                                   const char* aMimeType) {
+  GtkClipboard* clipboard =
+      gtk_clipboard_get(GetSelectionAtom(aWhichClipboard));
+  mRequest = MakeUnique<Request>(aDataType);
+
+  switch (aDataType) {
+    case ClipboardDataType::Data:
+      LOGCLIP("  getting DATA MIME %s\n", aMimeType);
+      gtk_clipboard_request_contents(clipboard,
+                                     gdk_atom_intern(aMimeType, FALSE),
+                                     OnDataReceived, mRequest.get());
+      break;
+    case ClipboardDataType::Text:
+      LOGCLIP("  getting TEXT\n");
+      gtk_clipboard_request_text(clipboard, OnTextReceived, mRequest.get());
+      break;
+    case ClipboardDataType::Targets:
+      LOGCLIP("  getting TARGETS\n");
+      gtk_clipboard_request_contents(clipboard,
+                                     gdk_atom_intern("TARGETS", FALSE),
+                                     OnDataReceived, mRequest.get());
+      break;
+  }
+}
+
+void AsyncGtkClipboardRequest::OnDataReceived(GtkClipboard* clipboard,
+                                              GtkSelectionData* selection_data,
+                                              gpointer data) {
+  int whichClipboard = GetGeckoClipboardType(clipboard);
+  LOGCLIP("OnDataReceived(%s) callback\n",
+          whichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                             : "clipboard");
+  static_cast<Request*>(data)->Complete(selection_data);
+}
+
+void AsyncGtkClipboardRequest::OnTextReceived(GtkClipboard* clipboard,
+                                              const gchar* text,
+                                              gpointer data) {
+  int whichClipboard = GetGeckoClipboardType(clipboard);
+  LOGCLIP("OnTextReceived(%s) callback\n",
+          whichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                             : "clipboard");
+  static_cast<Request*>(data)->Complete(text);
+}
+
+void AsyncGtkClipboardRequest::Request::Complete(const void* aData) {
+  LOGCLIP("Request::Complete(), aData = %p, timedOut = %d\n", aData, mTimedOut);
+
+  if (mTimedOut) {
+    delete this;
+    return;
+  }
+
+  mData.emplace();
+
+  gint dataLength = 0;
+  if (mDataType == ClipboardDataType::Targets ||
+      mDataType == ClipboardDataType::Data) {
+    dataLength = gtk_selection_data_get_length((GtkSelectionData*)aData);
+  } else {
+    dataLength = aData ? strlen((const char*)aData) : 0;
+  }
+
+  // Negative size means no data or data error.
+  if (dataLength <= 0) {
+    LOGCLIP("    zero dataLength, quit.\n");
+    return;
+  }
+
+  switch (mDataType) {
+    case ClipboardDataType::Targets: {
+      LOGCLIP("    getting %d bytes of clipboard targets.\n", dataLength);
+      gint n_targets = 0;
+      GdkAtom* targets = nullptr;
+      if (!gtk_selection_data_get_targets((GtkSelectionData*)aData, &targets,
+                                          &n_targets) ||
+          !n_targets) {
+        // We failed to get targets
+        return;
+      }
+      mData->SetTargets(
+          ClipboardTargets{GUniquePtr<GdkAtom>(targets), uint32_t(n_targets)});
+      break;
+    }
+    case ClipboardDataType::Text: {
+      LOGCLIP("    getting %d bytes of text.\n", dataLength);
+      mData->SetText(Span(static_cast<const char*>(aData), dataLength));
+      LOGCLIP("    done, mClipboardData = %p\n", mData->AsSpan().data());
+      break;
+    }
+    case ClipboardDataType::Data: {
+      LOGCLIP("    getting %d bytes of data.\n", dataLength);
+      mData->SetData(Span(gtk_selection_data_get_data((GtkSelectionData*)aData),
+                          dataLength));
+      LOGCLIP("    done, mClipboardData = %p\n", mData->AsSpan().data());
+      break;
+    }
+  }
+}
+
+AsyncGtkClipboardRequest::~AsyncGtkClipboardRequest() {
+  if (mRequest && mRequest->mData.isNothing()) {
+    mRequest->mTimedOut = true;
+    Unused << mRequest.release();
+  }
+}
+
+}  // namespace mozilla
diff --git a/widget/gtk/AsyncGtkClipboardRequest.h b/widget/gtk/AsyncGtkClipboardRequest.h
new file mode 100644
index 0000000000..1d72691560
--- /dev/null
+++ b/widget/gtk/AsyncGtkClipboardRequest.h
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_AsyncGtkClipboardRequest_h
+#define mozilla_AsyncGtkClipboardRequest_h
+
+#include "nsClipboard.h"
+
+namespace mozilla {
+
+// An asynchronous clipboard request that we wait for synchronously by
+// spinning the event loop.
+class MOZ_STACK_CLASS AsyncGtkClipboardRequest {
+  // Heap-allocated object that we give GTK as a callback.
+  struct Request {
+    explicit Request(ClipboardDataType aDataType) : mDataType(aDataType) {}
+
+    void Complete(const void*);
+
+    const ClipboardDataType mDataType;
+    Maybe<ClipboardData> mData;
+    bool mTimedOut = false;
+  };
+
+  UniquePtr<Request> mRequest;
+
+  static void OnDataReceived(GtkClipboard*, GtkSelectionData*, gpointer);
+  static void OnTextReceived(GtkClipboard*, const gchar*, gpointer);
+
+ public:
+  // Launch a request for a particular GTK clipboard. The current status of the
+  // request can be observed by calling HasCompleted() and TakeResult().
+  AsyncGtkClipboardRequest(ClipboardDataType, int32_t aWhichClipboard,
+                           const char* aMimeType = nullptr);
+
+  // Returns whether the request has been answered already.
+  bool HasCompleted() const { return mRequest->mData.isSome(); }
+
+  // Takes the result from the current request if completed, or a
+  // default-constructed data otherwise. The destructor will take care of
+  // flagging the request as timed out in that case.
+  ClipboardData TakeResult() {
+    if (!HasCompleted()) {
+      return {};
+    }
+    auto request = std::move(mRequest);
+    return request->mData.extract();
+  }
+
+  // If completed, frees the request if needed. Otherwise, marks it as a timed
+  // out request so that when it completes the Request object is properly
+  // freed.
+  ~AsyncGtkClipboardRequest();
+};
+
+};  // namespace mozilla
+
+#endif
diff --git a/widget/gtk/CompositorWidgetChild.cpp b/widget/gtk/CompositorWidgetChild.cpp
new file mode 100644
index 0000000000..b7908a43d4
--- /dev/null
+++ b/widget/gtk/CompositorWidgetChild.cpp
@@ -0,0 +1,51 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CompositorWidgetChild.h"
+#include "mozilla/Unused.h"
+#include "gfxPlatform.h"
+
+namespace mozilla {
+namespace widget {
+
+CompositorWidgetChild::CompositorWidgetChild(
+    RefPtr<CompositorVsyncDispatcher> aVsyncDispatcher,
+    RefPtr<CompositorWidgetVsyncObserver> aVsyncObserver,
+    const CompositorWidgetInitData&)
+    : mVsyncDispatcher(aVsyncDispatcher), mVsyncObserver(aVsyncObserver) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(!gfxPlatform::IsHeadless());
+}
+
+CompositorWidgetChild::~CompositorWidgetChild() = default;
+
+bool CompositorWidgetChild::Initialize() { return true; }
+
+mozilla::ipc::IPCResult CompositorWidgetChild::RecvObserveVsync() {
+  mVsyncDispatcher->SetCompositorVsyncObserver(mVsyncObserver);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult CompositorWidgetChild::RecvUnobserveVsync() {
+  mVsyncDispatcher->SetCompositorVsyncObserver(nullptr);
+  return IPC_OK();
+}
+
+void CompositorWidgetChild::NotifyClientSizeChanged(
+    const LayoutDeviceIntSize& aClientSize) {
+  Unused << SendNotifyClientSizeChanged(aClientSize);
+}
+
+void CompositorWidgetChild::DisableRendering() {
+  Unused << SendDisableRendering();
+}
+
+void CompositorWidgetChild::EnableRendering(const uintptr_t aXWindow,
+                                            const bool aShaped) {
+  Unused << SendEnableRendering(aXWindow, aShaped);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/gtk/CompositorWidgetChild.h b/widget/gtk/CompositorWidgetChild.h
new file mode 100644
index 0000000000..b1cad75da3
--- /dev/null
+++ b/widget/gtk/CompositorWidgetChild.h
@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_gtk_CompositorWidgetChild_h
+#define widget_gtk_CompositorWidgetChild_h
+
+#include "GtkCompositorWidget.h"
+#include "mozilla/widget/PCompositorWidgetChild.h"
+#include "mozilla/widget/CompositorWidgetVsyncObserver.h"
+
+namespace mozilla {
+namespace widget {
+
+class CompositorWidgetChild final : public PCompositorWidgetChild,
+                                    public PlatformCompositorWidgetDelegate {
+ public:
+  CompositorWidgetChild(RefPtr<CompositorVsyncDispatcher> aVsyncDispatcher,
+                        RefPtr<CompositorWidgetVsyncObserver> aVsyncObserver,
+                        const CompositorWidgetInitData&);
+  ~CompositorWidgetChild() override;
+
+  bool Initialize();
+
+  mozilla::ipc::IPCResult RecvObserveVsync() override;
+  mozilla::ipc::IPCResult RecvUnobserveVsync() override;
+
+  void NotifyClientSizeChanged(const LayoutDeviceIntSize& aClientSize) override;
+  void DisableRendering() override;
+  void EnableRendering(const uintptr_t aXWindow, const bool aShaped) override;
+
+ private:
+  RefPtr<CompositorVsyncDispatcher> mVsyncDispatcher;
+  RefPtr<CompositorWidgetVsyncObserver> mVsyncObserver;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_gtk_CompositorWidgetChild_h
diff --git a/widget/gtk/CompositorWidgetParent.cpp b/widget/gtk/CompositorWidgetParent.cpp
new file mode 100644
index 0000000000..998614622e
--- /dev/null
+++ b/widget/gtk/CompositorWidgetParent.cpp
@@ -0,0 +1,54 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CompositorWidgetParent.h"
+#include "mozilla/Unused.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "nsWindow.h"
+
+namespace mozilla::widget {
+
+CompositorWidgetParent::CompositorWidgetParent(
+    const CompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions)
+    : GtkCompositorWidget(aInitData.get_GtkCompositorWidgetInitData(), aOptions,
+                          nullptr) {
+  MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_GPU);
+}
+
+CompositorWidgetParent::~CompositorWidgetParent() = default;
+
+void CompositorWidgetParent::ObserveVsync(VsyncObserver* aObserver) {
+  if (aObserver) {
+    Unused << SendObserveVsync();
+  } else {
+    Unused << SendUnobserveVsync();
+  }
+  mVsyncObserver = aObserver;
+}
+
+RefPtr<VsyncObserver> CompositorWidgetParent::GetVsyncObserver() const {
+  MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_GPU);
+  return mVsyncObserver;
+}
+
+mozilla::ipc::IPCResult CompositorWidgetParent::RecvNotifyClientSizeChanged(
+    const LayoutDeviceIntSize& aClientSize) {
+  NotifyClientSizeChanged(aClientSize);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult CompositorWidgetParent::RecvDisableRendering() {
+  DisableRendering();
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult CompositorWidgetParent::RecvEnableRendering(
+    const uintptr_t& aXWindow, const bool& aShaped) {
+  EnableRendering(aXWindow, aShaped);
+  return IPC_OK();
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/CompositorWidgetParent.h b/widget/gtk/CompositorWidgetParent.h
new file mode 100644
index 0000000000..2bbc70af3e
--- /dev/null
+++ b/widget/gtk/CompositorWidgetParent.h
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_gtk_CompositorWidgetParent_h
+#define widget_gtk_CompositorWidgetParent_h
+
+#include "GtkCompositorWidget.h"
+#include "mozilla/VsyncDispatcher.h"
+#include "mozilla/widget/PCompositorWidgetParent.h"
+
+namespace mozilla {
+namespace widget {
+
+class CompositorWidgetParent final : public PCompositorWidgetParent,
+                                     public GtkCompositorWidget {
+ public:
+  explicit CompositorWidgetParent(const CompositorWidgetInitData& aInitData,
+                                  const layers::CompositorOptions& aOptions);
+  ~CompositorWidgetParent() override;
+
+  void ActorDestroy(ActorDestroyReason aWhy) override {}
+
+  void ObserveVsync(VsyncObserver* aObserver) override;
+  RefPtr<VsyncObserver> GetVsyncObserver() const override;
+
+  mozilla::ipc::IPCResult RecvNotifyClientSizeChanged(
+      const LayoutDeviceIntSize& aClientSize) override;
+
+  mozilla::ipc::IPCResult RecvDisableRendering() override;
+  mozilla::ipc::IPCResult RecvEnableRendering(const uintptr_t& aXWindow,
+                                              const bool& aShaped) override;
+
+ private:
+  RefPtr<VsyncObserver> mVsyncObserver;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_gtk_CompositorWidgetParent_h
diff --git a/widget/gtk/DMABufLibWrapper.cpp b/widget/gtk/DMABufLibWrapper.cpp
new file mode 100644
index 0000000000..3db0219f88
--- /dev/null
+++ b/widget/gtk/DMABufLibWrapper.cpp
@@ -0,0 +1,346 @@
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DMABufLibWrapper.h"
+#ifdef MOZ_WAYLAND
+#  include "nsWaylandDisplay.h"
+#endif
+#include "base/message_loop.h"  // for MessageLoop
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/StaticPrefs_media.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "WidgetUtilsGtk.h"
+#include "gfxConfig.h"
+#include "nsIGfxInfo.h"
+#include "mozilla/Components.h"
+#include "mozilla/ClearOnShutdown.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <dlfcn.h>
+#include <mutex>
+#include <unistd.h>
+#include "gbm.h"
+
+using namespace mozilla::gfx;
+
+namespace mozilla {
+namespace widget {
+
+bool sUseWebGLDmabufBackend = true;
+
+#define GBMLIB_NAME "libgbm.so.1"
+#define DRMLIB_NAME "libdrm.so.2"
+
+// Use static lock to protect dri operation as
+// gbm_dri.c is not thread safe.
+// https://gitlab.freedesktop.org/mesa/mesa/-/issues/4422
+mozilla::StaticMutex GbmLib::sDRILock MOZ_UNANNOTATED;
+
+bool GbmLib::sLoaded = false;
+void* GbmLib::sGbmLibHandle = nullptr;
+void* GbmLib::sXf86DrmLibHandle = nullptr;
+CreateDeviceFunc GbmLib::sCreateDevice;
+DestroyDeviceFunc GbmLib::sDestroyDevice;
+CreateFunc GbmLib::sCreate;
+CreateWithModifiersFunc GbmLib::sCreateWithModifiers;
+GetModifierFunc GbmLib::sGetModifier;
+GetStrideFunc GbmLib::sGetStride;
+GetFdFunc GbmLib::sGetFd;
+DestroyFunc GbmLib::sDestroy;
+MapFunc GbmLib::sMap;
+UnmapFunc GbmLib::sUnmap;
+GetPlaneCountFunc GbmLib::sGetPlaneCount;
+GetHandleForPlaneFunc GbmLib::sGetHandleForPlane;
+GetStrideForPlaneFunc GbmLib::sGetStrideForPlane;
+GetOffsetFunc GbmLib::sGetOffset;
+DeviceIsFormatSupportedFunc GbmLib::sDeviceIsFormatSupported;
+DrmPrimeHandleToFDFunc GbmLib::sDrmPrimeHandleToFD;
+CreateSurfaceFunc GbmLib::sCreateSurface;
+DestroySurfaceFunc GbmLib::sDestroySurface;
+
+bool GbmLib::IsLoaded() {
+  return sCreateDevice != nullptr && sDestroyDevice != nullptr &&
+         sCreate != nullptr && sCreateWithModifiers != nullptr &&
+         sGetModifier != nullptr && sGetStride != nullptr &&
+         sGetFd != nullptr && sDestroy != nullptr && sMap != nullptr &&
+         sUnmap != nullptr && sGetPlaneCount != nullptr &&
+         sGetHandleForPlane != nullptr && sGetStrideForPlane != nullptr &&
+         sGetOffset != nullptr && sDeviceIsFormatSupported != nullptr &&
+         sDrmPrimeHandleToFD != nullptr && sCreateSurface != nullptr &&
+         sDestroySurface != nullptr;
+}
+
+bool GbmLib::Load() {
+  static bool sTriedToLoad = false;
+  if (sTriedToLoad) {
+    return sLoaded;
+  }
+
+  sTriedToLoad = true;
+
+  MOZ_ASSERT(!sGbmLibHandle);
+  MOZ_ASSERT(!sLoaded);
+
+  LOGDMABUF(("Loading DMABuf system library %s ...\n", GBMLIB_NAME));
+
+  sGbmLibHandle = dlopen(GBMLIB_NAME, RTLD_LAZY | RTLD_LOCAL);
+  if (!sGbmLibHandle) {
+    LOGDMABUF(("Failed to load %s, dmabuf isn't available.\n", GBMLIB_NAME));
+    return false;
+  }
+
+  sCreateDevice = (CreateDeviceFunc)dlsym(sGbmLibHandle, "gbm_create_device");
+  sDestroyDevice =
+      (DestroyDeviceFunc)dlsym(sGbmLibHandle, "gbm_device_destroy");
+  sCreate = (CreateFunc)dlsym(sGbmLibHandle, "gbm_bo_create");
+  sCreateWithModifiers = (CreateWithModifiersFunc)dlsym(
+      sGbmLibHandle, "gbm_bo_create_with_modifiers");
+  sGetModifier = (GetModifierFunc)dlsym(sGbmLibHandle, "gbm_bo_get_modifier");
+  sGetStride = (GetStrideFunc)dlsym(sGbmLibHandle, "gbm_bo_get_stride");
+  sGetFd = (GetFdFunc)dlsym(sGbmLibHandle, "gbm_bo_get_fd");
+  sDestroy = (DestroyFunc)dlsym(sGbmLibHandle, "gbm_bo_destroy");
+  sMap = (MapFunc)dlsym(sGbmLibHandle, "gbm_bo_map");
+  sUnmap = (UnmapFunc)dlsym(sGbmLibHandle, "gbm_bo_unmap");
+  sGetPlaneCount =
+      (GetPlaneCountFunc)dlsym(sGbmLibHandle, "gbm_bo_get_plane_count");
+  sGetHandleForPlane = (GetHandleForPlaneFunc)dlsym(
+      sGbmLibHandle, "gbm_bo_get_handle_for_plane");
+  sGetStrideForPlane = (GetStrideForPlaneFunc)dlsym(
+      sGbmLibHandle, "gbm_bo_get_stride_for_plane");
+  sGetOffset = (GetOffsetFunc)dlsym(sGbmLibHandle, "gbm_bo_get_offset");
+  sDeviceIsFormatSupported = (DeviceIsFormatSupportedFunc)dlsym(
+      sGbmLibHandle, "gbm_device_is_format_supported");
+  sCreateSurface =
+      (CreateSurfaceFunc)dlsym(sGbmLibHandle, "gbm_surface_create");
+  sDestroySurface =
+      (DestroySurfaceFunc)dlsym(sGbmLibHandle, "gbm_surface_destroy");
+
+  sXf86DrmLibHandle = dlopen(DRMLIB_NAME, RTLD_LAZY | RTLD_LOCAL);
+  if (!sXf86DrmLibHandle) {
+    LOGDMABUF(("Failed to load %s, dmabuf isn't available.\n", DRMLIB_NAME));
+    return false;
+  }
+  sDrmPrimeHandleToFD =
+      (DrmPrimeHandleToFDFunc)dlsym(sXf86DrmLibHandle, "drmPrimeHandleToFD");
+  sLoaded = IsLoaded();
+  if (!sLoaded) {
+    LOGDMABUF(("Failed to load all symbols from %s\n", GBMLIB_NAME));
+  }
+  return sLoaded;
+}
+
+int DMABufDevice::GetDmabufFD(uint32_t aGEMHandle) {
+  int fd;
+  return GbmLib::DrmPrimeHandleToFD(mDRMFd, aGEMHandle, 0, &fd) < 0 ? -1 : fd;
+}
+
+gbm_device* DMABufDevice::GetGbmDevice() {
+  std::call_once(mFlagGbmDevice, [&] {
+    mGbmDevice = (mDRMFd != -1) ? GbmLib::CreateDevice(mDRMFd) : nullptr;
+  });
+  return mGbmDevice;
+}
+
+int DMABufDevice::OpenDRMFd() { return open(mDrmRenderNode.get(), O_RDWR); }
+
+bool DMABufDevice::IsEnabled(nsACString& aFailureId) {
+  if (mDRMFd == -1) {
+    aFailureId = mFailureId;
+  }
+  return mDRMFd != -1;
+}
+
+DMABufDevice::DMABufDevice()
+    : mXRGBFormat({true, false, GBM_FORMAT_XRGB8888, {}}),
+      mARGBFormat({true, true, GBM_FORMAT_ARGB8888, {}}) {
+  Configure();
+}
+
+DMABufDevice::~DMABufDevice() {
+  if (mGbmDevice) {
+    GbmLib::DestroyDevice(mGbmDevice);
+    mGbmDevice = nullptr;
+  }
+  if (mDRMFd != -1) {
+    close(mDRMFd);
+    mDRMFd = -1;
+  }
+}
+
+void DMABufDevice::Configure() {
+  LOGDMABUF(("DMABufDevice::Configure()"));
+
+  if (!GbmLib::IsAvailable()) {
+    LOGDMABUF(("GbmLib is not available!"));
+    mFailureId = "FEATURE_FAILURE_NO_LIBGBM";
+    return;
+  }
+
+  mDrmRenderNode = nsAutoCString(getenv("MOZ_DRM_DEVICE"));
+  if (mDrmRenderNode.IsEmpty()) {
+    mDrmRenderNode.Assign(gfx::gfxVars::DrmRenderDevice());
+  }
+  if (mDrmRenderNode.IsEmpty()) {
+    LOGDMABUF(("We're missing DRM render device!\n"));
+    mFailureId = "FEATURE_FAILURE_NO_DRM_DEVICE";
+    return;
+  }
+
+  LOGDMABUF(("Using DRM device %s", mDrmRenderNode.get()));
+  mDRMFd = open(mDrmRenderNode.get(), O_RDWR);
+  if (mDRMFd < 0) {
+    LOGDMABUF(("Failed to open drm render node %s error %s\n",
+               mDrmRenderNode.get(), strerror(errno)));
+    mFailureId = "FEATURE_FAILURE_NO_DRM_DEVICE";
+    return;
+  }
+
+#ifdef MOZ_WAYLAND
+  LoadFormatModifiers();
+#endif
+
+  LOGDMABUF(("DMABuf is enabled"));
+}
+
+#ifdef NIGHTLY_BUILD
+bool DMABufDevice::IsDMABufTexturesEnabled() {
+  return gfx::gfxVars::UseDMABuf() &&
+         StaticPrefs::widget_dmabuf_textures_enabled();
+}
+#else
+bool DMABufDevice::IsDMABufTexturesEnabled() { return false; }
+#endif
+bool DMABufDevice::IsDMABufWebGLEnabled() {
+  LOGDMABUF(
+      ("DMABufDevice::IsDMABufWebGLEnabled: UseDMABuf %d "
+       "sUseWebGLDmabufBackend %d "
+       "widget_dmabuf_webgl_enabled %d\n",
+       gfx::gfxVars::UseDMABuf(), sUseWebGLDmabufBackend,
+       StaticPrefs::widget_dmabuf_webgl_enabled()));
+  return gfx::gfxVars::UseDMABuf() && sUseWebGLDmabufBackend &&
+         StaticPrefs::widget_dmabuf_webgl_enabled();
+}
+
+#ifdef MOZ_WAYLAND
+void DMABufDevice::SetModifiersToGfxVars() {
+  gfxVars::SetDMABufModifiersXRGB(mXRGBFormat.mModifiers);
+  gfxVars::SetDMABufModifiersARGB(mARGBFormat.mModifiers);
+}
+
+void DMABufDevice::GetModifiersFromGfxVars() {
+  mXRGBFormat.mModifiers = gfxVars::DMABufModifiersXRGB().Clone();
+  mARGBFormat.mModifiers = gfxVars::DMABufModifiersARGB().Clone();
+}
+#endif
+
+void DMABufDevice::DisableDMABufWebGL() { sUseWebGLDmabufBackend = false; }
+
+GbmFormat* DMABufDevice::GetGbmFormat(bool aHasAlpha) {
+  GbmFormat* format = aHasAlpha ? &mARGBFormat : &mXRGBFormat;
+  return format->mIsSupported ? format : nullptr;
+}
+
+#ifdef MOZ_WAYLAND
+void DMABufDevice::AddFormatModifier(bool aHasAlpha, int aFormat,
+                                     uint32_t mModifierHi,
+                                     uint32_t mModifierLo) {
+  GbmFormat* format = aHasAlpha ? &mARGBFormat : &mXRGBFormat;
+  format->mIsSupported = true;
+  format->mHasAlpha = aHasAlpha;
+  format->mFormat = aFormat;
+  format->mModifiers.AppendElement(((uint64_t)mModifierHi << 32) | mModifierLo);
+}
+
+static void dmabuf_modifiers(void* data,
+                             struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf,
+                             uint32_t format, uint32_t modifier_hi,
+                             uint32_t modifier_lo) {
+  // skip modifiers marked as invalid
+  if (modifier_hi == (DRM_FORMAT_MOD_INVALID >> 32) &&
+      modifier_lo == (DRM_FORMAT_MOD_INVALID & 0xffffffff)) {
+    return;
+  }
+
+  auto* device = static_cast<DMABufDevice*>(data);
+  switch (format) {
+    case GBM_FORMAT_ARGB8888:
+      device->AddFormatModifier(true, format, modifier_hi, modifier_lo);
+      break;
+    case GBM_FORMAT_XRGB8888:
+      device->AddFormatModifier(false, format, modifier_hi, modifier_lo);
+      break;
+    default:
+      break;
+  }
+}
+
+static void dmabuf_format(void* data,
+                          struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf,
+                          uint32_t format) {
+  // XXX: deprecated
+}
+
+static const struct zwp_linux_dmabuf_v1_listener dmabuf_listener = {
+    dmabuf_format, dmabuf_modifiers};
+
+static void global_registry_handler(void* data, wl_registry* registry,
+                                    uint32_t id, const char* interface,
+                                    uint32_t version) {
+  if (strcmp(interface, "zwp_linux_dmabuf_v1") == 0 && version > 2) {
+    auto* dmabuf = WaylandRegistryBind<zwp_linux_dmabuf_v1>(
+        registry, id, &zwp_linux_dmabuf_v1_interface, 3);
+    LOGDMABUF(("zwp_linux_dmabuf_v1 is available."));
+    zwp_linux_dmabuf_v1_add_listener(dmabuf, &dmabuf_listener, data);
+  } else if (strcmp(interface, "wl_drm") == 0) {
+    LOGDMABUF(("wl_drm is available."));
+  }
+}
+
+static void global_registry_remover(void* data, wl_registry* registry,
+                                    uint32_t id) {}
+
+static const struct wl_registry_listener registry_listener = {
+    global_registry_handler, global_registry_remover};
+
+void DMABufDevice::LoadFormatModifiers() {
+  if (!GdkIsWaylandDisplay()) {
+    return;
+  }
+  if (XRE_IsParentProcess()) {
+    MOZ_ASSERT(NS_IsMainThread());
+    wl_display* display = WaylandDisplayGetWLDisplay();
+    wl_registry* registry = wl_display_get_registry(display);
+    wl_registry_add_listener(registry, &registry_listener, this);
+    wl_display_roundtrip(display);
+    wl_display_roundtrip(display);
+    wl_registry_destroy(registry);
+    SetModifiersToGfxVars();
+  } else {
+    GetModifiersFromGfxVars();
+  }
+}
+#endif
+
+DMABufDevice* GetDMABufDevice() {
+  static StaticAutoPtr<DMABufDevice> sDmaBufDevice;
+  static std::once_flag onceFlag;
+  std::call_once(onceFlag, [] {
+    sDmaBufDevice = new DMABufDevice();
+    if (NS_IsMainThread()) {
+      ClearOnShutdown(&sDmaBufDevice);
+    } else {
+      NS_DispatchToMainThread(NS_NewRunnableFunction(
+          "ClearDmaBufDevice", [] { ClearOnShutdown(&sDmaBufDevice); }));
+    }
+  });
+  return sDmaBufDevice.get();
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/gtk/DMABufLibWrapper.h b/widget/gtk/DMABufLibWrapper.h
new file mode 100644
index 0000000000..9723083ad8
--- /dev/null
+++ b/widget/gtk/DMABufLibWrapper.h
@@ -0,0 +1,231 @@
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __MOZ_DMABUF_LIB_WRAPPER_H__
+#define __MOZ_DMABUF_LIB_WRAPPER_H__
+
+#include "mozilla/widget/gbm.h"
+#include "mozilla/StaticMutex.h"
+#include <mutex>
+
+#ifdef MOZ_LOGGING
+#  include "mozilla/Logging.h"
+#  include "nsTArray.h"
+#  include "Units.h"
+extern mozilla::LazyLogModule gDmabufLog;
+#  define LOGDMABUF(args) MOZ_LOG(gDmabufLog, mozilla::LogLevel::Debug, args)
+#else
+#  define LOGDMABUF(args)
+#endif /* MOZ_LOGGING */
+
+#ifndef DRM_FORMAT_MOD_INVALID
+#  define DRM_FORMAT_MOD_INVALID ((1ULL << 56) - 1)
+#endif
+
+namespace mozilla {
+namespace widget {
+
+typedef struct gbm_device* (*CreateDeviceFunc)(int);
+typedef void (*DestroyDeviceFunc)(struct gbm_device*);
+typedef struct gbm_bo* (*CreateFunc)(struct gbm_device*, uint32_t, uint32_t,
+                                     uint32_t, uint32_t);
+typedef struct gbm_bo* (*CreateWithModifiersFunc)(struct gbm_device*, uint32_t,
+                                                  uint32_t, uint32_t,
+                                                  const uint64_t*,
+                                                  const unsigned int);
+typedef uint64_t (*GetModifierFunc)(struct gbm_bo*);
+typedef uint32_t (*GetStrideFunc)(struct gbm_bo*);
+typedef int (*GetFdFunc)(struct gbm_bo*);
+typedef void (*DestroyFunc)(struct gbm_bo*);
+typedef void* (*MapFunc)(struct gbm_bo*, uint32_t, uint32_t, uint32_t, uint32_t,
+                         uint32_t, uint32_t*, void**);
+typedef void (*UnmapFunc)(struct gbm_bo*, void*);
+typedef int (*GetPlaneCountFunc)(struct gbm_bo*);
+typedef union gbm_bo_handle (*GetHandleForPlaneFunc)(struct gbm_bo*, int);
+typedef uint32_t (*GetStrideForPlaneFunc)(struct gbm_bo*, int);
+typedef uint32_t (*GetOffsetFunc)(struct gbm_bo*, int);
+typedef int (*DeviceIsFormatSupportedFunc)(struct gbm_device*, uint32_t,
+                                           uint32_t);
+typedef int (*DrmPrimeHandleToFDFunc)(int, uint32_t, uint32_t, int*);
+typedef struct gbm_surface* (*CreateSurfaceFunc)(struct gbm_device*, uint32_t,
+                                                 uint32_t, uint32_t, uint32_t);
+typedef void (*DestroySurfaceFunc)(struct gbm_surface*);
+
+class GbmLib {
+ public:
+  static bool IsAvailable() { return sLoaded || Load(); }
+  static bool IsModifierAvailable();
+
+  static struct gbm_device* CreateDevice(int fd) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sCreateDevice(fd);
+  };
+  static void DestroyDevice(struct gbm_device* gdm) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sDestroyDevice(gdm);
+  };
+  static struct gbm_bo* Create(struct gbm_device* gbm, uint32_t width,
+                               uint32_t height, uint32_t format,
+                               uint32_t flags) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sCreate(gbm, width, height, format, flags);
+  }
+  static void Destroy(struct gbm_bo* bo) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    sDestroy(bo);
+  }
+  static uint32_t GetStride(struct gbm_bo* bo) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sGetStride(bo);
+  }
+  static int GetFd(struct gbm_bo* bo) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sGetFd(bo);
+  }
+  static void* Map(struct gbm_bo* bo, uint32_t x, uint32_t y, uint32_t width,
+                   uint32_t height, uint32_t flags, uint32_t* stride,
+                   void** map_data) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sMap(bo, x, y, width, height, flags, stride, map_data);
+  }
+  static void Unmap(struct gbm_bo* bo, void* map_data) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    sUnmap(bo, map_data);
+  }
+  static struct gbm_bo* CreateWithModifiers(struct gbm_device* gbm,
+                                            uint32_t width, uint32_t height,
+                                            uint32_t format,
+                                            const uint64_t* modifiers,
+                                            const unsigned int count) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sCreateWithModifiers(gbm, width, height, format, modifiers, count);
+  }
+  static uint64_t GetModifier(struct gbm_bo* bo) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sGetModifier(bo);
+  }
+  static int GetPlaneCount(struct gbm_bo* bo) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sGetPlaneCount(bo);
+  }
+  static union gbm_bo_handle GetHandleForPlane(struct gbm_bo* bo, int plane) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sGetHandleForPlane(bo, plane);
+  }
+  static uint32_t GetStrideForPlane(struct gbm_bo* bo, int plane) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sGetStrideForPlane(bo, plane);
+  }
+  static uint32_t GetOffset(struct gbm_bo* bo, int plane) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sGetOffset(bo, plane);
+  }
+  static int DeviceIsFormatSupported(struct gbm_device* gbm, uint32_t format,
+                                     uint32_t usage) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sDeviceIsFormatSupported(gbm, format, usage);
+  }
+  static int DrmPrimeHandleToFD(int fd, uint32_t handle, uint32_t flags,
+                                int* prime_fd) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sDrmPrimeHandleToFD(fd, handle, flags, prime_fd);
+  }
+  static struct gbm_surface* CreateSurface(struct gbm_device* gbm,
+                                           uint32_t width, uint32_t height,
+                                           uint32_t format, uint32_t flags) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sCreateSurface(gbm, width, height, format, flags);
+  }
+  static void DestroySurface(struct gbm_surface* surface) {
+    StaticMutexAutoLock lockDRI(sDRILock);
+    return sDestroySurface(surface);
+  }
+
+ private:
+  static bool Load();
+  static bool IsLoaded();
+
+  static CreateDeviceFunc sCreateDevice;
+  static DestroyDeviceFunc sDestroyDevice;
+  static CreateFunc sCreate;
+  static CreateWithModifiersFunc sCreateWithModifiers;
+  static GetModifierFunc sGetModifier;
+  static GetStrideFunc sGetStride;
+  static GetFdFunc sGetFd;
+  static DestroyFunc sDestroy;
+  static MapFunc sMap;
+  static UnmapFunc sUnmap;
+  static GetPlaneCountFunc sGetPlaneCount;
+  static GetHandleForPlaneFunc sGetHandleForPlane;
+  static GetStrideForPlaneFunc sGetStrideForPlane;
+  static GetOffsetFunc sGetOffset;
+  static DeviceIsFormatSupportedFunc sDeviceIsFormatSupported;
+  static DrmPrimeHandleToFDFunc sDrmPrimeHandleToFD;
+  static CreateSurfaceFunc sCreateSurface;
+  static DestroySurfaceFunc sDestroySurface;
+  static bool sLoaded;
+
+  static void* sGbmLibHandle;
+  static void* sXf86DrmLibHandle;
+  static mozilla::StaticMutex sDRILock MOZ_UNANNOTATED;
+};
+
+struct GbmFormat {
+  bool mIsSupported;
+  bool mHasAlpha;
+  int mFormat;
+  nsTArray<uint64_t> mModifiers;
+};
+
+class DMABufDevice {
+ public:
+  DMABufDevice();
+  ~DMABufDevice();
+
+  int OpenDRMFd();
+  gbm_device* GetGbmDevice();
+  int GetDmabufFD(uint32_t aGEMHandle);
+
+  bool IsEnabled(nsACString& aFailureId);
+
+  // Use dmabuf for WebRender general web content
+  static bool IsDMABufTexturesEnabled();
+  // Use dmabuf for WebGL content
+  static bool IsDMABufWebGLEnabled();
+  static void DisableDMABufWebGL();
+
+#ifdef MOZ_WAYLAND
+  void AddFormatModifier(bool aHasAlpha, int aFormat, uint32_t mModifierHi,
+                         uint32_t mModifierLo);
+#endif
+  GbmFormat* GetGbmFormat(bool aHasAlpha);
+
+ private:
+  void Configure();
+#ifdef MOZ_WAYLAND
+  void LoadFormatModifiers();
+  void SetModifiersToGfxVars();
+  void GetModifiersFromGfxVars();
+#endif
+
+ private:
+  GbmFormat mXRGBFormat;
+  GbmFormat mARGBFormat;
+
+  int mDRMFd = -1;
+  std::once_flag mFlagGbmDevice;
+  gbm_device* mGbmDevice = nullptr;
+  const char* mFailureId = nullptr;
+  nsAutoCString mDrmRenderNode;
+};
+
+DMABufDevice* GetDMABufDevice();
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // __MOZ_DMABUF_LIB_WRAPPER_H__
diff --git a/widget/gtk/DMABufSurface.cpp b/widget/gtk/DMABufSurface.cpp
new file mode 100644
index 0000000000..b8ec593e30
--- /dev/null
+++ b/widget/gtk/DMABufSurface.cpp
@@ -0,0 +1,1729 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DMABufSurface.h"
+#include "DMABufLibWrapper.h"
+
+#ifdef MOZ_WAYLAND
+#  include "nsWaylandDisplay.h"
+#endif
+
+#include <fcntl.h>
+#include <getopt.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <dlfcn.h>
+#include <sys/mman.h>
+#ifdef HAVE_EVENTFD
+#  include <sys/eventfd.h>
+#endif
+#include <poll.h>
+#ifdef HAVE_SYSIOCCOM_H
+#  include <sys/ioccom.h>
+#endif
+#include <sys/ioctl.h>
+
+#include "mozilla/widget/gbm.h"
+#include "mozilla/widget/va_drmcommon.h"
+#include "YCbCrUtils.h"
+#include "mozilla/gfx/2D.h"
+#include "GLContextTypes.h"  // for GLContext, etc
+#include "GLContextEGL.h"
+#include "GLContextProvider.h"
+#include "ScopedGLHelpers.h"
+#include "GLBlitHelper.h"
+#include "GLReadTexImageHelper.h"
+#include "nsGtkUtils.h"
+
+#include "mozilla/layers/LayersSurfaces.h"
+#include "mozilla/ScopeExit.h"
+
+/*
+TODO:
+DRM device selection:
+https://lists.freedesktop.org/archives/wayland-devel/2018-November/039660.html
+*/
+
+/* C++ / C typecast macros for special EGL handle values */
+#if defined(__cplusplus)
+#  define EGL_CAST(type, value) (static_cast<type>(value))
+#else
+#  define EGL_CAST(type, value) ((type)(value))
+#endif
+
+using namespace mozilla;
+using namespace mozilla::widget;
+using namespace mozilla::gl;
+using namespace mozilla::layers;
+using namespace mozilla::gfx;
+
+#ifdef MOZ_LOGGING
+#  include "mozilla/Logging.h"
+#  include "nsTArray.h"
+#  include "Units.h"
+static LazyLogModule gDmabufRefLog("DmabufRef");
+#  define LOGDMABUFREF(args) \
+    MOZ_LOG(gDmabufRefLog, mozilla::LogLevel::Debug, args)
+#else
+#  define LOGDMABUFREF(args)
+#endif /* MOZ_LOGGING */
+
+#define BUFFER_FLAGS 0
+
+static RefPtr<GLContext> sSnapshotContext;
+static StaticMutex sSnapshotContextMutex MOZ_UNANNOTATED;
+static Atomic<int> gNewSurfaceUID(1);
+
+RefPtr<GLContext> ClaimSnapshotGLContext() {
+  if (!sSnapshotContext) {
+    nsCString discardFailureId;
+    sSnapshotContext = GLContextProvider::CreateHeadless({}, &discardFailureId);
+    if (!sSnapshotContext) {
+      LOGDMABUF(
+          ("ClaimSnapshotGLContext: Failed to create snapshot GLContext."));
+      return nullptr;
+    }
+    sSnapshotContext->mOwningThreadId = Nothing();  // No singular owner.
+  }
+  if (!sSnapshotContext->MakeCurrent()) {
+    LOGDMABUF(("ClaimSnapshotGLContext: Failed to make GLContext current."));
+    return nullptr;
+  }
+  return sSnapshotContext;
+}
+
+void ReturnSnapshotGLContext(RefPtr<GLContext> aGLContext) {
+  // direct eglMakeCurrent() call breaks current context caching so make sure
+  // it's not used.
+  MOZ_ASSERT(!aGLContext->mUseTLSIsCurrent);
+  if (!aGLContext->IsCurrent()) {
+    LOGDMABUF(("ReturnSnapshotGLContext() failed, is not current!"));
+    return;
+  }
+  const auto& gle = gl::GLContextEGL::Cast(aGLContext);
+  const auto& egl = gle->mEgl;
+  egl->fMakeCurrent(EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
+}
+
+bool DMABufSurface::IsGlobalRefSet() const {
+  if (!mGlobalRefCountFd) {
+    return false;
+  }
+  struct pollfd pfd;
+  pfd.fd = mGlobalRefCountFd;
+  pfd.events = POLLIN;
+  return poll(&pfd, 1, 0) == 1;
+}
+
+void DMABufSurface::GlobalRefRelease() {
+#ifdef HAVE_EVENTFD
+  if (!mGlobalRefCountFd) {
+    return;
+  }
+  LOGDMABUFREF(("DMABufSurface::GlobalRefRelease UID %d", mUID));
+  uint64_t counter;
+  if (read(mGlobalRefCountFd, &counter, sizeof(counter)) != sizeof(counter)) {
+    if (errno == EAGAIN) {
+      LOGDMABUFREF(
+          ("  GlobalRefRelease failed: already zero reference! UID %d", mUID));
+    }
+    // EAGAIN means the refcount is already zero. It happens when we release
+    // last reference to the surface.
+    if (errno != EAGAIN) {
+      NS_WARNING(nsPrintfCString("Failed to unref dmabuf global ref count: %s",
+                                 strerror(errno))
+                     .get());
+    }
+  }
+#endif
+}
+
+void DMABufSurface::GlobalRefAdd() {
+#ifdef HAVE_EVENTFD
+  LOGDMABUFREF(("DMABufSurface::GlobalRefAdd UID %d", mUID));
+  MOZ_DIAGNOSTIC_ASSERT(mGlobalRefCountFd);
+  uint64_t counter = 1;
+  if (write(mGlobalRefCountFd, &counter, sizeof(counter)) != sizeof(counter)) {
+    NS_WARNING(nsPrintfCString("Failed to ref dmabuf global ref count: %s",
+                               strerror(errno))
+                   .get());
+  }
+#endif
+}
+
+void DMABufSurface::GlobalRefCountCreate() {
+#ifdef HAVE_EVENTFD
+  LOGDMABUFREF(("DMABufSurface::GlobalRefCountCreate UID %d", mUID));
+  MOZ_DIAGNOSTIC_ASSERT(!mGlobalRefCountFd);
+  // Create global ref count initialized to 0,
+  // i.e. is not referenced after create.
+  mGlobalRefCountFd = eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK | EFD_SEMAPHORE);
+  if (mGlobalRefCountFd < 0) {
+    NS_WARNING(nsPrintfCString("Failed to create dmabuf global ref count: %s",
+                               strerror(errno))
+                   .get());
+    mGlobalRefCountFd = 0;
+    return;
+  }
+#endif
+}
+
+void DMABufSurface::GlobalRefCountImport(int aFd) {
+#ifdef HAVE_EVENTFD
+  mGlobalRefCountFd = aFd;
+  if (mGlobalRefCountFd) {
+    LOGDMABUFREF(("DMABufSurface::GlobalRefCountImport UID %d", mUID));
+    GlobalRefAdd();
+  }
+#endif
+}
+
+int DMABufSurface::GlobalRefCountExport() {
+#ifdef MOZ_LOGGING
+  if (mGlobalRefCountFd) {
+    LOGDMABUFREF(("DMABufSurface::GlobalRefCountExport UID %d", mUID));
+  }
+#endif
+  return mGlobalRefCountFd;
+}
+
+void DMABufSurface::GlobalRefCountDelete() {
+  if (mGlobalRefCountFd) {
+    LOGDMABUFREF(("DMABufSurface::GlobalRefCountDelete UID %d", mUID));
+    close(mGlobalRefCountFd);
+    mGlobalRefCountFd = 0;
+  }
+}
+
+void DMABufSurface::ReleaseDMABuf() {
+  LOGDMABUF(("DMABufSurface::ReleaseDMABuf() UID %d", mUID));
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    Unmap(i);
+  }
+
+  MutexAutoLock lockFD(mSurfaceLock);
+  CloseFileDescriptors(lockFD, /* aForceClose */ true);
+
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    if (mGbmBufferObject[i]) {
+      GbmLib::Destroy(mGbmBufferObject[i]);
+      mGbmBufferObject[i] = nullptr;
+    }
+  }
+  mBufferPlaneCount = 0;
+}
+
+DMABufSurface::DMABufSurface(SurfaceType aSurfaceType)
+    : mSurfaceType(aSurfaceType),
+      mBufferPlaneCount(0),
+      mDrmFormats(),
+      mStrides(),
+      mOffsets(),
+      mGbmBufferObject(),
+      mMappedRegion(),
+      mMappedRegionStride(),
+      mSyncFd(-1),
+      mSync(nullptr),
+      mGlobalRefCountFd(0),
+      mUID(gNewSurfaceUID++),
+      mSurfaceLock("DMABufSurface") {
+  for (auto& slot : mDmabufFds) {
+    slot = -1;
+  }
+  for (auto& modifier : mBufferModifiers) {
+    modifier = DRM_FORMAT_MOD_INVALID;
+  }
+}
+
+DMABufSurface::~DMABufSurface() {
+  FenceDelete();
+  GlobalRefRelease();
+  GlobalRefCountDelete();
+}
+
+already_AddRefed<DMABufSurface> DMABufSurface::CreateDMABufSurface(
+    const mozilla::layers::SurfaceDescriptor& aDesc) {
+  const SurfaceDescriptorDMABuf& desc = aDesc.get_SurfaceDescriptorDMABuf();
+  RefPtr<DMABufSurface> surf;
+
+  switch (desc.bufferType()) {
+    case SURFACE_RGBA:
+      surf = new DMABufSurfaceRGBA();
+      break;
+    case SURFACE_NV12:
+    case SURFACE_YUV420:
+      surf = new DMABufSurfaceYUV();
+      break;
+    default:
+      return nullptr;
+  }
+
+  if (!surf->Create(desc)) {
+    return nullptr;
+  }
+  return surf.forget();
+}
+
+void DMABufSurface::FenceDelete() {
+  if (mSyncFd > 0) {
+    close(mSyncFd);
+    mSyncFd = -1;
+  }
+
+  if (!mGL) {
+    return;
+  }
+  const auto& gle = gl::GLContextEGL::Cast(mGL);
+  const auto& egl = gle->mEgl;
+
+  if (mSync) {
+    egl->fDestroySync(mSync);
+    mSync = nullptr;
+  }
+}
+
+void DMABufSurface::FenceSet() {
+  if (!mGL || !mGL->MakeCurrent()) {
+    MOZ_DIAGNOSTIC_ASSERT(mGL,
+                          "DMABufSurface::FenceSet(): missing GL context!");
+    return;
+  }
+  const auto& gle = gl::GLContextEGL::Cast(mGL);
+  const auto& egl = gle->mEgl;
+
+  if (egl->IsExtensionSupported(EGLExtension::KHR_fence_sync) &&
+      egl->IsExtensionSupported(EGLExtension::ANDROID_native_fence_sync)) {
+    FenceDelete();
+
+    mSync = egl->fCreateSync(LOCAL_EGL_SYNC_NATIVE_FENCE_ANDROID, nullptr);
+    if (mSync) {
+      mSyncFd = egl->fDupNativeFenceFDANDROID(mSync);
+      mGL->fFlush();
+      return;
+    }
+  }
+
+  // ANDROID_native_fence_sync may not be supported so call glFinish()
+  // as a slow path.
+  mGL->fFinish();
+}
+
+void DMABufSurface::FenceWait() {
+  if (!mGL || mSyncFd < 0) {
+    MOZ_DIAGNOSTIC_ASSERT(mGL,
+                          "DMABufSurface::FenceWait() missing GL context!");
+    return;
+  }
+
+  const auto& gle = gl::GLContextEGL::Cast(mGL);
+  const auto& egl = gle->mEgl;
+
+  const EGLint attribs[] = {LOCAL_EGL_SYNC_NATIVE_FENCE_FD_ANDROID, mSyncFd,
+                            LOCAL_EGL_NONE};
+  EGLSync sync = egl->fCreateSync(LOCAL_EGL_SYNC_NATIVE_FENCE_ANDROID, attribs);
+  if (!sync) {
+    MOZ_ASSERT(false, "DMABufSurface::FenceWait(): Failed to create GLFence!");
+    // We failed to create GLFence so clear mSyncFd to avoid another try.
+    close(mSyncFd);
+    mSyncFd = -1;
+    return;
+  }
+
+  // mSyncFd is owned by GLFence so clear local reference to avoid double close
+  // at DMABufSurface::FenceDelete().
+  mSyncFd = -1;
+
+  egl->fClientWaitSync(sync, 0, LOCAL_EGL_FOREVER);
+  egl->fDestroySync(sync);
+}
+
+bool DMABufSurface::OpenFileDescriptors(const MutexAutoLock& aProofOfLock) {
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    if (!OpenFileDescriptorForPlane(aProofOfLock, i)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+// We can safely close DMABuf file descriptors only when we have a valid
+// GbmBufferObject. When we don't have a valid GbmBufferObject and a DMABuf
+// file descriptor is closed, whole surface is released.
+void DMABufSurface::CloseFileDescriptors(const MutexAutoLock& aProofOfLock,
+                                         bool aForceClose) {
+  for (int i = 0; i < DMABUF_BUFFER_PLANES; i++) {
+    CloseFileDescriptorForPlane(aProofOfLock, i, aForceClose);
+  }
+}
+
+DMABufSurfaceRGBA::DMABufSurfaceRGBA()
+    : DMABufSurface(SURFACE_RGBA),
+      mSurfaceFlags(0),
+      mWidth(0),
+      mHeight(0),
+      mGmbFormat(nullptr),
+      mEGLImage(LOCAL_EGL_NO_IMAGE),
+      mTexture(0),
+      mGbmBufferFlags(0) {}
+
+DMABufSurfaceRGBA::~DMABufSurfaceRGBA() {
+#ifdef MOZ_WAYLAND
+  ReleaseWlBuffer();
+#endif
+  ReleaseSurface();
+}
+
+bool DMABufSurfaceRGBA::OpenFileDescriptorForPlane(
+    const MutexAutoLock& aProofOfLock, int aPlane) {
+  if (mDmabufFds[aPlane] >= 0) {
+    return true;
+  }
+  gbm_bo* bo = mGbmBufferObject[0];
+  if (NS_WARN_IF(!bo)) {
+    LOGDMABUF(
+        ("DMABufSurfaceRGBA::OpenFileDescriptorForPlane: Missing "
+         "mGbmBufferObject object!"));
+    return false;
+  }
+
+  if (mBufferPlaneCount == 1) {
+    MOZ_ASSERT(aPlane == 0, "DMABuf: wrong surface plane!");
+    mDmabufFds[0] = GbmLib::GetFd(bo);
+  } else {
+    mDmabufFds[aPlane] = GetDMABufDevice()->GetDmabufFD(
+        GbmLib::GetHandleForPlane(bo, aPlane).u32);
+  }
+
+  if (mDmabufFds[aPlane] < 0) {
+    CloseFileDescriptors(aProofOfLock);
+    return false;
+  }
+
+  return true;
+}
+
+void DMABufSurfaceRGBA::CloseFileDescriptorForPlane(
+    const MutexAutoLock& aProofOfLock, int aPlane, bool aForceClose = false) {
+  if ((aForceClose || mGbmBufferObject[0]) && mDmabufFds[aPlane] >= 0) {
+    close(mDmabufFds[aPlane]);
+    mDmabufFds[aPlane] = -1;
+  }
+}
+
+bool DMABufSurfaceRGBA::Create(int aWidth, int aHeight,
+                               int aDMABufSurfaceFlags) {
+  MOZ_ASSERT(mGbmBufferObject[0] == nullptr, "Already created?");
+
+  mSurfaceFlags = aDMABufSurfaceFlags;
+  mWidth = aWidth;
+  mHeight = aHeight;
+
+  LOGDMABUF(("DMABufSurfaceRGBA::Create() UID %d size %d x %d\n", mUID, mWidth,
+             mHeight));
+
+  if (!GetDMABufDevice()->GetGbmDevice()) {
+    LOGDMABUF(("    Missing GbmDevice!"));
+    return false;
+  }
+
+  mGmbFormat = GetDMABufDevice()->GetGbmFormat(mSurfaceFlags & DMABUF_ALPHA);
+  if (!mGmbFormat) {
+    // Requested DRM format is not supported.
+    return false;
+  }
+  mDrmFormats[0] = mGmbFormat->mFormat;
+
+  bool useModifiers = (aDMABufSurfaceFlags & DMABUF_USE_MODIFIERS) &&
+                      !mGmbFormat->mModifiers.IsEmpty();
+  if (useModifiers) {
+    LOGDMABUF(("    Creating with modifiers\n"));
+    mGbmBufferObject[0] = GbmLib::CreateWithModifiers(
+        GetDMABufDevice()->GetGbmDevice(), mWidth, mHeight, mDrmFormats[0],
+        mGmbFormat->mModifiers.Elements(), mGmbFormat->mModifiers.Length());
+    if (mGbmBufferObject[0]) {
+      mBufferModifiers[0] = GbmLib::GetModifier(mGbmBufferObject[0]);
+    }
+  }
+
+  if (!mGbmBufferObject[0]) {
+    LOGDMABUF(("    Creating without modifiers\n"));
+    mGbmBufferFlags = GBM_BO_USE_LINEAR;
+    mGbmBufferObject[0] =
+        GbmLib::Create(GetDMABufDevice()->GetGbmDevice(), mWidth, mHeight,
+                       mDrmFormats[0], mGbmBufferFlags);
+    mBufferModifiers[0] = DRM_FORMAT_MOD_INVALID;
+  }
+
+  if (!mGbmBufferObject[0]) {
+    LOGDMABUF(("    Failed to create GbmBufferObject\n"));
+    return false;
+  }
+
+  if (mBufferModifiers[0] != DRM_FORMAT_MOD_INVALID) {
+    mBufferPlaneCount = GbmLib::GetPlaneCount(mGbmBufferObject[0]);
+    if (mBufferPlaneCount > DMABUF_BUFFER_PLANES) {
+      LOGDMABUF(
+          ("    There's too many dmabuf planes! (%d)", mBufferPlaneCount));
+      mBufferPlaneCount = DMABUF_BUFFER_PLANES;
+      return false;
+    }
+
+    for (int i = 0; i < mBufferPlaneCount; i++) {
+      mStrides[i] = GbmLib::GetStrideForPlane(mGbmBufferObject[0], i);
+      mOffsets[i] = GbmLib::GetOffset(mGbmBufferObject[0], i);
+    }
+  } else {
+    mBufferPlaneCount = 1;
+    mStrides[0] = GbmLib::GetStride(mGbmBufferObject[0]);
+  }
+
+  LOGDMABUF(("    Success\n"));
+  return true;
+}
+
+bool DMABufSurfaceRGBA::Create(mozilla::gl::GLContext* aGLContext,
+                               const EGLImageKHR aEGLImage, int aWidth,
+                               int aHeight) {
+  LOGDMABUF(("DMABufSurfaceRGBA::Create() from EGLImage UID = %d\n", mUID));
+  if (!aGLContext) {
+    return false;
+  }
+  const auto& gle = gl::GLContextEGL::Cast(aGLContext);
+  const auto& egl = gle->mEgl;
+
+  mGL = aGLContext;
+  mWidth = aWidth;
+  mHeight = aHeight;
+  mEGLImage = aEGLImage;
+  if (!egl->fExportDMABUFImageQuery(mEGLImage, mDrmFormats, &mBufferPlaneCount,
+                                    mBufferModifiers)) {
+    LOGDMABUF(("  ExportDMABUFImageQueryMESA failed, quit\n"));
+    return false;
+  }
+  if (mBufferPlaneCount > DMABUF_BUFFER_PLANES) {
+    LOGDMABUF(("  wrong plane count %d, quit\n", mBufferPlaneCount));
+    mBufferPlaneCount = DMABUF_BUFFER_PLANES;
+    return false;
+  }
+  if (!egl->fExportDMABUFImage(mEGLImage, mDmabufFds, mStrides, mOffsets)) {
+    LOGDMABUF(("  ExportDMABUFImageMESA failed, quit\n"));
+    return false;
+  }
+
+  // A broken driver can return dmabuf without valid file descriptors
+  // which leads to fails later so quit now.
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    if (mDmabufFds[i] < 0) {
+      LOGDMABUF(
+          ("  ExportDMABUFImageMESA failed, mDmabufFds[%d] is invalid, quit",
+           i));
+      return false;
+    }
+  }
+
+  LOGDMABUF(("  imported size %d x %d format %x planes %d modifiers %" PRIx64,
+             mWidth, mHeight, mDrmFormats[0], mBufferPlaneCount,
+             mBufferModifiers[0]));
+  return true;
+}
+
+bool DMABufSurfaceRGBA::ImportSurfaceDescriptor(
+    const SurfaceDescriptor& aDesc) {
+  const SurfaceDescriptorDMABuf& desc = aDesc.get_SurfaceDescriptorDMABuf();
+
+  mWidth = desc.width()[0];
+  mHeight = desc.height()[0];
+  mBufferModifiers[0] = desc.modifier()[0];
+  mDrmFormats[0] = desc.format()[0];
+  mBufferPlaneCount = desc.fds().Length();
+  mGbmBufferFlags = desc.flags();
+  MOZ_RELEASE_ASSERT(mBufferPlaneCount <= DMABUF_BUFFER_PLANES);
+  mUID = desc.uid();
+
+  LOGDMABUF(
+      ("DMABufSurfaceRGBA::ImportSurfaceDescriptor() UID %d size %d x %d\n",
+       mUID, mWidth, mHeight));
+
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    mDmabufFds[i] = desc.fds()[i].ClonePlatformHandle().release();
+    if (mDmabufFds[i] < 0) {
+      LOGDMABUF(
+          ("    failed to get DMABuf file descriptor: %s", strerror(errno)));
+      return false;
+    }
+    mStrides[i] = desc.strides()[i];
+    mOffsets[i] = desc.offsets()[i];
+  }
+
+  if (desc.fence().Length() > 0) {
+    mSyncFd = desc.fence()[0].ClonePlatformHandle().release();
+    if (mSyncFd < 0) {
+      LOGDMABUF(
+          ("    failed to get GL fence file descriptor: %s", strerror(errno)));
+      return false;
+    }
+  }
+
+  if (desc.refCount().Length() > 0) {
+    GlobalRefCountImport(desc.refCount()[0].ClonePlatformHandle().release());
+  }
+
+  LOGDMABUF(("  imported size %d x %d format %x planes %d", mWidth, mHeight,
+             mDrmFormats[0], mBufferPlaneCount));
+  return true;
+}
+
+bool DMABufSurfaceRGBA::Create(const SurfaceDescriptor& aDesc) {
+  return ImportSurfaceDescriptor(aDesc);
+}
+
+bool DMABufSurfaceRGBA::Serialize(
+    mozilla::layers::SurfaceDescriptor& aOutDescriptor) {
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> width;
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> height;
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> format;
+  AutoTArray<ipc::FileDescriptor, DMABUF_BUFFER_PLANES> fds;
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> strides;
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> offsets;
+  AutoTArray<uintptr_t, DMABUF_BUFFER_PLANES> images;
+  AutoTArray<uint64_t, DMABUF_BUFFER_PLANES> modifiers;
+  AutoTArray<ipc::FileDescriptor, 1> fenceFDs;
+  AutoTArray<ipc::FileDescriptor, 1> refCountFDs;
+
+  LOGDMABUF(("DMABufSurfaceRGBA::Serialize() UID %d\n", mUID));
+
+  MutexAutoLock lockFD(mSurfaceLock);
+  if (!OpenFileDescriptors(lockFD)) {
+    return false;
+  }
+
+  width.AppendElement(mWidth);
+  height.AppendElement(mHeight);
+  format.AppendElement(mDrmFormats[0]);
+  modifiers.AppendElement(mBufferModifiers[0]);
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    fds.AppendElement(ipc::FileDescriptor(mDmabufFds[i]));
+    strides.AppendElement(mStrides[i]);
+    offsets.AppendElement(mOffsets[i]);
+  }
+
+  CloseFileDescriptors(lockFD);
+
+  if (mSync) {
+    fenceFDs.AppendElement(ipc::FileDescriptor(mSyncFd));
+  }
+
+  if (mGlobalRefCountFd) {
+    refCountFDs.AppendElement(ipc::FileDescriptor(GlobalRefCountExport()));
+  }
+
+  aOutDescriptor = SurfaceDescriptorDMABuf(
+      mSurfaceType, modifiers, mGbmBufferFlags, fds, width, height, width,
+      height, format, strides, offsets, GetYUVColorSpace(), mColorRange,
+      fenceFDs, mUID, refCountFDs);
+  return true;
+}
+
+bool DMABufSurfaceRGBA::CreateTexture(GLContext* aGLContext, int aPlane) {
+  LOGDMABUF(("DMABufSurfaceRGBA::CreateTexture() UID %d\n", mUID));
+  MOZ_ASSERT(!mEGLImage && !mTexture, "EGLImage is already created!");
+
+  nsTArray<EGLint> attribs;
+  attribs.AppendElement(LOCAL_EGL_WIDTH);
+  attribs.AppendElement(mWidth);
+  attribs.AppendElement(LOCAL_EGL_HEIGHT);
+  attribs.AppendElement(mHeight);
+  attribs.AppendElement(LOCAL_EGL_LINUX_DRM_FOURCC_EXT);
+  attribs.AppendElement(mDrmFormats[0]);
+#define ADD_PLANE_ATTRIBS(plane_idx)                                        \
+  {                                                                         \
+    attribs.AppendElement(LOCAL_EGL_DMA_BUF_PLANE##plane_idx##_FD_EXT);     \
+    attribs.AppendElement(mDmabufFds[plane_idx]);                           \
+    attribs.AppendElement(LOCAL_EGL_DMA_BUF_PLANE##plane_idx##_OFFSET_EXT); \
+    attribs.AppendElement((int)mOffsets[plane_idx]);                        \
+    attribs.AppendElement(LOCAL_EGL_DMA_BUF_PLANE##plane_idx##_PITCH_EXT);  \
+    attribs.AppendElement((int)mStrides[plane_idx]);                        \
+    if (mBufferModifiers[0] != DRM_FORMAT_MOD_INVALID) {                    \
+      attribs.AppendElement(                                                \
+          LOCAL_EGL_DMA_BUF_PLANE##plane_idx##_MODIFIER_LO_EXT);            \
+      attribs.AppendElement(mBufferModifiers[0] & 0xFFFFFFFF);              \
+      attribs.AppendElement(                                                \
+          LOCAL_EGL_DMA_BUF_PLANE##plane_idx##_MODIFIER_HI_EXT);            \
+      attribs.AppendElement(mBufferModifiers[0] >> 32);                     \
+    }                                                                       \
+  }
+
+  MutexAutoLock lockFD(mSurfaceLock);
+  if (!OpenFileDescriptors(lockFD)) {
+    return false;
+  }
+  ADD_PLANE_ATTRIBS(0);
+  if (mBufferPlaneCount > 1) ADD_PLANE_ATTRIBS(1);
+  if (mBufferPlaneCount > 2) ADD_PLANE_ATTRIBS(2);
+  if (mBufferPlaneCount > 3) ADD_PLANE_ATTRIBS(3);
+#undef ADD_PLANE_ATTRIBS
+  attribs.AppendElement(LOCAL_EGL_NONE);
+
+  if (!aGLContext) return false;
+
+  if (!aGLContext->MakeCurrent()) {
+    LOGDMABUF(
+        ("DMABufSurfaceRGBA::CreateTexture(): failed to make GL context "
+         "current"));
+    return false;
+  }
+
+  const auto& gle = gl::GLContextEGL::Cast(aGLContext);
+  const auto& egl = gle->mEgl;
+  mEGLImage =
+      egl->fCreateImage(LOCAL_EGL_NO_CONTEXT, LOCAL_EGL_LINUX_DMA_BUF_EXT,
+                        nullptr, attribs.Elements());
+
+  CloseFileDescriptors(lockFD);
+
+  if (mEGLImage == LOCAL_EGL_NO_IMAGE) {
+    LOGDMABUF(("EGLImageKHR creation failed"));
+    return false;
+  }
+
+  aGLContext->fGenTextures(1, &mTexture);
+  const ScopedBindTexture savedTex(aGLContext, mTexture);
+  aGLContext->fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_WRAP_S,
+                             LOCAL_GL_CLAMP_TO_EDGE);
+  aGLContext->fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_WRAP_T,
+                             LOCAL_GL_CLAMP_TO_EDGE);
+  aGLContext->fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_MAG_FILTER,
+                             LOCAL_GL_LINEAR);
+  aGLContext->fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_MIN_FILTER,
+                             LOCAL_GL_LINEAR);
+  aGLContext->fEGLImageTargetTexture2D(LOCAL_GL_TEXTURE_2D, mEGLImage);
+  mGL = aGLContext;
+
+  return true;
+}
+
+void DMABufSurfaceRGBA::ReleaseTextures() {
+  LOGDMABUF(("DMABufSurfaceRGBA::ReleaseTextures() UID %d\n", mUID));
+  FenceDelete();
+
+  if (!mTexture && !mEGLImage) {
+    return;
+  }
+
+  if (!mGL) {
+#ifdef NIGHTLY_BUILD
+    MOZ_DIAGNOSTIC_ASSERT(mGL, "Missing GL context!");
+#else
+    NS_WARNING(
+        "DMABufSurfaceRGBA::ReleaseTextures(): Missing GL context! We're "
+        "leaking textures!");
+    return;
+#endif
+  }
+
+  const auto& gle = gl::GLContextEGL::Cast(mGL);
+  const auto& egl = gle->mEgl;
+
+  if (mTexture && mGL->MakeCurrent()) {
+    mGL->fDeleteTextures(1, &mTexture);
+    mTexture = 0;
+  }
+
+  if (mEGLImage != LOCAL_EGL_NO_IMAGE) {
+    egl->fDestroyImage(mEGLImage);
+    mEGLImage = LOCAL_EGL_NO_IMAGE;
+  }
+  mGL = nullptr;
+}
+
+void DMABufSurfaceRGBA::ReleaseSurface() {
+  MOZ_ASSERT(!IsMapped(), "We can't release mapped buffer!");
+
+  ReleaseTextures();
+  ReleaseDMABuf();
+}
+
+#ifdef MOZ_WAYLAND
+bool DMABufSurfaceRGBA::CreateWlBuffer() {
+  MutexAutoLock lockFD(mSurfaceLock);
+  if (!OpenFileDescriptors(lockFD)) {
+    return false;
+  }
+
+  nsWaylandDisplay* waylandDisplay = widget::WaylandDisplayGet();
+  if (!waylandDisplay->GetDmabuf()) {
+    CloseFileDescriptors(lockFD);
+    return false;
+  }
+
+  struct zwp_linux_buffer_params_v1* params =
+      zwp_linux_dmabuf_v1_create_params(waylandDisplay->GetDmabuf());
+  zwp_linux_buffer_params_v1_add(params, mDmabufFds[0], 0, mOffsets[0],
+                                 mStrides[0], mBufferModifiers[0] >> 32,
+                                 mBufferModifiers[0] & 0xffffffff);
+
+  mWlBuffer = zwp_linux_buffer_params_v1_create_immed(
+      params, GetWidth(), GetHeight(), mDrmFormats[0], 0);
+
+  CloseFileDescriptors(lockFD);
+
+  return mWlBuffer != nullptr;
+}
+
+void DMABufSurfaceRGBA::ReleaseWlBuffer() {
+  MozClearPointer(mWlBuffer, wl_buffer_destroy);
+}
+#endif
+
+// We should synchronize DMA Buffer object access from CPU to avoid potential
+// cache incoherency and data loss.
+// See
+// https://01.org/linuxgraphics/gfx-docs/drm/driver-api/dma-buf.html#cpu-access-to-dma-buffer-objects
+struct dma_buf_sync {
+  uint64_t flags;
+};
+#define DMA_BUF_SYNC_READ (1 << 0)
+#define DMA_BUF_SYNC_WRITE (2 << 0)
+#define DMA_BUF_SYNC_START (0 << 2)
+#define DMA_BUF_SYNC_END (1 << 2)
+#define DMA_BUF_BASE 'b'
+#define DMA_BUF_IOCTL_SYNC _IOW(DMA_BUF_BASE, 0, struct dma_buf_sync)
+
+static void SyncDmaBuf(int aFd, uint64_t aFlags) {
+  struct dma_buf_sync sync = {0};
+
+  sync.flags = aFlags | DMA_BUF_SYNC_READ | DMA_BUF_SYNC_WRITE;
+  while (true) {
+    int ret;
+    ret = ioctl(aFd, DMA_BUF_IOCTL_SYNC, &sync);
+    if (ret == -1 && errno == EINTR) {
+      continue;
+    } else if (ret == -1) {
+      LOGDMABUF(
+          ("Failed to synchronize DMA buffer: %s FD %d", strerror(errno), aFd));
+      break;
+    } else {
+      break;
+    }
+  }
+}
+
+void* DMABufSurface::MapInternal(uint32_t aX, uint32_t aY, uint32_t aWidth,
+                                 uint32_t aHeight, uint32_t* aStride,
+                                 int aGbmFlags, int aPlane) {
+  NS_ASSERTION(!IsMapped(aPlane), "Already mapped!");
+  if (!mGbmBufferObject[aPlane]) {
+    NS_WARNING("We can't map DMABufSurfaceRGBA without mGbmBufferObject");
+    return nullptr;
+  }
+
+  LOGDMABUF(
+      ("DMABufSurfaceRGBA::MapInternal() UID %d plane %d size %d x %d -> %d x "
+       "%d\n",
+       mUID, aPlane, aX, aY, aWidth, aHeight));
+
+  mMappedRegionStride[aPlane] = 0;
+  mMappedRegionData[aPlane] = nullptr;
+  mMappedRegion[aPlane] =
+      GbmLib::Map(mGbmBufferObject[aPlane], aX, aY, aWidth, aHeight, aGbmFlags,
+                  &mMappedRegionStride[aPlane], &mMappedRegionData[aPlane]);
+  if (!mMappedRegion[aPlane]) {
+    LOGDMABUF(("    Surface mapping failed: %s", strerror(errno)));
+    return nullptr;
+  }
+  if (aStride) {
+    *aStride = mMappedRegionStride[aPlane];
+  }
+
+  MutexAutoLock lockFD(mSurfaceLock);
+  if (OpenFileDescriptorForPlane(lockFD, aPlane)) {
+    SyncDmaBuf(mDmabufFds[aPlane], DMA_BUF_SYNC_START);
+    CloseFileDescriptorForPlane(lockFD, aPlane);
+  }
+
+  return mMappedRegion[aPlane];
+}
+
+void* DMABufSurfaceRGBA::MapReadOnly(uint32_t aX, uint32_t aY, uint32_t aWidth,
+                                     uint32_t aHeight, uint32_t* aStride) {
+  return MapInternal(aX, aY, aWidth, aHeight, aStride, GBM_BO_TRANSFER_READ);
+}
+
+void* DMABufSurfaceRGBA::MapReadOnly(uint32_t* aStride) {
+  return MapInternal(0, 0, mWidth, mHeight, aStride, GBM_BO_TRANSFER_READ);
+}
+
+void* DMABufSurfaceRGBA::Map(uint32_t aX, uint32_t aY, uint32_t aWidth,
+                             uint32_t aHeight, uint32_t* aStride) {
+  return MapInternal(aX, aY, aWidth, aHeight, aStride,
+                     GBM_BO_TRANSFER_READ_WRITE);
+}
+
+void* DMABufSurfaceRGBA::Map(uint32_t* aStride) {
+  return MapInternal(0, 0, mWidth, mHeight, aStride,
+                     GBM_BO_TRANSFER_READ_WRITE);
+}
+
+void DMABufSurface::Unmap(int aPlane) {
+  if (mMappedRegion[aPlane]) {
+    LOGDMABUF(("DMABufSurface::Unmap() UID %d plane %d\n", mUID, aPlane));
+    MutexAutoLock lockFD(mSurfaceLock);
+    if (OpenFileDescriptorForPlane(lockFD, aPlane)) {
+      SyncDmaBuf(mDmabufFds[aPlane], DMA_BUF_SYNC_END);
+      CloseFileDescriptorForPlane(lockFD, aPlane);
+    }
+    GbmLib::Unmap(mGbmBufferObject[aPlane], mMappedRegionData[aPlane]);
+    mMappedRegion[aPlane] = nullptr;
+    mMappedRegionData[aPlane] = nullptr;
+    mMappedRegionStride[aPlane] = 0;
+  }
+}
+
+nsresult DMABufSurface::BuildSurfaceDescriptorBuffer(
+    SurfaceDescriptorBuffer& aSdBuffer, Image::BuildSdbFlags aFlags,
+    const std::function<MemoryOrShmem(uint32_t)>& aAllocate) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+#ifdef DEBUG
+void DMABufSurfaceRGBA::DumpToFile(const char* pFile) {
+  uint32_t stride;
+
+  if (!MapReadOnly(&stride)) {
+    return;
+  }
+  cairo_surface_t* surface = nullptr;
+
+  auto unmap = MakeScopeExit([&] {
+    if (surface) {
+      cairo_surface_destroy(surface);
+    }
+    Unmap();
+  });
+
+  surface = cairo_image_surface_create_for_data(
+      (unsigned char*)mMappedRegion[0], CAIRO_FORMAT_ARGB32, mWidth, mHeight,
+      stride);
+  if (cairo_surface_status(surface) == CAIRO_STATUS_SUCCESS) {
+    cairo_surface_write_to_png(surface, pFile);
+  }
+}
+#endif
+
+#if 0
+// Copy from source surface by GL
+#  include "GLBlitHelper.h"
+
+bool DMABufSurfaceRGBA::CopyFrom(class DMABufSurface* aSourceSurface,
+                                 GLContext* aGLContext) {
+  MOZ_ASSERT(aSourceSurface->GetTexture());
+  MOZ_ASSERT(GetTexture());
+
+  gfx::IntSize size(GetWidth(), GetHeight());
+  aGLContext->BlitHelper()->BlitTextureToTexture(aSourceSurface->GetTexture(),
+    GetTexture(), size, size);
+  return true;
+}
+#endif
+
+// TODO - Clear the surface by EGL
+void DMABufSurfaceRGBA::Clear() {
+  uint32_t destStride;
+  void* destData = Map(&destStride);
+  memset(destData, 0, GetHeight() * destStride);
+  Unmap();
+}
+
+bool DMABufSurfaceRGBA::HasAlpha() {
+  return !mGmbFormat || mGmbFormat->mHasAlpha;
+}
+
+gfx::SurfaceFormat DMABufSurfaceRGBA::GetFormat() {
+  return HasAlpha() ? gfx::SurfaceFormat::B8G8R8A8
+                    : gfx::SurfaceFormat::B8G8R8X8;
+}
+
+// GL uses swapped R and B components so report accordingly.
+gfx::SurfaceFormat DMABufSurfaceRGBA::GetFormatGL() {
+  return HasAlpha() ? gfx::SurfaceFormat::R8G8B8A8
+                    : gfx::SurfaceFormat::R8G8B8X8;
+}
+
+already_AddRefed<DMABufSurfaceRGBA> DMABufSurfaceRGBA::CreateDMABufSurface(
+    int aWidth, int aHeight, int aDMABufSurfaceFlags) {
+  RefPtr<DMABufSurfaceRGBA> surf = new DMABufSurfaceRGBA();
+  if (!surf->Create(aWidth, aHeight, aDMABufSurfaceFlags)) {
+    return nullptr;
+  }
+  return surf.forget();
+}
+
+already_AddRefed<DMABufSurface> DMABufSurfaceRGBA::CreateDMABufSurface(
+    mozilla::gl::GLContext* aGLContext, const EGLImageKHR aEGLImage, int aWidth,
+    int aHeight) {
+  RefPtr<DMABufSurfaceRGBA> surf = new DMABufSurfaceRGBA();
+  if (!surf->Create(aGLContext, aEGLImage, aWidth, aHeight)) {
+    return nullptr;
+  }
+  return surf.forget();
+}
+
+already_AddRefed<DMABufSurfaceYUV> DMABufSurfaceYUV::CreateYUVSurface(
+    const VADRMPRIMESurfaceDescriptor& aDesc, int aWidth, int aHeight) {
+  RefPtr<DMABufSurfaceYUV> surf = new DMABufSurfaceYUV();
+  LOGDMABUF(("DMABufSurfaceYUV::CreateYUVSurface() UID %d from desc\n",
+             surf->GetUID()));
+  if (!surf->UpdateYUVData(aDesc, aWidth, aHeight, /* aCopy */ false)) {
+    return nullptr;
+  }
+  return surf.forget();
+}
+
+already_AddRefed<DMABufSurfaceYUV> DMABufSurfaceYUV::CopyYUVSurface(
+    const VADRMPRIMESurfaceDescriptor& aDesc, int aWidth, int aHeight) {
+  RefPtr<DMABufSurfaceYUV> surf = new DMABufSurfaceYUV();
+  LOGDMABUF(("DMABufSurfaceYUV::CreateYUVSurfaceCopy() UID %d from desc\n",
+             surf->GetUID()));
+  if (!surf->UpdateYUVData(aDesc, aWidth, aHeight, /* aCopy */ true)) {
+    return nullptr;
+  }
+  return surf.forget();
+}
+
+already_AddRefed<DMABufSurfaceYUV> DMABufSurfaceYUV::CreateYUVSurface(
+    int aWidth, int aHeight, void** aPixelData, int* aLineSizes) {
+  RefPtr<DMABufSurfaceYUV> surf = new DMABufSurfaceYUV();
+  LOGDMABUF(("DMABufSurfaceYUV::CreateYUVSurface() UID %d %d x %d\n",
+             surf->GetUID(), aWidth, aHeight));
+  if (!surf->Create(aWidth, aHeight, aPixelData, aLineSizes)) {
+    return nullptr;
+  }
+  return surf.forget();
+}
+
+DMABufSurfaceYUV::DMABufSurfaceYUV()
+    : DMABufSurface(SURFACE_NV12),
+      mWidth(),
+      mHeight(),
+      mWidthAligned(),
+      mHeightAligned(),
+      mTexture() {
+  for (int i = 0; i < DMABUF_BUFFER_PLANES; i++) {
+    mEGLImage[i] = LOCAL_EGL_NO_IMAGE;
+  }
+}
+
+DMABufSurfaceYUV::~DMABufSurfaceYUV() { ReleaseSurface(); }
+
+bool DMABufSurfaceYUV::OpenFileDescriptorForPlane(
+    const MutexAutoLock& aProofOfLock, int aPlane) {
+  // The fd is already opened, no need to reopen.
+  // This can happen when we import dmabuf surface from VA-API decoder,
+  // mGbmBufferObject is null and we don't close
+  // file descriptors for surface as they are our only reference to it.
+  if (mDmabufFds[aPlane] >= 0) {
+    return true;
+  }
+
+  if (mGbmBufferObject[aPlane] == nullptr) {
+    LOGDMABUF(
+        ("DMABufSurfaceYUV::OpenFileDescriptorForPlane: Missing "
+         "mGbmBufferObject object!"));
+    return false;
+  }
+
+  mDmabufFds[aPlane] = GbmLib::GetFd(mGbmBufferObject[aPlane]);
+  if (mDmabufFds[aPlane] < 0) {
+    CloseFileDescriptors(aProofOfLock);
+    return false;
+  }
+  return true;
+}
+
+void DMABufSurfaceYUV::CloseFileDescriptorForPlane(
+    const MutexAutoLock& aProofOfLock, int aPlane, bool aForceClose = false) {
+  if ((aForceClose || mGbmBufferObject[aPlane]) && mDmabufFds[aPlane] >= 0) {
+    close(mDmabufFds[aPlane]);
+    mDmabufFds[aPlane] = -1;
+  }
+}
+
+bool DMABufSurfaceYUV::ImportPRIMESurfaceDescriptor(
+    const VADRMPRIMESurfaceDescriptor& aDesc, int aWidth, int aHeight) {
+  LOGDMABUF(("DMABufSurfaceYUV::ImportPRIMESurfaceDescriptor() UID %d", mUID));
+  // Already exists?
+  MOZ_DIAGNOSTIC_ASSERT(mDmabufFds[0] < 0);
+
+  if (aDesc.num_layers > DMABUF_BUFFER_PLANES ||
+      aDesc.num_objects > DMABUF_BUFFER_PLANES) {
+    LOGDMABUF(("  Can't import, wrong layers/objects number (%d, %d)",
+               aDesc.num_layers, aDesc.num_objects));
+    return false;
+  }
+  if (aDesc.fourcc == VA_FOURCC_NV12) {
+    mSurfaceType = SURFACE_NV12;
+  } else if (aDesc.fourcc == VA_FOURCC_P010) {
+    mSurfaceType = SURFACE_NV12;
+  } else if (aDesc.fourcc == VA_FOURCC_YV12) {
+    mSurfaceType = SURFACE_YUV420;
+  } else {
+    LOGDMABUF(("  Can't import surface data of 0x%x format", aDesc.fourcc));
+    return false;
+  }
+
+  mBufferPlaneCount = aDesc.num_layers;
+
+  for (unsigned int i = 0; i < aDesc.num_layers; i++) {
+    // All supported formats have 4:2:0 chroma sub-sampling.
+    unsigned int subsample = i == 0 ? 0 : 1;
+
+    unsigned int object = aDesc.layers[i].object_index[0];
+    mBufferModifiers[i] = aDesc.objects[object].drm_format_modifier;
+    mDrmFormats[i] = aDesc.layers[i].drm_format;
+    mOffsets[i] = aDesc.layers[i].offset[0];
+    mStrides[i] = aDesc.layers[i].pitch[0];
+    mWidthAligned[i] = aDesc.width >> subsample;
+    mHeightAligned[i] = aDesc.height >> subsample;
+    mWidth[i] = aWidth >> subsample;
+    mHeight[i] = aHeight >> subsample;
+    LOGDMABUF(("    plane %d size %d x %d format %x", i, mWidth[i], mHeight[i],
+               mDrmFormats[i]));
+  }
+  return true;
+}
+
+bool DMABufSurfaceYUV::MoveYUVDataImpl(const VADRMPRIMESurfaceDescriptor& aDesc,
+                                       int aWidth, int aHeight) {
+  if (!ImportPRIMESurfaceDescriptor(aDesc, aWidth, aHeight)) {
+    return false;
+  }
+  for (unsigned int i = 0; i < aDesc.num_layers; i++) {
+    unsigned int object = aDesc.layers[i].object_index[0];
+    // Keep VADRMPRIMESurfaceDescriptor untouched and dup() dmabuf
+    // file descriptors.
+    mDmabufFds[i] = dup(aDesc.objects[object].fd);
+  }
+  return true;
+}
+
+void DMABufSurfaceYUV::ReleaseVADRMPRIMESurfaceDescriptor(
+    VADRMPRIMESurfaceDescriptor& aDesc) {
+  for (unsigned int i = 0; i < aDesc.num_layers; i++) {
+    unsigned int object = aDesc.layers[i].object_index[0];
+    if (aDesc.objects[object].fd != -1) {
+      close(aDesc.objects[object].fd);
+      aDesc.objects[object].fd = -1;
+    }
+  }
+}
+
+bool DMABufSurfaceYUV::CreateYUVPlane(int aPlane) {
+  LOGDMABUF(("DMABufSurfaceYUV::CreateYUVPlane() UID %d size %d x %d", mUID,
+             mWidth[aPlane], mHeight[aPlane]));
+
+  if (!GetDMABufDevice()->GetGbmDevice()) {
+    LOGDMABUF(("    Missing GbmDevice!"));
+    return false;
+  }
+
+  MOZ_DIAGNOSTIC_ASSERT(mGbmBufferObject[aPlane] == nullptr);
+  bool useModifiers = (mBufferModifiers[aPlane] != DRM_FORMAT_MOD_INVALID);
+  if (useModifiers) {
+    LOGDMABUF(("    Creating with modifiers"));
+    mGbmBufferObject[aPlane] = GbmLib::CreateWithModifiers(
+        GetDMABufDevice()->GetGbmDevice(), mWidth[aPlane], mHeight[aPlane],
+        mDrmFormats[aPlane], mBufferModifiers + aPlane, 1);
+  }
+  if (!mGbmBufferObject[aPlane]) {
+    LOGDMABUF(("    Creating without modifiers"));
+    mGbmBufferObject[aPlane] = GbmLib::Create(
+        GetDMABufDevice()->GetGbmDevice(), mWidth[aPlane], mHeight[aPlane],
+        mDrmFormats[aPlane], GBM_BO_USE_RENDERING);
+    mBufferModifiers[aPlane] = DRM_FORMAT_MOD_INVALID;
+  }
+  if (!mGbmBufferObject[aPlane]) {
+    LOGDMABUF(("    Failed to create GbmBufferObject: %s", strerror(errno)));
+    return false;
+  }
+
+  mStrides[aPlane] = GbmLib::GetStride(mGbmBufferObject[aPlane]);
+  mOffsets[aPlane] = GbmLib::GetOffset(mGbmBufferObject[aPlane], 0);
+  mWidthAligned[aPlane] = mWidth[aPlane];
+  mHeightAligned[aPlane] = mHeight[aPlane];
+  return true;
+}
+
+bool DMABufSurfaceYUV::CopyYUVDataImpl(const VADRMPRIMESurfaceDescriptor& aDesc,
+                                       int aWidth, int aHeight) {
+  RefPtr<DMABufSurfaceYUV> tmpSurf = CreateYUVSurface(aDesc, aWidth, aHeight);
+  if (!tmpSurf) {
+    return false;
+  }
+
+  if (!ImportPRIMESurfaceDescriptor(aDesc, aWidth, aHeight)) {
+    return false;
+  }
+
+  StaticMutexAutoLock lock(sSnapshotContextMutex);
+  RefPtr<GLContext> context = ClaimSnapshotGLContext();
+  auto releaseTextures = MakeScopeExit([&] {
+    tmpSurf->ReleaseTextures();
+    ReleaseTextures();
+    ReturnSnapshotGLContext(context);
+  });
+
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    if (!tmpSurf->CreateTexture(context, i)) {
+      return false;
+    }
+    if (!CreateYUVPlane(i) || !CreateTexture(context, i)) {
+      return false;
+    }
+    gfx::IntSize size(GetWidth(i), GetHeight(i));
+    context->BlitHelper()->BlitTextureToTexture(
+        tmpSurf->GetTexture(i), GetTexture(i), size, size, LOCAL_GL_TEXTURE_2D,
+        LOCAL_GL_TEXTURE_2D);
+  }
+  return true;
+}
+
+bool DMABufSurfaceYUV::UpdateYUVData(const VADRMPRIMESurfaceDescriptor& aDesc,
+                                     int aWidth, int aHeight, bool aCopy) {
+  LOGDMABUF(("DMABufSurfaceYUV::UpdateYUVData() UID %d copy %d", mUID, aCopy));
+  return aCopy ? CopyYUVDataImpl(aDesc, aWidth, aHeight)
+               : MoveYUVDataImpl(aDesc, aWidth, aHeight);
+}
+
+bool DMABufSurfaceYUV::CreateLinearYUVPlane(int aPlane, int aWidth, int aHeight,
+                                            int aDrmFormat) {
+  LOGDMABUF(("DMABufSurfaceYUV::CreateLinearYUVPlane() UID %d size %d x %d",
+             mUID, aWidth, aHeight));
+
+  if (!GetDMABufDevice()->GetGbmDevice()) {
+    LOGDMABUF(("    Missing GbmDevice!"));
+    return false;
+  }
+
+  mWidth[aPlane] = aWidth;
+  mHeight[aPlane] = aHeight;
+  mDrmFormats[aPlane] = aDrmFormat;
+
+  mGbmBufferObject[aPlane] =
+      GbmLib::Create(GetDMABufDevice()->GetGbmDevice(), aWidth, aHeight,
+                     aDrmFormat, GBM_BO_USE_LINEAR);
+  if (!mGbmBufferObject[aPlane]) {
+    LOGDMABUF(("    Failed to create GbmBufferObject: %s", strerror(errno)));
+    return false;
+  }
+
+  mStrides[aPlane] = GbmLib::GetStride(mGbmBufferObject[aPlane]);
+  mDmabufFds[aPlane] = -1;
+
+  return true;
+}
+
+void DMABufSurfaceYUV::UpdateYUVPlane(int aPlane, void* aPixelData,
+                                      int aLineSize) {
+  LOGDMABUF(
+      ("DMABufSurfaceYUV::UpdateYUVPlane() UID %d plane %d", mUID, aPlane));
+  if (aLineSize == mWidth[aPlane] &&
+      (int)mMappedRegionStride[aPlane] == mWidth[aPlane]) {
+    memcpy(mMappedRegion[aPlane], aPixelData, aLineSize * mHeight[aPlane]);
+  } else {
+    char* src = (char*)aPixelData;
+    char* dest = (char*)mMappedRegion[aPlane];
+    for (int i = 0; i < mHeight[aPlane]; i++) {
+      memcpy(dest, src, mWidth[aPlane]);
+      src += aLineSize;
+      dest += mMappedRegionStride[aPlane];
+    }
+  }
+}
+
+bool DMABufSurfaceYUV::UpdateYUVData(void** aPixelData, int* aLineSizes) {
+  LOGDMABUF(("DMABufSurfaceYUV::UpdateYUVData() UID %d", mUID));
+  if (mSurfaceType != SURFACE_YUV420) {
+    LOGDMABUF(("    UpdateYUVData can upload YUV420 surface type only!"));
+    return false;
+  }
+
+  if (mBufferPlaneCount != 3) {
+    LOGDMABUF(("    DMABufSurfaceYUV planes does not match!"));
+    return false;
+  }
+
+  auto unmapBuffers = MakeScopeExit([&] {
+    Unmap(0);
+    Unmap(1);
+    Unmap(2);
+  });
+
+  // Map planes
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    MapInternal(0, 0, mWidth[i], mHeight[i], nullptr, GBM_BO_TRANSFER_WRITE, i);
+    if (!mMappedRegion[i]) {
+      LOGDMABUF(("    DMABufSurfaceYUV plane can't be mapped!"));
+      return false;
+    }
+    if ((int)mMappedRegionStride[i] < mWidth[i]) {
+      LOGDMABUF(("    DMABufSurfaceYUV plane size stride does not match!"));
+      return false;
+    }
+  }
+
+  // Copy planes
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    UpdateYUVPlane(i, aPixelData[i], aLineSizes[i]);
+  }
+
+  return true;
+}
+
+bool DMABufSurfaceYUV::Create(int aWidth, int aHeight, void** aPixelData,
+                              int* aLineSizes) {
+  LOGDMABUF(("DMABufSurfaceYUV::Create() UID %d size %d x %d", mUID, aWidth,
+             aHeight));
+
+  mSurfaceType = SURFACE_YUV420;
+  mBufferPlaneCount = 3;
+
+  if (!CreateLinearYUVPlane(0, aWidth, aHeight, GBM_FORMAT_R8)) {
+    return false;
+  }
+  if (!CreateLinearYUVPlane(1, aWidth >> 1, aHeight >> 1, GBM_FORMAT_R8)) {
+    return false;
+  }
+  if (!CreateLinearYUVPlane(2, aWidth >> 1, aHeight >> 1, GBM_FORMAT_R8)) {
+    return false;
+  }
+  if (!aPixelData || !aLineSizes) {
+    return true;
+  }
+  return UpdateYUVData(aPixelData, aLineSizes);
+}
+
+bool DMABufSurfaceYUV::Create(const SurfaceDescriptor& aDesc) {
+  return ImportSurfaceDescriptor(aDesc);
+}
+
+bool DMABufSurfaceYUV::ImportSurfaceDescriptor(
+    const SurfaceDescriptorDMABuf& aDesc) {
+  mBufferPlaneCount = aDesc.fds().Length();
+  mSurfaceType = (mBufferPlaneCount == 2) ? SURFACE_NV12 : SURFACE_YUV420;
+  mColorSpace = aDesc.yUVColorSpace();
+  mColorRange = aDesc.colorRange();
+  mUID = aDesc.uid();
+
+  LOGDMABUF(("DMABufSurfaceYUV::ImportSurfaceDescriptor() UID %d", mUID));
+
+  MOZ_RELEASE_ASSERT(mBufferPlaneCount <= DMABUF_BUFFER_PLANES);
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    mDmabufFds[i] = aDesc.fds()[i].ClonePlatformHandle().release();
+    if (mDmabufFds[i] < 0) {
+      LOGDMABUF(("    failed to get DMABuf plane file descriptor: %s",
+                 strerror(errno)));
+      return false;
+    }
+    mWidth[i] = aDesc.width()[i];
+    mHeight[i] = aDesc.height()[i];
+    mWidthAligned[i] = aDesc.widthAligned()[i];
+    mHeightAligned[i] = aDesc.heightAligned()[i];
+    mDrmFormats[i] = aDesc.format()[i];
+    mStrides[i] = aDesc.strides()[i];
+    mOffsets[i] = aDesc.offsets()[i];
+    mBufferModifiers[i] = aDesc.modifier()[i];
+    LOGDMABUF(("    plane %d fd %d size %d x %d format %x", i, mDmabufFds[i],
+               mWidth[i], mHeight[i], mDrmFormats[i]));
+  }
+
+  if (aDesc.fence().Length() > 0) {
+    mSyncFd = aDesc.fence()[0].ClonePlatformHandle().release();
+    if (mSyncFd < 0) {
+      LOGDMABUF(
+          ("    failed to get GL fence file descriptor: %s", strerror(errno)));
+      return false;
+    }
+  }
+
+  if (aDesc.refCount().Length() > 0) {
+    GlobalRefCountImport(aDesc.refCount()[0].ClonePlatformHandle().release());
+  }
+
+  return true;
+}
+
+bool DMABufSurfaceYUV::Serialize(
+    mozilla::layers::SurfaceDescriptor& aOutDescriptor) {
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> width;
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> height;
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> widthBytes;
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> heightBytes;
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> format;
+  AutoTArray<ipc::FileDescriptor, DMABUF_BUFFER_PLANES> fds;
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> strides;
+  AutoTArray<uint32_t, DMABUF_BUFFER_PLANES> offsets;
+  AutoTArray<uint64_t, DMABUF_BUFFER_PLANES> modifiers;
+  AutoTArray<ipc::FileDescriptor, 1> fenceFDs;
+  AutoTArray<ipc::FileDescriptor, 1> refCountFDs;
+
+  LOGDMABUF(("DMABufSurfaceYUV::Serialize() UID %d", mUID));
+
+  MutexAutoLock lockFD(mSurfaceLock);
+  if (!OpenFileDescriptors(lockFD)) {
+    return false;
+  }
+
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    width.AppendElement(mWidth[i]);
+    height.AppendElement(mHeight[i]);
+    widthBytes.AppendElement(mWidthAligned[i]);
+    heightBytes.AppendElement(mHeightAligned[i]);
+    format.AppendElement(mDrmFormats[i]);
+    fds.AppendElement(ipc::FileDescriptor(mDmabufFds[i]));
+    strides.AppendElement(mStrides[i]);
+    offsets.AppendElement(mOffsets[i]);
+    modifiers.AppendElement(mBufferModifiers[i]);
+  }
+
+  CloseFileDescriptors(lockFD);
+
+  if (mSync) {
+    fenceFDs.AppendElement(ipc::FileDescriptor(mSyncFd));
+  }
+
+  if (mGlobalRefCountFd) {
+    refCountFDs.AppendElement(ipc::FileDescriptor(GlobalRefCountExport()));
+  }
+
+  aOutDescriptor = SurfaceDescriptorDMABuf(
+      mSurfaceType, modifiers, 0, fds, width, height, widthBytes, heightBytes,
+      format, strides, offsets, GetYUVColorSpace(), mColorRange, fenceFDs, mUID,
+      refCountFDs);
+  return true;
+}
+
+bool DMABufSurfaceYUV::CreateEGLImage(GLContext* aGLContext, int aPlane) {
+  LOGDMABUF(
+      ("DMABufSurfaceYUV::CreateEGLImage() UID %d plane %d", mUID, aPlane));
+  MOZ_ASSERT(mEGLImage[aPlane] == LOCAL_EGL_NO_IMAGE,
+             "EGLImage is already created!");
+  MOZ_ASSERT(aGLContext, "Missing GLContext!");
+
+  const auto& gle = gl::GLContextEGL::Cast(aGLContext);
+  const auto& egl = gle->mEgl;
+
+  MutexAutoLock lockFD(mSurfaceLock);
+  if (!OpenFileDescriptorForPlane(lockFD, aPlane)) {
+    LOGDMABUF(("  failed to open dmabuf file descriptors"));
+    return false;
+  }
+
+  nsTArray<EGLint> attribs;
+  attribs.AppendElement(LOCAL_EGL_WIDTH);
+  attribs.AppendElement(mWidthAligned[aPlane]);
+  attribs.AppendElement(LOCAL_EGL_HEIGHT);
+  attribs.AppendElement(mHeightAligned[aPlane]);
+  attribs.AppendElement(LOCAL_EGL_LINUX_DRM_FOURCC_EXT);
+  attribs.AppendElement(mDrmFormats[aPlane]);
+#define ADD_PLANE_ATTRIBS_NV12(plane_idx)                                 \
+  attribs.AppendElement(LOCAL_EGL_DMA_BUF_PLANE##plane_idx##_FD_EXT);     \
+  attribs.AppendElement(mDmabufFds[aPlane]);                              \
+  attribs.AppendElement(LOCAL_EGL_DMA_BUF_PLANE##plane_idx##_OFFSET_EXT); \
+  attribs.AppendElement((int)mOffsets[aPlane]);                           \
+  attribs.AppendElement(LOCAL_EGL_DMA_BUF_PLANE##plane_idx##_PITCH_EXT);  \
+  attribs.AppendElement((int)mStrides[aPlane]);                           \
+  if (mBufferModifiers[aPlane] != DRM_FORMAT_MOD_INVALID) {               \
+    attribs.AppendElement(                                                \
+        LOCAL_EGL_DMA_BUF_PLANE##plane_idx##_MODIFIER_LO_EXT);            \
+    attribs.AppendElement(mBufferModifiers[aPlane] & 0xFFFFFFFF);         \
+    attribs.AppendElement(                                                \
+        LOCAL_EGL_DMA_BUF_PLANE##plane_idx##_MODIFIER_HI_EXT);            \
+    attribs.AppendElement(mBufferModifiers[aPlane] >> 32);                \
+  }
+  ADD_PLANE_ATTRIBS_NV12(0);
+#undef ADD_PLANE_ATTRIBS_NV12
+  attribs.AppendElement(LOCAL_EGL_NONE);
+
+  mEGLImage[aPlane] =
+      egl->fCreateImage(LOCAL_EGL_NO_CONTEXT, LOCAL_EGL_LINUX_DMA_BUF_EXT,
+                        nullptr, attribs.Elements());
+
+  CloseFileDescriptorForPlane(lockFD, aPlane);
+
+  if (mEGLImage[aPlane] == LOCAL_EGL_NO_IMAGE) {
+    LOGDMABUF(("  EGLImageKHR creation failed"));
+    return false;
+  }
+
+  LOGDMABUF(("  Success."));
+  return true;
+}
+
+void DMABufSurfaceYUV::ReleaseEGLImages(GLContext* aGLContext) {
+  LOGDMABUF(("DMABufSurfaceYUV::ReleaseEGLImages() UID %d", mUID));
+  MOZ_ASSERT(aGLContext, "Missing GLContext!");
+
+  const auto& gle = gl::GLContextEGL::Cast(aGLContext);
+  const auto& egl = gle->mEgl;
+
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    if (mEGLImage[i] != LOCAL_EGL_NO_IMAGE) {
+      egl->fDestroyImage(mEGLImage[i]);
+      mEGLImage[i] = LOCAL_EGL_NO_IMAGE;
+    }
+  }
+}
+
+bool DMABufSurfaceYUV::CreateTexture(GLContext* aGLContext, int aPlane) {
+  LOGDMABUF(
+      ("DMABufSurfaceYUV::CreateTexture() UID %d plane %d", mUID, aPlane));
+  MOZ_ASSERT(!mTexture[aPlane], "Texture is already created!");
+  MOZ_ASSERT(aGLContext, "Missing GLContext!");
+
+  if (!aGLContext->MakeCurrent()) {
+    LOGDMABUF(("  Failed to make GL context current."));
+    return false;
+  }
+  if (!CreateEGLImage(aGLContext, aPlane)) {
+    return false;
+  }
+  aGLContext->fGenTextures(1, &mTexture[aPlane]);
+  const ScopedBindTexture savedTex(aGLContext, mTexture[aPlane]);
+  aGLContext->fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_WRAP_S,
+                             LOCAL_GL_CLAMP_TO_EDGE);
+  aGLContext->fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_WRAP_T,
+                             LOCAL_GL_CLAMP_TO_EDGE);
+  aGLContext->fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_MAG_FILTER,
+                             LOCAL_GL_LINEAR);
+  aGLContext->fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_MIN_FILTER,
+                             LOCAL_GL_LINEAR);
+  aGLContext->fEGLImageTargetTexture2D(LOCAL_GL_TEXTURE_2D, mEGLImage[aPlane]);
+  mGL = aGLContext;
+  return true;
+}
+
+void DMABufSurfaceYUV::ReleaseTextures() {
+  LOGDMABUF(("DMABufSurfaceYUV::ReleaseTextures() UID %d", mUID));
+
+  FenceDelete();
+
+  bool textureActive = false;
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    if (mTexture[i] || mEGLImage[i]) {
+      textureActive = true;
+      break;
+    }
+  }
+
+  if (!textureActive) {
+    return;
+  }
+
+  if (!mGL) {
+#ifdef NIGHTLY_BUILD
+    MOZ_DIAGNOSTIC_ASSERT(mGL, "Missing GL context!");
+#else
+    NS_WARNING(
+        "DMABufSurfaceYUV::ReleaseTextures(): Missing GL context! We're "
+        "leaking textures!");
+    return;
+#endif
+  }
+
+  if (!mGL->MakeCurrent()) {
+    NS_WARNING(
+        "DMABufSurfaceYUV::ReleaseTextures(): MakeCurrent failed. We're "
+        "leaking textures!");
+    return;
+  }
+
+  mGL->fDeleteTextures(DMABUF_BUFFER_PLANES, mTexture);
+  for (int i = 0; i < DMABUF_BUFFER_PLANES; i++) {
+    mTexture[i] = 0;
+  }
+  ReleaseEGLImages(mGL);
+  mGL = nullptr;
+}
+
+bool DMABufSurfaceYUV::VerifyTextureCreation() {
+  LOGDMABUF(("DMABufSurfaceYUV::VerifyTextureCreation() UID %d", mUID));
+
+  StaticMutexAutoLock lock(sSnapshotContextMutex);
+  RefPtr<GLContext> context = ClaimSnapshotGLContext();
+  auto release = MakeScopeExit([&] {
+    ReleaseEGLImages(context);
+    ReturnSnapshotGLContext(context);
+  });
+
+  for (int i = 0; i < mBufferPlaneCount; i++) {
+    if (!CreateEGLImage(context, i)) {
+      LOGDMABUF(("  failed to create EGL image!"));
+      return false;
+    }
+  }
+
+  LOGDMABUF(("  success"));
+  return true;
+}
+
+gfx::SurfaceFormat DMABufSurfaceYUV::GetFormat() {
+  switch (mSurfaceType) {
+    case SURFACE_NV12:
+      return gfx::SurfaceFormat::NV12;
+    case SURFACE_YUV420:
+      return gfx::SurfaceFormat::YUV;
+    default:
+      NS_WARNING("DMABufSurfaceYUV::GetFormat(): Wrong surface format!");
+      return gfx::SurfaceFormat::UNKNOWN;
+  }
+}
+
+// GL uses swapped R and B components so report accordingly.
+gfx::SurfaceFormat DMABufSurfaceYUV::GetFormatGL() { return GetFormat(); }
+
+int DMABufSurfaceYUV::GetTextureCount() {
+  switch (mSurfaceType) {
+    case SURFACE_NV12:
+      return 2;
+    case SURFACE_YUV420:
+      return 3;
+    default:
+      NS_WARNING("DMABufSurfaceYUV::GetTextureCount(): Wrong surface format!");
+      return 1;
+  }
+}
+
+void DMABufSurfaceYUV::ReleaseSurface() {
+  LOGDMABUF(("DMABufSurfaceYUV::ReleaseSurface() UID %d", mUID));
+  ReleaseTextures();
+  ReleaseDMABuf();
+}
+
+nsresult DMABufSurfaceYUV::ReadIntoBuffer(uint8_t* aData, int32_t aStride,
+                                          const gfx::IntSize& aSize,
+                                          gfx::SurfaceFormat aFormat) {
+  LOGDMABUF(("DMABufSurfaceYUV::ReadIntoBuffer UID %d", mUID));
+
+  MOZ_ASSERT(aSize.width == GetWidth());
+  MOZ_ASSERT(aSize.height == GetHeight());
+
+  StaticMutexAutoLock lock(sSnapshotContextMutex);
+  RefPtr<GLContext> context = ClaimSnapshotGLContext();
+  auto releaseTextures = mozilla::MakeScopeExit([&] {
+    ReleaseTextures();
+    ReturnSnapshotGLContext(context);
+  });
+
+  for (int i = 0; i < GetTextureCount(); i++) {
+    if (!GetTexture(i) && !CreateTexture(context, i)) {
+      LOGDMABUF(("ReadIntoBuffer: Failed to create DMABuf textures."));
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  ScopedTexture scopedTex(context);
+  ScopedBindTexture boundTex(context, scopedTex.Texture());
+
+  context->fTexImage2D(LOCAL_GL_TEXTURE_2D, 0, LOCAL_GL_RGBA, aSize.width,
+                       aSize.height, 0, LOCAL_GL_RGBA, LOCAL_GL_UNSIGNED_BYTE,
+                       nullptr);
+
+  ScopedFramebufferForTexture autoFBForTex(context, scopedTex.Texture());
+  if (!autoFBForTex.IsComplete()) {
+    LOGDMABUF(("ReadIntoBuffer: ScopedFramebufferForTexture failed."));
+    return NS_ERROR_FAILURE;
+  }
+
+  const gl::OriginPos destOrigin = gl::OriginPos::BottomLeft;
+  {
+    const ScopedBindFramebuffer bindFB(context, autoFBForTex.FB());
+    if (!context->BlitHelper()->Blit(this, aSize, destOrigin)) {
+      LOGDMABUF(("ReadIntoBuffer: Blit failed."));
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  ScopedBindFramebuffer bind(context, autoFBForTex.FB());
+  ReadPixelsIntoBuffer(context, aData, aStride, aSize, aFormat);
+  return NS_OK;
+}
+
+already_AddRefed<gfx::DataSourceSurface>
+DMABufSurfaceYUV::GetAsSourceSurface() {
+  LOGDMABUF(("DMABufSurfaceYUV::GetAsSourceSurface UID %d", mUID));
+
+  gfx::IntSize size(GetWidth(), GetHeight());
+  const auto format = gfx::SurfaceFormat::B8G8R8A8;
+  RefPtr<gfx::DataSourceSurface> source =
+      gfx::Factory::CreateDataSourceSurface(size, format);
+  if (NS_WARN_IF(!source)) {
+    LOGDMABUF(("GetAsSourceSurface: CreateDataSourceSurface failed."));
+    return nullptr;
+  }
+
+  gfx::DataSourceSurface::ScopedMap map(source,
+                                        gfx::DataSourceSurface::READ_WRITE);
+  if (NS_WARN_IF(!map.IsMapped())) {
+    LOGDMABUF(("GetAsSourceSurface: Mapping surface failed."));
+    return nullptr;
+  }
+
+  if (NS_WARN_IF(NS_FAILED(
+          ReadIntoBuffer(map.GetData(), map.GetStride(), size, format)))) {
+    LOGDMABUF(("GetAsSourceSurface: Reading into buffer failed."));
+    return nullptr;
+  }
+
+  return source.forget();
+}
+
+nsresult DMABufSurfaceYUV::BuildSurfaceDescriptorBuffer(
+    SurfaceDescriptorBuffer& aSdBuffer, Image::BuildSdbFlags aFlags,
+    const std::function<MemoryOrShmem(uint32_t)>& aAllocate) {
+  LOGDMABUF(("DMABufSurfaceYUV::BuildSurfaceDescriptorBuffer UID %d", mUID));
+
+  gfx::IntSize size(GetWidth(), GetHeight());
+  const auto format = gfx::SurfaceFormat::B8G8R8A8;
+
+  uint8_t* buffer = nullptr;
+  int32_t stride = 0;
+  nsresult rv = Image::AllocateSurfaceDescriptorBufferRgb(
+      size, format, buffer, aSdBuffer, stride, aAllocate);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    LOGDMABUF(("BuildSurfaceDescriptorBuffer allocate descriptor failed"));
+    return rv;
+  }
+
+  return ReadIntoBuffer(buffer, stride, size, format);
+}
+
+#if 0
+void DMABufSurfaceYUV::ClearPlane(int aPlane) {
+  if (!MapInternal(0, 0, mWidth[aPlane], mHeight[aPlane], nullptr,
+                   GBM_BO_TRANSFER_WRITE, aPlane)) {
+    return;
+  }
+  if ((int)mMappedRegionStride[aPlane] < mWidth[aPlane]) {
+    return;
+  }
+  memset((char*)mMappedRegion[aPlane], 0,
+         mMappedRegionStride[aPlane] * mHeight[aPlane]);
+  Unmap(aPlane);
+}
+
+#  include "gfxUtils.h"
+
+void DMABufSurfaceYUV::DumpToFile(const char* aFile) {
+  RefPtr<gfx::DataSourceSurface> surf = GetAsSourceSurface();
+  gfxUtils::WriteAsPNG(surf, aFile);
+}
+#endif
diff --git a/widget/gtk/DMABufSurface.h b/widget/gtk/DMABufSurface.h
new file mode 100644
index 0000000000..9bb8928cca
--- /dev/null
+++ b/widget/gtk/DMABufSurface.h
@@ -0,0 +1,413 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DMABufSurface_h__
+#define DMABufSurface_h__
+
+#include <functional>
+#include <stdint.h>
+#include "mozilla/widget/va_drmcommon.h"
+#include "GLTypes.h"
+#include "ImageContainer.h"
+#include "nsISupportsImpl.h"
+#include "mozilla/gfx/Types.h"
+#include "mozilla/Mutex.h"
+
+typedef void* EGLImageKHR;
+typedef void* EGLSyncKHR;
+
+#define DMABUF_BUFFER_PLANES 4
+
+#ifndef VA_FOURCC_NV12
+#  define VA_FOURCC_NV12 0x3231564E
+#endif
+#ifndef VA_FOURCC_YV12
+#  define VA_FOURCC_YV12 0x32315659
+#endif
+#ifndef VA_FOURCC_P010
+#  define VA_FOURCC_P010 0x30313050
+#endif
+
+namespace mozilla {
+namespace gfx {
+class DataSourceSurface;
+}
+namespace layers {
+class MemoryOrShmem;
+class SurfaceDescriptor;
+class SurfaceDescriptorBuffer;
+class SurfaceDescriptorDMABuf;
+}  // namespace layers
+namespace gl {
+class GLContext;
+}
+}  // namespace mozilla
+
+typedef enum {
+  // Use alpha pixel format
+  DMABUF_ALPHA = 1 << 0,
+  // Surface is used as texture and may be also shared
+  DMABUF_TEXTURE = 1 << 1,
+  // Use modifiers. Such dmabuf surface may have more planes
+  // and complex internal structure (tiling/compression/etc.)
+  // so we can't do direct rendering to it.
+  DMABUF_USE_MODIFIERS = 1 << 3,
+} DMABufSurfaceFlags;
+
+class DMABufSurfaceRGBA;
+class DMABufSurfaceYUV;
+struct wl_buffer;
+
+namespace mozilla::widget {
+struct GbmFormat;
+}
+
+class DMABufSurface {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(DMABufSurface)
+
+  enum SurfaceType {
+    SURFACE_RGBA,
+    SURFACE_NV12,
+    SURFACE_YUV420,
+  };
+
+  // Import surface from SurfaceDescriptor. This is usually
+  // used to copy surface from another process over IPC.
+  // When a global reference counter was created for the surface
+  // (see bellow) it's automatically referenced.
+  static already_AddRefed<DMABufSurface> CreateDMABufSurface(
+      const mozilla::layers::SurfaceDescriptor& aDesc);
+
+  // Export surface to another process via. SurfaceDescriptor.
+  virtual bool Serialize(
+      mozilla::layers::SurfaceDescriptor& aOutDescriptor) = 0;
+
+  virtual int GetWidth(int aPlane = 0) = 0;
+  virtual int GetHeight(int aPlane = 0) = 0;
+  virtual mozilla::gfx::SurfaceFormat GetFormat() = 0;
+  virtual mozilla::gfx::SurfaceFormat GetFormatGL() = 0;
+
+  virtual bool CreateTexture(mozilla::gl::GLContext* aGLContext,
+                             int aPlane = 0) = 0;
+  virtual void ReleaseTextures() = 0;
+  virtual GLuint GetTexture(int aPlane = 0) = 0;
+  virtual EGLImageKHR GetEGLImage(int aPlane = 0) = 0;
+
+  SurfaceType GetSurfaceType() { return mSurfaceType; };
+  virtual int GetTextureCount() = 0;
+
+  bool IsMapped(int aPlane = 0) { return (mMappedRegion[aPlane] != nullptr); };
+  void Unmap(int aPlane = 0);
+
+  virtual DMABufSurfaceRGBA* GetAsDMABufSurfaceRGBA() { return nullptr; }
+  virtual DMABufSurfaceYUV* GetAsDMABufSurfaceYUV() { return nullptr; }
+  virtual already_AddRefed<mozilla::gfx::DataSourceSurface>
+  GetAsSourceSurface() {
+    return nullptr;
+  }
+
+  virtual nsresult BuildSurfaceDescriptorBuffer(
+      mozilla::layers::SurfaceDescriptorBuffer& aSdBuffer,
+      mozilla::layers::Image::BuildSdbFlags aFlags,
+      const std::function<mozilla::layers::MemoryOrShmem(uint32_t)>& aAllocate);
+
+  virtual mozilla::gfx::YUVColorSpace GetYUVColorSpace() {
+    return mozilla::gfx::YUVColorSpace::Default;
+  };
+
+  bool IsFullRange() { return mColorRange == mozilla::gfx::ColorRange::FULL; };
+  void SetColorRange(mozilla::gfx::ColorRange aColorRange) {
+    mColorRange = aColorRange;
+  };
+
+  void FenceSet();
+  void FenceWait();
+  void FenceDelete();
+
+  // Set and get a global surface UID. The UID is shared across process
+  // and it's used to track surface lifetime in various parts of rendering
+  // engine.
+  uint32_t GetUID() const { return mUID; };
+
+  // Creates a global reference counter objects attached to the surface.
+  // It's created as unreferenced, i.e. IsGlobalRefSet() returns false
+  // right after GlobalRefCountCreate() call.
+  //
+  // The counter is shared by all surface instances across processes
+  // so it tracks global surface usage.
+  //
+  // The counter is automatically referenced when a new surface instance is
+  // created with SurfaceDescriptor (usually copied to another process over IPC)
+  // and it's unreferenced when surface is deleted.
+  //
+  // So without any additional GlobalRefAdd()/GlobalRefRelease() calls
+  // the IsGlobalRefSet() returns true if any other process use the surface.
+  void GlobalRefCountCreate();
+  void GlobalRefCountDelete();
+
+  // If global reference counter was created by GlobalRefCountCreate()
+  // returns true when there's an active surface reference.
+  bool IsGlobalRefSet() const;
+
+  // Add/Remove additional reference to the surface global reference counter.
+  void GlobalRefAdd();
+  void GlobalRefRelease();
+
+  // Release all underlying data.
+  virtual void ReleaseSurface() = 0;
+
+#ifdef DEBUG
+  virtual void DumpToFile(const char* pFile){};
+#endif
+
+  DMABufSurface(SurfaceType aSurfaceType);
+
+ protected:
+  virtual bool Create(const mozilla::layers::SurfaceDescriptor& aDesc) = 0;
+
+  // Import global ref count object from IPC by file descriptor.
+  // This adds global ref count reference to the surface.
+  void GlobalRefCountImport(int aFd);
+  // Export global ref count object by file descriptor.
+  int GlobalRefCountExport();
+
+  void ReleaseDMABuf();
+
+  void* MapInternal(uint32_t aX, uint32_t aY, uint32_t aWidth, uint32_t aHeight,
+                    uint32_t* aStride, int aGbmFlags, int aPlane = 0);
+
+  // We want to keep number of opened file descriptors low so open/close
+  // DMABuf file handles only when we need them, i.e. when DMABuf is exported
+  // to another process or to EGL.
+  virtual bool OpenFileDescriptorForPlane(
+      const mozilla::MutexAutoLock& aProofOfLock, int aPlane) = 0;
+  virtual void CloseFileDescriptorForPlane(
+      const mozilla::MutexAutoLock& aProofOfLock, int aPlane,
+      bool aForceClose = false) = 0;
+  bool OpenFileDescriptors(const mozilla::MutexAutoLock& aProofOfLock);
+  void CloseFileDescriptors(const mozilla::MutexAutoLock& aProofOfLock,
+                            bool aForceClose = false);
+
+  virtual ~DMABufSurface();
+
+  SurfaceType mSurfaceType;
+  uint64_t mBufferModifiers[DMABUF_BUFFER_PLANES];
+
+  int mBufferPlaneCount;
+  int mDmabufFds[DMABUF_BUFFER_PLANES];
+  int32_t mDrmFormats[DMABUF_BUFFER_PLANES];
+  int32_t mStrides[DMABUF_BUFFER_PLANES];
+  int32_t mOffsets[DMABUF_BUFFER_PLANES];
+
+  struct gbm_bo* mGbmBufferObject[DMABUF_BUFFER_PLANES];
+  void* mMappedRegion[DMABUF_BUFFER_PLANES];
+  void* mMappedRegionData[DMABUF_BUFFER_PLANES];
+  uint32_t mMappedRegionStride[DMABUF_BUFFER_PLANES];
+
+  int mSyncFd;
+  EGLSyncKHR mSync;
+  RefPtr<mozilla::gl::GLContext> mGL;
+
+  int mGlobalRefCountFd;
+  uint32_t mUID;
+  mozilla::Mutex mSurfaceLock MOZ_UNANNOTATED;
+
+  mozilla::gfx::ColorRange mColorRange = mozilla::gfx::ColorRange::LIMITED;
+};
+
+class DMABufSurfaceRGBA final : public DMABufSurface {
+ public:
+  static already_AddRefed<DMABufSurfaceRGBA> CreateDMABufSurface(
+      int aWidth, int aHeight, int aDMABufSurfaceFlags);
+
+  static already_AddRefed<DMABufSurface> CreateDMABufSurface(
+      mozilla::gl::GLContext* aGLContext, const EGLImageKHR aEGLImage,
+      int aWidth, int aHeight);
+
+  bool Serialize(mozilla::layers::SurfaceDescriptor& aOutDescriptor) override;
+
+  DMABufSurfaceRGBA* GetAsDMABufSurfaceRGBA() override { return this; }
+
+  void Clear();
+
+  void ReleaseSurface() override;
+
+  bool CopyFrom(class DMABufSurface* aSourceSurface);
+
+  int GetWidth(int aPlane = 0) override { return mWidth; };
+  int GetHeight(int aPlane = 0) override { return mHeight; };
+  mozilla::gfx::SurfaceFormat GetFormat() override;
+  mozilla::gfx::SurfaceFormat GetFormatGL() override;
+  bool HasAlpha();
+
+  void* MapReadOnly(uint32_t aX, uint32_t aY, uint32_t aWidth, uint32_t aHeight,
+                    uint32_t* aStride = nullptr);
+  void* MapReadOnly(uint32_t* aStride = nullptr);
+  void* Map(uint32_t aX, uint32_t aY, uint32_t aWidth, uint32_t aHeight,
+            uint32_t* aStride = nullptr);
+  void* Map(uint32_t* aStride = nullptr);
+  void* GetMappedRegion(int aPlane = 0) { return mMappedRegion[aPlane]; };
+  uint32_t GetMappedRegionStride(int aPlane = 0) {
+    return mMappedRegionStride[aPlane];
+  };
+
+  bool CreateTexture(mozilla::gl::GLContext* aGLContext,
+                     int aPlane = 0) override;
+  void ReleaseTextures() override;
+  GLuint GetTexture(int aPlane = 0) override { return mTexture; };
+  EGLImageKHR GetEGLImage(int aPlane = 0) override { return mEGLImage; };
+
+#ifdef MOZ_WAYLAND
+  bool CreateWlBuffer();
+  void ReleaseWlBuffer();
+  wl_buffer* GetWlBuffer() { return mWlBuffer; };
+#endif
+
+  int GetTextureCount() override { return 1; };
+
+#ifdef DEBUG
+  void DumpToFile(const char* pFile) override;
+#endif
+
+  DMABufSurfaceRGBA();
+
+ private:
+  DMABufSurfaceRGBA(const DMABufSurfaceRGBA&) = delete;
+  DMABufSurfaceRGBA& operator=(const DMABufSurfaceRGBA&) = delete;
+  ~DMABufSurfaceRGBA();
+
+  bool Create(int aWidth, int aHeight, int aDMABufSurfaceFlags);
+  bool Create(const mozilla::layers::SurfaceDescriptor& aDesc) override;
+  bool Create(mozilla::gl::GLContext* aGLContext, const EGLImageKHR aEGLImage,
+              int aWidth, int aHeight);
+
+  bool ImportSurfaceDescriptor(const mozilla::layers::SurfaceDescriptor& aDesc);
+
+  bool OpenFileDescriptorForPlane(const mozilla::MutexAutoLock& aProofOfLock,
+                                  int aPlane) override;
+  void CloseFileDescriptorForPlane(const mozilla::MutexAutoLock& aProofOfLock,
+                                   int aPlane, bool aForceClose) override;
+
+ private:
+  int mSurfaceFlags;
+
+  int mWidth;
+  int mHeight;
+  mozilla::widget::GbmFormat* mGmbFormat;
+
+  EGLImageKHR mEGLImage;
+  GLuint mTexture;
+  uint32_t mGbmBufferFlags;
+#ifdef MOZ_WAYLAND
+  wl_buffer* mWlBuffer = nullptr;
+#endif
+};
+
+class DMABufSurfaceYUV final : public DMABufSurface {
+ public:
+  static already_AddRefed<DMABufSurfaceYUV> CreateYUVSurface(
+      int aWidth, int aHeight, void** aPixelData = nullptr,
+      int* aLineSizes = nullptr);
+  static already_AddRefed<DMABufSurfaceYUV> CreateYUVSurface(
+      const VADRMPRIMESurfaceDescriptor& aDesc, int aWidth, int aHeight);
+  static already_AddRefed<DMABufSurfaceYUV> CopyYUVSurface(
+      const VADRMPRIMESurfaceDescriptor& aVaDesc, int aWidth, int aHeight);
+  static void ReleaseVADRMPRIMESurfaceDescriptor(
+      VADRMPRIMESurfaceDescriptor& aDesc);
+
+  bool Serialize(mozilla::layers::SurfaceDescriptor& aOutDescriptor) override;
+
+  DMABufSurfaceYUV* GetAsDMABufSurfaceYUV() override { return this; };
+  already_AddRefed<mozilla::gfx::DataSourceSurface> GetAsSourceSurface()
+      override;
+
+  nsresult BuildSurfaceDescriptorBuffer(
+      mozilla::layers::SurfaceDescriptorBuffer& aSdBuffer,
+      mozilla::layers::Image::BuildSdbFlags aFlags,
+      const std::function<mozilla::layers::MemoryOrShmem(uint32_t)>& aAllocate)
+      override;
+
+  int GetWidth(int aPlane = 0) override { return mWidth[aPlane]; }
+  int GetHeight(int aPlane = 0) override { return mHeight[aPlane]; }
+  mozilla::gfx::SurfaceFormat GetFormat() override;
+  mozilla::gfx::SurfaceFormat GetFormatGL() override;
+
+  bool CreateTexture(mozilla::gl::GLContext* aGLContext,
+                     int aPlane = 0) override;
+  void ReleaseTextures() override;
+
+  void ReleaseSurface() override;
+
+  GLuint GetTexture(int aPlane = 0) override { return mTexture[aPlane]; };
+  EGLImageKHR GetEGLImage(int aPlane = 0) override {
+    return mEGLImage[aPlane];
+  };
+
+  int GetTextureCount() override;
+
+  void SetYUVColorSpace(mozilla::gfx::YUVColorSpace aColorSpace) {
+    mColorSpace = aColorSpace;
+  }
+  mozilla::gfx::YUVColorSpace GetYUVColorSpace() override {
+    return mColorSpace;
+  }
+
+  DMABufSurfaceYUV();
+
+  bool UpdateYUVData(void** aPixelData, int* aLineSizes);
+  bool UpdateYUVData(const VADRMPRIMESurfaceDescriptor& aDesc, int aWidth,
+                     int aHeight, bool aCopy);
+  bool VerifyTextureCreation();
+
+ private:
+  DMABufSurfaceYUV(const DMABufSurfaceYUV&) = delete;
+  DMABufSurfaceYUV& operator=(const DMABufSurfaceYUV&) = delete;
+  ~DMABufSurfaceYUV();
+
+  bool Create(const mozilla::layers::SurfaceDescriptor& aDesc) override;
+  bool Create(int aWidth, int aHeight, void** aPixelData, int* aLineSizes);
+  bool CreateYUVPlane(int aPlane);
+  bool CreateLinearYUVPlane(int aPlane, int aWidth, int aHeight,
+                            int aDrmFormat);
+  void UpdateYUVPlane(int aPlane, void* aPixelData, int aLineSize);
+
+  bool MoveYUVDataImpl(const VADRMPRIMESurfaceDescriptor& aDesc, int aWidth,
+                       int aHeight);
+  bool CopyYUVDataImpl(const VADRMPRIMESurfaceDescriptor& aDesc, int aWidth,
+                       int aHeight);
+
+  bool ImportPRIMESurfaceDescriptor(const VADRMPRIMESurfaceDescriptor& aDesc,
+                                    int aWidth, int aHeight);
+  bool ImportSurfaceDescriptor(
+      const mozilla::layers::SurfaceDescriptorDMABuf& aDesc);
+
+  bool OpenFileDescriptorForPlane(const mozilla::MutexAutoLock& aProofOfLock,
+                                  int aPlane) override;
+  void CloseFileDescriptorForPlane(const mozilla::MutexAutoLock& aProofOfLock,
+                                   int aPlane, bool aForceClose) override;
+
+  bool CreateEGLImage(mozilla::gl::GLContext* aGLContext, int aPlane);
+  void ReleaseEGLImages(mozilla::gl::GLContext* aGLContext);
+
+  nsresult ReadIntoBuffer(uint8_t* aData, int32_t aStride,
+                          const mozilla::gfx::IntSize& aSize,
+                          mozilla::gfx::SurfaceFormat aFormat);
+
+  int mWidth[DMABUF_BUFFER_PLANES];
+  int mHeight[DMABUF_BUFFER_PLANES];
+  // Aligned size of the surface imported from VADRMPRIMESurfaceDescriptor.
+  // It's used only internally to create EGLImage as some GL drivers
+  // needs that (Bug 1724385).
+  int mWidthAligned[DMABUF_BUFFER_PLANES];
+  int mHeightAligned[DMABUF_BUFFER_PLANES];
+  EGLImageKHR mEGLImage[DMABUF_BUFFER_PLANES];
+  GLuint mTexture[DMABUF_BUFFER_PLANES];
+  mozilla::gfx::YUVColorSpace mColorSpace =
+      mozilla::gfx::YUVColorSpace::Default;
+};
+
+#endif
diff --git a/widget/gtk/GRefPtr.h b/widget/gtk/GRefPtr.h
new file mode 100644
index 0000000000..1970008811
--- /dev/null
+++ b/widget/gtk/GRefPtr.h
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GRefPtr_h_
+#define GRefPtr_h_
+
+// Allows to use RefPtr<T> with various kinds of GObjects
+
+#include <gdk/gdk.h>
+#include <gio/gio.h>
+#include <gtk/gtk.h>
+#include "mozilla/RefPtr.h"
+
+namespace mozilla {
+
+template <typename T>
+struct GObjectRefPtrTraits {
+  static void AddRef(T* aObject) { g_object_ref(aObject); }
+  static void Release(T* aObject) { g_object_unref(aObject); }
+};
+
+#define GOBJECT_TRAITS(type_) \
+  template <>                 \
+  struct RefPtrTraits<type_> : public GObjectRefPtrTraits<type_> {};
+
+GOBJECT_TRAITS(GtkWidget)
+GOBJECT_TRAITS(GFile)
+GOBJECT_TRAITS(GFileMonitor)
+GOBJECT_TRAITS(GMenu)
+GOBJECT_TRAITS(GMenuItem)
+GOBJECT_TRAITS(GSimpleAction)
+GOBJECT_TRAITS(GSimpleActionGroup)
+GOBJECT_TRAITS(GDBusProxy)
+GOBJECT_TRAITS(GAppInfo)
+GOBJECT_TRAITS(GAppLaunchContext)
+GOBJECT_TRAITS(GdkDragContext)
+GOBJECT_TRAITS(GDBusMessage)
+GOBJECT_TRAITS(GdkPixbuf)
+GOBJECT_TRAITS(GCancellable)
+GOBJECT_TRAITS(GtkIMContext)
+GOBJECT_TRAITS(GUnixFDList)
+GOBJECT_TRAITS(GtkCssProvider)
+GOBJECT_TRAITS(GDBusMethodInvocation)
+
+#undef GOBJECT_TRAITS
+
+template <>
+struct RefPtrTraits<GVariant> {
+  static void AddRef(GVariant* aVariant) { g_variant_ref(aVariant); }
+  static void Release(GVariant* aVariant) { g_variant_unref(aVariant); }
+};
+
+template <>
+struct RefPtrTraits<GHashTable> {
+  static void AddRef(GHashTable* aObject) { g_hash_table_ref(aObject); }
+  static void Release(GHashTable* aObject) { g_hash_table_unref(aObject); }
+};
+
+template <>
+struct RefPtrTraits<GDBusNodeInfo> {
+  static void AddRef(GDBusNodeInfo* aObject) { g_dbus_node_info_ref(aObject); }
+  static void Release(GDBusNodeInfo* aObject) {
+    g_dbus_node_info_unref(aObject);
+  }
+};
+
+}  // namespace mozilla
+
+#endif
diff --git a/widget/gtk/GUniquePtr.h b/widget/gtk/GUniquePtr.h
new file mode 100644
index 0000000000..0d164f9369
--- /dev/null
+++ b/widget/gtk/GUniquePtr.h
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GUniquePtr_h_
+#define GUniquePtr_h_
+
+// Provides GUniquePtr to g_free a given pointer.
+
+#include <glib.h>
+#include <gtk/gtk.h>
+#include "mozilla/UniquePtr.h"
+
+namespace mozilla {
+
+struct GFreeDeleter {
+  constexpr GFreeDeleter() = default;
+  void operator()(GdkEventCrossing* aPtr) const {
+    gdk_event_free((GdkEvent*)aPtr);
+  }
+  void operator()(GdkEventKey* aPtr) const { gdk_event_free((GdkEvent*)aPtr); }
+  void operator()(GdkEvent* aPtr) const { gdk_event_free(aPtr); }
+  void operator()(GError* aPtr) const { g_error_free(aPtr); }
+  void operator()(void* aPtr) const { g_free(aPtr); }
+  void operator()(GtkPaperSize* aPtr) const { gtk_paper_size_free(aPtr); }
+  void operator()(gchar** aPtr) const { g_strfreev(aPtr); }
+};
+
+template <typename T>
+using GUniquePtr = UniquePtr<T, GFreeDeleter>;
+
+}  // namespace mozilla
+
+#endif
diff --git a/widget/gtk/GfxInfo.cpp b/widget/gtk/GfxInfo.cpp
new file mode 100644
index 0000000000..4dadbc81b5
--- /dev/null
+++ b/widget/gtk/GfxInfo.cpp
@@ -0,0 +1,1556 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GfxInfo.h"
+
+#include <cctype>
+#include <errno.h>
+#include <unistd.h>
+#include <string>
+#include <poll.h>
+#include <sys/types.h>
+#include <sys/utsname.h>
+#include <sys/wait.h>
+#include <glib.h>
+#include <fcntl.h>
+
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/SSE.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/XREAppData.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/GUniquePtr.h"
+#include "mozilla/StaticPrefs_media.h"
+#include "nsCRTGlue.h"
+#include "nsExceptionHandler.h"
+#include "nsPrintfCString.h"
+#include "nsString.h"
+#include "nsStringFwd.h"
+#include "nsUnicharUtils.h"
+#include "nsWhitespaceTokenizer.h"
+#include "prenv.h"
+#include "WidgetUtilsGtk.h"
+#include "MediaCodecsSupport.h"
+#include "nsAppRunner.h"
+
+// How long we wait for data from glxtest/vaapi test process in milliseconds.
+#define GFX_TEST_TIMEOUT 4000
+#define VAAPI_TEST_TIMEOUT 2000
+#define V4L2_TEST_TIMEOUT 2000
+
+#define GLX_PROBE_BINARY u"glxtest"_ns
+#define VAAPI_PROBE_BINARY u"vaapitest"_ns
+#define V4L2_PROBE_BINARY u"v4l2test"_ns
+
+namespace mozilla::widget {
+
+#ifdef DEBUG
+NS_IMPL_ISUPPORTS_INHERITED(GfxInfo, GfxInfoBase, nsIGfxInfoDebug)
+#endif
+
+int GfxInfo::sGLXTestPipe = -1;
+pid_t GfxInfo::sGLXTestPID = 0;
+
+// bits to use decoding codec information returned from glxtest
+constexpr int CODEC_HW_H264 = 1 << 4;
+constexpr int CODEC_HW_VP8 = 1 << 5;
+constexpr int CODEC_HW_VP9 = 1 << 6;
+constexpr int CODEC_HW_AV1 = 1 << 7;
+
+nsresult GfxInfo::Init() {
+  mGLMajorVersion = 0;
+  mGLMinorVersion = 0;
+  mHasTextureFromPixmap = false;
+  mIsMesa = false;
+  mIsAccelerated = true;
+  mIsWayland = false;
+  mIsXWayland = false;
+  mHasMultipleGPUs = false;
+  mGlxTestError = false;
+  return GfxInfoBase::Init();
+}
+
+void GfxInfo::AddCrashReportAnnotations() {
+  CrashReporter::AnnotateCrashReport(CrashReporter::Annotation::AdapterVendorID,
+                                     mVendorId);
+  CrashReporter::AnnotateCrashReport(CrashReporter::Annotation::AdapterDeviceID,
+                                     mDeviceId);
+  CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::AdapterDriverVendor, mDriverVendor);
+  CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::AdapterDriverVersion, mDriverVersion);
+  CrashReporter::AnnotateCrashReport(CrashReporter::Annotation::IsWayland,
+                                     mIsWayland);
+  CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::DesktopEnvironment,
+      GetDesktopEnvironmentIdentifier());
+
+  if (mHasMultipleGPUs) {
+    nsAutoCString note;
+    note.AppendLiteral("Has dual GPUs.");
+    if (!mSecondaryVendorId.IsEmpty()) {
+      note.AppendLiteral(" GPU #2: AdapterVendorID2: ");
+      note.Append(mSecondaryVendorId);
+      note.AppendLiteral(", AdapterDeviceID2: ");
+      note.Append(mSecondaryDeviceId);
+    }
+    CrashReporter::AppendAppNotesToCrashReport(note);
+  }
+}
+
+static bool MakeFdNonBlocking(int fd) {
+  return fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK) != -1;
+}
+
+static bool ManageChildProcess(const char* aProcessName, int* aPID, int* aPipe,
+                               int aTimeout, char** aData) {
+  // Don't try anything if we failed before
+  if (*aPID < 0) {
+    return false;
+  }
+
+  GIOChannel* channel = nullptr;
+  *aData = nullptr;
+
+  auto free = mozilla::MakeScopeExit([&] {
+    if (channel) {
+      g_io_channel_unref(channel);
+    }
+    if (*aPipe >= 0) {
+      close(*aPipe);
+      *aPipe = -1;
+    }
+  });
+
+  const TimeStamp deadline =
+      TimeStamp::Now() + TimeDuration::FromMilliseconds(aTimeout);
+
+  struct pollfd pfd {};
+  pfd.fd = *aPipe;
+  pfd.events = POLLIN;
+
+  while (poll(&pfd, 1, aTimeout) != 1) {
+    if (errno != EAGAIN && errno != EINTR) {
+      gfxCriticalNote << "ManageChildProcess(" << aProcessName
+                      << "): poll failed: " << strerror(errno) << "\n";
+      return false;
+    }
+    if (TimeStamp::Now() > deadline) {
+      gfxCriticalNote << "ManageChildProcess(" << aProcessName
+                      << "): process hangs\n";
+      return false;
+    }
+  }
+
+  channel = g_io_channel_unix_new(*aPipe);
+  MakeFdNonBlocking(*aPipe);
+
+  GUniquePtr<GError> error;
+  gsize length = 0;
+  int ret;
+  do {
+    error = nullptr;
+    ret = g_io_channel_read_to_end(channel, aData, &length,
+                                   getter_Transfers(error));
+  } while (ret == G_IO_STATUS_AGAIN && TimeStamp::Now() < deadline);
+  if (error || ret != G_IO_STATUS_NORMAL) {
+    gfxCriticalNote << "ManageChildProcess(" << aProcessName
+                    << "): failed to read data from child process: ";
+    if (error) {
+      gfxCriticalNote << error->message;
+    } else {
+      gfxCriticalNote << "timeout";
+    }
+    return false;
+  }
+
+  int status = 0;
+  int pid = *aPID;
+  *aPID = -1;
+
+  while (true) {
+    int ret = waitpid(pid, &status, WNOHANG);
+    if (ret > 0) {
+      break;
+    }
+    if (ret < 0) {
+      if (errno == ECHILD) {
+        // Bug 718629
+        // ECHILD happens when the glxtest process got reaped got reaped after a
+        // PR_CreateProcess as per bug 227246. This shouldn't matter, as we
+        // still seem to get the data from the pipe, and if we didn't, the
+        // outcome would be to blocklist anyway.
+        return true;
+      }
+      if (errno != EAGAIN && errno != EINTR) {
+        gfxCriticalNote << "ManageChildProcess(" << aProcessName
+                        << "): waitpid failed: " << strerror(errno) << "\n";
+        return false;
+      }
+    }
+    if (TimeStamp::Now() > deadline) {
+      gfxCriticalNote << "ManageChildProcess(" << aProcessName
+                      << "): process hangs\n";
+      return false;
+    }
+    // Wait 50ms to another waitpid() check.
+    usleep(50000);
+  }
+
+  return WIFEXITED(status) && WEXITSTATUS(status) == EXIT_SUCCESS;
+}
+
+// to understand this function, see bug 639842. We retrieve the OpenGL driver
+// information in a separate process to protect against bad drivers.
+void GfxInfo::GetData() {
+  if (mInitialized) {
+    return;
+  }
+  mInitialized = true;
+
+  // In some cases (xpcshell test, Profile manager etc.)
+  // FireGLXTestProcess() is not fired in advance
+  // so we call it here.
+  GfxInfo::FireGLXTestProcess();
+
+  GfxInfoBase::GetData();
+
+  char* glxData = nullptr;
+  auto free = mozilla::MakeScopeExit([&] { g_free((void*)glxData); });
+
+  bool error = !ManageChildProcess("glxtest", &sGLXTestPID, &sGLXTestPipe,
+                                   GFX_TEST_TIMEOUT, &glxData);
+  if (error) {
+    gfxCriticalNote << "glxtest: ManageChildProcess failed\n";
+  }
+
+  nsCString glVendor;
+  nsCString glRenderer;
+  nsCString glVersion;
+  nsCString textureFromPixmap;
+  nsCString testType;
+
+  // Available if GLX_MESA_query_renderer is supported.
+  nsCString mesaVendor;
+  nsCString mesaDevice;
+  nsCString mesaAccelerated;
+  // Available if using a DRI-based libGL stack.
+  nsCString driDriver;
+  nsCString adapterRam;
+
+  nsCString drmRenderDevice;
+
+  nsCString ddxDriver;
+
+  AutoTArray<nsCString, 2> pciVendors;
+  AutoTArray<nsCString, 2> pciDevices;
+
+  nsCString* stringToFill = nullptr;
+  bool logString = false;
+  bool errorLog = false;
+
+  char* bufptr = glxData;
+
+  while (true) {
+    char* line = NS_strtok("\n", &bufptr);
+    if (!line) break;
+    if (stringToFill) {
+      stringToFill->Assign(line);
+      stringToFill = nullptr;
+    } else if (logString) {
+      gfxCriticalNote << "glxtest: " << line;
+      logString = false;
+    } else if (!strcmp(line, "VENDOR")) {
+      stringToFill = &glVendor;
+    } else if (!strcmp(line, "RENDERER")) {
+      stringToFill = &glRenderer;
+    } else if (!strcmp(line, "VERSION")) {
+      stringToFill = &glVersion;
+    } else if (!strcmp(line, "TFP")) {
+      stringToFill = &textureFromPixmap;
+    } else if (!strcmp(line, "MESA_VENDOR_ID")) {
+      stringToFill = &mesaVendor;
+    } else if (!strcmp(line, "MESA_DEVICE_ID")) {
+      stringToFill = &mesaDevice;
+    } else if (!strcmp(line, "MESA_ACCELERATED")) {
+      stringToFill = &mesaAccelerated;
+    } else if (!strcmp(line, "MESA_VRAM")) {
+      stringToFill = &adapterRam;
+    } else if (!strcmp(line, "DDX_DRIVER")) {
+      stringToFill = &ddxDriver;
+    } else if (!strcmp(line, "DRI_DRIVER")) {
+      stringToFill = &driDriver;
+    } else if (!strcmp(line, "PCI_VENDOR_ID")) {
+      stringToFill = pciVendors.AppendElement();
+    } else if (!strcmp(line, "PCI_DEVICE_ID")) {
+      stringToFill = pciDevices.AppendElement();
+    } else if (!strcmp(line, "DRM_RENDERDEVICE")) {
+      stringToFill = &drmRenderDevice;
+    } else if (!strcmp(line, "TEST_TYPE")) {
+      stringToFill = &testType;
+    } else if (!strcmp(line, "WARNING")) {
+      logString = true;
+    } else if (!strcmp(line, "ERROR")) {
+      logString = true;
+      errorLog = true;
+    }
+  }
+
+  MOZ_ASSERT(pciDevices.Length() == pciVendors.Length(),
+             "Missing PCI vendors/devices");
+
+  size_t pciLen = std::min(pciVendors.Length(), pciDevices.Length());
+  mHasMultipleGPUs = pciLen > 1;
+
+  if (!strcmp(textureFromPixmap.get(), "TRUE")) mHasTextureFromPixmap = true;
+
+  // only useful for Linux kernel version check for FGLRX driver.
+  // assumes X client == X server, which is sad.
+  struct utsname unameobj {};
+  if (uname(&unameobj) >= 0) {
+    mOS.Assign(unameobj.sysname);
+    mOSRelease.Assign(unameobj.release);
+  }
+
+  const char* spoofedVendor = PR_GetEnv("MOZ_GFX_SPOOF_GL_VENDOR");
+  if (spoofedVendor) glVendor.Assign(spoofedVendor);
+  const char* spoofedRenderer = PR_GetEnv("MOZ_GFX_SPOOF_GL_RENDERER");
+  if (spoofedRenderer) glRenderer.Assign(spoofedRenderer);
+  const char* spoofedVersion = PR_GetEnv("MOZ_GFX_SPOOF_GL_VERSION");
+  if (spoofedVersion) glVersion.Assign(spoofedVersion);
+  const char* spoofedOS = PR_GetEnv("MOZ_GFX_SPOOF_OS");
+  if (spoofedOS) mOS.Assign(spoofedOS);
+  const char* spoofedOSRelease = PR_GetEnv("MOZ_GFX_SPOOF_OS_RELEASE");
+  if (spoofedOSRelease) mOSRelease.Assign(spoofedOSRelease);
+
+  // Scan the GL_VERSION string for the GL and driver versions.
+  nsCWhitespaceTokenizer tokenizer(glVersion);
+  while (tokenizer.hasMoreTokens()) {
+    nsCString token(tokenizer.nextToken());
+    unsigned int major = 0, minor = 0, revision = 0, patch = 0;
+    if (sscanf(token.get(), "%u.%u.%u.%u", &major, &minor, &revision, &patch) >=
+        2) {
+      // A survey of GL_VENDOR strings indicates that the first version is
+      // always the GL version, the second is usually the driver version.
+      if (mGLMajorVersion == 0) {
+        mGLMajorVersion = major;
+        mGLMinorVersion = minor;
+      } else if (mDriverVersion.IsEmpty()) {  // Not already spoofed.
+        mDriverVersion =
+            nsPrintfCString("%u.%u.%u.%u", major, minor, revision, patch);
+      }
+    }
+  }
+
+  if (mGLMajorVersion == 0) {
+    NS_WARNING("Failed to parse GL version!");
+  }
+
+  mDrmRenderDevice = std::move(drmRenderDevice);
+  mTestType = std::move(testType);
+
+  // Mesa always exposes itself in the GL_VERSION string, but not always the
+  // GL_VENDOR string.
+  mIsMesa = glVersion.Find("Mesa") != -1;
+
+  // We need to use custom driver vendor IDs for mesa so we can treat them
+  // differently than the proprietary drivers.
+  if (mIsMesa) {
+    mIsAccelerated = !mesaAccelerated.Equals("FALSE");
+    // Process software rasterizers before the DRI driver string; we may be
+    // forcing software rasterization on a DRI-accelerated X server by using
+    // LIBGL_ALWAYS_SOFTWARE or a similar restriction.
+    if (strcasestr(glRenderer.get(), "llvmpipe")) {
+      CopyUTF16toUTF8(
+          GfxDriverInfo::GetDriverVendor(DriverVendor::MesaLLVMPipe),
+          mDriverVendor);
+      mIsAccelerated = false;
+    } else if (strcasestr(glRenderer.get(), "softpipe")) {
+      CopyUTF16toUTF8(
+          GfxDriverInfo::GetDriverVendor(DriverVendor::MesaSoftPipe),
+          mDriverVendor);
+      mIsAccelerated = false;
+    } else if (strcasestr(glRenderer.get(), "software rasterizer")) {
+      CopyUTF16toUTF8(GfxDriverInfo::GetDriverVendor(DriverVendor::MesaSWRast),
+                      mDriverVendor);
+      mIsAccelerated = false;
+    } else if (strcasestr(driDriver.get(), "vmwgfx")) {
+      CopyUTF16toUTF8(GfxDriverInfo::GetDriverVendor(DriverVendor::MesaVM),
+                      mDriverVendor);
+      mIsAccelerated = false;
+    } else if (!mIsAccelerated) {
+      CopyUTF16toUTF8(
+          GfxDriverInfo::GetDriverVendor(DriverVendor::MesaSWUnknown),
+          mDriverVendor);
+    } else if (!driDriver.IsEmpty()) {
+      mDriverVendor = nsPrintfCString("mesa/%s", driDriver.get());
+    } else {
+      // Some other mesa configuration where we couldn't get enough info.
+      NS_WARNING("Failed to detect Mesa driver being used!");
+      CopyUTF16toUTF8(GfxDriverInfo::GetDriverVendor(DriverVendor::MesaUnknown),
+                      mDriverVendor);
+    }
+
+    if (!mesaVendor.IsEmpty()) {
+      mVendorId = mesaVendor;
+    }
+
+    if (!mesaDevice.IsEmpty()) {
+      mDeviceId = mesaDevice;
+    }
+
+    if (!mIsAccelerated && mVendorId.IsEmpty()) {
+      mVendorId.Assign(glVendor.get());
+    }
+
+    if (!mIsAccelerated && mDeviceId.IsEmpty()) {
+      mDeviceId.Assign(glRenderer.get());
+    }
+  } else if (glVendor.EqualsLiteral("NVIDIA Corporation")) {
+    CopyUTF16toUTF8(GfxDriverInfo::GetDeviceVendor(DeviceVendor::NVIDIA),
+                    mVendorId);
+    mDriverVendor.AssignLiteral("nvidia/unknown");
+    // TODO: Use NV-CONTROL X11 extension to query Device ID and VRAM.
+  } else if (glVendor.EqualsLiteral("ATI Technologies Inc.")) {
+    CopyUTF16toUTF8(GfxDriverInfo::GetDeviceVendor(DeviceVendor::ATI),
+                    mVendorId);
+    mDriverVendor.AssignLiteral("ati/unknown");
+    // TODO: Look into ways to find the device ID on FGLRX.
+  } else {
+    NS_WARNING("Failed to detect GL vendor!");
+  }
+
+  if (!adapterRam.IsEmpty()) {
+    mAdapterRAM = (uint32_t)atoi(adapterRam.get());
+  }
+
+  // If we have the DRI driver, we can derive the vendor ID from that if needed.
+  if (mVendorId.IsEmpty() && !driDriver.IsEmpty()) {
+    const char* nvidiaDrivers[] = {"nouveau", "tegra", nullptr};
+    for (size_t i = 0; nvidiaDrivers[i]; ++i) {
+      if (driDriver.Equals(nvidiaDrivers[i])) {
+        CopyUTF16toUTF8(GfxDriverInfo::GetDeviceVendor(DeviceVendor::NVIDIA),
+                        mVendorId);
+        break;
+      }
+    }
+
+    if (mVendorId.IsEmpty()) {
+      const char* intelDrivers[] = {"iris", "crocus", "i915", "i965",
+                                    "i810", "intel",  nullptr};
+      for (size_t i = 0; intelDrivers[i]; ++i) {
+        if (driDriver.Equals(intelDrivers[i])) {
+          CopyUTF16toUTF8(GfxDriverInfo::GetDeviceVendor(DeviceVendor::Intel),
+                          mVendorId);
+          break;
+        }
+      }
+    }
+
+    if (mVendorId.IsEmpty()) {
+      const char* amdDrivers[] = {"r600",   "r200",     "r100",
+                                  "radeon", "radeonsi", nullptr};
+      for (size_t i = 0; amdDrivers[i]; ++i) {
+        if (driDriver.Equals(amdDrivers[i])) {
+          CopyUTF16toUTF8(GfxDriverInfo::GetDeviceVendor(DeviceVendor::ATI),
+                          mVendorId);
+          break;
+        }
+      }
+    }
+
+    if (mVendorId.IsEmpty()) {
+      if (driDriver.EqualsLiteral("freedreno")) {
+        CopyUTF16toUTF8(GfxDriverInfo::GetDeviceVendor(DeviceVendor::Qualcomm),
+                        mVendorId);
+      }
+    }
+  }
+
+  // If we still don't have a vendor ID, we can try the PCI vendor list.
+  if (mVendorId.IsEmpty()) {
+    if (pciVendors.IsEmpty()) {
+      gfxCriticalNote << "No GPUs detected via PCI\n";
+    } else {
+      for (size_t i = 0; i < pciVendors.Length(); ++i) {
+        if (mVendorId.IsEmpty()) {
+          mVendorId = pciVendors[i];
+        } else if (mVendorId != pciVendors[i]) {
+          gfxCriticalNote << "More than 1 GPU vendor detected via PCI, cannot "
+                             "deduce vendor\n";
+          mVendorId.Truncate();
+          break;
+        }
+      }
+    }
+  }
+
+  // If we know the vendor ID, but didn't get a device ID, we can guess from the
+  // PCI device list.
+  if (mDeviceId.IsEmpty() && !mVendorId.IsEmpty()) {
+    for (size_t i = 0; i < pciLen; ++i) {
+      if (mVendorId.Equals(pciVendors[i])) {
+        if (mDeviceId.IsEmpty()) {
+          mDeviceId = pciDevices[i];
+        } else if (mDeviceId != pciDevices[i]) {
+          gfxCriticalNote << "More than 1 GPU from same vendor detected via "
+                             "PCI, cannot deduce device\n";
+          mDeviceId.Truncate();
+          break;
+        }
+      }
+    }
+  }
+
+  // Assuming we know the vendor, we should check for a secondary card.
+  if (!mVendorId.IsEmpty()) {
+    if (pciLen > 2) {
+      gfxCriticalNote
+          << "More than 2 GPUs detected via PCI, secondary GPU is arbitrary\n";
+    }
+    for (size_t i = 0; i < pciLen; ++i) {
+      if (!mVendorId.Equals(pciVendors[i]) ||
+          (!mDeviceId.IsEmpty() && !mDeviceId.Equals(pciDevices[i]))) {
+        mSecondaryVendorId = pciVendors[i];
+        mSecondaryDeviceId = pciDevices[i];
+        break;
+      }
+    }
+  }
+
+  // If we couldn't choose, log them.
+  if (mVendorId.IsEmpty()) {
+    for (size_t i = 0; i < pciLen; ++i) {
+      gfxCriticalNote << "PCI candidate " << pciVendors[i].get() << "/"
+                      << pciDevices[i].get() << "\n";
+    }
+  }
+
+  // Fallback to GL_VENDOR and GL_RENDERER.
+  if (mVendorId.IsEmpty()) {
+    mVendorId.Assign(glVendor.get());
+  }
+  if (mDeviceId.IsEmpty()) {
+    mDeviceId.Assign(glRenderer.get());
+  }
+
+  mAdapterDescription.Assign(glRenderer);
+
+  // Make a best effort guess at whether or not we are using the XWayland compat
+  // layer. For all intents and purposes, we should otherwise believe we are
+  // using X11.
+  mIsWayland = GdkIsWaylandDisplay();
+  mIsXWayland = IsXWaylandProtocol();
+
+  if (!ddxDriver.IsEmpty()) {
+    PRInt32 start = 0;
+    PRInt32 loc = ddxDriver.Find(";", start);
+    while (loc != kNotFound) {
+      nsCString line(ddxDriver.get() + start, loc - start);
+      mDdxDrivers.AppendElement(std::move(line));
+
+      start = loc + 1;
+      loc = ddxDriver.Find(";", start);
+    }
+  }
+
+  if (error || errorLog || mTestType.IsEmpty()) {
+    if (!mAdapterDescription.IsEmpty()) {
+      mAdapterDescription.AppendLiteral(" (See failure log)");
+    } else {
+      mAdapterDescription.AppendLiteral("See failure log");
+    }
+
+    mGlxTestError = true;
+  }
+
+  AddCrashReportAnnotations();
+}
+
+int GfxInfo::FireTestProcess(const nsAString& aBinaryFile, int* aOutPipe,
+                             const char** aStringArgs) {
+  nsCOMPtr<nsIFile> appFile;
+  nsresult rv = XRE_GetBinaryPath(getter_AddRefs(appFile));
+  if (NS_FAILED(rv)) {
+    gfxCriticalNote << "Couldn't find application file.\n";
+    return false;
+  }
+  nsCOMPtr<nsIFile> exePath;
+  rv = appFile->GetParent(getter_AddRefs(exePath));
+  if (NS_FAILED(rv)) {
+    gfxCriticalNote << "Couldn't get application directory.\n";
+    return false;
+  }
+  exePath->Append(aBinaryFile);
+
+#define MAX_ARGS 8
+  char* argv[MAX_ARGS + 2];
+
+  argv[0] = strdup(exePath->NativePath().get());
+  for (int i = 0; i < MAX_ARGS; i++) {
+    if (aStringArgs[i]) {
+      argv[i + 1] = strdup(aStringArgs[i]);
+    } else {
+      argv[i + 1] = nullptr;
+      break;
+    }
+  }
+
+  // Use G_SPAWN_LEAVE_DESCRIPTORS_OPEN | G_SPAWN_DO_NOT_REAP_CHILD flags
+  // to g_spawn_async_with_pipes() run posix_spawn() directly.
+  int pid;
+  GUniquePtr<GError> err;
+  g_spawn_async_with_pipes(
+      nullptr, argv, nullptr,
+      GSpawnFlags(G_SPAWN_LEAVE_DESCRIPTORS_OPEN | G_SPAWN_DO_NOT_REAP_CHILD),
+      nullptr, nullptr, &pid, nullptr, aOutPipe, nullptr,
+      getter_Transfers(err));
+  if (err) {
+    gfxCriticalNote << "FireTestProcess failed: " << err->message << "\n";
+    pid = 0;
+  }
+  for (auto& arg : argv) {
+    if (!arg) {
+      break;
+    }
+    free(arg);
+  }
+  return pid;
+}
+
+bool GfxInfo::FireGLXTestProcess() {
+  if (sGLXTestPID != 0) {
+    return true;
+  }
+
+  int pfd[2];
+  if (pipe(pfd) == -1) {
+    gfxCriticalNote << "FireGLXTestProcess failed to create pipe\n";
+    return false;
+  }
+  sGLXTestPipe = pfd[0];
+
+  auto pipeID = std::to_string(pfd[1]);
+  const char* args[] = {"-f", pipeID.c_str(),
+                        IsWaylandEnabled() ? "-w" : nullptr, nullptr};
+  sGLXTestPID = FireTestProcess(GLX_PROBE_BINARY, nullptr, args);
+  // Set pid to -1 to avoid further test launch.
+  if (!sGLXTestPID) {
+    sGLXTestPID = -1;
+  }
+  close(pfd[1]);
+  return true;
+}
+
+void GfxInfo::GetDataVAAPI() {
+  if (mIsVAAPISupported.isSome()) {
+    return;
+  }
+  mIsVAAPISupported = Some(false);
+
+#ifdef MOZ_ENABLE_VAAPI
+  char* vaapiData = nullptr;
+  auto free = mozilla::MakeScopeExit([&] { g_free((void*)vaapiData); });
+
+  int vaapiPipe = -1;
+  int vaapiPID = 0;
+  const char* args[] = {"-d", mDrmRenderDevice.get(), nullptr};
+  vaapiPID = FireTestProcess(VAAPI_PROBE_BINARY, &vaapiPipe, args);
+  if (!vaapiPID) {
+    return;
+  }
+
+  if (!ManageChildProcess("vaapitest", &vaapiPID, &vaapiPipe,
+                          VAAPI_TEST_TIMEOUT, &vaapiData)) {
+    gfxCriticalNote << "vaapitest: ManageChildProcess failed\n";
+    return;
+  }
+
+  char* bufptr = vaapiData;
+  char* line;
+  while ((line = NS_strtok("\n", &bufptr))) {
+    if (!strcmp(line, "VAAPI_SUPPORTED")) {
+      line = NS_strtok("\n", &bufptr);
+      if (!line) {
+        gfxCriticalNote << "vaapitest: Failed to get VAAPI support\n";
+        return;
+      }
+      mIsVAAPISupported = Some(!strcmp(line, "TRUE"));
+    } else if (!strcmp(line, "VAAPI_HWCODECS")) {
+      line = NS_strtok("\n", &bufptr);
+      if (!line) {
+        gfxCriticalNote << "vaapitest: Failed to get VAAPI codecs\n";
+        return;
+      }
+
+      std::istringstream(line) >> mVAAPISupportedCodecs;
+      if (mVAAPISupportedCodecs & CODEC_HW_H264) {
+        media::MCSInfo::AddSupport(
+            media::MediaCodecsSupport::H264HardwareDecode);
+      }
+      if (mVAAPISupportedCodecs & CODEC_HW_VP8) {
+        media::MCSInfo::AddSupport(
+            media::MediaCodecsSupport::VP8HardwareDecode);
+      }
+      if (mVAAPISupportedCodecs & CODEC_HW_VP9) {
+        media::MCSInfo::AddSupport(
+            media::MediaCodecsSupport::VP9HardwareDecode);
+      }
+      if (mVAAPISupportedCodecs & CODEC_HW_AV1) {
+        media::MCSInfo::AddSupport(
+            media::MediaCodecsSupport::AV1HardwareDecode);
+      }
+    } else if (!strcmp(line, "WARNING") || !strcmp(line, "ERROR")) {
+      gfxCriticalNote << "vaapitest: " << line;
+      line = NS_strtok("\n", &bufptr);
+      if (line) {
+        gfxCriticalNote << "vaapitest: " << line << "\n";
+      }
+      return;
+    }
+  }
+#endif
+}
+
+// Probe all V4L2 devices and check their capabilities
+void GfxInfo::GetDataV4L2() {
+  if (mIsV4L2Supported.isSome()) {
+    // We have already probed v4l2 support, no need to do it again.
+    return;
+  }
+  mIsV4L2Supported = Some(false);
+
+#ifdef MOZ_ENABLE_V4L2
+  DIR* dir = opendir("/dev");
+  if (!dir) {
+    gfxCriticalNote << "Could not list /dev\n";
+    return;
+  }
+  struct dirent* dir_entry;
+  while ((dir_entry = readdir(dir))) {
+    if (!strncmp(dir_entry->d_name, "video", 5)) {
+      nsCString path = "/dev/"_ns;
+      path += nsDependentCString(dir_entry->d_name);
+      V4L2ProbeDevice(path);
+    }
+  }
+  closedir(dir);
+#endif  // MOZ_ENABLE_V4L2
+}
+
+// Check the capabilities of a single V4L2 device.  If the device doesn't work
+// or doesn't support any codecs we recognise, then we just ignore it.  If it
+// does support recognised codecs then add these codecs to the supported list
+// and mark V4L2 as supported: We only need a single working device to enable
+// V4L2, when we come to decode FFmpeg will probe all the devices and choose
+// the appropriate one.
+void GfxInfo::V4L2ProbeDevice(nsCString& dev) {
+  char* v4l2Data = nullptr;
+  auto free = mozilla::MakeScopeExit([&] { g_free((void*)v4l2Data); });
+
+  int v4l2Pipe = -1;
+  int v4l2PID = 0;
+  const char* args[] = {"-d", dev.get(), nullptr};
+  v4l2PID = FireTestProcess(V4L2_PROBE_BINARY, &v4l2Pipe, args);
+  if (!v4l2PID) {
+    gfxCriticalNote << "Failed to start v4l2test process\n";
+    return;
+  }
+
+  if (!ManageChildProcess("v4l2test", &v4l2PID, &v4l2Pipe, V4L2_TEST_TIMEOUT,
+                          &v4l2Data)) {
+    gfxCriticalNote << "v4l2test: ManageChildProcess failed\n";
+    return;
+  }
+
+  char* bufptr = v4l2Data;
+  char* line;
+  nsTArray<nsCString> capFormats;
+  nsTArray<nsCString> outFormats;
+  bool supported = false;
+  // Use gfxWarning rather than gfxCriticalNote from here on because the
+  // errors/warnings output by v4l2test are generally just caused by devices
+  // which aren't M2M decoders. Set gfx.logging.level=5 to see these messages.
+
+  while ((line = NS_strtok("\n", &bufptr))) {
+    if (!strcmp(line, "V4L2_SUPPORTED")) {
+      line = NS_strtok("\n", &bufptr);
+      if (!line) {
+        gfxWarning() << "v4l2test: Failed to get V4L2 support\n";
+        return;
+      }
+      supported = !strcmp(line, "TRUE");
+    } else if (!strcmp(line, "V4L2_CAPTURE_FMTS")) {
+      line = NS_strtok("\n", &bufptr);
+      if (!line) {
+        gfxWarning() << "v4l2test: Failed to get V4L2 CAPTURE formats\n";
+        return;
+      }
+      char* capture_fmt;
+      while ((capture_fmt = NS_strtok(" ", &line))) {
+        capFormats.AppendElement(capture_fmt);
+      }
+    } else if (!strcmp(line, "V4L2_OUTPUT_FMTS")) {
+      line = NS_strtok("\n", &bufptr);
+      if (!line) {
+        gfxWarning() << "v4l2test: Failed to get V4L2 OUTPUT formats\n";
+        return;
+      }
+      char* output_fmt;
+      while ((output_fmt = NS_strtok(" ", &line))) {
+        outFormats.AppendElement(output_fmt);
+      }
+    } else if (!strcmp(line, "WARNING") || !strcmp(line, "ERROR")) {
+      line = NS_strtok("\n", &bufptr);
+      if (line) {
+        gfxWarning() << "v4l2test: " << line << "\n";
+      }
+      return;
+    }
+  }
+
+  // If overall SUPPORTED flag is not TRUE then stop now
+  if (!supported) {
+    return;
+  }
+
+  // Currently the V4L2 decode platform only supports YUV420 and NV12
+  if (!capFormats.Contains("YV12") && !capFormats.Contains("NV12")) {
+    return;
+  }
+
+  // Supported codecs
+  if (outFormats.Contains("H264")) {
+    mIsV4L2Supported = Some(true);
+    media::MCSInfo::AddSupport(media::MediaCodecsSupport::H264HardwareDecode);
+    mV4L2SupportedCodecs |= CODEC_HW_H264;
+  }
+}
+
+const nsTArray<GfxDriverInfo>& GfxInfo::GetGfxDriverInfo() {
+  if (!sDriverInfo->Length()) {
+    // Mesa 10.0 provides the GLX_MESA_query_renderer extension, which allows us
+    // to query device IDs backing a GL context for blocklisting.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::All,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(10, 0, 0, 0), "FEATURE_FAILURE_OLD_MESA", "Mesa 10.0");
+
+    // NVIDIA Mesa baseline (see bug 1714391).
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaNouveau, DeviceFamily::All,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(11, 0, 0, 0), "FEATURE_FAILURE_OLD_NV_MESA", "Mesa 11.0");
+
+    // NVIDIA baseline (ported from old blocklist)
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::NonMesaAll, DeviceFamily::NvidiaAll,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(257, 21, 0, 0), "FEATURE_FAILURE_OLD_NVIDIA", "NVIDIA 257.21");
+
+    // fglrx baseline (chosen arbitrarily as 2013-07-22 release).
+    APPEND_TO_DRIVER_BLOCKLIST(
+        OperatingSystem::Linux, DeviceFamily::AtiAll,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(13, 15, 100, 1), "FEATURE_FAILURE_OLD_FGLRX", "fglrx 13.15.100.1");
+
+    ////////////////////////////////////
+    // FEATURE_WEBRENDER
+
+    // All Mesa software drivers, they should get Software WebRender instead.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::SoftwareMesaAll, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0), "FEATURE_FAILURE_SOFTWARE_GL",
+        "");
+
+    // Older generation Intel devices do not perform well with WebRender.
+    APPEND_TO_DRIVER_BLOCKLIST(
+        OperatingSystem::Linux, DeviceFamily::IntelWebRenderBlocked,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0), "INTEL_DEVICE_GEN5_OR_OLDER",
+        "");
+
+    // Nvidia Mesa baseline, see bug 1563859.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_WEBRENDER,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(18, 2, 0, 0), "FEATURE_FAILURE_WEBRENDER_OLD_MESA", "Mesa 18.2.0.0");
+
+    // Disable on all older Nvidia drivers due to stability issues.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::NonMesaAll, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, V(470, 82, 0, 0),
+        "FEATURE_FAILURE_WEBRENDER_OLD_NVIDIA", "470.82.0");
+
+    // Older generation NVIDIA devices do not perform well with WebRender.
+    APPEND_TO_DRIVER_BLOCKLIST(
+        OperatingSystem::Linux, DeviceFamily::NvidiaWebRenderBlocked,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0),
+        "NVIDIA_EARLY_TESLA_AND_C67_C68", "");
+
+    // Mesa baseline, chosen arbitrarily. Linux users are generally good about
+    // updating their Mesa libraries so we don't want to arbitarily support
+    // WebRender on old drivers with outstanding bugs to work around.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_WEBRENDER,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(17, 0, 0, 0), "FEATURE_FAILURE_WEBRENDER_OLD_MESA", "Mesa 17.0.0.0");
+
+    // Mesa baseline for non-Intel/NVIDIA/ATI devices. These other devices will
+    // often have less mature drivers so let's block older Mesa versions.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaNonIntelNvidiaAtiAll,
+        DeviceFamily::All, nsIGfxInfo::FEATURE_WEBRENDER,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(22, 2, 0, 0), "FEATURE_FAILURE_WEBRENDER_OLD_MESA_OTHER",
+        "Mesa 22.2.0.0");
+
+    // Bug 1690568 / Bug 1393793 - Require Mesa 17.3.0+ for devices using the
+    // AMD r600 driver to avoid shader compilation issues.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaR600, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_WEBRENDER,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(17, 3, 0, 0), "FEATURE_FAILURE_WEBRENDER_OLD_MESA_R600",
+        "Mesa 17.3.0.0");
+
+    // Disable on all ATI devices not using Mesa for now.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::NonMesaAll, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0),
+        "FEATURE_FAILURE_WEBRENDER_NO_LINUX_ATI", "");
+
+    // Disable R600 GPUs with Mesa drivers.
+    // Bug 1673939 - Garbled text on RS880 GPUs with Mesa drivers.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::AmdR600,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0),
+        "FEATURE_FAILURE_WEBRENDER_BUG_1673939",
+        "https://gitlab.freedesktop.org/mesa/mesa/-/issues/3720");
+
+    // Bug 1635186 - Poor performance with video playing in a background window
+    // on XWayland. Keep in sync with FEATURE_X11_EGL below to only enable them
+    // together by default. Only Mesa and Nvidia binary drivers are expected
+    // on Wayland rigth now.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::XWayland, DriverVendor::MesaAll, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_WEBRENDER,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(21, 0, 0, 0), "FEATURE_FAILURE_WEBRENDER_BUG_1635186",
+        "Mesa 21.0.0.0");
+
+    // Bug 1815481 - Disable mesa drivers in virtual machines.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaVM, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0),
+        "FEATURE_FAILURE_WEBRENDER_MESA_VM", "");
+    // Disable hardware mesa drivers in virtual machines due to instability.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaVM, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_WEBGL_USE_HARDWARE,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_FAILURE_WEBGL_MESA_VM", "");
+
+    ////////////////////////////////////
+    // FEATURE_WEBRENDER_COMPOSITOR
+    APPEND_TO_DRIVER_BLOCKLIST(
+        OperatingSystem::Linux, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_WEBRENDER_COMPOSITOR,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_FAILURE_WEBRENDER_COMPOSITOR_DISABLED", "");
+
+    ////////////////////////////////////
+    // FEATURE_X11_EGL
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_X11_EGL, nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+        DRIVER_LESS_THAN, V(17, 0, 0, 0), "FEATURE_X11_EGL_OLD_MESA",
+        "Mesa 17.0.0.0");
+
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_X11_EGL, nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+        DRIVER_LESS_THAN, V(18, 2, 0, 0), "FEATURE_X11_EGL_OLD_MESA_NOUVEAU",
+        "Mesa 18.2.0.0");
+
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::NonMesaAll, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_X11_EGL, nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+        DRIVER_LESS_THAN, V(470, 82, 0, 0),
+        "FEATURE_ROLLOUT_X11_EGL_NVIDIA_BINARY", "470.82.0");
+
+    // Disable on all AMD devices not using Mesa.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::NonMesaAll, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_X11_EGL, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0),
+        "FEATURE_FAILURE_X11_EGL_NO_LINUX_ATI", "");
+
+    ////////////////////////////////////
+    // FEATURE_DMABUF
+#ifdef EARLY_BETA_OR_EARLIER
+    // Disabled due to high volume crash tracked in bug 1788573, fixed in the
+    // 545 driver.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::NonMesaAll, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_DMABUF, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, V(545, 23, 6, 0), "FEATURE_FAILURE_BUG_1788573", "");
+#else
+    // Disabled due to high volume crash tracked in bug 1788573.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::NonMesaAll, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_DMABUF, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0), "FEATURE_FAILURE_BUG_1788573",
+        "");
+#endif
+
+    ////////////////////////////////////
+    // FEATURE_DMABUF_SURFACE_EXPORT
+    // Disabled due to:
+    // https://gitlab.freedesktop.org/mesa/mesa/-/issues/6666
+    // https://gitlab.freedesktop.org/mesa/mesa/-/issues/6796
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_DMABUF_SURFACE_EXPORT,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_FAILURE_BROKEN_DRIVER", "");
+
+    // Disabled due to:
+    // https://gitlab.freedesktop.org/mesa/mesa/-/issues/6688
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::IntelAll,
+        nsIGfxInfo::FEATURE_DMABUF_SURFACE_EXPORT,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_FAILURE_BROKEN_DRIVER", "");
+
+    // Disabled due to:
+    // https://gitlab.freedesktop.org/mesa/mesa/-/issues/6988
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::QualcommAll,
+        nsIGfxInfo::FEATURE_DMABUF_SURFACE_EXPORT,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_FAILURE_BROKEN_DRIVER", "");
+
+    ////////////////////////////////////
+    // FEATURE_HARDWARE_VIDEO_DECODING
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(21, 0, 0, 0), "FEATURE_HARDWARE_VIDEO_DECODING_MESA",
+        "Mesa 21.0.0.0");
+
+    // Disable on all NVIDIA hardware
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::All, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_HARDWARE_VIDEO_DECODING_NO_LINUX_NVIDIA", "");
+
+    // Disable on all AMD devices not using Mesa.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::NonMesaAll, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_HARDWARE_VIDEO_DECODING_NO_LINUX_AMD", "");
+
+    // Disable on r600 driver due to decoding artifacts (Bug 1824307)
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaR600, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_HARDWARE_VIDEO_DECODING_NO_R600", "");
+
+    // Disable on AMD devices using broken Mesa (Bug 1832080).
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_LESS_THAN, V(23, 1, 1, 0),
+        "FEATURE_HARDWARE_VIDEO_DECODING_AMD_DISABLE", "Mesa 23.1.1.0");
+
+    // Disable on Release/late Beta on AMD
+#if !defined(EARLY_BETA_OR_EARLIER)
+    APPEND_TO_DRIVER_BLOCKLIST(OperatingSystem::Linux, DeviceFamily::AtiAll,
+                               nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+                               nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+                               DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0),
+                               "FEATURE_HARDWARE_VIDEO_DECODING_DISABLE", "");
+#endif
+    ////////////////////////////////////
+    // FEATURE_HW_DECODED_VIDEO_ZERO_COPY - ALLOWLIST
+    APPEND_TO_DRIVER_BLOCKLIST2(OperatingSystem::Linux, DeviceFamily::All,
+                                nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY,
+                                nsIGfxInfo::FEATURE_ALLOW_ALWAYS,
+                                DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0),
+                                "FEATURE_ROLLOUT_ALL");
+
+    // Disable on AMD devices using broken Mesa (Bug 1837138).
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaAll, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_LESS_THAN, V(23, 1, 1, 0),
+        "FEATURE_HARDWARE_VIDEO_ZERO_COPY_LINUX_AMD_DISABLE", "Mesa 23.1.1.0");
+
+    ////////////////////////////////////
+    // FEATURE_WEBRENDER_PARTIAL_PRESENT
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::X11, DriverVendor::NonMesaAll, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_WEBRENDER_PARTIAL_PRESENT,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_ROLLOUT_WR_PARTIAL_PRESENT_NVIDIA_BINARY", "");
+
+    ////////////////////////////////////
+
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::MesaNouveau, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_THREADSAFE_GL, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0),
+        "FEATURE_FAILURE_THREADSAFE_GL_NOUVEAU", "");
+
+#ifdef EARLY_BETA_OR_EARLIER
+    // Disabled due to high volume crash tracked in bug 1788573, fixed in the
+    // 545 driver.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::NonMesaAll, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_THREADSAFE_GL, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, V(545, 23, 6, 0), "FEATURE_FAILURE_BUG_1788573", "");
+#else
+    // Disabled due to high volume crash tracked in bug 1788573.
+    APPEND_TO_DRIVER_BLOCKLIST_EXT(
+        OperatingSystem::Linux, ScreenSizeStatus::All, BatteryStatus::All,
+        WindowProtocol::All, DriverVendor::NonMesaAll, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_THREADSAFE_GL, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0), "FEATURE_FAILURE_BUG_1788573",
+        "");
+#endif
+
+    // AMD R600 family does not perform well with WebRender.
+    APPEND_TO_DRIVER_BLOCKLIST(
+        OperatingSystem::Linux, DeviceFamily::AmdR600,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0), "AMD_R600_FAMILY", "");
+  }
+  return *sDriverInfo;
+}
+
+bool GfxInfo::DoesWindowProtocolMatch(const nsAString& aBlocklistWindowProtocol,
+                                      const nsAString& aWindowProtocol) {
+  if (mIsWayland &&
+      aBlocklistWindowProtocol.Equals(
+          GfxDriverInfo::GetWindowProtocol(WindowProtocol::WaylandAll),
+          nsCaseInsensitiveStringComparator)) {
+    return true;
+  }
+  if (!mIsWayland &&
+      aBlocklistWindowProtocol.Equals(
+          GfxDriverInfo::GetWindowProtocol(WindowProtocol::X11All),
+          nsCaseInsensitiveStringComparator)) {
+    return true;
+  }
+  return GfxInfoBase::DoesWindowProtocolMatch(aBlocklistWindowProtocol,
+                                              aWindowProtocol);
+}
+
+bool GfxInfo::DoesDriverVendorMatch(const nsAString& aBlocklistVendor,
+                                    const nsAString& aDriverVendor) {
+  if (mIsMesa) {
+    if (aBlocklistVendor.Equals(
+            GfxDriverInfo::GetDriverVendor(DriverVendor::MesaAll),
+            nsCaseInsensitiveStringComparator)) {
+      return true;
+    }
+    if (mIsAccelerated &&
+        aBlocklistVendor.Equals(
+            GfxDriverInfo::GetDriverVendor(DriverVendor::HardwareMesaAll),
+            nsCaseInsensitiveStringComparator)) {
+      return true;
+    }
+    if (!mIsAccelerated &&
+        aBlocklistVendor.Equals(
+            GfxDriverInfo::GetDriverVendor(DriverVendor::SoftwareMesaAll),
+            nsCaseInsensitiveStringComparator)) {
+      return true;
+    }
+    if (aBlocklistVendor.Equals(GfxDriverInfo::GetDriverVendor(
+                                    DriverVendor::MesaNonIntelNvidiaAtiAll),
+                                nsCaseInsensitiveStringComparator)) {
+      return !mVendorId.Equals("0x8086") && !mVendorId.Equals("0x10de") &&
+             !mVendorId.Equals("0x1002");
+    }
+  }
+  if (!mIsMesa && aBlocklistVendor.Equals(
+                      GfxDriverInfo::GetDriverVendor(DriverVendor::NonMesaAll),
+                      nsCaseInsensitiveStringComparator)) {
+    return true;
+  }
+  return GfxInfoBase::DoesDriverVendorMatch(aBlocklistVendor, aDriverVendor);
+}
+
+nsresult GfxInfo::GetFeatureStatusImpl(
+    int32_t aFeature, int32_t* aStatus, nsAString& aSuggestedDriverVersion,
+    const nsTArray<GfxDriverInfo>& aDriverInfo, nsACString& aFailureId,
+    OperatingSystem* aOS /* = nullptr */)
+
+{
+  NS_ENSURE_ARG_POINTER(aStatus);
+  *aStatus = nsIGfxInfo::FEATURE_STATUS_UNKNOWN;
+  aSuggestedDriverVersion.SetIsVoid(true);
+  OperatingSystem os = OperatingSystem::Linux;
+  if (aOS) *aOS = os;
+
+  if (sShutdownOccurred) {
+    return NS_OK;
+  }
+
+  GetData();
+
+  if (mGlxTestError) {
+    // If glxtest failed, block most features by default.
+    if (OnlyAllowFeatureOnKnownConfig(aFeature)) {
+      *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+      aFailureId = "FEATURE_FAILURE_GLXTEST_FAILED";
+    } else {
+      *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+    }
+    return NS_OK;
+  }
+
+  if (mGLMajorVersion == 1) {
+    // We're on OpenGL 1. In most cases that indicates really old hardware.
+    // We better block them, rather than rely on them to fail gracefully,
+    // because they don't! see bug 696636
+    if (OnlyAllowFeatureOnKnownConfig(aFeature)) {
+      *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+      aFailureId = "FEATURE_FAILURE_OPENGL_1";
+    } else {
+      *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+    }
+    return NS_OK;
+  }
+
+  // Blocklist software GL implementations from using layers acceleration.
+  // On the test infrastructure, we'll force-enable layers acceleration.
+  if (aFeature == nsIGfxInfo::FEATURE_OPENGL_LAYERS && !mIsAccelerated &&
+      !PR_GetEnv("MOZ_LAYERS_ALLOW_SOFTWARE_GL")) {
+    *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+    aFailureId = "FEATURE_FAILURE_SOFTWARE_GL";
+    return NS_OK;
+  }
+
+  if (aFeature == nsIGfxInfo::FEATURE_WEBRENDER) {
+    // Don't try Webrender on devices where we are guaranteed to fail.
+    if (mGLMajorVersion < 3) {
+      *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+      aFailureId = "FEATURE_FAILURE_OPENGL_LESS_THAN_3";
+      return NS_OK;
+    }
+
+    // Bug 1710400: Disable Webrender on the deprecated Intel DDX driver
+    for (const nsCString& driver : mDdxDrivers) {
+      if (strcasestr(driver.get(), "Intel")) {
+        *aStatus = nsIGfxInfo::FEATURE_BLOCKED_DEVICE;
+        aFailureId = "FEATURE_FAILURE_DDX_INTEL";
+        return NS_OK;
+      }
+    }
+  }
+
+  const struct {
+    int32_t mFeature;
+    int32_t mCodec;
+  } kFeatureToCodecs[] = {{nsIGfxInfo::FEATURE_H264_HW_DECODE, CODEC_HW_H264},
+                          {nsIGfxInfo::FEATURE_VP8_HW_DECODE, CODEC_HW_VP8},
+                          {nsIGfxInfo::FEATURE_VP9_HW_DECODE, CODEC_HW_VP9},
+                          {nsIGfxInfo::FEATURE_AV1_HW_DECODE, CODEC_HW_AV1}};
+
+  for (const auto& pair : kFeatureToCodecs) {
+    if (aFeature != pair.mFeature) {
+      continue;
+    }
+    if ((mVAAPISupportedCodecs & pair.mCodec) ||
+        (mV4L2SupportedCodecs & pair.mCodec)) {
+      *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+    } else {
+      *aStatus = nsIGfxInfo::FEATURE_BLOCKED_PLATFORM_TEST;
+      aFailureId = "FEATURE_FAILURE_VIDEO_DECODING_MISSING";
+    }
+    return NS_OK;
+  }
+
+  auto ret = GfxInfoBase::GetFeatureStatusImpl(
+      aFeature, aStatus, aSuggestedDriverVersion, aDriverInfo, aFailureId, &os);
+
+  // Probe VA-API/V4L2 on supported devices only
+  if (aFeature == nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING) {
+    if (!StaticPrefs::media_hardware_video_decoding_enabled_AtStartup()) {
+      return ret;
+    }
+    bool probeHWDecode =
+        mIsAccelerated &&
+        (*aStatus == nsIGfxInfo::FEATURE_STATUS_OK ||
+         StaticPrefs::media_hardware_video_decoding_force_enabled_AtStartup() ||
+         StaticPrefs::media_ffmpeg_vaapi_enabled_AtStartup());
+    if (probeHWDecode) {
+      GetDataVAAPI();
+      GetDataV4L2();
+    } else {
+      mIsVAAPISupported = Some(false);
+      mIsV4L2Supported = Some(false);
+    }
+    if (!mIsVAAPISupported.value() && !mIsV4L2Supported.value()) {
+      *aStatus = nsIGfxInfo::FEATURE_BLOCKED_PLATFORM_TEST;
+      aFailureId = "FEATURE_FAILURE_VIDEO_DECODING_TEST_FAILED";
+    }
+  }
+
+  return ret;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetD2DEnabled(bool* aEnabled) { return NS_ERROR_FAILURE; }
+
+NS_IMETHODIMP
+GfxInfo::GetDWriteEnabled(bool* aEnabled) { return NS_ERROR_FAILURE; }
+
+NS_IMETHODIMP
+GfxInfo::GetDWriteVersion(nsAString& aDwriteVersion) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP GfxInfo::GetHasBattery(bool* aHasBattery) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetEmbeddedInFirefoxReality(bool* aEmbeddedInFirefoxReality) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetCleartypeParameters(nsAString& aCleartypeParams) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetWindowProtocol(nsAString& aWindowProtocol) {
+  GetData();
+  if (mIsWayland) {
+    aWindowProtocol = GfxDriverInfo::GetWindowProtocol(WindowProtocol::Wayland);
+  } else if (mIsXWayland) {
+    aWindowProtocol =
+        GfxDriverInfo::GetWindowProtocol(WindowProtocol::XWayland);
+  } else {
+    aWindowProtocol = GfxDriverInfo::GetWindowProtocol(WindowProtocol::X11);
+  }
+  Telemetry::ScalarSet(Telemetry::ScalarID::GFX_LINUX_WINDOW_PROTOCOL,
+                       aWindowProtocol);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetTestType(nsAString& aTestType) {
+  GetData();
+  AppendASCIItoUTF16(mTestType, aTestType);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDescription(nsAString& aAdapterDescription) {
+  GetData();
+  AppendASCIItoUTF16(mAdapterDescription, aAdapterDescription);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDescription2(nsAString& aAdapterDescription) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterRAM(uint32_t* aAdapterRAM) {
+  GetData();
+  *aAdapterRAM = mAdapterRAM;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterRAM2(uint32_t* aAdapterRAM) { return NS_ERROR_FAILURE; }
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriver(nsAString& aAdapterDriver) {
+  aAdapterDriver.Truncate();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriver2(nsAString& aAdapterDriver) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVendor(nsAString& aAdapterDriverVendor) {
+  GetData();
+  CopyASCIItoUTF16(mDriverVendor, aAdapterDriverVendor);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVendor2(nsAString& aAdapterDriverVendor) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVersion(nsAString& aAdapterDriverVersion) {
+  GetData();
+  CopyASCIItoUTF16(mDriverVersion, aAdapterDriverVersion);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVersion2(nsAString& aAdapterDriverVersion) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverDate(nsAString& aAdapterDriverDate) {
+  aAdapterDriverDate.Truncate();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverDate2(nsAString& aAdapterDriverDate) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterVendorID(nsAString& aAdapterVendorID) {
+  GetData();
+  CopyUTF8toUTF16(mVendorId, aAdapterVendorID);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterVendorID2(nsAString& aAdapterVendorID) {
+  GetData();
+  CopyUTF8toUTF16(mSecondaryVendorId, aAdapterVendorID);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDeviceID(nsAString& aAdapterDeviceID) {
+  GetData();
+  CopyUTF8toUTF16(mDeviceId, aAdapterDeviceID);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDeviceID2(nsAString& aAdapterDeviceID) {
+  GetData();
+  CopyUTF8toUTF16(mSecondaryDeviceId, aAdapterDeviceID);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterSubsysID(nsAString& aAdapterSubsysID) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterSubsysID2(nsAString& aAdapterSubsysID) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetIsGPU2Active(bool* aIsGPU2Active) {
+  // This is never the case, as the active GPU should be the primary GPU.
+  *aIsGPU2Active = false;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetDrmRenderDevice(nsACString& aDrmRenderDevice) {
+  GetData();
+  aDrmRenderDevice.Assign(mDrmRenderDevice);
+  return NS_OK;
+}
+
+#ifdef DEBUG
+
+// Implement nsIGfxInfoDebug
+// We don't support spoofing anything on Linux
+
+NS_IMETHODIMP GfxInfo::SpoofVendorID(const nsAString& aVendorID) {
+  GetData();
+  CopyUTF16toUTF8(aVendorID, mVendorId);
+  mIsAccelerated = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofDeviceID(const nsAString& aDeviceID) {
+  GetData();
+  CopyUTF16toUTF8(aDeviceID, mDeviceId);
+  return NS_OK;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofDriverVersion(const nsAString& aDriverVersion) {
+  GetData();
+  CopyUTF16toUTF8(aDriverVersion, mDriverVersion);
+  return NS_OK;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofOSVersion(uint32_t aVersion) {
+  // We don't support OS versioning on Linux. There's just "Linux".
+  return NS_OK;
+}
+
+#endif
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/GfxInfo.h b/widget/gtk/GfxInfo.h
new file mode 100644
index 0000000000..26b4554b4a
--- /dev/null
+++ b/widget/gtk/GfxInfo.h
@@ -0,0 +1,137 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_GTK_GFXINFO_h__
+#define WIDGET_GTK_GFXINFO_h__
+
+#include "GfxInfoBase.h"
+#include "nsString.h"
+
+namespace mozilla {
+namespace widget {
+
+class GfxInfo final : public GfxInfoBase {
+ public:
+  // We only declare the subset of nsIGfxInfo that we actually implement. The
+  // rest is brought forward from GfxInfoBase.
+  NS_IMETHOD GetD2DEnabled(bool* aD2DEnabled) override;
+  NS_IMETHOD GetDWriteEnabled(bool* aDWriteEnabled) override;
+  NS_IMETHOD GetDWriteVersion(nsAString& aDwriteVersion) override;
+  NS_IMETHOD GetEmbeddedInFirefoxReality(
+      bool* aEmbeddedInFirefoxReality) override;
+  NS_IMETHOD GetHasBattery(bool* aHasBattery) override;
+  NS_IMETHOD GetCleartypeParameters(nsAString& aCleartypeParams) override;
+  NS_IMETHOD GetWindowProtocol(nsAString& aWindowProtocol) override;
+  NS_IMETHOD GetTestType(nsAString& aTestType) override;
+  NS_IMETHOD GetAdapterDescription(nsAString& aAdapterDescription) override;
+  NS_IMETHOD GetAdapterDriver(nsAString& aAdapterDriver) override;
+  NS_IMETHOD GetAdapterVendorID(nsAString& aAdapterVendorID) override;
+  NS_IMETHOD GetAdapterDeviceID(nsAString& aAdapterDeviceID) override;
+  NS_IMETHOD GetAdapterSubsysID(nsAString& aAdapterSubsysID) override;
+  NS_IMETHOD GetAdapterRAM(uint32_t* aAdapterRAM) override;
+  NS_IMETHOD GetAdapterDriverVendor(nsAString& aAdapterDriverVendor) override;
+  NS_IMETHOD GetAdapterDriverVersion(nsAString& aAdapterDriverVersion) override;
+  NS_IMETHOD GetAdapterDriverDate(nsAString& aAdapterDriverDate) override;
+  NS_IMETHOD GetAdapterDescription2(nsAString& aAdapterDescription) override;
+  NS_IMETHOD GetAdapterDriver2(nsAString& aAdapterDriver) override;
+  NS_IMETHOD GetAdapterVendorID2(nsAString& aAdapterVendorID) override;
+  NS_IMETHOD GetAdapterDeviceID2(nsAString& aAdapterDeviceID) override;
+  NS_IMETHOD GetAdapterSubsysID2(nsAString& aAdapterSubsysID) override;
+  NS_IMETHOD GetAdapterRAM2(uint32_t* aAdapterRAM) override;
+  NS_IMETHOD GetAdapterDriverVendor2(nsAString& aAdapterDriverVendor) override;
+  NS_IMETHOD GetAdapterDriverVersion2(
+      nsAString& aAdapterDriverVersion) override;
+  NS_IMETHOD GetAdapterDriverDate2(nsAString& aAdapterDriverDate) override;
+  NS_IMETHOD GetIsGPU2Active(bool* aIsGPU2Active) override;
+  NS_IMETHOD GetDrmRenderDevice(nsACString& aDrmRenderDevice) override;
+  using GfxInfoBase::GetFeatureStatus;
+  using GfxInfoBase::GetFeatureSuggestedDriverVersion;
+
+  virtual nsresult Init() override;
+
+  NS_IMETHOD_(void) GetData() override;
+
+  static bool FireGLXTestProcess();
+
+#ifdef DEBUG
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIGFXINFODEBUG
+#endif
+
+ protected:
+  ~GfxInfo() = default;
+
+  OperatingSystem GetOperatingSystem() override {
+    return OperatingSystem::Linux;
+  }
+  virtual nsresult GetFeatureStatusImpl(
+      int32_t aFeature, int32_t* aStatus, nsAString& aSuggestedDriverVersion,
+      const nsTArray<GfxDriverInfo>& aDriverInfo, nsACString& aFailureId,
+      OperatingSystem* aOS = nullptr) override;
+  virtual const nsTArray<GfxDriverInfo>& GetGfxDriverInfo() override;
+
+  virtual bool DoesWindowProtocolMatch(
+      const nsAString& aBlocklistWindowProtocol,
+      const nsAString& aWindowProtocol) override;
+
+  virtual bool DoesDriverVendorMatch(const nsAString& aBlocklistVendor,
+                                     const nsAString& aDriverVendor) override;
+  static int FireTestProcess(const nsAString& aBinaryFile, int* aOutPipe,
+                             const char** aStringArgs);
+
+ private:
+  bool mInitialized = false;
+  nsCString mVendorId;
+  nsCString mDeviceId;
+  nsCString mDriverVendor;
+  nsCString mDriverVersion;
+  nsCString mAdapterDescription;
+  uint32_t mAdapterRAM;
+  nsCString mOS;
+  nsCString mOSRelease;
+  nsCString mTestType;
+
+  nsCString mSecondaryVendorId;
+  nsCString mSecondaryDeviceId;
+
+  nsCString mDrmRenderDevice;
+
+  nsTArray<nsCString> mDdxDrivers;
+
+  struct ScreenInfo {
+    uint32_t mWidth;
+    uint32_t mHeight;
+    bool mIsDefault;
+  };
+
+  nsTArray<ScreenInfo> mScreenInfo;
+  bool mHasTextureFromPixmap;
+  unsigned int mGLMajorVersion, mGLMinorVersion;
+  bool mIsMesa;
+  bool mIsAccelerated;
+  bool mIsWayland;
+  bool mIsXWayland;
+  bool mHasMultipleGPUs;
+  bool mGlxTestError;
+  mozilla::Maybe<bool> mIsVAAPISupported;
+  int mVAAPISupportedCodecs = 0;
+  mozilla::Maybe<bool> mIsV4L2Supported;
+  int mV4L2SupportedCodecs = 0;
+
+  static int sGLXTestPipe;
+  static pid_t sGLXTestPID;
+
+  void GetDataVAAPI();
+  void GetDataV4L2();
+  void V4L2ProbeDevice(nsCString& dev);
+  void AddCrashReportAnnotations();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* WIDGET_GTK_GFXINFO_h__ */
diff --git a/widget/gtk/GfxInfoUtils.h b/widget/gtk/GfxInfoUtils.h
new file mode 100644
index 0000000000..f4d96604e3
--- /dev/null
+++ b/widget/gtk/GfxInfoUtils.h
@@ -0,0 +1,98 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_GTK_GFXINFO_UTILS_h__
+#define WIDGET_GTK_GFXINFO_UTILS_h__
+
+// An alternative to mozilla::Unused for use in (a) C code and (b) code where
+// linking with unused.o is difficult.
+#define MOZ_UNUSED(expr) \
+  do {                   \
+    if (expr) {          \
+      (void)0;           \
+    }                    \
+  } while (0)
+
+#define LOG_PIPE 2
+
+static bool enable_logging = false;
+static void log(const char* format, ...) {
+  if (!enable_logging) {
+    return;
+  }
+  va_list args;
+  va_start(args, format);
+  vfprintf(stderr, format, args);
+  va_end(args);
+}
+
+static int output_pipe = 1;
+static void close_logging() {
+  // we want to redirect to /dev/null stdout, stderr, and while we're at it,
+  // any PR logging file descriptors. To that effect, we redirect all positive
+  // file descriptors up to what open() returns here. In particular, 1 is stdout
+  // and 2 is stderr.
+  int fd = open("/dev/null", O_WRONLY);
+  for (int i = 1; i < fd; i++) {
+    if (output_pipe != i) {
+      dup2(fd, i);
+    }
+  }
+  close(fd);
+}
+
+// C++ standard collides with C standard in that it doesn't allow casting void*
+// to function pointer types. So the work-around is to convert first to size_t.
+// http://www.trilithium.com/johan/2004/12/problem-with-dlsym/
+template <typename func_ptr_type>
+static func_ptr_type cast(void* ptr) {
+  return reinterpret_cast<func_ptr_type>(reinterpret_cast<size_t>(ptr));
+}
+
+#define BUFFER_SIZE_STEP 4000
+
+static char* test_buf = nullptr;
+static int test_bufsize = 0;
+static int test_length = 0;
+
+static void record_value(const char* format, ...) {
+  if (!test_buf || test_length + BUFFER_SIZE_STEP / 2 > test_bufsize) {
+    test_bufsize += BUFFER_SIZE_STEP;
+    test_buf = (char*)realloc(test_buf, test_bufsize);
+  }
+  int remaining = test_bufsize - test_length;
+
+  // Append the new values to the buffer, not to exceed the remaining space.
+  va_list args;
+  va_start(args, format);
+  int max_added = vsnprintf(test_buf + test_length, remaining, format, args);
+  va_end(args);
+
+  if (max_added >= remaining) {
+    test_length += remaining;
+  } else {
+    test_length += max_added;
+  }
+}
+
+#define record_error(str_, ...) record_value("ERROR\n" str_ "\n", ##__VA_ARGS__)
+#define record_warning(str_, ...) \
+  record_value("WARNING\n" str_ "\n", ##__VA_ARGS__)
+
+static void record_flush() {
+  if (!test_buf) {
+    return;
+  }
+  MOZ_UNUSED(write(output_pipe, test_buf, test_length));
+  if (enable_logging) {
+    MOZ_UNUSED(write(LOG_PIPE, test_buf, test_length));
+  }
+  free(test_buf);
+  test_buf = nullptr;
+}
+
+#endif /* WIDGET_GTK_GFXINFO_h__ */
diff --git a/widget/gtk/GtkCompositorWidget.cpp b/widget/gtk/GtkCompositorWidget.cpp
new file mode 100644
index 0000000000..a3443b9828
--- /dev/null
+++ b/widget/gtk/GtkCompositorWidget.cpp
@@ -0,0 +1,247 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GtkCompositorWidget.h"
+
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/layers/CompositorThread.h"
+#include "mozilla/widget/InProcessCompositorWidget.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "nsWindow.h"
+
+#ifdef MOZ_X11
+#  include "mozilla/X11Util.h"
+#endif
+
+#ifdef MOZ_WAYLAND
+#  include "mozilla/layers/NativeLayerWayland.h"
+#endif
+
+#ifdef MOZ_LOGGING
+#  undef LOG
+#  define LOG(str, ...)                               \
+    MOZ_LOG(IsPopup() ? gWidgetPopupLog : gWidgetLog, \
+            mozilla::LogLevel::Debug,                 \
+            ("[%p]: " str, mWidget.get(), ##__VA_ARGS__))
+#endif /* MOZ_LOGGING */
+
+namespace mozilla {
+namespace widget {
+
+GtkCompositorWidget::GtkCompositorWidget(
+    const GtkCompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions, RefPtr<nsWindow> aWindow)
+    : CompositorWidget(aOptions),
+      mWidget(std::move(aWindow)),
+      mClientSize(LayoutDeviceIntSize(aInitData.InitialClientSize()),
+                  "GtkCompositorWidget::mClientSize") {
+#if defined(MOZ_X11)
+  if (GdkIsX11Display()) {
+    mXWindow = (Window)aInitData.XWindow();
+    ConfigureX11Backend(mXWindow, aInitData.Shaped());
+    LOG("GtkCompositorWidget::GtkCompositorWidget() [%p] mXWindow %p "
+        "mIsRenderingSuspended %d\n",
+        (void*)mWidget.get(), (void*)mXWindow, !!mIsRenderingSuspended);
+  }
+#endif
+#if defined(MOZ_WAYLAND)
+  if (GdkIsWaylandDisplay()) {
+    ConfigureWaylandBackend();
+    LOG("GtkCompositorWidget::GtkCompositorWidget() [%p] mWidget %p "
+        "mIsRenderingSuspended %d\n",
+        (void*)mWidget.get(), (void*)mWidget, !!mIsRenderingSuspended);
+  }
+#endif
+}
+
+GtkCompositorWidget::~GtkCompositorWidget() {
+  LOG("GtkCompositorWidget::~GtkCompositorWidget [%p]\n", (void*)mWidget.get());
+  DisableRendering();
+  RefPtr<nsIWidget> widget = mWidget.forget();
+  NS_ReleaseOnMainThread("GtkCompositorWidget::mWidget", widget.forget());
+}
+
+already_AddRefed<gfx::DrawTarget> GtkCompositorWidget::StartRemoteDrawing() {
+  return nullptr;
+}
+void GtkCompositorWidget::EndRemoteDrawing() {}
+
+already_AddRefed<gfx::DrawTarget>
+GtkCompositorWidget::StartRemoteDrawingInRegion(
+    const LayoutDeviceIntRegion& aInvalidRegion,
+    layers::BufferMode* aBufferMode) {
+  return mProvider.StartRemoteDrawingInRegion(aInvalidRegion, aBufferMode);
+}
+
+void GtkCompositorWidget::EndRemoteDrawingInRegion(
+    gfx::DrawTarget* aDrawTarget, const LayoutDeviceIntRegion& aInvalidRegion) {
+  mProvider.EndRemoteDrawingInRegion(aDrawTarget, aInvalidRegion);
+}
+
+nsIWidget* GtkCompositorWidget::RealWidget() { return mWidget; }
+
+void GtkCompositorWidget::NotifyClientSizeChanged(
+    const LayoutDeviceIntSize& aClientSize) {
+  LOG("GtkCompositorWidget::NotifyClientSizeChanged() to %d x %d",
+      aClientSize.width, aClientSize.height);
+
+  auto size = mClientSize.Lock();
+  *size = aClientSize;
+}
+
+LayoutDeviceIntSize GtkCompositorWidget::GetClientSize() {
+  auto size = mClientSize.Lock();
+  return *size;
+}
+
+void GtkCompositorWidget::RemoteLayoutSizeUpdated(
+    const LayoutDeviceRect& aSize) {
+  if (!mWidget || !mWidget->IsWaitingForCompositorResume()) {
+    return;
+  }
+
+  LOG("GtkCompositorWidget::RemoteLayoutSizeUpdated() %d x %d",
+      (int)aSize.width, (int)aSize.height);
+
+  // We're waiting for layout to match widget size.
+  auto clientSize = mClientSize.Lock();
+  if (clientSize->width != (int)aSize.width ||
+      clientSize->height != (int)aSize.height) {
+    LOG("quit, client size doesn't match (%d x %d)", clientSize->width,
+        clientSize->height);
+    return;
+  }
+
+  mWidget->ResumeCompositorFromCompositorThread();
+}
+
+EGLNativeWindowType GtkCompositorWidget::GetEGLNativeWindow() {
+  EGLNativeWindowType window = nullptr;
+  if (mWidget) {
+    window = (EGLNativeWindowType)mWidget->GetNativeData(NS_NATIVE_EGL_WINDOW);
+  }
+#if defined(MOZ_X11)
+  if (mXWindow) {
+    window = (EGLNativeWindowType)mXWindow;
+  }
+#endif
+  LOG("GtkCompositorWidget::GetEGLNativeWindow [%p] window %p\n", mWidget.get(),
+      window);
+  return window;
+}
+
+bool GtkCompositorWidget::SetEGLNativeWindowSize(
+    const LayoutDeviceIntSize& aEGLWindowSize) {
+#if defined(MOZ_WAYLAND)
+  if (mWidget) {
+    return mWidget->SetEGLNativeWindowSize(aEGLWindowSize);
+  }
+#endif
+  return true;
+}
+
+LayoutDeviceIntRegion GtkCompositorWidget::GetTransparentRegion() {
+  // We need to clear target buffer alpha values of popup windows as
+  // SW-WR paints with alpha blending (see Bug 1674473).
+  if (!mWidget || mWidget->IsPopup()) {
+    return LayoutDeviceIntRect(LayoutDeviceIntPoint(0, 0), GetClientSize());
+  }
+
+  // Clear background of titlebar area to render titlebar
+  // transparent corners correctly.
+  return mWidget->GetTitlebarRect();
+}
+
+#ifdef MOZ_WAYLAND
+RefPtr<mozilla::layers::NativeLayerRoot>
+GtkCompositorWidget::GetNativeLayerRoot() {
+  if (gfx::gfxVars::UseWebRenderCompositor()) {
+    if (!mNativeLayerRoot) {
+      MOZ_ASSERT(mWidget && mWidget->GetMozContainer());
+      mNativeLayerRoot = NativeLayerRootWayland::CreateForMozContainer(
+          mWidget->GetMozContainer());
+    }
+    return mNativeLayerRoot;
+  }
+  return nullptr;
+}
+#endif
+
+void GtkCompositorWidget::DisableRendering() {
+  LOG("GtkCompositorWidget::DisableRendering [%p]\n", (void*)mWidget.get());
+  mIsRenderingSuspended = true;
+  mProvider.CleanupResources();
+#if defined(MOZ_X11)
+  mXWindow = {};
+#endif
+}
+
+#if defined(MOZ_WAYLAND)
+bool GtkCompositorWidget::ConfigureWaylandBackend() {
+  mProvider.Initialize(this);
+  return true;
+}
+#endif
+
+#if defined(MOZ_X11)
+bool GtkCompositorWidget::ConfigureX11Backend(Window aXWindow, bool aShaped) {
+  mXWindow = aXWindow;
+
+  // We don't have X window yet.
+  if (!mXWindow) {
+    mIsRenderingSuspended = true;
+    return false;
+  }
+
+  // Grab the window's visual and depth
+  XWindowAttributes windowAttrs;
+  if (!XGetWindowAttributes(DefaultXDisplay(), mXWindow, &windowAttrs)) {
+    NS_WARNING("GtkCompositorWidget(): XGetWindowAttributes() failed!");
+    return false;
+  }
+
+  Visual* visual = windowAttrs.visual;
+  int depth = windowAttrs.depth;
+
+  // Initialize the window surface provider
+  mProvider.Initialize(mXWindow, visual, depth, aShaped);
+  return true;
+}
+#endif
+
+void GtkCompositorWidget::EnableRendering(const uintptr_t aXWindow,
+                                          const bool aShaped) {
+  LOG("GtkCompositorWidget::EnableRendering() [%p]\n", mWidget.get());
+
+  if (!mIsRenderingSuspended) {
+    LOG("  quit, mIsRenderingSuspended = false\n");
+    return;
+  }
+#if defined(MOZ_WAYLAND)
+  if (GdkIsWaylandDisplay()) {
+    LOG("  configure widget %p\n", mWidget.get());
+    if (!ConfigureWaylandBackend()) {
+      return;
+    }
+  }
+#endif
+#if defined(MOZ_X11)
+  if (GdkIsX11Display()) {
+    LOG("  configure XWindow %p shaped %d\n", (void*)aXWindow, aShaped);
+    if (!ConfigureX11Backend((Window)aXWindow, aShaped)) {
+      return;
+    }
+  }
+#endif
+  mIsRenderingSuspended = false;
+}
+#ifdef MOZ_LOGGING
+bool GtkCompositorWidget::IsPopup() {
+  return mWidget ? mWidget->IsPopup() : false;
+}
+#endif
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/gtk/GtkCompositorWidget.h b/widget/gtk/GtkCompositorWidget.h
new file mode 100644
index 0000000000..5bf89835d7
--- /dev/null
+++ b/widget/gtk/GtkCompositorWidget.h
@@ -0,0 +1,140 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_gtk_GtkCompositorWidget_h
+#define widget_gtk_GtkCompositorWidget_h
+
+#include "GLDefs.h"
+#include "mozilla/DataMutex.h"
+#include "mozilla/widget/CompositorWidget.h"
+#include "WindowSurfaceProvider.h"
+
+class nsIWidget;
+class nsWindow;
+
+namespace mozilla {
+
+namespace layers {
+class NativeLayerRootWayland;
+}  // namespace layers
+
+namespace widget {
+
+class PlatformCompositorWidgetDelegate : public CompositorWidgetDelegate {
+ public:
+  virtual void NotifyClientSizeChanged(
+      const LayoutDeviceIntSize& aClientSize) = 0;
+  virtual GtkCompositorWidget* AsGtkCompositorWidget() { return nullptr; };
+
+  virtual void DisableRendering() = 0;
+  virtual void EnableRendering(const uintptr_t aXWindow,
+                               const bool aShaped) = 0;
+
+  // CompositorWidgetDelegate Overrides
+
+  PlatformCompositorWidgetDelegate* AsPlatformSpecificDelegate() override {
+    return this;
+  }
+};
+
+class GtkCompositorWidgetInitData;
+
+class GtkCompositorWidget : public CompositorWidget,
+                            public PlatformCompositorWidgetDelegate {
+ public:
+  GtkCompositorWidget(const GtkCompositorWidgetInitData& aInitData,
+                      const layers::CompositorOptions& aOptions,
+                      RefPtr<nsWindow> aWindow /* = nullptr*/);
+  ~GtkCompositorWidget();
+
+  // CompositorWidget Overrides
+
+  already_AddRefed<gfx::DrawTarget> StartRemoteDrawing() override;
+  void EndRemoteDrawing() override;
+
+  already_AddRefed<gfx::DrawTarget> StartRemoteDrawingInRegion(
+      const LayoutDeviceIntRegion& aInvalidRegion,
+      layers::BufferMode* aBufferMode) override;
+  void EndRemoteDrawingInRegion(
+      gfx::DrawTarget* aDrawTarget,
+      const LayoutDeviceIntRegion& aInvalidRegion) override;
+
+  LayoutDeviceIntSize GetClientSize() override;
+  void RemoteLayoutSizeUpdated(const LayoutDeviceRect& aSize);
+
+  nsIWidget* RealWidget() override;
+  GtkCompositorWidget* AsGTK() override { return this; }
+  CompositorWidgetDelegate* AsDelegate() override { return this; }
+
+  EGLNativeWindowType GetEGLNativeWindow();
+
+  LayoutDeviceIntRegion GetTransparentRegion() override;
+
+  // Suspend rendering of this remote widget and clear all resources.
+  // Can be used when underlying window is hidden/unmapped.
+  void DisableRendering() override;
+
+  // Resume rendering with to given aXWindow (X11) or nsWindow (Wayland).
+  void EnableRendering(const uintptr_t aXWindow, const bool aShaped) override;
+
+  // If we fail to set window size (due to different screen scale or so)
+  // we can't paint the frame by compositor.
+  bool SetEGLNativeWindowSize(const LayoutDeviceIntSize& aEGLWindowSize);
+
+#if defined(MOZ_X11)
+  Window XWindow() const { return mXWindow; }
+#endif
+#if defined(MOZ_WAYLAND)
+  RefPtr<mozilla::layers::NativeLayerRoot> GetNativeLayerRoot() override;
+#endif
+
+  bool PreRender(WidgetRenderingContext* aContext) override {
+    return !mIsRenderingSuspended;
+  }
+  bool IsHidden() const override { return mIsRenderingSuspended; }
+
+  // PlatformCompositorWidgetDelegate Overrides
+
+  void NotifyClientSizeChanged(const LayoutDeviceIntSize& aClientSize) override;
+  GtkCompositorWidget* AsGtkCompositorWidget() override { return this; }
+
+ private:
+#if defined(MOZ_WAYLAND)
+  bool ConfigureWaylandBackend();
+#endif
+#if defined(MOZ_X11)
+  bool ConfigureX11Backend(Window aXWindow, bool aShaped);
+#endif
+#ifdef MOZ_LOGGING
+  bool IsPopup();
+#endif
+
+ protected:
+  RefPtr<nsWindow> mWidget;
+
+ private:
+  // This field is written to on the main thread and read from on the compositor
+  // or renderer thread. During window resizing, this is subject to a (largely
+  // benign) read/write race, see bug 1665726. The DataMutex doesn't prevent the
+  // read/write race, but it does make it Not Undefined Behaviour, and also
+  // ensures we only ever use the old or new size, and not some weird synthesis
+  // of the two.
+  DataMutex<LayoutDeviceIntSize> mClientSize;
+
+  WindowSurfaceProvider mProvider;
+
+#if defined(MOZ_X11)
+  Window mXWindow = {};
+#endif
+#ifdef MOZ_WAYLAND
+  RefPtr<mozilla::layers::NativeLayerRootWayland> mNativeLayerRoot;
+#endif
+  Atomic<bool> mIsRenderingSuspended{true};
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_gtk_GtkCompositorWidget_h
diff --git a/widget/gtk/IMContextWrapper.cpp b/widget/gtk/IMContextWrapper.cpp
new file mode 100644
index 0000000000..fc87acbf86
--- /dev/null
+++ b/widget/gtk/IMContextWrapper.cpp
@@ -0,0 +1,3358 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=4 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Logging.h"
+#include "nsString.h"
+#include "prtime.h"
+#include "prenv.h"
+
+#include "IMContextWrapper.h"
+
+#include "GRefPtr.h"
+#include "nsGtkKeyUtils.h"
+#include "nsWindow.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/Likely.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_intl.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/ToString.h"
+#include "mozilla/WritingModes.h"
+
+// For collecting other people's log, tell `MOZ_LOG=IMEHandler:4,sync`
+// rather than `MOZ_LOG=IMEHandler:5,sync` since using `5` may create too
+// big file.
+// Therefore you shouldn't use `LogLevel::Verbose` for logging usual behavior.
+mozilla::LazyLogModule gIMELog("IMEHandler");
+
+namespace mozilla {
+namespace widget {
+
+static inline const char* ToChar(bool aBool) {
+  return aBool ? "true" : "false";
+}
+
+static const char* GetEventType(GdkEventKey* aKeyEvent) {
+  switch (aKeyEvent->type) {
+    case GDK_KEY_PRESS:
+      return "GDK_KEY_PRESS";
+    case GDK_KEY_RELEASE:
+      return "GDK_KEY_RELEASE";
+    default:
+      return "Unknown";
+  }
+}
+
+class GetEventStateName : public nsAutoCString {
+ public:
+  explicit GetEventStateName(guint aState,
+                             IMContextWrapper::IMContextID aIMContextID =
+                                 IMContextWrapper::IMContextID::Unknown) {
+    if (aState & GDK_SHIFT_MASK) {
+      AppendModifier("shift");
+    }
+    if (aState & GDK_CONTROL_MASK) {
+      AppendModifier("control");
+    }
+    if (aState & GDK_MOD1_MASK) {
+      AppendModifier("mod1");
+    }
+    if (aState & GDK_MOD2_MASK) {
+      AppendModifier("mod2");
+    }
+    if (aState & GDK_MOD3_MASK) {
+      AppendModifier("mod3");
+    }
+    if (aState & GDK_MOD4_MASK) {
+      AppendModifier("mod4");
+    }
+    if (aState & GDK_MOD4_MASK) {
+      AppendModifier("mod5");
+    }
+    if (aState & GDK_MOD4_MASK) {
+      AppendModifier("mod5");
+    }
+    switch (aIMContextID) {
+      case IMContextWrapper::IMContextID::IBus:
+        static const guint IBUS_HANDLED_MASK = 1 << 24;
+        static const guint IBUS_IGNORED_MASK = 1 << 25;
+        if (aState & IBUS_HANDLED_MASK) {
+          AppendModifier("IBUS_HANDLED_MASK");
+        }
+        if (aState & IBUS_IGNORED_MASK) {
+          AppendModifier("IBUS_IGNORED_MASK");
+        }
+        break;
+      case IMContextWrapper::IMContextID::Fcitx:
+      case IMContextWrapper::IMContextID::Fcitx5:
+        static const guint FcitxKeyState_HandledMask = 1 << 24;
+        static const guint FcitxKeyState_IgnoredMask = 1 << 25;
+        if (aState & FcitxKeyState_HandledMask) {
+          AppendModifier("FcitxKeyState_HandledMask");
+        }
+        if (aState & FcitxKeyState_IgnoredMask) {
+          AppendModifier("FcitxKeyState_IgnoredMask");
+        }
+        break;
+      default:
+        break;
+    }
+  }
+
+ private:
+  void AppendModifier(const char* aModifierName) {
+    if (!IsEmpty()) {
+      AppendLiteral(" + ");
+    }
+    Append(aModifierName);
+  }
+};
+
+class GetTextRangeStyleText final : public nsAutoCString {
+ public:
+  explicit GetTextRangeStyleText(const TextRangeStyle& aStyle) {
+    if (!aStyle.IsDefined()) {
+      AssignLiteral("{ IsDefined()=false }");
+      return;
+    }
+
+    if (aStyle.IsLineStyleDefined()) {
+      AppendLiteral("{ mLineStyle=");
+      AppendLineStyle(aStyle.mLineStyle);
+      if (aStyle.IsUnderlineColorDefined()) {
+        AppendLiteral(", mUnderlineColor=");
+        AppendColor(aStyle.mUnderlineColor);
+      } else {
+        AppendLiteral(", IsUnderlineColorDefined=false");
+      }
+    } else {
+      AppendLiteral("{ IsLineStyleDefined()=false");
+    }
+
+    if (aStyle.IsForegroundColorDefined()) {
+      AppendLiteral(", mForegroundColor=");
+      AppendColor(aStyle.mForegroundColor);
+    } else {
+      AppendLiteral(", IsForegroundColorDefined()=false");
+    }
+
+    if (aStyle.IsBackgroundColorDefined()) {
+      AppendLiteral(", mBackgroundColor=");
+      AppendColor(aStyle.mBackgroundColor);
+    } else {
+      AppendLiteral(", IsBackgroundColorDefined()=false");
+    }
+
+    AppendLiteral(" }");
+  }
+  void AppendLineStyle(TextRangeStyle::LineStyle aLineStyle) {
+    switch (aLineStyle) {
+      case TextRangeStyle::LineStyle::None:
+        AppendLiteral("LineStyle::None");
+        break;
+      case TextRangeStyle::LineStyle::Solid:
+        AppendLiteral("LineStyle::Solid");
+        break;
+      case TextRangeStyle::LineStyle::Dotted:
+        AppendLiteral("LineStyle::Dotted");
+        break;
+      case TextRangeStyle::LineStyle::Dashed:
+        AppendLiteral("LineStyle::Dashed");
+        break;
+      case TextRangeStyle::LineStyle::Double:
+        AppendLiteral("LineStyle::Double");
+        break;
+      case TextRangeStyle::LineStyle::Wavy:
+        AppendLiteral("LineStyle::Wavy");
+        break;
+      default:
+        AppendPrintf("Invalid(0x%02X)",
+                     static_cast<TextRangeStyle::LineStyleType>(aLineStyle));
+        break;
+    }
+  }
+  void AppendColor(nscolor aColor) {
+    AppendPrintf("{ R=0x%02X, G=0x%02X, B=0x%02X, A=0x%02X }", NS_GET_R(aColor),
+                 NS_GET_G(aColor), NS_GET_B(aColor), NS_GET_A(aColor));
+  }
+  virtual ~GetTextRangeStyleText() = default;
+};
+
+const static bool kUseSimpleContextDefault = false;
+
+/******************************************************************************
+ * SelectionStyleProvider
+ *
+ * IME (e.g., fcitx, ~4.2.8.3) may look up selection colors of widget, which
+ * is related to the window associated with the IM context, to support any
+ * colored widgets.  Our editor (like <input type="text">) is rendered as
+ * native GtkTextView as far as possible by default and if editor color is
+ * changed by web apps, nsTextFrame may swap background color of foreground
+ * color of composition string for making composition string is always
+ * visually distinct in normal text.
+ *
+ * So, we would like IME to set style of composition string to good colors
+ * in GtkTextView.  Therefore, this class overwrites selection colors of
+ * our widget with selection colors of GtkTextView so that it's possible IME
+ * to refer selection colors of GtkTextView via our widget.
+ ******************************************************************************/
+
+static Maybe<nscolor> GetSystemColor(LookAndFeel::ColorID aId) {
+  return LookAndFeel::GetColor(aId, LookAndFeel::ColorScheme::Light,
+                               LookAndFeel::UseStandins::No);
+}
+
+class SelectionStyleProvider final {
+ public:
+  static SelectionStyleProvider* GetExistingInstance() { return sInstance; }
+
+  static SelectionStyleProvider* GetInstance() {
+    if (sHasShutDown) {
+      return nullptr;
+    }
+    if (!sInstance) {
+      sInstance = new SelectionStyleProvider();
+    }
+    return sInstance;
+  }
+
+  static void Shutdown() {
+    if (sInstance) {
+      g_object_unref(sInstance->mProvider);
+    }
+    delete sInstance;
+    sInstance = nullptr;
+    sHasShutDown = true;
+  }
+
+  // mContainer associated with an IM context.
+  void AttachTo(MozContainer* aContainer) {
+    gtk_style_context_add_provider(
+        gtk_widget_get_style_context(GTK_WIDGET(aContainer)),
+        GTK_STYLE_PROVIDER(mProvider), GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+  }
+
+  void OnThemeChanged() {
+    // fcitx refers GtkStyle::text[GTK_STATE_SELECTED] and
+    // GtkStyle::bg[GTK_STATE_SELECTED] (although pair of text and *base*
+    // or *fg* and bg is correct).  gtk_style_update_from_context() will
+    // set these colors using the widget's GtkStyleContext and so the
+    // colors can be controlled by a ":selected" CSS rule.
+    nsAutoCString style(":selected{");
+    // FYI: LookAndFeel always returns selection colors of GtkTextView.
+    if (auto selectionForegroundColor =
+            GetSystemColor(LookAndFeel::ColorID::Highlight)) {
+      double alpha =
+          static_cast<double>(NS_GET_A(*selectionForegroundColor)) / 0xFF;
+      style.AppendPrintf("color:rgba(%u,%u,%u,",
+                         NS_GET_R(*selectionForegroundColor),
+                         NS_GET_G(*selectionForegroundColor),
+                         NS_GET_B(*selectionForegroundColor));
+      // We can't use AppendPrintf here, because it does locale-specific
+      // formatting of floating-point values.
+      style.AppendFloat(alpha);
+      style.AppendPrintf(");");
+    }
+    if (auto selectionBackgroundColor =
+            GetSystemColor(LookAndFeel::ColorID::Highlighttext)) {
+      double alpha =
+          static_cast<double>(NS_GET_A(*selectionBackgroundColor)) / 0xFF;
+      style.AppendPrintf("background-color:rgba(%u,%u,%u,",
+                         NS_GET_R(*selectionBackgroundColor),
+                         NS_GET_G(*selectionBackgroundColor),
+                         NS_GET_B(*selectionBackgroundColor));
+      style.AppendFloat(alpha);
+      style.AppendPrintf(");");
+    }
+    style.AppendLiteral("}");
+    gtk_css_provider_load_from_data(mProvider, style.get(), -1, nullptr);
+  }
+
+ private:
+  static SelectionStyleProvider* sInstance;
+  static bool sHasShutDown;
+  GtkCssProvider* const mProvider;
+
+  SelectionStyleProvider() : mProvider(gtk_css_provider_new()) {
+    OnThemeChanged();
+  }
+};
+
+SelectionStyleProvider* SelectionStyleProvider::sInstance = nullptr;
+bool SelectionStyleProvider::sHasShutDown = false;
+
+/******************************************************************************
+ * IMContextWrapper
+ ******************************************************************************/
+
+IMContextWrapper* IMContextWrapper::sLastFocusedContext = nullptr;
+guint16 IMContextWrapper::sWaitingSynthesizedKeyPressHardwareKeyCode = 0;
+bool IMContextWrapper::sUseSimpleContext;
+
+NS_IMPL_ISUPPORTS(IMContextWrapper, TextEventDispatcherListener,
+                  nsISupportsWeakReference)
+
+IMContextWrapper::IMContextWrapper(nsWindow* aOwnerWindow)
+    : mOwnerWindow(aOwnerWindow),
+      mLastFocusedWindow(nullptr),
+      mContext(nullptr),
+      mSimpleContext(nullptr),
+      mDummyContext(nullptr),
+      mComposingContext(nullptr),
+      mCompositionStart(UINT32_MAX),
+      mProcessingKeyEvent(nullptr),
+      mCompositionState(eCompositionState_NotComposing),
+      mIMContextID(IMContextID::Unknown),
+      mFallbackToKeyEvent(false),
+      mKeyboardEventWasDispatched(false),
+      mKeyboardEventWasConsumed(false),
+      mIsDeletingSurrounding(false),
+      mLayoutChanged(false),
+      mSetCursorPositionOnKeyEvent(true),
+      mPendingResettingIMContext(false),
+      mRetrieveSurroundingSignalReceived(false),
+      mMaybeInDeadKeySequence(false),
+      mIsIMInAsyncKeyHandlingMode(false),
+      mSetInputPurposeAndInputHints(false) {
+  static bool sFirstInstance = true;
+  if (sFirstInstance) {
+    sFirstInstance = false;
+    sUseSimpleContext =
+        Preferences::GetBool("intl.ime.use_simple_context_on_password_field",
+                             kUseSimpleContextDefault);
+  }
+  Init();
+}
+
+static bool IsIBusInSyncMode() {
+  // See ibus_im_context_class_init() in client/gtk2/ibusimcontext.c
+  // https://github.com/ibus/ibus/blob/86963f2f94d1e4fc213b01c2bc2ba9dcf4b22219/client/gtk2/ibusimcontext.c#L610
+  const char* env = PR_GetEnv("IBUS_ENABLE_SYNC_MODE");
+
+  // See _get_boolean_env() in client/gtk2/ibusimcontext.c
+  // https://github.com/ibus/ibus/blob/86963f2f94d1e4fc213b01c2bc2ba9dcf4b22219/client/gtk2/ibusimcontext.c#L520-L537
+  if (!env) {
+    return false;
+  }
+  nsDependentCString envStr(env);
+  if (envStr.IsEmpty() || envStr.EqualsLiteral("0") ||
+      envStr.EqualsLiteral("false") || envStr.EqualsLiteral("False") ||
+      envStr.EqualsLiteral("FALSE")) {
+    return false;
+  }
+  return true;
+}
+
+static bool GetFcitxBoolEnv(const char* aEnv) {
+  // See fcitx_utils_get_boolean_env in src/lib/fcitx-utils/utils.c
+  // https://github.com/fcitx/fcitx/blob/0c87840dc7d9460c2cb5feaeefec299d0d3d62ec/src/lib/fcitx-utils/utils.c#L721-L736
+  const char* env = PR_GetEnv(aEnv);
+  if (!env) {
+    return false;
+  }
+  nsDependentCString envStr(env);
+  if (envStr.IsEmpty() || envStr.EqualsLiteral("0") ||
+      envStr.EqualsLiteral("false")) {
+    return false;
+  }
+  return true;
+}
+
+static bool IsFcitxInSyncMode() {
+  // See fcitx_im_context_class_init() in src/frontend/gtk2/fcitximcontext.c
+  // https://github.com/fcitx/fcitx/blob/78b98d9230dc9630e99d52e3172bdf440ffd08c4/src/frontend/gtk2/fcitximcontext.c#L395-L398
+  return GetFcitxBoolEnv("IBUS_ENABLE_SYNC_MODE") ||
+         GetFcitxBoolEnv("FCITX_ENABLE_SYNC_MODE");
+}
+
+nsDependentCSubstring IMContextWrapper::GetIMName() const {
+  const char* contextIDChar =
+      gtk_im_multicontext_get_context_id(GTK_IM_MULTICONTEXT(mContext));
+  if (!contextIDChar) {
+    return nsDependentCSubstring();
+  }
+
+  nsDependentCSubstring im(contextIDChar, strlen(contextIDChar));
+
+  // If the context is XIM, actual engine must be specified with
+  // |XMODIFIERS=@im=foo|.
+  const char* xmodifiersChar = PR_GetEnv("XMODIFIERS");
+  if (!xmodifiersChar || !im.EqualsLiteral("xim")) {
+    return im;
+  }
+
+  nsDependentCString xmodifiers(xmodifiersChar);
+  int32_t atIMValueStart = xmodifiers.Find("@im=") + 4;
+  if (atIMValueStart < 4 ||
+      xmodifiers.Length() <= static_cast<size_t>(atIMValueStart)) {
+    return im;
+  }
+
+  int32_t atIMValueEnd = xmodifiers.Find("@", atIMValueStart);
+  if (atIMValueEnd > atIMValueStart) {
+    return nsDependentCSubstring(xmodifiersChar + atIMValueStart,
+                                 atIMValueEnd - atIMValueStart);
+  }
+
+  if (atIMValueEnd == kNotFound) {
+    return nsDependentCSubstring(xmodifiersChar + atIMValueStart,
+                                 strlen(xmodifiersChar) - atIMValueStart);
+  }
+
+  return im;
+}
+
+void IMContextWrapper::Init() {
+  // Overwrite selection colors of the window before associating the window
+  // with IM context since IME may look up selection colors via IM context
+  // to support any colored widgets.
+  SelectionStyleProvider::GetInstance()->AttachTo(
+      mOwnerWindow->GetMozContainer());
+
+  // NOTE: gtk_im_*_new() abort (kill) the whole process when it fails.
+  //       So, we don't need to check the result.
+
+  // Normal context.
+  mContext = gtk_im_multicontext_new();
+  g_signal_connect(mContext, "preedit_changed",
+                   G_CALLBACK(IMContextWrapper::OnChangeCompositionCallback),
+                   this);
+  g_signal_connect(mContext, "retrieve_surrounding",
+                   G_CALLBACK(IMContextWrapper::OnRetrieveSurroundingCallback),
+                   this);
+  g_signal_connect(mContext, "delete_surrounding",
+                   G_CALLBACK(IMContextWrapper::OnDeleteSurroundingCallback),
+                   this);
+  g_signal_connect(mContext, "commit",
+                   G_CALLBACK(IMContextWrapper::OnCommitCompositionCallback),
+                   this);
+  g_signal_connect(mContext, "preedit_start",
+                   G_CALLBACK(IMContextWrapper::OnStartCompositionCallback),
+                   this);
+  g_signal_connect(mContext, "preedit_end",
+                   G_CALLBACK(IMContextWrapper::OnEndCompositionCallback),
+                   this);
+  nsDependentCSubstring im = GetIMName();
+  if (im.EqualsLiteral("ibus")) {
+    mIMContextID = IMContextID::IBus;
+    mIsIMInAsyncKeyHandlingMode = !IsIBusInSyncMode();
+    // Although ibus has key snooper mode, it's forcibly disabled on Firefox
+    // in default settings by its whitelist since we always send key events
+    // to IME before handling shortcut keys.  The whitelist can be
+    // customized with env, IBUS_NO_SNOOPER_APPS, but we don't need to
+    // support such rare cases for reducing maintenance cost.
+    mIsKeySnooped = false;
+  } else if (im.EqualsLiteral("fcitx")) {
+    mIMContextID = IMContextID::Fcitx;
+    mIsIMInAsyncKeyHandlingMode = !IsFcitxInSyncMode();
+    // Although Fcitx has key snooper mode similar to ibus, it's also
+    // disabled on Firefox in default settings by its whitelist.  The
+    // whitelist can be customized with env, IBUS_NO_SNOOPER_APPS or
+    // FCITX_NO_SNOOPER_APPS, but we don't need to support such rare cases
+    // for reducing maintenance cost.
+    mIsKeySnooped = false;
+  } else if (im.EqualsLiteral("fcitx5")) {
+    mIMContextID = IMContextID::Fcitx5;
+    mIsIMInAsyncKeyHandlingMode = true;  // does not have sync mode.
+    mIsKeySnooped = false;               // never use key snooper.
+  } else if (im.EqualsLiteral("uim")) {
+    mIMContextID = IMContextID::Uim;
+    mIsIMInAsyncKeyHandlingMode = false;
+    // We cannot know if uim uses key snooper since it's build option of
+    // uim.  Therefore, we need to retrieve the consideration from the
+    // pref for making users and distributions allowed to choose their
+    // preferred value.
+    mIsKeySnooped =
+        Preferences::GetBool("intl.ime.hack.uim.using_key_snooper", true);
+  } else if (im.EqualsLiteral("scim")) {
+    mIMContextID = IMContextID::Scim;
+    mIsIMInAsyncKeyHandlingMode = false;
+    mIsKeySnooped = false;
+  } else if (im.EqualsLiteral("iiim")) {
+    mIMContextID = IMContextID::IIIMF;
+    mIsIMInAsyncKeyHandlingMode = false;
+    mIsKeySnooped = false;
+  } else if (im.EqualsLiteral("wayland")) {
+    mIMContextID = IMContextID::Wayland;
+    mIsIMInAsyncKeyHandlingMode = false;
+    mIsKeySnooped = true;
+  } else {
+    mIMContextID = IMContextID::Unknown;
+    mIsIMInAsyncKeyHandlingMode = false;
+    mIsKeySnooped = false;
+  }
+
+  // Simple context
+  if (sUseSimpleContext) {
+    mSimpleContext = gtk_im_context_simple_new();
+    g_signal_connect(mSimpleContext, "preedit_changed",
+                     G_CALLBACK(&IMContextWrapper::OnChangeCompositionCallback),
+                     this);
+    g_signal_connect(
+        mSimpleContext, "retrieve_surrounding",
+        G_CALLBACK(&IMContextWrapper::OnRetrieveSurroundingCallback), this);
+    g_signal_connect(mSimpleContext, "delete_surrounding",
+                     G_CALLBACK(&IMContextWrapper::OnDeleteSurroundingCallback),
+                     this);
+    g_signal_connect(mSimpleContext, "commit",
+                     G_CALLBACK(&IMContextWrapper::OnCommitCompositionCallback),
+                     this);
+    g_signal_connect(mSimpleContext, "preedit_start",
+                     G_CALLBACK(IMContextWrapper::OnStartCompositionCallback),
+                     this);
+    g_signal_connect(mSimpleContext, "preedit_end",
+                     G_CALLBACK(IMContextWrapper::OnEndCompositionCallback),
+                     this);
+  }
+
+  // Dummy context
+  mDummyContext = gtk_im_multicontext_new();
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p Init(), mOwnerWindow=%p, mContext=%p (im=\"%s\"), "
+           "mIsIMInAsyncKeyHandlingMode=%s, mIsKeySnooped=%s, "
+           "mSimpleContext=%p, mDummyContext=%p, "
+           "gtk_im_multicontext_get_context_id()=\"%s\", "
+           "PR_GetEnv(\"XMODIFIERS\")=\"%s\"",
+           this, mOwnerWindow, mContext, nsAutoCString(im).get(),
+           ToChar(mIsIMInAsyncKeyHandlingMode), ToChar(mIsKeySnooped),
+           mSimpleContext, mDummyContext,
+           gtk_im_multicontext_get_context_id(GTK_IM_MULTICONTEXT(mContext)),
+           PR_GetEnv("XMODIFIERS")));
+}
+
+/* static */
+void IMContextWrapper::Shutdown() { SelectionStyleProvider::Shutdown(); }
+
+IMContextWrapper::~IMContextWrapper() {
+  MOZ_ASSERT(!mContext);
+  MOZ_ASSERT(!mComposingContext);
+  if (this == sLastFocusedContext) {
+    sLastFocusedContext = nullptr;
+  }
+  MOZ_LOG(gIMELog, LogLevel::Info, ("0x%p ~IMContextWrapper()", this));
+}
+
+void IMContextWrapper::SetGdkWindow(GdkWindow* aGdkWindow) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p GdkWindowChanged(%p)", this, aGdkWindow));
+  MOZ_ASSERT(!aGdkWindow || mOwnerWindow->GetGdkWindow() == aGdkWindow);
+  gtk_im_context_set_client_window(mContext, aGdkWindow);
+  if (mSimpleContext) {
+    gtk_im_context_set_client_window(mSimpleContext, aGdkWindow);
+  }
+  gtk_im_context_set_client_window(mDummyContext, aGdkWindow);
+}
+
+NS_IMETHODIMP
+IMContextWrapper::NotifyIME(TextEventDispatcher* aTextEventDispatcher,
+                            const IMENotification& aNotification) {
+  switch (aNotification.mMessage) {
+    case REQUEST_TO_COMMIT_COMPOSITION:
+    case REQUEST_TO_CANCEL_COMPOSITION: {
+      nsWindow* window =
+          static_cast<nsWindow*>(aTextEventDispatcher->GetWidget());
+      return IsComposing() ? EndIMEComposition(window) : NS_OK;
+    }
+    case NOTIFY_IME_OF_FOCUS:
+      OnFocusChangeInGecko(true);
+      return NS_OK;
+    case NOTIFY_IME_OF_BLUR:
+      OnFocusChangeInGecko(false);
+      return NS_OK;
+    case NOTIFY_IME_OF_POSITION_CHANGE:
+      OnLayoutChange();
+      return NS_OK;
+    case NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED:
+      OnUpdateComposition();
+      return NS_OK;
+    case NOTIFY_IME_OF_SELECTION_CHANGE: {
+      nsWindow* window =
+          static_cast<nsWindow*>(aTextEventDispatcher->GetWidget());
+      OnSelectionChange(window, aNotification);
+      return NS_OK;
+    }
+    default:
+      return NS_ERROR_NOT_IMPLEMENTED;
+  }
+}
+
+NS_IMETHODIMP_(void)
+IMContextWrapper::OnRemovedFrom(TextEventDispatcher* aTextEventDispatcher) {
+  // XXX When input transaction is being stolen by add-on, what should we do?
+}
+
+NS_IMETHODIMP_(void)
+IMContextWrapper::WillDispatchKeyboardEvent(
+    TextEventDispatcher* aTextEventDispatcher,
+    WidgetKeyboardEvent& aKeyboardEvent, uint32_t aIndexOfKeypress,
+    void* aData) {
+  KeymapWrapper::WillDispatchKeyboardEvent(aKeyboardEvent,
+                                           static_cast<GdkEventKey*>(aData));
+}
+
+TextEventDispatcher* IMContextWrapper::GetTextEventDispatcher() {
+  if (NS_WARN_IF(!mLastFocusedWindow)) {
+    return nullptr;
+  }
+  TextEventDispatcher* dispatcher =
+      mLastFocusedWindow->GetTextEventDispatcher();
+  // nsIWidget::GetTextEventDispatcher() shouldn't return nullptr.
+  MOZ_RELEASE_ASSERT(dispatcher);
+  return dispatcher;
+}
+
+NS_IMETHODIMP_(IMENotificationRequests)
+IMContextWrapper::GetIMENotificationRequests() {
+  IMENotificationRequests::Notifications notifications =
+      IMENotificationRequests::NOTIFY_NOTHING;
+  // If it's not enabled, we don't need position change notification.
+  if (IsEnabled()) {
+    notifications |= IMENotificationRequests::NOTIFY_POSITION_CHANGE;
+  }
+  return IMENotificationRequests(notifications);
+}
+
+void IMContextWrapper::OnDestroyWindow(nsWindow* aWindow) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p OnDestroyWindow(aWindow=0x%p), mLastFocusedWindow=0x%p, "
+       "mOwnerWindow=0x%p, mLastFocusedModule=0x%p",
+       this, aWindow, mLastFocusedWindow, mOwnerWindow, sLastFocusedContext));
+
+  MOZ_ASSERT(aWindow, "aWindow must not be null");
+
+  if (mLastFocusedWindow == aWindow) {
+    if (IsComposing()) {
+      EndIMEComposition(aWindow);
+    }
+    NotifyIMEOfFocusChange(IMEFocusState::Blurred);
+    mLastFocusedWindow = nullptr;
+  }
+
+  if (mOwnerWindow != aWindow) {
+    return;
+  }
+
+  if (sLastFocusedContext == this) {
+    sLastFocusedContext = nullptr;
+  }
+
+  /**
+   * NOTE:
+   *   The given window is the owner of this, so, we must disconnect from the
+   *   contexts now.  But that might be referred from other nsWindows
+   *   (they are children of this.  But we don't know why there are the
+   *   cases).  So, we need to clear the pointers that refers to contexts
+   *   and this if the other referrers are still alive. See bug 349727.
+   */
+  if (mContext) {
+    PrepareToDestroyContext(mContext);
+    gtk_im_context_set_client_window(mContext, nullptr);
+    g_signal_handlers_disconnect_by_data(mContext, this);
+    g_object_unref(mContext);
+    mContext = nullptr;
+  }
+
+  if (mSimpleContext) {
+    gtk_im_context_set_client_window(mSimpleContext, nullptr);
+    g_signal_handlers_disconnect_by_data(mSimpleContext, this);
+    g_object_unref(mSimpleContext);
+    mSimpleContext = nullptr;
+  }
+
+  if (mDummyContext) {
+    // mContext and mDummyContext have the same slaveType and signal_data
+    // so no need for another workaround_gtk_im_display_closed.
+    gtk_im_context_set_client_window(mDummyContext, nullptr);
+    g_object_unref(mDummyContext);
+    mDummyContext = nullptr;
+  }
+
+  if (NS_WARN_IF(mComposingContext)) {
+    g_object_unref(mComposingContext);
+    mComposingContext = nullptr;
+  }
+
+  mOwnerWindow = nullptr;
+  mLastFocusedWindow = nullptr;
+  mInputContext.mIMEState.mEnabled = IMEEnabled::Disabled;
+  mPostingKeyEvents.Clear();
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   OnDestroyWindow(), succeeded, Completely destroyed", this));
+}
+
+void IMContextWrapper::PrepareToDestroyContext(GtkIMContext* aContext) {
+  if (mIMContextID == IMContextID::IIIMF) {
+    // IIIM module registers handlers for the "closed" signal on the
+    // display, but the signal handler is not disconnected when the module
+    // is unloaded.  To prevent the module from being unloaded, use static
+    // variable to hold reference of slave context class declared by IIIM.
+    // Note that this does not grab any instance, it grabs the "class".
+    static gpointer sGtkIIIMContextClass = nullptr;
+    if (!sGtkIIIMContextClass) {
+      // We retrieved slave context class with g_type_name() and actual
+      // slave context instance when our widget was GTK2.  That must be
+      // _GtkIMContext::priv::slave in GTK3.  However, _GtkIMContext::priv
+      // is an opacity struct named _GtkIMMulticontextPrivate, i.e., it's
+      // not exposed by GTK3.  Therefore, we cannot access the instance
+      // safely.  So, we need to retrieve the slave context class with
+      // g_type_from_name("GtkIMContextIIIM") directly (anyway, we needed
+      // to compare the class name with "GtkIMContextIIIM").
+      GType IIMContextType = g_type_from_name("GtkIMContextIIIM");
+      if (IIMContextType) {
+        sGtkIIIMContextClass = g_type_class_ref(IIMContextType);
+        MOZ_LOG(gIMELog, LogLevel::Info,
+                ("0x%p PrepareToDestroyContext(), added to reference to "
+                 "GtkIMContextIIIM class to prevent it from being unloaded",
+                 this));
+      } else {
+        MOZ_LOG(gIMELog, LogLevel::Error,
+                ("0x%p PrepareToDestroyContext(), FAILED to prevent the "
+                 "IIIM module from being uploaded",
+                 this));
+      }
+    }
+  }
+}
+
+void IMContextWrapper::OnFocusWindow(nsWindow* aWindow) {
+  if (MOZ_UNLIKELY(IsDestroyed())) {
+    return;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p OnFocusWindow(aWindow=0x%p), mLastFocusedWindow=0x%p", this,
+           aWindow, mLastFocusedWindow));
+  mLastFocusedWindow = aWindow;
+}
+
+void IMContextWrapper::OnBlurWindow(nsWindow* aWindow) {
+  if (MOZ_UNLIKELY(IsDestroyed())) {
+    return;
+  }
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p OnBlurWindow(aWindow=0x%p), mLastFocusedWindow=0x%p, "
+       "mIMEFocusState=%s",
+       this, aWindow, mLastFocusedWindow, ToString(mIMEFocusState).c_str()));
+
+  if (mLastFocusedWindow != aWindow) {
+    return;
+  }
+
+  NotifyIMEOfFocusChange(IMEFocusState::Blurred);
+}
+
+KeyHandlingState IMContextWrapper::OnKeyEvent(
+    nsWindow* aCaller, GdkEventKey* aEvent,
+    bool aKeyboardEventWasDispatched /* = false */) {
+  MOZ_ASSERT(aEvent, "aEvent must be non-null");
+
+  if (!mInputContext.mIMEState.IsEditable() || MOZ_UNLIKELY(IsDestroyed())) {
+    return KeyHandlingState::eNotHandled;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info, (">>>>>>>>>>>>>>>>"));
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p OnKeyEvent(aCaller=0x%p, "
+       "aEvent(0x%p): { type=%s, keyval=%s, unicode=0x%X, state=%s, "
+       "time=%u, hardware_keycode=%u, group=%u }, "
+       "aKeyboardEventWasDispatched=%s)",
+       this, aCaller, aEvent, GetEventType(aEvent),
+       gdk_keyval_name(aEvent->keyval), gdk_keyval_to_unicode(aEvent->keyval),
+       GetEventStateName(aEvent->state, mIMContextID).get(), aEvent->time,
+       aEvent->hardware_keycode, aEvent->group,
+       ToChar(aKeyboardEventWasDispatched)));
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p   OnKeyEvent(), mMaybeInDeadKeySequence=%s, "
+       "mCompositionState=%s, current context=%p, active context=%p, "
+       "mIMContextID=%s, mIsIMInAsyncKeyHandlingMode=%s",
+       this, ToChar(mMaybeInDeadKeySequence), GetCompositionStateName(),
+       GetCurrentContext(), GetActiveContext(), ToString(mIMContextID).c_str(),
+       ToChar(mIsIMInAsyncKeyHandlingMode)));
+
+  if (aCaller != mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   OnKeyEvent(), FAILED, the caller isn't focused "
+             "window, mLastFocusedWindow=0x%p",
+             this, mLastFocusedWindow));
+    return KeyHandlingState::eNotHandled;
+  }
+
+  // Even if old IM context has composition, key event should be sent to
+  // current context since the user expects so.
+  GtkIMContext* currentContext = GetCurrentContext();
+  if (MOZ_UNLIKELY(!currentContext)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   OnKeyEvent(), FAILED, there are no context", this));
+    return KeyHandlingState::eNotHandled;
+  }
+
+  if (mSetCursorPositionOnKeyEvent) {
+    SetCursorPosition(currentContext);
+    mSetCursorPositionOnKeyEvent = false;
+  }
+
+  // Let's support dead key event even if active keyboard layout also
+  // supports complicated composition like CJK IME.
+  bool isDeadKey =
+      KeymapWrapper::ComputeDOMKeyNameIndex(aEvent) == KEY_NAME_INDEX_Dead;
+  mMaybeInDeadKeySequence |= isDeadKey;
+
+  // If current context is mSimpleContext, both ibus and fcitx handles key
+  // events synchronously.  So, only when current context is mContext which
+  // is GtkIMMulticontext, the key event may be handled by IME asynchronously.
+  bool probablyHandledAsynchronously =
+      mIsIMInAsyncKeyHandlingMode && currentContext == mContext;
+
+  // If we're not sure whether the event is handled asynchronously, this is
+  // set to true.
+  bool maybeHandledAsynchronously = false;
+
+  // If aEvent is a synthesized event for async handling, this will be set to
+  // true.
+  bool isHandlingAsyncEvent = false;
+
+  // If we've decided that the event won't be synthesized asyncrhonously
+  // by IME, but actually IME did it, this is set to true.
+  bool isUnexpectedAsyncEvent = false;
+
+  // If IM is ibus or fcitx and it handles key events asynchronously,
+  // they mark aEvent->state as "handled by me" when they post key event
+  // to another process.  Unfortunately, we need to check this hacky
+  // flag because it's difficult to store all pending key events by
+  // an array or a hashtable.
+  if (probablyHandledAsynchronously) {
+    switch (mIMContextID) {
+      case IMContextID::IBus: {
+        // See src/ibustypes.h
+        static const guint IBUS_IGNORED_MASK = 1 << 25;
+        // If IBUS_IGNORED_MASK was set to aEvent->state, the event
+        // has already been handled by another process and it wasn't
+        // used by IME.
+        isHandlingAsyncEvent = !!(aEvent->state & IBUS_IGNORED_MASK);
+        if (!isHandlingAsyncEvent) {
+          // On some environments, IBUS_IGNORED_MASK flag is not set as
+          // expected.  In such case, we keep pusing all events into the queue.
+          // I.e., that causes eating a lot of memory until it's blurred.
+          // Therefore, we need to check whether there is same timestamp event
+          // in the queue.  This redundant cost should be low because in most
+          // causes, key events in the queue should be 2 or 4.
+          isHandlingAsyncEvent =
+              mPostingKeyEvents.IndexOf(aEvent) != GdkEventKeyQueue::NoIndex();
+          if (isHandlingAsyncEvent) {
+            MOZ_LOG(gIMELog, LogLevel::Info,
+                    ("0x%p   OnKeyEvent(), aEvent->state does not have "
+                     "IBUS_IGNORED_MASK but "
+                     "same event in the queue.  So, assuming it's a "
+                     "synthesized event",
+                     this));
+          }
+        }
+
+        // If it's a synthesized event, let's remove it from the posting
+        // event queue first.  Otherwise the following blocks cannot use
+        // `break`.
+        if (isHandlingAsyncEvent) {
+          MOZ_LOG(gIMELog, LogLevel::Info,
+                  ("0x%p   OnKeyEvent(), aEvent->state has IBUS_IGNORED_MASK "
+                   "or aEvent is in the "
+                   "posting event queue, so, it won't be handled "
+                   "asynchronously anymore. Removing "
+                   "the posted events from the queue",
+                   this));
+          probablyHandledAsynchronously = false;
+          mPostingKeyEvents.RemoveEvent(aEvent);
+        }
+
+        // ibus won't send back key press events in a dead key sequcne.
+        if (mMaybeInDeadKeySequence && aEvent->type == GDK_KEY_PRESS) {
+          probablyHandledAsynchronously = false;
+          if (isHandlingAsyncEvent) {
+            isUnexpectedAsyncEvent = true;
+            break;
+          }
+          // Some keyboard layouts which have dead keys may send
+          // "empty" key event to make us call
+          // gtk_im_context_filter_keypress() to commit composed
+          // character during a GDK_KEY_PRESS event dispatching.
+          if (!gdk_keyval_to_unicode(aEvent->keyval) &&
+              !aEvent->hardware_keycode) {
+            isUnexpectedAsyncEvent = true;
+            break;
+          }
+          break;
+        }
+        // ibus may handle key events synchronously if focused editor is
+        // <input type="password"> or |ime-mode: disabled;|.  However, in
+        // some environments, not so actually.  Therefore, we need to check
+        // the result of gtk_im_context_filter_keypress() later.
+        if (mInputContext.mIMEState.mEnabled == IMEEnabled::Password) {
+          probablyHandledAsynchronously = false;
+          maybeHandledAsynchronously = !isHandlingAsyncEvent;
+          break;
+        }
+        break;
+      }
+      case IMContextID::Fcitx:
+      case IMContextID::Fcitx5: {
+        // See src/lib/fcitx-utils/keysym.h
+        static const guint FcitxKeyState_IgnoredMask = 1 << 25;
+        // If FcitxKeyState_IgnoredMask was set to aEvent->state,
+        // the event has already been handled by another process and
+        // it wasn't used by IME.
+        isHandlingAsyncEvent = !!(aEvent->state & FcitxKeyState_IgnoredMask);
+        if (!isHandlingAsyncEvent) {
+          // On some environments, FcitxKeyState_IgnoredMask flag *might* be not
+          // set as expected. If there were such cases, we'd keep pusing all
+          // events into the queue.  I.e., that would cause eating a lot of
+          // memory until it'd be blurred.  Therefore, we should check whether
+          // there is same timestamp event in the queue.  This redundant cost
+          // should be low because in most causes, key events in the queue
+          // should be 2 or 4.
+          isHandlingAsyncEvent =
+              mPostingKeyEvents.IndexOf(aEvent) != GdkEventKeyQueue::NoIndex();
+          if (isHandlingAsyncEvent) {
+            MOZ_LOG(gIMELog, LogLevel::Info,
+                    ("0x%p   OnKeyEvent(), aEvent->state does not have "
+                     "FcitxKeyState_IgnoredMask "
+                     "but same event in the queue.  So, assuming it's a "
+                     "synthesized event",
+                     this));
+          }
+        }
+
+        // fcitx won't send back key press events in a dead key sequcne.
+        if (mMaybeInDeadKeySequence && aEvent->type == GDK_KEY_PRESS) {
+          probablyHandledAsynchronously = false;
+          if (isHandlingAsyncEvent) {
+            isUnexpectedAsyncEvent = true;
+            break;
+          }
+          // Some keyboard layouts which have dead keys may send
+          // "empty" key event to make us call
+          // gtk_im_context_filter_keypress() to commit composed
+          // character during a GDK_KEY_PRESS event dispatching.
+          if (!gdk_keyval_to_unicode(aEvent->keyval) &&
+              !aEvent->hardware_keycode) {
+            isUnexpectedAsyncEvent = true;
+            break;
+          }
+        }
+
+        // fcitx handles key events asynchronously even if focused
+        // editor cannot use IME actually.
+
+        if (isHandlingAsyncEvent) {
+          MOZ_LOG(gIMELog, LogLevel::Info,
+                  ("0x%p   OnKeyEvent(), aEvent->state has "
+                   "FcitxKeyState_IgnoredMask or aEvent is in "
+                   "the posting event queue, so, it won't be handled "
+                   "asynchronously anymore. "
+                   "Removing the posted events from the queue",
+                   this));
+          probablyHandledAsynchronously = false;
+          mPostingKeyEvents.RemoveEvent(aEvent);
+          break;
+        }
+        break;
+      }
+      default:
+        MOZ_ASSERT_UNREACHABLE(
+            "IME may handle key event "
+            "asyncrhonously, but not yet confirmed if it comes agian "
+            "actually");
+    }
+  }
+
+  if (!isUnexpectedAsyncEvent) {
+    mKeyboardEventWasDispatched = aKeyboardEventWasDispatched;
+    mKeyboardEventWasConsumed = false;
+  } else {
+    // If we didn't expect this event, we've alreday dispatched eKeyDown
+    // event or eKeyUp event for that.
+    mKeyboardEventWasDispatched = true;
+    // And in this case, we need to assume that another key event hasn't
+    // been receivied and mKeyboardEventWasConsumed keeps storing the
+    // dispatched eKeyDown or eKeyUp event's state.
+  }
+  mFallbackToKeyEvent = false;
+  mProcessingKeyEvent = aEvent;
+  gboolean isFiltered = gtk_im_context_filter_keypress(currentContext, aEvent);
+
+  // If we're not sure whether the event is handled by IME asynchronously or
+  // synchronously, we need to trust the result of
+  // gtk_im_context_filter_keypress().  If it consumed and but did nothing,
+  // we can assume that another event will be synthesized.
+  if (!isHandlingAsyncEvent && maybeHandledAsynchronously) {
+    probablyHandledAsynchronously |=
+        isFiltered && !mFallbackToKeyEvent && !mKeyboardEventWasDispatched;
+  }
+
+  if (aEvent->type == GDK_KEY_PRESS) {
+    if (isFiltered && probablyHandledAsynchronously) {
+      sWaitingSynthesizedKeyPressHardwareKeyCode = aEvent->hardware_keycode;
+    } else {
+      sWaitingSynthesizedKeyPressHardwareKeyCode = 0;
+    }
+  }
+
+  // The caller of this shouldn't handle aEvent anymore if we've dispatched
+  // composition events or modified content with other events.
+  bool filterThisEvent = isFiltered && !mFallbackToKeyEvent;
+
+  if (IsComposingOnCurrentContext() && !isFiltered &&
+      aEvent->type == GDK_KEY_PRESS && mDispatchedCompositionString.IsEmpty()) {
+    // A Hangul input engine for SCIM doesn't emit preedit_end
+    // signal even when composition string becomes empty.  On the
+    // other hand, we should allow to make composition with empty
+    // string for other languages because there *might* be such
+    // IM.  For compromising this issue, we should dispatch
+    // compositionend event, however, we don't need to reset IM
+    // actually.
+    // NOTE: Don't dispatch key events as "processed by IME" since
+    // we need to dispatch keyboard events as IME wasn't handled it.
+    mProcessingKeyEvent = nullptr;
+    DispatchCompositionCommitEvent(currentContext, &EmptyString());
+    mProcessingKeyEvent = aEvent;
+    // In this case, even though we handle the keyboard event here,
+    // but we should dispatch keydown event as
+    filterThisEvent = false;
+  }
+
+  if (filterThisEvent && !mKeyboardEventWasDispatched) {
+    // If IME handled the key event but we've not dispatched eKeyDown nor
+    // eKeyUp event yet, we need to dispatch here unless the key event is
+    // now being handled by other IME process.
+    if (!probablyHandledAsynchronously) {
+      MaybeDispatchKeyEventAsProcessedByIME(eVoidEvent);
+      // Be aware, the widget might have been gone here.
+    }
+    // If we need to wait reply from IM, IM may send some signals to us
+    // without sending the key event again.  In such case, we need to
+    // dispatch keyboard events with a copy of aEvent.  Therefore, we
+    // need to use information of this key event to dispatch an KeyDown
+    // or eKeyUp event later.
+    else {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   OnKeyEvent(), putting aEvent into the queue...", this));
+      mPostingKeyEvents.PutEvent(aEvent);
+    }
+  }
+
+  mProcessingKeyEvent = nullptr;
+
+  if (aEvent->type == GDK_KEY_PRESS && !filterThisEvent) {
+    // If the key event hasn't been handled by active IME nor keyboard
+    // layout, we can assume that the dead key sequence has been or was
+    // ended.  Note that we should not reset it when the key event is
+    // GDK_KEY_RELEASE since it may not be filtered by active keyboard
+    // layout even in composition.
+    mMaybeInDeadKeySequence = false;
+  }
+
+  if (aEvent->type == GDK_KEY_RELEASE) {
+    if (const GdkEventKey* pendingKeyPressEvent =
+            mPostingKeyEvents.GetCorrespondingKeyPressEvent(aEvent)) {
+      MOZ_LOG(gIMELog, LogLevel::Warning,
+              ("0x%p   OnKeyEvent(), forgetting a pending GDK_KEY_PRESS event "
+               "because GDK_KEY_RELEASE for the event is handled",
+               this));
+      mPostingKeyEvents.RemoveEvent(pendingKeyPressEvent);
+    }
+  }
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Debug,
+      ("0x%p   OnKeyEvent(), succeeded, filterThisEvent=%s "
+       "(isFiltered=%s, mFallbackToKeyEvent=%s, "
+       "probablyHandledAsynchronously=%s, maybeHandledAsynchronously=%s), "
+       "mPostingKeyEvents.Length()=%zu, mCompositionState=%s, "
+       "mMaybeInDeadKeySequence=%s, mKeyboardEventWasDispatched=%s, "
+       "mKeyboardEventWasConsumed=%s",
+       this, ToChar(filterThisEvent), ToChar(isFiltered),
+       ToChar(mFallbackToKeyEvent), ToChar(probablyHandledAsynchronously),
+       ToChar(maybeHandledAsynchronously), mPostingKeyEvents.Length(),
+       GetCompositionStateName(), ToChar(mMaybeInDeadKeySequence),
+       ToChar(mKeyboardEventWasDispatched), ToChar(mKeyboardEventWasConsumed)));
+  MOZ_LOG(gIMELog, LogLevel::Info, ("<<<<<<<<<<<<<<<<\n\n"));
+
+  if (filterThisEvent) {
+    return KeyHandlingState::eHandled;
+  }
+  // If another call of this method has already dispatched eKeyDown event,
+  // we should return KeyHandlingState::eNotHandledButEventDispatched because
+  // the caller should've stopped handling the event if preceding eKeyDown
+  // event was consumed.
+  if (aKeyboardEventWasDispatched) {
+    return KeyHandlingState::eNotHandledButEventDispatched;
+  }
+  if (!mKeyboardEventWasDispatched) {
+    return KeyHandlingState::eNotHandled;
+  }
+  return mKeyboardEventWasConsumed
+             ? KeyHandlingState::eNotHandledButEventConsumed
+             : KeyHandlingState::eNotHandledButEventDispatched;
+}
+
+void IMContextWrapper::OnFocusChangeInGecko(bool aFocus) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p OnFocusChangeInGecko(aFocus=%s),mCompositionState=%s, "
+           "mIMEFocusState=%s, mSetInputPurposeAndInputHints=%s",
+           this, ToChar(aFocus), GetCompositionStateName(),
+           ToString(mIMEFocusState).c_str(),
+           ToChar(mSetInputPurposeAndInputHints)));
+
+  // We shouldn't carry over the removed string to another editor.
+  mSelectedStringRemovedByComposition.Truncate();
+  mContentSelection.reset();
+
+  if (aFocus) {
+    if (mSetInputPurposeAndInputHints) {
+      mSetInputPurposeAndInputHints = false;
+      SetInputPurposeAndInputHints();
+    }
+    NotifyIMEOfFocusChange(IMEFocusState::Focused);
+  } else {
+    NotifyIMEOfFocusChange(IMEFocusState::Blurred);
+  }
+
+  // When the focus changes, we need to inform IM about the new cursor
+  // position. Chinese input methods generally rely on this because they
+  // usually don't start composition until a character is picked.
+  if (aFocus && EnsureToCacheContentSelection()) {
+    SetCursorPosition(GetActiveContext());
+  }
+}
+
+void IMContextWrapper::ResetIME() {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p ResetIME(), mCompositionState=%s, mIMEFocusState=%s", this,
+           GetCompositionStateName(), ToString(mIMEFocusState).c_str()));
+
+  GtkIMContext* activeContext = GetActiveContext();
+  if (MOZ_UNLIKELY(!activeContext)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   ResetIME(), FAILED, there are no context", this));
+    return;
+  }
+
+  RefPtr<IMContextWrapper> kungFuDeathGrip(this);
+  RefPtr<nsWindow> lastFocusedWindow(mLastFocusedWindow);
+
+  mPendingResettingIMContext = false;
+  gtk_im_context_reset(activeContext);
+
+  // The last focused window might have been destroyed by a DOM event handler
+  // which was called by us during a call of gtk_im_context_reset().
+  if (!lastFocusedWindow ||
+      NS_WARN_IF(lastFocusedWindow != mLastFocusedWindow) ||
+      lastFocusedWindow->Destroyed()) {
+    return;
+  }
+
+  nsAutoString compositionString;
+  GetCompositionString(activeContext, compositionString);
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   ResetIME() called gtk_im_context_reset(), "
+           "activeContext=0x%p, mCompositionState=%s, compositionString=%s, "
+           "mIMEFocusState=%s",
+           this, activeContext, GetCompositionStateName(),
+           NS_ConvertUTF16toUTF8(compositionString).get(),
+           ToString(mIMEFocusState).c_str()));
+
+  // XXX IIIMF (ATOK X3 which is one of the Language Engine of it is still
+  //     used in Japan!) sends only "preedit_changed" signal with empty
+  //     composition string synchronously.  Therefore, if composition string
+  //     is now empty string, we should assume that the IME won't send
+  //     "commit" signal.
+  if (IsComposing() && compositionString.IsEmpty()) {
+    // WARNING: The widget might have been gone after this.
+    DispatchCompositionCommitEvent(activeContext, &EmptyString());
+  }
+}
+
+nsresult IMContextWrapper::EndIMEComposition(nsWindow* aCaller) {
+  if (MOZ_UNLIKELY(IsDestroyed())) {
+    return NS_OK;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p EndIMEComposition(aCaller=0x%p), "
+           "mCompositionState=%s",
+           this, aCaller, GetCompositionStateName()));
+
+  if (aCaller != mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   EndIMEComposition(), FAILED, the caller isn't "
+             "focused window, mLastFocusedWindow=0x%p",
+             this, mLastFocusedWindow));
+    return NS_OK;
+  }
+
+  if (!IsComposing()) {
+    return NS_OK;
+  }
+
+  // Currently, GTK has API neither to commit nor to cancel composition
+  // forcibly.  Therefore, TextComposition will recompute commit string for
+  // the request even if native IME will cause unexpected commit string.
+  // So, we don't need to emulate commit or cancel composition with
+  // proper composition events.
+  // XXX ResetIME() might not enough for finishing compositoin on some
+  //     environments.  We should emulate focus change too because some IMEs
+  //     may commit or cancel composition at blur.
+  ResetIME();
+
+  return NS_OK;
+}
+
+void IMContextWrapper::OnLayoutChange() {
+  if (MOZ_UNLIKELY(IsDestroyed())) {
+    return;
+  }
+
+  if (IsComposing()) {
+    SetCursorPosition(GetActiveContext());
+  } else {
+    // If not composing, candidate window position is updated before key
+    // down
+    mSetCursorPositionOnKeyEvent = true;
+  }
+  mLayoutChanged = true;
+}
+
+void IMContextWrapper::OnUpdateComposition() {
+  if (MOZ_UNLIKELY(IsDestroyed())) {
+    return;
+  }
+
+  if (!IsComposing()) {
+    // Composition has been committed.  So we need update selection for
+    // caret later
+    mContentSelection.reset();
+    EnsureToCacheContentSelection();
+    mSetCursorPositionOnKeyEvent = true;
+  }
+
+  // If we've already set candidate window position, we don't need to update
+  // the position with update composition notification.
+  if (!mLayoutChanged) {
+    SetCursorPosition(GetActiveContext());
+  }
+}
+
+void IMContextWrapper::SetInputContext(nsWindow* aCaller,
+                                       const InputContext* aContext,
+                                       const InputContextAction* aAction) {
+  if (MOZ_UNLIKELY(IsDestroyed())) {
+    return;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p SetInputContext(aCaller=0x%p, aContext={ mIMEState={ "
+           "mEnabled=%s }, mHTMLInputType=%s })",
+           this, aCaller, ToString(aContext->mIMEState.mEnabled).c_str(),
+           NS_ConvertUTF16toUTF8(aContext->mHTMLInputType).get()));
+
+  if (aCaller != mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   SetInputContext(), FAILED, "
+             "the caller isn't focused window, mLastFocusedWindow=0x%p",
+             this, mLastFocusedWindow));
+    return;
+  }
+
+  if (!mContext) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   SetInputContext(), FAILED, "
+             "there are no context",
+             this));
+    return;
+  }
+
+  if (sLastFocusedContext != this) {
+    mInputContext = *aContext;
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   SetInputContext(), succeeded, "
+             "but we're not active",
+             this));
+    return;
+  }
+
+  const bool changingEnabledState =
+      aContext->IsInputAttributeChanged(mInputContext);
+
+  // Release current IME focus if IME is enabled.
+  if (changingEnabledState && mInputContext.mIMEState.IsEditable()) {
+    if (IsComposing()) {
+      EndIMEComposition(mLastFocusedWindow);
+    }
+    if (mIMEFocusState == IMEFocusState::Focused) {
+      NotifyIMEOfFocusChange(IMEFocusState::BlurredWithoutFocusChange);
+    }
+  }
+
+  mInputContext = *aContext;
+  mSetInputPurposeAndInputHints = false;
+
+  if (!changingEnabledState || !mInputContext.mIMEState.IsEditable()) {
+    return;
+  }
+
+  // If the input context was temporarily disabled without a focus change,
+  // it must be ready to query content even if the focused content is in
+  // a remote process.  In this case, we should set IME focus right now.
+  if (mIMEFocusState == IMEFocusState::BlurredWithoutFocusChange) {
+    SetInputPurposeAndInputHints();
+    NotifyIMEOfFocusChange(IMEFocusState::Focused);
+    return;
+  }
+
+  // Otherwise, we cannot set input-purpose and input-hints right now because
+  // setting them may require to set focus immediately for IME own's UI.
+  // However, at this moment, `ContentCacheInParent` does not have content
+  // cache, it'll be available after `NOTIFY_IME_OF_FOCUS` notification.
+  // Therefore, we set them at receiving the notification.
+  mSetInputPurposeAndInputHints = true;
+}
+
+void IMContextWrapper::SetInputPurposeAndInputHints() {
+  GtkIMContext* currentContext = GetCurrentContext();
+  if (!currentContext) {
+    return;
+  }
+
+  GtkInputPurpose purpose = GTK_INPUT_PURPOSE_FREE_FORM;
+  const nsString& inputType = mInputContext.mHTMLInputType;
+  // Password case has difficult issue.  Desktop IMEs disable composition if
+  // input-purpose is password.  For disabling IME on |ime-mode: disabled;|, we
+  // need to check mEnabled value instead of inputType value.  This hack also
+  // enables composition on <input type="password" style="ime-mode: enabled;">.
+  // This is right behavior of ime-mode on desktop.
+  //
+  // On the other hand, IME for tablet devices may provide a specific software
+  // keyboard for password field.  If so, the behavior might look strange on
+  // both:
+  //   <input type="text" style="ime-mode: disabled;">
+  //   <input type="password" style="ime-mode: enabled;">
+  //
+  // Temporarily, we should focus on desktop environment for now.  I.e., let's
+  // ignore tablet devices for now.  When somebody reports actual trouble on
+  // tablet devices, we should try to look for a way to solve actual problem.
+  if (mInputContext.mIMEState.mEnabled == IMEEnabled::Password) {
+    purpose = GTK_INPUT_PURPOSE_PASSWORD;
+  } else if (inputType.EqualsLiteral("email")) {
+    purpose = GTK_INPUT_PURPOSE_EMAIL;
+  } else if (inputType.EqualsLiteral("url")) {
+    purpose = GTK_INPUT_PURPOSE_URL;
+  } else if (inputType.EqualsLiteral("tel")) {
+    purpose = GTK_INPUT_PURPOSE_PHONE;
+  } else if (inputType.EqualsLiteral("number")) {
+    purpose = GTK_INPUT_PURPOSE_NUMBER;
+  } else if (mInputContext.mHTMLInputMode.EqualsLiteral("decimal")) {
+    purpose = GTK_INPUT_PURPOSE_NUMBER;
+  } else if (mInputContext.mHTMLInputMode.EqualsLiteral("email")) {
+    purpose = GTK_INPUT_PURPOSE_EMAIL;
+  } else if (mInputContext.mHTMLInputMode.EqualsLiteral("numeric")) {
+    purpose = GTK_INPUT_PURPOSE_DIGITS;
+  } else if (mInputContext.mHTMLInputMode.EqualsLiteral("tel")) {
+    purpose = GTK_INPUT_PURPOSE_PHONE;
+  } else if (mInputContext.mHTMLInputMode.EqualsLiteral("url")) {
+    purpose = GTK_INPUT_PURPOSE_URL;
+  }
+  // Search by type and inputmode isn't supported on GTK.
+
+  g_object_set(currentContext, "input-purpose", purpose, nullptr);
+
+  // Although GtkInputHints is enum type, value is bit field.
+  gint hints = GTK_INPUT_HINT_NONE;
+  if (mInputContext.mHTMLInputMode.EqualsLiteral("none")) {
+    hints |= GTK_INPUT_HINT_INHIBIT_OSK;
+  }
+
+  if (mInputContext.mAutocapitalize.EqualsLiteral("characters")) {
+    hints |= GTK_INPUT_HINT_UPPERCASE_CHARS;
+  } else if (mInputContext.mAutocapitalize.EqualsLiteral("sentences")) {
+    hints |= GTK_INPUT_HINT_UPPERCASE_SENTENCES;
+  } else if (mInputContext.mAutocapitalize.EqualsLiteral("words")) {
+    hints |= GTK_INPUT_HINT_UPPERCASE_WORDS;
+  }
+
+  g_object_set(currentContext, "input-hints", hints, nullptr);
+}
+
+InputContext IMContextWrapper::GetInputContext() {
+  mInputContext.mIMEState.mOpen = IMEState::OPEN_STATE_NOT_SUPPORTED;
+  return mInputContext;
+}
+
+GtkIMContext* IMContextWrapper::GetCurrentContext() const {
+  if (IsEnabled()) {
+    return mContext;
+  }
+  if (mInputContext.mIMEState.mEnabled == IMEEnabled::Password) {
+    return mSimpleContext;
+  }
+  return mDummyContext;
+}
+
+bool IMContextWrapper::IsValidContext(GtkIMContext* aContext) const {
+  if (!aContext) {
+    return false;
+  }
+  return aContext == mContext || aContext == mSimpleContext ||
+         aContext == mDummyContext;
+}
+
+bool IMContextWrapper::IsEnabled() const {
+  return mInputContext.mIMEState.mEnabled == IMEEnabled::Enabled ||
+         (!sUseSimpleContext &&
+          mInputContext.mIMEState.mEnabled == IMEEnabled::Password);
+}
+
+void IMContextWrapper::NotifyIMEOfFocusChange(IMEFocusState aIMEFocusState) {
+  MOZ_ASSERT_IF(aIMEFocusState == IMEFocusState::BlurredWithoutFocusChange,
+                mIMEFocusState != IMEFocusState::Blurred);
+  if (mIMEFocusState == aIMEFocusState) {
+    return;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p NotifyIMEOfFocusChange(aIMEFocusState=%s), mIMEFocusState=%s, "
+           "sLastFocusedContext=0x%p",
+           this, ToString(aIMEFocusState).c_str(),
+           ToString(mIMEFocusState).c_str(), sLastFocusedContext));
+  MOZ_ASSERT(!mSetInputPurposeAndInputHints);
+
+  // If we've already made IME blurred at setting the input context disabled
+  // and it's now completely blurred by a focus move, we need only to update
+  // mIMEFocusState and when the input context gets enabled, we cannot set
+  // IME focus immediately.
+  if (aIMEFocusState == IMEFocusState::Blurred &&
+      mIMEFocusState == IMEFocusState::BlurredWithoutFocusChange) {
+    mIMEFocusState = IMEFocusState::Blurred;
+    return;
+  }
+
+  auto Blur = [&](IMEFocusState aInternalState) {
+    GtkIMContext* currentContext = GetCurrentContext();
+    if (MOZ_UNLIKELY(!currentContext)) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   NotifyIMEOfFocusChange()::Blur(), FAILED, "
+               "there is no context",
+               this));
+      return;
+    }
+    gtk_im_context_focus_out(currentContext);
+    mIMEFocusState = aInternalState;
+  };
+
+  if (aIMEFocusState != IMEFocusState::Focused) {
+    return Blur(aIMEFocusState);
+  }
+
+  GtkIMContext* currentContext = GetCurrentContext();
+  if (MOZ_UNLIKELY(!currentContext)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   NotifyIMEOfFocusChange(), FAILED, "
+             "there is no context",
+             this));
+    return;
+  }
+
+  if (sLastFocusedContext && sLastFocusedContext != this) {
+    sLastFocusedContext->NotifyIMEOfFocusChange(IMEFocusState::Blurred);
+  }
+
+  sLastFocusedContext = this;
+
+  // Forget all posted key events when focus is moved since they shouldn't
+  // be fired in different editor.
+  sWaitingSynthesizedKeyPressHardwareKeyCode = 0;
+  mPostingKeyEvents.Clear();
+
+  gtk_im_context_focus_in(currentContext);
+  mIMEFocusState = aIMEFocusState;
+  mSetCursorPositionOnKeyEvent = true;
+
+  if (!IsEnabled()) {
+    // We should release IME focus for uim and scim.
+    // These IMs are using snooper that is released at losing focus.
+    Blur(IMEFocusState::BlurredWithoutFocusChange);
+  }
+}
+
+void IMContextWrapper::OnSelectionChange(
+    nsWindow* aCaller, const IMENotification& aIMENotification) {
+  const bool isSelectionRangeChanged =
+      mContentSelection.isNothing() ||
+      !aIMENotification.mSelectionChangeData.EqualsRange(
+          mContentSelection.ref());
+  mContentSelection =
+      Some(ContentSelection(aIMENotification.mSelectionChangeData));
+  const bool retrievedSurroundingSignalReceived =
+      mRetrieveSurroundingSignalReceived;
+  mRetrieveSurroundingSignalReceived = false;
+
+  if (MOZ_UNLIKELY(IsDestroyed())) {
+    return;
+  }
+
+  const IMENotification::SelectionChangeDataBase& selectionChangeData =
+      aIMENotification.mSelectionChangeData;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p OnSelectionChange(aCaller=0x%p, aIMENotification={ "
+           "mSelectionChangeData=%s }), "
+           "mCompositionState=%s, mIsDeletingSurrounding=%s, "
+           "mRetrieveSurroundingSignalReceived=%s, isSelectionRangeChanged=%s",
+           this, aCaller, ToString(selectionChangeData).c_str(),
+           GetCompositionStateName(), ToChar(mIsDeletingSurrounding),
+           ToChar(retrievedSurroundingSignalReceived),
+           ToChar(isSelectionRangeChanged)));
+
+  if (aCaller != mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   OnSelectionChange(), FAILED, "
+             "the caller isn't focused window, mLastFocusedWindow=0x%p",
+             this, mLastFocusedWindow));
+    return;
+  }
+
+  if (!IsComposing()) {
+    // Now we have no composition (mostly situation on calling this method)
+    // If we have it, it will set by
+    // NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED.
+    mSetCursorPositionOnKeyEvent = true;
+  }
+
+  // The focused editor might have placeholder text with normal text node.
+  // In such case, the text node must be removed from a compositionstart
+  // event handler.  So, we're dispatching eCompositionStart,
+  // we should ignore selection change notification.
+  if (mCompositionState == eCompositionState_CompositionStartDispatched) {
+    if (NS_WARN_IF(mContentSelection.isNothing())) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   OnSelectionChange(), FAILED, "
+               "new offset is too large, cannot keep composing",
+               this));
+    } else if (mContentSelection->HasRange()) {
+      // Modify the selection start offset with new offset.
+      mCompositionStart = mContentSelection->OffsetAndDataRef().StartOffset();
+      // XXX We should modify mSelectedStringRemovedByComposition?
+      // But how?
+      MOZ_LOG(gIMELog, LogLevel::Debug,
+              ("0x%p   OnSelectionChange(), ignored, mCompositionStart "
+               "is updated to %u, the selection change doesn't cause "
+               "resetting IM context",
+               this, mCompositionStart));
+      // And don't reset the IM context.
+      return;
+    } else {
+      MOZ_LOG(
+          gIMELog, LogLevel::Debug,
+          ("0x%p   OnSelectionChange(), ignored, because of no selection range",
+           this));
+      return;
+    }
+    // Otherwise, reset the IM context due to impossible to keep composing.
+  }
+
+  // If the selection change is caused by deleting surrounding text,
+  // we shouldn't need to notify IME of selection change.
+  if (mIsDeletingSurrounding) {
+    return;
+  }
+
+  bool occurredBeforeComposition =
+      IsComposing() && !selectionChangeData.mOccurredDuringComposition &&
+      !selectionChangeData.mCausedByComposition;
+  if (occurredBeforeComposition) {
+    mPendingResettingIMContext = true;
+  }
+
+  // When the selection change is caused by dispatching composition event,
+  // selection set event and/or occurred before starting current composition,
+  // we shouldn't notify IME of that and commit existing composition.
+  // Don't do this even if selection is not changed actually.  For example,
+  // fcitx has direct input mode which does not insert composing string, but
+  // inserts commited text for each key sequence (i.e., there is "invisible"
+  // composition string).  In the world after bug 1712269, we don't use a
+  // set of composition events for this kind of IME.  Therefore,
+  // SelectionChangeData.mCausedByComposition is not expected value for here
+  // if this call is caused by a preceding commit.  And if the preceding commit
+  // is triggered by a key type for next word, resetting IME state makes fcitx
+  // discard the pending input for the next word.  Thus, we need to check
+  // whether the selection range is actually changed here.
+  if (!selectionChangeData.mCausedByComposition &&
+      !selectionChangeData.mCausedBySelectionEvent && isSelectionRangeChanged &&
+      !occurredBeforeComposition) {
+    // Hack for ibus-pinyin.  ibus-pinyin will synthesize a set of
+    // composition which commits with empty string after calling
+    // gtk_im_context_reset().  Therefore, selecting text causes
+    // unexpectedly removing it.  For preventing it but not breaking the
+    // other IMEs which use surrounding text, we should call it only when
+    // surrounding text has been retrieved after last selection range was
+    // set.  If it's not retrieved, that means that current IME doesn't
+    // have any content cache, so, it must not need the notification of
+    // selection change.
+    if (IsComposing() || retrievedSurroundingSignalReceived) {
+      ResetIME();
+    }
+  }
+}
+
+/* static */
+void IMContextWrapper::OnThemeChanged() {
+  if (auto* provider = SelectionStyleProvider::GetExistingInstance()) {
+    provider->OnThemeChanged();
+  }
+}
+
+/* static */
+void IMContextWrapper::OnStartCompositionCallback(GtkIMContext* aContext,
+                                                  IMContextWrapper* aModule) {
+  aModule->OnStartCompositionNative(aContext);
+}
+
+void IMContextWrapper::OnStartCompositionNative(GtkIMContext* aContext) {
+  // IME may synthesize composition asynchronously after filtering a
+  // GDK_KEY_PRESS event.  In that case, we should handle composition with
+  // emulating the usual case, i.e., this is called in the stack of
+  // OnKeyEvent().
+  Maybe<AutoRestore<GdkEventKey*>> maybeRestoreProcessingKeyEvent;
+  if (!mProcessingKeyEvent && !mPostingKeyEvents.IsEmpty()) {
+    GdkEventKey* keyEvent = mPostingKeyEvents.GetFirstEvent();
+    if (keyEvent && keyEvent->type == GDK_KEY_PRESS &&
+        KeymapWrapper::ComputeDOMKeyNameIndex(keyEvent) ==
+            KEY_NAME_INDEX_USE_STRING) {
+      maybeRestoreProcessingKeyEvent.emplace(mProcessingKeyEvent);
+      mProcessingKeyEvent = mPostingKeyEvents.GetFirstEvent();
+    }
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p OnStartCompositionNative(aContext=0x%p), "
+           "current context=0x%p, mComposingContext=0x%p",
+           this, aContext, GetCurrentContext(), mComposingContext));
+
+  // See bug 472635, we should do nothing if IM context doesn't match.
+  if (GetCurrentContext() != aContext) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   OnStartCompositionNative(), FAILED, "
+             "given context doesn't match",
+             this));
+    return;
+  }
+
+  if (mComposingContext && aContext != mComposingContext) {
+    // XXX For now, we should ignore this odd case, just logging.
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   OnStartCompositionNative(), Warning, "
+             "there is already a composing context but starting new "
+             "composition with different context",
+             this));
+  }
+
+  // IME may start composition without "preedit_start" signal.  Therefore,
+  // mComposingContext will be initialized in DispatchCompositionStart().
+
+  if (!DispatchCompositionStart(aContext)) {
+    return;
+  }
+  mCompositionTargetRange.mOffset = mCompositionStart;
+  mCompositionTargetRange.mLength = 0;
+}
+
+/* static */
+void IMContextWrapper::OnEndCompositionCallback(GtkIMContext* aContext,
+                                                IMContextWrapper* aModule) {
+  aModule->OnEndCompositionNative(aContext);
+}
+
+void IMContextWrapper::OnEndCompositionNative(GtkIMContext* aContext) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p OnEndCompositionNative(aContext=0x%p), mComposingContext=0x%p",
+           this, aContext, mComposingContext));
+
+  // See bug 472635, we should do nothing if IM context doesn't match.
+  // Note that if this is called after focus move, the context may different
+  // from any our owning context.
+  if (!IsValidContext(aContext)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p    OnEndCompositionNative(), FAILED, "
+             "given context doesn't match with any context",
+             this));
+    return;
+  }
+
+  // If we've not started composition with aContext, we should ignore it.
+  if (aContext != mComposingContext) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p    OnEndCompositionNative(), Warning, "
+             "given context doesn't match with mComposingContext",
+             this));
+    return;
+  }
+
+  g_object_unref(mComposingContext);
+  mComposingContext = nullptr;
+
+  // If we already handled the commit event, we should do nothing here.
+  if (IsComposing()) {
+    if (!DispatchCompositionCommitEvent(aContext)) {
+      // If the widget is destroyed, we should do nothing anymore.
+      return;
+    }
+  }
+
+  if (mPendingResettingIMContext) {
+    ResetIME();
+  }
+}
+
+/* static */
+void IMContextWrapper::OnChangeCompositionCallback(GtkIMContext* aContext,
+                                                   IMContextWrapper* aModule) {
+  RefPtr module = aModule;
+  module->OnChangeCompositionNative(aContext);
+
+  if (module->IsDestroyed()) {
+    // A strong reference is already held during "preedit-changed" emission,
+    // but _ibus_context_destroy_cb() in ibus 1.5.28 and
+    // _fcitx_im_context_close_im_cb() in fcitx 4.2.9.9 want their
+    // GtkIMContexts to live a little longer.  See bug 1824634.
+    NS_DispatchToMainThread(
+        NS_NewRunnableFunction(__func__, [context = RefPtr{aContext}]() {}));
+  }
+}
+
+void IMContextWrapper::OnChangeCompositionNative(GtkIMContext* aContext) {
+  // IME may synthesize composition asynchronously after filtering a
+  // GDK_KEY_PRESS event.  In that case, we should handle composition with
+  // emulating the usual case, i.e., this is called in the stack of
+  // OnKeyEvent().
+  Maybe<AutoRestore<GdkEventKey*>> maybeRestoreProcessingKeyEvent;
+  if (!mProcessingKeyEvent && !mPostingKeyEvents.IsEmpty()) {
+    GdkEventKey* keyEvent = mPostingKeyEvents.GetFirstEvent();
+    if (keyEvent && keyEvent->type == GDK_KEY_PRESS &&
+        KeymapWrapper::ComputeDOMKeyNameIndex(keyEvent) ==
+            KEY_NAME_INDEX_USE_STRING) {
+      maybeRestoreProcessingKeyEvent.emplace(mProcessingKeyEvent);
+      mProcessingKeyEvent = mPostingKeyEvents.GetFirstEvent();
+    }
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p OnChangeCompositionNative(aContext=0x%p), "
+           "mComposingContext=0x%p",
+           this, aContext, mComposingContext));
+
+  // See bug 472635, we should do nothing if IM context doesn't match.
+  // Note that if this is called after focus move, the context may different
+  // from any our owning context.
+  if (!IsValidContext(aContext)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   OnChangeCompositionNative(), FAILED, "
+             "given context doesn't match with any context",
+             this));
+    return;
+  }
+
+  if (mComposingContext && aContext != mComposingContext) {
+    // XXX For now, we should ignore this odd case, just logging.
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   OnChangeCompositionNative(), Warning, "
+             "given context doesn't match with composing context",
+             this));
+  }
+
+  nsAutoString compositionString;
+  GetCompositionString(aContext, compositionString);
+  if (!IsComposing() && compositionString.IsEmpty()) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   OnChangeCompositionNative(), Warning, does nothing "
+             "because has not started composition and composing string is "
+             "empty",
+             this));
+    mDispatchedCompositionString.Truncate();
+    return;  // Don't start the composition with empty string.
+  }
+
+  // Be aware, widget can be gone
+  DispatchCompositionChangeEvent(aContext, compositionString);
+}
+
+/* static */
+gboolean IMContextWrapper::OnRetrieveSurroundingCallback(
+    GtkIMContext* aContext, IMContextWrapper* aModule) {
+  return aModule->OnRetrieveSurroundingNative(aContext);
+}
+
+gboolean IMContextWrapper::OnRetrieveSurroundingNative(GtkIMContext* aContext) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p OnRetrieveSurroundingNative(aContext=0x%p), "
+           "current context=0x%p",
+           this, aContext, GetCurrentContext()));
+
+  // See bug 472635, we should do nothing if IM context doesn't match.
+  if (GetCurrentContext() != aContext) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   OnRetrieveSurroundingNative(), FAILED, "
+             "given context doesn't match",
+             this));
+    return FALSE;
+  }
+
+  nsAutoString uniStr;
+  uint32_t cursorPos;
+  if (NS_FAILED(GetCurrentParagraph(uniStr, cursorPos))) {
+    return FALSE;
+  }
+
+  // Despite taking a pointer and a length, IBus wants the string to be
+  // zero-terminated and doesn't like U+0000 within the string.
+  uniStr.ReplaceChar(char16_t(0), char16_t(0xFFFD));
+
+  NS_ConvertUTF16toUTF8 utf8Str(nsDependentSubstring(uniStr, 0, cursorPos));
+  uint32_t cursorPosInUTF8 = utf8Str.Length();
+  AppendUTF16toUTF8(nsDependentSubstring(uniStr, cursorPos), utf8Str);
+  gtk_im_context_set_surrounding(aContext, utf8Str.get(), utf8Str.Length(),
+                                 cursorPosInUTF8);
+  mRetrieveSurroundingSignalReceived = true;
+  return TRUE;
+}
+
+/* static */
+gboolean IMContextWrapper::OnDeleteSurroundingCallback(
+    GtkIMContext* aContext, gint aOffset, gint aNChars,
+    IMContextWrapper* aModule) {
+  return aModule->OnDeleteSurroundingNative(aContext, aOffset, aNChars);
+}
+
+gboolean IMContextWrapper::OnDeleteSurroundingNative(GtkIMContext* aContext,
+                                                     gint aOffset,
+                                                     gint aNChars) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p OnDeleteSurroundingNative(aContext=0x%p, aOffset=%d, "
+           "aNChar=%d), current context=0x%p",
+           this, aContext, aOffset, aNChars, GetCurrentContext()));
+
+  // See bug 472635, we should do nothing if IM context doesn't match.
+  if (GetCurrentContext() != aContext) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   OnDeleteSurroundingNative(), FAILED, "
+             "given context doesn't match",
+             this));
+    return FALSE;
+  }
+
+  AutoRestore<bool> saveDeletingSurrounding(mIsDeletingSurrounding);
+  mIsDeletingSurrounding = true;
+  if (NS_SUCCEEDED(DeleteText(aContext, aOffset, (uint32_t)aNChars))) {
+    return TRUE;
+  }
+
+  // failed
+  MOZ_LOG(gIMELog, LogLevel::Error,
+          ("0x%p   OnDeleteSurroundingNative(), FAILED, "
+           "cannot delete text",
+           this));
+  return FALSE;
+}
+
+/* static */
+void IMContextWrapper::OnCommitCompositionCallback(GtkIMContext* aContext,
+                                                   const gchar* aString,
+                                                   IMContextWrapper* aModule) {
+  aModule->OnCommitCompositionNative(aContext, aString);
+}
+
+void IMContextWrapper::OnCommitCompositionNative(GtkIMContext* aContext,
+                                                 const gchar* aUTF8Char) {
+  const gchar emptyStr = 0;
+  const gchar* commitString = aUTF8Char ? aUTF8Char : &emptyStr;
+  NS_ConvertUTF8toUTF16 utf16CommitString(commitString);
+
+  // IME may synthesize composition asynchronously after filtering a
+  // GDK_KEY_PRESS event.  In that case, we should handle composition with
+  // emulating the usual case, i.e., this is called in the stack of
+  // OnKeyEvent().
+  Maybe<AutoRestore<GdkEventKey*>> maybeRestoreProcessingKeyEvent;
+  if (!mProcessingKeyEvent && !mPostingKeyEvents.IsEmpty()) {
+    GdkEventKey* keyEvent = mPostingKeyEvents.GetFirstEvent();
+    if (keyEvent && keyEvent->type == GDK_KEY_PRESS &&
+        KeymapWrapper::ComputeDOMKeyNameIndex(keyEvent) ==
+            KEY_NAME_INDEX_USE_STRING) {
+      maybeRestoreProcessingKeyEvent.emplace(mProcessingKeyEvent);
+      mProcessingKeyEvent = mPostingKeyEvents.GetFirstEvent();
+    }
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p OnCommitCompositionNative(aContext=0x%p), "
+           "current context=0x%p, active context=0x%p, commitString=\"%s\", "
+           "mProcessingKeyEvent=0x%p, IsComposingOn(aContext)=%s",
+           this, aContext, GetCurrentContext(), GetActiveContext(),
+           commitString, mProcessingKeyEvent, ToChar(IsComposingOn(aContext))));
+
+  // See bug 472635, we should do nothing if IM context doesn't match.
+  if (!IsValidContext(aContext)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   OnCommitCompositionNative(), FAILED, "
+             "given context doesn't match",
+             this));
+    return;
+  }
+
+  // If we are not in composition and committing with empty string,
+  // we need to do nothing because if we continued to handle this
+  // signal, we would dispatch compositionstart, text, compositionend
+  // events with empty string.  Of course, they are unnecessary events
+  // for Web applications and our editor.
+  if (!IsComposingOn(aContext) && utf16CommitString.IsEmpty()) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   OnCommitCompositionNative(), Warning, does nothing "
+             "because has not started composition and commit string is empty",
+             this));
+    return;
+  }
+
+  // If IME doesn't change their keyevent that generated this commit,
+  // we should treat that IME didn't handle the key event because
+  // web applications want to receive "keydown" and "keypress" event
+  // in such case.
+  // NOTE: While a key event is being handled, this might be caused on
+  // current context.  Otherwise, this may be caused on active context.
+  if (!IsComposingOn(aContext) && mProcessingKeyEvent &&
+      mProcessingKeyEvent->type == GDK_KEY_PRESS &&
+      aContext == GetCurrentContext()) {
+    char keyval_utf8[8]; /* should have at least 6 bytes of space */
+    gint keyval_utf8_len;
+    guint32 keyval_unicode;
+
+    keyval_unicode = gdk_keyval_to_unicode(mProcessingKeyEvent->keyval);
+    keyval_utf8_len = g_unichar_to_utf8(keyval_unicode, keyval_utf8);
+    keyval_utf8[keyval_utf8_len] = '\0';
+
+    // If committing string is exactly same as a character which is
+    // produced by the key, eKeyDown and eKeyPress event should be
+    // dispatched by the caller of OnKeyEvent() normally.  Note that
+    // mMaybeInDeadKeySequence will be set to false by OnKeyEvent()
+    // since we set mFallbackToKeyEvent to true here.
+    if (!strcmp(commitString, keyval_utf8)) {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   OnCommitCompositionNative(), "
+               "we'll send normal key event",
+               this));
+      mFallbackToKeyEvent = true;
+      return;
+    }
+
+    // If we're in a dead key sequence, commit string is a character in
+    // the BMP and mProcessingKeyEvent produces some characters but it's
+    // not same as committing string, we should dispatch an eKeyPress
+    // event from here.
+    WidgetKeyboardEvent keyDownEvent(true, eKeyDown, mLastFocusedWindow);
+    KeymapWrapper::InitKeyEvent(keyDownEvent, mProcessingKeyEvent, false);
+    if (mMaybeInDeadKeySequence && utf16CommitString.Length() == 1 &&
+        keyDownEvent.mKeyNameIndex == KEY_NAME_INDEX_USE_STRING) {
+      mKeyboardEventWasDispatched = true;
+      // Anyway, we're not in dead key sequence anymore.
+      mMaybeInDeadKeySequence = false;
+
+      RefPtr<TextEventDispatcher> dispatcher = GetTextEventDispatcher();
+      nsresult rv = dispatcher->BeginNativeInputTransaction();
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        MOZ_LOG(gIMELog, LogLevel::Error,
+                ("0x%p   OnCommitCompositionNative(), FAILED, "
+                 "due to BeginNativeInputTransaction() failure",
+                 this));
+        return;
+      }
+
+      // First, dispatch eKeyDown event.
+      keyDownEvent.mKeyValue = utf16CommitString;
+      nsEventStatus status = nsEventStatus_eIgnore;
+      bool dispatched = dispatcher->DispatchKeyboardEvent(
+          eKeyDown, keyDownEvent, status, mProcessingKeyEvent);
+      if (!dispatched || status == nsEventStatus_eConsumeNoDefault) {
+        mKeyboardEventWasConsumed = true;
+        MOZ_LOG(gIMELog, LogLevel::Info,
+                ("0x%p   OnCommitCompositionNative(), "
+                 "doesn't dispatch eKeyPress event because the preceding "
+                 "eKeyDown event was not dispatched or was consumed",
+                 this));
+        return;
+      }
+      if (mLastFocusedWindow != keyDownEvent.mWidget ||
+          mLastFocusedWindow->Destroyed()) {
+        MOZ_LOG(gIMELog, LogLevel::Warning,
+                ("0x%p   OnCommitCompositionNative(), Warning, "
+                 "stop dispatching eKeyPress event because the preceding "
+                 "eKeyDown event caused changing focused widget or "
+                 "destroyed",
+                 this));
+        return;
+      }
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   OnCommitCompositionNative(), "
+               "dispatched eKeyDown event for the committed character",
+               this));
+
+      // Next, dispatch eKeyPress event.
+      dispatcher->MaybeDispatchKeypressEvents(keyDownEvent, status,
+                                              mProcessingKeyEvent);
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   OnCommitCompositionNative(), "
+               "dispatched eKeyPress event for the committed character",
+               this));
+      return;
+    }
+  }
+
+  NS_ConvertUTF8toUTF16 str(commitString);
+  // Be aware, widget can be gone
+  DispatchCompositionCommitEvent(aContext, &str);
+}
+
+void IMContextWrapper::GetCompositionString(GtkIMContext* aContext,
+                                            nsAString& aCompositionString) {
+  gchar* preedit_string;
+  gint cursor_pos;
+  PangoAttrList* feedback_list;
+  gtk_im_context_get_preedit_string(aContext, &preedit_string, &feedback_list,
+                                    &cursor_pos);
+  if (preedit_string && *preedit_string) {
+    CopyUTF8toUTF16(MakeStringSpan(preedit_string), aCompositionString);
+  } else {
+    aCompositionString.Truncate();
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p GetCompositionString(aContext=0x%p), "
+           "aCompositionString=\"%s\"",
+           this, aContext, preedit_string));
+
+  pango_attr_list_unref(feedback_list);
+  g_free(preedit_string);
+}
+
+bool IMContextWrapper::MaybeDispatchKeyEventAsProcessedByIME(
+    EventMessage aFollowingEvent) {
+  if (!mLastFocusedWindow) {
+    return false;
+  }
+
+  if (!mIsKeySnooped &&
+      ((!mProcessingKeyEvent && mPostingKeyEvents.IsEmpty()) ||
+       (mProcessingKeyEvent && mKeyboardEventWasDispatched))) {
+    return true;
+  }
+
+  // A "keydown" or "keyup" event handler may change focus with the
+  // following event.  In such case, we need to cancel this composition.
+  // So, we need to store IM context now because mComposingContext may be
+  // overwritten with different context if calling this method recursively.
+  // Note that we don't need to grab the context here because |context|
+  // will be used only for checking if it's same as mComposingContext.
+  GtkIMContext* oldCurrentContext = GetCurrentContext();
+  GtkIMContext* oldComposingContext = mComposingContext;
+
+  RefPtr<nsWindow> lastFocusedWindow(mLastFocusedWindow);
+
+  if (mProcessingKeyEvent || !mPostingKeyEvents.IsEmpty()) {
+    if (mProcessingKeyEvent) {
+      mKeyboardEventWasDispatched = true;
+    }
+    // If we're not handling a key event synchronously, the signal may be
+    // sent by IME without sending key event to us.  In such case, we
+    // should dispatch keyboard event for the last key event which was
+    // posted to other IME process.
+    GdkEventKey* sourceEvent = mProcessingKeyEvent
+                                   ? mProcessingKeyEvent
+                                   : mPostingKeyEvents.GetFirstEvent();
+
+    MOZ_LOG(
+        gIMELog, LogLevel::Info,
+        ("0x%p MaybeDispatchKeyEventAsProcessedByIME("
+         "aFollowingEvent=%s), dispatch %s %s "
+         "event: { type=%s, keyval=%s, unicode=0x%X, state=%s, "
+         "time=%u, hardware_keycode=%u, group=%u }",
+         this, ToChar(aFollowingEvent),
+         ToChar(sourceEvent->type == GDK_KEY_PRESS ? eKeyDown : eKeyUp),
+         mProcessingKeyEvent ? "processing" : "posted",
+         GetEventType(sourceEvent), gdk_keyval_name(sourceEvent->keyval),
+         gdk_keyval_to_unicode(sourceEvent->keyval),
+         GetEventStateName(sourceEvent->state, mIMContextID).get(),
+         sourceEvent->time, sourceEvent->hardware_keycode, sourceEvent->group));
+
+    // Let's dispatch eKeyDown event or eKeyUp event now.  Note that only
+    // when we're not in a dead key composition, we should mark the
+    // eKeyDown and eKeyUp event as "processed by IME" since we should
+    // expose raw keyCode and key value to web apps the key event is a
+    // part of a dead key sequence.
+    // FYI: We should ignore if default of preceding keydown or keyup
+    //      event is prevented since even on the other browsers, web
+    //      applications cannot cancel the following composition event.
+    //      Spec bug: https://github.com/w3c/uievents/issues/180
+    KeymapWrapper::DispatchKeyDownOrKeyUpEvent(lastFocusedWindow, sourceEvent,
+                                               !mMaybeInDeadKeySequence,
+                                               &mKeyboardEventWasConsumed);
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   MaybeDispatchKeyEventAsProcessedByIME(), keydown or keyup "
+             "event is dispatched",
+             this));
+
+    if (!mProcessingKeyEvent) {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   MaybeDispatchKeyEventAsProcessedByIME(), removing first "
+               "event from the queue",
+               this));
+      mPostingKeyEvents.RemoveEvent(sourceEvent);
+    }
+  } else {
+    MOZ_ASSERT(mIsKeySnooped);
+    // Currently, we support key snooper mode of uim and wayland only.
+    MOZ_ASSERT(mIMContextID == IMContextID::Uim ||
+               mIMContextID == IMContextID::Wayland);
+    // uim sends "preedit_start" signal and "preedit_changed" separately
+    // at starting composition, "commit" and "preedit_end" separately at
+    // committing composition.
+
+    // Currently, we should dispatch only fake eKeyDown event because
+    // we cannot decide which is the last signal of each key operation
+    // and Chromium also dispatches only "keydown" event in this case.
+    bool dispatchFakeKeyDown = false;
+    switch (aFollowingEvent) {
+      case eCompositionStart:
+      case eCompositionCommit:
+      case eCompositionCommitAsIs:
+      case eContentCommandInsertText:
+        dispatchFakeKeyDown = true;
+        break;
+      // XXX Unfortunately, I don't have a good idea to prevent to
+      //     dispatch redundant eKeyDown event for eCompositionStart
+      //     immediately after "delete_surrounding" signal.  However,
+      //     not dispatching eKeyDown event is worse than dispatching
+      //     redundant eKeyDown events.
+      case eContentCommandDelete:
+        dispatchFakeKeyDown = true;
+        break;
+      // We need to prevent to dispatch redundant eKeyDown event for
+      // eCompositionChange immediately after eCompositionStart.  So,
+      // We should not dispatch eKeyDown event if dispatched composition
+      // string is still empty string.
+      case eCompositionChange:
+        dispatchFakeKeyDown = !mDispatchedCompositionString.IsEmpty();
+        break;
+      default:
+        MOZ_ASSERT_UNREACHABLE("Do you forget to handle the case?");
+        break;
+    }
+
+    if (dispatchFakeKeyDown) {
+      WidgetKeyboardEvent fakeKeyDownEvent(true, eKeyDown, lastFocusedWindow);
+      fakeKeyDownEvent.mKeyCode = NS_VK_PROCESSKEY;
+      fakeKeyDownEvent.mKeyNameIndex = KEY_NAME_INDEX_Process;
+      // It's impossible to get physical key information in this case but
+      // this should be okay since web apps shouldn't do anything with
+      // physical key information during composition.
+      fakeKeyDownEvent.mCodeNameIndex = CODE_NAME_INDEX_UNKNOWN;
+
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p MaybeDispatchKeyEventAsProcessedByIME("
+               "aFollowingEvent=%s), dispatch fake eKeyDown event",
+               this, ToChar(aFollowingEvent)));
+
+      KeymapWrapper::DispatchKeyDownOrKeyUpEvent(
+          lastFocusedWindow, fakeKeyDownEvent, &mKeyboardEventWasConsumed);
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   MaybeDispatchKeyEventAsProcessedByIME(), "
+               "fake keydown event is dispatched",
+               this));
+    }
+  }
+
+  if (lastFocusedWindow->IsDestroyed() ||
+      lastFocusedWindow != mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   MaybeDispatchKeyEventAsProcessedByIME(), Warning, the "
+             "focused widget was destroyed/changed by a key event",
+             this));
+    return false;
+  }
+
+  // If the dispatched keydown event caused moving focus and that also
+  // caused changing active context, we need to cancel composition here.
+  if (GetCurrentContext() != oldCurrentContext) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   MaybeDispatchKeyEventAsProcessedByIME(), Warning, the key "
+             "event causes changing active IM context",
+             this));
+    if (mComposingContext == oldComposingContext) {
+      // Only when the context is still composing, we should call
+      // ResetIME() here.  Otherwise, it should've already been
+      // cleaned up.
+      ResetIME();
+    }
+    return false;
+  }
+
+  return true;
+}
+
+bool IMContextWrapper::DispatchCompositionStart(GtkIMContext* aContext) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p DispatchCompositionStart(aContext=0x%p)", this, aContext));
+
+  if (IsComposing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionStart(), FAILED, "
+             "we're already in composition",
+             this));
+    return true;
+  }
+
+  if (!mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionStart(), FAILED, "
+             "there are no focused window in this module",
+             this));
+    return false;
+  }
+
+  if (NS_WARN_IF(!EnsureToCacheContentSelection())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionStart(), FAILED, "
+             "cannot query the selection offset",
+             this));
+    return false;
+  }
+
+  if (NS_WARN_IF(!mContentSelection->HasRange())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionStart(), FAILED, "
+             "due to no selection",
+             this));
+    return false;
+  }
+
+  mComposingContext = static_cast<GtkIMContext*>(g_object_ref(aContext));
+  MOZ_ASSERT(mComposingContext);
+
+  // Keep the last focused window alive
+  RefPtr<nsWindow> lastFocusedWindow(mLastFocusedWindow);
+
+  // XXX The composition start point might be changed by composition events
+  //     even though we strongly hope it doesn't happen.
+  //     Every composition event should have the start offset for the result
+  //     because it may high cost if we query the offset every time.
+  mCompositionStart = mContentSelection->OffsetAndDataRef().StartOffset();
+  mDispatchedCompositionString.Truncate();
+
+  // If this composition is started by a key press, we need to dispatch
+  // eKeyDown or eKeyUp event before dispatching eCompositionStart event.
+  // Note that dispatching a keyboard event which is marked as "processed
+  // by IME" is okay since Chromium also dispatches keyboard event as so.
+  if (!MaybeDispatchKeyEventAsProcessedByIME(eCompositionStart)) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   DispatchCompositionStart(), Warning, "
+             "MaybeDispatchKeyEventAsProcessedByIME() returned false",
+             this));
+    return false;
+  }
+
+  RefPtr<TextEventDispatcher> dispatcher = GetTextEventDispatcher();
+  nsresult rv = dispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionStart(), FAILED, "
+             "due to BeginNativeInputTransaction() failure",
+             this));
+    return false;
+  }
+
+  static bool sHasSetTelemetry = false;
+  if (!sHasSetTelemetry) {
+    sHasSetTelemetry = true;
+    NS_ConvertUTF8toUTF16 im(GetIMName());
+    // 72 is kMaximumKeyStringLength in TelemetryScalar.cpp
+    if (im.Length() > 72) {
+      if (NS_IS_SURROGATE_PAIR(im[72 - 2], im[72 - 1])) {
+        im.Truncate(72 - 2);
+      } else {
+        im.Truncate(72 - 1);
+      }
+      // U+2026 is "..."
+      im.Append(char16_t(0x2026));
+    }
+    Telemetry::ScalarSet(Telemetry::ScalarID::WIDGET_IME_NAME_ON_LINUX, im,
+                         true);
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   DispatchCompositionStart(), dispatching "
+           "compositionstart... (mCompositionStart=%u)",
+           this, mCompositionStart));
+  mCompositionState = eCompositionState_CompositionStartDispatched;
+  nsEventStatus status;
+  dispatcher->StartComposition(status);
+  if (lastFocusedWindow->IsDestroyed() ||
+      lastFocusedWindow != mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionStart(), FAILED, the focused "
+             "widget was destroyed/changed by compositionstart event",
+             this));
+    return false;
+  }
+
+  return true;
+}
+
+bool IMContextWrapper::DispatchCompositionChangeEvent(
+    GtkIMContext* aContext, const nsAString& aCompositionString) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p DispatchCompositionChangeEvent(aContext=0x%p)", this, aContext));
+
+  if (!mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionChangeEvent(), FAILED, "
+             "there are no focused window in this module",
+             this));
+    return false;
+  }
+
+  if (!IsComposing()) {
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   DispatchCompositionChangeEvent(), the composition "
+             "wasn't started, force starting...",
+             this));
+    if (!DispatchCompositionStart(aContext)) {
+      return false;
+    }
+  }
+  // If this composition string change caused by a key press, we need to
+  // dispatch eKeyDown or eKeyUp before dispatching eCompositionChange event.
+  else if (!MaybeDispatchKeyEventAsProcessedByIME(eCompositionChange)) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   DispatchCompositionChangeEvent(), Warning, "
+             "MaybeDispatchKeyEventAsProcessedByIME() returned false",
+             this));
+    return false;
+  }
+
+  RefPtr<TextEventDispatcher> dispatcher = GetTextEventDispatcher();
+  nsresult rv = dispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionChangeEvent(), FAILED, "
+             "due to BeginNativeInputTransaction() failure",
+             this));
+    return false;
+  }
+
+  // Store the selected string which will be removed by following
+  // compositionchange event.
+  if (mCompositionState == eCompositionState_CompositionStartDispatched) {
+    if (NS_WARN_IF(!EnsureToCacheContentSelection(
+            &mSelectedStringRemovedByComposition))) {
+      // XXX How should we behave in this case??
+    } else if (mContentSelection->HasRange()) {
+      // XXX We should assume, for now, any web applications don't change
+      //     selection at handling this compositionchange event.
+      mCompositionStart = mContentSelection->OffsetAndDataRef().StartOffset();
+    } else {
+      // If there is no selection range, we should keep previously storing
+      // mCompositionStart.
+    }
+  }
+
+  RefPtr<TextRangeArray> rangeArray =
+      CreateTextRangeArray(aContext, aCompositionString);
+
+  rv = dispatcher->SetPendingComposition(aCompositionString, rangeArray);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionChangeEvent(), FAILED, "
+             "due to SetPendingComposition() failure",
+             this));
+    return false;
+  }
+
+  mCompositionState = eCompositionState_CompositionChangeEventDispatched;
+
+  // We cannot call SetCursorPosition for e10s-aware.
+  // DispatchEvent is async on e10s, so composition rect isn't updated now
+  // on tab parent.
+  mDispatchedCompositionString = aCompositionString;
+  mLayoutChanged = false;
+  mCompositionTargetRange.mOffset =
+      mCompositionStart + rangeArray->TargetClauseOffset();
+  mCompositionTargetRange.mLength = rangeArray->TargetClauseLength();
+
+  RefPtr<nsWindow> lastFocusedWindow(mLastFocusedWindow);
+  nsEventStatus status;
+  rv = dispatcher->FlushPendingComposition(status);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionChangeEvent(), FAILED, "
+             "due to FlushPendingComposition() failure",
+             this));
+    return false;
+  }
+
+  if (lastFocusedWindow->IsDestroyed() ||
+      lastFocusedWindow != mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionChangeEvent(), FAILED, the "
+             "focused widget was destroyed/changed by "
+             "compositionchange event",
+             this));
+    return false;
+  }
+  return true;
+}
+
+bool IMContextWrapper::DispatchCompositionCommitEvent(
+    GtkIMContext* aContext, const nsAString* aCommitString) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p DispatchCompositionCommitEvent(aContext=0x%p, "
+           "aCommitString=0x%p, (\"%s\"))",
+           this, aContext, aCommitString,
+           aCommitString ? NS_ConvertUTF16toUTF8(*aCommitString).get() : ""));
+
+  if (!mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionCommitEvent(), FAILED, "
+             "there are no focused window in this module",
+             this));
+    return false;
+  }
+
+  // TODO: We need special care to handle request to commit composition
+  //       by content while we're committing composition because we have
+  //       commit string information now but IME may not have composition
+  //       anymore.  Therefore, we may not be able to handle commit as
+  //       expected.  However, this is rare case because this situation
+  //       never occurs with remote content.  So, it's okay to fix this
+  //       issue later.  (Perhaps, TextEventDisptcher should do it for
+  //       all platforms.  E.g., creating WillCommitComposition()?)
+  RefPtr<nsWindow> lastFocusedWindow(mLastFocusedWindow);
+  RefPtr<TextEventDispatcher> dispatcher;
+  if (!IsComposing() &&
+      !StaticPrefs::intl_ime_use_composition_events_for_insert_text()) {
+    if (!aCommitString || aCommitString->IsEmpty()) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   DispatchCompositionCommitEvent(), FAILED, "
+               "did nothing due to inserting empty string without composition",
+               this));
+      return true;
+    }
+    if (MOZ_UNLIKELY(!EnsureToCacheContentSelection())) {
+      MOZ_LOG(gIMELog, LogLevel::Warning,
+              ("0x%p   DispatchCompositionCommitEvent(), Warning, "
+               "Failed to cache selection before dispatching "
+               "eContentCommandInsertText event",
+               this));
+    }
+    if (!MaybeDispatchKeyEventAsProcessedByIME(eContentCommandInsertText)) {
+      MOZ_LOG(gIMELog, LogLevel::Warning,
+              ("0x%p   DispatchCompositionCommitEvent(), Warning, "
+               "MaybeDispatchKeyEventAsProcessedByIME() returned false",
+               this));
+      return false;
+    }
+    // Emulate selection until receiving actual selection range.  This is
+    // important for OnSelectionChange.  If selection is not changed by web
+    // apps, i.e., selection range is same as what selection expects, we
+    // shouldn't reset IME because the trigger of causing this commit may be an
+    // input for next composition and we shouldn't cancel it.
+    if (mContentSelection.isSome()) {
+      mContentSelection->Collapse(
+          (mContentSelection->HasRange()
+               ? mContentSelection->OffsetAndDataRef().StartOffset()
+               : mCompositionStart) +
+          aCommitString->Length());
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   DispatchCompositionCommitEvent(), mContentSelection=%s",
+               this, ToString(mContentSelection).c_str()));
+    }
+    MOZ_ASSERT(!dispatcher);
+  } else {
+    if (!IsComposing()) {
+      if (!aCommitString || aCommitString->IsEmpty()) {
+        MOZ_LOG(gIMELog, LogLevel::Error,
+                ("0x%p   DispatchCompositionCommitEvent(), FAILED, "
+                 "there is no composition and empty commit string",
+                 this));
+        return true;
+      }
+      MOZ_LOG(gIMELog, LogLevel::Debug,
+              ("0x%p   DispatchCompositionCommitEvent(), "
+               "the composition wasn't started, force starting...",
+               this));
+      if (!DispatchCompositionStart(aContext)) {
+        return false;
+      }
+    }
+    // If this commit caused by a key press, we need to dispatch eKeyDown or
+    // eKeyUp before dispatching composition events.
+    else if (!MaybeDispatchKeyEventAsProcessedByIME(
+                 aCommitString ? eCompositionCommit : eCompositionCommitAsIs)) {
+      MOZ_LOG(gIMELog, LogLevel::Warning,
+              ("0x%p   DispatchCompositionCommitEvent(), Warning, "
+               "MaybeDispatchKeyEventAsProcessedByIME() returned false",
+               this));
+      mCompositionState = eCompositionState_NotComposing;
+      return false;
+    }
+
+    dispatcher = GetTextEventDispatcher();
+    MOZ_ASSERT(dispatcher);
+    nsresult rv = dispatcher->BeginNativeInputTransaction();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   DispatchCompositionCommitEvent(), FAILED, "
+               "due to BeginNativeInputTransaction() failure",
+               this));
+      return false;
+    }
+
+    // Emulate selection until receiving actual selection range.
+    const uint32_t offsetToPutCaret =
+        mCompositionStart + (aCommitString
+                                 ? aCommitString->Length()
+                                 : mDispatchedCompositionString.Length());
+    if (mContentSelection.isSome()) {
+      mContentSelection->Collapse(offsetToPutCaret);
+    } else {
+      // TODO: We should guarantee that there should be at least fake selection
+      //       for IME at here.  Then, we can keep the last writing mode.
+      mContentSelection.emplace(offsetToPutCaret, WritingMode());
+    }
+  }
+
+  mCompositionState = eCompositionState_NotComposing;
+  // Reset dead key sequence too because GTK doesn't support dead key chain
+  // (i.e., a key press doesn't cause both producing some characters and
+  // restarting new dead key sequence at one time).  So, committing
+  // composition means end of a dead key sequence.
+  mMaybeInDeadKeySequence = false;
+  mCompositionStart = UINT32_MAX;
+  mCompositionTargetRange.Clear();
+  mDispatchedCompositionString.Truncate();
+  mSelectedStringRemovedByComposition.Truncate();
+
+  if (!dispatcher) {
+    MOZ_ASSERT(aCommitString);
+    MOZ_ASSERT(!aCommitString->IsEmpty());
+    nsEventStatus status = nsEventStatus_eIgnore;
+    WidgetContentCommandEvent insertTextEvent(true, eContentCommandInsertText,
+                                              lastFocusedWindow);
+    insertTextEvent.mString.emplace(*aCommitString);
+    lastFocusedWindow->DispatchEvent(&insertTextEvent, status);
+
+    if (!insertTextEvent.mSucceeded) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   DispatchCompositionChangeEvent(), FAILED, inserting "
+               "text failed",
+               this));
+      return false;
+    }
+  } else {
+    nsEventStatus status = nsEventStatus_eIgnore;
+    nsresult rv = dispatcher->CommitComposition(status, aCommitString);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   DispatchCompositionChangeEvent(), FAILED, "
+               "due to CommitComposition() failure",
+               this));
+      return false;
+    }
+  }
+
+  if (lastFocusedWindow->IsDestroyed() ||
+      lastFocusedWindow != mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DispatchCompositionCommitEvent(), FAILED, "
+             "the focused widget was destroyed/changed by "
+             "compositioncommit event",
+             this));
+    return false;
+  }
+
+  return true;
+}
+
+already_AddRefed<TextRangeArray> IMContextWrapper::CreateTextRangeArray(
+    GtkIMContext* aContext, const nsAString& aCompositionString) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p CreateTextRangeArray(aContext=0x%p, "
+           "aCompositionString=\"%s\" (Length()=%zu))",
+           this, aContext, NS_ConvertUTF16toUTF8(aCompositionString).get(),
+           aCompositionString.Length()));
+
+  RefPtr<TextRangeArray> textRangeArray = new TextRangeArray();
+
+  gchar* preedit_string;
+  gint cursor_pos_in_chars;
+  PangoAttrList* feedback_list;
+  gtk_im_context_get_preedit_string(aContext, &preedit_string, &feedback_list,
+                                    &cursor_pos_in_chars);
+  if (!preedit_string || !*preedit_string) {
+    if (!aCompositionString.IsEmpty()) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   CreateTextRangeArray(), FAILED, due to "
+               "preedit_string is null",
+               this));
+    }
+    pango_attr_list_unref(feedback_list);
+    g_free(preedit_string);
+    return textRangeArray.forget();
+  }
+
+  // Convert caret offset from offset in characters to offset in UTF-16
+  // string.  If we couldn't proper offset in UTF-16 string, we should
+  // assume that the caret is at the end of the composition string.
+  uint32_t caretOffsetInUTF16 = aCompositionString.Length();
+  if (NS_WARN_IF(cursor_pos_in_chars < 0)) {
+    // Note that this case is undocumented.  We should assume that the
+    // caret is at the end of the composition string.
+  } else if (cursor_pos_in_chars == 0) {
+    caretOffsetInUTF16 = 0;
+  } else {
+    gchar* charAfterCaret =
+        g_utf8_offset_to_pointer(preedit_string, cursor_pos_in_chars);
+    if (NS_WARN_IF(!charAfterCaret)) {
+      MOZ_LOG(gIMELog, LogLevel::Warning,
+              ("0x%p   CreateTextRangeArray(), failed to get UTF-8 "
+               "string before the caret (cursor_pos_in_chars=%d)",
+               this, cursor_pos_in_chars));
+    } else {
+      glong caretOffset = 0;
+      gunichar2* utf16StrBeforeCaret =
+          g_utf8_to_utf16(preedit_string, charAfterCaret - preedit_string,
+                          nullptr, &caretOffset, nullptr);
+      if (NS_WARN_IF(!utf16StrBeforeCaret) || NS_WARN_IF(caretOffset < 0)) {
+        MOZ_LOG(gIMELog, LogLevel::Warning,
+                ("0x%p   CreateTextRangeArray(), WARNING, failed to "
+                 "convert to UTF-16 string before the caret "
+                 "(cursor_pos_in_chars=%d, caretOffset=%ld)",
+                 this, cursor_pos_in_chars, caretOffset));
+      } else {
+        caretOffsetInUTF16 = static_cast<uint32_t>(caretOffset);
+        uint32_t compositionStringLength = aCompositionString.Length();
+        if (NS_WARN_IF(caretOffsetInUTF16 > compositionStringLength)) {
+          MOZ_LOG(gIMELog, LogLevel::Warning,
+                  ("0x%p   CreateTextRangeArray(), WARNING, "
+                   "caretOffsetInUTF16=%u is larger than "
+                   "compositionStringLength=%u",
+                   this, caretOffsetInUTF16, compositionStringLength));
+          caretOffsetInUTF16 = compositionStringLength;
+        }
+      }
+      if (utf16StrBeforeCaret) {
+        g_free(utf16StrBeforeCaret);
+      }
+    }
+  }
+
+  PangoAttrIterator* iter;
+  iter = pango_attr_list_get_iterator(feedback_list);
+  if (!iter) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   CreateTextRangeArray(), FAILED, iterator couldn't "
+             "be allocated",
+             this));
+    pango_attr_list_unref(feedback_list);
+    g_free(preedit_string);
+    return textRangeArray.forget();
+  }
+
+  uint32_t minOffsetOfClauses = aCompositionString.Length();
+  uint32_t maxOffsetOfClauses = 0;
+  do {
+    TextRange range;
+    if (!SetTextRange(iter, preedit_string, caretOffsetInUTF16, range)) {
+      continue;
+    }
+    MOZ_ASSERT(range.Length());
+    minOffsetOfClauses = std::min(minOffsetOfClauses, range.mStartOffset);
+    maxOffsetOfClauses = std::max(maxOffsetOfClauses, range.mEndOffset);
+    textRangeArray->AppendElement(range);
+  } while (pango_attr_iterator_next(iter));
+
+  // If the IME doesn't define clause from the start of the composition,
+  // we should insert dummy clause information since TextRangeArray assumes
+  // that there must be a clause whose start is 0 when there is one or
+  // more clauses.
+  if (minOffsetOfClauses) {
+    TextRange dummyClause;
+    dummyClause.mStartOffset = 0;
+    dummyClause.mEndOffset = minOffsetOfClauses;
+    dummyClause.mRangeType = TextRangeType::eRawClause;
+    textRangeArray->InsertElementAt(0, dummyClause);
+    maxOffsetOfClauses = std::max(maxOffsetOfClauses, dummyClause.mEndOffset);
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   CreateTextRangeArray(), inserting a dummy clause "
+             "at the beginning of the composition string mStartOffset=%u, "
+             "mEndOffset=%u, mRangeType=%s",
+             this, dummyClause.mStartOffset, dummyClause.mEndOffset,
+             ToChar(dummyClause.mRangeType)));
+  }
+
+  // If the IME doesn't define clause at end of the composition, we should
+  // insert dummy clause information since TextRangeArray assumes that there
+  // must be a clase whose end is the length of the composition string when
+  // there is one or more clauses.
+  if (!textRangeArray->IsEmpty() &&
+      maxOffsetOfClauses < aCompositionString.Length()) {
+    TextRange dummyClause;
+    dummyClause.mStartOffset = maxOffsetOfClauses;
+    dummyClause.mEndOffset = aCompositionString.Length();
+    dummyClause.mRangeType = TextRangeType::eRawClause;
+    textRangeArray->AppendElement(dummyClause);
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   CreateTextRangeArray(), inserting a dummy clause "
+             "at the end of the composition string mStartOffset=%u, "
+             "mEndOffset=%u, mRangeType=%s",
+             this, dummyClause.mStartOffset, dummyClause.mEndOffset,
+             ToChar(dummyClause.mRangeType)));
+  }
+
+  TextRange range;
+  range.mStartOffset = range.mEndOffset = caretOffsetInUTF16;
+  range.mRangeType = TextRangeType::eCaret;
+  textRangeArray->AppendElement(range);
+  MOZ_LOG(
+      gIMELog, LogLevel::Debug,
+      ("0x%p   CreateTextRangeArray(), mStartOffset=%u, "
+       "mEndOffset=%u, mRangeType=%s",
+       this, range.mStartOffset, range.mEndOffset, ToChar(range.mRangeType)));
+
+  pango_attr_iterator_destroy(iter);
+  pango_attr_list_unref(feedback_list);
+  g_free(preedit_string);
+
+  return textRangeArray.forget();
+}
+
+/* static */
+nscolor IMContextWrapper::ToNscolor(PangoAttrColor* aPangoAttrColor) {
+  PangoColor& pangoColor = aPangoAttrColor->color;
+  uint8_t r = pangoColor.red / 0x100;
+  uint8_t g = pangoColor.green / 0x100;
+  uint8_t b = pangoColor.blue / 0x100;
+  return NS_RGB(r, g, b);
+}
+
+bool IMContextWrapper::SetTextRange(PangoAttrIterator* aPangoAttrIter,
+                                    const gchar* aUTF8CompositionString,
+                                    uint32_t aUTF16CaretOffset,
+                                    TextRange& aTextRange) const {
+  // Set the range offsets in UTF-16 string.
+  gint utf8ClauseStart, utf8ClauseEnd;
+  pango_attr_iterator_range(aPangoAttrIter, &utf8ClauseStart, &utf8ClauseEnd);
+  if (utf8ClauseStart == utf8ClauseEnd) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   SetTextRange(), FAILED, due to collapsed range", this));
+    return false;
+  }
+
+  if (!utf8ClauseStart) {
+    aTextRange.mStartOffset = 0;
+  } else {
+    glong utf16PreviousClausesLength;
+    gunichar2* utf16PreviousClausesString =
+        g_utf8_to_utf16(aUTF8CompositionString, utf8ClauseStart, nullptr,
+                        &utf16PreviousClausesLength, nullptr);
+
+    if (NS_WARN_IF(!utf16PreviousClausesString)) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   SetTextRange(), FAILED, due to g_utf8_to_utf16() "
+               "failure (retrieving previous string of current clause)",
+               this));
+      return false;
+    }
+
+    aTextRange.mStartOffset = utf16PreviousClausesLength;
+    g_free(utf16PreviousClausesString);
+  }
+
+  glong utf16CurrentClauseLength;
+  gunichar2* utf16CurrentClauseString = g_utf8_to_utf16(
+      aUTF8CompositionString + utf8ClauseStart, utf8ClauseEnd - utf8ClauseStart,
+      nullptr, &utf16CurrentClauseLength, nullptr);
+
+  if (NS_WARN_IF(!utf16CurrentClauseString)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   SetTextRange(), FAILED, due to g_utf8_to_utf16() "
+             "failure (retrieving current clause)",
+             this));
+    return false;
+  }
+
+  // iBus Chewing IME tells us that there is an empty clause at the end of
+  // the composition string but we should ignore it since our code doesn't
+  // assume that there is an empty clause.
+  if (!utf16CurrentClauseLength) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   SetTextRange(), FAILED, due to current clause length "
+             "is 0",
+             this));
+    return false;
+  }
+
+  aTextRange.mEndOffset = aTextRange.mStartOffset + utf16CurrentClauseLength;
+  g_free(utf16CurrentClauseString);
+  utf16CurrentClauseString = nullptr;
+
+  // Set styles
+  TextRangeStyle& style = aTextRange.mRangeStyle;
+
+  // Underline
+  PangoAttrInt* attrUnderline = reinterpret_cast<PangoAttrInt*>(
+      pango_attr_iterator_get(aPangoAttrIter, PANGO_ATTR_UNDERLINE));
+  if (attrUnderline) {
+    switch (attrUnderline->value) {
+      case PANGO_UNDERLINE_NONE:
+        style.mLineStyle = TextRangeStyle::LineStyle::None;
+        break;
+      case PANGO_UNDERLINE_DOUBLE:
+        style.mLineStyle = TextRangeStyle::LineStyle::Double;
+        break;
+      case PANGO_UNDERLINE_ERROR:
+        style.mLineStyle = TextRangeStyle::LineStyle::Wavy;
+        break;
+      case PANGO_UNDERLINE_SINGLE:
+      case PANGO_UNDERLINE_LOW:
+        style.mLineStyle = TextRangeStyle::LineStyle::Solid;
+        break;
+      default:
+        MOZ_LOG(gIMELog, LogLevel::Warning,
+                ("0x%p   SetTextRange(), retrieved unknown underline "
+                 "style: %d",
+                 this, attrUnderline->value));
+        style.mLineStyle = TextRangeStyle::LineStyle::Solid;
+        break;
+    }
+    style.mDefinedStyles |= TextRangeStyle::DEFINED_LINESTYLE;
+
+    // Underline color
+    PangoAttrColor* attrUnderlineColor = reinterpret_cast<PangoAttrColor*>(
+        pango_attr_iterator_get(aPangoAttrIter, PANGO_ATTR_UNDERLINE_COLOR));
+    if (attrUnderlineColor) {
+      style.mUnderlineColor = ToNscolor(attrUnderlineColor);
+      style.mDefinedStyles |= TextRangeStyle::DEFINED_UNDERLINE_COLOR;
+    }
+  } else {
+    style.mLineStyle = TextRangeStyle::LineStyle::None;
+    style.mDefinedStyles |= TextRangeStyle::DEFINED_LINESTYLE;
+  }
+
+  // Don't set colors if they are not specified.  They should be computed by
+  // textframe if only one of the colors are specified.
+
+  // Foreground color (text color)
+  PangoAttrColor* attrForeground = reinterpret_cast<PangoAttrColor*>(
+      pango_attr_iterator_get(aPangoAttrIter, PANGO_ATTR_FOREGROUND));
+  if (attrForeground) {
+    style.mForegroundColor = ToNscolor(attrForeground);
+    style.mDefinedStyles |= TextRangeStyle::DEFINED_FOREGROUND_COLOR;
+  }
+
+  // Background color
+  PangoAttrColor* attrBackground = reinterpret_cast<PangoAttrColor*>(
+      pango_attr_iterator_get(aPangoAttrIter, PANGO_ATTR_BACKGROUND));
+  if (attrBackground) {
+    style.mBackgroundColor = ToNscolor(attrBackground);
+    style.mDefinedStyles |= TextRangeStyle::DEFINED_BACKGROUND_COLOR;
+  }
+
+  /**
+   * We need to judge the meaning of the clause for a11y.  Before we support
+   * IME specific composition string style, we used following rules:
+   *
+   *   1: If attrUnderline and attrForground are specified, we assumed the
+   *      clause is TextRangeType::eSelectedClause.
+   *   2: If only attrUnderline is specified, we assumed the clause is
+   *      TextRangeType::eConvertedClause.
+   *   3: If only attrForground is specified, we assumed the clause is
+   *      TextRangeType::eSelectedRawClause.
+   *   4: If neither attrUnderline nor attrForeground is specified, we assumed
+   *      the clause is TextRangeType::eRawClause.
+   *
+   * However, this rules are odd since there can be two or more selected
+   * clauses.  Additionally, our old rules caused that IME developers/users
+   * cannot specify composition string style as they want.
+   *
+   * So, we shouldn't guess the meaning from its visual style.
+   */
+
+  // If the range covers whole of composition string and the caret is at
+  // the end of the composition string, the range is probably not converted.
+  if (!utf8ClauseStart &&
+      utf8ClauseEnd == static_cast<gint>(strlen(aUTF8CompositionString)) &&
+      aTextRange.mEndOffset == aUTF16CaretOffset) {
+    aTextRange.mRangeType = TextRangeType::eRawClause;
+  }
+  // Typically, the caret is set at the start of the selected clause.
+  // So, if the caret is in the clause, we can assume that the clause is
+  // selected.
+  else if (aTextRange.mStartOffset <= aUTF16CaretOffset &&
+           aTextRange.mEndOffset > aUTF16CaretOffset) {
+    aTextRange.mRangeType = TextRangeType::eSelectedClause;
+  }
+  // Otherwise, we should assume that the clause is converted but not
+  // selected.
+  else {
+    aTextRange.mRangeType = TextRangeType::eConvertedClause;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   SetTextRange(), succeeded, aTextRange= { "
+           "mStartOffset=%u, mEndOffset=%u, mRangeType=%s, mRangeStyle=%s }",
+           this, aTextRange.mStartOffset, aTextRange.mEndOffset,
+           ToChar(aTextRange.mRangeType),
+           GetTextRangeStyleText(aTextRange.mRangeStyle).get()));
+
+  return true;
+}
+
+void IMContextWrapper::SetCursorPosition(GtkIMContext* aContext) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p SetCursorPosition(aContext=0x%p), "
+       "mCompositionTargetRange={ mOffset=%u, mLength=%u }, "
+       "mContentSelection=%s",
+       this, aContext, mCompositionTargetRange.mOffset,
+       mCompositionTargetRange.mLength, ToString(mContentSelection).c_str()));
+
+  bool useCaret = false;
+  if (!mCompositionTargetRange.IsValid()) {
+    if (mContentSelection.isNothing()) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   SetCursorPosition(), FAILED, "
+               "mCompositionTargetRange and mContentSelection are invalid",
+               this));
+      return;
+    }
+    if (!mContentSelection->HasRange()) {
+      MOZ_LOG(gIMELog, LogLevel::Warning,
+              ("0x%p   SetCursorPosition(), FAILED, "
+               "mCompositionTargetRange is invalid and there is no selection",
+               this));
+      return;
+    }
+    useCaret = true;
+  }
+
+  if (!mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   SetCursorPosition(), FAILED, due to no focused "
+             "window",
+             this));
+    return;
+  }
+
+  if (MOZ_UNLIKELY(!aContext)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   SetCursorPosition(), FAILED, due to no context", this));
+    return;
+  }
+
+  WidgetQueryContentEvent queryCaretOrTextRectEvent(
+      true, useCaret ? eQueryCaretRect : eQueryTextRect, mLastFocusedWindow);
+  if (useCaret) {
+    queryCaretOrTextRectEvent.InitForQueryCaretRect(
+        mContentSelection->OffsetAndDataRef().StartOffset());
+  } else {
+    if (mContentSelection->WritingModeRef().IsVertical()) {
+      // For preventing the candidate window to overlap the target
+      // clause, we should set fake (typically, very tall) caret rect.
+      uint32_t length =
+          mCompositionTargetRange.mLength ? mCompositionTargetRange.mLength : 1;
+      queryCaretOrTextRectEvent.InitForQueryTextRect(
+          mCompositionTargetRange.mOffset, length);
+    } else {
+      queryCaretOrTextRectEvent.InitForQueryTextRect(
+          mCompositionTargetRange.mOffset, 1);
+    }
+  }
+  nsEventStatus status;
+  mLastFocusedWindow->DispatchEvent(&queryCaretOrTextRectEvent, status);
+  if (queryCaretOrTextRectEvent.Failed()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   SetCursorPosition(), FAILED, %s was failed", this,
+             useCaret ? "eQueryCaretRect" : "eQueryTextRect"));
+    return;
+  }
+
+  nsWindow* rootWindow =
+      static_cast<nsWindow*>(mLastFocusedWindow->GetTopLevelWidget());
+
+  // Get the position of the rootWindow in screen.
+  LayoutDeviceIntPoint root = rootWindow->WidgetToScreenOffset();
+
+  // Get the position of IM context owner window in screen.
+  LayoutDeviceIntPoint owner = mOwnerWindow->WidgetToScreenOffset();
+
+  // Compute the caret position in the IM owner window.
+  LayoutDeviceIntRect rect =
+      queryCaretOrTextRectEvent.mReply->mRect + root - owner;
+  rect.width = 0;
+  GdkRectangle area = rootWindow->DevicePixelsToGdkRectRoundOut(rect);
+
+  gtk_im_context_set_cursor_location(aContext, &area);
+}
+
+nsresult IMContextWrapper::GetCurrentParagraph(nsAString& aText,
+                                               uint32_t& aCursorPos) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p GetCurrentParagraph(), mCompositionState=%s", this,
+           GetCompositionStateName()));
+
+  if (!mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   GetCurrentParagraph(), FAILED, there are no "
+             "focused window in this module",
+             this));
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  nsEventStatus status;
+
+  uint32_t selOffset = mCompositionStart;
+  uint32_t selLength = mSelectedStringRemovedByComposition.Length();
+
+  // If focused editor doesn't have composition string, we should use
+  // current selection.
+  if (!EditorHasCompositionString()) {
+    // Query cursor position & selection
+    if (NS_WARN_IF(!EnsureToCacheContentSelection())) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   GetCurrentParagraph(), FAILED, due to no "
+               "valid selection information",
+               this));
+      return NS_ERROR_FAILURE;
+    }
+
+    if (mContentSelection.isSome() && mContentSelection->HasRange()) {
+      selOffset = mContentSelection->OffsetAndDataRef().StartOffset();
+      selLength = mContentSelection->OffsetAndDataRef().Length();
+    } else {
+      // If there is no range, let's get all text instead...
+      selOffset = 0u;
+      selLength = INT32_MAX;  // TODO: Change to UINT32_MAX, but see below
+    }
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   GetCurrentParagraph(), selOffset=%u, selLength=%u", this,
+           selOffset, selLength));
+
+  // XXX nsString::Find and nsString::RFind take int32_t for offset, so,
+  //     we cannot support this request when the current offset is larger
+  //     than INT32_MAX.
+  if (selOffset > INT32_MAX || selLength > INT32_MAX ||
+      selOffset + selLength > INT32_MAX) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   GetCurrentParagraph(), FAILED, The selection is "
+             "out of range",
+             this));
+    return NS_ERROR_FAILURE;
+  }
+
+  // Get all text contents of the focused editor
+  WidgetQueryContentEvent queryTextContentEvent(true, eQueryTextContent,
+                                                mLastFocusedWindow);
+  queryTextContentEvent.InitForQueryTextContent(0, UINT32_MAX);
+  mLastFocusedWindow->DispatchEvent(&queryTextContentEvent, status);
+  if (NS_WARN_IF(queryTextContentEvent.Failed())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (selOffset + selLength > queryTextContentEvent.mReply->DataLength()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   GetCurrentParagraph(), FAILED, The selection is "
+             "invalid, queryTextContentEvent={ mReply=%s }",
+             this, ToString(queryTextContentEvent.mReply).c_str()));
+    return NS_ERROR_FAILURE;
+  }
+
+  // Remove composing string and restore the selected string because
+  // GtkEntry doesn't remove selected string until committing, however,
+  // our editor does it.  We should emulate the behavior for IME.
+  nsAutoString textContent(queryTextContentEvent.mReply->DataRef());
+  if (EditorHasCompositionString() &&
+      mDispatchedCompositionString != mSelectedStringRemovedByComposition) {
+    textContent.Replace(mCompositionStart,
+                        mDispatchedCompositionString.Length(),
+                        mSelectedStringRemovedByComposition);
+  }
+
+  // Get only the focused paragraph, by looking for newlines
+  int32_t parStart = 0;
+  if (selOffset > 0) {
+    parStart = Substring(textContent, 0, selOffset - 1).RFind(u"\n") + 1;
+  }
+  int32_t parEnd = textContent.Find(u"\n", selOffset + selLength);
+  if (parEnd < 0) {
+    parEnd = textContent.Length();
+  }
+  aText = nsDependentSubstring(textContent, parStart, parEnd - parStart);
+  aCursorPos = selOffset - uint32_t(parStart);
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Debug,
+      ("0x%p   GetCurrentParagraph(), succeeded, aText=%s, "
+       "aText.Length()=%zu, aCursorPos=%u",
+       this, NS_ConvertUTF16toUTF8(aText).get(), aText.Length(), aCursorPos));
+
+  return NS_OK;
+}
+
+nsresult IMContextWrapper::DeleteText(GtkIMContext* aContext, int32_t aOffset,
+                                      uint32_t aNChars) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p DeleteText(aContext=0x%p, aOffset=%d, aNChars=%u), "
+           "mCompositionState=%s",
+           this, aContext, aOffset, aNChars, GetCompositionStateName()));
+
+  if (!mLastFocusedWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DeleteText(), FAILED, there are no focused window "
+             "in this module",
+             this));
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  if (!aNChars) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DeleteText(), FAILED, aNChars must not be zero", this));
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  RefPtr<nsWindow> lastFocusedWindow(mLastFocusedWindow);
+  nsEventStatus status;
+
+  // First, we should cancel current composition because editor cannot
+  // handle changing selection and deleting text.
+  uint32_t selOffset;
+  bool wasComposing = IsComposing();
+  bool editorHadCompositionString = EditorHasCompositionString();
+  if (wasComposing) {
+    selOffset = mCompositionStart;
+    if (!DispatchCompositionCommitEvent(aContext,
+                                        &mSelectedStringRemovedByComposition)) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   DeleteText(), FAILED, quitting from DeletText", this));
+      return NS_ERROR_FAILURE;
+    }
+  } else {
+    if (NS_WARN_IF(!EnsureToCacheContentSelection())) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   DeleteText(), FAILED, due to no valid selection "
+               "information",
+               this));
+      return NS_ERROR_FAILURE;
+    }
+    if (!mContentSelection->HasRange()) {
+      MOZ_LOG(gIMELog, LogLevel::Debug,
+              ("0x%p   DeleteText(), does nothing, due to no selection range",
+               this));
+      return NS_OK;
+    }
+    selOffset = mContentSelection->OffsetAndDataRef().StartOffset();
+  }
+
+  // Get all text contents of the focused editor
+  WidgetQueryContentEvent queryTextContentEvent(true, eQueryTextContent,
+                                                mLastFocusedWindow);
+  queryTextContentEvent.InitForQueryTextContent(0, UINT32_MAX);
+  mLastFocusedWindow->DispatchEvent(&queryTextContentEvent, status);
+  if (NS_WARN_IF(queryTextContentEvent.Failed())) {
+    return NS_ERROR_FAILURE;
+  }
+  if (queryTextContentEvent.mReply->IsDataEmpty()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DeleteText(), FAILED, there is no contents", this));
+    return NS_ERROR_FAILURE;
+  }
+
+  NS_ConvertUTF16toUTF8 utf8Str(nsDependentSubstring(
+      queryTextContentEvent.mReply->DataRef(), 0, selOffset));
+  glong offsetInUTF8Characters =
+      g_utf8_strlen(utf8Str.get(), utf8Str.Length()) + aOffset;
+  if (offsetInUTF8Characters < 0) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DeleteText(), FAILED, aOffset is too small for "
+             "current cursor pos (computed offset: %ld)",
+             this, offsetInUTF8Characters));
+    return NS_ERROR_FAILURE;
+  }
+
+  AppendUTF16toUTF8(
+      nsDependentSubstring(queryTextContentEvent.mReply->DataRef(), selOffset),
+      utf8Str);
+  glong countOfCharactersInUTF8 =
+      g_utf8_strlen(utf8Str.get(), utf8Str.Length());
+  glong endInUTF8Characters = offsetInUTF8Characters + aNChars;
+  if (countOfCharactersInUTF8 < endInUTF8Characters) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DeleteText(), FAILED, aNChars is too large for "
+             "current contents (content length: %ld, computed end offset: %ld)",
+             this, countOfCharactersInUTF8, endInUTF8Characters));
+    return NS_ERROR_FAILURE;
+  }
+
+  gchar* charAtOffset =
+      g_utf8_offset_to_pointer(utf8Str.get(), offsetInUTF8Characters);
+  gchar* charAtEnd =
+      g_utf8_offset_to_pointer(utf8Str.get(), endInUTF8Characters);
+
+  // Set selection to delete
+  WidgetSelectionEvent selectionEvent(true, eSetSelection, mLastFocusedWindow);
+
+  nsDependentCSubstring utf8StrBeforeOffset(utf8Str, 0,
+                                            charAtOffset - utf8Str.get());
+  selectionEvent.mOffset = NS_ConvertUTF8toUTF16(utf8StrBeforeOffset).Length();
+
+  nsDependentCSubstring utf8DeletingStr(utf8Str, utf8StrBeforeOffset.Length(),
+                                        charAtEnd - charAtOffset);
+  selectionEvent.mLength = NS_ConvertUTF8toUTF16(utf8DeletingStr).Length();
+
+  selectionEvent.mReversed = false;
+  selectionEvent.mExpandToClusterBoundary = false;
+  lastFocusedWindow->DispatchEvent(&selectionEvent, status);
+
+  if (!selectionEvent.mSucceeded || lastFocusedWindow != mLastFocusedWindow ||
+      lastFocusedWindow->Destroyed()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DeleteText(), FAILED, setting selection caused "
+             "focus change or window destroyed",
+             this));
+    return NS_ERROR_FAILURE;
+  }
+
+  // If this deleting text caused by a key press, we need to dispatch
+  // eKeyDown or eKeyUp before dispatching eContentCommandDelete event.
+  if (!MaybeDispatchKeyEventAsProcessedByIME(eContentCommandDelete)) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   DeleteText(), Warning, "
+             "MaybeDispatchKeyEventAsProcessedByIME() returned false",
+             this));
+    return NS_ERROR_FAILURE;
+  }
+
+  // Delete the selection
+  WidgetContentCommandEvent contentCommandEvent(true, eContentCommandDelete,
+                                                mLastFocusedWindow);
+  mLastFocusedWindow->DispatchEvent(&contentCommandEvent, status);
+
+  if (!contentCommandEvent.mSucceeded ||
+      lastFocusedWindow != mLastFocusedWindow ||
+      lastFocusedWindow->Destroyed()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   DeleteText(), FAILED, deleting the selection caused "
+             "focus change or window destroyed",
+             this));
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!wasComposing) {
+    return NS_OK;
+  }
+
+  // Restore the composition at new caret position.
+  if (!DispatchCompositionStart(aContext)) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Error,
+        ("0x%p   DeleteText(), FAILED, resterting composition start", this));
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!editorHadCompositionString) {
+    return NS_OK;
+  }
+
+  nsAutoString compositionString;
+  GetCompositionString(aContext, compositionString);
+  if (!DispatchCompositionChangeEvent(aContext, compositionString)) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Error,
+        ("0x%p   DeleteText(), FAILED, restoring composition string", this));
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+bool IMContextWrapper::EnsureToCacheContentSelection(
+    nsAString* aSelectedString) {
+  if (aSelectedString) {
+    aSelectedString->Truncate();
+  }
+
+  if (mContentSelection.isSome()) {
+    if (mContentSelection->HasRange() && aSelectedString) {
+      aSelectedString->Assign(mContentSelection->OffsetAndDataRef().DataRef());
+    }
+    return true;
+  }
+
+  RefPtr<nsWindow> dispatcherWindow =
+      mLastFocusedWindow ? mLastFocusedWindow : mOwnerWindow;
+  if (NS_WARN_IF(!dispatcherWindow)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p EnsureToCacheContentSelection(), FAILED, due to "
+             "no focused window",
+             this));
+    return false;
+  }
+
+  nsEventStatus status;
+  WidgetQueryContentEvent querySelectedTextEvent(true, eQuerySelectedText,
+                                                 dispatcherWindow);
+  dispatcherWindow->DispatchEvent(&querySelectedTextEvent, status);
+  if (NS_WARN_IF(querySelectedTextEvent.Failed())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p EnsureToCacheContentSelection(), FAILED, due to "
+             "failure of query selection event",
+             this));
+    return false;
+  }
+
+  mContentSelection = Some(ContentSelection(querySelectedTextEvent));
+  if (mContentSelection->HasRange()) {
+    if (!mContentSelection->OffsetAndDataRef().IsDataEmpty() &&
+        aSelectedString) {
+      aSelectedString->Assign(querySelectedTextEvent.mReply->DataRef());
+    }
+  }
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Debug,
+      ("0x%p EnsureToCacheContentSelection(), Succeeded, mContentSelection=%s",
+       this, ToString(mContentSelection).c_str()));
+  return true;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/gtk/IMContextWrapper.h b/widget/gtk/IMContextWrapper.h
new file mode 100644
index 0000000000..213c5ce8d3
--- /dev/null
+++ b/widget/gtk/IMContextWrapper.h
@@ -0,0 +1,692 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef IMContextWrapper_h_
+#define IMContextWrapper_h_
+
+#include <gdk/gdk.h>
+#include <gtk/gtk.h>
+
+#include "nsString.h"
+#include "nsCOMPtr.h"
+#include "nsTArray.h"
+#include "nsIWidget.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/ContentData.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/TextEventDispatcherListener.h"
+#include "mozilla/WritingModes.h"
+#include "mozilla/GUniquePtr.h"
+#include "mozilla/widget/IMEData.h"
+
+class nsWindow;
+
+namespace mozilla {
+namespace widget {
+
+/**
+ * KeyHandlingState is result of IMContextWrapper::OnKeyEvent().
+ */
+enum class KeyHandlingState {
+  // The native key event has not been handled by IMContextWrapper.
+  eNotHandled,
+  // The native key event was handled by IMContextWrapper.
+  eHandled,
+  // The native key event has not been handled by IMContextWrapper,
+  // but eKeyDown or eKeyUp event has been dispatched.
+  eNotHandledButEventDispatched,
+  // The native key event has not been handled by IMContextWrapper,
+  // but eKeyDown or eKeyUp event has been dispatched and consumed.
+  eNotHandledButEventConsumed,
+};
+
+class IMContextWrapper final : public TextEventDispatcherListener {
+ public:
+  // TextEventDispatcherListener implementation
+  NS_DECL_ISUPPORTS
+
+  NS_IMETHOD NotifyIME(TextEventDispatcher* aTextEventDispatcher,
+                       const IMENotification& aNotification) override;
+  NS_IMETHOD_(IMENotificationRequests) GetIMENotificationRequests() override;
+  NS_IMETHOD_(void)
+  OnRemovedFrom(TextEventDispatcher* aTextEventDispatcher) override;
+  NS_IMETHOD_(void)
+  WillDispatchKeyboardEvent(TextEventDispatcher* aTextEventDispatcher,
+                            WidgetKeyboardEvent& aKeyboardEvent,
+                            uint32_t aIndexOfKeypress, void* aData) override;
+
+ public:
+  // aOwnerWindow is a pointer of the owner window.  When aOwnerWindow is
+  // destroyed, the related IME contexts are released (i.e., IME cannot be
+  // used with the instance after that).
+  explicit IMContextWrapper(nsWindow* aOwnerWindow);
+
+  // Called when the process is being shut down.
+  static void Shutdown();
+
+  // "Enabled" means the users can use all IMEs.
+  // I.e., the focus is in the normal editors.
+  bool IsEnabled() const;
+
+  // OnFocusWindow is a notification that aWindow is going to be focused.
+  void OnFocusWindow(nsWindow* aWindow);
+  // OnBlurWindow is a notification that aWindow is going to be unfocused.
+  void OnBlurWindow(nsWindow* aWindow);
+  // OnDestroyWindow is a notification that aWindow is going to be destroyed.
+  void OnDestroyWindow(nsWindow* aWindow);
+  // OnFocusChangeInGecko is a notification that an editor gets focus.
+  void OnFocusChangeInGecko(bool aFocus);
+  // OnSelectionChange is a notification that selection (caret) is changed
+  // in the focused editor.
+  void OnSelectionChange(nsWindow* aCaller,
+                         const IMENotification& aIMENotification);
+  // OnThemeChanged is called when desktop theme is changed.
+  static void OnThemeChanged();
+
+  /**
+   * OnKeyEvent() is called when aWindow gets a native key press event or a
+   * native key release event.  If this returns true, the key event was
+   * filtered by IME.  Otherwise, this returns false.
+   * NOTE: When the native key press event starts composition, this returns
+   *       true but dispatches an eKeyDown event or eKeyUp event before
+   *       dispatching composition events or content command event.
+   *
+   * @param aWindow                       A window on which user operate the
+   *                                      key.
+   * @param aEvent                        A native key press or release
+   *                                      event.
+   * @param aKeyboardEventWasDispatched   true if eKeyDown or eKeyUp event
+   *                                      for aEvent has already been
+   *                                      dispatched.  In this case,
+   *                                      this class doesn't dispatch
+   *                                      keyboard event anymore.
+   */
+  KeyHandlingState OnKeyEvent(nsWindow* aWindow, GdkEventKey* aEvent,
+                              bool aKeyboardEventWasDispatched = false);
+
+  // IME related nsIWidget methods.
+  nsresult EndIMEComposition(nsWindow* aCaller);
+  void SetInputContext(nsWindow* aCaller, const InputContext* aContext,
+                       const InputContextAction* aAction);
+  InputContext GetInputContext();
+  void OnUpdateComposition();
+  void OnLayoutChange();
+
+  // Set GdkWindow associated with IM context.
+  // It can be null which disables context operations.
+  void SetGdkWindow(GdkWindow* aGdkWindow);
+
+  TextEventDispatcher* GetTextEventDispatcher();
+
+  // TODO: Typically, new IM comes every several years.  And now, our code
+  //       becomes really IM behavior dependent.  So, perhaps, we need prefs
+  //       to control related flags for IM developers.
+  enum class IMContextID : uint8_t {
+    Fcitx,  // 4.x or earlier
+    Fcitx5,
+    IBus,
+    IIIMF,
+    Scim,
+    Uim,
+    Wayland,
+    Unknown,
+  };
+
+  friend std::ostream& operator<<(std::ostream& aStream,
+                                  const IMContextID& aIMContextID) {
+    switch (aIMContextID) {
+      case IMContextID::Fcitx:
+        return aStream << "Fcitx";
+      case IMContextID::Fcitx5:
+        return aStream << "Fcitx5";
+      case IMContextID::IBus:
+        return aStream << "IBus";
+      case IMContextID::IIIMF:
+        return aStream << "IIIMF";
+      case IMContextID::Scim:
+        return aStream << "Scim";
+      case IMContextID::Uim:
+        return aStream << "Uim";
+      case IMContextID::Wayland:
+        return aStream << "Wayland";
+      case IMContextID::Unknown:
+        return aStream << "Unknown";
+    }
+    MOZ_ASSERT_UNREACHABLE("Add new case for the new IM support");
+    return aStream << "Unknown";
+  }
+
+  /**
+   * GetIMName() returns IM name associated with mContext.  If the context is
+   * xim, this look for actual engine from XMODIFIERS environment variable.
+   */
+  nsDependentCSubstring GetIMName() const;
+
+  /**
+   * GetWaitingSynthesizedKeyPressHardwareKeyCode() returns hardware_keycode
+   * value of last handled GDK_KEY_PRESS event which is probable handled by
+   * IME asynchronously and we have not received synthesized GDK_KEY_PRESS
+   * event yet.
+   */
+  static guint16 GetWaitingSynthesizedKeyPressHardwareKeyCode() {
+    return sWaitingSynthesizedKeyPressHardwareKeyCode;
+  }
+
+ protected:
+  ~IMContextWrapper();
+
+  /**
+   * SetInputPurposeAndInputHints() sets input-purpose and input-hints of
+   * current IM context to the values computed with mInputContext.
+   */
+  void SetInputPurposeAndInputHints();
+
+  // Owner of an instance of this class. This should be top level window.
+  // The owner window must release the contexts when it's destroyed because
+  // the IME contexts need the native window.  If OnDestroyWindow() is called
+  // with the owner window, it'll release IME contexts.  Otherwise, it'll
+  // just clean up any existing composition if it's related to the destroying
+  // child window.
+  nsWindow* mOwnerWindow;
+
+  // A last focused window in this class's context.
+  nsWindow* mLastFocusedWindow;
+
+  // Actual context. This is used for handling the user's input.
+  GtkIMContext* mContext;
+
+  // mSimpleContext is used for the password field and
+  // the |ime-mode: disabled;| editors if sUseSimpleContext is true.
+  // These editors disable IME.  But dead keys should work.  Fortunately,
+  // the simple IM context of GTK2 support only them.
+  GtkIMContext* mSimpleContext;
+
+  // mDummyContext is a dummy context and will be used in Focus()
+  // when the state of mEnabled means disabled.  This context's IME state is
+  // always "closed", so it closes IME forcedly.
+  GtkIMContext* mDummyContext;
+
+  // mComposingContext is not nullptr while one of mContext, mSimpleContext
+  // and mDummyContext has composition.
+  // XXX: We don't assume that two or more context have composition same time.
+  GtkIMContext* mComposingContext;
+
+  // IME enabled state and other things defined in InputContext.
+  // Use following helper methods if you don't need the detail of the status.
+  InputContext mInputContext;
+
+  // mCompositionStart is the start offset of the composition string in the
+  // current content.  When <textarea> or <input> have focus, it means offset
+  // from the first character of them.  When a HTML editor has focus, it
+  // means offset from the first character of the root element of the editor.
+  uint32_t mCompositionStart;
+
+  // mDispatchedCompositionString is the latest composition string which
+  // was dispatched by compositionupdate event.
+  nsString mDispatchedCompositionString;
+
+  // mSelectedStringRemovedByComposition is the selected string which was
+  // removed by first compositionchange event.
+  nsString mSelectedStringRemovedByComposition;
+
+  // OnKeyEvent() temporarily sets mProcessingKeyEvent to the given native
+  // event.
+  GdkEventKey* mProcessingKeyEvent;
+
+  /**
+   * GdkEventKeyQueue stores *copy* of GdkEventKey instances.  However, this
+   * must be safe to our usecase since it has |time| and the value should not
+   * be same as older event.
+   */
+  class GdkEventKeyQueue final {
+   public:
+    ~GdkEventKeyQueue() { Clear(); }
+
+    void Clear() { mEvents.Clear(); }
+
+    /**
+     * PutEvent() puts new event into the queue.
+     */
+    void PutEvent(const GdkEventKey* aEvent) {
+      GdkEventKey* newEvent = reinterpret_cast<GdkEventKey*>(
+          gdk_event_copy(reinterpret_cast<const GdkEvent*>(aEvent)));
+      newEvent->state &= GDK_MODIFIER_MASK;
+      mEvents.AppendElement(newEvent);
+    }
+
+    /**
+     * RemoveEvent() removes oldest same event and its preceding events
+     * from the queue.
+     */
+    void RemoveEvent(const GdkEventKey* aEvent) {
+      size_t index = IndexOf(aEvent);
+      if (NS_WARN_IF(index == GdkEventKeyQueue::NoIndex())) {
+        return;
+      }
+      mEvents.RemoveElementAt(index);
+    }
+
+    /**
+     * Return corresponding GDK_KEY_PRESS event for aEvent.  aEvent must be a
+     * GDK_KEY_RELEASE event.
+     */
+    const GdkEventKey* GetCorrespondingKeyPressEvent(
+        const GdkEventKey* aEvent) const {
+      MOZ_ASSERT(aEvent->type == GDK_KEY_RELEASE);
+      for (const GUniquePtr<GdkEventKey>& pendingKeyEvent : mEvents) {
+        if (pendingKeyEvent->type == GDK_KEY_PRESS &&
+            aEvent->hardware_keycode == pendingKeyEvent->hardware_keycode) {
+          return pendingKeyEvent.get();
+        }
+      }
+      return nullptr;
+    }
+
+    /**
+     * FirstEvent() returns oldest event in the queue.
+     */
+    GdkEventKey* GetFirstEvent() const {
+      if (mEvents.IsEmpty()) {
+        return nullptr;
+      }
+      return mEvents[0].get();
+    }
+
+    bool IsEmpty() const { return mEvents.IsEmpty(); }
+
+    static size_t NoIndex() { return nsTArray<GdkEventKey*>::NoIndex; }
+    size_t Length() const { return mEvents.Length(); }
+    size_t IndexOf(const GdkEventKey* aEvent) const {
+      static_assert(!(GDK_MODIFIER_MASK & (1 << 24)),
+                    "We assumes 25th bit is used by some IM, but used by GDK");
+      static_assert(!(GDK_MODIFIER_MASK & (1 << 25)),
+                    "We assumes 26th bit is used by some IM, but used by GDK");
+      for (size_t i = 0; i < mEvents.Length(); i++) {
+        GdkEventKey* event = mEvents[i].get();
+        // It must be enough to compare only type, time, keyval and
+        // part of state.   Note that we cannot compaire two events
+        // simply since IME may have changed unused bits of state.
+        if (event->time == aEvent->time) {
+          if (NS_WARN_IF(event->type != aEvent->type) ||
+              NS_WARN_IF(event->keyval != aEvent->keyval) ||
+              NS_WARN_IF(event->state != (aEvent->state & GDK_MODIFIER_MASK))) {
+            continue;
+          }
+        }
+        return i;
+      }
+      return GdkEventKeyQueue::NoIndex();
+    }
+
+   private:
+    nsTArray<GUniquePtr<GdkEventKey>> mEvents;
+  };
+  // OnKeyEvent() append mPostingKeyEvents when it believes that a key event
+  // is posted to other IME process.
+  GdkEventKeyQueue mPostingKeyEvents;
+
+  static guint16 sWaitingSynthesizedKeyPressHardwareKeyCode;
+
+  struct Range {
+    uint32_t mOffset;
+    uint32_t mLength;
+
+    Range() : mOffset(UINT32_MAX), mLength(UINT32_MAX) {}
+
+    bool IsValid() const { return mOffset != UINT32_MAX; }
+    void Clear() {
+      mOffset = UINT32_MAX;
+      mLength = UINT32_MAX;
+    }
+  };
+
+  // current target offset and length of IME composition
+  Range mCompositionTargetRange;
+
+  // mCompositionState indicates current status of composition.
+  enum eCompositionState : uint8_t {
+    eCompositionState_NotComposing,
+    eCompositionState_CompositionStartDispatched,
+    eCompositionState_CompositionChangeEventDispatched
+  };
+  eCompositionState mCompositionState;
+
+  bool IsComposing() const {
+    return (mCompositionState != eCompositionState_NotComposing);
+  }
+
+  bool IsComposingOn(GtkIMContext* aContext) const {
+    return IsComposing() && mComposingContext == aContext;
+  }
+
+  bool IsComposingOnCurrentContext() const {
+    return IsComposingOn(GetCurrentContext());
+  }
+
+  bool EditorHasCompositionString() {
+    return (mCompositionState ==
+            eCompositionState_CompositionChangeEventDispatched);
+  }
+
+  /**
+   * Checks if aContext is valid context for handling composition.
+   *
+   * @param aContext          An IM context which is specified by native
+   *                          composition events.
+   * @return                  true if the context is valid context for
+   *                          handling composition.  Otherwise, false.
+   */
+  bool IsValidContext(GtkIMContext* aContext) const;
+
+  const char* GetCompositionStateName() {
+    switch (mCompositionState) {
+      case eCompositionState_NotComposing:
+        return "NotComposing";
+      case eCompositionState_CompositionStartDispatched:
+        return "CompositionStartDispatched";
+      case eCompositionState_CompositionChangeEventDispatched:
+        return "CompositionChangeEventDispatched";
+      default:
+        return "InvaildState";
+    }
+  }
+
+  // mIMContextID indicates the ID of mContext.  This is actually indicates
+  // IM which user selected.
+  IMContextID mIMContextID;
+
+  // If mContentSelection is Nothing, it means that
+  // EnsureToCacheContentSelection failed to get selection or just not caching
+  // the selection.
+  Maybe<ContentSelection> mContentSelection;
+
+  /**
+   * Return true if mContentSelection is set to some.  Otherwise, false.
+   */
+  bool EnsureToCacheContentSelection(nsAString* aSelectedString = nullptr);
+
+  enum class IMEFocusState : uint8_t {
+    // IME has focus
+    Focused,
+    // IME was blurred
+    Blurred,
+    // IME was blurred without a focus change
+    BlurredWithoutFocusChange,
+  };
+  friend std::ostream& operator<<(std::ostream& aStream, IMEFocusState aState) {
+    switch (aState) {
+      case IMEFocusState::Focused:
+        return aStream << "IMEFocusState::Focused";
+      case IMEFocusState::Blurred:
+        return aStream << "IMEFocusState::Blurred";
+      case IMEFocusState::BlurredWithoutFocusChange:
+        return aStream << "IMEFocusState::BlurredWithoutFocusChange";
+      default:
+        MOZ_ASSERT_UNREACHABLE("Invalid value");
+        return aStream << "<illegal value>";
+    }
+  }
+  IMEFocusState mIMEFocusState = IMEFocusState::Blurred;
+
+  // mFallbackToKeyEvent is set to false when this class starts to handle
+  // a native key event (at that time, mProcessingKeyEvent is set to the
+  // native event).  If active IME just commits composition with a character
+  // which is produced by the key with current keyboard layout, this is set
+  // to true.
+  bool mFallbackToKeyEvent;
+  // mKeyboardEventWasDispatched is used by OnKeyEvent() and
+  // MaybeDispatchKeyEventAsProcessedByIME().
+  // MaybeDispatchKeyEventAsProcessedByIME() dispatches an eKeyDown or
+  // eKeyUp event event if the composition is caused by a native
+  // key press event.  If this is true, a keyboard event has been dispatched
+  // for the native event.  If so, MaybeDispatchKeyEventAsProcessedByIME()
+  // won't dispatch keyboard event anymore.
+  bool mKeyboardEventWasDispatched;
+  // Whether the keyboard event which as dispatched at setting
+  // mKeyboardEventWasDispatched to true was consumed or not.
+  bool mKeyboardEventWasConsumed;
+  // mIsDeletingSurrounding is true while OnDeleteSurroundingNative() is
+  // trying to delete the surrounding text.
+  bool mIsDeletingSurrounding;
+  // mLayoutChanged is true after OnLayoutChange() is called.  This is reset
+  // when eCompositionChange is being dispatched.
+  bool mLayoutChanged;
+  // mSetCursorPositionOnKeyEvent true when caret rect or position is updated
+  // with no composition.  If true, we update candidate window position
+  // before key down
+  bool mSetCursorPositionOnKeyEvent;
+  // mPendingResettingIMContext becomes true if selection change notification
+  // is received during composition but the selection change occurred before
+  // starting the composition.  In such case, we cannot notify IME of
+  // selection change during composition because we don't want to commit
+  // the composition in such case.  However, we should notify IME of the
+  // selection change after the composition is committed.
+  bool mPendingResettingIMContext;
+  // mRetrieveSurroundingSignalReceived is true after "retrieve_surrounding"
+  // signal is received until selection is changed in Gecko.
+  bool mRetrieveSurroundingSignalReceived;
+  // mMaybeInDeadKeySequence is set to true when we detect a dead key press
+  // and set to false when we're sure dead key sequence has been finished.
+  // Note that we cannot detect which key event causes ending a dead key
+  // sequence.  For example, when you press dead key grave with ibus Spanish
+  // keyboard layout, it just consumes the key event when we call
+  // gtk_im_context_filter_keypress().  Then, pressing "Escape" key cancels
+  // the dead key sequence but we don't receive any signal and it's consumed
+  // by gtk_im_context_filter_keypress() normally.  On the other hand, when
+  // pressing "Shift" key causes exactly same behavior but dead key sequence
+  // isn't finished yet.
+  bool mMaybeInDeadKeySequence;
+  // mIsIMInAsyncKeyHandlingMode is set to true if we know that IM handles
+  // key events asynchronously.  I.e., filtered key event may come again
+  // later.
+  bool mIsIMInAsyncKeyHandlingMode;
+  // mIsKeySnooped is set to true if IM uses key snooper to listen key events.
+  // In such case, we won't receive key events if IME consumes the event.
+  bool mIsKeySnooped;
+  // mSetInputPurposeAndInputHints is set if `SetInputContext` wants `Focus`
+  // to set input-purpose and input-hints.
+  bool mSetInputPurposeAndInputHints;
+
+  // sLastFocusedContext is a pointer to the last focused instance of this
+  // class.  When a instance is destroyed and sLastFocusedContext refers it,
+  // this is cleared.  So, this refers valid pointer always.
+  static IMContextWrapper* sLastFocusedContext;
+
+  // sUseSimpleContext indeicates if password editors and editors with
+  // |ime-mode: disabled;| should use GtkIMContextSimple.
+  // If true, they use GtkIMContextSimple.  Otherwise, not.
+  static bool sUseSimpleContext;
+
+  // Callback methods for native IME events.  These methods should call
+  // the related instance methods simply.
+  static gboolean OnRetrieveSurroundingCallback(GtkIMContext* aContext,
+                                                IMContextWrapper* aModule);
+  static gboolean OnDeleteSurroundingCallback(GtkIMContext* aContext,
+                                              gint aOffset, gint aNChars,
+                                              IMContextWrapper* aModule);
+  static void OnCommitCompositionCallback(GtkIMContext* aContext,
+                                          const gchar* aString,
+                                          IMContextWrapper* aModule);
+  static void OnChangeCompositionCallback(GtkIMContext* aContext,
+                                          IMContextWrapper* aModule);
+  static void OnStartCompositionCallback(GtkIMContext* aContext,
+                                         IMContextWrapper* aModule);
+  static void OnEndCompositionCallback(GtkIMContext* aContext,
+                                       IMContextWrapper* aModule);
+
+  // The instance methods for the native IME events.
+  gboolean OnRetrieveSurroundingNative(GtkIMContext* aContext);
+  gboolean OnDeleteSurroundingNative(GtkIMContext* aContext, gint aOffset,
+                                     gint aNChars);
+  void OnCommitCompositionNative(GtkIMContext* aContext, const gchar* aString);
+  void OnChangeCompositionNative(GtkIMContext* aContext);
+  void OnStartCompositionNative(GtkIMContext* aContext);
+  void OnEndCompositionNative(GtkIMContext* aContext);
+
+  /**
+   * GetCurrentContext() returns current IM context which is chosen with the
+   * enabled state.
+   * WARNING:
+   *     When this class receives some signals for a composition after focus
+   *     is moved in Gecko, the result of this may be different from given
+   *     context by the signals.
+   */
+  GtkIMContext* GetCurrentContext() const;
+
+  /**
+   * GetActiveContext() returns a composing context or current context.
+   */
+  GtkIMContext* GetActiveContext() const {
+    return mComposingContext ? mComposingContext : GetCurrentContext();
+  }
+
+  // If the owner window and IM context have been destroyed, returns TRUE.
+  bool IsDestroyed() { return !mOwnerWindow; }
+
+  void NotifyIMEOfFocusChange(IMEFocusState aIMEFocusState);
+
+  // Initializes the instance.
+  void Init();
+
+  /**
+   * Reset the active context, i.e., if there is mComposingContext, reset it.
+   * Otherwise, reset current context.  Note that all native composition
+   * events during calling this will be ignored.
+   */
+  void ResetIME();
+
+  // Gets the current composition string by the native APIs.
+  void GetCompositionString(GtkIMContext* aContext,
+                            nsAString& aCompositionString);
+
+  /**
+   * Generates our text range array from current composition string.
+   *
+   * @param aContext              A GtkIMContext which is being handled.
+   * @param aCompositionString    The data to be dispatched with
+   *                              compositionchange event.
+   */
+  already_AddRefed<TextRangeArray> CreateTextRangeArray(
+      GtkIMContext* aContext, const nsAString& aCompositionString);
+
+  /**
+   * SetTextRange() initializes aTextRange with aPangoAttrIter.
+   *
+   * @param aPangoAttrIter            An iter which represents a clause of the
+   *                                  composition string.
+   * @param aUTF8CompositionString    The whole composition string (UTF-8).
+   * @param aUTF16CaretOffset         The caret offset in the composition
+   *                                  string encoded as UTF-16.
+   * @param aTextRange                The result.
+   * @return                          true if this initializes aTextRange.
+   *                                  Otherwise, false.
+   */
+  bool SetTextRange(PangoAttrIterator* aPangoAttrIter,
+                    const gchar* aUTF8CompositionString,
+                    uint32_t aUTF16CaretOffset, TextRange& aTextRange) const;
+
+  /**
+   * ToNscolor() converts the PangoColor in aPangoAttrColor to nscolor.
+   */
+  static nscolor ToNscolor(PangoAttrColor* aPangoAttrColor);
+
+  /**
+   * Move the candidate window with "fake" cursor position.
+   *
+   * @param aContext              A GtkIMContext which is being handled.
+   */
+  void SetCursorPosition(GtkIMContext* aContext);
+
+  // Queries the current selection offset of the window.
+  uint32_t GetSelectionOffset(nsWindow* aWindow);
+
+  // Get current paragraph text content and cursor position
+  nsresult GetCurrentParagraph(nsAString& aText, uint32_t& aCursorPos);
+
+  /**
+   * Delete text portion
+   *
+   * @param aContext              A GtkIMContext which is being handled.
+   * @param aOffset               Start offset of the range to delete.
+   * @param aNChars               Count of characters to delete.  It depends
+   *                              on |g_utf8_strlen()| what is one character.
+   */
+  nsresult DeleteText(GtkIMContext* aContext, int32_t aOffset,
+                      uint32_t aNChars);
+
+  // Called before destroying the context to work around some platform bugs.
+  void PrepareToDestroyContext(GtkIMContext* aContext);
+
+  /**
+   *  WARNING:
+   *    Following methods dispatch gecko events.  Then, the focused widget
+   *    can be destroyed, and also it can be stolen focus.  If they returns
+   *    FALSE, callers cannot continue the composition.
+   *      - MaybeDispatchKeyEventAsProcessedByIME
+   *      - DispatchCompositionStart
+   *      - DispatchCompositionChangeEvent
+   *      - DispatchCompositionCommitEvent
+   */
+
+  /**
+   * Dispatch an eKeyDown or eKeyUp event whose mKeyCode value is
+   * NS_VK_PROCESSKEY and mKeyNameIndex is KEY_NAME_INDEX_Process if
+   * we're not in a dead key sequence, mProcessingKeyEvent is nullptr
+   * but mPostingKeyEvents is not empty or mProcessingKeyEvent is not
+   * nullptr and mKeyboardEventWasDispatched is still false.  If this
+   * dispatches a keyboard event, this sets mKeyboardEventWasDispatched
+   * to true.
+   *
+   * @param aFollowingEvent       The following event message.
+   * @return                      If the caller can continue to handle
+   *                              composition, returns true.  Otherwise,
+   *                              false.  For example, if focus is moved
+   *                              by dispatched keyboard event, returns
+   *                              false.
+   */
+  bool MaybeDispatchKeyEventAsProcessedByIME(EventMessage aFollowingEvent);
+
+  /**
+   * Dispatches a composition start event.
+   *
+   * @param aContext              A GtkIMContext which is being handled.
+   * @return                      true if the focused widget is neither
+   *                              destroyed nor changed.  Otherwise, false.
+   */
+  bool DispatchCompositionStart(GtkIMContext* aContext);
+
+  /**
+   * Dispatches a compositionchange event.
+   *
+   * @param aContext              A GtkIMContext which is being handled.
+   * @param aCompositionString    New composition string.
+   * @return                      true if the focused widget is neither
+   *                              destroyed nor changed.  Otherwise, false.
+   */
+  bool DispatchCompositionChangeEvent(GtkIMContext* aContext,
+                                      const nsAString& aCompositionString);
+
+  /**
+   * Dispatches a compositioncommit event or compositioncommitasis event.
+   *
+   * @param aContext              A GtkIMContext which is being handled.
+   * @param aCommitString         If this is nullptr, the composition will
+   *                              be committed with last dispatched data.
+   *                              Otherwise, the composition will be
+   *                              committed with this value.
+   * @return                      true if the focused widget is neither
+   *                              destroyed nor changed.  Otherwise, false.
+   */
+  bool DispatchCompositionCommitEvent(GtkIMContext* aContext,
+                                      const nsAString* aCommitString = nullptr);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // #ifndef IMContextWrapper_h_
diff --git a/widget/gtk/InProcessGtkCompositorWidget.cpp b/widget/gtk/InProcessGtkCompositorWidget.cpp
new file mode 100644
index 0000000000..bffd6f5a7f
--- /dev/null
+++ b/widget/gtk/InProcessGtkCompositorWidget.cpp
@@ -0,0 +1,44 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HeadlessCompositorWidget.h"
+#include "HeadlessWidget.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+
+#include "InProcessGtkCompositorWidget.h"
+#include "VsyncDispatcher.h"
+#include "nsWindow.h"
+
+namespace mozilla::widget {
+
+/* static */
+RefPtr<CompositorWidget> CompositorWidget::CreateLocal(
+    const CompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions, nsIWidget* aWidget) {
+  if (aInitData.type() ==
+      CompositorWidgetInitData::THeadlessCompositorWidgetInitData) {
+    return new HeadlessCompositorWidget(
+        aInitData.get_HeadlessCompositorWidgetInitData(), aOptions,
+        static_cast<HeadlessWidget*>(aWidget));
+  } else {
+    return new InProcessGtkCompositorWidget(
+        aInitData.get_GtkCompositorWidgetInitData(), aOptions,
+        static_cast<nsWindow*>(aWidget));
+  }
+}
+
+InProcessGtkCompositorWidget::InProcessGtkCompositorWidget(
+    const GtkCompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions, nsWindow* aWindow)
+    : GtkCompositorWidget(aInitData, aOptions, aWindow) {}
+
+void InProcessGtkCompositorWidget::ObserveVsync(VsyncObserver* aObserver) {
+  if (RefPtr<CompositorVsyncDispatcher> cvd =
+          mWidget->GetCompositorVsyncDispatcher()) {
+    cvd->SetCompositorVsyncObserver(aObserver);
+  }
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/InProcessGtkCompositorWidget.h b/widget/gtk/InProcessGtkCompositorWidget.h
new file mode 100644
index 0000000000..bd7e68d6fb
--- /dev/null
+++ b/widget/gtk/InProcessGtkCompositorWidget.h
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_gtk_InProcessGtkCompositorWidget_h
+#define widget_gtk_InProcessGtkCompositorWidget_h
+
+#include "GtkCompositorWidget.h"
+
+class nsWindow;
+
+namespace mozilla {
+namespace widget {
+
+class InProcessGtkCompositorWidget final : public GtkCompositorWidget {
+ public:
+  InProcessGtkCompositorWidget(const GtkCompositorWidgetInitData& aInitData,
+                               const layers::CompositorOptions& aOptions,
+                               nsWindow* aWindow);
+
+  // CompositorWidgetDelegate
+
+  void ObserveVsync(VsyncObserver* aObserver) override;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_gtk_InProcessGtkCompositorWidget_h
diff --git a/widget/gtk/MPRISInterfaceDescription.h b/widget/gtk/MPRISInterfaceDescription.h
new file mode 100644
index 0000000000..28e719e651
--- /dev/null
+++ b/widget/gtk/MPRISInterfaceDescription.h
@@ -0,0 +1,91 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_GTK_MPRIS_INTERFACE_DESCRIPTION_H_
+#define WIDGET_GTK_MPRIS_INTERFACE_DESCRIPTION_H_
+
+#include <gio/gio.h>
+
+extern const gchar introspection_xml[] =
+    // adopted from https://github.com/freedesktop/mpris-spec/blob/master/spec/org.mpris.MediaPlayer2.xml
+    // everything starting with tp can be removed, as it is used for HTML Spec Documentation Generation
+    "<node>"
+        "<interface name=\"org.mpris.MediaPlayer2\">"
+            "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "<method name=\"Raise\"/>"
+            "<method name=\"Quit\"/>"
+            "<property name=\"CanQuit\" type=\"b\" access=\"read\"/>"
+            "<property name=\"CanRaise\" type=\"b\" access=\"read\"/>"
+            "<property name=\"HasTrackList\" type=\"b\" access=\"read\"/>"
+            "<property name=\"Identity\" type=\"s\" access=\"read\"/>"
+            "<property name=\"DesktopEntry\" type=\"s\" access=\"read\"/>"
+            "<property name=\"SupportedUriSchemes\" type=\"as\" access=\"read\"/>"
+            "<property name=\"SupportedMimeTypes\" type=\"as\" access=\"read\"/>"
+        "</interface>"
+            // Note that every property emits a changed signal (which is default) apart from Position.
+        "<interface name=\"org.mpris.MediaPlayer2.Player\">"
+            "<method name=\"Next\"/>"
+            "<method name=\"Previous\"/>"
+            "<method name=\"Pause\"/>"
+            "<method name=\"PlayPause\"/>"
+            "<method name=\"Stop\"/>"
+            "<method name=\"Play\"/>"
+            "<method name=\"Seek\">"
+                "<arg direction=\"in\" type=\"x\" name=\"Offset\"/>"
+            "</method>"
+            "<method name=\"SetPosition\">"
+                "<arg direction=\"in\" type=\"o\" name=\"TrackId\"/>"
+                "<arg direction=\"in\" type=\"x\" name=\"Position\"/>"
+            "</method>"
+            "<method name=\"OpenUri\">"
+                "<arg direction=\"in\" type=\"s\" name=\"Uri\"/>"
+            "</method>"
+            "<property name=\"PlaybackStatus\" type=\"s\" access=\"read\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "</property>"
+            "<property name=\"Rate\" type=\"d\" access=\"readwrite\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "</property>"
+            "<property name=\"Metadata\" type=\"a{sv}\" access=\"read\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "</property>"
+            "<property name=\"Volume\" type=\"d\" access=\"readwrite\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "</property>"
+            "<property name=\"Position\" type=\"x\" access=\"read\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"false\"/>"
+            "</property>"
+            "<property name=\"MinimumRate\" type=\"d\" access=\"read\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "</property>"
+            "<property name=\"MaximumRate\" type=\"d\" access=\"read\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "</property>"
+            "<property name=\"CanGoNext\" type=\"b\" access=\"read\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "</property>"
+            "<property name=\"CanGoPrevious\" type=\"b\" access=\"read\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "</property>"
+            "<property name=\"CanPlay\" type=\"b\" access=\"read\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "</property>"
+            "<property name=\"CanPause\" type=\"b\" access=\"read\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "</property>"
+            "<property name=\"CanSeek\" type=\"b\" access=\"read\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"true\"/>"
+            "</property>"
+            "<property name=\"CanControl\" type=\"b\" access=\"read\">"
+                "<annotation name=\"org.freedesktop.DBus.Property.EmitsChangedSignal\" value=\"false\"/>"
+            "</property>"
+            "<signal name=\"Seeked\">"
+                "<arg name=\"Position\" type=\"x\"/>"
+            "</signal>"
+        "</interface>"
+    "</node>";
+
+#endif  // WIDGET_GTK_MPRIS_INTERFACE_DESCRIPTION_H_
diff --git a/widget/gtk/MPRISServiceHandler.cpp b/widget/gtk/MPRISServiceHandler.cpp
new file mode 100644
index 0000000000..ae1ef8654d
--- /dev/null
+++ b/widget/gtk/MPRISServiceHandler.cpp
@@ -0,0 +1,909 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MPRISServiceHandler.h"
+
+#include <stdint.h>
+#include <inttypes.h>
+#include <unordered_map>
+
+#include "MPRISInterfaceDescription.h"
+#include "mozilla/dom/MediaControlUtils.h"
+#include "mozilla/GRefPtr.h"
+#include "mozilla/GUniquePtr.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/Sprintf.h"
+#include "nsXULAppAPI.h"
+#include "nsIXULAppInfo.h"
+#include "nsIOutputStream.h"
+#include "nsNetUtil.h"
+#include "nsServiceManagerUtils.h"
+#include "WidgetUtilsGtk.h"
+#include "AsyncDBus.h"
+#include "prio.h"
+
+#define LOGMPRIS(msg, ...)                   \
+  MOZ_LOG(gMediaControlLog, LogLevel::Debug, \
+          ("MPRISServiceHandler=%p, " msg, this, ##__VA_ARGS__))
+
+namespace mozilla {
+namespace widget {
+
+// A global counter tracking the total images saved in the system and it will be
+// used to form a unique image file name.
+static uint32_t gImageNumber = 0;
+
+static inline Maybe<dom::MediaControlKey> GetMediaControlKey(
+    const gchar* aMethodName) {
+  const std::unordered_map<std::string, dom::MediaControlKey> map = {
+      {"Raise", dom::MediaControlKey::Focus},
+      {"Next", dom::MediaControlKey::Nexttrack},
+      {"Previous", dom::MediaControlKey::Previoustrack},
+      {"Pause", dom::MediaControlKey::Pause},
+      {"PlayPause", dom::MediaControlKey::Playpause},
+      {"Stop", dom::MediaControlKey::Stop},
+      {"Play", dom::MediaControlKey::Play}};
+
+  auto it = map.find(aMethodName);
+  return it == map.end() ? Nothing() : Some(it->second);
+}
+
+static void HandleMethodCall(GDBusConnection* aConnection, const gchar* aSender,
+                             const gchar* aObjectPath,
+                             const gchar* aInterfaceName,
+                             const gchar* aMethodName, GVariant* aParameters,
+                             GDBusMethodInvocation* aInvocation,
+                             gpointer aUserData) {
+  MOZ_ASSERT(aUserData);
+  MOZ_ASSERT(NS_IsMainThread());
+
+  Maybe<dom::MediaControlKey> key = GetMediaControlKey(aMethodName);
+  if (key.isNothing()) {
+    g_dbus_method_invocation_return_error(
+        aInvocation, G_DBUS_ERROR, G_DBUS_ERROR_NOT_SUPPORTED,
+        "Method %s.%s.%s not supported", aObjectPath, aInterfaceName,
+        aMethodName);
+    return;
+  }
+
+  MPRISServiceHandler* handler = static_cast<MPRISServiceHandler*>(aUserData);
+  if (handler->PressKey(key.value())) {
+    g_dbus_method_invocation_return_value(aInvocation, nullptr);
+  } else {
+    g_dbus_method_invocation_return_error(
+        aInvocation, G_DBUS_ERROR, G_DBUS_ERROR_FAILED,
+        "%s.%s.%s is not available now", aObjectPath, aInterfaceName,
+        aMethodName);
+  }
+}
+
+enum class Property : uint8_t {
+  eIdentity,
+  eDesktopEntry,
+  eHasTrackList,
+  eCanRaise,
+  eCanQuit,
+  eSupportedUriSchemes,
+  eSupportedMimeTypes,
+  eCanGoNext,
+  eCanGoPrevious,
+  eCanPlay,
+  eCanPause,
+  eCanSeek,
+  eCanControl,
+  eGetPlaybackStatus,
+  eGetMetadata,
+};
+
+static inline Maybe<dom::MediaControlKey> GetPairedKey(Property aProperty) {
+  switch (aProperty) {
+    case Property::eCanRaise:
+      return Some(dom::MediaControlKey::Focus);
+    case Property::eCanGoNext:
+      return Some(dom::MediaControlKey::Nexttrack);
+    case Property::eCanGoPrevious:
+      return Some(dom::MediaControlKey::Previoustrack);
+    case Property::eCanPlay:
+      return Some(dom::MediaControlKey::Play);
+    case Property::eCanPause:
+      return Some(dom::MediaControlKey::Pause);
+    default:
+      return Nothing();
+  }
+}
+
+static inline Maybe<Property> GetProperty(const gchar* aPropertyName) {
+  const std::unordered_map<std::string, Property> map = {
+      // org.mpris.MediaPlayer2 properties
+      {"Identity", Property::eIdentity},
+      {"DesktopEntry", Property::eDesktopEntry},
+      {"HasTrackList", Property::eHasTrackList},
+      {"CanRaise", Property::eCanRaise},
+      {"CanQuit", Property::eCanQuit},
+      {"SupportedUriSchemes", Property::eSupportedUriSchemes},
+      {"SupportedMimeTypes", Property::eSupportedMimeTypes},
+      // org.mpris.MediaPlayer2.Player properties
+      {"CanGoNext", Property::eCanGoNext},
+      {"CanGoPrevious", Property::eCanGoPrevious},
+      {"CanPlay", Property::eCanPlay},
+      {"CanPause", Property::eCanPause},
+      {"CanSeek", Property::eCanSeek},
+      {"CanControl", Property::eCanControl},
+      {"PlaybackStatus", Property::eGetPlaybackStatus},
+      {"Metadata", Property::eGetMetadata}};
+
+  auto it = map.find(aPropertyName);
+  return (it == map.end() ? Nothing() : Some(it->second));
+}
+
+static GVariant* HandleGetProperty(GDBusConnection* aConnection,
+                                   const gchar* aSender,
+                                   const gchar* aObjectPath,
+                                   const gchar* aInterfaceName,
+                                   const gchar* aPropertyName, GError** aError,
+                                   gpointer aUserData) {
+  MOZ_ASSERT(aUserData);
+  MOZ_ASSERT(NS_IsMainThread());
+
+  Maybe<Property> property = GetProperty(aPropertyName);
+  if (property.isNothing()) {
+    g_set_error(aError, G_DBUS_ERROR, G_DBUS_ERROR_NOT_SUPPORTED,
+                "%s.%s %s is not supported", aObjectPath, aInterfaceName,
+                aPropertyName);
+    return nullptr;
+  }
+
+  MPRISServiceHandler* handler = static_cast<MPRISServiceHandler*>(aUserData);
+  switch (property.value()) {
+    case Property::eSupportedUriSchemes:
+    case Property::eSupportedMimeTypes:
+      // No plan to implement OpenUri for now
+      return g_variant_new_strv(nullptr, 0);
+    case Property::eGetPlaybackStatus:
+      return handler->GetPlaybackStatus();
+    case Property::eGetMetadata:
+      return handler->GetMetadataAsGVariant();
+    case Property::eIdentity:
+      return g_variant_new_string(handler->Identity());
+    case Property::eDesktopEntry:
+      return g_variant_new_string(handler->DesktopEntry());
+    case Property::eHasTrackList:
+    case Property::eCanQuit:
+    case Property::eCanSeek:
+      return g_variant_new_boolean(false);
+    // Play/Pause would be blocked if CanControl is false
+    case Property::eCanControl:
+      return g_variant_new_boolean(true);
+    case Property::eCanRaise:
+    case Property::eCanGoNext:
+    case Property::eCanGoPrevious:
+    case Property::eCanPlay:
+    case Property::eCanPause:
+      Maybe<dom::MediaControlKey> key = GetPairedKey(property.value());
+      MOZ_ASSERT(key.isSome());
+      return g_variant_new_boolean(handler->IsMediaKeySupported(key.value()));
+  }
+
+  MOZ_ASSERT_UNREACHABLE("Switch statement is incomplete");
+  return nullptr;
+}
+
+static gboolean HandleSetProperty(GDBusConnection* aConnection,
+                                  const gchar* aSender,
+                                  const gchar* aObjectPath,
+                                  const gchar* aInterfaceName,
+                                  const gchar* aPropertyName, GVariant* aValue,
+                                  GError** aError, gpointer aUserData) {
+  MOZ_ASSERT(aUserData);
+  MOZ_ASSERT(NS_IsMainThread());
+  g_set_error(aError, G_IO_ERROR, G_IO_ERROR_FAILED,
+              "%s:%s setting is not supported", aInterfaceName, aPropertyName);
+  return false;
+}
+
+static const GDBusInterfaceVTable gInterfaceVTable = {
+    HandleMethodCall, HandleGetProperty, HandleSetProperty};
+
+void MPRISServiceHandler::OnNameAcquiredStatic(GDBusConnection* aConnection,
+                                               const gchar* aName,
+                                               gpointer aUserData) {
+  MOZ_ASSERT(aUserData);
+  static_cast<MPRISServiceHandler*>(aUserData)->OnNameAcquired(aConnection,
+                                                               aName);
+}
+
+void MPRISServiceHandler::OnNameLostStatic(GDBusConnection* aConnection,
+                                           const gchar* aName,
+                                           gpointer aUserData) {
+  MOZ_ASSERT(aUserData);
+  static_cast<MPRISServiceHandler*>(aUserData)->OnNameLost(aConnection, aName);
+}
+
+void MPRISServiceHandler::OnBusAcquiredStatic(GDBusConnection* aConnection,
+                                              const gchar* aName,
+                                              gpointer aUserData) {
+  MOZ_ASSERT(aUserData);
+  static_cast<MPRISServiceHandler*>(aUserData)->OnBusAcquired(aConnection,
+                                                              aName);
+}
+
+void MPRISServiceHandler::OnNameAcquired(GDBusConnection* aConnection,
+                                         const gchar* aName) {
+  LOGMPRIS("OnNameAcquired: %s", aName);
+  mConnection = aConnection;
+}
+
+void MPRISServiceHandler::OnNameLost(GDBusConnection* aConnection,
+                                     const gchar* aName) {
+  LOGMPRIS("OnNameLost: %s", aName);
+  mConnection = nullptr;
+  if (!mRootRegistrationId) {
+    return;
+  }
+
+  if (!aConnection) {
+    return;
+  }
+
+  if (g_dbus_connection_unregister_object(aConnection, mRootRegistrationId)) {
+    mRootRegistrationId = 0;
+  } else {
+    // Note: Most code examples in the internet probably dont't even check the
+    // result here, but
+    // according to the spec it _can_ return false.
+    LOGMPRIS("Unable to unregister root object from within onNameLost!");
+  }
+
+  if (!mPlayerRegistrationId) {
+    return;
+  }
+
+  if (g_dbus_connection_unregister_object(aConnection, mPlayerRegistrationId)) {
+    mPlayerRegistrationId = 0;
+  } else {
+    // Note: Most code examples in the internet probably dont't even check the
+    // result here, but
+    // according to the spec it _can_ return false.
+    LOGMPRIS("Unable to unregister object from within onNameLost!");
+  }
+}
+
+void MPRISServiceHandler::OnBusAcquired(GDBusConnection* aConnection,
+                                        const gchar* aName) {
+  GUniquePtr<GError> error;
+  LOGMPRIS("OnBusAcquired: %s", aName);
+
+  mRootRegistrationId = g_dbus_connection_register_object(
+      aConnection, DBUS_MPRIS_OBJECT_PATH, mIntrospectionData->interfaces[0],
+      &gInterfaceVTable, this,  /* user_data */
+      nullptr,                  /* user_data_free_func */
+      getter_Transfers(error)); /* GError** */
+
+  if (mRootRegistrationId == 0) {
+    LOGMPRIS("Failed at root registration: %s",
+             error ? error->message : "Unknown Error");
+    return;
+  }
+
+  mPlayerRegistrationId = g_dbus_connection_register_object(
+      aConnection, DBUS_MPRIS_OBJECT_PATH, mIntrospectionData->interfaces[1],
+      &gInterfaceVTable, this,  /* user_data */
+      nullptr,                  /* user_data_free_func */
+      getter_Transfers(error)); /* GError** */
+
+  if (mPlayerRegistrationId == 0) {
+    LOGMPRIS("Failed at object registration: %s",
+             error ? error->message : "Unknown Error");
+  }
+}
+
+void MPRISServiceHandler::SetServiceName(const char* aName) {
+  nsCString dbusName(aName);
+  dbusName.ReplaceChar(':', '_');
+  dbusName.ReplaceChar('.', '_');
+  mServiceName =
+      nsCString(DBUS_MPRIS_SERVICE_NAME) + nsCString(".instance") + dbusName;
+}
+
+const char* MPRISServiceHandler::GetServiceName() { return mServiceName.get(); }
+
+/* static */
+void g_bus_get_callback(GObject* aSourceObject, GAsyncResult* aRes,
+                        gpointer aUserData) {
+  GUniquePtr<GError> error;
+
+  GDBusConnection* conn = g_bus_get_finish(aRes, getter_Transfers(error));
+  if (!conn) {
+    if (!IsCancelledGError(error.get())) {
+      NS_WARNING(nsPrintfCString("Failure at g_bus_get_finish: %s",
+                                 error ? error->message : "Unknown Error")
+                     .get());
+    }
+    return;
+  }
+
+  MPRISServiceHandler* handler = static_cast<MPRISServiceHandler*>(aUserData);
+  if (!handler) {
+    NS_WARNING(
+        nsPrintfCString("Failure to get a MPRISServiceHandler*: %p", handler)
+            .get());
+    return;
+  }
+
+  handler->OwnName(conn);
+}
+
+void MPRISServiceHandler::OwnName(GDBusConnection* aConnection) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  SetServiceName(g_dbus_connection_get_unique_name(aConnection));
+
+  GUniquePtr<GError> error;
+
+  InitIdentity();
+  mOwnerId = g_bus_own_name_on_connection(
+      aConnection, GetServiceName(),
+      // Enter a waiting queue until this service name is free
+      // (likely another FF instance is running/has been crashed)
+      G_BUS_NAME_OWNER_FLAGS_NONE, OnNameAcquiredStatic, OnNameLostStatic, this,
+      nullptr);
+
+  /* parse introspection data */
+  mIntrospectionData = dont_AddRef(
+      g_dbus_node_info_new_for_xml(introspection_xml, getter_Transfers(error)));
+
+  if (!mIntrospectionData) {
+    LOGMPRIS("Failed at parsing XML Interface definition: %s",
+             error ? error->message : "Unknown Error");
+    return;
+  }
+
+  OnBusAcquired(aConnection, GetServiceName());
+}
+
+bool MPRISServiceHandler::Open() {
+  MOZ_ASSERT(!mInitialized);
+  MOZ_ASSERT(NS_IsMainThread());
+
+  mDBusGetCancellable = dont_AddRef(g_cancellable_new());
+  g_bus_get(G_BUS_TYPE_SESSION, mDBusGetCancellable, g_bus_get_callback, this);
+
+  mInitialized = true;
+  return true;
+}
+
+MPRISServiceHandler::MPRISServiceHandler() = default;
+MPRISServiceHandler::~MPRISServiceHandler() {
+  MOZ_ASSERT(!mInitialized, "Close hasn't been called!");
+}
+
+void MPRISServiceHandler::Close() {
+  // Reset playback state and metadata before disconnect from dbus.
+  SetPlaybackState(dom::MediaSessionPlaybackState::None);
+  ClearMetadata();
+
+  OnNameLost(mConnection, GetServiceName());
+
+  if (mDBusGetCancellable) {
+    g_cancellable_cancel(mDBusGetCancellable);
+    mDBusGetCancellable = nullptr;
+  }
+
+  if (mOwnerId != 0) {
+    g_bus_unown_name(mOwnerId);
+  }
+
+  mIntrospectionData = nullptr;
+
+  mInitialized = false;
+  MediaControlKeySource::Close();
+}
+
+bool MPRISServiceHandler::IsOpened() const { return mInitialized; }
+
+void MPRISServiceHandler::InitIdentity() {
+  nsresult rv;
+  nsCOMPtr<nsIXULAppInfo> appInfo =
+      do_GetService("@mozilla.org/xre/app-info;1", &rv);
+
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  rv = appInfo->GetVendor(mIdentity);
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  rv = appInfo->GetName(mDesktopEntry);
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+
+  mIdentity.Append(' ');
+  mIdentity.Append(mDesktopEntry);
+
+  // Compute the desktop entry name like nsAppRunner does for g_set_prgname
+  ToLowerCase(mDesktopEntry);
+}
+
+const char* MPRISServiceHandler::Identity() const {
+  NS_WARNING_ASSERTION(mInitialized,
+                       "MPRISServiceHandler should have been initialized.");
+  return mIdentity.get();
+}
+
+const char* MPRISServiceHandler::DesktopEntry() const {
+  NS_WARNING_ASSERTION(mInitialized,
+                       "MPRISServiceHandler should have been initialized.");
+  return mDesktopEntry.get();
+}
+
+bool MPRISServiceHandler::PressKey(dom::MediaControlKey aKey) const {
+  MOZ_ASSERT(mInitialized);
+  if (!IsMediaKeySupported(aKey)) {
+    LOGMPRIS("%s is not supported", ToMediaControlKeyStr(aKey));
+    return false;
+  }
+  LOGMPRIS("Press %s", ToMediaControlKeyStr(aKey));
+  EmitEvent(aKey);
+  return true;
+}
+
+void MPRISServiceHandler::SetPlaybackState(
+    dom::MediaSessionPlaybackState aState) {
+  LOGMPRIS("SetPlaybackState");
+  if (mPlaybackState == aState) {
+    return;
+  }
+
+  MediaControlKeySource::SetPlaybackState(aState);
+
+  GVariant* state = GetPlaybackStatus();
+  GVariantBuilder builder;
+  g_variant_builder_init(&builder, G_VARIANT_TYPE("a{sv}"));
+  g_variant_builder_add(&builder, "{sv}", "PlaybackStatus", state);
+
+  GVariant* parameters = g_variant_new(
+      "(sa{sv}as)", DBUS_MPRIS_PLAYER_INTERFACE, &builder, nullptr);
+
+  LOGMPRIS("Emitting MPRIS property changes for 'PlaybackStatus'");
+  Unused << EmitPropertiesChangedSignal(parameters);
+}
+
+GVariant* MPRISServiceHandler::GetPlaybackStatus() const {
+  switch (GetPlaybackState()) {
+    case dom::MediaSessionPlaybackState::Playing:
+      return g_variant_new_string("Playing");
+    case dom::MediaSessionPlaybackState::Paused:
+      return g_variant_new_string("Paused");
+    case dom::MediaSessionPlaybackState::None:
+      return g_variant_new_string("Stopped");
+    default:
+      MOZ_ASSERT_UNREACHABLE("Invalid Playback State");
+      return nullptr;
+  }
+}
+
+void MPRISServiceHandler::SetMediaMetadata(
+    const dom::MediaMetadataBase& aMetadata) {
+  // Reset the index of the next available image to be fetched in the artwork,
+  // before checking the fetching process should be started or not. The image
+  // fetching process could be skipped if the image being fetching currently is
+  // in the artwork. If the current image fetching fails, the next availabe
+  // candidate should be the first image in the latest artwork
+  mNextImageIndex = 0;
+
+  // No need to fetch a MPRIS image if
+  // 1) MPRIS image is being fetched, and the one in fetching is in the artwork
+  // 2) MPRIS image is not being fetched, and the one in use is in the artwork
+  if (!mFetchingUrl.IsEmpty()) {
+    if (dom::IsImageIn(aMetadata.mArtwork, mFetchingUrl)) {
+      LOGMPRIS(
+          "No need to load MPRIS image. The one being processed is in the "
+          "artwork");
+      // Set MPRIS without the image first. The image will be loaded to MPRIS
+      // asynchronously once it's fetched and saved into a local file
+      SetMediaMetadataInternal(aMetadata);
+      return;
+    }
+  } else if (!mCurrentImageUrl.IsEmpty()) {
+    if (dom::IsImageIn(aMetadata.mArtwork, mCurrentImageUrl)) {
+      LOGMPRIS("No need to load MPRIS image. The one in use is in the artwork");
+      SetMediaMetadataInternal(aMetadata, false);
+      return;
+    }
+  }
+
+  // Set MPRIS without the image first then load the image to MPRIS
+  // asynchronously
+  SetMediaMetadataInternal(aMetadata);
+  LoadImageAtIndex(mNextImageIndex++);
+}
+
+bool MPRISServiceHandler::EmitMetadataChanged() const {
+  GVariantBuilder builder;
+  g_variant_builder_init(&builder, G_VARIANT_TYPE("a{sv}"));
+  g_variant_builder_add(&builder, "{sv}", "Metadata", GetMetadataAsGVariant());
+
+  GVariant* parameters = g_variant_new(
+      "(sa{sv}as)", DBUS_MPRIS_PLAYER_INTERFACE, &builder, nullptr);
+
+  LOGMPRIS("Emit MPRIS property changes for 'Metadata'");
+  return EmitPropertiesChangedSignal(parameters);
+}
+
+void MPRISServiceHandler::SetMediaMetadataInternal(
+    const dom::MediaMetadataBase& aMetadata, bool aClearArtUrl) {
+  mMPRISMetadata.UpdateFromMetadataBase(aMetadata);
+  if (aClearArtUrl) {
+    mMPRISMetadata.mArtUrl.Truncate();
+  }
+  EmitMetadataChanged();
+}
+
+void MPRISServiceHandler::ClearMetadata() {
+  mMPRISMetadata.Clear();
+  mImageFetchRequest.DisconnectIfExists();
+  RemoveAllLocalImages();
+  mCurrentImageUrl.Truncate();
+  mFetchingUrl.Truncate();
+  mNextImageIndex = 0;
+  mSupportedKeys = 0;
+  EmitMetadataChanged();
+}
+
+void MPRISServiceHandler::LoadImageAtIndex(const size_t aIndex) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (aIndex >= mMPRISMetadata.mArtwork.Length()) {
+    LOGMPRIS("Stop loading image to MPRIS. No available image");
+    mImageFetchRequest.DisconnectIfExists();
+    return;
+  }
+
+  const dom::MediaImage& image = mMPRISMetadata.mArtwork[aIndex];
+
+  if (!dom::IsValidImageUrl(image.mSrc)) {
+    LOGMPRIS("Skip the image with invalid URL. Try next image");
+    LoadImageAtIndex(mNextImageIndex++);
+    return;
+  }
+
+  mImageFetchRequest.DisconnectIfExists();
+  mFetchingUrl = image.mSrc;
+
+  mImageFetcher = MakeUnique<dom::FetchImageHelper>(image);
+  RefPtr<MPRISServiceHandler> self = this;
+  mImageFetcher->FetchImage()
+      ->Then(
+          AbstractThread::MainThread(), __func__,
+          [this, self](const nsCOMPtr<imgIContainer>& aImage) {
+            LOGMPRIS("The image is fetched successfully");
+            mImageFetchRequest.Complete();
+
+            uint32_t size = 0;
+            char* data = nullptr;
+            // Only used to hold the image data
+            nsCOMPtr<nsIInputStream> inputStream;
+            nsresult rv = dom::GetEncodedImageBuffer(
+                aImage, mMimeType, getter_AddRefs(inputStream), &size, &data);
+            if (NS_FAILED(rv) || !inputStream || size == 0 || !data) {
+              LOGMPRIS("Failed to get the image buffer info. Try next image");
+              LoadImageAtIndex(mNextImageIndex++);
+              return;
+            }
+
+            if (SetImageToDisplay(data, size)) {
+              mCurrentImageUrl = mFetchingUrl;
+              LOGMPRIS("The MPRIS image is updated to the image from: %s",
+                       NS_ConvertUTF16toUTF8(mCurrentImageUrl).get());
+            } else {
+              LOGMPRIS("Failed to set image to MPRIS");
+              mCurrentImageUrl.Truncate();
+            }
+
+            mFetchingUrl.Truncate();
+          },
+          [this, self](bool) {
+            LOGMPRIS("Failed to fetch image. Try next image");
+            mImageFetchRequest.Complete();
+            mFetchingUrl.Truncate();
+            LoadImageAtIndex(mNextImageIndex++);
+          })
+      ->Track(mImageFetchRequest);
+}
+
+bool MPRISServiceHandler::SetImageToDisplay(const char* aImageData,
+                                            uint32_t aDataSize) {
+  if (!RenewLocalImageFile(aImageData, aDataSize)) {
+    return false;
+  }
+  MOZ_ASSERT(mLocalImageFile);
+
+  mMPRISMetadata.mArtUrl = nsCString("file://");
+  mMPRISMetadata.mArtUrl.Append(mLocalImageFile->NativePath());
+
+  LOGMPRIS("The image file is created at %s", mMPRISMetadata.mArtUrl.get());
+  return EmitMetadataChanged();
+}
+
+bool MPRISServiceHandler::RenewLocalImageFile(const char* aImageData,
+                                              uint32_t aDataSize) {
+  MOZ_ASSERT(aImageData);
+  MOZ_ASSERT(aDataSize != 0);
+
+  if (!InitLocalImageFile()) {
+    LOGMPRIS("Failed to create a new image");
+    return false;
+  }
+
+  MOZ_ASSERT(mLocalImageFile);
+  nsCOMPtr<nsIOutputStream> out;
+  NS_NewLocalFileOutputStream(getter_AddRefs(out), mLocalImageFile,
+                              PR_RDWR | PR_CREATE_FILE | PR_TRUNCATE);
+  uint32_t written;
+  nsresult rv = out->Write(aImageData, aDataSize, &written);
+  if (NS_FAILED(rv) || written != aDataSize) {
+    LOGMPRIS("Failed to write an image file");
+    RemoveAllLocalImages();
+    return false;
+  }
+
+  return true;
+}
+
+static const char* GetImageFileExtension(const char* aMimeType) {
+  MOZ_ASSERT(strcmp(aMimeType, IMAGE_PNG) == 0);
+  return "png";
+}
+
+bool MPRISServiceHandler::InitLocalImageFile() {
+  RemoveAllLocalImages();
+
+  if (!InitLocalImageFolder()) {
+    return false;
+  }
+
+  MOZ_ASSERT(mLocalImageFolder);
+  MOZ_ASSERT(!mLocalImageFile);
+  nsresult rv = mLocalImageFolder->Clone(getter_AddRefs(mLocalImageFile));
+  if (NS_FAILED(rv)) {
+    LOGMPRIS("Failed to get the image folder");
+    return false;
+  }
+
+  auto cleanup =
+      MakeScopeExit([this, self = RefPtr<MPRISServiceHandler>(this)] {
+        mLocalImageFile = nullptr;
+      });
+
+  // Create an unique file name to work around the file caching mechanism in the
+  // Ubuntu. Once the image X specified by the filename Y is used in Ubuntu's
+  // MPRIS, this pair will be cached. As long as the filename is same, even the
+  // file content specified by Y is changed to Z, the image will stay unchanged.
+  // The image shown in the Ubuntu's notification is still X instead of Z.
+  // Changing the filename constantly works around this problem
+  char filename[64];
+  SprintfLiteral(filename, "%d_%d.%s", getpid(), gImageNumber++,
+                 GetImageFileExtension(mMimeType.get()));
+
+  rv = mLocalImageFile->Append(NS_ConvertUTF8toUTF16(filename));
+  if (NS_FAILED(rv)) {
+    LOGMPRIS("Failed to create an image filename");
+    return false;
+  }
+
+  rv = mLocalImageFile->Create(nsIFile::NORMAL_FILE_TYPE, 0600);
+  if (NS_FAILED(rv)) {
+    LOGMPRIS("Failed to create an image file");
+    return false;
+  }
+
+  cleanup.release();
+  return true;
+}
+
+bool MPRISServiceHandler::InitLocalImageFolder() {
+  if (mLocalImageFolder && LocalImageFolderExists()) {
+    return true;
+  }
+
+  nsresult rv = NS_ERROR_FAILURE;
+  if (IsRunningUnderFlatpak()) {
+    // The XDG_DATA_HOME points to the same location in the host and guest
+    // filesystem.
+    if (const auto* xdgDataHome = g_getenv("XDG_DATA_HOME")) {
+      rv = NS_NewNativeLocalFile(nsDependentCString(xdgDataHome), true,
+                                 getter_AddRefs(mLocalImageFolder));
+    }
+  } else {
+    rv = NS_GetSpecialDirectory(XRE_USER_APP_DATA_DIR,
+                                getter_AddRefs(mLocalImageFolder));
+  }
+
+  if (NS_FAILED(rv) || !mLocalImageFolder) {
+    LOGMPRIS("Failed to get the image folder");
+    return false;
+  }
+
+  auto cleanup = MakeScopeExit([&] { mLocalImageFolder = nullptr; });
+
+  rv = mLocalImageFolder->Append(u"firefox-mpris"_ns);
+  if (NS_FAILED(rv)) {
+    LOGMPRIS("Failed to name an image folder");
+    return false;
+  }
+
+  if (!LocalImageFolderExists()) {
+    rv = mLocalImageFolder->Create(nsIFile::DIRECTORY_TYPE, 0700);
+    if (NS_FAILED(rv)) {
+      LOGMPRIS("Failed to create an image folder");
+      return false;
+    }
+  }
+
+  cleanup.release();
+  return true;
+}
+
+void MPRISServiceHandler::RemoveAllLocalImages() {
+  if (!mLocalImageFolder || !LocalImageFolderExists()) {
+    return;
+  }
+
+  nsresult rv = mLocalImageFolder->Remove(/* aRecursive */ true);
+  if (NS_FAILED(rv)) {
+    // It's ok to fail. The next removal is called when updating the
+    // media-session image, or closing the MPRIS.
+    LOGMPRIS("Failed to remove images");
+  }
+
+  LOGMPRIS("Abandon %s",
+           mLocalImageFile ? mLocalImageFile->NativePath().get() : "nothing");
+  mMPRISMetadata.mArtUrl.Truncate();
+  mLocalImageFile = nullptr;
+  mLocalImageFolder = nullptr;
+}
+
+bool MPRISServiceHandler::LocalImageFolderExists() {
+  MOZ_ASSERT(mLocalImageFolder);
+
+  bool exists;
+  nsresult rv = mLocalImageFolder->Exists(&exists);
+  return NS_SUCCEEDED(rv) && exists;
+}
+
+GVariant* MPRISServiceHandler::GetMetadataAsGVariant() const {
+  GVariantBuilder builder;
+  g_variant_builder_init(&builder, G_VARIANT_TYPE("a{sv}"));
+  g_variant_builder_add(&builder, "{sv}", "mpris:trackid",
+                        g_variant_new("o", DBUS_MPRIS_TRACK_PATH));
+
+  g_variant_builder_add(
+      &builder, "{sv}", "xesam:title",
+      g_variant_new_string(static_cast<const gchar*>(
+          NS_ConvertUTF16toUTF8(mMPRISMetadata.mTitle).get())));
+
+  g_variant_builder_add(
+      &builder, "{sv}", "xesam:album",
+      g_variant_new_string(static_cast<const gchar*>(
+          NS_ConvertUTF16toUTF8(mMPRISMetadata.mAlbum).get())));
+
+  GVariantBuilder artistBuilder;
+  g_variant_builder_init(&artistBuilder, G_VARIANT_TYPE("as"));
+  g_variant_builder_add(
+      &artistBuilder, "s",
+      static_cast<const gchar*>(
+          NS_ConvertUTF16toUTF8(mMPRISMetadata.mArtist).get()));
+  g_variant_builder_add(&builder, "{sv}", "xesam:artist",
+                        g_variant_builder_end(&artistBuilder));
+
+  if (!mMPRISMetadata.mArtUrl.IsEmpty()) {
+    g_variant_builder_add(&builder, "{sv}", "mpris:artUrl",
+                          g_variant_new_string(static_cast<const gchar*>(
+                              mMPRISMetadata.mArtUrl.get())));
+  }
+
+  return g_variant_builder_end(&builder);
+}
+
+void MPRISServiceHandler::EmitEvent(dom::MediaControlKey aKey) const {
+  for (const auto& listener : mListeners) {
+    listener->OnActionPerformed(dom::MediaControlAction(aKey));
+  }
+}
+
+struct InterfaceProperty {
+  const char* interface;
+  const char* property;
+};
+static const std::unordered_map<dom::MediaControlKey, InterfaceProperty>
+    gKeyProperty = {
+        {dom::MediaControlKey::Focus, {DBUS_MPRIS_INTERFACE, "CanRaise"}},
+        {dom::MediaControlKey::Nexttrack,
+         {DBUS_MPRIS_PLAYER_INTERFACE, "CanGoNext"}},
+        {dom::MediaControlKey::Previoustrack,
+         {DBUS_MPRIS_PLAYER_INTERFACE, "CanGoPrevious"}},
+        {dom::MediaControlKey::Play, {DBUS_MPRIS_PLAYER_INTERFACE, "CanPlay"}},
+        {dom::MediaControlKey::Pause,
+         {DBUS_MPRIS_PLAYER_INTERFACE, "CanPause"}}};
+
+void MPRISServiceHandler::SetSupportedMediaKeys(
+    const MediaKeysArray& aSupportedKeys) {
+  uint32_t supportedKeys = 0;
+  for (const dom::MediaControlKey& key : aSupportedKeys) {
+    supportedKeys |= GetMediaKeyMask(key);
+  }
+
+  if (mSupportedKeys == supportedKeys) {
+    LOGMPRIS("Supported keys stay the same");
+    return;
+  }
+
+  uint32_t oldSupportedKeys = mSupportedKeys;
+  mSupportedKeys = supportedKeys;
+
+  // Emit related property changes
+  for (auto it : gKeyProperty) {
+    bool keyWasSupported = oldSupportedKeys & GetMediaKeyMask(it.first);
+    bool keyIsSupported = mSupportedKeys & GetMediaKeyMask(it.first);
+    if (keyWasSupported != keyIsSupported) {
+      LOGMPRIS("Emit PropertiesChanged signal: %s.%s=%s", it.second.interface,
+               it.second.property, keyIsSupported ? "true" : "false");
+      EmitSupportedKeyChanged(it.first, keyIsSupported);
+    }
+  }
+}
+
+bool MPRISServiceHandler::IsMediaKeySupported(dom::MediaControlKey aKey) const {
+  return mSupportedKeys & GetMediaKeyMask(aKey);
+}
+
+bool MPRISServiceHandler::EmitSupportedKeyChanged(dom::MediaControlKey aKey,
+                                                  bool aSupported) const {
+  auto it = gKeyProperty.find(aKey);
+  if (it == gKeyProperty.end()) {
+    LOGMPRIS("No property for %s", ToMediaControlKeyStr(aKey));
+    return false;
+  }
+
+  GVariantBuilder builder;
+  g_variant_builder_init(&builder, G_VARIANT_TYPE("a{sv}"));
+  g_variant_builder_add(&builder, "{sv}",
+                        static_cast<const gchar*>(it->second.property),
+                        g_variant_new_boolean(aSupported));
+
+  GVariant* parameters = g_variant_new(
+      "(sa{sv}as)", static_cast<const gchar*>(it->second.interface), &builder,
+      nullptr);
+
+  LOGMPRIS("Emit MPRIS property changes for '%s.%s'", it->second.interface,
+           it->second.property);
+  return EmitPropertiesChangedSignal(parameters);
+}
+
+bool MPRISServiceHandler::EmitPropertiesChangedSignal(
+    GVariant* aParameters) const {
+  if (!mConnection) {
+    LOGMPRIS("No D-Bus Connection. Cannot emit properties changed signal");
+    return false;
+  }
+
+  GError* error = nullptr;
+  if (!g_dbus_connection_emit_signal(
+          mConnection, nullptr, DBUS_MPRIS_OBJECT_PATH,
+          "org.freedesktop.DBus.Properties", "PropertiesChanged", aParameters,
+          &error)) {
+    LOGMPRIS("Failed to emit MPRIS property changes: %s",
+             error ? error->message : "Unknown Error");
+    if (error) {
+      g_error_free(error);
+    }
+    return false;
+  }
+
+  return true;
+}
+
+#undef LOGMPRIS
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/gtk/MPRISServiceHandler.h b/widget/gtk/MPRISServiceHandler.h
new file mode 100644
index 0000000000..469090efc0
--- /dev/null
+++ b/widget/gtk/MPRISServiceHandler.h
@@ -0,0 +1,195 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_GTK_MPRIS_SERVICE_HANDLER_H_
+#define WIDGET_GTK_MPRIS_SERVICE_HANDLER_H_
+
+#include <gio/gio.h>
+#include "mozilla/dom/FetchImageHelper.h"
+#include "mozilla/dom/MediaControlKeySource.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/UniquePtr.h"
+#include "nsIFile.h"
+#include "nsMimeTypes.h"
+#include "nsString.h"
+
+#define DBUS_MPRIS_SERVICE_NAME "org.mpris.MediaPlayer2.firefox"
+#define DBUS_MPRIS_OBJECT_PATH "/org/mpris/MediaPlayer2"
+#define DBUS_MPRIS_INTERFACE "org.mpris.MediaPlayer2"
+#define DBUS_MPRIS_PLAYER_INTERFACE "org.mpris.MediaPlayer2.Player"
+#define DBUS_MPRIS_TRACK_PATH "/org/mpris/MediaPlayer2/firefox"
+
+namespace mozilla {
+namespace widget {
+
+/**
+ * This class implements the "MPRIS" D-Bus Service
+ * (https://specifications.freedesktop.org/mpris-spec/2.2),
+ * which is used to communicate with the Desktop Environment about the
+ * Multimedia playing in Gecko.
+ * Note that this interface requires many methods which may not be supported by
+ * Gecko, the interface
+ * however provides CanXYZ properties for these methods, so the method is
+ * defined but won't be executed.
+ *
+ * Also note that the following defines are for parts that the MPRIS Spec
+ * defines optional. The code won't
+ * compile with any of the defines set, yet, as those aren't implemented yet and
+ * probably never will be of
+ * use for gecko. For sake of completeness, they have been added until the
+ * decision about their implementation
+ * is finally made.
+ *
+ * The constexpr'ed methods are capabilities of the user agent known at compile
+ * time, e.g. we decided at
+ * compile time whether we ever want to support closing the user agent via MPRIS
+ * (Quit() and CanQuit()).
+ *
+ * Other properties like CanPlay() might depend on the runtime state (is there
+ * media available for playback?)
+ * and thus aren't a constexpr but merely a const method.
+ */
+class MPRISServiceHandler final : public dom::MediaControlKeySource {
+  NS_INLINE_DECL_REFCOUNTING(MPRISServiceHandler, override)
+ public:
+  // Note that this constructor does NOT initialize the MPRIS Service but only
+  // this class. The method Open() is responsible for registering and MAY FAIL.
+
+  MPRISServiceHandler();
+  bool Open() override;
+  void Close() override;
+  bool IsOpened() const override;
+
+  // From the EventSource.
+  void SetPlaybackState(dom::MediaSessionPlaybackState aState) override;
+
+  // GetPlaybackState returns dom::PlaybackState. GetPlaybackStatus returns this
+  // state converted into d-bus variants.
+  GVariant* GetPlaybackStatus() const;
+
+  const char* Identity() const;
+  const char* DesktopEntry() const;
+  bool PressKey(dom::MediaControlKey aKey) const;
+
+  void SetMediaMetadata(const dom::MediaMetadataBase& aMetadata) override;
+  GVariant* GetMetadataAsGVariant() const;
+
+  void SetSupportedMediaKeys(const MediaKeysArray& aSupportedKeys) override;
+
+  bool IsMediaKeySupported(dom::MediaControlKey aKey) const;
+
+  void OwnName(GDBusConnection* aConnection);
+
+ private:
+  ~MPRISServiceHandler();
+
+  // Note: Registration Ids for the D-Bus start with 1, so a value of 0
+  // indicates an error (or an object which wasn't initialized yet)
+
+  // a handle to our bus registration/ownership
+  guint mOwnerId = 0;
+  // This is for the interface org.mpris.MediaPlayer2
+  guint mRootRegistrationId = 0;
+  // This is for the interface org.mpris.MediaPlayer2.Player
+  guint mPlayerRegistrationId = 0;
+  RefPtr<GDBusNodeInfo> mIntrospectionData;
+  GDBusConnection* mConnection = nullptr;
+  bool mInitialized = false;
+  nsAutoCString mIdentity;
+  nsAutoCString mDesktopEntry;
+
+  // The image format used in MPRIS is based on the mMimeType here. Although
+  // IMAGE_JPEG or IMAGE_BMP are valid types as well but a png image with
+  // transparent background will be converted into a jpeg/bmp file with a
+  // colored background IMAGE_PNG format seems to be the best choice for now.
+  nsCString mMimeType{IMAGE_PNG};
+
+  // A bitmask indicating what keys are enabled
+  uint32_t mSupportedKeys = 0;
+
+  class MPRISMetadata : public dom::MediaMetadataBase {
+   public:
+    MPRISMetadata() = default;
+    ~MPRISMetadata() = default;
+
+    void UpdateFromMetadataBase(const dom::MediaMetadataBase& aMetadata) {
+      mTitle = aMetadata.mTitle;
+      mArtist = aMetadata.mArtist;
+      mAlbum = aMetadata.mAlbum;
+      mArtwork = aMetadata.mArtwork;
+    }
+    void Clear() {
+      UpdateFromMetadataBase(MediaMetadataBase::EmptyData());
+      mArtUrl.Truncate();
+    }
+
+    nsCString mArtUrl;
+  };
+  MPRISMetadata mMPRISMetadata;
+
+  // The saved image file fetched from the URL
+  nsCOMPtr<nsIFile> mLocalImageFile;
+  nsCOMPtr<nsIFile> mLocalImageFolder;
+
+  UniquePtr<dom::FetchImageHelper> mImageFetcher;
+  MozPromiseRequestHolder<dom::ImagePromise> mImageFetchRequest;
+
+  nsString mFetchingUrl;
+  nsString mCurrentImageUrl;
+
+  size_t mNextImageIndex = 0;
+
+  // Load the image at index aIndex of the metadta's artwork to MPRIS
+  // asynchronously
+  void LoadImageAtIndex(const size_t aIndex);
+  bool SetImageToDisplay(const char* aImageData, uint32_t aDataSize);
+
+  bool RenewLocalImageFile(const char* aImageData, uint32_t aDataSize);
+  bool InitLocalImageFile();
+  bool InitLocalImageFolder();
+  void RemoveAllLocalImages();
+  bool LocalImageFolderExists();
+
+  // Queries nsAppInfo to get the branded browser name and vendor
+  void InitIdentity();
+
+  // non-public API, called from events
+  void OnNameAcquired(GDBusConnection* aConnection, const gchar* aName);
+  void OnNameLost(GDBusConnection* aConnection, const gchar* aName);
+  void OnBusAcquired(GDBusConnection* aConnection, const gchar* aName);
+
+  static void OnNameAcquiredStatic(GDBusConnection* aConnection,
+                                   const gchar* aName, gpointer aUserData);
+  static void OnNameLostStatic(GDBusConnection* aConnection, const gchar* aName,
+                               gpointer aUserData);
+  static void OnBusAcquiredStatic(GDBusConnection* aConnection,
+                                  const gchar* aName, gpointer aUserData);
+
+  void EmitEvent(dom::MediaControlKey aKey) const;
+
+  bool EmitMetadataChanged() const;
+
+  void SetMediaMetadataInternal(const dom::MediaMetadataBase& aMetadata,
+                                bool aClearArtUrl = true);
+
+  bool EmitSupportedKeyChanged(dom::MediaControlKey aKey,
+                               bool aSupported) const;
+
+  bool EmitPropertiesChangedSignal(GVariant* aParameters) const;
+
+  void ClearMetadata();
+
+  RefPtr<GCancellable> mDBusGetCancellable;
+
+  nsCString mServiceName;
+  void SetServiceName(const char* aName);
+  const char* GetServiceName();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // WIDGET_GTK_MPRIS_SERVICE_HANDLER_H_
diff --git a/widget/gtk/MediaKeysEventSourceFactory.cpp b/widget/gtk/MediaKeysEventSourceFactory.cpp
new file mode 100644
index 0000000000..b9a3dfde41
--- /dev/null
+++ b/widget/gtk/MediaKeysEventSourceFactory.cpp
@@ -0,0 +1,14 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaKeysEventSourceFactory.h"
+#include "MPRISServiceHandler.h"
+
+namespace mozilla::widget {
+
+mozilla::dom::MediaControlKeySource* CreateMediaControlKeySource() {
+  return new MPRISServiceHandler();
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/MozContainer.cpp b/widget/gtk/MozContainer.cpp
new file mode 100644
index 0000000000..95d32b57b4
--- /dev/null
+++ b/widget/gtk/MozContainer.cpp
@@ -0,0 +1,402 @@
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MozContainer.h"
+
+#include <glib.h>
+#include <gtk/gtk.h>
+#include <stdio.h>
+#include "mozilla/WidgetUtilsGtk.h"
+#include "nsWindow.h"
+
+#ifdef MOZ_LOGGING
+#  include "mozilla/Logging.h"
+#  include "nsTArray.h"
+#  include "Units.h"
+extern mozilla::LazyLogModule gWidgetLog;
+#  define LOGCONTAINER(args) MOZ_LOG(gWidgetLog, mozilla::LogLevel::Debug, args)
+#else
+#  define LOGCONTAINER(args)
+#endif /* MOZ_LOGGING */
+
+/* init methods */
+void moz_container_class_init(MozContainerClass* klass);
+static void moz_container_init(MozContainer* container);
+
+/* widget class methods */
+static void moz_container_map(GtkWidget* widget);
+void moz_container_unmap(GtkWidget* widget);
+static void moz_container_size_allocate(GtkWidget* widget,
+                                        GtkAllocation* allocation);
+static void moz_container_realize(GtkWidget* widget);
+static void moz_container_unrealize(GtkWidget* widget);
+
+/* container class methods */
+static void moz_container_remove(GtkContainer* container,
+                                 GtkWidget* child_widget);
+static void moz_container_forall(GtkContainer* container,
+                                 gboolean include_internals,
+                                 GtkCallback callback, gpointer callback_data);
+static void moz_container_add(GtkContainer* container, GtkWidget* widget);
+
+typedef struct _MozContainerChild MozContainerChild;
+
+struct _MozContainerChild {
+  GtkWidget* widget;
+  gint x;
+  gint y;
+};
+
+static void moz_container_allocate_child(MozContainer* container,
+                                         MozContainerChild* child);
+static MozContainerChild* moz_container_get_child(MozContainer* container,
+                                                  GtkWidget* child);
+
+/* public methods */
+
+GType moz_container_get_type(void) {
+  static GType moz_container_type = 0;
+
+  if (!moz_container_type) {
+    static GTypeInfo moz_container_info = {
+        sizeof(MozContainerClass),                /* class_size */
+        NULL,                                     /* base_init */
+        NULL,                                     /* base_finalize */
+        (GClassInitFunc)moz_container_class_init, /* class_init */
+        NULL,                                     /* class_destroy */
+        NULL,                                     /* class_data */
+        sizeof(MozContainer),                     /* instance_size */
+        0,                                        /* n_preallocs */
+        (GInstanceInitFunc)moz_container_init,    /* instance_init */
+        NULL,                                     /* value_table */
+    };
+
+    moz_container_type =
+        g_type_register_static(GTK_TYPE_CONTAINER, "MozContainer",
+                               &moz_container_info, static_cast<GTypeFlags>(0));
+  }
+
+  return moz_container_type;
+}
+
+GtkWidget* moz_container_new(void) {
+  MozContainer* container;
+
+  container =
+      static_cast<MozContainer*>(g_object_new(MOZ_CONTAINER_TYPE, nullptr));
+
+  return GTK_WIDGET(container);
+}
+
+void moz_container_put(MozContainer* container, GtkWidget* child_widget, gint x,
+                       gint y) {
+  MozContainerChild* child;
+
+  child = g_new(MozContainerChild, 1);
+
+  child->widget = child_widget;
+  child->x = x;
+  child->y = y;
+
+  /*  printf("moz_container_put %p %p %d %d\n", (void *)container,
+      (void *)child_widget, x, y); */
+
+  container->data.children = g_list_append(container->data.children, child);
+
+  /* we assume that the caller of this function will have already set
+     the parent GdkWindow because we can have many anonymous children. */
+  gtk_widget_set_parent(child_widget, GTK_WIDGET(container));
+}
+
+static void moz_container_destroy(GtkWidget* widget) {
+  auto* container = MOZ_CONTAINER(widget);
+  if (container->destroyed) {
+    return;  // The destroy signal may run multiple times.
+  }
+  LOGCONTAINER(("moz_container_destroy() [%p]\n",
+                (void*)moz_container_get_nsWindow(MOZ_CONTAINER(widget))));
+  container->destroyed = TRUE;
+  container->data.~Data();
+}
+
+void moz_container_class_init(MozContainerClass* klass) {
+  /*GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+    GtkObjectClass *object_class = GTK_OBJECT_CLASS (klass); */
+  GtkContainerClass* container_class = GTK_CONTAINER_CLASS(klass);
+  GtkWidgetClass* widget_class = GTK_WIDGET_CLASS(klass);
+
+  widget_class->realize = moz_container_realize;
+  widget_class->unrealize = moz_container_unrealize;
+  widget_class->destroy = moz_container_destroy;
+
+#ifdef MOZ_WAYLAND
+  if (mozilla::widget::GdkIsWaylandDisplay()) {
+    widget_class->map = moz_container_wayland_map;
+    widget_class->size_allocate = moz_container_wayland_size_allocate;
+    widget_class->map_event = moz_container_wayland_map_event;
+    widget_class->unmap = moz_container_wayland_unmap;
+  } else {
+#endif
+    widget_class->map = moz_container_map;
+    widget_class->size_allocate = moz_container_size_allocate;
+    widget_class->unmap = moz_container_unmap;
+#ifdef MOZ_WAYLAND
+  }
+#endif
+
+  container_class->remove = moz_container_remove;
+  container_class->forall = moz_container_forall;
+  container_class->add = moz_container_add;
+}
+
+void moz_container_init(MozContainer* container) {
+  container->destroyed = FALSE;
+  new (&container->data) MozContainer::Data();
+  gtk_widget_set_can_focus(GTK_WIDGET(container), TRUE);
+  gtk_widget_set_redraw_on_allocate(GTK_WIDGET(container), FALSE);
+  LOGCONTAINER(("%s [%p]\n", __FUNCTION__,
+                (void*)moz_container_get_nsWindow(container)));
+}
+
+void moz_container_map(GtkWidget* widget) {
+  MozContainer* container;
+  GList* tmp_list;
+  GtkWidget* tmp_child;
+
+  g_return_if_fail(IS_MOZ_CONTAINER(widget));
+  container = MOZ_CONTAINER(widget);
+
+  LOGCONTAINER(("moz_container_map() [%p]",
+                (void*)moz_container_get_nsWindow(container)));
+
+  gtk_widget_set_mapped(widget, TRUE);
+
+  tmp_list = container->data.children;
+  while (tmp_list) {
+    tmp_child = ((MozContainerChild*)tmp_list->data)->widget;
+
+    if (gtk_widget_get_visible(tmp_child)) {
+      if (!gtk_widget_get_mapped(tmp_child)) gtk_widget_map(tmp_child);
+    }
+    tmp_list = tmp_list->next;
+  }
+
+  if (gtk_widget_get_has_window(widget)) {
+    gdk_window_show(gtk_widget_get_window(widget));
+  }
+}
+
+void moz_container_unmap(GtkWidget* widget) {
+  g_return_if_fail(IS_MOZ_CONTAINER(widget));
+
+  LOGCONTAINER(("moz_container_unmap() [%p]",
+                (void*)moz_container_get_nsWindow(MOZ_CONTAINER(widget))));
+
+  // Disable rendering to MozContainer before we unmap it.
+  nsWindow* window = moz_container_get_nsWindow(MOZ_CONTAINER(widget));
+  window->DisableRendering();
+
+  gtk_widget_set_mapped(widget, FALSE);
+
+  if (gtk_widget_get_has_window(widget)) {
+    gdk_window_hide(gtk_widget_get_window(widget));
+  }
+}
+
+void moz_container_realize(GtkWidget* widget) {
+  GdkWindow* parent = gtk_widget_get_parent_window(widget);
+  GdkWindow* window;
+
+  gtk_widget_set_realized(widget, TRUE);
+
+  GdkWindowAttr attributes;
+  gint attributes_mask = GDK_WA_VISUAL | GDK_WA_X | GDK_WA_Y;
+  GtkAllocation allocation;
+
+  gtk_widget_get_allocation(widget, &allocation);
+  attributes.event_mask = gtk_widget_get_events(widget);
+  attributes.x = allocation.x;
+  attributes.y = allocation.y;
+  attributes.width = allocation.width;
+  attributes.height = allocation.height;
+  attributes.wclass = GDK_INPUT_OUTPUT;
+  attributes.window_type = GDK_WINDOW_CHILD;
+  MozContainer* container = MOZ_CONTAINER(widget);
+  attributes.visual =
+      container->data.force_default_visual
+          ? gdk_screen_get_system_visual(gtk_widget_get_screen(widget))
+          : gtk_widget_get_visual(widget);
+
+  window = gdk_window_new(parent, &attributes, attributes_mask);
+
+  LOGCONTAINER(("moz_container_realize() [%p] GdkWindow %p\n",
+                (void*)moz_container_get_nsWindow(container), (void*)window));
+
+  gtk_widget_register_window(widget, window);
+  gtk_widget_set_window(widget, window);
+}
+
+void moz_container_unrealize(GtkWidget* widget) {
+  GdkWindow* window = gtk_widget_get_window(widget);
+  LOGCONTAINER(("moz_container_unrealize() [%p] GdkWindow %p\n",
+                (void*)moz_container_get_nsWindow(MOZ_CONTAINER(widget)),
+                (void*)window));
+
+  if (gtk_widget_get_mapped(widget)) {
+    gtk_widget_unmap(widget);
+  }
+
+  gtk_widget_unregister_window(widget, window);
+  gtk_widget_set_window(widget, nullptr);
+  gdk_window_destroy(window);
+  gtk_widget_set_realized(widget, false);
+}
+
+void moz_container_size_allocate(GtkWidget* widget, GtkAllocation* allocation) {
+  MozContainer* container;
+  GList* tmp_list;
+  GtkAllocation tmp_allocation;
+
+  g_return_if_fail(IS_MOZ_CONTAINER(widget));
+
+  LOGCONTAINER(("moz_container_size_allocate [%p] %d,%d -> %d x %d\n",
+                (void*)moz_container_get_nsWindow(MOZ_CONTAINER(widget)),
+                allocation->x, allocation->y, allocation->width,
+                allocation->height));
+
+  /* short circuit if you can */
+  container = MOZ_CONTAINER(widget);
+  gtk_widget_get_allocation(widget, &tmp_allocation);
+  if (!container->data.children && tmp_allocation.x == allocation->x &&
+      tmp_allocation.y == allocation->y &&
+      tmp_allocation.width == allocation->width &&
+      tmp_allocation.height == allocation->height) {
+    return;
+  }
+
+  gtk_widget_set_allocation(widget, allocation);
+
+  tmp_list = container->data.children;
+
+  while (tmp_list) {
+    MozContainerChild* child = static_cast<MozContainerChild*>(tmp_list->data);
+
+    moz_container_allocate_child(container, child);
+
+    tmp_list = tmp_list->next;
+  }
+
+  if (gtk_widget_get_has_window(widget) && gtk_widget_get_realized(widget)) {
+    gdk_window_move_resize(gtk_widget_get_window(widget), allocation->x,
+                           allocation->y, allocation->width,
+                           allocation->height);
+  }
+}
+
+void moz_container_remove(GtkContainer* container, GtkWidget* child_widget) {
+  MozContainerChild* child;
+  MozContainer* moz_container;
+  GdkWindow* parent_window;
+
+  g_return_if_fail(IS_MOZ_CONTAINER(container));
+  g_return_if_fail(GTK_IS_WIDGET(child_widget));
+
+  moz_container = MOZ_CONTAINER(container);
+
+  child = moz_container_get_child(moz_container, child_widget);
+  g_return_if_fail(child);
+
+  /* gtk_widget_unparent will remove the parent window (as well as the
+   * parent widget), but, in Mozilla's window hierarchy, the parent window
+   * may need to be kept because it may be part of a GdkWindow sub-hierarchy
+   * that is being moved to another MozContainer.
+   *
+   * (In a conventional GtkWidget hierarchy, GdkWindows being reparented
+   * would have their own GtkWidget and that widget would be the one being
+   * reparented.  In Mozilla's hierarchy, the parent_window needs to be
+   * retained so that the GdkWindow sub-hierarchy is maintained.)
+   */
+  parent_window = gtk_widget_get_parent_window(child_widget);
+  if (parent_window) g_object_ref(parent_window);
+
+  gtk_widget_unparent(child_widget);
+
+  if (parent_window) {
+    /* The child_widget will always still exist because g_signal_emit,
+     * which invokes this function, holds a reference.
+     *
+     * If parent_window is the container's root window then it will not be
+     * the parent_window if the child_widget is placed in another
+     * container.
+     */
+    if (parent_window != gtk_widget_get_window(GTK_WIDGET(container))) {
+      gtk_widget_set_parent_window(child_widget, parent_window);
+    }
+
+    g_object_unref(parent_window);
+  }
+
+  moz_container->data.children =
+      g_list_remove(moz_container->data.children, child);
+  g_free(child);
+}
+
+void moz_container_forall(GtkContainer* container, gboolean include_internals,
+                          GtkCallback callback, gpointer callback_data) {
+  g_return_if_fail(IS_MOZ_CONTAINER(container));
+  g_return_if_fail(callback);
+
+  MozContainer* moz_container = MOZ_CONTAINER(container);
+
+  GList* tmp_list = moz_container->data.children;
+  while (tmp_list) {
+    MozContainerChild* child;
+    child = static_cast<MozContainerChild*>(tmp_list->data);
+    tmp_list = tmp_list->next;
+    (*callback)(child->widget, callback_data);
+  }
+}
+
+static void moz_container_allocate_child(MozContainer* container,
+                                         MozContainerChild* child) {
+  GtkAllocation allocation;
+
+  gtk_widget_get_allocation(child->widget, &allocation);
+  allocation.x = child->x;
+  allocation.y = child->y;
+
+  gtk_widget_size_allocate(child->widget, &allocation);
+}
+
+MozContainerChild* moz_container_get_child(MozContainer* container,
+                                           GtkWidget* child_widget) {
+  GList* tmp_list = container->data.children;
+  while (tmp_list) {
+    MozContainerChild* child;
+
+    child = static_cast<MozContainerChild*>(tmp_list->data);
+    tmp_list = tmp_list->next;
+
+    if (child->widget == child_widget) return child;
+  }
+  return nullptr;
+}
+
+static void moz_container_add(GtkContainer* container, GtkWidget* widget) {
+  moz_container_put(MOZ_CONTAINER(container), widget, 0, 0);
+}
+
+void moz_container_force_default_visual(MozContainer* container) {
+  container->data.force_default_visual = true;
+}
+
+nsWindow* moz_container_get_nsWindow(MozContainer* container) {
+  gpointer user_data = g_object_get_data(G_OBJECT(container), "nsWindow");
+  return static_cast<nsWindow*>(user_data);
+}
+
+#undef LOGCONTAINER
diff --git a/widget/gtk/MozContainer.h b/widget/gtk/MozContainer.h
new file mode 100644
index 0000000000..27fa2a701f
--- /dev/null
+++ b/widget/gtk/MozContainer.h
@@ -0,0 +1,97 @@
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __MOZ_CONTAINER_H__
+#define __MOZ_CONTAINER_H__
+
+#ifdef MOZ_WAYLAND
+#  include "MozContainerWayland.h"
+#endif
+
+#include <gtk/gtk.h>
+#include <functional>
+
+/*
+ * MozContainer
+ *
+ * This class serves three purposes in the nsIWidget implementation.
+ *
+ *   - It provides objects to receive signals from GTK for events on native
+ *     windows.
+ *
+ *   - It provides GdkWindow to draw content on Wayland or when Gtk+ renders
+ *     client side decorations to mShell.
+ *
+ *   - It provides a container parent for GtkWidgets.  The only GtkWidgets
+ *     that need this in Mozilla are the GtkSockets for windowed plugins (Xt
+ *     and XEmbed).
+ *
+ * Note that the window hierarchy in Mozilla differs from conventional
+ * GtkWidget hierarchies.
+ *
+ * Mozilla's hierarchy exists through the GdkWindow hierarchy, and all child
+ * GdkWindows (within a child nsIWidget hierarchy) belong to one MozContainer
+ * GtkWidget.  If the MozContainer is unrealized or its GdkWindows are
+ * destroyed for some other reason, then the hierarchy no longer exists.  (In
+ * conventional GTK clients, the hierarchy is recorded by the GtkWidgets, and
+ * so can be re-established after destruction of the GdkWindows.)
+ *
+ * One consequence of this is that the MozContainer does not know which of its
+ * GdkWindows should parent child GtkWidgets.  (Conventional GtkContainers
+ * determine which GdkWindow to assign child GtkWidgets.)
+ *
+ * Therefore, when adding a child GtkWidget to a MozContainer,
+ * gtk_widget_set_parent_window should be called on the child GtkWidget before
+ * it is realized.
+ */
+
+#define MOZ_CONTAINER_TYPE (moz_container_get_type())
+#define MOZ_CONTAINER(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj), MOZ_CONTAINER_TYPE, MozContainer))
+#define MOZ_CONTAINER_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass), MOZ_CONTAINER_TYPE, MozContainerClass))
+#define IS_MOZ_CONTAINER(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj), MOZ_CONTAINER_TYPE))
+#define IS_MOZ_CONTAINER_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass), MOZ_CONTAINER_TYPE))
+#define MOZ_CONTAINER_GET_CLASS(obj) \
+  (G_TYPE_INSTANCE_GET_CLASS((obj), MOZ_CONTAINER_TYPE, MozContainerClass))
+#ifdef MOZ_WAYLAND
+#  define MOZ_WL_CONTAINER(obj) (&MOZ_CONTAINER(obj)->data.wl_container)
+#endif
+
+typedef struct _MozContainer MozContainer;
+typedef struct _MozContainerClass MozContainerClass;
+
+struct _MozContainer {
+  GtkContainer container;
+  gboolean destroyed;
+  struct Data {
+    GList* children = nullptr;
+    gboolean force_default_visual = false;
+#ifdef MOZ_WAYLAND
+    MozContainerWayland wl_container;
+#endif
+  } data;
+};
+
+struct _MozContainerClass {
+  GtkContainerClass parent_class;
+};
+
+GType moz_container_get_type(void);
+GtkWidget* moz_container_new(void);
+void moz_container_unmap(GtkWidget* widget);
+void moz_container_put(MozContainer* container, GtkWidget* child_widget, gint x,
+                       gint y);
+void moz_container_force_default_visual(MozContainer* container);
+void moz_container_class_init(MozContainerClass* klass);
+
+class nsWindow;
+nsWindow* moz_container_get_nsWindow(MozContainer* container);
+
+#endif /* __MOZ_CONTAINER_H__ */
diff --git a/widget/gtk/MozContainerWayland.cpp b/widget/gtk/MozContainerWayland.cpp
new file mode 100644
index 0000000000..0e50a3f27c
--- /dev/null
+++ b/widget/gtk/MozContainerWayland.cpp
@@ -0,0 +1,824 @@
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+/*
+ * MozContainerWayland is a wrapper over MozContainer which provides
+ * wl_surface for MozContainer widget.
+ *
+ * The widget scheme looks like:
+ *
+ *   ---------------------------------------------------------
+ *  |  mShell Gtk widget (contains wl_surface owned by Gtk+)  |
+ *  |                                                         |
+ *  |  ---------------------------------------------------    |
+ *  | | mContainer (contains wl_surface owned by Gtk+)    |   |
+ *  | |                                                   |   |
+ *  | |  ---------------------------------------------    |   |
+ *  | | | wl_subsurface (attached to wl_surface       |   |   |
+ *  | | |                of mContainer)               |   |   |
+ *  | | |                                             |   |   |
+ *  | | |                                             |   |   |
+ *  | |  ---------------------------------------------    |   |
+ *  |  ---------------------------------------------------    |
+ *   ---------------------------------------------------------
+ *
+ *  We draw to wl_subsurface owned by MozContainerWayland.
+ *  We need to wait until wl_surface of mContainer is created
+ *  and then we create and attach our wl_subsurface to it.
+ *
+ *  First wl_subsurface creation has these steps:
+ *
+ *  1) moz_container_wayland_size_allocate() handler is called when
+ *     mContainer size/position is known.
+ *     It calls moz_container_wayland_surface_create_locked(), registers
+ *     a frame callback handler
+ *     moz_container_wayland_frame_callback_handler().
+ *
+ *  2) moz_container_wayland_frame_callback_handler() is called
+ *     when wl_surface owned by mozContainer is ready.
+ *     We call initial_draw_cbs() handler and we can create our wl_subsurface
+ *     on top of wl_surface owned by mozContainer.
+ *
+ *  When MozContainer hides/show again, moz_container_wayland_size_allocate()
+ *  handler may not be called as MozContainer size is set. So after first
+ *  show/hide sequence use moz_container_wayland_map_event() to create
+ *  wl_subsurface of MozContainer.
+ */
+
+#include "MozContainer.h"
+
+#include <dlfcn.h>
+#include <glib.h>
+#include <stdio.h>
+#include <wayland-egl.h>
+
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsGtkUtils.h"
+#include "nsWaylandDisplay.h"
+#include "base/task.h"
+
+#ifdef MOZ_LOGGING
+
+#  include "mozilla/Logging.h"
+#  include "nsTArray.h"
+#  include "Units.h"
+#  include "nsWindow.h"
+extern mozilla::LazyLogModule gWidgetWaylandLog;
+extern mozilla::LazyLogModule gWidgetLog;
+#  define LOGWAYLAND(...) \
+    MOZ_LOG(gWidgetWaylandLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#  define LOGCONTAINER(...) \
+    MOZ_LOG(gWidgetLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#else
+#  define LOGWAYLAND(...)
+#  define LOGCONTAINER(...)
+#endif /* MOZ_LOGGING */
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+static bool moz_container_wayland_surface_create_locked(
+    const MutexAutoLock& aProofOfLock, MozContainer* container);
+static void moz_container_wayland_set_opaque_region_locked(
+    const MutexAutoLock& aProofOfLock, MozContainer* container);
+
+// Lock mozcontainer and get wayland surface of it. You need to pair with
+// moz_container_wayland_surface_unlock() even
+// if moz_container_wayland_surface_lock() fails and returns nullptr.
+static struct wl_surface* moz_container_wayland_surface_lock(
+    MozContainer* container);
+static void moz_container_wayland_surface_unlock(MozContainer* container,
+                                                 struct wl_surface** surface);
+
+MozContainerSurfaceLock::MozContainerSurfaceLock(MozContainer* aContainer) {
+  mContainer = aContainer;
+  mSurface = moz_container_wayland_surface_lock(aContainer);
+}
+MozContainerSurfaceLock::~MozContainerSurfaceLock() {
+  moz_container_wayland_surface_unlock(mContainer, &mSurface);
+}
+struct wl_surface* MozContainerSurfaceLock::GetSurface() { return mSurface; }
+
+// Invalidate gtk wl_surface to commit changes to wl_subsurface.
+// wl_subsurface changes are effective when parent surface is commited.
+static void moz_container_wayland_invalidate(MozContainer* container) {
+  LOGWAYLAND("moz_container_wayland_invalidate [%p]\n",
+             (void*)moz_container_get_nsWindow(container));
+
+  GdkWindow* window = gtk_widget_get_window(GTK_WIDGET(container));
+  if (!window) {
+    LOGWAYLAND("    Failed - missing GdkWindow!\n");
+    return;
+  }
+  gdk_window_invalidate_rect(window, nullptr, true);
+}
+
+// Route input to parent wl_surface owned by Gtk+ so we get input
+// events from Gtk+.
+static void moz_container_clear_input_region(MozContainer* container) {
+  struct wl_compositor* compositor = WaylandDisplayGet()->GetCompositor();
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  wl_region* region = wl_compositor_create_region(compositor);
+  wl_surface_set_input_region(wl_container->surface, region);
+  wl_region_destroy(region);
+}
+
+static void moz_container_wayland_move_locked(const MutexAutoLock& aProofOfLock,
+                                              MozContainer* container, int dx,
+                                              int dy) {
+  LOGCONTAINER("moz_container_wayland_move [%p] %d,%d\n",
+               (void*)moz_container_get_nsWindow(container), dx, dy);
+
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  if (!wl_container->subsurface || (wl_container->subsurface_dx == dx &&
+                                    wl_container->subsurface_dy == dy)) {
+    return;
+  }
+
+  wl_container->subsurface_dx = dx;
+  wl_container->subsurface_dy = dy;
+  wl_subsurface_set_position(wl_container->subsurface,
+                             wl_container->subsurface_dx,
+                             wl_container->subsurface_dy);
+}
+
+// This is called from layout/compositor code only with
+// size equal to GL rendering context.
+
+// Return false if scale factor doesn't match buffer size.
+// We need to skip painting in such case do avoid Wayland compositor freaking.
+bool moz_container_wayland_egl_window_set_size(MozContainer* container,
+                                               nsIntSize aSize, int aScale) {
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  MutexAutoLock lock(wl_container->container_lock);
+
+  // We may be called after unmap so we're missing egl window completelly.
+  // In such case don't return false which would block compositor.
+  // We return true here and don't block flush WebRender queue.
+  // We'll be repainted if our window become visible again anyway.
+  if (!wl_container->eglwindow) {
+    return true;
+  }
+
+  if (wl_container->buffer_scale != aScale) {
+    moz_container_wayland_set_scale_factor_locked(lock, container, aScale);
+  }
+
+  /* Enable for size changes logging
+    LOGCONTAINER(
+        "moz_container_wayland_egl_window_set_size [%p] %d x %d scale %d "
+        "(unscaled %d x %d)",
+        (void*)moz_container_get_nsWindow(container), aSize.width, aSize.height,
+        aScale, aSize.width / aScale, aSize.height / aScale);
+  */
+  wl_egl_window_resize(wl_container->eglwindow, aSize.width, aSize.height, 0,
+                       0);
+
+  return moz_container_wayland_size_matches_scale_factor_locked(
+      lock, container, aSize.width, aSize.height);
+}
+
+void moz_container_wayland_add_initial_draw_callback_locked(
+    MozContainer* container, const std::function<void(void)>& initial_draw_cb) {
+  MozContainerWayland* wl_container = &container->data.wl_container;
+
+  if (wl_container->ready_to_draw && !wl_container->surface) {
+    NS_WARNING(
+        "moz_container_wayland_add_or_fire_initial_draw_callback:"
+        " ready to draw without wayland surface!");
+  }
+  MOZ_DIAGNOSTIC_ASSERT(!wl_container->ready_to_draw || !wl_container->surface);
+  wl_container->initial_draw_cbs.push_back(initial_draw_cb);
+}
+
+void moz_container_wayland_add_or_fire_initial_draw_callback(
+    MozContainer* container, const std::function<void(void)>& initial_draw_cb) {
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  {
+    MutexAutoLock lock(wl_container->container_lock);
+    if (wl_container->ready_to_draw && !wl_container->surface) {
+      NS_WARNING(
+          "moz_container_wayland_add_or_fire_initial_draw_callback: ready to "
+          "draw "
+          "without wayland surface!");
+    }
+    if (!wl_container->ready_to_draw || !wl_container->surface) {
+      wl_container->initial_draw_cbs.push_back(initial_draw_cb);
+      return;
+    }
+  }
+
+  // We're ready to draw as
+  // wl_container->ready_to_draw && wl_container->surface
+  // call the callback directly instead of store them.
+  initial_draw_cb();
+}
+
+static void moz_container_wayland_clear_initial_draw_callback_locked(
+    const MutexAutoLock& aProofOfLock, MozContainer* container) {
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  MozClearPointer(wl_container->frame_callback_handler, wl_callback_destroy);
+  wl_container->initial_draw_cbs.clear();
+}
+
+void moz_container_wayland_clear_initial_draw_callback(
+    MozContainer* container) {
+  MutexAutoLock lock(container->data.wl_container.container_lock);
+  moz_container_wayland_clear_initial_draw_callback_locked(lock, container);
+}
+
+static void moz_container_wayland_frame_callback_handler(
+    void* data, struct wl_callback* callback, uint32_t time) {
+  MozContainerWayland* wl_container = MOZ_WL_CONTAINER(data);
+
+  LOGWAYLAND(
+      "%s [%p] frame_callback_handler %p ready_to_draw %d (set to true)"
+      " initial_draw callback %zd\n",
+      __FUNCTION__, (void*)moz_container_get_nsWindow(MOZ_CONTAINER(data)),
+      (void*)wl_container->frame_callback_handler, wl_container->ready_to_draw,
+      wl_container->initial_draw_cbs.size());
+
+  std::vector<std::function<void(void)>> cbs;
+  {
+    // Protect mozcontainer internals changes by container_lock.
+    MutexAutoLock lock(wl_container->container_lock);
+    MozClearPointer(wl_container->frame_callback_handler, wl_callback_destroy);
+    // It's possible that container is already unmapped so quit in such case.
+    if (!wl_container->surface) {
+      LOGWAYLAND("  container is unmapped, quit.");
+      if (!wl_container->initial_draw_cbs.empty()) {
+        NS_WARNING("Unmapping MozContainer with active draw callback!");
+        wl_container->initial_draw_cbs.clear();
+      }
+      return;
+    }
+    if (wl_container->ready_to_draw) {
+      return;
+    }
+    wl_container->ready_to_draw = true;
+    cbs = std::move(wl_container->initial_draw_cbs);
+  }
+
+  // Call the callbacks registered by
+  // moz_container_wayland_add_or_fire_initial_draw_callback().
+  // and we can't do that under mozcontainer lock.
+  for (auto const& cb : cbs) {
+    cb();
+  }
+}
+
+static const struct wl_callback_listener moz_container_frame_listener = {
+    moz_container_wayland_frame_callback_handler};
+
+static void after_frame_clock_after_paint(GdkFrameClock* clock,
+                                          MozContainer* container) {
+  MozContainerSurfaceLock lock(container);
+  struct wl_surface* surface = lock.GetSurface();
+  if (surface) {
+    wl_surface_commit(surface);
+  }
+}
+
+static bool moz_gdk_wayland_window_add_frame_callback_surface_locked(
+    const MutexAutoLock& aProofOfLock, MozContainer* container) {
+  static auto sGdkWaylandWindowAddCallbackSurface =
+      (void (*)(GdkWindow*, struct wl_surface*))dlsym(
+          RTLD_DEFAULT, "gdk_wayland_window_add_frame_callback_surface");
+
+  if (!StaticPrefs::widget_wayland_opaque_region_enabled_AtStartup() ||
+      !sGdkWaylandWindowAddCallbackSurface) {
+    return false;
+  }
+
+  GdkWindow* window = gtk_widget_get_window(GTK_WIDGET(container));
+  MozContainerWayland* wl_container = &container->data.wl_container;
+
+  sGdkWaylandWindowAddCallbackSurface(window, wl_container->surface);
+
+  GdkFrameClock* frame_clock = gdk_window_get_frame_clock(window);
+  g_signal_connect_after(frame_clock, "after-paint",
+                         G_CALLBACK(after_frame_clock_after_paint), container);
+  return true;
+}
+
+static void moz_gdk_wayland_window_remove_frame_callback_surface_locked(
+    const MutexAutoLock& aProofOfLock, MozContainer* container) {
+  static auto sGdkWaylandWindowRemoveCallbackSurface =
+      (void (*)(GdkWindow*, struct wl_surface*))dlsym(
+          RTLD_DEFAULT, "gdk_wayland_window_remove_frame_callback_surface");
+
+  if (!sGdkWaylandWindowRemoveCallbackSurface) {
+    return;
+  }
+
+  GdkWindow* window = gtk_widget_get_window(GTK_WIDGET(container));
+  MozContainerWayland* wl_container = &container->data.wl_container;
+
+  if (wl_container->surface) {
+    sGdkWaylandWindowRemoveCallbackSurface(window, wl_container->surface);
+  }
+
+  GdkFrameClock* frame_clock = gdk_window_get_frame_clock(window);
+  g_signal_handlers_disconnect_by_func(
+      frame_clock, FuncToGpointer(after_frame_clock_after_paint), container);
+}
+
+void moz_container_wayland_unmap(GtkWidget* widget) {
+  g_return_if_fail(IS_MOZ_CONTAINER(widget));
+
+  // Unmap MozContainer first so we can remove our resources
+  moz_container_unmap(widget);
+
+  MozContainer* container = MOZ_CONTAINER(widget);
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  MutexAutoLock lock(wl_container->container_lock);
+
+  LOGCONTAINER("%s [%p]\n", __FUNCTION__,
+               (void*)moz_container_get_nsWindow(container));
+
+  moz_container_wayland_clear_initial_draw_callback_locked(lock, container);
+
+  if (wl_container->opaque_region_used) {
+    moz_gdk_wayland_window_remove_frame_callback_surface_locked(lock,
+                                                                container);
+  }
+  if (wl_container->commit_to_parent) {
+    wl_container->surface = nullptr;
+  }
+
+  MozClearPointer(wl_container->eglwindow, wl_egl_window_destroy);
+  MozClearPointer(wl_container->subsurface, wl_subsurface_destroy);
+  MozClearPointer(wl_container->surface, wl_surface_destroy);
+  MozClearPointer(wl_container->viewport, wp_viewport_destroy);
+  MozClearPointer(wl_container->fractional_scale,
+                  wp_fractional_scale_v1_destroy);
+
+  wl_container->ready_to_draw = false;
+  wl_container->buffer_scale = 1;
+  wl_container->current_fractional_scale = 0.0;
+}
+
+gboolean moz_container_wayland_map_event(GtkWidget* widget,
+                                         GdkEventAny* event) {
+  MozContainerWayland* wl_container = &MOZ_CONTAINER(widget)->data.wl_container;
+
+  LOGCONTAINER("%s [%p]\n", __FUNCTION__,
+               (void*)moz_container_get_nsWindow(MOZ_CONTAINER(widget)));
+
+  // Return early if we're not mapped. Gtk may send bogus map_event signal
+  // to unmapped widgets (see Bug 1875369).
+  if (!gtk_widget_get_mapped(widget)) {
+    return false;
+  }
+
+  // Make sure we're on main thread as we can't lock mozContainer here
+  // due to moz_container_wayland_add_or_fire_initial_draw_callback() call
+  // below.
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+
+  // Set waiting_to_show flag. It means the mozcontainer is cofigured/mapped
+  // and it's supposed to be visible. *But* it's really visible when we get
+  // moz_container_wayland_add_or_fire_initial_draw_callback() which means
+  // wayland compositor makes it live.
+  wl_container->waiting_to_show = true;
+  MozContainer* container = MOZ_CONTAINER(widget);
+  moz_container_wayland_add_or_fire_initial_draw_callback(
+      container, [container]() -> void {
+        LOGCONTAINER(
+            "[%p] moz_container_wayland_add_or_fire_initial_draw_callback set "
+            "visible",
+            moz_container_get_nsWindow(container));
+        moz_container_wayland_clear_waiting_to_show_flag(container);
+      });
+
+  MutexAutoLock lock(wl_container->container_lock);
+
+  // Don't create wl_subsurface in map_event when it's already created or
+  // if we create it for the first time.
+  if (wl_container->ready_to_draw || wl_container->before_first_size_alloc) {
+    return FALSE;
+  }
+
+  if (!wl_container->surface) {
+    if (!moz_container_wayland_surface_create_locked(lock,
+                                                     MOZ_CONTAINER(widget))) {
+      return FALSE;
+    }
+  }
+
+  nsWindow* window = moz_container_get_nsWindow(MOZ_CONTAINER(widget));
+  moz_container_wayland_set_scale_factor_locked(lock, MOZ_CONTAINER(widget),
+                                                window->GdkCeiledScaleFactor());
+  moz_container_wayland_set_opaque_region_locked(lock, MOZ_CONTAINER(widget));
+  moz_container_clear_input_region(MOZ_CONTAINER(widget));
+  moz_container_wayland_invalidate(MOZ_CONTAINER(widget));
+  return FALSE;
+}
+
+void moz_container_wayland_map(GtkWidget* widget) {
+  LOGCONTAINER("%s [%p]\n", __FUNCTION__,
+               (void*)moz_container_get_nsWindow(MOZ_CONTAINER(widget)));
+
+  g_return_if_fail(IS_MOZ_CONTAINER(widget));
+
+  // We need to mark MozContainer as mapped to make sure
+  // moz_container_wayland_unmap() is called on hide/withdraw.
+  gtk_widget_set_mapped(widget, TRUE);
+
+  if (gtk_widget_get_has_window(widget)) {
+    gdk_window_show(gtk_widget_get_window(widget));
+  }
+}
+
+void moz_container_wayland_size_allocate(GtkWidget* widget,
+                                         GtkAllocation* allocation) {
+  MozContainer* container;
+  GtkAllocation tmp_allocation;
+
+  g_return_if_fail(IS_MOZ_CONTAINER(widget));
+
+  LOGCONTAINER("moz_container_wayland_size_allocate [%p] %d,%d -> %d x %d\n",
+               (void*)moz_container_get_nsWindow(MOZ_CONTAINER(widget)),
+               allocation->x, allocation->y, allocation->width,
+               allocation->height);
+
+  /* short circuit if you can */
+  container = MOZ_CONTAINER(widget);
+  gtk_widget_get_allocation(widget, &tmp_allocation);
+  if (!container->data.children && tmp_allocation.x == allocation->x &&
+      tmp_allocation.y == allocation->y &&
+      tmp_allocation.width == allocation->width &&
+      tmp_allocation.height == allocation->height) {
+    return;
+  }
+  gtk_widget_set_allocation(widget, allocation);
+
+  if (gtk_widget_get_has_window(widget) && gtk_widget_get_realized(widget)) {
+    gdk_window_move_resize(gtk_widget_get_window(widget), allocation->x,
+                           allocation->y, allocation->width,
+                           allocation->height);
+    // We need to position our subsurface according to GdkWindow
+    // when offset changes (GdkWindow is maximized for instance).
+    // see gtk-clutter-embed.c for reference.
+    MutexAutoLock lock(container->data.wl_container.container_lock);
+    if (!container->data.wl_container.surface) {
+      if (!moz_container_wayland_surface_create_locked(lock, container)) {
+        return;
+      }
+    }
+    nsWindow* window = moz_container_get_nsWindow(container);
+    moz_container_wayland_set_scale_factor_locked(
+        lock, container, window->GdkCeiledScaleFactor());
+    moz_container_wayland_set_opaque_region_locked(lock, container);
+    moz_container_wayland_move_locked(lock, container, allocation->x,
+                                      allocation->y);
+    moz_container_clear_input_region(container);
+    moz_container_wayland_invalidate(MOZ_CONTAINER(widget));
+    container->data.wl_container.before_first_size_alloc = false;
+  }
+}
+
+static wl_region* moz_container_wayland_create_opaque_region(
+    int aX, int aY, int aWidth, int aHeight, int aCornerRadius) {
+  struct wl_compositor* compositor = WaylandDisplayGet()->GetCompositor();
+  wl_region* region = wl_compositor_create_region(compositor);
+  wl_region_add(region, aX, aY, aWidth, aHeight);
+  if (aCornerRadius) {
+    wl_region_subtract(region, aX, aY, aCornerRadius, aCornerRadius);
+    wl_region_subtract(region, aX + aWidth - aCornerRadius, aY, aCornerRadius,
+                       aCornerRadius);
+    wl_region_subtract(region, aX, aY + aHeight - aCornerRadius, aCornerRadius,
+                       aCornerRadius);
+    wl_region_subtract(region, aX + aWidth - aCornerRadius,
+                       aY + aHeight - aCornerRadius, aCornerRadius,
+                       aCornerRadius);
+  }
+  return region;
+}
+
+static void moz_container_wayland_set_opaque_region_locked(
+    const MutexAutoLock& aProofOfLock, MozContainer* container) {
+  MozContainerWayland* wl_container = &container->data.wl_container;
+
+  if (!wl_container->opaque_region_needs_updates) {
+    return;
+  }
+
+  if (!wl_container->opaque_region_used) {
+    wl_container->opaque_region_needs_updates = false;
+    return;
+  }
+
+  GtkAllocation allocation;
+  gtk_widget_get_allocation(GTK_WIDGET(container), &allocation);
+
+  wl_region* region = moz_container_wayland_create_opaque_region(
+      0, 0, allocation.width, allocation.height,
+      wl_container->opaque_region_corner_radius);
+  wl_surface_set_opaque_region(wl_container->surface, region);
+  wl_region_destroy(region);
+  wl_container->opaque_region_needs_updates = false;
+}
+
+static void moz_container_wayland_set_opaque_region(MozContainer* container) {
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  MutexAutoLock lock(wl_container->container_lock);
+  if (wl_container->surface) {
+    moz_container_wayland_set_opaque_region_locked(lock, container);
+  }
+}
+
+static void moz_container_wayland_surface_set_scale_locked(
+    const MutexAutoLock& aProofOfLock, MozContainerWayland* wl_container,
+    int scale) {
+  if (!wl_container->surface) {
+    return;
+  }
+  if (wl_container->buffer_scale == scale) {
+    return;
+  }
+
+  LOGCONTAINER("%s scale %d\n", __FUNCTION__, scale);
+
+  // There is a chance that the attached wl_buffer has not yet been doubled
+  // on the main thread when scale factor changed to 2. This leads to
+  // crash with the following message:
+  // Buffer size (AxB) must be an integer multiple of the buffer_scale (2)
+  // Removing the possibly wrong wl_buffer to prevent that crash:
+  wl_surface_attach(wl_container->surface, nullptr, 0, 0);
+  wl_surface_set_buffer_scale(wl_container->surface, scale);
+  wl_container->buffer_scale = scale;
+}
+
+static void fractional_scale_handle_preferred_scale(
+    void* data, struct wp_fractional_scale_v1* info, uint32_t wire_scale) {
+  MozContainer* container = MOZ_CONTAINER(data);
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  wl_container->current_fractional_scale = wire_scale / 120.0;
+
+  RefPtr<nsWindow> window = moz_container_get_nsWindow(container);
+  LOGWAYLAND("%s [%p] scale: %f\n", __func__, window.get(),
+             wl_container->current_fractional_scale);
+  MOZ_DIAGNOSTIC_ASSERT(window);
+  window->OnScaleChanged(/* aNotify = */ true);
+}
+
+static const struct wp_fractional_scale_v1_listener fractional_scale_listener =
+    {
+        .preferred_scale = fractional_scale_handle_preferred_scale,
+};
+
+void moz_container_wayland_set_scale_factor_locked(
+    const MutexAutoLock& aProofOfLock, MozContainer* container, int aScale) {
+  if (gfx::gfxVars::UseWebRenderCompositor()) {
+    // the compositor backend handles scaling itself
+    return;
+  }
+
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  wl_container->container_lock.AssertCurrentThreadOwns();
+
+  if (StaticPrefs::widget_wayland_fractional_scale_enabled_AtStartup()) {
+    if (!wl_container->fractional_scale) {
+      if (auto* manager = WaylandDisplayGet()->GetFractionalScaleManager()) {
+        wl_container->fractional_scale =
+            wp_fractional_scale_manager_v1_get_fractional_scale(
+                manager, wl_container->surface);
+        wp_fractional_scale_v1_add_listener(wl_container->fractional_scale,
+                                            &fractional_scale_listener,
+                                            container);
+      }
+    }
+
+    if (wl_container->fractional_scale) {
+      if (!wl_container->viewport) {
+        if (auto* viewporter = WaylandDisplayGet()->GetViewporter()) {
+          wl_container->viewport =
+              wp_viewporter_get_viewport(viewporter, wl_container->surface);
+        }
+      }
+      if (wl_container->viewport) {
+        GdkWindow* gdkWindow = gtk_widget_get_window(GTK_WIDGET(container));
+        wp_viewport_set_destination(wl_container->viewport,
+                                    gdk_window_get_width(gdkWindow),
+                                    gdk_window_get_height(gdkWindow));
+        return;
+      }
+    }
+  }
+
+  moz_container_wayland_surface_set_scale_locked(aProofOfLock, wl_container,
+                                                 aScale);
+}
+
+bool moz_container_wayland_size_matches_scale_factor_locked(
+    const MutexAutoLock& aProofOfLock, MozContainer* container, int aWidth,
+    int aHeight) {
+  return aWidth % container->data.wl_container.buffer_scale == 0 &&
+         aHeight % container->data.wl_container.buffer_scale == 0;
+}
+
+static bool moz_container_wayland_surface_create_locked(
+    const MutexAutoLock& aProofOfLock, MozContainer* container) {
+  MozContainerWayland* wl_container = &container->data.wl_container;
+
+  LOGWAYLAND("%s [%p]\n", __FUNCTION__,
+             (void*)moz_container_get_nsWindow(container));
+
+  GdkWindow* window = gtk_widget_get_window(GTK_WIDGET(container));
+  MOZ_DIAGNOSTIC_ASSERT(window);
+
+  wl_surface* parent_surface = gdk_wayland_window_get_wl_surface(window);
+  if (!parent_surface) {
+    LOGWAYLAND("    Failed - missing parent surface!");
+    return false;
+  }
+  LOGWAYLAND("    gtk wl_surface %p ID %d\n", (void*)parent_surface,
+             wl_proxy_get_id((struct wl_proxy*)parent_surface));
+
+  if (wl_container->commit_to_parent) {
+    LOGWAYLAND("    commit to parent");
+    wl_container->surface = parent_surface;
+    NS_DispatchToCurrentThread(NewRunnableFunction(
+        "moz_container_wayland_frame_callback_handler",
+        &moz_container_wayland_frame_callback_handler, container, nullptr, 0));
+    return true;
+  }
+
+  // Available as of GTK 3.8+
+  struct wl_compositor* compositor = WaylandDisplayGet()->GetCompositor();
+  wl_container->surface = wl_compositor_create_surface(compositor);
+  if (!wl_container->surface) {
+    LOGWAYLAND("    Failed - can't create surface!");
+    return false;
+  }
+
+  wl_container->subsurface =
+      wl_subcompositor_get_subsurface(WaylandDisplayGet()->GetSubcompositor(),
+                                      wl_container->surface, parent_surface);
+  if (!wl_container->subsurface) {
+    MozClearPointer(wl_container->surface, wl_surface_destroy);
+    LOGWAYLAND("    Failed - can't create sub-surface!");
+    return false;
+  }
+  wl_subsurface_set_desync(wl_container->subsurface);
+
+  // Try to guess subsurface offset to avoid potential flickering.
+  int dx, dy;
+  if (moz_container_get_nsWindow(container)->GetCSDDecorationOffset(&dx, &dy)) {
+    wl_container->subsurface_dx = dx;
+    wl_container->subsurface_dy = dy;
+    wl_subsurface_set_position(wl_container->subsurface, dx, dy);
+    LOGWAYLAND("    guessing subsurface position %d %d\n", dx, dy);
+  }
+
+  // If there's pending frame callback it's for wrong parent surface,
+  // so delete it.
+  if (wl_container->frame_callback_handler) {
+    MozClearPointer(wl_container->frame_callback_handler, wl_callback_destroy);
+  }
+  wl_container->frame_callback_handler = wl_surface_frame(parent_surface);
+  wl_callback_add_listener(wl_container->frame_callback_handler,
+                           &moz_container_frame_listener, container);
+  LOGWAYLAND(
+      "    created frame callback ID %d\n",
+      wl_proxy_get_id((struct wl_proxy*)wl_container->frame_callback_handler));
+
+  wl_surface_commit(wl_container->surface);
+  wl_display_flush(WaylandDisplayGet()->GetDisplay());
+
+  wl_container->opaque_region_used =
+      moz_gdk_wayland_window_add_frame_callback_surface_locked(aProofOfLock,
+                                                               container);
+
+  LOGWAYLAND("    created surface %p ID %d\n", (void*)wl_container->surface,
+             wl_proxy_get_id((struct wl_proxy*)wl_container->surface));
+  return true;
+}
+
+struct wl_surface* moz_container_wayland_surface_lock(MozContainer* container)
+    MOZ_NO_THREAD_SAFETY_ANALYSIS {
+  // LOGWAYLAND("%s [%p] surface %p ready_to_draw %d\n", __FUNCTION__,
+  //           (void*)container, (void*)container->data.wl_container.surface,
+  //           container->data.wl_container.ready_to_draw);
+  container->data.wl_container.container_lock.Lock();
+  if (!container->data.wl_container.surface ||
+      !container->data.wl_container.ready_to_draw) {
+    return nullptr;
+  }
+  return container->data.wl_container.surface;
+}
+
+void moz_container_wayland_surface_unlock(MozContainer* container,
+                                          struct wl_surface** surface)
+    MOZ_NO_THREAD_SAFETY_ANALYSIS {
+  // Temporarily disabled to avoid log noise
+  // LOGWAYLAND("%s [%p] surface %p\n", __FUNCTION__, (void*)container,
+  //            (void*)container->data.wl_container.surface);
+  if (*surface) {
+    *surface = nullptr;
+  }
+  container->data.wl_container.container_lock.Unlock();
+}
+
+struct wl_egl_window* moz_container_wayland_get_egl_window(
+    MozContainer* container, double scale) {
+  MozContainerWayland* wl_container = &container->data.wl_container;
+
+  LOGCONTAINER("%s [%p] eglwindow %p scale %d\n", __FUNCTION__,
+               (void*)moz_container_get_nsWindow(container),
+               (void*)wl_container->eglwindow, (int)scale);
+
+  MutexAutoLock lock(wl_container->container_lock);
+  if (!wl_container->surface || !wl_container->ready_to_draw) {
+    LOGCONTAINER(
+        "  quit, wl_container->surface %p wl_container->ready_to_draw %d\n",
+        wl_container->surface, wl_container->ready_to_draw);
+    return nullptr;
+  }
+
+  GdkWindow* window = gtk_widget_get_window(GTK_WIDGET(container));
+  nsIntSize requestedSize((int)round(gdk_window_get_width(window) * scale),
+                          (int)round(gdk_window_get_height(window) * scale));
+
+  if (!wl_container->eglwindow) {
+    wl_container->eglwindow = wl_egl_window_create(
+        wl_container->surface, requestedSize.width, requestedSize.height);
+
+    LOGCONTAINER("%s [%p] created eglwindow %p size %d x %d (with scale %f)\n",
+                 __FUNCTION__, (void*)moz_container_get_nsWindow(container),
+                 (void*)wl_container->eglwindow, requestedSize.width,
+                 requestedSize.height, scale);
+  } else {
+    nsIntSize recentSize;
+    wl_egl_window_get_attached_size(wl_container->eglwindow, &recentSize.width,
+                                    &recentSize.height);
+    if (requestedSize != recentSize) {
+      LOGCONTAINER("%s [%p] resized to %d x %d (with scale %f)\n", __FUNCTION__,
+                   (void*)moz_container_get_nsWindow(container),
+                   requestedSize.width, requestedSize.height, scale);
+      wl_egl_window_resize(wl_container->eglwindow, requestedSize.width,
+                           requestedSize.height, 0, 0);
+    }
+  }
+  moz_container_wayland_surface_set_scale_locked(lock, wl_container,
+                                                 static_cast<int>(scale));
+  return wl_container->eglwindow;
+}
+
+gboolean moz_container_wayland_has_egl_window(MozContainer* container) {
+  return !!container->data.wl_container.eglwindow;
+}
+
+void moz_container_wayland_update_opaque_region(MozContainer* container,
+                                                int corner_radius) {
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  wl_container->opaque_region_needs_updates = true;
+  wl_container->opaque_region_corner_radius = corner_radius;
+
+  // When GL compositor / WebRender is used,
+  // moz_container_wayland_get_egl_window() is called only once when window
+  // is created or resized so update opaque region now.
+  if (moz_container_wayland_has_egl_window(container)) {
+    moz_container_wayland_set_opaque_region(container);
+  }
+}
+
+gboolean moz_container_wayland_can_draw(MozContainer* container) {
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  MutexAutoLock lock(wl_container->container_lock);
+  return wl_container->ready_to_draw;
+}
+
+double moz_container_wayland_get_fractional_scale(MozContainer* container) {
+  return container->data.wl_container.current_fractional_scale;
+}
+
+double moz_container_wayland_get_scale(MozContainer* container) {
+  nsWindow* window = moz_container_get_nsWindow(container);
+  return window ? window->FractionalScaleFactor() : 1.0;
+}
+
+void moz_container_wayland_set_commit_to_parent(MozContainer* container) {
+  MozContainerWayland* wl_container = &container->data.wl_container;
+  MOZ_DIAGNOSTIC_ASSERT(!wl_container->surface);
+  wl_container->commit_to_parent = true;
+}
+
+bool moz_container_wayland_is_commiting_to_parent(MozContainer* container) {
+  return container->data.wl_container.commit_to_parent;
+}
+
+bool moz_container_wayland_is_waiting_to_show(MozContainer* container) {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  return container->data.wl_container.waiting_to_show;
+}
+
+void moz_container_wayland_clear_waiting_to_show_flag(MozContainer* container) {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  container->data.wl_container.waiting_to_show = false;
+}
diff --git a/widget/gtk/MozContainerWayland.h b/widget/gtk/MozContainerWayland.h
new file mode 100644
index 0000000000..068c674256
--- /dev/null
+++ b/widget/gtk/MozContainerWayland.h
@@ -0,0 +1,110 @@
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __MOZ_CONTAINER_WAYLAND_H__
+#define __MOZ_CONTAINER_WAYLAND_H__
+
+#include <gtk/gtk.h>
+#include <functional>
+#include <vector>
+#include "mozilla/Mutex.h"
+#include "WindowSurface.h"
+
+/*
+ * MozContainer
+ *
+ * This class serves three purposes in the nsIWidget implementation.
+ *
+ *   - It provides objects to receive signals from GTK for events on native
+ *     windows.
+ *
+ *   - It provides GdkWindow to draw content on Wayland or when Gtk+ renders
+ *     client side decorations to mShell.
+ */
+
+/* Workaround for bug at wayland-util.h,
+ * present in wayland-devel < 1.12
+ */
+struct wl_surface;
+struct wl_subsurface;
+
+struct MozContainerWayland {
+  struct wl_surface* surface = nullptr;
+  struct wl_subsurface* subsurface = nullptr;
+  int subsurface_dx = 0;
+  int subsurface_dy = 0;
+  struct wl_egl_window* eglwindow = nullptr;
+  struct wl_callback* frame_callback_handler = nullptr;
+  struct wp_viewport* viewport = nullptr;
+  struct wp_fractional_scale_v1* fractional_scale = nullptr;
+  gboolean opaque_region_needs_updates = false;
+  int opaque_region_corner_radius = 0;
+  gboolean opaque_region_used = false;
+  gboolean ready_to_draw = false;
+  gboolean commit_to_parent = false;
+  gboolean before_first_size_alloc = false;
+  gboolean waiting_to_show = false;
+  // Zero means no fractional scale set.
+  double current_fractional_scale = 0.0;
+  int buffer_scale = 1;
+  std::vector<std::function<void(void)>> initial_draw_cbs;
+  // mozcontainer is used from Compositor and Rendering threads so we need to
+  // control access to mozcontainer where wayland internals are used directly.
+  mozilla::Mutex container_lock{"MozContainerWayland::container_lock"};
+};
+
+struct _MozContainer;
+struct _MozContainerClass;
+typedef struct _MozContainer MozContainer;
+typedef struct _MozContainerClass MozContainerClass;
+
+class MozContainerSurfaceLock {
+  MozContainer* mContainer;
+  struct wl_surface* mSurface;
+
+ public:
+  explicit MozContainerSurfaceLock(MozContainer* aContainer);
+  ~MozContainerSurfaceLock();
+  struct wl_surface* GetSurface();
+};
+
+void moz_container_wayland_map(GtkWidget*);
+gboolean moz_container_wayland_map_event(GtkWidget*, GdkEventAny*);
+void moz_container_wayland_size_allocate(GtkWidget*, GtkAllocation*);
+void moz_container_wayland_unmap(GtkWidget*);
+
+struct wl_egl_window* moz_container_wayland_get_egl_window(
+    MozContainer* container, double scale);
+
+gboolean moz_container_wayland_has_egl_window(MozContainer* container);
+bool moz_container_wayland_egl_window_set_size(MozContainer* container,
+                                               nsIntSize aSize, int aScale);
+void moz_container_wayland_set_scale_factor_locked(
+    const mozilla::MutexAutoLock& aProofOfLock, MozContainer* container,
+    int aScale);
+bool moz_container_wayland_size_matches_scale_factor_locked(
+    const mozilla::MutexAutoLock& aProofOfLock, MozContainer* container,
+    int aWidth, int aHeight);
+
+void moz_container_wayland_add_initial_draw_callback_locked(
+    MozContainer* container, const std::function<void(void)>& initial_draw_cb);
+void moz_container_wayland_add_or_fire_initial_draw_callback(
+    MozContainer* container, const std::function<void(void)>& initial_draw_cb);
+void moz_container_wayland_clear_initial_draw_callback(MozContainer* container);
+
+wl_surface* moz_gtk_widget_get_wl_surface(GtkWidget* aWidget);
+void moz_container_wayland_update_opaque_region(MozContainer* container,
+                                                int corner_radius);
+gboolean moz_container_wayland_can_draw(MozContainer* container);
+double moz_container_wayland_get_scale(MozContainer* container);
+double moz_container_wayland_get_fractional_scale(MozContainer* container);
+void moz_container_wayland_set_commit_to_parent(MozContainer* container);
+bool moz_container_wayland_is_commiting_to_parent(MozContainer* container);
+bool moz_container_wayland_is_waiting_to_show(MozContainer* container);
+void moz_container_wayland_clear_waiting_to_show_flag(MozContainer* container);
+
+#endif /* __MOZ_CONTAINER_WAYLAND_H__ */
diff --git a/widget/gtk/NativeKeyBindings.cpp b/widget/gtk/NativeKeyBindings.cpp
new file mode 100644
index 0000000000..e050fd07c0
--- /dev/null
+++ b/widget/gtk/NativeKeyBindings.cpp
@@ -0,0 +1,527 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/MathAlgorithms.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/StaticPrefs_ui.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/WritingModes.h"
+
+#include "NativeKeyBindings.h"
+#include "nsString.h"
+#include "nsGtkKeyUtils.h"
+
+#include <gtk/gtk.h>
+#include <gdk/gdkkeysyms.h>
+#include <gdk/gdkkeysyms-compat.h>
+#include <gdk/gdk.h>
+
+namespace mozilla {
+namespace widget {
+
+static nsTArray<CommandInt>* gCurrentCommands = nullptr;
+static bool gHandled = false;
+
+inline void AddCommand(Command aCommand) {
+  MOZ_ASSERT(gCurrentCommands);
+  gCurrentCommands->AppendElement(static_cast<CommandInt>(aCommand));
+}
+
+// Common GtkEntry and GtkTextView signals
+static void copy_clipboard_cb(GtkWidget* w, gpointer user_data) {
+  AddCommand(Command::Copy);
+  g_signal_stop_emission_by_name(w, "copy_clipboard");
+  gHandled = true;
+}
+
+static void cut_clipboard_cb(GtkWidget* w, gpointer user_data) {
+  AddCommand(Command::Cut);
+  g_signal_stop_emission_by_name(w, "cut_clipboard");
+  gHandled = true;
+}
+
+// GTK distinguishes between display lines (wrapped, as they appear on the
+// screen) and paragraphs, which are runs of text terminated by a newline.
+// We don't have this distinction, so we always use editor's notion of
+// lines, which are newline-terminated.
+
+static const Command sDeleteCommands[][2] = {
+    // backward, forward
+    // CHARS
+    {Command::DeleteCharBackward, Command::DeleteCharForward},
+    // WORD_ENDS
+    {Command::DeleteWordBackward, Command::DeleteWordForward},
+    // WORDS
+    {Command::DeleteWordBackward, Command::DeleteWordForward},
+    // LINES
+    {Command::DeleteToBeginningOfLine, Command::DeleteToEndOfLine},
+    // LINE_ENDS
+    {Command::DeleteToBeginningOfLine, Command::DeleteToEndOfLine},
+    // PARAGRAPH_ENDS
+    {Command::DeleteToBeginningOfLine, Command::DeleteToEndOfLine},
+    // PARAGRAPHS
+    {Command::DeleteToBeginningOfLine, Command::DeleteToEndOfLine},
+    // This deletes from the end of the previous word to the beginning of the
+    // next word, but only if the caret is not in a word.
+    // XXX need to implement in editor
+    {Command::DoNothing, Command::DoNothing}  // WHITESPACE
+};
+
+static void delete_from_cursor_cb(GtkWidget* w, GtkDeleteType del_type,
+                                  gint count, gpointer user_data) {
+  g_signal_stop_emission_by_name(w, "delete_from_cursor");
+  if (count == 0) {
+    // Nothing to do.
+    return;
+  }
+
+  bool forward = count > 0;
+
+  // Ignore GTK's Ctrl-K keybinding introduced in GTK 3.14 and removed in
+  // 3.18 if the user has custom bindings set. See bug 1176929.
+  if (del_type == GTK_DELETE_PARAGRAPH_ENDS && forward && GTK_IS_ENTRY(w) &&
+      !gtk_check_version(3, 14, 1) && gtk_check_version(3, 17, 9)) {
+    GtkStyleContext* context = gtk_widget_get_style_context(w);
+    GtkStateFlags flags = gtk_widget_get_state_flags(w);
+
+    GPtrArray* array;
+    gtk_style_context_get(context, flags, "gtk-key-bindings", &array, nullptr);
+    if (!array) return;
+    g_ptr_array_unref(array);
+  }
+
+  gHandled = true;
+  if (uint32_t(del_type) >= ArrayLength(sDeleteCommands)) {
+    // unsupported deletion type
+    return;
+  }
+
+  if (del_type == GTK_DELETE_WORDS) {
+    // This works like word_ends, except we first move the caret to the
+    // beginning/end of the current word.
+    if (forward) {
+      AddCommand(Command::WordNext);
+      AddCommand(Command::WordPrevious);
+    } else {
+      AddCommand(Command::WordPrevious);
+      AddCommand(Command::WordNext);
+    }
+  } else if (del_type == GTK_DELETE_DISPLAY_LINES ||
+             del_type == GTK_DELETE_PARAGRAPHS) {
+    // This works like display_line_ends, except we first move the caret to the
+    // beginning/end of the current line.
+    if (forward) {
+      AddCommand(Command::BeginLine);
+    } else {
+      AddCommand(Command::EndLine);
+    }
+  }
+
+  Command command = sDeleteCommands[del_type][forward];
+  if (command == Command::DoNothing) {
+    return;
+  }
+
+  unsigned int absCount = Abs(count);
+  for (unsigned int i = 0; i < absCount; ++i) {
+    AddCommand(command);
+  }
+}
+
+static const Command sMoveCommands[][2][2] = {
+    // non-extend { backward, forward }, extend { backward, forward }
+    // GTK differentiates between logical position, which is prev/next,
+    // and visual position, which is always left/right.
+    // We should fix this to work the same way for RTL text input.
+    {// LOGICAL_POSITIONS
+     {Command::CharPrevious, Command::CharNext},
+     {Command::SelectCharPrevious, Command::SelectCharNext}},
+    {// VISUAL_POSITIONS
+     {Command::CharPrevious, Command::CharNext},
+     {Command::SelectCharPrevious, Command::SelectCharNext}},
+    {// WORDS
+     {Command::WordPrevious, Command::WordNext},
+     {Command::SelectWordPrevious, Command::SelectWordNext}},
+    {// DISPLAY_LINES
+     {Command::LinePrevious, Command::LineNext},
+     {Command::SelectLinePrevious, Command::SelectLineNext}},
+    {// DISPLAY_LINE_ENDS
+     {Command::BeginLine, Command::EndLine},
+     {Command::SelectBeginLine, Command::SelectEndLine}},
+    {// PARAGRAPHS
+     {Command::LinePrevious, Command::LineNext},
+     {Command::SelectLinePrevious, Command::SelectLineNext}},
+    {// PARAGRAPH_ENDS
+     {Command::BeginLine, Command::EndLine},
+     {Command::SelectBeginLine, Command::SelectEndLine}},
+    {// PAGES
+     {Command::MovePageUp, Command::MovePageDown},
+     {Command::SelectPageUp, Command::SelectPageDown}},
+    {// BUFFER_ENDS
+     {Command::MoveTop, Command::MoveBottom},
+     {Command::SelectTop, Command::SelectBottom}},
+    {// HORIZONTAL_PAGES (unsupported)
+     {Command::DoNothing, Command::DoNothing},
+     {Command::DoNothing, Command::DoNothing}}};
+
+static void move_cursor_cb(GtkWidget* w, GtkMovementStep step, gint count,
+                           gboolean extend_selection, gpointer user_data) {
+  g_signal_stop_emission_by_name(w, "move_cursor");
+  if (count == 0) {
+    // Nothing to do.
+    return;
+  }
+
+  gHandled = true;
+  bool forward = count > 0;
+  if (uint32_t(step) >= ArrayLength(sMoveCommands)) {
+    // unsupported movement type
+    return;
+  }
+
+  Command command = sMoveCommands[step][extend_selection][forward];
+  if (command == Command::DoNothing) {
+    return;
+  }
+
+  unsigned int absCount = Abs(count);
+  for (unsigned int i = 0; i < absCount; ++i) {
+    AddCommand(command);
+  }
+}
+
+static void paste_clipboard_cb(GtkWidget* w, gpointer user_data) {
+  AddCommand(Command::Paste);
+  g_signal_stop_emission_by_name(w, "paste_clipboard");
+  gHandled = true;
+}
+
+// GtkTextView-only signals
+static void select_all_cb(GtkWidget* aWidget, gboolean aSelect,
+                          gpointer aUserData) {
+  // We don't support "Unselect All" command.
+  // Note that if we'd support it, `Ctrl-Shift-a` will be mapped to it and
+  // overrides open `about:addons` shortcut.
+  if (aSelect) {
+    AddCommand(Command::SelectAll);
+  }
+  g_signal_stop_emission_by_name(aWidget, "select_all");
+  // Although we prevent the default of `GtkTExtView` with
+  // `g_signal_stop_emission_by_name`, but `gHandled` is used for asserting
+  // if it does not match with the emptiness of the command array.
+  // Therefore, we should not set it to `true` if we don't add a command.
+  gHandled |= aSelect;
+}
+
+NativeKeyBindings* NativeKeyBindings::sInstanceForSingleLineEditor = nullptr;
+NativeKeyBindings* NativeKeyBindings::sInstanceForMultiLineEditor = nullptr;
+
+// static
+NativeKeyBindings* NativeKeyBindings::GetInstance(NativeKeyBindingsType aType) {
+  switch (aType) {
+    case NativeKeyBindingsType::SingleLineEditor:
+      if (!sInstanceForSingleLineEditor) {
+        sInstanceForSingleLineEditor = new NativeKeyBindings();
+        sInstanceForSingleLineEditor->Init(aType);
+      }
+      return sInstanceForSingleLineEditor;
+
+    default:
+      // fallback to multiline editor case in release build
+      MOZ_FALLTHROUGH_ASSERT("aType is invalid or not yet implemented");
+    case NativeKeyBindingsType::MultiLineEditor:
+    case NativeKeyBindingsType::RichTextEditor:
+      if (!sInstanceForMultiLineEditor) {
+        sInstanceForMultiLineEditor = new NativeKeyBindings();
+        sInstanceForMultiLineEditor->Init(aType);
+      }
+      return sInstanceForMultiLineEditor;
+  }
+}
+
+// static
+void NativeKeyBindings::Shutdown() {
+  delete sInstanceForSingleLineEditor;
+  sInstanceForSingleLineEditor = nullptr;
+  delete sInstanceForMultiLineEditor;
+  sInstanceForMultiLineEditor = nullptr;
+}
+
+void NativeKeyBindings::Init(NativeKeyBindingsType aType) {
+  switch (aType) {
+    case NativeKeyBindingsType::SingleLineEditor:
+      mNativeTarget = gtk_entry_new();
+      break;
+    default:
+      mNativeTarget = gtk_text_view_new();
+      g_signal_connect(mNativeTarget, "select_all", G_CALLBACK(select_all_cb),
+                       this);
+      break;
+  }
+
+  g_object_ref_sink(mNativeTarget);
+
+  g_signal_connect(mNativeTarget, "copy_clipboard",
+                   G_CALLBACK(copy_clipboard_cb), this);
+  g_signal_connect(mNativeTarget, "cut_clipboard", G_CALLBACK(cut_clipboard_cb),
+                   this);
+  g_signal_connect(mNativeTarget, "delete_from_cursor",
+                   G_CALLBACK(delete_from_cursor_cb), this);
+  g_signal_connect(mNativeTarget, "move_cursor", G_CALLBACK(move_cursor_cb),
+                   this);
+  g_signal_connect(mNativeTarget, "paste_clipboard",
+                   G_CALLBACK(paste_clipboard_cb), this);
+}
+
+NativeKeyBindings::~NativeKeyBindings() {
+  gtk_widget_destroy(mNativeTarget);
+  g_object_unref(mNativeTarget);
+}
+
+void NativeKeyBindings::GetEditCommands(const WidgetKeyboardEvent& aEvent,
+                                        const Maybe<WritingMode>& aWritingMode,
+                                        nsTArray<CommandInt>& aCommands) {
+  MOZ_ASSERT(!aEvent.mFlags.mIsSynthesizedForTests);
+  MOZ_ASSERT(aCommands.IsEmpty());
+
+  // It must be a DOM event dispached by chrome script.
+  if (!aEvent.mNativeKeyEvent) {
+    return;
+  }
+
+  guint keyval;
+  if (aEvent.mCharCode) {
+    keyval = gdk_unicode_to_keyval(aEvent.mCharCode);
+  } else if (aWritingMode.isSome() && aEvent.NeedsToRemapNavigationKey() &&
+             aWritingMode.ref().IsVertical()) {
+    // TODO: Use KeyNameIndex rather than legacy keyCode.
+    uint32_t remappedGeckoKeyCode =
+        aEvent.GetRemappedKeyCode(aWritingMode.ref());
+    switch (remappedGeckoKeyCode) {
+      case NS_VK_UP:
+        keyval = GDK_Up;
+        break;
+      case NS_VK_DOWN:
+        keyval = GDK_Down;
+        break;
+      case NS_VK_LEFT:
+        keyval = GDK_Left;
+        break;
+      case NS_VK_RIGHT:
+        keyval = GDK_Right;
+        break;
+      default:
+        MOZ_ASSERT_UNREACHABLE("Add a case for the new remapped key");
+        return;
+    }
+  } else {
+    keyval = static_cast<GdkEventKey*>(aEvent.mNativeKeyEvent)->keyval;
+  }
+
+  if (GetEditCommandsInternal(aEvent, aCommands, keyval)) {
+    return;
+  }
+
+  for (uint32_t i = 0; i < aEvent.mAlternativeCharCodes.Length(); ++i) {
+    uint32_t ch = aEvent.IsShift()
+                      ? aEvent.mAlternativeCharCodes[i].mShiftedCharCode
+                      : aEvent.mAlternativeCharCodes[i].mUnshiftedCharCode;
+    if (ch && ch != aEvent.mCharCode) {
+      keyval = gdk_unicode_to_keyval(ch);
+      if (GetEditCommandsInternal(aEvent, aCommands, keyval)) {
+        return;
+      }
+    }
+  }
+
+  // If the key event does not cause any commands, and we're for single line
+  // editor, let's check whether the key combination is for "select-all" in
+  // GtkTextView because the signal is not supported by GtkEntry.
+  if (aCommands.IsEmpty() && this == sInstanceForSingleLineEditor &&
+      StaticPrefs::ui_key_use_select_all_in_single_line_editor()) {
+    if (NativeKeyBindings* bindingsForMultilineEditor =
+            GetInstance(NativeKeyBindingsType::MultiLineEditor)) {
+      bindingsForMultilineEditor->GetEditCommands(aEvent, aWritingMode,
+                                                  aCommands);
+      if (aCommands.Length() == 1u &&
+          aCommands[0u] == static_cast<CommandInt>(Command::SelectAll)) {
+        return;
+      }
+      aCommands.Clear();
+    }
+  }
+
+  /*
+  gtk_bindings_activate_event is preferable, but it has unresolved bug:
+  http://bugzilla.gnome.org/show_bug.cgi?id=162726
+  The bug was already marked as FIXED.  However, somebody reports that the
+  bug still exists.
+  Also gtk_bindings_activate may work with some non-shortcuts operations
+  (todo: check it). See bug 411005 and bug 406407.
+
+  Code, which should be used after fixing GNOME bug 162726:
+
+    gtk_bindings_activate_event(GTK_OBJECT(mNativeTarget),
+      static_cast<GdkEventKey*>(aEvent.mNativeKeyEvent));
+  */
+}
+
+bool NativeKeyBindings::GetEditCommandsInternal(
+    const WidgetKeyboardEvent& aEvent, nsTArray<CommandInt>& aCommands,
+    guint aKeyval) {
+  guint modifiers = static_cast<GdkEventKey*>(aEvent.mNativeKeyEvent)->state;
+
+  gCurrentCommands = &aCommands;
+
+  gHandled = false;
+  gtk_bindings_activate(G_OBJECT(mNativeTarget), aKeyval,
+                        GdkModifierType(modifiers));
+
+  gCurrentCommands = nullptr;
+
+  return gHandled;
+}
+
+// static
+void NativeKeyBindings::GetEditCommandsForTests(
+    NativeKeyBindingsType aType, const WidgetKeyboardEvent& aEvent,
+    const Maybe<WritingMode>& aWritingMode, nsTArray<CommandInt>& aCommands) {
+  MOZ_DIAGNOSTIC_ASSERT(aEvent.IsTrusted());
+
+  if (aEvent.IsAlt() || aEvent.IsMeta()) {
+    return;
+  }
+
+  static const size_t kBackward = 0;
+  static const size_t kForward = 1;
+  const size_t extentSelection = aEvent.IsShift() ? 1 : 0;
+  // https://github.com/GNOME/gtk/blob/1f141c19533f4b3f397c3959ade673ce243b6138/gtk/gtktext.c#L1289
+  // https://github.com/GNOME/gtk/blob/c5dd34344f0c660ceffffb3bf9da43c263db16e1/gtk/gtktextview.c#L1534
+  Command command = Command::DoNothing;
+  const KeyNameIndex remappedKeyNameIndex =
+      aWritingMode.isSome() ? aEvent.GetRemappedKeyNameIndex(aWritingMode.ref())
+                            : aEvent.mKeyNameIndex;
+  switch (remappedKeyNameIndex) {
+    case KEY_NAME_INDEX_USE_STRING:
+      switch (aEvent.PseudoCharCode()) {
+        case 'a':
+        case 'A':
+          if (aEvent.IsControl()) {
+            command = Command::SelectAll;
+          }
+          break;
+        case 'c':
+        case 'C':
+          if (aEvent.IsControl() && !aEvent.IsShift()) {
+            command = Command::Copy;
+          }
+          break;
+        case 'u':
+        case 'U':
+          if (aType == NativeKeyBindingsType::SingleLineEditor &&
+              aEvent.IsControl() && !aEvent.IsShift()) {
+            command = sDeleteCommands[GTK_DELETE_PARAGRAPH_ENDS][kBackward];
+          }
+          break;
+        case 'v':
+        case 'V':
+          if (aEvent.IsControl() && !aEvent.IsShift()) {
+            command = Command::Paste;
+          }
+          break;
+        case 'x':
+        case 'X':
+          if (aEvent.IsControl() && !aEvent.IsShift()) {
+            command = Command::Cut;
+          }
+          break;
+        case '/':
+          if (aEvent.IsControl() && !aEvent.IsShift()) {
+            command = Command::SelectAll;
+          }
+          break;
+        default:
+          break;
+      }
+      break;
+    case KEY_NAME_INDEX_Insert:
+      if (aEvent.IsControl() && !aEvent.IsShift()) {
+        command = Command::Copy;
+      } else if (aEvent.IsShift() && !aEvent.IsControl()) {
+        command = Command::Paste;
+      }
+      break;
+    case KEY_NAME_INDEX_Delete:
+      if (aEvent.IsShift()) {
+        command = Command::Cut;
+        break;
+      }
+      [[fallthrough]];
+    case KEY_NAME_INDEX_Backspace: {
+      const size_t direction =
+          remappedKeyNameIndex == KEY_NAME_INDEX_Delete ? kForward : kBackward;
+      const GtkDeleteType amount =
+          aEvent.IsControl() && aEvent.IsShift()
+              ? GTK_DELETE_PARAGRAPH_ENDS
+              // FYI: Shift key for Backspace is ignored to help mis-typing.
+              : (aEvent.IsControl() ? GTK_DELETE_WORD_ENDS : GTK_DELETE_CHARS);
+      command = sDeleteCommands[amount][direction];
+      break;
+    }
+    case KEY_NAME_INDEX_ArrowLeft:
+    case KEY_NAME_INDEX_ArrowRight: {
+      const size_t direction = remappedKeyNameIndex == KEY_NAME_INDEX_ArrowRight
+                                   ? kForward
+                                   : kBackward;
+      const GtkMovementStep amount = aEvent.IsControl()
+                                         ? GTK_MOVEMENT_WORDS
+                                         : GTK_MOVEMENT_VISUAL_POSITIONS;
+      command = sMoveCommands[amount][extentSelection][direction];
+      break;
+    }
+    case KEY_NAME_INDEX_ArrowUp:
+    case KEY_NAME_INDEX_ArrowDown: {
+      const size_t direction = remappedKeyNameIndex == KEY_NAME_INDEX_ArrowDown
+                                   ? kForward
+                                   : kBackward;
+      const GtkMovementStep amount = aEvent.IsControl()
+                                         ? GTK_MOVEMENT_PARAGRAPHS
+                                         : GTK_MOVEMENT_DISPLAY_LINES;
+      command = sMoveCommands[amount][extentSelection][direction];
+      break;
+    }
+    case KEY_NAME_INDEX_Home:
+    case KEY_NAME_INDEX_End: {
+      const size_t direction =
+          remappedKeyNameIndex == KEY_NAME_INDEX_End ? kForward : kBackward;
+      const GtkMovementStep amount = aEvent.IsControl()
+                                         ? GTK_MOVEMENT_BUFFER_ENDS
+                                         : GTK_MOVEMENT_DISPLAY_LINE_ENDS;
+      command = sMoveCommands[amount][extentSelection][direction];
+      break;
+    }
+    case KEY_NAME_INDEX_PageUp:
+    case KEY_NAME_INDEX_PageDown: {
+      const size_t direction = remappedKeyNameIndex == KEY_NAME_INDEX_PageDown
+                                   ? kForward
+                                   : kBackward;
+      const GtkMovementStep amount = aEvent.IsControl()
+                                         ? GTK_MOVEMENT_HORIZONTAL_PAGES
+                                         : GTK_MOVEMENT_PAGES;
+      command = sMoveCommands[amount][extentSelection][direction];
+      break;
+    }
+    default:
+      break;
+  }
+  if (command != Command::DoNothing) {
+    aCommands.AppendElement(static_cast<CommandInt>(command));
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/gtk/NativeKeyBindings.h b/widget/gtk/NativeKeyBindings.h
new file mode 100644
index 0000000000..1d0c528621
--- /dev/null
+++ b/widget/gtk/NativeKeyBindings.h
@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NativeKeyBindings_h
+#define NativeKeyBindings_h
+
+#include "mozilla/Attributes.h"
+#include "mozilla/EventForwards.h"
+#include "nsIWidget.h"
+
+#include <glib.h>  // for guint
+
+using GtkWidget = struct _GtkWidget;
+
+namespace mozilla {
+enum class NativeKeyBindingsType : uint8_t;
+
+class WritingMode;
+template <typename T>
+class Maybe;
+
+namespace widget {
+
+class NativeKeyBindings final {
+ public:
+  static NativeKeyBindings* GetInstance(NativeKeyBindingsType aType);
+  static void Shutdown();
+
+  /**
+   * GetEditCommandsForTests() returns commands performed in native widget
+   * in typical environment.  I.e., this does NOT refer customized shortcut
+   * key mappings of the environment.
+   */
+  static void GetEditCommandsForTests(NativeKeyBindingsType aType,
+                                      const WidgetKeyboardEvent& aEvent,
+                                      const Maybe<WritingMode>& aWritingMode,
+                                      nsTArray<CommandInt>& aCommands);
+
+  void Init(NativeKeyBindingsType aType);
+
+  void GetEditCommands(const WidgetKeyboardEvent& aEvent,
+                       const Maybe<WritingMode>& aWritingMode,
+                       nsTArray<CommandInt>& aCommands);
+
+ private:
+  ~NativeKeyBindings();
+
+  bool GetEditCommandsInternal(const WidgetKeyboardEvent& aEvent,
+                               nsTArray<CommandInt>& aCommands, guint aKeyval);
+
+  GtkWidget* mNativeTarget;
+
+  static NativeKeyBindings* sInstanceForSingleLineEditor;
+  static NativeKeyBindings* sInstanceForMultiLineEditor;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // NativeKeyBindings_h
diff --git a/widget/gtk/NativeMenuGtk.cpp b/widget/gtk/NativeMenuGtk.cpp
new file mode 100644
index 0000000000..9d413d475e
--- /dev/null
+++ b/widget/gtk/NativeMenuGtk.cpp
@@ -0,0 +1,424 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "NativeMenuGtk.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/DocumentInlines.h"
+#include "mozilla/dom/XULCommandEvent.h"
+#include "mozilla/WidgetUtilsGtk.h"
+#include "mozilla/EventDispatcher.h"
+#include "nsPresContext.h"
+#include "nsIWidget.h"
+#include "nsWindow.h"
+#include "nsStubMutationObserver.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/StaticPrefs_widget.h"
+
+#include <dlfcn.h>
+#include <gtk/gtk.h>
+
+namespace mozilla::widget {
+
+using GtkMenuPopupAtRect = void (*)(GtkMenu* menu, GdkWindow* rect_window,
+                                    const GdkRectangle* rect,
+                                    GdkGravity rect_anchor,
+                                    GdkGravity menu_anchor,
+                                    const GdkEvent* trigger_event);
+
+static bool IsDisabled(const dom::Element& aElement) {
+  return aElement.AttrValueIs(kNameSpaceID_None, nsGkAtoms::disabled,
+                              nsGkAtoms::_true, eCaseMatters) ||
+         aElement.AttrValueIs(kNameSpaceID_None, nsGkAtoms::hidden,
+                              nsGkAtoms::_true, eCaseMatters);
+}
+static bool NodeIsRelevant(const nsINode& aNode) {
+  return aNode.IsAnyOfXULElements(nsGkAtoms::menu, nsGkAtoms::menuseparator,
+                                  nsGkAtoms::menuitem, nsGkAtoms::menugroup);
+}
+
+// If this is a radio / checkbox menuitem, get the current value.
+static Maybe<bool> GetChecked(const dom::Element& aMenuItem) {
+  static dom::Element::AttrValuesArray strings[] = {nsGkAtoms::checkbox,
+                                                    nsGkAtoms::radio, nullptr};
+  switch (aMenuItem.FindAttrValueIn(kNameSpaceID_None, nsGkAtoms::type, strings,
+                                    eCaseMatters)) {
+    case 0:
+      break;
+    case 1:
+      break;
+    default:
+      return Nothing();
+  }
+
+  return Some(aMenuItem.AttrValueIs(kNameSpaceID_None, nsGkAtoms::checked,
+                                    nsGkAtoms::_true, eCaseMatters));
+}
+
+struct Actions {
+  RefPtr<GSimpleActionGroup> mGroup;
+  size_t mNextActionIndex = 0;
+
+  nsPrintfCString Register(const dom::Element&, bool aForSubmenu);
+  void Clear();
+};
+
+static MOZ_CAN_RUN_SCRIPT void ActivateItem(dom::Element& aElement) {
+  if (Maybe<bool> checked = GetChecked(aElement)) {
+    if (!aElement.AttrValueIs(kNameSpaceID_None, nsGkAtoms::autocheck,
+                              nsGkAtoms::_false, eCaseMatters)) {
+      bool newValue = !*checked;
+      if (newValue) {
+        aElement.SetAttr(kNameSpaceID_None, nsGkAtoms::checked, u"true"_ns,
+                         true);
+      } else {
+        aElement.UnsetAttr(kNameSpaceID_None, nsGkAtoms::checked, true);
+      }
+    }
+  }
+
+  RefPtr doc = aElement.OwnerDoc();
+  RefPtr event = new dom::XULCommandEvent(doc, doc->GetPresContext(), nullptr);
+  IgnoredErrorResult rv;
+  event->InitCommandEvent(u"command"_ns, true, true,
+                          nsGlobalWindowInner::Cast(doc->GetInnerWindow()), 0,
+                          /* ctrlKey = */ false, /* altKey = */ false,
+                          /* shiftKey = */ false, /* cmdKey = */ false,
+                          /* button = */ MouseButton::ePrimary, nullptr, 0, rv);
+  if (MOZ_UNLIKELY(rv.Failed())) {
+    return;
+  }
+  aElement.DispatchEvent(*event);
+}
+
+static MOZ_CAN_RUN_SCRIPT void ActivateSignal(GSimpleAction* aAction,
+                                              GVariant* aParam,
+                                              gpointer aUserData) {
+  RefPtr element = static_cast<dom::Element*>(aUserData);
+  ActivateItem(*element);
+}
+
+static MOZ_CAN_RUN_SCRIPT void FireEvent(dom::Element* aTarget,
+                                         EventMessage aPopupMessage) {
+  nsEventStatus status = nsEventStatus_eIgnore;
+  WidgetMouseEvent event(true, aPopupMessage, nullptr, WidgetMouseEvent::eReal);
+  EventDispatcher::Dispatch(aTarget, nullptr, &event, nullptr, &status);
+}
+
+static MOZ_CAN_RUN_SCRIPT void ChangeStateSignal(GSimpleAction* aAction,
+                                                 GVariant* aParam,
+                                                 gpointer aUserData) {
+  // TODO: Fire events when safe. These run at a bad time for now.
+  static constexpr bool kEnabled = false;
+  if (!kEnabled) {
+    return;
+  }
+  const bool open = g_variant_get_boolean(aParam);
+  RefPtr popup = static_cast<dom::Element*>(aUserData);
+  if (open) {
+    FireEvent(popup, eXULPopupShowing);
+    FireEvent(popup, eXULPopupShown);
+  } else {
+    FireEvent(popup, eXULPopupHiding);
+    FireEvent(popup, eXULPopupHidden);
+  }
+}
+
+nsPrintfCString Actions::Register(const dom::Element& aMenuItem,
+                                  bool aForSubmenu) {
+  nsPrintfCString actionName("item-%zu", mNextActionIndex++);
+  Maybe<bool> paramValue = aForSubmenu ? Some(false) : GetChecked(aMenuItem);
+  RefPtr<GSimpleAction> action;
+  if (paramValue) {
+    action = dont_AddRef(g_simple_action_new_stateful(
+        actionName.get(), nullptr, g_variant_new_boolean(*paramValue)));
+  } else {
+    action = dont_AddRef(g_simple_action_new(actionName.get(), nullptr));
+  }
+  if (aForSubmenu) {
+    g_signal_connect(action, "change-state", G_CALLBACK(ChangeStateSignal),
+                     gpointer(&aMenuItem));
+  } else {
+    g_signal_connect(action, "activate", G_CALLBACK(ActivateSignal),
+                     gpointer(&aMenuItem));
+  }
+  g_action_map_add_action(G_ACTION_MAP(mGroup.get()), G_ACTION(action.get()));
+  return actionName;
+}
+
+void Actions::Clear() {
+  for (size_t i = 0; i < mNextActionIndex; ++i) {
+    g_action_map_remove_action(G_ACTION_MAP(mGroup.get()),
+                               nsPrintfCString("item-%zu", i).get());
+  }
+  mNextActionIndex = 0;
+}
+
+class MenuModel final : public nsStubMutationObserver {
+  NS_DECL_ISUPPORTS
+
+  NS_DECL_NSIMUTATIONOBSERVER_CONTENTREMOVED
+  NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
+  NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
+  NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
+
+ public:
+  explicit MenuModel(dom::Element* aElement) : mElement(aElement) {
+    mElement->AddMutationObserver(this);
+    mGMenu = dont_AddRef(g_menu_new());
+    mActions.mGroup = dont_AddRef(g_simple_action_group_new());
+  }
+
+  GMenuModel* GetModel() { return G_MENU_MODEL(mGMenu.get()); }
+  GActionGroup* GetActionGroup() {
+    return G_ACTION_GROUP(mActions.mGroup.get());
+  }
+
+  dom::Element* Element() { return mElement; }
+
+  void RecomputeModelIfNeeded();
+
+  bool IsShowing() { return mPoppedUp; }
+  void WillShow() {
+    mPoppedUp = true;
+    RecomputeModelIfNeeded();
+  }
+  void DidHide() { mPoppedUp = false; }
+
+ private:
+  virtual ~MenuModel() { mElement->RemoveMutationObserver(this); }
+
+  void DirtyModel() {
+    mDirty = true;
+    if (mPoppedUp) {
+      RecomputeModelIfNeeded();
+    }
+  }
+
+  RefPtr<dom::Element> mElement;
+  RefPtr<GMenu> mGMenu;
+  Actions mActions;
+  bool mDirty = true;
+  bool mPoppedUp = false;
+};
+
+NS_IMPL_ISUPPORTS(MenuModel, nsIMutationObserver)
+
+void MenuModel::ContentRemoved(nsIContent* aChild, nsIContent*) {
+  if (NodeIsRelevant(*aChild)) {
+    DirtyModel();
+  }
+}
+
+void MenuModel::ContentInserted(nsIContent* aChild) {
+  if (NodeIsRelevant(*aChild)) {
+    DirtyModel();
+  }
+}
+
+void MenuModel::ContentAppended(nsIContent* aChild) {
+  if (NodeIsRelevant(*aChild)) {
+    DirtyModel();
+  }
+}
+
+void MenuModel::AttributeChanged(dom::Element* aElement, int32_t aNameSpaceID,
+                                 nsAtom* aAttribute, int32_t aModType,
+                                 const nsAttrValue* aOldValue) {
+  if (NodeIsRelevant(*aElement) &&
+      (aAttribute == nsGkAtoms::label || aAttribute == nsGkAtoms::aria_label ||
+       aAttribute == nsGkAtoms::disabled || aAttribute == nsGkAtoms::hidden)) {
+    DirtyModel();
+  }
+}
+
+static const dom::Element* GetMenuPopupChild(const dom::Element& aElement) {
+  for (const nsIContent* child = aElement.GetFirstChild(); child;
+       child = child->GetNextSibling()) {
+    if (child->IsXULElement(nsGkAtoms::menupopup)) {
+      return child->AsElement();
+    }
+  }
+  return nullptr;
+}
+
+static void RecomputeModelFor(GMenu* aMenu, Actions& aActions,
+                              const dom::Element& aElement) {
+  RefPtr<GMenu> sectionMenu;
+  auto FlushSectionMenu = [&] {
+    if (sectionMenu) {
+      g_menu_append_section(aMenu, nullptr, G_MENU_MODEL(sectionMenu.get()));
+      sectionMenu = nullptr;
+    }
+  };
+
+  for (const nsIContent* child = aElement.GetFirstChild(); child;
+       child = child->GetNextSibling()) {
+    if (child->IsXULElement(nsGkAtoms::menuitem) &&
+        !IsDisabled(*child->AsElement())) {
+      nsAutoString label;
+      child->AsElement()->GetAttr(nsGkAtoms::label, label);
+      if (label.IsEmpty()) {
+        child->AsElement()->GetAttr(nsGkAtoms::aria_label, label);
+      }
+      nsPrintfCString actionName(
+          "menu.%s",
+          aActions.Register(*child->AsElement(), /* aForSubmenu = */ false)
+              .get());
+      g_menu_append(sectionMenu ? sectionMenu.get() : aMenu,
+                    NS_ConvertUTF16toUTF8(label).get(), actionName.get());
+      continue;
+    }
+    if (child->IsXULElement(nsGkAtoms::menuseparator)) {
+      FlushSectionMenu();
+      sectionMenu = dont_AddRef(g_menu_new());
+      continue;
+    }
+    if (child->IsXULElement(nsGkAtoms::menugroup)) {
+      FlushSectionMenu();
+      sectionMenu = dont_AddRef(g_menu_new());
+      RecomputeModelFor(sectionMenu, aActions, *child->AsElement());
+      FlushSectionMenu();
+      continue;
+    }
+    if (child->IsXULElement(nsGkAtoms::menu) &&
+        !IsDisabled(*child->AsElement())) {
+      if (const auto* popup = GetMenuPopupChild(*child->AsElement())) {
+        RefPtr<GMenu> submenu = dont_AddRef(g_menu_new());
+        RecomputeModelFor(submenu, aActions, *popup);
+        nsAutoString label;
+        child->AsElement()->GetAttr(nsGkAtoms::label, label);
+        RefPtr<GMenuItem> submenuItem = dont_AddRef(g_menu_item_new_submenu(
+            NS_ConvertUTF16toUTF8(label).get(), G_MENU_MODEL(submenu.get())));
+        nsPrintfCString actionName(
+            "menu.%s",
+            aActions.Register(*popup, /* aForSubmenu = */ true).get());
+        g_menu_item_set_attribute_value(submenuItem.get(), "submenu-action",
+                                        g_variant_new_string(actionName.get()));
+        g_menu_append_item(sectionMenu ? sectionMenu.get() : aMenu,
+                           submenuItem.get());
+      }
+    }
+  }
+
+  FlushSectionMenu();
+}
+
+void MenuModel::RecomputeModelIfNeeded() {
+  if (!mDirty) {
+    return;
+  }
+  mActions.Clear();
+  g_menu_remove_all(mGMenu.get());
+  RecomputeModelFor(mGMenu.get(), mActions, *mElement);
+}
+
+static GtkMenuPopupAtRect GetPopupAtRectFn() {
+  static GtkMenuPopupAtRect sFunc =
+      (GtkMenuPopupAtRect)dlsym(RTLD_DEFAULT, "gtk_menu_popup_at_rect");
+  return sFunc;
+}
+
+bool NativeMenuGtk::CanUse() {
+  return StaticPrefs::widget_gtk_native_context_menus() && GetPopupAtRectFn();
+}
+
+void NativeMenuGtk::FireEvent(EventMessage aPopupMessage) {
+  RefPtr target = Element();
+  widget::FireEvent(target, aPopupMessage);
+}
+
+#define METHOD_SIGNAL(name_)                                 \
+  static MOZ_CAN_RUN_SCRIPT_BOUNDARY void On##name_##Signal( \
+      GtkWidget* widget, gpointer user_data) {               \
+    RefPtr menu = static_cast<NativeMenuGtk*>(user_data);    \
+    return menu->On##name_();                                \
+  }
+
+METHOD_SIGNAL(Unmap);
+
+#undef METHOD_SIGNAL
+
+NativeMenuGtk::NativeMenuGtk(dom::Element* aElement)
+    : mMenuModel(MakeRefPtr<MenuModel>(aElement)) {
+  // Floating, so no need to dont_AddRef.
+  mNativeMenu = gtk_menu_new_from_model(mMenuModel->GetModel());
+  gtk_widget_insert_action_group(mNativeMenu.get(), "menu",
+                                 mMenuModel->GetActionGroup());
+  g_signal_connect(mNativeMenu, "unmap", G_CALLBACK(OnUnmapSignal), this);
+}
+
+NativeMenuGtk::~NativeMenuGtk() {
+  g_signal_handlers_disconnect_by_data(mNativeMenu, this);
+}
+
+RefPtr<dom::Element> NativeMenuGtk::Element() { return mMenuModel->Element(); }
+
+void NativeMenuGtk::ShowAsContextMenu(nsIFrame* aClickedFrame,
+                                      const CSSIntPoint& aPosition,
+                                      bool aIsContextMenu) {
+  if (mMenuModel->IsShowing()) {
+    return;
+  }
+  RefPtr<nsIWidget> widget = aClickedFrame->PresContext()->GetRootWidget();
+  if (NS_WARN_IF(!widget)) {
+    // XXX Do we need to close menus here?
+    return;
+  }
+  auto* win = static_cast<GdkWindow*>(widget->GetNativeData(NS_NATIVE_WINDOW));
+  if (NS_WARN_IF(!win)) {
+    return;
+  }
+
+  auto* geckoWin = static_cast<nsWindow*>(widget.get());
+  // The position needs to be relative to our window.
+  auto pos = (aPosition * aClickedFrame->PresContext()->CSSToDevPixelScale()) -
+             geckoWin->WidgetToScreenOffset();
+  auto gdkPos = geckoWin->DevicePixelsToGdkPointRoundDown(
+      LayoutDeviceIntPoint::Round(pos));
+
+  mMenuModel->WillShow();
+  const GdkRectangle rect = {gdkPos.x, gdkPos.y, 1, 1};
+  auto openFn = GetPopupAtRectFn();
+  openFn(GTK_MENU(mNativeMenu.get()), win, &rect, GDK_GRAVITY_NORTH_WEST,
+         GDK_GRAVITY_NORTH_WEST, GetLastMousePressEvent());
+
+  RefPtr pin{this};
+  FireEvent(eXULPopupShown);
+}
+
+bool NativeMenuGtk::Close() {
+  if (!mMenuModel->IsShowing()) {
+    return false;
+  }
+  gtk_menu_popdown(GTK_MENU(mNativeMenu.get()));
+  return true;
+}
+
+void NativeMenuGtk::OnUnmap() {
+  FireEvent(eXULPopupHiding);
+
+  mMenuModel->DidHide();
+
+  FireEvent(eXULPopupHidden);
+
+  for (NativeMenu::Observer* observer : mObservers.Clone()) {
+    observer->OnNativeMenuClosed();
+  }
+}
+
+void NativeMenuGtk::ActivateItem(dom::Element* aItemElement, Modifiers,
+                                 int16_t aButton, ErrorResult&) {
+  // TODO: For testing only.
+}
+
+void NativeMenuGtk::OpenSubmenu(dom::Element*) {
+  // TODO: For testing mostly.
+}
+
+void NativeMenuGtk::CloseSubmenu(dom::Element*) {
+  // TODO: For testing mostly.
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/NativeMenuGtk.h b/widget/gtk/NativeMenuGtk.h
new file mode 100644
index 0000000000..3f1f3213c1
--- /dev/null
+++ b/widget/gtk/NativeMenuGtk.h
@@ -0,0 +1,64 @@
+
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_NativeMenuGtk_h
+#define mozilla_widget_NativeMenuGtk_h
+
+#include "mozilla/widget/NativeMenu.h"
+#include "mozilla/EventForwards.h"
+#include "GRefPtr.h"
+
+namespace mozilla {
+
+namespace dom {
+class Element;
+}
+
+namespace widget {
+
+class MenuModel;
+
+class NativeMenuGtk : public NativeMenu {
+ public:
+  // Whether we can use native menu popups on GTK.
+  static bool CanUse();
+
+  explicit NativeMenuGtk(dom::Element* aElement);
+
+  // NativeMenu
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY void ShowAsContextMenu(
+      nsIFrame* aClickedFrame, const CSSIntPoint& aPosition,
+      bool aIsContextMenu) override;
+  bool Close() override;
+  void ActivateItem(dom::Element* aItemElement, Modifiers aModifiers,
+                    int16_t aButton, ErrorResult& aRv) override;
+  void OpenSubmenu(dom::Element* aMenuElement) override;
+  void CloseSubmenu(dom::Element* aMenuElement) override;
+  RefPtr<dom::Element> Element() override;
+  void AddObserver(NativeMenu::Observer* aObserver) override {
+    mObservers.AppendElement(aObserver);
+  }
+  void RemoveObserver(NativeMenu::Observer* aObserver) override {
+    mObservers.RemoveElement(aObserver);
+  }
+
+  MOZ_CAN_RUN_SCRIPT void OnUnmap();
+
+ protected:
+  virtual ~NativeMenuGtk();
+
+  MOZ_CAN_RUN_SCRIPT void FireEvent(EventMessage);
+
+  bool mPoppedUp = false;
+  RefPtr<GtkWidget> mNativeMenu;
+  RefPtr<MenuModel> mMenuModel;
+  nsTArray<NativeMenu::Observer*> mObservers;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/gtk/NativeMenuSupport.cpp b/widget/gtk/NativeMenuSupport.cpp
new file mode 100644
index 0000000000..4360867fff
--- /dev/null
+++ b/widget/gtk/NativeMenuSupport.cpp
@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/widget/NativeMenuSupport.h"
+
+#include "MainThreadUtils.h"
+#include "NativeMenuGtk.h"
+
+namespace mozilla::widget {
+
+void NativeMenuSupport::CreateNativeMenuBar(nsIWidget* aParent,
+                                            dom::Element* aMenuBarElement) {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread(),
+                     "Attempting to create native menu bar on wrong thread!");
+  // TODO
+}
+
+already_AddRefed<NativeMenu> NativeMenuSupport::CreateNativeContextMenu(
+    dom::Element* aPopup) {
+  return MakeAndAddRef<NativeMenuGtk>(aPopup);
+}
+
+bool NativeMenuSupport::ShouldUseNativeContextMenus() {
+  return NativeMenuGtk::CanUse();
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/PCompositorWidget.ipdl b/widget/gtk/PCompositorWidget.ipdl
new file mode 100644
index 0000000000..d554a33144
--- /dev/null
+++ b/widget/gtk/PCompositorWidget.ipdl
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=99: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PCompositorBridge;
+
+include "mozilla/GfxMessageUtils.h";
+
+using mozilla::LayoutDeviceIntSize from "Units.h";
+
+namespace mozilla {
+namespace widget {
+
+[ManualDealloc, ChildImpl=virtual, ParentImpl=virtual]
+sync protocol PCompositorWidget
+{
+  manager PCompositorBridge;
+
+parent:
+  async __delete__();
+
+  async NotifyClientSizeChanged(LayoutDeviceIntSize aClientSize);
+  async DisableRendering();
+  async EnableRendering(uintptr_t aXWindow, bool aShaped);
+
+child:
+
+  async ObserveVsync();
+  async UnobserveVsync();
+};
+
+} // namespace widget
+} // namespace mozilla
diff --git a/widget/gtk/PlatformWidgetTypes.ipdlh b/widget/gtk/PlatformWidgetTypes.ipdlh
new file mode 100644
index 0000000000..c85da1711e
--- /dev/null
+++ b/widget/gtk/PlatformWidgetTypes.ipdlh
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=99: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include HeadlessWidgetTypes;
+
+include "mozilla/GfxMessageUtils.h";
+
+using mozilla::LayoutDeviceIntSize from "Units.h";
+
+namespace mozilla {
+namespace widget {
+
+struct GtkCompositorWidgetInitData
+{
+  uintptr_t           XWindow;
+  nsCString           XDisplayString;
+  bool                Shaped;
+  bool                IsX11Display;
+
+  LayoutDeviceIntSize InitialClientSize;
+};
+
+union CompositorWidgetInitData
+{
+  GtkCompositorWidgetInitData;
+  HeadlessCompositorWidgetInitData;
+};
+
+} // namespace widget
+} // namespace mozilla
diff --git a/widget/gtk/ScreenHelperGTK.cpp b/widget/gtk/ScreenHelperGTK.cpp
new file mode 100644
index 0000000000..60be234c60
--- /dev/null
+++ b/widget/gtk/ScreenHelperGTK.cpp
@@ -0,0 +1,306 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScreenHelperGTK.h"
+
+#ifdef MOZ_X11
+#  include <gdk/gdkx.h>
+#  include <X11/Xlib.h>
+#  include "X11UndefineNone.h"
+#endif /* MOZ_X11 */
+#ifdef MOZ_WAYLAND
+#  include <gdk/gdkwayland.h>
+#endif /* MOZ_WAYLAND */
+#include <dlfcn.h>
+#include <gtk/gtk.h>
+
+#include "gfxPlatformGtk.h"
+#include "mozilla/dom/DOMTypes.h"
+#include "mozilla/Logging.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/WidgetUtilsGtk.h"
+#include "nsGtkUtils.h"
+#include "nsTArray.h"
+#include "nsWindow.h"
+
+struct wl_registry;
+
+#ifdef MOZ_WAYLAND
+#  include "nsWaylandDisplay.h"
+#endif
+
+namespace mozilla::widget {
+
+#ifdef MOZ_LOGGING
+static LazyLogModule sScreenLog("WidgetScreen");
+#  define LOG_SCREEN(...) MOZ_LOG(sScreenLog, LogLevel::Debug, (__VA_ARGS__))
+#else
+#  define LOG_SCREEN(...)
+#endif /* MOZ_LOGGING */
+
+using GdkMonitor = struct _GdkMonitor;
+
+class ScreenGetterGtk final {
+ public:
+  ScreenGetterGtk() = default;
+  ~ScreenGetterGtk();
+
+  void Init();
+
+#ifdef MOZ_X11
+  Atom NetWorkareaAtom() { return mNetWorkareaAtom; }
+#endif
+
+  // For internal use from signal callback functions
+  void RefreshScreens();
+
+ private:
+  GdkWindow* mRootWindow = nullptr;
+#ifdef MOZ_X11
+  Atom mNetWorkareaAtom = 0;
+#endif
+};
+
+static GdkMonitor* GdkDisplayGetMonitor(GdkDisplay* aDisplay, int aMonitorNum) {
+  static auto s_gdk_display_get_monitor = (GdkMonitor * (*)(GdkDisplay*, int))
+      dlsym(RTLD_DEFAULT, "gdk_display_get_monitor");
+  if (!s_gdk_display_get_monitor) {
+    return nullptr;
+  }
+  return s_gdk_display_get_monitor(aDisplay, aMonitorNum);
+}
+
+RefPtr<Screen> ScreenHelperGTK::GetScreenForWindow(nsWindow* aWindow) {
+  LOG_SCREEN("GetScreenForWindow() [%p]", aWindow);
+
+  static auto s_gdk_display_get_monitor_at_window =
+      (GdkMonitor * (*)(GdkDisplay*, GdkWindow*))
+          dlsym(RTLD_DEFAULT, "gdk_display_get_monitor_at_window");
+
+  if (!s_gdk_display_get_monitor_at_window) {
+    LOG_SCREEN("  failed, missing Gtk helpers");
+    return nullptr;
+  }
+
+  GdkWindow* gdkWindow = aWindow->GetToplevelGdkWindow();
+  if (!gdkWindow) {
+    LOG_SCREEN("  failed, can't get GdkWindow");
+    return nullptr;
+  }
+
+  GdkDisplay* display = gdk_display_get_default();
+  GdkMonitor* monitor = s_gdk_display_get_monitor_at_window(display, gdkWindow);
+  if (!monitor) {
+    LOG_SCREEN("  failed, can't get monitor for GdkWindow");
+    return nullptr;
+  }
+
+  int index = -1;
+  while (GdkMonitor* m = GdkDisplayGetMonitor(display, ++index)) {
+    if (m == monitor) {
+      return ScreenManager::GetSingleton().CurrentScreenList().SafeElementAt(
+          index);
+    }
+  }
+
+  LOG_SCREEN("  Couldn't find monitor %p", monitor);
+  return nullptr;
+}
+
+static StaticAutoPtr<ScreenGetterGtk> gScreenGetter;
+
+static void monitors_changed(GdkScreen* aScreen, gpointer aClosure) {
+  LOG_SCREEN("Received monitors-changed event");
+  auto* self = static_cast<ScreenGetterGtk*>(aClosure);
+  self->RefreshScreens();
+}
+
+static void screen_resolution_changed(GdkScreen* aScreen, GParamSpec* aPspec,
+                                      ScreenGetterGtk* self) {
+  self->RefreshScreens();
+}
+
+static GdkFilterReturn root_window_event_filter(GdkXEvent* aGdkXEvent,
+                                                GdkEvent* aGdkEvent,
+                                                gpointer aClosure) {
+#ifdef MOZ_X11
+  ScreenGetterGtk* self = static_cast<ScreenGetterGtk*>(aClosure);
+  XEvent* xevent = static_cast<XEvent*>(aGdkXEvent);
+
+  switch (xevent->type) {
+    case PropertyNotify: {
+      XPropertyEvent* propertyEvent = &xevent->xproperty;
+      if (propertyEvent->atom == self->NetWorkareaAtom()) {
+        LOG_SCREEN("Work area size changed");
+        self->RefreshScreens();
+      }
+    } break;
+    default:
+      break;
+  }
+#endif
+
+  return GDK_FILTER_CONTINUE;
+}
+
+void ScreenGetterGtk::Init() {
+  LOG_SCREEN("ScreenGetterGtk created");
+  GdkScreen* defaultScreen = gdk_screen_get_default();
+  if (!defaultScreen) {
+    // Sometimes we don't initial X (e.g., xpcshell)
+    MOZ_LOG(sScreenLog, LogLevel::Debug,
+            ("defaultScreen is nullptr, running headless"));
+    return;
+  }
+  mRootWindow = gdk_get_default_root_window();
+  MOZ_ASSERT(mRootWindow);
+
+  g_object_ref(mRootWindow);
+
+  // GDK_PROPERTY_CHANGE_MASK ==> PropertyChangeMask, for PropertyNotify
+  gdk_window_set_events(mRootWindow,
+                        GdkEventMask(gdk_window_get_events(mRootWindow) |
+                                     GDK_PROPERTY_CHANGE_MASK));
+
+  g_signal_connect(defaultScreen, "monitors-changed",
+                   G_CALLBACK(monitors_changed), this);
+  // Use _after to ensure this callback is run after gfxPlatformGtk.cpp's
+  // handler.
+  g_signal_connect_after(defaultScreen, "notify::resolution",
+                         G_CALLBACK(screen_resolution_changed), this);
+#ifdef MOZ_X11
+  gdk_window_add_filter(mRootWindow, root_window_event_filter, this);
+  if (GdkIsX11Display()) {
+    mNetWorkareaAtom = XInternAtom(GDK_WINDOW_XDISPLAY(mRootWindow),
+                                   "_NET_WORKAREA", X11False);
+  }
+#endif
+  RefreshScreens();
+}
+
+ScreenGetterGtk::~ScreenGetterGtk() {
+  if (mRootWindow) {
+    g_signal_handlers_disconnect_by_data(gdk_screen_get_default(), this);
+
+    gdk_window_remove_filter(mRootWindow, root_window_event_filter, this);
+    g_object_unref(mRootWindow);
+    mRootWindow = nullptr;
+  }
+}
+
+static uint32_t GetGTKPixelDepth() {
+  GdkVisual* visual = gdk_screen_get_system_visual(gdk_screen_get_default());
+  return gdk_visual_get_depth(visual);
+}
+
+static already_AddRefed<Screen> MakeScreenGtk(GdkScreen* aScreen,
+                                              gint aMonitorNum) {
+  gint gdkScaleFactor = ScreenHelperGTK::GetGTKMonitorScaleFactor(aMonitorNum);
+
+  // gdk_screen_get_monitor_geometry / workarea returns application pixels
+  // (desktop pixels), so we need to convert it to device pixels with
+  // gdkScaleFactor.
+  gint geometryScaleFactor = gdkScaleFactor;
+
+  gint refreshRate = [&] {
+    // Since gtk 3.22
+    static auto s_gdk_monitor_get_refresh_rate = (int (*)(GdkMonitor*))dlsym(
+        RTLD_DEFAULT, "gdk_monitor_get_refresh_rate");
+
+    if (!s_gdk_monitor_get_refresh_rate) {
+      return 0;
+    }
+    GdkMonitor* monitor =
+        GdkDisplayGetMonitor(gdk_display_get_default(), aMonitorNum);
+    if (!monitor) {
+      return 0;
+    }
+    // Convert to Hz.
+    return NSToIntRound(s_gdk_monitor_get_refresh_rate(monitor) / 1000.0f);
+  }();
+
+  GdkRectangle workarea;
+  gdk_screen_get_monitor_workarea(aScreen, aMonitorNum, &workarea);
+  LayoutDeviceIntRect availRect(workarea.x * geometryScaleFactor,
+                                workarea.y * geometryScaleFactor,
+                                workarea.width * geometryScaleFactor,
+                                workarea.height * geometryScaleFactor);
+  LayoutDeviceIntRect rect;
+  DesktopToLayoutDeviceScale contentsScale(1.0);
+  if (GdkIsX11Display()) {
+    GdkRectangle monitor;
+    gdk_screen_get_monitor_geometry(aScreen, aMonitorNum, &monitor);
+    rect = LayoutDeviceIntRect(monitor.x * geometryScaleFactor,
+                               monitor.y * geometryScaleFactor,
+                               monitor.width * geometryScaleFactor,
+                               monitor.height * geometryScaleFactor);
+  } else {
+    // Don't report screen shift in Wayland, see bug 1795066.
+    availRect.MoveTo(0, 0);
+    // We use Gtk workarea on Wayland as it matches our needs (Bug 1732682).
+    rect = availRect;
+    // Use per-monitor scaling factor in Wayland.
+    contentsScale.scale = gdkScaleFactor;
+  }
+
+  uint32_t pixelDepth = GetGTKPixelDepth();
+  if (pixelDepth == 32) {
+    // If a device uses 32 bits per pixel, it's still only using 8 bits
+    // per color component, which is what our callers want to know.
+    // (Some devices report 32 and some devices report 24.)
+    pixelDepth = 24;
+  }
+
+  CSSToLayoutDeviceScale defaultCssScale(gdkScaleFactor);
+
+  float dpi = 96.0f;
+  gint heightMM = gdk_screen_get_monitor_height_mm(aScreen, aMonitorNum);
+  if (heightMM > 0) {
+    dpi = rect.height / (heightMM / MM_PER_INCH_FLOAT);
+  }
+
+  LOG_SCREEN(
+      "New monitor %d size [%d,%d -> %d x %d] depth %d scale %f CssScale %f  "
+      "DPI %f refresh %d ]",
+      aMonitorNum, rect.x, rect.y, rect.width, rect.height, pixelDepth,
+      contentsScale.scale, defaultCssScale.scale, dpi, refreshRate);
+  return MakeAndAddRef<Screen>(rect, availRect, pixelDepth, pixelDepth,
+                               refreshRate, contentsScale, defaultCssScale, dpi,
+                               Screen::IsPseudoDisplay::No);
+}
+
+void ScreenGetterGtk::RefreshScreens() {
+  LOG_SCREEN("ScreenGetterGtk::RefreshScreens()");
+  AutoTArray<RefPtr<Screen>, 4> screenList;
+
+  GdkScreen* defaultScreen = gdk_screen_get_default();
+  gint numScreens = gdk_screen_get_n_monitors(defaultScreen);
+  LOG_SCREEN("GDK reports %d screens", numScreens);
+
+  for (gint i = 0; i < numScreens; i++) {
+    screenList.AppendElement(MakeScreenGtk(defaultScreen, i));
+  }
+
+  ScreenManager::Refresh(std::move(screenList));
+}
+
+gint ScreenHelperGTK::GetGTKMonitorScaleFactor(gint aMonitorNum) {
+  GdkScreen* screen = gdk_screen_get_default();
+  return gdk_screen_get_monitor_scale_factor(screen, aMonitorNum);
+}
+
+ScreenHelperGTK::ScreenHelperGTK() {
+  gScreenGetter = new ScreenGetterGtk();
+  gScreenGetter->Init();
+}
+
+int ScreenHelperGTK::GetMonitorCount() {
+  return gdk_screen_get_n_monitors(gdk_screen_get_default());
+}
+
+ScreenHelperGTK::~ScreenHelperGTK() { gScreenGetter = nullptr; }
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/ScreenHelperGTK.h b/widget/gtk/ScreenHelperGTK.h
new file mode 100644
index 0000000000..b9efb67746
--- /dev/null
+++ b/widget/gtk/ScreenHelperGTK.h
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_gtk_ScreenHelperGTK_h
+#define mozilla_widget_gtk_ScreenHelperGTK_h
+
+#include "mozilla/widget/ScreenManager.h"
+
+#include "gdk/gdk.h"
+
+class nsWindow;
+
+namespace mozilla::widget {
+
+class ScreenHelperGTK final : public ScreenManager::Helper {
+ public:
+  ScreenHelperGTK();
+  ~ScreenHelperGTK();
+
+  static int GetMonitorCount();
+  static gint GetGTKMonitorScaleFactor(gint aMonitorNum = 0);
+  static RefPtr<widget::Screen> GetScreenForWindow(nsWindow* aWindow);
+};
+
+}  // namespace mozilla::widget
+
+#endif  // mozilla_widget_gtk_ScreenHelperGTK_h
diff --git a/widget/gtk/TaskbarProgress.cpp b/widget/gtk/TaskbarProgress.cpp
new file mode 100644
index 0000000000..396f39b5e7
--- /dev/null
+++ b/widget/gtk/TaskbarProgress.cpp
@@ -0,0 +1,106 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Logging.h"
+
+#include "TaskbarProgress.h"
+#include "nsWindow.h"
+#include "WidgetUtils.h"
+#include "nsPIDOMWindow.h"
+
+using mozilla::LogLevel;
+static mozilla::LazyLogModule gGtkTaskbarProgressLog("nsIGtkTaskbarProgress");
+
+/******************************************************************************
+ * TaskbarProgress
+ ******************************************************************************/
+
+NS_IMPL_ISUPPORTS(TaskbarProgress, nsIGtkTaskbarProgress, nsITaskbarProgress)
+
+TaskbarProgress::TaskbarProgress() : mPrimaryWindow(nullptr) {
+  MOZ_LOG(gGtkTaskbarProgressLog, LogLevel::Info,
+          ("%p TaskbarProgress()", this));
+}
+
+TaskbarProgress::~TaskbarProgress() {
+  MOZ_LOG(gGtkTaskbarProgressLog, LogLevel::Info,
+          ("%p ~TaskbarProgress()", this));
+}
+
+NS_IMETHODIMP
+TaskbarProgress::SetProgressState(nsTaskbarProgressState aState,
+                                  uint64_t aCurrentValue, uint64_t aMaxValue) {
+  NS_ENSURE_ARG_RANGE(aState, 0, STATE_PAUSED);
+
+  if (aState == STATE_NO_PROGRESS || aState == STATE_INDETERMINATE) {
+    NS_ENSURE_TRUE(aCurrentValue == 0, NS_ERROR_INVALID_ARG);
+    NS_ENSURE_TRUE(aMaxValue == 0, NS_ERROR_INVALID_ARG);
+  }
+
+  NS_ENSURE_TRUE((aCurrentValue <= aMaxValue), NS_ERROR_ILLEGAL_VALUE);
+
+  // See TaskbarProgress::SetPrimaryWindow: if we're running in headless
+  // mode, mPrimaryWindow will be null.
+  if (!mPrimaryWindow) {
+    return NS_OK;
+  }
+
+  gulong progress;
+
+  if (aMaxValue == 0) {
+    progress = 0;
+  } else {
+    // Rounding down to ensure we don't set to 'full' until the operation
+    // is completely finished.
+    progress = (gulong)(((double)aCurrentValue / aMaxValue) * 100.0);
+  }
+
+  // Check if the resultant value is the same as the previous call, and
+  // ignore this update if it is.
+
+  if (progress == mCurrentProgress) {
+    return NS_OK;
+  }
+
+  mCurrentProgress = progress;
+
+  MOZ_LOG(gGtkTaskbarProgressLog, LogLevel::Debug,
+          ("GtkTaskbarProgress::SetProgressState progress: %lu", progress));
+
+  mPrimaryWindow->SetProgress(progress);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarProgress::SetPrimaryWindow(mozIDOMWindowProxy* aWindow) {
+  NS_ENSURE_TRUE(aWindow != nullptr, NS_ERROR_ILLEGAL_VALUE);
+
+  auto* parent = nsPIDOMWindowOuter::From(aWindow);
+  RefPtr<nsIWidget> widget =
+      mozilla::widget::WidgetUtils::DOMWindowToWidget(parent);
+
+  // Only nsWindows have a native window, HeadlessWidgets do not.  Stop here if
+  // the window does not have one.
+  if (!widget->GetNativeData(NS_NATIVE_WINDOW)) {
+    return NS_OK;
+  }
+
+  mPrimaryWindow = static_cast<nsWindow*>(widget.get());
+
+  // Clear our current progress.  We get a forced update from the
+  // DownloadsTaskbar after returning from this function - zeroing out our
+  // progress will make sure the new window gets the property set on it
+  // immediately, rather than waiting for the progress value to change (which
+  // could be a while depending on size.)
+  mCurrentProgress = 0;
+
+  MOZ_LOG(gGtkTaskbarProgressLog, LogLevel::Debug,
+          ("GtkTaskbarProgress::SetPrimaryWindow window: %p",
+           mPrimaryWindow.get()));
+
+  return NS_OK;
+}
diff --git a/widget/gtk/TaskbarProgress.h b/widget/gtk/TaskbarProgress.h
new file mode 100644
index 0000000000..819df0c089
--- /dev/null
+++ b/widget/gtk/TaskbarProgress.h
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef TaskbarProgress_h_
+#define TaskbarProgress_h_
+
+#include "nsIGtkTaskbarProgress.h"
+
+class nsWindow;
+
+class TaskbarProgress final : public nsIGtkTaskbarProgress {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIGTKTASKBARPROGRESS
+  NS_DECL_NSITASKBARPROGRESS
+
+  TaskbarProgress();
+
+ protected:
+  ~TaskbarProgress();
+
+  // We track the progress value so we can avoid updating the X window property
+  // unnecessarily.
+  unsigned long mCurrentProgress;
+
+  RefPtr<nsWindow> mPrimaryWindow;
+};
+
+#endif  // #ifndef TaskbarProgress_h_
diff --git a/widget/gtk/WakeLockListener.cpp b/widget/gtk/WakeLockListener.cpp
new file mode 100644
index 0000000000..b2c43cb485
--- /dev/null
+++ b/widget/gtk/WakeLockListener.cpp
@@ -0,0 +1,913 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WakeLockListener.h"
+#include "WidgetUtilsGtk.h"
+#include "mozilla/ScopeExit.h"
+
+#ifdef MOZ_ENABLE_DBUS
+#  include <gio/gio.h>
+#  include "AsyncDBus.h"
+#endif
+
+#if defined(MOZ_X11)
+#  include "prlink.h"
+#  include <gdk/gdk.h>
+#  include <gdk/gdkx.h>
+#  include "X11UndefineNone.h"
+#endif
+
+#if defined(MOZ_WAYLAND)
+#  include "mozilla/widget/nsWaylandDisplay.h"
+#  include "nsWindow.h"
+#endif
+
+#ifdef MOZ_ENABLE_DBUS
+#  define FREEDESKTOP_PORTAL_DESKTOP_TARGET "org.freedesktop.portal.Desktop"
+#  define FREEDESKTOP_PORTAL_DESKTOP_OBJECT "/org/freedesktop/portal/desktop"
+#  define FREEDESKTOP_PORTAL_DESKTOP_INTERFACE "org.freedesktop.portal.Inhibit"
+#  define FREEDESKTOP_PORTAL_DESKTOP_INHIBIT_IDLE_FLAG 8
+
+#  define FREEDESKTOP_SCREENSAVER_TARGET "org.freedesktop.ScreenSaver"
+#  define FREEDESKTOP_SCREENSAVER_OBJECT "/ScreenSaver"
+#  define FREEDESKTOP_SCREENSAVER_INTERFACE "org.freedesktop.ScreenSaver"
+
+#  define FREEDESKTOP_POWER_TARGET "org.freedesktop.PowerManagement"
+#  define FREEDESKTOP_POWER_OBJECT "/org/freedesktop/PowerManagement/Inhibit"
+#  define FREEDESKTOP_POWER_INTERFACE "org.freedesktop.PowerManagement.Inhibit"
+
+#  define SESSION_MANAGER_TARGET "org.gnome.SessionManager"
+#  define SESSION_MANAGER_OBJECT "/org/gnome/SessionManager"
+#  define SESSION_MANAGER_INTERFACE "org.gnome.SessionManager"
+
+#  define DBUS_TIMEOUT (-1)
+#endif
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+NS_IMPL_ISUPPORTS(WakeLockListener, nsIDOMMozWakeLockListener)
+
+#define WAKE_LOCK_LOG(str, ...)                        \
+  MOZ_LOG(gLinuxWakeLockLog, mozilla::LogLevel::Debug, \
+          ("[%p] " str, this, ##__VA_ARGS__))
+static mozilla::LazyLogModule gLinuxWakeLockLog("LinuxWakeLock");
+
+enum WakeLockType {
+  Initial = 0,
+#if defined(MOZ_ENABLE_DBUS)
+  FreeDesktopScreensaver = 1,
+  FreeDesktopPower = 2,
+  FreeDesktopPortal = 3,
+  GNOME = 4,
+#endif
+#if defined(MOZ_X11)
+  XScreenSaver = 5,
+#endif
+#if defined(MOZ_WAYLAND)
+  WaylandIdleInhibit = 6,
+#endif
+  Unsupported = 7,
+};
+
+#if defined(MOZ_ENABLE_DBUS)
+bool IsDBusWakeLock(int aWakeLockType) {
+  switch (aWakeLockType) {
+    case FreeDesktopScreensaver:
+    case FreeDesktopPower:
+    case GNOME:
+    case FreeDesktopPortal:
+      return true;
+    default:
+      return false;
+  }
+}
+#endif
+
+#ifdef MOZ_LOGGING
+const char* WakeLockTypeNames[] = {
+    "Initial",
+    "FreeDesktopScreensaver",
+    "FreeDesktopPower",
+    "FreeDesktopPortal",
+    "GNOME",
+    "XScreenSaver",
+    "WaylandIdleInhibit",
+    "Unsupported",
+};
+#endif
+
+class WakeLockTopic {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(WakeLockTopic)
+
+  explicit WakeLockTopic(const nsAString& aTopic) {
+    CopyUTF16toUTF8(aTopic, mTopic);
+    WAKE_LOCK_LOG("WakeLockTopic::WakeLockTopic() created %s", mTopic.get());
+    if (sWakeLockType == Initial) {
+      SwitchToNextWakeLockType();
+    }
+#ifdef MOZ_ENABLE_DBUS
+    mCancellable = dont_AddRef(g_cancellable_new());
+#endif
+  }
+
+  nsresult InhibitScreensaver();
+  nsresult UninhibitScreensaver();
+
+  void Shutdown();
+
+ private:
+  bool SendInhibit();
+  bool SendUninhibit();
+
+#if defined(MOZ_X11)
+  bool CheckXScreenSaverSupport();
+  bool InhibitXScreenSaver(bool inhibit);
+#endif
+
+#if defined(MOZ_WAYLAND)
+  zwp_idle_inhibitor_v1* mWaylandInhibitor = nullptr;
+  static bool CheckWaylandIdleInhibitSupport();
+  bool InhibitWaylandIdle();
+  bool UninhibitWaylandIdle();
+#endif
+
+  bool IsWakeLockTypeAvailable(int aWakeLockType);
+  bool SwitchToNextWakeLockType();
+
+#ifdef MOZ_ENABLE_DBUS
+  void DBusInhibitScreensaver(const char* aName, const char* aPath,
+                              const char* aCall, const char* aMethod,
+                              RefPtr<GVariant> aArgs);
+  void DBusUninhibitScreensaver(const char* aName, const char* aPath,
+                                const char* aCall, const char* aMethod);
+
+  void InhibitFreeDesktopPortal();
+  void InhibitFreeDesktopScreensaver();
+  void InhibitFreeDesktopPower();
+  void InhibitGNOME();
+
+  void UninhibitFreeDesktopPortal();
+  void UninhibitFreeDesktopScreensaver();
+  void UninhibitFreeDesktopPower();
+  void UninhibitGNOME();
+
+  void DBusInhibitSucceeded(uint32_t aInhibitRequestID);
+  void DBusInhibitFailed(bool aFatal);
+  void DBusUninhibitSucceeded();
+  void DBusUninhibitFailed();
+  void ClearDBusInhibitToken();
+#endif
+  ~WakeLockTopic() = default;
+
+  // Why is screensaver inhibited
+  nsCString mTopic;
+
+  // Our desired state
+  bool mShouldInhibit = false;
+
+  // Our actual sate
+  bool mInhibited = false;
+
+#ifdef MOZ_ENABLE_DBUS
+  // We're waiting for DBus reply (inhibit/uninhibit calls).
+  bool mWaitingForDBusInhibit = false;
+  bool mWaitingForDBusUninhibit = false;
+
+  // mInhibitRequestID is received from success screen saver inhibit call
+  // and it's needed for screen saver enablement.
+  Maybe<uint32_t> mInhibitRequestID;
+
+  RefPtr<GCancellable> mCancellable;
+  // Used to uninhibit org.freedesktop.portal.Inhibit request
+  nsCString mRequestObjectPath;
+#endif
+
+  static int sWakeLockType;
+};
+
+int WakeLockTopic::sWakeLockType = Initial;
+
+#ifdef MOZ_ENABLE_DBUS
+void WakeLockTopic::DBusInhibitSucceeded(uint32_t aInhibitRequestID) {
+  mWaitingForDBusInhibit = false;
+  mInhibitRequestID = Some(aInhibitRequestID);
+  mInhibited = true;
+
+  WAKE_LOCK_LOG(
+      "WakeLockTopic::DBusInhibitSucceeded(), mInhibitRequestID %u "
+      "mShouldInhibit %d",
+      *mInhibitRequestID, mShouldInhibit);
+
+  // Uninhibit was requested before inhibit request was finished.
+  // So ask for it now.
+  if (!mShouldInhibit) {
+    UninhibitScreensaver();
+  }
+}
+
+void WakeLockTopic::DBusInhibitFailed(bool aFatal) {
+  WAKE_LOCK_LOG("WakeLockTopic::DBusInhibitFailed(%d)", aFatal);
+
+  mWaitingForDBusInhibit = false;
+  ClearDBusInhibitToken();
+
+  // Non-recoverable DBus error. Switch to another wake lock type.
+  if (aFatal && SwitchToNextWakeLockType()) {
+    SendInhibit();
+  }
+}
+
+void WakeLockTopic::DBusUninhibitSucceeded() {
+  WAKE_LOCK_LOG("WakeLockTopic::DBusUninhibitSucceeded() mShouldInhibit %d",
+                mShouldInhibit);
+
+  mWaitingForDBusUninhibit = false;
+  mInhibited = false;
+  ClearDBusInhibitToken();
+
+  // Inhibit was requested before uninhibit request was finished.
+  // So ask for it now.
+  if (mShouldInhibit) {
+    InhibitScreensaver();
+  }
+}
+
+void WakeLockTopic::DBusUninhibitFailed() {
+  WAKE_LOCK_LOG("WakeLockTopic::DBusUninhibitFailed()");
+  mWaitingForDBusUninhibit = false;
+  mInhibitRequestID = Nothing();
+}
+
+void WakeLockTopic::ClearDBusInhibitToken() {
+  mRequestObjectPath.Truncate();
+  mInhibitRequestID = Nothing();
+}
+
+void WakeLockTopic::DBusInhibitScreensaver(const char* aName, const char* aPath,
+                                           const char* aCall,
+                                           const char* aMethod,
+                                           RefPtr<GVariant> aArgs) {
+  WAKE_LOCK_LOG(
+      "WakeLockTopic::DBusInhibitScreensaver() mWaitingForDBusInhibit %d "
+      "mWaitingForDBusUninhibit %d",
+      mWaitingForDBusInhibit, mWaitingForDBusUninhibit);
+  if (mWaitingForDBusInhibit) {
+    WAKE_LOCK_LOG("  already waiting to inihibit, return");
+    return;
+  }
+  if (mWaitingForDBusUninhibit) {
+    WAKE_LOCK_LOG("  cancel un-inihibit request");
+    g_cancellable_cancel(mCancellable);
+    mWaitingForDBusUninhibit = false;
+  }
+  mWaitingForDBusInhibit = true;
+
+  widget::CreateDBusProxyForBus(
+      G_BUS_TYPE_SESSION,
+      GDBusProxyFlags(G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS |
+                      G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES),
+      /* aInterfaceInfo = */ nullptr, aName, aPath, aCall, mCancellable)
+      ->Then(
+          GetCurrentSerialEventTarget(), __func__,
+          [self = RefPtr{this}, this, args = RefPtr{aArgs},
+           aMethod](RefPtr<GDBusProxy>&& aProxy) {
+            WAKE_LOCK_LOG(
+                "WakeLockTopic::DBusInhibitScreensaver() proxy created");
+            DBusProxyCall(aProxy.get(), aMethod, args.get(),
+                          G_DBUS_CALL_FLAGS_NONE, DBUS_TIMEOUT, mCancellable)
+                ->Then(
+                    GetCurrentSerialEventTarget(), __func__,
+                    [s = RefPtr{this}, this](RefPtr<GVariant>&& aResult) {
+                      if (!g_variant_is_of_type(aResult.get(),
+                                                G_VARIANT_TYPE_TUPLE) ||
+                          g_variant_n_children(aResult.get()) != 1) {
+                        WAKE_LOCK_LOG(
+                            "WakeLockTopic::DBusInhibitScreensaver() wrong "
+                            "reply type %s\n",
+                            g_variant_get_type_string(aResult.get()));
+                        DBusInhibitFailed(/* aFatal */ true);
+                        return;
+                      }
+                      RefPtr<GVariant> variant = dont_AddRef(
+                          g_variant_get_child_value(aResult.get(), 0));
+                      if (!g_variant_is_of_type(variant,
+                                                G_VARIANT_TYPE_UINT32)) {
+                        WAKE_LOCK_LOG(
+                            "WakeLockTopic::DBusInhibitScreensaver() wrong "
+                            "reply type %s\n",
+                            g_variant_get_type_string(aResult.get()));
+                        DBusInhibitFailed(/* aFatal */ true);
+                        return;
+                      }
+                      DBusInhibitSucceeded(g_variant_get_uint32(variant));
+                    },
+                    [s = RefPtr{this}, this,
+                     aMethod](GUniquePtr<GError>&& aError) {
+                      // Failed to send inhibit request over proxy.
+                      // Switch to another wake lock type.
+                      WAKE_LOCK_LOG(
+                          "WakeLockTopic::DBusInhibitFailed() %s call failed : "
+                          "%s\n",
+                          aMethod, aError->message);
+                      DBusInhibitFailed(
+                          /* aFatal */ !IsCancelledGError(aError.get()));
+                    });
+          },
+          [self = RefPtr{this}, this](GUniquePtr<GError>&& aError) {
+            // We failed to create DBus proxy. Switch to another
+            // wake lock type.
+            WAKE_LOCK_LOG(
+                "WakeLockTopic::DBusInhibitScreensaver() Proxy creation "
+                "failed: %s\n",
+                aError->message);
+            DBusInhibitFailed(/* aFatal */ !IsCancelledGError(aError.get()));
+          });
+}
+
+void WakeLockTopic::DBusUninhibitScreensaver(const char* aName,
+                                             const char* aPath,
+                                             const char* aCall,
+                                             const char* aMethod) {
+  WAKE_LOCK_LOG(
+      "WakeLockTopic::DBusUninhibitScreensaver() mWaitingForDBusInhibit %d "
+      "mWaitingForDBusUninhibit %d request id %d",
+      mWaitingForDBusInhibit, mWaitingForDBusUninhibit,
+      mInhibitRequestID ? *mInhibitRequestID : -1);
+
+  if (mWaitingForDBusUninhibit) {
+    WAKE_LOCK_LOG("  already waiting to uninihibit, return");
+    return;
+  }
+
+  if (mWaitingForDBusInhibit) {
+    WAKE_LOCK_LOG("  cancel inihibit request");
+    g_cancellable_cancel(mCancellable);
+    mWaitingForDBusInhibit = false;
+  }
+
+  if (!mInhibitRequestID.isSome()) {
+    WAKE_LOCK_LOG("  missing inihibit token, quit.");
+    // missing uninhibit token, just quit.
+    return;
+  }
+  mWaitingForDBusUninhibit = true;
+
+  RefPtr<GVariant> variant =
+      dont_AddRef(g_variant_ref_sink(g_variant_new("(u)", *mInhibitRequestID)));
+  nsCOMPtr<nsISerialEventTarget> target = GetCurrentSerialEventTarget();
+  widget::CreateDBusProxyForBus(
+      G_BUS_TYPE_SESSION,
+      GDBusProxyFlags(G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS |
+                      G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES),
+      /* aInterfaceInfo = */ nullptr, aName, aPath, aCall, mCancellable)
+      ->Then(
+          target, __func__,
+          [self = RefPtr{this}, this, args = std::move(variant), target,
+           aMethod](RefPtr<GDBusProxy>&& aProxy) {
+            WAKE_LOCK_LOG(
+                "WakeLockTopic::DBusUninhibitScreensaver() proxy created");
+            DBusProxyCall(aProxy.get(), aMethod, args.get(),
+                          G_DBUS_CALL_FLAGS_NONE, DBUS_TIMEOUT, mCancellable)
+                ->Then(
+                    target, __func__,
+                    [s = RefPtr{this}, this](RefPtr<GVariant>&& aResult) {
+                      DBusUninhibitSucceeded();
+                    },
+                    [s = RefPtr{this}, this,
+                     aMethod](GUniquePtr<GError>&& aError) {
+                      WAKE_LOCK_LOG(
+                          "WakeLockTopic::DBusUninhibitFailed() %s call failed "
+                          ": %s\n",
+                          aMethod, aError->message);
+                      DBusUninhibitFailed();
+                    });
+          },
+          [self = RefPtr{this}, this](GUniquePtr<GError>&& aError) {
+            WAKE_LOCK_LOG(
+                "WakeLockTopic::DBusUninhibitFailed() Proxy creation failed: "
+                "%s\n",
+                aError->message);
+            DBusUninhibitFailed();
+          });
+}
+
+void WakeLockTopic::InhibitFreeDesktopPortal() {
+  WAKE_LOCK_LOG(
+      "WakeLockTopic::InhibitFreeDesktopPortal() mWaitingForDBusInhibit %d "
+      "mWaitingForDBusUninhibit %d",
+      mWaitingForDBusInhibit, mWaitingForDBusUninhibit);
+  if (mWaitingForDBusInhibit) {
+    WAKE_LOCK_LOG("  already waiting to inihibit, return");
+    return;
+  }
+  if (mWaitingForDBusUninhibit) {
+    WAKE_LOCK_LOG("  cancel un-inihibit request");
+    g_cancellable_cancel(mCancellable);
+    mWaitingForDBusUninhibit = false;
+  }
+  mWaitingForDBusInhibit = true;
+
+  CreateDBusProxyForBus(
+      G_BUS_TYPE_SESSION,
+      GDBusProxyFlags(G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS |
+                      G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES),
+      nullptr, FREEDESKTOP_PORTAL_DESKTOP_TARGET,
+      FREEDESKTOP_PORTAL_DESKTOP_OBJECT, FREEDESKTOP_PORTAL_DESKTOP_INTERFACE,
+      mCancellable)
+      ->Then(
+          GetCurrentSerialEventTarget(), __func__,
+          [self = RefPtr{this}, this](RefPtr<GDBusProxy>&& aProxy) {
+            GVariantBuilder b;
+            g_variant_builder_init(&b, G_VARIANT_TYPE_VARDICT);
+            g_variant_builder_add(&b, "{sv}", "reason",
+                                  g_variant_new_string(self->mTopic.get()));
+
+            // From
+            // https://flatpak.github.io/xdg-desktop-portal/docs/#gdbus-org.freedesktop.portal.Inhibit
+            DBusProxyCall(
+                aProxy.get(), "Inhibit",
+                g_variant_new("(sua{sv})", g_get_prgname(),
+                              FREEDESKTOP_PORTAL_DESKTOP_INHIBIT_IDLE_FLAG, &b),
+                G_DBUS_CALL_FLAGS_NONE, DBUS_TIMEOUT, mCancellable)
+                ->Then(
+                    GetCurrentSerialEventTarget(), __func__,
+                    [s = RefPtr{this}, this](RefPtr<GVariant>&& aResult) {
+                      gchar* requestObjectPath = nullptr;
+                      g_variant_get(aResult, "(o)", &requestObjectPath);
+                      if (!requestObjectPath) {
+                        WAKE_LOCK_LOG(
+                            "WakeLockTopic::InhibitFreeDesktopPortal(): Unable "
+                            "to get requestObjectPath\n");
+                        DBusInhibitFailed(/* aFatal */ true);
+                        return;
+                      }
+                      WAKE_LOCK_LOG(
+                          "WakeLockTopic::InhibitFreeDesktopPortal(): "
+                          "inhibited, objpath to unihibit: %s\n",
+                          requestObjectPath);
+                      mRequestObjectPath.Adopt(requestObjectPath);
+                      DBusInhibitSucceeded(0);
+                    },
+                    [s = RefPtr{this}, this](GUniquePtr<GError>&& aError) {
+                      DBusInhibitFailed(
+                          /* aFatal */ !IsCancelledGError(aError.get()));
+                      WAKE_LOCK_LOG(
+                          "Failed to create DBus proxy for "
+                          "org.freedesktop.portal.Desktop: %s\n",
+                          aError->message);
+                    });
+          },
+          [self = RefPtr{this}, this](GUniquePtr<GError>&& aError) {
+            WAKE_LOCK_LOG(
+                "Failed to create DBus proxy for "
+                "org.freedesktop.portal.Desktop: %s\n",
+                aError->message);
+            DBusInhibitFailed(/* aFatal */ !IsCancelledGError(aError.get()));
+          });
+}
+
+void WakeLockTopic::InhibitFreeDesktopScreensaver() {
+  WAKE_LOCK_LOG("InhibitFreeDesktopScreensaver()");
+  DBusInhibitScreensaver(FREEDESKTOP_SCREENSAVER_TARGET,
+                         FREEDESKTOP_SCREENSAVER_OBJECT,
+                         FREEDESKTOP_SCREENSAVER_INTERFACE, "Inhibit",
+                         dont_AddRef(g_variant_ref_sink(g_variant_new(
+                             "(ss)", g_get_prgname(), mTopic.get()))));
+}
+
+void WakeLockTopic::InhibitFreeDesktopPower() {
+  WAKE_LOCK_LOG("InhibitFreeDesktopPower()");
+  DBusInhibitScreensaver(FREEDESKTOP_POWER_TARGET, FREEDESKTOP_POWER_OBJECT,
+                         FREEDESKTOP_POWER_INTERFACE, "Inhibit",
+                         dont_AddRef(g_variant_ref_sink(g_variant_new(
+                             "(ss)", g_get_prgname(), mTopic.get()))));
+}
+
+void WakeLockTopic::InhibitGNOME() {
+  WAKE_LOCK_LOG("InhibitGNOME()");
+  static const uint32_t xid = 0;
+  static const uint32_t flags = (1 << 3);  // Inhibit idle
+  DBusInhibitScreensaver(
+      SESSION_MANAGER_TARGET, SESSION_MANAGER_OBJECT, SESSION_MANAGER_INTERFACE,
+      "Inhibit",
+      dont_AddRef(g_variant_ref_sink(
+          g_variant_new("(susu)", g_get_prgname(), xid, mTopic.get(), flags))));
+}
+
+void WakeLockTopic::UninhibitFreeDesktopPortal() {
+  WAKE_LOCK_LOG(
+      "WakeLockTopic::UninhibitFreeDesktopPortal() mWaitingForDBusInhibit %d "
+      "mWaitingForDBusUninhibit %d object path: %s",
+      mWaitingForDBusInhibit, mWaitingForDBusUninhibit,
+      mRequestObjectPath.get());
+
+  if (mWaitingForDBusUninhibit) {
+    WAKE_LOCK_LOG("  already waiting to uninihibit, return");
+    return;
+  }
+
+  if (mWaitingForDBusInhibit) {
+    WAKE_LOCK_LOG("  cancel inihibit request");
+    g_cancellable_cancel(mCancellable);
+    mWaitingForDBusInhibit = false;
+  }
+  if (mRequestObjectPath.IsEmpty()) {
+    WAKE_LOCK_LOG("UninhibitFreeDesktopPortal() failed: unknown object path\n");
+    return;
+  }
+  mWaitingForDBusUninhibit = true;
+
+  nsCOMPtr<nsISerialEventTarget> target = GetCurrentSerialEventTarget();
+  CreateDBusProxyForBus(
+      G_BUS_TYPE_SESSION,
+      GDBusProxyFlags(G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS |
+                      G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES),
+      nullptr, FREEDESKTOP_PORTAL_DESKTOP_TARGET, mRequestObjectPath.get(),
+      "org.freedesktop.portal.Request", mCancellable)
+      ->Then(
+          target, __func__,
+          [self = RefPtr{this}, target, this](RefPtr<GDBusProxy>&& aProxy) {
+            DBusProxyCall(aProxy.get(), "Close", nullptr,
+                          G_DBUS_CALL_FLAGS_NONE, DBUS_TIMEOUT, mCancellable)
+                ->Then(
+                    target, __func__,
+                    [s = RefPtr{this}, this](RefPtr<GVariant>&& aResult) {
+                      DBusUninhibitSucceeded();
+                      WAKE_LOCK_LOG(
+                          "WakeLockTopic::UninhibitFreeDesktopPortal() Inhibit "
+                          "removed\n");
+                    },
+                    [s = RefPtr{this}, this](GUniquePtr<GError>&& aError) {
+                      DBusUninhibitFailed();
+                      WAKE_LOCK_LOG(
+                          "WakeLockTopic::UninhibitFreeDesktopPortal() "
+                          "Removing inhibit failed: %s\n",
+                          aError->message);
+                    });
+          },
+          [self = RefPtr{this}, this](GUniquePtr<GError>&& aError) {
+            WAKE_LOCK_LOG(
+                "WakeLockTopic::UninhibitFreeDesktopPortal() Proxy creation "
+                "failed: %s\n",
+                aError->message);
+            DBusUninhibitFailed();
+          });
+}
+
+void WakeLockTopic::UninhibitFreeDesktopScreensaver() {
+  WAKE_LOCK_LOG("UninhibitFreeDesktopScreensaver()");
+  DBusUninhibitScreensaver(FREEDESKTOP_SCREENSAVER_TARGET,
+                           FREEDESKTOP_SCREENSAVER_OBJECT,
+                           FREEDESKTOP_SCREENSAVER_INTERFACE, "UnInhibit");
+}
+
+void WakeLockTopic::UninhibitFreeDesktopPower() {
+  WAKE_LOCK_LOG("UninhibitFreeDesktopPower()");
+  DBusUninhibitScreensaver(FREEDESKTOP_POWER_TARGET, FREEDESKTOP_POWER_OBJECT,
+                           FREEDESKTOP_POWER_INTERFACE, "UnInhibit");
+}
+
+void WakeLockTopic::UninhibitGNOME() {
+  WAKE_LOCK_LOG("UninhibitGNOME()");
+  DBusUninhibitScreensaver(SESSION_MANAGER_TARGET, SESSION_MANAGER_OBJECT,
+                           SESSION_MANAGER_INTERFACE, "Uninhibit");
+}
+#endif
+
+#if defined(MOZ_X11)
+// TODO: Merge with Idle service?
+typedef Bool (*_XScreenSaverQueryExtension_fn)(Display* dpy, int* event_base,
+                                               int* error_base);
+typedef Bool (*_XScreenSaverQueryVersion_fn)(Display* dpy, int* major,
+                                             int* minor);
+typedef void (*_XScreenSaverSuspend_fn)(Display* dpy, Bool suspend);
+
+static PRLibrary* sXssLib = nullptr;
+static _XScreenSaverQueryExtension_fn _XSSQueryExtension = nullptr;
+static _XScreenSaverQueryVersion_fn _XSSQueryVersion = nullptr;
+static _XScreenSaverSuspend_fn _XSSSuspend = nullptr;
+
+/* static */
+bool WakeLockTopic::CheckXScreenSaverSupport() {
+  if (!sXssLib) {
+    sXssLib = PR_LoadLibrary("libXss.so.1");
+    if (!sXssLib) {
+      return false;
+    }
+  }
+
+  _XSSQueryExtension = (_XScreenSaverQueryExtension_fn)PR_FindFunctionSymbol(
+      sXssLib, "XScreenSaverQueryExtension");
+  _XSSQueryVersion = (_XScreenSaverQueryVersion_fn)PR_FindFunctionSymbol(
+      sXssLib, "XScreenSaverQueryVersion");
+  _XSSSuspend = (_XScreenSaverSuspend_fn)PR_FindFunctionSymbol(
+      sXssLib, "XScreenSaverSuspend");
+  if (!_XSSQueryExtension || !_XSSQueryVersion || !_XSSSuspend) {
+    return false;
+  }
+
+  GdkDisplay* gDisplay = gdk_display_get_default();
+  if (!GdkIsX11Display(gDisplay)) {
+    return false;
+  }
+  Display* display = GDK_DISPLAY_XDISPLAY(gDisplay);
+
+  int throwaway;
+  if (!_XSSQueryExtension(display, &throwaway, &throwaway)) return false;
+
+  int major, minor;
+  if (!_XSSQueryVersion(display, &major, &minor)) return false;
+  // Needs to be compatible with version 1.1
+  if (major != 1) return false;
+  if (minor < 1) return false;
+
+  WAKE_LOCK_LOG("XScreenSaver supported.");
+  return true;
+}
+
+/* static */
+bool WakeLockTopic::InhibitXScreenSaver(bool inhibit) {
+  WAKE_LOCK_LOG("InhibitXScreenSaver %d", inhibit);
+
+  // Should only be called if CheckXScreenSaverSupport returns true.
+  // There's a couple of safety checks here nonetheless.
+  if (!_XSSSuspend) {
+    return false;
+  }
+  GdkDisplay* gDisplay = gdk_display_get_default();
+  if (!GdkIsX11Display(gDisplay)) {
+    return false;
+  }
+  Display* display = GDK_DISPLAY_XDISPLAY(gDisplay);
+  _XSSSuspend(display, inhibit);
+
+  WAKE_LOCK_LOG("InhibitXScreenSaver %d succeeded", inhibit);
+  mInhibited = inhibit;
+  return true;
+}
+#endif
+
+#if defined(MOZ_WAYLAND)
+/* static */
+bool WakeLockTopic::CheckWaylandIdleInhibitSupport() {
+  nsWaylandDisplay* waylandDisplay = WaylandDisplayGet();
+  return waylandDisplay && waylandDisplay->GetIdleInhibitManager() != nullptr;
+}
+
+bool WakeLockTopic::InhibitWaylandIdle() {
+  WAKE_LOCK_LOG("InhibitWaylandIdle()");
+
+  nsWaylandDisplay* waylandDisplay = WaylandDisplayGet();
+  if (!waylandDisplay) {
+    return false;
+  }
+
+  nsWindow* focusedWindow = nsWindow::GetFocusedWindow();
+  if (!focusedWindow) {
+    return false;
+  }
+
+  UninhibitWaylandIdle();
+
+  MozContainerSurfaceLock lock(focusedWindow->GetMozContainer());
+  struct wl_surface* waylandSurface = lock.GetSurface();
+  if (waylandSurface) {
+    mWaylandInhibitor = zwp_idle_inhibit_manager_v1_create_inhibitor(
+        waylandDisplay->GetIdleInhibitManager(), waylandSurface);
+    mInhibited = true;
+  }
+
+  WAKE_LOCK_LOG("InhibitWaylandIdle() %s",
+                !!mWaylandInhibitor ? "succeeded" : "failed");
+  return !!mWaylandInhibitor;
+}
+
+bool WakeLockTopic::UninhibitWaylandIdle() {
+  WAKE_LOCK_LOG("UninhibitWaylandIdle() mWaylandInhibitor %p",
+                mWaylandInhibitor);
+
+  mInhibited = false;
+  if (!mWaylandInhibitor) {
+    return false;
+  }
+  zwp_idle_inhibitor_v1_destroy(mWaylandInhibitor);
+  mWaylandInhibitor = nullptr;
+  return true;
+}
+#endif
+
+bool WakeLockTopic::SendInhibit() {
+  WAKE_LOCK_LOG("WakeLockTopic::SendInhibit() WakeLockType %s",
+                WakeLockTypeNames[sWakeLockType]);
+  MOZ_ASSERT(sWakeLockType != Initial);
+
+  switch (sWakeLockType) {
+#if defined(MOZ_ENABLE_DBUS)
+    case FreeDesktopPortal:
+      InhibitFreeDesktopPortal();
+      break;
+    case FreeDesktopScreensaver:
+      InhibitFreeDesktopScreensaver();
+      break;
+    case FreeDesktopPower:
+      InhibitFreeDesktopPower();
+      break;
+    case GNOME:
+      InhibitGNOME();
+      break;
+#endif
+#if defined(MOZ_X11)
+    case XScreenSaver:
+      return InhibitXScreenSaver(true);
+#endif
+#if defined(MOZ_WAYLAND)
+    case WaylandIdleInhibit:
+      return InhibitWaylandIdle();
+#endif
+    default:
+      return false;
+  }
+  return true;
+}
+
+bool WakeLockTopic::SendUninhibit() {
+  WAKE_LOCK_LOG("WakeLockTopic::SendUninhibit() WakeLockType %s",
+                WakeLockTypeNames[sWakeLockType]);
+  MOZ_ASSERT(sWakeLockType != Initial);
+  switch (sWakeLockType) {
+#if defined(MOZ_ENABLE_DBUS)
+    case FreeDesktopPortal:
+      UninhibitFreeDesktopPortal();
+      break;
+    case FreeDesktopScreensaver:
+      UninhibitFreeDesktopScreensaver();
+      break;
+    case FreeDesktopPower:
+      UninhibitFreeDesktopPower();
+      break;
+    case GNOME:
+      UninhibitGNOME();
+      break;
+#endif
+#if defined(MOZ_X11)
+    case XScreenSaver:
+      return InhibitXScreenSaver(false);
+#endif
+#if defined(MOZ_WAYLAND)
+    case WaylandIdleInhibit:
+      return UninhibitWaylandIdle();
+#endif
+    default:
+      return false;
+  }
+  return true;
+}
+
+nsresult WakeLockTopic::InhibitScreensaver() {
+  WAKE_LOCK_LOG("WakeLockTopic::InhibitScreensaver() Inhibited %d", mInhibited);
+
+  if (mInhibited) {
+    // Screensaver is inhibited. Nothing to do here.
+    return NS_OK;
+  }
+  mShouldInhibit = true;
+
+  // Iterate through wake lock types in case of failure.
+  while (!SendInhibit() && SwitchToNextWakeLockType()) {
+    ;
+  }
+
+  return (sWakeLockType != Unsupported) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+void WakeLockTopic::Shutdown() {
+  WAKE_LOCK_LOG("WakeLockTopic::Shutdown() state %d", mInhibited);
+#ifdef MOZ_ENABLE_DBUS
+  if (mWaitingForDBusUninhibit) {
+    return;
+  }
+  g_cancellable_cancel(mCancellable);
+#endif
+  if (mInhibited) {
+    UninhibitScreensaver();
+  }
+}
+
+nsresult WakeLockTopic::UninhibitScreensaver() {
+  WAKE_LOCK_LOG("WakeLockTopic::UninhibitScreensaver() Inhibited %d",
+                mInhibited);
+
+  if (!mInhibited) {
+    // Screensaver isn't inhibited. Nothing to do here.
+    return NS_OK;
+  }
+  mShouldInhibit = false;
+
+  // Don't switch wake lock type in case of failure.
+  // We need to use the same lock/unlock type.
+  return SendUninhibit() ? NS_OK : NS_ERROR_FAILURE;
+}
+
+bool WakeLockTopic::IsWakeLockTypeAvailable(int aWakeLockType) {
+  switch (aWakeLockType) {
+#if defined(MOZ_ENABLE_DBUS)
+    case FreeDesktopPortal:
+    case FreeDesktopScreensaver:
+    case FreeDesktopPower:
+    case GNOME:
+      return true;
+#endif
+#if defined(MOZ_X11)
+    case XScreenSaver:
+      if (!GdkIsX11Display()) {
+        return false;
+      }
+      if (!CheckXScreenSaverSupport()) {
+        WAKE_LOCK_LOG("  XScreenSaverSupport is missing!");
+        return false;
+      }
+      return true;
+#endif
+#if defined(MOZ_WAYLAND)
+    case WaylandIdleInhibit:
+      if (!GdkIsWaylandDisplay()) {
+        return false;
+      }
+      if (!CheckWaylandIdleInhibitSupport()) {
+        WAKE_LOCK_LOG("  WaylandIdleInhibitSupport is missing!");
+        return false;
+      }
+      return true;
+#endif
+    default:
+      return false;
+  }
+}
+
+bool WakeLockTopic::SwitchToNextWakeLockType() {
+  WAKE_LOCK_LOG("WakeLockTopic::SwitchToNextWakeLockType() WakeLockType %s",
+                WakeLockTypeNames[sWakeLockType]);
+
+  if (sWakeLockType == Unsupported) {
+    return false;
+  }
+
+#ifdef MOZ_LOGGING
+  auto printWakeLocktype = MakeScopeExit([&] {
+    WAKE_LOCK_LOG("  switched to WakeLockType %s",
+                  WakeLockTypeNames[sWakeLockType]);
+  });
+#endif
+
+#if defined(MOZ_ENABLE_DBUS)
+  if (IsDBusWakeLock(sWakeLockType)) {
+    // We're switching out of DBus wakelock - clear our recent DBus states.
+    mWaitingForDBusInhibit = false;
+    mWaitingForDBusUninhibit = false;
+    mInhibited = false;
+    ClearDBusInhibitToken();
+  }
+#endif
+
+  while (sWakeLockType != Unsupported) {
+    sWakeLockType++;
+    if (IsWakeLockTypeAvailable(sWakeLockType)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+WakeLockListener::WakeLockListener() = default;
+
+WakeLockListener::~WakeLockListener() {
+  for (const auto& topic : mTopics.Values()) {
+    topic->Shutdown();
+  }
+}
+
+nsresult WakeLockListener::Callback(const nsAString& topic,
+                                    const nsAString& state) {
+  if (!topic.Equals(u"screen"_ns) && !topic.Equals(u"video-playing"_ns) &&
+      !topic.Equals(u"autoscroll"_ns)) {
+    return NS_OK;
+  }
+
+  RefPtr<WakeLockTopic> topicLock = mTopics.LookupOrInsertWith(
+      topic, [&] { return MakeRefPtr<WakeLockTopic>(topic); });
+
+  // Treat "locked-background" the same as "unlocked" on desktop linux.
+  bool shouldLock = state.EqualsLiteral("locked-foreground");
+  WAKE_LOCK_LOG("WakeLockListener topic %s state %s request lock %d",
+                NS_ConvertUTF16toUTF8(topic).get(),
+                NS_ConvertUTF16toUTF8(state).get(), shouldLock);
+
+  return shouldLock ? topicLock->InhibitScreensaver()
+                    : topicLock->UninhibitScreensaver();
+}
diff --git a/widget/gtk/WakeLockListener.h b/widget/gtk/WakeLockListener.h
new file mode 100644
index 0000000000..1c587d2302
--- /dev/null
+++ b/widget/gtk/WakeLockListener.h
@@ -0,0 +1,38 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __WakeLockListener_h__
+#define __WakeLockListener_h__
+
+#include "nsHashKeys.h"
+#include "nsRefPtrHashtable.h"
+
+#include "nsIDOMWakeLockListener.h"
+
+class WakeLockTopic;
+
+/**
+ * Receives WakeLock events and simply passes it on to the right WakeLockTopic
+ * to inhibit the screensaver.
+ */
+class WakeLockListener final : public nsIDOMMozWakeLockListener {
+ public:
+  NS_DECL_ISUPPORTS;
+
+  nsresult Callback(const nsAString& topic, const nsAString& state) override;
+
+  WakeLockListener();
+
+ private:
+  ~WakeLockListener();
+
+  // Map of topic names to |WakeLockTopic|s.
+  // We assume a small, finite-sized set of topics.
+  nsRefPtrHashtable<nsStringHashKey, WakeLockTopic> mTopics;
+};
+
+#endif  // __WakeLockListener_h__
diff --git a/widget/gtk/WaylandBuffer.cpp b/widget/gtk/WaylandBuffer.cpp
new file mode 100644
index 0000000000..f3fc409362
--- /dev/null
+++ b/widget/gtk/WaylandBuffer.cpp
@@ -0,0 +1,224 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WaylandBuffer.h"
+
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include "gfx2DGlue.h"
+#include "gfxPlatform.h"
+#include "mozilla/WidgetUtilsGtk.h"
+#include "mozilla/gfx/Tools.h"
+#include "nsGtkUtils.h"
+#include "nsPrintfCString.h"
+#include "prenv.h"  // For PR_GetEnv
+
+#ifdef MOZ_LOGGING
+#  include "mozilla/Logging.h"
+#  include "mozilla/ScopeExit.h"
+#  include "Units.h"
+extern mozilla::LazyLogModule gWidgetWaylandLog;
+#  define LOGWAYLAND(...) \
+    MOZ_LOG(gWidgetWaylandLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#else
+#  define LOGWAYLAND(...)
+#endif /* MOZ_LOGGING */
+
+using namespace mozilla::gl;
+
+namespace mozilla::widget {
+
+#define BUFFER_BPP 4
+gfx::SurfaceFormat WaylandBuffer::mFormat = gfx::SurfaceFormat::B8G8R8A8;
+
+#ifdef MOZ_LOGGING
+int WaylandBufferSHM::mDumpSerial =
+    PR_GetEnv("MOZ_WAYLAND_DUMP_WL_BUFFERS") ? 1 : 0;
+char* WaylandBufferSHM::mDumpDir = PR_GetEnv("MOZ_WAYLAND_DUMP_DIR");
+#endif
+
+/* static */
+RefPtr<WaylandShmPool> WaylandShmPool::Create(nsWaylandDisplay* aWaylandDisplay,
+                                              int aSize) {
+  if (!aWaylandDisplay->GetShm()) {
+    NS_WARNING("WaylandShmPool: Missing Wayland shm interface!");
+    return nullptr;
+  }
+
+  RefPtr<WaylandShmPool> shmPool = new WaylandShmPool();
+
+  shmPool->mShm = MakeUnique<base::SharedMemory>();
+  if (!shmPool->mShm->Create(aSize)) {
+    NS_WARNING("WaylandShmPool: Unable to allocate shared memory!");
+    return nullptr;
+  }
+
+  shmPool->mSize = aSize;
+  shmPool->mShmPool = wl_shm_create_pool(
+      aWaylandDisplay->GetShm(), shmPool->mShm->CloneHandle().get(), aSize);
+  if (!shmPool->mShmPool) {
+    NS_WARNING("WaylandShmPool: Unable to allocate shared memory pool!");
+    return nullptr;
+  }
+
+  return shmPool;
+}
+
+void* WaylandShmPool::GetImageData() {
+  if (mImageData) {
+    return mImageData;
+  }
+  if (!mShm->Map(mSize)) {
+    NS_WARNING("WaylandShmPool: Failed to map Shm!");
+    return nullptr;
+  }
+  mImageData = mShm->memory();
+  return mImageData;
+}
+
+WaylandShmPool::~WaylandShmPool() {
+  MozClearPointer(mShmPool, wl_shm_pool_destroy);
+}
+
+static const struct wl_buffer_listener sBufferListenerWaylandBuffer = {
+    WaylandBuffer::BufferReleaseCallbackHandler};
+
+WaylandBuffer::WaylandBuffer(const LayoutDeviceIntSize& aSize) : mSize(aSize) {}
+
+void WaylandBuffer::AttachAndCommit(wl_surface* aSurface) {
+  LOGWAYLAND(
+      "WaylandBuffer::AttachAndCommit [%p] wl_surface %p ID %d wl_buffer "
+      "%p ID %d\n",
+      (void*)this, (void*)aSurface,
+      aSurface ? wl_proxy_get_id((struct wl_proxy*)aSurface) : -1,
+      (void*)GetWlBuffer(),
+      GetWlBuffer() ? wl_proxy_get_id((struct wl_proxy*)GetWlBuffer()) : -1);
+
+  wl_buffer* buffer = GetWlBuffer();
+  if (buffer) {
+    mAttached = true;
+    wl_surface_attach(aSurface, buffer, 0, 0);
+    wl_surface_commit(aSurface);
+  }
+}
+
+void WaylandBuffer::BufferReleaseCallbackHandler(wl_buffer* aBuffer) {
+  mAttached = false;
+
+  if (mBufferReleaseFunc) {
+    mBufferReleaseFunc(mBufferReleaseData, aBuffer);
+  }
+}
+
+void WaylandBuffer::BufferReleaseCallbackHandler(void* aData,
+                                                 wl_buffer* aBuffer) {
+  auto* buffer = reinterpret_cast<WaylandBuffer*>(aData);
+  buffer->BufferReleaseCallbackHandler(aBuffer);
+}
+
+/* static */
+RefPtr<WaylandBufferSHM> WaylandBufferSHM::Create(
+    const LayoutDeviceIntSize& aSize) {
+  RefPtr<WaylandBufferSHM> buffer = new WaylandBufferSHM(aSize);
+  nsWaylandDisplay* waylandDisplay = WaylandDisplayGet();
+
+  int size = aSize.width * aSize.height * BUFFER_BPP;
+  buffer->mShmPool = WaylandShmPool::Create(waylandDisplay, size);
+  if (!buffer->mShmPool) {
+    return nullptr;
+  }
+
+  buffer->mWLBuffer = wl_shm_pool_create_buffer(
+      buffer->mShmPool->GetShmPool(), 0, aSize.width, aSize.height,
+      aSize.width * BUFFER_BPP, WL_SHM_FORMAT_ARGB8888);
+  if (!buffer->mWLBuffer) {
+    return nullptr;
+  }
+
+  wl_buffer_add_listener(buffer->GetWlBuffer(), &sBufferListenerWaylandBuffer,
+                         buffer.get());
+
+  LOGWAYLAND("WaylandBufferSHM Created [%p] WaylandDisplay [%p]\n",
+             buffer.get(), waylandDisplay);
+
+  return buffer;
+}
+
+WaylandBufferSHM::WaylandBufferSHM(const LayoutDeviceIntSize& aSize)
+    : WaylandBuffer(aSize) {}
+
+WaylandBufferSHM::~WaylandBufferSHM() {
+  MozClearPointer(mWLBuffer, wl_buffer_destroy);
+}
+
+already_AddRefed<gfx::DrawTarget> WaylandBufferSHM::Lock() {
+  return gfxPlatform::CreateDrawTargetForData(
+      static_cast<unsigned char*>(mShmPool->GetImageData()),
+      mSize.ToUnknownSize(), BUFFER_BPP * mSize.width, GetSurfaceFormat());
+}
+
+void WaylandBufferSHM::Clear() {
+  memset(mShmPool->GetImageData(), 0, mSize.height * mSize.width * BUFFER_BPP);
+}
+
+#ifdef MOZ_LOGGING
+void WaylandBufferSHM::DumpToFile(const char* aHint) {
+  if (!mDumpSerial) {
+    return;
+  }
+
+  cairo_surface_t* surface = nullptr;
+  auto unmap = MakeScopeExit([&] {
+    if (surface) {
+      cairo_surface_destroy(surface);
+    }
+  });
+  surface = cairo_image_surface_create_for_data(
+      (unsigned char*)mShmPool->GetImageData(), CAIRO_FORMAT_ARGB32,
+      mSize.width, mSize.height, BUFFER_BPP * mSize.width);
+  if (cairo_surface_status(surface) == CAIRO_STATUS_SUCCESS) {
+    nsCString filename;
+    if (mDumpDir) {
+      filename.Append(mDumpDir);
+      filename.Append('/');
+    }
+    filename.Append(
+        nsPrintfCString("firefox-wl-buffer-%.5d-%s.png", mDumpSerial++, aHint));
+    cairo_surface_write_to_png(surface, filename.get());
+    LOGWAYLAND("Dumped wl_buffer to %s\n", filename.get());
+  }
+}
+#endif
+
+/* static */
+RefPtr<WaylandBufferDMABUF> WaylandBufferDMABUF::Create(
+    const LayoutDeviceIntSize& aSize, GLContext* aGL) {
+  RefPtr<WaylandBufferDMABUF> buffer = new WaylandBufferDMABUF(aSize);
+
+  const auto flags =
+      static_cast<DMABufSurfaceFlags>(DMABUF_TEXTURE | DMABUF_ALPHA);
+  buffer->mDMABufSurface =
+      DMABufSurfaceRGBA::CreateDMABufSurface(aSize.width, aSize.height, flags);
+  if (!buffer->mDMABufSurface || !buffer->mDMABufSurface->CreateTexture(aGL)) {
+    return nullptr;
+  }
+
+  if (!buffer->mDMABufSurface->CreateWlBuffer()) {
+    return nullptr;
+  }
+
+  wl_buffer_add_listener(buffer->GetWlBuffer(), &sBufferListenerWaylandBuffer,
+                         buffer.get());
+
+  return buffer;
+}
+
+WaylandBufferDMABUF::WaylandBufferDMABUF(const LayoutDeviceIntSize& aSize)
+    : WaylandBuffer(aSize) {}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/WaylandBuffer.h b/widget/gtk/WaylandBuffer.h
new file mode 100644
index 0000000000..34bdb87ff5
--- /dev/null
+++ b/widget/gtk/WaylandBuffer.h
@@ -0,0 +1,140 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _MOZILLA_WIDGET_GTK_WAYLAND_BUFFER_H
+#define _MOZILLA_WIDGET_GTK_WAYLAND_BUFFER_H
+
+#include "DMABufSurface.h"
+#include "GLContext.h"
+#include "MozFramebuffer.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Types.h"
+#include "mozilla/Mutex.h"
+#include "nsTArray.h"
+#include "nsWaylandDisplay.h"
+#include "base/shared_memory.h"
+
+namespace mozilla::widget {
+
+// Allocates and owns shared memory for Wayland drawing surface
+class WaylandShmPool {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WaylandShmPool);
+
+  static RefPtr<WaylandShmPool> Create(nsWaylandDisplay* aWaylandDisplay,
+                                       int aSize);
+
+  wl_shm_pool* GetShmPool() { return mShmPool; };
+  void* GetImageData();
+
+ private:
+  WaylandShmPool() = default;
+  ~WaylandShmPool();
+
+  wl_shm_pool* mShmPool = nullptr;
+  void* mImageData = nullptr;
+  UniquePtr<base::SharedMemory> mShm;
+  int mSize = 0;
+};
+
+class WaylandBuffer {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WaylandBuffer);
+
+  void AttachAndCommit(wl_surface* aSurface);
+  virtual wl_buffer* GetWlBuffer() = 0;
+  virtual already_AddRefed<gfx::DrawTarget> Lock() { return nullptr; };
+  virtual void* GetImageData() { return nullptr; }
+  virtual GLuint GetTexture() { return 0; }
+  virtual void DestroyGLResources(){};
+
+  LayoutDeviceIntSize GetSize() { return mSize; };
+  bool IsMatchingSize(const LayoutDeviceIntSize& aSize) {
+    return aSize == mSize;
+  }
+  bool IsAttached() { return mAttached; }
+  static gfx::SurfaceFormat GetSurfaceFormat() { return mFormat; }
+
+  static void BufferReleaseCallbackHandler(void* aData, wl_buffer* aBuffer);
+  void SetBufferReleaseFunc(void (*aBufferReleaseFunc)(void* aData,
+                                                       wl_buffer* aBuffer)) {
+    mBufferReleaseFunc = aBufferReleaseFunc;
+  }
+  void SetBufferReleaseData(void* aBufferReleaseData) {
+    mBufferReleaseData = aBufferReleaseData;
+  }
+
+ protected:
+  explicit WaylandBuffer(const LayoutDeviceIntSize& aSize);
+  virtual ~WaylandBuffer() = default;
+
+  void BufferReleaseCallbackHandler(wl_buffer* aBuffer);
+
+  LayoutDeviceIntSize mSize;
+  bool mAttached = false;
+  void (*mBufferReleaseFunc)(void* aData, wl_buffer* aBuffer) = nullptr;
+  void* mBufferReleaseData = nullptr;
+  static gfx::SurfaceFormat mFormat;
+};
+
+// Holds actual graphics data for wl_surface
+class WaylandBufferSHM final : public WaylandBuffer {
+ public:
+  static RefPtr<WaylandBufferSHM> Create(const LayoutDeviceIntSize& aSize);
+
+  wl_buffer* GetWlBuffer() override { return mWLBuffer; };
+  already_AddRefed<gfx::DrawTarget> Lock() override;
+  void* GetImageData() override { return mShmPool->GetImageData(); }
+
+  void Clear();
+  size_t GetBufferAge() { return mBufferAge; };
+  RefPtr<WaylandShmPool> GetShmPool() { return mShmPool; }
+
+  void IncrementBufferAge() { mBufferAge++; };
+  void ResetBufferAge() { mBufferAge = 0; };
+
+#ifdef MOZ_LOGGING
+  void DumpToFile(const char* aHint);
+#endif
+
+ private:
+  explicit WaylandBufferSHM(const LayoutDeviceIntSize& aSize);
+  ~WaylandBufferSHM() override;
+
+  // WaylandShmPoolMB provides actual shared memory we draw into
+  RefPtr<WaylandShmPool> mShmPool;
+
+  // wl_buffer is a wayland object that encapsulates the shared memory
+  // and passes it to wayland compositor by wl_surface object.
+  wl_buffer* mWLBuffer = nullptr;
+
+  size_t mBufferAge = 0;
+
+#ifdef MOZ_LOGGING
+  static int mDumpSerial;
+  static char* mDumpDir;
+#endif
+};
+
+class WaylandBufferDMABUF final : public WaylandBuffer {
+ public:
+  static RefPtr<WaylandBufferDMABUF> Create(const LayoutDeviceIntSize& aSize,
+                                            gl::GLContext* aGL);
+
+  wl_buffer* GetWlBuffer() override { return mDMABufSurface->GetWlBuffer(); };
+  GLuint GetTexture() override { return mDMABufSurface->GetTexture(); };
+  void DestroyGLResources() override { mDMABufSurface->ReleaseTextures(); };
+
+ private:
+  explicit WaylandBufferDMABUF(const LayoutDeviceIntSize& aSize);
+  ~WaylandBufferDMABUF() = default;
+
+  RefPtr<DMABufSurfaceRGBA> mDMABufSurface;
+};
+
+}  // namespace mozilla::widget
+
+#endif  // _MOZILLA_WIDGET_GTK_WAYLAND_BUFFER_H
diff --git a/widget/gtk/WaylandVsyncSource.cpp b/widget/gtk/WaylandVsyncSource.cpp
new file mode 100644
index 0000000000..e5bca04837
--- /dev/null
+++ b/widget/gtk/WaylandVsyncSource.cpp
@@ -0,0 +1,431 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifdef MOZ_WAYLAND
+
+#  include "WaylandVsyncSource.h"
+#  include "mozilla/UniquePtr.h"
+#  include "nsThreadUtils.h"
+#  include "nsISupportsImpl.h"
+#  include "MainThreadUtils.h"
+#  include "mozilla/ScopeExit.h"
+#  include "nsGtkUtils.h"
+#  include "mozilla/StaticPrefs_layout.h"
+#  include "mozilla/StaticPrefs_widget.h"
+#  include "nsWindow.h"
+
+#  include <gdk/gdkwayland.h>
+
+#  ifdef MOZ_LOGGING
+#    include "mozilla/Logging.h"
+#    include "nsTArray.h"
+#    include "Units.h"
+extern mozilla::LazyLogModule gWidgetVsync;
+#    undef LOG
+#    define LOG(str, ...)                             \
+      MOZ_LOG(gWidgetVsync, mozilla::LogLevel::Debug, \
+              ("[nsWindow %p]: " str, GetWindowForLogging(), ##__VA_ARGS__))
+#  else
+#    define LOG(...)
+#  endif /* MOZ_LOGGING */
+
+using namespace mozilla::widget;
+
+namespace mozilla {
+
+static void WaylandVsyncSourceCallbackHandler(void* aData,
+                                              struct wl_callback* aCallback,
+                                              uint32_t aTime) {
+  RefPtr context = static_cast<WaylandVsyncSource*>(aData);
+  context->FrameCallback(aCallback, aTime);
+}
+
+static const struct wl_callback_listener WaylandVsyncSourceCallbackListener = {
+    WaylandVsyncSourceCallbackHandler};
+
+static void NativeLayerRootWaylandVsyncCallback(void* aData, uint32_t aTime) {
+  RefPtr context = static_cast<WaylandVsyncSource*>(aData);
+  context->FrameCallback(nullptr, aTime);
+}
+
+static float GetFPS(TimeDuration aVsyncRate) {
+  return 1000.0f / float(aVsyncRate.ToMilliseconds());
+}
+
+static nsTArray<WaylandVsyncSource*> gWaylandVsyncSources;
+
+Maybe<TimeDuration> WaylandVsyncSource::GetFastestVsyncRate() {
+  Maybe<TimeDuration> retVal;
+  for (auto* source : gWaylandVsyncSources) {
+    auto rate = source->GetVsyncRateIfEnabled();
+    if (!rate) {
+      continue;
+    }
+    if (!retVal.isSome()) {
+      retVal.emplace(*rate);
+    } else if (*rate < *retVal) {
+      retVal.ref() = *rate;
+    }
+  }
+
+  return retVal;
+}
+
+WaylandVsyncSource::WaylandVsyncSource(nsWindow* aWindow)
+    : mMutex("WaylandVsyncSource"),
+      mVsyncRate(TimeDuration::FromMilliseconds(1000.0 / 60.0)),
+      mLastVsyncTimeStamp(TimeStamp::Now()),
+      mWindow(aWindow),
+      mIdleTimeout(1000 / StaticPrefs::layout_throttled_frame_rate()) {
+  MOZ_ASSERT(NS_IsMainThread());
+  gWaylandVsyncSources.AppendElement(this);
+}
+
+WaylandVsyncSource::~WaylandVsyncSource() {
+  gWaylandVsyncSources.RemoveElement(this);
+}
+
+void WaylandVsyncSource::MaybeUpdateSource(MozContainer* aContainer) {
+  MutexAutoLock lock(mMutex);
+
+  LOG("WaylandVsyncSource::MaybeUpdateSource fps %f", GetFPS(mVsyncRate));
+
+  if (aContainer == mContainer) {
+    LOG("  mContainer is the same, quit.");
+    return;
+  }
+
+  mNativeLayerRoot = nullptr;
+  mContainer = aContainer;
+
+  if (mMonitorEnabled) {
+    LOG("  monitor enabled, ask for Refresh()");
+    mCallbackRequested = false;
+    Refresh(lock);
+  }
+}
+
+void WaylandVsyncSource::MaybeUpdateSource(
+    const RefPtr<NativeLayerRootWayland>& aNativeLayerRoot) {
+  MutexAutoLock lock(mMutex);
+
+  LOG("WaylandVsyncSource::MaybeUpdateSource aNativeLayerRoot fps %f",
+      GetFPS(mVsyncRate));
+
+  if (aNativeLayerRoot == mNativeLayerRoot) {
+    LOG("  mNativeLayerRoot is the same, quit.");
+    return;
+  }
+
+  mNativeLayerRoot = aNativeLayerRoot;
+  mContainer = nullptr;
+
+  if (mMonitorEnabled) {
+    LOG("  monitor enabled, ask for Refresh()");
+    mCallbackRequested = false;
+    Refresh(lock);
+  }
+}
+
+void WaylandVsyncSource::Refresh(const MutexAutoLock& aProofOfLock) {
+  mMutex.AssertCurrentThreadOwns();
+
+  LOG("WaylandVsyncSource::Refresh fps %f\n", GetFPS(mVsyncRate));
+
+  if (!(mContainer || mNativeLayerRoot) || !mMonitorEnabled || !mVsyncEnabled ||
+      mCallbackRequested) {
+    // We don't need to do anything because:
+    // * We are unwanted by our widget or monitor, or
+    // * The last frame callback hasn't yet run to see that it had been shut
+    //   down, so we can reuse it after having set mVsyncEnabled to true.
+    LOG("  quit mContainer %d mNativeLayerRoot %d mMonitorEnabled %d "
+        "mVsyncEnabled %d mCallbackRequested %d",
+        !!mContainer, !!mNativeLayerRoot, mMonitorEnabled, mVsyncEnabled,
+        !!mCallbackRequested);
+    return;
+  }
+
+  if (mContainer) {
+    MozContainerSurfaceLock lock(mContainer);
+    struct wl_surface* surface = lock.GetSurface();
+    LOG("  refresh from mContainer, wl_surface %p", surface);
+    if (!surface) {
+      LOG("  we're missing wl_surface, register Refresh() callback");
+      // The surface hasn't been created yet. Try again when the surface is
+      // ready.
+      RefPtr<WaylandVsyncSource> self(this);
+      moz_container_wayland_add_initial_draw_callback_locked(
+          mContainer, [self]() -> void {
+            MutexAutoLock lock(self->mMutex);
+            self->Refresh(lock);
+          });
+      return;
+    }
+  }
+
+  // Vsync is enabled, but we don't have a callback configured. Set one up so
+  // we can get to work.
+  SetupFrameCallback(aProofOfLock);
+  const TimeStamp lastVSync = TimeStamp::Now();
+  mLastVsyncTimeStamp = lastVSync;
+  TimeStamp outputTimestamp = mLastVsyncTimeStamp + mVsyncRate;
+
+  {
+    MutexAutoUnlock unlock(mMutex);
+    NotifyVsync(lastVSync, outputTimestamp);
+  }
+}
+
+void WaylandVsyncSource::EnableMonitor() {
+  LOG("WaylandVsyncSource::EnableMonitor");
+  MutexAutoLock lock(mMutex);
+  if (mMonitorEnabled) {
+    return;
+  }
+  mMonitorEnabled = true;
+  Refresh(lock);
+}
+
+void WaylandVsyncSource::DisableMonitor() {
+  LOG("WaylandVsyncSource::DisableMonitor");
+  MutexAutoLock lock(mMutex);
+  if (!mMonitorEnabled) {
+    return;
+  }
+  mMonitorEnabled = false;
+  mCallbackRequested = false;
+}
+
+void WaylandVsyncSource::SetupFrameCallback(const MutexAutoLock& aProofOfLock) {
+  mMutex.AssertCurrentThreadOwns();
+  MOZ_ASSERT(!mCallbackRequested);
+
+  LOG("WaylandVsyncSource::SetupFrameCallback");
+
+  if (mNativeLayerRoot) {
+    LOG("  use mNativeLayerRoot");
+    mNativeLayerRoot->RequestFrameCallback(&NativeLayerRootWaylandVsyncCallback,
+                                           this);
+  } else {
+    MozContainerSurfaceLock lock(mContainer);
+    struct wl_surface* surface = lock.GetSurface();
+    LOG("  use mContainer, wl_surface %p", surface);
+    if (!surface) {
+      // We don't have a surface, either due to being called before it was made
+      // available in the mozcontainer, or after it was destroyed. We're all
+      // done regardless.
+      LOG("  missing wl_surface, quit.");
+      return;
+    }
+
+    LOG("  register frame callback");
+    MozClearPointer(mCallback, wl_callback_destroy);
+    mCallback = wl_surface_frame(surface);
+    wl_callback_add_listener(mCallback, &WaylandVsyncSourceCallbackListener,
+                             this);
+    wl_surface_commit(surface);
+    wl_display_flush(WaylandDisplayGet()->GetDisplay());
+
+    if (!mIdleTimerID) {
+      mIdleTimerID = g_timeout_add(
+          mIdleTimeout,
+          [](void* data) -> gint {
+            RefPtr vsync = static_cast<WaylandVsyncSource*>(data);
+            if (vsync->IdleCallback()) {
+              // We want to fire again, so don't clear mIdleTimerID
+              return G_SOURCE_CONTINUE;
+            }
+            // No need for g_source_remove, caller does it for us.
+            vsync->mIdleTimerID = 0;
+            return G_SOURCE_REMOVE;
+          },
+          this);
+    }
+  }
+
+  mCallbackRequested = true;
+}
+
+bool WaylandVsyncSource::IdleCallback() {
+  LOG("WaylandVsyncSource::IdleCallback");
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+
+  RefPtr<nsWindow> window;
+  TimeStamp lastVSync;
+  TimeStamp outputTimestamp;
+  {
+    MutexAutoLock lock(mMutex);
+
+    if (!mVsyncEnabled || !mMonitorEnabled) {
+      // We are unwanted by either our creator or our consumer, so we just stop
+      // here without setting up a new frame callback.
+      LOG("  quit, mVsyncEnabled %d mMonitorEnabled %d", mVsyncEnabled,
+          mMonitorEnabled);
+      return false;
+    }
+
+    const auto now = TimeStamp::Now();
+    const auto timeSinceLastVSync = now - mLastVsyncTimeStamp;
+    if (timeSinceLastVSync.ToMilliseconds() < mIdleTimeout) {
+      // We're not idle, we want to fire the timer again.
+      return true;
+    }
+
+    LOG("  fire idle vsync");
+    CalculateVsyncRate(lock, now);
+    mLastVsyncTimeStamp = lastVSync = now;
+
+    outputTimestamp = mLastVsyncTimeStamp + mVsyncRate;
+    window = mWindow;
+  }
+
+  // This could disable vsync.
+  window->NotifyOcclusionState(OcclusionState::OCCLUDED);
+
+  if (window->IsDestroyed()) {
+    return false;
+  }
+  // Make sure to fire vsync now even if we get disabled afterwards.
+  // This gives an opportunity to clean up after the visibility state change.
+  // FIXME: Do we really need to do this?
+  NotifyVsync(lastVSync, outputTimestamp);
+  return StaticPrefs::widget_wayland_vsync_keep_firing_at_idle();
+}
+
+void WaylandVsyncSource::FrameCallback(wl_callback* aCallback, uint32_t aTime) {
+  LOG("WaylandVsyncSource::FrameCallback");
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+
+  {
+    // This might enable vsync.
+    RefPtr window = mWindow;
+    window->NotifyOcclusionState(OcclusionState::VISIBLE);
+    // NotifyOcclusionState can destroy us.
+    if (window->IsDestroyed()) {
+      return;
+    }
+  }
+
+  MutexAutoLock lock(mMutex);
+  mCallbackRequested = false;
+
+  // NotifyOcclusionState() can clear and create new mCallback by
+  // EnableVsync()/Refresh(). So don't delete newly created frame callback.
+  if (aCallback && aCallback == mCallback) {
+    MozClearPointer(mCallback, wl_callback_destroy);
+  }
+
+  if (!mVsyncEnabled || !mMonitorEnabled) {
+    // We are unwanted by either our creator or our consumer, so we just stop
+    // here without setting up a new frame callback.
+    LOG("  quit, mVsyncEnabled %d mMonitorEnabled %d", mVsyncEnabled,
+        mMonitorEnabled);
+    return;
+  }
+
+  // Configure our next frame callback.
+  SetupFrameCallback(lock);
+
+  int64_t tick = BaseTimeDurationPlatformUtils::TicksFromMilliseconds(aTime);
+  const auto callbackTimeStamp = TimeStamp::FromSystemTime(tick);
+  const auto now = TimeStamp::Now();
+
+  // If the callback timestamp is close enough to our timestamp, use it,
+  // otherwise use the current time.
+  const TimeStamp& vsyncTimestamp =
+      std::abs((now - callbackTimeStamp).ToMilliseconds()) < 50.0
+          ? callbackTimeStamp
+          : now;
+
+  CalculateVsyncRate(lock, vsyncTimestamp);
+  mLastVsyncTimeStamp = vsyncTimestamp;
+  const TimeStamp outputTimestamp = vsyncTimestamp + mVsyncRate;
+
+  {
+    MutexAutoUnlock unlock(mMutex);
+    NotifyVsync(vsyncTimestamp, outputTimestamp);
+  }
+}
+
+TimeDuration WaylandVsyncSource::GetVsyncRate() {
+  MutexAutoLock lock(mMutex);
+  return mVsyncRate;
+}
+
+Maybe<TimeDuration> WaylandVsyncSource::GetVsyncRateIfEnabled() {
+  MutexAutoLock lock(mMutex);
+  if (!mVsyncEnabled) {
+    return Nothing();
+  }
+  return Some(mVsyncRate);
+}
+
+void WaylandVsyncSource::CalculateVsyncRate(const MutexAutoLock& aProofOfLock,
+                                            TimeStamp aVsyncTimestamp) {
+  mMutex.AssertCurrentThreadOwns();
+
+  double duration = (aVsyncTimestamp - mLastVsyncTimeStamp).ToMilliseconds();
+  double curVsyncRate = mVsyncRate.ToMilliseconds();
+
+  LOG("WaylandVsyncSource::CalculateVsyncRate start fps %f\n",
+      GetFPS(mVsyncRate));
+
+  double correction;
+  if (duration > curVsyncRate) {
+    correction = fmin(curVsyncRate, (duration - curVsyncRate) / 10);
+    mVsyncRate += TimeDuration::FromMilliseconds(correction);
+  } else {
+    correction = fmin(curVsyncRate / 2, (curVsyncRate - duration) / 10);
+    mVsyncRate -= TimeDuration::FromMilliseconds(correction);
+  }
+
+  LOG("  new fps %f correction %f\n", GetFPS(mVsyncRate), correction);
+}
+
+void WaylandVsyncSource::EnableVsync() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  MutexAutoLock lock(mMutex);
+
+  LOG("WaylandVsyncSource::EnableVsync fps %f\n", GetFPS(mVsyncRate));
+  if (mVsyncEnabled || mIsShutdown) {
+    LOG("  early quit");
+    return;
+  }
+  mVsyncEnabled = true;
+  Refresh(lock);
+}
+
+void WaylandVsyncSource::DisableVsync() {
+  MutexAutoLock lock(mMutex);
+
+  LOG("WaylandVsyncSource::DisableVsync fps %f\n", GetFPS(mVsyncRate));
+  mVsyncEnabled = false;
+  mCallbackRequested = false;
+}
+
+bool WaylandVsyncSource::IsVsyncEnabled() {
+  MutexAutoLock lock(mMutex);
+  return mVsyncEnabled;
+}
+
+void WaylandVsyncSource::Shutdown() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MutexAutoLock lock(mMutex);
+
+  LOG("WaylandVsyncSource::Shutdown fps %f\n", GetFPS(mVsyncRate));
+  mContainer = nullptr;
+  mNativeLayerRoot = nullptr;
+  mIsShutdown = true;
+  mVsyncEnabled = false;
+  mCallbackRequested = false;
+  MozClearHandleID(mIdleTimerID, g_source_remove);
+  MozClearPointer(mCallback, wl_callback_destroy);
+}
+
+}  // namespace mozilla
+
+#endif  // MOZ_WAYLAND
diff --git a/widget/gtk/WaylandVsyncSource.h b/widget/gtk/WaylandVsyncSource.h
new file mode 100644
index 0000000000..78fe72e445
--- /dev/null
+++ b/widget/gtk/WaylandVsyncSource.h
@@ -0,0 +1,99 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _WaylandVsyncSource_h_
+#define _WaylandVsyncSource_h_
+
+#include "base/thread.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/layers/NativeLayerWayland.h"
+#include "MozContainer.h"
+#include "nsWaylandDisplay.h"
+#include "VsyncSource.h"
+
+namespace mozilla {
+
+using layers::NativeLayerRootWayland;
+
+/*
+ * WaylandVsyncSource
+ *
+ * This class provides a per-widget VsyncSource under Wayland, emulated using
+ * frame callbacks on the widget surface with empty surface commits.
+ *
+ * Wayland does not expose vsync/vblank, as it considers that an implementation
+ * detail the clients should not concern themselves with. Instead, frame
+ * callbacks are provided whenever the compositor believes it is a good time to
+ * start drawing the next frame for a particular surface, giving us as much
+ * time as possible to do so.
+ *
+ * Note that the compositor sends frame callbacks only when it sees fit, and
+ * when that may be is entirely up to the compositor. One cannot expect a
+ * certain rate of callbacks, or any callbacks at all. Examples of common
+ * variations would be surfaces moved between outputs with different refresh
+ * rates, and surfaces that are hidden and therefore do not receieve any
+ * callbacks at all. Other hypothetical scenarios of variation could be
+ * throttling to conserve power, or because a user has requested it.
+ *
+ */
+class WaylandVsyncSource final : public gfx::VsyncSource {
+ public:
+  explicit WaylandVsyncSource(nsWindow* aWindow);
+  virtual ~WaylandVsyncSource();
+
+  static Maybe<TimeDuration> GetFastestVsyncRate();
+
+  void MaybeUpdateSource(MozContainer* aContainer);
+  void MaybeUpdateSource(
+      const RefPtr<NativeLayerRootWayland>& aNativeLayerRoot);
+
+  void EnableMonitor();
+  void DisableMonitor();
+
+  void FrameCallback(wl_callback* aCallback, uint32_t aTime);
+  // Returns whether we should keep firing.
+  bool IdleCallback();
+
+  TimeDuration GetVsyncRate() override;
+
+  void EnableVsync() override;
+
+  void DisableVsync() override;
+
+  bool IsVsyncEnabled() override;
+
+  void Shutdown() override;
+
+ private:
+  Maybe<TimeDuration> GetVsyncRateIfEnabled();
+
+  void Refresh(const MutexAutoLock& aProofOfLock);
+  void SetupFrameCallback(const MutexAutoLock& aProofOfLock);
+  void CalculateVsyncRate(const MutexAutoLock& aProofOfLock,
+                          TimeStamp aVsyncTimestamp);
+  void* GetWindowForLogging() { return mWindow; };
+
+  Mutex mMutex;
+  bool mIsShutdown MOZ_GUARDED_BY(mMutex) = false;
+  bool mVsyncEnabled MOZ_GUARDED_BY(mMutex) = false;
+  bool mMonitorEnabled MOZ_GUARDED_BY(mMutex) = false;
+  bool mCallbackRequested MOZ_GUARDED_BY(mMutex) = false;
+  MozContainer* mContainer MOZ_GUARDED_BY(mMutex) = nullptr;
+  RefPtr<NativeLayerRootWayland> mNativeLayerRoot MOZ_GUARDED_BY(mMutex);
+  TimeDuration mVsyncRate MOZ_GUARDED_BY(mMutex);
+  TimeStamp mLastVsyncTimeStamp MOZ_GUARDED_BY(mMutex);
+  wl_callback* mCallback MOZ_GUARDED_BY(mMutex) = nullptr;
+
+  guint mIdleTimerID = 0;   // Main thread only.
+  nsWindow* const mWindow;  // Main thread only, except for logging.
+  const guint mIdleTimeout;
+};
+
+}  // namespace mozilla
+
+#endif  // _WaylandVsyncSource_h_
diff --git a/widget/gtk/WidgetStyleCache.cpp b/widget/gtk/WidgetStyleCache.cpp
new file mode 100644
index 0000000000..b7c1cf8a9f
--- /dev/null
+++ b/widget/gtk/WidgetStyleCache.cpp
@@ -0,0 +1,1434 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <dlfcn.h>
+#include <gtk/gtk.h>
+#include "WidgetStyleCache.h"
+#include "gtkdrawing.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/PodOperations.h"
+#include "mozilla/ScopeExit.h"
+#include "nsDebug.h"
+#include "nsPrintfCString.h"
+#include "nsString.h"
+
+#define STATE_FLAG_DIR_LTR (1U << 7)
+#define STATE_FLAG_DIR_RTL (1U << 8)
+static_assert(GTK_STATE_FLAG_DIR_LTR == STATE_FLAG_DIR_LTR &&
+                  GTK_STATE_FLAG_DIR_RTL == STATE_FLAG_DIR_RTL,
+              "incorrect direction state flags");
+
+enum class CSDStyle {
+  Unknown,
+  Solid,
+  Normal,
+};
+
+static bool gHeaderBarShouldDrawContainer = false;
+static bool gMaximizedHeaderBarShouldDrawContainer = false;
+static CSDStyle gCSDStyle = CSDStyle::Unknown;
+static GtkWidget* sWidgetStorage[MOZ_GTK_WIDGET_NODE_COUNT];
+static GtkStyleContext* sStyleStorage[MOZ_GTK_WIDGET_NODE_COUNT];
+
+static GtkStyleContext* GetWidgetRootStyle(WidgetNodeType aNodeType);
+static GtkStyleContext* GetCssNodeStyleInternal(WidgetNodeType aNodeType);
+
+static GtkWidget* CreateWindowWidget() {
+  GtkWidget* widget = gtk_window_new(GTK_WINDOW_POPUP);
+  MOZ_RELEASE_ASSERT(widget, "We're missing GtkWindow widget!");
+  gtk_widget_set_name(widget, "MozillaGtkWidget");
+  return widget;
+}
+
+static GtkWidget* CreateWindowContainerWidget() {
+  GtkWidget* widget = gtk_fixed_new();
+  gtk_container_add(GTK_CONTAINER(GetWidget(MOZ_GTK_WINDOW)), widget);
+  return widget;
+}
+
+static void AddToWindowContainer(GtkWidget* widget) {
+  gtk_container_add(GTK_CONTAINER(GetWidget(MOZ_GTK_WINDOW_CONTAINER)), widget);
+}
+
+static GtkWidget* CreateScrollbarWidget(WidgetNodeType aAppearance,
+                                        GtkOrientation aOrientation) {
+  GtkWidget* widget = gtk_scrollbar_new(aOrientation, nullptr);
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateCheckboxWidget() {
+  GtkWidget* widget = gtk_check_button_new_with_label("M");
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateRadiobuttonWidget() {
+  GtkWidget* widget = gtk_radio_button_new_with_label(nullptr, "M");
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateMenuPopupWidget() {
+  GtkWidget* widget = gtk_menu_new();
+  GtkStyleContext* style = gtk_widget_get_style_context(widget);
+  gtk_style_context_add_class(style, GTK_STYLE_CLASS_POPUP);
+  gtk_menu_attach_to_widget(GTK_MENU(widget), GetWidget(MOZ_GTK_WINDOW),
+                            nullptr);
+  return widget;
+}
+
+static GtkWidget* CreateMenuBarWidget() {
+  GtkWidget* widget = gtk_menu_bar_new();
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateProgressWidget() {
+  GtkWidget* widget = gtk_progress_bar_new();
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateTooltipWidget() {
+  MOZ_ASSERT(gtk_check_version(3, 20, 0) != nullptr,
+             "CreateTooltipWidget should be used for Gtk < 3.20 only.");
+  GtkWidget* widget = CreateWindowWidget();
+  GtkStyleContext* style = gtk_widget_get_style_context(widget);
+  gtk_style_context_add_class(style, GTK_STYLE_CLASS_TOOLTIP);
+  return widget;
+}
+
+static GtkWidget* CreateExpanderWidget() {
+  GtkWidget* widget = gtk_expander_new("M");
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateFrameWidget() {
+  GtkWidget* widget = gtk_frame_new(nullptr);
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateButtonWidget() {
+  GtkWidget* widget = gtk_button_new_with_label("M");
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateToggleButtonWidget() {
+  GtkWidget* widget = gtk_toggle_button_new();
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateButtonArrowWidget() {
+  GtkWidget* widget = gtk_arrow_new(GTK_ARROW_DOWN, GTK_SHADOW_OUT);
+  gtk_container_add(GTK_CONTAINER(GetWidget(MOZ_GTK_TOGGLE_BUTTON)), widget);
+  gtk_widget_show(widget);
+  return widget;
+}
+
+static GtkWidget* CreateSpinWidget() {
+  GtkWidget* widget = gtk_spin_button_new(nullptr, 1, 0);
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateEntryWidget() {
+  GtkWidget* widget = gtk_entry_new();
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateComboBoxWidget() {
+  GtkWidget* widget = gtk_combo_box_new();
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+typedef struct {
+  GType type;
+  GtkWidget** widget;
+} GtkInnerWidgetInfo;
+
+static void GetInnerWidget(GtkWidget* widget, gpointer client_data) {
+  auto info = static_cast<GtkInnerWidgetInfo*>(client_data);
+
+  if (G_TYPE_CHECK_INSTANCE_TYPE(widget, info->type)) {
+    *info->widget = widget;
+  }
+}
+
+static GtkWidget* CreateComboBoxButtonWidget() {
+  GtkWidget* comboBox = GetWidget(MOZ_GTK_COMBOBOX);
+  GtkWidget* comboBoxButton = nullptr;
+
+  /* Get its inner Button */
+  GtkInnerWidgetInfo info = {GTK_TYPE_TOGGLE_BUTTON, &comboBoxButton};
+  gtk_container_forall(GTK_CONTAINER(comboBox), GetInnerWidget, &info);
+
+  if (!comboBoxButton) {
+    /* Shouldn't be reached with current internal gtk implementation; we
+     * use a generic toggle button as last resort fallback to avoid
+     * crashing. */
+    comboBoxButton = GetWidget(MOZ_GTK_TOGGLE_BUTTON);
+  } else {
+    /* We need to have pointers to the inner widgets (button, separator, arrow)
+     * of the ComboBox to get the correct rendering from theme engines which
+     * special cases their look. Since the inner layout can change, we ask GTK
+     * to NULL our pointers when they are about to become invalid because the
+     * corresponding widgets don't exist anymore. It's the role of
+     * g_object_add_weak_pointer().
+     * Note that if we don't find the inner widgets (which shouldn't happen), we
+     * fallback to use generic "non-inner" widgets, and they don't need that
+     * kind of weak pointer since they are explicit children of gProtoLayout and
+     * as such GTK holds a strong reference to them. */
+    g_object_add_weak_pointer(
+        G_OBJECT(comboBoxButton),
+        reinterpret_cast<gpointer*>(sWidgetStorage) + MOZ_GTK_COMBOBOX_BUTTON);
+  }
+
+  return comboBoxButton;
+}
+
+static GtkWidget* CreateComboBoxArrowWidget() {
+  GtkWidget* comboBoxButton = GetWidget(MOZ_GTK_COMBOBOX_BUTTON);
+  GtkWidget* comboBoxArrow = nullptr;
+
+  /* Get the widgets inside the Button */
+  GtkWidget* buttonChild = gtk_bin_get_child(GTK_BIN(comboBoxButton));
+  if (GTK_IS_BOX(buttonChild)) {
+    /* appears-as-list = FALSE, cell-view = TRUE; the button
+     * contains an hbox. This hbox is there because the ComboBox
+     * needs to place a cell renderer, a separator, and an arrow in
+     * the button when appears-as-list is FALSE. */
+    GtkInnerWidgetInfo info = {GTK_TYPE_ARROW, &comboBoxArrow};
+    gtk_container_forall(GTK_CONTAINER(buttonChild), GetInnerWidget, &info);
+  } else if (GTK_IS_ARROW(buttonChild)) {
+    /* appears-as-list = TRUE, or cell-view = FALSE;
+     * the button only contains an arrow */
+    comboBoxArrow = buttonChild;
+  }
+
+  if (!comboBoxArrow) {
+    /* Shouldn't be reached with current internal gtk implementation;
+     * we gButtonArrowWidget as last resort fallback to avoid
+     * crashing. */
+    comboBoxArrow = GetWidget(MOZ_GTK_BUTTON_ARROW);
+  } else {
+    g_object_add_weak_pointer(
+        G_OBJECT(comboBoxArrow),
+        reinterpret_cast<gpointer*>(sWidgetStorage) + MOZ_GTK_COMBOBOX_ARROW);
+  }
+
+  return comboBoxArrow;
+}
+
+static GtkWidget* CreateComboBoxSeparatorWidget() {
+  // Ensure to search for separator only once as it can fail
+  // TODO - it won't initialize after ResetWidgetCache() call
+  static bool isMissingSeparator = false;
+  if (isMissingSeparator) return nullptr;
+
+  /* Get the widgets inside the Button */
+  GtkWidget* comboBoxSeparator = nullptr;
+  GtkWidget* buttonChild =
+      gtk_bin_get_child(GTK_BIN(GetWidget(MOZ_GTK_COMBOBOX_BUTTON)));
+  if (GTK_IS_BOX(buttonChild)) {
+    /* appears-as-list = FALSE, cell-view = TRUE; the button
+     * contains an hbox. This hbox is there because the ComboBox
+     * needs to place a cell renderer, a separator, and an arrow in
+     * the button when appears-as-list is FALSE. */
+    GtkInnerWidgetInfo info = {GTK_TYPE_SEPARATOR, &comboBoxSeparator};
+    gtk_container_forall(GTK_CONTAINER(buttonChild), GetInnerWidget, &info);
+  }
+
+  if (comboBoxSeparator) {
+    g_object_add_weak_pointer(G_OBJECT(comboBoxSeparator),
+                              reinterpret_cast<gpointer*>(sWidgetStorage) +
+                                  MOZ_GTK_COMBOBOX_SEPARATOR);
+  } else {
+    /* comboBoxSeparator may be NULL
+     * when "appears-as-list" = TRUE or "cell-view" = FALSE;
+     * if there is no separator, then we just won't paint it. */
+    isMissingSeparator = true;
+  }
+
+  return comboBoxSeparator;
+}
+
+static GtkWidget* CreateComboBoxEntryWidget() {
+  GtkWidget* widget = gtk_combo_box_new_with_entry();
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateComboBoxEntryTextareaWidget() {
+  GtkWidget* comboBoxTextarea = nullptr;
+
+  /* Get its inner Entry and Button */
+  GtkInnerWidgetInfo info = {GTK_TYPE_ENTRY, &comboBoxTextarea};
+  gtk_container_forall(GTK_CONTAINER(GetWidget(MOZ_GTK_COMBOBOX_ENTRY)),
+                       GetInnerWidget, &info);
+
+  if (!comboBoxTextarea) {
+    comboBoxTextarea = GetWidget(MOZ_GTK_ENTRY);
+  } else {
+    g_object_add_weak_pointer(
+        G_OBJECT(comboBoxTextarea),
+        reinterpret_cast<gpointer*>(sWidgetStorage) + MOZ_GTK_COMBOBOX_ENTRY);
+  }
+
+  return comboBoxTextarea;
+}
+
+static GtkWidget* CreateComboBoxEntryButtonWidget() {
+  GtkWidget* comboBoxButton = nullptr;
+
+  /* Get its inner Entry and Button */
+  GtkInnerWidgetInfo info = {GTK_TYPE_TOGGLE_BUTTON, &comboBoxButton};
+  gtk_container_forall(GTK_CONTAINER(GetWidget(MOZ_GTK_COMBOBOX_ENTRY)),
+                       GetInnerWidget, &info);
+
+  if (!comboBoxButton) {
+    comboBoxButton = GetWidget(MOZ_GTK_TOGGLE_BUTTON);
+  } else {
+    g_object_add_weak_pointer(G_OBJECT(comboBoxButton),
+                              reinterpret_cast<gpointer*>(sWidgetStorage) +
+                                  MOZ_GTK_COMBOBOX_ENTRY_BUTTON);
+  }
+
+  return comboBoxButton;
+}
+
+static GtkWidget* CreateComboBoxEntryArrowWidget() {
+  GtkWidget* comboBoxArrow = nullptr;
+
+  /* Get the Arrow inside the Button */
+  GtkWidget* buttonChild =
+      gtk_bin_get_child(GTK_BIN(GetWidget(MOZ_GTK_COMBOBOX_ENTRY_BUTTON)));
+
+  if (GTK_IS_BOX(buttonChild)) {
+    /* appears-as-list = FALSE, cell-view = TRUE; the button
+     * contains an hbox. This hbox is there because the ComboBox
+     * needs to place a cell renderer, a separator, and an arrow in
+     * the button when appears-as-list is FALSE. */
+    GtkInnerWidgetInfo info = {GTK_TYPE_ARROW, &comboBoxArrow};
+    gtk_container_forall(GTK_CONTAINER(buttonChild), GetInnerWidget, &info);
+  } else if (GTK_IS_ARROW(buttonChild)) {
+    /* appears-as-list = TRUE, or cell-view = FALSE;
+     * the button only contains an arrow */
+    comboBoxArrow = buttonChild;
+  }
+
+  if (!comboBoxArrow) {
+    /* Shouldn't be reached with current internal gtk implementation;
+     * we gButtonArrowWidget as last resort fallback to avoid
+     * crashing. */
+    comboBoxArrow = GetWidget(MOZ_GTK_BUTTON_ARROW);
+  } else {
+    g_object_add_weak_pointer(G_OBJECT(comboBoxArrow),
+                              reinterpret_cast<gpointer*>(sWidgetStorage) +
+                                  MOZ_GTK_COMBOBOX_ENTRY_ARROW);
+  }
+
+  return comboBoxArrow;
+}
+
+static GtkWidget* CreateScrolledWindowWidget() {
+  GtkWidget* widget = gtk_scrolled_window_new(nullptr, nullptr);
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateTreeViewWidget() {
+  GtkWidget* widget = gtk_tree_view_new();
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateTreeHeaderCellWidget() {
+  /*
+   * Some GTK engines paint the first and last cell
+   * of a TreeView header with a highlight.
+   * Since we do not know where our widget will be relative
+   * to the other buttons in the TreeView header, we must
+   * paint it as a button that is between two others,
+   * thus ensuring it is neither the first or last button
+   * in the header.
+   * GTK doesn't give us a way to do this explicitly,
+   * so we must paint with a button that is between two
+   * others.
+   */
+  GtkTreeViewColumn* firstTreeViewColumn;
+  GtkTreeViewColumn* middleTreeViewColumn;
+  GtkTreeViewColumn* lastTreeViewColumn;
+
+  GtkWidget* treeView = GetWidget(MOZ_GTK_TREEVIEW);
+
+  /* Create and append our three columns */
+  firstTreeViewColumn = gtk_tree_view_column_new();
+  gtk_tree_view_column_set_title(firstTreeViewColumn, "M");
+  gtk_tree_view_append_column(GTK_TREE_VIEW(treeView), firstTreeViewColumn);
+
+  middleTreeViewColumn = gtk_tree_view_column_new();
+  gtk_tree_view_column_set_title(middleTreeViewColumn, "M");
+  gtk_tree_view_append_column(GTK_TREE_VIEW(treeView), middleTreeViewColumn);
+
+  lastTreeViewColumn = gtk_tree_view_column_new();
+  gtk_tree_view_column_set_title(lastTreeViewColumn, "M");
+  gtk_tree_view_append_column(GTK_TREE_VIEW(treeView), lastTreeViewColumn);
+
+  /* Use the middle column's header for our button */
+  return gtk_tree_view_column_get_button(middleTreeViewColumn);
+}
+
+static GtkWidget* CreateHPanedWidget() {
+  GtkWidget* widget = gtk_paned_new(GTK_ORIENTATION_HORIZONTAL);
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateVPanedWidget() {
+  GtkWidget* widget = gtk_paned_new(GTK_ORIENTATION_VERTICAL);
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateScaleWidget(GtkOrientation aOrientation) {
+  GtkWidget* widget = gtk_scale_new(aOrientation, nullptr);
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static GtkWidget* CreateNotebookWidget() {
+  GtkWidget* widget = gtk_notebook_new();
+  AddToWindowContainer(widget);
+  return widget;
+}
+
+static bool HasBackground(GtkStyleContext* aStyle) {
+  GdkRGBA gdkColor;
+  gtk_style_context_get_background_color(aStyle, GTK_STATE_FLAG_NORMAL,
+                                         &gdkColor);
+  if (gdkColor.alpha != 0.0) {
+    return true;
+  }
+
+  GValue value = G_VALUE_INIT;
+  gtk_style_context_get_property(aStyle, "background-image",
+                                 GTK_STATE_FLAG_NORMAL, &value);
+  auto cleanup = mozilla::MakeScopeExit([&] { g_value_unset(&value); });
+  return g_value_get_boxed(&value);
+}
+
+static void CreateHeaderBarWidget(WidgetNodeType aAppearance) {
+  GtkWidget* window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+  GtkStyleContext* windowStyle = gtk_widget_get_style_context(window);
+
+  // Headerbar has to be placed to window with csd or solid-csd style
+  // to properly draw the decorated.
+  gtk_style_context_add_class(windowStyle,
+                              IsSolidCSDStyleUsed() ? "solid-csd" : "csd");
+
+  GtkWidget* fixed = gtk_fixed_new();
+  GtkStyleContext* fixedStyle = gtk_widget_get_style_context(fixed);
+  gtk_style_context_add_class(fixedStyle, "titlebar");
+
+  GtkWidget* headerBar = gtk_header_bar_new();
+
+  // Emulate what create_titlebar() at gtkwindow.c does.
+  GtkStyleContext* headerBarStyle = gtk_widget_get_style_context(headerBar);
+  gtk_style_context_add_class(headerBarStyle, "titlebar");
+
+  // TODO: Define default-decoration titlebar style as workaround
+  // to ensure the titlebar buttons does not overflow outside.
+  // Recently the titlebar size is calculated as
+  // tab size + titlebar border/padding (default-decoration has 6px padding
+  // at default Adwaita theme).
+  // We need to fix titlebar size calculation to also include
+  // titlebar button sizes. (Bug 1419442)
+  gtk_style_context_add_class(headerBarStyle, "default-decoration");
+
+  sWidgetStorage[aAppearance] = headerBar;
+  if (aAppearance == MOZ_GTK_HEADER_BAR_MAXIMIZED) {
+    MOZ_ASSERT(!sWidgetStorage[MOZ_GTK_HEADERBAR_WINDOW_MAXIMIZED],
+               "Window widget is already created!");
+    MOZ_ASSERT(!sWidgetStorage[MOZ_GTK_HEADERBAR_FIXED_MAXIMIZED],
+               "Fixed widget is already created!");
+
+    gtk_style_context_add_class(windowStyle, "maximized");
+
+    sWidgetStorage[MOZ_GTK_HEADERBAR_WINDOW_MAXIMIZED] = window;
+    sWidgetStorage[MOZ_GTK_HEADERBAR_FIXED_MAXIMIZED] = fixed;
+  } else {
+    MOZ_ASSERT(!sWidgetStorage[MOZ_GTK_HEADERBAR_WINDOW],
+               "Window widget is already created!");
+    MOZ_ASSERT(!sWidgetStorage[MOZ_GTK_HEADERBAR_FIXED],
+               "Fixed widget is already created!");
+    sWidgetStorage[MOZ_GTK_HEADERBAR_WINDOW] = window;
+    sWidgetStorage[MOZ_GTK_HEADERBAR_FIXED] = fixed;
+  }
+
+  gtk_container_add(GTK_CONTAINER(window), fixed);
+  gtk_container_add(GTK_CONTAINER(fixed), headerBar);
+
+  gtk_style_context_invalidate(headerBarStyle);
+  gtk_style_context_invalidate(fixedStyle);
+
+  // Some themes like Elementary's style the container of the headerbar rather
+  // than the header bar itself.
+  bool& shouldDrawContainer = aAppearance == MOZ_GTK_HEADER_BAR
+                                  ? gHeaderBarShouldDrawContainer
+                                  : gMaximizedHeaderBarShouldDrawContainer;
+  shouldDrawContainer = [&] {
+    const bool headerBarHasBackground = HasBackground(headerBarStyle);
+    if (headerBarHasBackground && GetBorderRadius(headerBarStyle)) {
+      return false;
+    }
+    if (HasBackground(fixedStyle) &&
+        (GetBorderRadius(fixedStyle) || !headerBarHasBackground)) {
+      return true;
+    }
+    return false;
+  }();
+}
+
+#define ICON_SCALE_VARIANTS 2
+
+static void LoadWidgetIconPixbuf(GtkWidget* aWidgetIcon) {
+  GtkStyleContext* style = gtk_widget_get_style_context(aWidgetIcon);
+
+  const gchar* iconName;
+  GtkIconSize gtkIconSize;
+  gtk_image_get_icon_name(GTK_IMAGE(aWidgetIcon), &iconName, &gtkIconSize);
+
+  gint iconWidth, iconHeight;
+  gtk_icon_size_lookup(gtkIconSize, &iconWidth, &iconHeight);
+
+  /* Those are available since Gtk+ 3.10 as well as GtkHeaderBar */
+  for (int scale = 1; scale < ICON_SCALE_VARIANTS + 1; scale++) {
+    GtkIconInfo* gtkIconInfo = gtk_icon_theme_lookup_icon_for_scale(
+        gtk_icon_theme_get_default(), iconName, iconWidth, scale,
+        (GtkIconLookupFlags)0);
+
+    if (!gtkIconInfo) {
+      // We miss the icon, nothing to do here.
+      return;
+    }
+
+    gboolean unused;
+    GdkPixbuf* iconPixbuf = gtk_icon_info_load_symbolic_for_context(
+        gtkIconInfo, style, &unused, nullptr);
+    g_object_unref(G_OBJECT(gtkIconInfo));
+
+    cairo_surface_t* iconSurface =
+        gdk_cairo_surface_create_from_pixbuf(iconPixbuf, scale, nullptr);
+    g_object_unref(iconPixbuf);
+
+    nsPrintfCString surfaceName("MozillaIconSurface%d", scale);
+    g_object_set_data_full(G_OBJECT(aWidgetIcon), surfaceName.get(),
+                           iconSurface, (GDestroyNotify)cairo_surface_destroy);
+  }
+}
+
+cairo_surface_t* GetWidgetIconSurface(GtkWidget* aWidgetIcon, int aScale) {
+  if (aScale > ICON_SCALE_VARIANTS) {
+    aScale = ICON_SCALE_VARIANTS;
+  }
+
+  nsPrintfCString surfaceName("MozillaIconSurface%d", aScale);
+  return (cairo_surface_t*)g_object_get_data(G_OBJECT(aWidgetIcon),
+                                             surfaceName.get());
+}
+
+static void CreateHeaderBarButton(GtkWidget* aParentWidget,
+                                  WidgetNodeType aAppearance) {
+  GtkWidget* widget = gtk_button_new();
+
+  // We have to add button to widget hierarchy now to pick
+  // right icon style at LoadWidgetIconPixbuf().
+  if (GTK_IS_BOX(aParentWidget)) {
+    gtk_box_pack_start(GTK_BOX(aParentWidget), widget, FALSE, FALSE, 0);
+  } else {
+    gtk_container_add(GTK_CONTAINER(aParentWidget), widget);
+  }
+
+  // We bypass GetWidget() here because we create all titlebar
+  // buttons at once when a first one is requested.
+  NS_ASSERTION(!sWidgetStorage[aAppearance],
+               "Titlebar button is already created!");
+  sWidgetStorage[aAppearance] = widget;
+
+  // We need to show the button widget now as GtkBox does not
+  // place invisible widgets and we'll miss first-child/last-child
+  // css selectors at the buttons otherwise.
+  gtk_widget_show(widget);
+
+  GtkStyleContext* style = gtk_widget_get_style_context(widget);
+  gtk_style_context_add_class(style, "titlebutton");
+
+  GtkWidget* image = nullptr;
+  switch (aAppearance) {
+    case MOZ_GTK_HEADER_BAR_BUTTON_CLOSE:
+      gtk_style_context_add_class(style, "close");
+      image = gtk_image_new_from_icon_name("window-close-symbolic",
+                                           GTK_ICON_SIZE_MENU);
+      break;
+    case MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE:
+      gtk_style_context_add_class(style, "minimize");
+      image = gtk_image_new_from_icon_name("window-minimize-symbolic",
+                                           GTK_ICON_SIZE_MENU);
+      break;
+
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE:
+      gtk_style_context_add_class(style, "maximize");
+      image = gtk_image_new_from_icon_name("window-maximize-symbolic",
+                                           GTK_ICON_SIZE_MENU);
+      break;
+
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE:
+      gtk_style_context_add_class(style, "maximize");
+      image = gtk_image_new_from_icon_name("window-restore-symbolic",
+                                           GTK_ICON_SIZE_MENU);
+      break;
+    default:
+      break;
+  }
+
+  gtk_widget_set_valign(widget, GTK_ALIGN_CENTER);
+  g_object_set(image, "use-fallback", TRUE, NULL);
+  gtk_container_add(GTK_CONTAINER(widget), image);
+
+  // We bypass GetWidget() here by explicit sWidgetStorage[] update so
+  // invalidate the style as well as GetWidget() does.
+  style = gtk_widget_get_style_context(image);
+  gtk_style_context_invalidate(style);
+
+  LoadWidgetIconPixbuf(image);
+}
+
+static bool IsToolbarButtonEnabled(ButtonLayout* aButtonLayout,
+                                   size_t aButtonNums,
+                                   WidgetNodeType aAppearance) {
+  for (size_t i = 0; i < aButtonNums; i++) {
+    if (aButtonLayout[i].mType == aAppearance) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool IsSolidCSDStyleUsed() {
+  if (gCSDStyle == CSDStyle::Unknown) {
+    bool solid;
+    {
+      GtkWidget* window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+      gtk_window_set_titlebar(GTK_WINDOW(window), gtk_header_bar_new());
+      gtk_widget_realize(window);
+      GtkStyleContext* windowStyle = gtk_widget_get_style_context(window);
+      solid = gtk_style_context_has_class(windowStyle, "solid-csd");
+      gtk_widget_destroy(window);
+    }
+    gCSDStyle = solid ? CSDStyle::Solid : CSDStyle::Normal;
+  }
+  return gCSDStyle == CSDStyle::Solid;
+}
+
+static void CreateHeaderBarButtons() {
+  GtkWidget* headerBar = sWidgetStorage[MOZ_GTK_HEADER_BAR];
+  MOZ_ASSERT(headerBar, "We're missing header bar widget!");
+
+  gint buttonSpacing = 6;
+  g_object_get(headerBar, "spacing", &buttonSpacing, nullptr);
+
+  GtkWidget* buttonBox = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, buttonSpacing);
+  gtk_container_add(GTK_CONTAINER(headerBar), buttonBox);
+  // We support only LTR headerbar layout for now.
+  gtk_style_context_add_class(gtk_widget_get_style_context(buttonBox),
+                              GTK_STYLE_CLASS_LEFT);
+
+  ButtonLayout buttonLayout[TOOLBAR_BUTTONS];
+
+  size_t activeButtons =
+      GetGtkHeaderBarButtonLayout(mozilla::Span(buttonLayout), nullptr);
+
+  if (IsToolbarButtonEnabled(buttonLayout, activeButtons,
+                             MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE)) {
+    CreateHeaderBarButton(buttonBox, MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE);
+  }
+  if (IsToolbarButtonEnabled(buttonLayout, activeButtons,
+                             MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE)) {
+    CreateHeaderBarButton(buttonBox, MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE);
+    // We don't pack "restore" headerbar button to box as it's an icon
+    // placeholder. Pack it only to header bar to get correct style.
+    CreateHeaderBarButton(GetWidget(MOZ_GTK_HEADER_BAR_MAXIMIZED),
+                          MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE);
+  }
+  if (IsToolbarButtonEnabled(buttonLayout, activeButtons,
+                             MOZ_GTK_HEADER_BAR_BUTTON_CLOSE)) {
+    CreateHeaderBarButton(buttonBox, MOZ_GTK_HEADER_BAR_BUTTON_CLOSE);
+  }
+}
+
+static void CreateHeaderBar() {
+  CreateHeaderBarWidget(MOZ_GTK_HEADER_BAR);
+  CreateHeaderBarWidget(MOZ_GTK_HEADER_BAR_MAXIMIZED);
+  CreateHeaderBarButtons();
+}
+
+static GtkWidget* CreateWidget(WidgetNodeType aAppearance) {
+  switch (aAppearance) {
+    case MOZ_GTK_WINDOW:
+      return CreateWindowWidget();
+    case MOZ_GTK_WINDOW_CONTAINER:
+      return CreateWindowContainerWidget();
+    case MOZ_GTK_CHECKBUTTON_CONTAINER:
+      return CreateCheckboxWidget();
+    case MOZ_GTK_PROGRESSBAR:
+      return CreateProgressWidget();
+    case MOZ_GTK_RADIOBUTTON_CONTAINER:
+      return CreateRadiobuttonWidget();
+    case MOZ_GTK_SCROLLBAR_VERTICAL:
+      return CreateScrollbarWidget(aAppearance, GTK_ORIENTATION_VERTICAL);
+    case MOZ_GTK_MENUPOPUP:
+      return CreateMenuPopupWidget();
+    case MOZ_GTK_MENUBAR:
+      return CreateMenuBarWidget();
+    case MOZ_GTK_EXPANDER:
+      return CreateExpanderWidget();
+    case MOZ_GTK_FRAME:
+      return CreateFrameWidget();
+    case MOZ_GTK_SPINBUTTON:
+      return CreateSpinWidget();
+    case MOZ_GTK_BUTTON:
+      return CreateButtonWidget();
+    case MOZ_GTK_TOGGLE_BUTTON:
+      return CreateToggleButtonWidget();
+    case MOZ_GTK_BUTTON_ARROW:
+      return CreateButtonArrowWidget();
+    case MOZ_GTK_ENTRY:
+    case MOZ_GTK_DROPDOWN_ENTRY:
+      return CreateEntryWidget();
+    case MOZ_GTK_SCROLLED_WINDOW:
+      return CreateScrolledWindowWidget();
+    case MOZ_GTK_TREEVIEW:
+      return CreateTreeViewWidget();
+    case MOZ_GTK_TREE_HEADER_CELL:
+      return CreateTreeHeaderCellWidget();
+    case MOZ_GTK_SPLITTER_HORIZONTAL:
+      return CreateHPanedWidget();
+    case MOZ_GTK_SPLITTER_VERTICAL:
+      return CreateVPanedWidget();
+    case MOZ_GTK_SCALE_HORIZONTAL:
+      return CreateScaleWidget(GTK_ORIENTATION_HORIZONTAL);
+    case MOZ_GTK_SCALE_VERTICAL:
+      return CreateScaleWidget(GTK_ORIENTATION_VERTICAL);
+    case MOZ_GTK_NOTEBOOK:
+      return CreateNotebookWidget();
+    case MOZ_GTK_COMBOBOX:
+      return CreateComboBoxWidget();
+    case MOZ_GTK_COMBOBOX_BUTTON:
+      return CreateComboBoxButtonWidget();
+    case MOZ_GTK_COMBOBOX_ARROW:
+      return CreateComboBoxArrowWidget();
+    case MOZ_GTK_COMBOBOX_SEPARATOR:
+      return CreateComboBoxSeparatorWidget();
+    case MOZ_GTK_COMBOBOX_ENTRY:
+      return CreateComboBoxEntryWidget();
+    case MOZ_GTK_COMBOBOX_ENTRY_TEXTAREA:
+      return CreateComboBoxEntryTextareaWidget();
+    case MOZ_GTK_COMBOBOX_ENTRY_BUTTON:
+      return CreateComboBoxEntryButtonWidget();
+    case MOZ_GTK_COMBOBOX_ENTRY_ARROW:
+      return CreateComboBoxEntryArrowWidget();
+    case MOZ_GTK_HEADERBAR_WINDOW:
+    case MOZ_GTK_HEADERBAR_WINDOW_MAXIMIZED:
+    case MOZ_GTK_HEADERBAR_FIXED:
+    case MOZ_GTK_HEADERBAR_FIXED_MAXIMIZED:
+    case MOZ_GTK_HEADER_BAR:
+    case MOZ_GTK_HEADER_BAR_MAXIMIZED:
+    case MOZ_GTK_HEADER_BAR_BUTTON_CLOSE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE:
+      /* Create header bar widgets once and fill with child elements as we need
+         the header bar fully configured to get a correct style */
+      CreateHeaderBar();
+      return sWidgetStorage[aAppearance];
+    default:
+      /* Not implemented */
+      return nullptr;
+  }
+}
+
+GtkWidget* GetWidget(WidgetNodeType aAppearance) {
+  GtkWidget* widget = sWidgetStorage[aAppearance];
+  if (!widget) {
+    widget = CreateWidget(aAppearance);
+    // Some widgets (MOZ_GTK_COMBOBOX_SEPARATOR for instance) may not be
+    // available or implemented.
+    if (!widget) {
+      return nullptr;
+    }
+    // In GTK versions prior to 3.18, automatic invalidation of style contexts
+    // for widgets was delayed until the next resize event.  Gecko however,
+    // typically uses the style context before the resize event runs and so an
+    // explicit invalidation may be required.  This is necessary if a style
+    // property was retrieved before all changes were made to the style
+    // context.  One such situation is where gtk_button_construct_child()
+    // retrieves the style property "image-spacing" during construction of the
+    // GtkButton, before its parent is set to provide inheritance of ancestor
+    // properties.  More recent GTK versions do not need this, but do not
+    // re-resolve until required and so invalidation does not trigger
+    // unnecessary resolution in general.
+    GtkStyleContext* style = gtk_widget_get_style_context(widget);
+    gtk_style_context_invalidate(style);
+
+    sWidgetStorage[aAppearance] = widget;
+  }
+  return widget;
+}
+
+static void AddStyleClassesFromStyle(GtkStyleContext* aDest,
+                                     GtkStyleContext* aSrc) {
+  GList* classes = gtk_style_context_list_classes(aSrc);
+  for (GList* link = classes; link; link = link->next) {
+    gtk_style_context_add_class(aDest, static_cast<gchar*>(link->data));
+  }
+  g_list_free(classes);
+}
+
+GtkStyleContext* CreateStyleForWidget(GtkWidget* aWidget,
+                                      GtkStyleContext* aParentStyle) {
+  static auto sGtkWidgetClassGetCSSName =
+      reinterpret_cast<const char* (*)(GtkWidgetClass*)>(
+          dlsym(RTLD_DEFAULT, "gtk_widget_class_get_css_name"));
+
+  GtkWidgetClass* widgetClass = GTK_WIDGET_GET_CLASS(aWidget);
+  const gchar* name = sGtkWidgetClassGetCSSName
+                          ? sGtkWidgetClassGetCSSName(widgetClass)
+                          : nullptr;
+
+  GtkStyleContext* context =
+      CreateCSSNode(name, aParentStyle, G_TYPE_FROM_CLASS(widgetClass));
+
+  // Classes are stored on the style context instead of the path so that any
+  // future gtk_style_context_save() will inherit classes on the head CSS
+  // node, in the same way as happens when called on a style context owned by
+  // a widget.
+  //
+  // Classes can be stored on a GtkCssNodeDeclaration and/or the path.
+  // gtk_style_context_save() reuses the GtkCssNodeDeclaration, and appends a
+  // new object to the path, without copying the classes from the old path
+  // head.  The new head picks up classes from the GtkCssNodeDeclaration, but
+  // not the path.  GtkWidgets store their classes on the
+  // GtkCssNodeDeclaration, so make sure to add classes there.
+  //
+  // Picking up classes from the style context also means that
+  // https://bugzilla.gnome.org/show_bug.cgi?id=767312, which can stop
+  // gtk_widget_path_append_for_widget() from finding classes in GTK 3.20,
+  // is not a problem.
+  GtkStyleContext* widgetStyle = gtk_widget_get_style_context(aWidget);
+  AddStyleClassesFromStyle(context, widgetStyle);
+
+  // Release any floating reference on aWidget.
+  g_object_ref_sink(aWidget);
+  g_object_unref(aWidget);
+
+  return context;
+}
+
+static GtkStyleContext* CreateStyleForWidget(GtkWidget* aWidget,
+                                             WidgetNodeType aParentType) {
+  return CreateStyleForWidget(aWidget, GetWidgetRootStyle(aParentType));
+}
+
+GtkStyleContext* CreateCSSNode(const char* aName, GtkStyleContext* aParentStyle,
+                               GType aType) {
+  static auto sGtkWidgetPathIterSetObjectName =
+      reinterpret_cast<void (*)(GtkWidgetPath*, gint, const char*)>(
+          dlsym(RTLD_DEFAULT, "gtk_widget_path_iter_set_object_name"));
+
+  GtkWidgetPath* path;
+  if (aParentStyle) {
+    path = gtk_widget_path_copy(gtk_style_context_get_path(aParentStyle));
+    // Copy classes from the parent style context to its corresponding node in
+    // the path, because GTK will only match against ancestor classes if they
+    // are on the path.
+    GList* classes = gtk_style_context_list_classes(aParentStyle);
+    for (GList* link = classes; link; link = link->next) {
+      gtk_widget_path_iter_add_class(path, -1, static_cast<gchar*>(link->data));
+    }
+    g_list_free(classes);
+  } else {
+    path = gtk_widget_path_new();
+  }
+
+  gtk_widget_path_append_type(path, aType);
+
+  if (sGtkWidgetPathIterSetObjectName) {
+    (*sGtkWidgetPathIterSetObjectName)(path, -1, aName);
+  }
+
+  GtkStyleContext* context = gtk_style_context_new();
+  gtk_style_context_set_path(context, path);
+  gtk_style_context_set_parent(context, aParentStyle);
+  gtk_widget_path_unref(path);
+
+  // In GTK 3.4, gtk_render_* functions use |theming_engine| on the style
+  // context without ensuring any style resolution sets it appropriately
+  // in style_data_lookup(). e.g.
+  // https://git.gnome.org/browse/gtk+/tree/gtk/gtkstylecontext.c?h=3.4.4#n3847
+  //
+  // That can result in incorrect drawing on first draw.  To work around this,
+  // force a style look-up to set |theming_engine|.  It is sufficient to do
+  // this only on context creation, instead of after every modification to the
+  // context, because themes typically (Ambiance and oxygen-gtk, at least) set
+  // the "engine" property with the '*' selector.
+  if (GTK_MAJOR_VERSION == 3 && gtk_get_minor_version() < 6) {
+    GdkRGBA unused;
+    gtk_style_context_get_color(context, GTK_STATE_FLAG_NORMAL, &unused);
+  }
+
+  return context;
+}
+
+// Return a style context matching that of the root CSS node of a widget.
+// This is used by all GTK versions.
+static GtkStyleContext* GetWidgetRootStyle(WidgetNodeType aNodeType) {
+  GtkStyleContext* style = sStyleStorage[aNodeType];
+  if (style) return style;
+
+  switch (aNodeType) {
+    case MOZ_GTK_MENUITEM:
+      style = CreateStyleForWidget(gtk_menu_item_new(), MOZ_GTK_MENUPOPUP);
+      break;
+    case MOZ_GTK_MENUBARITEM:
+      style = CreateStyleForWidget(gtk_menu_item_new(), MOZ_GTK_MENUBAR);
+      break;
+    case MOZ_GTK_TEXT_VIEW:
+      style =
+          CreateStyleForWidget(gtk_text_view_new(), MOZ_GTK_SCROLLED_WINDOW);
+      break;
+    case MOZ_GTK_TOOLTIP:
+      if (gtk_check_version(3, 20, 0) != nullptr) {
+        // The tooltip style class is added first in CreateTooltipWidget()
+        // and transfered to style in CreateStyleForWidget().
+        GtkWidget* tooltipWindow = CreateTooltipWidget();
+        style = CreateStyleForWidget(tooltipWindow, nullptr);
+        gtk_widget_destroy(tooltipWindow);  // Release GtkWindow self-reference.
+      } else {
+        // We create this from the path because GtkTooltipWindow is not public.
+        style = CreateCSSNode("tooltip", nullptr, GTK_TYPE_TOOLTIP);
+        gtk_style_context_add_class(style, GTK_STYLE_CLASS_BACKGROUND);
+      }
+      break;
+    case MOZ_GTK_TOOLTIP_BOX:
+      style = CreateStyleForWidget(gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0),
+                                   MOZ_GTK_TOOLTIP);
+      break;
+    case MOZ_GTK_TOOLTIP_BOX_LABEL:
+      style = CreateStyleForWidget(gtk_label_new(nullptr), MOZ_GTK_TOOLTIP_BOX);
+      break;
+    default:
+      GtkWidget* widget = GetWidget(aNodeType);
+      MOZ_ASSERT(widget);
+      return gtk_widget_get_style_context(widget);
+  }
+
+  MOZ_ASSERT(style);
+  sStyleStorage[aNodeType] = style;
+  return style;
+}
+
+static GtkStyleContext* CreateChildCSSNode(const char* aName,
+                                           WidgetNodeType aParentNodeType) {
+  return CreateCSSNode(aName, GetCssNodeStyleInternal(aParentNodeType));
+}
+
+// Create a style context equivalent to a saved root style context of
+// |aAppearance| with |aStyleClass| as an additional class.  This is used to
+// produce a context equivalent to what GTK versions < 3.20 use for many
+// internal parts of widgets.
+static GtkStyleContext* CreateSubStyleWithClass(WidgetNodeType aAppearance,
+                                                const gchar* aStyleClass) {
+  static auto sGtkWidgetPathIterGetObjectName =
+      reinterpret_cast<const char* (*)(const GtkWidgetPath*, gint)>(
+          dlsym(RTLD_DEFAULT, "gtk_widget_path_iter_get_object_name"));
+
+  GtkStyleContext* parentStyle = GetWidgetRootStyle(aAppearance);
+
+  // Create a new context that behaves like |parentStyle| would after
+  // gtk_style_context_save(parentStyle).
+  //
+  // Avoiding gtk_style_context_save() avoids the need to manage the
+  // restore, and a new context permits caching style resolution.
+  //
+  // gtk_style_context_save(context) changes the node hierarchy of |context|
+  // to add a new GtkCssNodeDeclaration that is a copy of its original node.
+  // The new node is a child of the original node, and so the new heirarchy is
+  // one level deeper.  The new node receives the same classes as the
+  // original, but any changes to the classes on |context| will change only
+  // the new node.  The new node inherits properties from the original node
+  // (which retains the original heirarchy and classes) and matches CSS rules
+  // with the new heirarchy and any changes to the classes.
+  //
+  // The change in hierarchy can produce some surprises in matching theme CSS
+  // rules (e.g. https://bugzilla.gnome.org/show_bug.cgi?id=761870#c2), but it
+  // is important here to produce the same behavior so that rules match the
+  // same widget parts in Gecko as they do in GTK.
+  //
+  // When using public GTK API to construct style contexts, a widget path is
+  // required.  CSS rules are not matched against the style context heirarchy
+  // but according to the heirarchy in the widget path.  The path that matches
+  // the same CSS rules as a saved context is like the path of |parentStyle|
+  // but with an extra copy of the head (last) object appended.  Setting
+  // |parentStyle| as the parent context provides the same inheritance of
+  // properties from the widget root node.
+  const GtkWidgetPath* parentPath = gtk_style_context_get_path(parentStyle);
+  const gchar* name = sGtkWidgetPathIterGetObjectName
+                          ? sGtkWidgetPathIterGetObjectName(parentPath, -1)
+                          : nullptr;
+  GType objectType = gtk_widget_path_get_object_type(parentPath);
+
+  GtkStyleContext* style = CreateCSSNode(name, parentStyle, objectType);
+
+  // Start with the same classes on the new node as were on |parentStyle|.
+  // GTK puts no regions or junction_sides on widget root nodes, and so there
+  // is no need to copy these.
+  AddStyleClassesFromStyle(style, parentStyle);
+
+  gtk_style_context_add_class(style, aStyleClass);
+  return style;
+}
+
+/* GetCssNodeStyleInternal is used by Gtk >= 3.20 */
+static GtkStyleContext* GetCssNodeStyleInternal(WidgetNodeType aNodeType) {
+  GtkStyleContext* style = sStyleStorage[aNodeType];
+  if (style) return style;
+
+  switch (aNodeType) {
+    case MOZ_GTK_SCROLLBAR_CONTENTS_VERTICAL:
+      style = CreateChildCSSNode("contents", MOZ_GTK_SCROLLBAR_VERTICAL);
+      break;
+    case MOZ_GTK_SCROLLBAR_TROUGH_VERTICAL:
+      style = CreateChildCSSNode(GTK_STYLE_CLASS_TROUGH,
+                                 MOZ_GTK_SCROLLBAR_CONTENTS_VERTICAL);
+      break;
+    case MOZ_GTK_SCROLLBAR_THUMB_VERTICAL:
+      style = CreateChildCSSNode(GTK_STYLE_CLASS_SLIDER,
+                                 MOZ_GTK_SCROLLBAR_TROUGH_VERTICAL);
+      break;
+    case MOZ_GTK_RADIOBUTTON:
+      style = CreateChildCSSNode(GTK_STYLE_CLASS_RADIO,
+                                 MOZ_GTK_RADIOBUTTON_CONTAINER);
+      break;
+    case MOZ_GTK_CHECKBUTTON:
+      style = CreateChildCSSNode(GTK_STYLE_CLASS_CHECK,
+                                 MOZ_GTK_CHECKBUTTON_CONTAINER);
+      break;
+    case MOZ_GTK_PROGRESS_TROUGH:
+      /* Progress bar background (trough) */
+      style = CreateChildCSSNode(GTK_STYLE_CLASS_TROUGH, MOZ_GTK_PROGRESSBAR);
+      break;
+    case MOZ_GTK_PROGRESS_CHUNK:
+      style = CreateChildCSSNode("progress", MOZ_GTK_PROGRESS_TROUGH);
+      break;
+    case MOZ_GTK_SPINBUTTON_ENTRY:
+      // TODO - create from CSS node
+      style =
+          CreateSubStyleWithClass(MOZ_GTK_SPINBUTTON, GTK_STYLE_CLASS_ENTRY);
+      break;
+    case MOZ_GTK_SCROLLED_WINDOW:
+      // TODO - create from CSS node
+      style = CreateSubStyleWithClass(MOZ_GTK_SCROLLED_WINDOW,
+                                      GTK_STYLE_CLASS_FRAME);
+      break;
+    case MOZ_GTK_TEXT_VIEW_TEXT_SELECTION:
+      style = CreateChildCSSNode("selection", MOZ_GTK_TEXT_VIEW_TEXT);
+      break;
+    case MOZ_GTK_TEXT_VIEW_TEXT:
+    case MOZ_GTK_RESIZER:
+      style = CreateChildCSSNode("text", MOZ_GTK_TEXT_VIEW);
+      if (aNodeType == MOZ_GTK_RESIZER) {
+        // The "grip" class provides the correct builtin icon from
+        // gtk_render_handle().  The icon is drawn with shaded variants of
+        // the background color, and so a transparent background would lead to
+        // a transparent resizer.  gtk_render_handle() also uses the
+        // background color to draw a background, and so this style otherwise
+        // matches what is used in GtkTextView to match the background with
+        // textarea elements.
+        GdkRGBA color;
+        gtk_style_context_get_background_color(style, GTK_STATE_FLAG_NORMAL,
+                                               &color);
+        if (color.alpha == 0.0) {
+          g_object_unref(style);
+          style = CreateStyleForWidget(gtk_text_view_new(),
+                                       MOZ_GTK_SCROLLED_WINDOW);
+        }
+        gtk_style_context_add_class(style, GTK_STYLE_CLASS_GRIP);
+      }
+      break;
+    case MOZ_GTK_FRAME_BORDER:
+      style = CreateChildCSSNode("border", MOZ_GTK_FRAME);
+      break;
+    case MOZ_GTK_TREEVIEW_VIEW:
+      // TODO - create from CSS node
+      style = CreateSubStyleWithClass(MOZ_GTK_TREEVIEW, GTK_STYLE_CLASS_VIEW);
+      break;
+    case MOZ_GTK_TREEVIEW_EXPANDER:
+      // TODO - create from CSS node
+      style =
+          CreateSubStyleWithClass(MOZ_GTK_TREEVIEW, GTK_STYLE_CLASS_EXPANDER);
+      break;
+    case MOZ_GTK_SPLITTER_SEPARATOR_HORIZONTAL:
+      style = CreateChildCSSNode("separator", MOZ_GTK_SPLITTER_HORIZONTAL);
+      break;
+    case MOZ_GTK_SPLITTER_SEPARATOR_VERTICAL:
+      style = CreateChildCSSNode("separator", MOZ_GTK_SPLITTER_VERTICAL);
+      break;
+    case MOZ_GTK_SCALE_CONTENTS_HORIZONTAL:
+      style = CreateChildCSSNode("contents", MOZ_GTK_SCALE_HORIZONTAL);
+      break;
+    case MOZ_GTK_SCALE_CONTENTS_VERTICAL:
+      style = CreateChildCSSNode("contents", MOZ_GTK_SCALE_VERTICAL);
+      break;
+    case MOZ_GTK_SCALE_TROUGH_HORIZONTAL:
+      style = CreateChildCSSNode(GTK_STYLE_CLASS_TROUGH,
+                                 MOZ_GTK_SCALE_CONTENTS_HORIZONTAL);
+      break;
+    case MOZ_GTK_SCALE_TROUGH_VERTICAL:
+      style = CreateChildCSSNode(GTK_STYLE_CLASS_TROUGH,
+                                 MOZ_GTK_SCALE_CONTENTS_VERTICAL);
+      break;
+    case MOZ_GTK_SCALE_THUMB_HORIZONTAL:
+      style = CreateChildCSSNode(GTK_STYLE_CLASS_SLIDER,
+                                 MOZ_GTK_SCALE_TROUGH_HORIZONTAL);
+      break;
+    case MOZ_GTK_SCALE_THUMB_VERTICAL:
+      style = CreateChildCSSNode(GTK_STYLE_CLASS_SLIDER,
+                                 MOZ_GTK_SCALE_TROUGH_VERTICAL);
+      break;
+    case MOZ_GTK_TAB_TOP: {
+      // TODO - create from CSS node
+      style = CreateSubStyleWithClass(MOZ_GTK_NOTEBOOK, GTK_STYLE_CLASS_TOP);
+      gtk_style_context_add_region(style, GTK_STYLE_REGION_TAB,
+                                   static_cast<GtkRegionFlags>(0));
+      break;
+    }
+    case MOZ_GTK_TAB_BOTTOM: {
+      // TODO - create from CSS node
+      style = CreateSubStyleWithClass(MOZ_GTK_NOTEBOOK, GTK_STYLE_CLASS_BOTTOM);
+      gtk_style_context_add_region(style, GTK_STYLE_REGION_TAB,
+                                   static_cast<GtkRegionFlags>(0));
+      break;
+    }
+    case MOZ_GTK_NOTEBOOK:
+    case MOZ_GTK_NOTEBOOK_HEADER:
+    case MOZ_GTK_TABPANELS:
+    case MOZ_GTK_TAB_SCROLLARROW: {
+      // TODO - create from CSS node
+      GtkWidget* widget = GetWidget(MOZ_GTK_NOTEBOOK);
+      return gtk_widget_get_style_context(widget);
+    }
+    case MOZ_GTK_WINDOW_DECORATION: {
+      GtkStyleContext* parentStyle =
+          CreateSubStyleWithClass(MOZ_GTK_WINDOW, "csd");
+      style = CreateCSSNode("decoration", parentStyle);
+      g_object_unref(parentStyle);
+      break;
+    }
+    case MOZ_GTK_WINDOW_DECORATION_SOLID: {
+      GtkStyleContext* parentStyle =
+          CreateSubStyleWithClass(MOZ_GTK_WINDOW, "solid-csd");
+      style = CreateCSSNode("decoration", parentStyle);
+      g_object_unref(parentStyle);
+      break;
+    }
+    default:
+      return GetWidgetRootStyle(aNodeType);
+  }
+
+  MOZ_ASSERT(style, "missing style context for node type");
+  sStyleStorage[aNodeType] = style;
+  return style;
+}
+
+/* GetWidgetStyleInternal is used by Gtk < 3.20 */
+static GtkStyleContext* GetWidgetStyleInternal(WidgetNodeType aNodeType) {
+  GtkStyleContext* style = sStyleStorage[aNodeType];
+  if (style) return style;
+
+  switch (aNodeType) {
+    case MOZ_GTK_SCROLLBAR_TROUGH_VERTICAL:
+      style = CreateSubStyleWithClass(MOZ_GTK_SCROLLBAR_VERTICAL,
+                                      GTK_STYLE_CLASS_TROUGH);
+      break;
+    case MOZ_GTK_SCROLLBAR_THUMB_VERTICAL:
+      style = CreateSubStyleWithClass(MOZ_GTK_SCROLLBAR_VERTICAL,
+                                      GTK_STYLE_CLASS_SLIDER);
+      break;
+    case MOZ_GTK_RADIOBUTTON:
+      style = CreateSubStyleWithClass(MOZ_GTK_RADIOBUTTON_CONTAINER,
+                                      GTK_STYLE_CLASS_RADIO);
+      break;
+    case MOZ_GTK_CHECKBUTTON:
+      style = CreateSubStyleWithClass(MOZ_GTK_CHECKBUTTON_CONTAINER,
+                                      GTK_STYLE_CLASS_CHECK);
+      break;
+    case MOZ_GTK_PROGRESS_TROUGH:
+      style =
+          CreateSubStyleWithClass(MOZ_GTK_PROGRESSBAR, GTK_STYLE_CLASS_TROUGH);
+      break;
+    case MOZ_GTK_PROGRESS_CHUNK:
+      style = CreateSubStyleWithClass(MOZ_GTK_PROGRESSBAR,
+                                      GTK_STYLE_CLASS_PROGRESSBAR);
+      gtk_style_context_remove_class(style, GTK_STYLE_CLASS_TROUGH);
+      break;
+    case MOZ_GTK_SPINBUTTON_ENTRY:
+      style =
+          CreateSubStyleWithClass(MOZ_GTK_SPINBUTTON, GTK_STYLE_CLASS_ENTRY);
+      break;
+    case MOZ_GTK_SCROLLED_WINDOW:
+      style = CreateSubStyleWithClass(MOZ_GTK_SCROLLED_WINDOW,
+                                      GTK_STYLE_CLASS_FRAME);
+      break;
+    case MOZ_GTK_TEXT_VIEW_TEXT:
+    case MOZ_GTK_RESIZER:
+      // GTK versions prior to 3.20 do not have the view class on the root
+      // node, but add this to determine the background for the text window.
+      style = CreateSubStyleWithClass(MOZ_GTK_TEXT_VIEW, GTK_STYLE_CLASS_VIEW);
+      if (aNodeType == MOZ_GTK_RESIZER) {
+        // The "grip" class provides the correct builtin icon from
+        // gtk_render_handle().  The icon is drawn with shaded variants of
+        // the background color, and so a transparent background would lead to
+        // a transparent resizer.  gtk_render_handle() also uses the
+        // background color to draw a background, and so this style otherwise
+        // matches MOZ_GTK_TEXT_VIEW_TEXT to match the background with
+        // textarea elements.  GtkTextView creates a separate text window and
+        // so the background should not be transparent.
+        gtk_style_context_add_class(style, GTK_STYLE_CLASS_GRIP);
+      }
+      break;
+    case MOZ_GTK_FRAME_BORDER:
+      return GetWidgetRootStyle(MOZ_GTK_FRAME);
+    case MOZ_GTK_TREEVIEW_VIEW:
+      style = CreateSubStyleWithClass(MOZ_GTK_TREEVIEW, GTK_STYLE_CLASS_VIEW);
+      break;
+    case MOZ_GTK_TREEVIEW_EXPANDER:
+      style =
+          CreateSubStyleWithClass(MOZ_GTK_TREEVIEW, GTK_STYLE_CLASS_EXPANDER);
+      break;
+    case MOZ_GTK_SPLITTER_SEPARATOR_HORIZONTAL:
+      style = CreateSubStyleWithClass(MOZ_GTK_SPLITTER_HORIZONTAL,
+                                      GTK_STYLE_CLASS_PANE_SEPARATOR);
+      break;
+    case MOZ_GTK_SPLITTER_SEPARATOR_VERTICAL:
+      style = CreateSubStyleWithClass(MOZ_GTK_SPLITTER_VERTICAL,
+                                      GTK_STYLE_CLASS_PANE_SEPARATOR);
+      break;
+    case MOZ_GTK_SCALE_TROUGH_HORIZONTAL:
+      style = CreateSubStyleWithClass(MOZ_GTK_SCALE_HORIZONTAL,
+                                      GTK_STYLE_CLASS_TROUGH);
+      break;
+    case MOZ_GTK_SCALE_TROUGH_VERTICAL:
+      style = CreateSubStyleWithClass(MOZ_GTK_SCALE_VERTICAL,
+                                      GTK_STYLE_CLASS_TROUGH);
+      break;
+    case MOZ_GTK_SCALE_THUMB_HORIZONTAL:
+      style = CreateSubStyleWithClass(MOZ_GTK_SCALE_HORIZONTAL,
+                                      GTK_STYLE_CLASS_SLIDER);
+      break;
+    case MOZ_GTK_SCALE_THUMB_VERTICAL:
+      style = CreateSubStyleWithClass(MOZ_GTK_SCALE_VERTICAL,
+                                      GTK_STYLE_CLASS_SLIDER);
+      break;
+    case MOZ_GTK_TAB_TOP:
+      style = CreateSubStyleWithClass(MOZ_GTK_NOTEBOOK, GTK_STYLE_CLASS_TOP);
+      gtk_style_context_add_region(style, GTK_STYLE_REGION_TAB,
+                                   static_cast<GtkRegionFlags>(0));
+      break;
+    case MOZ_GTK_TAB_BOTTOM:
+      style = CreateSubStyleWithClass(MOZ_GTK_NOTEBOOK, GTK_STYLE_CLASS_BOTTOM);
+      gtk_style_context_add_region(style, GTK_STYLE_REGION_TAB,
+                                   static_cast<GtkRegionFlags>(0));
+      break;
+    case MOZ_GTK_NOTEBOOK:
+    case MOZ_GTK_NOTEBOOK_HEADER:
+    case MOZ_GTK_TABPANELS:
+    case MOZ_GTK_TAB_SCROLLARROW: {
+      GtkWidget* widget = GetWidget(MOZ_GTK_NOTEBOOK);
+      return gtk_widget_get_style_context(widget);
+    }
+    default:
+      return GetWidgetRootStyle(aNodeType);
+  }
+
+  MOZ_ASSERT(style);
+  sStyleStorage[aNodeType] = style;
+  return style;
+}
+
+void ResetWidgetCache() {
+  for (int i = 0; i < MOZ_GTK_WIDGET_NODE_COUNT; i++) {
+    if (sStyleStorage[i]) g_object_unref(sStyleStorage[i]);
+  }
+  mozilla::PodArrayZero(sStyleStorage);
+
+  gCSDStyle = CSDStyle::Unknown;
+
+  /* This will destroy all of our widgets */
+  if (sWidgetStorage[MOZ_GTK_WINDOW]) {
+    gtk_widget_destroy(sWidgetStorage[MOZ_GTK_WINDOW]);
+  }
+  if (sWidgetStorage[MOZ_GTK_HEADERBAR_WINDOW]) {
+    gtk_widget_destroy(sWidgetStorage[MOZ_GTK_HEADERBAR_WINDOW]);
+  }
+  if (sWidgetStorage[MOZ_GTK_HEADERBAR_WINDOW_MAXIMIZED]) {
+    gtk_widget_destroy(sWidgetStorage[MOZ_GTK_HEADERBAR_WINDOW_MAXIMIZED]);
+  }
+
+  /* Clear already freed arrays */
+  mozilla::PodArrayZero(sWidgetStorage);
+}
+
+GtkStyleContext* GetStyleContext(WidgetNodeType aNodeType, int aScale,
+                                 GtkTextDirection aDirection,
+                                 GtkStateFlags aStateFlags) {
+  GtkStyleContext* style;
+  if (gtk_check_version(3, 20, 0) != nullptr) {
+    style = GetWidgetStyleInternal(aNodeType);
+  } else {
+    style = GetCssNodeStyleInternal(aNodeType);
+    StyleContextSetScale(style, aScale);
+  }
+  bool stateChanged = false;
+  bool stateHasDirection = gtk_get_minor_version() >= 8;
+  GtkStateFlags oldState = gtk_style_context_get_state(style);
+  MOZ_ASSERT(!(aStateFlags & (STATE_FLAG_DIR_LTR | STATE_FLAG_DIR_RTL)));
+  unsigned newState = aStateFlags;
+  if (stateHasDirection) {
+    switch (aDirection) {
+      case GTK_TEXT_DIR_LTR:
+        newState |= STATE_FLAG_DIR_LTR;
+        break;
+      case GTK_TEXT_DIR_RTL:
+        newState |= STATE_FLAG_DIR_RTL;
+        break;
+      default:
+        MOZ_FALLTHROUGH_ASSERT("Bad GtkTextDirection");
+      case GTK_TEXT_DIR_NONE:
+        // GtkWidget uses a default direction if neither is explicitly
+        // specified, but here DIR_NONE is interpreted as meaning the
+        // direction is not important, so don't change the direction
+        // unnecessarily.
+        newState |= oldState & (STATE_FLAG_DIR_LTR | STATE_FLAG_DIR_RTL);
+    }
+  } else if (aDirection != GTK_TEXT_DIR_NONE) {
+    GtkTextDirection oldDirection = gtk_style_context_get_direction(style);
+    if (aDirection != oldDirection) {
+      gtk_style_context_set_direction(style, aDirection);
+      stateChanged = true;
+    }
+  }
+  if (oldState != newState) {
+    gtk_style_context_set_state(style, static_cast<GtkStateFlags>(newState));
+    stateChanged = true;
+  }
+  // This invalidate is necessary for unsaved style contexts from GtkWidgets
+  // in pre-3.18 GTK, because automatic invalidation of such contexts
+  // was delayed until a resize event runs.
+  //
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=1272194#c7
+  //
+  // Avoid calling invalidate on contexts that are not owned and constructed
+  // by widgets to avoid performing build_properties() (in 3.16 stylecontext.c)
+  // unnecessarily early.
+  if (stateChanged && sWidgetStorage[aNodeType]) {
+    gtk_style_context_invalidate(style);
+  }
+  return style;
+}
+
+GtkStyleContext* CreateStyleContextWithStates(WidgetNodeType aNodeType,
+                                              int aScale,
+                                              GtkTextDirection aDirection,
+                                              GtkStateFlags aStateFlags) {
+  GtkStyleContext* style =
+      GetStyleContext(aNodeType, aScale, aDirection, aStateFlags);
+  GtkWidgetPath* path = gtk_widget_path_copy(gtk_style_context_get_path(style));
+
+  static auto sGtkWidgetPathIterGetState =
+      (GtkStateFlags(*)(const GtkWidgetPath*, gint))dlsym(
+          RTLD_DEFAULT, "gtk_widget_path_iter_get_state");
+  static auto sGtkWidgetPathIterSetState =
+      (void (*)(GtkWidgetPath*, gint, GtkStateFlags))dlsym(
+          RTLD_DEFAULT, "gtk_widget_path_iter_set_state");
+
+  int pathLength = gtk_widget_path_length(path);
+  for (int i = 0; i < pathLength; i++) {
+    unsigned state = aStateFlags | sGtkWidgetPathIterGetState(path, i);
+    sGtkWidgetPathIterSetState(path, i, GtkStateFlags(state));
+  }
+
+  style = gtk_style_context_new();
+  gtk_style_context_set_path(style, path);
+  gtk_widget_path_unref(path);
+
+  return style;
+}
+
+void StyleContextSetScale(GtkStyleContext* style, gint aScaleFactor) {
+  // Support HiDPI styles on Gtk 3.20+
+  static auto sGtkStyleContextSetScalePtr =
+      (void (*)(GtkStyleContext*, gint))dlsym(RTLD_DEFAULT,
+                                              "gtk_style_context_set_scale");
+  if (sGtkStyleContextSetScalePtr && style) {
+    sGtkStyleContextSetScalePtr(style, aScaleFactor);
+  }
+}
+
+bool HeaderBarShouldDrawContainer(WidgetNodeType aNodeType) {
+  MOZ_ASSERT(aNodeType == MOZ_GTK_HEADER_BAR ||
+             aNodeType == MOZ_GTK_HEADER_BAR_MAXIMIZED);
+  mozilla::Unused << GetWidget(aNodeType);
+  return aNodeType == MOZ_GTK_HEADER_BAR
+             ? gHeaderBarShouldDrawContainer
+             : gMaximizedHeaderBarShouldDrawContainer;
+}
+
+gint GetBorderRadius(GtkStyleContext* aStyle) {
+  GValue value = G_VALUE_INIT;
+  // NOTE(emilio): In an ideal world, we'd query the two longhands
+  // (border-top-left-radius and border-top-right-radius) separately. However,
+  // that doesn't work (GTK rejects the query with:
+  //
+  //   Style property "border-top-left-radius" is not gettable
+  //
+  // However! Getting border-radius does work, and it does return the
+  // border-top-left-radius as a gint:
+  //
+  //   https://docs.gtk.org/gtk3/const.STYLE_PROPERTY_BORDER_RADIUS.html
+  //   https://gitlab.gnome.org/GNOME/gtk/-/blob/gtk-3-20/gtk/gtkcssshorthandpropertyimpl.c#L961-977
+  //
+  // So we abuse this fact, and make the assumption here that the
+  // border-top-{left,right}-radius are the same, and roll with it.
+  gtk_style_context_get_property(aStyle, "border-radius", GTK_STATE_FLAG_NORMAL,
+                                 &value);
+  gint result = 0;
+  auto type = G_VALUE_TYPE(&value);
+  if (type == G_TYPE_INT) {
+    result = g_value_get_int(&value);
+  } else {
+    NS_WARNING(nsPrintfCString("Unknown value type %lu for border-radius", type)
+                   .get());
+  }
+  g_value_unset(&value);
+  return result;
+}
diff --git a/widget/gtk/WidgetStyleCache.h b/widget/gtk/WidgetStyleCache.h
new file mode 100644
index 0000000000..f38b75fae6
--- /dev/null
+++ b/widget/gtk/WidgetStyleCache.h
@@ -0,0 +1,63 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WidgetStyleCache_h
+#define WidgetStyleCache_h
+
+#include <gtk/gtk.h>
+#include "gtkdrawing.h"
+
+GtkWidget* GetWidget(WidgetNodeType aNodeType);
+
+cairo_surface_t* GetWidgetIconSurface(GtkWidget* aWidgetIcon, int aScale);
+
+/*
+ * Return a new style context based on aWidget, as a child of aParentStyle.
+ * If aWidget still has a floating reference, then it is sunk and released.
+ */
+GtkStyleContext* CreateStyleForWidget(GtkWidget* aWidget,
+                                      GtkStyleContext* aParentStyle);
+
+GtkStyleContext* CreateCSSNode(const char* aName, GtkStyleContext* aParentStyle,
+                               GType aType = G_TYPE_NONE);
+
+/*
+ * Returns a pointer to a style context for the specified node and state.
+ * aStateFlags is applied only to last widget in css style path,
+ * for instance GetStyleContext(MOZ_GTK_BUTTON, .., GTK_STATE_FLAG_HOVER)
+ * you get "window button:hover" css selector.
+ * If you want aStateFlags applied to all path elements use
+ * CreateStyleContextWithStates().
+ *
+ * The context is owned by WidgetStyleCache. Do not unref.
+ */
+GtkStyleContext* GetStyleContext(
+    WidgetNodeType aNodeType, int aScale = 1,
+    GtkTextDirection aDirection = GTK_TEXT_DIR_NONE,
+    GtkStateFlags aStateFlags = GTK_STATE_FLAG_NORMAL);
+
+/*
+ * Returns a pointer to a style context for the specified node
+ * and state applied to all elements at widget style path.
+ *
+ * The context is owned by caller and must be released by g_object_unref().
+ */
+GtkStyleContext* CreateStyleContextWithStates(
+    WidgetNodeType aNodeType, int aScale = 1,
+    GtkTextDirection aDirection = GTK_TEXT_DIR_NONE,
+    GtkStateFlags aStateFlags = GTK_STATE_FLAG_NORMAL);
+
+void ResetWidgetCache();
+
+bool IsSolidCSDStyleUsed();
+
+void StyleContextSetScale(GtkStyleContext* style, gint aScaleFactor);
+
+gint GetBorderRadius(GtkStyleContext* aStyle);
+
+bool HeaderBarShouldDrawContainer(WidgetNodeType);
+
+#endif  // WidgetStyleCache_h
diff --git a/widget/gtk/WidgetTraceEvent.cpp b/widget/gtk/WidgetTraceEvent.cpp
new file mode 100644
index 0000000000..161e5302cc
--- /dev/null
+++ b/widget/gtk/WidgetTraceEvent.cpp
@@ -0,0 +1,68 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/WidgetTraceEvent.h"
+
+#include <glib.h>
+#include <mozilla/CondVar.h>
+#include <mozilla/Mutex.h>
+#include <stdio.h>
+
+using mozilla::CondVar;
+using mozilla::Mutex;
+using mozilla::MutexAutoLock;
+
+namespace {
+
+Mutex* sMutex = nullptr;
+CondVar* sCondVar = nullptr;
+bool sTracerProcessed = false;
+
+// This function is called from the main (UI) thread.
+gboolean TracerCallback(gpointer data) {
+  mozilla::SignalTracerThread();
+  return FALSE;
+}
+
+}  // namespace
+
+namespace mozilla {
+
+bool InitWidgetTracing() {
+  sMutex = new Mutex("Event tracer thread mutex");
+  sCondVar = new CondVar(*sMutex, "Event tracer thread condvar");
+  return true;
+}
+
+void CleanUpWidgetTracing() {
+  delete sMutex;
+  delete sCondVar;
+  sMutex = nullptr;
+  sCondVar = nullptr;
+}
+
+// This function is called from the background tracer thread.
+bool FireAndWaitForTracerEvent() {
+  MOZ_ASSERT(sMutex && sCondVar, "Tracing not initialized!");
+
+  // Send a default-priority idle event through the
+  // event loop, and wait for it to finish.
+  MutexAutoLock lock(*sMutex);
+  MOZ_ASSERT(!sTracerProcessed, "Tracer synchronization state is wrong");
+  g_idle_add_full(G_PRIORITY_DEFAULT, TracerCallback, nullptr, nullptr);
+  while (!sTracerProcessed) sCondVar->Wait();
+  sTracerProcessed = false;
+  return true;
+}
+
+void SignalTracerThread() {
+  if (!sMutex || !sCondVar) return;
+  MutexAutoLock lock(*sMutex);
+  if (!sTracerProcessed) {
+    sTracerProcessed = true;
+    sCondVar->Notify();
+  }
+}
+
+}  // namespace mozilla
diff --git a/widget/gtk/WidgetUtilsGtk.cpp b/widget/gtk/WidgetUtilsGtk.cpp
new file mode 100644
index 0000000000..2ce81dedb7
--- /dev/null
+++ b/widget/gtk/WidgetUtilsGtk.cpp
@@ -0,0 +1,500 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WidgetUtilsGtk.h"
+
+#include "MainThreadUtils.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/UniquePtr.h"
+#include "nsReadableUtils.h"
+#include "nsString.h"
+#include "nsStringFwd.h"
+#include "nsWindow.h"
+#include "nsIGfxInfo.h"
+#include "mozilla/Components.h"
+#include "nsCOMPtr.h"
+#include "nsIProperties.h"
+#include "nsIFile.h"
+#include "nsXULAppAPI.h"
+#include "nsXPCOMCID.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsString.h"
+#include "nsGtkKeyUtils.h"
+#include "nsGtkUtils.h"
+
+#include <gtk/gtk.h>
+#include <dlfcn.h>
+#include <glib.h>
+
+#undef LOGW
+#ifdef MOZ_LOGGING
+#  include "mozilla/Logging.h"
+extern mozilla::LazyLogModule gWidgetLog;
+#  define LOGW(...) MOZ_LOG(gWidgetLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#else
+#  define LOGW(...)
+#endif /* MOZ_LOGGING */
+
+namespace mozilla::widget {
+
+int32_t WidgetUtilsGTK::IsTouchDeviceSupportPresent() {
+  int32_t result = 0;
+  GdkDisplay* display = gdk_display_get_default();
+  if (!display) {
+    return 0;
+  }
+
+  GdkDeviceManager* manager = gdk_display_get_device_manager(display);
+  if (!manager) {
+    return 0;
+  }
+
+  GList* devices =
+      gdk_device_manager_list_devices(manager, GDK_DEVICE_TYPE_SLAVE);
+  GList* list = devices;
+
+  while (devices) {
+    GdkDevice* device = static_cast<GdkDevice*>(devices->data);
+    if (gdk_device_get_source(device) == GDK_SOURCE_TOUCHSCREEN) {
+      result = 1;
+      break;
+    }
+    devices = devices->next;
+  }
+
+  if (list) {
+    g_list_free(list);
+  }
+
+  return result;
+}
+
+bool IsMainWindowTransparent() {
+  return nsWindow::IsToplevelWindowTransparent();
+}
+
+// We avoid linking gdk_*_display_get_type directly in order to avoid a runtime
+// dependency on GTK built with both backends. Other X11- and Wayland-specific
+// functions get stubbed out by libmozgtk and crash when called, but those
+// should only be called when the matching backend is already in use.
+
+bool GdkIsWaylandDisplay(GdkDisplay* display) {
+  static auto sGdkWaylandDisplayGetType =
+      (GType(*)())dlsym(RTLD_DEFAULT, "gdk_wayland_display_get_type");
+  return sGdkWaylandDisplayGetType &&
+         G_TYPE_CHECK_INSTANCE_TYPE(display, sGdkWaylandDisplayGetType());
+}
+
+bool GdkIsX11Display(GdkDisplay* display) {
+  static auto sGdkX11DisplayGetType =
+      (GType(*)())dlsym(RTLD_DEFAULT, "gdk_x11_display_get_type");
+  return sGdkX11DisplayGetType &&
+         G_TYPE_CHECK_INSTANCE_TYPE(display, sGdkX11DisplayGetType());
+}
+
+bool IsXWaylandProtocol() {
+  static bool isXwayland = [] {
+    return !GdkIsWaylandDisplay() && !!getenv("WAYLAND_DISPLAY");
+  }();
+  return isXwayland;
+}
+
+bool GdkIsWaylandDisplay() {
+  static bool isWaylandDisplay = gdk_display_get_default() &&
+                                 GdkIsWaylandDisplay(gdk_display_get_default());
+  return isWaylandDisplay;
+}
+
+bool GdkIsX11Display() {
+  static bool isX11Display = gdk_display_get_default()
+                                 ? GdkIsX11Display(gdk_display_get_default())
+                                 : false;
+  return isX11Display;
+}
+
+GdkDevice* GdkGetPointer() {
+  GdkDisplay* display = gdk_display_get_default();
+  GdkDeviceManager* deviceManager = gdk_display_get_device_manager(display);
+  return gdk_device_manager_get_client_pointer(deviceManager);
+}
+
+static GdkEvent* sLastMousePressEvent = nullptr;
+GdkEvent* GetLastMousePressEvent() { return sLastMousePressEvent; }
+
+void SetLastMousePressEvent(GdkEvent* aEvent) {
+  if (sLastMousePressEvent) {
+    GUniquePtr<GdkEvent> event(sLastMousePressEvent);
+    sLastMousePressEvent = nullptr;
+  }
+  if (!aEvent) {
+    return;
+  }
+  GUniquePtr<GdkEvent> event(gdk_event_copy(aEvent));
+  sLastMousePressEvent = event.release();
+}
+
+bool IsRunningUnderSnap() { return !!GetSnapInstanceName(); }
+
+bool IsRunningUnderFlatpak() {
+  // https://gitlab.gnome.org/GNOME/gtk/-/blob/4300a5c609306ce77cbc8a3580c19201dccd8d13/gdk/gdk.c#L472
+  static bool sRunning = [] {
+    return g_file_test("/.flatpak-info", G_FILE_TEST_EXISTS);
+  }();
+  return sRunning;
+}
+
+bool IsPackagedAppFileExists() {
+  static bool sRunning = [] {
+    nsresult rv;
+    nsCString path;
+    nsCOMPtr<nsIFile> file;
+    nsCOMPtr<nsIProperties> directoryService;
+
+    directoryService = do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID);
+    NS_ENSURE_TRUE(directoryService, FALSE);
+
+    rv = directoryService->Get(NS_GRE_DIR, NS_GET_IID(nsIFile),
+                               getter_AddRefs(file));
+    NS_ENSURE_SUCCESS(rv, FALSE);
+
+    rv = file->AppendNative("is-packaged-app"_ns);
+    NS_ENSURE_SUCCESS(rv, FALSE);
+
+    rv = file->GetNativePath(path);
+    NS_ENSURE_SUCCESS(rv, FALSE);
+
+    return g_file_test(path.get(), G_FILE_TEST_EXISTS);
+  }();
+  return sRunning;
+}
+
+const char* GetSnapInstanceName() {
+  static const char* sInstanceName = []() -> const char* {
+    const char* snapName = g_getenv("SNAP_NAME");
+    if (!snapName) {
+      return nullptr;
+    }
+    if (g_strcmp0(snapName, MOZ_APP_NAME)) {
+      return nullptr;
+    }
+    // Intentionally leaked, as keeping a pointer to the environment forever
+    // is a bit suspicious.
+    if (const char* instanceName = g_getenv("SNAP_INSTANCE_NAME")) {
+      return g_strdup(instanceName);
+    }
+    // Instance name didn't exist for snapd <= 2.35:
+    return g_strdup(snapName);
+  }();
+  return sInstanceName;
+}
+
+bool ShouldUsePortal(PortalKind aPortalKind) {
+  static bool sPortalEnv = [] {
+    if (IsRunningUnderFlatpakOrSnap()) {
+      return true;
+    }
+    const char* portalEnvString = g_getenv("GTK_USE_PORTAL");
+    return portalEnvString && atoi(portalEnvString) != 0;
+  }();
+
+  bool autoBehavior = sPortalEnv;
+  const int32_t pref = [&] {
+    switch (aPortalKind) {
+      case PortalKind::FilePicker:
+        return StaticPrefs::widget_use_xdg_desktop_portal_file_picker();
+      case PortalKind::MimeHandler:
+        // Mime portal breaks default browser handling, see bug 1516290.
+        autoBehavior = IsRunningUnderFlatpakOrSnap();
+        return StaticPrefs::widget_use_xdg_desktop_portal_mime_handler();
+      case PortalKind::Settings:
+        autoBehavior = true;
+        return StaticPrefs::widget_use_xdg_desktop_portal_settings();
+      case PortalKind::Location:
+        return StaticPrefs::widget_use_xdg_desktop_portal_location();
+      case PortalKind::OpenUri:
+        return StaticPrefs::widget_use_xdg_desktop_portal_open_uri();
+    }
+    return 2;
+  }();
+
+  switch (pref) {
+    case 0:
+      return false;
+    case 1:
+      return true;
+    default:
+      return autoBehavior;
+  }
+}
+
+nsTArray<nsCString> ParseTextURIList(const nsACString& aData) {
+  UniquePtr<char[]> data(ToNewCString(aData));
+  gchar** uris = g_uri_list_extract_uris(data.get());
+
+  nsTArray<nsCString> result;
+  for (size_t i = 0; i < g_strv_length(uris); i++) {
+    result.AppendElement(nsCString(uris[i]));
+  }
+
+  g_strfreev(uris);
+  return result;
+}
+
+#ifdef MOZ_WAYLAND
+static gboolean token_failed(gpointer aData);
+
+class XDGTokenRequest {
+ public:
+  void SetTokenID(const char* aTokenID) {
+    LOGW("RequestWaylandFocusPromise() SetTokenID %s", aTokenID);
+    mTransferPromise->Resolve(aTokenID, __func__);
+  }
+  void Cancel() {
+    LOGW("RequestWaylandFocusPromise() canceled");
+    mTransferPromise->Reject(false, __func__);
+    mActivationTimeoutID = 0;
+  }
+
+  XDGTokenRequest(xdg_activation_token_v1* aXdgToken,
+                  RefPtr<FocusRequestPromise::Private> aTransferPromise)
+      : mXdgToken(aXdgToken), mTransferPromise(std::move(aTransferPromise)) {
+    mActivationTimeoutID =
+        g_timeout_add(sActivationTimeout, token_failed, this);
+  }
+  ~XDGTokenRequest() {
+    MozClearPointer(mXdgToken, xdg_activation_token_v1_destroy);
+    if (mActivationTimeoutID) {
+      g_source_remove(mActivationTimeoutID);
+    }
+  }
+
+ private:
+  xdg_activation_token_v1* mXdgToken;
+  RefPtr<FocusRequestPromise::Private> mTransferPromise;
+  guint mActivationTimeoutID;
+  // Reject FocusRequestPromise if we don't get XDG token in 0.5 sec.
+  static constexpr int sActivationTimeout = 500;
+};
+
+// Failed to get token in time
+static gboolean token_failed(gpointer data) {
+  UniquePtr<XDGTokenRequest> request(static_cast<XDGTokenRequest*>(data));
+  request->Cancel();
+  return false;
+}
+
+// We've got activation token from Wayland compositor so it's time to use it.
+static void token_done(gpointer data, struct xdg_activation_token_v1* provider,
+                       const char* tokenID) {
+  UniquePtr<XDGTokenRequest> request(static_cast<XDGTokenRequest*>(data));
+  request->SetTokenID(tokenID);
+}
+
+static const struct xdg_activation_token_v1_listener token_listener = {
+    token_done,
+};
+#endif
+
+RefPtr<FocusRequestPromise> RequestWaylandFocusPromise() {
+#ifdef MOZ_WAYLAND
+  if (!GdkIsWaylandDisplay() || !KeymapWrapper::GetSeat()) {
+    LOGW("RequestWaylandFocusPromise() failed.");
+    return nullptr;
+  }
+
+  RefPtr<nsWindow> sourceWindow = nsWindow::GetFocusedWindow();
+  if (!sourceWindow || sourceWindow->IsDestroyed()) {
+    LOGW("RequestWaylandFocusPromise() missing source window");
+    return nullptr;
+  }
+
+  xdg_activation_v1* xdg_activation = WaylandDisplayGet()->GetXdgActivation();
+  if (!xdg_activation) {
+    LOGW("RequestWaylandFocusPromise() missing xdg_activation");
+    return nullptr;
+  }
+
+  wl_surface* focusSurface;
+  uint32_t focusSerial;
+  KeymapWrapper::GetFocusInfo(&focusSurface, &focusSerial);
+  if (!focusSurface) {
+    LOGW("RequestWaylandFocusPromise() missing focusSurface");
+    return nullptr;
+  }
+
+  GdkWindow* gdkWindow = sourceWindow->GetToplevelGdkWindow();
+  if (!gdkWindow) {
+    return nullptr;
+  }
+  wl_surface* surface = gdk_wayland_window_get_wl_surface(gdkWindow);
+  if (focusSurface != surface) {
+    LOGW("RequestWaylandFocusPromise() missing wl_surface");
+    return nullptr;
+  }
+
+  RefPtr<FocusRequestPromise::Private> transferPromise =
+      new FocusRequestPromise::Private(__func__);
+
+  xdg_activation_token_v1* aXdgToken =
+      xdg_activation_v1_get_activation_token(xdg_activation);
+  xdg_activation_token_v1_add_listener(
+      aXdgToken, &token_listener,
+      new XDGTokenRequest(aXdgToken, transferPromise));
+  xdg_activation_token_v1_set_serial(aXdgToken, focusSerial,
+                                     KeymapWrapper::GetSeat());
+  xdg_activation_token_v1_set_surface(aXdgToken, focusSurface);
+  xdg_activation_token_v1_commit(aXdgToken);
+
+  LOGW("RequestWaylandFocusPromise() XDG Token sent");
+
+  return transferPromise.forget();
+#else  // !defined(MOZ_WAYLAND)
+  return nullptr;
+#endif
+}
+
+// https://specifications.freedesktop.org/wm-spec/1.3/ar01s05.html
+static nsCString GetWindowManagerName() {
+  if (!GdkIsX11Display()) {
+    return {};
+  }
+
+#ifdef MOZ_X11
+  Display* xdisplay = gdk_x11_get_default_xdisplay();
+  Window root_win =
+      GDK_WINDOW_XID(gdk_screen_get_root_window(gdk_screen_get_default()));
+
+  int actual_format_return;
+  Atom actual_type_return;
+  unsigned long nitems_return;
+  unsigned long bytes_after_return;
+  unsigned char* prop_return = nullptr;
+  auto releaseXProperty = MakeScopeExit([&] {
+    if (prop_return) {
+      XFree(prop_return);
+    }
+  });
+
+  Atom property = XInternAtom(xdisplay, "_NET_SUPPORTING_WM_CHECK", true);
+  Atom req_type = XInternAtom(xdisplay, "WINDOW", true);
+  if (!property || !req_type) {
+    return {};
+  }
+  int result =
+      XGetWindowProperty(xdisplay, root_win, property,
+                         0L,                  // offset
+                         sizeof(Window) / 4,  // length
+                         false,               // delete
+                         req_type, &actual_type_return, &actual_format_return,
+                         &nitems_return, &bytes_after_return, &prop_return);
+
+  if (result != Success || bytes_after_return != 0 || nitems_return != 1) {
+    return {};
+  }
+
+  Window wmWindow = reinterpret_cast<Window*>(prop_return)[0];
+  if (!wmWindow) {
+    return {};
+  }
+
+  XFree(prop_return);
+  prop_return = nullptr;
+
+  property = XInternAtom(xdisplay, "_NET_WM_NAME", true);
+  req_type = XInternAtom(xdisplay, "UTF8_STRING", true);
+  if (!property || !req_type) {
+    return {};
+  }
+  result =
+      XGetWindowProperty(xdisplay, wmWindow, property,
+                         0L,         // offset
+                         INT32_MAX,  // length
+                         false,      // delete
+                         req_type, &actual_type_return, &actual_format_return,
+                         &nitems_return, &bytes_after_return, &prop_return);
+  if (result != Success || bytes_after_return != 0) {
+    return {};
+  }
+
+  return nsCString(reinterpret_cast<const char*>(prop_return));
+#else
+  return {};
+#endif
+}
+
+// Getting a reliable identifier is quite tricky. We try to use the standard
+// XDG_CURRENT_DESKTOP environment first, _NET_WM_NAME later, and a set of
+// legacy / non-standard environment variables otherwise.
+//
+// Documentation for some of those can be found in:
+//
+// https://wiki.archlinux.org/title/Environment_variables#Examples
+// https://wiki.archlinux.org/title/Xdg-utils#Environment_variables
+const nsCString& GetDesktopEnvironmentIdentifier() {
+  MOZ_ASSERT(NS_IsMainThread());
+  static const nsDependentCString sIdentifier = [] {
+    nsCString ident = [] {
+      auto Env = [](const char* aKey) -> const char* {
+        const char* v = getenv(aKey);
+        return v && *v ? v : nullptr;
+      };
+      if (const char* currentDesktop = Env("XDG_CURRENT_DESKTOP")) {
+        return nsCString(currentDesktop);
+      }
+      if (auto wm = GetWindowManagerName(); !wm.IsEmpty()) {
+        return wm;
+      }
+      if (const char* sessionDesktop = Env("XDG_SESSION_DESKTOP")) {
+        // This is not really standardized in freedesktop.org, but it is
+        // documented here, and should be set in systemd systems.
+        // https://www.freedesktop.org/software/systemd/man/pam_systemd.html#%24XDG_SESSION_DESKTOP
+        return nsCString(sessionDesktop);
+      }
+      // We try first the DE-specific variables, then SESSION_DESKTOP, to match
+      // the documented order in:
+      // https://wiki.archlinux.org/title/Xdg-utils#Environment_variables
+      if (getenv("GNOME_DESKTOP_SESSION_ID")) {
+        return nsCString("gnome"_ns);
+      }
+      if (getenv("KDE_FULL_SESSION")) {
+        return nsCString("kde"_ns);
+      }
+      if (getenv("MATE_DESKTOP_SESSION_ID")) {
+        return nsCString("mate"_ns);
+      }
+      if (getenv("LXQT_SESSION_CONFIG")) {
+        return nsCString("lxqt"_ns);
+      }
+      if (const char* desktopSession = Env("DESKTOP_SESSION")) {
+        // Try the legacy DESKTOP_SESSION as a last resort.
+        return nsCString(desktopSession);
+      }
+      return nsCString();
+    }();
+    ToLowerCase(ident);
+    // Intentionally put into a ToNewCString copy, rather than just making a
+    // static nsCString to avoid leakchecking errors, since we really want to
+    // leak this string.
+    return nsDependentCString(ToNewCString(ident), ident.Length());
+  }();
+  return sIdentifier;
+}
+
+bool IsGnomeDesktopEnvironment() {
+  static bool sIsGnome =
+      !!FindInReadable("gnome"_ns, GetDesktopEnvironmentIdentifier());
+  return sIsGnome;
+}
+
+bool IsKdeDesktopEnvironment() {
+  static bool sIsKde = GetDesktopEnvironmentIdentifier().EqualsLiteral("kde");
+  return sIsKde;
+}
+
+bool IsCancelledGError(GError* aGError) {
+  return g_error_matches(aGError, G_IO_ERROR, G_IO_ERROR_CANCELLED);
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/WidgetUtilsGtk.h b/widget/gtk/WidgetUtilsGtk.h
new file mode 100644
index 0000000000..ffd7425ae5
--- /dev/null
+++ b/widget/gtk/WidgetUtilsGtk.h
@@ -0,0 +1,83 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WidgetUtilsGtk_h__
+#define WidgetUtilsGtk_h__
+
+#include "nsString.h"
+#include "nsTArray.h"
+#include "mozilla/MozPromise.h"
+
+#include <stdint.h>
+
+typedef struct _GdkDisplay GdkDisplay;
+typedef struct _GdkDevice GdkDevice;
+typedef struct _GError GError;
+typedef union _GdkEvent GdkEvent;
+class nsWindow;
+
+namespace mozilla::widget {
+
+class WidgetUtilsGTK {
+ public:
+  /* See WidgetUtils::IsTouchDeviceSupportPresent(). */
+  static int32_t IsTouchDeviceSupportPresent();
+};
+
+bool IsMainWindowTransparent();
+
+bool GdkIsWaylandDisplay(GdkDisplay* display);
+bool GdkIsX11Display(GdkDisplay* display);
+
+bool GdkIsWaylandDisplay();
+bool GdkIsX11Display();
+
+bool IsXWaylandProtocol();
+
+GdkDevice* GdkGetPointer();
+
+// Sets / returns the last mouse press event we processed.
+void SetLastMousePressEvent(GdkEvent*);
+GdkEvent* GetLastMousePressEvent();
+
+// Return the snap's instance name, or null when not running as a snap.
+const char* GetSnapInstanceName();
+bool IsRunningUnderSnap();
+bool IsRunningUnderFlatpak();
+bool IsPackagedAppFileExists();
+inline bool IsRunningUnderFlatpakOrSnap() {
+  return IsRunningUnderFlatpak() || IsRunningUnderSnap();
+}
+
+enum class PortalKind {
+  FilePicker,
+  MimeHandler,
+  Settings,
+  Location,
+  OpenUri,
+};
+bool ShouldUsePortal(PortalKind);
+
+// Tries to get a descriptive identifier for the desktop environment that the
+// program is running under. Always normalized to lowercase.
+// See the implementation for the different environment variables and desktop
+// information we try to use.
+//
+// If we can't find a reasonable environment, the empty string is returned.
+const nsCString& GetDesktopEnvironmentIdentifier();
+bool IsGnomeDesktopEnvironment();
+bool IsKdeDesktopEnvironment();
+
+// Parse text/uri-list
+nsTArray<nsCString> ParseTextURIList(const nsACString& data);
+
+using FocusRequestPromise = MozPromise<nsCString, bool, false>;
+RefPtr<FocusRequestPromise> RequestWaylandFocusPromise();
+
+bool IsCancelledGError(GError* aGError);
+
+}  // namespace mozilla::widget
+
+#endif  // WidgetUtilsGtk_h__
diff --git a/widget/gtk/WindowSurface.h b/widget/gtk/WindowSurface.h
new file mode 100644
index 0000000000..858ddde59e
--- /dev/null
+++ b/widget/gtk/WindowSurface.h
@@ -0,0 +1,41 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _MOZILLA_WIDGET_WINDOW_SURFACE_H
+#define _MOZILLA_WIDGET_WINDOW_SURFACE_H
+
+#include "mozilla/gfx/2D.h"
+#include "Units.h"
+
+namespace mozilla {
+namespace widget {
+
+// A class for drawing to double-buffered windows.
+class WindowSurface {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WindowSurface);
+
+  // Locks a region of the window for drawing, returning a draw target
+  // capturing the bounds of the provided region.
+  // Implementations must permit invocation from any thread.
+  virtual already_AddRefed<gfx::DrawTarget> Lock(
+      const LayoutDeviceIntRegion& aRegion) = 0;
+
+  // Swaps the provided invalid region from the back buffer to the window.
+  // Implementations must permit invocation from any thread.
+  virtual void Commit(const LayoutDeviceIntRegion& aInvalidRegion) = 0;
+
+  // Whether the window surface represents a fallback method.
+  virtual bool IsFallback() const { return false; }
+
+ protected:
+  virtual ~WindowSurface() = default;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // _MOZILLA_WIDGET_WINDOW_SURFACE_H
diff --git a/widget/gtk/WindowSurfaceProvider.cpp b/widget/gtk/WindowSurfaceProvider.cpp
new file mode 100644
index 0000000000..b346f0783d
--- /dev/null
+++ b/widget/gtk/WindowSurfaceProvider.cpp
@@ -0,0 +1,212 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WindowSurfaceProvider.h"
+
+#include "gfxPlatformGtk.h"
+#include "GtkCompositorWidget.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "nsWindow.h"
+
+#ifdef MOZ_WAYLAND
+#  include "mozilla/StaticPrefs_widget.h"
+#  include "WindowSurfaceWaylandMultiBuffer.h"
+#endif
+#ifdef MOZ_X11
+#  include "mozilla/X11Util.h"
+#  include "WindowSurfaceX11Image.h"
+#  include "WindowSurfaceX11SHM.h"
+#endif
+
+#undef LOG
+#ifdef MOZ_LOGGING
+#  include "mozilla/Logging.h"
+#  include "nsTArray.h"
+#  include "Units.h"
+extern mozilla::LazyLogModule gWidgetLog;
+#  define LOG(args) MOZ_LOG(gWidgetLog, mozilla::LogLevel::Debug, args)
+#else
+#  define LOG(args)
+#endif /* MOZ_LOGGING */
+
+namespace mozilla {
+namespace widget {
+
+using namespace mozilla::layers;
+
+WindowSurfaceProvider::WindowSurfaceProvider()
+    : mWindowSurface(nullptr),
+      mMutex("WindowSurfaceProvider"),
+      mWindowSurfaceValid(false)
+#ifdef MOZ_X11
+      ,
+      mIsShaped(false),
+      mXDepth(0),
+      mXWindow(0),
+      mXVisual(nullptr)
+#endif
+{
+}
+
+WindowSurfaceProvider::~WindowSurfaceProvider() {
+#ifdef MOZ_WAYLAND
+  MOZ_DIAGNOSTIC_ASSERT(!mWidget,
+                        "nsWindow reference is still live, we're leaking it!");
+#endif
+#ifdef MOZ_X11
+  MOZ_DIAGNOSTIC_ASSERT(!mXWindow, "mXWindow should be released on quit!");
+#endif
+}
+
+#ifdef MOZ_WAYLAND
+void WindowSurfaceProvider::Initialize(RefPtr<nsWindow> aWidget) {
+  mWindowSurfaceValid = false;
+  mWidget = std::move(aWidget);
+}
+void WindowSurfaceProvider::Initialize(GtkCompositorWidget* aCompositorWidget) {
+  mWindowSurfaceValid = false;
+  mCompositorWidget = aCompositorWidget;
+  mWidget = static_cast<nsWindow*>(aCompositorWidget->RealWidget());
+}
+#endif
+#ifdef MOZ_X11
+void WindowSurfaceProvider::Initialize(Window aWindow, Visual* aVisual,
+                                       int aDepth, bool aIsShaped) {
+  mWindowSurfaceValid = false;
+  mXWindow = aWindow;
+  mXVisual = aVisual;
+  mXDepth = aDepth;
+  mIsShaped = aIsShaped;
+}
+#endif
+
+void WindowSurfaceProvider::CleanupResources() {
+  MutexAutoLock lock(mMutex);
+  mWindowSurfaceValid = false;
+#ifdef MOZ_WAYLAND
+  mWidget = nullptr;
+#endif
+#ifdef MOZ_X11
+  mXWindow = 0;
+  mXVisual = 0;
+  mXDepth = 0;
+  mIsShaped = false;
+#endif
+}
+
+RefPtr<WindowSurface> WindowSurfaceProvider::CreateWindowSurface() {
+#ifdef MOZ_WAYLAND
+  if (GdkIsWaylandDisplay()) {
+    // We're called too early or we're unmapped.
+    if (!mWidget) {
+      return nullptr;
+    }
+    return MakeRefPtr<WindowSurfaceWaylandMB>(mWidget, mCompositorWidget);
+  }
+#endif
+#ifdef MOZ_X11
+  if (GdkIsX11Display()) {
+    // We're called too early or we're unmapped.
+    if (!mXWindow) {
+      return nullptr;
+    }
+    // Blit to the window with the following priority:
+    // 1. MIT-SHM
+    // 2. XPutImage
+#  ifdef MOZ_HAVE_SHMIMAGE
+    if (!mIsShaped && nsShmImage::UseShm()) {
+      LOG(("Drawing to Window 0x%lx will use MIT-SHM\n", mXWindow));
+      return MakeRefPtr<WindowSurfaceX11SHM>(DefaultXDisplay(), mXWindow,
+                                             mXVisual, mXDepth);
+    }
+#  endif  // MOZ_HAVE_SHMIMAGE
+
+    LOG(("Drawing to Window 0x%lx will use XPutImage\n", mXWindow));
+    return MakeRefPtr<WindowSurfaceX11Image>(DefaultXDisplay(), mXWindow,
+                                             mXVisual, mXDepth, mIsShaped);
+  }
+#endif
+  MOZ_RELEASE_ASSERT(false);
+}
+
+already_AddRefed<gfx::DrawTarget>
+WindowSurfaceProvider::StartRemoteDrawingInRegion(
+    const LayoutDeviceIntRegion& aInvalidRegion,
+    layers::BufferMode* aBufferMode) {
+  if (aInvalidRegion.IsEmpty()) {
+    return nullptr;
+  }
+
+  MutexAutoLock lock(mMutex);
+
+  if (!mWindowSurfaceValid) {
+    mWindowSurface = nullptr;
+    mWindowSurfaceValid = true;
+  }
+
+  if (!mWindowSurface) {
+    mWindowSurface = CreateWindowSurface();
+    if (!mWindowSurface) {
+      return nullptr;
+    }
+  }
+
+  *aBufferMode = BufferMode::BUFFER_NONE;
+  RefPtr<gfx::DrawTarget> dt = mWindowSurface->Lock(aInvalidRegion);
+#ifdef MOZ_X11
+  if (!dt && GdkIsX11Display() && !mWindowSurface->IsFallback()) {
+    // We can't use WindowSurfaceX11Image fallback on Wayland but
+    // Lock() call on WindowSurfaceWayland should never fail.
+    gfxWarningOnce()
+        << "Failed to lock WindowSurface, falling back to XPutImage backend.";
+    mWindowSurface = MakeRefPtr<WindowSurfaceX11Image>(
+        DefaultXDisplay(), mXWindow, mXVisual, mXDepth, mIsShaped);
+    dt = mWindowSurface->Lock(aInvalidRegion);
+  }
+#endif
+  return dt.forget();
+}
+
+void WindowSurfaceProvider::EndRemoteDrawingInRegion(
+    gfx::DrawTarget* aDrawTarget, const LayoutDeviceIntRegion& aInvalidRegion) {
+  MutexAutoLock lock(mMutex);
+  // Commit to mWindowSurface only if we have a valid one.
+  if (!mWindowSurface || !mWindowSurfaceValid) {
+    return;
+  }
+#if defined(MOZ_WAYLAND)
+  if (GdkIsWaylandDisplay()) {
+    // We're called too early or we're unmapped.
+    // Don't draw anything.
+    if (!mWidget || !mWidget->IsMapped()) {
+      return;
+    }
+    if (moz_container_wayland_is_commiting_to_parent(
+            mWidget->GetMozContainer())) {
+      // If we're drawing directly to wl_surface owned by Gtk we need to use it
+      // in main thread to sync with Gtk access to it.
+      NS_DispatchToMainThread(NS_NewRunnableFunction(
+          "WindowSurfaceProvider::EndRemoteDrawingInRegion",
+          [widget = RefPtr{mWidget}, this, aInvalidRegion]() {
+            if (!widget->IsMapped()) {
+              return;
+            }
+            MutexAutoLock lock(mMutex);
+            // Commit to mWindowSurface only when we have a valid one.
+            if (mWindowSurface && mWindowSurfaceValid) {
+              mWindowSurface->Commit(aInvalidRegion);
+            }
+          }));
+      return;
+    }
+  }
+#endif
+  mWindowSurface->Commit(aInvalidRegion);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/gtk/WindowSurfaceProvider.h b/widget/gtk/WindowSurfaceProvider.h
new file mode 100644
index 0000000000..a040bbe395
--- /dev/null
+++ b/widget/gtk/WindowSurfaceProvider.h
@@ -0,0 +1,101 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_PROVIDER_H
+#define _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_PROVIDER_H
+
+#include <gdk/gdk.h>
+
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Types.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/widget/WindowSurface.h"
+#include "Units.h"
+#include "mozilla/ScopeExit.h"
+
+#ifdef MOZ_X11
+#  include <X11/Xlib.h>  // for Window, Display, Visual, etc.
+#  include "X11UndefineNone.h"
+#endif
+
+class nsWindow;
+
+namespace mozilla {
+namespace widget {
+
+class GtkCompositorWidget;
+
+/*
+ * Holds the logic for creating WindowSurface's for a GTK nsWindow.
+ * The main purpose of this class is to allow sharing of logic between
+ * nsWindow and GtkCompositorWidget, for when OMTC is enabled or disabled.
+ */
+class WindowSurfaceProvider final {
+ public:
+  WindowSurfaceProvider();
+  ~WindowSurfaceProvider();
+
+  /**
+   * Initializes the WindowSurfaceProvider by giving it the window
+   * handle and display to attach to. WindowSurfaceProvider doesn't
+   * own the Display, Window, etc, and they must continue to exist
+   * while WindowSurfaceProvider is used.
+   */
+#ifdef MOZ_WAYLAND
+  void Initialize(RefPtr<nsWindow> aWidget);
+  void Initialize(GtkCompositorWidget* aCompositorWidget);
+#endif
+#ifdef MOZ_X11
+  void Initialize(Window aWindow, Visual* aVisual, int aDepth, bool aIsShaped);
+#endif
+
+  /**
+   * Releases any surfaces created by this provider.
+   * This is used by GtkCompositorWidget to get rid
+   * of resources.
+   */
+  void CleanupResources();
+
+  already_AddRefed<gfx::DrawTarget> StartRemoteDrawingInRegion(
+      const LayoutDeviceIntRegion& aInvalidRegion,
+      layers::BufferMode* aBufferMode);
+  void EndRemoteDrawingInRegion(gfx::DrawTarget* aDrawTarget,
+                                const LayoutDeviceIntRegion& aInvalidRegion);
+
+ private:
+  RefPtr<WindowSurface> CreateWindowSurface();
+  void CleanupWindowSurface();
+
+  RefPtr<WindowSurface> mWindowSurface;
+
+  /* While CleanupResources() can be called from Main thread when nsWindow is
+   * destroyed/hidden, StartRemoteDrawingInRegion()/EndRemoteDrawingInRegion()
+   * is called from Compositor thread during rendering.
+   *
+   * As nsWindow CleanupResources() call comes from Gtk/X11 we can't synchronize
+   * that with WebRender so we use lock to synchronize the access.
+   */
+  mozilla::Mutex mMutex MOZ_UNANNOTATED;
+  // WindowSurface needs to be re-created as underlying window was changed.
+  mozilla::Atomic<bool> mWindowSurfaceValid;
+#ifdef MOZ_WAYLAND
+  RefPtr<nsWindow> mWidget;
+  // WindowSurfaceProvider is owned by GtkCompositorWidget so we don't need
+  // to reference it.
+  GtkCompositorWidget* mCompositorWidget = nullptr;
+#endif
+#ifdef MOZ_X11
+  bool mIsShaped;
+  int mXDepth;
+  Window mXWindow;
+  Visual* mXVisual;
+#endif
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_PROVIDER_H
diff --git a/widget/gtk/WindowSurfaceWaylandMultiBuffer.cpp b/widget/gtk/WindowSurfaceWaylandMultiBuffer.cpp
new file mode 100644
index 0000000000..96f478b726
--- /dev/null
+++ b/widget/gtk/WindowSurfaceWaylandMultiBuffer.cpp
@@ -0,0 +1,418 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WindowSurfaceWaylandMultiBuffer.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <prenv.h>
+
+#include "gfx2DGlue.h"
+#include "gfxPlatform.h"
+#include "MozContainer.h"
+#include "GtkCompositorWidget.h"
+#include "mozilla/gfx/DataSurfaceHelpers.h"
+#include "mozilla/gfx/Tools.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/WidgetUtils.h"
+
+#undef LOG
+#ifdef MOZ_LOGGING
+#  include "mozilla/Logging.h"
+#  include "Units.h"
+extern mozilla::LazyLogModule gWidgetWaylandLog;
+#  define LOGWAYLAND(...) \
+    MOZ_LOG(gWidgetWaylandLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#else
+#  define LOGWAYLAND(...)
+#endif /* MOZ_LOGGING */
+
+namespace mozilla::widget {
+
+/*
+  Wayland multi-thread rendering scheme
+
+  Every rendering thread (main thread, compositor thread) contains its own
+  nsWaylandDisplay object connected to Wayland compositor (Mutter, Weston, etc.)
+
+  WindowSurfaceWayland implements WindowSurface class and draws nsWindow by
+  WindowSurface interface (Lock, Commit) to screen through nsWaylandDisplay.
+
+  ----------------------
+  | Wayland compositor |
+  ----------------------
+             ^
+             |
+  ----------------------
+  |  nsWaylandDisplay  |
+  ----------------------
+        ^          ^
+        |          |
+        |          |
+        |       ---------------------------------        ------------------
+        |       | WindowSurfaceWayland          |<------>| nsWindow       |
+        |       |                               |        ------------------
+        |       |  -----------------------      |
+        |       |  | WaylandBufferSHM    |      |
+        |       |  |                     |      |
+        |       |  | ------------------- |      |
+        |       |  | |  WaylandShmPool | |      |
+        |       |  | ------------------- |      |
+        |       |  -----------------------      |
+        |       |                               |
+        |       |  -----------------------      |
+        |       |  | WaylandBufferSHM    |      |
+        |       |  |                     |      |
+        |       |  | ------------------- |      |
+        |       |  | |  WaylandShmPool | |      |
+        |       |  | ------------------- |      |
+        |       |  -----------------------      |
+        |       ---------------------------------
+        |
+        |
+  ---------------------------------        ------------------
+  | WindowSurfaceWayland          |<------>| nsWindow       |
+  |                               |        ------------------
+  |  -----------------------      |
+  |  | WaylandBufferSHM    |      |
+  |  |                     |      |
+  |  | ------------------- |      |
+  |  | |  WaylandShmPool | |      |
+  |  | ------------------- |      |
+  |  -----------------------      |
+  |                               |
+  |  -----------------------      |
+  |  | WaylandBufferSHM    |      |
+  |  |                     |      |
+  |  | ------------------- |      |
+  |  | |  WaylandShmPool | |      |
+  |  | ------------------- |      |
+  |  -----------------------      |
+  ---------------------------------
+
+
+nsWaylandDisplay
+
+Is our connection to Wayland display server,
+holds our display connection (wl_display) and event queue (wl_event_queue).
+
+nsWaylandDisplay is created for every thread which sends data to Wayland
+compositor. Wayland events for main thread is served by default Gtk+ loop,
+for other threads (compositor) we must create wl_event_queue and run event loop.
+
+
+WindowSurfaceWayland
+
+Is a Wayland implementation of WindowSurface class for WindowSurfaceProvider,
+we implement Lock() and Commit() interfaces from WindowSurface
+for actual drawing.
+
+One WindowSurfaceWayland draws one nsWindow so those are tied 1:1.
+At Wayland level it holds one wl_surface object.
+
+To perform visualiation of nsWindow, WindowSurfaceWayland contains one
+wl_surface and two wl_buffer objects (owned by WaylandBufferSHM)
+as we use double buffering. When nsWindow drawing is finished to wl_buffer,
+the wl_buffer is attached to wl_surface and it's sent to Wayland compositor.
+
+When there's no wl_buffer available for drawing (all wl_buffers are locked in
+compositor for instance) we store the drawing to WindowImageSurface object
+and draw later when wl_buffer becomes available or discard the
+WindowImageSurface cache when whole screen is invalidated.
+
+WaylandBufferSHM
+
+Is a class which provides a wl_buffer for drawing.
+Wl_buffer is a main Wayland object with actual graphics data.
+Wl_buffer basically represent one complete window screen.
+When double buffering is involved every window (GdkWindow for instance)
+utilises two wl_buffers which are cycled. One is filed with data by application
+and one is rendered by compositor.
+
+WaylandBufferSHM is implemented by shared memory (shm).
+It owns wl_buffer object, owns WaylandShmPool
+(which provides the shared memory) and ties them together.
+
+WaylandShmPool
+
+WaylandShmPool acts as a manager of shared memory for WaylandBufferSHM.
+Allocates it, holds reference to it and releases it.
+
+We allocate shared memory (shm) by mmap(..., MAP_SHARED,...) as an interface
+between us and wayland compositor. We draw our graphics data to the shm and
+handle to wayland compositor by WaylandBufferSHM/WindowSurfaceWayland
+(wl_buffer/wl_surface).
+*/
+
+using gfx::DataSourceSurface;
+
+#define BACK_BUFFER_NUM 3
+
+WindowSurfaceWaylandMB::WindowSurfaceWaylandMB(
+    RefPtr<nsWindow> aWindow, GtkCompositorWidget* aCompositorWidget)
+    : mSurfaceLock("WindowSurfaceWayland lock"),
+      mWindow(std::move(aWindow)),
+      mCompositorWidget(aCompositorWidget),
+      mFrameInProcess(false),
+      mCallbackRequested(false) {}
+
+bool WindowSurfaceWaylandMB::MaybeUpdateWindowSize() {
+  // We want to get window size from compositor widget as it matches window
+  // size used by parent RenderCompositorSWGL rendrer.
+  // For main thread rendering mCompositorWidget is not available so get
+  // window size directly from nsWindow.
+  LayoutDeviceIntSize newWindowSize = mCompositorWidget
+                                          ? mCompositorWidget->GetClientSize()
+                                          : mWindow->GetClientSize();
+  if (mWindowSize != newWindowSize) {
+    mWindowSize = newWindowSize;
+    return true;
+  }
+  return false;
+}
+
+already_AddRefed<DrawTarget> WindowSurfaceWaylandMB::Lock(
+    const LayoutDeviceIntRegion& aInvalidRegion) {
+  MutexAutoLock lock(mSurfaceLock);
+
+#ifdef MOZ_LOGGING
+  gfx::IntRect lockRect = aInvalidRegion.GetBounds().ToUnknownRect();
+  LOGWAYLAND("WindowSurfaceWaylandMB::Lock [%p] [%d,%d] -> [%d x %d] rects %d",
+             (void*)mWindow.get(), lockRect.x, lockRect.y, lockRect.width,
+             lockRect.height, aInvalidRegion.GetNumRects());
+#endif
+
+  if (mWindow->GetWindowType() == WindowType::Invisible) {
+    return nullptr;
+  }
+  mFrameInProcess = true;
+
+  CollectPendingSurfaces(lock);
+
+  if (MaybeUpdateWindowSize()) {
+    LOGWAYLAND("  new window size [%d x %d]", mWindowSize.width,
+               mWindowSize.height);
+    if (mInProgressBuffer) {
+      ReturnBufferToPool(lock, mInProgressBuffer);
+      mInProgressBuffer = nullptr;
+    }
+    if (mFrontBuffer) {
+      ReturnBufferToPool(lock, mFrontBuffer);
+      mFrontBuffer = nullptr;
+    }
+    mAvailableBuffers.Clear();
+  }
+
+  if (!mInProgressBuffer) {
+    if (mFrontBuffer && !mFrontBuffer->IsAttached()) {
+      mInProgressBuffer = mFrontBuffer;
+    } else {
+      mInProgressBuffer = ObtainBufferFromPool(lock, mWindowSize);
+      if (!mInProgressBuffer) {
+        return nullptr;
+      }
+      if (mFrontBuffer) {
+        HandlePartialUpdate(lock, aInvalidRegion);
+        ReturnBufferToPool(lock, mFrontBuffer);
+      }
+    }
+    mFrontBuffer = nullptr;
+    mFrontBufferInvalidRegion.SetEmpty();
+  }
+
+  RefPtr<DrawTarget> dt = mInProgressBuffer->Lock();
+  return dt.forget();
+}
+
+void WindowSurfaceWaylandMB::HandlePartialUpdate(
+    const MutexAutoLock& aProofOfLock,
+    const LayoutDeviceIntRegion& aInvalidRegion) {
+  LayoutDeviceIntRegion copyRegion;
+  if (mInProgressBuffer->GetBufferAge() == 2) {
+    copyRegion.Sub(mFrontBufferInvalidRegion, aInvalidRegion);
+  } else {
+    LayoutDeviceIntSize frontBufferSize = mFrontBuffer->GetSize();
+    copyRegion = LayoutDeviceIntRegion(LayoutDeviceIntRect(
+        0, 0, frontBufferSize.width, frontBufferSize.height));
+    copyRegion.SubOut(aInvalidRegion);
+  }
+
+  if (!copyRegion.IsEmpty()) {
+    RefPtr<DataSourceSurface> dataSourceSurface =
+        mozilla::gfx::CreateDataSourceSurfaceFromData(
+            mFrontBuffer->GetSize().ToUnknownSize(),
+            mFrontBuffer->GetSurfaceFormat(),
+            (const uint8_t*)mFrontBuffer->GetShmPool()->GetImageData(),
+            mFrontBuffer->GetSize().width *
+                BytesPerPixel(mFrontBuffer->GetSurfaceFormat()));
+    RefPtr<DrawTarget> dt = mInProgressBuffer->Lock();
+
+    for (auto iter = copyRegion.RectIter(); !iter.Done(); iter.Next()) {
+      LayoutDeviceIntRect r = iter.Get();
+      dt->CopySurface(dataSourceSurface, r.ToUnknownRect(),
+                      gfx::IntPoint(r.x, r.y));
+    }
+  }
+}
+
+void WindowSurfaceWaylandMB::Commit(
+    const LayoutDeviceIntRegion& aInvalidRegion) {
+  MutexAutoLock lock(mSurfaceLock);
+  Commit(lock, aInvalidRegion);
+}
+
+void WindowSurfaceWaylandMB::Commit(
+    const MutexAutoLock& aProofOfLock,
+    const LayoutDeviceIntRegion& aInvalidRegion) {
+#ifdef MOZ_LOGGING
+  gfx::IntRect invalidRect = aInvalidRegion.GetBounds().ToUnknownRect();
+  LOGWAYLAND(
+      "WindowSurfaceWaylandMB::Commit [%p] damage rect [%d, %d] -> [%d x %d] "
+      "Window [%d x %d]\n",
+      (void*)mWindow.get(), invalidRect.x, invalidRect.y, invalidRect.width,
+      invalidRect.height, mWindowSize.width, mWindowSize.height);
+#endif
+
+  if (!mInProgressBuffer) {
+    // invisible window
+    return;
+  }
+  mFrameInProcess = false;
+
+  MozContainer* container = mWindow->GetMozContainer();
+  MozContainerSurfaceLock MozContainerLock(container);
+  struct wl_surface* waylandSurface = MozContainerLock.GetSurface();
+  if (!waylandSurface) {
+    LOGWAYLAND(
+        "WindowSurfaceWaylandMB::Commit [%p] frame queued: can't lock "
+        "wl_surface\n",
+        (void*)mWindow.get());
+    if (!mCallbackRequested) {
+      RefPtr<WindowSurfaceWaylandMB> self(this);
+      moz_container_wayland_add_initial_draw_callback_locked(
+          container, [self, aInvalidRegion]() -> void {
+            MutexAutoLock lock(self->mSurfaceLock);
+            if (!self->mFrameInProcess) {
+              self->Commit(lock, aInvalidRegion);
+            }
+            self->mCallbackRequested = false;
+          });
+      mCallbackRequested = true;
+    }
+    return;
+  }
+
+  if (moz_container_wayland_is_commiting_to_parent(container)) {
+    // When committing to parent surface we must use wl_surface_damage().
+    // A parent surface is created as v.3 object which does not support
+    // wl_surface_damage_buffer().
+    wl_surface_damage(waylandSurface, 0, 0, INT32_MAX, INT32_MAX);
+  } else {
+    for (auto iter = aInvalidRegion.RectIter(); !iter.Done(); iter.Next()) {
+      LayoutDeviceIntRect r = iter.Get();
+      wl_surface_damage_buffer(waylandSurface, r.x, r.y, r.width, r.height);
+    }
+  }
+
+  // aProofOfLock is a kind of substitution of MozContainerSurfaceLock.
+  // MozContainer is locked but MozContainerSurfaceLock doen't convert to
+  // MutexAutoLock& so we use aProofOfLock here.
+  moz_container_wayland_set_scale_factor_locked(
+      aProofOfLock, container, mWindow->GdkCeiledScaleFactor());
+
+  // It's possible that scale factor changed between Lock() and Commit()
+  // but window size is the same.
+  // Don't attach such buffer as it may have incorrect size,
+  // we'll paint new content soon.
+  if (moz_container_wayland_size_matches_scale_factor_locked(
+          aProofOfLock, container, mWindowSize.width, mWindowSize.height)) {
+    mInProgressBuffer->AttachAndCommit(waylandSurface);
+  }
+
+  mInProgressBuffer->ResetBufferAge();
+  mFrontBuffer = mInProgressBuffer;
+  mFrontBufferInvalidRegion = aInvalidRegion;
+  mInProgressBuffer = nullptr;
+
+  EnforcePoolSizeLimit(aProofOfLock);
+  IncrementBufferAge(aProofOfLock);
+
+  if (wl_display_flush(WaylandDisplayGet()->GetDisplay()) == -1) {
+    LOGWAYLAND("WindowSurfaceWaylandMB::Commit [%p] flush failed\n",
+               (void*)mWindow.get());
+  }
+}
+
+RefPtr<WaylandBufferSHM> WindowSurfaceWaylandMB::ObtainBufferFromPool(
+    const MutexAutoLock& aProofOfLock, const LayoutDeviceIntSize& aSize) {
+  if (!mAvailableBuffers.IsEmpty()) {
+    RefPtr<WaylandBufferSHM> buffer = mAvailableBuffers.PopLastElement();
+    mInUseBuffers.AppendElement(buffer);
+    return buffer;
+  }
+
+  RefPtr<WaylandBufferSHM> buffer = WaylandBufferSHM::Create(aSize);
+  if (buffer) {
+    mInUseBuffers.AppendElement(buffer);
+  }
+
+  return buffer;
+}
+
+void WindowSurfaceWaylandMB::ReturnBufferToPool(
+    const MutexAutoLock& aProofOfLock,
+    const RefPtr<WaylandBufferSHM>& aBuffer) {
+  if (aBuffer->IsAttached()) {
+    mPendingBuffers.AppendElement(aBuffer);
+  } else if (aBuffer->IsMatchingSize(mWindowSize)) {
+    mAvailableBuffers.AppendElement(aBuffer);
+  }
+  mInUseBuffers.RemoveElement(aBuffer);
+}
+
+void WindowSurfaceWaylandMB::EnforcePoolSizeLimit(
+    const MutexAutoLock& aProofOfLock) {
+  // Enforce the pool size limit, removing least-recently-used entries as
+  // necessary.
+  while (mAvailableBuffers.Length() > BACK_BUFFER_NUM) {
+    mAvailableBuffers.RemoveElementAt(0);
+  }
+
+  NS_WARNING_ASSERTION(mPendingBuffers.Length() < BACK_BUFFER_NUM,
+                       "Are we leaking pending buffers?");
+  NS_WARNING_ASSERTION(mInUseBuffers.Length() < BACK_BUFFER_NUM,
+                       "Are we leaking in-use buffers?");
+}
+
+void WindowSurfaceWaylandMB::CollectPendingSurfaces(
+    const MutexAutoLock& aProofOfLock) {
+  mPendingBuffers.RemoveElementsBy([&](auto& buffer) {
+    if (!buffer->IsAttached()) {
+      if (buffer->IsMatchingSize(mWindowSize)) {
+        mAvailableBuffers.AppendElement(std::move(buffer));
+      }
+      return true;
+    }
+    return false;
+  });
+}
+
+void WindowSurfaceWaylandMB::IncrementBufferAge(
+    const MutexAutoLock& aProofOfLock) {
+  for (const RefPtr<WaylandBufferSHM>& buffer : mInUseBuffers) {
+    buffer->IncrementBufferAge();
+  }
+  for (const RefPtr<WaylandBufferSHM>& buffer : mPendingBuffers) {
+    buffer->IncrementBufferAge();
+  }
+  for (const RefPtr<WaylandBufferSHM>& buffer : mAvailableBuffers) {
+    buffer->IncrementBufferAge();
+  }
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/WindowSurfaceWaylandMultiBuffer.h b/widget/gtk/WindowSurfaceWaylandMultiBuffer.h
new file mode 100644
index 0000000000..e14a626de0
--- /dev/null
+++ b/widget/gtk/WindowSurfaceWaylandMultiBuffer.h
@@ -0,0 +1,84 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_WAYLAND_MULTI_BUFFER_H
+#define _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_WAYLAND_MULTI_BUFFER_H
+
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Types.h"
+#include "mozilla/Mutex.h"
+#include "nsTArray.h"
+#include "nsWaylandDisplay.h"
+#include "nsWindow.h"
+#include "WaylandBuffer.h"
+#include "WindowSurface.h"
+
+namespace mozilla::widget {
+
+using gfx::DrawTarget;
+
+// WindowSurfaceWaylandMB is an abstraction for wl_surface
+// and related management
+class WindowSurfaceWaylandMB : public WindowSurface {
+ public:
+  WindowSurfaceWaylandMB(RefPtr<nsWindow> aWindow,
+                         GtkCompositorWidget* aCompositorWidget);
+  ~WindowSurfaceWaylandMB() = default;
+
+  // Lock() / Commit() are called by gecko when Firefox
+  // wants to display something. Lock() returns a DrawTarget
+  // where gecko paints. When gecko is done it calls Commit()
+  // and we try to send the DrawTarget (backed by wl_buffer)
+  // to wayland compositor.
+  //
+  // If we fail (wayland compositor is busy,
+  // wl_surface is not created yet) we queue the painting
+  // and we send it to wayland compositor in FrameCallbackHandler()/
+  // FlushPendingCommits().
+  already_AddRefed<DrawTarget> Lock(
+      const LayoutDeviceIntRegion& aInvalidRegion) override;
+  void Commit(const LayoutDeviceIntRegion& aInvalidRegion) final;
+
+ private:
+  void Commit(const MutexAutoLock& aProofOfLock,
+              const LayoutDeviceIntRegion& aInvalidRegion);
+  RefPtr<WaylandBufferSHM> ObtainBufferFromPool(
+      const MutexAutoLock& aProofOfLock, const LayoutDeviceIntSize& aSize);
+  void ReturnBufferToPool(const MutexAutoLock& aProofOfLock,
+                          const RefPtr<WaylandBufferSHM>& aBuffer);
+  void EnforcePoolSizeLimit(const MutexAutoLock& aProofOfLock);
+  void CollectPendingSurfaces(const MutexAutoLock& aProofOfLock);
+  void HandlePartialUpdate(const MutexAutoLock& aProofOfLock,
+                           const LayoutDeviceIntRegion& aInvalidRegion);
+  void IncrementBufferAge(const MutexAutoLock& aProofOfLock);
+  // Return true if window size was updated.
+  bool MaybeUpdateWindowSize();
+
+  mozilla::Mutex mSurfaceLock MOZ_UNANNOTATED;
+
+  RefPtr<nsWindow> mWindow;
+  // WindowSurfaceWaylandMB is owned by GtkCompositorWidget so we can't
+  // reference it.
+  GtkCompositorWidget* mCompositorWidget;
+  LayoutDeviceIntSize mWindowSize;
+
+  RefPtr<WaylandBufferSHM> mInProgressBuffer;
+  RefPtr<WaylandBufferSHM> mFrontBuffer;
+  LayoutDeviceIntRegion mFrontBufferInvalidRegion;
+
+  // buffer pool
+  nsTArray<RefPtr<WaylandBufferSHM>> mInUseBuffers;
+  nsTArray<RefPtr<WaylandBufferSHM>> mPendingBuffers;
+  nsTArray<RefPtr<WaylandBufferSHM>> mAvailableBuffers;
+
+  // delayed commits
+  bool mFrameInProcess;
+  bool mCallbackRequested;
+};
+
+}  // namespace mozilla::widget
+
+#endif  // _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_WAYLAND_MULTI_BUFFER_H
diff --git a/widget/gtk/WindowSurfaceX11.cpp b/widget/gtk/WindowSurfaceX11.cpp
new file mode 100644
index 0000000000..36b238a98b
--- /dev/null
+++ b/widget/gtk/WindowSurfaceX11.cpp
@@ -0,0 +1,47 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WindowSurfaceX11.h"
+#include "gfxPlatform.h"
+
+namespace mozilla::widget {
+
+WindowSurfaceX11::WindowSurfaceX11(Display* aDisplay, Window aWindow,
+                                   Visual* aVisual, unsigned int aDepth)
+    : mDisplay(aDisplay),
+      mWindow(aWindow),
+      mVisual(aVisual),
+      mDepth(aDepth),
+      mFormat(GetVisualFormat(aVisual, aDepth)) {}
+
+/* static */
+gfx::SurfaceFormat WindowSurfaceX11::GetVisualFormat(const Visual* aVisual,
+                                                     unsigned int aDepth) {
+  switch (aDepth) {
+    case 32:
+      if (aVisual->red_mask == 0xff0000 && aVisual->green_mask == 0xff00 &&
+          aVisual->blue_mask == 0xff) {
+        return gfx::SurfaceFormat::B8G8R8A8;
+      }
+      break;
+    case 24:
+      if (aVisual->red_mask == 0xff0000 && aVisual->green_mask == 0xff00 &&
+          aVisual->blue_mask == 0xff) {
+        return gfx::SurfaceFormat::B8G8R8X8;
+      }
+      break;
+    case 16:
+      if (aVisual->red_mask == 0xf800 && aVisual->green_mask == 0x07e0 &&
+          aVisual->blue_mask == 0x1f) {
+        return gfx::SurfaceFormat::R5G6B5_UINT16;
+      }
+      break;
+  }
+
+  return gfx::SurfaceFormat::UNKNOWN;
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/WindowSurfaceX11.h b/widget/gtk/WindowSurfaceX11.h
new file mode 100644
index 0000000000..dda17bf0d0
--- /dev/null
+++ b/widget/gtk/WindowSurfaceX11.h
@@ -0,0 +1,39 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_X11_H
+#define _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_X11_H
+
+#ifdef MOZ_X11
+
+#  include "mozilla/widget/WindowSurface.h"
+#  include "mozilla/gfx/Types.h"
+
+#  include <X11/Xlib.h>
+#  include "X11UndefineNone.h"
+
+namespace mozilla::widget {
+
+class WindowSurfaceX11 : public WindowSurface {
+ public:
+  WindowSurfaceX11(Display* aDisplay, Window aWindow, Visual* aVisual,
+                   unsigned int aDepth);
+
+ protected:
+  static gfx::SurfaceFormat GetVisualFormat(const Visual* aVisual,
+                                            unsigned int aDepth);
+
+  Display* const mDisplay;
+  const Window mWindow;
+  Visual* const mVisual;
+  const unsigned int mDepth;
+  const gfx::SurfaceFormat mFormat;
+};
+
+}  // namespace mozilla::widget
+
+#endif  // MOZ_X11
+#endif  // _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_X11_H
diff --git a/widget/gtk/WindowSurfaceX11Image.cpp b/widget/gtk/WindowSurfaceX11Image.cpp
new file mode 100644
index 0000000000..f797bfafad
--- /dev/null
+++ b/widget/gtk/WindowSurfaceX11Image.cpp
@@ -0,0 +1,272 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WindowSurfaceX11Image.h"
+
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Tools.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "gfxPlatform.h"
+#include "gfx2DGlue.h"
+
+#include <X11/extensions/shape.h>
+
+namespace mozilla {
+namespace widget {
+
+using namespace mozilla::gfx;
+
+// gfxImageSurface pixel format configuration.
+#define SHAPED_IMAGE_SURFACE_BPP 4
+#ifdef IS_BIG_ENDIAN
+#  define SHAPED_IMAGE_SURFACE_ALPHA_INDEX 0
+#else
+#  define SHAPED_IMAGE_SURFACE_ALPHA_INDEX 3
+#endif
+
+WindowSurfaceX11Image::WindowSurfaceX11Image(Display* aDisplay, Window aWindow,
+                                             Visual* aVisual,
+                                             unsigned int aDepth,
+                                             bool aIsShaped)
+    : WindowSurfaceX11(aDisplay, aWindow, aVisual, aDepth),
+      mTransparencyBitmap(nullptr),
+      mTransparencyBitmapWidth(0),
+      mTransparencyBitmapHeight(0),
+      mIsShaped(aIsShaped),
+      mWindowParent(0) {
+  if (!mIsShaped) {
+    return;
+  }
+
+  Window root, *children = nullptr;
+  unsigned int childrenNum;
+  if (XQueryTree(mDisplay, mWindow, &root, &mWindowParent, &children,
+                 &childrenNum)) {
+    if (children) {
+      XFree((char*)children);
+    }
+  }
+}
+
+WindowSurfaceX11Image::~WindowSurfaceX11Image() {
+  if (mTransparencyBitmap) {
+    delete[] mTransparencyBitmap;
+  }
+}
+
+already_AddRefed<gfx::DrawTarget> WindowSurfaceX11Image::Lock(
+    const LayoutDeviceIntRegion& aRegion) {
+  gfx::IntRect bounds = aRegion.GetBounds().ToUnknownRect();
+  gfx::IntSize size(bounds.XMost(), bounds.YMost());
+
+  if (!mWindowSurface || mWindowSurface->CairoStatus() ||
+      !(size <= mWindowSurface->GetSize())) {
+    mWindowSurface = new gfxXlibSurface(mDisplay, mWindow, mVisual, size);
+  }
+  if (mWindowSurface->CairoStatus()) {
+    return nullptr;
+  }
+
+  if (!mImageSurface || mImageSurface->CairoStatus() ||
+      !(size <= mImageSurface->GetSize())) {
+    gfxImageFormat format = SurfaceFormatToImageFormat(mFormat);
+    if (format == gfx::SurfaceFormat::UNKNOWN) {
+      format = mDepth == 32 ? gfx::SurfaceFormat::A8R8G8B8_UINT32
+                            : gfx::SurfaceFormat::X8R8G8B8_UINT32;
+    }
+
+    // Use alpha image format for shaped window as we derive
+    // the shape bitmap from alpha channel. Must match SHAPED_IMAGE_SURFACE_BPP
+    // and SHAPED_IMAGE_SURFACE_ALPHA_INDEX.
+    if (mIsShaped) {
+      format = gfx::SurfaceFormat::A8R8G8B8_UINT32;
+    }
+
+    mImageSurface = new gfxImageSurface(size, format);
+    if (mImageSurface->CairoStatus()) {
+      return nullptr;
+    }
+  }
+
+  gfxImageFormat format = mImageSurface->Format();
+  // Cairo prefers compositing to BGRX instead of BGRA where possible.
+  // Cairo/pixman lacks some fast paths for compositing BGRX onto BGRA, so
+  // just report it as BGRX directly in that case.
+  // Otherwise, for Skia, report it as BGRA to the compositor. The alpha
+  // channel will be discarded when we put the image.
+  if (format == gfx::SurfaceFormat::X8R8G8B8_UINT32) {
+    gfx::BackendType backend = gfxVars::ContentBackend();
+    if (!gfx::Factory::DoesBackendSupportDataDrawtarget(backend)) {
+      backend = gfx::BackendType::SKIA;
+    }
+    if (backend != gfx::BackendType::CAIRO) {
+      format = gfx::SurfaceFormat::A8R8G8B8_UINT32;
+    }
+  }
+
+  return gfxPlatform::CreateDrawTargetForData(
+      mImageSurface->Data(), mImageSurface->GetSize(), mImageSurface->Stride(),
+      ImageFormatToSurfaceFormat(format));
+}
+
+// The transparency bitmap routines are derived form the ones at nsWindow.cpp.
+// The difference here is that we compose to RGBA image and then create
+// the shape mask from final image alpha channel.
+static inline int32_t GetBitmapStride(int32_t width) { return (width + 7) / 8; }
+
+static bool ChangedMaskBits(gchar* aMaskBits, int32_t aMaskWidth,
+                            int32_t aMaskHeight, const nsIntRect& aRect,
+                            uint8_t* aImageData) {
+  int32_t stride = aMaskWidth * SHAPED_IMAGE_SURFACE_BPP;
+  int32_t x, y, xMax = aRect.XMost(), yMax = aRect.YMost();
+  int32_t maskBytesPerRow = GetBitmapStride(aMaskWidth);
+  for (y = aRect.y; y < yMax; y++) {
+    gchar* maskBytes = aMaskBits + y * maskBytesPerRow;
+    uint8_t* alphas = aImageData;
+    for (x = aRect.x; x < xMax; x++) {
+      bool newBit = *(alphas + SHAPED_IMAGE_SURFACE_ALPHA_INDEX) > 0x7f;
+      alphas += SHAPED_IMAGE_SURFACE_BPP;
+
+      gchar maskByte = maskBytes[x >> 3];
+      bool maskBit = (maskByte & (1 << (x & 7))) != 0;
+
+      if (maskBit != newBit) {
+        return true;
+      }
+    }
+    aImageData += stride;
+  }
+
+  return false;
+}
+
+static void UpdateMaskBits(gchar* aMaskBits, int32_t aMaskWidth,
+                           int32_t aMaskHeight, const nsIntRect& aRect,
+                           uint8_t* aImageData) {
+  int32_t stride = aMaskWidth * SHAPED_IMAGE_SURFACE_BPP;
+  int32_t x, y, xMax = aRect.XMost(), yMax = aRect.YMost();
+  int32_t maskBytesPerRow = GetBitmapStride(aMaskWidth);
+  for (y = aRect.y; y < yMax; y++) {
+    gchar* maskBytes = aMaskBits + y * maskBytesPerRow;
+    uint8_t* alphas = aImageData;
+    for (x = aRect.x; x < xMax; x++) {
+      bool newBit = *(alphas + SHAPED_IMAGE_SURFACE_ALPHA_INDEX) > 0x7f;
+      alphas += SHAPED_IMAGE_SURFACE_BPP;
+
+      gchar mask = 1 << (x & 7);
+      gchar maskByte = maskBytes[x >> 3];
+      // Note: '-newBit' turns 0 into 00...00 and 1 into 11...11
+      maskBytes[x >> 3] = (maskByte & ~mask) | (-newBit & mask);
+    }
+    aImageData += stride;
+  }
+}
+
+void WindowSurfaceX11Image::ResizeTransparencyBitmap(int aWidth, int aHeight) {
+  int32_t actualSize =
+      GetBitmapStride(mTransparencyBitmapWidth) * mTransparencyBitmapHeight;
+  int32_t newSize = GetBitmapStride(aWidth) * aHeight;
+
+  if (actualSize < newSize) {
+    delete[] mTransparencyBitmap;
+    mTransparencyBitmap = new gchar[newSize];
+  }
+
+  mTransparencyBitmapWidth = aWidth;
+  mTransparencyBitmapHeight = aHeight;
+}
+
+void WindowSurfaceX11Image::ApplyTransparencyBitmap() {
+  gfx::IntSize size = mWindowSurface->GetSize();
+  bool maskChanged = true;
+
+  if (!mTransparencyBitmap) {
+    mTransparencyBitmapWidth = size.width;
+    mTransparencyBitmapHeight = size.height;
+
+    int32_t byteSize =
+        GetBitmapStride(mTransparencyBitmapWidth) * mTransparencyBitmapHeight;
+    mTransparencyBitmap = new gchar[byteSize];
+  } else {
+    bool sizeChanged = (size.width != mTransparencyBitmapWidth ||
+                        size.height != mTransparencyBitmapHeight);
+
+    if (sizeChanged) {
+      ResizeTransparencyBitmap(size.width, size.height);
+    } else {
+      maskChanged = ChangedMaskBits(
+          mTransparencyBitmap, mTransparencyBitmapWidth,
+          mTransparencyBitmapHeight, nsIntRect(0, 0, size.width, size.height),
+          (uint8_t*)mImageSurface->Data());
+    }
+  }
+
+  if (maskChanged) {
+    UpdateMaskBits(mTransparencyBitmap, mTransparencyBitmapWidth,
+                   mTransparencyBitmapHeight,
+                   nsIntRect(0, 0, size.width, size.height),
+                   (uint8_t*)mImageSurface->Data());
+
+    // We use X11 calls where possible, because GDK handles expose events
+    // for shaped windows in a way that's incompatible with us (Bug 635903).
+    // It doesn't occur when the shapes are set through X.
+    Display* xDisplay = mWindowSurface->XDisplay();
+    Window xDrawable = mWindowSurface->XDrawable();
+    Pixmap maskPixmap = XCreateBitmapFromData(
+        xDisplay, xDrawable, mTransparencyBitmap, mTransparencyBitmapWidth,
+        mTransparencyBitmapHeight);
+    XShapeCombineMask(xDisplay, xDrawable, ShapeBounding, 0, 0, maskPixmap,
+                      ShapeSet);
+    if (mWindowParent) {
+      XShapeCombineMask(mDisplay, mWindowParent, ShapeBounding, 0, 0,
+                        maskPixmap, ShapeSet);
+    }
+    XFreePixmap(xDisplay, maskPixmap);
+  }
+}
+
+void WindowSurfaceX11Image::Commit(
+    const LayoutDeviceIntRegion& aInvalidRegion) {
+  RefPtr<gfx::DrawTarget> dt = gfx::Factory::CreateDrawTargetForCairoSurface(
+      mWindowSurface->CairoSurface(), mWindowSurface->GetSize());
+  RefPtr<gfx::SourceSurface> surf =
+      gfx::Factory::CreateSourceSurfaceForCairoSurface(
+          mImageSurface->CairoSurface(), mImageSurface->GetSize(),
+          mImageSurface->Format());
+  if (!dt || !surf) {
+    return;
+  }
+
+  gfx::IntRect bounds = aInvalidRegion.GetBounds().ToUnknownRect();
+  if (bounds.IsEmpty()) {
+    return;
+  }
+
+  if (mIsShaped) {
+    ApplyTransparencyBitmap();
+  }
+
+  uint32_t numRects = aInvalidRegion.GetNumRects();
+  if (numRects == 1) {
+    dt->CopySurface(surf, bounds, bounds.TopLeft());
+  } else {
+    AutoTArray<IntRect, 32> rects;
+    rects.SetCapacity(numRects);
+    for (auto iter = aInvalidRegion.RectIter(); !iter.Done(); iter.Next()) {
+      rects.AppendElement(iter.Get().ToUnknownRect());
+    }
+    dt->PushDeviceSpaceClipRects(rects.Elements(), rects.Length());
+
+    dt->DrawSurface(surf, gfx::Rect(bounds), gfx::Rect(bounds),
+                    DrawSurfaceOptions(),
+                    DrawOptions(1.0f, CompositionOp::OP_SOURCE));
+
+    dt->PopClip();
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/gtk/WindowSurfaceX11Image.h b/widget/gtk/WindowSurfaceX11Image.h
new file mode 100644
index 0000000000..281199b5dd
--- /dev/null
+++ b/widget/gtk/WindowSurfaceX11Image.h
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_X11_IMAGE_H
+#define _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_X11_IMAGE_H
+
+#ifdef MOZ_X11
+
+#  include <glib.h>
+#  include "WindowSurfaceX11.h"
+#  include "gfxXlibSurface.h"
+#  include "gfxImageSurface.h"
+
+namespace mozilla {
+namespace widget {
+
+class WindowSurfaceX11Image : public WindowSurfaceX11 {
+ public:
+  WindowSurfaceX11Image(Display* aDisplay, Window aWindow, Visual* aVisual,
+                        unsigned int aDepth, bool aIsShaped);
+  ~WindowSurfaceX11Image();
+
+  already_AddRefed<gfx::DrawTarget> Lock(
+      const LayoutDeviceIntRegion& aRegion) override;
+  void Commit(const LayoutDeviceIntRegion& aInvalidRegion) override;
+  bool IsFallback() const override { return true; }
+
+ private:
+  void ResizeTransparencyBitmap(int aWidth, int aHeight);
+  void ApplyTransparencyBitmap();
+
+  RefPtr<gfxXlibSurface> mWindowSurface;
+  RefPtr<gfxImageSurface> mImageSurface;
+
+  gchar* mTransparencyBitmap;
+  int32_t mTransparencyBitmapWidth;
+  int32_t mTransparencyBitmapHeight;
+  bool mIsShaped;
+  Window mWindowParent;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // MOZ_X11
+#endif  // _MOZILLA_WIDGET_GTK_WINDOW_SURFACE_X11_IMAGE_H
diff --git a/widget/gtk/WindowSurfaceX11SHM.cpp b/widget/gtk/WindowSurfaceX11SHM.cpp
new file mode 100644
index 0000000000..889881d22d
--- /dev/null
+++ b/widget/gtk/WindowSurfaceX11SHM.cpp
@@ -0,0 +1,27 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WindowSurfaceX11SHM.h"
+
+namespace mozilla::widget {
+
+WindowSurfaceX11SHM::WindowSurfaceX11SHM(Display* aDisplay, Drawable aWindow,
+                                         Visual* aVisual, unsigned int aDepth) {
+  mFrontImage = new nsShmImage(aDisplay, aWindow, aVisual, aDepth);
+  mBackImage = new nsShmImage(aDisplay, aWindow, aVisual, aDepth);
+}
+
+already_AddRefed<gfx::DrawTarget> WindowSurfaceX11SHM::Lock(
+    const LayoutDeviceIntRegion& aRegion) {
+  mBackImage.swap(mFrontImage);
+  return mBackImage->CreateDrawTarget(aRegion);
+}
+
+void WindowSurfaceX11SHM::Commit(const LayoutDeviceIntRegion& aInvalidRegion) {
+  mBackImage->Put(aInvalidRegion);
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/WindowSurfaceX11SHM.h b/widget/gtk/WindowSurfaceX11SHM.h
new file mode 100644
index 0000000000..5d12137f7b
--- /dev/null
+++ b/widget/gtk/WindowSurfaceX11SHM.h
@@ -0,0 +1,36 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _MOZILLA_WIDGET_WINDOW_SURFACE_X11_SHM_H
+#define _MOZILLA_WIDGET_WINDOW_SURFACE_X11_SHM_H
+
+#ifdef MOZ_X11
+
+#  include "mozilla/widget/WindowSurface.h"
+#  include "nsShmImage.h"
+
+namespace mozilla {
+namespace widget {
+
+class WindowSurfaceX11SHM : public WindowSurface {
+ public:
+  WindowSurfaceX11SHM(Display* aDisplay, Drawable aWindow, Visual* aVisual,
+                      unsigned int aDepth);
+
+  already_AddRefed<gfx::DrawTarget> Lock(
+      const LayoutDeviceIntRegion& aRegion) override;
+  void Commit(const LayoutDeviceIntRegion& aInvalidRegion) override;
+
+ private:
+  RefPtr<nsShmImage> mFrontImage;
+  RefPtr<nsShmImage> mBackImage;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // MOZ_X11
+#endif  // _MOZILLA_WIDGET_WINDOW_SURFACE_X11_SHM_H
diff --git a/widget/gtk/compat/gdk/gdkdnd.h b/widget/gtk/compat/gdk/gdkdnd.h
new file mode 100644
index 0000000000..bf9888d84f
--- /dev/null
+++ b/widget/gtk/compat/gdk/gdkdnd.h
@@ -0,0 +1,29 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GDKDND_WRAPPER_H
+#define GDKDND_WRAPPER_H
+
+#define gdk_drag_context_get_actions gdk_drag_context_get_actions_
+#define gdk_drag_context_list_targets gdk_drag_context_list_targets_
+#define gdk_drag_context_get_dest_window gdk_drag_context_get_dest_window_
+#include_next <gdk/gdkdnd.h>
+#undef gdk_drag_context_get_actions
+#undef gdk_drag_context_list_targets
+#undef gdk_drag_context_get_dest_window
+
+static inline GdkDragAction gdk_drag_context_get_actions(
+    GdkDragContext* context) {
+  return context->actions;
+}
+
+static inline GList* gdk_drag_context_list_targets(GdkDragContext* context) {
+  return context->targets;
+}
+
+static inline GdkWindow* gdk_drag_context_get_dest_window(
+    GdkDragContext* context) {
+  return context->dest_window;
+}
+#endif /* GDKDND_WRAPPER_H */
diff --git a/widget/gtk/compat/gdk/gdkkeysyms.h b/widget/gtk/compat/gdk/gdkkeysyms.h
new file mode 100644
index 0000000000..2f48d61fcc
--- /dev/null
+++ b/widget/gtk/compat/gdk/gdkkeysyms.h
@@ -0,0 +1,266 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GDKKEYSYMS_WRAPPER_H
+#define GDKKEYSYMS_WRAPPER_H
+
+#include_next <gdk/gdkkeysyms.h>
+
+#ifndef GDK_ISO_Level5_Shift
+#  define GDK_ISO_Level5_Shift 0xFE11
+#endif
+
+#ifndef GDK_ISO_Level5_Latch
+#  define GDK_ISO_Level5_Latch 0xFE12
+#endif
+
+#ifndef GDK_ISO_Level5_Lock
+#  define GDK_ISO_Level5_Lock 0xFE13
+#endif
+
+#ifndef GDK_dead_greek
+#  define GDK_dead_greek 0xFE8C
+#endif
+
+#ifndef GDK_ch
+#  define GDK_ch 0xFEA0
+#endif
+
+#ifndef GDK_Ch
+#  define GDK_Ch 0xFEA1
+#endif
+
+#ifndef GDK_CH
+#  define GDK_CH 0xFEA2
+#endif
+
+#ifndef GDK_c_h
+#  define GDK_c_h 0xFEA3
+#endif
+
+#ifndef GDK_C_h
+#  define GDK_C_h 0xFEA4
+#endif
+
+#ifndef GDK_C_H
+#  define GDK_C_H 0xFEA5
+#endif
+
+#ifndef GDK_MonBrightnessUp
+#  define GDK_MonBrightnessUp 0x1008FF02
+#endif
+
+#ifndef GDK_MonBrightnessDown
+#  define GDK_MonBrightnessDown 0x1008FF03
+#endif
+
+#ifndef GDK_AudioLowerVolume
+#  define GDK_AudioLowerVolume 0x1008FF11
+#endif
+
+#ifndef GDK_AudioMute
+#  define GDK_AudioMute 0x1008FF12
+#endif
+
+#ifndef GDK_AudioRaiseVolume
+#  define GDK_AudioRaiseVolume 0x1008FF13
+#endif
+
+#ifndef GDK_AudioPlay
+#  define GDK_AudioPlay 0x1008FF14
+#endif
+
+#ifndef GDK_AudioStop
+#  define GDK_AudioStop 0x1008FF15
+#endif
+
+#ifndef GDK_AudioPrev
+#  define GDK_AudioPrev 0x1008FF16
+#endif
+
+#ifndef GDK_AudioNext
+#  define GDK_AudioNext 0x1008FF17
+#endif
+
+#ifndef GDK_HomePage
+#  define GDK_HomePage 0x1008FF18
+#endif
+
+#ifndef GDK_Mail
+#  define GDK_Mail 0x1008FF19
+#endif
+
+#ifndef GDK_Search
+#  define GDK_Search 0x1008FF1B
+#endif
+
+#ifndef GDK_AudioRecord
+#  define GDK_AudioRecord 0x1008FF1C
+#endif
+
+#ifndef GDK_Back
+#  define GDK_Back 0x1008FF26
+#endif
+
+#ifndef GDK_Forward
+#  define GDK_Forward 0x1008FF27
+#endif
+
+#ifndef GDK_Stop
+#  define GDK_Stop 0x1008FF28
+#endif
+
+#ifndef GDK_Refresh
+#  define GDK_Refresh 0x1008FF29
+#endif
+
+#ifndef GDK_PowerOff
+#  define GDK_PowerOff 0x1008FF2A
+#endif
+
+#ifndef GDK_Eject
+#  define GDK_Eject 0x1008FF2C
+#endif
+
+#ifndef GDK_AudioPause
+#  define GDK_AudioPause 0x1008FF31
+#endif
+
+#ifndef GDK_BrightnessAdjust
+#  define GDK_BrightnessAdjust 0x1008FF3B
+#endif
+
+#ifndef GDK_AudioRewind
+#  define GDK_AudioRewind 0x1008FF3E
+#endif
+
+#ifndef GDK_Launch0
+#  define GDK_Launch0 0x1008FF40
+#endif
+
+#ifndef GDK_Launch1
+#  define GDK_Launch1 0x1008FF41
+#endif
+
+#ifndef GDK_Launch2
+#  define GDK_Launch2 0x1008FF42
+#endif
+
+#ifndef GDK_Launch3
+#  define GDK_Launch3 0x1008FF43
+#endif
+
+#ifndef GDK_Launch4
+#  define GDK_Launch4 0x1008FF44
+#endif
+
+#ifndef GDK_Launch5
+#  define GDK_Launch5 0x1008FF45
+#endif
+
+#ifndef GDK_Launch6
+#  define GDK_Launch6 0x1008FF46
+#endif
+
+#ifndef GDK_Launch7
+#  define GDK_Launch7 0x1008FF47
+#endif
+
+#ifndef GDK_Launch8
+#  define GDK_Launch8 0x1008FF48
+#endif
+
+#ifndef GDK_Launch9
+#  define GDK_Launch9 0x1008FF49
+#endif
+
+#ifndef GDK_LaunchA
+#  define GDK_LaunchA 0x1008FF4A
+#endif
+
+#ifndef GDK_LaunchB
+#  define GDK_LaunchB 0x1008FF4B
+#endif
+
+#ifndef GDK_LaunchC
+#  define GDK_LaunchC 0x1008FF4C
+#endif
+
+#ifndef GDK_LaunchD
+#  define GDK_LaunchD 0x1008FF4D
+#endif
+
+#ifndef GDK_LaunchE
+#  define GDK_LaunchE 0x1008FF4E
+#endif
+
+#ifndef GDK_LaunchF
+#  define GDK_LaunchF 0x1008FF4F
+#endif
+
+#ifndef GDK_Copy
+#  define GDK_Copy 0x1008FF57
+#endif
+
+#ifndef GDK_Cut
+#  define GDK_Cut 0x1008FF58
+#endif
+
+#ifndef GDK_Paste
+#  define GDK_Paste 0x1008FF6D
+#endif
+
+#ifndef GDK_Reload
+#  define GDK_Reload 0x1008FF73
+#endif
+
+#ifndef GDK_AudioRandomPlay
+#  define GDK_AudioRandomPlay 0x1008FF99
+#endif
+
+#ifndef GDK_Subtitle
+#  define GDK_Subtitle 0x1008FF9A
+#endif
+
+#ifndef GDK_Red
+#  define GDK_Red 0x1008FFA3
+#endif
+
+#ifndef GDK_Green
+#  define GDK_Green 0x1008FFA4
+#endif
+
+#ifndef GDK_Yellow
+#  define GDK_Yellow 0x1008FFA5
+#endif
+
+#ifndef GDK_Blue
+#  define GDK_Blue 0x1008FFA6
+#endif
+
+#ifndef GDK_TouchpadToggle
+#  define GDK_TouchpadToggle 0x1008FFA9
+#endif
+
+#ifndef GDK_TouchpadOn
+#  define GDK_TouchpadOn 0x1008FFB0
+#endif
+
+#ifndef GDK_TouchpadOff
+#  define GDK_TouchpadOff 0x1008ffb1
+#endif
+
+#ifndef GDK_LogWindowTree
+#  define GDK_LogWindowTree 0x1008FE24
+#endif
+
+#ifndef GDK_LogGrabInfo
+#  define GDK_LogGrabInfo 0x1008FE25
+#endif
+
+#ifndef GDK_Sleep
+#  define GDK_Sleep 0x1008FF2F
+#endif
+
+#endif /* GDKKEYSYMS_WRAPPER_H */
diff --git a/widget/gtk/compat/gdk/gdkvisual.h b/widget/gtk/compat/gdk/gdkvisual.h
new file mode 100644
index 0000000000..e5187a78da
--- /dev/null
+++ b/widget/gtk/compat/gdk/gdkvisual.h
@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GDKVISUAL_WRAPPER_H
+#define GDKVISUAL_WRAPPER_H
+
+#define gdk_visual_get_depth gdk_visual_get_depth_
+#include_next <gdk/gdkvisual.h>
+#undef gdk_visual_get_depth
+
+static inline gint gdk_visual_get_depth(GdkVisual* visual) {
+  return visual->depth;
+}
+#endif /* GDKVISUAL_WRAPPER_H */
diff --git a/widget/gtk/compat/gdk/gdkwindow.h b/widget/gtk/compat/gdk/gdkwindow.h
new file mode 100644
index 0000000000..a4d2efbc89
--- /dev/null
+++ b/widget/gtk/compat/gdk/gdkwindow.h
@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GDKWINDOW_WRAPPER_H
+#define GDKWINDOW_WRAPPER_H
+
+#define gdk_window_get_display gdk_window_get_display_
+#define gdk_window_get_screen gdk_window_get_screen_
+#include_next <gdk/gdkwindow.h>
+#undef gdk_window_get_display
+#undef gdk_window_get_screen
+
+static inline GdkDisplay* gdk_window_get_display(GdkWindow* window) {
+  return gdk_drawable_get_display(GDK_DRAWABLE(window));
+}
+
+static inline GdkScreen* gdk_window_get_screen(GdkWindow* window) {
+  return gdk_drawable_get_screen(window);
+}
+
+#if GDK_PIXBUF_MAJOR == 2 && GDK_PIXBUF_MINOR < 18
+static inline gboolean gdk_window_is_destroyed(GdkWindow* window) {
+  return GDK_WINDOW_OBJECT(window)->destroyed;
+}
+#endif
+#endif /* GDKWINDOW_WRAPPER_H */
diff --git a/widget/gtk/compat/gdk/gdkx.h b/widget/gtk/compat/gdk/gdkx.h
new file mode 100644
index 0000000000..7b0718f3cb
--- /dev/null
+++ b/widget/gtk/compat/gdk/gdkx.h
@@ -0,0 +1,42 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GDKX_WRAPPER_H
+#define GDKX_WRAPPER_H
+
+#include <gtk/gtkversion.h>
+
+#define gdk_x11_window_foreign_new_for_display \
+  gdk_x11_window_foreign_new_for_display_
+#define gdk_x11_window_lookup_for_display gdk_x11_window_lookup_for_display_
+#define gdk_x11_window_get_xid gdk_x11_window_get_xid_
+#if !GTK_CHECK_VERSION(2, 24, 0)
+#  define gdk_x11_set_sm_client_id gdk_x11_set_sm_client_id_
+#endif
+#include_next <gdk/gdkx.h>
+#undef gdk_x11_window_foreign_new_for_display
+#undef gdk_x11_window_lookup_for_display
+#undef gdk_x11_window_get_xid
+
+static inline GdkWindow* gdk_x11_window_foreign_new_for_display(
+    GdkDisplay* display, Window window) {
+  return gdk_window_foreign_new_for_display(display, window);
+}
+
+static inline GdkWindow* gdk_x11_window_lookup_for_display(GdkDisplay* display,
+                                                           Window window) {
+  return gdk_window_lookup_for_display(display, window);
+}
+
+static inline Window gdk_x11_window_get_xid(GdkWindow* window) {
+  return (GDK_WINDOW_XWINDOW(window));
+}
+
+#if !GTK_CHECK_VERSION(2, 24, 0)
+#  undef gdk_x11_set_sm_client_id
+static inline void gdk_x11_set_sm_client_id(const gchar* sm_client_id) {
+  gdk_set_sm_client_id(sm_client_id);
+}
+#endif
+#endif /* GDKX_WRAPPER_H */
diff --git a/widget/gtk/compat/glib/gmem.h b/widget/gtk/compat/glib/gmem.h
new file mode 100644
index 0000000000..78f24bbd8d
--- /dev/null
+++ b/widget/gtk/compat/glib/gmem.h
@@ -0,0 +1,48 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GMEM_WRAPPER_H
+#define GMEM_WRAPPER_H
+
+#define g_malloc_n g_malloc_n_
+#define g_malloc0_n g_malloc0_n_
+#define g_realloc_n g_realloc_n_
+#include_next <glib/gmem.h>
+#undef g_malloc_n
+#undef g_malloc0_n
+#undef g_realloc_n
+
+#include <glib/gmessages.h>
+
+#undef g_new
+#define g_new(type, num) ((type*)g_malloc_n((num), sizeof(type)))
+
+#undef g_new0
+#define g_new0(type, num) ((type*)g_malloc0_n((num), sizeof(type)))
+
+#undef g_renew
+#define g_renew(type, ptr, num) ((type*)g_realloc_n(ptr, (num), sizeof(type)))
+
+#define _CHECK_OVERFLOW(num, type_size)                                    \
+  if (G_UNLIKELY(type_size > 0 && num > G_MAXSIZE / type_size)) {          \
+    g_error("%s: overflow allocating %" G_GSIZE_FORMAT "*%" G_GSIZE_FORMAT \
+            " bytes",                                                      \
+            G_STRLOC, num, type_size);                                     \
+  }
+
+static inline gpointer g_malloc_n(gsize num, gsize type_size) {
+  _CHECK_OVERFLOW(num, type_size)
+  return g_malloc(num * type_size);
+}
+
+static inline gpointer g_malloc0_n(gsize num, gsize type_size) {
+  _CHECK_OVERFLOW(num, type_size)
+  return g_malloc0(num * type_size);
+}
+
+static inline gpointer g_realloc_n(gpointer ptr, gsize num, gsize type_size) {
+  _CHECK_OVERFLOW(num, type_size)
+  return g_realloc(ptr, num * type_size);
+}
+#endif /* GMEM_WRAPPER_H */
diff --git a/widget/gtk/compat/gtk/gtkwidget.h b/widget/gtk/compat/gtk/gtkwidget.h
new file mode 100644
index 0000000000..21165d61fa
--- /dev/null
+++ b/widget/gtk/compat/gtk/gtkwidget.h
@@ -0,0 +1,43 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GTKWIDGET_WRAPPER_H
+#define GTKWIDGET_WRAPPER_H
+
+#define gtk_widget_set_mapped gtk_widget_set_mapped_
+#define gtk_widget_get_mapped gtk_widget_get_mapped_
+#define gtk_widget_set_realized gtk_widget_set_realized_
+#define gtk_widget_get_realized gtk_widget_get_realized_
+#include_next <gtk/gtkwidget.h>
+#undef gtk_widget_set_mapped
+#undef gtk_widget_get_mapped
+#undef gtk_widget_set_realized
+#undef gtk_widget_get_realized
+
+#include <gtk/gtkversion.h>
+
+static inline void gtk_widget_set_mapped(GtkWidget* widget, gboolean mapped) {
+  if (mapped)
+    GTK_WIDGET_SET_FLAGS(widget, GTK_MAPPED);
+  else
+    GTK_WIDGET_UNSET_FLAGS(widget, GTK_MAPPED);
+}
+
+static inline gboolean gtk_widget_get_mapped(GtkWidget* widget) {
+  return GTK_WIDGET_MAPPED(widget);
+}
+
+static inline void gtk_widget_set_realized(GtkWidget* widget,
+                                           gboolean realized) {
+  if (realized)
+    GTK_WIDGET_SET_FLAGS(widget, GTK_REALIZED);
+  else
+    GTK_WIDGET_UNSET_FLAGS(widget, GTK_REALIZED);
+}
+
+static inline gboolean gtk_widget_get_realized(GtkWidget* widget) {
+  return GTK_WIDGET_REALIZED(widget);
+}
+
+#endif /* GTKWIDGET_WRAPPER_H */
diff --git a/widget/gtk/compat/gtk/gtkwindow.h b/widget/gtk/compat/gtk/gtkwindow.h
new file mode 100644
index 0000000000..7c3d5873bd
--- /dev/null
+++ b/widget/gtk/compat/gtk/gtkwindow.h
@@ -0,0 +1,26 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GTKWINDOW_WRAPPER_H
+#define GTKWINDOW_WRAPPER_H
+
+#define gtk_window_group_get_current_grab gtk_window_group_get_current_grab_
+#define gtk_window_get_window_type gtk_window_get_window_type_
+#include_next <gtk/gtkwindow.h>
+#undef gtk_window_group_get_current_grab
+#undef gtk_window_get_window_type
+
+static inline GtkWidget* gtk_window_group_get_current_grab(
+    GtkWindowGroup* window_group) {
+  if (!window_group->grabs) return NULL;
+
+  return GTK_WIDGET(window_group->grabs->data);
+}
+
+static inline GtkWindowType gtk_window_get_window_type(GtkWindow* window) {
+  gint type;
+  g_object_get(window, "type", &type, (void*)NULL);
+  return (GtkWindowType)type;
+}
+#endif /* GTKWINDOW_WRAPPER_H */
diff --git a/widget/gtk/components.conf b/widget/gtk/components.conf
new file mode 100644
index 0000000000..541df93378
--- /dev/null
+++ b/widget/gtk/components.conf
@@ -0,0 +1,151 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Headers = [
+    '/widget/gtk/nsWidgetFactory.h',
+]
+
+InitFunc = 'nsWidgetGtk2ModuleCtor'
+UnloadFunc = 'nsWidgetGtk2ModuleDtor'
+
+Classes = [
+    {
+        'cid': '{2d96b3df-c051-11d1-a827-0040959a28c9}',
+        'contract_ids': ['@mozilla.org/widget/appshell/gtk;1'],
+        'legacy_constructor': 'nsAppShellConstructor',
+        'headers': ['/widget/gtk/nsWidgetFactory.h'],
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_UTILITY_AND_GMPLUGIN_PROCESS,
+    },
+    {
+        'cid': '{e9537f8f-c07e-4435-8ab3-83f1ad6e3bbf}',
+        'contract_ids': ['@mozilla.org/gfx/parent/screenmanager;1'],
+        'singleton': True,
+        'type': 'mozilla::widget::ScreenManager',
+        'headers': ['mozilla/StaticPtr.h', 'mozilla/widget/ScreenManager.h'],
+        'constructor': 'mozilla::widget::ScreenManager::GetAddRefedSingleton',
+        'processes': ProcessSelector.ALLOW_IN_GPU_AND_MAIN_PROCESS,
+    },
+    {
+        'cid': '{a9339876-0027-430f-b953-84c9c11c2da3}',
+        'contract_ids': ['@mozilla.org/widget/taskbarprogress/gtk;1'],
+        'type': 'TaskbarProgress',
+        'headers': ['/widget/gtk/TaskbarProgress.h'],
+    },
+    {
+        'cid': '{4364de1a-798e-419c-a6f5-ca28866b6d5f}',
+        'contract_ids': ['@mozilla.org/parent/colorpicker;1'],
+        'type': 'nsColorPicker',
+        'headers': ['/widget/gtk/nsColorPicker.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{1940fed5-7d02-4122-8acf-7abaac698983}',
+        'contract_ids': ['@mozilla.org/parent/filepicker;1'],
+        'type': 'nsFilePicker',
+        'headers': ['/widget/gtk/nsFilePicker.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{948a0023-e3a7-11d2-96cf-0060b0fb9956}',
+        'contract_ids': ['@mozilla.org/widget/htmlformatconverter;1'],
+        'type': 'nsHTMLFormatConverter',
+        'headers': ['/widget/nsHTMLFormatConverter.h'],
+    },
+    {
+        'cid': '{b148eed2-236d-11d3-b35c-00a0cc3c1cde}',
+        'contract_ids': ['@mozilla.org/sound;1'],
+        'singleton': True,
+        'type': 'nsISound',
+        'constructor': 'nsSound::GetInstance',
+        'headers': ['/widget/gtk/nsSound.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{8b5314bc-db01-11d2-96ce-0060b0fb9956}',
+        'contract_ids': ['@mozilla.org/widget/transferable;1'],
+        'type': 'nsTransferable',
+        'headers': ['/widget/nsTransferable.h'],
+    },
+    {
+        'cid': '{e221df9b-3d66-4045-9a66-5720949f8d10}',
+        'contract_ids': ['@mozilla.org/applicationchooser;1'],
+        'type': 'nsApplicationChooser',
+        'headers': ['/widget/gtk/nsApplicationChooser.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{f55f5d31-dbb7-4d0d-9f6f-a4f4cd8e8ef1}',
+        'contract_ids': ['@mozilla.org/widget/parent/clipboard;1'],
+        'interfaces': ['nsIClipboard'],
+        'type': 'nsIClipboard',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{77221d5a-1dd2-11b2-8c69-c710f15d2ed5}',
+        'contract_ids': ['@mozilla.org/widget/clipboardhelper;1'],
+        'type': 'nsClipboardHelper',
+        'headers': ['/widget/nsClipboardHelper.h'],
+    },
+    {
+        'cid': '{0ba77e04-2adb-422f-af01-5a57b8013100}',
+        'contract_ids': ['@mozilla.org/widget/parent/dragservice;1'],
+        'singleton': True,
+        'type': 'nsDragService',
+        'headers': ['/widget/gtk/nsDragService.h'],
+        'constructor': 'nsDragService::GetInstance',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'name': 'GfxInfo',
+        'cid': '{d755a760-9f27-11df-0800-200c9a664242}',
+        'contract_ids': ['@mozilla.org/gfx/info;1'],
+        'type': 'mozilla::widget::GfxInfo',
+        'headers': ['/widget/gtk/GfxInfo.h'],
+        'init_method': 'Init',
+        'processes': ProcessSelector.ALLOW_IN_GPU_PROCESS,
+    },
+    {
+        'cid': '{6987230e-0098-4e78-bc5f-1493ee7519fa}',
+        'contract_ids': ['@mozilla.org/widget/useridleservice;1'],
+        'singleton': True,
+        'type': 'nsUserIdleService',
+        'headers': ['/widget/gtk/nsUserIdleServiceGTK.h'],
+        'constructor': 'nsUserIdleServiceGTK::GetInstance',
+    },
+]
+
+if defined('NS_PRINTING'):
+    Classes += [
+        {
+            'cid': '{d3f69889-e13a-4321-980c-a39332e21f34}',
+            'contract_ids': ['@mozilla.org/gfx/devicecontextspec;1'],
+            'type': 'nsDeviceContextSpecGTK',
+            'headers': ['/widget/gtk/nsDeviceContextSpecG.h'],
+            'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        },
+        {
+            'cid': '{06beec76-a183-4d9f-85dd-085f26da565a}',
+            'contract_ids': ['@mozilla.org/widget/printdialog-service;1'],
+            'type': 'nsPrintDialogServiceGTK',
+            'headers': ['/widget/gtk/nsPrintDialogGTK.h'],
+            'init_method': 'Init',
+            'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        },
+        {
+            'cid': '{841387c8-72e6-484b-9296-bf6eea80d58a}',
+            'contract_ids': ['@mozilla.org/gfx/printsettings-service;1'],
+            'type': 'nsPrintSettingsServiceGTK',
+            'headers': ['/widget/gtk/nsPrintSettingsServiceGTK.h'],
+            'init_method': 'Init',
+        },
+        {
+            'cid': '{a6cf9129-15b3-11d2-932e-00805f8add32}',
+            'contract_ids': ['@mozilla.org/gfx/printerlist;1'],
+            'type': 'nsPrinterListCUPS',
+            'headers': ['/widget/nsPrinterListCUPS.h'],
+            'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        },
+    ]
diff --git a/widget/gtk/crashtests/540078-1.xhtml b/widget/gtk/crashtests/540078-1.xhtml
new file mode 100644
index 0000000000..f5de1b9aee
--- /dev/null
+++ b/widget/gtk/crashtests/540078-1.xhtml
@@ -0,0 +1 @@
+<html xmlns="http://www.w3.org/1999/xhtml"><hbox xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"><scrollcorner class="zebra"/></hbox><style style="display: none;">.zebra { -moz-appearance: checkbox; }</style></html>
diff --git a/widget/gtk/crashtests/673390-1.html b/widget/gtk/crashtests/673390-1.html
new file mode 100644
index 0000000000..8463f67f05
--- /dev/null
+++ b/widget/gtk/crashtests/673390-1.html
@@ -0,0 +1 @@
+<div style="-moz-appearance: progresschunk; position: fixed"></div>
diff --git a/widget/gtk/crashtests/crashtests.list b/widget/gtk/crashtests/crashtests.list
new file mode 100644
index 0000000000..9ae47c2233
--- /dev/null
+++ b/widget/gtk/crashtests/crashtests.list
@@ -0,0 +1,2 @@
+load 540078-1.xhtml
+load 673390-1.html
diff --git a/widget/gtk/gbm.h b/widget/gtk/gbm.h
new file mode 100644
index 0000000000..bd94fa8967
--- /dev/null
+++ b/widget/gtk/gbm.h
@@ -0,0 +1,480 @@
+/*
+ * Copyright © 2011 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Benjamin Franzke <benjaminfranzke@googlemail.com>
+ */
+
+#ifndef _GBM_H_
+#define _GBM_H_
+
+#define __GBM__ 1
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \file gbm.h
+ * \brief Generic Buffer Manager
+ */
+
+struct gbm_device;
+struct gbm_bo;
+struct gbm_surface;
+
+/**
+ * \mainpage The Generic Buffer Manager
+ *
+ * This module provides an abstraction that the caller can use to request a
+ * buffer from the underlying memory management system for the platform.
+ *
+ * This allows the creation of portable code whilst still allowing access to
+ * the underlying memory manager.
+ */
+
+/**
+ * Abstraction representing the handle to a buffer allocated by the
+ * manager
+ */
+union gbm_bo_handle {
+  void* ptr;
+  int32_t s32;
+  uint32_t u32;
+  int64_t s64;
+  uint64_t u64;
+};
+
+/** Format of the allocated buffer */
+enum gbm_bo_format {
+  /** RGB with 8 bits per channel in a 32 bit value */
+  GBM_BO_FORMAT_XRGB8888,
+  /** ARGB with 8 bits per channel in a 32 bit value */
+  GBM_BO_FORMAT_ARGB8888
+};
+
+/**
+ * The FourCC format codes are taken from the drm_fourcc.h definition, and
+ * re-namespaced. New GBM formats must not be added, unless they are
+ * identical ports from drm_fourcc.
+ */
+#define __gbm_fourcc_code(a, b, c, d)                             \
+  ((uint32_t)(a) | ((uint32_t)(b) << 8) | ((uint32_t)(c) << 16) | \
+   ((uint32_t)(d) << 24))
+
+#define GBM_FORMAT_BIG_ENDIAN \
+  (1 << 31) /* format is big endian instead of little endian */
+
+/* color index */
+#define GBM_FORMAT_C8 __gbm_fourcc_code('C', '8', ' ', ' ') /* [7:0] C */
+
+/* 8 bpp Red */
+#define GBM_FORMAT_R8 __gbm_fourcc_code('R', '8', ' ', ' ') /* [7:0] R */
+
+/* 16 bpp RG */
+#define GBM_FORMAT_GR88 \
+  __gbm_fourcc_code('G', 'R', '8', '8') /* [15:0] G:R 8:8 little endian */
+
+/* 8 bpp RGB */
+#define GBM_FORMAT_RGB332 \
+  __gbm_fourcc_code('R', 'G', 'B', '8') /* [7:0] R:G:B 3:3:2 */
+#define GBM_FORMAT_BGR233 \
+  __gbm_fourcc_code('B', 'G', 'R', '8') /* [7:0] B:G:R 2:3:3 */
+
+/* 16 bpp RGB */
+#define GBM_FORMAT_XRGB4444        \
+  __gbm_fourcc_code('X', 'R', '1', \
+                    '2') /* [15:0] x:R:G:B 4:4:4:4 little endian */
+#define GBM_FORMAT_XBGR4444        \
+  __gbm_fourcc_code('X', 'B', '1', \
+                    '2') /* [15:0] x:B:G:R 4:4:4:4 little endian */
+#define GBM_FORMAT_RGBX4444        \
+  __gbm_fourcc_code('R', 'X', '1', \
+                    '2') /* [15:0] R:G:B:x 4:4:4:4 little endian */
+#define GBM_FORMAT_BGRX4444        \
+  __gbm_fourcc_code('B', 'X', '1', \
+                    '2') /* [15:0] B:G:R:x 4:4:4:4 little endian */
+
+#define GBM_FORMAT_ARGB4444        \
+  __gbm_fourcc_code('A', 'R', '1', \
+                    '2') /* [15:0] A:R:G:B 4:4:4:4 little endian */
+#define GBM_FORMAT_ABGR4444        \
+  __gbm_fourcc_code('A', 'B', '1', \
+                    '2') /* [15:0] A:B:G:R 4:4:4:4 little endian */
+#define GBM_FORMAT_RGBA4444        \
+  __gbm_fourcc_code('R', 'A', '1', \
+                    '2') /* [15:0] R:G:B:A 4:4:4:4 little endian */
+#define GBM_FORMAT_BGRA4444        \
+  __gbm_fourcc_code('B', 'A', '1', \
+                    '2') /* [15:0] B:G:R:A 4:4:4:4 little endian */
+
+#define GBM_FORMAT_XRGB1555        \
+  __gbm_fourcc_code('X', 'R', '1', \
+                    '5') /* [15:0] x:R:G:B 1:5:5:5 little endian */
+#define GBM_FORMAT_XBGR1555        \
+  __gbm_fourcc_code('X', 'B', '1', \
+                    '5') /* [15:0] x:B:G:R 1:5:5:5 little endian */
+#define GBM_FORMAT_RGBX5551        \
+  __gbm_fourcc_code('R', 'X', '1', \
+                    '5') /* [15:0] R:G:B:x 5:5:5:1 little endian */
+#define GBM_FORMAT_BGRX5551        \
+  __gbm_fourcc_code('B', 'X', '1', \
+                    '5') /* [15:0] B:G:R:x 5:5:5:1 little endian */
+
+#define GBM_FORMAT_ARGB1555        \
+  __gbm_fourcc_code('A', 'R', '1', \
+                    '5') /* [15:0] A:R:G:B 1:5:5:5 little endian */
+#define GBM_FORMAT_ABGR1555        \
+  __gbm_fourcc_code('A', 'B', '1', \
+                    '5') /* [15:0] A:B:G:R 1:5:5:5 little endian */
+#define GBM_FORMAT_RGBA5551        \
+  __gbm_fourcc_code('R', 'A', '1', \
+                    '5') /* [15:0] R:G:B:A 5:5:5:1 little endian */
+#define GBM_FORMAT_BGRA5551        \
+  __gbm_fourcc_code('B', 'A', '1', \
+                    '5') /* [15:0] B:G:R:A 5:5:5:1 little endian */
+
+#define GBM_FORMAT_RGB565 \
+  __gbm_fourcc_code('R', 'G', '1', '6') /* [15:0] R:G:B 5:6:5 little endian */
+#define GBM_FORMAT_BGR565 \
+  __gbm_fourcc_code('B', 'G', '1', '6') /* [15:0] B:G:R 5:6:5 little endian */
+
+/* 24 bpp RGB */
+#define GBM_FORMAT_RGB888 \
+  __gbm_fourcc_code('R', 'G', '2', '4') /* [23:0] R:G:B little endian */
+#define GBM_FORMAT_BGR888 \
+  __gbm_fourcc_code('B', 'G', '2', '4') /* [23:0] B:G:R little endian */
+
+/* 32 bpp RGB */
+#define GBM_FORMAT_XRGB8888        \
+  __gbm_fourcc_code('X', 'R', '2', \
+                    '4') /* [31:0] x:R:G:B 8:8:8:8 little endian */
+#define GBM_FORMAT_XBGR8888        \
+  __gbm_fourcc_code('X', 'B', '2', \
+                    '4') /* [31:0] x:B:G:R 8:8:8:8 little endian */
+#define GBM_FORMAT_RGBX8888        \
+  __gbm_fourcc_code('R', 'X', '2', \
+                    '4') /* [31:0] R:G:B:x 8:8:8:8 little endian */
+#define GBM_FORMAT_BGRX8888        \
+  __gbm_fourcc_code('B', 'X', '2', \
+                    '4') /* [31:0] B:G:R:x 8:8:8:8 little endian */
+
+#define GBM_FORMAT_ARGB8888        \
+  __gbm_fourcc_code('A', 'R', '2', \
+                    '4') /* [31:0] A:R:G:B 8:8:8:8 little endian */
+#define GBM_FORMAT_ABGR8888        \
+  __gbm_fourcc_code('A', 'B', '2', \
+                    '4') /* [31:0] A:B:G:R 8:8:8:8 little endian */
+#define GBM_FORMAT_RGBA8888        \
+  __gbm_fourcc_code('R', 'A', '2', \
+                    '4') /* [31:0] R:G:B:A 8:8:8:8 little endian */
+#define GBM_FORMAT_BGRA8888        \
+  __gbm_fourcc_code('B', 'A', '2', \
+                    '4') /* [31:0] B:G:R:A 8:8:8:8 little endian */
+
+#define GBM_FORMAT_XRGB2101010     \
+  __gbm_fourcc_code('X', 'R', '3', \
+                    '0') /* [31:0] x:R:G:B 2:10:10:10 little endian */
+#define GBM_FORMAT_XBGR2101010     \
+  __gbm_fourcc_code('X', 'B', '3', \
+                    '0') /* [31:0] x:B:G:R 2:10:10:10 little endian */
+#define GBM_FORMAT_RGBX1010102     \
+  __gbm_fourcc_code('R', 'X', '3', \
+                    '0') /* [31:0] R:G:B:x 10:10:10:2 little endian */
+#define GBM_FORMAT_BGRX1010102     \
+  __gbm_fourcc_code('B', 'X', '3', \
+                    '0') /* [31:0] B:G:R:x 10:10:10:2 little endian */
+
+#define GBM_FORMAT_ARGB2101010     \
+  __gbm_fourcc_code('A', 'R', '3', \
+                    '0') /* [31:0] A:R:G:B 2:10:10:10 little endian */
+#define GBM_FORMAT_ABGR2101010     \
+  __gbm_fourcc_code('A', 'B', '3', \
+                    '0') /* [31:0] A:B:G:R 2:10:10:10 little endian */
+#define GBM_FORMAT_RGBA1010102     \
+  __gbm_fourcc_code('R', 'A', '3', \
+                    '0') /* [31:0] R:G:B:A 10:10:10:2 little endian */
+#define GBM_FORMAT_BGRA1010102     \
+  __gbm_fourcc_code('B', 'A', '3', \
+                    '0') /* [31:0] B:G:R:A 10:10:10:2 little endian */
+
+/* packed YCbCr */
+#define GBM_FORMAT_YUYV            \
+  __gbm_fourcc_code('Y', 'U', 'Y', \
+                    'V') /* [31:0] Cr0:Y1:Cb0:Y0 8:8:8:8 little endian */
+#define GBM_FORMAT_YVYU            \
+  __gbm_fourcc_code('Y', 'V', 'Y', \
+                    'U') /* [31:0] Cb0:Y1:Cr0:Y0 8:8:8:8 little endian */
+#define GBM_FORMAT_UYVY            \
+  __gbm_fourcc_code('U', 'Y', 'V', \
+                    'Y') /* [31:0] Y1:Cr0:Y0:Cb0 8:8:8:8 little endian */
+#define GBM_FORMAT_VYUY            \
+  __gbm_fourcc_code('V', 'Y', 'U', \
+                    'Y') /* [31:0] Y1:Cb0:Y0:Cr0 8:8:8:8 little endian */
+
+#define GBM_FORMAT_AYUV            \
+  __gbm_fourcc_code('A', 'Y', 'U', \
+                    'V') /* [31:0] A:Y:Cb:Cr 8:8:8:8 little endian */
+
+/*
+ * 2 plane YCbCr
+ * index 0 = Y plane, [7:0] Y
+ * index 1 = Cr:Cb plane, [15:0] Cr:Cb little endian
+ * or
+ * index 1 = Cb:Cr plane, [15:0] Cb:Cr little endian
+ */
+#define GBM_FORMAT_NV12 \
+  __gbm_fourcc_code('N', 'V', '1', '2') /* 2x2 subsampled Cr:Cb plane */
+#define GBM_FORMAT_NV21 \
+  __gbm_fourcc_code('N', 'V', '2', '1') /* 2x2 subsampled Cb:Cr plane */
+#define GBM_FORMAT_NV16 \
+  __gbm_fourcc_code('N', 'V', '1', '6') /* 2x1 subsampled Cr:Cb plane */
+#define GBM_FORMAT_NV61 \
+  __gbm_fourcc_code('N', 'V', '6', '1') /* 2x1 subsampled Cb:Cr plane */
+
+/*
+ * 3 plane YCbCr
+ * index 0: Y plane, [7:0] Y
+ * index 1: Cb plane, [7:0] Cb
+ * index 2: Cr plane, [7:0] Cr
+ * or
+ * index 1: Cr plane, [7:0] Cr
+ * index 2: Cb plane, [7:0] Cb
+ */
+#define GBM_FORMAT_YUV410          \
+  __gbm_fourcc_code('Y', 'U', 'V', \
+                    '9') /* 4x4 subsampled Cb (1) and Cr (2) planes */
+#define GBM_FORMAT_YVU410          \
+  __gbm_fourcc_code('Y', 'V', 'U', \
+                    '9') /* 4x4 subsampled Cr (1) and Cb (2) planes */
+#define GBM_FORMAT_YUV411          \
+  __gbm_fourcc_code('Y', 'U', '1', \
+                    '1') /* 4x1 subsampled Cb (1) and Cr (2) planes */
+#define GBM_FORMAT_YVU411          \
+  __gbm_fourcc_code('Y', 'V', '1', \
+                    '1') /* 4x1 subsampled Cr (1) and Cb (2) planes */
+#define GBM_FORMAT_YUV420          \
+  __gbm_fourcc_code('Y', 'U', '1', \
+                    '2') /* 2x2 subsampled Cb (1) and Cr (2) planes */
+#define GBM_FORMAT_YVU420          \
+  __gbm_fourcc_code('Y', 'V', '1', \
+                    '2') /* 2x2 subsampled Cr (1) and Cb (2) planes */
+#define GBM_FORMAT_YUV422          \
+  __gbm_fourcc_code('Y', 'U', '1', \
+                    '6') /* 2x1 subsampled Cb (1) and Cr (2) planes */
+#define GBM_FORMAT_YVU422          \
+  __gbm_fourcc_code('Y', 'V', '1', \
+                    '6') /* 2x1 subsampled Cr (1) and Cb (2) planes */
+#define GBM_FORMAT_YUV444          \
+  __gbm_fourcc_code('Y', 'U', '2', \
+                    '4') /* non-subsampled Cb (1) and Cr (2) planes */
+#define GBM_FORMAT_YVU444          \
+  __gbm_fourcc_code('Y', 'V', '2', \
+                    '4') /* non-subsampled Cr (1) and Cb (2) planes */
+
+struct gbm_format_name_desc {
+  char name[5];
+};
+
+/**
+ * Flags to indicate the intended use for the buffer - these are passed into
+ * gbm_bo_create(). The caller must set the union of all the flags that are
+ * appropriate
+ *
+ * \sa Use gbm_device_is_format_supported() to check if the combination of
+ * format and use flags are supported
+ */
+enum gbm_bo_flags {
+  /**
+   * Buffer is going to be presented to the screen using an API such as KMS
+   */
+  GBM_BO_USE_SCANOUT = (1 << 0),
+  /**
+   * Buffer is going to be used as cursor
+   */
+  GBM_BO_USE_CURSOR = (1 << 1),
+  /**
+   * Deprecated
+   */
+  GBM_BO_USE_CURSOR_64X64 = GBM_BO_USE_CURSOR,
+  /**
+   * Buffer is to be used for rendering - for example it is going to be used
+   * as the storage for a color buffer
+   */
+  GBM_BO_USE_RENDERING = (1 << 2),
+  /**
+   * Buffer can be used for gbm_bo_write.  This is guaranteed to work
+   * with GBM_BO_USE_CURSOR, but may not work for other combinations.
+   */
+  GBM_BO_USE_WRITE = (1 << 3),
+  /**
+   * Buffer is linear, i.e. not tiled.
+   */
+  GBM_BO_USE_LINEAR = (1 << 4),
+};
+
+int gbm_device_get_fd(struct gbm_device* gbm);
+
+const char* gbm_device_get_backend_name(struct gbm_device* gbm);
+
+int gbm_device_is_format_supported(struct gbm_device* gbm, uint32_t format,
+                                   uint32_t usage);
+
+int gbm_device_get_format_modifier_plane_count(struct gbm_device* gbm,
+                                               uint32_t format,
+                                               uint64_t modifier);
+
+void gbm_device_destroy(struct gbm_device* gbm);
+
+struct gbm_device* gbm_create_device(int fd);
+
+struct gbm_bo* gbm_bo_create(struct gbm_device* gbm, uint32_t width,
+                             uint32_t height, uint32_t format, uint32_t flags);
+
+struct gbm_bo* gbm_bo_create_with_modifiers(struct gbm_device* gbm,
+                                            uint32_t width, uint32_t height,
+                                            uint32_t format,
+                                            const uint64_t* modifiers,
+                                            const unsigned int count);
+#define GBM_BO_IMPORT_WL_BUFFER 0x5501
+#define GBM_BO_IMPORT_EGL_IMAGE 0x5502
+#define GBM_BO_IMPORT_FD 0x5503
+#define GBM_BO_IMPORT_FD_MODIFIER 0x5504
+
+struct gbm_import_fd_data {
+  int fd;
+  uint32_t width;
+  uint32_t height;
+  uint32_t stride;
+  uint32_t format;
+};
+
+struct gbm_import_fd_modifier_data {
+  uint32_t width;
+  uint32_t height;
+  uint32_t format;
+  uint32_t num_fds;
+  int fds[4];
+  int strides[4];
+  int offsets[4];
+  uint64_t modifier;
+};
+
+struct gbm_bo* gbm_bo_import(struct gbm_device* gbm, uint32_t type,
+                             void* buffer, uint32_t usage);
+
+/**
+ * Flags to indicate the type of mapping for the buffer - these are
+ * passed into gbm_bo_map(). The caller must set the union of all the
+ * flags that are appropriate.
+ *
+ * These flags are independent of the GBM_BO_USE_* creation flags. However,
+ * mapping the buffer may require copying to/from a staging buffer.
+ *
+ * See also: pipe_transfer_usage
+ */
+enum gbm_bo_transfer_flags {
+  /**
+   * Buffer contents read back (or accessed directly) at transfer
+   * create time.
+   */
+  GBM_BO_TRANSFER_READ = (1 << 0),
+  /**
+   * Buffer contents will be written back at unmap time
+   * (or modified as a result of being accessed directly).
+   */
+  GBM_BO_TRANSFER_WRITE = (1 << 1),
+  /**
+   * Read/modify/write
+   */
+  GBM_BO_TRANSFER_READ_WRITE = (GBM_BO_TRANSFER_READ | GBM_BO_TRANSFER_WRITE),
+};
+
+void* gbm_bo_map(struct gbm_bo* bo, uint32_t x, uint32_t y, uint32_t width,
+                 uint32_t height, uint32_t flags, uint32_t* stride,
+                 void** map_data);
+
+void gbm_bo_unmap(struct gbm_bo* bo, void* map_data);
+
+uint32_t gbm_bo_get_width(struct gbm_bo* bo);
+
+uint32_t gbm_bo_get_height(struct gbm_bo* bo);
+
+uint32_t gbm_bo_get_stride(struct gbm_bo* bo);
+
+uint32_t gbm_bo_get_stride_for_plane(struct gbm_bo* bo, int plane);
+
+uint32_t gbm_bo_get_format(struct gbm_bo* bo);
+
+uint32_t gbm_bo_get_bpp(struct gbm_bo* bo);
+
+uint32_t gbm_bo_get_offset(struct gbm_bo* bo, int plane);
+
+struct gbm_device* gbm_bo_get_device(struct gbm_bo* bo);
+
+union gbm_bo_handle gbm_bo_get_handle(struct gbm_bo* bo);
+
+int gbm_bo_get_fd(struct gbm_bo* bo);
+
+uint64_t gbm_bo_get_modifier(struct gbm_bo* bo);
+
+int gbm_bo_get_plane_count(struct gbm_bo* bo);
+
+union gbm_bo_handle gbm_bo_get_handle_for_plane(struct gbm_bo* bo, int plane);
+
+int gbm_bo_write(struct gbm_bo* bo, const void* buf, size_t count);
+
+void gbm_bo_set_user_data(struct gbm_bo* bo, void* data,
+                          void (*destroy_user_data)(struct gbm_bo*, void*));
+
+void* gbm_bo_get_user_data(struct gbm_bo* bo);
+
+void gbm_bo_destroy(struct gbm_bo* bo);
+
+struct gbm_surface* gbm_surface_create(struct gbm_device* gbm, uint32_t width,
+                                       uint32_t height, uint32_t format,
+                                       uint32_t flags);
+
+struct gbm_surface* gbm_surface_create_with_modifiers(
+    struct gbm_device* gbm, uint32_t width, uint32_t height, uint32_t format,
+    const uint64_t* modifiers, const unsigned int count);
+
+struct gbm_bo* gbm_surface_lock_front_buffer(struct gbm_surface* surface);
+
+void gbm_surface_release_buffer(struct gbm_surface* surface, struct gbm_bo* bo);
+
+int gbm_surface_has_free_buffers(struct gbm_surface* surface);
+
+void gbm_surface_destroy(struct gbm_surface* surface);
+
+char* gbm_format_get_name(uint32_t gbm_format,
+                          struct gbm_format_name_desc* desc);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/widget/gtk/gtk3drawing.cpp b/widget/gtk/gtk3drawing.cpp
new file mode 100644
index 0000000000..1fa8b95606
--- /dev/null
+++ b/widget/gtk/gtk3drawing.cpp
@@ -0,0 +1,2179 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * This file contains painting functions for each of the gtk2 widgets.
+ * Adapted from the gtkdrawing.c, and gtk+2.0 source.
+ */
+
+#include <gtk/gtk.h>
+#include <gdk/gdkprivate.h>
+#include <string.h>
+#include "gtkdrawing.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/ScopeExit.h"
+#include "prinrval.h"
+#include "WidgetStyleCache.h"
+#include "nsString.h"
+#include "nsDebug.h"
+#include "WidgetUtilsGtk.h"
+
+#include <math.h>
+#include <dlfcn.h>
+
+static gboolean checkbox_check_state;
+static gboolean notebook_has_tab_gap;
+
+static ToggleGTKMetrics sCheckboxMetrics;
+static ToggleGTKMetrics sRadioMetrics;
+static ToolbarGTKMetrics sToolbarMetrics;
+static CSDWindowDecorationSize sToplevelWindowDecorationSize;
+static CSDWindowDecorationSize sPopupWindowDecorationSize;
+
+using mozilla::Span;
+
+#define ARROW_UP 0
+#define ARROW_DOWN G_PI
+#define ARROW_RIGHT G_PI_2
+#define ARROW_LEFT (G_PI + G_PI_2)
+
+#if 0
+// It's used for debugging only to compare Gecko widget style with
+// the ones used by Gtk+ applications.
+static void
+style_path_print(GtkStyleContext *context)
+{
+    const GtkWidgetPath* path = gtk_style_context_get_path(context);
+
+    static auto sGtkWidgetPathToStringPtr =
+        (char * (*)(const GtkWidgetPath *))
+        dlsym(RTLD_DEFAULT, "gtk_widget_path_to_string");
+
+    fprintf(stderr, "Style path:\n%s\n\n", sGtkWidgetPathToStringPtr(path));
+}
+#endif
+
+static GtkBorder operator+=(GtkBorder& first, const GtkBorder& second) {
+  first.left += second.left;
+  first.right += second.right;
+  first.top += second.top;
+  first.bottom += second.bottom;
+  return first;
+}
+
+static gint moz_gtk_get_tab_thickness(GtkStyleContext* style);
+
+static void Inset(GdkRectangle*, const GtkBorder&);
+
+static void InsetByMargin(GdkRectangle*, GtkStyleContext* style);
+
+static void moz_gtk_add_style_margin(GtkStyleContext* style, gint* left,
+                                     gint* top, gint* right, gint* bottom) {
+  GtkBorder margin;
+
+  gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
+                               &margin);
+  *left += margin.left;
+  *right += margin.right;
+  *top += margin.top;
+  *bottom += margin.bottom;
+}
+
+static void moz_gtk_add_style_border(GtkStyleContext* style, gint* left,
+                                     gint* top, gint* right, gint* bottom) {
+  GtkBorder border;
+
+  gtk_style_context_get_border(style, gtk_style_context_get_state(style),
+                               &border);
+
+  *left += border.left;
+  *right += border.right;
+  *top += border.top;
+  *bottom += border.bottom;
+}
+
+static void moz_gtk_add_style_padding(GtkStyleContext* style, gint* left,
+                                      gint* top, gint* right, gint* bottom) {
+  GtkBorder padding;
+
+  gtk_style_context_get_padding(style, gtk_style_context_get_state(style),
+                                &padding);
+
+  *left += padding.left;
+  *right += padding.right;
+  *top += padding.top;
+  *bottom += padding.bottom;
+}
+
+static void moz_gtk_add_margin_border_padding(GtkStyleContext* style,
+                                              gint* left, gint* top,
+                                              gint* right, gint* bottom) {
+  moz_gtk_add_style_margin(style, left, top, right, bottom);
+  moz_gtk_add_style_border(style, left, top, right, bottom);
+  moz_gtk_add_style_padding(style, left, top, right, bottom);
+}
+
+static void moz_gtk_add_border_padding(GtkStyleContext* style, gint* left,
+                                       gint* top, gint* right, gint* bottom) {
+  moz_gtk_add_style_border(style, left, top, right, bottom);
+  moz_gtk_add_style_padding(style, left, top, right, bottom);
+}
+
+// In case there's an error in Gtk theme and preferred size is zero,
+// return some sane values to pass mozilla automation tests.
+// It should not happen in real-life.
+#define MIN_WIDGET_SIZE 10
+static void moz_gtk_sanity_preferred_size(GtkRequisition* requisition) {
+  if (requisition->width <= 0) {
+    requisition->width = MIN_WIDGET_SIZE;
+  }
+  if (requisition->height <= 0) {
+    requisition->height = MIN_WIDGET_SIZE;
+  }
+}
+
+// GetStateFlagsFromGtkWidgetState() can be safely used for the specific
+// GtkWidgets that set both prelight and active flags.  For other widgets,
+// either the GtkStateFlags or Gecko's GtkWidgetState need to be carefully
+// adjusted to match GTK behavior.  Although GTK sets insensitive and focus
+// flags in the generic GtkWidget base class, GTK adds prelight and active
+// flags only to widgets that are expected to demonstrate prelight or active
+// states.  This contrasts with HTML where any element may have :active and
+// :hover states, and so Gecko's GtkStateFlags do not necessarily map to GTK
+// flags.  Failure to restrict the flags in the same way as GTK can cause
+// generic CSS selectors from some themes to unintentionally match elements
+// that are not expected to change appearance on hover or mouse-down.
+static GtkStateFlags GetStateFlagsFromGtkWidgetState(GtkWidgetState* state) {
+  GtkStateFlags stateFlags = GTK_STATE_FLAG_NORMAL;
+
+  if (state->disabled)
+    stateFlags = GTK_STATE_FLAG_INSENSITIVE;
+  else {
+    if (state->depressed || state->active)
+      stateFlags =
+          static_cast<GtkStateFlags>(stateFlags | GTK_STATE_FLAG_ACTIVE);
+    if (state->inHover)
+      stateFlags =
+          static_cast<GtkStateFlags>(stateFlags | GTK_STATE_FLAG_PRELIGHT);
+    if (state->focused)
+      stateFlags =
+          static_cast<GtkStateFlags>(stateFlags | GTK_STATE_FLAG_FOCUSED);
+    if (state->backdrop)
+      stateFlags =
+          static_cast<GtkStateFlags>(stateFlags | GTK_STATE_FLAG_BACKDROP);
+  }
+
+  return stateFlags;
+}
+
+static GtkStateFlags GetStateFlagsFromGtkTabFlags(GtkTabFlags flags) {
+  return ((flags & MOZ_GTK_TAB_SELECTED) == 0) ? GTK_STATE_FLAG_NORMAL
+                                               : GTK_STATE_FLAG_ACTIVE;
+}
+
+gint moz_gtk_init() {
+  if (gtk_major_version > 3 ||
+      (gtk_major_version == 3 && gtk_minor_version >= 14))
+    checkbox_check_state = GTK_STATE_FLAG_CHECKED;
+  else
+    checkbox_check_state = GTK_STATE_FLAG_ACTIVE;
+
+  moz_gtk_refresh();
+
+  return MOZ_GTK_SUCCESS;
+}
+
+void moz_gtk_refresh() {
+  if (gtk_check_version(3, 20, 0) != nullptr) {
+    // Deprecated for Gtk >= 3.20+
+    GtkStyleContext* style = GetStyleContext(MOZ_GTK_TAB_TOP);
+    gtk_style_context_get_style(style, "has-tab-gap", &notebook_has_tab_gap,
+                                NULL);
+  } else {
+    notebook_has_tab_gap = true;
+  }
+
+  sCheckboxMetrics.initialized = false;
+  sRadioMetrics.initialized = false;
+  sToolbarMetrics.initialized = false;
+  sToplevelWindowDecorationSize.initialized = false;
+  sPopupWindowDecorationSize.initialized = false;
+
+  /* This will destroy all of our widgets */
+  ResetWidgetCache();
+}
+
+gint moz_gtk_button_get_default_overflow(gint* border_top, gint* border_left,
+                                         gint* border_bottom,
+                                         gint* border_right) {
+  GtkBorder* default_outside_border;
+
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_BUTTON);
+  gtk_style_context_get_style(style, "default-outside-border",
+                              &default_outside_border, NULL);
+
+  if (default_outside_border) {
+    *border_top = default_outside_border->top;
+    *border_left = default_outside_border->left;
+    *border_bottom = default_outside_border->bottom;
+    *border_right = default_outside_border->right;
+    gtk_border_free(default_outside_border);
+  } else {
+    *border_top = *border_left = *border_bottom = *border_right = 0;
+  }
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_button_get_default_border(gint* border_top,
+                                              gint* border_left,
+                                              gint* border_bottom,
+                                              gint* border_right) {
+  GtkBorder* default_border;
+
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_BUTTON);
+  gtk_style_context_get_style(style, "default-border", &default_border, NULL);
+
+  if (default_border) {
+    *border_top = default_border->top;
+    *border_left = default_border->left;
+    *border_bottom = default_border->bottom;
+    *border_right = default_border->right;
+    gtk_border_free(default_border);
+  } else {
+    /* see gtkbutton.c */
+    *border_top = *border_left = *border_bottom = *border_right = 1;
+  }
+  return MOZ_GTK_SUCCESS;
+}
+
+gint moz_gtk_splitter_get_metrics(gint orientation, gint* size) {
+  GtkStyleContext* style;
+  if (orientation == GTK_ORIENTATION_HORIZONTAL) {
+    style = GetStyleContext(MOZ_GTK_SPLITTER_HORIZONTAL);
+  } else {
+    style = GetStyleContext(MOZ_GTK_SPLITTER_VERTICAL);
+  }
+  gtk_style_context_get_style(style, "handle_size", size, NULL);
+  return MOZ_GTK_SUCCESS;
+}
+
+static void CalculateToolbarButtonMetrics(WidgetNodeType aAppearance,
+                                          ToolbarButtonGTKMetrics* aMetrics) {
+  gint iconWidth, iconHeight;
+  if (!gtk_icon_size_lookup(GTK_ICON_SIZE_MENU, &iconWidth, &iconHeight)) {
+    NS_WARNING("Failed to get Gtk+ icon size for titlebar button!");
+
+    // Use some reasonable fallback size
+    iconWidth = 16;
+    iconHeight = 16;
+  }
+
+  GtkStyleContext* style = GetStyleContext(aAppearance);
+  gint width = 0, height = 0;
+  if (!gtk_check_version(3, 20, 0)) {
+    gtk_style_context_get(style, gtk_style_context_get_state(style),
+                          "min-width", &width, "min-height", &height, NULL);
+  }
+
+  // Cover cases when min-width/min-height is not set, it's invalid
+  // or we're running on Gtk+ < 3.20.
+  if (width < iconWidth) width = iconWidth;
+  if (height < iconHeight) height = iconHeight;
+
+  gint left = 0, top = 0, right = 0, bottom = 0;
+  moz_gtk_add_border_padding(style, &left, &top, &right, &bottom);
+
+  // Button size is calculated as min-width/height + border/padding.
+  width += left + right;
+  height += top + bottom;
+
+  // Place icon at button center.
+  aMetrics->iconXPosition = (width - iconWidth) / 2;
+  aMetrics->iconYPosition = (height - iconHeight) / 2;
+
+  aMetrics->minSizeWithBorderMargin.width = width;
+  aMetrics->minSizeWithBorderMargin.height = height;
+}
+
+// We support LTR layout only here for now.
+static void CalculateToolbarButtonSpacing(WidgetNodeType aAppearance,
+                                          ToolbarButtonGTKMetrics* aMetrics) {
+  GtkStyleContext* style = GetStyleContext(aAppearance);
+  gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
+                               &aMetrics->buttonMargin);
+
+  // Get titlebar spacing, a default one is 6 pixels (gtk/gtkheaderbar.c)
+  gint buttonSpacing = 6;
+  g_object_get(GetWidget(MOZ_GTK_HEADER_BAR), "spacing", &buttonSpacing,
+               nullptr);
+
+  // We apply spacing as a margin equally to both adjacent buttons.
+  buttonSpacing /= 2;
+
+  if (!aMetrics->firstButton) {
+    aMetrics->buttonMargin.left += buttonSpacing;
+  }
+  if (!aMetrics->lastButton) {
+    aMetrics->buttonMargin.right += buttonSpacing;
+  }
+
+  aMetrics->minSizeWithBorderMargin.width +=
+      aMetrics->buttonMargin.right + aMetrics->buttonMargin.left;
+  aMetrics->minSizeWithBorderMargin.height +=
+      aMetrics->buttonMargin.top + aMetrics->buttonMargin.bottom;
+}
+
+size_t GetGtkHeaderBarButtonLayout(Span<ButtonLayout> aButtonLayout,
+                                   bool* aReversedButtonsPlacement) {
+  gchar* decorationLayoutSetting = nullptr;
+  GtkSettings* settings = gtk_settings_get_default();
+  g_object_get(settings, "gtk-decoration-layout", &decorationLayoutSetting,
+               nullptr);
+  auto free = mozilla::MakeScopeExit([&] { g_free(decorationLayoutSetting); });
+
+  // Use a default layout
+  const gchar* decorationLayout = "menu:minimize,maximize,close";
+  if (decorationLayoutSetting) {
+    decorationLayout = decorationLayoutSetting;
+  }
+
+  // "minimize,maximize,close:" layout means buttons are on the opposite
+  // titlebar side. close button is always there.
+  if (aReversedButtonsPlacement) {
+    const char* closeButton = strstr(decorationLayout, "close");
+    const char* separator = strchr(decorationLayout, ':');
+    *aReversedButtonsPlacement =
+        closeButton && separator && closeButton < separator;
+  }
+
+  // We check what position a button string is stored in decorationLayout.
+  //
+  // decorationLayout gets its value from the GNOME preference:
+  // org.gnome.desktop.vm.preferences.button-layout via the
+  // gtk-decoration-layout property.
+  //
+  // Documentation of the gtk-decoration-layout property can be found here:
+  // https://developer.gnome.org/gtk3/stable/GtkSettings.html#GtkSettings--gtk-decoration-layout
+  if (aButtonLayout.IsEmpty()) {
+    return 0;
+  }
+
+  nsDependentCSubstring layout(decorationLayout, strlen(decorationLayout));
+
+  size_t activeButtons = 0;
+  for (const auto& part : layout.Split(':')) {
+    for (const auto& button : part.Split(',')) {
+      if (button.EqualsLiteral("close")) {
+        aButtonLayout[activeButtons++] = {MOZ_GTK_HEADER_BAR_BUTTON_CLOSE};
+      } else if (button.EqualsLiteral("minimize")) {
+        aButtonLayout[activeButtons++] = {MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE};
+      } else if (button.EqualsLiteral("maximize")) {
+        aButtonLayout[activeButtons++] = {MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE};
+      }
+      if (activeButtons == aButtonLayout.Length()) {
+        return activeButtons;
+      }
+    }
+  }
+  return activeButtons;
+}
+
+static void EnsureToolbarMetrics() {
+  if (sToolbarMetrics.initialized) {
+    return;
+  }
+  // Make sure we have clean cache after theme reset, etc.
+  memset(&sToolbarMetrics, 0, sizeof(sToolbarMetrics));
+
+  // Calculate titlebar button visibility and positions.
+  ButtonLayout aButtonLayout[TOOLBAR_BUTTONS];
+  size_t activeButtonNums =
+      GetGtkHeaderBarButtonLayout(Span(aButtonLayout), nullptr);
+
+  for (size_t i = 0; i < activeButtonNums; i++) {
+    int buttonIndex =
+        (aButtonLayout[i].mType - MOZ_GTK_HEADER_BAR_BUTTON_CLOSE);
+    ToolbarButtonGTKMetrics* metrics = sToolbarMetrics.button + buttonIndex;
+    metrics->visible = true;
+    // Mark first button
+    if (!i) {
+      metrics->firstButton = true;
+    }
+    // Mark last button.
+    if (i == (activeButtonNums - 1)) {
+      metrics->lastButton = true;
+    }
+
+    CalculateToolbarButtonMetrics(aButtonLayout[i].mType, metrics);
+    CalculateToolbarButtonSpacing(aButtonLayout[i].mType, metrics);
+  }
+
+  sToolbarMetrics.initialized = true;
+}
+
+const ToolbarButtonGTKMetrics* GetToolbarButtonMetrics(
+    WidgetNodeType aAppearance) {
+  EnsureToolbarMetrics();
+
+  int buttonIndex = (aAppearance - MOZ_GTK_HEADER_BAR_BUTTON_CLOSE);
+  NS_ASSERTION(buttonIndex >= 0 && buttonIndex <= TOOLBAR_BUTTONS,
+               "GetToolbarButtonMetrics(): Wrong titlebar button!");
+  return sToolbarMetrics.button + buttonIndex;
+}
+
+static gint moz_gtk_window_decoration_paint(cairo_t* cr,
+                                            const GdkRectangle* rect,
+                                            GtkWidgetState* state,
+                                            GtkTextDirection direction) {
+  if (mozilla::widget::GdkIsWaylandDisplay()) {
+    // Doesn't seem to be needed.
+    return MOZ_GTK_SUCCESS;
+  }
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  GtkStyleContext* windowStyle =
+      GetStyleContext(MOZ_GTK_HEADERBAR_WINDOW, state->image_scale);
+  const bool solidDecorations =
+      gtk_style_context_has_class(windowStyle, "solid-csd");
+  GtkStyleContext* decorationStyle =
+      GetStyleContext(solidDecorations ? MOZ_GTK_WINDOW_DECORATION_SOLID
+                                       : MOZ_GTK_WINDOW_DECORATION,
+                      state->image_scale, GTK_TEXT_DIR_LTR, state_flags);
+
+  gtk_render_background(decorationStyle, cr, rect->x, rect->y, rect->width,
+                        rect->height);
+  gtk_render_frame(decorationStyle, cr, rect->x, rect->y, rect->width,
+                   rect->height);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_button_paint(cairo_t* cr, const GdkRectangle* rect,
+                                 GtkWidgetState* state, GtkReliefStyle relief,
+                                 GtkWidget* widget,
+                                 GtkTextDirection direction) {
+  if (!widget) {
+    return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  GtkStyleContext* style = gtk_widget_get_style_context(widget);
+  gint x = rect->x, y = rect->y, width = rect->width, height = rect->height;
+
+  gtk_widget_set_direction(widget, direction);
+
+  gtk_style_context_save(style);
+  StyleContextSetScale(style, state->image_scale);
+  gtk_style_context_set_state(style, state_flags);
+
+  if (state->isDefault && relief == GTK_RELIEF_NORMAL && !state->focused &&
+      !(state_flags & GTK_STATE_FLAG_PRELIGHT)) {
+    /* handle default borders both outside and inside the button */
+    gint default_top, default_left, default_bottom, default_right;
+    moz_gtk_button_get_default_overflow(&default_top, &default_left,
+                                        &default_bottom, &default_right);
+    x -= default_left;
+    y -= default_top;
+    width += default_left + default_right;
+    height += default_top + default_bottom;
+    gtk_render_background(style, cr, x, y, width, height);
+    gtk_render_frame(style, cr, x, y, width, height);
+    moz_gtk_button_get_default_border(&default_top, &default_left,
+                                      &default_bottom, &default_right);
+    x += default_left;
+    y += default_top;
+    width -= (default_left + default_right);
+    height -= (default_top + default_bottom);
+  } else if (relief != GTK_RELIEF_NONE || state->depressed ||
+             (state_flags & GTK_STATE_FLAG_PRELIGHT)) {
+    /* the following line can trigger an assertion (Crux theme)
+       file ../../gdk/gdkwindow.c: line 1846 (gdk_window_clear_area):
+       assertion `GDK_IS_WINDOW (window)' failed */
+    gtk_render_background(style, cr, x, y, width, height);
+    gtk_render_frame(style, cr, x, y, width, height);
+  }
+
+  if (state->focused) {
+    GtkBorder border;
+    gtk_style_context_get_border(style, state_flags, &border);
+    x += border.left;
+    y += border.top;
+    width -= (border.left + border.right);
+    height -= (border.top + border.bottom);
+    gtk_render_focus(style, cr, x, y, width, height);
+  }
+  gtk_style_context_restore(style);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_header_bar_button_paint(cairo_t* cr,
+                                            const GdkRectangle* aRect,
+                                            GtkWidgetState* state,
+                                            GtkReliefStyle relief,
+                                            WidgetNodeType aIconWidgetType,
+                                            GtkTextDirection direction) {
+  GdkRectangle rect = *aRect;
+  // We need to inset our calculated margin because it also
+  // contains titlebar button spacing.
+  const ToolbarButtonGTKMetrics* metrics = GetToolbarButtonMetrics(
+      aIconWidgetType == MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE
+          ? MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE
+          : aIconWidgetType);
+  Inset(&rect, metrics->buttonMargin);
+
+  GtkWidget* buttonWidget = GetWidget(aIconWidgetType);
+  if (!buttonWidget) {
+    return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+  moz_gtk_button_paint(cr, &rect, state, relief, buttonWidget, direction);
+
+  GtkWidget* iconWidget =
+      gtk_bin_get_child(GTK_BIN(GetWidget(aIconWidgetType)));
+  if (!iconWidget) {
+    return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+  cairo_surface_t* surface =
+      GetWidgetIconSurface(iconWidget, state->image_scale);
+
+  if (surface) {
+    GtkStyleContext* style = gtk_widget_get_style_context(buttonWidget);
+    GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+
+    gtk_style_context_save(style);
+    StyleContextSetScale(style, state->image_scale);
+    gtk_style_context_set_state(style, state_flags);
+
+    /* This is available since Gtk+ 3.10 as well as GtkHeaderBar */
+    gtk_render_icon_surface(style, cr, surface, rect.x + metrics->iconXPosition,
+                            rect.y + metrics->iconYPosition);
+    gtk_style_context_restore(style);
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_toggle_paint(cairo_t* cr, GdkRectangle* rect,
+                                 GtkWidgetState* state, gboolean selected,
+                                 gboolean inconsistent, gboolean isradio,
+                                 GtkTextDirection direction) {
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  gint x, y, width, height;
+  GtkStyleContext* style;
+
+  // We need to call this before GetStyleContext, because otherwise we would
+  // reset state flags
+  const ToggleGTKMetrics* metrics =
+      GetToggleMetrics(isradio ? MOZ_GTK_RADIOBUTTON : MOZ_GTK_CHECKBUTTON);
+  // Clamp the rect and paint it center aligned in the rect.
+  x = rect->x;
+  y = rect->y;
+  width = rect->width;
+  height = rect->height;
+
+  if (rect->width < rect->height) {
+    y = rect->y + (rect->height - rect->width) / 2;
+    height = rect->width;
+  }
+
+  if (rect->height < rect->width) {
+    x = rect->x + (rect->width - rect->height) / 2;
+    width = rect->height;
+  }
+
+  if (selected)
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags | checkbox_check_state);
+
+  if (inconsistent)
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags | GTK_STATE_FLAG_INCONSISTENT);
+
+  style = GetStyleContext(isradio ? MOZ_GTK_RADIOBUTTON : MOZ_GTK_CHECKBUTTON,
+                          state->image_scale, direction, state_flags);
+
+  if (gtk_check_version(3, 20, 0) == nullptr) {
+    gtk_render_background(style, cr, x, y, width, height);
+    gtk_render_frame(style, cr, x, y, width, height);
+    // Indicator is inset by the toggle's padding and border.
+    gint indicator_x = x + metrics->borderAndPadding.left;
+    gint indicator_y = y + metrics->borderAndPadding.top;
+    gint indicator_width = metrics->minSizeWithBorder.width -
+                           metrics->borderAndPadding.left -
+                           metrics->borderAndPadding.right;
+    gint indicator_height = metrics->minSizeWithBorder.height -
+                            metrics->borderAndPadding.top -
+                            metrics->borderAndPadding.bottom;
+    if (isradio) {
+      gtk_render_option(style, cr, indicator_x, indicator_y, indicator_width,
+                        indicator_height);
+    } else {
+      gtk_render_check(style, cr, indicator_x, indicator_y, indicator_width,
+                       indicator_height);
+    }
+  } else {
+    if (isradio) {
+      gtk_render_option(style, cr, x, y, width, height);
+    } else {
+      gtk_render_check(style, cr, x, y, width, height);
+    }
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint calculate_button_inner_rect(GtkWidget* button,
+                                        const GdkRectangle* rect,
+                                        GdkRectangle* inner_rect,
+                                        GtkTextDirection direction) {
+  GtkStyleContext* style;
+  GtkBorder border;
+  GtkBorder padding = {0, 0, 0, 0};
+
+  style = gtk_widget_get_style_context(button);
+
+  /* This mirrors gtkbutton's child positioning */
+  gtk_style_context_get_border(style, gtk_style_context_get_state(style),
+                               &border);
+  gtk_style_context_get_padding(style, gtk_style_context_get_state(style),
+                                &padding);
+
+  inner_rect->x = rect->x + border.left + padding.left;
+  inner_rect->y = rect->y + padding.top + border.top;
+  inner_rect->width =
+      MAX(1, rect->width - padding.left - padding.right - border.left * 2);
+  inner_rect->height =
+      MAX(1, rect->height - padding.top - padding.bottom - border.top * 2);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint calculate_arrow_rect(GtkWidget* arrow, GdkRectangle* rect,
+                                 GdkRectangle* arrow_rect,
+                                 GtkTextDirection direction) {
+  /* defined in gtkarrow.c */
+  gfloat arrow_scaling = 0.7;
+  gfloat xalign, xpad;
+  gint extent;
+  gint mxpad, mypad;
+  gfloat mxalign, myalign;
+  GtkMisc* misc = GTK_MISC(arrow);
+
+  gtk_style_context_get_style(gtk_widget_get_style_context(arrow),
+                              "arrow_scaling", &arrow_scaling, NULL);
+
+  gtk_misc_get_padding(misc, &mxpad, &mypad);
+  extent = MIN((rect->width - mxpad * 2), (rect->height - mypad * 2)) *
+           arrow_scaling;
+
+  gtk_misc_get_alignment(misc, &mxalign, &myalign);
+
+  xalign = direction == GTK_TEXT_DIR_LTR ? mxalign : 1.0 - mxalign;
+  xpad = mxpad + (rect->width - extent) * xalign;
+
+  arrow_rect->x = direction == GTK_TEXT_DIR_LTR ? floor(rect->x + xpad)
+                                                : ceil(rect->x + xpad);
+  arrow_rect->y = floor(rect->y + mypad + ((rect->height - extent) * myalign));
+
+  arrow_rect->width = arrow_rect->height = extent;
+
+  return MOZ_GTK_SUCCESS;
+}
+
+/**
+ * Get minimum widget size as sum of margin, padding, border and
+ * min-width/min-height.
+ */
+static void moz_gtk_get_widget_min_size(GtkStyleContext* style, int* width,
+                                        int* height) {
+  GtkStateFlags state_flags = gtk_style_context_get_state(style);
+  gtk_style_context_get(style, state_flags, "min-height", height, "min-width",
+                        width, nullptr);
+
+  GtkBorder border, padding, margin;
+  gtk_style_context_get_border(style, state_flags, &border);
+  gtk_style_context_get_padding(style, state_flags, &padding);
+  gtk_style_context_get_margin(style, state_flags, &margin);
+
+  *width += border.left + border.right + margin.left + margin.right +
+            padding.left + padding.right;
+  *height += border.top + border.bottom + margin.top + margin.bottom +
+             padding.top + padding.bottom;
+}
+
+static void Inset(GdkRectangle* rect, const GtkBorder& aBorder) {
+  rect->x += aBorder.left;
+  rect->y += aBorder.top;
+  rect->width -= aBorder.left + aBorder.right;
+  rect->height -= aBorder.top + aBorder.bottom;
+}
+
+// Inset a rectangle by the margins specified in a style context.
+static void InsetByMargin(GdkRectangle* rect, GtkStyleContext* style) {
+  GtkBorder margin;
+  gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
+                               &margin);
+  Inset(rect, margin);
+}
+
+// Inset a rectangle by the border and padding specified in a style context.
+static void InsetByBorderPadding(GdkRectangle* rect, GtkStyleContext* style) {
+  GtkStateFlags state = gtk_style_context_get_state(style);
+  GtkBorder padding, border;
+
+  gtk_style_context_get_padding(style, state, &padding);
+  Inset(rect, padding);
+  gtk_style_context_get_border(style, state, &border);
+  Inset(rect, border);
+}
+
+static void moz_gtk_draw_styled_frame(GtkStyleContext* style, cairo_t* cr,
+                                      const GdkRectangle* aRect,
+                                      bool drawFocus) {
+  GdkRectangle rect = *aRect;
+
+  InsetByMargin(&rect, style);
+
+  gtk_render_background(style, cr, rect.x, rect.y, rect.width, rect.height);
+  gtk_render_frame(style, cr, rect.x, rect.y, rect.width, rect.height);
+  if (drawFocus) {
+    gtk_render_focus(style, cr, rect.x, rect.y, rect.width, rect.height);
+  }
+}
+
+static gint moz_gtk_inner_spin_paint(cairo_t* cr, GdkRectangle* rect,
+                                     GtkWidgetState* state,
+                                     GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_SPINBUTTON, state->image_scale, direction,
+                      GetStateFlagsFromGtkWidgetState(state));
+
+  gtk_render_background(style, cr, rect->x, rect->y, rect->width, rect->height);
+  gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
+
+  /* hard code these values */
+  GdkRectangle arrow_rect;
+  arrow_rect.width = 6;
+  arrow_rect.height = 6;
+
+  // align spin to the left
+  arrow_rect.x = rect->x;
+
+  // up button
+  arrow_rect.y = rect->y + (rect->height - arrow_rect.height) / 2 - 3;
+  gtk_render_arrow(style, cr, ARROW_UP, arrow_rect.x, arrow_rect.y,
+                   arrow_rect.width);
+
+  // down button
+  arrow_rect.y = rect->y + (rect->height - arrow_rect.height) / 2 + 3;
+  gtk_render_arrow(style, cr, ARROW_DOWN, arrow_rect.x, arrow_rect.y,
+                   arrow_rect.width);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_spin_paint(cairo_t* cr, GdkRectangle* rect,
+                               GtkWidgetState* state,
+                               GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_SPINBUTTON, state->image_scale, direction);
+  gtk_render_background(style, cr, rect->x, rect->y, rect->width, rect->height);
+  gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_spin_updown_paint(cairo_t* cr, GdkRectangle* rect,
+                                      gboolean isDown, GtkWidgetState* state,
+                                      GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_SPINBUTTON, state->image_scale, direction,
+                      GetStateFlagsFromGtkWidgetState(state));
+
+  gtk_render_background(style, cr, rect->x, rect->y, rect->width, rect->height);
+  gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
+
+  /* hard code these values */
+  GdkRectangle arrow_rect;
+  arrow_rect.width = 6;
+  arrow_rect.height = 6;
+  arrow_rect.x = rect->x + (rect->width - arrow_rect.width) / 2;
+  arrow_rect.y = rect->y + (rect->height - arrow_rect.height) / 2;
+  arrow_rect.y += isDown ? -1 : 1;
+
+  gtk_render_arrow(style, cr, isDown ? ARROW_DOWN : ARROW_UP, arrow_rect.x,
+                   arrow_rect.y, arrow_rect.width);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+/* See gtk_range_draw() for reference.
+ */
+static gint moz_gtk_scale_paint(cairo_t* cr, GdkRectangle* rect,
+                                GtkWidgetState* state, GtkOrientation flags,
+                                GtkTextDirection direction) {
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  gint x, y, width, height, min_width, min_height;
+  GtkStyleContext* style;
+  GtkBorder margin;
+
+  moz_gtk_get_scale_metrics(flags, &min_width, &min_height);
+
+  WidgetNodeType widget = (flags == GTK_ORIENTATION_HORIZONTAL)
+                              ? MOZ_GTK_SCALE_TROUGH_HORIZONTAL
+                              : MOZ_GTK_SCALE_TROUGH_VERTICAL;
+  style = GetStyleContext(widget, state->image_scale, direction, state_flags);
+  gtk_style_context_get_margin(style, state_flags, &margin);
+
+  // Clamp the dimension perpendicular to the direction that the slider crosses
+  // to the minimum size.
+  if (flags == GTK_ORIENTATION_HORIZONTAL) {
+    width = rect->width - (margin.left + margin.right);
+    height = min_height - (margin.top + margin.bottom);
+    x = rect->x + margin.left;
+    y = rect->y + (rect->height - height) / 2;
+  } else {
+    width = min_width - (margin.left + margin.right);
+    height = rect->height - (margin.top + margin.bottom);
+    x = rect->x + (rect->width - width) / 2;
+    y = rect->y + margin.top;
+  }
+
+  gtk_render_background(style, cr, x, y, width, height);
+  gtk_render_frame(style, cr, x, y, width, height);
+
+  if (state->focused)
+    gtk_render_focus(style, cr, rect->x, rect->y, rect->width, rect->height);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_scale_thumb_paint(cairo_t* cr, GdkRectangle* rect,
+                                      GtkWidgetState* state,
+                                      GtkOrientation flags,
+                                      GtkTextDirection direction) {
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  GtkStyleContext* style;
+  gint thumb_width, thumb_height, x, y;
+
+  /* determine the thumb size, and position the thumb in the center in the
+   * opposite axis
+   */
+  if (flags == GTK_ORIENTATION_HORIZONTAL) {
+    moz_gtk_get_scalethumb_metrics(GTK_ORIENTATION_HORIZONTAL, &thumb_width,
+                                   &thumb_height);
+    x = rect->x;
+    y = rect->y + (rect->height - thumb_height) / 2;
+  } else {
+    moz_gtk_get_scalethumb_metrics(GTK_ORIENTATION_VERTICAL, &thumb_height,
+                                   &thumb_width);
+    x = rect->x + (rect->width - thumb_width) / 2;
+    y = rect->y;
+  }
+
+  WidgetNodeType widget = (flags == GTK_ORIENTATION_HORIZONTAL)
+                              ? MOZ_GTK_SCALE_THUMB_HORIZONTAL
+                              : MOZ_GTK_SCALE_THUMB_VERTICAL;
+  style = GetStyleContext(widget, state->image_scale, direction, state_flags);
+  gtk_render_slider(style, cr, x, y, thumb_width, thumb_height, flags);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_hpaned_paint(cairo_t* cr, GdkRectangle* rect,
+                                 GtkWidgetState* state) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_SPLITTER_SEPARATOR_HORIZONTAL, state->image_scale,
+                      GTK_TEXT_DIR_LTR, GetStateFlagsFromGtkWidgetState(state));
+  gtk_render_handle(style, cr, rect->x, rect->y, rect->width, rect->height);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_vpaned_paint(cairo_t* cr, GdkRectangle* rect,
+                                 GtkWidgetState* state) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_SPLITTER_SEPARATOR_VERTICAL, state->image_scale,
+                      GTK_TEXT_DIR_LTR, GetStateFlagsFromGtkWidgetState(state));
+  gtk_render_handle(style, cr, rect->x, rect->y, rect->width, rect->height);
+  return MOZ_GTK_SUCCESS;
+}
+
+// See gtk_entry_draw() for reference.
+static gint moz_gtk_entry_paint(cairo_t* cr, const GdkRectangle* aRect,
+                                GtkWidgetState* state, GtkStyleContext* style,
+                                WidgetNodeType widget) {
+  GdkRectangle rect = *aRect;
+  gtk_render_background(style, cr, rect.x, rect.y, rect.width, rect.height);
+
+  // Paint the border, except for 'menulist-textfield' that isn't focused:
+  if (widget != MOZ_GTK_DROPDOWN_ENTRY || state->focused) {
+    gtk_render_frame(style, cr, rect.x, rect.y, rect.width, rect.height);
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_text_view_paint(cairo_t* cr, GdkRectangle* aRect,
+                                    GtkWidgetState* state,
+                                    GtkTextDirection direction) {
+  // GtkTextView and GtkScrolledWindow do not set active and prelight flags.
+  // The use of focus with MOZ_GTK_SCROLLED_WINDOW here is questionable
+  // because a parent widget will not have focus when its child GtkTextView
+  // has focus, but perhaps this may help identify a focused textarea with
+  // some themes as GtkTextView backgrounds do not typically render
+  // differently with focus.
+  GtkStateFlags state_flags = state->disabled  ? GTK_STATE_FLAG_INSENSITIVE
+                              : state->focused ? GTK_STATE_FLAG_FOCUSED
+                                               : GTK_STATE_FLAG_NORMAL;
+
+  GtkStyleContext* style_frame = GetStyleContext(
+      MOZ_GTK_SCROLLED_WINDOW, state->image_scale, direction, state_flags);
+  gtk_render_frame(style_frame, cr, aRect->x, aRect->y, aRect->width,
+                   aRect->height);
+
+  GdkRectangle rect = *aRect;
+  InsetByBorderPadding(&rect, style_frame);
+
+  GtkStyleContext* style = GetStyleContext(
+      MOZ_GTK_TEXT_VIEW, state->image_scale, direction, state_flags);
+  gtk_render_background(style, cr, rect.x, rect.y, rect.width, rect.height);
+  // There is a separate "text" window, which usually provides the
+  // background behind the text.  However, this is transparent in Ambiance
+  // for GTK 3.20, in which case the MOZ_GTK_TEXT_VIEW background is
+  // visible.
+  style = GetStyleContext(MOZ_GTK_TEXT_VIEW_TEXT, state->image_scale, direction,
+                          state_flags);
+  gtk_render_background(style, cr, rect.x, rect.y, rect.width, rect.height);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_treeview_paint(cairo_t* cr, GdkRectangle* rect,
+                                   GtkWidgetState* state,
+                                   GtkTextDirection direction) {
+  gint xthickness, ythickness;
+  GtkStyleContext* style;
+  GtkStyleContext* style_tree;
+  GtkStateFlags state_flags;
+  GtkBorder border;
+
+  /* only handle disabled and normal states, otherwise the whole background
+   * area will be painted differently with other states */
+  state_flags =
+      state->disabled ? GTK_STATE_FLAG_INSENSITIVE : GTK_STATE_FLAG_NORMAL;
+
+  style =
+      GetStyleContext(MOZ_GTK_SCROLLED_WINDOW, state->image_scale, direction);
+  gtk_style_context_get_border(style, state_flags, &border);
+  xthickness = border.left;
+  ythickness = border.top;
+
+  style_tree =
+      GetStyleContext(MOZ_GTK_TREEVIEW_VIEW, state->image_scale, direction);
+  gtk_render_background(style_tree, cr, rect->x + xthickness,
+                        rect->y + ythickness, rect->width - 2 * xthickness,
+                        rect->height - 2 * ythickness);
+
+  style =
+      GetStyleContext(MOZ_GTK_SCROLLED_WINDOW, state->image_scale, direction);
+  gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_tree_header_cell_paint(cairo_t* cr,
+                                           const GdkRectangle* aRect,
+                                           GtkWidgetState* state,
+                                           gboolean isSorted,
+                                           GtkTextDirection direction) {
+  moz_gtk_button_paint(cr, aRect, state, GTK_RELIEF_NORMAL,
+                       GetWidget(MOZ_GTK_TREE_HEADER_CELL), direction);
+  return MOZ_GTK_SUCCESS;
+}
+
+/* See gtk_expander_paint() for reference.
+ */
+static gint moz_gtk_treeview_expander_paint(cairo_t* cr, GdkRectangle* rect,
+                                            GtkWidgetState* state,
+                                            GtkExpanderStyle expander_state,
+                                            GtkTextDirection direction) {
+  /* Because the frame we get is of the entire treeview, we can't get the
+   * precise event state of one expander, thus rendering hover and active
+   * feedback useless. */
+  GtkStateFlags state_flags =
+      state->disabled ? GTK_STATE_FLAG_INSENSITIVE : GTK_STATE_FLAG_NORMAL;
+
+  if (state->inHover)
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags | GTK_STATE_FLAG_PRELIGHT);
+  if (state->selected)
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags | GTK_STATE_FLAG_SELECTED);
+
+  /* GTK_STATE_FLAG_ACTIVE controls expanded/colapsed state rendering
+   * in gtk_render_expander()
+   */
+  if (expander_state == GTK_EXPANDER_EXPANDED)
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags | checkbox_check_state);
+  else
+    state_flags =
+        static_cast<GtkStateFlags>(state_flags & ~(checkbox_check_state));
+
+  GtkStyleContext* style = GetStyleContext(
+      MOZ_GTK_TREEVIEW_EXPANDER, state->image_scale, direction, state_flags);
+  gtk_render_expander(style, cr, rect->x, rect->y, rect->width, rect->height);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+/* See gtk_separator_draw() for reference.
+ */
+static gint moz_gtk_combo_box_paint(cairo_t* cr, const GdkRectangle* aRect,
+                                    GtkWidgetState* state,
+                                    GtkTextDirection direction) {
+  GdkRectangle arrow_rect, real_arrow_rect;
+  gint separator_width;
+  gboolean wide_separators;
+  GtkStyleContext* style;
+  GtkRequisition arrow_req;
+
+  GtkWidget* comboBoxButton = GetWidget(MOZ_GTK_COMBOBOX_BUTTON);
+  GtkWidget* comboBoxArrow = GetWidget(MOZ_GTK_COMBOBOX_ARROW);
+  if (!comboBoxButton || !comboBoxArrow) {
+    return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+
+  /* Also sets the direction on gComboBoxButtonWidget, which is then
+   * inherited by the separator and arrow */
+  moz_gtk_button_paint(cr, aRect, state, GTK_RELIEF_NORMAL, comboBoxButton,
+                       direction);
+
+  calculate_button_inner_rect(comboBoxButton, aRect, &arrow_rect, direction);
+  /* Now arrow_rect contains the inner rect ; we want to correct the width
+   * to what the arrow needs (see gtk_combo_box_size_allocate) */
+  gtk_widget_get_preferred_size(comboBoxArrow, NULL, &arrow_req);
+  moz_gtk_sanity_preferred_size(&arrow_req);
+
+  if (direction == GTK_TEXT_DIR_LTR)
+    arrow_rect.x += arrow_rect.width - arrow_req.width;
+  arrow_rect.width = arrow_req.width;
+
+  calculate_arrow_rect(comboBoxArrow, &arrow_rect, &real_arrow_rect, direction);
+
+  style = GetStyleContext(MOZ_GTK_COMBOBOX_ARROW, state->image_scale);
+  gtk_render_arrow(style, cr, ARROW_DOWN, real_arrow_rect.x, real_arrow_rect.y,
+                   real_arrow_rect.width);
+
+  /* If there is no separator in the theme, there's nothing left to do. */
+  GtkWidget* widget = GetWidget(MOZ_GTK_COMBOBOX_SEPARATOR);
+  if (!widget) {
+    return MOZ_GTK_SUCCESS;
+  }
+  style = gtk_widget_get_style_context(widget);
+  StyleContextSetScale(style, state->image_scale);
+  gtk_style_context_get_style(style, "wide-separators", &wide_separators,
+                              "separator-width", &separator_width, NULL);
+
+  if (wide_separators) {
+    if (direction == GTK_TEXT_DIR_LTR)
+      arrow_rect.x -= separator_width;
+    else
+      arrow_rect.x += arrow_rect.width;
+
+    gtk_render_frame(style, cr, arrow_rect.x, arrow_rect.y, separator_width,
+                     arrow_rect.height);
+  } else {
+    if (direction == GTK_TEXT_DIR_LTR) {
+      GtkBorder padding;
+      GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+      gtk_style_context_get_padding(style, state_flags, &padding);
+      arrow_rect.x -= padding.left;
+    } else
+      arrow_rect.x += arrow_rect.width;
+
+    gtk_render_line(style, cr, arrow_rect.x, arrow_rect.y, arrow_rect.x,
+                    arrow_rect.y + arrow_rect.height);
+  }
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_arrow_paint(cairo_t* cr, GdkRectangle* rect,
+                                GtkWidgetState* state, GtkArrowType arrow_type,
+                                GtkTextDirection direction) {
+  GdkRectangle arrow_rect;
+  gdouble arrow_angle;
+
+  if (direction == GTK_TEXT_DIR_RTL) {
+    if (arrow_type == GTK_ARROW_LEFT) {
+      arrow_type = GTK_ARROW_RIGHT;
+    } else if (arrow_type == GTK_ARROW_RIGHT) {
+      arrow_type = GTK_ARROW_LEFT;
+    }
+  }
+  switch (arrow_type) {
+    case GTK_ARROW_LEFT:
+      arrow_angle = ARROW_LEFT;
+      break;
+    case GTK_ARROW_RIGHT:
+      arrow_angle = ARROW_RIGHT;
+      break;
+    case GTK_ARROW_DOWN:
+      arrow_angle = ARROW_DOWN;
+      break;
+    default:
+      arrow_angle = ARROW_UP;
+      break;
+  }
+  if (arrow_type == GTK_ARROW_NONE) return MOZ_GTK_SUCCESS;
+
+  GtkWidget* widget = GetWidget(MOZ_GTK_BUTTON_ARROW);
+  if (!widget) {
+    return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+  calculate_arrow_rect(widget, rect, &arrow_rect, direction);
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  GtkStyleContext* style = GetStyleContext(
+      MOZ_GTK_BUTTON_ARROW, state->image_scale, direction, state_flags);
+  gtk_render_arrow(style, cr, arrow_angle, arrow_rect.x, arrow_rect.y,
+                   arrow_rect.width);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_tooltip_paint(cairo_t* cr, const GdkRectangle* aRect,
+                                  GtkWidgetState* state,
+                                  GtkTextDirection direction) {
+  // Tooltip widget is made in GTK3 as following tree:
+  // Tooltip window
+  //   Horizontal Box
+  //     Icon (not supported by Firefox)
+  //     Label
+  // Each element can be fully styled by CSS of GTK theme.
+  // We have to draw all elements with appropriate offset and right dimensions.
+
+  // Tooltip drawing
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_TOOLTIP, state->image_scale, direction);
+  GdkRectangle rect = *aRect;
+  gtk_render_background(style, cr, rect.x, rect.y, rect.width, rect.height);
+  gtk_render_frame(style, cr, rect.x, rect.y, rect.width, rect.height);
+
+  // Horizontal Box drawing
+  //
+  // The box element has hard-coded 6px margin-* GtkWidget properties, which
+  // are added between the window dimensions and the CSS margin box of the
+  // horizontal box.  The frame of the tooltip window is drawn in the
+  // 6px margin.
+  // For drawing Horizontal Box we have to inset drawing area by that 6px
+  // plus its CSS margin.
+  GtkStyleContext* boxStyle =
+      GetStyleContext(MOZ_GTK_TOOLTIP_BOX, state->image_scale, direction);
+
+  rect.x += 6;
+  rect.y += 6;
+  rect.width -= 12;
+  rect.height -= 12;
+
+  InsetByMargin(&rect, boxStyle);
+  gtk_render_background(boxStyle, cr, rect.x, rect.y, rect.width, rect.height);
+  gtk_render_frame(boxStyle, cr, rect.x, rect.y, rect.width, rect.height);
+
+  // Label drawing
+  InsetByBorderPadding(&rect, boxStyle);
+
+  GtkStyleContext* labelStyle =
+      GetStyleContext(MOZ_GTK_TOOLTIP_BOX_LABEL, state->image_scale, direction);
+  moz_gtk_draw_styled_frame(labelStyle, cr, &rect, false);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_resizer_paint(cairo_t* cr, GdkRectangle* rect,
+                                  GtkWidgetState* state,
+                                  GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_RESIZER, state->image_scale, GTK_TEXT_DIR_LTR,
+                      GetStateFlagsFromGtkWidgetState(state));
+
+  // Workaround unico not respecting the text direction for resizers.
+  // See bug 1174248.
+  cairo_save(cr);
+  if (direction == GTK_TEXT_DIR_RTL) {
+    cairo_matrix_t mat;
+    cairo_matrix_init_translate(&mat, 2 * rect->x + rect->width, 0);
+    cairo_matrix_scale(&mat, -1, 1);
+    cairo_transform(cr, &mat);
+  }
+
+  gtk_render_handle(style, cr, rect->x, rect->y, rect->width, rect->height);
+  cairo_restore(cr);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_frame_paint(cairo_t* cr, GdkRectangle* rect,
+                                GtkWidgetState* state,
+                                GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_FRAME, state->image_scale, direction);
+  gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_progressbar_paint(cairo_t* cr, GdkRectangle* rect,
+                                      GtkWidgetState* state,
+                                      GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_PROGRESS_TROUGH, state->image_scale, direction);
+  gtk_render_background(style, cr, rect->x, rect->y, rect->width, rect->height);
+  gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_progress_chunk_paint(cairo_t* cr, GdkRectangle* rect,
+                                         GtkWidgetState* state,
+                                         GtkTextDirection direction,
+                                         WidgetNodeType widget) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_PROGRESS_CHUNK, state->image_scale, direction);
+
+  if (widget == MOZ_GTK_PROGRESS_CHUNK_INDETERMINATE ||
+      widget == MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE) {
+    /**
+     * The bar's size and the bar speed are set depending of the progress'
+     * size. These could also be constant for all progress bars easily.
+     */
+    gboolean vertical =
+        (widget == MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE);
+
+    /* The size of the dimension we are going to use for the animation. */
+    const gint progressSize = vertical ? rect->height : rect->width;
+
+    /* The bar is using a fifth of the element size, based on GtkProgressBar
+     * activity-blocks property. */
+    const gint barSize = MAX(1, progressSize / 5);
+
+    /* Represents the travel that has to be done for a complete cycle. */
+    const gint travel = 2 * (progressSize - barSize);
+
+    /* period equals to travel / pixelsPerMillisecond
+     * where pixelsPerMillisecond equals progressSize / 1000.0.
+     * This is equivalent to 1600. */
+    static const guint period = 1600;
+    const gint t = PR_IntervalToMilliseconds(PR_IntervalNow()) % period;
+    const gint dx = travel * t / period;
+
+    if (vertical) {
+      rect->y += (dx < travel / 2) ? dx : travel - dx;
+      rect->height = barSize;
+    } else {
+      rect->x += (dx < travel / 2) ? dx : travel - dx;
+      rect->width = barSize;
+    }
+  }
+
+  gtk_render_background(style, cr, rect->x, rect->y, rect->width, rect->height);
+  gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_get_tab_thickness(GtkStyleContext* style) {
+  if (!notebook_has_tab_gap)
+    return 0; /* tabs do not overdraw the tabpanel border with "no gap" style */
+
+  GtkBorder border;
+  gtk_style_context_get_border(style, gtk_style_context_get_state(style),
+                               &border);
+  if (border.top < 2) return 2; /* some themes don't set ythickness correctly */
+
+  return border.top;
+}
+
+gint moz_gtk_get_tab_thickness(WidgetNodeType aNodeType) {
+  GtkStyleContext* style = GetStyleContext(aNodeType);
+  int thickness = moz_gtk_get_tab_thickness(style);
+  return thickness;
+}
+
+/* actual small tabs */
+static gint moz_gtk_tab_paint(cairo_t* cr, GdkRectangle* rect,
+                              GtkWidgetState* state, GtkTabFlags flags,
+                              GtkTextDirection direction,
+                              WidgetNodeType widget) {
+  /* When the tab isn't selected, we just draw a notebook extension.
+   * When it is selected, we overwrite the adjacent border of the tabpanel
+   * touching the tab with a pierced border (called "the gap") to make the
+   * tab appear physically attached to the tabpanel; see details below. */
+
+  GtkStyleContext* style;
+  GdkRectangle tabRect;
+  GdkRectangle focusRect;
+  GdkRectangle backRect;
+  int initial_gap = 0;
+  bool isBottomTab = (widget == MOZ_GTK_TAB_BOTTOM);
+
+  style = GetStyleContext(widget, state->image_scale, direction,
+                          GetStateFlagsFromGtkTabFlags(flags));
+  tabRect = *rect;
+
+  if (flags & MOZ_GTK_TAB_FIRST) {
+    gtk_style_context_get_style(style, "initial-gap", &initial_gap, NULL);
+    tabRect.width -= initial_gap;
+
+    if (direction != GTK_TEXT_DIR_RTL) {
+      tabRect.x += initial_gap;
+    }
+  }
+
+  focusRect = backRect = tabRect;
+
+  if (notebook_has_tab_gap) {
+    if ((flags & MOZ_GTK_TAB_SELECTED) == 0) {
+      /* Only draw the tab */
+      gtk_render_extension(style, cr, tabRect.x, tabRect.y, tabRect.width,
+                           tabRect.height,
+                           isBottomTab ? GTK_POS_TOP : GTK_POS_BOTTOM);
+    } else {
+      /* Draw the tab and the gap
+       * We want the gap to be positioned exactly on the tabpanel top
+       * border; since tabbox.css may set a negative margin so that the tab
+       * frame rect already overlaps the tabpanel frame rect, we need to take
+       * that into account when drawing. To that effect, nsNativeThemeGTK
+       * passes us this negative margin (bmargin in the graphic below) in the
+       * lowest bits of |flags|.  We use it to set gap_voffset, the distance
+       * between the top of the gap and the bottom of the tab (resp. the
+       * bottom of the gap and the top of the tab when we draw a bottom tab),
+       * while ensuring that the gap always touches the border of the tab,
+       * i.e. 0 <= gap_voffset <= gap_height, to avoid surprinsing results
+       * with big negative or positive margins.
+       * Here is a graphical explanation in the case of top tabs:
+       *             ___________________________
+       *            /                           \
+       *           |            T A B            |
+       * ----------|. . . . . . . . . . . . . . .|----- top of tabpanel
+       *           :    ^       bmargin          :  ^
+       *           :    | (-negative margin,     :  |
+       *  bottom   :    v  passed in flags)      :  |       gap_height
+       *    of  -> :.............................:  |    (the size of the
+       * the tab   .       part of the gap       .  |  tabpanel top border)
+       *           .      outside of the tab     .  v
+       * ----------------------------------------------
+       *
+       * To draw the gap, we use gtk_render_frame_gap(), see comment in
+       * moz_gtk_tabpanels_paint(). This gap is made 3 * gap_height tall,
+       * which should suffice to ensure that the only visible border is the
+       * pierced one.  If the tab is in the middle, we make the box_gap begin
+       * a bit to the left of the tab and end a bit to the right, adjusting
+       * the gap position so it still is under the tab, because we want the
+       * rendering of a gap in the middle of a tabpanel.  This is the role of
+       * the gints gap_{l,r}_offset. On the contrary, if the tab is the
+       * first, we align the start border of the box_gap with the start
+       * border of the tab (left if LTR, right if RTL), by setting the
+       * appropriate offset to 0.*/
+      gint gap_loffset, gap_roffset, gap_voffset, gap_height;
+
+      /* Get height needed by the gap */
+      gap_height = moz_gtk_get_tab_thickness(style);
+
+      /* Extract gap_voffset from the first bits of flags */
+      gap_voffset = flags & MOZ_GTK_TAB_MARGIN_MASK;
+      if (gap_voffset > gap_height) gap_voffset = gap_height;
+
+      /* Set gap_{l,r}_offset to appropriate values */
+      gap_loffset = gap_roffset = 20; /* should be enough */
+      if (flags & MOZ_GTK_TAB_FIRST) {
+        if (direction == GTK_TEXT_DIR_RTL)
+          gap_roffset = initial_gap;
+        else
+          gap_loffset = initial_gap;
+      }
+
+      GtkStyleContext* panelStyle =
+          GetStyleContext(MOZ_GTK_TABPANELS, state->image_scale, direction);
+
+      if (isBottomTab) {
+        /* Draw the tab on bottom */
+        focusRect.y += gap_voffset;
+        focusRect.height -= gap_voffset;
+
+        gtk_render_extension(style, cr, tabRect.x, tabRect.y + gap_voffset,
+                             tabRect.width, tabRect.height - gap_voffset,
+                             GTK_POS_TOP);
+
+        backRect.y += (gap_voffset - gap_height);
+        backRect.height = gap_height;
+
+        /* Draw the gap; erase with background color before painting in
+         * case theme does not */
+        gtk_render_background(panelStyle, cr, backRect.x, backRect.y,
+                              backRect.width, backRect.height);
+        cairo_save(cr);
+        cairo_rectangle(cr, backRect.x, backRect.y, backRect.width,
+                        backRect.height);
+        cairo_clip(cr);
+
+        gtk_render_frame_gap(panelStyle, cr, tabRect.x - gap_loffset,
+                             tabRect.y + gap_voffset - 3 * gap_height,
+                             tabRect.width + gap_loffset + gap_roffset,
+                             3 * gap_height, GTK_POS_BOTTOM, gap_loffset,
+                             gap_loffset + tabRect.width);
+        cairo_restore(cr);
+      } else {
+        /* Draw the tab on top */
+        focusRect.height -= gap_voffset;
+        gtk_render_extension(style, cr, tabRect.x, tabRect.y, tabRect.width,
+                             tabRect.height - gap_voffset, GTK_POS_BOTTOM);
+
+        backRect.y += (tabRect.height - gap_voffset);
+        backRect.height = gap_height;
+
+        /* Draw the gap; erase with background color before painting in
+         * case theme does not */
+        gtk_render_background(panelStyle, cr, backRect.x, backRect.y,
+                              backRect.width, backRect.height);
+
+        cairo_save(cr);
+        cairo_rectangle(cr, backRect.x, backRect.y, backRect.width,
+                        backRect.height);
+        cairo_clip(cr);
+
+        gtk_render_frame_gap(panelStyle, cr, tabRect.x - gap_loffset,
+                             tabRect.y + tabRect.height - gap_voffset,
+                             tabRect.width + gap_loffset + gap_roffset,
+                             3 * gap_height, GTK_POS_TOP, gap_loffset,
+                             gap_loffset + tabRect.width);
+        cairo_restore(cr);
+      }
+    }
+  } else {
+    gtk_render_background(style, cr, tabRect.x, tabRect.y, tabRect.width,
+                          tabRect.height);
+    gtk_render_frame(style, cr, tabRect.x, tabRect.y, tabRect.width,
+                     tabRect.height);
+  }
+
+  if (state->focused) {
+    /* Paint the focus ring */
+    GtkBorder padding;
+    gtk_style_context_get_padding(style, GetStateFlagsFromGtkWidgetState(state),
+                                  &padding);
+
+    focusRect.x += padding.left;
+    focusRect.width -= (padding.left + padding.right);
+    focusRect.y += padding.top;
+    focusRect.height -= (padding.top + padding.bottom);
+
+    gtk_render_focus(style, cr, focusRect.x, focusRect.y, focusRect.width,
+                     focusRect.height);
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+/* tab area*/
+static gint moz_gtk_tabpanels_paint(cairo_t* cr, GdkRectangle* rect,
+                                    GtkWidgetState* state,
+                                    GtkTextDirection direction) {
+  GtkStyleContext* style =
+      GetStyleContext(MOZ_GTK_TABPANELS, state->image_scale, direction);
+  gtk_render_background(style, cr, rect->x, rect->y, rect->width, rect->height);
+  /*
+   * The gap size is not needed in moz_gtk_tabpanels_paint because
+   * the gap will be painted with the foreground tab in moz_gtk_tab_paint.
+   *
+   * However, if moz_gtk_tabpanels_paint just uses gtk_render_frame(),
+   * the theme will think that there are no tabs and may draw something
+   * different.Hence the trick of using two clip regions, and drawing the
+   * gap outside each clip region, to get the correct frame for
+   * a tabpanel with tabs.
+   */
+  /* left side */
+  cairo_save(cr);
+  cairo_rectangle(cr, rect->x, rect->y, rect->x + rect->width / 2,
+                  rect->y + rect->height);
+  cairo_clip(cr);
+  gtk_render_frame_gap(style, cr, rect->x, rect->y, rect->width, rect->height,
+                       GTK_POS_TOP, rect->width - 1, rect->width);
+  cairo_restore(cr);
+
+  /* right side */
+  cairo_save(cr);
+  cairo_rectangle(cr, rect->x + rect->width / 2, rect->y, rect->x + rect->width,
+                  rect->y + rect->height);
+  cairo_clip(cr);
+  gtk_render_frame_gap(style, cr, rect->x, rect->y, rect->width, rect->height,
+                       GTK_POS_TOP, 0, 1);
+  cairo_restore(cr);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_tab_scroll_arrow_paint(cairo_t* cr, GdkRectangle* rect,
+                                           GtkWidgetState* state,
+                                           GtkArrowType arrow_type,
+                                           GtkTextDirection direction) {
+  GtkStyleContext* style;
+  gdouble arrow_angle;
+  gint arrow_size = MIN(rect->width, rect->height);
+  gint x = rect->x + (rect->width - arrow_size) / 2;
+  gint y = rect->y + (rect->height - arrow_size) / 2;
+
+  if (direction == GTK_TEXT_DIR_RTL) {
+    arrow_type =
+        (arrow_type == GTK_ARROW_LEFT) ? GTK_ARROW_RIGHT : GTK_ARROW_LEFT;
+  }
+  switch (arrow_type) {
+    case GTK_ARROW_LEFT:
+      arrow_angle = ARROW_LEFT;
+      break;
+    case GTK_ARROW_RIGHT:
+      arrow_angle = ARROW_RIGHT;
+      break;
+    case GTK_ARROW_DOWN:
+      arrow_angle = ARROW_DOWN;
+      break;
+    default:
+      arrow_angle = ARROW_UP;
+      break;
+  }
+  if (arrow_type != GTK_ARROW_NONE) {
+    style = GetStyleContext(MOZ_GTK_TAB_SCROLLARROW, state->image_scale,
+                            direction, GetStateFlagsFromGtkWidgetState(state));
+    gtk_render_arrow(style, cr, arrow_angle, x, y, arrow_size);
+  }
+  return MOZ_GTK_SUCCESS;
+}
+
+static gint moz_gtk_header_bar_paint(WidgetNodeType widgetType, cairo_t* cr,
+                                     GdkRectangle* rect,
+                                     GtkWidgetState* state) {
+  GtkStateFlags state_flags = GetStateFlagsFromGtkWidgetState(state);
+  GtkStyleContext* style = GetStyleContext(widgetType, state->image_scale,
+                                           GTK_TEXT_DIR_NONE, state_flags);
+
+  // Some themes like Elementary's style the container of the headerbar rather
+  // than the header bar itself.
+  if (HeaderBarShouldDrawContainer(widgetType)) {
+    auto containerType = widgetType == MOZ_GTK_HEADER_BAR
+                             ? MOZ_GTK_HEADERBAR_FIXED
+                             : MOZ_GTK_HEADERBAR_FIXED_MAXIMIZED;
+    style = GetStyleContext(containerType, state->image_scale,
+                            GTK_TEXT_DIR_NONE, state_flags);
+  }
+
+  gtk_render_background(style, cr, rect->x, rect->y, rect->width, rect->height);
+  gtk_render_frame(style, cr, rect->x, rect->y, rect->width, rect->height);
+
+  return MOZ_GTK_SUCCESS;
+}
+
+gint moz_gtk_get_widget_border(WidgetNodeType widget, gint* left, gint* top,
+                               gint* right, gint* bottom,
+                               // NOTE: callers depend on direction being used
+                               // only for MOZ_GTK_DROPDOWN widgets.
+                               GtkTextDirection direction) {
+  GtkWidget* w;
+  GtkStyleContext* style;
+  *left = *top = *right = *bottom = 0;
+
+  switch (widget) {
+    case MOZ_GTK_BUTTON:
+    case MOZ_GTK_TOOLBAR_BUTTON: {
+      style = GetStyleContext(MOZ_GTK_BUTTON);
+
+      *left = *top = *right = *bottom = gtk_container_get_border_width(
+          GTK_CONTAINER(GetWidget(MOZ_GTK_BUTTON)));
+
+      if (widget == MOZ_GTK_TOOLBAR_BUTTON) {
+        gtk_style_context_save(style);
+        gtk_style_context_add_class(style, "image-button");
+      }
+
+      moz_gtk_add_style_padding(style, left, top, right, bottom);
+
+      if (widget == MOZ_GTK_TOOLBAR_BUTTON) gtk_style_context_restore(style);
+
+      moz_gtk_add_style_border(style, left, top, right, bottom);
+
+      return MOZ_GTK_SUCCESS;
+    }
+    case MOZ_GTK_ENTRY:
+    case MOZ_GTK_DROPDOWN_ENTRY: {
+      style = GetStyleContext(widget);
+
+      // XXX: Subtract 1 pixel from the padding to account for the default
+      // padding in forms.css. See bug 1187385.
+      *left = *top = *right = *bottom = -1;
+      moz_gtk_add_border_padding(style, left, top, right, bottom);
+
+      return MOZ_GTK_SUCCESS;
+    }
+    case MOZ_GTK_TEXT_VIEW:
+    case MOZ_GTK_TREEVIEW: {
+      style = GetStyleContext(MOZ_GTK_SCROLLED_WINDOW);
+      moz_gtk_add_style_border(style, left, top, right, bottom);
+      return MOZ_GTK_SUCCESS;
+    }
+    case MOZ_GTK_TREE_HEADER_CELL: {
+      /* A Tree Header in GTK is just a different styled button
+       * It must be placed in a TreeView for getting the correct style
+       * assigned.
+       * That is why the following code is the same as for MOZ_GTK_BUTTON.
+       * */
+      *left = *top = *right = *bottom = gtk_container_get_border_width(
+          GTK_CONTAINER(GetWidget(MOZ_GTK_TREE_HEADER_CELL)));
+      style = GetStyleContext(MOZ_GTK_TREE_HEADER_CELL);
+      moz_gtk_add_border_padding(style, left, top, right, bottom);
+      return MOZ_GTK_SUCCESS;
+    }
+    case MOZ_GTK_DROPDOWN: {
+      /* We need to account for the arrow on the dropdown, so text
+       * doesn't come too close to the arrow, or in some cases spill
+       * into the arrow. */
+      gboolean wide_separators;
+      gint separator_width;
+      GtkRequisition arrow_req;
+      GtkBorder border;
+
+      *left = *top = *right = *bottom = gtk_container_get_border_width(
+          GTK_CONTAINER(GetWidget(MOZ_GTK_COMBOBOX_BUTTON)));
+      style = GetStyleContext(MOZ_GTK_COMBOBOX_BUTTON);
+      moz_gtk_add_border_padding(style, left, top, right, bottom);
+
+      /* If there is no separator, don't try to count its width. */
+      separator_width = 0;
+      GtkWidget* comboBoxSeparator = GetWidget(MOZ_GTK_COMBOBOX_SEPARATOR);
+      if (comboBoxSeparator) {
+        style = gtk_widget_get_style_context(comboBoxSeparator);
+        gtk_style_context_get_style(style, "wide-separators", &wide_separators,
+                                    "separator-width", &separator_width, NULL);
+
+        if (!wide_separators) {
+          gtk_style_context_get_border(
+              style, gtk_style_context_get_state(style), &border);
+          separator_width = border.left;
+        }
+      }
+
+      gtk_widget_get_preferred_size(GetWidget(MOZ_GTK_COMBOBOX_ARROW), NULL,
+                                    &arrow_req);
+      moz_gtk_sanity_preferred_size(&arrow_req);
+
+      if (direction == GTK_TEXT_DIR_RTL)
+        *left += separator_width + arrow_req.width;
+      else
+        *right += separator_width + arrow_req.width;
+
+      return MOZ_GTK_SUCCESS;
+    }
+    case MOZ_GTK_TABPANELS:
+      w = GetWidget(MOZ_GTK_TABPANELS);
+      break;
+    case MOZ_GTK_PROGRESSBAR:
+      w = GetWidget(MOZ_GTK_PROGRESSBAR);
+      break;
+    case MOZ_GTK_SPINBUTTON_ENTRY:
+    case MOZ_GTK_SPINBUTTON_UP:
+    case MOZ_GTK_SPINBUTTON_DOWN:
+      w = GetWidget(MOZ_GTK_SPINBUTTON);
+      break;
+    case MOZ_GTK_SCALE_HORIZONTAL:
+    case MOZ_GTK_SCALE_VERTICAL:
+      w = GetWidget(widget);
+      break;
+    case MOZ_GTK_FRAME:
+      w = GetWidget(MOZ_GTK_FRAME);
+      break;
+    case MOZ_GTK_TOOLTIP: {
+      // In GTK 3 there are 6 pixels of additional margin around the box.
+      // See details there:
+      // https://github.com/GNOME/gtk/blob/5ea69a136bd7e4970b3a800390e20314665aaed2/gtk/ui/gtktooltipwindow.ui#L11
+      *left = *right = *top = *bottom = 6;
+
+      // We also need to add margin/padding/borders from Tooltip content.
+      // Tooltip contains horizontal box, where icon and label is put.
+      // We ignore icon as long as we don't have support for it.
+      GtkStyleContext* boxStyle = GetStyleContext(MOZ_GTK_TOOLTIP_BOX);
+      moz_gtk_add_margin_border_padding(boxStyle, left, top, right, bottom);
+
+      GtkStyleContext* labelStyle = GetStyleContext(MOZ_GTK_TOOLTIP_BOX_LABEL);
+      moz_gtk_add_margin_border_padding(labelStyle, left, top, right, bottom);
+
+      return MOZ_GTK_SUCCESS;
+    }
+    case MOZ_GTK_HEADER_BAR_BUTTON_BOX: {
+      style = GetStyleContext(MOZ_GTK_HEADER_BAR);
+      moz_gtk_add_border_padding(style, left, top, right, bottom);
+      *top = *bottom = 0;
+      bool leftButtonsPlacement = false;
+      GetGtkHeaderBarButtonLayout({}, &leftButtonsPlacement);
+      if (direction == GTK_TEXT_DIR_RTL) {
+        leftButtonsPlacement = !leftButtonsPlacement;
+      }
+      if (leftButtonsPlacement) {
+        *right = 0;
+      } else {
+        *left = 0;
+      }
+      return MOZ_GTK_SUCCESS;
+    }
+    /* These widgets have no borders, since they are not containers. */
+    case MOZ_GTK_SPLITTER_HORIZONTAL:
+    case MOZ_GTK_SPLITTER_VERTICAL:
+    case MOZ_GTK_CHECKBUTTON:
+    case MOZ_GTK_RADIOBUTTON:
+    case MOZ_GTK_SCALE_THUMB_HORIZONTAL:
+    case MOZ_GTK_SCALE_THUMB_VERTICAL:
+    case MOZ_GTK_PROGRESS_CHUNK:
+    case MOZ_GTK_PROGRESS_CHUNK_INDETERMINATE:
+    case MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE:
+    case MOZ_GTK_TREEVIEW_EXPANDER:
+    case MOZ_GTK_HEADER_BAR:
+    case MOZ_GTK_HEADER_BAR_MAXIMIZED:
+    case MOZ_GTK_HEADER_BAR_BUTTON_CLOSE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE:
+    /* These widgets have no borders.*/
+    case MOZ_GTK_INNER_SPIN_BUTTON:
+    case MOZ_GTK_SPINBUTTON:
+    case MOZ_GTK_WINDOW_DECORATION:
+    case MOZ_GTK_WINDOW_DECORATION_SOLID:
+    case MOZ_GTK_RESIZER:
+    case MOZ_GTK_TOOLBARBUTTON_ARROW:
+    case MOZ_GTK_TAB_SCROLLARROW:
+      return MOZ_GTK_SUCCESS;
+    default:
+      g_warning("Unsupported widget type: %d", widget);
+      return MOZ_GTK_UNKNOWN_WIDGET;
+  }
+  /* TODO - we're still missing some widget implementations */
+  if (w) {
+    moz_gtk_add_style_border(gtk_widget_get_style_context(w), left, top, right,
+                             bottom);
+  }
+  return MOZ_GTK_SUCCESS;
+}
+
+gint moz_gtk_get_tab_border(gint* left, gint* top, gint* right, gint* bottom,
+                            GtkTextDirection direction, GtkTabFlags flags,
+                            WidgetNodeType widget) {
+  GtkStyleContext* style = GetStyleContext(widget, 1, direction,
+                                           GetStateFlagsFromGtkTabFlags(flags));
+
+  *left = *top = *right = *bottom = 0;
+  moz_gtk_add_style_padding(style, left, top, right, bottom);
+
+  // Gtk >= 3.20 does not use those styles
+  if (gtk_check_version(3, 20, 0) != nullptr) {
+    int tab_curvature;
+
+    gtk_style_context_get_style(style, "tab-curvature", &tab_curvature, NULL);
+    *left += tab_curvature;
+    *right += tab_curvature;
+
+    if (flags & MOZ_GTK_TAB_FIRST) {
+      int initial_gap = 0;
+      gtk_style_context_get_style(style, "initial-gap", &initial_gap, NULL);
+      if (direction == GTK_TEXT_DIR_RTL)
+        *right += initial_gap;
+      else
+        *left += initial_gap;
+    }
+  } else {
+    GtkBorder margin;
+
+    gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
+                                 &margin);
+    *left += margin.left;
+    *right += margin.right;
+
+    if (flags & MOZ_GTK_TAB_FIRST) {
+      style = GetStyleContext(MOZ_GTK_NOTEBOOK_HEADER, direction);
+      gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
+                                   &margin);
+      *left += margin.left;
+      *right += margin.right;
+    }
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+gint moz_gtk_get_tab_scroll_arrow_size(gint* width, gint* height) {
+  gint arrow_size;
+
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_TABPANELS);
+  gtk_style_context_get_style(style, "scroll-arrow-hlength", &arrow_size, NULL);
+
+  *height = *width = arrow_size;
+
+  return MOZ_GTK_SUCCESS;
+}
+
+void moz_gtk_get_arrow_size(WidgetNodeType widgetType, gint* width,
+                            gint* height) {
+  GtkWidget* widget;
+  switch (widgetType) {
+    case MOZ_GTK_DROPDOWN:
+      widget = GetWidget(MOZ_GTK_COMBOBOX_ARROW);
+      break;
+    default:
+      widget = GetWidget(MOZ_GTK_BUTTON_ARROW);
+      break;
+  }
+  if (widget) {
+    GtkRequisition requisition;
+    gtk_widget_get_preferred_size(widget, NULL, &requisition);
+    moz_gtk_sanity_preferred_size(&requisition);
+
+    *width = requisition.width;
+    *height = requisition.height;
+  } else {
+    *width = 0;
+    *height = 0;
+  }
+}
+
+gint moz_gtk_get_expander_size(gint* size) {
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_EXPANDER);
+  gtk_style_context_get_style(style, "expander-size", size, NULL);
+  return MOZ_GTK_SUCCESS;
+}
+
+gint moz_gtk_get_treeview_expander_size(gint* size) {
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_TREEVIEW);
+  gtk_style_context_get_style(style, "expander-size", size, NULL);
+  return MOZ_GTK_SUCCESS;
+}
+
+void moz_gtk_get_entry_min_height(gint* min_content_height,
+                                  gint* border_padding_height) {
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_ENTRY);
+  if (!gtk_check_version(3, 20, 0)) {
+    gtk_style_context_get(style, gtk_style_context_get_state(style),
+                          "min-height", min_content_height, nullptr);
+  } else {
+    *min_content_height = 0;
+  }
+
+  GtkBorder border;
+  GtkBorder padding;
+  gtk_style_context_get_border(style, gtk_style_context_get_state(style),
+                               &border);
+  gtk_style_context_get_padding(style, gtk_style_context_get_state(style),
+                                &padding);
+
+  *border_padding_height =
+      (border.top + border.bottom + padding.top + padding.bottom);
+}
+
+void moz_gtk_get_scale_metrics(GtkOrientation orient, gint* scale_width,
+                               gint* scale_height) {
+  if (gtk_check_version(3, 20, 0) != nullptr) {
+    WidgetNodeType widget = (orient == GTK_ORIENTATION_HORIZONTAL)
+                                ? MOZ_GTK_SCALE_HORIZONTAL
+                                : MOZ_GTK_SCALE_VERTICAL;
+
+    gint thumb_length, thumb_height, trough_border;
+    moz_gtk_get_scalethumb_metrics(orient, &thumb_length, &thumb_height);
+
+    GtkStyleContext* style = GetStyleContext(widget);
+    gtk_style_context_get_style(style, "trough-border", &trough_border, NULL);
+
+    if (orient == GTK_ORIENTATION_HORIZONTAL) {
+      *scale_width = thumb_length + trough_border * 2;
+      *scale_height = thumb_height + trough_border * 2;
+    } else {
+      *scale_width = thumb_height + trough_border * 2;
+      *scale_height = thumb_length + trough_border * 2;
+    }
+  } else {
+    WidgetNodeType widget = (orient == GTK_ORIENTATION_HORIZONTAL)
+                                ? MOZ_GTK_SCALE_TROUGH_HORIZONTAL
+                                : MOZ_GTK_SCALE_TROUGH_VERTICAL;
+    moz_gtk_get_widget_min_size(GetStyleContext(widget), scale_width,
+                                scale_height);
+  }
+}
+
+gint moz_gtk_get_scalethumb_metrics(GtkOrientation orient, gint* thumb_length,
+                                    gint* thumb_height) {
+  if (gtk_check_version(3, 20, 0) != nullptr) {
+    WidgetNodeType widget = (orient == GTK_ORIENTATION_HORIZONTAL)
+                                ? MOZ_GTK_SCALE_HORIZONTAL
+                                : MOZ_GTK_SCALE_VERTICAL;
+    GtkStyleContext* style = GetStyleContext(widget);
+    gtk_style_context_get_style(style, "slider_length", thumb_length,
+                                "slider_width", thumb_height, NULL);
+  } else {
+    WidgetNodeType widget = (orient == GTK_ORIENTATION_HORIZONTAL)
+                                ? MOZ_GTK_SCALE_THUMB_HORIZONTAL
+                                : MOZ_GTK_SCALE_THUMB_VERTICAL;
+    GtkStyleContext* style = GetStyleContext(widget);
+
+    gint min_width, min_height;
+    GtkStateFlags state = gtk_style_context_get_state(style);
+    gtk_style_context_get(style, state, "min-width", &min_width, "min-height",
+                          &min_height, nullptr);
+    GtkBorder margin;
+    gtk_style_context_get_margin(style, state, &margin);
+    gint margin_width = margin.left + margin.right;
+    gint margin_height = margin.top + margin.bottom;
+
+    // Negative margin of slider element also determines its minimal size
+    // so use bigger of those two values.
+    if (min_width < -margin_width) min_width = -margin_width;
+    if (min_height < -margin_height) min_height = -margin_height;
+
+    *thumb_length = min_width;
+    *thumb_height = min_height;
+  }
+
+  return MOZ_GTK_SUCCESS;
+}
+
+const ToggleGTKMetrics* GetToggleMetrics(WidgetNodeType aWidgetType) {
+  ToggleGTKMetrics* metrics;
+
+  switch (aWidgetType) {
+    case MOZ_GTK_RADIOBUTTON:
+      metrics = &sRadioMetrics;
+      break;
+    case MOZ_GTK_CHECKBUTTON:
+      metrics = &sCheckboxMetrics;
+      break;
+    default:
+      MOZ_CRASH("Unsupported widget type for getting metrics");
+      return nullptr;
+  }
+
+  metrics->initialized = true;
+  if (gtk_check_version(3, 20, 0) == nullptr) {
+    GtkStyleContext* style = GetStyleContext(aWidgetType);
+    GtkStateFlags state_flags = gtk_style_context_get_state(style);
+    gtk_style_context_get(style, state_flags, "min-height",
+                          &(metrics->minSizeWithBorder.height), "min-width",
+                          &(metrics->minSizeWithBorder.width), nullptr);
+    // Fallback to indicator size if min dimensions are zero
+    if (metrics->minSizeWithBorder.height == 0 ||
+        metrics->minSizeWithBorder.width == 0) {
+      gint indicator_size = 0;
+      gtk_widget_style_get(GetWidget(MOZ_GTK_CHECKBUTTON_CONTAINER),
+                           "indicator_size", &indicator_size, nullptr);
+      if (metrics->minSizeWithBorder.height == 0) {
+        metrics->minSizeWithBorder.height = indicator_size;
+      }
+      if (metrics->minSizeWithBorder.width == 0) {
+        metrics->minSizeWithBorder.width = indicator_size;
+      }
+    }
+
+    GtkBorder border, padding;
+    gtk_style_context_get_border(style, state_flags, &border);
+    gtk_style_context_get_padding(style, state_flags, &padding);
+    metrics->borderAndPadding.left = border.left + padding.left;
+    metrics->borderAndPadding.right = border.right + padding.right;
+    metrics->borderAndPadding.top = border.top + padding.top;
+    metrics->borderAndPadding.bottom = border.bottom + padding.bottom;
+    metrics->minSizeWithBorder.width +=
+        metrics->borderAndPadding.left + metrics->borderAndPadding.right;
+    metrics->minSizeWithBorder.height +=
+        metrics->borderAndPadding.top + metrics->borderAndPadding.bottom;
+  } else {
+    gint indicator_size = 0, indicator_spacing = 0;
+    gtk_widget_style_get(GetWidget(MOZ_GTK_CHECKBUTTON_CONTAINER),
+                         "indicator_size", &indicator_size, "indicator_spacing",
+                         &indicator_spacing, nullptr);
+    metrics->minSizeWithBorder.width = metrics->minSizeWithBorder.height =
+        indicator_size;
+  }
+  return metrics;
+}
+
+/*
+ * get_shadow_width() from gtkwindow.c is not public so we need
+ * to implement it.
+ */
+void InitWindowDecorationSize(CSDWindowDecorationSize* sWindowDecorationSize,
+                              bool aPopupWindow) {
+  bool solidDecorations = gtk_style_context_has_class(
+      GetStyleContext(MOZ_GTK_HEADERBAR_WINDOW, 1), "solid-csd");
+  // solid-csd does not use frame extents, quit now.
+  if (solidDecorations) {
+    sWindowDecorationSize->decorationSize = {0, 0, 0, 0};
+    return;
+  }
+
+  // Scale factor is applied later when decoration size is used for actual
+  // gtk windows.
+  GtkStyleContext* context = GetStyleContext(MOZ_GTK_WINDOW_DECORATION);
+
+  /* Always sum border + padding */
+  GtkBorder padding;
+  GtkStateFlags state = gtk_style_context_get_state(context);
+  gtk_style_context_get_border(context, state,
+                               &sWindowDecorationSize->decorationSize);
+  gtk_style_context_get_padding(context, state, &padding);
+  sWindowDecorationSize->decorationSize += padding;
+
+  // Available on GTK 3.20+.
+  static auto sGtkRenderBackgroundGetClip = (void (*)(
+      GtkStyleContext*, gdouble, gdouble, gdouble, gdouble,
+      GdkRectangle*))dlsym(RTLD_DEFAULT, "gtk_render_background_get_clip");
+
+  if (!sGtkRenderBackgroundGetClip) {
+    return;
+  }
+
+  GdkRectangle clip;
+  sGtkRenderBackgroundGetClip(context, 0, 0, 0, 0, &clip);
+
+  GtkBorder extents;
+  extents.top = -clip.y;
+  extents.right = clip.width + clip.x;
+  extents.bottom = clip.height + clip.y;
+  extents.left = -clip.x;
+
+  // Get shadow extents but combine with style margin; use the bigger value.
+  // Margin is used for resize grip size - it's not present on
+  // popup windows.
+  if (!aPopupWindow) {
+    GtkBorder margin;
+    gtk_style_context_get_margin(context, state, &margin);
+
+    extents.top = MAX(extents.top, margin.top);
+    extents.right = MAX(extents.right, margin.right);
+    extents.bottom = MAX(extents.bottom, margin.bottom);
+    extents.left = MAX(extents.left, margin.left);
+  }
+
+  sWindowDecorationSize->decorationSize += extents;
+}
+
+GtkBorder GetCSDDecorationSize(bool aIsPopup) {
+  auto metrics =
+      aIsPopup ? &sPopupWindowDecorationSize : &sToplevelWindowDecorationSize;
+  if (!metrics->initialized) {
+    InitWindowDecorationSize(metrics, aIsPopup);
+    metrics->initialized = true;
+  }
+  return metrics->decorationSize;
+}
+
+/* cairo_t *cr argument has to be a system-cairo. */
+gint moz_gtk_widget_paint(WidgetNodeType widget, cairo_t* cr,
+                          GdkRectangle* rect, GtkWidgetState* state, gint flags,
+                          GtkTextDirection direction) {
+  /* A workaround for https://bugzilla.gnome.org/show_bug.cgi?id=694086
+   */
+  cairo_new_path(cr);
+
+  switch (widget) {
+    case MOZ_GTK_BUTTON:
+    case MOZ_GTK_TOOLBAR_BUTTON:
+      if (state->depressed) {
+        return moz_gtk_button_paint(cr, rect, state, (GtkReliefStyle)flags,
+                                    GetWidget(MOZ_GTK_TOGGLE_BUTTON),
+                                    direction);
+      }
+      return moz_gtk_button_paint(cr, rect, state, (GtkReliefStyle)flags,
+                                  GetWidget(MOZ_GTK_BUTTON), direction);
+    case MOZ_GTK_HEADER_BAR_BUTTON_CLOSE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE:
+    case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE:
+      return moz_gtk_header_bar_button_paint(
+          cr, rect, state, (GtkReliefStyle)flags, widget, direction);
+    case MOZ_GTK_CHECKBUTTON:
+    case MOZ_GTK_RADIOBUTTON:
+      return moz_gtk_toggle_paint(cr, rect, state,
+                                  !!(flags & MOZ_GTK_WIDGET_CHECKED),
+                                  !!(flags & MOZ_GTK_WIDGET_INCONSISTENT),
+                                  (widget == MOZ_GTK_RADIOBUTTON), direction);
+    case MOZ_GTK_SCALE_HORIZONTAL:
+    case MOZ_GTK_SCALE_VERTICAL:
+      return moz_gtk_scale_paint(cr, rect, state, (GtkOrientation)flags,
+                                 direction);
+    case MOZ_GTK_SCALE_THUMB_HORIZONTAL:
+    case MOZ_GTK_SCALE_THUMB_VERTICAL:
+      return moz_gtk_scale_thumb_paint(cr, rect, state, (GtkOrientation)flags,
+                                       direction);
+    case MOZ_GTK_INNER_SPIN_BUTTON:
+      return moz_gtk_inner_spin_paint(cr, rect, state, direction);
+    case MOZ_GTK_SPINBUTTON:
+      return moz_gtk_spin_paint(cr, rect, state, direction);
+    case MOZ_GTK_SPINBUTTON_UP:
+    case MOZ_GTK_SPINBUTTON_DOWN:
+      return moz_gtk_spin_updown_paint(
+          cr, rect, (widget == MOZ_GTK_SPINBUTTON_DOWN), state, direction);
+    case MOZ_GTK_SPINBUTTON_ENTRY: {
+      GtkStyleContext* style =
+          GetStyleContext(MOZ_GTK_SPINBUTTON_ENTRY, state->image_scale,
+                          direction, GetStateFlagsFromGtkWidgetState(state));
+      return moz_gtk_entry_paint(cr, rect, state, style, widget);
+    }
+    case MOZ_GTK_TREEVIEW:
+      return moz_gtk_treeview_paint(cr, rect, state, direction);
+    case MOZ_GTK_TREE_HEADER_CELL:
+      return moz_gtk_tree_header_cell_paint(cr, rect, state, flags, direction);
+    case MOZ_GTK_TREEVIEW_EXPANDER:
+      return moz_gtk_treeview_expander_paint(
+          cr, rect, state, (GtkExpanderStyle)flags, direction);
+    case MOZ_GTK_ENTRY:
+    case MOZ_GTK_DROPDOWN_ENTRY: {
+      GtkStyleContext* style =
+          GetStyleContext(widget, state->image_scale, direction,
+                          GetStateFlagsFromGtkWidgetState(state));
+      gint ret = moz_gtk_entry_paint(cr, rect, state, style, widget);
+      return ret;
+    }
+    case MOZ_GTK_TEXT_VIEW:
+      return moz_gtk_text_view_paint(cr, rect, state, direction);
+    case MOZ_GTK_DROPDOWN:
+      return moz_gtk_combo_box_paint(cr, rect, state, direction);
+    case MOZ_GTK_TOOLTIP:
+      return moz_gtk_tooltip_paint(cr, rect, state, direction);
+    case MOZ_GTK_FRAME:
+      return moz_gtk_frame_paint(cr, rect, state, direction);
+    case MOZ_GTK_RESIZER:
+      return moz_gtk_resizer_paint(cr, rect, state, direction);
+    case MOZ_GTK_PROGRESSBAR:
+      return moz_gtk_progressbar_paint(cr, rect, state, direction);
+    case MOZ_GTK_PROGRESS_CHUNK:
+    case MOZ_GTK_PROGRESS_CHUNK_INDETERMINATE:
+    case MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE:
+      return moz_gtk_progress_chunk_paint(cr, rect, state, direction, widget);
+    case MOZ_GTK_TAB_TOP:
+    case MOZ_GTK_TAB_BOTTOM:
+      return moz_gtk_tab_paint(cr, rect, state, (GtkTabFlags)flags, direction,
+                               widget);
+    case MOZ_GTK_TABPANELS:
+      return moz_gtk_tabpanels_paint(cr, rect, state, direction);
+    case MOZ_GTK_TAB_SCROLLARROW:
+      return moz_gtk_tab_scroll_arrow_paint(cr, rect, state,
+                                            (GtkArrowType)flags, direction);
+    case MOZ_GTK_TOOLBARBUTTON_ARROW:
+      return moz_gtk_arrow_paint(cr, rect, state, (GtkArrowType)flags,
+                                 direction);
+    case MOZ_GTK_SPLITTER_HORIZONTAL:
+      return moz_gtk_vpaned_paint(cr, rect, state);
+    case MOZ_GTK_SPLITTER_VERTICAL:
+      return moz_gtk_hpaned_paint(cr, rect, state);
+    case MOZ_GTK_WINDOW_DECORATION:
+      return moz_gtk_window_decoration_paint(cr, rect, state, direction);
+    case MOZ_GTK_HEADER_BAR:
+    case MOZ_GTK_HEADER_BAR_MAXIMIZED:
+      return moz_gtk_header_bar_paint(widget, cr, rect, state);
+    default:
+      g_warning("Unknown widget type: %d", widget);
+  }
+
+  return MOZ_GTK_UNKNOWN_WIDGET;
+}
+
+gint moz_gtk_shutdown() {
+  /* This will destroy all of our widgets */
+  ResetWidgetCache();
+
+  return MOZ_GTK_SUCCESS;
+}
diff --git a/widget/gtk/gtkdrawing.h b/widget/gtk/gtkdrawing.h
new file mode 100644
index 0000000000..e751dc38c9
--- /dev/null
+++ b/widget/gtk/gtkdrawing.h
@@ -0,0 +1,524 @@
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * gtkdrawing.h: GTK widget rendering utilities
+ *
+ * gtkdrawing provides an API for rendering GTK widgets in the
+ * current theme to a pixmap or window, without requiring an actual
+ * widget instantiation, similar to the Macintosh Appearance Manager
+ * or Windows XP's DrawThemeBackground() API.
+ */
+
+#ifndef _GTK_DRAWING_H_
+#define _GTK_DRAWING_H_
+
+#include <gdk/gdk.h>
+#include <gtk/gtk.h>
+#include <algorithm>
+#include "mozilla/Span.h"
+
+/*** type definitions ***/
+typedef struct {
+  guint8 active;
+  guint8 focused;
+  guint8 selected;
+  guint8 inHover;
+  guint8 disabled;
+  guint8 isDefault;
+  guint8 canDefault;
+  /* The depressed state is for buttons which remain active for a longer period:
+   * activated toggle buttons or buttons showing a popup menu. */
+  guint8 depressed;
+  guint8 backdrop;
+  gint32 curpos; /* curpos and maxpos are used for scrollbars */
+  gint32 maxpos;
+  gint32 image_scale; /* image scale */
+} GtkWidgetState;
+
+/**
+ * A size in the same GTK pixel units as GtkBorder and GdkRectangle.
+ */
+struct MozGtkSize {
+  gint width;
+  gint height;
+
+  MozGtkSize& operator+=(const GtkBorder& aBorder) {
+    width += aBorder.left + aBorder.right;
+    height += aBorder.top + aBorder.bottom;
+    return *this;
+  }
+  MozGtkSize operator+(const GtkBorder& aBorder) const {
+    MozGtkSize result = *this;
+    return result += aBorder;
+  }
+  bool operator<(const MozGtkSize& aOther) const {
+    return (width < aOther.width && height <= aOther.height) ||
+           (width <= aOther.width && height < aOther.height);
+  }
+  void Include(MozGtkSize aOther) {
+    width = std::max(width, aOther.width);
+    height = std::max(height, aOther.height);
+  }
+  void Rotate() {
+    gint tmp = width;
+    width = height;
+    height = tmp;
+  }
+};
+
+typedef struct {
+  bool initialized;
+  MozGtkSize minSizeWithBorder;
+  GtkBorder borderAndPadding;
+} ToggleGTKMetrics;
+
+typedef struct {
+  MozGtkSize minSizeWithBorderMargin;
+  GtkBorder buttonMargin;
+  gint iconXPosition;
+  gint iconYPosition;
+  bool visible;
+  bool firstButton;
+  bool lastButton;
+} ToolbarButtonGTKMetrics;
+
+#define TOOLBAR_BUTTONS 3
+typedef struct {
+  bool initialized;
+  ToolbarButtonGTKMetrics button[TOOLBAR_BUTTONS];
+} ToolbarGTKMetrics;
+
+typedef struct {
+  bool initialized;
+  GtkBorder decorationSize;
+} CSDWindowDecorationSize;
+
+/** flags for tab state **/
+typedef enum {
+  /* first eight bits are used to pass a margin */
+  MOZ_GTK_TAB_MARGIN_MASK = 0xFF,
+  /* the first tab in the group */
+  MOZ_GTK_TAB_FIRST = 1 << 9,
+  /* the selected tab */
+  MOZ_GTK_TAB_SELECTED = 1 << 10
+} GtkTabFlags;
+
+/*** result/error codes ***/
+#define MOZ_GTK_SUCCESS 0
+#define MOZ_GTK_UNKNOWN_WIDGET -1
+#define MOZ_GTK_UNSAFE_THEME -2
+
+/*** checkbox/radio flags ***/
+#define MOZ_GTK_WIDGET_CHECKED 1
+#define MOZ_GTK_WIDGET_INCONSISTENT (1 << 1)
+
+/*** widget type constants ***/
+enum WidgetNodeType : int {
+  /* Paints a GtkButton. flags is a GtkReliefStyle. */
+  MOZ_GTK_BUTTON,
+  /* Paints a button with image and no text */
+  MOZ_GTK_TOOLBAR_BUTTON,
+  /* Paints a toggle button */
+  MOZ_GTK_TOGGLE_BUTTON,
+  /* Paints a button arrow */
+  MOZ_GTK_BUTTON_ARROW,
+
+  /* Paints the container part of a GtkCheckButton. */
+  MOZ_GTK_CHECKBUTTON_CONTAINER,
+  /* Paints a GtkCheckButton. flags is a boolean, 1=checked, 0=not checked. */
+  MOZ_GTK_CHECKBUTTON,
+
+  /* Paints the container part of a GtkRadioButton. */
+  MOZ_GTK_RADIOBUTTON_CONTAINER,
+  /* Paints a GtkRadioButton. flags is a boolean, 1=checked, 0=not checked. */
+  MOZ_GTK_RADIOBUTTON,
+  /* Vertical GtkScrollbar counterparts */
+  MOZ_GTK_SCROLLBAR_VERTICAL,
+  MOZ_GTK_SCROLLBAR_CONTENTS_VERTICAL,
+  MOZ_GTK_SCROLLBAR_TROUGH_VERTICAL,
+  MOZ_GTK_SCROLLBAR_THUMB_VERTICAL,
+
+  /* Paints a GtkScale. */
+  MOZ_GTK_SCALE_HORIZONTAL,
+  MOZ_GTK_SCALE_VERTICAL,
+  /* Paints a GtkScale trough. */
+  MOZ_GTK_SCALE_CONTENTS_HORIZONTAL,
+  MOZ_GTK_SCALE_CONTENTS_VERTICAL,
+  MOZ_GTK_SCALE_TROUGH_HORIZONTAL,
+  MOZ_GTK_SCALE_TROUGH_VERTICAL,
+  /* Paints a GtkScale thumb. */
+  MOZ_GTK_SCALE_THUMB_HORIZONTAL,
+  MOZ_GTK_SCALE_THUMB_VERTICAL,
+  /* Paints a GtkSpinButton */
+  MOZ_GTK_INNER_SPIN_BUTTON,
+  MOZ_GTK_SPINBUTTON,
+  MOZ_GTK_SPINBUTTON_UP,
+  MOZ_GTK_SPINBUTTON_DOWN,
+  MOZ_GTK_SPINBUTTON_ENTRY,
+  /* Paints a GtkEntry. */
+  MOZ_GTK_ENTRY,
+  /* Paints a GtkExpander. */
+  MOZ_GTK_EXPANDER,
+  /* Paints a GtkTextView or gets the style context corresponding to the
+     root node of a GtkTextView. */
+  MOZ_GTK_TEXT_VIEW,
+  /* The "text" window or node of a GtkTextView */
+  MOZ_GTK_TEXT_VIEW_TEXT,
+  /* The "selection" node of a GtkTextView.text */
+  MOZ_GTK_TEXT_VIEW_TEXT_SELECTION,
+  /* Paints a GtkOptionMenu. */
+  MOZ_GTK_DROPDOWN,
+  /* Paints an entry in an editable option menu */
+  MOZ_GTK_DROPDOWN_ENTRY,
+
+  /* Paints a GtkToolTip */
+  MOZ_GTK_TOOLTIP,
+  /* Paints a GtkBox from GtkToolTip  */
+  MOZ_GTK_TOOLTIP_BOX,
+  /* Paints a GtkLabel of GtkToolTip */
+  MOZ_GTK_TOOLTIP_BOX_LABEL,
+  /* Paints a GtkFrame (e.g. a status bar panel). */
+  MOZ_GTK_FRAME,
+  /* Paints the border of a GtkFrame */
+  MOZ_GTK_FRAME_BORDER,
+  /* Paints a resize grip for a GtkTextView */
+  MOZ_GTK_RESIZER,
+  /* Paints a GtkProgressBar. */
+  MOZ_GTK_PROGRESSBAR,
+  /* Paints a trough (track) of a GtkProgressBar */
+  MOZ_GTK_PROGRESS_TROUGH,
+  /* Paints a progress chunk of a GtkProgressBar. */
+  MOZ_GTK_PROGRESS_CHUNK,
+  /* Paints a progress chunk of an indeterminated GtkProgressBar. */
+  MOZ_GTK_PROGRESS_CHUNK_INDETERMINATE,
+  /* Paints a progress chunk of a vertical indeterminated GtkProgressBar. */
+  MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE,
+  /* Used as root style of whole GtkNotebook widget */
+  MOZ_GTK_NOTEBOOK,
+  /* Used as root style of active GtkNotebook area which contains tabs and
+     arrows. */
+  MOZ_GTK_NOTEBOOK_HEADER,
+  /* Paints a tab of a GtkNotebook. flags is a GtkTabFlags, defined above. */
+  MOZ_GTK_TAB_TOP,
+  /* Paints a tab of a GtkNotebook. flags is a GtkTabFlags, defined above. */
+  MOZ_GTK_TAB_BOTTOM,
+  /* Paints the background and border of a GtkNotebook. */
+  MOZ_GTK_TABPANELS,
+  /* Paints a GtkArrow for a GtkNotebook. flags is a GtkArrowType. */
+  MOZ_GTK_TAB_SCROLLARROW,
+  /* Paints the expander and border of a GtkTreeView */
+  MOZ_GTK_TREEVIEW,
+  /* Paints the border of a GtkTreeView */
+  MOZ_GTK_TREEVIEW_VIEW,
+  /* Paints treeheader cells */
+  MOZ_GTK_TREE_HEADER_CELL,
+  /* Paints an expander for a GtkTreeView */
+  MOZ_GTK_TREEVIEW_EXPANDER,
+  /* Paints the background of menus, context menus. */
+  MOZ_GTK_MENUPOPUP,
+  /* Menubar for -moz-headerbar colors */
+  MOZ_GTK_MENUBAR,
+  /* Paints an arrow in a toolbar button. flags is a GtkArrowType. */
+  MOZ_GTK_TOOLBARBUTTON_ARROW,
+  /* Paints items of popup menus. */
+  MOZ_GTK_MENUITEM,
+  /* Menubar menuitem for foreground colors. */
+  MOZ_GTK_MENUBARITEM,
+  /* GtkVPaned base class */
+  MOZ_GTK_SPLITTER_HORIZONTAL,
+  /* GtkHPaned base class */
+  MOZ_GTK_SPLITTER_VERTICAL,
+  /* Paints a GtkVPaned separator */
+  MOZ_GTK_SPLITTER_SEPARATOR_HORIZONTAL,
+  /* Paints a GtkHPaned separator */
+  MOZ_GTK_SPLITTER_SEPARATOR_VERTICAL,
+  /* Paints the background of a window, dialog or page. */
+  MOZ_GTK_WINDOW,
+  /* Used only as a container for MOZ_GTK_HEADER_BAR. */
+  MOZ_GTK_HEADERBAR_WINDOW,
+  /* Used only as a container for MOZ_GTK_HEADER_BAR_MAXIMIZED. */
+  MOZ_GTK_HEADERBAR_WINDOW_MAXIMIZED,
+  /* Used only as a container for MOZ_GTK_HEADER_BAR. */
+  MOZ_GTK_HEADERBAR_FIXED,
+  /* Used only as a container for MOZ_GTK_HEADER_BAR_MAXIMIZED. */
+  MOZ_GTK_HEADERBAR_FIXED_MAXIMIZED,
+  /* Window container for all widgets */
+  MOZ_GTK_WINDOW_CONTAINER,
+  /* Used for widget tree construction. */
+  MOZ_GTK_COMBOBOX,
+  /* Paints a GtkComboBox button widget. */
+  MOZ_GTK_COMBOBOX_BUTTON,
+  /* Paints a GtkComboBox arrow widget. */
+  MOZ_GTK_COMBOBOX_ARROW,
+  /* Paints a GtkComboBox separator widget. */
+  MOZ_GTK_COMBOBOX_SEPARATOR,
+  /* Used for widget tree construction. */
+  MOZ_GTK_COMBOBOX_ENTRY,
+  /* Paints a GtkComboBox entry widget. */
+  MOZ_GTK_COMBOBOX_ENTRY_TEXTAREA,
+  /* Paints a GtkComboBox entry button widget. */
+  MOZ_GTK_COMBOBOX_ENTRY_BUTTON,
+  /* Paints a GtkComboBox entry arrow widget. */
+  MOZ_GTK_COMBOBOX_ENTRY_ARROW,
+  /* Used for scrolled window shell. */
+  MOZ_GTK_SCROLLED_WINDOW,
+  /* Paints a GtkHeaderBar */
+  MOZ_GTK_HEADER_BAR,
+  /* Paints a GtkHeaderBar in maximized state */
+  MOZ_GTK_HEADER_BAR_MAXIMIZED,
+  /* Container for GtkHeaderBar buttons */
+  MOZ_GTK_HEADER_BAR_BUTTON_BOX,
+  /* Paints GtkHeaderBar title buttons.
+   * Keep the order here as MOZ_GTK_HEADER_BAR_BUTTON_* are processed
+   * as an array from MOZ_GTK_HEADER_BAR_BUTTON_CLOSE to the last one.
+   */
+  MOZ_GTK_HEADER_BAR_BUTTON_CLOSE,
+  MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE,
+  MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE,
+
+  /* MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE is a state of
+   * MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE button and it's used as
+   * an icon placeholder only.
+   */
+  MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE,
+
+  /* Client-side window decoration node. Available on GTK 3.20+. */
+  MOZ_GTK_WINDOW_DECORATION,
+  MOZ_GTK_WINDOW_DECORATION_SOLID,
+
+  MOZ_GTK_WIDGET_NODE_COUNT
+};
+
+/* ButtonLayout represents a GTK CSD button and whether its on the left or
+ * right side of the tab bar */
+struct ButtonLayout {
+  WidgetNodeType mType;
+};
+
+/*** General library functions ***/
+/**
+ * Initializes the drawing library.  You must call this function
+ * prior to using any other functionality.
+ * returns: MOZ_GTK_SUCCESS if there were no errors
+ *          MOZ_GTK_UNSAFE_THEME if the current theme engine is known
+ *                               to crash with gtkdrawing.
+ */
+gint moz_gtk_init();
+
+/**
+ * Updates the drawing library when the theme changes.
+ */
+void moz_gtk_refresh();
+
+/**
+ * Perform cleanup of the drawing library. You should call this function
+ * when your program exits, or you no longer need the library.
+ *
+ * returns: MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_shutdown();
+
+/*** Widget drawing ***/
+/**
+ * Paint a widget in the current theme.
+ * widget:    a constant giving the widget to paint
+ * drawable:  the drawable to paint to;
+ *            it's colormap must be moz_gtk_widget_get_colormap().
+ * rect:      the bounding rectangle for the widget
+ * state:     the state of the widget.  ignored for some widgets.
+ * flags:     widget-dependant flags; see the WidgetNodeType definition.
+ * direction: the text direction, to draw the widget correctly LTR and RTL.
+ */
+gint moz_gtk_widget_paint(WidgetNodeType widget, cairo_t* cr,
+                          GdkRectangle* rect, GtkWidgetState* state, gint flags,
+                          GtkTextDirection direction);
+
+/*** Widget metrics ***/
+/**
+ * Get the border size of a widget
+ * left/right:  [OUT] the widget's left/right border
+ * top/bottom:  [OUT] the widget's top/bottom border
+ * direction:   the text direction for the widget.  Callers depend on this
+ *              being used only for MOZ_GTK_DROPDOWN widgets, and cache
+ *              results for other widget types across direction values.
+ *
+ * returns:    MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_get_widget_border(WidgetNodeType widget, gint* left, gint* top,
+                               gint* right, gint* bottom,
+                               GtkTextDirection direction);
+
+/**
+ * Get the border size of a notebook tab
+ * left/right:  [OUT] the tab's left/right border
+ * top/bottom:  [OUT] the tab's top/bottom border
+ * direction:   the text direction for the widget
+ * flags:       tab-dependant flags; see the GtkTabFlags definition.
+ * widget:      tab widget
+ *
+ * returns:    MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_get_tab_border(gint* left, gint* top, gint* right, gint* bottom,
+                            GtkTextDirection direction, GtkTabFlags flags,
+                            WidgetNodeType widget);
+
+/**
+ * Get the desired size of a GtkCheckButton
+ * indicator_size:     [OUT] the indicator size
+ * indicator_spacing:  [OUT] the spacing between the indicator and its
+ *                     container
+ *
+ * returns:    MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_checkbox_get_metrics(gint* indicator_size,
+                                  gint* indicator_spacing);
+
+/**
+ * Get metrics of the toggle (radio or checkbox)
+ * isRadio:            [IN] true when requesting metrics for the radio button
+ * returns:    pointer to ToggleGTKMetrics struct
+ */
+const ToggleGTKMetrics* GetToggleMetrics(WidgetNodeType aWidgetType);
+
+/**
+ * Get the desired size of a GtkRadioButton
+ * indicator_size:     [OUT] the indicator size
+ * indicator_spacing:  [OUT] the spacing between the indicator and its
+ *                     container
+ *
+ * returns:    MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_radio_get_metrics(gint* indicator_size, gint* indicator_spacing);
+
+/**
+ * Some GTK themes draw their indication for the default button outside
+ * the button (e.g. the glow in New Wave). This gets the extra space necessary.
+ *
+ * border_top:  [OUT] extra space to add above
+ * border_left:  [OUT] extra space to add to the left
+ * border_bottom:  [OUT] extra space to add underneath
+ * border_right:  [OUT] extra space to add to the right
+ *
+ * returns:   MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_button_get_default_overflow(gint* border_top, gint* border_left,
+                                         gint* border_bottom,
+                                         gint* border_right);
+
+/**
+ * Gets the minimum size of a GtkScale.
+ * orient:           [IN] the scale orientation
+ * scale_width:      [OUT] the width of the scale
+ * scale_height:     [OUT] the height of the scale
+ */
+void moz_gtk_get_scale_metrics(GtkOrientation orient, gint* scale_width,
+                               gint* scale_height);
+
+/**
+ * Get the desired size of a GtkScale thumb
+ * orient:           [IN] the scale orientation
+ * thumb_length:     [OUT] the length of the thumb
+ * thumb_height:     [OUT] the height of the thumb
+ *
+ * returns:    MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_get_scalethumb_metrics(GtkOrientation orient, gint* thumb_length,
+                                    gint* thumb_height);
+
+/**
+ * Get the desired size of a scroll arrow widget
+ * width:   [OUT] the desired width
+ * height:  [OUT] the desired height
+ *
+ * returns:    MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_get_tab_scroll_arrow_size(gint* width, gint* height);
+
+/**
+ * Get the desired size of an arrow in a button
+ *
+ * widgetType: [IN]  the widget for which to get the arrow size
+ * width:      [OUT] the desired width
+ * height:     [OUT] the desired height
+ */
+void moz_gtk_get_arrow_size(WidgetNodeType widgetType, gint* width,
+                            gint* height);
+
+/**
+ * Get the minimum height of a entry widget
+ * min_content_height:    [OUT] the minimum height of the content box.
+ * border_padding_height: [OUT] the size of borders and paddings.
+ */
+void moz_gtk_get_entry_min_height(gint* min_content_height,
+                                  gint* border_padding_height);
+
+/**
+ * Get the desired size of a toolbar separator
+ * size:    [OUT] the desired width
+ *
+ * returns: MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_get_toolbar_separator_width(gint* size);
+
+/**
+ * Get the size of a regular GTK expander that shows/hides content
+ * size:    [OUT] the size of the GTK expander, size = width = height.
+ *
+ * returns:    MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_get_expander_size(gint* size);
+
+/**
+ * Get the size of a treeview's expander (we call them twisties)
+ * size:    [OUT] the size of the GTK expander, size = width = height.
+ *
+ * returns:    MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_get_treeview_expander_size(gint* size);
+
+/**
+ * Get the desired size of a splitter
+ * orientation:   [IN]  GTK_ORIENTATION_HORIZONTAL or GTK_ORIENTATION_VERTICAL
+ * size:          [OUT] width or height of the splitter handle
+ *
+ * returns:    MOZ_GTK_SUCCESS if there was no error, an error code otherwise
+ */
+gint moz_gtk_splitter_get_metrics(gint orientation, gint* size);
+
+/**
+ * Get the YTHICKNESS of a tab (notebook extension).
+ */
+gint moz_gtk_get_tab_thickness(WidgetNodeType aNodeType);
+
+/**
+ * Get ToolbarButtonGTKMetrics for recent theme.
+ */
+const ToolbarButtonGTKMetrics* GetToolbarButtonMetrics(
+    WidgetNodeType aAppearance);
+
+/**
+ * Get toolbar button layout.
+ * aButtonLayout:  [OUT] An array which will be filled by ButtonLayout
+ *                       references to visible titlebar buttons. Must contain at
+ *                       least TOOLBAR_BUTTONS entries if non-empty.
+ * aReversedButtonsPlacement: [OUT] True if the buttons are placed in opposite
+ *                                  titlebar corner.
+ *
+ * returns:    Number of returned entries at aButtonLayout.
+ */
+size_t GetGtkHeaderBarButtonLayout(mozilla::Span<ButtonLayout>,
+                                   bool* aReversedButtonsPlacement);
+
+/**
+ * Get size of CSD window extents.
+ *
+ * aIsPopup: [IN] Get decoration size for popup or toplevel window.
+ *
+ * returns: Calculated (or estimated) decoration size of given aGtkWindow.
+ */
+GtkBorder GetCSDDecorationSize(bool aIsPopup);
+
+#endif
diff --git a/widget/gtk/moz.build b/widget/gtk/moz.build
new file mode 100644
index 0000000000..0d3916853c
--- /dev/null
+++ b/widget/gtk/moz.build
@@ -0,0 +1,179 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "Widget: Gtk")
+
+with Files("*CompositorWidget*"):
+    BUG_COMPONENT = ("Core", "Graphics")
+
+with Files("*WindowSurface*"):
+    BUG_COMPONENT = ("Core", "Graphics")
+
+with Files("*IMContextWrapper*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*nsGtkKeyUtils*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+if CONFIG["COMPILE_ENVIRONMENT"]:
+    DIRS += ["mozgtk"]
+
+if CONFIG["MOZ_WAYLAND"]:
+    DIRS += ["wayland", "mozwayland", "../../third_party/wayland-proxy"]
+
+if CONFIG["MOZ_ENABLE_VAAPI"]:
+    DIRS += ["vaapitest"]
+
+if CONFIG["MOZ_ENABLE_V4L2"]:
+    DIRS += ["v4l2test"]
+
+EXPORTS += [
+    "MozContainer.h",
+    "nsGTKToolkit.h",
+    "nsGtkUtils.h",
+    "nsImageToPixbuf.h",
+]
+
+EXPORTS.mozilla += [
+    "GfxInfo.h",
+    "GfxInfoUtils.h",
+    "GRefPtr.h",
+    "GUniquePtr.h",
+    "WidgetUtilsGtk.h",
+]
+
+EXPORTS.mozilla.widget += [
+    "CompositorWidgetChild.h",
+    "CompositorWidgetParent.h",
+    "DMABufLibWrapper.h",
+    "DMABufSurface.h",
+    "gbm.h",
+    "GtkCompositorWidget.h",
+    "InProcessGtkCompositorWidget.h",
+    "va_drmcommon.h",
+    "WindowSurface.h",
+    "WindowSurfaceProvider.h",
+]
+
+UNIFIED_SOURCES += [
+    "AsyncGtkClipboardRequest.cpp",
+    "CompositorWidgetChild.cpp",
+    "CompositorWidgetParent.cpp",
+    "DMABufLibWrapper.cpp",
+    "DMABufSurface.cpp",
+    "GfxInfo.cpp",
+    "gtk3drawing.cpp",
+    "GtkCompositorWidget.cpp",
+    "IMContextWrapper.cpp",
+    "InProcessGtkCompositorWidget.cpp",
+    "MozContainer.cpp",
+    "MPRISServiceHandler.cpp",
+    "NativeKeyBindings.cpp",
+    "NativeMenuGtk.cpp",
+    "NativeMenuSupport.cpp",
+    "nsApplicationChooser.cpp",
+    "nsAppShell.cpp",
+    "nsBidiKeyboard.cpp",
+    "nsClipboard.cpp",
+    "nsColorPicker.cpp",
+    "nsDragService.cpp",
+    "nsFilePicker.cpp",
+    "nsGtkKeyUtils.cpp",
+    "nsImageToPixbuf.cpp",
+    "nsLookAndFeel.cpp",
+    "nsSound.cpp",
+    "nsToolkit.cpp",
+    "nsUserIdleServiceGTK.cpp",
+    "nsWidgetFactory.cpp",
+    "ScreenHelperGTK.cpp",
+    "TaskbarProgress.cpp",
+    "WakeLockListener.cpp",
+    "WidgetStyleCache.cpp",
+    "WidgetTraceEvent.cpp",
+    "WidgetUtilsGtk.cpp",
+    "WindowSurfaceProvider.cpp",
+]
+
+SOURCES += [
+    "MediaKeysEventSourceFactory.cpp",
+    "nsNativeThemeGTK.cpp",  # conflicts with X11 headers
+    "nsWindow.cpp",  # conflicts with X11 headers
+    "WaylandVsyncSource.cpp",  # conflicts with X11 headers
+]
+
+if CONFIG["MOZ_WAYLAND"]:
+    UNIFIED_SOURCES += [
+        "MozContainerWayland.cpp",
+        "nsClipboardWayland.cpp",
+        "nsWaylandDisplay.cpp",
+        "WaylandBuffer.cpp",
+        "WindowSurfaceWaylandMultiBuffer.cpp",
+    ]
+    EXPORTS.mozilla.widget += [
+        "MozContainerWayland.h",
+        "nsWaylandDisplay.h",
+        "WaylandBuffer.h",
+    ]
+
+if CONFIG["MOZ_X11"]:
+    UNIFIED_SOURCES += [
+        "nsClipboardX11.cpp",
+        "nsShmImage.cpp",
+        "WindowSurfaceX11.cpp",
+        "WindowSurfaceX11Image.cpp",
+        "WindowSurfaceX11SHM.cpp",
+    ]
+
+if CONFIG["NS_PRINTING"]:
+    UNIFIED_SOURCES += [
+        "nsDeviceContextSpecG.cpp",
+        "nsPrintDialogGTK.cpp",
+        "nsPrintSettingsGTK.cpp",
+        "nsPrintSettingsServiceGTK.cpp",
+    ]
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
+
+LOCAL_INCLUDES += [
+    "/layout/base",
+    "/layout/forms",
+    "/layout/generic",
+    "/layout/xul",
+    "/other-licenses/atk-1.0",
+    "/third_party/cups/include",
+    "/widget",
+    "/widget/headless",
+    "/widget/x11",
+]
+
+DEFINES["CAIRO_GFX"] = True
+
+DEFINES["MOZ_APP_NAME"] = '"%s"' % CONFIG["MOZ_APP_NAME"]
+
+CFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
+CXXFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
+
+if CONFIG["MOZ_WAYLAND"]:
+    CFLAGS += CONFIG["MOZ_WAYLAND_CFLAGS"]
+    CXXFLAGS += CONFIG["MOZ_WAYLAND_CFLAGS"]
+
+if CONFIG["MOZ_ENABLE_DBUS"]:
+    EXPORTS.mozilla.widget += [
+        "AsyncDBus.h",
+    ]
+    UNIFIED_SOURCES += [
+        "AsyncDBus.cpp",
+    ]
+    CXXFLAGS += CONFIG["MOZ_DBUS_CFLAGS"]
+
+CXXFLAGS += ["-Werror=switch"]
diff --git a/widget/gtk/mozgtk/moz.build b/widget/gtk/mozgtk/moz.build
new file mode 100644
index 0000000000..d5e78d0032
--- /dev/null
+++ b/widget/gtk/mozgtk/moz.build
@@ -0,0 +1,37 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+SharedLibrary("mozgtk")
+
+SOURCES += [
+    "mozgtk.c",
+]
+
+CFLAGS += CONFIG["MOZ_X11_CFLAGS"]
+CFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
+
+# If LDFLAGS contains -Wl,--as-needed or if it's the default for the toolchain,
+# we need to add -Wl,--no-as-needed before the gtk libraries, otherwise the
+# linker will drop those dependencies because no symbols are used from them.
+# But those dependencies need to be kept for things to work properly.
+# Ideally, we'd only add -Wl,--no-as-needed if necessary, but it's just simpler
+# to add it unconditionally. This library is also simple enough that forcing
+# -Wl,--as-needed after the gtk libraries is not going to make a significant
+# difference.
+if CONFIG["GCC_USE_GNU_LD"]:
+    no_as_needed = ["-Wl,--no-as-needed"]
+    as_needed = ["-Wl,--as-needed"]
+else:
+    no_as_needed = []
+    as_needed = []
+
+OS_LIBS += [f for f in CONFIG["MOZ_GTK3_LIBS"] if f.startswith("-L")]
+OS_LIBS += no_as_needed
+OS_LIBS += [
+    "gtk-3",
+    "gdk-3",
+]
+OS_LIBS += as_needed
diff --git a/widget/gtk/mozgtk/mozgtk.c b/widget/gtk/mozgtk/mozgtk.c
new file mode 100644
index 0000000000..d95746fc0b
--- /dev/null
+++ b/widget/gtk/mozgtk/mozgtk.c
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Types.h"
+
+#include <gdk/gdk.h>
+
+// Dummy call to gtk3 library to prevent the linker from removing
+// the gtk3 dependency with --as-needed.
+// see toolkit/library/moz.build for details.
+MOZ_EXPORT void mozgtk_linker_holder() { gdk_display_get_default(); }
+
+#ifdef MOZ_X11
+#  include <X11/Xlib.h>
+// Bug 1271100
+// We need to trick system Cairo into not using the XShm extension due to
+// a race condition in it that results in frequent BadAccess errors. Cairo
+// relies upon XShmQueryExtension to initially detect if XShm is available.
+// So we define our own stub that always indicates XShm not being present.
+// mozgtk loads before libXext/libcairo and so this stub will take priority.
+// Our tree usage goes through xcb and remains unaffected by this.
+//
+// This is also used to force libxul to depend on the mozgtk library. If we
+// ever can remove this workaround for system Cairo, we'll need something
+// to replace it for that purpose.
+MOZ_EXPORT Bool XShmQueryExtension(Display* aDisplay) { return False; }
+#endif
diff --git a/widget/gtk/mozwayland/moz.build b/widget/gtk/mozwayland/moz.build
new file mode 100644
index 0000000000..0df3f0f685
--- /dev/null
+++ b/widget/gtk/mozwayland/moz.build
@@ -0,0 +1,16 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+SOURCES += [
+    "mozwayland.c",
+]
+EXPORTS.mozilla.widget += [
+    "mozwayland.h",
+]
+
+SharedLibrary("mozwayland")
+
+CFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
diff --git a/widget/gtk/mozwayland/mozwayland.c b/widget/gtk/mozwayland/mozwayland.c
new file mode 100644
index 0000000000..eb17d3227e
--- /dev/null
+++ b/widget/gtk/mozwayland/mozwayland.c
@@ -0,0 +1,230 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <stdlib.h>
+#include "mozilla/Types.h"
+#include <gtk/gtk.h>
+#include <gtk/gtkx.h>
+#include <gdk/gdkwayland.h>
+
+union wl_argument;
+
+/* Those structures are just placeholders and will be replaced by
+ * real symbols from libwayland during run-time linking. We need to make
+ * them explicitly visible.
+ */
+#pragma GCC visibility push(default)
+const struct wl_interface wl_buffer_interface;
+const struct wl_interface wl_callback_interface;
+const struct wl_interface wl_data_device_interface;
+const struct wl_interface wl_data_device_manager_interface;
+const struct wl_interface wl_keyboard_interface;
+const struct wl_interface wl_pointer_interface;
+const struct wl_interface wl_region_interface;
+const struct wl_interface wl_registry_interface;
+const struct wl_interface wl_shm_interface;
+const struct wl_interface wl_shm_pool_interface;
+const struct wl_interface wl_seat_interface;
+const struct wl_interface wl_surface_interface;
+const struct wl_interface wl_subsurface_interface;
+const struct wl_interface wl_compositor_interface;
+const struct wl_interface wl_subcompositor_interface;
+const struct wl_interface wl_output_interface;
+#pragma GCC visibility pop
+
+MOZ_EXPORT void wl_event_queue_destroy(struct wl_event_queue* queue) {}
+
+MOZ_EXPORT void wl_proxy_marshal(struct wl_proxy* p, uint32_t opcode, ...) {}
+
+MOZ_EXPORT void wl_proxy_marshal_array(struct wl_proxy* p, uint32_t opcode,
+                                       union wl_argument* args) {}
+
+MOZ_EXPORT struct wl_proxy* wl_proxy_create(
+    struct wl_proxy* factory, const struct wl_interface* interface) {
+  return NULL;
+}
+
+MOZ_EXPORT void* wl_proxy_create_wrapper(void* proxy) { return NULL; }
+
+MOZ_EXPORT void wl_proxy_wrapper_destroy(void* proxy_wrapper) {}
+
+MOZ_EXPORT struct wl_proxy* wl_proxy_marshal_constructor(
+    struct wl_proxy* proxy, uint32_t opcode,
+    const struct wl_interface* interface, ...) {
+  return NULL;
+}
+
+MOZ_EXPORT struct wl_proxy* wl_proxy_marshal_constructor_versioned(
+    struct wl_proxy* proxy, uint32_t opcode,
+    const struct wl_interface* interface, uint32_t version, ...) {
+  return NULL;
+}
+
+MOZ_EXPORT struct wl_proxy* wl_proxy_marshal_array_constructor(
+    struct wl_proxy* proxy, uint32_t opcode, union wl_argument* args,
+    const struct wl_interface* interface) {
+  return NULL;
+}
+
+MOZ_EXPORT struct wl_proxy* wl_proxy_marshal_array_constructor_versioned(
+    struct wl_proxy* proxy, uint32_t opcode, union wl_argument* args,
+    const struct wl_interface* interface, uint32_t version) {
+  return NULL;
+}
+
+MOZ_EXPORT void wl_proxy_destroy(struct wl_proxy* proxy) {}
+
+MOZ_EXPORT int wl_proxy_add_listener(struct wl_proxy* proxy,
+                                     void (**implementation)(void),
+                                     void* data) {
+  return -1;
+}
+
+MOZ_EXPORT const void* wl_proxy_get_listener(struct wl_proxy* proxy) {
+  return NULL;
+}
+
+typedef int (*wl_dispatcher_func_t)(const void*, void*, uint32_t,
+                                    const struct wl_message*,
+                                    union wl_argument*);
+
+MOZ_EXPORT int wl_proxy_add_dispatcher(struct wl_proxy* proxy,
+                                       wl_dispatcher_func_t dispatcher_func,
+                                       const void* dispatcher_data,
+                                       void* data) {
+  return -1;
+}
+
+MOZ_EXPORT void wl_proxy_set_user_data(struct wl_proxy* proxy,
+                                       void* user_data) {}
+
+MOZ_EXPORT void* wl_proxy_get_user_data(struct wl_proxy* proxy) { return NULL; }
+
+MOZ_EXPORT uint32_t wl_proxy_get_version(struct wl_proxy* proxy) { return -1; }
+
+MOZ_EXPORT uint32_t wl_proxy_get_id(struct wl_proxy* proxy) { return -1; }
+
+MOZ_EXPORT const char* wl_proxy_get_class(struct wl_proxy* proxy) {
+  return NULL;
+}
+
+MOZ_EXPORT void wl_proxy_set_queue(struct wl_proxy* proxy,
+                                   struct wl_event_queue* queue) {}
+
+MOZ_EXPORT struct wl_display* wl_display_connect(const char* name) {
+  return NULL;
+}
+
+MOZ_EXPORT struct wl_display* wl_display_connect_to_fd(int fd) { return NULL; }
+
+MOZ_EXPORT void wl_display_disconnect(struct wl_display* display) {}
+
+MOZ_EXPORT int wl_display_get_fd(struct wl_display* display) { return -1; }
+
+MOZ_EXPORT int wl_display_dispatch(struct wl_display* display) { return -1; }
+
+MOZ_EXPORT int wl_display_dispatch_queue(struct wl_display* display,
+                                         struct wl_event_queue* queue) {
+  return -1;
+}
+
+MOZ_EXPORT int wl_display_dispatch_queue_pending(struct wl_display* display,
+                                                 struct wl_event_queue* queue) {
+  return -1;
+}
+
+MOZ_EXPORT int wl_display_dispatch_pending(struct wl_display* display) {
+  return -1;
+}
+
+MOZ_EXPORT int wl_display_get_error(struct wl_display* display) { return -1; }
+
+MOZ_EXPORT uint32_t wl_display_get_protocol_error(
+    struct wl_display* display, const struct wl_interface** interface,
+    uint32_t* id) {
+  return -1;
+}
+
+MOZ_EXPORT int wl_display_flush(struct wl_display* display) { return -1; }
+
+MOZ_EXPORT int wl_display_roundtrip_queue(struct wl_display* display,
+                                          struct wl_event_queue* queue) {
+  return -1;
+}
+
+MOZ_EXPORT int wl_display_roundtrip(struct wl_display* display) { return -1; }
+
+MOZ_EXPORT struct wl_event_queue* wl_display_create_queue(
+    struct wl_display* display) {
+  return NULL;
+}
+
+MOZ_EXPORT int wl_display_prepare_read_queue(struct wl_display* display,
+                                             struct wl_event_queue* queue) {
+  return -1;
+}
+
+MOZ_EXPORT int wl_display_prepare_read(struct wl_display* display) {
+  return -1;
+}
+
+MOZ_EXPORT void wl_display_cancel_read(struct wl_display* display) {}
+
+MOZ_EXPORT int wl_display_read_events(struct wl_display* display) { return -1; }
+
+MOZ_EXPORT void wl_log_set_handler_client(wl_log_func_t handler) {}
+
+MOZ_EXPORT struct wl_egl_window* wl_egl_window_create(
+    struct wl_surface* surface, int width, int height) {
+  return NULL;
+}
+
+MOZ_EXPORT void wl_egl_window_destroy(struct wl_egl_window* egl_window) {}
+
+MOZ_EXPORT void wl_egl_window_resize(struct wl_egl_window* egl_window,
+                                     int width, int height, int dx, int dy) {}
+
+MOZ_EXPORT void wl_egl_window_get_attached_size(
+    struct wl_egl_window* egl_window, int* width, int* height) {}
+
+MOZ_EXPORT void wl_list_init(struct wl_list* list) {}
+
+MOZ_EXPORT void wl_list_insert(struct wl_list* list, struct wl_list* elm) {}
+
+MOZ_EXPORT void wl_list_remove(struct wl_list* elm) {}
+
+MOZ_EXPORT int wl_list_length(const struct wl_list* list) { return -1; }
+
+MOZ_EXPORT int wl_list_empty(const struct wl_list* list) { return -1; }
+
+MOZ_EXPORT void wl_list_insert_list(struct wl_list* list,
+                                    struct wl_list* other) {}
+
+MOZ_EXPORT struct wl_proxy* wl_proxy_marshal_flags(
+    struct wl_proxy* proxy, uint32_t opcode,
+    const struct wl_interface* interface, uint32_t version, uint32_t flags,
+    ...) {
+  return NULL;
+}
+
+MOZ_EXPORT struct wl_compositor* gdk_wayland_display_get_wl_compositor(
+    GdkDisplay* display) {
+  return NULL;
+}
+MOZ_EXPORT struct wl_surface* gdk_wayland_window_get_wl_surface(
+    GdkWindow* window) {
+  return NULL;
+}
+
+MOZ_EXPORT struct wl_pointer* gdk_wayland_device_get_wl_pointer(
+    GdkDevice* device) {
+  return NULL;
+}
+MOZ_EXPORT struct wl_display* gdk_wayland_display_get_wl_display(
+    GdkDisplay* display) {
+  return NULL;
+}
diff --git a/widget/gtk/mozwayland/mozwayland.h b/widget/gtk/mozwayland/mozwayland.h
new file mode 100644
index 0000000000..22f80d6315
--- /dev/null
+++ b/widget/gtk/mozwayland/mozwayland.h
@@ -0,0 +1,134 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Wayland compatibility header, it makes Firefox build with
+   wayland-1.2 and Gtk+ 3.10.
+*/
+
+#ifndef __MozWayland_h_
+#define __MozWayland_h_
+
+#include "mozilla/Types.h"
+#include <gtk/gtk.h>
+#include <gdk/gdkwayland.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+MOZ_EXPORT struct wl_display* wl_display_connect(const char* name);
+MOZ_EXPORT int wl_display_roundtrip_queue(struct wl_display* display,
+                                          struct wl_event_queue* queue);
+MOZ_EXPORT uint32_t wl_proxy_get_version(struct wl_proxy* proxy);
+MOZ_EXPORT void wl_proxy_marshal(struct wl_proxy* p, uint32_t opcode, ...);
+MOZ_EXPORT struct wl_proxy* wl_proxy_marshal_constructor(
+    struct wl_proxy* proxy, uint32_t opcode,
+    const struct wl_interface* interface, ...);
+MOZ_EXPORT struct wl_proxy* wl_proxy_marshal_constructor_versioned(
+    struct wl_proxy* proxy, uint32_t opcode,
+    const struct wl_interface* interface, uint32_t version, ...);
+MOZ_EXPORT void wl_proxy_destroy(struct wl_proxy* proxy);
+MOZ_EXPORT void* wl_proxy_create_wrapper(void* proxy);
+MOZ_EXPORT void wl_proxy_wrapper_destroy(void* proxy_wrapper);
+
+/* We need implement some missing functions from wayland-client-protocol.h
+ */
+#ifndef WL_DATA_DEVICE_MANAGER_DND_ACTION_ENUM
+enum wl_data_device_manager_dnd_action {
+  WL_DATA_DEVICE_MANAGER_DND_ACTION_NONE = 0,
+  WL_DATA_DEVICE_MANAGER_DND_ACTION_COPY = 1,
+  WL_DATA_DEVICE_MANAGER_DND_ACTION_MOVE = 2,
+  WL_DATA_DEVICE_MANAGER_DND_ACTION_ASK = 4
+};
+#endif
+
+#ifndef WL_DATA_OFFER_SET_ACTIONS
+#  define WL_DATA_OFFER_SET_ACTIONS 4
+
+struct moz_wl_data_offer_listener {
+  void (*offer)(void* data, struct wl_data_offer* wl_data_offer,
+                const char* mime_type);
+  void (*source_actions)(void* data, struct wl_data_offer* wl_data_offer,
+                         uint32_t source_actions);
+  void (*action)(void* data, struct wl_data_offer* wl_data_offer,
+                 uint32_t dnd_action);
+};
+
+static inline void wl_data_offer_set_actions(
+    struct wl_data_offer* wl_data_offer, uint32_t dnd_actions,
+    uint32_t preferred_action) {
+  wl_proxy_marshal((struct wl_proxy*)wl_data_offer, WL_DATA_OFFER_SET_ACTIONS,
+                   dnd_actions, preferred_action);
+}
+#else
+typedef struct wl_data_offer_listener moz_wl_data_offer_listener;
+#endif
+
+#ifndef WL_SUBCOMPOSITOR_GET_SUBSURFACE
+#  define WL_SUBCOMPOSITOR_GET_SUBSURFACE 1
+struct wl_subcompositor;
+
+// Emulate what mozilla header wrapper does - make the
+// wl_subcompositor_interface always visible.
+#  pragma GCC visibility push(default)
+extern const struct wl_interface wl_subsurface_interface;
+extern const struct wl_interface wl_subcompositor_interface;
+#  pragma GCC visibility pop
+
+#  define WL_SUBSURFACE_DESTROY 0
+#  define WL_SUBSURFACE_SET_POSITION 1
+#  define WL_SUBSURFACE_PLACE_ABOVE 2
+#  define WL_SUBSURFACE_PLACE_BELOW 3
+#  define WL_SUBSURFACE_SET_SYNC 4
+#  define WL_SUBSURFACE_SET_DESYNC 5
+
+static inline struct wl_subsurface* wl_subcompositor_get_subsurface(
+    struct wl_subcompositor* wl_subcompositor, struct wl_surface* surface,
+    struct wl_surface* parent) {
+  struct wl_proxy* id;
+
+  id = wl_proxy_marshal_constructor(
+      (struct wl_proxy*)wl_subcompositor, WL_SUBCOMPOSITOR_GET_SUBSURFACE,
+      &wl_subsurface_interface, NULL, surface, parent);
+
+  return (struct wl_subsurface*)id;
+}
+
+static inline void wl_subsurface_set_position(
+    struct wl_subsurface* wl_subsurface, int32_t x, int32_t y) {
+  wl_proxy_marshal((struct wl_proxy*)wl_subsurface, WL_SUBSURFACE_SET_POSITION,
+                   x, y);
+}
+
+static inline void wl_subsurface_set_desync(
+    struct wl_subsurface* wl_subsurface) {
+  wl_proxy_marshal((struct wl_proxy*)wl_subsurface, WL_SUBSURFACE_SET_DESYNC);
+}
+
+static inline void wl_subsurface_destroy(struct wl_subsurface* wl_subsurface) {
+  wl_proxy_marshal((struct wl_proxy*)wl_subsurface, WL_SUBSURFACE_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)wl_subsurface);
+}
+#endif
+
+#ifndef WL_SURFACE_DAMAGE_BUFFER
+#  define WL_SURFACE_DAMAGE_BUFFER 9
+
+static inline void wl_surface_damage_buffer(struct wl_surface* wl_surface,
+                                            int32_t x, int32_t y, int32_t width,
+                                            int32_t height) {
+  wl_proxy_marshal((struct wl_proxy*)wl_surface, WL_SURFACE_DAMAGE_BUFFER, x, y,
+                   width, height);
+}
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __MozWayland_h_ */
diff --git a/widget/gtk/nsAppShell.cpp b/widget/gtk/nsAppShell.cpp
new file mode 100644
index 0000000000..d26b43737d
--- /dev/null
+++ b/widget/gtk/nsAppShell.cpp
@@ -0,0 +1,494 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <gdk/gdk.h>
+#include "nsAppShell.h"
+#include "nsBaseAppShell.h"
+#include "nsWindow.h"
+#include "mozilla/Logging.h"
+#include "prenv.h"
+#include "mozilla/BackgroundHangMonitor.h"
+#include "mozilla/Hal.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/ProfilerThreadSleep.h"
+#include "mozilla/Unused.h"
+#include "mozilla/GUniquePtr.h"
+#include "mozilla/WidgetUtils.h"
+#include "nsIPowerManagerService.h"
+#ifdef MOZ_ENABLE_DBUS
+#  include <gio/gio.h>
+#  include "nsIObserverService.h"
+#  include "WidgetUtilsGtk.h"
+#endif
+#include "WakeLockListener.h"
+#include "gfxPlatform.h"
+#include "nsAppRunner.h"
+#include "mozilla/XREAppData.h"
+#include "ScreenHelperGTK.h"
+#include "HeadlessScreenHelper.h"
+#include "mozilla/widget/ScreenManager.h"
+#ifdef MOZ_WAYLAND
+#  include "nsWaylandDisplay.h"
+#endif
+
+using namespace mozilla;
+using namespace mozilla::widget;
+using mozilla::widget::HeadlessScreenHelper;
+using mozilla::widget::ScreenHelperGTK;
+using mozilla::widget::ScreenManager;
+
+#define NOTIFY_TOKEN 0xFA
+#define QUIT_TOKEN 0xFB
+
+LazyLogModule gWidgetLog("Widget");
+LazyLogModule gWidgetDragLog("WidgetDrag");
+LazyLogModule gWidgetWaylandLog("WidgetWayland");
+LazyLogModule gWidgetPopupLog("WidgetPopup");
+LazyLogModule gWidgetVsync("WidgetVsync");
+LazyLogModule gDmabufLog("Dmabuf");
+LazyLogModule gClipboardLog("WidgetClipboard");
+
+static GPollFunc sPollFunc;
+
+nsAppShell* sAppShell = nullptr;
+
+// Wrapper function to disable hang monitoring while waiting in poll().
+static gint PollWrapper(GPollFD* aUfds, guint aNfsd, gint aTimeout) {
+  if (aTimeout == 0) {
+    // When the timeout is 0, there is no wait, so no point in notifying
+    // the BackgroundHangMonitor and the profiler.
+    return (*sPollFunc)(aUfds, aNfsd, aTimeout);
+  }
+
+  mozilla::BackgroundHangMonitor().NotifyWait();
+  gint result;
+  {
+    gint timeout = aTimeout;
+    gint64 begin = 0;
+    if (aTimeout != -1) {
+      begin = g_get_monotonic_time();
+    }
+
+    AUTO_PROFILER_LABEL("PollWrapper", IDLE);
+    AUTO_PROFILER_THREAD_SLEEP;
+    do {
+      result = (*sPollFunc)(aUfds, aNfsd, timeout);
+
+      // The result will be -1 with the EINTR error if the poll was interrupted
+      // by a signal, typically the signal sent by the profiler to sample the
+      // process. We are only done waiting if we are not in that case.
+      if (result != -1 || errno != EINTR) {
+        break;
+      }
+
+      if (aTimeout != -1) {
+        // Adjust the timeout to account for the time already spent waiting.
+        gint elapsedSinceBegin = (g_get_monotonic_time() - begin) / 1000;
+        if (elapsedSinceBegin < aTimeout) {
+          timeout = aTimeout - elapsedSinceBegin;
+        } else {
+          // poll returns 0 to indicate the call timed out before any fd
+          // became ready.
+          result = 0;
+          break;
+        }
+      }
+    } while (true);
+  }
+  mozilla::BackgroundHangMonitor().NotifyActivity();
+  return result;
+}
+
+// Emit resume-events on GdkFrameClock if flush-events has not been
+// balanced by resume-events at dispose.
+// For https://bugzilla.gnome.org/show_bug.cgi?id=742636
+static decltype(GObjectClass::constructed) sRealGdkFrameClockConstructed;
+static decltype(GObjectClass::dispose) sRealGdkFrameClockDispose;
+static GQuark sPendingResumeQuark;
+
+static void OnFlushEvents(GObject* clock, gpointer) {
+  g_object_set_qdata(clock, sPendingResumeQuark, GUINT_TO_POINTER(1));
+}
+
+static void OnResumeEvents(GObject* clock, gpointer) {
+  g_object_set_qdata(clock, sPendingResumeQuark, nullptr);
+}
+
+static void WrapGdkFrameClockConstructed(GObject* object) {
+  sRealGdkFrameClockConstructed(object);
+
+  g_signal_connect(object, "flush-events", G_CALLBACK(OnFlushEvents), nullptr);
+  g_signal_connect(object, "resume-events", G_CALLBACK(OnResumeEvents),
+                   nullptr);
+}
+
+static void WrapGdkFrameClockDispose(GObject* object) {
+  if (g_object_get_qdata(object, sPendingResumeQuark)) {
+    g_signal_emit_by_name(object, "resume-events");
+  }
+
+  sRealGdkFrameClockDispose(object);
+}
+
+/*static*/
+gboolean nsAppShell::EventProcessorCallback(GIOChannel* source,
+                                            GIOCondition condition,
+                                            gpointer data) {
+  nsAppShell* self = static_cast<nsAppShell*>(data);
+
+  unsigned char c;
+  Unused << read(self->mPipeFDs[0], &c, 1);
+  switch (c) {
+    case NOTIFY_TOKEN:
+      self->NativeEventCallback();
+      break;
+    case QUIT_TOKEN:
+      self->Exit();
+      break;
+    default:
+      NS_ASSERTION(false, "wrong token");
+      break;
+  }
+  return TRUE;
+}
+
+nsAppShell::~nsAppShell() {
+  sAppShell = nullptr;
+
+#ifdef MOZ_ENABLE_DBUS
+  StopDBusListening();
+#endif
+  mozilla::hal::Shutdown();
+
+  if (mTag) g_source_remove(mTag);
+  if (mPipeFDs[0]) close(mPipeFDs[0]);
+  if (mPipeFDs[1]) close(mPipeFDs[1]);
+}
+
+mozilla::StaticRefPtr<WakeLockListener> sWakeLockListener;
+static void AddScreenWakeLockListener() {
+  nsCOMPtr<nsIPowerManagerService> powerManager =
+      do_GetService(POWERMANAGERSERVICE_CONTRACTID);
+  if (powerManager) {
+    sWakeLockListener = new WakeLockListener();
+    powerManager->AddWakeLockListener(sWakeLockListener);
+  } else {
+    NS_WARNING(
+        "Failed to retrieve PowerManagerService, wakelocks will be broken!");
+  }
+}
+
+static void RemoveScreenWakeLockListener() {
+  nsCOMPtr<nsIPowerManagerService> powerManager =
+      do_GetService(POWERMANAGERSERVICE_CONTRACTID);
+  if (powerManager) {
+    powerManager->RemoveWakeLockListener(sWakeLockListener);
+    sWakeLockListener = nullptr;
+  }
+}
+
+#ifdef MOZ_ENABLE_DBUS
+void nsAppShell::DBusSessionSleepCallback(GDBusProxy* aProxy,
+                                          gchar* aSenderName,
+                                          gchar* aSignalName,
+                                          GVariant* aParameters,
+                                          gpointer aUserData) {
+  if (g_strcmp0(aSignalName, "PrepareForSleep")) {
+    return;
+  }
+  nsCOMPtr<nsIObserverService> observerService =
+      mozilla::services::GetObserverService();
+  if (!observerService) {
+    return;
+  }
+  if (!g_variant_is_of_type(aParameters, G_VARIANT_TYPE_TUPLE) ||
+      g_variant_n_children(aParameters) != 1) {
+    NS_WARNING(
+        nsPrintfCString("Unexpected location updated signal params type: %s\n",
+                        g_variant_get_type_string(aParameters))
+            .get());
+    return;
+  }
+
+  RefPtr<GVariant> variant =
+      dont_AddRef(g_variant_get_child_value(aParameters, 0));
+  if (!g_variant_is_of_type(variant, G_VARIANT_TYPE_BOOLEAN)) {
+    NS_WARNING(
+        nsPrintfCString("Unexpected location updated signal params type: %s\n",
+                        g_variant_get_type_string(aParameters))
+            .get());
+    return;
+  }
+
+  gboolean suspend = g_variant_get_boolean(variant);
+  if (suspend) {
+    // Post sleep_notification
+    observerService->NotifyObservers(nullptr, NS_WIDGET_SLEEP_OBSERVER_TOPIC,
+                                     nullptr);
+  } else {
+    // Post wake_notification
+    observerService->NotifyObservers(nullptr, NS_WIDGET_WAKE_OBSERVER_TOPIC,
+                                     nullptr);
+  }
+}
+
+void nsAppShell::DBusTimedatePropertiesChangedCallback(GDBusProxy* aProxy,
+                                                       gchar* aSenderName,
+                                                       gchar* aSignalName,
+                                                       GVariant* aParameters,
+                                                       gpointer aUserData) {
+  if (g_strcmp0(aSignalName, "PropertiesChanged")) {
+    return;
+  }
+  nsBaseAppShell::OnSystemTimezoneChange();
+}
+
+void nsAppShell::DBusConnectClientResponse(GObject* aObject,
+                                           GAsyncResult* aResult,
+                                           gpointer aUserData) {
+  GUniquePtr<GError> error;
+  RefPtr<GDBusProxy> proxyClient =
+      dont_AddRef(g_dbus_proxy_new_finish(aResult, getter_Transfers(error)));
+  if (!proxyClient) {
+    if (!IsCancelledGError(error.get())) {
+      NS_WARNING(
+          nsPrintfCString("Failed to connect to client: %s\n", error->message)
+              .get());
+    }
+    return;
+  }
+
+  RefPtr self = static_cast<nsAppShell*>(aUserData);
+  if (!strcmp(g_dbus_proxy_get_name(proxyClient), "org.freedesktop.login1")) {
+    self->mLogin1Proxy = std::move(proxyClient);
+    g_signal_connect(self->mLogin1Proxy, "g-signal",
+                     G_CALLBACK(DBusSessionSleepCallback), self);
+  } else {
+    self->mTimedate1Proxy = std::move(proxyClient);
+    g_signal_connect(self->mTimedate1Proxy, "g-signal",
+                     G_CALLBACK(DBusTimedatePropertiesChangedCallback), self);
+  }
+}
+
+// Based on
+// https://github.com/lcp/NetworkManager/blob/240f47c892b4e935a3e92fc09eb15163d1fa28d8/src/nm-sleep-monitor-systemd.c
+// Use login1 to signal sleep and wake notifications.
+void nsAppShell::StartDBusListening() {
+  MOZ_DIAGNOSTIC_ASSERT(!mLogin1Proxy, "Already configured?");
+  MOZ_DIAGNOSTIC_ASSERT(!mTimedate1Proxy, "Already configured?");
+  MOZ_DIAGNOSTIC_ASSERT(!mLogin1ProxyCancellable, "Already configured?");
+  MOZ_DIAGNOSTIC_ASSERT(!mTimedate1ProxyCancellable, "Already configured?");
+
+  mLogin1ProxyCancellable = dont_AddRef(g_cancellable_new());
+  mTimedate1ProxyCancellable = dont_AddRef(g_cancellable_new());
+
+  g_dbus_proxy_new_for_bus(
+      G_BUS_TYPE_SYSTEM, G_DBUS_PROXY_FLAGS_NONE, nullptr,
+      "org.freedesktop.login1", "/org/freedesktop/login1",
+      "org.freedesktop.login1.Manager", mLogin1ProxyCancellable,
+      reinterpret_cast<GAsyncReadyCallback>(DBusConnectClientResponse), this);
+
+  g_dbus_proxy_new_for_bus(
+      G_BUS_TYPE_SYSTEM, G_DBUS_PROXY_FLAGS_NONE, nullptr,
+      "org.freedesktop.timedate1", "/org/freedesktop/timedate1",
+      "org.freedesktop.DBus.Properties", mTimedate1ProxyCancellable,
+      reinterpret_cast<GAsyncReadyCallback>(DBusConnectClientResponse), this);
+}
+
+void nsAppShell::StopDBusListening() {
+  if (mLogin1Proxy) {
+    g_signal_handlers_disconnect_matched(mLogin1Proxy, G_SIGNAL_MATCH_DATA, 0,
+                                         0, nullptr, nullptr, this);
+  }
+  if (mLogin1ProxyCancellable) {
+    g_cancellable_cancel(mLogin1ProxyCancellable);
+    mLogin1ProxyCancellable = nullptr;
+  }
+  mLogin1Proxy = nullptr;
+
+  if (mTimedate1Proxy) {
+    g_signal_handlers_disconnect_matched(mTimedate1Proxy, G_SIGNAL_MATCH_DATA,
+                                         0, 0, nullptr, nullptr, this);
+  }
+  if (mTimedate1ProxyCancellable) {
+    g_cancellable_cancel(mTimedate1ProxyCancellable);
+    mTimedate1ProxyCancellable = nullptr;
+  }
+  mTimedate1Proxy = nullptr;
+}
+#endif
+
+void nsAppShell::TermSignalHandler(int signo) {
+  if (signo != SIGTERM) {
+    NS_WARNING("Wrong signal!");
+    return;
+  }
+  sAppShell->ScheduleQuitEvent();
+}
+
+void nsAppShell::InstallTermSignalHandler() {
+  if (!XRE_IsParentProcess() || PR_GetEnv("MOZ_DISABLE_SIG_HANDLER") ||
+      !sAppShell) {
+    return;
+  }
+
+  struct sigaction act = {}, oldact;
+  act.sa_handler = TermSignalHandler;
+  sigfillset(&act.sa_mask);
+
+  if (NS_WARN_IF(sigaction(SIGTERM, nullptr, &oldact) != 0)) {
+    return;
+  }
+  if (oldact.sa_handler != SIG_DFL) {
+    NS_WARNING("SIGTERM signal handler is already set?");
+  }
+
+  sigaction(SIGTERM, &act, nullptr);
+}
+
+nsresult nsAppShell::Init() {
+  mozilla::hal::Init();
+
+#ifdef MOZ_ENABLE_DBUS
+  if (XRE_IsParentProcess()) {
+    StartDBusListening();
+  }
+#endif
+
+  if (!sPollFunc) {
+    sPollFunc = g_main_context_get_poll_func(nullptr);
+    g_main_context_set_poll_func(nullptr, &PollWrapper);
+  }
+
+  if (XRE_IsParentProcess()) {
+    ScreenManager& screenManager = ScreenManager::GetSingleton();
+    if (gfxPlatform::IsHeadless()) {
+      screenManager.SetHelper(mozilla::MakeUnique<HeadlessScreenHelper>());
+    } else {
+      screenManager.SetHelper(mozilla::MakeUnique<ScreenHelperGTK>());
+    }
+
+    if (gtk_check_version(3, 16, 3) == nullptr) {
+      // Before 3.16.3, GDK cannot override classname by --class command line
+      // option when program uses gdk_set_program_class().
+      //
+      // See https://bugzilla.gnome.org/show_bug.cgi?id=747634
+      //
+      // Only bother doing this for the parent process, since it's the one
+      // creating top-level windows.
+      if (gAppData) {
+        gdk_set_program_class(gAppData->remotingName);
+      }
+    }
+  }
+
+  if (!sPendingResumeQuark &&
+      gtk_check_version(3, 14, 7) != nullptr) {  // GTK 3.0 to GTK 3.14.7.
+    // GTK 3.8 - 3.14 registered this type when creating the frame clock
+    // for the root window of the display when the display was opened.
+    GType gdkFrameClockIdleType = g_type_from_name("GdkFrameClockIdle");
+    if (gdkFrameClockIdleType) {  // not in versions prior to 3.8
+      sPendingResumeQuark = g_quark_from_string("moz-resume-is-pending");
+      auto gdk_frame_clock_idle_class =
+          G_OBJECT_CLASS(g_type_class_peek_static(gdkFrameClockIdleType));
+      auto constructed = &gdk_frame_clock_idle_class->constructed;
+      sRealGdkFrameClockConstructed = *constructed;
+      *constructed = WrapGdkFrameClockConstructed;
+      auto dispose = &gdk_frame_clock_idle_class->dispose;
+      sRealGdkFrameClockDispose = *dispose;
+      *dispose = WrapGdkFrameClockDispose;
+    }
+  }
+
+  // Workaround for bug 1209659 which is fixed by Gtk3.20
+  if (gtk_check_version(3, 20, 0) != nullptr) {
+    unsetenv("GTK_CSD");
+  }
+
+  // Whitelist of only common, stable formats - see bugs 1197059 and 1203078
+  GSList* pixbufFormats = gdk_pixbuf_get_formats();
+  for (GSList* iter = pixbufFormats; iter; iter = iter->next) {
+    GdkPixbufFormat* format = static_cast<GdkPixbufFormat*>(iter->data);
+    gchar* name = gdk_pixbuf_format_get_name(format);
+    if (strcmp(name, "jpeg") && strcmp(name, "png") && strcmp(name, "gif") &&
+        strcmp(name, "bmp") && strcmp(name, "ico") && strcmp(name, "xpm") &&
+        strcmp(name, "svg") && strcmp(name, "webp") && strcmp(name, "avif")) {
+      gdk_pixbuf_format_set_disabled(format, TRUE);
+    }
+    g_free(name);
+  }
+  g_slist_free(pixbufFormats);
+
+  int err = pipe(mPipeFDs);
+  if (err) return NS_ERROR_OUT_OF_MEMORY;
+
+  GIOChannel* ioc;
+  GSource* source;
+
+  // make the pipe nonblocking
+
+  int flags = fcntl(mPipeFDs[0], F_GETFL, 0);
+  if (flags == -1) goto failed;
+  err = fcntl(mPipeFDs[0], F_SETFL, flags | O_NONBLOCK);
+  if (err == -1) goto failed;
+  flags = fcntl(mPipeFDs[1], F_GETFL, 0);
+  if (flags == -1) goto failed;
+  err = fcntl(mPipeFDs[1], F_SETFL, flags | O_NONBLOCK);
+  if (err == -1) goto failed;
+
+  ioc = g_io_channel_unix_new(mPipeFDs[0]);
+  source = g_io_create_watch(ioc, G_IO_IN);
+  g_io_channel_unref(ioc);
+  g_source_set_callback(source, (GSourceFunc)EventProcessorCallback, this,
+                        nullptr);
+  g_source_set_can_recurse(source, TRUE);
+  mTag = g_source_attach(source, nullptr);
+  g_source_unref(source);
+
+  sAppShell = this;
+
+  return nsBaseAppShell::Init();
+failed:
+  close(mPipeFDs[0]);
+  close(mPipeFDs[1]);
+  mPipeFDs[0] = mPipeFDs[1] = 0;
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP nsAppShell::Run() {
+  if (XRE_IsParentProcess()) {
+    AddScreenWakeLockListener();
+  }
+
+  nsresult rv = nsBaseAppShell::Run();
+
+  if (XRE_IsParentProcess()) {
+    RemoveScreenWakeLockListener();
+  }
+  return rv;
+}
+
+void nsAppShell::ScheduleNativeEventCallback() {
+  unsigned char buf[] = {NOTIFY_TOKEN};
+  Unused << write(mPipeFDs[1], buf, 1);
+}
+
+void nsAppShell::ScheduleQuitEvent() {
+  unsigned char buf[] = {QUIT_TOKEN};
+  Unused << write(mPipeFDs[1], buf, 1);
+}
+
+bool nsAppShell::ProcessNextNativeEvent(bool mayWait) {
+  if (mSuspendNativeCount) {
+    return false;
+  }
+  bool didProcessEvent = g_main_context_iteration(nullptr, mayWait);
+  return didProcessEvent;
+}
diff --git a/widget/gtk/nsAppShell.h b/widget/gtk/nsAppShell.h
new file mode 100644
index 0000000000..0b628033cc
--- /dev/null
+++ b/widget/gtk/nsAppShell.h
@@ -0,0 +1,69 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsAppShell_h__
+#define nsAppShell_h__
+
+#ifdef MOZ_ENABLE_DBUS
+#  include <gio/gio.h>
+#  include "mozilla/RefPtr.h"
+#  include "mozilla/GRefPtr.h"
+#endif
+#include <glib.h>
+#include "nsBaseAppShell.h"
+
+class nsAppShell : public nsBaseAppShell {
+ public:
+  nsAppShell() = default;
+
+  // nsBaseAppShell overrides:
+  nsresult Init();
+  NS_IMETHOD Run() override;
+
+  void ScheduleNativeEventCallback() override;
+  bool ProcessNextNativeEvent(bool mayWait) override;
+
+#ifdef MOZ_ENABLE_DBUS
+  void StartDBusListening();
+  void StopDBusListening();
+
+  static void DBusSessionSleepCallback(GDBusProxy* aProxy, gchar* aSenderName,
+                                       gchar* aSignalName,
+                                       GVariant* aParameters,
+                                       gpointer aUserData);
+  static void DBusTimedatePropertiesChangedCallback(GDBusProxy* aProxy,
+                                                    gchar* aSenderName,
+                                                    gchar* aSignalName,
+                                                    GVariant* aParameters,
+                                                    gpointer aUserData);
+  static void DBusConnectClientResponse(GObject* aObject, GAsyncResult* aResult,
+                                        gpointer aUserData);
+#endif
+
+  static void InstallTermSignalHandler();
+
+ private:
+  virtual ~nsAppShell();
+
+  static gboolean EventProcessorCallback(GIOChannel* source,
+                                         GIOCondition condition, gpointer data);
+  static void TermSignalHandler(int signo);
+
+  void ScheduleQuitEvent();
+
+  int mPipeFDs[2] = {0, 0};
+  unsigned mTag = 0;
+
+#ifdef MOZ_ENABLE_DBUS
+  RefPtr<GDBusProxy> mLogin1Proxy;
+  RefPtr<GCancellable> mLogin1ProxyCancellable;
+  RefPtr<GDBusProxy> mTimedate1Proxy;
+  RefPtr<GCancellable> mTimedate1ProxyCancellable;
+#endif
+};
+
+#endif /* nsAppShell_h__ */
diff --git a/widget/gtk/nsApplicationChooser.cpp b/widget/gtk/nsApplicationChooser.cpp
new file mode 100644
index 0000000000..6752c52caf
--- /dev/null
+++ b/widget/gtk/nsApplicationChooser.cpp
@@ -0,0 +1,132 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Types.h"
+
+#include <gtk/gtk.h>
+
+#include "nsApplicationChooser.h"
+#include "WidgetUtils.h"
+#include "nsIMIMEInfo.h"
+#include "nsIWidget.h"
+#include "nsIFile.h"
+#include "nsCExternalHandlerService.h"
+#include "nsComponentManagerUtils.h"
+#include "nsGtkUtils.h"
+#include "nsPIDOMWindow.h"
+
+using namespace mozilla;
+
+NS_IMPL_ISUPPORTS(nsApplicationChooser, nsIApplicationChooser)
+
+nsApplicationChooser::nsApplicationChooser() = default;
+
+nsApplicationChooser::~nsApplicationChooser() = default;
+
+NS_IMETHODIMP
+nsApplicationChooser::Init(mozIDOMWindowProxy* aParent,
+                           const nsACString& aTitle) {
+  NS_ENSURE_TRUE(aParent, NS_ERROR_FAILURE);
+  auto* parent = nsPIDOMWindowOuter::From(aParent);
+  mParentWidget = widget::WidgetUtils::DOMWindowToWidget(parent);
+  mWindowTitle.Assign(aTitle);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsApplicationChooser::Open(const nsACString& aContentType,
+                           nsIApplicationChooserFinishedCallback* aCallback) {
+  MOZ_ASSERT(aCallback);
+  if (mCallback) {
+    NS_WARNING("Chooser is already in progress.");
+    return NS_ERROR_ALREADY_INITIALIZED;
+  }
+  mCallback = aCallback;
+  NS_ENSURE_TRUE(mParentWidget, NS_ERROR_FAILURE);
+  GtkWindow* parent_widget =
+      GTK_WINDOW(mParentWidget->GetNativeData(NS_NATIVE_SHELLWIDGET));
+
+  GtkWidget* chooser = gtk_app_chooser_dialog_new_for_content_type(
+      parent_widget,
+      (GtkDialogFlags)(GTK_DIALOG_MODAL | GTK_DIALOG_DESTROY_WITH_PARENT),
+      PromiseFlatCString(aContentType).get());
+  gtk_app_chooser_dialog_set_heading(GTK_APP_CHOOSER_DIALOG(chooser),
+                                     mWindowTitle.BeginReading());
+  NS_ADDREF_THIS();
+  g_signal_connect(chooser, "response", G_CALLBACK(OnResponse), this);
+  g_signal_connect(chooser, "destroy", G_CALLBACK(OnDestroy), this);
+  gtk_widget_show(chooser);
+  return NS_OK;
+}
+
+/* static */
+void nsApplicationChooser::OnResponse(GtkWidget* chooser, gint response_id,
+                                      gpointer user_data) {
+  static_cast<nsApplicationChooser*>(user_data)->Done(chooser, response_id);
+}
+
+/* static */
+void nsApplicationChooser::OnDestroy(GtkWidget* chooser, gpointer user_data) {
+  static_cast<nsApplicationChooser*>(user_data)->Done(chooser,
+                                                      GTK_RESPONSE_CANCEL);
+}
+
+void nsApplicationChooser::Done(GtkWidget* chooser, gint response) {
+  nsCOMPtr<nsILocalHandlerApp> localHandler;
+  nsresult rv;
+  switch (response) {
+    case GTK_RESPONSE_OK:
+    case GTK_RESPONSE_ACCEPT: {
+      localHandler = do_CreateInstance(NS_LOCALHANDLERAPP_CONTRACTID, &rv);
+      if (NS_FAILED(rv)) {
+        NS_WARNING("Out of memory.");
+        break;
+      }
+      GAppInfo* app_info =
+          gtk_app_chooser_get_app_info(GTK_APP_CHOOSER(chooser));
+
+      nsCOMPtr<nsIFile> localExecutable;
+      gchar* fileWithFullPath =
+          g_find_program_in_path(g_app_info_get_executable(app_info));
+      if (!fileWithFullPath) {
+        g_object_unref(app_info);
+        NS_WARNING("Cannot find program in path.");
+        break;
+      }
+      rv = NS_NewNativeLocalFile(nsDependentCString(fileWithFullPath), false,
+                                 getter_AddRefs(localExecutable));
+      g_free(fileWithFullPath);
+      if (NS_FAILED(rv)) {
+        NS_WARNING("Cannot create local filename.");
+        localHandler = nullptr;
+      } else {
+        localHandler->SetExecutable(localExecutable);
+        localHandler->SetName(
+            NS_ConvertUTF8toUTF16(g_app_info_get_display_name(app_info)));
+      }
+      g_object_unref(app_info);
+    }
+
+    break;
+    case GTK_RESPONSE_CANCEL:
+    case GTK_RESPONSE_CLOSE:
+    case GTK_RESPONSE_DELETE_EVENT:
+      break;
+    default:
+      NS_WARNING("Unexpected response");
+      break;
+  }
+
+  // A "response" signal won't be sent again but "destroy" will be.
+  g_signal_handlers_disconnect_by_func(chooser, FuncToGpointer(OnDestroy),
+                                       this);
+  gtk_widget_destroy(chooser);
+
+  if (mCallback) {
+    mCallback->Done(localHandler);
+    mCallback = nullptr;
+  }
+  NS_RELEASE_THIS();
+}
diff --git a/widget/gtk/nsApplicationChooser.h b/widget/gtk/nsApplicationChooser.h
new file mode 100644
index 0000000000..22f9a808c0
--- /dev/null
+++ b/widget/gtk/nsApplicationChooser.h
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsApplicationChooser_h__
+#define nsApplicationChooser_h__
+
+#include <gtk/gtk.h>
+#include "nsCOMPtr.h"
+#include "nsIApplicationChooser.h"
+#include "nsString.h"
+
+class nsIWidget;
+
+class nsApplicationChooser final : public nsIApplicationChooser {
+ public:
+  nsApplicationChooser();
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIAPPLICATIONCHOOSER
+  void Done(GtkWidget* chooser, gint response);
+
+ private:
+  ~nsApplicationChooser();
+  nsCOMPtr<nsIWidget> mParentWidget;
+  nsCString mWindowTitle;
+  nsCOMPtr<nsIApplicationChooserFinishedCallback> mCallback;
+  static void OnResponse(GtkWidget* chooser, gint response_id,
+                         gpointer user_data);
+  static void OnDestroy(GtkWidget* chooser, gpointer user_data);
+};
+#endif
diff --git a/widget/gtk/nsBidiKeyboard.cpp b/widget/gtk/nsBidiKeyboard.cpp
new file mode 100644
index 0000000000..a57235195b
--- /dev/null
+++ b/widget/gtk/nsBidiKeyboard.cpp
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "prlink.h"
+
+#include "nsBidiKeyboard.h"
+#include "nsIWidget.h"
+#include <gtk/gtk.h>
+
+NS_IMPL_ISUPPORTS(nsBidiKeyboard, nsIBidiKeyboard)
+
+nsBidiKeyboard::nsBidiKeyboard() { Reset(); }
+
+NS_IMETHODIMP
+nsBidiKeyboard::Reset() {
+  // NB: The default keymap can be null (e.g. in xpcshell). In that case,
+  // simply assume that we don't have bidi keyboards.
+  mHaveBidiKeyboards = false;
+
+  GdkDisplay* display = gdk_display_get_default();
+  if (!display) return NS_OK;
+
+  GdkKeymap* keymap = gdk_keymap_get_for_display(display);
+  mHaveBidiKeyboards = keymap && gdk_keymap_have_bidi_layouts(keymap);
+  return NS_OK;
+}
+
+nsBidiKeyboard::~nsBidiKeyboard() = default;
+
+NS_IMETHODIMP
+nsBidiKeyboard::IsLangRTL(bool* aIsRTL) {
+  if (!mHaveBidiKeyboards) return NS_ERROR_FAILURE;
+
+  *aIsRTL = (gdk_keymap_get_direction(gdk_keymap_get_default()) ==
+             PANGO_DIRECTION_RTL);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBidiKeyboard::GetHaveBidiKeyboards(bool* aResult) {
+  // not implemented yet
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+// static
+already_AddRefed<nsIBidiKeyboard> nsIWidget::CreateBidiKeyboardInner() {
+  return do_AddRef(new nsBidiKeyboard());
+}
diff --git a/widget/gtk/nsBidiKeyboard.h b/widget/gtk/nsBidiKeyboard.h
new file mode 100644
index 0000000000..1bc1c7e0a2
--- /dev/null
+++ b/widget/gtk/nsBidiKeyboard.h
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsBidiKeyboard
+#define __nsBidiKeyboard
+#include "nsIBidiKeyboard.h"
+
+class nsBidiKeyboard : public nsIBidiKeyboard {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIBIDIKEYBOARD
+
+  nsBidiKeyboard();
+
+ protected:
+  virtual ~nsBidiKeyboard();
+
+  bool mHaveBidiKeyboards;
+};
+
+#endif  // __nsBidiKeyboard
diff --git a/widget/gtk/nsClipboard.cpp b/widget/gtk/nsClipboard.cpp
new file mode 100644
index 0000000000..571b43f1cc
--- /dev/null
+++ b/widget/gtk/nsClipboard.cpp
@@ -0,0 +1,1425 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+
+#include "nsArrayUtils.h"
+#include "nsClipboard.h"
+#if defined(MOZ_X11)
+#  include "nsClipboardX11.h"
+#endif
+#if defined(MOZ_WAYLAND)
+#  include "nsClipboardWayland.h"
+#  include "nsWaylandDisplay.h"
+#endif
+#include "nsGtkUtils.h"
+#include "nsIURI.h"
+#include "nsIFile.h"
+#include "nsNetUtil.h"
+#include "nsContentUtils.h"
+#include "HeadlessClipboard.h"
+#include "nsSupportsPrimitives.h"
+#include "nsString.h"
+#include "nsReadableUtils.h"
+#include "nsPrimitiveHelpers.h"
+#include "nsImageToPixbuf.h"
+#include "nsStringStream.h"
+#include "nsIFileURL.h"
+#include "nsIObserverService.h"
+#include "mozilla/Services.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/GRefPtr.h"
+#include "mozilla/SchedulerGroup.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/TimeStamp.h"
+#include "GRefPtr.h"
+#include "WidgetUtilsGtk.h"
+
+#include "imgIContainer.h"
+
+#include <gtk/gtk.h>
+#if defined(MOZ_X11)
+#  include <gtk/gtkx.h>
+#endif
+
+#include "mozilla/Encoding.h"
+
+using namespace mozilla;
+
+// Idle timeout for receiving selection and property notify events (microsec)
+// Right now it's set to 1 sec.
+const int kClipboardTimeout = 1000000;
+
+// Defines how many event loop iterations will be done without sleep.
+// We ususally get data in first 2-3 iterations unless some large object
+// (an image for instance) is transferred through clipboard.
+const int kClipboardFastIterationNum = 3;
+
+// We add this prefix to HTML markup, so that GetHTMLCharset can correctly
+// detect the HTML as UTF-8 encoded.
+static const char kHTMLMarkupPrefix[] =
+    R"(<meta http-equiv="content-type" content="text/html; charset=utf-8">)";
+
+static const char kURIListMime[] = "text/uri-list";
+
+ClipboardTargets nsRetrievalContext::sClipboardTargets;
+ClipboardTargets nsRetrievalContext::sPrimaryTargets;
+
+// Callback when someone asks us for the data
+static void clipboard_get_cb(GtkClipboard* aGtkClipboard,
+                             GtkSelectionData* aSelectionData, guint info,
+                             gpointer user_data);
+
+// Callback when someone asks us to clear a clipboard
+static void clipboard_clear_cb(GtkClipboard* aGtkClipboard, gpointer user_data);
+
+// Callback when owner of clipboard data is changed
+static void clipboard_owner_change_cb(GtkClipboard* aGtkClipboard,
+                                      GdkEventOwnerChange* aEvent,
+                                      gpointer aUserData);
+
+static bool GetHTMLCharset(Span<const char> aData, nsCString& str);
+
+static void SetTransferableData(nsITransferable* aTransferable,
+                                const nsACString& aFlavor,
+                                const char* aClipboardData,
+                                uint32_t aClipboardDataLength) {
+  LOGCLIP("SetTransferableData MIME %s\n", PromiseFlatCString(aFlavor).get());
+  nsCOMPtr<nsISupports> wrapper;
+  nsPrimitiveHelpers::CreatePrimitiveForData(
+      aFlavor, aClipboardData, aClipboardDataLength, getter_AddRefs(wrapper));
+  aTransferable->SetTransferData(PromiseFlatCString(aFlavor).get(), wrapper);
+}
+
+ClipboardTargets ClipboardTargets::Clone() {
+  ClipboardTargets ret;
+  ret.mCount = mCount;
+  if (mCount) {
+    ret.mTargets.reset(
+        reinterpret_cast<GdkAtom*>(g_malloc(sizeof(GdkAtom) * mCount)));
+    memcpy(ret.mTargets.get(), mTargets.get(), sizeof(GdkAtom) * mCount);
+  }
+  return ret;
+}
+
+void ClipboardTargets::Set(ClipboardTargets aTargets) {
+  mCount = aTargets.mCount;
+  mTargets = std::move(aTargets.mTargets);
+}
+
+void ClipboardData::SetData(Span<const uint8_t> aData) {
+  mData = nullptr;
+  mLength = aData.Length();
+  if (mLength) {
+    mData.reset(reinterpret_cast<char*>(g_malloc(sizeof(char) * mLength)));
+    memcpy(mData.get(), aData.data(), sizeof(char) * mLength);
+  }
+}
+
+void ClipboardData::SetText(Span<const char> aData) {
+  mData = nullptr;
+  mLength = aData.Length();
+  if (mLength) {
+    mData.reset(
+        reinterpret_cast<char*>(g_malloc(sizeof(char) * (mLength + 1))));
+    memcpy(mData.get(), aData.data(), sizeof(char) * mLength);
+    mData.get()[mLength] = '\0';
+  }
+}
+
+void ClipboardData::SetTargets(ClipboardTargets aTargets) {
+  mLength = aTargets.mCount;
+  mData.reset(reinterpret_cast<char*>(aTargets.mTargets.release()));
+}
+
+ClipboardTargets ClipboardData::ExtractTargets() {
+  GUniquePtr<GdkAtom> targets(reinterpret_cast<GdkAtom*>(mData.release()));
+  uint32_t length = std::exchange(mLength, 0);
+  return ClipboardTargets{std::move(targets), length};
+}
+
+GdkAtom GetSelectionAtom(int32_t aWhichClipboard) {
+  if (aWhichClipboard == nsIClipboard::kGlobalClipboard)
+    return GDK_SELECTION_CLIPBOARD;
+
+  return GDK_SELECTION_PRIMARY;
+}
+
+int GetGeckoClipboardType(GtkClipboard* aGtkClipboard) {
+  if (aGtkClipboard == gtk_clipboard_get(GDK_SELECTION_PRIMARY))
+    return nsClipboard::kSelectionClipboard;
+  else if (aGtkClipboard == gtk_clipboard_get(GDK_SELECTION_CLIPBOARD))
+    return nsClipboard::kGlobalClipboard;
+
+  return -1;  // THAT AIN'T NO CLIPBOARD I EVER HEARD OF
+}
+
+void nsRetrievalContext::ClearCachedTargetsClipboard(GtkClipboard* aClipboard,
+                                                     GdkEvent* aEvent,
+                                                     gpointer data) {
+  LOGCLIP("nsRetrievalContext::ClearCachedTargetsClipboard()");
+  sClipboardTargets.Clear();
+}
+
+void nsRetrievalContext::ClearCachedTargetsPrimary(GtkClipboard* aClipboard,
+                                                   GdkEvent* aEvent,
+                                                   gpointer data) {
+  LOGCLIP("nsRetrievalContext::ClearCachedTargetsPrimary()");
+  sPrimaryTargets.Clear();
+}
+
+ClipboardTargets nsRetrievalContext::GetTargets(int32_t aWhichClipboard) {
+  LOGCLIP("nsRetrievalContext::GetTargets(%s)\n",
+          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                              : "clipboard");
+  ClipboardTargets& storedTargets =
+      (aWhichClipboard == nsClipboard::kSelectionClipboard) ? sPrimaryTargets
+                                                            : sClipboardTargets;
+  if (!storedTargets) {
+    LOGCLIP("  getting targets from system");
+    storedTargets.Set(GetTargetsImpl(aWhichClipboard));
+  } else {
+    LOGCLIP("  using cached targets");
+  }
+  return storedTargets.Clone();
+}
+
+nsRetrievalContext::~nsRetrievalContext() {
+  sClipboardTargets.Clear();
+  sPrimaryTargets.Clear();
+}
+
+nsClipboard::nsClipboard()
+    : nsBaseClipboard(mozilla::dom::ClipboardCapabilities(
+#ifdef MOZ_WAYLAND
+          widget::GdkIsWaylandDisplay()
+              ? widget::WaylandDisplayGet()->IsPrimarySelectionEnabled()
+              : true,
+#else
+          true, /* supportsSelectionClipboard */
+#endif
+          false /* supportsFindClipboard */,
+          false /* supportsSelectionCache */)) {
+  g_signal_connect(gtk_clipboard_get(GDK_SELECTION_CLIPBOARD), "owner-change",
+                   G_CALLBACK(clipboard_owner_change_cb), this);
+  g_signal_connect(gtk_clipboard_get(GDK_SELECTION_PRIMARY), "owner-change",
+                   G_CALLBACK(clipboard_owner_change_cb), this);
+}
+
+nsClipboard::~nsClipboard() {
+  g_signal_handlers_disconnect_by_func(
+      gtk_clipboard_get(GDK_SELECTION_CLIPBOARD),
+      FuncToGpointer(clipboard_owner_change_cb), this);
+  g_signal_handlers_disconnect_by_func(
+      gtk_clipboard_get(GDK_SELECTION_PRIMARY),
+      FuncToGpointer(clipboard_owner_change_cb), this);
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(nsClipboard, nsBaseClipboard, nsIObserver)
+
+nsresult nsClipboard::Init(void) {
+#if defined(MOZ_X11)
+  if (widget::GdkIsX11Display()) {
+    mContext = new nsRetrievalContextX11();
+  }
+#endif
+#if defined(MOZ_WAYLAND)
+  if (widget::GdkIsWaylandDisplay()) {
+    mContext = new nsRetrievalContextWayland();
+  }
+#endif
+
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (os) {
+    os->AddObserver(this, "xpcom-shutdown", false);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsClipboard::Observe(nsISupports* aSubject, const char* aTopic,
+                     const char16_t* aData) {
+  // Save global clipboard content to CLIPBOARD_MANAGER.
+  // gtk_clipboard_store() can run an event loop, so call from a dedicated
+  // runnable.
+  return SchedulerGroup::Dispatch(
+      NS_NewRunnableFunction("gtk_clipboard_store()", []() {
+        LOGCLIP("nsClipboard storing clipboard content\n");
+        gtk_clipboard_store(gtk_clipboard_get(GDK_SELECTION_CLIPBOARD));
+      }));
+}
+
+NS_IMETHODIMP
+nsClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  // See if we can short cut
+  if ((aWhichClipboard == kGlobalClipboard &&
+       aTransferable == mGlobalTransferable.get()) ||
+      (aWhichClipboard == kSelectionClipboard &&
+       aTransferable == mSelectionTransferable.get())) {
+    return NS_OK;
+  }
+
+  LOGCLIP("nsClipboard::SetNativeClipboardData (%s)\n",
+          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+
+  // List of suported targets
+  GtkTargetList* list = gtk_target_list_new(nullptr, 0);
+
+  // Get the types of supported flavors
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanExport(flavors);
+  if (NS_FAILED(rv)) {
+    LOGCLIP("    FlavorsTransferableCanExport failed!\n");
+    // Fall through.  |gtkTargets| will be null below.
+  }
+
+  // Add all the flavors to this widget's supported type.
+  bool imagesAdded = false;
+  for (uint32_t i = 0; i < flavors.Length(); i++) {
+    nsCString& flavorStr = flavors[i];
+    LOGCLIP("    processing target %s\n", flavorStr.get());
+
+    // Special case text/plain since we can handle all of the string types.
+    if (flavorStr.EqualsLiteral(kTextMime)) {
+      LOGCLIP("    adding TEXT targets\n");
+      gtk_target_list_add_text_targets(list, 0);
+      continue;
+    }
+
+    if (nsContentUtils::IsFlavorImage(flavorStr)) {
+      // Don't bother adding image targets twice
+      if (!imagesAdded) {
+        // accept any writable image type
+        LOGCLIP("    adding IMAGE targets\n");
+        gtk_target_list_add_image_targets(list, 0, TRUE);
+        imagesAdded = true;
+      }
+      continue;
+    }
+
+    if (flavorStr.EqualsLiteral(kFileMime)) {
+      LOGCLIP("    adding text/uri-list target\n");
+      GdkAtom atom = gdk_atom_intern(kURIListMime, FALSE);
+      gtk_target_list_add(list, atom, 0, 0);
+      continue;
+    }
+
+    // Add this to our list of valid targets
+    LOGCLIP("    adding OTHER target %s\n", flavorStr.get());
+    GdkAtom atom = gdk_atom_intern(flavorStr.get(), FALSE);
+    gtk_target_list_add(list, atom, 0, 0);
+  }
+
+  // Get GTK clipboard (CLIPBOARD or PRIMARY)
+  GtkClipboard* gtkClipboard =
+      gtk_clipboard_get(GetSelectionAtom(aWhichClipboard));
+
+  gint numTargets = 0;
+  GtkTargetEntry* gtkTargets =
+      gtk_target_table_new_from_list(list, &numTargets);
+  if (!gtkTargets || numTargets == 0) {
+    LOGCLIP(
+        "    gtk_target_table_new_from_list() failed or empty list of "
+        "targets!\n");
+    // Clear references to the any old data and let GTK know that it is no
+    // longer available.
+    EmptyNativeClipboardData(aWhichClipboard);
+    return NS_ERROR_FAILURE;
+  }
+
+  ClearCachedTargets(aWhichClipboard);
+
+  // Set getcallback and request to store data after an application exit
+  if (gtk_clipboard_set_with_data(gtkClipboard, gtkTargets, numTargets,
+                                  clipboard_get_cb, clipboard_clear_cb, this)) {
+    // We managed to set-up the clipboard so update internal state
+    // We have to set it now because gtk_clipboard_set_with_data() calls
+    // clipboard_clear_cb() which reset our internal state
+    if (aWhichClipboard == kSelectionClipboard) {
+      mSelectionSequenceNumber++;
+      mSelectionTransferable = aTransferable;
+    } else {
+      mGlobalSequenceNumber++;
+      mGlobalTransferable = aTransferable;
+      gtk_clipboard_set_can_store(gtkClipboard, gtkTargets, numTargets);
+    }
+
+    rv = NS_OK;
+  } else {
+    LOGCLIP("    gtk_clipboard_set_with_data() failed!\n");
+    EmptyNativeClipboardData(aWhichClipboard);
+    rv = NS_ERROR_FAILURE;
+  }
+
+  gtk_target_table_free(gtkTargets, numTargets);
+  gtk_target_list_unref(list);
+
+  return rv;
+}
+
+mozilla::Result<int32_t, nsresult>
+nsClipboard::GetNativeClipboardSequenceNumber(int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+  return aWhichClipboard == kSelectionClipboard ? mSelectionSequenceNumber
+                                                : mGlobalSequenceNumber;
+}
+
+static bool IsMIMEAtFlavourList(const nsTArray<nsCString>& aFlavourList,
+                                const char* aMime) {
+  for (const auto& flavorStr : aFlavourList) {
+    if (flavorStr.Equals(aMime)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+// When clipboard contains only images, X11/Gtk tries to convert them
+// to text when we request text instead of just fail to provide the data.
+// So if clipboard contains images only remove text MIME offer.
+bool nsClipboard::FilterImportedFlavors(int32_t aWhichClipboard,
+                                        nsTArray<nsCString>& aFlavors) {
+  LOGCLIP("nsClipboard::FilterImportedFlavors");
+
+  auto targets = mContext->GetTargets(aWhichClipboard);
+  if (!targets) {
+    LOGCLIP("    X11: no targes at clipboard (null), quit.\n");
+    return true;
+  }
+
+  for (const auto& atom : targets.AsSpan()) {
+    GUniquePtr<gchar> atom_name(gdk_atom_name(atom));
+    if (!atom_name) {
+      continue;
+    }
+    // Filter out system MIME types.
+    if (strcmp(atom_name.get(), "TARGETS") == 0 ||
+        strcmp(atom_name.get(), "TIMESTAMP") == 0 ||
+        strcmp(atom_name.get(), "SAVE_TARGETS") == 0 ||
+        strcmp(atom_name.get(), "MULTIPLE") == 0) {
+      continue;
+    }
+    // Filter out types which can't be converted to text.
+    if (strncmp(atom_name.get(), "image/", 6) == 0 ||
+        strncmp(atom_name.get(), "application/", 12) == 0 ||
+        strncmp(atom_name.get(), "audio/", 6) == 0 ||
+        strncmp(atom_name.get(), "video/", 6) == 0) {
+      continue;
+    }
+    // We have some other MIME type on clipboard which can be hopefully
+    // converted to text without any problem.
+    LOGCLIP("    X11: text types in clipboard, no need to filter them.\n");
+    return true;
+  }
+
+  // So make sure we offer only types we have at clipboard.
+  nsTArray<nsCString> clipboardFlavors;
+  for (const auto& atom : targets.AsSpan()) {
+    GUniquePtr<gchar> atom_name(gdk_atom_name(atom));
+    if (!atom_name) {
+      continue;
+    }
+    if (IsMIMEAtFlavourList(aFlavors, atom_name.get())) {
+      clipboardFlavors.AppendElement(nsCString(atom_name.get()));
+    }
+  }
+  aFlavors.SwapElements(clipboardFlavors);
+#ifdef MOZ_LOGGING
+  LOGCLIP("    X11: Flavors which match clipboard content:\n");
+  for (uint32_t i = 0; i < aFlavors.Length(); i++) {
+    LOGCLIP("    %s\n", aFlavors[i].get());
+  }
+#endif
+  return true;
+}
+
+static nsresult GetTransferableFlavors(nsITransferable* aTransferable,
+                                       nsTArray<nsCString>& aFlavors) {
+  if (!aTransferable) {
+    return NS_ERROR_FAILURE;
+  }
+  // Get a list of flavors this transferable can import
+  nsresult rv = aTransferable->FlavorsTransferableCanImport(aFlavors);
+  if (NS_FAILED(rv)) {
+    LOGCLIP("  FlavorsTransferableCanImport falied!\n");
+    return rv;
+  }
+#ifdef MOZ_LOGGING
+  LOGCLIP("  Flavors which can be imported:");
+  for (const auto& flavor : aFlavors) {
+    LOGCLIP("    %s", flavor.get());
+  }
+#endif
+  return NS_OK;
+}
+
+static bool TransferableSetFile(nsITransferable* aTransferable,
+                                const nsACString& aURIList) {
+  nsresult rv;
+  nsTArray<nsCString> uris = mozilla::widget::ParseTextURIList(aURIList);
+  if (!uris.IsEmpty()) {
+    nsCOMPtr<nsIURI> fileURI;
+    NS_NewURI(getter_AddRefs(fileURI), uris[0]);
+    if (nsCOMPtr<nsIFileURL> fileURL = do_QueryInterface(fileURI, &rv)) {
+      nsCOMPtr<nsIFile> file;
+      rv = fileURL->GetFile(getter_AddRefs(file));
+      if (NS_SUCCEEDED(rv)) {
+        aTransferable->SetTransferData(kFileMime, file);
+        LOGCLIP("  successfully set file to clipboard\n");
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+static bool TransferableSetHTML(nsITransferable* aTransferable,
+                                Span<const char> aData) {
+  nsLiteralCString mimeType(kHTMLMime);
+
+  // Convert text/html into our text format
+  nsAutoCString charset;
+  if (!GetHTMLCharset(aData, charset)) {
+    // Fall back to utf-8 in case html/data is missing kHTMLMarkupPrefix.
+    LOGCLIP("Failed to get html/text encoding, fall back to utf-8.\n");
+    charset.AssignLiteral("utf-8");
+  }
+
+  LOGCLIP("TransferableSetHTML: HTML detected charset %s", charset.get());
+  // app which use "text/html" to copy&paste
+  // get the decoder
+  auto encoding = Encoding::ForLabelNoReplacement(charset);
+  if (!encoding) {
+    LOGCLIP("TransferableSetHTML: get unicode decoder error (charset: %s)",
+            charset.get());
+    return false;
+  }
+
+  // According to spec html UTF-16BE/LE should be switched to UTF-8
+  // https://html.spec.whatwg.org/#determining-the-character-encoding:utf-16-encoding-2
+  if (encoding == UTF_16LE_ENCODING || encoding == UTF_16BE_ENCODING) {
+    encoding = UTF_8_ENCODING;
+  }
+
+  // Remove kHTMLMarkupPrefix again, it won't necessarily cause any
+  // issues, but might confuse other users.
+  const size_t prefixLen = ArrayLength(kHTMLMarkupPrefix) - 1;
+  if (aData.Length() >= prefixLen && nsDependentCSubstring(aData.To(prefixLen))
+                                         .EqualsLiteral(kHTMLMarkupPrefix)) {
+    aData = aData.From(prefixLen);
+  }
+
+  nsAutoString unicodeData;
+  auto [rv, enc] = encoding->Decode(AsBytes(aData), unicodeData);
+#if MOZ_LOGGING
+  if (enc != UTF_8_ENCODING &&
+      MOZ_LOG_TEST(gClipboardLog, mozilla::LogLevel::Debug)) {
+    nsCString decoderName;
+    enc->Name(decoderName);
+    LOGCLIP("TransferableSetHTML: expected UTF-8 decoder but got %s",
+            decoderName.get());
+  }
+#endif
+  if (NS_FAILED(rv)) {
+    LOGCLIP("TransferableSetHTML: failed to decode HTML");
+    return false;
+  }
+  SetTransferableData(aTransferable, mimeType,
+                      (const char*)unicodeData.BeginReading(),
+                      unicodeData.Length() * sizeof(char16_t));
+  return true;
+}
+
+NS_IMETHODIMP
+nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  LOGCLIP("nsClipboard::GetNativeClipboardData (%s)\n",
+          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+
+  // TODO: Ensure we don't re-enter here.
+  if (!mContext) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsTArray<nsCString> flavors;
+  nsresult rv = GetTransferableFlavors(aTransferable, flavors);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Filter out MIME types on X11 to prevent unwanted conversions,
+  // see Bug 1611407
+  if (widget::GdkIsX11Display() &&
+      !FilterImportedFlavors(aWhichClipboard, flavors)) {
+    LOGCLIP("    Missing suitable clipboard data, quit.");
+    return NS_OK;
+  }
+
+  for (uint32_t i = 0; i < flavors.Length(); i++) {
+    nsCString& flavorStr = flavors[i];
+
+    if (flavorStr.EqualsLiteral(kJPEGImageMime) ||
+        flavorStr.EqualsLiteral(kJPGImageMime) ||
+        flavorStr.EqualsLiteral(kPNGImageMime) ||
+        flavorStr.EqualsLiteral(kGIFImageMime)) {
+      // Emulate support for image/jpg
+      if (flavorStr.EqualsLiteral(kJPGImageMime)) {
+        flavorStr.Assign(kJPEGImageMime);
+      }
+
+      LOGCLIP("    Getting image %s MIME clipboard data\n", flavorStr.get());
+
+      auto clipboardData =
+          mContext->GetClipboardData(flavorStr.get(), aWhichClipboard);
+      if (!clipboardData) {
+        LOGCLIP("    %s type is missing\n", flavorStr.get());
+        continue;
+      }
+
+      nsCOMPtr<nsIInputStream> byteStream;
+      NS_NewByteInputStream(getter_AddRefs(byteStream), clipboardData.AsSpan(),
+                            NS_ASSIGNMENT_COPY);
+      aTransferable->SetTransferData(flavorStr.get(), byteStream);
+      LOGCLIP("    got %s MIME data\n", flavorStr.get());
+      return NS_OK;
+    }
+
+    // Special case text/plain since we can convert any
+    // string into text/plain
+    if (flavorStr.EqualsLiteral(kTextMime)) {
+      LOGCLIP("    Getting text %s MIME clipboard data\n", flavorStr.get());
+
+      auto clipboardData = mContext->GetClipboardText(aWhichClipboard);
+      if (!clipboardData) {
+        LOGCLIP("    failed to get text data\n");
+        // If the type was text/plain and we couldn't get
+        // text off the clipboard, run the next loop
+        // iteration.
+        continue;
+      }
+
+      // Convert utf-8 into our text format.
+      NS_ConvertUTF8toUTF16 ucs2string(clipboardData.get());
+      SetTransferableData(aTransferable, flavorStr,
+                          (const char*)ucs2string.BeginReading(),
+                          ucs2string.Length() * 2);
+
+      LOGCLIP("    got text data, length %zd\n", ucs2string.Length());
+      return NS_OK;
+    }
+
+    if (flavorStr.EqualsLiteral(kFileMime)) {
+      LOGCLIP("    Getting %s file clipboard data\n", flavorStr.get());
+
+      auto clipboardData =
+          mContext->GetClipboardData(kURIListMime, aWhichClipboard);
+      if (!clipboardData) {
+        LOGCLIP("    text/uri-list type is missing\n");
+        continue;
+      }
+
+      nsDependentCSubstring fileName(clipboardData.AsSpan());
+      if (!TransferableSetFile(aTransferable, fileName)) {
+        continue;
+      }
+      return NS_OK;
+    }
+
+    LOGCLIP("    Getting %s MIME clipboard data\n", flavorStr.get());
+
+    auto clipboardData =
+        mContext->GetClipboardData(flavorStr.get(), aWhichClipboard);
+
+#ifdef MOZ_LOGGING
+    if (!clipboardData) {
+      LOGCLIP("    %s type is missing\n", flavorStr.get());
+    }
+#endif
+
+    if (clipboardData) {
+      LOGCLIP("    got %s mime type data.\n", flavorStr.get());
+
+      // Special case text/html since we can convert into UCS2
+      if (flavorStr.EqualsLiteral(kHTMLMime)) {
+        if (!TransferableSetHTML(aTransferable, clipboardData.AsSpan())) {
+          continue;
+        }
+      } else {
+        auto span = clipboardData.AsSpan();
+        SetTransferableData(aTransferable, flavorStr, span.data(),
+                            span.Length());
+      }
+      return NS_OK;
+    }
+  }
+
+  LOGCLIP("    failed to get clipboard content.\n");
+  return NS_OK;
+}
+
+enum DataType {
+  DATATYPE_IMAGE,
+  DATATYPE_FILE,
+  DATATYPE_HTML,
+  DATATYPE_RAW,
+};
+
+struct DataCallbackHandler {
+  RefPtr<nsITransferable> mTransferable;
+  nsBaseClipboard::GetDataCallback mDataCallback;
+  nsCString mMimeType;
+  DataType mDataType;
+
+  explicit DataCallbackHandler(RefPtr<nsITransferable> aTransferable,
+                               nsBaseClipboard::GetDataCallback&& aDataCallback,
+                               const char* aMimeType,
+                               DataType aDataType = DATATYPE_RAW)
+      : mTransferable(std::move(aTransferable)),
+        mDataCallback(std::move(aDataCallback)),
+        mMimeType(aMimeType),
+        mDataType(aDataType) {
+    MOZ_COUNT_CTOR(DataCallbackHandler);
+    LOGCLIP("DataCallbackHandler created [%p] MIME %s type %d", this,
+            mMimeType.get(), mDataType);
+  }
+  ~DataCallbackHandler() {
+    LOGCLIP("DataCallbackHandler deleted [%p]", this);
+    MOZ_COUNT_DTOR(DataCallbackHandler);
+  }
+};
+
+static void AsyncGetTextImpl(nsITransferable* aTransferable,
+                             int32_t aWhichClipboard,
+                             nsBaseClipboard::GetDataCallback&& aCallback) {
+  LOGCLIP("AsyncGetText() type '%s'",
+          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                              : "clipboard");
+
+  gtk_clipboard_request_text(
+      gtk_clipboard_get(GetSelectionAtom(aWhichClipboard)),
+      [](GtkClipboard* aClipboard, const gchar* aText, gpointer aData) -> void {
+        UniquePtr<DataCallbackHandler> ref(
+            static_cast<DataCallbackHandler*>(aData));
+        LOGCLIP("AsyncGetText async handler of [%p]", aData);
+
+        size_t dataLength = aText ? strlen(aText) : 0;
+        if (dataLength <= 0) {
+          LOGCLIP("  quit, text is not available");
+          ref->mDataCallback(NS_OK);
+          return;
+        }
+
+        // Convert utf-8 into our unicode format.
+        NS_ConvertUTF8toUTF16 utf16string(aText, dataLength);
+        nsLiteralCString flavor(kTextMime);
+        SetTransferableData(ref->mTransferable, flavor,
+                            (const char*)utf16string.BeginReading(),
+                            utf16string.Length() * 2);
+        LOGCLIP("  text is set, length = %d", (int)dataLength);
+        ref->mDataCallback(NS_OK);
+      },
+      new DataCallbackHandler(aTransferable, std::move(aCallback), kTextMime));
+}
+
+static void AsyncGetDataImpl(nsITransferable* aTransferable,
+                             int32_t aWhichClipboard, const char* aMimeType,
+                             DataType aDataType,
+                             nsBaseClipboard::GetDataCallback&& aCallback) {
+  LOGCLIP("AsyncGetData() type '%s'",
+          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                              : "clipboard");
+
+  const char* gtkMIMEType = nullptr;
+  switch (aDataType) {
+    case DATATYPE_FILE:
+      // Don't ask Gtk for application/x-moz-file
+      gtkMIMEType = kURIListMime;
+      break;
+    case DATATYPE_IMAGE:
+    case DATATYPE_HTML:
+    case DATATYPE_RAW:
+      gtkMIMEType = aMimeType;
+      break;
+  }
+
+  gtk_clipboard_request_contents(
+      gtk_clipboard_get(GetSelectionAtom(aWhichClipboard)),
+      gdk_atom_intern(gtkMIMEType, FALSE),
+      [](GtkClipboard* aClipboard, GtkSelectionData* aSelection,
+         gpointer aData) -> void {
+        UniquePtr<DataCallbackHandler> ref(
+            static_cast<DataCallbackHandler*>(aData));
+        LOGCLIP("AsyncGetData async handler [%p] MIME %s type %d", aData,
+                ref->mMimeType.get(), ref->mDataType);
+
+        int dataLength = gtk_selection_data_get_length(aSelection);
+        if (dataLength <= 0) {
+          ref->mDataCallback(NS_OK);
+          return;
+        }
+        const char* data = (const char*)gtk_selection_data_get_data(aSelection);
+        if (!data) {
+          ref->mDataCallback(NS_OK);
+          return;
+        }
+        switch (ref->mDataType) {
+          case DATATYPE_IMAGE: {
+            LOGCLIP("  set image clipboard data");
+            nsCOMPtr<nsIInputStream> byteStream;
+            NS_NewByteInputStream(getter_AddRefs(byteStream),
+                                  Span(data, dataLength), NS_ASSIGNMENT_COPY);
+            ref->mTransferable->SetTransferData(ref->mMimeType.get(),
+                                                byteStream);
+            break;
+          }
+          case DATATYPE_FILE: {
+            LOGCLIP("  set file clipboard data");
+            nsDependentCSubstring file(data, dataLength);
+            TransferableSetFile(ref->mTransferable, file);
+            break;
+          }
+          case DATATYPE_HTML: {
+            LOGCLIP("  html clipboard data");
+            Span dataSpan(data, dataLength);
+            TransferableSetHTML(ref->mTransferable, dataSpan);
+            break;
+          }
+          case DATATYPE_RAW: {
+            LOGCLIP("  raw clipboard data %s", ref->mMimeType.get());
+            SetTransferableData(ref->mTransferable, ref->mMimeType, data,
+                                dataLength);
+            break;
+          }
+        }
+        ref->mDataCallback(NS_OK);
+      },
+      new DataCallbackHandler(aTransferable, std::move(aCallback), aMimeType,
+                              aDataType));
+}
+
+static void AsyncGetDataFlavor(nsITransferable* aTransferable,
+                               int32_t aWhichClipboard, nsCString& aFlavorStr,
+                               nsBaseClipboard::GetDataCallback&& aCallback) {
+  if (aFlavorStr.EqualsLiteral(kJPEGImageMime) ||
+      aFlavorStr.EqualsLiteral(kJPGImageMime) ||
+      aFlavorStr.EqualsLiteral(kPNGImageMime) ||
+      aFlavorStr.EqualsLiteral(kGIFImageMime)) {
+    // Emulate support for image/jpg
+    if (aFlavorStr.EqualsLiteral(kJPGImageMime)) {
+      aFlavorStr.Assign(kJPEGImageMime);
+    }
+    LOGCLIP("  Getting image %s MIME clipboard data", aFlavorStr.get());
+    AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
+                     DATATYPE_IMAGE, std::move(aCallback));
+    return;
+  }
+  // Special case text/plain since we can convert any
+  // string into text/plain
+  if (aFlavorStr.EqualsLiteral(kTextMime)) {
+    LOGCLIP("  Getting unicode clipboard data");
+    AsyncGetTextImpl(aTransferable, aWhichClipboard, std::move(aCallback));
+    return;
+  }
+  if (aFlavorStr.EqualsLiteral(kFileMime)) {
+    LOGCLIP("  Getting file clipboard data\n");
+    AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
+                     DATATYPE_FILE, std::move(aCallback));
+    return;
+  }
+  if (aFlavorStr.EqualsLiteral(kHTMLMime)) {
+    LOGCLIP("  Getting HTML clipboard data");
+    AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
+                     DATATYPE_HTML, std::move(aCallback));
+    return;
+  }
+  LOGCLIP("  Getting raw %s MIME clipboard data\n", aFlavorStr.get());
+  AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
+                   DATATYPE_RAW, std::move(aCallback));
+}
+
+void nsClipboard::AsyncGetNativeClipboardData(nsITransferable* aTransferable,
+                                              int32_t aWhichClipboard,
+                                              GetDataCallback&& aCallback) {
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  LOGCLIP("nsClipboard::AsyncGetNativeClipboardData (%s)",
+          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                              : "clipboard");
+  nsTArray<nsCString> importedFlavors;
+  nsresult rv = GetTransferableFlavors(aTransferable, importedFlavors);
+  if (NS_FAILED(rv)) {
+    aCallback(rv);
+    return;
+  }
+
+  auto flavorsNum = importedFlavors.Length();
+  if (!flavorsNum) {
+    aCallback(NS_OK);
+    return;
+  }
+#ifdef MOZ_LOGGING
+  if (flavorsNum > 1) {
+    LOGCLIP("  Only first MIME type (%s) will be imported from clipboard!",
+            importedFlavors[0].get());
+  }
+#endif
+
+  // Filter out MIME types on X11 to prevent unwanted conversions,
+  // see Bug 1611407
+  if (widget::GdkIsX11Display()) {
+    AsyncHasNativeClipboardDataMatchingFlavors(
+        importedFlavors, aWhichClipboard,
+        [aWhichClipboard, transferable = nsCOMPtr{aTransferable},
+         callback = std::move(aCallback)](auto aResultOrError) mutable {
+          if (aResultOrError.isErr()) {
+            callback(aResultOrError.unwrapErr());
+            return;
+          }
+
+          nsTArray<nsCString> clipboardFlavors =
+              std::move(aResultOrError.unwrap());
+          if (!clipboardFlavors.Length()) {
+            LOGCLIP("  no flavors in clipboard, quit.");
+            callback(NS_OK);
+            return;
+          }
+
+          AsyncGetDataFlavor(transferable, aWhichClipboard, clipboardFlavors[0],
+                             std::move(callback));
+        });
+    return;
+  }
+
+  // Read clipboard directly on Wayland
+  AsyncGetDataFlavor(aTransferable, aWhichClipboard, importedFlavors[0],
+                     std::move(aCallback));
+}
+
+nsresult nsClipboard::EmptyNativeClipboardData(int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  LOGCLIP("nsClipboard::EmptyNativeClipboardData (%s)\n",
+          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  if (aWhichClipboard == kSelectionClipboard) {
+    if (mSelectionTransferable) {
+      gtk_clipboard_clear(gtk_clipboard_get(GDK_SELECTION_PRIMARY));
+      MOZ_ASSERT(!mSelectionTransferable);
+    }
+  } else {
+    if (mGlobalTransferable) {
+      gtk_clipboard_clear(gtk_clipboard_get(GDK_SELECTION_CLIPBOARD));
+      MOZ_ASSERT(!mGlobalTransferable);
+    }
+  }
+  ClearCachedTargets(aWhichClipboard);
+  return NS_OK;
+}
+
+void nsClipboard::ClearTransferable(int32_t aWhichClipboard) {
+  if (aWhichClipboard == kSelectionClipboard) {
+    mSelectionSequenceNumber++;
+    mSelectionTransferable = nullptr;
+  } else {
+    mGlobalSequenceNumber++;
+    mGlobalTransferable = nullptr;
+  }
+}
+
+static bool FlavorMatchesTarget(const nsACString& aFlavor, GdkAtom aTarget) {
+  GUniquePtr<gchar> atom_name(gdk_atom_name(aTarget));
+  if (!atom_name) {
+    return false;
+  }
+  if (aFlavor.Equals(atom_name.get())) {
+    LOGCLIP("    has %s\n", atom_name.get());
+    return true;
+  }
+  // X clipboard supports image/jpeg, but we want to emulate support
+  // for image/jpg as well
+  if (aFlavor.EqualsLiteral(kJPGImageMime) &&
+      !strcmp(atom_name.get(), kJPEGImageMime)) {
+    LOGCLIP("    has image/jpg\n");
+    return true;
+  }
+  // application/x-moz-file should be treated like text/uri-list
+  if (aFlavor.EqualsLiteral(kFileMime) &&
+      !strcmp(atom_name.get(), kURIListMime)) {
+    LOGCLIP("    has text/uri-list treating as application/x-moz-file");
+    return true;
+  }
+  return false;
+}
+
+mozilla::Result<bool, nsresult>
+nsClipboard::HasNativeClipboardDataMatchingFlavors(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  LOGCLIP("nsClipboard::HasNativeClipboardDataMatchingFlavors (%s)\n",
+          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+
+  if (!mContext) {
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  auto targets = mContext->GetTargets(aWhichClipboard);
+  if (!targets) {
+    LOGCLIP("    no targes at clipboard (null)\n");
+    return false;
+  }
+
+#ifdef MOZ_LOGGING
+  if (LOGCLIP_ENABLED()) {
+    LOGCLIP("    Asking for content:\n");
+    for (auto& flavor : aFlavorList) {
+      LOGCLIP("        MIME %s\n", flavor.get());
+    }
+    LOGCLIP("    Clipboard content (target nums %zu):\n",
+            targets.AsSpan().Length());
+    for (const auto& target : targets.AsSpan()) {
+      GUniquePtr<gchar> atom_name(gdk_atom_name(target));
+      if (!atom_name) {
+        LOGCLIP("        failed to get MIME\n");
+        continue;
+      }
+      LOGCLIP("        MIME %s\n", atom_name.get());
+    }
+  }
+#endif
+
+  // Walk through the provided types and try to match it to a
+  // provided type.
+  for (auto& flavor : aFlavorList) {
+    // We special case text/plain here.
+    if (flavor.EqualsLiteral(kTextMime) &&
+        gtk_targets_include_text(targets.AsSpan().data(),
+                                 targets.AsSpan().Length())) {
+      LOGCLIP("    has kTextMime\n");
+      return true;
+    }
+    for (const auto& target : targets.AsSpan()) {
+      if (FlavorMatchesTarget(flavor, target)) {
+        return true;
+      }
+    }
+  }
+
+  LOGCLIP("    no targes at clipboard (bad match)\n");
+  return false;
+}
+
+struct TragetCallbackHandler {
+  TragetCallbackHandler(const nsTArray<nsCString>& aAcceptedFlavorList,
+                        nsBaseClipboard::HasMatchingFlavorsCallback&& aCallback)
+      : mAcceptedFlavorList(aAcceptedFlavorList.Clone()),
+        mCallback(std::move(aCallback)) {
+    LOGCLIP("TragetCallbackHandler(%p) created", this);
+  }
+  ~TragetCallbackHandler() {
+    LOGCLIP("TragetCallbackHandler(%p) deleted", this);
+  }
+  nsTArray<nsCString> mAcceptedFlavorList;
+  nsBaseClipboard::HasMatchingFlavorsCallback mCallback;
+};
+
+void nsClipboard::AsyncHasNativeClipboardDataMatchingFlavors(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard,
+    nsBaseClipboard::HasMatchingFlavorsCallback&& aCallback) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  LOGCLIP("nsClipboard::AsyncHasNativeClipboardDataMatchingFlavors (%s)",
+          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+
+  gtk_clipboard_request_contents(
+      gtk_clipboard_get(GetSelectionAtom(aWhichClipboard)),
+      gdk_atom_intern("TARGETS", FALSE),
+      [](GtkClipboard* aClipboard, GtkSelectionData* aSelection,
+         gpointer aData) -> void {
+        LOGCLIP("gtk_clipboard_request_contents async handler (%p)", aData);
+        UniquePtr<TragetCallbackHandler> handler(
+            static_cast<TragetCallbackHandler*>(aData));
+
+        GdkAtom* targets = nullptr;
+        gint targetsNum = 0;
+        if (gtk_selection_data_get_length(aSelection) > 0) {
+          gtk_selection_data_get_targets(aSelection, &targets, &targetsNum);
+        }
+        nsTArray<nsCString> results;
+        if (targetsNum) {
+          for (auto& flavor : handler->mAcceptedFlavorList) {
+            LOGCLIP("  looking for %s", flavor.get());
+            if (flavor.EqualsLiteral(kTextMime) &&
+                gtk_targets_include_text(targets, targetsNum)) {
+              results.AppendElement(flavor);
+              LOGCLIP("    has kTextMime\n");
+              continue;
+            }
+            for (int i = 0; i < targetsNum; i++) {
+              if (FlavorMatchesTarget(flavor, targets[i])) {
+                results.AppendElement(flavor);
+              }
+            }
+          }
+        }
+        handler->mCallback(std::move(results));
+      },
+      new TragetCallbackHandler(aFlavorList, std::move(aCallback)));
+}
+
+nsITransferable* nsClipboard::GetTransferable(int32_t aWhichClipboard) {
+  nsITransferable* retval;
+
+  if (aWhichClipboard == kSelectionClipboard)
+    retval = mSelectionTransferable.get();
+  else
+    retval = mGlobalTransferable.get();
+
+  return retval;
+}
+
+void nsClipboard::SelectionGetEvent(GtkClipboard* aClipboard,
+                                    GtkSelectionData* aSelectionData) {
+  // Someone has asked us to hand them something.  The first thing
+  // that we want to do is see if that something includes text.  If
+  // it does, try to give it text/plain after converting it to
+  // utf-8.
+
+  int32_t whichClipboard;
+
+  // which clipboard?
+  GdkAtom selection = gtk_selection_data_get_selection(aSelectionData);
+  if (selection == GDK_SELECTION_PRIMARY)
+    whichClipboard = kSelectionClipboard;
+  else if (selection == GDK_SELECTION_CLIPBOARD)
+    whichClipboard = kGlobalClipboard;
+  else
+    return;  // THAT AIN'T NO CLIPBOARD I EVER HEARD OF
+
+  LOGCLIP("nsClipboard::SelectionGetEvent (%s)\n",
+          whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+
+  nsCOMPtr<nsITransferable> trans = GetTransferable(whichClipboard);
+  if (!trans) {
+    // We have nothing to serve
+    LOGCLIP("nsClipboard::SelectionGetEvent() - %s clipboard is empty!\n",
+            whichClipboard == kSelectionClipboard ? "Primary" : "Clipboard");
+    return;
+  }
+
+  nsresult rv;
+  nsCOMPtr<nsISupports> item;
+
+  GdkAtom selectionTarget = gtk_selection_data_get_target(aSelectionData);
+  LOGCLIP("  selection target %s\n",
+          GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+
+  // Check to see if the selection data is some text type.
+  if (gtk_targets_include_text(&selectionTarget, 1)) {
+    LOGCLIP("  providing text/plain data\n");
+    // Try to convert our internal type into a text string.  Get
+    // the transferable for this clipboard and try to get the
+    // text/plain type for it.
+    rv = trans->GetTransferData("text/plain", getter_AddRefs(item));
+    if (NS_FAILED(rv) || !item) {
+      LOGCLIP("  GetTransferData() failed to get text/plain!\n");
+      return;
+    }
+
+    nsCOMPtr<nsISupportsString> wideString;
+    wideString = do_QueryInterface(item);
+    if (!wideString) return;
+
+    nsAutoString ucs2string;
+    wideString->GetData(ucs2string);
+    NS_ConvertUTF16toUTF8 utf8string(ucs2string);
+
+    LOGCLIP("  sent %zd bytes of utf-8 data\n", utf8string.Length());
+    if (selectionTarget == gdk_atom_intern("text/plain;charset=utf-8", FALSE)) {
+      LOGCLIP(
+          "  using gtk_selection_data_set for 'text/plain;charset=utf-8'\n");
+      // Bypass gtk_selection_data_set_text, which will convert \n to \r\n
+      // in some versions of GTK.
+      gtk_selection_data_set(aSelectionData, selectionTarget, 8,
+                             reinterpret_cast<const guchar*>(utf8string.get()),
+                             utf8string.Length());
+    } else {
+      gtk_selection_data_set_text(aSelectionData, utf8string.get(),
+                                  utf8string.Length());
+    }
+    return;
+  }
+
+  // Check to see if the selection data is an image type
+  if (gtk_targets_include_image(&selectionTarget, 1, TRUE)) {
+    LOGCLIP("  providing image data\n");
+    // Look through our transfer data for the image
+    static const char* const imageMimeTypes[] = {kNativeImageMime,
+                                                 kPNGImageMime, kJPEGImageMime,
+                                                 kJPGImageMime, kGIFImageMime};
+    nsCOMPtr<nsISupports> imageItem;
+    nsCOMPtr<imgIContainer> image;
+    for (uint32_t i = 0; i < ArrayLength(imageMimeTypes); i++) {
+      rv = trans->GetTransferData(imageMimeTypes[i], getter_AddRefs(imageItem));
+      if (NS_FAILED(rv)) {
+        LOGCLIP("    %s is missing at GetTransferData()\n", imageMimeTypes[i]);
+        continue;
+      }
+
+      image = do_QueryInterface(imageItem);
+      if (image) {
+        LOGCLIP("    %s is available at GetTransferData()\n",
+                imageMimeTypes[i]);
+        break;
+      }
+    }
+
+    if (!image) {  // Not getting an image for an image mime type!?
+      LOGCLIP("    Failed to get any image mime from GetTransferData()!\n");
+      return;
+    }
+
+    RefPtr<GdkPixbuf> pixbuf = nsImageToPixbuf::ImageToPixbuf(image);
+    if (!pixbuf) {
+      LOGCLIP("    nsImageToPixbuf::ImageToPixbuf() failed!\n");
+      return;
+    }
+
+    LOGCLIP("    Setting pixbuf image data as %s\n",
+            GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+    gtk_selection_data_set_pixbuf(aSelectionData, pixbuf);
+    return;
+  }
+
+  if (selectionTarget == gdk_atom_intern(kHTMLMime, FALSE)) {
+    LOGCLIP("  providing %s data\n", kHTMLMime);
+    rv = trans->GetTransferData(kHTMLMime, getter_AddRefs(item));
+    if (NS_FAILED(rv) || !item) {
+      LOGCLIP("  failed to get %s data by GetTransferData()!\n", kHTMLMime);
+      return;
+    }
+
+    nsCOMPtr<nsISupportsString> wideString;
+    wideString = do_QueryInterface(item);
+    if (!wideString) {
+      LOGCLIP("  failed to get wideString interface!");
+      return;
+    }
+
+    nsAutoString ucs2string;
+    wideString->GetData(ucs2string);
+
+    nsAutoCString html;
+    // Add the prefix so the encoding is correctly detected.
+    html.AppendLiteral(kHTMLMarkupPrefix);
+    AppendUTF16toUTF8(ucs2string, html);
+
+    LOGCLIP("  Setting %zd bytes of %s data\n", html.Length(),
+            GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+    gtk_selection_data_set(aSelectionData, selectionTarget, 8,
+                           (const guchar*)html.get(), html.Length());
+    return;
+  }
+
+  // We put kFileMime onto the clipboard as kURIListMime.
+  if (selectionTarget == gdk_atom_intern(kURIListMime, FALSE)) {
+    LOGCLIP("  providing %s data\n", kURIListMime);
+    rv = trans->GetTransferData(kFileMime, getter_AddRefs(item));
+    if (NS_FAILED(rv) || !item) {
+      LOGCLIP("  failed to get %s data by GetTransferData()!\n", kFileMime);
+      return;
+    }
+
+    nsCOMPtr<nsIFile> file = do_QueryInterface(item);
+    if (!file) {
+      LOGCLIP("  failed to get nsIFile interface!");
+      return;
+    }
+
+    nsCOMPtr<nsIURI> fileURI;
+    rv = NS_NewFileURI(getter_AddRefs(fileURI), file);
+    if (NS_FAILED(rv)) {
+      LOGCLIP("  failed to get fileURI\n");
+      return;
+    }
+
+    nsAutoCString uri;
+    if (NS_FAILED(fileURI->GetSpec(uri))) {
+      LOGCLIP("  failed to get fileURI spec\n");
+      return;
+    }
+
+    LOGCLIP("  Setting %zd bytes of data\n", uri.Length());
+    gtk_selection_data_set(aSelectionData, selectionTarget, 8,
+                           (const guchar*)uri.get(), uri.Length());
+    return;
+  }
+
+  LOGCLIP("  Try if we have anything at GetTransferData() for %s\n",
+          GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+
+  // Try to match up the selection data target to something our
+  // transferable provides.
+  GUniquePtr<gchar> target_name(gdk_atom_name(selectionTarget));
+  if (!target_name) {
+    LOGCLIP("  Failed to get target name!\n");
+    return;
+  }
+
+  rv = trans->GetTransferData(target_name.get(), getter_AddRefs(item));
+  // nothing found?
+  if (NS_FAILED(rv) || !item) {
+    LOGCLIP("  Failed to get anything from GetTransferData()!\n");
+    return;
+  }
+
+  void* primitive_data = nullptr;
+  uint32_t dataLen = 0;
+  nsPrimitiveHelpers::CreateDataFromPrimitive(
+      nsDependentCString(target_name.get()), item, &primitive_data, &dataLen);
+  if (!primitive_data) {
+    LOGCLIP("  Failed to get primitive data!\n");
+    return;
+  }
+
+  LOGCLIP("  Setting %s as a primitive data type, %d bytes\n",
+          target_name.get(), dataLen);
+  gtk_selection_data_set(aSelectionData, selectionTarget,
+                         8, /* 8 bits in a unit */
+                         (const guchar*)primitive_data, dataLen);
+  free(primitive_data);
+}
+
+void nsClipboard::ClearCachedTargets(int32_t aWhichClipboard) {
+  if (aWhichClipboard == kSelectionClipboard) {
+    nsRetrievalContext::ClearCachedTargetsPrimary(nullptr, nullptr, nullptr);
+  } else {
+    nsRetrievalContext::ClearCachedTargetsClipboard(nullptr, nullptr, nullptr);
+  }
+}
+
+void nsClipboard::SelectionClearEvent(GtkClipboard* aGtkClipboard) {
+  int32_t whichClipboard = GetGeckoClipboardType(aGtkClipboard);
+  if (whichClipboard < 0) {
+    return;
+  }
+  LOGCLIP("nsClipboard::SelectionClearEvent (%s)\n",
+          whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  ClearCachedTargets(whichClipboard);
+  ClearTransferable(whichClipboard);
+  ClearClipboardCache(whichClipboard);
+}
+
+void nsClipboard::OwnerChangedEvent(GtkClipboard* aGtkClipboard,
+                                    GdkEventOwnerChange* aEvent) {
+  int32_t whichClipboard = GetGeckoClipboardType(aGtkClipboard);
+  if (whichClipboard < 0) {
+    return;
+  }
+  LOGCLIP("nsClipboard::OwnerChangedEvent (%s)\n",
+          whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  GtkWidget* gtkWidget = [aEvent]() -> GtkWidget* {
+    if (!aEvent->owner) {
+      return nullptr;
+    }
+    gpointer user_data = nullptr;
+    gdk_window_get_user_data(aEvent->owner, &user_data);
+    return GTK_WIDGET(user_data);
+  }();
+  // If we can get GtkWidget from the current clipboard owner, this
+  // owner-changed event must be triggered by ourself via calling
+  // gtk_clipboard_set_with_data, the sequence number should already be handled.
+  if (!gtkWidget) {
+    if (whichClipboard == kSelectionClipboard) {
+      mSelectionSequenceNumber++;
+    } else {
+      mGlobalSequenceNumber++;
+    }
+  }
+
+  ClearCachedTargets(whichClipboard);
+}
+
+void clipboard_get_cb(GtkClipboard* aGtkClipboard,
+                      GtkSelectionData* aSelectionData, guint info,
+                      gpointer user_data) {
+  LOGCLIP("clipboard_get_cb() callback\n");
+  nsClipboard* clipboard = static_cast<nsClipboard*>(user_data);
+  clipboard->SelectionGetEvent(aGtkClipboard, aSelectionData);
+}
+
+void clipboard_clear_cb(GtkClipboard* aGtkClipboard, gpointer user_data) {
+  LOGCLIP("clipboard_clear_cb() callback\n");
+  nsClipboard* clipboard = static_cast<nsClipboard*>(user_data);
+  clipboard->SelectionClearEvent(aGtkClipboard);
+}
+
+void clipboard_owner_change_cb(GtkClipboard* aGtkClipboard,
+                               GdkEventOwnerChange* aEvent,
+                               gpointer aUserData) {
+  LOGCLIP("clipboard_owner_change_cb() callback\n");
+  nsClipboard* clipboard = static_cast<nsClipboard*>(aUserData);
+  clipboard->OwnerChangedEvent(aGtkClipboard, aEvent);
+}
+
+/*
+ * This function extracts the encoding label from the subset of HTML internal
+ * encoding declaration syntax that uses the old long form with double quotes
+ * and without spaces around the equals sign between the "content" attribute
+ * name and the attribute value.
+ *
+ * This was added for the sake of an ancient version of StarOffice
+ * in the pre-UTF-8 era in bug 123389. It is unclear if supporting
+ * non-UTF-8 encodings is still necessary and if this function
+ * still needs to exist.
+ *
+ * As of December 2022, both Gecko and LibreOffice emit an UTF-8
+ * declaration that this function successfully extracts "UTF-8" from,
+ * but that's also the default that we fall back on if this function
+ * fails to extract a label.
+ */
+bool GetHTMLCharset(Span<const char> aData, nsCString& aFoundCharset) {
+  // Assume ASCII first to find "charset" info
+  const nsDependentCSubstring htmlStr(aData);
+  nsACString::const_iterator start, end;
+  htmlStr.BeginReading(start);
+  htmlStr.EndReading(end);
+  nsACString::const_iterator valueStart(start), valueEnd(start);
+
+  if (CaseInsensitiveFindInReadable("CONTENT=\"text/html;"_ns, start, end)) {
+    start = end;
+    htmlStr.EndReading(end);
+
+    if (CaseInsensitiveFindInReadable("charset="_ns, start, end)) {
+      valueStart = end;
+      start = end;
+      htmlStr.EndReading(end);
+
+      if (FindCharInReadable('"', start, end)) valueEnd = start;
+    }
+  }
+  // find "charset" in HTML
+  if (valueStart != valueEnd) {
+    aFoundCharset = Substring(valueStart, valueEnd);
+    ToUpperCase(aFoundCharset);
+    return true;
+  }
+  return false;
+}
diff --git a/widget/gtk/nsClipboard.h b/widget/gtk/nsClipboard.h
new file mode 100644
index 0000000000..0ddbb59827
--- /dev/null
+++ b/widget/gtk/nsClipboard.h
@@ -0,0 +1,177 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsClipboard_h_
+#define __nsClipboard_h_
+
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Span.h"
+#include "nsBaseClipboard.h"
+#include "nsIClipboard.h"
+#include "nsIObserver.h"
+#include "nsCOMPtr.h"
+#include "GUniquePtr.h"
+#include <gtk/gtk.h>
+
+#ifdef MOZ_LOGGING
+#  include "mozilla/Logging.h"
+#  include "nsTArray.h"
+#  include "Units.h"
+extern mozilla::LazyLogModule gClipboardLog;
+#  define LOGCLIP(...) \
+    MOZ_LOG(gClipboardLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#  define LOGCLIP_ENABLED() \
+    MOZ_LOG_TEST(gClipboardLog, mozilla::LogLevel::Debug)
+#else
+#  define LOGCLIP(...)
+#  define LOGCLIP_ENABLED() false
+#endif /* MOZ_LOGGING */
+
+class ClipboardTargets {
+  friend class ClipboardData;
+
+  mozilla::GUniquePtr<GdkAtom> mTargets;
+  uint32_t mCount = 0;
+
+ public:
+  ClipboardTargets() = default;
+  ClipboardTargets(mozilla::GUniquePtr<GdkAtom> aTargets, uint32_t aCount)
+      : mTargets(std::move(aTargets)), mCount(aCount) {}
+
+  void Set(ClipboardTargets);
+  ClipboardTargets Clone();
+  void Clear() {
+    mTargets = nullptr;
+    mCount = 0;
+  };
+
+  mozilla::Span<GdkAtom> AsSpan() const { return {mTargets.get(), mCount}; }
+  explicit operator bool() const { return bool(mTargets); }
+};
+
+class ClipboardData {
+  mozilla::GUniquePtr<char> mData;
+  uint32_t mLength = 0;
+
+ public:
+  ClipboardData() = default;
+
+  void SetData(mozilla::Span<const uint8_t>);
+  void SetText(mozilla::Span<const char>);
+  void SetTargets(ClipboardTargets);
+
+  ClipboardTargets ExtractTargets();
+  mozilla::GUniquePtr<char> ExtractText() {
+    mLength = 0;
+    return std::move(mData);
+  }
+
+  mozilla::Span<char> AsSpan() const { return {mData.get(), mLength}; }
+  explicit operator bool() const { return bool(mData); }
+};
+
+enum class ClipboardDataType { Data, Text, Targets };
+
+class nsRetrievalContext {
+ public:
+  // We intentionally use unsafe thread refcount as clipboard is used in
+  // main thread only.
+  NS_INLINE_DECL_REFCOUNTING(nsRetrievalContext)
+
+  // Get actual clipboard content (GetClipboardData/GetClipboardText).
+  virtual ClipboardData GetClipboardData(const char* aMimeType,
+                                         int32_t aWhichClipboard) = 0;
+  virtual mozilla::GUniquePtr<char> GetClipboardText(
+      int32_t aWhichClipboard) = 0;
+
+  // Get data mime types which can be obtained from clipboard.
+  ClipboardTargets GetTargets(int32_t aWhichClipboard);
+
+  // Clipboard/Primary selection owner changed. Clear internal cached data.
+  static void ClearCachedTargetsClipboard(GtkClipboard* aClipboard,
+                                          GdkEvent* aEvent, gpointer data);
+  static void ClearCachedTargetsPrimary(GtkClipboard* aClipboard,
+                                        GdkEvent* aEvent, gpointer data);
+
+  nsRetrievalContext() = default;
+
+ protected:
+  virtual ClipboardTargets GetTargetsImpl(int32_t aWhichClipboard) = 0;
+  virtual ~nsRetrievalContext();
+
+  static ClipboardTargets sClipboardTargets;
+  static ClipboardTargets sPrimaryTargets;
+};
+
+class nsClipboard : public nsBaseClipboard, public nsIObserver {
+ public:
+  nsClipboard();
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIOBSERVER
+
+  // Make sure we are initialized, called from the factory
+  // constructor
+  nsresult Init(void);
+
+  // Someone requested the selection
+  void SelectionGetEvent(GtkClipboard* aGtkClipboard,
+                         GtkSelectionData* aSelectionData);
+  void SelectionClearEvent(GtkClipboard* aGtkClipboard);
+
+  // Clipboard owner changed
+  void OwnerChangedEvent(GtkClipboard* aGtkClipboard,
+                         GdkEventOwnerChange* aEvent);
+
+ protected:
+  // Implement the native clipboard behavior.
+  NS_IMETHOD SetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) override;
+  NS_IMETHOD GetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) override;
+  void AsyncGetNativeClipboardData(nsITransferable* aTransferable,
+                                   int32_t aWhichClipboard,
+                                   GetDataCallback&& aCallback) override;
+  nsresult EmptyNativeClipboardData(int32_t aWhichClipboard) override;
+  mozilla::Result<int32_t, nsresult> GetNativeClipboardSequenceNumber(
+      int32_t aWhichClipboard) override;
+  mozilla::Result<bool, nsresult> HasNativeClipboardDataMatchingFlavors(
+      const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) override;
+  void AsyncHasNativeClipboardDataMatchingFlavors(
+      const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard,
+      HasMatchingFlavorsCallback&& aCallback) override;
+
+ private:
+  virtual ~nsClipboard();
+
+  // Get our hands on the correct transferable, given a specific
+  // clipboard
+  nsITransferable* GetTransferable(int32_t aWhichClipboard);
+
+  void ClearTransferable(int32_t aWhichClipboard);
+  void ClearCachedTargets(int32_t aWhichClipboard);
+
+  bool FilterImportedFlavors(int32_t aWhichClipboard,
+                             nsTArray<nsCString>& aFlavors);
+
+  // Hang on to our transferables so we can transfer data when asked.
+  nsCOMPtr<nsITransferable> mSelectionTransferable;
+  nsCOMPtr<nsITransferable> mGlobalTransferable;
+  RefPtr<nsRetrievalContext> mContext;
+
+  // Sequence number of the system clipboard data.
+  int32_t mSelectionSequenceNumber = 0;
+  int32_t mGlobalSequenceNumber = 0;
+};
+
+extern const int kClipboardTimeout;
+extern const int kClipboardFastIterationNum;
+
+GdkAtom GetSelectionAtom(int32_t aWhichClipboard);
+int GetGeckoClipboardType(GtkClipboard* aGtkClipboard);
+
+#endif /* __nsClipboard_h_ */
diff --git a/widget/gtk/nsClipboardWayland.cpp b/widget/gtk/nsClipboardWayland.cpp
new file mode 100644
index 0000000000..d179f242dd
--- /dev/null
+++ b/widget/gtk/nsClipboardWayland.cpp
@@ -0,0 +1,75 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsClipboardWayland.h"
+
+#include "AsyncGtkClipboardRequest.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/ScopeExit.h"
+#include "prtime.h"
+
+#include <gtk/gtk.h>
+#include <stdlib.h>
+#include <string.h>
+
+using namespace mozilla;
+
+nsRetrievalContextWayland::nsRetrievalContextWayland() = default;
+
+ClipboardTargets nsRetrievalContextWayland::GetTargetsImpl(
+    int32_t aWhichClipboard) {
+  LOGCLIP("nsRetrievalContextWayland::GetTargetsImpl()\n");
+
+  return WaitForClipboardData(ClipboardDataType::Targets, aWhichClipboard)
+      .ExtractTargets();
+}
+
+ClipboardData nsRetrievalContextWayland::GetClipboardData(
+    const char* aMimeType, int32_t aWhichClipboard) {
+  LOGCLIP("nsRetrievalContextWayland::GetClipboardData() mime %s\n", aMimeType);
+
+  return WaitForClipboardData(ClipboardDataType::Data, aWhichClipboard,
+                              aMimeType);
+}
+
+GUniquePtr<char> nsRetrievalContextWayland::GetClipboardText(
+    int32_t aWhichClipboard) {
+  GdkAtom selection = GetSelectionAtom(aWhichClipboard);
+
+  LOGCLIP("nsRetrievalContextWayland::GetClipboardText(), clipboard %s\n",
+          (selection == GDK_SELECTION_PRIMARY) ? "Primary" : "Selection");
+
+  return WaitForClipboardData(ClipboardDataType::Text, aWhichClipboard)
+      .ExtractText();
+}
+
+ClipboardData nsRetrievalContextWayland::WaitForClipboardData(
+    ClipboardDataType aDataType, int32_t aWhichClipboard,
+    const char* aMimeType) {
+  LOGCLIP("nsRetrievalContextWayland::WaitForClipboardData, MIME %s\n",
+          aMimeType);
+
+  AsyncGtkClipboardRequest request(aDataType, aWhichClipboard, aMimeType);
+  int iteration = 1;
+
+  PRTime entryTime = PR_Now();
+  while (!request.HasCompleted()) {
+    if (iteration++ > kClipboardFastIterationNum) {
+      /* sleep for 10 ms/iteration */
+      PR_Sleep(PR_MillisecondsToInterval(10));
+      if (PR_Now() - entryTime > kClipboardTimeout) {
+        LOGCLIP("  failed to get async clipboard data in time limit\n");
+        break;
+      }
+    }
+    LOGCLIP("doing iteration %d msec %ld ...\n", (iteration - 1),
+            (long)((PR_Now() - entryTime) / 1000));
+    gtk_main_iteration();
+  }
+
+  return request.TakeResult();
+}
diff --git a/widget/gtk/nsClipboardWayland.h b/widget/gtk/nsClipboardWayland.h
new file mode 100644
index 0000000000..cd8dda0772
--- /dev/null
+++ b/widget/gtk/nsClipboardWayland.h
@@ -0,0 +1,28 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsClipboardWayland_h_
+#define __nsClipboardWayland_h_
+
+#include "mozilla/Mutex.h"
+#include "nsClipboard.h"
+
+class nsRetrievalContextWayland final : public nsRetrievalContext {
+ public:
+  nsRetrievalContextWayland();
+
+  ClipboardData GetClipboardData(const char* aMimeType,
+                                 int32_t aWhichClipboard) override;
+  mozilla::GUniquePtr<char> GetClipboardText(int32_t aWhichClipboard) override;
+  ClipboardTargets GetTargetsImpl(int32_t aWhichClipboard) override;
+
+ private:
+  ClipboardData WaitForClipboardData(ClipboardDataType, int32_t aWhichClipboard,
+                                     const char* aMimeType = nullptr);
+};
+
+#endif /* __nsClipboardWayland_h_ */
diff --git a/widget/gtk/nsClipboardX11.cpp b/widget/gtk/nsClipboardX11.cpp
new file mode 100644
index 0000000000..db12d1e69c
--- /dev/null
+++ b/widget/gtk/nsClipboardX11.cpp
@@ -0,0 +1,173 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+
+#include "AsyncGtkClipboardRequest.h"
+#include "nsClipboardX11.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/WidgetUtilsGtk.h"
+
+#include <gtk/gtk.h>
+
+// For manipulation of the X event queue
+#include <X11/Xlib.h>
+#include <poll.h>
+#include <gdk/gdkx.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <unistd.h>
+#include "X11UndefineNone.h"
+
+using namespace mozilla;
+
+nsRetrievalContextX11::nsRetrievalContextX11() = default;
+
+static void DispatchSelectionNotifyEvent(GtkWidget* widget, XEvent* xevent) {
+  GdkWindow* window = gtk_widget_get_window(widget);
+  if (window) {
+    GdkEvent event = {};
+    event.selection.type = GDK_SELECTION_NOTIFY;
+    event.selection.window = window;
+    event.selection.selection =
+        gdk_x11_xatom_to_atom(xevent->xselection.selection);
+    event.selection.target = gdk_x11_xatom_to_atom(xevent->xselection.target);
+    event.selection.property =
+        gdk_x11_xatom_to_atom(xevent->xselection.property);
+    event.selection.time = xevent->xselection.time;
+
+    gtk_widget_event(widget, &event);
+  }
+}
+
+static void DispatchPropertyNotifyEvent(GtkWidget* widget, XEvent* xevent) {
+  GdkWindow* window = gtk_widget_get_window(widget);
+  if (window && ((gdk_window_get_events(window)) & GDK_PROPERTY_CHANGE_MASK)) {
+    GdkEvent event = {};
+    event.property.type = GDK_PROPERTY_NOTIFY;
+    event.property.window = window;
+    event.property.atom = gdk_x11_xatom_to_atom(xevent->xproperty.atom);
+    event.property.time = xevent->xproperty.time;
+    event.property.state = xevent->xproperty.state;
+
+    gtk_widget_event(widget, &event);
+  }
+}
+
+struct checkEventContext {
+  GtkWidget* cbWidget;
+  Atom selAtom;
+};
+
+static Bool checkEventProc(Display* display, XEvent* event, XPointer arg) {
+  checkEventContext* context = (checkEventContext*)arg;
+
+  if (event->xany.type == SelectionNotify ||
+      (event->xany.type == PropertyNotify &&
+       event->xproperty.atom == context->selAtom)) {
+    GdkWindow* cbWindow = gdk_x11_window_lookup_for_display(
+        gdk_x11_lookup_xdisplay(display), event->xany.window);
+    if (cbWindow) {
+      GtkWidget* cbWidget = nullptr;
+      gdk_window_get_user_data(cbWindow, (gpointer*)&cbWidget);
+      if (cbWidget && GTK_IS_WIDGET(cbWidget)) {
+        context->cbWidget = cbWidget;
+        return X11True;
+      }
+    }
+  }
+
+  return X11False;
+}
+
+ClipboardData nsRetrievalContextX11::WaitForClipboardData(
+    ClipboardDataType aDataType, int32_t aWhichClipboard,
+    const char* aMimeType) {
+  AsyncGtkClipboardRequest request(aDataType, aWhichClipboard, aMimeType);
+  if (request.HasCompleted()) {
+    // the request completed synchronously
+    return request.TakeResult();
+  }
+
+  GdkDisplay* gdkDisplay = gdk_display_get_default();
+  // gdk_display_get_default() returns null on headless
+  if (widget::GdkIsX11Display(gdkDisplay)) {
+    Display* xDisplay = GDK_DISPLAY_XDISPLAY(gdkDisplay);
+    checkEventContext context;
+    context.cbWidget = nullptr;
+    context.selAtom =
+        gdk_x11_atom_to_xatom(gdk_atom_intern("GDK_SELECTION", FALSE));
+
+    // Send X events which are relevant to the ongoing selection retrieval
+    // to the clipboard widget.  Wait until either the operation completes, or
+    // we hit our timeout.  All other X events remain queued.
+
+    int poll_result;
+
+    struct pollfd pfd;
+    pfd.fd = ConnectionNumber(xDisplay);
+    pfd.events = POLLIN;
+    TimeStamp start = TimeStamp::Now();
+
+    do {
+      XEvent xevent;
+
+      while (XCheckIfEvent(xDisplay, &xevent, checkEventProc,
+                           (XPointer)&context)) {
+        if (xevent.xany.type == SelectionNotify)
+          DispatchSelectionNotifyEvent(context.cbWidget, &xevent);
+        else
+          DispatchPropertyNotifyEvent(context.cbWidget, &xevent);
+
+        if (request.HasCompleted()) {
+          return request.TakeResult();
+        }
+      }
+
+      TimeStamp now = TimeStamp::Now();
+      int timeout = std::max<int>(
+          0, kClipboardTimeout / 1000 - (now - start).ToMilliseconds());
+      poll_result = poll(&pfd, 1, timeout);
+    } while ((poll_result == 1 && (pfd.revents & (POLLHUP | POLLERR)) == 0) ||
+             (poll_result == -1 && errno == EINTR));
+  }
+
+  LOGCLIP("exceeded clipboard timeout");
+  return {};
+}
+
+ClipboardTargets nsRetrievalContextX11::GetTargetsImpl(
+    int32_t aWhichClipboard) {
+  LOGCLIP("nsRetrievalContextX11::GetTargetsImpl(%s)\n",
+          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                              : "clipboard");
+  return WaitForClipboardData(ClipboardDataType::Targets, aWhichClipboard)
+      .ExtractTargets();
+}
+
+ClipboardData nsRetrievalContextX11::GetClipboardData(const char* aMimeType,
+                                                      int32_t aWhichClipboard) {
+  LOGCLIP("nsRetrievalContextX11::GetClipboardData(%s) MIME %s\n",
+          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                              : "clipboard",
+          aMimeType);
+
+  return WaitForClipboardData(ClipboardDataType::Data, aWhichClipboard,
+                              aMimeType);
+}
+
+GUniquePtr<char> nsRetrievalContextX11::GetClipboardText(
+    int32_t aWhichClipboard) {
+  LOGCLIP("nsRetrievalContextX11::GetClipboardText(%s)\n",
+          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                              : "clipboard");
+
+  return WaitForClipboardData(ClipboardDataType::Text, aWhichClipboard)
+      .ExtractText();
+}
diff --git a/widget/gtk/nsClipboardX11.h b/widget/gtk/nsClipboardX11.h
new file mode 100644
index 0000000000..c143222d3a
--- /dev/null
+++ b/widget/gtk/nsClipboardX11.h
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsClipboardX11_h_
+#define __nsClipboardX11_h_
+
+#include <gtk/gtk.h>
+
+#include "mozilla/Maybe.h"
+#include "nsClipboard.h"
+
+class nsRetrievalContextX11 : public nsRetrievalContext {
+ public:
+  ClipboardData GetClipboardData(const char* aMimeType,
+                                 int32_t aWhichClipboard) override;
+  mozilla::GUniquePtr<char> GetClipboardText(int32_t aWhichClipboard) override;
+  ClipboardTargets GetTargetsImpl(int32_t aWhichClipboard) override;
+
+  nsRetrievalContextX11();
+
+ private:
+  // Spins X event loop until timing out or being completed.
+  ClipboardData WaitForClipboardData(ClipboardDataType aDataType,
+                                     int32_t aWhichClipboard,
+                                     const char* aMimeType = nullptr);
+};
+
+#endif /* __nsClipboardX11_h_ */
diff --git a/widget/gtk/nsColorPicker.cpp b/widget/gtk/nsColorPicker.cpp
new file mode 100644
index 0000000000..4719710d9e
--- /dev/null
+++ b/widget/gtk/nsColorPicker.cpp
@@ -0,0 +1,253 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <gtk/gtk.h>
+
+#include "mozilla/Maybe.h"
+#include "mozilla/dom/HTMLInputElement.h"
+#include "nsColor.h"
+#include "nsColorPicker.h"
+#include "nsGtkUtils.h"
+#include "nsIWidget.h"
+#include "WidgetUtils.h"
+#include "nsPIDOMWindow.h"
+
+using mozilla::dom::HTMLInputElement;
+
+NS_IMPL_ISUPPORTS(nsColorPicker, nsIColorPicker)
+
+#if defined(ACTIVATE_GTK3_COLOR_PICKER)
+int nsColorPicker::convertGdkRgbaComponent(gdouble color_component) {
+  // GdkRGBA value is in range [0.0..1.0]. We need something in range [0..255]
+  return color_component * 255 + 0.5;
+}
+
+gdouble nsColorPicker::convertToGdkRgbaComponent(int color_component) {
+  return color_component / 255.0;
+}
+
+GdkRGBA nsColorPicker::convertToRgbaColor(nscolor color) {
+  GdkRGBA result = {convertToGdkRgbaComponent(NS_GET_R(color)),
+                    convertToGdkRgbaComponent(NS_GET_G(color)),
+                    convertToGdkRgbaComponent(NS_GET_B(color)),
+                    convertToGdkRgbaComponent(NS_GET_A(color))};
+
+  return result;
+}
+#else
+int nsColorPicker::convertGdkColorComponent(guint16 color_component) {
+  // GdkColor value is in range [0..65535]. We need something in range [0..255]
+  return (color_component * 255 + 127) / 65535;
+}
+
+guint16 nsColorPicker::convertToGdkColorComponent(int color_component) {
+  return color_component * 65535 / 255;
+}
+
+GdkColor nsColorPicker::convertToGdkColor(nscolor color) {
+  GdkColor result = {0 /* obsolete, unused 'pixel' value */,
+                     convertToGdkColorComponent(NS_GET_R(color)),
+                     convertToGdkColorComponent(NS_GET_G(color)),
+                     convertToGdkColorComponent(NS_GET_B(color))};
+
+  return result;
+}
+
+GtkColorSelection* nsColorPicker::WidgetGetColorSelection(GtkWidget* widget) {
+  return GTK_COLOR_SELECTION(gtk_color_selection_dialog_get_color_selection(
+      GTK_COLOR_SELECTION_DIALOG(widget)));
+}
+#endif
+
+NS_IMETHODIMP nsColorPicker::Init(mozIDOMWindowProxy* aParent,
+                                  const nsAString& title,
+                                  const nsAString& initialColor,
+                                  const nsTArray<nsString>& aDefaultColors) {
+  auto* parent = nsPIDOMWindowOuter::From(aParent);
+  mParentWidget = mozilla::widget::WidgetUtils::DOMWindowToWidget(parent);
+  mTitle = title;
+  mInitialColor = initialColor;
+  mDefaultColors.Assign(aDefaultColors);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsColorPicker::Open(
+    nsIColorPickerShownCallback* aColorPickerShownCallback) {
+  auto maybeColor = HTMLInputElement::ParseSimpleColor(mInitialColor);
+  if (maybeColor.isNothing()) {
+    return NS_ERROR_FAILURE;
+  }
+  nscolor color = maybeColor.value();
+
+  if (mCallback) {
+    // It means Open has already been called: this is not allowed
+    NS_WARNING("mCallback is already set. Open called twice?");
+    return NS_ERROR_FAILURE;
+  }
+  mCallback = aColorPickerShownCallback;
+
+  NS_ConvertUTF16toUTF8 title(mTitle);
+  GtkWindow* parent_window =
+      GTK_WINDOW(mParentWidget->GetNativeData(NS_NATIVE_SHELLWIDGET));
+
+#if defined(ACTIVATE_GTK3_COLOR_PICKER)
+  GtkWidget* color_chooser =
+      gtk_color_chooser_dialog_new(title.get(), parent_window);
+
+  if (parent_window) {
+    GtkWindow* window = GTK_WINDOW(color_chooser);
+    gtk_window_set_destroy_with_parent(window, TRUE);
+    if (gtk_window_get_modal(parent_window)) {
+      gtk_window_set_modal(window, TRUE);
+    }
+  }
+
+  gtk_color_chooser_set_use_alpha(GTK_COLOR_CHOOSER(color_chooser), FALSE);
+
+  // Setting the default colors will put them into "Custom" colors list.
+  for (const nsString& defaultColor : mDefaultColors) {
+    if (auto color = HTMLInputElement::ParseSimpleColor(defaultColor)) {
+      GdkRGBA color_rgba = convertToRgbaColor(*color);
+      gtk_color_chooser_set_rgba(GTK_COLOR_CHOOSER(color_chooser), &color_rgba);
+    }
+  }
+
+  // The initial color needs to be set last.
+  GdkRGBA color_rgba = convertToRgbaColor(color);
+  gtk_color_chooser_set_rgba(GTK_COLOR_CHOOSER(color_chooser), &color_rgba);
+
+  g_signal_connect(GTK_COLOR_CHOOSER(color_chooser), "color-activated",
+                   G_CALLBACK(OnColorChanged), this);
+#else
+  GtkWidget* color_chooser = gtk_color_selection_dialog_new(title.get());
+
+  if (parent_window) {
+    GtkWindow* window = GTK_WINDOW(color_chooser);
+    gtk_window_set_transient_for(window, parent_window);
+    gtk_window_set_destroy_with_parent(window, TRUE);
+    if (gtk_window_get_modal(parent_window)) {
+      gtk_window_set_modal(window, TRUE);
+    }
+  }
+
+  GdkColor color_gdk = convertToGdkColor(color);
+  gtk_color_selection_set_current_color(WidgetGetColorSelection(color_chooser),
+                                        &color_gdk);
+
+  g_signal_connect(WidgetGetColorSelection(color_chooser), "color-changed",
+                   G_CALLBACK(OnColorChanged), this);
+#endif
+
+  NS_ADDREF_THIS();
+
+  g_signal_connect(color_chooser, "response", G_CALLBACK(OnResponse), this);
+  g_signal_connect(color_chooser, "destroy", G_CALLBACK(OnDestroy), this);
+  gtk_widget_show(color_chooser);
+
+  return NS_OK;
+}
+
+#if defined(ACTIVATE_GTK3_COLOR_PICKER)
+/* static */
+void nsColorPicker::OnColorChanged(GtkColorChooser* color_chooser,
+                                   GdkRGBA* color, gpointer user_data) {
+  static_cast<nsColorPicker*>(user_data)->Update(color);
+}
+
+void nsColorPicker::Update(GdkRGBA* color) {
+  SetColor(color);
+  if (mCallback) {
+    mCallback->Update(mColor);
+  }
+}
+
+void nsColorPicker::SetColor(const GdkRGBA* color) {
+  mColor.Assign('#');
+  mColor += ToHexString(convertGdkRgbaComponent(color->red));
+  mColor += ToHexString(convertGdkRgbaComponent(color->green));
+  mColor += ToHexString(convertGdkRgbaComponent(color->blue));
+}
+#else
+/* static */
+void nsColorPicker::OnColorChanged(GtkColorSelection* colorselection,
+                                   gpointer user_data) {
+  static_cast<nsColorPicker*>(user_data)->Update(colorselection);
+}
+
+void nsColorPicker::Update(GtkColorSelection* colorselection) {
+  ReadValueFromColorSelection(colorselection);
+  if (mCallback) {
+    mCallback->Update(mColor);
+  }
+}
+
+void nsColorPicker::ReadValueFromColorSelection(
+    GtkColorSelection* colorselection) {
+  GdkColor rgba;
+  gtk_color_selection_get_current_color(colorselection, &rgba);
+
+  mColor.Assign('#');
+  mColor += ToHexString(convertGdkColorComponent(rgba.red));
+  mColor += ToHexString(convertGdkColorComponent(rgba.green));
+  mColor += ToHexString(convertGdkColorComponent(rgba.blue));
+}
+#endif
+
+/* static */
+void nsColorPicker::OnResponse(GtkWidget* color_chooser, gint response_id,
+                               gpointer user_data) {
+  static_cast<nsColorPicker*>(user_data)->Done(color_chooser, response_id);
+}
+
+/* static */
+void nsColorPicker::OnDestroy(GtkWidget* color_chooser, gpointer user_data) {
+  static_cast<nsColorPicker*>(user_data)->Done(color_chooser,
+                                               GTK_RESPONSE_CANCEL);
+}
+
+void nsColorPicker::Done(GtkWidget* color_chooser, gint response) {
+  switch (response) {
+    case GTK_RESPONSE_OK:
+    case GTK_RESPONSE_ACCEPT:
+#if defined(ACTIVATE_GTK3_COLOR_PICKER)
+      GdkRGBA color;
+      gtk_color_chooser_get_rgba(GTK_COLOR_CHOOSER(color_chooser), &color);
+      SetColor(&color);
+#else
+      ReadValueFromColorSelection(WidgetGetColorSelection(color_chooser));
+#endif
+      break;
+    case GTK_RESPONSE_CANCEL:
+    case GTK_RESPONSE_CLOSE:
+    case GTK_RESPONSE_DELETE_EVENT:
+      mColor = mInitialColor;
+      break;
+    default:
+      NS_WARNING("Unexpected response");
+      break;
+  }
+
+  // A "response" signal won't be sent again but "destroy" will be.
+  g_signal_handlers_disconnect_by_func(color_chooser, FuncToGpointer(OnDestroy),
+                                       this);
+
+  gtk_widget_destroy(color_chooser);
+  if (mCallback) {
+    mCallback->Done(mColor);
+    mCallback = nullptr;
+  }
+
+  NS_RELEASE_THIS();
+}
+
+nsString nsColorPicker::ToHexString(int n) {
+  nsString result;
+  if (n <= 0x0F) {
+    result.Append('0');
+  }
+  result.AppendInt(n, 16);
+  return result;
+}
diff --git a/widget/gtk/nsColorPicker.h b/widget/gtk/nsColorPicker.h
new file mode 100644
index 0000000000..d693175717
--- /dev/null
+++ b/widget/gtk/nsColorPicker.h
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsColorPicker_h__
+#define nsColorPicker_h__
+
+#include <gtk/gtk.h>
+
+#include "nsCOMPtr.h"
+#include "nsIColorPicker.h"
+#include "nsString.h"
+
+// Enable Gtk3 system color picker.
+#define ACTIVATE_GTK3_COLOR_PICKER 1
+
+class nsIWidget;
+
+class nsColorPicker final : public nsIColorPicker {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSICOLORPICKER
+
+  nsColorPicker() = default;
+
+ private:
+  ~nsColorPicker() = default;
+
+  static nsString ToHexString(int n);
+
+  static void OnResponse(GtkWidget* dialog, gint response_id,
+                         gpointer user_data);
+  static void OnDestroy(GtkWidget* dialog, gpointer user_data);
+
+#if defined(ACTIVATE_GTK3_COLOR_PICKER)
+  static void OnColorChanged(GtkColorChooser* color_chooser, GdkRGBA* color,
+                             gpointer user_data);
+
+  static int convertGdkRgbaComponent(gdouble color_component);
+  static gdouble convertToGdkRgbaComponent(int color_component);
+  static GdkRGBA convertToRgbaColor(nscolor color);
+
+  void Update(GdkRGBA* color);
+  void SetColor(const GdkRGBA* color);
+#else
+  static void OnColorChanged(GtkColorSelection* colorselection,
+                             gpointer user_data);
+
+  // Conversion functions for color
+  static int convertGdkColorComponent(guint16 color_component);
+  static guint16 convertToGdkColorComponent(int color_component);
+  static GdkColor convertToGdkColor(nscolor color);
+
+  static GtkColorSelection* WidgetGetColorSelection(GtkWidget* widget);
+
+  void Update(GtkColorSelection* colorselection);
+  void ReadValueFromColorSelection(GtkColorSelection* colorselection);
+#endif
+
+  void Done(GtkWidget* dialog, gint response_id);
+
+  nsCOMPtr<nsIWidget> mParentWidget;
+  nsCOMPtr<nsIColorPickerShownCallback> mCallback;
+  nsString mTitle;
+  nsString mColor;
+  nsString mInitialColor;
+  nsTArray<nsString> mDefaultColors;
+};
+
+#endif  // nsColorPicker_h__
diff --git a/widget/gtk/nsDeviceContextSpecG.cpp b/widget/gtk/nsDeviceContextSpecG.cpp
new file mode 100644
index 0000000000..3dfa816408
--- /dev/null
+++ b/widget/gtk/nsDeviceContextSpecG.cpp
@@ -0,0 +1,422 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsDeviceContextSpecG.h"
+
+#include "mozilla/gfx/PrintPromise.h"
+#include "mozilla/gfx/PrintTargetPDF.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Services.h"
+#include "mozilla/GUniquePtr.h"
+#include "mozilla/WidgetUtilsGtk.h"
+
+#include "prenv.h" /* for PR_GetEnv */
+
+#include "nsComponentManagerUtils.h"
+#include "nsIObserverService.h"
+#include "nsPrintfCString.h"
+#include "nsQueryObject.h"
+#include "nsReadableUtils.h"
+#include "nsThreadUtils.h"
+
+#include "nsCUPSShim.h"
+#include "nsPrinterCUPS.h"
+
+#include "nsPrintSettingsGTK.h"
+
+#include "nsIFileStreams.h"
+#include "nsIFile.h"
+#include "nsTArray.h"
+#include "nsThreadUtils.h"
+
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_print.h"
+
+#include <dlfcn.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+// To check if we need to use flatpak portal for printing
+#include "nsIGIOService.h"
+
+using namespace mozilla;
+
+using mozilla::gfx::IntSize;
+using mozilla::gfx::PrintEndDocumentPromise;
+using mozilla::gfx::PrintTarget;
+using mozilla::gfx::PrintTargetPDF;
+
+nsDeviceContextSpecGTK::nsDeviceContextSpecGTK()
+    : mGtkPrintSettings(nullptr), mGtkPageSetup(nullptr) {}
+
+nsDeviceContextSpecGTK::~nsDeviceContextSpecGTK() {
+  if (mGtkPageSetup) {
+    g_object_unref(mGtkPageSetup);
+  }
+
+  if (mGtkPrintSettings) {
+    g_object_unref(mGtkPrintSettings);
+  }
+
+  if (mSpoolFile) {
+    mSpoolFile->Remove(false);
+  }
+}
+
+NS_IMPL_ISUPPORTS(nsDeviceContextSpecGTK, nsIDeviceContextSpec)
+
+already_AddRefed<PrintTarget> nsDeviceContextSpecGTK::MakePrintTarget() {
+  double width, height;
+  mPrintSettings->GetEffectiveSheetSize(&width, &height);
+
+  // convert twips to points
+  width /= TWIPS_PER_POINT_FLOAT;
+  height /= TWIPS_PER_POINT_FLOAT;
+
+  // We shouldn't be attempting to get a surface if we've already got a spool
+  // file.
+  MOZ_ASSERT(!mSpoolFile);
+
+  auto stream = [&]() -> nsCOMPtr<nsIOutputStream> {
+    if (mPrintSettings->GetOutputDestination() ==
+        nsIPrintSettings::kOutputDestinationStream) {
+      nsCOMPtr<nsIOutputStream> out;
+      mPrintSettings->GetOutputStream(getter_AddRefs(out));
+      return out;
+    }
+    // Spool file. Use Glib's temporary file function since we're
+    // already dependent on the gtk software stack.
+    gchar* buf;
+    gint fd = g_file_open_tmp("XXXXXX.tmp", &buf, nullptr);
+    if (-1 == fd) {
+      return nullptr;
+    }
+    close(fd);
+    if (NS_FAILED(NS_NewNativeLocalFile(nsDependentCString(buf), false,
+                                        getter_AddRefs(mSpoolFile)))) {
+      unlink(buf);
+      g_free(buf);
+      return nullptr;
+    }
+    mSpoolName = buf;
+    g_free(buf);
+    mSpoolFile->SetPermissions(0600);
+    nsCOMPtr<nsIFileOutputStream> stream =
+        do_CreateInstance("@mozilla.org/network/file-output-stream;1");
+    if (NS_FAILED(stream->Init(mSpoolFile, -1, -1, 0))) {
+      return nullptr;
+    }
+    return stream;
+  }();
+
+  return PrintTargetPDF::CreateOrNull(stream, IntSize::Ceil(width, height));
+}
+
+#define DECLARE_KNOWN_MONOCHROME_SETTING(key_, value_) {"cups-" key_, value_},
+
+struct {
+  const char* mKey;
+  const char* mValue;
+} kKnownMonochromeSettings[] = {
+    CUPS_EACH_MONOCHROME_PRINTER_SETTING(DECLARE_KNOWN_MONOCHROME_SETTING)};
+
+#undef DECLARE_KNOWN_MONOCHROME_SETTING
+
+// https://developer.gnome.org/gtk3/stable/GtkPaperSize.html#gtk-paper-size-new-from-ipp
+static GUniquePtr<GtkPaperSize> GtkPaperSizeFromIpp(const gchar* aIppName,
+                                                    gdouble aWidth,
+                                                    gdouble aHeight) {
+  static auto sPtr = (GtkPaperSize * (*)(const gchar*, gdouble, gdouble))
+      dlsym(RTLD_DEFAULT, "gtk_paper_size_new_from_ipp");
+  if (gtk_check_version(3, 16, 0)) {
+    return nullptr;
+  }
+  return GUniquePtr<GtkPaperSize>(sPtr(aIppName, aWidth, aHeight));
+}
+
+static bool PaperSizeAlmostEquals(GtkPaperSize* aSize,
+                                  GtkPaperSize* aOtherSize) {
+  const double kEpsilon = 1.0;  // millimetres
+  // GTK stores sizes internally in millimetres so just use that.
+  if (fabs(gtk_paper_size_get_height(aSize, GTK_UNIT_MM) -
+           gtk_paper_size_get_height(aOtherSize, GTK_UNIT_MM)) > kEpsilon) {
+    return false;
+  }
+  if (fabs(gtk_paper_size_get_width(aSize, GTK_UNIT_MM) -
+           gtk_paper_size_get_width(aOtherSize, GTK_UNIT_MM)) > kEpsilon) {
+    return false;
+  }
+  return true;
+}
+
+// Prefer the ppd name because some printers don't deal well even with standard
+// ipp names.
+static GUniquePtr<GtkPaperSize> PpdSizeFromIppName(const gchar* aIppName) {
+  static constexpr struct {
+    const char* mCups;
+    const char* mGtk;
+  } kMap[] = {
+      {CUPS_MEDIA_A3, GTK_PAPER_NAME_A3},
+      {CUPS_MEDIA_A4, GTK_PAPER_NAME_A4},
+      {CUPS_MEDIA_A5, GTK_PAPER_NAME_A5},
+      {CUPS_MEDIA_LETTER, GTK_PAPER_NAME_LETTER},
+      {CUPS_MEDIA_LEGAL, GTK_PAPER_NAME_LEGAL},
+      // Other gtk sizes with no standard CUPS constant: _EXECUTIVE and _B5
+  };
+
+  for (const auto& entry : kMap) {
+    if (!strcmp(entry.mCups, aIppName)) {
+      return GUniquePtr<GtkPaperSize>(gtk_paper_size_new(entry.mGtk));
+    }
+  }
+
+  return nullptr;
+}
+
+// This is a horrible workaround for some printer driver bugs that treat custom
+// page sizes different to standard ones. If our paper object matches one of a
+// standard one, use a standard paper size object instead.
+//
+// We prefer ppd to ipp to custom sizes.
+//
+// See bug 414314, bug 1691798, and bug 1717292 for more info.
+static GUniquePtr<GtkPaperSize> GetStandardGtkPaperSize(
+    GtkPaperSize* aGeckoPaperSize) {
+  // We should get an ipp name from cups, try to get a ppd from that first.
+  const gchar* geckoName = gtk_paper_size_get_name(aGeckoPaperSize);
+  if (auto ppd = PpdSizeFromIppName(geckoName)) {
+    return ppd;
+  }
+
+  // We try gtk_paper_size_new_from_ipp next, because even though
+  // gtk_paper_size_new tries to deal with ipp, it has some rounding issues that
+  // the ipp equivalent doesn't have, see
+  // https://gitlab.gnome.org/GNOME/gtk/-/issues/3685.
+  if (auto ipp = GtkPaperSizeFromIpp(
+          geckoName, gtk_paper_size_get_width(aGeckoPaperSize, GTK_UNIT_POINTS),
+          gtk_paper_size_get_height(aGeckoPaperSize, GTK_UNIT_POINTS))) {
+    if (!gtk_paper_size_is_custom(ipp.get())) {
+      if (auto ppd = PpdSizeFromIppName(gtk_paper_size_get_name(ipp.get()))) {
+        return ppd;
+      }
+      return ipp;
+    }
+  }
+
+  GUniquePtr<GtkPaperSize> size(gtk_paper_size_new(geckoName));
+  // gtk_paper_size_is_equal compares just paper names. The name in Gecko
+  // might come from CUPS, which is an ipp size, and gets normalized by gtk.
+  // So check also for the same actual paper size.
+  if (gtk_paper_size_is_equal(size.get(), aGeckoPaperSize) ||
+      PaperSizeAlmostEquals(aGeckoPaperSize, size.get())) {
+    return size;
+  }
+
+  // Not the same after all, so use our custom paper sizes instead.
+  return nullptr;
+}
+
+/** -------------------------------------------------------
+ *  Initialize the nsDeviceContextSpecGTK
+ *  @update   dc 2/15/98
+ *  @update   syd 3/2/99
+ */
+NS_IMETHODIMP nsDeviceContextSpecGTK::Init(nsIPrintSettings* aPS,
+                                           bool aIsPrintPreview) {
+  RefPtr<nsPrintSettingsGTK> settings = do_QueryObject(aPS);
+  if (!settings) {
+    return NS_ERROR_NO_INTERFACE;
+  }
+  mPrintSettings = aPS;
+
+  mGtkPrintSettings = settings->GetGtkPrintSettings();
+  mGtkPageSetup = settings->GetGtkPageSetup();
+
+  GtkPaperSize* geckoPaperSize = gtk_page_setup_get_paper_size(mGtkPageSetup);
+  GUniquePtr<GtkPaperSize> gtkPaperSize =
+      GetStandardGtkPaperSize(geckoPaperSize);
+
+  mGtkPageSetup = gtk_page_setup_copy(mGtkPageSetup);
+  mGtkPrintSettings = gtk_print_settings_copy(mGtkPrintSettings);
+
+  if (!aPS->GetPrintInColor() && StaticPrefs::print_cups_monochrome_enabled()) {
+    for (const auto& setting : kKnownMonochromeSettings) {
+      gtk_print_settings_set(mGtkPrintSettings, setting.mKey, setting.mValue);
+    }
+    auto applySetting = [&](const nsACString& aKey, const nsACString& aVal) {
+      nsAutoCString extra;
+      extra.AppendASCII("cups-");
+      extra.Append(aKey);
+      gtk_print_settings_set(mGtkPrintSettings, extra.get(),
+                             nsAutoCString(aVal).get());
+    };
+    nsPrinterCUPS::ForEachExtraMonochromeSetting(applySetting);
+  }
+
+  GtkPaperSize* properPaperSize =
+      gtkPaperSize ? gtkPaperSize.get() : geckoPaperSize;
+  gtk_print_settings_set_paper_size(mGtkPrintSettings, properPaperSize);
+  gtk_page_setup_set_paper_size_and_default_margins(mGtkPageSetup,
+                                                    properPaperSize);
+  return NS_OK;
+}
+
+static void print_callback(GtkPrintJob* aJob, gpointer aData,
+                           const GError* aError) {
+  g_object_unref(aJob);
+  ((nsIFile*)aData)->Remove(false);
+}
+
+/* static */
+gboolean nsDeviceContextSpecGTK::PrinterEnumerator(GtkPrinter* aPrinter,
+                                                   gpointer aData) {
+  nsDeviceContextSpecGTK* spec = (nsDeviceContextSpecGTK*)aData;
+
+  if (spec->mHasEnumerationFoundAMatch) {
+    // We're already done, but we're letting the enumeration run its course,
+    // to avoid a GTK bug.
+    return FALSE;
+  }
+
+  // Find the printer whose name matches the one inside the settings.
+  nsString printerName;
+  nsresult rv = spec->mPrintSettings->GetPrinterName(printerName);
+  if (NS_SUCCEEDED(rv) && !printerName.IsVoid()) {
+    NS_ConvertUTF16toUTF8 requestedName(printerName);
+    const char* currentName = gtk_printer_get_name(aPrinter);
+    if (requestedName.Equals(currentName)) {
+      nsPrintSettingsGTK::From(spec->mPrintSettings)->SetGtkPrinter(aPrinter);
+
+      // Bug 1145916 - attempting to kick off a print job for this printer
+      // during this tick of the event loop will result in the printer backend
+      // misunderstanding what the capabilities of the printer are due to a
+      // GTK bug (https://bugzilla.gnome.org/show_bug.cgi?id=753041). We
+      // sidestep this by deferring the print to the next tick.
+      NS_DispatchToCurrentThread(
+          NewRunnableMethod("nsDeviceContextSpecGTK::StartPrintJob", spec,
+                            &nsDeviceContextSpecGTK::StartPrintJob));
+
+      // We're already done, but we need to let the enumeration run its course,
+      // to avoid a GTK bug. So we record that we've found a match and
+      // then return FALSE.
+      // TODO: If/when we can be sure that GTK handles this OK, we could
+      // return TRUE to avoid some needless enumeration.
+      spec->mHasEnumerationFoundAMatch = true;
+      return FALSE;
+    }
+  }
+
+  // We haven't found it yet - keep searching...
+  return FALSE;
+}
+
+void nsDeviceContextSpecGTK::StartPrintJob() {
+  GtkPrintJob* job = gtk_print_job_new(
+      mTitle.get(), nsPrintSettingsGTK::From(mPrintSettings)->GetGtkPrinter(),
+      mGtkPrintSettings, mGtkPageSetup);
+
+  if (!gtk_print_job_set_source_file(job, mSpoolName.get(), nullptr)) return;
+
+  // Now gtk owns the print job, and will be released via our callback.
+  gtk_print_job_send(job, print_callback, mSpoolFile.forget().take(),
+                     [](gpointer aData) {
+                       auto* spoolFile = static_cast<nsIFile*>(aData);
+                       NS_RELEASE(spoolFile);
+                     });
+}
+
+void nsDeviceContextSpecGTK::EnumeratePrinters() {
+  mHasEnumerationFoundAMatch = false;
+  gtk_enumerate_printers(&nsDeviceContextSpecGTK::PrinterEnumerator, this,
+                         nullptr, TRUE);
+}
+
+NS_IMETHODIMP
+nsDeviceContextSpecGTK::BeginDocument(const nsAString& aTitle,
+                                      const nsAString& aPrintToFileName,
+                                      int32_t aStartPage, int32_t aEndPage) {
+  // Print job names exceeding 255 bytes are safe with GTK version 3.18.2 or
+  // newer. This is a workaround for old GTK.
+  if (gtk_check_version(3, 18, 2) != nullptr) {
+    PrintTarget::AdjustPrintJobNameForIPP(aTitle, mTitle);
+  } else {
+    CopyUTF16toUTF8(aTitle, mTitle);
+  }
+
+  return NS_OK;
+}
+
+RefPtr<PrintEndDocumentPromise> nsDeviceContextSpecGTK::EndDocument() {
+  switch (mPrintSettings->GetOutputDestination()) {
+    case nsIPrintSettings::kOutputDestinationPrinter: {
+      // At this point, we might have a GtkPrinter set up in nsPrintSettingsGTK,
+      // or we might not. In the single-process case, we probably will, as this
+      // is populated by the print settings dialog, or set to the default
+      // printer.
+      // In the multi-process case, we proxy the print settings dialog over to
+      // the parent process, and only get the name of the printer back on the
+      // content process side. In that case, we need to enumerate the printers
+      // on the content side, and find a printer with a matching name.
+
+      if (nsPrintSettingsGTK::From(mPrintSettings)->GetGtkPrinter()) {
+        // We have a printer, so we can print right away.
+        StartPrintJob();
+      } else {
+        // We don't have a printer. We have to enumerate the printers and find
+        // one with a matching name.
+        NS_DispatchToCurrentThread(
+            NewRunnableMethod("nsDeviceContextSpecGTK::EnumeratePrinters", this,
+                              &nsDeviceContextSpecGTK::EnumeratePrinters));
+      }
+      break;
+    }
+    case nsIPrintSettings::kOutputDestinationFile: {
+      // Handle print-to-file ourselves for the benefit of embedders
+      nsString targetPath;
+      nsCOMPtr<nsIFile> destFile;
+      mPrintSettings->GetToFileName(targetPath);
+
+      nsresult rv =
+          NS_NewLocalFile(targetPath, false, getter_AddRefs(destFile));
+      if (NS_FAILED(rv)) {
+        return PrintEndDocumentPromise::CreateAndReject(rv, __func__);
+      }
+
+      return nsIDeviceContextSpec::EndDocumentAsync(
+          __func__,
+          [destFile = std::move(destFile),
+           spoolFile = std::move(mSpoolFile)]() -> nsresult {
+            nsAutoString destLeafName;
+            auto rv = destFile->GetLeafName(destLeafName);
+            NS_ENSURE_SUCCESS(rv, rv);
+
+            nsCOMPtr<nsIFile> destDir;
+            rv = destFile->GetParent(getter_AddRefs(destDir));
+            NS_ENSURE_SUCCESS(rv, rv);
+
+            rv = spoolFile->MoveTo(destDir, destLeafName);
+            NS_ENSURE_SUCCESS(rv, rv);
+
+            // This is the standard way to get the UNIX umask. Ugh.
+            mode_t mask = umask(0);
+            umask(mask);
+            // If you're not familiar with umasks, they contain the bits of what
+            // NOT to set in the permissions (thats because files and
+            // directories have different numbers of bits for their permissions)
+            destFile->SetPermissions(0666 & ~(mask));
+            return NS_OK;
+          });
+
+      break;
+    }
+    case nsIPrintSettings::kOutputDestinationStream:
+      // Nothing to do, handled in MakePrintTarget.
+      MOZ_ASSERT(!mSpoolFile);
+      break;
+  }
+  return PrintEndDocumentPromise::CreateAndResolve(true, __func__);
+}
diff --git a/widget/gtk/nsDeviceContextSpecG.h b/widget/gtk/nsDeviceContextSpecG.h
new file mode 100644
index 0000000000..df5552c36c
--- /dev/null
+++ b/widget/gtk/nsDeviceContextSpecG.h
@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsDeviceContextSpecGTK_h___
+#define nsDeviceContextSpecGTK_h___
+
+struct JSContext;
+
+#include "nsIDeviceContextSpec.h"
+#include "nsIPrinterList.h"
+#include "nsIPrintSettings.h"
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/gfx/PrintPromise.h"
+
+#include "nsCRT.h" /* should be <limits.h>? */
+
+#include <gtk/gtk.h>
+#include <gtk/gtkunixprint.h>
+
+#define NS_PORTRAIT 0
+#define NS_LANDSCAPE 1
+
+class nsPrintSettingsGTK;
+
+class nsDeviceContextSpecGTK : public nsIDeviceContextSpec {
+ public:
+  nsDeviceContextSpecGTK();
+
+  NS_DECL_ISUPPORTS
+
+  already_AddRefed<PrintTarget> MakePrintTarget() final;
+
+  NS_IMETHOD Init(nsIPrintSettings* aPS, bool aIsPrintPreview) override;
+  NS_IMETHOD BeginDocument(const nsAString& aTitle,
+                           const nsAString& aPrintToFileName,
+                           int32_t aStartPage, int32_t aEndPage) override;
+  RefPtr<mozilla::gfx::PrintEndDocumentPromise> EndDocument() override;
+  NS_IMETHOD BeginPage(const IntSize& aSizeInPoints) override { return NS_OK; }
+  NS_IMETHOD EndPage() override { return NS_OK; }
+
+ protected:
+  virtual ~nsDeviceContextSpecGTK();
+  GtkPrintSettings* mGtkPrintSettings;
+  GtkPageSetup* mGtkPageSetup;
+
+  nsCString mSpoolName;
+  nsCOMPtr<nsIFile> mSpoolFile;
+  nsCString mTitle;
+  // Helper for EnumeratePrinters / PrinterEnumerator:
+  bool mHasEnumerationFoundAMatch = false;
+
+ private:
+  void EnumeratePrinters();
+  void StartPrintJob();
+  static gboolean PrinterEnumerator(GtkPrinter* aPrinter, gpointer aData);
+};
+
+#endif /* !nsDeviceContextSpecGTK_h___ */
diff --git a/widget/gtk/nsDragService.cpp b/widget/gtk/nsDragService.cpp
new file mode 100644
index 0000000000..df0965b5e4
--- /dev/null
+++ b/widget/gtk/nsDragService.cpp
@@ -0,0 +1,2756 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=4 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsDragService.h"
+#include "nsArrayUtils.h"
+#include "nsIObserverService.h"
+#include "nsWidgetsCID.h"
+#include "nsWindow.h"
+#include "nsSystemInfo.h"
+#include "nsXPCOM.h"
+#include "nsICookieJarSettings.h"
+#include "nsISupportsPrimitives.h"
+#include "nsIIOService.h"
+#include "nsIFileURL.h"
+#include "nsNetUtil.h"
+#include "mozilla/Logging.h"
+#include "nsTArray.h"
+#include "nsPrimitiveHelpers.h"
+#include "prtime.h"
+#include "prthread.h"
+#include <dlfcn.h>
+#include <gtk/gtk.h>
+#include "nsCRT.h"
+#include "mozilla/BasicEvents.h"
+#include "mozilla/Services.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/WidgetUtilsGtk.h"
+#include "GRefPtr.h"
+#include "nsAppShell.h"
+
+#ifdef MOZ_X11
+#  include "gfxXlibSurface.h"
+#endif
+#include "gfxContext.h"
+#include "nsImageToPixbuf.h"
+#include "nsPresContext.h"
+#include "nsIContent.h"
+#include "mozilla/dom/Document.h"
+#include "nsViewManager.h"
+#include "nsIFrame.h"
+#include "nsGtkUtils.h"
+#include "nsGtkKeyUtils.h"
+#include "mozilla/gfx/2D.h"
+#include "gfxPlatform.h"
+#include "ScreenHelperGTK.h"
+#include "nsArrayUtils.h"
+#include "nsStringStream.h"
+#include "nsDirectoryService.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsEscape.h"
+#include "nsString.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+
+//  The maximum time to wait for a "drag_received" arrived in microseconds.
+#define NS_DND_TIMEOUT 1000000
+
+//  The maximum time to wait before temporary files resulting
+//  from drag'n'drop events will be removed in miliseconds.
+//  It's set to 5 min as the file has to be present some time after drop
+//  event to give target application time to get the data.
+//  (A target application can throw a dialog to ask user what to do with
+//  the data and will access the tmp file after user action.)
+#define NS_DND_TMP_CLEANUP_TIMEOUT (1000 * 60 * 5)
+
+#define NS_SYSTEMINFO_CONTRACTID "@mozilla.org/system-info;1"
+
+// This sets how opaque the drag image is
+#define DRAG_IMAGE_ALPHA_LEVEL 0.5
+
+#ifdef MOZ_LOGGING
+extern mozilla::LazyLogModule gWidgetDragLog;
+#  define LOGDRAGSERVICE(str, ...)                    \
+    MOZ_LOG(gWidgetDragLog, mozilla::LogLevel::Debug, \
+            ("[Depth %d]: " str, GetLoopDepth(), ##__VA_ARGS__))
+#  define LOGDRAGSERVICESTATIC(str, ...) \
+    MOZ_LOG(gWidgetDragLog, mozilla::LogLevel::Debug, (str, ##__VA_ARGS__))
+#else
+#  define LOGDRAGSERVICE(...)
+#endif
+
+// Helper class to block native events processing.
+class MOZ_STACK_CLASS AutoSuspendNativeEvents {
+ public:
+  AutoSuspendNativeEvents() {
+    mAppShell = do_GetService(NS_APPSHELL_CID);
+    mAppShell->SuspendNative();
+  }
+  ~AutoSuspendNativeEvents() { mAppShell->ResumeNative(); }
+
+ private:
+  nsCOMPtr<nsIAppShell> mAppShell;
+};
+
+// data used for synthetic periodic motion events sent to the source widget
+// grabbing real events for the drag.
+static guint sMotionEventTimerID;
+
+static GdkEvent* sMotionEvent;
+static GUniquePtr<GdkEvent> TakeMotionEvent() {
+  GUniquePtr<GdkEvent> event(sMotionEvent);
+  sMotionEvent = nullptr;
+  return event;
+}
+static void SetMotionEvent(GUniquePtr<GdkEvent> aEvent) {
+  TakeMotionEvent();
+  sMotionEvent = aEvent.release();
+}
+
+static GtkWidget* sGrabWidget;
+
+static constexpr nsLiteralString kDisallowedExportedSchemes[] = {
+    u"about"_ns,          u"blob"_ns,        u"cached-favicon"_ns,
+    u"chrome"_ns,         u"imap"_ns,        u"javascript"_ns,
+    u"mailbox"_ns,        u"news"_ns,        u"page-icon"_ns,
+    u"resource"_ns,       u"view-source"_ns, u"moz-extension"_ns,
+    u"moz-page-thumb"_ns,
+};
+
+// _NETSCAPE_URL is similar to text/uri-list type.
+// Format is UTF8: URL + "\n" + title.
+// While text/uri-list tells target application to fetch, copy and store data
+// from URL, _NETSCAPE_URL suggest to create a link to the target.
+// Also _NETSCAPE_URL points to only one item while text/uri-list can point to
+// multiple ones.
+static const char gMozUrlType[] = "_NETSCAPE_URL";
+static const char gMimeListType[] = "application/x-moz-internal-item-list";
+static const char gTextUriListType[] = "text/uri-list";
+static const char gTextPlainUTF8Type[] = "text/plain;charset=utf-8";
+static const char gXdndDirectSaveType[] = "XdndDirectSave0";
+static const char gTabDropType[] = "application/x-moz-tabbrowser-tab";
+static const char gPortalFile[] = "application/vnd.portal.files";
+static const char gPortalFileTransfer[] = "application/vnd.portal.filetransfer";
+
+// See https://docs.gtk.org/gtk3/enum.DragResult.html
+static const char kGtkDragResults[][100]{
+    "GTK_DRAG_RESULT_SUCCESS",        "GTK_DRAG_RESULT_NO_TARGET",
+    "GTK_DRAG_RESULT_USER_CANCELLED", "GTK_DRAG_RESULT_TIMEOUT_EXPIRED",
+    "GTK_DRAG_RESULT_GRAB_BROKEN",    "GTK_DRAG_RESULT_ERROR"};
+
+static void invisibleSourceDragBegin(GtkWidget* aWidget,
+                                     GdkDragContext* aContext, gpointer aData);
+
+static void invisibleSourceDragEnd(GtkWidget* aWidget, GdkDragContext* aContext,
+                                   gpointer aData);
+
+static gboolean invisibleSourceDragFailed(GtkWidget* aWidget,
+                                          GdkDragContext* aContext,
+                                          gint aResult, gpointer aData);
+
+static void invisibleSourceDragDataGet(GtkWidget* aWidget,
+                                       GdkDragContext* aContext,
+                                       GtkSelectionData* aSelectionData,
+                                       guint aInfo, guint32 aTime,
+                                       gpointer aData);
+
+nsDragService::nsDragService()
+    : mScheduledTask(eDragTaskNone),
+      mTaskSource(0),
+      mScheduledTaskIsRunning(false),
+      mCachedDragContext() {
+  // We have to destroy the hidden widget before the event loop stops
+  // running.
+  nsCOMPtr<nsIObserverService> obsServ =
+      mozilla::services::GetObserverService();
+  obsServ->AddObserver(this, "quit-application", false);
+
+  // our hidden source widget
+  // Using an offscreen window works around bug 983843.
+  mHiddenWidget = gtk_offscreen_window_new();
+  // make sure that the widget is realized so that
+  // we can use it as a drag source.
+  gtk_widget_realize(mHiddenWidget);
+  // hook up our internal signals so that we can get some feedback
+  // from our drag source
+  g_signal_connect(mHiddenWidget, "drag_begin",
+                   G_CALLBACK(invisibleSourceDragBegin), this);
+  g_signal_connect(mHiddenWidget, "drag_data_get",
+                   G_CALLBACK(invisibleSourceDragDataGet), this);
+  g_signal_connect(mHiddenWidget, "drag_end",
+                   G_CALLBACK(invisibleSourceDragEnd), this);
+  // drag-failed is available from GTK+ version 2.12
+  guint dragFailedID =
+      g_signal_lookup("drag-failed", G_TYPE_FROM_INSTANCE(mHiddenWidget));
+  if (dragFailedID) {
+    g_signal_connect_closure_by_id(
+        mHiddenWidget, dragFailedID, 0,
+        g_cclosure_new(G_CALLBACK(invisibleSourceDragFailed), this, nullptr),
+        FALSE);
+  }
+
+  // set up our logging module
+  mCanDrop = false;
+  mTargetDragDataReceived = false;
+  mTargetDragUris = nullptr;
+  mTargetDragData = 0;
+  mTargetDragDataLen = 0;
+  mTempFileTimerID = 0;
+  mEventLoopDepth = 0;
+  LOGDRAGSERVICE("nsDragService::nsDragService");
+}
+
+nsDragService::~nsDragService() {
+  LOGDRAGSERVICE("nsDragService::~nsDragService");
+  if (mTaskSource) g_source_remove(mTaskSource);
+  if (mTempFileTimerID) {
+    g_source_remove(mTempFileTimerID);
+    RemoveTempFiles();
+  }
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(nsDragService, nsBaseDragService, nsIObserver)
+
+mozilla::StaticRefPtr<nsDragService> sDragServiceInstance;
+/* static */
+already_AddRefed<nsDragService> nsDragService::GetInstance() {
+  if (gfxPlatform::IsHeadless()) {
+    return nullptr;
+  }
+  if (!sDragServiceInstance) {
+    sDragServiceInstance = new nsDragService();
+    ClearOnShutdown(&sDragServiceInstance);
+  }
+
+  RefPtr<nsDragService> service = sDragServiceInstance.get();
+  return service.forget();
+}
+
+// nsIObserver
+
+NS_IMETHODIMP
+nsDragService::Observe(nsISupports* aSubject, const char* aTopic,
+                       const char16_t* aData) {
+  if (!nsCRT::strcmp(aTopic, "quit-application")) {
+    LOGDRAGSERVICE("nsDragService::Observe(\"quit-application\")");
+    if (mHiddenWidget) {
+      gtk_widget_destroy(mHiddenWidget);
+      mHiddenWidget = 0;
+    }
+    TargetResetData();
+  } else {
+    MOZ_ASSERT_UNREACHABLE("unexpected topic");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  return NS_OK;
+}
+
+// Support for periodic drag events
+
+// http://www.whatwg.org/specs/web-apps/current-work/multipage/dnd.html#drag-and-drop-processing-model
+// and the Xdnd protocol both recommend that drag events are sent periodically,
+// but GTK does not normally provide this.
+//
+// Here GTK is periodically stimulated by copies of the most recent mouse
+// motion events so as to send drag position messages to the destination when
+// appropriate (after it has received a status event from the previous
+// message).
+//
+// (If events were sent only on the destination side then the destination
+// would have no message to which it could reply with a drag status.  Without
+// sending a drag status to the source, the destination would not be able to
+// change its feedback re whether it could accept the drop, and so the
+// source's behavior on drop will not be consistent.)
+
+static gboolean DispatchMotionEventCopy(gpointer aData) {
+  // Clear the timer id before OnSourceGrabEventAfter is called during event
+  // dispatch.
+  sMotionEventTimerID = 0;
+
+  GUniquePtr<GdkEvent> event = TakeMotionEvent();
+  // If there is no longer a grab on the widget, then the drag is over and
+  // there is no need to continue drag motion.
+  if (gtk_widget_has_grab(sGrabWidget)) {
+    gtk_propagate_event(sGrabWidget, event.get());
+  }
+
+  // Cancel this timer;
+  // We've already started another if the motion event was dispatched.
+  return FALSE;
+}
+
+static void OnSourceGrabEventAfter(GtkWidget* widget, GdkEvent* event,
+                                   gpointer user_data) {
+  // If there is no longer a grab on the widget, then the drag motion is
+  // over (though the data may not be fetched yet).
+  if (!gtk_widget_has_grab(sGrabWidget)) return;
+
+  if (event->type == GDK_MOTION_NOTIFY) {
+    SetMotionEvent(GUniquePtr<GdkEvent>(gdk_event_copy(event)));
+
+    // Update the cursor position.  The last of these recorded gets used for
+    // the eDragEnd event.
+    nsDragService* dragService = static_cast<nsDragService*>(user_data);
+    gint scale = mozilla::widget::ScreenHelperGTK::GetGTKMonitorScaleFactor();
+    auto p = LayoutDeviceIntPoint::Round(event->motion.x_root * scale,
+                                         event->motion.y_root * scale);
+    dragService->SetDragEndPoint(p);
+  } else if (sMotionEvent &&
+             (event->type == GDK_KEY_PRESS || event->type == GDK_KEY_RELEASE)) {
+    // Update modifier state from key events.
+    sMotionEvent->motion.state = event->key.state;
+  } else {
+    return;
+  }
+
+  if (sMotionEventTimerID) {
+    g_source_remove(sMotionEventTimerID);
+  }
+
+  // G_PRIORITY_DEFAULT_IDLE is lower priority than GDK's redraw idle source
+  // and lower than GTK's idle source that sends drag position messages after
+  // motion-notify signals.
+  //
+  // http://www.whatwg.org/specs/web-apps/current-work/multipage/dnd.html#drag-and-drop-processing-model
+  // recommends an interval of 350ms +/- 200ms.
+  sMotionEventTimerID = g_timeout_add_full(
+      G_PRIORITY_DEFAULT_IDLE, 350, DispatchMotionEventCopy, nullptr, nullptr);
+}
+
+static GtkWindow* GetGtkWindow(dom::Document* aDocument) {
+  if (!aDocument) return nullptr;
+
+  PresShell* presShell = aDocument->GetPresShell();
+  if (!presShell) {
+    return nullptr;
+  }
+
+  RefPtr<nsViewManager> vm = presShell->GetViewManager();
+  if (!vm) return nullptr;
+
+  nsCOMPtr<nsIWidget> widget = vm->GetRootWidget();
+  if (!widget) return nullptr;
+
+  GtkWidget* gtkWidget = static_cast<nsWindow*>(widget.get())->GetGtkWidget();
+  if (!gtkWidget) return nullptr;
+
+  GtkWidget* toplevel = nullptr;
+  toplevel = gtk_widget_get_toplevel(gtkWidget);
+  if (!GTK_IS_WINDOW(toplevel)) return nullptr;
+
+  return GTK_WINDOW(toplevel);
+}
+
+// nsIDragService
+
+NS_IMETHODIMP
+nsDragService::InvokeDragSession(
+    nsINode* aDOMNode, nsIPrincipal* aPrincipal, nsIContentSecurityPolicy* aCsp,
+    nsICookieJarSettings* aCookieJarSettings, nsIArray* aArrayTransferables,
+    uint32_t aActionType,
+    nsContentPolicyType aContentPolicyType = nsIContentPolicy::TYPE_OTHER) {
+  LOGDRAGSERVICE("nsDragService::InvokeDragSession");
+
+  // If the previous source drag has not yet completed, signal handlers need
+  // to be removed from sGrabWidget and dragend needs to be dispatched to
+  // the source node, but we can't call EndDragSession yet because we don't
+  // know whether or not the drag succeeded.
+  if (mSourceNode) return NS_ERROR_NOT_AVAILABLE;
+
+  return nsBaseDragService::InvokeDragSession(
+      aDOMNode, aPrincipal, aCsp, aCookieJarSettings, aArrayTransferables,
+      aActionType, aContentPolicyType);
+}
+
+// nsBaseDragService
+nsresult nsDragService::InvokeDragSessionImpl(
+    nsIArray* aArrayTransferables, const Maybe<CSSIntRegion>& aRegion,
+    uint32_t aActionType) {
+  // make sure that we have an array of transferables to use
+  if (!aArrayTransferables) return NS_ERROR_INVALID_ARG;
+  // set our reference to the transferables.  this will also addref
+  // the transferables since we're going to hang onto this beyond the
+  // length of this call
+  mSourceDataItems = aArrayTransferables;
+
+  LOGDRAGSERVICE("nsDragService::InvokeDragSessionImpl");
+
+  GdkDevice* device = widget::GdkGetPointer();
+  GdkWindow* originGdkWindow = nullptr;
+  if (widget::GdkIsWaylandDisplay() || widget::IsXWaylandProtocol()) {
+    originGdkWindow =
+        gdk_device_get_window_at_position(device, nullptr, nullptr);
+    // Workaround for https://gitlab.gnome.org/GNOME/gtk/-/issues/6385
+    // Check we have GdkWindow drag source.
+    if (!originGdkWindow) {
+      NS_WARNING(
+          "nsDragService::InvokeDragSessionImpl(): Missing origin GdkWindow!");
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  // get the list of items we offer for drags
+  GtkTargetList* sourceList = GetSourceList();
+
+  if (!sourceList) return NS_OK;
+
+  // save our action type
+  GdkDragAction action = GDK_ACTION_DEFAULT;
+
+  if (aActionType & DRAGDROP_ACTION_COPY)
+    action = (GdkDragAction)(action | GDK_ACTION_COPY);
+  if (aActionType & DRAGDROP_ACTION_MOVE)
+    action = (GdkDragAction)(action | GDK_ACTION_MOVE);
+  if (aActionType & DRAGDROP_ACTION_LINK)
+    action = (GdkDragAction)(action | GDK_ACTION_LINK);
+
+  GdkEvent* existingEvent = widget::GetLastMousePressEvent();
+  GdkEvent fakeEvent;
+  if (!existingEvent) {
+    // Create a fake event for the drag so we can pass the time (so to speak).
+    // If we don't do this, then, when the timestamp for the pending button
+    // release event is used for the ungrab, the ungrab can fail due to the
+    // timestamp being _earlier_ than CurrentTime.
+    memset(&fakeEvent, 0, sizeof(GdkEvent));
+    fakeEvent.type = GDK_BUTTON_PRESS;
+    fakeEvent.button.window = gtk_widget_get_window(mHiddenWidget);
+    fakeEvent.button.time = nsWindow::GetLastUserInputTime();
+    fakeEvent.button.device = device;
+  }
+
+  // Put the drag widget in the window group of the source node so that the
+  // gtk_grab_add during gtk_drag_begin is effective.
+  // gtk_window_get_group(nullptr) returns the default window group.
+  GtkWindowGroup* window_group =
+      gtk_window_get_group(GetGtkWindow(mSourceDocument));
+  gtk_window_group_add_window(window_group, GTK_WINDOW(mHiddenWidget));
+
+  // start our drag.
+  GdkDragContext* context = gtk_drag_begin_with_coordinates(
+      mHiddenWidget, sourceList, action, 1,
+      existingEvent ? existingEvent : &fakeEvent, -1, -1);
+
+  if (originGdkWindow) {
+    mSourceWindow = nsWindow::GetWindow(originGdkWindow);
+    if (mSourceWindow) {
+      mSourceWindow->SetDragSource(context);
+    }
+  }
+
+  LOGDRAGSERVICE("  GdkDragContext [%p] nsWindow [%p]", context,
+                 mSourceWindow.get());
+
+  nsresult rv;
+  if (context) {
+    StartDragSession();
+
+    // GTK uses another hidden window for receiving mouse events.
+    sGrabWidget = gtk_window_group_get_current_grab(window_group);
+    if (sGrabWidget) {
+      g_object_ref(sGrabWidget);
+      // Only motion and key events are required but connect to
+      // "event-after" as this is never blocked by other handlers.
+      g_signal_connect(sGrabWidget, "event-after",
+                       G_CALLBACK(OnSourceGrabEventAfter), this);
+    }
+    // We don't have a drag end point yet.
+    mEndDragPoint = LayoutDeviceIntPoint(-1, -1);
+    rv = NS_OK;
+  } else {
+    rv = NS_ERROR_FAILURE;
+  }
+
+  gtk_target_list_unref(sourceList);
+
+  return rv;
+}
+
+bool nsDragService::SetAlphaPixmap(SourceSurface* aSurface,
+                                   GdkDragContext* aContext, int32_t aXOffset,
+                                   int32_t aYOffset,
+                                   const LayoutDeviceIntRect& dragRect) {
+  GdkScreen* screen = gtk_widget_get_screen(mHiddenWidget);
+
+  // Transparent drag icons need, like a lot of transparency-related things,
+  // a compositing X window manager
+  if (!gdk_screen_is_composited(screen)) {
+    return false;
+  }
+
+#ifdef cairo_image_surface_create
+#  error "Looks like we're including Mozilla's cairo instead of system cairo"
+#endif
+
+  // TODO: grab X11 pixmap or image data instead of expensive readback.
+  cairo_surface_t* surf = cairo_image_surface_create(
+      CAIRO_FORMAT_ARGB32, dragRect.width, dragRect.height);
+  if (!surf) return false;
+
+  RefPtr<DrawTarget> dt = gfxPlatform::CreateDrawTargetForData(
+      cairo_image_surface_get_data(surf),
+      nsIntSize(dragRect.width, dragRect.height),
+      cairo_image_surface_get_stride(surf), SurfaceFormat::B8G8R8A8);
+  if (!dt) return false;
+
+  dt->ClearRect(Rect(0, 0, dragRect.width, dragRect.height));
+  dt->DrawSurface(
+      aSurface, Rect(0, 0, dragRect.width, dragRect.height),
+      Rect(0, 0, dragRect.width, dragRect.height), DrawSurfaceOptions(),
+      DrawOptions(DRAG_IMAGE_ALPHA_LEVEL, CompositionOp::OP_SOURCE));
+
+  cairo_surface_mark_dirty(surf);
+  cairo_surface_set_device_offset(surf, -aXOffset, -aYOffset);
+
+  // Ensure that the surface is drawn at the correct scale on HiDPI displays.
+  static auto sCairoSurfaceSetDeviceScalePtr =
+      (void (*)(cairo_surface_t*, double, double))dlsym(
+          RTLD_DEFAULT, "cairo_surface_set_device_scale");
+  if (sCairoSurfaceSetDeviceScalePtr) {
+    gint scale = mozilla::widget::ScreenHelperGTK::GetGTKMonitorScaleFactor();
+    sCairoSurfaceSetDeviceScalePtr(surf, scale, scale);
+  }
+
+  gtk_drag_set_icon_surface(aContext, surf);
+  cairo_surface_destroy(surf);
+  return true;
+}
+
+NS_IMETHODIMP
+nsDragService::StartDragSession() {
+  LOGDRAGSERVICE("nsDragService::StartDragSession");
+  mTempFileUrls.Clear();
+  return nsBaseDragService::StartDragSession();
+}
+
+bool nsDragService::RemoveTempFiles() {
+  LOGDRAGSERVICE("nsDragService::RemoveTempFiles");
+
+  // We can not delete the temporary files immediately after the
+  // drag has finished, because the target application might have not
+  // copied the temporary file yet. The Qt toolkit does not provide a
+  // way to mark a drop as finished in an asynchronous way, so most
+  // Qt based applications do send the dnd_finished signal before they
+  // have actually accessed the data from the temporary file.
+  // (https://bugreports.qt.io/browse/QTBUG-5441)
+  //
+  // To work also with these applications we collect all temporary
+  // files in mTemporaryFiles array and remove them here in the timer event.
+  auto files = std::move(mTemporaryFiles);
+  for (nsIFile* file : files) {
+#ifdef MOZ_LOGGING
+    if (MOZ_LOG_TEST(gWidgetDragLog, LogLevel::Debug)) {
+      nsAutoCString path;
+      if (NS_SUCCEEDED(file->GetNativePath(path))) {
+        LOGDRAGSERVICE("  removing %s", path.get());
+      }
+    }
+#endif
+    file->Remove(/* recursive = */ true);
+  }
+  MOZ_ASSERT(mTemporaryFiles.IsEmpty());
+  mTempFileTimerID = 0;
+  // Return false to remove the timer added by g_timeout_add_full().
+  return false;
+}
+
+gboolean nsDragService::TaskRemoveTempFiles(gpointer data) {
+  RefPtr<nsDragService> dragService = static_cast<nsDragService*>(data);
+  return dragService->RemoveTempFiles();
+}
+
+NS_IMETHODIMP
+nsDragService::EndDragSession(bool aDoneDrag, uint32_t aKeyModifiers) {
+  LOGDRAGSERVICE("nsDragService::EndDragSession(%p) %d",
+                 mTargetDragContext.get(), aDoneDrag);
+
+  if (sGrabWidget) {
+    g_signal_handlers_disconnect_by_func(
+        sGrabWidget, FuncToGpointer(OnSourceGrabEventAfter), this);
+    g_object_unref(sGrabWidget);
+    sGrabWidget = nullptr;
+
+    if (sMotionEventTimerID) {
+      g_source_remove(sMotionEventTimerID);
+      sMotionEventTimerID = 0;
+    }
+    if (sMotionEvent) {
+      TakeMotionEvent();
+    }
+  }
+
+  // unset our drag action
+  SetDragAction(DRAGDROP_ACTION_NONE);
+
+  // start timer to remove temporary files
+  if (mTemporaryFiles.Count() > 0 && !mTempFileTimerID) {
+    LOGDRAGSERVICE("  queue removing of temporary files");
+    // |this| won't be used after nsDragService delete because the timer is
+    // removed in the nsDragService destructor.
+    mTempFileTimerID =
+        g_timeout_add(NS_DND_TMP_CLEANUP_TIMEOUT, TaskRemoveTempFiles, this);
+    mTempFileUrls.Clear();
+  }
+
+  // We're done with the drag context.
+  if (mSourceWindow) {
+    mSourceWindow->SetDragSource(nullptr);
+    mSourceWindow = nullptr;
+  }
+  mTargetDragContextForRemote = nullptr;
+  mTargetWindow = nullptr;
+  mPendingWindow = nullptr;
+  mCachedDragContext = 0;
+
+  return nsBaseDragService::EndDragSession(aDoneDrag, aKeyModifiers);
+}
+
+// nsIDragSession
+NS_IMETHODIMP
+nsDragService::SetCanDrop(bool aCanDrop) {
+  LOGDRAGSERVICE("nsDragService::SetCanDrop %d", aCanDrop);
+  mCanDrop = aCanDrop;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDragService::GetCanDrop(bool* aCanDrop) {
+  LOGDRAGSERVICE("nsDragService::GetCanDrop");
+  *aCanDrop = mCanDrop;
+  return NS_OK;
+}
+
+static void UTF16ToNewUTF8(const char16_t* aUTF16, uint32_t aUTF16Len,
+                           char** aUTF8, uint32_t* aUTF8Len) {
+  nsDependentSubstring utf16(aUTF16, aUTF16Len);
+  *aUTF8 = ToNewUTF8String(utf16, aUTF8Len);
+}
+
+static void UTF8ToNewUTF16(const char* aUTF8, uint32_t aUTF8Len,
+                           char16_t** aUTF16, uint32_t* aUTF16Len) {
+  nsDependentCSubstring utf8(aUTF8, aUTF8Len);
+  *aUTF16 = UTF8ToNewUnicode(utf8, aUTF16Len);
+}
+
+// extract an item from text/uri-list formatted data and convert it to
+// unicode.
+static void GetTextUriListItem(const char* data, uint32_t datalen,
+                               uint32_t aItemIndex, char16_t** convertedText,
+                               uint32_t* convertedTextLen) {
+  const char* p = data;
+  const char* endPtr = p + datalen;
+  unsigned int count = 0;
+
+  *convertedText = nullptr;
+  while (p < endPtr) {
+    // skip whitespace (if any)
+    while (p < endPtr && *p != '\0' && isspace(*p)) p++;
+    // if we aren't at the end of the line, we have a url
+    if (p != endPtr && *p != '\0' && *p != '\n' && *p != '\r') count++;
+    // this is the item we are after ...
+    if (aItemIndex + 1 == count) {
+      const char* q = p;
+      while (q < endPtr && *q != '\0' && *q != '\n' && *q != '\r') q++;
+      UTF8ToNewUTF16(p, q - p, convertedText, convertedTextLen);
+      break;
+    }
+    // skip to the end of the line
+    while (p < endPtr && *p != '\0' && *p != '\n') p++;
+    p++;  // skip the actual newline as well.
+  }
+
+  // didn't find the desired item, so just pass the whole lot
+  if (!*convertedText) {
+    UTF8ToNewUTF16(data, datalen, convertedText, convertedTextLen);
+  }
+}
+
+// Spins event loop, called from JS.
+// Can lead to another round of drag_motion events.
+NS_IMETHODIMP
+nsDragService::GetNumDropItems(uint32_t* aNumItems) {
+  LOGDRAGSERVICE("nsDragService::GetNumDropItems");
+
+  if (!mTargetWidget) {
+    LOGDRAGSERVICE(
+        "*** warning: GetNumDropItems \
+               called without a valid target widget!\n");
+    *aNumItems = 0;
+    return NS_OK;
+  }
+
+  bool isList = IsTargetContextList();
+  if (isList) {
+    if (!mSourceDataItems) {
+      *aNumItems = 0;
+      return NS_OK;
+    }
+    mSourceDataItems->GetLength(aNumItems);
+  } else {
+    // text/uri-list
+    GdkAtom gdkFlavor = gdk_atom_intern(gTextUriListType, FALSE);
+    if (!gdkFlavor) {
+      *aNumItems = 0;
+      return NS_OK;
+    }
+
+    nsTArray<nsCString> dragFlavors;
+    GetDragFlavors(dragFlavors);
+    GetTargetDragData(gdkFlavor, dragFlavors);
+
+    // application/vnd.portal.files
+    if (!mTargetDragUris) {
+      gdkFlavor = gdk_atom_intern(gPortalFile, FALSE);
+      if (!gdkFlavor) {
+        *aNumItems = 0;
+        return NS_OK;
+      }
+      GetTargetDragData(gdkFlavor, dragFlavors);
+    }
+
+    // application/vnd.portal.filetransfer
+    if (!mTargetDragUris) {
+      gdkFlavor = gdk_atom_intern(gPortalFileTransfer, FALSE);
+      if (!gdkFlavor) {
+        *aNumItems = 0;
+        return NS_OK;
+      }
+      GetTargetDragData(gdkFlavor, dragFlavors);
+    }
+
+    if (mTargetDragUris) {
+      *aNumItems = g_strv_length(mTargetDragUris.get());
+    } else
+      *aNumItems = 1;
+  }
+  LOGDRAGSERVICE("  NumOfDropItems %d", *aNumItems);
+  return NS_OK;
+}
+
+void nsDragService::GetDragFlavors(nsTArray<nsCString>& aFlavors) {
+  for (GList* tmp = gdk_drag_context_list_targets(mTargetDragContext); tmp;
+       tmp = tmp->next) {
+    GdkAtom atom = GDK_POINTER_TO_ATOM(tmp->data);
+    GUniquePtr<gchar> name(gdk_atom_name(atom));
+    if (!name) {
+      continue;
+    }
+    aFlavors.AppendElement(nsCString(name.get()));
+  }
+}
+
+static nsresult GetFileFromUri(const nsCString& aUri,
+                               nsCOMPtr<nsIFile>& aFile) {
+  nsresult rv;
+  nsCOMPtr<nsIIOService> ioService = do_GetIOService(&rv);
+  nsCOMPtr<nsIURI> fileURI;
+  rv = ioService->NewURI(aUri, nullptr, nullptr, getter_AddRefs(fileURI));
+  if (NS_SUCCEEDED(rv)) {
+    nsCOMPtr<nsIFileURL> fileURL = do_QueryInterface(fileURI, &rv);
+    if (NS_SUCCEEDED(rv)) {
+      rv = fileURL->GetFile(getter_AddRefs(aFile));
+      if (NS_SUCCEEDED(rv)) {
+        return NS_OK;
+      }
+    }
+  }
+  return rv;
+}
+
+nsresult GetReachableFileFromUriList(char** aFileUriList, uint32_t aItemIndex,
+                                     nsCOMPtr<nsIFile>& aFile) {
+  if (!aFileUriList || !(g_strv_length(aFileUriList) > aItemIndex) ||
+      !aFileUriList[aItemIndex]) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  nsresult rv;
+  rv = GetFileFromUri(nsDependentCString(aFileUriList[aItemIndex]), aFile);
+  if (NS_SUCCEEDED(rv)) {
+    bool fileExists = false;
+    aFile->Exists(&fileExists);
+    if (fileExists) {
+      LOGDRAG("  good, file %s exists\n", aFileUriList[aItemIndex]);
+      return NS_OK;
+    }
+  }
+  LOGDRAG("  uri %s not reachable/not found\n", aFileUriList[aItemIndex]);
+  aFile = nullptr;
+  return NS_ERROR_FILE_NOT_FOUND;
+}
+
+// Spins event loop, called from JS.
+// Can lead to another round of drag_motion events.
+NS_IMETHODIMP
+nsDragService::GetData(nsITransferable* aTransferable, uint32_t aItemIndex) {
+  LOGDRAGSERVICE("nsDragService::GetData(), index %d", aItemIndex);
+
+  // make sure that we have a transferable
+  if (!aTransferable) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  if (!mTargetWidget) {
+    LOGDRAGSERVICE(
+        "*** failed: GetData called without a valid target widget!\n");
+    return NS_ERROR_FAILURE;
+  }
+
+  // get flavor list that includes all acceptable flavors (including
+  // ones obtained through conversion).
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanImport(flavors);
+  if (NS_FAILED(rv)) {
+    LOGDRAGSERVICE("  failed to get flavors, quit.");
+    return rv;
+  }
+
+  // check to see if this is an internal list
+  bool isList = IsTargetContextList();
+
+  if (isList) {
+    LOGDRAGSERVICE("  Process as a list...");
+    // find a matching flavor
+    for (uint32_t i = 0; i < flavors.Length(); ++i) {
+      nsCString& flavorStr = flavors[i];
+      LOGDRAGSERVICE("  [%d] flavor is %s\n", i, flavorStr.get());
+      // get the item with the right index
+      nsCOMPtr<nsITransferable> item =
+          do_QueryElementAt(mSourceDataItems, aItemIndex);
+      if (!item) continue;
+
+      nsCOMPtr<nsISupports> data;
+      LOGDRAGSERVICE("  trying to get transfer data for %s\n", flavorStr.get());
+      rv = item->GetTransferData(flavorStr.get(), getter_AddRefs(data));
+      if (NS_FAILED(rv)) {
+        LOGDRAGSERVICE("  failed.\n");
+        continue;
+      }
+      rv = aTransferable->SetTransferData(flavorStr.get(), data);
+      if (NS_FAILED(rv)) {
+        LOGDRAGSERVICE("  fail to set transfer data into transferable!\n");
+        continue;
+      }
+      LOGDRAGSERVICE("  succeeded\n");
+      // ok, we got the data
+      return NS_OK;
+    }
+    // if we got this far, we failed
+    LOGDRAGSERVICE("  failed to match flavors\n");
+    return NS_ERROR_FAILURE;
+  }
+
+  nsTArray<nsCString> dragFlavors;
+  GetDragFlavors(dragFlavors);
+
+  // Now walk down the list of flavors. When we find one that is
+  // actually present, copy out the data into the transferable in that
+  // format. SetTransferData() implicitly handles conversions.
+  for (uint32_t i = 0; i < flavors.Length(); ++i) {
+    nsCString& flavorStr = flavors[i];
+
+    GdkAtom gdkFlavor;
+    if (flavorStr.EqualsLiteral(kTextMime)) {
+      gdkFlavor = gdk_atom_intern(gTextPlainUTF8Type, FALSE);
+    } else {
+      gdkFlavor = gdk_atom_intern(flavorStr.get(), FALSE);
+    }
+    LOGDRAGSERVICE("  we're getting data %s (gdk flavor %p)\n", flavorStr.get(),
+                   gdkFlavor);
+    bool dataFound = false;
+    nsCOMPtr<nsIFile> file;
+    if (gdkFlavor) {
+      GetTargetDragData(gdkFlavor, dragFlavors);
+      GetReachableFileFromUriList(mTargetDragUris.get(), aItemIndex, file);
+    }
+
+    // application/vnd.portal.files
+    if (!file || !mTargetDragUris) {
+      LOGDRAGSERVICE("  file not found, proceed with %s flavor\n", gPortalFile);
+      gdkFlavor = gdk_atom_intern(gPortalFile, FALSE);
+      if (gdkFlavor) {
+        GetTargetDragData(gdkFlavor, dragFlavors);
+        GetReachableFileFromUriList(mTargetDragUris.get(), aItemIndex, file);
+      }
+    }
+
+    // application/vnd.portal.filetransfer
+    if (!file || !mTargetDragUris) {
+      LOGDRAGSERVICE("  file not found, proceed with %s flavor\n",
+                     gPortalFileTransfer);
+      gdkFlavor = gdk_atom_intern(gPortalFileTransfer, FALSE);
+      if (gdkFlavor) {
+        GetTargetDragData(gdkFlavor, dragFlavors);
+        GetReachableFileFromUriList(mTargetDragUris.get(), aItemIndex, file);
+      }
+    }
+
+    // Conversion from application/x-moz-file to text/uri-list
+    if ((!file || !mTargetDragUris) && (flavorStr.EqualsLiteral(kFileMime))) {
+      LOGDRAGSERVICE(
+          "  file not found, proceed with conversion %s =>  %s flavor\n",
+          kFileMime, gTextUriListType);
+
+      gdkFlavor = gdk_atom_intern(gTextUriListType, FALSE);
+      if (gdkFlavor) {
+        GetTargetDragData(gdkFlavor, dragFlavors);
+        GetReachableFileFromUriList(mTargetDragUris.get(), aItemIndex, file);
+      }
+    }
+
+    if (file) {
+      LOGDRAGSERVICE("  from drag uris set as file %s - flavor: %s",
+                     mTargetDragUris.get()[aItemIndex], flavorStr.get());
+      aTransferable->SetTransferData(flavorStr.get(), file);
+      return NS_OK;
+    }
+
+    if (mTargetDragData) {
+      LOGDRAGSERVICE("  dataFound = true\n");
+      dataFound = true;
+    } else {
+      LOGDRAGSERVICE("  dataFound = false, try conversions\n");
+      // If we are looking for text/plain, try again with non utf-8 text.
+      if (flavorStr.EqualsLiteral(kTextMime)) {
+        LOGDRAGSERVICE("  conversion %s => %s", kTextMime, kTextMime);
+        gdkFlavor = gdk_atom_intern(kTextMime, FALSE);
+        GetTargetDragData(gdkFlavor, dragFlavors);
+        if (mTargetDragData) {
+          dataFound = true;
+        }  // if plain text flavor present
+      }    // if looking for text/plain
+
+      // if we are looking for text/x-moz-url and we failed to find
+      // it on the clipboard, try again with text/uri-list, and then
+      // _NETSCAPE_URL
+      if (flavorStr.EqualsLiteral(kURLMime)) {
+        LOGDRAGSERVICE("  conversion %s => %s", kURLMime, gTextUriListType);
+        gdkFlavor = gdk_atom_intern(gTextUriListType, FALSE);
+        GetTargetDragData(gdkFlavor, dragFlavors);
+        if (mTargetDragData) {
+          const char* data = reinterpret_cast<char*>(mTargetDragData);
+          char16_t* convertedText = nullptr;
+          uint32_t convertedTextLen = 0;
+
+          GetTextUriListItem(data, mTargetDragDataLen, aItemIndex,
+                             &convertedText, &convertedTextLen);
+
+          if (convertedText) {
+            // out with the old, in with the new
+            g_free(mTargetDragData);
+            mTargetDragData = convertedText;
+            mTargetDragDataLen = convertedTextLen * 2;
+            dataFound = true;
+          }
+        }
+        if (!dataFound) {
+          LOGDRAGSERVICE("  conversion %s => %s", kURLMime, gMozUrlType);
+          gdkFlavor = gdk_atom_intern(gMozUrlType, FALSE);
+          GetTargetDragData(gdkFlavor, dragFlavors);
+          if (mTargetDragData) {
+            const char* castedText = reinterpret_cast<char*>(mTargetDragData);
+            char16_t* convertedText = nullptr;
+            uint32_t convertedTextLen = 0;
+            UTF8ToNewUTF16(castedText, mTargetDragDataLen, &convertedText,
+                           &convertedTextLen);
+            if (convertedText) {
+              // out with the old, in with the new
+              g_free(mTargetDragData);
+              mTargetDragData = convertedText;
+              mTargetDragDataLen = convertedTextLen * 2;
+              dataFound = true;
+            }
+          }
+        }
+      }
+
+    }  // else we try one last ditch effort to find our data
+
+    if (dataFound) {
+      LOGDRAGSERVICE("  actual data found %s\n",
+                     GUniquePtr<gchar>(gdk_atom_name(gdkFlavor)).get());
+
+      if (flavorStr.EqualsLiteral(kTextMime)) {
+        // The text is in UTF-8, so convert the text into UTF-16
+        const char* text = static_cast<char*>(mTargetDragData);
+        NS_ConvertUTF8toUTF16 ucs2string(text, mTargetDragDataLen);
+        char16_t* convertedText = ToNewUnicode(ucs2string, mozilla::fallible);
+        if (convertedText) {
+          g_free(mTargetDragData);
+          mTargetDragData = convertedText;
+          mTargetDragDataLen = ucs2string.Length() * 2;
+        }
+      }
+
+      if (flavorStr.EqualsLiteral(kJPEGImageMime) ||
+          flavorStr.EqualsLiteral(kJPGImageMime) ||
+          flavorStr.EqualsLiteral(kPNGImageMime) ||
+          flavorStr.EqualsLiteral(kGIFImageMime)) {
+        LOGDRAGSERVICE("  saving as image %s\n", flavorStr.get());
+
+        nsCOMPtr<nsIInputStream> byteStream;
+        NS_NewByteInputStream(getter_AddRefs(byteStream),
+                              Span((char*)mTargetDragData, mTargetDragDataLen),
+                              NS_ASSIGNMENT_COPY);
+        aTransferable->SetTransferData(flavorStr.get(), byteStream);
+        continue;
+      }
+
+      if (!flavorStr.EqualsLiteral(kCustomTypesMime)) {
+        // the DOM only wants LF, so convert from MacOS line endings
+        // to DOM line endings.
+        nsLinebreakHelpers::ConvertPlatformToDOMLinebreaks(
+            flavorStr.EqualsLiteral(kRTFMime), &mTargetDragData,
+            reinterpret_cast<int*>(&mTargetDragDataLen));
+      }
+
+      // put it into the transferable.
+      nsCOMPtr<nsISupports> genericDataWrapper;
+      nsPrimitiveHelpers::CreatePrimitiveForData(
+          flavorStr, mTargetDragData, mTargetDragDataLen,
+          getter_AddRefs(genericDataWrapper));
+      aTransferable->SetTransferData(flavorStr.get(), genericDataWrapper);
+      // we found one, get out of this loop!
+      break;
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDragService::IsDataFlavorSupported(const char* aDataFlavor, bool* _retval) {
+  LOGDRAGSERVICE("nsDragService::IsDataFlavorSupported(%p) %s",
+                 mTargetDragContext.get(), aDataFlavor);
+  if (!_retval) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  // set this to no by default
+  *_retval = false;
+
+  // check to make sure that we have a drag object set, here
+  if (!mTargetWidget) {
+    LOGDRAGSERVICE(
+        "*** warning: IsDataFlavorSupported called without a valid target "
+        "widget!\n");
+    return NS_OK;
+  }
+
+  // check to see if the target context is a list.
+  bool isList = IsTargetContextList();
+  // if it is, just look in the internal data since we are the source
+  // for it.
+  if (isList) {
+    LOGDRAGSERVICE("  It's a list");
+    uint32_t numDragItems = 0;
+    // if we don't have mDataItems we didn't start this drag so it's
+    // an external client trying to fool us.
+    if (!mSourceDataItems) {
+      LOGDRAGSERVICE("  quit");
+      return NS_OK;
+    }
+    mSourceDataItems->GetLength(&numDragItems);
+    LOGDRAGSERVICE("  drag items %d", numDragItems);
+    for (uint32_t itemIndex = 0; itemIndex < numDragItems; ++itemIndex) {
+      nsCOMPtr<nsITransferable> currItem =
+          do_QueryElementAt(mSourceDataItems, itemIndex);
+      if (currItem) {
+        nsTArray<nsCString> flavors;
+        currItem->FlavorsTransferableCanExport(flavors);
+        for (uint32_t i = 0; i < flavors.Length(); ++i) {
+          LOGDRAGSERVICE("  checking %s against %s\n", flavors[i].get(),
+                         aDataFlavor);
+          if (flavors[i].Equals(aDataFlavor)) {
+            LOGDRAGSERVICE("  found.\n");
+            *_retval = true;
+          }
+        }
+      }
+    }
+    return NS_OK;
+  }
+
+  // check the target context vs. this flavor, one at a time
+  GList* tmp = nullptr;
+  if (mTargetDragContext) {
+    tmp = gdk_drag_context_list_targets(mTargetDragContext);
+  }
+
+  for (; tmp; tmp = tmp->next) {
+    /* Bug 331198 */
+    GdkAtom atom = GDK_POINTER_TO_ATOM(tmp->data);
+    GUniquePtr<gchar> name(gdk_atom_name(atom));
+    if (!name) {
+      continue;
+    }
+
+    if (strcmp(name.get(), aDataFlavor) == 0) {
+      *_retval = true;
+    }
+    // check for automatic text/uri-list -> text/x-moz-url mapping
+    else if (strcmp(name.get(), gTextUriListType) == 0 &&
+             (strcmp(aDataFlavor, kURLMime) == 0 ||
+              strcmp(aDataFlavor, kFileMime) == 0)) {
+      *_retval = true;
+    }
+    // check for automatic _NETSCAPE_URL -> text/x-moz-url mapping
+    else if (strcmp(name.get(), gMozUrlType) == 0 &&
+             (strcmp(aDataFlavor, kURLMime) == 0)) {
+      *_retval = true;
+    }
+    // check for file portal
+    // If we're asked for kURLMime/kFileMime we can convert gPortalFile
+    // or gPortalFileTransfer to it.
+    else if ((strcmp(name.get(), gPortalFile) == 0 ||
+              strcmp(name.get(), gPortalFileTransfer) == 0) &&
+             (strcmp(aDataFlavor, kURLMime) == 0 ||
+              strcmp(aDataFlavor, kFileMime) == 0)) {
+      *_retval = true;
+    }
+    if (*_retval) {
+      LOGDRAGSERVICE("  supported, with converting %s => %s", name.get(),
+                     aDataFlavor);
+    }
+  }
+
+  if (!*_retval) {
+    LOGDRAGSERVICE("  %s is not supported", aDataFlavor);
+  }
+
+  return NS_OK;
+}
+
+void nsDragService::ReplyToDragMotion(GdkDragContext* aDragContext,
+                                      guint aTime) {
+  LOGDRAGSERVICE("nsDragService::ReplyToDragMotion(%p) can drop %d",
+                 aDragContext, mCanDrop);
+
+  GdkDragAction action = (GdkDragAction)0;
+  if (mCanDrop) {
+    // notify the dragger if we can drop
+    switch (mDragAction) {
+      case DRAGDROP_ACTION_COPY:
+        LOGDRAGSERVICE("  set explicit action copy");
+        action = GDK_ACTION_COPY;
+        break;
+      case DRAGDROP_ACTION_LINK:
+        LOGDRAGSERVICE("  set explicit action link");
+        action = GDK_ACTION_LINK;
+        break;
+      case DRAGDROP_ACTION_NONE:
+        LOGDRAGSERVICE("  set explicit action none");
+        action = (GdkDragAction)0;
+        break;
+      default:
+        LOGDRAGSERVICE("  set explicit action move");
+        action = GDK_ACTION_MOVE;
+        break;
+    }
+  } else {
+    LOGDRAGSERVICE("  mCanDrop is false, disable drop");
+  }
+
+  // gdk_drag_status() is a kind of red herring here.
+  // It does not control final D&D operation type (copy/move) but controls
+  // drop/no-drop D&D state and default cursor type (copy/move).
+
+  // Actual D&D operation is determined by mDragAction which is set by
+  // SetDragAction() from UpdateDragAction() or gecko/layout.
+
+  // State passed to gdk_drag_status() sets default D&D cursor type
+  // which can be switched by key control (CTRL/SHIFT).
+  // If user changes D&D cursor (and D&D operation) we're notified by
+  // gdk_drag_context_get_selected_action() and update mDragAction.
+
+  // But if we pass mDragAction back to gdk_drag_status() the D&D operation
+  // becames locked and won't be returned when D&D modifiers (CTRL/SHIFT)
+  // are released.
+
+  // This gdk_drag_context_get_selected_action() -> gdk_drag_status() ->
+  // gdk_drag_context_get_selected_action() cycle happens on Wayland.
+  if (widget::GdkIsWaylandDisplay() && action == GDK_ACTION_COPY) {
+    LOGDRAGSERVICE("  Wayland: switch copy to move");
+    action = GDK_ACTION_MOVE;
+  }
+
+  LOGDRAGSERVICE("  gdk_drag_status() action %d", action);
+  gdk_drag_status(aDragContext, action, aTime);
+}
+
+void nsDragService::EnsureCachedDataValidForContext(
+    GdkDragContext* aDragContext) {
+  if (mCachedDragContext != (uintptr_t)aDragContext) {
+    mCachedUris.Clear();
+    mCachedData.Clear();
+    mCachedDragContext = (uintptr_t)aDragContext;
+  }
+}
+
+void nsDragService::TargetDataReceived(GtkWidget* aWidget,
+                                       GdkDragContext* aContext, gint aX,
+                                       gint aY,
+                                       GtkSelectionData* aSelectionData,
+                                       guint aInfo, guint32 aTime) {
+  LOGDRAGSERVICE("nsDragService::TargetDataReceived(%p)", aContext);
+  TargetResetData();
+
+  EnsureCachedDataValidForContext(aContext);
+
+  mTargetDragDataReceived = true;
+
+  GdkAtom target = gtk_selection_data_get_target(aSelectionData);
+  GUniquePtr<gchar> name(gdk_atom_name(target));
+  nsDependentCString flavor(name.get());
+
+  if (gtk_targets_include_uri(&target, 1)) {
+    GUniquePtr<gchar*> uris(gtk_selection_data_get_uris(aSelectionData));
+#ifdef MOZ_LOGGING
+    if (MOZ_LOG_TEST(gWidgetDragLog, mozilla::LogLevel::Debug)) {
+      gchar** uri = uris.get();
+      while (uri && *uri) {
+        LOGDRAGSERVICE("  got uri %s, MIME %s", *uri, flavor.get());
+        uri++;
+      }
+    }
+#endif
+    uris.swap(mTargetDragUris);
+    if (mTargetDragUris) {
+      mCachedUris.InsertOrUpdate(
+          flavor, GUniquePtr<gchar*>(g_strdupv(mTargetDragUris.get())));
+    } else {
+      LOGDRAGSERVICE("Failed to get uri list\n");
+      mCachedUris.InsertOrUpdate(flavor, GUniquePtr<gchar*>(nullptr));
+    }
+    return;
+  }
+
+  const guchar* data = gtk_selection_data_get_data(aSelectionData);
+  gint len = gtk_selection_data_get_length(aSelectionData);
+  if (len > 0 && data) {
+    mTargetDragDataLen = len;
+    mTargetDragData = g_malloc(mTargetDragDataLen);
+    memcpy(mTargetDragData, data, mTargetDragDataLen);
+
+    LOGDRAGSERVICE("  got data, len = %d", mTargetDragDataLen);
+
+    nsTArray<uint8_t> copy;
+    if (!copy.SetLength(len, fallible)) {
+      return;
+    }
+    memcpy(copy.Elements(), data, len);
+
+    mCachedData.InsertOrUpdate(flavor, std::move(copy));
+  } else {
+    LOGDRAGSERVICE("Failed to get data. selection data len was %d\n",
+                   mTargetDragDataLen);
+    mCachedData.InsertOrUpdate(flavor, nsTArray<uint8_t>());
+  }
+  LOGDRAGSERVICE("  got data, MIME %s", flavor.get());
+}
+
+bool nsDragService::IsTargetContextList(void) {
+  bool retval = false;
+
+  // gMimeListType drags only work for drags within a single process. The
+  // gtk_drag_get_source_widget() function will return nullptr if the source
+  // of the drag is another app, so we use it to check if a gMimeListType
+  // drop will work or not.
+  if (mTargetDragContext &&
+      gtk_drag_get_source_widget(mTargetDragContext) == nullptr) {
+    return retval;
+  }
+
+  GList* tmp = nullptr;
+  if (mTargetDragContext) {
+    tmp = gdk_drag_context_list_targets(mTargetDragContext);
+  }
+
+  // walk the list of context targets and see if one of them is a list
+  // of items.
+  for (; tmp; tmp = tmp->next) {
+    /* Bug 331198 */
+    GdkAtom atom = GDK_POINTER_TO_ATOM(tmp->data);
+    GUniquePtr<gchar> name(gdk_atom_name(atom));
+    if (name && !strcmp(name.get(), gMimeListType)) {
+      return true;
+    }
+  }
+
+  return retval;
+}
+
+// Spins event loop, called from eDragTaskMotion handler by
+// DispatchMotionEvents().
+// Can lead to another round of drag_motion events.
+void nsDragService::GetTargetDragData(GdkAtom aFlavor,
+                                      nsTArray<nsCString>& aDropFlavors) {
+  LOGDRAGSERVICE("nsDragService::GetTargetDragData(%p) '%s'\n",
+                 mTargetDragContext.get(),
+                 GUniquePtr<gchar>(gdk_atom_name(aFlavor)).get());
+
+  // reset our target data areas
+  TargetResetData();
+
+  GUniquePtr<gchar> name(gdk_atom_name(aFlavor));
+  nsDependentCString flavor(name.get());
+
+  // Return early when requested MIME is not offered by D&D.
+  if (!aDropFlavors.Contains(flavor)) {
+    LOGDRAGSERVICE("  %s is missing", flavor.get());
+    return;
+  }
+
+  if (mTargetDragContext) {
+    // We keep a copy of the requested data with the same life-time
+    // as mTargetDragContext.
+    // Especially with multiple items the same data is requested
+    // very often.
+    EnsureCachedDataValidForContext(mTargetDragContext);
+    if (auto cached = mCachedUris.Lookup(flavor)) {
+      LOGDRAGSERVICE("  using cached uri list for %s", flavor.get());
+
+      mTargetDragUris = GUniquePtr<gchar*>(g_strdupv(cached->get()));
+      mTargetDragDataReceived = true;
+      LOGDRAGSERVICE("  %s found in cache", flavor.get());
+      return;
+    }
+    if (auto cached = mCachedData.Lookup(flavor)) {
+      mTargetDragDataLen = cached->Length();
+      LOGDRAGSERVICE("  using cached data for %s, length is %d", flavor.get(),
+                     mTargetDragDataLen);
+
+      if (mTargetDragDataLen) {
+        mTargetDragData = g_malloc(mTargetDragDataLen);
+        memcpy(mTargetDragData, cached->Elements(), mTargetDragDataLen);
+      }
+
+      mTargetDragDataReceived = true;
+      LOGDRAGSERVICE("  %s found in cache", flavor.get());
+      return;
+    }
+
+    gtk_drag_get_data(mTargetWidget, mTargetDragContext, aFlavor, mTargetTime);
+
+    LOGDRAGSERVICE("  about to start inner iteration.");
+    gtk_main_iteration();
+
+    PRTime entryTime = PR_Now();
+    while (!mTargetDragDataReceived && mDoingDrag) {
+      // check the number of iterations
+      LOGDRAGSERVICE("  doing iteration...\n");
+      PR_Sleep(PR_MillisecondsToInterval(10)); /* sleep for 10 ms/iteration */
+      if (PR_Now() - entryTime > NS_DND_TIMEOUT) {
+        LOGDRAGSERVICE("  failed to get D&D data in time!\n");
+        break;
+      }
+      gtk_main_iteration();
+    }
+  }
+
+#ifdef MOZ_LOGGING
+  if (mTargetDragUris || (mTargetDragDataLen && mTargetDragData)) {
+    LOGDRAGSERVICE("  %s got from system", flavor.get());
+  } else {
+    LOGDRAGSERVICE("  %s failed to get from system", flavor.get());
+  }
+#endif
+}
+
+void nsDragService::TargetResetData(void) {
+  mTargetDragDataReceived = false;
+  // make sure to free old data if we have to
+  mTargetDragUris = nullptr;
+  g_free(mTargetDragData);
+  mTargetDragData = 0;
+  mTargetDragDataLen = 0;
+}
+
+static void TargetArrayAddTarget(nsTArray<GtkTargetEntry*>& aTargetArray,
+                                 const char* aTarget) {
+  GtkTargetEntry* target = (GtkTargetEntry*)g_malloc(sizeof(GtkTargetEntry));
+  target->target = g_strdup(aTarget);
+  target->flags = 0;
+  aTargetArray.AppendElement(target);
+  LOGDRAGSERVICESTATIC("adding target %s\n", aTarget);
+}
+
+static bool CanExportAsURLTarget(const char16_t* aURLData, uint32_t aURLLen) {
+  for (const nsLiteralString& disallowed : kDisallowedExportedSchemes) {
+    auto len = disallowed.AsString().Length();
+    if (len < aURLLen) {
+      if (!memcmp(disallowed.get(), aURLData,
+                  /* len is char16_t char count */ len * 2)) {
+        LOGDRAGSERVICESTATIC("rejected URL scheme %s\n",
+                             NS_ConvertUTF16toUTF8(disallowed).get());
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
+GtkTargetList* nsDragService::GetSourceList(void) {
+  if (!mSourceDataItems) {
+    return nullptr;
+  }
+
+  nsTArray<GtkTargetEntry*> targetArray;
+  GtkTargetEntry* targets;
+  GtkTargetList* targetList = 0;
+  uint32_t targetCount = 0;
+  unsigned int numDragItems = 0;
+
+  mSourceDataItems->GetLength(&numDragItems);
+  LOGDRAGSERVICE("  numDragItems = %d", numDragItems);
+
+  // Check to see if we're dragging > 1 item.
+  if (numDragItems > 1) {
+    // as the Xdnd protocol only supports a single item (or is it just
+    // gtk's implementation?), we don't advertise all flavours listed
+    // in the nsITransferable.
+
+    // the application/x-moz-internal-item-list format, which preserves
+    // all information for drags within the same mozilla instance.
+    TargetArrayAddTarget(targetArray, gMimeListType);
+
+    // check what flavours are supported so we can decide what other
+    // targets to advertise.
+    nsCOMPtr<nsITransferable> currItem = do_QueryElementAt(mSourceDataItems, 0);
+
+    if (currItem) {
+      nsTArray<nsCString> flavors;
+      currItem->FlavorsTransferableCanExport(flavors);
+      for (uint32_t i = 0; i < flavors.Length(); ++i) {
+        // check if text/x-moz-url is supported.
+        // If so, advertise
+        // text/uri-list.
+        if (flavors[i].EqualsLiteral(kURLMime)) {
+          TargetArrayAddTarget(targetArray, gTextUriListType);
+          break;
+        }
+      }
+    }  // if item is a transferable
+  } else if (numDragItems == 1) {
+    nsCOMPtr<nsITransferable> currItem = do_QueryElementAt(mSourceDataItems, 0);
+    if (currItem) {
+      nsTArray<nsCString> flavors;
+      currItem->FlavorsTransferableCanExport(flavors);
+      for (uint32_t i = 0; i < flavors.Length(); ++i) {
+        nsCString& flavorStr = flavors[i];
+
+        TargetArrayAddTarget(targetArray, flavorStr.get());
+
+        // If there is a file, add the text/uri-list type.
+        if (flavorStr.EqualsLiteral(kFileMime)) {
+          TargetArrayAddTarget(targetArray, gTextUriListType);
+        }
+        // Check to see if this is text/plain.
+        else if (flavorStr.EqualsLiteral(kTextMime)) {
+          TargetArrayAddTarget(targetArray, gTextPlainUTF8Type);
+        }
+        // Check to see if this is the x-moz-url type.
+        // If it is, add _NETSCAPE_URL
+        // this is a type used by everybody.
+        else if (flavorStr.EqualsLiteral(kURLMime)) {
+          nsCOMPtr<nsISupports> data;
+          if (NS_SUCCEEDED(currItem->GetTransferData(flavorStr.get(),
+                                                     getter_AddRefs(data)))) {
+            void* tmpData = nullptr;
+            uint32_t tmpDataLen = 0;
+            nsPrimitiveHelpers::CreateDataFromPrimitive(
+                nsDependentCString(flavorStr.get()), data, &tmpData,
+                &tmpDataLen);
+            if (tmpData) {
+              if (CanExportAsURLTarget(reinterpret_cast<char16_t*>(tmpData),
+                                       tmpDataLen / 2)) {
+                TargetArrayAddTarget(targetArray, gMozUrlType);
+              }
+              free(tmpData);
+            }
+          }
+        }
+        // check if application/x-moz-file-promise url is supported.
+        // If so, advertise text/uri-list.
+        else if (flavorStr.EqualsLiteral(kFilePromiseURLMime)) {
+          TargetArrayAddTarget(targetArray, gTextUriListType);
+        }
+        // XdndDirectSave, use on X.org only.
+        else if (widget::GdkIsX11Display() && !widget::IsXWaylandProtocol() &&
+                 flavorStr.EqualsLiteral(kFilePromiseMime)) {
+          TargetArrayAddTarget(targetArray, gXdndDirectSaveType);
+        }
+        // kNativeImageMime
+        else if (flavorStr.EqualsLiteral(kNativeImageMime)) {
+          TargetArrayAddTarget(targetArray, kPNGImageMime);
+          TargetArrayAddTarget(targetArray, kJPEGImageMime);
+          TargetArrayAddTarget(targetArray, kJPGImageMime);
+          TargetArrayAddTarget(targetArray, kGIFImageMime);
+        }
+      }
+    }
+  }
+
+  // get all the elements that we created.
+  targetCount = targetArray.Length();
+  if (targetCount) {
+    // allocate space to create the list of valid targets
+    targets = (GtkTargetEntry*)g_malloc(sizeof(GtkTargetEntry) * targetCount);
+    uint32_t targetIndex;
+    for (targetIndex = 0; targetIndex < targetCount; ++targetIndex) {
+      GtkTargetEntry* disEntry = targetArray.ElementAt(targetIndex);
+      // this is a string reference but it will be freed later.
+      targets[targetIndex].target = disEntry->target;
+      targets[targetIndex].flags = disEntry->flags;
+      targets[targetIndex].info = 0;
+    }
+    targetList = gtk_target_list_new(targets, targetCount);
+    // clean up the target list
+    for (uint32_t cleanIndex = 0; cleanIndex < targetCount; ++cleanIndex) {
+      GtkTargetEntry* thisTarget = targetArray.ElementAt(cleanIndex);
+      g_free(thisTarget->target);
+      g_free(thisTarget);
+    }
+    g_free(targets);
+  } else {
+    // We need to create a dummy target list to be able initialize dnd.
+    targetList = gtk_target_list_new(nullptr, 0);
+  }
+  return targetList;
+}
+
+void nsDragService::SourceEndDragSession(GdkDragContext* aContext,
+                                         gint aResult) {
+  LOGDRAGSERVICE("SourceEndDragSession(%p) result %s\n", aContext,
+                 kGtkDragResults[aResult]);
+
+  // this just releases the list of data items that we provide
+  mSourceDataItems = nullptr;
+
+  // Remove this property, if it exists, to satisfy the Direct Save Protocol.
+  GdkAtom property = gdk_atom_intern(gXdndDirectSaveType, FALSE);
+  gdk_property_delete(gdk_drag_context_get_source_window(aContext), property);
+
+  if (!mDoingDrag || mScheduledTask == eDragTaskSourceEnd)
+    // EndDragSession() was already called on drop
+    // or SourceEndDragSession on drag-failed
+    return;
+
+  if (mEndDragPoint.x < 0) {
+    // We don't have a drag end point, so guess
+    gint x, y;
+    GdkDisplay* display = gdk_display_get_default();
+    GdkScreen* screen = gdk_display_get_default_screen(display);
+    GtkWindow* window = GetGtkWindow(mSourceDocument);
+    GdkWindow* gdkWindow = window ? gtk_widget_get_window(GTK_WIDGET(window))
+                                  : gdk_screen_get_root_window(screen);
+    if (!gdkWindow) {
+      return;
+    }
+    gdk_window_get_device_position(
+        gdkWindow, gdk_drag_context_get_device(aContext), &x, &y, nullptr);
+    gint scale = gdk_window_get_scale_factor(gdkWindow);
+    SetDragEndPoint(LayoutDeviceIntPoint(x * scale, y * scale));
+    LOGDRAGSERVICE("  guess drag end point %d %d\n", x * scale, y * scale);
+  }
+
+  // Either the drag was aborted or the drop occurred outside the app.
+  // The dropEffect of mDataTransfer is not updated for motion outside the
+  // app, but is needed for the dragend event, so set it now.
+
+  uint32_t dropEffect;
+
+  if (aResult == GTK_DRAG_RESULT_SUCCESS) {
+    LOGDRAGSERVICE("  drop is accepted");
+    // With GTK+ versions 2.10.x and prior the drag may have been
+    // cancelled (but no drag-failed signal would have been sent).
+    // aContext->dest_window will be non-nullptr only if the drop was
+    // sent.
+    GdkDragAction action = gdk_drag_context_get_dest_window(aContext)
+                               ? gdk_drag_context_get_actions(aContext)
+                               : (GdkDragAction)0;
+
+    // Only one bit of action should be set, but, just in case someone
+    // does something funny, erring away from MOVE, and not recording
+    // unusual action combinations as NONE.
+    if (!action) {
+      LOGDRAGSERVICE("  drop action is none");
+      dropEffect = DRAGDROP_ACTION_NONE;
+    } else if (action & GDK_ACTION_COPY) {
+      LOGDRAGSERVICE("  drop action is copy");
+      dropEffect = DRAGDROP_ACTION_COPY;
+    } else if (action & GDK_ACTION_LINK) {
+      LOGDRAGSERVICE("  drop action is link");
+      dropEffect = DRAGDROP_ACTION_LINK;
+    } else if (action & GDK_ACTION_MOVE) {
+      LOGDRAGSERVICE("  drop action is move");
+      dropEffect = DRAGDROP_ACTION_MOVE;
+    } else {
+      LOGDRAGSERVICE("  drop action is copy");
+      dropEffect = DRAGDROP_ACTION_COPY;
+    }
+  } else {
+    LOGDRAGSERVICE("  drop action is none");
+    dropEffect = DRAGDROP_ACTION_NONE;
+    if (aResult != GTK_DRAG_RESULT_NO_TARGET) {
+      LOGDRAGSERVICE("  drop is user chancelled\n");
+      mUserCancelled = true;
+    }
+  }
+
+  if (mDataTransfer) {
+    mDataTransfer->SetDropEffectInt(dropEffect);
+  }
+
+  // Schedule the appropriate drag end dom events.
+  Schedule(eDragTaskSourceEnd, nullptr, nullptr, LayoutDeviceIntPoint(), 0);
+}
+
+static nsresult GetDownloadDetails(nsITransferable* aTransferable,
+                                   nsIURI** aSourceURI, nsAString& aFilename) {
+  *aSourceURI = nullptr;
+  MOZ_ASSERT(aTransferable != nullptr, "aTransferable must not be null");
+
+  // get the URI from the kFilePromiseURLMime flavor
+  nsCOMPtr<nsISupports> urlPrimitive;
+  nsresult rv = aTransferable->GetTransferData(kFilePromiseURLMime,
+                                               getter_AddRefs(urlPrimitive));
+  if (NS_FAILED(rv)) {
+    return NS_ERROR_FAILURE;
+  }
+  nsCOMPtr<nsISupportsString> srcUrlPrimitive = do_QueryInterface(urlPrimitive);
+  if (!srcUrlPrimitive) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsAutoString srcUri;
+  srcUrlPrimitive->GetData(srcUri);
+  if (srcUri.IsEmpty()) {
+    return NS_ERROR_FAILURE;
+  }
+  nsCOMPtr<nsIURI> sourceURI;
+  NS_NewURI(getter_AddRefs(sourceURI), srcUri);
+
+  nsAutoString srcFileName;
+  nsCOMPtr<nsISupports> fileNamePrimitive;
+  rv = aTransferable->GetTransferData(kFilePromiseDestFilename,
+                                      getter_AddRefs(fileNamePrimitive));
+  if (NS_FAILED(rv)) {
+    return NS_ERROR_FAILURE;
+  }
+  nsCOMPtr<nsISupportsString> srcFileNamePrimitive =
+      do_QueryInterface(fileNamePrimitive);
+  if (srcFileNamePrimitive) {
+    srcFileNamePrimitive->GetData(srcFileName);
+  } else {
+    nsCOMPtr<nsIURL> sourceURL = do_QueryInterface(sourceURI);
+    if (!sourceURL) {
+      return NS_ERROR_FAILURE;
+    }
+    nsAutoCString urlFileName;
+    sourceURL->GetFileName(urlFileName);
+    NS_UnescapeURL(urlFileName);
+    CopyUTF8toUTF16(urlFileName, srcFileName);
+  }
+  if (srcFileName.IsEmpty()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  sourceURI.swap(*aSourceURI);
+  aFilename = srcFileName;
+  return NS_OK;
+}
+
+// See nsContentAreaDragDropDataProvider::GetFlavorData() for reference.
+nsresult nsDragService::CreateTempFile(nsITransferable* aItem,
+                                       nsACString& aURI) {
+  LOGDRAGSERVICE("nsDragService::CreateTempFile()");
+
+  nsCOMPtr<nsIFile> tmpDir;
+  nsresult rv = NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(tmpDir));
+  if (NS_FAILED(rv)) {
+    LOGDRAGSERVICE("  Failed to get temp directory\n");
+    return rv;
+  }
+
+  nsCOMPtr<nsIInputStream> inputStream;
+  nsCOMPtr<nsIChannel> channel;
+
+  // extract the file name and source uri of the promise-file data
+  nsAutoString wideFileName;
+  nsCOMPtr<nsIURI> sourceURI;
+  rv = GetDownloadDetails(aItem, getter_AddRefs(sourceURI), wideFileName);
+  if (NS_FAILED(rv)) {
+    LOGDRAGSERVICE(
+        "  Failed to extract file name and source uri from download url");
+    return rv;
+  }
+
+  // Check if the file is already stored at /tmp.
+  // It happens when drop destination is changed and SourceDataGet() is caled
+  // more than once.
+  nsAutoCString fileName;
+  CopyUTF16toUTF8(wideFileName, fileName);
+  auto fileLen = fileName.Length();
+  for (const auto& url : mTempFileUrls) {
+    auto URLLen = url.Length();
+    if (URLLen > fileLen &&
+        fileName.Equals(nsDependentCString(url, URLLen - fileLen))) {
+      aURI = url;
+      LOGDRAGSERVICE("  recycle file %s", PromiseFlatCString(aURI).get());
+      return NS_OK;
+    }
+  }
+
+  // create and open channel for source uri
+  nsCOMPtr<nsIPrincipal> principal = aItem->GetRequestingPrincipal();
+  nsContentPolicyType contentPolicyType = aItem->GetContentPolicyType();
+  nsCOMPtr<nsICookieJarSettings> cookieJarSettings =
+      aItem->GetCookieJarSettings();
+  rv = NS_NewChannel(getter_AddRefs(channel), sourceURI, principal,
+                     nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
+                     contentPolicyType, cookieJarSettings);
+  if (NS_FAILED(rv)) {
+    LOGDRAGSERVICE("  Failed to create new channel for source uri");
+    return rv;
+  }
+
+  rv = channel->Open(getter_AddRefs(inputStream));
+  if (NS_FAILED(rv)) {
+    LOGDRAGSERVICE("  Failed to open channel for source uri");
+    return rv;
+  }
+
+  // build the file:///tmp/dnd_file URL
+  tmpDir->Append(NS_LITERAL_STRING_FROM_CSTRING("dnd_file"));
+  rv = tmpDir->CreateUnique(nsIFile::DIRECTORY_TYPE, 0700);
+  if (NS_FAILED(rv)) {
+    LOGDRAGSERVICE("  Failed create tmp dir");
+    return rv;
+  }
+
+  // store a copy of that temporary directory so we can
+  // clean them up when nsDragService is destructed
+  nsCOMPtr<nsIFile> tempFile;
+  tmpDir->Clone(getter_AddRefs(tempFile));
+  mTemporaryFiles.AppendObject(tempFile);
+  if (mTempFileTimerID) {
+    g_source_remove(mTempFileTimerID);
+    mTempFileTimerID = 0;
+  }
+
+  // extend file:///tmp/dnd_file/<filename> URL
+  tmpDir->Append(wideFileName);
+
+  nsCOMPtr<nsIOutputStream> outputStream;
+  rv = NS_NewLocalFileOutputStream(getter_AddRefs(outputStream), tmpDir);
+  if (NS_FAILED(rv)) {
+    LOGDRAGSERVICE("  Failed to open output stream for temporary file");
+    return rv;
+  }
+
+  char buffer[8192];
+  uint32_t readCount = 0;
+  uint32_t writeCount = 0;
+  while (1) {
+    rv = inputStream->Read(buffer, sizeof(buffer), &readCount);
+    if (NS_FAILED(rv)) {
+      LOGDRAGSERVICE("  Failed to read data from source uri");
+      return rv;
+    }
+
+    if (readCount == 0) break;
+
+    rv = outputStream->Write(buffer, readCount, &writeCount);
+    if (NS_FAILED(rv)) {
+      LOGDRAGSERVICE("  Failed to write data to temporary file");
+      return rv;
+    }
+  }
+
+  inputStream->Close();
+  rv = outputStream->Close();
+  if (NS_FAILED(rv)) {
+    LOGDRAGSERVICE("  Failed to write data to temporary file");
+    return rv;
+  }
+
+  nsCOMPtr<nsIURI> uri;
+  rv = NS_NewFileURI(getter_AddRefs(uri), tmpDir);
+  if (NS_FAILED(rv)) {
+    LOGDRAGSERVICE("  Failed to get file URI");
+    return rv;
+  }
+  nsCOMPtr<nsIURL> fileURL(do_QueryInterface(uri));
+  if (!fileURL) {
+    LOGDRAGSERVICE("  Failed to query file interface");
+    return NS_ERROR_FAILURE;
+  }
+  rv = fileURL->GetSpec(aURI);
+  if (NS_FAILED(rv)) {
+    LOGDRAGSERVICE("  Failed to get filepath");
+    return rv;
+  }
+
+  // store url of temporary file
+  mTempFileUrls.AppendElement()->Assign(aURI);
+  LOGDRAGSERVICE("  storing tmp file as %s", PromiseFlatCString(aURI).get());
+  return NS_OK;
+}
+
+bool nsDragService::SourceDataAppendURLFileItem(nsACString& aURI,
+                                                nsITransferable* aItem) {
+  // If there is a file available, create a URI from the file.
+  nsCOMPtr<nsISupports> data;
+  nsresult rv = aItem->GetTransferData(kFileMime, getter_AddRefs(data));
+  NS_ENSURE_SUCCESS(rv, false);
+  if (nsCOMPtr<nsIFile> file = do_QueryInterface(data)) {
+    nsCOMPtr<nsIURI> fileURI;
+    NS_NewFileURI(getter_AddRefs(fileURI), file);
+    if (fileURI) {
+      fileURI->GetSpec(aURI);
+      return true;
+    }
+  }
+  return false;
+}
+
+bool nsDragService::SourceDataAppendURLItem(nsITransferable* aItem,
+                                            bool aExternalDrop,
+                                            nsACString& aURI) {
+  nsCOMPtr<nsISupports> data;
+  nsresult rv = aItem->GetTransferData(kURLMime, getter_AddRefs(data));
+  if (NS_FAILED(rv)) {
+    return SourceDataAppendURLFileItem(aURI, aItem);
+  }
+
+  nsCOMPtr<nsISupportsString> string = do_QueryInterface(data);
+  if (!string) {
+    return false;
+  }
+
+  nsAutoString text;
+  string->GetData(text);
+  if (!aExternalDrop || CanExportAsURLTarget(text.get(), text.Length())) {
+    AppendUTF16toUTF8(text, aURI);
+    return true;
+  }
+
+  // We're dropping to another application and the URL can't be exported
+  // as it's internal one (mailbox:// etc.)
+  // Try to get file target directly.
+  if (SourceDataAppendURLFileItem(aURI, aItem)) {
+    return true;
+  }
+
+  // We can't get the file directly so try to download it and save to tmp.
+  // The desktop or file manager expects for drags of promise-file data
+  // the text/uri-list flavor set to a temporary file that contains the
+  // promise-file data.
+  // We open a stream on the <protocol>:// url here and save the content
+  // to file:///tmp/dnd_file/<filename> and pass this url
+  // as text/uri-list flavor.
+
+  // check whether transferable contains FilePromiseUrl flavor...
+  nsCOMPtr<nsISupports> promiseData;
+  rv = aItem->GetTransferData(kFilePromiseURLMime, getter_AddRefs(promiseData));
+  NS_ENSURE_SUCCESS(rv, false);
+
+  // ... if so, create a temporary file and pass its url
+  return NS_SUCCEEDED(CreateTempFile(aItem, aURI));
+}
+
+void nsDragService::SourceDataGetUriList(GdkDragContext* aContext,
+                                         GtkSelectionData* aSelectionData,
+                                         uint32_t aDragItems) {
+  // Check if we're transfering data to another application.
+  // gdk_drag_context_get_dest_window() on X11 returns GdkWindow even for
+  // different application so use nsWindow::GetWindow() to check if that's
+  // our window.
+  const bool isExternalDrop =
+      widget::GdkIsX11Display()
+          ? !nsWindow::GetWindow(gdk_drag_context_get_dest_window(aContext))
+          : !gdk_drag_context_get_dest_window(aContext);
+
+  LOGDRAGSERVICE("nsDragService::SourceDataGetUriLists() len %d external %d",
+                 aDragItems, isExternalDrop);
+
+  // Disable processing of native events until we store all files to /tmp.
+  // Otherwise user can quit drop before we have all files saved
+  // and that cancels whole D&D.
+  AutoSuspendNativeEvents suspend;
+
+  nsAutoCString uriList;
+  for (uint32_t i = 0; i < aDragItems; i++) {
+    nsCOMPtr<nsITransferable> item = do_QueryElementAt(mSourceDataItems, i);
+    if (!item) {
+      continue;
+    }
+    nsAutoCString uri;
+    if (!SourceDataAppendURLItem(item, isExternalDrop, uri)) {
+      continue;
+    }
+    // text/x-moz-url is of form url + "\n" + title.
+    // We just want the url.
+    int32_t separatorPos = uri.FindChar(u'\n');
+    if (separatorPos >= 0) {
+      uri.Truncate(separatorPos);
+    }
+    uriList.Append(uri);
+    uriList.AppendLiteral("\r\n");
+  }
+
+  LOGDRAGSERVICE("URI list\n%s", uriList.get());
+  GdkAtom target = gtk_selection_data_get_target(aSelectionData);
+  gtk_selection_data_set(aSelectionData, target, 8, (guchar*)uriList.get(),
+                         uriList.Length());
+}
+
+void nsDragService::SourceDataGetImage(nsITransferable* aItem,
+                                       GtkSelectionData* aSelectionData) {
+  LOGDRAGSERVICE("nsDragService::SourceDataGetImage()");
+
+  nsresult rv;
+  nsCOMPtr<nsISupports> data;
+  rv = aItem->GetTransferData(kNativeImageMime, getter_AddRefs(data));
+  NS_ENSURE_SUCCESS_VOID(rv);
+
+  LOGDRAGSERVICE("  posting image\n");
+  nsCOMPtr<imgIContainer> image = do_QueryInterface(data);
+  if (!image) {
+    LOGDRAGSERVICE("  do_QueryInterface failed\n");
+    return;
+  }
+  RefPtr<GdkPixbuf> pixbuf = nsImageToPixbuf::ImageToPixbuf(image);
+  if (!pixbuf) {
+    LOGDRAGSERVICE("  ImageToPixbuf failed\n");
+    return;
+  }
+  gtk_selection_data_set_pixbuf(aSelectionData, pixbuf);
+  LOGDRAGSERVICE("  image data set\n");
+  return;
+}
+
+void nsDragService::SourceDataGetXDND(nsITransferable* aItem,
+                                      GdkDragContext* aContext,
+                                      GtkSelectionData* aSelectionData) {
+  LOGDRAGSERVICE("nsDragService::SourceDataGetXDND");
+
+  // Indicate failure by default.
+  GdkAtom target = gtk_selection_data_get_target(aSelectionData);
+  gtk_selection_data_set(aSelectionData, target, 8, (guchar*)"E", 1);
+
+  GdkAtom property = gdk_atom_intern(gXdndDirectSaveType, FALSE);
+  GdkAtom type = gdk_atom_intern(kTextMime, FALSE);
+
+  GdkWindow* srcWindow = gdk_drag_context_get_source_window(aContext);
+  if (!srcWindow) {
+    LOGDRAGSERVICE("  failed to get source GdkWindow!");
+    return;
+  }
+
+  // Ensure null termination.
+  nsAutoCString data;
+  {
+    GUniquePtr<guchar> gdata;
+    gint length = 0;
+    if (!gdk_property_get(srcWindow, property, type, 0, INT32_MAX, FALSE,
+                          nullptr, nullptr, &length, getter_Transfers(gdata))) {
+      LOGDRAGSERVICE("  failed to get gXdndDirectSaveType GdkWindow property.");
+      return;
+    }
+    data.Assign(nsDependentCSubstring((const char*)gdata.get(), length));
+  }
+
+  GUniquePtr<char> hostname;
+  GUniquePtr<char> fullpath(
+      g_filename_from_uri(data.get(), getter_Transfers(hostname), nullptr));
+  if (!fullpath) {
+    LOGDRAGSERVICE("  failed to get file from uri.");
+    return;
+  }
+
+  // If there is no hostname in the URI, NULL will be stored.
+  // We should not accept uris with from a different host.
+  if (hostname) {
+    nsCOMPtr<nsIPropertyBag2> infoService =
+        do_GetService(NS_SYSTEMINFO_CONTRACTID);
+    if (!infoService) {
+      return;
+    }
+    nsAutoCString host;
+    if (NS_SUCCEEDED(infoService->GetPropertyAsACString(u"host"_ns, host))) {
+      if (!host.Equals(hostname.get())) {
+        LOGDRAGSERVICE("  ignored drag because of different host.");
+        // Special error code "F" for this case.
+        gtk_selection_data_set(aSelectionData, target, 8, (guchar*)"F", 1);
+        return;
+      }
+    }
+  }
+
+  LOGDRAGSERVICE("  XdndDirectSave filepath is %s", fullpath.get());
+
+  nsCOMPtr<nsIFile> file;
+  if (NS_FAILED(NS_NewNativeLocalFile(nsDependentCString(fullpath.get()), false,
+                                      getter_AddRefs(file)))) {
+    LOGDRAGSERVICE("  failed to get local file");
+    return;
+  }
+
+  // We have to split the path into a directory and filename,
+  // because our internal file-promise API is based on these.
+  nsCOMPtr<nsIFile> directory;
+  file->GetParent(getter_AddRefs(directory));
+
+  aItem->SetTransferData(kFilePromiseDirectoryMime, directory);
+
+  nsCOMPtr<nsISupportsString> filenamePrimitive =
+      do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID);
+  if (!filenamePrimitive) {
+    return;
+  }
+
+  nsAutoString leafName;
+  file->GetLeafName(leafName);
+  filenamePrimitive->SetData(leafName);
+
+  aItem->SetTransferData(kFilePromiseDestFilename, filenamePrimitive);
+
+  nsCOMPtr<nsISupports> promiseData;
+  nsresult rv =
+      aItem->GetTransferData(kFilePromiseMime, getter_AddRefs(promiseData));
+  NS_ENSURE_SUCCESS_VOID(rv);
+
+  // Indicate success.
+  gtk_selection_data_set(aSelectionData, target, 8, (guchar*)"S", 1);
+  return;
+}
+
+bool nsDragService::SourceDataGetText(nsITransferable* aItem,
+                                      const nsACString& aMIMEType,
+                                      bool aNeedToDoConversionToPlainText,
+                                      GtkSelectionData* aSelectionData) {
+  LOGDRAGSERVICE("nsDragService::SourceDataGetPlain()");
+
+  nsresult rv;
+  nsCOMPtr<nsISupports> data;
+  rv = aItem->GetTransferData(PromiseFlatCString(aMIMEType).get(),
+                              getter_AddRefs(data));
+  NS_ENSURE_SUCCESS(rv, false);
+
+  void* tmpData = nullptr;
+  uint32_t tmpDataLen = 0;
+
+  nsPrimitiveHelpers::CreateDataFromPrimitive(aMIMEType, data, &tmpData,
+                                              &tmpDataLen);
+  // if required, do the extra work to convert unicode to plain
+  // text and replace the output values with the plain text.
+  if (aNeedToDoConversionToPlainText) {
+    char* plainTextData = nullptr;
+    char16_t* castedUnicode = reinterpret_cast<char16_t*>(tmpData);
+    uint32_t plainTextLen = 0;
+    UTF16ToNewUTF8(castedUnicode, tmpDataLen / 2, &plainTextData,
+                   &plainTextLen);
+    if (tmpData) {
+      // this was not allocated using glib
+      free(tmpData);
+      tmpData = plainTextData;
+      tmpDataLen = plainTextLen;
+    }
+  }
+  if (tmpData) {
+    // this copies the data
+    GdkAtom target = gtk_selection_data_get_target(aSelectionData);
+    gtk_selection_data_set(aSelectionData, target, 8, (guchar*)tmpData,
+                           tmpDataLen);
+    // this wasn't allocated with glib
+    free(tmpData);
+  }
+
+  return true;
+}
+
+// We're asked to get data from mSourceDataItems and pass it to
+// GtkSelectionData (Gtk D&D interface).
+// We need to check mSourceDataItems data type and try to convert it
+// to data type accepted by Gtk.
+void nsDragService::SourceDataGet(GtkWidget* aWidget, GdkDragContext* aContext,
+                                  GtkSelectionData* aSelectionData,
+                                  guint32 aTime) {
+  LOGDRAGSERVICE("nsDragService::SourceDataGet(%p)", aContext);
+
+  GdkAtom target = gtk_selection_data_get_target(aSelectionData);
+  GUniquePtr<gchar> requestedTypeName(gdk_atom_name(target));
+  if (!requestedTypeName) {
+    LOGDRAGSERVICE("  failed to get atom name.\n");
+    return;
+  }
+
+  LOGDRAGSERVICE("  Gtk asks us for %s data type\n", requestedTypeName.get());
+  // check to make sure that we have data items to return.
+  if (!mSourceDataItems) {
+    LOGDRAGSERVICE("  Failed to get our data items\n");
+    return;
+  }
+
+  uint32_t dragItems;
+  mSourceDataItems->GetLength(&dragItems);
+  LOGDRAGSERVICE("  source data items %d", dragItems);
+
+  nsDependentCString mimeFlavor(requestedTypeName.get());
+  if (mimeFlavor.EqualsLiteral(gTextUriListType)) {
+    SourceDataGetUriList(aContext, aSelectionData, dragItems);
+    return;
+  }
+
+#ifdef MOZ_LOGGING
+  if (dragItems > 1) {
+    LOGDRAGSERVICE(
+        "  There are %d data items but we're asked for %s MIME type. Only "
+        "first data element can be transfered!",
+        dragItems, mimeFlavor.get());
+  }
+#endif
+
+  nsCOMPtr<nsITransferable> item = do_QueryElementAt(mSourceDataItems, 0);
+  if (!item) {
+    LOGDRAGSERVICE("  Failed to get SourceDataItems!");
+    return;
+  }
+
+  if (mimeFlavor.EqualsLiteral(kTextMime) ||
+      mimeFlavor.EqualsLiteral(gTextPlainUTF8Type)) {
+    SourceDataGetText(item, nsDependentCString(kTextMime),
+                      /* aNeedToDoConversionToPlainText */ true,
+                      aSelectionData);
+    // no fallback for text mime types
+    return;
+  }
+  // Someone is asking for the special Direct Save Protocol type.
+  else if (mimeFlavor.EqualsLiteral(gXdndDirectSaveType)) {
+    SourceDataGetXDND(item, aContext, aSelectionData);
+    // no fallback for XDND mime types
+    return;
+  } else if (mimeFlavor.EqualsLiteral(kPNGImageMime) ||
+             mimeFlavor.EqualsLiteral(kJPEGImageMime) ||
+             mimeFlavor.EqualsLiteral(kJPGImageMime) ||
+             mimeFlavor.EqualsLiteral(kGIFImageMime)) {
+    // no fallback for image mime types
+    SourceDataGetImage(item, aSelectionData);
+    return;
+  } else if (mimeFlavor.EqualsLiteral(gMozUrlType)) {
+    // Someone was asking for _NETSCAPE_URL. We need to get it from
+    // transferable as x-moz-url and convert it to plain text.
+    // No need to check
+    if (SourceDataGetText(item, nsDependentCString(kURLMime),
+                          /* aNeedToDoConversionToPlainText */ true,
+                          aSelectionData)) {
+      return;
+    }
+  }
+  // Just try to get and set whatever we're asked for.
+  SourceDataGetText(item, mimeFlavor,
+                    /* aNeedToDoConversionToPlainText */ false, aSelectionData);
+}
+
+void nsDragService::SourceBeginDrag(GdkDragContext* aContext) {
+  LOGDRAGSERVICE("nsDragService::SourceBeginDrag(%p)\n", aContext);
+
+  nsCOMPtr<nsITransferable> transferable =
+      do_QueryElementAt(mSourceDataItems, 0);
+  if (!transferable) return;
+
+  nsTArray<nsCString> flavors;
+  nsresult rv = transferable->FlavorsTransferableCanImport(flavors);
+  NS_ENSURE_SUCCESS(rv, );
+
+  for (uint32_t i = 0; i < flavors.Length(); ++i) {
+    if (flavors[i].EqualsLiteral(kFilePromiseDestFilename)) {
+      nsCOMPtr<nsISupports> data;
+      rv = transferable->GetTransferData(kFilePromiseDestFilename,
+                                         getter_AddRefs(data));
+      if (NS_FAILED(rv)) {
+        LOGDRAGSERVICE("  transferable doesn't contain '%s",
+                       kFilePromiseDestFilename);
+        return;
+      }
+
+      nsCOMPtr<nsISupportsString> fileName = do_QueryInterface(data);
+      if (!fileName) {
+        LOGDRAGSERVICE("  failed to get file name");
+        return;
+      }
+
+      nsAutoString fileNameStr;
+      fileName->GetData(fileNameStr);
+
+      nsCString fileNameCStr;
+      CopyUTF16toUTF8(fileNameStr, fileNameCStr);
+
+      GdkAtom property = gdk_atom_intern(gXdndDirectSaveType, FALSE);
+      GdkAtom type = gdk_atom_intern(kTextMime, FALSE);
+
+      gdk_property_change(gdk_drag_context_get_source_window(aContext),
+                          property, type, 8, GDK_PROP_MODE_REPLACE,
+                          (const guchar*)fileNameCStr.get(),
+                          fileNameCStr.Length());
+      break;
+    }
+  }
+}
+
+void nsDragService::SetDragIcon(GdkDragContext* aContext) {
+  if (!mHasImage && !mSelection) return;
+
+  LOGDRAGSERVICE("nsDragService::SetDragIcon(%p)", aContext);
+
+  LayoutDeviceIntRect dragRect;
+  nsPresContext* pc;
+  RefPtr<SourceSurface> surface;
+  DrawDrag(mSourceNode, mRegion, mScreenPosition, &dragRect, &surface, &pc);
+  if (!pc) {
+    LOGDRAGSERVICE("  PresContext is missing!");
+    return;
+  }
+
+  const auto screenPoint =
+      LayoutDeviceIntPoint::Round(mScreenPosition * pc->CSSToDevPixelScale());
+  int32_t offsetX = screenPoint.x - dragRect.x;
+  int32_t offsetY = screenPoint.y - dragRect.y;
+
+  // If a popup is set as the drag image, use its widget. Otherwise, use
+  // the surface that DrawDrag created.
+  //
+  // XXX: Disable drag popups on GTK 3.19.4 and above: see bug 1264454.
+  //      Fix this once a new GTK version ships that does not destroy our
+  //      widget in gtk_drag_set_icon_widget.
+  //      This is fixed in GTK 3.24
+  //      by
+  //      https://gitlab.gnome.org/GNOME/gtk/-/commit/c27c4e2048acb630feb24c31288f802345e99f4c
+  bool gtk_drag_set_icon_widget_is_working =
+      gtk_check_version(3, 19, 4) != nullptr ||
+      gtk_check_version(3, 24, 0) == nullptr;
+  if (mDragPopup && gtk_drag_set_icon_widget_is_working) {
+    GtkWidget* gtkWidget = nullptr;
+    nsIFrame* frame = mDragPopup->GetPrimaryFrame();
+    if (frame) {
+      // DrawDrag ensured that this is a popup frame.
+      nsCOMPtr<nsIWidget> widget = frame->GetNearestWidget();
+      if (widget) {
+        gtkWidget = (GtkWidget*)widget->GetNativeData(NS_NATIVE_SHELLWIDGET);
+        if (gtkWidget) {
+          // When mDragPopup has a parent it's already attached to D&D context.
+          // That may happens when D&D operation is aborted but not finished
+          // on Gtk side yet so let's remove it now.
+          if (GtkWidget* parent = gtk_widget_get_parent(gtkWidget)) {
+            gtk_container_remove(GTK_CONTAINER(parent), gtkWidget);
+          }
+          LOGDRAGSERVICE("  set drag popup [%p]", widget.get());
+          OpenDragPopup();
+          gtk_drag_set_icon_widget(aContext, gtkWidget, offsetX, offsetY);
+          return;
+        } else {
+          LOGDRAGSERVICE("  NS_NATIVE_SHELLWIDGET is missing!");
+        }
+      } else {
+        LOGDRAGSERVICE("  NearestWidget is missing!");
+      }
+    } else {
+      LOGDRAGSERVICE("  PrimaryFrame is missing!");
+    }
+  }
+
+  if (surface) {
+    LOGDRAGSERVICE("  We have a surface");
+    if (!SetAlphaPixmap(surface, aContext, offsetX, offsetY, dragRect)) {
+      RefPtr<GdkPixbuf> dragPixbuf = nsImageToPixbuf::SourceSurfaceToPixbuf(
+          surface, dragRect.width, dragRect.height);
+      if (dragPixbuf) {
+        LOGDRAGSERVICE("  set drag pixbuf");
+        gtk_drag_set_icon_pixbuf(aContext, dragPixbuf, offsetX, offsetY);
+      } else {
+        LOGDRAGSERVICE("  SourceSurfaceToPixbuf failed!");
+      }
+    }
+  } else {
+    LOGDRAGSERVICE("  Surface is missing!");
+  }
+}
+
+static void invisibleSourceDragBegin(GtkWidget* aWidget,
+                                     GdkDragContext* aContext, gpointer aData) {
+  LOGDRAGSERVICESTATIC("invisibleSourceDragBegin (%p)", aContext);
+  nsDragService* dragService = (nsDragService*)aData;
+
+  dragService->SourceBeginDrag(aContext);
+  dragService->SetDragIcon(aContext);
+}
+
+static void invisibleSourceDragDataGet(GtkWidget* aWidget,
+                                       GdkDragContext* aContext,
+                                       GtkSelectionData* aSelectionData,
+                                       guint aInfo, guint32 aTime,
+                                       gpointer aData) {
+  LOGDRAGSERVICESTATIC("invisibleSourceDragDataGet (%p)", aContext);
+  nsDragService* dragService = (nsDragService*)aData;
+  dragService->SourceDataGet(aWidget, aContext, aSelectionData, aTime);
+}
+
+static gboolean invisibleSourceDragFailed(GtkWidget* aWidget,
+                                          GdkDragContext* aContext,
+                                          gint aResult, gpointer aData) {
+#ifdef MOZ_WAYLAND
+  // Wayland and X11 uses different drag results here. When drag target is
+  // missing X11 passes GDK_DRAG_CANCEL_NO_TARGET
+  // (from gdk_dnd_handle_button_event()/gdkdnd-x11.c)
+  // as backend X11 has info about other application windows.
+  // Wayland does not have such info so it always passes
+  // GDK_DRAG_CANCEL_ERROR error code
+  // (see data_source_cancelled/gdkselection-wayland.c).
+  // Bug 1527976
+  if (widget::GdkIsWaylandDisplay() && aResult == GTK_DRAG_RESULT_ERROR) {
+    for (GList* tmp = gdk_drag_context_list_targets(aContext); tmp;
+         tmp = tmp->next) {
+      GdkAtom atom = GDK_POINTER_TO_ATOM(tmp->data);
+      GUniquePtr<gchar> name(gdk_atom_name(atom));
+      if (name && !strcmp(name.get(), gTabDropType)) {
+        aResult = GTK_DRAG_RESULT_NO_TARGET;
+        LOGDRAGSERVICESTATIC("invisibleSourceDragFailed(%p): Wayland tab drop",
+                             aContext);
+        break;
+      }
+    }
+  }
+#endif
+  LOGDRAGSERVICESTATIC("invisibleSourceDragFailed(%p) %s", aContext,
+                       kGtkDragResults[aResult]);
+  nsDragService* dragService = (nsDragService*)aData;
+  // End the drag session now (rather than waiting for the drag-end signal)
+  // so that operations performed on dropEffect == none can start immediately
+  // rather than waiting for the drag-failed animation to finish.
+  dragService->SourceEndDragSession(aContext, aResult);
+
+  // We should return TRUE to disable the drag-failed animation iff the
+  // source performed an operation when dropEffect was none, but the handler
+  // of the dragend DOM event doesn't provide this information.
+  return FALSE;
+}
+
+static void invisibleSourceDragEnd(GtkWidget* aWidget, GdkDragContext* aContext,
+                                   gpointer aData) {
+  LOGDRAGSERVICESTATIC("invisibleSourceDragEnd(%p)", aContext);
+  nsDragService* dragService = (nsDragService*)aData;
+
+  // The drag has ended.  Release the hostages!
+  dragService->SourceEndDragSession(aContext, GTK_DRAG_RESULT_SUCCESS);
+}
+
+// The following methods handle responding to GTK drag signals and
+// tracking state between these signals.
+//
+// In general, GTK does not expect us to run the event loop while handling its
+// drag signals, however our drag event handlers may run the
+// event loop, most often to fetch information about the drag data.
+//
+// GTK, for example, uses the return value from drag-motion signals to
+// determine whether drag-leave signals should be sent.  If an event loop is
+// run during drag-motion the XdndLeave message can get processed but when GTK
+// receives the message it does not yet know that it needs to send the
+// drag-leave signal to our widget.
+//
+// After a drag-drop signal, we need to reply with gtk_drag_finish().
+// However, gtk_drag_finish should happen after the drag-drop signal handler
+// returns so that when the Motif drag protocol is used, the
+// XmTRANSFER_SUCCESS during gtk_drag_finish is sent after the XmDROP_START
+// reply sent on return from the drag-drop signal handler.
+//
+// Similarly drag-end for a successful drag and drag-failed are not good
+// times to run a nested event loop as gtk_drag_drop_finished() and
+// gtk_drag_source_info_destroy() don't gtk_drag_clear_source_info() or remove
+// drop_timeout until after at least the first of these signals is sent.
+// Processing other events (e.g. a slow GDK_DROP_FINISHED reply, or the drop
+// timeout) could cause gtk_drag_drop_finished to be called again with the
+// same GtkDragSourceInfo, which won't like being destroyed twice.
+//
+// Therefore we reply to the signals immediately and schedule a task to
+// dispatch the Gecko events, which may run the event loop.
+//
+// Action in response to drag-leave signals is also delayed until the event
+// loop runs again so that we find out whether a drag-drop signal follows.
+//
+// A single task is scheduled to manage responses to all three GTK signals.
+// If further signals are received while the task is scheduled, the scheduled
+// response is updated, sometimes effectively compressing successive signals.
+//
+// No Gecko drag events are dispatched (during nested event loops) while other
+// Gecko drag events are in flight.  This helps event handlers that may not
+// expect nested events, while accessing an event's dataTransfer for example.
+
+gboolean nsDragService::ScheduleMotionEvent(nsWindow* aWindow,
+                                            GdkDragContext* aDragContext,
+                                            LayoutDeviceIntPoint aWindowPoint,
+                                            guint aTime) {
+  if (aDragContext && mScheduledTask == eDragTaskMotion) {
+    // The drag source has sent another motion message before we've
+    // replied to the previous.  That shouldn't happen with Xdnd.  The
+    // spec for Motif drags is less clear, but we'll just update the
+    // scheduled task with the new position reply only to the most
+    // recent message.
+    NS_WARNING("Drag Motion message received before previous reply was sent");
+  }
+
+  // Returning TRUE means we'll reply with a status message, unless we first
+  // get a leave.
+  return Schedule(eDragTaskMotion, aWindow, aDragContext, aWindowPoint, aTime);
+}
+
+void nsDragService::ScheduleLeaveEvent() {
+  // We don't know at this stage whether a drop signal will immediately
+  // follow.  If the drop signal gets sent it will happen before we return
+  // to the main loop and the scheduled leave task will be replaced.
+  if (!Schedule(eDragTaskLeave, nullptr, nullptr, LayoutDeviceIntPoint(), 0)) {
+    NS_WARNING("Drag leave after drop");
+  }
+}
+
+gboolean nsDragService::ScheduleDropEvent(nsWindow* aWindow,
+                                          GdkDragContext* aDragContext,
+                                          LayoutDeviceIntPoint aWindowPoint,
+                                          guint aTime) {
+  if (!Schedule(eDragTaskDrop, aWindow, aDragContext, aWindowPoint, aTime)) {
+    NS_WARNING("Additional drag drop ignored");
+    return FALSE;
+  }
+
+  SetDragEndPoint(aWindowPoint);
+
+  // We'll reply with gtk_drag_finish().
+  return TRUE;
+}
+
+#ifdef MOZ_LOGGING
+const char* nsDragService::GetDragServiceTaskName(DragTask aTask) {
+  static const char* taskNames[] = {"eDragTaskNone", "eDragTaskMotion",
+                                    "eDragTaskLeave", "eDragTaskDrop",
+                                    "eDragTaskSourceEnd"};
+  MOZ_ASSERT(size_t(aTask) < ArrayLength(taskNames));
+  return taskNames[aTask];
+}
+#endif
+
+gboolean nsDragService::Schedule(DragTask aTask, nsWindow* aWindow,
+                                 GdkDragContext* aDragContext,
+                                 LayoutDeviceIntPoint aWindowPoint,
+                                 guint aTime) {
+  // If there is an existing leave or motion task scheduled, then that
+  // will be replaced.  When the new task is run, it will dispatch
+  // any necessary leave or motion events.
+
+  // If aTask is eDragTaskSourceEnd, then it will replace even a scheduled
+  // drop event (which could happen if the drop event has not been processed
+  // within the allowed time).  Otherwise, if we haven't yet run a scheduled
+  // drop or end task, just say that we are not ready to receive another
+  // drop.
+  LOGDRAGSERVICE("nsDragService::Schedule(%p) task %s window %p\n",
+                 aDragContext, GetDragServiceTaskName(aTask), aWindow);
+
+  if (mScheduledTask == eDragTaskSourceEnd ||
+      (mScheduledTask == eDragTaskDrop && aTask != eDragTaskSourceEnd)) {
+    LOGDRAGSERVICE("   task does not fit recent task %s, quit!\n",
+                   GetDragServiceTaskName(mScheduledTask));
+    return FALSE;
+  }
+
+  mScheduledTask = aTask;
+  mPendingWindow = aWindow;
+  mPendingDragContext = aDragContext;
+  mPendingWindowPoint = aWindowPoint;
+  mPendingTime = aTime;
+
+  if (!mTaskSource) {
+    // High priority is used here because we want to process motion events
+    // right after drag_motion event handler which is called by Gtk.
+    // An ideal scenario is to call TaskDispatchCallback() directly here
+    // but we can't do that. TaskDispatchCallback() spins gtk event loop
+    // while nsDragService::Schedule() is already called from event loop
+    // (by drag_motion* gtk_widget events) so that direct call will cause
+    // nested recursion.
+    mTaskSource = g_timeout_add_full(G_PRIORITY_HIGH, 0, TaskDispatchCallback,
+                                     this, nullptr);
+  }
+
+  // We need to reply to drag_motion event on Wayland immediately,
+  // see Bug 1730203.
+  if (widget::GdkIsWaylandDisplay() && mScheduledTask == eDragTaskMotion) {
+    UpdateDragAction(aDragContext);
+    ReplyToDragMotion(aDragContext, aTime);
+  }
+
+  return TRUE;
+}
+
+gboolean nsDragService::TaskDispatchCallback(gpointer data) {
+  RefPtr<nsDragService> dragService = static_cast<nsDragService*>(data);
+  AutoEventLoop loop(dragService);
+  return dragService->RunScheduledTask();
+}
+
+gboolean nsDragService::RunScheduledTask() {
+  LOGDRAGSERVICE(
+      "nsDragService::RunScheduledTask() task %s mTargetWindow %p "
+      "mPendingWindow %p\n",
+      GetDragServiceTaskName(mScheduledTask), mTargetWindow.get(),
+      mPendingWindow.get());
+
+  // Don't run RunScheduledTask() twice. As we use it in main thread only
+  // we don't need to be thread safe here.
+  if (mScheduledTaskIsRunning) {
+    LOGDRAGSERVICE("  sheduled task is already running, quit.");
+    return FALSE;
+  }
+  AutoRestore<bool> guard(mScheduledTaskIsRunning);
+  mScheduledTaskIsRunning = true;
+
+  if (mTargetWindow && mTargetWindow != mPendingWindow) {
+    LOGDRAGSERVICE("  dispatch eDragExit (%p)\n", mTargetWindow.get());
+    mTargetWindow->DispatchDragEvent(eDragExit, mTargetWindowPoint, 0);
+
+    if (!mSourceNode) {
+      // The drag that was initiated in a different app. End the drag
+      // session, since we're done with it for now (until the user drags
+      // back into this app).
+      EndDragSession(false, GetCurrentModifiers());
+    }
+  }
+
+  // It is possible that the pending state has been updated during dispatch
+  // of the leave event.  That's fine.
+
+  // Now we collect the pending state because, from this point on, we want
+  // to use the same state for all events dispatched.  All state is updated
+  // so that when other tasks are scheduled during dispatch here, this
+  // task is considered to have already been run.
+  bool positionHasChanged = mPendingWindow != mTargetWindow ||
+                            mPendingWindowPoint != mTargetWindowPoint;
+  DragTask task = mScheduledTask;
+  mScheduledTask = eDragTaskNone;
+  mTargetWindow = std::move(mPendingWindow);
+  mTargetWindowPoint = mPendingWindowPoint;
+
+  if (task == eDragTaskLeave || task == eDragTaskSourceEnd) {
+    LOGDRAGSERVICE("  quit, selected task %s\n", GetDragServiceTaskName(task));
+    if (task == eDragTaskSourceEnd) {
+      // Dispatch drag end events.
+      EndDragSession(true, GetCurrentModifiers());
+    }
+
+    // Nothing more to do
+    // Returning false removes the task source from the event loop.
+    mTaskSource = 0;
+    return FALSE;
+  }
+
+  // This may be the start of a destination drag session.
+  StartDragSession();
+
+  // mTargetWidget may be nullptr if the window has been destroyed.
+  // (The leave event is not scheduled if a drop task is still scheduled.)
+  // We still reply appropriately to indicate that the drop will or didn't
+  // succeeed.
+  mTargetWidget = mTargetWindow ? mTargetWindow->GetGtkWidget() : nullptr;
+  LOGDRAGSERVICE("  start drag session mTargetWindow %p mTargetWidget %p\n",
+                 mTargetWindow.get(), mTargetWidget.get());
+  LOGDRAGSERVICE("  mPendingDragContext %p => mTargetDragContext %p\n",
+                 mPendingDragContext.get(), mTargetDragContext.get());
+  mTargetDragContext = std::move(mPendingDragContext);
+  mTargetTime = mPendingTime;
+
+  // http://www.whatwg.org/specs/web-apps/current-work/multipage/dnd.html#drag-and-drop-processing-model
+  // (as at 27 December 2010) indicates that a "drop" event should only be
+  // fired (at the current target element) if the current drag operation is
+  // not none.  The current drag operation will only be set to a non-none
+  // value during a "dragover" event.
+  //
+  // If the user has ended the drag before any dragover events have been
+  // sent, then the spec recommends skipping the drop (because the current
+  // drag operation is none).  However, here we assume that, by releasing
+  // the mouse button, the user has indicated that they want to drop, so we
+  // proceed with the drop where possible.
+  //
+  // In order to make the events appear to content in the same way as if the
+  // spec is being followed we make sure to dispatch a "dragover" event with
+  // appropriate coordinates and check canDrop before the "drop" event.
+  //
+  // When the Xdnd protocol is used for source/destination communication (as
+  // should be the case with GTK source applications) a dragover event
+  // should have already been sent during the drag-motion signal, which
+  // would have already been received because XdndDrop messages do not
+  // contain a position.  However, we can't assume the same when the Motif
+  // protocol is used.
+  if (task == eDragTaskMotion || positionHasChanged) {
+    LOGDRAGSERVICE("  process motion event\n");
+    UpdateDragAction();
+    TakeDragEventDispatchedToChildProcess();  // Clear the old value.
+    DispatchMotionEvents();
+    if (task == eDragTaskMotion) {
+      if (TakeDragEventDispatchedToChildProcess()) {
+        mTargetDragContextForRemote = mTargetDragContext;
+      } else {
+        // Reply to tell the source whether we can drop and what
+        // action would be taken.
+        ReplyToDragMotion();
+      }
+    }
+  }
+
+  if (task == eDragTaskDrop) {
+    LOGDRAGSERVICE("  process drop task\n");
+    gboolean success = DispatchDropEvent();
+
+    // Perhaps we should set the del parameter to TRUE when the drag
+    // action is move, but we don't know whether the data was successfully
+    // transferred.
+    if (mTargetDragContext) {
+      LOGDRAGSERVICE("  drag finished\n");
+      gtk_drag_finish(mTargetDragContext, success,
+                      /* del = */ FALSE, mTargetTime);
+    }
+    // Make sure to end the drag session. If this drag started in a
+    // different app, we won't get a drag_end signal to end it from.
+    EndDragSession(true, GetCurrentModifiers());
+  }
+
+  // We're done with the drag context.
+  LOGDRAGSERVICE("  clear mTargetWindow mTargetWidget and other data\n");
+  mTargetWidget = nullptr;
+  mTargetDragContext = nullptr;
+
+  // If we got another drag signal while running the sheduled task, that
+  // must have happened while running a nested event loop.  Leave the task
+  // source on the event loop.
+  if (mScheduledTask != eDragTaskNone) return TRUE;
+
+  // We have no task scheduled.
+  // Returning false removes the task source from the event loop.
+  LOGDRAGSERVICE("  remove task source\n");
+  mTaskSource = 0;
+  return FALSE;
+}
+
+// This will update the drag action based on the information in the
+// drag context.  Gtk gets this from a combination of the key settings
+// and what the source is offering.
+
+void nsDragService::UpdateDragAction(GdkDragContext* aDragContext) {
+  // This doesn't look right.  dragSession.dragAction is used by
+  // nsContentUtils::SetDataTransferInEvent() to set the initial
+  // dataTransfer.dropEffect, so GdkDragContext::suggested_action would be
+  // more appropriate.  GdkDragContext::actions should be used to set
+  // dataTransfer.effectAllowed, which doesn't currently happen with
+  // external sources.
+  LOGDRAGSERVICE("nsDragService::UpdateDragAction(%p)", aDragContext);
+
+  // default is to do nothing
+  int action = nsIDragService::DRAGDROP_ACTION_NONE;
+  GdkDragAction gdkAction = GDK_ACTION_DEFAULT;
+  if (aDragContext) {
+    gdkAction = gdk_drag_context_get_actions(aDragContext);
+    LOGDRAGSERVICE("  gdk_drag_context_get_actions() returns 0x%X", gdkAction);
+
+    // When D&D modifiers (CTRL/SHIFT) are involved,
+    // gdk_drag_context_get_actions() on X11 returns selected action but
+    // Wayland returns all allowed actions.
+
+    // So we need to call gdk_drag_context_get_selected_action() on Wayland
+    // to get potential D&D modifier.
+    // gdk_drag_context_get_selected_action() is also affected by
+    // gdk_drag_status(), see nsDragService::ReplyToDragMotion().
+    if (widget::GdkIsWaylandDisplay()) {
+      GdkDragAction gdkActionSelected =
+          gdk_drag_context_get_selected_action(aDragContext);
+      LOGDRAGSERVICE("  gdk_drag_context_get_selected_action() returns 0x%X",
+                     gdkActionSelected);
+      if (gdkActionSelected) {
+        gdkAction = gdkActionSelected;
+      }
+    }
+  }
+
+  // set the default just in case nothing matches below
+  if (gdkAction & GDK_ACTION_DEFAULT) {
+    LOGDRAGSERVICE("  set default move");
+    action = nsIDragService::DRAGDROP_ACTION_MOVE;
+  }
+  // first check to see if move is set
+  if (gdkAction & GDK_ACTION_MOVE) {
+    LOGDRAGSERVICE("  set explicit move");
+    action = nsIDragService::DRAGDROP_ACTION_MOVE;
+  } else if (gdkAction & GDK_ACTION_LINK) {
+    // then fall to the others
+    LOGDRAGSERVICE("  set explicit link");
+    action = nsIDragService::DRAGDROP_ACTION_LINK;
+  } else if (gdkAction & GDK_ACTION_COPY) {
+    // copy is ctrl
+    LOGDRAGSERVICE("  set explicit copy");
+    action = nsIDragService::DRAGDROP_ACTION_COPY;
+  }
+
+  // update the drag information
+  SetDragAction(action);
+}
+
+void nsDragService::UpdateDragAction() { UpdateDragAction(mTargetDragContext); }
+
+NS_IMETHODIMP
+nsDragService::UpdateDragEffect() {
+  LOGDRAGSERVICE("nsDragService::UpdateDragEffect() from e10s child process");
+  if (mTargetDragContextForRemote) {
+    ReplyToDragMotion(mTargetDragContextForRemote, mTargetTime);
+    mTargetDragContextForRemote = nullptr;
+  }
+  return NS_OK;
+}
+
+void nsDragService::ReplyToDragMotion() {
+  if (mTargetDragContext) {
+    ReplyToDragMotion(mTargetDragContext, mTargetTime);
+  }
+}
+
+void nsDragService::DispatchMotionEvents() {
+  FireDragEventAtSource(eDrag, GetCurrentModifiers());
+  if (mTargetWindow) {
+    mTargetWindow->DispatchDragEvent(eDragOver, mTargetWindowPoint,
+                                     mTargetTime);
+  }
+}
+
+// Returns true if the drop was successful
+gboolean nsDragService::DispatchDropEvent() {
+  // We need to check IsDestroyed here because the nsRefPtr
+  // only protects this from being deleted, it does NOT protect
+  // against nsView::~nsView() calling Destroy() on it, bug 378273.
+  if (!mTargetWindow || mTargetWindow->IsDestroyed()) {
+    return FALSE;
+  }
+
+  EventMessage msg = mCanDrop ? eDrop : eDragExit;
+
+  mTargetWindow->DispatchDragEvent(msg, mTargetWindowPoint, mTargetTime);
+
+  return mCanDrop;
+}
+
+/* static */
+uint32_t nsDragService::GetCurrentModifiers() {
+  return mozilla::widget::KeymapWrapper::ComputeCurrentKeyModifiers();
+}
+
+#undef LOGDRAGSERVICE
diff --git a/widget/gtk/nsDragService.h b/widget/gtk/nsDragService.h
new file mode 100644
index 0000000000..8a45b7b8ed
--- /dev/null
+++ b/widget/gtk/nsDragService.h
@@ -0,0 +1,268 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=4 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsDragService_h__
+#define nsDragService_h__
+
+#include "mozilla/RefPtr.h"
+#include "nsBaseDragService.h"
+#include "nsCOMArray.h"
+#include "nsIObserver.h"
+#include <gtk/gtk.h>
+#include "nsITimer.h"
+#include "GUniquePtr.h"
+
+class nsICookieJarSettings;
+class nsWindow;
+
+namespace mozilla {
+namespace gfx {
+class SourceSurface;
+}
+}  // namespace mozilla
+
+/**
+ * Native GTK DragService wrapper
+ */
+
+class nsDragService final : public nsBaseDragService, public nsIObserver {
+ public:
+  nsDragService();
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIOBSERVER
+
+  // nsBaseDragService
+  MOZ_CAN_RUN_SCRIPT virtual nsresult InvokeDragSessionImpl(
+      nsIArray* anArrayTransferables,
+      const mozilla::Maybe<mozilla::CSSIntRegion>& aRegion,
+      uint32_t aActionType) override;
+  // nsIDragService
+  MOZ_CAN_RUN_SCRIPT NS_IMETHOD InvokeDragSession(
+      nsINode* aDOMNode, nsIPrincipal* aPrincipal,
+      nsIContentSecurityPolicy* aCsp, nsICookieJarSettings* aCookieJarSettings,
+      nsIArray* anArrayTransferables, uint32_t aActionType,
+      nsContentPolicyType aContentPolicyType) override;
+  NS_IMETHOD StartDragSession() override;
+  MOZ_CAN_RUN_SCRIPT NS_IMETHOD EndDragSession(bool aDoneDrag,
+                                               uint32_t aKeyModifiers) override;
+
+  // nsIDragSession
+  NS_IMETHOD SetCanDrop(bool aCanDrop) override;
+  NS_IMETHOD GetCanDrop(bool* aCanDrop) override;
+  NS_IMETHOD GetNumDropItems(uint32_t* aNumItems) override;
+  NS_IMETHOD GetData(nsITransferable* aTransferable,
+                     uint32_t aItemIndex) override;
+  NS_IMETHOD IsDataFlavorSupported(const char* aDataFlavor,
+                                   bool* _retval) override;
+
+  // Update Drag&Drop state according child process state.
+  // UpdateDragEffect() is called by IPC bridge when child process
+  // accepts/denies D&D operation and uses stored
+  // mTargetDragContextForRemote context.
+  NS_IMETHOD UpdateDragEffect() override;
+
+  // Methods called from nsWindow to handle responding to GTK drag
+  // destination signals
+
+  static already_AddRefed<nsDragService> GetInstance();
+
+  void TargetDataReceived(GtkWidget* aWidget, GdkDragContext* aContext, gint aX,
+                          gint aY, GtkSelectionData* aSelection_data,
+                          guint aInfo, guint32 aTime);
+
+  gboolean ScheduleMotionEvent(nsWindow* aWindow, GdkDragContext* aDragContext,
+                               mozilla::LayoutDeviceIntPoint aWindowPoint,
+                               guint aTime);
+  void ScheduleLeaveEvent();
+  gboolean ScheduleDropEvent(nsWindow* aWindow, GdkDragContext* aDragContext,
+                             mozilla::LayoutDeviceIntPoint aWindowPoint,
+                             guint aTime);
+
+  nsWindow* GetMostRecentDestWindow() {
+    return mScheduledTask == eDragTaskNone ? mTargetWindow : mPendingWindow;
+  }
+
+  //  END PUBLIC API
+
+  // These methods are public only so that they can be called from functions
+  // with C calling conventions.  They are called for drags started with the
+  // invisible widget.
+  void SourceEndDragSession(GdkDragContext* aContext, gint aResult);
+  void SourceDataGet(GtkWidget* widget, GdkDragContext* context,
+                     GtkSelectionData* selection_data, guint32 aTime);
+  bool SourceDataGetText(nsITransferable* aItem, const nsACString& aMIMEType,
+                         bool aNeedToDoConversionToPlainText,
+                         GtkSelectionData* aSelectionData);
+  void SourceDataGetImage(nsITransferable* aItem,
+                          GtkSelectionData* aSelectionData);
+  void SourceDataGetXDND(nsITransferable* aItem, GdkDragContext* aContext,
+                         GtkSelectionData* aSelectionData);
+  void SourceDataGetUriList(GdkDragContext* aContext,
+                            GtkSelectionData* aSelectionData,
+                            uint32_t aDragItems);
+  bool SourceDataAppendURLFileItem(nsACString& aURI, nsITransferable* aItem);
+  bool SourceDataAppendURLItem(nsITransferable* aItem, bool aExternalDrop,
+                               nsACString& aURI);
+
+  void SourceBeginDrag(GdkDragContext* aContext);
+
+  // set the drag icon during drag-begin
+  void SetDragIcon(GdkDragContext* aContext);
+
+  class AutoEventLoop {
+    RefPtr<nsDragService> mService;
+
+   public:
+    explicit AutoEventLoop(RefPtr<nsDragService> aService)
+        : mService(std::move(aService)) {
+      mService->mEventLoopDepth++;
+    }
+    ~AutoEventLoop() { mService->mEventLoopDepth--; }
+  };
+  int GetLoopDepth() const { return mEventLoopDepth; };
+
+ protected:
+  virtual ~nsDragService();
+
+ private:
+  // mScheduledTask indicates what signal has been received from GTK and
+  // so what needs to be dispatched when the scheduled task is run.  It is
+  // eDragTaskNone when there is no task scheduled (but the
+  // previous task may still not have finished running).
+  enum DragTask {
+    eDragTaskNone,
+    eDragTaskMotion,
+    eDragTaskLeave,
+    eDragTaskDrop,
+    eDragTaskSourceEnd
+  };
+  DragTask mScheduledTask;
+  // mTaskSource is the GSource id for the task that is either scheduled
+  // or currently running.  It is 0 if no task is scheduled or running.
+  guint mTaskSource;
+  bool mScheduledTaskIsRunning;
+
+  // Where the drag begins. We need to keep it open on Wayland.
+  RefPtr<nsWindow> mSourceWindow;
+
+  // target/destination side vars
+  // These variables keep track of the state of the current drag.
+
+  // mPendingWindow, mPendingWindowPoint, mPendingDragContext, and
+  // mPendingTime, carry information from the GTK signal that will be used
+  // when the scheduled task is run.  mPendingWindow and mPendingDragContext
+  // will be nullptr if the scheduled task is eDragTaskLeave.
+  RefPtr<nsWindow> mPendingWindow;
+  mozilla::LayoutDeviceIntPoint mPendingWindowPoint;
+  RefPtr<GdkDragContext> mPendingDragContext;
+
+  // We cache all data for the current drag context,
+  // because waiting for the data in GetTargetDragData can be very slow.
+  nsTHashMap<nsCStringHashKey, nsTArray<uint8_t>> mCachedData;
+  // mCachedData are tied to mCachedDragContext. mCachedDragContext is not
+  // ref counted and may be already deleted on Gtk side.
+  // We used it for mCachedData invalidation only and can't be used for
+  // any D&D operation.
+  uintptr_t mCachedDragContext;
+
+  nsTHashMap<nsCStringHashKey, mozilla::GUniquePtr<gchar*>> mCachedUris;
+
+  guint mPendingTime;
+
+  // mTargetWindow and mTargetWindowPoint record the position of the last
+  // eDragTaskMotion or eDragTaskDrop task that was run or is still running.
+  // mTargetWindow is cleared once the drag has completed or left.
+  RefPtr<nsWindow> mTargetWindow;
+  mozilla::LayoutDeviceIntPoint mTargetWindowPoint;
+  // mTargetWidget and mTargetDragContext are set only while dispatching
+  // motion or drop events.  mTime records the corresponding timestamp.
+  RefPtr<GtkWidget> mTargetWidget;
+  RefPtr<GdkDragContext> mTargetDragContext;
+
+  // When we route D'n'D request to child process
+  // (by EventStateManager::DispatchCrossProcessEvent)
+  // we save GdkDragContext to mTargetDragContextForRemote.
+  // When we get a reply from child process we use
+  // the stored GdkDragContext to send reply to OS.
+  //
+  // We need to store GdkDragContext because mTargetDragContext is cleared
+  // after every D'n'D event.
+  RefPtr<GdkDragContext> mTargetDragContextForRemote;
+  guint mTargetTime;
+
+  // is it OK to drop on us?
+  bool mCanDrop;
+
+  // have we received our drag data?
+  bool mTargetDragDataReceived;
+  // last data received and its length
+  void* mTargetDragData;
+  uint32_t mTargetDragDataLen;
+  mozilla::GUniquePtr<gchar*> mTargetDragUris;
+  // is the current target drag context contain a list?
+  bool IsTargetContextList(void);
+  // this will get the native data from the last target given a
+  // specific flavor
+  void GetTargetDragData(GdkAtom aFlavor, nsTArray<nsCString>& aDropFlavors);
+  // this will reset all of the target vars
+  void TargetResetData(void);
+  // Ensure our data cache belongs to aDragContext and clear the cache if
+  // aDragContext is different than mCachedDragContext.
+  void EnsureCachedDataValidForContext(GdkDragContext* aDragContext);
+
+  // source side vars
+
+  // the source of our drags
+  GtkWidget* mHiddenWidget;
+  // our source data items
+  nsCOMPtr<nsIArray> mSourceDataItems;
+
+  // get a list of the sources in gtk's format
+  GtkTargetList* GetSourceList(void);
+
+  // attempts to create a semi-transparent drag image. Returns TRUE if
+  // successful, FALSE if not
+  bool SetAlphaPixmap(SourceSurface* aPixbuf, GdkDragContext* aContext,
+                      int32_t aXOffset, int32_t aYOffset,
+                      const mozilla::LayoutDeviceIntRect& dragRect);
+
+  gboolean Schedule(DragTask aTask, nsWindow* aWindow,
+                    GdkDragContext* aDragContext,
+                    mozilla::LayoutDeviceIntPoint aWindowPoint, guint aTime);
+
+  // Callback for g_idle_add_full() to run mScheduledTask.
+  MOZ_CAN_RUN_SCRIPT static gboolean TaskDispatchCallback(gpointer data);
+  MOZ_CAN_RUN_SCRIPT gboolean RunScheduledTask();
+  MOZ_CAN_RUN_SCRIPT void DispatchMotionEvents();
+  void ReplyToDragMotion(GdkDragContext* aDragContext, guint aTime);
+  void ReplyToDragMotion();
+  void UpdateDragAction(GdkDragContext* aDragContext);
+  void UpdateDragAction();
+
+#ifdef MOZ_LOGGING
+  const char* GetDragServiceTaskName(nsDragService::DragTask aTask);
+#endif
+  void GetDragFlavors(nsTArray<nsCString>& aFlavors);
+  gboolean DispatchDropEvent();
+  static uint32_t GetCurrentModifiers();
+
+  nsresult CreateTempFile(nsITransferable* aItem, nsACString& aURI);
+  bool RemoveTempFiles();
+  static gboolean TaskRemoveTempFiles(gpointer data);
+
+  // the url of the temporary file that has been created in the current drag
+  // session
+  nsTArray<nsCString> mTempFileUrls;
+  // stores all temporary files
+  nsCOMArray<nsIFile> mTemporaryFiles;
+  // timer to trigger deletion of temporary files
+  guint mTempFileTimerID;
+  // How deep we're nested in event loops
+  int mEventLoopDepth;
+};
+
+#endif  // nsDragService_h__
diff --git a/widget/gtk/nsFilePicker.cpp b/widget/gtk/nsFilePicker.cpp
new file mode 100644
index 0000000000..751da3dc6b
--- /dev/null
+++ b/widget/gtk/nsFilePicker.cpp
@@ -0,0 +1,785 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <dlfcn.h>
+#include <gtk/gtk.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "mozilla/Types.h"
+#include "AsyncDBus.h"
+#include "nsGtkUtils.h"
+#include "nsIFileURL.h"
+#include "nsIGIOService.h"
+#include "nsIURI.h"
+#include "nsIWidget.h"
+#include "nsIFile.h"
+#include "nsIStringBundle.h"
+#include "mozilla/Components.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/dom/Promise.h"
+
+#include "nsArrayEnumerator.h"
+#include "nsEnumeratorUtils.h"
+#include "nsNetUtil.h"
+#include "nsReadableUtils.h"
+#include "MozContainer.h"
+#include "WidgetUtilsGtk.h"
+
+#include "nsFilePicker.h"
+
+#undef LOG
+#ifdef MOZ_LOGGING
+#  include "mozilla/Logging.h"
+#  include "nsTArray.h"
+#  include "Units.h"
+extern mozilla::LazyLogModule gWidgetLog;
+#  define LOG(args) MOZ_LOG(gWidgetLog, mozilla::LogLevel::Debug, args)
+#else
+#  define LOG(args)
+#endif /* MOZ_LOGGING */
+
+using namespace mozilla;
+using mozilla::dom::Promise;
+
+#define MAX_PREVIEW_SIZE 180
+// bug 1184009
+#define MAX_PREVIEW_SOURCE_SIZE 4096
+
+nsIFile* nsFilePicker::mPrevDisplayDirectory = nullptr;
+
+void nsFilePicker::Shutdown() { NS_IF_RELEASE(mPrevDisplayDirectory); }
+
+static GtkFileChooserAction GetGtkFileChooserAction(nsIFilePicker::Mode aMode) {
+  GtkFileChooserAction action;
+
+  switch (aMode) {
+    case nsIFilePicker::modeSave:
+      action = GTK_FILE_CHOOSER_ACTION_SAVE;
+      break;
+
+    case nsIFilePicker::modeGetFolder:
+      action = GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER;
+      break;
+
+    case nsIFilePicker::modeOpen:
+    case nsIFilePicker::modeOpenMultiple:
+      action = GTK_FILE_CHOOSER_ACTION_OPEN;
+      break;
+
+    default:
+      NS_WARNING("Unknown nsIFilePicker mode");
+      action = GTK_FILE_CHOOSER_ACTION_OPEN;
+      break;
+  }
+
+  return action;
+}
+
+static void UpdateFilePreviewWidget(GtkFileChooser* file_chooser,
+                                    gpointer preview_widget_voidptr) {
+  GtkImage* preview_widget = GTK_IMAGE(preview_widget_voidptr);
+  char* image_filename = gtk_file_chooser_get_preview_filename(file_chooser);
+  struct stat st_buf;
+
+  if (!image_filename) {
+    gtk_file_chooser_set_preview_widget_active(file_chooser, FALSE);
+    return;
+  }
+
+  gint preview_width = 0;
+  gint preview_height = 0;
+  /* check type of file
+   * if file is named pipe, Open is blocking which may lead to UI
+   *  nonresponsiveness; if file is directory/socket, it also isn't
+   *  likely to get preview */
+  if (stat(image_filename, &st_buf) || (!S_ISREG(st_buf.st_mode))) {
+    g_free(image_filename);
+    gtk_file_chooser_set_preview_widget_active(file_chooser, FALSE);
+    return; /* stat failed or file is not regular */
+  }
+
+  GdkPixbufFormat* preview_format =
+      gdk_pixbuf_get_file_info(image_filename, &preview_width, &preview_height);
+  if (!preview_format || preview_width <= 0 || preview_height <= 0 ||
+      preview_width > MAX_PREVIEW_SOURCE_SIZE ||
+      preview_height > MAX_PREVIEW_SOURCE_SIZE) {
+    g_free(image_filename);
+    gtk_file_chooser_set_preview_widget_active(file_chooser, FALSE);
+    return;
+  }
+
+  GdkPixbuf* preview_pixbuf = nullptr;
+  // Only scale down images that are too big
+  if (preview_width > MAX_PREVIEW_SIZE || preview_height > MAX_PREVIEW_SIZE) {
+    preview_pixbuf = gdk_pixbuf_new_from_file_at_size(
+        image_filename, MAX_PREVIEW_SIZE, MAX_PREVIEW_SIZE, nullptr);
+  } else {
+    preview_pixbuf = gdk_pixbuf_new_from_file(image_filename, nullptr);
+  }
+
+  g_free(image_filename);
+
+  if (!preview_pixbuf) {
+    gtk_file_chooser_set_preview_widget_active(file_chooser, FALSE);
+    return;
+  }
+
+  GdkPixbuf* preview_pixbuf_temp = preview_pixbuf;
+  preview_pixbuf = gdk_pixbuf_apply_embedded_orientation(preview_pixbuf_temp);
+  g_object_unref(preview_pixbuf_temp);
+
+  // This is the easiest way to do center alignment without worrying about
+  // containers Minimum 3px padding each side (hence the 6) just to make things
+  // nice
+  gint x_padding =
+      (MAX_PREVIEW_SIZE + 6 - gdk_pixbuf_get_width(preview_pixbuf)) / 2;
+  gtk_misc_set_padding(GTK_MISC(preview_widget), x_padding, 0);
+
+  gtk_image_set_from_pixbuf(preview_widget, preview_pixbuf);
+  g_object_unref(preview_pixbuf);
+  gtk_file_chooser_set_preview_widget_active(file_chooser, TRUE);
+}
+
+static nsAutoCString MakeCaseInsensitiveShellGlob(const char* aPattern) {
+  // aPattern is UTF8
+  nsAutoCString result;
+  unsigned int len = strlen(aPattern);
+
+  for (unsigned int i = 0; i < len; i++) {
+    if (!g_ascii_isalpha(aPattern[i])) {
+      // non-ASCII characters will also trigger this path, so unicode
+      // is safely handled albeit case-sensitively
+      result.Append(aPattern[i]);
+      continue;
+    }
+
+    // add the lowercase and uppercase version of a character to a bracket
+    // match, so it matches either the lowercase or uppercase char.
+    result.Append('[');
+    result.Append(g_ascii_tolower(aPattern[i]));
+    result.Append(g_ascii_toupper(aPattern[i]));
+    result.Append(']');
+  }
+
+  return result;
+}
+
+NS_IMPL_ISUPPORTS(nsFilePicker, nsIFilePicker)
+
+nsFilePicker::nsFilePicker()
+    : mSelectedType(0), mAllowURLs(false), mFileChooserDelegate(nullptr) {
+  mUseNativeFileChooser =
+      widget::ShouldUsePortal(widget::PortalKind::FilePicker);
+}
+
+nsFilePicker::~nsFilePicker() = default;
+
+void ReadMultipleFiles(gpointer filename, gpointer array) {
+  nsCOMPtr<nsIFile> localfile;
+  nsresult rv =
+      NS_NewNativeLocalFile(nsDependentCString(static_cast<char*>(filename)),
+                            false, getter_AddRefs(localfile));
+  if (NS_SUCCEEDED(rv)) {
+    nsCOMArray<nsIFile>& files = *static_cast<nsCOMArray<nsIFile>*>(array);
+    files.AppendObject(localfile);
+  }
+
+  g_free(filename);
+}
+
+void nsFilePicker::ReadValuesFromFileChooser(void* file_chooser) {
+  mFiles.Clear();
+
+  if (mMode == nsIFilePicker::modeOpenMultiple) {
+    mFileURL.Truncate();
+
+    GSList* list =
+        gtk_file_chooser_get_filenames(GTK_FILE_CHOOSER(file_chooser));
+    g_slist_foreach(list, ReadMultipleFiles, static_cast<gpointer>(&mFiles));
+    g_slist_free(list);
+  } else {
+    gchar* filename = gtk_file_chooser_get_uri(GTK_FILE_CHOOSER(file_chooser));
+    mFileURL.Assign(filename);
+    g_free(filename);
+  }
+
+  GtkFileFilter* filter =
+      gtk_file_chooser_get_filter(GTK_FILE_CHOOSER(file_chooser));
+  GSList* filter_list =
+      gtk_file_chooser_list_filters(GTK_FILE_CHOOSER(file_chooser));
+
+  mSelectedType = static_cast<int16_t>(g_slist_index(filter_list, filter));
+  g_slist_free(filter_list);
+
+  // Remember last used directory.
+  nsCOMPtr<nsIFile> file;
+  GetFile(getter_AddRefs(file));
+  if (file) {
+    nsCOMPtr<nsIFile> dir;
+    file->GetParent(getter_AddRefs(dir));
+    if (dir) {
+      dir.swap(mPrevDisplayDirectory);
+    }
+  }
+}
+
+void nsFilePicker::InitNative(nsIWidget* aParent, const nsAString& aTitle) {
+  mParentWidget = aParent;
+  mTitle.Assign(aTitle);
+}
+
+NS_IMETHODIMP
+nsFilePicker::IsModeSupported(nsIFilePicker::Mode aMode, JSContext* aCx,
+                              Promise** aRetPromise) {
+#ifdef MOZ_ENABLE_DBUS
+  if (!widget::ShouldUsePortal(widget::PortalKind::FilePicker) ||
+      aMode != nsIFilePicker::modeGetFolder) {
+    return nsBaseFilePicker::IsModeSupported(aMode, aCx, aRetPromise);
+  }
+
+  const char kFreedesktopPortalName[] = "org.freedesktop.portal.Desktop";
+  const char kFreedesktopPortalPath[] = "/org/freedesktop/portal/desktop";
+  const char kFreedesktopPortalFileChooser[] =
+      "org.freedesktop.portal.FileChooser";
+
+  MOZ_ASSERT(aCx);
+  MOZ_ASSERT(aRetPromise);
+
+  nsIGlobalObject* globalObject = xpc::CurrentNativeGlobal(aCx);
+  if (NS_WARN_IF(!globalObject)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  ErrorResult result;
+  RefPtr<Promise> retPromise = Promise::Create(globalObject, result);
+  if (NS_WARN_IF(result.Failed())) {
+    return result.StealNSResult();
+  }
+
+  widget::CreateDBusProxyForBus(
+      G_BUS_TYPE_SESSION,
+      GDBusProxyFlags(G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS),
+      /* aInterfaceInfo = */ nullptr, kFreedesktopPortalName,
+      kFreedesktopPortalPath, kFreedesktopPortalFileChooser)
+      ->Then(
+          GetCurrentSerialEventTarget(), __func__,
+          [retPromise](RefPtr<GDBusProxy>&& aProxy) {
+            const char kFreedesktopPortalVersionProperty[] = "version";
+            // Folder selection was added in version 3 of xdg-desktop-portal
+            const uint32_t kFreedesktopPortalMinimumVersion = 3;
+            uint32_t foundVersion = 0;
+
+            RefPtr<GVariant> property =
+                dont_AddRef(g_dbus_proxy_get_cached_property(
+                    aProxy, kFreedesktopPortalVersionProperty));
+
+            if (property) {
+              foundVersion = g_variant_get_uint32(property);
+              LOG(("Found portal version: %u", foundVersion));
+            }
+
+            retPromise->MaybeResolve(foundVersion >=
+                                     kFreedesktopPortalMinimumVersion);
+          },
+          [retPromise](GUniquePtr<GError>&& aError) {
+            g_printerr("Failed to create DBUS proxy: %s\n", aError->message);
+            retPromise->MaybeReject(NS_ERROR_FAILURE);
+          });
+
+  retPromise.forget(aRetPromise);
+  return NS_OK;
+#else
+  return nsBaseFilePicker::IsModeSupported(aMode, aCx, aRetPromise);
+#endif
+}
+
+NS_IMETHODIMP
+nsFilePicker::AppendFilters(int32_t aFilterMask) {
+  mAllowURLs = !!(aFilterMask & filterAllowURLs);
+  return nsBaseFilePicker::AppendFilters(aFilterMask);
+}
+
+NS_IMETHODIMP
+nsFilePicker::AppendFilter(const nsAString& aTitle, const nsAString& aFilter) {
+  if (aFilter.EqualsLiteral("..apps")) {
+    // No platform specific thing we can do here, really....
+    return NS_OK;
+  }
+
+  nsAutoCString filter, name;
+  CopyUTF16toUTF8(aFilter, filter);
+  CopyUTF16toUTF8(aTitle, name);
+
+  mFilters.AppendElement(filter);
+  mFilterNames.AppendElement(name);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePicker::SetDefaultString(const nsAString& aString) {
+  mDefault = aString;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePicker::GetDefaultString(nsAString& aString) {
+  // Per API...
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsFilePicker::SetDefaultExtension(const nsAString& aExtension) {
+  mDefaultExtension = aExtension;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePicker::GetDefaultExtension(nsAString& aExtension) {
+  aExtension = mDefaultExtension;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePicker::GetFilterIndex(int32_t* aFilterIndex) {
+  *aFilterIndex = mSelectedType;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePicker::SetFilterIndex(int32_t aFilterIndex) {
+  mSelectedType = aFilterIndex;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePicker::GetFile(nsIFile** aFile) {
+  NS_ENSURE_ARG_POINTER(aFile);
+
+  *aFile = nullptr;
+  nsCOMPtr<nsIURI> uri;
+  nsresult rv = GetFileURL(getter_AddRefs(uri));
+  if (!uri) return rv;
+
+  nsCOMPtr<nsIFileURL> fileURL(do_QueryInterface(uri, &rv));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> file;
+  rv = fileURL->GetFile(getter_AddRefs(file));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  file.forget(aFile);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePicker::GetFileURL(nsIURI** aFileURL) {
+  *aFileURL = nullptr;
+  return NS_NewURI(aFileURL, mFileURL);
+}
+
+NS_IMETHODIMP
+nsFilePicker::GetFiles(nsISimpleEnumerator** aFiles) {
+  NS_ENSURE_ARG_POINTER(aFiles);
+
+  if (mMode == nsIFilePicker::modeOpenMultiple) {
+    return NS_NewArrayEnumerator(aFiles, mFiles, NS_GET_IID(nsIFile));
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+nsresult nsFilePicker::Show(nsIFilePicker::ResultCode* aReturn) {
+  NS_ENSURE_ARG_POINTER(aReturn);
+
+  nsresult rv = Open(nullptr);
+  if (NS_FAILED(rv)) return rv;
+
+  while (mFileChooser) {
+    g_main_context_iteration(nullptr, TRUE);
+  }
+
+  *aReturn = mResult;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePicker::Open(nsIFilePickerShownCallback* aCallback) {
+  // Can't show two dialogs concurrently with the same filepicker
+  if (mFileChooser) return NS_ERROR_NOT_AVAILABLE;
+
+  if (MaybeBlockFilePicker(aCallback)) {
+    return NS_OK;
+  }
+
+  NS_ConvertUTF16toUTF8 title(mTitle);
+
+  GtkWindow* parent_widget =
+      GTK_WINDOW(mParentWidget->GetNativeData(NS_NATIVE_SHELLWIDGET));
+
+  GtkFileChooserAction action = GetGtkFileChooserAction(mMode);
+
+  const gchar* accept_button;
+  NS_ConvertUTF16toUTF8 buttonLabel(mOkButtonLabel);
+  if (!mOkButtonLabel.IsEmpty()) {
+    accept_button = buttonLabel.get();
+  } else {
+    accept_button = nullptr;
+  }
+
+  void* file_chooser =
+      GtkFileChooserNew(title.get(), parent_widget, action, accept_button);
+
+  // If we have --enable-proxy-bypass-protection, then don't allow
+  // remote URLs to be used.
+#ifndef MOZ_PROXY_BYPASS_PROTECTION
+  if (mAllowURLs) {
+    gtk_file_chooser_set_local_only(GTK_FILE_CHOOSER(file_chooser), FALSE);
+  }
+#endif
+
+  if (action == GTK_FILE_CHOOSER_ACTION_OPEN ||
+      action == GTK_FILE_CHOOSER_ACTION_SAVE) {
+    GtkWidget* img_preview = gtk_image_new();
+    gtk_file_chooser_set_preview_widget(GTK_FILE_CHOOSER(file_chooser),
+                                        img_preview);
+    g_signal_connect(file_chooser, "update-preview",
+                     G_CALLBACK(UpdateFilePreviewWidget), img_preview);
+  }
+
+  GtkFileChooserSetModal(file_chooser, parent_widget, TRUE);
+
+  NS_ConvertUTF16toUTF8 defaultName(mDefault);
+  switch (mMode) {
+    case nsIFilePicker::modeOpenMultiple:
+      gtk_file_chooser_set_select_multiple(GTK_FILE_CHOOSER(file_chooser),
+                                           TRUE);
+      break;
+    case nsIFilePicker::modeSave:
+      gtk_file_chooser_set_current_name(GTK_FILE_CHOOSER(file_chooser),
+                                        defaultName.get());
+      break;
+
+    default:
+      /* no additional setup needed */
+      break;
+  }
+
+  nsCOMPtr<nsIFile> defaultPath;
+  if (mDisplayDirectory) {
+    mDisplayDirectory->Clone(getter_AddRefs(defaultPath));
+  } else if (mPrevDisplayDirectory) {
+    mPrevDisplayDirectory->Clone(getter_AddRefs(defaultPath));
+  }
+
+  if (defaultPath) {
+    if (!defaultName.IsEmpty() && mMode != nsIFilePicker::modeSave) {
+      // Try to select the intended file. Even if it doesn't exist, GTK still
+      // switches directories.
+      defaultPath->AppendNative(defaultName);
+      nsAutoCString path;
+      defaultPath->GetNativePath(path);
+      gtk_file_chooser_set_filename(GTK_FILE_CHOOSER(file_chooser), path.get());
+    } else {
+      nsAutoCString directory;
+      defaultPath->GetNativePath(directory);
+
+      // Workaround for problematic refcounting in GTK3 before 3.16.
+      // We need to keep a reference to the dialog's internal delegate.
+      // Otherwise, if our dialog gets destroyed, we'll lose the dialog's
+      // delegate by the time this gets processed in the event loop.
+      // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1166741
+      if (GTK_IS_DIALOG(file_chooser)) {
+        GtkDialog* dialog = GTK_DIALOG(file_chooser);
+        GtkContainer* area = GTK_CONTAINER(gtk_dialog_get_content_area(dialog));
+        gtk_container_forall(
+            area,
+            [](GtkWidget* widget, gpointer data) {
+              if (GTK_IS_FILE_CHOOSER_WIDGET(widget)) {
+                auto result = static_cast<GtkFileChooserWidget**>(data);
+                *result = GTK_FILE_CHOOSER_WIDGET(widget);
+              }
+            },
+            &mFileChooserDelegate);
+
+        if (mFileChooserDelegate != nullptr) {
+          g_object_ref(mFileChooserDelegate);
+        }
+      }
+      gtk_file_chooser_set_current_folder(GTK_FILE_CHOOSER(file_chooser),
+                                          directory.get());
+    }
+  }
+
+  if (GTK_IS_DIALOG(file_chooser)) {
+    gtk_dialog_set_default_response(GTK_DIALOG(file_chooser),
+                                    GTK_RESPONSE_ACCEPT);
+  }
+
+  int32_t count = mFilters.Length();
+  for (int32_t i = 0; i < count; ++i) {
+    // This is fun... the GTK file picker does not accept a list of filters
+    // so we need to split out each string, and add it manually.
+
+    char** patterns = g_strsplit(mFilters[i].get(), ";", -1);
+    if (!patterns) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    GtkFileFilter* filter = gtk_file_filter_new();
+    for (int j = 0; patterns[j] != nullptr; ++j) {
+      nsAutoCString caseInsensitiveFilter =
+          MakeCaseInsensitiveShellGlob(g_strstrip(patterns[j]));
+      gtk_file_filter_add_pattern(filter, caseInsensitiveFilter.get());
+    }
+
+    g_strfreev(patterns);
+
+    if (!mFilterNames[i].IsEmpty()) {
+      // If we have a name for our filter, let's use that.
+      const char* filter_name = mFilterNames[i].get();
+      gtk_file_filter_set_name(filter, filter_name);
+    } else {
+      // If we don't have a name, let's just use the filter pattern.
+      const char* filter_pattern = mFilters[i].get();
+      gtk_file_filter_set_name(filter, filter_pattern);
+    }
+
+    gtk_file_chooser_add_filter(GTK_FILE_CHOOSER(file_chooser), filter);
+
+    // Set the initially selected filter
+    if (mSelectedType == i) {
+      gtk_file_chooser_set_filter(GTK_FILE_CHOOSER(file_chooser), filter);
+    }
+  }
+
+  gtk_file_chooser_set_do_overwrite_confirmation(GTK_FILE_CHOOSER(file_chooser),
+                                                 TRUE);
+
+  mFileChooser = file_chooser;
+  mCallback = aCallback;
+  NS_ADDREF_THIS();
+  g_signal_connect(file_chooser, "response", G_CALLBACK(OnResponse), this);
+  GtkFileChooserShow(file_chooser);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePicker::Close() {
+  if (mFileChooser) {
+    // Call ourself as done.
+    Done(mFileChooser, GTK_RESPONSE_CLOSE);
+  }
+
+  return NS_OK;
+}
+
+/* static */
+void nsFilePicker::OnResponse(void* file_chooser, gint response_id,
+                              gpointer user_data) {
+  static_cast<nsFilePicker*>(user_data)->Done(file_chooser, response_id);
+}
+
+/* static */
+void nsFilePicker::OnDestroy(GtkWidget* file_chooser, gpointer user_data) {
+  static_cast<nsFilePicker*>(user_data)->Done(file_chooser,
+                                              GTK_RESPONSE_CANCEL);
+}
+
+bool nsFilePicker::WarnForNonReadableFile(void* file_chooser) {
+  nsCOMPtr<nsIFile> file;
+  GetFile(getter_AddRefs(file));
+  if (!file) {
+    return false;
+  }
+
+  bool isReadable = false;
+  file->IsReadable(&isReadable);
+  if (isReadable) {
+    return false;
+  }
+
+  nsCOMPtr<nsIStringBundleService> stringService =
+      mozilla::components::StringBundle::Service();
+  if (!stringService) {
+    return false;
+  }
+
+  nsCOMPtr<nsIStringBundle> filepickerBundle;
+  nsresult rv = stringService->CreateBundle(
+      "chrome://global/locale/filepicker.properties",
+      getter_AddRefs(filepickerBundle));
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  nsAutoString errorMessage;
+  rv = filepickerBundle->GetStringFromName("selectedFileNotReadableError",
+                                           errorMessage);
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  GtkDialogFlags flags = GTK_DIALOG_DESTROY_WITH_PARENT;
+  auto* cancel_dialog = gtk_message_dialog_new(
+      GTK_WINDOW(file_chooser), flags, GTK_MESSAGE_ERROR, GTK_BUTTONS_CLOSE,
+      "%s", NS_ConvertUTF16toUTF8(errorMessage).get());
+  gtk_dialog_run(GTK_DIALOG(cancel_dialog));
+  gtk_widget_destroy(cancel_dialog);
+
+  return true;
+}
+
+void nsFilePicker::Done(void* file_chooser, gint response) {
+  mFileChooser = nullptr;
+
+  nsIFilePicker::ResultCode result;
+  switch (response) {
+    case GTK_RESPONSE_OK:
+    case GTK_RESPONSE_ACCEPT:
+      ReadValuesFromFileChooser(file_chooser);
+      result = nsIFilePicker::returnOK;
+      if (mMode == nsIFilePicker::modeSave) {
+        nsCOMPtr<nsIFile> file;
+        GetFile(getter_AddRefs(file));
+        if (file) {
+          bool exists = false;
+          file->Exists(&exists);
+          if (exists) result = nsIFilePicker::returnReplace;
+        }
+      } else if (mMode == nsIFilePicker::modeOpen) {
+        if (WarnForNonReadableFile(file_chooser)) {
+          result = nsIFilePicker::returnCancel;
+        }
+      }
+      break;
+
+    case GTK_RESPONSE_CANCEL:
+    case GTK_RESPONSE_CLOSE:
+    case GTK_RESPONSE_DELETE_EVENT:
+      result = nsIFilePicker::returnCancel;
+      break;
+
+    default:
+      NS_WARNING("Unexpected response");
+      result = nsIFilePicker::returnCancel;
+      break;
+  }
+
+  // A "response" signal won't be sent again but "destroy" will be.
+  g_signal_handlers_disconnect_by_func(file_chooser, FuncToGpointer(OnDestroy),
+                                       this);
+
+  // When response_id is GTK_RESPONSE_DELETE_EVENT or when called from
+  // OnDestroy, the widget would be destroyed anyway but it is fine if
+  // gtk_widget_destroy is called more than once.  gtk_widget_destroy has
+  // requests that any remaining references be released, but the reference
+  // count will not be decremented again if GtkWindow's reference has already
+  // been released.
+  GtkFileChooserDestroy(file_chooser);
+
+  if (mFileChooserDelegate) {
+    // Properly deref our acquired reference. We call this after
+    // gtk_widget_destroy() to try and ensure that pending file info
+    // queries caused by updating the current folder have been cancelled.
+    // However, we do not know for certain when the callback will run after
+    // cancelled.
+    g_idle_add(
+        [](gpointer data) -> gboolean {
+          g_object_unref(data);
+          return G_SOURCE_REMOVE;
+        },
+        mFileChooserDelegate);
+    mFileChooserDelegate = nullptr;
+  }
+
+  if (mCallback) {
+    mCallback->Done(result);
+    mCallback = nullptr;
+  } else {
+    mResult = result;
+  }
+  NS_RELEASE_THIS();
+}
+
+// All below functions available as of GTK 3.20+
+void* nsFilePicker::GtkFileChooserNew(const gchar* title, GtkWindow* parent,
+                                      GtkFileChooserAction action,
+                                      const gchar* accept_label) {
+  static auto sGtkFileChooserNativeNewPtr =
+      (void* (*)(const gchar*, GtkWindow*, GtkFileChooserAction, const gchar*,
+                 const gchar*))dlsym(RTLD_DEFAULT,
+                                     "gtk_file_chooser_native_new");
+  if (mUseNativeFileChooser && sGtkFileChooserNativeNewPtr != nullptr) {
+    return (*sGtkFileChooserNativeNewPtr)(title, parent, action, accept_label,
+                                          nullptr);
+  }
+  if (accept_label == nullptr) {
+    accept_label = (action == GTK_FILE_CHOOSER_ACTION_SAVE) ? GTK_STOCK_SAVE
+                                                            : GTK_STOCK_OPEN;
+  }
+  GtkWidget* file_chooser = gtk_file_chooser_dialog_new(
+      title, parent, action, GTK_STOCK_CANCEL, GTK_RESPONSE_CANCEL,
+      accept_label, GTK_RESPONSE_ACCEPT, nullptr);
+  gtk_dialog_set_alternative_button_order(
+      GTK_DIALOG(file_chooser), GTK_RESPONSE_ACCEPT, GTK_RESPONSE_CANCEL, -1);
+  return file_chooser;
+}
+
+void nsFilePicker::GtkFileChooserShow(void* file_chooser) {
+  static auto sGtkNativeDialogShowPtr =
+      (void (*)(void*))dlsym(RTLD_DEFAULT, "gtk_native_dialog_show");
+  if (mUseNativeFileChooser && sGtkNativeDialogShowPtr != nullptr) {
+    const char* portalEnvString = g_getenv("GTK_USE_PORTAL");
+    bool setPortalEnv =
+        (portalEnvString && *portalEnvString == '0') || !portalEnvString;
+    if (setPortalEnv) {
+      setenv("GTK_USE_PORTAL", "1", true);
+    }
+    (*sGtkNativeDialogShowPtr)(file_chooser);
+    if (setPortalEnv) {
+      unsetenv("GTK_USE_PORTAL");
+    }
+  } else {
+    g_signal_connect(file_chooser, "destroy", G_CALLBACK(OnDestroy), this);
+    gtk_widget_show(GTK_WIDGET(file_chooser));
+  }
+}
+
+void nsFilePicker::GtkFileChooserDestroy(void* file_chooser) {
+  static auto sGtkNativeDialogDestroyPtr =
+      (void (*)(void*))dlsym(RTLD_DEFAULT, "gtk_native_dialog_destroy");
+  if (mUseNativeFileChooser && sGtkNativeDialogDestroyPtr != nullptr) {
+    (*sGtkNativeDialogDestroyPtr)(file_chooser);
+  } else {
+    gtk_widget_destroy(GTK_WIDGET(file_chooser));
+  }
+}
+
+void nsFilePicker::GtkFileChooserSetModal(void* file_chooser,
+                                          GtkWindow* parent_widget,
+                                          gboolean modal) {
+  static auto sGtkNativeDialogSetModalPtr = (void (*)(void*, gboolean))dlsym(
+      RTLD_DEFAULT, "gtk_native_dialog_set_modal");
+  if (mUseNativeFileChooser && sGtkNativeDialogSetModalPtr != nullptr) {
+    (*sGtkNativeDialogSetModalPtr)(file_chooser, modal);
+  } else {
+    GtkWindow* window = GTK_WINDOW(file_chooser);
+    gtk_window_set_modal(window, modal);
+    if (parent_widget != nullptr) {
+      gtk_window_set_destroy_with_parent(window, modal);
+    }
+  }
+}
+
+#undef LOG
diff --git a/widget/gtk/nsFilePicker.h b/widget/gtk/nsFilePicker.h
new file mode 100644
index 0000000000..f8fc22bc97
--- /dev/null
+++ b/widget/gtk/nsFilePicker.h
@@ -0,0 +1,96 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsFilePicker_h__
+#define nsFilePicker_h__
+
+#include <gtk/gtk.h>
+
+#include "nsBaseFilePicker.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "nsCOMArray.h"
+
+class nsIWidget;
+class nsIFile;
+
+class nsFilePicker : public nsBaseFilePicker {
+ public:
+  nsFilePicker();
+
+  NS_DECL_ISUPPORTS
+
+  // nsIFilePicker (less what's in nsBaseFilePicker)
+  NS_IMETHOD Open(nsIFilePickerShownCallback* aCallback) override;
+  NS_IMETHOD Close() override;
+  NS_IMETHOD IsModeSupported(nsIFilePicker::Mode, JSContext*,
+                             mozilla::dom::Promise**) override;
+  NS_IMETHOD AppendFilters(int32_t aFilterMask) override;
+  NS_IMETHOD AppendFilter(const nsAString& aTitle,
+                          const nsAString& aFilter) override;
+  NS_IMETHOD SetDefaultString(const nsAString& aString) override;
+  NS_IMETHOD GetDefaultString(nsAString& aString) override;
+  NS_IMETHOD SetDefaultExtension(const nsAString& aExtension) override;
+  NS_IMETHOD GetDefaultExtension(nsAString& aExtension) override;
+  NS_IMETHOD GetFilterIndex(int32_t* aFilterIndex) override;
+  NS_IMETHOD SetFilterIndex(int32_t aFilterIndex) override;
+  NS_IMETHOD GetFile(nsIFile** aFile) override;
+  NS_IMETHOD GetFileURL(nsIURI** aFileURL) override;
+  NS_IMETHOD GetFiles(nsISimpleEnumerator** aFiles) override;
+
+  // nsBaseFilePicker
+  virtual void InitNative(nsIWidget* aParent, const nsAString& aTitle) override;
+
+  static void Shutdown();
+
+ protected:
+  virtual ~nsFilePicker();
+
+  nsresult Show(nsIFilePicker::ResultCode* aReturn) override;
+  void ReadValuesFromFileChooser(void* file_chooser);
+
+  bool WarnForNonReadableFile(void* file_chooser);
+
+  static void OnResponse(void* file_chooser, gint response_id,
+                         gpointer user_data);
+  static void OnDestroy(GtkWidget* file_chooser, gpointer user_data);
+  void Done(void* file_chooser, gint response_id);
+
+  nsCOMPtr<nsIWidget> mParentWidget;
+  nsCOMPtr<nsIFilePickerShownCallback> mCallback;
+  nsCOMArray<nsIFile> mFiles;
+
+  int16_t mSelectedType;
+  nsIFilePicker::ResultCode mResult;
+  bool mAllowURLs;
+  nsCString mFileURL;
+  nsString mTitle;
+  nsString mDefault;
+  nsString mDefaultExtension;
+
+  nsTArray<nsCString> mFilters;
+  nsTArray<nsCString> mFilterNames;
+
+ private:
+  static nsIFile* mPrevDisplayDirectory;
+
+  void* GtkFileChooserNew(const gchar* title, GtkWindow* parent,
+                          GtkFileChooserAction action,
+                          const gchar* accept_label);
+  void GtkFileChooserShow(void* file_chooser);
+  void GtkFileChooserDestroy(void* file_chooser);
+  void GtkFileChooserSetModal(void* file_chooser, GtkWindow* parent_widget,
+                              gboolean modal);
+
+  GtkFileChooserWidget* mFileChooserDelegate;
+  bool mUseNativeFileChooser;
+
+  /**
+   * mFileChooser is non-null while open.
+   */
+  void* mFileChooser = nullptr;
+};
+
+#endif
diff --git a/widget/gtk/nsGTKToolkit.h b/widget/gtk/nsGTKToolkit.h
new file mode 100644
index 0000000000..5129ba419d
--- /dev/null
+++ b/widget/gtk/nsGTKToolkit.h
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GTKTOOLKIT_H
+#define GTKTOOLKIT_H
+
+#include "nsString.h"
+#include <gtk/gtk.h>
+
+/**
+ * Wrapper around the thread running the message pump.
+ * The toolkit abstraction is necessary because the message pump must
+ * execute within the same thread that created the widget under Win32.
+ */
+
+class nsGTKToolkit final {
+ public:
+  nsGTKToolkit() = default;
+
+  static nsGTKToolkit* GetToolkit();
+  static void Shutdown() {
+    delete gToolkit;
+    gToolkit = nullptr;
+  }
+
+  /**
+   * Get/set our startup token value. (XDG_ACTIVATION_TOKEN/DESKTOP_STARTUP_ID)
+   * When non-empty, this is applied to the next toplevel window to be shown or
+   * focused (and then immediately cleared).
+   */
+  void SetStartupToken(const nsACString& aToken) { mStartupToken = aToken; }
+  const nsCString& GetStartupToken() const { return mStartupToken; }
+
+  /**
+   * Get/set the timestamp value to be used, if non-zero, to focus the
+   * next top-level window to be shown or focused (upon which it is cleared).
+   */
+  void SetFocusTimestamp(uint32_t aTimestamp) { mFocusTimestamp = aTimestamp; }
+  uint32_t GetFocusTimestamp() const { return mFocusTimestamp; }
+
+ private:
+  static nsGTKToolkit* gToolkit;
+
+  nsCString mStartupToken;
+  uint32_t mFocusTimestamp = 0;
+};
+
+#endif  // GTKTOOLKIT_H
diff --git a/widget/gtk/nsGtkCursors.h b/widget/gtk/nsGtkCursors.h
new file mode 100644
index 0000000000..f30ed593a9
--- /dev/null
+++ b/widget/gtk/nsGtkCursors.h
@@ -0,0 +1,416 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsGtkCursors_h__
+#define nsGtkCursors_h__
+
+typedef struct {
+  const unsigned char* bits;
+  const unsigned char* mask_bits;
+  int hot_x;
+  int hot_y;
+  const char* hash;
+} nsGtkCursor;
+
+/* MOZ_CURSOR_HAND_GRAB */
+static const unsigned char moz_hand_grab_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x00,
+    0x60, 0x39, 0x00, 0x00, 0x90, 0x49, 0x00, 0x00, 0x90, 0x49, 0x01, 0x00,
+    0x20, 0xc9, 0x02, 0x00, 0x20, 0x49, 0x02, 0x00, 0x58, 0x40, 0x02, 0x00,
+    0x64, 0x00, 0x02, 0x00, 0x44, 0x00, 0x01, 0x00, 0x08, 0x00, 0x01, 0x00,
+    0x10, 0x00, 0x01, 0x00, 0x10, 0x80, 0x00, 0x00, 0x20, 0x80, 0x00, 0x00,
+    0x40, 0x40, 0x00, 0x00, 0x80, 0x40, 0x00, 0x00, 0x80, 0x40, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_hand_grab_mask_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x00, 0x60, 0x3f, 0x00, 0x00,
+    0xf0, 0x7f, 0x00, 0x00, 0xf8, 0xff, 0x01, 0x00, 0xf8, 0xff, 0x03, 0x00,
+    0xf0, 0xff, 0x07, 0x00, 0xf8, 0xff, 0x07, 0x00, 0xfc, 0xff, 0x07, 0x00,
+    0xfe, 0xff, 0x07, 0x00, 0xfe, 0xff, 0x03, 0x00, 0xfc, 0xff, 0x03, 0x00,
+    0xf8, 0xff, 0x03, 0x00, 0xf8, 0xff, 0x01, 0x00, 0xf0, 0xff, 0x01, 0x00,
+    0xe0, 0xff, 0x00, 0x00, 0xc0, 0xff, 0x00, 0x00, 0xc0, 0xff, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_HAND_GRABBING */
+static const unsigned char moz_hand_grabbing_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0xc0, 0x36, 0x00, 0x00, 0x20, 0xc9, 0x00, 0x00, 0x20, 0x40, 0x01, 0x00,
+    0x40, 0x00, 0x01, 0x00, 0x60, 0x00, 0x01, 0x00, 0x10, 0x00, 0x01, 0x00,
+    0x10, 0x00, 0x01, 0x00, 0x10, 0x80, 0x00, 0x00, 0x20, 0x80, 0x00, 0x00,
+    0x40, 0x40, 0x00, 0x00, 0x80, 0x40, 0x00, 0x00, 0x80, 0x40, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_hand_grabbing_mask_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc0, 0x36, 0x00, 0x00,
+    0xe0, 0xff, 0x00, 0x00, 0xf0, 0xff, 0x01, 0x00, 0xf0, 0xff, 0x03, 0x00,
+    0xe0, 0xff, 0x03, 0x00, 0xf0, 0xff, 0x03, 0x00, 0xf8, 0xff, 0x03, 0x00,
+    0xf8, 0xff, 0x03, 0x00, 0xf8, 0xff, 0x01, 0x00, 0xf0, 0xff, 0x01, 0x00,
+    0xe0, 0xff, 0x00, 0x00, 0xc0, 0xff, 0x00, 0x00, 0xc0, 0x7f, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_COPY */
+static const unsigned char moz_copy_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00,
+    0x0c, 0x00, 0x00, 0x00, 0x1c, 0x00, 0x00, 0x00, 0x3c, 0x00, 0x00, 0x00,
+    0x7c, 0x00, 0x00, 0x00, 0xfc, 0x00, 0x00, 0x00, 0xfc, 0x01, 0x00, 0x00,
+    0xfc, 0x03, 0x00, 0x00, 0x7c, 0x30, 0x00, 0x00, 0x6c, 0x30, 0x00, 0x00,
+    0xc4, 0xfc, 0x00, 0x00, 0xc0, 0xfc, 0x00, 0x00, 0x80, 0x31, 0x00, 0x00,
+    0x80, 0x31, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_copy_mask_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x00, 0x00, 0x0e, 0x00, 0x00, 0x00,
+    0x1e, 0x00, 0x00, 0x00, 0x3e, 0x00, 0x00, 0x00, 0x7e, 0x00, 0x00, 0x00,
+    0xfe, 0x00, 0x00, 0x00, 0xfe, 0x01, 0x00, 0x00, 0xfe, 0x03, 0x00, 0x00,
+    0xfe, 0x37, 0x00, 0x00, 0xfe, 0x7b, 0x00, 0x00, 0xfe, 0xfc, 0x00, 0x00,
+    0xee, 0xff, 0x01, 0x00, 0xe4, 0xff, 0x01, 0x00, 0xc0, 0xff, 0x00, 0x00,
+    0xc0, 0x7b, 0x00, 0x00, 0x80, 0x31, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_ALIAS */
+static const unsigned char moz_alias_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00,
+    0x0c, 0x00, 0x00, 0x00, 0x1c, 0x00, 0x00, 0x00, 0x3c, 0x00, 0x00, 0x00,
+    0x7c, 0x00, 0x00, 0x00, 0xfc, 0x00, 0x00, 0x00, 0xfc, 0x01, 0x00, 0x00,
+    0xfc, 0x03, 0x00, 0x00, 0x7c, 0xf0, 0x00, 0x00, 0x6c, 0xe0, 0x00, 0x00,
+    0xc4, 0xf0, 0x00, 0x00, 0xc0, 0xb0, 0x00, 0x00, 0x80, 0x19, 0x00, 0x00,
+    0x80, 0x19, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_alias_mask_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x00, 0x00, 0x0e, 0x00, 0x00, 0x00,
+    0x1e, 0x00, 0x00, 0x00, 0x3e, 0x00, 0x00, 0x00, 0x7e, 0x00, 0x00, 0x00,
+    0xfe, 0x00, 0x00, 0x00, 0xfe, 0x01, 0x00, 0x00, 0xfe, 0x03, 0x00, 0x00,
+    0xfe, 0xf7, 0x00, 0x00, 0xfe, 0xfb, 0x01, 0x00, 0xfe, 0xf0, 0x01, 0x00,
+    0xee, 0xf9, 0x01, 0x00, 0xe4, 0xf9, 0x01, 0x00, 0xc0, 0xbf, 0x00, 0x00,
+    0xc0, 0x3f, 0x00, 0x00, 0x80, 0x19, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_CONTEXT_MENU */
+static const unsigned char moz_menu_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00,
+    0x0c, 0x00, 0x00, 0x00, 0x1c, 0x00, 0x00, 0x00, 0x3c, 0x00, 0x00, 0x00,
+    0x7c, 0x00, 0x00, 0x00, 0xfc, 0x00, 0x00, 0x00, 0xfc, 0xfd, 0x00, 0x00,
+    0xfc, 0xff, 0x00, 0x00, 0x7c, 0x84, 0x00, 0x00, 0x6c, 0xfc, 0x00, 0x00,
+    0xc4, 0x84, 0x00, 0x00, 0xc0, 0xfc, 0x00, 0x00, 0x80, 0x85, 0x00, 0x00,
+    0x80, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_menu_mask_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x00, 0x00, 0x0e, 0x00, 0x00, 0x00,
+    0x1e, 0x00, 0x00, 0x00, 0x3e, 0x00, 0x00, 0x00, 0x7e, 0x00, 0x00, 0x00,
+    0xfe, 0x00, 0x00, 0x00, 0xfe, 0xfd, 0x00, 0x00, 0xfe, 0xff, 0x01, 0x00,
+    0xfe, 0xff, 0x01, 0x00, 0xfe, 0xff, 0x01, 0x00, 0xfe, 0xfe, 0x01, 0x00,
+    0xee, 0xff, 0x01, 0x00, 0xe4, 0xff, 0x01, 0x00, 0xc0, 0xff, 0x01, 0x00,
+    0xc0, 0xff, 0x01, 0x00, 0x80, 0xfd, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_SPINNING */
+static const unsigned char moz_spinning_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00,
+    0x0c, 0x00, 0x00, 0x00, 0x1c, 0x00, 0x00, 0x00, 0x3c, 0x00, 0x00, 0x00,
+    0x7c, 0x00, 0x00, 0x00, 0xfc, 0x00, 0x00, 0x00, 0xfc, 0x01, 0x00, 0x00,
+    0xfc, 0x3b, 0x00, 0x00, 0x7c, 0x38, 0x00, 0x00, 0x6c, 0x54, 0x00, 0x00,
+    0xc4, 0xdc, 0x00, 0x00, 0xc0, 0x44, 0x00, 0x00, 0x80, 0x39, 0x00, 0x00,
+    0x80, 0x39, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_spinning_mask_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x06, 0x00, 0x00, 0x00, 0x0e, 0x00, 0x00, 0x00,
+    0x1e, 0x00, 0x00, 0x00, 0x3e, 0x00, 0x00, 0x00, 0x7e, 0x00, 0x00, 0x00,
+    0xfe, 0x00, 0x00, 0x00, 0xfe, 0x01, 0x00, 0x00, 0xfe, 0x3b, 0x00, 0x00,
+    0xfe, 0x7f, 0x00, 0x00, 0xfe, 0x7f, 0x00, 0x00, 0xfe, 0xfe, 0x00, 0x00,
+    0xee, 0xff, 0x01, 0x00, 0xe4, 0xff, 0x00, 0x00, 0xc0, 0x7f, 0x00, 0x00,
+    0xc0, 0x7f, 0x00, 0x00, 0x80, 0x39, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_ZOOM_IN */
+static const unsigned char moz_zoom_in_bits[] = {
+    0xf0, 0x00, 0x00, 0x00, 0x0c, 0x03, 0x00, 0x00, 0x02, 0x04, 0x00, 0x00,
+    0x62, 0x04, 0x00, 0x00, 0x61, 0x08, 0x00, 0x00, 0xf9, 0x09, 0x00, 0x00,
+    0xf9, 0x09, 0x00, 0x00, 0x61, 0x08, 0x00, 0x00, 0x62, 0x04, 0x00, 0x00,
+    0x02, 0x04, 0x00, 0x00, 0x0c, 0x0f, 0x00, 0x00, 0xf0, 0x1c, 0x00, 0x00,
+    0x00, 0x38, 0x00, 0x00, 0x00, 0x70, 0x00, 0x00, 0x00, 0xe0, 0x00, 0x00,
+    0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_zoom_in_mask_bits[] = {
+    0xf0, 0x00, 0x00, 0x00, 0xfc, 0x03, 0x00, 0x00, 0xfe, 0x07, 0x00, 0x00,
+    0xfe, 0x07, 0x00, 0x00, 0xff, 0x0f, 0x00, 0x00, 0xff, 0x0f, 0x00, 0x00,
+    0xff, 0x0f, 0x00, 0x00, 0xff, 0x0f, 0x00, 0x00, 0xfe, 0x07, 0x00, 0x00,
+    0xfe, 0x07, 0x00, 0x00, 0xfc, 0x0f, 0x00, 0x00, 0xf0, 0x1c, 0x00, 0x00,
+    0x00, 0x38, 0x00, 0x00, 0x00, 0x70, 0x00, 0x00, 0x00, 0xe0, 0x00, 0x00,
+    0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_ZOOM_OUT */
+static const unsigned char moz_zoom_out_bits[] = {
+    0xf0, 0x00, 0x00, 0x00, 0x0c, 0x03, 0x00, 0x00, 0x02, 0x04, 0x00, 0x00,
+    0x02, 0x04, 0x00, 0x00, 0x01, 0x08, 0x00, 0x00, 0xf9, 0x09, 0x00, 0x00,
+    0xf9, 0x09, 0x00, 0x00, 0x01, 0x08, 0x00, 0x00, 0x02, 0x04, 0x00, 0x00,
+    0x02, 0x04, 0x00, 0x00, 0x0c, 0x0f, 0x00, 0x00, 0xf0, 0x1c, 0x00, 0x00,
+    0x00, 0x38, 0x00, 0x00, 0x00, 0x70, 0x00, 0x00, 0x00, 0xe0, 0x00, 0x00,
+    0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_zoom_out_mask_bits[] = {
+    0xf0, 0x00, 0x00, 0x00, 0xfc, 0x03, 0x00, 0x00, 0xfe, 0x07, 0x00, 0x00,
+    0xfe, 0x07, 0x00, 0x00, 0xff, 0x0f, 0x00, 0x00, 0xff, 0x0f, 0x00, 0x00,
+    0xff, 0x0f, 0x00, 0x00, 0xff, 0x0f, 0x00, 0x00, 0xfe, 0x07, 0x00, 0x00,
+    0xfe, 0x07, 0x00, 0x00, 0xfc, 0x0f, 0x00, 0x00, 0xf0, 0x1c, 0x00, 0x00,
+    0x00, 0x38, 0x00, 0x00, 0x00, 0x70, 0x00, 0x00, 0x00, 0xe0, 0x00, 0x00,
+    0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_NOT_ALLOWED */
+static const unsigned char moz_not_allowed_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x80, 0x1f, 0x00, 0x00, 0xe0, 0x7f, 0x00, 0x00,
+    0xf0, 0xf0, 0x00, 0x00, 0x38, 0xc0, 0x01, 0x00, 0x7c, 0x80, 0x03, 0x00,
+    0xec, 0x00, 0x03, 0x00, 0xce, 0x01, 0x07, 0x00, 0x86, 0x03, 0x06, 0x00,
+    0x06, 0x07, 0x06, 0x00, 0x06, 0x0e, 0x06, 0x00, 0x06, 0x1c, 0x06, 0x00,
+    0x0e, 0x38, 0x07, 0x00, 0x0c, 0x70, 0x03, 0x00, 0x1c, 0xe0, 0x03, 0x00,
+    0x38, 0xc0, 0x01, 0x00, 0xf0, 0xf0, 0x00, 0x00, 0xe0, 0x7f, 0x00, 0x00,
+    0x80, 0x1f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_not_allowed_mask_bits[] = {
+    0x80, 0x1f, 0x00, 0x00, 0xe0, 0x7f, 0x00, 0x00, 0xf0, 0xff, 0x00, 0x00,
+    0xf8, 0xff, 0x01, 0x00, 0xfc, 0xf0, 0x03, 0x00, 0xfe, 0xc0, 0x07, 0x00,
+    0xfe, 0x81, 0x07, 0x00, 0xff, 0x83, 0x0f, 0x00, 0xcf, 0x07, 0x0f, 0x00,
+    0x8f, 0x0f, 0x0f, 0x00, 0x0f, 0x1f, 0x0f, 0x00, 0x0f, 0x3e, 0x0f, 0x00,
+    0x1f, 0xfc, 0x0f, 0x00, 0x1e, 0xf8, 0x07, 0x00, 0x3e, 0xf0, 0x07, 0x00,
+    0xfc, 0xf0, 0x03, 0x00, 0xf8, 0xff, 0x01, 0x00, 0xf0, 0xff, 0x00, 0x00,
+    0xe0, 0x7f, 0x00, 0x00, 0x80, 0x1f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_VERTICAL_TEXT */
+static const unsigned char moz_vertical_text_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x02, 0x40, 0x00, 0x00, 0x02, 0x40, 0x00, 0x00,
+    0x06, 0x60, 0x00, 0x00, 0xfc, 0x3f, 0x00, 0x00, 0x06, 0x60, 0x00, 0x00,
+    0x02, 0x40, 0x00, 0x00, 0x02, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_vertical_text_mask_bits[] = {
+    0x07, 0xe0, 0x00, 0x00, 0x07, 0xe0, 0x00, 0x00, 0x0f, 0xf0, 0x00, 0x00,
+    0xff, 0xff, 0x00, 0x00, 0xfe, 0x7f, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00,
+    0x0f, 0xf0, 0x00, 0x00, 0x07, 0xe0, 0x00, 0x00, 0x07, 0xe0, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_NESW_RESIZE */
+static const unsigned char moz_nesw_resize_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0xc0, 0xff, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00,
+    0x00, 0xbe, 0x00, 0x00, 0x00, 0xbc, 0x00, 0x00, 0x00, 0xb8, 0x00, 0x00,
+    0x02, 0xb4, 0x00, 0x00, 0x02, 0xa2, 0x00, 0x00, 0x02, 0x81, 0x00, 0x00,
+    0x8a, 0x80, 0x00, 0x00, 0x5a, 0x80, 0x00, 0x00, 0x3a, 0x00, 0x00, 0x00,
+    0x7a, 0x00, 0x00, 0x00, 0xfa, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00,
+    0xfe, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_nesw_resize_mask_bits[] = {
+    0xc0, 0xff, 0x01, 0x00, 0xc0, 0xff, 0x01, 0x00, 0xc0, 0xff, 0x01, 0x00,
+    0x00, 0xff, 0x01, 0x00, 0x00, 0xfe, 0x01, 0x00, 0x00, 0xfc, 0x01, 0x00,
+    0x07, 0xfe, 0x01, 0x00, 0x07, 0xf7, 0x01, 0x00, 0x8f, 0xe3, 0x01, 0x00,
+    0xdf, 0xc1, 0x01, 0x00, 0xff, 0xc0, 0x01, 0x00, 0x7f, 0x00, 0x00, 0x00,
+    0xff, 0x00, 0x00, 0x00, 0xff, 0x01, 0x00, 0x00, 0xff, 0x07, 0x00, 0x00,
+    0xff, 0x07, 0x00, 0x00, 0xff, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_NWSE_RESIZE */
+static const unsigned char moz_nwse_resize_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0xfe, 0x07, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00,
+    0xfa, 0x00, 0x00, 0x00, 0x7a, 0x00, 0x00, 0x00, 0x3a, 0x00, 0x00, 0x00,
+    0x5a, 0x80, 0x00, 0x00, 0x8a, 0x80, 0x00, 0x00, 0x02, 0x81, 0x00, 0x00,
+    0x02, 0xa2, 0x00, 0x00, 0x02, 0xb4, 0x00, 0x00, 0x00, 0xb8, 0x00, 0x00,
+    0x00, 0xbc, 0x00, 0x00, 0x00, 0xbe, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00,
+    0xc0, 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_nwse_resize_mask_bits[] = {
+    0xff, 0x07, 0x00, 0x00, 0xff, 0x07, 0x00, 0x00, 0xff, 0x07, 0x00, 0x00,
+    0xff, 0x01, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0x7f, 0x00, 0x00, 0x00,
+    0xff, 0xc0, 0x01, 0x00, 0xdf, 0xc1, 0x01, 0x00, 0x8f, 0xe3, 0x01, 0x00,
+    0x07, 0xf7, 0x01, 0x00, 0x07, 0xfe, 0x01, 0x00, 0x00, 0xfc, 0x01, 0x00,
+    0x00, 0xfe, 0x01, 0x00, 0x00, 0xff, 0x01, 0x00, 0xc0, 0xff, 0x01, 0x00,
+    0xc0, 0xff, 0x01, 0x00, 0xc0, 0xff, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+/* MOZ_CURSOR_NONE */
+static const unsigned char moz_none_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+static const unsigned char moz_none_mask_bits[] = {
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+
+enum {
+  MOZ_CURSOR_HAND_GRAB,
+  MOZ_CURSOR_HAND_GRABBING,
+  MOZ_CURSOR_COPY,
+  MOZ_CURSOR_ALIAS,
+  MOZ_CURSOR_CONTEXT_MENU,
+  MOZ_CURSOR_SPINNING,
+  MOZ_CURSOR_ZOOM_IN,
+  MOZ_CURSOR_ZOOM_OUT,
+  MOZ_CURSOR_NOT_ALLOWED,
+  MOZ_CURSOR_VERTICAL_TEXT,
+  MOZ_CURSOR_NESW_RESIZE,
+  MOZ_CURSOR_NWSE_RESIZE,
+  MOZ_CURSOR_NONE
+};
+
+// create custom pixmap cursor. The hash values must stay in sync with the
+// bitmap data above. To see the hash function, have a look at XcursorImageHash
+// in libXcursor
+static const nsGtkCursor GtkCursors[] = {
+    {moz_hand_grab_bits, moz_hand_grab_mask_bits, 10, 10,
+     "5aca4d189052212118709018842178c0"},
+    {moz_hand_grabbing_bits, moz_hand_grabbing_mask_bits, 10, 10,
+     "208530c400c041818281048008011002"},
+    {moz_copy_bits, moz_copy_mask_bits, 2, 2,
+     "08ffe1cb5fe6fc01f906f1c063814ccf"},
+    {moz_alias_bits, moz_alias_mask_bits, 2, 2,
+     "0876e1c15ff2fc01f906f1c363074c0f"},
+    {moz_menu_bits, moz_menu_mask_bits, 2, 2,
+     "08ffe1e65f80fcfdf9fff11263e74c48"},
+    {moz_spinning_bits, moz_spinning_mask_bits, 2, 2,
+     "08e8e1c95fe2fc01f976f1e063a24ccd"},
+    {moz_zoom_in_bits, moz_zoom_in_mask_bits, 6, 6,
+     "f41c0e382c94c0958e07017e42b00462"},
+    {moz_zoom_out_bits, moz_zoom_out_mask_bits, 6, 6,
+     "f41c0e382c97c0938e07017e42800402"},
+    {moz_not_allowed_bits, moz_not_allowed_mask_bits, 9, 9,
+     "03b6e0fcb3499374a867d041f52298f0"},
+    {moz_vertical_text_bits, moz_vertical_text_mask_bits, 8, 4,
+     "048008013003cff3c00c801001200000"},
+    {moz_nesw_resize_bits, moz_nesw_resize_mask_bits, 8, 8,
+     "50585d75b494802d0151028115016902"},
+    {moz_nwse_resize_bits, moz_nwse_resize_mask_bits, 8, 8,
+     "38c5dff7c7b8962045400281044508d2"},
+    {moz_none_bits, moz_none_mask_bits, 0, 0, nullptr}};
+
+#endif /* nsGtkCursors_h__ */
diff --git a/widget/gtk/nsGtkKeyUtils.cpp b/widget/gtk/nsGtkKeyUtils.cpp
new file mode 100644
index 0000000000..7157a09664
--- /dev/null
+++ b/widget/gtk/nsGtkKeyUtils.cpp
@@ -0,0 +1,2541 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Logging.h"
+
+#include "nsGtkKeyUtils.h"
+
+#include <gdk/gdkkeysyms.h>
+#include <algorithm>
+#include <gdk/gdk.h>
+#include <dlfcn.h>
+#include <gdk/gdkkeysyms-compat.h>
+#ifdef MOZ_X11
+#  include <gdk/gdkx.h>
+#  include <X11/XKBlib.h>
+#  include "X11UndefineNone.h"
+#endif
+#include "IMContextWrapper.h"
+#include "WidgetUtils.h"
+#include "WidgetUtilsGtk.h"
+#include "x11/keysym2ucs.h"
+#include "nsContentUtils.h"
+#include "nsGtkUtils.h"
+#include "nsIBidiKeyboard.h"
+#include "nsPrintfCString.h"
+#include "nsReadableUtils.h"
+#include "nsServiceManagerUtils.h"
+#include "nsWindow.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEvents.h"
+
+#ifdef MOZ_WAYLAND
+#  include <sys/mman.h>
+#  include "nsWaylandDisplay.h"
+#endif
+
+// For collecting other people's log, tell them `MOZ_LOG=KeyboardHandler:4,sync`
+// rather than `MOZ_LOG=KeyboardHandler:5,sync` since using `5` may create too
+// big file.
+// Therefore you shouldn't use `LogLevel::Verbose` for logging usual behavior.
+mozilla::LazyLogModule gKeyLog("KeyboardHandler");
+
+namespace mozilla {
+namespace widget {
+
+#define IS_ASCII_ALPHABETICAL(key) \
+  ((('a' <= key) && (key <= 'z')) || (('A' <= key) && (key <= 'Z')))
+
+#define MOZ_MODIFIER_KEYS "MozKeymapWrapper"
+
+KeymapWrapper* KeymapWrapper::sInstance = nullptr;
+guint KeymapWrapper::sLastRepeatableHardwareKeyCode = 0;
+#ifdef MOZ_X11
+Time KeymapWrapper::sLastRepeatableKeyTime = 0;
+#endif
+KeymapWrapper::RepeatState KeymapWrapper::sRepeatState =
+    KeymapWrapper::NOT_PRESSED;
+
+#ifdef MOZ_WAYLAND
+wl_seat* KeymapWrapper::sSeat = nullptr;
+int KeymapWrapper::sSeatID = -1;
+wl_keyboard* KeymapWrapper::sKeyboard = nullptr;
+#endif
+
+static const char* GetBoolName(bool aBool) { return aBool ? "TRUE" : "FALSE"; }
+
+static const char* GetStatusName(nsEventStatus aStatus) {
+  switch (aStatus) {
+    case nsEventStatus_eConsumeDoDefault:
+      return "nsEventStatus_eConsumeDoDefault";
+    case nsEventStatus_eConsumeNoDefault:
+      return "nsEventStatus_eConsumeNoDefault";
+    case nsEventStatus_eIgnore:
+      return "nsEventStatus_eIgnore";
+    case nsEventStatus_eSentinel:
+      return "nsEventStatus_eSentinel";
+    default:
+      return "Illegal value";
+  }
+}
+
+static const nsCString GetKeyLocationName(uint32_t aLocation) {
+  switch (aLocation) {
+    case eKeyLocationLeft:
+      return "KEY_LOCATION_LEFT"_ns;
+    case eKeyLocationRight:
+      return "KEY_LOCATION_RIGHT"_ns;
+    case eKeyLocationStandard:
+      return "KEY_LOCATION_STANDARD"_ns;
+    case eKeyLocationNumpad:
+      return "KEY_LOCATION_NUMPAD"_ns;
+    default:
+      return nsPrintfCString("Unknown (0x%04X)", aLocation);
+  }
+}
+
+static const nsCString GetCharacterCodeName(char16_t aChar) {
+  switch (aChar) {
+    case 0x0000:
+      return "NULL (0x0000)"_ns;
+    case 0x0008:
+      return "BACKSPACE (0x0008)"_ns;
+    case 0x0009:
+      return "CHARACTER TABULATION (0x0009)"_ns;
+    case 0x000A:
+      return "LINE FEED (0x000A)"_ns;
+    case 0x000B:
+      return "LINE TABULATION (0x000B)"_ns;
+    case 0x000C:
+      return "FORM FEED (0x000C)"_ns;
+    case 0x000D:
+      return "CARRIAGE RETURN (0x000D)"_ns;
+    case 0x0018:
+      return "CANCEL (0x0018)"_ns;
+    case 0x001B:
+      return "ESCAPE (0x001B)"_ns;
+    case 0x0020:
+      return "SPACE (0x0020)"_ns;
+    case 0x007F:
+      return "DELETE (0x007F)"_ns;
+    case 0x00A0:
+      return "NO-BREAK SPACE (0x00A0)"_ns;
+    case 0x00AD:
+      return "SOFT HYPHEN (0x00AD)"_ns;
+    case 0x2000:
+      return "EN QUAD (0x2000)"_ns;
+    case 0x2001:
+      return "EM QUAD (0x2001)"_ns;
+    case 0x2002:
+      return "EN SPACE (0x2002)"_ns;
+    case 0x2003:
+      return "EM SPACE (0x2003)"_ns;
+    case 0x2004:
+      return "THREE-PER-EM SPACE (0x2004)"_ns;
+    case 0x2005:
+      return "FOUR-PER-EM SPACE (0x2005)"_ns;
+    case 0x2006:
+      return "SIX-PER-EM SPACE (0x2006)"_ns;
+    case 0x2007:
+      return "FIGURE SPACE (0x2007)"_ns;
+    case 0x2008:
+      return "PUNCTUATION SPACE (0x2008)"_ns;
+    case 0x2009:
+      return "THIN SPACE (0x2009)"_ns;
+    case 0x200A:
+      return "HAIR SPACE (0x200A)"_ns;
+    case 0x200B:
+      return "ZERO WIDTH SPACE (0x200B)"_ns;
+    case 0x200C:
+      return "ZERO WIDTH NON-JOINER (0x200C)"_ns;
+    case 0x200D:
+      return "ZERO WIDTH JOINER (0x200D)"_ns;
+    case 0x200E:
+      return "LEFT-TO-RIGHT MARK (0x200E)"_ns;
+    case 0x200F:
+      return "RIGHT-TO-LEFT MARK (0x200F)"_ns;
+    case 0x2029:
+      return "PARAGRAPH SEPARATOR (0x2029)"_ns;
+    case 0x202A:
+      return "LEFT-TO-RIGHT EMBEDDING (0x202A)"_ns;
+    case 0x202B:
+      return "RIGHT-TO-LEFT EMBEDDING (0x202B)"_ns;
+    case 0x202D:
+      return "LEFT-TO-RIGHT OVERRIDE (0x202D)"_ns;
+    case 0x202E:
+      return "RIGHT-TO-LEFT OVERRIDE (0x202E)"_ns;
+    case 0x202F:
+      return "NARROW NO-BREAK SPACE (0x202F)"_ns;
+    case 0x205F:
+      return "MEDIUM MATHEMATICAL SPACE (0x205F)"_ns;
+    case 0x2060:
+      return "WORD JOINER (0x2060)"_ns;
+    case 0x2066:
+      return "LEFT-TO-RIGHT ISOLATE (0x2066)"_ns;
+    case 0x2067:
+      return "RIGHT-TO-LEFT ISOLATE (0x2067)"_ns;
+    case 0x3000:
+      return "IDEOGRAPHIC SPACE (0x3000)"_ns;
+    case 0xFEFF:
+      return "ZERO WIDTH NO-BREAK SPACE (0xFEFF)"_ns;
+    default: {
+      if (aChar < ' ' || (aChar >= 0x80 && aChar < 0xA0)) {
+        return nsPrintfCString("control (0x%04X)", aChar);
+      }
+      if (NS_IS_HIGH_SURROGATE(aChar)) {
+        return nsPrintfCString("high surrogate (0x%04X)", aChar);
+      }
+      if (NS_IS_LOW_SURROGATE(aChar)) {
+        return nsPrintfCString("low surrogate (0x%04X)", aChar);
+      }
+      return nsPrintfCString("'%s' (0x%04X)",
+                             NS_ConvertUTF16toUTF8(nsAutoString(aChar)).get(),
+                             aChar);
+    }
+  }
+}
+
+static const nsCString GetCharacterCodeNames(const char16_t* aChars,
+                                             uint32_t aLength) {
+  if (!aLength) {
+    return "\"\""_ns;
+  }
+  nsCString result;
+  result.AssignLiteral("\"");
+  StringJoinAppend(result, ", "_ns, Span{aChars, aLength},
+                   [](nsACString& dest, const char16_t charValue) {
+                     dest.Append(GetCharacterCodeName(charValue));
+                   });
+  result.AppendLiteral("\"");
+  return result;
+}
+
+static const nsCString GetCharacterCodeNames(const nsAString& aString) {
+  return GetCharacterCodeNames(aString.BeginReading(), aString.Length());
+}
+
+/* static */
+const char* KeymapWrapper::GetModifierName(MappedModifier aModifier) {
+  switch (aModifier) {
+    case CAPS_LOCK:
+      return "CapsLock";
+    case NUM_LOCK:
+      return "NumLock";
+    case SCROLL_LOCK:
+      return "ScrollLock";
+    case SHIFT:
+      return "Shift";
+    case CTRL:
+      return "Ctrl";
+    case ALT:
+      return "Alt";
+    case SUPER:
+      return "Super";
+    case HYPER:
+      return "Hyper";
+    case META:
+      return "Meta";
+    case LEVEL3:
+      return "Level3";
+    case LEVEL5:
+      return "Level5";
+    case NOT_MODIFIER:
+      return "NotModifier";
+    default:
+      return "InvalidValue";
+  }
+}
+
+/* static */
+KeymapWrapper::MappedModifier KeymapWrapper::GetModifierForGDKKeyval(
+    guint aGdkKeyval) {
+  switch (aGdkKeyval) {
+    case GDK_Caps_Lock:
+      return CAPS_LOCK;
+    case GDK_Num_Lock:
+      return NUM_LOCK;
+    case GDK_Scroll_Lock:
+      return SCROLL_LOCK;
+    case GDK_Shift_Lock:
+    case GDK_Shift_L:
+    case GDK_Shift_R:
+      return SHIFT;
+    case GDK_Control_L:
+    case GDK_Control_R:
+      return CTRL;
+    case GDK_Alt_L:
+    case GDK_Alt_R:
+      return ALT;
+    case GDK_Super_L:
+    case GDK_Super_R:
+      return SUPER;
+    case GDK_Hyper_L:
+    case GDK_Hyper_R:
+      return HYPER;
+    case GDK_Meta_L:
+    case GDK_Meta_R:
+      return META;
+    case GDK_ISO_Level3_Shift:
+    case GDK_Mode_switch:
+      return LEVEL3;
+    case GDK_ISO_Level5_Shift:
+      return LEVEL5;
+    default:
+      return NOT_MODIFIER;
+  }
+}
+
+guint KeymapWrapper::GetGdkModifierMask(MappedModifier aModifier) const {
+  switch (aModifier) {
+    case CAPS_LOCK:
+      return GDK_LOCK_MASK;
+    case NUM_LOCK:
+      return mModifierMasks[INDEX_NUM_LOCK];
+    case SCROLL_LOCK:
+      return mModifierMasks[INDEX_SCROLL_LOCK];
+    case SHIFT:
+      return GDK_SHIFT_MASK;
+    case CTRL:
+      return GDK_CONTROL_MASK;
+    case ALT:
+      return mModifierMasks[INDEX_ALT];
+    case SUPER:
+      return GDK_SUPER_MASK;
+    case HYPER:
+      return mModifierMasks[INDEX_HYPER];
+    case META:
+      return mModifierMasks[INDEX_META];
+    case LEVEL3:
+      return mModifierMasks[INDEX_LEVEL3];
+    case LEVEL5:
+      return mModifierMasks[INDEX_LEVEL5];
+    default:
+      return 0;
+  }
+}
+
+KeymapWrapper::ModifierKey* KeymapWrapper::GetModifierKey(
+    guint aHardwareKeycode) {
+  for (uint32_t i = 0; i < mModifierKeys.Length(); i++) {
+    ModifierKey& key = mModifierKeys[i];
+    if (key.mHardwareKeycode == aHardwareKeycode) {
+      return &key;
+    }
+  }
+  return nullptr;
+}
+
+/* static */
+KeymapWrapper* KeymapWrapper::GetInstance() {
+  if (!sInstance) {
+    sInstance = new KeymapWrapper();
+    sInstance->Init();
+  }
+  return sInstance;
+}
+
+#ifdef MOZ_WAYLAND
+void KeymapWrapper::EnsureInstance() { (void)GetInstance(); }
+
+void KeymapWrapper::InitBySystemSettingsWayland() {
+  MOZ_UNUSED(WaylandDisplayGet());
+}
+#endif
+
+/* static */
+void KeymapWrapper::Shutdown() {
+  if (sInstance) {
+    delete sInstance;
+    sInstance = nullptr;
+  }
+}
+
+KeymapWrapper::KeymapWrapper()
+    : mInitialized(false),
+      mGdkKeymap(gdk_keymap_get_default()),
+      mXKBBaseEventCode(0),
+      mOnKeysChangedSignalHandle(0),
+      mOnDirectionChangedSignalHandle(0) {
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p Constructor, mGdkKeymap=%p", this, mGdkKeymap));
+
+  g_object_ref(mGdkKeymap);
+
+#ifdef MOZ_X11
+  if (GdkIsX11Display()) {
+    InitXKBExtension();
+  }
+#endif
+}
+
+void KeymapWrapper::Init() {
+  if (mInitialized) {
+    return;
+  }
+  mInitialized = true;
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p Init, mGdkKeymap=%p", this, mGdkKeymap));
+
+  mModifierKeys.Clear();
+  memset(mModifierMasks, 0, sizeof(mModifierMasks));
+
+#ifdef MOZ_X11
+  if (GdkIsX11Display()) {
+    InitBySystemSettingsX11();
+  }
+#endif
+#ifdef MOZ_WAYLAND
+  if (GdkIsWaylandDisplay()) {
+    InitBySystemSettingsWayland();
+  }
+#endif
+
+#ifdef MOZ_X11
+  gdk_window_add_filter(nullptr, FilterEvents, this);
+#endif
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p Init, CapsLock=0x%X, NumLock=0x%X, "
+           "ScrollLock=0x%X, Level3=0x%X, Level5=0x%X, "
+           "Shift=0x%X, Ctrl=0x%X, Alt=0x%X, Meta=0x%X, Super=0x%X, Hyper=0x%X",
+           this, GetGdkModifierMask(CAPS_LOCK), GetGdkModifierMask(NUM_LOCK),
+           GetGdkModifierMask(SCROLL_LOCK), GetGdkModifierMask(LEVEL3),
+           GetGdkModifierMask(LEVEL5), GetGdkModifierMask(SHIFT),
+           GetGdkModifierMask(CTRL), GetGdkModifierMask(ALT),
+           GetGdkModifierMask(META), GetGdkModifierMask(SUPER),
+           GetGdkModifierMask(HYPER)));
+}
+
+#ifdef MOZ_X11
+void KeymapWrapper::InitXKBExtension() {
+  PodZero(&mKeyboardState);
+
+  int xkbMajorVer = XkbMajorVersion;
+  int xkbMinorVer = XkbMinorVersion;
+  if (!XkbLibraryVersion(&xkbMajorVer, &xkbMinorVer)) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p InitXKBExtension failed due to failure of "
+             "XkbLibraryVersion()",
+             this));
+    return;
+  }
+
+  Display* display = gdk_x11_display_get_xdisplay(gdk_display_get_default());
+
+  // XkbLibraryVersion() set xkbMajorVer and xkbMinorVer to that of the
+  // library, which may be newer than what is required of the server in
+  // XkbQueryExtension(), so these variables should be reset to
+  // XkbMajorVersion and XkbMinorVersion before the XkbQueryExtension call.
+  xkbMajorVer = XkbMajorVersion;
+  xkbMinorVer = XkbMinorVersion;
+  int opcode, baseErrorCode;
+  if (!XkbQueryExtension(display, &opcode, &mXKBBaseEventCode, &baseErrorCode,
+                         &xkbMajorVer, &xkbMinorVer)) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   InitXKBExtension failed due to failure of "
+             "XkbQueryExtension(), display=0x%p",
+             this, display));
+    return;
+  }
+
+  if (!XkbSelectEventDetails(display, XkbUseCoreKbd, XkbStateNotify,
+                             XkbModifierStateMask, XkbModifierStateMask)) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   InitXKBExtension failed due to failure of "
+             "XkbSelectEventDetails() for XModifierStateMask, display=0x%p",
+             this, display));
+    return;
+  }
+
+  if (!XkbSelectEventDetails(display, XkbUseCoreKbd, XkbControlsNotify,
+                             XkbPerKeyRepeatMask, XkbPerKeyRepeatMask)) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   InitXKBExtension failed due to failure of "
+             "XkbSelectEventDetails() for XkbControlsNotify, display=0x%p",
+             this, display));
+    return;
+  }
+
+  if (!XGetKeyboardControl(display, &mKeyboardState)) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   InitXKBExtension failed due to failure of "
+             "XGetKeyboardControl(), display=0x%p",
+             this, display));
+    return;
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Info, ("%p   InitXKBExtension, Succeeded", this));
+}
+
+void KeymapWrapper::InitBySystemSettingsX11() {
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p InitBySystemSettingsX11, mGdkKeymap=%p", this, mGdkKeymap));
+
+  if (!mOnKeysChangedSignalHandle) {
+    mOnKeysChangedSignalHandle = g_signal_connect(
+        mGdkKeymap, "keys-changed", (GCallback)OnKeysChanged, this);
+  }
+  if (!mOnDirectionChangedSignalHandle) {
+    mOnDirectionChangedSignalHandle = g_signal_connect(
+        mGdkKeymap, "direction-changed", (GCallback)OnDirectionChanged, this);
+  }
+
+  Display* display = gdk_x11_display_get_xdisplay(gdk_display_get_default());
+
+  int min_keycode = 0;
+  int max_keycode = 0;
+  XDisplayKeycodes(display, &min_keycode, &max_keycode);
+
+  int keysyms_per_keycode = 0;
+  KeySym* xkeymap =
+      XGetKeyboardMapping(display, min_keycode, max_keycode - min_keycode + 1,
+                          &keysyms_per_keycode);
+  if (!xkeymap) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   InitBySystemSettings, "
+             "Failed due to null xkeymap",
+             this));
+    return;
+  }
+
+  XModifierKeymap* xmodmap = XGetModifierMapping(display);
+  if (!xmodmap) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   InitBySystemSettings, "
+             "Failed due to null xmodmap",
+             this));
+    XFree(xkeymap);
+    return;
+  }
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   InitBySystemSettings, min_keycode=%d, "
+           "max_keycode=%d, keysyms_per_keycode=%d, max_keypermod=%d",
+           this, min_keycode, max_keycode, keysyms_per_keycode,
+           xmodmap->max_keypermod));
+
+  // The modifiermap member of the XModifierKeymap structure contains 8 sets
+  // of max_keypermod KeyCodes, one for each modifier in the order Shift,
+  // Lock, Control, Mod1, Mod2, Mod3, Mod4, and Mod5.
+  // Only nonzero KeyCodes have meaning in each set, and zero KeyCodes are
+  // ignored.
+
+  // Note that two or more modifiers may use one modifier flag.  E.g.,
+  // on Ubuntu 10.10, Alt and Meta share the Mod1 in default settings.
+  // And also Super and Hyper share the Mod4. In such cases, we need to
+  // decide which modifier flag means one of DOM modifiers.
+
+  // mod[0] is Modifier introduced by Mod1.
+  MappedModifier mod[5];
+  int32_t foundLevel[5];
+  for (uint32_t i = 0; i < ArrayLength(mod); i++) {
+    mod[i] = NOT_MODIFIER;
+    foundLevel[i] = INT32_MAX;
+  }
+  const uint32_t map_size = 8 * xmodmap->max_keypermod;
+  for (uint32_t i = 0; i < map_size; i++) {
+    KeyCode keycode = xmodmap->modifiermap[i];
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   InitBySystemSettings, "
+             "  i=%d, keycode=0x%08X",
+             this, i, keycode));
+    if (!keycode || keycode < min_keycode || keycode > max_keycode) {
+      continue;
+    }
+
+    ModifierKey* modifierKey = GetModifierKey(keycode);
+    if (!modifierKey) {
+      modifierKey = mModifierKeys.AppendElement(ModifierKey(keycode));
+    }
+
+    const KeySym* syms =
+        xkeymap + (keycode - min_keycode) * keysyms_per_keycode;
+    const uint32_t bit = i / xmodmap->max_keypermod;
+    modifierKey->mMask |= 1 << bit;
+
+    // We need to know the meaning of Mod1, Mod2, Mod3, Mod4 and Mod5.
+    // Let's skip if current map is for others.
+    if (bit < 3) {
+      continue;
+    }
+
+    const int32_t modIndex = bit - 3;
+    for (int32_t j = 0; j < keysyms_per_keycode; j++) {
+      MappedModifier modifier = GetModifierForGDKKeyval(syms[j]);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   InitBySystemSettings, "
+               "    Mod%d, j=%d, syms[j]=%s(0x%lX), modifier=%s",
+               this, modIndex + 1, j, gdk_keyval_name(syms[j]), syms[j],
+               GetModifierName(modifier)));
+
+      switch (modifier) {
+        case NOT_MODIFIER:
+          // Don't overwrite the stored information with
+          // NOT_MODIFIER.
+          break;
+        case CAPS_LOCK:
+        case SHIFT:
+        case CTRL:
+        case SUPER:
+          // Ignore the modifiers defined in GDK spec. They shouldn't
+          // be mapped to Mod1-5 because they must not work on native
+          // GTK applications.
+          break;
+        default:
+          // If new modifier is found in higher level than stored
+          // value, we don't need to overwrite it.
+          if (j > foundLevel[modIndex]) {
+            break;
+          }
+          // If new modifier is more important than stored value,
+          // we should overwrite it with new modifier.
+          if (j == foundLevel[modIndex]) {
+            mod[modIndex] = std::min(modifier, mod[modIndex]);
+            break;
+          }
+          foundLevel[modIndex] = j;
+          mod[modIndex] = modifier;
+          break;
+      }
+    }
+  }
+
+  for (uint32_t i = 0; i < COUNT_OF_MODIFIER_INDEX; i++) {
+    MappedModifier modifier;
+    switch (i) {
+      case INDEX_NUM_LOCK:
+        modifier = NUM_LOCK;
+        break;
+      case INDEX_SCROLL_LOCK:
+        modifier = SCROLL_LOCK;
+        break;
+      case INDEX_ALT:
+        modifier = ALT;
+        break;
+      case INDEX_META:
+        modifier = META;
+        break;
+      case INDEX_HYPER:
+        modifier = HYPER;
+        break;
+      case INDEX_LEVEL3:
+        modifier = LEVEL3;
+        break;
+      case INDEX_LEVEL5:
+        modifier = LEVEL5;
+        break;
+      default:
+        MOZ_CRASH("All indexes must be handled here");
+    }
+    for (uint32_t j = 0; j < ArrayLength(mod); j++) {
+      if (modifier == mod[j]) {
+        mModifierMasks[i] |= 1 << (j + 3);
+      }
+    }
+  }
+
+  XFreeModifiermap(xmodmap);
+  XFree(xkeymap);
+}
+#endif
+
+#ifdef MOZ_WAYLAND
+void KeymapWrapper::SetModifierMask(xkb_keymap* aKeymap,
+                                    ModifierIndex aModifierIndex,
+                                    const char* aModifierName) {
+  static auto sXkbKeymapModGetIndex =
+      (xkb_mod_index_t(*)(struct xkb_keymap*, const char*))dlsym(
+          RTLD_DEFAULT, "xkb_keymap_mod_get_index");
+
+  xkb_mod_index_t index = sXkbKeymapModGetIndex(aKeymap, aModifierName);
+  if (index != XKB_MOD_INVALID) {
+    mModifierMasks[aModifierIndex] = (1 << index);
+  }
+}
+
+void KeymapWrapper::SetModifierMasks(xkb_keymap* aKeymap) {
+  KeymapWrapper* keymapWrapper = GetInstance();
+
+  // This mapping is derived from get_xkb_modifiers() at gdkkeys-wayland.c
+  keymapWrapper->SetModifierMask(aKeymap, INDEX_NUM_LOCK, XKB_MOD_NAME_NUM);
+  keymapWrapper->SetModifierMask(aKeymap, INDEX_ALT, XKB_MOD_NAME_ALT);
+  keymapWrapper->SetModifierMask(aKeymap, INDEX_META, "Meta");
+  keymapWrapper->SetModifierMask(aKeymap, INDEX_HYPER, "Hyper");
+
+  keymapWrapper->SetModifierMask(aKeymap, INDEX_SCROLL_LOCK, "ScrollLock");
+  keymapWrapper->SetModifierMask(aKeymap, INDEX_LEVEL3, "Level3");
+  keymapWrapper->SetModifierMask(aKeymap, INDEX_LEVEL5, "Level5");
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p KeymapWrapper::SetModifierMasks, CapsLock=0x%X, NumLock=0x%X, "
+           "ScrollLock=0x%X, Level3=0x%X, Level5=0x%X, "
+           "Shift=0x%X, Ctrl=0x%X, Alt=0x%X, Meta=0x%X, Super=0x%X, Hyper=0x%X",
+           keymapWrapper, keymapWrapper->GetGdkModifierMask(CAPS_LOCK),
+           keymapWrapper->GetGdkModifierMask(NUM_LOCK),
+           keymapWrapper->GetGdkModifierMask(SCROLL_LOCK),
+           keymapWrapper->GetGdkModifierMask(LEVEL3),
+           keymapWrapper->GetGdkModifierMask(LEVEL5),
+           keymapWrapper->GetGdkModifierMask(SHIFT),
+           keymapWrapper->GetGdkModifierMask(CTRL),
+           keymapWrapper->GetGdkModifierMask(ALT),
+           keymapWrapper->GetGdkModifierMask(META),
+           keymapWrapper->GetGdkModifierMask(SUPER),
+           keymapWrapper->GetGdkModifierMask(HYPER)));
+}
+
+/* This keymap routine is derived from weston-2.0.0/clients/simple-im.c
+ */
+static void keyboard_handle_keymap(void* data, struct wl_keyboard* wl_keyboard,
+                                   uint32_t format, int fd, uint32_t size) {
+  KeymapWrapper::ResetKeyboard();
+
+  if (format != WL_KEYBOARD_KEYMAP_FORMAT_XKB_V1) {
+    close(fd);
+    return;
+  }
+
+  char* mapString = (char*)mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
+  if (mapString == MAP_FAILED) {
+    close(fd);
+    return;
+  }
+
+  static auto sXkbContextNew =
+      (struct xkb_context * (*)(enum xkb_context_flags))
+          dlsym(RTLD_DEFAULT, "xkb_context_new");
+  static auto sXkbKeymapNewFromString =
+      (struct xkb_keymap * (*)(struct xkb_context*, const char*,
+                               enum xkb_keymap_format,
+                               enum xkb_keymap_compile_flags))
+          dlsym(RTLD_DEFAULT, "xkb_keymap_new_from_string");
+
+  struct xkb_context* xkb_context = sXkbContextNew(XKB_CONTEXT_NO_FLAGS);
+  struct xkb_keymap* keymap =
+      sXkbKeymapNewFromString(xkb_context, mapString, XKB_KEYMAP_FORMAT_TEXT_V1,
+                              XKB_KEYMAP_COMPILE_NO_FLAGS);
+
+  munmap(mapString, size);
+  close(fd);
+
+  if (!keymap) {
+    NS_WARNING("keyboard_handle_keymap(): Failed to compile keymap!\n");
+    return;
+  }
+
+  KeymapWrapper::SetModifierMasks(keymap);
+
+  static auto sXkbKeymapUnRef =
+      (void (*)(struct xkb_keymap*))dlsym(RTLD_DEFAULT, "xkb_keymap_unref");
+  sXkbKeymapUnRef(keymap);
+
+  static auto sXkbContextUnref =
+      (void (*)(struct xkb_context*))dlsym(RTLD_DEFAULT, "xkb_context_unref");
+  sXkbContextUnref(xkb_context);
+}
+
+static void keyboard_handle_enter(void* data, struct wl_keyboard* keyboard,
+                                  uint32_t serial, struct wl_surface* surface,
+                                  struct wl_array* keys) {
+  KeymapWrapper::SetFocusIn(surface, serial);
+}
+
+static void keyboard_handle_leave(void* data, struct wl_keyboard* keyboard,
+                                  uint32_t serial, struct wl_surface* surface) {
+  KeymapWrapper::SetFocusOut(surface);
+}
+
+static void keyboard_handle_key(void* data, struct wl_keyboard* keyboard,
+                                uint32_t serial, uint32_t time, uint32_t key,
+                                uint32_t state) {}
+static void keyboard_handle_modifiers(void* data, struct wl_keyboard* keyboard,
+                                      uint32_t serial, uint32_t mods_depressed,
+                                      uint32_t mods_latched,
+                                      uint32_t mods_locked, uint32_t group) {}
+static void keyboard_handle_repeat_info(void* data,
+                                        struct wl_keyboard* keyboard,
+                                        int32_t rate, int32_t delay) {}
+
+static const struct wl_keyboard_listener keyboard_listener = {
+    keyboard_handle_keymap,    keyboard_handle_enter,
+    keyboard_handle_leave,     keyboard_handle_key,
+    keyboard_handle_modifiers, keyboard_handle_repeat_info};
+
+static void seat_handle_capabilities(void* data, struct wl_seat* seat,
+                                     unsigned int caps) {
+  wl_keyboard* keyboard = KeymapWrapper::GetKeyboard();
+  if ((caps & WL_SEAT_CAPABILITY_KEYBOARD) && !keyboard) {
+    keyboard = wl_seat_get_keyboard(seat);
+    wl_keyboard_add_listener(keyboard, &keyboard_listener, nullptr);
+    KeymapWrapper::SetKeyboard(keyboard);
+  } else if (!(caps & WL_SEAT_CAPABILITY_KEYBOARD) && keyboard) {
+    KeymapWrapper::ClearKeyboard();
+  }
+}
+
+static const struct wl_seat_listener seat_listener = {
+    seat_handle_capabilities,
+};
+
+#endif
+
+KeymapWrapper::~KeymapWrapper() {
+#ifdef MOZ_X11
+  gdk_window_remove_filter(nullptr, FilterEvents, this);
+#endif
+  if (mOnKeysChangedSignalHandle) {
+    g_signal_handler_disconnect(mGdkKeymap, mOnKeysChangedSignalHandle);
+  }
+  if (mOnDirectionChangedSignalHandle) {
+    g_signal_handler_disconnect(mGdkKeymap, mOnDirectionChangedSignalHandle);
+  }
+  g_object_unref(mGdkKeymap);
+  MOZ_LOG(gKeyLog, LogLevel::Info, ("%p Destructor", this));
+}
+
+#ifdef MOZ_X11
+/* static */
+GdkFilterReturn KeymapWrapper::FilterEvents(GdkXEvent* aXEvent,
+                                            GdkEvent* aGdkEvent,
+                                            gpointer aData) {
+  XEvent* xEvent = static_cast<XEvent*>(aXEvent);
+  switch (xEvent->type) {
+    case KeyPress: {
+      // If the key doesn't support auto repeat, ignore the event because
+      // even if such key (e.g., Shift) is pressed during auto repeat of
+      // anoter key, it doesn't stop the auto repeat.
+      KeymapWrapper* self = static_cast<KeymapWrapper*>(aData);
+      if (!self->IsAutoRepeatableKey(xEvent->xkey.keycode)) {
+        break;
+      }
+      if (sRepeatState == NOT_PRESSED) {
+        sRepeatState = FIRST_PRESS;
+        MOZ_LOG(gKeyLog, LogLevel::Info,
+                ("FilterEvents(aXEvent={ type=KeyPress, "
+                 "xkey={ keycode=0x%08X, state=0x%08X, time=%lu } }, "
+                 "aGdkEvent={ state=0x%08X }), "
+                 "detected first keypress",
+                 xEvent->xkey.keycode, xEvent->xkey.state, xEvent->xkey.time,
+                 reinterpret_cast<GdkEventKey*>(aGdkEvent)->state));
+      } else if (sLastRepeatableHardwareKeyCode == xEvent->xkey.keycode) {
+        if (sLastRepeatableKeyTime == xEvent->xkey.time &&
+            sLastRepeatableHardwareKeyCode ==
+                IMContextWrapper::
+                    GetWaitingSynthesizedKeyPressHardwareKeyCode()) {
+          // On some environment, IM may generate duplicated KeyPress event
+          // without any special state flags.  In such case, we shouldn't
+          // treat the event as "repeated".
+          MOZ_LOG(gKeyLog, LogLevel::Info,
+                  ("FilterEvents(aXEvent={ type=KeyPress, "
+                   "xkey={ keycode=0x%08X, state=0x%08X, time=%lu } }, "
+                   "aGdkEvent={ state=0x%08X }), "
+                   "igored keypress since it must be synthesized by IME",
+                   xEvent->xkey.keycode, xEvent->xkey.state, xEvent->xkey.time,
+                   reinterpret_cast<GdkEventKey*>(aGdkEvent)->state));
+          break;
+        }
+        sRepeatState = REPEATING;
+        MOZ_LOG(gKeyLog, LogLevel::Info,
+                ("FilterEvents(aXEvent={ type=KeyPress, "
+                 "xkey={ keycode=0x%08X, state=0x%08X, time=%lu } }, "
+                 "aGdkEvent={ state=0x%08X }), "
+                 "detected repeating keypress",
+                 xEvent->xkey.keycode, xEvent->xkey.state, xEvent->xkey.time,
+                 reinterpret_cast<GdkEventKey*>(aGdkEvent)->state));
+      } else {
+        // If a different key is pressed while another key is pressed,
+        // auto repeat system repeats only the last pressed key.
+        // So, setting new keycode and setting repeat state as first key
+        // press should work fine.
+        sRepeatState = FIRST_PRESS;
+        MOZ_LOG(gKeyLog, LogLevel::Info,
+                ("FilterEvents(aXEvent={ type=KeyPress, "
+                 "xkey={ keycode=0x%08X, state=0x%08X, time=%lu } }, "
+                 "aGdkEvent={ state=0x%08X }), "
+                 "detected different keypress",
+                 xEvent->xkey.keycode, xEvent->xkey.state, xEvent->xkey.time,
+                 reinterpret_cast<GdkEventKey*>(aGdkEvent)->state));
+      }
+      sLastRepeatableHardwareKeyCode = xEvent->xkey.keycode;
+      sLastRepeatableKeyTime = xEvent->xkey.time;
+      break;
+    }
+    case KeyRelease: {
+      if (sLastRepeatableHardwareKeyCode != xEvent->xkey.keycode) {
+        // This case means the key release event is caused by
+        // a non-repeatable key such as Shift or a repeatable key that
+        // was pressed before sLastRepeatableHardwareKeyCode was
+        // pressed.
+        break;
+      }
+      sRepeatState = NOT_PRESSED;
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("FilterEvents(aXEvent={ type=KeyRelease, "
+               "xkey={ keycode=0x%08X, state=0x%08X, time=%lu } }, "
+               "aGdkEvent={ state=0x%08X }), "
+               "detected key release",
+               xEvent->xkey.keycode, xEvent->xkey.state, xEvent->xkey.time,
+               reinterpret_cast<GdkEventKey*>(aGdkEvent)->state));
+      break;
+    }
+    case FocusOut: {
+      // At moving focus, we should reset keyboard repeat state.
+      // Strictly, this causes incorrect behavior.  However, this
+      // correctness must be enough for web applications.
+      sRepeatState = NOT_PRESSED;
+      break;
+    }
+    default: {
+      KeymapWrapper* self = static_cast<KeymapWrapper*>(aData);
+      if (xEvent->type != self->mXKBBaseEventCode) {
+        break;
+      }
+      XkbEvent* xkbEvent = (XkbEvent*)xEvent;
+      if (xkbEvent->any.xkb_type != XkbControlsNotify ||
+          !(xkbEvent->ctrls.changed_ctrls & XkbPerKeyRepeatMask)) {
+        break;
+      }
+      if (!XGetKeyboardControl(xkbEvent->any.display, &self->mKeyboardState)) {
+        MOZ_LOG(gKeyLog, LogLevel::Info,
+                ("%p FilterEvents failed due to failure "
+                 "of XGetKeyboardControl(), display=0x%p",
+                 self, xkbEvent->any.display));
+      }
+      break;
+    }
+  }
+
+  return GDK_FILTER_CONTINUE;
+}
+#endif
+
+static void ResetBidiKeyboard() {
+  // Reset the bidi keyboard settings for the new GdkKeymap
+  nsCOMPtr<nsIBidiKeyboard> bidiKeyboard = nsContentUtils::GetBidiKeyboard();
+  if (bidiKeyboard) {
+    bidiKeyboard->Reset();
+  }
+  WidgetUtils::SendBidiKeyboardInfoToContent();
+}
+
+/* static */
+void KeymapWrapper::ResetKeyboard() {
+  if (sInstance) {
+    sInstance->mInitialized = false;
+    ResetBidiKeyboard();
+  }
+}
+
+/* static */
+void KeymapWrapper::OnKeysChanged(GdkKeymap* aGdkKeymap,
+                                  KeymapWrapper* aKeymapWrapper) {
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("OnKeysChanged, aGdkKeymap=%p, aKeymapWrapper=%p", aGdkKeymap,
+           aKeymapWrapper));
+
+  MOZ_ASSERT(sInstance == aKeymapWrapper,
+             "This instance must be the singleton instance");
+
+  // We cannot reintialize here becasue we don't have GdkWindow which is using
+  // the GdkKeymap.  We'll reinitialize it when next GetInstance() is called.
+  ResetKeyboard();
+}
+
+// static
+void KeymapWrapper::OnDirectionChanged(GdkKeymap* aGdkKeymap,
+                                       KeymapWrapper* aKeymapWrapper) {
+  // XXX
+  // A lot of diretion-changed signal might be fired on switching bidi
+  // keyboard when using both ibus (with arabic layout) and fcitx (with IME).
+  // See https://github.com/fcitx/fcitx/issues/257
+  //
+  // Also, when using ibus, switching to IM might not cause this signal.
+  // See https://github.com/ibus/ibus/issues/1848
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("OnDirectionChanged, aGdkKeymap=%p, aKeymapWrapper=%p", aGdkKeymap,
+           aKeymapWrapper));
+
+  ResetBidiKeyboard();
+}
+
+/* static */
+guint KeymapWrapper::GetCurrentModifierState() {
+  GdkModifierType modifiers;
+  GdkDisplay* display = gdk_display_get_default();
+  GdkScreen* screen = gdk_display_get_default_screen(display);
+  GdkWindow* window = gdk_screen_get_root_window(screen);
+  gdk_window_get_device_position(window, GdkGetPointer(), nullptr, nullptr,
+                                 &modifiers);
+  return static_cast<guint>(modifiers);
+}
+
+/* static */
+bool KeymapWrapper::AreModifiersActive(MappedModifiers aModifiers,
+                                       guint aGdkModifierState) {
+  NS_ENSURE_TRUE(aModifiers, false);
+
+  KeymapWrapper* keymapWrapper = GetInstance();
+  for (uint32_t i = 0; i < sizeof(MappedModifier) * 8 && aModifiers; i++) {
+    MappedModifier modifier = static_cast<MappedModifier>(1 << i);
+    // Is the binary position used by modifier?
+    if (!(aModifiers & modifier)) {
+      continue;
+    }
+    // Is the modifier active?
+    if (!(aGdkModifierState & keymapWrapper->GetGdkModifierMask(modifier))) {
+      return false;
+    }
+    aModifiers &= ~modifier;
+  }
+  return true;
+}
+
+/* static */
+uint32_t KeymapWrapper::ComputeCurrentKeyModifiers() {
+  return ComputeKeyModifiers(GetCurrentModifierState());
+}
+
+/* static */
+uint32_t KeymapWrapper::ComputeKeyModifiers(guint aGdkModifierState) {
+  uint32_t keyModifiers = 0;
+  if (!aGdkModifierState) {
+    return keyModifiers;
+  }
+
+  // DOM Meta key should be TRUE only on Mac.  We need to discuss this
+  // issue later.
+  KeymapWrapper* keymapWrapper = GetInstance();
+  if (keymapWrapper->AreModifiersActive(SHIFT, aGdkModifierState)) {
+    keyModifiers |= MODIFIER_SHIFT;
+  }
+  if (keymapWrapper->AreModifiersActive(CTRL, aGdkModifierState)) {
+    keyModifiers |= MODIFIER_CONTROL;
+  }
+  if (keymapWrapper->AreModifiersActive(ALT, aGdkModifierState)) {
+    keyModifiers |= MODIFIER_ALT;
+  }
+  if (keymapWrapper->AreModifiersActive(SUPER, aGdkModifierState) ||
+      keymapWrapper->AreModifiersActive(HYPER, aGdkModifierState) ||
+      // "Meta" state is typically mapped to `Alt` + `Shift`, but we ignore the
+      // state if `Alt` is mapped to "Alt" state.  Additionally it's mapped to
+      // `Win` in Sun/Solaris keyboard layout.  In this case, we want to treat
+      // them as DOM Meta modifier keys like "Super" state in the major Linux
+      // environments.
+      keymapWrapper->AreModifiersActive(META, aGdkModifierState)) {
+    keyModifiers |= MODIFIER_META;
+  }
+  if (keymapWrapper->AreModifiersActive(LEVEL3, aGdkModifierState) ||
+      keymapWrapper->AreModifiersActive(LEVEL5, aGdkModifierState)) {
+    keyModifiers |= MODIFIER_ALTGRAPH;
+  }
+  if (keymapWrapper->AreModifiersActive(CAPS_LOCK, aGdkModifierState)) {
+    keyModifiers |= MODIFIER_CAPSLOCK;
+  }
+  if (keymapWrapper->AreModifiersActive(NUM_LOCK, aGdkModifierState)) {
+    keyModifiers |= MODIFIER_NUMLOCK;
+  }
+  if (keymapWrapper->AreModifiersActive(SCROLL_LOCK, aGdkModifierState)) {
+    keyModifiers |= MODIFIER_SCROLLLOCK;
+  }
+  return keyModifiers;
+}
+
+/* static */
+guint KeymapWrapper::ConvertWidgetModifierToGdkState(
+    nsIWidget::Modifiers aNativeModifiers) {
+  if (!aNativeModifiers) {
+    return 0;
+  }
+  struct ModifierMapEntry {
+    nsIWidget::Modifiers mWidgetModifier;
+    MappedModifier mModifier;
+  };
+  // TODO: Currently, we don't treat L/R of each modifier on Linux.
+  // TODO: No proper native modifier for Level5.
+  static constexpr ModifierMapEntry sModifierMap[] = {
+      {nsIWidget::CAPS_LOCK, MappedModifier::CAPS_LOCK},
+      {nsIWidget::NUM_LOCK, MappedModifier::NUM_LOCK},
+      {nsIWidget::SHIFT_L, MappedModifier::SHIFT},
+      {nsIWidget::SHIFT_R, MappedModifier::SHIFT},
+      {nsIWidget::CTRL_L, MappedModifier::CTRL},
+      {nsIWidget::CTRL_R, MappedModifier::CTRL},
+      {nsIWidget::ALT_L, MappedModifier::ALT},
+      {nsIWidget::ALT_R, MappedModifier::ALT},
+      {nsIWidget::ALTGRAPH, MappedModifier::LEVEL3},
+      {nsIWidget::COMMAND_L, MappedModifier::SUPER},
+      {nsIWidget::COMMAND_R, MappedModifier::SUPER}};
+
+  guint state = 0;
+  KeymapWrapper* instance = GetInstance();
+  for (const ModifierMapEntry& entry : sModifierMap) {
+    if (aNativeModifiers & entry.mWidgetModifier) {
+      state |= instance->GetGdkModifierMask(entry.mModifier);
+    }
+  }
+  return state;
+}
+
+/* static */
+void KeymapWrapper::InitInputEvent(WidgetInputEvent& aInputEvent,
+                                   guint aGdkModifierState) {
+  KeymapWrapper* keymapWrapper = GetInstance();
+
+  aInputEvent.mModifiers = ComputeKeyModifiers(aGdkModifierState);
+
+  // Don't log this method for non-important events because e.g., eMouseMove is
+  // just noisy and there is no reason to log it.
+  bool doLog = aInputEvent.mMessage != eMouseMove;
+  if (doLog) {
+    MOZ_LOG(gKeyLog, LogLevel::Debug,
+            ("%p InitInputEvent, aGdkModifierState=0x%08X, "
+             "aInputEvent={ mMessage=%s, mModifiers=0x%04X (Shift: %s, "
+             "Control: %s, Alt: %s, Meta: %s, AltGr: %s, "
+             "CapsLock: %s, NumLock: %s, ScrollLock: %s })",
+             keymapWrapper, aGdkModifierState, ToChar(aInputEvent.mMessage),
+             aInputEvent.mModifiers,
+             GetBoolName(aInputEvent.mModifiers & MODIFIER_SHIFT),
+             GetBoolName(aInputEvent.mModifiers & MODIFIER_CONTROL),
+             GetBoolName(aInputEvent.mModifiers & MODIFIER_ALT),
+             GetBoolName(aInputEvent.mModifiers & MODIFIER_META),
+             GetBoolName(aInputEvent.mModifiers & MODIFIER_ALTGRAPH),
+             GetBoolName(aInputEvent.mModifiers & MODIFIER_CAPSLOCK),
+             GetBoolName(aInputEvent.mModifiers & MODIFIER_NUMLOCK),
+             GetBoolName(aInputEvent.mModifiers & MODIFIER_SCROLLLOCK)));
+  }
+
+  switch (aInputEvent.mClass) {
+    case eMouseEventClass:
+    case eMouseScrollEventClass:
+    case eWheelEventClass:
+    case eDragEventClass:
+    case eSimpleGestureEventClass:
+      break;
+    default:
+      return;
+  }
+
+  WidgetMouseEventBase& mouseEvent = *aInputEvent.AsMouseEventBase();
+  mouseEvent.mButtons = 0;
+  if (aGdkModifierState & GDK_BUTTON1_MASK) {
+    mouseEvent.mButtons |= MouseButtonsFlag::ePrimaryFlag;
+  }
+  if (aGdkModifierState & GDK_BUTTON3_MASK) {
+    mouseEvent.mButtons |= MouseButtonsFlag::eSecondaryFlag;
+  }
+  if (aGdkModifierState & GDK_BUTTON2_MASK) {
+    mouseEvent.mButtons |= MouseButtonsFlag::eMiddleFlag;
+  }
+
+  if (doLog) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Debug,
+        ("%p   InitInputEvent, aInputEvent has mButtons, "
+         "aInputEvent.mButtons=0x%04X (Left: %s, Right: %s, Middle: %s, "
+         "4th (BACK): %s, 5th (FORWARD): %s)",
+         keymapWrapper, mouseEvent.mButtons,
+         GetBoolName(mouseEvent.mButtons & MouseButtonsFlag::ePrimaryFlag),
+         GetBoolName(mouseEvent.mButtons & MouseButtonsFlag::eSecondaryFlag),
+         GetBoolName(mouseEvent.mButtons & MouseButtonsFlag::eMiddleFlag),
+         GetBoolName(mouseEvent.mButtons & MouseButtonsFlag::e4thFlag),
+         GetBoolName(mouseEvent.mButtons & MouseButtonsFlag::e5thFlag)));
+  }
+}
+
+/* static */
+uint32_t KeymapWrapper::ComputeDOMKeyCode(const GdkEventKey* aGdkKeyEvent) {
+  // If the keyval indicates it's a modifier key, we should use unshifted
+  // key's modifier keyval.
+  guint keyval = aGdkKeyEvent->keyval;
+  if (GetModifierForGDKKeyval(keyval)) {
+    // But if the keyval without modifiers isn't a modifier key, we
+    // shouldn't use it.  E.g., Japanese keyboard layout's
+    // Shift + Eisu-Toggle key is CapsLock.  This is an actual rare case,
+    // Windows uses different keycode for a physical key for different
+    // shift key state.
+    guint keyvalWithoutModifier = GetGDKKeyvalWithoutModifier(aGdkKeyEvent);
+    if (GetModifierForGDKKeyval(keyvalWithoutModifier)) {
+      keyval = keyvalWithoutModifier;
+    }
+    // Note that the modifier keycode and activating or deactivating
+    // modifier flag may be mismatched, but it's okay.  If a DOM key
+    // event handler is testing a keydown event, it's more likely being
+    // used to test which key is being pressed than to test which
+    // modifier will become active.  So, if we computed DOM keycode
+    // from modifier flag which were changing by the physical key, then
+    // there would be no other way for the user to generate the original
+    // keycode.
+    uint32_t DOMKeyCode = GetDOMKeyCodeFromKeyPairs(keyval);
+    NS_ASSERTION(DOMKeyCode, "All modifier keys must have a DOM keycode");
+    return DOMKeyCode;
+  }
+
+  // If the key isn't printable, let's look at the key pairs.
+  uint32_t charCode = GetCharCodeFor(aGdkKeyEvent);
+  if (!charCode) {
+    // Note that any key may be a function key because of some unusual keyboard
+    // layouts.  I.e., even if the pressed key is a printable key of en-US
+    // keyboard layout, we should expose the function key's keyCode value to
+    // web apps because web apps should handle the keydown/keyup events as
+    // inputted by usual keyboard layout.  For example, Hatchak keyboard
+    // maps Tab key to "Digit3" key and Level3 Shift makes it "Backspace".
+    // In this case, we should expose DOM_VK_BACK_SPACE (8).
+    uint32_t DOMKeyCode = GetDOMKeyCodeFromKeyPairs(keyval);
+    if (DOMKeyCode) {
+      // XXX If DOMKeyCode is a function key's keyCode value, it might be
+      //     better to consume necessary modifiers.  For example, if there is
+      //     no Control Pad section on keyboard like notebook, Delete key is
+      //     available only with Level3 Shift+"Backspace" key if using Hatchak.
+      //     If web apps accept Delete key operation only when no modifiers are
+      //     active, such users cannot use Delete key to do it.  However,
+      //     Chromium doesn't consume such necessary modifiers.  So, our default
+      //     behavior should keep not touching modifiers for compatibility, but
+      //     it might be better to add a pref to consume necessary modifiers.
+      return DOMKeyCode;
+    }
+    // If aGdkKeyEvent cannot be mapped to a DOM keyCode value, we should
+    // refer keyCode value without modifiers because web apps should be
+    // able to identify the key as far as possible.
+    guint keyvalWithoutModifier = GetGDKKeyvalWithoutModifier(aGdkKeyEvent);
+    return GetDOMKeyCodeFromKeyPairs(keyvalWithoutModifier);
+  }
+
+  // printable numpad keys should be resolved here.
+  switch (keyval) {
+    case GDK_KP_Multiply:
+      return NS_VK_MULTIPLY;
+    case GDK_KP_Add:
+      return NS_VK_ADD;
+    case GDK_KP_Separator:
+      return NS_VK_SEPARATOR;
+    case GDK_KP_Subtract:
+      return NS_VK_SUBTRACT;
+    case GDK_KP_Decimal:
+      return NS_VK_DECIMAL;
+    case GDK_KP_Divide:
+      return NS_VK_DIVIDE;
+    case GDK_KP_0:
+      return NS_VK_NUMPAD0;
+    case GDK_KP_1:
+      return NS_VK_NUMPAD1;
+    case GDK_KP_2:
+      return NS_VK_NUMPAD2;
+    case GDK_KP_3:
+      return NS_VK_NUMPAD3;
+    case GDK_KP_4:
+      return NS_VK_NUMPAD4;
+    case GDK_KP_5:
+      return NS_VK_NUMPAD5;
+    case GDK_KP_6:
+      return NS_VK_NUMPAD6;
+    case GDK_KP_7:
+      return NS_VK_NUMPAD7;
+    case GDK_KP_8:
+      return NS_VK_NUMPAD8;
+    case GDK_KP_9:
+      return NS_VK_NUMPAD9;
+  }
+
+  KeymapWrapper* keymapWrapper = GetInstance();
+
+  // Ignore all modifier state except NumLock.
+  guint baseState =
+      (aGdkKeyEvent->state & keymapWrapper->GetGdkModifierMask(NUM_LOCK));
+
+  // Basically, we should use unmodified character for deciding our keyCode.
+  uint32_t unmodifiedChar = keymapWrapper->GetCharCodeFor(
+      aGdkKeyEvent, baseState, aGdkKeyEvent->group);
+  if (IsBasicLatinLetterOrNumeral(unmodifiedChar)) {
+    // If the unmodified character is an ASCII alphabet or an ASCII
+    // numeric, it's the best hint for deciding our keyCode.
+    return WidgetUtils::ComputeKeyCodeFromChar(unmodifiedChar);
+  }
+
+  // If the unmodified character is not an ASCII character, that means we
+  // couldn't find the hint. We should reset it.
+  if (!IsPrintableASCIICharacter(unmodifiedChar)) {
+    unmodifiedChar = 0;
+  }
+
+  // Retry with shifted keycode.
+  guint shiftState = (baseState | keymapWrapper->GetGdkModifierMask(SHIFT));
+  uint32_t shiftedChar = keymapWrapper->GetCharCodeFor(aGdkKeyEvent, shiftState,
+                                                       aGdkKeyEvent->group);
+  if (IsBasicLatinLetterOrNumeral(shiftedChar)) {
+    // A shifted character can be an ASCII alphabet on Hebrew keyboard
+    // layout. And also shifted character can be an ASCII numeric on
+    // AZERTY keyboad layout.  Then, it's a good hint for deciding our
+    // keyCode.
+    return WidgetUtils::ComputeKeyCodeFromChar(shiftedChar);
+  }
+
+  // If the shifted unmodified character isn't an ASCII character, we should
+  // discard it too.
+  if (!IsPrintableASCIICharacter(shiftedChar)) {
+    shiftedChar = 0;
+  }
+
+  // If current keyboard layout isn't ASCII alphabet inputtable layout,
+  // look for ASCII alphabet inputtable keyboard layout.  If the key
+  // inputs an ASCII alphabet or an ASCII numeric, we should use it
+  // for deciding our keyCode.
+  uint32_t unmodCharLatin = 0;
+  uint32_t shiftedCharLatin = 0;
+  if (!keymapWrapper->IsLatinGroup(aGdkKeyEvent->group)) {
+    gint minGroup = keymapWrapper->GetFirstLatinGroup();
+    if (minGroup >= 0) {
+      unmodCharLatin =
+          keymapWrapper->GetCharCodeFor(aGdkKeyEvent, baseState, minGroup);
+      if (IsBasicLatinLetterOrNumeral(unmodCharLatin)) {
+        // If the unmodified character is an ASCII alphabet or
+        // an ASCII numeric, we should use it for the keyCode.
+        return WidgetUtils::ComputeKeyCodeFromChar(unmodCharLatin);
+      }
+      // If the unmodified character in the alternative ASCII capable
+      // keyboard layout isn't an ASCII character, that means we couldn't
+      // find the hint. We should reset it.
+      if (!IsPrintableASCIICharacter(unmodCharLatin)) {
+        unmodCharLatin = 0;
+      }
+      shiftedCharLatin =
+          keymapWrapper->GetCharCodeFor(aGdkKeyEvent, shiftState, minGroup);
+      if (IsBasicLatinLetterOrNumeral(shiftedCharLatin)) {
+        // If the shifted character is an ASCII alphabet or an ASCII
+        // numeric, we should use it for the keyCode.
+        return WidgetUtils::ComputeKeyCodeFromChar(shiftedCharLatin);
+      }
+      // If the shifted unmodified character in the alternative ASCII
+      // capable keyboard layout isn't an ASCII character, we should
+      // discard it too.
+      if (!IsPrintableASCIICharacter(shiftedCharLatin)) {
+        shiftedCharLatin = 0;
+      }
+    }
+  }
+
+  // If the key itself or with Shift state on active keyboard layout produces
+  // an ASCII punctuation character, we should decide keyCode value with it.
+  if (unmodifiedChar || shiftedChar) {
+    return WidgetUtils::ComputeKeyCodeFromChar(unmodifiedChar ? unmodifiedChar
+                                                              : shiftedChar);
+  }
+
+  // If the key itself or with Shift state on alternative ASCII capable
+  // keyboard layout produces an ASCII punctuation character, we should
+  // decide keyCode value with it.  Note that We've returned 0 for long
+  // time if keyCode isn't for an alphabet keys or a numeric key even in
+  // alternative ASCII capable keyboard layout because we decided that we
+  // should avoid setting same keyCode value to 2 or more keys since active
+  // keyboard layout may have a key to input the punctuation with different
+  // key.  However, setting keyCode to 0 makes some web applications which
+  // are aware of neither KeyboardEvent.key nor KeyboardEvent.code not work
+  // with Firefox when user selects non-ASCII capable keyboard layout such
+  // as Russian and Thai.  So, if alternative ASCII capable keyboard layout
+  // has keyCode value for the key, we should use it.  In other words, this
+  // behavior means that non-ASCII capable keyboard layout overrides some
+  // keys' keyCode value only if the key produces ASCII character by itself
+  // or with Shift key.
+  if (unmodCharLatin || shiftedCharLatin) {
+    return WidgetUtils::ComputeKeyCodeFromChar(
+        unmodCharLatin ? unmodCharLatin : shiftedCharLatin);
+  }
+
+  // Otherwise, let's decide keyCode value from the hardware_keycode
+  // value on major keyboard layout.
+  CodeNameIndex code = ComputeDOMCodeNameIndex(aGdkKeyEvent);
+  return WidgetKeyboardEvent::GetFallbackKeyCodeOfPunctuationKey(code);
+}
+
+KeyNameIndex KeymapWrapper::ComputeDOMKeyNameIndex(
+    const GdkEventKey* aGdkKeyEvent) {
+  switch (aGdkKeyEvent->keyval) {
+#define NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, aKeyNameIndex) \
+  case aNativeKey:                                                     \
+    return aKeyNameIndex;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+
+    default:
+      break;
+  }
+
+  return KEY_NAME_INDEX_Unidentified;
+}
+
+/* static */
+CodeNameIndex KeymapWrapper::ComputeDOMCodeNameIndex(
+    const GdkEventKey* aGdkKeyEvent) {
+  switch (aGdkKeyEvent->hardware_keycode) {
+#define NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX(aNativeKey, aCodeNameIndex) \
+  case aNativeKey:                                                       \
+    return aCodeNameIndex;
+
+#include "NativeKeyToDOMCodeName.h"
+
+#undef NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX
+
+    default:
+      break;
+  }
+
+  return CODE_NAME_INDEX_UNKNOWN;
+}
+
+/* static */
+bool KeymapWrapper::DispatchKeyDownOrKeyUpEvent(nsWindow* aWindow,
+                                                GdkEventKey* aGdkKeyEvent,
+                                                bool aIsProcessedByIME,
+                                                bool* aIsCancelled) {
+  MOZ_ASSERT(aIsCancelled, "aIsCancelled must not be nullptr");
+
+  *aIsCancelled = false;
+
+  if (aGdkKeyEvent->type == GDK_KEY_PRESS && aGdkKeyEvent->keyval == GDK_Tab &&
+      AreModifiersActive(CTRL | ALT, aGdkKeyEvent->state)) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("  DispatchKeyDownOrKeyUpEvent(), didn't dispatch keyboard events "
+             "because it's Ctrl + Alt + Tab"));
+    return false;
+  }
+
+  EventMessage message =
+      aGdkKeyEvent->type == GDK_KEY_PRESS ? eKeyDown : eKeyUp;
+  WidgetKeyboardEvent keyEvent(true, message, aWindow);
+  KeymapWrapper::InitKeyEvent(keyEvent, aGdkKeyEvent, aIsProcessedByIME);
+  return DispatchKeyDownOrKeyUpEvent(aWindow, keyEvent, aIsCancelled);
+}
+
+/* static */
+bool KeymapWrapper::DispatchKeyDownOrKeyUpEvent(
+    nsWindow* aWindow, WidgetKeyboardEvent& aKeyboardEvent,
+    bool* aIsCancelled) {
+  MOZ_ASSERT(aIsCancelled, "aIsCancelled must not be nullptr");
+
+  *aIsCancelled = false;
+
+  RefPtr<TextEventDispatcher> dispatcher = aWindow->GetTextEventDispatcher();
+  nsresult rv = dispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gKeyLog, LogLevel::Error,
+            ("  DispatchKeyDownOrKeyUpEvent(), stopped dispatching %s event "
+             "because of failed to initialize TextEventDispatcher",
+             ToChar(aKeyboardEvent.mMessage)));
+    return FALSE;
+  }
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  bool dispatched = dispatcher->DispatchKeyboardEvent(
+      aKeyboardEvent.mMessage, aKeyboardEvent, status, nullptr);
+  *aIsCancelled = (status == nsEventStatus_eConsumeNoDefault);
+  return dispatched;
+}
+
+/* static */
+bool KeymapWrapper::MaybeDispatchContextMenuEvent(nsWindow* aWindow,
+                                                  const GdkEventKey* aEvent) {
+  KeyNameIndex keyNameIndex = ComputeDOMKeyNameIndex(aEvent);
+
+  // Shift+F10 and ContextMenu should cause eContextMenu event.
+  if (keyNameIndex != KEY_NAME_INDEX_F10 &&
+      keyNameIndex != KEY_NAME_INDEX_ContextMenu) {
+    return false;
+  }
+
+  WidgetMouseEvent contextMenuEvent(true, eContextMenu, aWindow,
+                                    WidgetMouseEvent::eReal,
+                                    WidgetMouseEvent::eContextMenuKey);
+
+  contextMenuEvent.mRefPoint = LayoutDeviceIntPoint(0, 0);
+  contextMenuEvent.AssignEventTime(aWindow->GetWidgetEventTime(aEvent->time));
+  contextMenuEvent.mClickCount = 1;
+  KeymapWrapper::InitInputEvent(contextMenuEvent, aEvent->state);
+
+  if (contextMenuEvent.IsControl() || contextMenuEvent.IsMeta() ||
+      contextMenuEvent.IsAlt()) {
+    return false;
+  }
+
+  // If the key is ContextMenu, then an eContextMenu mouse event is
+  // dispatched regardless of the state of the Shift modifier.  When it is
+  // pressed without the Shift modifier, a web page can prevent the default
+  // context menu action.  When pressed with the Shift modifier, the web page
+  // cannot prevent the default context menu action.
+  // (PresShell::HandleEventInternal() sets mOnlyChromeDispatch to true.)
+
+  // If the key is F10, it needs Shift state because Shift+F10 is well-known
+  // shortcut key on Linux.  However, eContextMenu with Shift state is
+  // special.  It won't fire "contextmenu" event in the web content for
+  // blocking web page to prevent its default.  Therefore, this combination
+  // should work same as ContextMenu key.
+  // XXX Should we allow to block web page to prevent its default with
+  //     Ctrl+Shift+F10 or Alt+Shift+F10 instead?
+  if (keyNameIndex == KEY_NAME_INDEX_F10) {
+    if (!contextMenuEvent.IsShift()) {
+      return false;
+    }
+    contextMenuEvent.mModifiers &= ~MODIFIER_SHIFT;
+  }
+
+  aWindow->DispatchInputEvent(&contextMenuEvent);
+  return true;
+}
+
+/* static*/
+void KeymapWrapper::HandleKeyPressEvent(nsWindow* aWindow,
+                                        GdkEventKey* aGdkKeyEvent) {
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("HandleKeyPressEvent(aWindow=%p, aGdkKeyEvent={ type=%s, "
+           "keyval=%s(0x%X), state=0x%08X, hardware_keycode=0x%08X, "
+           "time=%u, is_modifier=%s })",
+           aWindow,
+           ((aGdkKeyEvent->type == GDK_KEY_PRESS) ? "GDK_KEY_PRESS"
+                                                  : "GDK_KEY_RELEASE"),
+           gdk_keyval_name(aGdkKeyEvent->keyval), aGdkKeyEvent->keyval,
+           aGdkKeyEvent->state, aGdkKeyEvent->hardware_keycode,
+           aGdkKeyEvent->time, GetBoolName(aGdkKeyEvent->is_modifier)));
+
+  // if we are in the middle of composing text, XIM gets to see it
+  // before mozilla does.
+  // FYI: Don't dispatch keydown event before notifying IME of the event
+  //      because IME may send a key event synchronously and consume the
+  //      original event.
+  bool IMEWasEnabled = false;
+  KeyHandlingState handlingState = KeyHandlingState::eNotHandled;
+  RefPtr<IMContextWrapper> imContext = aWindow->GetIMContext();
+  if (imContext) {
+    IMEWasEnabled = imContext->IsEnabled();
+    handlingState = imContext->OnKeyEvent(aWindow, aGdkKeyEvent);
+    if (handlingState == KeyHandlingState::eHandled) {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), the event was handled by "
+               "IMContextWrapper"));
+      return;
+    }
+  }
+
+  // work around for annoying things.
+  if (aGdkKeyEvent->keyval == GDK_Tab &&
+      AreModifiersActive(CTRL | ALT, aGdkKeyEvent->state)) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("  HandleKeyPressEvent(), didn't dispatch keyboard events "
+             "because it's Ctrl + Alt + Tab"));
+    return;
+  }
+
+  // Dispatch keydown event always.  At auto repeating, we should send
+  // KEYDOWN -> KEYPRESS -> KEYDOWN -> KEYPRESS ... -> KEYUP
+  // However, old distributions (e.g., Ubuntu 9.10) sent native key
+  // release event, so, on such platform, the DOM events will be:
+  // KEYDOWN -> KEYPRESS -> KEYUP -> KEYDOWN -> KEYPRESS -> KEYUP...
+
+  bool isKeyDownCancelled = false;
+  if (handlingState == KeyHandlingState::eNotHandled) {
+    if (DispatchKeyDownOrKeyUpEvent(aWindow, aGdkKeyEvent, false,
+                                    &isKeyDownCancelled) &&
+        (MOZ_UNLIKELY(aWindow->IsDestroyed()) || isKeyDownCancelled)) {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), dispatched eKeyDown event and "
+               "stopped handling the event because %s",
+               aWindow->IsDestroyed() ? "the window has been destroyed"
+                                      : "the event was consumed"));
+      return;
+    }
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("  HandleKeyPressEvent(), dispatched eKeyDown event and "
+             "it wasn't consumed"));
+    handlingState = KeyHandlingState::eNotHandledButEventDispatched;
+  }
+
+  // If a keydown event handler causes to enable IME, i.e., it moves
+  // focus from IME unusable content to IME usable editor, we should
+  // send the native key event to IME for the first input on the editor.
+  imContext = aWindow->GetIMContext();
+  if (!IMEWasEnabled && imContext && imContext->IsEnabled()) {
+    // Notice our keydown event was already dispatched.  This prevents
+    // unnecessary DOM keydown event in the editor.
+    handlingState = imContext->OnKeyEvent(aWindow, aGdkKeyEvent, true);
+    if (handlingState == KeyHandlingState::eHandled) {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), the event was handled by "
+               "IMContextWrapper which was enabled by the preceding eKeyDown "
+               "event"));
+      return;
+    }
+  }
+
+  // Look for specialized app-command keys
+  switch (aGdkKeyEvent->keyval) {
+    case GDK_Back:
+      aWindow->DispatchCommandEvent(nsGkAtoms::Back);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), dispatched \"Back\" command event"));
+      return;
+    case GDK_Forward:
+      aWindow->DispatchCommandEvent(nsGkAtoms::Forward);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), dispatched \"Forward\" command "
+               "event"));
+      return;
+    case GDK_Reload:
+    case GDK_Refresh:
+      aWindow->DispatchCommandEvent(nsGkAtoms::Reload);
+      return;
+    case GDK_Stop:
+      aWindow->DispatchCommandEvent(nsGkAtoms::Stop);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), dispatched \"Stop\" command event"));
+      return;
+    case GDK_Search:
+      aWindow->DispatchCommandEvent(nsGkAtoms::Search);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), dispatched \"Search\" command event"));
+      return;
+    case GDK_Favorites:
+      aWindow->DispatchCommandEvent(nsGkAtoms::Bookmarks);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), dispatched \"Bookmarks\" command "
+               "event"));
+      return;
+    case GDK_HomePage:
+      aWindow->DispatchCommandEvent(nsGkAtoms::Home);
+      return;
+    case GDK_Copy:
+    case GDK_F16:  // F16, F20, F18, F14 are old keysyms for Copy Cut Paste Undo
+      aWindow->DispatchContentCommandEvent(eContentCommandCopy);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), dispatched \"Copy\" content command "
+               "event"));
+      return;
+    case GDK_Cut:
+    case GDK_F20:
+      aWindow->DispatchContentCommandEvent(eContentCommandCut);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), dispatched \"Cut\" content command "
+               "event"));
+      return;
+    case GDK_Paste:
+    case GDK_F18:
+      aWindow->DispatchContentCommandEvent(eContentCommandPaste);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), dispatched \"Paste\" content command "
+               "event"));
+      return;
+    case GDK_Redo:
+      aWindow->DispatchContentCommandEvent(eContentCommandRedo);
+      return;
+    case GDK_Undo:
+    case GDK_F14:
+      aWindow->DispatchContentCommandEvent(eContentCommandUndo);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), dispatched \"Undo\" content command "
+               "event"));
+      return;
+    default:
+      break;
+  }
+
+  // before we dispatch a key, check if it's the context menu key.
+  // If so, send a context menu key event instead.
+  if (MaybeDispatchContextMenuEvent(aWindow, aGdkKeyEvent)) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("  HandleKeyPressEvent(), stopped dispatching eKeyPress event "
+             "because eContextMenu event was dispatched"));
+    return;
+  }
+
+  RefPtr<TextEventDispatcher> textEventDispatcher =
+      aWindow->GetTextEventDispatcher();
+  nsresult rv = textEventDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gKeyLog, LogLevel::Error,
+            ("  HandleKeyPressEvent(), stopped dispatching eKeyPress event "
+             "because of failed to initialize TextEventDispatcher"));
+    return;
+  }
+
+  // If the character code is in the BMP, send the key press event.
+  // Otherwise, send a compositionchange event with the equivalent UTF-16
+  // string.
+  // TODO: Investigate other browser's behavior in this case because
+  //       this hack is odd for UI Events.
+  WidgetKeyboardEvent keypressEvent(true, eKeyPress, aWindow);
+  KeymapWrapper::InitKeyEvent(keypressEvent, aGdkKeyEvent, false);
+  nsEventStatus status = nsEventStatus_eIgnore;
+  if (keypressEvent.mKeyNameIndex != KEY_NAME_INDEX_USE_STRING ||
+      keypressEvent.mKeyValue.Length() == 1) {
+    if (textEventDispatcher->MaybeDispatchKeypressEvents(keypressEvent, status,
+                                                         aGdkKeyEvent)) {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), dispatched eKeyPress event "
+               "(status=%s)",
+               GetStatusName(status)));
+    } else {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyPressEvent(), didn't dispatch eKeyPress event "
+               "(status=%s)",
+               GetStatusName(status)));
+    }
+  } else {
+    WidgetEventTime eventTime = aWindow->GetWidgetEventTime(aGdkKeyEvent->time);
+    textEventDispatcher->CommitComposition(status, &keypressEvent.mKeyValue,
+                                           &eventTime);
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("  HandleKeyPressEvent(), dispatched a set of composition "
+             "events"));
+  }
+}
+
+/* static */
+bool KeymapWrapper::HandleKeyReleaseEvent(nsWindow* aWindow,
+                                          GdkEventKey* aGdkKeyEvent) {
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("HandleKeyReleaseEvent(aWindow=%p, aGdkKeyEvent={ type=%s, "
+           "keyval=%s(0x%X), state=0x%08X, hardware_keycode=0x%08X, "
+           "time=%u, is_modifier=%s })",
+           aWindow,
+           ((aGdkKeyEvent->type == GDK_KEY_PRESS) ? "GDK_KEY_PRESS"
+                                                  : "GDK_KEY_RELEASE"),
+           gdk_keyval_name(aGdkKeyEvent->keyval), aGdkKeyEvent->keyval,
+           aGdkKeyEvent->state, aGdkKeyEvent->hardware_keycode,
+           aGdkKeyEvent->time, GetBoolName(aGdkKeyEvent->is_modifier)));
+
+  RefPtr<IMContextWrapper> imContext = aWindow->GetIMContext();
+  if (imContext) {
+    KeyHandlingState handlingState =
+        imContext->OnKeyEvent(aWindow, aGdkKeyEvent);
+    if (handlingState != KeyHandlingState::eNotHandled) {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("  HandleKeyReleaseEvent(), the event was handled by "
+               "IMContextWrapper"));
+      return true;
+    }
+  }
+
+  bool isCancelled = false;
+  if (NS_WARN_IF(!DispatchKeyDownOrKeyUpEvent(aWindow, aGdkKeyEvent, false,
+                                              &isCancelled))) {
+    MOZ_LOG(gKeyLog, LogLevel::Error,
+            ("  HandleKeyReleaseEvent(), didn't dispatch eKeyUp event"));
+    return false;
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("  HandleKeyReleaseEvent(), dispatched eKeyUp event "
+           "(isCancelled=%s)",
+           GetBoolName(isCancelled)));
+  return true;
+}
+
+guint KeymapWrapper::GetModifierState(GdkEventKey* aGdkKeyEvent,
+                                      KeymapWrapper* aWrapper) {
+  guint state = aGdkKeyEvent->state;
+  if (!aGdkKeyEvent->is_modifier) {
+    return state;
+  }
+#ifdef MOZ_X11
+  // NOTE: The state of given key event indicates adjacent state of
+  // modifier keys.  E.g., even if the event is Shift key press event,
+  // the bit for Shift is still false.  By the same token, even if the
+  // event is Shift key release event, the bit for Shift is still true.
+  // Unfortunately, gdk_keyboard_get_modifiers() returns current modifier
+  // state.  It means if there're some pending modifier key press or
+  // key release events, the result isn't what we want.
+  GdkDisplay* gdkDisplay = gdk_display_get_default();
+  if (GdkIsX11Display(gdkDisplay)) {
+    GdkDisplay* gdkDisplay = gdk_display_get_default();
+    Display* display = gdk_x11_display_get_xdisplay(gdkDisplay);
+    if (XEventsQueued(display, QueuedAfterReading)) {
+      XEvent nextEvent;
+      XPeekEvent(display, &nextEvent);
+      if (nextEvent.type == aWrapper->mXKBBaseEventCode) {
+        XkbEvent* XKBEvent = (XkbEvent*)&nextEvent;
+        if (XKBEvent->any.xkb_type == XkbStateNotify) {
+          XkbStateNotifyEvent* stateNotifyEvent =
+              (XkbStateNotifyEvent*)XKBEvent;
+          state &= ~0xFF;
+          state |= stateNotifyEvent->lookup_mods;
+        }
+      }
+    }
+    return state;
+  }
+#endif
+#ifdef MOZ_WAYLAND
+  int mask = 0;
+  switch (aGdkKeyEvent->keyval) {
+    case GDK_Shift_L:
+    case GDK_Shift_R:
+      mask = aWrapper->GetGdkModifierMask(SHIFT);
+      break;
+    case GDK_Control_L:
+    case GDK_Control_R:
+      mask = aWrapper->GetGdkModifierMask(CTRL);
+      break;
+    case GDK_Alt_L:
+    case GDK_Alt_R:
+      mask = aWrapper->GetGdkModifierMask(ALT);
+      break;
+    case GDK_Super_L:
+    case GDK_Super_R:
+      mask = aWrapper->GetGdkModifierMask(SUPER);
+      break;
+    case GDK_Hyper_L:
+    case GDK_Hyper_R:
+      mask = aWrapper->GetGdkModifierMask(HYPER);
+      break;
+    case GDK_Meta_L:
+    case GDK_Meta_R:
+      mask = aWrapper->GetGdkModifierMask(META);
+      break;
+    default:
+      break;
+  }
+  if (aGdkKeyEvent->type == GDK_KEY_PRESS) {
+    state |= mask;
+  } else {
+    state &= ~mask;
+  }
+#endif
+  return state;
+}
+
+/* static */
+void KeymapWrapper::InitKeyEvent(WidgetKeyboardEvent& aKeyEvent,
+                                 GdkEventKey* aGdkKeyEvent,
+                                 bool aIsProcessedByIME) {
+  MOZ_ASSERT(
+      !aIsProcessedByIME || aKeyEvent.mMessage != eKeyPress,
+      "If the key event is handled by IME, keypress event shouldn't be fired");
+
+  KeymapWrapper* keymapWrapper = GetInstance();
+
+  aKeyEvent.mCodeNameIndex = ComputeDOMCodeNameIndex(aGdkKeyEvent);
+  MOZ_ASSERT(aKeyEvent.mCodeNameIndex != CODE_NAME_INDEX_USE_STRING);
+  aKeyEvent.mKeyNameIndex =
+      aIsProcessedByIME ? KEY_NAME_INDEX_Process
+                        : keymapWrapper->ComputeDOMKeyNameIndex(aGdkKeyEvent);
+  if (aKeyEvent.mKeyNameIndex == KEY_NAME_INDEX_Unidentified) {
+    uint32_t charCode = GetCharCodeFor(aGdkKeyEvent);
+    if (!charCode) {
+      charCode = keymapWrapper->GetUnmodifiedCharCodeFor(aGdkKeyEvent);
+    }
+    if (charCode) {
+      aKeyEvent.mKeyNameIndex = KEY_NAME_INDEX_USE_STRING;
+      MOZ_ASSERT(aKeyEvent.mKeyValue.IsEmpty(),
+                 "Uninitialized mKeyValue must be empty");
+      AppendUCS4ToUTF16(charCode, aKeyEvent.mKeyValue);
+    }
+  }
+
+  if (aIsProcessedByIME) {
+    aKeyEvent.mKeyCode = NS_VK_PROCESSKEY;
+  } else if (aKeyEvent.mKeyNameIndex != KEY_NAME_INDEX_USE_STRING ||
+             aKeyEvent.mMessage != eKeyPress) {
+    aKeyEvent.mKeyCode = ComputeDOMKeyCode(aGdkKeyEvent);
+  } else {
+    aKeyEvent.mKeyCode = 0;
+  }
+
+  const guint modifierState = GetModifierState(aGdkKeyEvent, keymapWrapper);
+  InitInputEvent(aKeyEvent, modifierState);
+
+  switch (aGdkKeyEvent->keyval) {
+    case GDK_Shift_L:
+    case GDK_Control_L:
+    case GDK_Alt_L:
+    case GDK_Super_L:
+    case GDK_Hyper_L:
+    case GDK_Meta_L:
+      aKeyEvent.mLocation = eKeyLocationLeft;
+      break;
+
+    case GDK_Shift_R:
+    case GDK_Control_R:
+    case GDK_Alt_R:
+    case GDK_Super_R:
+    case GDK_Hyper_R:
+    case GDK_Meta_R:
+      aKeyEvent.mLocation = eKeyLocationRight;
+      break;
+
+    case GDK_KP_0:
+    case GDK_KP_1:
+    case GDK_KP_2:
+    case GDK_KP_3:
+    case GDK_KP_4:
+    case GDK_KP_5:
+    case GDK_KP_6:
+    case GDK_KP_7:
+    case GDK_KP_8:
+    case GDK_KP_9:
+    case GDK_KP_Space:
+    case GDK_KP_Tab:
+    case GDK_KP_Enter:
+    case GDK_KP_F1:
+    case GDK_KP_F2:
+    case GDK_KP_F3:
+    case GDK_KP_F4:
+    case GDK_KP_Home:
+    case GDK_KP_Left:
+    case GDK_KP_Up:
+    case GDK_KP_Right:
+    case GDK_KP_Down:
+    case GDK_KP_Prior:  // same as GDK_KP_Page_Up
+    case GDK_KP_Next:   // same as GDK_KP_Page_Down
+    case GDK_KP_End:
+    case GDK_KP_Begin:
+    case GDK_KP_Insert:
+    case GDK_KP_Delete:
+    case GDK_KP_Equal:
+    case GDK_KP_Multiply:
+    case GDK_KP_Add:
+    case GDK_KP_Separator:
+    case GDK_KP_Subtract:
+    case GDK_KP_Decimal:
+    case GDK_KP_Divide:
+      aKeyEvent.mLocation = eKeyLocationNumpad;
+      break;
+
+    default:
+      aKeyEvent.mLocation = eKeyLocationStandard;
+      break;
+  }
+
+  // The transformations above and in gdk for the keyval are not invertible
+  // so link to the GdkEvent (which will vanish soon after return from the
+  // event callback) to give plugins access to hardware_keycode and state.
+  // (An XEvent would be nice but the GdkEvent is good enough.)
+  aKeyEvent.mNativeKeyEvent = static_cast<void*>(aGdkKeyEvent);
+  aKeyEvent.mIsRepeat =
+      sRepeatState == REPEATING &&
+      aGdkKeyEvent->hardware_keycode == sLastRepeatableHardwareKeyCode;
+
+  MOZ_LOG(
+      gKeyLog, LogLevel::Info,
+      ("%p InitKeyEvent, modifierState=0x%08X "
+       "aKeyEvent={ mMessage=%s, isShift=%s, isControl=%s, "
+       "isAlt=%s, isMeta=%s , mKeyCode=0x%02X, mCharCode=%s, "
+       "mKeyNameIndex=%s, mKeyValue=%s, mCodeNameIndex=%s, mCodeValue=%s, "
+       "mLocation=%s, mIsRepeat=%s }",
+       keymapWrapper, modifierState, ToChar(aKeyEvent.mMessage),
+       GetBoolName(aKeyEvent.IsShift()), GetBoolName(aKeyEvent.IsControl()),
+       GetBoolName(aKeyEvent.IsAlt()), GetBoolName(aKeyEvent.IsMeta()),
+       aKeyEvent.mKeyCode,
+       GetCharacterCodeName(static_cast<char16_t>(aKeyEvent.mCharCode)).get(),
+       ToString(aKeyEvent.mKeyNameIndex).get(),
+       GetCharacterCodeNames(aKeyEvent.mKeyValue).get(),
+       ToString(aKeyEvent.mCodeNameIndex).get(),
+       GetCharacterCodeNames(aKeyEvent.mCodeValue).get(),
+       GetKeyLocationName(aKeyEvent.mLocation).get(),
+       GetBoolName(aKeyEvent.mIsRepeat)));
+}
+
+/* static */
+uint32_t KeymapWrapper::GetCharCodeFor(const GdkEventKey* aGdkKeyEvent) {
+  // Anything above 0xf000 is considered a non-printable
+  // Exception: directly encoded UCS characters
+  if (aGdkKeyEvent->keyval > 0xf000 &&
+      (aGdkKeyEvent->keyval & 0xff000000) != 0x01000000) {
+    // Keypad keys are an exception: they return a value different
+    // from their non-keypad equivalents, but mozilla doesn't distinguish.
+    switch (aGdkKeyEvent->keyval) {
+      case GDK_KP_Space:
+        return ' ';
+      case GDK_KP_Equal:
+        return '=';
+      case GDK_KP_Multiply:
+        return '*';
+      case GDK_KP_Add:
+        return '+';
+      case GDK_KP_Separator:
+        return ',';
+      case GDK_KP_Subtract:
+        return '-';
+      case GDK_KP_Decimal:
+        return '.';
+      case GDK_KP_Divide:
+        return '/';
+      case GDK_KP_0:
+        return '0';
+      case GDK_KP_1:
+        return '1';
+      case GDK_KP_2:
+        return '2';
+      case GDK_KP_3:
+        return '3';
+      case GDK_KP_4:
+        return '4';
+      case GDK_KP_5:
+        return '5';
+      case GDK_KP_6:
+        return '6';
+      case GDK_KP_7:
+        return '7';
+      case GDK_KP_8:
+        return '8';
+      case GDK_KP_9:
+        return '9';
+      default:
+        return 0;  // non-printables
+    }
+  }
+
+  static const long MAX_UNICODE = 0x10FFFF;
+
+  // we're supposedly printable, let's try to convert
+  long ucs = keysym2ucs(aGdkKeyEvent->keyval);
+  if ((ucs != -1) && (ucs < MAX_UNICODE)) {
+    return ucs;
+  }
+
+  // I guess we couldn't convert
+  return 0;
+}
+
+uint32_t KeymapWrapper::GetCharCodeFor(const GdkEventKey* aGdkKeyEvent,
+                                       guint aGdkModifierState, gint aGroup) {
+  guint keyval;
+  if (!gdk_keymap_translate_keyboard_state(
+          mGdkKeymap, aGdkKeyEvent->hardware_keycode,
+          GdkModifierType(aGdkModifierState), aGroup, &keyval, nullptr, nullptr,
+          nullptr)) {
+    return 0;
+  }
+  GdkEventKey tmpEvent = *aGdkKeyEvent;
+  tmpEvent.state = aGdkModifierState;
+  tmpEvent.keyval = keyval;
+  tmpEvent.group = aGroup;
+  return GetCharCodeFor(&tmpEvent);
+}
+
+uint32_t KeymapWrapper::GetUnmodifiedCharCodeFor(
+    const GdkEventKey* aGdkKeyEvent) {
+  guint state =
+      aGdkKeyEvent->state &
+      (GetGdkModifierMask(SHIFT) | GetGdkModifierMask(CAPS_LOCK) |
+       GetGdkModifierMask(NUM_LOCK) | GetGdkModifierMask(SCROLL_LOCK) |
+       GetGdkModifierMask(LEVEL3) | GetGdkModifierMask(LEVEL5));
+  uint32_t charCode =
+      GetCharCodeFor(aGdkKeyEvent, GdkModifierType(state), aGdkKeyEvent->group);
+  if (charCode) {
+    return charCode;
+  }
+  // If no character is mapped to the key when Level3 Shift or Level5 Shift
+  // is active, let's return a character which is inputted by the key without
+  // Level3 nor Level5 Shift.
+  guint stateWithoutAltGraph =
+      state & ~(GetGdkModifierMask(LEVEL3) | GetGdkModifierMask(LEVEL5));
+  if (state == stateWithoutAltGraph) {
+    return 0;
+  }
+  return GetCharCodeFor(aGdkKeyEvent, GdkModifierType(stateWithoutAltGraph),
+                        aGdkKeyEvent->group);
+}
+
+gint KeymapWrapper::GetKeyLevel(GdkEventKey* aGdkKeyEvent) {
+  gint level;
+  if (!gdk_keymap_translate_keyboard_state(
+          mGdkKeymap, aGdkKeyEvent->hardware_keycode,
+          GdkModifierType(aGdkKeyEvent->state), aGdkKeyEvent->group, nullptr,
+          nullptr, &level, nullptr)) {
+    return -1;
+  }
+  return level;
+}
+
+gint KeymapWrapper::GetFirstLatinGroup() {
+  GdkKeymapKey* keys;
+  gint count;
+  gint minGroup = -1;
+  if (gdk_keymap_get_entries_for_keyval(mGdkKeymap, GDK_a, &keys, &count)) {
+    // find the minimum number group for latin inputtable layout
+    for (gint i = 0; i < count && minGroup != 0; ++i) {
+      if (keys[i].level != 0 && keys[i].level != 1) {
+        continue;
+      }
+      if (minGroup >= 0 && keys[i].group > minGroup) {
+        continue;
+      }
+      minGroup = keys[i].group;
+    }
+    g_free(keys);
+  }
+  return minGroup;
+}
+
+bool KeymapWrapper::IsLatinGroup(guint8 aGroup) {
+  GdkKeymapKey* keys;
+  gint count;
+  bool result = false;
+  if (gdk_keymap_get_entries_for_keyval(mGdkKeymap, GDK_a, &keys, &count)) {
+    for (gint i = 0; i < count; ++i) {
+      if (keys[i].level != 0 && keys[i].level != 1) {
+        continue;
+      }
+      if (keys[i].group == aGroup) {
+        result = true;
+        break;
+      }
+    }
+    g_free(keys);
+  }
+  return result;
+}
+
+bool KeymapWrapper::IsAutoRepeatableKey(guint aHardwareKeyCode) {
+#ifdef MOZ_X11
+  uint8_t indexOfArray = aHardwareKeyCode / 8;
+  MOZ_ASSERT(indexOfArray < ArrayLength(mKeyboardState.auto_repeats),
+             "invalid index");
+  char bitMask = 1 << (aHardwareKeyCode % 8);
+  return (mKeyboardState.auto_repeats[indexOfArray] & bitMask) != 0;
+#else
+  return false;
+#endif
+}
+
+/* static */
+bool KeymapWrapper::IsBasicLatinLetterOrNumeral(uint32_t aCharCode) {
+  return (aCharCode >= 'a' && aCharCode <= 'z') ||
+         (aCharCode >= 'A' && aCharCode <= 'Z') ||
+         (aCharCode >= '0' && aCharCode <= '9');
+}
+
+/* static */
+guint KeymapWrapper::GetGDKKeyvalWithoutModifier(
+    const GdkEventKey* aGdkKeyEvent) {
+  KeymapWrapper* keymapWrapper = GetInstance();
+  guint state =
+      (aGdkKeyEvent->state & keymapWrapper->GetGdkModifierMask(NUM_LOCK));
+  guint keyval;
+  if (!gdk_keymap_translate_keyboard_state(
+          keymapWrapper->mGdkKeymap, aGdkKeyEvent->hardware_keycode,
+          GdkModifierType(state), aGdkKeyEvent->group, &keyval, nullptr,
+          nullptr, nullptr)) {
+    return 0;
+  }
+  return keyval;
+}
+
+/* static */
+uint32_t KeymapWrapper::GetDOMKeyCodeFromKeyPairs(guint aGdkKeyval) {
+  switch (aGdkKeyval) {
+    case GDK_Cancel:
+      return NS_VK_CANCEL;
+    case GDK_BackSpace:
+      return NS_VK_BACK;
+    case GDK_Tab:
+    case GDK_ISO_Left_Tab:
+      return NS_VK_TAB;
+    case GDK_Clear:
+      return NS_VK_CLEAR;
+    case GDK_Return:
+      return NS_VK_RETURN;
+    case GDK_Shift_L:
+    case GDK_Shift_R:
+    case GDK_Shift_Lock:
+      return NS_VK_SHIFT;
+    case GDK_Control_L:
+    case GDK_Control_R:
+      return NS_VK_CONTROL;
+    case GDK_Alt_L:
+    case GDK_Alt_R:
+      return NS_VK_ALT;
+    case GDK_Meta_L:
+    case GDK_Meta_R:
+      return NS_VK_META;
+
+    // Assume that Super or Hyper is always mapped to physical Win key.
+    case GDK_Super_L:
+    case GDK_Super_R:
+    case GDK_Hyper_L:
+    case GDK_Hyper_R:
+      return NS_VK_WIN;
+
+    // GTK's AltGraph key is similar to Mac's Option (Alt) key.  However,
+    // unfortunately, browsers on Mac are using NS_VK_ALT for it even though
+    // it's really different from Alt key on Windows.
+    // On the other hand, GTK's AltGrapsh keys are really different from
+    // Alt key.  However, there is no AltGrapsh key on Windows.  On Windows,
+    // both Ctrl and Alt keys are pressed internally when AltGr key is
+    // pressed.  For some languages' users, AltGraph key is important, so,
+    // web applications on such locale may want to know AltGraph key press.
+    // Therefore, we should map AltGr keycode for them only on GTK.
+    case GDK_ISO_Level3_Shift:
+    case GDK_ISO_Level5_Shift:
+    // We assume that Mode_switch is always used for level3 shift.
+    case GDK_Mode_switch:
+      return NS_VK_ALTGR;
+
+    case GDK_Pause:
+      return NS_VK_PAUSE;
+    case GDK_Caps_Lock:
+      return NS_VK_CAPS_LOCK;
+    case GDK_Kana_Lock:
+    case GDK_Kana_Shift:
+      return NS_VK_KANA;
+    case GDK_Hangul:
+      return NS_VK_HANGUL;
+    // case GDK_XXX:                   return NS_VK_JUNJA;
+    // case GDK_XXX:                   return NS_VK_FINAL;
+    case GDK_Hangul_Hanja:
+      return NS_VK_HANJA;
+    case GDK_Kanji:
+      return NS_VK_KANJI;
+    case GDK_Escape:
+      return NS_VK_ESCAPE;
+    case GDK_Henkan:
+      return NS_VK_CONVERT;
+    case GDK_Muhenkan:
+      return NS_VK_NONCONVERT;
+    // case GDK_XXX:                   return NS_VK_ACCEPT;
+    // case GDK_XXX:                   return NS_VK_MODECHANGE;
+    case GDK_Page_Up:
+      return NS_VK_PAGE_UP;
+    case GDK_Page_Down:
+      return NS_VK_PAGE_DOWN;
+    case GDK_End:
+      return NS_VK_END;
+    case GDK_Home:
+      return NS_VK_HOME;
+    case GDK_Left:
+      return NS_VK_LEFT;
+    case GDK_Up:
+      return NS_VK_UP;
+    case GDK_Right:
+      return NS_VK_RIGHT;
+    case GDK_Down:
+      return NS_VK_DOWN;
+    case GDK_Select:
+      return NS_VK_SELECT;
+    case GDK_Print:
+      return NS_VK_PRINT;
+    case GDK_Execute:
+      return NS_VK_EXECUTE;
+    case GDK_Insert:
+      return NS_VK_INSERT;
+    case GDK_Delete:
+      return NS_VK_DELETE;
+    case GDK_Help:
+      return NS_VK_HELP;
+
+    // keypad keys
+    case GDK_KP_Left:
+      return NS_VK_LEFT;
+    case GDK_KP_Right:
+      return NS_VK_RIGHT;
+    case GDK_KP_Up:
+      return NS_VK_UP;
+    case GDK_KP_Down:
+      return NS_VK_DOWN;
+    case GDK_KP_Page_Up:
+      return NS_VK_PAGE_UP;
+    // Not sure what these are
+    // case GDK_KP_Prior:              return NS_VK_;
+    // case GDK_KP_Next:               return NS_VK_;
+    case GDK_KP_Begin:
+      return NS_VK_CLEAR;  // Num-unlocked 5
+    case GDK_KP_Page_Down:
+      return NS_VK_PAGE_DOWN;
+    case GDK_KP_Home:
+      return NS_VK_HOME;
+    case GDK_KP_End:
+      return NS_VK_END;
+    case GDK_KP_Insert:
+      return NS_VK_INSERT;
+    case GDK_KP_Delete:
+      return NS_VK_DELETE;
+    case GDK_KP_Enter:
+      return NS_VK_RETURN;
+
+    case GDK_Num_Lock:
+      return NS_VK_NUM_LOCK;
+    case GDK_Scroll_Lock:
+      return NS_VK_SCROLL_LOCK;
+
+    // Function keys
+    case GDK_F1:
+      return NS_VK_F1;
+    case GDK_F2:
+      return NS_VK_F2;
+    case GDK_F3:
+      return NS_VK_F3;
+    case GDK_F4:
+      return NS_VK_F4;
+    case GDK_F5:
+      return NS_VK_F5;
+    case GDK_F6:
+      return NS_VK_F6;
+    case GDK_F7:
+      return NS_VK_F7;
+    case GDK_F8:
+      return NS_VK_F8;
+    case GDK_F9:
+      return NS_VK_F9;
+    case GDK_F10:
+      return NS_VK_F10;
+    case GDK_F11:
+      return NS_VK_F11;
+    case GDK_F12:
+      return NS_VK_F12;
+    case GDK_F13:
+      return NS_VK_F13;
+    case GDK_F14:
+      return NS_VK_F14;
+    case GDK_F15:
+      return NS_VK_F15;
+    case GDK_F16:
+      return NS_VK_F16;
+    case GDK_F17:
+      return NS_VK_F17;
+    case GDK_F18:
+      return NS_VK_F18;
+    case GDK_F19:
+      return NS_VK_F19;
+    case GDK_F20:
+      return NS_VK_F20;
+    case GDK_F21:
+      return NS_VK_F21;
+    case GDK_F22:
+      return NS_VK_F22;
+    case GDK_F23:
+      return NS_VK_F23;
+    case GDK_F24:
+      return NS_VK_F24;
+
+    // context menu key, keysym 0xff67, typically keycode 117 on 105-key
+    // (Microsoft) x86 keyboards, located between right 'Windows' key and
+    // right Ctrl key
+    case GDK_Menu:
+      return NS_VK_CONTEXT_MENU;
+    case GDK_Sleep:
+      return NS_VK_SLEEP;
+
+    case GDK_3270_Attn:
+      return NS_VK_ATTN;
+    case GDK_3270_CursorSelect:
+      return NS_VK_CRSEL;
+    case GDK_3270_ExSelect:
+      return NS_VK_EXSEL;
+    case GDK_3270_EraseEOF:
+      return NS_VK_EREOF;
+    case GDK_3270_Play:
+      return NS_VK_PLAY;
+    // case GDK_XXX:                   return NS_VK_ZOOM;
+    case GDK_3270_PA1:
+      return NS_VK_PA1;
+
+    // map Sun Keyboard special keysyms on to NS_VK keys
+
+    // Sun F11 key generates SunF36(0x1005ff10) keysym
+    case 0x1005ff10:
+      return NS_VK_F11;
+    // Sun F12 key generates SunF37(0x1005ff11) keysym
+    case 0x1005ff11:
+      return NS_VK_F12;
+    default:
+      return 0;
+  }
+}
+
+void KeymapWrapper::WillDispatchKeyboardEvent(WidgetKeyboardEvent& aKeyEvent,
+                                              GdkEventKey* aGdkKeyEvent) {
+  GetInstance()->WillDispatchKeyboardEventInternal(aKeyEvent, aGdkKeyEvent);
+}
+
+void KeymapWrapper::WillDispatchKeyboardEventInternal(
+    WidgetKeyboardEvent& aKeyEvent, GdkEventKey* aGdkKeyEvent) {
+  if (!aGdkKeyEvent) {
+    // If aGdkKeyEvent is nullptr, we're trying to dispatch a fake keyboard
+    // event in such case, we don't need to set alternative char codes.
+    // So, we don't need to do nothing here.  This case is typically we're
+    // dispatching eKeyDown or eKeyUp event during composition.
+    return;
+  }
+
+  uint32_t charCode = GetCharCodeFor(aGdkKeyEvent);
+  if (!charCode) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p WillDispatchKeyboardEventInternal, "
+             "mKeyCode=0x%02X, charCode=0x%08X",
+             this, aKeyEvent.mKeyCode, aKeyEvent.mCharCode));
+    return;
+  }
+
+  // The mCharCode was set from mKeyValue. However, for example, when Ctrl key
+  // is pressed, its value should indicate an ASCII character for backward
+  // compatibility rather than inputting character without the modifiers.
+  // Therefore, we need to modify mCharCode value here.
+  aKeyEvent.SetCharCode(charCode);
+
+  gint level = GetKeyLevel(aGdkKeyEvent);
+  if (level != 0 && level != 1) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p WillDispatchKeyboardEventInternal, "
+             "mKeyCode=0x%02X, mCharCode=0x%08X, level=%d",
+             this, aKeyEvent.mKeyCode, aKeyEvent.mCharCode, level));
+    return;
+  }
+
+  guint baseState = aGdkKeyEvent->state &
+                    ~(GetGdkModifierMask(SHIFT) | GetGdkModifierMask(CTRL) |
+                      GetGdkModifierMask(ALT) | GetGdkModifierMask(META) |
+                      GetGdkModifierMask(SUPER) | GetGdkModifierMask(HYPER));
+
+  // We shold send both shifted char and unshifted char, all keyboard layout
+  // users can use all keys.  Don't change event.mCharCode. On some keyboard
+  // layouts, Ctrl/Alt/Meta keys are used for inputting some characters.
+  AlternativeCharCode altCharCodes(0, 0);
+  // unshifted charcode of current keyboard layout.
+  altCharCodes.mUnshiftedCharCode =
+      GetCharCodeFor(aGdkKeyEvent, baseState, aGdkKeyEvent->group);
+  bool isLatin = (altCharCodes.mUnshiftedCharCode <= 0xFF);
+  // shifted charcode of current keyboard layout.
+  altCharCodes.mShiftedCharCode = GetCharCodeFor(
+      aGdkKeyEvent, baseState | GetGdkModifierMask(SHIFT), aGdkKeyEvent->group);
+  isLatin = isLatin && (altCharCodes.mShiftedCharCode <= 0xFF);
+  if (altCharCodes.mUnshiftedCharCode || altCharCodes.mShiftedCharCode) {
+    aKeyEvent.mAlternativeCharCodes.AppendElement(altCharCodes);
+  }
+
+  bool needLatinKeyCodes = !isLatin;
+  if (!needLatinKeyCodes) {
+    needLatinKeyCodes =
+        (IS_ASCII_ALPHABETICAL(altCharCodes.mUnshiftedCharCode) !=
+         IS_ASCII_ALPHABETICAL(altCharCodes.mShiftedCharCode));
+  }
+
+  // If current keyboard layout can input Latin characters, we don't need
+  // more information.
+  if (!needLatinKeyCodes) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p WillDispatchKeyboardEventInternal, "
+             "mKeyCode=0x%02X, mCharCode=0x%08X, level=%d, altCharCodes={ "
+             "mUnshiftedCharCode=0x%08X, mShiftedCharCode=0x%08X }",
+             this, aKeyEvent.mKeyCode, aKeyEvent.mCharCode, level,
+             altCharCodes.mUnshiftedCharCode, altCharCodes.mShiftedCharCode));
+    return;
+  }
+
+  // Next, find Latin inputtable keyboard layout.
+  gint minGroup = GetFirstLatinGroup();
+  if (minGroup < 0) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p WillDispatchKeyboardEventInternal, "
+             "Latin keyboard layout isn't found: "
+             "mKeyCode=0x%02X, mCharCode=0x%08X, level=%d, "
+             "altCharCodes={ mUnshiftedCharCode=0x%08X, "
+             "mShiftedCharCode=0x%08X }",
+             this, aKeyEvent.mKeyCode, aKeyEvent.mCharCode, level,
+             altCharCodes.mUnshiftedCharCode, altCharCodes.mShiftedCharCode));
+    return;
+  }
+
+  AlternativeCharCode altLatinCharCodes(0, 0);
+  uint32_t unmodifiedCh = aKeyEvent.IsShift() ? altCharCodes.mShiftedCharCode
+                                              : altCharCodes.mUnshiftedCharCode;
+
+  // unshifted charcode of found keyboard layout.
+  uint32_t ch = GetCharCodeFor(aGdkKeyEvent, baseState, minGroup);
+  altLatinCharCodes.mUnshiftedCharCode =
+      IsBasicLatinLetterOrNumeral(ch) ? ch : 0;
+  // shifted charcode of found keyboard layout.
+  ch = GetCharCodeFor(aGdkKeyEvent, baseState | GetGdkModifierMask(SHIFT),
+                      minGroup);
+  altLatinCharCodes.mShiftedCharCode = IsBasicLatinLetterOrNumeral(ch) ? ch : 0;
+  if (altLatinCharCodes.mUnshiftedCharCode ||
+      altLatinCharCodes.mShiftedCharCode) {
+    aKeyEvent.mAlternativeCharCodes.AppendElement(altLatinCharCodes);
+  }
+  // If the mCharCode is not Latin, and the level is 0 or 1, we should
+  // replace the mCharCode to Latin char if Alt keys are not pressed. (Alt
+  // should be sent the localized char for accesskey like handling of Web
+  // Applications.)
+  ch = aKeyEvent.IsShift() ? altLatinCharCodes.mShiftedCharCode
+                           : altLatinCharCodes.mUnshiftedCharCode;
+  if (ch && !aKeyEvent.IsAlt() && charCode == unmodifiedCh) {
+    aKeyEvent.SetCharCode(ch);
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p WillDispatchKeyboardEventInternal, "
+           "mKeyCode=0x%02X, mCharCode=0x%08X, level=%d, minGroup=%d, "
+           "altCharCodes={ mUnshiftedCharCode=0x%08X, "
+           "mShiftedCharCode=0x%08X } "
+           "altLatinCharCodes={ mUnshiftedCharCode=0x%08X, "
+           "mShiftedCharCode=0x%08X }",
+           this, aKeyEvent.mKeyCode, aKeyEvent.mCharCode, level, minGroup,
+           altCharCodes.mUnshiftedCharCode, altCharCodes.mShiftedCharCode,
+           altLatinCharCodes.mUnshiftedCharCode,
+           altLatinCharCodes.mShiftedCharCode));
+}
+
+#ifdef MOZ_WAYLAND
+void KeymapWrapper::SetFocusIn(wl_surface* aFocusSurface,
+                               uint32_t aFocusSerial) {
+  LOGW("KeymapWrapper::SetFocusIn() surface %p ID %d serial %d", aFocusSurface,
+       aFocusSurface ? wl_proxy_get_id((struct wl_proxy*)aFocusSurface) : 0,
+       aFocusSerial);
+
+  KeymapWrapper* keymapWrapper = KeymapWrapper::GetInstance();
+  keymapWrapper->mFocusSurface = aFocusSurface;
+  keymapWrapper->mFocusSerial = aFocusSerial;
+}
+
+// aFocusSurface can be null in case that focused surface is already destroyed.
+void KeymapWrapper::SetFocusOut(wl_surface* aFocusSurface) {
+  KeymapWrapper* keymapWrapper = KeymapWrapper::GetInstance();
+  LOGW("KeymapWrapper::SetFocusOut surface %p ID %d", aFocusSurface,
+       aFocusSurface ? wl_proxy_get_id((struct wl_proxy*)aFocusSurface) : 0);
+
+  keymapWrapper->mFocusSurface = nullptr;
+  keymapWrapper->mFocusSerial = 0;
+}
+
+void KeymapWrapper::GetFocusInfo(wl_surface** aFocusSurface,
+                                 uint32_t* aFocusSerial) {
+  KeymapWrapper* keymapWrapper = KeymapWrapper::GetInstance();
+  *aFocusSurface = keymapWrapper->mFocusSurface;
+  *aFocusSerial = keymapWrapper->mFocusSerial;
+}
+
+void KeymapWrapper::SetSeat(wl_seat* aSeat, int aId) {
+  sSeat = aSeat;
+  sSeatID = aId;
+  wl_seat_add_listener(aSeat, &seat_listener, nullptr);
+}
+
+void KeymapWrapper::ClearSeat(int aId) {
+  if (sSeatID == aId) {
+    ClearKeyboard();
+    sSeat = nullptr;
+    sSeatID = -1;
+  }
+}
+
+wl_seat* KeymapWrapper::GetSeat() { return sSeat; }
+
+void KeymapWrapper::SetKeyboard(wl_keyboard* aKeyboard) {
+  sKeyboard = aKeyboard;
+}
+
+wl_keyboard* KeymapWrapper::GetKeyboard() { return sKeyboard; }
+
+void KeymapWrapper::ClearKeyboard() {
+  if (sKeyboard) {
+    wl_keyboard_destroy(sKeyboard);
+    sKeyboard = nullptr;
+  }
+}
+#endif
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/gtk/nsGtkKeyUtils.h b/widget/gtk/nsGtkKeyUtils.h
new file mode 100644
index 0000000000..aac9d446f3
--- /dev/null
+++ b/widget/gtk/nsGtkKeyUtils.h
@@ -0,0 +1,509 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsGdkKeyUtils_h__
+#define __nsGdkKeyUtils_h__
+
+#include "mozilla/EventForwards.h"
+#include "nsIWidget.h"
+#include "nsTArray.h"
+
+#include <gdk/gdk.h>
+#ifdef MOZ_X11
+#  include <X11/XKBlib.h>
+#endif
+#ifdef MOZ_WAYLAND
+#  include <gdk/gdkwayland.h>
+#  include <xkbcommon/xkbcommon.h>
+#endif
+#include "X11UndefineNone.h"
+
+class nsWindow;
+
+namespace mozilla {
+namespace widget {
+
+/**
+ *  KeymapWrapper is a wrapper class of GdkKeymap.  GdkKeymap doesn't support
+ *  all our needs, therefore, we need to access lower level APIs.
+ *  But such code is usually complex and might be slow.  Against such issues,
+ *  we should cache some information.
+ *
+ *  This class provides only static methods.  The methods is using internal
+ *  singleton instance which is initialized by default GdkKeymap.  When the
+ *  GdkKeymap is destroyed, the singleton instance will be destroyed.
+ */
+
+class KeymapWrapper {
+ public:
+  /**
+   * Compute an our DOM keycode from a GDK keyval.
+   */
+  static uint32_t ComputeDOMKeyCode(const GdkEventKey* aGdkKeyEvent);
+
+  /**
+   * Compute a DOM key name index from aGdkKeyEvent.
+   */
+  static KeyNameIndex ComputeDOMKeyNameIndex(const GdkEventKey* aGdkKeyEvent);
+
+  /**
+   * Compute a DOM code name index from aGdkKeyEvent.
+   */
+  static CodeNameIndex ComputeDOMCodeNameIndex(const GdkEventKey* aGdkKeyEvent);
+
+  /**
+   * We need to translate modifiers masks from Gdk to Gecko.
+   * MappedModifier is a table of mapped modifiers, we ignore other
+   * Gdk ones.
+   */
+  enum MappedModifier {
+    NOT_MODIFIER = 0x0000,
+    CAPS_LOCK = 0x0001,
+    NUM_LOCK = 0x0002,
+    SCROLL_LOCK = 0x0004,
+    SHIFT = 0x0008,
+    CTRL = 0x0010,
+    ALT = 0x0020,
+    META = 0x0040,
+    SUPER = 0x0080,
+    HYPER = 0x0100,
+    LEVEL3 = 0x0200,
+    LEVEL5 = 0x0400
+  };
+
+  /**
+   * MappedModifiers is used for combination of MappedModifier.
+   * E.g., |MappedModifiers modifiers = (SHIFT | CTRL);| means Shift and Ctrl.
+   */
+  typedef uint32_t MappedModifiers;
+
+  /**
+   * GetCurrentModifierState() returns current modifier key state.
+   * The "current" means actual state of hardware keyboard when this is
+   * called.  I.e., if some key events are not still dispatched by GDK,
+   * the state may mismatch with GdkEventKey::state.
+   *
+   * @return                  Current modifier key state.
+   */
+  static guint GetCurrentModifierState();
+
+  /**
+   * Utility function to compute current keyboard modifiers for
+   * WidgetInputEvent
+   */
+  static uint32_t ComputeCurrentKeyModifiers();
+
+  /**
+   * Utility function to covert platform modifier state to keyboard modifiers
+   * of WidgetInputEvent
+   */
+  static uint32_t ComputeKeyModifiers(guint aGdkModifierState);
+
+  /**
+   * Convert native modifiers for `nsIWidget::SynthesizeNative*()` to
+   * GDK's state.
+   */
+  static guint ConvertWidgetModifierToGdkState(
+      nsIWidget::Modifiers aNativeModifiers);
+
+  /**
+   * InitInputEvent() initializes the aInputEvent with aModifierState.
+   */
+  static void InitInputEvent(WidgetInputEvent& aInputEvent,
+                             guint aGdkModifierState);
+
+  /**
+   * InitKeyEvent() intializes aKeyEvent's modifier key related members
+   * and keycode related values.
+   *
+   * @param aKeyEvent         It's an WidgetKeyboardEvent which needs to be
+   *                          initialized.
+   * @param aGdkKeyEvent      A native GDK key event.
+   * @param aIsProcessedByIME true if aGdkKeyEvent is handled by IME.
+   */
+  static void InitKeyEvent(WidgetKeyboardEvent& aKeyEvent,
+                           GdkEventKey* aGdkKeyEvent, bool aIsProcessedByIME);
+
+  /**
+   * DispatchKeyDownOrKeyUpEvent() dispatches eKeyDown or eKeyUp event.
+   *
+   * @param aWindow           The window to dispatch a keyboard event.
+   * @param aGdkKeyEvent      A native GDK_KEY_PRESS or GDK_KEY_RELEASE
+   *                          event.
+   * @param aIsProcessedByIME true if the event is handled by IME.
+   * @param aIsCancelled      [Out] true if the default is prevented.
+   * @return                  true if eKeyDown event is actually dispatched.
+   *                          Otherwise, false.
+   */
+  static bool DispatchKeyDownOrKeyUpEvent(nsWindow* aWindow,
+                                          GdkEventKey* aGdkKeyEvent,
+                                          bool aIsProcessedByIME,
+                                          bool* aIsCancelled);
+
+  /**
+   * DispatchKeyDownOrKeyUpEvent() dispatches eKeyDown or eKeyUp event.
+   *
+   * @param aWindow           The window to dispatch aKeyboardEvent.
+   * @param aKeyboardEvent    An eKeyDown or eKeyUp event.  This will be
+   *                          dispatched as is.
+   * @param aIsCancelled      [Out] true if the default is prevented.
+   * @return                  true if eKeyDown event is actually dispatched.
+   *                          Otherwise, false.
+   */
+  static bool DispatchKeyDownOrKeyUpEvent(nsWindow* aWindow,
+                                          WidgetKeyboardEvent& aKeyboardEvent,
+                                          bool* aIsCancelled);
+
+  /**
+   * GDK_KEY_PRESS event handler.
+   *
+   * @param aWindow           The window to dispatch eKeyDown event (and maybe
+   *                          eKeyPress events).
+   * @param aGdkKeyEvent      Receivied GDK_KEY_PRESS event.
+   */
+  static void HandleKeyPressEvent(nsWindow* aWindow, GdkEventKey* aGdkKeyEvent);
+
+  /**
+   * GDK_KEY_RELEASE event handler.
+   *
+   * @param aWindow           The window to dispatch eKeyUp event.
+   * @param aGdkKeyEvent      Receivied GDK_KEY_RELEASE event.
+   * @return                  true if an event is dispatched.  Otherwise, false.
+   */
+  static bool HandleKeyReleaseEvent(nsWindow* aWindow,
+                                    GdkEventKey* aGdkKeyEvent);
+
+  /**
+   * WillDispatchKeyboardEvent() is called via
+   * TextEventDispatcherListener::WillDispatchKeyboardEvent().
+   *
+   * @param aKeyEvent         An instance of KeyboardEvent which will be
+   *                          dispatched.  This method should set charCode
+   *                          and alternative char codes if it's necessary.
+   * @param aGdkKeyEvent      A GdkEventKey instance which caused the
+   *                          aKeyEvent.
+   */
+  static void WillDispatchKeyboardEvent(WidgetKeyboardEvent& aKeyEvent,
+                                        GdkEventKey* aGdkKeyEvent);
+
+#ifdef MOZ_WAYLAND
+  /**
+   * Utility function to set all supported modifier masks
+   * from xkb_keymap. We call that from Wayland backend routines.
+   */
+  static void SetModifierMasks(xkb_keymap* aKeymap);
+
+  /**
+   * Wayland global focus handlers
+   */
+  static void SetFocusIn(wl_surface* aFocusSurface, uint32_t aFocusSerial);
+  static void SetFocusOut(wl_surface* aFocusSurface);
+  static void GetFocusInfo(wl_surface** aFocusSurface, uint32_t* aFocusSerial);
+
+  static void SetSeat(wl_seat* aSeat, int aId);
+  static void ClearSeat(int aId);
+  static wl_seat* GetSeat();
+
+  static void SetKeyboard(wl_keyboard* aKeyboard);
+  static wl_keyboard* GetKeyboard();
+  static void ClearKeyboard();
+
+  /**
+   * EnsureInstance() is provided on Wayland to register Wayland callbacks
+   * early.
+   */
+  static void EnsureInstance();
+#endif
+
+  /**
+   * ResetKeyboard is called on keymap changes from OnKeysChanged and
+   * keyboard_handle_keymap to prepare for keymap changes.
+   */
+  static void ResetKeyboard();
+
+  /**
+   * Destroys the singleton KeymapWrapper instance, if it exists.
+   */
+  static void Shutdown();
+
+ private:
+  /**
+   * GetInstance() returns a KeymapWrapper instance.
+   *
+   * @return                  A singleton instance of KeymapWrapper.
+   */
+  static KeymapWrapper* GetInstance();
+
+  KeymapWrapper();
+  ~KeymapWrapper();
+
+  bool mInitialized;
+
+  /**
+   * Initializing methods.
+   */
+  void Init();
+#ifdef MOZ_X11
+  void InitXKBExtension();
+  void InitBySystemSettingsX11();
+#endif
+#ifdef MOZ_WAYLAND
+  void InitBySystemSettingsWayland();
+#endif
+
+  /**
+   * mModifierKeys stores each hardware key information.
+   */
+  struct ModifierKey {
+    guint mHardwareKeycode;
+    guint mMask;
+
+    explicit ModifierKey(guint aHardwareKeycode)
+        : mHardwareKeycode(aHardwareKeycode), mMask(0) {}
+  };
+  nsTArray<ModifierKey> mModifierKeys;
+
+  /**
+   * GetModifierKey() returns modifier key information of the hardware
+   * keycode.  If the key isn't a modifier key, returns nullptr.
+   */
+  ModifierKey* GetModifierKey(guint aHardwareKeycode);
+
+  /**
+   * mModifierMasks is bit masks for each modifier.  The index should be one
+   * of ModifierIndex values.
+   */
+  enum ModifierIndex {
+    INDEX_NUM_LOCK,
+    INDEX_SCROLL_LOCK,
+    INDEX_ALT,
+    INDEX_META,
+    INDEX_HYPER,
+    INDEX_LEVEL3,
+    INDEX_LEVEL5,
+    COUNT_OF_MODIFIER_INDEX
+  };
+  guint mModifierMasks[COUNT_OF_MODIFIER_INDEX];
+
+  guint GetGdkModifierMask(MappedModifier aModifier) const;
+
+  /**
+   * @param aGdkKeyval        A GDK defined modifier key value such as
+   *                          GDK_Shift_L.
+   * @return                  Returns MappedModifier values for aGdkKeyval.
+   *                          If the given key code isn't a modifier key,
+   *                          returns NOT_MODIFIER.
+   */
+  static MappedModifier GetModifierForGDKKeyval(guint aGdkKeyval);
+
+  static const char* GetModifierName(MappedModifier aModifier);
+
+  /**
+   * AreModifiersActive() just checks whether aGdkModifierState indicates
+   * all modifiers in aModifiers are active or not.
+   *
+   * @param aModifiers        One or more of MappedModifier values except
+   *                          NOT_MODIFIER.
+   * @param aGdkModifierState GDK's modifier states.
+   * @return                  TRUE if aGdkModifierType indicates all of
+   *                          modifiers in aModifier are active.
+   *                          Otherwise, FALSE.
+   */
+  static bool AreModifiersActive(MappedModifiers aModifiers,
+                                 guint aGdkModifierState);
+
+  /**
+   * mGdkKeymap is a wrapped instance by this class.
+   */
+  GdkKeymap* mGdkKeymap;
+
+  /**
+   * The base event code of XKB extension.
+   */
+  int mXKBBaseEventCode;
+
+#ifdef MOZ_X11
+  /**
+   * Only auto_repeats[] stores valid value.  If you need to use other
+   * members, you need to listen notification events for them.
+   * See a call of XkbSelectEventDetails() with XkbControlsNotify in
+   * InitXKBExtension().
+   */
+  XKeyboardState mKeyboardState;
+#endif
+
+  /**
+   * Pointer of the singleton instance.
+   */
+  static KeymapWrapper* sInstance;
+
+  /**
+   * Auto key repeat management.
+   */
+  static guint sLastRepeatableHardwareKeyCode;
+#ifdef MOZ_X11
+  static Time sLastRepeatableKeyTime;
+#endif
+  enum RepeatState { NOT_PRESSED, FIRST_PRESS, REPEATING };
+  static RepeatState sRepeatState;
+
+  /**
+   * IsAutoRepeatableKey() returns true if the key supports auto repeat.
+   * Otherwise, false.
+   */
+  bool IsAutoRepeatableKey(guint aHardwareKeyCode);
+
+  /**
+   * Signal handlers.
+   */
+  static void OnKeysChanged(GdkKeymap* aKeymap, KeymapWrapper* aKeymapWrapper);
+  static void OnDirectionChanged(GdkKeymap* aGdkKeymap,
+                                 KeymapWrapper* aKeymapWrapper);
+
+  gulong mOnKeysChangedSignalHandle;
+  gulong mOnDirectionChangedSignalHandle;
+
+  /**
+   * GetCharCodeFor() Computes what character is inputted by the key event
+   * with aModifierState and aGroup.
+   *
+   * @param aGdkKeyEvent      Native key event, must not be nullptr.
+   * @param aModifierState    Combination of GdkModifierType which you
+   *                          want to test with aGdkKeyEvent.
+   * @param aGroup            Set group in the mGdkKeymap.
+   * @return                  charCode which is inputted by aGdkKeyEvent.
+   *                          If failed, this returns 0.
+   */
+  static uint32_t GetCharCodeFor(const GdkEventKey* aGdkKeyEvent);
+  uint32_t GetCharCodeFor(const GdkEventKey* aGdkKeyEvent,
+                          guint aGdkModifierState, gint aGroup);
+
+  /**
+   * GetUnmodifiedCharCodeFor() computes what character is inputted by the
+   * key event without Ctrl/Alt/Meta/Super/Hyper modifiers.
+   * If Level3 or Level5 Shift causes no character input, this also ignores
+   * them.
+   *
+   * @param aGdkKeyEvent      Native key event, must not be nullptr.
+   * @return                  charCode which is computed without modifiers
+   *                          which prevent text input.
+   */
+  uint32_t GetUnmodifiedCharCodeFor(const GdkEventKey* aGdkKeyEvent);
+
+  /**
+   * GetKeyLevel() returns level of the aGdkKeyEvent in mGdkKeymap.
+   *
+   * @param aGdkKeyEvent      Native key event, must not be nullptr.
+   * @return                  Using level.  Typically, this is 0 or 1.
+   *                          If failed, this returns -1.
+   */
+  gint GetKeyLevel(GdkEventKey* aGdkKeyEvent);
+
+  /**
+   * GetFirstLatinGroup() returns group of mGdkKeymap which can input an
+   * ASCII character by GDK_A.
+   *
+   * @return                  group value of GdkEventKey.
+   */
+  gint GetFirstLatinGroup();
+
+  /**
+   * IsLatinGroup() checkes whether the keyboard layout of aGroup is
+   * ASCII alphabet inputtable or not.
+   *
+   * @param aGroup            The group value of GdkEventKey.
+   * @return                  TRUE if the keyboard layout can input
+   *                          ASCII alphabet.  Otherwise, FALSE.
+   */
+  bool IsLatinGroup(guint8 aGroup);
+
+  /**
+   * IsBasicLatinLetterOrNumeral() Checks whether the aCharCode is an
+   * alphabet or a numeric character in ASCII.
+   *
+   * @param aCharCode         Charcode which you want to test.
+   * @return                  TRUE if aCharCode is an alphabet or a numeric
+   *                          in ASCII range.  Otherwise, FALSE.
+   */
+  static bool IsBasicLatinLetterOrNumeral(uint32_t aCharCode);
+
+  /**
+   * IsPrintableASCIICharacter() checks whether the aCharCode is a printable
+   * ASCII character.  I.e., returns false if aCharCode is a control
+   * character even in an ASCII character.
+   */
+  static bool IsPrintableASCIICharacter(uint32_t aCharCode) {
+    return aCharCode >= 0x20 && aCharCode <= 0x7E;
+  }
+
+  /**
+   * GetGDKKeyvalWithoutModifier() returns the keyval for aGdkKeyEvent when
+   * ignoring the modifier state except NumLock. (NumLock is a key to change
+   * some key's meaning.)
+   */
+  static guint GetGDKKeyvalWithoutModifier(const GdkEventKey* aGdkKeyEvent);
+
+  /**
+   * GetDOMKeyCodeFromKeyPairs() returns DOM keycode for aGdkKeyval if
+   * it's in KeyPair table.
+   */
+  static uint32_t GetDOMKeyCodeFromKeyPairs(guint aGdkKeyval);
+
+#ifdef MOZ_X11
+  /**
+   * FilterEvents() listens all events on all our windows.
+   * Be careful, this may make damage to performance if you add expensive
+   * code in this method.
+   */
+  static GdkFilterReturn FilterEvents(GdkXEvent* aXEvent, GdkEvent* aGdkEvent,
+                                      gpointer aData);
+#endif
+
+  /**
+   * MaybeDispatchContextMenuEvent() may dispatch eContextMenu event if
+   * the given key combination should cause opening context menu.
+   *
+   * @param aWindow           The window to dispatch a contextmenu event.
+   * @param aEvent            The native key event.
+   * @return                  true if this method dispatched eContextMenu
+   *                          event.  Otherwise, false.
+   *                          Be aware, when this returns true, the
+   *                          widget may have been destroyed.
+   */
+  static bool MaybeDispatchContextMenuEvent(nsWindow* aWindow,
+                                            const GdkEventKey* aEvent);
+
+  /**
+   * See the document of WillDispatchKeyboardEvent().
+   */
+  void WillDispatchKeyboardEventInternal(WidgetKeyboardEvent& aKeyEvent,
+                                         GdkEventKey* aGdkKeyEvent);
+
+  static guint GetModifierState(GdkEventKey* aGdkKeyEvent,
+                                KeymapWrapper* aWrapper);
+
+#ifdef MOZ_WAYLAND
+  /**
+   * Utility function to set Xkb modifier key mask.
+   */
+  void SetModifierMask(xkb_keymap* aKeymap, ModifierIndex aModifierIndex,
+                       const char* aModifierName);
+#endif
+
+#ifdef MOZ_WAYLAND
+  static wl_seat* sSeat;
+  static int sSeatID;
+  static wl_keyboard* sKeyboard;
+  wl_surface* mFocusSurface = nullptr;
+  uint32_t mFocusSerial = 0;
+#endif
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __nsGdkKeyUtils_h__ */
diff --git a/widget/gtk/nsGtkUtils.h b/widget/gtk/nsGtkUtils.h
new file mode 100644
index 0000000000..ae26049e7f
--- /dev/null
+++ b/widget/gtk/nsGtkUtils.h
@@ -0,0 +1,59 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsGtkUtils_h__
+#define nsGtkUtils_h__
+
+#include <glib.h>
+
+// Some gobject functions expect functions for gpointer arguments.
+// gpointer is void* but C++ doesn't like casting functions to void*.
+template <class T>
+static inline gpointer FuncToGpointer(T aFunction) {
+  return reinterpret_cast<gpointer>(
+      reinterpret_cast<uintptr_t>
+      // This cast just provides a warning if T is not a function.
+      (reinterpret_cast<void (*)()>(aFunction)));
+}
+
+// Type-safe alternative to glib's g_clear_pointer.
+//
+// Using `g_clear_pointer` itself causes UBSan to report undefined
+// behavior. The function-based definition of `g_clear_pointer` (as
+// opposed to the older preprocessor macro) treats the `destroy`
+// function as a `void (*)(void *)`, but the actual destroy functions
+// that are used (say `wl_buffer_destroy`) usually have more specific
+// pointer types.
+//
+// C++ draft n4901 [expr.call] para 6:
+//
+//     Calling a function through an expression whose function type E
+//     is different from the function type F of the called function’s
+//     definition results in undefined behavior unless the type
+//     “pointer to F” can be converted to the type “pointer to E” via
+//     a function pointer conversion (7.3.14).
+//
+// §7.3.14 only talks about converting between noexcept and ordinary
+// function pointers.
+template <class T>
+static inline void MozClearPointer(T*& pointer, void (*destroy)(T*)) {
+  T* hold = pointer;
+  pointer = nullptr;
+  if (hold) {
+    destroy(hold);
+  }
+}
+
+template <class T>
+static inline void MozClearHandleID(T& handle, gboolean (*destroy)(T)) {
+  if (handle) {
+    destroy(handle);
+    handle = 0;
+  }
+}
+
+#endif  // nsGtkUtils_h__
diff --git a/widget/gtk/nsImageToPixbuf.cpp b/widget/gtk/nsImageToPixbuf.cpp
new file mode 100644
index 0000000000..73094b74ef
--- /dev/null
+++ b/widget/gtk/nsImageToPixbuf.cpp
@@ -0,0 +1,121 @@
+/* vim:set sw=2 sts=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <gdk-pixbuf/gdk-pixbuf.h>
+
+#include "nsImageToPixbuf.h"
+
+#include "imgIContainer.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/RefPtr.h"
+#include "GRefPtr.h"
+#include "nsCOMPtr.h"
+
+using mozilla::gfx::DataSourceSurface;
+using mozilla::gfx::SurfaceFormat;
+
+inline unsigned char unpremultiply(unsigned char color, unsigned char alpha) {
+  if (alpha == 0) return 0;
+  // plus alpha/2 to round instead of truncate
+  return (color * 255 + alpha / 2) / alpha;
+}
+
+already_AddRefed<GdkPixbuf> nsImageToPixbuf::ImageToPixbuf(
+    imgIContainer* aImage, const mozilla::Maybe<nsIntSize>& aOverrideSize) {
+  RefPtr<SourceSurface> surface;
+
+  const uint32_t flags =
+      imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY;
+  if (aOverrideSize) {
+    surface = aImage->GetFrameAtSize(*aOverrideSize,
+                                     imgIContainer::FRAME_CURRENT, flags);
+  } else {
+    surface = aImage->GetFrame(imgIContainer::FRAME_CURRENT, flags);
+  }
+
+  // If the last call failed, it was probably because our call stack originates
+  // in an imgINotificationObserver event, meaning that we're not allowed
+  // request a sync decode. Presumably the originating event is something
+  // sensible like OnStopFrame(), so we can just retry the call without a sync
+  // decode.
+  if (!surface) {
+    if (aOverrideSize) {
+      surface =
+          aImage->GetFrameAtSize(*aOverrideSize, imgIContainer::FRAME_CURRENT,
+                                 imgIContainer::FLAG_NONE);
+    } else {
+      surface = aImage->GetFrame(imgIContainer::FRAME_CURRENT,
+                                 imgIContainer::FLAG_NONE);
+    }
+  }
+
+  NS_ENSURE_TRUE(surface, nullptr);
+
+  return SourceSurfaceToPixbuf(surface, surface->GetSize().width,
+                               surface->GetSize().height);
+}
+
+already_AddRefed<GdkPixbuf> nsImageToPixbuf::SourceSurfaceToPixbuf(
+    SourceSurface* aSurface, int32_t aWidth, int32_t aHeight) {
+  MOZ_ASSERT(aWidth <= aSurface->GetSize().width &&
+                 aHeight <= aSurface->GetSize().height,
+             "Requested rect is bigger than the supplied surface");
+
+  RefPtr<GdkPixbuf> pixbuf =
+      dont_AddRef(gdk_pixbuf_new(GDK_COLORSPACE_RGB, TRUE, 8, aWidth, aHeight));
+  if (!pixbuf) {
+    return nullptr;
+  }
+
+  uint32_t destStride = gdk_pixbuf_get_rowstride(pixbuf);
+  guchar* destPixels = gdk_pixbuf_get_pixels(pixbuf);
+
+  RefPtr<DataSourceSurface> dataSurface = aSurface->GetDataSurface();
+  DataSourceSurface::MappedSurface map;
+  if (!dataSurface->Map(DataSourceSurface::MapType::READ, &map)) {
+    return nullptr;
+  }
+
+  uint8_t* srcData = map.mData;
+  int32_t srcStride = map.mStride;
+
+  SurfaceFormat format = dataSurface->GetFormat();
+
+  for (int32_t row = 0; row < aHeight; ++row) {
+    for (int32_t col = 0; col < aWidth; ++col) {
+      guchar* destPixel = destPixels + row * destStride + 4 * col;
+
+      uint32_t* srcPixel =
+          reinterpret_cast<uint32_t*>((srcData + row * srcStride + 4 * col));
+
+      if (format == SurfaceFormat::B8G8R8A8) {
+        const uint8_t a = (*srcPixel >> 24) & 0xFF;
+        const uint8_t r = unpremultiply((*srcPixel >> 16) & 0xFF, a);
+        const uint8_t g = unpremultiply((*srcPixel >> 8) & 0xFF, a);
+        const uint8_t b = unpremultiply((*srcPixel >> 0) & 0xFF, a);
+
+        *destPixel++ = r;
+        *destPixel++ = g;
+        *destPixel++ = b;
+        *destPixel++ = a;
+      } else {
+        MOZ_ASSERT(format == SurfaceFormat::B8G8R8X8);
+
+        const uint8_t r = (*srcPixel >> 16) & 0xFF;
+        const uint8_t g = (*srcPixel >> 8) & 0xFF;
+        const uint8_t b = (*srcPixel >> 0) & 0xFF;
+
+        *destPixel++ = r;
+        *destPixel++ = g;
+        *destPixel++ = b;
+        *destPixel++ = 0xFF;  // A
+      }
+    }
+  }
+
+  dataSurface->Unmap();
+
+  return pixbuf.forget();
+}
diff --git a/widget/gtk/nsImageToPixbuf.h b/widget/gtk/nsImageToPixbuf.h
new file mode 100644
index 0000000000..500489d7eb
--- /dev/null
+++ b/widget/gtk/nsImageToPixbuf.h
@@ -0,0 +1,37 @@
+/* vim:set sw=2 sts=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NSIMAGETOPIXBUF_H_
+#define NSIMAGETOPIXBUF_H_
+
+#include "mozilla/Attributes.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/RefPtr.h"
+#include "nsSize.h"
+
+class imgIContainer;
+typedef struct _GdkPixbuf GdkPixbuf;
+
+namespace mozilla::gfx {
+class SourceSurface;
+}  // namespace mozilla::gfx
+
+class nsImageToPixbuf final {
+  using SourceSurface = mozilla::gfx::SourceSurface;
+
+ public:
+  // Friendlier version of ConvertImageToPixbuf for callers inside of
+  // widget
+  static already_AddRefed<GdkPixbuf> ImageToPixbuf(
+      imgIContainer* aImage,
+      const mozilla::Maybe<nsIntSize>& aOverrideSize = mozilla::Nothing());
+  static already_AddRefed<GdkPixbuf> SourceSurfaceToPixbuf(
+      SourceSurface* aSurface, int32_t aWidth, int32_t aHeight);
+
+ private:
+  ~nsImageToPixbuf() = default;
+};
+
+#endif
diff --git a/widget/gtk/nsLookAndFeel.cpp b/widget/gtk/nsLookAndFeel.cpp
new file mode 100644
index 0000000000..c4b430d2eb
--- /dev/null
+++ b/widget/gtk/nsLookAndFeel.cpp
@@ -0,0 +1,2329 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// for strtod()
+#include <stdlib.h>
+#include <dlfcn.h>
+
+#include "nsLookAndFeel.h"
+
+#include <gtk/gtk.h>
+#include <gdk/gdk.h>
+
+#include <pango/pango.h>
+#include <pango/pango-fontmap.h>
+#include <fontconfig/fontconfig.h>
+
+#include "GRefPtr.h"
+#include "GUniquePtr.h"
+#include "nsGtkUtils.h"
+#include "gfxPlatformGtk.h"
+#include "mozilla/FontPropertyTypes.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/RelativeLuminanceUtils.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/WidgetUtilsGtk.h"
+#include "ScreenHelperGTK.h"
+#include "ScrollbarDrawing.h"
+
+#include "gtkdrawing.h"
+#include "nsString.h"
+#include "nsStyleConsts.h"
+#include "gfxFontConstants.h"
+#include "WidgetUtils.h"
+#include "nsWindow.h"
+
+#include "mozilla/gfx/2D.h"
+
+#include <cairo-gobject.h>
+#include <dlfcn.h>
+#include "WidgetStyleCache.h"
+#include "prenv.h"
+#include "nsCSSColorUtils.h"
+#include "mozilla/Preferences.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+#ifdef MOZ_LOGGING
+#  include "mozilla/Logging.h"
+#  include "nsTArray.h"
+#  include "Units.h"
+static LazyLogModule gLnfLog("LookAndFeel");
+#  define LOGLNF(...) MOZ_LOG(gLnfLog, LogLevel::Debug, (__VA_ARGS__))
+#  define LOGLNF_ENABLED() MOZ_LOG_TEST(gLnfLog, LogLevel::Debug)
+#else
+#  define LOGLNF(args)
+#  define LOGLNF_ENABLED() false
+#endif /* MOZ_LOGGING */
+
+#define GDK_COLOR_TO_NS_RGB(c) \
+  ((nscolor)NS_RGB(c.red >> 8, c.green >> 8, c.blue >> 8))
+#define GDK_RGBA_TO_NS_RGBA(c)                                    \
+  ((nscolor)NS_RGBA((int)((c).red * 255), (int)((c).green * 255), \
+                    (int)((c).blue * 255), (int)((c).alpha * 255)))
+
+static bool sIgnoreChangedSettings = false;
+
+static void OnSettingsChange() {
+  if (sIgnoreChangedSettings) {
+    return;
+  }
+  // TODO: We could be more granular here, but for now assume everything
+  // changed.
+  LookAndFeel::NotifyChangedAllWindows(widget::ThemeChangeKind::StyleAndLayout);
+  widget::IMContextWrapper::OnThemeChanged();
+}
+
+static void settings_changed_cb(GtkSettings*, GParamSpec*, void*) {
+  OnSettingsChange();
+}
+
+static bool sCSDAvailable;
+
+static nsCString GVariantToString(GVariant* aVariant) {
+  nsCString ret;
+  gchar* s = g_variant_print(aVariant, TRUE);
+  if (s) {
+    ret.Assign(s);
+    g_free(s);
+  }
+  return ret;
+}
+
+static nsDependentCString GVariantGetString(GVariant* aVariant) {
+  gsize len = 0;
+  const gchar* v = g_variant_get_string(aVariant, &len);
+  return nsDependentCString(v, len);
+}
+
+static void settings_changed_signal_cb(GDBusProxy* proxy, gchar* sender_name,
+                                       gchar* signal_name, GVariant* parameters,
+                                       gpointer user_data) {
+  LOGLNF("Settings Change sender=%s signal=%s params=%s\n", sender_name,
+         signal_name, GVariantToString(parameters).get());
+  if (strcmp(signal_name, "SettingChanged")) {
+    NS_WARNING("Unknown change signal for settings");
+    return;
+  }
+  RefPtr<GVariant> ns = dont_AddRef(g_variant_get_child_value(parameters, 0));
+  RefPtr<GVariant> key = dont_AddRef(g_variant_get_child_value(parameters, 1));
+  // Third parameter is the value, but we don't care about it.
+  if (!ns || !key || !g_variant_is_of_type(ns, G_VARIANT_TYPE_STRING) ||
+      !g_variant_is_of_type(key, G_VARIANT_TYPE_STRING)) {
+    MOZ_ASSERT(false, "Unexpected setting change signal parameters");
+    return;
+  }
+
+  auto* lnf = static_cast<nsLookAndFeel*>(user_data);
+
+  auto nsStr = GVariantGetString(ns);
+  auto keyStr = GVariantGetString(key);
+  if (nsStr.Equals("org.freedesktop.appearance"_ns) &&
+      keyStr.Equals("color-scheme"_ns)) {
+    lnf->OnColorSchemeSettingChanged();
+  }
+}
+
+void nsLookAndFeel::WatchDBus() {
+  GUniquePtr<GError> error;
+  mDBusSettingsProxy = dont_AddRef(g_dbus_proxy_new_for_bus_sync(
+      G_BUS_TYPE_SESSION, G_DBUS_PROXY_FLAGS_NONE, nullptr,
+      "org.freedesktop.portal.Desktop", "/org/freedesktop/portal/desktop",
+      "org.freedesktop.portal.Settings", nullptr, getter_Transfers(error)));
+  if (mDBusSettingsProxy) {
+    g_signal_connect(mDBusSettingsProxy, "g-signal",
+                     G_CALLBACK(settings_changed_signal_cb), this);
+  } else {
+    LOGLNF("Can't create DBus proxy for settings: %s\n", error->message);
+    return;
+  }
+
+  // DBus interface was started after L&F init so we need to load
+  // our settings from DBus explicitly.
+  if (!sIgnoreChangedSettings) {
+    OnColorSchemeSettingChanged();
+  }
+}
+
+void nsLookAndFeel::UnwatchDBus() {
+  if (mDBusSettingsProxy) {
+    g_signal_handlers_disconnect_by_func(
+        mDBusSettingsProxy, FuncToGpointer(settings_changed_signal_cb), this);
+    mDBusSettingsProxy = nullptr;
+  }
+}
+
+nsLookAndFeel::nsLookAndFeel() {
+  static constexpr nsLiteralCString kObservedSettings[] = {
+      // Affects system font sizes.
+      "notify::gtk-xft-dpi"_ns,
+      // Affects mSystemTheme and mAltTheme as expected.
+      "notify::gtk-theme-name"_ns,
+      // System fonts?
+      "notify::gtk-font-name"_ns,
+      // prefers-reduced-motion
+      "notify::gtk-enable-animations"_ns,
+      // CSD media queries, etc.
+      "notify::gtk-decoration-layout"_ns,
+      // Text resolution affects system font and widget sizes.
+      "notify::resolution"_ns,
+      // These three Affect mCaretBlinkTime
+      "notify::gtk-cursor-blink"_ns,
+      "notify::gtk-cursor-blink-time"_ns,
+      "notify::gtk-cursor-blink-timeout"_ns,
+      // Affects SelectTextfieldsOnKeyFocus
+      "notify::gtk-entry-select-on-focus"_ns,
+      // Affects ScrollToClick
+      "notify::gtk-primary-button-warps-slider"_ns,
+      // Affects SubmenuDelay
+      "notify::gtk-menu-popup-delay"_ns,
+      // Affects DragThresholdX/Y
+      "notify::gtk-dnd-drag-threshold"_ns,
+      // Affects titlebar actions loaded at moz_gtk_refresh().
+      "notify::gtk-titlebar-double-click"_ns,
+      "notify::gtk-titlebar-middle-click"_ns,
+  };
+
+  GtkSettings* settings = gtk_settings_get_default();
+  for (const auto& setting : kObservedSettings) {
+    g_signal_connect_after(settings, setting.get(),
+                           G_CALLBACK(settings_changed_cb), nullptr);
+  }
+
+  sCSDAvailable =
+      nsWindow::GetSystemGtkWindowDecoration() != nsWindow::GTK_DECORATION_NONE;
+
+  if (ShouldUsePortal(PortalKind::Settings)) {
+    mDBusID = g_bus_watch_name(
+        G_BUS_TYPE_SESSION, "org.freedesktop.portal.Desktop",
+        G_BUS_NAME_WATCHER_FLAGS_AUTO_START,
+        [](GDBusConnection*, const gchar*, const gchar*,
+           gpointer data) -> void {
+          auto* lnf = static_cast<nsLookAndFeel*>(data);
+          lnf->WatchDBus();
+        },
+        [](GDBusConnection*, const gchar*, gpointer data) -> void {
+          auto* lnf = static_cast<nsLookAndFeel*>(data);
+          lnf->UnwatchDBus();
+        },
+        this, nullptr);
+  }
+  if (IsKdeDesktopEnvironment()) {
+    GUniquePtr<gchar> path(
+        g_strconcat(g_get_user_config_dir(), "/gtk-3.0/colors.css", NULL));
+    mKdeColors = dont_AddRef(g_file_new_for_path(path.get()));
+    mKdeColorsMonitor = dont_AddRef(
+        g_file_monitor_file(mKdeColors.get(), G_FILE_MONITOR_NONE, NULL, NULL));
+    if (mKdeColorsMonitor) {
+      g_signal_connect(mKdeColorsMonitor.get(), "changed",
+                       G_CALLBACK(settings_changed_cb), NULL);
+    }
+  }
+}
+
+nsLookAndFeel::~nsLookAndFeel() {
+  ClearRoundedCornerProvider();
+  if (mDBusID) {
+    g_bus_unwatch_name(mDBusID);
+    mDBusID = 0;
+  }
+  UnwatchDBus();
+  g_signal_handlers_disconnect_by_func(
+      gtk_settings_get_default(), FuncToGpointer(settings_changed_cb), nullptr);
+}
+
+#if 0
+static void DumpStyleContext(GtkStyleContext* aStyle) {
+  static auto sGtkStyleContextToString =
+      reinterpret_cast<char* (*)(GtkStyleContext*, gint)>(
+          dlsym(RTLD_DEFAULT, "gtk_style_context_to_string"));
+  char* str = sGtkStyleContextToString(aStyle, ~0);
+  printf("%s\n", str);
+  g_free(str);
+  str = gtk_widget_path_to_string(gtk_style_context_get_path(aStyle));
+  printf("%s\n", str);
+  g_free(str);
+}
+#endif
+
+// Modifies color |*aDest| as if a pattern of color |aSource| was painted with
+// CAIRO_OPERATOR_OVER to a surface with color |*aDest|.
+static void ApplyColorOver(const GdkRGBA& aSource, GdkRGBA* aDest) {
+  gdouble sourceCoef = aSource.alpha;
+  gdouble destCoef = aDest->alpha * (1.0 - sourceCoef);
+  gdouble resultAlpha = sourceCoef + destCoef;
+  if (resultAlpha != 0.0) {  // don't divide by zero
+    destCoef /= resultAlpha;
+    sourceCoef /= resultAlpha;
+    aDest->red = sourceCoef * aSource.red + destCoef * aDest->red;
+    aDest->green = sourceCoef * aSource.green + destCoef * aDest->green;
+    aDest->blue = sourceCoef * aSource.blue + destCoef * aDest->blue;
+    aDest->alpha = resultAlpha;
+  }
+}
+
+static void GetLightAndDarkness(const GdkRGBA& aColor, double* aLightness,
+                                double* aDarkness) {
+  double sum = aColor.red + aColor.green + aColor.blue;
+  *aLightness = sum * aColor.alpha;
+  *aDarkness = (3.0 - sum) * aColor.alpha;
+}
+
+static bool GetGradientColors(const GValue* aValue, GdkRGBA* aLightColor,
+                              GdkRGBA* aDarkColor) {
+  if (!G_TYPE_CHECK_VALUE_TYPE(aValue, CAIRO_GOBJECT_TYPE_PATTERN)) {
+    return false;
+  }
+
+  auto pattern = static_cast<cairo_pattern_t*>(g_value_get_boxed(aValue));
+  if (!pattern) {
+    return false;
+  }
+
+  // Just picking the lightest and darkest colors as simple samples rather
+  // than trying to blend, which could get messy if there are many stops.
+  if (CAIRO_STATUS_SUCCESS !=
+      cairo_pattern_get_color_stop_rgba(pattern, 0, nullptr, &aDarkColor->red,
+                                        &aDarkColor->green, &aDarkColor->blue,
+                                        &aDarkColor->alpha)) {
+    return false;
+  }
+
+  double maxLightness, maxDarkness;
+  GetLightAndDarkness(*aDarkColor, &maxLightness, &maxDarkness);
+  *aLightColor = *aDarkColor;
+
+  GdkRGBA stop;
+  for (int index = 1;
+       CAIRO_STATUS_SUCCESS ==
+       cairo_pattern_get_color_stop_rgba(pattern, index, nullptr, &stop.red,
+                                         &stop.green, &stop.blue, &stop.alpha);
+       ++index) {
+    double lightness, darkness;
+    GetLightAndDarkness(stop, &lightness, &darkness);
+    if (lightness > maxLightness) {
+      maxLightness = lightness;
+      *aLightColor = stop;
+    }
+    if (darkness > maxDarkness) {
+      maxDarkness = darkness;
+      *aDarkColor = stop;
+    }
+  }
+
+  return true;
+}
+
+static bool GetColorFromImagePattern(const GValue* aValue, nscolor* aColor) {
+  if (!G_TYPE_CHECK_VALUE_TYPE(aValue, CAIRO_GOBJECT_TYPE_PATTERN)) {
+    return false;
+  }
+
+  auto* pattern = static_cast<cairo_pattern_t*>(g_value_get_boxed(aValue));
+  if (!pattern) {
+    return false;
+  }
+
+  cairo_surface_t* surface;
+  if (cairo_pattern_get_surface(pattern, &surface) != CAIRO_STATUS_SUCCESS) {
+    return false;
+  }
+
+  cairo_format_t format = cairo_image_surface_get_format(surface);
+  if (format == CAIRO_FORMAT_INVALID) {
+    return false;
+  }
+  int width = cairo_image_surface_get_width(surface);
+  int height = cairo_image_surface_get_height(surface);
+  int stride = cairo_image_surface_get_stride(surface);
+  if (!width || !height) {
+    return false;
+  }
+
+  // Guesstimate the central pixel would have a sensible color.
+  int x = width / 2;
+  int y = height / 2;
+
+  unsigned char* data = cairo_image_surface_get_data(surface);
+  switch (format) {
+    // Most (all?) GTK images / patterns / etc use ARGB32.
+    case CAIRO_FORMAT_ARGB32: {
+      size_t offset = x * 4 + y * stride;
+      uint32_t* pixel = reinterpret_cast<uint32_t*>(data + offset);
+      *aColor = gfx::sRGBColor::UnusualFromARGB(*pixel).ToABGR();
+      return true;
+    }
+    default:
+      break;
+  }
+
+  return false;
+}
+
+static bool GetUnicoBorderGradientColors(GtkStyleContext* aContext,
+                                         GdkRGBA* aLightColor,
+                                         GdkRGBA* aDarkColor) {
+  // Ubuntu 12.04 has GTK engine Unico-1.0.2, which overrides render_frame,
+  // providing its own border code.  Ubuntu 14.04 has
+  // Unico-1.0.3+14.04.20140109, which does not override render_frame, and
+  // so does not need special attention.  The earlier Unico can be detected
+  // by the -unico-border-gradient style property it registers.
+  // gtk_style_properties_lookup_property() is checked first to avoid the
+  // warning from gtk_style_context_get_property() when the property does
+  // not exist.  (gtk_render_frame() of GTK+ 3.16 no longer uses the
+  // engine.)
+  const char* propertyName = "-unico-border-gradient";
+  if (!gtk_style_properties_lookup_property(propertyName, nullptr, nullptr))
+    return false;
+
+  // -unico-border-gradient is used only when the CSS node's engine is Unico.
+  GtkThemingEngine* engine;
+  GtkStateFlags state = gtk_style_context_get_state(aContext);
+  gtk_style_context_get(aContext, state, "engine", &engine, nullptr);
+  if (strcmp(g_type_name(G_TYPE_FROM_INSTANCE(engine)), "UnicoEngine") != 0)
+    return false;
+
+  // draw_border() of Unico engine uses -unico-border-gradient
+  // in preference to border-color.
+  GValue value = G_VALUE_INIT;
+  gtk_style_context_get_property(aContext, propertyName, state, &value);
+
+  bool result = GetGradientColors(&value, aLightColor, aDarkColor);
+
+  g_value_unset(&value);
+  return result;
+}
+
+// Sets |aLightColor| and |aDarkColor| to colors from |aContext|.  Returns
+// true if |aContext| uses these colors to render a visible border.
+// If returning false, then the colors returned are a fallback from the
+// border-color value even though |aContext| does not use these colors to
+// render a border.
+static bool GetBorderColors(GtkStyleContext* aContext, GdkRGBA* aLightColor,
+                            GdkRGBA* aDarkColor) {
+  // Determine whether the border on this style context is visible.
+  GtkStateFlags state = gtk_style_context_get_state(aContext);
+  GtkBorderStyle borderStyle;
+  gtk_style_context_get(aContext, state, GTK_STYLE_PROPERTY_BORDER_STYLE,
+                        &borderStyle, nullptr);
+  bool visible = borderStyle != GTK_BORDER_STYLE_NONE &&
+                 borderStyle != GTK_BORDER_STYLE_HIDDEN;
+  if (visible) {
+    // GTK has an initial value of zero for border-widths, and so themes
+    // need to explicitly set border-widths to make borders visible.
+    GtkBorder border;
+    gtk_style_context_get_border(aContext, state, &border);
+    visible = border.top != 0 || border.right != 0 || border.bottom != 0 ||
+              border.left != 0;
+  }
+
+  if (visible &&
+      GetUnicoBorderGradientColors(aContext, aLightColor, aDarkColor))
+    return true;
+
+  // The initial value for the border-color is the foreground color, and so
+  // this will usually return a color distinct from the background even if
+  // there is no visible border detected.
+  gtk_style_context_get_border_color(aContext, state, aDarkColor);
+  // TODO GTK3 - update aLightColor
+  // for GTK_BORDER_STYLE_INSET/OUTSET/GROVE/RIDGE border styles.
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=978172#c25
+  *aLightColor = *aDarkColor;
+  return visible;
+}
+
+static bool GetBorderColors(GtkStyleContext* aContext, nscolor* aLightColor,
+                            nscolor* aDarkColor) {
+  GdkRGBA lightColor, darkColor;
+  bool ret = GetBorderColors(aContext, &lightColor, &darkColor);
+  *aLightColor = GDK_RGBA_TO_NS_RGBA(lightColor);
+  *aDarkColor = GDK_RGBA_TO_NS_RGBA(darkColor);
+  return ret;
+}
+
+// Finds ideal cell highlight colors used for unfocused+selected cells distinct
+// from both Highlight, used as focused+selected background, and the listbox
+// background which is assumed to be similar to -moz-field
+void nsLookAndFeel::PerThemeData::InitCellHighlightColors() {
+  int32_t minLuminosityDifference = NS_SUFFICIENT_LUMINOSITY_DIFFERENCE_BG;
+  int32_t backLuminosityDifference =
+      NS_LUMINOSITY_DIFFERENCE(mWindow.mBg, mField.mBg);
+  if (backLuminosityDifference >= minLuminosityDifference) {
+    mCellHighlight = mWindow;
+    return;
+  }
+
+  uint16_t hue, sat, luminance;
+  uint8_t alpha;
+  mCellHighlight = mField;
+
+  NS_RGB2HSV(mCellHighlight.mBg, hue, sat, luminance, alpha);
+
+  uint16_t step = 30;
+  // Lighten the color if the color is very dark
+  if (luminance <= step) {
+    luminance += step;
+  }
+  // Darken it if it is very light
+  else if (luminance >= 255 - step) {
+    luminance -= step;
+  }
+  // Otherwise, compute what works best depending on the text luminance.
+  else {
+    uint16_t textHue, textSat, textLuminance;
+    uint8_t textAlpha;
+    NS_RGB2HSV(mCellHighlight.mFg, textHue, textSat, textLuminance, textAlpha);
+    // Text is darker than background, use a lighter shade
+    if (textLuminance < luminance) {
+      luminance += step;
+    }
+    // Otherwise, use a darker shade
+    else {
+      luminance -= step;
+    }
+  }
+  NS_HSV2RGB(mCellHighlight.mBg, hue, sat, luminance, alpha);
+}
+
+void nsLookAndFeel::NativeInit() { EnsureInit(); }
+
+void nsLookAndFeel::RefreshImpl() {
+  mInitialized = false;
+  moz_gtk_refresh();
+
+  nsXPLookAndFeel::RefreshImpl();
+}
+
+nsresult nsLookAndFeel::NativeGetColor(ColorID aID, ColorScheme aScheme,
+                                       nscolor& aColor) {
+  EnsureInit();
+
+  const auto& theme =
+      aScheme == ColorScheme::Light ? LightTheme() : DarkTheme();
+  return theme.GetColor(aID, aColor);
+}
+
+static bool ShouldUseColorForActiveDarkScrollbarThumb(nscolor aColor) {
+  auto IsDifferentEnough = [](int32_t aChannel, int32_t aOtherChannel) {
+    return std::abs(aChannel - aOtherChannel) > 10;
+  };
+  return IsDifferentEnough(NS_GET_R(aColor), NS_GET_G(aColor)) ||
+         IsDifferentEnough(NS_GET_R(aColor), NS_GET_B(aColor));
+}
+
+static bool ShouldUseThemedScrollbarColor(StyleSystemColor aID, nscolor aColor,
+                                          bool aIsDark) {
+  if (!aIsDark) {
+    return true;
+  }
+  if (StaticPrefs::widget_non_native_theme_scrollbar_dark_themed()) {
+    return true;
+  }
+  return aID == StyleSystemColor::ThemedScrollbarThumbActive &&
+         StaticPrefs::widget_non_native_theme_scrollbar_active_always_themed();
+}
+
+nsresult nsLookAndFeel::PerThemeData::GetColor(ColorID aID,
+                                               nscolor& aColor) const {
+  nsresult res = NS_OK;
+
+  switch (aID) {
+      // These colors don't seem to be used for anything anymore in Mozilla
+      // The CSS2 colors below are used.
+    case ColorID::Appworkspace:  // MDI background color
+    case ColorID::Background:    // desktop background
+    case ColorID::Window:
+    case ColorID::Windowframe:
+    case ColorID::MozCombobox:
+      aColor = mWindow.mBg;
+      break;
+    case ColorID::Windowtext:
+      aColor = mWindow.mFg;
+      break;
+    case ColorID::MozDialog:
+      aColor = mDialog.mBg;
+      break;
+    case ColorID::MozDialogtext:
+      aColor = mDialog.mFg;
+      break;
+    case ColorID::IMESelectedRawTextBackground:
+    case ColorID::IMESelectedConvertedTextBackground:
+    case ColorID::Highlight:  // preference selected item,
+      aColor = mSelectedText.mBg;
+      break;
+    case ColorID::Highlighttext:
+      if (NS_GET_A(mSelectedText.mBg) < 155) {
+        aColor = NS_SAME_AS_FOREGROUND_COLOR;
+        break;
+      }
+      [[fallthrough]];
+    case ColorID::IMESelectedRawTextForeground:
+    case ColorID::IMESelectedConvertedTextForeground:
+      aColor = mSelectedText.mFg;
+      break;
+    case ColorID::Selecteditem:
+      aColor = mSelectedItem.mBg;
+      break;
+    case ColorID::Selecteditemtext:
+      aColor = mSelectedItem.mFg;
+      break;
+    case ColorID::Accentcolor:
+      aColor = mAccent.mBg;
+      break;
+    case ColorID::Accentcolortext:
+      aColor = mAccent.mFg;
+      break;
+    case ColorID::MozCellhighlight:
+      aColor = mCellHighlight.mBg;
+      break;
+    case ColorID::MozCellhighlighttext:
+      aColor = mCellHighlight.mFg;
+      break;
+    case ColorID::IMERawInputBackground:
+    case ColorID::IMEConvertedTextBackground:
+      aColor = NS_TRANSPARENT;
+      break;
+    case ColorID::IMERawInputForeground:
+    case ColorID::IMEConvertedTextForeground:
+      aColor = NS_SAME_AS_FOREGROUND_COLOR;
+      break;
+    case ColorID::IMERawInputUnderline:
+    case ColorID::IMEConvertedTextUnderline:
+      aColor = NS_SAME_AS_FOREGROUND_COLOR;
+      break;
+    case ColorID::IMESelectedRawTextUnderline:
+    case ColorID::IMESelectedConvertedTextUnderline:
+      aColor = NS_TRANSPARENT;
+      break;
+    case ColorID::Scrollbar:
+      aColor = mThemedScrollbar;
+      break;
+    case ColorID::ThemedScrollbar:
+      aColor = mThemedScrollbar;
+      if (!ShouldUseThemedScrollbarColor(aID, aColor, mIsDark)) {
+        return NS_ERROR_FAILURE;
+      }
+      break;
+    case ColorID::ThemedScrollbarInactive:
+      aColor = mThemedScrollbarInactive;
+      if (!ShouldUseThemedScrollbarColor(aID, aColor, mIsDark)) {
+        return NS_ERROR_FAILURE;
+      }
+      break;
+    case ColorID::ThemedScrollbarThumb:
+      aColor = mThemedScrollbarThumb;
+      if (!ShouldUseThemedScrollbarColor(aID, aColor, mIsDark)) {
+        return NS_ERROR_FAILURE;
+      }
+      break;
+    case ColorID::ThemedScrollbarThumbHover:
+      aColor = mThemedScrollbarThumbHover;
+      if (!ShouldUseThemedScrollbarColor(aID, aColor, mIsDark)) {
+        return NS_ERROR_FAILURE;
+      }
+      break;
+    case ColorID::ThemedScrollbarThumbActive:
+      aColor = mThemedScrollbarThumbActive;
+      if (!ShouldUseThemedScrollbarColor(aID, aColor, mIsDark)) {
+        return NS_ERROR_FAILURE;
+      }
+      break;
+    case ColorID::ThemedScrollbarThumbInactive:
+      aColor = mThemedScrollbarThumbInactive;
+      if (!ShouldUseThemedScrollbarColor(aID, aColor, mIsDark)) {
+        return NS_ERROR_FAILURE;
+      }
+      break;
+
+      // css2  http://www.w3.org/TR/REC-CSS2/ui.html#system-colors
+    case ColorID::Activeborder:
+      // active window border
+      aColor = mMozWindowActiveBorder;
+      break;
+    case ColorID::Inactiveborder:
+      // inactive window border
+      aColor = mMozWindowInactiveBorder;
+      break;
+    case ColorID::Graytext:  // disabled text in windows, menus, etc.
+      aColor = mGrayText;
+      break;
+    case ColorID::Activecaption:
+      aColor = mTitlebar.mBg;
+      break;
+    case ColorID::Captiontext:  // text in active window caption (titlebar)
+      aColor = mTitlebar.mFg;
+      break;
+    case ColorID::Inactivecaption:
+      // inactive window caption
+      aColor = mTitlebarInactive.mBg;
+      break;
+    case ColorID::Inactivecaptiontext:
+      aColor = mTitlebarInactive.mFg;
+      break;
+    case ColorID::Infobackground:
+      aColor = mInfo.mBg;
+      break;
+    case ColorID::Infotext:
+      aColor = mInfo.mFg;
+      break;
+    case ColorID::Menu:
+      aColor = mMenu.mBg;
+      break;
+    case ColorID::Menutext:
+      aColor = mMenu.mFg;
+      break;
+    case ColorID::MozHeaderbar:
+      aColor = mHeaderBar.mBg;
+      break;
+    case ColorID::MozHeaderbartext:
+      aColor = mHeaderBar.mFg;
+      break;
+    case ColorID::MozHeaderbarinactive:
+      aColor = mHeaderBarInactive.mBg;
+      break;
+    case ColorID::MozHeaderbarinactivetext:
+      aColor = mHeaderBarInactive.mFg;
+      break;
+    case ColorID::Threedface:
+    case ColorID::Buttonface:
+    case ColorID::MozButtondisabledface:
+      // 3-D face color
+      aColor = mWindow.mBg;
+      break;
+
+    case ColorID::Buttontext:
+      // text on push buttons
+      aColor = mButton.mFg;
+      break;
+
+    case ColorID::Buttonhighlight:
+      // 3-D highlighted edge color
+    case ColorID::Threedhighlight:
+      // 3-D highlighted outer edge color
+      aColor = mThreeDHighlight;
+      break;
+
+    case ColorID::Buttonshadow:
+      // 3-D shadow edge color
+    case ColorID::Threedshadow:
+      // 3-D shadow inner edge color
+      aColor = mThreeDShadow;
+      break;
+    case ColorID::Buttonborder:
+      aColor = mButtonBorder;
+      break;
+    case ColorID::Threedlightshadow:
+    case ColorID::MozDisabledfield:
+      aColor = mIsDark ? *GenericDarkColor(aID) : NS_RGB(0xE0, 0xE0, 0xE0);
+      break;
+    case ColorID::Threeddarkshadow:
+      aColor = mIsDark ? *GenericDarkColor(aID) : NS_RGB(0xDC, 0xDC, 0xDC);
+      break;
+
+    case ColorID::MozEventreerow:
+    case ColorID::Field:
+      aColor = mField.mBg;
+      break;
+    case ColorID::Fieldtext:
+      aColor = mField.mFg;
+      break;
+    case ColorID::MozSidebar:
+      aColor = mSidebar.mBg;
+      break;
+    case ColorID::MozSidebartext:
+      aColor = mSidebar.mFg;
+      break;
+    case ColorID::MozSidebarborder:
+      aColor = mSidebarBorder;
+      break;
+    case ColorID::MozButtonhoverface:
+      aColor = mButtonHover.mBg;
+      break;
+    case ColorID::MozButtonhovertext:
+      aColor = mButtonHover.mFg;
+      break;
+    case ColorID::MozButtonactiveface:
+      aColor = mButtonActive.mBg;
+      break;
+    case ColorID::MozButtonactivetext:
+      aColor = mButtonActive.mFg;
+      break;
+    case ColorID::MozMenuhover:
+      aColor = mMenuHover.mBg;
+      break;
+    case ColorID::MozMenuhovertext:
+      aColor = mMenuHover.mFg;
+      break;
+    case ColorID::MozMenuhoverdisabled:
+      aColor = NS_TRANSPARENT;
+      break;
+    case ColorID::MozOddtreerow:
+      aColor = mOddCellBackground;
+      break;
+    case ColorID::MozNativehyperlinktext:
+      aColor = mNativeHyperLinkText;
+      break;
+    case ColorID::MozNativevisitedhyperlinktext:
+      aColor = mNativeVisitedHyperLinkText;
+      break;
+    case ColorID::MozComboboxtext:
+      aColor = mComboBoxText;
+      break;
+    case ColorID::MozColheader:
+      aColor = mMozColHeader.mBg;
+      break;
+    case ColorID::MozColheadertext:
+      aColor = mMozColHeader.mFg;
+      break;
+    case ColorID::MozColheaderhover:
+      aColor = mMozColHeaderHover.mBg;
+      break;
+    case ColorID::MozColheaderhovertext:
+      aColor = mMozColHeaderHover.mFg;
+      break;
+    case ColorID::MozColheaderactive:
+      aColor = mMozColHeaderActive.mBg;
+      break;
+    case ColorID::MozColheaderactivetext:
+      aColor = mMozColHeaderActive.mFg;
+      break;
+    case ColorID::SpellCheckerUnderline:
+    case ColorID::Mark:
+    case ColorID::Marktext:
+      aColor = GetStandinForNativeColor(
+          aID, mIsDark ? ColorScheme::Dark : ColorScheme::Light);
+      break;
+    default:
+      /* default color is BLACK */
+      aColor = 0;
+      res = NS_ERROR_FAILURE;
+      break;
+  }
+
+  return res;
+}
+
+static int32_t CheckWidgetStyle(GtkWidget* aWidget, const char* aStyle,
+                                int32_t aResult) {
+  gboolean value = FALSE;
+  gtk_widget_style_get(aWidget, aStyle, &value, nullptr);
+  return value ? aResult : 0;
+}
+
+static int32_t ConvertGTKStepperStyleToMozillaScrollArrowStyle(
+    GtkWidget* aWidget) {
+  if (!aWidget) return mozilla::LookAndFeel::eScrollArrowStyle_Single;
+
+  return CheckWidgetStyle(aWidget, "has-backward-stepper",
+                          mozilla::LookAndFeel::eScrollArrow_StartBackward) |
+         CheckWidgetStyle(aWidget, "has-forward-stepper",
+                          mozilla::LookAndFeel::eScrollArrow_EndForward) |
+         CheckWidgetStyle(aWidget, "has-secondary-backward-stepper",
+                          mozilla::LookAndFeel::eScrollArrow_EndBackward) |
+         CheckWidgetStyle(aWidget, "has-secondary-forward-stepper",
+                          mozilla::LookAndFeel::eScrollArrow_StartForward);
+}
+
+nsresult nsLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
+  nsresult res = NS_OK;
+
+  // We use delayed initialization by EnsureInit() here
+  // to make sure mozilla::Preferences is available (Bug 115807).
+  // IntID::UseAccessibilityTheme is requested before user preferences
+  // are read, and so EnsureInit(), which depends on preference values,
+  // is deliberately delayed until required.
+  switch (aID) {
+    case IntID::ScrollButtonLeftMouseButtonAction:
+      aResult = 0;
+      break;
+    case IntID::ScrollButtonMiddleMouseButtonAction:
+      aResult = 1;
+      break;
+    case IntID::ScrollButtonRightMouseButtonAction:
+      aResult = 2;
+      break;
+    case IntID::CaretBlinkTime:
+      EnsureInit();
+      aResult = mCaretBlinkTime;
+      break;
+    case IntID::CaretBlinkCount:
+      EnsureInit();
+      aResult = mCaretBlinkCount;
+      break;
+    case IntID::CaretWidth:
+      aResult = 1;
+      break;
+    case IntID::ShowCaretDuringSelection:
+      aResult = 0;
+      break;
+    case IntID::SelectTextfieldsOnKeyFocus: {
+      GtkSettings* settings;
+      gboolean select_on_focus;
+
+      settings = gtk_settings_get_default();
+      g_object_get(settings, "gtk-entry-select-on-focus", &select_on_focus,
+                   nullptr);
+
+      if (select_on_focus)
+        aResult = 1;
+      else
+        aResult = 0;
+
+    } break;
+    case IntID::ScrollToClick: {
+      GtkSettings* settings;
+      gboolean warps_slider = FALSE;
+
+      settings = gtk_settings_get_default();
+      if (g_object_class_find_property(G_OBJECT_GET_CLASS(settings),
+                                       "gtk-primary-button-warps-slider")) {
+        g_object_get(settings, "gtk-primary-button-warps-slider", &warps_slider,
+                     nullptr);
+      }
+
+      if (warps_slider)
+        aResult = 1;
+      else
+        aResult = 0;
+    } break;
+    case IntID::SubmenuDelay: {
+      GtkSettings* settings;
+      gint delay;
+
+      settings = gtk_settings_get_default();
+      g_object_get(settings, "gtk-menu-popup-delay", &delay, nullptr);
+      aResult = (int32_t)delay;
+      break;
+    }
+    case IntID::TooltipDelay: {
+      aResult = 500;
+      break;
+    }
+    case IntID::MenusCanOverlapOSBar:
+      // we want XUL popups to be able to overlap the task bar.
+      aResult = 1;
+      break;
+    case IntID::SkipNavigatingDisabledMenuItem:
+      aResult = 1;
+      break;
+    case IntID::DragThresholdX:
+    case IntID::DragThresholdY: {
+      gint threshold = 0;
+      g_object_get(gtk_settings_get_default(), "gtk-dnd-drag-threshold",
+                   &threshold, nullptr);
+
+      aResult = threshold;
+    } break;
+    case IntID::ScrollArrowStyle: {
+      GtkWidget* scrollbar = GetWidget(MOZ_GTK_SCROLLBAR_VERTICAL);
+      aResult = ConvertGTKStepperStyleToMozillaScrollArrowStyle(scrollbar);
+      break;
+    }
+    case IntID::TreeOpenDelay:
+      aResult = 1000;
+      break;
+    case IntID::TreeCloseDelay:
+      aResult = 1000;
+      break;
+    case IntID::TreeLazyScrollDelay:
+      aResult = 150;
+      break;
+    case IntID::TreeScrollDelay:
+      aResult = 100;
+      break;
+    case IntID::TreeScrollLinesMax:
+      aResult = 3;
+      break;
+    case IntID::AlertNotificationOrigin:
+      aResult = NS_ALERT_TOP;
+      break;
+    case IntID::IMERawInputUnderlineStyle:
+    case IntID::IMEConvertedTextUnderlineStyle:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Solid);
+      break;
+    case IntID::IMESelectedRawTextUnderlineStyle:
+    case IntID::IMESelectedConvertedTextUnderline:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::None);
+      break;
+    case IntID::SpellCheckerUnderlineStyle:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Wavy);
+      break;
+    case IntID::MenuBarDrag:
+      EnsureInit();
+      aResult = mSystemTheme.mMenuSupportsDrag;
+      break;
+    case IntID::ScrollbarButtonAutoRepeatBehavior:
+      aResult = 1;
+      break;
+    case IntID::SwipeAnimationEnabled:
+      aResult = 1;
+      break;
+    case IntID::ContextMenuOffsetVertical:
+    case IntID::ContextMenuOffsetHorizontal:
+      aResult = 2;
+      break;
+    case IntID::GTKCSDAvailable:
+      aResult = sCSDAvailable;
+      break;
+    case IntID::GTKCSDMaximizeButton:
+      EnsureInit();
+      aResult = mCSDMaximizeButton;
+      break;
+    case IntID::GTKCSDMinimizeButton:
+      EnsureInit();
+      aResult = mCSDMinimizeButton;
+      break;
+    case IntID::GTKCSDCloseButton:
+      EnsureInit();
+      aResult = mCSDCloseButton;
+      break;
+    case IntID::GTKCSDReversedPlacement:
+      EnsureInit();
+      aResult = mCSDReversedPlacement;
+      break;
+    case IntID::PrefersReducedMotion: {
+      EnsureInit();
+      aResult = mPrefersReducedMotion;
+      break;
+    }
+    case IntID::SystemUsesDarkTheme: {
+      EnsureInit();
+      if (mColorSchemePreference) {
+        aResult = *mColorSchemePreference == ColorScheme::Dark;
+      } else {
+        aResult = mSystemTheme.mIsDark;
+      }
+      break;
+    }
+    case IntID::GTKCSDMaximizeButtonPosition:
+      aResult = mCSDMaximizeButtonPosition;
+      break;
+    case IntID::GTKCSDMinimizeButtonPosition:
+      aResult = mCSDMinimizeButtonPosition;
+      break;
+    case IntID::GTKCSDCloseButtonPosition:
+      aResult = mCSDCloseButtonPosition;
+      break;
+    case IntID::GTKThemeFamily: {
+      EnsureInit();
+      aResult = int32_t(EffectiveTheme().mFamily);
+      break;
+    }
+    case IntID::UseAccessibilityTheme:
+    // If high contrast is enabled, enable prefers-reduced-transparency media
+    // query as well as there is no dedicated option.
+    case IntID::PrefersReducedTransparency:
+      EnsureInit();
+      aResult = mSystemTheme.mHighContrast;
+      break;
+    case IntID::InvertedColors:
+      // No GTK API for checking if inverted colors is enabled
+      aResult = 0;
+      break;
+    case IntID::TitlebarRadius: {
+      EnsureInit();
+      aResult = EffectiveTheme().mTitlebarRadius;
+      break;
+    }
+    case IntID::AllowOverlayScrollbarsOverlap: {
+      aResult = 1;
+      break;
+    }
+    case IntID::ScrollbarFadeBeginDelay: {
+      aResult = 1000;
+      break;
+    }
+    case IntID::ScrollbarFadeDuration: {
+      aResult = 400;
+      break;
+    }
+    case IntID::ScrollbarDisplayOnMouseMove: {
+      aResult = 1;
+      break;
+    }
+    case IntID::PanelAnimations:
+      aResult = [&]() -> bool {
+        if (!sCSDAvailable) {
+          // Disabled on systems without CSD, see bug 1385079.
+          return false;
+        }
+        if (GdkIsWaylandDisplay()) {
+          // Disabled on wayland, see bug 1800442 and bug 1800368.
+          return false;
+        }
+        return true;
+      }();
+      break;
+    case IntID::UseOverlayScrollbars: {
+      aResult = StaticPrefs::widget_gtk_overlay_scrollbars_enabled();
+      break;
+    }
+    case IntID::HideCursorWhileTyping: {
+      aResult = StaticPrefs::widget_gtk_hide_pointer_while_typing_enabled();
+      break;
+    }
+    case IntID::TouchDeviceSupportPresent:
+      aResult = widget::WidgetUtilsGTK::IsTouchDeviceSupportPresent();
+      break;
+    default:
+      aResult = 0;
+      res = NS_ERROR_FAILURE;
+  }
+
+  return res;
+}
+
+nsresult nsLookAndFeel::NativeGetFloat(FloatID aID, float& aResult) {
+  nsresult rv = NS_OK;
+  switch (aID) {
+    case FloatID::IMEUnderlineRelativeSize:
+      aResult = 1.0f;
+      break;
+    case FloatID::SpellCheckerUnderlineRelativeSize:
+      aResult = 1.0f;
+      break;
+    case FloatID::CaretAspectRatio:
+      EnsureInit();
+      aResult = mSystemTheme.mCaretRatio;
+      break;
+    case FloatID::TextScaleFactor:
+      aResult = gfxPlatformGtk::GetFontScaleFactor();
+      break;
+    default:
+      aResult = -1.0;
+      rv = NS_ERROR_FAILURE;
+  }
+  return rv;
+}
+
+static void GetSystemFontInfo(GtkStyleContext* aStyle, nsString* aFontName,
+                              gfxFontStyle* aFontStyle) {
+  aFontStyle->style = FontSlantStyle::NORMAL;
+
+  // As in
+  // https://git.gnome.org/browse/gtk+/tree/gtk/gtkwidget.c?h=3.22.19#n10333
+  PangoFontDescription* desc;
+  gtk_style_context_get(aStyle, gtk_style_context_get_state(aStyle), "font",
+                        &desc, nullptr);
+
+  aFontStyle->systemFont = true;
+
+  constexpr auto quote = u"\""_ns;
+  NS_ConvertUTF8toUTF16 family(pango_font_description_get_family(desc));
+  *aFontName = quote + family + quote;
+
+  aFontStyle->weight =
+      FontWeight::FromInt(pango_font_description_get_weight(desc));
+
+  // FIXME: Set aFontStyle->stretch correctly!
+  aFontStyle->stretch = FontStretch::NORMAL;
+
+  float size = float(pango_font_description_get_size(desc)) / PANGO_SCALE;
+
+  // |size| is now either pixels or pango-points (not Mozilla-points!)
+
+  if (!pango_font_description_get_size_is_absolute(desc)) {
+    // |size| is in pango-points, so convert to pixels.
+    size *= float(gfxPlatformGtk::GetFontScaleDPI()) / POINTS_PER_INCH_FLOAT;
+  }
+
+  // |size| is now pixels but not scaled for the hidpi displays,
+  aFontStyle->size = size;
+
+  pango_font_description_free(desc);
+}
+
+bool nsLookAndFeel::NativeGetFont(FontID aID, nsString& aFontName,
+                                  gfxFontStyle& aFontStyle) {
+  return mSystemTheme.GetFont(aID, aFontName, aFontStyle);
+}
+
+bool nsLookAndFeel::PerThemeData::GetFont(FontID aID, nsString& aFontName,
+                                          gfxFontStyle& aFontStyle) const {
+  switch (aID) {
+    case FontID::Menu:             // css2
+    case FontID::MozPullDownMenu:  // css3
+      aFontName = mMenuFontName;
+      aFontStyle = mMenuFontStyle;
+      break;
+
+    case FontID::MozField:  // css3
+    case FontID::MozList:   // css3
+      aFontName = mFieldFontName;
+      aFontStyle = mFieldFontStyle;
+      break;
+
+    case FontID::MozButton:  // css3
+      aFontName = mButtonFontName;
+      aFontStyle = mButtonFontStyle;
+      break;
+
+    case FontID::Caption:       // css2
+    case FontID::Icon:          // css2
+    case FontID::MessageBox:    // css2
+    case FontID::SmallCaption:  // css2
+    case FontID::StatusBar:     // css2
+    default:
+      aFontName = mDefaultFontName;
+      aFontStyle = mDefaultFontStyle;
+      break;
+  }
+
+  // Convert GDK pixels to CSS pixels.
+  // When "layout.css.devPixelsPerPx" > 0, this is not a direct conversion.
+  // The difference produces a scaling of system fonts in proportion with
+  // other scaling from the change in CSS pixel sizes.
+  aFontStyle.size /= LookAndFeel::GetTextScaleFactor();
+  return true;
+}
+
+static nsCString GetGtkSettingsStringKey(const char* aKey) {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  nsCString ret;
+  GtkSettings* settings = gtk_settings_get_default();
+  char* value = nullptr;
+  g_object_get(settings, aKey, &value, nullptr);
+  if (value) {
+    ret.Assign(value);
+    g_free(value);
+  }
+  return ret;
+}
+
+static nsCString GetGtkTheme() {
+  return GetGtkSettingsStringKey("gtk-theme-name");
+}
+
+static bool GetPreferDarkTheme() {
+  GtkSettings* settings = gtk_settings_get_default();
+  gboolean preferDarkTheme = FALSE;
+  g_object_get(settings, "gtk-application-prefer-dark-theme", &preferDarkTheme,
+               nullptr);
+  return preferDarkTheme == TRUE;
+}
+
+// It seems GTK doesn't have an API to query if the current theme is "light" or
+// "dark", so we synthesize it from the CSS2 Window/WindowText colors instead,
+// by comparing their luminosity.
+static bool GetThemeIsDark() {
+  GdkRGBA bg, fg;
+  GtkStyleContext* style = GetStyleContext(MOZ_GTK_WINDOW);
+  gtk_style_context_get_background_color(style, GTK_STATE_FLAG_NORMAL, &bg);
+  gtk_style_context_get_color(style, GTK_STATE_FLAG_NORMAL, &fg);
+  return RelativeLuminanceUtils::Compute(GDK_RGBA_TO_NS_RGBA(bg)) <
+         RelativeLuminanceUtils::Compute(GDK_RGBA_TO_NS_RGBA(fg));
+}
+
+void nsLookAndFeel::RestoreSystemTheme() {
+  LOGLNF("RestoreSystemTheme(%s, %d, %d)\n", mSystemTheme.mName.get(),
+         mSystemTheme.mPreferDarkTheme, mSystemThemeOverridden);
+
+  if (!mSystemThemeOverridden) {
+    return;
+  }
+
+  // Available on Gtk 3.20+.
+  static auto sGtkSettingsResetProperty =
+      (void (*)(GtkSettings*, const gchar*))dlsym(
+          RTLD_DEFAULT, "gtk_settings_reset_property");
+
+  GtkSettings* settings = gtk_settings_get_default();
+  if (sGtkSettingsResetProperty) {
+    sGtkSettingsResetProperty(settings, "gtk-theme-name");
+    sGtkSettingsResetProperty(settings, "gtk-application-prefer-dark-theme");
+  } else {
+    g_object_set(settings, "gtk-theme-name", mSystemTheme.mName.get(),
+                 "gtk-application-prefer-dark-theme",
+                 mSystemTheme.mPreferDarkTheme, nullptr);
+  }
+  mSystemThemeOverridden = false;
+  UpdateRoundedBottomCornerStyles();
+  moz_gtk_refresh();
+}
+
+static bool AnyColorChannelIsDifferent(nscolor aColor) {
+  return NS_GET_R(aColor) != NS_GET_G(aColor) ||
+         NS_GET_R(aColor) != NS_GET_B(aColor);
+}
+
+bool nsLookAndFeel::ConfigureAltTheme() {
+  GtkSettings* settings = gtk_settings_get_default();
+  // Toggling gtk-application-prefer-dark-theme is not enough generally to
+  // switch from dark to light theme.  If the theme didn't change, and we have
+  // a dark theme, try to first remove -Dark{,er,est} from the theme name to
+  // find the light variant.
+  if (mSystemTheme.mIsDark) {
+    nsCString potentialLightThemeName = mSystemTheme.mName;
+    // clang-format off
+    constexpr nsLiteralCString kSubstringsToRemove[] = {
+        "-darkest"_ns, "-darker"_ns, "-dark"_ns,
+        "-Darkest"_ns, "-Darker"_ns, "-Dark"_ns,
+        "_darkest"_ns, "_darker"_ns, "_dark"_ns,
+        "_Darkest"_ns, "_Darker"_ns, "_Dark"_ns,
+    };
+    // clang-format on
+    bool found = false;
+    for (const auto& s : kSubstringsToRemove) {
+      potentialLightThemeName = mSystemTheme.mName;
+      potentialLightThemeName.ReplaceSubstring(s, ""_ns);
+      if (potentialLightThemeName.Length() != mSystemTheme.mName.Length()) {
+        found = true;
+        break;
+      }
+    }
+    if (found) {
+      LOGLNF("    found potential light variant of %s: %s",
+             mSystemTheme.mName.get(), potentialLightThemeName.get());
+      g_object_set(settings, "gtk-theme-name", potentialLightThemeName.get(),
+                   "gtk-application-prefer-dark-theme", !mSystemTheme.mIsDark,
+                   nullptr);
+      moz_gtk_refresh();
+
+      if (!GetThemeIsDark()) {
+        return true;  // Success!
+      }
+    }
+  }
+
+  LOGLNF("    toggling gtk-application-prefer-dark-theme");
+  g_object_set(settings, "gtk-application-prefer-dark-theme",
+               !mSystemTheme.mIsDark, nullptr);
+  moz_gtk_refresh();
+  if (mSystemTheme.mIsDark != GetThemeIsDark()) {
+    return true;  // Success!
+  }
+
+  LOGLNF("    didn't work, falling back to default theme");
+  // If the theme still didn't change enough, fall back to Adwaita with the
+  // appropriate color preference.
+  g_object_set(settings, "gtk-theme-name", "Adwaita",
+               "gtk-application-prefer-dark-theme", !mSystemTheme.mIsDark,
+               nullptr);
+  moz_gtk_refresh();
+
+  // If it _still_ didn't change enough, and we're looking for a dark theme,
+  // try to set Adwaita-dark as a theme name. This might be needed in older GTK
+  // versions.
+  if (!mSystemTheme.mIsDark && !GetThemeIsDark()) {
+    LOGLNF("    last resort Adwaita-dark fallback");
+    g_object_set(settings, "gtk-theme-name", "Adwaita-dark", nullptr);
+    moz_gtk_refresh();
+  }
+
+  return false;
+}
+
+// We override some adwaita colors from GTK3 to LibAdwaita, see:
+// https://gnome.pages.gitlab.gnome.org/libadwaita/doc/main/named-colors.html
+void nsLookAndFeel::MaybeApplyAdwaitaOverrides() {
+  auto& dark = mSystemTheme.mIsDark ? mSystemTheme : mAltTheme;
+  auto& light = mSystemTheme.mIsDark ? mAltTheme : mSystemTheme;
+
+  // Unconditional special case for Adwaita-dark: In GTK3 we don't have more
+  // proper accent colors, so we use the selected background colors. Those
+  // colors, however, don't have much contrast in dark mode (see bug 1741293).
+  if (dark.mFamily == ThemeFamily::Adwaita) {
+    dark.mAccent = {NS_RGB(0x35, 0x84, 0xe4), NS_RGB(0xff, 0xff, 0xff)};
+    dark.mSelectedText = dark.mAccent;
+  }
+
+  if (light.mFamily == ThemeFamily::Adwaita) {
+    light.mAccent = {NS_RGB(0x35, 0x84, 0xe4), NS_RGB(0xff, 0xff, 0xff)};
+    light.mSelectedText = light.mAccent;
+  }
+
+  if (!StaticPrefs::widget_gtk_libadwaita_colors_enabled()) {
+    return;
+  }
+
+  if (light.mFamily == ThemeFamily::Adwaita) {
+    // #323232 is rgba(0,0,0,.8) over #fafafa.
+    light.mWindow =
+        light.mDialog = {NS_RGB(0xfa, 0xfa, 0xfa), NS_RGB(0x32, 0x32, 0x32)};
+    light.mField = {NS_RGB(0xff, 0xff, 0xff), NS_RGB(0x32, 0x32, 0x32)};
+
+    // We use the sidebar colors for the headerbar in light mode background
+    // because it creates much better contrast. GTK headerbar colors are white,
+    // and meant to "blend" with the contents otherwise.
+    // #2f2f2f is rgba(0,0,0,.8) over #ebebeb.
+    light.mSidebar = light.mHeaderBar =
+        light.mTitlebar = {NS_RGB(0xeb, 0xeb, 0xeb), NS_RGB(0x2f, 0x2f, 0x2f)};
+    light.mHeaderBarInactive = light.mTitlebarInactive = {
+        NS_RGB(0xf2, 0xf2, 0xf2), NS_RGB(0x2f, 0x2f, 0x2f)};
+    light.mThreeDShadow = NS_RGB(0xe0, 0xe0, 0xe0);
+    light.mSidebarBorder = NS_RGBA(0, 0, 0, 18);
+  }
+
+  if (dark.mFamily == ThemeFamily::Adwaita) {
+    dark.mWindow = {NS_RGB(0x24, 0x24, 0x24), NS_RGB(0xff, 0xff, 0xff)};
+    dark.mDialog = {NS_RGB(0x38, 0x38, 0x38), NS_RGB(0xff, 0xff, 0xff)};
+    dark.mField = {NS_RGB(0x3a, 0x3a, 0x3a), NS_RGB(0xff, 0xff, 0xff)};
+    dark.mSidebar = dark.mHeaderBar =
+        dark.mTitlebar = {NS_RGB(0x30, 0x30, 0x30), NS_RGB(0xff, 0xff, 0xff)};
+    dark.mHeaderBarInactive = dark.mTitlebarInactive = {
+        NS_RGB(0x24, 0x24, 0x24), NS_RGB(0xff, 0xff, 0xff)};
+    // headerbar_shade_color
+    dark.mThreeDShadow = NS_RGB(0x1f, 0x1f, 0x1f);
+    dark.mSidebarBorder = NS_RGBA(0, 0, 0, 92);
+  }
+}
+
+void nsLookAndFeel::ConfigureAndInitializeAltTheme() {
+  const bool fellBackToDefaultTheme = !ConfigureAltTheme();
+
+  mAltTheme.Init();
+
+  MaybeApplyAdwaitaOverrides();
+
+  // Some of the alt theme colors we can grab from the system theme, if we fell
+  // back to the default light / dark themes.
+  if (fellBackToDefaultTheme) {
+    if (StaticPrefs::widget_gtk_alt_theme_selection()) {
+      mAltTheme.mSelectedText = mSystemTheme.mSelectedText;
+    }
+
+    if (StaticPrefs::widget_gtk_alt_theme_scrollbar_active() &&
+        (!mAltTheme.mIsDark || ShouldUseColorForActiveDarkScrollbarThumb(
+                                   mSystemTheme.mThemedScrollbarThumbActive))) {
+      mAltTheme.mThemedScrollbarThumbActive =
+          mSystemTheme.mThemedScrollbarThumbActive;
+    }
+
+    if (StaticPrefs::widget_gtk_alt_theme_accent()) {
+      mAltTheme.mAccent = mSystemTheme.mAccent;
+    }
+  }
+
+  // Right now we're using the opposite color-scheme theme, make sure to record
+  // it.
+  mSystemThemeOverridden = true;
+  UpdateRoundedBottomCornerStyles();
+}
+
+void nsLookAndFeel::ClearRoundedCornerProvider() {
+  if (mRoundedCornerProvider) {
+    gtk_style_context_remove_provider_for_screen(
+        gdk_screen_get_default(),
+        GTK_STYLE_PROVIDER(mRoundedCornerProvider.get()));
+    mRoundedCornerProvider = nullptr;
+  }
+}
+
+void nsLookAndFeel::UpdateRoundedBottomCornerStyles() {
+  ClearRoundedCornerProvider();
+  if (!StaticPrefs::widget_gtk_rounded_bottom_corners_enabled()) {
+    return;
+  }
+  int32_t radius = EffectiveTheme().mTitlebarRadius;
+  if (!radius) {
+    return;
+  }
+  mRoundedCornerProvider = dont_AddRef(gtk_css_provider_new());
+  nsPrintfCString string(
+      "window.csd decoration {"
+      "border-bottom-right-radius: %dpx;"
+      "border-bottom-left-radius: %dpx;"
+      "}\n",
+      radius, radius);
+  GUniquePtr<GError> error;
+  if (!gtk_css_provider_load_from_data(mRoundedCornerProvider.get(),
+                                       string.get(), string.Length(),
+                                       getter_Transfers(error))) {
+    NS_WARNING(nsPrintfCString("Failed to load provider: %s - %s\n",
+                               string.get(), error ? error->message : nullptr)
+                   .get());
+  }
+  gtk_style_context_add_provider_for_screen(
+      gdk_screen_get_default(),
+      GTK_STYLE_PROVIDER(mRoundedCornerProvider.get()),
+      GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
+}
+
+Maybe<ColorScheme> nsLookAndFeel::ComputeColorSchemeSetting() {
+  {
+    // Check the pref explicitly here. Usually this shouldn't be needed, but
+    // since we can only load one GTK theme at a time, and the pref will
+    // override the effective value that the rest of gecko assumes for the
+    // "system" color scheme, we need to factor it in our GTK theme decisions.
+    int32_t pref = 0;
+    if (NS_SUCCEEDED(Preferences::GetInt("ui.systemUsesDarkTheme", &pref))) {
+      return Some(pref ? ColorScheme::Dark : ColorScheme::Light);
+    }
+  }
+
+  if (!mDBusSettingsProxy) {
+    return Nothing();
+  }
+  GUniquePtr<GError> error;
+  RefPtr<GVariant> variant = dont_AddRef(g_dbus_proxy_call_sync(
+      mDBusSettingsProxy, "Read",
+      g_variant_new("(ss)", "org.freedesktop.appearance", "color-scheme"),
+      G_DBUS_CALL_FLAGS_NONE,
+      StaticPrefs::widget_gtk_settings_portal_timeout_ms(), nullptr,
+      getter_Transfers(error)));
+  if (!variant) {
+    LOGLNF("color-scheme query error: %s\n", error->message);
+    return Nothing();
+  }
+  LOGLNF("color-scheme query result: %s\n", GVariantToString(variant).get());
+  variant = dont_AddRef(g_variant_get_child_value(variant, 0));
+  while (variant && g_variant_is_of_type(variant, G_VARIANT_TYPE_VARIANT)) {
+    // Unbox the return value.
+    variant = dont_AddRef(g_variant_get_variant(variant));
+  }
+  if (!variant || !g_variant_is_of_type(variant, G_VARIANT_TYPE_UINT32)) {
+    MOZ_ASSERT(false, "Unexpected color-scheme query return value");
+    return Nothing();
+  }
+  switch (g_variant_get_uint32(variant)) {
+    default:
+      MOZ_FALLTHROUGH_ASSERT("Unexpected color-scheme query return value");
+    case 0:
+      break;
+    case 1:
+      return Some(ColorScheme::Dark);
+    case 2:
+      return Some(ColorScheme::Light);
+  }
+  return Nothing();
+}
+
+void nsLookAndFeel::Initialize() {
+  LOGLNF("nsLookAndFeel::Initialize");
+  MOZ_DIAGNOSTIC_ASSERT(!mInitialized);
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread(),
+                        "LookAndFeel init should be done on the main thread");
+
+  mInitialized = true;
+
+  GtkSettings* settings = gtk_settings_get_default();
+  if (MOZ_UNLIKELY(!settings)) {
+    NS_WARNING("EnsureInit: No settings");
+    return;
+  }
+
+  AutoRestore<bool> restoreIgnoreSettings(sIgnoreChangedSettings);
+  sIgnoreChangedSettings = true;
+
+  // Our current theme may be different from the system theme if we're matching
+  // the Firefox theme or using the alt theme intentionally due to the
+  // color-scheme preference. Make sure to restore the original system theme.
+  RestoreSystemTheme();
+
+  // First initialize global settings.
+  InitializeGlobalSettings();
+
+  // Record our system theme settings now.
+  mSystemTheme.Init();
+
+  // Find the alternative-scheme theme (light if the system theme is dark, or
+  // vice versa), configure it and initialize it.
+  ConfigureAndInitializeAltTheme();
+
+  LOGLNF("System Theme: %s. Alt Theme: %s\n", mSystemTheme.mName.get(),
+         mAltTheme.mName.get());
+
+  // Go back to the system theme or keep the alt theme configured, depending on
+  // Firefox theme or user color-scheme preference.
+  ConfigureFinalEffectiveTheme();
+
+  RecordTelemetry();
+}
+
+void nsLookAndFeel::OnColorSchemeSettingChanged() {
+  if (NS_WARN_IF(mColorSchemePreference == ComputeColorSchemeSetting())) {
+    // We sometimes get duplicate color-scheme changes from dbus, avoid doing
+    // extra work if not needed.
+    return;
+  }
+  OnSettingsChange();
+}
+
+void nsLookAndFeel::InitializeGlobalSettings() {
+  GtkSettings* settings = gtk_settings_get_default();
+
+  mColorSchemePreference = ComputeColorSchemeSetting();
+
+  gboolean enableAnimations = false;
+  g_object_get(settings, "gtk-enable-animations", &enableAnimations, nullptr);
+  mPrefersReducedMotion = !enableAnimations;
+
+  gint blink_time = 0;     // In milliseconds
+  gint blink_timeout = 0;  // in seconds
+  gboolean blink;
+  g_object_get(settings, "gtk-cursor-blink-time", &blink_time,
+               "gtk-cursor-blink-timeout", &blink_timeout, "gtk-cursor-blink",
+               &blink, nullptr);
+  // From
+  // https://docs.gtk.org/gtk3/property.Settings.gtk-cursor-blink-timeout.html:
+  //
+  //     Setting this to zero has the same effect as setting
+  //     GtkSettings:gtk-cursor-blink to FALSE.
+  //
+  mCaretBlinkTime = blink && blink_timeout ? (int32_t)blink_time : 0;
+
+  if (mCaretBlinkTime) {
+    // blink_time * 2 because blink count is a full blink cycle.
+    mCaretBlinkCount =
+        std::max(1, int32_t(std::ceil(float(blink_timeout * 1000) /
+                                      (float(blink_time) * 2.0f))));
+  } else {
+    mCaretBlinkCount = -1;
+  }
+
+  mCSDCloseButton = false;
+  mCSDMinimizeButton = false;
+  mCSDMaximizeButton = false;
+  mCSDCloseButtonPosition = 0;
+  mCSDMinimizeButtonPosition = 0;
+  mCSDMaximizeButtonPosition = 0;
+
+  // We need to initialize whole CSD config explicitly because it's queried
+  // as -moz-gtk* media features.
+  ButtonLayout buttonLayout[TOOLBAR_BUTTONS];
+
+  size_t activeButtons =
+      GetGtkHeaderBarButtonLayout(Span(buttonLayout), &mCSDReversedPlacement);
+  for (size_t i = 0; i < activeButtons; i++) {
+    // We check if a button is represented on the right side of the tabbar.
+    // Then we assign it a value from 3 to 5, instead of 0 to 2 when it is on
+    // the left side.
+    const ButtonLayout& layout = buttonLayout[i];
+    int32_t* pos = nullptr;
+    switch (layout.mType) {
+      case MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE:
+        mCSDMinimizeButton = true;
+        pos = &mCSDMinimizeButtonPosition;
+        break;
+      case MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE:
+        mCSDMaximizeButton = true;
+        pos = &mCSDMaximizeButtonPosition;
+        break;
+      case MOZ_GTK_HEADER_BAR_BUTTON_CLOSE:
+        mCSDCloseButton = true;
+        pos = &mCSDCloseButtonPosition;
+        break;
+      default:
+        break;
+    }
+
+    if (pos) {
+      *pos = i;
+    }
+  }
+
+  struct actionMapping {
+    TitlebarAction action;
+    char name[100];
+  } ActionMapping[] = {
+      {TitlebarAction::None, "none"},
+      {TitlebarAction::WindowLower, "lower"},
+      {TitlebarAction::WindowMenu, "menu"},
+      {TitlebarAction::WindowMinimize, "minimize"},
+      {TitlebarAction::WindowMaximize, "maximize"},
+      {TitlebarAction::WindowMaximizeToggle, "toggle-maximize"},
+  };
+
+  auto GetWindowAction = [&](const char* eventName) -> TitlebarAction {
+    gchar* action = nullptr;
+    g_object_get(settings, eventName, &action, nullptr);
+    if (!action) {
+      return TitlebarAction::None;
+    }
+    auto free = mozilla::MakeScopeExit([&] { g_free(action); });
+    for (auto const& mapping : ActionMapping) {
+      if (!strncmp(action, mapping.name, strlen(mapping.name))) {
+        return mapping.action;
+      }
+    }
+    return TitlebarAction::None;
+  };
+
+  mDoubleClickAction = GetWindowAction("gtk-titlebar-double-click");
+  mMiddleClickAction = GetWindowAction("gtk-titlebar-middle-click");
+}
+
+void nsLookAndFeel::ConfigureFinalEffectiveTheme() {
+  MOZ_ASSERT(mSystemThemeOverridden,
+             "By this point, the alt theme should be configured");
+  const bool shouldUseSystemTheme = [&] {
+    using ChromeSetting = PreferenceSheet::ChromeColorSchemeSetting;
+    // NOTE: We can't call ColorSchemeForChrome directly because this might run
+    // while we're computing it.
+    switch (PreferenceSheet::ColorSchemeSettingForChrome()) {
+      case ChromeSetting::Light:
+        return !mSystemTheme.mIsDark;
+      case ChromeSetting::Dark:
+        return mSystemTheme.mIsDark;
+      case ChromeSetting::System:
+        break;
+    };
+    if (!mColorSchemePreference) {
+      return true;
+    }
+    const bool preferenceIsDark = *mColorSchemePreference == ColorScheme::Dark;
+    return preferenceIsDark == mSystemTheme.mIsDark;
+  }();
+
+  const bool usingSystem = !mSystemThemeOverridden;
+  LOGLNF("OverrideSystemThemeIfNeeded(matchesSystem=%d, usingSystem=%d)\n",
+         shouldUseSystemTheme, usingSystem);
+
+  if (shouldUseSystemTheme) {
+    RestoreSystemTheme();
+  } else if (usingSystem) {
+    LOGLNF("Setting theme %s, %d\n", mAltTheme.mName.get(),
+           mAltTheme.mPreferDarkTheme);
+
+    GtkSettings* settings = gtk_settings_get_default();
+    if (mSystemTheme.mName == mAltTheme.mName) {
+      // Prefer setting only gtk-application-prefer-dark-theme, so we can still
+      // get notified from notify::gtk-theme-name if the user changes the theme.
+      g_object_set(settings, "gtk-application-prefer-dark-theme",
+                   mAltTheme.mPreferDarkTheme, nullptr);
+    } else {
+      g_object_set(settings, "gtk-theme-name", mAltTheme.mName.get(),
+                   "gtk-application-prefer-dark-theme",
+                   mAltTheme.mPreferDarkTheme, nullptr);
+    }
+    mSystemThemeOverridden = true;
+    UpdateRoundedBottomCornerStyles();
+    moz_gtk_refresh();
+  }
+}
+
+static bool GetColorFromBackgroundImage(GtkStyleContext* aStyle,
+                                        nscolor aForForegroundColor,
+                                        GtkStateFlags aState, nscolor* aColor) {
+  GValue value = G_VALUE_INIT;
+  gtk_style_context_get_property(aStyle, "background-image", aState, &value);
+  auto cleanup = MakeScopeExit([&] { g_value_unset(&value); });
+  if (GetColorFromImagePattern(&value, aColor)) {
+    return true;
+  }
+
+  {
+    GdkRGBA light, dark;
+    if (GetGradientColors(&value, &light, &dark)) {
+      nscolor l = GDK_RGBA_TO_NS_RGBA(light);
+      nscolor d = GDK_RGBA_TO_NS_RGBA(dark);
+      // Return the one with more contrast.
+      // TODO(emilio): This could do interpolation or what not but seems
+      // overkill.
+      if (NS_LUMINOSITY_DIFFERENCE(l, aForForegroundColor) >
+          NS_LUMINOSITY_DIFFERENCE(d, aForForegroundColor)) {
+        *aColor = l;
+      } else {
+        *aColor = d;
+      }
+      return true;
+    }
+  }
+
+  return false;
+}
+
+static nscolor GetBackgroundColor(
+    GtkStyleContext* aStyle, nscolor aForForegroundColor,
+    GtkStateFlags aState = GTK_STATE_FLAG_NORMAL,
+    nscolor aOverBackgroundColor = NS_TRANSPARENT) {
+  // Try to synthesize a color from a background-image.
+  nscolor imageColor = NS_TRANSPARENT;
+  if (GetColorFromBackgroundImage(aStyle, aForForegroundColor, aState,
+                                  &imageColor)) {
+    if (NS_GET_A(imageColor) == 255) {
+      return imageColor;
+    }
+  }
+
+  GdkRGBA gdkColor;
+  gtk_style_context_get_background_color(aStyle, aState, &gdkColor);
+  nscolor bgColor = GDK_RGBA_TO_NS_RGBA(gdkColor);
+  // background-image paints over background-color.
+  const nscolor finalColor = NS_ComposeColors(bgColor, imageColor);
+  if (finalColor != aOverBackgroundColor) {
+    return finalColor;
+  }
+  return NS_TRANSPARENT;
+}
+
+static nscolor GetTextColor(GtkStyleContext* aStyle,
+                            GtkStateFlags aState = GTK_STATE_FLAG_NORMAL) {
+  GdkRGBA color;
+  gtk_style_context_get_color(aStyle, aState, &color);
+  return GDK_RGBA_TO_NS_RGBA(color);
+}
+
+using ColorPair = nsLookAndFeel::ColorPair;
+static ColorPair GetColorPair(GtkStyleContext* aStyle,
+                              GtkStateFlags aState = GTK_STATE_FLAG_NORMAL) {
+  ColorPair result;
+  result.mFg = GetTextColor(aStyle, aState);
+  result.mBg = GetBackgroundColor(aStyle, result.mFg, aState);
+  return result;
+}
+
+static bool GetNamedColorPair(GtkStyleContext* aStyle, const char* aBgName,
+                              const char* aFgName, ColorPair* aPair) {
+  GdkRGBA bg, fg;
+  if (!gtk_style_context_lookup_color(aStyle, aBgName, &bg) ||
+      !gtk_style_context_lookup_color(aStyle, aFgName, &fg)) {
+    return false;
+  }
+
+  aPair->mBg = GDK_RGBA_TO_NS_RGBA(bg);
+  aPair->mFg = GDK_RGBA_TO_NS_RGBA(fg);
+
+  // If the colors are semi-transparent and the theme provides a
+  // background color, blend with them to get the "final" color, see
+  // bug 1717077.
+  if (NS_GET_A(aPair->mBg) != 255 &&
+      (gtk_style_context_lookup_color(aStyle, "bg_color", &bg) ||
+       gtk_style_context_lookup_color(aStyle, "theme_bg_color", &bg))) {
+    aPair->mBg = NS_ComposeColors(GDK_RGBA_TO_NS_RGBA(bg), aPair->mBg);
+  }
+
+  // A semi-transparent foreground color would be kinda silly, but is done
+  // for symmetry.
+  if (NS_GET_A(aPair->mFg) != 255) {
+    aPair->mFg = NS_ComposeColors(aPair->mBg, aPair->mFg);
+  }
+
+  return true;
+}
+
+static void EnsureColorPairIsOpaque(ColorPair& aPair) {
+  // Blend with white, ensuring the color is opaque, so that the UI doesn't have
+  // to care about alpha.
+  aPair.mBg = NS_ComposeColors(NS_RGB(0xff, 0xff, 0xff), aPair.mBg);
+  aPair.mFg = NS_ComposeColors(aPair.mBg, aPair.mFg);
+}
+
+static void PreferDarkerBackground(ColorPair& aPair) {
+  // We use the darker one unless the foreground isn't really a color (is all
+  // white / black / gray) and the background is, in which case we stick to what
+  // we have.
+  if (RelativeLuminanceUtils::Compute(aPair.mBg) >
+          RelativeLuminanceUtils::Compute(aPair.mFg) &&
+      (AnyColorChannelIsDifferent(aPair.mFg) ||
+       !AnyColorChannelIsDifferent(aPair.mBg))) {
+    std::swap(aPair.mBg, aPair.mFg);
+  }
+}
+
+void nsLookAndFeel::PerThemeData::Init() {
+  mName = GetGtkTheme();
+
+  mFamily = [&] {
+    if (mName.EqualsLiteral("Adwaita") || mName.EqualsLiteral("Adwaita-dark")) {
+      return ThemeFamily::Adwaita;
+    }
+    if (mName.EqualsLiteral("Breeze") || mName.EqualsLiteral("Breeze-Dark")) {
+      return ThemeFamily::Breeze;
+    }
+    if (StringBeginsWith(mName, "Yaru"_ns)) {
+      return ThemeFamily::Yaru;
+    }
+    return ThemeFamily::Unknown;
+  }();
+
+  GtkStyleContext* style;
+
+  mHighContrast = StaticPrefs::widget_content_gtk_high_contrast_enabled() &&
+                  mName.Find("HighContrast"_ns) >= 0;
+
+  mPreferDarkTheme = GetPreferDarkTheme();
+
+  mIsDark = GetThemeIsDark();
+
+  GdkRGBA color;
+  // Some themes style the <trough>, while others style the <scrollbar>
+  // itself, so we look at both and compose the colors.
+  style = GetStyleContext(MOZ_GTK_SCROLLBAR_VERTICAL);
+  gtk_style_context_get_background_color(style, GTK_STATE_FLAG_NORMAL, &color);
+  mThemedScrollbar = GDK_RGBA_TO_NS_RGBA(color);
+  gtk_style_context_get_background_color(style, GTK_STATE_FLAG_BACKDROP,
+                                         &color);
+  mThemedScrollbarInactive = GDK_RGBA_TO_NS_RGBA(color);
+
+  style = GetStyleContext(MOZ_GTK_SCROLLBAR_TROUGH_VERTICAL);
+  gtk_style_context_get_background_color(style, GTK_STATE_FLAG_NORMAL, &color);
+  mThemedScrollbar =
+      NS_ComposeColors(mThemedScrollbar, GDK_RGBA_TO_NS_RGBA(color));
+  gtk_style_context_get_background_color(style, GTK_STATE_FLAG_BACKDROP,
+                                         &color);
+  mThemedScrollbarInactive =
+      NS_ComposeColors(mThemedScrollbarInactive, GDK_RGBA_TO_NS_RGBA(color));
+
+  style = GetStyleContext(MOZ_GTK_SCROLLBAR_THUMB_VERTICAL);
+  gtk_style_context_get_background_color(style, GTK_STATE_FLAG_NORMAL, &color);
+  mThemedScrollbarThumb = GDK_RGBA_TO_NS_RGBA(color);
+  gtk_style_context_get_background_color(style, GTK_STATE_FLAG_PRELIGHT,
+                                         &color);
+  mThemedScrollbarThumbHover = GDK_RGBA_TO_NS_RGBA(color);
+  gtk_style_context_get_background_color(
+      style, GtkStateFlags(GTK_STATE_FLAG_PRELIGHT | GTK_STATE_FLAG_ACTIVE),
+      &color);
+  mThemedScrollbarThumbActive = GDK_RGBA_TO_NS_RGBA(color);
+  gtk_style_context_get_background_color(style, GTK_STATE_FLAG_BACKDROP,
+                                         &color);
+  mThemedScrollbarThumbInactive = GDK_RGBA_TO_NS_RGBA(color);
+
+  // Make sure that the thumb is visible, at least.
+  const bool fallbackToUnthemedColors = [&] {
+    if (!StaticPrefs::widget_gtk_theme_scrollbar_colors_enabled()) {
+      return true;
+    }
+
+    if (!ShouldHonorThemeScrollbarColors()) {
+      return true;
+    }
+    // If any of the scrollbar thumb colors are fully transparent, fall back to
+    // non-native ones.
+    if (!NS_GET_A(mThemedScrollbarThumb) ||
+        !NS_GET_A(mThemedScrollbarThumbHover) ||
+        !NS_GET_A(mThemedScrollbarThumbActive)) {
+      return true;
+    }
+    // If the thumb and track are the same color and opaque, fall back to
+    // non-native colors as well.
+    if (mThemedScrollbar == mThemedScrollbarThumb &&
+        NS_GET_A(mThemedScrollbar) == 0xff) {
+      return true;
+    }
+    return false;
+  }();
+
+  if (fallbackToUnthemedColors) {
+    if (mIsDark) {
+      // Taken from Adwaita-dark.
+      mThemedScrollbar = NS_RGB(0x31, 0x31, 0x31);
+      mThemedScrollbarInactive = NS_RGB(0x2d, 0x2d, 0x2d);
+      mThemedScrollbarThumb = NS_RGB(0xa3, 0xa4, 0xa4);
+      mThemedScrollbarThumbInactive = NS_RGB(0x59, 0x5a, 0x5a);
+    } else {
+      // Taken from Adwaita.
+      mThemedScrollbar = NS_RGB(0xce, 0xce, 0xce);
+      mThemedScrollbarInactive = NS_RGB(0xec, 0xed, 0xef);
+      mThemedScrollbarThumb = NS_RGB(0x82, 0x81, 0x7e);
+      mThemedScrollbarThumbInactive = NS_RGB(0xce, 0xcf, 0xce);
+    }
+
+    mThemedScrollbarThumbHover = ThemeColors::AdjustUnthemedScrollbarThumbColor(
+        mThemedScrollbarThumb, dom::ElementState::HOVER);
+    mThemedScrollbarThumbActive =
+        ThemeColors::AdjustUnthemedScrollbarThumbColor(
+            mThemedScrollbarThumb, dom::ElementState::ACTIVE);
+  }
+
+  // The label is not added to a parent widget, but shared for constructing
+  // different style contexts.  The node hierarchy is constructed only on
+  // the label style context.
+  GtkWidget* labelWidget = gtk_label_new("M");
+  g_object_ref_sink(labelWidget);
+
+  // Window colors
+  style = GetStyleContext(MOZ_GTK_WINDOW);
+  mWindow = mDialog = GetColorPair(style);
+
+  gtk_style_context_get_border_color(style, GTK_STATE_FLAG_NORMAL, &color);
+  mMozWindowActiveBorder = GDK_RGBA_TO_NS_RGBA(color);
+
+  gtk_style_context_get_border_color(style, GTK_STATE_FLAG_INSENSITIVE, &color);
+  mMozWindowInactiveBorder = GDK_RGBA_TO_NS_RGBA(color);
+
+  style = GetStyleContext(MOZ_GTK_WINDOW_CONTAINER);
+  {
+    GtkStyleContext* labelStyle = CreateStyleForWidget(labelWidget, style);
+    GetSystemFontInfo(labelStyle, &mDefaultFontName, &mDefaultFontStyle);
+    g_object_unref(labelStyle);
+  }
+
+  // tooltip foreground and background
+  style = GetStyleContext(MOZ_GTK_TOOLTIP_BOX_LABEL);
+  mInfo.mFg = GetTextColor(style);
+  style = GetStyleContext(MOZ_GTK_TOOLTIP);
+  mInfo.mBg = GetBackgroundColor(style, mInfo.mFg);
+
+  style = GetStyleContext(MOZ_GTK_MENUITEM);
+  {
+    GtkStyleContext* accelStyle =
+        CreateStyleForWidget(gtk_accel_label_new("M"), style);
+
+    GetSystemFontInfo(accelStyle, &mMenuFontName, &mMenuFontStyle);
+
+    gtk_style_context_get_color(accelStyle, GTK_STATE_FLAG_NORMAL, &color);
+    mMenu.mFg = GetTextColor(accelStyle);
+    mGrayText = GetTextColor(accelStyle, GTK_STATE_FLAG_INSENSITIVE);
+    g_object_unref(accelStyle);
+  }
+
+  const auto effectiveTitlebarStyle =
+      HeaderBarShouldDrawContainer(MOZ_GTK_HEADER_BAR) ? MOZ_GTK_HEADERBAR_FIXED
+                                                       : MOZ_GTK_HEADER_BAR;
+  style = GetStyleContext(effectiveTitlebarStyle);
+  {
+    mTitlebar = GetColorPair(style, GTK_STATE_FLAG_NORMAL);
+    mTitlebarInactive = GetColorPair(style, GTK_STATE_FLAG_BACKDROP);
+    mTitlebarRadius = IsSolidCSDStyleUsed() ? 0 : GetBorderRadius(style);
+  }
+
+  // We special-case the header bar color in Adwaita, Yaru and Breeze to be the
+  // titlebar color, because it looks better and matches what apps do by
+  // default, see bug 1838460.
+  //
+  // We only do this in the relevant desktop environments, however, since in
+  // other cases we don't really know if the DE's titlebars are going to match.
+  //
+  // For breeze, additionally we read the KDE colors directly, if available,
+  // since these are user-configurable.
+  //
+  // For most other themes or those in unknown DEs, we use the menubar colors.
+  //
+  // FIXME(emilio): Can we do something a bit less special-case-y?
+  const bool shouldUseTitlebarColorsForHeaderBar = [&] {
+    if (mFamily == ThemeFamily::Adwaita || mFamily == ThemeFamily::Yaru) {
+      return IsGnomeDesktopEnvironment();
+    }
+    if (mFamily == ThemeFamily::Breeze) {
+      return IsKdeDesktopEnvironment();
+    }
+    return false;
+  }();
+
+  if (shouldUseTitlebarColorsForHeaderBar) {
+    mHeaderBar = mTitlebar;
+    mHeaderBarInactive = mTitlebarInactive;
+    if (mFamily == ThemeFamily::Breeze) {
+      GetNamedColorPair(style, "theme_header_background_breeze",
+                        "theme_header_foreground_breeze", &mHeaderBar);
+      GetNamedColorPair(style, "theme_header_background_backdrop_breeze",
+                        "theme_header_foreground_backdrop_breeze",
+                        &mHeaderBarInactive);
+    }
+  } else {
+    style = GetStyleContext(MOZ_GTK_MENUBARITEM);
+    mHeaderBar.mFg = GetTextColor(style);
+    mHeaderBarInactive.mFg = GetTextColor(style, GTK_STATE_FLAG_BACKDROP);
+
+    style = GetStyleContext(MOZ_GTK_MENUBAR);
+    mHeaderBar.mBg = GetBackgroundColor(style, mHeaderBar.mFg);
+    mHeaderBarInactive.mBg = GetBackgroundColor(style, mHeaderBarInactive.mFg,
+                                                GTK_STATE_FLAG_BACKDROP);
+  }
+
+  style = GetStyleContext(MOZ_GTK_MENUPOPUP);
+  mMenu.mBg = [&] {
+    nscolor color = GetBackgroundColor(style, mMenu.mFg);
+    if (NS_GET_A(color)) {
+      return color;
+    }
+    // Some themes only style menupopups with the backdrop pseudo-class. Since a
+    // context / popup menu always seems to match that, try that before giving
+    // up.
+    color = GetBackgroundColor(style, mMenu.mFg, GTK_STATE_FLAG_BACKDROP);
+    if (NS_GET_A(color)) {
+      return color;
+    }
+    // If we get here we couldn't figure out the right color to use. Rather than
+    // falling back to transparent, fall back to the window background.
+    NS_WARNING(
+        "Couldn't find menu background color, falling back to window "
+        "background");
+    return mWindow.mBg;
+  }();
+
+  style = GetStyleContext(MOZ_GTK_MENUITEM);
+  gtk_style_context_get_color(style, GTK_STATE_FLAG_PRELIGHT, &color);
+  mMenuHover.mFg = GDK_RGBA_TO_NS_RGBA(color);
+  mMenuHover.mBg = NS_ComposeColors(
+      mMenu.mBg,
+      GetBackgroundColor(style, mMenu.mFg, GTK_STATE_FLAG_PRELIGHT, mMenu.mBg));
+
+  GtkWidget* parent = gtk_fixed_new();
+  GtkWidget* window = gtk_window_new(GTK_WINDOW_POPUP);
+  GtkWidget* treeView = gtk_tree_view_new();
+  GtkWidget* linkButton = gtk_link_button_new("http://example.com/");
+  GtkWidget* menuBar = gtk_menu_bar_new();
+  GtkWidget* menuBarItem = gtk_menu_item_new();
+  GtkWidget* entry = gtk_entry_new();
+  GtkWidget* textView = gtk_text_view_new();
+
+  gtk_container_add(GTK_CONTAINER(parent), treeView);
+  gtk_container_add(GTK_CONTAINER(parent), linkButton);
+  gtk_container_add(GTK_CONTAINER(parent), menuBar);
+  gtk_menu_shell_append(GTK_MENU_SHELL(menuBar), menuBarItem);
+  gtk_container_add(GTK_CONTAINER(window), parent);
+  gtk_container_add(GTK_CONTAINER(parent), entry);
+  gtk_container_add(GTK_CONTAINER(parent), textView);
+
+  // Text colors
+  GdkRGBA bgColor;
+  // If the text window background is translucent, then the background of
+  // the textview root node is visible.
+  style = GetStyleContext(MOZ_GTK_TEXT_VIEW);
+  gtk_style_context_get_background_color(style, GTK_STATE_FLAG_NORMAL,
+                                         &bgColor);
+
+  style = GetStyleContext(MOZ_GTK_TEXT_VIEW_TEXT);
+  gtk_style_context_get_background_color(style, GTK_STATE_FLAG_NORMAL, &color);
+  ApplyColorOver(color, &bgColor);
+  mField.mBg = GDK_RGBA_TO_NS_RGBA(bgColor);
+  gtk_style_context_get_color(style, GTK_STATE_FLAG_NORMAL, &color);
+  mField.mFg = GDK_RGBA_TO_NS_RGBA(color);
+  mSidebar = mField;
+
+  // Selected text and background
+  {
+    GtkStyleContext* selectionStyle =
+        GetStyleContext(MOZ_GTK_TEXT_VIEW_TEXT_SELECTION);
+    auto GrabSelectionColors = [&](GtkStyleContext* style) {
+      gtk_style_context_get_background_color(
+          style,
+          static_cast<GtkStateFlags>(GTK_STATE_FLAG_FOCUSED |
+                                     GTK_STATE_FLAG_SELECTED),
+          &color);
+      mSelectedText.mBg = GDK_RGBA_TO_NS_RGBA(color);
+      gtk_style_context_get_color(
+          style,
+          static_cast<GtkStateFlags>(GTK_STATE_FLAG_FOCUSED |
+                                     GTK_STATE_FLAG_SELECTED),
+          &color);
+      mSelectedText.mFg = GDK_RGBA_TO_NS_RGBA(color);
+    };
+    GrabSelectionColors(selectionStyle);
+    if (mSelectedText.mBg == mSelectedText.mFg) {
+      // Some old distros/themes don't properly use the .selection style, so
+      // fall back to the regular text view style.
+      GrabSelectionColors(style);
+    }
+
+    // Default selected item color is the selection background / foreground
+    // colors, but we prefer named colors, as those are more general purpose
+    // than the actual selection style, which might e.g. be too-transparent.
+    //
+    // NOTE(emilio): It's unclear which one of the theme_selected_* or the
+    // selected_* pairs should we prefer, in all themes that define both that
+    // I've found, they're always the same.
+    if (!GetNamedColorPair(style, "selected_bg_color", "selected_fg_color",
+                           &mSelectedItem) &&
+        !GetNamedColorPair(style, "theme_selected_bg_color",
+                           "theme_selected_fg_color", &mSelectedItem)) {
+      mSelectedItem = mSelectedText;
+    }
+
+    EnsureColorPairIsOpaque(mSelectedItem);
+
+    // In a similar fashion, default accent color is the selected item/text
+    // pair, but we also prefer named colors, if available.
+    //
+    // accent_{bg,fg}_color is not _really_ a gtk3 thing (it's a gtk4 thing),
+    // but if gtk 3 themes want to specify these we let them, see:
+    //
+    //   https://gnome.pages.gitlab.gnome.org/libadwaita/doc/main/named-colors.html#accent-colors
+    if (!GetNamedColorPair(style, "accent_bg_color", "accent_fg_color",
+                           &mAccent)) {
+      mAccent = mSelectedItem;
+    }
+
+    EnsureColorPairIsOpaque(mAccent);
+    PreferDarkerBackground(mAccent);
+  }
+
+  // Button text color
+  style = GetStyleContext(MOZ_GTK_BUTTON);
+  {
+    GtkStyleContext* labelStyle = CreateStyleForWidget(labelWidget, style);
+    GetSystemFontInfo(labelStyle, &mButtonFontName, &mButtonFontStyle);
+    g_object_unref(labelStyle);
+  }
+
+  gtk_style_context_get_border_color(style, GTK_STATE_FLAG_NORMAL, &color);
+  mButtonBorder = GDK_RGBA_TO_NS_RGBA(color);
+  mButton = GetColorPair(style);
+  mButtonHover = GetColorPair(style, GTK_STATE_FLAG_PRELIGHT);
+  mButtonActive = GetColorPair(style, GTK_STATE_FLAG_ACTIVE);
+  if (!NS_GET_A(mButtonHover.mBg)) {
+    mButtonHover.mBg = mWindow.mBg;
+  }
+  if (!NS_GET_A(mButtonActive.mBg)) {
+    mButtonActive.mBg = mWindow.mBg;
+  }
+
+  // Combobox text color
+  style = GetStyleContext(MOZ_GTK_COMBOBOX_ENTRY_TEXTAREA);
+  gtk_style_context_get_color(style, GTK_STATE_FLAG_NORMAL, &color);
+  mComboBoxText = GDK_RGBA_TO_NS_RGBA(color);
+
+  // GTK's guide to fancy odd row background colors:
+  // 1) Check if a theme explicitly defines an odd row color
+  // 2) If not, check if it defines an even row color, and darken it
+  //    slightly by a hardcoded value (gtkstyle.c)
+  // 3) If neither are defined, take the base background color and
+  //    darken that by a hardcoded value
+  style = GetStyleContext(MOZ_GTK_TREEVIEW);
+
+  // Get odd row background color
+  gtk_style_context_save(style);
+  gtk_style_context_add_region(style, GTK_STYLE_REGION_ROW, GTK_REGION_ODD);
+  gtk_style_context_get_background_color(style, GTK_STATE_FLAG_NORMAL, &color);
+  mOddCellBackground = GDK_RGBA_TO_NS_RGBA(color);
+  gtk_style_context_restore(style);
+
+  // Column header colors
+  style = GetStyleContext(MOZ_GTK_TREE_HEADER_CELL);
+  mMozColHeader = GetColorPair(style, GTK_STATE_FLAG_NORMAL);
+  mMozColHeaderHover = GetColorPair(style, GTK_STATE_FLAG_NORMAL);
+  mMozColHeaderActive = GetColorPair(style, GTK_STATE_FLAG_ACTIVE);
+
+  // Compute cell highlight colors
+  InitCellHighlightColors();
+
+  // GtkFrame has a "border" subnode on which Adwaita draws the border.
+  // Some themes do not draw on this node but draw a border on the widget
+  // root node, so check the root node if no border is found on the border
+  // node.
+  style = GetStyleContext(MOZ_GTK_FRAME_BORDER);
+  bool themeUsesColors =
+      GetBorderColors(style, &mThreeDHighlight, &mThreeDShadow);
+  if (!themeUsesColors) {
+    style = GetStyleContext(MOZ_GTK_FRAME);
+    GetBorderColors(style, &mThreeDHighlight, &mThreeDShadow);
+  }
+  mSidebarBorder = mThreeDShadow;
+
+  // Some themes have a unified menu bar, and support window dragging on it
+  gboolean supports_menubar_drag = FALSE;
+  GParamSpec* param_spec = gtk_widget_class_find_style_property(
+      GTK_WIDGET_GET_CLASS(menuBar), "window-dragging");
+  if (param_spec) {
+    if (g_type_is_a(G_PARAM_SPEC_VALUE_TYPE(param_spec), G_TYPE_BOOLEAN)) {
+      gtk_widget_style_get(menuBar, "window-dragging", &supports_menubar_drag,
+                           nullptr);
+    }
+  }
+  mMenuSupportsDrag = supports_menubar_drag;
+
+  // TODO: It returns wrong color for themes which
+  // sets link color for GtkLabel only as we query
+  // GtkLinkButton style here.
+  style = gtk_widget_get_style_context(linkButton);
+  gtk_style_context_get_color(style, GTK_STATE_FLAG_LINK, &color);
+  mNativeHyperLinkText = GDK_RGBA_TO_NS_RGBA(color);
+
+  gtk_style_context_get_color(style, GTK_STATE_FLAG_VISITED, &color);
+  mNativeVisitedHyperLinkText = GDK_RGBA_TO_NS_RGBA(color);
+
+  // invisible character styles
+  guint value;
+  g_object_get(entry, "invisible-char", &value, nullptr);
+  mInvisibleCharacter = char16_t(value);
+
+  // caret styles
+  gtk_widget_style_get(entry, "cursor-aspect-ratio", &mCaretRatio, nullptr);
+
+  GetSystemFontInfo(gtk_widget_get_style_context(entry), &mFieldFontName,
+                    &mFieldFontStyle);
+
+  gtk_widget_destroy(window);
+  g_object_unref(labelWidget);
+
+  if (LOGLNF_ENABLED()) {
+    LOGLNF("Initialized theme %s (%d)\n", mName.get(), mPreferDarkTheme);
+    for (auto id : MakeEnumeratedRange(ColorID::End)) {
+      nscolor color;
+      nsresult rv = GetColor(id, color);
+      LOGLNF(" * color %d: pref=%s success=%d value=%x\n", int(id),
+             GetColorPrefName(id), NS_SUCCEEDED(rv),
+             NS_SUCCEEDED(rv) ? color : 0);
+    }
+    LOGLNF(" * titlebar-radius: %d\n", mTitlebarRadius);
+  }
+}
+
+// virtual
+char16_t nsLookAndFeel::GetPasswordCharacterImpl() {
+  EnsureInit();
+  return mSystemTheme.mInvisibleCharacter;
+}
+
+bool nsLookAndFeel::GetEchoPasswordImpl() { return false; }
+
+bool nsLookAndFeel::GetDefaultDrawInTitlebar() { return sCSDAvailable; }
+
+nsXPLookAndFeel::TitlebarAction nsLookAndFeel::GetTitlebarAction(
+    TitlebarEvent aEvent) {
+  return aEvent == TitlebarEvent::Double_Click ? mDoubleClickAction
+                                               : mMiddleClickAction;
+}
+
+void nsLookAndFeel::GetThemeInfo(nsACString& aInfo) {
+  aInfo.Append(mSystemTheme.mName);
+  aInfo.Append(" / ");
+  aInfo.Append(mAltTheme.mName);
+}
+
+bool nsLookAndFeel::WidgetUsesImage(WidgetNodeType aNodeType) {
+  static constexpr GtkStateFlags sFlagsToCheck[]{
+      GTK_STATE_FLAG_NORMAL, GTK_STATE_FLAG_PRELIGHT,
+      GtkStateFlags(GTK_STATE_FLAG_PRELIGHT | GTK_STATE_FLAG_ACTIVE),
+      GTK_STATE_FLAG_BACKDROP, GTK_STATE_FLAG_INSENSITIVE};
+
+  GtkStyleContext* style = GetStyleContext(aNodeType);
+
+  GValue value = G_VALUE_INIT;
+  for (GtkStateFlags state : sFlagsToCheck) {
+    gtk_style_context_get_property(style, "background-image", state, &value);
+    bool hasPattern = G_VALUE_TYPE(&value) == CAIRO_GOBJECT_TYPE_PATTERN &&
+                      g_value_get_boxed(&value);
+    g_value_unset(&value);
+    if (hasPattern) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void nsLookAndFeel::RecordLookAndFeelSpecificTelemetry() {
+  // Gtk version we're on.
+  nsString version;
+  version.AppendPrintf("%d.%d", gtk_major_version, gtk_minor_version);
+  Telemetry::ScalarSet(Telemetry::ScalarID::WIDGET_GTK_VERSION, version);
+
+  // Whether the current Gtk theme has scrollbar buttons.
+  bool hasScrollbarButtons =
+      GetInt(LookAndFeel::IntID::ScrollArrowStyle) != eScrollArrow_None;
+  mozilla::Telemetry::ScalarSet(
+      mozilla::Telemetry::ScalarID::WIDGET_GTK_THEME_HAS_SCROLLBAR_BUTTONS,
+      hasScrollbarButtons);
+
+  // Whether the current Gtk theme uses something other than a solid color
+  // background for scrollbar parts.
+  bool scrollbarUsesImage = !ShouldHonorThemeScrollbarColors();
+  mozilla::Telemetry::ScalarSet(
+      mozilla::Telemetry::ScalarID::WIDGET_GTK_THEME_SCROLLBAR_USES_IMAGES,
+      scrollbarUsesImage);
+}
+
+bool nsLookAndFeel::ShouldHonorThemeScrollbarColors() {
+  // If the Gtk theme uses anything other than solid color backgrounds for Gtk
+  // scrollbar parts, this is a good indication that painting XUL scrollbar part
+  // elements using colors extracted from the theme won't provide good results.
+  return !WidgetUsesImage(MOZ_GTK_SCROLLBAR_VERTICAL) &&
+         !WidgetUsesImage(MOZ_GTK_SCROLLBAR_CONTENTS_VERTICAL) &&
+         !WidgetUsesImage(MOZ_GTK_SCROLLBAR_TROUGH_VERTICAL) &&
+         !WidgetUsesImage(MOZ_GTK_SCROLLBAR_THUMB_VERTICAL);
+}
+
+#undef LOGLNF
+#undef LOGLNF_ENABLED
diff --git a/widget/gtk/nsLookAndFeel.h b/widget/gtk/nsLookAndFeel.h
new file mode 100644
index 0000000000..56608d331f
--- /dev/null
+++ b/widget/gtk/nsLookAndFeel.h
@@ -0,0 +1,211 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsLookAndFeel
+#define __nsLookAndFeel
+
+#include "X11UndefineNone.h"
+#include "nsXPLookAndFeel.h"
+#include "nsCOMPtr.h"
+#include "gfxFont.h"
+
+enum WidgetNodeType : int;
+struct _GtkStyle;
+typedef struct _GDBusProxy GDBusProxy;
+typedef struct _GtkCssProvider GtkCssProvider;
+typedef struct _GFile GFile;
+typedef struct _GFileMonitor GFileMonitor;
+
+namespace mozilla {
+enum class StyleGtkThemeFamily : uint8_t;
+}
+
+class nsLookAndFeel final : public nsXPLookAndFeel {
+ public:
+  nsLookAndFeel();
+  virtual ~nsLookAndFeel();
+
+  void NativeInit() final;
+  void RefreshImpl() override;
+  nsresult NativeGetInt(IntID aID, int32_t& aResult) override;
+  nsresult NativeGetFloat(FloatID aID, float& aResult) override;
+  nsresult NativeGetColor(ColorID, ColorScheme, nscolor& aResult) override;
+  bool NativeGetFont(FontID aID, nsString& aFontName,
+                     gfxFontStyle& aFontStyle) override;
+
+  char16_t GetPasswordCharacterImpl() override;
+  bool GetEchoPasswordImpl() override;
+
+  bool GetDefaultDrawInTitlebar() override;
+
+  nsXPLookAndFeel::TitlebarAction GetTitlebarAction(
+      TitlebarEvent aEvent) override;
+
+  void GetThemeInfo(nsACString&) override;
+
+  static const nscolor kBlack = NS_RGB(0, 0, 0);
+  static const nscolor kWhite = NS_RGB(255, 255, 255);
+  void OnColorSchemeSettingChanged();
+
+  struct ColorPair {
+    nscolor mBg = kWhite;
+    nscolor mFg = kBlack;
+  };
+
+  using ThemeFamily = mozilla::StyleGtkThemeFamily;
+
+ protected:
+  static bool WidgetUsesImage(WidgetNodeType aNodeType);
+  void RecordLookAndFeelSpecificTelemetry() override;
+  static bool ShouldHonorThemeScrollbarColors();
+  mozilla::Maybe<ColorScheme> ComputeColorSchemeSetting();
+
+  void WatchDBus();
+  void UnwatchDBus();
+
+  // We use up to two themes (one light, one dark), which might have different
+  // sets of fonts and colors.
+  struct PerThemeData {
+    nsCString mName;
+    bool mIsDark = false;
+    bool mHighContrast = false;
+    bool mPreferDarkTheme = false;
+
+    ThemeFamily mFamily{0};
+
+    // Cached fonts
+    nsString mDefaultFontName;
+    nsString mButtonFontName;
+    nsString mFieldFontName;
+    nsString mMenuFontName;
+    gfxFontStyle mDefaultFontStyle;
+    gfxFontStyle mButtonFontStyle;
+    gfxFontStyle mFieldFontStyle;
+    gfxFontStyle mMenuFontStyle;
+
+    // Cached colors
+    nscolor mGrayText = kBlack;
+    ColorPair mInfo;
+    ColorPair mMenu;
+    ColorPair mMenuHover;
+    ColorPair mHeaderBar;
+    ColorPair mHeaderBarInactive;
+    ColorPair mButton;
+    ColorPair mButtonHover;
+    ColorPair mButtonActive;
+    nscolor mButtonBorder = kBlack;
+    nscolor mThreeDHighlight = kBlack;
+    nscolor mThreeDShadow = kBlack;
+    nscolor mOddCellBackground = kWhite;
+    nscolor mNativeHyperLinkText = kBlack;
+    nscolor mNativeVisitedHyperLinkText = kBlack;
+    // FIXME: This doesn't seem like it'd be sound since we use Window for
+    // -moz-Combobox... But I guess we rely on chrome code not setting
+    // appearance: none on selects or overriding the color if they do.
+    nscolor mComboBoxText = kBlack;
+    ColorPair mField;
+    ColorPair mWindow;
+    ColorPair mDialog;
+    ColorPair mSidebar;
+    nscolor mSidebarBorder = kBlack;
+
+    nscolor mMozWindowActiveBorder = kBlack;
+    nscolor mMozWindowInactiveBorder = kBlack;
+
+    ColorPair mCellHighlight;
+    ColorPair mSelectedText;
+    ColorPair mAccent;
+    ColorPair mSelectedItem;
+
+    ColorPair mMozColHeader;
+    ColorPair mMozColHeaderHover;
+    ColorPair mMozColHeaderActive;
+
+    ColorPair mTitlebar;
+    ColorPair mTitlebarInactive;
+
+    nscolor mThemedScrollbar = kWhite;
+    nscolor mThemedScrollbarInactive = kWhite;
+    nscolor mThemedScrollbarThumb = kBlack;
+    nscolor mThemedScrollbarThumbHover = kBlack;
+    nscolor mThemedScrollbarThumbActive = kBlack;
+    nscolor mThemedScrollbarThumbInactive = kBlack;
+
+    float mCaretRatio = 0.0f;
+    int32_t mTitlebarRadius = 0;
+    char16_t mInvisibleCharacter = 0;
+    bool mMenuSupportsDrag = false;
+
+    void Init();
+    nsresult GetColor(ColorID, nscolor&) const;
+    bool GetFont(FontID, nsString& aFontName, gfxFontStyle&) const;
+    void InitCellHighlightColors();
+  };
+
+  PerThemeData mSystemTheme;
+
+  // If the system theme is light, a dark theme. Otherwise, a light theme. The
+  // alternative theme to the current one is preferred, but otherwise we fall
+  // back to Adwaita / Adwaita Dark, respectively.
+  PerThemeData mAltTheme;
+
+  const PerThemeData& LightTheme() const {
+    return mSystemTheme.mIsDark ? mAltTheme : mSystemTheme;
+  }
+
+  const PerThemeData& DarkTheme() const {
+    return mSystemTheme.mIsDark ? mSystemTheme : mAltTheme;
+  }
+
+  const PerThemeData& EffectiveTheme() const {
+    return mSystemThemeOverridden ? mAltTheme : mSystemTheme;
+  }
+
+  uint32_t mDBusID = 0;
+  RefPtr<GDBusProxy> mDBusSettingsProxy;
+  RefPtr<GFile> mKdeColors;
+  RefPtr<GFileMonitor> mKdeColorsMonitor;
+  mozilla::Maybe<ColorScheme> mColorSchemePreference;
+  int32_t mCaretBlinkTime = 0;
+  int32_t mCaretBlinkCount = -1;
+  bool mCSDMaximizeButton = false;
+  bool mCSDMinimizeButton = false;
+  bool mCSDCloseButton = false;
+  bool mCSDReversedPlacement = false;
+  bool mPrefersReducedMotion = false;
+  bool mInitialized = false;
+  bool mSystemThemeOverridden = false;
+  int32_t mCSDMaximizeButtonPosition = 0;
+  int32_t mCSDMinimizeButtonPosition = 0;
+  int32_t mCSDCloseButtonPosition = 0;
+  TitlebarAction mDoubleClickAction = TitlebarAction::None;
+  TitlebarAction mMiddleClickAction = TitlebarAction::None;
+
+  RefPtr<GtkCssProvider> mRoundedCornerProvider;
+  void UpdateRoundedBottomCornerStyles();
+
+  void ClearRoundedCornerProvider();
+
+  void EnsureInit() {
+    if (mInitialized) {
+      return;
+    }
+    Initialize();
+  }
+
+  void Initialize();
+
+  void RestoreSystemTheme();
+  void InitializeGlobalSettings();
+  // Returns whether we found an alternative theme.
+  bool ConfigureAltTheme();
+  void ConfigureAndInitializeAltTheme();
+  void ConfigureFinalEffectiveTheme();
+  void MaybeApplyAdwaitaOverrides();
+};
+
+#endif
diff --git a/widget/gtk/nsNativeThemeGTK.cpp b/widget/gtk/nsNativeThemeGTK.cpp
new file mode 100644
index 0000000000..06d9b48007
--- /dev/null
+++ b/widget/gtk/nsNativeThemeGTK.cpp
@@ -0,0 +1,1369 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsNativeThemeGTK.h"
+#include "nsPresContext.h"
+#include "nsStyleConsts.h"
+#include "gtkdrawing.h"
+#include "ScreenHelperGTK.h"
+#include "WidgetUtilsGtk.h"
+
+#include "gfx2DGlue.h"
+#include "nsIObserverService.h"
+#include "nsIFrame.h"
+#include "nsIContent.h"
+#include "nsViewManager.h"
+#include "nsNameSpaceManager.h"
+#include "nsGfxCIID.h"
+#include "nsTransform2D.h"
+#include "nsXULPopupManager.h"
+#include "tree/nsTreeBodyFrame.h"
+#include "prlink.h"
+#include "nsGkAtoms.h"
+#include "nsAttrValueInlines.h"
+
+#include "mozilla/dom/HTMLInputElement.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Services.h"
+
+#include <gdk/gdkprivate.h>
+#include <gtk/gtk.h>
+
+#include "gfxContext.h"
+#include "mozilla/dom/XULButtonElement.h"
+#include "mozilla/gfx/BorrowedContext.h"
+#include "mozilla/gfx/HelpersCairo.h"
+#include "mozilla/gfx/PathHelpers.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/layers/StackingContextHelper.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsWindow.h"
+#include "nsLayoutUtils.h"
+#include "Theme.h"
+
+#ifdef MOZ_X11
+#  ifdef CAIRO_HAS_XLIB_SURFACE
+#    include "cairo-xlib.h"
+#  endif
+#endif
+
+#include <algorithm>
+#include <dlfcn.h>
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using namespace mozilla::widget;
+
+static int gLastGdkError;
+
+// Return widget scale factor of the monitor where the window is located by the
+// most part. We intentionally honor the text scale factor here in order to
+// have consistent scaling with other UI elements.
+static inline CSSToLayoutDeviceScale GetWidgetScaleFactor(nsIFrame* aFrame) {
+  return aFrame->PresContext()->CSSToDevPixelScale();
+}
+
+nsNativeThemeGTK::nsNativeThemeGTK() : Theme(ScrollbarStyle()) {
+  if (moz_gtk_init() != MOZ_GTK_SUCCESS) {
+    memset(mDisabledWidgetTypes, 0xff, sizeof(mDisabledWidgetTypes));
+    return;
+  }
+
+  ThemeChanged();
+}
+
+nsNativeThemeGTK::~nsNativeThemeGTK() { moz_gtk_shutdown(); }
+
+void nsNativeThemeGTK::RefreshWidgetWindow(nsIFrame* aFrame) {
+  MOZ_ASSERT(aFrame);
+  MOZ_ASSERT(aFrame->PresShell());
+
+  nsViewManager* vm = aFrame->PresShell()->GetViewManager();
+  if (!vm) {
+    return;
+  }
+  vm->InvalidateAllViews();
+}
+
+static bool IsFrameContentNodeInNamespace(nsIFrame* aFrame,
+                                          uint32_t aNamespace) {
+  nsIContent* content = aFrame ? aFrame->GetContent() : nullptr;
+  if (!content) return false;
+  return content->IsInNamespace(aNamespace);
+}
+
+static bool IsWidgetTypeDisabled(const uint8_t* aDisabledVector,
+                                 StyleAppearance aAppearance) {
+  auto type = static_cast<size_t>(aAppearance);
+  MOZ_ASSERT(type < static_cast<size_t>(StyleAppearance::Count));
+  return (aDisabledVector[type >> 3] & (1 << (type & 7))) != 0;
+}
+
+static void SetWidgetTypeDisabled(uint8_t* aDisabledVector,
+                                  StyleAppearance aAppearance) {
+  auto type = static_cast<size_t>(aAppearance);
+  MOZ_ASSERT(type < static_cast<size_t>(mozilla::StyleAppearance::Count));
+  aDisabledVector[type >> 3] |= (1 << (type & 7));
+}
+
+static inline uint16_t GetWidgetStateKey(StyleAppearance aAppearance,
+                                         GtkWidgetState* aWidgetState) {
+  return (aWidgetState->active | aWidgetState->focused << 1 |
+          aWidgetState->inHover << 2 | aWidgetState->disabled << 3 |
+          aWidgetState->isDefault << 4 |
+          static_cast<uint16_t>(aAppearance) << 5);
+}
+
+static bool IsWidgetStateSafe(uint8_t* aSafeVector, StyleAppearance aAppearance,
+                              GtkWidgetState* aWidgetState) {
+  MOZ_ASSERT(static_cast<size_t>(aAppearance) <
+             static_cast<size_t>(mozilla::StyleAppearance::Count));
+  uint16_t key = GetWidgetStateKey(aAppearance, aWidgetState);
+  return (aSafeVector[key >> 3] & (1 << (key & 7))) != 0;
+}
+
+static void SetWidgetStateSafe(uint8_t* aSafeVector,
+                               StyleAppearance aAppearance,
+                               GtkWidgetState* aWidgetState) {
+  MOZ_ASSERT(static_cast<size_t>(aAppearance) <
+             static_cast<size_t>(mozilla::StyleAppearance::Count));
+  uint16_t key = GetWidgetStateKey(aAppearance, aWidgetState);
+  aSafeVector[key >> 3] |= (1 << (key & 7));
+}
+
+/* static */
+GtkTextDirection nsNativeThemeGTK::GetTextDirection(nsIFrame* aFrame) {
+  // IsFrameRTL() treats vertical-rl modes as right-to-left (in addition to
+  // horizontal text with direction=RTL), rather than just considering the
+  // text direction.  GtkTextDirection does not have distinct values for
+  // vertical writing modes, but considering the block flow direction is
+  // important for resizers and scrollbar elements, at least.
+  return IsFrameRTL(aFrame) ? GTK_TEXT_DIR_RTL : GTK_TEXT_DIR_LTR;
+}
+
+// Returns positive for negative margins (otherwise 0).
+gint nsNativeThemeGTK::GetTabMarginPixels(nsIFrame* aFrame) {
+  nscoord margin = IsBottomTab(aFrame) ? aFrame->GetUsedMargin().top
+                                       : aFrame->GetUsedMargin().bottom;
+
+  return std::min<gint>(
+      MOZ_GTK_TAB_MARGIN_MASK,
+      std::max(0, aFrame->PresContext()->AppUnitsToDevPixels(-margin)));
+}
+
+bool nsNativeThemeGTK::GetGtkWidgetAndState(StyleAppearance aAppearance,
+                                            nsIFrame* aFrame,
+                                            WidgetNodeType& aGtkWidgetType,
+                                            GtkWidgetState* aState,
+                                            gint* aWidgetFlags) {
+  if (aWidgetFlags) {
+    *aWidgetFlags = 0;
+  }
+
+  ElementState elementState = GetContentState(aFrame, aAppearance);
+  if (aState) {
+    memset(aState, 0, sizeof(GtkWidgetState));
+
+    // For XUL checkboxes and radio buttons, the state of the parent
+    // determines our state.
+    if (aWidgetFlags) {
+      if (elementState.HasState(ElementState::CHECKED)) {
+        *aWidgetFlags |= MOZ_GTK_WIDGET_CHECKED;
+      }
+      if (elementState.HasState(ElementState::INDETERMINATE)) {
+        *aWidgetFlags |= MOZ_GTK_WIDGET_INCONSISTENT;
+      }
+    }
+
+    aState->disabled =
+        elementState.HasState(ElementState::DISABLED) || IsReadOnly(aFrame);
+    aState->active = elementState.HasState(ElementState::ACTIVE);
+    aState->focused = elementState.HasState(ElementState::FOCUS);
+    aState->inHover = elementState.HasState(ElementState::HOVER);
+    aState->isDefault = IsDefaultButton(aFrame);
+    aState->canDefault = FALSE;  // XXX fix me
+
+    if (aAppearance == StyleAppearance::Button ||
+        aAppearance == StyleAppearance::Toolbarbutton ||
+        aAppearance == StyleAppearance::Dualbutton ||
+        aAppearance == StyleAppearance::ToolbarbuttonDropdown ||
+        aAppearance == StyleAppearance::Menulist ||
+        aAppearance == StyleAppearance::MenulistButton) {
+      aState->active &= aState->inHover;
+    } else if (aAppearance == StyleAppearance::Treetwisty ||
+               aAppearance == StyleAppearance::Treetwistyopen) {
+      if (nsTreeBodyFrame* treeBodyFrame = do_QueryFrame(aFrame)) {
+        const mozilla::AtomArray& atoms =
+            treeBodyFrame->GetPropertyArrayForCurrentDrawingItem();
+        aState->selected = atoms.Contains(nsGkAtoms::selected);
+        aState->inHover = atoms.Contains(nsGkAtoms::hover);
+      }
+    }
+
+    if (IsFrameContentNodeInNamespace(aFrame, kNameSpaceID_XUL)) {
+      // For these widget types, some element (either a child or parent)
+      // actually has element focus, so we check the focused attribute
+      // to see whether to draw in the focused state.
+      aState->focused = elementState.HasState(ElementState::FOCUSRING);
+      if (aAppearance == StyleAppearance::Radio ||
+          aAppearance == StyleAppearance::Checkbox) {
+        // In XUL, checkboxes and radios shouldn't have focus rings, their
+        // labels do
+        aState->focused = FALSE;
+      }
+
+      // A button with drop down menu open or an activated toggle button
+      // should always appear depressed.
+      if (aAppearance == StyleAppearance::Button ||
+          aAppearance == StyleAppearance::Toolbarbutton ||
+          aAppearance == StyleAppearance::Dualbutton ||
+          aAppearance == StyleAppearance::ToolbarbuttonDropdown ||
+          aAppearance == StyleAppearance::Menulist ||
+          aAppearance == StyleAppearance::MenulistButton) {
+        bool menuOpen = IsOpenButton(aFrame);
+        aState->depressed = IsCheckedButton(aFrame) || menuOpen;
+        // we must not highlight buttons with open drop down menus on hover.
+        aState->inHover = aState->inHover && !menuOpen;
+      }
+    }
+
+    if (aAppearance == StyleAppearance::MozWindowTitlebar ||
+        aAppearance == StyleAppearance::MozWindowTitlebarMaximized ||
+        aAppearance == StyleAppearance::MozWindowButtonClose ||
+        aAppearance == StyleAppearance::MozWindowButtonMinimize ||
+        aAppearance == StyleAppearance::MozWindowButtonMaximize ||
+        aAppearance == StyleAppearance::MozWindowButtonRestore) {
+      aState->backdrop = !nsWindow::GetTopLevelWindowActiveState(aFrame);
+    }
+  }
+
+  switch (aAppearance) {
+    case StyleAppearance::Button:
+      if (aWidgetFlags) *aWidgetFlags = GTK_RELIEF_NORMAL;
+      aGtkWidgetType = MOZ_GTK_BUTTON;
+      break;
+    case StyleAppearance::Toolbarbutton:
+    case StyleAppearance::Dualbutton:
+      if (aWidgetFlags) *aWidgetFlags = GTK_RELIEF_NONE;
+      aGtkWidgetType = MOZ_GTK_TOOLBAR_BUTTON;
+      break;
+    case StyleAppearance::Checkbox:
+      aGtkWidgetType = MOZ_GTK_CHECKBUTTON;
+      break;
+    case StyleAppearance::Radio:
+      aGtkWidgetType = MOZ_GTK_RADIOBUTTON;
+      break;
+    case StyleAppearance::Spinner:
+      aGtkWidgetType = MOZ_GTK_SPINBUTTON;
+      break;
+    case StyleAppearance::SpinnerUpbutton:
+      aGtkWidgetType = MOZ_GTK_SPINBUTTON_UP;
+      break;
+    case StyleAppearance::SpinnerDownbutton:
+      aGtkWidgetType = MOZ_GTK_SPINBUTTON_DOWN;
+      break;
+    case StyleAppearance::SpinnerTextfield:
+      aGtkWidgetType = MOZ_GTK_SPINBUTTON_ENTRY;
+      break;
+    case StyleAppearance::Range: {
+      if (IsRangeHorizontal(aFrame)) {
+        if (aWidgetFlags) *aWidgetFlags = GTK_ORIENTATION_HORIZONTAL;
+        aGtkWidgetType = MOZ_GTK_SCALE_HORIZONTAL;
+      } else {
+        if (aWidgetFlags) *aWidgetFlags = GTK_ORIENTATION_VERTICAL;
+        aGtkWidgetType = MOZ_GTK_SCALE_VERTICAL;
+      }
+      break;
+    }
+    case StyleAppearance::RangeThumb: {
+      if (IsRangeHorizontal(aFrame)) {
+        if (aWidgetFlags) *aWidgetFlags = GTK_ORIENTATION_HORIZONTAL;
+        aGtkWidgetType = MOZ_GTK_SCALE_THUMB_HORIZONTAL;
+      } else {
+        if (aWidgetFlags) *aWidgetFlags = GTK_ORIENTATION_VERTICAL;
+        aGtkWidgetType = MOZ_GTK_SCALE_THUMB_VERTICAL;
+      }
+      break;
+    }
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+      aGtkWidgetType = MOZ_GTK_ENTRY;
+      break;
+    case StyleAppearance::Textarea:
+      aGtkWidgetType = MOZ_GTK_TEXT_VIEW;
+      break;
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Treeview:
+      aGtkWidgetType = MOZ_GTK_TREEVIEW;
+      break;
+    case StyleAppearance::Treetwisty:
+      aGtkWidgetType = MOZ_GTK_TREEVIEW_EXPANDER;
+      if (aWidgetFlags) *aWidgetFlags = GTK_EXPANDER_COLLAPSED;
+      break;
+    case StyleAppearance::Treetwistyopen:
+      aGtkWidgetType = MOZ_GTK_TREEVIEW_EXPANDER;
+      if (aWidgetFlags) *aWidgetFlags = GTK_EXPANDER_EXPANDED;
+      break;
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Menulist:
+      aGtkWidgetType = MOZ_GTK_DROPDOWN;
+      if (aWidgetFlags)
+        *aWidgetFlags =
+            IsFrameContentNodeInNamespace(aFrame, kNameSpaceID_XHTML);
+      break;
+    case StyleAppearance::ToolbarbuttonDropdown:
+    case StyleAppearance::ButtonArrowDown:
+    case StyleAppearance::ButtonArrowUp:
+    case StyleAppearance::ButtonArrowNext:
+    case StyleAppearance::ButtonArrowPrevious:
+      aGtkWidgetType = MOZ_GTK_TOOLBARBUTTON_ARROW;
+      if (aWidgetFlags) {
+        *aWidgetFlags = GTK_ARROW_DOWN;
+
+        if (aAppearance == StyleAppearance::ButtonArrowUp)
+          *aWidgetFlags = GTK_ARROW_UP;
+        else if (aAppearance == StyleAppearance::ButtonArrowNext)
+          *aWidgetFlags = GTK_ARROW_RIGHT;
+        else if (aAppearance == StyleAppearance::ButtonArrowPrevious)
+          *aWidgetFlags = GTK_ARROW_LEFT;
+      }
+      break;
+    case StyleAppearance::Tooltip:
+      aGtkWidgetType = MOZ_GTK_TOOLTIP;
+      break;
+    case StyleAppearance::ProgressBar:
+      aGtkWidgetType = MOZ_GTK_PROGRESSBAR;
+      break;
+    case StyleAppearance::Progresschunk: {
+      nsIFrame* stateFrame = aFrame->GetParent();
+      ElementState elementState = GetContentState(stateFrame, aAppearance);
+
+      aGtkWidgetType = elementState.HasState(ElementState::INDETERMINATE)
+                           ? IsVerticalProgress(stateFrame)
+                                 ? MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE
+                                 : MOZ_GTK_PROGRESS_CHUNK_INDETERMINATE
+                           : MOZ_GTK_PROGRESS_CHUNK;
+    } break;
+    case StyleAppearance::TabScrollArrowBack:
+    case StyleAppearance::TabScrollArrowForward:
+      if (aWidgetFlags)
+        *aWidgetFlags = aAppearance == StyleAppearance::TabScrollArrowBack
+                            ? GTK_ARROW_LEFT
+                            : GTK_ARROW_RIGHT;
+      aGtkWidgetType = MOZ_GTK_TAB_SCROLLARROW;
+      break;
+    case StyleAppearance::Tabpanels:
+      aGtkWidgetType = MOZ_GTK_TABPANELS;
+      break;
+    case StyleAppearance::Tab: {
+      if (IsBottomTab(aFrame)) {
+        aGtkWidgetType = MOZ_GTK_TAB_BOTTOM;
+      } else {
+        aGtkWidgetType = MOZ_GTK_TAB_TOP;
+      }
+
+      if (aWidgetFlags) {
+        /* First bits will be used to store max(0,-bmargin) where bmargin
+         * is the bottom margin of the tab in pixels  (resp. top margin,
+         * for bottom tabs). */
+        *aWidgetFlags = GetTabMarginPixels(aFrame);
+
+        if (IsSelectedTab(aFrame)) *aWidgetFlags |= MOZ_GTK_TAB_SELECTED;
+
+        if (IsFirstTab(aFrame)) *aWidgetFlags |= MOZ_GTK_TAB_FIRST;
+      }
+    } break;
+    case StyleAppearance::Splitter:
+      if (IsHorizontal(aFrame))
+        aGtkWidgetType = MOZ_GTK_SPLITTER_VERTICAL;
+      else
+        aGtkWidgetType = MOZ_GTK_SPLITTER_HORIZONTAL;
+      break;
+    case StyleAppearance::MozWindowTitlebar:
+      aGtkWidgetType = MOZ_GTK_HEADER_BAR;
+      break;
+    case StyleAppearance::MozWindowDecorations:
+      aGtkWidgetType = MOZ_GTK_WINDOW_DECORATION;
+      break;
+    case StyleAppearance::MozWindowTitlebarMaximized:
+      aGtkWidgetType = MOZ_GTK_HEADER_BAR_MAXIMIZED;
+      break;
+    case StyleAppearance::MozWindowButtonBox:
+      aGtkWidgetType = MOZ_GTK_HEADER_BAR_BUTTON_BOX;
+      break;
+    case StyleAppearance::MozWindowButtonClose:
+      aGtkWidgetType = MOZ_GTK_HEADER_BAR_BUTTON_CLOSE;
+      break;
+    case StyleAppearance::MozWindowButtonMinimize:
+      aGtkWidgetType = MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE;
+      break;
+    case StyleAppearance::MozWindowButtonMaximize:
+      aGtkWidgetType = MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE;
+      break;
+    case StyleAppearance::MozWindowButtonRestore:
+      aGtkWidgetType = MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE_RESTORE;
+      break;
+    default:
+      return false;
+  }
+
+  return true;
+}
+
+class SystemCairoClipper : public ClipExporter {
+ public:
+  explicit SystemCairoClipper(cairo_t* aContext, gint aScaleFactor = 1)
+      : mContext(aContext), mScaleFactor(aScaleFactor) {}
+
+  void BeginClip(const Matrix& aTransform) override {
+    cairo_matrix_t mat;
+    GfxMatrixToCairoMatrix(aTransform, mat);
+    // We also need to remove the scale factor effect from the matrix
+    mat.y0 = mat.y0 / mScaleFactor;
+    mat.x0 = mat.x0 / mScaleFactor;
+    cairo_set_matrix(mContext, &mat);
+
+    cairo_new_path(mContext);
+  }
+
+  void MoveTo(const Point& aPoint) override {
+    cairo_move_to(mContext, aPoint.x / mScaleFactor, aPoint.y / mScaleFactor);
+    mBeginPoint = aPoint;
+    mCurrentPoint = aPoint;
+  }
+
+  void LineTo(const Point& aPoint) override {
+    cairo_line_to(mContext, aPoint.x / mScaleFactor, aPoint.y / mScaleFactor);
+    mCurrentPoint = aPoint;
+  }
+
+  void BezierTo(const Point& aCP1, const Point& aCP2,
+                const Point& aCP3) override {
+    cairo_curve_to(mContext, aCP1.x / mScaleFactor, aCP1.y / mScaleFactor,
+                   aCP2.x / mScaleFactor, aCP2.y / mScaleFactor,
+                   aCP3.x / mScaleFactor, aCP3.y / mScaleFactor);
+    mCurrentPoint = aCP3;
+  }
+
+  void QuadraticBezierTo(const Point& aCP1, const Point& aCP2) override {
+    Point CP0 = CurrentPoint();
+    Point CP1 = (CP0 + aCP1 * 2.0) / 3.0;
+    Point CP2 = (aCP2 + aCP1 * 2.0) / 3.0;
+    Point CP3 = aCP2;
+    cairo_curve_to(mContext, CP1.x / mScaleFactor, CP1.y / mScaleFactor,
+                   CP2.x / mScaleFactor, CP2.y / mScaleFactor,
+                   CP3.x / mScaleFactor, CP3.y / mScaleFactor);
+    mCurrentPoint = aCP2;
+  }
+
+  void Arc(const Point& aOrigin, float aRadius, float aStartAngle,
+           float aEndAngle, bool aAntiClockwise) override {
+    ArcToBezier(this, aOrigin, Size(aRadius, aRadius), aStartAngle, aEndAngle,
+                aAntiClockwise);
+  }
+
+  void Close() override {
+    cairo_close_path(mContext);
+    mCurrentPoint = mBeginPoint;
+  }
+
+  void EndClip() override { cairo_clip(mContext); }
+
+ private:
+  cairo_t* mContext;
+  gint mScaleFactor;
+};
+
+static void DrawThemeWithCairo(gfxContext* aContext, DrawTarget* aDrawTarget,
+                               GtkWidgetState aState,
+                               WidgetNodeType aGTKWidgetType, gint aFlags,
+                               GtkTextDirection aDirection, double aScaleFactor,
+                               bool aSnapped, const Point& aDrawOrigin,
+                               const nsIntSize& aDrawSize,
+                               GdkRectangle& aGDKRect,
+                               nsITheme::Transparency aTransparency) {
+  static auto sCairoSurfaceSetDeviceScalePtr =
+      (void (*)(cairo_surface_t*, double, double))dlsym(
+          RTLD_DEFAULT, "cairo_surface_set_device_scale");
+  const bool useHiDPIWidgets =
+      aScaleFactor != 1.0 && sCairoSurfaceSetDeviceScalePtr;
+
+  Point drawOffsetScaled;
+  Point drawOffsetOriginal;
+  Matrix transform;
+  if (!aSnapped) {
+    // If we are not snapped, we depend on the DT for translation.
+    drawOffsetOriginal = aDrawOrigin;
+    drawOffsetScaled = useHiDPIWidgets ? drawOffsetOriginal / aScaleFactor
+                                       : drawOffsetOriginal;
+    transform = aDrawTarget->GetTransform().PreTranslate(drawOffsetScaled);
+  } else {
+    // Otherwise, we only need to take the device offset into account.
+    drawOffsetOriginal = aDrawOrigin - aContext->GetDeviceOffset();
+    drawOffsetScaled = useHiDPIWidgets ? drawOffsetOriginal / aScaleFactor
+                                       : drawOffsetOriginal;
+    transform = Matrix::Translation(drawOffsetScaled);
+  }
+
+  if (!useHiDPIWidgets && aScaleFactor != 1) {
+    transform.PreScale(aScaleFactor, aScaleFactor);
+  }
+
+  cairo_matrix_t mat;
+  GfxMatrixToCairoMatrix(transform, mat);
+
+  Size clipSize((aDrawSize.width + aScaleFactor - 1) / aScaleFactor,
+                (aDrawSize.height + aScaleFactor - 1) / aScaleFactor);
+
+  // A direct Cairo draw target is not available, so we need to create a
+  // temporary one.
+#if defined(MOZ_X11) && defined(CAIRO_HAS_XLIB_SURFACE)
+  if (GdkIsX11Display()) {
+    // If using a Cairo xlib surface, then try to reuse it.
+    BorrowedXlibDrawable borrow(aDrawTarget);
+    if (Drawable drawable = borrow.GetDrawable()) {
+      nsIntSize size = borrow.GetSize();
+      cairo_surface_t* surf = cairo_xlib_surface_create(
+          borrow.GetDisplay(), drawable, borrow.GetVisual(), size.width,
+          size.height);
+      if (!NS_WARN_IF(!surf)) {
+        Point offset = borrow.GetOffset();
+        if (offset != Point()) {
+          cairo_surface_set_device_offset(surf, offset.x, offset.y);
+        }
+        cairo_t* cr = cairo_create(surf);
+        if (!NS_WARN_IF(!cr)) {
+          RefPtr<SystemCairoClipper> clipper = new SystemCairoClipper(cr);
+          aContext->ExportClip(*clipper);
+
+          cairo_set_matrix(cr, &mat);
+
+          cairo_new_path(cr);
+          cairo_rectangle(cr, 0, 0, clipSize.width, clipSize.height);
+          cairo_clip(cr);
+
+          moz_gtk_widget_paint(aGTKWidgetType, cr, &aGDKRect, &aState, aFlags,
+                               aDirection);
+
+          cairo_destroy(cr);
+        }
+        cairo_surface_destroy(surf);
+      }
+      borrow.Finish();
+      return;
+    }
+  }
+#endif
+
+  // Check if the widget requires complex masking that must be composited.
+  // Try to directly write to the draw target's pixels if possible.
+  uint8_t* data;
+  nsIntSize size;
+  int32_t stride;
+  SurfaceFormat format;
+  IntPoint origin;
+  if (aDrawTarget->LockBits(&data, &size, &stride, &format, &origin)) {
+    // Create a Cairo image surface context the device rectangle.
+    cairo_surface_t* surf = cairo_image_surface_create_for_data(
+        data, GfxFormatToCairoFormat(format), size.width, size.height, stride);
+    if (!NS_WARN_IF(!surf)) {
+      if (useHiDPIWidgets) {
+        sCairoSurfaceSetDeviceScalePtr(surf, aScaleFactor, aScaleFactor);
+      }
+      if (origin != IntPoint()) {
+        cairo_surface_set_device_offset(surf, -origin.x, -origin.y);
+      }
+      cairo_t* cr = cairo_create(surf);
+      if (!NS_WARN_IF(!cr)) {
+        RefPtr<SystemCairoClipper> clipper =
+            new SystemCairoClipper(cr, useHiDPIWidgets ? aScaleFactor : 1);
+        aContext->ExportClip(*clipper);
+
+        cairo_set_matrix(cr, &mat);
+
+        cairo_new_path(cr);
+        cairo_rectangle(cr, 0, 0, clipSize.width, clipSize.height);
+        cairo_clip(cr);
+
+        moz_gtk_widget_paint(aGTKWidgetType, cr, &aGDKRect, &aState, aFlags,
+                             aDirection);
+
+        cairo_destroy(cr);
+      }
+      cairo_surface_destroy(surf);
+    }
+    aDrawTarget->ReleaseBits(data);
+  } else {
+    // If the widget has any transparency, make sure to choose an alpha format.
+    format = aTransparency != nsITheme::eOpaque ? SurfaceFormat::B8G8R8A8
+                                                : aDrawTarget->GetFormat();
+    // Create a temporary data surface to render the widget into.
+    RefPtr<DataSourceSurface> dataSurface = Factory::CreateDataSourceSurface(
+        aDrawSize, format, aTransparency != nsITheme::eOpaque);
+    DataSourceSurface::MappedSurface map;
+    if (!NS_WARN_IF(
+            !(dataSurface &&
+              dataSurface->Map(DataSourceSurface::MapType::WRITE, &map)))) {
+      // Create a Cairo image surface wrapping the data surface.
+      cairo_surface_t* surf = cairo_image_surface_create_for_data(
+          map.mData, GfxFormatToCairoFormat(format), aDrawSize.width,
+          aDrawSize.height, map.mStride);
+      cairo_t* cr = nullptr;
+      if (!NS_WARN_IF(!surf)) {
+        cr = cairo_create(surf);
+        if (!NS_WARN_IF(!cr)) {
+          if (aScaleFactor != 1) {
+            if (useHiDPIWidgets) {
+              sCairoSurfaceSetDeviceScalePtr(surf, aScaleFactor, aScaleFactor);
+            } else {
+              cairo_scale(cr, aScaleFactor, aScaleFactor);
+            }
+          }
+
+          moz_gtk_widget_paint(aGTKWidgetType, cr, &aGDKRect, &aState, aFlags,
+                               aDirection);
+        }
+      }
+
+      // Unmap the surface before using it as a source
+      dataSurface->Unmap();
+
+      if (cr) {
+        // The widget either needs to be masked or has transparency, so use the
+        // slower drawing path.
+        aDrawTarget->DrawSurface(
+            dataSurface,
+            Rect(aSnapped ? drawOffsetOriginal -
+                                aDrawTarget->GetTransform().GetTranslation()
+                          : drawOffsetOriginal,
+                 Size(aDrawSize)),
+            Rect(0, 0, aDrawSize.width, aDrawSize.height));
+        cairo_destroy(cr);
+      }
+
+      if (surf) {
+        cairo_surface_destroy(surf);
+      }
+    }
+  }
+}
+
+CSSIntMargin nsNativeThemeGTK::GetExtraSizeForWidget(
+    nsIFrame* aFrame, StyleAppearance aAppearance) {
+  CSSIntMargin extra;
+  // Allow an extra one pixel above and below the thumb for certain
+  // GTK2 themes (Ximian Industrial, Bluecurve, Misty, at least);
+  // We modify the frame's overflow area.  See bug 297508.
+  switch (aAppearance) {
+    case StyleAppearance::Button: {
+      if (IsDefaultButton(aFrame)) {
+        // Some themes draw a default indicator outside the widget,
+        // include that in overflow
+        moz_gtk_button_get_default_overflow(&extra.top.value, &extra.left.value,
+                                            &extra.bottom.value,
+                                            &extra.right.value);
+        break;
+      }
+      return {};
+    }
+    default:
+      return {};
+  }
+  return extra;
+}
+
+bool nsNativeThemeGTK::IsWidgetVisible(StyleAppearance aAppearance) {
+  switch (aAppearance) {
+    case StyleAppearance::MozWindowButtonBox:
+      return false;
+    default:
+      break;
+  }
+  return true;
+}
+
+NS_IMETHODIMP
+nsNativeThemeGTK::DrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
+                                       StyleAppearance aAppearance,
+                                       const nsRect& aRect,
+                                       const nsRect& aDirtyRect,
+                                       DrawOverflow aDrawOverflow) {
+  if (IsWidgetNonNative(aFrame, aAppearance) != NonNative::No) {
+    return Theme::DrawWidgetBackground(aContext, aFrame, aAppearance, aRect,
+                                       aDirtyRect, aDrawOverflow);
+  }
+
+  GtkWidgetState state;
+  WidgetNodeType gtkWidgetType;
+  GtkTextDirection direction = GetTextDirection(aFrame);
+  gint flags;
+
+  if (!IsWidgetVisible(aAppearance) ||
+      !GetGtkWidgetAndState(aAppearance, aFrame, gtkWidgetType, &state,
+                            &flags)) {
+    return NS_OK;
+  }
+
+  gfxContext* ctx = aContext;
+  nsPresContext* presContext = aFrame->PresContext();
+
+  gfxRect rect = presContext->AppUnitsToGfxUnits(aRect);
+  gfxRect dirtyRect = presContext->AppUnitsToGfxUnits(aDirtyRect);
+
+  // Align to device pixels where sensible
+  // to provide crisper and faster drawing.
+  // Don't snap if it's a non-unit scale factor. We're going to have to take
+  // slow paths then in any case.
+  // We prioritize the size when snapping in order to avoid distorting widgets
+  // that should be square, which can occur if edges are snapped independently.
+  bool snapped = ctx->UserToDevicePixelSnapped(
+      rect, gfxContext::SnapOption::PrioritizeSize);
+  if (snapped) {
+    // Leave rect in device coords but make dirtyRect consistent.
+    dirtyRect = ctx->UserToDevice(dirtyRect);
+  }
+
+  // Translate the dirty rect so that it is wrt the widget top-left.
+  dirtyRect.MoveBy(-rect.TopLeft());
+  // Round out the dirty rect to gdk pixels to ensure that gtk draws
+  // enough pixels for interpolation to device pixels.
+  dirtyRect.RoundOut();
+
+  // GTK themes can only draw an integer number of pixels
+  // (even when not snapped).
+  LayoutDeviceIntRect widgetRect(0, 0, NS_lround(rect.Width()),
+                                 NS_lround(rect.Height()));
+
+  // This is the rectangle that will actually be drawn, in gdk pixels
+  LayoutDeviceIntRect drawingRect(
+      int32_t(dirtyRect.X()), int32_t(dirtyRect.Y()),
+      int32_t(dirtyRect.Width()), int32_t(dirtyRect.Height()));
+  if (widgetRect.IsEmpty() ||
+      !drawingRect.IntersectRect(widgetRect, drawingRect)) {
+    return NS_OK;
+  }
+
+  NS_ASSERTION(!IsWidgetTypeDisabled(mDisabledWidgetTypes, aAppearance),
+               "Trying to render an unsafe widget!");
+
+  bool safeState = IsWidgetStateSafe(mSafeWidgetStates, aAppearance, &state);
+  if (!safeState) {
+    gLastGdkError = 0;
+    gdk_error_trap_push();
+  }
+
+  Transparency transparency = GetWidgetTransparency(aFrame, aAppearance);
+
+  // gdk rectangles are wrt the drawing rect.
+  auto scaleFactor = GetWidgetScaleFactor(aFrame);
+  LayoutDeviceIntRect gdkDevRect(-drawingRect.TopLeft(), widgetRect.Size());
+
+  auto gdkCssRect = CSSIntRect::RoundIn(gdkDevRect / scaleFactor);
+  GdkRectangle gdk_rect = {gdkCssRect.x, gdkCssRect.y, gdkCssRect.width,
+                           gdkCssRect.height};
+
+  // Save actual widget scale to GtkWidgetState as we don't provide
+  // the frame to gtk3drawing routines.
+  state.image_scale = std::ceil(scaleFactor.scale);
+
+  // translate everything so (0,0) is the top left of the drawingRect
+  gfxPoint origin = rect.TopLeft() + drawingRect.TopLeft().ToUnknownPoint();
+
+  DrawThemeWithCairo(ctx, aContext->GetDrawTarget(), state, gtkWidgetType,
+                     flags, direction, scaleFactor.scale, snapped,
+                     ToPoint(origin), drawingRect.Size().ToUnknownSize(),
+                     gdk_rect, transparency);
+
+  if (!safeState) {
+    // gdk_flush() call from expose event crashes Gtk+ on Wayland
+    // (Gnome BZ #773307)
+    if (GdkIsX11Display()) {
+      gdk_flush();
+    }
+    gLastGdkError = gdk_error_trap_pop();
+
+    if (gLastGdkError) {
+#ifdef DEBUG
+      printf(
+          "GTK theme failed for widget type %d, error was %d, state was "
+          "[active=%d,focused=%d,inHover=%d,disabled=%d]\n",
+          static_cast<int>(aAppearance), gLastGdkError, state.active,
+          state.focused, state.inHover, state.disabled);
+#endif
+      NS_WARNING("GTK theme failed; disabling unsafe widget");
+      SetWidgetTypeDisabled(mDisabledWidgetTypes, aAppearance);
+      // force refresh of the window, because the widget was not
+      // successfully drawn it must be redrawn using the default look
+      RefreshWidgetWindow(aFrame);
+    } else {
+      SetWidgetStateSafe(mSafeWidgetStates, aAppearance, &state);
+    }
+  }
+
+  // Indeterminate progress bar are animated.
+  if (gtkWidgetType == MOZ_GTK_PROGRESS_CHUNK_INDETERMINATE ||
+      gtkWidgetType == MOZ_GTK_PROGRESS_CHUNK_VERTICAL_INDETERMINATE) {
+    if (!QueueAnimatedContentForRefresh(aFrame->GetContent(), 30)) {
+      NS_WARNING("unable to animate widget!");
+    }
+  }
+
+  return NS_OK;
+}
+
+bool nsNativeThemeGTK::CreateWebRenderCommandsForWidget(
+    mozilla::wr::DisplayListBuilder& aBuilder,
+    mozilla::wr::IpcResourceUpdateQueue& aResources,
+    const mozilla::layers::StackingContextHelper& aSc,
+    mozilla::layers::RenderRootStateManager* aManager, nsIFrame* aFrame,
+    StyleAppearance aAppearance, const nsRect& aRect) {
+  if (IsWidgetNonNative(aFrame, aAppearance) != NonNative::No) {
+    return Theme::CreateWebRenderCommandsForWidget(
+        aBuilder, aResources, aSc, aManager, aFrame, aAppearance, aRect);
+  }
+  return false;
+}
+
+WidgetNodeType nsNativeThemeGTK::NativeThemeToGtkTheme(
+    StyleAppearance aAppearance, nsIFrame* aFrame) {
+  WidgetNodeType gtkWidgetType;
+  gint unusedFlags;
+
+  if (!GetGtkWidgetAndState(aAppearance, aFrame, gtkWidgetType, nullptr,
+                            &unusedFlags)) {
+    MOZ_ASSERT_UNREACHABLE("Unknown native widget to gtk widget mapping");
+    return MOZ_GTK_WINDOW;
+  }
+  return gtkWidgetType;
+}
+
+static void FixupForVerticalWritingMode(WritingMode aWritingMode,
+                                        CSSIntMargin* aResult) {
+  if (aWritingMode.IsVertical()) {
+    bool rtl = aWritingMode.IsBidiRTL();
+    LogicalMargin logical(aWritingMode, aResult->top,
+                          rtl ? aResult->left : aResult->right, aResult->bottom,
+                          rtl ? aResult->right : aResult->left);
+    nsMargin physical = logical.GetPhysicalMargin(aWritingMode);
+    aResult->top = physical.top;
+    aResult->right = physical.right;
+    aResult->bottom = physical.bottom;
+    aResult->left = physical.left;
+  }
+}
+
+CSSIntMargin nsNativeThemeGTK::GetCachedWidgetBorder(
+    nsIFrame* aFrame, StyleAppearance aAppearance,
+    GtkTextDirection aDirection) {
+  CSSIntMargin result;
+
+  WidgetNodeType gtkWidgetType;
+  gint unusedFlags;
+  if (GetGtkWidgetAndState(aAppearance, aFrame, gtkWidgetType, nullptr,
+                           &unusedFlags)) {
+    MOZ_ASSERT(0 <= gtkWidgetType && gtkWidgetType < MOZ_GTK_WIDGET_NODE_COUNT);
+    uint8_t cacheIndex = gtkWidgetType / 8;
+    uint8_t cacheBit = 1u << (gtkWidgetType % 8);
+
+    if (mBorderCacheValid[cacheIndex] & cacheBit) {
+      result = mBorderCache[gtkWidgetType];
+    } else {
+      moz_gtk_get_widget_border(gtkWidgetType, &result.left.value,
+                                &result.top.value, &result.right.value,
+                                &result.bottom.value, aDirection);
+      if (gtkWidgetType != MOZ_GTK_DROPDOWN) {  // depends on aDirection
+        mBorderCacheValid[cacheIndex] |= cacheBit;
+        mBorderCache[gtkWidgetType] = result;
+      }
+    }
+  }
+  FixupForVerticalWritingMode(aFrame->GetWritingMode(), &result);
+  return result;
+}
+
+LayoutDeviceIntMargin nsNativeThemeGTK::GetWidgetBorder(
+    nsDeviceContext* aContext, nsIFrame* aFrame, StyleAppearance aAppearance) {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return Theme::GetWidgetBorder(aContext, aFrame, aAppearance);
+  }
+
+  CSSIntMargin result;
+  GtkTextDirection direction = GetTextDirection(aFrame);
+  switch (aAppearance) {
+    case StyleAppearance::Toolbox:
+      // gtk has no toolbox equivalent.  So, although we map toolbox to
+      // gtk's 'toolbar' for purposes of painting the widget background,
+      // we don't use the toolbar border for toolbox.
+      break;
+    case StyleAppearance::Dualbutton:
+      // TOOLBAR_DUAL_BUTTON is an interesting case.  We want a border to draw
+      // around the entire button + dropdown, and also an inner border if you're
+      // over the button part.  But, we want the inner button to be right up
+      // against the edge of the outer button so that the borders overlap.
+      // To make this happen, we draw a button border for the outer button,
+      // but don't reserve any space for it.
+      break;
+    case StyleAppearance::Tab: {
+      WidgetNodeType gtkWidgetType;
+      gint flags;
+
+      if (!GetGtkWidgetAndState(aAppearance, aFrame, gtkWidgetType, nullptr,
+                                &flags)) {
+        return {};
+      }
+      moz_gtk_get_tab_border(&result.left.value, &result.top.value,
+                             &result.right.value, &result.bottom.value,
+                             direction, (GtkTabFlags)flags, gtkWidgetType);
+    } break;
+    default: {
+      result = GetCachedWidgetBorder(aFrame, aAppearance, direction);
+    }
+  }
+
+  return (CSSMargin(result) * GetWidgetScaleFactor(aFrame)).Rounded();
+}
+
+bool nsNativeThemeGTK::GetWidgetPadding(nsDeviceContext* aContext,
+                                        nsIFrame* aFrame,
+                                        StyleAppearance aAppearance,
+                                        LayoutDeviceIntMargin* aResult) {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return Theme::GetWidgetPadding(aContext, aFrame, aAppearance, aResult);
+  }
+  switch (aAppearance) {
+    case StyleAppearance::Toolbarbutton:
+    case StyleAppearance::Tooltip:
+    case StyleAppearance::MozWindowButtonBox:
+    case StyleAppearance::MozWindowButtonClose:
+    case StyleAppearance::MozWindowButtonMinimize:
+    case StyleAppearance::MozWindowButtonMaximize:
+    case StyleAppearance::MozWindowButtonRestore:
+    case StyleAppearance::Dualbutton:
+    case StyleAppearance::TabScrollArrowBack:
+    case StyleAppearance::TabScrollArrowForward:
+    case StyleAppearance::ToolbarbuttonDropdown:
+    case StyleAppearance::ButtonArrowUp:
+    case StyleAppearance::ButtonArrowDown:
+    case StyleAppearance::ButtonArrowNext:
+    case StyleAppearance::ButtonArrowPrevious:
+    case StyleAppearance::RangeThumb:
+    // Radios and checkboxes return a fixed size in GetMinimumWidgetSize
+    // and have a meaningful baseline, so they can't have
+    // author-specified padding.
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Radio:
+      aResult->SizeTo(0, 0, 0, 0);
+      return true;
+    default:
+      break;
+  }
+
+  return false;
+}
+
+bool nsNativeThemeGTK::GetWidgetOverflow(nsDeviceContext* aContext,
+                                         nsIFrame* aFrame,
+                                         StyleAppearance aAppearance,
+                                         nsRect* aOverflowRect) {
+  if (IsWidgetNonNative(aFrame, aAppearance) != NonNative::No) {
+    return Theme::GetWidgetOverflow(aContext, aFrame, aAppearance,
+                                    aOverflowRect);
+  }
+  auto overflow = GetExtraSizeForWidget(aFrame, aAppearance);
+  if (overflow == CSSIntMargin()) {
+    return false;
+  }
+  aOverflowRect->Inflate(CSSIntMargin::ToAppUnits(overflow));
+  return true;
+}
+
+auto nsNativeThemeGTK::IsWidgetNonNative(nsIFrame* aFrame,
+                                         StyleAppearance aAppearance)
+    -> NonNative {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return NonNative::Always;
+  }
+
+  // If the current GTK theme color scheme matches our color-scheme, then we
+  // can draw a native widget.
+  if (LookAndFeel::ColorSchemeForFrame(aFrame) ==
+      PreferenceSheet::ColorSchemeForChrome()) {
+    return NonNative::No;
+  }
+
+  // As an special-case, for tooltips, we check if the tooltip color is the
+  // same between the light and dark themes. If so we can get away with drawing
+  // the native widget, see bug 1817396.
+  if (aAppearance == StyleAppearance::Tooltip) {
+    auto darkColor =
+        LookAndFeel::Color(StyleSystemColor::Infotext, ColorScheme::Dark,
+                           LookAndFeel::UseStandins::No);
+    auto lightColor =
+        LookAndFeel::Color(StyleSystemColor::Infotext, ColorScheme::Light,
+                           LookAndFeel::UseStandins::No);
+    if (darkColor == lightColor) {
+      return NonNative::No;
+    }
+  }
+
+  // If the non-native theme doesn't support the widget then oh well...
+  if (!Theme::ThemeSupportsWidget(aFrame->PresContext(), aFrame, aAppearance)) {
+    return NonNative::No;
+  }
+
+  return NonNative::BecauseColorMismatch;
+}
+
+bool nsNativeThemeGTK::IsWidgetAlwaysNonNative(nsIFrame* aFrame,
+                                               StyleAppearance aAppearance) {
+  return Theme::IsWidgetAlwaysNonNative(aFrame, aAppearance) ||
+         aAppearance == StyleAppearance::MozMenulistArrowButton;
+}
+
+LayoutDeviceIntSize nsNativeThemeGTK::GetMinimumWidgetSize(
+    nsPresContext* aPresContext, nsIFrame* aFrame,
+    StyleAppearance aAppearance) {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return Theme::GetMinimumWidgetSize(aPresContext, aFrame, aAppearance);
+  }
+
+  CSSIntSize result;
+  switch (aAppearance) {
+    case StyleAppearance::Splitter: {
+      if (IsHorizontal(aFrame)) {
+        moz_gtk_splitter_get_metrics(GTK_ORIENTATION_HORIZONTAL, &result.width);
+      } else {
+        moz_gtk_splitter_get_metrics(GTK_ORIENTATION_VERTICAL, &result.height);
+      }
+    } break;
+    case StyleAppearance::RangeThumb: {
+      if (IsRangeHorizontal(aFrame)) {
+        moz_gtk_get_scalethumb_metrics(GTK_ORIENTATION_HORIZONTAL,
+                                       &result.width, &result.height);
+      } else {
+        moz_gtk_get_scalethumb_metrics(GTK_ORIENTATION_VERTICAL, &result.width,
+                                       &result.width);
+      }
+    } break;
+    case StyleAppearance::TabScrollArrowBack:
+    case StyleAppearance::TabScrollArrowForward: {
+      moz_gtk_get_tab_scroll_arrow_size(&result.width, &result.height);
+    } break;
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Radio: {
+      const ToggleGTKMetrics* metrics = GetToggleMetrics(
+          aAppearance == StyleAppearance::Radio ? MOZ_GTK_RADIOBUTTON
+                                                : MOZ_GTK_CHECKBUTTON);
+      result.width = metrics->minSizeWithBorder.width;
+      result.height = metrics->minSizeWithBorder.height;
+    } break;
+    case StyleAppearance::ToolbarbuttonDropdown:
+    case StyleAppearance::ButtonArrowUp:
+    case StyleAppearance::ButtonArrowDown:
+    case StyleAppearance::ButtonArrowNext:
+    case StyleAppearance::ButtonArrowPrevious: {
+      moz_gtk_get_arrow_size(MOZ_GTK_TOOLBARBUTTON_ARROW, &result.width,
+                             &result.height);
+    } break;
+    case StyleAppearance::MozWindowButtonClose: {
+      const ToolbarButtonGTKMetrics* metrics =
+          GetToolbarButtonMetrics(MOZ_GTK_HEADER_BAR_BUTTON_CLOSE);
+      result.width = metrics->minSizeWithBorderMargin.width;
+      result.height = metrics->minSizeWithBorderMargin.height;
+      break;
+    }
+    case StyleAppearance::MozWindowButtonMinimize: {
+      const ToolbarButtonGTKMetrics* metrics =
+          GetToolbarButtonMetrics(MOZ_GTK_HEADER_BAR_BUTTON_MINIMIZE);
+      result.width = metrics->minSizeWithBorderMargin.width;
+      result.height = metrics->minSizeWithBorderMargin.height;
+      break;
+    }
+    case StyleAppearance::MozWindowButtonMaximize:
+    case StyleAppearance::MozWindowButtonRestore: {
+      const ToolbarButtonGTKMetrics* metrics =
+          GetToolbarButtonMetrics(MOZ_GTK_HEADER_BAR_BUTTON_MAXIMIZE);
+      result.width = metrics->minSizeWithBorderMargin.width;
+      result.height = metrics->minSizeWithBorderMargin.height;
+      break;
+    }
+    case StyleAppearance::Button:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton: {
+      if (aAppearance == StyleAppearance::Menulist ||
+          aAppearance == StyleAppearance::MenulistButton) {
+        // Include the arrow size.
+        moz_gtk_get_arrow_size(MOZ_GTK_DROPDOWN, &result.width, &result.height);
+      }
+      // else the minimum size is missing consideration of container
+      // descendants; the value returned here will not be helpful, but the
+      // box model may consider border and padding with child minimum sizes.
+
+      CSSIntMargin border =
+          GetCachedWidgetBorder(aFrame, aAppearance, GetTextDirection(aFrame));
+      result.width += border.LeftRight();
+      result.height += border.TopBottom();
+    } break;
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield: {
+      gint contentHeight = 0;
+      gint borderPaddingHeight = 0;
+      moz_gtk_get_entry_min_height(&contentHeight, &borderPaddingHeight);
+
+      // Scale the min content height proportionately with the font-size if it's
+      // smaller than the default one. This prevents <input type=text
+      // style="font-size: .5em"> from keeping a ridiculously large size, for
+      // example.
+      const gfxFloat fieldFontSizeInCSSPixels = [] {
+        gfxFontStyle fieldFontStyle;
+        nsAutoString unusedFontName;
+        DebugOnly<bool> result = LookAndFeel::GetFont(
+            LookAndFeel::FontID::MozField, unusedFontName, fieldFontStyle);
+        MOZ_ASSERT(result, "GTK look and feel supports the field font");
+        // NOTE: GetFont returns font sizes in CSS pixels, and we want just
+        // that.
+        return fieldFontStyle.size;
+      }();
+
+      const gfxFloat fontSize = aFrame->StyleFont()->mFont.size.ToCSSPixels();
+      if (fieldFontSizeInCSSPixels > fontSize) {
+        contentHeight =
+            std::round(contentHeight * fontSize / fieldFontSizeInCSSPixels);
+      }
+
+      gint height = contentHeight + borderPaddingHeight;
+      if (aFrame->GetWritingMode().IsVertical()) {
+        result.width = height;
+      } else {
+        result.height = height;
+      }
+    } break;
+    case StyleAppearance::Spinner:
+      // hard code these sizes
+      result.width = 14;
+      result.height = 26;
+      break;
+    case StyleAppearance::SpinnerUpbutton:
+    case StyleAppearance::SpinnerDownbutton:
+      // hard code these sizes
+      result.width = 14;
+      result.height = 13;
+      break;
+    case StyleAppearance::Treetwisty:
+    case StyleAppearance::Treetwistyopen: {
+      gint expander_size;
+      moz_gtk_get_treeview_expander_size(&expander_size);
+      result.width = result.height = expander_size;
+    } break;
+    default:
+      break;
+  }
+
+  return LayoutDeviceIntSize::Round(CSSSize(result) *
+                                    GetWidgetScaleFactor(aFrame));
+}
+
+NS_IMETHODIMP
+nsNativeThemeGTK::WidgetStateChanged(nsIFrame* aFrame,
+                                     StyleAppearance aAppearance,
+                                     nsAtom* aAttribute, bool* aShouldRepaint,
+                                     const nsAttrValue* aOldValue) {
+  *aShouldRepaint = false;
+
+  if (IsWidgetNonNative(aFrame, aAppearance) != NonNative::No) {
+    return Theme::WidgetStateChanged(aFrame, aAppearance, aAttribute,
+                                     aShouldRepaint, aOldValue);
+  }
+
+  // Some widget types just never change state.
+  if (aAppearance == StyleAppearance::Toolbox ||
+      aAppearance == StyleAppearance::Toolbar ||
+      aAppearance == StyleAppearance::Progresschunk ||
+      aAppearance == StyleAppearance::ProgressBar ||
+      aAppearance == StyleAppearance::Tooltip ||
+      aAppearance == StyleAppearance::MozWindowDecorations) {
+    return NS_OK;
+  }
+
+  if (aAppearance == StyleAppearance::MozWindowTitlebar ||
+      aAppearance == StyleAppearance::MozWindowTitlebarMaximized ||
+      aAppearance == StyleAppearance::MozWindowButtonClose ||
+      aAppearance == StyleAppearance::MozWindowButtonMinimize ||
+      aAppearance == StyleAppearance::MozWindowButtonMaximize ||
+      aAppearance == StyleAppearance::MozWindowButtonRestore) {
+    *aShouldRepaint = true;
+    return NS_OK;
+  }
+
+  // XXXdwh Not sure what can really be done here.  Can at least guess for
+  // specific widgets that they're highly unlikely to have certain states.
+  // For example, a toolbar doesn't care about any states.
+  if (!aAttribute) {
+    // Hover/focus/active changed.  Always repaint.
+    *aShouldRepaint = true;
+    return NS_OK;
+  }
+
+  // Check the attribute to see if it's relevant.
+  // disabled, checked, dlgtype, default, etc.
+  *aShouldRepaint = false;
+  if (aAttribute == nsGkAtoms::disabled || aAttribute == nsGkAtoms::checked ||
+      aAttribute == nsGkAtoms::selected ||
+      aAttribute == nsGkAtoms::visuallyselected ||
+      aAttribute == nsGkAtoms::focused || aAttribute == nsGkAtoms::readonly ||
+      aAttribute == nsGkAtoms::_default ||
+      aAttribute == nsGkAtoms::menuactive || aAttribute == nsGkAtoms::open) {
+    *aShouldRepaint = true;
+    return NS_OK;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNativeThemeGTK::ThemeChanged() {
+  memset(mDisabledWidgetTypes, 0, sizeof(mDisabledWidgetTypes));
+  memset(mSafeWidgetStates, 0, sizeof(mSafeWidgetStates));
+  memset(mBorderCacheValid, 0, sizeof(mBorderCacheValid));
+  return NS_OK;
+}
+
+NS_IMETHODIMP_(bool)
+nsNativeThemeGTK::ThemeSupportsWidget(nsPresContext* aPresContext,
+                                      nsIFrame* aFrame,
+                                      StyleAppearance aAppearance) {
+  if (IsWidgetTypeDisabled(mDisabledWidgetTypes, aAppearance)) {
+    return false;
+  }
+
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return Theme::ThemeSupportsWidget(aPresContext, aFrame, aAppearance);
+  }
+
+  switch (aAppearance) {
+    // Combobox dropdowns don't support native theming in vertical mode.
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+      if (aFrame && aFrame->GetWritingMode().IsVertical()) {
+        return false;
+      }
+      [[fallthrough]];
+
+    case StyleAppearance::Button:
+    case StyleAppearance::Radio:
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Toolbox:  // N/A
+    case StyleAppearance::Toolbarbutton:
+    case StyleAppearance::Dualbutton:  // so we can override the border with 0
+    case StyleAppearance::ToolbarbuttonDropdown:
+    case StyleAppearance::ButtonArrowUp:
+    case StyleAppearance::ButtonArrowDown:
+    case StyleAppearance::ButtonArrowNext:
+    case StyleAppearance::ButtonArrowPrevious:
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Treeview:
+      // case StyleAppearance::Treeitem:
+    case StyleAppearance::Treetwisty:
+      // case StyleAppearance::Treeline:
+      // case StyleAppearance::Treeheader:
+    case StyleAppearance::Treetwistyopen:
+    case StyleAppearance::ProgressBar:
+    case StyleAppearance::Progresschunk:
+    case StyleAppearance::Tab:
+    // case StyleAppearance::Tabpanel:
+    case StyleAppearance::Tabpanels:
+    case StyleAppearance::TabScrollArrowBack:
+    case StyleAppearance::TabScrollArrowForward:
+    case StyleAppearance::Tooltip:
+    case StyleAppearance::Spinner:
+    case StyleAppearance::SpinnerUpbutton:
+    case StyleAppearance::SpinnerDownbutton:
+    case StyleAppearance::SpinnerTextfield:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Range:
+    case StyleAppearance::RangeThumb:
+    case StyleAppearance::Splitter:
+    case StyleAppearance::MozWindowButtonBox:
+    case StyleAppearance::MozWindowButtonClose:
+    case StyleAppearance::MozWindowButtonMinimize:
+    case StyleAppearance::MozWindowButtonMaximize:
+    case StyleAppearance::MozWindowButtonRestore:
+    case StyleAppearance::MozWindowTitlebar:
+    case StyleAppearance::MozWindowTitlebarMaximized:
+    case StyleAppearance::MozWindowDecorations:
+      return !IsWidgetStyled(aPresContext, aFrame, aAppearance);
+    default:
+      break;
+  }
+
+  return false;
+}
+
+NS_IMETHODIMP_(bool)
+nsNativeThemeGTK::WidgetIsContainer(StyleAppearance aAppearance) {
+  // XXXdwh At some point flesh all of this out.
+  if (aAppearance == StyleAppearance::Radio ||
+      aAppearance == StyleAppearance::RangeThumb ||
+      aAppearance == StyleAppearance::Checkbox ||
+      aAppearance == StyleAppearance::TabScrollArrowBack ||
+      aAppearance == StyleAppearance::TabScrollArrowForward ||
+      aAppearance == StyleAppearance::ButtonArrowUp ||
+      aAppearance == StyleAppearance::ButtonArrowDown ||
+      aAppearance == StyleAppearance::ButtonArrowNext ||
+      aAppearance == StyleAppearance::ButtonArrowPrevious)
+    return false;
+  return true;
+}
+
+bool nsNativeThemeGTK::ThemeDrawsFocusForWidget(nsIFrame* aFrame,
+                                                StyleAppearance aAppearance) {
+  if (IsWidgetNonNative(aFrame, aAppearance) != NonNative::No) {
+    return Theme::ThemeDrawsFocusForWidget(aFrame, aAppearance);
+  }
+  switch (aAppearance) {
+    case StyleAppearance::Checkbox:
+    case StyleAppearance::Radio:
+      // These are drawn only for non-XUL elements, but in XUL the label has
+      // the focus ring.
+      return true;
+    case StyleAppearance::Button:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::NumberInput:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool nsNativeThemeGTK::ThemeNeedsComboboxDropmarker() { return false; }
+
+nsITheme::Transparency nsNativeThemeGTK::GetWidgetTransparency(
+    nsIFrame* aFrame, StyleAppearance aAppearance) {
+  if (IsWidgetNonNative(aFrame, aAppearance) != NonNative::No) {
+    return Theme::GetWidgetTransparency(aFrame, aAppearance);
+  }
+
+  switch (aAppearance) {
+    // Tooltips use gtk_paint_flat_box() on Gtk2
+    // but are shaped on Gtk3
+    case StyleAppearance::Tooltip:
+      return eTransparent;
+    default:
+      return eUnknownTransparency;
+  }
+}
+
+already_AddRefed<Theme> do_CreateNativeThemeDoNotUseDirectly() {
+  if (gfxPlatform::IsHeadless()) {
+    return do_AddRef(new Theme(Theme::ScrollbarStyle()));
+  }
+  return do_AddRef(new nsNativeThemeGTK());
+}
diff --git a/widget/gtk/nsNativeThemeGTK.h b/widget/gtk/nsNativeThemeGTK.h
new file mode 100644
index 0000000000..2d0878290e
--- /dev/null
+++ b/widget/gtk/nsNativeThemeGTK.h
@@ -0,0 +1,119 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _GTK_NSNATIVETHEMEGTK_H_
+#define _GTK_NSNATIVETHEMEGTK_H_
+
+#include "nsITheme.h"
+#include "nsCOMPtr.h"
+#include "nsAtom.h"
+#include "Theme.h"
+
+#include <gtk/gtk.h>
+#include "gtkdrawing.h"
+
+class nsNativeThemeGTK final : public mozilla::widget::Theme {
+  using Theme = mozilla::widget::Theme;
+
+ public:
+  // The nsITheme interface.
+  NS_IMETHOD DrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
+                                  StyleAppearance aAppearance,
+                                  const nsRect& aRect, const nsRect& aDirtyRect,
+                                  DrawOverflow) override;
+
+  bool CreateWebRenderCommandsForWidget(
+      mozilla::wr::DisplayListBuilder& aBuilder,
+      mozilla::wr::IpcResourceUpdateQueue& aResources,
+      const mozilla::layers::StackingContextHelper& aSc,
+      mozilla::layers::RenderRootStateManager* aManager, nsIFrame*,
+      StyleAppearance, const nsRect& aRect) override;
+
+  [[nodiscard]] LayoutDeviceIntMargin GetWidgetBorder(
+      nsDeviceContext* aContext, nsIFrame* aFrame,
+      StyleAppearance aAppearance) override;
+
+  bool GetWidgetPadding(nsDeviceContext* aContext, nsIFrame* aFrame,
+                        StyleAppearance aAppearance,
+                        LayoutDeviceIntMargin* aResult) override;
+
+  bool GetWidgetOverflow(nsDeviceContext* aContext, nsIFrame* aFrame,
+                         StyleAppearance aAppearance,
+                         nsRect* aOverflowRect) override;
+
+  // Whether we draw a non-native widget.
+  //
+  // We always draw scrollbars as non-native so that all of Firefox has
+  // consistent scrollbar styles both in chrome and content (plus, the
+  // non-native scrollbars support scrollbar-width, auto-darkening...).
+  //
+  // We draw other widgets as non-native when their color-scheme doesn't match
+  // the current GTK theme's color-scheme. We do that because frequently
+  // switching GTK themes at runtime is prohibitively expensive. In that case
+  // (`BecauseColorMismatch`) we don't call into the non-native theme for sizing
+  // information (GetWidgetPadding/Border and GetMinimumWidgetSize), to avoid
+  // subtle sizing changes. The non-native theme can basically draw at any size,
+  // so we prefer to have consistent sizing information.
+  enum class NonNative { No, Always, BecauseColorMismatch };
+  static bool IsWidgetAlwaysNonNative(nsIFrame*, StyleAppearance);
+  NonNative IsWidgetNonNative(nsIFrame*, StyleAppearance);
+
+  mozilla::LayoutDeviceIntSize GetMinimumWidgetSize(
+      nsPresContext* aPresContext, nsIFrame* aFrame,
+      StyleAppearance aAppearance) override;
+
+  NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, StyleAppearance aAppearance,
+                                nsAtom* aAttribute, bool* aShouldRepaint,
+                                const nsAttrValue* aOldValue) override;
+
+  NS_IMETHOD ThemeChanged() override;
+
+  NS_IMETHOD_(bool)
+  ThemeSupportsWidget(nsPresContext* aPresContext, nsIFrame* aFrame,
+                      StyleAppearance aAppearance) override;
+
+  NS_IMETHOD_(bool) WidgetIsContainer(StyleAppearance aAppearance) override;
+
+  bool ThemeDrawsFocusForWidget(nsIFrame*, StyleAppearance) override;
+
+  bool ThemeNeedsComboboxDropmarker() override;
+  Transparency GetWidgetTransparency(nsIFrame*, StyleAppearance) override;
+
+  nsNativeThemeGTK();
+
+ protected:
+  virtual ~nsNativeThemeGTK();
+
+ private:
+  GtkTextDirection GetTextDirection(nsIFrame* aFrame);
+  gint GetTabMarginPixels(nsIFrame* aFrame);
+  bool GetGtkWidgetAndState(StyleAppearance aAppearance, nsIFrame* aFrame,
+                            WidgetNodeType& aGtkWidgetType,
+                            GtkWidgetState* aState, gint* aWidgetFlags);
+  mozilla::CSSIntMargin GetExtraSizeForWidget(nsIFrame*, StyleAppearance);
+  bool IsWidgetVisible(StyleAppearance aAppearance);
+
+  void RefreshWidgetWindow(nsIFrame* aFrame);
+  WidgetNodeType NativeThemeToGtkTheme(StyleAppearance aAppearance,
+                                       nsIFrame* aFrame);
+
+  uint8_t mDisabledWidgetTypes
+      [(static_cast<size_t>(mozilla::StyleAppearance::Count) + 7) / 8];
+  uint8_t
+      mSafeWidgetStates[static_cast<size_t>(mozilla::StyleAppearance::Count) *
+                        4];  // 32 bits per widget
+  static const char* sDisabledEngines[];
+
+  // Because moz_gtk_get_widget_border can be slow, we cache its results
+  // by widget type.  Each bit in mBorderCacheValid says whether the
+  // corresponding entry in mBorderCache is valid.
+  mozilla::CSSIntMargin GetCachedWidgetBorder(nsIFrame* aFrame,
+                                              StyleAppearance aAppearance,
+                                              GtkTextDirection aDirection);
+  uint8_t mBorderCacheValid[(MOZ_GTK_WIDGET_NODE_COUNT + 7) / 8];
+  mozilla::CSSIntMargin mBorderCache[MOZ_GTK_WIDGET_NODE_COUNT];
+};
+
+#endif
diff --git a/widget/gtk/nsPrintDialogGTK.cpp b/widget/gtk/nsPrintDialogGTK.cpp
new file mode 100644
index 0000000000..3885a94c24
--- /dev/null
+++ b/widget/gtk/nsPrintDialogGTK.cpp
@@ -0,0 +1,621 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <gtk/gtk.h>
+#include <gtk/gtkunixprint.h>
+#include <stdlib.h>
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/Services.h"
+
+#include "MozContainer.h"
+#include "nsIPrintSettings.h"
+#include "nsIWidget.h"
+#include "nsPrintDialogGTK.h"
+#include "nsPrintSettingsGTK.h"
+#include "nsString.h"
+#include "nsReadableUtils.h"
+#include "nsIStringBundle.h"
+#include "nsIPrintSettingsService.h"
+#include "nsPIDOMWindow.h"
+#include "nsPrintfCString.h"
+#include "nsIGIOService.h"
+#include "nsServiceManagerUtils.h"
+#include "WidgetUtils.h"
+#include "WidgetUtilsGtk.h"
+#include "nsIObserverService.h"
+
+// for gdk_x11_window_get_xid
+#include <gdk/gdk.h>
+#ifdef MOZ_X11
+#  include <gdk/gdkx.h>
+#endif
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <gio/gunixfdlist.h>
+
+// for dlsym
+#include <dlfcn.h>
+#include "MainThreadUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+static const char header_footer_tags[][4] = {"", "&T", "&U", "&D", "&P", "&PT"};
+
+#define CUSTOM_VALUE_INDEX gint(ArrayLength(header_footer_tags))
+
+static GtkWindow* get_gtk_window_for_nsiwidget(nsIWidget* widget) {
+  return GTK_WINDOW(widget->GetNativeData(NS_NATIVE_SHELLWIDGET));
+}
+
+static void ShowCustomDialog(GtkComboBox* changed_box, gpointer user_data) {
+  if (gtk_combo_box_get_active(changed_box) != CUSTOM_VALUE_INDEX) {
+    g_object_set_data(G_OBJECT(changed_box), "previous-active",
+                      GINT_TO_POINTER(gtk_combo_box_get_active(changed_box)));
+    return;
+  }
+
+  GtkWindow* printDialog = GTK_WINDOW(user_data);
+  nsCOMPtr<nsIStringBundleService> bundleSvc =
+      do_GetService(NS_STRINGBUNDLE_CONTRACTID);
+
+  nsCOMPtr<nsIStringBundle> printBundle;
+  bundleSvc->CreateBundle("chrome://global/locale/printdialog.properties",
+                          getter_AddRefs(printBundle));
+  nsAutoString intlString;
+
+  printBundle->GetStringFromName("headerFooterCustom", intlString);
+  GtkWidget* prompt_dialog = gtk_dialog_new_with_buttons(
+      NS_ConvertUTF16toUTF8(intlString).get(), printDialog,
+      (GtkDialogFlags)(GTK_DIALOG_MODAL), GTK_STOCK_CANCEL, GTK_RESPONSE_REJECT,
+      GTK_STOCK_OK, GTK_RESPONSE_ACCEPT, nullptr);
+  gtk_dialog_set_default_response(GTK_DIALOG(prompt_dialog),
+                                  GTK_RESPONSE_ACCEPT);
+  gtk_dialog_set_alternative_button_order(
+      GTK_DIALOG(prompt_dialog), GTK_RESPONSE_ACCEPT, GTK_RESPONSE_REJECT, -1);
+
+  printBundle->GetStringFromName("customHeaderFooterPrompt", intlString);
+  GtkWidget* custom_label =
+      gtk_label_new(NS_ConvertUTF16toUTF8(intlString).get());
+  GtkWidget* custom_entry = gtk_entry_new();
+  GtkWidget* question_icon =
+      gtk_image_new_from_stock(GTK_STOCK_DIALOG_QUESTION, GTK_ICON_SIZE_DIALOG);
+
+  // To be convenient, prefill the textbox with the existing value, if any, and
+  // select it all so they can easily both edit it and type in a new one.
+  const char* current_text =
+      (const char*)g_object_get_data(G_OBJECT(changed_box), "custom-text");
+  if (current_text) {
+    gtk_entry_set_text(GTK_ENTRY(custom_entry), current_text);
+    gtk_editable_select_region(GTK_EDITABLE(custom_entry), 0, -1);
+  }
+  gtk_entry_set_activates_default(GTK_ENTRY(custom_entry), TRUE);
+
+  GtkWidget* custom_vbox = gtk_vbox_new(TRUE, 2);
+  gtk_box_pack_start(GTK_BOX(custom_vbox), custom_label, FALSE, FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(custom_vbox), custom_entry, FALSE, FALSE,
+                     5);  // Make entry 5px underneath label
+  GtkWidget* custom_hbox = gtk_hbox_new(FALSE, 2);
+  gtk_box_pack_start(GTK_BOX(custom_hbox), question_icon, FALSE, FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(custom_hbox), custom_vbox, FALSE, FALSE,
+                     10);  // Make question icon 10px away from content
+  gtk_container_set_border_width(GTK_CONTAINER(custom_hbox), 2);
+  gtk_widget_show_all(custom_hbox);
+
+  gtk_box_pack_start(
+      GTK_BOX(gtk_dialog_get_content_area(GTK_DIALOG(prompt_dialog))),
+      custom_hbox, FALSE, FALSE, 0);
+  gint diag_response = gtk_dialog_run(GTK_DIALOG(prompt_dialog));
+
+  if (diag_response == GTK_RESPONSE_ACCEPT) {
+    const gchar* response_text = gtk_entry_get_text(GTK_ENTRY(custom_entry));
+    g_object_set_data_full(G_OBJECT(changed_box), "custom-text",
+                           strdup(response_text), (GDestroyNotify)free);
+    g_object_set_data(G_OBJECT(changed_box), "previous-active",
+                      GINT_TO_POINTER(CUSTOM_VALUE_INDEX));
+  } else {
+    // Go back to the previous index
+    gint previous_active = GPOINTER_TO_INT(
+        g_object_get_data(G_OBJECT(changed_box), "previous-active"));
+    gtk_combo_box_set_active(changed_box, previous_active);
+  }
+
+  gtk_widget_destroy(prompt_dialog);
+}
+
+class nsPrintDialogWidgetGTK {
+ public:
+  nsPrintDialogWidgetGTK(nsPIDOMWindowOuter* aParent, bool aHaveSelection,
+                         nsIPrintSettings* aPrintSettings);
+  ~nsPrintDialogWidgetGTK() { gtk_widget_destroy(dialog); }
+  NS_ConvertUTF16toUTF8 GetUTF8FromBundle(const char* aKey);
+  gint Run();
+
+  nsresult ImportSettings(nsIPrintSettings* aNSSettings);
+  nsresult ExportSettings(nsIPrintSettings* aNSSettings);
+
+ private:
+  GtkWidget* dialog;
+  GtkWidget* shrink_to_fit_toggle;
+  GtkWidget* print_bg_colors_toggle;
+  GtkWidget* print_bg_images_toggle;
+  GtkWidget* selection_only_toggle;
+  GtkWidget* header_dropdown[3];  // {left, center, right}
+  GtkWidget* footer_dropdown[3];
+
+  nsCOMPtr<nsIStringBundle> printBundle;
+
+  bool useNativeSelection;
+
+  GtkWidget* ConstructHeaderFooterDropdown(const char16_t* currentString);
+  const char* OptionWidgetToString(GtkWidget* dropdown);
+
+  /* Code to copy between GTK and NS print settings structures.
+   * In the following,
+   *   "Import" means to copy from NS to GTK
+   *   "Export" means to copy from GTK to NS
+   */
+  void ExportHeaderFooter(nsIPrintSettings* aNS);
+};
+
+nsPrintDialogWidgetGTK::nsPrintDialogWidgetGTK(nsPIDOMWindowOuter* aParent,
+                                               bool aHaveSelection,
+                                               nsIPrintSettings* aSettings) {
+  nsCOMPtr<nsIWidget> widget = WidgetUtils::DOMWindowToWidget(aParent);
+  NS_ASSERTION(widget, "Need a widget for dialog to be modal.");
+  GtkWindow* gtkParent = get_gtk_window_for_nsiwidget(widget);
+  NS_ASSERTION(gtkParent, "Need a GTK window for dialog to be modal.");
+
+  nsCOMPtr<nsIStringBundleService> bundleSvc =
+      do_GetService(NS_STRINGBUNDLE_CONTRACTID);
+  bundleSvc->CreateBundle("chrome://global/locale/printdialog.properties",
+                          getter_AddRefs(printBundle));
+
+  dialog = gtk_print_unix_dialog_new(GetUTF8FromBundle("printTitleGTK").get(),
+                                     gtkParent);
+
+  gtk_print_unix_dialog_set_manual_capabilities(
+      GTK_PRINT_UNIX_DIALOG(dialog),
+      GtkPrintCapabilities(
+          GTK_PRINT_CAPABILITY_COPIES | GTK_PRINT_CAPABILITY_COLLATE |
+          GTK_PRINT_CAPABILITY_REVERSE | GTK_PRINT_CAPABILITY_SCALE |
+          GTK_PRINT_CAPABILITY_GENERATE_PDF));
+
+  // The vast majority of magic numbers in this widget construction are padding.
+  // e.g. for the set_border_width below, 12px matches that of just about every
+  // other window.
+  GtkWidget* custom_options_tab = gtk_vbox_new(FALSE, 0);
+  gtk_container_set_border_width(GTK_CONTAINER(custom_options_tab), 12);
+  GtkWidget* tab_label =
+      gtk_label_new(GetUTF8FromBundle("optionsTabLabelGTK").get());
+
+  // Check buttons for shrink-to-fit and print selection
+  GtkWidget* check_buttons_container = gtk_vbox_new(TRUE, 2);
+  shrink_to_fit_toggle = gtk_check_button_new_with_mnemonic(
+      GetUTF8FromBundle("shrinkToFit").get());
+  gtk_box_pack_start(GTK_BOX(check_buttons_container), shrink_to_fit_toggle,
+                     FALSE, FALSE, 0);
+
+  // GTK+2.18 and above allow us to add a "Selection" option to the main
+  // settings screen, rather than adding an option on a custom tab like we must
+  // do on older versions.
+  if (gtk_major_version > 2 ||
+      (gtk_major_version == 2 && gtk_minor_version >= 18)) {
+    useNativeSelection = true;
+    g_object_set(dialog, "support-selection", TRUE, "has-selection",
+                 aHaveSelection, "embed-page-setup", TRUE, nullptr);
+  } else {
+    useNativeSelection = false;
+    selection_only_toggle = gtk_check_button_new_with_mnemonic(
+        GetUTF8FromBundle("selectionOnly").get());
+    gtk_widget_set_sensitive(selection_only_toggle, aHaveSelection);
+    gtk_box_pack_start(GTK_BOX(check_buttons_container), selection_only_toggle,
+                       FALSE, FALSE, 0);
+  }
+
+  // Check buttons for printing background
+  GtkWidget* appearance_buttons_container = gtk_vbox_new(TRUE, 2);
+  print_bg_colors_toggle = gtk_check_button_new_with_mnemonic(
+      GetUTF8FromBundle("printBGColors").get());
+  print_bg_images_toggle = gtk_check_button_new_with_mnemonic(
+      GetUTF8FromBundle("printBGImages").get());
+  gtk_box_pack_start(GTK_BOX(appearance_buttons_container),
+                     print_bg_colors_toggle, FALSE, FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(appearance_buttons_container),
+                     print_bg_images_toggle, FALSE, FALSE, 0);
+
+  // "Appearance" options label, bold and center-aligned
+  GtkWidget* appearance_label = gtk_label_new(nullptr);
+  char* pangoMarkup = g_markup_printf_escaped(
+      "<b>%s</b>", GetUTF8FromBundle("printBGOptions").get());
+  gtk_label_set_markup(GTK_LABEL(appearance_label), pangoMarkup);
+  g_free(pangoMarkup);
+  gtk_misc_set_alignment(GTK_MISC(appearance_label), 0, 0);
+
+  GtkWidget* appearance_container = gtk_alignment_new(0, 0, 0, 0);
+  gtk_alignment_set_padding(GTK_ALIGNMENT(appearance_container), 8, 0, 12, 0);
+  gtk_container_add(GTK_CONTAINER(appearance_container),
+                    appearance_buttons_container);
+
+  GtkWidget* appearance_vertical_squasher = gtk_vbox_new(FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(appearance_vertical_squasher), appearance_label,
+                     FALSE, FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(appearance_vertical_squasher),
+                     appearance_container, FALSE, FALSE, 0);
+
+  // "Header & Footer" options label, bold and center-aligned
+  GtkWidget* header_footer_label = gtk_label_new(nullptr);
+  pangoMarkup = g_markup_printf_escaped(
+      "<b>%s</b>", GetUTF8FromBundle("headerFooter").get());
+  gtk_label_set_markup(GTK_LABEL(header_footer_label), pangoMarkup);
+  g_free(pangoMarkup);
+  gtk_misc_set_alignment(GTK_MISC(header_footer_label), 0, 0);
+
+  GtkWidget* header_footer_container = gtk_alignment_new(0, 0, 0, 0);
+  gtk_alignment_set_padding(GTK_ALIGNMENT(header_footer_container), 8, 0, 12,
+                            0);
+
+  // --- Table for making the header and footer options ---
+  GtkWidget* header_footer_table = gtk_table_new(3, 3, FALSE);  // 3x3 table
+  nsString header_footer_str[3];
+
+  aSettings->GetHeaderStrLeft(header_footer_str[0]);
+  aSettings->GetHeaderStrCenter(header_footer_str[1]);
+  aSettings->GetHeaderStrRight(header_footer_str[2]);
+
+  for (unsigned int i = 0; i < ArrayLength(header_dropdown); i++) {
+    header_dropdown[i] =
+        ConstructHeaderFooterDropdown(header_footer_str[i].get());
+    // Those 4 magic numbers in the middle provide the position in the table.
+    // The last two numbers mean 2 px padding on every side.
+    gtk_table_attach(GTK_TABLE(header_footer_table), header_dropdown[i], i,
+                     (i + 1), 0, 1, (GtkAttachOptions)0, (GtkAttachOptions)0, 2,
+                     2);
+  }
+
+  const char labelKeys[][7] = {"left", "center", "right"};
+  for (unsigned int i = 0; i < ArrayLength(labelKeys); i++) {
+    gtk_table_attach(GTK_TABLE(header_footer_table),
+                     gtk_label_new(GetUTF8FromBundle(labelKeys[i]).get()), i,
+                     (i + 1), 1, 2, (GtkAttachOptions)0, (GtkAttachOptions)0, 2,
+                     2);
+  }
+
+  aSettings->GetFooterStrLeft(header_footer_str[0]);
+  aSettings->GetFooterStrCenter(header_footer_str[1]);
+  aSettings->GetFooterStrRight(header_footer_str[2]);
+
+  for (unsigned int i = 0; i < ArrayLength(footer_dropdown); i++) {
+    footer_dropdown[i] =
+        ConstructHeaderFooterDropdown(header_footer_str[i].get());
+    gtk_table_attach(GTK_TABLE(header_footer_table), footer_dropdown[i], i,
+                     (i + 1), 2, 3, (GtkAttachOptions)0, (GtkAttachOptions)0, 2,
+                     2);
+  }
+  // ---
+
+  gtk_container_add(GTK_CONTAINER(header_footer_container),
+                    header_footer_table);
+
+  GtkWidget* header_footer_vertical_squasher = gtk_vbox_new(FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(header_footer_vertical_squasher),
+                     header_footer_label, FALSE, FALSE, 0);
+  gtk_box_pack_start(GTK_BOX(header_footer_vertical_squasher),
+                     header_footer_container, FALSE, FALSE, 0);
+
+  // Construction of everything
+  gtk_box_pack_start(GTK_BOX(custom_options_tab), check_buttons_container,
+                     FALSE, FALSE, 10);  // 10px padding
+  gtk_box_pack_start(GTK_BOX(custom_options_tab), appearance_vertical_squasher,
+                     FALSE, FALSE, 10);
+  gtk_box_pack_start(GTK_BOX(custom_options_tab),
+                     header_footer_vertical_squasher, FALSE, FALSE, 0);
+
+  gtk_print_unix_dialog_add_custom_tab(GTK_PRINT_UNIX_DIALOG(dialog),
+                                       custom_options_tab, tab_label);
+  gtk_widget_show_all(custom_options_tab);
+}
+
+NS_ConvertUTF16toUTF8 nsPrintDialogWidgetGTK::GetUTF8FromBundle(
+    const char* aKey) {
+  nsAutoString intlString;
+  printBundle->GetStringFromName(aKey, intlString);
+  return NS_ConvertUTF16toUTF8(
+      intlString);  // Return the actual object so we don't lose reference
+}
+
+const char* nsPrintDialogWidgetGTK::OptionWidgetToString(GtkWidget* dropdown) {
+  gint index = gtk_combo_box_get_active(GTK_COMBO_BOX(dropdown));
+
+  NS_ASSERTION(index <= CUSTOM_VALUE_INDEX,
+               "Index of dropdown is higher than expected!");
+
+  if (index == CUSTOM_VALUE_INDEX)
+    return (const char*)g_object_get_data(G_OBJECT(dropdown), "custom-text");
+  return header_footer_tags[index];
+}
+
+gint nsPrintDialogWidgetGTK::Run() {
+  const gint response = gtk_dialog_run(GTK_DIALOG(dialog));
+  gtk_widget_hide(dialog);
+  return response;
+}
+
+void nsPrintDialogWidgetGTK::ExportHeaderFooter(nsIPrintSettings* aNS) {
+  const char* header_footer_str;
+  header_footer_str = OptionWidgetToString(header_dropdown[0]);
+  aNS->SetHeaderStrLeft(NS_ConvertUTF8toUTF16(header_footer_str));
+
+  header_footer_str = OptionWidgetToString(header_dropdown[1]);
+  aNS->SetHeaderStrCenter(NS_ConvertUTF8toUTF16(header_footer_str));
+
+  header_footer_str = OptionWidgetToString(header_dropdown[2]);
+  aNS->SetHeaderStrRight(NS_ConvertUTF8toUTF16(header_footer_str));
+
+  header_footer_str = OptionWidgetToString(footer_dropdown[0]);
+  aNS->SetFooterStrLeft(NS_ConvertUTF8toUTF16(header_footer_str));
+
+  header_footer_str = OptionWidgetToString(footer_dropdown[1]);
+  aNS->SetFooterStrCenter(NS_ConvertUTF8toUTF16(header_footer_str));
+
+  header_footer_str = OptionWidgetToString(footer_dropdown[2]);
+  aNS->SetFooterStrRight(NS_ConvertUTF8toUTF16(header_footer_str));
+}
+
+nsresult nsPrintDialogWidgetGTK::ImportSettings(nsIPrintSettings* aNSSettings) {
+  MOZ_ASSERT(aNSSettings, "aSettings must not be null");
+  NS_ENSURE_TRUE(aNSSettings, NS_ERROR_FAILURE);
+
+  nsCOMPtr<nsPrintSettingsGTK> aNSSettingsGTK(do_QueryInterface(aNSSettings));
+  if (!aNSSettingsGTK) return NS_ERROR_FAILURE;
+
+  GtkPrintSettings* settings = aNSSettingsGTK->GetGtkPrintSettings();
+  GtkPageSetup* setup = aNSSettingsGTK->GetGtkPageSetup();
+
+  // Set our custom fields:
+
+  bool geckoBool;
+  aNSSettings->GetShrinkToFit(&geckoBool);
+  gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(shrink_to_fit_toggle),
+                               geckoBool);
+
+  gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(print_bg_colors_toggle),
+                               aNSSettings->GetPrintBGColors());
+
+  gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(print_bg_images_toggle),
+                               aNSSettings->GetPrintBGImages());
+
+  // Temporarily set the pages-per-sheet on the GtkPrintSettings:
+  int32_t pagesPerSide;
+  aNSSettings->GetNumPagesPerSheet(&pagesPerSide);
+  gtk_print_settings_set_number_up(settings, pagesPerSide);
+
+  gtk_print_unix_dialog_set_settings(GTK_PRINT_UNIX_DIALOG(dialog), settings);
+  gtk_print_unix_dialog_set_page_setup(GTK_PRINT_UNIX_DIALOG(dialog), setup);
+
+  return NS_OK;
+}
+
+nsresult nsPrintDialogWidgetGTK::ExportSettings(nsIPrintSettings* aNSSettings) {
+  MOZ_ASSERT(aNSSettings, "aSettings must not be null");
+  NS_ENSURE_TRUE(aNSSettings, NS_ERROR_FAILURE);
+
+  GtkPrintSettings* settings =
+      gtk_print_unix_dialog_get_settings(GTK_PRINT_UNIX_DIALOG(dialog));
+  GtkPageSetup* setup =
+      gtk_print_unix_dialog_get_page_setup(GTK_PRINT_UNIX_DIALOG(dialog));
+  GtkPrinter* printer =
+      gtk_print_unix_dialog_get_selected_printer(GTK_PRINT_UNIX_DIALOG(dialog));
+  if (settings && setup && printer) {
+    ExportHeaderFooter(aNSSettings);
+
+    aNSSettings->SetOutputFormat(nsIPrintSettings::kOutputFormatNative);
+
+    // Print-to-file is true by default. This must be turned off or else
+    // printing won't occur! (We manually copy the spool file when this flag is
+    // set, because we love our embedders) Even if it is print-to-file in GTK's
+    // case, GTK does The Right Thing when we send the job.
+    aNSSettings->SetOutputDestination(
+        nsIPrintSettings::kOutputDestinationPrinter);
+
+    aNSSettings->SetShrinkToFit(
+        gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(shrink_to_fit_toggle)));
+
+    aNSSettings->SetPrintBGColors(gtk_toggle_button_get_active(
+        GTK_TOGGLE_BUTTON(print_bg_colors_toggle)));
+    aNSSettings->SetPrintBGImages(gtk_toggle_button_get_active(
+        GTK_TOGGLE_BUTTON(print_bg_images_toggle)));
+
+    // Move any pages-per-sheet value from the GtkPrintSettings to our
+    // nsIPrintSettings. (We handle pages-per-sheet internally and don't want
+    // the native Linux printing code to doubly apply that value!)
+    int32_t pagesPerSide = gtk_print_settings_get_number_up(settings);
+    gtk_print_settings_set_number_up(settings, 1);
+    aNSSettings->SetNumPagesPerSheet(pagesPerSide);
+
+    // Try to save native settings in the session object
+    nsCOMPtr<nsPrintSettingsGTK> aNSSettingsGTK(do_QueryInterface(aNSSettings));
+    if (aNSSettingsGTK) {
+      aNSSettingsGTK->SetGtkPrintSettings(settings);
+      aNSSettingsGTK->SetGtkPageSetup(setup);
+      aNSSettingsGTK->SetGtkPrinter(printer);
+      bool printSelectionOnly;
+      if (useNativeSelection) {
+        _GtkPrintPages pageSetting =
+            (_GtkPrintPages)gtk_print_settings_get_print_pages(settings);
+        printSelectionOnly = (pageSetting == _GTK_PRINT_PAGES_SELECTION);
+      } else {
+        printSelectionOnly = gtk_toggle_button_get_active(
+            GTK_TOGGLE_BUTTON(selection_only_toggle));
+      }
+      aNSSettingsGTK->SetPrintSelectionOnly(printSelectionOnly);
+    }
+  }
+
+  if (settings) g_object_unref(settings);
+  return NS_OK;
+}
+
+GtkWidget* nsPrintDialogWidgetGTK::ConstructHeaderFooterDropdown(
+    const char16_t* currentString) {
+  GtkWidget* dropdown = gtk_combo_box_text_new();
+  const char hf_options[][22] = {"headerFooterBlank", "headerFooterTitle",
+                                 "headerFooterURL",   "headerFooterDate",
+                                 "headerFooterPage",  "headerFooterPageTotal",
+                                 "headerFooterCustom"};
+
+  for (unsigned int i = 0; i < ArrayLength(hf_options); i++) {
+    gtk_combo_box_text_append(GTK_COMBO_BOX_TEXT(dropdown), nullptr,
+                              GetUTF8FromBundle(hf_options[i]).get());
+  }
+
+  bool shouldBeCustom = true;
+  NS_ConvertUTF16toUTF8 currentStringUTF8(currentString);
+
+  for (unsigned int i = 0; i < ArrayLength(header_footer_tags); i++) {
+    if (!strcmp(currentStringUTF8.get(), header_footer_tags[i])) {
+      gtk_combo_box_set_active(GTK_COMBO_BOX(dropdown), i);
+      g_object_set_data(G_OBJECT(dropdown), "previous-active",
+                        GINT_TO_POINTER(i));
+      shouldBeCustom = false;
+      break;
+    }
+  }
+
+  if (shouldBeCustom) {
+    gtk_combo_box_set_active(GTK_COMBO_BOX(dropdown), CUSTOM_VALUE_INDEX);
+    g_object_set_data(G_OBJECT(dropdown), "previous-active",
+                      GINT_TO_POINTER(CUSTOM_VALUE_INDEX));
+    char* custom_string = strdup(currentStringUTF8.get());
+    g_object_set_data_full(G_OBJECT(dropdown), "custom-text", custom_string,
+                           (GDestroyNotify)free);
+  }
+
+  g_signal_connect(dropdown, "changed", (GCallback)ShowCustomDialog, dialog);
+  return dropdown;
+}
+
+NS_IMPL_ISUPPORTS(nsPrintDialogServiceGTK, nsIPrintDialogService)
+
+nsPrintDialogServiceGTK::nsPrintDialogServiceGTK() = default;
+
+nsPrintDialogServiceGTK::~nsPrintDialogServiceGTK() = default;
+
+NS_IMETHODIMP
+nsPrintDialogServiceGTK::Init() { return NS_OK; }
+
+NS_IMETHODIMP
+nsPrintDialogServiceGTK::ShowPrintDialog(mozIDOMWindowProxy* aParent,
+                                         bool aHaveSelection,
+                                         nsIPrintSettings* aSettings) {
+  MOZ_ASSERT(aParent, "aParent must not be null");
+  MOZ_ASSERT(aSettings, "aSettings must not be null");
+
+  nsPrintDialogWidgetGTK printDialog(nsPIDOMWindowOuter::From(aParent),
+                                     aHaveSelection, aSettings);
+  nsresult rv = printDialog.ImportSettings(aSettings);
+
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  const gint response = printDialog.Run();
+
+  // Handle the result
+  switch (response) {
+    case GTK_RESPONSE_OK:  // Proceed
+      rv = printDialog.ExportSettings(aSettings);
+      break;
+
+    case GTK_RESPONSE_CANCEL:
+    case GTK_RESPONSE_CLOSE:
+    case GTK_RESPONSE_DELETE_EVENT:
+    case GTK_RESPONSE_NONE:
+      rv = NS_ERROR_ABORT;
+      break;
+
+    case GTK_RESPONSE_APPLY:  // Print preview
+    default:
+      NS_WARNING("Unexpected response");
+      rv = NS_ERROR_ABORT;
+  }
+  return rv;
+}
+
+NS_IMETHODIMP
+nsPrintDialogServiceGTK::ShowPageSetupDialog(mozIDOMWindowProxy* aParent,
+                                             nsIPrintSettings* aNSSettings) {
+  MOZ_ASSERT(aParent, "aParent must not be null");
+  MOZ_ASSERT(aNSSettings, "aSettings must not be null");
+  NS_ENSURE_TRUE(aNSSettings, NS_ERROR_FAILURE);
+
+  nsCOMPtr<nsIWidget> widget =
+      WidgetUtils::DOMWindowToWidget(nsPIDOMWindowOuter::From(aParent));
+  NS_ASSERTION(widget, "Need a widget for dialog to be modal.");
+  GtkWindow* gtkParent = get_gtk_window_for_nsiwidget(widget);
+  NS_ASSERTION(gtkParent, "Need a GTK window for dialog to be modal.");
+
+  nsCOMPtr<nsPrintSettingsGTK> aNSSettingsGTK(do_QueryInterface(aNSSettings));
+  if (!aNSSettingsGTK) return NS_ERROR_FAILURE;
+
+  // We need to init the prefs here because aNSSettings in its current form is a
+  // dummy in both uses of the word
+  nsCOMPtr<nsIPrintSettingsService> psService =
+      do_GetService("@mozilla.org/gfx/printsettings-service;1");
+  if (psService) {
+    nsString printName;
+    aNSSettings->GetPrinterName(printName);
+    if (printName.IsVoid()) {
+      psService->GetLastUsedPrinterName(printName);
+      aNSSettings->SetPrinterName(printName);
+    }
+    psService->InitPrintSettingsFromPrefs(aNSSettings, true,
+                                          nsIPrintSettings::kInitSaveAll);
+  }
+
+  // Frustratingly, gtk_print_run_page_setup_dialog doesn't tell us whether
+  // the user cancelled or confirmed the dialog! So to avoid needlessly
+  // refreshing the preview when Page Setup was cancelled, we compare the
+  // serializations of old and new settings; if they're the same, bail out.
+  GtkPrintSettings* gtkSettings = aNSSettingsGTK->GetGtkPrintSettings();
+  GtkPageSetup* oldPageSetup = aNSSettingsGTK->GetGtkPageSetup();
+  GKeyFile* oldKeyFile = g_key_file_new();
+  gtk_page_setup_to_key_file(oldPageSetup, oldKeyFile, nullptr);
+  gsize oldLength;
+  gchar* oldData = g_key_file_to_data(oldKeyFile, &oldLength, nullptr);
+  g_key_file_free(oldKeyFile);
+
+  GtkPageSetup* newPageSetup =
+      gtk_print_run_page_setup_dialog(gtkParent, oldPageSetup, gtkSettings);
+
+  GKeyFile* newKeyFile = g_key_file_new();
+  gtk_page_setup_to_key_file(newPageSetup, newKeyFile, nullptr);
+  gsize newLength;
+  gchar* newData = g_key_file_to_data(newKeyFile, &newLength, nullptr);
+  g_key_file_free(newKeyFile);
+
+  bool unchanged =
+      (oldLength == newLength && !memcmp(oldData, newData, oldLength));
+  g_free(oldData);
+  g_free(newData);
+  if (unchanged) {
+    g_object_unref(newPageSetup);
+    return NS_ERROR_ABORT;
+  }
+
+  aNSSettingsGTK->SetGtkPageSetup(newPageSetup);
+
+  // Now newPageSetup has a refcount of 2 (SetGtkPageSetup will addref), put it
+  // to 1 so if this gets replaced we don't leak.
+  g_object_unref(newPageSetup);
+
+  if (psService)
+    psService->MaybeSavePrintSettingsToPrefs(
+        aNSSettings, nsIPrintSettings::kInitSaveOrientation |
+                         nsIPrintSettings::kInitSavePaperSize |
+                         nsIPrintSettings::kInitSaveUnwriteableMargins);
+
+  return NS_OK;
+}
diff --git a/widget/gtk/nsPrintDialogGTK.h b/widget/gtk/nsPrintDialogGTK.h
new file mode 100644
index 0000000000..4388962858
--- /dev/null
+++ b/widget/gtk/nsPrintDialogGTK.h
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrintDialog_h__
+#define nsPrintDialog_h__
+
+#include "nsIPrintDialogService.h"
+
+class nsIPrintSettings;
+
+// Copy the print pages enum here because not all versions
+// have SELECTION, which we will use
+typedef enum {
+  _GTK_PRINT_PAGES_ALL,
+  _GTK_PRINT_PAGES_CURRENT,
+  _GTK_PRINT_PAGES_RANGES,
+  _GTK_PRINT_PAGES_SELECTION
+} _GtkPrintPages;
+
+class nsPrintDialogServiceGTK final : public nsIPrintDialogService {
+  virtual ~nsPrintDialogServiceGTK();
+
+ public:
+  nsPrintDialogServiceGTK();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIPRINTDIALOGSERVICE
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsPrintDialogServiceGTK,
+                              NS_IPRINTDIALOGSERVICE_IID)
+
+#endif
diff --git a/widget/gtk/nsPrintSettingsGTK.cpp b/widget/gtk/nsPrintSettingsGTK.cpp
new file mode 100644
index 0000000000..a101f44fcb
--- /dev/null
+++ b/widget/gtk/nsPrintSettingsGTK.cpp
@@ -0,0 +1,681 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrintSettingsGTK.h"
+#include "nsIFile.h"
+#include "nsNetUtil.h"
+#include <stdlib.h>
+#include <algorithm>
+
+// These constants are the the strings that GTK expects as key-value pairs for
+// setting CUPS duplex modes. These are not universal to all CUPS systems, which
+// is why they are local to this file.
+static constexpr gchar kCupsDuplex[] = "cups-Duplex";
+static constexpr gchar kCupsDuplexNone[] = "None";
+static constexpr gchar kCupsDuplexNoTumble[] = "DuplexNoTumble";
+static constexpr gchar kCupsDuplexTumble[] = "DuplexTumble";
+
+static GtkPaperSize* moz_gtk_paper_size_copy_to_new_custom(
+    GtkPaperSize* oldPaperSize) {
+  // We make a "custom-ified" copy of the paper size so it can be changed later.
+  return gtk_paper_size_new_custom(
+      gtk_paper_size_get_name(oldPaperSize),
+      gtk_paper_size_get_display_name(oldPaperSize),
+      gtk_paper_size_get_width(oldPaperSize, GTK_UNIT_INCH),
+      gtk_paper_size_get_height(oldPaperSize, GTK_UNIT_INCH), GTK_UNIT_INCH);
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(nsPrintSettingsGTK, nsPrintSettings,
+                            nsPrintSettingsGTK)
+
+/** ---------------------------------------------------
+ */
+nsPrintSettingsGTK::nsPrintSettingsGTK()
+    : mPageSetup(nullptr), mPrintSettings(nullptr), mGTKPrinter(nullptr) {
+  // The aim here is to set up the objects enough that silent printing works
+  // well. These will be replaced anyway if the print dialog is used.
+  mPrintSettings = gtk_print_settings_new();
+  GtkPageSetup* pageSetup = gtk_page_setup_new();
+  SetGtkPageSetup(pageSetup);
+  g_object_unref(pageSetup);
+
+  SetOutputFormat(nsIPrintSettings::kOutputFormatNative);
+}
+
+already_AddRefed<nsIPrintSettings> CreatePlatformPrintSettings(
+    const mozilla::PrintSettingsInitializer& aSettings) {
+  RefPtr<nsPrintSettings> settings = new nsPrintSettingsGTK();
+  settings->InitWithInitializer(aSettings);
+  settings->SetDefaultFileName();
+  return settings.forget();
+}
+
+/** ---------------------------------------------------
+ */
+nsPrintSettingsGTK::~nsPrintSettingsGTK() {
+  if (mPageSetup) {
+    g_object_unref(mPageSetup);
+    mPageSetup = nullptr;
+  }
+  if (mPrintSettings) {
+    g_object_unref(mPrintSettings);
+    mPrintSettings = nullptr;
+  }
+  if (mGTKPrinter) {
+    g_object_unref(mGTKPrinter);
+    mGTKPrinter = nullptr;
+  }
+}
+
+/** ---------------------------------------------------
+ */
+nsPrintSettingsGTK::nsPrintSettingsGTK(const nsPrintSettingsGTK& aPS)
+    : mPageSetup(nullptr), mPrintSettings(nullptr), mGTKPrinter(nullptr) {
+  *this = aPS;
+}
+
+/** ---------------------------------------------------
+ */
+nsPrintSettingsGTK& nsPrintSettingsGTK::operator=(
+    const nsPrintSettingsGTK& rhs) {
+  if (this == &rhs) {
+    return *this;
+  }
+
+  nsPrintSettings::operator=(rhs);
+
+  if (mPageSetup) g_object_unref(mPageSetup);
+  mPageSetup = gtk_page_setup_copy(rhs.mPageSetup);
+  // NOTE: No need to re-initialize mUnwriteableMargin here (even
+  // though mPageSetup is changing). It'll be copied correctly by
+  // nsPrintSettings::operator=.
+
+  if (mPrintSettings) g_object_unref(mPrintSettings);
+  mPrintSettings = gtk_print_settings_copy(rhs.mPrintSettings);
+
+  if (mGTKPrinter) g_object_unref(mGTKPrinter);
+
+  if (rhs.mGTKPrinter) {
+    g_object_ref(rhs.mGTKPrinter);
+  }
+  mGTKPrinter = rhs.mGTKPrinter;
+
+  return *this;
+}
+
+/** -------------------------------------------
+ */
+nsresult nsPrintSettingsGTK::_Clone(nsIPrintSettings** _retval) {
+  NS_ENSURE_ARG_POINTER(_retval);
+  *_retval = nullptr;
+
+  nsPrintSettingsGTK* newSettings = new nsPrintSettingsGTK(*this);
+  if (!newSettings) return NS_ERROR_FAILURE;
+  *_retval = newSettings;
+  NS_ADDREF(*_retval);
+  return NS_OK;
+}
+
+/** -------------------------------------------
+ */
+NS_IMETHODIMP
+nsPrintSettingsGTK::_Assign(nsIPrintSettings* aPS) {
+  nsPrintSettingsGTK* printSettingsGTK = static_cast<nsPrintSettingsGTK*>(aPS);
+  if (!printSettingsGTK) return NS_ERROR_UNEXPECTED;
+  *this = *printSettingsGTK;
+  return NS_OK;
+}
+
+/** ---------------------------------------------------
+ */
+void nsPrintSettingsGTK::SetGtkPageSetup(GtkPageSetup* aPageSetup) {
+  if (mPageSetup) g_object_unref(mPageSetup);
+
+  mPageSetup = (GtkPageSetup*)g_object_ref(aPageSetup);
+  InitUnwriteableMargin();
+
+  // If the paper size is not custom, then we make a custom copy of the
+  // GtkPaperSize, so it can be mutable. If a GtkPaperSize wasn't made as
+  // custom, its properties are immutable.
+  GtkPaperSize* paperSize = gtk_page_setup_get_paper_size(aPageSetup);
+  if (!gtk_paper_size_is_custom(paperSize)) {
+    GtkPaperSize* customPaperSize =
+        moz_gtk_paper_size_copy_to_new_custom(paperSize);
+    gtk_page_setup_set_paper_size(mPageSetup, customPaperSize);
+    gtk_paper_size_free(customPaperSize);
+  }
+  SaveNewPageSize();
+}
+
+/** ---------------------------------------------------
+ */
+void nsPrintSettingsGTK::SetGtkPrintSettings(GtkPrintSettings* aPrintSettings) {
+  if (mPrintSettings) g_object_unref(mPrintSettings);
+
+  mPrintSettings = (GtkPrintSettings*)g_object_ref(aPrintSettings);
+
+  GtkPaperSize* paperSize = gtk_print_settings_get_paper_size(aPrintSettings);
+  if (paperSize) {
+    GtkPaperSize* customPaperSize =
+        moz_gtk_paper_size_copy_to_new_custom(paperSize);
+    gtk_paper_size_free(paperSize);
+    gtk_page_setup_set_paper_size(mPageSetup, customPaperSize);
+    gtk_paper_size_free(customPaperSize);
+  } else {
+    // paperSize was null, and so we add the paper size in the GtkPageSetup to
+    // the settings.
+    SaveNewPageSize();
+  }
+}
+
+/** ---------------------------------------------------
+ */
+void nsPrintSettingsGTK::SetGtkPrinter(GtkPrinter* aPrinter) {
+  if (mGTKPrinter) g_object_unref(mGTKPrinter);
+
+  mGTKPrinter = (GtkPrinter*)g_object_ref(aPrinter);
+}
+
+NS_IMETHODIMP nsPrintSettingsGTK::GetOutputFormat(int16_t* aOutputFormat) {
+  NS_ENSURE_ARG_POINTER(aOutputFormat);
+
+  int16_t format;
+  nsresult rv = nsPrintSettings::GetOutputFormat(&format);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  if (format == nsIPrintSettings::kOutputFormatNative &&
+      GTK_IS_PRINTER(mGTKPrinter)) {
+    format = nsIPrintSettings::kOutputFormatPDF;
+  }
+
+  *aOutputFormat = format;
+  return NS_OK;
+}
+
+/**
+ * Reimplementation of nsPrintSettings functions so that we get the values
+ * from the GTK objects rather than our own variables.
+ */
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetPageRanges(const nsTArray<int32_t>& aRanges) {
+  if (aRanges.Length() % 2 != 0) {
+    return NS_ERROR_FAILURE;
+  }
+
+  gtk_print_settings_set_print_pages(
+      mPrintSettings,
+      aRanges.IsEmpty() ? GTK_PRINT_PAGES_ALL : GTK_PRINT_PAGES_RANGES);
+
+  nsTArray<GtkPageRange> ranges;
+  ranges.SetCapacity(aRanges.Length() / 2);
+  for (size_t i = 0; i < aRanges.Length(); i += 2) {
+    GtkPageRange* gtkRange = ranges.AppendElement();
+    gtkRange->start = aRanges[i] - 1;
+    gtkRange->end = aRanges[i + 1] - 1;
+  }
+
+  gtk_print_settings_set_page_ranges(mPrintSettings, ranges.Elements(),
+                                     ranges.Length());
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetPrintReversed(bool* aPrintReversed) {
+  *aPrintReversed = gtk_print_settings_get_reverse(mPrintSettings);
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetPrintReversed(bool aPrintReversed) {
+  gtk_print_settings_set_reverse(mPrintSettings, aPrintReversed);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetPrintInColor(bool* aPrintInColor) {
+  *aPrintInColor = gtk_print_settings_get_use_color(mPrintSettings);
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetPrintInColor(bool aPrintInColor) {
+  gtk_print_settings_set_use_color(mPrintSettings, aPrintInColor);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetOrientation(int32_t* aOrientation) {
+  NS_ENSURE_ARG_POINTER(aOrientation);
+
+  GtkPageOrientation gtkOrient = gtk_page_setup_get_orientation(mPageSetup);
+  switch (gtkOrient) {
+    case GTK_PAGE_ORIENTATION_LANDSCAPE:
+    case GTK_PAGE_ORIENTATION_REVERSE_LANDSCAPE:
+      *aOrientation = kLandscapeOrientation;
+      break;
+
+    case GTK_PAGE_ORIENTATION_PORTRAIT:
+    case GTK_PAGE_ORIENTATION_REVERSE_PORTRAIT:
+    default:
+      *aOrientation = kPortraitOrientation;
+  }
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetOrientation(int32_t aOrientation) {
+  GtkPageOrientation gtkOrient;
+  if (aOrientation == kLandscapeOrientation)
+    gtkOrient = GTK_PAGE_ORIENTATION_LANDSCAPE;
+  else
+    gtkOrient = GTK_PAGE_ORIENTATION_PORTRAIT;
+
+  gtk_print_settings_set_orientation(mPrintSettings, gtkOrient);
+  gtk_page_setup_set_orientation(mPageSetup, gtkOrient);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetToFileName(nsAString& aToFileName) {
+  // Get the gtk output filename
+  const char* gtk_output_uri =
+      gtk_print_settings_get(mPrintSettings, GTK_PRINT_SETTINGS_OUTPUT_URI);
+  if (!gtk_output_uri) {
+    aToFileName = mToFileName;
+    return NS_OK;
+  }
+
+  // Convert to an nsIFile
+  nsCOMPtr<nsIFile> file;
+  nsresult rv = NS_GetFileFromURLSpec(nsDependentCString(gtk_output_uri),
+                                      getter_AddRefs(file));
+  if (NS_FAILED(rv)) return rv;
+
+  // Extract the path
+  return file->GetPath(aToFileName);
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetToFileName(const nsAString& aToFileName) {
+  if (aToFileName.IsEmpty()) {
+    mToFileName.SetLength(0);
+    gtk_print_settings_set(mPrintSettings, GTK_PRINT_SETTINGS_OUTPUT_URI,
+                           nullptr);
+    return NS_OK;
+  }
+
+  gtk_print_settings_set(mPrintSettings, GTK_PRINT_SETTINGS_OUTPUT_FILE_FORMAT,
+                         "pdf");
+
+  nsCOMPtr<nsIFile> file;
+  nsresult rv = NS_NewLocalFile(aToFileName, true, getter_AddRefs(file));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Convert the nsIFile to a URL
+  nsAutoCString url;
+  rv = NS_GetURLSpecFromFile(file, url);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  gtk_print_settings_set(mPrintSettings, GTK_PRINT_SETTINGS_OUTPUT_URI,
+                         url.get());
+  mToFileName = aToFileName;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetPrinterName(nsAString& aPrinter) {
+  const char* gtkPrintName = gtk_print_settings_get_printer(mPrintSettings);
+  if (!gtkPrintName) {
+    if (GTK_IS_PRINTER(mGTKPrinter)) {
+      gtkPrintName = gtk_printer_get_name(mGTKPrinter);
+    } else {
+      // This mimics what nsPrintSettingsImpl does when we try to Get before we
+      // Set
+      aPrinter.Truncate();
+      return NS_OK;
+    }
+  }
+  CopyUTF8toUTF16(mozilla::MakeStringSpan(gtkPrintName), aPrinter);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetPrinterName(const nsAString& aPrinter) {
+  NS_ConvertUTF16toUTF8 gtkPrinter(aPrinter);
+
+  if (StringBeginsWith(gtkPrinter, "CUPS/"_ns)) {
+    // Strip off "CUPS/"; GTK might recognize the rest
+    gtkPrinter.Cut(0, strlen("CUPS/"));
+  }
+
+  // Give mPrintSettings the passed-in printer name if either...
+  // - it has no printer name stored yet
+  // - it has an existing printer name that's different from
+  //   the name passed to this function.
+  const char* oldPrinterName = gtk_print_settings_get_printer(mPrintSettings);
+  if (!oldPrinterName || !gtkPrinter.Equals(oldPrinterName)) {
+    mIsInitedFromPrinter = false;
+    mIsInitedFromPrefs = false;
+    gtk_print_settings_set_printer(mPrintSettings, gtkPrinter.get());
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetNumCopies(int32_t* aNumCopies) {
+  NS_ENSURE_ARG_POINTER(aNumCopies);
+  *aNumCopies = gtk_print_settings_get_n_copies(mPrintSettings);
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetNumCopies(int32_t aNumCopies) {
+  gtk_print_settings_set_n_copies(mPrintSettings, aNumCopies);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetScaling(double* aScaling) {
+  *aScaling = gtk_print_settings_get_scale(mPrintSettings) / 100.0;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetScaling(double aScaling) {
+  gtk_print_settings_set_scale(mPrintSettings, aScaling * 100.0);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetPaperId(nsAString& aPaperId) {
+  const gchar* name =
+      gtk_paper_size_get_name(gtk_page_setup_get_paper_size(mPageSetup));
+  CopyUTF8toUTF16(mozilla::MakeStringSpan(name), aPaperId);
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetPaperId(const nsAString& aPaperId) {
+  NS_ConvertUTF16toUTF8 gtkPaperName(aPaperId);
+
+  // Convert these Gecko names to GTK names
+  // XXX (jfkthame): is this still relevant?
+  if (gtkPaperName.EqualsIgnoreCase("letter"))
+    gtkPaperName.AssignLiteral(GTK_PAPER_NAME_LETTER);
+  else if (gtkPaperName.EqualsIgnoreCase("legal"))
+    gtkPaperName.AssignLiteral(GTK_PAPER_NAME_LEGAL);
+
+  GtkPaperSize* oldPaperSize = gtk_page_setup_get_paper_size(mPageSetup);
+  gdouble width = gtk_paper_size_get_width(oldPaperSize, GTK_UNIT_INCH);
+  gdouble height = gtk_paper_size_get_height(oldPaperSize, GTK_UNIT_INCH);
+
+  // Try to get the display name from the name so our paper size fits in the
+  // Page Setup dialog.
+  GtkPaperSize* paperSize = gtk_paper_size_new(gtkPaperName.get());
+  GtkPaperSize* customPaperSize = gtk_paper_size_new_custom(
+      gtkPaperName.get(), gtk_paper_size_get_display_name(paperSize), width,
+      height, GTK_UNIT_INCH);
+  gtk_paper_size_free(paperSize);
+
+  gtk_page_setup_set_paper_size(mPageSetup, customPaperSize);
+  gtk_paper_size_free(customPaperSize);
+  SaveNewPageSize();
+  return NS_OK;
+}
+
+GtkUnit nsPrintSettingsGTK::GetGTKUnit(int16_t aGeckoUnit) {
+  if (aGeckoUnit == kPaperSizeMillimeters)
+    return GTK_UNIT_MM;
+  else
+    return GTK_UNIT_INCH;
+}
+
+void nsPrintSettingsGTK::SaveNewPageSize() {
+  gtk_print_settings_set_paper_size(mPrintSettings,
+                                    gtk_page_setup_get_paper_size(mPageSetup));
+}
+
+void nsPrintSettingsGTK::InitUnwriteableMargin() {
+  mUnwriteableMargin.SizeTo(
+      NS_INCHES_TO_INT_TWIPS(
+          gtk_page_setup_get_top_margin(mPageSetup, GTK_UNIT_INCH)),
+      NS_INCHES_TO_INT_TWIPS(
+          gtk_page_setup_get_right_margin(mPageSetup, GTK_UNIT_INCH)),
+      NS_INCHES_TO_INT_TWIPS(
+          gtk_page_setup_get_bottom_margin(mPageSetup, GTK_UNIT_INCH)),
+      NS_INCHES_TO_INT_TWIPS(
+          gtk_page_setup_get_left_margin(mPageSetup, GTK_UNIT_INCH)));
+}
+
+/**
+ * NOTE: Need a custom set of SetUnwriteableMargin functions, because
+ * whenever we change mUnwriteableMargin, we must pass the change
+ * down to our GTKPageSetup object.  (This is needed in order for us
+ * to give the correct default values in nsPrintDialogGTK.)
+ *
+ * It's important that the following functions pass
+ * mUnwriteableMargin values rather than aUnwriteableMargin values
+ * to gtk_page_setup_set_[blank]_margin, because the two may not be
+ * the same.  (Specifically, negative values of aUnwriteableMargin
+ * are ignored by the nsPrintSettings::SetUnwriteableMargin functions.)
+ */
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetUnwriteableMarginInTwips(
+    nsIntMargin& aUnwriteableMargin) {
+  nsPrintSettings::SetUnwriteableMarginInTwips(aUnwriteableMargin);
+  gtk_page_setup_set_top_margin(
+      mPageSetup, NS_TWIPS_TO_INCHES(mUnwriteableMargin.top), GTK_UNIT_INCH);
+  gtk_page_setup_set_left_margin(
+      mPageSetup, NS_TWIPS_TO_INCHES(mUnwriteableMargin.left), GTK_UNIT_INCH);
+  gtk_page_setup_set_bottom_margin(
+      mPageSetup, NS_TWIPS_TO_INCHES(mUnwriteableMargin.bottom), GTK_UNIT_INCH);
+  gtk_page_setup_set_right_margin(
+      mPageSetup, NS_TWIPS_TO_INCHES(mUnwriteableMargin.right), GTK_UNIT_INCH);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetUnwriteableMarginTop(double aUnwriteableMarginTop) {
+  nsPrintSettings::SetUnwriteableMarginTop(aUnwriteableMarginTop);
+  gtk_page_setup_set_top_margin(
+      mPageSetup, NS_TWIPS_TO_INCHES(mUnwriteableMargin.top), GTK_UNIT_INCH);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetUnwriteableMarginLeft(double aUnwriteableMarginLeft) {
+  nsPrintSettings::SetUnwriteableMarginLeft(aUnwriteableMarginLeft);
+  gtk_page_setup_set_left_margin(
+      mPageSetup, NS_TWIPS_TO_INCHES(mUnwriteableMargin.left), GTK_UNIT_INCH);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetUnwriteableMarginBottom(
+    double aUnwriteableMarginBottom) {
+  nsPrintSettings::SetUnwriteableMarginBottom(aUnwriteableMarginBottom);
+  gtk_page_setup_set_bottom_margin(
+      mPageSetup, NS_TWIPS_TO_INCHES(mUnwriteableMargin.bottom), GTK_UNIT_INCH);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetUnwriteableMarginRight(double aUnwriteableMarginRight) {
+  nsPrintSettings::SetUnwriteableMarginRight(aUnwriteableMarginRight);
+  gtk_page_setup_set_right_margin(
+      mPageSetup, NS_TWIPS_TO_INCHES(mUnwriteableMargin.right), GTK_UNIT_INCH);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetPaperWidth(double* aPaperWidth) {
+  NS_ENSURE_ARG_POINTER(aPaperWidth);
+  GtkPaperSize* paperSize = gtk_page_setup_get_paper_size(mPageSetup);
+  *aPaperWidth =
+      gtk_paper_size_get_width(paperSize, GetGTKUnit(mPaperSizeUnit));
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetPaperWidth(double aPaperWidth) {
+  GtkPaperSize* paperSize = gtk_page_setup_get_paper_size(mPageSetup);
+  gtk_paper_size_set_size(
+      paperSize, aPaperWidth,
+      gtk_paper_size_get_height(paperSize, GetGTKUnit(mPaperSizeUnit)),
+      GetGTKUnit(mPaperSizeUnit));
+  SaveNewPageSize();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetPaperHeight(double* aPaperHeight) {
+  NS_ENSURE_ARG_POINTER(aPaperHeight);
+  GtkPaperSize* paperSize = gtk_page_setup_get_paper_size(mPageSetup);
+  *aPaperHeight =
+      gtk_paper_size_get_height(paperSize, GetGTKUnit(mPaperSizeUnit));
+  return NS_OK;
+}
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetPaperHeight(double aPaperHeight) {
+  GtkPaperSize* paperSize = gtk_page_setup_get_paper_size(mPageSetup);
+  gtk_paper_size_set_size(
+      paperSize,
+      gtk_paper_size_get_width(paperSize, GetGTKUnit(mPaperSizeUnit)),
+      aPaperHeight, GetGTKUnit(mPaperSizeUnit));
+  SaveNewPageSize();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetPaperSizeUnit(int16_t aPaperSizeUnit) {
+  // Convert units internally. e.g. they might have set the values while we're
+  // still in mm but they change to inch just afterwards, expecting that their
+  // sizes are in inches.
+  GtkPaperSize* paperSize = gtk_page_setup_get_paper_size(mPageSetup);
+  gtk_paper_size_set_size(
+      paperSize,
+      gtk_paper_size_get_width(paperSize, GetGTKUnit(mPaperSizeUnit)),
+      gtk_paper_size_get_height(paperSize, GetGTKUnit(mPaperSizeUnit)),
+      GetGTKUnit(aPaperSizeUnit));
+  SaveNewPageSize();
+
+  mPaperSizeUnit = aPaperSizeUnit;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetEffectivePageSize(double* aWidth, double* aHeight) {
+  GtkPaperSize* paperSize = gtk_page_setup_get_paper_size(mPageSetup);
+  if (mPaperSizeUnit == kPaperSizeInches) {
+    *aWidth =
+        NS_INCHES_TO_TWIPS(gtk_paper_size_get_width(paperSize, GTK_UNIT_INCH));
+    *aHeight =
+        NS_INCHES_TO_TWIPS(gtk_paper_size_get_height(paperSize, GTK_UNIT_INCH));
+  } else {
+    MOZ_ASSERT(mPaperSizeUnit == kPaperSizeMillimeters,
+               "unexpected paper size unit");
+    *aWidth = NS_MILLIMETERS_TO_TWIPS(
+        gtk_paper_size_get_width(paperSize, GTK_UNIT_MM));
+    *aHeight = NS_MILLIMETERS_TO_TWIPS(
+        gtk_paper_size_get_height(paperSize, GTK_UNIT_MM));
+  }
+  GtkPageOrientation gtkOrient = gtk_page_setup_get_orientation(mPageSetup);
+
+  if (gtkOrient == GTK_PAGE_ORIENTATION_LANDSCAPE ||
+      gtkOrient == GTK_PAGE_ORIENTATION_REVERSE_LANDSCAPE) {
+    double temp = *aWidth;
+    *aWidth = *aHeight;
+    *aHeight = temp;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetPageRanges(nsTArray<int32_t>& aPages) {
+  GtkPrintPages gtkRange = gtk_print_settings_get_print_pages(mPrintSettings);
+  if (gtkRange != GTK_PRINT_PAGES_RANGES) {
+    aPages.Clear();
+    return NS_OK;
+  }
+
+  gint ctRanges;
+  GtkPageRange* lstRanges =
+      gtk_print_settings_get_page_ranges(mPrintSettings, &ctRanges);
+
+  aPages.Clear();
+
+  for (gint i = 0; i < ctRanges; i++) {
+    aPages.AppendElement(lstRanges[i].start + 1);
+    aPages.AppendElement(lstRanges[i].end + 1);
+  }
+
+  g_free(lstRanges);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetResolution(int32_t* aResolution) {
+  *aResolution = gtk_print_settings_get_resolution(mPrintSettings);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetResolution(int32_t aResolution) {
+  gtk_print_settings_set_resolution(mPrintSettings, aResolution);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::GetDuplex(int32_t* aDuplex) {
+  NS_ENSURE_ARG_POINTER(aDuplex);
+
+  // Default to DuplexNone.
+  *aDuplex = kDuplexNone;
+
+  if (!gtk_print_settings_has_key(mPrintSettings, GTK_PRINT_SETTINGS_DUPLEX)) {
+    return NS_OK;
+  }
+
+  switch (gtk_print_settings_get_duplex(mPrintSettings)) {
+    case GTK_PRINT_DUPLEX_SIMPLEX:
+      *aDuplex = kDuplexNone;
+      break;
+    case GTK_PRINT_DUPLEX_HORIZONTAL:
+      *aDuplex = kDuplexFlipOnLongEdge;
+      break;
+    case GTK_PRINT_DUPLEX_VERTICAL:
+      *aDuplex = kDuplexFlipOnShortEdge;
+      break;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsGTK::SetDuplex(int32_t aDuplex) {
+  uint32_t duplex = static_cast<uint32_t>(aDuplex);
+  MOZ_ASSERT(duplex <= kDuplexFlipOnShortEdge,
+             "value is out of bounds for duplex enum");
+
+  // We want to set the GTK CUPS Duplex setting in addition to calling
+  // gtk_print_settings_set_duplex(). Some systems may look for one, or the
+  // other, so it is best to set them both consistently.
+  switch (duplex) {
+    case kDuplexNone:
+      gtk_print_settings_set(mPrintSettings, kCupsDuplex, kCupsDuplexNone);
+      gtk_print_settings_set_duplex(mPrintSettings, GTK_PRINT_DUPLEX_SIMPLEX);
+      break;
+    case kDuplexFlipOnLongEdge:
+      gtk_print_settings_set(mPrintSettings, kCupsDuplex, kCupsDuplexNoTumble);
+      gtk_print_settings_set_duplex(mPrintSettings,
+                                    GTK_PRINT_DUPLEX_HORIZONTAL);
+      break;
+    case kDuplexFlipOnShortEdge:
+      gtk_print_settings_set(mPrintSettings, kCupsDuplex, kCupsDuplexTumble);
+      gtk_print_settings_set_duplex(mPrintSettings, GTK_PRINT_DUPLEX_VERTICAL);
+      break;
+  }
+
+  return NS_OK;
+}
diff --git a/widget/gtk/nsPrintSettingsGTK.h b/widget/gtk/nsPrintSettingsGTK.h
new file mode 100644
index 0000000000..c2d97a6208
--- /dev/null
+++ b/widget/gtk/nsPrintSettingsGTK.h
@@ -0,0 +1,147 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrintSettingsGTK_h_
+#define nsPrintSettingsGTK_h_
+
+#include "nsPrintSettingsImpl.h"
+
+extern "C" {
+#include <gtk/gtk.h>
+#include <gtk/gtkunixprint.h>
+}
+
+#define NS_PRINTSETTINGSGTK_IID                      \
+  {                                                  \
+    0x758df520, 0xc7c3, 0x11dc, {                    \
+      0x95, 0xff, 0x08, 0x00, 0x20, 0x0c, 0x9a, 0x66 \
+    }                                                \
+  }
+
+//*****************************************************************************
+//***    nsPrintSettingsGTK
+//*****************************************************************************
+
+class nsPrintSettingsGTK : public nsPrintSettings {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_PRINTSETTINGSGTK_IID)
+
+  nsPrintSettingsGTK();
+  explicit nsPrintSettingsGTK(const PrintSettingsInitializer& aSettings);
+
+  static nsPrintSettingsGTK* From(nsIPrintSettings* aPrintSettings) {
+    return static_cast<nsPrintSettingsGTK*>(aPrintSettings);
+  }
+
+  // We're overriding these methods because we want to read/write with GTK
+  // objects, not local variables. This allows a simpler settings implementation
+  // between Gecko and GTK.
+
+  GtkPageSetup* GetGtkPageSetup() { return mPageSetup; };
+  void SetGtkPageSetup(GtkPageSetup* aPageSetup);
+
+  GtkPrintSettings* GetGtkPrintSettings() { return mPrintSettings; };
+  void SetGtkPrintSettings(GtkPrintSettings* aPrintSettings);
+
+  GtkPrinter* GetGtkPrinter() { return mGTKPrinter; };
+  void SetGtkPrinter(GtkPrinter* aPrinter);
+
+  // Reversed, color, orientation and file name are all stored in the
+  // GtkPrintSettings. Orientation is also stored in the GtkPageSetup and its
+  // setting takes priority when getting the orientation.
+  NS_IMETHOD GetPrintReversed(bool* aPrintReversed) override;
+  NS_IMETHOD SetPrintReversed(bool aPrintReversed) override;
+
+  NS_IMETHOD GetPrintInColor(bool* aPrintInColor) override;
+  NS_IMETHOD SetPrintInColor(bool aPrintInColor) override;
+
+  NS_IMETHOD GetOrientation(int32_t* aOrientation) override;
+  NS_IMETHOD SetOrientation(int32_t aOrientation) override;
+
+  NS_IMETHOD GetToFileName(nsAString& aToFileName) override;
+  NS_IMETHOD SetToFileName(const nsAString& aToFileName) override;
+
+  // Gets/Sets the printer name in the GtkPrintSettings. If no printer name is
+  // specified there, you will get back the name of the current internal
+  // GtkPrinter.
+  NS_IMETHOD GetPrinterName(nsAString& Printer) override;
+  NS_IMETHOD SetPrinterName(const nsAString& aPrinter) override;
+
+  // Number of copies is stored/gotten from the GtkPrintSettings.
+  NS_IMETHOD GetNumCopies(int32_t* aNumCopies) override;
+  NS_IMETHOD SetNumCopies(int32_t aNumCopies) override;
+
+  NS_IMETHOD GetScaling(double* aScaling) override;
+  NS_IMETHOD SetScaling(double aScaling) override;
+
+  // A name recognised by GTK is strongly advised here, as this is used to
+  // create a GtkPaperSize.
+  NS_IMETHOD GetPaperId(nsAString& aPaperId) override;
+  NS_IMETHOD SetPaperId(const nsAString& aPaperId) override;
+
+  NS_IMETHOD SetUnwriteableMarginInTwips(
+      nsIntMargin& aUnwriteableMargin) override;
+  NS_IMETHOD SetUnwriteableMarginTop(double aUnwriteableMarginTop) override;
+  NS_IMETHOD SetUnwriteableMarginLeft(double aUnwriteableMarginLeft) override;
+  NS_IMETHOD SetUnwriteableMarginBottom(
+      double aUnwriteableMarginBottom) override;
+  NS_IMETHOD SetUnwriteableMarginRight(double aUnwriteableMarginRight) override;
+
+  NS_IMETHOD GetPaperWidth(double* aPaperWidth) override;
+  NS_IMETHOD SetPaperWidth(double aPaperWidth) override;
+
+  NS_IMETHOD GetPaperHeight(double* aPaperHeight) override;
+  NS_IMETHOD SetPaperHeight(double aPaperHeight) override;
+
+  NS_IMETHOD SetPaperSizeUnit(int16_t aPaperSizeUnit) override;
+
+  NS_IMETHOD GetEffectivePageSize(double* aWidth, double* aHeight) override;
+
+  NS_IMETHOD SetPageRanges(const nsTArray<int32_t>&) override;
+  NS_IMETHOD GetPageRanges(nsTArray<int32_t>&) override;
+
+  NS_IMETHOD GetResolution(int32_t* aResolution) override;
+  NS_IMETHOD SetResolution(int32_t aResolution) override;
+
+  NS_IMETHOD GetDuplex(int32_t* aDuplex) override;
+  NS_IMETHOD SetDuplex(int32_t aDuplex) override;
+
+  NS_IMETHOD GetOutputFormat(int16_t* aOutputFormat) override;
+
+ protected:
+  virtual ~nsPrintSettingsGTK();
+
+  nsPrintSettingsGTK(const nsPrintSettingsGTK& src);
+  nsPrintSettingsGTK& operator=(const nsPrintSettingsGTK& rhs);
+
+  virtual nsresult _Clone(nsIPrintSettings** _retval) override;
+  virtual nsresult _Assign(nsIPrintSettings* aPS) override;
+
+  GtkUnit GetGTKUnit(int16_t aGeckoUnit);
+  void SaveNewPageSize();
+
+  /**
+   * Re-initialize mUnwriteableMargin with values from mPageSetup.
+   * Should be called whenever mPageSetup is initialized or overwritten.
+   */
+  void InitUnwriteableMargin();
+
+  /**
+   * On construction:
+   * - mPrintSettings and mPageSetup are just new objects with defaults
+   *   determined by GTK.
+   * - mGTKPrinter is nullptr!!! Remember to be careful when accessing this
+   *   property.
+   */
+  GtkPageSetup* mPageSetup;
+  GtkPrintSettings* mPrintSettings;
+  GtkPrinter* mGTKPrinter;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsPrintSettingsGTK, NS_PRINTSETTINGSGTK_IID)
+
+#endif  // nsPrintSettingsGTK_h_
diff --git a/widget/gtk/nsPrintSettingsServiceGTK.cpp b/widget/gtk/nsPrintSettingsServiceGTK.cpp
new file mode 100644
index 0000000000..9d0dfc9379
--- /dev/null
+++ b/widget/gtk/nsPrintSettingsServiceGTK.cpp
@@ -0,0 +1,80 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrintSettingsServiceGTK.h"
+
+#include "mozilla/embedding/PPrintingTypes.h"
+#include "nsPrintSettingsGTK.h"
+
+using namespace mozilla::embedding;
+
+static void serialize_gtk_printsettings_to_printdata(const gchar* key,
+                                                     const gchar* value,
+                                                     gpointer aData) {
+  PrintData* data = (PrintData*)aData;
+  CStringKeyValue pair;
+  pair.key() = key;
+  pair.value() = value;
+  data->GTKPrintSettings().AppendElement(pair);
+}
+
+NS_IMETHODIMP
+nsPrintSettingsServiceGTK::SerializeToPrintData(nsIPrintSettings* aSettings,
+                                                PrintData* data) {
+  nsresult rv = nsPrintSettingsService::SerializeToPrintData(aSettings, data);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsPrintSettingsGTK> settingsGTK(do_QueryInterface(aSettings));
+  NS_ENSURE_STATE(settingsGTK);
+
+  GtkPrintSettings* gtkPrintSettings = settingsGTK->GetGtkPrintSettings();
+  NS_ENSURE_STATE(gtkPrintSettings);
+
+  gtk_print_settings_foreach(gtkPrintSettings,
+                             serialize_gtk_printsettings_to_printdata, data);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsServiceGTK::DeserializeToPrintSettings(
+    const PrintData& data, nsIPrintSettings* settings) {
+  nsCOMPtr<nsPrintSettingsGTK> settingsGTK(do_QueryInterface(settings));
+  NS_ENSURE_STATE(settingsGTK);
+
+  nsresult rv =
+      nsPrintSettingsService::DeserializeToPrintSettings(data, settings);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Instead of re-using the GtkPrintSettings that nsIPrintSettings is
+  // wrapping, we'll create a new one to deserialize to and replace it
+  // within nsIPrintSettings.
+  GtkPrintSettings* newGtkPrintSettings = gtk_print_settings_new();
+
+  for (uint32_t i = 0; i < data.GTKPrintSettings().Length(); ++i) {
+    CStringKeyValue pair = data.GTKPrintSettings()[i];
+    gtk_print_settings_set(newGtkPrintSettings, pair.key().get(),
+                           pair.value().get());
+  }
+
+  settingsGTK->SetGtkPrintSettings(newGtkPrintSettings);
+
+  // nsPrintSettingsGTK is holding a reference to newGtkPrintSettings
+  g_object_unref(newGtkPrintSettings);
+  newGtkPrintSettings = nullptr;
+  return NS_OK;
+}
+
+nsresult nsPrintSettingsServiceGTK::_CreatePrintSettings(
+    nsIPrintSettings** _retval) {
+  *_retval = nullptr;
+  nsPrintSettingsGTK* printSettings =
+      new nsPrintSettingsGTK();  // does not initially ref count
+  NS_ENSURE_TRUE(printSettings, NS_ERROR_OUT_OF_MEMORY);
+
+  NS_ADDREF(*_retval = printSettings);  // ref count
+
+  return NS_OK;
+}
diff --git a/widget/gtk/nsPrintSettingsServiceGTK.h b/widget/gtk/nsPrintSettingsServiceGTK.h
new file mode 100644
index 0000000000..d26f543110
--- /dev/null
+++ b/widget/gtk/nsPrintSettingsServiceGTK.h
@@ -0,0 +1,33 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrintSettingsServiceGTK_h
+#define nsPrintSettingsServiceGTK_h
+
+#include "nsPrintSettingsService.h"
+
+namespace mozilla {
+namespace embedding {
+class PrintData;
+}  // namespace embedding
+}  // namespace mozilla
+
+class nsPrintSettingsServiceGTK final : public nsPrintSettingsService {
+ public:
+  nsPrintSettingsServiceGTK() = default;
+
+  NS_IMETHODIMP SerializeToPrintData(
+      nsIPrintSettings* aSettings,
+      mozilla::embedding::PrintData* data) override;
+
+  NS_IMETHODIMP DeserializeToPrintSettings(
+      const mozilla::embedding::PrintData& data,
+      nsIPrintSettings* settings) override;
+
+  virtual nsresult _CreatePrintSettings(nsIPrintSettings** _retval) override;
+};
+
+#endif  // nsPrintSettingsServiceGTK_h
diff --git a/widget/gtk/nsShmImage.cpp b/widget/gtk/nsShmImage.cpp
new file mode 100644
index 0000000000..7208b7075f
--- /dev/null
+++ b/widget/gtk/nsShmImage.cpp
@@ -0,0 +1,326 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsShmImage.h"
+
+#ifdef MOZ_HAVE_SHMIMAGE
+#  include "mozilla/X11Util.h"
+#  include "mozilla/gfx/gfxVars.h"
+#  include "mozilla/ipc/SharedMemory.h"
+#  include "gfxPlatform.h"
+#  include "nsPrintfCString.h"
+#  include "nsTArray.h"
+
+#  include <dlfcn.h>
+#  include <errno.h>
+#  include <string.h>
+#  include <sys/ipc.h>
+#  include <sys/shm.h>
+
+extern "C" {
+#  include <X11/ImUtil.h>
+}
+
+using namespace mozilla::ipc;
+using namespace mozilla::gfx;
+
+nsShmImage::nsShmImage(Display* aDisplay, Drawable aWindow, Visual* aVisual,
+                       unsigned int aDepth)
+    : mDisplay(aDisplay),
+      mConnection(XGetXCBConnection(aDisplay)),
+      mWindow(aWindow),
+      mVisual(aVisual),
+      mDepth(aDepth),
+      mFormat(mozilla::gfx::SurfaceFormat::UNKNOWN),
+      mSize(0, 0),
+      mStride(0),
+      mPixmap(XCB_NONE),
+      mGC(XCB_NONE),
+      mRequestPending(false),
+      mShmSeg(XCB_NONE),
+      mShmId(-1),
+      mShmAddr(nullptr) {
+  mozilla::PodZero(&mSyncRequest);
+}
+
+nsShmImage::~nsShmImage() { DestroyImage(); }
+
+// If XShm isn't available to our client, we'll try XShm once, fail,
+// set this to false and then never try again.
+static bool gShmAvailable = true;
+bool nsShmImage::UseShm() { return gShmAvailable; }
+
+bool nsShmImage::CreateShmSegment() {
+  size_t size = SharedMemory::PageAlignedSize(mStride * mSize.height);
+
+#  if defined(__OpenBSD__) && defined(MOZ_SANDBOX)
+  static mozilla::LazyLogModule sPledgeLog("SandboxPledge");
+  MOZ_LOG(sPledgeLog, mozilla::LogLevel::Debug,
+          ("%s called when pledged, returning false\n", __func__));
+  return false;
+#  endif
+  mShmId = shmget(IPC_PRIVATE, size, IPC_CREAT | 0600);
+  if (mShmId == -1) {
+    return false;
+  }
+  mShmAddr = (uint8_t*)shmat(mShmId, nullptr, 0);
+  mShmSeg = xcb_generate_id(mConnection);
+
+  // Mark the handle removed so that it will destroy the segment when unmapped.
+  shmctl(mShmId, IPC_RMID, nullptr);
+
+  if (mShmAddr == (void*)-1) {
+    // Since mapping failed, the segment is already destroyed.
+    mShmId = -1;
+
+    nsPrintfCString warning("shmat(): %s (%d)\n", strerror(errno), errno);
+    NS_WARNING(warning.get());
+    return false;
+  }
+
+#  ifdef DEBUG
+  struct shmid_ds info;
+  if (shmctl(mShmId, IPC_STAT, &info) < 0) {
+    return false;
+  }
+
+  MOZ_ASSERT(size <= info.shm_segsz, "Segment doesn't have enough space!");
+#  endif
+
+  return true;
+}
+
+void nsShmImage::DestroyShmSegment() {
+  if (mShmId != -1) {
+    shmdt(mShmAddr);
+    mShmId = -1;
+  }
+}
+
+static bool gShmInitialized = false;
+static bool gUseShmPixmaps = false;
+
+bool nsShmImage::InitExtension() {
+  if (gShmInitialized) {
+    return gShmAvailable;
+  }
+
+  gShmInitialized = true;
+
+  // Bugs 1397918, 1293474 - race condition in libxcb fixed upstream as of
+  // version 1.11. Since we can't query libxcb's version directly, the only
+  // other option is to check for symbols that were added after 1.11.
+  // xcb_discard_reply64 was added in 1.11.1, so check for existence of
+  // that to verify we are using a version of libxcb with the bug fixed.
+  // Otherwise, we can't risk using libxcb due to aforementioned crashes.
+  if (!dlsym(RTLD_DEFAULT, "xcb_discard_reply64")) {
+    gShmAvailable = false;
+    return false;
+  }
+
+  const xcb_query_extension_reply_t* extReply;
+  extReply = xcb_get_extension_data(mConnection, &xcb_shm_id);
+  if (!extReply || !extReply->present) {
+    gShmAvailable = false;
+    return false;
+  }
+
+  xcb_shm_query_version_reply_t* shmReply = xcb_shm_query_version_reply(
+      mConnection, xcb_shm_query_version(mConnection), nullptr);
+
+  if (!shmReply) {
+    gShmAvailable = false;
+    return false;
+  }
+
+  gUseShmPixmaps = shmReply->shared_pixmaps &&
+                   shmReply->pixmap_format == XCB_IMAGE_FORMAT_Z_PIXMAP;
+
+  free(shmReply);
+
+  return true;
+}
+
+bool nsShmImage::CreateImage(const IntSize& aSize) {
+  MOZ_ASSERT(mConnection && mVisual);
+
+  if (!InitExtension()) {
+    return false;
+  }
+
+  mSize = aSize;
+
+  BackendType backend = gfxVars::ContentBackend();
+
+  mFormat = SurfaceFormat::UNKNOWN;
+  switch (mDepth) {
+    case 32:
+      if (mVisual->red_mask == 0xff0000 && mVisual->green_mask == 0xff00 &&
+          mVisual->blue_mask == 0xff) {
+        mFormat = SurfaceFormat::B8G8R8A8;
+      }
+      break;
+    case 24:
+      // Only support the BGRX layout, and report it as BGRA to the compositor.
+      // The alpha channel will be discarded when we put the image.
+      // Cairo/pixman lacks some fast paths for compositing BGRX onto BGRA, so
+      // just report it as BGRX directly in that case.
+      if (mVisual->red_mask == 0xff0000 && mVisual->green_mask == 0xff00 &&
+          mVisual->blue_mask == 0xff) {
+        mFormat = backend == BackendType::CAIRO ? SurfaceFormat::B8G8R8X8
+                                                : SurfaceFormat::B8G8R8A8;
+      }
+      break;
+    case 16:
+      if (mVisual->red_mask == 0xf800 && mVisual->green_mask == 0x07e0 &&
+          mVisual->blue_mask == 0x1f) {
+        mFormat = SurfaceFormat::R5G6B5_UINT16;
+      }
+      break;
+  }
+
+  if (mFormat == SurfaceFormat::UNKNOWN) {
+    NS_WARNING("Unsupported XShm Image format!");
+    gShmAvailable = false;
+    return false;
+  }
+
+  // Round up stride to the display's scanline pad (in bits) as XShm expects.
+  int scanlinePad = _XGetScanlinePad(mDisplay, mDepth);
+  int bitsPerPixel = _XGetBitsPerPixel(mDisplay, mDepth);
+  int bitsPerLine =
+      ((bitsPerPixel * aSize.width + scanlinePad - 1) / scanlinePad) *
+      scanlinePad;
+  mStride = bitsPerLine / 8;
+
+  if (!CreateShmSegment()) {
+    DestroyImage();
+    return false;
+  }
+
+  xcb_generic_error_t* error;
+  xcb_void_cookie_t cookie;
+
+  cookie = xcb_shm_attach_checked(mConnection, mShmSeg, mShmId, 0);
+
+  if ((error = xcb_request_check(mConnection, cookie))) {
+    NS_WARNING("Failed to attach MIT-SHM segment.");
+    DestroyImage();
+    gShmAvailable = false;
+    free(error);
+    return false;
+  }
+
+  if (gUseShmPixmaps) {
+    mPixmap = xcb_generate_id(mConnection);
+    cookie = xcb_shm_create_pixmap_checked(mConnection, mPixmap, mWindow,
+                                           aSize.width, aSize.height, mDepth,
+                                           mShmSeg, 0);
+
+    if ((error = xcb_request_check(mConnection, cookie))) {
+      // Disable shared pixmaps permanently if creation failed.
+      mPixmap = XCB_NONE;
+      gUseShmPixmaps = false;
+      free(error);
+    }
+  }
+
+  return true;
+}
+
+void nsShmImage::DestroyImage() {
+  if (mGC) {
+    xcb_free_gc(mConnection, mGC);
+    mGC = XCB_NONE;
+  }
+  if (mPixmap != XCB_NONE) {
+    xcb_free_pixmap(mConnection, mPixmap);
+    mPixmap = XCB_NONE;
+  }
+  if (mShmSeg != XCB_NONE) {
+    xcb_shm_detach_checked(mConnection, mShmSeg);
+    mShmSeg = XCB_NONE;
+  }
+  DestroyShmSegment();
+  // Avoid leaking any pending reply.  No real need to wait but CentOS 6 build
+  // machines don't have xcb_discard_reply().
+  WaitIfPendingReply();
+}
+
+// Wait for any in-flight shm-affected requests to complete.
+// Typically X clients would wait for a XShmCompletionEvent to be received,
+// but this works as it's sent immediately after the request is sent.
+void nsShmImage::WaitIfPendingReply() {
+  if (mRequestPending) {
+    xcb_get_input_focus_reply_t* reply =
+        xcb_get_input_focus_reply(mConnection, mSyncRequest, nullptr);
+    free(reply);
+    mRequestPending = false;
+  }
+}
+
+already_AddRefed<DrawTarget> nsShmImage::CreateDrawTarget(
+    const mozilla::LayoutDeviceIntRegion& aRegion) {
+  WaitIfPendingReply();
+
+  // Due to bug 1205045, we must avoid making GTK calls off the main thread to
+  // query window size. Instead we just track the largest offset within the
+  // image we are drawing to and grow the image to accomodate it. Since usually
+  // the entire window is invalidated on the first paint to it, this should grow
+  // the image to the necessary size quickly without many intermediate
+  // reallocations.
+  IntRect bounds = aRegion.GetBounds().ToUnknownRect();
+  IntSize size(bounds.XMost(), bounds.YMost());
+  if (size.width > mSize.width || size.height > mSize.height) {
+    DestroyImage();
+    if (!CreateImage(size)) {
+      return nullptr;
+    }
+  }
+
+  return gfxPlatform::CreateDrawTargetForData(
+      reinterpret_cast<unsigned char*>(mShmAddr) + bounds.y * mStride +
+          bounds.x * BytesPerPixel(mFormat),
+      bounds.Size(), mStride, mFormat);
+}
+
+void nsShmImage::Put(const mozilla::LayoutDeviceIntRegion& aRegion) {
+  AutoTArray<xcb_rectangle_t, 32> xrects;
+  xrects.SetCapacity(aRegion.GetNumRects());
+
+  for (auto iter = aRegion.RectIter(); !iter.Done(); iter.Next()) {
+    const mozilla::LayoutDeviceIntRect& r = iter.Get();
+    xcb_rectangle_t xrect = {(short)r.x, (short)r.y, (unsigned short)r.width,
+                             (unsigned short)r.height};
+    xrects.AppendElement(xrect);
+  }
+
+  if (!mGC) {
+    mGC = xcb_generate_id(mConnection);
+    xcb_create_gc(mConnection, mGC, mWindow, 0, nullptr);
+  }
+
+  xcb_set_clip_rectangles(mConnection, XCB_CLIP_ORDERING_YX_BANDED, mGC, 0, 0,
+                          xrects.Length(), xrects.Elements());
+
+  if (mPixmap != XCB_NONE) {
+    xcb_copy_area(mConnection, mPixmap, mWindow, mGC, 0, 0, 0, 0, mSize.width,
+                  mSize.height);
+  } else {
+    xcb_shm_put_image(mConnection, mWindow, mGC, mSize.width, mSize.height, 0,
+                      0, mSize.width, mSize.height, 0, 0, mDepth,
+                      XCB_IMAGE_FORMAT_Z_PIXMAP, 0, mShmSeg, 0);
+  }
+
+  // Send a request that returns a response so that we don't have to start a
+  // sync in nsShmImage::CreateDrawTarget.
+  mSyncRequest = xcb_get_input_focus(mConnection);
+  mRequestPending = true;
+
+  xcb_flush(mConnection);
+}
+
+#endif  // MOZ_HAVE_SHMIMAGE
diff --git a/widget/gtk/nsShmImage.h b/widget/gtk/nsShmImage.h
new file mode 100644
index 0000000000..2d92c39e0d
--- /dev/null
+++ b/widget/gtk/nsShmImage.h
@@ -0,0 +1,75 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_nsShmImage_h__
+#define __mozilla_widget_nsShmImage_h__
+
+#if defined(MOZ_X11)
+#  define MOZ_HAVE_SHMIMAGE
+#endif
+
+#ifdef MOZ_HAVE_SHMIMAGE
+
+#  include "mozilla/gfx/2D.h"
+#  include "nsIWidget.h"
+#  include "Units.h"
+
+#  include <X11/Xlib-xcb.h>
+#  include <xcb/shm.h>
+
+class nsShmImage {
+  // bug 1168843, compositor thread may create shared memory instances that are
+  // destroyed by main thread on shutdown, so this must use thread-safe RC to
+  // avoid hitting assertion
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(nsShmImage)
+
+ public:
+  static bool UseShm();
+
+  already_AddRefed<mozilla::gfx::DrawTarget> CreateDrawTarget(
+      const mozilla::LayoutDeviceIntRegion& aRegion);
+
+  void Put(const mozilla::LayoutDeviceIntRegion& aRegion);
+
+  nsShmImage(Display* aDisplay, Drawable aWindow, Visual* aVisual,
+             unsigned int aDepth);
+
+ private:
+  ~nsShmImage();
+
+  bool InitExtension();
+
+  bool CreateShmSegment();
+  void DestroyShmSegment();
+
+  bool CreateImage(const mozilla::gfx::IntSize& aSize);
+  void DestroyImage();
+
+  void WaitIfPendingReply();
+
+  Display* mDisplay;
+  xcb_connection_t* mConnection;
+  Window mWindow;
+  Visual* mVisual;
+  unsigned int mDepth;
+
+  mozilla::gfx::SurfaceFormat mFormat;
+  mozilla::gfx::IntSize mSize;
+  int mStride;
+
+  xcb_pixmap_t mPixmap;
+  xcb_gcontext_t mGC;
+  xcb_get_input_focus_cookie_t mSyncRequest;
+  bool mRequestPending;
+
+  xcb_shm_seg_t mShmSeg;
+  int mShmId;
+  uint8_t* mShmAddr;
+};
+
+#endif  // MOZ_HAVE_SHMIMAGE
+
+#endif
diff --git a/widget/gtk/nsSound.cpp b/widget/gtk/nsSound.cpp
new file mode 100644
index 0000000000..0530c73224
--- /dev/null
+++ b/widget/gtk/nsSound.cpp
@@ -0,0 +1,397 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <string.h>
+
+#include "nscore.h"
+#include "prlink.h"
+
+#include "nsSound.h"
+
+#include "HeadlessSound.h"
+#include "nsIURL.h"
+#include "nsNetUtil.h"
+#include "nsIChannel.h"
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "nsDirectoryService.h"
+#include "nsDirectoryServiceDefs.h"
+#include "mozilla/FileUtils.h"
+#include "mozilla/Unused.h"
+#include "mozilla/WidgetUtils.h"
+#include "nsIXULAppInfo.h"
+#include "nsContentUtils.h"
+#include "gfxPlatform.h"
+#include "mozilla/ClearOnShutdown.h"
+
+#include <stdio.h>
+#include <unistd.h>
+
+#include <gtk/gtk.h>
+static PRLibrary* libcanberra = nullptr;
+
+/* used to play sounds with libcanberra. */
+typedef struct _ca_context ca_context;
+typedef struct _ca_proplist ca_proplist;
+
+typedef void (*ca_finish_callback_t)(ca_context* c, uint32_t id, int error_code,
+                                     void* userdata);
+
+typedef int (*ca_context_create_fn)(ca_context**);
+typedef int (*ca_context_destroy_fn)(ca_context*);
+typedef int (*ca_context_play_fn)(ca_context* c, uint32_t id, ...);
+typedef int (*ca_context_change_props_fn)(ca_context* c, ...);
+typedef int (*ca_proplist_create_fn)(ca_proplist**);
+typedef int (*ca_proplist_destroy_fn)(ca_proplist*);
+typedef int (*ca_proplist_sets_fn)(ca_proplist* c, const char* key,
+                                   const char* value);
+typedef int (*ca_context_play_full_fn)(ca_context* c, uint32_t id,
+                                       ca_proplist* p, ca_finish_callback_t cb,
+                                       void* userdata);
+
+static ca_context_create_fn ca_context_create;
+static ca_context_destroy_fn ca_context_destroy;
+static ca_context_play_fn ca_context_play;
+static ca_context_change_props_fn ca_context_change_props;
+static ca_proplist_create_fn ca_proplist_create;
+static ca_proplist_destroy_fn ca_proplist_destroy;
+static ca_proplist_sets_fn ca_proplist_sets;
+static ca_context_play_full_fn ca_context_play_full;
+
+struct ScopedCanberraFile {
+  explicit ScopedCanberraFile(nsIFile* file) : mFile(file){};
+
+  ~ScopedCanberraFile() {
+    if (mFile) {
+      mFile->Remove(false);
+    }
+  }
+
+  void forget() { mozilla::Unused << mFile.forget(); }
+  nsIFile* operator->() { return mFile; }
+  operator nsIFile*() { return mFile; }
+
+  nsCOMPtr<nsIFile> mFile;
+};
+
+static ca_context* ca_context_get_default() {
+  // This allows us to avoid race conditions with freeing the context by handing
+  // that responsibility to Glib, and still use one context at a time
+  static GPrivate ctx_private =
+      G_PRIVATE_INIT((GDestroyNotify)ca_context_destroy);
+
+  ca_context* ctx = (ca_context*)g_private_get(&ctx_private);
+
+  if (ctx) {
+    return ctx;
+  }
+
+  ca_context_create(&ctx);
+  if (!ctx) {
+    return nullptr;
+  }
+
+  g_private_set(&ctx_private, ctx);
+
+  GtkSettings* settings = gtk_settings_get_default();
+  if (g_object_class_find_property(G_OBJECT_GET_CLASS(settings),
+                                   "gtk-sound-theme-name")) {
+    gchar* sound_theme_name = nullptr;
+    g_object_get(settings, "gtk-sound-theme-name", &sound_theme_name, nullptr);
+
+    if (sound_theme_name) {
+      ca_context_change_props(ctx, "canberra.xdg-theme.name", sound_theme_name,
+                              nullptr);
+      g_free(sound_theme_name);
+    }
+  }
+
+  nsAutoString wbrand;
+  mozilla::widget::WidgetUtils::GetBrandShortName(wbrand);
+  ca_context_change_props(ctx, "application.name",
+                          NS_ConvertUTF16toUTF8(wbrand).get(), nullptr);
+
+  nsCOMPtr<nsIXULAppInfo> appInfo =
+      do_GetService("@mozilla.org/xre/app-info;1");
+  if (appInfo) {
+    nsAutoCString version;
+    appInfo->GetVersion(version);
+
+    ca_context_change_props(ctx, "application.version", version.get(), nullptr);
+  }
+
+  ca_context_change_props(ctx, "application.icon_name", MOZ_APP_NAME, nullptr);
+
+  return ctx;
+}
+
+static void ca_finish_cb(ca_context* c, uint32_t id, int error_code,
+                         void* userdata) {
+  nsIFile* file = reinterpret_cast<nsIFile*>(userdata);
+  if (file) {
+    file->Remove(false);
+    NS_RELEASE(file);
+  }
+}
+
+NS_IMPL_ISUPPORTS(nsSound, nsISound, nsIStreamLoaderObserver)
+
+////////////////////////////////////////////////////////////////////////
+nsSound::nsSound() { mInited = false; }
+
+nsSound::~nsSound() = default;
+
+NS_IMETHODIMP
+nsSound::Init() {
+  // This function is designed so that no library is compulsory, and
+  // one library missing doesn't cause the other(s) to not be used.
+  if (mInited) return NS_OK;
+
+  mInited = true;
+
+  if (!libcanberra) {
+    libcanberra = PR_LoadLibrary("libcanberra.so.0");
+    if (libcanberra) {
+      ca_context_create = (ca_context_create_fn)PR_FindFunctionSymbol(
+          libcanberra, "ca_context_create");
+      if (!ca_context_create) {
+#ifdef MOZ_TSAN
+        // With TSan, we cannot unload libcanberra once we have loaded it
+        // because TSan does not support unloading libraries that are matched
+        // from its suppression list. Hence we just keep the library loaded in
+        // TSan builds.
+        libcanberra = nullptr;
+        return NS_OK;
+#endif
+        PR_UnloadLibrary(libcanberra);
+        libcanberra = nullptr;
+      } else {
+        // at this point we know we have a good libcanberra library
+        ca_context_destroy = (ca_context_destroy_fn)PR_FindFunctionSymbol(
+            libcanberra, "ca_context_destroy");
+        ca_context_play = (ca_context_play_fn)PR_FindFunctionSymbol(
+            libcanberra, "ca_context_play");
+        ca_context_change_props =
+            (ca_context_change_props_fn)PR_FindFunctionSymbol(
+                libcanberra, "ca_context_change_props");
+        ca_proplist_create = (ca_proplist_create_fn)PR_FindFunctionSymbol(
+            libcanberra, "ca_proplist_create");
+        ca_proplist_destroy = (ca_proplist_destroy_fn)PR_FindFunctionSymbol(
+            libcanberra, "ca_proplist_destroy");
+        ca_proplist_sets = (ca_proplist_sets_fn)PR_FindFunctionSymbol(
+            libcanberra, "ca_proplist_sets");
+        ca_context_play_full = (ca_context_play_full_fn)PR_FindFunctionSymbol(
+            libcanberra, "ca_context_play_full");
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+/* static */
+void nsSound::Shutdown() {
+#ifndef MOZ_TSAN
+  if (libcanberra) {
+    PR_UnloadLibrary(libcanberra);
+    libcanberra = nullptr;
+  }
+#endif
+}
+
+namespace mozilla {
+namespace sound {
+StaticRefPtr<nsISound> sInstance;
+}
+}  // namespace mozilla
+/* static */
+already_AddRefed<nsISound> nsSound::GetInstance() {
+  using namespace mozilla::sound;
+
+  if (!sInstance) {
+    if (gfxPlatform::IsHeadless()) {
+      sInstance = new mozilla::widget::HeadlessSound();
+    } else {
+      sInstance = new nsSound();
+    }
+    ClearOnShutdown(&sInstance);
+  }
+
+  RefPtr<nsISound> service = sInstance.get();
+  return service.forget();
+}
+
+NS_IMETHODIMP nsSound::OnStreamComplete(nsIStreamLoader* aLoader,
+                                        nsISupports* context, nsresult aStatus,
+                                        uint32_t dataLen, const uint8_t* data) {
+  // print a load error on bad status, and return
+  if (NS_FAILED(aStatus)) {
+#ifdef DEBUG
+    if (aLoader) {
+      nsCOMPtr<nsIRequest> request;
+      aLoader->GetRequest(getter_AddRefs(request));
+      if (request) {
+        nsCOMPtr<nsIURI> uri;
+        nsCOMPtr<nsIChannel> channel = do_QueryInterface(request);
+        if (channel) {
+          channel->GetURI(getter_AddRefs(uri));
+          if (uri) {
+            printf("Failed to load %s\n", uri->GetSpecOrDefault().get());
+          }
+        }
+      }
+    }
+#endif
+    return aStatus;
+  }
+
+  nsCOMPtr<nsIFile> tmpFile;
+  nsDirectoryService::gService->Get(NS_OS_TEMP_DIR, NS_GET_IID(nsIFile),
+                                    getter_AddRefs(tmpFile));
+
+  nsresult rv =
+      tmpFile->AppendNative(nsDependentCString("mozilla_audio_sample"));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  rv = tmpFile->CreateUnique(nsIFile::NORMAL_FILE_TYPE, PR_IRUSR | PR_IWUSR);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  ScopedCanberraFile canberraFile(tmpFile);
+
+  mozilla::AutoFDClose fd;
+  rv = canberraFile->OpenNSPRFileDesc(PR_WRONLY, PR_IRUSR | PR_IWUSR,
+                                      getter_Transfers(fd));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // XXX: Should we do this on another thread?
+  uint32_t length = dataLen;
+  while (length > 0) {
+    int32_t amount = PR_Write(fd.get(), data, length);
+    if (amount < 0) {
+      return NS_ERROR_FAILURE;
+    }
+    length -= amount;
+    data += amount;
+  }
+
+  ca_context* ctx = ca_context_get_default();
+  if (!ctx) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  ca_proplist* p;
+  ca_proplist_create(&p);
+  if (!p) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  nsAutoCString path;
+  rv = canberraFile->GetNativePath(path);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  ca_proplist_sets(p, "media.filename", path.get());
+  if (ca_context_play_full(ctx, 0, p, ca_finish_cb, canberraFile) >= 0) {
+    // Don't delete the temporary file here if ca_context_play_full succeeds
+    canberraFile.forget();
+  }
+  ca_proplist_destroy(p);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsSound::Beep() {
+  ::gdk_beep();
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsSound::Play(nsIURL* aURL) {
+  if (!mInited) Init();
+
+  if (!libcanberra) return NS_ERROR_NOT_AVAILABLE;
+
+  nsresult rv;
+  if (aURL->SchemeIs("file")) {
+    ca_context* ctx = ca_context_get_default();
+    if (!ctx) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    nsAutoCString spec;
+    rv = aURL->GetSpec(spec);
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+    gchar* path = g_filename_from_uri(spec.get(), nullptr, nullptr);
+    if (!path) {
+      return NS_ERROR_FILE_UNRECOGNIZED_PATH;
+    }
+
+    ca_context_play(ctx, 0, "media.filename", path, nullptr);
+    g_free(path);
+  } else {
+    nsCOMPtr<nsIStreamLoader> loader;
+    rv = NS_NewStreamLoader(
+        getter_AddRefs(loader), aURL,
+        this,  // aObserver
+        nsContentUtils::GetSystemPrincipal(),
+        nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
+        nsIContentPolicy::TYPE_OTHER);
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP nsSound::PlayEventSound(uint32_t aEventId) {
+  if (!mInited) Init();
+
+  if (!libcanberra) return NS_OK;
+
+  // Do we even want alert sounds?
+  GtkSettings* settings = gtk_settings_get_default();
+
+  if (g_object_class_find_property(G_OBJECT_GET_CLASS(settings),
+                                   "gtk-enable-event-sounds")) {
+    gboolean enable_sounds = TRUE;
+    g_object_get(settings, "gtk-enable-event-sounds", &enable_sounds, nullptr);
+
+    if (!enable_sounds) {
+      return NS_OK;
+    }
+  }
+
+  ca_context* ctx = ca_context_get_default();
+  if (!ctx) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  switch (aEventId) {
+    case EVENT_ALERT_DIALOG_OPEN:
+      ca_context_play(ctx, 0, "event.id", "dialog-warning", nullptr);
+      break;
+    case EVENT_CONFIRM_DIALOG_OPEN:
+      ca_context_play(ctx, 0, "event.id", "dialog-question", nullptr);
+      break;
+    case EVENT_NEW_MAIL_RECEIVED:
+      ca_context_play(ctx, 0, "event.id", "message-new-email", nullptr);
+      break;
+    case EVENT_MENU_EXECUTE:
+      ca_context_play(ctx, 0, "event.id", "menu-click", nullptr);
+      break;
+    case EVENT_MENU_POPUP:
+      ca_context_play(ctx, 0, "event.id", "menu-popup", nullptr);
+      break;
+  }
+  return NS_OK;
+}
diff --git a/widget/gtk/nsSound.h b/widget/gtk/nsSound.h
new file mode 100644
index 0000000000..8f4fe5a04b
--- /dev/null
+++ b/widget/gtk/nsSound.h
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsSound_h__
+#define __nsSound_h__
+
+#include "nsISound.h"
+#include "nsIStreamLoader.h"
+
+#include <gtk/gtk.h>
+
+class nsSound : public nsISound, public nsIStreamLoaderObserver {
+ public:
+  nsSound();
+
+  static void Shutdown();
+  static already_AddRefed<nsISound> GetInstance();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISOUND
+  NS_DECL_NSISTREAMLOADEROBSERVER
+
+ private:
+  virtual ~nsSound();
+
+  bool mInited;
+};
+
+#endif /* __nsSound_h__ */
diff --git a/widget/gtk/nsToolkit.cpp b/widget/gtk/nsToolkit.cpp
new file mode 100644
index 0000000000..aaf13239e0
--- /dev/null
+++ b/widget/gtk/nsToolkit.cpp
@@ -0,0 +1,24 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nscore.h"  // needed for 'nullptr'
+#include "nsGTKToolkit.h"
+
+nsGTKToolkit* nsGTKToolkit::gToolkit = nullptr;
+
+//-------------------------------------------------------------------------------
+// Return the toolkit. If a toolkit does not yet exist, then one will be
+// created.
+//-------------------------------------------------------------------------------
+// static
+nsGTKToolkit* nsGTKToolkit::GetToolkit() {
+  if (!gToolkit) {
+    gToolkit = new nsGTKToolkit();
+  }
+
+  return gToolkit;
+}
diff --git a/widget/gtk/nsUserIdleServiceGTK.cpp b/widget/gtk/nsUserIdleServiceGTK.cpp
new file mode 100644
index 0000000000..4cdc5ba13d
--- /dev/null
+++ b/widget/gtk/nsUserIdleServiceGTK.cpp
@@ -0,0 +1,317 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <gtk/gtk.h>
+
+#include "nsUserIdleServiceGTK.h"
+#include "nsDebug.h"
+#include "prlink.h"
+#include "mozilla/Logging.h"
+#include "WidgetUtilsGtk.h"
+#ifdef MOZ_X11
+#  include <X11/Xlib.h>
+#  include <X11/Xutil.h>
+#  include <gdk/gdkx.h>
+#endif
+#ifdef MOZ_ENABLE_DBUS
+#  include <gio/gio.h>
+#  include "AsyncDBus.h"
+#  include "WakeLockListener.h"
+#  include "nsIObserverService.h"
+#  include "mozilla/UniquePtrExtensions.h"
+#endif
+
+using mozilla::LogLevel;
+static mozilla::LazyLogModule sIdleLog("nsIUserIdleService");
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+#ifdef MOZ_X11
+typedef struct {
+  Window window;               // Screen saver window
+  int state;                   // ScreenSaver(Off,On,Disabled)
+  int kind;                    // ScreenSaver(Blanked,Internal,External)
+  unsigned long til_or_since;  // milliseconds since/til screensaver kicks in
+  unsigned long idle;          // milliseconds idle
+  unsigned long event_mask;    // event stuff
+} XScreenSaverInfo;
+
+typedef bool (*_XScreenSaverQueryExtension_fn)(Display* dpy, int* event_base,
+                                               int* error_base);
+typedef XScreenSaverInfo* (*_XScreenSaverAllocInfo_fn)(void);
+typedef void (*_XScreenSaverQueryInfo_fn)(Display* dpy, Drawable drw,
+                                          XScreenSaverInfo* info);
+
+class UserIdleServiceX11 : public UserIdleServiceImpl {
+ public:
+  bool PollIdleTime(uint32_t* aIdleTime) override {
+    // Ask xscreensaver about idle time:
+    *aIdleTime = 0;
+
+    // We might not have a display (cf. in xpcshell)
+    Display* dplay = GDK_DISPLAY_XDISPLAY(gdk_display_get_default());
+    if (!dplay) {
+      MOZ_LOG(sIdleLog, LogLevel::Warning, ("No display found!\n"));
+      return false;
+    }
+
+    int event_base, error_base;
+    if (mXSSQueryExtension(dplay, &event_base, &error_base)) {
+      if (!mXssInfo) mXssInfo = mXSSAllocInfo();
+      if (!mXssInfo) return false;
+      mXSSQueryInfo(dplay, GDK_ROOT_WINDOW(), mXssInfo);
+      *aIdleTime = mXssInfo->idle;
+      MOZ_LOG(sIdleLog, LogLevel::Info,
+              ("UserIdleServiceX11::PollIdleTime() %d\n", *aIdleTime));
+      return true;
+    }
+    // If we get here, we couldn't get to XScreenSaver:
+    MOZ_LOG(sIdleLog, LogLevel::Warning,
+            ("XSSQueryExtension returned false!\n"));
+    return false;
+  }
+
+  bool ProbeImplementation() override {
+    MOZ_LOG(sIdleLog, LogLevel::Info,
+            ("UserIdleServiceX11::UserIdleServiceX11()\n"));
+
+    if (!mozilla::widget::GdkIsX11Display()) {
+      return false;
+    }
+
+    // This will leak - See comments in ~UserIdleServiceX11().
+    PRLibrary* xsslib = PR_LoadLibrary("libXss.so.1");
+    if (!xsslib)  // ouch.
+    {
+      MOZ_LOG(sIdleLog, LogLevel::Warning, ("Failed to find libXss.so!\n"));
+      return false;
+    }
+
+    mXSSQueryExtension = (_XScreenSaverQueryExtension_fn)PR_FindFunctionSymbol(
+        xsslib, "XScreenSaverQueryExtension");
+    mXSSAllocInfo = (_XScreenSaverAllocInfo_fn)PR_FindFunctionSymbol(
+        xsslib, "XScreenSaverAllocInfo");
+    mXSSQueryInfo = (_XScreenSaverQueryInfo_fn)PR_FindFunctionSymbol(
+        xsslib, "XScreenSaverQueryInfo");
+
+    if (!mXSSQueryExtension) {
+      MOZ_LOG(sIdleLog, LogLevel::Warning,
+              ("Failed to get XSSQueryExtension!\n"));
+    }
+    if (!mXSSAllocInfo) {
+      MOZ_LOG(sIdleLog, LogLevel::Warning, ("Failed to get XSSAllocInfo!\n"));
+    }
+    if (!mXSSQueryInfo) {
+      MOZ_LOG(sIdleLog, LogLevel::Warning, ("Failed to get XSSQueryInfo!\n"));
+    }
+    if (!mXSSQueryExtension || !mXSSAllocInfo || !mXSSQueryInfo) {
+      // We're missing X11 symbols
+      return false;
+    }
+
+    // UserIdleServiceX11 uses sync init, confirm it now.
+    mUserIdleServiceGTK->AcceptServiceCallback();
+    return true;
+  }
+
+  explicit UserIdleServiceX11(nsUserIdleServiceGTK* aUserIdleService)
+      : UserIdleServiceImpl(aUserIdleService){};
+
+  ~UserIdleServiceX11() {
+#  ifdef MOZ_X11
+    if (mXssInfo) {
+      XFree(mXssInfo);
+    }
+#  endif
+
+// It is not safe to unload libXScrnSaver until each display is closed because
+// the library registers callbacks through XESetCloseDisplay (Bug 397607).
+// (Also the library and its functions are scoped for the file not the object.)
+#  if 0
+        if (xsslib) {
+            PR_UnloadLibrary(xsslib);
+            xsslib = nullptr;
+        }
+#  endif
+  }
+
+ private:
+  XScreenSaverInfo* mXssInfo = nullptr;
+  _XScreenSaverQueryExtension_fn mXSSQueryExtension = nullptr;
+  _XScreenSaverAllocInfo_fn mXSSAllocInfo = nullptr;
+  _XScreenSaverQueryInfo_fn mXSSQueryInfo = nullptr;
+};
+#endif
+
+#ifdef MOZ_ENABLE_DBUS
+class UserIdleServiceMutter : public UserIdleServiceImpl {
+ public:
+  bool PollIdleTime(uint32_t* aIdleTime) override {
+    MOZ_LOG(sIdleLog, LogLevel::Info, ("PollIdleTime() request\n"));
+
+    // We're not ready yet
+    if (!mProxy) {
+      return false;
+    }
+
+    if (!mPollInProgress) {
+      mPollInProgress = true;
+      DBusProxyCall(mProxy, "GetIdletime", nullptr, G_DBUS_CALL_FLAGS_NONE, -1,
+                    mCancellable)
+          ->Then(
+              GetCurrentSerialEventTarget(), __func__,
+              // It's safe to capture this as we use mCancellable to stop
+              // listening.
+              [this](RefPtr<GVariant>&& aResult) {
+                if (!g_variant_is_of_type(aResult, G_VARIANT_TYPE_TUPLE) ||
+                    g_variant_n_children(aResult) != 1) {
+                  MOZ_LOG(sIdleLog, LogLevel::Info,
+                          ("PollIdleTime() Unexpected params type: %s\n",
+                           g_variant_get_type_string(aResult)));
+                  mLastIdleTime = 0;
+                  return;
+                }
+                RefPtr<GVariant> iTime =
+                    dont_AddRef(g_variant_get_child_value(aResult, 0));
+                if (!g_variant_is_of_type(iTime, G_VARIANT_TYPE_UINT64)) {
+                  MOZ_LOG(sIdleLog, LogLevel::Info,
+                          ("PollIdleTime() Unexpected params type: %s\n",
+                           g_variant_get_type_string(aResult)));
+                  mLastIdleTime = 0;
+                  return;
+                }
+                uint64_t idleTime = g_variant_get_uint64(iTime);
+                if (idleTime > std::numeric_limits<uint32_t>::max()) {
+                  idleTime = std::numeric_limits<uint32_t>::max();
+                }
+                mLastIdleTime = idleTime;
+                mPollInProgress = false;
+                MOZ_LOG(sIdleLog, LogLevel::Info,
+                        ("Async handler got %d\n", mLastIdleTime));
+              },
+              [this](GUniquePtr<GError>&& aError) {
+                mPollInProgress = false;
+                if (!IsCancelledGError(aError.get())) {
+                  MOZ_LOG(
+                      sIdleLog, LogLevel::Warning,
+                      ("Failed to call GetIdletime(): %s\n", aError->message));
+                  mUserIdleServiceGTK->RejectAndTryNextServiceCallback();
+                }
+              });
+    }
+
+    *aIdleTime = mLastIdleTime;
+    MOZ_LOG(sIdleLog, LogLevel::Info,
+            ("PollIdleTime() returns %d\n", *aIdleTime));
+    return true;
+  }
+
+  bool ProbeImplementation() override {
+    MOZ_LOG(sIdleLog, LogLevel::Info,
+            ("UserIdleServiceMutter::UserIdleServiceMutter()\n"));
+
+    mCancellable = dont_AddRef(g_cancellable_new());
+    CreateDBusProxyForBus(
+        G_BUS_TYPE_SESSION,
+        GDBusProxyFlags(G_DBUS_PROXY_FLAGS_DO_NOT_CONNECT_SIGNALS |
+                        G_DBUS_PROXY_FLAGS_DO_NOT_LOAD_PROPERTIES),
+        nullptr, "org.gnome.Mutter.IdleMonitor",
+        "/org/gnome/Mutter/IdleMonitor/Core", "org.gnome.Mutter.IdleMonitor",
+        mCancellable)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [this](RefPtr<GDBusProxy>&& aProxy) {
+              mProxy = std::move(aProxy);
+              mUserIdleServiceGTK->AcceptServiceCallback();
+            },
+            [this](GUniquePtr<GError>&& aError) {
+              if (!IsCancelledGError(aError.get())) {
+                mUserIdleServiceGTK->RejectAndTryNextServiceCallback();
+              }
+            });
+    return true;
+  }
+
+  explicit UserIdleServiceMutter(nsUserIdleServiceGTK* aUserIdleService)
+      : UserIdleServiceImpl(aUserIdleService){};
+
+  ~UserIdleServiceMutter() {
+    if (mCancellable) {
+      g_cancellable_cancel(mCancellable);
+      mCancellable = nullptr;
+    }
+    mProxy = nullptr;
+  }
+
+ private:
+  RefPtr<GDBusProxy> mProxy;
+  RefPtr<GCancellable> mCancellable;
+  uint32_t mLastIdleTime = 0;
+  bool mPollInProgress = false;
+};
+#endif
+
+void nsUserIdleServiceGTK::ProbeService() {
+  MOZ_LOG(sIdleLog, LogLevel::Info,
+          ("nsUserIdleServiceGTK::ProbeService() mIdleServiceType %d\n",
+           mIdleServiceType));
+  MOZ_ASSERT(!mIdleService);
+
+  switch (mIdleServiceType) {
+#ifdef MOZ_ENABLE_DBUS
+    case IDLE_SERVICE_MUTTER:
+      mIdleService = MakeUnique<UserIdleServiceMutter>(this);
+      break;
+#endif
+#ifdef MOZ_X11
+    case IDLE_SERVICE_XSCREENSAVER:
+      mIdleService = MakeUnique<UserIdleServiceX11>(this);
+      break;
+#endif
+    default:
+      return;
+  }
+
+  if (!mIdleService->ProbeImplementation()) {
+    RejectAndTryNextServiceCallback();
+  }
+}
+
+void nsUserIdleServiceGTK::AcceptServiceCallback() {
+  MOZ_LOG(sIdleLog, LogLevel::Info,
+          ("nsUserIdleServiceGTK::AcceptServiceCallback() type %d\n",
+           mIdleServiceType));
+  mIdleServiceInitialized = true;
+}
+
+void nsUserIdleServiceGTK::RejectAndTryNextServiceCallback() {
+  MOZ_LOG(sIdleLog, LogLevel::Info,
+          ("nsUserIdleServiceGTK::RejectAndTryNextServiceCallback() type %d\n",
+           mIdleServiceType));
+
+  // Delete recent non-working service
+  MOZ_ASSERT(mIdleService, "Nothing to reject?");
+  mIdleService = nullptr;
+  mIdleServiceInitialized = false;
+
+  mIdleServiceType++;
+  if (mIdleServiceType < IDLE_SERVICE_NONE) {
+    MOZ_LOG(sIdleLog, LogLevel::Info,
+            ("nsUserIdleServiceGTK try next idle service\n"));
+    ProbeService();
+  } else {
+    MOZ_LOG(sIdleLog, LogLevel::Info, ("nsUserIdleServiceGTK failed\n"));
+  }
+}
+
+bool nsUserIdleServiceGTK::PollIdleTime(uint32_t* aIdleTime) {
+  if (!mIdleServiceInitialized) {
+    return false;
+  }
+  return mIdleService->PollIdleTime(aIdleTime);
+}
diff --git a/widget/gtk/nsUserIdleServiceGTK.h b/widget/gtk/nsUserIdleServiceGTK.h
new file mode 100644
index 0000000000..1a5ed97840
--- /dev/null
+++ b/widget/gtk/nsUserIdleServiceGTK.h
@@ -0,0 +1,78 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsUserIdleServiceGTK_h__
+#define nsUserIdleServiceGTK_h__
+
+#include "nsUserIdleService.h"
+#include "mozilla/AppShutdown.h"
+#include "mozilla/UniquePtr.h"
+
+class nsUserIdleServiceGTK;
+
+class UserIdleServiceImpl {
+ public:
+  explicit UserIdleServiceImpl(nsUserIdleServiceGTK* aUserIdleService)
+      : mUserIdleServiceGTK(aUserIdleService){};
+
+  virtual bool PollIdleTime(uint32_t* aIdleTime) = 0;
+  virtual bool ProbeImplementation() = 0;
+
+  virtual ~UserIdleServiceImpl() = default;
+
+ protected:
+  nsUserIdleServiceGTK* mUserIdleServiceGTK;
+};
+
+#define IDLE_SERVICE_MUTTER 0
+#define IDLE_SERVICE_XSCREENSAVER 1
+#define IDLE_SERVICE_NONE 2
+
+class nsUserIdleServiceGTK : public nsUserIdleService {
+ public:
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(nsUserIdleServiceGTK, nsUserIdleService)
+
+  // The idle time in ms
+  virtual bool PollIdleTime(uint32_t* aIdleTime) override;
+
+  static already_AddRefed<nsUserIdleServiceGTK> GetInstance() {
+    RefPtr<nsUserIdleServiceGTK> idleService =
+        nsUserIdleService::GetInstance().downcast<nsUserIdleServiceGTK>();
+    if (!idleService) {
+      // Avoid late instantiation or resurrection during shutdown.
+      if (mozilla::AppShutdown::IsInOrBeyond(
+              mozilla::ShutdownPhase::AppShutdownConfirmed)) {
+        return nullptr;
+      }
+      idleService = new nsUserIdleServiceGTK();
+      idleService->ProbeService();
+    }
+
+    return idleService.forget();
+  }
+
+  void ProbeService();
+  void AcceptServiceCallback();
+  void RejectAndTryNextServiceCallback();
+
+ protected:
+  nsUserIdleServiceGTK() = default;
+
+ private:
+  ~nsUserIdleServiceGTK() = default;
+
+  mozilla::UniquePtr<UserIdleServiceImpl> mIdleService;
+#ifdef MOZ_ENABLE_DBUS
+  int mIdleServiceType = IDLE_SERVICE_MUTTER;
+#else
+  int mIdleServiceType = IDLE_SERVICE_XSCREENSAVER;
+#endif
+  // We have a working idle service.
+  bool mIdleServiceInitialized = false;
+};
+
+#endif  // nsUserIdleServiceGTK_h__
diff --git a/widget/gtk/nsWaylandDisplay.cpp b/widget/gtk/nsWaylandDisplay.cpp
new file mode 100644
index 0000000000..2a1021457a
--- /dev/null
+++ b/widget/gtk/nsWaylandDisplay.cpp
@@ -0,0 +1,204 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsWaylandDisplay.h"
+
+#include <dlfcn.h>
+
+#include "base/message_loop.h"    // for MessageLoop
+#include "base/task.h"            // for NewRunnableMethod, etc
+#include "mozilla/gfx/Logging.h"  // for gfxCriticalNote
+#include "mozilla/StaticMutex.h"
+#include "mozilla/Array.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/ThreadLocal.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/Sprintf.h"
+#include "WidgetUtilsGtk.h"
+#include "nsGtkKeyUtils.h"
+
+namespace mozilla::widget {
+
+static nsWaylandDisplay* gWaylandDisplay;
+
+void WaylandDisplayRelease() {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread(),
+                     "WaylandDisplay can be released in main thread only!");
+  if (!gWaylandDisplay) {
+    NS_WARNING("WaylandDisplayRelease(): Wayland display is missing!");
+    return;
+  }
+  delete gWaylandDisplay;
+  gWaylandDisplay = nullptr;
+}
+
+wl_display* WaylandDisplayGetWLDisplay() {
+  GdkDisplay* disp = gdk_display_get_default();
+  if (!GdkIsWaylandDisplay(disp)) {
+    return nullptr;
+  }
+  return gdk_wayland_display_get_wl_display(disp);
+}
+
+nsWaylandDisplay* WaylandDisplayGet() {
+  if (!gWaylandDisplay) {
+    MOZ_RELEASE_ASSERT(NS_IsMainThread(),
+                       "WaylandDisplay can be created in main thread only!");
+    wl_display* waylandDisplay = WaylandDisplayGetWLDisplay();
+    if (!waylandDisplay) {
+      return nullptr;
+    }
+    gWaylandDisplay = new nsWaylandDisplay(waylandDisplay);
+  }
+  return gWaylandDisplay;
+}
+
+void nsWaylandDisplay::SetShm(wl_shm* aShm) { mShm = aShm; }
+
+void nsWaylandDisplay::SetCompositor(wl_compositor* aCompositor) {
+  mCompositor = aCompositor;
+}
+
+void nsWaylandDisplay::SetSubcompositor(wl_subcompositor* aSubcompositor) {
+  mSubcompositor = aSubcompositor;
+}
+
+void nsWaylandDisplay::SetIdleInhibitManager(
+    zwp_idle_inhibit_manager_v1* aIdleInhibitManager) {
+  mIdleInhibitManager = aIdleInhibitManager;
+}
+
+void nsWaylandDisplay::SetViewporter(wp_viewporter* aViewporter) {
+  mViewporter = aViewporter;
+}
+
+void nsWaylandDisplay::SetRelativePointerManager(
+    zwp_relative_pointer_manager_v1* aRelativePointerManager) {
+  mRelativePointerManager = aRelativePointerManager;
+}
+
+void nsWaylandDisplay::SetPointerConstraints(
+    zwp_pointer_constraints_v1* aPointerConstraints) {
+  mPointerConstraints = aPointerConstraints;
+}
+
+void nsWaylandDisplay::SetDmabuf(zwp_linux_dmabuf_v1* aDmabuf) {
+  mDmabuf = aDmabuf;
+}
+
+void nsWaylandDisplay::SetXdgActivation(xdg_activation_v1* aXdgActivation) {
+  mXdgActivation = aXdgActivation;
+}
+
+static void global_registry_handler(void* data, wl_registry* registry,
+                                    uint32_t id, const char* interface,
+                                    uint32_t version) {
+  auto* display = static_cast<nsWaylandDisplay*>(data);
+  if (!display) {
+    return;
+  }
+
+  nsDependentCString iface(interface);
+  if (iface.EqualsLiteral("wl_shm")) {
+    auto* shm = WaylandRegistryBind<wl_shm>(registry, id, &wl_shm_interface, 1);
+    display->SetShm(shm);
+  } else if (iface.EqualsLiteral("zwp_idle_inhibit_manager_v1")) {
+    auto* idle_inhibit_manager =
+        WaylandRegistryBind<zwp_idle_inhibit_manager_v1>(
+            registry, id, &zwp_idle_inhibit_manager_v1_interface, 1);
+    display->SetIdleInhibitManager(idle_inhibit_manager);
+  } else if (iface.EqualsLiteral("zwp_relative_pointer_manager_v1")) {
+    auto* relative_pointer_manager =
+        WaylandRegistryBind<zwp_relative_pointer_manager_v1>(
+            registry, id, &zwp_relative_pointer_manager_v1_interface, 1);
+    display->SetRelativePointerManager(relative_pointer_manager);
+  } else if (iface.EqualsLiteral("zwp_pointer_constraints_v1")) {
+    auto* pointer_constraints = WaylandRegistryBind<zwp_pointer_constraints_v1>(
+        registry, id, &zwp_pointer_constraints_v1_interface, 1);
+    display->SetPointerConstraints(pointer_constraints);
+  } else if (iface.EqualsLiteral("wl_compositor")) {
+    // Requested wl_compositor version 4 as we need wl_surface_damage_buffer().
+    auto* compositor = WaylandRegistryBind<wl_compositor>(
+        registry, id, &wl_compositor_interface, 4);
+    display->SetCompositor(compositor);
+  } else if (iface.EqualsLiteral("wl_subcompositor")) {
+    auto* subcompositor = WaylandRegistryBind<wl_subcompositor>(
+        registry, id, &wl_subcompositor_interface, 1);
+    display->SetSubcompositor(subcompositor);
+  } else if (iface.EqualsLiteral("wp_viewporter")) {
+    auto* viewporter = WaylandRegistryBind<wp_viewporter>(
+        registry, id, &wp_viewporter_interface, 1);
+    display->SetViewporter(viewporter);
+  } else if (iface.EqualsLiteral("zwp_linux_dmabuf_v1") && version > 2) {
+    auto* dmabuf = WaylandRegistryBind<zwp_linux_dmabuf_v1>(
+        registry, id, &zwp_linux_dmabuf_v1_interface, 3);
+    display->SetDmabuf(dmabuf);
+  } else if (iface.EqualsLiteral("xdg_activation_v1")) {
+    auto* activation = WaylandRegistryBind<xdg_activation_v1>(
+        registry, id, &xdg_activation_v1_interface, 1);
+    display->SetXdgActivation(activation);
+  } else if (iface.EqualsLiteral("wl_seat")) {
+    // Install keyboard handlers for main thread only
+    auto* seat =
+        WaylandRegistryBind<wl_seat>(registry, id, &wl_seat_interface, 1);
+    KeymapWrapper::SetSeat(seat, id);
+  } else if (iface.EqualsLiteral("wp_fractional_scale_manager_v1")) {
+    auto* manager = WaylandRegistryBind<wp_fractional_scale_manager_v1>(
+        registry, id, &wp_fractional_scale_manager_v1_interface, 1);
+    display->SetFractionalScaleManager(manager);
+  } else if (iface.EqualsLiteral("gtk_primary_selection_device_manager") ||
+             iface.EqualsLiteral("zwp_primary_selection_device_manager_v1")) {
+    display->EnablePrimarySelection();
+  }
+}
+
+static void global_registry_remover(void* data, wl_registry* registry,
+                                    uint32_t id) {
+  KeymapWrapper::ClearSeat(id);
+}
+
+static const struct wl_registry_listener registry_listener = {
+    global_registry_handler, global_registry_remover};
+
+nsWaylandDisplay::~nsWaylandDisplay() {}
+
+static void WlLogHandler(const char* format, va_list args) {
+  char error[1000];
+  VsprintfLiteral(error, format, args);
+  gfxCriticalNote << "Wayland protocol error: " << error;
+
+  // See Bug 1826583 and Bug 1844653 for reference.
+  // "warning: queue %p destroyed while proxies still attached" and variants
+  // like "zwp_linux_dmabuf_feedback_v1@%d still attached" are exceptions on
+  // Wayland and non-fatal. They are triggered in certain versions of Mesa or
+  // the proprietary Nvidia driver and we don't want to crash because of them.
+  if (strstr(error, "still attached")) {
+    return;
+  }
+
+  MOZ_CRASH_UNSAFE(error);
+}
+
+nsWaylandDisplay::nsWaylandDisplay(wl_display* aDisplay)
+    : mThreadId(PR_GetCurrentThread()), mDisplay(aDisplay) {
+  // GTK sets the log handler on display creation, thus we overwrite it here
+  // in a similar fashion
+  wl_log_set_handler_client(WlLogHandler);
+
+  mRegistry = wl_display_get_registry(mDisplay);
+  wl_registry_add_listener(mRegistry, &registry_listener, this);
+  wl_display_roundtrip(mDisplay);
+  wl_display_roundtrip(mDisplay);
+
+  // Check we have critical Wayland interfaces.
+  // Missing ones indicates a compositor bug and we can't continue.
+  MOZ_DIAGNOSTIC_ASSERT(GetShm(), "We're missing shm interface!");
+  MOZ_DIAGNOSTIC_ASSERT(GetCompositor(), "We're missing compositor interface!");
+  MOZ_DIAGNOSTIC_ASSERT(GetSubcompositor(),
+                        "We're missing subcompositor interface!");
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/gtk/nsWaylandDisplay.h b/widget/gtk/nsWaylandDisplay.h
new file mode 100644
index 0000000000..cd8124d97f
--- /dev/null
+++ b/widget/gtk/nsWaylandDisplay.h
@@ -0,0 +1,120 @@
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __MOZ_WAYLAND_DISPLAY_H__
+#define __MOZ_WAYLAND_DISPLAY_H__
+
+#include "DMABufLibWrapper.h"
+
+#include "mozilla/widget/mozwayland.h"
+#include "mozilla/widget/gbm.h"
+#include "mozilla/widget/fractional-scale-v1-client-protocol.h"
+#include "mozilla/widget/idle-inhibit-unstable-v1-client-protocol.h"
+#include "mozilla/widget/relative-pointer-unstable-v1-client-protocol.h"
+#include "mozilla/widget/pointer-constraints-unstable-v1-client-protocol.h"
+#include "mozilla/widget/linux-dmabuf-unstable-v1-client-protocol.h"
+#include "mozilla/widget/viewporter-client-protocol.h"
+#include "mozilla/widget/xdg-activation-v1-client-protocol.h"
+#include "mozilla/widget/xdg-output-unstable-v1-client-protocol.h"
+
+namespace mozilla::widget {
+
+// Our general connection to Wayland display server,
+// holds our display connection and runs event loop.
+// We have a global nsWaylandDisplay object for each thread.
+class nsWaylandDisplay {
+ public:
+  // Create nsWaylandDisplay object on top of native Wayland wl_display
+  // connection.
+  explicit nsWaylandDisplay(wl_display* aDisplay);
+
+  wl_display* GetDisplay() { return mDisplay; };
+  wl_compositor* GetCompositor() { return mCompositor; };
+  wl_subcompositor* GetSubcompositor() { return mSubcompositor; };
+  wl_shm* GetShm() { return mShm; };
+  zwp_idle_inhibit_manager_v1* GetIdleInhibitManager() {
+    return mIdleInhibitManager;
+  }
+  wp_viewporter* GetViewporter() { return mViewporter; };
+  zwp_relative_pointer_manager_v1* GetRelativePointerManager() {
+    return mRelativePointerManager;
+  }
+  zwp_pointer_constraints_v1* GetPointerConstraints() {
+    return mPointerConstraints;
+  }
+  zwp_linux_dmabuf_v1* GetDmabuf() { return mDmabuf; };
+  xdg_activation_v1* GetXdgActivation() { return mXdgActivation; };
+  wp_fractional_scale_manager_v1* GetFractionalScaleManager() {
+    return mFractionalScaleManager;
+  }
+  bool IsPrimarySelectionEnabled() { return mIsPrimarySelectionEnabled; }
+
+  void SetShm(wl_shm* aShm);
+  void SetCompositor(wl_compositor* aCompositor);
+  void SetSubcompositor(wl_subcompositor* aSubcompositor);
+  void SetDataDeviceManager(wl_data_device_manager* aDataDeviceManager);
+  void SetIdleInhibitManager(zwp_idle_inhibit_manager_v1* aIdleInhibitManager);
+  void SetViewporter(wp_viewporter* aViewporter);
+  void SetRelativePointerManager(
+      zwp_relative_pointer_manager_v1* aRelativePointerManager);
+  void SetPointerConstraints(zwp_pointer_constraints_v1* aPointerConstraints);
+  void SetDmabuf(zwp_linux_dmabuf_v1* aDmabuf);
+  void SetXdgActivation(xdg_activation_v1* aXdgActivation);
+  void SetFractionalScaleManager(wp_fractional_scale_manager_v1* aManager) {
+    mFractionalScaleManager = aManager;
+  }
+  void EnablePrimarySelection() { mIsPrimarySelectionEnabled = true; }
+
+  ~nsWaylandDisplay();
+
+ private:
+  PRThread* mThreadId = nullptr;
+  wl_registry* mRegistry = nullptr;
+  wl_display* mDisplay = nullptr;
+  wl_compositor* mCompositor = nullptr;
+  wl_subcompositor* mSubcompositor = nullptr;
+  wl_shm* mShm = nullptr;
+  zwp_idle_inhibit_manager_v1* mIdleInhibitManager = nullptr;
+  zwp_relative_pointer_manager_v1* mRelativePointerManager = nullptr;
+  zwp_pointer_constraints_v1* mPointerConstraints = nullptr;
+  wp_viewporter* mViewporter = nullptr;
+  zwp_linux_dmabuf_v1* mDmabuf = nullptr;
+  xdg_activation_v1* mXdgActivation = nullptr;
+  wp_fractional_scale_manager_v1* mFractionalScaleManager = nullptr;
+  bool mExplicitSync = false;
+  bool mIsPrimarySelectionEnabled = false;
+};
+
+wl_display* WaylandDisplayGetWLDisplay();
+nsWaylandDisplay* WaylandDisplayGet();
+void WaylandDisplayRelease();
+
+}  // namespace mozilla::widget
+
+template <class T>
+static inline T* WaylandRegistryBind(struct wl_registry* wl_registry,
+                                     uint32_t name,
+                                     const struct wl_interface* interface,
+                                     uint32_t version) {
+  struct wl_proxy* id;
+
+  // When libwayland-client does not provide this symbol, it will be
+  // linked to the fallback in libmozwayland, which returns NULL.
+  id = wl_proxy_marshal_constructor_versioned(
+      (struct wl_proxy*)wl_registry, WL_REGISTRY_BIND, interface, version, name,
+      interface->name, version, nullptr);
+
+  if (id == nullptr) {
+    id = wl_proxy_marshal_constructor((struct wl_proxy*)wl_registry,
+                                      WL_REGISTRY_BIND, interface, name,
+                                      interface->name, version, nullptr);
+  }
+
+  return reinterpret_cast<T*>(id);
+}
+
+#endif  // __MOZ_WAYLAND_DISPLAY_H__
diff --git a/widget/gtk/nsWidgetFactory.cpp b/widget/gtk/nsWidgetFactory.cpp
new file mode 100644
index 0000000000..7f06e8f9f3
--- /dev/null
+++ b/widget/gtk/nsWidgetFactory.cpp
@@ -0,0 +1,67 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsWidgetFactory.h"
+
+#include "mozilla/Components.h"
+#include "mozilla/WidgetUtils.h"
+#include "NativeKeyBindings.h"
+#include "nsWidgetsCID.h"
+#include "nsAppShell.h"
+#include "nsAppShellSingleton.h"
+#include "nsBaseWidget.h"
+#include "nsGtkKeyUtils.h"
+#include "nsLookAndFeel.h"
+#include "nsWindow.h"
+#include "nsHTMLFormatConverter.h"
+#include "HeadlessClipboard.h"
+#include "IMContextWrapper.h"
+#include "nsClipboard.h"
+#include "TaskbarProgress.h"
+#include "nsFilePicker.h"
+#include "nsSound.h"
+#include "nsGTKToolkit.h"
+#include "WakeLockListener.h"
+
+#include "mozilla/gfx/2D.h"
+#include "mozilla/widget/ScreenManager.h"
+#include <gtk/gtk.h>
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+NS_IMPL_COMPONENT_FACTORY(nsIClipboard) {
+  nsCOMPtr<nsIClipboard> inst;
+  if (gfxPlatform::IsHeadless()) {
+    inst = new HeadlessClipboard();
+  } else {
+    auto clipboard = MakeRefPtr<nsClipboard>();
+    if (NS_FAILED(clipboard->Init())) {
+      return nullptr;
+    }
+    inst = std::move(clipboard);
+  }
+
+  return inst.forget().downcast<nsISupports>();
+}
+
+nsresult nsWidgetGtk2ModuleCtor() { return nsAppShellInit(); }
+
+void nsWidgetGtk2ModuleDtor() {
+  // Shutdown all XP level widget classes.
+  WidgetUtils::Shutdown();
+
+  NativeKeyBindings::Shutdown();
+  nsLookAndFeel::Shutdown();
+  nsFilePicker::Shutdown();
+  nsSound::Shutdown();
+  nsWindow::ReleaseGlobals();
+  IMContextWrapper::Shutdown();
+  KeymapWrapper::Shutdown();
+  nsGTKToolkit::Shutdown();
+  nsAppShellShutdown();
+}
diff --git a/widget/gtk/nsWidgetFactory.h b/widget/gtk/nsWidgetFactory.h
new file mode 100644
index 0000000000..f9312f6274
--- /dev/null
+++ b/widget/gtk/nsWidgetFactory.h
@@ -0,0 +1,21 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_gtk_nsWidgetFactory_h
+#define widget_gtk_nsWidgetFactory_h
+
+#include "nscore.h"
+#include "nsID.h"
+
+class nsISupports;
+
+nsresult nsAppShellConstructor(const nsIID& iid, void** result);
+
+nsresult nsWidgetGtk2ModuleCtor();
+void nsWidgetGtk2ModuleDtor();
+
+#endif  // defined widget_gtk_nsWidgetFactory_h
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
new file mode 100644
index 0000000000..8185c7bda9
--- /dev/null
+++ b/widget/gtk/nsWindow.cpp
@@ -0,0 +1,10028 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsWindow.h"
+
+#include <algorithm>
+#include <cstdint>
+#include <dlfcn.h>
+#include <gdk/gdkkeysyms.h>
+#include <wchar.h>
+
+#include "VsyncSource.h"
+#include "gfx2DGlue.h"
+#include "gfxContext.h"
+#include "gfxImageSurface.h"
+#include "gfxPlatformGtk.h"
+#include "gfxUtils.h"
+#include "GLContextProvider.h"
+#include "GLContext.h"
+#include "GtkCompositorWidget.h"
+#include "gtkdrawing.h"
+#include "imgIContainer.h"
+#include "InputData.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Components.h"
+#include "mozilla/GRefPtr.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/WheelEventBinding.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/gfx/GPUProcessManager.h"
+#include "mozilla/gfx/HelpersCairo.h"
+#include "mozilla/layers/APZThreadUtils.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+#include "mozilla/layers/CompositorThread.h"
+#include "mozilla/layers/KnowsCompositor.h"
+#include "mozilla/layers/WebRenderBridgeChild.h"
+#include "mozilla/layers/WebRenderLayerManager.h"
+#include "mozilla/layers/APZInputBridge.h"
+#include "mozilla/layers/IAPZCTreeManager.h"
+#include "mozilla/Likely.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPrefs_apz.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/StaticPrefs_mozilla.h"
+#include "mozilla/StaticPrefs_ui.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/SwipeTracker.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "mozilla/WidgetUtils.h"
+#include "mozilla/WritingModes.h"
+#ifdef MOZ_X11
+#  include "mozilla/X11Util.h"
+#endif
+#include "mozilla/XREAppData.h"
+#include "NativeKeyBindings.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsAppRunner.h"
+#include "nsDragService.h"
+#include "nsGTKToolkit.h"
+#include "nsGtkKeyUtils.h"
+#include "nsGtkCursors.h"
+#include "nsGfxCIID.h"
+#include "nsGtkUtils.h"
+#include "nsIFile.h"
+#include "nsIGSettingsService.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsImageToPixbuf.h"
+#include "nsINode.h"
+#include "nsIRollupListener.h"
+#include "nsIScreenManager.h"
+#include "nsIUserIdleServiceInternal.h"
+#include "nsIWidgetListener.h"
+#include "nsLayoutUtils.h"
+#include "nsMenuPopupFrame.h"
+#include "nsPresContext.h"
+#include "nsShmImage.h"
+#include "nsString.h"
+#include "nsWidgetsCID.h"
+#include "nsViewManager.h"
+#include "nsXPLookAndFeel.h"
+#include "prlink.h"
+#include "Screen.h"
+#include "ScreenHelperGTK.h"
+#include "SystemTimeConverter.h"
+#include "WidgetUtilsGtk.h"
+
+#ifdef ACCESSIBILITY
+#  include "mozilla/a11y/LocalAccessible.h"
+#  include "mozilla/a11y/Platform.h"
+#  include "nsAccessibilityService.h"
+#endif
+
+#ifdef MOZ_X11
+#  include <gdk/gdkkeysyms-compat.h>
+#  include <X11/Xatom.h>
+#  include <X11/extensions/XShm.h>
+#  include <X11/extensions/shape.h>
+#  include "gfxXlibSurface.h"
+#  include "GLContextGLX.h"  // for GLContextGLX::FindVisual()
+#  include "GLContextEGL.h"  // for GLContextEGL::FindVisual()
+#  include "WindowSurfaceX11Image.h"
+#  include "WindowSurfaceX11SHM.h"
+#endif
+#ifdef MOZ_WAYLAND
+#  include <gdk/gdkkeysyms-compat.h>
+#  include "nsIClipboard.h"
+#  include "nsView.h"
+#endif
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using namespace mozilla::layers;
+using namespace mozilla::widget;
+#ifdef MOZ_X11
+using mozilla::gl::GLContextEGL;
+using mozilla::gl::GLContextGLX;
+#endif
+
+// Don't put more than this many rects in the dirty region, just fluff
+// out to the bounding-box if there are more
+#define MAX_RECTS_IN_REGION 100
+
+#if !GTK_CHECK_VERSION(3, 18, 0)
+
+struct _GdkEventTouchpadPinch {
+  GdkEventType type;
+  GdkWindow* window;
+  gint8 send_event;
+  gint8 phase;
+  gint8 n_fingers;
+  guint32 time;
+  gdouble x;
+  gdouble y;
+  gdouble dx;
+  gdouble dy;
+  gdouble angle_delta;
+  gdouble scale;
+  gdouble x_root, y_root;
+  guint state;
+};
+
+typedef enum {
+  GDK_TOUCHPAD_GESTURE_PHASE_BEGIN,
+  GDK_TOUCHPAD_GESTURE_PHASE_UPDATE,
+  GDK_TOUCHPAD_GESTURE_PHASE_END,
+  GDK_TOUCHPAD_GESTURE_PHASE_CANCEL
+} GdkTouchpadGesturePhase;
+
+gint GDK_TOUCHPAD_GESTURE_MASK = 1 << 24;
+GdkEventType GDK_TOUCHPAD_PINCH = static_cast<GdkEventType>(42);
+
+#endif
+
+const gint kEvents = GDK_TOUCHPAD_GESTURE_MASK | GDK_EXPOSURE_MASK |
+                     GDK_STRUCTURE_MASK | GDK_VISIBILITY_NOTIFY_MASK |
+                     GDK_ENTER_NOTIFY_MASK | GDK_LEAVE_NOTIFY_MASK |
+                     GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK |
+                     GDK_SMOOTH_SCROLL_MASK | GDK_TOUCH_MASK | GDK_SCROLL_MASK |
+                     GDK_POINTER_MOTION_MASK | GDK_PROPERTY_CHANGE_MASK;
+
+/* utility functions */
+static bool is_mouse_in_window(GdkWindow* aWindow, gdouble aMouseX,
+                               gdouble aMouseY);
+static nsWindow* get_window_for_gtk_widget(GtkWidget* widget);
+static nsWindow* get_window_for_gdk_window(GdkWindow* window);
+static GtkWidget* get_gtk_widget_for_gdk_window(GdkWindow* window);
+static GdkCursor* get_gtk_cursor(nsCursor aCursor);
+static GdkWindow* get_inner_gdk_window(GdkWindow* aWindow, gint x, gint y,
+                                       gint* retx, gint* rety);
+
+/* callbacks from widgets */
+static gboolean expose_event_cb(GtkWidget* widget, cairo_t* cr);
+static gboolean configure_event_cb(GtkWidget* widget, GdkEventConfigure* event);
+static void widget_map_cb(GtkWidget* widget);
+static void widget_unmap_cb(GtkWidget* widget);
+static void size_allocate_cb(GtkWidget* widget, GtkAllocation* allocation);
+static void toplevel_window_size_allocate_cb(GtkWidget* widget,
+                                             GtkAllocation* allocation);
+static gboolean delete_event_cb(GtkWidget* widget, GdkEventAny* event);
+static gboolean enter_notify_event_cb(GtkWidget* widget,
+                                      GdkEventCrossing* event);
+static gboolean leave_notify_event_cb(GtkWidget* widget,
+                                      GdkEventCrossing* event);
+static gboolean motion_notify_event_cb(GtkWidget* widget,
+                                       GdkEventMotion* event);
+MOZ_CAN_RUN_SCRIPT static gboolean button_press_event_cb(GtkWidget* widget,
+                                                         GdkEventButton* event);
+static gboolean button_release_event_cb(GtkWidget* widget,
+                                        GdkEventButton* event);
+static gboolean focus_in_event_cb(GtkWidget* widget, GdkEventFocus* event);
+static gboolean focus_out_event_cb(GtkWidget* widget, GdkEventFocus* event);
+static gboolean key_press_event_cb(GtkWidget* widget, GdkEventKey* event);
+static gboolean key_release_event_cb(GtkWidget* widget, GdkEventKey* event);
+static gboolean property_notify_event_cb(GtkWidget* widget,
+                                         GdkEventProperty* event);
+static gboolean scroll_event_cb(GtkWidget* widget, GdkEventScroll* event);
+static gboolean visibility_notify_event_cb(GtkWidget* widget,
+                                           GdkEventVisibility* event);
+static void hierarchy_changed_cb(GtkWidget* widget,
+                                 GtkWidget* previous_toplevel);
+static gboolean window_state_event_cb(GtkWidget* widget,
+                                      GdkEventWindowState* event);
+static void settings_xft_dpi_changed_cb(GtkSettings* settings,
+                                        GParamSpec* pspec, nsWindow* data);
+static void check_resize_cb(GtkContainer* container, gpointer user_data);
+static void screen_composited_changed_cb(GdkScreen* screen, gpointer user_data);
+static void widget_composited_changed_cb(GtkWidget* widget, gpointer user_data);
+
+static void scale_changed_cb(GtkWidget* widget, GParamSpec* aPSpec,
+                             gpointer aPointer);
+static gboolean touch_event_cb(GtkWidget* aWidget, GdkEventTouch* aEvent);
+static gboolean generic_event_cb(GtkWidget* widget, GdkEvent* aEvent);
+
+static nsWindow* GetFirstNSWindowForGDKWindow(GdkWindow* aGdkWindow);
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+#ifdef MOZ_X11
+static GdkFilterReturn popup_take_focus_filter(GdkXEvent* gdk_xevent,
+                                               GdkEvent* event, gpointer data);
+#endif /* MOZ_X11 */
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+static gboolean drag_motion_event_cb(GtkWidget* aWidget,
+                                     GdkDragContext* aDragContext, gint aX,
+                                     gint aY, guint aTime, gpointer aData);
+static void drag_leave_event_cb(GtkWidget* aWidget,
+                                GdkDragContext* aDragContext, guint aTime,
+                                gpointer aData);
+static gboolean drag_drop_event_cb(GtkWidget* aWidget,
+                                   GdkDragContext* aDragContext, gint aX,
+                                   gint aY, guint aTime, gpointer aData);
+static void drag_data_received_event_cb(GtkWidget* aWidget,
+                                        GdkDragContext* aDragContext, gint aX,
+                                        gint aY,
+                                        GtkSelectionData* aSelectionData,
+                                        guint aInfo, guint32 aTime,
+                                        gpointer aData);
+
+/* initialization static functions */
+static nsresult initialize_prefs(void);
+
+static guint32 sLastUserInputTime = GDK_CURRENT_TIME;
+
+static SystemTimeConverter<guint32>& TimeConverter() {
+  static SystemTimeConverter<guint32> sTimeConverterSingleton;
+  return sTimeConverterSingleton;
+}
+
+bool nsWindow::sTransparentMainWindow = false;
+
+// forward declare from mozgtk
+extern "C" MOZ_EXPORT void mozgtk_linker_holder();
+
+namespace mozilla {
+
+#ifdef MOZ_X11
+class CurrentX11TimeGetter {
+ public:
+  explicit CurrentX11TimeGetter(GdkWindow* aWindow) : mWindow(aWindow) {}
+
+  guint32 GetCurrentTime() const { return gdk_x11_get_server_time(mWindow); }
+
+  void GetTimeAsyncForPossibleBackwardsSkew(const TimeStamp& aNow) {
+    // Check for in-flight request
+    if (!mAsyncUpdateStart.IsNull()) {
+      return;
+    }
+    mAsyncUpdateStart = aNow;
+
+    Display* xDisplay = GDK_WINDOW_XDISPLAY(mWindow);
+    Window xWindow = GDK_WINDOW_XID(mWindow);
+    unsigned char c = 'a';
+    Atom timeStampPropAtom = TimeStampPropAtom();
+    XChangeProperty(xDisplay, xWindow, timeStampPropAtom, timeStampPropAtom, 8,
+                    PropModeReplace, &c, 1);
+    XFlush(xDisplay);
+  }
+
+  gboolean PropertyNotifyHandler(GtkWidget* aWidget, GdkEventProperty* aEvent) {
+    if (aEvent->atom != gdk_x11_xatom_to_atom(TimeStampPropAtom())) {
+      return FALSE;
+    }
+
+    guint32 eventTime = aEvent->time;
+    TimeStamp lowerBound = mAsyncUpdateStart;
+
+    TimeConverter().CompensateForBackwardsSkew(eventTime, lowerBound);
+    mAsyncUpdateStart = TimeStamp();
+    return TRUE;
+  }
+
+ private:
+  static Atom TimeStampPropAtom() {
+    return gdk_x11_get_xatom_by_name_for_display(gdk_display_get_default(),
+                                                 "GDK_TIMESTAMP_PROP");
+  }
+
+  // This is safe because this class is stored as a member of mWindow and
+  // won't outlive it.
+  GdkWindow* mWindow;
+  TimeStamp mAsyncUpdateStart;
+};
+#endif
+
+}  // namespace mozilla
+
+// The window from which the focus manager asks us to dispatch key events.
+static nsWindow* gFocusWindow = nullptr;
+static bool gBlockActivateEvent = false;
+static bool gGlobalsInitialized = false;
+static bool gUseAspectRatio = true;
+static uint32_t gLastTouchID = 0;
+// See Bug 1777269 for details. We don't know if the suspected leave notify
+// event is a correct one when we get it.
+// Store it and issue it later from enter notify event if it's correct,
+// throw it away otherwise.
+static GUniquePtr<GdkEventCrossing> sStoredLeaveNotifyEvent;
+
+#define NS_WINDOW_TITLE_MAX_LENGTH 4095
+
+// cursor cache
+static GdkCursor* gCursorCache[eCursorCount];
+
+// Sometimes this actually also includes the state of the modifier keys, but
+// only the button state bits are used.
+static guint gButtonState;
+
+static inline int32_t GetBitmapStride(int32_t width) {
+#if defined(MOZ_X11)
+  return (width + 7) / 8;
+#else
+  return cairo_format_stride_for_width(CAIRO_FORMAT_A1, width);
+#endif
+}
+
+static inline bool TimestampIsNewerThan(guint32 a, guint32 b) {
+  // Timestamps are just the least significant bits of a monotonically
+  // increasing function, and so the use of unsigned overflow arithmetic.
+  return a - b <= G_MAXUINT32 / 2;
+}
+
+static void UpdateLastInputEventTime(void* aGdkEvent) {
+  nsCOMPtr<nsIUserIdleServiceInternal> idleService =
+      do_GetService("@mozilla.org/widget/useridleservice;1");
+  if (idleService) {
+    idleService->ResetIdleTimeOut(0);
+  }
+
+  guint timestamp = gdk_event_get_time(static_cast<GdkEvent*>(aGdkEvent));
+  if (timestamp == GDK_CURRENT_TIME) {
+    return;
+  }
+
+  sLastUserInputTime = timestamp;
+}
+
+// Don't set parent (transient for) if nothing changes.
+// gtk_window_set_transient_for() blows up wl_subsurfaces used by aWindow
+// even if aParent is the same.
+static void GtkWindowSetTransientFor(GtkWindow* aWindow, GtkWindow* aParent) {
+  GtkWindow* parent = gtk_window_get_transient_for(aWindow);
+  if (parent != aParent) {
+    gtk_window_set_transient_for(aWindow, aParent);
+  }
+}
+
+#define gtk_window_set_transient_for(a, b)                         \
+  {                                                                \
+    MOZ_ASSERT_UNREACHABLE(                                        \
+        "gtk_window_set_transient_for() can't be used directly."); \
+  }
+
+nsWindow::nsWindow()
+    : mTitlebarRectMutex("nsWindow::mTitlebarRectMutex"),
+      mDestroyMutex("nsWindow::mDestroyMutex"),
+      mIsDestroyed(false),
+      mIsShown(false),
+      mNeedsShow(false),
+      mIsMapped(false),
+      mEnabled(true),
+      mCreated(false),
+      mHandleTouchEvent(false),
+      mIsDragPopup(false),
+      mCompositedScreen(gdk_screen_is_composited(gdk_screen_get_default())),
+      mIsAccelerated(false),
+      mWindowShouldStartDragging(false),
+      mHasMappedToplevel(false),
+      mRetryPointerGrab(false),
+      mPanInProgress(false),
+      mTitlebarBackdropState(false),
+      mIsChildWindow(false),
+      mAlwaysOnTop(false),
+      mNoAutoHide(false),
+      mIsTransparent(false),
+      mHasReceivedSizeAllocate(false),
+      mWidgetCursorLocked(false),
+      mUndecorated(false),
+      mPopupTrackInHierarchy(false),
+      mPopupTrackInHierarchyConfigured(false),
+      mHiddenPopupPositioned(false),
+      mTransparencyBitmapForTitlebar(false),
+      mHasAlphaVisual(false),
+      mPopupAnchored(false),
+      mPopupContextMenu(false),
+      mPopupMatchesLayout(false),
+      mPopupChanged(false),
+      mPopupTemporaryHidden(false),
+      mPopupClosed(false),
+      mPopupUseMoveToRect(false),
+      mWaitingForMoveToRectCallback(false),
+      mMovedAfterMoveToRect(false),
+      mResizedAfterMoveToRect(false),
+      mConfiguredClearColor(false),
+      mGotNonBlankPaint(false),
+      mNeedsToRetryCapturingMouse(false) {
+  mWindowType = WindowType::Child;
+  mSizeConstraints.mMaxSize = GetSafeWindowSize(mSizeConstraints.mMaxSize);
+
+  if (!gGlobalsInitialized) {
+    gGlobalsInitialized = true;
+
+    // It's OK if either of these fail, but it may not be one day.
+    initialize_prefs();
+
+#ifdef MOZ_WAYLAND
+    // Wayland provides clipboard data to application on focus-in event
+    // so we need to init our clipboard hooks before we create window
+    // and get focus.
+    if (GdkIsWaylandDisplay()) {
+      nsCOMPtr<nsIClipboard> clipboard =
+          do_GetService("@mozilla.org/widget/clipboard;1");
+      NS_ASSERTION(clipboard, "Failed to init clipboard!");
+    }
+#endif
+  }
+  // Dummy call to mozgtk to prevent the linker from removing
+  // the dependency with --as-needed.
+  // see toolkit/library/moz.build for details.
+  mozgtk_linker_holder();
+}
+
+nsWindow::~nsWindow() {
+  LOG("nsWindow::~nsWindow()");
+  Destroy();
+}
+
+/* static */
+void nsWindow::ReleaseGlobals() {
+  for (auto& cursor : gCursorCache) {
+    if (cursor) {
+      g_object_unref(cursor);
+      cursor = nullptr;
+    }
+  }
+}
+
+void nsWindow::DispatchActivateEvent(void) {
+#ifdef ACCESSIBILITY
+  DispatchActivateEventAccessible();
+#endif  // ACCESSIBILITY
+
+  if (mWidgetListener) mWidgetListener->WindowActivated();
+}
+
+void nsWindow::DispatchDeactivateEvent() {
+  if (mWidgetListener) {
+    mWidgetListener->WindowDeactivated();
+  }
+
+#ifdef ACCESSIBILITY
+  DispatchDeactivateEventAccessible();
+#endif  // ACCESSIBILITY
+}
+
+void nsWindow::DispatchResized() {
+  LOG("nsWindow::DispatchResized() size [%d, %d]", (int)(mBounds.width),
+      (int)(mBounds.height));
+
+  mNeedsDispatchSize = LayoutDeviceIntSize(-1, -1);
+  if (mWidgetListener) {
+    mWidgetListener->WindowResized(this, mBounds.width, mBounds.height);
+  }
+  if (mAttachedWidgetListener) {
+    mAttachedWidgetListener->WindowResized(this, mBounds.width, mBounds.height);
+  }
+}
+
+void nsWindow::MaybeDispatchResized() {
+  if (mNeedsDispatchSize != LayoutDeviceIntSize(-1, -1) && !mIsDestroyed) {
+    mBounds.SizeTo(mNeedsDispatchSize);
+    // Check mBounds size
+    if (mCompositorSession &&
+        !wr::WindowSizeSanityCheck(mBounds.width, mBounds.height)) {
+      gfxCriticalNoteOnce << "Invalid mBounds in MaybeDispatchResized "
+                          << mBounds << " size state " << mSizeMode;
+    }
+
+    if (IsTopLevelWindowType()) {
+      UpdateTopLevelOpaqueRegion();
+    }
+
+    // Notify the GtkCompositorWidget of a ClientSizeChange
+    if (mCompositorWidgetDelegate) {
+      mCompositorWidgetDelegate->NotifyClientSizeChanged(GetClientSize());
+    }
+
+    DispatchResized();
+  }
+}
+
+nsIWidgetListener* nsWindow::GetListener() {
+  return mAttachedWidgetListener ? mAttachedWidgetListener : mWidgetListener;
+}
+
+nsresult nsWindow::DispatchEvent(WidgetGUIEvent* aEvent,
+                                 nsEventStatus& aStatus) {
+#ifdef DEBUG
+  debug_DumpEvent(stdout, aEvent->mWidget, aEvent, "something", 0);
+#endif
+  aStatus = nsEventStatus_eIgnore;
+  nsIWidgetListener* listener = GetListener();
+  if (listener) {
+    aStatus = listener->HandleEvent(aEvent, mUseAttachedEvents);
+  }
+
+  return NS_OK;
+}
+
+void nsWindow::OnDestroy(void) {
+  if (mOnDestroyCalled) {
+    return;
+  }
+
+  mOnDestroyCalled = true;
+
+  // Prevent deletion.
+  nsCOMPtr<nsIWidget> kungFuDeathGrip = this;
+
+  // release references to children, device context, toolkit + app shell
+  nsBaseWidget::OnDestroy();
+
+  // Remove association between this object and its parent and siblings.
+  nsBaseWidget::Destroy();
+  mParent = nullptr;
+
+  NotifyWindowDestroyed();
+}
+
+bool nsWindow::AreBoundsSane() {
+  // Check requested size, as mBounds might not have been updated.
+  return !mLastSizeRequest.IsEmpty();
+}
+
+// Walk the list of child windows and call destroy on them.
+void nsWindow::DestroyChildWindows() {
+  LOG("nsWindow::DestroyChildWindows()");
+  if (!mGdkWindow) {
+    return;
+  }
+  while (GList* children = gdk_window_peek_children(mGdkWindow)) {
+    GdkWindow* child = GDK_WINDOW(children->data);
+    nsWindow* kid = get_window_for_gdk_window(child);
+    if (kid) {
+      kid->Destroy();
+    }
+  }
+}
+
+void nsWindow::Destroy() {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+
+  if (mIsDestroyed || !mCreated) {
+    return;
+  }
+
+  LOG("nsWindow::Destroy\n");
+
+  MutexAutoLock lock(mDestroyMutex);
+  mIsDestroyed = true;
+  mCreated = false;
+
+  MozClearHandleID(mCompositorPauseTimeoutID, g_source_remove);
+
+#ifdef MOZ_WAYLAND
+  // Shut down our local vsync source
+  if (mWaylandVsyncSource) {
+    mWaylandVsyncSource->Shutdown();
+    mWaylandVsyncSource = nullptr;
+  }
+  mWaylandVsyncDispatcher = nullptr;
+#endif
+
+  // dragService will be null after shutdown of the service manager.
+  RefPtr<nsDragService> dragService = nsDragService::GetInstance();
+  if (dragService && this == dragService->GetMostRecentDestWindow()) {
+    dragService->ScheduleLeaveEvent();
+  }
+
+  nsIRollupListener* rollupListener = nsBaseWidget::GetActiveRollupListener();
+  if (rollupListener) {
+    nsCOMPtr<nsIWidget> rollupWidget = rollupListener->GetRollupWidget();
+    if (static_cast<nsIWidget*>(this) == rollupWidget) {
+      rollupListener->Rollup({});
+    }
+  }
+
+  NativeShow(false);
+
+  ClearTransparencyBitmap();
+
+  DestroyLayerManager();
+
+  // mSurfaceProvider holds reference to this nsWindow so we need to explicitly
+  // clear it here to avoid nsWindow leak.
+  mSurfaceProvider.CleanupResources();
+
+  g_signal_handlers_disconnect_by_data(gtk_settings_get_default(), this);
+
+  if (mIMContext) {
+    mIMContext->OnDestroyWindow(this);
+  }
+
+  // make sure that we remove ourself as the focus window
+  if (gFocusWindow == this) {
+    LOG("automatically losing focus...\n");
+    gFocusWindow = nullptr;
+  }
+
+  if (sStoredLeaveNotifyEvent) {
+    nsWindow* window =
+        get_window_for_gdk_window(sStoredLeaveNotifyEvent->window);
+    if (window == this) {
+      sStoredLeaveNotifyEvent = nullptr;
+    }
+  }
+
+  // We need to detach accessible object here because mContainer is a custom
+  // widget and doesn't call gtk_widget_real_destroy() from destroy handler
+  // as regular widgets.
+  if (AtkObject* ac = gtk_widget_get_accessible(GTK_WIDGET(mContainer))) {
+    gtk_accessible_set_widget(GTK_ACCESSIBLE(ac), nullptr);
+  }
+
+  gtk_widget_destroy(mShell);
+  mShell = nullptr;
+  mContainer = nullptr;
+
+  MOZ_ASSERT(!mGdkWindow,
+             "mGdkWindow should be NULL when mContainer is destroyed");
+
+#ifdef ACCESSIBILITY
+  if (mRootAccessible) {
+    mRootAccessible = nullptr;
+  }
+#endif
+
+  // Save until last because OnDestroy() may cause us to be deleted.
+  OnDestroy();
+}
+
+nsIWidget* nsWindow::GetParent() { return mParent; }
+
+float nsWindow::GetDPI() {
+  float dpi = 96.0f;
+  nsCOMPtr<nsIScreen> screen = GetWidgetScreen();
+  if (screen) {
+    screen->GetDpi(&dpi);
+  }
+  return dpi;
+}
+
+double nsWindow::GetDefaultScaleInternal() { return FractionalScaleFactor(); }
+
+DesktopToLayoutDeviceScale nsWindow::GetDesktopToDeviceScale() {
+#ifdef MOZ_WAYLAND
+  if (GdkIsWaylandDisplay()) {
+    return DesktopToLayoutDeviceScale(FractionalScaleFactor());
+  }
+#endif
+
+  // In Gtk/X11, we manage windows using device pixels.
+  return DesktopToLayoutDeviceScale(1.0);
+}
+
+DesktopToLayoutDeviceScale nsWindow::GetDesktopToDeviceScaleByScreen() {
+#ifdef MOZ_WAYLAND
+  // In Wayland there's no way to get absolute position of the window and use it
+  // to determine the screen factor of the monitor on which the window is
+  // placed. The window is notified of the current scale factor but not at this
+  // point, so the GdkScaleFactor can return wrong value which can lead to wrong
+  // popup placement. We need to use parent's window scale factor for the new
+  // one.
+  if (GdkIsWaylandDisplay()) {
+    nsView* view = nsView::GetViewFor(this);
+    if (view) {
+      nsView* parentView = view->GetParent();
+      if (parentView) {
+        nsIWidget* parentWidget = parentView->GetNearestWidget(nullptr);
+        if (parentWidget) {
+          return DesktopToLayoutDeviceScale(
+              parentWidget->RoundsWidgetCoordinatesTo());
+        }
+        NS_WARNING("Widget has no parent");
+      }
+    } else {
+      NS_WARNING("Cannot find widget view");
+    }
+  }
+#endif
+  return nsBaseWidget::GetDesktopToDeviceScale();
+}
+
+// Reparent a child window to a new parent.
+void nsWindow::SetParent(nsIWidget* aNewParent) {
+  LOG("nsWindow::SetParent() new parent %p", aNewParent);
+  if (!mIsChildWindow) {
+    NS_WARNING("Used by child widgets only");
+    return;
+  }
+
+  nsCOMPtr<nsIWidget> kungFuDeathGrip = this;
+  if (mParent) {
+    mParent->RemoveChild(this);
+  }
+  mParent = aNewParent;
+
+  // We're already deleted, quit.
+  if (!mGdkWindow || mIsDestroyed || !aNewParent) {
+    return;
+  }
+  aNewParent->AddChild(this);
+
+  auto* newParent = static_cast<nsWindow*>(aNewParent);
+
+  // New parent is deleted, quit.
+  if (newParent->mIsDestroyed) {
+    Destroy();
+    return;
+  }
+
+  GdkWindow* window = GetToplevelGdkWindow();
+  GdkWindow* parentWindow = newParent->GetToplevelGdkWindow();
+  LOG("  child GdkWindow %p set parent GdkWindow %p", window, parentWindow);
+  gdk_window_reparent(window, parentWindow, 0, 0);
+  SetHasMappedToplevel(newParent && newParent->mHasMappedToplevel);
+}
+
+bool nsWindow::WidgetTypeSupportsAcceleration() {
+  if (mWindowType == WindowType::Invisible) {
+    return false;
+  }
+
+  if (IsSmallPopup()) {
+    return false;
+  }
+  // Workaround for Bug 1479135
+  // We draw transparent popups on non-compositing screens by SW as we don't
+  // implement X shape masks in WebRender.
+  if (mWindowType == WindowType::Popup) {
+    return HasRemoteContent() && mCompositedScreen;
+  }
+
+  return true;
+}
+
+void nsWindow::ReparentNativeWidget(nsIWidget* aNewParent) {
+  MOZ_ASSERT(aNewParent, "null widget");
+  MOZ_ASSERT(!mIsDestroyed, "");
+  MOZ_ASSERT(!static_cast<nsWindow*>(aNewParent)->mIsDestroyed, "");
+  MOZ_ASSERT(
+      !mParent,
+      "nsWindow::ReparentNativeWidget() works on toplevel windows only.");
+
+  auto* newParent = static_cast<nsWindow*>(aNewParent);
+  GtkWindow* newParentWidget = GTK_WINDOW(newParent->GetGtkWidget());
+
+  LOG("nsWindow::ReparentNativeWidget new parent %p\n", newParent);
+  GtkWindowSetTransientFor(GTK_WINDOW(mShell), newParentWidget);
+}
+
+void nsWindow::SetModal(bool aModal) {
+  LOG("nsWindow::SetModal %d\n", aModal);
+  if (mIsDestroyed) {
+    return;
+  }
+
+  gtk_window_set_modal(GTK_WINDOW(mShell), aModal ? TRUE : FALSE);
+}
+
+// nsIWidget method, which means IsShown.
+bool nsWindow::IsVisible() const { return mIsShown; }
+
+bool nsWindow::IsMapped() const { return mIsMapped; }
+
+void nsWindow::RegisterTouchWindow() {
+  mHandleTouchEvent = true;
+  mTouches.Clear();
+}
+
+LayoutDeviceIntPoint nsWindow::GetScreenEdgeSlop() {
+  if (DrawsToCSDTitlebar()) {
+    return GetClientOffset();
+  }
+  return {};
+}
+
+void nsWindow::ConstrainPosition(DesktopIntPoint& aPoint) {
+  if (!mShell || GdkIsWaylandDisplay()) {
+    return;
+  }
+
+  double dpiScale = GetDefaultScale().scale;
+
+  // we need to use the window size in logical screen pixels
+  int32_t logWidth = std::max(NSToIntRound(mBounds.width / dpiScale), 1);
+  int32_t logHeight = std::max(NSToIntRound(mBounds.height / dpiScale), 1);
+
+  /* get our playing field. use the current screen, or failing that
+    for any reason, use device caps for the default screen. */
+  nsCOMPtr<nsIScreenManager> screenmgr =
+      do_GetService("@mozilla.org/gfx/screenmanager;1");
+  if (!screenmgr) {
+    return;
+  }
+  nsCOMPtr<nsIScreen> screen;
+  screenmgr->ScreenForRect(aPoint.x, aPoint.y, logWidth, logHeight,
+                           getter_AddRefs(screen));
+  // We don't have any screen so leave the coordinates as is
+  if (!screen) {
+    return;
+  }
+
+  // For normalized windows, use the desktop work area.
+  // For full screen windows, use the desktop.
+  DesktopIntRect screenRect = mSizeMode == nsSizeMode_Fullscreen
+                                  ? screen->GetRectDisplayPix()
+                                  : screen->GetAvailRectDisplayPix();
+
+  // Expand for the decoration size if needed.
+  auto slop =
+      DesktopIntPoint::Round(GetScreenEdgeSlop() / GetDesktopToDeviceScale());
+  screenRect.Inflate(slop.x, slop.y);
+
+  if (aPoint.x < screenRect.x) {
+    aPoint.x = screenRect.x;
+  } else if (aPoint.x >= screenRect.XMost() - logWidth) {
+    aPoint.x = screenRect.XMost() - logWidth;
+  }
+
+  if (aPoint.y < screenRect.y) {
+    aPoint.y = screenRect.y;
+  } else if (aPoint.y >= screenRect.YMost() - logHeight) {
+    aPoint.y = screenRect.YMost() - logHeight;
+  }
+}
+
+void nsWindow::SetSizeConstraints(const SizeConstraints& aConstraints) {
+  mSizeConstraints.mMinSize = GetSafeWindowSize(aConstraints.mMinSize);
+  mSizeConstraints.mMaxSize = GetSafeWindowSize(aConstraints.mMaxSize);
+
+  ApplySizeConstraints();
+}
+
+bool nsWindow::DrawsToCSDTitlebar() const {
+  return mSizeMode == nsSizeMode_Normal &&
+         mGtkWindowDecoration == GTK_DECORATION_CLIENT && mDrawInTitlebar;
+}
+
+void nsWindow::AddCSDDecorationSize(int* aWidth, int* aHeight) {
+  if (mSizeMode != nsSizeMode_Normal || mUndecorated ||
+      mGtkWindowDecoration != GTK_DECORATION_CLIENT || !GdkIsWaylandDisplay() ||
+      !IsGnomeDesktopEnvironment()) {
+    return;
+  }
+
+  GtkBorder decorationSize = GetCSDDecorationSize(IsPopup());
+  *aWidth += decorationSize.left + decorationSize.right;
+  *aHeight += decorationSize.top + decorationSize.bottom;
+}
+
+#ifdef MOZ_WAYLAND
+bool nsWindow::GetCSDDecorationOffset(int* aDx, int* aDy) {
+  if (!DrawsToCSDTitlebar()) {
+    return false;
+  }
+  GtkBorder decorationSize = GetCSDDecorationSize(IsPopup());
+  *aDx = decorationSize.left;
+  *aDy = decorationSize.top;
+  return true;
+}
+#endif
+
+void nsWindow::ApplySizeConstraints() {
+  if (mShell) {
+    GdkGeometry geometry;
+    geometry.min_width =
+        DevicePixelsToGdkCoordRoundUp(mSizeConstraints.mMinSize.width);
+    geometry.min_height =
+        DevicePixelsToGdkCoordRoundUp(mSizeConstraints.mMinSize.height);
+    geometry.max_width =
+        DevicePixelsToGdkCoordRoundDown(mSizeConstraints.mMaxSize.width);
+    geometry.max_height =
+        DevicePixelsToGdkCoordRoundDown(mSizeConstraints.mMaxSize.height);
+
+    uint32_t hints = 0;
+    if (mSizeConstraints.mMinSize != LayoutDeviceIntSize()) {
+      if (GdkIsWaylandDisplay()) {
+        gtk_widget_set_size_request(GTK_WIDGET(mContainer), geometry.min_width,
+                                    geometry.min_height);
+      }
+      AddCSDDecorationSize(&geometry.min_width, &geometry.min_height);
+      hints |= GDK_HINT_MIN_SIZE;
+    }
+    if (mSizeConstraints.mMaxSize !=
+        LayoutDeviceIntSize(NS_MAXSIZE, NS_MAXSIZE)) {
+      AddCSDDecorationSize(&geometry.max_width, &geometry.max_height);
+      hints |= GDK_HINT_MAX_SIZE;
+    }
+
+    if (mAspectRatio != 0.0f && !mAspectResizer) {
+      geometry.min_aspect = mAspectRatio;
+      geometry.max_aspect = mAspectRatio;
+      hints |= GDK_HINT_ASPECT;
+    }
+
+    gtk_window_set_geometry_hints(GTK_WINDOW(mShell), nullptr, &geometry,
+                                  GdkWindowHints(hints));
+  }
+}
+
+void nsWindow::Show(bool aState) {
+  if (aState == mIsShown) {
+    return;
+  }
+
+  mIsShown = aState;
+
+#ifdef MOZ_LOGGING
+  LOG("nsWindow::Show state %d frame %s\n", aState, GetFrameTag().get());
+  if (!aState && mSourceDragContext && GdkIsWaylandDisplay()) {
+    LOG("  closing Drag&Drop source window, D&D will be canceled!");
+  }
+#endif
+
+  // Ok, someone called show on a window that isn't sized to a sane
+  // value.  Mark this window as needing to have Show() called on it
+  // and return.
+  if ((aState && !AreBoundsSane()) || !mCreated) {
+    LOG("\tbounds are insane or window hasn't been created yet\n");
+    mNeedsShow = true;
+    return;
+  }
+
+  // If someone is hiding this widget, clear any needing show flag.
+  if (!aState) mNeedsShow = false;
+
+#ifdef ACCESSIBILITY
+  if (aState && a11y::ShouldA11yBeEnabled()) CreateRootAccessible();
+#endif
+
+  NativeShow(aState);
+  RefreshWindowClass();
+}
+
+void nsWindow::ResizeInt(const Maybe<LayoutDeviceIntPoint>& aMove,
+                         LayoutDeviceIntSize aSize) {
+  LOG("nsWindow::ResizeInt w:%d h:%d\n", aSize.width, aSize.height);
+  const bool moved = aMove && *aMove != mBounds.TopLeft();
+  if (moved) {
+    mBounds.MoveTo(*aMove);
+    LOG("  with move to left:%d top:%d", aMove->x.value, aMove->y.value);
+  }
+
+  ConstrainSize(&aSize.width, &aSize.height);
+  LOG("  ConstrainSize: w:%d h;%d\n", aSize.width, aSize.height);
+
+  const bool resized = aSize != mLastSizeRequest || mBounds.Size() != aSize;
+#if MOZ_LOGGING
+  LOG("  resized %d aSize [%d, %d] mLastSizeRequest [%d, %d] mBounds [%d, %d]",
+      resized, aSize.width, aSize.height, mLastSizeRequest.width,
+      mLastSizeRequest.height, mBounds.width, mBounds.height);
+#endif
+
+  // For top-level windows, aSize should possibly be
+  // interpreted as frame bounds, but NativeMoveResize treats these as window
+  // bounds (Bug 581866).
+  mLastSizeRequest = aSize;
+  // Check size
+  if (mCompositorSession &&
+      !wr::WindowSizeSanityCheck(aSize.width, aSize.height)) {
+    gfxCriticalNoteOnce << "Invalid aSize in ResizeInt " << aSize
+                        << " size state " << mSizeMode;
+  }
+
+  // Recalculate aspect ratio when resized from DOM
+  if (mAspectRatio != 0.0) {
+    LockAspectRatio(true);
+  }
+
+  if (!mCreated) {
+    return;
+  }
+
+  if (!moved && !resized) {
+    LOG("  not moved or resized, quit");
+    return;
+  }
+
+  NativeMoveResize(moved, resized);
+
+  // We optimistically assume size changes immediately in two cases:
+  // 1. Override-redirect window: Size is controlled by only us.
+  // 2. Managed window that has not not yet received a size-allocate event:
+  //    Resize() Callers expect initial sizes to be applied synchronously.
+  //    If the size request is not honored, then we'll correct in
+  //    OnSizeAllocate().
+  //
+  // When a managed window has already received a size-allocate, we cannot
+  // assume we'll always get a notification if our request does not get
+  // honored: "If the configure request has not changed, we don't ever resend
+  // it, because it could mean fighting the user or window manager."
+  // https://gitlab.gnome.org/GNOME/gtk/-/blob/3.24.31/gtk/gtkwindow.c#L9782
+  // So we don't update mBounds until OnSizeAllocate() when we know the
+  // request is granted.
+  bool isOrWillBeVisible = mHasReceivedSizeAllocate || mNeedsShow || mIsShown;
+  if (!isOrWillBeVisible ||
+      gtk_window_get_window_type(GTK_WINDOW(mShell)) == GTK_WINDOW_POPUP) {
+    mBounds.SizeTo(aSize);
+    if (mCompositorWidgetDelegate) {
+      mCompositorWidgetDelegate->NotifyClientSizeChanged(aSize);
+    }
+    DispatchResized();
+  }
+}
+
+void nsWindow::Resize(double aWidth, double aHeight, bool aRepaint) {
+  LOG("nsWindow::Resize %f %f\n", aWidth, aHeight);
+
+  double scale =
+      BoundsUseDesktopPixels() ? GetDesktopToDeviceScale().scale : 1.0;
+  auto size = LayoutDeviceIntSize::Round(scale * aWidth, scale * aHeight);
+
+  ResizeInt(Nothing(), size);
+}
+
+void nsWindow::Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) {
+  LOG("nsWindow::Resize [%f,%f] -> [%f x %f] repaint %d\n", aX, aY, aWidth,
+      aHeight, aRepaint);
+
+  double scale =
+      BoundsUseDesktopPixels() ? GetDesktopToDeviceScale().scale : 1.0;
+  auto size = LayoutDeviceIntSize::Round(scale * aWidth, scale * aHeight);
+  auto topLeft = LayoutDeviceIntPoint::Round(scale * aX, scale * aY);
+
+  ResizeInt(Some(topLeft), size);
+}
+
+void nsWindow::Enable(bool aState) { mEnabled = aState; }
+
+bool nsWindow::IsEnabled() const { return mEnabled; }
+
+void nsWindow::Move(double aX, double aY) {
+  double scale =
+      BoundsUseDesktopPixels() ? GetDesktopToDeviceScale().scale : 1.0;
+  int32_t x = NSToIntRound(aX * scale);
+  int32_t y = NSToIntRound(aY * scale);
+
+  LOG("nsWindow::Move to %d x %d\n", x, y);
+
+  if (mSizeMode != nsSizeMode_Normal && IsTopLevelWindowType()) {
+    LOG("  size state is not normal, bailing");
+    return;
+  }
+
+  // Since a popup window's x/y coordinates are in relation to to
+  // the parent, the parent might have moved so we always move a
+  // popup window.
+  LOG("  bounds %d x %d\n", mBounds.x, mBounds.y);
+  if (x == mBounds.x && y == mBounds.y && mWindowType != WindowType::Popup) {
+    LOG("  position is the same, return\n");
+    return;
+  }
+
+  // XXX Should we do some AreBoundsSane check here?
+
+  mBounds.x = x;
+  mBounds.y = y;
+
+  if (!mCreated) {
+    LOG("  is not created, return.\n");
+    return;
+  }
+
+  NativeMoveResize(/* move */ true, /* resize */ false);
+}
+
+bool nsWindow::IsPopup() const { return mWindowType == WindowType::Popup; }
+
+bool nsWindow::IsWaylandPopup() const {
+  return GdkIsWaylandDisplay() && IsPopup();
+}
+
+static nsMenuPopupFrame* GetMenuPopupFrame(nsIFrame* aFrame) {
+  return do_QueryFrame(aFrame);
+}
+
+void nsWindow::AppendPopupToHierarchyList(nsWindow* aToplevelWindow) {
+  mWaylandToplevel = aToplevelWindow;
+
+  nsWindow* popup = aToplevelWindow;
+  while (popup && popup->mWaylandPopupNext) {
+    popup = popup->mWaylandPopupNext;
+  }
+  popup->mWaylandPopupNext = this;
+
+  mWaylandPopupPrev = popup;
+  mWaylandPopupNext = nullptr;
+  mPopupChanged = true;
+  mPopupClosed = false;
+}
+
+void nsWindow::RemovePopupFromHierarchyList() {
+  // We're already removed from the popup hierarchy
+  if (!IsInPopupHierarchy()) {
+    return;
+  }
+  mWaylandPopupPrev->mWaylandPopupNext = mWaylandPopupNext;
+  if (mWaylandPopupNext) {
+    mWaylandPopupNext->mWaylandPopupPrev = mWaylandPopupPrev;
+    mWaylandPopupNext->mPopupChanged = true;
+  }
+  mWaylandPopupNext = mWaylandPopupPrev = nullptr;
+}
+
+// Gtk refuses to map popup window with x < 0 && y < 0 relative coordinates
+// see https://gitlab.gnome.org/GNOME/gtk/-/issues/4071
+// as a workaround just fool around and place the popup temporary to 0,0.
+bool nsWindow::WaylandPopupRemoveNegativePosition(int* aX, int* aY) {
+  // https://gitlab.gnome.org/GNOME/gtk/-/issues/4071 applies to temporary
+  // windows only
+  GdkWindow* window = GetToplevelGdkWindow();
+  if (!window || gdk_window_get_window_type(window) != GDK_WINDOW_TEMP) {
+    return false;
+  }
+
+  LOG("nsWindow::WaylandPopupRemoveNegativePosition()");
+
+  int x, y;
+  gtk_window_get_position(GTK_WINDOW(mShell), &x, &y);
+  bool moveBack = (x < 0 && y < 0);
+  if (moveBack) {
+    gtk_window_move(GTK_WINDOW(mShell), 0, 0);
+    if (aX) {
+      *aX = x;
+    }
+    if (aY) {
+      *aY = y;
+    }
+  }
+
+  gdk_window_get_geometry(window, &x, &y, nullptr, nullptr);
+  if (x < 0 && y < 0) {
+    gdk_window_move(window, 0, 0);
+  }
+
+  return moveBack;
+}
+
+void nsWindow::ShowWaylandPopupWindow() {
+  LOG("nsWindow::ShowWaylandPopupWindow. Expected to see visible.");
+  MOZ_ASSERT(IsWaylandPopup());
+
+  if (!mPopupTrackInHierarchy) {
+    LOG("  popup is not tracked in popup hierarchy, show it now");
+    gtk_widget_show(mShell);
+    return;
+  }
+
+  // Popup position was checked before gdk_window_move_to_rect() callback
+  // so just show it.
+  if (mPopupUseMoveToRect && mWaitingForMoveToRectCallback) {
+    LOG("  active move-to-rect callback, show it as is");
+    gtk_widget_show(mShell);
+    return;
+  }
+
+  if (gtk_widget_is_visible(mShell)) {
+    LOG("  is already visible, quit");
+    return;
+  }
+
+  int x, y;
+  bool moved = WaylandPopupRemoveNegativePosition(&x, &y);
+  gtk_widget_show(mShell);
+  if (moved) {
+    LOG("  move back to (%d, %d) and show", x, y);
+    gtk_window_move(GTK_WINDOW(mShell), x, y);
+  }
+}
+
+void nsWindow::WaylandPopupMarkAsClosed() {
+  LOG("nsWindow::WaylandPopupMarkAsClosed: [%p]\n", this);
+  mPopupClosed = true;
+  // If we have any child popup window notify it about
+  // parent switch.
+  if (mWaylandPopupNext) {
+    mWaylandPopupNext->mPopupChanged = true;
+  }
+}
+
+nsWindow* nsWindow::WaylandPopupFindLast(nsWindow* aPopup) {
+  while (aPopup && aPopup->mWaylandPopupNext) {
+    aPopup = aPopup->mWaylandPopupNext;
+  }
+  return aPopup;
+}
+
+// Hide and potentially removes popup from popup hierarchy.
+void nsWindow::HideWaylandPopupWindow(bool aTemporaryHide,
+                                      bool aRemoveFromPopupList) {
+  LOG("nsWindow::HideWaylandPopupWindow: remove from list %d\n",
+      aRemoveFromPopupList);
+  if (aRemoveFromPopupList) {
+    RemovePopupFromHierarchyList();
+  }
+
+  if (!mPopupClosed) {
+    mPopupClosed = !aTemporaryHide;
+  }
+
+  bool visible = gtk_widget_is_visible(mShell);
+  LOG("  gtk_widget_is_visible() = %d\n", visible);
+
+  // Restore only popups which are really visible
+  mPopupTemporaryHidden = aTemporaryHide && visible;
+
+  // Hide only visible popups or popups closed pernamently.
+  if (visible) {
+    gtk_widget_hide(mShell);
+
+    // If there's pending Move-To-Rect callback and we hide the popup
+    // the callback won't be called any more.
+    mWaitingForMoveToRectCallback = false;
+  }
+
+  if (mPopupClosed) {
+    LOG("  Clearing mMoveToRectPopupSize\n");
+    mMoveToRectPopupSize = {};
+#ifdef MOZ_WAYLAND
+    if (moz_container_wayland_is_waiting_to_show(mContainer)) {
+      // We need to clear rendering queue, see Bug 1782948.
+      LOG("  popup failed to show by Wayland compositor, clear rendering "
+          "queue.");
+      moz_container_wayland_clear_waiting_to_show_flag(mContainer);
+      ClearRenderingQueue();
+    }
+#endif
+  }
+}
+
+void nsWindow::HideWaylandToplevelWindow() {
+  LOG("nsWindow::HideWaylandToplevelWindow: [%p]\n", this);
+  if (mWaylandPopupNext) {
+    nsWindow* popup = WaylandPopupFindLast(mWaylandPopupNext);
+    while (popup->mWaylandToplevel != nullptr) {
+      nsWindow* prev = popup->mWaylandPopupPrev;
+      popup->HideWaylandPopupWindow(/* aTemporaryHide */ false,
+                                    /* aRemoveFromPopupList */ true);
+      popup = prev;
+    }
+  }
+  WaylandStopVsync();
+  gtk_widget_hide(mShell);
+}
+
+void nsWindow::ShowWaylandToplevelWindow() {
+  MOZ_ASSERT(!IsWaylandPopup());
+  LOG("nsWindow::ShowWaylandToplevelWindow");
+  gtk_widget_show(mShell);
+}
+
+void nsWindow::WaylandPopupRemoveClosedPopups() {
+  LOG("nsWindow::WaylandPopupRemoveClosedPopups()");
+  nsWindow* popup = this;
+  while (popup) {
+    nsWindow* next = popup->mWaylandPopupNext;
+    if (popup->mPopupClosed) {
+      popup->HideWaylandPopupWindow(/* aTemporaryHide */ false,
+                                    /* aRemoveFromPopupList */ true);
+    }
+    popup = next;
+  }
+}
+
+// Hide all tooltips except the latest one.
+void nsWindow::WaylandPopupHideTooltips() {
+  LOG("nsWindow::WaylandPopupHideTooltips");
+  MOZ_ASSERT(mWaylandToplevel == nullptr, "Should be called on toplevel only!");
+
+  nsWindow* popup = mWaylandPopupNext;
+  while (popup && popup->mWaylandPopupNext) {
+    if (popup->mPopupType == PopupType::Tooltip) {
+      LOG("  hidding tooltip [%p]", popup);
+      popup->WaylandPopupMarkAsClosed();
+    }
+    popup = popup->mWaylandPopupNext;
+  }
+}
+
+void nsWindow::WaylandPopupCloseOrphanedPopups() {
+#ifdef MOZ_WAYLAND
+  LOG("nsWindow::WaylandPopupCloseOrphanedPopups");
+  MOZ_ASSERT(mWaylandToplevel == nullptr, "Should be called on toplevel only!");
+
+  nsWindow* popup = mWaylandPopupNext;
+  bool dangling = false;
+  while (popup) {
+    if (!dangling &&
+        moz_container_wayland_is_waiting_to_show(popup->GetMozContainer())) {
+      LOG("  popup [%p] is waiting to show, close all child popups", popup);
+      dangling = true;
+    } else if (dangling) {
+      popup->WaylandPopupMarkAsClosed();
+    }
+    popup = popup->mWaylandPopupNext;
+  }
+#endif
+}
+
+// We can't show popups with remote content or overflow popups
+// on top of regular ones.
+// If there's any remote popup opened, close all parent popups of it.
+void nsWindow::CloseAllPopupsBeforeRemotePopup() {
+  LOG("nsWindow::CloseAllPopupsBeforeRemotePopup");
+  MOZ_ASSERT(mWaylandToplevel == nullptr, "Should be called on toplevel only!");
+
+  // Don't waste time when there's only one popup opened.
+  if (!mWaylandPopupNext || mWaylandPopupNext->mWaylandPopupNext == nullptr) {
+    return;
+  }
+
+  // Find the first opened remote content popup
+  nsWindow* remotePopup = mWaylandPopupNext;
+  while (remotePopup) {
+    if (remotePopup->HasRemoteContent() ||
+        remotePopup->IsWidgetOverflowWindow()) {
+      LOG("  remote popup [%p]", remotePopup);
+      break;
+    }
+    remotePopup = remotePopup->mWaylandPopupNext;
+  }
+
+  if (!remotePopup) {
+    return;
+  }
+
+  // ...hide opened popups before the remote one.
+  nsWindow* popup = mWaylandPopupNext;
+  while (popup && popup != remotePopup) {
+    LOG("  hidding popup [%p]", popup);
+    popup->WaylandPopupMarkAsClosed();
+    popup = popup->mWaylandPopupNext;
+  }
+}
+
+static void GetLayoutPopupWidgetChain(
+    nsTArray<nsIWidget*>* aLayoutWidgetHierarchy) {
+  nsXULPopupManager* pm = nsXULPopupManager::GetInstance();
+  pm->GetSubmenuWidgetChain(aLayoutWidgetHierarchy);
+  aLayoutWidgetHierarchy->Reverse();
+}
+
+// Compare 'this' popup position in Wayland widget hierarchy
+// (mWaylandPopupPrev/mWaylandPopupNext) with
+// 'this' popup position in layout hierarchy.
+//
+// When aMustMatchParent is true we also request
+// 'this' parents match, i.e. 'this' has the same parent in
+// both layout and widget hierarchy.
+bool nsWindow::IsPopupInLayoutPopupChain(
+    nsTArray<nsIWidget*>* aLayoutWidgetHierarchy, bool aMustMatchParent) {
+  int len = (int)aLayoutWidgetHierarchy->Length();
+  for (int i = 0; i < len; i++) {
+    if (this == (*aLayoutWidgetHierarchy)[i]) {
+      if (!aMustMatchParent) {
+        return true;
+      }
+
+      // Find correct parent popup for 'this' according to widget
+      // hierarchy. That means we need to skip closed popups.
+      nsWindow* parentPopup = nullptr;
+      if (mWaylandPopupPrev != mWaylandToplevel) {
+        parentPopup = mWaylandPopupPrev;
+        while (parentPopup != mWaylandToplevel && parentPopup->mPopupClosed) {
+          parentPopup = parentPopup->mWaylandPopupPrev;
+        }
+      }
+
+      if (i == 0) {
+        // We found 'this' popups as a first popup in layout hierarchy.
+        // It matches layout hierarchy if it's first widget also in
+        // wayland widget hierarchy (i.e. parent is null).
+        return parentPopup == nullptr;
+      }
+
+      return parentPopup == (*aLayoutWidgetHierarchy)[i - 1];
+    }
+  }
+  return false;
+}
+
+// Hide popups which are not in popup chain.
+void nsWindow::WaylandPopupHierarchyHideByLayout(
+    nsTArray<nsIWidget*>* aLayoutWidgetHierarchy) {
+  LOG("nsWindow::WaylandPopupHierarchyHideByLayout");
+  MOZ_ASSERT(mWaylandToplevel == nullptr, "Should be called on toplevel only!");
+
+  // Hide all popups which are not in layout popup chain
+  nsWindow* popup = mWaylandPopupNext;
+  while (popup) {
+    // Don't check closed popups and drag source popups and tooltips.
+    if (!popup->mPopupClosed && popup->mPopupType != PopupType::Tooltip &&
+        !popup->mSourceDragContext) {
+      if (!popup->IsPopupInLayoutPopupChain(aLayoutWidgetHierarchy,
+                                            /* aMustMatchParent */ false)) {
+        LOG("  hidding popup [%p]", popup);
+        popup->WaylandPopupMarkAsClosed();
+      }
+    }
+    popup = popup->mWaylandPopupNext;
+  }
+}
+
+// Mark popups outside of layout hierarchy
+void nsWindow::WaylandPopupHierarchyValidateByLayout(
+    nsTArray<nsIWidget*>* aLayoutWidgetHierarchy) {
+  LOG("nsWindow::WaylandPopupHierarchyValidateByLayout");
+  nsWindow* popup = mWaylandPopupNext;
+  while (popup) {
+    if (popup->mPopupType == PopupType::Tooltip) {
+      popup->mPopupMatchesLayout = true;
+    } else if (!popup->mPopupClosed) {
+      popup->mPopupMatchesLayout = popup->IsPopupInLayoutPopupChain(
+          aLayoutWidgetHierarchy, /* aMustMatchParent */ true);
+      LOG("  popup [%p] parent window [%p] matches layout %d\n", (void*)popup,
+          (void*)popup->mWaylandPopupPrev, popup->mPopupMatchesLayout);
+    }
+    popup = popup->mWaylandPopupNext;
+  }
+}
+
+void nsWindow::WaylandPopupHierarchyHideTemporary() {
+  LOG("nsWindow::WaylandPopupHierarchyHideTemporary()");
+  nsWindow* popup = WaylandPopupFindLast(this);
+  while (popup && popup != this) {
+    LOG("  temporary hidding popup [%p]", popup);
+    nsWindow* prev = popup->mWaylandPopupPrev;
+    popup->HideWaylandPopupWindow(/* aTemporaryHide */ true,
+                                  /* aRemoveFromPopupList */ false);
+    popup = prev;
+  }
+}
+
+void nsWindow::WaylandPopupHierarchyShowTemporaryHidden() {
+  LOG("nsWindow::WaylandPopupHierarchyShowTemporaryHidden()");
+  nsWindow* popup = this;
+  while (popup) {
+    if (popup->mPopupTemporaryHidden) {
+      popup->mPopupTemporaryHidden = false;
+      LOG("  showing temporary hidden popup [%p]", popup);
+      popup->ShowWaylandPopupWindow();
+    }
+    popup = popup->mWaylandPopupNext;
+  }
+}
+
+void nsWindow::WaylandPopupHierarchyCalculatePositions() {
+  LOG("nsWindow::WaylandPopupHierarchyCalculatePositions()");
+
+  // Set widget hierarchy in Gtk
+  nsWindow* popup = mWaylandToplevel->mWaylandPopupNext;
+  while (popup) {
+    LOG("  popup [%p] set parent window [%p]", (void*)popup,
+        (void*)popup->mWaylandPopupPrev);
+    GtkWindowSetTransientFor(GTK_WINDOW(popup->mShell),
+                             GTK_WINDOW(popup->mWaylandPopupPrev->mShell));
+    popup = popup->mWaylandPopupNext;
+  }
+
+  popup = this;
+  while (popup) {
+    // Anchored window has mPopupPosition already calculated against
+    // its parent, no need to recalculate.
+    LOG("  popup [%p] bounds [%d, %d] -> [%d x %d]", popup,
+        (int)(popup->mBounds.x / FractionalScaleFactor()),
+        (int)(popup->mBounds.y / FractionalScaleFactor()),
+        (int)(popup->mBounds.width / FractionalScaleFactor()),
+        (int)(popup->mBounds.height / FractionalScaleFactor()));
+#ifdef MOZ_LOGGING
+    if (LOG_ENABLED()) {
+      if (nsMenuPopupFrame* popupFrame = GetMenuPopupFrame(GetFrame())) {
+        auto r = LayoutDeviceRect::FromAppUnitsRounded(
+            popupFrame->GetRect(),
+            popupFrame->PresContext()->AppUnitsPerDevPixel());
+        LOG("  popup [%p] layout [%d, %d] -> [%d x %d]", popup, r.x, r.y,
+            r.width, r.height);
+      }
+    }
+#endif
+    if (popup->WaylandPopupIsFirst()) {
+      LOG("  popup [%p] has toplevel as parent", popup);
+      popup->mRelativePopupPosition = popup->mPopupPosition;
+    } else {
+      if (popup->mPopupAnchored) {
+        LOG("  popup [%p] is anchored", popup);
+        if (!popup->mPopupMatchesLayout) {
+          NS_WARNING("Anchored popup does not match layout!");
+        }
+      }
+      GdkPoint parent = popup->WaylandGetParentPosition();
+
+      LOG("  popup [%p] uses transformed coordinates\n", popup);
+      LOG("    parent position [%d, %d]\n", parent.x, parent.y);
+      LOG("    popup position [%d, %d]\n", popup->mPopupPosition.x,
+          popup->mPopupPosition.y);
+
+      popup->mRelativePopupPosition.x = popup->mPopupPosition.x - parent.x;
+      popup->mRelativePopupPosition.y = popup->mPopupPosition.y - parent.y;
+    }
+    LOG("  popup [%p] transformed popup coordinates from [%d, %d] to [%d, %d]",
+        popup, popup->mPopupPosition.x, popup->mPopupPosition.y,
+        popup->mRelativePopupPosition.x, popup->mRelativePopupPosition.y);
+    popup = popup->mWaylandPopupNext;
+  }
+}
+
+// The MenuList popups are used as dropdown menus for example in WebRTC
+// microphone/camera chooser or autocomplete widgets.
+bool nsWindow::WaylandPopupIsMenu() {
+  nsMenuPopupFrame* menuPopupFrame = GetMenuPopupFrame(GetFrame());
+  if (menuPopupFrame) {
+    return mPopupType == PopupType::Menu && !menuPopupFrame->IsMenuList();
+  }
+  return false;
+}
+
+bool nsWindow::WaylandPopupIsContextMenu() {
+  nsMenuPopupFrame* popupFrame = GetMenuPopupFrame(GetFrame());
+  if (!popupFrame) {
+    return false;
+  }
+  return popupFrame->IsContextMenu();
+}
+
+bool nsWindow::WaylandPopupIsPermanent() {
+  nsMenuPopupFrame* popupFrame = GetMenuPopupFrame(GetFrame());
+  if (!popupFrame) {
+    // We can always hide popups without frames.
+    return false;
+  }
+  return popupFrame->IsNoAutoHide();
+}
+
+bool nsWindow::WaylandPopupIsAnchored() {
+  nsMenuPopupFrame* popupFrame = GetMenuPopupFrame(GetFrame());
+  if (!popupFrame) {
+    // We can always hide popups without frames.
+    return false;
+  }
+  return !!popupFrame->GetAnchor();
+}
+
+bool nsWindow::IsWidgetOverflowWindow() {
+  if (this->GetFrame() && this->GetFrame()->GetContent()->GetID()) {
+    nsCString nodeId;
+    this->GetFrame()->GetContent()->GetID()->ToUTF8String(nodeId);
+    return nodeId.Equals("widget-overflow");
+  }
+  return false;
+}
+
+bool nsWindow::WaylandPopupIsFirst() {
+  return !mWaylandPopupPrev || !mWaylandPopupPrev->mWaylandToplevel;
+}
+
+nsWindow* nsWindow::GetEffectiveParent() {
+  GtkWindow* parentGtkWindow = gtk_window_get_transient_for(GTK_WINDOW(mShell));
+  if (!parentGtkWindow || !GTK_IS_WIDGET(parentGtkWindow)) {
+    return nullptr;
+  }
+  return get_window_for_gtk_widget(GTK_WIDGET(parentGtkWindow));
+}
+
+GdkPoint nsWindow::WaylandGetParentPosition() {
+  GdkPoint topLeft = {0, 0};
+  nsWindow* window = GetEffectiveParent();
+  if (window->IsPopup()) {
+    topLeft = DevicePixelsToGdkPointRoundDown(window->mBounds.TopLeft());
+  }
+  LOG("nsWindow::WaylandGetParentPosition() [%d, %d]\n", topLeft.x, topLeft.y);
+  return topLeft;
+}
+
+#ifdef MOZ_LOGGING
+void nsWindow::LogPopupHierarchy() {
+  if (!LOG_ENABLED()) {
+    return;
+  }
+
+  LOG("Widget Popup Hierarchy:\n");
+  if (!mWaylandToplevel->mWaylandPopupNext) {
+    LOG("    Empty\n");
+  } else {
+    int indent = 4;
+    nsWindow* popup = mWaylandToplevel->mWaylandPopupNext;
+    while (popup) {
+      nsPrintfCString indentString("%*s", indent, " ");
+      LOG("%s %s %s nsWindow [%p] Menu %d Permanent %d ContextMenu %d "
+          "Anchored %d Visible %d MovedByRect %d\n",
+          indentString.get(), popup->GetFrameTag().get(),
+          popup->GetPopupTypeName().get(), popup, popup->WaylandPopupIsMenu(),
+          popup->WaylandPopupIsPermanent(), popup->mPopupContextMenu,
+          popup->mPopupAnchored, gtk_widget_is_visible(popup->mShell),
+          popup->mPopupUseMoveToRect);
+      indent += 4;
+      popup = popup->mWaylandPopupNext;
+    }
+  }
+
+  LOG("Layout Popup Hierarchy:\n");
+  AutoTArray<nsIWidget*, 5> widgetChain;
+  GetLayoutPopupWidgetChain(&widgetChain);
+  if (widgetChain.Length() == 0) {
+    LOG("    Empty\n");
+  } else {
+    for (unsigned long i = 0; i < widgetChain.Length(); i++) {
+      nsWindow* window = static_cast<nsWindow*>(widgetChain[i]);
+      nsPrintfCString indentString("%*s", (int)(i + 1) * 4, " ");
+      if (window) {
+        LOG("%s %s %s nsWindow [%p] Menu %d Permanent %d ContextMenu %d "
+            "Anchored %d Visible %d MovedByRect %d\n",
+            indentString.get(), window->GetFrameTag().get(),
+            window->GetPopupTypeName().get(), window,
+            window->WaylandPopupIsMenu(), window->WaylandPopupIsPermanent(),
+            window->mPopupContextMenu, window->mPopupAnchored,
+            gtk_widget_is_visible(window->mShell), window->mPopupUseMoveToRect);
+      } else {
+        LOG("%s null window\n", indentString.get());
+      }
+    }
+  }
+}
+#endif
+
+nsWindow* nsWindow::GetTopmostWindow() {
+  if (nsView* view = nsView::GetViewFor(this)) {
+    if (nsView* parentView = view->GetParent()) {
+      if (nsIWidget* parentWidget = parentView->GetNearestWidget(nullptr)) {
+        return static_cast<nsWindow*>(parentWidget);
+      }
+    }
+  }
+  return nullptr;
+}
+
+// Configure Wayland popup. If true is returned we need to track popup
+// in popup hierarchy. Otherwise we just show it as is.
+bool nsWindow::WaylandPopupConfigure() {
+  if (mIsDragPopup) {
+    return false;
+  }
+
+  // Don't track popups without frame
+  nsMenuPopupFrame* popupFrame = GetMenuPopupFrame(GetFrame());
+  if (!popupFrame) {
+    return false;
+  }
+
+  // Popup state can be changed, see Bug 1728952.
+  bool permanentStateMatches =
+      mPopupTrackInHierarchy == !WaylandPopupIsPermanent();
+
+  // Popup permanent state (noautohide attribute) can change during popup life.
+  if (mPopupTrackInHierarchyConfigured && permanentStateMatches) {
+    return mPopupTrackInHierarchy;
+  }
+
+  // Configure persistent popup params only once.
+  // WaylandPopupIsAnchored() can give it wrong value after
+  // nsMenuPopupFrame::MoveTo() call which we use in move-to-rect callback
+  // to position popup after wayland position change.
+  if (!mPopupTrackInHierarchyConfigured) {
+    mPopupAnchored = WaylandPopupIsAnchored();
+    mPopupContextMenu = WaylandPopupIsContextMenu();
+  }
+
+  LOG("nsWindow::WaylandPopupConfigure tracked %d anchored %d hint %d\n",
+      mPopupTrackInHierarchy, mPopupAnchored, int(mPopupType));
+
+  // Permanent state changed and popup is mapped.
+  // We need to switch popup type but that's done when popup is mapped
+  // by Gtk so we need to unmap the popup here.
+  // It will be mapped again by gtk_widget_show().
+  if (!permanentStateMatches && mIsMapped) {
+    LOG("  permanent state change from %d to %d, unmapping",
+        mPopupTrackInHierarchy, !WaylandPopupIsPermanent());
+    gtk_widget_unmap(mShell);
+  }
+
+  mPopupTrackInHierarchy = !WaylandPopupIsPermanent();
+  LOG("  tracked in hierarchy %d\n", mPopupTrackInHierarchy);
+
+  // See gdkwindow-wayland.c and
+  // should_map_as_popup()/should_map_as_subsurface()
+  GdkWindowTypeHint gtkTypeHint;
+  switch (mPopupType) {
+    case PopupType::Menu:
+      // GDK_WINDOW_TYPE_HINT_POPUP_MENU is mapped as xdg_popup by default.
+      // We use this type for all menu popups.
+      gtkTypeHint = GDK_WINDOW_TYPE_HINT_POPUP_MENU;
+      LOG("  popup type Menu");
+      break;
+    case PopupType::Tooltip:
+      gtkTypeHint = GDK_WINDOW_TYPE_HINT_TOOLTIP;
+      LOG("  popup type Tooltip");
+      break;
+    default:
+      gtkTypeHint = GDK_WINDOW_TYPE_HINT_UTILITY;
+      LOG("  popup type Utility");
+      break;
+  }
+
+  if (!mPopupTrackInHierarchy) {
+    // GDK_WINDOW_TYPE_HINT_UTILITY is mapped as wl_subsurface
+    // by default.
+    LOG("  not tracked in popup hierarchy, switch to Utility");
+    gtkTypeHint = GDK_WINDOW_TYPE_HINT_UTILITY;
+  }
+  gtk_window_set_type_hint(GTK_WINDOW(mShell), gtkTypeHint);
+
+  mPopupTrackInHierarchyConfigured = true;
+  return mPopupTrackInHierarchy;
+}
+
+bool nsWindow::IsInPopupHierarchy() {
+  return mPopupTrackInHierarchy && mWaylandToplevel && mWaylandPopupPrev;
+}
+
+void nsWindow::AddWindowToPopupHierarchy() {
+  LOG("nsWindow::AddWindowToPopupHierarchy\n");
+  if (!GetFrame()) {
+    LOG("  Window without frame cannot be added as popup!\n");
+    return;
+  }
+
+  // Check if we're already in the hierarchy
+  if (!IsInPopupHierarchy()) {
+    mWaylandToplevel = GetTopmostWindow();
+    AppendPopupToHierarchyList(mWaylandToplevel);
+  }
+}
+
+// Wayland keeps strong popup window hierarchy. We need to track active
+// (visible) popup windows and make sure we hide popup on the same level
+// before we open another one on that level. It means that every open
+// popup needs to have an unique parent.
+void nsWindow::UpdateWaylandPopupHierarchy() {
+  LOG("nsWindow::UpdateWaylandPopupHierarchy\n");
+
+  // This popup hasn't been added to popup hierarchy yet so no need to
+  // do any configurations.
+  if (!IsInPopupHierarchy()) {
+    LOG("  popup isn't in hierarchy\n");
+    return;
+  }
+
+#ifdef MOZ_LOGGING
+  LogPopupHierarchy();
+  auto printPopupHierarchy = MakeScopeExit([&] { LogPopupHierarchy(); });
+#endif
+
+  // Hide all tooltips without the last one. Tooltip can't be popup parent.
+  mWaylandToplevel->WaylandPopupHideTooltips();
+
+  // See Bug 1709254 / https://gitlab.gnome.org/GNOME/gtk/-/issues/5092
+  // It's possible that Wayland compositor refuses to show
+  // a popup although Gtk claims it's visible.
+  // We don't know if the popup is shown or not.
+  // To avoid application crash refuse to create any child of such invisible
+  // popup and close any child of it now.
+  mWaylandToplevel->WaylandPopupCloseOrphanedPopups();
+
+  // Check if we have any remote content / overflow window in hierarchy.
+  // We can't attach such widget on top of other popup.
+  mWaylandToplevel->CloseAllPopupsBeforeRemotePopup();
+
+  // Check if your popup hierarchy matches layout hierarchy.
+  // For instance we should not connect hamburger menu on top
+  // of context menu.
+  // Close all popups from different layout chains if possible.
+  AutoTArray<nsIWidget*, 5> layoutPopupWidgetChain;
+  GetLayoutPopupWidgetChain(&layoutPopupWidgetChain);
+
+  mWaylandToplevel->WaylandPopupHierarchyHideByLayout(&layoutPopupWidgetChain);
+  mWaylandToplevel->WaylandPopupHierarchyValidateByLayout(
+      &layoutPopupWidgetChain);
+
+  // Now we have Popup hierarchy complete.
+  // Find first unchanged (and still open) popup to start with hierarchy
+  // changes.
+  nsWindow* changedPopup = mWaylandToplevel->mWaylandPopupNext;
+  while (changedPopup) {
+    // Stop when parent of this popup was changed and we need to recalc
+    // popup position.
+    if (changedPopup->mPopupChanged) {
+      break;
+    }
+    // Stop when this popup is closed.
+    if (changedPopup->mPopupClosed) {
+      break;
+    }
+    changedPopup = changedPopup->mWaylandPopupNext;
+  }
+
+  // We don't need to recompute popup positions, quit now.
+  if (!changedPopup) {
+    LOG("  changed Popup is null, quit.\n");
+    return;
+  }
+
+  LOG("  first changed popup [%p]\n", (void*)changedPopup);
+
+  // Hide parent popups if necessary (there are layout discontinuity)
+  // reposition the popup and show them again.
+  changedPopup->WaylandPopupHierarchyHideTemporary();
+
+  nsWindow* parentOfchangedPopup = nullptr;
+  if (changedPopup->mPopupClosed) {
+    parentOfchangedPopup = changedPopup->mWaylandPopupPrev;
+  }
+  changedPopup->WaylandPopupRemoveClosedPopups();
+
+  // It's possible that changedPopup was removed from widget hierarchy,
+  // in such case use child popup of the removed one if there's any.
+  if (!changedPopup->IsInPopupHierarchy()) {
+    if (!parentOfchangedPopup || !parentOfchangedPopup->mWaylandPopupNext) {
+      LOG("  last popup was removed, quit.\n");
+      return;
+    }
+    changedPopup = parentOfchangedPopup->mWaylandPopupNext;
+  }
+
+  GetLayoutPopupWidgetChain(&layoutPopupWidgetChain);
+  mWaylandToplevel->WaylandPopupHierarchyValidateByLayout(
+      &layoutPopupWidgetChain);
+
+  changedPopup->WaylandPopupHierarchyCalculatePositions();
+
+  nsWindow* popup = changedPopup;
+  while (popup) {
+    const bool useMoveToRect = [&] {
+      if (!StaticPrefs::widget_wayland_use_move_to_rect_AtStartup()) {
+        return false;  // Not available.
+      }
+      if (!popup->mPopupMatchesLayout) {
+        // We can use move_to_rect only when popups in popup hierarchy matches
+        // layout hierarchy as move_to_rect request that parent/child
+        // popups are adjacent.
+        return false;
+      }
+      if (popup->mPopupType == PopupType::Panel &&
+          popup->WaylandPopupIsFirst() &&
+          popup->WaylandPopupFitsToplevelWindow(/* aMove */ true)) {
+        // Workaround for https://gitlab.gnome.org/GNOME/gtk/-/issues/1986
+        //
+        // PopupType::Panel types are used for extension popups which may be
+        // resized. If such popup uses move-to-rect, we need to hide it before
+        // resize and show it again. That leads to massive flickering
+        // so use plain move if possible to avoid it.
+        //
+        // Bug 1760276 - don't use move-to-rect when popup is inside main
+        // Firefox window.
+        //
+        // Use it for first popups only due to another mutter bug
+        // https://gitlab.gnome.org/GNOME/gtk/-/issues/5089
+        // https://bugzilla.mozilla.org/show_bug.cgi?id=1784873
+        return false;
+      }
+      if (!popup->WaylandPopupIsFirst() &&
+          !popup->mWaylandPopupPrev->WaylandPopupIsFirst() &&
+          !popup->mWaylandPopupPrev->mPopupUseMoveToRect) {
+        // We can't use move-to-rect if there are more parents of
+        // wl_subsurface popups types.
+        //
+        // It's because wl_subsurface is ignored by xgd_popup
+        // (created by move-to-rect) so our popup scenario:
+        //
+        // toplevel -> xgd_popup(1) -> wl_subsurface(2) -> xgd_popup(3)
+        //
+        // looks for Wayland compositor as:
+        //
+        // toplevel -> xgd_popup(1) -> xgd_popup(3)
+        //
+        // If xgd_popup(1) and xgd_popup(3) are not connected
+        // move-to-rect applied to xgd_popup(3) fails and we get missing popup.
+        return false;
+      }
+      return true;
+    }();
+
+    LOG("  popup [%p] matches layout [%d] anchored [%d] first popup [%d] use "
+        "move-to-rect %d\n",
+        popup, popup->mPopupMatchesLayout, popup->mPopupAnchored,
+        popup->WaylandPopupIsFirst(), useMoveToRect);
+
+    popup->mPopupUseMoveToRect = useMoveToRect;
+    popup->WaylandPopupMoveImpl();
+    popup->mPopupChanged = false;
+    popup = popup->mWaylandPopupNext;
+  }
+
+  changedPopup->WaylandPopupHierarchyShowTemporaryHidden();
+}
+
+static void NativeMoveResizeCallback(GdkWindow* window,
+                                     const GdkRectangle* flipped_rect,
+                                     const GdkRectangle* final_rect,
+                                     gboolean flipped_x, gboolean flipped_y,
+                                     void* aWindow) {
+  LOG_POPUP("[%p] NativeMoveResizeCallback flipped_x %d flipped_y %d\n",
+            aWindow, flipped_x, flipped_y);
+  LOG_POPUP("[%p]    new position [%d, %d] -> [%d x %d]", aWindow,
+            final_rect->x, final_rect->y, final_rect->width,
+            final_rect->height);
+  nsWindow* wnd = get_window_for_gdk_window(window);
+
+  wnd->NativeMoveResizeWaylandPopupCallback(final_rect, flipped_x, flipped_y);
+}
+
+// When popup is repositioned by widget code, we need to notify
+// layout about it. It's because we control popup placement
+// on widget on Wayland so layout may have old popup size/coordinates.
+void nsWindow::WaylandPopupPropagateChangesToLayout(bool aMove, bool aResize) {
+  LOG("nsWindow::WaylandPopupPropagateChangesToLayout()");
+
+  if (aResize) {
+    LOG("  needSizeUpdate\n");
+    if (nsMenuPopupFrame* popupFrame = GetMenuPopupFrame(GetFrame())) {
+      RefPtr<PresShell> presShell = popupFrame->PresShell();
+      presShell->FrameNeedsReflow(popupFrame, IntrinsicDirty::None,
+                                  NS_FRAME_IS_DIRTY);
+    }
+  }
+  if (aMove) {
+    LOG("  needPositionUpdate, bounds [%d, %d]", mBounds.x, mBounds.y);
+    NotifyWindowMoved(mBounds.x, mBounds.y, ByMoveToRect::Yes);
+  }
+}
+
+void nsWindow::NativeMoveResizeWaylandPopupCallback(
+    const GdkRectangle* aFinalSize, bool aFlippedX, bool aFlippedY) {
+  // We're getting move-to-rect callback without move-to-rect call.
+  // That indicates a compositor bug. It happens when a window is hidden and
+  // shown again before move-to-rect callback is fired.
+  // It may lead to incorrect popup placement as we may call
+  // gtk_window_move() between hide & show.
+  // See Bug 1777919, 1789581.
+#if MOZ_LOGGING
+  if (!mWaitingForMoveToRectCallback) {
+    LOG("  Bogus move-to-rect callback! Expect wrong popup coordinates.");
+  }
+#endif
+
+  mWaitingForMoveToRectCallback = false;
+
+  bool movedByLayout = mMovedAfterMoveToRect;
+  bool resizedByLayout = mResizedAfterMoveToRect;
+
+  // Popup was moved between move-to-rect call and move-to-rect callback
+  // and the coordinates from move-to-rect callback are outdated.
+  if (movedByLayout || resizedByLayout) {
+    LOG("  Another move/resize called during waiting for callback\n");
+    mMovedAfterMoveToRect = false;
+    mResizedAfterMoveToRect = false;
+    // Fire another round of move/resize to reflect latest request
+    // from layout.
+    NativeMoveResize(movedByLayout, resizedByLayout);
+    return;
+  }
+
+  LOG("  orig mBounds [%d, %d] -> [%d x %d]\n", mBounds.x, mBounds.y,
+      mBounds.width, mBounds.height);
+
+  LayoutDeviceIntRect newBounds = [&] {
+    GdkRectangle finalRect = *aFinalSize;
+    GdkPoint parent = WaylandGetParentPosition();
+    finalRect.x += parent.x;
+    finalRect.y += parent.y;
+    return GdkRectToDevicePixels(finalRect);
+  }();
+
+  LOG("  new mBounds [%d, %d] -> [%d x %d]", newBounds.x, newBounds.y,
+      newBounds.width, newBounds.height);
+
+  bool needsPositionUpdate = newBounds.TopLeft() != mBounds.TopLeft();
+  bool needsSizeUpdate = newBounds.Size() != mLastSizeRequest;
+
+  if (needsSizeUpdate) {
+    // Wayland compositor changed popup size request from layout.
+    // Set the constraints to use them in nsMenuPopupFrame::SetPopupPosition().
+    // Beware that gtk_window_resize() requests sizes asynchronously and so
+    // newBounds might not have the size from the most recent
+    // gtk_window_resize().
+    if (newBounds.width < mLastSizeRequest.width) {
+      mMoveToRectPopupSize.width = newBounds.width;
+    }
+    if (newBounds.height < mLastSizeRequest.height) {
+      mMoveToRectPopupSize.height = newBounds.height;
+    }
+    LOG("  mMoveToRectPopupSize set to [%d, %d]", mMoveToRectPopupSize.width,
+        mMoveToRectPopupSize.height);
+  }
+  mBounds = newBounds;
+  // Check mBounds size
+  if (mCompositorSession &&
+      !wr::WindowSizeSanityCheck(mBounds.width, mBounds.height)) {
+    gfxCriticalNoteOnce << "Invalid mBounds in PopupCallback " << mBounds
+                        << " size state " << mSizeMode;
+  }
+  WaylandPopupPropagateChangesToLayout(needsPositionUpdate, needsSizeUpdate);
+}
+
+static GdkGravity PopupAlignmentToGdkGravity(int8_t aAlignment) {
+  switch (aAlignment) {
+    case POPUPALIGNMENT_NONE:
+      return GDK_GRAVITY_NORTH_WEST;
+    case POPUPALIGNMENT_TOPLEFT:
+      return GDK_GRAVITY_NORTH_WEST;
+    case POPUPALIGNMENT_TOPRIGHT:
+      return GDK_GRAVITY_NORTH_EAST;
+    case POPUPALIGNMENT_BOTTOMLEFT:
+      return GDK_GRAVITY_SOUTH_WEST;
+    case POPUPALIGNMENT_BOTTOMRIGHT:
+      return GDK_GRAVITY_SOUTH_EAST;
+    case POPUPALIGNMENT_LEFTCENTER:
+      return GDK_GRAVITY_WEST;
+    case POPUPALIGNMENT_RIGHTCENTER:
+      return GDK_GRAVITY_EAST;
+    case POPUPALIGNMENT_TOPCENTER:
+      return GDK_GRAVITY_NORTH;
+    case POPUPALIGNMENT_BOTTOMCENTER:
+      return GDK_GRAVITY_SOUTH;
+  }
+  return GDK_GRAVITY_STATIC;
+}
+
+bool nsWindow::IsPopupDirectionRTL() {
+  nsMenuPopupFrame* popupFrame = GetMenuPopupFrame(GetFrame());
+  return popupFrame && popupFrame->IsDirectionRTL();
+}
+
+// Position the popup directly by gtk_window_move() and try to keep it
+// on screen by just moving it in scope of it's parent window.
+//
+// It's used when we position noautihode popup and we don't use xdg_positioner.
+// See Bug 1718867
+void nsWindow::WaylandPopupSetDirectPosition() {
+  GdkPoint topLeft = DevicePixelsToGdkPointRoundDown(mBounds.TopLeft());
+  GdkRectangle size = DevicePixelsToGdkSizeRoundUp(mLastSizeRequest);
+
+  LOG("nsWindow::WaylandPopupSetDirectPosition %d,%d -> %d x %d\n", topLeft.x,
+      topLeft.y, size.width, size.height);
+
+  mPopupPosition = {topLeft.x, topLeft.y};
+
+  if (mIsDragPopup) {
+    gtk_window_move(GTK_WINDOW(mShell), topLeft.x, topLeft.y);
+    gtk_window_resize(GTK_WINDOW(mShell), size.width, size.height);
+    // DND window is placed inside container so we need to make hard size
+    // request to ensure parent container is resized too.
+    gtk_widget_set_size_request(GTK_WIDGET(mShell), size.width, size.height);
+    return;
+  }
+
+  GtkWindow* parentGtkWindow = gtk_window_get_transient_for(GTK_WINDOW(mShell));
+  nsWindow* window = get_window_for_gtk_widget(GTK_WIDGET(parentGtkWindow));
+  if (!window) {
+    return;
+  }
+  GdkWindow* gdkWindow = window->GetGdkWindow();
+  if (!gdkWindow) {
+    return;
+  }
+
+  int parentWidth = gdk_window_get_width(gdkWindow);
+  int popupWidth = size.width;
+
+  int x;
+  gdk_window_get_position(gdkWindow, &x, nullptr);
+
+  // If popup is bigger than main window just center it.
+  if (popupWidth > parentWidth) {
+    mPopupPosition.x = -(parentWidth - popupWidth) / 2 + x;
+  } else {
+    if (IsPopupDirectionRTL()) {
+      // Stick with right window edge
+      if (mPopupPosition.x < x) {
+        mPopupPosition.x = x;
+      }
+    } else {
+      // Stick with left window edge
+      if (mPopupPosition.x + popupWidth > parentWidth + x) {
+        mPopupPosition.x = parentWidth + x - popupWidth;
+      }
+    }
+  }
+
+  LOG("  set position [%d, %d]\n", mPopupPosition.x, mPopupPosition.y);
+  gtk_window_move(GTK_WINDOW(mShell), mPopupPosition.x, mPopupPosition.y);
+
+  LOG("  set size [%d, %d]\n", size.width, size.height);
+  gtk_window_resize(GTK_WINDOW(mShell), size.width, size.height);
+
+  if (mPopupPosition.x != topLeft.x) {
+    mBounds.MoveTo(GdkPointToDevicePixels(mPopupPosition));
+    LOG("  setting new bounds [%d, %d]\n", mBounds.x, mBounds.y);
+    WaylandPopupPropagateChangesToLayout(/* move */ true, /* resize */ false);
+  }
+}
+
+bool nsWindow::WaylandPopupFitsToplevelWindow(bool aMove) {
+  LOG("nsWindow::WaylandPopupFitsToplevelWindow() move %d", aMove);
+
+  GtkWindow* parent = gtk_window_get_transient_for(GTK_WINDOW(mShell));
+  GtkWindow* tmp = parent;
+  while ((tmp = gtk_window_get_transient_for(GTK_WINDOW(parent)))) {
+    parent = tmp;
+  }
+  GdkWindow* toplevelGdkWindow = gtk_widget_get_window(GTK_WIDGET(parent));
+  if (!toplevelGdkWindow) {
+    NS_WARNING("Toplevel widget without GdkWindow?");
+    return false;
+  }
+
+  int parentWidth = gdk_window_get_width(toplevelGdkWindow);
+  int parentHeight = gdk_window_get_height(toplevelGdkWindow);
+  LOG("  parent size %d x %d", parentWidth, parentHeight);
+
+  GdkPoint topLeft = aMove ? mPopupPosition
+                           : DevicePixelsToGdkPointRoundDown(mBounds.TopLeft());
+  GdkRectangle size = DevicePixelsToGdkSizeRoundUp(mLastSizeRequest);
+  LOG("  popup topleft %d, %d size %d x %d", topLeft.x, topLeft.y, size.width,
+      size.height);
+  int fits = topLeft.x >= 0 && topLeft.y >= 0 &&
+             topLeft.x + size.width <= parentWidth &&
+             topLeft.y + size.height <= parentHeight;
+
+  LOG("  fits %d", fits);
+  return fits;
+}
+
+void nsWindow::NativeMoveResizeWaylandPopup(bool aMove, bool aResize) {
+  GdkPoint topLeft = DevicePixelsToGdkPointRoundDown(mBounds.TopLeft());
+  GdkRectangle size = DevicePixelsToGdkSizeRoundUp(mLastSizeRequest);
+
+  LOG("nsWindow::NativeMoveResizeWaylandPopup Bounds %d,%d -> %d x %d move %d "
+      "resize %d\n",
+      topLeft.x, topLeft.y, size.width, size.height, aMove, aResize);
+
+  // Compositor may be confused by windows with width/height = 0
+  // and positioning such windows leads to Bug 1555866.
+  if (!AreBoundsSane()) {
+    LOG("  Bounds are not sane (width: %d height: %d)\n",
+        mLastSizeRequest.width, mLastSizeRequest.height);
+    return;
+  }
+
+  if (mWaitingForMoveToRectCallback) {
+    LOG("  waiting for move to rect, scheduling");
+    // mBounds position must not be overwritten before it is applied.
+    // OnConfigureEvent() will not set mBounds to an old position for
+    // GTK_WINDOW_POPUP.
+    MOZ_ASSERT(gtk_window_get_window_type(GTK_WINDOW(mShell)) ==
+               GTK_WINDOW_POPUP);
+    mMovedAfterMoveToRect = aMove;
+    mResizedAfterMoveToRect = aResize;
+    return;
+  }
+
+  mMovedAfterMoveToRect = false;
+  mResizedAfterMoveToRect = false;
+
+  bool trackedInHierarchy = WaylandPopupConfigure();
+
+  // Read popup position from layout if it was moved or newly created.
+  // This position is used by move-to-rect method as we need anchor and other
+  // info to place popup correctly.
+  // We need WaylandPopupConfigure() to be called before to have all needed
+  // popup info in place (mainly the anchored flag).
+  if (aMove) {
+    mPopupMoveToRectParams = WaylandPopupGetPositionFromLayout();
+  }
+
+  if (!trackedInHierarchy) {
+    WaylandPopupSetDirectPosition();
+    return;
+  }
+
+  if (aResize) {
+    LOG("  set size [%d, %d]\n", size.width, size.height);
+    gtk_window_resize(GTK_WINDOW(mShell), size.width, size.height);
+  }
+
+  if (!aMove && WaylandPopupFitsToplevelWindow(aMove)) {
+    // Popup position has not been changed and its position/size fits
+    // parent window so no need to reposition the window.
+    LOG("  fits parent window size, just resize\n");
+    return;
+  }
+
+  // Mark popup as changed as we're updating position/size.
+  mPopupChanged = true;
+
+  // Save popup position for former re-calculations when popup hierarchy
+  // is changed.
+  LOG("  popup position changed from [%d, %d] to [%d, %d]\n", mPopupPosition.x,
+      mPopupPosition.y, topLeft.x, topLeft.y);
+  mPopupPosition = {topLeft.x, topLeft.y};
+
+  UpdateWaylandPopupHierarchy();
+}
+
+struct PopupSides {
+  Maybe<Side> mVertical;
+  Maybe<Side> mHorizontal;
+};
+
+static PopupSides SidesForPopupAlignment(int8_t aAlignment) {
+  switch (aAlignment) {
+    case POPUPALIGNMENT_NONE:
+      break;
+    case POPUPALIGNMENT_TOPLEFT:
+      return {Some(eSideTop), Some(eSideLeft)};
+    case POPUPALIGNMENT_TOPRIGHT:
+      return {Some(eSideTop), Some(eSideRight)};
+    case POPUPALIGNMENT_BOTTOMLEFT:
+      return {Some(eSideBottom), Some(eSideLeft)};
+    case POPUPALIGNMENT_BOTTOMRIGHT:
+      return {Some(eSideBottom), Some(eSideRight)};
+    case POPUPALIGNMENT_LEFTCENTER:
+      return {Nothing(), Some(eSideLeft)};
+    case POPUPALIGNMENT_RIGHTCENTER:
+      return {Nothing(), Some(eSideRight)};
+    case POPUPALIGNMENT_TOPCENTER:
+      return {Some(eSideTop), Nothing()};
+    case POPUPALIGNMENT_BOTTOMCENTER:
+      return {Some(eSideBottom), Nothing()};
+  }
+  return {};
+}
+
+// We want to apply margins based on popup alignment (which would generally be
+// just an offset to apply to the popup). However, to deal with flipping
+// correctly, we apply the margin to the anchor when possible.
+struct ResolvedPopupMargin {
+  // A margin to be applied to the anchor.
+  nsMargin mAnchorMargin;
+  // An offset in app units to be applied to the popup for when we need to tell
+  // GTK to center inside the anchor precisely (so we can't really do better in
+  // presence of flips).
+  nsPoint mPopupOffset;
+};
+
+static ResolvedPopupMargin ResolveMargin(nsMenuPopupFrame* aFrame,
+                                         int8_t aPopupAlign,
+                                         int8_t aAnchorAlign,
+                                         bool aAnchoredToPoint,
+                                         bool aIsContextMenu) {
+  nsMargin margin = aFrame->GetMargin();
+  nsPoint offset;
+
+  if (aAnchoredToPoint) {
+    // Since GTK doesn't allow us to specify margins itself, when anchored to a
+    // point we can just assume we'll be aligned correctly... This is kind of
+    // annoying but alas.
+    //
+    // This calculation must match the relevant unanchored popup calculation in
+    // nsMenuPopupFrame::SetPopupPosition(), which should itself be the inverse
+    // inverse of nsMenuPopupFrame::MoveTo().
+    if (aIsContextMenu && aFrame->IsDirectionRTL()) {
+      offset.x = -margin.right;
+    } else {
+      offset.x = margin.left;
+    }
+    offset.y = margin.top;
+    return {nsMargin(), offset};
+  }
+
+  auto popupSides = SidesForPopupAlignment(aPopupAlign);
+  auto anchorSides = SidesForPopupAlignment(aAnchorAlign);
+  // Matched sides: Invert the margin, so that we pull in the right direction.
+  // Popup not aligned to any anchor side: We give up and use the offset,
+  // applying the margin from the popup side.
+  // Mismatched sides: We swap the margins so that we pull in the right
+  // direction, e.g. margin-left: -10px should shrink 10px the _right_ of the
+  // box, not the left of the box.
+  if (popupSides.mHorizontal == anchorSides.mHorizontal) {
+    margin.left = -margin.left;
+    margin.right = -margin.right;
+  } else if (!anchorSides.mHorizontal) {
+    auto popupSide = *popupSides.mHorizontal;
+    offset.x += popupSide == eSideRight ? -margin.Side(popupSide)
+                                        : margin.Side(popupSide);
+    margin.left = margin.right = 0;
+  } else {
+    std::swap(margin.left, margin.right);
+  }
+
+  // Same logic as above, but in the vertical direction.
+  if (popupSides.mVertical == anchorSides.mVertical) {
+    margin.top = -margin.top;
+    margin.bottom = -margin.bottom;
+  } else if (!anchorSides.mVertical) {
+    auto popupSide = *popupSides.mVertical;
+    offset.y += popupSide == eSideBottom ? -margin.Side(popupSide)
+                                         : margin.Side(popupSide);
+    margin.top = margin.bottom = 0;
+  } else {
+    std::swap(margin.top, margin.bottom);
+  }
+
+  return {margin, offset};
+}
+
+#ifdef MOZ_LOGGING
+void nsWindow::LogPopupAnchorHints(int aHints) {
+  static struct hints_ {
+    int hint;
+    char name[100];
+  } hints[] = {
+      {GDK_ANCHOR_FLIP_X, "GDK_ANCHOR_FLIP_X"},
+      {GDK_ANCHOR_FLIP_Y, "GDK_ANCHOR_FLIP_Y"},
+      {GDK_ANCHOR_SLIDE_X, "GDK_ANCHOR_SLIDE_X"},
+      {GDK_ANCHOR_SLIDE_Y, "GDK_ANCHOR_SLIDE_Y"},
+      {GDK_ANCHOR_RESIZE_X, "GDK_ANCHOR_RESIZE_X"},
+      {GDK_ANCHOR_RESIZE_Y, "GDK_ANCHOR_RESIZE_X"},
+  };
+
+  LOG("  PopupAnchorHints");
+  for (const auto& hint : hints) {
+    if (hint.hint & aHints) {
+      LOG("    %s", hint.name);
+    }
+  }
+}
+
+void nsWindow::LogPopupGravity(GdkGravity aGravity) {
+  static char gravity[][100]{"NONE",
+                             "GDK_GRAVITY_NORTH_WEST",
+                             "GDK_GRAVITY_NORTH",
+                             "GDK_GRAVITY_NORTH_EAST",
+                             "GDK_GRAVITY_WEST",
+                             "GDK_GRAVITY_CENTER",
+                             "GDK_GRAVITY_EAST",
+                             "GDK_GRAVITY_SOUTH_WEST",
+                             "GDK_GRAVITY_SOUTH",
+                             "GDK_GRAVITY_SOUTH_EAST",
+                             "GDK_GRAVITY_STATIC"};
+  LOG("    %s", gravity[aGravity]);
+}
+#endif
+
+const nsWindow::WaylandPopupMoveToRectParams
+nsWindow::WaylandPopupGetPositionFromLayout() {
+  LOG("nsWindow::WaylandPopupGetPositionFromLayout\n");
+
+  nsMenuPopupFrame* popupFrame = GetMenuPopupFrame(GetFrame());
+
+  const bool isTopContextMenu = mPopupContextMenu && !mPopupAnchored;
+  const bool isRTL = IsPopupDirectionRTL();
+  const bool anchored = popupFrame->IsAnchored();
+  int8_t popupAlign = POPUPALIGNMENT_TOPLEFT;
+  int8_t anchorAlign = POPUPALIGNMENT_BOTTOMRIGHT;
+  if (anchored) {
+    // See nsMenuPopupFrame::AdjustPositionForAnchorAlign.
+    popupAlign = popupFrame->GetPopupAlignment();
+    anchorAlign = popupFrame->GetPopupAnchor();
+  }
+  if (isRTL && (anchored || isTopContextMenu)) {
+    popupAlign = -popupAlign;
+    anchorAlign = -anchorAlign;
+  }
+
+  // Although we have mPopupPosition / mRelativePopupPosition here
+  // we can't use it. move-to-rect needs anchor rectangle to position a popup
+  // but we have only a point from Resize().
+  //
+  // So we need to extract popup position from nsMenuPopupFrame() and duplicate
+  // the layout work here.
+  LayoutDeviceIntRect anchorRect;
+  ResolvedPopupMargin popupMargin;
+  {
+    nsRect anchorRectAppUnits = popupFrame->GetUntransformedAnchorRect();
+    // This is a somewhat hacky way of applying the popup margin. We don't know
+    // if GTK will end up flipping the popup, in which case the offset we
+    // compute is just wrong / applied to the wrong side.
+    //
+    // Instead, we tell it to anchor us at a smaller or bigger rect depending on
+    // the margin, which achieves the same result if the popup is positioned
+    // correctly, but doesn't misposition the popup when flipped across the
+    // anchor.
+    popupMargin = ResolveMargin(popupFrame, popupAlign, anchorAlign,
+                                anchorRectAppUnits.IsEmpty(), isTopContextMenu);
+    LOG("  layout popup CSS anchor (%d, %d) %s, margin %s offset %s\n",
+        popupAlign, anchorAlign, ToString(anchorRectAppUnits).c_str(),
+        ToString(popupMargin.mAnchorMargin).c_str(),
+        ToString(popupMargin.mPopupOffset).c_str());
+    anchorRectAppUnits.Inflate(popupMargin.mAnchorMargin);
+    LOG("    after margins %s\n", ToString(anchorRectAppUnits).c_str());
+    nscoord auPerDev = popupFrame->PresContext()->AppUnitsPerDevPixel();
+    anchorRect = LayoutDeviceIntRect::FromAppUnitsToNearest(anchorRectAppUnits,
+                                                            auPerDev);
+    if (anchorRect.width < 0) {
+      auto w = -anchorRect.width;
+      anchorRect.width += w + 1;
+      anchorRect.x += w;
+    }
+    LOG("    final %s\n", ToString(anchorRect).c_str());
+  }
+
+  LOG("  relative popup rect position [%d, %d] -> [%d x %d]\n", anchorRect.x,
+      anchorRect.y, anchorRect.width, anchorRect.height);
+
+  // Get gravity and flip type
+  GdkGravity rectAnchor = PopupAlignmentToGdkGravity(anchorAlign);
+  GdkGravity menuAnchor = PopupAlignmentToGdkGravity(popupAlign);
+
+  LOG("  parentRect gravity: %d anchor gravity: %d\n", rectAnchor, menuAnchor);
+
+  // Gtk default is: GDK_ANCHOR_FLIP | GDK_ANCHOR_SLIDE | GDK_ANCHOR_RESIZE.
+  // We want to SLIDE_X menu on the dual monitor setup rather than resize it
+  // on the other monitor.
+  GdkAnchorHints hints =
+      GdkAnchorHints(GDK_ANCHOR_FLIP | GDK_ANCHOR_SLIDE_X | GDK_ANCHOR_RESIZE);
+
+  // slideHorizontal from nsMenuPopupFrame::SetPopupPosition
+  int8_t position = popupFrame->GetAlignmentPosition();
+  if (position >= POPUPPOSITION_BEFORESTART &&
+      position <= POPUPPOSITION_AFTEREND) {
+    hints = GdkAnchorHints(hints | GDK_ANCHOR_SLIDE_X);
+  }
+  // slideVertical from nsMenuPopupFrame::SetPopupPosition
+  if (position >= POPUPPOSITION_STARTBEFORE &&
+      position <= POPUPPOSITION_ENDAFTER) {
+    hints = GdkAnchorHints(hints | GDK_ANCHOR_SLIDE_Y);
+  }
+
+  FlipType flipType = popupFrame->GetFlipType();
+  if (rectAnchor == GDK_GRAVITY_CENTER && menuAnchor == GDK_GRAVITY_CENTER) {
+    // only slide
+    hints = GdkAnchorHints(hints | GDK_ANCHOR_SLIDE);
+  } else {
+    switch (flipType) {
+      case FlipType_Both:
+        hints = GdkAnchorHints(hints | GDK_ANCHOR_FLIP);
+        break;
+      case FlipType_Slide:
+        hints = GdkAnchorHints(hints | GDK_ANCHOR_SLIDE);
+        break;
+      case FlipType_Default:
+        hints = GdkAnchorHints(hints | GDK_ANCHOR_FLIP);
+        break;
+      default:
+        break;
+    }
+  }
+  if (!WaylandPopupIsMenu()) {
+    // we don't want to slide menus to fit the screen rather resize them
+    hints = GdkAnchorHints(hints | GDK_ANCHOR_SLIDE);
+  }
+
+  // We want tooltips to flip verticaly or slide only.
+  // See nsMenuPopupFrame::SetPopupPosition().
+  // https://searchfox.org/mozilla-central/rev/d0f5bc50aff3462c9d1546b88d60c5cb020eb15c/layout/xul/nsMenuPopupFrame.cpp#1603
+  if (mPopupType == PopupType::Tooltip) {
+    hints = GdkAnchorHints(GDK_ANCHOR_FLIP_Y | GDK_ANCHOR_SLIDE);
+  }
+
+  return {
+      anchorRect,
+      rectAnchor,
+      menuAnchor,
+      hints,
+      DevicePixelsToGdkPointRoundDown(LayoutDevicePoint::FromAppUnitsToNearest(
+          popupMargin.mPopupOffset,
+          popupFrame->PresContext()->AppUnitsPerDevPixel())),
+      true};
+}
+
+bool nsWindow::WaylandPopupAnchorAdjustForParentPopup(
+    GdkRectangle* aPopupAnchor, GdkPoint* aOffset) {
+  LOG("nsWindow::WaylandPopupAnchorAdjustForParentPopup");
+
+  GtkWindow* parentGtkWindow = gtk_window_get_transient_for(GTK_WINDOW(mShell));
+  if (!parentGtkWindow || !GTK_IS_WIDGET(parentGtkWindow)) {
+    NS_WARNING("Popup has no parent!");
+    return false;
+  }
+  GdkWindow* window = gtk_widget_get_window(GTK_WIDGET(parentGtkWindow));
+  if (!window) {
+    NS_WARNING("Popup parrent is not mapped!");
+    return false;
+  }
+
+  GdkRectangle parentWindowRect = {0, 0, gdk_window_get_width(window),
+                                   gdk_window_get_height(window)};
+  LOG("  parent window size %d x %d", parentWindowRect.width,
+      parentWindowRect.height);
+
+  // We can't have rectangle anchor with zero width/height.
+  if (!aPopupAnchor->width) {
+    aPopupAnchor->width = 1;
+  }
+  if (!aPopupAnchor->height) {
+    aPopupAnchor->height = 1;
+  }
+
+  GdkRectangle finalRect;
+  if (!gdk_rectangle_intersect(aPopupAnchor, &parentWindowRect, &finalRect)) {
+    return false;
+  }
+  *aPopupAnchor = finalRect;
+  LOG("  anchor is correct %d,%d -> %d x %d", finalRect.x, finalRect.y,
+      finalRect.width, finalRect.height);
+
+  *aOffset = mPopupMoveToRectParams.mOffset;
+  LOG("  anchor offset %d, %d", aOffset->x, aOffset->y);
+  return true;
+}
+
+bool nsWindow::WaylandPopupCheckAndGetAnchor(GdkRectangle* aPopupAnchor,
+                                             GdkPoint* aOffset) {
+  LOG("nsWindow::WaylandPopupCheckAndGetAnchor");
+
+  GdkWindow* gdkWindow = GetToplevelGdkWindow();
+  nsMenuPopupFrame* popupFrame = GetMenuPopupFrame(GetFrame());
+  if (!gdkWindow || !popupFrame) {
+    LOG("  can't use move-to-rect due missing gdkWindow or popupFrame");
+    return false;
+  }
+
+  if (popupFrame->IsConstrainedByLayout()) {
+    LOG("  can't use move-to-rect, flipped / constrained by layout");
+    return false;
+  }
+
+  if (!mPopupMoveToRectParams.mAnchorSet) {
+    LOG("  can't use move-to-rect due missing anchor");
+    return false;
+  }
+  // Update popup layout coordinates from layout by recent popup hierarchy
+  // (calculate correct position according to parent window)
+  // and convert to Gtk coordinates.
+  LayoutDeviceIntRect anchorRect = mPopupMoveToRectParams.mAnchorRect;
+  if (!WaylandPopupIsFirst()) {
+    GdkPoint parent = WaylandGetParentPosition();
+    LOG("  subtract parent position from anchor [%d, %d]\n", parent.x,
+        parent.y);
+    anchorRect.MoveBy(-GdkPointToDevicePixels(parent));
+  }
+
+  *aPopupAnchor = DevicePixelsToGdkRectRoundOut(anchorRect);
+  LOG("  anchored to rectangle [%d, %d] -> [%d x %d]", aPopupAnchor->x,
+      aPopupAnchor->y, aPopupAnchor->width, aPopupAnchor->height);
+
+  if (!WaylandPopupAnchorAdjustForParentPopup(aPopupAnchor, aOffset)) {
+    LOG("  can't use move-to-rect, anchor is not placed inside of parent "
+        "window");
+    return false;
+  }
+
+  return true;
+}
+
+void nsWindow::WaylandPopupPrepareForMove() {
+  LOG("nsWindow::WaylandPopupPrepareForMove()");
+
+  if (mPopupType == PopupType::Tooltip) {
+    // Don't fiddle with tooltips type, just hide it before move-to-rect
+    if (mPopupUseMoveToRect && gtk_widget_is_visible(mShell)) {
+      HideWaylandPopupWindow(/* aTemporaryHide */ true,
+                             /* aRemoveFromPopupList */ false);
+    }
+    LOG("  it's tooltip, quit");
+    return;
+  }
+
+  // See https://bugzilla.mozilla.org/show_bug.cgi?id=1785185#c8
+  // gtk_window_move() needs GDK_WINDOW_TYPE_HINT_UTILITY popup type.
+  // move-to-rect requires GDK_WINDOW_TYPE_HINT_POPUP_MENU popups type.
+  // We need to set it before map event when popup is hidden.
+  const GdkWindowTypeHint currentType =
+      gtk_window_get_type_hint(GTK_WINDOW(mShell));
+  const GdkWindowTypeHint requiredType = mPopupUseMoveToRect
+                                             ? GDK_WINDOW_TYPE_HINT_POPUP_MENU
+                                             : GDK_WINDOW_TYPE_HINT_UTILITY;
+
+  if (!mPopupUseMoveToRect && currentType == requiredType) {
+    LOG("  type matches and we're not forced to hide it, quit.");
+    return;
+  }
+
+  if (gtk_widget_is_visible(mShell)) {
+    HideWaylandPopupWindow(/* aTemporaryHide */ true,
+                           /* aRemoveFromPopupList */ false);
+  }
+
+  if (currentType != requiredType) {
+    LOG("  set type %s",
+        requiredType == GDK_WINDOW_TYPE_HINT_POPUP_MENU ? "MENU" : "UTILITY");
+    gtk_window_set_type_hint(GTK_WINDOW(mShell), requiredType);
+  }
+}
+
+// Plain popup move on Wayland - simply place popup on given location.
+// We can't just call gtk_window_move() as it's not effective on visible
+// popups.
+void nsWindow::WaylandPopupMovePlain(int aX, int aY) {
+  LOG("nsWindow::WaylandPopupMovePlain(%d, %d)", aX, aY);
+
+  // We can directly move only popups based on wl_subsurface type.
+  MOZ_DIAGNOSTIC_ASSERT(gtk_window_get_type_hint(GTK_WINDOW(mShell)) ==
+                            GDK_WINDOW_TYPE_HINT_UTILITY ||
+                        gtk_window_get_type_hint(GTK_WINDOW(mShell)) ==
+                            GDK_WINDOW_TYPE_HINT_TOOLTIP);
+
+  gtk_window_move(GTK_WINDOW(mShell), aX, aY);
+
+  // gtk_window_move() can trick us. When widget is hidden gtk_window_move()
+  // does not move the widget but sets new widget coordinates when widget
+  // is mapped again.
+  //
+  // If popup used move-to-rect before
+  // (GdkWindow has POSITION_METHOD_MOVE_TO_RECT set), popup will use
+  // move-to-rect again when it's mapped and we'll get bogus move-to-rect
+  // callback.
+  //
+  // gdk_window_move() sets position_method to POSITION_METHOD_MOVE_RESIZE
+  // so we'll use plain move when popup is shown.
+  if (!gtk_widget_get_mapped(mShell)) {
+    if (GdkWindow* window = GetToplevelGdkWindow()) {
+      gdk_window_move(window, aX, aY);
+    }
+  }
+}
+
+void nsWindow::WaylandPopupMoveImpl() {
+  // Available as of GTK 3.24+
+  static auto sGdkWindowMoveToRect = (void (*)(
+      GdkWindow*, const GdkRectangle*, GdkGravity, GdkGravity, GdkAnchorHints,
+      gint, gint))dlsym(RTLD_DEFAULT, "gdk_window_move_to_rect");
+
+  if (mPopupUseMoveToRect && !sGdkWindowMoveToRect) {
+    LOG("can't use move-to-rect due missing gdk_window_move_to_rect()");
+    mPopupUseMoveToRect = false;
+  }
+
+  GdkRectangle gtkAnchorRect;
+  GdkPoint offset;
+  if (mPopupUseMoveToRect) {
+    mPopupUseMoveToRect =
+        WaylandPopupCheckAndGetAnchor(&gtkAnchorRect, &offset);
+  }
+
+  LOG("nsWindow::WaylandPopupMove");
+  LOG("  original widget popup position [%d, %d]\n", mPopupPosition.x,
+      mPopupPosition.y);
+  LOG("  relative widget popup position [%d, %d]\n", mRelativePopupPosition.x,
+      mRelativePopupPosition.y);
+  LOG("  popup use move to rect %d", mPopupUseMoveToRect);
+
+  WaylandPopupPrepareForMove();
+
+  if (!mPopupUseMoveToRect) {
+    WaylandPopupMovePlain(mRelativePopupPosition.x, mRelativePopupPosition.y);
+    // Layout already should be aware of our bounds, since we didn't change it
+    // from the widget side for flipping or so.
+    return;
+  }
+
+  // Correct popup position now. It will be updated by gdk_window_move_to_rect()
+  // anyway but we need to set it now to avoid a race condition here.
+  WaylandPopupRemoveNegativePosition();
+
+  GdkWindow* gdkWindow = GetToplevelGdkWindow();
+  if (!g_signal_handler_find(gdkWindow, G_SIGNAL_MATCH_FUNC, 0, 0, nullptr,
+                             FuncToGpointer(NativeMoveResizeCallback), this)) {
+    g_signal_connect(gdkWindow, "moved-to-rect",
+                     G_CALLBACK(NativeMoveResizeCallback), this);
+  }
+  mWaitingForMoveToRectCallback = true;
+
+#ifdef MOZ_LOGGING
+  if (LOG_ENABLED()) {
+    LOG("  Call move-to-rect");
+    LOG("  Anchor rect [%d, %d] -> [%d x %d]", gtkAnchorRect.x, gtkAnchorRect.y,
+        gtkAnchorRect.width, gtkAnchorRect.height);
+    LOG("  Offset [%d, %d]", offset.x, offset.y);
+    LOG("  AnchorType");
+    LogPopupGravity(mPopupMoveToRectParams.mAnchorRectType);
+    LOG("  PopupAnchorType");
+    LogPopupGravity(mPopupMoveToRectParams.mPopupAnchorType);
+    LogPopupAnchorHints(mPopupMoveToRectParams.mHints);
+  }
+#endif
+
+  sGdkWindowMoveToRect(gdkWindow, &gtkAnchorRect,
+                       mPopupMoveToRectParams.mAnchorRectType,
+                       mPopupMoveToRectParams.mPopupAnchorType,
+                       mPopupMoveToRectParams.mHints, offset.x, offset.y);
+}
+
+void nsWindow::SetZIndex(int32_t aZIndex) {
+  nsIWidget* oldPrev = GetPrevSibling();
+
+  nsBaseWidget::SetZIndex(aZIndex);
+
+  if (GetPrevSibling() == oldPrev) {
+    return;
+  }
+
+  // We skip the nsWindows that don't have mGdkWindows.
+  // These are probably in the process of being destroyed.
+  if (!mGdkWindow) {
+    return;
+  }
+
+  if (!GetNextSibling()) {
+    // We're to be on top.
+    if (mGdkWindow) {
+      gdk_window_raise(mGdkWindow);
+    }
+  } else {
+    // All the siblings before us need to be below our widget.
+    for (nsWindow* w = this; w;
+         w = static_cast<nsWindow*>(w->GetPrevSibling())) {
+      if (w->mGdkWindow) {
+        gdk_window_lower(w->mGdkWindow);
+      }
+    }
+  }
+}
+
+void nsWindow::SetSizeMode(nsSizeMode aMode) {
+  LOG("nsWindow::SetSizeMode %d\n", aMode);
+
+  // Return if there's no shell or our current state is the same as the mode we
+  // were just set to.
+  if (!mShell) {
+    LOG("    no shell");
+    return;
+  }
+
+  if (mSizeMode == aMode && mLastSizeModeRequest == aMode) {
+    LOG("    already set");
+    return;
+  }
+
+  // It is tempting to try to optimize calls below based only on current
+  // mSizeMode, but that wouldn't work if there's a size-request in flight
+  // (specially before show). See bug 1789823.
+  const auto SizeModeMightBe = [&](nsSizeMode aModeToTest) {
+    if (mSizeMode != mLastSizeModeRequest) {
+      // Arbitrary size mode requests might be ongoing.
+      return true;
+    }
+    return mSizeMode == aModeToTest;
+  };
+
+  if (aMode != nsSizeMode_Fullscreen && aMode != nsSizeMode_Minimized) {
+    // Fullscreen and minimized are compatible.
+    if (SizeModeMightBe(nsSizeMode_Fullscreen)) {
+      MakeFullScreen(false);
+    }
+  }
+
+  switch (aMode) {
+    case nsSizeMode_Maximized:
+      LOG("    set maximized");
+      gtk_window_maximize(GTK_WINDOW(mShell));
+      break;
+    case nsSizeMode_Minimized:
+      LOG("    set minimized");
+      gtk_window_iconify(GTK_WINDOW(mShell));
+      break;
+    case nsSizeMode_Fullscreen:
+      LOG("    set fullscreen");
+      MakeFullScreen(true);
+      break;
+    default:
+      MOZ_FALLTHROUGH_ASSERT("Unknown size mode");
+    case nsSizeMode_Normal:
+      LOG("    set normal");
+      if (SizeModeMightBe(nsSizeMode_Maximized)) {
+        gtk_window_unmaximize(GTK_WINDOW(mShell));
+      }
+      if (SizeModeMightBe(nsSizeMode_Minimized)) {
+        gtk_window_deiconify(GTK_WINDOW(mShell));
+        // We need this for actual deiconification on mutter.
+        gtk_window_present(GTK_WINDOW(mShell));
+      }
+      break;
+  }
+  mLastSizeModeRequest = aMode;
+}
+
+#define kDesktopMutterSchema "org.gnome.mutter"_ns
+#define kDesktopDynamicWorkspacesKey "dynamic-workspaces"_ns
+
+static bool WorkspaceManagementDisabled(GdkScreen* screen) {
+  if (Preferences::GetBool("widget.disable-workspace-management", false)) {
+    return true;
+  }
+  if (Preferences::HasUserValue("widget.workspace-management")) {
+    return Preferences::GetBool("widget.workspace-management");
+  }
+
+  if (IsGnomeDesktopEnvironment()) {
+    // Gnome uses dynamic workspaces by default so disable workspace management
+    // in that case.
+    bool usesDynamicWorkspaces = true;
+    nsCOMPtr<nsIGSettingsService> gsettings =
+        do_GetService(NS_GSETTINGSSERVICE_CONTRACTID);
+    if (gsettings) {
+      nsCOMPtr<nsIGSettingsCollection> mutterSettings;
+      gsettings->GetCollectionForSchema(kDesktopMutterSchema,
+                                        getter_AddRefs(mutterSettings));
+      if (mutterSettings) {
+        mutterSettings->GetBoolean(kDesktopDynamicWorkspacesKey,
+                                   &usesDynamicWorkspaces);
+      }
+    }
+    return usesDynamicWorkspaces;
+  }
+
+  const auto& desktop = GetDesktopEnvironmentIdentifier();
+  return desktop.EqualsLiteral("bspwm") || desktop.EqualsLiteral("i3");
+}
+
+void nsWindow::GetWorkspaceID(nsAString& workspaceID) {
+  workspaceID.Truncate();
+
+  if (!GdkIsX11Display() || !mShell) {
+    return;
+  }
+
+#ifdef MOZ_X11
+  LOG("nsWindow::GetWorkspaceID()\n");
+
+  // Get the gdk window for this widget.
+  GdkWindow* gdk_window = GetToplevelGdkWindow();
+  if (!gdk_window) {
+    LOG("  missing Gdk window, quit.");
+    return;
+  }
+
+  if (WorkspaceManagementDisabled(gdk_window_get_screen(gdk_window))) {
+    LOG("  WorkspaceManagementDisabled, quit.");
+    return;
+  }
+
+  GdkAtom cardinal_atom = gdk_x11_xatom_to_atom(XA_CARDINAL);
+  GdkAtom type_returned;
+  int format_returned;
+  int length_returned;
+  long* wm_desktop;
+
+  if (!gdk_property_get(gdk_window, gdk_atom_intern("_NET_WM_DESKTOP", FALSE),
+                        cardinal_atom,
+                        0,          // offset
+                        INT32_MAX,  // length
+                        FALSE,      // delete
+                        &type_returned, &format_returned, &length_returned,
+                        (guchar**)&wm_desktop)) {
+    LOG("  gdk_property_get() failed, quit.");
+    return;
+  }
+
+  LOG("  got workspace ID %d", (int32_t)wm_desktop[0]);
+  workspaceID.AppendInt((int32_t)wm_desktop[0]);
+  g_free(wm_desktop);
+#endif
+}
+
+void nsWindow::MoveToWorkspace(const nsAString& workspaceIDStr) {
+  nsresult rv = NS_OK;
+  int32_t workspaceID = workspaceIDStr.ToInteger(&rv);
+
+  LOG("nsWindow::MoveToWorkspace() ID %d", workspaceID);
+  if (NS_FAILED(rv) || !workspaceID || !GdkIsX11Display() || !mShell) {
+    LOG("  MoveToWorkspace disabled, quit");
+    return;
+  }
+
+#ifdef MOZ_X11
+  // Get the gdk window for this widget.
+  GdkWindow* gdk_window = GetToplevelGdkWindow();
+  if (!gdk_window) {
+    LOG("  failed to get GdkWindow, quit.");
+    return;
+  }
+
+  // This code is inspired by some found in the 'gxtuner' project.
+  // https://github.com/brummer10/gxtuner/blob/792d453da0f3a599408008f0f1107823939d730d/deskpager.cpp#L50
+  XEvent xevent;
+  Display* xdisplay = gdk_x11_get_default_xdisplay();
+  GdkScreen* screen = gdk_window_get_screen(gdk_window);
+  Window root_win = GDK_WINDOW_XID(gdk_screen_get_root_window(screen));
+  GdkDisplay* display = gdk_window_get_display(gdk_window);
+  Atom type = gdk_x11_get_xatom_by_name_for_display(display, "_NET_WM_DESKTOP");
+
+  xevent.type = ClientMessage;
+  xevent.xclient.type = ClientMessage;
+  xevent.xclient.serial = 0;
+  xevent.xclient.send_event = TRUE;
+  xevent.xclient.display = xdisplay;
+  xevent.xclient.window = GDK_WINDOW_XID(gdk_window);
+  xevent.xclient.message_type = type;
+  xevent.xclient.format = 32;
+  xevent.xclient.data.l[0] = workspaceID;
+  xevent.xclient.data.l[1] = X11CurrentTime;
+  xevent.xclient.data.l[2] = 0;
+  xevent.xclient.data.l[3] = 0;
+  xevent.xclient.data.l[4] = 0;
+
+  XSendEvent(xdisplay, root_win, FALSE,
+             SubstructureNotifyMask | SubstructureRedirectMask, &xevent);
+
+  XFlush(xdisplay);
+  LOG("  moved to workspace");
+#endif
+}
+
+void nsWindow::SetUserTimeAndStartupTokenForActivatedWindow() {
+  nsGTKToolkit* toolkit = nsGTKToolkit::GetToolkit();
+  if (!toolkit || MOZ_UNLIKELY(mWindowType == WindowType::Invisible)) {
+    return;
+  }
+
+  mWindowActivationTokenFromEnv = toolkit->GetStartupToken();
+  if (!mWindowActivationTokenFromEnv.IsEmpty()) {
+    if (!GdkIsWaylandDisplay()) {
+      gtk_window_set_startup_id(GTK_WINDOW(mShell),
+                                mWindowActivationTokenFromEnv.get());
+      // In the case of X11, the above call is all we need. For wayland we need
+      // to keep the token around until we take it in
+      // TransferFocusToWaylandWindow.
+      mWindowActivationTokenFromEnv.Truncate();
+    }
+  } else if (uint32_t timestamp = toolkit->GetFocusTimestamp()) {
+    // We don't have the data we need. Fall back to an
+    // approximation ... using the timestamp of the remote command
+    // being received as a guess for the timestamp of the user event
+    // that triggered it.
+    gdk_window_focus(GetToplevelGdkWindow(), timestamp);
+  }
+
+  // If we used the startup ID, that already contains the focus timestamp;
+  // we don't want to reuse the timestamp next time we raise the window
+  toolkit->SetFocusTimestamp(0);
+  toolkit->SetStartupToken(""_ns);
+}
+
+/* static */
+guint32 nsWindow::GetLastUserInputTime() {
+  // gdk_x11_display_get_user_time/gtk_get_current_event_time tracks
+  // button and key presses, DESKTOP_STARTUP_ID used to start the app,
+  // drop events from external drags,
+  // WM_DELETE_WINDOW delete events, but not usually mouse motion nor
+  // button and key releases.  Therefore use the most recent of
+  // gdk_x11_display_get_user_time and the last time that we have seen.
+#ifdef MOZ_X11
+  GdkDisplay* gdkDisplay = gdk_display_get_default();
+  guint32 timestamp = GdkIsX11Display(gdkDisplay)
+                          ? gdk_x11_display_get_user_time(gdkDisplay)
+                          : gtk_get_current_event_time();
+#else
+  guint32 timestamp = gtk_get_current_event_time();
+#endif
+
+  if (sLastUserInputTime != GDK_CURRENT_TIME &&
+      TimestampIsNewerThan(sLastUserInputTime, timestamp)) {
+    return sLastUserInputTime;
+  }
+
+  return timestamp;
+}
+
+#ifdef MOZ_WAYLAND
+void nsWindow::FocusWaylandWindow(const char* aTokenID) {
+  MOZ_DIAGNOSTIC_ASSERT(aTokenID);
+
+  LOG("nsWindow::FocusWaylandWindow(%s)", aTokenID);
+  if (IsDestroyed()) {
+    LOG("  already destroyed, quit.");
+    return;
+  }
+  wl_surface* surface =
+      mGdkWindow ? gdk_wayland_window_get_wl_surface(mGdkWindow) : nullptr;
+  if (!surface) {
+    LOG("  mGdkWindow is not visible, quit.");
+    return;
+  }
+
+  LOG("  requesting xdg-activation, surface ID %d",
+      wl_proxy_get_id((struct wl_proxy*)surface));
+  xdg_activation_v1* xdg_activation = WaylandDisplayGet()->GetXdgActivation();
+  if (!xdg_activation) {
+    return;
+  }
+  xdg_activation_v1_activate(xdg_activation, aTokenID, surface);
+}
+
+// Transfer focus from gFocusWindow to aWindow and use xdg_activation
+// protocol for it.
+void nsWindow::TransferFocusToWaylandWindow(nsWindow* aWindow) {
+  LOGW("nsWindow::TransferFocusToWaylandWindow(%p) gFocusWindow %p", aWindow,
+       gFocusWindow);
+  auto promise = mozilla::widget::RequestWaylandFocusPromise();
+  if (NS_WARN_IF(!promise)) {
+    LOGW("  quit, failed to create TransferFocusToWaylandWindow [%p]", aWindow);
+    return;
+  }
+  promise->Then(
+      GetMainThreadSerialEventTarget(), __func__,
+      /* resolve */
+      [window = RefPtr{aWindow}](nsCString token) {
+        window->FocusWaylandWindow(token.get());
+      },
+      /* reject */
+      [window = RefPtr{aWindow}](bool state) {
+        LOGW("TransferFocusToWaylandWindow [%p] failed", window.get());
+      });
+}
+#endif
+
+// Request activation of this window or give focus to this widget.
+// aRaise means whether we should request activation of this widget's
+// toplevel window.
+//
+// nsWindow::SetFocus(Raise::Yes) - Raise and give focus to toplevel window.
+// nsWindow::SetFocus(Raise::No) - Give focus to this window.
+void nsWindow::SetFocus(Raise aRaise, mozilla::dom::CallerType aCallerType) {
+  LOG("nsWindow::SetFocus Raise %d\n", aRaise == Raise::Yes);
+
+  // Raise the window if someone passed in true and the prefs are
+  // set properly.
+  GtkWidget* toplevelWidget = gtk_widget_get_toplevel(GTK_WIDGET(mContainer));
+
+  LOG("  gFocusWindow [%p]\n", gFocusWindow);
+  LOG("  mContainer [%p]\n", GTK_WIDGET(mContainer));
+  LOG("  Toplevel widget [%p]\n", toplevelWidget);
+
+  // Make sure that our owning widget has focus.  If it doesn't try to
+  // grab it.  Note that we don't set our focus flag in this case.
+  if (StaticPrefs::mozilla_widget_raise_on_setfocus_AtStartup() &&
+      aRaise == Raise::Yes && toplevelWidget &&
+      !gtk_widget_has_focus(toplevelWidget)) {
+    if (gtk_widget_get_visible(mShell)) {
+      LOG("  toplevel is not focused");
+      gdk_window_show_unraised(GetToplevelGdkWindow());
+      // Unset the urgency hint if possible.
+      SetUrgencyHint(mShell, false);
+    }
+  }
+
+  RefPtr<nsWindow> toplevelWindow = get_window_for_gtk_widget(toplevelWidget);
+  if (!toplevelWindow) {
+    LOG("  missing toplevel nsWindow, quit\n");
+    return;
+  }
+
+  if (aRaise == Raise::Yes) {
+    // means request toplevel activation.
+
+    // This is asynchronous. If and when the window manager accepts the request,
+    // then the focus widget will get a focus-in-event signal.
+    if (StaticPrefs::mozilla_widget_raise_on_setfocus_AtStartup() &&
+        toplevelWindow->mIsShown && toplevelWindow->mShell &&
+        !gtk_window_is_active(GTK_WINDOW(toplevelWindow->mShell))) {
+      LOG("  toplevel is visible but not active, requesting activation [%p]",
+          toplevelWindow.get());
+
+      // Take the time here explicitly for the call below.
+      const uint32_t timestamp = [&] {
+        if (nsGTKToolkit* toolkit = nsGTKToolkit::GetToolkit()) {
+          if (uint32_t t = toolkit->GetFocusTimestamp()) {
+            toolkit->SetFocusTimestamp(0);
+            return t;
+          }
+        }
+        return GetLastUserInputTime();
+      }();
+
+      toplevelWindow->SetUserTimeAndStartupTokenForActivatedWindow();
+      gtk_window_present_with_time(GTK_WINDOW(toplevelWindow->mShell),
+                                   timestamp);
+
+#ifdef MOZ_WAYLAND
+      if (GdkIsWaylandDisplay()) {
+        auto existingToken =
+            std::move(toplevelWindow->mWindowActivationTokenFromEnv);
+        if (!existingToken.IsEmpty()) {
+          LOG("  has existing activation token.");
+          toplevelWindow->FocusWaylandWindow(existingToken.get());
+        } else {
+          LOG("  missing activation token, try to transfer from focused "
+              "window");
+          TransferFocusToWaylandWindow(toplevelWindow);
+        }
+      }
+#endif
+    }
+    return;
+  }
+
+  // aRaise == No means that keyboard events should be dispatched from this
+  // widget.
+
+  // Ensure GTK_WIDGET(mContainer) is the focused GtkWidget within its toplevel
+  // window.
+  //
+  // For WindowType::Popup, this GtkWidget may not actually be the one that
+  // receives the key events as it may be the parent window that is active.
+  if (!gtk_widget_is_focus(GTK_WIDGET(mContainer))) {
+    // This is synchronous.  It takes focus from a plugin or from a widget
+    // in an embedder.  The focus manager already knows that this window
+    // is active so gBlockActivateEvent avoids another (unnecessary)
+    // activate notification.
+    gBlockActivateEvent = true;
+    gtk_widget_grab_focus(GTK_WIDGET(mContainer));
+    gBlockActivateEvent = false;
+  }
+
+  // If this is the widget that already has focus, return.
+  if (gFocusWindow == this) {
+    LOG("  already have focus");
+    return;
+  }
+
+  // Set this window to be the focused child window
+  gFocusWindow = this;
+
+  if (mIMContext) {
+    mIMContext->OnFocusWindow(this);
+  }
+
+  LOG("  widget now has focus in SetFocus()");
+}
+
+LayoutDeviceIntRect nsWindow::GetScreenBounds() {
+  if (!mGdkWindow) {
+    return mBounds;
+  }
+
+  const LayoutDeviceIntPoint origin = [&] {
+    gint x, y;
+    gdk_window_get_root_origin(mGdkWindow, &x, &y);
+
+    // Workaround for https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/4820
+    // Bug 1775017 Gtk < 3.24.35 returns scaled values for
+    // override redirected window on X11.
+    if (gtk_check_version(3, 24, 35) != nullptr && GdkIsX11Display() &&
+        gdk_window_get_window_type(mGdkWindow) == GDK_WINDOW_TEMP) {
+      return LayoutDeviceIntPoint(x, y);
+    }
+    return GdkPointToDevicePixels({x, y});
+  }();
+
+  // mBounds.Size() is the window bounds, not the window-manager frame
+  // bounds (bug 581863).  gdk_window_get_frame_extents would give the
+  // frame bounds, but mBounds.Size() is returned here for consistency
+  // with Resize.
+  const LayoutDeviceIntRect rect(origin, mBounds.Size());
+#if MOZ_LOGGING
+  if (MOZ_LOG_TEST(IsPopup() ? gWidgetPopupLog : gWidgetLog,
+                   LogLevel::Verbose)) {
+    gint scale = GdkCeiledScaleFactor();
+    if (mLastLoggedScale != scale || !(mLastLoggedBoundSize == rect)) {
+      mLastLoggedScale = scale;
+      mLastLoggedBoundSize = rect;
+      LOG("GetScreenBounds %d,%d -> %d x %d, unscaled %d,%d -> %d x %d\n",
+          rect.x, rect.y, rect.width, rect.height, rect.x / scale,
+          rect.y / scale, rect.width / scale, rect.height / scale);
+    }
+  }
+#endif
+  return rect;
+}
+
+LayoutDeviceIntSize nsWindow::GetClientSize() {
+  return LayoutDeviceIntSize(mBounds.width, mBounds.height);
+}
+
+LayoutDeviceIntRect nsWindow::GetClientBounds() {
+  // GetBounds returns a rect whose top left represents the top left of the
+  // outer bounds, but whose width/height represent the size of the inner
+  // bounds (which is messed up).
+  LayoutDeviceIntRect rect = GetBounds();
+  rect.MoveBy(GetClientOffset());
+  return rect;
+}
+
+void nsWindow::RecomputeClientOffset(bool aNotify) {
+  if (!IsTopLevelWindowType()) {
+    return;
+  }
+
+  auto oldOffset = mClientOffset;
+
+  mClientOffset = WidgetToScreenOffset() - mBounds.TopLeft();
+
+  if (aNotify && mClientOffset != oldOffset) {
+    // Send a WindowMoved notification. This ensures that BrowserParent picks up
+    // the new client offset and sends it to the child process if appropriate.
+    NotifyWindowMoved(mBounds.x, mBounds.y);
+  }
+}
+
+gboolean nsWindow::OnPropertyNotifyEvent(GtkWidget* aWidget,
+                                         GdkEventProperty* aEvent) {
+  if (aEvent->atom == gdk_atom_intern("_NET_FRAME_EXTENTS", FALSE)) {
+    RecomputeClientOffset(/* aNotify = */ true);
+    return FALSE;
+  }
+  if (!mGdkWindow) {
+    return FALSE;
+  }
+#ifdef MOZ_X11
+  if (GetCurrentTimeGetter()->PropertyNotifyHandler(aWidget, aEvent)) {
+    return TRUE;
+  }
+#endif
+  return FALSE;
+}
+
+static GdkCursor* GetCursorForImage(const nsIWidget::Cursor& aCursor,
+                                    int32_t aWidgetScaleFactor) {
+  if (!aCursor.IsCustom()) {
+    return nullptr;
+  }
+  nsIntSize size = nsIWidget::CustomCursorSize(aCursor);
+
+  // NOTE: GTK only allows integer scale factors, so we ceil to the larger scale
+  // factor and then tell gtk to scale it down. We ensure to scale at least to
+  // the GDK scale factor, so that cursors aren't downsized in HiDPI on wayland,
+  // see bug 1707533.
+  int32_t gtkScale = std::max(
+      aWidgetScaleFactor, int32_t(std::ceil(std::max(aCursor.mResolution.mX,
+                                                     aCursor.mResolution.mY))));
+
+  // Reject cursors greater than 128 pixels in some direction, to prevent
+  // spoofing.
+  // XXX ideally we should rescale. Also, we could modify the API to
+  // allow trusted content to set larger cursors.
+  //
+  // TODO(emilio, bug 1445844): Unify the solution for this with other
+  // platforms.
+  if (size.width > 128 || size.height > 128) {
+    return nullptr;
+  }
+
+  nsIntSize rasterSize = size * gtkScale;
+  RefPtr<GdkPixbuf> pixbuf =
+      nsImageToPixbuf::ImageToPixbuf(aCursor.mContainer, Some(rasterSize));
+  if (!pixbuf) {
+    return nullptr;
+  }
+
+  // Looks like all cursors need an alpha channel (tested on Gtk 2.4.4). This
+  // is of course not documented anywhere...
+  // So add one if there isn't one yet
+  if (!gdk_pixbuf_get_has_alpha(pixbuf)) {
+    RefPtr<GdkPixbuf> alphaBuf =
+        dont_AddRef(gdk_pixbuf_add_alpha(pixbuf, FALSE, 0, 0, 0));
+    pixbuf = std::move(alphaBuf);
+    if (!pixbuf) {
+      return nullptr;
+    }
+  }
+
+  cairo_surface_t* surface =
+      gdk_cairo_surface_create_from_pixbuf(pixbuf, gtkScale, nullptr);
+  if (!surface) {
+    return nullptr;
+  }
+
+  auto CleanupSurface =
+      MakeScopeExit([&]() { cairo_surface_destroy(surface); });
+
+  return gdk_cursor_new_from_surface(gdk_display_get_default(), surface,
+                                     aCursor.mHotspotX, aCursor.mHotspotY);
+}
+
+void nsWindow::SetCursor(const Cursor& aCursor) {
+  if (mWidgetCursorLocked || !mGdkWindow) {
+    return;
+  }
+
+  // Only change cursor if it's actually been changed
+  if (!mUpdateCursor && mCursor == aCursor) {
+    return;
+  }
+
+  mUpdateCursor = false;
+  mCursor = aCursor;
+
+  // Try to set the cursor image first, and fall back to the numeric cursor.
+  GdkCursor* imageCursor = nullptr;
+  if (mCustomCursorAllowed) {
+    imageCursor = GetCursorForImage(aCursor, GdkCeiledScaleFactor());
+  }
+
+  // When using a custom cursor, clear the cursor first using eCursor_none, in
+  // order to work around https://gitlab.gnome.org/GNOME/gtk/-/issues/6242
+  GdkCursor* nonImageCursor =
+      get_gtk_cursor(imageCursor ? eCursor_none : aCursor.mDefaultCursor);
+  auto CleanupCursor = mozilla::MakeScopeExit([&]() {
+    // get_gtk_cursor returns a weak reference, which we shouldn't unref.
+    if (imageCursor) {
+      g_object_unref(imageCursor);
+    }
+  });
+
+  gdk_window_set_cursor(mGdkWindow, nonImageCursor);
+  if (imageCursor) {
+    gdk_window_set_cursor(mGdkWindow, imageCursor);
+  }
+}
+
+void nsWindow::Invalidate(const LayoutDeviceIntRect& aRect) {
+  if (!mGdkWindow) {
+    return;
+  }
+
+  GdkRectangle rect = DevicePixelsToGdkRectRoundOut(aRect);
+  gdk_window_invalidate_rect(mGdkWindow, &rect, FALSE);
+
+  LOG("Invalidate (rect): %d %d %d %d\n", rect.x, rect.y, rect.width,
+      rect.height);
+}
+
+void* nsWindow::GetNativeData(uint32_t aDataType) {
+  switch (aDataType) {
+    case NS_NATIVE_WINDOW:
+    case NS_NATIVE_WIDGET: {
+      return mGdkWindow;
+    }
+
+    case NS_NATIVE_SHELLWIDGET:
+      return GetToplevelWidget();
+
+    case NS_NATIVE_WINDOW_WEBRTC_DEVICE_ID:
+      if (!mGdkWindow) {
+        return nullptr;
+      }
+#ifdef MOZ_X11
+      if (GdkIsX11Display()) {
+        return (void*)GDK_WINDOW_XID(gdk_window_get_toplevel(mGdkWindow));
+      }
+#endif
+      NS_WARNING(
+          "nsWindow::GetNativeData(): NS_NATIVE_WINDOW_WEBRTC_DEVICE_ID is not "
+          "handled on Wayland!");
+      return nullptr;
+    case NS_RAW_NATIVE_IME_CONTEXT: {
+      void* pseudoIMEContext = GetPseudoIMEContext();
+      if (pseudoIMEContext) {
+        return pseudoIMEContext;
+      }
+      // If IME context isn't available on this widget, we should set |this|
+      // instead of nullptr.
+      if (!mIMContext) {
+        return this;
+      }
+      return mIMContext.get();
+    }
+    case NS_NATIVE_OPENGL_CONTEXT:
+      return nullptr;
+    case NS_NATIVE_EGL_WINDOW: {
+      void* eglWindow = nullptr;
+
+      // We can't block on mutex here as it leads to a deadlock:
+      // 1) mutex is taken at nsWindow::Destroy()
+      // 2) NS_NATIVE_EGL_WINDOW is called from compositor/rendering thread,
+      //    blocking on mutex.
+      // 3) DestroyCompositor() is called by nsWindow::Destroy(). As a sync
+      //    call it waits to compositor/rendering threads,
+      //    but they're blocked at 2).
+      //    It's fine if we return null EGL window during DestroyCompositor(),
+      //    in such case compositor painting is skipped.
+      if (mDestroyMutex.TryLock()) {
+        if (mGdkWindow && !mIsDestroyed) {
+#ifdef MOZ_X11
+          if (GdkIsX11Display()) {
+            eglWindow = (void*)GDK_WINDOW_XID(mGdkWindow);
+          }
+#endif
+#ifdef MOZ_WAYLAND
+          if (GdkIsWaylandDisplay()) {
+            bool hiddenWindow =
+                mCompositorWidgetDelegate &&
+                mCompositorWidgetDelegate->AsGtkCompositorWidget() &&
+                mCompositorWidgetDelegate->AsGtkCompositorWidget()->IsHidden();
+            if (!hiddenWindow) {
+              eglWindow = moz_container_wayland_get_egl_window(
+                  mContainer, FractionalScaleFactor());
+            }
+          }
+#endif
+        }
+        mDestroyMutex.Unlock();
+      }
+
+      LOG("Get NS_NATIVE_EGL_WINDOW mGdkWindow %p returned eglWindow %p",
+          mGdkWindow, eglWindow);
+      return eglWindow;
+    }
+    default:
+      NS_WARNING("nsWindow::GetNativeData called with bad value");
+      return nullptr;
+  }
+}
+
+nsresult nsWindow::SetTitle(const nsAString& aTitle) {
+  if (!mShell) {
+    return NS_OK;
+  }
+
+  // convert the string into utf8 and set the title.
+#define UTF8_FOLLOWBYTE(ch) (((ch) & 0xC0) == 0x80)
+  NS_ConvertUTF16toUTF8 titleUTF8(aTitle);
+  if (titleUTF8.Length() > NS_WINDOW_TITLE_MAX_LENGTH) {
+    // Truncate overlong titles (bug 167315). Make sure we chop after a
+    // complete sequence by making sure the next char isn't a follow-byte.
+    uint32_t len = NS_WINDOW_TITLE_MAX_LENGTH;
+    while (UTF8_FOLLOWBYTE(titleUTF8[len])) --len;
+    titleUTF8.Truncate(len);
+  }
+  gtk_window_set_title(GTK_WINDOW(mShell), (const char*)titleUTF8.get());
+
+  return NS_OK;
+}
+
+void nsWindow::SetIcon(const nsAString& aIconSpec) {
+  if (!mShell) {
+    return;
+  }
+
+  nsAutoCString iconName;
+
+  if (aIconSpec.EqualsLiteral("default")) {
+    nsAutoString brandName;
+    WidgetUtils::GetBrandShortName(brandName);
+    if (brandName.IsEmpty()) {
+      brandName.AssignLiteral(u"Mozilla");
+    }
+    AppendUTF16toUTF8(brandName, iconName);
+    ToLowerCase(iconName);
+  } else {
+    AppendUTF16toUTF8(aIconSpec, iconName);
+  }
+
+  nsCOMPtr<nsIFile> iconFile;
+  nsAutoCString path;
+
+  gint* iconSizes = gtk_icon_theme_get_icon_sizes(gtk_icon_theme_get_default(),
+                                                  iconName.get());
+  bool foundIcon = (iconSizes[0] != 0);
+  g_free(iconSizes);
+
+  if (!foundIcon) {
+    // Look for icons with the following suffixes appended to the base name
+    // The last two entries (for the old XPM format) will be ignored unless
+    // no icons are found using other suffixes. XPM icons are deprecated.
+
+    const char16_t extensions[9][8] = {u".png",    u"16.png", u"32.png",
+                                       u"48.png",  u"64.png", u"128.png",
+                                       u"256.png", u".xpm",   u"16.xpm"};
+
+    for (uint32_t i = 0; i < ArrayLength(extensions); i++) {
+      // Don't bother looking for XPM versions if we found a PNG.
+      if (i == ArrayLength(extensions) - 2 && foundIcon) break;
+
+      ResolveIconName(aIconSpec, nsDependentString(extensions[i]),
+                      getter_AddRefs(iconFile));
+      if (iconFile) {
+        iconFile->GetNativePath(path);
+        GdkPixbuf* icon = gdk_pixbuf_new_from_file(path.get(), nullptr);
+        if (icon) {
+          gtk_icon_theme_add_builtin_icon(iconName.get(),
+                                          gdk_pixbuf_get_height(icon), icon);
+          g_object_unref(icon);
+          foundIcon = true;
+        }
+      }
+    }
+  }
+
+  // leave the default icon intact if no matching icons were found
+  if (foundIcon) {
+    gtk_window_set_icon_name(GTK_WINDOW(mShell), iconName.get());
+  }
+}
+
+/* TODO(bug 1655924): gdk_window_get_origin is can block waiting for the X
+   server for a long time, we would like to use the implementation below
+   instead. However, removing the synchronous x server queries causes a race
+   condition to surface, causing issues such as bug 1652743 and bug 1653711.
+
+
+   This code can be used instead of gdk_window_get_origin() but it cuases
+   such issues:
+
+    *aX = 0;
+    *aY = 0;
+    if (!aWindow) {
+      return;
+    }
+
+    GdkWindow* current = aWindow;
+    while (GdkWindow* parent = gdk_window_get_parent(current)) {
+      if (parent == current) {
+        break;
+      }
+
+      int x = 0;
+      int y = 0;
+      gdk_window_get_position(current, &x, &y);
+      *aX += x;
+      *aY += y;
+
+      current = parent;
+    }
+*/
+LayoutDeviceIntPoint nsWindow::WidgetToScreenOffset() {
+  // Don't use gdk_window_get_origin() on wl_subsurface Wayland popups
+  // https://gitlab.gnome.org/GNOME/gtk/-/issues/5287
+  if (IsWaylandPopup() && !mPopupUseMoveToRect) {
+    return mBounds.TopLeft();
+  }
+  nsIntPoint origin(0, 0);
+  if (mGdkWindow) {
+    gdk_window_get_origin(mGdkWindow, &origin.x.value, &origin.y.value);
+  }
+  return GdkPointToDevicePixels({origin.x, origin.y});
+}
+
+void nsWindow::CaptureRollupEvents(bool aDoCapture) {
+  LOG("CaptureRollupEvents(%d)\n", aDoCapture);
+  if (mIsDestroyed) {
+    return;
+  }
+
+  static constexpr auto kCaptureEventsMask =
+      GdkEventMask(GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK |
+                   GDK_POINTER_MOTION_MASK | GDK_TOUCH_MASK);
+
+  static bool sSystemNeedsPointerGrab = [&] {
+    if (GdkIsWaylandDisplay()) {
+      return false;
+    }
+    // We only need to grab the pointer for X servers that move the focus with
+    // the pointer (like twm, sawfish...). Since we roll up popups on focus out,
+    // not grabbing the pointer triggers rollup when the mouse enters the popup
+    // and leaves the main window, see bug 1807482.
+    //
+    // FVWM is also affected but less severely: the pointer can enter the
+    // popup, but if it briefly moves out of the popup and over the main window
+    // then we see a focus change and roll up the popup.
+    //
+    // We don't do it for most common desktops, if only because it causes X11
+    // crashes like bug 1607713.
+    const auto& desktop = GetDesktopEnvironmentIdentifier();
+    return desktop.EqualsLiteral("twm") || desktop.EqualsLiteral("sawfish") ||
+           StringBeginsWith(desktop, "fvwm"_ns);
+  }();
+
+  const bool grabPointer = [] {
+    switch (StaticPrefs::widget_gtk_grab_pointer()) {
+      case 0:
+        return false;
+      case 1:
+        return true;
+      default:
+        return sSystemNeedsPointerGrab;
+    }
+  }();
+
+  if (!grabPointer) {
+    return;
+  }
+
+  mNeedsToRetryCapturingMouse = false;
+  if (aDoCapture) {
+    if (mIsDragPopup || DragInProgress()) {
+      // Don't add a grab if a drag is in progress, or if the widget is a drag
+      // feedback popup. (panels with type="drag").
+      return;
+    }
+
+    if (!mHasMappedToplevel) {
+      // On X, capturing an unmapped window is pointless (returns
+      // GDK_GRAB_NOT_VIEWABLE). Avoid the X server round-trip and just retry
+      // when we're mapped.
+      mNeedsToRetryCapturingMouse = true;
+      return;
+    }
+
+    // gdk_pointer_grab is deprecated in favor of gdk_device_grab, but that
+    // causes a strange bug on X11, most obviously with nested popup menus:
+    // we somehow take the pointer position relative to the top left of the
+    // outer menu and use it as if it were relative to the submenu.  This
+    // doesn't happen with gdk_pointer_grab even though the code is very
+    // similar.  See the video attached to bug 1750721 for a demonstration,
+    // and see also bug 1820542 for when the same thing happened with
+    // another attempt to use gdk_device_grab.
+    //
+    // (gdk_device_grab is deprecated in favor of gdk_seat_grab as of 3.20,
+    // but at the time of this writing we still support older versions of
+    // GTK 3.)
+    GdkGrabStatus status =
+        gdk_pointer_grab(GetToplevelGdkWindow(),
+                         /* owner_events = */ true, kCaptureEventsMask,
+                         /* confine_to = */ nullptr,
+                         /* cursor = */ nullptr, GetLastUserInputTime());
+    Unused << NS_WARN_IF(status != GDK_GRAB_SUCCESS);
+    LOG(" > pointer grab with status %d", int(status));
+    gtk_grab_add(GTK_WIDGET(mContainer));
+  } else {
+    // There may not have been a drag in process when aDoCapture was set,
+    // so make sure to remove any added grab.  This is a no-op if the grab
+    // was not added to this widget.
+    gtk_grab_remove(GTK_WIDGET(mContainer));
+    gdk_pointer_ungrab(GetLastUserInputTime());
+  }
+}
+
+nsresult nsWindow::GetAttention(int32_t aCycleCount) {
+  LOG("nsWindow::GetAttention");
+
+  GtkWidget* top_window = GetToplevelWidget();
+  GtkWidget* top_focused_window =
+      gFocusWindow ? gFocusWindow->GetToplevelWidget() : nullptr;
+
+  // Don't get attention if the window is focused anyway.
+  if (top_window && (gtk_widget_get_visible(top_window)) &&
+      top_window != top_focused_window) {
+    SetUrgencyHint(top_window, true);
+  }
+
+  return NS_OK;
+}
+
+bool nsWindow::HasPendingInputEvent() {
+  // This sucks, but gtk/gdk has no way to answer the question we want while
+  // excluding paint events, and there's no X API that will let us peek
+  // without blocking or removing.  To prevent event reordering, peek
+  // anything except expose events.  Reordering expose and others should be
+  // ok, hopefully.
+  bool haveEvent = false;
+#ifdef MOZ_X11
+  XEvent ev;
+  if (GdkIsX11Display()) {
+    Display* display = GDK_DISPLAY_XDISPLAY(gdk_display_get_default());
+    haveEvent = XCheckMaskEvent(
+        display,
+        KeyPressMask | KeyReleaseMask | ButtonPressMask | ButtonReleaseMask |
+            EnterWindowMask | LeaveWindowMask | PointerMotionMask |
+            PointerMotionHintMask | Button1MotionMask | Button2MotionMask |
+            Button3MotionMask | Button4MotionMask | Button5MotionMask |
+            ButtonMotionMask | KeymapStateMask | VisibilityChangeMask |
+            StructureNotifyMask | ResizeRedirectMask | SubstructureNotifyMask |
+            SubstructureRedirectMask | FocusChangeMask | PropertyChangeMask |
+            ColormapChangeMask | OwnerGrabButtonMask,
+        &ev);
+    if (haveEvent) {
+      XPutBackEvent(display, &ev);
+    }
+  }
+#endif
+  return haveEvent;
+}
+
+#ifdef cairo_copy_clip_rectangle_list
+#  error "Looks like we're including Mozilla's cairo instead of system cairo"
+#endif
+static bool ExtractExposeRegion(LayoutDeviceIntRegion& aRegion, cairo_t* cr) {
+  cairo_rectangle_list_t* rects = cairo_copy_clip_rectangle_list(cr);
+  if (rects->status != CAIRO_STATUS_SUCCESS) {
+    NS_WARNING("Failed to obtain cairo rectangle list.");
+    return false;
+  }
+
+  for (int i = 0; i < rects->num_rectangles; i++) {
+    const cairo_rectangle_t& r = rects->rectangles[i];
+    aRegion.Or(aRegion,
+               LayoutDeviceIntRect::Truncate((float)r.x, (float)r.y,
+                                             (float)r.width, (float)r.height));
+  }
+
+  cairo_rectangle_list_destroy(rects);
+  return true;
+}
+
+#ifdef MOZ_WAYLAND
+void nsWindow::CreateCompositorVsyncDispatcher() {
+  LOG_VSYNC("nsWindow::CreateCompositorVsyncDispatcher()");
+  if (!mWaylandVsyncSource) {
+    LOG_VSYNC(
+        "  mWaylandVsyncSource is missing, create "
+        "nsBaseWidget::CompositorVsyncDispatcher()");
+    nsBaseWidget::CreateCompositorVsyncDispatcher();
+    return;
+  }
+  if (!mCompositorVsyncDispatcherLock) {
+    mCompositorVsyncDispatcherLock =
+        MakeUnique<Mutex>("mCompositorVsyncDispatcherLock");
+  }
+  MutexAutoLock lock(*mCompositorVsyncDispatcherLock);
+  if (!mCompositorVsyncDispatcher) {
+    LOG_VSYNC("  create CompositorVsyncDispatcher()");
+    mCompositorVsyncDispatcher =
+        new CompositorVsyncDispatcher(mWaylandVsyncDispatcher);
+  }
+}
+#endif
+
+void nsWindow::RequestRepaint(LayoutDeviceIntRegion& aRepaintRegion) {
+  WindowRenderer* renderer = GetWindowRenderer();
+  WebRenderLayerManager* layerManager = renderer->AsWebRender();
+  KnowsCompositor* knowsCompositor = renderer->AsKnowsCompositor();
+
+  if (knowsCompositor && layerManager && mCompositorSession) {
+    if (!mConfiguredClearColor && !IsPopup()) {
+      layerManager->WrBridge()->SendSetDefaultClearColor(LookAndFeel::Color(
+          LookAndFeel::ColorID::Window, PreferenceSheet::ColorSchemeForChrome(),
+          LookAndFeel::UseStandins::No));
+      mConfiguredClearColor = true;
+    }
+
+    // We need to paint to the screen even if nothing changed, since if we
+    // don't have a compositing window manager, our pixels could be stale.
+    layerManager->SetNeedsComposite(true);
+    layerManager->SendInvalidRegion(aRepaintRegion.ToUnknownRegion());
+  }
+}
+
+gboolean nsWindow::OnExposeEvent(cairo_t* cr) {
+  // This might destroy us.
+  NotifyOcclusionState(OcclusionState::VISIBLE);
+  if (mIsDestroyed) {
+    return FALSE;
+  }
+
+  // Send any pending resize events so that layout can update.
+  // May run event loop and destroy us.
+  MaybeDispatchResized();
+  if (mIsDestroyed) {
+    return FALSE;
+  }
+
+  // Windows that are not visible will be painted after they become visible.
+  if (!mGdkWindow || !mHasMappedToplevel) {
+    return FALSE;
+  }
+#ifdef MOZ_WAYLAND
+  if (GdkIsWaylandDisplay() && !moz_container_wayland_can_draw(mContainer)) {
+    return FALSE;
+  }
+#endif
+
+  if (!GetListener()) {
+    return FALSE;
+  }
+
+  LOG("nsWindow::OnExposeEvent GdkWindow [%p] XID [0x%lx]", mGdkWindow,
+      GetX11Window());
+
+  LayoutDeviceIntRegion exposeRegion;
+  if (!ExtractExposeRegion(exposeRegion, cr)) {
+    LOG("  no rects, quit");
+    return FALSE;
+  }
+
+  gint scale = GdkCeiledScaleFactor();
+  LayoutDeviceIntRegion region = exposeRegion;
+  region.ScaleRoundOut(scale, scale);
+
+  RequestRepaint(region);
+
+  RefPtr<nsWindow> strongThis(this);
+
+  // Dispatch WillPaintWindow notification to allow scripts etc. to run
+  // before we paint. It also spins event loop which may show/hide the window
+  // so we may have new renderer etc.
+  GetListener()->WillPaintWindow(this);
+
+  // If the window has been destroyed during the will paint notification,
+  // there is nothing left to do.
+  if (!mGdkWindow || mIsDestroyed) {
+    return TRUE;
+  }
+
+  // Re-get all rendering components since the will paint notification
+  // might have killed it.
+  nsIWidgetListener* listener = GetListener();
+  if (!listener) return FALSE;
+
+  WindowRenderer* renderer = GetWindowRenderer();
+  WebRenderLayerManager* layerManager = renderer->AsWebRender();
+  KnowsCompositor* knowsCompositor = renderer->AsKnowsCompositor();
+
+  if (knowsCompositor && layerManager && layerManager->NeedsComposite()) {
+    layerManager->ScheduleComposite(wr::RenderReasons::WIDGET);
+    layerManager->SetNeedsComposite(false);
+  }
+
+  // Our bounds may have changed after calling WillPaintWindow.  Clip
+  // to the new bounds here.  The region is relative to this
+  // window.
+  region.And(region, LayoutDeviceIntRect(0, 0, mBounds.width, mBounds.height));
+
+  bool shaped = false;
+  if (TransparencyMode::Transparent == GetTransparencyMode()) {
+    auto* window = static_cast<nsWindow*>(GetTopLevelWidget());
+    if (mTransparencyBitmapForTitlebar) {
+      if (mSizeMode == nsSizeMode_Normal) {
+        window->UpdateTitlebarTransparencyBitmap();
+      } else {
+        window->ClearTransparencyBitmap();
+      }
+    } else {
+      if (mHasAlphaVisual) {
+        // Remove possible shape mask from when window manger was not
+        // previously compositing.
+        window->ClearTransparencyBitmap();
+      } else {
+        shaped = true;
+      }
+    }
+  }
+
+  if (region.IsEmpty()) {
+    return TRUE;
+  }
+
+  // If this widget uses OMTC...
+  if (renderer->GetBackendType() == LayersBackend::LAYERS_WR) {
+    listener->PaintWindow(this, region);
+
+    // Re-get the listener since the will paint notification might have
+    // killed it.
+    listener = GetListener();
+    if (!listener) {
+      return TRUE;
+    }
+
+    listener->DidPaintWindow();
+    return TRUE;
+  }
+
+  BufferMode layerBuffering = BufferMode::BUFFERED;
+  RefPtr<DrawTarget> dt = StartRemoteDrawingInRegion(region, &layerBuffering);
+  if (!dt || !dt->IsValid()) {
+    return FALSE;
+  }
+  Maybe<gfxContext> ctx;
+  IntRect boundsRect = region.GetBounds().ToUnknownRect();
+  IntPoint offset(0, 0);
+  if (dt->GetSize() == boundsRect.Size()) {
+    offset = boundsRect.TopLeft();
+    dt->SetTransform(Matrix::Translation(-offset));
+  }
+
+#ifdef MOZ_X11
+  if (shaped) {
+    // Collapse update area to the bounding box. This is so we only have to
+    // call UpdateTranslucentWindowAlpha once. After we have dropped
+    // support for non-Thebes graphics, UpdateTranslucentWindowAlpha will be
+    // our private interface so we can rework things to avoid this.
+    dt->PushClipRect(Rect(boundsRect));
+
+    // The double buffering is done here to extract the shape mask.
+    // (The shape mask won't be necessary when a visual with an alpha
+    // channel is used on compositing window managers.)
+    layerBuffering = BufferMode::BUFFER_NONE;
+    RefPtr<DrawTarget> destDT =
+        dt->CreateSimilarDrawTarget(boundsRect.Size(), SurfaceFormat::B8G8R8A8);
+    if (!destDT || !destDT->IsValid()) {
+      return FALSE;
+    }
+    destDT->SetTransform(Matrix::Translation(-boundsRect.TopLeft()));
+    ctx.emplace(destDT, /* aPreserveTransform */ true);
+  } else {
+    gfxUtils::ClipToRegion(dt, region.ToUnknownRegion());
+    ctx.emplace(dt, /* aPreserveTransform */ true);
+  }
+
+#  if 0
+    // NOTE: Paint flashing region would be wrong for cairo, since
+    // cairo inflates the update region, etc.  So don't paint flash
+    // for cairo.
+#    ifdef DEBUG
+    // XXX aEvent->region may refer to a newly-invalid area.  FIXME
+    if (0 && WANT_PAINT_FLASHING && gtk_widget_get_window(aEvent))
+        gdk_window_flash(mGdkWindow, 1, 100, aEvent->region);
+#    endif
+#  endif
+
+#endif  // MOZ_X11
+
+  bool painted = false;
+  {
+    if (renderer->GetBackendType() == LayersBackend::LAYERS_NONE) {
+      if (GetTransparencyMode() == TransparencyMode::Transparent &&
+          layerBuffering == BufferMode::BUFFER_NONE && mHasAlphaVisual) {
+        // If our draw target is unbuffered and we use an alpha channel,
+        // clear the image beforehand to ensure we don't get artifacts from a
+        // reused SHM image. See bug 1258086.
+        dt->ClearRect(Rect(boundsRect));
+      }
+      AutoLayerManagerSetup setupLayerManager(
+          this, ctx.isNothing() ? nullptr : &ctx.ref(), layerBuffering);
+      painted = listener->PaintWindow(this, region);
+
+      // Re-get the listener since the will paint notification might have
+      // killed it.
+      listener = GetListener();
+      if (!listener) {
+        return TRUE;
+      }
+    }
+  }
+
+#ifdef MOZ_X11
+  // PaintWindow can Destroy us (bug 378273), avoid doing any paint
+  // operations below if that happened - it will lead to XError and exit().
+  if (shaped) {
+    if (MOZ_LIKELY(!mIsDestroyed)) {
+      if (painted) {
+        RefPtr<SourceSurface> surf = ctx->GetDrawTarget()->Snapshot();
+
+        UpdateAlpha(surf, boundsRect);
+
+        dt->DrawSurface(surf, Rect(boundsRect),
+                        Rect(0, 0, boundsRect.width, boundsRect.height),
+                        DrawSurfaceOptions(SamplingFilter::POINT),
+                        DrawOptions(1.0f, CompositionOp::OP_SOURCE));
+      }
+    }
+  }
+
+  ctx.reset();
+  dt->PopClip();
+
+#endif  // MOZ_X11
+
+  EndRemoteDrawingInRegion(dt, region);
+
+  listener->DidPaintWindow();
+
+  // Synchronously flush any new dirty areas
+  cairo_region_t* dirtyArea = gdk_window_get_update_area(mGdkWindow);
+
+  if (dirtyArea) {
+    gdk_window_invalidate_region(mGdkWindow, dirtyArea, false);
+    cairo_region_destroy(dirtyArea);
+    gdk_window_process_updates(mGdkWindow, false);
+  }
+
+  // check the return value!
+  return TRUE;
+}
+
+void nsWindow::UpdateAlpha(SourceSurface* aSourceSurface,
+                           nsIntRect aBoundsRect) {
+  // We need to create our own buffer to force the stride to match the
+  // expected stride.
+  int32_t stride =
+      GetAlignedStride<4>(aBoundsRect.width, BytesPerPixel(SurfaceFormat::A8));
+  if (stride == 0) {
+    return;
+  }
+  int32_t bufferSize = stride * aBoundsRect.height;
+  auto imageBuffer = MakeUniqueFallible<uint8_t[]>(bufferSize);
+  {
+    RefPtr<DrawTarget> drawTarget = gfxPlatform::CreateDrawTargetForData(
+        imageBuffer.get(), aBoundsRect.Size(), stride, SurfaceFormat::A8);
+
+    if (drawTarget) {
+      drawTarget->DrawSurface(aSourceSurface,
+                              Rect(0, 0, aBoundsRect.width, aBoundsRect.height),
+                              Rect(0, 0, aSourceSurface->GetSize().width,
+                                   aSourceSurface->GetSize().height),
+                              DrawSurfaceOptions(SamplingFilter::POINT),
+                              DrawOptions(1.0f, CompositionOp::OP_SOURCE));
+    }
+  }
+  UpdateTranslucentWindowAlphaInternal(aBoundsRect, imageBuffer.get(), stride);
+}
+
+gboolean nsWindow::OnConfigureEvent(GtkWidget* aWidget,
+                                    GdkEventConfigure* aEvent) {
+  // These events are only received on toplevel windows.
+  //
+  // GDK ensures that the coordinates are the client window top-left wrt the
+  // root window.
+  //
+  //   GDK calculates the cordinates for real ConfigureNotify events on
+  //   managed windows (that would normally be relative to the parent
+  //   window).
+  //
+  //   Synthetic ConfigureNotify events are from the window manager and
+  //   already relative to the root window.  GDK creates all X windows with
+  //   border_width = 0, so synthetic events also indicate the top-left of
+  //   the client window.
+  //
+  //   Override-redirect windows are children of the root window so parent
+  //   coordinates are root coordinates.
+
+#ifdef MOZ_LOGGING
+  int scale = mGdkWindow ? gdk_window_get_scale_factor(mGdkWindow) : -1;
+  LOG("configure event %d,%d -> %d x %d direct mGdkWindow scale %d (scaled "
+      "size %d x %d)\n",
+      aEvent->x, aEvent->y, aEvent->width, aEvent->height, scale,
+      aEvent->width * scale, aEvent->height * scale);
+#endif
+
+  if (mPendingConfigures > 0) {
+    mPendingConfigures--;
+  }
+
+  // Don't fire configure event for scale changes, we handle that
+  // OnScaleChanged event. Skip that for toplevel windows only.
+  if (mGdkWindow && IsTopLevelWindowType()) {
+    if (mCeiledScaleFactor != gdk_window_get_scale_factor(mGdkWindow)) {
+      LOG("  scale factor changed to %d,return early",
+          gdk_window_get_scale_factor(mGdkWindow));
+      return FALSE;
+    }
+  }
+
+  LayoutDeviceIntRect screenBounds = GetScreenBounds();
+
+  if (IsTopLevelWindowType()) {
+    // This check avoids unwanted rollup on spurious configure events from
+    // Cygwin/X (bug 672103).
+    if (mBounds.x != screenBounds.x || mBounds.y != screenBounds.y) {
+      RollupAllMenus();
+    }
+  }
+
+  NS_ASSERTION(GTK_IS_WINDOW(aWidget),
+               "Configure event on widget that is not a GtkWindow");
+  if (mGdkWindow &&
+      gtk_window_get_window_type(GTK_WINDOW(aWidget)) == GTK_WINDOW_POPUP) {
+    // Override-redirect window
+    //
+    // These windows should not be moved by the window manager, and so any
+    // change in position is a result of our direction.  mBounds has
+    // already been set in std::move() or Resize(), and that is more
+    // up-to-date than the position in the ConfigureNotify event if the
+    // event is from an earlier window move.
+    //
+    // Skipping the WindowMoved call saves context menus from an infinite
+    // loop when nsXULPopupManager::PopupMoved moves the window to the new
+    // position and nsMenuPopupFrame::SetPopupPosition adds
+    // offsetForContextMenu on each iteration.
+
+    // Our back buffer might have been invalidated while we drew the last
+    // frame, and its contents might be incorrect. See bug 1280653 comment 7
+    // and comment 10. Specifically we must ensure we recomposite the frame
+    // as soon as possible to avoid the corrupted frame being displayed.
+    GetWindowRenderer()->FlushRendering(wr::RenderReasons::WIDGET);
+    return FALSE;
+  }
+
+  mBounds.MoveTo(screenBounds.TopLeft());
+  RecomputeClientOffset(/* aNotify = */ false);
+
+  // XXX mozilla will invalidate the entire window after this move
+  // complete.  wtf?
+  NotifyWindowMoved(mBounds.x, mBounds.y);
+
+  return FALSE;
+}
+
+void nsWindow::OnMap() {
+  LOG("nsWindow::OnMap");
+  // Gtk mapped widget to screen. Configure underlying GdkWindow properly
+  // as our rendering target.
+  // This call means we have X11 (or Wayland) window we can render to by GL
+  // so we need to notify compositor about it.
+  mIsMapped = true;
+  ConfigureGdkWindow();
+}
+
+void nsWindow::OnUnmap() {
+  LOG("nsWindow::OnUnmap");
+
+  mIsMapped = false;
+
+  if (mSourceDragContext) {
+    static auto sGtkDragCancel =
+        (void (*)(GdkDragContext*))dlsym(RTLD_DEFAULT, "gtk_drag_cancel");
+    if (sGtkDragCancel) {
+      sGtkDragCancel(mSourceDragContext);
+      mSourceDragContext = nullptr;
+    }
+  }
+}
+
+void nsWindow::OnSizeAllocate(GtkAllocation* aAllocation) {
+  LOG("nsWindow::OnSizeAllocate %d,%d -> %d x %d\n", aAllocation->x,
+      aAllocation->y, aAllocation->width, aAllocation->height);
+
+  // Client offset are updated by _NET_FRAME_EXTENTS on X11 when system titlebar
+  // is enabled. In either cases (Wayland or system titlebar is off on X11)
+  // we don't get _NET_FRAME_EXTENTS X11 property notification so we derive
+  // it from mContainer position.
+  RecomputeClientOffset(/* aNotify = */ true);
+
+  mHasReceivedSizeAllocate = true;
+
+  LayoutDeviceIntSize size = GdkRectToDevicePixels(*aAllocation).Size();
+
+  // Sometimes the window manager gives us garbage sizes (way past the maximum
+  // texture size) causing crashes if we don't enforce size constraints again
+  // here.
+  ConstrainSize(&size.width, &size.height);
+
+  if (mBounds.Size() == size) {
+    LOG("  Already the same size");
+    // mBounds was set at Create() or Resize().
+    if (mNeedsDispatchSize != LayoutDeviceIntSize(-1, -1)) {
+      LOG("  No longer needs to dispatch %dx%d", mNeedsDispatchSize.width,
+          mNeedsDispatchSize.height);
+      mNeedsDispatchSize = LayoutDeviceIntSize(-1, -1);
+    }
+    return;
+  }
+
+  // Invalidate the new part of the window now for the pending paint to
+  // minimize background flashes (GDK does not do this for external resizes
+  // of toplevels.)
+  if (mGdkWindow) {
+    if (mBounds.width < size.width) {
+      GdkRectangle rect = DevicePixelsToGdkRectRoundOut(LayoutDeviceIntRect(
+          mBounds.width, 0, size.width - mBounds.width, size.height));
+      gdk_window_invalidate_rect(mGdkWindow, &rect, FALSE);
+    }
+    if (mBounds.height < size.height) {
+      GdkRectangle rect = DevicePixelsToGdkRectRoundOut(LayoutDeviceIntRect(
+          0, mBounds.height, size.width, size.height - mBounds.height));
+      gdk_window_invalidate_rect(mGdkWindow, &rect, FALSE);
+    }
+  }
+
+  // If we update mBounds here, then inner/outerHeight are out of sync until
+  // we call WindowResized.
+  mNeedsDispatchSize = size;
+
+  // Gecko permits running nested event loops during processing of events,
+  // GtkWindow callers of gtk_widget_size_allocate expect the signal
+  // handlers to return sometime in the near future.
+  NS_DispatchToCurrentThread(NewRunnableMethod(
+      "nsWindow::MaybeDispatchResized", this, &nsWindow::MaybeDispatchResized));
+}
+
+void nsWindow::OnDeleteEvent() {
+  if (mWidgetListener) mWidgetListener->RequestWindowClose(this);
+}
+
+void nsWindow::OnEnterNotifyEvent(GdkEventCrossing* aEvent) {
+  LOG("enter notify (win=%p, sub=%p): %f, %f mode %d, detail %d\n",
+      aEvent->window, aEvent->subwindow, aEvent->x, aEvent->y, aEvent->mode,
+      aEvent->detail);
+  // This skips NotifyVirtual and NotifyNonlinearVirtual enter notify events
+  // when the pointer enters a child window.  If the destination window is a
+  // Gecko window then we'll catch the corresponding event on that window,
+  // but we won't notice when the pointer directly enters a foreign (plugin)
+  // child window without passing over a visible portion of a Gecko window.
+  if (aEvent->subwindow) {
+    return;
+  }
+
+  // Check before checking for ungrab as the button state may have
+  // changed while a non-Gecko ancestor window had a pointer grab.
+  DispatchMissedButtonReleases(aEvent);
+
+  WidgetMouseEvent event(true, eMouseEnterIntoWidget, this,
+                         WidgetMouseEvent::eReal);
+
+  event.mRefPoint = GdkEventCoordsToDevicePixels(aEvent->x, aEvent->y);
+  event.AssignEventTime(GetWidgetEventTime(aEvent->time));
+
+  LOG("OnEnterNotify");
+
+  DispatchInputEvent(&event);
+}
+
+// Some window managers send a bogus top-level leave-notify event on every
+// click. That confuses our event handling code in ways that can break websites,
+// see bug 1805939 for details.
+//
+// Make sure to only check this on bogus environments, since for environments
+// with CSD, gdk_device_get_window_at_position could return the window even when
+// the pointer is in the decoration area.
+static bool IsBogusLeaveNotifyEvent(GdkWindow* aWindow,
+                                    GdkEventCrossing* aEvent) {
+  static bool sBogusWm = [] {
+    if (GdkIsWaylandDisplay()) {
+      return false;
+    }
+    const auto& desktopEnv = GetDesktopEnvironmentIdentifier();
+    return desktopEnv.EqualsLiteral("fluxbox") ||   // Bug 1805939 comment 0.
+           desktopEnv.EqualsLiteral("blackbox") ||  // Bug 1805939 comment 32.
+           desktopEnv.EqualsLiteral("lg3d") ||      // Bug 1820405.
+           desktopEnv.EqualsLiteral("pekwm") ||     // Bug 1822911.
+           StringBeginsWith(desktopEnv, "fvwm"_ns);
+  }();
+
+  const bool shouldCheck = [] {
+    switch (StaticPrefs::widget_gtk_ignore_bogus_leave_notify()) {
+      case 0:
+        return false;
+      case 1:
+        return true;
+      default:
+        return sBogusWm;
+    }
+  }();
+
+  if (!shouldCheck || !aWindow) {
+    return false;
+  }
+  GdkDevice* pointer = GdkGetPointer();
+  GdkWindow* winAtPt =
+      gdk_device_get_window_at_position(pointer, nullptr, nullptr);
+  if (!winAtPt) {
+    return false;
+  }
+  // We're still in the same top level window, ignore this leave notify event.
+  GdkWindow* topLevelAtPt = gdk_window_get_toplevel(winAtPt);
+  GdkWindow* topLevelWidget = gdk_window_get_toplevel(aWindow);
+  return topLevelAtPt == topLevelWidget;
+}
+
+void nsWindow::OnLeaveNotifyEvent(GdkEventCrossing* aEvent) {
+  LOG("leave notify (win=%p, sub=%p): %f, %f mode %d, detail %d\n",
+      aEvent->window, aEvent->subwindow, aEvent->x, aEvent->y, aEvent->mode,
+      aEvent->detail);
+
+  // This ignores NotifyVirtual and NotifyNonlinearVirtual leave notify
+  // events when the pointer leaves a child window.  If the destination
+  // window is a Gecko window then we'll catch the corresponding event on
+  // that window.
+  //
+  // XXXkt However, we will miss toplevel exits when the pointer directly
+  // leaves a foreign (plugin) child window without passing over a visible
+  // portion of a Gecko window.
+  if (aEvent->subwindow) {
+    return;
+  }
+
+  // The filter out for subwindows should make sure that this is targeted to
+  // this nsWindow.
+  const bool leavingTopLevel = IsTopLevelWindowType();
+  if (leavingTopLevel && IsBogusLeaveNotifyEvent(mGdkWindow, aEvent)) {
+    return;
+  }
+
+  WidgetMouseEvent event(true, eMouseExitFromWidget, this,
+                         WidgetMouseEvent::eReal);
+
+  event.mRefPoint = GdkEventCoordsToDevicePixels(aEvent->x, aEvent->y);
+  event.AssignEventTime(GetWidgetEventTime(aEvent->time));
+  event.mExitFrom = Some(leavingTopLevel ? WidgetMouseEvent::ePlatformTopLevel
+                                         : WidgetMouseEvent::ePlatformChild);
+
+  LOG("OnLeaveNotify");
+
+  DispatchInputEvent(&event);
+}
+
+Maybe<GdkWindowEdge> nsWindow::CheckResizerEdge(
+    const LayoutDeviceIntPoint& aPoint) {
+  const bool canResize = [&] {
+    // Don't allow resizing maximized/fullscreen windows.
+    if (mSizeMode != nsSizeMode_Normal) {
+      return false;
+    }
+    if (mIsPIPWindow) {
+      // Note that since we do show resizers on left/right sides on PIP windows,
+      // we still want the resizers there, even when tiled.
+      return true;
+    }
+    if (!mDrawInTitlebar) {
+      return false;
+    }
+    // On KDE, allow for 1 extra pixel at the top of regular windows when
+    // drawing to the titlebar. This matches the native titlebar behavior on
+    // that environment. See bug 1813554.
+    //
+    // Don't do that on GNOME (see bug 1822764). If we wanted to do this on
+    // GNOME we'd need an extra check for mIsTiled, since the window is "stuck"
+    // to the top and bottom.
+    //
+    // Other DEs are untested.
+    return mDrawInTitlebar && IsKdeDesktopEnvironment();
+  }();
+
+  if (!canResize) {
+    return Nothing();
+  }
+
+  // If we're not in a PiP window, allow 1px resizer edge from the top edge,
+  // and nothing else.
+  // This is to allow resizes of tiled windows on KDE, see bug 1813554.
+  const int resizerHeight = (mIsPIPWindow ? 15 : 1) * GdkCeiledScaleFactor();
+  const int resizerWidth = resizerHeight * 4;
+
+  const int topDist = aPoint.y;
+  const int leftDist = aPoint.x;
+  const int rightDist = mBounds.width - aPoint.x;
+  const int bottomDist = mBounds.height - aPoint.y;
+
+  // We can't emulate resize of North/West edges on Wayland as we can't shift
+  // toplevel window.
+  bool waylandLimitedResize = mAspectRatio != 0.0f && GdkIsWaylandDisplay();
+
+  if (topDist <= resizerHeight) {
+    if (rightDist <= resizerWidth) {
+      return Some(GDK_WINDOW_EDGE_NORTH_EAST);
+    }
+    if (leftDist <= resizerWidth) {
+      return Some(GDK_WINDOW_EDGE_NORTH_WEST);
+    }
+    return waylandLimitedResize ? Nothing() : Some(GDK_WINDOW_EDGE_NORTH);
+  }
+
+  if (!mIsPIPWindow) {
+    return Nothing();
+  }
+
+  if (bottomDist <= resizerHeight) {
+    if (leftDist <= resizerWidth) {
+      return Some(GDK_WINDOW_EDGE_SOUTH_WEST);
+    }
+    if (rightDist <= resizerWidth) {
+      return Some(GDK_WINDOW_EDGE_SOUTH_EAST);
+    }
+    return Some(GDK_WINDOW_EDGE_SOUTH);
+  }
+
+  if (leftDist <= resizerHeight) {
+    if (topDist <= resizerWidth) {
+      return Some(GDK_WINDOW_EDGE_NORTH_WEST);
+    }
+    if (bottomDist <= resizerWidth) {
+      return Some(GDK_WINDOW_EDGE_SOUTH_WEST);
+    }
+    return waylandLimitedResize ? Nothing() : Some(GDK_WINDOW_EDGE_WEST);
+  }
+
+  if (rightDist <= resizerHeight) {
+    if (topDist <= resizerWidth) {
+      return Some(GDK_WINDOW_EDGE_NORTH_EAST);
+    }
+    if (bottomDist <= resizerWidth) {
+      return Some(GDK_WINDOW_EDGE_SOUTH_EAST);
+    }
+    return Some(GDK_WINDOW_EDGE_EAST);
+  }
+  return Nothing();
+}
+
+template <typename Event>
+static LayoutDeviceIntPoint GetRefPoint(nsWindow* aWindow, Event* aEvent) {
+  if (aEvent->window == aWindow->GetGdkWindow()) {
+    // we are the window that the event happened on so no need for expensive
+    // WidgetToScreenOffset
+    return aWindow->GdkEventCoordsToDevicePixels(aEvent->x, aEvent->y);
+  }
+  // XXX we're never quite sure which GdkWindow the event came from due to our
+  // custom bubbling in scroll_event_cb(), so use ScreenToWidget to translate
+  // the screen root coordinates into coordinates relative to this widget.
+  return aWindow->GdkEventCoordsToDevicePixels(aEvent->x_root, aEvent->y_root) -
+         aWindow->WidgetToScreenOffset();
+}
+
+void nsWindow::EmulateResizeDrag(GdkEventMotion* aEvent) {
+  auto newPoint = LayoutDeviceIntPoint::Floor(aEvent->x, aEvent->y);
+  LayoutDeviceIntPoint diff = newPoint - mLastResizePoint;
+  mLastResizePoint = newPoint;
+
+  GdkRectangle size = DevicePixelsToGdkSizeRoundUp(mBounds.Size());
+  LayoutDeviceIntSize newSize(size.width + diff.x, size.height + diff.y);
+
+  if (mAspectResizer.value() == GTK_ORIENTATION_VERTICAL) {
+    newSize.width = int(newSize.height * mAspectRatio);
+  } else {  // GTK_ORIENTATION_HORIZONTAL
+    newSize.height = int(newSize.width / mAspectRatio);
+  }
+  LOG("  aspect ratio correction %d x %d aspect %f\n", newSize.width,
+      newSize.height, mAspectRatio);
+  gtk_window_resize(GTK_WINDOW(mShell), newSize.width, newSize.height);
+}
+
+void nsWindow::OnMotionNotifyEvent(GdkEventMotion* aEvent) {
+  if (!mGdkWindow) {
+    return;
+  }
+
+  // Emulate gdk_window_begin_resize_drag() for windows
+  // with fixed aspect ratio on Wayland.
+  if (mAspectResizer && mAspectRatio != 0.0f) {
+    EmulateResizeDrag(aEvent);
+    return;
+  }
+
+  if (mWindowShouldStartDragging) {
+    mWindowShouldStartDragging = false;
+    GdkWindow* dragWindow = nullptr;
+
+    // find the top-level window
+    if (mGdkWindow) {
+      dragWindow = gdk_window_get_toplevel(mGdkWindow);
+      MOZ_ASSERT(dragWindow, "gdk_window_get_toplevel should not return null");
+    }
+
+#ifdef MOZ_X11
+    if (dragWindow && GdkIsX11Display()) {
+      // Workaround for https://bugzilla.gnome.org/show_bug.cgi?id=789054
+      // To avoid crashes disable double-click on WM without _NET_WM_MOVERESIZE.
+      // See _should_perform_ewmh_drag() at gdkwindow-x11.c
+      GdkScreen* screen = gdk_window_get_screen(dragWindow);
+      GdkAtom atom = gdk_atom_intern("_NET_WM_MOVERESIZE", FALSE);
+      if (!gdk_x11_screen_supports_net_wm_hint(screen, atom)) {
+        dragWindow = nullptr;
+      }
+    }
+#endif
+
+    if (dragWindow) {
+      gdk_window_begin_move_drag(dragWindow, 1, aEvent->x_root, aEvent->y_root,
+                                 aEvent->time);
+      return;
+    }
+  }
+
+  mWidgetCursorLocked = false;
+  const auto refPoint = GetRefPoint(this, aEvent);
+  if (auto edge = CheckResizerEdge(refPoint)) {
+    nsCursor cursor = eCursor_none;
+    switch (*edge) {
+      case GDK_WINDOW_EDGE_SOUTH:
+      case GDK_WINDOW_EDGE_NORTH:
+        cursor = eCursor_ns_resize;
+        break;
+      case GDK_WINDOW_EDGE_WEST:
+      case GDK_WINDOW_EDGE_EAST:
+        cursor = eCursor_ew_resize;
+        break;
+      case GDK_WINDOW_EDGE_NORTH_WEST:
+      case GDK_WINDOW_EDGE_SOUTH_EAST:
+        cursor = eCursor_nwse_resize;
+        break;
+      case GDK_WINDOW_EDGE_NORTH_EAST:
+      case GDK_WINDOW_EDGE_SOUTH_WEST:
+        cursor = eCursor_nesw_resize;
+        break;
+    }
+    SetCursor(Cursor{cursor});
+    // If we set resize cursor on widget level keep it locked and prevent layout
+    // to switch it back to default (by synthetic mouse events for instance)
+    // until resize is finished. This affects PIP windows only.
+    if (mIsPIPWindow) {
+      mWidgetCursorLocked = true;
+    }
+    return;
+  }
+
+  WidgetMouseEvent event(true, eMouseMove, this, WidgetMouseEvent::eReal);
+
+  gdouble pressure = 0;
+  gdk_event_get_axis((GdkEvent*)aEvent, GDK_AXIS_PRESSURE, &pressure);
+  // Sometime gdk generate 0 pressure value between normal values
+  // We have to ignore that and use last valid value
+  if (pressure) {
+    mLastMotionPressure = pressure;
+  }
+  event.mPressure = mLastMotionPressure;
+  event.mRefPoint = refPoint;
+  event.AssignEventTime(GetWidgetEventTime(aEvent->time));
+
+  KeymapWrapper::InitInputEvent(event, aEvent->state);
+
+  DispatchInputEvent(&event);
+}
+
+// If the automatic pointer grab on ButtonPress has deactivated before
+// ButtonRelease, and the mouse button is released while the pointer is not
+// over any a Gecko window, then the ButtonRelease event will not be received.
+// (A similar situation exists when the pointer is grabbed with owner_events
+// True as the ButtonRelease may be received on a foreign [plugin] window).
+// Use this method to check for released buttons when the pointer returns to a
+// Gecko window.
+void nsWindow::DispatchMissedButtonReleases(GdkEventCrossing* aGdkEvent) {
+  guint changed = aGdkEvent->state ^ gButtonState;
+  // Only consider button releases.
+  // (Ignore button presses that occurred outside Gecko.)
+  guint released = changed & gButtonState;
+  gButtonState = aGdkEvent->state;
+
+  // Loop over each button, excluding mouse wheel buttons 4 and 5 for which
+  // GDK ignores releases.
+  for (guint buttonMask = GDK_BUTTON1_MASK; buttonMask <= GDK_BUTTON3_MASK;
+       buttonMask <<= 1) {
+    if (released & buttonMask) {
+      int16_t buttonType;
+      switch (buttonMask) {
+        case GDK_BUTTON1_MASK:
+          buttonType = MouseButton::ePrimary;
+          break;
+        case GDK_BUTTON2_MASK:
+          buttonType = MouseButton::eMiddle;
+          break;
+        default:
+          NS_ASSERTION(buttonMask == GDK_BUTTON3_MASK,
+                       "Unexpected button mask");
+          buttonType = MouseButton::eSecondary;
+      }
+
+      LOG("Synthesized button %u release", guint(buttonType + 1));
+
+      // Dispatch a synthesized button up event to tell Gecko about the
+      // change in state.  This event is marked as synthesized so that
+      // it is not dispatched as a DOM event, because we don't know the
+      // position, widget, modifiers, or time/order.
+      WidgetMouseEvent synthEvent(true, eMouseUp, this,
+                                  WidgetMouseEvent::eSynthesized);
+      synthEvent.mButton = buttonType;
+      DispatchInputEvent(&synthEvent);
+    }
+  }
+}
+
+void nsWindow::InitButtonEvent(WidgetMouseEvent& aEvent,
+                               GdkEventButton* aGdkEvent,
+                               const LayoutDeviceIntPoint& aRefPoint) {
+  aEvent.mRefPoint = aRefPoint;
+
+  guint modifierState = aGdkEvent->state;
+  // aEvent's state includes the button state from immediately before this
+  // event.  If aEvent is a mousedown or mouseup event, we need to update
+  // the button state.
+  guint buttonMask = 0;
+  switch (aGdkEvent->button) {
+    case 1:
+      buttonMask = GDK_BUTTON1_MASK;
+      break;
+    case 2:
+      buttonMask = GDK_BUTTON2_MASK;
+      break;
+    case 3:
+      buttonMask = GDK_BUTTON3_MASK;
+      break;
+  }
+  if (aGdkEvent->type == GDK_BUTTON_RELEASE) {
+    modifierState &= ~buttonMask;
+  } else {
+    modifierState |= buttonMask;
+  }
+
+  KeymapWrapper::InitInputEvent(aEvent, modifierState);
+
+  aEvent.AssignEventTime(GetWidgetEventTime(aGdkEvent->time));
+
+  switch (aGdkEvent->type) {
+    case GDK_2BUTTON_PRESS:
+      aEvent.mClickCount = 2;
+      break;
+    case GDK_3BUTTON_PRESS:
+      aEvent.mClickCount = 3;
+      break;
+      // default is one click
+    default:
+      aEvent.mClickCount = 1;
+  }
+}
+
+static guint ButtonMaskFromGDKButton(guint button) {
+  return GDK_BUTTON1_MASK << (button - 1);
+}
+
+void nsWindow::DispatchContextMenuEventFromMouseEvent(
+    uint16_t domButton, GdkEventButton* aEvent,
+    const LayoutDeviceIntPoint& aRefPoint) {
+  if (domButton == MouseButton::eSecondary && MOZ_LIKELY(!mIsDestroyed)) {
+    WidgetMouseEvent contextMenuEvent(true, eContextMenu, this,
+                                      WidgetMouseEvent::eReal);
+    InitButtonEvent(contextMenuEvent, aEvent, aRefPoint);
+    contextMenuEvent.mPressure = mLastMotionPressure;
+    DispatchInputEvent(&contextMenuEvent);
+  }
+}
+
+void nsWindow::TryToShowNativeWindowMenu(GdkEventButton* aEvent) {
+  if (!gdk_window_show_window_menu(GetToplevelGdkWindow(), (GdkEvent*)aEvent)) {
+    NS_WARNING("Native context menu wasn't shown");
+  }
+}
+
+bool nsWindow::DoTitlebarAction(LookAndFeel::TitlebarEvent aEvent,
+                                GdkEventButton* aButtonEvent) {
+  LOG("DoTitlebarAction %s click",
+      aEvent == LookAndFeel::TitlebarEvent::Double_Click ? "double" : "middle");
+  switch (LookAndFeel::GetTitlebarAction(aEvent)) {
+    case LookAndFeel::TitlebarAction::WindowMenu:
+      // Titlebar app menu
+      LOG("  action menu");
+      TryToShowNativeWindowMenu(aButtonEvent);
+      break;
+    // Lower is part of gtk_surface1 protocol which we can't support
+    // as Gtk keeps it private. So emulate it by minimize.
+    case LookAndFeel::TitlebarAction::WindowLower:
+    case LookAndFeel::TitlebarAction::WindowMinimize:
+      LOG("  action minimize");
+      SetSizeMode(nsSizeMode_Minimized);
+      break;
+    case LookAndFeel::TitlebarAction::WindowMaximize:
+      LOG("  action maximize");
+      SetSizeMode(nsSizeMode_Maximized);
+      break;
+    case LookAndFeel::TitlebarAction::WindowMaximizeToggle:
+      LOG("  action toggle maximize");
+      if (mSizeMode == nsSizeMode_Maximized) {
+        SetSizeMode(nsSizeMode_Normal);
+      } else if (mSizeMode == nsSizeMode_Normal) {
+        SetSizeMode(nsSizeMode_Maximized);
+      }
+      break;
+    case LookAndFeel::TitlebarAction::None:
+    default:
+      LOG("  action none");
+      return false;
+  }
+  return true;
+}
+
+void nsWindow::OnButtonPressEvent(GdkEventButton* aEvent) {
+  LOG("Button %u press\n", aEvent->button);
+
+  SetLastMousePressEvent((GdkEvent*)aEvent);
+
+  // If you double click in GDK, it will actually generate a second
+  // GDK_BUTTON_PRESS before sending the GDK_2BUTTON_PRESS, and this is
+  // different than the DOM spec.  GDK puts this in the queue
+  // programatically, so it's safe to assume that if there's a
+  // double click in the queue, it was generated so we can just drop
+  // this click.
+  GUniquePtr<GdkEvent> peekedEvent(gdk_event_peek());
+  if (peekedEvent) {
+    GdkEventType type = peekedEvent->any.type;
+    if (type == GDK_2BUTTON_PRESS || type == GDK_3BUTTON_PRESS) {
+      return;
+    }
+  }
+
+  nsWindow* containerWindow = GetContainerWindow();
+  if (!gFocusWindow && containerWindow) {
+    containerWindow->DispatchActivateEvent();
+  }
+
+  const auto refPoint = GetRefPoint(this, aEvent);
+
+  // check to see if we should rollup
+  if (CheckForRollup(aEvent->x_root, aEvent->y_root, false, false)) {
+    if (aEvent->button == 3 && mDraggableRegion.Contains(refPoint)) {
+      GUniquePtr<GdkEvent> eventCopy;
+      if (aEvent->type != GDK_BUTTON_PRESS) {
+        // If the user double-clicks too fast we'll get a 2BUTTON_PRESS event
+        // instead, and that isn't handled by open_window_menu, so coerce it
+        // into a regular press.
+        eventCopy.reset(gdk_event_copy((GdkEvent*)aEvent));
+        eventCopy->type = GDK_BUTTON_PRESS;
+      }
+      TryToShowNativeWindowMenu(eventCopy ? &eventCopy->button : aEvent);
+    }
+    return;
+  }
+
+  // Check to see if the event is within our window's resize region
+  if (auto edge = CheckResizerEdge(refPoint)) {
+    // On Wayland Gtk fails to vertically/horizontally resize windows
+    // with fixed aspect ratio. We need to emulate
+    // gdk_window_begin_resize_drag() at OnMotionNotifyEvent().
+    if (mAspectRatio != 0.0f && GdkIsWaylandDisplay()) {
+      mLastResizePoint = LayoutDeviceIntPoint::Floor(aEvent->x, aEvent->y);
+      switch (*edge) {
+        case GDK_WINDOW_EDGE_SOUTH:
+          mAspectResizer = Some(GTK_ORIENTATION_VERTICAL);
+          break;
+        case GDK_WINDOW_EDGE_EAST:
+          mAspectResizer = Some(GTK_ORIENTATION_HORIZONTAL);
+          break;
+        default:
+          mAspectResizer.reset();
+          break;
+      }
+      ApplySizeConstraints();
+    }
+    if (!mAspectResizer) {
+      gdk_window_begin_resize_drag(GetToplevelGdkWindow(), *edge,
+                                   aEvent->button, aEvent->x_root,
+                                   aEvent->y_root, aEvent->time);
+    }
+    return;
+  }
+
+  gdouble pressure = 0;
+  gdk_event_get_axis((GdkEvent*)aEvent, GDK_AXIS_PRESSURE, &pressure);
+  mLastMotionPressure = pressure;
+
+  uint16_t domButton;
+  switch (aEvent->button) {
+    case 1:
+      domButton = MouseButton::ePrimary;
+      break;
+    case 2:
+      domButton = MouseButton::eMiddle;
+      break;
+    case 3:
+      domButton = MouseButton::eSecondary;
+      break;
+    // These are mapped to horizontal scroll
+    case 6:
+    case 7:
+      NS_WARNING("We're not supporting legacy horizontal scroll event");
+      return;
+    // Map buttons 8-9(10) to back/forward
+    case 8:
+      if (!Preferences::GetBool("mousebutton.4th.enabled", true)) {
+        return;
+      }
+      DispatchCommandEvent(nsGkAtoms::Back);
+      return;
+    case 9:
+    case 10:
+      if (!Preferences::GetBool("mousebutton.5th.enabled", true)) {
+        return;
+      }
+      DispatchCommandEvent(nsGkAtoms::Forward);
+      return;
+    default:
+      return;
+  }
+
+  gButtonState |= ButtonMaskFromGDKButton(aEvent->button);
+
+  WidgetMouseEvent event(true, eMouseDown, this, WidgetMouseEvent::eReal);
+  event.mButton = domButton;
+  InitButtonEvent(event, aEvent, refPoint);
+  event.mPressure = mLastMotionPressure;
+
+  nsIWidget::ContentAndAPZEventStatus eventStatus = DispatchInputEvent(&event);
+
+  const bool defaultPrevented =
+      eventStatus.mContentStatus == nsEventStatus_eConsumeNoDefault;
+
+  if (!defaultPrevented && mDraggableRegion.Contains(refPoint)) {
+    if (domButton == MouseButton::ePrimary) {
+      mWindowShouldStartDragging = true;
+    } else if (domButton == MouseButton::eMiddle &&
+               StaticPrefs::widget_gtk_titlebar_action_middle_click_enabled()) {
+      DoTitlebarAction(nsXPLookAndFeel::TitlebarEvent::Middle_Click, aEvent);
+    }
+  }
+
+  // right menu click on linux should also pop up a context menu
+  if (!StaticPrefs::ui_context_menus_after_mouseup() &&
+      eventStatus.mApzStatus != nsEventStatus_eConsumeNoDefault) {
+    DispatchContextMenuEventFromMouseEvent(domButton, aEvent, refPoint);
+  }
+}
+
+void nsWindow::OnButtonReleaseEvent(GdkEventButton* aEvent) {
+  LOG("Button %u release\n", aEvent->button);
+
+  SetLastMousePressEvent(nullptr);
+
+  if (!mGdkWindow) {
+    return;
+  }
+
+  if (mAspectResizer) {
+    mAspectResizer = Nothing();
+    return;
+  }
+
+  if (mWindowShouldStartDragging) {
+    mWindowShouldStartDragging = false;
+  }
+
+  uint16_t domButton;
+  switch (aEvent->button) {
+    case 1:
+      domButton = MouseButton::ePrimary;
+      break;
+    case 2:
+      domButton = MouseButton::eMiddle;
+      break;
+    case 3:
+      domButton = MouseButton::eSecondary;
+      break;
+    default:
+      return;
+  }
+
+  gButtonState &= ~ButtonMaskFromGDKButton(aEvent->button);
+
+  const auto refPoint = GetRefPoint(this, aEvent);
+
+  WidgetMouseEvent event(true, eMouseUp, this, WidgetMouseEvent::eReal);
+  event.mButton = domButton;
+  InitButtonEvent(event, aEvent, refPoint);
+  gdouble pressure = 0;
+  gdk_event_get_axis((GdkEvent*)aEvent, GDK_AXIS_PRESSURE, &pressure);
+  event.mPressure = pressure ? (float)pressure : (float)mLastMotionPressure;
+
+  // The mRefPoint is manipulated in DispatchInputEvent, we're saving it
+  // to use it for the doubleclick position check.
+  const LayoutDeviceIntPoint pos = event.mRefPoint;
+
+  nsIWidget::ContentAndAPZEventStatus eventStatus = DispatchInputEvent(&event);
+
+  const bool defaultPrevented =
+      eventStatus.mContentStatus == nsEventStatus_eConsumeNoDefault;
+  // Check if mouse position in titlebar and doubleclick happened to
+  // trigger defined action.
+  if (!defaultPrevented && mDrawInTitlebar &&
+      event.mButton == MouseButton::ePrimary && event.mClickCount == 2 &&
+      mDraggableRegion.Contains(pos)) {
+    DoTitlebarAction(nsXPLookAndFeel::TitlebarEvent::Double_Click, aEvent);
+  }
+  mLastMotionPressure = pressure;
+
+  // right menu click on linux should also pop up a context menu
+  if (StaticPrefs::ui_context_menus_after_mouseup() &&
+      eventStatus.mApzStatus != nsEventStatus_eConsumeNoDefault) {
+    DispatchContextMenuEventFromMouseEvent(domButton, aEvent, refPoint);
+  }
+
+  // Open window manager menu on PIP window to allow user
+  // to place it on top / all workspaces.
+  if (mAlwaysOnTop && aEvent->button == 3) {
+    TryToShowNativeWindowMenu(aEvent);
+  }
+}
+
+void nsWindow::OnContainerFocusInEvent(GdkEventFocus* aEvent) {
+  LOG("OnContainerFocusInEvent");
+
+  // Unset the urgency hint, if possible
+  GtkWidget* top_window = GetToplevelWidget();
+  if (top_window && (gtk_widget_get_visible(top_window))) {
+    SetUrgencyHint(top_window, false);
+  }
+
+  // Return if being called within SetFocus because the focus manager
+  // already knows that the window is active.
+  if (gBlockActivateEvent) {
+    LOG("activated notification is blocked");
+    return;
+  }
+
+  // If keyboard input will be accepted, the focus manager will call
+  // SetFocus to set the correct window.
+  gFocusWindow = nullptr;
+
+  DispatchActivateEvent();
+
+  if (!gFocusWindow) {
+    // We don't really have a window for dispatching key events, but
+    // setting a non-nullptr value here prevents OnButtonPressEvent() from
+    // dispatching an activation notification if the widget is already
+    // active.
+    gFocusWindow = this;
+  }
+
+  LOG("Events sent from focus in event");
+}
+
+void nsWindow::OnContainerFocusOutEvent(GdkEventFocus* aEvent) {
+  LOG("OnContainerFocusOutEvent");
+
+  if (IsTopLevelWindowType()) {
+    // Rollup menus when a window is focused out unless a drag is occurring.
+    // This check is because drags grab the keyboard and cause a focus out on
+    // versions of GTK before 2.18.
+    const bool shouldRollupMenus = [&] {
+      nsCOMPtr<nsIDragService> dragService =
+          do_GetService("@mozilla.org/widget/dragservice;1");
+      nsCOMPtr<nsIDragSession> dragSession;
+      dragService->GetCurrentSession(getter_AddRefs(dragSession));
+      if (!dragSession) {
+        return true;
+      }
+      // We also roll up when a drag is from a different application
+      nsCOMPtr<nsINode> sourceNode;
+      dragSession->GetSourceNode(getter_AddRefs(sourceNode));
+      return !sourceNode;
+    }();
+
+    if (shouldRollupMenus) {
+      RollupAllMenus();
+    }
+
+    if (RefPtr pm = nsXULPopupManager::GetInstance()) {
+      pm->RollupTooltips();
+    }
+  }
+
+  if (gFocusWindow) {
+    RefPtr<nsWindow> kungFuDeathGrip = gFocusWindow;
+    if (gFocusWindow->mIMContext) {
+      gFocusWindow->mIMContext->OnBlurWindow(gFocusWindow);
+    }
+    gFocusWindow = nullptr;
+  }
+
+  DispatchDeactivateEvent();
+
+  if (IsChromeWindowTitlebar()) {
+    // DispatchDeactivateEvent() ultimately results in a call to
+    // BrowsingContext::SetIsActiveBrowserWindow(), which resets
+    // the state.  We call UpdateMozWindowActive() to keep it in
+    // sync with GDK_WINDOW_STATE_FOCUSED.
+    UpdateMozWindowActive();
+  }
+
+  LOG("Done with container focus out");
+}
+
+bool nsWindow::DispatchCommandEvent(nsAtom* aCommand) {
+  nsEventStatus status;
+  WidgetCommandEvent appCommandEvent(true, aCommand, this);
+  DispatchEvent(&appCommandEvent, status);
+  return TRUE;
+}
+
+bool nsWindow::DispatchContentCommandEvent(EventMessage aMsg) {
+  nsEventStatus status;
+  WidgetContentCommandEvent event(true, aMsg, this);
+  DispatchEvent(&event, status);
+  return TRUE;
+}
+
+WidgetEventTime nsWindow::GetWidgetEventTime(guint32 aEventTime) {
+  return WidgetEventTime(GetEventTimeStamp(aEventTime));
+}
+
+TimeStamp nsWindow::GetEventTimeStamp(guint32 aEventTime) {
+  if (MOZ_UNLIKELY(!mGdkWindow)) {
+    // nsWindow has been Destroy()ed.
+    return TimeStamp::Now();
+  }
+  if (aEventTime == 0) {
+    // Some X11 and GDK events may be received with a time of 0 to indicate
+    // that they are synthetic events. Some input method editors do this.
+    // In this case too, just return the current timestamp.
+    return TimeStamp::Now();
+  }
+
+  TimeStamp eventTimeStamp;
+
+  if (GdkIsWaylandDisplay()) {
+    // Wayland compositors use monotonic time to set timestamps.
+    int64_t timestampTime = g_get_monotonic_time() / 1000;
+    guint32 refTimeTruncated = guint32(timestampTime);
+
+    timestampTime -= refTimeTruncated - aEventTime;
+    int64_t tick =
+        BaseTimeDurationPlatformUtils::TicksFromMilliseconds(timestampTime);
+    eventTimeStamp = TimeStamp::FromSystemTime(tick);
+  } else {
+#ifdef MOZ_X11
+    CurrentX11TimeGetter* getCurrentTime = GetCurrentTimeGetter();
+    MOZ_ASSERT(getCurrentTime,
+               "Null current time getter despite having a window");
+    eventTimeStamp =
+        TimeConverter().GetTimeStampFromSystemTime(aEventTime, *getCurrentTime);
+#endif
+  }
+  return eventTimeStamp;
+}
+
+#ifdef MOZ_X11
+mozilla::CurrentX11TimeGetter* nsWindow::GetCurrentTimeGetter() {
+  MOZ_ASSERT(mGdkWindow, "Expected mGdkWindow to be set");
+  if (MOZ_UNLIKELY(!mCurrentTimeGetter)) {
+    mCurrentTimeGetter = MakeUnique<CurrentX11TimeGetter>(mGdkWindow);
+  }
+  return mCurrentTimeGetter.get();
+}
+#endif
+
+gboolean nsWindow::OnKeyPressEvent(GdkEventKey* aEvent) {
+  LOG("OnKeyPressEvent");
+
+  KeymapWrapper::HandleKeyPressEvent(this, aEvent);
+  return TRUE;
+}
+
+gboolean nsWindow::OnKeyReleaseEvent(GdkEventKey* aEvent) {
+  LOG("OnKeyReleaseEvent");
+  if (NS_WARN_IF(!KeymapWrapper::HandleKeyReleaseEvent(this, aEvent))) {
+    return FALSE;
+  }
+  return TRUE;
+}
+
+void nsWindow::OnScrollEvent(GdkEventScroll* aEvent) {
+  LOG("OnScrollEvent");
+
+  // check to see if we should rollup
+  if (CheckForRollup(aEvent->x_root, aEvent->y_root, true, false)) {
+    return;
+  }
+
+  // check for duplicate legacy scroll event, see GNOME bug 726878
+  if (aEvent->direction != GDK_SCROLL_SMOOTH &&
+      mLastScrollEventTime == aEvent->time) {
+    LOG("[%d] duplicate legacy scroll event %d\n", aEvent->time,
+        aEvent->direction);
+    return;
+  }
+  WidgetWheelEvent wheelEvent(true, eWheel, this);
+  wheelEvent.mDeltaMode = dom::WheelEvent_Binding::DOM_DELTA_LINE;
+  switch (aEvent->direction) {
+    case GDK_SCROLL_SMOOTH: {
+      // As of GTK 3.4, all directional scroll events are provided by
+      // the GDK_SCROLL_SMOOTH direction on XInput2 and Wayland devices.
+      mLastScrollEventTime = aEvent->time;
+
+      // Special handling for touchpads to support flings
+      // (also known as kinetic/inertial/momentum scrolling)
+      GdkDevice* device = gdk_event_get_source_device((GdkEvent*)aEvent);
+      GdkInputSource source = gdk_device_get_source(device);
+      if (source == GDK_SOURCE_TOUCHSCREEN || source == GDK_SOURCE_TOUCHPAD ||
+          mCurrentSynthesizedTouchpadPan.mTouchpadGesturePhase.isSome()) {
+        if (StaticPrefs::apz_gtk_pangesture_enabled() &&
+            gtk_check_version(3, 20, 0) == nullptr) {
+          static auto sGdkEventIsScrollStopEvent =
+              (gboolean(*)(const GdkEvent*))dlsym(
+                  RTLD_DEFAULT, "gdk_event_is_scroll_stop_event");
+
+          LOG("[%d] pan smooth event dx=%f dy=%f inprogress=%d\n", aEvent->time,
+              aEvent->delta_x, aEvent->delta_y, mPanInProgress);
+          auto eventType = PanGestureInput::PANGESTURE_PAN;
+          if (sGdkEventIsScrollStopEvent((GdkEvent*)aEvent)) {
+            eventType = PanGestureInput::PANGESTURE_END;
+            mPanInProgress = false;
+          } else if (!mPanInProgress) {
+            eventType = PanGestureInput::PANGESTURE_START;
+            mPanInProgress = true;
+          } else if (mCurrentSynthesizedTouchpadPan.mTouchpadGesturePhase
+                         .isSome()) {
+            switch (*mCurrentSynthesizedTouchpadPan.mTouchpadGesturePhase) {
+              case PHASE_BEGIN:
+                // we should never hit this because we'll hit the above case
+                // before this.
+                MOZ_ASSERT_UNREACHABLE();
+                eventType = PanGestureInput::PANGESTURE_START;
+                mPanInProgress = true;
+                break;
+              case PHASE_UPDATE:
+                // nothing to do here, eventtype should already be set
+                MOZ_ASSERT(mPanInProgress);
+                MOZ_ASSERT(eventType == PanGestureInput::PANGESTURE_PAN);
+                eventType = PanGestureInput::PANGESTURE_PAN;
+                break;
+              case PHASE_END:
+                MOZ_ASSERT(mPanInProgress);
+                eventType = PanGestureInput::PANGESTURE_END;
+                mPanInProgress = false;
+                break;
+              default:
+                MOZ_ASSERT_UNREACHABLE();
+                break;
+            }
+          }
+
+          mCurrentSynthesizedTouchpadPan.mTouchpadGesturePhase.reset();
+
+          const bool isPageMode =
+#ifdef NIGHTLY_BUILD
+              StaticPrefs::apz_gtk_pangesture_delta_mode() == 1;
+#else
+              StaticPrefs::apz_gtk_pangesture_delta_mode() != 2;
+#endif
+          const double multiplier =
+              isPageMode
+                  ? StaticPrefs::apz_gtk_pangesture_page_delta_mode_multiplier()
+                  : StaticPrefs::
+                            apz_gtk_pangesture_pixel_delta_mode_multiplier() *
+                        FractionalScaleFactor();
+
+          ScreenPoint deltas(float(aEvent->delta_x * multiplier),
+                             float(aEvent->delta_y * multiplier));
+
+          LayoutDeviceIntPoint touchPoint = GetRefPoint(this, aEvent);
+          PanGestureInput panEvent(
+              eventType, GetEventTimeStamp(aEvent->time),
+              ScreenPoint(touchPoint.x, touchPoint.y), deltas,
+              KeymapWrapper::ComputeKeyModifiers(aEvent->state));
+          panEvent.mDeltaType = isPageMode ? PanGestureInput::PANDELTA_PAGE
+                                           : PanGestureInput::PANDELTA_PIXEL;
+          panEvent.mSimulateMomentum =
+              StaticPrefs::apz_gtk_kinetic_scroll_enabled();
+
+          DispatchPanGesture(panEvent);
+
+          if (mCurrentSynthesizedTouchpadPan.mSavedObserver != 0) {
+            mozilla::widget::AutoObserverNotifier::NotifySavedObserver(
+                mCurrentSynthesizedTouchpadPan.mSavedObserver,
+                "touchpadpanevent");
+            mCurrentSynthesizedTouchpadPan.mSavedObserver = 0;
+          }
+
+          return;
+        }
+
+        // Older GTK doesn't support stop events, so we can't support fling
+        wheelEvent.mScrollType = WidgetWheelEvent::SCROLL_ASYNCHRONOUSLY;
+      }
+
+      // TODO - use a more appropriate scrolling unit than lines.
+      // Multiply event deltas by 3 to emulate legacy behaviour.
+      wheelEvent.mDeltaX = aEvent->delta_x * 3;
+      wheelEvent.mDeltaY = aEvent->delta_y * 3;
+      wheelEvent.mWheelTicksX = aEvent->delta_x;
+      wheelEvent.mWheelTicksY = aEvent->delta_y;
+      wheelEvent.mIsNoLineOrPageDelta = true;
+
+      break;
+    }
+    case GDK_SCROLL_UP:
+      wheelEvent.mDeltaY = wheelEvent.mLineOrPageDeltaY = -3;
+      wheelEvent.mWheelTicksY = -1;
+      break;
+    case GDK_SCROLL_DOWN:
+      wheelEvent.mDeltaY = wheelEvent.mLineOrPageDeltaY = 3;
+      wheelEvent.mWheelTicksY = 1;
+      break;
+    case GDK_SCROLL_LEFT:
+      wheelEvent.mDeltaX = wheelEvent.mLineOrPageDeltaX = -1;
+      wheelEvent.mWheelTicksX = -1;
+      break;
+    case GDK_SCROLL_RIGHT:
+      wheelEvent.mDeltaX = wheelEvent.mLineOrPageDeltaX = 1;
+      wheelEvent.mWheelTicksX = 1;
+      break;
+  }
+
+  wheelEvent.mRefPoint = GetRefPoint(this, aEvent);
+
+  KeymapWrapper::InitInputEvent(wheelEvent, aEvent->state);
+
+  wheelEvent.AssignEventTime(GetWidgetEventTime(aEvent->time));
+
+  DispatchInputEvent(&wheelEvent);
+}
+
+void nsWindow::DispatchPanGesture(PanGestureInput& aPanInput) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (mSwipeTracker) {
+    // Give the swipe tracker a first pass at the event. If a new pan gesture
+    // has been started since the beginning of the swipe, the swipe tracker
+    // will know to ignore the event.
+    nsEventStatus status = mSwipeTracker->ProcessEvent(aPanInput);
+    if (status == nsEventStatus_eConsumeNoDefault) {
+      return;
+    }
+  }
+
+  APZEventResult result;
+  if (mAPZC) {
+    MOZ_ASSERT(APZThreadUtils::IsControllerThread());
+
+    result = mAPZC->InputBridge()->ReceiveInputEvent(aPanInput);
+    if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+      return;
+    }
+  }
+
+  WidgetWheelEvent event = aPanInput.ToWidgetEvent(this);
+  if (!mAPZC) {
+    if (MayStartSwipeForNonAPZ(aPanInput)) {
+      return;
+    }
+  } else {
+    event = MayStartSwipeForAPZ(aPanInput, result);
+  }
+
+  ProcessUntransformedAPZEvent(&event, result);
+}
+
+void nsWindow::OnVisibilityNotifyEvent(GdkVisibilityState aState) {
+  LOG("nsWindow::OnVisibilityNotifyEvent [%p] state 0x%x\n", this, aState);
+  auto state = aState == GDK_VISIBILITY_FULLY_OBSCURED
+                   ? OcclusionState::OCCLUDED
+                   : OcclusionState::UNKNOWN;
+  NotifyOcclusionState(state);
+}
+
+void nsWindow::OnWindowStateEvent(GtkWidget* aWidget,
+                                  GdkEventWindowState* aEvent) {
+  LOG("nsWindow::OnWindowStateEvent for %p changed 0x%x new_window_state "
+      "0x%x\n",
+      aWidget, aEvent->changed_mask, aEvent->new_window_state);
+
+  if (IS_MOZ_CONTAINER(aWidget)) {
+    // This event is notifying the container widget of changes to the
+    // toplevel window.  Just detect changes affecting whether windows are
+    // viewable.
+    //
+    // (A visibility notify event is sent to each window that becomes
+    // viewable when the toplevel is mapped, but we can't rely on that for
+    // setting mHasMappedToplevel because these toplevel window state
+    // events are asynchronous.  The windows in the hierarchy now may not
+    // be the same windows as when the toplevel was mapped, so they may
+    // not get VisibilityNotify events.)
+    bool mapped = !(aEvent->new_window_state &
+                    (GDK_WINDOW_STATE_ICONIFIED | GDK_WINDOW_STATE_WITHDRAWN));
+    SetHasMappedToplevel(mapped);
+    LOG("\tquick return because IS_MOZ_CONTAINER(aWidget) is true\n");
+    return;
+  }
+  // else the widget is a shell widget.
+
+  // The block below is a bit evil.
+  //
+  // When a window is resized before it is shown, gtk_window_resize() delays
+  // resizes until the window is shown.  If gtk_window_state_event() sees a
+  // GDK_WINDOW_STATE_MAXIMIZED change [1] before the window is shown, then
+  // gtk_window_compute_configure_request_size() ignores the values from the
+  // resize [2].  See bug 1449166 for an example of how this could happen.
+  //
+  // [1] https://gitlab.gnome.org/GNOME/gtk/blob/3.22.30/gtk/gtkwindow.c#L7967
+  // [2] https://gitlab.gnome.org/GNOME/gtk/blob/3.22.30/gtk/gtkwindow.c#L9377
+  //
+  // In order to provide a sensible size for the window when the user exits
+  // maximized state, we hide the GDK_WINDOW_STATE_MAXIMIZED change from
+  // gtk_window_state_event() so as to trick GTK into using the values from
+  // gtk_window_resize() in its configure request.
+  //
+  // We instead notify gtk_window_state_event() of the maximized state change
+  // once the window is shown.
+  //
+  // See https://gitlab.gnome.org/GNOME/gtk/issues/1044
+  //
+  // This may be fixed in Gtk 3.24+ but it's still live and kicking
+  // (Bug 1791779).
+  if (!mIsShown) {
+    aEvent->changed_mask = static_cast<GdkWindowState>(
+        aEvent->changed_mask & ~GDK_WINDOW_STATE_MAXIMIZED);
+  } else if (aEvent->changed_mask & GDK_WINDOW_STATE_WITHDRAWN &&
+             aEvent->new_window_state & GDK_WINDOW_STATE_MAXIMIZED) {
+    aEvent->changed_mask = static_cast<GdkWindowState>(
+        aEvent->changed_mask | GDK_WINDOW_STATE_MAXIMIZED);
+  }
+
+  // This is a workaround for https://gitlab.gnome.org/GNOME/gtk/issues/1395
+  // Gtk+ controls window active appearance by window-state-event signal.
+  if (IsChromeWindowTitlebar() &&
+      (aEvent->changed_mask & GDK_WINDOW_STATE_FOCUSED)) {
+    // Emulate what Gtk+ does at gtk_window_state_event().
+    // We can't check GTK_STATE_FLAG_BACKDROP directly as it's set by Gtk+
+    // *after* this window-state-event handler.
+    mTitlebarBackdropState =
+        !(aEvent->new_window_state & GDK_WINDOW_STATE_FOCUSED);
+
+    // keep IsActiveBrowserWindow in sync with GDK_WINDOW_STATE_FOCUSED
+    UpdateMozWindowActive();
+
+    ForceTitlebarRedraw();
+  }
+
+  // We don't care about anything but changes in the maximized/icon/fullscreen
+  // states but we need a workaround for bug in Wayland:
+  // https://gitlab.gnome.org/GNOME/gtk/issues/67
+  // Under wayland the gtk_window_iconify implementation does NOT synthetize
+  // window_state_event where the GDK_WINDOW_STATE_ICONIFIED is set.
+  // During restore we  won't get aEvent->changed_mask with
+  // the GDK_WINDOW_STATE_ICONIFIED so to detect that change we use the stored
+  // mSizeMode and obtaining a focus.
+  bool waylandWasIconified =
+      (GdkIsWaylandDisplay() &&
+       aEvent->changed_mask & GDK_WINDOW_STATE_FOCUSED &&
+       aEvent->new_window_state & GDK_WINDOW_STATE_FOCUSED &&
+       mSizeMode == nsSizeMode_Minimized);
+  if (!waylandWasIconified &&
+      (aEvent->changed_mask &
+       (GDK_WINDOW_STATE_ICONIFIED | GDK_WINDOW_STATE_MAXIMIZED |
+        GDK_WINDOW_STATE_TILED | GDK_WINDOW_STATE_FULLSCREEN)) == 0) {
+    LOG("\tearly return because no interesting bits changed\n");
+    return;
+  }
+
+  auto oldSizeMode = mSizeMode;
+  if (aEvent->new_window_state & GDK_WINDOW_STATE_ICONIFIED) {
+    LOG("\tIconified\n");
+    mSizeMode = nsSizeMode_Minimized;
+#ifdef ACCESSIBILITY
+    DispatchMinimizeEventAccessible();
+#endif  // ACCESSIBILITY
+  } else if (aEvent->new_window_state & GDK_WINDOW_STATE_FULLSCREEN) {
+    LOG("\tFullscreen\n");
+    mSizeMode = nsSizeMode_Fullscreen;
+  } else if (aEvent->new_window_state & GDK_WINDOW_STATE_MAXIMIZED) {
+    LOG("\tMaximized\n");
+    mSizeMode = nsSizeMode_Maximized;
+#ifdef ACCESSIBILITY
+    DispatchMaximizeEventAccessible();
+#endif  // ACCESSIBILITY
+  } else {
+    LOG("\tNormal\n");
+    mSizeMode = nsSizeMode_Normal;
+#ifdef ACCESSIBILITY
+    DispatchRestoreEventAccessible();
+#endif  // ACCESSIBILITY
+  }
+
+  mIsTiled = aEvent->new_window_state & GDK_WINDOW_STATE_TILED;
+  LOG("\tTiled: %d\n", int(mIsTiled));
+
+  if (mWidgetListener && mSizeMode != oldSizeMode) {
+    mWidgetListener->SizeModeChanged(mSizeMode);
+  }
+
+  if (mDrawInTitlebar && mTransparencyBitmapForTitlebar) {
+    if (mSizeMode == nsSizeMode_Normal && !mIsTiled) {
+      UpdateTitlebarTransparencyBitmap();
+    } else {
+      ClearTransparencyBitmap();
+    }
+  } else {
+    SetTitlebarRect();
+  }
+}
+
+void nsWindow::OnDPIChanged() {
+  // Update menu's font size etc.
+  // This affects style / layout because it affects system font sizes.
+  if (mWidgetListener) {
+    if (PresShell* presShell = mWidgetListener->GetPresShell()) {
+      presShell->BackingScaleFactorChanged();
+    }
+    mWidgetListener->UIResolutionChanged();
+  }
+}
+
+void nsWindow::OnCheckResize() { mPendingConfigures++; }
+
+void nsWindow::OnCompositedChanged() {
+  // Update CSD after the change in alpha visibility. This only affects
+  // system metrics, not other theme shenanigans.
+  NotifyThemeChanged(ThemeChangeKind::MediaQueriesOnly);
+  mCompositedScreen = gdk_screen_is_composited(gdk_screen_get_default());
+}
+
+void nsWindow::OnScaleChanged(bool aNotify) {
+  if (!IsTopLevelWindowType()) {
+    return;
+  }
+  if (!mGdkWindow) {
+    return;  // We'll get there again when we configure the window.
+  }
+  gint newCeiled = gdk_window_get_scale_factor(mGdkWindow);
+  double newFractional = [&] {
+#ifdef MOZ_WAYLAND
+    if (GdkIsWaylandDisplay()) {
+      return moz_container_wayland_get_fractional_scale(mContainer);
+    }
+#endif
+    return 0.0;
+  }();
+
+  if (mCeiledScaleFactor == newCeiled &&
+      mFractionalScaleFactor == newFractional) {
+    return;
+  }
+
+  LOG("OnScaleChanged %d, %f -> %d, %f\n", int(mCeiledScaleFactor),
+      mFractionalScaleFactor, newCeiled, newFractional);
+
+  mCeiledScaleFactor = newCeiled;
+  mFractionalScaleFactor = newFractional;
+
+  if (!aNotify) {
+    return;
+  }
+
+  // We pause compositor to avoid rendering of obsoleted remote content which
+  // produces flickering.
+  // Re-enable compositor again when remote content is updated or timeout
+  // happens.
+  PauseCompositorFlickering();
+
+  GtkAllocation allocation;
+  gtk_widget_get_allocation(GTK_WIDGET(mContainer), &allocation);
+  LayoutDeviceIntSize size = GdkRectToDevicePixels(allocation).Size();
+  mBounds.SizeTo(size);
+  // Check mBounds size
+  if (mCompositorSession &&
+      !wr::WindowSizeSanityCheck(mBounds.width, mBounds.height)) {
+    gfxCriticalNoteOnce << "Invalid mBounds in OnScaleChanged " << mBounds;
+  }
+
+  if (mWidgetListener) {
+    if (PresShell* presShell = mWidgetListener->GetPresShell()) {
+      presShell->BackingScaleFactorChanged();
+    }
+  }
+
+  DispatchResized();
+
+  if (mCompositorWidgetDelegate) {
+    mCompositorWidgetDelegate->NotifyClientSizeChanged(GetClientSize());
+  }
+
+  if (mCursor.IsCustom()) {
+    mUpdateCursor = true;
+    SetCursor(Cursor{mCursor});
+  }
+}
+
+void nsWindow::DispatchDragEvent(EventMessage aMsg,
+                                 const LayoutDeviceIntPoint& aRefPoint,
+                                 guint aTime) {
+  LOGDRAG("nsWindow::DispatchDragEvent");
+  WidgetDragEvent event(true, aMsg, this);
+
+  InitDragEvent(event);
+
+  event.mRefPoint = aRefPoint;
+  event.AssignEventTime(GetWidgetEventTime(aTime));
+
+  DispatchInputEvent(&event);
+}
+
+void nsWindow::OnDragDataReceivedEvent(GtkWidget* aWidget,
+                                       GdkDragContext* aDragContext, gint aX,
+                                       gint aY,
+                                       GtkSelectionData* aSelectionData,
+                                       guint aInfo, guint aTime,
+                                       gpointer aData) {
+  LOGDRAG("nsWindow::OnDragDataReceived");
+
+  RefPtr<nsDragService> dragService = nsDragService::GetInstance();
+  nsDragService::AutoEventLoop loop(dragService);
+  dragService->TargetDataReceived(aWidget, aDragContext, aX, aY, aSelectionData,
+                                  aInfo, aTime);
+}
+
+nsWindow* nsWindow::GetTransientForWindowIfPopup() {
+  if (mWindowType != WindowType::Popup) {
+    return nullptr;
+  }
+  GtkWindow* toplevel = gtk_window_get_transient_for(GTK_WINDOW(mShell));
+  if (toplevel) {
+    return get_window_for_gtk_widget(GTK_WIDGET(toplevel));
+  }
+  return nullptr;
+}
+
+bool nsWindow::IsHandlingTouchSequence(GdkEventSequence* aSequence) {
+  return mHandleTouchEvent && mTouches.Contains(aSequence);
+}
+
+gboolean nsWindow::OnTouchpadPinchEvent(GdkEventTouchpadPinch* aEvent) {
+  if (!StaticPrefs::apz_gtk_touchpad_pinch_enabled()) {
+    return TRUE;
+  }
+  // Do not respond to pinch gestures involving more than two fingers
+  // unless specifically preffed on. These are sometimes hooked up to other
+  // actions at the desktop environment level and having the browser also
+  // pinch can be undesirable.
+  if (aEvent->n_fingers > 2 &&
+      !StaticPrefs::apz_gtk_touchpad_pinch_three_fingers_enabled()) {
+    return FALSE;
+  }
+  auto pinchGestureType = PinchGestureInput::PINCHGESTURE_SCALE;
+  ScreenCoord currentSpan;
+  ScreenCoord previousSpan;
+
+  switch (aEvent->phase) {
+    case GDK_TOUCHPAD_GESTURE_PHASE_BEGIN:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_START;
+      currentSpan = aEvent->scale;
+      mCurrentTouchpadFocus = ViewAs<ScreenPixel>(
+          GetRefPoint(this, aEvent),
+          PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+
+      // Assign PreviousSpan --> 0.999 to make mDeltaY field of the
+      // WidgetWheelEvent that this PinchGestureInput event will be converted
+      // to not equal Zero as our discussion because we observed that the
+      // scale of the PHASE_BEGIN event is 1.
+      previousSpan = 0.999;
+      break;
+
+    case GDK_TOUCHPAD_GESTURE_PHASE_UPDATE:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_SCALE;
+      mCurrentTouchpadFocus += ScreenPoint(aEvent->dx, aEvent->dy);
+      if (aEvent->scale == mLastPinchEventSpan) {
+        return FALSE;
+      }
+      currentSpan = aEvent->scale;
+      previousSpan = mLastPinchEventSpan;
+      break;
+
+    case GDK_TOUCHPAD_GESTURE_PHASE_END:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_END;
+      currentSpan = aEvent->scale;
+      previousSpan = mLastPinchEventSpan;
+      break;
+
+    default:
+      return FALSE;
+  }
+
+  PinchGestureInput event(
+      pinchGestureType, PinchGestureInput::TRACKPAD,
+      GetEventTimeStamp(aEvent->time), ExternalPoint(0, 0),
+      mCurrentTouchpadFocus,
+      100.0 * ((aEvent->phase == GDK_TOUCHPAD_GESTURE_PHASE_END)
+                   ? ScreenCoord(1.f)
+                   : currentSpan),
+      100.0 * ((aEvent->phase == GDK_TOUCHPAD_GESTURE_PHASE_END)
+                   ? ScreenCoord(1.f)
+                   : previousSpan),
+      KeymapWrapper::ComputeKeyModifiers(aEvent->state));
+
+  if (!event.SetLineOrPageDeltaY(this)) {
+    return FALSE;
+  }
+
+  mLastPinchEventSpan = aEvent->scale;
+  DispatchPinchGestureInput(event);
+  return TRUE;
+}
+
+gboolean nsWindow::OnTouchEvent(GdkEventTouch* aEvent) {
+  LOG("OnTouchEvent: x=%f y=%f type=%d\n", aEvent->x, aEvent->y, aEvent->type);
+  if (!mHandleTouchEvent) {
+    // If a popup window was spawned (e.g. as the result of a long-press)
+    // and touch events got diverted to that window within a touch sequence,
+    // ensure the touch event gets sent to the original window instead. We
+    // keep the checks here very conservative so that we only redirect
+    // events in this specific scenario.
+    nsWindow* targetWindow = GetTransientForWindowIfPopup();
+    if (targetWindow &&
+        targetWindow->IsHandlingTouchSequence(aEvent->sequence)) {
+      return targetWindow->OnTouchEvent(aEvent);
+    }
+
+    return FALSE;
+  }
+
+  EventMessage msg;
+  switch (aEvent->type) {
+    case GDK_TOUCH_BEGIN:
+      // check to see if we should rollup
+      if (CheckForRollup(aEvent->x_root, aEvent->y_root, false, false)) {
+        return FALSE;
+      }
+      msg = eTouchStart;
+      break;
+    case GDK_TOUCH_UPDATE:
+      msg = eTouchMove;
+      // Start dragging when motion events happens in the dragging area
+      if (mWindowShouldStartDragging) {
+        mWindowShouldStartDragging = false;
+        if (mGdkWindow) {
+          GdkWindow* gdk_window = gdk_window_get_toplevel(mGdkWindow);
+          MOZ_ASSERT(gdk_window,
+                     "gdk_window_get_toplevel should not return null");
+
+          LOG("  start window dragging window\n");
+          gdk_window_begin_move_drag(gdk_window, 1, aEvent->x_root,
+                                     aEvent->y_root, aEvent->time);
+
+          // Cancel the event sequence. gdk will steal all subsequent events
+          // (including TOUCH_END).
+          msg = eTouchCancel;
+        }
+      }
+      break;
+    case GDK_TOUCH_END:
+      msg = eTouchEnd;
+      if (mWindowShouldStartDragging) {
+        LOG("  end of window dragging window\n");
+        mWindowShouldStartDragging = false;
+      }
+      break;
+    case GDK_TOUCH_CANCEL:
+      msg = eTouchCancel;
+      break;
+    default:
+      return FALSE;
+  }
+
+  const LayoutDeviceIntPoint touchPoint = GetRefPoint(this, aEvent);
+
+  int32_t id;
+  RefPtr<dom::Touch> touch;
+  if (mTouches.Remove(aEvent->sequence, getter_AddRefs(touch))) {
+    id = touch->mIdentifier;
+  } else {
+    id = ++gLastTouchID & 0x7FFFFFFF;
+  }
+
+  touch =
+      new dom::Touch(id, touchPoint, LayoutDeviceIntPoint(1, 1), 0.0f, 0.0f);
+
+  WidgetTouchEvent event(true, msg, this);
+  KeymapWrapper::InitInputEvent(event, aEvent->state);
+
+  if (msg == eTouchStart || msg == eTouchMove) {
+    mTouches.InsertOrUpdate(aEvent->sequence, std::move(touch));
+    // add all touch points to event object
+    for (const auto& data : mTouches.Values()) {
+      event.mTouches.AppendElement(new dom::Touch(*data));
+    }
+  } else if (msg == eTouchEnd || msg == eTouchCancel) {
+    *event.mTouches.AppendElement() = std::move(touch);
+  }
+
+  nsIWidget::ContentAndAPZEventStatus eventStatus = DispatchInputEvent(&event);
+
+  // There's a chance that we are in drag area and the event is not consumed
+  // by something on it.
+  if (msg == eTouchStart && mDraggableRegion.Contains(touchPoint) &&
+      eventStatus.mApzStatus != nsEventStatus_eConsumeNoDefault) {
+    mWindowShouldStartDragging = true;
+  }
+  return TRUE;
+}
+
+// Return true if toplevel window is transparent.
+// It's transparent when we're running on composited screens
+// and we can draw main window without system titlebar.
+bool nsWindow::IsToplevelWindowTransparent() {
+  static bool transparencyConfigured = false;
+
+  if (!transparencyConfigured) {
+    if (gdk_screen_is_composited(gdk_screen_get_default())) {
+      // Some Gtk+ themes use non-rectangular toplevel windows. To fully
+      // support such themes we need to make toplevel window transparent
+      // with ARGB visual.
+      // It may cause performanance issue so make it configurable
+      // and enable it by default for selected window managers.
+      if (Preferences::HasUserValue("mozilla.widget.use-argb-visuals")) {
+        // argb visual is explicitly required so use it
+        sTransparentMainWindow =
+            Preferences::GetBool("mozilla.widget.use-argb-visuals");
+      } else {
+        // Enable transparent toplevel window if we can draw main window
+        // without system titlebar as Gtk+ themes use titlebar round corners.
+        sTransparentMainWindow =
+            GetSystemGtkWindowDecoration() != GTK_DECORATION_NONE;
+      }
+    }
+    transparencyConfigured = true;
+  }
+
+  return sTransparentMainWindow;
+}
+
+#ifdef MOZ_X11
+// Configure GL visual on X11.
+bool nsWindow::ConfigureX11GLVisual() {
+  auto* screen = gtk_widget_get_screen(mShell);
+  int visualId = 0;
+  bool haveVisual = false;
+
+  if (gfxVars::UseEGL()) {
+    haveVisual = GLContextEGL::FindVisual(&visualId);
+  }
+
+  // We are on GLX or use it as a fallback on Mesa, see
+  // https://gitlab.freedesktop.org/mesa/mesa/-/issues/149
+  if (!haveVisual) {
+    auto* display = GDK_DISPLAY_XDISPLAY(gtk_widget_get_display(mShell));
+    int screenNumber = GDK_SCREEN_XNUMBER(screen);
+    haveVisual = GLContextGLX::FindVisual(display, screenNumber, &visualId);
+  }
+
+  GdkVisual* gdkVisual = nullptr;
+  if (haveVisual) {
+    // If we're using CSD, rendering will go through mContainer, but
+    // it will inherit this visual as it is a child of mShell.
+    gdkVisual = gdk_x11_screen_lookup_visual(screen, visualId);
+  }
+  if (!gdkVisual) {
+    NS_WARNING("We're missing X11 Visual!");
+    // We try to use a fallback alpha visual
+    GdkScreen* screen = gtk_widget_get_screen(mShell);
+    gdkVisual = gdk_screen_get_rgba_visual(screen);
+  }
+  if (gdkVisual) {
+    gtk_widget_set_visual(mShell, gdkVisual);
+    mHasAlphaVisual = true;
+    return true;
+  }
+
+  return false;
+}
+#endif
+
+nsAutoCString nsWindow::GetFrameTag() const {
+  if (nsIFrame* frame = GetFrame()) {
+#ifdef DEBUG_FRAME_DUMP
+    return frame->ListTag();
+#else
+    nsAutoCString buf;
+    buf.AppendPrintf("Frame(%p)", frame);
+    if (nsIContent* content = frame->GetContent()) {
+      buf.Append(' ');
+      AppendUTF16toUTF8(content->NodeName(), buf);
+    }
+    return buf;
+#endif
+  }
+  return nsAutoCString("(no frame)");
+}
+
+nsCString nsWindow::GetPopupTypeName() {
+  switch (mPopupType) {
+    case PopupType::Menu:
+      return nsCString("Menu");
+    case PopupType::Tooltip:
+      return nsCString("Tooltip");
+    case PopupType::Panel:
+      return nsCString("Panel/Utility");
+    default:
+      return nsCString("Unknown");
+  }
+}
+
+// Disables all rendering of GtkWidget from Gtk side.
+// We do our best to persuade Gtk/Gdk to ignore all painting
+// to the widget.
+static void GtkWidgetDisableUpdates(GtkWidget* aWidget) {
+  // Clear exposure mask - it disabled synthesized events.
+  GdkWindow* window = gtk_widget_get_window(aWidget);
+  if (!window) {
+    return;
+  }
+  gdk_window_set_events(window, (GdkEventMask)(gdk_window_get_events(window) &
+                                               (~GDK_EXPOSURE_MASK)));
+
+  // Remove before/after paint handles from frame clock.
+  // It disables widget content updates.
+  GdkFrameClock* frame_clock = gdk_window_get_frame_clock(window);
+  g_signal_handlers_disconnect_by_data(frame_clock, window);
+}
+
+Window nsWindow::GetX11Window() {
+#ifdef MOZ_X11
+  if (GdkIsX11Display()) {
+    return mGdkWindow ? gdk_x11_window_get_xid(mGdkWindow) : X11None;
+  }
+#endif
+  return (Window) nullptr;
+}
+
+void nsWindow::EnsureGdkWindow() {
+  MOZ_DIAGNOSTIC_ASSERT(mIsMapped);
+  if (!mGdkWindow) {
+    mGdkWindow = gtk_widget_get_window(GTK_WIDGET(mContainer));
+    g_object_set_data(G_OBJECT(mGdkWindow), "nsWindow", this);
+    if (mIMContext) {
+      mIMContext->SetGdkWindow(mGdkWindow);
+    }
+  }
+}
+
+bool nsWindow::GetShapedState() {
+  return mIsTransparent && !mHasAlphaVisual && !mTransparencyBitmapForTitlebar;
+}
+
+void nsWindow::ConfigureCompositor() {
+  MOZ_DIAGNOSTIC_ASSERT(mCompositorState == COMPOSITOR_ENABLED);
+  MOZ_DIAGNOSTIC_ASSERT(mIsMapped);
+
+  LOG("nsWindow::ConfigureCompositor()");
+  auto startCompositing = [self = RefPtr{this}, this]() -> void {
+    LOG("  moz_container_wayland_add_or_fire_initial_draw_callback "
+        "ConfigureCompositor");
+
+    // too late
+    if (mIsDestroyed || !mIsMapped) {
+      LOG("  quit, mIsDestroyed = %d mIsMapped = %d", !!mIsDestroyed,
+          mIsMapped);
+      return;
+    }
+    // Compositor will be resumed later by ResumeCompositorFlickering().
+    if (mCompositorState == COMPOSITOR_PAUSED_FLICKERING) {
+      LOG("  quit, will be resumed by ResumeCompositorFlickering.");
+      return;
+    }
+    // Compositor will be resumed at nsWindow::SetCompositorWidgetDelegate().
+    if (!mCompositorWidgetDelegate) {
+      LOG("  quit, missing mCompositorWidgetDelegate");
+      return;
+    }
+
+    ResumeCompositorImpl();
+  };
+
+  if (GdkIsWaylandDisplay()) {
+#ifdef MOZ_WAYLAND
+    moz_container_wayland_add_or_fire_initial_draw_callback(mContainer,
+                                                            startCompositing);
+#endif
+  } else {
+    startCompositing();
+  }
+}
+
+void nsWindow::ConfigureGdkWindow() {
+  LOG("nsWindow::ConfigureGdkWindow()");
+
+  EnsureGdkWindow();
+  OnScaleChanged(/* aNotify = */ false);
+
+#ifdef MOZ_X11
+  if (GdkIsX11Display()) {
+    GdkVisual* gdkVisual = gdk_window_get_visual(mGdkWindow);
+    Visual* visual = gdk_x11_visual_get_xvisual(gdkVisual);
+    int depth = gdk_visual_get_depth(gdkVisual);
+    mSurfaceProvider.Initialize(GetX11Window(), visual, depth,
+                                GetShapedState());
+
+    // Set window manager hint to keep fullscreen windows composited.
+    //
+    // If the window were to get unredirected, there could be visible
+    // tearing because Gecko does not align its framebuffer updates with
+    // vblank.
+    SetCompositorHint(GTK_WIDGET_COMPOSIDED_ENABLED);
+  }
+#endif
+#ifdef MOZ_WAYLAND
+  if (GdkIsWaylandDisplay()) {
+    mSurfaceProvider.Initialize(this);
+  }
+#endif
+
+  if (mIsDragPopup) {
+    if (GdkIsWaylandDisplay()) {
+      // Disable painting to the widget on Wayland as we paint directly to the
+      // widget. Wayland compositors does not paint wl_subsurface
+      // of D&D widget.
+      if (GtkWidget* parent = gtk_widget_get_parent(mShell)) {
+        GtkWidgetDisableUpdates(parent);
+      }
+      GtkWidgetDisableUpdates(mShell);
+      GtkWidgetDisableUpdates(GTK_WIDGET(mContainer));
+    } else {
+      // Disable rendering of parent container on X11 to avoid flickering.
+      if (GtkWidget* parent = gtk_widget_get_parent(mShell)) {
+        gtk_widget_set_opacity(parent, 0.0);
+      }
+    }
+  }
+
+  if (mWindowType == WindowType::Popup) {
+    if (mNoAutoHide) {
+      gint wmd = ConvertBorderStyles(mBorderStyle);
+      if (wmd != -1) {
+        gdk_window_set_decorations(mGdkWindow, (GdkWMDecoration)wmd);
+      }
+    }
+    // If the popup ignores mouse events, set an empty input shape.
+    SetInputRegion(mInputRegion);
+  }
+
+  RefreshWindowClass();
+
+  // We're not mapped yet but we have already created compositor.
+  if (mCompositorWidgetDelegate) {
+    ConfigureCompositor();
+  }
+
+  LOG("  finished, new GdkWindow %p XID 0x%lx\n", mGdkWindow, GetX11Window());
+}
+
+nsresult nsWindow::Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                          const LayoutDeviceIntRect& aRect,
+                          widget::InitData* aInitData) {
+  LOG("nsWindow::Create\n");
+
+  // only set the base parent if we're going to be a dialog or a
+  // toplevel
+  nsIWidget* baseParent =
+      aInitData && (aInitData->mWindowType == WindowType::Dialog ||
+                    aInitData->mWindowType == WindowType::TopLevel ||
+                    aInitData->mWindowType == WindowType::Invisible)
+          ? nullptr
+          : aParent;
+
+#ifdef ACCESSIBILITY
+  // Send a DBus message to check whether a11y is enabled
+  a11y::PreInit();
+#endif
+
+#ifdef MOZ_WAYLAND
+  // Ensure that KeymapWrapper is created on Wayland as we need it for
+  // keyboard focus tracking.
+  if (GdkIsWaylandDisplay()) {
+    KeymapWrapper::EnsureInstance();
+  }
+#endif
+
+  // Ensure that the toolkit is created.
+  nsGTKToolkit::GetToolkit();
+
+  // initialize all the common bits of this class
+  BaseCreate(baseParent, aInitData);
+
+  // and do our common creation
+  mParent = aParent;
+  // save our bounds
+  mBounds = aRect;
+  LOG("  mBounds: x:%d y:%d w:%d h:%d\n", mBounds.x, mBounds.y, mBounds.width,
+      mBounds.height);
+
+  ConstrainSize(&mBounds.width, &mBounds.height);
+  mLastSizeRequest = mBounds.Size();
+
+  bool popupNeedsAlphaVisual = mWindowType == WindowType::Popup &&
+                               (aInitData && aInitData->mTransparencyMode ==
+                                                 TransparencyMode::Transparent);
+
+  // Figure out our parent window - only used for WindowType::Child
+  nsWindow* parentnsWindow = nullptr;
+
+  if (aParent) {
+    parentnsWindow = static_cast<nsWindow*>(aParent);
+  } else if (aNativeParent && GDK_IS_WINDOW(aNativeParent)) {
+    parentnsWindow = get_window_for_gdk_window(GDK_WINDOW(aNativeParent));
+    if (!parentnsWindow) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  if (mWindowType == WindowType::Child) {
+    // We don't support WindowType::Child directly but emulate it by popup
+    // windows.
+    mWindowType = WindowType::Popup;
+    if (!parentnsWindow) {
+      if (aNativeParent && GTK_IS_CONTAINER(aNativeParent)) {
+        parentnsWindow = get_window_for_gtk_widget(GTK_WIDGET(aNativeParent));
+      }
+    }
+    mIsChildWindow = true;
+    LOG("  child widget, switch to popup. parent nsWindow %p", parentnsWindow);
+  }
+
+  MOZ_ASSERT_IF(mWindowType == WindowType::Popup, parentnsWindow);
+
+  if (mWindowType != WindowType::Dialog && mWindowType != WindowType::Popup &&
+      mWindowType != WindowType::TopLevel &&
+      mWindowType != WindowType::Invisible) {
+    MOZ_ASSERT_UNREACHABLE("Unexpected eWindowType");
+    return NS_ERROR_FAILURE;
+  }
+
+  mAlwaysOnTop = aInitData && aInitData->mAlwaysOnTop;
+  // mNoAutoHide seems to be always false here.
+  // The mNoAutoHide state is set later on nsMenuPopupFrame level
+  // and can be changed so we use WaylandPopupIsPermanent() to get
+  // recent popup config (Bug 1728952).
+  mNoAutoHide = aInitData && aInitData->mNoAutoHide;
+
+  // Popups that are not noautohide are only temporary. The are used
+  // for menus and the like and disappear when another window is used.
+  // For most popups, use the standard GtkWindowType GTK_WINDOW_POPUP,
+  // which will use a Window with the override-redirect attribute
+  // (for temporary windows).
+  // For long-lived windows, their stacking order is managed by the
+  // window manager, as indicated by GTK_WINDOW_TOPLEVEL.
+  // For Wayland we have to always use GTK_WINDOW_POPUP to control
+  // popup window position.
+  GtkWindowType type = GTK_WINDOW_TOPLEVEL;
+  if (mWindowType == WindowType::Popup) {
+    MOZ_ASSERT(aInitData);
+    type = GTK_WINDOW_POPUP;
+    if (GdkIsX11Display() && mNoAutoHide) {
+      type = GTK_WINDOW_TOPLEVEL;
+    }
+  }
+  mShell = gtk_window_new(type);
+
+  // Ensure gfxPlatform is initialized, since that is what initializes
+  // gfxVars, used below.
+  Unused << gfxPlatform::GetPlatform();
+
+  if (IsTopLevelWindowType()) {
+    mGtkWindowDecoration = GetSystemGtkWindowDecoration();
+    // Inherit initial scale from our parent, or use the default monitor scale
+    // otherwise.
+    mCeiledScaleFactor = parentnsWindow
+                             ? int32_t(parentnsWindow->mCeiledScaleFactor)
+                             : ScreenHelperGTK::GetGTKMonitorScaleFactor();
+  }
+
+  // Don't use transparency for PictureInPicture windows.
+  bool toplevelNeedsAlphaVisual = false;
+  if (mWindowType == WindowType::TopLevel && !mIsPIPWindow) {
+    toplevelNeedsAlphaVisual = IsToplevelWindowTransparent();
+  }
+
+  bool isGLVisualSet = false;
+  mIsAccelerated = ComputeShouldAccelerate();
+#ifdef MOZ_X11
+  if (GdkIsX11Display() && mIsAccelerated) {
+    isGLVisualSet = ConfigureX11GLVisual();
+  }
+#endif
+  if (!isGLVisualSet && (popupNeedsAlphaVisual || toplevelNeedsAlphaVisual)) {
+    // We're running on composited screen so we can use alpha visual
+    // for both toplevel and popups.
+    if (mCompositedScreen) {
+      GdkVisual* visual =
+          gdk_screen_get_rgba_visual(gtk_widget_get_screen(mShell));
+      if (visual) {
+        gtk_widget_set_visual(mShell, visual);
+        mHasAlphaVisual = true;
+      }
+    }
+  }
+
+  // Use X shape mask to draw round corners of Firefox titlebar.
+  // We don't use shape masks any more as we switched to ARGB visual
+  // by default and non-compositing screens use solid-csd decorations
+  // without round corners.
+  // Leave the shape mask code here as it can be used to draw round
+  // corners on EGL (https://gitlab.freedesktop.org/mesa/mesa/-/issues/149)
+  // or when custom titlebar theme is used.
+  mTransparencyBitmapForTitlebar = TitlebarUseShapeMask();
+
+  // We have a toplevel window with transparency.
+  // Calls to UpdateTitlebarTransparencyBitmap() from OnExposeEvent()
+  // occur before SetTransparencyMode() receives TransparencyMode::Transparent
+  // from layout, so set mIsTransparent here.
+  if (mWindowType == WindowType::TopLevel &&
+      (mHasAlphaVisual || mTransparencyBitmapForTitlebar)) {
+    mIsTransparent = true;
+  }
+
+  // We only move a general managed toplevel window if someone has
+  // actually placed the window somewhere.  If no placement has taken
+  // place, we just let the window manager Do The Right Thing.
+  if (AreBoundsSane()) {
+    GdkRectangle size = DevicePixelsToGdkSizeRoundUp(mBounds.Size());
+    LOG("nsWindow::Create() Initial resize to %d x %d\n", size.width,
+        size.height);
+    gtk_window_resize(GTK_WINDOW(mShell), size.width, size.height);
+  }
+  if (mIsPIPWindow) {
+    LOG("    Is PIP window\n");
+    gtk_window_set_type_hint(GTK_WINDOW(mShell), GDK_WINDOW_TYPE_HINT_UTILITY);
+  } else if (aInitData && aInitData->mIsAlert) {
+    LOG("    Is alert window\n");
+    gtk_window_set_type_hint(GTK_WINDOW(mShell),
+                             GDK_WINDOW_TYPE_HINT_NOTIFICATION);
+  } else if (mWindowType == WindowType::Dialog) {
+    mGtkWindowRoleName = "Dialog";
+
+    SetDefaultIcon();
+    gtk_window_set_type_hint(GTK_WINDOW(mShell), GDK_WINDOW_TYPE_HINT_DIALOG);
+    LOG("nsWindow::Create(): dialog");
+    if (parentnsWindow) {
+      GtkWindowSetTransientFor(GTK_WINDOW(mShell),
+                               GTK_WINDOW(parentnsWindow->GetGtkWidget()));
+      LOG("    set parent window [%p]\n", parentnsWindow);
+    }
+  } else if (mWindowType == WindowType::Popup) {
+    MOZ_ASSERT(aInitData);
+    mGtkWindowRoleName = "Popup";
+
+    LOG("nsWindow::Create() Popup");
+
+    if (mNoAutoHide) {
+      // ... but the window manager does not decorate this window,
+      // nor provide a separate taskbar icon.
+      if (mBorderStyle == BorderStyle::Default) {
+        gtk_window_set_decorated(GTK_WINDOW(mShell), FALSE);
+      } else {
+        bool decorate = bool(mBorderStyle & BorderStyle::Title);
+        gtk_window_set_decorated(GTK_WINDOW(mShell), decorate);
+        if (decorate) {
+          gtk_window_set_deletable(GTK_WINDOW(mShell),
+                                   bool(mBorderStyle & BorderStyle::Close));
+        }
+      }
+      gtk_window_set_skip_taskbar_hint(GTK_WINDOW(mShell), TRUE);
+      // Element focus is managed by the parent window so the
+      // WM_HINTS input field is set to False to tell the window
+      // manager not to set input focus to this window ...
+      gtk_window_set_accept_focus(GTK_WINDOW(mShell), FALSE);
+#ifdef MOZ_X11
+      // ... but when the window manager offers focus through
+      // WM_TAKE_FOCUS, focus is requested on the parent window.
+      if (GdkIsX11Display()) {
+        gtk_widget_realize(mShell);
+        gdk_window_add_filter(GetToplevelGdkWindow(), popup_take_focus_filter,
+                              nullptr);
+      }
+#endif
+    }
+
+    if (aInitData->mIsDragPopup) {
+      gtk_window_set_type_hint(GTK_WINDOW(mShell), GDK_WINDOW_TYPE_HINT_DND);
+      mIsDragPopup = true;
+      LOG("nsWindow::Create() Drag popup\n");
+    } else if (GdkIsX11Display()) {
+      // Set the window hints on X11 only. Wayland popups are configured
+      // at WaylandPopupConfigure().
+      GdkWindowTypeHint gtkTypeHint;
+      switch (mPopupType) {
+        case PopupType::Menu:
+          gtkTypeHint = GDK_WINDOW_TYPE_HINT_POPUP_MENU;
+          break;
+        case PopupType::Tooltip:
+          gtkTypeHint = GDK_WINDOW_TYPE_HINT_TOOLTIP;
+          break;
+        default:
+          gtkTypeHint = GDK_WINDOW_TYPE_HINT_UTILITY;
+          break;
+      }
+      gtk_window_set_type_hint(GTK_WINDOW(mShell), gtkTypeHint);
+      LOG("nsWindow::Create() popup type %s", GetPopupTypeName().get());
+    }
+    if (parentnsWindow) {
+      LOG("    set parent window [%p] %s", parentnsWindow,
+          parentnsWindow->mGtkWindowRoleName.get());
+      GtkWindow* parentWidget = GTK_WINDOW(parentnsWindow->GetGtkWidget());
+      GtkWindowSetTransientFor(GTK_WINDOW(mShell), parentWidget);
+
+      // If popup parent is modal, we need to make popup modal too.
+      if (mPopupType != PopupType::Tooltip &&
+          gtk_window_get_modal(parentWidget)) {
+        gtk_window_set_modal(GTK_WINDOW(mShell), true);
+      }
+    }
+
+    // We need realized mShell at NativeMoveResize().
+    gtk_widget_realize(mShell);
+
+    // With popup windows, we want to set their position.
+    // Place them immediately on X11 and save initial popup position
+    // on Wayland as we place Wayland popup on show.
+    if (GdkIsX11Display()) {
+      NativeMoveResize(/* move */ true, /* resize */ false);
+    } else if (AreBoundsSane()) {
+      GdkRectangle rect = DevicePixelsToGdkRectRoundOut(mBounds);
+      mPopupPosition = {rect.x, rect.y};
+    }
+  } else {  // must be WindowType::TopLevel
+    mGtkWindowRoleName = "Toplevel";
+    SetDefaultIcon();
+
+    LOG("nsWindow::Create() Toplevel\n");
+
+    // each toplevel window gets its own window group
+    GtkWindowGroup* group = gtk_window_group_new();
+    gtk_window_group_add_window(group, GTK_WINDOW(mShell));
+    g_object_unref(group);
+  }
+
+  if (mAlwaysOnTop) {
+    gtk_window_set_keep_above(GTK_WINDOW(mShell), TRUE);
+  }
+
+  // It is important that this happens before the realize() call below, so that
+  // we don't get bogus CSD margins on Wayland, see bug 1794577.
+  mUndecorated = IsAlwaysUndecoratedWindow();
+  if (mUndecorated) {
+    LOG("    Is undecorated Window\n");
+    gtk_window_set_titlebar(GTK_WINDOW(mShell), gtk_fixed_new());
+    gtk_window_set_decorated(GTK_WINDOW(mShell), false);
+  }
+
+  // Create a container to hold child windows and child GtkWidgets.
+  GtkWidget* container = moz_container_new();
+  mContainer = MOZ_CONTAINER(container);
+
+  // Prevent GtkWindow from painting a background to avoid flickering.
+  gtk_widget_set_app_paintable(
+      GTK_WIDGET(mContainer),
+      StaticPrefs::widget_transparent_windows_AtStartup());
+
+  gtk_widget_add_events(GTK_WIDGET(mContainer), kEvents);
+  gtk_widget_add_events(mShell, GDK_PROPERTY_CHANGE_MASK);
+  gtk_widget_set_app_paintable(
+      mShell, StaticPrefs::widget_transparent_windows_AtStartup());
+
+  if (mTransparencyBitmapForTitlebar) {
+    moz_container_force_default_visual(mContainer);
+  }
+
+  // If we draw to mContainer window then configure it now because
+  // gtk_container_add() realizes the child widget.
+  gtk_widget_set_has_window(container, true);
+  gtk_container_add(GTK_CONTAINER(mShell), container);
+
+  // alwaysontop windows are generally used for peripheral indicators,
+  // so we don't focus them by default.
+  if (mAlwaysOnTop) {
+    gtk_window_set_focus_on_map(GTK_WINDOW(mShell), FALSE);
+  }
+
+  gtk_widget_realize(container);
+
+  // make sure this is the focus widget in the container
+  gtk_widget_show(container);
+
+  if (!mAlwaysOnTop) {
+    gtk_widget_grab_focus(container);
+  }
+
+#ifdef MOZ_WAYLAND
+  if (mIsDragPopup && GdkIsWaylandDisplay()) {
+    LOG("  set commit to parent");
+    moz_container_wayland_set_commit_to_parent(mContainer);
+  }
+#endif
+
+  if (mWindowType == WindowType::TopLevel && gKioskMode) {
+    if (gKioskMonitor != -1) {
+      mKioskMonitor = Some(gKioskMonitor);
+      LOG("  set kiosk mode monitor %d", mKioskMonitor.value());
+    } else {
+      LOG("  set kiosk mode");
+    }
+    // Kiosk mode always use fullscreen.
+    MakeFullScreen(/* aFullScreen */ true);
+  }
+
+  if (mWindowType == WindowType::Popup) {
+    MOZ_ASSERT(aInitData);
+    // gdk does not automatically set the cursor for "temporary"
+    // windows, which are what gtk uses for popups.
+
+    // force SetCursor to actually set the cursor, even though our internal
+    // state indicates that we already have the standard cursor.
+    mUpdateCursor = true;
+    SetCursor(Cursor{eCursor_standard});
+  }
+
+  if (mIsChildWindow && parentnsWindow) {
+    GdkWindow* window = GetToplevelGdkWindow();
+    GdkWindow* parentWindow = parentnsWindow->GetToplevelGdkWindow();
+    LOG("  child GdkWindow %p set parent GdkWindow %p", window, parentWindow);
+    gdk_window_reparent(window, parentWindow,
+                        DevicePixelsToGdkCoordRoundDown(mBounds.x),
+                        DevicePixelsToGdkCoordRoundDown(mBounds.y));
+  }
+
+  // Also label mShell toplevel window,
+  // property_notify_event_cb callback also needs to find its way home
+  g_object_set_data(G_OBJECT(GetToplevelGdkWindow()), "nsWindow", this);
+  g_object_set_data(G_OBJECT(mContainer), "nsWindow", this);
+  g_object_set_data(G_OBJECT(mShell), "nsWindow", this);
+
+  // attach listeners for events
+  g_signal_connect(mShell, "configure_event", G_CALLBACK(configure_event_cb),
+                   nullptr);
+  g_signal_connect(mShell, "delete_event", G_CALLBACK(delete_event_cb),
+                   nullptr);
+  g_signal_connect(mShell, "window_state_event",
+                   G_CALLBACK(window_state_event_cb), nullptr);
+  g_signal_connect(mShell, "visibility-notify-event",
+                   G_CALLBACK(visibility_notify_event_cb), nullptr);
+  g_signal_connect(mShell, "check-resize", G_CALLBACK(check_resize_cb),
+                   nullptr);
+  g_signal_connect(mShell, "composited-changed",
+                   G_CALLBACK(widget_composited_changed_cb), nullptr);
+  g_signal_connect(mShell, "property-notify-event",
+                   G_CALLBACK(property_notify_event_cb), nullptr);
+
+  if (mWindowType == WindowType::TopLevel) {
+    g_signal_connect_after(mShell, "size_allocate",
+                           G_CALLBACK(toplevel_window_size_allocate_cb),
+                           nullptr);
+  }
+
+  GdkScreen* screen = gtk_widget_get_screen(mShell);
+  if (!g_signal_handler_find(screen, G_SIGNAL_MATCH_FUNC, 0, 0, nullptr,
+                             FuncToGpointer(screen_composited_changed_cb),
+                             nullptr)) {
+    g_signal_connect(screen, "composited-changed",
+                     G_CALLBACK(screen_composited_changed_cb), nullptr);
+  }
+
+  gtk_drag_dest_set((GtkWidget*)mShell, (GtkDestDefaults)0, nullptr, 0,
+                    (GdkDragAction)0);
+  g_signal_connect(mShell, "drag_motion", G_CALLBACK(drag_motion_event_cb),
+                   nullptr);
+  g_signal_connect(mShell, "drag_leave", G_CALLBACK(drag_leave_event_cb),
+                   nullptr);
+  g_signal_connect(mShell, "drag_drop", G_CALLBACK(drag_drop_event_cb),
+                   nullptr);
+  g_signal_connect(mShell, "drag_data_received",
+                   G_CALLBACK(drag_data_received_event_cb), nullptr);
+
+  GtkSettings* default_settings = gtk_settings_get_default();
+  g_signal_connect_after(default_settings, "notify::gtk-xft-dpi",
+                         G_CALLBACK(settings_xft_dpi_changed_cb), this);
+
+  // Widget signals
+  g_signal_connect(mContainer, "map", G_CALLBACK(widget_map_cb), nullptr);
+  g_signal_connect(mContainer, "unmap", G_CALLBACK(widget_unmap_cb), nullptr);
+  g_signal_connect_after(mContainer, "size_allocate",
+                         G_CALLBACK(size_allocate_cb), nullptr);
+  g_signal_connect(mContainer, "hierarchy-changed",
+                   G_CALLBACK(hierarchy_changed_cb), nullptr);
+  g_signal_connect(mContainer, "notify::scale-factor",
+                   G_CALLBACK(scale_changed_cb), nullptr);
+  // Initialize mHasMappedToplevel.
+  hierarchy_changed_cb(GTK_WIDGET(mContainer), nullptr);
+  // Expose, focus, key, and drag events are sent even to GTK_NO_WINDOW
+  // widgets.
+  g_signal_connect(G_OBJECT(mContainer), "draw", G_CALLBACK(expose_event_cb),
+                   nullptr);
+  g_signal_connect(mContainer, "focus_in_event", G_CALLBACK(focus_in_event_cb),
+                   nullptr);
+  g_signal_connect(mContainer, "focus_out_event",
+                   G_CALLBACK(focus_out_event_cb), nullptr);
+  g_signal_connect(mContainer, "key_press_event",
+                   G_CALLBACK(key_press_event_cb), nullptr);
+  g_signal_connect(mContainer, "key_release_event",
+                   G_CALLBACK(key_release_event_cb), nullptr);
+
+#ifdef MOZ_X11
+  if (GdkIsX11Display()) {
+    gtk_widget_set_double_buffered(GTK_WIDGET(mContainer), FALSE);
+  }
+#endif
+#ifdef MOZ_WAYLAND
+  // Initialize the window specific VsyncSource early in order to avoid races
+  // with BrowserParent::UpdateVsyncParentVsyncDispatcher().
+  // Only use for toplevel windows for now, see bug 1619246.
+  if (GdkIsWaylandDisplay() &&
+      StaticPrefs::widget_wayland_vsync_enabled_AtStartup() &&
+      IsTopLevelWindowType()) {
+    mWaylandVsyncSource = new WaylandVsyncSource(this);
+    mWaylandVsyncDispatcher = new VsyncDispatcher(mWaylandVsyncSource);
+    LOG_VSYNC("  created WaylandVsyncSource");
+  }
+#endif
+
+  // We create input contexts for all containers, except for
+  // toplevel popup windows
+  if (mWindowType != WindowType::Popup) {
+    mIMContext = new IMContextWrapper(this);
+  }
+
+  // These events are sent to the owning widget of the relevant window
+  // and propagate up to the first widget that handles the events, so we
+  // need only connect on mShell, if it exists, to catch events on its
+  // window and windows of mContainer.
+  g_signal_connect(mContainer, "enter-notify-event",
+                   G_CALLBACK(enter_notify_event_cb), nullptr);
+  g_signal_connect(mContainer, "leave-notify-event",
+                   G_CALLBACK(leave_notify_event_cb), nullptr);
+  g_signal_connect(mContainer, "motion-notify-event",
+                   G_CALLBACK(motion_notify_event_cb), nullptr);
+  g_signal_connect(mContainer, "button-press-event",
+                   G_CALLBACK(button_press_event_cb), nullptr);
+  g_signal_connect(mContainer, "button-release-event",
+                   G_CALLBACK(button_release_event_cb), nullptr);
+  g_signal_connect(mContainer, "scroll-event", G_CALLBACK(scroll_event_cb),
+                   nullptr);
+  if (gtk_check_version(3, 18, 0) == nullptr) {
+    g_signal_connect(mContainer, "event", G_CALLBACK(generic_event_cb),
+                     nullptr);
+  }
+  g_signal_connect(mContainer, "touch-event", G_CALLBACK(touch_event_cb),
+                   nullptr);
+
+  LOG("  nsWindow type %d %s\n", int(mWindowType),
+      mIsPIPWindow ? "PIP window" : "");
+  LOG("  mShell %p (window %p) mContainer %p mGdkWindow %p XID 0x%lx\n", mShell,
+      GetToplevelGdkWindow(), mContainer, mGdkWindow, GetX11Window());
+
+  // Set default application name when it's empty.
+  if (mGtkWindowAppName.IsEmpty()) {
+    mGtkWindowAppName = gAppData->name;
+  }
+
+  mCreated = true;
+  return NS_OK;
+}
+
+void nsWindow::RefreshWindowClass(void) {
+  GdkWindow* gdkWindow = GetToplevelGdkWindow();
+  if (!gdkWindow) {
+    return;
+  }
+
+  if (!mGtkWindowRoleName.IsEmpty()) {
+    gdk_window_set_role(gdkWindow, mGtkWindowRoleName.get());
+  }
+
+#ifdef MOZ_X11
+  if (GdkIsX11Display()) {
+    XClassHint* class_hint = XAllocClassHint();
+    if (!class_hint) {
+      return;
+    }
+
+    const char* res_name =
+        !mGtkWindowAppName.IsEmpty() ? mGtkWindowAppName.get() : gAppData->name;
+
+    const char* res_class = !mGtkWindowAppClass.IsEmpty()
+                                ? mGtkWindowAppClass.get()
+                                : gdk_get_program_class();
+
+    if (!res_name || !res_class) {
+      XFree(class_hint);
+      return;
+    }
+
+    class_hint->res_name = const_cast<char*>(res_name);
+    class_hint->res_class = const_cast<char*>(res_class);
+
+    // Can't use gtk_window_set_wmclass() for this; it prints
+    // a warning & refuses to make the change.
+    GdkDisplay* display = gdk_display_get_default();
+    XSetClassHint(GDK_DISPLAY_XDISPLAY(display),
+                  gdk_x11_window_get_xid(gdkWindow), class_hint);
+    XFree(class_hint);
+  }
+#endif /* MOZ_X11 */
+
+#ifdef MOZ_WAYLAND
+  static auto sGdkWaylandWindowSetApplicationId =
+      (void (*)(GdkWindow*, const char*))dlsym(
+          RTLD_DEFAULT, "gdk_wayland_window_set_application_id");
+
+  if (GdkIsWaylandDisplay() && sGdkWaylandWindowSetApplicationId &&
+      !mGtkWindowAppClass.IsEmpty()) {
+    sGdkWaylandWindowSetApplicationId(gdkWindow, mGtkWindowAppClass.get());
+  }
+#endif /* MOZ_WAYLAND */
+}
+
+void nsWindow::SetWindowClass(const nsAString& xulWinType,
+                              const nsAString& xulWinClass,
+                              const nsAString& xulWinName) {
+  if (!mShell) {
+    return;
+  }
+
+  // If window type attribute is set, parse it into name and role
+  if (!xulWinType.IsEmpty()) {
+    char* res_name = ToNewCString(xulWinType, mozilla::fallible);
+    const char* role = nullptr;
+
+    if (res_name) {
+      // Parse res_name into a name and role. Characters other than
+      // [A-Za-z0-9_-] are converted to '_'. Anything after the first
+      // colon is assigned to role; if there's no colon, assign the
+      // whole thing to both role and res_name.
+      for (char* c = res_name; *c; c++) {
+        if (':' == *c) {
+          *c = 0;
+          role = c + 1;
+        } else if (!isascii(*c) ||
+                   (!isalnum(*c) && ('_' != *c) && ('-' != *c))) {
+          *c = '_';
+        }
+      }
+      res_name[0] = (char)toupper(res_name[0]);
+      if (!role) role = res_name;
+
+      mGtkWindowAppName = res_name;
+      mGtkWindowRoleName = role;
+      free(res_name);
+    }
+  }
+
+  // If window class attribute is set, store it as app class
+  // If this attribute is not set, reset app class to default
+  if (!xulWinClass.IsEmpty()) {
+    CopyUTF16toUTF8(xulWinClass, mGtkWindowAppClass);
+  } else {
+    mGtkWindowAppClass = nullptr;
+  }
+
+  // If window class attribute is set, store it as app name
+  // If both name and type are not set, reset app name to default
+  if (!xulWinName.IsEmpty()) {
+    CopyUTF16toUTF8(xulWinName, mGtkWindowAppName);
+  } else if (xulWinType.IsEmpty()) {
+    mGtkWindowAppClass = nullptr;
+  }
+
+  RefreshWindowClass();
+}
+
+nsAutoCString nsWindow::GetDebugTag() const {
+  nsAutoCString tag;
+  tag.AppendPrintf("[%p]", this);
+  return tag;
+}
+
+void nsWindow::NativeMoveResize(bool aMoved, bool aResized) {
+  GdkPoint topLeft = [&] {
+    auto target = mBounds.TopLeft();
+    // gtk_window_move will undo the csd offset, but nothing else, so only add
+    // the client offset if drawing to the csd titlebar.
+    if (DrawsToCSDTitlebar()) {
+      target += mClientOffset;
+    }
+    return DevicePixelsToGdkPointRoundDown(target);
+  }();
+  GdkRectangle size = DevicePixelsToGdkSizeRoundUp(mLastSizeRequest);
+
+  LOG("nsWindow::NativeMoveResize move %d resize %d to %d,%d -> %d x %d\n",
+      aMoved, aResized, topLeft.x, topLeft.y, size.width, size.height);
+
+  if (aResized && !AreBoundsSane()) {
+    LOG("  bounds are insane, hidding the window");
+    // We have been resized but to incorrect size.
+    // If someone has set this so that the needs show flag is false
+    // and it needs to be hidden, update the flag and hide the
+    // window.  This flag will be cleared the next time someone
+    // hides the window or shows it.  It also prevents us from
+    // calling NativeShow(false) excessively on the window which
+    // causes unneeded X traffic.
+    if (!mNeedsShow && mIsShown) {
+      mNeedsShow = true;
+      NativeShow(false);
+    }
+    if (aMoved) {
+      LOG("  moving to %d x %d", topLeft.x, topLeft.y);
+      gtk_window_move(GTK_WINDOW(mShell), topLeft.x, topLeft.y);
+    }
+    return;
+  }
+
+  // Set position to hidden window on X11 may fail, so save the position
+  // and move it when it's shown.
+  if (aMoved && GdkIsX11Display() && IsPopup() &&
+      !gtk_widget_get_visible(GTK_WIDGET(mShell))) {
+    LOG("  store position of hidden popup window");
+    mHiddenPopupPositioned = true;
+    mPopupPosition = {topLeft.x, topLeft.y};
+  }
+
+  if (IsWaylandPopup()) {
+    NativeMoveResizeWaylandPopup(aMoved, aResized);
+  } else {
+    // x and y give the position of the window manager frame top-left.
+    if (aMoved) {
+      gtk_window_move(GTK_WINDOW(mShell), topLeft.x, topLeft.y);
+    }
+    if (aResized) {
+      gtk_window_resize(GTK_WINDOW(mShell), size.width, size.height);
+      if (mIsDragPopup) {
+        // DND window is placed inside container so we need to make hard size
+        // request to ensure parent container is resized too.
+        gtk_widget_set_size_request(GTK_WIDGET(mShell), size.width,
+                                    size.height);
+      }
+    }
+  }
+
+  if (aResized) {
+    // Recompute the input region, in case the window grew or shrunk.
+    SetInputRegion(mInputRegion);
+  }
+
+  // Does it need to be shown because bounds were previously insane?
+  if (mNeedsShow && mIsShown && aResized) {
+    NativeShow(true);
+  }
+}
+
+// We pause compositor to avoid rendering of obsoleted remote content which
+// produces flickering.
+// Re-enable compositor again when remote content is updated or
+// timeout happens.
+
+// Define maximal compositor pause when it's paused to avoid flickering,
+// in milliseconds.
+#define COMPOSITOR_PAUSE_TIMEOUT (1000)
+
+void nsWindow::PauseCompositorFlickering() {
+  bool pauseCompositor = IsTopLevelWindowType() &&
+                         mCompositorState == COMPOSITOR_ENABLED &&
+                         mCompositorWidgetDelegate && !mIsDestroyed;
+  if (!pauseCompositor) {
+    return;
+  }
+
+  LOG("nsWindow::PauseCompositorFlickering()");
+
+  MozClearHandleID(mCompositorPauseTimeoutID, g_source_remove);
+
+  CompositorBridgeChild* remoteRenderer = GetRemoteRenderer();
+  if (remoteRenderer) {
+    remoteRenderer->SendPause();
+    mCompositorState = COMPOSITOR_PAUSED_FLICKERING;
+    mCompositorPauseTimeoutID = (int)g_timeout_add(
+        COMPOSITOR_PAUSE_TIMEOUT,
+        [](void* data) -> gint {
+          nsWindow* window = static_cast<nsWindow*>(data);
+          if (!window->IsDestroyed()) {
+            window->ResumeCompositorFlickering();
+          }
+          return true;
+        },
+        this);
+  }
+}
+
+bool nsWindow::IsWaitingForCompositorResume() {
+  return mCompositorState == COMPOSITOR_PAUSED_FLICKERING;
+}
+
+void nsWindow::ResumeCompositorFlickering() {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+
+  LOG("nsWindow::ResumeCompositorFlickering()\n");
+
+  if (mIsDestroyed || !IsWaitingForCompositorResume()) {
+    LOG("  early quit\n");
+    return;
+  }
+
+  MozClearHandleID(mCompositorPauseTimeoutID, g_source_remove);
+
+  // mCompositorWidgetDelegate can be deleted during timeout.
+  // In such case just flip compositor back to enabled and let
+  // SetCompositorWidgetDelegate() or Map event resume it.
+  if (!mCompositorWidgetDelegate) {
+    mCompositorState = COMPOSITOR_ENABLED;
+    return;
+  }
+
+  ResumeCompositorImpl();
+}
+
+void nsWindow::ResumeCompositorFromCompositorThread() {
+  nsCOMPtr<nsIRunnable> event =
+      NewRunnableMethod("nsWindow::ResumeCompositorFlickering", this,
+                        &nsWindow::ResumeCompositorFlickering);
+  NS_DispatchToMainThread(event.forget());
+}
+
+void nsWindow::ResumeCompositorImpl() {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+
+  LOG("nsWindow::ResumeCompositorImpl()\n");
+
+  MOZ_DIAGNOSTIC_ASSERT(mCompositorWidgetDelegate);
+
+  // DisableRendering() clears stored X11Window so we're sure EnableRendering()
+  // really updates it.
+  mCompositorWidgetDelegate->DisableRendering();
+  mCompositorWidgetDelegate->EnableRendering(GetX11Window(), GetShapedState());
+
+  // As WaylandStartVsync needs mCompositorWidgetDelegate this is the right
+  // time to start it.
+  WaylandStartVsync();
+
+  CompositorBridgeChild* remoteRenderer = GetRemoteRenderer();
+  MOZ_RELEASE_ASSERT(remoteRenderer);
+  remoteRenderer->SendResume();
+  remoteRenderer->SendForcePresent(wr::RenderReasons::WIDGET);
+  mCompositorState = COMPOSITOR_ENABLED;
+}
+
+void nsWindow::WaylandStartVsync() {
+#ifdef MOZ_WAYLAND
+  if (!mWaylandVsyncSource) {
+    return;
+  }
+
+  LOG_VSYNC("nsWindow::WaylandStartVsync");
+
+  MOZ_DIAGNOSTIC_ASSERT(mCompositorWidgetDelegate);
+  if (mCompositorWidgetDelegate->AsGtkCompositorWidget() &&
+      mCompositorWidgetDelegate->AsGtkCompositorWidget()
+          ->GetNativeLayerRoot()) {
+    LOG_VSYNC("  use source NativeLayerRootWayland");
+    mWaylandVsyncSource->MaybeUpdateSource(
+        mCompositorWidgetDelegate->AsGtkCompositorWidget()
+            ->GetNativeLayerRoot()
+            ->AsNativeLayerRootWayland());
+  } else {
+    LOG_VSYNC("  use source mContainer");
+    mWaylandVsyncSource->MaybeUpdateSource(mContainer);
+  }
+
+  mWaylandVsyncSource->EnableMonitor();
+#endif
+}
+
+void nsWindow::WaylandStopVsync() {
+#ifdef MOZ_WAYLAND
+  if (!mWaylandVsyncSource) {
+    return;
+  }
+
+  LOG_VSYNC("nsWindow::WaylandStopVsync");
+
+  // The widget is going to be hidden, so clear the surface of our
+  // vsync source.
+  mWaylandVsyncSource->DisableMonitor();
+  mWaylandVsyncSource->MaybeUpdateSource(nullptr);
+#endif
+}
+
+void nsWindow::NativeShow(bool aAction) {
+  if (aAction) {
+    // unset our flag now that our window has been shown
+    mNeedsShow = true;
+    auto removeShow = MakeScopeExit([&] { mNeedsShow = false; });
+
+    LOG("nsWindow::NativeShow show\n");
+
+    if (IsWaylandPopup()) {
+      mPopupClosed = false;
+      if (WaylandPopupConfigure()) {
+        AddWindowToPopupHierarchy();
+        UpdateWaylandPopupHierarchy();
+        if (mPopupClosed) {
+          return;
+        }
+      }
+    }
+    // Set up usertime/startupID metadata for the created window.
+    // On X11 we use gtk_window_set_startup_id() so we need to call it
+    // before show.
+    if (GdkIsX11Display()) {
+      SetUserTimeAndStartupTokenForActivatedWindow();
+    }
+    if (GdkIsWaylandDisplay()) {
+      if (IsWaylandPopup()) {
+        ShowWaylandPopupWindow();
+      } else {
+        ShowWaylandToplevelWindow();
+      }
+    } else {
+      LOG("  calling gtk_widget_show(mShell)\n");
+      gtk_widget_show(mShell);
+    }
+    if (GdkIsWaylandDisplay()) {
+      SetUserTimeAndStartupTokenForActivatedWindow();
+#ifdef MOZ_WAYLAND
+      auto token = std::move(mWindowActivationTokenFromEnv);
+      if (!token.IsEmpty()) {
+        FocusWaylandWindow(token.get());
+      }
+#endif
+    }
+    if (mHiddenPopupPositioned && IsPopup()) {
+      LOG("  re-position hidden popup window");
+      gtk_window_move(GTK_WINDOW(mShell), mPopupPosition.x, mPopupPosition.y);
+      mHiddenPopupPositioned = false;
+    }
+  } else {
+    LOG("nsWindow::NativeShow hide\n");
+    if (GdkIsWaylandDisplay()) {
+      if (IsWaylandPopup()) {
+        // We can't close tracked popups directly as they may have visible
+        // child popups. Just mark is as closed and let
+        // UpdateWaylandPopupHierarchy() do the job.
+        if (IsInPopupHierarchy()) {
+          WaylandPopupMarkAsClosed();
+          UpdateWaylandPopupHierarchy();
+        } else {
+          // Close untracked popups directly.
+          HideWaylandPopupWindow(/* aTemporaryHide */ false,
+                                 /* aRemoveFromPopupList */ true);
+        }
+      } else {
+        HideWaylandToplevelWindow();
+      }
+    } else {
+      // Workaround window freezes on GTK versions before 3.21.2 by
+      // ensuring that configure events get dispatched to windows before
+      // they are unmapped. See bug 1225044.
+      if (gtk_check_version(3, 21, 2) != nullptr && mPendingConfigures > 0) {
+        GtkAllocation allocation;
+        gtk_widget_get_allocation(GTK_WIDGET(mShell), &allocation);
+
+        GdkEventConfigure event;
+        PodZero(&event);
+        event.type = GDK_CONFIGURE;
+        event.window = mGdkWindow;
+        event.send_event = TRUE;
+        event.x = allocation.x;
+        event.y = allocation.y;
+        event.width = allocation.width;
+        event.height = allocation.height;
+
+        auto* shellClass = GTK_WIDGET_GET_CLASS(mShell);
+        for (unsigned int i = 0; i < mPendingConfigures; i++) {
+          Unused << shellClass->configure_event(mShell, &event);
+        }
+        mPendingConfigures = 0;
+      }
+      gtk_widget_hide(mShell);
+
+      ClearTransparencyBitmap();  // Release some resources
+    }
+  }
+}
+
+void nsWindow::SetHasMappedToplevel(bool aState) {
+  LOG("nsWindow::SetHasMappedToplevel(%d)", aState);
+  if (aState == mHasMappedToplevel) {
+    return;
+  }
+  // Even when aState == mHasMappedToplevel (as when this method is called
+  // from Show()), child windows need to have their state checked, so don't
+  // return early.
+  mHasMappedToplevel = aState;
+  if (aState && mNeedsToRetryCapturingMouse) {
+    CaptureRollupEvents(true);
+    MOZ_ASSERT(!mNeedsToRetryCapturingMouse);
+  }
+}
+
+LayoutDeviceIntSize nsWindow::GetSafeWindowSize(LayoutDeviceIntSize aSize) {
+  // The X protocol uses CARD32 for window sizes, but the server (1.11.3)
+  // reads it as CARD16.  Sizes of pixmaps, used for drawing, are (unsigned)
+  // CARD16 in the protocol, but the server's ProcCreatePixmap returns
+  // BadAlloc if dimensions cannot be represented by signed shorts.
+  // Because we are creating Cairo surfaces to represent window buffers,
+  // we also must ensure that the window can fit in a Cairo surface.
+  LayoutDeviceIntSize result = aSize;
+  int32_t maxSize = 32767;
+  if (mWindowRenderer && mWindowRenderer->AsKnowsCompositor()) {
+    maxSize = std::min(
+        maxSize, mWindowRenderer->AsKnowsCompositor()->GetMaxTextureSize());
+  }
+  if (result.width > maxSize) {
+    result.width = maxSize;
+  }
+  if (result.height > maxSize) {
+    result.height = maxSize;
+  }
+  return result;
+}
+
+void nsWindow::SetTransparencyMode(TransparencyMode aMode) {
+  bool isTransparent = aMode == TransparencyMode::Transparent;
+
+  if (mIsTransparent == isTransparent) {
+    return;
+  }
+
+  if (mWindowType != WindowType::Popup) {
+    // https://bugzilla.mozilla.org/show_bug.cgi?id=1344839 reported
+    // problems cleaning the layer manager for toplevel windows.
+    // Ignore the request so as to workaround that.
+    // mIsTransparent is set in Create() if transparency may be required.
+    if (isTransparent) {
+      NS_WARNING("Transparent mode not supported on non-popup windows.");
+    }
+    return;
+  }
+
+  if (!isTransparent) {
+    ClearTransparencyBitmap();
+  }  // else the new default alpha values are "all 1", so we don't
+  // need to change anything yet
+
+  mIsTransparent = isTransparent;
+
+  if (!mHasAlphaVisual) {
+    // The choice of layer manager depends on
+    // GtkCompositorWidgetInitData::Shaped(), which will need to change, so
+    // clean out the old layer manager.
+    DestroyLayerManager();
+  }
+}
+
+TransparencyMode nsWindow::GetTransparencyMode() {
+  return mIsTransparent ? TransparencyMode::Transparent
+                        : TransparencyMode::Opaque;
+}
+
+gint nsWindow::GetInputRegionMarginInGdkCoords() {
+  return DevicePixelsToGdkCoordRoundDown(mInputRegion.mMargin);
+}
+
+void nsWindow::SetInputRegion(const InputRegion& aInputRegion) {
+  mInputRegion = aInputRegion;
+
+  GdkWindow* window = GetToplevelGdkWindow();
+  if (!window) {
+    return;
+  }
+
+  LOG("nsWindow::SetInputRegion(%d, %d)", aInputRegion.mFullyTransparent,
+      int(aInputRegion.mMargin));
+
+  cairo_rectangle_int_t rect = {0, 0, 0, 0};
+  cairo_region_t* region = nullptr;
+  auto releaseRegion = MakeScopeExit([&] {
+    if (region) {
+      cairo_region_destroy(region);
+    }
+  });
+
+  if (aInputRegion.mFullyTransparent) {
+    region = cairo_region_create_rectangle(&rect);
+  } else if (aInputRegion.mMargin != 0) {
+    LayoutDeviceIntRect inputRegion(LayoutDeviceIntPoint(), mLastSizeRequest);
+    inputRegion.Deflate(aInputRegion.mMargin);
+    GdkRectangle gdkRect = DevicePixelsToGdkRectRoundOut(inputRegion);
+    rect = {gdkRect.x, gdkRect.y, gdkRect.width, gdkRect.height};
+    region = cairo_region_create_rectangle(&rect);
+  }
+
+  gdk_window_input_shape_combine_region(window, region, 0, 0);
+
+  // On Wayland gdk_window_input_shape_combine_region() call is cached and
+  // applied to underlying wl_surface when GdkWindow is repainted.
+  // Force repaint of GdkWindow to apply the change immediately.
+  if (GdkIsWaylandDisplay()) {
+    gdk_window_invalidate_rect(window, nullptr, false);
+  }
+}
+
+// For setting the draggable titlebar region from CSS
+// with -moz-window-dragging: drag.
+void nsWindow::UpdateWindowDraggingRegion(
+    const LayoutDeviceIntRegion& aRegion) {
+  if (mDraggableRegion != aRegion) {
+    mDraggableRegion = aRegion;
+  }
+}
+
+LayoutDeviceIntCoord nsWindow::GetTitlebarRadius() {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+  int32_t cssCoord = LookAndFeel::GetInt(LookAndFeel::IntID::TitlebarRadius);
+  return GdkCoordToDevicePixels(cssCoord);
+}
+
+// See subtract_corners_from_region() at gtk/gtkwindow.c
+// We need to subtract corners from toplevel window opaque region
+// to draw transparent corners of default Gtk titlebar.
+// Both implementations (cairo_region_t and wl_region) needs to be synced.
+static void SubtractTitlebarCorners(cairo_region_t* aRegion, int aX, int aY,
+                                    int aWindowWidth, int aWindowHeight,
+                                    int aTitlebarRadius) {
+  if (!aTitlebarRadius) {
+    return;
+  }
+  cairo_rectangle_int_t rect = {aX, aY, aTitlebarRadius, aTitlebarRadius};
+  cairo_region_subtract_rectangle(aRegion, &rect);
+  rect = {
+      aX + aWindowWidth - aTitlebarRadius,
+      aY,
+      aTitlebarRadius,
+      aTitlebarRadius,
+  };
+  cairo_region_subtract_rectangle(aRegion, &rect);
+  rect = {
+      aX,
+      aY + aWindowHeight - aTitlebarRadius,
+      aTitlebarRadius,
+      aTitlebarRadius,
+  };
+  cairo_region_subtract_rectangle(aRegion, &rect);
+  rect = {
+      aX + aWindowWidth - aTitlebarRadius,
+      aY + aWindowHeight - aTitlebarRadius,
+      aTitlebarRadius,
+      aTitlebarRadius,
+  };
+  cairo_region_subtract_rectangle(aRegion, &rect);
+}
+
+void nsWindow::UpdateTopLevelOpaqueRegion() {
+  if (!mCompositedScreen) {
+    return;
+  }
+
+  GdkWindow* window = GetToplevelGdkWindow();
+  if (!window) {
+    return;
+  }
+  MOZ_ASSERT(gdk_window_get_window_type(window) == GDK_WINDOW_TOPLEVEL);
+
+  int x = 0;
+  int y = 0;
+
+  gdk_window_get_position(mGdkWindow, &x, &y);
+
+  int width = DevicePixelsToGdkCoordRoundDown(mBounds.width);
+  int height = DevicePixelsToGdkCoordRoundDown(mBounds.height);
+
+  cairo_region_t* region = cairo_region_create();
+  cairo_rectangle_int_t rect = {x, y, width, height};
+  cairo_region_union_rectangle(region, &rect);
+
+  // TODO: We actually could get a proper opaque region from layout, see
+  // nsIWidget::UpdateOpaqueRegion. This could simplify titlebar drawing.
+  int radius = DoDrawTilebarCorners() ? int(GetTitlebarRadius()) : 0;
+  SubtractTitlebarCorners(region, x, y, width, height, radius);
+
+  gdk_window_set_opaque_region(window, region);
+
+  cairo_region_destroy(region);
+
+#ifdef MOZ_WAYLAND
+  if (GdkIsWaylandDisplay()) {
+    moz_container_wayland_update_opaque_region(mContainer, radius);
+  }
+#endif
+
+  SetTitlebarRect();
+}
+
+bool nsWindow::IsChromeWindowTitlebar() {
+  return mDrawInTitlebar && !mIsPIPWindow &&
+         mWindowType == WindowType::TopLevel;
+}
+
+bool nsWindow::DoDrawTilebarCorners() {
+  return IsChromeWindowTitlebar() && mSizeMode == nsSizeMode_Normal &&
+         !mIsTiled;
+}
+
+void nsWindow::ResizeTransparencyBitmap() {
+  if (!mTransparencyBitmap) {
+    return;
+  }
+
+  if (mBounds.width == mTransparencyBitmapWidth &&
+      mBounds.height == mTransparencyBitmapHeight) {
+    return;
+  }
+
+  int32_t newRowBytes = GetBitmapStride(mBounds.width);
+  int32_t newSize = newRowBytes * mBounds.height;
+  auto* newBits = new gchar[newSize];
+  // fill new mask with "transparent", first
+  memset(newBits, 0, newSize);
+
+  // Now copy the intersection of the old and new areas into the new mask
+  int32_t copyWidth = std::min(mBounds.width, mTransparencyBitmapWidth);
+  int32_t copyHeight = std::min(mBounds.height, mTransparencyBitmapHeight);
+  int32_t oldRowBytes = GetBitmapStride(mTransparencyBitmapWidth);
+  int32_t copyBytes = GetBitmapStride(copyWidth);
+
+  int32_t i;
+  gchar* fromPtr = mTransparencyBitmap;
+  gchar* toPtr = newBits;
+  for (i = 0; i < copyHeight; i++) {
+    memcpy(toPtr, fromPtr, copyBytes);
+    fromPtr += oldRowBytes;
+    toPtr += newRowBytes;
+  }
+
+  delete[] mTransparencyBitmap;
+  mTransparencyBitmap = newBits;
+  mTransparencyBitmapWidth = mBounds.width;
+  mTransparencyBitmapHeight = mBounds.height;
+}
+
+static bool ChangedMaskBits(gchar* aMaskBits, int32_t aMaskWidth,
+                            int32_t aMaskHeight, const nsIntRect& aRect,
+                            uint8_t* aAlphas, int32_t aStride) {
+  int32_t x, y, xMax = aRect.XMost(), yMax = aRect.YMost();
+  int32_t maskBytesPerRow = GetBitmapStride(aMaskWidth);
+  for (y = aRect.y; y < yMax; y++) {
+    gchar* maskBytes = aMaskBits + y * maskBytesPerRow;
+    uint8_t* alphas = aAlphas;
+    for (x = aRect.x; x < xMax; x++) {
+      bool newBit = *alphas > 0x7f;
+      alphas++;
+
+      gchar maskByte = maskBytes[x >> 3];
+      bool maskBit = (maskByte & (1 << (x & 7))) != 0;
+
+      if (maskBit != newBit) {
+        return true;
+      }
+    }
+    aAlphas += aStride;
+  }
+
+  return false;
+}
+
+static void UpdateMaskBits(gchar* aMaskBits, int32_t aMaskWidth,
+                           int32_t aMaskHeight, const nsIntRect& aRect,
+                           uint8_t* aAlphas, int32_t aStride) {
+  int32_t x, y, xMax = aRect.XMost(), yMax = aRect.YMost();
+  int32_t maskBytesPerRow = GetBitmapStride(aMaskWidth);
+  for (y = aRect.y; y < yMax; y++) {
+    gchar* maskBytes = aMaskBits + y * maskBytesPerRow;
+    uint8_t* alphas = aAlphas;
+    for (x = aRect.x; x < xMax; x++) {
+      bool newBit = *alphas > 0x7f;
+      alphas++;
+
+      gchar mask = 1 << (x & 7);
+      gchar maskByte = maskBytes[x >> 3];
+      // Note: '-newBit' turns 0 into 00...00 and 1 into 11...11
+      maskBytes[x >> 3] = (maskByte & ~mask) | (-newBit & mask);
+    }
+    aAlphas += aStride;
+  }
+}
+
+void nsWindow::ApplyTransparencyBitmap() {
+#ifdef MOZ_X11
+  // We use X11 calls where possible, because GDK handles expose events
+  // for shaped windows in a way that's incompatible with us (Bug 635903).
+  // It doesn't occur when the shapes are set through X.
+  Display* xDisplay = GDK_WINDOW_XDISPLAY(mGdkWindow);
+  Window xDrawable = GDK_WINDOW_XID(mGdkWindow);
+  Pixmap maskPixmap = XCreateBitmapFromData(
+      xDisplay, xDrawable, mTransparencyBitmap, mTransparencyBitmapWidth,
+      mTransparencyBitmapHeight);
+  XShapeCombineMask(xDisplay, xDrawable, ShapeBounding, 0, 0, maskPixmap,
+                    ShapeSet);
+  XFreePixmap(xDisplay, maskPixmap);
+#endif  // MOZ_X11
+}
+
+void nsWindow::ClearTransparencyBitmap() {
+  if (!mTransparencyBitmap) {
+    return;
+  }
+
+  delete[] mTransparencyBitmap;
+  mTransparencyBitmap = nullptr;
+  mTransparencyBitmapWidth = 0;
+  mTransparencyBitmapHeight = 0;
+
+  if (!mShell) {
+    return;
+  }
+
+#ifdef MOZ_X11
+  if (MOZ_UNLIKELY(!mGdkWindow)) {
+    return;
+  }
+
+  Display* xDisplay = GDK_WINDOW_XDISPLAY(mGdkWindow);
+  Window xWindow = gdk_x11_window_get_xid(mGdkWindow);
+
+  XShapeCombineMask(xDisplay, xWindow, ShapeBounding, 0, 0, X11None, ShapeSet);
+#endif
+}
+
+nsresult nsWindow::UpdateTranslucentWindowAlphaInternal(const nsIntRect& aRect,
+                                                        uint8_t* aAlphas,
+                                                        int32_t aStride) {
+  NS_ASSERTION(mIsTransparent, "Window is not transparent");
+  NS_ASSERTION(!mTransparencyBitmapForTitlebar,
+               "Transparency bitmap is already used for titlebar rendering");
+
+  if (mTransparencyBitmap == nullptr) {
+    int32_t size = GetBitmapStride(mBounds.width) * mBounds.height;
+    mTransparencyBitmap = new gchar[size];
+    memset(mTransparencyBitmap, 255, size);
+    mTransparencyBitmapWidth = mBounds.width;
+    mTransparencyBitmapHeight = mBounds.height;
+  } else {
+    ResizeTransparencyBitmap();
+  }
+
+  nsIntRect rect;
+  rect.IntersectRect(aRect, nsIntRect(0, 0, mBounds.width, mBounds.height));
+
+  if (!ChangedMaskBits(mTransparencyBitmap, mBounds.width, mBounds.height, rect,
+                       aAlphas, aStride)) {
+    // skip the expensive stuff if the mask bits haven't changed; hopefully
+    // this is the common case
+    return NS_OK;
+  }
+
+  UpdateMaskBits(mTransparencyBitmap, mBounds.width, mBounds.height, rect,
+                 aAlphas, aStride);
+
+  if (!mNeedsShow) {
+    ApplyTransparencyBitmap();
+  }
+  return NS_OK;
+}
+
+#define TITLEBAR_HEIGHT 10
+
+void nsWindow::SetTitlebarRect() {
+  MutexAutoLock lock(mTitlebarRectMutex);
+
+  if (!mGdkWindow || !DoDrawTilebarCorners()) {
+    mTitlebarRect = LayoutDeviceIntRect();
+    return;
+  }
+  mTitlebarRect = LayoutDeviceIntRect(0, 0, mBounds.width,
+                                      GdkCeiledScaleFactor() * TITLEBAR_HEIGHT);
+}
+
+LayoutDeviceIntRect nsWindow::GetTitlebarRect() {
+  MutexAutoLock lock(mTitlebarRectMutex);
+  return mTitlebarRect;
+}
+
+void nsWindow::UpdateTitlebarTransparencyBitmap() {
+  NS_ASSERTION(mTransparencyBitmapForTitlebar,
+               "Transparency bitmap is already used to draw window shape");
+
+  if (!mGdkWindow || !mDrawInTitlebar ||
+      (mBounds.width == mTransparencyBitmapWidth &&
+       mBounds.height == mTransparencyBitmapHeight)) {
+    return;
+  }
+
+  bool maskCreate =
+      !mTransparencyBitmap || mBounds.width > mTransparencyBitmapWidth;
+
+  bool maskUpdate =
+      !mTransparencyBitmap || mBounds.width != mTransparencyBitmapWidth;
+
+  LayoutDeviceIntCoord radius = GetTitlebarRadius();
+  if (maskCreate) {
+    delete[] mTransparencyBitmap;
+    int32_t size = GetBitmapStride(mBounds.width) * radius;
+    mTransparencyBitmap = new gchar[size];
+    mTransparencyBitmapWidth = mBounds.width;
+  } else {
+    mTransparencyBitmapWidth = mBounds.width;
+  }
+  mTransparencyBitmapHeight = mBounds.height;
+
+  if (maskUpdate) {
+    cairo_surface_t* surface = cairo_image_surface_create(
+        CAIRO_FORMAT_A8, mTransparencyBitmapWidth, radius);
+    if (!surface) {
+      return;
+    }
+
+    cairo_t* cr = cairo_create(surface);
+
+    GtkWidgetState state;
+    memset((void*)&state, 0, sizeof(state));
+    GdkRectangle rect = {0, 0, mTransparencyBitmapWidth, radius};
+
+    moz_gtk_widget_paint(MOZ_GTK_HEADER_BAR, cr, &rect, &state, 0,
+                         GTK_TEXT_DIR_NONE);
+
+    cairo_destroy(cr);
+    cairo_surface_mark_dirty(surface);
+    cairo_surface_flush(surface);
+
+    UpdateMaskBits(mTransparencyBitmap, mTransparencyBitmapWidth, radius,
+                   nsIntRect(0, 0, mTransparencyBitmapWidth, radius),
+                   cairo_image_surface_get_data(surface),
+                   cairo_format_stride_for_width(CAIRO_FORMAT_A8,
+                                                 mTransparencyBitmapWidth));
+
+    cairo_surface_destroy(surface);
+  }
+
+#ifdef MOZ_X11
+  if (!mNeedsShow) {
+    Display* xDisplay = GDK_WINDOW_XDISPLAY(mGdkWindow);
+    Window xDrawable = GDK_WINDOW_XID(mGdkWindow);
+
+    Pixmap maskPixmap =
+        XCreateBitmapFromData(xDisplay, xDrawable, mTransparencyBitmap,
+                              mTransparencyBitmapWidth, radius);
+
+    XShapeCombineMask(xDisplay, xDrawable, ShapeBounding, 0, 0, maskPixmap,
+                      ShapeSet);
+
+    if (mTransparencyBitmapHeight > radius) {
+      XRectangle rect = {0, 0, (unsigned short)mTransparencyBitmapWidth,
+                         (unsigned short)(mTransparencyBitmapHeight - radius)};
+      XShapeCombineRectangles(xDisplay, xDrawable, ShapeBounding, 0, radius,
+                              &rect, 1, ShapeUnion, 0);
+    }
+
+    XFreePixmap(xDisplay, maskPixmap);
+  }
+#endif
+}
+
+GtkWidget* nsWindow::GetToplevelWidget() const { return mShell; }
+
+GdkWindow* nsWindow::GetToplevelGdkWindow() const {
+  return gtk_widget_get_window(mShell);
+}
+
+nsWindow* nsWindow::GetContainerWindow() const {
+  GtkWidget* owningWidget = GTK_WIDGET(mContainer);
+  if (!owningWidget) {
+    return nullptr;
+  }
+
+  nsWindow* window = get_window_for_gtk_widget(owningWidget);
+  NS_ASSERTION(window, "No nsWindow for container widget");
+  return window;
+}
+
+void nsWindow::SetUrgencyHint(GtkWidget* top_window, bool state) {
+  LOG("  nsWindow::SetUrgencyHint widget %p\n", top_window);
+  if (!top_window) {
+    return;
+  }
+  GdkWindow* window = gtk_widget_get_window(top_window);
+  if (!window) {
+    return;
+  }
+  // TODO: Use xdg-activation on Wayland?
+  gdk_window_set_urgency_hint(window, state);
+}
+
+void nsWindow::SetDefaultIcon(void) { SetIcon(u"default"_ns); }
+
+gint nsWindow::ConvertBorderStyles(BorderStyle aStyle) {
+  gint w = 0;
+
+  if (aStyle == BorderStyle::Default) {
+    return -1;
+  }
+
+  // note that we don't handle BorderStyle::Close yet
+  if (aStyle & BorderStyle::All) w |= GDK_DECOR_ALL;
+  if (aStyle & BorderStyle::Border) w |= GDK_DECOR_BORDER;
+  if (aStyle & BorderStyle::ResizeH) w |= GDK_DECOR_RESIZEH;
+  if (aStyle & BorderStyle::Title) w |= GDK_DECOR_TITLE;
+  if (aStyle & BorderStyle::Menu) w |= GDK_DECOR_MENU;
+  if (aStyle & BorderStyle::Minimize) w |= GDK_DECOR_MINIMIZE;
+  if (aStyle & BorderStyle::Maximize) w |= GDK_DECOR_MAXIMIZE;
+
+  return w;
+}
+
+class FullscreenTransitionWindow final : public nsISupports {
+ public:
+  NS_DECL_ISUPPORTS
+
+  explicit FullscreenTransitionWindow(GtkWidget* aWidget);
+
+  GtkWidget* mWindow;
+
+ private:
+  ~FullscreenTransitionWindow();
+};
+
+NS_IMPL_ISUPPORTS0(FullscreenTransitionWindow)
+
+FullscreenTransitionWindow::FullscreenTransitionWindow(GtkWidget* aWidget) {
+  mWindow = gtk_window_new(GTK_WINDOW_POPUP);
+  GtkWindow* gtkWin = GTK_WINDOW(mWindow);
+
+  gtk_window_set_type_hint(gtkWin, GDK_WINDOW_TYPE_HINT_SPLASHSCREEN);
+  GtkWindowSetTransientFor(gtkWin, GTK_WINDOW(aWidget));
+  gtk_window_set_decorated(gtkWin, false);
+
+  GdkWindow* gdkWin = gtk_widget_get_window(aWidget);
+  GdkScreen* screen = gtk_widget_get_screen(aWidget);
+  gint monitorNum = gdk_screen_get_monitor_at_window(screen, gdkWin);
+  GdkRectangle monitorRect;
+  gdk_screen_get_monitor_geometry(screen, monitorNum, &monitorRect);
+  gtk_window_set_screen(gtkWin, screen);
+  gtk_window_move(gtkWin, monitorRect.x, monitorRect.y);
+  MOZ_ASSERT(monitorRect.width > 0 && monitorRect.height > 0,
+             "Can't resize window smaller than 1x1.");
+  gtk_window_resize(gtkWin, monitorRect.width, monitorRect.height);
+
+  GdkRGBA bgColor;
+  bgColor.red = bgColor.green = bgColor.blue = 0.0;
+  bgColor.alpha = 1.0;
+  gtk_widget_override_background_color(mWindow, GTK_STATE_FLAG_NORMAL,
+                                       &bgColor);
+
+  gtk_widget_set_opacity(mWindow, 0.0);
+  gtk_widget_show(mWindow);
+}
+
+FullscreenTransitionWindow::~FullscreenTransitionWindow() {
+  gtk_widget_destroy(mWindow);
+}
+
+class FullscreenTransitionData {
+ public:
+  FullscreenTransitionData(nsIWidget::FullscreenTransitionStage aStage,
+                           uint16_t aDuration, nsIRunnable* aCallback,
+                           FullscreenTransitionWindow* aWindow)
+      : mStage(aStage),
+        mStartTime(TimeStamp::Now()),
+        mDuration(TimeDuration::FromMilliseconds(aDuration)),
+        mCallback(aCallback),
+        mWindow(aWindow) {}
+
+  static const guint sInterval = 1000 / 30;  // 30fps
+  static gboolean TimeoutCallback(gpointer aData);
+
+ private:
+  nsIWidget::FullscreenTransitionStage mStage;
+  TimeStamp mStartTime;
+  TimeDuration mDuration;
+  nsCOMPtr<nsIRunnable> mCallback;
+  RefPtr<FullscreenTransitionWindow> mWindow;
+};
+
+/* static */
+gboolean FullscreenTransitionData::TimeoutCallback(gpointer aData) {
+  bool finishing = false;
+  auto* data = static_cast<FullscreenTransitionData*>(aData);
+  gdouble opacity = (TimeStamp::Now() - data->mStartTime) / data->mDuration;
+  if (opacity >= 1.0) {
+    opacity = 1.0;
+    finishing = true;
+  }
+  if (data->mStage == nsIWidget::eAfterFullscreenToggle) {
+    opacity = 1.0 - opacity;
+  }
+  gtk_widget_set_opacity(data->mWindow->mWindow, opacity);
+
+  if (!finishing) {
+    return TRUE;
+  }
+  NS_DispatchToMainThread(data->mCallback.forget());
+  delete data;
+  return FALSE;
+}
+
+/* virtual */
+bool nsWindow::PrepareForFullscreenTransition(nsISupports** aData) {
+  if (!mCompositedScreen) {
+    return false;
+  }
+  *aData = do_AddRef(new FullscreenTransitionWindow(mShell)).take();
+  return true;
+}
+
+/* virtual */
+void nsWindow::PerformFullscreenTransition(FullscreenTransitionStage aStage,
+                                           uint16_t aDuration,
+                                           nsISupports* aData,
+                                           nsIRunnable* aCallback) {
+  auto* data = static_cast<FullscreenTransitionWindow*>(aData);
+  // This will be released at the end of the last timeout callback for it.
+  auto* transitionData =
+      new FullscreenTransitionData(aStage, aDuration, aCallback, data);
+  g_timeout_add_full(G_PRIORITY_HIGH, FullscreenTransitionData::sInterval,
+                     FullscreenTransitionData::TimeoutCallback, transitionData,
+                     nullptr);
+}
+
+already_AddRefed<widget::Screen> nsWindow::GetWidgetScreen() {
+  // Wayland can read screen directly
+  if (GdkIsWaylandDisplay()) {
+    if (RefPtr<Screen> screen = ScreenHelperGTK::GetScreenForWindow(this)) {
+      return screen.forget();
+    }
+  }
+
+  // GetScreenBounds() is slow for the GTK port so we override and use
+  // mBounds directly.
+  ScreenManager& screenManager = ScreenManager::GetSingleton();
+  LayoutDeviceIntRect bounds = mBounds;
+  DesktopIntRect deskBounds = RoundedToInt(bounds / GetDesktopToDeviceScale());
+  return screenManager.ScreenForRect(deskBounds);
+}
+
+RefPtr<VsyncDispatcher> nsWindow::GetVsyncDispatcher() {
+#ifdef MOZ_WAYLAND
+  if (mWaylandVsyncDispatcher) {
+    return mWaylandVsyncDispatcher;
+  }
+#endif
+  return nullptr;
+}
+
+bool nsWindow::SynchronouslyRepaintOnResize() {
+  if (GdkIsWaylandDisplay()) {
+    // See Bug 1734368
+    // Don't request synchronous repaint on HW accelerated backend - mesa can be
+    // deadlocked when it's missing back buffer and main event loop is blocked.
+    return false;
+  }
+
+  // default is synced repaint.
+  return true;
+}
+
+void nsWindow::KioskLockOnMonitor() {
+  // Available as of GTK 3.18+
+  static auto sGdkWindowFullscreenOnMonitor =
+      (void (*)(GdkWindow* window, gint monitor))dlsym(
+          RTLD_DEFAULT, "gdk_window_fullscreen_on_monitor");
+
+  if (!sGdkWindowFullscreenOnMonitor) {
+    return;
+  }
+
+  int monitor = mKioskMonitor.value();
+  if (monitor < 0 || monitor >= ScreenHelperGTK::GetMonitorCount()) {
+    LOG("nsWindow::KioskLockOnMonitor() wrong monitor number! (%d)\n", monitor);
+    return;
+  }
+
+  LOG("nsWindow::KioskLockOnMonitor() locked on %d\n", monitor);
+  sGdkWindowFullscreenOnMonitor(GetToplevelGdkWindow(), monitor);
+}
+
+static bool IsFullscreenSupported(GtkWidget* aShell) {
+#ifdef MOZ_X11
+  GdkScreen* screen = gtk_widget_get_screen(aShell);
+  GdkAtom atom = gdk_atom_intern("_NET_WM_STATE_FULLSCREEN", FALSE);
+  return gdk_x11_screen_supports_net_wm_hint(screen, atom);
+#else
+  return true;
+#endif
+}
+
+nsresult nsWindow::MakeFullScreen(bool aFullScreen) {
+  LOG("nsWindow::MakeFullScreen aFullScreen %d\n", aFullScreen);
+
+  if (GdkIsX11Display() && !IsFullscreenSupported(mShell)) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  if (aFullScreen) {
+    if (mSizeMode != nsSizeMode_Fullscreen &&
+        mSizeMode != nsSizeMode_Minimized) {
+      mLastSizeModeBeforeFullscreen = mSizeMode;
+    }
+    if (mIsPIPWindow) {
+      gtk_window_set_type_hint(GTK_WINDOW(mShell), GDK_WINDOW_TYPE_HINT_NORMAL);
+      if (gUseAspectRatio) {
+        mAspectRatioSaved = mAspectRatio;
+        mAspectRatio = 0.0f;
+        ApplySizeConstraints();
+      }
+    }
+
+    if (mKioskMonitor.isSome()) {
+      KioskLockOnMonitor();
+    } else {
+      gtk_window_fullscreen(GTK_WINDOW(mShell));
+    }
+  } else {
+    // Kiosk mode always use fullscreen mode.
+    if (gKioskMode) {
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+
+    gtk_window_unfullscreen(GTK_WINDOW(mShell));
+
+    if (mIsPIPWindow && gUseAspectRatio) {
+      mAspectRatio = mAspectRatioSaved;
+      // ApplySizeConstraints();
+    }
+  }
+
+  MOZ_ASSERT(mLastSizeModeBeforeFullscreen != nsSizeMode_Fullscreen);
+  return NS_OK;
+}
+
+void nsWindow::SetWindowDecoration(BorderStyle aStyle) {
+  LOG("nsWindow::SetWindowDecoration() Border style %x\n", int(aStyle));
+
+  // We can't use mGdkWindow directly here as it can be
+  // derived from mContainer which is not a top-level GdkWindow.
+  GdkWindow* window = GetToplevelGdkWindow();
+
+  // Sawfish, metacity, and presumably other window managers get
+  // confused if we change the window decorations while the window
+  // is visible.
+  bool wasVisible = false;
+  if (gdk_window_is_visible(window)) {
+    gdk_window_hide(window);
+    wasVisible = true;
+  }
+
+  gint wmd = ConvertBorderStyles(aStyle);
+  if (wmd != -1) gdk_window_set_decorations(window, (GdkWMDecoration)wmd);
+
+  if (wasVisible) gdk_window_show(window);
+
+    // For some window managers, adding or removing window decorations
+    // requires unmapping and remapping our toplevel window.  Go ahead
+    // and flush the queue here so that we don't end up with a BadWindow
+    // error later when this happens (when the persistence timer fires
+    // and GetWindowPos is called)
+#ifdef MOZ_X11
+  if (GdkIsX11Display()) {
+    XSync(GDK_DISPLAY_XDISPLAY(gdk_display_get_default()), X11False);
+  } else
+#endif /* MOZ_X11 */
+  {
+    gdk_flush();
+  }
+}
+
+void nsWindow::HideWindowChrome(bool aShouldHide) {
+  SetWindowDecoration(aShouldHide ? BorderStyle::None : mBorderStyle);
+}
+
+bool nsWindow::CheckForRollup(gdouble aMouseX, gdouble aMouseY, bool aIsWheel,
+                              bool aAlwaysRollup) {
+  LOG("nsWindow::CheckForRollup() aAlwaysRollup %d", aAlwaysRollup);
+  nsIRollupListener* rollupListener = GetActiveRollupListener();
+  nsCOMPtr<nsIWidget> rollupWidget;
+  if (rollupListener) {
+    rollupWidget = rollupListener->GetRollupWidget();
+  }
+  if (!rollupWidget) {
+    return false;
+  }
+
+  auto* rollupWindow =
+      (GdkWindow*)rollupWidget->GetNativeData(NS_NATIVE_WINDOW);
+  if (!aAlwaysRollup && is_mouse_in_window(rollupWindow, aMouseX, aMouseY)) {
+    return false;
+  }
+  bool retVal = false;
+  if (aIsWheel) {
+    retVal = rollupListener->ShouldConsumeOnMouseWheelEvent();
+    if (!rollupListener->ShouldRollupOnMouseWheelEvent()) {
+      return retVal;
+    }
+  }
+  LayoutDeviceIntPoint point;
+  nsIRollupListener::RollupOptions options{0,
+                                           nsIRollupListener::FlushViews::Yes};
+  // if we're dealing with menus, we probably have submenus and
+  // we don't want to rollup if the click is in a parent menu of
+  // the current submenu
+  if (!aAlwaysRollup) {
+    AutoTArray<nsIWidget*, 5> widgetChain;
+    uint32_t sameTypeCount =
+        rollupListener->GetSubmenuWidgetChain(&widgetChain);
+    for (unsigned long i = 0; i < widgetChain.Length(); ++i) {
+      nsIWidget* widget = widgetChain[i];
+      auto* currWindow = (GdkWindow*)widget->GetNativeData(NS_NATIVE_WINDOW);
+      if (is_mouse_in_window(currWindow, aMouseX, aMouseY)) {
+        // Don't roll up if the mouse event occurred within a menu of the same
+        // type.
+        // If the mouse event occurred in a menu higher than that, roll up, but
+        // pass the number of popups to Rollup so that only those of the same
+        // type close up.
+        if (i < sameTypeCount) {
+          return retVal;
+        }
+        options.mCount = sameTypeCount;
+        break;
+      }
+    }  // foreach parent menu widget
+    if (!aIsWheel) {
+      point = GdkEventCoordsToDevicePixels(aMouseX, aMouseY);
+      options.mPoint = &point;
+    }
+  }
+
+  if (mSizeMode == nsSizeMode_Minimized) {
+    // When we try to rollup in a minimized window, transitionend events for
+    // panels might not fire and thus we might not hide the popup after all,
+    // see bug 1810797.
+    options.mAllowAnimations = nsIRollupListener::AllowAnimations::No;
+  }
+
+  if (rollupListener->Rollup(options)) {
+    retVal = true;
+  }
+  return retVal;
+}
+
+/* static */
+bool nsWindow::DragInProgress() {
+  nsCOMPtr<nsIDragService> dragService =
+      do_GetService("@mozilla.org/widget/dragservice;1");
+  if (!dragService) {
+    return false;
+  }
+
+  nsCOMPtr<nsIDragSession> currentDragSession;
+  dragService->GetCurrentSession(getter_AddRefs(currentDragSession));
+  return !!currentDragSession;
+}
+
+// This is an ugly workaround for
+// https://bugzilla.mozilla.org/show_bug.cgi?id=1622107
+// We try to detect when Wayland compositor / gtk fails to deliver
+// info about finished D&D operations and cancel it on our own.
+MOZ_CAN_RUN_SCRIPT static void WaylandDragWorkaround(GdkEventButton* aEvent) {
+  static int buttonPressCountWithDrag = 0;
+
+  // We track only left button state as Firefox performs D&D on left
+  // button only.
+  if (aEvent->button != 1 || aEvent->type != GDK_BUTTON_PRESS) {
+    return;
+  }
+
+  nsCOMPtr<nsIDragService> dragService =
+      do_GetService("@mozilla.org/widget/dragservice;1");
+  if (!dragService) {
+    return;
+  }
+  nsCOMPtr<nsIDragSession> currentDragSession;
+  dragService->GetCurrentSession(getter_AddRefs(currentDragSession));
+
+  if (!currentDragSession) {
+    buttonPressCountWithDrag = 0;
+    return;
+  }
+
+  buttonPressCountWithDrag++;
+  if (buttonPressCountWithDrag > 1) {
+    NS_WARNING(
+        "Quit unfinished Wayland Drag and Drop operation. Buggy Wayland "
+        "compositor?");
+    buttonPressCountWithDrag = 0;
+    dragService->EndDragSession(false, 0);
+  }
+}
+
+static nsWindow* get_window_for_gtk_widget(GtkWidget* widget) {
+  gpointer user_data = g_object_get_data(G_OBJECT(widget), "nsWindow");
+  return static_cast<nsWindow*>(user_data);
+}
+
+static nsWindow* get_window_for_gdk_window(GdkWindow* window) {
+  gpointer user_data = g_object_get_data(G_OBJECT(window), "nsWindow");
+  return static_cast<nsWindow*>(user_data);
+}
+
+static bool is_mouse_in_window(GdkWindow* aWindow, gdouble aMouseX,
+                               gdouble aMouseY) {
+  GdkWindow* window = aWindow;
+  if (!window) {
+    return false;
+  }
+
+  gint x = 0;
+  gint y = 0;
+
+  {
+    gint offsetX = 0;
+    gint offsetY = 0;
+
+    while (window) {
+      gint tmpX = 0;
+      gint tmpY = 0;
+
+      gdk_window_get_position(window, &tmpX, &tmpY);
+      GtkWidget* widget = get_gtk_widget_for_gdk_window(window);
+
+      // if this is a window, compute x and y given its origin and our
+      // offset
+      if (GTK_IS_WINDOW(widget)) {
+        x = tmpX + offsetX;
+        y = tmpY + offsetY;
+        break;
+      }
+
+      offsetX += tmpX;
+      offsetY += tmpY;
+      window = gdk_window_get_parent(window);
+    }
+  }
+
+  gint margin = 0;
+  if (nsWindow* w = get_window_for_gdk_window(aWindow)) {
+    margin = w->GetInputRegionMarginInGdkCoords();
+  }
+
+  x += margin;
+  y += margin;
+
+  gint w = gdk_window_get_width(aWindow) - margin;
+  gint h = gdk_window_get_height(aWindow) - margin;
+
+  return aMouseX > x && aMouseX < x + w && aMouseY > y && aMouseY < y + h;
+}
+
+static GtkWidget* get_gtk_widget_for_gdk_window(GdkWindow* window) {
+  gpointer user_data = nullptr;
+  gdk_window_get_user_data(window, &user_data);
+
+  return GTK_WIDGET(user_data);
+}
+
+static GdkCursor* get_gtk_cursor(nsCursor aCursor) {
+  GdkCursor* gdkcursor = nullptr;
+  uint8_t newType = 0xff;
+
+  if ((gdkcursor = gCursorCache[aCursor])) {
+    return gdkcursor;
+  }
+
+  GdkDisplay* defaultDisplay = gdk_display_get_default();
+
+  switch (aCursor) {
+    case eCursor_standard:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "default");
+      break;
+    case eCursor_wait:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "wait");
+      break;
+    case eCursor_select:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "text");
+      break;
+    case eCursor_hyperlink:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "pointer");
+      break;
+    case eCursor_n_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "n-resize");
+      break;
+    case eCursor_s_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "s-resize");
+      break;
+    case eCursor_w_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "w-resize");
+      break;
+    case eCursor_e_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "e-resize");
+      break;
+    case eCursor_nw_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "nw-resize");
+      break;
+    case eCursor_se_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "se-resize");
+      break;
+    case eCursor_ne_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "ne-resize");
+      break;
+    case eCursor_sw_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "sw-resize");
+      break;
+    case eCursor_crosshair:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "crosshair");
+      break;
+    case eCursor_move:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "move");
+      break;
+    case eCursor_help:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "help");
+      break;
+    case eCursor_copy:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "copy");
+      if (!gdkcursor) newType = MOZ_CURSOR_COPY;
+      break;
+    case eCursor_alias:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "alias");
+      if (!gdkcursor) newType = MOZ_CURSOR_ALIAS;
+      break;
+    case eCursor_context_menu:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "context-menu");
+      if (!gdkcursor) newType = MOZ_CURSOR_CONTEXT_MENU;
+      break;
+    case eCursor_cell:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "cell");
+      break;
+    case eCursor_grab:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "grab");
+      if (!gdkcursor) newType = MOZ_CURSOR_HAND_GRAB;
+      break;
+    case eCursor_grabbing:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "grabbing");
+      if (!gdkcursor) newType = MOZ_CURSOR_HAND_GRABBING;
+      break;
+    case eCursor_spinning:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "progress");
+      if (!gdkcursor) newType = MOZ_CURSOR_SPINNING;
+      break;
+    case eCursor_zoom_in:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "zoom-in");
+      if (!gdkcursor) newType = MOZ_CURSOR_ZOOM_IN;
+      break;
+    case eCursor_zoom_out:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "zoom-out");
+      if (!gdkcursor) newType = MOZ_CURSOR_ZOOM_OUT;
+      break;
+    case eCursor_not_allowed:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "not-allowed");
+      if (!gdkcursor) newType = MOZ_CURSOR_NOT_ALLOWED;
+      break;
+    case eCursor_no_drop:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "no-drop");
+      if (!gdkcursor) {  // this nonstandard sequence makes it work on KDE and
+                         // GNOME
+        gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "forbidden");
+      }
+      if (!gdkcursor) {
+        gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "circle");
+      }
+      if (!gdkcursor) newType = MOZ_CURSOR_NOT_ALLOWED;
+      break;
+    case eCursor_vertical_text:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "vertical-text");
+      if (!gdkcursor) {
+        newType = MOZ_CURSOR_VERTICAL_TEXT;
+      }
+      break;
+    case eCursor_all_scroll:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "move");
+      break;
+    case eCursor_nesw_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "nesw-resize");
+      if (!gdkcursor) newType = MOZ_CURSOR_NESW_RESIZE;
+      break;
+    case eCursor_nwse_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "nwse-resize");
+      if (!gdkcursor) newType = MOZ_CURSOR_NWSE_RESIZE;
+      break;
+    case eCursor_ns_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "ns-resize");
+      break;
+    case eCursor_ew_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "ew-resize");
+      break;
+    case eCursor_row_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "row-resize");
+      break;
+    case eCursor_col_resize:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "col-resize");
+      break;
+    case eCursor_none:
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "none");
+      if (!gdkcursor) newType = MOZ_CURSOR_NONE;
+      break;
+    default:
+      NS_ASSERTION(aCursor, "Invalid cursor type");
+      gdkcursor = gdk_cursor_new_from_name(defaultDisplay, "default");
+      break;
+  }
+
+  // If by now we don't have a xcursor, this means we have to make a custom
+  // one. First, we try creating a named cursor based on the hash of our
+  // custom bitmap, as libXcursor has some magic to convert bitmapped cursors
+  // to themed cursors
+  if (newType != 0xFF && GtkCursors[newType].hash) {
+    gdkcursor =
+        gdk_cursor_new_from_name(defaultDisplay, GtkCursors[newType].hash);
+  }
+
+  // If we still don't have a xcursor, we now really create a bitmap cursor
+  if (newType != 0xff && !gdkcursor) {
+    GdkPixbuf* cursor_pixbuf =
+        gdk_pixbuf_new(GDK_COLORSPACE_RGB, TRUE, 8, 32, 32);
+    if (!cursor_pixbuf) {
+      return nullptr;
+    }
+
+    guchar* data = gdk_pixbuf_get_pixels(cursor_pixbuf);
+
+    // Read data from GtkCursors and compose RGBA surface from 1bit bitmap and
+    // mask GtkCursors bits and mask are 32x32 monochrome bitmaps (1 bit for
+    // each pixel) so it's 128 byte array (4 bytes for are one bitmap row and
+    // there are 32 rows here).
+    const unsigned char* bits = GtkCursors[newType].bits;
+    const unsigned char* mask_bits = GtkCursors[newType].mask_bits;
+
+    for (int i = 0; i < 128; i++) {
+      char bit = (char)*bits++;
+      char mask = (char)*mask_bits++;
+      for (int j = 0; j < 8; j++) {
+        unsigned char pix = ~(((bit >> j) & 0x01) * 0xff);
+        *data++ = pix;
+        *data++ = pix;
+        *data++ = pix;
+        *data++ = (((mask >> j) & 0x01) * 0xff);
+      }
+    }
+
+    gdkcursor = gdk_cursor_new_from_pixbuf(
+        gdk_display_get_default(), cursor_pixbuf, GtkCursors[newType].hot_x,
+        GtkCursors[newType].hot_y);
+
+    g_object_unref(cursor_pixbuf);
+  }
+
+  gCursorCache[aCursor] = gdkcursor;
+
+  return gdkcursor;
+}
+
+// gtk callbacks
+
+void draw_window_of_widget(GtkWidget* widget, GdkWindow* aWindow, cairo_t* cr) {
+  if (gtk_cairo_should_draw_window(cr, aWindow)) {
+    RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+    if (!window) {
+      NS_WARNING("Cannot get nsWindow from GtkWidget");
+    } else {
+      cairo_save(cr);
+      gtk_cairo_transform_to_window(cr, widget, aWindow);
+      // TODO - window->OnExposeEvent() can destroy this or other windows,
+      // do we need to handle it somehow?
+      window->OnExposeEvent(cr);
+      cairo_restore(cr);
+    }
+  }
+}
+
+/* static */
+gboolean expose_event_cb(GtkWidget* widget, cairo_t* cr) {
+  draw_window_of_widget(widget, gtk_widget_get_window(widget), cr);
+
+  // A strong reference is already held during "draw" signal emission,
+  // but GTK+ 3.4 wants the object to live a little longer than that
+  // (bug 1225970).
+  g_object_ref(widget);
+  g_idle_add(
+      [](gpointer data) -> gboolean {
+        g_object_unref(data);
+        return G_SOURCE_REMOVE;
+      },
+      widget);
+
+  return FALSE;
+}
+
+static gboolean configure_event_cb(GtkWidget* widget,
+                                   GdkEventConfigure* event) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return FALSE;
+  }
+
+  return window->OnConfigureEvent(widget, event);
+}
+
+// Some Gtk widget code may call gtk_widget_unrealize() which destroys
+// mGdkWindow. We need to listen on this signal and re-create
+// mGdkWindow when we're already mapped.
+static void widget_map_cb(GtkWidget* widget) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return;
+  }
+  window->OnMap();
+}
+
+static void widget_unmap_cb(GtkWidget* widget) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return;
+  }
+  window->OnUnmap();
+}
+
+static void size_allocate_cb(GtkWidget* widget, GtkAllocation* allocation) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return;
+  }
+
+  window->OnSizeAllocate(allocation);
+}
+
+static void toplevel_window_size_allocate_cb(GtkWidget* widget,
+                                             GtkAllocation* allocation) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return;
+  }
+
+  window->UpdateTopLevelOpaqueRegion();
+}
+
+static gboolean delete_event_cb(GtkWidget* widget, GdkEventAny* event) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return FALSE;
+  }
+
+  window->OnDeleteEvent();
+
+  return TRUE;
+}
+
+static gboolean enter_notify_event_cb(GtkWidget* widget,
+                                      GdkEventCrossing* event) {
+  RefPtr<nsWindow> window = get_window_for_gdk_window(event->window);
+  if (!window) {
+    return TRUE;
+  }
+
+  // We have stored leave notify - check if it's the correct one and
+  // fire it before enter notify in such case.
+  if (sStoredLeaveNotifyEvent) {
+    auto clearNofityEvent =
+        MakeScopeExit([&] { sStoredLeaveNotifyEvent = nullptr; });
+    if (event->x_root == sStoredLeaveNotifyEvent->x_root &&
+        event->y_root == sStoredLeaveNotifyEvent->y_root &&
+        window->ApplyEnterLeaveMutterWorkaround()) {
+      // Enter/Leave notify events has the same coordinates
+      // and uses know buggy window config.
+      // Consider it as a bogus one.
+      return TRUE;
+    }
+    RefPtr<nsWindow> leftWindow =
+        get_window_for_gdk_window(sStoredLeaveNotifyEvent->window);
+    if (leftWindow) {
+      leftWindow->OnLeaveNotifyEvent(sStoredLeaveNotifyEvent.get());
+    }
+  }
+
+  window->OnEnterNotifyEvent(event);
+  return TRUE;
+}
+
+static gboolean leave_notify_event_cb(GtkWidget* widget,
+                                      GdkEventCrossing* event) {
+  RefPtr<nsWindow> window = get_window_for_gdk_window(event->window);
+  if (!window) {
+    return TRUE;
+  }
+
+  if (window->ApplyEnterLeaveMutterWorkaround()) {
+    // The leave event is potentially wrong, don't fire it now but store
+    // it for further check at enter_notify_event_cb().
+    sStoredLeaveNotifyEvent.reset(reinterpret_cast<GdkEventCrossing*>(
+        gdk_event_copy(reinterpret_cast<GdkEvent*>(event))));
+  } else {
+    sStoredLeaveNotifyEvent = nullptr;
+    window->OnLeaveNotifyEvent(event);
+  }
+
+  return TRUE;
+}
+
+static nsWindow* GetFirstNSWindowForGDKWindow(GdkWindow* aGdkWindow) {
+  nsWindow* window;
+  while (!(window = get_window_for_gdk_window(aGdkWindow))) {
+    // The event has bubbled to the moz_container widget as passed into each
+    // caller's *widget parameter, but its corresponding nsWindow is an ancestor
+    // of the window that we need.  Instead, look at event->window and find the
+    // first ancestor nsWindow of it because event->window may be in a plugin.
+    aGdkWindow = gdk_window_get_parent(aGdkWindow);
+    if (!aGdkWindow) {
+      window = nullptr;
+      break;
+    }
+  }
+  return window;
+}
+
+static gboolean motion_notify_event_cb(GtkWidget* widget,
+                                       GdkEventMotion* event) {
+  UpdateLastInputEventTime(event);
+
+  RefPtr<nsWindow> window = GetFirstNSWindowForGDKWindow(event->window);
+  if (!window) {
+    return FALSE;
+  }
+
+  window->OnMotionNotifyEvent(event);
+
+  return TRUE;
+}
+
+static gboolean button_press_event_cb(GtkWidget* widget,
+                                      GdkEventButton* event) {
+  UpdateLastInputEventTime(event);
+
+  RefPtr<nsWindow> window = GetFirstNSWindowForGDKWindow(event->window);
+  if (!window) {
+    return FALSE;
+  }
+
+  window->OnButtonPressEvent(event);
+
+  if (GdkIsWaylandDisplay()) {
+    WaylandDragWorkaround(event);
+  }
+
+  return TRUE;
+}
+
+static gboolean button_release_event_cb(GtkWidget* widget,
+                                        GdkEventButton* event) {
+  UpdateLastInputEventTime(event);
+
+  RefPtr<nsWindow> window = GetFirstNSWindowForGDKWindow(event->window);
+  if (!window) {
+    return FALSE;
+  }
+
+  window->OnButtonReleaseEvent(event);
+
+  return TRUE;
+}
+
+static gboolean focus_in_event_cb(GtkWidget* widget, GdkEventFocus* event) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return FALSE;
+  }
+
+  window->OnContainerFocusInEvent(event);
+
+  return FALSE;
+}
+
+static gboolean focus_out_event_cb(GtkWidget* widget, GdkEventFocus* event) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return FALSE;
+  }
+
+  window->OnContainerFocusOutEvent(event);
+
+  return FALSE;
+}
+
+#ifdef MOZ_X11
+// For long-lived popup windows that don't really take focus themselves but
+// may have elements that accept keyboard input when the parent window is
+// active, focus is handled specially.  These windows include noautohide
+// panels.  (This special handling is not necessary for temporary popups where
+// the keyboard is grabbed.)
+//
+// Mousing over or clicking on these windows should not cause them to steal
+// focus from their parent windows, so, the input field of WM_HINTS is set to
+// False to request that the window manager not set the input focus to this
+// window.  http://tronche.com/gui/x/icccm/sec-4.html#s-4.1.7
+//
+// However, these windows can still receive WM_TAKE_FOCUS messages from the
+// window manager, so they can still detect when the user has indicated that
+// they wish to direct keyboard input at these windows.  When the window
+// manager offers focus to these windows (after a mouse over or click, for
+// example), a request to make the parent window active is issued.  When the
+// parent window becomes active, keyboard events will be received.
+
+static GdkFilterReturn popup_take_focus_filter(GdkXEvent* gdk_xevent,
+                                               GdkEvent* event, gpointer data) {
+  auto* xevent = static_cast<XEvent*>(gdk_xevent);
+  if (xevent->type != ClientMessage) {
+    return GDK_FILTER_CONTINUE;
+  }
+
+  XClientMessageEvent& xclient = xevent->xclient;
+  if (xclient.message_type != gdk_x11_get_xatom_by_name("WM_PROTOCOLS")) {
+    return GDK_FILTER_CONTINUE;
+  }
+
+  Atom atom = xclient.data.l[0];
+  if (atom != gdk_x11_get_xatom_by_name("WM_TAKE_FOCUS")) {
+    return GDK_FILTER_CONTINUE;
+  }
+
+  guint32 timestamp = xclient.data.l[1];
+
+  GtkWidget* widget = get_gtk_widget_for_gdk_window(event->any.window);
+  if (!widget) {
+    return GDK_FILTER_CONTINUE;
+  }
+
+  GtkWindow* parent = gtk_window_get_transient_for(GTK_WINDOW(widget));
+  if (!parent) {
+    return GDK_FILTER_CONTINUE;
+  }
+
+  if (gtk_window_is_active(parent)) {
+    return GDK_FILTER_REMOVE;  // leave input focus on the parent
+  }
+
+  GdkWindow* parent_window = gtk_widget_get_window(GTK_WIDGET(parent));
+  if (!parent_window) {
+    return GDK_FILTER_CONTINUE;
+  }
+
+  // In case the parent has not been deiconified.
+  gdk_window_show_unraised(parent_window);
+
+  // Request focus on the parent window.
+  // Use gdk_window_focus rather than gtk_window_present to avoid
+  // raising the parent window.
+  gdk_window_focus(parent_window, timestamp);
+  return GDK_FILTER_REMOVE;
+}
+#endif /* MOZ_X11 */
+
+static gboolean key_press_event_cb(GtkWidget* widget, GdkEventKey* event) {
+  LOGW("key_press_event_cb\n");
+
+  UpdateLastInputEventTime(event);
+
+  // find the window with focus and dispatch this event to that widget
+  nsWindow* window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return FALSE;
+  }
+
+  RefPtr<nsWindow> focusWindow = gFocusWindow ? gFocusWindow : window;
+
+#ifdef MOZ_X11
+  // Keyboard repeat can cause key press events to queue up when there are
+  // slow event handlers (bug 301029).  Throttle these events by removing
+  // consecutive pending duplicate KeyPress events to the same window.
+  // We use the event time of the last one.
+  // Note: GDK calls XkbSetDetectableAutorepeat so that KeyRelease events
+  // are generated only when the key is physically released.
+#  define NS_GDKEVENT_MATCH_MASK 0x1FFF  // GDK_SHIFT_MASK .. GDK_BUTTON5_MASK
+  // Our headers undefine X11 KeyPress - let's redefine it here.
+#  ifndef KeyPress
+#    define KeyPress 2
+#  endif
+  GdkDisplay* gdkDisplay = gtk_widget_get_display(widget);
+  if (GdkIsX11Display(gdkDisplay)) {
+    Display* dpy = GDK_DISPLAY_XDISPLAY(gdkDisplay);
+    while (XPending(dpy)) {
+      XEvent next_event;
+      XPeekEvent(dpy, &next_event);
+      GdkWindow* nextGdkWindow =
+          gdk_x11_window_lookup_for_display(gdkDisplay, next_event.xany.window);
+      if (nextGdkWindow != event->window || next_event.type != KeyPress ||
+          next_event.xkey.keycode != event->hardware_keycode ||
+          next_event.xkey.state != (event->state & NS_GDKEVENT_MATCH_MASK)) {
+        break;
+      }
+      XNextEvent(dpy, &next_event);
+      event->time = next_event.xkey.time;
+    }
+  }
+#endif
+
+  return focusWindow->OnKeyPressEvent(event);
+}
+
+static gboolean key_release_event_cb(GtkWidget* widget, GdkEventKey* event) {
+  LOGW("key_release_event_cb\n");
+
+  UpdateLastInputEventTime(event);
+
+  // find the window with focus and dispatch this event to that widget
+  nsWindow* window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return FALSE;
+  }
+
+  RefPtr<nsWindow> focusWindow = gFocusWindow ? gFocusWindow : window;
+  return focusWindow->OnKeyReleaseEvent(event);
+}
+
+static gboolean property_notify_event_cb(GtkWidget* aWidget,
+                                         GdkEventProperty* aEvent) {
+  RefPtr<nsWindow> window = get_window_for_gdk_window(aEvent->window);
+  if (!window) {
+    return FALSE;
+  }
+
+  return window->OnPropertyNotifyEvent(aWidget, aEvent);
+}
+
+static gboolean scroll_event_cb(GtkWidget* widget, GdkEventScroll* event) {
+  RefPtr<nsWindow> window = GetFirstNSWindowForGDKWindow(event->window);
+  if (NS_WARN_IF(!window)) {
+    return FALSE;
+  }
+
+  window->OnScrollEvent(event);
+
+  return TRUE;
+}
+
+static gboolean visibility_notify_event_cb(GtkWidget* widget,
+                                           GdkEventVisibility* event) {
+  RefPtr<nsWindow> window = get_window_for_gdk_window(event->window);
+  if (!window) {
+    return FALSE;
+  }
+  window->OnVisibilityNotifyEvent(event->state);
+  return TRUE;
+}
+
+static void hierarchy_changed_cb(GtkWidget* widget,
+                                 GtkWidget* previous_toplevel) {
+  GtkWidget* toplevel = gtk_widget_get_toplevel(widget);
+  GdkWindowState old_window_state = GDK_WINDOW_STATE_WITHDRAWN;
+  GdkEventWindowState event;
+
+  event.new_window_state = GDK_WINDOW_STATE_WITHDRAWN;
+
+  if (GTK_IS_WINDOW(previous_toplevel)) {
+    g_signal_handlers_disconnect_by_func(
+        previous_toplevel, FuncToGpointer(window_state_event_cb), widget);
+    GdkWindow* win = gtk_widget_get_window(previous_toplevel);
+    if (win) {
+      old_window_state = gdk_window_get_state(win);
+    }
+  }
+
+  if (GTK_IS_WINDOW(toplevel)) {
+    g_signal_connect_swapped(toplevel, "window-state-event",
+                             G_CALLBACK(window_state_event_cb), widget);
+    GdkWindow* win = gtk_widget_get_window(toplevel);
+    if (win) {
+      event.new_window_state = gdk_window_get_state(win);
+    }
+  }
+
+  event.changed_mask =
+      static_cast<GdkWindowState>(old_window_state ^ event.new_window_state);
+
+  if (event.changed_mask) {
+    event.type = GDK_WINDOW_STATE;
+    event.window = nullptr;
+    event.send_event = TRUE;
+    window_state_event_cb(widget, &event);
+  }
+}
+
+static gboolean window_state_event_cb(GtkWidget* widget,
+                                      GdkEventWindowState* event) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return FALSE;
+  }
+
+  window->OnWindowStateEvent(widget, event);
+
+  return FALSE;
+}
+
+static void settings_xft_dpi_changed_cb(GtkSettings* gtk_settings,
+                                        GParamSpec* pspec, nsWindow* data) {
+  RefPtr<nsWindow> window = data;
+  window->OnDPIChanged();
+  // Even though the window size in screen pixels has not changed,
+  // nsViewManager stores the dimensions in app units.
+  // DispatchResized() updates those.
+  window->DispatchResized();
+}
+
+static void check_resize_cb(GtkContainer* container, gpointer user_data) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(GTK_WIDGET(container));
+  if (!window) {
+    return;
+  }
+  window->OnCheckResize();
+}
+
+static void screen_composited_changed_cb(GdkScreen* screen,
+                                         gpointer user_data) {
+  // This callback can run before gfxPlatform::Init() in rare
+  // cases involving the profile manager. When this happens,
+  // we have no reason to reset any compositors as graphics
+  // hasn't been initialized yet.
+  if (GPUProcessManager::Get()) {
+    GPUProcessManager::Get()->ResetCompositors();
+  }
+}
+
+static void widget_composited_changed_cb(GtkWidget* widget,
+                                         gpointer user_data) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return;
+  }
+  window->OnCompositedChanged();
+}
+
+static void scale_changed_cb(GtkWidget* widget, GParamSpec* aPSpec,
+                             gpointer aPointer) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(widget);
+  if (!window) {
+    return;
+  }
+
+  window->OnScaleChanged(/* aNotify = */ true);
+}
+
+static gboolean touch_event_cb(GtkWidget* aWidget, GdkEventTouch* aEvent) {
+  UpdateLastInputEventTime(aEvent);
+
+  RefPtr<nsWindow> window = GetFirstNSWindowForGDKWindow(aEvent->window);
+  if (!window) {
+    return FALSE;
+  }
+
+  return window->OnTouchEvent(aEvent);
+}
+
+// This function called generic because there is no signal specific to touchpad
+// pinch events.
+static gboolean generic_event_cb(GtkWidget* widget, GdkEvent* aEvent) {
+  if (aEvent->type != GDK_TOUCHPAD_PINCH) {
+    return FALSE;
+  }
+  // Using reinterpret_cast because the touchpad_pinch field of GdkEvent is not
+  // available in GTK+ versions lower than v3.18
+  GdkEventTouchpadPinch* event =
+      reinterpret_cast<GdkEventTouchpadPinch*>(aEvent);
+
+  RefPtr<nsWindow> window = GetFirstNSWindowForGDKWindow(event->window);
+
+  if (!window) {
+    return FALSE;
+  }
+  return window->OnTouchpadPinchEvent(event);
+}
+
+//////////////////////////////////////////////////////////////////////
+// These are all of our drag and drop operations
+
+void nsWindow::InitDragEvent(WidgetDragEvent& aEvent) {
+  // set the keyboard modifiers
+  guint modifierState = KeymapWrapper::GetCurrentModifierState();
+  KeymapWrapper::InitInputEvent(aEvent, modifierState);
+}
+
+static LayoutDeviceIntPoint GetWindowDropPosition(nsWindow* aWindow, int aX,
+                                                  int aY) {
+  // Workaround for Bug 1710344
+  // Caused by Gtk issue https://gitlab.gnome.org/GNOME/gtk/-/issues/4437
+  if (aWindow->IsWaylandPopup()) {
+    int tx = 0, ty = 0;
+    gdk_window_get_position(aWindow->GetToplevelGdkWindow(), &tx, &ty);
+    aX += tx;
+    aY += ty;
+  }
+  LOGDRAG("WindowDropPosition [%d, %d]", aX, aY);
+  return aWindow->GdkPointToDevicePixels({aX, aY});
+}
+
+gboolean WindowDragMotionHandler(GtkWidget* aWidget,
+                                 GdkDragContext* aDragContext, gint aX, gint aY,
+                                 guint aTime) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(aWidget);
+  if (!window) {
+    return FALSE;
+  }
+
+  // figure out which internal widget this drag motion actually happened on
+  nscoord retx = 0;
+  nscoord rety = 0;
+
+  GdkWindow* innerWindow = get_inner_gdk_window(gtk_widget_get_window(aWidget),
+                                                aX, aY, &retx, &rety);
+  RefPtr<nsWindow> innerMostWindow = get_window_for_gdk_window(innerWindow);
+  if (!innerMostWindow) {
+    innerMostWindow = window;
+  }
+  LOGDRAG("WindowDragMotionHandler target nsWindow [%p]",
+          innerMostWindow.get());
+
+  RefPtr<nsDragService> dragService = nsDragService::GetInstance();
+  nsDragService::AutoEventLoop loop(dragService);
+  if (!dragService->ScheduleMotionEvent(
+          innerMostWindow, aDragContext,
+          GetWindowDropPosition(innerMostWindow, retx, rety), aTime)) {
+    return FALSE;
+  }
+  return TRUE;
+}
+
+static gboolean drag_motion_event_cb(GtkWidget* aWidget,
+                                     GdkDragContext* aDragContext, gint aX,
+                                     gint aY, guint aTime, gpointer aData) {
+  return WindowDragMotionHandler(aWidget, aDragContext, aX, aY, aTime);
+}
+
+void WindowDragLeaveHandler(GtkWidget* aWidget) {
+  LOGDRAG("WindowDragLeaveHandler()\n");
+
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(aWidget);
+  if (!window) {
+    LOGDRAG("    Failed - can't find nsWindow!\n");
+    return;
+  }
+
+  RefPtr<nsDragService> dragService = nsDragService::GetInstance();
+  nsDragService::AutoEventLoop loop(dragService);
+
+  nsWindow* mostRecentDragWindow = dragService->GetMostRecentDestWindow();
+  if (!mostRecentDragWindow) {
+    // This can happen when the target will not accept a drop.  A GTK drag
+    // source sends the leave message to the destination before the
+    // drag-failed signal on the source widget, but the leave message goes
+    // via the X server, and so doesn't get processed at least until the
+    // event loop runs again.
+    LOGDRAG("    Failed - GetMostRecentDestWindow()!\n");
+    return;
+  }
+
+  if (aWidget != window->GetGtkWidget()) {
+    // When the drag moves between widgets, GTK can send leave signal for
+    // the old widget after the motion or drop signal for the new widget.
+    // We'll send the leave event when the motion or drop event is run.
+    LOGDRAG("    Failed - GtkWidget mismatch!\n");
+    return;
+  }
+
+  LOGDRAG("WindowDragLeaveHandler nsWindow %p\n", (void*)mostRecentDragWindow);
+  dragService->ScheduleLeaveEvent();
+}
+
+static void drag_leave_event_cb(GtkWidget* aWidget,
+                                GdkDragContext* aDragContext, guint aTime,
+                                gpointer aData) {
+  WindowDragLeaveHandler(aWidget);
+}
+
+gboolean WindowDragDropHandler(GtkWidget* aWidget, GdkDragContext* aDragContext,
+                               gint aX, gint aY, guint aTime) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(aWidget);
+  if (!window) {
+    return FALSE;
+  }
+
+  // figure out which internal widget this drag motion actually happened on
+  nscoord retx = 0;
+  nscoord rety = 0;
+
+  GdkWindow* innerWindow = get_inner_gdk_window(gtk_widget_get_window(aWidget),
+                                                aX, aY, &retx, &rety);
+  RefPtr<nsWindow> innerMostWindow = get_window_for_gdk_window(innerWindow);
+
+  if (!innerMostWindow) {
+    innerMostWindow = window;
+  }
+
+  LOGDRAG("WindowDragDropHandler nsWindow [%p]", innerMostWindow.get());
+  RefPtr<nsDragService> dragService = nsDragService::GetInstance();
+  nsDragService::AutoEventLoop loop(dragService);
+  return dragService->ScheduleDropEvent(
+      innerMostWindow, aDragContext,
+      GetWindowDropPosition(innerMostWindow, retx, rety), aTime);
+}
+
+static gboolean drag_drop_event_cb(GtkWidget* aWidget,
+                                   GdkDragContext* aDragContext, gint aX,
+                                   gint aY, guint aTime, gpointer aData) {
+  return WindowDragDropHandler(aWidget, aDragContext, aX, aY, aTime);
+}
+
+static void drag_data_received_event_cb(GtkWidget* aWidget,
+                                        GdkDragContext* aDragContext, gint aX,
+                                        gint aY,
+                                        GtkSelectionData* aSelectionData,
+                                        guint aInfo, guint aTime,
+                                        gpointer aData) {
+  RefPtr<nsWindow> window = get_window_for_gtk_widget(aWidget);
+  if (!window) {
+    return;
+  }
+
+  window->OnDragDataReceivedEvent(aWidget, aDragContext, aX, aY, aSelectionData,
+                                  aInfo, aTime, aData);
+}
+
+static nsresult initialize_prefs(void) {
+  if (Preferences::HasUserValue("widget.use-aspect-ratio")) {
+    gUseAspectRatio = Preferences::GetBool("widget.use-aspect-ratio", true);
+  } else {
+    gUseAspectRatio = IsGnomeDesktopEnvironment() || IsKdeDesktopEnvironment();
+  }
+  return NS_OK;
+}
+
+// TODO: Can we simplify it for mShell/mContainer only scenario?
+static GdkWindow* get_inner_gdk_window(GdkWindow* aWindow, gint x, gint y,
+                                       gint* retx, gint* rety) {
+  gint cx, cy, cw, ch;
+  GList* children = gdk_window_peek_children(aWindow);
+  for (GList* child = g_list_last(children); child;
+       child = g_list_previous(child)) {
+    auto* childWindow = (GdkWindow*)child->data;
+    if (get_window_for_gdk_window(childWindow)) {
+      gdk_window_get_geometry(childWindow, &cx, &cy, &cw, &ch);
+      if ((cx < x) && (x < (cx + cw)) && (cy < y) && (y < (cy + ch)) &&
+          gdk_window_is_visible(childWindow)) {
+        return get_inner_gdk_window(childWindow, x - cx, y - cy, retx, rety);
+      }
+    }
+  }
+  *retx = x;
+  *rety = y;
+  return aWindow;
+}
+
+#ifdef ACCESSIBILITY
+void nsWindow::CreateRootAccessible() {
+  if (!mRootAccessible) {
+    LOG("nsWindow:: Create Toplevel Accessibility\n");
+    mRootAccessible = GetRootAccessible();
+  }
+}
+
+void nsWindow::DispatchEventToRootAccessible(uint32_t aEventType) {
+  if (!a11y::ShouldA11yBeEnabled()) {
+    return;
+  }
+
+  nsAccessibilityService* accService = GetOrCreateAccService();
+  if (!accService) {
+    return;
+  }
+
+  // Get the root document accessible and fire event to it.
+  a11y::LocalAccessible* acc = GetRootAccessible();
+  if (acc) {
+    accService->FireAccessibleEvent(aEventType, acc);
+  }
+}
+
+void nsWindow::DispatchActivateEventAccessible(void) {
+  DispatchEventToRootAccessible(nsIAccessibleEvent::EVENT_WINDOW_ACTIVATE);
+}
+
+void nsWindow::DispatchDeactivateEventAccessible(void) {
+  DispatchEventToRootAccessible(nsIAccessibleEvent::EVENT_WINDOW_DEACTIVATE);
+}
+
+void nsWindow::DispatchMaximizeEventAccessible(void) {
+  DispatchEventToRootAccessible(nsIAccessibleEvent::EVENT_WINDOW_MAXIMIZE);
+}
+
+void nsWindow::DispatchMinimizeEventAccessible(void) {
+  DispatchEventToRootAccessible(nsIAccessibleEvent::EVENT_WINDOW_MINIMIZE);
+}
+
+void nsWindow::DispatchRestoreEventAccessible(void) {
+  DispatchEventToRootAccessible(nsIAccessibleEvent::EVENT_WINDOW_RESTORE);
+}
+
+#endif /* #ifdef ACCESSIBILITY */
+
+void nsWindow::SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction) {
+  if (!mIMContext) {
+    return;
+  }
+  mIMContext->SetInputContext(this, &aContext, &aAction);
+}
+
+InputContext nsWindow::GetInputContext() {
+  InputContext context;
+  if (!mIMContext) {
+    context.mIMEState.mEnabled = IMEEnabled::Disabled;
+    context.mIMEState.mOpen = IMEState::OPEN_STATE_NOT_SUPPORTED;
+  } else {
+    context = mIMContext->GetInputContext();
+  }
+  return context;
+}
+
+TextEventDispatcherListener* nsWindow::GetNativeTextEventDispatcherListener() {
+  if (NS_WARN_IF(!mIMContext)) {
+    return nullptr;
+  }
+  return mIMContext;
+}
+
+bool nsWindow::GetEditCommands(NativeKeyBindingsType aType,
+                               const WidgetKeyboardEvent& aEvent,
+                               nsTArray<CommandInt>& aCommands) {
+  // Validate the arguments.
+  if (NS_WARN_IF(!nsIWidget::GetEditCommands(aType, aEvent, aCommands))) {
+    return false;
+  }
+
+  Maybe<WritingMode> writingMode;
+  if (aEvent.NeedsToRemapNavigationKey()) {
+    if (RefPtr<TextEventDispatcher> dispatcher = GetTextEventDispatcher()) {
+      writingMode = dispatcher->MaybeQueryWritingModeAtSelection();
+    }
+  }
+
+  NativeKeyBindings* keyBindings = NativeKeyBindings::GetInstance(aType);
+  keyBindings->GetEditCommands(aEvent, writingMode, aCommands);
+  return true;
+}
+
+already_AddRefed<DrawTarget> nsWindow::StartRemoteDrawingInRegion(
+    const LayoutDeviceIntRegion& aInvalidRegion, BufferMode* aBufferMode) {
+  return mSurfaceProvider.StartRemoteDrawingInRegion(aInvalidRegion,
+                                                     aBufferMode);
+}
+
+void nsWindow::EndRemoteDrawingInRegion(
+    DrawTarget* aDrawTarget, const LayoutDeviceIntRegion& aInvalidRegion) {
+  mSurfaceProvider.EndRemoteDrawingInRegion(aDrawTarget, aInvalidRegion);
+}
+
+bool nsWindow::GetDragInfo(WidgetMouseEvent* aMouseEvent, GdkWindow** aWindow,
+                           gint* aButton, gint* aRootX, gint* aRootY) {
+  if (aMouseEvent->mButton != MouseButton::ePrimary) {
+    // we can only begin a move drag with the left mouse button
+    return false;
+  }
+  *aButton = 1;
+
+  // get the gdk window for this widget
+  GdkWindow* gdk_window = mGdkWindow;
+  if (!gdk_window) {
+    return false;
+  }
+#ifdef DEBUG
+  // GDK_IS_WINDOW(...) expands to a statement-expression, and
+  // statement-expressions are not allowed in template-argument lists. So we
+  // have to make the MOZ_ASSERT condition indirect.
+  if (!GDK_IS_WINDOW(gdk_window)) {
+    MOZ_ASSERT(false, "must really be window");
+  }
+#endif
+
+  // find the top-level window
+  gdk_window = gdk_window_get_toplevel(gdk_window);
+  MOZ_ASSERT(gdk_window, "gdk_window_get_toplevel should not return null");
+  *aWindow = gdk_window;
+
+  if (!aMouseEvent->mWidget) {
+    return false;
+  }
+
+#ifdef MOZ_X11
+  if (GdkIsX11Display()) {
+    // Workaround for https://bugzilla.gnome.org/show_bug.cgi?id=789054
+    // To avoid crashes disable double-click on WM without _NET_WM_MOVERESIZE.
+    // See _should_perform_ewmh_drag() at gdkwindow-x11.c
+    // XXXsmaug remove this old hack. gtk should be fixed now.
+    GdkScreen* screen = gdk_window_get_screen(gdk_window);
+    GdkAtom atom = gdk_atom_intern("_NET_WM_MOVERESIZE", FALSE);
+    if (!gdk_x11_screen_supports_net_wm_hint(screen, atom)) {
+      static TimeStamp lastTimeStamp;
+      if (lastTimeStamp != aMouseEvent->mTimeStamp) {
+        lastTimeStamp = aMouseEvent->mTimeStamp;
+      } else {
+        return false;
+      }
+    }
+  }
+#endif
+
+  // FIXME: It would be nice to have the widget position at the time
+  // of the event, but it's relatively unlikely that the widget has
+  // moved since the mousedown.  (On the other hand, it's quite likely
+  // that the mouse has moved, which is why we use the mouse position
+  // from the event.)
+  LayoutDeviceIntPoint offset = aMouseEvent->mWidget->WidgetToScreenOffset();
+  *aRootX = aMouseEvent->mRefPoint.x + offset.x;
+  *aRootY = aMouseEvent->mRefPoint.y + offset.y;
+
+  return true;
+}
+
+nsIWidget::WindowRenderer* nsWindow::GetWindowRenderer() {
+  if (mIsDestroyed) {
+    // Prevent external code from triggering the re-creation of the
+    // LayerManager/Compositor during shutdown. Just return what we currently
+    // have, which is most likely null.
+    return mWindowRenderer;
+  }
+
+  return nsBaseWidget::GetWindowRenderer();
+}
+
+void nsWindow::DidGetNonBlankPaint() {
+  if (mGotNonBlankPaint) {
+    return;
+  }
+  mGotNonBlankPaint = true;
+  if (!mConfiguredClearColor) {
+    // Nothing to do, we hadn't overridden the clear color.
+    mConfiguredClearColor = true;
+    return;
+  }
+  // Reset the clear color set in the expose event to transparent.
+  GetWindowRenderer()->AsWebRender()->WrBridge()->SendSetDefaultClearColor(
+      NS_TRANSPARENT);
+}
+
+/* nsWindow::SetCompositorWidgetDelegate() sets remote GtkCompositorWidget
+ * to render into with compositor.
+ *
+ * SetCompositorWidgetDelegate(delegate) is called from
+ * nsBaseWidget::CreateCompositor(), i.e. nsWindow::GetWindowRenderer().
+ *
+ * SetCompositorWidgetDelegate(null) is called from
+ * nsBaseWidget::DestroyCompositor().
+ */
+void nsWindow::SetCompositorWidgetDelegate(CompositorWidgetDelegate* delegate) {
+  LOG("nsWindow::SetCompositorWidgetDelegate %p mIsMapped %d "
+      "mCompositorWidgetDelegate %p\n",
+      delegate, mIsMapped, mCompositorWidgetDelegate);
+
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+  if (delegate) {
+    mCompositorWidgetDelegate = delegate->AsPlatformSpecificDelegate();
+    MOZ_ASSERT(mCompositorWidgetDelegate,
+               "nsWindow::SetCompositorWidgetDelegate called with a "
+               "non-PlatformCompositorWidgetDelegate");
+    if (mIsMapped) {
+      ConfigureCompositor();
+    }
+  } else {
+    mCompositorWidgetDelegate = nullptr;
+  }
+}
+
+nsresult nsWindow::SetNonClientMargins(const LayoutDeviceIntMargin& aMargins) {
+  SetDrawsInTitlebar(aMargins.top == 0);
+  return NS_OK;
+}
+
+bool nsWindow::IsAlwaysUndecoratedWindow() const {
+  if (mIsPIPWindow || gKioskMode) {
+    return true;
+  }
+  if (mWindowType == WindowType::Dialog &&
+      mBorderStyle != BorderStyle::Default &&
+      mBorderStyle != BorderStyle::All &&
+      !(mBorderStyle & BorderStyle::Title) &&
+      !(mBorderStyle & BorderStyle::ResizeH)) {
+    return true;
+  }
+  return false;
+}
+
+void nsWindow::SetDrawsInTitlebar(bool aState) {
+  LOG("nsWindow::SetDrawsInTitlebar() State %d mGtkWindowDecoration %d\n",
+      aState, (int)mGtkWindowDecoration);
+
+  if (mGtkWindowDecoration == GTK_DECORATION_NONE ||
+      aState == mDrawInTitlebar) {
+    LOG("  already set, quit");
+    return;
+  }
+
+  if (mUndecorated) {
+    MOZ_ASSERT(aState, "Unexpected decoration request");
+    MOZ_ASSERT(!gtk_window_get_decorated(GTK_WINDOW(mShell)));
+    return;
+  }
+
+  mDrawInTitlebar = aState;
+
+  if (mGtkWindowDecoration == GTK_DECORATION_SYSTEM) {
+    SetWindowDecoration(aState ? BorderStyle::Border : mBorderStyle);
+  } else if (mGtkWindowDecoration == GTK_DECORATION_CLIENT) {
+    LOG("    Using CSD mode\n");
+
+    if (!gtk_widget_get_realized(GTK_WIDGET(mShell))) {
+      LOG("    Using CSD mode fast path\n");
+      gtk_window_set_titlebar(GTK_WINDOW(mShell),
+                              aState ? gtk_fixed_new() : nullptr);
+      return;
+    }
+
+    /* Window manager does not support GDK_DECOR_BORDER,
+     * emulate it by CSD.
+     *
+     * gtk_window_set_titlebar() works on unrealized widgets only,
+     * we need to handle mShell carefully here.
+     * When CSD is enabled mGdkWindow is owned by mContainer which is good
+     * as we can't delete our mGdkWindow. To make mShell unrealized while
+     * mContainer is preserved we temporary reparent mContainer to an
+     * invisible GtkWindow.
+     */
+    bool visible = !mNeedsShow && mIsShown;
+    if (visible) {
+      NativeShow(false);
+    }
+
+    // Using GTK_WINDOW_POPUP rather than
+    // GTK_WINDOW_TOPLEVEL in the hope that POPUP results in less
+    // initialization and window manager interaction.
+    GtkWidget* tmpWindow = gtk_window_new(GTK_WINDOW_POPUP);
+    gtk_widget_realize(tmpWindow);
+
+    gtk_widget_reparent(GTK_WIDGET(mContainer), tmpWindow);
+    gtk_widget_unrealize(GTK_WIDGET(mShell));
+
+    // Add a hidden titlebar widget to trigger CSD, but disable the default
+    // titlebar.  GtkFixed is a somewhat random choice for a simple unused
+    // widget. gtk_window_set_titlebar() takes ownership of the titlebar
+    // widget.
+    gtk_window_set_titlebar(GTK_WINDOW(mShell),
+                            aState ? gtk_fixed_new() : nullptr);
+
+    /* A workaround for https://bugzilla.gnome.org/show_bug.cgi?id=791081
+     * gtk_widget_realize() throws:
+     * "In pixman_region32_init_rect: Invalid rectangle passed"
+     * when mShell has default 1x1 size.
+     */
+    GtkAllocation allocation = {0, 0, 0, 0};
+    gtk_widget_get_preferred_width(GTK_WIDGET(mShell), nullptr,
+                                   &allocation.width);
+    gtk_widget_get_preferred_height(GTK_WIDGET(mShell), nullptr,
+                                    &allocation.height);
+    gtk_widget_size_allocate(GTK_WIDGET(mShell), &allocation);
+
+    gtk_widget_realize(GTK_WIDGET(mShell));
+    gtk_widget_reparent(GTK_WIDGET(mContainer), GTK_WIDGET(mShell));
+
+    // Label mShell toplevel window so property_notify_event_cb callback
+    // can find its way home.
+    g_object_set_data(G_OBJECT(GetToplevelGdkWindow()), "nsWindow", this);
+
+    if (AreBoundsSane()) {
+      GdkRectangle size = DevicePixelsToGdkSizeRoundUp(mBounds.Size());
+      LOG("    resize to %d x %d\n", size.width, size.height);
+      gtk_window_resize(GTK_WINDOW(mShell), size.width, size.height);
+    }
+
+    if (visible) {
+      mNeedsShow = true;
+      NativeShow(true);
+    }
+
+    gtk_widget_destroy(tmpWindow);
+  }
+
+  if (mTransparencyBitmapForTitlebar) {
+    if (mDrawInTitlebar && mSizeMode == nsSizeMode_Normal && !mIsTiled) {
+      UpdateTitlebarTransparencyBitmap();
+    } else {
+      ClearTransparencyBitmap();
+    }
+  } else {
+    SetTitlebarRect();
+  }
+}
+
+GtkWindow* nsWindow::GetCurrentTopmostWindow() const {
+  GtkWindow* parentWindow = GTK_WINDOW(GetGtkWidget());
+  GtkWindow* topmostParentWindow = nullptr;
+  while (parentWindow) {
+    topmostParentWindow = parentWindow;
+    parentWindow = gtk_window_get_transient_for(parentWindow);
+  }
+  return topmostParentWindow;
+}
+
+gint nsWindow::GdkCeiledScaleFactor() {
+  if (IsTopLevelWindowType()) {
+    return mCeiledScaleFactor;
+  }
+  if (nsWindow* topmost = GetTopmostWindow()) {
+    return topmost->mCeiledScaleFactor;
+  }
+  return ScreenHelperGTK::GetGTKMonitorScaleFactor();
+}
+
+double nsWindow::FractionalScaleFactor() {
+#ifdef MOZ_WAYLAND
+  double fractional_scale = [&] {
+    if (IsTopLevelWindowType()) {
+      return mFractionalScaleFactor;
+    }
+    if (nsWindow* topmost = GetTopmostWindow()) {
+      return topmost->mFractionalScaleFactor;
+    }
+    return 0.0;
+  }();
+  if (fractional_scale != 0.0) {
+    return fractional_scale;
+  }
+#endif
+  return GdkCeiledScaleFactor();
+}
+
+gint nsWindow::DevicePixelsToGdkCoordRoundUp(int aPixels) {
+  double scale = FractionalScaleFactor();
+  return ceil(aPixels / scale);
+}
+
+gint nsWindow::DevicePixelsToGdkCoordRoundDown(int aPixels) {
+  double scale = FractionalScaleFactor();
+  return floor(aPixels / scale);
+}
+
+GdkPoint nsWindow::DevicePixelsToGdkPointRoundDown(
+    const LayoutDeviceIntPoint& aPoint) {
+  double scale = FractionalScaleFactor();
+  return {int(aPoint.x / scale), int(aPoint.y / scale)};
+}
+
+GdkRectangle nsWindow::DevicePixelsToGdkRectRoundOut(
+    const LayoutDeviceIntRect& aRect) {
+  double scale = FractionalScaleFactor();
+  int x = floor(aRect.x / scale);
+  int y = floor(aRect.y / scale);
+  int right = ceil((aRect.x + aRect.width) / scale);
+  int bottom = ceil((aRect.y + aRect.height) / scale);
+  return {x, y, right - x, bottom - y};
+}
+
+GdkRectangle nsWindow::DevicePixelsToGdkSizeRoundUp(
+    const LayoutDeviceIntSize& aSize) {
+  double scale = FractionalScaleFactor();
+  gint width = ceil(aSize.width / scale);
+  gint height = ceil(aSize.height / scale);
+  return {0, 0, width, height};
+}
+
+int nsWindow::GdkCoordToDevicePixels(gint aCoord) {
+  return (int)(aCoord * FractionalScaleFactor());
+}
+
+LayoutDeviceIntPoint nsWindow::GdkEventCoordsToDevicePixels(gdouble aX,
+                                                            gdouble aY) {
+  double scale = FractionalScaleFactor();
+  return LayoutDeviceIntPoint::Floor((float)(aX * scale), (float)(aY * scale));
+}
+
+LayoutDeviceIntPoint nsWindow::GdkPointToDevicePixels(const GdkPoint& aPoint) {
+  double scale = FractionalScaleFactor();
+  return LayoutDeviceIntPoint::Floor((float)(aPoint.x * scale),
+                                     (float)(aPoint.y * scale));
+}
+
+LayoutDeviceIntRect nsWindow::GdkRectToDevicePixels(const GdkRectangle& aRect) {
+  double scale = FractionalScaleFactor();
+  return LayoutDeviceIntRect::RoundIn(
+      (float)(aRect.x * scale), (float)(aRect.y * scale),
+      (float)(aRect.width * scale), (float)(aRect.height * scale));
+}
+
+nsresult nsWindow::SynthesizeNativeMouseEvent(
+    LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+    MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+    nsIObserver* aObserver) {
+  LOG("SynthesizeNativeMouseEvent(%d, %d, %d, %d, %d)", aPoint.x.value,
+      aPoint.y.value, int(aNativeMessage), int(aButton), int(aModifierFlags));
+
+  AutoObserverNotifier notifier(aObserver, "mouseevent");
+
+  if (!mGdkWindow) {
+    return NS_OK;
+  }
+
+  // When a button-press/release event is requested, create it here and put it
+  // in the event queue. This will not emit a motion event - this needs to be
+  // done explicitly *before* requesting a button-press/release. You will also
+  // need to wait for the motion event to be dispatched before requesting a
+  // button-press/release event to maintain the desired event order.
+  switch (aNativeMessage) {
+    case NativeMouseMessage::ButtonDown:
+    case NativeMouseMessage::ButtonUp: {
+      GdkEvent event;
+      memset(&event, 0, sizeof(GdkEvent));
+      event.type = aNativeMessage == NativeMouseMessage::ButtonDown
+                       ? GDK_BUTTON_PRESS
+                       : GDK_BUTTON_RELEASE;
+      switch (aButton) {
+        case MouseButton::ePrimary:
+        case MouseButton::eMiddle:
+        case MouseButton::eSecondary:
+        case MouseButton::eX1:
+        case MouseButton::eX2:
+          event.button.button = aButton + 1;
+          break;
+        default:
+          return NS_ERROR_INVALID_ARG;
+      }
+      event.button.state =
+          KeymapWrapper::ConvertWidgetModifierToGdkState(aModifierFlags);
+      event.button.window = mGdkWindow;
+      event.button.time = GDK_CURRENT_TIME;
+
+      // Get device for event source
+      event.button.device = GdkGetPointer();
+
+      event.button.x_root = DevicePixelsToGdkCoordRoundDown(aPoint.x);
+      event.button.y_root = DevicePixelsToGdkCoordRoundDown(aPoint.y);
+
+      LayoutDeviceIntPoint pointInWindow = aPoint - WidgetToScreenOffset();
+      event.button.x = DevicePixelsToGdkCoordRoundDown(pointInWindow.x);
+      event.button.y = DevicePixelsToGdkCoordRoundDown(pointInWindow.y);
+
+      gdk_event_put(&event);
+      return NS_OK;
+    }
+    case NativeMouseMessage::Move: {
+      // We don't support specific events other than button-press/release. In
+      // all other cases we'll synthesize a motion event that will be emitted by
+      // gdk_display_warp_pointer().
+      // XXX How to activate native modifier for the other events?
+#ifdef MOZ_WAYLAND
+      // Impossible to warp the pointer on Wayland.
+      // For pointer lock, pointer-constraints and relative-pointer are used.
+      if (GdkIsWaylandDisplay()) {
+        return NS_OK;
+      }
+#endif
+      GdkScreen* screen = gdk_window_get_screen(mGdkWindow);
+      GdkPoint point = DevicePixelsToGdkPointRoundDown(aPoint);
+      gdk_device_warp(GdkGetPointer(), screen, point.x, point.y);
+      return NS_OK;
+    }
+    case NativeMouseMessage::EnterWindow:
+    case NativeMouseMessage::LeaveWindow:
+      MOZ_ASSERT_UNREACHABLE("Non supported mouse event on Linux");
+      return NS_ERROR_INVALID_ARG;
+  }
+  return NS_ERROR_UNEXPECTED;
+}
+
+void nsWindow::CreateAndPutGdkScrollEvent(mozilla::LayoutDeviceIntPoint aPoint,
+                                          double aDeltaX, double aDeltaY) {
+  GdkEvent event;
+  memset(&event, 0, sizeof(GdkEvent));
+  event.type = GDK_SCROLL;
+  event.scroll.window = mGdkWindow;
+  event.scroll.time = GDK_CURRENT_TIME;
+  // Get device for event source
+  GdkDisplay* display = gdk_window_get_display(mGdkWindow);
+  GdkDeviceManager* device_manager = gdk_display_get_device_manager(display);
+  // See note in nsWindow::SynthesizeNativeTouchpadPan about the device we use
+  // here.
+  event.scroll.device = gdk_device_manager_get_client_pointer(device_manager);
+  event.scroll.x_root = DevicePixelsToGdkCoordRoundDown(aPoint.x);
+  event.scroll.y_root = DevicePixelsToGdkCoordRoundDown(aPoint.y);
+
+  LayoutDeviceIntPoint pointInWindow = aPoint - WidgetToScreenOffset();
+  event.scroll.x = DevicePixelsToGdkCoordRoundDown(pointInWindow.x);
+  event.scroll.y = DevicePixelsToGdkCoordRoundDown(pointInWindow.y);
+
+  // The delta values are backwards on Linux compared to Windows and Cocoa,
+  // hence the negation.
+  event.scroll.direction = GDK_SCROLL_SMOOTH;
+  event.scroll.delta_x = -aDeltaX;
+  event.scroll.delta_y = -aDeltaY;
+
+  gdk_event_put(&event);
+}
+
+nsresult nsWindow::SynthesizeNativeMouseScrollEvent(
+    mozilla::LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage,
+    double aDeltaX, double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+    uint32_t aAdditionalFlags, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "mousescrollevent");
+
+  if (!mGdkWindow) {
+    return NS_OK;
+  }
+
+  CreateAndPutGdkScrollEvent(aPoint, aDeltaX, aDeltaY);
+
+  return NS_OK;
+}
+
+nsresult nsWindow::SynthesizeNativeTouchPoint(uint32_t aPointerId,
+                                              TouchPointerState aPointerState,
+                                              LayoutDeviceIntPoint aPoint,
+                                              double aPointerPressure,
+                                              uint32_t aPointerOrientation,
+                                              nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchpoint");
+
+  if (!mGdkWindow) {
+    return NS_OK;
+  }
+
+  GdkEvent event;
+  memset(&event, 0, sizeof(GdkEvent));
+
+  static std::map<uint32_t, GdkEventSequence*> sKnownPointers;
+
+  auto result = sKnownPointers.find(aPointerId);
+  switch (aPointerState) {
+    case TOUCH_CONTACT:
+      if (result == sKnownPointers.end()) {
+        // GdkEventSequence isn't a thing we can instantiate, and never gets
+        // dereferenced in the gtk code. It's an opaque pointer, the only
+        // requirement is that it be distinct from other instances of
+        // GdkEventSequence*.
+        event.touch.sequence = (GdkEventSequence*)((uintptr_t)aPointerId);
+        sKnownPointers[aPointerId] = event.touch.sequence;
+        event.type = GDK_TOUCH_BEGIN;
+      } else {
+        event.touch.sequence = result->second;
+        event.type = GDK_TOUCH_UPDATE;
+      }
+      break;
+    case TOUCH_REMOVE:
+      event.type = GDK_TOUCH_END;
+      if (result == sKnownPointers.end()) {
+        NS_WARNING("Tried to synthesize touch-end for unknown pointer!");
+        return NS_ERROR_UNEXPECTED;
+      }
+      event.touch.sequence = result->second;
+      sKnownPointers.erase(result);
+      break;
+    case TOUCH_CANCEL:
+      event.type = GDK_TOUCH_CANCEL;
+      if (result == sKnownPointers.end()) {
+        NS_WARNING("Tried to synthesize touch-cancel for unknown pointer!");
+        return NS_ERROR_UNEXPECTED;
+      }
+      event.touch.sequence = result->second;
+      sKnownPointers.erase(result);
+      break;
+    case TOUCH_HOVER:
+    default:
+      return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  event.touch.window = mGdkWindow;
+  event.touch.time = GDK_CURRENT_TIME;
+
+  GdkDisplay* display = gdk_window_get_display(mGdkWindow);
+  GdkDeviceManager* device_manager = gdk_display_get_device_manager(display);
+  event.touch.device = gdk_device_manager_get_client_pointer(device_manager);
+
+  event.touch.x_root = DevicePixelsToGdkCoordRoundDown(aPoint.x);
+  event.touch.y_root = DevicePixelsToGdkCoordRoundDown(aPoint.y);
+
+  LayoutDeviceIntPoint pointInWindow = aPoint - WidgetToScreenOffset();
+  event.touch.x = DevicePixelsToGdkCoordRoundDown(pointInWindow.x);
+  event.touch.y = DevicePixelsToGdkCoordRoundDown(pointInWindow.y);
+
+  gdk_event_put(&event);
+
+  return NS_OK;
+}
+
+nsresult nsWindow::SynthesizeNativeTouchPadPinch(
+    TouchpadGesturePhase aEventPhase, float aScale, LayoutDeviceIntPoint aPoint,
+    int32_t aModifierFlags) {
+  if (!mGdkWindow) {
+    return NS_OK;
+  }
+  GdkEvent event;
+  memset(&event, 0, sizeof(GdkEvent));
+
+  GdkEventTouchpadPinch* touchpad_event =
+      reinterpret_cast<GdkEventTouchpadPinch*>(&event);
+  touchpad_event->type = GDK_TOUCHPAD_PINCH;
+
+  const ScreenIntPoint widgetToScreenOffset = ViewAs<ScreenPixel>(
+      WidgetToScreenOffset(),
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+
+  ScreenPoint pointInWindow =
+      ViewAs<ScreenPixel>(
+          aPoint,
+          PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent) -
+      widgetToScreenOffset;
+
+  gdouble dx = 0, dy = 0;
+
+  switch (aEventPhase) {
+    case PHASE_BEGIN:
+      touchpad_event->phase = GDK_TOUCHPAD_GESTURE_PHASE_BEGIN;
+      mCurrentSynthesizedTouchpadPinch = {pointInWindow, pointInWindow};
+      break;
+    case PHASE_UPDATE:
+      dx = pointInWindow.x - mCurrentSynthesizedTouchpadPinch.mCurrentFocus.x;
+      dy = pointInWindow.y - mCurrentSynthesizedTouchpadPinch.mCurrentFocus.y;
+      mCurrentSynthesizedTouchpadPinch.mCurrentFocus = pointInWindow;
+      touchpad_event->phase = GDK_TOUCHPAD_GESTURE_PHASE_UPDATE;
+      break;
+    case PHASE_END:
+      touchpad_event->phase = GDK_TOUCHPAD_GESTURE_PHASE_END;
+      break;
+
+    default:
+      return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  touchpad_event->window = mGdkWindow;
+  // We only set the fields of GdkEventTouchpadPinch which are
+  // actually used in OnTouchpadPinchEvent().
+  // GdkEventTouchpadPinch has additional fields.
+  // If OnTouchpadPinchEvent() is changed to use other fields, this function
+  // will need to change to set them as well.
+  touchpad_event->time = GDK_CURRENT_TIME;
+  touchpad_event->scale = aScale;
+  touchpad_event->x_root = DevicePixelsToGdkCoordRoundDown(
+      mCurrentSynthesizedTouchpadPinch.mBeginFocus.x +
+      ScreenCoord(widgetToScreenOffset.x));
+  touchpad_event->y_root = DevicePixelsToGdkCoordRoundDown(
+      mCurrentSynthesizedTouchpadPinch.mBeginFocus.y +
+      ScreenCoord(widgetToScreenOffset.y));
+
+  touchpad_event->x = DevicePixelsToGdkCoordRoundDown(
+      mCurrentSynthesizedTouchpadPinch.mBeginFocus.x);
+  touchpad_event->y = DevicePixelsToGdkCoordRoundDown(
+      mCurrentSynthesizedTouchpadPinch.mBeginFocus.y);
+
+  touchpad_event->dx = dx;
+  touchpad_event->dy = dy;
+
+  touchpad_event->state = aModifierFlags;
+
+  gdk_event_put(&event);
+
+  return NS_OK;
+}
+
+nsresult nsWindow::SynthesizeNativeTouchpadPan(TouchpadGesturePhase aEventPhase,
+                                               LayoutDeviceIntPoint aPoint,
+                                               double aDeltaX, double aDeltaY,
+                                               int32_t aModifierFlags,
+                                               nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchpadpanevent");
+
+  if (!mGdkWindow) {
+    return NS_OK;
+  }
+
+  // This should/could maybe send GdkEventTouchpadSwipe events, however we don't
+  // currently consume those (either real user input or testing events). So we
+  // send gdk scroll events to be more like what we do for real user input. If
+  // we start consuming GdkEventTouchpadSwipe and get those hooked up to swipe
+  // to nav, then maybe we should test those too.
+
+  mCurrentSynthesizedTouchpadPan.mTouchpadGesturePhase = Some(aEventPhase);
+  MOZ_ASSERT(mCurrentSynthesizedTouchpadPan.mSavedObserver == 0);
+  mCurrentSynthesizedTouchpadPan.mSavedObserver = notifier.SaveObserver();
+
+  // Note that CreateAndPutGdkScrollEvent sets the device source for the created
+  // event as the "client pointer" (a kind of default device) which will
+  // probably be of type mouse. We would ideally want to set the device of the
+  // created event to be a touchpad, but the system might not have a touchpad.
+  // To get around this we use
+  // mCurrentSynthesizedTouchpadPan.mTouchpadGesturePhase being something to
+  // indicate that we should treat the source of the event as touchpad in
+  // OnScrollEvent.
+  CreateAndPutGdkScrollEvent(aPoint, aDeltaX, aDeltaY);
+
+  return NS_OK;
+}
+
+nsWindow::GtkWindowDecoration nsWindow::GetSystemGtkWindowDecoration() {
+  static GtkWindowDecoration sGtkWindowDecoration = [] {
+    // Allow MOZ_GTK_TITLEBAR_DECORATION to override our heuristics
+    if (const char* decorationOverride =
+            getenv("MOZ_GTK_TITLEBAR_DECORATION")) {
+      if (strcmp(decorationOverride, "none") == 0) {
+        return GTK_DECORATION_NONE;
+      }
+      if (strcmp(decorationOverride, "client") == 0) {
+        return GTK_DECORATION_CLIENT;
+      }
+      if (strcmp(decorationOverride, "system") == 0) {
+        return GTK_DECORATION_SYSTEM;
+      }
+    }
+
+    // nsWindow::GetSystemGtkWindowDecoration can be called from various
+    // threads so we can't use gfxPlatformGtk here.
+    if (GdkIsWaylandDisplay()) {
+      return GTK_DECORATION_CLIENT;
+    }
+
+    // GTK_CSD forces CSD mode - use also CSD because window manager
+    // decorations does not work with CSD.
+    // We check GTK_CSD as well as gtk_window_should_use_csd() does.
+    if (const char* csdOverride = getenv("GTK_CSD")) {
+      return *csdOverride == '0' ? GTK_DECORATION_NONE : GTK_DECORATION_CLIENT;
+    }
+
+    // TODO: Consider switching this to GetDesktopEnvironmentIdentifier().
+    const char* currentDesktop = getenv("XDG_CURRENT_DESKTOP");
+    if (!currentDesktop) {
+      return GTK_DECORATION_NONE;
+    }
+    if (strstr(currentDesktop, "i3")) {
+      return GTK_DECORATION_NONE;
+    }
+
+    // Tested desktops: pop:GNOME, KDE, Enlightenment, LXDE, openbox, MATE,
+    // X-Cinnamon, Pantheon, Deepin, GNOME, LXQt, Unity.
+    return GTK_DECORATION_CLIENT;
+  }();
+  return sGtkWindowDecoration;
+}
+
+bool nsWindow::TitlebarUseShapeMask() {
+  static int useShapeMask = []() {
+    // Don't use titlebar shape mask on Wayland
+    if (!GdkIsX11Display()) {
+      return false;
+    }
+
+    // We can't use shape masks on Mutter/X.org as we can't resize Firefox
+    // window there (Bug 1530252).
+    if (IsGnomeDesktopEnvironment()) {
+      return false;
+    }
+
+    return Preferences::GetBool("widget.titlebar-x11-use-shape-mask", false);
+  }();
+  return useShapeMask;
+}
+
+int32_t nsWindow::RoundsWidgetCoordinatesTo() { return GdkCeiledScaleFactor(); }
+
+void nsWindow::GetCompositorWidgetInitData(
+    mozilla::widget::CompositorWidgetInitData* aInitData) {
+  nsCString displayName;
+
+  LOG("nsWindow::GetCompositorWidgetInitData");
+
+  *aInitData = mozilla::widget::GtkCompositorWidgetInitData(
+      GetX11Window(), displayName, GetShapedState(), GdkIsX11Display(),
+      GetClientSize());
+
+#ifdef MOZ_X11
+  if (GdkIsX11Display()) {
+    // Make sure the window XID is propagated to X server, we can fail otherwise
+    // in GPU process (Bug 1401634).
+    Display* display = DefaultXDisplay();
+    XFlush(display);
+    displayName = nsCString(XDisplayString(display));
+  }
+#endif
+}
+
+#ifdef MOZ_X11
+/* XApp progress support currently works by setting a property
+ * on a window with this Atom name.  A supporting window manager
+ * will notice this and pass it along to whatever handling has
+ * been implemented on that end (e.g. passing it on to a taskbar
+ * widget.)  There is no issue if WM support is lacking, this is
+ * simply ignored in that case.
+ *
+ * See https://github.com/linuxmint/xapps/blob/master/libxapp/xapp-gtk-window.c
+ * for further details.
+ */
+
+#  define PROGRESS_HINT "_NET_WM_XAPP_PROGRESS"
+
+static void set_window_hint_cardinal(Window xid, const gchar* atom_name,
+                                     gulong cardinal) {
+  GdkDisplay* display;
+
+  display = gdk_display_get_default();
+
+  if (cardinal > 0) {
+    XChangeProperty(GDK_DISPLAY_XDISPLAY(display), xid,
+                    gdk_x11_get_xatom_by_name_for_display(display, atom_name),
+                    XA_CARDINAL, 32, PropModeReplace, (guchar*)&cardinal, 1);
+  } else {
+    XDeleteProperty(GDK_DISPLAY_XDISPLAY(display), xid,
+                    gdk_x11_get_xatom_by_name_for_display(display, atom_name));
+  }
+}
+#endif  // MOZ_X11
+
+void nsWindow::SetProgress(unsigned long progressPercent) {
+#ifdef MOZ_X11
+
+  if (!GdkIsX11Display()) {
+    return;
+  }
+
+  if (!mShell) {
+    return;
+  }
+
+  progressPercent = MIN(progressPercent, 100);
+
+  set_window_hint_cardinal(GDK_WINDOW_XID(GetToplevelGdkWindow()),
+                           PROGRESS_HINT, progressPercent);
+#endif  // MOZ_X11
+}
+
+#ifdef MOZ_X11
+void nsWindow::SetCompositorHint(WindowComposeRequest aState) {
+  if (!GdkIsX11Display()) {
+    return;
+  }
+
+  gulong value = aState;
+  GdkAtom cardinal_atom = gdk_x11_xatom_to_atom(XA_CARDINAL);
+  gdk_property_change(GetToplevelGdkWindow(),
+                      gdk_atom_intern("_NET_WM_BYPASS_COMPOSITOR", FALSE),
+                      cardinal_atom,
+                      32,  // format
+                      GDK_PROP_MODE_REPLACE, (guchar*)&value, 1);
+}
+#endif
+
+nsresult nsWindow::SetSystemFont(const nsCString& aFontName) {
+  GtkSettings* settings = gtk_settings_get_default();
+  g_object_set(settings, "gtk-font-name", aFontName.get(), nullptr);
+  return NS_OK;
+}
+
+nsresult nsWindow::GetSystemFont(nsCString& aFontName) {
+  GtkSettings* settings = gtk_settings_get_default();
+  gchar* fontName = nullptr;
+  g_object_get(settings, "gtk-font-name", &fontName, nullptr);
+  if (fontName) {
+    aFontName.Assign(fontName);
+    g_free(fontName);
+  }
+  return NS_OK;
+}
+
+already_AddRefed<nsIWidget> nsIWidget::CreateTopLevelWindow() {
+  nsCOMPtr<nsIWidget> window = new nsWindow();
+  return window.forget();
+}
+
+already_AddRefed<nsIWidget> nsIWidget::CreateChildWindow() {
+  nsCOMPtr<nsIWidget> window = new nsWindow();
+  return window.forget();
+}
+
+#ifdef MOZ_WAYLAND
+static void relative_pointer_handle_relative_motion(
+    void* data, struct zwp_relative_pointer_v1* pointer, uint32_t time_hi,
+    uint32_t time_lo, wl_fixed_t dx_w, wl_fixed_t dy_w, wl_fixed_t dx_unaccel_w,
+    wl_fixed_t dy_unaccel_w) {
+  RefPtr<nsWindow> window(reinterpret_cast<nsWindow*>(data));
+
+  WidgetMouseEvent event(true, eMouseMove, window, WidgetMouseEvent::eReal);
+
+  double scale = window->FractionalScaleFactor();
+  event.mRefPoint = window->GetNativePointerLockCenter();
+  event.mRefPoint.x += int(wl_fixed_to_double(dx_w) * scale);
+  event.mRefPoint.y += int(wl_fixed_to_double(dy_w) * scale);
+
+  event.AssignEventTime(window->GetWidgetEventTime(time_lo));
+  window->DispatchInputEvent(&event);
+}
+
+static const struct zwp_relative_pointer_v1_listener relative_pointer_listener =
+    {
+        relative_pointer_handle_relative_motion,
+};
+
+void nsWindow::SetNativePointerLockCenter(
+    const LayoutDeviceIntPoint& aLockCenter) {
+  mNativePointerLockCenter = aLockCenter;
+}
+
+void nsWindow::LockNativePointer() {
+  if (!GdkIsWaylandDisplay()) {
+    return;
+  }
+
+  auto* waylandDisplay = WaylandDisplayGet();
+
+  auto* pointerConstraints = waylandDisplay->GetPointerConstraints();
+  if (!pointerConstraints) {
+    return;
+  }
+
+  auto* relativePointerMgr = waylandDisplay->GetRelativePointerManager();
+  if (!relativePointerMgr) {
+    return;
+  }
+
+  GdkDisplay* display = gdk_display_get_default();
+
+  GdkDeviceManager* manager = gdk_display_get_device_manager(display);
+  MOZ_ASSERT(manager);
+
+  GdkDevice* device = gdk_device_manager_get_client_pointer(manager);
+  if (!device) {
+    NS_WARNING("Could not find Wayland pointer to lock");
+    return;
+  }
+  wl_pointer* pointer = gdk_wayland_device_get_wl_pointer(device);
+  MOZ_ASSERT(pointer);
+
+  wl_surface* surface =
+      gdk_wayland_window_get_wl_surface(GetToplevelGdkWindow());
+  if (!surface) {
+    /* Can be null when the window is hidden.
+     * Though it's unlikely that a lock request comes in that case, be
+     * defensive. */
+    return;
+  }
+
+  if (mLockedPointer || mRelativePointer) {
+    UnlockNativePointer();
+  }
+
+  mLockedPointer = zwp_pointer_constraints_v1_lock_pointer(
+      pointerConstraints, surface, pointer, nullptr,
+      ZWP_POINTER_CONSTRAINTS_V1_LIFETIME_PERSISTENT);
+  if (!mLockedPointer) {
+    NS_WARNING("Could not lock Wayland pointer");
+    return;
+  }
+
+  mRelativePointer = zwp_relative_pointer_manager_v1_get_relative_pointer(
+      relativePointerMgr, pointer);
+  if (!mRelativePointer) {
+    NS_WARNING("Could not create relative Wayland pointer");
+    zwp_locked_pointer_v1_destroy(mLockedPointer);
+    mLockedPointer = nullptr;
+    return;
+  }
+
+  zwp_relative_pointer_v1_add_listener(mRelativePointer,
+                                       &relative_pointer_listener, this);
+}
+
+void nsWindow::UnlockNativePointer() {
+  if (!GdkIsWaylandDisplay()) {
+    return;
+  }
+  if (mRelativePointer) {
+    zwp_relative_pointer_v1_destroy(mRelativePointer);
+    mRelativePointer = nullptr;
+  }
+  if (mLockedPointer) {
+    zwp_locked_pointer_v1_destroy(mLockedPointer);
+    mLockedPointer = nullptr;
+  }
+}
+#endif
+
+bool nsWindow::GetTopLevelWindowActiveState(nsIFrame* aFrame) {
+  // Used by window frame and button box rendering. We can end up in here in
+  // the content process when rendering one of these moz styles freely in a
+  // page. Fail in this case, there is no applicable window focus state.
+  if (!XRE_IsParentProcess()) {
+    return false;
+  }
+  // All headless windows are considered active so they are painted.
+  if (gfxPlatform::IsHeadless()) {
+    return true;
+  }
+  // Get the widget. nsIFrame's GetNearestWidget walks up the view chain
+  // until it finds a real window.
+  nsWindow* window = static_cast<nsWindow*>(aFrame->GetNearestWidget());
+  if (!window) {
+    return false;
+  }
+  return !window->mTitlebarBackdropState;
+}
+
+static nsIFrame* FindTitlebarFrame(nsIFrame* aFrame) {
+  for (nsIFrame* childFrame : aFrame->PrincipalChildList()) {
+    StyleAppearance appearance =
+        childFrame->StyleDisplay()->EffectiveAppearance();
+    if (appearance == StyleAppearance::MozWindowTitlebar ||
+        appearance == StyleAppearance::MozWindowTitlebarMaximized) {
+      return childFrame;
+    }
+
+    if (nsIFrame* foundFrame = FindTitlebarFrame(childFrame)) {
+      return foundFrame;
+    }
+  }
+  return nullptr;
+}
+
+nsIFrame* nsWindow::GetFrame() const {
+  nsView* view = nsView::GetViewFor(this);
+  if (!view) {
+    return nullptr;
+  }
+  return view->GetFrame();
+}
+
+void nsWindow::UpdateMozWindowActive() {
+  // Update activation state for the :-moz-window-inactive pseudoclass.
+  // Normally, this follows focus; we override it here to follow
+  // GDK_WINDOW_STATE_FOCUSED.
+  if (mozilla::dom::Document* document = GetDocument()) {
+    if (nsPIDOMWindowOuter* window = document->GetWindow()) {
+      if (RefPtr<mozilla::dom::BrowsingContext> bc =
+              window->GetBrowsingContext()) {
+        bc->SetIsActiveBrowserWindow(!mTitlebarBackdropState);
+      }
+    }
+  }
+}
+
+void nsWindow::ForceTitlebarRedraw() {
+  MOZ_ASSERT(mDrawInTitlebar, "We should not redraw invisible titlebar.");
+
+  if (!mWidgetListener || !mWidgetListener->GetPresShell()) {
+    return;
+  }
+
+  nsIFrame* frame = GetFrame();
+  if (!frame) {
+    return;
+  }
+
+  frame = FindTitlebarFrame(frame);
+  if (frame) {
+    nsIContent* content = frame->GetContent();
+    if (content) {
+      nsLayoutUtils::PostRestyleEvent(content->AsElement(), RestyleHint{0},
+                                      nsChangeHint_RepaintFrame);
+    }
+  }
+}
+
+void nsWindow::LockAspectRatio(bool aShouldLock) {
+  if (!gUseAspectRatio) {
+    return;
+  }
+
+  if (aShouldLock) {
+    int decWidth = 0, decHeight = 0;
+    AddCSDDecorationSize(&decWidth, &decHeight);
+
+    float width =
+        DevicePixelsToGdkCoordRoundDown(mLastSizeRequest.width) + decWidth;
+    float height =
+        DevicePixelsToGdkCoordRoundDown(mLastSizeRequest.height) + decHeight;
+
+    mAspectRatio = width / height;
+    LOG("nsWindow::LockAspectRatio() width %f height %f aspect %f", width,
+        height, mAspectRatio);
+  } else {
+    mAspectRatio = 0.0;
+    LOG("nsWindow::LockAspectRatio() removed aspect ratio");
+  }
+
+  ApplySizeConstraints();
+}
+
+nsWindow* nsWindow::GetFocusedWindow() { return gFocusWindow; }
+
+#ifdef MOZ_WAYLAND
+bool nsWindow::SetEGLNativeWindowSize(
+    const LayoutDeviceIntSize& aEGLWindowSize) {
+  if (!GdkIsWaylandDisplay()) {
+    return true;
+  }
+
+  // SetEGLNativeWindowSize() is called from renderer/compositor thread,
+  // make sure nsWindow is not destroyed.
+  bool paint = false;
+
+  // See NS_NATIVE_EGL_WINDOW why we can't block here.
+  if (mDestroyMutex.TryLock()) {
+    if (!mIsDestroyed) {
+      gint scale = GdkCeiledScaleFactor();
+#  ifdef MOZ_LOGGING
+      if (LOG_ENABLED()) {
+        static uintptr_t lastSizeLog = 0;
+        uintptr_t sizeLog = uintptr_t(this) + aEGLWindowSize.width +
+                            aEGLWindowSize.height + scale +
+                            aEGLWindowSize.width / scale +
+                            aEGLWindowSize.height / scale;
+        if (lastSizeLog != sizeLog) {
+          lastSizeLog = sizeLog;
+          LOG("nsWindow::SetEGLNativeWindowSize() %d x %d scale %d (unscaled "
+              "%d x "
+              "%d)",
+              aEGLWindowSize.width, aEGLWindowSize.height, scale,
+              aEGLWindowSize.width / scale, aEGLWindowSize.height / scale);
+        }
+      }
+#  endif
+      paint = moz_container_wayland_egl_window_set_size(
+          mContainer, aEGLWindowSize.ToUnknownSize(), scale);
+    }
+    mDestroyMutex.Unlock();
+  }
+  return paint;
+}
+#endif
+
+nsWindow* nsWindow::GetWindow(GdkWindow* window) {
+  return get_window_for_gdk_window(window);
+}
+
+void nsWindow::ClearRenderingQueue() {
+  LOG("nsWindow::ClearRenderingQueue()");
+
+  if (mWidgetListener) {
+    mWidgetListener->RequestWindowClose(this);
+  }
+  DestroyLayerManager();
+}
+
+void nsWindow::DisableRendering() {
+  LOG("nsWindow::DisableRendering()");
+
+  if (mGdkWindow) {
+    if (mIMContext) {
+      mIMContext->SetGdkWindow(nullptr);
+    }
+    g_object_set_data(G_OBJECT(mGdkWindow), "nsWindow", nullptr);
+    mGdkWindow = nullptr;
+  }
+
+#ifdef MOZ_WAYLAND
+  // Widget is backed by OpenGL EGLSurface created over wl_surface
+  // owned by mContainer.
+  // RenderCompositorEGL::Resume() deletes recent EGLSurface based on
+  // wl_surface owned by mContainer and creates a new fallback EGLSurface.
+  // Then we can delete wl_surface in moz_container_wayland_unmap().
+  // We don't want to pause compositor as it may lead to whole
+  // browser freeze (Bug 1777664).
+  ///
+  // We don't need to do such operation for SW backend as
+  // WindowSurfaceWaylandMB::Commit() gets wl_surface from
+  // MozContainer every commit.
+  if (moz_container_wayland_has_egl_window(mContainer) &&
+      mCompositorWidgetDelegate) {
+    if (CompositorBridgeChild* remoteRenderer = GetRemoteRenderer()) {
+      // Call DisableRendering() to make GtkCompositorWidget hidden.
+      // Then SendResume() will create fallback EGLSurface, see
+      // GLContextEGL::CreateEGLSurfaceForCompositorWidget().
+      mCompositorWidgetDelegate->DisableRendering();
+      remoteRenderer->SendResume();
+      mCompositorWidgetDelegate->EnableRendering(GetX11Window(),
+                                                 GetShapedState());
+    }
+  }
+#endif
+}
+
+// Apply workaround for Mutter compositor bug (mzbz#1777269).
+//
+// When we open a popup window (tooltip for instance) attached to
+// GDK_WINDOW_TYPE_HINT_UTILITY parent popup, Mutter compositor sends bogus
+// leave/enter events to the GDK_WINDOW_TYPE_HINT_UTILITY popup.
+// That leads to immediate tooltip close. As a workaround ignore these
+// bogus events.
+//
+// We need to check two affected window types:
+//
+// - toplevel window with at least two child popups where the first one is
+//   GDK_WINDOW_TYPE_HINT_UTILITY.
+// - GDK_WINDOW_TYPE_HINT_UTILITY popup with a child popup
+//
+// We need to mask two bogus leave/enter sequences:
+//  1) Leave (popup) -> Enter (toplevel)
+//  2) Leave (toplevel) -> Enter (popup)
+//
+// TODO: persistent (non-tracked) popups with tooltip/child popups?
+//
+bool nsWindow::ApplyEnterLeaveMutterWorkaround() {
+  // Leave (toplevel) case
+  if (mWindowType == WindowType::TopLevel && mWaylandPopupNext &&
+      mWaylandPopupNext->mWaylandPopupNext &&
+      gtk_window_get_type_hint(GTK_WINDOW(mWaylandPopupNext->GetGtkWidget())) ==
+          GDK_WINDOW_TYPE_HINT_UTILITY) {
+    LOG("nsWindow::ApplyEnterLeaveMutterWorkaround(): leave toplevel");
+    return true;
+  }
+  // Leave (popup) case
+  if (IsWaylandPopup() && mWaylandPopupNext &&
+      gtk_window_get_type_hint(GTK_WINDOW(mShell)) ==
+          GDK_WINDOW_TYPE_HINT_UTILITY) {
+    LOG("nsWindow::ApplyEnterLeaveMutterWorkaround(): leave popup");
+    return true;
+  }
+  return false;
+}
+
+void nsWindow::NotifyOcclusionState(OcclusionState aState) {
+  if (!IsTopLevelWindowType()) {
+    return;
+  }
+
+  bool isFullyOccluded = aState == OcclusionState::OCCLUDED;
+  if (mIsFullyOccluded == isFullyOccluded) {
+    return;
+  }
+  mIsFullyOccluded = isFullyOccluded;
+
+  LOG("nsWindow::NotifyOcclusionState() mIsFullyOccluded %d", mIsFullyOccluded);
+  if (mWidgetListener) {
+    mWidgetListener->OcclusionStateChanged(mIsFullyOccluded);
+  }
+}
+
+void nsWindow::SetDragSource(GdkDragContext* aSourceDragContext) {
+  mSourceDragContext = aSourceDragContext;
+  if (IsPopup() &&
+      (widget::GdkIsWaylandDisplay() || widget::IsXWaylandProtocol())) {
+    if (auto* menuPopupFrame = GetMenuPopupFrame(GetFrame())) {
+      menuPopupFrame->SetIsDragSource(!!aSourceDragContext);
+    }
+  }
+}
diff --git a/widget/gtk/nsWindow.h b/widget/gtk/nsWindow.h
new file mode 100644
index 0000000000..e235d12c08
--- /dev/null
+++ b/widget/gtk/nsWindow.h
@@ -0,0 +1,1016 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsWindow_h__
+#define __nsWindow_h__
+
+#include <gdk/gdk.h>
+#include <gtk/gtk.h>
+
+#include "CompositorWidget.h"
+#include "MozContainer.h"
+#include "VsyncSource.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/TouchEvents.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/widget/WindowSurface.h"
+#include "mozilla/widget/WindowSurfaceProvider.h"
+#include "nsBaseWidget.h"
+#include "nsGkAtoms.h"
+#include "nsIDragService.h"
+#include "nsRefPtrHashtable.h"
+#include "IMContextWrapper.h"
+#include "LookAndFeel.h"
+
+#ifdef ACCESSIBILITY
+#  include "mozilla/a11y/LocalAccessible.h"
+#endif
+
+#ifdef MOZ_X11
+#  include <gdk/gdkx.h>
+#  include "X11UndefineNone.h"
+#endif
+#ifdef MOZ_WAYLAND
+#  include <gdk/gdkwayland.h>
+#  include "base/thread.h"
+#  include "WaylandVsyncSource.h"
+#  include "nsClipboardWayland.h"
+#endif
+
+#ifdef MOZ_LOGGING
+
+#  include "mozilla/Logging.h"
+#  include "nsTArray.h"
+#  include "Units.h"
+
+extern mozilla::LazyLogModule gWidgetLog;
+extern mozilla::LazyLogModule gWidgetDragLog;
+extern mozilla::LazyLogModule gWidgetPopupLog;
+extern mozilla::LazyLogModule gWidgetVsync;
+
+#  define LOG(str, ...)                               \
+    MOZ_LOG(IsPopup() ? gWidgetPopupLog : gWidgetLog, \
+            mozilla::LogLevel::Debug,                 \
+            ("%s: " str, GetDebugTag().get(), ##__VA_ARGS__))
+#  define LOGW(...) MOZ_LOG(gWidgetLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#  define LOGDRAG(...) \
+    MOZ_LOG(gWidgetDragLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#  define LOG_POPUP(...) \
+    MOZ_LOG(gWidgetPopupLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#  define LOG_VSYNC(...) \
+    MOZ_LOG(gWidgetVsync, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#  define LOG_ENABLED()                                         \
+    (MOZ_LOG_TEST(gWidgetPopupLog, mozilla::LogLevel::Debug) || \
+     MOZ_LOG_TEST(gWidgetLog, mozilla::LogLevel::Debug))
+
+#else
+
+#  define LOG(...)
+#  define LOGW(...)
+#  define LOGDRAG(...)
+#  define LOG_POPUP(...)
+#  define LOG_ENABLED() false
+
+#endif /* MOZ_LOGGING */
+
+#if defined(MOZ_WAYLAND) && !defined(MOZ_X11)
+typedef uintptr_t Window;
+#endif
+
+class gfxPattern;
+class nsIFrame;
+#if !GTK_CHECK_VERSION(3, 18, 0)
+struct _GdkEventTouchpadPinch;
+typedef struct _GdkEventTouchpadPinch GdkEventTouchpadPinch;
+#endif
+
+#if !GTK_CHECK_VERSION(3, 22, 0)
+typedef enum {
+  GDK_ANCHOR_FLIP_X = 1 << 0,
+  GDK_ANCHOR_FLIP_Y = 1 << 1,
+  GDK_ANCHOR_SLIDE_X = 1 << 2,
+  GDK_ANCHOR_SLIDE_Y = 1 << 3,
+  GDK_ANCHOR_RESIZE_X = 1 << 4,
+  GDK_ANCHOR_RESIZE_Y = 1 << 5,
+  GDK_ANCHOR_FLIP = GDK_ANCHOR_FLIP_X | GDK_ANCHOR_FLIP_Y,
+  GDK_ANCHOR_SLIDE = GDK_ANCHOR_SLIDE_X | GDK_ANCHOR_SLIDE_Y,
+  GDK_ANCHOR_RESIZE = GDK_ANCHOR_RESIZE_X | GDK_ANCHOR_RESIZE_Y
+} GdkAnchorHints;
+#endif
+
+namespace mozilla {
+enum class NativeKeyBindingsType : uint8_t;
+
+class TimeStamp;
+#ifdef MOZ_X11
+class CurrentX11TimeGetter;
+#endif
+
+namespace widget {
+class Screen;
+}  // namespace widget
+}  // namespace mozilla
+
+class nsWindow final : public nsBaseWidget {
+ public:
+  typedef mozilla::gfx::DrawTarget DrawTarget;
+  typedef mozilla::WidgetEventTime WidgetEventTime;
+  typedef mozilla::WidgetKeyboardEvent WidgetKeyboardEvent;
+  typedef mozilla::widget::PlatformCompositorWidgetDelegate
+      PlatformCompositorWidgetDelegate;
+
+  nsWindow();
+
+  static void ReleaseGlobals();
+
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(nsWindow, nsBaseWidget)
+
+  nsresult DispatchEvent(mozilla::WidgetGUIEvent* aEvent,
+                         nsEventStatus& aStatus) override;
+
+  // called when we are destroyed
+  void OnDestroy() override;
+
+  // called to check and see if a widget's dimensions are sane
+  bool AreBoundsSane(void);
+
+  // nsIWidget
+  using nsBaseWidget::Create;  // for Create signature not overridden here
+  [[nodiscard]] nsresult Create(nsIWidget* aParent,
+                                nsNativeWidget aNativeParent,
+                                const LayoutDeviceIntRect& aRect,
+                                InitData* aInitData) override;
+  void Destroy() override;
+  nsIWidget* GetParent() override;
+  float GetDPI() override;
+  double GetDefaultScaleInternal() override;
+  mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale() override;
+  mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScaleByScreen()
+      override;
+  void SetParent(nsIWidget* aNewParent) override;
+  void SetModal(bool aModal) override;
+  bool IsVisible() const override;
+  bool IsMapped() const override;
+  void ConstrainPosition(DesktopIntPoint&) override;
+  void SetSizeConstraints(const SizeConstraints& aConstraints) override;
+  void LockAspectRatio(bool aShouldLock) override;
+  void Move(double aX, double aY) override;
+  void Show(bool aState) override;
+  void Resize(double aWidth, double aHeight, bool aRepaint) override;
+  void Resize(double aX, double aY, double aWidth, double aHeight,
+              bool aRepaint) override;
+  bool IsEnabled() const override;
+
+  void SetZIndex(int32_t aZIndex) override;
+  nsSizeMode SizeMode() override { return mSizeMode; }
+  void SetSizeMode(nsSizeMode aMode) override;
+  void GetWorkspaceID(nsAString& workspaceID) override;
+  void MoveToWorkspace(const nsAString& workspaceID) override;
+  void Enable(bool aState) override;
+  void SetFocus(Raise, mozilla::dom::CallerType aCallerType) override;
+  LayoutDeviceIntRect GetScreenBounds() override;
+  LayoutDeviceIntRect GetClientBounds() override;
+  LayoutDeviceIntSize GetClientSize() override;
+  LayoutDeviceIntPoint GetClientOffset() override { return mClientOffset; }
+  LayoutDeviceIntPoint GetScreenEdgeSlop() override;
+
+  // Recomputes the client offset according to our current window position.
+  // If aNotify is true, NotifyWindowMoved will be called on client offset
+  // changes.
+  //
+  // NOTE(emilio): It seems that as long any change here update either the size
+  // or the position of the window, we should be doing fine without notifying,
+  // but this is done to preserve existing behavior.
+  void RecomputeClientOffset(bool aNotify);
+
+  void SetCursor(const Cursor&) override;
+  void Invalidate(const LayoutDeviceIntRect& aRect) override;
+  void* GetNativeData(uint32_t aDataType) override;
+  nsresult SetTitle(const nsAString& aTitle) override;
+  void SetIcon(const nsAString& aIconSpec) override;
+  void SetWindowClass(const nsAString& xulWinType, const nsAString& xulWinClass,
+                      const nsAString& xulWinName) override;
+  LayoutDeviceIntPoint WidgetToScreenOffset() override;
+  void CaptureRollupEvents(bool aDoCapture) override;
+  [[nodiscard]] nsresult GetAttention(int32_t aCycleCount) override;
+  bool HasPendingInputEvent() override;
+
+  bool PrepareForFullscreenTransition(nsISupports** aData) override;
+  void PerformFullscreenTransition(FullscreenTransitionStage aStage,
+                                   uint16_t aDuration, nsISupports* aData,
+                                   nsIRunnable* aCallback) override;
+  already_AddRefed<Screen> GetWidgetScreen() override;
+  nsresult MakeFullScreen(bool aFullScreen) override;
+  void HideWindowChrome(bool aShouldHide) override;
+
+  /**
+   * GetLastUserInputTime returns a timestamp for the most recent user input
+   * event.  This is intended for pointer grab requests (including drags).
+   */
+  static guint32 GetLastUserInputTime();
+
+  // utility method, -1 if no change should be made, otherwise returns a
+  // value that can be passed to gdk_window_set_decorations
+  gint ConvertBorderStyles(BorderStyle aStyle);
+
+  mozilla::widget::IMContextWrapper* GetIMContext() const { return mIMContext; }
+
+  bool DispatchCommandEvent(nsAtom* aCommand);
+  bool DispatchContentCommandEvent(mozilla::EventMessage aMsg);
+
+  // event callbacks
+  gboolean OnExposeEvent(cairo_t* cr);
+  gboolean OnConfigureEvent(GtkWidget* aWidget, GdkEventConfigure* aEvent);
+  void OnMap();
+  void OnUnmap();
+  void OnSizeAllocate(GtkAllocation* aAllocation);
+  void OnDeleteEvent();
+  void OnEnterNotifyEvent(GdkEventCrossing* aEvent);
+  void OnLeaveNotifyEvent(GdkEventCrossing* aEvent);
+  void OnMotionNotifyEvent(GdkEventMotion* aEvent);
+  void OnButtonPressEvent(GdkEventButton* aEvent);
+  void OnButtonReleaseEvent(GdkEventButton* aEvent);
+  void OnContainerFocusInEvent(GdkEventFocus* aEvent);
+  void OnContainerFocusOutEvent(GdkEventFocus* aEvent);
+  gboolean OnKeyPressEvent(GdkEventKey* aEvent);
+  gboolean OnKeyReleaseEvent(GdkEventKey* aEvent);
+
+  void OnScrollEvent(GdkEventScroll* aEvent);
+
+  void OnVisibilityNotifyEvent(GdkVisibilityState aState);
+  void OnWindowStateEvent(GtkWidget* aWidget, GdkEventWindowState* aEvent);
+  void OnDragDataReceivedEvent(GtkWidget* aWidget, GdkDragContext* aDragContext,
+                               gint aX, gint aY,
+                               GtkSelectionData* aSelectionData, guint aInfo,
+                               guint aTime, gpointer aData);
+  gboolean OnPropertyNotifyEvent(GtkWidget* aWidget, GdkEventProperty* aEvent);
+  gboolean OnTouchEvent(GdkEventTouch* aEvent);
+  gboolean OnTouchpadPinchEvent(GdkEventTouchpadPinch* aEvent);
+
+  gint GetInputRegionMarginInGdkCoords();
+
+  void UpdateTopLevelOpaqueRegion();
+
+  already_AddRefed<mozilla::gfx::DrawTarget> StartRemoteDrawingInRegion(
+      const LayoutDeviceIntRegion& aInvalidRegion,
+      mozilla::layers::BufferMode* aBufferMode) override;
+  void EndRemoteDrawingInRegion(
+      mozilla::gfx::DrawTarget* aDrawTarget,
+      const LayoutDeviceIntRegion& aInvalidRegion) override;
+
+  void SetProgress(unsigned long progressPercent);
+
+  RefPtr<mozilla::VsyncDispatcher> GetVsyncDispatcher() override;
+  bool SynchronouslyRepaintOnResize() override;
+
+  void OnDPIChanged();
+  void OnCheckResize();
+  void OnCompositedChanged();
+  void OnScaleChanged(bool aNotify);
+  void DispatchResized();
+
+  static guint32 sLastButtonPressTime;
+
+  MozContainer* GetMozContainer() { return mContainer; }
+  GdkWindow* GetGdkWindow() const { return mGdkWindow; };
+  GdkWindow* GetToplevelGdkWindow() const;
+  GtkWidget* GetGtkWidget() const { return mShell; }
+  nsIFrame* GetFrame() const;
+  nsWindow* GetEffectiveParent();
+  bool IsDestroyed() const { return mIsDestroyed; }
+  bool IsPopup() const;
+  bool IsWaylandPopup() const;
+  bool IsDragPopup() { return mIsDragPopup; };
+
+  nsAutoCString GetDebugTag() const;
+
+  void DispatchDragEvent(mozilla::EventMessage aMsg,
+                         const LayoutDeviceIntPoint& aRefPoint, guint aTime);
+  static void UpdateDragStatus(GdkDragContext* aDragContext,
+                               nsIDragService* aDragService);
+  void SetDragSource(GdkDragContext* aSourceDragContext);
+
+  WidgetEventTime GetWidgetEventTime(guint32 aEventTime);
+  mozilla::TimeStamp GetEventTimeStamp(guint32 aEventTime);
+#ifdef MOZ_X11
+  mozilla::CurrentX11TimeGetter* GetCurrentTimeGetter();
+#endif
+
+  void SetInputContext(const InputContext& aContext,
+                       const InputContextAction& aAction) override;
+  InputContext GetInputContext() override;
+  TextEventDispatcherListener* GetNativeTextEventDispatcherListener() override;
+  MOZ_CAN_RUN_SCRIPT bool GetEditCommands(
+      mozilla::NativeKeyBindingsType aType,
+      const mozilla::WidgetKeyboardEvent& aEvent,
+      nsTArray<mozilla::CommandInt>& aCommands) override;
+
+  // These methods are for toplevel windows only.
+  void ResizeTransparencyBitmap();
+  void ApplyTransparencyBitmap();
+  void ClearTransparencyBitmap();
+
+  void SetTransparencyMode(TransparencyMode aMode) override;
+  TransparencyMode GetTransparencyMode() override;
+  void SetInputRegion(const InputRegion&) override;
+  nsresult UpdateTranslucentWindowAlphaInternal(const nsIntRect& aRect,
+                                                uint8_t* aAlphas,
+                                                int32_t aStride);
+  void ReparentNativeWidget(nsIWidget* aNewParent) override;
+
+  void UpdateTitlebarTransparencyBitmap();
+
+  nsresult SynthesizeNativeMouseEvent(LayoutDeviceIntPoint aPoint,
+                                      NativeMouseMessage aNativeMessage,
+                                      mozilla::MouseButton aButton,
+                                      nsIWidget::Modifiers aModifierFlags,
+                                      nsIObserver* aObserver) override;
+
+  nsresult SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
+                                     nsIObserver* aObserver) override {
+    return SynthesizeNativeMouseEvent(
+        aPoint, NativeMouseMessage::Move, mozilla::MouseButton::eNotPressed,
+        nsIWidget::Modifiers::NO_MODIFIERS, aObserver);
+  }
+
+  nsresult SynthesizeNativeMouseScrollEvent(
+      LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage, double aDeltaX,
+      double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+      uint32_t aAdditionalFlags, nsIObserver* aObserver) override;
+
+  nsresult SynthesizeNativeTouchPoint(uint32_t aPointerId,
+                                      TouchPointerState aPointerState,
+                                      LayoutDeviceIntPoint aPoint,
+                                      double aPointerPressure,
+                                      uint32_t aPointerOrientation,
+                                      nsIObserver* aObserver) override;
+
+  nsresult SynthesizeNativeTouchPadPinch(TouchpadGesturePhase aEventPhase,
+                                         float aScale,
+                                         LayoutDeviceIntPoint aPoint,
+                                         int32_t aModifierFlags) override;
+
+  nsresult SynthesizeNativeTouchpadPan(TouchpadGesturePhase aEventPhase,
+                                       LayoutDeviceIntPoint aPoint,
+                                       double aDeltaX, double aDeltaY,
+                                       int32_t aModifierFlags,
+                                       nsIObserver* aObserver) override;
+
+  void GetCompositorWidgetInitData(
+      mozilla::widget::CompositorWidgetInitData* aInitData) override;
+
+  nsresult SetNonClientMargins(const LayoutDeviceIntMargin&) override;
+  void SetDrawsInTitlebar(bool aState);
+  void SetTitlebarRect();
+  mozilla::LayoutDeviceIntCoord GetTitlebarRadius();
+  LayoutDeviceIntRect GetTitlebarRect();
+  void UpdateWindowDraggingRegion(
+      const LayoutDeviceIntRegion& aRegion) override;
+
+  // HiDPI scale conversion
+  gint GdkCeiledScaleFactor();
+  double FractionalScaleFactor();
+
+  // To GDK
+  gint DevicePixelsToGdkCoordRoundUp(int);
+  gint DevicePixelsToGdkCoordRoundDown(int);
+  GdkPoint DevicePixelsToGdkPointRoundDown(const LayoutDeviceIntPoint&);
+  GdkRectangle DevicePixelsToGdkSizeRoundUp(const LayoutDeviceIntSize&);
+  GdkRectangle DevicePixelsToGdkRectRoundOut(const LayoutDeviceIntRect&);
+
+  // From GDK
+  int GdkCoordToDevicePixels(gint);
+  LayoutDeviceIntPoint GdkPointToDevicePixels(const GdkPoint&);
+  LayoutDeviceIntPoint GdkEventCoordsToDevicePixels(gdouble aX, gdouble aY);
+  LayoutDeviceIntRect GdkRectToDevicePixels(const GdkRectangle&);
+
+  bool WidgetTypeSupportsAcceleration() override;
+
+  nsresult SetSystemFont(const nsCString& aFontName) override;
+  nsresult GetSystemFont(nsCString& aFontName) override;
+
+  typedef enum {
+    GTK_DECORATION_SYSTEM,  // CSD including shadows
+    GTK_DECORATION_CLIENT,  // CSD without shadows
+    GTK_DECORATION_NONE,    // WM does not support CSD at all
+  } GtkWindowDecoration;
+  /**
+   * Get the support of Client Side Decoration by checking the desktop
+   * environment.
+   */
+  static GtkWindowDecoration GetSystemGtkWindowDecoration();
+
+  static bool GetTopLevelWindowActiveState(nsIFrame* aFrame);
+  static bool TitlebarUseShapeMask();
+  bool IsRemoteContent() { return HasRemoteContent(); }
+  void NativeMoveResizeWaylandPopupCallback(const GdkRectangle* aFinalSize,
+                                            bool aFlippedX, bool aFlippedY);
+  static bool IsToplevelWindowTransparent();
+
+  static nsWindow* GetFocusedWindow();
+
+#ifdef MOZ_WAYLAND
+  // Use xdg-activation protocol to transfer focus from gFocusWindow to aWindow.
+  static void TransferFocusToWaylandWindow(nsWindow* aWindow);
+  void FocusWaylandWindow(const char* aTokenID);
+
+  bool GetCSDDecorationOffset(int* aDx, int* aDy);
+  bool SetEGLNativeWindowSize(const LayoutDeviceIntSize& aEGLWindowSize);
+  void WaylandDragWorkaround(GdkEventButton* aEvent);
+
+  void CreateCompositorVsyncDispatcher() override;
+  LayoutDeviceIntPoint GetNativePointerLockCenter() {
+    return mNativePointerLockCenter;
+  }
+  void SetNativePointerLockCenter(
+      const LayoutDeviceIntPoint& aLockCenter) override;
+  void LockNativePointer() override;
+  void UnlockNativePointer() override;
+  LayoutDeviceIntSize GetMoveToRectPopupSize() const override {
+    return mMoveToRectPopupSize;
+  };
+#endif
+
+  typedef enum {
+    // WebRender compositor is enabled
+    COMPOSITOR_ENABLED,
+    // WebRender compositor is paused as we're repainting whole window and
+    // we're waiting for content process to update page content.
+    COMPOSITOR_PAUSED_FLICKERING
+  } WindowCompositorState;
+
+  // Pause compositor to avoid rendering artifacts from content process.
+  void ResumeCompositorImpl();
+  void ResumeCompositorFlickering();
+  void ResumeCompositorFromCompositorThread();
+  void PauseCompositorFlickering();
+  bool IsWaitingForCompositorResume();
+
+  // Force hide this window, remove compositor etc. to avoid
+  // rendering queue blocking (see Bug 1782948).
+  void ClearRenderingQueue();
+
+  void DisableRendering();
+
+  bool ApplyEnterLeaveMutterWorkaround();
+
+  void NotifyOcclusionState(mozilla::widget::OcclusionState aState) override;
+
+  static nsWindow* GetWindow(GdkWindow* window);
+
+ protected:
+  virtual ~nsWindow();
+
+  // event handling code
+  void DispatchActivateEvent(void);
+  void DispatchDeactivateEvent(void);
+  void MaybeDispatchResized();
+  void DispatchPanGesture(mozilla::PanGestureInput& aPanInput);
+
+  void RegisterTouchWindow() override;
+
+  nsCOMPtr<nsIWidget> mParent;
+  mozilla::Atomic<int, mozilla::Relaxed> mCeiledScaleFactor{1};
+  double mFractionalScaleFactor = 0.0;
+
+  void UpdateAlpha(mozilla::gfx::SourceSurface* aSourceSurface,
+                   nsIntRect aBoundsRect);
+
+  void NativeMoveResize(bool aMoved, bool aResized);
+
+  void NativeShow(bool aAction);
+  void SetHasMappedToplevel(bool aState);
+  LayoutDeviceIntSize GetSafeWindowSize(LayoutDeviceIntSize aSize);
+
+  void DispatchContextMenuEventFromMouseEvent(
+      uint16_t domButton, GdkEventButton* aEvent,
+      const mozilla::LayoutDeviceIntPoint& aRefPoint);
+
+  void TryToShowNativeWindowMenu(GdkEventButton* aEvent);
+
+  bool DoTitlebarAction(mozilla::LookAndFeel::TitlebarEvent aEvent,
+                        GdkEventButton* aButtonEvent);
+
+  void WaylandStartVsync();
+  void WaylandStopVsync();
+  void DestroyChildWindows();
+  GtkWidget* GetToplevelWidget() const;
+  nsWindow* GetContainerWindow() const;
+  Window GetX11Window();
+  bool GetShapedState();
+  void EnsureGdkWindow();
+  void SetUrgencyHint(GtkWidget* top_window, bool state);
+  void SetDefaultIcon(void);
+  void SetWindowDecoration(BorderStyle aStyle);
+  void InitButtonEvent(mozilla::WidgetMouseEvent& aEvent,
+                       GdkEventButton* aGdkEvent,
+                       const mozilla::LayoutDeviceIntPoint& aRefPoint);
+  bool CheckForRollup(gdouble aMouseX, gdouble aMouseY, bool aIsWheel,
+                      bool aAlwaysRollup);
+  void RollupAllMenus() { CheckForRollup(0, 0, false, true); }
+  void CheckForRollupDuringGrab() { RollupAllMenus(); }
+
+  bool GetDragInfo(mozilla::WidgetMouseEvent* aMouseEvent, GdkWindow** aWindow,
+                   gint* aButton, gint* aRootX, gint* aRootY);
+  nsIWidgetListener* GetListener();
+
+  nsWindow* GetTransientForWindowIfPopup();
+  bool IsHandlingTouchSequence(GdkEventSequence* aSequence);
+
+  void ResizeInt(const mozilla::Maybe<LayoutDeviceIntPoint>& aMove,
+                 LayoutDeviceIntSize aSize);
+  void NativeMoveResizeWaylandPopup(bool aMove, bool aResize);
+
+  // Returns a window edge if the given point (in device pixels) is within a
+  // resizer region of the window.
+  // Only used when drawing decorations client side.
+  mozilla::Maybe<GdkWindowEdge> CheckResizerEdge(const LayoutDeviceIntPoint&);
+
+  GtkTextDirection GetTextDirection();
+
+  bool DrawsToCSDTitlebar() const;
+  void AddCSDDecorationSize(int* aWidth, int* aHeight);
+
+  void CreateAndPutGdkScrollEvent(mozilla::LayoutDeviceIntPoint aPoint,
+                                  double aDeltaX, double aDeltaY);
+
+  nsCString mGtkWindowAppClass;
+  nsCString mGtkWindowAppName;
+  nsCString mGtkWindowRoleName;
+  void RefreshWindowClass();
+
+  GtkWidget* mShell = nullptr;
+  MozContainer* mContainer = nullptr;
+  GdkWindow* mGdkWindow = nullptr;
+  PlatformCompositorWidgetDelegate* mCompositorWidgetDelegate = nullptr;
+  mozilla::Atomic<WindowCompositorState, mozilla::Relaxed> mCompositorState{
+      COMPOSITOR_ENABLED};
+  // This is used in COMPOSITOR_PAUSED_FLICKERING mode only to resume compositor
+  // in some reasonable time when page content is not updated.
+  guint mCompositorPauseTimeoutID = 0;
+
+  // The actual size mode that's in effect.
+  nsSizeMode mSizeMode = nsSizeMode_Normal;
+  // The last size mode we've requested. This might not match mSizeMode if
+  // there's a request to change the size mode in progress.
+  nsSizeMode mLastSizeModeRequest = nsSizeMode_Normal;
+  nsSizeMode mLastSizeModeBeforeFullscreen = nsSizeMode_Normal;
+
+  float mAspectRatio = 0.0f;
+  float mAspectRatioSaved = 0.0f;
+  mozilla::Maybe<GtkOrientation> mAspectResizer;
+  LayoutDeviceIntPoint mLastResizePoint;
+
+  // The size requested, which might not be reflected in mBounds.  Used in
+  // WaylandPopupSetDirectPosition() to remember intended size for popup
+  // positioning, in LockAspect() to remember the intended aspect ratio, and
+  // to remember a size requested while waiting for moved-to-rect when
+  // OnSizeAllocate() might change mBounds.Size().
+  LayoutDeviceIntSize mLastSizeRequest;
+  LayoutDeviceIntPoint mClientOffset;
+  // Indicates a new size that still needs to be dispatched.
+  LayoutDeviceIntSize mNeedsDispatchSize = LayoutDeviceIntSize(-1, -1);
+
+  // This field omits duplicate scroll events caused by GNOME bug 726878.
+  guint32 mLastScrollEventTime = GDK_CURRENT_TIME;
+  mozilla::ScreenCoord mLastPinchEventSpan;
+
+  struct TouchpadPinchGestureState {
+    // Focus point of the PHASE_BEGIN event
+    ScreenPoint mBeginFocus;
+
+    // Focus point of the most recent PHASE_UPDATE event
+    ScreenPoint mCurrentFocus;
+  };
+
+  // Used for handling touchpad pinch gestures
+  ScreenPoint mCurrentTouchpadFocus;
+
+  // Used for synthesizing touchpad pinch gestures
+  TouchpadPinchGestureState mCurrentSynthesizedTouchpadPinch;
+
+  // Used for synthesizing touchpad pan gestures
+  struct TouchpadPanGestureState {
+    mozilla::Maybe<TouchpadGesturePhase> mTouchpadGesturePhase;
+    uint64_t mSavedObserver = 0;
+  };
+
+  // Used for synthesizing touchpad pan gestures
+  TouchpadPanGestureState mCurrentSynthesizedTouchpadPan;
+
+  // for touch event handling
+  nsRefPtrHashtable<nsPtrHashKey<GdkEventSequence>, mozilla::dom::Touch>
+      mTouches;
+
+  // Upper bound on pending ConfigureNotify events to be dispatched to the
+  // window. See bug 1225044.
+  unsigned int mPendingConfigures = 0;
+
+  // Window titlebar rendering mode, GTK_DECORATION_NONE if it's disabled
+  // for this window.
+  GtkWindowDecoration mGtkWindowDecoration = GTK_DECORATION_NONE;
+
+  // Draggable titlebar region maintained by UpdateWindowDraggingRegion
+  LayoutDeviceIntRegion mDraggableRegion;
+
+  // The cursor cache
+  static GdkCursor* gsGtkCursorCache[eCursorCount];
+
+  // If true, draw our own window titlebar.
+  bool mDrawInTitlebar = false;
+
+  mozilla::Mutex mTitlebarRectMutex;
+  LayoutDeviceIntRect mTitlebarRect MOZ_GUARDED_BY(mTitlebarRectMutex);
+
+  mozilla::Mutex mDestroyMutex;
+
+  // Has this widget been destroyed yet?
+  bool mIsDestroyed : 1;
+  // mIsShown tracks requested visible status from browser perspective, i.e.
+  // if the window should be visible or now.
+  bool mIsShown : 1;
+  // mNeedsShow is set when browser requested to show this window but we failed
+  // to do so for some reason (wrong window size for instance).
+  // In such case we set mIsShown = true and mNeedsShow = true to indicate
+  // that the window is not actually visible but we report to browser that
+  // it is visible (mIsShown == true).
+  bool mNeedsShow : 1;
+  // This track real window visibility from OS perspective.
+  // It's set by OnMap/OnUnmap which is based on Gtk events.
+  bool mIsMapped : 1;
+  // is this widget enabled?
+  bool mEnabled : 1;
+  // has the native window for this been created yet?
+  bool mCreated : 1;
+  // whether we handle touch event
+  bool mHandleTouchEvent : 1;
+  // true if this is a drag and drop feedback popup
+  bool mIsDragPopup : 1;
+  bool mCompositedScreen : 1;
+  bool mIsAccelerated : 1;
+  bool mWindowShouldStartDragging : 1;
+  bool mHasMappedToplevel : 1;
+  bool mRetryPointerGrab : 1;
+  bool mPanInProgress : 1;
+  // Draw titlebar with :backdrop css state (inactive/unfocused).
+  bool mTitlebarBackdropState : 1;
+  // It's child window, i.e. window which is nested in parent window.
+  // This is obsoleted and should not be used.
+  // We use GdkWindow hierarchy for such windows.
+  bool mIsChildWindow : 1;
+  bool mAlwaysOnTop : 1;
+  bool mNoAutoHide : 1;
+  bool mIsTransparent : 1;
+  // We can expect at least one size-allocate event after early resizes.
+  bool mHasReceivedSizeAllocate : 1;
+  bool mWidgetCursorLocked : 1;
+  bool mUndecorated : 1;
+
+  /*  Gkt creates popup in two incarnations - wl_subsurface and xdg_popup.
+   *  Kind of popup is choosen before GdkWindow is mapped so we can change
+   *  it only when GdkWindow is hidden.
+   *
+   *  Relevant Gtk code is at gdkwindow-wayland.c
+   *  in should_map_as_popup() and should_map_as_subsurface()
+   *
+   *  wl_subsurface:
+   *    - can't be positioned by move-to-rect
+   *    - can stand outside popup widget hierarchy (has toplevel as parent)
+   *    - don't have child popup widgets
+   *
+   *  xdg_popup:
+   *    - can be positioned by move-to-rect
+   *    - aligned in popup widget hierarchy, first one is attached to toplevel
+   *    - has child (popup) widgets
+   *
+   *  Thus we need to map Firefox popup type to desired Gtk one:
+   *
+   *  wl_subsurface:
+   *    - pernament panels
+   *
+   *  xdg_popup:
+   *    - menus
+   *    - autohide popups (hamburger menu)
+   *    - extension popups
+   *    - tooltips
+   *
+   *  We set mPopupTrackInHierarchy = false for pernament panels which
+   *  are always mapped to toplevel and painted as wl_surfaces.
+   */
+  bool mPopupTrackInHierarchy : 1;
+  bool mPopupTrackInHierarchyConfigured : 1;
+
+  /* On X11 Gtk tends to ignore window position requests when gtk_window
+   * is hidden. Save the position requests at mPopupPosition and apply
+   * when the widget is shown.
+   */
+  bool mHiddenPopupPositioned : 1;
+
+  // The transparency bitmap is used instead of ARGB visual for toplevel
+  // window to draw titlebar.
+  bool mTransparencyBitmapForTitlebar : 1;
+
+  // True when we're on compositing window manager and this
+  // window is using visual with alpha channel.
+  bool mHasAlphaVisual : 1;
+
+  // When popup is anchored, mPopupPosition is relative to its parent popup.
+  bool mPopupAnchored : 1;
+
+  // When popup is context menu.
+  bool mPopupContextMenu : 1;
+
+  // Indicates that this popup matches layout setup so we can use parent popup
+  // coordinates reliably.
+  bool mPopupMatchesLayout : 1;
+
+  /*  Indicates that popup setup was changed and
+   *  we need to recalculate popup coordinates.
+   */
+  bool mPopupChanged : 1;
+
+  // Popup is hidden only as a part of hierarchy tree update.
+  bool mPopupTemporaryHidden : 1;
+
+  // Popup is going to be closed and removed.
+  bool mPopupClosed : 1;
+
+  // Popup is positioned by gdk_window_move_to_rect()
+  bool mPopupUseMoveToRect : 1;
+
+  /* mWaitingForMoveToRectCallback is set when move-to-rect is called
+   * and we're waiting for move-to-rect callback.
+   *
+   * If another position/resize request comes between move-to-rect call and
+   * move-to-rect callback we set mMovedAfterMoveToRect/mResizedAfterMoveToRect.
+   */
+  bool mWaitingForMoveToRectCallback : 1;
+  bool mMovedAfterMoveToRect : 1;
+  bool mResizedAfterMoveToRect : 1;
+
+  // Params used for popup placemend by GdkWindowMoveToRect.
+  // When popup is only resized and not positioned,
+  // we need to reuse last GdkWindowMoveToRect params to avoid
+  // popup movement.
+  struct WaylandPopupMoveToRectParams {
+    LayoutDeviceIntRect mAnchorRect = {0, 0, 0, 0};
+    GdkGravity mAnchorRectType = GDK_GRAVITY_NORTH_WEST;
+    GdkGravity mPopupAnchorType = GDK_GRAVITY_NORTH_WEST;
+    GdkAnchorHints mHints = GDK_ANCHOR_SLIDE;
+    GdkPoint mOffset = {0, 0};
+    bool mAnchorSet = false;
+  };
+
+  WaylandPopupMoveToRectParams mPopupMoveToRectParams;
+
+  // Whether we've configured default clear color already.
+  bool mConfiguredClearColor : 1;
+  // Whether we've received a non-blank paint in which case we can reset the
+  // clear color to transparent.
+  bool mGotNonBlankPaint : 1;
+
+  // Whether we need to retry capturing the mouse because we' re not mapped yet.
+  bool mNeedsToRetryCapturingMouse : 1;
+
+  // This bitmap tracks which pixels are transparent. We don't support
+  // full translucency at this time; each pixel is either fully opaque
+  // or fully transparent.
+  gchar* mTransparencyBitmap = nullptr;
+  int32_t mTransparencyBitmapWidth = 0;
+  int32_t mTransparencyBitmapHeight = 0;
+
+  // all of our DND stuff
+  void InitDragEvent(mozilla::WidgetDragEvent& aEvent);
+
+  float mLastMotionPressure = 0.0f;
+
+  InputRegion mInputRegion;
+
+  static bool DragInProgress(void);
+
+  void DispatchMissedButtonReleases(GdkEventCrossing* aGdkEvent);
+
+  // When window widget gets mapped/unmapped we need to configure
+  // underlying GdkWindow properly. Otherwise we'll end up with
+  // rendering to released window.
+  void ConfigureGdkWindow();
+  void ReleaseGdkWindow();
+  void ConfigureCompositor();
+
+  bool IsAlwaysUndecoratedWindow() const;
+
+  // nsBaseWidget
+  WindowRenderer* GetWindowRenderer() override;
+  void DidGetNonBlankPaint() override;
+
+  void SetCompositorWidgetDelegate(CompositorWidgetDelegate* delegate) override;
+
+  int32_t RoundsWidgetCoordinatesTo() override;
+
+  void UpdateMozWindowActive();
+
+  void ForceTitlebarRedraw();
+  bool DoDrawTilebarCorners();
+  bool IsChromeWindowTitlebar();
+
+  void SetPopupWindowDecoration(bool aShowOnTaskbar);
+
+  void ApplySizeConstraints();
+
+  // Wayland Popup section
+  GdkPoint WaylandGetParentPosition();
+  bool WaylandPopupConfigure();
+  bool WaylandPopupIsAnchored();
+  bool WaylandPopupIsMenu();
+  bool WaylandPopupIsContextMenu();
+  bool WaylandPopupIsPermanent();
+  // First popup means it's attached directly to toplevel window
+  bool WaylandPopupIsFirst();
+  bool IsWidgetOverflowWindow();
+  void RemovePopupFromHierarchyList();
+  void ShowWaylandPopupWindow();
+  void HideWaylandPopupWindow(bool aTemporaryHidden, bool aRemoveFromPopupList);
+  void ShowWaylandToplevelWindow();
+  void HideWaylandToplevelWindow();
+  void WaylandPopupHideTooltips();
+  void WaylandPopupCloseOrphanedPopups();
+  void AppendPopupToHierarchyList(nsWindow* aToplevelWindow);
+  void WaylandPopupHierarchyHideTemporary();
+  void WaylandPopupHierarchyShowTemporaryHidden();
+  void WaylandPopupHierarchyCalculatePositions();
+  bool IsInPopupHierarchy();
+  void AddWindowToPopupHierarchy();
+  void UpdateWaylandPopupHierarchy();
+  void WaylandPopupHierarchyHideByLayout(
+      nsTArray<nsIWidget*>* aLayoutWidgetHierarchy);
+  void WaylandPopupHierarchyValidateByLayout(
+      nsTArray<nsIWidget*>* aLayoutWidgetHierarchy);
+  void CloseAllPopupsBeforeRemotePopup();
+  void WaylandPopupHideClosedPopups();
+  void WaylandPopupPrepareForMove();
+  void WaylandPopupMoveImpl();
+  void WaylandPopupMovePlain(int aX, int aY);
+  bool WaylandPopupRemoveNegativePosition(int* aX = nullptr, int* aY = nullptr);
+  bool WaylandPopupCheckAndGetAnchor(GdkRectangle* aPopupAnchor,
+                                     GdkPoint* aOffset);
+  bool WaylandPopupAnchorAdjustForParentPopup(GdkRectangle* aPopupAnchor,
+                                              GdkPoint* aOffset);
+  nsWindow* GetTopmostWindow();
+  bool IsPopupInLayoutPopupChain(nsTArray<nsIWidget*>* aLayoutWidgetHierarchy,
+                                 bool aMustMatchParent);
+  void WaylandPopupMarkAsClosed();
+  void WaylandPopupRemoveClosedPopups();
+  void WaylandPopupSetDirectPosition();
+  bool WaylandPopupFitsToplevelWindow(bool aMove);
+  const WaylandPopupMoveToRectParams WaylandPopupGetPositionFromLayout();
+  void WaylandPopupPropagateChangesToLayout(bool aMove, bool aResize);
+  nsWindow* WaylandPopupFindLast(nsWindow* aPopup);
+  GtkWindow* GetCurrentTopmostWindow() const;
+  nsAutoCString GetFrameTag() const;
+  nsCString GetPopupTypeName();
+  bool IsPopupDirectionRTL();
+
+#ifdef MOZ_LOGGING
+  void LogPopupHierarchy();
+  void LogPopupAnchorHints(int aHints);
+  void LogPopupGravity(GdkGravity aGravity);
+#endif
+
+  bool IsTopLevelWindowType() const {
+    return mWindowType == WindowType::TopLevel ||
+           mWindowType == WindowType::Dialog;
+  }
+
+  // mPopupPosition is the original popup position/size from layout, set by
+  // nsWindow::Move() or nsWindow::Resize().
+  // Popup position is relative to main (toplevel) window.
+  GdkPoint mPopupPosition{};
+
+  // mRelativePopupPosition is popup position calculated against
+  // recent popup parent window.
+  GdkPoint mRelativePopupPosition{};
+
+  // Toplevel window (first element) of linked list of Wayland popups. It's null
+  // if we're the toplevel.
+  RefPtr<nsWindow> mWaylandToplevel;
+
+  // Next/Previous popups in Wayland popup hierarchy.
+  RefPtr<nsWindow> mWaylandPopupNext;
+  RefPtr<nsWindow> mWaylandPopupPrev;
+
+  // When popup is resized by Gtk by move-to-rect callback,
+  // we store final popup size here. Then we use mMoveToRectPopupSize size
+  // in following popup operations unless mLayoutPopupSizeCleared is set.
+  LayoutDeviceIntSize mMoveToRectPopupSize;
+
+  /**
+   * |mIMContext| takes all IME related stuff.
+   *
+   * This is owned by the top-level nsWindow or the topmost child
+   * nsWindow embedded in a non-Gecko widget.
+   *
+   * The instance is created when the top level widget is created.  And when
+   * the widget is destroyed, it's released.  All child windows refer its
+   * ancestor widget's instance.  So, one set of IM contexts is created for
+   * all windows in a hierarchy.  If the children are released after the top
+   * level window is released, the children still have a valid pointer,
+   * however, IME doesn't work at that time.
+   */
+  RefPtr<mozilla::widget::IMContextWrapper> mIMContext;
+
+#ifdef MOZ_X11
+  mozilla::UniquePtr<mozilla::CurrentX11TimeGetter> mCurrentTimeGetter;
+#endif
+  static GtkWindowDecoration sGtkWindowDecoration;
+
+  static bool sTransparentMainWindow;
+
+#ifdef ACCESSIBILITY
+  RefPtr<mozilla::a11y::LocalAccessible> mRootAccessible;
+
+  /**
+   * Request to create the accessible for this window if it is top level.
+   */
+  void CreateRootAccessible();
+
+  /**
+   * Dispatch accessible event for the top level window accessible.
+   *
+   * @param  aEventType  [in] the accessible event type to dispatch
+   */
+  void DispatchEventToRootAccessible(uint32_t aEventType);
+
+  /**
+   * Dispatch accessible window activate event for the top level window
+   * accessible.
+   */
+  void DispatchActivateEventAccessible();
+
+  /**
+   * Dispatch accessible window deactivate event for the top level window
+   * accessible.
+   */
+  void DispatchDeactivateEventAccessible();
+
+  /**
+   * Dispatch accessible window maximize event for the top level window
+   * accessible.
+   */
+  void DispatchMaximizeEventAccessible();
+
+  /**
+   * Dispatch accessible window minize event for the top level window
+   * accessible.
+   */
+  void DispatchMinimizeEventAccessible();
+
+  /**
+   * Dispatch accessible window restore event for the top level window
+   * accessible.
+   */
+  void DispatchRestoreEventAccessible();
+#endif
+
+  void SetUserTimeAndStartupTokenForActivatedWindow();
+
+  void KioskLockOnMonitor();
+
+  void EmulateResizeDrag(GdkEventMotion* aEvent);
+
+  void RequestRepaint(LayoutDeviceIntRegion& aRepaintRegion);
+
+#ifdef MOZ_X11
+  typedef enum {GTK_WIDGET_COMPOSIDED_DEFAULT = 0,
+                GTK_WIDGET_COMPOSIDED_DISABLED = 1,
+                GTK_WIDGET_COMPOSIDED_ENABLED = 2} WindowComposeRequest;
+  void SetCompositorHint(WindowComposeRequest aState);
+  bool ConfigureX11GLVisual();
+#endif
+#ifdef MOZ_WAYLAND
+  RefPtr<mozilla::WaylandVsyncSource> mWaylandVsyncSource;
+  RefPtr<mozilla::VsyncDispatcher> mWaylandVsyncDispatcher;
+  LayoutDeviceIntPoint mNativePointerLockCenter;
+  zwp_locked_pointer_v1* mLockedPointer = nullptr;
+  zwp_relative_pointer_v1* mRelativePointer = nullptr;
+#endif
+  // An activation token from our environment (see handling of the
+  // XDG_ACTIVATION_TOKEN/DESKTOP_STARTUP_ID) env vars.
+  nsCString mWindowActivationTokenFromEnv;
+  mozilla::widget::WindowSurfaceProvider mSurfaceProvider;
+  GdkDragContext* mSourceDragContext = nullptr;
+#if MOZ_LOGGING
+  LayoutDeviceIntRect mLastLoggedBoundSize;
+  int mLastLoggedScale = -1;
+#endif
+  // Running in kiosk mode and requested to stay on specified monitor.
+  // If monitor is removed minimize the window.
+  mozilla::Maybe<int> mKioskMonitor;
+};
+
+#endif /* __nsWindow_h__ */
diff --git a/widget/gtk/v4l2test/moz.build b/widget/gtk/v4l2test/moz.build
new file mode 100644
index 0000000000..da22288f17
--- /dev/null
+++ b/widget/gtk/v4l2test/moz.build
@@ -0,0 +1,17 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Toolkit", "Startup and Profile System")
+
+Program("v4l2test")
+SOURCES += [
+    "v4l2test.cpp",
+]
+CXXFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
+CXXFLAGS += CONFIG["MOZ_PANGO_CFLAGS"]
+OS_LIBS += CONFIG["MOZ_X11_LIBS"]
+OS_LIBS += CONFIG["MOZ_GTK3_LIBS"]
diff --git a/widget/gtk/v4l2test/v4l2test.cpp b/widget/gtk/v4l2test/v4l2test.cpp
new file mode 100644
index 0000000000..6ee685d9ed
--- /dev/null
+++ b/widget/gtk/v4l2test/v4l2test.cpp
@@ -0,0 +1,188 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <cstdio>
+#include <cstdlib>
+#include <errno.h>
+#include <fcntl.h>
+#if defined(__NetBSD__) || defined(__OpenBSD__)
+#  include <sys/videoio.h>
+#elif defined(__sun)
+#  include <sys/videodev2.h>
+#else
+#  include <linux/videodev2.h>
+#endif
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <string.h>
+#include <getopt.h>
+#include <stdint.h>
+#include <stdarg.h>
+
+#if defined(MOZ_ASAN) || defined(FUZZING)
+#  include <signal.h>
+#endif
+
+#include "mozilla/ScopeExit.h"
+
+#ifdef __SUNPRO_CC
+#  include <stdio.h>
+#endif
+
+#include "mozilla/GfxInfoUtils.h"
+
+// Print test results to stdout and logging to stderr
+#define OUTPUT_PIPE 1
+
+// Convert an integer pixfmt to a 4-character string.  str must have a length
+// of at least 5 to include null-termination.
+static void v4l2_pixfmt_to_str(uint32_t pixfmt, char* str) {
+  for (int i = 0; i < 4; i++) {
+    str[i] = (pixfmt >> (i * 8)) & 0xff;
+  }
+  str[4] = 0;
+}
+
+// Enumerate the buffer formats supported on a V4L2 buffer queue.  aTypeStr
+// is the queue type, i.e. CAPTURE or OUTPUT.
+static void v4l2_enumfmt(int aFd, int aType, const char* aTypeStr) {
+  struct v4l2_fmtdesc fmt {};
+  char pix_fmt_str[5];
+  fmt.type = aType;
+  record_value("V4L2_%s_FMTS\n", aTypeStr);
+  for (fmt.index = 0;; fmt.index++) {
+    int result = ioctl(aFd, VIDIOC_ENUM_FMT, &fmt);
+    if (result < 0) {
+      break;
+    }
+    v4l2_pixfmt_to_str(fmt.pixelformat, pix_fmt_str);
+    record_value(" %s", pix_fmt_str);
+  }
+  record_value("\n");
+}
+
+// Probe a V4L2 device to work out what it supports
+static void v4l2_check_device(const char* aVideoDevice) {
+  int fd = -1;
+  int result = -1;
+
+  log("v4l2test probing device '%s'\n", aVideoDevice);
+
+  auto autoRelease = mozilla::MakeScopeExit([&] {
+    if (fd >= 0) {
+      close(fd);
+    }
+  });
+
+  fd = open(aVideoDevice, O_RDWR | O_NONBLOCK, 0);
+  if (fd < 0) {
+    record_value("ERROR\nV4L2 failed to open device %s: %s\n", aVideoDevice,
+                 strerror(errno));
+    return;
+  }
+
+  struct v4l2_capability cap {};
+  result = ioctl(fd, VIDIOC_QUERYCAP, &cap);
+  if (result < 0) {
+    record_value("ERROR\nV4L2 device %s failed to query capabilities\n",
+                 aVideoDevice);
+    return;
+  }
+  log("v4l2test driver %s card %s bus_info %s version %d\n", cap.driver,
+      cap.card, cap.bus_info, cap.version);
+
+  if (!(cap.capabilities & V4L2_CAP_DEVICE_CAPS)) {
+    record_value("ERROR\nV4L2 device %s does not support DEVICE_CAPS\n",
+                 aVideoDevice);
+    return;
+  }
+
+  if (!(cap.device_caps & V4L2_CAP_STREAMING)) {
+    record_value("ERROR\nV4L2 device %s does not support V4L2_CAP_STREAMING\n",
+                 aVideoDevice);
+    return;
+  }
+
+  // Work out whether the device supports planar or multiplaner bitbuffers and
+  // framebuffers
+  bool splane = cap.device_caps & V4L2_CAP_VIDEO_M2M;
+  bool mplane = cap.device_caps & V4L2_CAP_VIDEO_M2M_MPLANE;
+  if (!splane && !mplane) {
+    record_value("ERROR\nV4L2 device %s does not support M2M modes\n",
+                 aVideoDevice);
+    // (It's probably a webcam!)
+    return;
+  }
+  record_value("V4L2_SPLANE\n%s\n", splane ? "TRUE" : "FALSE");
+  record_value("V4L2_MPLANE\n%s\n", mplane ? "TRUE" : "FALSE");
+
+  // Now check the formats supported for CAPTURE and OUTPUT buffers.
+  // For a V4L2-M2M decoder, OUTPUT is actually the bitbuffers we put in and
+  // CAPTURE is the framebuffers we get out.
+  v4l2_enumfmt(
+      fd,
+      mplane ? V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE : V4L2_BUF_TYPE_VIDEO_CAPTURE,
+      "CAPTURE");
+  v4l2_enumfmt(
+      fd,
+      mplane ? V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE : V4L2_BUF_TYPE_VIDEO_OUTPUT,
+      "OUTPUT");
+
+  record_value("V4L2_SUPPORTED\nTRUE\n");
+}
+
+static void PrintUsage() {
+  printf(
+      "Firefox V4L2-M2M probe utility\n"
+      "\n"
+      "usage: v4l2test [options]\n"
+      "\n"
+      "Options:\n"
+      "\n"
+      "  -h --help                 show this message\n"
+      "  -d --device device        Probe a v4l2 device (e.g. /dev/video10)\n"
+      "\n");
+}
+
+int main(int argc, char** argv) {
+  struct option longOptions[] = {{"help", no_argument, nullptr, 'h'},
+                                 {"device", required_argument, nullptr, 'd'},
+                                 {nullptr, 0, nullptr, 0}};
+  const char* shortOptions = "hd:";
+  int c;
+  const char* device = nullptr;
+  while ((c = getopt_long(argc, argv, shortOptions, longOptions, nullptr)) !=
+         -1) {
+    switch (c) {
+      case 'd':
+        device = optarg;
+        break;
+      case 'h':
+      default:
+        break;
+    }
+  }
+
+  if (device) {
+#if defined(MOZ_ASAN) || defined(FUZZING)
+    // If handle_segv=1 (default), then glxtest crash will print a sanitizer
+    // report which can confuse the harness in fuzzing automation.
+    signal(SIGSEGV, SIG_DFL);
+#endif
+    const char* env = getenv("MOZ_GFX_DEBUG");
+    enable_logging = env && *env == '1';
+    output_pipe = OUTPUT_PIPE;
+    if (!enable_logging) {
+      close_logging();
+    }
+    v4l2_check_device(device);
+    record_flush();
+    return EXIT_SUCCESS;
+  }
+  PrintUsage();
+  return 0;
+}
diff --git a/widget/gtk/va_drmcommon.h b/widget/gtk/va_drmcommon.h
new file mode 100644
index 0000000000..e16f244a46
--- /dev/null
+++ b/widget/gtk/va_drmcommon.h
@@ -0,0 +1,156 @@
+/*
+ * va_drmcommon.h - Common utilities for DRM-based drivers
+ *
+ * Copyright (c) 2012 Intel Corporation. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL INTEL AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef VA_DRM_COMMON_H
+#define VA_DRM_COMMON_H
+
+#include <stdint.h>
+
+/** \brief DRM authentication type. */
+enum {
+  /** \brief Disconnected. */
+  VA_DRM_AUTH_NONE = 0,
+  /**
+   * \brief Connected. Authenticated with DRI1 protocol.
+   *
+   * @deprecated
+   * This is a deprecated authentication type. All DRI-based drivers have
+   * been migrated to use the DRI2 protocol. Newly written drivers shall
+   * use DRI2 protocol only, or a custom authentication means. e.g. opt
+   * for authenticating on the VA driver side, instead of libva side.
+   */
+  VA_DRM_AUTH_DRI1 = 1,
+  /**
+   * \brief Connected. Authenticated with DRI2 protocol.
+   *
+   * This is only useful to VA/X11 drivers. The libva-x11 library provides
+   * a helper function VA_DRI2Authenticate() for authenticating the
+   * connection. However, DRI2 conformant drivers don't need to call that
+   * function since authentication happens on the libva side, implicitly.
+   */
+  VA_DRM_AUTH_DRI2 = 2,
+  /**
+   * \brief Connected. Authenticated with some alternate raw protocol.
+   *
+   * This authentication mode is mainly used in non-VA/X11 drivers.
+   * Authentication happens through some alternative method, at the
+   * discretion of the VA driver implementation.
+   */
+  VA_DRM_AUTH_CUSTOM = 3
+};
+
+/** \brief Base DRM state. */
+struct drm_state {
+  /** \brief DRM connection descriptor. */
+  int fd;
+  /** \brief DRM authentication type. */
+  int auth_type;
+  /** \brief Reserved bytes for future use, must be zero */
+  int va_reserved[8];
+};
+
+/** \brief Kernel DRM buffer memory type.  */
+#define VA_SURFACE_ATTRIB_MEM_TYPE_KERNEL_DRM 0x10000000
+/** \brief DRM PRIME memory type (old version)
+ *
+ * This supports only single objects with restricted memory layout.
+ * Used with VASurfaceAttribExternalBuffers.
+ */
+#define VA_SURFACE_ATTRIB_MEM_TYPE_DRM_PRIME 0x20000000
+/** \brief DRM PRIME memory type
+ *
+ * Used with VADRMPRIMESurfaceDescriptor.
+ */
+#define VA_SURFACE_ATTRIB_MEM_TYPE_DRM_PRIME_2 0x40000000
+
+/**
+ * \brief External buffer descriptor for a DRM PRIME surface.
+ *
+ * For export, call vaExportSurfaceHandle() with mem_type set to
+ * VA_SURFACE_ATTRIB_MEM_TYPE_DRM_PRIME_2 and pass a pointer to an
+ * instance of this structure to fill.
+ * If VA_EXPORT_SURFACE_SEPARATE_LAYERS is specified on export, each
+ * layer will contain exactly one plane.  For example, an NV12
+ * surface will be exported as two layers, one of DRM_FORMAT_R8 and
+ * one of DRM_FORMAT_GR88.
+ * If VA_EXPORT_SURFACE_COMPOSED_LAYERS is specified on export,
+ * there will be exactly one layer.
+ *
+ * For import, call vaCreateSurfaces() with the MemoryType attribute
+ * set to VA_SURFACE_ATTRIB_MEM_TYPE_DRM_PRIME_2 and the
+ * ExternalBufferDescriptor attribute set to point to an array of
+ * num_surfaces instances of this structure.
+ * The number of planes which need to be provided for a given layer
+ * is dependent on both the format and the format modifier used for
+ * the objects containing it.  For example, the format DRM_FORMAT_RGBA
+ * normally requires one plane, but with the format modifier
+ * I915_FORMAT_MOD_Y_TILED_CCS it requires two planes - the first
+ * being the main data plane and the second containing the color
+ * control surface.
+ * Note that a given driver may only support a subset of possible
+ * representations of a particular format.  For example, it may only
+ * support NV12 surfaces when they are contained within a single DRM
+ * object, and therefore fail to create such surfaces if the two
+ * planes are in different DRM objects.
+ */
+typedef struct _VADRMPRIMESurfaceDescriptor {
+  /** Pixel format fourcc of the whole surface (VA_FOURCC_*). */
+  uint32_t fourcc;
+  /** Width of the surface in pixels. */
+  uint32_t width;
+  /** Height of the surface in pixels. */
+  uint32_t height;
+  /** Number of distinct DRM objects making up the surface. */
+  uint32_t num_objects;
+  /** Description of each object. */
+  struct {
+    /** DRM PRIME file descriptor for this object. */
+    int fd;
+    /** Total size of this object (may include regions which are
+     *  not part of the surface). */
+    uint32_t size;
+    /** Format modifier applied to this object. */
+    uint64_t drm_format_modifier;
+  } objects[4];
+  /** Number of layers making up the surface. */
+  uint32_t num_layers;
+  /** Description of each layer in the surface. */
+  struct {
+    /** DRM format fourcc of this layer (DRM_FOURCC_*). */
+    uint32_t drm_format;
+    /** Number of planes in this layer. */
+    uint32_t num_planes;
+    /** Index in the objects array of the object containing each
+     *  plane. */
+    uint32_t object_index[4];
+    /** Offset within the object of each plane. */
+    uint32_t offset[4];
+    /** Pitch of each plane. */
+    uint32_t pitch[4];
+  } layers[4];
+} VADRMPRIMESurfaceDescriptor;
+
+#endif /* VA_DRM_COMMON_H */
diff --git a/widget/gtk/vaapitest/moz.build b/widget/gtk/vaapitest/moz.build
new file mode 100644
index 0000000000..d9ea481ff1
--- /dev/null
+++ b/widget/gtk/vaapitest/moz.build
@@ -0,0 +1,20 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Toolkit", "Startup and Profile System")
+
+Program("vaapitest")
+SOURCES += [
+    "vaapitest.cpp",
+]
+CXXFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
+CXXFLAGS += CONFIG["MOZ_PANGO_CFLAGS"]
+OS_LIBS += CONFIG["MOZ_X11_LIBS"]
+OS_LIBS += CONFIG["MOZ_GTK3_LIBS"]
+
+USE_LIBS += ["mozva"]
+LOCAL_INCLUDES += ["/media/mozva"]
diff --git a/widget/gtk/vaapitest/vaapitest.cpp b/widget/gtk/vaapitest/vaapitest.cpp
new file mode 100644
index 0000000000..e2c0e0a742
--- /dev/null
+++ b/widget/gtk/vaapitest/vaapitest.cpp
@@ -0,0 +1,255 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <cstdio>
+#include <cstdlib>
+#include <dlfcn.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <stdint.h>
+#include <stdarg.h>
+
+#if defined(MOZ_ASAN) || defined(FUZZING)
+#  include <signal.h>
+#endif
+
+#include "mozilla/ScopeExit.h"
+
+#ifdef __SUNPRO_CC
+#  include <stdio.h>
+#endif
+
+#include "prlink.h"
+#include "va/va.h"
+
+#include "mozilla/GfxInfoUtils.h"
+
+// Print VA-API test results to stdout and logging to stderr
+#define OUTPUT_PIPE 1
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+// bits to use decoding vaapitest() return values.
+constexpr int CODEC_HW_H264 = 1 << 4;
+constexpr int CODEC_HW_VP8 = 1 << 5;
+constexpr int CODEC_HW_VP9 = 1 << 6;
+constexpr int CODEC_HW_AV1 = 1 << 7;
+
+// childgltest is declared inside extern "C" so that the name is not mangled.
+// The name is used in build/valgrind/x86_64-pc-linux-gnu.sup to suppress
+// memory leak errors because we run it inside a short lived fork and we don't
+// care about leaking memory
+extern "C" {
+
+static constexpr struct {
+  VAProfile mVAProfile;
+  const char* mName;
+} kVAAPiProfileName[] = {
+#define MAP(v) \
+  { VAProfile##v, #v }
+    MAP(H264ConstrainedBaseline),
+    MAP(H264Main),
+    MAP(H264High),
+    MAP(VP8Version0_3),
+    MAP(VP9Profile0),
+    MAP(VP9Profile2),
+    MAP(AV1Profile0),
+    MAP(AV1Profile1),
+#undef MAP
+};
+
+static const char* VAProfileName(VAProfile aVAProfile) {
+  for (const auto& profile : kVAAPiProfileName) {
+    if (profile.mVAProfile == aVAProfile) {
+      return profile.mName;
+    }
+  }
+  return nullptr;
+}
+
+static void vaapitest(const char* aRenderDevicePath) {
+  int renderDeviceFD = -1;
+  VAProfile* profiles = nullptr;
+  VAEntrypoint* entryPoints = nullptr;
+  VADisplay display = nullptr;
+  void* libDrm = nullptr;
+
+  log("vaapitest start, device %s\n", aRenderDevicePath);
+
+  auto autoRelease = mozilla::MakeScopeExit([&] {
+    free(profiles);
+    free(entryPoints);
+    if (display) {
+      vaTerminate(display);
+    }
+    if (libDrm) {
+      dlclose(libDrm);
+    }
+    if (renderDeviceFD > -1) {
+      close(renderDeviceFD);
+    }
+  });
+
+  renderDeviceFD = open(aRenderDevicePath, O_RDWR);
+  if (renderDeviceFD == -1) {
+    record_error("VA-API test failed: failed to open renderDeviceFD.");
+    return;
+  }
+
+  libDrm = dlopen("libva-drm.so.2", RTLD_LAZY);
+  if (!libDrm) {
+    log("vaapitest failed: libva-drm.so.2 is missing\n");
+    return;
+  }
+
+  static auto sVaGetDisplayDRM =
+      (void* (*)(int fd))dlsym(libDrm, "vaGetDisplayDRM");
+  if (!sVaGetDisplayDRM) {
+    record_error("VA-API test failed: sVaGetDisplayDRM is missing.");
+    return;
+  }
+
+  display = sVaGetDisplayDRM(renderDeviceFD);
+  if (!display) {
+    record_error("VA-API test failed: vaGetDisplayDRM failed.");
+    return;
+  }
+
+  int major, minor;
+  VAStatus status = vaInitialize(display, &major, &minor);
+  if (status != VA_STATUS_SUCCESS) {
+    log("vaInitialize failed %d\n", status);
+    return;
+  } else {
+    log("vaInitialize finished\n");
+  }
+
+  int maxProfiles = vaMaxNumProfiles(display);
+  int maxEntryPoints = vaMaxNumEntrypoints(display);
+  if (maxProfiles <= 0 || maxEntryPoints <= 0) {
+    record_error("VA-API test failed: wrong VAAPI profiles/entry point nums.");
+    return;
+  }
+
+  profiles = (VAProfile*)malloc(sizeof(VAProfile) * maxProfiles);
+  int numProfiles = 0;
+  status = vaQueryConfigProfiles(display, profiles, &numProfiles);
+  if (status != VA_STATUS_SUCCESS) {
+    record_error("VA-API test failed: vaQueryConfigProfiles() failed.");
+    return;
+  }
+  numProfiles = MIN(numProfiles, maxProfiles);
+
+  entryPoints = (VAEntrypoint*)malloc(sizeof(VAEntrypoint) * maxEntryPoints);
+  int codecs = 0;
+  bool foundProfile = false;
+  for (int p = 0; p < numProfiles; p++) {
+    VAProfile profile = profiles[p];
+
+    // Check only supported profiles
+    if (!VAProfileName(profile)) {
+      continue;
+    }
+
+    int numEntryPoints = 0;
+    status = vaQueryConfigEntrypoints(display, profile, entryPoints,
+                                      &numEntryPoints);
+    if (status != VA_STATUS_SUCCESS) {
+      continue;
+    }
+    numEntryPoints = MIN(numEntryPoints, maxEntryPoints);
+    for (int entry = 0; entry < numEntryPoints; entry++) {
+      if (entryPoints[entry] != VAEntrypointVLD) {
+        continue;
+      }
+      VAConfigID config = VA_INVALID_ID;
+      status = vaCreateConfig(display, profile, entryPoints[entry], nullptr, 0,
+                              &config);
+      if (status == VA_STATUS_SUCCESS) {
+        const char* profstr = VAProfileName(profile);
+        log("Profile: %s\n", profstr);
+        // VAProfileName returns null on failure, making the below calls safe
+        if (!strncmp(profstr, "H264", 4)) {
+          codecs |= CODEC_HW_H264;
+        } else if (!strncmp(profstr, "VP8", 3)) {
+          codecs |= CODEC_HW_VP8;
+        } else if (!strncmp(profstr, "VP9", 3)) {
+          codecs |= CODEC_HW_VP9;
+        } else if (!strncmp(profstr, "AV1", 3)) {
+          codecs |= CODEC_HW_AV1;
+        } else {
+          record_warning("VA-API test unknown profile.");
+        }
+        vaDestroyConfig(display, config);
+        foundProfile = true;
+      }
+    }
+  }
+  if (foundProfile) {
+    record_value("VAAPI_SUPPORTED\nTRUE\n");
+    record_value("VAAPI_HWCODECS\n%d\n", codecs);
+  } else {
+    record_value("VAAPI_SUPPORTED\nFALSE\n");
+  }
+  log("vaapitest finished\n");
+}
+
+}  // extern "C"
+
+static void PrintUsage() {
+  printf(
+      "Firefox VA-API probe utility\n"
+      "\n"
+      "usage: vaapitest [options]\n"
+      "\n"
+      "Options:\n"
+      "\n"
+      "  -h --help                 show this message\n"
+      "  -d --drm drm_device       probe VA-API on drm_device (may be "
+      "/dev/dri/renderD128)\n"
+      "\n");
+}
+
+int main(int argc, char** argv) {
+  struct option longOptions[] = {{"help", no_argument, NULL, 'h'},
+                                 {"drm", required_argument, NULL, 'd'},
+                                 {NULL, 0, NULL, 0}};
+  const char* shortOptions = "hd:";
+  int c;
+  const char* drmDevice = nullptr;
+  while ((c = getopt_long(argc, argv, shortOptions, longOptions, NULL)) != -1) {
+    switch (c) {
+      case 'd':
+        drmDevice = optarg;
+        break;
+      case 'h':
+      default:
+        break;
+    }
+  }
+  if (drmDevice) {
+#if defined(MOZ_ASAN) || defined(FUZZING)
+    // If handle_segv=1 (default), then glxtest crash will print a sanitizer
+    // report which can confuse the harness in fuzzing automation.
+    signal(SIGSEGV, SIG_DFL);
+#endif
+    const char* env = getenv("MOZ_GFX_DEBUG");
+    enable_logging = env && *env == '1';
+    output_pipe = OUTPUT_PIPE;
+    if (!enable_logging) {
+      close_logging();
+    }
+    vaapitest(drmDevice);
+    record_flush();
+    return EXIT_SUCCESS;
+  }
+  PrintUsage();
+  return 0;
+}
diff --git a/widget/gtk/wayland/fractional-scale-v1-client-protocol.h b/widget/gtk/wayland/fractional-scale-v1-client-protocol.h
new file mode 100644
index 0000000000..3db2eaad6b
--- /dev/null
+++ b/widget/gtk/wayland/fractional-scale-v1-client-protocol.h
@@ -0,0 +1,268 @@
+/* Generated by wayland-scanner 1.19.0 */
+
+#ifndef FRACTIONAL_SCALE_V1_CLIENT_PROTOCOL_H
+#define FRACTIONAL_SCALE_V1_CLIENT_PROTOCOL_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include "wayland-client.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @page page_fractional_scale_v1 The fractional_scale_v1 protocol
+ * Protocol for requesting fractional surface scales
+ *
+ * @section page_desc_fractional_scale_v1 Description
+ *
+ * This protocol allows a compositor to suggest for surfaces to render at
+ * fractional scales.
+ *
+ * A client can submit scaled content by utilizing wp_viewport. This is done by
+ * creating a wp_viewport object for the surface and setting the destination
+ * rectangle to the surface size before the scale factor is applied.
+ *
+ * The buffer size is calculated by multiplying the surface size by the
+ * intended scale.
+ *
+ * The wl_surface buffer scale should remain set to 1.
+ *
+ * If a surface has a surface-local size of 100 px by 50 px and wishes to
+ * submit buffers with a scale of 1.5, then a buffer of 150px by 75 px should
+ * be used and the wp_viewport destination rectangle should be 100 px by 50 px.
+ *
+ * For toplevel surfaces, the size is rounded halfway away from zero. The
+ * rounding algorithm for subsurface position and size is not defined.
+ *
+ * @section page_ifaces_fractional_scale_v1 Interfaces
+ * - @subpage page_iface_wp_fractional_scale_manager_v1 - fractional surface
+ * scale information
+ * - @subpage page_iface_wp_fractional_scale_v1 - fractional scale interface to
+ * a wl_surface
+ * @section page_copyright_fractional_scale_v1 Copyright
+ * <pre>
+ *
+ * Copyright © 2022 Kenny Levinsen
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ * </pre>
+ */
+struct wl_surface;
+struct wp_fractional_scale_manager_v1;
+struct wp_fractional_scale_v1;
+
+#ifndef WP_FRACTIONAL_SCALE_MANAGER_V1_INTERFACE
+#  define WP_FRACTIONAL_SCALE_MANAGER_V1_INTERFACE
+/**
+ * @page page_iface_wp_fractional_scale_manager_v1
+ * wp_fractional_scale_manager_v1
+ * @section page_iface_wp_fractional_scale_manager_v1_desc Description
+ *
+ * A global interface for requesting surfaces to use fractional scales.
+ * @section page_iface_wp_fractional_scale_manager_v1_api API
+ * See @ref iface_wp_fractional_scale_manager_v1.
+ */
+/**
+ * @defgroup iface_wp_fractional_scale_manager_v1 The
+ * wp_fractional_scale_manager_v1 interface
+ *
+ * A global interface for requesting surfaces to use fractional scales.
+ */
+extern const struct wl_interface wp_fractional_scale_manager_v1_interface;
+#endif
+#ifndef WP_FRACTIONAL_SCALE_V1_INTERFACE
+#  define WP_FRACTIONAL_SCALE_V1_INTERFACE
+/**
+ * @page page_iface_wp_fractional_scale_v1 wp_fractional_scale_v1
+ * @section page_iface_wp_fractional_scale_v1_desc Description
+ *
+ * An additional interface to a wl_surface object which allows the compositor
+ * to inform the client of the preferred scale.
+ * @section page_iface_wp_fractional_scale_v1_api API
+ * See @ref iface_wp_fractional_scale_v1.
+ */
+/**
+ * @defgroup iface_wp_fractional_scale_v1 The wp_fractional_scale_v1 interface
+ *
+ * An additional interface to a wl_surface object which allows the compositor
+ * to inform the client of the preferred scale.
+ */
+extern const struct wl_interface wp_fractional_scale_v1_interface;
+#endif
+
+#ifndef WP_FRACTIONAL_SCALE_MANAGER_V1_ERROR_ENUM
+#  define WP_FRACTIONAL_SCALE_MANAGER_V1_ERROR_ENUM
+enum wp_fractional_scale_manager_v1_error {
+  /**
+   * the surface already has a fractional_scale object associated
+   */
+  WP_FRACTIONAL_SCALE_MANAGER_V1_ERROR_FRACTIONAL_SCALE_EXISTS = 0,
+};
+#endif /* WP_FRACTIONAL_SCALE_MANAGER_V1_ERROR_ENUM */
+
+#define WP_FRACTIONAL_SCALE_MANAGER_V1_DESTROY 0
+#define WP_FRACTIONAL_SCALE_MANAGER_V1_GET_FRACTIONAL_SCALE 1
+
+/**
+ * @ingroup iface_wp_fractional_scale_manager_v1
+ */
+#define WP_FRACTIONAL_SCALE_MANAGER_V1_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_wp_fractional_scale_manager_v1
+ */
+#define WP_FRACTIONAL_SCALE_MANAGER_V1_GET_FRACTIONAL_SCALE_SINCE_VERSION 1
+
+/** @ingroup iface_wp_fractional_scale_manager_v1 */
+static inline void wp_fractional_scale_manager_v1_set_user_data(
+    struct wp_fractional_scale_manager_v1* wp_fractional_scale_manager_v1,
+    void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)wp_fractional_scale_manager_v1,
+                         user_data);
+}
+
+/** @ingroup iface_wp_fractional_scale_manager_v1 */
+static inline void* wp_fractional_scale_manager_v1_get_user_data(
+    struct wp_fractional_scale_manager_v1* wp_fractional_scale_manager_v1) {
+  return wl_proxy_get_user_data(
+      (struct wl_proxy*)wp_fractional_scale_manager_v1);
+}
+
+static inline uint32_t wp_fractional_scale_manager_v1_get_version(
+    struct wp_fractional_scale_manager_v1* wp_fractional_scale_manager_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)wp_fractional_scale_manager_v1);
+}
+
+/**
+ * @ingroup iface_wp_fractional_scale_manager_v1
+ *
+ * Informs the server that the client will not be using this protocol
+ * object anymore. This does not affect any other objects,
+ * wp_fractional_scale_v1 objects included.
+ */
+static inline void wp_fractional_scale_manager_v1_destroy(
+    struct wp_fractional_scale_manager_v1* wp_fractional_scale_manager_v1) {
+  wl_proxy_marshal((struct wl_proxy*)wp_fractional_scale_manager_v1,
+                   WP_FRACTIONAL_SCALE_MANAGER_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)wp_fractional_scale_manager_v1);
+}
+
+/**
+ * @ingroup iface_wp_fractional_scale_manager_v1
+ *
+ * Create an add-on object for the the wl_surface to let the compositor
+ * request fractional scales. If the given wl_surface already has a
+ * wp_fractional_scale_v1 object associated, the fractional_scale_exists
+ * protocol error is raised.
+ */
+static inline struct wp_fractional_scale_v1*
+wp_fractional_scale_manager_v1_get_fractional_scale(
+    struct wp_fractional_scale_manager_v1* wp_fractional_scale_manager_v1,
+    struct wl_surface* surface) {
+  struct wl_proxy* id;
+
+  id = wl_proxy_marshal_constructor(
+      (struct wl_proxy*)wp_fractional_scale_manager_v1,
+      WP_FRACTIONAL_SCALE_MANAGER_V1_GET_FRACTIONAL_SCALE,
+      &wp_fractional_scale_v1_interface, NULL, surface);
+
+  return (struct wp_fractional_scale_v1*)id;
+}
+
+/**
+ * @ingroup iface_wp_fractional_scale_v1
+ * @struct wp_fractional_scale_v1_listener
+ */
+struct wp_fractional_scale_v1_listener {
+  /**
+   * notify of new preferred scale
+   *
+   * Notification of a new preferred scale for this surface that
+   * the compositor suggests that the client should use.
+   *
+   * The sent scale is the numerator of a fraction with a denominator
+   * of 120.
+   * @param scale the new preferred scale
+   */
+  void (*preferred_scale)(void* data,
+                          struct wp_fractional_scale_v1* wp_fractional_scale_v1,
+                          uint32_t scale);
+};
+
+/**
+ * @ingroup iface_wp_fractional_scale_v1
+ */
+static inline int wp_fractional_scale_v1_add_listener(
+    struct wp_fractional_scale_v1* wp_fractional_scale_v1,
+    const struct wp_fractional_scale_v1_listener* listener, void* data) {
+  return wl_proxy_add_listener((struct wl_proxy*)wp_fractional_scale_v1,
+                               (void (**)(void))listener, data);
+}
+
+#define WP_FRACTIONAL_SCALE_V1_DESTROY 0
+
+/**
+ * @ingroup iface_wp_fractional_scale_v1
+ */
+#define WP_FRACTIONAL_SCALE_V1_PREFERRED_SCALE_SINCE_VERSION 1
+
+/**
+ * @ingroup iface_wp_fractional_scale_v1
+ */
+#define WP_FRACTIONAL_SCALE_V1_DESTROY_SINCE_VERSION 1
+
+/** @ingroup iface_wp_fractional_scale_v1 */
+static inline void wp_fractional_scale_v1_set_user_data(
+    struct wp_fractional_scale_v1* wp_fractional_scale_v1, void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)wp_fractional_scale_v1, user_data);
+}
+
+/** @ingroup iface_wp_fractional_scale_v1 */
+static inline void* wp_fractional_scale_v1_get_user_data(
+    struct wp_fractional_scale_v1* wp_fractional_scale_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)wp_fractional_scale_v1);
+}
+
+static inline uint32_t wp_fractional_scale_v1_get_version(
+    struct wp_fractional_scale_v1* wp_fractional_scale_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)wp_fractional_scale_v1);
+}
+
+/**
+ * @ingroup iface_wp_fractional_scale_v1
+ *
+ * Destroy the fractional scale object. When this object is destroyed,
+ * preferred_scale events will no longer be sent.
+ */
+static inline void wp_fractional_scale_v1_destroy(
+    struct wp_fractional_scale_v1* wp_fractional_scale_v1) {
+  wl_proxy_marshal((struct wl_proxy*)wp_fractional_scale_v1,
+                   WP_FRACTIONAL_SCALE_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)wp_fractional_scale_v1);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/widget/gtk/wayland/fractional-scale-v1-protocol.c b/widget/gtk/wayland/fractional-scale-v1-protocol.c
new file mode 100644
index 0000000000..4841533289
--- /dev/null
+++ b/widget/gtk/wayland/fractional-scale-v1-protocol.c
@@ -0,0 +1,73 @@
+/* Generated by wayland-scanner 1.19.0 */
+
+/*
+ * Copyright © 2022 Kenny Levinsen
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include "wayland-util.h"
+
+#ifndef __has_attribute
+#  define __has_attribute(x) 0 /* Compatibility with non-clang compilers. */
+#endif
+
+#if (__has_attribute(visibility) || defined(__GNUC__) && __GNUC__ >= 4)
+#  define WL_PRIVATE __attribute__((visibility("hidden")))
+#else
+#  define WL_PRIVATE
+#endif
+
+#pragma GCC visibility push(default)
+extern const struct wl_interface wl_surface_interface;
+#pragma GCC visibility pop
+extern const struct wl_interface wp_fractional_scale_v1_interface;
+
+static const struct wl_interface* fractional_scale_v1_types[] = {
+    NULL,
+    &wp_fractional_scale_v1_interface,
+    &wl_surface_interface,
+};
+
+static const struct wl_message wp_fractional_scale_manager_v1_requests[] = {
+    {"destroy", "", fractional_scale_v1_types + 0},
+    {"get_fractional_scale", "no", fractional_scale_v1_types + 1},
+};
+
+WL_PRIVATE const struct wl_interface wp_fractional_scale_manager_v1_interface =
+    {
+        "wp_fractional_scale_manager_v1",        1, 2,
+        wp_fractional_scale_manager_v1_requests, 0, NULL,
+};
+
+static const struct wl_message wp_fractional_scale_v1_requests[] = {
+    {"destroy", "", fractional_scale_v1_types + 0},
+};
+
+static const struct wl_message wp_fractional_scale_v1_events[] = {
+    {"preferred_scale", "u", fractional_scale_v1_types + 0},
+};
+
+WL_PRIVATE const struct wl_interface wp_fractional_scale_v1_interface = {
+    "wp_fractional_scale_v1",        1, 1,
+    wp_fractional_scale_v1_requests, 1, wp_fractional_scale_v1_events,
+};
diff --git a/widget/gtk/wayland/idle-inhibit-unstable-v1-client-protocol.h b/widget/gtk/wayland/idle-inhibit-unstable-v1-client-protocol.h
new file mode 100644
index 0000000000..3ae2303b3c
--- /dev/null
+++ b/widget/gtk/wayland/idle-inhibit-unstable-v1-client-protocol.h
@@ -0,0 +1,228 @@
+/* Generated by wayland-scanner 1.16.0 */
+
+#ifndef IDLE_INHIBIT_UNSTABLE_V1_CLIENT_PROTOCOL_H
+#define IDLE_INHIBIT_UNSTABLE_V1_CLIENT_PROTOCOL_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include "wayland-client.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @page page_idle_inhibit_unstable_v1 The idle_inhibit_unstable_v1 protocol
+ * @section page_ifaces_idle_inhibit_unstable_v1 Interfaces
+ * - @subpage page_iface_zwp_idle_inhibit_manager_v1 - control behavior when
+ * display idles
+ * - @subpage page_iface_zwp_idle_inhibitor_v1 - context object for inhibiting
+ * idle behavior
+ * @section page_copyright_idle_inhibit_unstable_v1 Copyright
+ * <pre>
+ *
+ * Copyright © 2015 Samsung Electronics Co., Ltd
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ * </pre>
+ */
+struct wl_surface;
+struct zwp_idle_inhibit_manager_v1;
+struct zwp_idle_inhibitor_v1;
+
+/**
+ * @page page_iface_zwp_idle_inhibit_manager_v1 zwp_idle_inhibit_manager_v1
+ * @section page_iface_zwp_idle_inhibit_manager_v1_desc Description
+ *
+ * This interface permits inhibiting the idle behavior such as screen
+ * blanking, locking, and screensaving.  The client binds the idle manager
+ * globally, then creates idle-inhibitor objects for each surface.
+ *
+ * Warning! The protocol described in this file is experimental and
+ * backward incompatible changes may be made. Backward compatible changes
+ * may be added together with the corresponding interface version bump.
+ * Backward incompatible changes are done by bumping the version number in
+ * the protocol and interface names and resetting the interface version.
+ * Once the protocol is to be declared stable, the 'z' prefix and the
+ * version number in the protocol and interface names are removed and the
+ * interface version number is reset.
+ * @section page_iface_zwp_idle_inhibit_manager_v1_api API
+ * See @ref iface_zwp_idle_inhibit_manager_v1.
+ */
+/**
+ * @defgroup iface_zwp_idle_inhibit_manager_v1 The zwp_idle_inhibit_manager_v1
+ * interface
+ *
+ * This interface permits inhibiting the idle behavior such as screen
+ * blanking, locking, and screensaving.  The client binds the idle manager
+ * globally, then creates idle-inhibitor objects for each surface.
+ *
+ * Warning! The protocol described in this file is experimental and
+ * backward incompatible changes may be made. Backward compatible changes
+ * may be added together with the corresponding interface version bump.
+ * Backward incompatible changes are done by bumping the version number in
+ * the protocol and interface names and resetting the interface version.
+ * Once the protocol is to be declared stable, the 'z' prefix and the
+ * version number in the protocol and interface names are removed and the
+ * interface version number is reset.
+ */
+extern const struct wl_interface zwp_idle_inhibit_manager_v1_interface;
+/**
+ * @page page_iface_zwp_idle_inhibitor_v1 zwp_idle_inhibitor_v1
+ * @section page_iface_zwp_idle_inhibitor_v1_desc Description
+ *
+ * An idle inhibitor prevents the output that the associated surface is
+ * visible on from being set to a state where it is not visually usable due
+ * to lack of user interaction (e.g. blanked, dimmed, locked, set to power
+ * save, etc.)  Any screensaver processes are also blocked from displaying.
+ *
+ * If the surface is destroyed, unmapped, becomes occluded, loses
+ * visibility, or otherwise becomes not visually relevant for the user, the
+ * idle inhibitor will not be honored by the compositor; if the surface
+ * subsequently regains visibility the inhibitor takes effect once again.
+ * Likewise, the inhibitor isn't honored if the system was already idled at
+ * the time the inhibitor was established, although if the system later
+ * de-idles and re-idles the inhibitor will take effect.
+ * @section page_iface_zwp_idle_inhibitor_v1_api API
+ * See @ref iface_zwp_idle_inhibitor_v1.
+ */
+/**
+ * @defgroup iface_zwp_idle_inhibitor_v1 The zwp_idle_inhibitor_v1 interface
+ *
+ * An idle inhibitor prevents the output that the associated surface is
+ * visible on from being set to a state where it is not visually usable due
+ * to lack of user interaction (e.g. blanked, dimmed, locked, set to power
+ * save, etc.)  Any screensaver processes are also blocked from displaying.
+ *
+ * If the surface is destroyed, unmapped, becomes occluded, loses
+ * visibility, or otherwise becomes not visually relevant for the user, the
+ * idle inhibitor will not be honored by the compositor; if the surface
+ * subsequently regains visibility the inhibitor takes effect once again.
+ * Likewise, the inhibitor isn't honored if the system was already idled at
+ * the time the inhibitor was established, although if the system later
+ * de-idles and re-idles the inhibitor will take effect.
+ */
+extern const struct wl_interface zwp_idle_inhibitor_v1_interface;
+
+#define ZWP_IDLE_INHIBIT_MANAGER_V1_DESTROY 0
+#define ZWP_IDLE_INHIBIT_MANAGER_V1_CREATE_INHIBITOR 1
+
+/**
+ * @ingroup iface_zwp_idle_inhibit_manager_v1
+ */
+#define ZWP_IDLE_INHIBIT_MANAGER_V1_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_idle_inhibit_manager_v1
+ */
+#define ZWP_IDLE_INHIBIT_MANAGER_V1_CREATE_INHIBITOR_SINCE_VERSION 1
+
+/** @ingroup iface_zwp_idle_inhibit_manager_v1 */
+static inline void zwp_idle_inhibit_manager_v1_set_user_data(
+    struct zwp_idle_inhibit_manager_v1* zwp_idle_inhibit_manager_v1,
+    void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)zwp_idle_inhibit_manager_v1,
+                         user_data);
+}
+
+/** @ingroup iface_zwp_idle_inhibit_manager_v1 */
+static inline void* zwp_idle_inhibit_manager_v1_get_user_data(
+    struct zwp_idle_inhibit_manager_v1* zwp_idle_inhibit_manager_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)zwp_idle_inhibit_manager_v1);
+}
+
+static inline uint32_t zwp_idle_inhibit_manager_v1_get_version(
+    struct zwp_idle_inhibit_manager_v1* zwp_idle_inhibit_manager_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)zwp_idle_inhibit_manager_v1);
+}
+
+/**
+ * @ingroup iface_zwp_idle_inhibit_manager_v1
+ *
+ * Destroy the inhibit manager.
+ */
+static inline void zwp_idle_inhibit_manager_v1_destroy(
+    struct zwp_idle_inhibit_manager_v1* zwp_idle_inhibit_manager_v1) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_idle_inhibit_manager_v1,
+                   ZWP_IDLE_INHIBIT_MANAGER_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)zwp_idle_inhibit_manager_v1);
+}
+
+/**
+ * @ingroup iface_zwp_idle_inhibit_manager_v1
+ *
+ * Create a new inhibitor object associated with the given surface.
+ */
+static inline struct zwp_idle_inhibitor_v1*
+zwp_idle_inhibit_manager_v1_create_inhibitor(
+    struct zwp_idle_inhibit_manager_v1* zwp_idle_inhibit_manager_v1,
+    struct wl_surface* surface) {
+  struct wl_proxy* id;
+
+  id = wl_proxy_marshal_constructor(
+      (struct wl_proxy*)zwp_idle_inhibit_manager_v1,
+      ZWP_IDLE_INHIBIT_MANAGER_V1_CREATE_INHIBITOR,
+      &zwp_idle_inhibitor_v1_interface, NULL, surface);
+
+  return (struct zwp_idle_inhibitor_v1*)id;
+}
+
+#define ZWP_IDLE_INHIBITOR_V1_DESTROY 0
+
+/**
+ * @ingroup iface_zwp_idle_inhibitor_v1
+ */
+#define ZWP_IDLE_INHIBITOR_V1_DESTROY_SINCE_VERSION 1
+
+/** @ingroup iface_zwp_idle_inhibitor_v1 */
+static inline void zwp_idle_inhibitor_v1_set_user_data(
+    struct zwp_idle_inhibitor_v1* zwp_idle_inhibitor_v1, void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)zwp_idle_inhibitor_v1, user_data);
+}
+
+/** @ingroup iface_zwp_idle_inhibitor_v1 */
+static inline void* zwp_idle_inhibitor_v1_get_user_data(
+    struct zwp_idle_inhibitor_v1* zwp_idle_inhibitor_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)zwp_idle_inhibitor_v1);
+}
+
+static inline uint32_t zwp_idle_inhibitor_v1_get_version(
+    struct zwp_idle_inhibitor_v1* zwp_idle_inhibitor_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)zwp_idle_inhibitor_v1);
+}
+
+/**
+ * @ingroup iface_zwp_idle_inhibitor_v1
+ *
+ * Remove the inhibitor effect from the associated wl_surface.
+ */
+static inline void zwp_idle_inhibitor_v1_destroy(
+    struct zwp_idle_inhibitor_v1* zwp_idle_inhibitor_v1) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_idle_inhibitor_v1,
+                   ZWP_IDLE_INHIBITOR_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)zwp_idle_inhibitor_v1);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/widget/gtk/wayland/idle-inhibit-unstable-v1-protocol.c b/widget/gtk/wayland/idle-inhibit-unstable-v1-protocol.c
new file mode 100644
index 0000000000..579095e003
--- /dev/null
+++ b/widget/gtk/wayland/idle-inhibit-unstable-v1-protocol.c
@@ -0,0 +1,60 @@
+/* Generated by wayland-scanner 1.16.0 */
+
+/*
+ * Copyright © 2015 Samsung Electronics Co., Ltd
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include "wayland-util.h"
+
+#ifndef __has_attribute
+#  define __has_attribute(x) 0 /* Compatibility with non-clang compilers. */
+#endif
+
+#pragma GCC visibility push(default)
+extern const struct wl_interface wl_surface_interface;
+extern const struct wl_interface zwp_idle_inhibitor_v1_interface;
+#pragma GCC visibility pop
+
+static const struct wl_interface* types[] = {
+    &zwp_idle_inhibitor_v1_interface,
+    &wl_surface_interface,
+};
+
+static const struct wl_message zwp_idle_inhibit_manager_v1_requests[] = {
+    {"destroy", "", types + 0},
+    {"create_inhibitor", "no", types + 0},
+};
+
+const struct wl_interface zwp_idle_inhibit_manager_v1_interface = {
+    "zwp_idle_inhibit_manager_v1",        1, 2,
+    zwp_idle_inhibit_manager_v1_requests, 0, NULL,
+};
+
+static const struct wl_message zwp_idle_inhibitor_v1_requests[] = {
+    {"destroy", "", types + 0},
+};
+
+const struct wl_interface zwp_idle_inhibitor_v1_interface = {
+    "zwp_idle_inhibitor_v1", 1, 1, zwp_idle_inhibitor_v1_requests, 0, NULL,
+};
diff --git a/widget/gtk/wayland/linux-dmabuf-unstable-v1-client-protocol.h b/widget/gtk/wayland/linux-dmabuf-unstable-v1-client-protocol.h
new file mode 100644
index 0000000000..cff0426a9c
--- /dev/null
+++ b/widget/gtk/wayland/linux-dmabuf-unstable-v1-client-protocol.h
@@ -0,0 +1,650 @@
+/* Generated by wayland-scanner 1.17.0 */
+
+#ifndef LINUX_DMABUF_UNSTABLE_V1_CLIENT_PROTOCOL_H
+#define LINUX_DMABUF_UNSTABLE_V1_CLIENT_PROTOCOL_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include "wayland-client.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @page page_linux_dmabuf_unstable_v1 The linux_dmabuf_unstable_v1 protocol
+ * @section page_ifaces_linux_dmabuf_unstable_v1 Interfaces
+ * - @subpage page_iface_zwp_linux_dmabuf_v1 - factory for creating dmabuf-based
+ * wl_buffers
+ * - @subpage page_iface_zwp_linux_buffer_params_v1 - parameters for creating a
+ * dmabuf-based wl_buffer
+ * @section page_copyright_linux_dmabuf_unstable_v1 Copyright
+ * <pre>
+ *
+ * Copyright © 2014, 2015 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ * </pre>
+ */
+struct wl_buffer;
+struct zwp_linux_buffer_params_v1;
+struct zwp_linux_dmabuf_v1;
+
+/**
+ * @page page_iface_zwp_linux_dmabuf_v1 zwp_linux_dmabuf_v1
+ * @section page_iface_zwp_linux_dmabuf_v1_desc Description
+ *
+ * Following the interfaces from:
+ * https://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_import.txt
+ * and the Linux DRM sub-system's AddFb2 ioctl.
+ *
+ * This interface offers ways to create generic dmabuf-based
+ * wl_buffers. Immediately after a client binds to this interface,
+ * the set of supported formats and format modifiers is sent with
+ * 'format' and 'modifier' events.
+ *
+ * The following are required from clients:
+ *
+ * - Clients must ensure that either all data in the dma-buf is
+ * coherent for all subsequent read access or that coherency is
+ * correctly handled by the underlying kernel-side dma-buf
+ * implementation.
+ *
+ * - Don't make any more attachments after sending the buffer to the
+ * compositor. Making more attachments later increases the risk of
+ * the compositor not being able to use (re-import) an existing
+ * dmabuf-based wl_buffer.
+ *
+ * The underlying graphics stack must ensure the following:
+ *
+ * - The dmabuf file descriptors relayed to the server will stay valid
+ * for the whole lifetime of the wl_buffer. This means the server may
+ * at any time use those fds to import the dmabuf into any kernel
+ * sub-system that might accept it.
+ *
+ * To create a wl_buffer from one or more dmabufs, a client creates a
+ * zwp_linux_dmabuf_params_v1 object with a zwp_linux_dmabuf_v1.create_params
+ * request. All planes required by the intended format are added with
+ * the 'add' request. Finally, a 'create' or 'create_immed' request is
+ * issued, which has the following outcome depending on the import success.
+ *
+ * The 'create' request,
+ * - on success, triggers a 'created' event which provides the final
+ * wl_buffer to the client.
+ * - on failure, triggers a 'failed' event to convey that the server
+ * cannot use the dmabufs received from the client.
+ *
+ * For the 'create_immed' request,
+ * - on success, the server immediately imports the added dmabufs to
+ * create a wl_buffer. No event is sent from the server in this case.
+ * - on failure, the server can choose to either:
+ * - terminate the client by raising a fatal error.
+ * - mark the wl_buffer as failed, and send a 'failed' event to the
+ * client. If the client uses a failed wl_buffer as an argument to any
+ * request, the behaviour is compositor implementation-defined.
+ *
+ * Warning! The protocol described in this file is experimental and
+ * backward incompatible changes may be made. Backward compatible changes
+ * may be added together with the corresponding interface version bump.
+ * Backward incompatible changes are done by bumping the version number in
+ * the protocol and interface names and resetting the interface version.
+ * Once the protocol is to be declared stable, the 'z' prefix and the
+ * version number in the protocol and interface names are removed and the
+ * interface version number is reset.
+ * @section page_iface_zwp_linux_dmabuf_v1_api API
+ * See @ref iface_zwp_linux_dmabuf_v1.
+ */
+/**
+ * @defgroup iface_zwp_linux_dmabuf_v1 The zwp_linux_dmabuf_v1 interface
+ *
+ * Following the interfaces from:
+ * https://www.khronos.org/registry/egl/extensions/EXT/EGL_EXT_image_dma_buf_import.txt
+ * and the Linux DRM sub-system's AddFb2 ioctl.
+ *
+ * This interface offers ways to create generic dmabuf-based
+ * wl_buffers. Immediately after a client binds to this interface,
+ * the set of supported formats and format modifiers is sent with
+ * 'format' and 'modifier' events.
+ *
+ * The following are required from clients:
+ *
+ * - Clients must ensure that either all data in the dma-buf is
+ * coherent for all subsequent read access or that coherency is
+ * correctly handled by the underlying kernel-side dma-buf
+ * implementation.
+ *
+ * - Don't make any more attachments after sending the buffer to the
+ * compositor. Making more attachments later increases the risk of
+ * the compositor not being able to use (re-import) an existing
+ * dmabuf-based wl_buffer.
+ *
+ * The underlying graphics stack must ensure the following:
+ *
+ * - The dmabuf file descriptors relayed to the server will stay valid
+ * for the whole lifetime of the wl_buffer. This means the server may
+ * at any time use those fds to import the dmabuf into any kernel
+ * sub-system that might accept it.
+ *
+ * To create a wl_buffer from one or more dmabufs, a client creates a
+ * zwp_linux_dmabuf_params_v1 object with a zwp_linux_dmabuf_v1.create_params
+ * request. All planes required by the intended format are added with
+ * the 'add' request. Finally, a 'create' or 'create_immed' request is
+ * issued, which has the following outcome depending on the import success.
+ *
+ * The 'create' request,
+ * - on success, triggers a 'created' event which provides the final
+ * wl_buffer to the client.
+ * - on failure, triggers a 'failed' event to convey that the server
+ * cannot use the dmabufs received from the client.
+ *
+ * For the 'create_immed' request,
+ * - on success, the server immediately imports the added dmabufs to
+ * create a wl_buffer. No event is sent from the server in this case.
+ * - on failure, the server can choose to either:
+ * - terminate the client by raising a fatal error.
+ * - mark the wl_buffer as failed, and send a 'failed' event to the
+ * client. If the client uses a failed wl_buffer as an argument to any
+ * request, the behaviour is compositor implementation-defined.
+ *
+ * Warning! The protocol described in this file is experimental and
+ * backward incompatible changes may be made. Backward compatible changes
+ * may be added together with the corresponding interface version bump.
+ * Backward incompatible changes are done by bumping the version number in
+ * the protocol and interface names and resetting the interface version.
+ * Once the protocol is to be declared stable, the 'z' prefix and the
+ * version number in the protocol and interface names are removed and the
+ * interface version number is reset.
+ */
+extern const struct wl_interface zwp_linux_dmabuf_v1_interface;
+/**
+ * @page page_iface_zwp_linux_buffer_params_v1 zwp_linux_buffer_params_v1
+ * @section page_iface_zwp_linux_buffer_params_v1_desc Description
+ *
+ * This temporary object is a collection of dmabufs and other
+ * parameters that together form a single logical buffer. The temporary
+ * object may eventually create one wl_buffer unless cancelled by
+ * destroying it before requesting 'create'.
+ *
+ * Single-planar formats only require one dmabuf, however
+ * multi-planar formats may require more than one dmabuf. For all
+ * formats, an 'add' request must be called once per plane (even if the
+ * underlying dmabuf fd is identical).
+ *
+ * You must use consecutive plane indices ('plane_idx' argument for 'add')
+ * from zero to the number of planes used by the drm_fourcc format code.
+ * All planes required by the format must be given exactly once, but can
+ * be given in any order. Each plane index can be set only once.
+ * @section page_iface_zwp_linux_buffer_params_v1_api API
+ * See @ref iface_zwp_linux_buffer_params_v1.
+ */
+/**
+ * @defgroup iface_zwp_linux_buffer_params_v1 The zwp_linux_buffer_params_v1
+ * interface
+ *
+ * This temporary object is a collection of dmabufs and other
+ * parameters that together form a single logical buffer. The temporary
+ * object may eventually create one wl_buffer unless cancelled by
+ * destroying it before requesting 'create'.
+ *
+ * Single-planar formats only require one dmabuf, however
+ * multi-planar formats may require more than one dmabuf. For all
+ * formats, an 'add' request must be called once per plane (even if the
+ * underlying dmabuf fd is identical).
+ *
+ * You must use consecutive plane indices ('plane_idx' argument for 'add')
+ * from zero to the number of planes used by the drm_fourcc format code.
+ * All planes required by the format must be given exactly once, but can
+ * be given in any order. Each plane index can be set only once.
+ */
+extern const struct wl_interface zwp_linux_buffer_params_v1_interface;
+
+/**
+ * @ingroup iface_zwp_linux_dmabuf_v1
+ * @struct zwp_linux_dmabuf_v1_listener
+ */
+struct zwp_linux_dmabuf_v1_listener {
+  /**
+   * supported buffer format
+   *
+   * This event advertises one buffer format that the server
+   * supports. All the supported formats are advertised once when the
+   * client binds to this interface. A roundtrip after binding
+   * guarantees that the client has received all supported formats.
+   *
+   * For the definition of the format codes, see the
+   * zwp_linux_buffer_params_v1::create request.
+   *
+   * Warning: the 'format' event is likely to be deprecated and
+   * replaced with the 'modifier' event introduced in
+   * zwp_linux_dmabuf_v1 version 3, described below. Please refrain
+   * from using the information received from this event.
+   * @param format DRM_FORMAT code
+   */
+  void (*format)(void* data, struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf_v1,
+                 uint32_t format);
+  /**
+   * supported buffer format modifier
+   *
+   * This event advertises the formats that the server supports,
+   * along with the modifiers supported for each format. All the
+   * supported modifiers for all the supported formats are advertised
+   * once when the client binds to this interface. A roundtrip after
+   * binding guarantees that the client has received all supported
+   * format-modifier pairs.
+   *
+   * For the definition of the format and modifier codes, see the
+   * zwp_linux_buffer_params_v1::create request.
+   * @param format DRM_FORMAT code
+   * @param modifier_hi high 32 bits of layout modifier
+   * @param modifier_lo low 32 bits of layout modifier
+   * @since 3
+   */
+  void (*modifier)(void* data, struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf_v1,
+                   uint32_t format, uint32_t modifier_hi, uint32_t modifier_lo);
+};
+
+/**
+ * @ingroup iface_zwp_linux_dmabuf_v1
+ */
+static inline int zwp_linux_dmabuf_v1_add_listener(
+    struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf_v1,
+    const struct zwp_linux_dmabuf_v1_listener* listener, void* data) {
+  return wl_proxy_add_listener((struct wl_proxy*)zwp_linux_dmabuf_v1,
+                               (void (**)(void))listener, data);
+}
+
+#define ZWP_LINUX_DMABUF_V1_DESTROY 0
+#define ZWP_LINUX_DMABUF_V1_CREATE_PARAMS 1
+
+/**
+ * @ingroup iface_zwp_linux_dmabuf_v1
+ */
+#define ZWP_LINUX_DMABUF_V1_FORMAT_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_linux_dmabuf_v1
+ */
+#define ZWP_LINUX_DMABUF_V1_MODIFIER_SINCE_VERSION 3
+
+/**
+ * @ingroup iface_zwp_linux_dmabuf_v1
+ */
+#define ZWP_LINUX_DMABUF_V1_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_linux_dmabuf_v1
+ */
+#define ZWP_LINUX_DMABUF_V1_CREATE_PARAMS_SINCE_VERSION 1
+
+/** @ingroup iface_zwp_linux_dmabuf_v1 */
+static inline void zwp_linux_dmabuf_v1_set_user_data(
+    struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf_v1, void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)zwp_linux_dmabuf_v1, user_data);
+}
+
+/** @ingroup iface_zwp_linux_dmabuf_v1 */
+static inline void* zwp_linux_dmabuf_v1_get_user_data(
+    struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)zwp_linux_dmabuf_v1);
+}
+
+static inline uint32_t zwp_linux_dmabuf_v1_get_version(
+    struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)zwp_linux_dmabuf_v1);
+}
+
+/**
+ * @ingroup iface_zwp_linux_dmabuf_v1
+ *
+ * Objects created through this interface, especially wl_buffers, will
+ * remain valid.
+ */
+static inline void zwp_linux_dmabuf_v1_destroy(
+    struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf_v1) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_linux_dmabuf_v1,
+                   ZWP_LINUX_DMABUF_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)zwp_linux_dmabuf_v1);
+}
+
+/**
+ * @ingroup iface_zwp_linux_dmabuf_v1
+ *
+ * This temporary object is used to collect multiple dmabuf handles into
+ * a single batch to create a wl_buffer. It can only be used once and
+ * should be destroyed after a 'created' or 'failed' event has been
+ * received.
+ */
+static inline struct zwp_linux_buffer_params_v1*
+zwp_linux_dmabuf_v1_create_params(
+    struct zwp_linux_dmabuf_v1* zwp_linux_dmabuf_v1) {
+  struct wl_proxy* params_id;
+
+  params_id = wl_proxy_marshal_constructor(
+      (struct wl_proxy*)zwp_linux_dmabuf_v1, ZWP_LINUX_DMABUF_V1_CREATE_PARAMS,
+      &zwp_linux_buffer_params_v1_interface, NULL);
+
+  return (struct zwp_linux_buffer_params_v1*)params_id;
+}
+
+#ifndef ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_ENUM
+#  define ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_ENUM
+enum zwp_linux_buffer_params_v1_error {
+  /**
+   * the dmabuf_batch object has already been used to create a wl_buffer
+   */
+  ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_ALREADY_USED = 0,
+  /**
+   * plane index out of bounds
+   */
+  ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_PLANE_IDX = 1,
+  /**
+   * the plane index was already set
+   */
+  ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_PLANE_SET = 2,
+  /**
+   * missing or too many planes to create a buffer
+   */
+  ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_INCOMPLETE = 3,
+  /**
+   * format not supported
+   */
+  ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_INVALID_FORMAT = 4,
+  /**
+   * invalid width or height
+   */
+  ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_INVALID_DIMENSIONS = 5,
+  /**
+   * offset + stride * height goes out of dmabuf bounds
+   */
+  ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_OUT_OF_BOUNDS = 6,
+  /**
+   * invalid wl_buffer resulted from importing dmabufs via                the
+   * create_immed request on given buffer_params
+   */
+  ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_INVALID_WL_BUFFER = 7,
+};
+#endif /* ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_ENUM */
+
+#ifndef ZWP_LINUX_BUFFER_PARAMS_V1_FLAGS_ENUM
+#  define ZWP_LINUX_BUFFER_PARAMS_V1_FLAGS_ENUM
+enum zwp_linux_buffer_params_v1_flags {
+  /**
+   * contents are y-inverted
+   */
+  ZWP_LINUX_BUFFER_PARAMS_V1_FLAGS_Y_INVERT = 1,
+  /**
+   * content is interlaced
+   */
+  ZWP_LINUX_BUFFER_PARAMS_V1_FLAGS_INTERLACED = 2,
+  /**
+   * bottom field first
+   */
+  ZWP_LINUX_BUFFER_PARAMS_V1_FLAGS_BOTTOM_FIRST = 4,
+};
+#endif /* ZWP_LINUX_BUFFER_PARAMS_V1_FLAGS_ENUM */
+
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ * @struct zwp_linux_buffer_params_v1_listener
+ */
+struct zwp_linux_buffer_params_v1_listener {
+  /**
+   * buffer creation succeeded
+   *
+   * This event indicates that the attempted buffer creation was
+   * successful. It provides the new wl_buffer referencing the
+   * dmabuf(s).
+   *
+   * Upon receiving this event, the client should destroy the
+   * zlinux_dmabuf_params object.
+   * @param buffer the newly created wl_buffer
+   */
+  void (*created)(void* data,
+                  struct zwp_linux_buffer_params_v1* zwp_linux_buffer_params_v1,
+                  struct wl_buffer* buffer);
+  /**
+   * buffer creation failed
+   *
+   * This event indicates that the attempted buffer creation has
+   * failed. It usually means that one of the dmabuf constraints has
+   * not been fulfilled.
+   *
+   * Upon receiving this event, the client should destroy the
+   * zlinux_buffer_params object.
+   */
+  void (*failed)(void* data,
+                 struct zwp_linux_buffer_params_v1* zwp_linux_buffer_params_v1);
+};
+
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ */
+static inline int zwp_linux_buffer_params_v1_add_listener(
+    struct zwp_linux_buffer_params_v1* zwp_linux_buffer_params_v1,
+    const struct zwp_linux_buffer_params_v1_listener* listener, void* data) {
+  return wl_proxy_add_listener((struct wl_proxy*)zwp_linux_buffer_params_v1,
+                               (void (**)(void))listener, data);
+}
+
+#define ZWP_LINUX_BUFFER_PARAMS_V1_DESTROY 0
+#define ZWP_LINUX_BUFFER_PARAMS_V1_ADD 1
+#define ZWP_LINUX_BUFFER_PARAMS_V1_CREATE 2
+#define ZWP_LINUX_BUFFER_PARAMS_V1_CREATE_IMMED 3
+
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ */
+#define ZWP_LINUX_BUFFER_PARAMS_V1_CREATED_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ */
+#define ZWP_LINUX_BUFFER_PARAMS_V1_FAILED_SINCE_VERSION 1
+
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ */
+#define ZWP_LINUX_BUFFER_PARAMS_V1_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ */
+#define ZWP_LINUX_BUFFER_PARAMS_V1_ADD_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ */
+#define ZWP_LINUX_BUFFER_PARAMS_V1_CREATE_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ */
+#define ZWP_LINUX_BUFFER_PARAMS_V1_CREATE_IMMED_SINCE_VERSION 2
+
+/** @ingroup iface_zwp_linux_buffer_params_v1 */
+static inline void zwp_linux_buffer_params_v1_set_user_data(
+    struct zwp_linux_buffer_params_v1* zwp_linux_buffer_params_v1,
+    void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)zwp_linux_buffer_params_v1,
+                         user_data);
+}
+
+/** @ingroup iface_zwp_linux_buffer_params_v1 */
+static inline void* zwp_linux_buffer_params_v1_get_user_data(
+    struct zwp_linux_buffer_params_v1* zwp_linux_buffer_params_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)zwp_linux_buffer_params_v1);
+}
+
+static inline uint32_t zwp_linux_buffer_params_v1_get_version(
+    struct zwp_linux_buffer_params_v1* zwp_linux_buffer_params_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)zwp_linux_buffer_params_v1);
+}
+
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ *
+ * Cleans up the temporary data sent to the server for dmabuf-based
+ * wl_buffer creation.
+ */
+static inline void zwp_linux_buffer_params_v1_destroy(
+    struct zwp_linux_buffer_params_v1* zwp_linux_buffer_params_v1) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_linux_buffer_params_v1,
+                   ZWP_LINUX_BUFFER_PARAMS_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)zwp_linux_buffer_params_v1);
+}
+
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ *
+ * This request adds one dmabuf to the set in this
+ * zwp_linux_buffer_params_v1.
+ *
+ * The 64-bit unsigned value combined from modifier_hi and modifier_lo
+ * is the dmabuf layout modifier. DRM AddFB2 ioctl calls this the
+ * fb modifier, which is defined in drm_mode.h of Linux UAPI.
+ * This is an opaque token. Drivers use this token to express tiling,
+ * compression, etc. driver-specific modifications to the base format
+ * defined by the DRM fourcc code.
+ *
+ * This request raises the PLANE_IDX error if plane_idx is too large.
+ * The error PLANE_SET is raised if attempting to set a plane that
+ * was already set.
+ */
+static inline void zwp_linux_buffer_params_v1_add(
+    struct zwp_linux_buffer_params_v1* zwp_linux_buffer_params_v1, int32_t fd,
+    uint32_t plane_idx, uint32_t offset, uint32_t stride, uint32_t modifier_hi,
+    uint32_t modifier_lo) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_linux_buffer_params_v1,
+                   ZWP_LINUX_BUFFER_PARAMS_V1_ADD, fd, plane_idx, offset,
+                   stride, modifier_hi, modifier_lo);
+}
+
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ *
+ * This asks for creation of a wl_buffer from the added dmabuf
+ * buffers. The wl_buffer is not created immediately but returned via
+ * the 'created' event if the dmabuf sharing succeeds. The sharing
+ * may fail at runtime for reasons a client cannot predict, in
+ * which case the 'failed' event is triggered.
+ *
+ * The 'format' argument is a DRM_FORMAT code, as defined by the
+ * libdrm's drm_fourcc.h. The Linux kernel's DRM sub-system is the
+ * authoritative source on how the format codes should work.
+ *
+ * The 'flags' is a bitfield of the flags defined in enum "flags".
+ * 'y_invert' means the that the image needs to be y-flipped.
+ *
+ * Flag 'interlaced' means that the frame in the buffer is not
+ * progressive as usual, but interlaced. An interlaced buffer as
+ * supported here must always contain both top and bottom fields.
+ * The top field always begins on the first pixel row. The temporal
+ * ordering between the two fields is top field first, unless
+ * 'bottom_first' is specified. It is undefined whether 'bottom_first'
+ * is ignored if 'interlaced' is not set.
+ *
+ * This protocol does not convey any information about field rate,
+ * duration, or timing, other than the relative ordering between the
+ * two fields in one buffer. A compositor may have to estimate the
+ * intended field rate from the incoming buffer rate. It is undefined
+ * whether the time of receiving wl_surface.commit with a new buffer
+ * attached, applying the wl_surface state, wl_surface.frame callback
+ * trigger, presentation, or any other point in the compositor cycle
+ * is used to measure the frame or field times. There is no support
+ * for detecting missed or late frames/fields/buffers either, and
+ * there is no support whatsoever for cooperating with interlaced
+ * compositor output.
+ *
+ * The composited image quality resulting from the use of interlaced
+ * buffers is explicitly undefined. A compositor may use elaborate
+ * hardware features or software to deinterlace and create progressive
+ * output frames from a sequence of interlaced input buffers, or it
+ * may produce substandard image quality. However, compositors that
+ * cannot guarantee reasonable image quality in all cases are recommended
+ * to just reject all interlaced buffers.
+ *
+ * Any argument errors, including non-positive width or height,
+ * mismatch between the number of planes and the format, bad
+ * format, bad offset or stride, may be indicated by fatal protocol
+ * errors: INCOMPLETE, INVALID_FORMAT, INVALID_DIMENSIONS,
+ * OUT_OF_BOUNDS.
+ *
+ * Dmabuf import errors in the server that are not obvious client
+ * bugs are returned via the 'failed' event as non-fatal. This
+ * allows attempting dmabuf sharing and falling back in the client
+ * if it fails.
+ *
+ * This request can be sent only once in the object's lifetime, after
+ * which the only legal request is destroy. This object should be
+ * destroyed after issuing a 'create' request. Attempting to use this
+ * object after issuing 'create' raises ALREADY_USED protocol error.
+ *
+ * It is not mandatory to issue 'create'. If a client wants to
+ * cancel the buffer creation, it can just destroy this object.
+ */
+static inline void zwp_linux_buffer_params_v1_create(
+    struct zwp_linux_buffer_params_v1* zwp_linux_buffer_params_v1,
+    int32_t width, int32_t height, uint32_t format, uint32_t flags) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_linux_buffer_params_v1,
+                   ZWP_LINUX_BUFFER_PARAMS_V1_CREATE, width, height, format,
+                   flags);
+}
+
+/**
+ * @ingroup iface_zwp_linux_buffer_params_v1
+ *
+ * This asks for immediate creation of a wl_buffer by importing the
+ * added dmabufs.
+ *
+ * In case of import success, no event is sent from the server, and the
+ * wl_buffer is ready to be used by the client.
+ *
+ * Upon import failure, either of the following may happen, as seen fit
+ * by the implementation:
+ * - the client is terminated with one of the following fatal protocol
+ * errors:
+ * - INCOMPLETE, INVALID_FORMAT, INVALID_DIMENSIONS, OUT_OF_BOUNDS,
+ * in case of argument errors such as mismatch between the number
+ * of planes and the format, bad format, non-positive width or
+ * height, or bad offset or stride.
+ * - INVALID_WL_BUFFER, in case the cause for failure is unknown or
+ * plaform specific.
+ * - the server creates an invalid wl_buffer, marks it as failed and
+ * sends a 'failed' event to the client. The result of using this
+ * invalid wl_buffer as an argument in any request by the client is
+ * defined by the compositor implementation.
+ *
+ * This takes the same arguments as a 'create' request, and obeys the
+ * same restrictions.
+ */
+static inline struct wl_buffer* zwp_linux_buffer_params_v1_create_immed(
+    struct zwp_linux_buffer_params_v1* zwp_linux_buffer_params_v1,
+    int32_t width, int32_t height, uint32_t format, uint32_t flags) {
+  struct wl_proxy* buffer_id;
+
+  buffer_id = wl_proxy_marshal_constructor(
+      (struct wl_proxy*)zwp_linux_buffer_params_v1,
+      ZWP_LINUX_BUFFER_PARAMS_V1_CREATE_IMMED, &wl_buffer_interface, NULL,
+      width, height, format, flags);
+
+  return (struct wl_buffer*)buffer_id;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/widget/gtk/wayland/linux-dmabuf-unstable-v1-protocol.c b/widget/gtk/wayland/linux-dmabuf-unstable-v1-protocol.c
new file mode 100644
index 0000000000..51c1e8e575
--- /dev/null
+++ b/widget/gtk/wayland/linux-dmabuf-unstable-v1-protocol.c
@@ -0,0 +1,81 @@
+/* Generated by wayland-scanner 1.17.0 */
+
+/*
+ * Copyright © 2014, 2015 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include "wayland-util.h"
+
+#pragma GCC visibility push(default)
+extern const struct wl_interface wl_buffer_interface;
+extern const struct wl_interface zwp_linux_buffer_params_v1_interface;
+#pragma GCC visibility pop
+
+static const struct wl_interface* types[] = {
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    &zwp_linux_buffer_params_v1_interface,
+    &wl_buffer_interface,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    &wl_buffer_interface,
+};
+
+static const struct wl_message zwp_linux_dmabuf_v1_requests[] = {
+    {"destroy", "", types + 0},
+    {"create_params", "n", types + 6},
+};
+
+static const struct wl_message zwp_linux_dmabuf_v1_events[] = {
+    {"format", "u", types + 0},
+    {"modifier", "3uuu", types + 0},
+};
+
+const struct wl_interface zwp_linux_dmabuf_v1_interface = {
+    "zwp_linux_dmabuf_v1",        3, 2,
+    zwp_linux_dmabuf_v1_requests, 2, zwp_linux_dmabuf_v1_events,
+};
+
+static const struct wl_message zwp_linux_buffer_params_v1_requests[] = {
+    {"destroy", "", types + 0},
+    {"add", "huuuuu", types + 0},
+    {"create", "iiuu", types + 0},
+    {"create_immed", "2niiuu", types + 7},
+};
+
+static const struct wl_message zwp_linux_buffer_params_v1_events[] = {
+    {"created", "n", types + 12},
+    {"failed", "", types + 0},
+};
+
+const struct wl_interface zwp_linux_buffer_params_v1_interface = {
+    "zwp_linux_buffer_params_v1",        3, 4,
+    zwp_linux_buffer_params_v1_requests, 2, zwp_linux_buffer_params_v1_events,
+};
diff --git a/widget/gtk/wayland/moz.build b/widget/gtk/wayland/moz.build
new file mode 100644
index 0000000000..e033187a3b
--- /dev/null
+++ b/widget/gtk/wayland/moz.build
@@ -0,0 +1,37 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "Widget: Gtk")
+
+SOURCES += [
+    "fractional-scale-v1-protocol.c",
+    "idle-inhibit-unstable-v1-protocol.c",
+    "linux-dmabuf-unstable-v1-protocol.c",
+    "pointer-constraints-unstable-v1-protocol.c",
+    "relative-pointer-unstable-v1-protocol.c",
+    "viewporter-protocol.c",
+    "xdg-activation-v1-protocol.c",
+    "xdg-output-unstable-v1-protocol.c",
+]
+
+EXPORTS.mozilla.widget += [
+    "fractional-scale-v1-client-protocol.h",
+    "idle-inhibit-unstable-v1-client-protocol.h",
+    "linux-dmabuf-unstable-v1-client-protocol.h",
+    "pointer-constraints-unstable-v1-client-protocol.h",
+    "relative-pointer-unstable-v1-client-protocol.h",
+    "viewporter-client-protocol.h",
+    "xdg-activation-v1-client-protocol.h",
+    "xdg-output-unstable-v1-client-protocol.h",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
+
+CFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
+CXXFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
diff --git a/widget/gtk/wayland/pointer-constraints-unstable-v1-client-protocol.h b/widget/gtk/wayland/pointer-constraints-unstable-v1-client-protocol.h
new file mode 100644
index 0000000000..0f38dee226
--- /dev/null
+++ b/widget/gtk/wayland/pointer-constraints-unstable-v1-client-protocol.h
@@ -0,0 +1,650 @@
+/* Generated by wayland-scanner 1.18.0 */
+
+#ifndef POINTER_CONSTRAINTS_UNSTABLE_V1_CLIENT_PROTOCOL_H
+#define POINTER_CONSTRAINTS_UNSTABLE_V1_CLIENT_PROTOCOL_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include "wayland-client.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @page page_pointer_constraints_unstable_v1 The
+ * pointer_constraints_unstable_v1 protocol protocol for constraining pointer
+ * motions
+ *
+ * @section page_desc_pointer_constraints_unstable_v1 Description
+ *
+ * This protocol specifies a set of interfaces used for adding constraints to
+ * the motion of a pointer. Possible constraints include confining pointer
+ * motions to a given region, or locking it to its current position.
+ *
+ * In order to constrain the pointer, a client must first bind the global
+ * interface "wp_pointer_constraints" which, if a compositor supports pointer
+ * constraints, is exposed by the registry. Using the bound global object, the
+ * client uses the request that corresponds to the type of constraint it wants
+ * to make. See wp_pointer_constraints for more details.
+ *
+ * Warning! The protocol described in this file is experimental and backward
+ * incompatible changes may be made. Backward compatible changes may be added
+ * together with the corresponding interface version bump. Backward
+ * incompatible changes are done by bumping the version number in the protocol
+ * and interface names and resetting the interface version. Once the protocol
+ * is to be declared stable, the 'z' prefix and the version number in the
+ * protocol and interface names are removed and the interface version number is
+ * reset.
+ *
+ * @section page_ifaces_pointer_constraints_unstable_v1 Interfaces
+ * - @subpage page_iface_zwp_pointer_constraints_v1 - constrain the movement of
+ * a pointer
+ * - @subpage page_iface_zwp_locked_pointer_v1 - receive relative pointer motion
+ * events
+ * - @subpage page_iface_zwp_confined_pointer_v1 - confined pointer object
+ * @section page_copyright_pointer_constraints_unstable_v1 Copyright
+ * <pre>
+ *
+ * Copyright © 2014      Jonas Ådahl
+ * Copyright © 2015      Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ * </pre>
+ */
+struct wl_pointer;
+struct wl_region;
+struct wl_surface;
+struct zwp_confined_pointer_v1;
+struct zwp_locked_pointer_v1;
+struct zwp_pointer_constraints_v1;
+
+/**
+ * @page page_iface_zwp_pointer_constraints_v1 zwp_pointer_constraints_v1
+ * @section page_iface_zwp_pointer_constraints_v1_desc Description
+ *
+ * The global interface exposing pointer constraining functionality. It
+ * exposes two requests: lock_pointer for locking the pointer to its
+ * position, and confine_pointer for locking the pointer to a region.
+ *
+ * The lock_pointer and confine_pointer requests create the objects
+ * wp_locked_pointer and wp_confined_pointer respectively, and the client can
+ * use these objects to interact with the lock.
+ *
+ * For any surface, only one lock or confinement may be active across all
+ * wl_pointer objects of the same seat. If a lock or confinement is requested
+ * when another lock or confinement is active or requested on the same surface
+ * and with any of the wl_pointer objects of the same seat, an
+ * 'already_constrained' error will be raised.
+ * @section page_iface_zwp_pointer_constraints_v1_api API
+ * See @ref iface_zwp_pointer_constraints_v1.
+ */
+/**
+ * @defgroup iface_zwp_pointer_constraints_v1 The zwp_pointer_constraints_v1
+ * interface
+ *
+ * The global interface exposing pointer constraining functionality. It
+ * exposes two requests: lock_pointer for locking the pointer to its
+ * position, and confine_pointer for locking the pointer to a region.
+ *
+ * The lock_pointer and confine_pointer requests create the objects
+ * wp_locked_pointer and wp_confined_pointer respectively, and the client can
+ * use these objects to interact with the lock.
+ *
+ * For any surface, only one lock or confinement may be active across all
+ * wl_pointer objects of the same seat. If a lock or confinement is requested
+ * when another lock or confinement is active or requested on the same surface
+ * and with any of the wl_pointer objects of the same seat, an
+ * 'already_constrained' error will be raised.
+ */
+extern const struct wl_interface zwp_pointer_constraints_v1_interface;
+/**
+ * @page page_iface_zwp_locked_pointer_v1 zwp_locked_pointer_v1
+ * @section page_iface_zwp_locked_pointer_v1_desc Description
+ *
+ * The wp_locked_pointer interface represents a locked pointer state.
+ *
+ * While the lock of this object is active, the wl_pointer objects of the
+ * associated seat will not emit any wl_pointer.motion events.
+ *
+ * This object will send the event 'locked' when the lock is activated.
+ * Whenever the lock is activated, it is guaranteed that the locked surface
+ * will already have received pointer focus and that the pointer will be
+ * within the region passed to the request creating this object.
+ *
+ * To unlock the pointer, send the destroy request. This will also destroy
+ * the wp_locked_pointer object.
+ *
+ * If the compositor decides to unlock the pointer the unlocked event is
+ * sent. See wp_locked_pointer.unlock for details.
+ *
+ * When unlocking, the compositor may warp the cursor position to the set
+ * cursor position hint. If it does, it will not result in any relative
+ * motion events emitted via wp_relative_pointer.
+ *
+ * If the surface the lock was requested on is destroyed and the lock is not
+ * yet activated, the wp_locked_pointer object is now defunct and must be
+ * destroyed.
+ * @section page_iface_zwp_locked_pointer_v1_api API
+ * See @ref iface_zwp_locked_pointer_v1.
+ */
+/**
+ * @defgroup iface_zwp_locked_pointer_v1 The zwp_locked_pointer_v1 interface
+ *
+ * The wp_locked_pointer interface represents a locked pointer state.
+ *
+ * While the lock of this object is active, the wl_pointer objects of the
+ * associated seat will not emit any wl_pointer.motion events.
+ *
+ * This object will send the event 'locked' when the lock is activated.
+ * Whenever the lock is activated, it is guaranteed that the locked surface
+ * will already have received pointer focus and that the pointer will be
+ * within the region passed to the request creating this object.
+ *
+ * To unlock the pointer, send the destroy request. This will also destroy
+ * the wp_locked_pointer object.
+ *
+ * If the compositor decides to unlock the pointer the unlocked event is
+ * sent. See wp_locked_pointer.unlock for details.
+ *
+ * When unlocking, the compositor may warp the cursor position to the set
+ * cursor position hint. If it does, it will not result in any relative
+ * motion events emitted via wp_relative_pointer.
+ *
+ * If the surface the lock was requested on is destroyed and the lock is not
+ * yet activated, the wp_locked_pointer object is now defunct and must be
+ * destroyed.
+ */
+extern const struct wl_interface zwp_locked_pointer_v1_interface;
+/**
+ * @page page_iface_zwp_confined_pointer_v1 zwp_confined_pointer_v1
+ * @section page_iface_zwp_confined_pointer_v1_desc Description
+ *
+ * The wp_confined_pointer interface represents a confined pointer state.
+ *
+ * This object will send the event 'confined' when the confinement is
+ * activated. Whenever the confinement is activated, it is guaranteed that
+ * the surface the pointer is confined to will already have received pointer
+ * focus and that the pointer will be within the region passed to the request
+ * creating this object. It is up to the compositor to decide whether this
+ * requires some user interaction and if the pointer will warp to within the
+ * passed region if outside.
+ *
+ * To unconfine the pointer, send the destroy request. This will also destroy
+ * the wp_confined_pointer object.
+ *
+ * If the compositor decides to unconfine the pointer the unconfined event is
+ * sent. The wp_confined_pointer object is at this point defunct and should
+ * be destroyed.
+ * @section page_iface_zwp_confined_pointer_v1_api API
+ * See @ref iface_zwp_confined_pointer_v1.
+ */
+/**
+ * @defgroup iface_zwp_confined_pointer_v1 The zwp_confined_pointer_v1 interface
+ *
+ * The wp_confined_pointer interface represents a confined pointer state.
+ *
+ * This object will send the event 'confined' when the confinement is
+ * activated. Whenever the confinement is activated, it is guaranteed that
+ * the surface the pointer is confined to will already have received pointer
+ * focus and that the pointer will be within the region passed to the request
+ * creating this object. It is up to the compositor to decide whether this
+ * requires some user interaction and if the pointer will warp to within the
+ * passed region if outside.
+ *
+ * To unconfine the pointer, send the destroy request. This will also destroy
+ * the wp_confined_pointer object.
+ *
+ * If the compositor decides to unconfine the pointer the unconfined event is
+ * sent. The wp_confined_pointer object is at this point defunct and should
+ * be destroyed.
+ */
+extern const struct wl_interface zwp_confined_pointer_v1_interface;
+
+#ifndef ZWP_POINTER_CONSTRAINTS_V1_ERROR_ENUM
+#  define ZWP_POINTER_CONSTRAINTS_V1_ERROR_ENUM
+/**
+ * @ingroup iface_zwp_pointer_constraints_v1
+ * wp_pointer_constraints error values
+ *
+ * These errors can be emitted in response to wp_pointer_constraints
+ * requests.
+ */
+enum zwp_pointer_constraints_v1_error {
+  /**
+   * pointer constraint already requested on that surface
+   */
+  ZWP_POINTER_CONSTRAINTS_V1_ERROR_ALREADY_CONSTRAINED = 1,
+};
+#endif /* ZWP_POINTER_CONSTRAINTS_V1_ERROR_ENUM */
+
+#ifndef ZWP_POINTER_CONSTRAINTS_V1_LIFETIME_ENUM
+#  define ZWP_POINTER_CONSTRAINTS_V1_LIFETIME_ENUM
+/**
+ * @ingroup iface_zwp_pointer_constraints_v1
+ * the pointer constraint may reactivate
+ *
+ * A persistent pointer constraint may again reactivate once it has
+ * been deactivated. See the corresponding deactivation event
+ * (wp_locked_pointer.unlocked and wp_confined_pointer.unconfined) for
+ * details.
+ */
+enum zwp_pointer_constraints_v1_lifetime {
+  ZWP_POINTER_CONSTRAINTS_V1_LIFETIME_ONESHOT = 1,
+  ZWP_POINTER_CONSTRAINTS_V1_LIFETIME_PERSISTENT = 2,
+};
+#endif /* ZWP_POINTER_CONSTRAINTS_V1_LIFETIME_ENUM */
+
+#define ZWP_POINTER_CONSTRAINTS_V1_DESTROY 0
+#define ZWP_POINTER_CONSTRAINTS_V1_LOCK_POINTER 1
+#define ZWP_POINTER_CONSTRAINTS_V1_CONFINE_POINTER 2
+
+/**
+ * @ingroup iface_zwp_pointer_constraints_v1
+ */
+#define ZWP_POINTER_CONSTRAINTS_V1_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_pointer_constraints_v1
+ */
+#define ZWP_POINTER_CONSTRAINTS_V1_LOCK_POINTER_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_pointer_constraints_v1
+ */
+#define ZWP_POINTER_CONSTRAINTS_V1_CONFINE_POINTER_SINCE_VERSION 1
+
+/** @ingroup iface_zwp_pointer_constraints_v1 */
+static inline void zwp_pointer_constraints_v1_set_user_data(
+    struct zwp_pointer_constraints_v1* zwp_pointer_constraints_v1,
+    void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)zwp_pointer_constraints_v1,
+                         user_data);
+}
+
+/** @ingroup iface_zwp_pointer_constraints_v1 */
+static inline void* zwp_pointer_constraints_v1_get_user_data(
+    struct zwp_pointer_constraints_v1* zwp_pointer_constraints_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)zwp_pointer_constraints_v1);
+}
+
+static inline uint32_t zwp_pointer_constraints_v1_get_version(
+    struct zwp_pointer_constraints_v1* zwp_pointer_constraints_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)zwp_pointer_constraints_v1);
+}
+
+/**
+ * @ingroup iface_zwp_pointer_constraints_v1
+ *
+ * Used by the client to notify the server that it will no longer use this
+ * pointer constraints object.
+ */
+static inline void zwp_pointer_constraints_v1_destroy(
+    struct zwp_pointer_constraints_v1* zwp_pointer_constraints_v1) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_pointer_constraints_v1,
+                   ZWP_POINTER_CONSTRAINTS_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)zwp_pointer_constraints_v1);
+}
+
+/**
+ * @ingroup iface_zwp_pointer_constraints_v1
+ *
+ * The lock_pointer request lets the client request to disable movements of
+ * the virtual pointer (i.e. the cursor), effectively locking the pointer
+ * to a position. This request may not take effect immediately; in the
+ * future, when the compositor deems implementation-specific constraints
+ * are satisfied, the pointer lock will be activated and the compositor
+ * sends a locked event.
+ *
+ * The protocol provides no guarantee that the constraints are ever
+ * satisfied, and does not require the compositor to send an error if the
+ * constraints cannot ever be satisfied. It is thus possible to request a
+ * lock that will never activate.
+ *
+ * There may not be another pointer constraint of any kind requested or
+ * active on the surface for any of the wl_pointer objects of the seat of
+ * the passed pointer when requesting a lock. If there is, an error will be
+ * raised. See general pointer lock documentation for more details.
+ *
+ * The intersection of the region passed with this request and the input
+ * region of the surface is used to determine where the pointer must be
+ * in order for the lock to activate. It is up to the compositor whether to
+ * warp the pointer or require some kind of user interaction for the lock
+ * to activate. If the region is null the surface input region is used.
+ *
+ * A surface may receive pointer focus without the lock being activated.
+ *
+ * The request creates a new object wp_locked_pointer which is used to
+ * interact with the lock as well as receive updates about its state. See
+ * the the description of wp_locked_pointer for further information.
+ *
+ * Note that while a pointer is locked, the wl_pointer objects of the
+ * corresponding seat will not emit any wl_pointer.motion events, but
+ * relative motion events will still be emitted via wp_relative_pointer
+ * objects of the same seat. wl_pointer.axis and wl_pointer.button events
+ * are unaffected.
+ */
+static inline struct zwp_locked_pointer_v1*
+zwp_pointer_constraints_v1_lock_pointer(
+    struct zwp_pointer_constraints_v1* zwp_pointer_constraints_v1,
+    struct wl_surface* surface, struct wl_pointer* pointer,
+    struct wl_region* region, uint32_t lifetime) {
+  struct wl_proxy* id;
+
+  id = wl_proxy_marshal_constructor(
+      (struct wl_proxy*)zwp_pointer_constraints_v1,
+      ZWP_POINTER_CONSTRAINTS_V1_LOCK_POINTER, &zwp_locked_pointer_v1_interface,
+      NULL, surface, pointer, region, lifetime);
+
+  return (struct zwp_locked_pointer_v1*)id;
+}
+
+/**
+ * @ingroup iface_zwp_pointer_constraints_v1
+ *
+ * The confine_pointer request lets the client request to confine the
+ * pointer cursor to a given region. This request may not take effect
+ * immediately; in the future, when the compositor deems implementation-
+ * specific constraints are satisfied, the pointer confinement will be
+ * activated and the compositor sends a confined event.
+ *
+ * The intersection of the region passed with this request and the input
+ * region of the surface is used to determine where the pointer must be
+ * in order for the confinement to activate. It is up to the compositor
+ * whether to warp the pointer or require some kind of user interaction for
+ * the confinement to activate. If the region is null the surface input
+ * region is used.
+ *
+ * The request will create a new object wp_confined_pointer which is used
+ * to interact with the confinement as well as receive updates about its
+ * state. See the the description of wp_confined_pointer for further
+ * information.
+ */
+static inline struct zwp_confined_pointer_v1*
+zwp_pointer_constraints_v1_confine_pointer(
+    struct zwp_pointer_constraints_v1* zwp_pointer_constraints_v1,
+    struct wl_surface* surface, struct wl_pointer* pointer,
+    struct wl_region* region, uint32_t lifetime) {
+  struct wl_proxy* id;
+
+  id =
+      wl_proxy_marshal_constructor((struct wl_proxy*)zwp_pointer_constraints_v1,
+                                   ZWP_POINTER_CONSTRAINTS_V1_CONFINE_POINTER,
+                                   &zwp_confined_pointer_v1_interface, NULL,
+                                   surface, pointer, region, lifetime);
+
+  return (struct zwp_confined_pointer_v1*)id;
+}
+
+/**
+ * @ingroup iface_zwp_locked_pointer_v1
+ * @struct zwp_locked_pointer_v1_listener
+ */
+struct zwp_locked_pointer_v1_listener {
+  /**
+   * lock activation event
+   *
+   * Notification that the pointer lock of the seat's pointer is
+   * activated.
+   */
+  void (*locked)(void* data,
+                 struct zwp_locked_pointer_v1* zwp_locked_pointer_v1);
+  /**
+   * lock deactivation event
+   *
+   * Notification that the pointer lock of the seat's pointer is no
+   * longer active. If this is a oneshot pointer lock (see
+   * wp_pointer_constraints.lifetime) this object is now defunct and
+   * should be destroyed. If this is a persistent pointer lock (see
+   * wp_pointer_constraints.lifetime) this pointer lock may again
+   * reactivate in the future.
+   */
+  void (*unlocked)(void* data,
+                   struct zwp_locked_pointer_v1* zwp_locked_pointer_v1);
+};
+
+/**
+ * @ingroup iface_zwp_locked_pointer_v1
+ */
+static inline int zwp_locked_pointer_v1_add_listener(
+    struct zwp_locked_pointer_v1* zwp_locked_pointer_v1,
+    const struct zwp_locked_pointer_v1_listener* listener, void* data) {
+  return wl_proxy_add_listener((struct wl_proxy*)zwp_locked_pointer_v1,
+                               (void (**)(void))listener, data);
+}
+
+#define ZWP_LOCKED_POINTER_V1_DESTROY 0
+#define ZWP_LOCKED_POINTER_V1_SET_CURSOR_POSITION_HINT 1
+#define ZWP_LOCKED_POINTER_V1_SET_REGION 2
+
+/**
+ * @ingroup iface_zwp_locked_pointer_v1
+ */
+#define ZWP_LOCKED_POINTER_V1_LOCKED_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_locked_pointer_v1
+ */
+#define ZWP_LOCKED_POINTER_V1_UNLOCKED_SINCE_VERSION 1
+
+/**
+ * @ingroup iface_zwp_locked_pointer_v1
+ */
+#define ZWP_LOCKED_POINTER_V1_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_locked_pointer_v1
+ */
+#define ZWP_LOCKED_POINTER_V1_SET_CURSOR_POSITION_HINT_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_locked_pointer_v1
+ */
+#define ZWP_LOCKED_POINTER_V1_SET_REGION_SINCE_VERSION 1
+
+/** @ingroup iface_zwp_locked_pointer_v1 */
+static inline void zwp_locked_pointer_v1_set_user_data(
+    struct zwp_locked_pointer_v1* zwp_locked_pointer_v1, void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)zwp_locked_pointer_v1, user_data);
+}
+
+/** @ingroup iface_zwp_locked_pointer_v1 */
+static inline void* zwp_locked_pointer_v1_get_user_data(
+    struct zwp_locked_pointer_v1* zwp_locked_pointer_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)zwp_locked_pointer_v1);
+}
+
+static inline uint32_t zwp_locked_pointer_v1_get_version(
+    struct zwp_locked_pointer_v1* zwp_locked_pointer_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)zwp_locked_pointer_v1);
+}
+
+/**
+ * @ingroup iface_zwp_locked_pointer_v1
+ *
+ * Destroy the locked pointer object. If applicable, the compositor will
+ * unlock the pointer.
+ */
+static inline void zwp_locked_pointer_v1_destroy(
+    struct zwp_locked_pointer_v1* zwp_locked_pointer_v1) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_locked_pointer_v1,
+                   ZWP_LOCKED_POINTER_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)zwp_locked_pointer_v1);
+}
+
+/**
+ * @ingroup iface_zwp_locked_pointer_v1
+ *
+ * Set the cursor position hint relative to the top left corner of the
+ * surface.
+ *
+ * If the client is drawing its own cursor, it should update the position
+ * hint to the position of its own cursor. A compositor may use this
+ * information to warp the pointer upon unlock in order to avoid pointer
+ * jumps.
+ *
+ * The cursor position hint is double buffered. The new hint will only take
+ * effect when the associated surface gets it pending state applied. See
+ * wl_surface.commit for details.
+ */
+static inline void zwp_locked_pointer_v1_set_cursor_position_hint(
+    struct zwp_locked_pointer_v1* zwp_locked_pointer_v1, wl_fixed_t surface_x,
+    wl_fixed_t surface_y) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_locked_pointer_v1,
+                   ZWP_LOCKED_POINTER_V1_SET_CURSOR_POSITION_HINT, surface_x,
+                   surface_y);
+}
+
+/**
+ * @ingroup iface_zwp_locked_pointer_v1
+ *
+ * Set a new region used to lock the pointer.
+ *
+ * The new lock region is double-buffered. The new lock region will
+ * only take effect when the associated surface gets its pending state
+ * applied. See wl_surface.commit for details.
+ *
+ * For details about the lock region, see wp_locked_pointer.
+ */
+static inline void zwp_locked_pointer_v1_set_region(
+    struct zwp_locked_pointer_v1* zwp_locked_pointer_v1,
+    struct wl_region* region) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_locked_pointer_v1,
+                   ZWP_LOCKED_POINTER_V1_SET_REGION, region);
+}
+
+/**
+ * @ingroup iface_zwp_confined_pointer_v1
+ * @struct zwp_confined_pointer_v1_listener
+ */
+struct zwp_confined_pointer_v1_listener {
+  /**
+   * pointer confined
+   *
+   * Notification that the pointer confinement of the seat's
+   * pointer is activated.
+   */
+  void (*confined)(void* data,
+                   struct zwp_confined_pointer_v1* zwp_confined_pointer_v1);
+  /**
+   * pointer unconfined
+   *
+   * Notification that the pointer confinement of the seat's
+   * pointer is no longer active. If this is a oneshot pointer
+   * confinement (see wp_pointer_constraints.lifetime) this object is
+   * now defunct and should be destroyed. If this is a persistent
+   * pointer confinement (see wp_pointer_constraints.lifetime) this
+   * pointer confinement may again reactivate in the future.
+   */
+  void (*unconfined)(void* data,
+                     struct zwp_confined_pointer_v1* zwp_confined_pointer_v1);
+};
+
+/**
+ * @ingroup iface_zwp_confined_pointer_v1
+ */
+static inline int zwp_confined_pointer_v1_add_listener(
+    struct zwp_confined_pointer_v1* zwp_confined_pointer_v1,
+    const struct zwp_confined_pointer_v1_listener* listener, void* data) {
+  return wl_proxy_add_listener((struct wl_proxy*)zwp_confined_pointer_v1,
+                               (void (**)(void))listener, data);
+}
+
+#define ZWP_CONFINED_POINTER_V1_DESTROY 0
+#define ZWP_CONFINED_POINTER_V1_SET_REGION 1
+
+/**
+ * @ingroup iface_zwp_confined_pointer_v1
+ */
+#define ZWP_CONFINED_POINTER_V1_CONFINED_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_confined_pointer_v1
+ */
+#define ZWP_CONFINED_POINTER_V1_UNCONFINED_SINCE_VERSION 1
+
+/**
+ * @ingroup iface_zwp_confined_pointer_v1
+ */
+#define ZWP_CONFINED_POINTER_V1_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_confined_pointer_v1
+ */
+#define ZWP_CONFINED_POINTER_V1_SET_REGION_SINCE_VERSION 1
+
+/** @ingroup iface_zwp_confined_pointer_v1 */
+static inline void zwp_confined_pointer_v1_set_user_data(
+    struct zwp_confined_pointer_v1* zwp_confined_pointer_v1, void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)zwp_confined_pointer_v1, user_data);
+}
+
+/** @ingroup iface_zwp_confined_pointer_v1 */
+static inline void* zwp_confined_pointer_v1_get_user_data(
+    struct zwp_confined_pointer_v1* zwp_confined_pointer_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)zwp_confined_pointer_v1);
+}
+
+static inline uint32_t zwp_confined_pointer_v1_get_version(
+    struct zwp_confined_pointer_v1* zwp_confined_pointer_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)zwp_confined_pointer_v1);
+}
+
+/**
+ * @ingroup iface_zwp_confined_pointer_v1
+ *
+ * Destroy the confined pointer object. If applicable, the compositor will
+ * unconfine the pointer.
+ */
+static inline void zwp_confined_pointer_v1_destroy(
+    struct zwp_confined_pointer_v1* zwp_confined_pointer_v1) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_confined_pointer_v1,
+                   ZWP_CONFINED_POINTER_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)zwp_confined_pointer_v1);
+}
+
+/**
+ * @ingroup iface_zwp_confined_pointer_v1
+ *
+ * Set a new region used to confine the pointer.
+ *
+ * The new confine region is double-buffered. The new confine region will
+ * only take effect when the associated surface gets its pending state
+ * applied. See wl_surface.commit for details.
+ *
+ * If the confinement is active when the new confinement region is applied
+ * and the pointer ends up outside of newly applied region, the pointer may
+ * warped to a position within the new confinement region. If warped, a
+ * wl_pointer.motion event will be emitted, but no
+ * wp_relative_pointer.relative_motion event.
+ *
+ * The compositor may also, instead of using the new region, unconfine the
+ * pointer.
+ *
+ * For details about the confine region, see wp_confined_pointer.
+ */
+static inline void zwp_confined_pointer_v1_set_region(
+    struct zwp_confined_pointer_v1* zwp_confined_pointer_v1,
+    struct wl_region* region) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_confined_pointer_v1,
+                   ZWP_CONFINED_POINTER_V1_SET_REGION, region);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/widget/gtk/wayland/pointer-constraints-unstable-v1-protocol.c b/widget/gtk/wayland/pointer-constraints-unstable-v1-protocol.c
new file mode 100644
index 0000000000..c28ddf6918
--- /dev/null
+++ b/widget/gtk/wayland/pointer-constraints-unstable-v1-protocol.c
@@ -0,0 +1,97 @@
+/* Generated by wayland-scanner 1.18.0 */
+
+/*
+ * Copyright © 2014      Jonas Ådahl
+ * Copyright © 2015      Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include "wayland-util.h"
+
+#pragma GCC visibility push(default)
+extern const struct wl_interface wl_pointer_interface;
+extern const struct wl_interface wl_region_interface;
+extern const struct wl_interface wl_surface_interface;
+extern const struct wl_interface zwp_confined_pointer_v1_interface;
+extern const struct wl_interface zwp_locked_pointer_v1_interface;
+#pragma GCC visibility pop
+
+static const struct wl_interface* pointer_constraints_unstable_v1_types[] = {
+    NULL,
+    NULL,
+    &zwp_locked_pointer_v1_interface,
+    &wl_surface_interface,
+    &wl_pointer_interface,
+    &wl_region_interface,
+    NULL,
+    &zwp_confined_pointer_v1_interface,
+    &wl_surface_interface,
+    &wl_pointer_interface,
+    &wl_region_interface,
+    NULL,
+    &wl_region_interface,
+    &wl_region_interface,
+};
+
+static const struct wl_message zwp_pointer_constraints_v1_requests[] = {
+    {"destroy", "", pointer_constraints_unstable_v1_types + 0},
+    {"lock_pointer", "noo?ou", pointer_constraints_unstable_v1_types + 2},
+    {"confine_pointer", "noo?ou", pointer_constraints_unstable_v1_types + 7},
+};
+
+WL_EXPORT const struct wl_interface zwp_pointer_constraints_v1_interface = {
+    "zwp_pointer_constraints_v1",        1, 3,
+    zwp_pointer_constraints_v1_requests, 0, NULL,
+};
+
+static const struct wl_message zwp_locked_pointer_v1_requests[] = {
+    {"destroy", "", pointer_constraints_unstable_v1_types + 0},
+    {"set_cursor_position_hint", "ff",
+     pointer_constraints_unstable_v1_types + 0},
+    {"set_region", "?o", pointer_constraints_unstable_v1_types + 12},
+};
+
+static const struct wl_message zwp_locked_pointer_v1_events[] = {
+    {"locked", "", pointer_constraints_unstable_v1_types + 0},
+    {"unlocked", "", pointer_constraints_unstable_v1_types + 0},
+};
+
+WL_EXPORT const struct wl_interface zwp_locked_pointer_v1_interface = {
+    "zwp_locked_pointer_v1",        1, 3,
+    zwp_locked_pointer_v1_requests, 2, zwp_locked_pointer_v1_events,
+};
+
+static const struct wl_message zwp_confined_pointer_v1_requests[] = {
+    {"destroy", "", pointer_constraints_unstable_v1_types + 0},
+    {"set_region", "?o", pointer_constraints_unstable_v1_types + 13},
+};
+
+static const struct wl_message zwp_confined_pointer_v1_events[] = {
+    {"confined", "", pointer_constraints_unstable_v1_types + 0},
+    {"unconfined", "", pointer_constraints_unstable_v1_types + 0},
+};
+
+WL_EXPORT const struct wl_interface zwp_confined_pointer_v1_interface = {
+    "zwp_confined_pointer_v1",        1, 2,
+    zwp_confined_pointer_v1_requests, 2, zwp_confined_pointer_v1_events,
+};
diff --git a/widget/gtk/wayland/relative-pointer-unstable-v1-client-protocol.h b/widget/gtk/wayland/relative-pointer-unstable-v1-client-protocol.h
new file mode 100644
index 0000000000..dbae8081f4
--- /dev/null
+++ b/widget/gtk/wayland/relative-pointer-unstable-v1-client-protocol.h
@@ -0,0 +1,293 @@
+/* Generated by wayland-scanner 1.18.0 */
+
+#ifndef RELATIVE_POINTER_UNSTABLE_V1_CLIENT_PROTOCOL_H
+#define RELATIVE_POINTER_UNSTABLE_V1_CLIENT_PROTOCOL_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include "wayland-client.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @page page_relative_pointer_unstable_v1 The relative_pointer_unstable_v1
+ * protocol protocol for relative pointer motion events
+ *
+ * @section page_desc_relative_pointer_unstable_v1 Description
+ *
+ * This protocol specifies a set of interfaces used for making clients able to
+ * receive relative pointer events not obstructed by barriers (such as the
+ * monitor edge or other pointer barriers).
+ *
+ * To start receiving relative pointer events, a client must first bind the
+ * global interface "wp_relative_pointer_manager" which, if a compositor
+ * supports relative pointer motion events, is exposed by the registry. After
+ * having created the relative pointer manager proxy object, the client uses
+ * it to create the actual relative pointer object using the
+ * "get_relative_pointer" request given a wl_pointer. The relative pointer
+ * motion events will then, when applicable, be transmitted via the proxy of
+ * the newly created relative pointer object. See the documentation of the
+ * relative pointer interface for more details.
+ *
+ * Warning! The protocol described in this file is experimental and backward
+ * incompatible changes may be made. Backward compatible changes may be added
+ * together with the corresponding interface version bump. Backward
+ * incompatible changes are done by bumping the version number in the protocol
+ * and interface names and resetting the interface version. Once the protocol
+ * is to be declared stable, the 'z' prefix and the version number in the
+ * protocol and interface names are removed and the interface version number is
+ * reset.
+ *
+ * @section page_ifaces_relative_pointer_unstable_v1 Interfaces
+ * - @subpage page_iface_zwp_relative_pointer_manager_v1 - get relative pointer
+ * objects
+ * - @subpage page_iface_zwp_relative_pointer_v1 - relative pointer object
+ * @section page_copyright_relative_pointer_unstable_v1 Copyright
+ * <pre>
+ *
+ * Copyright © 2014      Jonas Ådahl
+ * Copyright © 2015      Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ * </pre>
+ */
+struct wl_pointer;
+struct zwp_relative_pointer_manager_v1;
+struct zwp_relative_pointer_v1;
+
+/**
+ * @page page_iface_zwp_relative_pointer_manager_v1
+ * zwp_relative_pointer_manager_v1
+ * @section page_iface_zwp_relative_pointer_manager_v1_desc Description
+ *
+ * A global interface used for getting the relative pointer object for a
+ * given pointer.
+ * @section page_iface_zwp_relative_pointer_manager_v1_api API
+ * See @ref iface_zwp_relative_pointer_manager_v1.
+ */
+/**
+ * @defgroup iface_zwp_relative_pointer_manager_v1 The
+ * zwp_relative_pointer_manager_v1 interface
+ *
+ * A global interface used for getting the relative pointer object for a
+ * given pointer.
+ */
+extern const struct wl_interface zwp_relative_pointer_manager_v1_interface;
+/**
+ * @page page_iface_zwp_relative_pointer_v1 zwp_relative_pointer_v1
+ * @section page_iface_zwp_relative_pointer_v1_desc Description
+ *
+ * A wp_relative_pointer object is an extension to the wl_pointer interface
+ * used for emitting relative pointer events. It shares the same focus as
+ * wl_pointer objects of the same seat and will only emit events when it has
+ * focus.
+ * @section page_iface_zwp_relative_pointer_v1_api API
+ * See @ref iface_zwp_relative_pointer_v1.
+ */
+/**
+ * @defgroup iface_zwp_relative_pointer_v1 The zwp_relative_pointer_v1 interface
+ *
+ * A wp_relative_pointer object is an extension to the wl_pointer interface
+ * used for emitting relative pointer events. It shares the same focus as
+ * wl_pointer objects of the same seat and will only emit events when it has
+ * focus.
+ */
+extern const struct wl_interface zwp_relative_pointer_v1_interface;
+
+#define ZWP_RELATIVE_POINTER_MANAGER_V1_DESTROY 0
+#define ZWP_RELATIVE_POINTER_MANAGER_V1_GET_RELATIVE_POINTER 1
+
+/**
+ * @ingroup iface_zwp_relative_pointer_manager_v1
+ */
+#define ZWP_RELATIVE_POINTER_MANAGER_V1_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_zwp_relative_pointer_manager_v1
+ */
+#define ZWP_RELATIVE_POINTER_MANAGER_V1_GET_RELATIVE_POINTER_SINCE_VERSION 1
+
+/** @ingroup iface_zwp_relative_pointer_manager_v1 */
+static inline void zwp_relative_pointer_manager_v1_set_user_data(
+    struct zwp_relative_pointer_manager_v1* zwp_relative_pointer_manager_v1,
+    void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)zwp_relative_pointer_manager_v1,
+                         user_data);
+}
+
+/** @ingroup iface_zwp_relative_pointer_manager_v1 */
+static inline void* zwp_relative_pointer_manager_v1_get_user_data(
+    struct zwp_relative_pointer_manager_v1* zwp_relative_pointer_manager_v1) {
+  return wl_proxy_get_user_data(
+      (struct wl_proxy*)zwp_relative_pointer_manager_v1);
+}
+
+static inline uint32_t zwp_relative_pointer_manager_v1_get_version(
+    struct zwp_relative_pointer_manager_v1* zwp_relative_pointer_manager_v1) {
+  return wl_proxy_get_version(
+      (struct wl_proxy*)zwp_relative_pointer_manager_v1);
+}
+
+/**
+ * @ingroup iface_zwp_relative_pointer_manager_v1
+ *
+ * Used by the client to notify the server that it will no longer use this
+ * relative pointer manager object.
+ */
+static inline void zwp_relative_pointer_manager_v1_destroy(
+    struct zwp_relative_pointer_manager_v1* zwp_relative_pointer_manager_v1) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_relative_pointer_manager_v1,
+                   ZWP_RELATIVE_POINTER_MANAGER_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)zwp_relative_pointer_manager_v1);
+}
+
+/**
+ * @ingroup iface_zwp_relative_pointer_manager_v1
+ *
+ * Create a relative pointer interface given a wl_pointer object. See the
+ * wp_relative_pointer interface for more details.
+ */
+static inline struct zwp_relative_pointer_v1*
+zwp_relative_pointer_manager_v1_get_relative_pointer(
+    struct zwp_relative_pointer_manager_v1* zwp_relative_pointer_manager_v1,
+    struct wl_pointer* pointer) {
+  struct wl_proxy* id;
+
+  id = wl_proxy_marshal_constructor(
+      (struct wl_proxy*)zwp_relative_pointer_manager_v1,
+      ZWP_RELATIVE_POINTER_MANAGER_V1_GET_RELATIVE_POINTER,
+      &zwp_relative_pointer_v1_interface, NULL, pointer);
+
+  return (struct zwp_relative_pointer_v1*)id;
+}
+
+/**
+ * @ingroup iface_zwp_relative_pointer_v1
+ * @struct zwp_relative_pointer_v1_listener
+ */
+struct zwp_relative_pointer_v1_listener {
+  /**
+   * relative pointer motion
+   *
+   * Relative x/y pointer motion from the pointer of the seat
+   * associated with this object.
+   *
+   * A relative motion is in the same dimension as regular wl_pointer
+   * motion events, except they do not represent an absolute
+   * position. For example, moving a pointer from (x, y) to (x', y')
+   * would have the equivalent relative motion (x' - x, y' - y). If a
+   * pointer motion caused the absolute pointer position to be
+   * clipped by for example the edge of the monitor, the relative
+   * motion is unaffected by the clipping and will represent the
+   * unclipped motion.
+   *
+   * This event also contains non-accelerated motion deltas. The
+   * non-accelerated delta is, when applicable, the regular pointer
+   * motion delta as it was before having applied motion acceleration
+   * and other transformations such as normalization.
+   *
+   * Note that the non-accelerated delta does not represent 'raw'
+   * events as they were read from some device. Pointer motion
+   * acceleration is device- and configuration-specific and
+   * non-accelerated deltas and accelerated deltas may have the same
+   * value on some devices.
+   *
+   * Relative motions are not coupled to wl_pointer.motion events,
+   * and can be sent in combination with such events, but also
+   * independently. There may also be scenarios where
+   * wl_pointer.motion is sent, but there is no relative motion. The
+   * order of an absolute and relative motion event originating from
+   * the same physical motion is not guaranteed.
+   *
+   * If the client needs button events or focus state, it can receive
+   * them from a wl_pointer object of the same seat that the
+   * wp_relative_pointer object is associated with.
+   * @param utime_hi high 32 bits of a 64 bit timestamp with microsecond
+   * granularity
+   * @param utime_lo low 32 bits of a 64 bit timestamp with microsecond
+   * granularity
+   * @param dx the x component of the motion vector
+   * @param dy the y component of the motion vector
+   * @param dx_unaccel the x component of the unaccelerated motion vector
+   * @param dy_unaccel the y component of the unaccelerated motion vector
+   */
+  void (*relative_motion)(
+      void* data, struct zwp_relative_pointer_v1* zwp_relative_pointer_v1,
+      uint32_t utime_hi, uint32_t utime_lo, wl_fixed_t dx, wl_fixed_t dy,
+      wl_fixed_t dx_unaccel, wl_fixed_t dy_unaccel);
+};
+
+/**
+ * @ingroup iface_zwp_relative_pointer_v1
+ */
+static inline int zwp_relative_pointer_v1_add_listener(
+    struct zwp_relative_pointer_v1* zwp_relative_pointer_v1,
+    const struct zwp_relative_pointer_v1_listener* listener, void* data) {
+  return wl_proxy_add_listener((struct wl_proxy*)zwp_relative_pointer_v1,
+                               (void (**)(void))listener, data);
+}
+
+#define ZWP_RELATIVE_POINTER_V1_DESTROY 0
+
+/**
+ * @ingroup iface_zwp_relative_pointer_v1
+ */
+#define ZWP_RELATIVE_POINTER_V1_RELATIVE_MOTION_SINCE_VERSION 1
+
+/**
+ * @ingroup iface_zwp_relative_pointer_v1
+ */
+#define ZWP_RELATIVE_POINTER_V1_DESTROY_SINCE_VERSION 1
+
+/** @ingroup iface_zwp_relative_pointer_v1 */
+static inline void zwp_relative_pointer_v1_set_user_data(
+    struct zwp_relative_pointer_v1* zwp_relative_pointer_v1, void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)zwp_relative_pointer_v1, user_data);
+}
+
+/** @ingroup iface_zwp_relative_pointer_v1 */
+static inline void* zwp_relative_pointer_v1_get_user_data(
+    struct zwp_relative_pointer_v1* zwp_relative_pointer_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)zwp_relative_pointer_v1);
+}
+
+static inline uint32_t zwp_relative_pointer_v1_get_version(
+    struct zwp_relative_pointer_v1* zwp_relative_pointer_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)zwp_relative_pointer_v1);
+}
+
+/**
+ * @ingroup iface_zwp_relative_pointer_v1
+ */
+static inline void zwp_relative_pointer_v1_destroy(
+    struct zwp_relative_pointer_v1* zwp_relative_pointer_v1) {
+  wl_proxy_marshal((struct wl_proxy*)zwp_relative_pointer_v1,
+                   ZWP_RELATIVE_POINTER_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)zwp_relative_pointer_v1);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/widget/gtk/wayland/relative-pointer-unstable-v1-protocol.c b/widget/gtk/wayland/relative-pointer-unstable-v1-protocol.c
new file mode 100644
index 0000000000..3534686a3d
--- /dev/null
+++ b/widget/gtk/wayland/relative-pointer-unstable-v1-protocol.c
@@ -0,0 +1,69 @@
+/* Generated by wayland-scanner 1.18.0 */
+
+/*
+ * Copyright © 2014      Jonas Ådahl
+ * Copyright © 2015      Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include "wayland-util.h"
+
+#pragma GCC visibility push(default)
+extern const struct wl_interface wl_pointer_interface;
+extern const struct wl_interface zwp_relative_pointer_v1_interface;
+#pragma GCC visibility pop
+
+static const struct wl_interface* relative_pointer_unstable_v1_types[] = {
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    &zwp_relative_pointer_v1_interface,
+    &wl_pointer_interface,
+};
+
+static const struct wl_message zwp_relative_pointer_manager_v1_requests[] = {
+    {"destroy", "", relative_pointer_unstable_v1_types + 0},
+    {"get_relative_pointer", "no", relative_pointer_unstable_v1_types + 6},
+};
+
+WL_EXPORT const struct wl_interface zwp_relative_pointer_manager_v1_interface =
+    {
+        "zwp_relative_pointer_manager_v1",        1, 2,
+        zwp_relative_pointer_manager_v1_requests, 0, NULL,
+};
+
+static const struct wl_message zwp_relative_pointer_v1_requests[] = {
+    {"destroy", "", relative_pointer_unstable_v1_types + 0},
+};
+
+static const struct wl_message zwp_relative_pointer_v1_events[] = {
+    {"relative_motion", "uuffff", relative_pointer_unstable_v1_types + 0},
+};
+
+WL_EXPORT const struct wl_interface zwp_relative_pointer_v1_interface = {
+    "zwp_relative_pointer_v1",        1, 1,
+    zwp_relative_pointer_v1_requests, 1, zwp_relative_pointer_v1_events,
+};
diff --git a/widget/gtk/wayland/viewporter-client-protocol.h b/widget/gtk/wayland/viewporter-client-protocol.h
new file mode 100644
index 0000000000..4c6c5bd910
--- /dev/null
+++ b/widget/gtk/wayland/viewporter-client-protocol.h
@@ -0,0 +1,392 @@
+/* Generated by wayland-scanner 1.18.0 */
+
+#ifndef VIEWPORTER_CLIENT_PROTOCOL_H
+#define VIEWPORTER_CLIENT_PROTOCOL_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include "wayland-client.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @page page_viewporter The viewporter protocol
+ * @section page_ifaces_viewporter Interfaces
+ * - @subpage page_iface_wp_viewporter - surface cropping and scaling
+ * - @subpage page_iface_wp_viewport - crop and scale interface to a wl_surface
+ * @section page_copyright_viewporter Copyright
+ * <pre>
+ *
+ * Copyright © 2013-2016 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ * </pre>
+ */
+struct wl_surface;
+struct wp_viewport;
+struct wp_viewporter;
+
+/**
+ * @page page_iface_wp_viewporter wp_viewporter
+ * @section page_iface_wp_viewporter_desc Description
+ *
+ * The global interface exposing surface cropping and scaling
+ * capabilities is used to instantiate an interface extension for a
+ * wl_surface object. This extended interface will then allow
+ * cropping and scaling the surface contents, effectively
+ * disconnecting the direct relationship between the buffer and the
+ * surface size.
+ * @section page_iface_wp_viewporter_api API
+ * See @ref iface_wp_viewporter.
+ */
+/**
+ * @defgroup iface_wp_viewporter The wp_viewporter interface
+ *
+ * The global interface exposing surface cropping and scaling
+ * capabilities is used to instantiate an interface extension for a
+ * wl_surface object. This extended interface will then allow
+ * cropping and scaling the surface contents, effectively
+ * disconnecting the direct relationship between the buffer and the
+ * surface size.
+ */
+extern const struct wl_interface wp_viewporter_interface;
+/**
+ * @page page_iface_wp_viewport wp_viewport
+ * @section page_iface_wp_viewport_desc Description
+ *
+ * An additional interface to a wl_surface object, which allows the
+ * client to specify the cropping and scaling of the surface
+ * contents.
+ *
+ * This interface works with two concepts: the source rectangle (src_x,
+ * src_y, src_width, src_height), and the destination size (dst_width,
+ * dst_height). The contents of the source rectangle are scaled to the
+ * destination size, and content outside the source rectangle is ignored.
+ * This state is double-buffered, and is applied on the next
+ * wl_surface.commit.
+ *
+ * The two parts of crop and scale state are independent: the source
+ * rectangle, and the destination size. Initially both are unset, that
+ * is, no scaling is applied. The whole of the current wl_buffer is
+ * used as the source, and the surface size is as defined in
+ * wl_surface.attach.
+ *
+ * If the destination size is set, it causes the surface size to become
+ * dst_width, dst_height. The source (rectangle) is scaled to exactly
+ * this size. This overrides whatever the attached wl_buffer size is,
+ * unless the wl_buffer is NULL. If the wl_buffer is NULL, the surface
+ * has no content and therefore no size. Otherwise, the size is always
+ * at least 1x1 in surface local coordinates.
+ *
+ * If the source rectangle is set, it defines what area of the wl_buffer is
+ * taken as the source. If the source rectangle is set and the destination
+ * size is not set, then src_width and src_height must be integers, and the
+ * surface size becomes the source rectangle size. This results in cropping
+ * without scaling. If src_width or src_height are not integers and
+ * destination size is not set, the bad_size protocol error is raised when
+ * the surface state is applied.
+ *
+ * The coordinate transformations from buffer pixel coordinates up to
+ * the surface-local coordinates happen in the following order:
+ * 1. buffer_transform (wl_surface.set_buffer_transform)
+ * 2. buffer_scale (wl_surface.set_buffer_scale)
+ * 3. crop and scale (wp_viewport.set*)
+ * This means, that the source rectangle coordinates of crop and scale
+ * are given in the coordinates after the buffer transform and scale,
+ * i.e. in the coordinates that would be the surface-local coordinates
+ * if the crop and scale was not applied.
+ *
+ * If src_x or src_y are negative, the bad_value protocol error is raised.
+ * Otherwise, if the source rectangle is partially or completely outside of
+ * the non-NULL wl_buffer, then the out_of_buffer protocol error is raised
+ * when the surface state is applied. A NULL wl_buffer does not raise the
+ * out_of_buffer error.
+ *
+ * The x, y arguments of wl_surface.attach are applied as normal to
+ * the surface. They indicate how many pixels to remove from the
+ * surface size from the left and the top. In other words, they are
+ * still in the surface-local coordinate system, just like dst_width
+ * and dst_height are.
+ *
+ * If the wl_surface associated with the wp_viewport is destroyed,
+ * all wp_viewport requests except 'destroy' raise the protocol error
+ * no_surface.
+ *
+ * If the wp_viewport object is destroyed, the crop and scale
+ * state is removed from the wl_surface. The change will be applied
+ * on the next wl_surface.commit.
+ * @section page_iface_wp_viewport_api API
+ * See @ref iface_wp_viewport.
+ */
+/**
+ * @defgroup iface_wp_viewport The wp_viewport interface
+ *
+ * An additional interface to a wl_surface object, which allows the
+ * client to specify the cropping and scaling of the surface
+ * contents.
+ *
+ * This interface works with two concepts: the source rectangle (src_x,
+ * src_y, src_width, src_height), and the destination size (dst_width,
+ * dst_height). The contents of the source rectangle are scaled to the
+ * destination size, and content outside the source rectangle is ignored.
+ * This state is double-buffered, and is applied on the next
+ * wl_surface.commit.
+ *
+ * The two parts of crop and scale state are independent: the source
+ * rectangle, and the destination size. Initially both are unset, that
+ * is, no scaling is applied. The whole of the current wl_buffer is
+ * used as the source, and the surface size is as defined in
+ * wl_surface.attach.
+ *
+ * If the destination size is set, it causes the surface size to become
+ * dst_width, dst_height. The source (rectangle) is scaled to exactly
+ * this size. This overrides whatever the attached wl_buffer size is,
+ * unless the wl_buffer is NULL. If the wl_buffer is NULL, the surface
+ * has no content and therefore no size. Otherwise, the size is always
+ * at least 1x1 in surface local coordinates.
+ *
+ * If the source rectangle is set, it defines what area of the wl_buffer is
+ * taken as the source. If the source rectangle is set and the destination
+ * size is not set, then src_width and src_height must be integers, and the
+ * surface size becomes the source rectangle size. This results in cropping
+ * without scaling. If src_width or src_height are not integers and
+ * destination size is not set, the bad_size protocol error is raised when
+ * the surface state is applied.
+ *
+ * The coordinate transformations from buffer pixel coordinates up to
+ * the surface-local coordinates happen in the following order:
+ * 1. buffer_transform (wl_surface.set_buffer_transform)
+ * 2. buffer_scale (wl_surface.set_buffer_scale)
+ * 3. crop and scale (wp_viewport.set*)
+ * This means, that the source rectangle coordinates of crop and scale
+ * are given in the coordinates after the buffer transform and scale,
+ * i.e. in the coordinates that would be the surface-local coordinates
+ * if the crop and scale was not applied.
+ *
+ * If src_x or src_y are negative, the bad_value protocol error is raised.
+ * Otherwise, if the source rectangle is partially or completely outside of
+ * the non-NULL wl_buffer, then the out_of_buffer protocol error is raised
+ * when the surface state is applied. A NULL wl_buffer does not raise the
+ * out_of_buffer error.
+ *
+ * The x, y arguments of wl_surface.attach are applied as normal to
+ * the surface. They indicate how many pixels to remove from the
+ * surface size from the left and the top. In other words, they are
+ * still in the surface-local coordinate system, just like dst_width
+ * and dst_height are.
+ *
+ * If the wl_surface associated with the wp_viewport is destroyed,
+ * all wp_viewport requests except 'destroy' raise the protocol error
+ * no_surface.
+ *
+ * If the wp_viewport object is destroyed, the crop and scale
+ * state is removed from the wl_surface. The change will be applied
+ * on the next wl_surface.commit.
+ */
+extern const struct wl_interface wp_viewport_interface;
+
+#ifndef WP_VIEWPORTER_ERROR_ENUM
+#  define WP_VIEWPORTER_ERROR_ENUM
+enum wp_viewporter_error {
+  /**
+   * the surface already has a viewport object associated
+   */
+  WP_VIEWPORTER_ERROR_VIEWPORT_EXISTS = 0,
+};
+#endif /* WP_VIEWPORTER_ERROR_ENUM */
+
+#define WP_VIEWPORTER_DESTROY 0
+#define WP_VIEWPORTER_GET_VIEWPORT 1
+
+/**
+ * @ingroup iface_wp_viewporter
+ */
+#define WP_VIEWPORTER_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_wp_viewporter
+ */
+#define WP_VIEWPORTER_GET_VIEWPORT_SINCE_VERSION 1
+
+/** @ingroup iface_wp_viewporter */
+static inline void wp_viewporter_set_user_data(
+    struct wp_viewporter* wp_viewporter, void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)wp_viewporter, user_data);
+}
+
+/** @ingroup iface_wp_viewporter */
+static inline void* wp_viewporter_get_user_data(
+    struct wp_viewporter* wp_viewporter) {
+  return wl_proxy_get_user_data((struct wl_proxy*)wp_viewporter);
+}
+
+static inline uint32_t wp_viewporter_get_version(
+    struct wp_viewporter* wp_viewporter) {
+  return wl_proxy_get_version((struct wl_proxy*)wp_viewporter);
+}
+
+/**
+ * @ingroup iface_wp_viewporter
+ *
+ * Informs the server that the client will not be using this
+ * protocol object anymore. This does not affect any other objects,
+ * wp_viewport objects included.
+ */
+static inline void wp_viewporter_destroy(struct wp_viewporter* wp_viewporter) {
+  wl_proxy_marshal((struct wl_proxy*)wp_viewporter, WP_VIEWPORTER_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)wp_viewporter);
+}
+
+/**
+ * @ingroup iface_wp_viewporter
+ *
+ * Instantiate an interface extension for the given wl_surface to
+ * crop and scale its content. If the given wl_surface already has
+ * a wp_viewport object associated, the viewport_exists
+ * protocol error is raised.
+ */
+static inline struct wp_viewport* wp_viewporter_get_viewport(
+    struct wp_viewporter* wp_viewporter, struct wl_surface* surface) {
+  struct wl_proxy* id;
+
+  id = wl_proxy_marshal_constructor((struct wl_proxy*)wp_viewporter,
+                                    WP_VIEWPORTER_GET_VIEWPORT,
+                                    &wp_viewport_interface, NULL, surface);
+
+  return (struct wp_viewport*)id;
+}
+
+#ifndef WP_VIEWPORT_ERROR_ENUM
+#  define WP_VIEWPORT_ERROR_ENUM
+enum wp_viewport_error {
+  /**
+   * negative or zero values in width or height
+   */
+  WP_VIEWPORT_ERROR_BAD_VALUE = 0,
+  /**
+   * destination size is not integer
+   */
+  WP_VIEWPORT_ERROR_BAD_SIZE = 1,
+  /**
+   * source rectangle extends outside of the content area
+   */
+  WP_VIEWPORT_ERROR_OUT_OF_BUFFER = 2,
+  /**
+   * the wl_surface was destroyed
+   */
+  WP_VIEWPORT_ERROR_NO_SURFACE = 3,
+};
+#endif /* WP_VIEWPORT_ERROR_ENUM */
+
+#define WP_VIEWPORT_DESTROY 0
+#define WP_VIEWPORT_SET_SOURCE 1
+#define WP_VIEWPORT_SET_DESTINATION 2
+
+/**
+ * @ingroup iface_wp_viewport
+ */
+#define WP_VIEWPORT_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_wp_viewport
+ */
+#define WP_VIEWPORT_SET_SOURCE_SINCE_VERSION 1
+/**
+ * @ingroup iface_wp_viewport
+ */
+#define WP_VIEWPORT_SET_DESTINATION_SINCE_VERSION 1
+
+/** @ingroup iface_wp_viewport */
+static inline void wp_viewport_set_user_data(struct wp_viewport* wp_viewport,
+                                             void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)wp_viewport, user_data);
+}
+
+/** @ingroup iface_wp_viewport */
+static inline void* wp_viewport_get_user_data(struct wp_viewport* wp_viewport) {
+  return wl_proxy_get_user_data((struct wl_proxy*)wp_viewport);
+}
+
+static inline uint32_t wp_viewport_get_version(
+    struct wp_viewport* wp_viewport) {
+  return wl_proxy_get_version((struct wl_proxy*)wp_viewport);
+}
+
+/**
+ * @ingroup iface_wp_viewport
+ *
+ * The associated wl_surface's crop and scale state is removed.
+ * The change is applied on the next wl_surface.commit.
+ */
+static inline void wp_viewport_destroy(struct wp_viewport* wp_viewport) {
+  wl_proxy_marshal((struct wl_proxy*)wp_viewport, WP_VIEWPORT_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)wp_viewport);
+}
+
+/**
+ * @ingroup iface_wp_viewport
+ *
+ * Set the source rectangle of the associated wl_surface. See
+ * wp_viewport for the description, and relation to the wl_buffer
+ * size.
+ *
+ * If all of x, y, width and height are -1.0, the source rectangle is
+ * unset instead. Any other set of values where width or height are zero
+ * or negative, or x or y are negative, raise the bad_value protocol
+ * error.
+ *
+ * The crop and scale state is double-buffered state, and will be
+ * applied on the next wl_surface.commit.
+ */
+static inline void wp_viewport_set_source(struct wp_viewport* wp_viewport,
+                                          wl_fixed_t x, wl_fixed_t y,
+                                          wl_fixed_t width, wl_fixed_t height) {
+  wl_proxy_marshal((struct wl_proxy*)wp_viewport, WP_VIEWPORT_SET_SOURCE, x, y,
+                   width, height);
+}
+
+/**
+ * @ingroup iface_wp_viewport
+ *
+ * Set the destination size of the associated wl_surface. See
+ * wp_viewport for the description, and relation to the wl_buffer
+ * size.
+ *
+ * If width is -1 and height is -1, the destination size is unset
+ * instead. Any other pair of values for width and height that
+ * contains zero or negative values raises the bad_value protocol
+ * error.
+ *
+ * The crop and scale state is double-buffered state, and will be
+ * applied on the next wl_surface.commit.
+ */
+static inline void wp_viewport_set_destination(struct wp_viewport* wp_viewport,
+                                               int32_t width, int32_t height) {
+  wl_proxy_marshal((struct wl_proxy*)wp_viewport, WP_VIEWPORT_SET_DESTINATION,
+                   width, height);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/widget/gtk/wayland/viewporter-protocol.c b/widget/gtk/wayland/viewporter-protocol.c
new file mode 100644
index 0000000000..06b7901426
--- /dev/null
+++ b/widget/gtk/wayland/viewporter-protocol.c
@@ -0,0 +1,56 @@
+/* Generated by wayland-scanner 1.18.0 */
+
+/*
+ * Copyright © 2013-2016 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include "wayland-util.h"
+
+#pragma GCC visibility push(default)
+extern const struct wl_interface wl_surface_interface;
+extern const struct wl_interface wp_viewport_interface;
+#pragma GCC visibility pop
+
+static const struct wl_interface* viewporter_types[] = {
+    NULL, NULL, NULL, NULL, &wp_viewport_interface, &wl_surface_interface,
+};
+
+static const struct wl_message wp_viewporter_requests[] = {
+    {"destroy", "", viewporter_types + 0},
+    {"get_viewport", "no", viewporter_types + 4},
+};
+
+const struct wl_interface wp_viewporter_interface = {
+    "wp_viewporter", 1, 2, wp_viewporter_requests, 0, NULL,
+};
+
+static const struct wl_message wp_viewport_requests[] = {
+    {"destroy", "", viewporter_types + 0},
+    {"set_source", "ffff", viewporter_types + 0},
+    {"set_destination", "ii", viewporter_types + 0},
+};
+
+const struct wl_interface wp_viewport_interface = {
+    "wp_viewport", 1, 3, wp_viewport_requests, 0, NULL,
+};
diff --git a/widget/gtk/wayland/xdg-activation-v1-client-protocol.h b/widget/gtk/wayland/xdg-activation-v1-client-protocol.h
new file mode 100644
index 0000000000..9bebcb6ec2
--- /dev/null
+++ b/widget/gtk/wayland/xdg-activation-v1-client-protocol.h
@@ -0,0 +1,409 @@
+/* Generated by wayland-scanner 1.19.0 */
+
+#ifndef XDG_ACTIVATION_V1_CLIENT_PROTOCOL_H
+#define XDG_ACTIVATION_V1_CLIENT_PROTOCOL_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include "wayland-client.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @page page_xdg_activation_v1 The xdg_activation_v1 protocol
+ * Protocol for requesting activation of surfaces
+ *
+ * @section page_desc_xdg_activation_v1 Description
+ *
+ * The way for a client to pass focus to another toplevel is as follows.
+ *
+ * The client that intends to activate another toplevel uses the
+ * xdg_activation_v1.get_activation_token request to get an activation token.
+ * This token is then forwarded to the client, which is supposed to activate
+ * one of its surfaces, through a separate band of communication.
+ *
+ * One established way of doing this is through the XDG_ACTIVATION_TOKEN
+ * environment variable of a newly launched child process. The child process
+ * should unset the environment variable again right after reading it out in
+ * order to avoid propagating it to other child processes.
+ *
+ * Another established way exists for Applications implementing the D-Bus
+ * interface org.freedesktop.Application, which should get their token under
+ * XDG_ACTIVATION_TOKEN on their platform_data.
+ *
+ * In general activation tokens may be transferred across clients through
+ * means not described in this protocol.
+ *
+ * The client to be activated will then pass the token
+ * it received to the xdg_activation_v1.activate request. The compositor can
+ * then use this token to decide how to react to the activation request.
+ *
+ * The token the activating client gets may be ineffective either already at
+ * the time it receives it, for example if it was not focused, for focus
+ * stealing prevention. The activating client will have no way to discover
+ * the validity of the token, and may still forward it to the to be activated
+ * client.
+ *
+ * The created activation token may optionally get information attached to it
+ * that can be used by the compositor to identify the application that we
+ * intend to activate. This can for example be used to display a visual hint
+ * about what application is being started.
+ *
+ * Warning! The protocol described in this file is currently in the testing
+ * phase. Backward compatible changes may be added together with the
+ * corresponding interface version bump. Backward incompatible changes can
+ * only be done by creating a new major version of the extension.
+ *
+ * @section page_ifaces_xdg_activation_v1 Interfaces
+ * - @subpage page_iface_xdg_activation_v1 - interface for activating surfaces
+ * - @subpage page_iface_xdg_activation_token_v1 - an exported activation handle
+ * @section page_copyright_xdg_activation_v1 Copyright
+ * <pre>
+ *
+ * Copyright © 2020 Aleix Pol Gonzalez <aleixpol@kde.org>
+ * Copyright © 2020 Carlos Garnacho <carlosg@gnome.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ * </pre>
+ */
+struct wl_seat;
+struct wl_surface;
+struct xdg_activation_token_v1;
+struct xdg_activation_v1;
+
+#ifndef XDG_ACTIVATION_V1_INTERFACE
+#  define XDG_ACTIVATION_V1_INTERFACE
+/**
+ * @page page_iface_xdg_activation_v1 xdg_activation_v1
+ * @section page_iface_xdg_activation_v1_desc Description
+ *
+ * A global interface used for informing the compositor about applications
+ * being activated or started, or for applications to request to be
+ * activated.
+ * @section page_iface_xdg_activation_v1_api API
+ * See @ref iface_xdg_activation_v1.
+ */
+/**
+ * @defgroup iface_xdg_activation_v1 The xdg_activation_v1 interface
+ *
+ * A global interface used for informing the compositor about applications
+ * being activated or started, or for applications to request to be
+ * activated.
+ */
+extern const struct wl_interface xdg_activation_v1_interface;
+#endif
+#ifndef XDG_ACTIVATION_TOKEN_V1_INTERFACE
+#  define XDG_ACTIVATION_TOKEN_V1_INTERFACE
+/**
+ * @page page_iface_xdg_activation_token_v1 xdg_activation_token_v1
+ * @section page_iface_xdg_activation_token_v1_desc Description
+ *
+ * An object for setting up a token and receiving a token handle that can
+ * be passed as an activation token to another client.
+ *
+ * The object is created using the xdg_activation_v1.get_activation_token
+ * request. This object should then be populated with the app_id, surface
+ * and serial information and committed. The compositor shall then issue a
+ * done event with the token. In case the request's parameters are invalid,
+ * the compositor will provide an invalid token.
+ * @section page_iface_xdg_activation_token_v1_api API
+ * See @ref iface_xdg_activation_token_v1.
+ */
+/**
+ * @defgroup iface_xdg_activation_token_v1 The xdg_activation_token_v1 interface
+ *
+ * An object for setting up a token and receiving a token handle that can
+ * be passed as an activation token to another client.
+ *
+ * The object is created using the xdg_activation_v1.get_activation_token
+ * request. This object should then be populated with the app_id, surface
+ * and serial information and committed. The compositor shall then issue a
+ * done event with the token. In case the request's parameters are invalid,
+ * the compositor will provide an invalid token.
+ */
+extern const struct wl_interface xdg_activation_token_v1_interface;
+#endif
+
+#define XDG_ACTIVATION_V1_DESTROY 0
+#define XDG_ACTIVATION_V1_GET_ACTIVATION_TOKEN 1
+#define XDG_ACTIVATION_V1_ACTIVATE 2
+
+/**
+ * @ingroup iface_xdg_activation_v1
+ */
+#define XDG_ACTIVATION_V1_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_xdg_activation_v1
+ */
+#define XDG_ACTIVATION_V1_GET_ACTIVATION_TOKEN_SINCE_VERSION 1
+/**
+ * @ingroup iface_xdg_activation_v1
+ */
+#define XDG_ACTIVATION_V1_ACTIVATE_SINCE_VERSION 1
+
+/** @ingroup iface_xdg_activation_v1 */
+static inline void xdg_activation_v1_set_user_data(
+    struct xdg_activation_v1* xdg_activation_v1, void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)xdg_activation_v1, user_data);
+}
+
+/** @ingroup iface_xdg_activation_v1 */
+static inline void* xdg_activation_v1_get_user_data(
+    struct xdg_activation_v1* xdg_activation_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)xdg_activation_v1);
+}
+
+static inline uint32_t xdg_activation_v1_get_version(
+    struct xdg_activation_v1* xdg_activation_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)xdg_activation_v1);
+}
+
+/**
+ * @ingroup iface_xdg_activation_v1
+ *
+ * Notify the compositor that the xdg_activation object will no longer be
+ * used.
+ *
+ * The child objects created via this interface are unaffected and should
+ * be destroyed separately.
+ */
+static inline void xdg_activation_v1_destroy(
+    struct xdg_activation_v1* xdg_activation_v1) {
+  wl_proxy_marshal((struct wl_proxy*)xdg_activation_v1,
+                   XDG_ACTIVATION_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)xdg_activation_v1);
+}
+
+/**
+ * @ingroup iface_xdg_activation_v1
+ *
+ * Creates an xdg_activation_token_v1 object that will provide
+ * the initiating client with a unique token for this activation. This
+ * token should be offered to the clients to be activated.
+ */
+static inline struct xdg_activation_token_v1*
+xdg_activation_v1_get_activation_token(
+    struct xdg_activation_v1* xdg_activation_v1) {
+  struct wl_proxy* id;
+
+  id = wl_proxy_marshal_constructor((struct wl_proxy*)xdg_activation_v1,
+                                    XDG_ACTIVATION_V1_GET_ACTIVATION_TOKEN,
+                                    &xdg_activation_token_v1_interface, NULL);
+
+  return (struct xdg_activation_token_v1*)id;
+}
+
+/**
+ * @ingroup iface_xdg_activation_v1
+ *
+ * Requests surface activation. It's up to the compositor to display
+ * this information as desired, for example by placing the surface above
+ * the rest.
+ *
+ * The compositor may know who requested this by checking the activation
+ * token and might decide not to follow through with the activation if it's
+ * considered unwanted.
+ *
+ * Compositors can ignore unknown activation tokens when an invalid
+ * token is passed.
+ */
+static inline void xdg_activation_v1_activate(
+    struct xdg_activation_v1* xdg_activation_v1, const char* token,
+    struct wl_surface* surface) {
+  wl_proxy_marshal((struct wl_proxy*)xdg_activation_v1,
+                   XDG_ACTIVATION_V1_ACTIVATE, token, surface);
+}
+
+#ifndef XDG_ACTIVATION_TOKEN_V1_ERROR_ENUM
+#  define XDG_ACTIVATION_TOKEN_V1_ERROR_ENUM
+enum xdg_activation_token_v1_error {
+  /**
+   * The token has already been used previously
+   */
+  XDG_ACTIVATION_TOKEN_V1_ERROR_ALREADY_USED = 0,
+};
+#endif /* XDG_ACTIVATION_TOKEN_V1_ERROR_ENUM */
+
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ * @struct xdg_activation_token_v1_listener
+ */
+struct xdg_activation_token_v1_listener {
+  /**
+   * the exported activation token
+   *
+   * The 'done' event contains the unique token of this activation
+   * request and notifies that the provider is done.
+   * @param token the exported activation token
+   */
+  void (*done)(void* data,
+               struct xdg_activation_token_v1* xdg_activation_token_v1,
+               const char* token);
+};
+
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ */
+static inline int xdg_activation_token_v1_add_listener(
+    struct xdg_activation_token_v1* xdg_activation_token_v1,
+    const struct xdg_activation_token_v1_listener* listener, void* data) {
+  return wl_proxy_add_listener((struct wl_proxy*)xdg_activation_token_v1,
+                               (void (**)(void))listener, data);
+}
+
+#define XDG_ACTIVATION_TOKEN_V1_SET_SERIAL 0
+#define XDG_ACTIVATION_TOKEN_V1_SET_APP_ID 1
+#define XDG_ACTIVATION_TOKEN_V1_SET_SURFACE 2
+#define XDG_ACTIVATION_TOKEN_V1_COMMIT 3
+#define XDG_ACTIVATION_TOKEN_V1_DESTROY 4
+
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ */
+#define XDG_ACTIVATION_TOKEN_V1_DONE_SINCE_VERSION 1
+
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ */
+#define XDG_ACTIVATION_TOKEN_V1_SET_SERIAL_SINCE_VERSION 1
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ */
+#define XDG_ACTIVATION_TOKEN_V1_SET_APP_ID_SINCE_VERSION 1
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ */
+#define XDG_ACTIVATION_TOKEN_V1_SET_SURFACE_SINCE_VERSION 1
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ */
+#define XDG_ACTIVATION_TOKEN_V1_COMMIT_SINCE_VERSION 1
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ */
+#define XDG_ACTIVATION_TOKEN_V1_DESTROY_SINCE_VERSION 1
+
+/** @ingroup iface_xdg_activation_token_v1 */
+static inline void xdg_activation_token_v1_set_user_data(
+    struct xdg_activation_token_v1* xdg_activation_token_v1, void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)xdg_activation_token_v1, user_data);
+}
+
+/** @ingroup iface_xdg_activation_token_v1 */
+static inline void* xdg_activation_token_v1_get_user_data(
+    struct xdg_activation_token_v1* xdg_activation_token_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)xdg_activation_token_v1);
+}
+
+static inline uint32_t xdg_activation_token_v1_get_version(
+    struct xdg_activation_token_v1* xdg_activation_token_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)xdg_activation_token_v1);
+}
+
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ *
+ * Provides information about the seat and serial event that requested the
+ * token.
+ *
+ * The serial can come from an input or focus event. For instance, if a
+ * click triggers the launch of a third-party client, the launcher client
+ * should send a set_serial request with the serial and seat from the
+ * wl_pointer.button event.
+ *
+ * Some compositors might refuse to activate toplevels when the token
+ * doesn't have a valid and recent enough event serial.
+ *
+ * Must be sent before commit. This information is optional.
+ */
+static inline void xdg_activation_token_v1_set_serial(
+    struct xdg_activation_token_v1* xdg_activation_token_v1, uint32_t serial,
+    struct wl_seat* seat) {
+  wl_proxy_marshal((struct wl_proxy*)xdg_activation_token_v1,
+                   XDG_ACTIVATION_TOKEN_V1_SET_SERIAL, serial, seat);
+}
+
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ *
+ * The requesting client can specify an app_id to associate the token
+ * being created with it.
+ *
+ * Must be sent before commit. This information is optional.
+ */
+static inline void xdg_activation_token_v1_set_app_id(
+    struct xdg_activation_token_v1* xdg_activation_token_v1,
+    const char* app_id) {
+  wl_proxy_marshal((struct wl_proxy*)xdg_activation_token_v1,
+                   XDG_ACTIVATION_TOKEN_V1_SET_APP_ID, app_id);
+}
+
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ *
+ * This request sets the surface requesting the activation. Note, this is
+ * different from the surface that will be activated.
+ *
+ * Some compositors might refuse to activate toplevels when the token
+ * doesn't have a requesting surface.
+ *
+ * Must be sent before commit. This information is optional.
+ */
+static inline void xdg_activation_token_v1_set_surface(
+    struct xdg_activation_token_v1* xdg_activation_token_v1,
+    struct wl_surface* surface) {
+  wl_proxy_marshal((struct wl_proxy*)xdg_activation_token_v1,
+                   XDG_ACTIVATION_TOKEN_V1_SET_SURFACE, surface);
+}
+
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ *
+ * Requests an activation token based on the different parameters that
+ * have been offered through set_serial, set_surface and set_app_id.
+ */
+static inline void xdg_activation_token_v1_commit(
+    struct xdg_activation_token_v1* xdg_activation_token_v1) {
+  wl_proxy_marshal((struct wl_proxy*)xdg_activation_token_v1,
+                   XDG_ACTIVATION_TOKEN_V1_COMMIT);
+}
+
+/**
+ * @ingroup iface_xdg_activation_token_v1
+ *
+ * Notify the compositor that the xdg_activation_token_v1 object will no
+ * longer be used.
+ */
+static inline void xdg_activation_token_v1_destroy(
+    struct xdg_activation_token_v1* xdg_activation_token_v1) {
+  wl_proxy_marshal((struct wl_proxy*)xdg_activation_token_v1,
+                   XDG_ACTIVATION_TOKEN_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)xdg_activation_token_v1);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/widget/gtk/wayland/xdg-activation-v1-protocol.c b/widget/gtk/wayland/xdg-activation-v1-protocol.c
new file mode 100644
index 0000000000..1fad6dbf97
--- /dev/null
+++ b/widget/gtk/wayland/xdg-activation-v1-protocol.c
@@ -0,0 +1,82 @@
+/* Generated by wayland-scanner 1.19.0 */
+
+/*
+ * Copyright © 2020 Aleix Pol Gonzalez <aleixpol@kde.org>
+ * Copyright © 2020 Carlos Garnacho <carlosg@gnome.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include "wayland-util.h"
+
+#ifndef __has_attribute
+#  define __has_attribute(x) 0 /* Compatibility with non-clang compilers. */
+#endif
+
+#if (__has_attribute(visibility) || defined(__GNUC__) && __GNUC__ >= 4)
+#  define WL_PRIVATE __attribute__((visibility("hidden")))
+#else
+#  define WL_PRIVATE
+#endif
+
+#pragma GCC visibility push(default)
+extern const struct wl_interface wl_seat_interface;
+extern const struct wl_interface wl_surface_interface;
+#pragma GCC visibility pop
+extern const struct wl_interface xdg_activation_token_v1_interface;
+
+static const struct wl_interface* xdg_activation_v1_types[] = {
+    NULL,
+    &xdg_activation_token_v1_interface,
+    NULL,
+    &wl_surface_interface,
+    NULL,
+    &wl_seat_interface,
+    &wl_surface_interface,
+};
+
+static const struct wl_message xdg_activation_v1_requests[] = {
+    {"destroy", "", xdg_activation_v1_types + 0},
+    {"get_activation_token", "n", xdg_activation_v1_types + 1},
+    {"activate", "so", xdg_activation_v1_types + 2},
+};
+
+WL_PRIVATE const struct wl_interface xdg_activation_v1_interface = {
+    "xdg_activation_v1", 1, 3, xdg_activation_v1_requests, 0, NULL,
+};
+
+static const struct wl_message xdg_activation_token_v1_requests[] = {
+    {"set_serial", "uo", xdg_activation_v1_types + 4},
+    {"set_app_id", "s", xdg_activation_v1_types + 0},
+    {"set_surface", "o", xdg_activation_v1_types + 6},
+    {"commit", "", xdg_activation_v1_types + 0},
+    {"destroy", "", xdg_activation_v1_types + 0},
+};
+
+static const struct wl_message xdg_activation_token_v1_events[] = {
+    {"done", "s", xdg_activation_v1_types + 0},
+};
+
+WL_PRIVATE const struct wl_interface xdg_activation_token_v1_interface = {
+    "xdg_activation_token_v1",        1, 5,
+    xdg_activation_token_v1_requests, 1, xdg_activation_token_v1_events,
+};
diff --git a/widget/gtk/wayland/xdg-output-unstable-v1-client-protocol.h b/widget/gtk/wayland/xdg-output-unstable-v1-client-protocol.h
new file mode 100644
index 0000000000..432057ccef
--- /dev/null
+++ b/widget/gtk/wayland/xdg-output-unstable-v1-client-protocol.h
@@ -0,0 +1,392 @@
+/* Generated by wayland-scanner 1.18.0 */
+
+#ifndef XDG_OUTPUT_UNSTABLE_V1_CLIENT_PROTOCOL_H
+#define XDG_OUTPUT_UNSTABLE_V1_CLIENT_PROTOCOL_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include "wayland-client.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @page page_xdg_output_unstable_v1 The xdg_output_unstable_v1 protocol
+ * Protocol to describe output regions
+ *
+ * @section page_desc_xdg_output_unstable_v1 Description
+ *
+ * This protocol aims at describing outputs in a way which is more in line
+ * with the concept of an output on desktop oriented systems.
+ *
+ * Some information are more specific to the concept of an output for
+ * a desktop oriented system and may not make sense in other applications,
+ * such as IVI systems for example.
+ *
+ * Typically, the global compositor space on a desktop system is made of
+ * a contiguous or overlapping set of rectangular regions.
+ *
+ * Some of the information provided in this protocol might be identical
+ * to their counterparts already available from wl_output, in which case
+ * the information provided by this protocol should be preferred to their
+ * equivalent in wl_output. The goal is to move the desktop specific
+ * concepts (such as output location within the global compositor space,
+ * the connector name and types, etc.) out of the core wl_output protocol.
+ *
+ * Warning! The protocol described in this file is experimental and
+ * backward incompatible changes may be made. Backward compatible
+ * changes may be added together with the corresponding interface
+ * version bump.
+ * Backward incompatible changes are done by bumping the version
+ * number in the protocol and interface names and resetting the
+ * interface version. Once the protocol is to be declared stable,
+ * the 'z' prefix and the version number in the protocol and
+ * interface names are removed and the interface version number is
+ * reset.
+ *
+ * @section page_ifaces_xdg_output_unstable_v1 Interfaces
+ * - @subpage page_iface_zxdg_output_manager_v1 - manage xdg_output objects
+ * - @subpage page_iface_zxdg_output_v1 - compositor logical output region
+ * @section page_copyright_xdg_output_unstable_v1 Copyright
+ * <pre>
+ *
+ * Copyright © 2017 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ * </pre>
+ */
+struct wl_output;
+struct zxdg_output_manager_v1;
+struct zxdg_output_v1;
+
+/**
+ * @page page_iface_zxdg_output_manager_v1 zxdg_output_manager_v1
+ * @section page_iface_zxdg_output_manager_v1_desc Description
+ *
+ * A global factory interface for xdg_output objects.
+ * @section page_iface_zxdg_output_manager_v1_api API
+ * See @ref iface_zxdg_output_manager_v1.
+ */
+/**
+ * @defgroup iface_zxdg_output_manager_v1 The zxdg_output_manager_v1 interface
+ *
+ * A global factory interface for xdg_output objects.
+ */
+extern const struct wl_interface zxdg_output_manager_v1_interface;
+/**
+ * @page page_iface_zxdg_output_v1 zxdg_output_v1
+ * @section page_iface_zxdg_output_v1_desc Description
+ *
+ * An xdg_output describes part of the compositor geometry.
+ *
+ * This typically corresponds to a monitor that displays part of the
+ * compositor space.
+ *
+ * For objects version 3 onwards, after all xdg_output properties have been
+ * sent (when the object is created and when properties are updated), a
+ * wl_output.done event is sent. This allows changes to the output
+ * properties to be seen as atomic, even if they happen via multiple events.
+ * @section page_iface_zxdg_output_v1_api API
+ * See @ref iface_zxdg_output_v1.
+ */
+/**
+ * @defgroup iface_zxdg_output_v1 The zxdg_output_v1 interface
+ *
+ * An xdg_output describes part of the compositor geometry.
+ *
+ * This typically corresponds to a monitor that displays part of the
+ * compositor space.
+ *
+ * For objects version 3 onwards, after all xdg_output properties have been
+ * sent (when the object is created and when properties are updated), a
+ * wl_output.done event is sent. This allows changes to the output
+ * properties to be seen as atomic, even if they happen via multiple events.
+ */
+extern const struct wl_interface zxdg_output_v1_interface;
+
+#define ZXDG_OUTPUT_MANAGER_V1_DESTROY 0
+#define ZXDG_OUTPUT_MANAGER_V1_GET_XDG_OUTPUT 1
+
+/**
+ * @ingroup iface_zxdg_output_manager_v1
+ */
+#define ZXDG_OUTPUT_MANAGER_V1_DESTROY_SINCE_VERSION 1
+/**
+ * @ingroup iface_zxdg_output_manager_v1
+ */
+#define ZXDG_OUTPUT_MANAGER_V1_GET_XDG_OUTPUT_SINCE_VERSION 1
+
+/** @ingroup iface_zxdg_output_manager_v1 */
+static inline void zxdg_output_manager_v1_set_user_data(
+    struct zxdg_output_manager_v1* zxdg_output_manager_v1, void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)zxdg_output_manager_v1, user_data);
+}
+
+/** @ingroup iface_zxdg_output_manager_v1 */
+static inline void* zxdg_output_manager_v1_get_user_data(
+    struct zxdg_output_manager_v1* zxdg_output_manager_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)zxdg_output_manager_v1);
+}
+
+static inline uint32_t zxdg_output_manager_v1_get_version(
+    struct zxdg_output_manager_v1* zxdg_output_manager_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)zxdg_output_manager_v1);
+}
+
+/**
+ * @ingroup iface_zxdg_output_manager_v1
+ *
+ * Using this request a client can tell the server that it is not
+ * going to use the xdg_output_manager object anymore.
+ *
+ * Any objects already created through this instance are not affected.
+ */
+static inline void zxdg_output_manager_v1_destroy(
+    struct zxdg_output_manager_v1* zxdg_output_manager_v1) {
+  wl_proxy_marshal((struct wl_proxy*)zxdg_output_manager_v1,
+                   ZXDG_OUTPUT_MANAGER_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)zxdg_output_manager_v1);
+}
+
+/**
+ * @ingroup iface_zxdg_output_manager_v1
+ *
+ * This creates a new xdg_output object for the given wl_output.
+ */
+static inline struct zxdg_output_v1* zxdg_output_manager_v1_get_xdg_output(
+    struct zxdg_output_manager_v1* zxdg_output_manager_v1,
+    struct wl_output* output) {
+  struct wl_proxy* id;
+
+  id = wl_proxy_marshal_constructor((struct wl_proxy*)zxdg_output_manager_v1,
+                                    ZXDG_OUTPUT_MANAGER_V1_GET_XDG_OUTPUT,
+                                    &zxdg_output_v1_interface, NULL, output);
+
+  return (struct zxdg_output_v1*)id;
+}
+
+/**
+ * @ingroup iface_zxdg_output_v1
+ * @struct zxdg_output_v1_listener
+ */
+struct zxdg_output_v1_listener {
+  /**
+   * position of the output within the global compositor space
+   *
+   * The position event describes the location of the wl_output
+   * within the global compositor space.
+   *
+   * The logical_position event is sent after creating an xdg_output
+   * (see xdg_output_manager.get_xdg_output) and whenever the
+   * location of the output changes within the global compositor
+   * space.
+   * @param x x position within the global compositor space
+   * @param y y position within the global compositor space
+   */
+  void (*logical_position)(void* data, struct zxdg_output_v1* zxdg_output_v1,
+                           int32_t x, int32_t y);
+  /**
+   * size of the output in the global compositor space
+   *
+   * The logical_size event describes the size of the output in the
+   * global compositor space.
+   *
+   * For example, a surface without any buffer scale, transformation
+   * nor rotation set, with the size matching the logical_size will
+   * have the same size as the corresponding output when displayed.
+   *
+   * Most regular Wayland clients should not pay attention to the
+   * logical size and would rather rely on xdg_shell interfaces.
+   *
+   * Some clients such as Xwayland, however, need this to configure
+   * their surfaces in the global compositor space as the compositor
+   * may apply a different scale from what is advertised by the
+   * output scaling property (to achieve fractional scaling, for
+   * example).
+   *
+   * For example, for a wl_output mode 3840×2160 and a scale factor
+   * 2:
+   *
+   * - A compositor not scaling the surface buffers will advertise a
+   * logical size of 3840×2160,
+   *
+   * - A compositor automatically scaling the surface buffers will
+   * advertise a logical size of 1920×1080,
+   *
+   * - A compositor using a fractional scale of 1.5 will advertise a
+   * logical size to 2560×1620.
+   *
+   * For example, for a wl_output mode 1920×1080 and a 90 degree
+   * rotation, the compositor will advertise a logical size of
+   * 1080x1920.
+   *
+   * The logical_size event is sent after creating an xdg_output (see
+   * xdg_output_manager.get_xdg_output) and whenever the logical size
+   * of the output changes, either as a result of a change in the
+   * applied scale or because of a change in the corresponding output
+   * mode(see wl_output.mode) or transform (see wl_output.transform).
+   * @param width width in global compositor space
+   * @param height height in global compositor space
+   */
+  void (*logical_size)(void* data, struct zxdg_output_v1* zxdg_output_v1,
+                       int32_t width, int32_t height);
+  /**
+   * all information about the output have been sent
+   *
+   * This event is sent after all other properties of an xdg_output
+   * have been sent.
+   *
+   * This allows changes to the xdg_output properties to be seen as
+   * atomic, even if they happen via multiple events.
+   *
+   * For objects version 3 onwards, this event is deprecated.
+   * Compositors are not required to send it anymore and must send
+   * wl_output.done instead.
+   */
+  void (*done)(void* data, struct zxdg_output_v1* zxdg_output_v1);
+  /**
+   * name of this output
+   *
+   * Many compositors will assign names to their outputs, show them
+   * to the user, allow them to be configured by name, etc. The
+   * client may wish to know this name as well to offer the user
+   * similar behaviors.
+   *
+   * The naming convention is compositor defined, but limited to
+   * alphanumeric characters and dashes (-). Each name is unique
+   * among all wl_output globals, but if a wl_output global is
+   * destroyed the same name may be reused later. The names will also
+   * remain consistent across sessions with the same hardware and
+   * software configuration.
+   *
+   * Examples of names include 'HDMI-A-1', 'WL-1', 'X11-1', etc.
+   * However, do not assume that the name is a reflection of an
+   * underlying DRM connector, X11 connection, etc.
+   *
+   * The name event is sent after creating an xdg_output (see
+   * xdg_output_manager.get_xdg_output). This event is only sent once
+   * per xdg_output, and the name does not change over the lifetime
+   * of the wl_output global.
+   * @param name output name
+   * @since 2
+   */
+  void (*name)(void* data, struct zxdg_output_v1* zxdg_output_v1,
+               const char* name);
+  /**
+   * human-readable description of this output
+   *
+   * Many compositors can produce human-readable descriptions of
+   * their outputs. The client may wish to know this description as
+   * well, to communicate the user for various purposes.
+   *
+   * The description is a UTF-8 string with no convention defined for
+   * its contents. Examples might include 'Foocorp 11" Display' or
+   * 'Virtual X11 output via :1'.
+   *
+   * The description event is sent after creating an xdg_output (see
+   * xdg_output_manager.get_xdg_output) and whenever the description
+   * changes. The description is optional, and may not be sent at
+   * all.
+   *
+   * For objects of version 2 and lower, this event is only sent once
+   * per xdg_output, and the description does not change over the
+   * lifetime of the wl_output global.
+   * @param description output description
+   * @since 2
+   */
+  void (*description)(void* data, struct zxdg_output_v1* zxdg_output_v1,
+                      const char* description);
+};
+
+/**
+ * @ingroup iface_zxdg_output_v1
+ */
+static inline int zxdg_output_v1_add_listener(
+    struct zxdg_output_v1* zxdg_output_v1,
+    const struct zxdg_output_v1_listener* listener, void* data) {
+  return wl_proxy_add_listener((struct wl_proxy*)zxdg_output_v1,
+                               (void (**)(void))listener, data);
+}
+
+#define ZXDG_OUTPUT_V1_DESTROY 0
+
+/**
+ * @ingroup iface_zxdg_output_v1
+ */
+#define ZXDG_OUTPUT_V1_LOGICAL_POSITION_SINCE_VERSION 1
+/**
+ * @ingroup iface_zxdg_output_v1
+ */
+#define ZXDG_OUTPUT_V1_LOGICAL_SIZE_SINCE_VERSION 1
+/**
+ * @ingroup iface_zxdg_output_v1
+ */
+#define ZXDG_OUTPUT_V1_DONE_SINCE_VERSION 1
+/**
+ * @ingroup iface_zxdg_output_v1
+ */
+#define ZXDG_OUTPUT_V1_NAME_SINCE_VERSION 2
+/**
+ * @ingroup iface_zxdg_output_v1
+ */
+#define ZXDG_OUTPUT_V1_DESCRIPTION_SINCE_VERSION 2
+
+/**
+ * @ingroup iface_zxdg_output_v1
+ */
+#define ZXDG_OUTPUT_V1_DESTROY_SINCE_VERSION 1
+
+/** @ingroup iface_zxdg_output_v1 */
+static inline void zxdg_output_v1_set_user_data(
+    struct zxdg_output_v1* zxdg_output_v1, void* user_data) {
+  wl_proxy_set_user_data((struct wl_proxy*)zxdg_output_v1, user_data);
+}
+
+/** @ingroup iface_zxdg_output_v1 */
+static inline void* zxdg_output_v1_get_user_data(
+    struct zxdg_output_v1* zxdg_output_v1) {
+  return wl_proxy_get_user_data((struct wl_proxy*)zxdg_output_v1);
+}
+
+static inline uint32_t zxdg_output_v1_get_version(
+    struct zxdg_output_v1* zxdg_output_v1) {
+  return wl_proxy_get_version((struct wl_proxy*)zxdg_output_v1);
+}
+
+/**
+ * @ingroup iface_zxdg_output_v1
+ *
+ * Using this request a client can tell the server that it is not
+ * going to use the xdg_output object anymore.
+ */
+static inline void zxdg_output_v1_destroy(
+    struct zxdg_output_v1* zxdg_output_v1) {
+  wl_proxy_marshal((struct wl_proxy*)zxdg_output_v1, ZXDG_OUTPUT_V1_DESTROY);
+
+  wl_proxy_destroy((struct wl_proxy*)zxdg_output_v1);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/widget/gtk/wayland/xdg-output-unstable-v1-protocol.c b/widget/gtk/wayland/xdg-output-unstable-v1-protocol.c
new file mode 100644
index 0000000000..f80133f357
--- /dev/null
+++ b/widget/gtk/wayland/xdg-output-unstable-v1-protocol.c
@@ -0,0 +1,74 @@
+/* Generated by wayland-scanner 1.18.0 */
+
+/*
+ * Copyright © 2017 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <gdk/gdkwayland.h>
+#include "wayland-util.h"
+
+#ifndef __has_attribute
+#  define __has_attribute(x) 0 /* Compatibility with non-clang compilers. */
+#endif
+
+#if (__has_attribute(visibility) || defined(__GNUC__) && __GNUC__ >= 4)
+#  define WL_PRIVATE __attribute__((visibility("hidden")))
+#else
+#  define WL_PRIVATE
+#endif
+
+extern const struct wl_interface wl_output_interface;
+extern const struct wl_interface zxdg_output_v1_interface;
+
+static const struct wl_interface* xdg_output_unstable_v1_types[] = {
+    NULL,
+    NULL,
+    &zxdg_output_v1_interface,
+    &wl_output_interface,
+};
+
+static const struct wl_message zxdg_output_manager_v1_requests[] = {
+    {"destroy", "", xdg_output_unstable_v1_types + 0},
+    {"get_xdg_output", "no", xdg_output_unstable_v1_types + 2},
+};
+
+WL_PRIVATE const struct wl_interface zxdg_output_manager_v1_interface = {
+    "zxdg_output_manager_v1", 3, 2, zxdg_output_manager_v1_requests, 0, NULL,
+};
+
+static const struct wl_message zxdg_output_v1_requests[] = {
+    {"destroy", "", xdg_output_unstable_v1_types + 0},
+};
+
+static const struct wl_message zxdg_output_v1_events[] = {
+    {"logical_position", "ii", xdg_output_unstable_v1_types + 0},
+    {"logical_size", "ii", xdg_output_unstable_v1_types + 0},
+    {"done", "", xdg_output_unstable_v1_types + 0},
+    {"name", "2s", xdg_output_unstable_v1_types + 0},
+    {"description", "2s", xdg_output_unstable_v1_types + 0},
+};
+
+WL_PRIVATE const struct wl_interface zxdg_output_v1_interface = {
+    "zxdg_output_v1", 3, 1, zxdg_output_v1_requests, 5, zxdg_output_v1_events,
+};
diff --git a/widget/headless/HeadlessClipboard.cpp b/widget/headless/HeadlessClipboard.cpp
new file mode 100644
index 0000000000..be419af523
--- /dev/null
+++ b/widget/headless/HeadlessClipboard.cpp
@@ -0,0 +1,154 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HeadlessClipboard.h"
+
+#include "nsISupportsPrimitives.h"
+#include "nsComponentManagerUtils.h"
+#include "nsCOMPtr.h"
+
+namespace mozilla::widget {
+
+NS_IMPL_ISUPPORTS_INHERITED0(HeadlessClipboard, nsBaseClipboard)
+
+HeadlessClipboard::HeadlessClipboard()
+    : nsBaseClipboard(mozilla::dom::ClipboardCapabilities(
+          true /* supportsSelectionClipboard */,
+          true /* supportsFindClipboard */,
+          true /* supportsSelectionCache */)) {
+  for (auto& clipboard : mClipboards) {
+    clipboard = MakeUnique<HeadlessClipboardData>();
+  }
+}
+
+NS_IMETHODIMP
+HeadlessClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
+                                          int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  // Clear out the clipboard in order to set the new data.
+  EmptyNativeClipboardData(aWhichClipboard);
+
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanExport(flavors);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  auto& clipboard = mClipboards[aWhichClipboard];
+  MOZ_ASSERT(clipboard);
+
+  for (const auto& flavor : flavors) {
+    if (!flavor.EqualsLiteral(kTextMime) && !flavor.EqualsLiteral(kHTMLMime)) {
+      continue;
+    }
+
+    nsCOMPtr<nsISupports> data;
+    rv = aTransferable->GetTransferData(flavor.get(), getter_AddRefs(data));
+    if (NS_FAILED(rv)) {
+      continue;
+    }
+
+    nsCOMPtr<nsISupportsString> wideString = do_QueryInterface(data);
+    if (!wideString) {
+      continue;
+    }
+
+    nsAutoString utf16string;
+    wideString->GetData(utf16string);
+    flavor.EqualsLiteral(kTextMime) ? clipboard->SetText(utf16string)
+                                    : clipboard->SetHTML(utf16string);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+HeadlessClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
+                                          int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanImport(flavors);
+  if (NS_FAILED(rv)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  auto& clipboard = mClipboards[aWhichClipboard];
+  MOZ_ASSERT(clipboard);
+
+  for (const auto& flavor : flavors) {
+    if (!flavor.EqualsLiteral(kTextMime) && !flavor.EqualsLiteral(kHTMLMime)) {
+      continue;
+    }
+
+    bool isText = flavor.EqualsLiteral(kTextMime);
+    if (!(isText ? clipboard->HasText() : clipboard->HasHTML())) {
+      continue;
+    }
+
+    nsCOMPtr<nsISupportsString> dataWrapper =
+        do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID, &rv);
+    rv = dataWrapper->SetData(isText ? clipboard->GetText()
+                                     : clipboard->GetHTML());
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      continue;
+    }
+
+    nsCOMPtr<nsISupports> genericDataWrapper = do_QueryInterface(dataWrapper);
+    rv = aTransferable->SetTransferData(flavor.get(), genericDataWrapper);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      continue;
+    }
+
+    // XXX Other platforms only fill the first available type, too.
+    break;
+  }
+
+  return NS_OK;
+}
+
+nsresult HeadlessClipboard::EmptyNativeClipboardData(int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+  auto& clipboard = mClipboards[aWhichClipboard];
+  MOZ_ASSERT(clipboard);
+  clipboard->Clear();
+  return NS_OK;
+}
+
+mozilla::Result<int32_t, nsresult>
+HeadlessClipboard::GetNativeClipboardSequenceNumber(int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+  auto& clipboard = mClipboards[aWhichClipboard];
+  MOZ_ASSERT(clipboard);
+  return clipboard->GetChangeCount();
+  ;
+}
+
+mozilla::Result<bool, nsresult>
+HeadlessClipboard::HasNativeClipboardDataMatchingFlavors(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  auto& clipboard = mClipboards[aWhichClipboard];
+  MOZ_ASSERT(clipboard);
+
+  // Retrieve the union of all aHasType in aFlavorList
+  for (auto& flavor : aFlavorList) {
+    if ((flavor.EqualsLiteral(kTextMime) && clipboard->HasText()) ||
+        (flavor.EqualsLiteral(kHTMLMime) && clipboard->HasHTML())) {
+      return true;
+    }
+  }
+  return false;
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/headless/HeadlessClipboard.h b/widget/headless/HeadlessClipboard.h
new file mode 100644
index 0000000000..697fc78f8b
--- /dev/null
+++ b/widget/headless/HeadlessClipboard.h
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_HeadlessClipboard_h
+#define mozilla_widget_HeadlessClipboard_h
+
+#include "nsBaseClipboard.h"
+#include "nsIClipboard.h"
+#include "mozilla/UniquePtr.h"
+#include "HeadlessClipboardData.h"
+
+namespace mozilla {
+namespace widget {
+
+class HeadlessClipboard final : public nsBaseClipboard {
+ public:
+  HeadlessClipboard();
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+ protected:
+  ~HeadlessClipboard() = default;
+
+  // Implement the native clipboard behavior.
+  NS_IMETHOD SetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) override;
+  NS_IMETHOD GetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) override;
+  nsresult EmptyNativeClipboardData(int32_t aWhichClipboard) override;
+  mozilla::Result<int32_t, nsresult> GetNativeClipboardSequenceNumber(
+      int32_t aWhichClipboard) override;
+  mozilla::Result<bool, nsresult> HasNativeClipboardDataMatchingFlavors(
+      const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) override;
+
+ private:
+  UniquePtr<HeadlessClipboardData>
+      mClipboards[nsIClipboard::kClipboardTypeCount];
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/headless/HeadlessClipboardData.cpp b/widget/headless/HeadlessClipboardData.cpp
new file mode 100644
index 0000000000..8a10488403
--- /dev/null
+++ b/widget/headless/HeadlessClipboardData.cpp
@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HeadlessClipboardData.h"
+
+namespace mozilla::widget {
+
+void HeadlessClipboardData::SetText(const nsAString& aText) {
+  mPlain = aText;
+  mChangeCount++;
+}
+
+bool HeadlessClipboardData::HasText() const { return !mPlain.IsVoid(); }
+
+const nsAString& HeadlessClipboardData::GetText() const { return mPlain; }
+
+void HeadlessClipboardData::SetHTML(const nsAString& aHTML) {
+  mHTML = aHTML;
+  mChangeCount++;
+}
+
+bool HeadlessClipboardData::HasHTML() const { return !mHTML.IsVoid(); }
+
+const nsAString& HeadlessClipboardData::GetHTML() const { return mHTML; }
+
+int32_t HeadlessClipboardData::GetChangeCount() const { return mChangeCount; }
+
+void HeadlessClipboardData::Clear() {
+  mPlain.SetIsVoid(true);
+  mHTML.SetIsVoid(true);
+  mChangeCount++;
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/headless/HeadlessClipboardData.h b/widget/headless/HeadlessClipboardData.h
new file mode 100644
index 0000000000..6e9a0109e7
--- /dev/null
+++ b/widget/headless/HeadlessClipboardData.h
@@ -0,0 +1,44 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_HeadlessClipboardData_h
+#define mozilla_widget_HeadlessClipboardData_h
+
+#include "mozilla/RefPtr.h"
+#include "nsString.h"
+
+namespace mozilla {
+namespace widget {
+
+class HeadlessClipboardData final {
+ public:
+  HeadlessClipboardData() : mPlain(VoidString()), mHTML(VoidString()) {}
+  ~HeadlessClipboardData() = default;
+
+  // For text/plain
+  void SetText(const nsAString& aText);
+  bool HasText() const;
+  const nsAString& GetText() const;
+
+  // For text/html
+  void SetHTML(const nsAString& aHTML);
+  bool HasHTML() const;
+  const nsAString& GetHTML() const;
+
+  int32_t GetChangeCount() const;
+
+  // For other APIs
+  void Clear();
+
+ private:
+  nsString mPlain;
+  nsString mHTML;
+
+  int32_t mChangeCount = 0;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_HeadlessClipboardData_h
diff --git a/widget/headless/HeadlessCompositorWidget.cpp b/widget/headless/HeadlessCompositorWidget.cpp
new file mode 100644
index 0000000000..bb4ee9175e
--- /dev/null
+++ b/widget/headless/HeadlessCompositorWidget.cpp
@@ -0,0 +1,46 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "HeadlessCompositorWidget.h"
+#include "VsyncDispatcher.h"
+
+namespace mozilla {
+namespace widget {
+
+HeadlessCompositorWidget::HeadlessCompositorWidget(
+    const HeadlessCompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions, HeadlessWidget* aWindow)
+    : CompositorWidget(aOptions),
+      mWidget(aWindow),
+      mClientSize(LayoutDeviceIntSize(aInitData.InitialClientSize()),
+                  "HeadlessCompositorWidget::mClientSize") {}
+
+void HeadlessCompositorWidget::ObserveVsync(VsyncObserver* aObserver) {
+  if (RefPtr<CompositorVsyncDispatcher> cvd =
+          mWidget->GetCompositorVsyncDispatcher()) {
+    cvd->SetCompositorVsyncObserver(aObserver);
+  }
+}
+
+nsIWidget* HeadlessCompositorWidget::RealWidget() { return mWidget; }
+
+void HeadlessCompositorWidget::NotifyClientSizeChanged(
+    const LayoutDeviceIntSize& aClientSize) {
+  auto size = mClientSize.Lock();
+  *size = aClientSize;
+}
+
+LayoutDeviceIntSize HeadlessCompositorWidget::GetClientSize() {
+  auto size = mClientSize.Lock();
+  return *size;
+}
+
+uintptr_t HeadlessCompositorWidget::GetWidgetKey() {
+  return reinterpret_cast<uintptr_t>(mWidget);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/headless/HeadlessCompositorWidget.h b/widget/headless/HeadlessCompositorWidget.h
new file mode 100644
index 0000000000..facd2bc65a
--- /dev/null
+++ b/widget/headless/HeadlessCompositorWidget.h
@@ -0,0 +1,54 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_headless_HeadlessCompositorWidget_h
+#define widget_headless_HeadlessCompositorWidget_h
+
+#include "mozilla/widget/CompositorWidget.h"
+
+#include "HeadlessWidget.h"
+
+namespace mozilla {
+namespace widget {
+
+class HeadlessCompositorWidgetInitData;
+
+class HeadlessCompositorWidget final : public CompositorWidget,
+                                       public CompositorWidgetDelegate {
+ public:
+  HeadlessCompositorWidget(const HeadlessCompositorWidgetInitData& aInitData,
+                           const layers::CompositorOptions& aOptions,
+                           HeadlessWidget* aWindow);
+
+  void NotifyClientSizeChanged(const LayoutDeviceIntSize& aClientSize);
+
+  // CompositorWidget Overrides
+
+  uintptr_t GetWidgetKey() override;
+
+  LayoutDeviceIntSize GetClientSize() override;
+
+  nsIWidget* RealWidget() override;
+  CompositorWidgetDelegate* AsDelegate() override { return this; }
+
+  void ObserveVsync(VsyncObserver* aObserver) override;
+
+  // CompositorWidgetDelegate Overrides
+
+  HeadlessCompositorWidget* AsHeadlessCompositorWidget() override {
+    return this;
+  }
+
+ private:
+  HeadlessWidget* mWidget;
+
+  // See GtkCompositorWidget for the justification for this mutex.
+  DataMutex<LayoutDeviceIntSize> mClientSize;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_headless_HeadlessCompositor_h
diff --git a/widget/headless/HeadlessKeyBindings.cpp b/widget/headless/HeadlessKeyBindings.cpp
new file mode 100644
index 0000000000..13fcd4c6ca
--- /dev/null
+++ b/widget/headless/HeadlessKeyBindings.cpp
@@ -0,0 +1,37 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HeadlessKeyBindings.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/WritingModes.h"
+
+namespace mozilla {
+namespace widget {
+
+HeadlessKeyBindings& HeadlessKeyBindings::GetInstance() {
+  static UniquePtr<HeadlessKeyBindings> sInstance;
+  if (!sInstance) {
+    sInstance.reset(new HeadlessKeyBindings());
+    ClearOnShutdown(&sInstance);
+  }
+  return *sInstance;
+}
+
+nsresult HeadlessKeyBindings::AttachNativeKeyEvent(
+    WidgetKeyboardEvent& aEvent) {
+  // Stub for non-mac platforms.
+  return NS_OK;
+}
+
+void HeadlessKeyBindings::GetEditCommands(
+    NativeKeyBindingsType aType, const WidgetKeyboardEvent& aEvent,
+    const Maybe<WritingMode>& aWritingMode, nsTArray<CommandInt>& aCommands) {
+  // Stub for non-mac platforms.
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/headless/HeadlessKeyBindings.h b/widget/headless/HeadlessKeyBindings.h
new file mode 100644
index 0000000000..5eff30c4f5
--- /dev/null
+++ b/widget/headless/HeadlessKeyBindings.h
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_HeadlessKeyBindings_h
+#define mozilla_widget_HeadlessKeyBindings_h
+
+#include "mozilla/TextEvents.h"
+#include "nsIWidget.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+enum class NativeKeyBindingsType : uint8_t;
+
+class WritingMode;
+template <typename T>
+class Maybe;
+
+namespace widget {
+
+/**
+ * Helper to emulate native key bindings. Currently only MacOS is supported.
+ */
+
+class HeadlessKeyBindings final {
+ public:
+  HeadlessKeyBindings() = default;
+
+  static HeadlessKeyBindings& GetInstance();
+
+  void GetEditCommands(NativeKeyBindingsType aType,
+                       const WidgetKeyboardEvent& aEvent,
+                       const Maybe<WritingMode>& aWritingMode,
+                       nsTArray<CommandInt>& aCommands);
+  [[nodiscard]] nsresult AttachNativeKeyEvent(WidgetKeyboardEvent& aEvent);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_HeadlessKeyBindings_h
diff --git a/widget/headless/HeadlessKeyBindingsCocoa.mm b/widget/headless/HeadlessKeyBindingsCocoa.mm
new file mode 100644
index 0000000000..27ed07c461
--- /dev/null
+++ b/widget/headless/HeadlessKeyBindingsCocoa.mm
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HeadlessKeyBindings.h"
+#import <Cocoa/Cocoa.h>
+#include "nsCocoaUtils.h"
+#include "NativeKeyBindings.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/WritingModes.h"
+
+namespace mozilla {
+namespace widget {
+
+HeadlessKeyBindings& HeadlessKeyBindings::GetInstance() {
+  static UniquePtr<HeadlessKeyBindings> sInstance;
+  if (!sInstance) {
+    sInstance.reset(new HeadlessKeyBindings());
+    ClearOnShutdown(&sInstance);
+  }
+  return *sInstance;
+}
+
+nsresult HeadlessKeyBindings::AttachNativeKeyEvent(
+    WidgetKeyboardEvent& aEvent) {
+  NS_OBJC_BEGIN_TRY_BLOCK_RETURN;
+
+  aEvent.mNativeKeyEvent =
+      nsCocoaUtils::MakeNewCococaEventFromWidgetEvent(aEvent, 0, nil);
+
+  return NS_OK;
+
+  NS_OBJC_END_TRY_BLOCK_RETURN(NS_ERROR_FAILURE);
+}
+
+void HeadlessKeyBindings::GetEditCommands(
+    NativeKeyBindingsType aType, const WidgetKeyboardEvent& aEvent,
+    const Maybe<WritingMode>& aWritingMode, nsTArray<CommandInt>& aCommands) {
+  // Convert the widget keyboard into a cocoa event so it can be translated
+  // into commands in the NativeKeyBindings.
+  WidgetKeyboardEvent modifiedEvent(aEvent);
+  modifiedEvent.mNativeKeyEvent =
+      nsCocoaUtils::MakeNewCococaEventFromWidgetEvent(aEvent, 0, nil);
+
+  NativeKeyBindings* keyBindings = NativeKeyBindings::GetInstance(aType);
+  keyBindings->GetEditCommands(modifiedEvent, aWritingMode, aCommands);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/headless/HeadlessLookAndFeel.h b/widget/headless/HeadlessLookAndFeel.h
new file mode 100644
index 0000000000..4e61b9e95d
--- /dev/null
+++ b/widget/headless/HeadlessLookAndFeel.h
@@ -0,0 +1,58 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_HeadlessLookAndFeel_h
+#define mozilla_widget_HeadlessLookAndFeel_h
+
+#include "nsXPLookAndFeel.h"
+#include "nsLookAndFeel.h"
+
+namespace mozilla {
+namespace widget {
+
+#if defined(MOZ_WIDGET_GTK)
+
+// Our nsLookAndFeel for Gtk relies on APIs that aren't available in headless
+// mode, so for processes that are unable to connect to a display server, we use
+// an implementation with hardcoded values.
+//
+// HeadlessLookAndFeel is used:
+//
+//   * in the parent process, when full headless mode (MOZ_HEADLESS=1) is
+//     enabled
+//
+// The result of this is that when headless content mode is enabled, content
+// processes use values derived from the parent's nsLookAndFeel (i.e., values
+// derived from Gtk APIs) while still refraining from making any display server
+// connections.
+
+class HeadlessLookAndFeel : public nsXPLookAndFeel {
+ public:
+  explicit HeadlessLookAndFeel();
+  virtual ~HeadlessLookAndFeel();
+
+  void NativeInit() final{};
+  nsresult NativeGetInt(IntID, int32_t& aResult) override;
+  nsresult NativeGetFloat(FloatID, float& aResult) override;
+  nsresult NativeGetColor(ColorID, ColorScheme, nscolor& aResult) override;
+  bool NativeGetFont(FontID, nsString& aFontName, gfxFontStyle&) override;
+
+  char16_t GetPasswordCharacterImpl() override;
+};
+
+#else
+
+// When possible, we simply reuse the platform's existing nsLookAndFeel
+// implementation in headless mode.
+
+typedef nsLookAndFeel HeadlessLookAndFeel;
+
+#endif
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/headless/HeadlessLookAndFeelGTK.cpp b/widget/headless/HeadlessLookAndFeelGTK.cpp
new file mode 100644
index 0000000000..f8f6270cd7
--- /dev/null
+++ b/widget/headless/HeadlessLookAndFeelGTK.cpp
@@ -0,0 +1,223 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HeadlessLookAndFeel.h"
+#include "mozilla/FontPropertyTypes.h"
+#include "nsIContent.h"
+
+namespace mozilla::widget {
+
+static const char16_t UNICODE_BULLET = 0x2022;
+
+HeadlessLookAndFeel::HeadlessLookAndFeel() = default;
+
+HeadlessLookAndFeel::~HeadlessLookAndFeel() = default;
+
+nsresult HeadlessLookAndFeel::NativeGetColor(ColorID aID, ColorScheme aScheme,
+                                             nscolor& aResult) {
+  aResult = GetStandinForNativeColor(aID, aScheme);
+  return NS_OK;
+}
+
+nsresult HeadlessLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
+  nsresult res = NS_OK;
+  // These values should be sane defaults for headless mode under GTK.
+  switch (aID) {
+    case IntID::CaretBlinkTime:
+      aResult = 567;
+      break;
+    case IntID::CaretWidth:
+      aResult = 1;
+      break;
+    case IntID::ShowCaretDuringSelection:
+      aResult = 0;
+      break;
+    case IntID::SelectTextfieldsOnKeyFocus:
+      aResult = 1;
+      break;
+    case IntID::SubmenuDelay:
+      aResult = 200;
+      break;
+    case IntID::MenusCanOverlapOSBar:
+      aResult = 0;
+      break;
+    case IntID::UseOverlayScrollbars:
+      aResult = 0;
+      break;
+    case IntID::AllowOverlayScrollbarsOverlap:
+      aResult = 0;
+      break;
+    case IntID::SkipNavigatingDisabledMenuItem:
+      aResult = 1;
+      break;
+    case IntID::DragThresholdX:
+    case IntID::DragThresholdY:
+      aResult = 4;
+      break;
+    case IntID::UseAccessibilityTheme:
+      aResult = 0;
+      break;
+    case IntID::ScrollArrowStyle:
+      aResult = eScrollArrow_None;
+      break;
+    case IntID::ScrollButtonLeftMouseButtonAction:
+      aResult = 0;
+      return NS_OK;
+    case IntID::ScrollButtonMiddleMouseButtonAction:
+      aResult = 3;
+      return NS_OK;
+    case IntID::ScrollButtonRightMouseButtonAction:
+      aResult = 3;
+      return NS_OK;
+    case IntID::TreeOpenDelay:
+      aResult = 1000;
+      break;
+    case IntID::TreeCloseDelay:
+      aResult = 1000;
+      break;
+    case IntID::TreeLazyScrollDelay:
+      aResult = 150;
+      break;
+    case IntID::TreeScrollDelay:
+      aResult = 100;
+      break;
+    case IntID::TreeScrollLinesMax:
+      aResult = 3;
+      break;
+    case IntID::TabFocusModel:
+      aResult = nsIContent::eTabFocus_textControlsMask;
+      break;
+    case IntID::ChosenMenuItemsShouldBlink:
+      aResult = 1;
+      break;
+    case IntID::WindowsAccentColorInTitlebar:
+      aResult = 0;
+      res = NS_ERROR_NOT_IMPLEMENTED;
+      break;
+    case IntID::AlertNotificationOrigin:
+      aResult = NS_ALERT_TOP;
+      break;
+    case IntID::ScrollToClick:
+      aResult = 0;
+      break;
+    case IntID::IMERawInputUnderlineStyle:
+    case IntID::IMESelectedRawTextUnderlineStyle:
+    case IntID::IMEConvertedTextUnderlineStyle:
+    case IntID::IMESelectedConvertedTextUnderline:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Solid);
+      break;
+    case IntID::SpellCheckerUnderlineStyle:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Dotted);
+      break;
+    case IntID::MenuBarDrag:
+      aResult = 0;
+      break;
+    case IntID::ScrollbarButtonAutoRepeatBehavior:
+      aResult = 0;
+      break;
+    case IntID::TooltipDelay:
+      aResult = 500;
+      break;
+    case IntID::SwipeAnimationEnabled:
+      aResult = 0;
+      break;
+    case IntID::ScrollbarDisplayOnMouseMove:
+      aResult = 0;
+      break;
+    case IntID::ScrollbarFadeBeginDelay:
+      aResult = 0;
+      break;
+    case IntID::ScrollbarFadeDuration:
+      aResult = 0;
+      break;
+    case IntID::ContextMenuOffsetVertical:
+      aResult = -6;
+      break;
+    case IntID::ContextMenuOffsetHorizontal:
+      aResult = 1;
+      break;
+    case IntID::GTKCSDAvailable:
+      aResult = 0;
+      break;
+    case IntID::GTKCSDMinimizeButton:
+      aResult = 0;
+      break;
+    case IntID::GTKCSDMaximizeButton:
+      aResult = 0;
+      break;
+    case IntID::GTKCSDCloseButton:
+      aResult = 1;
+      break;
+    case IntID::GTKCSDReversedPlacement:
+      aResult = 0;
+      break;
+    case IntID::SystemUsesDarkTheme:
+      aResult = 0;
+      break;
+    case IntID::PrefersReducedMotion:
+    case IntID::PrefersReducedTransparency:
+      aResult = 0;
+      break;
+    case IntID::InvertedColors:
+      aResult = 0;
+      break;
+    case IntID::PrimaryPointerCapabilities:
+      aResult = 0;
+      break;
+    case IntID::AllPointerCapabilities:
+      aResult = 0;
+      break;
+    default:
+      aResult = 0;
+      res = NS_ERROR_FAILURE;
+      break;
+  }
+  return res;
+}
+
+nsresult HeadlessLookAndFeel::NativeGetFloat(FloatID aID, float& aResult) {
+  nsresult res = NS_OK;
+
+  // Hardcoded values for GTK.
+  switch (aID) {
+    case FloatID::IMEUnderlineRelativeSize:
+      aResult = 1.0f;
+      break;
+    case FloatID::SpellCheckerUnderlineRelativeSize:
+      aResult = 1.0f;
+      break;
+    case FloatID::CaretAspectRatio:
+      // Intentionally failing to quietly indicate lack of support.
+      aResult = -1.0;
+      res = NS_ERROR_FAILURE;
+      break;
+    default:
+      aResult = -1.0;
+      res = NS_ERROR_FAILURE;
+      break;
+  }
+
+  return res;
+}
+
+bool HeadlessLookAndFeel::NativeGetFont(FontID aID, nsString& aFontName,
+                                        gfxFontStyle& aFontStyle) {
+  // Default to san-serif for everything.
+  aFontStyle.style = FontSlantStyle::NORMAL;
+  aFontStyle.weight = FontWeight::NORMAL;
+  aFontStyle.stretch = FontStretch::NORMAL;
+  aFontStyle.size = 14;
+  aFontStyle.systemFont = true;
+
+  aFontName.AssignLiteral("sans-serif");
+  return true;
+}
+
+char16_t HeadlessLookAndFeel::GetPasswordCharacterImpl() {
+  return UNICODE_BULLET;
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/headless/HeadlessScreenHelper.cpp b/widget/headless/HeadlessScreenHelper.cpp
new file mode 100644
index 0000000000..4d8dbfa0d1
--- /dev/null
+++ b/widget/headless/HeadlessScreenHelper.cpp
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HeadlessScreenHelper.h"
+
+#include "prenv.h"
+#include "mozilla/dom/DOMTypes.h"
+#include "mozilla/RefPtr.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+namespace widget {
+
+/* static */
+LayoutDeviceIntRect HeadlessScreenHelper::GetScreenRect() {
+  char* ev = PR_GetEnv("MOZ_HEADLESS_WIDTH");
+  int width = 1366;
+  if (ev) {
+    width = atoi(ev);
+  }
+  ev = PR_GetEnv("MOZ_HEADLESS_HEIGHT");
+  int height = 768;
+  if (ev) {
+    height = atoi(ev);
+  }
+  return LayoutDeviceIntRect(0, 0, width, height);
+}
+
+HeadlessScreenHelper::HeadlessScreenHelper() {
+  AutoTArray<RefPtr<Screen>, 1> screenList;
+  LayoutDeviceIntRect rect = GetScreenRect();
+  auto ret = MakeRefPtr<Screen>(
+      rect, rect, 24, 24, 0, DesktopToLayoutDeviceScale(),
+      CSSToLayoutDeviceScale(), 96.0f, Screen::IsPseudoDisplay::No);
+  screenList.AppendElement(ret.forget());
+  ScreenManager::Refresh(std::move(screenList));
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/headless/HeadlessScreenHelper.h b/widget/headless/HeadlessScreenHelper.h
new file mode 100644
index 0000000000..f86677af52
--- /dev/null
+++ b/widget/headless/HeadlessScreenHelper.h
@@ -0,0 +1,27 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_HeadlessScreenHelper_h
+#define mozilla_widget_HeadlessScreenHelper_h
+
+#include "mozilla/widget/ScreenManager.h"
+
+namespace mozilla {
+namespace widget {
+
+class HeadlessScreenHelper final : public ScreenManager::Helper {
+ public:
+  HeadlessScreenHelper();
+  ~HeadlessScreenHelper() override = default;
+
+ private:
+  static LayoutDeviceIntRect GetScreenRect();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_HeadlessScreenHelper_h
diff --git a/widget/headless/HeadlessSound.cpp b/widget/headless/HeadlessSound.cpp
new file mode 100644
index 0000000000..278d31b355
--- /dev/null
+++ b/widget/headless/HeadlessSound.cpp
@@ -0,0 +1,36 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HeadlessSound.h"
+
+namespace mozilla {
+namespace widget {
+
+NS_IMPL_ISUPPORTS(HeadlessSound, nsISound, nsIStreamLoaderObserver)
+
+HeadlessSound::HeadlessSound() = default;
+
+HeadlessSound::~HeadlessSound() = default;
+
+NS_IMETHODIMP
+HeadlessSound::Init() { return NS_OK; }
+
+NS_IMETHODIMP HeadlessSound::OnStreamComplete(nsIStreamLoader* aLoader,
+                                              nsISupports* context,
+                                              nsresult aStatus,
+                                              uint32_t dataLen,
+                                              const uint8_t* data) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP HeadlessSound::Beep() { return NS_OK; }
+
+NS_IMETHODIMP HeadlessSound::Play(nsIURL* aURL) { return NS_OK; }
+
+NS_IMETHODIMP HeadlessSound::PlayEventSound(uint32_t aEventId) { return NS_OK; }
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/headless/HeadlessSound.h b/widget/headless/HeadlessSound.h
new file mode 100644
index 0000000000..a481acc61e
--- /dev/null
+++ b/widget/headless/HeadlessSound.h
@@ -0,0 +1,31 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_HeadlessSound_h
+#define mozilla_widget_HeadlessSound_h
+
+#include "nsISound.h"
+#include "nsIStreamLoader.h"
+
+namespace mozilla {
+namespace widget {
+
+class HeadlessSound : public nsISound, public nsIStreamLoaderObserver {
+ public:
+  HeadlessSound();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISOUND
+  NS_DECL_NSISTREAMLOADEROBSERVER
+
+ private:
+  virtual ~HeadlessSound();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_HeadlessSound_h
diff --git a/widget/headless/HeadlessWidget.cpp b/widget/headless/HeadlessWidget.cpp
new file mode 100644
index 0000000000..083d026d3c
--- /dev/null
+++ b/widget/headless/HeadlessWidget.cpp
@@ -0,0 +1,625 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "HeadlessWidget.h"
+#include "ErrorList.h"
+#include "HeadlessCompositorWidget.h"
+#include "BasicEvents.h"
+#include "MouseEvents.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/WritingModes.h"
+#include "mozilla/widget/HeadlessWidgetTypes.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "mozilla/widget/Screen.h"
+#include "nsIScreen.h"
+#include "HeadlessKeyBindings.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using namespace mozilla::layers;
+
+using mozilla::LogLevel;
+
+#ifdef MOZ_LOGGING
+
+#  include "mozilla/Logging.h"
+static mozilla::LazyLogModule sWidgetLog("Widget");
+static mozilla::LazyLogModule sWidgetFocusLog("WidgetFocus");
+#  define LOG(args) MOZ_LOG(sWidgetLog, mozilla::LogLevel::Debug, args)
+#  define LOGFOCUS(args) \
+    MOZ_LOG(sWidgetFocusLog, mozilla::LogLevel::Debug, args)
+
+#else
+
+#  define LOG(args)
+#  define LOGFOCUS(args)
+
+#endif /* MOZ_LOGGING */
+
+/*static*/
+already_AddRefed<nsIWidget> nsIWidget::CreateHeadlessWidget() {
+  nsCOMPtr<nsIWidget> widget = new mozilla::widget::HeadlessWidget();
+  return widget.forget();
+}
+
+namespace mozilla {
+namespace widget {
+
+StaticAutoPtr<nsTArray<HeadlessWidget*>> HeadlessWidget::sActiveWindows;
+
+already_AddRefed<HeadlessWidget> HeadlessWidget::GetActiveWindow() {
+  if (!sActiveWindows) {
+    return nullptr;
+  }
+  auto length = sActiveWindows->Length();
+  if (length == 0) {
+    return nullptr;
+  }
+  RefPtr<HeadlessWidget> widget = sActiveWindows->ElementAt(length - 1);
+  return widget.forget();
+}
+
+HeadlessWidget::HeadlessWidget()
+    : mEnabled(true),
+      mVisible(false),
+      mDestroyed(false),
+      mAlwaysOnTop(false),
+      mTopLevel(nullptr),
+      mCompositorWidget(nullptr),
+      mSizeMode(nsSizeMode_Normal),
+      mLastSizeMode(nsSizeMode_Normal),
+      mEffectiveSizeMode(nsSizeMode_Normal),
+      mRestoreBounds(0, 0, 0, 0) {
+  if (!sActiveWindows) {
+    sActiveWindows = new nsTArray<HeadlessWidget*>();
+    ClearOnShutdown(&sActiveWindows);
+  }
+}
+
+HeadlessWidget::~HeadlessWidget() {
+  LOG(("HeadlessWidget::~HeadlessWidget() [%p]\n", (void*)this));
+
+  Destroy();
+}
+
+void HeadlessWidget::Destroy() {
+  if (mDestroyed) {
+    return;
+  }
+  LOG(("HeadlessWidget::Destroy [%p]\n", (void*)this));
+  mDestroyed = true;
+
+  if (sActiveWindows) {
+    int32_t index = sActiveWindows->IndexOf(this);
+    if (index != -1) {
+      RefPtr<HeadlessWidget> activeWindow = GetActiveWindow();
+      sActiveWindows->RemoveElementAt(index);
+      // If this is the currently active widget and there's a previously active
+      // widget, activate the previous widget.
+      RefPtr<HeadlessWidget> previousActiveWindow = GetActiveWindow();
+      if (this == activeWindow && previousActiveWindow &&
+          previousActiveWindow->mWidgetListener) {
+        previousActiveWindow->mWidgetListener->WindowActivated();
+      }
+    }
+  }
+
+  nsBaseWidget::OnDestroy();
+
+  nsBaseWidget::Destroy();
+}
+
+nsresult HeadlessWidget::Create(nsIWidget* aParent,
+                                nsNativeWidget aNativeParent,
+                                const LayoutDeviceIntRect& aRect,
+                                widget::InitData* aInitData) {
+  MOZ_ASSERT(!aNativeParent, "No native parents for headless widgets.");
+
+  BaseCreate(nullptr, aInitData);
+
+  mBounds = aRect;
+  mRestoreBounds = aRect;
+
+  mAlwaysOnTop = aInitData && aInitData->mAlwaysOnTop;
+
+  if (aParent) {
+    mTopLevel = aParent->GetTopLevelWidget();
+  } else {
+    mTopLevel = this;
+  }
+
+  return NS_OK;
+}
+
+already_AddRefed<nsIWidget> HeadlessWidget::CreateChild(
+    const LayoutDeviceIntRect& aRect, widget::InitData* aInitData,
+    bool aForceUseIWidgetParent) {
+  nsCOMPtr<nsIWidget> widget = nsIWidget::CreateHeadlessWidget();
+  if (!widget) {
+    return nullptr;
+  }
+  if (NS_FAILED(widget->Create(this, nullptr, aRect, aInitData))) {
+    return nullptr;
+  }
+  return widget.forget();
+}
+
+void HeadlessWidget::GetCompositorWidgetInitData(
+    mozilla::widget::CompositorWidgetInitData* aInitData) {
+  *aInitData =
+      mozilla::widget::HeadlessCompositorWidgetInitData(GetClientSize());
+}
+
+nsIWidget* HeadlessWidget::GetTopLevelWidget() { return mTopLevel; }
+
+void HeadlessWidget::RaiseWindow() {
+  MOZ_ASSERT(mWindowType == WindowType::TopLevel ||
+                 mWindowType == WindowType::Dialog ||
+                 mWindowType == WindowType::Sheet,
+             "Raising a non-toplevel window.");
+
+  // Do nothing if this is the currently active window.
+  RefPtr<HeadlessWidget> activeWindow = GetActiveWindow();
+  if (activeWindow == this) {
+    return;
+  }
+
+  // Raise the window to the top of the stack.
+  nsWindowZ placement = nsWindowZTop;
+  nsCOMPtr<nsIWidget> actualBelow;
+  if (mWidgetListener)
+    mWidgetListener->ZLevelChanged(true, &placement, nullptr,
+                                   getter_AddRefs(actualBelow));
+
+  // Deactivate the last active window.
+  if (activeWindow && activeWindow->mWidgetListener) {
+    activeWindow->mWidgetListener->WindowDeactivated();
+  }
+
+  // Remove this window if it's already tracked.
+  int32_t index = sActiveWindows->IndexOf(this);
+  if (index != -1) {
+    sActiveWindows->RemoveElementAt(index);
+  }
+
+  // Activate this window.
+  sActiveWindows->AppendElement(this);
+  if (mWidgetListener) mWidgetListener->WindowActivated();
+}
+
+void HeadlessWidget::Show(bool aState) {
+  mVisible = aState;
+
+  LOG(("HeadlessWidget::Show [%p] state %d\n", (void*)this, aState));
+
+  // Top-level window and dialogs are activated/raised when shown.
+  // NB: alwaysontop windows are generally used for peripheral indicators,
+  //     so we don't focus them by default.
+  if (aState && !mAlwaysOnTop &&
+      (mWindowType == WindowType::TopLevel ||
+       mWindowType == WindowType::Dialog || mWindowType == WindowType::Sheet)) {
+    RaiseWindow();
+  }
+
+  ApplySizeModeSideEffects();
+}
+
+bool HeadlessWidget::IsVisible() const { return mVisible; }
+
+void HeadlessWidget::SetFocus(Raise aRaise,
+                              mozilla::dom::CallerType aCallerType) {
+  LOGFOCUS(("  SetFocus %d [%p]\n", aRaise == Raise::Yes, (void*)this));
+
+  // This means we request activation of our toplevel window.
+  if (aRaise == Raise::Yes) {
+    HeadlessWidget* topLevel = (HeadlessWidget*)GetTopLevelWidget();
+
+    // The toplevel only becomes active if it's currently visible; otherwise, it
+    // will be activated anyway when it's shown.
+    if (topLevel->IsVisible()) topLevel->RaiseWindow();
+  }
+}
+
+void HeadlessWidget::Enable(bool aState) { mEnabled = aState; }
+
+bool HeadlessWidget::IsEnabled() const { return mEnabled; }
+
+void HeadlessWidget::Move(double aX, double aY) {
+  LOG(("HeadlessWidget::Move [%p] %f %f\n", (void*)this, aX, aY));
+
+  double scale =
+      BoundsUseDesktopPixels() ? GetDesktopToDeviceScale().scale : 1.0;
+  int32_t x = NSToIntRound(aX * scale);
+  int32_t y = NSToIntRound(aY * scale);
+
+  if (mWindowType == WindowType::TopLevel ||
+      mWindowType == WindowType::Dialog) {
+    SetSizeMode(nsSizeMode_Normal);
+  }
+
+  MoveInternal(x, y);
+}
+
+void HeadlessWidget::MoveInternal(int32_t aX, int32_t aY) {
+  // Since a popup window's x/y coordinates are in relation to
+  // the parent, the parent might have moved so we always move a
+  // popup window.
+  if (mBounds.IsEqualXY(aX, aY) && mWindowType != WindowType::Popup) {
+    return;
+  }
+
+  mBounds.MoveTo(aX, aY);
+  NotifyWindowMoved(aX, aY);
+}
+
+LayoutDeviceIntPoint HeadlessWidget::WidgetToScreenOffset() {
+  return mTopLevel->GetBounds().TopLeft();
+}
+
+WindowRenderer* HeadlessWidget::GetWindowRenderer() {
+  return nsBaseWidget::GetWindowRenderer();
+}
+
+void HeadlessWidget::SetCompositorWidgetDelegate(
+    CompositorWidgetDelegate* delegate) {
+  if (delegate) {
+    mCompositorWidget = delegate->AsHeadlessCompositorWidget();
+    MOZ_ASSERT(mCompositorWidget,
+               "HeadlessWidget::SetCompositorWidgetDelegate called with a "
+               "non-HeadlessCompositorWidget");
+  } else {
+    mCompositorWidget = nullptr;
+  }
+}
+
+void HeadlessWidget::Resize(double aWidth, double aHeight, bool aRepaint) {
+  int32_t width = NSToIntRound(aWidth);
+  int32_t height = NSToIntRound(aHeight);
+  ResizeInternal(width, height, aRepaint);
+}
+
+void HeadlessWidget::ResizeInternal(int32_t aWidth, int32_t aHeight,
+                                    bool aRepaint) {
+  ConstrainSize(&aWidth, &aHeight);
+  mBounds.SizeTo(LayoutDeviceIntSize(aWidth, aHeight));
+
+  if (mCompositorWidget) {
+    mCompositorWidget->NotifyClientSizeChanged(
+        LayoutDeviceIntSize(mBounds.Width(), mBounds.Height()));
+  }
+  if (mWidgetListener) {
+    mWidgetListener->WindowResized(this, mBounds.Width(), mBounds.Height());
+  }
+  if (mAttachedWidgetListener) {
+    mAttachedWidgetListener->WindowResized(this, mBounds.Width(),
+                                           mBounds.Height());
+  }
+}
+
+void HeadlessWidget::Resize(double aX, double aY, double aWidth, double aHeight,
+                            bool aRepaint) {
+  MoveInternal(NSToIntRound(aX), NSToIntRound(aY));
+  Resize(aWidth, aHeight, aRepaint);
+}
+
+void HeadlessWidget::SetSizeMode(nsSizeMode aMode) {
+  LOG(("HeadlessWidget::SetSizeMode [%p] %d\n", (void*)this, aMode));
+
+  if (aMode == mSizeMode) {
+    return;
+  }
+
+  if (aMode == nsSizeMode_Normal && mSizeMode == nsSizeMode_Fullscreen) {
+    MakeFullScreen(false);
+    return;
+  }
+
+  mSizeMode = aMode;
+
+  // Normally in real widget backends a window event would be triggered that
+  // would cause the window manager to handle resizing the window. In headless
+  // the window must manually be resized.
+  ApplySizeModeSideEffects();
+}
+
+void HeadlessWidget::ApplySizeModeSideEffects() {
+  if (!mVisible || mEffectiveSizeMode == mSizeMode) {
+    return;
+  }
+
+  if (mEffectiveSizeMode == nsSizeMode_Normal) {
+    // Store the last normal size bounds so it can be restored when entering
+    // normal mode again.
+    mRestoreBounds = mBounds;
+  }
+
+  switch (mSizeMode) {
+    case nsSizeMode_Normal: {
+      MoveInternal(mRestoreBounds.X(), mRestoreBounds.Y());
+      ResizeInternal(mRestoreBounds.Width(), mRestoreBounds.Height(), false);
+      break;
+    }
+    case nsSizeMode_Minimized:
+      break;
+    case nsSizeMode_Maximized: {
+      nsCOMPtr<nsIScreen> screen = GetWidgetScreen();
+      if (screen) {
+        int32_t left, top, width, height;
+        if (NS_SUCCEEDED(
+                screen->GetRectDisplayPix(&left, &top, &width, &height))) {
+          MoveInternal(0, 0);
+          ResizeInternal(width, height, true);
+        }
+      }
+      break;
+    }
+    case nsSizeMode_Fullscreen:
+      // This will take care of resizing the window.
+      nsBaseWidget::InfallibleMakeFullScreen(true);
+      break;
+    default:
+      break;
+  }
+
+  mEffectiveSizeMode = mSizeMode;
+  if (mWidgetListener) {
+    mWidgetListener->SizeModeChanged(mSizeMode);
+  }
+}
+
+nsresult HeadlessWidget::MakeFullScreen(bool aFullScreen) {
+  // Directly update the size mode here so a later call SetSizeMode does
+  // nothing.
+  if (aFullScreen) {
+    if (mSizeMode != nsSizeMode_Fullscreen) {
+      mLastSizeMode = mSizeMode;
+    }
+    mSizeMode = nsSizeMode_Fullscreen;
+  } else {
+    mSizeMode = mLastSizeMode;
+  }
+
+  // Notify the listener first so size mode change events are triggered before
+  // resize events.
+  if (mWidgetListener) {
+    mWidgetListener->SizeModeChanged(mSizeMode);
+  }
+
+  // Real widget backends don't seem to follow a common approach for
+  // when and how many resize events are triggered during fullscreen
+  // transitions. InfallibleMakeFullScreen will trigger a resize, but it
+  // will be ignored if still transitioning to fullscreen, so it must be
+  // triggered on the next tick.
+  RefPtr<HeadlessWidget> self(this);
+  NS_DispatchToCurrentThread(NS_NewRunnableFunction(
+      "HeadlessWidget::MakeFullScreen", [self, aFullScreen]() -> void {
+        self->InfallibleMakeFullScreen(aFullScreen);
+      }));
+
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::AttachNativeKeyEvent(WidgetKeyboardEvent& aEvent) {
+  HeadlessKeyBindings& bindings = HeadlessKeyBindings::GetInstance();
+  return bindings.AttachNativeKeyEvent(aEvent);
+}
+
+bool HeadlessWidget::GetEditCommands(NativeKeyBindingsType aType,
+                                     const WidgetKeyboardEvent& aEvent,
+                                     nsTArray<CommandInt>& aCommands) {
+  // Validate the arguments.
+  if (NS_WARN_IF(!nsIWidget::GetEditCommands(aType, aEvent, aCommands))) {
+    return false;
+  }
+
+  Maybe<WritingMode> writingMode;
+  if (aEvent.NeedsToRemapNavigationKey()) {
+    if (RefPtr<TextEventDispatcher> dispatcher = GetTextEventDispatcher()) {
+      writingMode = dispatcher->MaybeQueryWritingModeAtSelection();
+    }
+  }
+
+  HeadlessKeyBindings& bindings = HeadlessKeyBindings::GetInstance();
+  bindings.GetEditCommands(aType, aEvent, writingMode, aCommands);
+  return true;
+}
+
+nsresult HeadlessWidget::DispatchEvent(WidgetGUIEvent* aEvent,
+                                       nsEventStatus& aStatus) {
+#ifdef DEBUG
+  debug_DumpEvent(stdout, aEvent->mWidget, aEvent, "HeadlessWidget", 0);
+#endif
+
+  aStatus = nsEventStatus_eIgnore;
+
+  if (mAttachedWidgetListener) {
+    aStatus = mAttachedWidgetListener->HandleEvent(aEvent, mUseAttachedEvents);
+  } else if (mWidgetListener) {
+    aStatus = mWidgetListener->HandleEvent(aEvent, mUseAttachedEvents);
+  }
+
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::SynthesizeNativeMouseEvent(
+    LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+    MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+    nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "mouseevent");
+  EventMessage msg;
+  switch (aNativeMessage) {
+    case NativeMouseMessage::Move:
+      msg = eMouseMove;
+      break;
+    case NativeMouseMessage::ButtonDown:
+      msg = eMouseDown;
+      break;
+    case NativeMouseMessage::ButtonUp:
+      msg = eMouseUp;
+      break;
+    case NativeMouseMessage::EnterWindow:
+    case NativeMouseMessage::LeaveWindow:
+      MOZ_ASSERT_UNREACHABLE("Unsupported synthesized mouse event");
+      return NS_ERROR_UNEXPECTED;
+  }
+  WidgetMouseEvent event(true, msg, this, WidgetMouseEvent::eReal);
+  event.mRefPoint = aPoint - WidgetToScreenOffset();
+  if (msg == eMouseDown || msg == eMouseUp) {
+    event.mButton = aButton;
+  }
+  if (msg == eMouseDown) {
+    event.mClickCount = 1;
+  }
+  event.AssignEventTime(WidgetEventTime());
+  DispatchInputEvent(&event);
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::SynthesizeNativeMouseScrollEvent(
+    mozilla::LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage,
+    double aDeltaX, double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+    uint32_t aAdditionalFlags, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "mousescrollevent");
+  printf(">>> DEBUG_ME: Synth: aDeltaY=%f\n", aDeltaY);
+  // The various platforms seem to handle scrolling deltas differently,
+  // but the following seems to emulate it well enough.
+  WidgetWheelEvent event(true, eWheel, this);
+  event.mDeltaMode = MOZ_HEADLESS_SCROLL_DELTA_MODE;
+  event.mIsNoLineOrPageDelta = true;
+  event.mDeltaX = -aDeltaX * MOZ_HEADLESS_SCROLL_MULTIPLIER;
+  event.mDeltaY = -aDeltaY * MOZ_HEADLESS_SCROLL_MULTIPLIER;
+  event.mDeltaZ = -aDeltaZ * MOZ_HEADLESS_SCROLL_MULTIPLIER;
+  event.mRefPoint = aPoint - WidgetToScreenOffset();
+  event.AssignEventTime(WidgetEventTime());
+  DispatchInputEvent(&event);
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::SynthesizeNativeTouchPoint(
+    uint32_t aPointerId, TouchPointerState aPointerState,
+    LayoutDeviceIntPoint aPoint, double aPointerPressure,
+    uint32_t aPointerOrientation, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchpoint");
+
+  MOZ_ASSERT(NS_IsMainThread());
+  if (aPointerState == TOUCH_HOVER) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (!mSynthesizedTouchInput) {
+    mSynthesizedTouchInput = MakeUnique<MultiTouchInput>();
+  }
+
+  LayoutDeviceIntPoint pointInWindow = aPoint - WidgetToScreenOffset();
+  MultiTouchInput inputToDispatch = UpdateSynthesizedTouchState(
+      mSynthesizedTouchInput.get(), TimeStamp::Now(), aPointerId, aPointerState,
+      pointInWindow, aPointerPressure, aPointerOrientation);
+  DispatchTouchInput(inputToDispatch);
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::SynthesizeNativeTouchPadPinch(
+    TouchpadGesturePhase aEventPhase, float aScale, LayoutDeviceIntPoint aPoint,
+    int32_t aModifierFlags) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  PinchGestureInput::PinchGestureType pinchGestureType =
+      PinchGestureInput::PINCHGESTURE_SCALE;
+  ScreenCoord CurrentSpan;
+  ScreenCoord PreviousSpan;
+  switch (aEventPhase) {
+    case PHASE_BEGIN:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_START;
+      CurrentSpan = aScale;
+      PreviousSpan = 0.999;
+      break;
+
+    case PHASE_UPDATE:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_SCALE;
+      if (aScale == mLastPinchSpan) {
+        return NS_ERROR_INVALID_ARG;
+      }
+      CurrentSpan = aScale;
+      PreviousSpan = mLastPinchSpan;
+      break;
+
+    case PHASE_END:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_END;
+      CurrentSpan = aScale;
+      PreviousSpan = mLastPinchSpan;
+      break;
+
+    default:
+      return NS_ERROR_INVALID_ARG;
+  }
+
+  ScreenPoint touchpadPoint = ViewAs<ScreenPixel>(
+      aPoint - WidgetToScreenOffset(),
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+  // The headless widget does not support modifiers.
+  // Do not pass `aModifierFlags` because it contains native modifier values.
+  PinchGestureInput inputToDispatch(
+      pinchGestureType, PinchGestureInput::TRACKPAD, TimeStamp::Now(),
+      ExternalPoint(0, 0), touchpadPoint,
+      100.0 * ((aEventPhase == PHASE_END) ? ScreenCoord(1.f) : CurrentSpan),
+      100.0 * ((aEventPhase == PHASE_END) ? ScreenCoord(1.f) : PreviousSpan),
+      0);
+
+  if (!inputToDispatch.SetLineOrPageDeltaY(this)) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  mLastPinchSpan = aScale;
+  DispatchPinchGestureInput(inputToDispatch);
+  return NS_OK;
+}
+
+nsresult HeadlessWidget::SynthesizeNativeTouchpadPan(
+    TouchpadGesturePhase aEventPhase, LayoutDeviceIntPoint aPoint,
+    double aDeltaX, double aDeltaY, int32_t aModifierFlags,
+    nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchpadpanevent");
+
+  MOZ_ASSERT(NS_IsMainThread());
+
+  PanGestureInput::PanGestureType eventType = PanGestureInput::PANGESTURE_PAN;
+  switch (aEventPhase) {
+    case PHASE_BEGIN:
+      eventType = PanGestureInput::PANGESTURE_START;
+      break;
+    case PHASE_UPDATE:
+      eventType = PanGestureInput::PANGESTURE_PAN;
+      break;
+    case PHASE_END:
+      eventType = PanGestureInput::PANGESTURE_END;
+      break;
+    default:
+      return NS_ERROR_INVALID_ARG;
+  }
+
+  ScreenPoint touchpadPoint = ViewAs<ScreenPixel>(
+      aPoint - WidgetToScreenOffset(),
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+  PanGestureInput input(eventType, TimeStamp::Now(), touchpadPoint,
+                        ScreenPoint(float(aDeltaX), float(aDeltaY)),
+                        // Same as SynthesizeNativeTouchPadPinch case we ignore
+                        // aModifierFlags.
+                        0);
+
+  input.mSimulateMomentum =
+      Preferences::GetBool("apz.test.headless.simulate_momentum");
+
+  DispatchPanGestureInput(input);
+
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/headless/HeadlessWidget.h b/widget/headless/HeadlessWidget.h
new file mode 100644
index 0000000000..9856991ef3
--- /dev/null
+++ b/widget/headless/HeadlessWidget.h
@@ -0,0 +1,182 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef HEADLESSWIDGET_H
+#define HEADLESSWIDGET_H
+
+#include "mozilla/widget/InProcessCompositorWidget.h"
+#include "nsBaseWidget.h"
+#include "CompositorWidget.h"
+#include "mozilla/dom/WheelEventBinding.h"
+
+// The various synthesized event values are hardcoded to avoid pulling
+// in the platform specific widget code.
+#if defined(MOZ_WIDGET_GTK)
+#  define MOZ_HEADLESS_SCROLL_MULTIPLIER 3
+#  define MOZ_HEADLESS_SCROLL_DELTA_MODE \
+    mozilla::dom::WheelEvent_Binding::DOM_DELTA_LINE
+#elif defined(XP_WIN)
+#  define MOZ_HEADLESS_SCROLL_MULTIPLIER \
+    .025  // default scroll lines (3) / WHEEL_DELTA (120)
+#  define MOZ_HEADLESS_SCROLL_DELTA_MODE \
+    mozilla::dom::WheelEvent_Binding::DOM_DELTA_LINE
+#elif defined(XP_MACOSX)
+#  define MOZ_HEADLESS_SCROLL_MULTIPLIER 1
+#  define MOZ_HEADLESS_SCROLL_DELTA_MODE \
+    mozilla::dom::WheelEvent_Binding::DOM_DELTA_PIXEL
+#elif defined(ANDROID)
+#  define MOZ_HEADLESS_SCROLL_MULTIPLIER 1
+#  define MOZ_HEADLESS_SCROLL_DELTA_MODE \
+    mozilla::dom::WheelEvent_Binding::DOM_DELTA_LINE
+#else
+#  define MOZ_HEADLESS_SCROLL_MULTIPLIER -1
+#  define MOZ_HEADLESS_SCROLL_DELTA_MODE -1
+#endif
+
+namespace mozilla {
+enum class NativeKeyBindingsType : uint8_t;
+namespace widget {
+
+class HeadlessWidget : public nsBaseWidget {
+ public:
+  HeadlessWidget();
+
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(HeadlessWidget, nsBaseWidget)
+
+  void* GetNativeData(uint32_t aDataType) override {
+    // Headless widgets have no native data.
+    return nullptr;
+  }
+
+  virtual nsresult Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                          const LayoutDeviceIntRect& aRect,
+                          widget::InitData* aInitData = nullptr) override;
+  using nsBaseWidget::Create;  // for Create signature not overridden here
+  virtual already_AddRefed<nsIWidget> CreateChild(
+      const LayoutDeviceIntRect& aRect, widget::InitData* aInitData = nullptr,
+      bool aForceUseIWidgetParent = false) override;
+
+  virtual nsIWidget* GetTopLevelWidget() override;
+
+  virtual void GetCompositorWidgetInitData(
+      mozilla::widget::CompositorWidgetInitData* aInitData) override;
+
+  virtual void Destroy() override;
+  virtual void Show(bool aState) override;
+  virtual bool IsVisible() const override;
+  virtual void Move(double aX, double aY) override;
+  virtual void Resize(double aWidth, double aHeight, bool aRepaint) override;
+  virtual void Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) override;
+  virtual nsSizeMode SizeMode() override { return mSizeMode; }
+  virtual void SetSizeMode(nsSizeMode aMode) override;
+  virtual nsresult MakeFullScreen(bool aFullScreen) override;
+  virtual void Enable(bool aState) override;
+  virtual bool IsEnabled() const override;
+  virtual void SetFocus(Raise, mozilla::dom::CallerType aCallerType) override;
+  virtual void Invalidate(const LayoutDeviceIntRect& aRect) override {
+    // TODO: see if we need to do anything here.
+  }
+  virtual nsresult SetTitle(const nsAString& title) override {
+    // Headless widgets have no title, so just ignore it.
+    return NS_OK;
+  }
+  virtual nsresult SetNonClientMargins(
+      const LayoutDeviceIntMargin& margins) override {
+    // Headless widgets have no chrome margins, so just ignore the call.
+    return NS_OK;
+  }
+  virtual LayoutDeviceIntPoint WidgetToScreenOffset() override;
+  virtual void SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction) override {
+    mInputContext = aContext;
+  }
+  virtual InputContext GetInputContext() override { return mInputContext; }
+
+  virtual WindowRenderer* GetWindowRenderer() override;
+
+  void SetCompositorWidgetDelegate(CompositorWidgetDelegate* delegate) override;
+
+  [[nodiscard]] virtual nsresult AttachNativeKeyEvent(
+      WidgetKeyboardEvent& aEvent) override;
+  MOZ_CAN_RUN_SCRIPT virtual bool GetEditCommands(
+      NativeKeyBindingsType aType, const WidgetKeyboardEvent& aEvent,
+      nsTArray<CommandInt>& aCommands) override;
+
+  virtual nsresult DispatchEvent(WidgetGUIEvent* aEvent,
+                                 nsEventStatus& aStatus) override;
+
+  virtual nsresult SynthesizeNativeMouseEvent(
+      LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+      mozilla::MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+      nsIObserver* aObserver) override;
+  virtual nsresult SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
+                                             nsIObserver* aObserver) override {
+    return SynthesizeNativeMouseEvent(
+        aPoint, NativeMouseMessage::Move, mozilla::MouseButton::eNotPressed,
+        nsIWidget::Modifiers::NO_MODIFIERS, aObserver);
+  };
+
+  virtual nsresult SynthesizeNativeMouseScrollEvent(
+      LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage, double aDeltaX,
+      double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+      uint32_t aAdditionalFlags, nsIObserver* aObserver) override;
+
+  virtual nsresult SynthesizeNativeTouchPoint(uint32_t aPointerId,
+                                              TouchPointerState aPointerState,
+                                              LayoutDeviceIntPoint aPoint,
+                                              double aPointerPressure,
+                                              uint32_t aPointerOrientation,
+                                              nsIObserver* aObserver) override;
+
+  virtual nsresult SynthesizeNativeTouchPadPinch(
+      TouchpadGesturePhase aEventPhase, float aScale,
+      LayoutDeviceIntPoint aPoint, int32_t aModifierFlags) override;
+
+  virtual nsresult SynthesizeNativeTouchpadPan(TouchpadGesturePhase aEventPhase,
+                                               LayoutDeviceIntPoint aPoint,
+                                               double aDeltaX, double aDeltaY,
+                                               int32_t aModifierFlags,
+                                               nsIObserver* aObserver) override;
+
+ private:
+  ~HeadlessWidget();
+  bool mEnabled;
+  bool mVisible;
+  bool mDestroyed;
+  bool mAlwaysOnTop;
+  nsIWidget* mTopLevel;
+  HeadlessCompositorWidget* mCompositorWidget;
+  nsSizeMode mSizeMode;
+  // The size mode before entering fullscreen mode.
+  nsSizeMode mLastSizeMode;
+  // The last size mode set while the window was visible.
+  nsSizeMode mEffectiveSizeMode;
+  mozilla::ScreenCoord mLastPinchSpan;
+  InputContext mInputContext;
+  mozilla::UniquePtr<mozilla::MultiTouchInput> mSynthesizedTouchInput;
+  // In headless there is no window manager to track window bounds
+  // across size mode changes, so we must track it to emulate.
+  LayoutDeviceIntRect mRestoreBounds;
+  void ApplySizeModeSideEffects();
+  // Move while maintaining size mode.
+  void MoveInternal(int32_t aX, int32_t aY);
+  // Resize while maintaining size mode.
+  void ResizeInternal(int32_t aWidth, int32_t aHeight, bool aRepaint);
+  // Similarly, we must track the active window ourselves in order
+  // to dispatch (de)activation events properly.
+  void RaiseWindow();
+  // The top level widgets are tracked for window ordering. They are
+  // stored in order of activation where the last element is always the
+  // currently active widget.
+  static StaticAutoPtr<nsTArray<HeadlessWidget*>> sActiveWindows;
+  // Get the most recently activated widget or null if there are none.
+  static already_AddRefed<HeadlessWidget> GetActiveWindow();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/headless/HeadlessWidgetTypes.ipdlh b/widget/headless/HeadlessWidgetTypes.ipdlh
new file mode 100644
index 0000000000..ac7e0e6142
--- /dev/null
+++ b/widget/headless/HeadlessWidgetTypes.ipdlh
@@ -0,0 +1,20 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=99: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include "mozilla/GfxMessageUtils.h";
+
+using mozilla::LayoutDeviceIntSize from "Units.h";
+
+namespace mozilla {
+namespace widget {
+
+struct HeadlessCompositorWidgetInitData
+{
+  LayoutDeviceIntSize InitialClientSize;
+};
+
+} // namespace widget
+} // namespace mozilla
diff --git a/widget/headless/moz.build b/widget/headless/moz.build
new file mode 100644
index 0000000000..a46c3a10e3
--- /dev/null
+++ b/widget/headless/moz.build
@@ -0,0 +1,48 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Firefox", "Headless")
+
+DIRS += ["tests"]
+
+LOCAL_INCLUDES += [
+    "/widget",
+    "/widget/headless",
+]
+
+widget_dir = CONFIG["MOZ_WIDGET_TOOLKIT"]
+
+LOCAL_INCLUDES += [
+    "/widget/%s" % widget_dir,
+]
+
+UNIFIED_SOURCES += [
+    "HeadlessClipboard.cpp",
+    "HeadlessClipboardData.cpp",
+    "HeadlessCompositorWidget.cpp",
+    "HeadlessScreenHelper.cpp",
+    "HeadlessSound.cpp",
+    "HeadlessWidget.cpp",
+]
+
+if widget_dir == "gtk":
+    UNIFIED_SOURCES += [
+        "HeadlessLookAndFeelGTK.cpp",
+    ]
+
+if CONFIG["MOZ_WIDGET_TOOLKIT"] == "cocoa":
+    UNIFIED_SOURCES += [
+        "HeadlessKeyBindingsCocoa.mm",
+    ]
+else:
+    UNIFIED_SOURCES += [
+        "HeadlessKeyBindings.cpp",
+    ]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
diff --git a/widget/headless/tests/headless.html b/widget/headless/tests/headless.html
new file mode 100644
index 0000000000..bbde895077
--- /dev/null
+++ b/widget/headless/tests/headless.html
@@ -0,0 +1,6 @@
+<html>
+<head><meta content="text/html; charset=utf-8" http-equiv="Content-Type"></head>
+<body style="background-color: rgb(0, 255, 0); color: rgb(0, 0, 255)">
+Hi
+</body>
+</html>
diff --git a/widget/headless/tests/headless_button.html b/widget/headless/tests/headless_button.html
new file mode 100644
index 0000000000..5641066bfe
--- /dev/null
+++ b/widget/headless/tests/headless_button.html
@@ -0,0 +1,6 @@
+<html>
+<head><meta content="text/html; charset=utf-8" http-equiv="Content-Type"></head>
+<body>
+<button id="btn">button</button>
+</body>
+</html>
diff --git a/widget/headless/tests/moz.build b/widget/headless/tests/moz.build
new file mode 100644
index 0000000000..9656ad382b
--- /dev/null
+++ b/widget/headless/tests/moz.build
@@ -0,0 +1,7 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+XPCSHELL_TESTS_MANIFESTS += ["xpcshell.toml"]
diff --git a/widget/headless/tests/test_headless.js b/widget/headless/tests/test_headless.js
new file mode 100644
index 0000000000..f9183245d2
--- /dev/null
+++ b/widget/headless/tests/test_headless.js
@@ -0,0 +1,224 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+"use strict";
+const { HttpServer } = ChromeUtils.importESModule(
+  "resource://testing-common/httpd.sys.mjs"
+);
+
+do_get_profile();
+const server = new HttpServer();
+server.registerDirectory("/", do_get_cwd());
+server.start(-1);
+const ROOT = `http://localhost:${server.identity.primaryPort}`;
+const BASE = `${ROOT}/`;
+const HEADLESS_URL = Services.io.newURI(`${BASE}/headless.html`);
+const HEADLESS_BUTTON_URL = Services.io.newURI(`${BASE}/headless_button.html`);
+registerCleanupFunction(() => {
+  server.stop(() => {});
+});
+
+// Refrences to the progress listeners to keep them from being gc'ed
+// before they are called.
+const progressListeners = new Map();
+
+function loadContentWindow(windowlessBrowser, uri) {
+  return new Promise((resolve, reject) => {
+    let loadURIOptions = {
+      triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal(),
+    };
+    windowlessBrowser.loadURI(uri, loadURIOptions);
+    let docShell = windowlessBrowser.docShell;
+    let webProgress = docShell
+      .QueryInterface(Ci.nsIInterfaceRequestor)
+      .getInterface(Ci.nsIWebProgress);
+    let progressListener = {
+      onLocationChange(progress, request, location, flags) {
+        // Ignore inner-frame events
+        if (progress != webProgress) {
+          return;
+        }
+        // Ignore events that don't change the document
+        if (flags & Ci.nsIWebProgressListener.LOCATION_CHANGE_SAME_DOCUMENT) {
+          return;
+        }
+        let contentWindow = docShell.domWindow;
+        webProgress.removeProgressListener(progressListener);
+        progressListeners.delete(progressListener);
+        contentWindow.addEventListener(
+          "load",
+          event => {
+            resolve(contentWindow);
+          },
+          { once: true }
+        );
+      },
+      QueryInterface: ChromeUtils.generateQI([
+        "nsIWebProgressListener",
+        "nsISupportsWeakReference",
+      ]),
+    };
+    progressListeners.set(progressListener, progressListener);
+    webProgress.addProgressListener(
+      progressListener,
+      Ci.nsIWebProgress.NOTIFY_LOCATION
+    );
+  });
+}
+
+add_setup(function () {
+  Services.prefs.setBoolPref("security.allow_unsafe_parent_loads", true);
+});
+
+registerCleanupFunction(function () {
+  Services.prefs.clearUserPref("security.allow_unsafe_parent_loads");
+});
+
+add_task(async function test_snapshot() {
+  let windowlessBrowser = Services.appShell.createWindowlessBrowser(false);
+  let contentWindow = await loadContentWindow(windowlessBrowser, HEADLESS_URL);
+  const contentWidth = 400;
+  const contentHeight = 300;
+  // Verify dimensions.
+  contentWindow.resizeTo(contentWidth, contentHeight);
+  equal(contentWindow.innerWidth, contentWidth);
+  equal(contentWindow.innerHeight, contentHeight);
+
+  // Snapshot the test page.
+  let canvas = contentWindow.document.createElementNS(
+    "http://www.w3.org/1999/xhtml",
+    "html:canvas"
+  );
+  let context = canvas.getContext("2d");
+  let width = contentWindow.innerWidth;
+  let height = contentWindow.innerHeight;
+  canvas.width = width;
+  canvas.height = height;
+  context.drawWindow(contentWindow, 0, 0, width, height, "rgb(255, 255, 255)");
+  let imageData = context.getImageData(0, 0, width, height).data;
+  ok(
+    imageData[0] === 0 &&
+      imageData[1] === 255 &&
+      imageData[2] === 0 &&
+      imageData[3] === 255,
+    "Page is green."
+  );
+
+  // Search for a blue pixel (a quick and dirty check to see if the blue text is
+  // on the page)
+  let found = false;
+  for (let i = 0; i < imageData.length; i += 4) {
+    if (imageData[i + 2] === 255) {
+      found = true;
+      break;
+    }
+  }
+  ok(found, "Found blue text on page.");
+
+  windowlessBrowser.close();
+});
+
+add_task(async function test_snapshot_widget_layers() {
+  let windowlessBrowser = Services.appShell.createWindowlessBrowser(false);
+  // nsIWindowlessBrowser inherits from nsIWebNavigation.
+  let contentWindow = await loadContentWindow(windowlessBrowser, HEADLESS_URL);
+  const contentWidth = 1;
+  const contentHeight = 2;
+  // Verify dimensions.
+  contentWindow.resizeTo(contentWidth, contentHeight);
+  equal(contentWindow.innerWidth, contentWidth);
+  equal(contentWindow.innerHeight, contentHeight);
+
+  // Snapshot the test page.
+  let canvas = contentWindow.document.createElementNS(
+    "http://www.w3.org/1999/xhtml",
+    "html:canvas"
+  );
+  let context = canvas.getContext("2d");
+  let width = contentWindow.innerWidth;
+  let height = contentWindow.innerHeight;
+  canvas.width = width;
+  canvas.height = height;
+  context.drawWindow(
+    contentWindow,
+    0,
+    0,
+    width,
+    height,
+    "rgb(255, 255, 255)",
+    context.DRAWWINDOW_DRAW_CARET |
+      context.DRAWWINDOW_DRAW_VIEW |
+      context.DRAWWINDOW_USE_WIDGET_LAYERS
+  );
+  ok(true, "Snapshot with widget layers didn't crash.");
+
+  windowlessBrowser.close();
+});
+
+// Ensure keydown events are triggered on the windowless browser.
+add_task(async function test_keydown() {
+  let windowlessBrowser = Services.appShell.createWindowlessBrowser(false);
+  // nsIWindowlessBrowser inherits from nsIWebNavigation.
+  let contentWindow = await loadContentWindow(windowlessBrowser, HEADLESS_URL);
+
+  let keydown = new Promise(resolve => {
+    contentWindow.addEventListener(
+      "keydown",
+      () => {
+        resolve();
+      },
+      { once: true }
+    );
+  });
+
+  let tip = Cc["@mozilla.org/text-input-processor;1"].createInstance(
+    Ci.nsITextInputProcessor
+  );
+  let begun = tip.beginInputTransactionForTests(contentWindow);
+  ok(
+    begun,
+    "nsITextInputProcessor.beginInputTransactionForTests() should succeed"
+  );
+  tip.keydown(
+    new contentWindow.KeyboardEvent("", {
+      key: "a",
+      code: "KeyA",
+      keyCode: contentWindow.KeyboardEvent.DOM_VK_A,
+    })
+  );
+
+  await keydown;
+  ok(true, "Send keydown didn't crash");
+
+  windowlessBrowser.close();
+});
+
+// Test dragging the mouse on a button to ensure the creation of the drag
+// service doesn't crash in headless.
+add_task(async function test_mouse_drag() {
+  let windowlessBrowser = Services.appShell.createWindowlessBrowser(false);
+  // nsIWindowlessBrowser inherits from nsIWebNavigation.
+  let contentWindow = await loadContentWindow(
+    windowlessBrowser,
+    HEADLESS_BUTTON_URL
+  );
+  contentWindow.resizeTo(400, 400);
+
+  let target = contentWindow.document.getElementById("btn");
+  let rect = target.getBoundingClientRect();
+  let left = rect.left;
+  let top = rect.top;
+
+  let utils = contentWindow.windowUtils;
+  utils.sendMouseEvent("mousedown", left, top, 0, 1, 0, false, 0, 0);
+  utils.sendMouseEvent("mousemove", left, top, 0, 1, 0, false, 0, 0);
+  // Wait for a turn of the event loop since the synthetic mouse event
+  // that creates the drag service is processed during the refresh driver.
+  await new Promise(r => {
+    executeSoon(r);
+  });
+  utils.sendMouseEvent("mouseup", left, top, 0, 1, 0, false, 0, 0);
+
+  ok(true, "Send mouse event didn't crash");
+
+  windowlessBrowser.close();
+});
diff --git a/widget/headless/tests/test_headless_clipboard.js b/widget/headless/tests/test_headless_clipboard.js
new file mode 100644
index 0000000000..862e343001
--- /dev/null
+++ b/widget/headless/tests/test_headless_clipboard.js
@@ -0,0 +1,45 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+"use strict";
+
+function getString(clipboard) {
+  var str = "";
+
+  // Create transferable that will transfer the text.
+  var trans = Cc["@mozilla.org/widget/transferable;1"].createInstance(
+    Ci.nsITransferable
+  );
+  trans.init(null);
+  trans.addDataFlavor("text/plain");
+
+  clipboard.getData(trans, Ci.nsIClipboard.kGlobalClipboard);
+
+  try {
+    var data = {};
+    trans.getTransferData("text/plain", data);
+
+    if (data) {
+      data = data.value.QueryInterface(Ci.nsISupportsString);
+      str = data.data;
+    }
+  } catch (ex) {
+    // If the clipboard is empty getTransferData will throw.
+  }
+
+  return str;
+}
+
+add_task(async function test_clipboard() {
+  let clipboard = Services.clipboard;
+
+  // Test copy.
+  const data = "random number: " + Math.random();
+  let helper = Cc["@mozilla.org/widget/clipboardhelper;1"].getService(
+    Ci.nsIClipboardHelper
+  );
+  helper.copyString(data);
+  equal(getString(clipboard), data, "Data was successfully copied.");
+
+  clipboard.emptyClipboard(Ci.nsIClipboard.kGlobalClipboard);
+  equal(getString(clipboard), "", "Data was successfully cleared.");
+});
diff --git a/widget/headless/tests/xpcshell.toml b/widget/headless/tests/xpcshell.toml
new file mode 100644
index 0000000000..29c5fd100e
--- /dev/null
+++ b/widget/headless/tests/xpcshell.toml
@@ -0,0 +1,14 @@
+[DEFAULT]
+run-if = [
+  "os == 'linux'",
+  "os == 'win'",
+]
+headless = true
+
+["test_headless.js"]
+support-files = [
+  "headless.html",
+  "headless_button.html",
+]
+
+["test_headless_clipboard.js"]
diff --git a/widget/moz.build b/widget/moz.build
new file mode 100644
index 0000000000..54a231c67d
--- /dev/null
+++ b/widget/moz.build
@@ -0,0 +1,396 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "Widget")
+
+with Files("crashtests/*1128214*"):
+    BUG_COMPONENT = ("Core", "Layout")
+
+with Files("crashtests/*303901*"):
+    BUG_COMPONENT = ("Core", "Graphics")
+
+with Files("crashtests/*380359*"):
+    BUG_COMPONENT = ("Core", "Widget")
+
+with Files("reftests/**"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("reftests/*fallback*"):
+    BUG_COMPONENT = ("Core", "Layout: Form Controls")
+
+with Files("*CompositorWidget*"):
+    BUG_COMPONENT = ("Core", "Graphics")
+
+with Files("*ContentCache*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*ContentData*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*Events.h"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*FontRange*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*Gfx*"):
+    BUG_COMPONENT = ("Core", "Graphics")
+
+with Files("*IMEData*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*TextEventDispatcher*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*NativeKeyBindings*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+toolkit = CONFIG["MOZ_WIDGET_TOOLKIT"]
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
+
+if toolkit in ("android", "cocoa", "gtk", "uikit", "windows"):
+    DIRS += [toolkit]
+
+if toolkit == "cocoa":
+    XPIDL_SOURCES += [
+        "nsIMacDockSupport.idl",
+        "nsIMacFinderProgress.idl",
+        "nsIMacSharingService.idl",
+        "nsIMacUserActivityUpdater.idl",
+        "nsIMacWebAppUtils.idl",
+        "nsIStandaloneNativeMenu.idl",
+        "nsITaskbarProgress.idl",
+        "nsITouchBarHelper.idl",
+        "nsITouchBarInput.idl",
+        "nsITouchBarUpdater.idl",
+    ]
+elif toolkit == "gtk":
+    XPIDL_SOURCES += [
+        "nsIApplicationChooser.idl",
+        "nsIGtkTaskbarProgress.idl",
+        "nsITaskbarProgress.idl",
+    ]
+elif toolkit == "windows":
+    XPIDL_SOURCES += [
+        "nsIJumpListBuilder.idl",
+        "nsILegacyJumpListBuilder.idl",
+        "nsILegacyJumpListItem.idl",
+        "nsIPrintSettingsWin.idl",
+        "nsITaskbarOverlayIconController.idl",
+        "nsITaskbarPreview.idl",
+        "nsITaskbarPreviewButton.idl",
+        "nsITaskbarPreviewController.idl",
+        "nsITaskbarProgress.idl",
+        "nsITaskbarTabPreview.idl",
+        "nsITaskbarWindowPreview.idl",
+        "nsIWindowsUIUtils.idl",
+        "nsIWinTaskbar.idl",
+    ]
+
+if CONFIG["NS_PRINTING"]:
+    # Needs to go before the XPIDL_MODULE line.
+    XPIDL_SOURCES += [
+        "nsIPrintDialogService.idl",
+    ]
+
+TEST_DIRS += ["tests", "tests/gtest"]
+
+DIRS += ["headless"]
+
+# Don't build the DSO under the 'build' directory as windows does.
+#
+# The DSOs get built in the toolkit dir itself.  Do this so that
+# multiple implementations of widget can be built on the same
+# source tree.
+#
+
+XPIDL_SOURCES += [
+    "nsIAppShell.idl",
+    "nsIBaseWindow.idl",
+    "nsIBidiKeyboard.idl",
+    "nsIClipboard.idl",
+    "nsIClipboardHelper.idl",
+    "nsIClipboardOwner.idl",
+    "nsIColorPicker.idl",
+    "nsIDisplayInfo.idl",
+    "nsIDragService.idl",
+    "nsIDragSession.idl",
+    "nsIFilePicker.idl",
+    "nsIFormatConverter.idl",
+    "nsIGfxInfo.idl",
+    "nsIGfxInfoDebug.idl",
+    "nsIPaper.idl",
+    "nsIPaperMargin.idl",
+    "nsIPrinter.idl",
+    "nsIPrinterList.idl",
+    "nsIPrintSettings.idl",
+    "nsIPrintSettingsService.idl",
+    "nsIScreen.idl",
+    "nsIScreenManager.idl",
+    "nsISharePicker.idl",
+    "nsISound.idl",
+    "nsISystemStatusBar.idl",
+    "nsITransferable.idl",
+    "nsIUserIdleService.idl",
+    "nsIUserIdleServiceInternal.idl",
+]
+
+XPIDL_MODULE = "widget"
+
+EXPORTS += [
+    "GfxDriverInfo.h",
+    "GfxInfoBase.h",
+    "GfxInfoCollector.h",
+    "InputData.h",
+    "nsBaseAppShell.h",
+    "nsBaseClipboard.h",
+    "nsBaseDragService.h",
+    "nsBaseFilePicker.h",
+    "nsBaseWidget.h",
+    "nsIDeviceContextSpec.h",
+    "nsIRollupListener.h",
+    "nsIWidget.h",
+    "nsIWidgetListener.h",
+    "nsPaper.h",
+    "nsPrinterListBase.h",
+    "nsUserIdleService.h",
+    "nsWidgetsCID.h",
+    "PuppetWidget.h",
+]
+
+EXPORTS.mozilla += [
+    "BasicEvents.h",
+    "ClipboardReadRequestChild.h",
+    "ClipboardReadRequestParent.h",
+    "ClipboardWriteRequestChild.h",
+    "ClipboardWriteRequestParent.h",
+    "ColorScheme.h",
+    "CommandList.h",
+    "ContentCache.h",
+    "ContentData.h",
+    "ContentEvents.h",
+    "DimensionRequest.h",
+    "EventClassList.h",
+    "EventForwards.h",
+    "EventMessageList.h",
+    "FontRange.h",
+    "LookAndFeel.h",
+    "MiscEvents.h",
+    "MouseEvents.h",
+    "NativeKeyBindingsType.h",
+    "SwipeTracker.h",
+    "TextEventDispatcher.h",
+    "TextEventDispatcherListener.h",
+    "TextEvents.h",
+    "TextRange.h",
+    "TouchEvents.h",
+    "VsyncDispatcher.h",
+    "WidgetUtils.h",
+    "WindowButtonType.h",
+]
+
+EXPORTS.mozilla.widget += [
+    "CompositorWidget.h",
+    "IconLoader.h",
+    "IMEData.h",
+    "InitData.h",
+    "InProcessCompositorWidget.h",
+    "MediaKeysEventSourceFactory.h",
+    "NativeMenu.h",
+    "NativeMenuSupport.h",
+    "nsAutoRollup.h",
+    "nsXPLookAndFeel.h",
+    "PuppetBidiKeyboard.h",
+    "RemoteLookAndFeel.h",
+    "Screen.h",
+    "ScreenManager.h",
+    "TextRecognition.h",
+    "ThemeChangeKind.h",
+    "WidgetMessageUtils.h",
+    "WindowOcclusionState.h",
+]
+
+UNIFIED_SOURCES += [
+    "ClipboardReadRequestParent.cpp",
+    "ClipboardWriteRequestChild.cpp",
+    "ClipboardWriteRequestParent.cpp",
+    "CompositorWidget.cpp",
+    "ContentCache.cpp",
+    "ContentData.cpp",
+    "DimensionRequest.cpp",
+    "GfxDriverInfo.cpp",
+    "GfxInfoBase.cpp",
+    "GfxInfoCollector.cpp",
+    "IconLoader.cpp",
+    "IMEData.cpp",
+    "InProcessCompositorWidget.cpp",
+    "InputData.cpp",
+    "nsAutoRollup.cpp",
+    "nsBaseAppShell.cpp",
+    "nsBaseClipboard.cpp",
+    "nsClipboardHelper.cpp",
+    "nsClipboardProxy.cpp",
+    "nsColorPickerProxy.cpp",
+    "nsDragServiceProxy.cpp",
+    "nsFilePickerProxy.cpp",
+    "nsHTMLFormatConverter.cpp",
+    "nsIBaseWindow.cpp",
+    "nsIDeviceContextSpec.cpp",
+    "nsIWidgetListener.cpp",
+    "nsPrimitiveHelpers.cpp",
+    "nsPrintSettingsImpl.cpp",
+    "nsTransferable.cpp",
+    "nsUserIdleService.cpp",
+    "nsXPLookAndFeel.cpp",
+    "PuppetBidiKeyboard.cpp",
+    "PuppetWidget.cpp",
+    "RemoteLookAndFeel.cpp",
+    "Screen.cpp",
+    "ScrollbarDrawing.cpp",
+    "ScrollbarDrawingAndroid.cpp",
+    "ScrollbarDrawingCocoa.cpp",
+    "ScrollbarDrawingGTK.cpp",
+    "ScrollbarDrawingWin.cpp",
+    "ScrollbarDrawingWin11.cpp",
+    "SharedWidgetUtils.cpp",
+    "SwipeTracker.cpp",
+    "TextEventDispatcher.cpp",
+    "TextRecognition.cpp",
+    "Theme.cpp",
+    "ThemeCocoa.cpp",
+    "ThemeColors.cpp",
+    "ThemeDrawing.cpp",
+    "TouchResampler.cpp",
+    "VsyncDispatcher.cpp",
+    "WidgetEventImpl.cpp",
+    "WidgetUtils.cpp",
+]
+
+if CONFIG["OS_ARCH"] == "Linux":
+    EXPORTS.mozilla.widget += ["LSBUtils.h"]
+    SOURCES += ["LSBUtils.cpp"]
+
+if CONFIG["NS_PRINTING"]:
+    EXPORTS += [
+        "nsDeviceContextSpecProxy.h",
+        "nsPrintSettingsService.h",
+    ]
+    UNIFIED_SOURCES += [
+        "nsDeviceContextSpecProxy.cpp",
+        "nsPaper.cpp",
+        "nsPaperMargin.cpp",
+        "nsPrinterBase.cpp",
+        "nsPrinterListBase.cpp",
+        "nsPrintSettingsService.cpp",
+    ]
+
+    if toolkit in ("cocoa", "gtk"):
+        UNIFIED_SOURCES += [
+            "nsCUPSShim.cpp",
+            "nsPrinterCUPS.cpp",
+            "nsPrinterListCUPS.cpp",
+        ]
+
+# nsBaseWidget.cpp needs to be built separately because of name clashes in the OS X headers
+# nsBaseDragService.cpp moved out of UNIFIED to fix xgill crash (bug 1259850) after moving widget/ContentHelper -> apz/util/TouchActionHelper
+SOURCES += [
+    "nsBaseDragService.cpp",
+    "nsBaseWidget.cpp",
+    "ScreenManager.cpp",
+]
+
+if CONFIG["MOZ_INSTRUMENT_EVENT_LOOP"]:
+    EXPORTS.mozilla += [
+        "WidgetTraceEvent.h",
+    ]
+
+EXPORTS.ipc = [
+    "nsGUIEventIPC.h",
+]
+
+if CONFIG["MOZ_X11"] or CONFIG["MOZ_WAYLAND"]:
+    DIRS += ["x11"]
+
+if toolkit in {"gtk", "cocoa", "windows", "android", "uikit"}:
+    UNIFIED_SOURCES += [
+        "nsBaseFilePicker.cpp",
+    ]
+
+if toolkit in ("gtk", "windows", "cocoa", "android"):
+    UNIFIED_SOURCES += [
+        "nsNativeTheme.cpp",
+    ]
+
+DEFINES["MOZ_CROSS_PROCESS_IME"] = True
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+LOCAL_INCLUDES += [
+    "/dom/base",
+    "/dom/ipc",
+    "/gfx/2d",
+    "/layout/base",
+    "/layout/forms",
+    "/layout/generic",
+    "/layout/painting",
+    "/layout/xul",
+    "/layout/xul/tree/",
+    "/view",
+    "/widget",
+    "/widget/headless",
+]
+
+# We use the CUPS headers on Cocoa and GTK, but on GTK we don't depend on there being system headers.
+if toolkit == "gtk":
+    LOCAL_INCLUDES += ["/third_party/cups/include"]
+
+if toolkit == "windows":
+    IPDL_SOURCES = [
+        "headless/HeadlessWidgetTypes.ipdlh",
+        "windows/PCompositorWidget.ipdl",
+        "windows/PlatformWidgetTypes.ipdlh",
+    ]
+elif CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
+    IPDL_SOURCES = [
+        "gtk/PCompositorWidget.ipdl",
+        "gtk/PlatformWidgetTypes.ipdlh",
+        "headless/HeadlessWidgetTypes.ipdlh",
+    ]
+elif toolkit == "android":
+    IPDL_SOURCES = [
+        "android/PCompositorWidget.ipdl",
+        "android/PlatformWidgetTypes.ipdlh",
+        "headless/HeadlessWidgetTypes.ipdlh",
+    ]
+else:
+    IPDL_SOURCES = [
+        "generic/PCompositorWidget.ipdl",
+        "generic/PlatformWidgetTypes.ipdlh",
+        "headless/HeadlessWidgetTypes.ipdlh",
+    ]
+
+IPDL_SOURCES += [
+    "LookAndFeelTypes.ipdlh",
+    "PClipboardReadRequest.ipdl",
+    "PClipboardWriteRequest.ipdl",
+]
+
+LOCAL_INCLUDES += [
+    "/widget/%s" % toolkit,
+]
+FINAL_LIBRARY = "xul"
+
+if CONFIG["MOZ_ENABLE_D3D10_LAYER"]:
+    DEFINES["MOZ_ENABLE_D3D10_LAYER"] = True
+
+if CONFIG["MOZ_WIDGET_TOOLKIT"] == "gtk":
+    CXXFLAGS += CONFIG["MOZ_GTK3_CFLAGS"]
+if CONFIG["MOZ_WAYLAND"]:
+    CXXFLAGS += CONFIG["MOZ_WAYLAND_CFLAGS"]
diff --git a/widget/nsAppShellSingleton.h b/widget/nsAppShellSingleton.h
new file mode 100644
index 0000000000..cd554951c6
--- /dev/null
+++ b/widget/nsAppShellSingleton.h
@@ -0,0 +1,60 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsAppShellSingleton_h__
+#define nsAppShellSingleton_h__
+
+/**
+ * This file is designed to be included into the file that provides the
+ * XPCOM module implementation for a particular widget toolkit.
+ *
+ * The following functions are defined:
+ *   nsAppShellInit
+ *   nsAppShellShutdown
+ *   nsAppShellConstructor
+ *
+ * The nsAppShellInit function is designed to be used as a module constructor.
+ * If you already have a module constructor, then call nsAppShellInit from your
+ * module constructor.
+ *
+ * The nsAppShellShutdown function is designed to be used as a module
+ * destructor.  If you already have a module destructor, then call
+ * nsAppShellShutdown from your module destructor.
+ *
+ * The nsAppShellConstructor function is designed to be used as a factory
+ * method for the nsAppShell class.
+ */
+
+#include "nsXULAppAPI.h"
+
+static nsIAppShell* sAppShell;
+
+static nsresult nsAppShellInit() {
+  NS_ASSERTION(!sAppShell, "already initialized");
+
+  sAppShell = new nsAppShell();
+  if (!sAppShell) return NS_ERROR_OUT_OF_MEMORY;
+  NS_ADDREF(sAppShell);
+
+  nsresult rv = static_cast<nsAppShell*>(sAppShell)->Init();
+  // If we somehow failed to initialize the appshell, it's extremely likely
+  // that we are sufficiently hosed that continuing on is just going to lead
+  // to bad things later.  By crashing early here, the crash report will
+  // potentially contain a little more insight into what's going wrong than
+  // if we waited for a crash further down the line.  See also bug 1545381.
+  MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
+
+  return NS_OK;
+}
+
+static void nsAppShellShutdown() { NS_RELEASE(sAppShell); }
+
+nsresult nsAppShellConstructor(const nsIID& iid, void** result) {
+  NS_ENSURE_TRUE(sAppShell, NS_ERROR_NOT_INITIALIZED);
+
+  return sAppShell->QueryInterface(iid, result);
+}
+
+#endif  // nsAppShellSingleton_h__
diff --git a/widget/nsAutoRollup.cpp b/widget/nsAutoRollup.cpp
new file mode 100644
index 0000000000..9a043576df
--- /dev/null
+++ b/widget/nsAutoRollup.cpp
@@ -0,0 +1,50 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/widget/nsAutoRollup.h"
+
+namespace mozilla {
+namespace widget {
+
+/*static*/
+uint32_t nsAutoRollup::sCount = 0;
+/*static*/
+StaticRefPtr<nsIContent> nsAutoRollup::sLastRollup;
+
+nsAutoRollup::nsAutoRollup() {
+  // remember if sLastRollup was null, and only clear it upon destruction
+  // if so. This prevents recursive usage of nsAutoRollup from clearing
+  // sLastRollup when it shouldn't.
+  mWasClear = !sLastRollup;
+  sCount++;
+}
+
+nsAutoRollup::nsAutoRollup(nsIContent* aRollup) {
+  MOZ_ASSERT(!sLastRollup);
+  mWasClear = true;
+  sCount++;
+  SetLastRollup(aRollup);
+}
+
+nsAutoRollup::~nsAutoRollup() {
+  if (sLastRollup && mWasClear) {
+    sLastRollup = nullptr;
+  }
+  sCount--;
+}
+
+/*static*/
+void nsAutoRollup::SetLastRollup(nsIContent* aLastRollup) {
+  // There must be at least one nsAutoRollup on the stack.
+  MOZ_ASSERT(sCount);
+
+  sLastRollup = aLastRollup;
+}
+
+/*static*/
+nsIContent* nsAutoRollup::GetLastRollup() { return sLastRollup.get(); }
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/nsAutoRollup.h b/widget/nsAutoRollup.h
new file mode 100644
index 0000000000..f6f3685887
--- /dev/null
+++ b/widget/nsAutoRollup.h
@@ -0,0 +1,54 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef nsAutoRollup_h__
+#define nsAutoRollup_h__
+
+#include "mozilla/Attributes.h"  // for MOZ_RAII
+#include "mozilla/StaticPtr.h"   // for StaticRefPtr
+#include "nsIContent.h"
+
+namespace mozilla {
+namespace widget {
+
+// A situation can occur when a mouse event occurs over a menu label while the
+// menu popup is already open. The expected behaviour is to close the popup.
+// This happens by calling nsIRollupListener::Rollup before the mouse event is
+// processed. However, in cases where the mouse event is not consumed, this
+// event will then get targeted at the menu label causing the menu to open
+// again. To prevent this, we store in sLastRollup a reference to the popup
+// that was closed during the Rollup call, and prevent this popup from
+// reopening while processing the mouse event.
+// sLastRollup can only be set while an nsAutoRollup is in scope;
+// when it goes out of scope sLastRollup is cleared automatically.
+// As sLastRollup is static, it can be retrieved by calling
+// nsAutoRollup::GetLastRollup.
+class MOZ_RAII nsAutoRollup {
+ public:
+  nsAutoRollup();
+  ~nsAutoRollup();
+
+  // Convenience constructor that creates a nsAutoRollup and also sets
+  // the last rollup.
+  explicit nsAutoRollup(nsIContent* aRollup);
+
+  static void SetLastRollup(nsIContent* aLastRollup);
+  // Return the popup that was last rolled up, or null if there isn't one.
+  static nsIContent* GetLastRollup();
+
+ private:
+  // Whether sLastRollup was clear when this nsAutoRollup
+  // was created.
+  bool mWasClear;
+
+  // The number of nsAutoRollup instances active.
+  static uint32_t sCount;
+  // The last rolled up popup.
+  static StaticRefPtr<nsIContent> sLastRollup;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // nsAutoRollup_h__
diff --git a/widget/nsBaseAppShell.cpp b/widget/nsBaseAppShell.cpp
new file mode 100644
index 0000000000..632f38478c
--- /dev/null
+++ b/widget/nsBaseAppShell.cpp
@@ -0,0 +1,313 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "base/message_loop.h"
+
+#include "nsBaseAppShell.h"
+#include "nsExceptionHandler.h"
+#include "nsJSUtils.h"
+#include "nsThreadUtils.h"
+#include "nsIAppShell.h"
+#include "nsIObserverService.h"
+#include "nsServiceManagerUtils.h"
+#include "mozilla/Services.h"
+#include "nsXULAppAPI.h"
+
+// When processing the next thread event, the appshell may process native
+// events (if not in performance mode), which can result in suppressing the
+// next thread event for at most this many ticks:
+#define THREAD_EVENT_STARVATION_LIMIT PR_MillisecondsToInterval(10)
+
+NS_IMPL_ISUPPORTS(nsBaseAppShell, nsIAppShell, nsIThreadObserver, nsIObserver)
+
+nsBaseAppShell::nsBaseAppShell()
+    : mSuspendNativeCount(0),
+      mEventloopNestingLevel(0),
+      mBlockedWait(nullptr),
+      mNativeEventPending(false),
+      mGeckoTaskBurstStartTime(0),
+      mLastNativeEventTime(0),
+      mEventloopNestingState(eEventloopNone),
+      mRunning(false),
+      mExiting(false),
+      mBlockNativeEvent(false),
+      mProcessedGeckoEvents(false) {}
+
+nsBaseAppShell::~nsBaseAppShell() = default;
+
+nsresult nsBaseAppShell::Init() {
+  // Configure ourselves as an observer for the current thread:
+
+  if (XRE_UseNativeEventProcessing()) {
+    nsCOMPtr<nsIThreadInternal> threadInt =
+        do_QueryInterface(NS_GetCurrentThread());
+    NS_ENSURE_STATE(threadInt);
+
+    threadInt->SetObserver(this);
+  }
+
+  nsCOMPtr<nsIObserverService> obsSvc = mozilla::services::GetObserverService();
+  if (obsSvc) obsSvc->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
+  return NS_OK;
+}
+
+// Called by nsAppShell's native event callback
+void nsBaseAppShell::NativeEventCallback() {
+  if (!mNativeEventPending.exchange(false)) return;
+
+  // If DoProcessNextNativeEvent is on the stack, then we assume that we can
+  // just unwind and let nsThread::ProcessNextEvent process the next event.
+  // However, if we are called from a nested native event loop (maybe via some
+  // plug-in or library function), then go ahead and process Gecko events now.
+  if (mEventloopNestingState == eEventloopXPCOM) {
+    mEventloopNestingState = eEventloopOther;
+    // XXX there is a tiny risk we will never get a new NativeEventCallback,
+    // XXX see discussion in bug 389931.
+    return;
+  }
+
+  // nsBaseAppShell::Run is not being used to pump events, so this may be
+  // our only opportunity to process pending gecko events.
+
+  nsIThread* thread = NS_GetCurrentThread();
+  bool prevBlockNativeEvent = mBlockNativeEvent;
+  if (mEventloopNestingState == eEventloopOther) {
+    if (!NS_HasPendingEvents(thread)) return;
+    // We're in a nested native event loop and have some gecko events to
+    // process.  While doing that we block processing native events from the
+    // appshell - instead, we want to get back to the nested native event
+    // loop ASAP (bug 420148).
+    mBlockNativeEvent = true;
+  }
+
+  IncrementEventloopNestingLevel();
+  EventloopNestingState prevVal = mEventloopNestingState;
+  NS_ProcessPendingEvents(thread, THREAD_EVENT_STARVATION_LIMIT);
+  mProcessedGeckoEvents = true;
+  mEventloopNestingState = prevVal;
+  mBlockNativeEvent = prevBlockNativeEvent;
+
+  // Continue processing pending events later (we don't want to starve the
+  // embedders event loop).
+  if (NS_HasPendingEvents(thread)) DoProcessMoreGeckoEvents();
+
+  DecrementEventloopNestingLevel();
+}
+
+void nsBaseAppShell::OnSystemTimezoneChange() {
+  nsJSUtils::ResetTimeZone();
+
+  nsCOMPtr<nsIObserverService> obsSvc = mozilla::services::GetObserverService();
+  if (obsSvc) {
+    // Timezone changed notification
+    obsSvc->NotifyObservers(nullptr, DEFAULT_TIMEZONE_CHANGED_OBSERVER_TOPIC,
+                            nullptr);
+  }
+}
+
+// Note, this is currently overidden on windows, see comments in nsAppShell for
+// details.
+void nsBaseAppShell::DoProcessMoreGeckoEvents() { OnDispatchedEvent(); }
+
+// Main thread via OnProcessNextEvent below
+bool nsBaseAppShell::DoProcessNextNativeEvent(bool mayWait) {
+  // The next native event to be processed may trigger our NativeEventCallback,
+  // in which case we do not want it to process any thread events since we'll
+  // do that when this function returns.
+  //
+  // If the next native event is not our NativeEventCallback, then we may end
+  // up recursing into this function.
+  //
+  // However, if the next native event is not our NativeEventCallback, but it
+  // results in another native event loop, then our NativeEventCallback could
+  // fire and it will see mEventloopNestingState as eEventloopOther.
+  //
+  EventloopNestingState prevVal = mEventloopNestingState;
+  mEventloopNestingState = eEventloopXPCOM;
+
+  IncrementEventloopNestingLevel();
+  bool result = ProcessNextNativeEvent(mayWait);
+  DecrementEventloopNestingLevel();
+
+  mEventloopNestingState = prevVal;
+  return result;
+}
+
+//-------------------------------------------------------------------------
+// nsIAppShell methods:
+
+NS_IMETHODIMP
+nsBaseAppShell::Run(void) {
+  NS_ENSURE_STATE(!mRunning);  // should not call Run twice
+  mRunning = true;
+
+  nsIThread* thread = NS_GetCurrentThread();
+
+  MessageLoop::current()->Run();
+
+  NS_ProcessPendingEvents(thread);
+
+  mRunning = false;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::Exit(void) {
+  if (mRunning && !mExiting) {
+    MessageLoop::current()->Quit();
+  }
+  mExiting = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::GeckoTaskBurst() {
+  if (mGeckoTaskBurstStartTime == 0) {
+    mGeckoTaskBurstStartTime = PR_IntervalNow();
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::SuspendNative() {
+  ++mSuspendNativeCount;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::ResumeNative() {
+  --mSuspendNativeCount;
+  NS_ASSERTION(mSuspendNativeCount >= 0,
+               "Unbalanced call to nsBaseAppShell::ResumeNative!");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::GetEventloopNestingLevel(uint32_t* aNestingLevelResult) {
+  NS_ENSURE_ARG_POINTER(aNestingLevelResult);
+
+  *aNestingLevelResult = mEventloopNestingLevel;
+
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+// nsIThreadObserver methods:
+
+// Called from any thread
+NS_IMETHODIMP
+nsBaseAppShell::OnDispatchedEvent() {
+  if (mBlockNativeEvent) return NS_OK;
+
+  if (mNativeEventPending.exchange(true)) return NS_OK;
+
+  // Returns on the main thread in NativeEventCallback above
+  ScheduleNativeEventCallback();
+  return NS_OK;
+}
+
+// Called from the main thread
+NS_IMETHODIMP
+nsBaseAppShell::OnProcessNextEvent(nsIThreadInternal* thr, bool mayWait) {
+  if (mBlockNativeEvent) {
+    if (!mayWait) return NS_OK;
+    // Hmm, we're in a nested native event loop and would like to get
+    // back to it ASAP, but it seems a gecko event has caused us to
+    // spin up a nested XPCOM event loop (eg. modal window), so we
+    // really must start processing native events here again.
+    mBlockNativeEvent = false;
+    if (NS_HasPendingEvents(thr))
+      OnDispatchedEvent();  // in case we blocked it earlier
+  }
+
+  PRIntervalTime start = PR_IntervalNow();
+  PRIntervalTime limit = THREAD_EVENT_STARVATION_LIMIT;
+
+  // Unblock outer nested wait loop (below).
+  if (mBlockedWait) *mBlockedWait = false;
+
+  bool* oldBlockedWait = mBlockedWait;
+  mBlockedWait = &mayWait;
+
+  // When mayWait is true, we need to make sure that there is an event in the
+  // thread's event queue before we return.  Otherwise, the thread will block
+  // on its event queue waiting for an event.
+  bool needEvent = mayWait;
+  // Reset prior to invoking DoProcessNextNativeEvent which might cause
+  // NativeEventCallback to process gecko events.
+  mProcessedGeckoEvents = false;
+
+  // Content processes always priorize gecko events.
+  if (!XRE_IsContentProcess() && (start > (mGeckoTaskBurstStartTime + limit))) {
+    mGeckoTaskBurstStartTime = 0;
+    // Favor pending native events
+    PRIntervalTime now = start;
+    bool keepGoing;
+    do {
+      mLastNativeEventTime = now;
+      keepGoing = DoProcessNextNativeEvent(false);
+    } while (keepGoing && ((now = PR_IntervalNow()) - start) < limit);
+  } else {
+    // Avoid starving native events completely when in performance mode
+    if (start - mLastNativeEventTime > limit) {
+      mLastNativeEventTime = start;
+      DoProcessNextNativeEvent(false);
+    }
+  }
+
+  while (!NS_HasPendingEvents(thr) && !mProcessedGeckoEvents) {
+    // If we have been asked to exit from Run, then we should not wait for
+    // events to process.  Note that an inner nested event loop causes
+    // 'mayWait' to become false too, through 'mBlockedWait'.
+    if (mExiting) mayWait = false;
+
+    mLastNativeEventTime = PR_IntervalNow();
+    if (!DoProcessNextNativeEvent(mayWait) || !mayWait) break;
+  }
+
+  mBlockedWait = oldBlockedWait;
+
+  // Make sure that the thread event queue does not block on its monitor, as
+  // it normally would do if it did not have any pending events.  To avoid
+  // that, we simply insert a dummy event into its queue during shutdown.
+  if (needEvent && !mExiting && !NS_HasPendingEvents(thr)) {
+    DispatchDummyEvent(thr);
+  }
+
+  return NS_OK;
+}
+
+bool nsBaseAppShell::DispatchDummyEvent(nsIThread* aTarget) {
+  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
+
+  if (!mDummyEvent) mDummyEvent = new mozilla::Runnable("DummyEvent");
+
+  return NS_SUCCEEDED(aTarget->Dispatch(mDummyEvent, NS_DISPATCH_NORMAL));
+}
+
+void nsBaseAppShell::IncrementEventloopNestingLevel() {
+  ++mEventloopNestingLevel;
+  CrashReporter::SetEventloopNestingLevel(mEventloopNestingLevel);
+}
+
+void nsBaseAppShell::DecrementEventloopNestingLevel() {
+  --mEventloopNestingLevel;
+  CrashReporter::SetEventloopNestingLevel(mEventloopNestingLevel);
+}
+
+// Called from the main thread
+NS_IMETHODIMP
+nsBaseAppShell::AfterProcessNextEvent(nsIThreadInternal* thr,
+                                      bool eventWasProcessed) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::Observe(nsISupports* subject, const char* topic,
+                        const char16_t* data) {
+  NS_ASSERTION(!strcmp(topic, NS_XPCOM_SHUTDOWN_OBSERVER_ID), "oops");
+  Exit();
+  return NS_OK;
+}
diff --git a/widget/nsBaseAppShell.h b/widget/nsBaseAppShell.h
new file mode 100644
index 0000000000..fabc0e188a
--- /dev/null
+++ b/widget/nsBaseAppShell.h
@@ -0,0 +1,140 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsBaseAppShell_h__
+#define nsBaseAppShell_h__
+
+#include "mozilla/Atomics.h"
+#include "nsIAppShell.h"
+#include "nsIThreadInternal.h"
+#include "nsIObserver.h"
+#include "nsIRunnable.h"
+#include "nsCOMPtr.h"
+#include "nsTArray.h"
+#include "prinrval.h"
+
+/**
+ * A singleton that manages the UI thread's event queue.  Subclass this class
+ * to enable platform-specific event queue support.
+ */
+class nsBaseAppShell : public nsIAppShell,
+                       public nsIThreadObserver,
+                       public nsIObserver {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIAPPSHELL
+
+  NS_DECL_NSITHREADOBSERVER
+  NS_DECL_NSIOBSERVER
+
+  nsBaseAppShell();
+
+  /**
+   * Called by subclasses. Reset the internal timezone when the user's system
+   * timezone changes.
+   */
+  static void OnSystemTimezoneChange();
+
+ protected:
+  virtual ~nsBaseAppShell();
+
+  /**
+   * This method is called by subclasses when the app shell singleton is
+   * instantiated.
+   */
+  nsresult Init();
+
+  /**
+   * Called by subclasses from a native event. See ScheduleNativeEventCallback.
+   */
+  void NativeEventCallback();
+
+  /**
+   * Make a decision as to whether or not NativeEventCallback will
+   * trigger gecko event processing when there are pending gecko
+   * events.
+   */
+  virtual void DoProcessMoreGeckoEvents();
+
+  /**
+   * Implemented by subclasses.  Invoke NativeEventCallback from a native
+   * event.  This method may be called on any thread.
+   */
+  virtual void ScheduleNativeEventCallback() = 0;
+
+  /**
+   * Implemented by subclasses.  Process the next native event.  Only wait for
+   * the next native event if mayWait is true.  This method is only called on
+   * the main application thread.
+   *
+   * @param mayWait
+   *   If "true", then this method may wait if necessary for the next available
+   *   native event.  DispatchNativeEvent may be called to unblock a call to
+   *   ProcessNextNativeEvent that is waiting.
+   * @return
+   *   This method returns "true" if a native event was processed.
+   */
+  virtual bool ProcessNextNativeEvent(bool mayWait) = 0;
+
+  int32_t mSuspendNativeCount;
+  uint32_t mEventloopNestingLevel;
+
+ private:
+  bool DoProcessNextNativeEvent(bool mayWait);
+
+  bool DispatchDummyEvent(nsIThread* target);
+
+  void IncrementEventloopNestingLevel();
+  void DecrementEventloopNestingLevel();
+
+  nsCOMPtr<nsIRunnable> mDummyEvent;
+  /**
+   * mBlockedWait points back to a slot that controls the wait loop in
+   * an outer OnProcessNextEvent invocation.  Nested calls always set
+   * it to false to unblock an outer loop, since all events may
+   * have been consumed by the inner event loop(s).
+   */
+  bool* mBlockedWait;
+  mozilla::Atomic<bool> mNativeEventPending;
+  PRIntervalTime mGeckoTaskBurstStartTime;
+  PRIntervalTime mLastNativeEventTime;
+  enum EventloopNestingState {
+    eEventloopNone,   // top level thread execution
+    eEventloopXPCOM,  // innermost native event loop is ProcessNextNativeEvent
+    eEventloopOther   // innermost native event loop is a native library/plugin
+                      // etc
+  };
+  EventloopNestingState mEventloopNestingState;
+  bool mRunning;
+  bool mExiting;
+  /**
+   * mBlockNativeEvent blocks the appshell from processing native events.
+   * It is set to true while a nested native event loop (eEventloopOther)
+   * is processing gecko events in NativeEventCallback(), thus queuing up
+   * native events until we return to that loop (bug 420148).
+   * We force mBlockNativeEvent to false in case handling one of the gecko
+   * events spins up a nested XPCOM event loop (eg. modal window) which would
+   * otherwise lead to a "deadlock" where native events aren't processed at all.
+   */
+  bool mBlockNativeEvent;
+  /**
+   * Tracks whether we have processed any gecko events in NativeEventCallback so
+   * that we can avoid erroneously entering a blocking loop waiting for gecko
+   * events to show up during OnProcessNextEvent.  This is required because on
+   * OS X ProcessGeckoEvents may be invoked inside the context of
+   * ProcessNextNativeEvent and may result in NativeEventCallback being invoked
+   * and in turn invoking NS_ProcessPendingEvents.  Because
+   * ProcessNextNativeEvent may be invoked prior to the NS_HasPendingEvents
+   * waiting loop, this is the only way to make the loop aware that events may
+   * have been processed.
+   *
+   * This variable is set to false in OnProcessNextEvent prior to the first
+   * call to DoProcessNextNativeEvent.  It is set to true by
+   * NativeEventCallback after calling NS_ProcessPendingEvents.
+   */
+  bool mProcessedGeckoEvents;
+};
+
+#endif  // nsBaseAppShell_h__
diff --git a/widget/nsBaseClipboard.cpp b/widget/nsBaseClipboard.cpp
new file mode 100644
index 0000000000..40af1de388
--- /dev/null
+++ b/widget/nsBaseClipboard.cpp
@@ -0,0 +1,1313 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsBaseClipboard.h"
+
+#include "ContentAnalysis.h"
+#include "mozilla/Components.h"
+#include "mozilla/contentanalysis/ContentAnalysisIPCTypes.h"
+#include "mozilla/dom/BindingUtils.h"
+#include "mozilla/dom/CanonicalBrowsingContext.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/PromiseNativeHandler.h"
+#include "mozilla/dom/WindowGlobalParent.h"
+#include "mozilla/dom/WindowContext.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/MoveOnlyFunction.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/Services.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsContentUtils.h"
+#include "nsFocusManager.h"
+#include "nsIClipboardOwner.h"
+#include "nsIPromptService.h"
+#include "nsISupportsPrimitives.h"
+#include "nsError.h"
+#include "nsXPCOM.h"
+
+using mozilla::GenericPromise;
+using mozilla::LogLevel;
+using mozilla::UniquePtr;
+using mozilla::dom::BrowsingContext;
+using mozilla::dom::CanonicalBrowsingContext;
+using mozilla::dom::ClipboardCapabilities;
+using mozilla::dom::Document;
+
+static const int32_t kGetAvailableFlavorsRetryCount = 5;
+
+namespace {
+
+struct ClipboardGetRequest {
+  ClipboardGetRequest(const nsTArray<nsCString>& aFlavorList,
+                      nsIAsyncClipboardGetCallback* aCallback)
+      : mFlavorList(aFlavorList.Clone()), mCallback(aCallback) {}
+
+  const nsTArray<nsCString> mFlavorList;
+  const nsCOMPtr<nsIAsyncClipboardGetCallback> mCallback;
+};
+
+class UserConfirmationRequest final
+    : public mozilla::dom::PromiseNativeHandler {
+ public:
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS(UserConfirmationRequest)
+
+  UserConfirmationRequest(int32_t aClipboardType,
+                          Document* aRequestingChromeDocument,
+                          nsIPrincipal* aRequestingPrincipal,
+                          nsBaseClipboard* aClipboard,
+                          mozilla::dom::WindowContext* aRequestingWindowContext)
+      : mClipboardType(aClipboardType),
+        mRequestingChromeDocument(aRequestingChromeDocument),
+        mRequestingPrincipal(aRequestingPrincipal),
+        mClipboard(aClipboard),
+        mRequestingWindowContext(aRequestingWindowContext) {
+    MOZ_ASSERT(
+        mClipboard->nsIClipboard::IsClipboardTypeSupported(aClipboardType));
+  }
+
+  void ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                        mozilla::ErrorResult& aRv) override;
+
+  void RejectedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                        mozilla::ErrorResult& aRv) override;
+
+  bool IsEqual(int32_t aClipboardType, Document* aRequestingChromeDocument,
+               nsIPrincipal* aRequestingPrincipal,
+               mozilla::dom::WindowContext* aRequestingWindowContext) const {
+    if (!(ClipboardType() == aClipboardType &&
+          RequestingChromeDocument() == aRequestingChromeDocument &&
+          RequestingPrincipal()->Equals(aRequestingPrincipal) &&
+          (mRequestingWindowContext && aRequestingWindowContext))) {
+      return false;
+    }
+    // Only check requesting window contexts if content analysis is active
+    nsCOMPtr<nsIContentAnalysis> contentAnalysis =
+        mozilla::components::nsIContentAnalysis::Service();
+    if (!contentAnalysis) {
+      return false;
+    }
+
+    bool contentAnalysisIsActive;
+    nsresult rv = contentAnalysis->GetIsActive(&contentAnalysisIsActive);
+    if (MOZ_LIKELY(NS_FAILED(rv) || !contentAnalysisIsActive)) {
+      return true;
+    }
+    return mRequestingWindowContext->Id() == aRequestingWindowContext->Id();
+  }
+
+  int32_t ClipboardType() const { return mClipboardType; }
+
+  Document* RequestingChromeDocument() const {
+    return mRequestingChromeDocument;
+  }
+
+  nsIPrincipal* RequestingPrincipal() const { return mRequestingPrincipal; }
+
+  void AddClipboardGetRequest(const nsTArray<nsCString>& aFlavorList,
+                              nsIAsyncClipboardGetCallback* aCallback) {
+    MOZ_ASSERT(!aFlavorList.IsEmpty());
+    MOZ_ASSERT(aCallback);
+    mPendingClipboardGetRequests.AppendElement(
+        mozilla::MakeUnique<ClipboardGetRequest>(aFlavorList, aCallback));
+  }
+
+  void RejectPendingClipboardGetRequests(nsresult aError) {
+    MOZ_ASSERT(NS_FAILED(aError));
+    auto requests = std::move(mPendingClipboardGetRequests);
+    for (const auto& request : requests) {
+      MOZ_ASSERT(request);
+      MOZ_ASSERT(request->mCallback);
+      request->mCallback->OnError(aError);
+    }
+  }
+
+  void ProcessPendingClipboardGetRequests() {
+    auto requests = std::move(mPendingClipboardGetRequests);
+    for (const auto& request : requests) {
+      MOZ_ASSERT(request);
+      MOZ_ASSERT(!request->mFlavorList.IsEmpty());
+      MOZ_ASSERT(request->mCallback);
+      mClipboard->AsyncGetDataInternal(request->mFlavorList, mClipboardType,
+                                       mRequestingWindowContext,
+                                       request->mCallback);
+    }
+  }
+
+  nsTArray<UniquePtr<ClipboardGetRequest>>& GetPendingClipboardGetRequests() {
+    return mPendingClipboardGetRequests;
+  }
+
+ private:
+  ~UserConfirmationRequest() = default;
+
+  const int32_t mClipboardType;
+  RefPtr<Document> mRequestingChromeDocument;
+  const nsCOMPtr<nsIPrincipal> mRequestingPrincipal;
+  const RefPtr<nsBaseClipboard> mClipboard;
+  const RefPtr<mozilla::dom::WindowContext> mRequestingWindowContext;
+  // Track the pending read requests that wait for user confirmation.
+  nsTArray<UniquePtr<ClipboardGetRequest>> mPendingClipboardGetRequests;
+};
+
+NS_IMPL_CYCLE_COLLECTION(UserConfirmationRequest, mRequestingChromeDocument)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(UserConfirmationRequest)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(UserConfirmationRequest)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(UserConfirmationRequest)
+
+static mozilla::StaticRefPtr<UserConfirmationRequest> sUserConfirmationRequest;
+
+void UserConfirmationRequest::ResolvedCallback(JSContext* aCx,
+                                               JS::Handle<JS::Value> aValue,
+                                               mozilla::ErrorResult& aRv) {
+  MOZ_DIAGNOSTIC_ASSERT(sUserConfirmationRequest == this);
+  sUserConfirmationRequest = nullptr;
+
+  JS::Rooted<JSObject*> detailObj(aCx, &aValue.toObject());
+  nsCOMPtr<nsIPropertyBag2> propBag;
+  nsresult rv = mozilla::dom::UnwrapArg<nsIPropertyBag2>(
+      aCx, detailObj, getter_AddRefs(propBag));
+  if (NS_FAILED(rv)) {
+    RejectPendingClipboardGetRequests(rv);
+    return;
+  }
+
+  bool result = false;
+  rv = propBag->GetPropertyAsBool(u"ok"_ns, &result);
+  if (NS_FAILED(rv)) {
+    RejectPendingClipboardGetRequests(rv);
+    return;
+  }
+
+  if (!result) {
+    RejectPendingClipboardGetRequests(NS_ERROR_DOM_NOT_ALLOWED_ERR);
+    return;
+  }
+
+  ProcessPendingClipboardGetRequests();
+}
+
+void UserConfirmationRequest::RejectedCallback(JSContext* aCx,
+                                               JS::Handle<JS::Value> aValue,
+                                               mozilla::ErrorResult& aRv) {
+  MOZ_DIAGNOSTIC_ASSERT(sUserConfirmationRequest == this);
+  sUserConfirmationRequest = nullptr;
+  RejectPendingClipboardGetRequests(NS_ERROR_FAILURE);
+}
+
+}  // namespace
+
+NS_IMPL_ISUPPORTS(nsBaseClipboard::AsyncSetClipboardData,
+                  nsIAsyncSetClipboardData)
+
+nsBaseClipboard::AsyncSetClipboardData::AsyncSetClipboardData(
+    int32_t aClipboardType, nsBaseClipboard* aClipboard,
+    nsIAsyncClipboardRequestCallback* aCallback)
+    : mClipboardType(aClipboardType),
+      mClipboard(aClipboard),
+      mCallback(aCallback) {
+  MOZ_ASSERT(mClipboard);
+  MOZ_ASSERT(
+      mClipboard->nsIClipboard::IsClipboardTypeSupported(mClipboardType));
+}
+
+NS_IMETHODIMP
+nsBaseClipboard::AsyncSetClipboardData::SetData(nsITransferable* aTransferable,
+                                                nsIClipboardOwner* aOwner) {
+  MOZ_CLIPBOARD_LOG("AsyncSetClipboardData::SetData (%p): clipboard=%d", this,
+                    mClipboardType);
+
+  if (!IsValid()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+    nsTArray<nsCString> flavors;
+    if (NS_SUCCEEDED(aTransferable->FlavorsTransferableCanImport(flavors))) {
+      for (const auto& flavor : flavors) {
+        MOZ_CLIPBOARD_LOG("    MIME %s", flavor.get());
+      }
+    }
+  }
+
+  MOZ_ASSERT(mClipboard);
+  MOZ_ASSERT(
+      mClipboard->nsIClipboard::IsClipboardTypeSupported(mClipboardType));
+  MOZ_DIAGNOSTIC_ASSERT(mClipboard->mPendingWriteRequests[mClipboardType] ==
+                        this);
+
+  RefPtr<AsyncSetClipboardData> request =
+      std::move(mClipboard->mPendingWriteRequests[mClipboardType]);
+  nsresult rv = mClipboard->SetData(aTransferable, aOwner, mClipboardType);
+  MaybeNotifyCallback(rv);
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsBaseClipboard::AsyncSetClipboardData::Abort(nsresult aReason) {
+  // Note: This may be called during destructor, so it should not attempt to
+  // take a reference to mClipboard.
+
+  if (!IsValid() || !NS_FAILED(aReason)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  MaybeNotifyCallback(aReason);
+  return NS_OK;
+}
+
+void nsBaseClipboard::AsyncSetClipboardData::MaybeNotifyCallback(
+    nsresult aResult) {
+  // Note: This may be called during destructor, so it should not attempt to
+  // take a reference to mClipboard.
+
+  MOZ_ASSERT(IsValid());
+  if (nsCOMPtr<nsIAsyncClipboardRequestCallback> callback =
+          mCallback.forget()) {
+    callback->OnComplete(aResult);
+  }
+  // Once the callback is notified, setData should not be allowed, so invalidate
+  // this request.
+  mClipboard = nullptr;
+}
+
+void nsBaseClipboard::RejectPendingAsyncSetDataRequestIfAny(
+    int32_t aClipboardType) {
+  MOZ_ASSERT(nsIClipboard::IsClipboardTypeSupported(aClipboardType));
+  auto& request = mPendingWriteRequests[aClipboardType];
+  if (request) {
+    request->Abort(NS_ERROR_ABORT);
+    request = nullptr;
+  }
+}
+
+NS_IMETHODIMP nsBaseClipboard::AsyncSetData(
+    int32_t aWhichClipboard, nsIAsyncClipboardRequestCallback* aCallback,
+    nsIAsyncSetClipboardData** _retval) {
+  MOZ_CLIPBOARD_LOG("%s: clipboard=%d", __FUNCTION__, aWhichClipboard);
+
+  *_retval = nullptr;
+  if (!nsIClipboard::IsClipboardTypeSupported(aWhichClipboard)) {
+    MOZ_CLIPBOARD_LOG("%s: clipboard %d is not supported.", __FUNCTION__,
+                      aWhichClipboard);
+    return NS_ERROR_DOM_NOT_SUPPORTED_ERR;
+  }
+
+  // Reject existing pending AsyncSetData request if any.
+  RejectPendingAsyncSetDataRequestIfAny(aWhichClipboard);
+
+  // Create a new AsyncSetClipboardData.
+  RefPtr<AsyncSetClipboardData> request =
+      mozilla::MakeRefPtr<AsyncSetClipboardData>(aWhichClipboard, this,
+                                                 aCallback);
+  mPendingWriteRequests[aWhichClipboard] = request;
+  request.forget(_retval);
+  return NS_OK;
+}
+
+namespace {
+class SafeContentAnalysisResultCallback final
+    : public nsIContentAnalysisCallback {
+ public:
+  explicit SafeContentAnalysisResultCallback(
+      std::function<void(RefPtr<nsIContentAnalysisResult>&&)> aResolver)
+      : mResolver(std::move(aResolver)) {}
+  void Callback(RefPtr<nsIContentAnalysisResult>&& aResult) {
+    MOZ_ASSERT(mResolver, "Called SafeContentAnalysisResultCallback twice!");
+    if (auto resolver = std::move(mResolver)) {
+      resolver(std::move(aResult));
+    }
+  }
+
+  NS_IMETHODIMP ContentResult(nsIContentAnalysisResponse* aResponse) override {
+    using namespace mozilla::contentanalysis;
+    RefPtr<ContentAnalysisResult> result =
+        ContentAnalysisResult::FromContentAnalysisResponse(aResponse);
+    Callback(result);
+    return NS_OK;
+  }
+
+  NS_IMETHODIMP Error(nsresult aError) override {
+    using namespace mozilla::contentanalysis;
+    Callback(ContentAnalysisResult::FromNoResult(
+        NoContentAnalysisResult::ERROR_OTHER));
+    return NS_OK;
+  }
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+ private:
+  // Private destructor to force this to be allocated in a RefPtr, which is
+  // necessary for safe usage.
+  ~SafeContentAnalysisResultCallback() {
+    MOZ_ASSERT(!mResolver, "SafeContentAnalysisResultCallback never called!");
+  }
+  mozilla::MoveOnlyFunction<void(RefPtr<nsIContentAnalysisResult>&&)> mResolver;
+};
+NS_IMPL_ISUPPORTS(SafeContentAnalysisResultCallback,
+                  nsIContentAnalysisCallback);
+}  // namespace
+
+// Returning:
+//  - true means a content analysis request was fired
+//  - false means there is no text data in the transferable
+//  - NoContentAnalysisResult means there was an error
+static mozilla::Result<bool, mozilla::contentanalysis::NoContentAnalysisResult>
+CheckClipboardContentAnalysisAsText(
+    uint64_t aInnerWindowId, SafeContentAnalysisResultCallback* aResolver,
+    nsIURI* aDocumentURI, nsIContentAnalysis* aContentAnalysis,
+    nsITransferable* aTextTrans) {
+  using namespace mozilla::contentanalysis;
+
+  nsCOMPtr<nsISupports> transferData;
+  if (NS_FAILED(aTextTrans->GetTransferData(kTextMime,
+                                            getter_AddRefs(transferData)))) {
+    return false;
+  }
+  nsCOMPtr<nsISupportsString> textData = do_QueryInterface(transferData);
+  if (MOZ_UNLIKELY(!textData)) {
+    return false;
+  }
+  nsString text;
+  if (NS_FAILED(textData->GetData(text))) {
+    return mozilla::Err(NoContentAnalysisResult::ERROR_OTHER);
+  }
+  RefPtr<mozilla::dom::WindowGlobalParent> window =
+      mozilla::dom::WindowGlobalParent::GetByInnerWindowId(aInnerWindowId);
+  if (!window) {
+    // The window has gone away in the meantime
+    return mozilla::Err(NoContentAnalysisResult::ERROR_OTHER);
+  }
+  nsCOMPtr<nsIContentAnalysisRequest> contentAnalysisRequest =
+      new ContentAnalysisRequest(
+          nsIContentAnalysisRequest::AnalysisType::eBulkDataEntry,
+          std::move(text), false, EmptyCString(), aDocumentURI,
+          nsIContentAnalysisRequest::OperationType::eClipboard, window);
+  nsresult rv = aContentAnalysis->AnalyzeContentRequestCallback(
+      contentAnalysisRequest, /* aAutoAcknowledge */ true, aResolver);
+  if (NS_FAILED(rv)) {
+    return mozilla::Err(NoContentAnalysisResult::ERROR_OTHER);
+  }
+  return true;
+}
+
+// Returning:
+//  - true means a content analysis request was fired
+//  - false means there is no file data in the transferable
+//  - NoContentAnalysisResult means there was an error
+static mozilla::Result<bool, mozilla::contentanalysis::NoContentAnalysisResult>
+CheckClipboardContentAnalysisAsFile(
+    uint64_t aInnerWindowId, SafeContentAnalysisResultCallback* aResolver,
+    nsIURI* aDocumentURI, nsIContentAnalysis* aContentAnalysis,
+    nsITransferable* aFileTrans) {
+  using namespace mozilla::contentanalysis;
+
+  nsCOMPtr<nsISupports> transferData;
+  nsresult rv =
+      aFileTrans->GetTransferData(kFileMime, getter_AddRefs(transferData));
+  nsString filePath;
+  if (NS_SUCCEEDED(rv)) {
+    if (nsCOMPtr<nsIFile> file = do_QueryInterface(transferData)) {
+      rv = file->GetPath(filePath);
+    } else {
+      MOZ_ASSERT_UNREACHABLE("clipboard data had kFileMime but no nsIFile!");
+      return mozilla::Err(NoContentAnalysisResult::ERROR_OTHER);
+    }
+  }
+  if (NS_FAILED(rv) || filePath.IsEmpty()) {
+    return false;
+  }
+  RefPtr<mozilla::dom::WindowGlobalParent> window =
+      mozilla::dom::WindowGlobalParent::GetByInnerWindowId(aInnerWindowId);
+  if (!window) {
+    // The window has gone away in the meantime
+    return mozilla::Err(NoContentAnalysisResult::ERROR_OTHER);
+  }
+  // Let the content analysis code calculate the digest
+  nsCOMPtr<nsIContentAnalysisRequest> contentAnalysisRequest =
+      new ContentAnalysisRequest(
+          nsIContentAnalysisRequest::AnalysisType::eBulkDataEntry,
+          std::move(filePath), true, EmptyCString(), aDocumentURI,
+          nsIContentAnalysisRequest::OperationType::eCustomDisplayString,
+          window);
+  rv = aContentAnalysis->AnalyzeContentRequestCallback(
+      contentAnalysisRequest,
+      /* aAutoAcknowledge */ true, aResolver);
+  if (NS_FAILED(rv)) {
+    return mozilla::Err(NoContentAnalysisResult::ERROR_OTHER);
+  }
+  return true;
+}
+
+static void CheckClipboardContentAnalysis(
+    mozilla::dom::WindowGlobalParent* aWindow, nsITransferable* aTransferable,
+    SafeContentAnalysisResultCallback* aResolver) {
+  using namespace mozilla::contentanalysis;
+
+  // Content analysis is only needed if an outside webpage has access to
+  // the data. So, skip content analysis if there is:
+  //  - no associated window (for example, scripted clipboard read by system
+  //  code)
+  //  - the window is a chrome docshell
+  //  - the window is being rendered in the parent process (for example,
+  //  about:support and the like)
+  if (!aWindow || aWindow->GetBrowsingContext()->IsChrome() ||
+      aWindow->IsInProcess()) {
+    aResolver->Callback(ContentAnalysisResult::FromNoResult(
+        NoContentAnalysisResult::CONTEXT_EXEMPT_FROM_CONTENT_ANALYSIS));
+    return;
+  }
+  nsCOMPtr<nsIContentAnalysis> contentAnalysis =
+      mozilla::components::nsIContentAnalysis::Service();
+  if (!contentAnalysis) {
+    aResolver->Callback(ContentAnalysisResult::FromNoResult(
+        NoContentAnalysisResult::ERROR_OTHER));
+    return;
+  }
+
+  bool contentAnalysisIsActive;
+  nsresult rv = contentAnalysis->GetIsActive(&contentAnalysisIsActive);
+  if (MOZ_LIKELY(NS_FAILED(rv) || !contentAnalysisIsActive)) {
+    aResolver->Callback(ContentAnalysisResult::FromNoResult(
+        NoContentAnalysisResult::CONTENT_ANALYSIS_NOT_ACTIVE));
+    return;
+  }
+
+  nsCOMPtr<nsIURI> currentURI = aWindow->Canonical()->GetDocumentURI();
+  uint64_t innerWindowId = aWindow->InnerWindowId();
+  nsTArray<nsCString> flavors;
+  rv = aTransferable->FlavorsTransferableCanExport(flavors);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    aResolver->Callback(ContentAnalysisResult::FromNoResult(
+        NoContentAnalysisResult::ERROR_OTHER));
+    return;
+  }
+  bool keepChecking = true;
+  if (flavors.Contains(kFileMime)) {
+    auto fileResult = CheckClipboardContentAnalysisAsFile(
+        innerWindowId, aResolver, currentURI, contentAnalysis, aTransferable);
+
+    if (fileResult.isErr()) {
+      aResolver->Callback(
+          ContentAnalysisResult::FromNoResult(fileResult.unwrapErr()));
+      return;
+    }
+    keepChecking = !fileResult.unwrap();
+  }
+  if (keepChecking) {
+    // Failed to get the clipboard data as a file, so try as text
+    auto textResult = CheckClipboardContentAnalysisAsText(
+        innerWindowId, aResolver, currentURI, contentAnalysis, aTransferable);
+    if (textResult.isErr()) {
+      aResolver->Callback(
+          ContentAnalysisResult::FromNoResult(textResult.unwrapErr()));
+      return;
+    }
+    if (!textResult.unwrap()) {
+      // Couldn't get file or text data from this
+      aResolver->Callback(ContentAnalysisResult::FromNoResult(
+          NoContentAnalysisResult::ERROR_COULD_NOT_GET_DATA));
+      return;
+    }
+  }
+}
+
+static bool CheckClipboardContentAnalysisSync(
+    mozilla::dom::WindowGlobalParent* aWindow,
+    const nsCOMPtr<nsITransferable>& trans) {
+  bool requestDone = false;
+  RefPtr<nsIContentAnalysisResult> result;
+  auto callback = mozilla::MakeRefPtr<SafeContentAnalysisResultCallback>(
+      [&requestDone, &result](RefPtr<nsIContentAnalysisResult>&& aResult) {
+        result = std::move(aResult);
+        requestDone = true;
+      });
+  CheckClipboardContentAnalysis(aWindow, trans, callback);
+  mozilla::SpinEventLoopUntil("CheckClipboardContentAnalysisSync"_ns,
+                              [&requestDone]() -> bool { return requestDone; });
+  return result->GetShouldAllowContent();
+}
+
+nsBaseClipboard::nsBaseClipboard(const ClipboardCapabilities& aClipboardCaps)
+    : mClipboardCaps(aClipboardCaps) {
+  using mozilla::MakeUnique;
+  // Initialize clipboard cache.
+  mCaches[kGlobalClipboard] = MakeUnique<ClipboardCache>();
+  if (mClipboardCaps.supportsSelectionClipboard()) {
+    mCaches[kSelectionClipboard] = MakeUnique<ClipboardCache>();
+  }
+  if (mClipboardCaps.supportsFindClipboard()) {
+    mCaches[kFindClipboard] = MakeUnique<ClipboardCache>();
+  }
+  if (mClipboardCaps.supportsSelectionCache()) {
+    mCaches[kSelectionCache] = MakeUnique<ClipboardCache>();
+  }
+}
+
+nsBaseClipboard::~nsBaseClipboard() {
+  for (auto& request : mPendingWriteRequests) {
+    if (request) {
+      request->Abort(NS_ERROR_ABORT);
+      request = nullptr;
+    }
+  }
+}
+
+NS_IMPL_ISUPPORTS(nsBaseClipboard, nsIClipboard)
+
+/**
+ * Sets the transferable object
+ *
+ */
+NS_IMETHODIMP nsBaseClipboard::SetData(nsITransferable* aTransferable,
+                                       nsIClipboardOwner* aOwner,
+                                       int32_t aWhichClipboard) {
+  NS_ASSERTION(aTransferable, "clipboard given a null transferable");
+
+  MOZ_CLIPBOARD_LOG("%s: clipboard=%d", __FUNCTION__, aWhichClipboard);
+
+  if (!nsIClipboard::IsClipboardTypeSupported(aWhichClipboard)) {
+    MOZ_CLIPBOARD_LOG("%s: clipboard %d is not supported.", __FUNCTION__,
+                      aWhichClipboard);
+    return NS_ERROR_FAILURE;
+  }
+
+  if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+    nsTArray<nsCString> flavors;
+    if (NS_SUCCEEDED(aTransferable->FlavorsTransferableCanImport(flavors))) {
+      for (const auto& flavor : flavors) {
+        MOZ_CLIPBOARD_LOG("    MIME %s", flavor.get());
+      }
+    }
+  }
+
+  const auto& clipboardCache = mCaches[aWhichClipboard];
+  MOZ_ASSERT(clipboardCache);
+  if (aTransferable == clipboardCache->GetTransferable() &&
+      aOwner == clipboardCache->GetClipboardOwner()) {
+    MOZ_CLIPBOARD_LOG("%s: skipping update.", __FUNCTION__);
+    return NS_OK;
+  }
+
+  clipboardCache->Clear();
+
+  nsresult rv = NS_ERROR_FAILURE;
+  if (aTransferable) {
+    mIgnoreEmptyNotification = true;
+    // Reject existing pending asyncSetData request if any.
+    RejectPendingAsyncSetDataRequestIfAny(aWhichClipboard);
+    rv = SetNativeClipboardData(aTransferable, aWhichClipboard);
+    mIgnoreEmptyNotification = false;
+  }
+  if (NS_FAILED(rv)) {
+    MOZ_CLIPBOARD_LOG("%s: setting native clipboard data failed.",
+                      __FUNCTION__);
+    return rv;
+  }
+
+  auto result = GetNativeClipboardSequenceNumber(aWhichClipboard);
+  if (result.isErr()) {
+    MOZ_CLIPBOARD_LOG("%s: getting native clipboard change count failed.",
+                      __FUNCTION__);
+    return result.unwrapErr();
+  }
+
+  clipboardCache->Update(aTransferable, aOwner, result.unwrap());
+  return NS_OK;
+}
+
+nsresult nsBaseClipboard::GetDataFromClipboardCache(
+    nsITransferable* aTransferable, int32_t aClipboardType) {
+  MOZ_ASSERT(aTransferable);
+  MOZ_ASSERT(nsIClipboard::IsClipboardTypeSupported(aClipboardType));
+  MOZ_ASSERT(mozilla::StaticPrefs::widget_clipboard_use_cached_data_enabled());
+
+  const auto* clipboardCache = GetClipboardCacheIfValid(aClipboardType);
+  if (!clipboardCache) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return clipboardCache->GetData(aTransferable);
+}
+
+/**
+ * Gets the transferable object from system clipboard.
+ */
+NS_IMETHODIMP nsBaseClipboard::GetData(
+    nsITransferable* aTransferable, int32_t aWhichClipboard,
+    mozilla::dom::WindowContext* aWindowContext) {
+  MOZ_CLIPBOARD_LOG("%s: clipboard=%d", __FUNCTION__, aWhichClipboard);
+
+  if (!aTransferable) {
+    NS_ASSERTION(false, "clipboard given a null transferable");
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!nsIClipboard::IsClipboardTypeSupported(aWhichClipboard)) {
+    MOZ_CLIPBOARD_LOG("%s: clipboard %d is not supported.", __FUNCTION__,
+                      aWhichClipboard);
+    return NS_ERROR_FAILURE;
+  }
+
+  if (mozilla::StaticPrefs::widget_clipboard_use_cached_data_enabled()) {
+    // If we were the last ones to put something on the native clipboard, then
+    // just use the cached transferable. Otherwise clear it because it isn't
+    // relevant any more.
+    if (NS_SUCCEEDED(
+            GetDataFromClipboardCache(aTransferable, aWhichClipboard))) {
+      // maybe try to fill in more types? Is there a point?
+      if (!CheckClipboardContentAnalysisSync(aWindowContext->Canonical(),
+                                             aTransferable)) {
+        aTransferable->ClearAllData();
+        return NS_ERROR_CONTENT_BLOCKED;
+      }
+      return NS_OK;
+    }
+
+    // at this point we can't satisfy the request from cache data so let's look
+    // for things other people put on the system clipboard
+  }
+  nsresult rv = GetNativeClipboardData(aTransferable, aWhichClipboard);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  if (!CheckClipboardContentAnalysisSync(aWindowContext->Canonical(),
+                                         aTransferable)) {
+    aTransferable->ClearAllData();
+    return NS_ERROR_CONTENT_BLOCKED;
+  }
+  return NS_OK;
+}
+
+void nsBaseClipboard::MaybeRetryGetAvailableFlavors(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard,
+    nsIAsyncClipboardGetCallback* aCallback, int32_t aRetryCount,
+    mozilla::dom::WindowContext* aRequestingWindowContext) {
+  // Note we have to get the clipboard sequence number first before the actual
+  // read. This is to use it to verify the clipboard data is still the one we
+  // try to read, instead of the later state.
+  auto sequenceNumberOrError =
+      GetNativeClipboardSequenceNumber(aWhichClipboard);
+  if (sequenceNumberOrError.isErr()) {
+    MOZ_CLIPBOARD_LOG("%s: unable to get sequence number for clipboard %d.",
+                      __FUNCTION__, aWhichClipboard);
+    aCallback->OnError(sequenceNumberOrError.unwrapErr());
+    return;
+  }
+
+  int32_t sequenceNumber = sequenceNumberOrError.unwrap();
+  AsyncHasNativeClipboardDataMatchingFlavors(
+      aFlavorList, aWhichClipboard,
+      [self = RefPtr{this}, callback = nsCOMPtr{aCallback}, aWhichClipboard,
+       aRetryCount, flavorList = aFlavorList.Clone(), sequenceNumber,
+       requestingWindowContext =
+           RefPtr{aRequestingWindowContext}](auto aFlavorsOrError) {
+        if (aFlavorsOrError.isErr()) {
+          MOZ_CLIPBOARD_LOG(
+              "%s: unable to get available flavors for clipboard %d.",
+              __FUNCTION__, aWhichClipboard);
+          callback->OnError(aFlavorsOrError.unwrapErr());
+          return;
+        }
+
+        auto sequenceNumberOrError =
+            self->GetNativeClipboardSequenceNumber(aWhichClipboard);
+        if (sequenceNumberOrError.isErr()) {
+          MOZ_CLIPBOARD_LOG(
+              "%s: unable to get sequence number for clipboard %d.",
+              __FUNCTION__, aWhichClipboard);
+          callback->OnError(sequenceNumberOrError.unwrapErr());
+          return;
+        }
+
+        if (sequenceNumber == sequenceNumberOrError.unwrap()) {
+          auto asyncGetClipboardData =
+              mozilla::MakeRefPtr<AsyncGetClipboardData>(
+                  aWhichClipboard, sequenceNumber,
+                  std::move(aFlavorsOrError.unwrap()), false, self,
+                  requestingWindowContext);
+          callback->OnSuccess(asyncGetClipboardData);
+          return;
+        }
+
+        if (aRetryCount > 0) {
+          MOZ_CLIPBOARD_LOG(
+              "%s: clipboard=%d, ignore the data due to the sequence number "
+              "doesn't match, retry (%d) ..",
+              __FUNCTION__, aWhichClipboard, aRetryCount);
+          self->MaybeRetryGetAvailableFlavors(flavorList, aWhichClipboard,
+                                              callback, aRetryCount - 1,
+                                              requestingWindowContext);
+          return;
+        }
+
+        MOZ_DIAGNOSTIC_ASSERT(false, "How can this happen?!?");
+        callback->OnError(NS_ERROR_FAILURE);
+      });
+}
+
+NS_IMETHODIMP nsBaseClipboard::AsyncGetData(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard,
+    mozilla::dom::WindowContext* aRequestingWindowContext,
+    nsIPrincipal* aRequestingPrincipal,
+    nsIAsyncClipboardGetCallback* aCallback) {
+  MOZ_CLIPBOARD_LOG("%s: clipboard=%d", __FUNCTION__, aWhichClipboard);
+
+  if (!aCallback || !aRequestingPrincipal || aFlavorList.IsEmpty()) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  if (!nsIClipboard::IsClipboardTypeSupported(aWhichClipboard)) {
+    MOZ_CLIPBOARD_LOG("%s: clipboard %d is not supported.", __FUNCTION__,
+                      aWhichClipboard);
+    return NS_ERROR_FAILURE;
+  }
+
+  // We want to disable security check for automated tests that have the pref
+  // set to true, or extension that have clipboard read permission.
+  if (mozilla::StaticPrefs::
+          dom_events_testing_asyncClipboard_DoNotUseDirectly() ||
+      nsContentUtils::PrincipalHasPermission(*aRequestingPrincipal,
+                                             nsGkAtoms::clipboardRead)) {
+    AsyncGetDataInternal(aFlavorList, aWhichClipboard, aRequestingWindowContext,
+                         aCallback);
+    return NS_OK;
+  }
+
+  // If cache data is valid, we are the last ones to put something on the native
+  // clipboard, then check if the data is from the same-origin page,
+  if (auto* clipboardCache = GetClipboardCacheIfValid(aWhichClipboard)) {
+    nsCOMPtr<nsITransferable> trans = clipboardCache->GetTransferable();
+    MOZ_ASSERT(trans);
+
+    if (nsCOMPtr<nsIPrincipal> principal = trans->GetRequestingPrincipal()) {
+      if (aRequestingPrincipal->Subsumes(principal)) {
+        MOZ_CLIPBOARD_LOG("%s: native clipboard data is from same-origin page.",
+                          __FUNCTION__);
+        AsyncGetDataInternal(aFlavorList, aWhichClipboard,
+                             aRequestingWindowContext, aCallback);
+        return NS_OK;
+      }
+    }
+  }
+
+  // TODO: enable showing the "Paste" button in this case; see bug 1773681.
+  if (aRequestingPrincipal->GetIsAddonOrExpandedAddonPrincipal()) {
+    MOZ_CLIPBOARD_LOG("%s: Addon without read permission.", __FUNCTION__);
+    return aCallback->OnError(NS_ERROR_FAILURE);
+  }
+
+  RequestUserConfirmation(aWhichClipboard, aFlavorList,
+                          aRequestingWindowContext, aRequestingPrincipal,
+                          aCallback);
+  return NS_OK;
+}
+
+void nsBaseClipboard::AsyncGetDataInternal(
+    const nsTArray<nsCString>& aFlavorList, int32_t aClipboardType,
+    mozilla::dom::WindowContext* aRequestingWindowContext,
+    nsIAsyncClipboardGetCallback* aCallback) {
+  MOZ_ASSERT(nsIClipboard::IsClipboardTypeSupported(aClipboardType));
+
+  if (mozilla::StaticPrefs::widget_clipboard_use_cached_data_enabled()) {
+    // If we were the last ones to put something on the native clipboard, then
+    // just use the cached transferable. Otherwise clear it because it isn't
+    // relevant any more.
+    if (auto* clipboardCache = GetClipboardCacheIfValid(aClipboardType)) {
+      nsITransferable* cachedTransferable = clipboardCache->GetTransferable();
+      MOZ_ASSERT(cachedTransferable);
+
+      nsTArray<nsCString> transferableFlavors;
+      if (NS_SUCCEEDED(cachedTransferable->FlavorsTransferableCanExport(
+              transferableFlavors))) {
+        nsTArray<nsCString> results;
+        for (const auto& transferableFlavor : transferableFlavors) {
+          for (const auto& flavor : aFlavorList) {
+            // XXX We need special check for image as we always put the
+            // image as "native" on the clipboard.
+            if (transferableFlavor.Equals(flavor) ||
+                (transferableFlavor.Equals(kNativeImageMime) &&
+                 nsContentUtils::IsFlavorImage(flavor))) {
+              MOZ_CLIPBOARD_LOG("    has %s", flavor.get());
+              results.AppendElement(flavor);
+            }
+          }
+        }
+
+        // XXX Do we need to check system clipboard for the flavors that cannot
+        // be found in cache?
+        auto asyncGetClipboardData = mozilla::MakeRefPtr<AsyncGetClipboardData>(
+            aClipboardType, clipboardCache->GetSequenceNumber(),
+            std::move(results), true, this, aRequestingWindowContext);
+        aCallback->OnSuccess(asyncGetClipboardData);
+        return;
+      }
+    }
+
+    // At this point we can't satisfy the request from cache data so let's look
+    // for things other people put on the system clipboard.
+  }
+
+  MaybeRetryGetAvailableFlavors(aFlavorList, aClipboardType, aCallback,
+                                kGetAvailableFlavorsRetryCount,
+                                aRequestingWindowContext);
+}
+
+NS_IMETHODIMP nsBaseClipboard::EmptyClipboard(int32_t aWhichClipboard) {
+  MOZ_CLIPBOARD_LOG("%s: clipboard=%d", __FUNCTION__, aWhichClipboard);
+
+  if (!nsIClipboard::IsClipboardTypeSupported(aWhichClipboard)) {
+    MOZ_CLIPBOARD_LOG("%s: clipboard %d is not supported.", __FUNCTION__,
+                      aWhichClipboard);
+    return NS_ERROR_FAILURE;
+  }
+
+  EmptyNativeClipboardData(aWhichClipboard);
+
+  const auto& clipboardCache = mCaches[aWhichClipboard];
+  MOZ_ASSERT(clipboardCache);
+
+  if (mIgnoreEmptyNotification) {
+    MOZ_DIAGNOSTIC_ASSERT(!clipboardCache->GetTransferable() &&
+                              !clipboardCache->GetClipboardOwner() &&
+                              clipboardCache->GetSequenceNumber() == -1,
+                          "How did we have data in clipboard cache here?");
+    return NS_OK;
+  }
+
+  clipboardCache->Clear();
+
+  return NS_OK;
+}
+
+mozilla::Result<nsTArray<nsCString>, nsresult>
+nsBaseClipboard::GetFlavorsFromClipboardCache(int32_t aClipboardType) {
+  MOZ_ASSERT(mozilla::StaticPrefs::widget_clipboard_use_cached_data_enabled());
+  MOZ_ASSERT(nsIClipboard::IsClipboardTypeSupported(aClipboardType));
+
+  const auto* clipboardCache = GetClipboardCacheIfValid(aClipboardType);
+  if (!clipboardCache) {
+    return mozilla::Err(NS_ERROR_FAILURE);
+  }
+
+  nsITransferable* cachedTransferable = clipboardCache->GetTransferable();
+  MOZ_ASSERT(cachedTransferable);
+
+  nsTArray<nsCString> flavors;
+  nsresult rv = cachedTransferable->FlavorsTransferableCanExport(flavors);
+  if (NS_FAILED(rv)) {
+    return mozilla::Err(rv);
+  }
+
+  if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+    MOZ_CLIPBOARD_LOG("    Cached transferable types (nums %zu)\n",
+                      flavors.Length());
+    for (const auto& flavor : flavors) {
+      MOZ_CLIPBOARD_LOG("        MIME %s", flavor.get());
+    }
+  }
+
+  return std::move(flavors);
+}
+
+NS_IMETHODIMP
+nsBaseClipboard::HasDataMatchingFlavors(const nsTArray<nsCString>& aFlavorList,
+                                        int32_t aWhichClipboard,
+                                        bool* aOutResult) {
+  MOZ_CLIPBOARD_LOG("%s: clipboard=%d", __FUNCTION__, aWhichClipboard);
+  if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+    MOZ_CLIPBOARD_LOG("    Asking for content clipboard=%i:\n",
+                      aWhichClipboard);
+    for (const auto& flavor : aFlavorList) {
+      MOZ_CLIPBOARD_LOG("        MIME %s", flavor.get());
+    }
+  }
+
+  *aOutResult = false;
+
+  if (mozilla::StaticPrefs::widget_clipboard_use_cached_data_enabled()) {
+    // First, check if we have valid data in our cached transferable.
+    auto flavorsOrError = GetFlavorsFromClipboardCache(aWhichClipboard);
+    if (flavorsOrError.isOk()) {
+      for (const auto& transferableFlavor : flavorsOrError.unwrap()) {
+        for (const auto& flavor : aFlavorList) {
+          if (transferableFlavor.Equals(flavor)) {
+            MOZ_CLIPBOARD_LOG("    has %s", flavor.get());
+            *aOutResult = true;
+            return NS_OK;
+          }
+        }
+      }
+    }
+  }
+
+  auto resultOrError =
+      HasNativeClipboardDataMatchingFlavors(aFlavorList, aWhichClipboard);
+  if (resultOrError.isErr()) {
+    MOZ_CLIPBOARD_LOG(
+        "%s: checking native clipboard data matching flavors falied.",
+        __FUNCTION__);
+    return resultOrError.unwrapErr();
+  }
+
+  *aOutResult = resultOrError.unwrap();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseClipboard::IsClipboardTypeSupported(int32_t aWhichClipboard,
+                                          bool* aRetval) {
+  NS_ENSURE_ARG_POINTER(aRetval);
+  switch (aWhichClipboard) {
+    case kGlobalClipboard:
+      // We always support the global clipboard.
+      *aRetval = true;
+      return NS_OK;
+    case kSelectionClipboard:
+      *aRetval = mClipboardCaps.supportsSelectionClipboard();
+      return NS_OK;
+    case kFindClipboard:
+      *aRetval = mClipboardCaps.supportsFindClipboard();
+      return NS_OK;
+    case kSelectionCache:
+      *aRetval = mClipboardCaps.supportsSelectionCache();
+      return NS_OK;
+    default:
+      *aRetval = false;
+      return NS_OK;
+  }
+}
+
+void nsBaseClipboard::AsyncHasNativeClipboardDataMatchingFlavors(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard,
+    HasMatchingFlavorsCallback&& aCallback) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  MOZ_CLIPBOARD_LOG(
+      "nsBaseClipboard::AsyncHasNativeClipboardDataMatchingFlavors: "
+      "clipboard=%d",
+      aWhichClipboard);
+
+  nsTArray<nsCString> results;
+  for (const auto& flavor : aFlavorList) {
+    auto resultOrError = HasNativeClipboardDataMatchingFlavors(
+        AutoTArray<nsCString, 1>{flavor}, aWhichClipboard);
+    if (resultOrError.isOk() && resultOrError.unwrap()) {
+      results.AppendElement(flavor);
+    }
+  }
+  aCallback(std::move(results));
+}
+
+void nsBaseClipboard::AsyncGetNativeClipboardData(
+    nsITransferable* aTransferable, int32_t aWhichClipboard,
+    GetDataCallback&& aCallback) {
+  aCallback(GetNativeClipboardData(aTransferable, aWhichClipboard));
+}
+
+void nsBaseClipboard::ClearClipboardCache(int32_t aClipboardType) {
+  MOZ_ASSERT(nsIClipboard::IsClipboardTypeSupported(aClipboardType));
+  const mozilla::UniquePtr<ClipboardCache>& cache = mCaches[aClipboardType];
+  MOZ_ASSERT(cache);
+  cache->Clear();
+}
+
+void nsBaseClipboard::RequestUserConfirmation(
+    int32_t aClipboardType, const nsTArray<nsCString>& aFlavorList,
+    mozilla::dom::WindowContext* aWindowContext,
+    nsIPrincipal* aRequestingPrincipal,
+    nsIAsyncClipboardGetCallback* aCallback) {
+  MOZ_ASSERT(nsIClipboard::IsClipboardTypeSupported(aClipboardType));
+  MOZ_ASSERT(aCallback);
+
+  if (!aWindowContext) {
+    aCallback->OnError(NS_ERROR_FAILURE);
+    return;
+  }
+
+  CanonicalBrowsingContext* cbc =
+      CanonicalBrowsingContext::Cast(aWindowContext->GetBrowsingContext());
+  MOZ_ASSERT(
+      cbc->IsContent(),
+      "Should not require user confirmation when access from chrome window");
+
+  RefPtr<CanonicalBrowsingContext> chromeTop = cbc->TopCrossChromeBoundary();
+  Document* chromeDoc = chromeTop ? chromeTop->GetDocument() : nullptr;
+  if (!chromeDoc || !chromeDoc->HasFocus(mozilla::IgnoreErrors())) {
+    MOZ_CLIPBOARD_LOG("%s: reject due to not in the focused window",
+                      __FUNCTION__);
+    aCallback->OnError(NS_ERROR_FAILURE);
+    return;
+  }
+
+  mozilla::dom::Element* activeElementInChromeDoc =
+      chromeDoc->GetActiveElement();
+  if (activeElementInChromeDoc != cbc->Top()->GetEmbedderElement()) {
+    // Reject if the request is not from web content that is in the focused tab.
+    MOZ_CLIPBOARD_LOG("%s: reject due to not in the focused tab", __FUNCTION__);
+    aCallback->OnError(NS_ERROR_FAILURE);
+    return;
+  }
+
+  // If there is a pending user confirmation request, check if we could reuse
+  // it. If not, reject the request.
+  if (sUserConfirmationRequest) {
+    if (sUserConfirmationRequest->IsEqual(
+            aClipboardType, chromeDoc, aRequestingPrincipal, aWindowContext)) {
+      sUserConfirmationRequest->AddClipboardGetRequest(aFlavorList, aCallback);
+      return;
+    }
+
+    aCallback->OnError(NS_ERROR_DOM_NOT_ALLOWED_ERR);
+    return;
+  }
+
+  nsresult rv = NS_ERROR_FAILURE;
+  nsCOMPtr<nsIPromptService> promptService =
+      do_GetService("@mozilla.org/prompter;1", &rv);
+  if (NS_FAILED(rv)) {
+    aCallback->OnError(NS_ERROR_DOM_NOT_ALLOWED_ERR);
+    return;
+  }
+
+  RefPtr<mozilla::dom::Promise> promise;
+  if (NS_FAILED(promptService->ConfirmUserPaste(aWindowContext->Canonical(),
+                                                getter_AddRefs(promise)))) {
+    aCallback->OnError(NS_ERROR_DOM_NOT_ALLOWED_ERR);
+    return;
+  }
+
+  sUserConfirmationRequest = new UserConfirmationRequest(
+      aClipboardType, chromeDoc, aRequestingPrincipal, this, aWindowContext);
+  sUserConfirmationRequest->AddClipboardGetRequest(aFlavorList, aCallback);
+  promise->AppendNativeHandler(sUserConfirmationRequest);
+}
+
+NS_IMPL_ISUPPORTS(nsBaseClipboard::AsyncGetClipboardData,
+                  nsIAsyncGetClipboardData)
+
+nsBaseClipboard::AsyncGetClipboardData::AsyncGetClipboardData(
+    int32_t aClipboardType, int32_t aSequenceNumber,
+    nsTArray<nsCString>&& aFlavors, bool aFromCache,
+    nsBaseClipboard* aClipboard,
+    mozilla::dom::WindowContext* aRequestingWindowContext)
+    : mClipboardType(aClipboardType),
+      mSequenceNumber(aSequenceNumber),
+      mFlavors(std::move(aFlavors)),
+      mFromCache(aFromCache),
+      mClipboard(aClipboard),
+      mRequestingWindowContext(aRequestingWindowContext) {
+  MOZ_ASSERT(mClipboard);
+  MOZ_ASSERT(
+      mClipboard->nsIClipboard::IsClipboardTypeSupported(mClipboardType));
+}
+
+NS_IMETHODIMP nsBaseClipboard::AsyncGetClipboardData::GetValid(
+    bool* aOutResult) {
+  *aOutResult = IsValid();
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBaseClipboard::AsyncGetClipboardData::GetFlavorList(
+    nsTArray<nsCString>& aFlavors) {
+  aFlavors.AppendElements(mFlavors);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBaseClipboard::AsyncGetClipboardData::GetData(
+    nsITransferable* aTransferable,
+    nsIAsyncClipboardRequestCallback* aCallback) {
+  MOZ_CLIPBOARD_LOG("AsyncGetClipboardData::GetData: %p", this);
+
+  if (!aTransferable || !aCallback) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanImport(flavors);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // If the requested flavor is not in the list, throw an error.
+  for (const auto& flavor : flavors) {
+    if (!mFlavors.Contains(flavor)) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  if (!IsValid()) {
+    aCallback->OnComplete(NS_ERROR_FAILURE);
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(mClipboard);
+
+  auto contentAnalysisCallback =
+      mozilla::MakeRefPtr<SafeContentAnalysisResultCallback>(
+          [transferable = nsCOMPtr{aTransferable},
+           callback = nsCOMPtr{aCallback}](
+              RefPtr<nsIContentAnalysisResult>&& aResult) {
+            if (aResult->GetShouldAllowContent()) {
+              callback->OnComplete(NS_OK);
+            } else {
+              transferable->ClearAllData();
+              callback->OnComplete(NS_ERROR_CONTENT_BLOCKED);
+            }
+          });
+
+  if (mFromCache) {
+    const auto* clipboardCache =
+        mClipboard->GetClipboardCacheIfValid(mClipboardType);
+    // `IsValid()` above ensures we should get a valid cache and matched
+    // sequence number here.
+    MOZ_DIAGNOSTIC_ASSERT(clipboardCache);
+    MOZ_DIAGNOSTIC_ASSERT(clipboardCache->GetSequenceNumber() ==
+                          mSequenceNumber);
+    if (NS_SUCCEEDED(clipboardCache->GetData(aTransferable))) {
+      CheckClipboardContentAnalysis(mRequestingWindowContext
+                                        ? mRequestingWindowContext->Canonical()
+                                        : nullptr,
+                                    aTransferable, contentAnalysisCallback);
+      return NS_OK;
+    }
+
+    // At this point we can't satisfy the request from cache data so let's look
+    // for things other people put on the system clipboard.
+  }
+
+  // Since this is an async operation, we need to check if the data is still
+  // valid after we get the result.
+  mClipboard->AsyncGetNativeClipboardData(
+      aTransferable, mClipboardType,
+      [callback = nsCOMPtr{aCallback}, self = RefPtr{this},
+       transferable = nsCOMPtr{aTransferable},
+       contentAnalysisCallback =
+           std::move(contentAnalysisCallback)](nsresult aResult) mutable {
+        if (NS_FAILED(aResult)) {
+          callback->OnComplete(aResult);
+          return;
+        }
+        // `IsValid()` checks the clipboard sequence number to ensure the data
+        // we are requesting is still valid.
+        if (!self->IsValid()) {
+          callback->OnComplete(NS_ERROR_FAILURE);
+          return;
+        }
+        CheckClipboardContentAnalysis(
+            self->mRequestingWindowContext
+                ? self->mRequestingWindowContext->Canonical()
+                : nullptr,
+            transferable, contentAnalysisCallback);
+      });
+  return NS_OK;
+}
+
+bool nsBaseClipboard::AsyncGetClipboardData::IsValid() {
+  if (!mClipboard) {
+    return false;
+  }
+
+  // If the data should from cache, check if cache is still valid or the
+  // sequence numbers are matched.
+  if (mFromCache) {
+    const auto* clipboardCache =
+        mClipboard->GetClipboardCacheIfValid(mClipboardType);
+    if (!clipboardCache) {
+      mClipboard = nullptr;
+      return false;
+    }
+
+    return mSequenceNumber == clipboardCache->GetSequenceNumber();
+  }
+
+  auto resultOrError =
+      mClipboard->GetNativeClipboardSequenceNumber(mClipboardType);
+  if (resultOrError.isErr()) {
+    mClipboard = nullptr;
+    return false;
+  }
+
+  if (mSequenceNumber != resultOrError.unwrap()) {
+    mClipboard = nullptr;
+    return false;
+  }
+
+  return true;
+}
+
+nsBaseClipboard::ClipboardCache* nsBaseClipboard::GetClipboardCacheIfValid(
+    int32_t aClipboardType) {
+  MOZ_ASSERT(nsIClipboard::IsClipboardTypeSupported(aClipboardType));
+
+  const mozilla::UniquePtr<ClipboardCache>& cache = mCaches[aClipboardType];
+  MOZ_ASSERT(cache);
+
+  if (!cache->GetTransferable()) {
+    MOZ_ASSERT(cache->GetSequenceNumber() == -1);
+    return nullptr;
+  }
+
+  auto changeCountOrError = GetNativeClipboardSequenceNumber(aClipboardType);
+  if (changeCountOrError.isErr()) {
+    return nullptr;
+  }
+
+  if (changeCountOrError.unwrap() != cache->GetSequenceNumber()) {
+    // Clipboard cache is invalid, clear it.
+    cache->Clear();
+    return nullptr;
+  }
+
+  return cache.get();
+}
+
+void nsBaseClipboard::ClipboardCache::Clear() {
+  if (mClipboardOwner) {
+    mClipboardOwner->LosingOwnership(mTransferable);
+    mClipboardOwner = nullptr;
+  }
+  mTransferable = nullptr;
+  mSequenceNumber = -1;
+}
+
+nsresult nsBaseClipboard::ClipboardCache::GetData(
+    nsITransferable* aTransferable) const {
+  MOZ_ASSERT(aTransferable);
+  MOZ_ASSERT(mozilla::StaticPrefs::widget_clipboard_use_cached_data_enabled());
+
+  // get flavor list that includes all acceptable flavors (including ones
+  // obtained through conversion)
+  nsTArray<nsCString> flavors;
+  if (NS_FAILED(aTransferable->FlavorsTransferableCanImport(flavors))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  MOZ_ASSERT(mTransferable);
+  for (const auto& flavor : flavors) {
+    nsCOMPtr<nsISupports> dataSupports;
+    // XXX Maybe we need special check for image as we always put the image as
+    // "native" on the clipboard.
+    if (NS_SUCCEEDED(mTransferable->GetTransferData(
+            flavor.get(), getter_AddRefs(dataSupports)))) {
+      MOZ_CLIPBOARD_LOG("%s: getting %s from cache.", __FUNCTION__,
+                        flavor.get());
+      aTransferable->SetTransferData(flavor.get(), dataSupports);
+      // XXX we only read the first available type from native clipboard, so
+      // make cache behave the same.
+      return NS_OK;
+    }
+  }
+
+  return NS_ERROR_FAILURE;
+}
diff --git a/widget/nsBaseClipboard.h b/widget/nsBaseClipboard.h
new file mode 100644
index 0000000000..8f90be725a
--- /dev/null
+++ b/widget/nsBaseClipboard.h
@@ -0,0 +1,220 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsBaseClipboard_h__
+#define nsBaseClipboard_h__
+
+#include "mozilla/dom/PContent.h"
+#include "mozilla/Logging.h"
+#include "mozilla/MoveOnlyFunction.h"
+#include "mozilla/Result.h"
+#include "nsIClipboard.h"
+#include "nsITransferable.h"
+#include "nsCOMPtr.h"
+
+static mozilla::LazyLogModule sWidgetClipboardLog("WidgetClipboard");
+#define MOZ_CLIPBOARD_LOG(...) \
+  MOZ_LOG(sWidgetClipboardLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#define MOZ_CLIPBOARD_LOG_ENABLED() \
+  MOZ_LOG_TEST(sWidgetClipboardLog, mozilla::LogLevel::Debug)
+
+class nsITransferable;
+class nsIClipboardOwner;
+class nsIPrincipal;
+class nsIWidget;
+
+namespace mozilla::dom {
+class WindowContext;
+}  // namespace mozilla::dom
+
+/**
+ * A base clipboard class for all platform, so that they can share the same
+ * implementation.
+ */
+class nsBaseClipboard : public nsIClipboard {
+ public:
+  explicit nsBaseClipboard(
+      const mozilla::dom::ClipboardCapabilities& aClipboardCaps);
+
+  // nsISupports
+  NS_DECL_ISUPPORTS
+
+  // nsIClipboard
+  NS_IMETHOD SetData(nsITransferable* aTransferable, nsIClipboardOwner* aOwner,
+                     int32_t aWhichClipboard) override final;
+  NS_IMETHOD AsyncSetData(int32_t aWhichClipboard,
+                          nsIAsyncClipboardRequestCallback* aCallback,
+                          nsIAsyncSetClipboardData** _retval) override final;
+  NS_IMETHOD GetData(
+      nsITransferable* aTransferable, int32_t aWhichClipboard,
+      mozilla::dom::WindowContext* aWindowContext) override final;
+  NS_IMETHOD AsyncGetData(
+      const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard,
+      mozilla::dom::WindowContext* aRequestingWindowContext,
+      nsIPrincipal* aRequestingPrincipal,
+      nsIAsyncClipboardGetCallback* aCallback) override final;
+  NS_IMETHOD EmptyClipboard(int32_t aWhichClipboard) override final;
+  NS_IMETHOD HasDataMatchingFlavors(const nsTArray<nsCString>& aFlavorList,
+                                    int32_t aWhichClipboard,
+                                    bool* aOutResult) override final;
+  NS_IMETHOD IsClipboardTypeSupported(int32_t aWhichClipboard,
+                                      bool* aRetval) override final;
+
+  void AsyncGetDataInternal(
+      const nsTArray<nsCString>& aFlavorList, int32_t aClipboardType,
+      mozilla::dom::WindowContext* aRequestingWindowContext,
+      nsIAsyncClipboardGetCallback* aCallback);
+
+  using GetDataCallback = mozilla::MoveOnlyFunction<void(nsresult)>;
+  using HasMatchingFlavorsCallback = mozilla::MoveOnlyFunction<void(
+      mozilla::Result<nsTArray<nsCString>, nsresult>)>;
+
+ protected:
+  virtual ~nsBaseClipboard();
+
+  // Implement the native clipboard behavior.
+  NS_IMETHOD SetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) = 0;
+  NS_IMETHOD GetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) = 0;
+  virtual void AsyncGetNativeClipboardData(nsITransferable* aTransferable,
+                                           int32_t aWhichClipboard,
+                                           GetDataCallback&& aCallback);
+  virtual nsresult EmptyNativeClipboardData(int32_t aWhichClipboard) = 0;
+  virtual mozilla::Result<int32_t, nsresult> GetNativeClipboardSequenceNumber(
+      int32_t aWhichClipboard) = 0;
+  virtual mozilla::Result<bool, nsresult> HasNativeClipboardDataMatchingFlavors(
+      const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) = 0;
+  virtual void AsyncHasNativeClipboardDataMatchingFlavors(
+      const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard,
+      HasMatchingFlavorsCallback&& aCallback);
+
+  void ClearClipboardCache(int32_t aClipboardType);
+
+ private:
+  void RejectPendingAsyncSetDataRequestIfAny(int32_t aClipboardType);
+
+  class AsyncSetClipboardData final : public nsIAsyncSetClipboardData {
+   public:
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIASYNCSETCLIPBOARDDATA
+
+    AsyncSetClipboardData(int32_t aClipboardType, nsBaseClipboard* aClipboard,
+                          nsIAsyncClipboardRequestCallback* aCallback);
+
+   private:
+    virtual ~AsyncSetClipboardData() = default;
+    bool IsValid() const {
+      // If this request is no longer valid, the callback should be notified.
+      MOZ_ASSERT_IF(!mClipboard, !mCallback);
+      return !!mClipboard;
+    }
+    void MaybeNotifyCallback(nsresult aResult);
+
+    // The clipboard type defined in nsIClipboard.
+    int32_t mClipboardType;
+    // It is safe to use a raw pointer as it will be nullified (by calling
+    // NotifyCallback()) once nsBaseClipboard stops tracking us. This is
+    // also used to indicate whether this request is valid.
+    nsBaseClipboard* mClipboard;
+    // mCallback will be nullified once the callback is notified to ensure the
+    // callback is only notified once.
+    nsCOMPtr<nsIAsyncClipboardRequestCallback> mCallback;
+  };
+
+  class AsyncGetClipboardData final : public nsIAsyncGetClipboardData {
+   public:
+    AsyncGetClipboardData(
+        int32_t aClipboardType, int32_t aSequenceNumber,
+        nsTArray<nsCString>&& aFlavors, bool aFromCache,
+        nsBaseClipboard* aClipboard,
+        mozilla::dom::WindowContext* aRequestingWindowContext);
+
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIASYNCGETCLIPBOARDDATA
+
+   private:
+    virtual ~AsyncGetClipboardData() = default;
+    bool IsValid();
+
+    // The clipboard type defined in nsIClipboard.
+    const int32_t mClipboardType;
+    // The sequence number associated with the clipboard content for this
+    // request. If it doesn't match with the current sequence number in system
+    // clipboard, this request targets stale data and is deemed invalid.
+    const int32_t mSequenceNumber;
+    // List of available data types for clipboard content.
+    const nsTArray<nsCString> mFlavors;
+    // Data should be read from cache.
+    const bool mFromCache;
+    // This is also used to indicate whether this request is still valid.
+    RefPtr<nsBaseClipboard> mClipboard;
+    // The requesting window, which is used for Content Analysis purposes.
+    RefPtr<mozilla::dom::WindowContext> mRequestingWindowContext;
+  };
+
+  class ClipboardCache final {
+   public:
+    ~ClipboardCache() {
+      // In order to notify the old clipboard owner.
+      Clear();
+    }
+
+    /**
+     * Clear the cached transferable and notify the original clipboard owner
+     * that it has lost ownership.
+     */
+    void Clear();
+    void Update(nsITransferable* aTransferable,
+                nsIClipboardOwner* aClipboardOwner, int32_t aSequenceNumber) {
+      // Clear first to notify the old clipboard owner.
+      Clear();
+      mTransferable = aTransferable;
+      mClipboardOwner = aClipboardOwner;
+      mSequenceNumber = aSequenceNumber;
+    }
+    nsITransferable* GetTransferable() const { return mTransferable; }
+    nsIClipboardOwner* GetClipboardOwner() const { return mClipboardOwner; }
+    int32_t GetSequenceNumber() const { return mSequenceNumber; }
+    nsresult GetData(nsITransferable* aTransferable) const;
+
+   private:
+    nsCOMPtr<nsITransferable> mTransferable;
+    nsCOMPtr<nsIClipboardOwner> mClipboardOwner;
+    int32_t mSequenceNumber = -1;
+  };
+
+  void MaybeRetryGetAvailableFlavors(
+      const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard,
+      nsIAsyncClipboardGetCallback* aCallback, int32_t aRetryCount,
+      mozilla::dom::WindowContext* aRequestingWindowContext);
+
+  // Return clipboard cache if the cached data is valid, otherwise clear the
+  // cached data and returns null.
+  ClipboardCache* GetClipboardCacheIfValid(int32_t aClipboardType);
+
+  mozilla::Result<nsTArray<nsCString>, nsresult> GetFlavorsFromClipboardCache(
+      int32_t aClipboardType);
+  nsresult GetDataFromClipboardCache(nsITransferable* aTransferable,
+                                     int32_t aClipboardType);
+
+  void RequestUserConfirmation(int32_t aClipboardType,
+                               const nsTArray<nsCString>& aFlavorList,
+                               mozilla::dom::WindowContext* aWindowContext,
+                               nsIPrincipal* aRequestingPrincipal,
+                               nsIAsyncClipboardGetCallback* aCallback);
+
+  // Track the pending request for each clipboard type separately. And only need
+  // to track the latest request for each clipboard type as the prior pending
+  // request will be canceled when a new request is made.
+  RefPtr<AsyncSetClipboardData>
+      mPendingWriteRequests[nsIClipboard::kClipboardTypeCount];
+
+  mozilla::UniquePtr<ClipboardCache> mCaches[nsIClipboard::kClipboardTypeCount];
+  const mozilla::dom::ClipboardCapabilities mClipboardCaps;
+  bool mIgnoreEmptyNotification = false;
+};
+
+#endif  // nsBaseClipboard_h__
diff --git a/widget/nsBaseDragService.cpp b/widget/nsBaseDragService.cpp
new file mode 100644
index 0000000000..22ed844595
--- /dev/null
+++ b/widget/nsBaseDragService.cpp
@@ -0,0 +1,1044 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsBaseDragService.h"
+#include "nsITransferable.h"
+
+#include "nsArrayUtils.h"
+#include "nsITransferable.h"
+#include "nsSize.h"
+#include "nsXPCOM.h"
+#include "nsCOMPtr.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsIFrame.h"
+#include "nsFrameLoaderOwner.h"
+#include "nsIContent.h"
+#include "nsViewManager.h"
+#include "nsINode.h"
+#include "nsPresContext.h"
+#include "nsIImageLoadingContent.h"
+#include "imgIContainer.h"
+#include "imgIRequest.h"
+#include "ImageRegion.h"
+#include "nsQueryObject.h"
+#include "nsRegion.h"
+#include "nsXULPopupManager.h"
+#include "nsMenuPopupFrame.h"
+#include "nsTreeBodyFrame.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/SVGImageContext.h"
+#include "mozilla/TextControlElement.h"
+#include "mozilla/Unused.h"
+#include "mozilla/ViewportUtils.h"
+#include "mozilla/dom/BindingDeclarations.h"
+#include "mozilla/dom/DataTransferItemList.h"
+#include "mozilla/dom/DataTransfer.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/DocumentInlines.h"
+#include "mozilla/dom/DragEvent.h"
+#include "mozilla/dom/MouseEventBinding.h"
+#include "mozilla/dom/Selection.h"
+#include "mozilla/gfx/2D.h"
+#include "nsFrameLoader.h"
+#include "BrowserParent.h"
+#include "nsIMutableArray.h"
+#include "gfxContext.h"
+#include "gfxPlatform.h"
+#include "nscore.h"
+#include <algorithm>
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::gfx;
+using namespace mozilla::image;
+
+LazyLogModule sWidgetDragServiceLog("WidgetDragService");
+
+#define DRAGIMAGES_PREF "nglayout.enable_drag_images"
+
+nsBaseDragService::nsBaseDragService()
+    : mCanDrop(false),
+      mOnlyChromeDrop(false),
+      mDoingDrag(false),
+      mSessionIsSynthesizedForTests(false),
+      mIsDraggingTextInTextControl(false),
+      mEndingSession(false),
+      mHasImage(false),
+      mUserCancelled(false),
+      mDragEventDispatchedToChildProcess(false),
+      mDragAction(DRAGDROP_ACTION_NONE),
+      mDragActionFromChildProcess(DRAGDROP_ACTION_UNINITIALIZED),
+      mEffectAllowedForTests(DRAGDROP_ACTION_UNINITIALIZED),
+      mContentPolicyType(nsIContentPolicy::TYPE_OTHER),
+      mSuppressLevel(0),
+      mInputSource(MouseEvent_Binding::MOZ_SOURCE_MOUSE) {}
+
+nsBaseDragService::~nsBaseDragService() = default;
+
+NS_IMPL_ISUPPORTS(nsBaseDragService, nsIDragService, nsIDragSession)
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::SetCanDrop(bool aCanDrop) {
+  mCanDrop = aCanDrop;
+  return NS_OK;
+}
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::GetCanDrop(bool* aCanDrop) {
+  *aCanDrop = mCanDrop;
+  return NS_OK;
+}
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::SetOnlyChromeDrop(bool aOnlyChrome) {
+  mOnlyChromeDrop = aOnlyChrome;
+  return NS_OK;
+}
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::GetOnlyChromeDrop(bool* aOnlyChrome) {
+  *aOnlyChrome = mOnlyChromeDrop;
+  return NS_OK;
+}
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::SetDragAction(uint32_t anAction) {
+  mDragAction = anAction;
+  return NS_OK;
+}
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::GetDragAction(uint32_t* anAction) {
+  *anAction = mDragAction;
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+
+NS_IMETHODIMP
+nsBaseDragService::GetNumDropItems(uint32_t* aNumItems) {
+  *aNumItems = 0;
+  return NS_ERROR_FAILURE;
+}
+
+//
+// GetSourceWindowContext
+//
+// Returns the window context where the drag was initiated. This will be
+// nullptr if the drag began outside of our application.
+//
+NS_IMETHODIMP
+nsBaseDragService::GetSourceWindowContext(
+    WindowContext** aSourceWindowContext) {
+  *aSourceWindowContext = mSourceWindowContext.get();
+  NS_IF_ADDREF(*aSourceWindowContext);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::SetSourceWindowContext(WindowContext* aSourceWindowContext) {
+  // This should only be called in a child process.
+  MOZ_ASSERT(!XRE_IsParentProcess());
+  mSourceWindowContext = aSourceWindowContext;
+  return NS_OK;
+}
+
+//
+// GetSourceTopWindowContext
+//
+// Returns the top-level window context where the drag was initiated. This will
+// be nullptr if the drag began outside of our application.
+//
+NS_IMETHODIMP
+nsBaseDragService::GetSourceTopWindowContext(
+    WindowContext** aSourceTopWindowContext) {
+  *aSourceTopWindowContext = mSourceTopWindowContext.get();
+  NS_IF_ADDREF(*aSourceTopWindowContext);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::SetSourceTopWindowContext(
+    WindowContext* aSourceTopWindowContext) {
+  // This should only be called in a child process.
+  MOZ_ASSERT(!XRE_IsParentProcess());
+  mSourceTopWindowContext = aSourceTopWindowContext;
+  return NS_OK;
+}
+
+//
+// GetSourceNode
+//
+// Returns the DOM node where the drag was initiated. This will be
+// nullptr if the drag began outside of our application.
+//
+NS_IMETHODIMP
+nsBaseDragService::GetSourceNode(nsINode** aSourceNode) {
+  *aSourceNode = do_AddRef(mSourceNode).take();
+  return NS_OK;
+}
+
+void nsBaseDragService::UpdateSource(nsINode* aNewSourceNode,
+                                     Selection* aNewSelection) {
+  MOZ_ASSERT(mSourceNode);
+  MOZ_ASSERT(aNewSourceNode);
+  MOZ_ASSERT(mSourceNode->IsInNativeAnonymousSubtree() ||
+             aNewSourceNode->IsInNativeAnonymousSubtree());
+  MOZ_ASSERT(mSourceDocument == aNewSourceNode->OwnerDoc());
+  mSourceNode = aNewSourceNode;
+  // Don't set mSelection if the session was invoked without selection or
+  // making it becomes nullptr.  The latter occurs when the old frame is
+  // being destroyed.
+  if (mSelection && aNewSelection) {
+    // XXX If the dragging image is created once (e.g., at drag start), the
+    //     image won't be updated unless we notify `DrawDrag` callers.
+    //     However, it must be okay for now to keep using older image of
+    //     Selection.
+    mSelection = aNewSelection;
+  }
+}
+
+NS_IMETHODIMP
+nsBaseDragService::GetTriggeringPrincipal(nsIPrincipal** aPrincipal) {
+  NS_IF_ADDREF(*aPrincipal = mTriggeringPrincipal);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::SetTriggeringPrincipal(nsIPrincipal* aPrincipal) {
+  mTriggeringPrincipal = aPrincipal;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::GetCsp(nsIContentSecurityPolicy** aCsp) {
+  NS_IF_ADDREF(*aCsp = mCsp);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::SetCsp(nsIContentSecurityPolicy* aCsp) {
+  mCsp = aCsp;
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+
+NS_IMETHODIMP
+nsBaseDragService::GetData(nsITransferable* aTransferable,
+                           uint32_t aItemIndex) {
+  return NS_ERROR_FAILURE;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::IsDataFlavorSupported(const char* aDataFlavor,
+                                         bool* _retval) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::GetDataTransferXPCOM(DataTransfer** aDataTransfer) {
+  *aDataTransfer = mDataTransfer;
+  NS_IF_ADDREF(*aDataTransfer);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::SetDataTransferXPCOM(DataTransfer* aDataTransfer) {
+  NS_ENSURE_STATE(aDataTransfer);
+  mDataTransfer = aDataTransfer;
+  return NS_OK;
+}
+
+DataTransfer* nsBaseDragService::GetDataTransfer() { return mDataTransfer; }
+
+void nsBaseDragService::SetDataTransfer(DataTransfer* aDataTransfer) {
+  mDataTransfer = aDataTransfer;
+}
+
+bool nsBaseDragService::IsSynthesizedForTests() {
+  return mSessionIsSynthesizedForTests;
+}
+
+bool nsBaseDragService::IsDraggingTextInTextControl() {
+  return mIsDraggingTextInTextControl;
+}
+
+uint32_t nsBaseDragService::GetEffectAllowedForTests() {
+  MOZ_ASSERT(mSessionIsSynthesizedForTests);
+  return mEffectAllowedForTests;
+}
+
+NS_IMETHODIMP nsBaseDragService::SetDragEndPointForTests(int32_t aScreenX,
+                                                         int32_t aScreenY) {
+  MOZ_ASSERT(mDoingDrag);
+  MOZ_ASSERT(mSourceDocument);
+  MOZ_ASSERT(mSessionIsSynthesizedForTests);
+
+  if (!mDoingDrag || !mSourceDocument || !mSessionIsSynthesizedForTests) {
+    return NS_ERROR_FAILURE;
+  }
+  nsPresContext* pc = mSourceDocument->GetPresContext();
+  if (NS_WARN_IF(!pc)) {
+    return NS_ERROR_FAILURE;
+  }
+  auto p = LayoutDeviceIntPoint::Round(CSSIntPoint(aScreenX, aScreenY) *
+                                       pc->CSSToDevPixelScale());
+  // p is screen-relative, and we want them to be top-level-widget-relative.
+  if (nsCOMPtr<nsIWidget> widget = pc->GetRootWidget()) {
+    p -= widget->WidgetToScreenOffset();
+    p += widget->WidgetToTopLevelWidgetOffset();
+  }
+  SetDragEndPoint(p);
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::InvokeDragSession(
+    nsINode* aDOMNode, nsIPrincipal* aPrincipal, nsIContentSecurityPolicy* aCsp,
+    nsICookieJarSettings* aCookieJarSettings, nsIArray* aTransferableArray,
+    uint32_t aActionType,
+    nsContentPolicyType aContentPolicyType = nsIContentPolicy::TYPE_OTHER) {
+  AUTO_PROFILER_LABEL("nsBaseDragService::InvokeDragSession", OTHER);
+
+  NS_ENSURE_TRUE(aDOMNode, NS_ERROR_INVALID_ARG);
+  NS_ENSURE_TRUE(mSuppressLevel == 0, NS_ERROR_FAILURE);
+
+  // stash the document of the dom node
+  mSourceDocument = aDOMNode->OwnerDoc();
+  mTriggeringPrincipal = aPrincipal;
+  mCsp = aCsp;
+  mSourceNode = aDOMNode;
+  mIsDraggingTextInTextControl =
+      mSourceNode->IsInNativeAnonymousSubtree() &&
+      TextControlElement::FromNodeOrNull(
+          mSourceNode->GetClosestNativeAnonymousSubtreeRootParentOrHost());
+  mContentPolicyType = aContentPolicyType;
+  mEndDragPoint = LayoutDeviceIntPoint(0, 0);
+
+  // When the mouse goes down, the selection code starts a mouse
+  // capture. However, this gets in the way of determining drag
+  // feedback for things like trees because the event coordinates
+  // are in the wrong coord system, so turn off mouse capture.
+  PresShell::ClearMouseCapture();
+
+  if (mSessionIsSynthesizedForTests) {
+    mDoingDrag = true;
+    mDragAction = aActionType;
+    mEffectAllowedForTests = aActionType;
+    return NS_OK;
+  }
+
+  // If you're hitting this, a test is causing the browser to attempt to enter
+  // the drag-drop native nested event loop, which will put the browser in a
+  // state that won't run tests properly until there's manual intervention
+  // to exit the drag-drop loop (either by moving the mouse or hitting escape),
+  // which can't be done from script since we're in the nested loop.
+  //
+  // The best way to avoid this is to catch the dragstart event on the item
+  // being dragged, and then to call preventDefault() and stopPropagating() on
+  // it.
+  if (XRE_IsParentProcess()) {
+    MOZ_ASSERT(
+        !xpc::IsInAutomation(),
+        "About to start drag-drop native loop on which will prevent later "
+        "tests from running properly.");
+  }
+
+  uint32_t length = 0;
+  mozilla::Unused << aTransferableArray->GetLength(&length);
+  if (!length) {
+    nsCOMPtr<nsIMutableArray> mutableArray =
+        do_QueryInterface(aTransferableArray);
+    if (mutableArray) {
+      // In order to be able trigger dnd, we need to have some transferable
+      // object.
+      nsCOMPtr<nsITransferable> trans =
+          do_CreateInstance("@mozilla.org/widget/transferable;1");
+      trans->Init(nullptr);
+      trans->SetRequestingPrincipal(mSourceNode->NodePrincipal());
+      trans->SetContentPolicyType(mContentPolicyType);
+      trans->SetCookieJarSettings(aCookieJarSettings);
+      mutableArray->AppendElement(trans);
+    }
+  } else {
+    for (uint32_t i = 0; i < length; ++i) {
+      nsCOMPtr<nsITransferable> trans =
+          do_QueryElementAt(aTransferableArray, i);
+      if (trans) {
+        // Set the requestingPrincipal on the transferable.
+        trans->SetRequestingPrincipal(mSourceNode->NodePrincipal());
+        trans->SetContentPolicyType(mContentPolicyType);
+        trans->SetCookieJarSettings(aCookieJarSettings);
+      }
+    }
+  }
+
+  nsresult rv = InvokeDragSessionImpl(aTransferableArray, mRegion, aActionType);
+
+  if (NS_FAILED(rv)) {
+    // Set mDoingDrag so that EndDragSession cleans up and sends the dragend
+    // event after the aborted drag.
+    mDoingDrag = true;
+    EndDragSession(true, 0);
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::InvokeDragSessionWithImage(
+    nsINode* aDOMNode, nsIPrincipal* aPrincipal, nsIContentSecurityPolicy* aCsp,
+    nsICookieJarSettings* aCookieJarSettings, nsIArray* aTransferableArray,
+    uint32_t aActionType, nsINode* aImage, int32_t aImageX, int32_t aImageY,
+    DragEvent* aDragEvent, DataTransfer* aDataTransfer) {
+  NS_ENSURE_TRUE(aDragEvent, NS_ERROR_NULL_POINTER);
+  NS_ENSURE_TRUE(aDataTransfer, NS_ERROR_NULL_POINTER);
+  NS_ENSURE_TRUE(mSuppressLevel == 0, NS_ERROR_FAILURE);
+
+  mSessionIsSynthesizedForTests =
+      aDragEvent->WidgetEventPtr()->mFlags.mIsSynthesizedForTests;
+  mDataTransfer = aDataTransfer;
+  mSelection = nullptr;
+  mHasImage = true;
+  mDragPopup = nullptr;
+  mImage = aImage;
+  mImageOffset = CSSIntPoint(aImageX, aImageY);
+  mDragStartData = nullptr;
+  mSourceWindowContext =
+      aDOMNode ? aDOMNode->OwnerDoc()->GetWindowContext() : nullptr;
+  mSourceTopWindowContext =
+      mSourceWindowContext ? mSourceWindowContext->TopWindowContext() : nullptr;
+
+  mScreenPosition = aDragEvent->ScreenPoint(CallerType::System);
+  mInputSource = aDragEvent->InputSource();
+
+  // If dragging within a XUL tree and no custom drag image was
+  // set, the region argument to InvokeDragSessionWithImage needs
+  // to be set to the area encompassing the selected rows of the
+  // tree to ensure that the drag feedback gets clipped to those
+  // rows. For other content, region should be null.
+  mRegion = Nothing();
+  if (aDOMNode && aDOMNode->IsContent() && !aImage) {
+    if (aDOMNode->NodeInfo()->Equals(nsGkAtoms::treechildren,
+                                     kNameSpaceID_XUL)) {
+      nsTreeBodyFrame* treeBody =
+          do_QueryFrame(aDOMNode->AsContent()->GetPrimaryFrame());
+      if (treeBody) {
+        mRegion = treeBody->GetSelectionRegion();
+      }
+    }
+  }
+
+  nsresult rv = InvokeDragSession(
+      aDOMNode, aPrincipal, aCsp, aCookieJarSettings, aTransferableArray,
+      aActionType, nsIContentPolicy::TYPE_INTERNAL_IMAGE);
+  mRegion = Nothing();
+  return rv;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::InvokeDragSessionWithRemoteImage(
+    nsINode* aDOMNode, nsIPrincipal* aPrincipal, nsIContentSecurityPolicy* aCsp,
+    nsICookieJarSettings* aCookieJarSettings, nsIArray* aTransferableArray,
+    uint32_t aActionType, RemoteDragStartData* aDragStartData,
+    DragEvent* aDragEvent, DataTransfer* aDataTransfer) {
+  NS_ENSURE_TRUE(aDragEvent, NS_ERROR_NULL_POINTER);
+  NS_ENSURE_TRUE(aDataTransfer, NS_ERROR_NULL_POINTER);
+  NS_ENSURE_TRUE(mSuppressLevel == 0, NS_ERROR_FAILURE);
+
+  mSessionIsSynthesizedForTests =
+      aDragEvent->WidgetEventPtr()->mFlags.mIsSynthesizedForTests;
+  mDataTransfer = aDataTransfer;
+  mSelection = nullptr;
+  mHasImage = true;
+  mDragPopup = nullptr;
+  mImage = nullptr;
+  mDragStartData = aDragStartData;
+  mImageOffset = CSSIntPoint(0, 0);
+  mSourceWindowContext = mDragStartData->GetSourceWindowContext();
+  mSourceTopWindowContext = mDragStartData->GetSourceTopWindowContext();
+
+  mScreenPosition = aDragEvent->ScreenPoint(CallerType::System);
+  mInputSource = aDragEvent->InputSource();
+
+  nsresult rv = InvokeDragSession(
+      aDOMNode, aPrincipal, aCsp, aCookieJarSettings, aTransferableArray,
+      aActionType, nsIContentPolicy::TYPE_INTERNAL_IMAGE);
+  mRegion = Nothing();
+  return rv;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::InvokeDragSessionWithSelection(
+    Selection* aSelection, nsIPrincipal* aPrincipal,
+    nsIContentSecurityPolicy* aCsp, nsICookieJarSettings* aCookieJarSettings,
+    nsIArray* aTransferableArray, uint32_t aActionType, DragEvent* aDragEvent,
+    DataTransfer* aDataTransfer) {
+  NS_ENSURE_TRUE(aSelection, NS_ERROR_NULL_POINTER);
+  NS_ENSURE_TRUE(aDragEvent, NS_ERROR_NULL_POINTER);
+  NS_ENSURE_TRUE(mSuppressLevel == 0, NS_ERROR_FAILURE);
+
+  mSessionIsSynthesizedForTests =
+      aDragEvent->WidgetEventPtr()->mFlags.mIsSynthesizedForTests;
+  mDataTransfer = aDataTransfer;
+  mSelection = aSelection;
+  mHasImage = true;
+  mDragPopup = nullptr;
+  mImage = nullptr;
+  mImageOffset = CSSIntPoint();
+  mDragStartData = nullptr;
+  mRegion = Nothing();
+
+  mScreenPosition.x = aDragEvent->ScreenX(CallerType::System);
+  mScreenPosition.y = aDragEvent->ScreenY(CallerType::System);
+  mInputSource = aDragEvent->InputSource();
+
+  // just get the focused node from the selection
+  // XXXndeakin this should actually be the deepest node that contains both
+  // endpoints of the selection
+  nsCOMPtr<nsINode> node = aSelection->GetFocusNode();
+  mSourceWindowContext = node ? node->OwnerDoc()->GetWindowContext() : nullptr;
+  mSourceTopWindowContext =
+      mSourceWindowContext ? mSourceWindowContext->TopWindowContext() : nullptr;
+
+  return InvokeDragSession(node, aPrincipal, aCsp, aCookieJarSettings,
+                           aTransferableArray, aActionType,
+                           nsIContentPolicy::TYPE_OTHER);
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::GetCurrentSession(nsIDragSession** aSession) {
+  if (!aSession) return NS_ERROR_INVALID_ARG;
+
+  // "this" also implements a drag session, so say we are one but only
+  // if there is currently a drag going on.
+  if (!mSuppressLevel && mDoingDrag) {
+    *aSession = this;
+    NS_ADDREF(*aSession);  // addRef because we're a "getter"
+  } else
+    *aSession = nullptr;
+
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::StartDragSession() {
+  if (mDoingDrag) {
+    return NS_ERROR_FAILURE;
+  }
+  mDoingDrag = true;
+  // By default dispatch drop also to content.
+  mOnlyChromeDrop = false;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBaseDragService::StartDragSessionForTests(
+    uint32_t aAllowedEffect) {
+  if (NS_WARN_IF(NS_FAILED(StartDragSession()))) {
+    return NS_ERROR_FAILURE;
+  }
+  mDragAction = aAllowedEffect;
+  mEffectAllowedForTests = aAllowedEffect;
+  mSessionIsSynthesizedForTests = true;
+  return NS_OK;
+}
+
+void nsBaseDragService::OpenDragPopup() {
+  if (mDragPopup) {
+    nsXULPopupManager* pm = nsXULPopupManager::GetInstance();
+    if (pm) {
+      pm->ShowPopupAtScreen(mDragPopup, mScreenPosition.x - mImageOffset.x,
+                            mScreenPosition.y - mImageOffset.y, false, nullptr);
+    }
+  }
+}
+
+int32_t nsBaseDragService::TakeChildProcessDragAction() {
+  // If the last event was dispatched to the child process, use the drag action
+  // assigned from it instead and return it. DRAGDROP_ACTION_UNINITIALIZED is
+  // returned otherwise.
+  int32_t retval = DRAGDROP_ACTION_UNINITIALIZED;
+  if (TakeDragEventDispatchedToChildProcess() &&
+      mDragActionFromChildProcess != DRAGDROP_ACTION_UNINITIALIZED) {
+    retval = mDragActionFromChildProcess;
+  }
+
+  return retval;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsBaseDragService::EndDragSession(bool aDoneDrag, uint32_t aKeyModifiers) {
+  if (!mDoingDrag || mEndingSession) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mEndingSession = true;
+
+  if (aDoneDrag && !mSuppressLevel) {
+    FireDragEventAtSource(eDragEnd, aKeyModifiers);
+  }
+
+  if (mDragPopup) {
+    nsXULPopupManager* pm = nsXULPopupManager::GetInstance();
+    if (pm) {
+      pm->HidePopup(mDragPopup, {HidePopupOption::DeselectMenu});
+    }
+  }
+
+  uint32_t dropEffect = nsIDragService::DRAGDROP_ACTION_NONE;
+  if (mDataTransfer) {
+    dropEffect = mDataTransfer->DropEffectInt();
+  }
+
+  for (uint32_t i = 0; i < mChildProcesses.Length(); ++i) {
+    mozilla::Unused << mChildProcesses[i]->SendEndDragSession(
+        aDoneDrag, mUserCancelled, mEndDragPoint, aKeyModifiers, dropEffect);
+    // Continue sending input events with input priority when stopping the dnd
+    // session.
+    mChildProcesses[i]->SetInputPriorityEventEnabled(true);
+  }
+  mChildProcesses.Clear();
+
+  // mDataTransfer and the items it owns are going to die anyway, but we
+  // explicitly deref the contained data here so that we don't have to wait for
+  // CC to reclaim the memory.
+  if (XRE_IsParentProcess()) {
+    DiscardInternalTransferData();
+  }
+
+  mDoingDrag = false;
+  mSessionIsSynthesizedForTests = false;
+  mIsDraggingTextInTextControl = false;
+  mEffectAllowedForTests = nsIDragService::DRAGDROP_ACTION_UNINITIALIZED;
+  mEndingSession = false;
+  mCanDrop = false;
+
+  // release the source we've been holding on to.
+  mSourceDocument = nullptr;
+  mSourceNode = nullptr;
+  mSourceWindowContext = nullptr;
+  mSourceTopWindowContext = nullptr;
+  mTriggeringPrincipal = nullptr;
+  mCsp = nullptr;
+  mSelection = nullptr;
+  mDataTransfer = nullptr;
+  mHasImage = false;
+  mUserCancelled = false;
+  mDragPopup = nullptr;
+  mDragStartData = nullptr;
+  mImage = nullptr;
+  mImageOffset = CSSIntPoint();
+  mScreenPosition = CSSIntPoint();
+  mEndDragPoint = LayoutDeviceIntPoint(0, 0);
+  mInputSource = MouseEvent_Binding::MOZ_SOURCE_MOUSE;
+  mRegion = Nothing();
+
+  return NS_OK;
+}
+
+void nsBaseDragService::DiscardInternalTransferData() {
+  if (mDataTransfer && mSourceNode) {
+    MOZ_ASSERT(mDataTransfer);
+
+    DataTransferItemList* items = mDataTransfer->Items();
+    for (size_t i = 0; i < items->Length(); i++) {
+      bool found;
+      DataTransferItem* item = items->IndexedGetter(i, found);
+
+      // Non-OTHER items may still be needed by JS. Skip them.
+      if (!found || item->Kind() != DataTransferItem::KIND_OTHER) {
+        continue;
+      }
+
+      nsCOMPtr<nsIVariant> variant = item->DataNoSecurityCheck();
+      nsCOMPtr<nsIWritableVariant> writable = do_QueryInterface(variant);
+
+      if (writable) {
+        writable->SetAsEmpty();
+      }
+    }
+  }
+}
+
+NS_IMETHODIMP
+nsBaseDragService::FireDragEventAtSource(EventMessage aEventMessage,
+                                         uint32_t aKeyModifiers) {
+  if (!mSourceNode || !mSourceDocument || mSuppressLevel) {
+    return NS_OK;
+  }
+  RefPtr<PresShell> presShell = mSourceDocument->GetPresShell();
+  if (!presShell) {
+    return NS_OK;
+  }
+
+  RefPtr<nsPresContext> pc = presShell->GetPresContext();
+  nsCOMPtr<nsIWidget> widget = pc ? pc->GetRootWidget() : nullptr;
+
+  nsEventStatus status = nsEventStatus_eIgnore;
+  WidgetDragEvent event(true, aEventMessage, widget);
+  event.mFlags.mIsSynthesizedForTests = mSessionIsSynthesizedForTests;
+  event.mInputSource = mInputSource;
+  if (aEventMessage == eDragEnd) {
+    event.mRefPoint = mEndDragPoint;
+    if (widget) {
+      event.mRefPoint -= widget->WidgetToTopLevelWidgetOffset();
+    }
+    event.mUserCancelled = mUserCancelled;
+  }
+  event.mModifiers = aKeyModifiers;
+
+  // Most drag events aren't able to converted to MouseEvent except to
+  // eDragStart and eDragEnd.
+  if (widget && event.CanConvertToInputData()) {
+    // Send the drag event to APZ, which needs to know about them to be
+    // able to accurately detect the end of a drag gesture.
+    widget->DispatchEventToAPZOnly(&event);
+  }
+
+  nsCOMPtr<nsIContent> content = do_QueryInterface(mSourceNode);
+  return presShell->HandleDOMEventWithTarget(content, &event, &status);
+}
+
+/* This is used by Windows and Mac to update the position of a popup being
+ * used as a drag image during the drag. This isn't used on GTK as it manages
+ * the drag popup itself.
+ */
+NS_IMETHODIMP
+nsBaseDragService::DragMoved(int32_t aX, int32_t aY) {
+  if (mDragPopup) {
+    nsIFrame* frame = mDragPopup->GetPrimaryFrame();
+    if (frame && frame->IsMenuPopupFrame()) {
+      CSSIntPoint cssPos =
+          RoundedToInt(LayoutDeviceIntPoint(aX, aY) /
+                       frame->PresContext()->CSSToDevPixelScale()) -
+          mImageOffset;
+      static_cast<nsMenuPopupFrame*>(frame)->MoveTo(cssPos, true);
+    }
+  }
+
+  return NS_OK;
+}
+
+static PresShell* GetPresShellForContent(nsINode* aDOMNode) {
+  nsCOMPtr<nsIContent> content = do_QueryInterface(aDOMNode);
+  if (!content) return nullptr;
+
+  RefPtr<Document> document = content->GetComposedDoc();
+  if (document) {
+    document->FlushPendingNotifications(FlushType::Display);
+    return document->GetPresShell();
+  }
+
+  return nullptr;
+}
+
+nsresult nsBaseDragService::DrawDrag(nsINode* aDOMNode,
+                                     const Maybe<CSSIntRegion>& aRegion,
+                                     CSSIntPoint aScreenPosition,
+                                     LayoutDeviceIntRect* aScreenDragRect,
+                                     RefPtr<SourceSurface>* aSurface,
+                                     nsPresContext** aPresContext) {
+  *aSurface = nullptr;
+  *aPresContext = nullptr;
+
+  // use a default size, in case of an error.
+  aScreenDragRect->SetRect(aScreenPosition.x - mImageOffset.x,
+                           aScreenPosition.y - mImageOffset.y, 1, 1);
+
+  // if a drag image was specified, use that, otherwise, use the source node
+  nsCOMPtr<nsINode> dragNode = mImage ? mImage.get() : aDOMNode;
+
+  // get the presshell for the node being dragged. If the drag image is not in
+  // a document or has no frame, get the presshell from the source drag node
+  PresShell* presShell = GetPresShellForContent(dragNode);
+  if (!presShell && mImage) {
+    presShell = GetPresShellForContent(aDOMNode);
+  }
+  if (!presShell) {
+    return NS_ERROR_FAILURE;
+  }
+
+  *aPresContext = presShell->GetPresContext();
+
+  if (mDragStartData) {
+    if (mImage) {
+      // Just clear the surface if chrome has overridden it with an image.
+      *aSurface = nullptr;
+    } else {
+      *aSurface = mDragStartData->TakeVisualization(aScreenDragRect);
+    }
+
+    mDragStartData = nullptr;
+    return NS_OK;
+  }
+
+  // convert mouse position to dev pixels of the prescontext
+  const CSSIntPoint screenPosition = aScreenPosition - mImageOffset;
+  const auto screenPoint = LayoutDeviceIntPoint::Round(
+      screenPosition * (*aPresContext)->CSSToDevPixelScale());
+  aScreenDragRect->MoveTo(screenPoint.x, screenPoint.y);
+
+  // check if drag images are disabled
+  bool enableDragImages = Preferences::GetBool(DRAGIMAGES_PREF, true);
+
+  // didn't want an image, so just set the screen rectangle to the frame size
+  if (!enableDragImages || !mHasImage) {
+    // This holds a quantity in RelativeTo{presShell->GetRootFrame(),
+    // ViewportType::Layout} space.
+    nsRect presLayoutRect;
+    if (aRegion) {
+      // if a region was specified, set the screen rectangle to the area that
+      // the region occupies
+      presLayoutRect = ToAppUnits(aRegion->GetBounds(), AppUnitsPerCSSPixel());
+    } else {
+      // otherwise, there was no region so just set the rectangle to
+      // the size of the primary frame of the content.
+      nsCOMPtr<nsIContent> content = do_QueryInterface(dragNode);
+      if (nsIFrame* frame = content->GetPrimaryFrame()) {
+        presLayoutRect = frame->GetBoundingClientRect();
+      }
+    }
+
+    LayoutDeviceRect screenVisualRect = ViewportUtils::ToScreenRelativeVisual(
+        LayoutDeviceRect::FromAppUnits(presLayoutRect,
+                                       (*aPresContext)->AppUnitsPerDevPixel()),
+        *aPresContext);
+    aScreenDragRect->SizeTo(screenVisualRect.Width(),
+                            screenVisualRect.Height());
+    return NS_OK;
+  }
+
+  // draw the image for selections
+  if (mSelection) {
+    LayoutDeviceIntPoint pnt(aScreenDragRect->TopLeft());
+    *aSurface = presShell->RenderSelection(
+        mSelection, pnt, aScreenDragRect,
+        mImage ? RenderImageFlags::None : RenderImageFlags::AutoScale);
+    return NS_OK;
+  }
+
+  // if a custom image was specified, check if it is an image node and draw
+  // using the source rather than the displayed image. But if mImage isn't
+  // an image or canvas, fall through to RenderNode below.
+  if (mImage) {
+    nsCOMPtr<nsIContent> content = do_QueryInterface(dragNode);
+    HTMLCanvasElement* canvas = HTMLCanvasElement::FromNodeOrNull(content);
+    if (canvas) {
+      return DrawDragForImage(*aPresContext, nullptr, canvas, aScreenDragRect,
+                              aSurface);
+    }
+
+    nsCOMPtr<nsIImageLoadingContent> imageLoader = do_QueryInterface(dragNode);
+    // for image nodes, create the drag image from the actual image data
+    if (imageLoader) {
+      return DrawDragForImage(*aPresContext, imageLoader, nullptr,
+                              aScreenDragRect, aSurface);
+    }
+
+    // If the image is a popup, use that as the image. This allows custom drag
+    // images that can change during the drag, but means that any platform
+    // default image handling won't occur.
+    // XXXndeakin this should be chrome-only
+
+    nsIFrame* frame = content->GetPrimaryFrame();
+    if (frame && frame->IsMenuPopupFrame()) {
+      mDragPopup = content->AsElement();
+    }
+  }
+
+  if (!mDragPopup) {
+    // otherwise, just draw the node
+    RenderImageFlags renderFlags =
+        mImage ? RenderImageFlags::None : RenderImageFlags::AutoScale;
+    if (renderFlags != RenderImageFlags::None) {
+      // check if the dragged node itself is an img element
+      if (dragNode->NodeName().LowerCaseEqualsLiteral("img")) {
+        renderFlags = renderFlags | RenderImageFlags::IsImage;
+      } else {
+        nsINodeList* childList = dragNode->ChildNodes();
+        uint32_t length = childList->Length();
+        // check every childnode for being an img element
+        // XXXbz why don't we need to check descendants recursively?
+        for (uint32_t count = 0; count < length; ++count) {
+          if (childList->Item(count)->NodeName().LowerCaseEqualsLiteral(
+                  "img")) {
+            // if the dragnode contains an image, set RenderImageFlags::IsImage
+            // flag
+            renderFlags = renderFlags | RenderImageFlags::IsImage;
+            break;
+          }
+        }
+      }
+    }
+    LayoutDeviceIntPoint pnt(aScreenDragRect->TopLeft());
+    *aSurface = presShell->RenderNode(dragNode, aRegion, pnt, aScreenDragRect,
+                                      renderFlags);
+  }
+
+  // If an image was specified, reset the position from the offset that was
+  // supplied.
+  if (mImage) {
+    aScreenDragRect->MoveTo(screenPoint.x, screenPoint.y);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsBaseDragService::DrawDragForImage(
+    nsPresContext* aPresContext, nsIImageLoadingContent* aImageLoader,
+    HTMLCanvasElement* aCanvas, LayoutDeviceIntRect* aScreenDragRect,
+    RefPtr<SourceSurface>* aSurface) {
+  nsCOMPtr<imgIContainer> imgContainer;
+  if (aImageLoader) {
+    nsCOMPtr<imgIRequest> imgRequest;
+    nsresult rv = aImageLoader->GetRequest(
+        nsIImageLoadingContent::CURRENT_REQUEST, getter_AddRefs(imgRequest));
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!imgRequest) return NS_ERROR_NOT_AVAILABLE;
+
+    rv = imgRequest->GetImage(getter_AddRefs(imgContainer));
+    NS_ENSURE_SUCCESS(rv, rv);
+    if (!imgContainer) return NS_ERROR_NOT_AVAILABLE;
+
+    // use the size of the image as the size of the drag image
+    int32_t imageWidth, imageHeight;
+    rv = imgContainer->GetWidth(&imageWidth);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = imgContainer->GetHeight(&imageHeight);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    aScreenDragRect->SizeTo(aPresContext->CSSPixelsToDevPixels(imageWidth),
+                            aPresContext->CSSPixelsToDevPixels(imageHeight));
+  } else {
+    // XXX The canvas size should be converted to dev pixels.
+    NS_ASSERTION(aCanvas, "both image and canvas are null");
+    nsIntSize sz = aCanvas->GetSize();
+    aScreenDragRect->SizeTo(sz.width, sz.height);
+  }
+
+  nsIntSize destSize;
+  destSize.width = aScreenDragRect->Width();
+  destSize.height = aScreenDragRect->Height();
+  if (destSize.width == 0 || destSize.height == 0) return NS_ERROR_FAILURE;
+
+  nsresult result = NS_OK;
+  if (aImageLoader) {
+    RefPtr<DrawTarget> dt =
+        gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(
+            destSize, SurfaceFormat::B8G8R8A8);
+    if (!dt || !dt->IsValid()) return NS_ERROR_FAILURE;
+
+    gfxContext ctx(dt);
+
+    ImgDrawResult res = imgContainer->Draw(
+        &ctx, destSize, ImageRegion::Create(destSize),
+        imgIContainer::FRAME_CURRENT, SamplingFilter::GOOD, SVGImageContext(),
+        imgIContainer::FLAG_SYNC_DECODE, 1.0);
+    if (res == ImgDrawResult::BAD_IMAGE || res == ImgDrawResult::BAD_ARGS ||
+        res == ImgDrawResult::NOT_SUPPORTED) {
+      return NS_ERROR_FAILURE;
+    }
+    *aSurface = dt->Snapshot();
+  } else {
+    *aSurface = aCanvas->GetSurfaceSnapshot();
+  }
+
+  return result;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::Suppress() {
+  EndDragSession(false, 0);
+  ++mSuppressLevel;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::Unsuppress() {
+  --mSuppressLevel;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::UserCancelled() {
+  mUserCancelled = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::UpdateDragEffect() {
+  mDragActionFromChildProcess = mDragAction;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::UpdateDragImage(nsINode* aImage, int32_t aImageX,
+                                   int32_t aImageY) {
+  // Don't change the image if this is a drag from another source or if there
+  // is a drag popup.
+  if (!mSourceNode || mDragPopup) return NS_OK;
+
+  mImage = aImage;
+  mImageOffset = CSSIntPoint(aImageX, aImageY);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::DragEventDispatchedToChildProcess() {
+  mDragEventDispatchedToChildProcess = true;
+  return NS_OK;
+}
+
+bool nsBaseDragService::MaybeAddChildProcess(
+    mozilla::dom::ContentParent* aChild) {
+  if (!mChildProcesses.Contains(aChild)) {
+    mChildProcesses.AppendElement(aChild);
+    return true;
+  }
+  return false;
+}
+
+bool nsBaseDragService::RemoveAllChildProcesses() {
+  for (uint32_t c = 0; c < mChildProcesses.Length(); c++) {
+    mozilla::Unused << mChildProcesses[c]->SendEndDragSession(
+        true, false, LayoutDeviceIntPoint(), 0,
+        nsIDragService::DRAGDROP_ACTION_NONE);
+  }
+  mChildProcesses.Clear();
+  return true;
+}
+
+bool nsBaseDragService::MustUpdateDataTransfer(EventMessage aMessage) {
+  return false;
+}
+
+NS_IMETHODIMP
+nsBaseDragService::MaybeEditorDeletedSourceNode(Element* aEditingHost) {
+  // If builtin editor of Blink and WebKit deletes the source node,they retarget
+  // the source node to the editing host.
+  // https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/renderer/core/page/drag_controller.cc;l=724;drc=d9ba13b8cd8ac0faed7afc3d1f7e4b67ebac2a0b
+  // That allows editor apps listens to "dragend" event in editing host or its
+  // ancestors.  Therefore, we should follow them for compatibility.
+  if (mSourceNode && !mSourceNode->IsInComposedDoc()) {
+    mSourceNode = aEditingHost;
+  }
+  return NS_OK;
+}
diff --git a/widget/nsBaseDragService.h b/widget/nsBaseDragService.h
new file mode 100644
index 0000000000..7e76a23604
--- /dev/null
+++ b/widget/nsBaseDragService.h
@@ -0,0 +1,221 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsBaseDragService_h__
+#define nsBaseDragService_h__
+
+#include "nsIDragService.h"
+#include "nsIDragSession.h"
+#include "nsCOMPtr.h"
+#include "nsRect.h"
+#include "nsPoint.h"
+#include "nsString.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/HTMLCanvasElement.h"
+#include "mozilla/dom/RemoteDragStartData.h"
+#include "mozilla/Logging.h"
+#include "nsTArray.h"
+#include "nsRegion.h"
+#include "Units.h"
+
+extern mozilla::LazyLogModule sWidgetDragServiceLog;
+#define MOZ_DRAGSERVICE_LOG(...) \
+  MOZ_LOG(sWidgetDragServiceLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+#define MOZ_DRAGSERVICE_LOG_ENABLED() \
+  MOZ_LOG_TEST(sWidgetDragServiceLog, mozilla::LogLevel::Debug)
+
+// translucency level for drag images
+#define DRAG_TRANSLUCENCY 0.65
+
+class nsIContent;
+
+class nsINode;
+class nsPresContext;
+class nsIImageLoadingContent;
+
+namespace mozilla {
+namespace gfx {
+class SourceSurface;
+}  // namespace gfx
+
+namespace dom {
+class DataTransfer;
+class Selection;
+}  // namespace dom
+}  // namespace mozilla
+
+/**
+ * XP DragService wrapper base class
+ */
+
+class nsBaseDragService : public nsIDragService, public nsIDragSession {
+ public:
+  typedef mozilla::gfx::SourceSurface SourceSurface;
+
+  nsBaseDragService();
+
+  // nsISupports
+  NS_DECL_ISUPPORTS
+
+  // nsIDragSession and nsIDragService
+  NS_DECL_NSIDRAGSERVICE
+  NS_DECL_NSIDRAGSESSION
+
+  void SetDragEndPoint(nsIntPoint aEndDragPoint) {
+    mEndDragPoint =
+        mozilla::LayoutDeviceIntPoint::FromUnknownPoint(aEndDragPoint);
+  }
+  void SetDragEndPoint(mozilla::LayoutDeviceIntPoint aEndDragPoint) {
+    mEndDragPoint = aEndDragPoint;
+  }
+
+  uint16_t GetInputSource() { return mInputSource; }
+
+  int32_t TakeChildProcessDragAction();
+
+ protected:
+  virtual ~nsBaseDragService();
+
+  /**
+   * Called from nsBaseDragService to initiate a platform drag from a source
+   * in this process.  This is expected to ensure that StartDragSession() and
+   * EndDragSession() get called if the platform drag is successfully invoked.
+   */
+  MOZ_CAN_RUN_SCRIPT virtual nsresult InvokeDragSessionImpl(
+      nsIArray* aTransferableArray,
+      const mozilla::Maybe<mozilla::CSSIntRegion>& aRegion,
+      uint32_t aActionType) = 0;
+
+  /**
+   * Draw the drag image, if any, to a surface and return it. The drag image
+   * is constructed from mImage if specified, or aDOMNode if mImage is null.
+   *
+   * aRegion may be used to draw only a subset of the element. This region
+   * should be supplied using x and y coordinates measured in css pixels
+   * that are relative to the upper-left corner of the window.
+   *
+   * aScreenPosition should be the screen coordinates of the mouse click
+   * for the drag. These are in CSS pixels.
+   *
+   * On return, aScreenDragRect will contain the screen coordinates of the
+   * area being dragged. This is used by the platform-specific part of the
+   * drag service to determine the drag feedback. This rect will be in the
+   * device pixels of the presContext.
+   *
+   * If there is no drag image, the returned surface will be null, but
+   * aScreenDragRect will still be set to the drag area.
+   *
+   * aPresContext will be set to the nsPresContext used determined from
+   * whichever of mImage or aDOMNode is used.
+   */
+  nsresult DrawDrag(nsINode* aDOMNode,
+                    const mozilla::Maybe<mozilla::CSSIntRegion>& aRegion,
+                    mozilla::CSSIntPoint aScreenPosition,
+                    mozilla::LayoutDeviceIntRect* aScreenDragRect,
+                    RefPtr<SourceSurface>* aSurface,
+                    nsPresContext** aPresContext);
+
+  /**
+   * Draw a drag image for an image node specified by aImageLoader or aCanvas.
+   * This is called by DrawDrag.
+   */
+  nsresult DrawDragForImage(nsPresContext* aPresContext,
+                            nsIImageLoadingContent* aImageLoader,
+                            mozilla::dom::HTMLCanvasElement* aCanvas,
+                            mozilla::LayoutDeviceIntRect* aScreenDragRect,
+                            RefPtr<SourceSurface>* aSurface);
+
+  /**
+   * If the drag image is a popup, open the popup when the drag begins.
+   */
+  void OpenDragPopup();
+
+  /**
+   * Free resources contained in DataTransferItems that aren't needed by JS.
+   */
+  void DiscardInternalTransferData();
+
+  // Returns true if a drag event was dispatched to a child process after
+  // the previous TakeDragEventDispatchedToChildProcess() call.
+  bool TakeDragEventDispatchedToChildProcess() {
+    bool retval = mDragEventDispatchedToChildProcess;
+    mDragEventDispatchedToChildProcess = false;
+    return retval;
+  }
+
+  bool mCanDrop;
+  bool mOnlyChromeDrop;
+  bool mDoingDrag;
+  bool mSessionIsSynthesizedForTests;
+  bool mIsDraggingTextInTextControl;
+
+  // true if in EndDragSession
+  bool mEndingSession;
+  // true if mImage should be used to set a drag image
+  bool mHasImage;
+  // true if the user cancelled the drag operation
+  bool mUserCancelled;
+
+  bool mDragEventDispatchedToChildProcess;
+
+  uint32_t mDragAction;
+  uint32_t mDragActionFromChildProcess;
+
+  // mEffectAllowedForTests stores allowed effects at invoking the drag
+  // for tests.
+  uint32_t mEffectAllowedForTests;
+
+  nsCOMPtr<nsINode> mSourceNode;
+  nsCOMPtr<nsIPrincipal> mTriggeringPrincipal;
+  nsCOMPtr<nsIContentSecurityPolicy> mCsp;
+
+  // the document at the drag source. will be null if it came from outside the
+  // app.
+  RefPtr<mozilla::dom::Document> mSourceDocument;
+
+  RefPtr<mozilla::dom::WindowContext> mSourceWindowContext;
+  RefPtr<mozilla::dom::WindowContext> mSourceTopWindowContext;
+
+  // the contentpolicy type passed to the channel when initiating the drag
+  // session
+  nsContentPolicyType mContentPolicyType;
+
+  RefPtr<mozilla::dom::DataTransfer> mDataTransfer;
+
+  // used to determine the image to appear on the cursor while dragging
+  nsCOMPtr<nsINode> mImage;
+  // offset of cursor within the image
+  mozilla::CSSIntPoint mImageOffset;
+
+  // set if a selection is being dragged
+  RefPtr<mozilla::dom::Selection> mSelection;
+
+  // remote drag data
+  RefPtr<mozilla::dom::RemoteDragStartData> mDragStartData;
+
+  // set if the image in mImage is a popup. If this case, the popup will be
+  // opened and moved instead of using a drag image.
+  nsCOMPtr<mozilla::dom::Element> mDragPopup;
+
+  // the screen position where drag gesture occurred, used for positioning the
+  // drag image.
+  mozilla::CSSIntPoint mScreenPosition;
+
+  // The position relative to the top level widget where the drag ended.
+  mozilla::LayoutDeviceIntPoint mEndDragPoint;
+
+  uint32_t mSuppressLevel;
+
+  // The input source of the drag event. Possible values are from MouseEvent.
+  uint16_t mInputSource;
+
+  nsTArray<RefPtr<mozilla::dom::ContentParent>> mChildProcesses;
+
+  // Sub-region for tree-selections.
+  mozilla::Maybe<mozilla::CSSIntRegion> mRegion;
+};
+
+#endif  // nsBaseDragService_h__
diff --git a/widget/nsBaseFilePicker.cpp b/widget/nsBaseFilePicker.cpp
new file mode 100644
index 0000000000..53be3d80b7
--- /dev/null
+++ b/widget/nsBaseFilePicker.cpp
@@ -0,0 +1,496 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsCOMPtr.h"
+#include "nsPIDOMWindow.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsIWidget.h"
+
+#include "nsIStringBundle.h"
+#include "nsString.h"
+#include "nsCOMArray.h"
+#include "nsIFile.h"
+#include "nsEnumeratorUtils.h"
+#include "mozilla/dom/Directory.h"
+#include "mozilla/dom/File.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/Components.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "WidgetUtils.h"
+#include "nsSimpleEnumerator.h"
+#include "nsThreadUtils.h"
+#include "nsContentUtils.h"
+
+#include "nsBaseFilePicker.h"
+
+using namespace mozilla::widget;
+using namespace mozilla::dom;
+using mozilla::ErrorResult;
+
+#define FILEPICKER_TITLES "chrome://global/locale/filepicker.properties"
+#define FILEPICKER_FILTERS "chrome://global/content/filepicker.properties"
+
+namespace {
+
+nsresult LocalFileToDirectoryOrBlob(nsPIDOMWindowInner* aWindow,
+                                    bool aIsDirectory, nsIFile* aFile,
+                                    nsISupports** aResult) {
+  MOZ_ASSERT(aWindow);
+
+  if (aIsDirectory) {
+#ifdef DEBUG
+    bool isDir;
+    aFile->IsDirectory(&isDir);
+    MOZ_ASSERT(isDir);
+#endif
+
+    RefPtr<Directory> directory = Directory::Create(aWindow->AsGlobal(), aFile);
+    MOZ_ASSERT(directory);
+
+    directory.forget(aResult);
+    return NS_OK;
+  }
+
+  RefPtr<File> file = File::CreateFromFile(aWindow->AsGlobal(), aFile);
+  if (NS_WARN_IF(!file)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  file.forget(aResult);
+  return NS_OK;
+}
+
+}  // anonymous namespace
+
+#ifndef XP_WIN
+/**
+ * A runnable to dispatch from the main thread to the main thread to display
+ * the file picker while letting the showAsync method return right away.
+ *
+ * Not needed on Windows, where nsFilePicker::Open() is fully async.
+ */
+class nsBaseFilePicker::AsyncShowFilePicker : public mozilla::Runnable {
+ public:
+  AsyncShowFilePicker(nsBaseFilePicker* aFilePicker,
+                      nsIFilePickerShownCallback* aCallback)
+      : mozilla::Runnable("AsyncShowFilePicker"),
+        mFilePicker(aFilePicker),
+        mCallback(aCallback) {}
+
+  NS_IMETHOD Run() override {
+    NS_ASSERTION(NS_IsMainThread(),
+                 "AsyncShowFilePicker should be on the main thread!");
+
+    // It's possible that some widget implementations require GUI operations
+    // to be on the main thread, so that's why we're not dispatching to another
+    // thread and calling back to the main after it's done.
+    nsIFilePicker::ResultCode result = nsIFilePicker::returnCancel;
+    nsresult rv = mFilePicker->Show(&result);
+    if (NS_FAILED(rv)) {
+      NS_ERROR("FilePicker's Show() implementation failed!");
+    }
+
+    if (mCallback) {
+      mCallback->Done(result);
+    }
+    return NS_OK;
+  }
+
+ private:
+  RefPtr<nsBaseFilePicker> mFilePicker;
+  RefPtr<nsIFilePickerShownCallback> mCallback;
+};
+#endif
+
+class nsBaseFilePickerEnumerator : public nsSimpleEnumerator {
+ public:
+  nsBaseFilePickerEnumerator(nsPIDOMWindowOuter* aParent,
+                             nsISimpleEnumerator* iterator,
+                             nsIFilePicker::Mode aMode)
+      : mIterator(iterator),
+        mParent(aParent->GetCurrentInnerWindow()),
+        mMode(aMode) {}
+
+  const nsID& DefaultInterface() override { return NS_GET_IID(nsIFile); }
+
+  NS_IMETHOD
+  GetNext(nsISupports** aResult) override {
+    nsCOMPtr<nsISupports> tmp;
+    nsresult rv = mIterator->GetNext(getter_AddRefs(tmp));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    if (!tmp) {
+      return NS_OK;
+    }
+
+    nsCOMPtr<nsIFile> localFile = do_QueryInterface(tmp);
+    if (!localFile) {
+      return NS_ERROR_FAILURE;
+    }
+
+    if (!mParent) {
+      return NS_ERROR_FAILURE;
+    }
+
+    return LocalFileToDirectoryOrBlob(
+        mParent, mMode == nsIFilePicker::modeGetFolder, localFile, aResult);
+  }
+
+  NS_IMETHOD
+  HasMoreElements(bool* aResult) override {
+    return mIterator->HasMoreElements(aResult);
+  }
+
+ private:
+  nsCOMPtr<nsISimpleEnumerator> mIterator;
+  nsCOMPtr<nsPIDOMWindowInner> mParent;
+  nsIFilePicker::Mode mMode;
+};
+
+nsBaseFilePicker::nsBaseFilePicker()
+    : mAddToRecentDocs(true), mMode(nsIFilePicker::modeOpen) {}
+
+nsBaseFilePicker::~nsBaseFilePicker() = default;
+
+NS_IMETHODIMP nsBaseFilePicker::Init(
+    mozIDOMWindowProxy* aParent, const nsAString& aTitle,
+    nsIFilePicker::Mode aMode,
+    mozilla::dom::BrowsingContext* aBrowsingContext) {
+  MOZ_ASSERT(aParent,
+             "Null parent passed to filepicker, no file "
+             "picker for you!");
+
+  mParent = nsPIDOMWindowOuter::From(aParent);
+
+  nsCOMPtr<nsIWidget> widget = WidgetUtils::DOMWindowToWidget(mParent);
+  NS_ENSURE_TRUE(widget, NS_ERROR_FAILURE);
+
+  mBrowsingContext = aBrowsingContext;
+  mMode = aMode;
+  InitNative(widget, aTitle);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseFilePicker::IsModeSupported(nsIFilePicker::Mode aMode, JSContext* aCx,
+                                  Promise** aPromise) {
+  MOZ_ASSERT(aCx);
+  MOZ_ASSERT(aPromise);
+
+  nsIGlobalObject* globalObject = xpc::CurrentNativeGlobal(aCx);
+  if (NS_WARN_IF(!globalObject)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  ErrorResult result;
+  RefPtr<Promise> promise = Promise::Create(globalObject, result);
+  if (NS_WARN_IF(result.Failed())) {
+    return result.StealNSResult();
+  }
+
+  promise->MaybeResolve(true);
+  promise.forget(aPromise);
+
+  return NS_OK;
+}
+
+#ifndef XP_WIN
+NS_IMETHODIMP
+nsBaseFilePicker::Open(nsIFilePickerShownCallback* aCallback) {
+  if (MaybeBlockFilePicker(aCallback)) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIRunnable> filePickerEvent =
+      new AsyncShowFilePicker(this, aCallback);
+  return NS_DispatchToMainThread(filePickerEvent);
+}
+#endif
+
+NS_IMETHODIMP
+nsBaseFilePicker::Close() {
+  NS_WARNING("Unimplemented nsFilePicker::Close");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseFilePicker::AppendFilters(int32_t aFilterMask) {
+  nsCOMPtr<nsIStringBundleService> stringService =
+      mozilla::components::StringBundle::Service();
+  if (!stringService) return NS_ERROR_FAILURE;
+
+  nsCOMPtr<nsIStringBundle> titleBundle, filterBundle;
+
+  nsresult rv = stringService->CreateBundle(FILEPICKER_TITLES,
+                                            getter_AddRefs(titleBundle));
+  if (NS_FAILED(rv)) return NS_ERROR_FAILURE;
+
+  rv = stringService->CreateBundle(FILEPICKER_FILTERS,
+                                   getter_AddRefs(filterBundle));
+  if (NS_FAILED(rv)) return NS_ERROR_FAILURE;
+
+  nsAutoString title;
+  nsAutoString filter;
+
+  if (aFilterMask & filterAll) {
+    titleBundle->GetStringFromName("allTitle", title);
+    filterBundle->GetStringFromName("allFilter", filter);
+    AppendFilter(title, filter);
+  }
+  if (aFilterMask & filterHTML) {
+    titleBundle->GetStringFromName("htmlTitle", title);
+    filterBundle->GetStringFromName("htmlFilter", filter);
+    AppendFilter(title, filter);
+  }
+  if (aFilterMask & filterText) {
+    titleBundle->GetStringFromName("textTitle", title);
+    filterBundle->GetStringFromName("textFilter", filter);
+    AppendFilter(title, filter);
+  }
+  if (aFilterMask & filterImages) {
+    titleBundle->GetStringFromName("imageTitle", title);
+    filterBundle->GetStringFromName("imageFilter", filter);
+    AppendFilter(title, filter);
+  }
+  if (aFilterMask & filterAudio) {
+    titleBundle->GetStringFromName("audioTitle", title);
+    filterBundle->GetStringFromName("audioFilter", filter);
+    AppendFilter(title, filter);
+  }
+  if (aFilterMask & filterVideo) {
+    titleBundle->GetStringFromName("videoTitle", title);
+    filterBundle->GetStringFromName("videoFilter", filter);
+    AppendFilter(title, filter);
+  }
+  if (aFilterMask & filterXML) {
+    titleBundle->GetStringFromName("xmlTitle", title);
+    filterBundle->GetStringFromName("xmlFilter", filter);
+    AppendFilter(title, filter);
+  }
+  if (aFilterMask & filterXUL) {
+    titleBundle->GetStringFromName("xulTitle", title);
+    filterBundle->GetStringFromName("xulFilter", filter);
+    AppendFilter(title, filter);
+  }
+  if (aFilterMask & filterApps) {
+    titleBundle->GetStringFromName("appsTitle", title);
+    // Pass the magic string "..apps" to the platform filepicker, which it
+    // should recognize and do the correct platform behavior for.
+    AppendFilter(title, u"..apps"_ns);
+  }
+  if (aFilterMask & filterPDF) {
+    titleBundle->GetStringFromName("pdfTitle", title);
+    filterBundle->GetStringFromName("pdfFilter", filter);
+    AppendFilter(title, filter);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBaseFilePicker::AppendRawFilter(const nsAString& aFilter) {
+  mRawFilters.AppendElement(aFilter);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBaseFilePicker::GetCapture(
+    nsIFilePicker::CaptureTarget* aCapture) {
+  *aCapture = nsIFilePicker::CaptureTarget::captureNone;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBaseFilePicker::SetCapture(
+    nsIFilePicker::CaptureTarget aCapture) {
+  return NS_OK;
+}
+
+// Set the filter index
+NS_IMETHODIMP nsBaseFilePicker::GetFilterIndex(int32_t* aFilterIndex) {
+  *aFilterIndex = 0;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBaseFilePicker::SetFilterIndex(int32_t aFilterIndex) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBaseFilePicker::GetFiles(nsISimpleEnumerator** aFiles) {
+  NS_ENSURE_ARG_POINTER(aFiles);
+  nsCOMArray<nsIFile> files;
+  nsresult rv;
+
+  // if we get into the base class, the platform
+  // doesn't implement GetFiles() yet.
+  // so we fake it.
+  nsCOMPtr<nsIFile> file;
+  rv = GetFile(getter_AddRefs(file));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  files.AppendObject(file);
+
+  return NS_NewArrayEnumerator(aFiles, files, NS_GET_IID(nsIFile));
+}
+
+// Set the display directory
+NS_IMETHODIMP nsBaseFilePicker::SetDisplayDirectory(nsIFile* aDirectory) {
+  // if displaySpecialDirectory has been previously called, let's abort this
+  // operation.
+  if (!mDisplaySpecialDirectory.IsEmpty()) {
+    return NS_OK;
+  }
+
+  if (!aDirectory) {
+    mDisplayDirectory = nullptr;
+    return NS_OK;
+  }
+  nsCOMPtr<nsIFile> directory;
+  nsresult rv = aDirectory->Clone(getter_AddRefs(directory));
+  if (NS_FAILED(rv)) return rv;
+  mDisplayDirectory = directory;
+  return NS_OK;
+}
+
+// Get the display directory
+NS_IMETHODIMP nsBaseFilePicker::GetDisplayDirectory(nsIFile** aDirectory) {
+  *aDirectory = nullptr;
+
+  // if displaySpecialDirectory has been previously called, let's abort this
+  // operation.
+  if (!mDisplaySpecialDirectory.IsEmpty()) {
+    return NS_OK;
+  }
+
+  if (!mDisplayDirectory) return NS_OK;
+  nsCOMPtr<nsIFile> directory;
+  nsresult rv = mDisplayDirectory->Clone(getter_AddRefs(directory));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  directory.forget(aDirectory);
+  return NS_OK;
+}
+
+// Set the display special directory
+NS_IMETHODIMP nsBaseFilePicker::SetDisplaySpecialDirectory(
+    const nsAString& aDirectory) {
+  // if displayDirectory has been previously called, let's abort this operation.
+  if (mDisplayDirectory && mDisplaySpecialDirectory.IsEmpty()) {
+    return NS_OK;
+  }
+
+  mDisplaySpecialDirectory = aDirectory;
+  if (mDisplaySpecialDirectory.IsEmpty()) {
+    mDisplayDirectory = nullptr;
+    return NS_OK;
+  }
+
+  return ResolveSpecialDirectory(aDirectory);
+}
+
+bool nsBaseFilePicker::MaybeBlockFilePicker(
+    nsIFilePickerShownCallback* aCallback) {
+  if (!mozilla::StaticPrefs::widget_disable_file_pickers()) {
+    return false;
+  }
+
+  if (aCallback) {
+    // File pickers are disabled, so we answer the callback with returnCancel.
+    aCallback->Done(nsIFilePicker::returnCancel);
+  }
+  if (mBrowsingContext) {
+    RefPtr<Element> topFrameElement = mBrowsingContext->GetTopFrameElement();
+    if (topFrameElement) {
+      // Dispatch an event that the frontend may use.
+      nsContentUtils::DispatchEventOnlyToChrome(
+          topFrameElement->OwnerDoc(), topFrameElement, u"FilePickerBlocked"_ns,
+          mozilla::CanBubble::eYes, mozilla::Cancelable::eNo);
+    }
+  }
+
+  return true;
+}
+
+nsresult nsBaseFilePicker::ResolveSpecialDirectory(
+    const nsAString& aSpecialDirectory) {
+  // Only perform special-directory name resolution in the parent process.
+  // (Subclasses of `nsBaseFilePicker` used in other processes must override
+  // this function.)
+  MOZ_ASSERT(XRE_IsParentProcess());
+  return NS_GetSpecialDirectory(NS_ConvertUTF16toUTF8(aSpecialDirectory).get(),
+                                getter_AddRefs(mDisplayDirectory));
+}
+
+// Get the display special directory
+NS_IMETHODIMP nsBaseFilePicker::GetDisplaySpecialDirectory(
+    nsAString& aDirectory) {
+  aDirectory = mDisplaySpecialDirectory;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseFilePicker::GetAddToRecentDocs(bool* aFlag) {
+  *aFlag = mAddToRecentDocs;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseFilePicker::SetAddToRecentDocs(bool aFlag) {
+  mAddToRecentDocs = aFlag;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseFilePicker::GetMode(nsIFilePicker::Mode* aMode) {
+  *aMode = mMode;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseFilePicker::SetOkButtonLabel(const nsAString& aLabel) {
+  mOkButtonLabel = aLabel;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseFilePicker::GetOkButtonLabel(nsAString& aLabel) {
+  aLabel = mOkButtonLabel;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseFilePicker::GetDomFileOrDirectory(nsISupports** aValue) {
+  nsCOMPtr<nsIFile> localFile;
+  nsresult rv = GetFile(getter_AddRefs(localFile));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!localFile) {
+    *aValue = nullptr;
+    return NS_OK;
+  }
+
+  auto* innerParent = mParent ? mParent->GetCurrentInnerWindow() : nullptr;
+
+  if (!innerParent) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return LocalFileToDirectoryOrBlob(
+      innerParent, mMode == nsIFilePicker::modeGetFolder, localFile, aValue);
+}
+
+NS_IMETHODIMP
+nsBaseFilePicker::GetDomFileOrDirectoryEnumerator(
+    nsISimpleEnumerator** aValue) {
+  nsCOMPtr<nsISimpleEnumerator> iter;
+  nsresult rv = GetFiles(getter_AddRefs(iter));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  RefPtr<nsBaseFilePickerEnumerator> retIter =
+      new nsBaseFilePickerEnumerator(mParent, iter, mMode);
+
+  retIter.forget(aValue);
+  return NS_OK;
+}
diff --git a/widget/nsBaseFilePicker.h b/widget/nsBaseFilePicker.h
new file mode 100644
index 0000000000..3d26a1822e
--- /dev/null
+++ b/widget/nsBaseFilePicker.h
@@ -0,0 +1,82 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsBaseFilePicker_h__
+#define nsBaseFilePicker_h__
+
+#include "mozilla/dom/BrowsingContext.h"
+#include "nsISupports.h"
+#include "nsIFilePicker.h"
+#include "nsISimpleEnumerator.h"
+#include "nsArrayEnumerator.h"
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "nsTArray.h"
+
+class nsPIDOMWindowOuter;
+class nsIWidget;
+
+class nsBaseFilePicker : public nsIFilePicker {
+#ifndef XP_WIN
+  class AsyncShowFilePicker;
+#endif
+
+ public:
+  nsBaseFilePicker();
+  virtual ~nsBaseFilePicker();
+
+  NS_IMETHOD Init(mozIDOMWindowProxy* aParent, const nsAString& aTitle,
+                  nsIFilePicker::Mode aMode,
+                  mozilla::dom::BrowsingContext* aBrowsingContext) override;
+  NS_IMETHOD IsModeSupported(nsIFilePicker::Mode aMode, JSContext* aCx,
+                             mozilla::dom::Promise** aPromise) override;
+#ifndef XP_WIN
+  NS_IMETHOD Open(nsIFilePickerShownCallback* aCallback) override;
+#endif
+  NS_IMETHOD Close() override;
+  NS_IMETHOD AppendFilters(int32_t filterMask) override;
+  NS_IMETHOD AppendRawFilter(const nsAString& aFilter) override;
+  NS_IMETHOD GetCapture(nsIFilePicker::CaptureTarget* aCapture) override;
+  NS_IMETHOD SetCapture(nsIFilePicker::CaptureTarget aCapture) override;
+  NS_IMETHOD GetFilterIndex(int32_t* aFilterIndex) override;
+  NS_IMETHOD SetFilterIndex(int32_t aFilterIndex) override;
+  NS_IMETHOD GetFiles(nsISimpleEnumerator** aFiles) override;
+  NS_IMETHOD GetDisplayDirectory(nsIFile** aDisplayDirectory) override;
+  NS_IMETHOD SetDisplayDirectory(nsIFile* aDisplayDirectory) override;
+  NS_IMETHOD GetDisplaySpecialDirectory(nsAString& aDisplayDirectory) override;
+  NS_IMETHOD SetDisplaySpecialDirectory(
+      const nsAString& aDisplayDirectory) override;
+  NS_IMETHOD GetAddToRecentDocs(bool* aFlag) override;
+  NS_IMETHOD SetAddToRecentDocs(bool aFlag) override;
+  NS_IMETHOD GetMode(nsIFilePicker::Mode* aMode) override;
+  NS_IMETHOD SetOkButtonLabel(const nsAString& aLabel) override;
+  NS_IMETHOD GetOkButtonLabel(nsAString& aLabel) override;
+
+  NS_IMETHOD GetDomFileOrDirectory(nsISupports** aValue) override;
+  NS_IMETHOD GetDomFileOrDirectoryEnumerator(
+      nsISimpleEnumerator** aValue) override;
+
+ protected:
+  virtual void InitNative(nsIWidget* aParent, const nsAString& aTitle) = 0;
+  virtual nsresult Show(nsIFilePicker::ResultCode* _retval) = 0;
+
+  virtual nsresult ResolveSpecialDirectory(const nsAString& aSpecialDirectory);
+  bool MaybeBlockFilePicker(nsIFilePickerShownCallback* aCallback);
+
+  bool mAddToRecentDocs;
+  nsCOMPtr<nsIFile> mDisplayDirectory;
+  nsString mDisplaySpecialDirectory;
+
+  nsCOMPtr<nsPIDOMWindowOuter> mParent;
+  // The BrowsingContext from which the file picker is being opened.
+  // Used for content analysis.
+  RefPtr<mozilla::dom::BrowsingContext> mBrowsingContext;
+  nsIFilePicker::Mode mMode;
+  nsString mOkButtonLabel;
+  nsTArray<nsString> mRawFilters;
+};
+
+#endif  // nsBaseFilePicker_h__
diff --git a/widget/nsBaseWidget.cpp b/widget/nsBaseWidget.cpp
new file mode 100644
index 0000000000..35c580c106
--- /dev/null
+++ b/widget/nsBaseWidget.cpp
@@ -0,0 +1,3513 @@
+
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsBaseWidget.h"
+
+#include <utility>
+
+#include "GLConsts.h"
+#include "InputData.h"
+#include "LiveResizeListener.h"
+#include "SwipeTracker.h"
+#include "TouchEvents.h"
+#include "X11UndefineNone.h"
+#include "base/thread.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/GlobalKeyListener.h"
+#include "mozilla/IMEStateManager.h"
+#include "mozilla/Logging.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/NativeKeyBindingsType.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/Sprintf.h"
+#include "mozilla/StaticPrefs_apz.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/StaticPrefs_gfx.h"
+#include "mozilla/StaticPrefs_layers.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEventDispatcherListener.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Unused.h"
+#include "mozilla/VsyncDispatcher.h"
+#include "mozilla/dom/BrowserParent.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/SimpleGestureEventBinding.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/GPUProcessManager.h"
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/layers/APZCCallbackHelper.h"
+#include "mozilla/layers/TouchActionHelper.h"
+#include "mozilla/layers/APZEventState.h"
+#include "mozilla/layers/APZInputBridge.h"
+#include "mozilla/layers/APZThreadUtils.h"
+#include "mozilla/layers/ChromeProcessController.h"
+#include "mozilla/layers/Compositor.h"
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+#include "mozilla/layers/CompositorOptions.h"
+#include "mozilla/layers/IAPZCTreeManager.h"
+#include "mozilla/layers/ImageBridgeChild.h"
+#include "mozilla/layers/InputAPZContext.h"
+#include "mozilla/layers/WebRenderLayerManager.h"
+#include "mozilla/webrender/WebRenderTypes.h"
+#include "mozilla/widget/ScreenManager.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsCOMPtr.h"
+#include "nsContentUtils.h"
+#include "nsDeviceContext.h"
+#include "nsGfxCIID.h"
+#include "nsIAppWindow.h"
+#include "nsIBaseWindow.h"
+#include "nsIContent.h"
+#include "nsIScreenManager.h"
+#include "nsISimpleEnumerator.h"
+#include "nsIWidgetListener.h"
+#include "nsRefPtrHashtable.h"
+#include "nsServiceManagerUtils.h"
+#include "nsWidgetsCID.h"
+#include "nsXULPopupManager.h"
+#include "prdtoa.h"
+#include "prenv.h"
+#ifdef ACCESSIBILITY
+#  include "nsAccessibilityService.h"
+#endif
+#include "gfxConfig.h"
+#include "gfxUtils.h"  // for ToDeviceColor
+#include "mozilla/layers/CompositorSession.h"
+#include "VRManagerChild.h"
+#include "gfxConfig.h"
+#include "nsView.h"
+#include "nsViewManager.h"
+
+static mozilla::LazyLogModule sBaseWidgetLog("BaseWidget");
+
+#ifdef DEBUG
+#  include "nsIObserver.h"
+
+static void debug_RegisterPrefCallbacks();
+
+#endif
+
+#ifdef NOISY_WIDGET_LEAKS
+static int32_t gNumWidgets;
+#endif
+
+using namespace mozilla::dom;
+using namespace mozilla::layers;
+using namespace mozilla::ipc;
+using namespace mozilla::widget;
+using namespace mozilla;
+
+// Async pump timer during injected long touch taps
+#define TOUCH_INJECT_PUMP_TIMER_MSEC 50
+#define TOUCH_INJECT_LONG_TAP_DEFAULT_MSEC 1500
+int32_t nsIWidget::sPointerIdCounter = 0;
+
+// Some statics from nsIWidget.h
+/*static*/
+uint64_t AutoObserverNotifier::sObserverId = 0;
+/*static*/ nsTHashMap<uint64_t, nsCOMPtr<nsIObserver>>
+    AutoObserverNotifier::sSavedObservers;
+
+// The maximum amount of time to let the EnableDragDrop runnable wait in the
+// idle queue before timing out and moving it to the regular queue. Value is in
+// milliseconds.
+const uint32_t kAsyncDragDropTimeout = 1000;
+
+NS_IMPL_ISUPPORTS(nsBaseWidget, nsIWidget, nsISupportsWeakReference)
+
+//-------------------------------------------------------------------------
+//
+// nsBaseWidget constructor
+//
+//-------------------------------------------------------------------------
+
+nsBaseWidget::nsBaseWidget() : nsBaseWidget(BorderStyle::None) {}
+
+nsBaseWidget::nsBaseWidget(BorderStyle aBorderStyle)
+    : mWidgetListener(nullptr),
+      mAttachedWidgetListener(nullptr),
+      mPreviouslyAttachedWidgetListener(nullptr),
+      mCompositorVsyncDispatcher(nullptr),
+      mBorderStyle(aBorderStyle),
+      mBounds(0, 0, 0, 0),
+      mIsTiled(false),
+      mPopupLevel(PopupLevel::Top),
+      mPopupType(PopupType::Any),
+      mHasRemoteContent(false),
+      mUpdateCursor(true),
+      mUseAttachedEvents(false),
+      mIMEHasFocus(false),
+      mIMEHasQuit(false),
+      mIsFullyOccluded(false),
+      mNeedFastSnaphot(false),
+      mCurrentPanGestureBelongsToSwipe(false),
+      mIsPIPWindow(false) {
+#ifdef NOISY_WIDGET_LEAKS
+  gNumWidgets++;
+  printf("WIDGETS+ = %d\n", gNumWidgets);
+#endif
+
+#ifdef DEBUG
+  debug_RegisterPrefCallbacks();
+#endif
+
+  mShutdownObserver = new WidgetShutdownObserver(this);
+}
+
+NS_IMPL_ISUPPORTS(WidgetShutdownObserver, nsIObserver)
+
+WidgetShutdownObserver::WidgetShutdownObserver(nsBaseWidget* aWidget)
+    : mWidget(aWidget), mRegistered(false) {
+  Register();
+}
+
+WidgetShutdownObserver::~WidgetShutdownObserver() {
+  // No need to call Unregister(), we can't be destroyed until nsBaseWidget
+  // gets torn down. The observer service and nsBaseWidget have a ref on us
+  // so nsBaseWidget has to call Unregister and then clear its ref.
+}
+
+NS_IMETHODIMP
+WidgetShutdownObserver::Observe(nsISupports* aSubject, const char* aTopic,
+                                const char16_t* aData) {
+  if (!mWidget) {
+    return NS_OK;
+  }
+  if (!strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
+    RefPtr<nsBaseWidget> widget(mWidget);
+    widget->Shutdown();
+  } else if (!strcmp(aTopic, "quit-application")) {
+    RefPtr<nsBaseWidget> widget(mWidget);
+    widget->QuitIME();
+  }
+  return NS_OK;
+}
+
+void WidgetShutdownObserver::Register() {
+  if (!mRegistered) {
+    mRegistered = true;
+    nsContentUtils::RegisterShutdownObserver(this);
+
+#ifndef MOZ_WIDGET_ANDROID
+    // The primary purpose of observing quit-application is
+    // to avoid leaking a widget on Windows when nothing else
+    // breaks the circular reference between the widget and
+    // TSFTextStore. However, our Android IME code crashes if
+    // doing this on Android, so let's not do this on Android.
+    // Doing this on Gtk and Mac just in case.
+    nsCOMPtr<nsIObserverService> observerService =
+        mozilla::services::GetObserverService();
+    if (observerService) {
+      observerService->AddObserver(this, "quit-application", false);
+    }
+#endif
+  }
+}
+
+void WidgetShutdownObserver::Unregister() {
+  if (mRegistered) {
+    mWidget = nullptr;
+
+#ifndef MOZ_WIDGET_ANDROID
+    nsCOMPtr<nsIObserverService> observerService =
+        mozilla::services::GetObserverService();
+    if (observerService) {
+      observerService->RemoveObserver(this, "quit-application");
+    }
+#endif
+
+    nsContentUtils::UnregisterShutdownObserver(this);
+    mRegistered = false;
+  }
+}
+
+#define INTL_APP_LOCALES_CHANGED "intl:app-locales-changed"
+
+NS_IMPL_ISUPPORTS(LocalesChangedObserver, nsIObserver)
+
+LocalesChangedObserver::LocalesChangedObserver(nsBaseWidget* aWidget)
+    : mWidget(aWidget), mRegistered(false) {
+  Register();
+}
+
+LocalesChangedObserver::~LocalesChangedObserver() {
+  // No need to call Unregister(), we can't be destroyed until nsBaseWidget
+  // gets torn down. The observer service and nsBaseWidget have a ref on us
+  // so nsBaseWidget has to call Unregister and then clear its ref.
+}
+
+NS_IMETHODIMP
+LocalesChangedObserver::Observe(nsISupports* aSubject, const char* aTopic,
+                                const char16_t* aData) {
+  if (!mWidget) {
+    return NS_OK;
+  }
+  if (!strcmp(aTopic, INTL_APP_LOCALES_CHANGED)) {
+    RefPtr<nsBaseWidget> widget(mWidget);
+    widget->LocalesChanged();
+  }
+  return NS_OK;
+}
+
+void LocalesChangedObserver::Register() {
+  if (mRegistered) {
+    return;
+  }
+
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    obs->AddObserver(this, INTL_APP_LOCALES_CHANGED, true);
+  }
+
+  // Locale might be update before registering
+  RefPtr<nsBaseWidget> widget(mWidget);
+  widget->LocalesChanged();
+
+  mRegistered = true;
+}
+
+void LocalesChangedObserver::Unregister() {
+  if (!mRegistered) {
+    return;
+  }
+
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    obs->RemoveObserver(this, INTL_APP_LOCALES_CHANGED);
+  }
+
+  mWidget = nullptr;
+  mRegistered = false;
+}
+
+void nsBaseWidget::Shutdown() {
+  NotifyLiveResizeStopped();
+  DestroyCompositor();
+  FreeLocalesChangedObserver();
+  FreeShutdownObserver();
+}
+
+void nsBaseWidget::QuitIME() {
+  IMEStateManager::WidgetOnQuit(this);
+  this->mIMEHasQuit = true;
+}
+
+void nsBaseWidget::DestroyCompositor() {
+  RevokeTransactionIdAllocator();
+
+  // We release this before releasing the compositor, since it may hold the
+  // last reference to our ClientLayerManager. ClientLayerManager's dtor can
+  // trigger a paint, creating a new compositor, and we don't want to re-use
+  // the old vsync dispatcher.
+  if (mCompositorVsyncDispatcher) {
+    MOZ_ASSERT(mCompositorVsyncDispatcherLock.get());
+
+    MutexAutoLock lock(*mCompositorVsyncDispatcherLock.get());
+    mCompositorVsyncDispatcher->Shutdown();
+    mCompositorVsyncDispatcher = nullptr;
+  }
+
+  // The compositor shutdown sequence looks like this:
+  //  1. CompositorSession calls CompositorBridgeChild::Destroy.
+  //  2. CompositorBridgeChild synchronously sends WillClose.
+  //  3. CompositorBridgeParent releases some resources (such as the layer
+  //     manager, compositor, and widget).
+  //  4. CompositorBridgeChild::Destroy returns.
+  //  5. Asynchronously, CompositorBridgeParent::ActorDestroy will fire on the
+  //     compositor thread when the I/O thread closes the IPC channel.
+  //  6. Step 5 will schedule DeferredDestroy on the compositor thread, which
+  //     releases the reference CompositorBridgeParent holds to itself.
+  //
+  // When CompositorSession::Shutdown returns, we assume the compositor is gone
+  // or will be gone very soon.
+  if (mCompositorSession) {
+    ReleaseContentController();
+    mAPZC = nullptr;
+    SetCompositorWidgetDelegate(nullptr);
+    mCompositorBridgeChild = nullptr;
+    mCompositorSession->Shutdown();
+    mCompositorSession = nullptr;
+  }
+}
+
+// This prevents the layer manager from starting a new transaction during
+// shutdown.
+void nsBaseWidget::RevokeTransactionIdAllocator() {
+  if (!mWindowRenderer || !mWindowRenderer->AsWebRender()) {
+    return;
+  }
+  mWindowRenderer->AsWebRender()->SetTransactionIdAllocator(nullptr);
+}
+
+void nsBaseWidget::ReleaseContentController() {
+  if (mRootContentController) {
+    mRootContentController->Destroy();
+    mRootContentController = nullptr;
+  }
+}
+
+void nsBaseWidget::DestroyLayerManager() {
+  if (mWindowRenderer) {
+    mWindowRenderer->Destroy();
+    mWindowRenderer = nullptr;
+  }
+  DestroyCompositor();
+}
+
+void nsBaseWidget::OnRenderingDeviceReset() { DestroyLayerManager(); }
+
+void nsBaseWidget::FreeShutdownObserver() {
+  if (mShutdownObserver) {
+    mShutdownObserver->Unregister();
+  }
+  mShutdownObserver = nullptr;
+}
+
+void nsBaseWidget::FreeLocalesChangedObserver() {
+  if (mLocalesChangedObserver) {
+    mLocalesChangedObserver->Unregister();
+  }
+  mLocalesChangedObserver = nullptr;
+}
+
+//-------------------------------------------------------------------------
+//
+// nsBaseWidget destructor
+//
+//-------------------------------------------------------------------------
+
+nsBaseWidget::~nsBaseWidget() {
+  if (mSwipeTracker) {
+    mSwipeTracker->Destroy();
+    mSwipeTracker = nullptr;
+  }
+
+  IMEStateManager::WidgetDestroyed(this);
+
+  FreeLocalesChangedObserver();
+  FreeShutdownObserver();
+  DestroyLayerManager();
+
+#ifdef NOISY_WIDGET_LEAKS
+  gNumWidgets--;
+  printf("WIDGETS- = %d\n", gNumWidgets);
+#endif
+}
+
+//-------------------------------------------------------------------------
+//
+// Basic create.
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::BaseCreate(nsIWidget* aParent, widget::InitData* aInitData) {
+  if (aInitData) {
+    mWindowType = aInitData->mWindowType;
+    mBorderStyle = aInitData->mBorderStyle;
+    mPopupLevel = aInitData->mPopupLevel;
+    mPopupType = aInitData->mPopupHint;
+    mHasRemoteContent = aInitData->mHasRemoteContent;
+    mIsPIPWindow = aInitData->mPIPWindow;
+  }
+
+  if (aParent) {
+    aParent->AddChild(this);
+  }
+}
+
+//-------------------------------------------------------------------------
+//
+// Accessor functions to get/set the client data
+//
+//-------------------------------------------------------------------------
+
+nsIWidgetListener* nsBaseWidget::GetWidgetListener() const {
+  return mWidgetListener;
+}
+
+void nsBaseWidget::SetWidgetListener(nsIWidgetListener* aWidgetListener) {
+  mWidgetListener = aWidgetListener;
+}
+
+already_AddRefed<nsIWidget> nsBaseWidget::CreateChild(
+    const LayoutDeviceIntRect& aRect, widget::InitData* aInitData,
+    bool aForceUseIWidgetParent) {
+  nsIWidget* parent = this;
+  nsNativeWidget nativeParent = nullptr;
+
+  if (!aForceUseIWidgetParent) {
+    // Use only either parent or nativeParent, not both, to match
+    // existing code.  Eventually Create() should be divested of its
+    // nativeWidget parameter.
+    nativeParent = parent ? parent->GetNativeData(NS_NATIVE_WIDGET) : nullptr;
+    parent = nativeParent ? nullptr : parent;
+    MOZ_ASSERT(!parent || !nativeParent, "messed up logic");
+  }
+
+  nsCOMPtr<nsIWidget> widget;
+  if (aInitData && aInitData->mWindowType == WindowType::Popup) {
+    widget = AllocateChildPopupWidget();
+  } else {
+    widget = nsIWidget::CreateChildWindow();
+  }
+
+  if (widget && mNeedFastSnaphot) {
+    widget->SetNeedFastSnaphot();
+  }
+
+  if (widget &&
+      NS_SUCCEEDED(widget->Create(parent, nativeParent, aRect, aInitData))) {
+    return widget.forget();
+  }
+
+  return nullptr;
+}
+
+// Attach a view to our widget which we'll send events to.
+void nsBaseWidget::AttachViewToTopLevel(bool aUseAttachedEvents) {
+  NS_ASSERTION((mWindowType == WindowType::TopLevel ||
+                mWindowType == WindowType::Dialog ||
+                mWindowType == WindowType::Invisible ||
+                mWindowType == WindowType::Child),
+               "Can't attach to window of that type");
+
+  mUseAttachedEvents = aUseAttachedEvents;
+}
+
+nsIWidgetListener* nsBaseWidget::GetAttachedWidgetListener() const {
+  return mAttachedWidgetListener;
+}
+
+nsIWidgetListener* nsBaseWidget::GetPreviouslyAttachedWidgetListener() {
+  return mPreviouslyAttachedWidgetListener;
+}
+
+void nsBaseWidget::SetPreviouslyAttachedWidgetListener(
+    nsIWidgetListener* aListener) {
+  mPreviouslyAttachedWidgetListener = aListener;
+}
+
+void nsBaseWidget::SetAttachedWidgetListener(nsIWidgetListener* aListener) {
+  mAttachedWidgetListener = aListener;
+}
+
+//-------------------------------------------------------------------------
+//
+// Close this nsBaseWidget
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::Destroy() {
+  DestroyCompositor();
+
+  // Just in case our parent is the only ref to us
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
+  // disconnect from the parent
+  nsIWidget* parent = GetParent();
+  if (parent) {
+    parent->RemoveChild(this);
+  }
+}
+
+//-------------------------------------------------------------------------
+//
+// Get this nsBaseWidget parent
+//
+//-------------------------------------------------------------------------
+nsIWidget* nsBaseWidget::GetParent(void) { return nullptr; }
+
+//-------------------------------------------------------------------------
+//
+// Get this nsBaseWidget top level widget
+//
+//-------------------------------------------------------------------------
+nsIWidget* nsBaseWidget::GetTopLevelWidget() {
+  nsIWidget *topLevelWidget = nullptr, *widget = this;
+  while (widget) {
+    topLevelWidget = widget;
+    widget = widget->GetParent();
+  }
+  return topLevelWidget;
+}
+
+//-------------------------------------------------------------------------
+//
+// Get this nsBaseWidget's top (non-sheet) parent (if it's a sheet)
+//
+//-------------------------------------------------------------------------
+nsIWidget* nsBaseWidget::GetSheetWindowParent(void) { return nullptr; }
+
+float nsBaseWidget::GetDPI() { return 96.0f; }
+
+CSSToLayoutDeviceScale nsIWidget::GetDefaultScale() {
+  double devPixelsPerCSSPixel = StaticPrefs::layout_css_devPixelsPerPx();
+
+  if (devPixelsPerCSSPixel <= 0.0) {
+    devPixelsPerCSSPixel = GetDefaultScaleInternal();
+  }
+
+  return CSSToLayoutDeviceScale(devPixelsPerCSSPixel);
+}
+
+nsIntSize nsIWidget::CustomCursorSize(const Cursor& aCursor) {
+  MOZ_ASSERT(aCursor.IsCustom());
+  int32_t width = 0;
+  int32_t height = 0;
+  aCursor.mContainer->GetWidth(&width);
+  aCursor.mContainer->GetHeight(&height);
+  aCursor.mResolution.ApplyTo(width, height);
+  return {width, height};
+}
+
+LayoutDeviceIntSize nsIWidget::ClientToWindowSizeDifference() {
+  auto margin = ClientToWindowMargin();
+  MOZ_ASSERT(margin.top >= 0, "Window should be bigger than client area");
+  MOZ_ASSERT(margin.left >= 0, "Window should be bigger than client area");
+  MOZ_ASSERT(margin.right >= 0, "Window should be bigger than client area");
+  MOZ_ASSERT(margin.bottom >= 0, "Window should be bigger than client area");
+  return {margin.LeftRight(), margin.TopBottom()};
+}
+
+RefPtr<mozilla::VsyncDispatcher> nsIWidget::GetVsyncDispatcher() {
+  return nullptr;
+}
+
+//-------------------------------------------------------------------------
+//
+// Add a child to the list of children
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::AddChild(nsIWidget* aChild) {
+  MOZ_ASSERT(!aChild->GetNextSibling() && !aChild->GetPrevSibling(),
+             "aChild not properly removed from its old child list");
+
+  if (!mFirstChild) {
+    mFirstChild = mLastChild = aChild;
+  } else {
+    // append to the list
+    MOZ_ASSERT(mLastChild);
+    MOZ_ASSERT(!mLastChild->GetNextSibling());
+    mLastChild->SetNextSibling(aChild);
+    aChild->SetPrevSibling(mLastChild);
+    mLastChild = aChild;
+  }
+}
+
+//-------------------------------------------------------------------------
+//
+// Remove a child from the list of children
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::RemoveChild(nsIWidget* aChild) {
+#ifdef DEBUG
+#  ifdef XP_MACOSX
+  // nsCocoaWindow doesn't implement GetParent, so in that case parent will be
+  // null and we'll just have to do without this assertion.
+  nsIWidget* parent = aChild->GetParent();
+  NS_ASSERTION(!parent || parent == this, "Not one of our kids!");
+#  else
+  MOZ_RELEASE_ASSERT(aChild->GetParent() == this, "Not one of our kids!");
+#  endif
+#endif
+
+  if (mLastChild == aChild) {
+    mLastChild = mLastChild->GetPrevSibling();
+  }
+  if (mFirstChild == aChild) {
+    mFirstChild = mFirstChild->GetNextSibling();
+  }
+
+  // Now remove from the list.  Make sure that we pass ownership of the tail
+  // of the list correctly before we have aChild let go of it.
+  nsIWidget* prev = aChild->GetPrevSibling();
+  nsIWidget* next = aChild->GetNextSibling();
+  if (prev) {
+    prev->SetNextSibling(next);
+  }
+  if (next) {
+    next->SetPrevSibling(prev);
+  }
+
+  aChild->SetNextSibling(nullptr);
+  aChild->SetPrevSibling(nullptr);
+}
+
+//-------------------------------------------------------------------------
+//
+// Sets widget's position within its parent's child list.
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::SetZIndex(int32_t aZIndex) {
+  // Hold a ref to ourselves just in case, since we're going to remove
+  // from our parent.
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
+
+  mZIndex = aZIndex;
+
+  // reorder this child in its parent's list.
+  auto* parent = static_cast<nsBaseWidget*>(GetParent());
+  if (parent) {
+    parent->RemoveChild(this);
+    // Scope sib outside the for loop so we can check it afterward
+    nsIWidget* sib = parent->GetFirstChild();
+    for (; sib; sib = sib->GetNextSibling()) {
+      int32_t childZIndex = GetZIndex();
+      if (aZIndex < childZIndex) {
+        // Insert ourselves before sib
+        nsIWidget* prev = sib->GetPrevSibling();
+        mNextSibling = sib;
+        mPrevSibling = prev;
+        sib->SetPrevSibling(this);
+        if (prev) {
+          prev->SetNextSibling(this);
+        } else {
+          NS_ASSERTION(sib == parent->mFirstChild, "Broken child list");
+          // We've taken ownership of sib, so it's safe to have parent let
+          // go of it
+          parent->mFirstChild = this;
+        }
+        PlaceBehind(eZPlacementBelow, sib, false);
+        break;
+      }
+    }
+    // were we added to the list?
+    if (!sib) {
+      parent->AddChild(this);
+    }
+  }
+}
+
+void nsBaseWidget::GetWorkspaceID(nsAString& workspaceID) {
+  workspaceID.Truncate();
+}
+
+void nsBaseWidget::MoveToWorkspace(const nsAString& workspaceID) {
+  // Noop.
+}
+
+//-------------------------------------------------------------------------
+//
+// Get this component cursor
+//
+//-------------------------------------------------------------------------
+
+void nsBaseWidget::SetCursor(const Cursor& aCursor) { mCursor = aCursor; }
+
+void nsBaseWidget::SetCustomCursorAllowed(bool aIsAllowed) {
+  if (aIsAllowed != mCustomCursorAllowed) {
+    mCustomCursorAllowed = aIsAllowed;
+    mUpdateCursor = true;
+    SetCursor(mCursor);
+  }
+}
+
+//-------------------------------------------------------------------------
+//
+// Window transparency methods
+//
+//-------------------------------------------------------------------------
+
+void nsBaseWidget::SetTransparencyMode(TransparencyMode aMode) {}
+
+TransparencyMode nsBaseWidget::GetTransparencyMode() {
+  return TransparencyMode::Opaque;
+}
+
+/* virtual */
+void nsBaseWidget::PerformFullscreenTransition(FullscreenTransitionStage aStage,
+                                               uint16_t aDuration,
+                                               nsISupports* aData,
+                                               nsIRunnable* aCallback) {
+  MOZ_ASSERT_UNREACHABLE(
+      "Should never call PerformFullscreenTransition on nsBaseWidget");
+}
+
+//-------------------------------------------------------------------------
+//
+// Put the window into full-screen mode
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::InfallibleMakeFullScreen(bool aFullScreen) {
+#define MOZ_FORMAT_RECT(fmtstr) "[" fmtstr "," fmtstr " " fmtstr "x" fmtstr "]"
+#define MOZ_SPLAT_RECT(rect) \
+  (rect).X(), (rect).Y(), (rect).Width(), (rect).Height()
+
+  // Windows which can be made fullscreen are exactly those which are located on
+  // the desktop, rather than being a child of some other window.
+  MOZ_DIAGNOSTIC_ASSERT(BoundsUseDesktopPixels(),
+                        "non-desktop windows cannot be made fullscreen");
+
+  // Ensure that the OS chrome is hidden/shown before we resize and/or exit the
+  // function.
+  //
+  // HideWindowChrome() may (depending on platform, implementation details, and
+  // OS-level user preferences) alter the reported size of the window. The
+  // obvious and principled solution is socks-and-shoes:
+  //   - On entering fullscreen mode: hide window chrome, then perform resize.
+  //   - On leaving fullscreen mode: unperform resize, then show window chrome.
+  //
+  // ... unfortunately, HideWindowChrome() requires Resize() to be called
+  // afterwards (see bug 498835), which prevents this from being done in a
+  // straightforward way.
+  //
+  // Instead, we always call HideWindowChrome() just before we call Resize().
+  // This at least ensures that our measurements are consistently taken in a
+  // pre-transition state.
+  //
+  // ... unfortunately again, coupling HideWindowChrome() to Resize() means that
+  // we have to worry about the possibility of control flows that don't call
+  // Resize() at all. (That shouldn't happen, but it's not trivial to rule out.)
+  // We therefore set up a fallback to fix up the OS chrome if it hasn't been
+  // done at exit time.
+  bool hasAdjustedOSChrome = false;
+  const auto adjustOSChrome = [&]() {
+    if (hasAdjustedOSChrome) {
+      MOZ_ASSERT_UNREACHABLE("window chrome should only be adjusted once");
+      return;
+    }
+    HideWindowChrome(aFullScreen);
+    hasAdjustedOSChrome = true;
+  };
+  const auto adjustChromeOnScopeExit = MakeScopeExit([&]() {
+    if (hasAdjustedOSChrome) {
+      return;
+    }
+
+    MOZ_LOG(sBaseWidgetLog, LogLevel::Warning,
+            ("window was not resized within InfallibleMakeFullScreen()"));
+
+    // Hide chrome and "resize" the window to its current size.
+    auto rect = GetBounds();
+    adjustOSChrome();
+    Resize(rect.X(), rect.Y(), rect.Width(), rect.Height(), true);
+  });
+
+  // Attempt to resize to `rect`.
+  //
+  // Returns the actual rectangle resized to. (This may differ from `rect`, if
+  // the OS is unhappy with it. See bug 1786226.)
+  const auto doReposition = [&](auto rect) -> void {
+    static_assert(std::is_base_of_v<DesktopPixel,
+                                    std::remove_reference_t<decltype(rect)>>,
+                  "doReposition requires a rectangle using desktop pixels");
+
+    if (MOZ_LOG_TEST(sBaseWidgetLog, LogLevel::Debug)) {
+      const DesktopRect previousSize =
+          GetScreenBounds() / GetDesktopToDeviceScale();
+      MOZ_LOG(sBaseWidgetLog, LogLevel::Debug,
+              ("before resize: " MOZ_FORMAT_RECT("%f"),
+               MOZ_SPLAT_RECT(previousSize)));
+    }
+
+    adjustOSChrome();
+    Resize(rect.X(), rect.Y(), rect.Width(), rect.Height(), true);
+
+    if (MOZ_LOG_TEST(sBaseWidgetLog, LogLevel::Warning)) {
+      // `rect` may have any underlying data type; coerce to float to
+      // simplify printf-style logging
+      const gfx::RectTyped<DesktopPixel, float> rectAsFloat{rect};
+
+      // The OS may have objected to the target position. That's not necessarily
+      // a problem -- it'll happen regularly on Macs with camera notches in the
+      // monitor, for instance (see bug 1786226) -- but it probably deserves to
+      // be called out.
+      //
+      // Since there's floating-point math involved, the actual values may be
+      // off by a few ulps -- as an upper bound, perhaps 8 * FLT_EPSILON *
+      // max(MOZ_SPLAT_RECT(rect)) -- but 0.01 should be several orders of
+      // magnitude bigger than that.
+
+      const auto postResizeRectRaw = GetScreenBounds();
+      const auto postResizeRect = postResizeRectRaw / GetDesktopToDeviceScale();
+      const bool succeeded = postResizeRect.WithinEpsilonOf(rectAsFloat, 0.01);
+
+      if (succeeded) {
+        MOZ_LOG(sBaseWidgetLog, LogLevel::Debug,
+                ("resized to: " MOZ_FORMAT_RECT("%f"),
+                 MOZ_SPLAT_RECT(rectAsFloat)));
+      } else {
+        MOZ_LOG(sBaseWidgetLog, LogLevel::Warning,
+                ("attempted to resize to: " MOZ_FORMAT_RECT("%f"),
+                 MOZ_SPLAT_RECT(rectAsFloat)));
+        MOZ_LOG(sBaseWidgetLog, LogLevel::Warning,
+                ("... but ended up at: " MOZ_FORMAT_RECT("%f"),
+                 MOZ_SPLAT_RECT(postResizeRect)));
+      }
+
+      MOZ_LOG(
+          sBaseWidgetLog, LogLevel::Verbose,
+          ("(... which, before DPI adjustment, is:" MOZ_FORMAT_RECT("%d") ")",
+           MOZ_SPLAT_RECT(postResizeRectRaw)));
+    }
+  };
+
+  if (aFullScreen) {
+    if (!mSavedBounds) {
+      mSavedBounds = Some(FullscreenSavedState());
+    }
+    // save current position
+    mSavedBounds->windowRect = GetScreenBounds() / GetDesktopToDeviceScale();
+
+    nsCOMPtr<nsIScreen> screen = GetWidgetScreen();
+    if (!screen) {
+      return;
+    }
+
+    // Move to fill the screen.
+    doReposition(screen->GetRectDisplayPix());
+    // Save off the new position. (This may differ from GetRectDisplayPix(), if
+    // the OS was unhappy with it. See bug 1786226.)
+    mSavedBounds->screenRect = GetScreenBounds() / GetDesktopToDeviceScale();
+  } else {
+    if (!mSavedBounds) {
+      // This should never happen, at present, since we don't make windows
+      // fullscreen at their creation time; but it's not logically impossible.
+      MOZ_ASSERT(false, "fullscreen window did not have saved position");
+      return;
+    }
+
+    // Figure out where to go from here.
+    //
+    // Fortunately, since we're currently fullscreen (and other code should be
+    // handling _keeping_ us fullscreen even after display-layout changes),
+    // there's an obvious choice for which display we should attach to; all we
+    // need to determine is where on that display we should go.
+
+    const DesktopRect currentWinRect =
+        GetScreenBounds() / GetDesktopToDeviceScale();
+
+    // Optimization: if where we are is where we were, then where we originally
+    // came from is where we're going to go.
+    if (currentWinRect == DesktopRect(mSavedBounds->screenRect)) {
+      MOZ_LOG(sBaseWidgetLog, LogLevel::Debug,
+              ("no location change detected; returning to saved location"));
+      doReposition(mSavedBounds->windowRect);
+      return;
+    }
+
+    /*
+      General case: figure out where we're going to go by dividing where we are
+      by where we were, and then multiplying by where we originally came from.
+
+      Less abstrusely: resize so that we occupy the same proportional position
+      on our current display after leaving fullscreen as we occupied on our
+      previous display before entering fullscreen.
+
+      (N.B.: We do not clamp. If we were only partially on the old display,
+      we'll be only partially on the new one, too.)
+    */
+
+    MOZ_LOG(sBaseWidgetLog, LogLevel::Debug,
+            ("location change detected; computing new destination"));
+
+    // splat: convert an arbitrary Rect into a tuple, for syntactic convenience.
+    const auto splat = [](auto rect) {
+      return std::tuple(rect.X(), rect.Y(), rect.Width(), rect.Height());
+    };
+
+    // remap: find the unique affine mapping which transforms `src` to `dst`,
+    // and apply it to `val`.
+    using Range = std::pair<float, float>;
+    const auto remap = [](Range dst, Range src, float val) {
+      // linear interpolation and its inverse: lerp(a, b, invlerp(a, b, t)) == t
+      const auto lerp = [](float lo, float hi, float t) {
+        return lo + t * (hi - lo);
+      };
+      const auto invlerp = [](float lo, float hi, float mid) {
+        return (mid - lo) / (hi - lo);
+      };
+
+      const auto [dst_a, dst_b] = dst;
+      const auto [src_a, src_b] = src;
+      return lerp(dst_a, dst_b, invlerp(src_a, src_b, val));
+    };
+
+    // original position
+    const auto [px, py, pw, ph] = splat(mSavedBounds->windowRect);
+    // source desktop rect
+    const auto [sx, sy, sw, sh] = splat(mSavedBounds->screenRect);
+    // target desktop rect
+    const auto [tx, ty, tw, th] = splat(currentWinRect);
+
+    const float nx = remap({tx, tx + tw}, {sx, sx + sw}, px);
+    const float ny = remap({ty, ty + th}, {sy, sy + sh}, py);
+    const float nw = remap({0, tw}, {0, sw}, pw);
+    const float nh = remap({0, th}, {0, sh}, ph);
+
+    doReposition(DesktopRect{nx, ny, nw, nh});
+  }
+
+#undef MOZ_SPLAT_RECT
+#undef MOZ_FORMAT_RECT
+}
+
+nsresult nsBaseWidget::MakeFullScreen(bool aFullScreen) {
+  InfallibleMakeFullScreen(aFullScreen);
+  return NS_OK;
+}
+
+nsBaseWidget::AutoLayerManagerSetup::AutoLayerManagerSetup(
+    nsBaseWidget* aWidget, gfxContext* aTarget, BufferMode aDoubleBuffering)
+    : mWidget(aWidget) {
+  WindowRenderer* renderer = mWidget->GetWindowRenderer();
+  if (renderer->AsFallback()) {
+    mRenderer = renderer->AsFallback();
+    mRenderer->SetTarget(aTarget, aDoubleBuffering);
+  }
+}
+
+nsBaseWidget::AutoLayerManagerSetup::~AutoLayerManagerSetup() {
+  if (mRenderer) {
+    mRenderer->SetTarget(nullptr, mozilla::layers::BufferMode::BUFFER_NONE);
+  }
+}
+
+bool nsBaseWidget::IsSmallPopup() const {
+  return mWindowType == WindowType::Popup && mPopupType != PopupType::Panel;
+}
+
+bool nsBaseWidget::ComputeShouldAccelerate() {
+  return gfx::gfxConfig::IsEnabled(gfx::Feature::HW_COMPOSITING) &&
+         (WidgetTypeSupportsAcceleration() ||
+          StaticPrefs::gfx_webrender_unaccelerated_widget_force());
+}
+
+bool nsBaseWidget::UseAPZ() {
+  return (gfxPlatform::AsyncPanZoomEnabled() &&
+          (mWindowType == WindowType::TopLevel ||
+           mWindowType == WindowType::Child ||
+           ((mWindowType == WindowType::Popup ||
+             mWindowType == WindowType::Dialog) &&
+            HasRemoteContent() && StaticPrefs::apz_popups_enabled())));
+}
+
+void nsBaseWidget::CreateCompositor() {
+  LayoutDeviceIntRect rect = GetBounds();
+  CreateCompositor(rect.Width(), rect.Height());
+}
+
+void nsIWidget::PauseOrResumeCompositor(bool aPause) {
+  auto* renderer = GetRemoteRenderer();
+  if (!renderer) {
+    return;
+  }
+  if (aPause) {
+    renderer->SendPause();
+  } else {
+    renderer->SendResume();
+  }
+}
+
+already_AddRefed<GeckoContentController>
+nsBaseWidget::CreateRootContentController() {
+  RefPtr<GeckoContentController> controller =
+      new ChromeProcessController(this, mAPZEventState, mAPZC);
+  return controller.forget();
+}
+
+void nsBaseWidget::ConfigureAPZCTreeManager() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mAPZC);
+
+  mAPZC->SetDPI(GetDPI());
+
+  if (StaticPrefs::apz_keyboard_enabled_AtStartup()) {
+    KeyboardMap map = RootWindowGlobalKeyListener::CollectKeyboardShortcuts();
+    mAPZC->SetKeyboardMap(map);
+  }
+
+  ContentReceivedInputBlockCallback callback(
+      [treeManager = RefPtr{mAPZC.get()}](uint64_t aInputBlockId,
+                                          bool aPreventDefault) {
+        MOZ_ASSERT(NS_IsMainThread());
+        treeManager->ContentReceivedInputBlock(aInputBlockId, aPreventDefault);
+      });
+  mAPZEventState = new APZEventState(this, std::move(callback));
+
+  mRootContentController = CreateRootContentController();
+  if (mRootContentController) {
+    mCompositorSession->SetContentController(mRootContentController);
+  }
+
+  // When APZ is enabled, we can actually enable raw touch events because we
+  // have code that can deal with them properly. If APZ is not enabled, this
+  // function doesn't get called.
+  if (StaticPrefs::dom_w3c_touch_events_enabled()) {
+    RegisterTouchWindow();
+  }
+}
+
+void nsBaseWidget::ConfigureAPZControllerThread() {
+  // By default the controller thread is the main thread.
+  APZThreadUtils::SetControllerThread(NS_GetCurrentThread());
+}
+
+void nsBaseWidget::SetConfirmedTargetAPZC(
+    uint64_t aInputBlockId,
+    const nsTArray<ScrollableLayerGuid>& aTargets) const {
+  mAPZC->SetTargetAPZC(aInputBlockId, aTargets);
+}
+
+void nsBaseWidget::UpdateZoomConstraints(
+    const uint32_t& aPresShellId, const ScrollableLayerGuid::ViewID& aViewId,
+    const Maybe<ZoomConstraints>& aConstraints) {
+  if (!mCompositorSession || !mAPZC) {
+    MOZ_ASSERT_IF(mInitialZoomConstraints,
+                  mInitialZoomConstraints->mViewID == aViewId);
+    if (aConstraints) {
+      // We have some constraints, but the compositor and APZC aren't
+      // created yet. Save these so we can use them later.
+      mInitialZoomConstraints = Some(
+          InitialZoomConstraints(aPresShellId, aViewId, aConstraints.ref()));
+    } else {
+      mInitialZoomConstraints.reset();
+    }
+    return;
+  }
+  LayersId layersId = mCompositorSession->RootLayerTreeId();
+  mAPZC->UpdateZoomConstraints(
+      ScrollableLayerGuid(layersId, aPresShellId, aViewId), aConstraints);
+}
+
+bool nsBaseWidget::AsyncPanZoomEnabled() const { return !!mAPZC; }
+
+nsEventStatus nsBaseWidget::ProcessUntransformedAPZEvent(
+    WidgetInputEvent* aEvent, const APZEventResult& aApzResult) {
+  MOZ_ASSERT(NS_IsMainThread());
+  ScrollableLayerGuid targetGuid = aApzResult.mTargetGuid;
+  uint64_t inputBlockId = aApzResult.mInputBlockId;
+  InputAPZContext context(aApzResult.mTargetGuid, inputBlockId,
+                          aApzResult.GetStatus());
+
+  // Make a copy of the original event for the APZCCallbackHelper helpers that
+  // we call later, because the event passed to DispatchEvent can get mutated in
+  // ways that we don't want (i.e. touch points can get stripped out).
+  nsEventStatus status;
+  UniquePtr<WidgetEvent> original(aEvent->Duplicate());
+  DispatchEvent(aEvent, status);
+
+  if (mAPZC && !InputAPZContext::WasRoutedToChildProcess() &&
+      !InputAPZContext::WasDropped() && inputBlockId) {
+    // EventStateManager did not route the event into the child process and
+    // the event was dispatched in the parent process.
+    // It's safe to communicate to APZ that the event has been processed.
+    // Note that here aGuid.mLayersId might be different from
+    // mCompositorSession->RootLayerTreeId() because the event might have gotten
+    // hit-tested by APZ to be targeted at a child process, but a parent process
+    // event listener called preventDefault on it. In that case aGuid.mLayersId
+    // would still be the layers id for the child process, but the event would
+    // not have actually gotten routed to the child process. The main-thread
+    // hit-test result therefore needs to use the parent process layers id.
+    LayersId rootLayersId = mCompositorSession->RootLayerTreeId();
+
+    RefPtr<DisplayportSetListener> postLayerization;
+    if (WidgetTouchEvent* touchEvent = aEvent->AsTouchEvent()) {
+      nsTArray<TouchBehaviorFlags> allowedTouchBehaviors;
+      if (touchEvent->mMessage == eTouchStart) {
+        auto& originalEvent = *original->AsTouchEvent();
+        MOZ_ASSERT(NS_IsMainThread());
+        allowedTouchBehaviors = TouchActionHelper::GetAllowedTouchBehavior(
+            this, GetDocument(), originalEvent);
+        if (!allowedTouchBehaviors.IsEmpty()) {
+          mAPZC->SetAllowedTouchBehavior(inputBlockId, allowedTouchBehaviors);
+        }
+        postLayerization = APZCCallbackHelper::SendSetTargetAPZCNotification(
+            this, GetDocument(), originalEvent, rootLayersId, inputBlockId);
+      }
+      mAPZEventState->ProcessTouchEvent(*touchEvent, targetGuid, inputBlockId,
+                                        aApzResult.GetStatus(), status,
+                                        std::move(allowedTouchBehaviors));
+    } else if (WidgetWheelEvent* wheelEvent = aEvent->AsWheelEvent()) {
+      MOZ_ASSERT(wheelEvent->mFlags.mHandledByAPZ);
+      postLayerization = APZCCallbackHelper::SendSetTargetAPZCNotification(
+          this, GetDocument(), *original->AsWheelEvent(), rootLayersId,
+          inputBlockId);
+      if (wheelEvent->mCanTriggerSwipe) {
+        ReportSwipeStarted(inputBlockId, wheelEvent->TriggersSwipe());
+      }
+      mAPZEventState->ProcessWheelEvent(*wheelEvent, inputBlockId);
+    } else if (WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent()) {
+      MOZ_ASSERT(mouseEvent->mFlags.mHandledByAPZ);
+      postLayerization = APZCCallbackHelper::SendSetTargetAPZCNotification(
+          this, GetDocument(), *original->AsMouseEvent(), rootLayersId,
+          inputBlockId);
+      mAPZEventState->ProcessMouseEvent(*mouseEvent, inputBlockId);
+    }
+    if (postLayerization) {
+      postLayerization->Register();
+    }
+  }
+
+  return status;
+}
+
+template <class InputType, class EventType>
+class DispatchEventOnMainThread : public Runnable {
+ public:
+  DispatchEventOnMainThread(const InputType& aInput, nsBaseWidget* aWidget,
+                            const APZEventResult& aAPZResult)
+      : mozilla::Runnable("DispatchEventOnMainThread"),
+        mInput(aInput),
+        mWidget(aWidget),
+        mAPZResult(aAPZResult) {}
+
+  NS_IMETHOD Run() override {
+    EventType event = mInput.ToWidgetEvent(mWidget);
+    mWidget->ProcessUntransformedAPZEvent(&event, mAPZResult);
+    return NS_OK;
+  }
+
+ private:
+  InputType mInput;
+  nsBaseWidget* mWidget;
+  APZEventResult mAPZResult;
+};
+
+template <class InputType, class EventType>
+class DispatchInputOnControllerThread : public Runnable {
+ public:
+  enum class APZOnly { Yes, No };
+  DispatchInputOnControllerThread(const EventType& aEvent,
+                                  IAPZCTreeManager* aAPZC,
+                                  nsBaseWidget* aWidget,
+                                  APZOnly aAPZOnly = APZOnly::No)
+      : mozilla::Runnable("DispatchInputOnControllerThread"),
+        mMainMessageLoop(MessageLoop::current()),
+        mInput(aEvent),
+        mAPZC(aAPZC),
+        mWidget(aWidget),
+        mAPZOnly(aAPZOnly) {}
+
+  NS_IMETHOD Run() override {
+    APZEventResult result = mAPZC->InputBridge()->ReceiveInputEvent(mInput);
+    if (mAPZOnly == APZOnly::Yes ||
+        result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+      return NS_OK;
+    }
+    RefPtr<Runnable> r = new DispatchEventOnMainThread<InputType, EventType>(
+        mInput, mWidget, result);
+    mMainMessageLoop->PostTask(r.forget());
+    return NS_OK;
+  }
+
+ private:
+  MessageLoop* mMainMessageLoop;
+  InputType mInput;
+  RefPtr<IAPZCTreeManager> mAPZC;
+  nsBaseWidget* mWidget;
+  const APZOnly mAPZOnly;
+};
+
+void nsBaseWidget::DispatchTouchInput(MultiTouchInput& aInput,
+                                      uint16_t aInputSource) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aInputSource ==
+                 mozilla::dom::MouseEvent_Binding::MOZ_SOURCE_TOUCH ||
+             aInputSource == mozilla::dom::MouseEvent_Binding::MOZ_SOURCE_PEN);
+  if (mAPZC) {
+    MOZ_ASSERT(APZThreadUtils::IsControllerThread());
+
+    APZEventResult result = mAPZC->InputBridge()->ReceiveInputEvent(aInput);
+    if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+      return;
+    }
+
+    WidgetTouchEvent event = aInput.ToWidgetEvent(this, aInputSource);
+    ProcessUntransformedAPZEvent(&event, result);
+  } else {
+    WidgetTouchEvent event = aInput.ToWidgetEvent(this, aInputSource);
+
+    nsEventStatus status;
+    DispatchEvent(&event, status);
+  }
+}
+
+void nsBaseWidget::DispatchPanGestureInput(PanGestureInput& aInput) {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mAPZC) {
+    MOZ_ASSERT(APZThreadUtils::IsControllerThread());
+
+    APZEventResult result = mAPZC->InputBridge()->ReceiveInputEvent(aInput);
+    if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+      return;
+    }
+
+    WidgetWheelEvent event = aInput.ToWidgetEvent(this);
+    ProcessUntransformedAPZEvent(&event, result);
+  } else {
+    WidgetWheelEvent event = aInput.ToWidgetEvent(this);
+    nsEventStatus status;
+    DispatchEvent(&event, status);
+  }
+}
+
+void nsBaseWidget::DispatchPinchGestureInput(PinchGestureInput& aInput) {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mAPZC) {
+    MOZ_ASSERT(APZThreadUtils::IsControllerThread());
+    APZEventResult result = mAPZC->InputBridge()->ReceiveInputEvent(aInput);
+
+    if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+      return;
+    }
+    WidgetWheelEvent event = aInput.ToWidgetEvent(this);
+    ProcessUntransformedAPZEvent(&event, result);
+  } else {
+    WidgetWheelEvent event = aInput.ToWidgetEvent(this);
+    nsEventStatus status;
+    DispatchEvent(&event, status);
+  }
+}
+
+nsIWidget::ContentAndAPZEventStatus nsBaseWidget::DispatchInputEvent(
+    WidgetInputEvent* aEvent) {
+  nsIWidget::ContentAndAPZEventStatus status;
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (mAPZC) {
+    if (APZThreadUtils::IsControllerThread()) {
+      APZEventResult result = mAPZC->InputBridge()->ReceiveInputEvent(*aEvent);
+      status.mApzStatus = result.GetStatus();
+      if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+        return status;
+      }
+      status.mContentStatus = ProcessUntransformedAPZEvent(aEvent, result);
+      return status;
+    }
+    // Most drag events aren't able to converted to MouseEvent except to
+    // eDragStart and eDragEnd.
+    const bool canDispatchToApzc =
+        !aEvent->AsDragEvent() ||
+        aEvent->AsDragEvent()->CanConvertToInputData();
+    if (canDispatchToApzc) {
+      if (WidgetWheelEvent* wheelEvent = aEvent->AsWheelEvent()) {
+        RefPtr<Runnable> r =
+            new DispatchInputOnControllerThread<ScrollWheelInput,
+                                                WidgetWheelEvent>(*wheelEvent,
+                                                                  mAPZC, this);
+        APZThreadUtils::RunOnControllerThread(std::move(r));
+        status.mContentStatus = nsEventStatus_eConsumeDoDefault;
+        return status;
+      }
+      if (WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent()) {
+        RefPtr<Runnable> r =
+            new DispatchInputOnControllerThread<MouseInput, WidgetMouseEvent>(
+                *mouseEvent, mAPZC, this);
+        APZThreadUtils::RunOnControllerThread(std::move(r));
+        status.mContentStatus = nsEventStatus_eConsumeDoDefault;
+        return status;
+      }
+      if (WidgetTouchEvent* touchEvent = aEvent->AsTouchEvent()) {
+        RefPtr<Runnable> r =
+            new DispatchInputOnControllerThread<MultiTouchInput,
+                                                WidgetTouchEvent>(*touchEvent,
+                                                                  mAPZC, this);
+        APZThreadUtils::RunOnControllerThread(std::move(r));
+        status.mContentStatus = nsEventStatus_eConsumeDoDefault;
+        return status;
+      }
+      // Allow dispatching keyboard/drag events on Gecko thread
+      // without sending them to APZ
+
+      // FIXME: APZ can handle keyboard events now, we should
+      // be sending them to APZ here
+      MOZ_ASSERT(aEvent->AsKeyboardEvent() || aEvent->AsDragEvent());
+    }
+  }
+
+  DispatchEvent(aEvent, status.mContentStatus);
+  return status;
+}
+
+void nsBaseWidget::DispatchEventToAPZOnly(mozilla::WidgetInputEvent* aEvent) {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mAPZC) {
+    if (APZThreadUtils::IsControllerThread()) {
+      mAPZC->InputBridge()->ReceiveInputEvent(*aEvent);
+      return;
+    }
+
+    if (WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent()) {
+      RefPtr<Runnable> r =
+          new DispatchInputOnControllerThread<MouseInput, WidgetMouseEvent>(
+              *mouseEvent, mAPZC, this,
+              DispatchInputOnControllerThread<MouseInput,
+                                              WidgetMouseEvent>::APZOnly::Yes);
+      APZThreadUtils::RunOnControllerThread(std::move(r));
+      return;
+    }
+
+    MOZ_ASSERT_UNREACHABLE("Not implemented yet");
+  }
+}
+
+bool nsBaseWidget::DispatchWindowEvent(WidgetGUIEvent& event) {
+  nsEventStatus status;
+  DispatchEvent(&event, status);
+  return ConvertStatus(status);
+}
+
+Document* nsBaseWidget::GetDocument() const {
+  if (mWidgetListener) {
+    if (PresShell* presShell = mWidgetListener->GetPresShell()) {
+      return presShell->GetDocument();
+    }
+  }
+  return nullptr;
+}
+
+void nsBaseWidget::CreateCompositorVsyncDispatcher() {
+  // Parent directly listens to the vsync source whereas
+  // child process communicate via IPC
+  // Should be called AFTER gfxPlatform is initialized
+  if (XRE_IsParentProcess()) {
+    if (!mCompositorVsyncDispatcherLock) {
+      mCompositorVsyncDispatcherLock =
+          MakeUnique<Mutex>("mCompositorVsyncDispatcherLock");
+    }
+    MutexAutoLock lock(*mCompositorVsyncDispatcherLock.get());
+    if (!mCompositorVsyncDispatcher) {
+      RefPtr<VsyncDispatcher> vsyncDispatcher =
+          gfxPlatform::GetPlatform()->GetGlobalVsyncDispatcher();
+      mCompositorVsyncDispatcher =
+          new CompositorVsyncDispatcher(std::move(vsyncDispatcher));
+    }
+  }
+}
+
+already_AddRefed<CompositorVsyncDispatcher>
+nsBaseWidget::GetCompositorVsyncDispatcher() {
+  MOZ_ASSERT(mCompositorVsyncDispatcherLock.get());
+
+  MutexAutoLock lock(*mCompositorVsyncDispatcherLock.get());
+  RefPtr<CompositorVsyncDispatcher> dispatcher = mCompositorVsyncDispatcher;
+  return dispatcher.forget();
+}
+
+already_AddRefed<WebRenderLayerManager> nsBaseWidget::CreateCompositorSession(
+    int aWidth, int aHeight, CompositorOptions* aOptionsOut) {
+  MOZ_ASSERT(aOptionsOut);
+
+  do {
+    CreateCompositorVsyncDispatcher();
+
+    gfx::GPUProcessManager* gpu = gfx::GPUProcessManager::Get();
+    // Make sure GPU process is ready for use.
+    // If it failed to connect to GPU process, GPU process usage is disabled in
+    // EnsureGPUReady(). It could update gfxVars and gfxConfigs.
+    nsresult rv = gpu->EnsureGPUReady();
+    if (NS_WARN_IF(rv == NS_ERROR_ILLEGAL_DURING_SHUTDOWN)) {
+      return nullptr;
+    }
+
+    // If widget type does not supports acceleration, we may be allowed to use
+    // software WebRender instead.
+    bool supportsAcceleration = WidgetTypeSupportsAcceleration();
+    bool enableSWWR = true;
+    if (supportsAcceleration ||
+        StaticPrefs::gfx_webrender_unaccelerated_widget_force()) {
+      enableSWWR = gfx::gfxVars::UseSoftwareWebRender();
+    }
+    bool enableAPZ = UseAPZ();
+    CompositorOptions options(enableAPZ, enableSWWR);
+
+#ifdef XP_WIN
+    if (supportsAcceleration) {
+      options.SetAllowSoftwareWebRenderD3D11(
+          gfx::gfxVars::AllowSoftwareWebRenderD3D11());
+    }
+    if (mNeedFastSnaphot) {
+      options.SetNeedFastSnaphot(true);
+    }
+#elif defined(MOZ_WIDGET_ANDROID)
+    MOZ_ASSERT(supportsAcceleration);
+    options.SetAllowSoftwareWebRenderOGL(
+        gfx::gfxVars::AllowSoftwareWebRenderOGL());
+#elif defined(MOZ_WIDGET_GTK)
+    if (supportsAcceleration) {
+      options.SetAllowSoftwareWebRenderOGL(
+          gfx::gfxVars::AllowSoftwareWebRenderOGL());
+    }
+#endif
+
+#ifdef MOZ_WIDGET_ANDROID
+    // Unconditionally set the compositor as initially paused, as we have not
+    // yet had a chance to send the compositor surface to the GPU process. We
+    // will do so shortly once we have returned to nsWindow::CreateLayerManager,
+    // where we will also resume the compositor if required.
+    options.SetInitiallyPaused(true);
+#else
+    options.SetInitiallyPaused(CompositorInitiallyPaused());
+#endif
+
+    RefPtr<WebRenderLayerManager> lm = new WebRenderLayerManager(this);
+
+    uint64_t innerWindowId = 0;
+    if (Document* doc = GetDocument()) {
+      innerWindowId = doc->InnerWindowID();
+    }
+
+    bool retry = false;
+    mCompositorSession = gpu->CreateTopLevelCompositor(
+        this, lm, GetDefaultScale(), options, UseExternalCompositingSurface(),
+        gfx::IntSize(aWidth, aHeight), innerWindowId, &retry);
+
+    if (mCompositorSession) {
+      TextureFactoryIdentifier textureFactoryIdentifier;
+      nsCString error;
+      lm->Initialize(mCompositorSession->GetCompositorBridgeChild(),
+                     wr::AsPipelineId(mCompositorSession->RootLayerTreeId()),
+                     &textureFactoryIdentifier, error);
+      if (textureFactoryIdentifier.mParentBackend != LayersBackend::LAYERS_WR) {
+        retry = true;
+        DestroyCompositor();
+        // gfxVars::UseDoubleBufferingWithCompositor() is also disabled.
+        gfx::GPUProcessManager::Get()->DisableWebRender(
+            wr::WebRenderError::INITIALIZE, error);
+      }
+    }
+
+    // We need to retry in a loop because the act of failing to create the
+    // compositor can change our state (e.g. disable WebRender).
+    if (mCompositorSession || !retry) {
+      *aOptionsOut = options;
+      return lm.forget();
+    }
+  } while (true);
+}
+
+void nsBaseWidget::CreateCompositor(int aWidth, int aHeight) {
+  // This makes sure that gfxPlatforms gets initialized if it hasn't by now.
+  gfxPlatform::GetPlatform();
+
+  MOZ_ASSERT(gfxPlatform::UsesOffMainThreadCompositing(),
+             "This function assumes OMTC");
+
+  MOZ_ASSERT(!mCompositorSession && !mCompositorBridgeChild,
+             "Should have properly cleaned up the previous PCompositor pair "
+             "beforehand");
+
+  if (mCompositorBridgeChild) {
+    mCompositorBridgeChild->Destroy();
+  }
+
+  // Recreating this is tricky, as we may still have an old and we need
+  // to make sure it's properly destroyed by calling DestroyCompositor!
+
+  // If we've already received a shutdown notification, don't try
+  // create a new compositor.
+  if (!mShutdownObserver) {
+    return;
+  }
+
+  // The controller thread must be configured before the compositor
+  // session is created, so that the input bridge runs on the right
+  // thread.
+  ConfigureAPZControllerThread();
+
+  CompositorOptions options;
+  RefPtr<WebRenderLayerManager> lm =
+      CreateCompositorSession(aWidth, aHeight, &options);
+  if (!lm) {
+    return;
+  }
+
+  MOZ_ASSERT(mCompositorSession);
+  mCompositorBridgeChild = mCompositorSession->GetCompositorBridgeChild();
+  SetCompositorWidgetDelegate(
+      mCompositorSession->GetCompositorWidgetDelegate());
+
+  if (options.UseAPZ()) {
+    mAPZC = mCompositorSession->GetAPZCTreeManager();
+    ConfigureAPZCTreeManager();
+  } else {
+    mAPZC = nullptr;
+  }
+
+  if (mInitialZoomConstraints) {
+    UpdateZoomConstraints(mInitialZoomConstraints->mPresShellID,
+                          mInitialZoomConstraints->mViewID,
+                          Some(mInitialZoomConstraints->mConstraints));
+    mInitialZoomConstraints.reset();
+  }
+
+  TextureFactoryIdentifier textureFactoryIdentifier =
+      lm->GetTextureFactoryIdentifier();
+  MOZ_ASSERT(textureFactoryIdentifier.mParentBackend ==
+             LayersBackend::LAYERS_WR);
+  ImageBridgeChild::IdentifyCompositorTextureHost(textureFactoryIdentifier);
+  gfx::VRManagerChild::IdentifyTextureHost(textureFactoryIdentifier);
+
+  WindowUsesOMTC();
+
+  mWindowRenderer = std::move(lm);
+
+  // Only track compositors for top-level windows, since other window types
+  // may use the basic compositor.  Except on the OS X - see bug 1306383
+#if defined(XP_MACOSX)
+  bool getCompositorFromThisWindow = true;
+#else
+  bool getCompositorFromThisWindow = mWindowType == WindowType::TopLevel;
+#endif
+
+  if (getCompositorFromThisWindow) {
+    gfxPlatform::GetPlatform()->NotifyCompositorCreated(
+        mWindowRenderer->GetCompositorBackendType());
+  }
+}
+
+void nsBaseWidget::NotifyCompositorSessionLost(CompositorSession* aSession) {
+  MOZ_ASSERT(aSession == mCompositorSession);
+  DestroyLayerManager();
+}
+
+bool nsBaseWidget::ShouldUseOffMainThreadCompositing() {
+  return gfxPlatform::UsesOffMainThreadCompositing();
+}
+
+WindowRenderer* nsBaseWidget::GetWindowRenderer() {
+  if (!mWindowRenderer) {
+    if (!mShutdownObserver) {
+      // We are shutting down, do not try to re-create a LayerManager
+      return nullptr;
+    }
+    // Try to use an async compositor first, if possible
+    if (ShouldUseOffMainThreadCompositing()) {
+      CreateCompositor();
+    }
+
+    if (!mWindowRenderer) {
+      mWindowRenderer = CreateFallbackRenderer();
+    }
+  }
+  return mWindowRenderer;
+}
+
+WindowRenderer* nsBaseWidget::CreateFallbackRenderer() {
+  return new FallbackRenderer;
+}
+
+CompositorBridgeChild* nsBaseWidget::GetRemoteRenderer() {
+  return mCompositorBridgeChild;
+}
+
+void nsBaseWidget::ClearCachedWebrenderResources() {
+  if (!mWindowRenderer || !mWindowRenderer->AsWebRender()) {
+    return;
+  }
+  mWindowRenderer->AsWebRender()->ClearCachedResources();
+}
+
+void nsBaseWidget::ClearWebrenderAnimationResources() {
+  if (!mWindowRenderer || !mWindowRenderer->AsWebRender()) {
+    return;
+  }
+  mWindowRenderer->AsWebRender()->ClearAnimationResources();
+}
+
+bool nsBaseWidget::SetNeedFastSnaphot() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(!mCompositorSession);
+
+  if (!XRE_IsParentProcess() || mCompositorSession) {
+    return false;
+  }
+
+  mNeedFastSnaphot = true;
+  return true;
+}
+
+already_AddRefed<gfx::DrawTarget> nsBaseWidget::StartRemoteDrawing() {
+  return nullptr;
+}
+
+uint32_t nsBaseWidget::GetGLFrameBufferFormat() { return LOCAL_GL_RGBA; }
+
+//-------------------------------------------------------------------------
+//
+// Destroy the window
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::OnDestroy() {
+  if (mTextEventDispatcher) {
+    mTextEventDispatcher->OnDestroyWidget();
+    // Don't release it until this widget actually released because after this
+    // is called, TextEventDispatcher() may create it again.
+  }
+
+  // If this widget is being destroyed, let the APZ code know to drop references
+  // to this widget. Callers of this function all should be holding a deathgrip
+  // on this widget already.
+  ReleaseContentController();
+}
+
+void nsBaseWidget::MoveClient(const DesktopPoint& aOffset) {
+  LayoutDeviceIntPoint clientOffset(GetClientOffset());
+
+  // GetClientOffset returns device pixels; scale back to desktop pixels
+  // if that's what this widget uses for the Move/Resize APIs
+  if (BoundsUseDesktopPixels()) {
+    DesktopPoint desktopOffset = clientOffset / GetDesktopToDeviceScale();
+    Move(aOffset.x - desktopOffset.x, aOffset.y - desktopOffset.y);
+  } else {
+    LayoutDevicePoint layoutOffset = aOffset * GetDesktopToDeviceScale();
+    Move(layoutOffset.x - LayoutDeviceCoord(clientOffset.x),
+         layoutOffset.y - LayoutDeviceCoord(clientOffset.y));
+  }
+}
+
+void nsBaseWidget::ResizeClient(const DesktopSize& aSize, bool aRepaint) {
+  NS_ASSERTION((aSize.width >= 0), "Negative width passed to ResizeClient");
+  NS_ASSERTION((aSize.height >= 0), "Negative height passed to ResizeClient");
+
+  LayoutDeviceIntRect clientBounds = GetClientBounds();
+
+  // GetClientBounds and mBounds are device pixels; scale back to desktop pixels
+  // if that's what this widget uses for the Move/Resize APIs
+  if (BoundsUseDesktopPixels()) {
+    DesktopSize desktopDelta =
+        (LayoutDeviceIntSize(mBounds.Width(), mBounds.Height()) -
+         clientBounds.Size()) /
+        GetDesktopToDeviceScale();
+    Resize(aSize.width + desktopDelta.width, aSize.height + desktopDelta.height,
+           aRepaint);
+  } else {
+    LayoutDeviceSize layoutSize = aSize * GetDesktopToDeviceScale();
+    Resize(mBounds.Width() + (layoutSize.width - clientBounds.Width()),
+           mBounds.Height() + (layoutSize.height - clientBounds.Height()),
+           aRepaint);
+  }
+}
+
+void nsBaseWidget::ResizeClient(const DesktopRect& aRect, bool aRepaint) {
+  NS_ASSERTION((aRect.Width() >= 0), "Negative width passed to ResizeClient");
+  NS_ASSERTION((aRect.Height() >= 0), "Negative height passed to ResizeClient");
+
+  LayoutDeviceIntRect clientBounds = GetClientBounds();
+  LayoutDeviceIntPoint clientOffset = GetClientOffset();
+  DesktopToLayoutDeviceScale scale = GetDesktopToDeviceScale();
+
+  if (BoundsUseDesktopPixels()) {
+    DesktopPoint desktopOffset = clientOffset / scale;
+    DesktopSize desktopDelta =
+        (LayoutDeviceIntSize(mBounds.Width(), mBounds.Height()) -
+         clientBounds.Size()) /
+        scale;
+    Resize(aRect.X() - desktopOffset.x, aRect.Y() - desktopOffset.y,
+           aRect.Width() + desktopDelta.width,
+           aRect.Height() + desktopDelta.height, aRepaint);
+  } else {
+    LayoutDeviceRect layoutRect = aRect * scale;
+    Resize(layoutRect.X() - clientOffset.x, layoutRect.Y() - clientOffset.y,
+           layoutRect.Width() + mBounds.Width() - clientBounds.Width(),
+           layoutRect.Height() + mBounds.Height() - clientBounds.Height(),
+           aRepaint);
+  }
+}
+
+//-------------------------------------------------------------------------
+//
+// Bounds
+//
+//-------------------------------------------------------------------------
+
+/**
+ * If the implementation of nsWindow supports borders this method MUST be
+ * overridden
+ *
+ **/
+LayoutDeviceIntRect nsBaseWidget::GetClientBounds() { return GetBounds(); }
+
+/**
+ * If the implementation of nsWindow supports borders this method MUST be
+ * overridden
+ *
+ **/
+LayoutDeviceIntRect nsBaseWidget::GetBounds() { return mBounds; }
+
+/**
+ * If the implementation of nsWindow uses a local coordinate system within the
+ *window, this method must be overridden
+ *
+ **/
+LayoutDeviceIntRect nsBaseWidget::GetScreenBounds() { return GetBounds(); }
+
+nsresult nsBaseWidget::GetRestoredBounds(LayoutDeviceIntRect& aRect) {
+  if (SizeMode() != nsSizeMode_Normal) {
+    return NS_ERROR_FAILURE;
+  }
+  aRect = GetScreenBounds();
+  return NS_OK;
+}
+
+LayoutDeviceIntPoint nsBaseWidget::GetClientOffset() {
+  return LayoutDeviceIntPoint(0, 0);
+}
+
+nsresult nsBaseWidget::SetNonClientMargins(const LayoutDeviceIntMargin&) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+void nsBaseWidget::SetResizeMargin(LayoutDeviceIntCoord aResizeMargin) {}
+
+uint32_t nsBaseWidget::GetMaxTouchPoints() const { return 0; }
+
+bool nsBaseWidget::HasPendingInputEvent() { return false; }
+
+bool nsBaseWidget::ShowsResizeIndicator(LayoutDeviceIntRect* aResizerRect) {
+  return false;
+}
+
+/**
+ * Modifies aFile to point at an icon file with the given name and suffix.  The
+ * suffix may correspond to a file extension with leading '.' if appropriate.
+ * Returns true if the icon file exists and can be read.
+ */
+static bool ResolveIconNameHelper(nsIFile* aFile, const nsAString& aIconName,
+                                  const nsAString& aIconSuffix) {
+  aFile->Append(u"icons"_ns);
+  aFile->Append(u"default"_ns);
+  aFile->Append(aIconName + aIconSuffix);
+
+  bool readable;
+  return NS_SUCCEEDED(aFile->IsReadable(&readable)) && readable;
+}
+
+/**
+ * Resolve the given icon name into a local file object.  This method is
+ * intended to be called by subclasses of nsBaseWidget.  aIconSuffix is a
+ * platform specific icon file suffix (e.g., ".ico" under Win32).
+ *
+ * If no file is found matching the given parameters, then null is returned.
+ */
+void nsBaseWidget::ResolveIconName(const nsAString& aIconName,
+                                   const nsAString& aIconSuffix,
+                                   nsIFile** aResult) {
+  *aResult = nullptr;
+
+  nsCOMPtr<nsIProperties> dirSvc =
+      do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID);
+  if (!dirSvc) return;
+
+  // first check auxilary chrome directories
+
+  nsCOMPtr<nsISimpleEnumerator> dirs;
+  dirSvc->Get(NS_APP_CHROME_DIR_LIST, NS_GET_IID(nsISimpleEnumerator),
+              getter_AddRefs(dirs));
+  if (dirs) {
+    bool hasMore;
+    while (NS_SUCCEEDED(dirs->HasMoreElements(&hasMore)) && hasMore) {
+      nsCOMPtr<nsISupports> element;
+      dirs->GetNext(getter_AddRefs(element));
+      if (!element) continue;
+      nsCOMPtr<nsIFile> file = do_QueryInterface(element);
+      if (!file) continue;
+      if (ResolveIconNameHelper(file, aIconName, aIconSuffix)) {
+        NS_ADDREF(*aResult = file);
+        return;
+      }
+    }
+  }
+
+  // then check the main app chrome directory
+
+  nsCOMPtr<nsIFile> file;
+  dirSvc->Get(NS_APP_CHROME_DIR, NS_GET_IID(nsIFile), getter_AddRefs(file));
+  if (file && ResolveIconNameHelper(file, aIconName, aIconSuffix))
+    NS_ADDREF(*aResult = file);
+}
+
+void nsBaseWidget::SetSizeConstraints(const SizeConstraints& aConstraints) {
+  mSizeConstraints = aConstraints;
+
+  // Popups are constrained during layout, and we don't want to synchronously
+  // paint from reflow, so bail out... This is not great, but it's no worse than
+  // what we used to do.
+  //
+  // The right fix here is probably making constraint changes go through the
+  // view manager and such.
+  if (mWindowType == WindowType::Popup) {
+    return;
+  }
+
+  // If the current size doesn't meet the new constraints, trigger a
+  // resize to apply it. Note that, we don't want to invoke Resize if
+  // the new constraints don't affect the current size, because Resize
+  // implementation on some platforms may touch other geometry even if
+  // the size don't need to change.
+  LayoutDeviceIntSize curSize = mBounds.Size();
+  LayoutDeviceIntSize clampedSize =
+      Max(aConstraints.mMinSize, Min(aConstraints.mMaxSize, curSize));
+  if (clampedSize != curSize) {
+    gfx::Size size;
+    if (BoundsUseDesktopPixels()) {
+      DesktopSize desktopSize = clampedSize / GetDesktopToDeviceScale();
+      size = desktopSize.ToUnknownSize();
+    } else {
+      size = gfx::Size(clampedSize.ToUnknownSize());
+    }
+    Resize(size.width, size.height, true);
+  }
+}
+
+const widget::SizeConstraints nsBaseWidget::GetSizeConstraints() {
+  return mSizeConstraints;
+}
+
+// static
+nsIRollupListener* nsBaseWidget::GetActiveRollupListener() {
+  // TODO: Simplify this.
+  return nsXULPopupManager::GetInstance();
+}
+
+void nsBaseWidget::NotifyWindowDestroyed() {
+  if (!mWidgetListener) return;
+
+  nsCOMPtr<nsIAppWindow> window = mWidgetListener->GetAppWindow();
+  nsCOMPtr<nsIBaseWindow> appWindow(do_QueryInterface(window));
+  if (appWindow) {
+    appWindow->Destroy();
+  }
+}
+
+void nsBaseWidget::NotifyWindowMoved(int32_t aX, int32_t aY,
+                                     ByMoveToRect aByMoveToRect) {
+  if (mWidgetListener) {
+    mWidgetListener->WindowMoved(this, aX, aY, aByMoveToRect);
+  }
+
+  if (mIMEHasFocus && IMENotificationRequestsRef().WantPositionChanged()) {
+    NotifyIME(IMENotification(IMEMessage::NOTIFY_IME_OF_POSITION_CHANGE));
+  }
+}
+
+void nsBaseWidget::NotifySizeMoveDone() {
+  if (!mWidgetListener) {
+    return;
+  }
+  if (PresShell* presShell = mWidgetListener->GetPresShell()) {
+    presShell->WindowSizeMoveDone();
+  }
+}
+
+void nsBaseWidget::NotifyThemeChanged(ThemeChangeKind aKind) {
+  LookAndFeel::NotifyChangedAllWindows(aKind);
+}
+
+nsresult nsBaseWidget::NotifyIME(const IMENotification& aIMENotification) {
+  if (mIMEHasQuit) {
+    return NS_OK;
+  }
+  switch (aIMENotification.mMessage) {
+    case REQUEST_TO_COMMIT_COMPOSITION:
+    case REQUEST_TO_CANCEL_COMPOSITION:
+      // We should send request to IME only when there is a TextEventDispatcher
+      // instance (this means that this widget has dispatched at least one
+      // composition event or keyboard event) and the it has composition.
+      // Otherwise, there is nothing to do.
+      // Note that if current input transaction is for native input events,
+      // TextEventDispatcher::NotifyIME() will call
+      // TextEventDispatcherListener::NotifyIME().
+      if (mTextEventDispatcher && mTextEventDispatcher->IsComposing()) {
+        return mTextEventDispatcher->NotifyIME(aIMENotification);
+      }
+      return NS_OK;
+    default: {
+      if (aIMENotification.mMessage == NOTIFY_IME_OF_FOCUS) {
+        mIMEHasFocus = true;
+      }
+      EnsureTextEventDispatcher();
+      // TextEventDispatcher::NotifyIME() will always call
+      // TextEventDispatcherListener::NotifyIME().  I.e., even if current
+      // input transaction is for synthesized events for automated tests,
+      // notifications will be sent to native IME.
+      nsresult rv = mTextEventDispatcher->NotifyIME(aIMENotification);
+      if (aIMENotification.mMessage == NOTIFY_IME_OF_BLUR) {
+        mIMEHasFocus = false;
+      }
+      return rv;
+    }
+  }
+}
+
+void nsBaseWidget::EnsureTextEventDispatcher() {
+  if (mTextEventDispatcher) {
+    return;
+  }
+  mTextEventDispatcher = new TextEventDispatcher(this);
+}
+
+nsIWidget::NativeIMEContext nsBaseWidget::GetNativeIMEContext() {
+  if (mTextEventDispatcher && mTextEventDispatcher->GetPseudoIMEContext()) {
+    // If we already have a TextEventDispatcher and it's working with
+    // a TextInputProcessor, we need to return pseudo IME context since
+    // TextCompositionArray::IndexOf(nsIWidget*) should return a composition
+    // on the pseudo IME context in such case.
+    NativeIMEContext pseudoIMEContext;
+    pseudoIMEContext.InitWithRawNativeIMEContext(
+        mTextEventDispatcher->GetPseudoIMEContext());
+    return pseudoIMEContext;
+  }
+  return NativeIMEContext(this);
+}
+
+nsIWidget::TextEventDispatcher* nsBaseWidget::GetTextEventDispatcher() {
+  EnsureTextEventDispatcher();
+  return mTextEventDispatcher;
+}
+
+void* nsBaseWidget::GetPseudoIMEContext() {
+  TextEventDispatcher* dispatcher = GetTextEventDispatcher();
+  if (!dispatcher) {
+    return nullptr;
+  }
+  return dispatcher->GetPseudoIMEContext();
+}
+
+TextEventDispatcherListener*
+nsBaseWidget::GetNativeTextEventDispatcherListener() {
+  // TODO: If all platforms supported use of TextEventDispatcher for handling
+  //       native IME and keyboard events, this method should be removed since
+  //       in such case, this is overridden by all the subclasses.
+  return nullptr;
+}
+
+void nsBaseWidget::ZoomToRect(const uint32_t& aPresShellId,
+                              const ScrollableLayerGuid::ViewID& aViewId,
+                              const CSSRect& aRect, const uint32_t& aFlags) {
+  if (!mCompositorSession || !mAPZC) {
+    return;
+  }
+  LayersId layerId = mCompositorSession->RootLayerTreeId();
+  mAPZC->ZoomToRect(ScrollableLayerGuid(layerId, aPresShellId, aViewId),
+                    ZoomTarget{aRect}, aFlags);
+}
+
+#ifdef ACCESSIBILITY
+
+a11y::LocalAccessible* nsBaseWidget::GetRootAccessible() {
+  NS_ENSURE_TRUE(mWidgetListener, nullptr);
+
+  PresShell* presShell = mWidgetListener->GetPresShell();
+  NS_ENSURE_TRUE(presShell, nullptr);
+
+  // If container is null then the presshell is not active. This often happens
+  // when a preshell is being held onto for fastback.
+  nsPresContext* presContext = presShell->GetPresContext();
+  NS_ENSURE_TRUE(presContext->GetContainerWeak(), nullptr);
+
+  // LocalAccessible creation might be not safe so use IsSafeToRunScript to
+  // make sure it's not created at unsafe times.
+  nsAccessibilityService* accService = GetOrCreateAccService();
+  if (accService) {
+    return accService->GetRootDocumentAccessible(
+        presShell, nsContentUtils::IsSafeToRunScript());
+  }
+
+  return nullptr;
+}
+
+#endif  // ACCESSIBILITY
+
+void nsBaseWidget::StartAsyncScrollbarDrag(
+    const AsyncDragMetrics& aDragMetrics) {
+  if (!AsyncPanZoomEnabled()) {
+    return;
+  }
+
+  MOZ_ASSERT(XRE_IsParentProcess() && mCompositorSession);
+
+  LayersId layersId = mCompositorSession->RootLayerTreeId();
+  ScrollableLayerGuid guid(layersId, aDragMetrics.mPresShellId,
+                           aDragMetrics.mViewId);
+
+  mAPZC->StartScrollbarDrag(guid, aDragMetrics);
+}
+
+bool nsBaseWidget::StartAsyncAutoscroll(const ScreenPoint& aAnchorLocation,
+                                        const ScrollableLayerGuid& aGuid) {
+  MOZ_ASSERT(XRE_IsParentProcess() && AsyncPanZoomEnabled());
+
+  return mAPZC->StartAutoscroll(aGuid, aAnchorLocation);
+}
+
+void nsBaseWidget::StopAsyncAutoscroll(const ScrollableLayerGuid& aGuid) {
+  MOZ_ASSERT(XRE_IsParentProcess() && AsyncPanZoomEnabled());
+
+  mAPZC->StopAutoscroll(aGuid);
+}
+
+LayersId nsBaseWidget::GetRootLayerTreeId() {
+  return mCompositorSession ? mCompositorSession->RootLayerTreeId()
+                            : LayersId{0};
+}
+
+already_AddRefed<widget::Screen> nsBaseWidget::GetWidgetScreen() {
+  ScreenManager& screenManager = ScreenManager::GetSingleton();
+  LayoutDeviceIntRect bounds = GetScreenBounds();
+  DesktopIntRect deskBounds = RoundedToInt(bounds / GetDesktopToDeviceScale());
+  return screenManager.ScreenForRect(deskBounds);
+}
+
+mozilla::DesktopToLayoutDeviceScale
+nsBaseWidget::GetDesktopToDeviceScaleByScreen() {
+  return (nsView::GetViewFor(this)->GetViewManager()->GetDeviceContext())
+      ->GetDesktopToDeviceScale();
+}
+
+nsresult nsIWidget::SynthesizeNativeTouchTap(LayoutDeviceIntPoint aPoint,
+                                             bool aLongTap,
+                                             nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchtap");
+
+  if (sPointerIdCounter > TOUCH_INJECT_MAX_POINTS) {
+    sPointerIdCounter = 0;
+  }
+  int pointerId = sPointerIdCounter;
+  sPointerIdCounter++;
+  nsresult rv = SynthesizeNativeTouchPoint(pointerId, TOUCH_CONTACT, aPoint,
+                                           1.0, 90, nullptr);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  if (!aLongTap) {
+    return SynthesizeNativeTouchPoint(pointerId, TOUCH_REMOVE, aPoint, 0, 0,
+                                      nullptr);
+  }
+
+  // initiate a long tap
+  int elapse = Preferences::GetInt("ui.click_hold_context_menus.delay",
+                                   TOUCH_INJECT_LONG_TAP_DEFAULT_MSEC);
+  if (!mLongTapTimer) {
+    mLongTapTimer = NS_NewTimer();
+    if (!mLongTapTimer) {
+      SynthesizeNativeTouchPoint(pointerId, TOUCH_CANCEL, aPoint, 0, 0,
+                                 nullptr);
+      return NS_ERROR_UNEXPECTED;
+    }
+    // Windows requires recuring events, so we set this to a smaller window
+    // than the pref value.
+    int timeout = elapse;
+    if (timeout > TOUCH_INJECT_PUMP_TIMER_MSEC) {
+      timeout = TOUCH_INJECT_PUMP_TIMER_MSEC;
+    }
+    mLongTapTimer->InitWithNamedFuncCallback(
+        OnLongTapTimerCallback, this, timeout, nsITimer::TYPE_REPEATING_SLACK,
+        "nsIWidget::SynthesizeNativeTouchTap");
+  }
+
+  // If we already have a long tap pending, cancel it. We only allow one long
+  // tap to be active at a time.
+  if (mLongTapTouchPoint) {
+    SynthesizeNativeTouchPoint(mLongTapTouchPoint->mPointerId, TOUCH_CANCEL,
+                               mLongTapTouchPoint->mPosition, 0, 0, nullptr);
+  }
+
+  mLongTapTouchPoint = MakeUnique<LongTapInfo>(
+      pointerId, aPoint, TimeDuration::FromMilliseconds(elapse), aObserver);
+  notifier.SkipNotification();  // we'll do it in the long-tap callback
+  return NS_OK;
+}
+
+// static
+void nsIWidget::OnLongTapTimerCallback(nsITimer* aTimer, void* aClosure) {
+  auto* self = static_cast<nsIWidget*>(aClosure);
+
+  if ((self->mLongTapTouchPoint->mStamp + self->mLongTapTouchPoint->mDuration) >
+      TimeStamp::Now()) {
+#ifdef XP_WIN
+    // Windows needs us to keep pumping feedback to the digitizer, so update
+    // the pointer id with the same position.
+    self->SynthesizeNativeTouchPoint(
+        self->mLongTapTouchPoint->mPointerId, TOUCH_CONTACT,
+        self->mLongTapTouchPoint->mPosition, 1.0, 90, nullptr);
+#endif
+    return;
+  }
+
+  AutoObserverNotifier notifier(self->mLongTapTouchPoint->mObserver,
+                                "touchtap");
+
+  // finished, remove the touch point
+  self->mLongTapTimer->Cancel();
+  self->mLongTapTimer = nullptr;
+  self->SynthesizeNativeTouchPoint(
+      self->mLongTapTouchPoint->mPointerId, TOUCH_REMOVE,
+      self->mLongTapTouchPoint->mPosition, 0, 0, nullptr);
+  self->mLongTapTouchPoint = nullptr;
+}
+
+float nsIWidget::GetFallbackDPI() {
+  RefPtr<const Screen> primaryScreen =
+      ScreenManager::GetSingleton().GetPrimaryScreen();
+  return primaryScreen->GetDPI();
+}
+
+CSSToLayoutDeviceScale nsIWidget::GetFallbackDefaultScale() {
+  RefPtr<const Screen> s = ScreenManager::GetSingleton().GetPrimaryScreen();
+  return s->GetCSSToLayoutDeviceScale(Screen::IncludeOSZoom::No);
+}
+
+nsresult nsIWidget::ClearNativeTouchSequence(nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "cleartouch");
+
+  // XXX This is odd.  This is called by the constructor of nsIWidget.  However,
+  //     at that point, nsIWidget::mLongTapTimer must be nullptr.  Therefore,
+  //     this must do nothing at initializing the instance.
+  if (!mLongTapTimer) {
+    return NS_OK;
+  }
+  mLongTapTimer->Cancel();
+  mLongTapTimer = nullptr;
+  SynthesizeNativeTouchPoint(mLongTapTouchPoint->mPointerId, TOUCH_CANCEL,
+                             mLongTapTouchPoint->mPosition, 0, 0, nullptr);
+  mLongTapTouchPoint = nullptr;
+  return NS_OK;
+}
+
+MultiTouchInput nsBaseWidget::UpdateSynthesizedTouchState(
+    MultiTouchInput* aState, mozilla::TimeStamp aTimeStamp, uint32_t aPointerId,
+    TouchPointerState aPointerState, LayoutDeviceIntPoint aPoint,
+    double aPointerPressure, uint32_t aPointerOrientation) {
+  ScreenIntPoint pointerScreenPoint = ViewAs<ScreenPixel>(
+      aPoint, PixelCastJustification::LayoutDeviceIsScreenForBounds);
+
+  // We can't dispatch *aState directly because (a) dispatching
+  // it might inadvertently modify it and (b) in the case of touchend or
+  // touchcancel events aState will hold the touches that are
+  // still down whereas the input dispatched needs to hold the removed
+  // touch(es). We use |inputToDispatch| for this purpose.
+  MultiTouchInput inputToDispatch;
+  inputToDispatch.mInputType = MULTITOUCH_INPUT;
+  inputToDispatch.mTimeStamp = aTimeStamp;
+
+  int32_t index = aState->IndexOfTouch((int32_t)aPointerId);
+  if (aPointerState == TOUCH_CONTACT) {
+    if (index >= 0) {
+      // found an existing touch point, update it
+      SingleTouchData& point = aState->mTouches[index];
+      point.mScreenPoint = pointerScreenPoint;
+      point.mRotationAngle = (float)aPointerOrientation;
+      point.mForce = (float)aPointerPressure;
+      inputToDispatch.mType = MultiTouchInput::MULTITOUCH_MOVE;
+    } else {
+      // new touch point, add it
+      aState->mTouches.AppendElement(SingleTouchData(
+          (int32_t)aPointerId, pointerScreenPoint, ScreenSize(0, 0),
+          (float)aPointerOrientation, (float)aPointerPressure));
+      inputToDispatch.mType = MultiTouchInput::MULTITOUCH_START;
+    }
+    inputToDispatch.mTouches = aState->mTouches;
+  } else {
+    MOZ_ASSERT(aPointerState == TOUCH_REMOVE || aPointerState == TOUCH_CANCEL);
+    // a touch point is being lifted, so remove it from the stored list
+    if (index >= 0) {
+      aState->mTouches.RemoveElementAt(index);
+    }
+    inputToDispatch.mType =
+        (aPointerState == TOUCH_REMOVE ? MultiTouchInput::MULTITOUCH_END
+                                       : MultiTouchInput::MULTITOUCH_CANCEL);
+    inputToDispatch.mTouches.AppendElement(SingleTouchData(
+        (int32_t)aPointerId, pointerScreenPoint, ScreenSize(0, 0),
+        (float)aPointerOrientation, (float)aPointerPressure));
+  }
+
+  return inputToDispatch;
+}
+
+void nsBaseWidget::NotifyLiveResizeStarted() {
+  // If we have mLiveResizeListeners already non-empty, we should notify those
+  // listeners that the resize stopped before starting anew. In theory this
+  // should never happen because we shouldn't get nested live resize actions.
+  NotifyLiveResizeStopped();
+  MOZ_ASSERT(mLiveResizeListeners.IsEmpty());
+
+  // If we can get the active remote tab for the current widget, suppress
+  // the displayport on it during the live resize.
+  if (!mWidgetListener) {
+    return;
+  }
+  nsCOMPtr<nsIAppWindow> appWindow = mWidgetListener->GetAppWindow();
+  if (!appWindow) {
+    return;
+  }
+  mLiveResizeListeners = appWindow->GetLiveResizeListeners();
+  for (uint32_t i = 0; i < mLiveResizeListeners.Length(); i++) {
+    mLiveResizeListeners[i]->LiveResizeStarted();
+  }
+}
+
+void nsBaseWidget::NotifyLiveResizeStopped() {
+  if (!mLiveResizeListeners.IsEmpty()) {
+    for (uint32_t i = 0; i < mLiveResizeListeners.Length(); i++) {
+      mLiveResizeListeners[i]->LiveResizeStopped();
+    }
+    mLiveResizeListeners.Clear();
+  }
+}
+
+nsresult nsBaseWidget::AsyncEnableDragDrop(bool aEnable) {
+  RefPtr<nsBaseWidget> kungFuDeathGrip = this;
+  return NS_DispatchToCurrentThreadQueue(
+      NS_NewRunnableFunction(
+          "AsyncEnableDragDropFn",
+          [this, aEnable, kungFuDeathGrip]() { EnableDragDrop(aEnable); }),
+      kAsyncDragDropTimeout, EventQueuePriority::Idle);
+}
+
+void nsBaseWidget::SwipeFinished() {
+  if (mSwipeTracker) {
+    mSwipeTracker->Destroy();
+    mSwipeTracker = nullptr;
+  }
+}
+
+void nsBaseWidget::ReportSwipeStarted(uint64_t aInputBlockId,
+                                      bool aStartSwipe) {
+  if (mSwipeEventQueue && mSwipeEventQueue->inputBlockId == aInputBlockId) {
+    if (aStartSwipe) {
+      PanGestureInput& startEvent = mSwipeEventQueue->queuedEvents[0];
+      TrackScrollEventAsSwipe(startEvent, mSwipeEventQueue->allowedDirections,
+                              aInputBlockId);
+      for (size_t i = 1; i < mSwipeEventQueue->queuedEvents.Length(); i++) {
+        mSwipeTracker->ProcessEvent(mSwipeEventQueue->queuedEvents[i]);
+      }
+    } else if (mAPZC) {
+      // If the event wasn't start swipe, we need to notify it to APZ.
+      mAPZC->SetBrowserGestureResponse(aInputBlockId,
+                                       BrowserGestureResponse::NotConsumed);
+    }
+    mSwipeEventQueue = nullptr;
+  }
+}
+
+void nsBaseWidget::TrackScrollEventAsSwipe(
+    const mozilla::PanGestureInput& aSwipeStartEvent,
+    uint32_t aAllowedDirections, uint64_t aInputBlockId) {
+  // If a swipe is currently being tracked kill it -- it's been interrupted
+  // by another gesture event.
+  if (mSwipeTracker) {
+    mSwipeTracker->CancelSwipe(aSwipeStartEvent.mTimeStamp);
+    mSwipeTracker->Destroy();
+    mSwipeTracker = nullptr;
+  }
+
+  uint32_t direction =
+      (aSwipeStartEvent.mPanDisplacement.x > 0.0)
+          ? (uint32_t)dom::SimpleGestureEvent_Binding::DIRECTION_RIGHT
+          : (uint32_t)dom::SimpleGestureEvent_Binding::DIRECTION_LEFT;
+
+  mSwipeTracker =
+      new SwipeTracker(*this, aSwipeStartEvent, aAllowedDirections, direction);
+
+  if (!mAPZC) {
+    mCurrentPanGestureBelongsToSwipe = true;
+  } else {
+    // Now SwipeTracker has started consuming pan events, notify it to APZ so
+    // that APZ can discard queued events.
+    mAPZC->SetBrowserGestureResponse(aInputBlockId,
+                                     BrowserGestureResponse::Consumed);
+  }
+}
+
+nsBaseWidget::SwipeInfo nsBaseWidget::SendMayStartSwipe(
+    const mozilla::PanGestureInput& aSwipeStartEvent) {
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
+
+  uint32_t direction =
+      (aSwipeStartEvent.mPanDisplacement.x > 0.0)
+          ? (uint32_t)dom::SimpleGestureEvent_Binding::DIRECTION_RIGHT
+          : (uint32_t)dom::SimpleGestureEvent_Binding::DIRECTION_LEFT;
+
+  // We're ready to start the animation. Tell Gecko about it, and at the same
+  // time ask it if it really wants to start an animation for this event.
+  // This event also reports back the directions that we can swipe in.
+  LayoutDeviceIntPoint position = RoundedToInt(aSwipeStartEvent.mPanStartPoint *
+                                               ScreenToLayoutDeviceScale(1));
+  WidgetSimpleGestureEvent geckoEvent = SwipeTracker::CreateSwipeGestureEvent(
+      eSwipeGestureMayStart, this, position, aSwipeStartEvent.mTimeStamp);
+  geckoEvent.mDirection = direction;
+  geckoEvent.mDelta = 0.0;
+  geckoEvent.mAllowedDirections = 0;
+  bool shouldStartSwipe =
+      DispatchWindowEvent(geckoEvent);  // event cancelled == swipe should start
+
+  SwipeInfo result = {shouldStartSwipe, geckoEvent.mAllowedDirections};
+  return result;
+}
+
+WidgetWheelEvent nsBaseWidget::MayStartSwipeForAPZ(
+    const PanGestureInput& aPanInput, const APZEventResult& aApzResult) {
+  WidgetWheelEvent event = aPanInput.ToWidgetEvent(this);
+
+  // Ignore swipe-to-navigation in PiP window.
+  if (mIsPIPWindow) {
+    return event;
+  }
+
+  if (aPanInput.AllowsSwipe()) {
+    SwipeInfo swipeInfo = SendMayStartSwipe(aPanInput);
+    event.mCanTriggerSwipe = swipeInfo.wantsSwipe;
+    if (swipeInfo.wantsSwipe) {
+      if (aApzResult.GetStatus() == nsEventStatus_eIgnore) {
+        // APZ has determined and that scrolling horizontally in the
+        // requested direction is impossible, so it didn't do any
+        // scrolling for the event.
+        // We know now that MayStartSwipe wants a swipe, so we can start
+        // the swipe now.
+        TrackScrollEventAsSwipe(aPanInput, swipeInfo.allowedDirections,
+                                aApzResult.mInputBlockId);
+      } else if (!aApzResult.GetHandledResult() ||
+                 !aApzResult.GetHandledResult()->IsHandledByRoot()) {
+        // We don't know whether this event can start a swipe, so we need
+        // to queue up events and wait for a call to ReportSwipeStarted.
+        // APZ might already have started scrolling in response to the
+        // event if it knew that it's the right thing to do. In that case
+        // we'll still get a call to ReportSwipeStarted, and we will
+        // discard the queued events at that point.
+        mSwipeEventQueue = MakeUnique<SwipeEventQueue>(
+            swipeInfo.allowedDirections, aApzResult.mInputBlockId);
+      }
+    } else {
+      // Inform that the browser gesture didn't use the pan event (pan-start
+      // precisely), so that APZ can now start using the event for
+      // scrolling/overscrolling.
+      mAPZC->SetBrowserGestureResponse(aApzResult.mInputBlockId,
+                                       BrowserGestureResponse::NotConsumed);
+    }
+  }
+
+  if (mSwipeEventQueue &&
+      mSwipeEventQueue->inputBlockId == aApzResult.mInputBlockId) {
+    mSwipeEventQueue->queuedEvents.AppendElement(aPanInput);
+  }
+
+  return event;
+}
+
+bool nsBaseWidget::MayStartSwipeForNonAPZ(const PanGestureInput& aPanInput) {
+  // Ignore swipe-to-navigation in PiP window.
+  if (mIsPIPWindow) {
+    return false;
+  }
+
+  if (aPanInput.mType == PanGestureInput::PANGESTURE_MAYSTART ||
+      aPanInput.mType == PanGestureInput::PANGESTURE_START) {
+    mCurrentPanGestureBelongsToSwipe = false;
+  }
+  if (mCurrentPanGestureBelongsToSwipe) {
+    // Ignore this event. It's a momentum event from a scroll gesture
+    // that was processed as a swipe, and the swipe animation has
+    // already finished (so mSwipeTracker is already null).
+    MOZ_ASSERT(aPanInput.IsMomentum(),
+               "If the fingers are still on the touchpad, we should still have "
+               "a SwipeTracker, "
+               "and it should have consumed this event.");
+    return true;
+  }
+
+  if (!aPanInput.MayTriggerSwipe()) {
+    return false;
+  }
+
+  SwipeInfo swipeInfo = SendMayStartSwipe(aPanInput);
+
+  // We're in the non-APZ case here, but we still want to know whether
+  // the event was routed to a child process, so we use InputAPZContext
+  // to get that piece of information.
+  ScrollableLayerGuid guid;
+  uint64_t blockId = 0;
+  InputAPZContext context(guid, blockId, nsEventStatus_eIgnore);
+
+  WidgetWheelEvent event = aPanInput.ToWidgetEvent(this);
+  event.mCanTriggerSwipe = swipeInfo.wantsSwipe;
+  nsEventStatus status;
+  DispatchEvent(&event, status);
+  if (swipeInfo.wantsSwipe) {
+    if (context.WasRoutedToChildProcess()) {
+      // We don't know whether this event can start a swipe, so we need
+      // to queue up events and wait for a call to ReportSwipeStarted.
+      mSwipeEventQueue =
+          MakeUnique<SwipeEventQueue>(swipeInfo.allowedDirections, blockId);
+    } else if (event.TriggersSwipe()) {
+      TrackScrollEventAsSwipe(aPanInput, swipeInfo.allowedDirections, blockId);
+    }
+  }
+
+  if (mSwipeEventQueue && mSwipeEventQueue->inputBlockId == 0) {
+    mSwipeEventQueue->queuedEvents.AppendElement(aPanInput);
+  }
+
+  return true;
+}
+
+const IMENotificationRequests& nsIWidget::IMENotificationRequestsRef() {
+  TextEventDispatcher* dispatcher = GetTextEventDispatcher();
+  return dispatcher->IMENotificationRequestsRef();
+}
+
+void nsIWidget::PostHandleKeyEvent(mozilla::WidgetKeyboardEvent* aEvent) {}
+
+bool nsIWidget::GetEditCommands(NativeKeyBindingsType aType,
+                                const WidgetKeyboardEvent& aEvent,
+                                nsTArray<CommandInt>& aCommands) {
+  MOZ_ASSERT(aEvent.IsTrusted());
+  MOZ_ASSERT(aCommands.IsEmpty());
+  return true;
+}
+
+already_AddRefed<nsIBidiKeyboard> nsIWidget::CreateBidiKeyboard() {
+  if (XRE_IsContentProcess()) {
+    return CreateBidiKeyboardContentProcess();
+  }
+  return CreateBidiKeyboardInner();
+}
+
+#ifdef ANDROID
+already_AddRefed<nsIBidiKeyboard> nsIWidget::CreateBidiKeyboardInner() {
+  // no bidi keyboard implementation
+  return nullptr;
+}
+#endif
+
+namespace mozilla::widget {
+
+const char* ToChar(InputContext::Origin aOrigin) {
+  switch (aOrigin) {
+    case InputContext::ORIGIN_MAIN:
+      return "ORIGIN_MAIN";
+    case InputContext::ORIGIN_CONTENT:
+      return "ORIGIN_CONTENT";
+    default:
+      return "Unexpected value";
+  }
+}
+
+const char* ToChar(IMEMessage aIMEMessage) {
+  switch (aIMEMessage) {
+    case NOTIFY_IME_OF_NOTHING:
+      return "NOTIFY_IME_OF_NOTHING";
+    case NOTIFY_IME_OF_FOCUS:
+      return "NOTIFY_IME_OF_FOCUS";
+    case NOTIFY_IME_OF_BLUR:
+      return "NOTIFY_IME_OF_BLUR";
+    case NOTIFY_IME_OF_SELECTION_CHANGE:
+      return "NOTIFY_IME_OF_SELECTION_CHANGE";
+    case NOTIFY_IME_OF_TEXT_CHANGE:
+      return "NOTIFY_IME_OF_TEXT_CHANGE";
+    case NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED:
+      return "NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED";
+    case NOTIFY_IME_OF_POSITION_CHANGE:
+      return "NOTIFY_IME_OF_POSITION_CHANGE";
+    case NOTIFY_IME_OF_MOUSE_BUTTON_EVENT:
+      return "NOTIFY_IME_OF_MOUSE_BUTTON_EVENT";
+    case REQUEST_TO_COMMIT_COMPOSITION:
+      return "REQUEST_TO_COMMIT_COMPOSITION";
+    case REQUEST_TO_CANCEL_COMPOSITION:
+      return "REQUEST_TO_CANCEL_COMPOSITION";
+    default:
+      return "Unexpected value";
+  }
+}
+
+void NativeIMEContext::Init(nsIWidget* aWidget) {
+  if (!aWidget) {
+    mRawNativeIMEContext = reinterpret_cast<uintptr_t>(nullptr);
+    mOriginProcessID = static_cast<uint64_t>(-1);
+    return;
+  }
+  if (!XRE_IsContentProcess()) {
+    mRawNativeIMEContext = reinterpret_cast<uintptr_t>(
+        aWidget->GetNativeData(NS_RAW_NATIVE_IME_CONTEXT));
+    mOriginProcessID = 0;
+    return;
+  }
+  // If this is created in a child process, aWidget is an instance of
+  // PuppetWidget which doesn't support NS_RAW_NATIVE_IME_CONTEXT.
+  // Instead of that PuppetWidget::GetNativeIMEContext() returns cached
+  // native IME context of the parent process.
+  *this = aWidget->GetNativeIMEContext();
+}
+
+void NativeIMEContext::InitWithRawNativeIMEContext(void* aRawNativeIMEContext) {
+  if (NS_WARN_IF(!aRawNativeIMEContext)) {
+    mRawNativeIMEContext = reinterpret_cast<uintptr_t>(nullptr);
+    mOriginProcessID = static_cast<uint64_t>(-1);
+    return;
+  }
+  mRawNativeIMEContext = reinterpret_cast<uintptr_t>(aRawNativeIMEContext);
+  mOriginProcessID =
+      XRE_IsContentProcess() ? ContentChild::GetSingleton()->GetID() : 0;
+}
+
+void IMENotification::TextChangeDataBase::MergeWith(
+    const IMENotification::TextChangeDataBase& aOther) {
+  MOZ_ASSERT(aOther.IsValid(), "Merging data must store valid data");
+  MOZ_ASSERT(aOther.mStartOffset <= aOther.mRemovedEndOffset,
+             "end of removed text must be same or larger than start");
+  MOZ_ASSERT(aOther.mStartOffset <= aOther.mAddedEndOffset,
+             "end of added text must be same or larger than start");
+
+  if (!IsValid()) {
+    *this = aOther;
+    return;
+  }
+
+  // |mStartOffset| and |mRemovedEndOffset| represent all replaced or removed
+  // text ranges.  I.e., mStartOffset should be the smallest offset of all
+  // modified text ranges in old text.  |mRemovedEndOffset| should be the
+  // largest end offset in old text of all modified text ranges.
+  // |mAddedEndOffset| represents the end offset of all inserted text ranges.
+  // I.e., only this is an offset in new text.
+  // In other words, between mStartOffset and |mRemovedEndOffset| of the
+  // premodified text was already removed.  And some text whose length is
+  // |mAddedEndOffset - mStartOffset| is inserted to |mStartOffset|.  I.e.,
+  // this allows IME to mark dirty the modified text range with |mStartOffset|
+  // and |mRemovedEndOffset| if IME stores all text of the focused editor and
+  // to compute new text length with |mAddedEndOffset| and |mRemovedEndOffset|.
+  // Additionally, IME can retrieve only the text between |mStartOffset| and
+  // |mAddedEndOffset| for updating stored text.
+
+  // For comparing new and old |mStartOffset|/|mRemovedEndOffset| values, they
+  // should be adjusted to be in same text. The |newData.mStartOffset| and
+  // |newData.mRemovedEndOffset| should be computed as in old text because
+  // |mStartOffset| and |mRemovedEndOffset| represent the modified text range
+  // in the old text but even if some text before the values of the newData
+  // has already been modified, the values don't include the changes.
+
+  // For comparing new and old |mAddedEndOffset| values, they should be
+  // adjusted to be in same text.  The |oldData.mAddedEndOffset| should be
+  // computed as in the new text because |mAddedEndOffset| indicates the end
+  // offset of inserted text in the new text but |oldData.mAddedEndOffset|
+  // doesn't include any changes of the text before |newData.mAddedEndOffset|.
+
+  const TextChangeDataBase& newData = aOther;
+  const TextChangeDataBase oldData = *this;
+
+  // mCausedOnlyByComposition should be true only when all changes are caused
+  // by composition.
+  mCausedOnlyByComposition =
+      newData.mCausedOnlyByComposition && oldData.mCausedOnlyByComposition;
+
+  // mIncludingChangesWithoutComposition should be true if at least one of
+  // merged changes occurred without composition.
+  mIncludingChangesWithoutComposition =
+      newData.mIncludingChangesWithoutComposition ||
+      oldData.mIncludingChangesWithoutComposition;
+
+  // mIncludingChangesDuringComposition should be true when at least one of
+  // the merged non-composition changes occurred during the latest composition.
+  if (!newData.mCausedOnlyByComposition &&
+      !newData.mIncludingChangesDuringComposition) {
+    MOZ_ASSERT(newData.mIncludingChangesWithoutComposition);
+    MOZ_ASSERT(mIncludingChangesWithoutComposition);
+    // If new change is neither caused by composition nor occurred during
+    // composition, set mIncludingChangesDuringComposition to false because
+    // IME doesn't want outdated text changes as text change during current
+    // composition.
+    mIncludingChangesDuringComposition = false;
+  } else {
+    // Otherwise, set mIncludingChangesDuringComposition to true if either
+    // oldData or newData includes changes during composition.
+    mIncludingChangesDuringComposition =
+        newData.mIncludingChangesDuringComposition ||
+        oldData.mIncludingChangesDuringComposition;
+  }
+
+  if (newData.mStartOffset >= oldData.mAddedEndOffset) {
+    // Case 1:
+    // If new start is after old end offset of added text, it means that text
+    // after the modified range is modified.  Like:
+    // added range of old change:             +----------+
+    // removed range of new change:                           +----------+
+    // So, the old start offset is always the smaller offset.
+    mStartOffset = oldData.mStartOffset;
+    // The new end offset of removed text is moved by the old change and we
+    // need to cancel the move of the old change for comparing the offsets in
+    // same text because it doesn't make sensce to compare offsets in different
+    // text.
+    uint32_t newRemovedEndOffsetInOldText =
+        newData.mRemovedEndOffset - oldData.Difference();
+    mRemovedEndOffset =
+        std::max(newRemovedEndOffsetInOldText, oldData.mRemovedEndOffset);
+    // The new end offset of added text is always the larger offset.
+    mAddedEndOffset = newData.mAddedEndOffset;
+    return;
+  }
+
+  if (newData.mStartOffset >= oldData.mStartOffset) {
+    // If new start is in the modified range, it means that new data changes
+    // a part or all of the range.
+    mStartOffset = oldData.mStartOffset;
+    if (newData.mRemovedEndOffset >= oldData.mAddedEndOffset) {
+      // Case 2:
+      // If new end of removed text is greater than old end of added text, it
+      // means that all or a part of modified range modified again and text
+      // after the modified range is also modified.  Like:
+      // added range of old change:             +----------+
+      // removed range of new change:                   +----------+
+      // So, the new removed end offset is moved by the old change and we need
+      // to cancel the move of the old change for comparing the offsets in the
+      // same text because it doesn't make sense to compare the offsets in
+      // different text.
+      uint32_t newRemovedEndOffsetInOldText =
+          newData.mRemovedEndOffset - oldData.Difference();
+      mRemovedEndOffset =
+          std::max(newRemovedEndOffsetInOldText, oldData.mRemovedEndOffset);
+      // The old end of added text is replaced by new change. So, it should be
+      // same as the new start.  On the other hand, the new added end offset is
+      // always same or larger.  Therefore, the merged end offset of added
+      // text should be the new end offset of added text.
+      mAddedEndOffset = newData.mAddedEndOffset;
+      return;
+    }
+
+    // Case 3:
+    // If new end of removed text is less than old end of added text, it means
+    // that only a part of the modified range is modified again.  Like:
+    // added range of old change:             +------------+
+    // removed range of new change:               +-----+
+    // So, the new end offset of removed text should be same as the old end
+    // offset of removed text.  Therefore, the merged end offset of removed
+    // text should be the old text change's |mRemovedEndOffset|.
+    mRemovedEndOffset = oldData.mRemovedEndOffset;
+    // The old end of added text is moved by new change.  So, we need to cancel
+    // the move of the new change for comparing the offsets in same text.
+    uint32_t oldAddedEndOffsetInNewText =
+        oldData.mAddedEndOffset + newData.Difference();
+    mAddedEndOffset =
+        std::max(newData.mAddedEndOffset, oldAddedEndOffsetInNewText);
+    return;
+  }
+
+  if (newData.mRemovedEndOffset >= oldData.mStartOffset) {
+    // If new end of removed text is greater than old start (and new start is
+    // less than old start), it means that a part of modified range is modified
+    // again and some new text before the modified range is also modified.
+    MOZ_ASSERT(newData.mStartOffset < oldData.mStartOffset,
+               "new start offset should be less than old one here");
+    mStartOffset = newData.mStartOffset;
+    if (newData.mRemovedEndOffset >= oldData.mAddedEndOffset) {
+      // Case 4:
+      // If new end of removed text is greater than old end of added text, it
+      // means that all modified text and text after the modified range is
+      // modified.  Like:
+      // added range of old change:             +----------+
+      // removed range of new change:        +------------------+
+      // So, the new end of removed text is moved by the old change.  Therefore,
+      // we need to cancel the move of the old change for comparing the offsets
+      // in same text because it doesn't make sense to compare the offsets in
+      // different text.
+      uint32_t newRemovedEndOffsetInOldText =
+          newData.mRemovedEndOffset - oldData.Difference();
+      mRemovedEndOffset =
+          std::max(newRemovedEndOffsetInOldText, oldData.mRemovedEndOffset);
+      // The old end of added text is replaced by new change.  So, the old end
+      // offset of added text is same as new text change's start offset.  Then,
+      // new change's end offset of added text is always same or larger than
+      // it.  Therefore, merged end offset of added text is always the new end
+      // offset of added text.
+      mAddedEndOffset = newData.mAddedEndOffset;
+      return;
+    }
+
+    // Case 5:
+    // If new end of removed text is less than old end of added text, it
+    // means that only a part of the modified range is modified again.  Like:
+    // added range of old change:             +----------+
+    // removed range of new change:      +----------+
+    // So, the new end of removed text should be same as old end of removed
+    // text for preventing end of removed text to be modified.  Therefore,
+    // merged end offset of removed text is always the old end offset of removed
+    // text.
+    mRemovedEndOffset = oldData.mRemovedEndOffset;
+    // The old end of added text is moved by this change.  So, we need to
+    // cancel the move of the new change for comparing the offsets in same text
+    // because it doesn't make sense to compare the offsets in different text.
+    uint32_t oldAddedEndOffsetInNewText =
+        oldData.mAddedEndOffset + newData.Difference();
+    mAddedEndOffset =
+        std::max(newData.mAddedEndOffset, oldAddedEndOffsetInNewText);
+    return;
+  }
+
+  // Case 6:
+  // Otherwise, i.e., both new end of added text and new start are less than
+  // old start, text before the modified range is modified.  Like:
+  // added range of old change:                  +----------+
+  // removed range of new change: +----------+
+  MOZ_ASSERT(newData.mStartOffset < oldData.mStartOffset,
+             "new start offset should be less than old one here");
+  mStartOffset = newData.mStartOffset;
+  MOZ_ASSERT(newData.mRemovedEndOffset < oldData.mRemovedEndOffset,
+             "new removed end offset should be less than old one here");
+  mRemovedEndOffset = oldData.mRemovedEndOffset;
+  // The end of added text should be adjusted with the new difference.
+  uint32_t oldAddedEndOffsetInNewText =
+      oldData.mAddedEndOffset + newData.Difference();
+  mAddedEndOffset =
+      std::max(newData.mAddedEndOffset, oldAddedEndOffsetInNewText);
+}
+
+#ifdef DEBUG
+
+// Let's test the code of merging multiple text change data in debug build
+// and crash if one of them fails because this feature is very complex but
+// cannot be tested with mochitest.
+void IMENotification::TextChangeDataBase::Test() {
+  static bool gTestTextChangeEvent = true;
+  if (!gTestTextChangeEvent) {
+    return;
+  }
+  gTestTextChangeEvent = false;
+
+  /****************************************************************************
+   * Case 1
+   ****************************************************************************/
+
+  // Appending text
+  MergeWith(TextChangeData(10, 10, 20, false, false));
+  MergeWith(TextChangeData(20, 20, 35, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+             "Test 1-1-1: mStartOffset should be the first offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 10,  // 20 - (20 - 10)
+      "Test 1-1-2: mRemovedEndOffset should be the first end of removed text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 35,
+      "Test 1-1-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Removing text (longer line -> shorter line)
+  MergeWith(TextChangeData(10, 20, 10, false, false));
+  MergeWith(TextChangeData(10, 30, 10, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+             "Test 1-2-1: mStartOffset should be the first offset");
+  MOZ_ASSERT(mRemovedEndOffset == 40,  // 30 + (10 - 20)
+             "Test 1-2-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "with already removed length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 10,
+      "Test 1-2-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Removing text (shorter line -> longer line)
+  MergeWith(TextChangeData(10, 20, 10, false, false));
+  MergeWith(TextChangeData(10, 15, 10, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+             "Test 1-3-1: mStartOffset should be the first offset");
+  MOZ_ASSERT(mRemovedEndOffset == 25,  // 15 + (10 - 20)
+             "Test 1-3-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "with already removed length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 10,
+      "Test 1-3-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Appending text at different point (not sure if actually occurs)
+  MergeWith(TextChangeData(10, 10, 20, false, false));
+  MergeWith(TextChangeData(55, 55, 60, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+             "Test 1-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 45,  // 55 - (10 - 20)
+      "Test 1-4-2: mRemovedEndOffset should be the the largest end of removed "
+      "text without already added length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 60,
+      "Test 1-4-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Removing text at different point (not sure if actually occurs)
+  MergeWith(TextChangeData(10, 20, 10, false, false));
+  MergeWith(TextChangeData(55, 68, 55, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+             "Test 1-5-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 78,  // 68 - (10 - 20)
+      "Test 1-5-2: mRemovedEndOffset should be the the largest end of removed "
+      "text with already removed length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 55,
+      "Test 1-5-3: mAddedEndOffset should be the largest end of added text");
+  Clear();
+
+  // Replacing text and append text (becomes longer)
+  MergeWith(TextChangeData(30, 35, 32, false, false));
+  MergeWith(TextChangeData(32, 32, 40, false, false));
+  MOZ_ASSERT(mStartOffset == 30,
+             "Test 1-6-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 35,  // 32 - (32 - 35)
+      "Test 1-6-2: mRemovedEndOffset should be the the first end of removed "
+      "text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 40,
+      "Test 1-6-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text and append text (becomes shorter)
+  MergeWith(TextChangeData(30, 35, 32, false, false));
+  MergeWith(TextChangeData(32, 32, 33, false, false));
+  MOZ_ASSERT(mStartOffset == 30,
+             "Test 1-7-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 35,  // 32 - (32 - 35)
+      "Test 1-7-2: mRemovedEndOffset should be the the first end of removed "
+      "text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 33,
+      "Test 1-7-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Removing text and replacing text after first range (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(30, 35, 30, false, false));
+  MergeWith(TextChangeData(32, 34, 48, false, false));
+  MOZ_ASSERT(mStartOffset == 30,
+             "Test 1-8-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 39,  // 34 - (30 - 35)
+             "Test 1-8-2: mRemovedEndOffset should be the the first end of "
+             "removed text "
+             "without already removed text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 48,
+      "Test 1-8-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Removing text and replacing text after first range (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(30, 35, 30, false, false));
+  MergeWith(TextChangeData(32, 38, 36, false, false));
+  MOZ_ASSERT(mStartOffset == 30,
+             "Test 1-9-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 43,  // 38 - (30 - 35)
+             "Test 1-9-2: mRemovedEndOffset should be the the first end of "
+             "removed text "
+             "without already removed text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 36,
+      "Test 1-9-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  /****************************************************************************
+   * Case 2
+   ****************************************************************************/
+
+  // Replacing text in around end of added text (becomes shorter) (not sure
+  // if actually occurs)
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(53, 60, 54, false, false));
+  MOZ_ASSERT(mStartOffset == 50,
+             "Test 2-1-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 55,  // 60 - (55 - 50)
+             "Test 2-1-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "without already added text length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 54,
+      "Test 2-1-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text around end of added text (becomes longer) (not sure
+  // if actually occurs)
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(54, 62, 68, false, false));
+  MOZ_ASSERT(mStartOffset == 50,
+             "Test 2-2-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 57,  // 62 - (55 - 50)
+             "Test 2-2-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "without already added text length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 68,
+      "Test 2-2-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text around end of replaced text (became shorter) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(36, 48, 45, false, false));
+  MergeWith(TextChangeData(43, 50, 49, false, false));
+  MOZ_ASSERT(mStartOffset == 36,
+             "Test 2-3-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 53,  // 50 - (45 - 48)
+             "Test 2-3-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "without already removed text length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 49,
+      "Test 2-3-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text around end of replaced text (became longer) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(36, 52, 53, false, false));
+  MergeWith(TextChangeData(43, 68, 61, false, false));
+  MOZ_ASSERT(mStartOffset == 36,
+             "Test 2-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 67,  // 68 - (53 - 52)
+             "Test 2-4-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "without already added text length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 61,
+      "Test 2-4-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  /****************************************************************************
+   * Case 3
+   ****************************************************************************/
+
+  // Appending text in already added text (not sure if actually occurs)
+  MergeWith(TextChangeData(10, 10, 20, false, false));
+  MergeWith(TextChangeData(15, 15, 30, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+             "Test 3-1-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 10,
+             "Test 3-1-2: mRemovedEndOffset should be the the first end of "
+             "removed text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 35,  // 20 + (30 - 15)
+      "Test 3-1-3: mAddedEndOffset should be the first end of added text with "
+      "added text length by the new change");
+  Clear();
+
+  // Replacing text in added text (not sure if actually occurs)
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(52, 53, 56, false, false));
+  MOZ_ASSERT(mStartOffset == 50,
+             "Test 3-2-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 50,
+             "Test 3-2-2: mRemovedEndOffset should be the the first end of "
+             "removed text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 58,  // 55 + (56 - 53)
+      "Test 3-2-3: mAddedEndOffset should be the first end of added text with "
+      "added text length by the new change");
+  Clear();
+
+  // Replacing text in replaced text (became shorter) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(36, 48, 45, false, false));
+  MergeWith(TextChangeData(37, 38, 50, false, false));
+  MOZ_ASSERT(mStartOffset == 36,
+             "Test 3-3-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 48,
+             "Test 3-3-2: mRemovedEndOffset should be the the first end of "
+             "removed text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 57,  // 45 + (50 - 38)
+      "Test 3-3-3: mAddedEndOffset should be the first end of added text with "
+      "added text length by the new change");
+  Clear();
+
+  // Replacing text in replaced text (became longer) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(32, 48, 53, false, false));
+  MergeWith(TextChangeData(43, 50, 52, false, false));
+  MOZ_ASSERT(mStartOffset == 32,
+             "Test 3-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 48,
+             "Test 3-4-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "without already added text length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 55,  // 53 + (52 - 50)
+      "Test 3-4-3: mAddedEndOffset should be the first end of added text with "
+      "added text length by the new change");
+  Clear();
+
+  // Replacing text in replaced text (became shorter) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(36, 48, 50, false, false));
+  MergeWith(TextChangeData(37, 49, 47, false, false));
+  MOZ_ASSERT(mStartOffset == 36,
+             "Test 3-5-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 48,
+      "Test 3-5-2: mRemovedEndOffset should be the the first end of removed "
+      "text");
+  MOZ_ASSERT(mAddedEndOffset == 48,  // 50 + (47 - 49)
+             "Test 3-5-3: mAddedEndOffset should be the first end of added "
+             "text without "
+             "removed text length by the new change");
+  Clear();
+
+  // Replacing text in replaced text (became longer) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(32, 48, 53, false, false));
+  MergeWith(TextChangeData(43, 50, 47, false, false));
+  MOZ_ASSERT(mStartOffset == 32,
+             "Test 3-6-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 48,
+             "Test 3-6-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "without already added text length");
+  MOZ_ASSERT(mAddedEndOffset == 50,  // 53 + (47 - 50)
+             "Test 3-6-3: mAddedEndOffset should be the first end of added "
+             "text without "
+             "removed text length by the new change");
+  Clear();
+
+  /****************************************************************************
+   * Case 4
+   ****************************************************************************/
+
+  // Replacing text all of already append text (not sure if actually occurs)
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(44, 66, 68, false, false));
+  MOZ_ASSERT(mStartOffset == 44,
+             "Test 4-1-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 61,  // 66 - (55 - 50)
+             "Test 4-1-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "without already added text length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 68,
+      "Test 4-1-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text around a point in which text was removed (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(50, 62, 50, false, false));
+  MergeWith(TextChangeData(44, 66, 68, false, false));
+  MOZ_ASSERT(mStartOffset == 44,
+             "Test 4-2-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 78,  // 66 - (50 - 62)
+             "Test 4-2-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "without already removed text length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 68,
+      "Test 4-2-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text all replaced text (became shorter) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(50, 62, 60, false, false));
+  MergeWith(TextChangeData(49, 128, 130, false, false));
+  MOZ_ASSERT(mStartOffset == 49,
+             "Test 4-3-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 130,  // 128 - (60 - 62)
+             "Test 4-3-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "without already removed text length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 130,
+      "Test 4-3-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text all replaced text (became longer) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(50, 61, 73, false, false));
+  MergeWith(TextChangeData(44, 100, 50, false, false));
+  MOZ_ASSERT(mStartOffset == 44,
+             "Test 4-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 88,  // 100 - (73 - 61)
+             "Test 4-4-2: mRemovedEndOffset should be the the last end of "
+             "removed text "
+             "with already added text length");
+  MOZ_ASSERT(
+      mAddedEndOffset == 50,
+      "Test 4-4-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  /****************************************************************************
+   * Case 5
+   ****************************************************************************/
+
+  // Replacing text around start of added text (not sure if actually occurs)
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(48, 52, 49, false, false));
+  MOZ_ASSERT(mStartOffset == 48,
+             "Test 5-1-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 50,
+      "Test 5-1-2: mRemovedEndOffset should be the the first end of removed "
+      "text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 52,  // 55 + (52 - 49)
+      "Test 5-1-3: mAddedEndOffset should be the first end of added text with "
+      "added text length by the new change");
+  Clear();
+
+  // Replacing text around start of replaced text (became shorter) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(50, 60, 58, false, false));
+  MergeWith(TextChangeData(43, 50, 48, false, false));
+  MOZ_ASSERT(mStartOffset == 43,
+             "Test 5-2-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 60,
+      "Test 5-2-2: mRemovedEndOffset should be the the first end of removed "
+      "text");
+  MOZ_ASSERT(mAddedEndOffset == 56,  // 58 + (48 - 50)
+             "Test 5-2-3: mAddedEndOffset should be the first end of added "
+             "text without "
+             "removed text length by the new change");
+  Clear();
+
+  // Replacing text around start of replaced text (became longer) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(50, 60, 68, false, false));
+  MergeWith(TextChangeData(43, 55, 53, false, false));
+  MOZ_ASSERT(mStartOffset == 43,
+             "Test 5-3-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 60,
+      "Test 5-3-2: mRemovedEndOffset should be the the first end of removed "
+      "text");
+  MOZ_ASSERT(mAddedEndOffset == 66,  // 68 + (53 - 55)
+             "Test 5-3-3: mAddedEndOffset should be the first end of added "
+             "text without "
+             "removed text length by the new change");
+  Clear();
+
+  // Replacing text around start of replaced text (became shorter) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(50, 60, 58, false, false));
+  MergeWith(TextChangeData(43, 50, 128, false, false));
+  MOZ_ASSERT(mStartOffset == 43,
+             "Test 5-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 60,
+      "Test 5-4-2: mRemovedEndOffset should be the the first end of removed "
+      "text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 136,  // 58 + (128 - 50)
+      "Test 5-4-3: mAddedEndOffset should be the first end of added text with "
+      "added text length by the new change");
+  Clear();
+
+  // Replacing text around start of replaced text (became longer) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(50, 60, 68, false, false));
+  MergeWith(TextChangeData(43, 55, 65, false, false));
+  MOZ_ASSERT(mStartOffset == 43,
+             "Test 5-5-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 60,
+      "Test 5-5-2: mRemovedEndOffset should be the the first end of removed "
+      "text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 78,  // 68 + (65 - 55)
+      "Test 5-5-3: mAddedEndOffset should be the first end of added text with "
+      "added text length by the new change");
+  Clear();
+
+  /****************************************************************************
+   * Case 6
+   ****************************************************************************/
+
+  // Appending text before already added text (not sure if actually occurs)
+  MergeWith(TextChangeData(30, 30, 45, false, false));
+  MergeWith(TextChangeData(10, 10, 20, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+             "Test 6-1-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 30,
+      "Test 6-1-2: mRemovedEndOffset should be the the largest end of removed "
+      "text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 55,  // 45 + (20 - 10)
+      "Test 6-1-3: mAddedEndOffset should be the first end of added text with "
+      "added text length by the new change");
+  Clear();
+
+  // Removing text before already removed text (not sure if actually occurs)
+  MergeWith(TextChangeData(30, 35, 30, false, false));
+  MergeWith(TextChangeData(10, 25, 10, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+             "Test 6-2-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 35,
+      "Test 6-2-2: mRemovedEndOffset should be the the largest end of removed "
+      "text");
+  MOZ_ASSERT(
+      mAddedEndOffset == 15,  // 30 - (25 - 10)
+      "Test 6-2-3: mAddedEndOffset should be the first end of added text with "
+      "removed text length by the new change");
+  Clear();
+
+  // Replacing text before already replaced text (not sure if actually occurs)
+  MergeWith(TextChangeData(50, 65, 70, false, false));
+  MergeWith(TextChangeData(13, 24, 15, false, false));
+  MOZ_ASSERT(mStartOffset == 13,
+             "Test 6-3-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 65,
+      "Test 6-3-2: mRemovedEndOffset should be the the largest end of removed "
+      "text");
+  MOZ_ASSERT(mAddedEndOffset == 61,  // 70 + (15 - 24)
+             "Test 6-3-3: mAddedEndOffset should be the first end of added "
+             "text without "
+             "removed text length by the new change");
+  Clear();
+
+  // Replacing text before already replaced text (not sure if actually occurs)
+  MergeWith(TextChangeData(50, 65, 70, false, false));
+  MergeWith(TextChangeData(13, 24, 36, false, false));
+  MOZ_ASSERT(mStartOffset == 13,
+             "Test 6-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(
+      mRemovedEndOffset == 65,
+      "Test 6-4-2: mRemovedEndOffset should be the the largest end of removed "
+      "text");
+  MOZ_ASSERT(mAddedEndOffset == 82,  // 70 + (36 - 24)
+             "Test 6-4-3: mAddedEndOffset should be the first end of added "
+             "text without "
+             "removed text length by the new change");
+  Clear();
+}
+
+#endif  // #ifdef DEBUG
+
+}  // namespace mozilla::widget
+
+#ifdef DEBUG
+//////////////////////////////////////////////////////////////
+//
+// Convert a GUI event message code to a string.
+// Makes it a lot easier to debug events.
+//
+// See gtk/nsWidget.cpp and windows/nsWindow.cpp
+// for a DebugPrintEvent() function that uses
+// this.
+//
+//////////////////////////////////////////////////////////////
+/* static */
+nsAutoString nsBaseWidget::debug_GuiEventToString(WidgetGUIEvent* aGuiEvent) {
+  NS_ASSERTION(nullptr != aGuiEvent, "cmon, null gui event.");
+
+  nsAutoString eventName(u"UNKNOWN"_ns);
+
+#  define _ASSIGN_eventName(_value, _name) \
+    case _value:                           \
+      eventName.AssignLiteral(_name);      \
+      break
+
+  switch (aGuiEvent->mMessage) {
+    _ASSIGN_eventName(eBlur, "eBlur");
+    _ASSIGN_eventName(eDrop, "eDrop");
+    _ASSIGN_eventName(eDragEnter, "eDragEnter");
+    _ASSIGN_eventName(eDragExit, "eDragExit");
+    _ASSIGN_eventName(eDragOver, "eDragOver");
+    _ASSIGN_eventName(eEditorInput, "eEditorInput");
+    _ASSIGN_eventName(eFocus, "eFocus");
+    _ASSIGN_eventName(eFocusIn, "eFocusIn");
+    _ASSIGN_eventName(eFocusOut, "eFocusOut");
+    _ASSIGN_eventName(eFormSelect, "eFormSelect");
+    _ASSIGN_eventName(eFormChange, "eFormChange");
+    _ASSIGN_eventName(eFormReset, "eFormReset");
+    _ASSIGN_eventName(eFormSubmit, "eFormSubmit");
+    _ASSIGN_eventName(eImageAbort, "eImageAbort");
+    _ASSIGN_eventName(eLoadError, "eLoadError");
+    _ASSIGN_eventName(eKeyDown, "eKeyDown");
+    _ASSIGN_eventName(eKeyPress, "eKeyPress");
+    _ASSIGN_eventName(eKeyUp, "eKeyUp");
+    _ASSIGN_eventName(eMouseEnterIntoWidget, "eMouseEnterIntoWidget");
+    _ASSIGN_eventName(eMouseExitFromWidget, "eMouseExitFromWidget");
+    _ASSIGN_eventName(eMouseDown, "eMouseDown");
+    _ASSIGN_eventName(eMouseUp, "eMouseUp");
+    _ASSIGN_eventName(eMouseClick, "eMouseClick");
+    _ASSIGN_eventName(eMouseAuxClick, "eMouseAuxClick");
+    _ASSIGN_eventName(eMouseDoubleClick, "eMouseDoubleClick");
+    _ASSIGN_eventName(eMouseMove, "eMouseMove");
+    _ASSIGN_eventName(eLoad, "eLoad");
+    _ASSIGN_eventName(ePopState, "ePopState");
+    _ASSIGN_eventName(eBeforeScriptExecute, "eBeforeScriptExecute");
+    _ASSIGN_eventName(eAfterScriptExecute, "eAfterScriptExecute");
+    _ASSIGN_eventName(eUnload, "eUnload");
+    _ASSIGN_eventName(eHashChange, "eHashChange");
+    _ASSIGN_eventName(eReadyStateChange, "eReadyStateChange");
+    _ASSIGN_eventName(eXULBroadcast, "eXULBroadcast");
+    _ASSIGN_eventName(eXULCommandUpdate, "eXULCommandUpdate");
+
+#  undef _ASSIGN_eventName
+
+    default: {
+      eventName.AssignLiteral("UNKNOWN: ");
+      eventName.AppendInt(aGuiEvent->mMessage);
+    } break;
+  }
+
+  return nsAutoString(eventName);
+}
+//////////////////////////////////////////////////////////////
+//
+// Code to deal with paint and event debug prefs.
+//
+//////////////////////////////////////////////////////////////
+struct PrefPair {
+  const char* name;
+  bool value;
+};
+
+static PrefPair debug_PrefValues[] = {
+    {"nglayout.debug.crossing_event_dumping", false},
+    {"nglayout.debug.event_dumping", false},
+    {"nglayout.debug.invalidate_dumping", false},
+    {"nglayout.debug.motion_event_dumping", false},
+    {"nglayout.debug.paint_dumping", false}};
+
+//////////////////////////////////////////////////////////////
+bool nsBaseWidget::debug_GetCachedBoolPref(const char* aPrefName) {
+  NS_ASSERTION(nullptr != aPrefName, "cmon, pref name is null.");
+
+  for (uint32_t i = 0; i < ArrayLength(debug_PrefValues); i++) {
+    if (strcmp(debug_PrefValues[i].name, aPrefName) == 0) {
+      return debug_PrefValues[i].value;
+    }
+  }
+
+  return false;
+}
+//////////////////////////////////////////////////////////////
+static void debug_SetCachedBoolPref(const char* aPrefName, bool aValue) {
+  NS_ASSERTION(nullptr != aPrefName, "cmon, pref name is null.");
+
+  for (uint32_t i = 0; i < ArrayLength(debug_PrefValues); i++) {
+    if (strcmp(debug_PrefValues[i].name, aPrefName) == 0) {
+      debug_PrefValues[i].value = aValue;
+
+      return;
+    }
+  }
+
+  NS_ASSERTION(false, "cmon, this code is not reached dude.");
+}
+
+//////////////////////////////////////////////////////////////
+class Debug_PrefObserver final : public nsIObserver {
+  ~Debug_PrefObserver() = default;
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+};
+
+NS_IMPL_ISUPPORTS(Debug_PrefObserver, nsIObserver)
+
+NS_IMETHODIMP
+Debug_PrefObserver::Observe(nsISupports* subject, const char* topic,
+                            const char16_t* data) {
+  NS_ConvertUTF16toUTF8 prefName(data);
+
+  bool value = Preferences::GetBool(prefName.get(), false);
+  debug_SetCachedBoolPref(prefName.get(), value);
+  return NS_OK;
+}
+
+//////////////////////////////////////////////////////////////
+/* static */ void debug_RegisterPrefCallbacks() {
+  static bool once = true;
+
+  if (!once) {
+    return;
+  }
+
+  once = false;
+
+  nsCOMPtr<nsIObserver> obs(new Debug_PrefObserver());
+  for (uint32_t i = 0; i < ArrayLength(debug_PrefValues); i++) {
+    // Initialize the pref values
+    debug_PrefValues[i].value =
+        Preferences::GetBool(debug_PrefValues[i].name, false);
+
+    if (obs) {
+      // Register callbacks for when these change
+      nsCString name;
+      name.AssignLiteral(debug_PrefValues[i].name,
+                         strlen(debug_PrefValues[i].name));
+      Preferences::AddStrongObserver(obs, name);
+    }
+  }
+}
+//////////////////////////////////////////////////////////////
+static int32_t _GetPrintCount() {
+  static int32_t sCount = 0;
+
+  return ++sCount;
+}
+//////////////////////////////////////////////////////////////
+/* static */
+void nsBaseWidget::debug_DumpEvent(FILE* aFileOut, nsIWidget* aWidget,
+                                   WidgetGUIEvent* aGuiEvent,
+                                   const char* aWidgetName, int32_t aWindowID) {
+  if (aGuiEvent->mMessage == eMouseMove) {
+    if (!debug_GetCachedBoolPref("nglayout.debug.motion_event_dumping")) return;
+  }
+
+  if (aGuiEvent->mMessage == eMouseEnterIntoWidget ||
+      aGuiEvent->mMessage == eMouseExitFromWidget) {
+    if (!debug_GetCachedBoolPref("nglayout.debug.crossing_event_dumping"))
+      return;
+  }
+
+  if (!debug_GetCachedBoolPref("nglayout.debug.event_dumping")) return;
+
+  NS_LossyConvertUTF16toASCII tempString(
+      debug_GuiEventToString(aGuiEvent).get());
+
+  fprintf(aFileOut, "%4d %-26s widget=%-8p name=%-12s id=0x%-6x refpt=%d,%d\n",
+          _GetPrintCount(), tempString.get(), (void*)aWidget, aWidgetName,
+          aWindowID, aGuiEvent->mRefPoint.x.value,
+          aGuiEvent->mRefPoint.y.value);
+}
+//////////////////////////////////////////////////////////////
+/* static */
+void nsBaseWidget::debug_DumpPaintEvent(FILE* aFileOut, nsIWidget* aWidget,
+                                        const nsIntRegion& aRegion,
+                                        const char* aWidgetName,
+                                        int32_t aWindowID) {
+  NS_ASSERTION(nullptr != aFileOut, "cmon, null output FILE");
+  NS_ASSERTION(nullptr != aWidget, "cmon, the widget is null");
+
+  if (!debug_GetCachedBoolPref("nglayout.debug.paint_dumping")) return;
+
+  nsIntRect rect = aRegion.GetBounds();
+  fprintf(aFileOut,
+          "%4d PAINT      widget=%p name=%-12s id=0x%-6x bounds-rect=%3d,%-3d "
+          "%3d,%-3d",
+          _GetPrintCount(), (void*)aWidget, aWidgetName, aWindowID, rect.X(),
+          rect.Y(), rect.Width(), rect.Height());
+
+  fprintf(aFileOut, "\n");
+}
+//////////////////////////////////////////////////////////////
+/* static */
+void nsBaseWidget::debug_DumpInvalidate(FILE* aFileOut, nsIWidget* aWidget,
+                                        const LayoutDeviceIntRect* aRect,
+                                        const char* aWidgetName,
+                                        int32_t aWindowID) {
+  if (!debug_GetCachedBoolPref("nglayout.debug.invalidate_dumping")) return;
+
+  NS_ASSERTION(nullptr != aFileOut, "cmon, null output FILE");
+  NS_ASSERTION(nullptr != aWidget, "cmon, the widget is null");
+
+  fprintf(aFileOut, "%4d Invalidate widget=%p name=%-12s id=0x%-6x",
+          _GetPrintCount(), (void*)aWidget, aWidgetName, aWindowID);
+
+  if (aRect) {
+    fprintf(aFileOut, " rect=%3d,%-3d %3d,%-3d", aRect->X(), aRect->Y(),
+            aRect->Width(), aRect->Height());
+  } else {
+    fprintf(aFileOut, " rect=%-15s", "none");
+  }
+
+  fprintf(aFileOut, "\n");
+}
+//////////////////////////////////////////////////////////////
+
+#endif  // DEBUG
diff --git a/widget/nsBaseWidget.h b/widget/nsBaseWidget.h
new file mode 100644
index 0000000000..8b6e8ad0eb
--- /dev/null
+++ b/widget/nsBaseWidget.h
@@ -0,0 +1,777 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef nsBaseWidget_h__
+#define nsBaseWidget_h__
+
+#include "InputData.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/WidgetUtils.h"
+#include "mozilla/dom/MouseEventBinding.h"
+#include "mozilla/layers/APZCCallbackHelper.h"
+#include "mozilla/layers/CompositorOptions.h"
+#include "mozilla/layers/NativeLayer.h"
+#include "mozilla/widget/ThemeChangeKind.h"
+#include "mozilla/widget/WindowOcclusionState.h"
+#include "nsRect.h"
+#include "nsIWidget.h"
+#include "nsWidgetsCID.h"
+#include "nsIFile.h"
+#include "nsString.h"
+#include "nsCOMPtr.h"
+#include "nsIRollupListener.h"
+#include "nsIObserver.h"
+#include "nsIWidgetListener.h"
+#include "nsPIDOMWindow.h"
+#include "nsWeakReference.h"
+
+#include <algorithm>
+
+class nsIContent;
+class gfxContext;
+
+namespace mozilla {
+class CompositorVsyncDispatcher;
+class LiveResizeListener;
+class FallbackRenderer;
+class SwipeTracker;
+struct SwipeEventQueue;
+class WidgetWheelEvent;
+
+#ifdef ACCESSIBILITY
+namespace a11y {
+class LocalAccessible;
+}
+#endif
+
+namespace gfx {
+class DrawTarget;
+class SourceSurface;
+}  // namespace gfx
+
+namespace layers {
+class CompositorBridgeChild;
+class CompositorBridgeParent;
+class IAPZCTreeManager;
+class GeckoContentController;
+class APZEventState;
+struct APZEventResult;
+class CompositorSession;
+class ImageContainer;
+class WebRenderLayerManager;
+struct ScrollableLayerGuid;
+class RemoteCompositorSession;
+}  // namespace layers
+
+namespace widget {
+class CompositorWidgetDelegate;
+class InProcessCompositorWidget;
+class WidgetRenderingContext;
+}  // namespace widget
+
+class CompositorVsyncDispatcher;
+}  // namespace mozilla
+
+namespace base {
+class Thread;
+}  // namespace base
+
+// Windows specific constant indicating the maximum number of touch points the
+// inject api will allow. This also sets the maximum numerical value for touch
+// ids we can use when injecting touch points on Windows.
+#define TOUCH_INJECT_MAX_POINTS 256
+
+class nsBaseWidget;
+
+// Helper class used in shutting down gfx related code.
+class WidgetShutdownObserver final : public nsIObserver {
+  ~WidgetShutdownObserver();
+
+ public:
+  explicit WidgetShutdownObserver(nsBaseWidget* aWidget);
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  void Register();
+  void Unregister();
+
+  nsBaseWidget* mWidget;
+  bool mRegistered;
+};
+
+// Helper class used for observing locales change.
+class LocalesChangedObserver final : public nsIObserver {
+  ~LocalesChangedObserver();
+
+ public:
+  explicit LocalesChangedObserver(nsBaseWidget* aWidget);
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  void Register();
+  void Unregister();
+
+  nsBaseWidget* mWidget;
+  bool mRegistered;
+};
+
+/**
+ * Common widget implementation used as base class for native
+ * or crossplatform implementations of Widgets.
+ * All cross-platform behavior that all widgets need to implement
+ * should be placed in this class.
+ * (Note: widget implementations are not required to use this
+ * class, but it gives them a head start.)
+ */
+
+class nsBaseWidget : public nsIWidget, public nsSupportsWeakReference {
+  template <class EventType, class InputType>
+  friend class DispatchEventOnMainThread;
+  friend class mozilla::widget::InProcessCompositorWidget;
+  friend class mozilla::layers::RemoteCompositorSession;
+
+ protected:
+  typedef base::Thread Thread;
+  typedef mozilla::gfx::DrawTarget DrawTarget;
+  typedef mozilla::gfx::SourceSurface SourceSurface;
+  typedef mozilla::layers::BufferMode BufferMode;
+  typedef mozilla::layers::CompositorBridgeChild CompositorBridgeChild;
+  typedef mozilla::layers::CompositorBridgeParent CompositorBridgeParent;
+  typedef mozilla::layers::IAPZCTreeManager IAPZCTreeManager;
+  typedef mozilla::layers::GeckoContentController GeckoContentController;
+  typedef mozilla::layers::ScrollableLayerGuid ScrollableLayerGuid;
+  typedef mozilla::layers::APZEventState APZEventState;
+  typedef mozilla::CSSIntRect CSSIntRect;
+  typedef mozilla::CSSRect CSSRect;
+  typedef mozilla::ScreenRotation ScreenRotation;
+  typedef mozilla::widget::CompositorWidgetDelegate CompositorWidgetDelegate;
+  typedef mozilla::layers::CompositorSession CompositorSession;
+  typedef mozilla::layers::ImageContainer ImageContainer;
+
+  virtual ~nsBaseWidget();
+
+ public:
+  nsBaseWidget();
+
+  explicit nsBaseWidget(BorderStyle aBorderStyle);
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+
+  // nsIWidget interface
+  void CaptureRollupEvents(bool aDoCapture) override {}
+  nsIWidgetListener* GetWidgetListener() const override;
+  void SetWidgetListener(nsIWidgetListener* alistener) override;
+  void Destroy() override;
+  void SetParent(nsIWidget* aNewParent) override{};
+  nsIWidget* GetParent() override;
+  nsIWidget* GetTopLevelWidget() override;
+  nsIWidget* GetSheetWindowParent(void) override;
+  float GetDPI() override;
+  void AddChild(nsIWidget* aChild) override;
+  void RemoveChild(nsIWidget* aChild) override;
+
+  void SetZIndex(int32_t aZIndex) override;
+  void PlaceBehind(nsTopLevelWidgetZPlacement aPlacement, nsIWidget* aWidget,
+                   bool aActivate) override {}
+
+  void GetWorkspaceID(nsAString& workspaceID) override;
+  void MoveToWorkspace(const nsAString& workspaceID) override;
+  bool IsTiled() const override { return mIsTiled; }
+
+  bool IsFullyOccluded() const override { return mIsFullyOccluded; }
+
+  void SetCursor(const Cursor&) override;
+  void SetCustomCursorAllowed(bool) override;
+  void ClearCachedCursor() final {
+    mCursor = {};
+    mUpdateCursor = true;
+  }
+  void SetTransparencyMode(TransparencyMode aMode) override;
+  TransparencyMode GetTransparencyMode() override;
+  void SetWindowShadowStyle(mozilla::WindowShadow) override {}
+  void SetShowsToolbarButton(bool aShow) override {}
+  void SetSupportsNativeFullscreen(bool aSupportsNativeFullscreen) override {}
+  void SetWindowAnimationType(WindowAnimationType aType) override {}
+  void HideWindowChrome(bool aShouldHide) override {}
+  bool PrepareForFullscreenTransition(nsISupports** aData) override {
+    return false;
+  }
+  void PerformFullscreenTransition(FullscreenTransitionStage aStage,
+                                   uint16_t aDuration, nsISupports* aData,
+                                   nsIRunnable* aCallback) override;
+  void CleanupFullscreenTransition() override {}
+  already_AddRefed<Screen> GetWidgetScreen() override;
+  nsresult MakeFullScreen(bool aFullScreen) override;
+  void InfallibleMakeFullScreen(bool aFullScreen);
+
+  WindowRenderer* GetWindowRenderer() override;
+  bool HasWindowRenderer() const final { return !!mWindowRenderer; }
+
+  // A remote compositor session tied to this window has been lost and IPC
+  // messages will no longer work. The widget must clean up any lingering
+  // resources and possibly schedule another paint.
+  //
+  // A reference to the session object is held until this function has
+  // returned. Callers should hold a reference to the widget, since this
+  // function could deallocate the widget if it is unparented.
+  virtual void NotifyCompositorSessionLost(
+      mozilla::layers::CompositorSession* aSession);
+
+  already_AddRefed<mozilla::CompositorVsyncDispatcher>
+  GetCompositorVsyncDispatcher();
+  virtual void CreateCompositorVsyncDispatcher();
+  virtual void CreateCompositor();
+  virtual void CreateCompositor(int aWidth, int aHeight);
+  virtual void SetCompositorWidgetDelegate(CompositorWidgetDelegate*) {}
+  void PrepareWindowEffects() override {}
+  void UpdateThemeGeometries(
+      const nsTArray<ThemeGeometry>& aThemeGeometries) override {}
+  void SetModal(bool aModal) override {}
+  uint32_t GetMaxTouchPoints() const override;
+  void SetWindowClass(const nsAString& xulWinType, const nsAString& xulWinClass,
+                      const nsAString& xulWinName) override {}
+  // Return whether this widget interprets parameters to Move and Resize APIs
+  // as "desktop pixels" rather than "device pixels", and therefore
+  // applies its GetDefaultScale() value to them before using them as mBounds
+  // etc (which are always stored in device pixels).
+  // Note that APIs that -get- the widget's position/size/bounds, rather than
+  // -setting- them (i.e. moving or resizing the widget) will always return
+  // values in the widget's device pixels.
+  bool BoundsUseDesktopPixels() const {
+    return mWindowType <= WindowType::Popup;
+  }
+  // Default implementation, to be overridden by platforms where desktop coords
+  // are virtualized and may not correspond to device pixels on the screen.
+  mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale() override {
+    return mozilla::DesktopToLayoutDeviceScale(1.0);
+  }
+  mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScaleByScreen()
+      override;
+
+  void ConstrainPosition(DesktopIntPoint&) override {}
+  void MoveClient(const DesktopPoint& aOffset) override;
+  void ResizeClient(const DesktopSize& aSize, bool aRepaint) override;
+  void ResizeClient(const DesktopRect& aRect, bool aRepaint) override;
+  LayoutDeviceIntRect GetBounds() override;
+  LayoutDeviceIntRect GetClientBounds() override;
+  LayoutDeviceIntRect GetScreenBounds() override;
+  [[nodiscard]] nsresult GetRestoredBounds(LayoutDeviceIntRect& aRect) override;
+  nsresult SetNonClientMargins(const LayoutDeviceIntMargin&) override;
+  LayoutDeviceIntPoint GetClientOffset() override;
+  void EnableDragDrop(bool aEnable) override{};
+  nsresult AsyncEnableDragDrop(bool aEnable) override;
+  void SetResizeMargin(mozilla::LayoutDeviceIntCoord aResizeMargin) override;
+  [[nodiscard]] nsresult GetAttention(int32_t aCycleCount) override {
+    return NS_OK;
+  }
+  bool HasPendingInputEvent() override;
+  void SetIcon(const nsAString& aIconSpec) override {}
+  bool ShowsResizeIndicator(LayoutDeviceIntRect* aResizerRect) override;
+  void FreeNativeData(void* data, uint32_t aDataType) override {}
+  nsresult ActivateNativeMenuItemAt(const nsAString& indexString) override {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+  nsresult ForceUpdateNativeMenuAt(const nsAString& indexString) override {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+  nsresult NotifyIME(const IMENotification& aIMENotification) final;
+  [[nodiscard]] nsresult AttachNativeKeyEvent(
+      mozilla::WidgetKeyboardEvent& aEvent) override {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+  bool ComputeShouldAccelerate();
+  virtual bool WidgetTypeSupportsAcceleration() { return true; }
+  [[nodiscard]] nsresult OnDefaultButtonLoaded(
+      const LayoutDeviceIntRect& aButtonRect) override {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+  already_AddRefed<nsIWidget> CreateChild(
+      const LayoutDeviceIntRect& aRect, InitData* aInitData = nullptr,
+      bool aForceUseIWidgetParent = false) override;
+  void AttachViewToTopLevel(bool aUseAttachedEvents) override;
+  nsIWidgetListener* GetAttachedWidgetListener() const override;
+  void SetAttachedWidgetListener(nsIWidgetListener* aListener) override;
+  nsIWidgetListener* GetPreviouslyAttachedWidgetListener() override;
+  void SetPreviouslyAttachedWidgetListener(nsIWidgetListener*) override;
+  NativeIMEContext GetNativeIMEContext() override;
+  TextEventDispatcher* GetTextEventDispatcher() final;
+  TextEventDispatcherListener* GetNativeTextEventDispatcherListener() override;
+  void ZoomToRect(const uint32_t& aPresShellId,
+                  const ScrollableLayerGuid::ViewID& aViewId,
+                  const CSSRect& aRect, const uint32_t& aFlags) override;
+
+  // Dispatch an event that must be first be routed through APZ.
+  ContentAndAPZEventStatus DispatchInputEvent(
+      mozilla::WidgetInputEvent* aEvent) override;
+  void DispatchEventToAPZOnly(mozilla::WidgetInputEvent* aEvent) override;
+
+  bool DispatchWindowEvent(mozilla::WidgetGUIEvent& event) override;
+
+  void SetConfirmedTargetAPZC(
+      uint64_t aInputBlockId,
+      const nsTArray<ScrollableLayerGuid>& aTargets) const override;
+
+  void UpdateZoomConstraints(
+      const uint32_t& aPresShellId, const ScrollableLayerGuid::ViewID& aViewId,
+      const mozilla::Maybe<ZoomConstraints>& aConstraints) override;
+
+  bool AsyncPanZoomEnabled() const override;
+
+  void SwipeFinished() override;
+  void ReportSwipeStarted(uint64_t aInputBlockId, bool aStartSwipe) override;
+  void TrackScrollEventAsSwipe(const mozilla::PanGestureInput& aSwipeStartEvent,
+                               uint32_t aAllowedDirections,
+                               uint64_t aInputBlockId);
+  struct SwipeInfo {
+    bool wantsSwipe;
+    uint32_t allowedDirections;
+  };
+  SwipeInfo SendMayStartSwipe(const mozilla::PanGestureInput& aSwipeStartEvent);
+  // Returns a WidgetWheelEvent which needs to be handled by APZ regardless of
+  // whether |aPanInput| event was used for SwipeTracker or not.
+  mozilla::WidgetWheelEvent MayStartSwipeForAPZ(
+      const mozilla::PanGestureInput& aPanInput,
+      const mozilla::layers::APZEventResult& aApzResult);
+
+  // Returns true if |aPanInput| event was used for SwipeTracker, false
+  // otherwise.
+  bool MayStartSwipeForNonAPZ(const mozilla::PanGestureInput& aPanInput);
+
+  void NotifyWindowDestroyed();
+  void NotifySizeMoveDone();
+
+  using ByMoveToRect = nsIWidgetListener::ByMoveToRect;
+  void NotifyWindowMoved(int32_t aX, int32_t aY,
+                         ByMoveToRect = ByMoveToRect::No);
+
+  // Should be called by derived implementations to notify on system color and
+  // theme changes.
+  void NotifyThemeChanged(mozilla::widget::ThemeChangeKind);
+
+#ifdef ACCESSIBILITY
+  // Get the accessible for the window.
+  mozilla::a11y::LocalAccessible* GetRootAccessible();
+#endif
+
+  // Return true if this is a simple widget (that is typically not worth
+  // accelerating)
+  bool IsSmallPopup() const;
+
+  PopupLevel GetPopupLevel() { return mPopupLevel; }
+
+  // return true if this is a popup widget with a native titlebar
+  bool IsPopupWithTitleBar() const {
+    return (mWindowType == WindowType::Popup &&
+            mBorderStyle != BorderStyle::Default &&
+            mBorderStyle & BorderStyle::Title);
+  }
+
+  void ReparentNativeWidget(nsIWidget* aNewParent) override {}
+
+  const SizeConstraints GetSizeConstraints() override;
+  void SetSizeConstraints(const SizeConstraints& aConstraints) override;
+
+  void StartAsyncScrollbarDrag(const AsyncDragMetrics& aDragMetrics) override;
+
+  bool StartAsyncAutoscroll(const ScreenPoint& aAnchorLocation,
+                            const ScrollableLayerGuid& aGuid) override;
+
+  void StopAsyncAutoscroll(const ScrollableLayerGuid& aGuid) override;
+
+  mozilla::layers::LayersId GetRootLayerTreeId() override;
+
+  /**
+   * Use this when GetLayerManager() returns a BasicLayerManager
+   * (nsBaseWidget::GetLayerManager() does). This sets up the widget's
+   * layer manager to temporarily render into aTarget.
+   *
+   * |aNaturalWidgetBounds| is the un-rotated bounds of |aWidget|.
+   * |aRotation| is the "virtual rotation" to apply when rendering to
+   * the target.  When |aRotation| is ROTATION_0,
+   * |aNaturalWidgetBounds| is not used.
+   */
+  class AutoLayerManagerSetup {
+   public:
+    AutoLayerManagerSetup(nsBaseWidget* aWidget, gfxContext* aTarget,
+                          BufferMode aDoubleBuffering);
+    ~AutoLayerManagerSetup();
+
+   private:
+    nsBaseWidget* mWidget;
+    mozilla::FallbackRenderer* mRenderer = nullptr;
+  };
+  friend class AutoLayerManagerSetup;
+
+  virtual bool ShouldUseOffMainThreadCompositing();
+
+  static nsIRollupListener* GetActiveRollupListener();
+
+  void Shutdown();
+
+  void QuitIME();
+
+  // These functions should be called at the start and end of a "live" widget
+  // resize (i.e. when the window contents are repainting during the resize,
+  // such as when the user drags a window border). It will suppress the
+  // displayport during the live resize to avoid unneccessary overpainting.
+  void NotifyLiveResizeStarted();
+  void NotifyLiveResizeStopped();
+
+#if defined(MOZ_WIDGET_ANDROID)
+  void RecvToolbarAnimatorMessageFromCompositor(int32_t) override{};
+  void UpdateRootFrameMetrics(const ScreenPoint& aScrollOffset,
+                              const CSSToScreenScale& aZoom) override{};
+  void RecvScreenPixels(mozilla::ipc::Shmem&& aMem, const ScreenIntSize& aSize,
+                        bool aNeedsYFlip) override{};
+#endif
+
+  virtual void LocalesChanged() {}
+
+  virtual void NotifyOcclusionState(mozilla::widget::OcclusionState aState) {}
+
+ protected:
+  // These are methods for CompositorWidgetWrapper, and should only be
+  // accessed from that class. Derived widgets can choose which methods to
+  // implement, or none if supporting out-of-process compositing.
+  virtual bool PreRender(mozilla::widget::WidgetRenderingContext* aContext) {
+    return true;
+  }
+  virtual void PostRender(mozilla::widget::WidgetRenderingContext* aContext) {}
+  virtual RefPtr<mozilla::layers::NativeLayerRoot> GetNativeLayerRoot() {
+    return nullptr;
+  }
+  virtual already_AddRefed<DrawTarget> StartRemoteDrawing();
+  virtual already_AddRefed<DrawTarget> StartRemoteDrawingInRegion(
+      const LayoutDeviceIntRegion& aInvalidRegion, BufferMode* aBufferMode) {
+    return StartRemoteDrawing();
+  }
+  virtual void EndRemoteDrawing() {}
+  virtual void EndRemoteDrawingInRegion(
+      DrawTarget* aDrawTarget, const LayoutDeviceIntRegion& aInvalidRegion) {
+    EndRemoteDrawing();
+  }
+  virtual void CleanupRemoteDrawing() {}
+  virtual void CleanupWindowEffects() {}
+  virtual bool InitCompositor(mozilla::layers::Compositor* aCompositor) {
+    return true;
+  }
+  virtual uint32_t GetGLFrameBufferFormat();
+  virtual bool CompositorInitiallyPaused() { return false; }
+
+ protected:
+  void ResolveIconName(const nsAString& aIconName, const nsAString& aIconSuffix,
+                       nsIFile** aResult);
+  virtual void OnDestroy();
+  void BaseCreate(nsIWidget* aParent, InitData* aInitData);
+
+  virtual void ConfigureAPZCTreeManager();
+  virtual void ConfigureAPZControllerThread();
+  virtual already_AddRefed<GeckoContentController>
+  CreateRootContentController();
+
+  // Dispatch an event that has already been routed through APZ.
+  nsEventStatus ProcessUntransformedAPZEvent(
+      mozilla::WidgetInputEvent* aEvent,
+      const mozilla::layers::APZEventResult& aApzResult);
+
+  nsresult SynthesizeNativeKeyEvent(int32_t aNativeKeyboardLayout,
+                                    int32_t aNativeKeyCode,
+                                    uint32_t aModifierFlags,
+                                    const nsAString& aCharacters,
+                                    const nsAString& aUnmodifiedCharacters,
+                                    nsIObserver* aObserver) override {
+    mozilla::widget::AutoObserverNotifier notifier(aObserver, "keyevent");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult SynthesizeNativeMouseEvent(LayoutDeviceIntPoint aPoint,
+                                      NativeMouseMessage aNativeMessage,
+                                      mozilla::MouseButton aButton,
+                                      nsIWidget::Modifiers aModifierFlags,
+                                      nsIObserver* aObserver) override {
+    mozilla::widget::AutoObserverNotifier notifier(aObserver, "mouseevent");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
+                                     nsIObserver* aObserver) override {
+    mozilla::widget::AutoObserverNotifier notifier(aObserver, "mouseevent");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult SynthesizeNativeMouseScrollEvent(
+      LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage, double aDeltaX,
+      double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+      uint32_t aAdditionalFlags, nsIObserver* aObserver) override {
+    mozilla::widget::AutoObserverNotifier notifier(aObserver,
+                                                   "mousescrollevent");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult SynthesizeNativeTouchPoint(uint32_t aPointerId,
+                                      TouchPointerState aPointerState,
+                                      LayoutDeviceIntPoint aPoint,
+                                      double aPointerPressure,
+                                      uint32_t aPointerOrientation,
+                                      nsIObserver* aObserver) override {
+    mozilla::widget::AutoObserverNotifier notifier(aObserver, "touchpoint");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult SynthesizeNativeTouchPadPinch(TouchpadGesturePhase aEventPhase,
+                                         float aScale,
+                                         LayoutDeviceIntPoint aPoint,
+                                         int32_t aModifierFlags) override {
+    MOZ_RELEASE_ASSERT(
+        false, "This method is not implemented on the current platform");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult SynthesizeNativePenInput(uint32_t aPointerId,
+                                    TouchPointerState aPointerState,
+                                    LayoutDeviceIntPoint aPoint,
+                                    double aPressure, uint32_t aRotation,
+                                    int32_t aTiltX, int32_t aTiltY,
+                                    int32_t aButton,
+                                    nsIObserver* aObserver) override {
+    MOZ_RELEASE_ASSERT(
+        false, "This method is not implemented on the current platform");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult SynthesizeNativeTouchpadDoubleTap(LayoutDeviceIntPoint aPoint,
+                                             uint32_t aModifierFlags) override {
+    MOZ_RELEASE_ASSERT(
+        false, "This method is not implemented on the current platform");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult SynthesizeNativeTouchpadPan(TouchpadGesturePhase aEventPhase,
+                                       LayoutDeviceIntPoint aPoint,
+                                       double aDeltaX, double aDeltaY,
+                                       int32_t aModifierFlags,
+                                       nsIObserver* aObserver) override {
+    MOZ_RELEASE_ASSERT(
+        false, "This method is not implemented on the current platform");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  /**
+   * GetPseudoIMEContext() returns pseudo IME context when TextEventDispatcher
+   * has non-native input transaction.  Otherwise, returns nullptr.
+   */
+  void* GetPseudoIMEContext();
+
+ protected:
+  virtual already_AddRefed<nsIWidget> AllocateChildPopupWidget() {
+    return nsIWidget::CreateChildWindow();
+  }
+
+  WindowRenderer* CreateFallbackRenderer();
+
+  PopupType GetPopupType() const { return mPopupType; }
+
+  bool HasRemoteContent() const { return mHasRemoteContent; }
+
+  /**
+   * Apply the current size constraints to the given size.
+   *
+   * @param aWidth width to constrain
+   * @param aHeight height to constrain
+   */
+  void ConstrainSize(int32_t* aWidth, int32_t* aHeight) override {
+    SizeConstraints c = GetSizeConstraints();
+    *aWidth = std::max(c.mMinSize.width, std::min(c.mMaxSize.width, *aWidth));
+    *aHeight =
+        std::max(c.mMinSize.height, std::min(c.mMaxSize.height, *aHeight));
+  }
+
+  CompositorBridgeChild* GetRemoteRenderer() override;
+
+  void ClearCachedWebrenderResources() override;
+
+  void ClearWebrenderAnimationResources() override;
+
+  bool SetNeedFastSnaphot() override;
+
+  /**
+   * Notify the widget that this window is being used with OMTC.
+   */
+  virtual void WindowUsesOMTC() {}
+  virtual void RegisterTouchWindow() {}
+
+  mozilla::dom::Document* GetDocument() const;
+
+  void EnsureTextEventDispatcher();
+
+  // Notify the compositor that a device reset has occurred.
+  void OnRenderingDeviceReset();
+
+  bool UseAPZ();
+
+  bool AllowWebRenderForThisWindow();
+
+  /**
+   * For widgets that support synthesizing native touch events, this function
+   * can be used to manage the current state of synthetic pointers. Each widget
+   * must maintain its own MultiTouchInput instance and pass it in as the state,
+   * along with the desired parameters for the changes. This function returns
+   * a new MultiTouchInput object that is ready to be dispatched.
+   */
+  mozilla::MultiTouchInput UpdateSynthesizedTouchState(
+      mozilla::MultiTouchInput* aState, mozilla::TimeStamp aTimeStamp,
+      uint32_t aPointerId, TouchPointerState aPointerState,
+      LayoutDeviceIntPoint aPoint, double aPointerPressure,
+      uint32_t aPointerOrientation);
+
+  /**
+   * Dispatch the given MultiTouchInput through APZ to Gecko (if APZ is enabled)
+   * or directly to gecko (if APZ is not enabled). This function must only
+   * be called from the main thread, and if APZ is enabled, that must also be
+   * the APZ controller thread.
+   */
+  void DispatchTouchInput(
+      mozilla::MultiTouchInput& aInput,
+      uint16_t aInputSource =
+          mozilla::dom::MouseEvent_Binding::MOZ_SOURCE_TOUCH);
+
+  /**
+   * Dispatch the given PanGestureInput through APZ to Gecko (if APZ is enabled)
+   * or directly to gecko (if APZ is not enabled). This function must only
+   * be called from the main thread, and if APZ is enabled, that must also be
+   * the APZ controller thread.
+   */
+  void DispatchPanGestureInput(mozilla::PanGestureInput& aInput);
+  void DispatchPinchGestureInput(mozilla::PinchGestureInput& aInput);
+
+  static bool ConvertStatus(nsEventStatus aStatus) {
+    return aStatus == nsEventStatus_eConsumeNoDefault;
+  }
+
+ protected:
+  // Returns whether compositing should use an external surface size.
+  virtual bool UseExternalCompositingSurface() const { return false; }
+
+  /**
+   * Starts the OMTC compositor destruction sequence.
+   *
+   * When this function returns, the compositor should not be
+   * able to access the opengl context anymore.
+   * It is safe to call it several times if platform implementations
+   * require the compositor to be destroyed before ~nsBaseWidget is
+   * reached (This is the case with gtk2 for instance).
+   */
+  virtual void DestroyCompositor();
+  void DestroyLayerManager();
+  void ReleaseContentController();
+  void RevokeTransactionIdAllocator();
+
+  void FreeShutdownObserver();
+  void FreeLocalesChangedObserver();
+
+  bool IsPIPWindow() const { return mIsPIPWindow; };
+
+  nsIWidgetListener* mWidgetListener;
+  nsIWidgetListener* mAttachedWidgetListener;
+  nsIWidgetListener* mPreviouslyAttachedWidgetListener;
+  RefPtr<WindowRenderer> mWindowRenderer;
+  RefPtr<CompositorSession> mCompositorSession;
+  RefPtr<CompositorBridgeChild> mCompositorBridgeChild;
+
+  mozilla::UniquePtr<mozilla::Mutex> mCompositorVsyncDispatcherLock;
+  RefPtr<mozilla::CompositorVsyncDispatcher> mCompositorVsyncDispatcher;
+
+  RefPtr<IAPZCTreeManager> mAPZC;
+  RefPtr<GeckoContentController> mRootContentController;
+  RefPtr<APZEventState> mAPZEventState;
+  RefPtr<WidgetShutdownObserver> mShutdownObserver;
+  RefPtr<LocalesChangedObserver> mLocalesChangedObserver;
+  RefPtr<TextEventDispatcher> mTextEventDispatcher;
+  RefPtr<mozilla::SwipeTracker> mSwipeTracker;
+  mozilla::UniquePtr<mozilla::SwipeEventQueue> mSwipeEventQueue;
+  Cursor mCursor;
+  bool mCustomCursorAllowed = true;
+  BorderStyle mBorderStyle;
+  LayoutDeviceIntRect mBounds;
+  bool mIsTiled;
+  PopupLevel mPopupLevel;
+  PopupType mPopupType;
+  SizeConstraints mSizeConstraints;
+  bool mHasRemoteContent;
+
+  struct FullscreenSavedState {
+    DesktopRect windowRect;
+    DesktopRect screenRect;
+  };
+  mozilla::Maybe<FullscreenSavedState> mSavedBounds;
+
+  bool mUpdateCursor;
+  bool mUseAttachedEvents;
+  bool mIMEHasFocus;
+  bool mIMEHasQuit;
+  bool mIsFullyOccluded;
+  bool mNeedFastSnaphot;
+  // This flag is only used when APZ is off. It indicates that the current pan
+  // gesture was processed as a swipe. Sometimes the swipe animation can finish
+  // before momentum events of the pan gesture have stopped firing, so this
+  // flag tells us that we shouldn't allow the remaining events to cause
+  // scrolling. It is reset to false once a new gesture starts (as indicated by
+  // a PANGESTURE_(MAY)START event).
+  bool mCurrentPanGestureBelongsToSwipe;
+
+  // It's PictureInPicture window.
+  bool mIsPIPWindow : 1;
+
+  struct InitialZoomConstraints {
+    InitialZoomConstraints(const uint32_t& aPresShellID,
+                           const ScrollableLayerGuid::ViewID& aViewID,
+                           const ZoomConstraints& aConstraints)
+        : mPresShellID(aPresShellID),
+          mViewID(aViewID),
+          mConstraints(aConstraints) {}
+
+    uint32_t mPresShellID;
+    ScrollableLayerGuid::ViewID mViewID;
+    ZoomConstraints mConstraints;
+  };
+
+  mozilla::Maybe<InitialZoomConstraints> mInitialZoomConstraints;
+
+  // This points to the resize listeners who have been notified that a live
+  // resize is in progress. This should always be empty when a live-resize is
+  // not in progress.
+  nsTArray<RefPtr<mozilla::LiveResizeListener>> mLiveResizeListeners;
+
+#ifdef DEBUG
+ protected:
+  static nsAutoString debug_GuiEventToString(
+      mozilla::WidgetGUIEvent* aGuiEvent);
+
+  static void debug_DumpInvalidate(FILE* aFileOut, nsIWidget* aWidget,
+                                   const LayoutDeviceIntRect* aRect,
+                                   const char* aWidgetName, int32_t aWindowID);
+
+  static void debug_DumpEvent(FILE* aFileOut, nsIWidget* aWidget,
+                              mozilla::WidgetGUIEvent* aGuiEvent,
+                              const char* aWidgetName, int32_t aWindowID);
+
+  static void debug_DumpPaintEvent(FILE* aFileOut, nsIWidget* aWidget,
+                                   const nsIntRegion& aPaintEvent,
+                                   const char* aWidgetName, int32_t aWindowID);
+
+  static bool debug_GetCachedBoolPref(const char* aPrefName);
+#endif
+
+ private:
+  already_AddRefed<mozilla::layers::WebRenderLayerManager>
+  CreateCompositorSession(int aWidth, int aHeight,
+                          mozilla::layers::CompositorOptions* aOptionsOut);
+};
+
+#endif  // nsBaseWidget_h__
diff --git a/widget/nsCUPSShim.cpp b/widget/nsCUPSShim.cpp
new file mode 100644
index 0000000000..d999a1be17
--- /dev/null
+++ b/widget/nsCUPSShim.cpp
@@ -0,0 +1,76 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ex: set tabstop=8 softtabstop=2 shiftwidth=2 expandtab: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsDebug.h"
+#include "nsString.h"
+#include "nsCUPSShim.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/Logging.h"
+#include "prlink.h"
+
+#ifdef CUPS_SHIM_RUNTIME_LINK
+
+mozilla::LazyLogModule gCupsLinkLog("CupsLink");
+
+#  define DEBUG_LOG(...) \
+    MOZ_LOG(gCupsLinkLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+
+// TODO: This is currently pointless as we always use the compile-time linked
+// version of CUPS, but in the future this may become a configure option.
+// We also cannot use NSPR's library suffix support, since that cannot handle
+// version number suffixes.
+#  ifdef XP_MACOSX
+static const char gCUPSLibraryName[] = "libcups.2.dylib";
+#  else
+static const char gCUPSLibraryName[] = "libcups.so.2";
+#  endif
+
+static bool LoadCupsFunc(PRLibrary* aLib, void** aDest, const char* const aName,
+                         nsCUPSShim::Optional aOptional) {
+  *aDest = PR_FindSymbol(aLib, aName);
+  if (!*aDest) {
+    DEBUG_LOG("%s not found in CUPS library", aName);
+    return bool(aOptional);
+  }
+  return true;
+}
+
+nsCUPSShim::nsCUPSShim() {
+  mCupsLib = PR_LoadLibrary(gCUPSLibraryName);
+  if (!mCupsLib) {
+    DEBUG_LOG("CUPS library not found");
+    return;
+  }
+
+  bool success = true;
+
+  // This is a macro so that it could also load from libcups if we are
+  // configured to use it as a compile-time dependency.
+  //
+  // We try to load all functions even if some fail so that we get the debug log
+  // unconditionally.
+#  define CUPS_SHIM_LOAD(opt_, fn_) \
+    success |=                      \
+        LoadCupsFunc(mCupsLib, reinterpret_cast<void**>(&fn_), #fn_, opt_);
+  CUPS_SHIM_ALL_FUNCS(CUPS_SHIM_LOAD)
+#  undef CUPS_SHIM_LOAD
+
+  if (!success) {
+#  ifndef MOZ_TSAN
+    // With TSan, we cannot unload libcups once we have loaded it because
+    // TSan does not support unloading libraries that are matched from its
+    // suppression list. Hence we just keep the library loaded in TSan builds.
+    PR_UnloadLibrary(mCupsLib);
+#  endif
+    mCupsLib = nullptr;
+    return;
+  }
+
+  // Set mInitOkay only if all cups functions are loaded successfully.
+  mInitOkay = true;
+}
+
+#endif
diff --git a/widget/nsCUPSShim.h b/widget/nsCUPSShim.h
new file mode 100644
index 0000000000..8ab00a48ad
--- /dev/null
+++ b/widget/nsCUPSShim.h
@@ -0,0 +1,96 @@
+/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ex: set tabstop=8 softtabstop=2 shiftwidth=2 expandtab: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsCUPSShim_h___
+#define nsCUPSShim_h___
+
+#include <cups/cups.h>
+#include "mozilla/Atomics.h"
+#include "mozilla/Mutex.h"
+
+// TODO: This should be a configure option, ideally.
+#ifndef XP_MACOSX
+#  define CUPS_SHIM_RUNTIME_LINK
+#endif
+
+struct PRLibrary;
+
+class nsCUPSShim {
+ public:
+#ifdef CUPS_SHIM_RUNTIME_LINK
+  nsCUPSShim();
+  bool InitOkay() { return mInitOkay; }
+#else
+  nsCUPSShim() = default;
+  bool InitOkay() { return true; }
+#endif
+
+  // We allow some functions to be missing, to degrade as gracefully as possible
+  // for older versions of CUPS.
+  //
+  // The current target is CUPS 1.6 (bug 1701019).
+  enum class Optional : bool { No, Yes };
+
+  /**
+   * Function pointers for supported functions. These are only
+   * valid after successful initialization.
+   */
+#define CUPS_SHIM_ALL_FUNCS(X)              \
+  X(Optional::No, cupsAddOption)            \
+  X(Optional::No, cupsCheckDestSupported)   \
+  X(Optional::No, cupsConnectDest)          \
+  X(Optional::No, cupsCopyDest)             \
+  X(Optional::No, cupsCopyDestInfo)         \
+  X(Optional::No, cupsDoRequest)            \
+  X(Optional::No, cupsEnumDests)            \
+  X(Optional::No, cupsFreeDestInfo)         \
+  X(Optional::No, cupsFreeDests)            \
+  X(Optional::No, cupsGetDestMediaByName)   \
+  X(Optional::Yes, cupsFindDestDefault)     \
+  X(Optional::Yes, cupsGetDestMediaDefault) \
+  X(Optional::Yes, cupsGetDestMediaCount)   \
+  X(Optional::Yes, cupsGetDestMediaByIndex) \
+  X(Optional::Yes, cupsLocalizeDestMedia)   \
+  X(Optional::No, cupsGetDest)              \
+  X(Optional::No, cupsGetDests)             \
+  X(Optional::No, cupsGetDests2)            \
+  X(Optional::No, cupsGetNamedDest)         \
+  X(Optional::No, cupsGetOption)            \
+  X(Optional::No, cupsServer)               \
+  X(Optional::Yes, httpAddrPort)            \
+  X(Optional::No, httpClose)                \
+  X(Optional::No, httpGetHostname)          \
+  X(Optional::Yes, httpGetAddress)          \
+  X(Optional::No, ippAddString)             \
+  X(Optional::No, ippAddStrings)            \
+  X(Optional::No, ippDelete)                \
+  X(Optional::No, ippFindAttribute)         \
+  X(Optional::No, ippGetCount)              \
+  X(Optional::No, ippGetString)             \
+  X(Optional::No, ippNewRequest)            \
+  X(Optional::No, ippPort)
+
+#ifdef CUPS_SHIM_RUNTIME_LINK
+  // Define a single field which holds a function pointer.
+#  define CUPS_SHIM_FUNC_DECL(opt_, fn_) decltype(::fn_)* fn_ = nullptr;
+#else
+  // Define a static constexpr function pointer. GCC can sometimes optimize
+  // away the pointer fetch for this.
+#  define CUPS_SHIM_FUNC_DECL(opt_, fn_) \
+    static constexpr decltype(::fn_)* const fn_ = ::fn_;
+#endif
+
+  CUPS_SHIM_ALL_FUNCS(CUPS_SHIM_FUNC_DECL)
+#undef CUPS_SHIM_FUNC_DECL
+
+#ifdef CUPS_SHIM_RUNTIME_LINK
+ private:
+  bool mInitOkay = false;
+  PRLibrary* mCupsLib = nullptr;
+#endif
+};
+
+#endif /* nsCUPSShim_h___ */
diff --git a/widget/nsClipboardHelper.cpp b/widget/nsClipboardHelper.cpp
new file mode 100644
index 0000000000..3439adef48
--- /dev/null
+++ b/widget/nsClipboardHelper.cpp
@@ -0,0 +1,123 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsClipboardHelper.h"
+
+// basics
+#include "nsComponentManagerUtils.h"
+#include "nsCOMPtr.h"
+#include "nsXPCOM.h"
+#include "nsISupportsPrimitives.h"
+#include "nsServiceManagerUtils.h"
+
+// helpers
+#include "nsIClipboard.h"
+#include "mozilla/dom/Document.h"
+#include "nsITransferable.h"
+#include "nsReadableUtils.h"
+
+NS_IMPL_ISUPPORTS(nsClipboardHelper, nsIClipboardHelper)
+
+/*****************************************************************************
+ * nsClipboardHelper ctor / dtor
+ *****************************************************************************/
+
+nsClipboardHelper::nsClipboardHelper() = default;
+
+nsClipboardHelper::~nsClipboardHelper() {
+  // no members, nothing to destroy
+}
+
+/*****************************************************************************
+ * nsIClipboardHelper methods
+ *****************************************************************************/
+
+NS_IMETHODIMP
+nsClipboardHelper::CopyStringToClipboard(const nsAString& aString,
+                                         int32_t aClipboardID,
+                                         SensitiveData aSensitive) {
+  nsresult rv;
+
+  // get the clipboard
+  nsCOMPtr<nsIClipboard> clipboard(
+      do_GetService("@mozilla.org/widget/clipboard;1", &rv));
+  NS_ENSURE_SUCCESS(rv, rv);
+  NS_ENSURE_TRUE(clipboard, NS_ERROR_FAILURE);
+
+  // don't go any further if they're asking for the selection
+  // clipboard on a platform which doesn't support it (i.e., unix)
+  if (nsIClipboard::kSelectionClipboard == aClipboardID &&
+      !clipboard->IsClipboardTypeSupported(nsIClipboard::kSelectionClipboard)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // don't go any further if they're asking for the find clipboard on a platform
+  // which doesn't support it (i.e., non-osx)
+  if (nsIClipboard::kFindClipboard == aClipboardID &&
+      !clipboard->IsClipboardTypeSupported(nsIClipboard::kFindClipboard)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // create a transferable for putting data on the clipboard
+  nsCOMPtr<nsITransferable> trans(
+      do_CreateInstance("@mozilla.org/widget/transferable;1", &rv));
+  NS_ENSURE_SUCCESS(rv, rv);
+  NS_ENSURE_TRUE(trans, NS_ERROR_FAILURE);
+
+  trans->Init(nullptr);
+  if (aSensitive == SensitiveData::Sensitive) {
+    trans->SetIsPrivateData(true);
+  }
+
+  // Add the text data flavor to the transferable
+  rv = trans->AddDataFlavor(kTextMime);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // get wStrings to hold clip data
+  nsCOMPtr<nsISupportsString> data(
+      do_CreateInstance("@mozilla.org/supports-string;1", &rv));
+  NS_ENSURE_SUCCESS(rv, rv);
+  NS_ENSURE_TRUE(data, NS_ERROR_FAILURE);
+
+  // populate the string
+  rv = data->SetData(aString);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Pass the data object as |nsISupports| so that when the transferable holds
+  // onto it, it will addref the correct interface.
+  rv = trans->SetTransferData(kTextMime, ToSupports(data));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // put the transferable on the clipboard
+  rv = clipboard->SetData(trans, nullptr, aClipboardID);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsClipboardHelper::CopyString(const nsAString& aString,
+                              SensitiveData aSensitive) {
+  nsresult rv;
+
+  // copy to the global clipboard. it's bad if this fails in any way.
+  rv = CopyStringToClipboard(aString, nsIClipboard::kGlobalClipboard,
+                             aSensitive);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // unix also needs us to copy to the selection clipboard. this will
+  // fail in CopyStringToClipboard if we're not on a platform that
+  // supports the selection clipboard. (this could have been #ifdef
+  // XP_UNIX, but using the IsClipboardTypeSupported call is the more correct
+  // thing to do.
+  //
+  // if this fails in any way other than "not being unix", we'll get
+  // the assertion we need in CopyStringToClipboard, and we needn't
+  // assert again here.
+  CopyStringToClipboard(aString, nsIClipboard::kSelectionClipboard, aSensitive);
+
+  return NS_OK;
+}
diff --git a/widget/nsClipboardHelper.h b/widget/nsClipboardHelper.h
new file mode 100644
index 0000000000..b9954e7bd4
--- /dev/null
+++ b/widget/nsClipboardHelper.h
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsClipboardHelper_h__
+#define nsClipboardHelper_h__
+
+// interfaces
+#include "nsIClipboardHelper.h"
+
+// basics
+#include "nsString.h"
+
+/**
+ * impl class for nsIClipboardHelper, a helper for common uses of nsIClipboard.
+ */
+
+class nsClipboardHelper : public nsIClipboardHelper {
+  virtual ~nsClipboardHelper();
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSICLIPBOARDHELPER
+
+  nsClipboardHelper();
+};
+
+#endif  // nsClipboardHelper_h__
diff --git a/widget/nsClipboardProxy.cpp b/widget/nsClipboardProxy.cpp
new file mode 100644
index 0000000000..41f285461b
--- /dev/null
+++ b/widget/nsClipboardProxy.cpp
@@ -0,0 +1,271 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsClipboardProxy.h"
+
+#if defined(ACCESSIBILITY) && defined(XP_WIN)
+#  include "mozilla/a11y/Compatibility.h"
+#endif
+#include "mozilla/ClipboardReadRequestChild.h"
+#include "mozilla/ClipboardWriteRequestChild.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/net/CookieJarSettings.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/dom/WindowGlobalChild.h"
+#include "mozilla/Unused.h"
+#include "nsArrayUtils.h"
+#include "nsBaseClipboard.h"
+#include "nsISupportsPrimitives.h"
+#include "nsCOMPtr.h"
+#include "nsComponentManagerUtils.h"
+#include "nsXULAppAPI.h"
+#include "nsContentUtils.h"
+#include "PermissionMessageUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+NS_IMPL_ISUPPORTS(nsClipboardProxy, nsIClipboard, nsIClipboardProxy)
+
+nsClipboardProxy::nsClipboardProxy() : mClipboardCaps(false, false, false) {}
+
+NS_IMETHODIMP
+nsClipboardProxy::SetData(nsITransferable* aTransferable,
+                          nsIClipboardOwner* anOwner, int32_t aWhichClipboard) {
+#if defined(ACCESSIBILITY) && defined(XP_WIN)
+  a11y::Compatibility::SuppressA11yForClipboardCopy();
+#endif
+
+  ContentChild* child = ContentChild::GetSingleton();
+  IPCTransferable ipcTransferable;
+  nsContentUtils::TransferableToIPCTransferable(aTransferable, &ipcTransferable,
+                                                false, nullptr);
+  child->SendSetClipboard(std::move(ipcTransferable), aWhichClipboard);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsClipboardProxy::AsyncSetData(
+    int32_t aWhichClipboard, nsIAsyncClipboardRequestCallback* aCallback,
+    nsIAsyncSetClipboardData** _retval) {
+  RefPtr<ClipboardWriteRequestChild> request =
+      MakeRefPtr<ClipboardWriteRequestChild>(aCallback);
+  ContentChild::GetSingleton()->SendPClipboardWriteRequestConstructor(
+      request, aWhichClipboard);
+  request.forget(_retval);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsClipboardProxy::GetData(nsITransferable* aTransferable,
+                          int32_t aWhichClipboard,
+                          mozilla::dom::WindowContext* aWindowContext) {
+  MOZ_DIAGNOSTIC_ASSERT(aWindowContext && aWindowContext->IsInProcess(),
+                        "content clipboard reads must be associated with an "
+                        "in-process WindowContext");
+  if (aWindowContext->IsDiscarded()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+  nsTArray<nsCString> types;
+  aTransferable->FlavorsTransferableCanImport(types);
+
+  IPCTransferableData transferable;
+  ContentChild::GetSingleton()->SendGetClipboard(types, aWhichClipboard,
+                                                 aWindowContext, &transferable);
+  return nsContentUtils::IPCTransferableDataToTransferable(
+      transferable, false /* aAddDataFlavor */, aTransferable,
+      false /* aFilterUnknownFlavors */);
+}
+
+namespace {
+
+class AsyncGetClipboardDataProxy final : public nsIAsyncGetClipboardData {
+ public:
+  explicit AsyncGetClipboardDataProxy(ClipboardReadRequestChild* aActor)
+      : mActor(aActor) {
+    MOZ_ASSERT(mActor);
+  }
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIASYNCGETCLIPBOARDDATA
+
+ private:
+  virtual ~AsyncGetClipboardDataProxy() {
+    MOZ_ASSERT(mActor);
+    if (mActor->CanSend()) {
+      PClipboardReadRequestChild::Send__delete__(mActor);
+    }
+  };
+
+  RefPtr<ClipboardReadRequestChild> mActor;
+};
+
+NS_IMPL_ISUPPORTS(AsyncGetClipboardDataProxy, nsIAsyncGetClipboardData)
+
+NS_IMETHODIMP AsyncGetClipboardDataProxy::GetValid(bool* aOutResult) {
+  MOZ_ASSERT(mActor);
+  *aOutResult = mActor->CanSend();
+  return NS_OK;
+}
+
+NS_IMETHODIMP AsyncGetClipboardDataProxy::GetFlavorList(
+    nsTArray<nsCString>& aFlavorList) {
+  MOZ_ASSERT(mActor);
+  aFlavorList.AppendElements(mActor->FlavorList());
+  return NS_OK;
+}
+
+NS_IMETHODIMP AsyncGetClipboardDataProxy::GetData(
+    nsITransferable* aTransferable,
+    nsIAsyncClipboardRequestCallback* aCallback) {
+  if (!aTransferable || !aCallback) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  // Get a list of flavors this transferable can import
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanImport(flavors);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  MOZ_ASSERT(mActor);
+  // If the requested flavor is not in the list, throw an error.
+  for (const auto& flavor : flavors) {
+    if (!mActor->FlavorList().Contains(flavor)) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  if (!mActor->CanSend()) {
+    return aCallback->OnComplete(NS_ERROR_FAILURE);
+  }
+
+  mActor->SendGetData(flavors)->Then(
+      GetMainThreadSerialEventTarget(), __func__,
+      /* resolve */
+      [self = RefPtr{this}, callback = nsCOMPtr{aCallback},
+       transferable = nsCOMPtr{aTransferable}](
+          const IPCTransferableDataOrError& aIpcTransferableDataOrError) {
+        if (aIpcTransferableDataOrError.type() ==
+            IPCTransferableDataOrError::Tnsresult) {
+          MOZ_ASSERT(NS_FAILED(aIpcTransferableDataOrError.get_nsresult()));
+          callback->OnComplete(aIpcTransferableDataOrError.get_nsresult());
+          return;
+        }
+
+        nsresult rv = nsContentUtils::IPCTransferableDataToTransferable(
+            aIpcTransferableDataOrError.get_IPCTransferableData(),
+            false /* aAddDataFlavor */, transferable,
+            false /* aFilterUnknownFlavors */);
+        if (NS_FAILED(rv)) {
+          callback->OnComplete(rv);
+          return;
+        }
+
+        callback->OnComplete(NS_OK);
+      },
+      /* reject */
+      [callback =
+           nsCOMPtr{aCallback}](mozilla::ipc::ResponseRejectReason aReason) {
+        callback->OnComplete(NS_ERROR_FAILURE);
+      });
+
+  return NS_OK;
+}
+
+}  // namespace
+
+NS_IMETHODIMP nsClipboardProxy::AsyncGetData(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard,
+    mozilla::dom::WindowContext* aRequestingWindowContext,
+    nsIPrincipal* aRequestingPrincipal,
+    nsIAsyncClipboardGetCallback* aCallback) {
+  if (!aCallback || !aRequestingPrincipal || aFlavorList.IsEmpty()) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  if (!nsIClipboard::IsClipboardTypeSupported(aWhichClipboard)) {
+    MOZ_CLIPBOARD_LOG("%s: clipboard %d is not supported.", __FUNCTION__,
+                      aWhichClipboard);
+    return NS_ERROR_FAILURE;
+  }
+
+  ContentChild::GetSingleton()
+      ->SendGetClipboardAsync(aFlavorList, aWhichClipboard,
+                              aRequestingWindowContext,
+                              WrapNotNull(aRequestingPrincipal))
+      ->Then(
+          GetMainThreadSerialEventTarget(), __func__,
+          /* resolve */
+          [callback = nsCOMPtr{aCallback}](const PClipboardReadRequestOrError&
+                                               aClipboardReadRequestOrError) {
+            if (aClipboardReadRequestOrError.type() ==
+                PClipboardReadRequestOrError::Tnsresult) {
+              MOZ_ASSERT(
+                  NS_FAILED(aClipboardReadRequestOrError.get_nsresult()));
+              callback->OnError(aClipboardReadRequestOrError.get_nsresult());
+              return;
+            }
+
+            auto asyncGetClipboardData = MakeRefPtr<AsyncGetClipboardDataProxy>(
+                static_cast<ClipboardReadRequestChild*>(
+                    aClipboardReadRequestOrError.get_PClipboardReadRequest()
+                        .AsChild()
+                        .get()));
+
+            callback->OnSuccess(asyncGetClipboardData);
+          },
+          /* reject */
+          [callback = nsCOMPtr{aCallback}](
+              mozilla::ipc::ResponseRejectReason aReason) {
+            callback->OnError(NS_ERROR_FAILURE);
+          });
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsClipboardProxy::EmptyClipboard(int32_t aWhichClipboard) {
+  ContentChild::GetSingleton()->SendEmptyClipboard(aWhichClipboard);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsClipboardProxy::HasDataMatchingFlavors(const nsTArray<nsCString>& aFlavorList,
+                                         int32_t aWhichClipboard,
+                                         bool* aHasType) {
+  *aHasType = false;
+
+  ContentChild::GetSingleton()->SendClipboardHasType(aFlavorList,
+                                                     aWhichClipboard, aHasType);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsClipboardProxy::IsClipboardTypeSupported(int32_t aWhichClipboard,
+                                           bool* aIsSupported) {
+  switch (aWhichClipboard) {
+    case kGlobalClipboard:
+      // We always support the global clipboard.
+      *aIsSupported = true;
+      return NS_OK;
+    case kSelectionClipboard:
+      *aIsSupported = mClipboardCaps.supportsSelectionClipboard();
+      return NS_OK;
+    case kFindClipboard:
+      *aIsSupported = mClipboardCaps.supportsFindClipboard();
+      return NS_OK;
+    case kSelectionCache:
+      *aIsSupported = mClipboardCaps.supportsSelectionCache();
+      return NS_OK;
+  }
+
+  *aIsSupported = false;
+  return NS_OK;
+}
+
+void nsClipboardProxy::SetCapabilities(
+    const ClipboardCapabilities& aClipboardCaps) {
+  mClipboardCaps = aClipboardCaps;
+}
diff --git a/widget/nsClipboardProxy.h b/widget/nsClipboardProxy.h
new file mode 100644
index 0000000000..33b47d90bb
--- /dev/null
+++ b/widget/nsClipboardProxy.h
@@ -0,0 +1,48 @@
+/* -*- Mode: c++; c-basic-offset: 2; tab-width: 20; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NS_CLIPBOARD_PROXY_H
+#define NS_CLIPBOARD_PROXY_H
+
+#include "mozilla/dom/PContent.h"
+#include "nsIClipboard.h"
+
+#define NS_CLIPBOARDPROXY_IID                        \
+  {                                                  \
+    0xa64c82da, 0x7326, 0x4681, {                    \
+      0xa0, 0x95, 0x81, 0x2c, 0xc9, 0x86, 0xe6, 0xde \
+    }                                                \
+  }
+
+// Hack for ContentChild to be able to know that we're an nsClipboardProxy.
+class nsIClipboardProxy : public nsIClipboard {
+ protected:
+  typedef mozilla::dom::ClipboardCapabilities ClipboardCapabilities;
+
+ public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_CLIPBOARDPROXY_IID)
+
+  virtual void SetCapabilities(const ClipboardCapabilities& aClipboardCaps) = 0;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsIClipboardProxy, NS_CLIPBOARDPROXY_IID)
+
+class nsClipboardProxy final : public nsIClipboardProxy {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSICLIPBOARD
+
+  nsClipboardProxy();
+
+  virtual void SetCapabilities(
+      const ClipboardCapabilities& aClipboardCaps) override;
+
+ private:
+  ~nsClipboardProxy() = default;
+
+  ClipboardCapabilities mClipboardCaps;
+};
+
+#endif
diff --git a/widget/nsColorPickerProxy.cpp b/widget/nsColorPickerProxy.cpp
new file mode 100644
index 0000000000..0db2a7bd81
--- /dev/null
+++ b/widget/nsColorPickerProxy.cpp
@@ -0,0 +1,54 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsColorPickerProxy.h"
+
+#include "mozilla/dom/BrowserChild.h"
+
+using namespace mozilla::dom;
+
+NS_IMPL_ISUPPORTS(nsColorPickerProxy, nsIColorPicker)
+
+NS_IMETHODIMP
+nsColorPickerProxy::Init(mozIDOMWindowProxy* aParent, const nsAString& aTitle,
+                         const nsAString& aInitialColor,
+                         const nsTArray<nsString>& aDefaultColors) {
+  BrowserChild* browserChild = BrowserChild::GetFrom(aParent);
+  if (!browserChild) {
+    return NS_ERROR_FAILURE;
+  }
+
+  browserChild->SendPColorPickerConstructor(this, aTitle, aInitialColor,
+                                            aDefaultColors);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsColorPickerProxy::Open(
+    nsIColorPickerShownCallback* aColorPickerShownCallback) {
+  NS_ENSURE_STATE(!mCallback);
+  mCallback = aColorPickerShownCallback;
+
+  SendOpen();
+  return NS_OK;
+}
+
+mozilla::ipc::IPCResult nsColorPickerProxy::RecvUpdate(
+    const nsAString& aColor) {
+  if (mCallback) {
+    mCallback->Update(aColor);
+  }
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult nsColorPickerProxy::Recv__delete__(
+    const nsAString& aColor) {
+  if (mCallback) {
+    mCallback->Done(aColor);
+    mCallback = nullptr;
+  }
+  return IPC_OK();
+}
diff --git a/widget/nsColorPickerProxy.h b/widget/nsColorPickerProxy.h
new file mode 100644
index 0000000000..a06e69aafe
--- /dev/null
+++ b/widget/nsColorPickerProxy.h
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsColorPickerProxy_h
+#define nsColorPickerProxy_h
+
+#include "nsIColorPicker.h"
+
+#include "mozilla/dom/PColorPickerChild.h"
+
+class nsColorPickerProxy final : public nsIColorPicker,
+                                 public mozilla::dom::PColorPickerChild {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSICOLORPICKER
+
+  nsColorPickerProxy() = default;
+
+  virtual mozilla::ipc::IPCResult RecvUpdate(const nsAString& aColor) override;
+  virtual mozilla::ipc::IPCResult Recv__delete__(
+      const nsAString& aColor) override;
+
+ private:
+  ~nsColorPickerProxy() = default;
+
+  nsCOMPtr<nsIColorPickerShownCallback> mCallback;
+  nsString mTitle;
+  nsString mInitialColor;
+};
+
+#endif  // nsColorPickerProxy_h
diff --git a/widget/nsContentProcessWidgetFactory.h b/widget/nsContentProcessWidgetFactory.h
new file mode 100644
index 0000000000..eb2d5a042d
--- /dev/null
+++ b/widget/nsContentProcessWidgetFactory.h
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsContentProcessWidgetFactory_h
+#define nsContentProcessWidgetFactory_h
+
+#include "nsISupports.h"
+#include "nsComponentManagerUtils.h"
+#include "nsServiceManagerUtils.h"
+#include "nsXULAppAPI.h"
+
+#define MAKE_COMPONENT_CHOOSER(name_, parent_, content_, constructor_) \
+  static already_AddRefed<nsISupports> name_() {                       \
+    nsCOMPtr<nsISupports> inst;                                        \
+    if (XRE_IsContentProcess()) {                                      \
+      inst = constructor_(content_);                                   \
+    } else {                                                           \
+      inst = constructor_(parent_);                                    \
+    }                                                                  \
+    return inst.forget();                                              \
+  }
+
+#ifdef MOZ_WIDGET_COCOA
+// This should be `do_GetService`, but test_bug466599.xhtml erroneously uses
+// `createInstance` rather than `getService`, and passes only because doing so
+// bypasses the clipboard contents cache, which does not have the expected
+// wrapping.
+MAKE_COMPONENT_CHOOSER(nsClipboardSelector,
+                       "@mozilla.org/widget/parent/clipboard;1",
+                       "@mozilla.org/widget/content/clipboard;1",
+                       do_CreateInstance)
+#else
+MAKE_COMPONENT_CHOOSER(nsClipboardSelector,
+                       "@mozilla.org/widget/parent/clipboard;1",
+                       "@mozilla.org/widget/content/clipboard;1", do_GetService)
+#endif
+MAKE_COMPONENT_CHOOSER(nsColorPickerSelector,
+                       "@mozilla.org/parent/colorpicker;1",
+                       "@mozilla.org/content/colorpicker;1", do_CreateInstance)
+MAKE_COMPONENT_CHOOSER(nsFilePickerSelector, "@mozilla.org/parent/filepicker;1",
+                       "@mozilla.org/content/filepicker;1", do_CreateInstance)
+MAKE_COMPONENT_CHOOSER(nsScreenManagerSelector,
+                       "@mozilla.org/gfx/parent/screenmanager;1",
+                       "@mozilla.org/gfx/content/screenmanager;1",
+                       do_GetService)
+MAKE_COMPONENT_CHOOSER(nsDragServiceSelector,
+                       "@mozilla.org/widget/parent/dragservice;1",
+                       "@mozilla.org/widget/content/dragservice;1",
+                       do_GetService)
+
+#undef MAKE_COMPONENT_CHOOSER
+
+#endif  // defined nsContentProcessWidgetFactory_h
diff --git a/widget/nsDeviceContextSpecProxy.cpp b/widget/nsDeviceContextSpecProxy.cpp
new file mode 100644
index 0000000000..17a0664ede
--- /dev/null
+++ b/widget/nsDeviceContextSpecProxy.cpp
@@ -0,0 +1,164 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsDeviceContextSpecProxy.h"
+
+#include "gfxASurface.h"
+#include "gfxPlatform.h"
+#include "mozilla/gfx/DrawEventRecorder.h"
+#include "mozilla/gfx/PrintTargetThebes.h"
+#include "mozilla/layout/RemotePrintJobChild.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/Unused.h"
+#include "nsComponentManagerUtils.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
+#include "nsIPrintSettings.h"
+#include "private/pprio.h"
+
+using mozilla::Unused;
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+
+NS_IMPL_ISUPPORTS(nsDeviceContextSpecProxy, nsIDeviceContextSpec)
+
+nsDeviceContextSpecProxy::nsDeviceContextSpecProxy(
+    RemotePrintJobChild* aRemotePrintJob)
+    : mRemotePrintJob(aRemotePrintJob) {}
+nsDeviceContextSpecProxy::~nsDeviceContextSpecProxy() = default;
+
+NS_IMETHODIMP
+nsDeviceContextSpecProxy::Init(nsIPrintSettings* aPrintSettings,
+                               bool aIsPrintPreview) {
+  mPrintSettings = aPrintSettings;
+
+  if (aIsPrintPreview) {
+    return NS_OK;
+  }
+
+  if (!mRemotePrintJob) {
+    NS_WARNING("We can't print via the parent without a RemotePrintJobChild.");
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+already_AddRefed<PrintTarget> nsDeviceContextSpecProxy::MakePrintTarget() {
+  double width, height;
+  mPrintSettings->GetEffectiveSheetSize(&width, &height);
+  if (width <= 0 || height <= 0) {
+    return nullptr;
+  }
+
+  // convert twips to points
+  width /= TWIPS_PER_POINT_FLOAT;
+  height /= TWIPS_PER_POINT_FLOAT;
+
+  RefPtr<gfxASurface> surface =
+      gfxPlatform::GetPlatform()->CreateOffscreenSurface(
+          mozilla::gfx::IntSize::Ceil(width, height),
+          mozilla::gfx::SurfaceFormat::A8R8G8B8_UINT32);
+  if (!surface) {
+    return nullptr;
+  }
+
+  // The type of PrintTarget that we return here shouldn't really matter since
+  // our implementation of GetDrawEventRecorder returns an object, which means
+  // the DrawTarget returned by the PrintTarget will be a
+  // DrawTargetWrapAndRecord. The recording will be serialized and sent over to
+  // the parent process where PrintTranslator::TranslateRecording will call
+  // MakePrintTarget (indirectly via PrintTranslator::CreateDrawTarget) on
+  // whatever type of nsIDeviceContextSpecProxy is created for the platform that
+  // we are running on.  It is that DrawTarget that the recording will be
+  // replayed on to print.
+  // XXX(jwatt): The above isn't quite true.  We do want to use a
+  // PrintTargetRecording here, but we can't until bug 1280324 is figured out
+  // and fixed otherwise we will cause bug 1280181 to happen again.
+  RefPtr<PrintTarget> target = PrintTargetThebes::CreateOrNull(surface);
+
+  return target.forget();
+}
+
+NS_IMETHODIMP
+nsDeviceContextSpecProxy::GetDrawEventRecorder(
+    mozilla::gfx::DrawEventRecorder** aDrawEventRecorder) {
+  MOZ_ASSERT(aDrawEventRecorder);
+  RefPtr<mozilla::gfx::DrawEventRecorder> result = mRecorder;
+  result.forget(aDrawEventRecorder);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDeviceContextSpecProxy::BeginDocument(const nsAString& aTitle,
+                                        const nsAString& aPrintToFileName,
+                                        int32_t aStartPage, int32_t aEndPage) {
+  if (!mRemotePrintJob || mRemotePrintJob->IsDestroyed()) {
+    mRemotePrintJob = nullptr;
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  mRecorder = new mozilla::layout::DrawEventRecorderPRFileDesc();
+  nsresult rv =
+      mRemotePrintJob->InitializePrint(nsString(aTitle), aStartPage, aEndPage);
+  if (NS_FAILED(rv)) {
+    // The parent process will send a 'delete' message to tell this process to
+    // delete our RemotePrintJobChild.  As soon as we return to the event loop
+    // and evaluate that message we will crash if we try to access
+    // mRemotePrintJob.  We must not try to use it again.
+    mRemotePrintJob = nullptr;
+  }
+  return rv;
+}
+
+RefPtr<mozilla::gfx::PrintEndDocumentPromise>
+nsDeviceContextSpecProxy::EndDocument() {
+  if (!mRemotePrintJob || mRemotePrintJob->IsDestroyed()) {
+    mRemotePrintJob = nullptr;
+    return mozilla::gfx::PrintEndDocumentPromise::CreateAndReject(
+        NS_ERROR_NOT_AVAILABLE, __func__);
+  }
+
+  Unused << mRemotePrintJob->SendFinalizePrint();
+
+  if (mRecorder) {
+    MOZ_ASSERT(!mRecorder->IsOpen());
+    mRecorder->DetachResources();
+    mRecorder = nullptr;
+  }
+
+  return mozilla::gfx::PrintEndDocumentPromise::CreateAndResolve(true,
+                                                                 __func__);
+}
+
+NS_IMETHODIMP
+nsDeviceContextSpecProxy::BeginPage(const IntSize& aSizeInPoints) {
+  if (!mRemotePrintJob || mRemotePrintJob->IsDestroyed()) {
+    mRemotePrintJob = nullptr;
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  mRecorder->OpenFD(mRemotePrintJob->GetNextPageFD());
+  mCurrentPageSizeInPoints = aSizeInPoints;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDeviceContextSpecProxy::EndPage() {
+  if (!mRemotePrintJob || mRemotePrintJob->IsDestroyed()) {
+    mRemotePrintJob = nullptr;
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  // Send the page recording to the parent.
+  mRecorder->Close();
+  mRemotePrintJob->ProcessPage(mCurrentPageSizeInPoints,
+                               std::move(mRecorder->TakeDependentSurfaces()));
+
+  return NS_OK;
+}
diff --git a/widget/nsDeviceContextSpecProxy.h b/widget/nsDeviceContextSpecProxy.h
new file mode 100644
index 0000000000..843811c34b
--- /dev/null
+++ b/widget/nsDeviceContextSpecProxy.h
@@ -0,0 +1,59 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsDeviceContextSpecProxy_h
+#define nsDeviceContextSpecProxy_h
+
+#include "nsIDeviceContextSpec.h"
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "mozilla/layout/printing/DrawEventRecorder.h"
+#include "mozilla/gfx/PrintPromise.h"
+
+class nsIFile;
+class nsIUUIDGenerator;
+
+namespace mozilla {
+namespace layout {
+class RemotePrintJobChild;
+}
+}  // namespace mozilla
+
+class nsDeviceContextSpecProxy final : public nsIDeviceContextSpec {
+ public:
+  using IntSize = mozilla::gfx::IntSize;
+  using RemotePrintJobChild = mozilla::layout::RemotePrintJobChild;
+
+  explicit nsDeviceContextSpecProxy(RemotePrintJobChild* aRemotePrintJob);
+
+  NS_DECL_ISUPPORTS
+
+  NS_IMETHOD Init(nsIPrintSettings* aPrintSettings, bool aIsPrintPreview) final;
+
+  already_AddRefed<PrintTarget> MakePrintTarget() final;
+
+  NS_IMETHOD GetDrawEventRecorder(
+      mozilla::gfx::DrawEventRecorder** aDrawEventRecorder) final;
+
+  NS_IMETHOD BeginDocument(const nsAString& aTitle,
+                           const nsAString& aPrintToFileName,
+                           int32_t aStartPage, int32_t aEndPage) final;
+
+  RefPtr<mozilla::gfx::PrintEndDocumentPromise> EndDocument() final;
+
+  NS_IMETHOD BeginPage(const IntSize& aSizeInPoints) final;
+
+  NS_IMETHOD EndPage() final;
+
+ private:
+  ~nsDeviceContextSpecProxy();
+
+  RefPtr<RemotePrintJobChild> mRemotePrintJob;
+  RefPtr<mozilla::layout::DrawEventRecorderPRFileDesc> mRecorder;
+  IntSize mCurrentPageSizeInPoints;
+};
+
+#endif  // nsDeviceContextSpecProxy_h
diff --git a/widget/nsDragServiceProxy.cpp b/widget/nsDragServiceProxy.cpp
new file mode 100644
index 0000000000..cb273a89fa
--- /dev/null
+++ b/widget/nsDragServiceProxy.cpp
@@ -0,0 +1,96 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsDragServiceProxy.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/BrowserChild.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/net/CookieJarSettings.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Unused.h"
+#include "nsContentUtils.h"
+
+using mozilla::CSSIntRegion;
+using mozilla::LayoutDeviceIntRect;
+using mozilla::Maybe;
+using mozilla::Nothing;
+using mozilla::Some;
+using mozilla::dom::BrowserChild;
+using mozilla::gfx::DataSourceSurface;
+using mozilla::gfx::SourceSurface;
+using mozilla::gfx::SurfaceFormat;
+using mozilla::ipc::Shmem;
+
+nsDragServiceProxy::nsDragServiceProxy() = default;
+
+nsDragServiceProxy::~nsDragServiceProxy() = default;
+
+nsresult nsDragServiceProxy::InvokeDragSessionImpl(
+    nsIArray* aArrayTransferables, const Maybe<CSSIntRegion>& aRegion,
+    uint32_t aActionType) {
+  NS_ENSURE_STATE(mSourceDocument->GetDocShell());
+  BrowserChild* child = BrowserChild::GetFrom(mSourceDocument->GetDocShell());
+  NS_ENSURE_STATE(child);
+  nsTArray<mozilla::dom::IPCTransferableData> transferables;
+  nsContentUtils::TransferablesToIPCTransferableDatas(
+      aArrayTransferables, transferables, false, nullptr);
+
+  nsCOMPtr<nsIPrincipal> principal;
+  if (mSourceNode) {
+    principal = mSourceNode->NodePrincipal();
+  }
+
+  nsCOMPtr<nsIContentSecurityPolicy> csp;
+  if (mSourceDocument) {
+    csp = mSourceDocument->GetCsp();
+    // XXX why do we need this here? Shouldn't they be set properly in
+    // nsBaseDragService already?
+    mSourceWindowContext = mSourceDocument->GetWindowContext();
+    mSourceTopWindowContext = mSourceWindowContext
+                                  ? mSourceWindowContext->TopWindowContext()
+                                  : nullptr;
+  }
+
+  nsCOMPtr<nsICookieJarSettings> cookieJarSettings;
+  cookieJarSettings = mSourceDocument->CookieJarSettings();
+  mozilla::net::CookieJarSettingsArgs csArgs;
+  mozilla::net::CookieJarSettings::Cast(cookieJarSettings)->Serialize(csArgs);
+
+  LayoutDeviceIntRect dragRect;
+  if (mHasImage || mSelection) {
+    nsPresContext* pc;
+    RefPtr<SourceSurface> surface;
+    DrawDrag(mSourceNode, aRegion, mScreenPosition, &dragRect, &surface, &pc);
+
+    if (surface) {
+      RefPtr<DataSourceSurface> dataSurface = surface->GetDataSurface();
+      if (dataSurface) {
+        size_t length;
+        int32_t stride;
+        auto surfaceData =
+            nsContentUtils::GetSurfaceData(*dataSurface, &length, &stride);
+        if (surfaceData.isNothing()) {
+          NS_WARNING("Failed to create shared memory for drag session.");
+          return NS_ERROR_FAILURE;
+        }
+
+        mozilla::Unused << child->SendInvokeDragSession(
+            std::move(transferables), aActionType, std::move(surfaceData),
+            stride, dataSurface->GetFormat(), dragRect, principal, csp, csArgs,
+            mSourceWindowContext, mSourceTopWindowContext);
+        StartDragSession();
+        return NS_OK;
+      }
+    }
+  }
+
+  mozilla::Unused << child->SendInvokeDragSession(
+      std::move(transferables), aActionType, Nothing(), 0,
+      static_cast<SurfaceFormat>(0), dragRect, principal, csp, csArgs,
+      mSourceWindowContext, mSourceTopWindowContext);
+  StartDragSession();
+  return NS_OK;
+}
diff --git a/widget/nsDragServiceProxy.h b/widget/nsDragServiceProxy.h
new file mode 100644
index 0000000000..15aa6fa23e
--- /dev/null
+++ b/widget/nsDragServiceProxy.h
@@ -0,0 +1,27 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef NSDRAGSERVICEPROXY_H
+#define NSDRAGSERVICEPROXY_H
+
+#include "nsBaseDragService.h"
+
+class nsDragServiceProxy : public nsBaseDragService {
+ public:
+  nsDragServiceProxy();
+
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(nsDragServiceProxy, nsBaseDragService)
+
+  // nsBaseDragService
+  virtual nsresult InvokeDragSessionImpl(
+      nsIArray* anArrayTransferables,
+      const mozilla::Maybe<mozilla::CSSIntRegion>& aRegion,
+      uint32_t aActionType) override;
+
+ private:
+  virtual ~nsDragServiceProxy();
+};
+
+#endif  // NSDRAGSERVICEPROXY_H
diff --git a/widget/nsFilePickerProxy.cpp b/widget/nsFilePickerProxy.cpp
new file mode 100644
index 0000000000..8777f338cb
--- /dev/null
+++ b/widget/nsFilePickerProxy.cpp
@@ -0,0 +1,296 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsFilePickerProxy.h"
+#include "nsComponentManagerUtils.h"
+#include "nsIFile.h"
+#include "nsSimpleEnumerator.h"
+#include "mozilla/dom/BlobImpl.h"
+#include "mozilla/dom/Directory.h"
+#include "mozilla/dom/File.h"
+#include "mozilla/dom/BrowserChild.h"
+#include "mozilla/dom/BrowsingContext.h"
+#include "mozilla/dom/IPCBlobUtils.h"
+
+using namespace mozilla::dom;
+
+NS_IMPL_ISUPPORTS(nsFilePickerProxy, nsIFilePicker)
+
+nsFilePickerProxy::nsFilePickerProxy()
+    : mSelectedType(0), mCapture(captureNone), mIPCActive(false) {}
+
+nsFilePickerProxy::~nsFilePickerProxy() = default;
+
+NS_IMETHODIMP
+nsFilePickerProxy::Init(mozIDOMWindowProxy* aParent, const nsAString& aTitle,
+                        nsIFilePicker::Mode aMode,
+                        BrowsingContext* aBrowsingContext) {
+  BrowserChild* browserChild = BrowserChild::GetFrom(aParent);
+  if (!browserChild) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mParent = nsPIDOMWindowOuter::From(aParent);
+
+  mMode = aMode;
+
+  browserChild->SendPFilePickerConstructor(this, aTitle, aMode);
+
+  mIPCActive = true;
+  return NS_OK;
+}
+
+void nsFilePickerProxy::InitNative(nsIWidget* aParent,
+                                   const nsAString& aTitle) {}
+
+NS_IMETHODIMP
+nsFilePickerProxy::AppendFilter(const nsAString& aTitle,
+                                const nsAString& aFilter) {
+  mFilterNames.AppendElement(aTitle);
+  mFilters.AppendElement(aFilter);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::GetCapture(nsIFilePicker::CaptureTarget* aCapture) {
+  *aCapture = mCapture;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::SetCapture(nsIFilePicker::CaptureTarget aCapture) {
+  mCapture = aCapture;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::GetDefaultString(nsAString& aDefaultString) {
+  aDefaultString = mDefault;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::SetDefaultString(const nsAString& aDefaultString) {
+  mDefault = aDefaultString;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::GetDefaultExtension(nsAString& aDefaultExtension) {
+  aDefaultExtension = mDefaultExtension;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::SetDefaultExtension(const nsAString& aDefaultExtension) {
+  mDefaultExtension = aDefaultExtension;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::GetFilterIndex(int32_t* aFilterIndex) {
+  *aFilterIndex = mSelectedType;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::SetFilterIndex(int32_t aFilterIndex) {
+  mSelectedType = aFilterIndex;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::GetFile(nsIFile** aFile) {
+  MOZ_ASSERT(false, "GetFile is unimplemented; use GetDomFileOrDirectory");
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::GetFileURL(nsIURI** aFileURL) {
+  MOZ_ASSERT(false, "GetFileURL is unimplemented; use GetDomFileOrDirectory");
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::GetFiles(nsISimpleEnumerator** aFiles) {
+  MOZ_ASSERT(false,
+             "GetFiles is unimplemented; use GetDomFileOrDirectoryEnumerator");
+  return NS_ERROR_FAILURE;
+}
+
+nsresult nsFilePickerProxy::Show(nsIFilePicker::ResultCode* aReturn) {
+  MOZ_ASSERT(false, "Show is unimplemented; use Open");
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::Open(nsIFilePickerShownCallback* aCallback) {
+  mCallback = aCallback;
+
+  nsString displayDirectory;
+  if (mDisplayDirectory) {
+    mDisplayDirectory->GetPath(displayDirectory);
+  }
+
+  if (!mIPCActive) {
+    return NS_ERROR_FAILURE;
+  }
+
+  SendOpen(mSelectedType, mAddToRecentDocs, mDefault, mDefaultExtension,
+           mFilters, mFilterNames, mRawFilters, displayDirectory,
+           mDisplaySpecialDirectory, mOkButtonLabel, mCapture);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::Close() {
+  SendClose();
+
+  return NS_OK;
+}
+
+mozilla::ipc::IPCResult nsFilePickerProxy::Recv__delete__(
+    const MaybeInputData& aData, const nsIFilePicker::ResultCode& aResult) {
+  nsPIDOMWindowInner* inner =
+      mParent ? mParent->GetCurrentInnerWindow() : nullptr;
+
+  if (NS_WARN_IF(!inner)) {
+    return IPC_OK();
+  }
+
+  if (aData.type() == MaybeInputData::TInputBlobs) {
+    const nsTArray<IPCBlob>& blobs = aData.get_InputBlobs().blobs();
+    for (uint32_t i = 0; i < blobs.Length(); ++i) {
+      RefPtr<BlobImpl> blobImpl = IPCBlobUtils::Deserialize(blobs[i]);
+      NS_ENSURE_TRUE(blobImpl, IPC_OK());
+
+      if (!blobImpl->IsFile()) {
+        return IPC_OK();
+      }
+
+      RefPtr<File> file = File::Create(inner->AsGlobal(), blobImpl);
+      if (NS_WARN_IF(!file)) {
+        return IPC_OK();
+      }
+
+      OwningFileOrDirectory* element = mFilesOrDirectories.AppendElement();
+      element->SetAsFile() = file;
+    }
+  } else if (aData.type() == MaybeInputData::TInputDirectory) {
+    nsCOMPtr<nsIFile> file;
+    const nsAString& path(aData.get_InputDirectory().directoryPath());
+    nsresult rv = NS_NewLocalFile(path, true, getter_AddRefs(file));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return IPC_OK();
+    }
+
+    RefPtr<Directory> directory = Directory::Create(inner->AsGlobal(), file);
+    MOZ_ASSERT(directory);
+
+    OwningFileOrDirectory* element = mFilesOrDirectories.AppendElement();
+    element->SetAsDirectory() = directory;
+  }
+
+  if (mCallback) {
+    mCallback->Done(aResult);
+    mCallback = nullptr;
+  }
+
+  return IPC_OK();
+}
+
+NS_IMETHODIMP
+nsFilePickerProxy::GetDomFileOrDirectory(nsISupports** aValue) {
+  *aValue = nullptr;
+  if (mFilesOrDirectories.IsEmpty()) {
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(mFilesOrDirectories.Length() == 1);
+
+  if (mFilesOrDirectories[0].IsFile()) {
+    nsCOMPtr<nsISupports> blob = ToSupports(mFilesOrDirectories[0].GetAsFile());
+    blob.forget(aValue);
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(mFilesOrDirectories[0].IsDirectory());
+  RefPtr<Directory> directory = mFilesOrDirectories[0].GetAsDirectory();
+  directory.forget(aValue);
+  return NS_OK;
+}
+
+namespace {
+
+class SimpleEnumerator final : public nsSimpleEnumerator {
+ public:
+  explicit SimpleEnumerator(
+      const nsTArray<OwningFileOrDirectory>& aFilesOrDirectories)
+      : mFilesOrDirectories(aFilesOrDirectories.Clone()), mIndex(0) {}
+
+  NS_IMETHOD
+  HasMoreElements(bool* aRetvalue) override {
+    MOZ_ASSERT(aRetvalue);
+    *aRetvalue = mIndex < mFilesOrDirectories.Length();
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetNext(nsISupports** aValue) override {
+    NS_ENSURE_TRUE(mIndex < mFilesOrDirectories.Length(), NS_ERROR_FAILURE);
+
+    uint32_t index = mIndex++;
+
+    if (mFilesOrDirectories[index].IsFile()) {
+      nsCOMPtr<nsISupports> blob =
+          ToSupports(mFilesOrDirectories[index].GetAsFile());
+      blob.forget(aValue);
+      return NS_OK;
+    }
+
+    MOZ_ASSERT(mFilesOrDirectories[index].IsDirectory());
+    RefPtr<Directory> directory = mFilesOrDirectories[index].GetAsDirectory();
+    directory.forget(aValue);
+    return NS_OK;
+  }
+
+ private:
+  nsTArray<mozilla::dom::OwningFileOrDirectory> mFilesOrDirectories;
+  uint32_t mIndex;
+};
+
+}  // namespace
+
+NS_IMETHODIMP
+nsFilePickerProxy::GetDomFileOrDirectoryEnumerator(
+    nsISimpleEnumerator** aDomfiles) {
+  RefPtr<SimpleEnumerator> enumerator =
+      new SimpleEnumerator(mFilesOrDirectories);
+  enumerator.forget(aDomfiles);
+  return NS_OK;
+}
+
+void nsFilePickerProxy::ActorDestroy(ActorDestroyReason aWhy) {
+  mIPCActive = false;
+
+  if (mCallback) {
+    mCallback->Done(nsIFilePicker::returnCancel);
+    mCallback = nullptr;
+  }
+}
+
+nsresult nsFilePickerProxy::ResolveSpecialDirectory(
+    const nsAString& aSpecialDirectory) {
+  MOZ_ASSERT(XRE_IsContentProcess());
+  // Resolving the special-directory name to a path in both the child and parent
+  // processes is redundant -- and sandboxing may prevent us from doing so in
+  // the child process, anyway. (See bugs 1357846 and 1838244.)
+  //
+  // Unfortunately we can't easily verify that `aSpecialDirectory` is usable or
+  // even meaningful here, so we just accept anything.
+  return NS_OK;
+}
diff --git a/widget/nsFilePickerProxy.h b/widget/nsFilePickerProxy.h
new file mode 100644
index 0000000000..1b6aef13ed
--- /dev/null
+++ b/widget/nsFilePickerProxy.h
@@ -0,0 +1,89 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef NSFILEPICKERPROXY_H
+#define NSFILEPICKERPROXY_H
+
+#include "nsBaseFilePicker.h"
+#include "nsString.h"
+#include "nsIURI.h"
+#include "nsTArray.h"
+#include "nsCOMArray.h"
+
+#include "mozilla/dom/BrowsingContext.h"
+#include "mozilla/dom/PFilePickerChild.h"
+#include "mozilla/dom/UnionTypes.h"
+
+class nsIWidget;
+class nsIFile;
+class nsPIDOMWindowInner;
+
+/**
+  This class creates a proxy file picker to be used in content processes.
+  The file picker just collects the initialization data and when Show() is
+  called, remotes everything to the chrome process which in turn can show a
+  platform specific file picker.
+*/
+class nsFilePickerProxy : public nsBaseFilePicker,
+                          public mozilla::dom::PFilePickerChild {
+ public:
+  nsFilePickerProxy();
+
+  NS_DECL_ISUPPORTS
+
+  // nsIFilePicker (less what's in nsBaseFilePicker)
+  NS_IMETHOD Init(mozIDOMWindowProxy* aParent, const nsAString& aTitle,
+                  nsIFilePicker::Mode aMode,
+                  mozilla::dom::BrowsingContext* aBrowsingContext) override;
+  NS_IMETHOD AppendFilter(const nsAString& aTitle,
+                          const nsAString& aFilter) override;
+  NS_IMETHOD GetCapture(nsIFilePicker::CaptureTarget* aCapture) override;
+  NS_IMETHOD SetCapture(nsIFilePicker::CaptureTarget aCapture) override;
+  NS_IMETHOD GetDefaultString(nsAString& aDefaultString) override;
+  NS_IMETHOD SetDefaultString(const nsAString& aDefaultString) override;
+  NS_IMETHOD GetDefaultExtension(nsAString& aDefaultExtension) override;
+  NS_IMETHOD SetDefaultExtension(const nsAString& aDefaultExtension) override;
+  NS_IMETHOD GetFilterIndex(int32_t* aFilterIndex) override;
+  NS_IMETHOD SetFilterIndex(int32_t aFilterIndex) override;
+  NS_IMETHOD GetFile(nsIFile** aFile) override;
+  NS_IMETHOD GetFileURL(nsIURI** aFileURL) override;
+  NS_IMETHOD GetFiles(nsISimpleEnumerator** aFiles) override;
+
+  NS_IMETHOD GetDomFileOrDirectory(nsISupports** aValue) override;
+  NS_IMETHOD GetDomFileOrDirectoryEnumerator(
+      nsISimpleEnumerator** aValue) override;
+
+  NS_IMETHOD Open(nsIFilePickerShownCallback* aCallback) override;
+  NS_IMETHOD Close() override;
+
+  // PFilePickerChild
+  virtual mozilla::ipc::IPCResult Recv__delete__(
+      const MaybeInputData& aData,
+      const nsIFilePicker::ResultCode& aResult) override;
+
+ private:
+  ~nsFilePickerProxy();
+  void InitNative(nsIWidget*, const nsAString&) override;
+  nsresult Show(nsIFilePicker::ResultCode* aReturn) override;
+  nsresult ResolveSpecialDirectory(const nsAString& aSpecialDirectory) override;
+
+  void ActorDestroy(ActorDestroyReason aWhy) override;
+
+  nsTArray<mozilla::dom::OwningFileOrDirectory> mFilesOrDirectories;
+  nsCOMPtr<nsIFilePickerShownCallback> mCallback;
+
+  int16_t mSelectedType;
+  nsString mFile;
+  nsString mDefault;
+  nsString mDefaultExtension;
+  nsIFilePicker::CaptureTarget mCapture;
+
+  bool mIPCActive;
+
+  nsTArray<nsString> mFilters;
+  nsTArray<nsString> mFilterNames;
+};
+
+#endif  // NSFILEPICKERPROXY_H
diff --git a/widget/nsGUIEventIPC.h b/widget/nsGUIEventIPC.h
new file mode 100644
index 0000000000..8ba4682935
--- /dev/null
+++ b/widget/nsGUIEventIPC.h
@@ -0,0 +1,1406 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsGUIEventIPC_h__
+#define nsGUIEventIPC_h__
+
+#include "ipc/EnumSerializer.h"
+#include "ipc/IPCMessageUtils.h"
+#include "mozilla/ContentCache.h"
+#include "mozilla/GfxMessageUtils.h"
+#include "mozilla/dom/Touch.h"
+#include "mozilla/ipc/IPDLParamTraits.h"  // for ReadIPDLParam and WriteIPDLParam
+#include "mozilla/ipc/URIUtils.h"         // for IPDLParamTraits<nsIURI*>
+#include "mozilla/layers/LayersMessageUtils.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/TouchEvents.h"
+#include "mozilla/WheelHandlingHelper.h"  // for WheelDeltaAdjustmentStrategy
+#include "mozilla/dom/Selection.h"
+#include "InputData.h"
+
+namespace IPC {
+
+template <>
+struct ParamTraits<mozilla::EventMessage>
+    : public ContiguousEnumSerializer<
+          mozilla::EventMessage, mozilla::EventMessage(0),
+          mozilla::EventMessage::eEventMessage_MaxValue> {};
+
+template <>
+struct ParamTraits<mozilla::BaseEventFlags> {
+  using paramType = mozilla::BaseEventFlags;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    aWriter->WriteBytes(&aParam, sizeof(aParam));
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return aReader->ReadBytesInto(aResult, sizeof(*aResult));
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetEvent> {
+  using paramType = mozilla::WidgetEvent;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    // Mark the event as posted to another process.
+    const_cast<mozilla::WidgetEvent&>(aParam).MarkAsPostedToRemoteProcess();
+
+    WriteParam(aWriter, static_cast<mozilla::EventClassIDType>(aParam.mClass));
+    WriteParam(aWriter, aParam.mMessage);
+    WriteParam(aWriter, aParam.mRefPoint);
+    WriteParam(aWriter, aParam.mFocusSequenceNumber);
+    WriteParam(aWriter, aParam.mTimeStamp);
+    WriteParam(aWriter, aParam.mFlags);
+    WriteParam(aWriter, aParam.mLayersId);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    mozilla::EventClassIDType eventClassID = 0;
+    bool ret = ReadParam(aReader, &eventClassID) &&
+               ReadParam(aReader, &aResult->mMessage) &&
+               ReadParam(aReader, &aResult->mRefPoint) &&
+               ReadParam(aReader, &aResult->mFocusSequenceNumber) &&
+               ReadParam(aReader, &aResult->mTimeStamp) &&
+               ReadParam(aReader, &aResult->mFlags) &&
+               ReadParam(aReader, &aResult->mLayersId);
+    aResult->mClass = static_cast<mozilla::EventClassID>(eventClassID);
+    if (ret) {
+      // Reset cross process dispatching state here because the event has not
+      // been dispatched to different process from current process.
+      aResult->ResetCrossProcessDispatchingState();
+      // Mark the event comes from another process.
+      aResult->MarkAsComingFromAnotherProcess();
+    }
+    return ret;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetGUIEvent> {
+  using paramType = mozilla::WidgetGUIEvent;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::WidgetEvent&>(aParam));
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, static_cast<mozilla::WidgetEvent*>(aResult));
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetInputEvent> {
+  using paramType = mozilla::WidgetInputEvent;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::WidgetGUIEvent&>(aParam));
+    WriteParam(aWriter, aParam.mModifiers);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, static_cast<mozilla::WidgetGUIEvent*>(aResult)) &&
+           ReadParam(aReader, &aResult->mModifiers);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetMouseEventBase> {
+  using paramType = mozilla::WidgetMouseEventBase;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::WidgetInputEvent&>(aParam));
+    WriteParam(aWriter, aParam.mButton);
+    WriteParam(aWriter, aParam.mButtons);
+    WriteParam(aWriter, aParam.mPressure);
+    WriteParam(aWriter, aParam.mInputSource);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader,
+                     static_cast<mozilla::WidgetInputEvent*>(aResult)) &&
+           ReadParam(aReader, &aResult->mButton) &&
+           ReadParam(aReader, &aResult->mButtons) &&
+           ReadParam(aReader, &aResult->mPressure) &&
+           ReadParam(aReader, &aResult->mInputSource);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetWheelEvent> {
+  using paramType = mozilla::WidgetWheelEvent;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter,
+               static_cast<const mozilla::WidgetMouseEventBase&>(aParam));
+    WriteParam(aWriter, aParam.mDeltaX);
+    WriteParam(aWriter, aParam.mDeltaY);
+    WriteParam(aWriter, aParam.mDeltaZ);
+    WriteParam(aWriter, aParam.mDeltaMode);
+    WriteParam(aWriter, aParam.mWheelTicksX);
+    WriteParam(aWriter, aParam.mWheelTicksY);
+    WriteParam(aWriter, aParam.mCustomizedByUserPrefs);
+    WriteParam(aWriter, aParam.mMayHaveMomentum);
+    WriteParam(aWriter, aParam.mIsMomentum);
+    WriteParam(aWriter, aParam.mIsNoLineOrPageDelta);
+    WriteParam(aWriter, aParam.mLineOrPageDeltaX);
+    WriteParam(aWriter, aParam.mLineOrPageDeltaY);
+    WriteParam(aWriter, static_cast<uint8_t>(aParam.mScrollType));
+    WriteParam(aWriter, aParam.mOverflowDeltaX);
+    WriteParam(aWriter, aParam.mOverflowDeltaY);
+    WriteParam(aWriter, aParam.mViewPortIsOverscrolled);
+    WriteParam(aWriter, aParam.mCanTriggerSwipe);
+    WriteParam(aWriter, aParam.mAllowToOverrideSystemScrollSpeed);
+    WriteParam(aWriter, aParam.mDeltaValuesHorizontalizedForDefaultHandler);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    uint8_t scrollType = 0;
+    bool rv = ReadParam(aReader,
+                        static_cast<mozilla::WidgetMouseEventBase*>(aResult)) &&
+              ReadParam(aReader, &aResult->mDeltaX) &&
+              ReadParam(aReader, &aResult->mDeltaY) &&
+              ReadParam(aReader, &aResult->mDeltaZ) &&
+              ReadParam(aReader, &aResult->mDeltaMode) &&
+              ReadParam(aReader, &aResult->mWheelTicksX) &&
+              ReadParam(aReader, &aResult->mWheelTicksY) &&
+              ReadParam(aReader, &aResult->mCustomizedByUserPrefs) &&
+              ReadParam(aReader, &aResult->mMayHaveMomentum) &&
+              ReadParam(aReader, &aResult->mIsMomentum) &&
+              ReadParam(aReader, &aResult->mIsNoLineOrPageDelta) &&
+              ReadParam(aReader, &aResult->mLineOrPageDeltaX) &&
+              ReadParam(aReader, &aResult->mLineOrPageDeltaY) &&
+              ReadParam(aReader, &scrollType) &&
+              ReadParam(aReader, &aResult->mOverflowDeltaX) &&
+              ReadParam(aReader, &aResult->mOverflowDeltaY) &&
+              ReadParam(aReader, &aResult->mViewPortIsOverscrolled) &&
+              ReadParam(aReader, &aResult->mCanTriggerSwipe) &&
+              ReadParam(aReader, &aResult->mAllowToOverrideSystemScrollSpeed) &&
+              ReadParam(aReader,
+                        &aResult->mDeltaValuesHorizontalizedForDefaultHandler);
+    aResult->mScrollType =
+        static_cast<mozilla::WidgetWheelEvent::ScrollType>(scrollType);
+    return rv;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetPointerHelper> {
+  using paramType = mozilla::WidgetPointerHelper;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.pointerId);
+    WriteParam(aWriter, aParam.tiltX);
+    WriteParam(aWriter, aParam.tiltY);
+    WriteParam(aWriter, aParam.twist);
+    WriteParam(aWriter, aParam.tangentialPressure);
+    // We don't serialize convertToPointer since it's temporarily variable and
+    // should be reset to default.
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    bool rv;
+    rv = ReadParam(aReader, &aResult->pointerId) &&
+         ReadParam(aReader, &aResult->tiltX) &&
+         ReadParam(aReader, &aResult->tiltY) &&
+         ReadParam(aReader, &aResult->twist) &&
+         ReadParam(aReader, &aResult->tangentialPressure);
+    return rv;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetMouseEvent> {
+  using paramType = mozilla::WidgetMouseEvent;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter,
+               static_cast<const mozilla::WidgetMouseEventBase&>(aParam));
+    WriteParam(aWriter,
+               static_cast<const mozilla::WidgetPointerHelper&>(aParam));
+    WriteParam(aWriter, aParam.mIgnoreRootScrollFrame);
+    WriteParam(aWriter, aParam.mClickEventPrevented);
+    WriteParam(aWriter, static_cast<paramType::ReasonType>(aParam.mReason));
+    WriteParam(aWriter, static_cast<paramType::ContextMenuTriggerType>(
+                            aParam.mContextMenuTrigger));
+    WriteParam(aWriter, aParam.mExitFrom.isSome());
+    if (aParam.mExitFrom.isSome()) {
+      WriteParam(aWriter, static_cast<paramType::ExitFromType>(
+                              aParam.mExitFrom.value()));
+    }
+    WriteParam(aWriter, aParam.mClickCount);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    bool rv;
+    paramType::ReasonType reason = 0;
+    paramType::ContextMenuTriggerType contextMenuTrigger = 0;
+    bool hasExitFrom = false;
+    rv = ReadParam(aReader,
+                   static_cast<mozilla::WidgetMouseEventBase*>(aResult)) &&
+         ReadParam(aReader,
+                   static_cast<mozilla::WidgetPointerHelper*>(aResult)) &&
+         ReadParam(aReader, &aResult->mIgnoreRootScrollFrame) &&
+         ReadParam(aReader, &aResult->mClickEventPrevented) &&
+         ReadParam(aReader, &reason) && ReadParam(aReader, &contextMenuTrigger);
+    aResult->mReason = static_cast<paramType::Reason>(reason);
+    aResult->mContextMenuTrigger =
+        static_cast<paramType::ContextMenuTrigger>(contextMenuTrigger);
+    rv = rv && ReadParam(aReader, &hasExitFrom);
+    if (hasExitFrom) {
+      paramType::ExitFromType exitFrom = 0;
+      rv = rv && ReadParam(aReader, &exitFrom);
+      aResult->mExitFrom = Some(static_cast<paramType::ExitFrom>(exitFrom));
+    }
+    rv = rv && ReadParam(aReader, &aResult->mClickCount);
+    return rv;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetDragEvent> {
+  using paramType = mozilla::WidgetDragEvent;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::WidgetMouseEvent&>(aParam));
+    WriteParam(aWriter, aParam.mUserCancelled);
+    WriteParam(aWriter, aParam.mDefaultPreventedOnContent);
+    WriteParam(aWriter, aParam.mInHTMLEditorEventListener);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    bool rv =
+        ReadParam(aReader, static_cast<mozilla::WidgetMouseEvent*>(aResult)) &&
+        ReadParam(aReader, &aResult->mUserCancelled) &&
+        ReadParam(aReader, &aResult->mDefaultPreventedOnContent) &&
+        ReadParam(aReader, &aResult->mInHTMLEditorEventListener);
+    return rv;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetPointerEvent> {
+  using paramType = mozilla::WidgetPointerEvent;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::WidgetMouseEvent&>(aParam));
+    WriteParam(aWriter, aParam.mWidth);
+    WriteParam(aWriter, aParam.mHeight);
+    WriteParam(aWriter, aParam.mIsPrimary);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    bool rv =
+        ReadParam(aReader, static_cast<mozilla::WidgetMouseEvent*>(aResult)) &&
+        ReadParam(aReader, &aResult->mWidth) &&
+        ReadParam(aReader, &aResult->mHeight) &&
+        ReadParam(aReader, &aResult->mIsPrimary);
+    return rv;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetTouchEvent> {
+  using paramType = mozilla::WidgetTouchEvent;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::WidgetInputEvent&>(aParam));
+    WriteParam(aWriter, aParam.mInputSource);
+    WriteParam(aWriter, aParam.mButton);
+    WriteParam(aWriter, aParam.mButtons);
+    // Sigh, Touch bites us again!  We want to be able to do
+    //   WriteParam(aWriter, aParam.mTouches);
+    const paramType::TouchArray& touches = aParam.mTouches;
+    WriteParam(aWriter, touches.Length());
+    for (uint32_t i = 0; i < touches.Length(); ++i) {
+      mozilla::dom::Touch* touch = touches[i];
+      WriteParam(aWriter, touch->mIdentifier);
+      WriteParam(aWriter, touch->mRefPoint);
+      WriteParam(aWriter, touch->mRadius);
+      WriteParam(aWriter, touch->mRotationAngle);
+      WriteParam(aWriter, touch->mForce);
+      WriteParam(aWriter, touch->tiltX);
+      WriteParam(aWriter, touch->tiltY);
+      WriteParam(aWriter, touch->twist);
+    }
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    paramType::TouchArray::size_type numTouches;
+    if (!ReadParam(aReader, static_cast<mozilla::WidgetInputEvent*>(aResult)) ||
+        !ReadParam(aReader, &aResult->mInputSource) ||
+        !ReadParam(aReader, &aResult->mButton) ||
+        !ReadParam(aReader, &aResult->mButtons) ||
+        !ReadParam(aReader, &numTouches)) {
+      return false;
+    }
+    for (uint32_t i = 0; i < numTouches; ++i) {
+      int32_t identifier;
+      mozilla::LayoutDeviceIntPoint refPoint;
+      mozilla::LayoutDeviceIntPoint radius;
+      float rotationAngle;
+      float force;
+      uint32_t tiltX;
+      uint32_t tiltY;
+      uint32_t twist;
+      if (!ReadParam(aReader, &identifier) || !ReadParam(aReader, &refPoint) ||
+          !ReadParam(aReader, &radius) || !ReadParam(aReader, &rotationAngle) ||
+          !ReadParam(aReader, &force) || !ReadParam(aReader, &tiltX) ||
+          !ReadParam(aReader, &tiltY) || !ReadParam(aReader, &twist)) {
+        return false;
+      }
+      auto* touch = new mozilla::dom::Touch(identifier, refPoint, radius,
+                                            rotationAngle, force);
+      touch->tiltX = tiltX;
+      touch->tiltY = tiltY;
+      touch->twist = twist;
+      aResult->mTouches.AppendElement(touch);
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::AlternativeCharCode> {
+  using paramType = mozilla::AlternativeCharCode;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mUnshiftedCharCode);
+    WriteParam(aWriter, aParam.mShiftedCharCode);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mUnshiftedCharCode) &&
+           ReadParam(aReader, &aResult->mShiftedCharCode);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::ShortcutKeyCandidate::ShiftState>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::ShortcutKeyCandidate::ShiftState,
+          mozilla::ShortcutKeyCandidate::ShiftState::Ignorable,
+          mozilla::ShortcutKeyCandidate::ShiftState::MatchExactly> {};
+
+template <>
+struct ParamTraits<mozilla::ShortcutKeyCandidate::SkipIfEarlierHandlerDisabled>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::ShortcutKeyCandidate::SkipIfEarlierHandlerDisabled,
+          mozilla::ShortcutKeyCandidate::SkipIfEarlierHandlerDisabled::No,
+          mozilla::ShortcutKeyCandidate::SkipIfEarlierHandlerDisabled::Yes> {};
+
+template <>
+struct ParamTraits<mozilla::ShortcutKeyCandidate> {
+  using paramType = mozilla::ShortcutKeyCandidate;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mCharCode);
+    WriteParam(aWriter, aParam.mShiftState);
+    WriteParam(aWriter, aParam.mSkipIfEarlierHandlerDisabled);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mCharCode) &&
+           ReadParam(aReader, &aResult->mShiftState) &&
+           ReadParam(aReader, &aResult->mSkipIfEarlierHandlerDisabled);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetKeyboardEvent> {
+  using paramType = mozilla::WidgetKeyboardEvent;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::WidgetInputEvent&>(aParam));
+    WriteParam(aWriter,
+               static_cast<mozilla::KeyNameIndexType>(aParam.mKeyNameIndex));
+    WriteParam(aWriter,
+               static_cast<mozilla::CodeNameIndexType>(aParam.mCodeNameIndex));
+    WriteParam(aWriter, aParam.mKeyValue);
+    WriteParam(aWriter, aParam.mCodeValue);
+    WriteParam(aWriter, aParam.mKeyCode);
+    WriteParam(aWriter, aParam.mCharCode);
+    WriteParam(aWriter, aParam.mPseudoCharCode);
+    WriteParam(aWriter, aParam.mAlternativeCharCodes);
+    WriteParam(aWriter, aParam.mIsRepeat);
+    WriteParam(aWriter, aParam.mLocation);
+    WriteParam(aWriter, aParam.mUniqueId);
+    WriteParam(aWriter, aParam.mIsSynthesizedByTIP);
+    WriteParam(aWriter, aParam.mMaybeSkippableInRemoteProcess);
+
+    // An OS-specific native event might be attached in |mNativeKeyEvent|,  but
+    // that cannot be copied across process boundaries.
+
+    WriteParam(aWriter, aParam.mEditCommandsForSingleLineEditor);
+    WriteParam(aWriter, aParam.mEditCommandsForMultiLineEditor);
+    WriteParam(aWriter, aParam.mEditCommandsForRichTextEditor);
+    WriteParam(aWriter, aParam.mEditCommandsForSingleLineEditorInitialized);
+    WriteParam(aWriter, aParam.mEditCommandsForMultiLineEditorInitialized);
+    WriteParam(aWriter, aParam.mEditCommandsForRichTextEditorInitialized);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    mozilla::KeyNameIndexType keyNameIndex = 0;
+    mozilla::CodeNameIndexType codeNameIndex = 0;
+    if (ReadParam(aReader, static_cast<mozilla::WidgetInputEvent*>(aResult)) &&
+        ReadParam(aReader, &keyNameIndex) &&
+        ReadParam(aReader, &codeNameIndex) &&
+        ReadParam(aReader, &aResult->mKeyValue) &&
+        ReadParam(aReader, &aResult->mCodeValue) &&
+        ReadParam(aReader, &aResult->mKeyCode) &&
+        ReadParam(aReader, &aResult->mCharCode) &&
+        ReadParam(aReader, &aResult->mPseudoCharCode) &&
+        ReadParam(aReader, &aResult->mAlternativeCharCodes) &&
+        ReadParam(aReader, &aResult->mIsRepeat) &&
+        ReadParam(aReader, &aResult->mLocation) &&
+        ReadParam(aReader, &aResult->mUniqueId) &&
+        ReadParam(aReader, &aResult->mIsSynthesizedByTIP) &&
+        ReadParam(aReader, &aResult->mMaybeSkippableInRemoteProcess) &&
+        ReadParam(aReader, &aResult->mEditCommandsForSingleLineEditor) &&
+        ReadParam(aReader, &aResult->mEditCommandsForMultiLineEditor) &&
+        ReadParam(aReader, &aResult->mEditCommandsForRichTextEditor) &&
+        ReadParam(aReader,
+                  &aResult->mEditCommandsForSingleLineEditorInitialized) &&
+        ReadParam(aReader,
+                  &aResult->mEditCommandsForMultiLineEditorInitialized) &&
+        ReadParam(aReader,
+                  &aResult->mEditCommandsForRichTextEditorInitialized)) {
+      aResult->mKeyNameIndex = static_cast<mozilla::KeyNameIndex>(keyNameIndex);
+      aResult->mCodeNameIndex =
+          static_cast<mozilla::CodeNameIndex>(codeNameIndex);
+      aResult->mNativeKeyEvent = nullptr;
+      return true;
+    }
+    return false;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::TextRangeStyle> {
+  using paramType = mozilla::TextRangeStyle;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mDefinedStyles);
+    WriteParam(aWriter, static_cast<mozilla::TextRangeStyle::LineStyleType>(
+                            aParam.mLineStyle));
+    WriteParam(aWriter, aParam.mIsBoldLine);
+    WriteParam(aWriter, aParam.mForegroundColor);
+    WriteParam(aWriter, aParam.mBackgroundColor);
+    WriteParam(aWriter, aParam.mUnderlineColor);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    mozilla::TextRangeStyle::LineStyleType lineStyle;
+    if (!ReadParam(aReader, &aResult->mDefinedStyles) ||
+        !ReadParam(aReader, &lineStyle) ||
+        !ReadParam(aReader, &aResult->mIsBoldLine) ||
+        !ReadParam(aReader, &aResult->mForegroundColor) ||
+        !ReadParam(aReader, &aResult->mBackgroundColor) ||
+        !ReadParam(aReader, &aResult->mUnderlineColor)) {
+      return false;
+    }
+    aResult->mLineStyle = mozilla::TextRangeStyle::ToLineStyle(lineStyle);
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::TextRange> {
+  using paramType = mozilla::TextRange;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mStartOffset);
+    WriteParam(aWriter, aParam.mEndOffset);
+    WriteParam(aWriter, mozilla::ToRawTextRangeType(aParam.mRangeType));
+    WriteParam(aWriter, aParam.mRangeStyle);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    mozilla::RawTextRangeType rawTextRangeType;
+    if (ReadParam(aReader, &aResult->mStartOffset) &&
+        ReadParam(aReader, &aResult->mEndOffset) &&
+        ReadParam(aReader, &rawTextRangeType) &&
+        ReadParam(aReader, &aResult->mRangeStyle)) {
+      aResult->mRangeType = mozilla::ToTextRangeType(rawTextRangeType);
+      return true;
+    }
+    return false;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::TextRangeArray> {
+  using paramType = mozilla::TextRangeArray;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.Length());
+    for (uint32_t index = 0; index < aParam.Length(); index++) {
+      WriteParam(aWriter, aParam[index]);
+    }
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    paramType::size_type length;
+    if (!ReadParam(aReader, &length)) {
+      return false;
+    }
+    for (uint32_t index = 0; index < length; index++) {
+      mozilla::TextRange textRange;
+      if (!ReadParam(aReader, &textRange)) {
+        aResult->Clear();
+        return false;
+      }
+      aResult->AppendElement(textRange);
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetCompositionEvent> {
+  using paramType = mozilla::WidgetCompositionEvent;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::WidgetGUIEvent&>(aParam));
+    WriteParam(aWriter, aParam.mData);
+    WriteParam(aWriter, aParam.mNativeIMEContext);
+    WriteParam(aWriter, aParam.mCompositionId);
+    bool hasRanges = !!aParam.mRanges;
+    WriteParam(aWriter, hasRanges);
+    if (hasRanges) {
+      WriteParam(aWriter, *aParam.mRanges.get());
+    }
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    bool hasRanges;
+    if (!ReadParam(aReader, static_cast<mozilla::WidgetGUIEvent*>(aResult)) ||
+        !ReadParam(aReader, &aResult->mData) ||
+        !ReadParam(aReader, &aResult->mNativeIMEContext) ||
+        !ReadParam(aReader, &aResult->mCompositionId) ||
+        !ReadParam(aReader, &hasRanges)) {
+      return false;
+    }
+
+    if (!hasRanges) {
+      aResult->mRanges = nullptr;
+    } else {
+      aResult->mRanges = new mozilla::TextRangeArray();
+      if (!ReadParam(aReader, aResult->mRanges.get())) {
+        return false;
+      }
+    }
+    return true;
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::FontRange> {
+  using paramType = mozilla::FontRange;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mStartOffset);
+    WriteParam(aWriter, aParam.mFontName);
+    WriteParam(aWriter, aParam.mFontSize);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mStartOffset) &&
+           ReadParam(aReader, &aResult->mFontName) &&
+           ReadParam(aReader, &aResult->mFontSize);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WidgetSelectionEvent> {
+  using paramType = mozilla::WidgetSelectionEvent;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::WidgetGUIEvent&>(aParam));
+    WriteParam(aWriter, aParam.mOffset);
+    WriteParam(aWriter, aParam.mLength);
+    WriteParam(aWriter, aParam.mReversed);
+    WriteParam(aWriter, aParam.mExpandToClusterBoundary);
+    WriteParam(aWriter, aParam.mSucceeded);
+    WriteParam(aWriter, aParam.mUseNativeLineBreak);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, static_cast<mozilla::WidgetGUIEvent*>(aResult)) &&
+           ReadParam(aReader, &aResult->mOffset) &&
+           ReadParam(aReader, &aResult->mLength) &&
+           ReadParam(aReader, &aResult->mReversed) &&
+           ReadParam(aReader, &aResult->mExpandToClusterBoundary) &&
+           ReadParam(aReader, &aResult->mSucceeded) &&
+           ReadParam(aReader, &aResult->mUseNativeLineBreak);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::widget::IMENotificationRequests> {
+  using paramType = mozilla::widget::IMENotificationRequests;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mWantUpdates);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mWantUpdates);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::widget::NativeIMEContext> {
+  using paramType = mozilla::widget::NativeIMEContext;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mRawNativeIMEContext);
+    WriteParam(aWriter, aParam.mOriginProcessID);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mRawNativeIMEContext) &&
+           ReadParam(aReader, &aResult->mOriginProcessID);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::widget::IMENotification::SelectionChangeDataBase> {
+  using paramType = mozilla::widget::IMENotification::SelectionChangeDataBase;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    MOZ_RELEASE_ASSERT(aParam.mString);
+    WriteParam(aWriter, aParam.mOffset);
+    WriteParam(aWriter, *aParam.mString);
+    WriteParam(aWriter, aParam.mWritingModeBits);
+    WriteParam(aWriter, aParam.mIsInitialized);
+    WriteParam(aWriter, aParam.mHasRange);
+    WriteParam(aWriter, aParam.mReversed);
+    WriteParam(aWriter, aParam.mCausedByComposition);
+    WriteParam(aWriter, aParam.mCausedBySelectionEvent);
+    WriteParam(aWriter, aParam.mOccurredDuringComposition);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    aResult->mString = new nsString();
+    return ReadParam(aReader, &aResult->mOffset) &&
+           ReadParam(aReader, aResult->mString) &&
+           ReadParam(aReader, &aResult->mWritingModeBits) &&
+           ReadParam(aReader, &aResult->mIsInitialized) &&
+           ReadParam(aReader, &aResult->mHasRange) &&
+           ReadParam(aReader, &aResult->mReversed) &&
+           ReadParam(aReader, &aResult->mCausedByComposition) &&
+           ReadParam(aReader, &aResult->mCausedBySelectionEvent) &&
+           ReadParam(aReader, &aResult->mOccurredDuringComposition);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::widget::IMENotification::TextChangeDataBase> {
+  using paramType = mozilla::widget::IMENotification::TextChangeDataBase;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mStartOffset);
+    WriteParam(aWriter, aParam.mRemovedEndOffset);
+    WriteParam(aWriter, aParam.mAddedEndOffset);
+    WriteParam(aWriter, aParam.mCausedOnlyByComposition);
+    WriteParam(aWriter, aParam.mIncludingChangesDuringComposition);
+    WriteParam(aWriter, aParam.mIncludingChangesWithoutComposition);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mStartOffset) &&
+           ReadParam(aReader, &aResult->mRemovedEndOffset) &&
+           ReadParam(aReader, &aResult->mAddedEndOffset) &&
+           ReadParam(aReader, &aResult->mCausedOnlyByComposition) &&
+           ReadParam(aReader, &aResult->mIncludingChangesDuringComposition) &&
+           ReadParam(aReader, &aResult->mIncludingChangesWithoutComposition);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::widget::IMENotification::MouseButtonEventData> {
+  using paramType = mozilla::widget::IMENotification::MouseButtonEventData;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mEventMessage);
+    WriteParam(aWriter, aParam.mOffset);
+    WriteParam(aWriter, aParam.mCursorPos);
+    WriteParam(aWriter, aParam.mCharRect);
+    WriteParam(aWriter, aParam.mButton);
+    WriteParam(aWriter, aParam.mButtons);
+    WriteParam(aWriter, aParam.mModifiers);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mEventMessage) &&
+           ReadParam(aReader, &aResult->mOffset) &&
+           ReadParam(aReader, &aResult->mCursorPos) &&
+           ReadParam(aReader, &aResult->mCharRect) &&
+           ReadParam(aReader, &aResult->mButton) &&
+           ReadParam(aReader, &aResult->mButtons) &&
+           ReadParam(aReader, &aResult->mModifiers);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::widget::IMENotification> {
+  using paramType = mozilla::widget::IMENotification;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter,
+               static_cast<mozilla::widget::IMEMessageType>(aParam.mMessage));
+    switch (aParam.mMessage) {
+      case mozilla::widget::NOTIFY_IME_OF_SELECTION_CHANGE:
+        WriteParam(aWriter, aParam.mSelectionChangeData);
+        return;
+      case mozilla::widget::NOTIFY_IME_OF_TEXT_CHANGE:
+        WriteParam(aWriter, aParam.mTextChangeData);
+        return;
+      case mozilla::widget::NOTIFY_IME_OF_MOUSE_BUTTON_EVENT:
+        WriteParam(aWriter, aParam.mMouseButtonEventData);
+        return;
+      default:
+        return;
+    }
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    mozilla::widget::IMEMessageType IMEMessage = 0;
+    if (!ReadParam(aReader, &IMEMessage)) {
+      return false;
+    }
+    aResult->mMessage = static_cast<mozilla::widget::IMEMessage>(IMEMessage);
+    switch (aResult->mMessage) {
+      case mozilla::widget::NOTIFY_IME_OF_SELECTION_CHANGE:
+        return ReadParam(aReader, &aResult->mSelectionChangeData);
+      case mozilla::widget::NOTIFY_IME_OF_TEXT_CHANGE:
+        return ReadParam(aReader, &aResult->mTextChangeData);
+      case mozilla::widget::NOTIFY_IME_OF_MOUSE_BUTTON_EVENT:
+        return ReadParam(aReader, &aResult->mMouseButtonEventData);
+      default:
+        return true;
+    }
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::widget::IMEEnabled>
+    : ContiguousEnumSerializer<mozilla::widget::IMEEnabled,
+                               mozilla::widget::IMEEnabled::Disabled,
+                               mozilla::widget::IMEEnabled::Unknown> {};
+
+template <>
+struct ParamTraits<mozilla::widget::IMEState::Open>
+    : ContiguousEnumSerializerInclusive<
+          mozilla::widget::IMEState::Open,
+          mozilla::widget::IMEState::Open::OPEN_STATE_NOT_SUPPORTED,
+          mozilla::widget::IMEState::Open::CLOSED> {};
+
+template <>
+struct ParamTraits<mozilla::widget::IMEState> {
+  using paramType = mozilla::widget::IMEState;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mEnabled);
+    WriteParam(aWriter, aParam.mOpen);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mEnabled) &&
+           ReadParam(aReader, &aResult->mOpen);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::widget::InputContext::Origin>
+    : ContiguousEnumSerializerInclusive<
+          mozilla::widget::InputContext::Origin,
+          mozilla::widget::InputContext::Origin::ORIGIN_MAIN,
+          mozilla::widget::InputContext::Origin::ORIGIN_CONTENT> {};
+
+template <>
+struct ParamTraits<mozilla::widget::InputContext> {
+  using paramType = mozilla::widget::InputContext;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mIMEState);
+    WriteParam(aWriter, aParam.mHTMLInputType);
+    WriteParam(aWriter, aParam.mHTMLInputMode);
+    WriteParam(aWriter, aParam.mActionHint);
+    WriteParam(aWriter, aParam.mAutocapitalize);
+    WriteParam(aWriter, aParam.mOrigin);
+    WriteParam(aWriter, aParam.mHasHandledUserInput);
+    WriteParam(aWriter, aParam.mInPrivateBrowsing);
+    mozilla::ipc::WriteIPDLParam(aWriter, aWriter->GetActor(), aParam.mURI);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mIMEState) &&
+           ReadParam(aReader, &aResult->mHTMLInputType) &&
+           ReadParam(aReader, &aResult->mHTMLInputMode) &&
+           ReadParam(aReader, &aResult->mActionHint) &&
+           ReadParam(aReader, &aResult->mAutocapitalize) &&
+           ReadParam(aReader, &aResult->mOrigin) &&
+           ReadParam(aReader, &aResult->mHasHandledUserInput) &&
+           ReadParam(aReader, &aResult->mInPrivateBrowsing) &&
+           mozilla::ipc::ReadIPDLParam(aReader, aReader->GetActor(),
+                                       address_of(aResult->mURI));
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::widget::InputContextAction::Cause>
+    : ContiguousEnumSerializerInclusive<
+          mozilla::widget::InputContextAction::Cause,
+          mozilla::widget::InputContextAction::Cause::CAUSE_UNKNOWN,
+          mozilla::widget::InputContextAction::Cause::
+              CAUSE_UNKNOWN_DURING_KEYBOARD_INPUT> {};
+
+template <>
+struct ParamTraits<mozilla::widget::InputContextAction::FocusChange>
+    : ContiguousEnumSerializerInclusive<
+          mozilla::widget::InputContextAction::FocusChange,
+          mozilla::widget::InputContextAction::FocusChange::FOCUS_NOT_CHANGED,
+          mozilla::widget::InputContextAction::FocusChange::WIDGET_CREATED> {};
+
+template <>
+struct ParamTraits<mozilla::widget::InputContextAction> {
+  using paramType = mozilla::widget::InputContextAction;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mCause);
+    WriteParam(aWriter, aParam.mFocusChange);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mCause) &&
+           ReadParam(aReader, &aResult->mFocusChange);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::WritingMode> {
+  using paramType = mozilla::WritingMode;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mWritingMode._0);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mWritingMode._0);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::ContentCache::Selection> {
+  using paramType = mozilla::ContentCache::Selection;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mAnchor);
+    WriteParam(aWriter, aParam.mFocus);
+    WriteParam(aWriter, aParam.mWritingMode);
+    WriteParam(aWriter, aParam.mHasRange);
+    WriteParam(aWriter, aParam.mAnchorCharRects[0]);
+    WriteParam(aWriter, aParam.mAnchorCharRects[1]);
+    WriteParam(aWriter, aParam.mFocusCharRects[0]);
+    WriteParam(aWriter, aParam.mFocusCharRects[1]);
+    WriteParam(aWriter, aParam.mRect);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mAnchor) &&
+           ReadParam(aReader, &aResult->mFocus) &&
+           ReadParam(aReader, &aResult->mWritingMode) &&
+           ReadParam(aReader, &aResult->mHasRange) &&
+           ReadParam(aReader, &aResult->mAnchorCharRects[0]) &&
+           ReadParam(aReader, &aResult->mAnchorCharRects[1]) &&
+           ReadParam(aReader, &aResult->mFocusCharRects[0]) &&
+           ReadParam(aReader, &aResult->mFocusCharRects[1]) &&
+           ReadParam(aReader, &aResult->mRect);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::ContentCache::Caret> {
+  using paramType = mozilla::ContentCache::Caret;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mOffset);
+    WriteParam(aWriter, aParam.mRect);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mOffset) &&
+           ReadParam(aReader, &aResult->mRect);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::ContentCache::TextRectArray> {
+  using paramType = mozilla::ContentCache::TextRectArray;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mStart);
+    WriteParam(aWriter, aParam.mRects);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mStart) &&
+           ReadParam(aReader, &aResult->mRects);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::ContentCache> {
+  using paramType = mozilla::ContentCache;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mCompositionStart);
+    WriteParam(aWriter, aParam.mText);
+    WriteParam(aWriter, aParam.mSelection);
+    WriteParam(aWriter, aParam.mFirstCharRect);
+    WriteParam(aWriter, aParam.mCaret);
+    WriteParam(aWriter, aParam.mTextRectArray);
+    WriteParam(aWriter, aParam.mLastCommitStringTextRectArray);
+    WriteParam(aWriter, aParam.mEditorRect);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mCompositionStart) &&
+           ReadParam(aReader, &aResult->mText) &&
+           ReadParam(aReader, &aResult->mSelection) &&
+           ReadParam(aReader, &aResult->mFirstCharRect) &&
+           ReadParam(aReader, &aResult->mCaret) &&
+           ReadParam(aReader, &aResult->mTextRectArray) &&
+           ReadParam(aReader, &aResult->mLastCommitStringTextRectArray) &&
+           ReadParam(aReader, &aResult->mEditorRect);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::widget::CandidateWindowPosition> {
+  using paramType = mozilla::widget::CandidateWindowPosition;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mPoint);
+    WriteParam(aWriter, aParam.mRect);
+    WriteParam(aWriter, aParam.mExcludeRect);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mPoint) &&
+           ReadParam(aReader, &aResult->mRect) &&
+           ReadParam(aReader, &aResult->mExcludeRect);
+  }
+};
+
+// InputData.h
+
+template <>
+struct ParamTraits<mozilla::InputType>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::InputType, mozilla::InputType::MULTITOUCH_INPUT,
+          mozilla::kHighestInputType> {};
+
+template <>
+struct ParamTraits<mozilla::InputData> {
+  using paramType = mozilla::InputData;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mInputType);
+    WriteParam(aWriter, aParam.mTimeStamp);
+    WriteParam(aWriter, aParam.modifiers);
+    WriteParam(aWriter, aParam.mFocusSequenceNumber);
+    WriteParam(aWriter, aParam.mLayersId);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, &aResult->mInputType) &&
+           ReadParam(aReader, &aResult->mTimeStamp) &&
+           ReadParam(aReader, &aResult->modifiers) &&
+           ReadParam(aReader, &aResult->mFocusSequenceNumber) &&
+           ReadParam(aReader, &aResult->mLayersId);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::SingleTouchData::HistoricalTouchData> {
+  using paramType = mozilla::SingleTouchData::HistoricalTouchData;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mTimeStamp);
+    WriteParam(aWriter, aParam.mScreenPoint);
+    WriteParam(aWriter, aParam.mLocalScreenPoint);
+    WriteParam(aWriter, aParam.mRadius);
+    WriteParam(aWriter, aParam.mRotationAngle);
+    WriteParam(aWriter, aParam.mForce);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return (ReadParam(aReader, &aResult->mTimeStamp) &&
+            ReadParam(aReader, &aResult->mScreenPoint) &&
+            ReadParam(aReader, &aResult->mLocalScreenPoint) &&
+            ReadParam(aReader, &aResult->mRadius) &&
+            ReadParam(aReader, &aResult->mRotationAngle) &&
+            ReadParam(aReader, &aResult->mForce));
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::SingleTouchData> {
+  using paramType = mozilla::SingleTouchData;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, aParam.mHistoricalData);
+    WriteParam(aWriter, aParam.mIdentifier);
+    WriteParam(aWriter, aParam.mScreenPoint);
+    WriteParam(aWriter, aParam.mLocalScreenPoint);
+    WriteParam(aWriter, aParam.mRadius);
+    WriteParam(aWriter, aParam.mRotationAngle);
+    WriteParam(aWriter, aParam.mForce);
+    WriteParam(aWriter, aParam.mTiltX);
+    WriteParam(aWriter, aParam.mTiltY);
+    WriteParam(aWriter, aParam.mTwist);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return (ReadParam(aReader, &aResult->mHistoricalData) &&
+            ReadParam(aReader, &aResult->mIdentifier) &&
+            ReadParam(aReader, &aResult->mScreenPoint) &&
+            ReadParam(aReader, &aResult->mLocalScreenPoint) &&
+            ReadParam(aReader, &aResult->mRadius) &&
+            ReadParam(aReader, &aResult->mRotationAngle) &&
+            ReadParam(aReader, &aResult->mForce) &&
+            ReadParam(aReader, &aResult->mTiltX) &&
+            ReadParam(aReader, &aResult->mTiltY) &&
+            ReadParam(aReader, &aResult->mTwist));
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::MultiTouchInput::MultiTouchType>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::MultiTouchInput::MultiTouchType,
+          mozilla::MultiTouchInput::MultiTouchType::MULTITOUCH_START,
+          mozilla::MultiTouchInput::sHighestMultiTouchType> {};
+
+template <>
+struct ParamTraits<mozilla::MultiTouchInput> {
+  using paramType = mozilla::MultiTouchInput;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::InputData&>(aParam));
+    WriteParam(aWriter, aParam.mType);
+    WriteParam(aWriter, aParam.mTouches);
+    WriteParam(aWriter, aParam.mHandledByAPZ);
+    WriteParam(aWriter, aParam.mScreenOffset);
+    WriteParam(aWriter, aParam.mButton);
+    WriteParam(aWriter, aParam.mButtons);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, static_cast<mozilla::InputData*>(aResult)) &&
+           ReadParam(aReader, &aResult->mType) &&
+           ReadParam(aReader, &aResult->mTouches) &&
+           ReadParam(aReader, &aResult->mHandledByAPZ) &&
+           ReadParam(aReader, &aResult->mScreenOffset) &&
+           ReadParam(aReader, &aResult->mButton) &&
+           ReadParam(aReader, &aResult->mButtons);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::MouseInput::MouseType>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::MouseInput::MouseType,
+          mozilla::MouseInput::MouseType::MOUSE_NONE,
+          mozilla::MouseInput::sHighestMouseType> {};
+
+template <>
+struct ParamTraits<mozilla::MouseInput::ButtonType>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::MouseInput::ButtonType,
+          mozilla::MouseInput::ButtonType::PRIMARY_BUTTON,
+          mozilla::MouseInput::sHighestButtonType> {};
+
+template <>
+struct ParamTraits<mozilla::MouseInput> {
+  using paramType = mozilla::MouseInput;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::InputData&>(aParam));
+    WriteParam(aWriter, aParam.mButtonType);
+    WriteParam(aWriter, aParam.mType);
+    WriteParam(aWriter, aParam.mInputSource);
+    WriteParam(aWriter, aParam.mButtons);
+    WriteParam(aWriter, aParam.mOrigin);
+    WriteParam(aWriter, aParam.mLocalOrigin);
+    WriteParam(aWriter, aParam.mHandledByAPZ);
+    WriteParam(aWriter, aParam.mPreventClickEvent);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, static_cast<mozilla::InputData*>(aResult)) &&
+           ReadParam(aReader, &aResult->mButtonType) &&
+           ReadParam(aReader, &aResult->mType) &&
+           ReadParam(aReader, &aResult->mInputSource) &&
+           ReadParam(aReader, &aResult->mButtons) &&
+           ReadParam(aReader, &aResult->mOrigin) &&
+           ReadParam(aReader, &aResult->mLocalOrigin) &&
+           ReadParam(aReader, &aResult->mHandledByAPZ) &&
+           ReadParam(aReader, &aResult->mPreventClickEvent);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::PanGestureInput::PanGestureType>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::PanGestureInput::PanGestureType,
+          mozilla::PanGestureInput::PanGestureType::PANGESTURE_MAYSTART,
+          mozilla::PanGestureInput::sHighestPanGestureType> {};
+
+template <>
+struct ParamTraits<mozilla::PanGestureInput::PanDeltaType>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::PanGestureInput::PanDeltaType,
+          mozilla::PanGestureInput::PanDeltaType::PANDELTA_PAGE,
+          mozilla::PanGestureInput::sHighestPanDeltaType> {};
+
+template <>
+struct ParamTraits<mozilla::PanGestureInput>
+    : BitfieldHelper<mozilla::PanGestureInput> {
+  using paramType = mozilla::PanGestureInput;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::InputData&>(aParam));
+    WriteParam(aWriter, aParam.mType);
+    WriteParam(aWriter, aParam.mPanStartPoint);
+    WriteParam(aWriter, aParam.mPanDisplacement);
+    WriteParam(aWriter, aParam.mLocalPanStartPoint);
+    WriteParam(aWriter, aParam.mLocalPanDisplacement);
+    WriteParam(aWriter, aParam.mLineOrPageDeltaX);
+    WriteParam(aWriter, aParam.mLineOrPageDeltaY);
+    WriteParam(aWriter, aParam.mUserDeltaMultiplierX);
+    WriteParam(aWriter, aParam.mUserDeltaMultiplierY);
+    WriteParam(aWriter, aParam.mDeltaType);
+    WriteParam(aWriter, aParam.mHandledByAPZ);
+    WriteParam(aWriter, aParam.mMayTriggerSwipe);
+    WriteParam(aWriter, aParam.mOverscrollBehaviorAllowsSwipe);
+    WriteParam(aWriter, aParam.mSimulateMomentum);
+    WriteParam(aWriter, aParam.mIsNoLineOrPageDelta);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, static_cast<mozilla::InputData*>(aResult)) &&
+           ReadParam(aReader, &aResult->mType) &&
+           ReadParam(aReader, &aResult->mPanStartPoint) &&
+           ReadParam(aReader, &aResult->mPanDisplacement) &&
+           ReadParam(aReader, &aResult->mLocalPanStartPoint) &&
+           ReadParam(aReader, &aResult->mLocalPanDisplacement) &&
+           ReadParam(aReader, &aResult->mLineOrPageDeltaX) &&
+           ReadParam(aReader, &aResult->mLineOrPageDeltaY) &&
+           ReadParam(aReader, &aResult->mUserDeltaMultiplierX) &&
+           ReadParam(aReader, &aResult->mUserDeltaMultiplierY) &&
+           ReadParam(aReader, &aResult->mDeltaType) &&
+           ReadBoolForBitfield(aReader, aResult, &paramType::SetHandledByAPZ) &&
+           ReadBoolForBitfield(aReader, aResult,
+                               &paramType::SetMayTriggerSwipe) &&
+           ReadBoolForBitfield(aReader, aResult,
+                               &paramType::SetOverscrollBehaviorAllowsSwipe) &&
+           ReadBoolForBitfield(aReader, aResult,
+                               &paramType::SetSimulateMomentum) &&
+           ReadBoolForBitfield(aReader, aResult,
+                               &paramType::SetIsNoLineOrPageDelta);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::PinchGestureInput::PinchGestureType>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::PinchGestureInput::PinchGestureType,
+          mozilla::PinchGestureInput::PinchGestureType::PINCHGESTURE_START,
+          mozilla::PinchGestureInput::sHighestPinchGestureType> {};
+
+template <>
+struct ParamTraits<mozilla::PinchGestureInput::PinchGestureSource>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::PinchGestureInput::PinchGestureSource,
+          // Set the min to TOUCH, to ensure UNKNOWN is never sent over IPC
+          mozilla::PinchGestureInput::PinchGestureSource::TOUCH,
+          mozilla::PinchGestureInput::sHighestPinchGestureSource> {};
+
+template <>
+struct ParamTraits<mozilla::PinchGestureInput> {
+  using paramType = mozilla::PinchGestureInput;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::InputData&>(aParam));
+    WriteParam(aWriter, aParam.mType);
+    WriteParam(aWriter, aParam.mSource);
+    WriteParam(aWriter, aParam.mScreenOffset);
+    WriteParam(aWriter, aParam.mFocusPoint);
+    WriteParam(aWriter, aParam.mLocalFocusPoint);
+    WriteParam(aWriter, aParam.mCurrentSpan);
+    WriteParam(aWriter, aParam.mPreviousSpan);
+    WriteParam(aWriter, aParam.mLineOrPageDeltaY);
+    WriteParam(aWriter, aParam.mHandledByAPZ);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, static_cast<mozilla::InputData*>(aResult)) &&
+           ReadParam(aReader, &aResult->mType) &&
+           ReadParam(aReader, &aResult->mSource) &&
+           ReadParam(aReader, &aResult->mScreenOffset) &&
+           ReadParam(aReader, &aResult->mFocusPoint) &&
+           ReadParam(aReader, &aResult->mLocalFocusPoint) &&
+           ReadParam(aReader, &aResult->mCurrentSpan) &&
+           ReadParam(aReader, &aResult->mPreviousSpan) &&
+           ReadParam(aReader, &aResult->mLineOrPageDeltaY) &&
+           ReadParam(aReader, &aResult->mHandledByAPZ);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::TapGestureInput::TapGestureType>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::TapGestureInput::TapGestureType,
+          mozilla::TapGestureInput::TapGestureType::TAPGESTURE_LONG,
+          mozilla::TapGestureInput::sHighestTapGestureType> {};
+
+template <>
+struct ParamTraits<mozilla::TapGestureInput> {
+  using paramType = mozilla::TapGestureInput;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::InputData&>(aParam));
+    WriteParam(aWriter, aParam.mType);
+    WriteParam(aWriter, aParam.mPoint);
+    WriteParam(aWriter, aParam.mLocalPoint);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, static_cast<mozilla::InputData*>(aResult)) &&
+           ReadParam(aReader, &aResult->mType) &&
+           ReadParam(aReader, &aResult->mPoint) &&
+           ReadParam(aReader, &aResult->mLocalPoint);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::ScrollWheelInput::ScrollDeltaType>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::ScrollWheelInput::ScrollDeltaType,
+          mozilla::ScrollWheelInput::ScrollDeltaType::SCROLLDELTA_LINE,
+          mozilla::ScrollWheelInput::sHighestScrollDeltaType> {};
+
+template <>
+struct ParamTraits<mozilla::ScrollWheelInput::ScrollMode>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::ScrollWheelInput::ScrollMode,
+          mozilla::ScrollWheelInput::ScrollMode::SCROLLMODE_INSTANT,
+          mozilla::ScrollWheelInput::sHighestScrollMode> {};
+
+template <>
+struct ParamTraits<mozilla::WheelDeltaAdjustmentStrategy>
+    : public ContiguousEnumSerializer<
+          mozilla::WheelDeltaAdjustmentStrategy,
+          mozilla::WheelDeltaAdjustmentStrategy(0),
+          mozilla::WheelDeltaAdjustmentStrategy::eSentinel> {};
+
+template <>
+struct ParamTraits<mozilla::layers::APZWheelAction>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::layers::APZWheelAction,
+          mozilla::layers::APZWheelAction::Scroll,
+          mozilla::layers::kHighestAPZWheelAction> {};
+
+template <>
+struct ParamTraits<mozilla::ScrollWheelInput> {
+  using paramType = mozilla::ScrollWheelInput;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::InputData&>(aParam));
+    WriteParam(aWriter, aParam.mDeltaType);
+    WriteParam(aWriter, aParam.mScrollMode);
+    WriteParam(aWriter, aParam.mOrigin);
+    WriteParam(aWriter, aParam.mHandledByAPZ);
+    WriteParam(aWriter, aParam.mDeltaX);
+    WriteParam(aWriter, aParam.mDeltaY);
+    WriteParam(aWriter, aParam.mWheelTicksX);
+    WriteParam(aWriter, aParam.mWheelTicksY);
+    WriteParam(aWriter, aParam.mLocalOrigin);
+    WriteParam(aWriter, aParam.mLineOrPageDeltaX);
+    WriteParam(aWriter, aParam.mLineOrPageDeltaY);
+    WriteParam(aWriter, aParam.mScrollSeriesNumber);
+    WriteParam(aWriter, aParam.mUserDeltaMultiplierX);
+    WriteParam(aWriter, aParam.mUserDeltaMultiplierY);
+    WriteParam(aWriter, aParam.mMayHaveMomentum);
+    WriteParam(aWriter, aParam.mIsMomentum);
+    WriteParam(aWriter, aParam.mAllowToOverrideSystemScrollSpeed);
+    WriteParam(aWriter, aParam.mWheelDeltaAdjustmentStrategy);
+    WriteParam(aWriter, aParam.mAPZAction);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, static_cast<mozilla::InputData*>(aResult)) &&
+           ReadParam(aReader, &aResult->mDeltaType) &&
+           ReadParam(aReader, &aResult->mScrollMode) &&
+           ReadParam(aReader, &aResult->mOrigin) &&
+           ReadParam(aReader, &aResult->mHandledByAPZ) &&
+           ReadParam(aReader, &aResult->mDeltaX) &&
+           ReadParam(aReader, &aResult->mDeltaY) &&
+           ReadParam(aReader, &aResult->mWheelTicksX) &&
+           ReadParam(aReader, &aResult->mWheelTicksY) &&
+           ReadParam(aReader, &aResult->mLocalOrigin) &&
+           ReadParam(aReader, &aResult->mLineOrPageDeltaX) &&
+           ReadParam(aReader, &aResult->mLineOrPageDeltaY) &&
+           ReadParam(aReader, &aResult->mScrollSeriesNumber) &&
+           ReadParam(aReader, &aResult->mUserDeltaMultiplierX) &&
+           ReadParam(aReader, &aResult->mUserDeltaMultiplierY) &&
+           ReadParam(aReader, &aResult->mMayHaveMomentum) &&
+           ReadParam(aReader, &aResult->mIsMomentum) &&
+           ReadParam(aReader, &aResult->mAllowToOverrideSystemScrollSpeed) &&
+           ReadParam(aReader, &aResult->mWheelDeltaAdjustmentStrategy) &&
+           ReadParam(aReader, &aResult->mAPZAction);
+  }
+};
+
+template <>
+struct ParamTraits<mozilla::KeyboardInput::KeyboardEventType>
+    : public ContiguousEnumSerializer<
+          mozilla::KeyboardInput::KeyboardEventType,
+          mozilla::KeyboardInput::KeyboardEventType::KEY_DOWN,
+          mozilla::KeyboardInput::KeyboardEventType::KEY_SENTINEL> {};
+
+template <>
+struct ParamTraits<mozilla::KeyboardInput> {
+  using paramType = mozilla::KeyboardInput;
+
+  static void Write(MessageWriter* aWriter, const paramType& aParam) {
+    WriteParam(aWriter, static_cast<const mozilla::InputData&>(aParam));
+    WriteParam(aWriter, aParam.mType);
+    WriteParam(aWriter, aParam.mKeyCode);
+    WriteParam(aWriter, aParam.mCharCode);
+    WriteParam(aWriter, aParam.mShortcutCandidates);
+    WriteParam(aWriter, aParam.mHandledByAPZ);
+  }
+
+  static bool Read(MessageReader* aReader, paramType* aResult) {
+    return ReadParam(aReader, static_cast<mozilla::InputData*>(aResult)) &&
+           ReadParam(aReader, &aResult->mType) &&
+           ReadParam(aReader, &aResult->mKeyCode) &&
+           ReadParam(aReader, &aResult->mCharCode) &&
+           ReadParam(aReader, &aResult->mShortcutCandidates) &&
+           ReadParam(aReader, &aResult->mHandledByAPZ);
+  }
+};
+
+}  // namespace IPC
+
+#endif  // nsGUIEventIPC_h__
diff --git a/widget/nsHTMLFormatConverter.cpp b/widget/nsHTMLFormatConverter.cpp
new file mode 100644
index 0000000000..4898fd2c8b
--- /dev/null
+++ b/widget/nsHTMLFormatConverter.cpp
@@ -0,0 +1,184 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsHTMLFormatConverter.h"
+
+#include "nsArray.h"
+#include "nsCRT.h"
+#include "nsCOMPtr.h"
+#include "nsITransferable.h"
+#include "nsLiteralString.h"
+#include "nsXPCOM.h"
+#include "nsISupportsPrimitives.h"
+
+// HTML convertor stuff
+#include "nsPrimitiveHelpers.h"
+#include "nsIDocumentEncoder.h"
+#include "nsContentUtils.h"
+
+nsHTMLFormatConverter::nsHTMLFormatConverter() = default;
+
+nsHTMLFormatConverter::~nsHTMLFormatConverter() = default;
+
+NS_IMPL_ISUPPORTS(nsHTMLFormatConverter, nsIFormatConverter)
+
+//
+// GetInputDataFlavors
+//
+// Creates a new list and returns the list of all the flavors this converter
+// knows how to import. In this case, it's just HTML.
+//
+NS_IMETHODIMP
+nsHTMLFormatConverter::GetInputDataFlavors(nsTArray<nsCString>& aFlavors) {
+  aFlavors.AppendElement(nsLiteralCString(kHTMLMime));
+  return NS_OK;
+}
+
+//
+// GetOutputDataFlavors
+//
+// Creates a new list and returns the list of all the flavors this converter
+// knows how to export (convert). In this case, it's all sorts of things that
+// HTML can be converted to.
+//
+NS_IMETHODIMP
+nsHTMLFormatConverter::GetOutputDataFlavors(nsTArray<nsCString>& aFlavors) {
+  aFlavors.AppendElement(nsLiteralCString(kHTMLMime));
+  aFlavors.AppendElement(nsLiteralCString(kTextMime));
+  return NS_OK;
+}
+
+//
+// CanConvert
+//
+// Determines if we support the given conversion. Currently, this method only
+// converts from HTML to others.
+//
+NS_IMETHODIMP
+nsHTMLFormatConverter::CanConvert(const char* aFromDataFlavor,
+                                  const char* aToDataFlavor, bool* _retval) {
+  if (!_retval) return NS_ERROR_INVALID_ARG;
+
+  *_retval = false;
+  if (!nsCRT::strcmp(aFromDataFlavor, kHTMLMime)) {
+    if (!nsCRT::strcmp(aToDataFlavor, kHTMLMime)) {
+      *_retval = true;
+    } else if (!nsCRT::strcmp(aToDataFlavor, kTextMime)) {
+      *_retval = true;
+    }
+#if NOT_NOW
+    // pinkerton
+    // no one uses this flavor right now, so it's just slowing things down. If
+    // anyone cares I can put it back in.
+    else if (toFlavor.Equals(kAOLMailMime))
+      *_retval = true;
+#endif
+  }
+  return NS_OK;
+
+}  // CanConvert
+
+//
+// Convert
+//
+// Convert data from one flavor to another. The data is wrapped in primitive
+// objects so that it is accessible from JS. Currently, this only accepts HTML
+// input, so anything else is invalid.
+//
+// XXX This method copies the data WAAAAY too many time for my liking. Grrrrrr.
+// Mostly it's because
+// XXX we _must_ put things into nsStrings so that the parser will accept it.
+// Lame lame lame lame. We
+// XXX also can't just get raw unicode out of the nsString, so we have to
+// allocate heap to get
+// XXX unicode out of the string. Lame lame lame.
+//
+NS_IMETHODIMP
+nsHTMLFormatConverter::Convert(const char* aFromDataFlavor,
+                               nsISupports* aFromData,
+                               const char* aToDataFlavor,
+                               nsISupports** aToData) {
+  if (!aToData) return NS_ERROR_INVALID_ARG;
+
+  nsresult rv = NS_OK;
+  *aToData = nullptr;
+
+  if (!nsCRT::strcmp(aFromDataFlavor, kHTMLMime)) {
+    nsAutoCString toFlavor(aToDataFlavor);
+
+    // HTML on clipboard is going to always be double byte so it will be in a
+    // primitive class of nsISupportsString. Also, since the data is in two byte
+    // chunks the length represents the length in 1-byte chars, so we need to
+    // divide by two.
+    nsCOMPtr<nsISupportsString> dataWrapper0(do_QueryInterface(aFromData));
+    if (!dataWrapper0) {
+      return NS_ERROR_INVALID_ARG;
+    }
+
+    nsAutoString dataStr;
+    dataWrapper0->GetData(dataStr);  // COPY #1
+    // note: conversion to text/plain is done inside the clipboard. we do not
+    // need to worry about it here.
+    if (toFlavor.Equals(kHTMLMime) || toFlavor.Equals(kTextMime)) {
+      nsresult res;
+      if (toFlavor.Equals(kHTMLMime)) {
+        int32_t dataLen = dataStr.Length() * 2;
+        nsPrimitiveHelpers::CreatePrimitiveForData(toFlavor, dataStr.get(),
+                                                   dataLen, aToData);
+      } else {
+        nsAutoString outStr;
+        res = ConvertFromHTMLToUnicode(dataStr, outStr);
+        if (NS_SUCCEEDED(res)) {
+          int32_t dataLen = outStr.Length() * 2;
+          nsPrimitiveHelpers::CreatePrimitiveForData(toFlavor, outStr.get(),
+                                                     dataLen, aToData);
+        }
+      }
+    }  // else if HTML or Unicode
+    else if (toFlavor.Equals(kAOLMailMime)) {
+      nsAutoString outStr;
+      if (NS_SUCCEEDED(ConvertFromHTMLToAOLMail(dataStr, outStr))) {
+        int32_t dataLen = outStr.Length() * 2;
+        nsPrimitiveHelpers::CreatePrimitiveForData(toFlavor, outStr.get(),
+                                                   dataLen, aToData);
+      }
+    }  // else if AOL mail
+    else {
+      rv = NS_ERROR_FAILURE;
+    }
+  }  // if we got html mime
+  else
+    rv = NS_ERROR_FAILURE;
+
+  return rv;
+
+}  // Convert
+
+//
+// ConvertFromHTMLToUnicode
+//
+// Takes HTML and converts it to plain text but in unicode.
+//
+NS_IMETHODIMP
+nsHTMLFormatConverter::ConvertFromHTMLToUnicode(const nsAutoString& aFromStr,
+                                                nsAutoString& aToStr) {
+  return nsContentUtils::ConvertToPlainText(
+      aFromStr, aToStr,
+      nsIDocumentEncoder::OutputSelectionOnly |
+          nsIDocumentEncoder::OutputAbsoluteLinks |
+          nsIDocumentEncoder::OutputNoScriptContent |
+          nsIDocumentEncoder::OutputNoFramesContent,
+      0);
+}  // ConvertFromHTMLToUnicode
+
+NS_IMETHODIMP
+nsHTMLFormatConverter::ConvertFromHTMLToAOLMail(const nsAutoString& aFromStr,
+                                                nsAutoString& aToStr) {
+  aToStr.AssignLiteral("<HTML>");
+  aToStr.Append(aFromStr);
+  aToStr.AppendLiteral("</HTML>");
+
+  return NS_OK;
+}
diff --git a/widget/nsHTMLFormatConverter.h b/widget/nsHTMLFormatConverter.h
new file mode 100644
index 0000000000..f01373233b
--- /dev/null
+++ b/widget/nsHTMLFormatConverter.h
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsHTMLFormatConverter_h__
+#define nsHTMLFormatConverter_h__
+
+#include "nsCOMPtr.h"
+#include "nsIFormatConverter.h"
+#include "nsString.h"
+
+class nsIMutableArray;
+
+class nsHTMLFormatConverter : public nsIFormatConverter {
+ public:
+  nsHTMLFormatConverter();
+
+  // nsISupports
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIFORMATCONVERTER
+
+ protected:
+  virtual ~nsHTMLFormatConverter();
+
+  NS_IMETHOD ConvertFromHTMLToUnicode(const nsAutoString& aFromStr,
+                                      nsAutoString& aToStr);
+  NS_IMETHOD ConvertFromHTMLToAOLMail(const nsAutoString& aFromStr,
+                                      nsAutoString& aToStr);
+};
+
+#endif  // nsHTMLFormatConverter_h__
diff --git a/widget/nsIAppShell.idl b/widget/nsIAppShell.idl
new file mode 100644
index 0000000000..f2ea8ab166
--- /dev/null
+++ b/widget/nsIAppShell.idl
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIRunnable;
+%{ C++
+template <class T> struct already_AddRefed;
+
+/**
+ * After the default timezone changes, this topic is notified. Some systems may
+ * not support monitoring timezone.
+ */
+#define DEFAULT_TIMEZONE_CHANGED_OBSERVER_TOPIC "default-timezone-changed"
+%}
+
+/**
+ * Interface for the native event system layer.  This interface is designed
+ * to be used on the main application thread only.
+ */
+[uuid(7cd5c71d-223b-4afe-931d-5eedb1f2b01f)]
+interface nsIAppShell : nsISupports
+{
+  /**
+   * Enter an event loop.  Don't leave until exit() is called.
+   */
+  void run();
+
+  /**
+   * Exit the handle event loop
+   */
+  void exit();
+
+  /**
+   * Ask the native event queue notification mechanism to favor Gecko tasks
+   * (instead of native tasks) for a short while. (Content processes always
+   * favor Gecko tasks.)
+   */
+  void geckoTaskBurst();
+
+  /**
+   * Suspends the use of additional platform-specific methods (besides the
+   * nsIAppShell->run() event loop) to run Gecko events on the main
+   * application thread.  Under some circumstances these "additional methods"
+   * can cause Gecko event handlers to be re-entered, sometimes leading to
+   * hangs and crashes.  Calls to suspendNative() and resumeNative() may be
+   * nested.  On some platforms (those that don't use any "additional
+   * methods") this will be a no-op.  Does not (in itself) stop Gecko events
+   * from being processed on the main application thread.  But if the
+   * nsIAppShell->run() event loop is blocked when this call is made, Gecko
+   * events will stop being processed until resumeNative() is called (even
+   * if a plugin or library is temporarily processing events on a nested
+   * event loop).
+   */
+  void suspendNative();
+
+  /**
+   * Resumes the use of additional platform-specific methods to run Gecko
+   * events on the main application thread.  Calls to suspendNative() and
+   * resumeNative() may be nested.  On some platforms this will be a no-op.
+   */
+  void resumeNative();
+
+  /**
+   * The current event loop nesting level.
+   */
+  readonly attribute unsigned long eventloopNestingLevel;
+};
diff --git a/widget/nsIApplicationChooser.idl b/widget/nsIApplicationChooser.idl
new file mode 100644
index 0000000000..f3da903a10
--- /dev/null
+++ b/widget/nsIApplicationChooser.idl
@@ -0,0 +1,39 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "nsIMIMEInfo.idl"
+
+interface mozIDOMWindowProxy;
+
+[scriptable, function, uuid(8144404d-e6c7-4861-bcca-47de912ee811)]
+interface nsIApplicationChooserFinishedCallback : nsISupports
+{
+  void done(in nsIHandlerApp handlerApp);
+};
+
+[scriptable, uuid(f7a149da-612a-46ba-8a2f-54786fc28791)]
+interface nsIApplicationChooser : nsISupports
+{
+ /**
+  * Initialize the application chooser picker widget.  The application chooser
+  * is not valid until this method is called.
+  *
+  * @param      parent   nsIDOMWindow parent.  This dialog will be dependent
+  *                      on this parent. parent must be non-null.
+  * @param      title    The title for the file widget
+  *
+  */
+  void init(in mozIDOMWindowProxy parent, in ACString title);
+
+  /**
+   * Open application chooser dialog.
+   *
+   * @param    contentType   content type of file to open
+   * @param    applicationChooserFinishedCallback  callback fuction to run when dialog is closed
+   */
+  void open(in ACString contentType, in nsIApplicationChooserFinishedCallback applicationChooserFinishedCallback);
+};
diff --git a/widget/nsIBaseWindow.cpp b/widget/nsIBaseWindow.cpp
new file mode 100644
index 0000000000..a9ebdcc860
--- /dev/null
+++ b/widget/nsIBaseWindow.cpp
@@ -0,0 +1,14 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIBaseWindow.h"
+#include "mozilla/LookAndFeel.h"
+
+using namespace mozilla;
+
+CSSToLayoutDeviceScale nsIBaseWindow::UnscaledDevicePixelsPerCSSPixel() {
+  return CSSToLayoutDeviceScale(GetWidgetCSSToDeviceScale() *
+                                LookAndFeel::SystemZoomSettings().mFullZoom);
+}
diff --git a/widget/nsIBaseWindow.idl b/widget/nsIBaseWindow.idl
new file mode 100644
index 0000000000..3cf7193788
--- /dev/null
+++ b/widget/nsIBaseWindow.idl
@@ -0,0 +1,296 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "nsrootidl.idl"
+/*#include "nsIWidget.idl"  Boy this would be nice.*/
+
+[ptr] native nsIWidget(nsIWidget);
+%{C++
+#include "Units.h"
+#include "mozilla/DimensionRequest.h"
+
+class nsIWidget;
+%}
+
+typedef voidPtr nativeWindow;
+native DimensionRequest(mozilla::DimensionRequest&&);
+native DimensionKind(mozilla::DimensionKind);
+
+/**
+ * The nsIBaseWindow describes a generic window and basic operations that
+ * can be performed on it.  This is not to be a complete windowing interface
+ * but rather a common set that nearly all windowed objects support.
+ */
+
+[scriptable, builtinclass, uuid(ca635529-a977-4552-9b8a-66187e54d882)]
+interface nsIBaseWindow : nsISupports
+{
+  /*
+  Allows a client to initialize an object implementing this interface with
+  the usually required window setup information.
+  It is possible to pass null for both parentNativeWindow and parentWidget,
+  but only docshells support this.
+
+  @param parentNativeWindow - This allows a system to pass in the parenting
+    window as a native reference rather than relying on the calling
+    application to have created the parent window as an nsIWidget.  This
+    value will be ignored (should be nullptr) if an nsIWidget is passed in to
+    the parentWidget parameter.
+
+  @param parentWidget - This allows a system to pass in the parenting widget.
+    This allows some objects to optimize themselves and rely on the view
+    system for event flow rather than creating numerous native windows.  If
+    one of these is not available, nullptr should be passed.
+
+  @param x - This is the x co-ordinate relative to the parent to place the
+    window.
+
+  @param y - This is the y co-ordinate relative to the parent to place the
+    window.
+
+  @param cx - This is the width  for the window to be.
+
+  @param cy - This is the height for the window to be.
+
+  @return  NS_OK - Window Init succeeded without a problem.
+        NS_ERROR_UNEXPECTED - Call was unexpected at this time. Perhaps
+          initWindow() had already been called.
+        NS_ERROR_INVALID_ARG - controls that require either a parentNativeWindow
+          or a parentWidget may return invalid arg when they do not
+          receive what they are needing.
+  */
+  [noscript]void initWindow(in nativeWindow parentNativeWindow,
+    in nsIWidget parentWidget,  in long x, in long y, in long cx, in long cy);
+
+  /*
+  Tell the window that it should destroy itself.  This call should not be
+  necessary as it will happen implictly when final release occurs on the
+  object.  If for some reaons you want the window destroyed prior to release
+  due to cycle or ordering issues, then this call provides that ability.
+
+  @return  NS_OK - Everything destroyed properly.
+        NS_ERROR_UNEXPECTED - This call was unexpected at this time.
+          Perhaps create() has not been called yet.
+  */
+  void destroy();
+
+  /*
+  Sets the current x and y coordinates of the control.  This is relative to
+  the parent window.
+  */
+  void setPosition(in long x, in long y);
+
+  /*
+  Ditto, with arguments in global desktop pixels rather than (potentially
+  ambiguous) device pixels
+  */
+  void setPositionDesktopPix(in long x, in long y);
+
+  /*
+  Gets the current x and y coordinates of the control.  This is relative to the
+  parent window.
+  */
+  void getPosition(out long x, out long y);
+
+%{C++
+  mozilla::LayoutDeviceIntPoint GetPosition() {
+    int32_t x = 0, y = 0;
+    GetPosition(&x, &y);
+    return mozilla::LayoutDeviceIntPoint(x, y);
+  }
+%}
+
+  /*
+  Sets the width and height of the control.
+  */
+  void setSize(in long cx, in long cy, in boolean fRepaint);
+
+  /*
+  Gets the width and height of the control.
+  */
+  void getSize(out long cx, out long cy);
+
+%{C++
+  mozilla::LayoutDeviceIntSize GetSize() {
+    int32_t w = 0, h = 0;
+    GetSize(&w, &h);
+    return mozilla::LayoutDeviceIntSize(w, h);
+  }
+%}
+
+  /**
+   * The 'flags' argument to setPositionAndSize is a set of these bits.
+   */
+  const unsigned long eRepaint = 1;
+  const unsigned long eDelayResize = 2;
+
+  /*
+  Convenience function combining the SetPosition and SetSize into one call.
+  Also is more efficient than calling both.
+  */
+  void setPositionAndSize(in long x, in long y, in long cx, in long cy,
+    in unsigned long flags);
+
+  /*
+  Convenience function combining the GetPosition and GetSize into one call.
+  Also is more efficient than calling both.
+  */
+  void getPositionAndSize(out long x, out long y, out long cx, out long cy);
+
+%{C++
+  mozilla::LayoutDeviceIntRect GetPositionAndSize() {
+    int32_t x = 0, y = 0, w = 0, h = 0;
+    GetPositionAndSize(&x, &y, &w, &h);
+    return mozilla::LayoutDeviceIntRect(x, y, w, h);
+  }
+%}
+
+  /**
+   * Allows to request the change of individual dimensions without specifying
+   * the other components.
+   *
+   * @param aRequest - The requested change. A request to change only the width
+   *                   may look like:
+   *                   {DimensionKind::Outer, Nothing(), Nothing(), Some(20), Nothing()}
+   *
+   * Note: Inner position is not supported.
+   *
+   * @see DimensionRequest
+   */
+  void setDimensions(in DimensionRequest aRequest);
+
+  /**
+   * Gets the dimensions of the window. The caller may pass nullptr for any
+   * value it is uninterested in receiving.
+   *
+   * @param aDimensionKind  Specifies whether the dimensions are in reference
+   *                        to the inner or outer dimensions.
+   * @param aX              Left hand corner of the outer area; or nullptr.
+   * @param aY              Top corner of the outer area; or nullptr.
+   * @param aCX             Width of the inner or outer area; or nullptr.
+   * @param aCY             Height of the inner or outer area; or nullptr.
+   *
+   * Note: Inner position is not supported.
+   *
+   * @see DimensionRequest
+   */
+  void getDimensions(in DimensionKind aDimensionKind, out long aX, out long aY, out long aCX, out long aCY);
+
+  /**
+   * Tell the window to repaint itself
+   * @param aForce - if true, repaint immediately
+   *                 if false, the window may defer repainting as it sees fit.
+   */
+  void repaint(in boolean force);
+
+  /*
+  This is the parenting widget for the control.  This may be null if the
+  native window was handed in for the parent during initialization.
+  If this  is returned, it should refer to the same object as
+  parentNativeWindow.
+
+  Setting this after Create() has been called may not be supported by some
+  implementations.
+
+  On controls that don't support widgets, setting this will return a
+  NS_ERROR_NOT_IMPLEMENTED error.
+  */
+  [noscript] attribute nsIWidget parentWidget;
+
+  /*
+  This is the native window parent of the control.
+
+  Setting this after Create() has been called may not be supported by some
+  implementations.
+
+  On controls that don't support setting nativeWindow parents, setting this
+  will return a NS_ERROR_NOT_IMPLEMENTED error.
+  */
+  attribute nativeWindow parentNativeWindow;
+
+  /*
+  This is the handle (HWND, GdkWindow*, ...) to the native window of the
+  control, exposed as an AString.
+
+  @return AString in hex format with "0x" prepended, or empty string if
+  mainWidget undefined
+
+  @throws NS_ERROR_NOT_IMPLEMENTED for non-XULWindows
+  */
+  readonly attribute AString nativeHandle;
+
+  /*
+  Attribute controls the visibility of the object behind this interface.
+  Setting this attribute to false will hide the control.  Setting it to
+  true will show it.
+  */
+  attribute boolean visibility;
+
+  /*
+  a disabled window should accept no user interaction; it's a dead window,
+  like the parent of a modal window.
+  */
+  attribute boolean enabled;
+
+  /*
+  Allows you to find out what the widget is of a given object.  Depending
+  on the object, this may return the parent widget in which this object
+  lives if it has not had to create its own widget.
+  */
+  [noscript] readonly attribute nsIWidget mainWidget;
+
+  /*
+  The number of device pixels per CSS pixel used by this window's widget at the
+  default full zoom level.
+  This is the value returned by GetDefaultScale() of the underlying widget.
+  Note that this may change if the window is moved between screens with
+  differing resolutions.
+  NOTE: This is mostly an implementation detail of
+  UnscaledDevicePixelsPerCSSPixel, which is what you probably want to use.
+  */
+  [noscript, notxpcom, nostdcall] readonly attribute double widgetCSSToDeviceScale;
+
+%{C++
+  // The number of device pixels per CSS pixel used on this window's current
+  // screen at the default full zoom level.
+  //
+  // This is the widget scale _plus_ the OS zoom scale if appropriate.
+  // Implemented in AppWindow.cpp
+  mozilla::CSSToLayoutDeviceScale UnscaledDevicePixelsPerCSSPixel();
+%}
+
+  /*
+  The number of device pixels per display pixel on this window's current
+  screen. (The meaning of "display pixel" varies across OS environments;
+  it is the pixel units used by the desktop environment to manage screen
+  real estate and window positioning, which may correspond to (per-screen)
+  device pixels, or may be a virtual coordinate space that covers a multi-
+  monitor, mixed-dpi desktop space.)
+  This is the value returned by GetDesktopToDeviceScale() of the underlying
+  widget.
+  Note that this may change if the window is moved between screens with
+  differing resolutions.
+  */
+  readonly attribute double devicePixelsPerDesktopPixel;
+
+%{C++
+  mozilla::DesktopToLayoutDeviceScale DevicePixelsPerDesktopPixel() {
+    double s = 1.0;
+    GetDevicePixelsPerDesktopPixel(&s);
+    return mozilla::DesktopToLayoutDeviceScale(s);
+  }
+
+  mozilla::CSSToDesktopScale GetUnscaledCSSToDesktopScale() {
+    return UnscaledDevicePixelsPerCSSPixel() / DevicePixelsPerDesktopPixel();
+  }
+%}
+
+  /*
+  Title of the window.
+  */
+  attribute AString title;
+};
diff --git a/widget/nsIBidiKeyboard.idl b/widget/nsIBidiKeyboard.idl
new file mode 100644
index 0000000000..1d41b2e79e
--- /dev/null
+++ b/widget/nsIBidiKeyboard.idl
@@ -0,0 +1,31 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[builtinclass, scriptable, uuid(288dae24-76e2-43a3-befe-9d9fabe8014e)]
+interface nsIBidiKeyboard : nsISupports
+{
+  /**
+   * Inspects the installed keyboards and resets the bidi keyboard state
+   */
+  void reset();
+
+  /**
+   * Determines if the current keyboard language is right-to-left
+   * @throws NS_ERROR_FAILURE if no right-to-left keyboards are installed
+   */
+  boolean isLangRTL();
+
+  /**
+   * Determines whether the system has at least one keyboard of each direction
+   * installed.
+   *
+   * @throws NS_ERROR_NOT_IMPLEMENTED if the widget layer does not provide this
+   * information.
+   */
+  readonly attribute boolean haveBidiKeyboards;
+};
diff --git a/widget/nsIClipboard.idl b/widget/nsIClipboard.idl
new file mode 100644
index 0000000000..5ed2d22600
--- /dev/null
+++ b/widget/nsIClipboard.idl
@@ -0,0 +1,215 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+#include "nsISupports.idl"
+#include "nsITransferable.idl"
+#include "nsIClipboardOwner.idl"
+
+interface nsIArray;
+
+webidl WindowContext;
+
+[scriptable, builtinclass, uuid(801e2318-c8fa-11ed-afa1-0242ac120002)]
+interface nsIAsyncSetClipboardData : nsISupports {
+  /**
+   * Provide the data for the set request.
+   *
+   * @param  aTransferable
+   *         The transferable contains the data to be written.
+   * @param  aOwner [optional]
+   *         The owner of the transferable.
+   */
+  void setData(in nsITransferable aTransferable, [optional] in nsIClipboardOwner aOwner);
+
+  /**
+   * Abort the request to set data.
+   *
+   * @param  aReason
+   *         The reason for the abort, can not be NS_OK.
+   */
+  void abort(in nsresult aReason);
+};
+
+[scriptable, function, uuid(78f7c18e-c8fa-11ed-afa1-0242ac120002)]
+interface nsIAsyncClipboardRequestCallback : nsISupports
+{
+  /**
+   * Indicates that the clipboard request has either succeeded, been canceled or
+   * rejected.
+   *
+   * @param  aResult
+   *         The result of the request. NS_OK if successful, or another value
+   *         that indicates the reason for failure or cancellation.
+   */
+  void onComplete(in nsresult aResult);
+};
+
+[scriptable, builtinclass, uuid(c18ea2f7-6b6f-4a38-9ab3-a8781fdfcc39)]
+interface nsIAsyncGetClipboardData : nsISupports {
+  /**
+   * Determines whether this request is still valid (e.g., the clipboard content
+   * associated with this request is not stale).
+   */
+  readonly attribute boolean valid;
+
+  /**
+   * The available flavors in the clipboard.
+   */
+  readonly attribute Array<ACString> flavorList;
+
+  /**
+   * Filters the flavors that `aTransferable` can import (see
+   * `nsITransferable::flavorsTransferableCanImport`). Every specified flavors
+   * must exist in `flavorList`, or the request will be rejected. If the request
+   * remains valid, it retrieves the data for the first flavor. The data is then
+   * set for `aTransferable`.
+   *
+   * @param  aTransferable
+   *         The transferable which contains the flavors to be read.
+   * @param  aCallback
+   *         The nsIAsyncClipboardRequestCallback to be invoked once the get
+   *         request is either successfully completed or rejected.
+   * @result NS_OK if no errors
+   */
+  void getData(in nsITransferable aTransferable,
+               in nsIAsyncClipboardRequestCallback aCallback);
+};
+
+[scriptable, uuid(ce23c1c4-58fd-4c33-8579-fa0796d9652c)]
+interface nsIAsyncClipboardGetCallback : nsISupports
+{
+  /**
+   * Indicates that the clipboard get request has succeeded.
+   */
+  void onSuccess(in nsIAsyncGetClipboardData aAsyncGetClipboardData);
+
+  /**
+   * Indicates that the clipboard get request has rejected.
+   *
+   * @param  aResult
+   *         The reason for the rejection, can not be NS_OK.
+   */
+  void onError(in nsresult aResult);
+};
+
+[scriptable, builtinclass, uuid(ceaa0047-647f-4b8e-ad1c-aff9fa62aa51)]
+interface nsIClipboard : nsISupports
+{
+    const long kSelectionClipboard = 0;
+    const long kGlobalClipboard = 1;
+    const long kFindClipboard = 2;
+    // Used to cache current selection on (nsClipboard) for macOS service menu.
+    const long kSelectionCache = 3;
+
+%{ C++
+    static const uint32_t kClipboardTypeCount = kSelectionCache + 1;
+%}
+
+   /**
+    * Given a transferable, set the data on the native clipboard
+    *
+    * @param  aTransferable The transferable
+    * @param  anOwner The owner of the transferable
+    * @param  aWhichClipboard Specifies the clipboard to which this operation applies.
+    * @result NS_Ok if no errors
+    */
+
+    void setData ( in nsITransferable aTransferable, in nsIClipboardOwner anOwner,
+                    in long aWhichClipboard ) ;
+
+    /**
+     * Requests setting data to the native clipboard. The acutal set occur
+     * when the data is provided by calling nsIAsyncSetClipboardData::setData().
+     * The result will be notified by nsIClipboardCallback. A new set request
+     * will cancel any prior pending requests, if any exist.
+     *
+     * @param  aWhichClipboard
+     *         Specifies the clipboard to which this operation applies.
+     * @param  aCallback [optional]
+     *         The callback object that will be notified upon completion.
+     * @return nsIAsyncSetClipboardData
+     *         The write request object. The actual write will occur when the
+     *         data is provided by calling nsIAsyncSetClipboardData::setData().
+     */
+    nsIAsyncSetClipboardData asyncSetData(in long aWhichClipboard,
+                                          [optional] in nsIAsyncClipboardRequestCallback aCallback);
+
+   /**
+    * Filters the flavors aTransferable can import (see
+    * `nsITransferable::flavorsTransferableCanImport`) and gets the data for the
+    * first flavor. That data is set for aTransferable.
+    *
+    * @param  aTransferable The transferable
+    * @param  aWhichClipboard Specifies the clipboard to which this operation applies.
+    * @param  aRequestingWindowContext [optional]
+    *         The window context window that is requesting the clipboard, which is
+    *         used for content analysis. Passing null means that the content is
+    *         exempt from content analysis. (for example, scripted clipboard read by
+    *         system code) This parameter should not be null when calling this from a
+    *         content process.
+    * @result NS_OK if no errors
+    */
+
+    void getData ( in nsITransferable aTransferable, in long aWhichClipboard, [optional] in WindowContext aRequestingWindowContext) ;
+
+    /**
+     * Requests getting data asynchronously from the native clipboard. This does
+     * not actually retrieve the data, but returns a nsIAsyncGetClipboardData
+     * contains current avaiable data formats. If the native clipboard is
+     * updated, either by us or other application, the existing
+     * nsIAsyncGetClipboardData becomes invalid.
+     *
+     * @param  aFlavorList
+     *         Specific data formats ('flavors') that can be retrieved from the
+     *         clipboard.
+     * @param  aWhichClipboard
+     *         Specifies the clipboard to which this operation applies.
+     * @param  aCallback
+     *         The callback object that will be notified upon completion.
+     * @result NS_OK if no errors
+     */
+    void asyncGetData(in Array<ACString> aFlavorList,
+                      in long aWhichClipboard,
+                      in WindowContext aRequestingWindowContext,
+                      in nsIPrincipal aRequestingPrincipal,
+                      in nsIAsyncClipboardGetCallback aCallback);
+
+   /**
+    * This empties the clipboard and notifies the clipboard owner.
+    * This empties the "logical" clipboard. It does not clear the native clipboard.
+    *
+    * @param  aWhichClipboard Specifies the clipboard to which this operation applies.
+    * @result NS_OK if successful.
+    */
+
+    void emptyClipboard ( in long aWhichClipboard ) ;
+
+   /**
+    * This provides a way to give correct UI feedback about, for instance, a paste
+    * should be allowed. It does _NOT_ actually retreive the data and should be a very
+    * inexpensive call. All it does is check if there is data on the clipboard matching
+    * any of the flavors in the given list.
+    *
+    * @param  aFlavorList     An array of ASCII strings.
+    * @param  aWhichClipboard Specifies the clipboard to which this operation applies.
+    * @outResult - if data is present matching one of
+    * @result NS_OK if successful.
+    */
+    boolean hasDataMatchingFlavors ( in Array<ACString> aFlavorList,
+                                     in long aWhichClipboard ) ;
+
+    /**
+     * Allows clients to determine if the implementation supports the concept of a
+     * separate clipboard.
+     *
+     * @param aWhichClipboard  Specifies the clipboard to which this operation applies.
+     * @outResult  true if the implementaion supports specific clipboard type.
+     * @result  NS_OK if successful.
+     */
+    [infallible]
+    boolean isClipboardTypeSupported(in long aWhichClipboard);
+};
diff --git a/widget/nsIClipboardHelper.idl b/widget/nsIClipboardHelper.idl
new file mode 100644
index 0000000000..ed4af112f1
--- /dev/null
+++ b/widget/nsIClipboardHelper.idl
@@ -0,0 +1,45 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "nsIClipboard.idl"
+
+%{ C++
+#include "nsString.h" // needed for AString -> nsAString, unfortunately
+%}
+
+/**
+ * helper service for common uses of nsIClipboard.
+ */
+
+[scriptable, uuid(438307fd-0c68-4d79-922a-f6cc9550cd02)]
+interface nsIClipboardHelper : nsISupports
+{
+  cenum SensitiveData : 8 {
+    NotSensitive = 0,
+    Sensitive = 1,
+  };
+
+  /**
+   * copy string to given clipboard
+   *
+   * @param aString, the string to copy to the clipboard
+   * @param aClipboardID, the ID of the clipboard to copy to
+   *        (eg. kSelectionClipboard -- see nsIClipboard.idl)
+   * @param aSensitive, optional flag to indicate that data is sensitive, like a password.
+   *        That will exclude data from Cloud Clipboard/Clipboard History on Windows.
+   */
+  void copyStringToClipboard(in AString aString, in long aClipboardID,
+                             [optional, default(NotSensitive)] in nsIClipboardHelper_SensitiveData aSensitive);
+
+  /**
+   * copy string to (default) clipboard
+   *
+   * @param aString, the string to copy to the clipboard
+   */
+  void copyString(in AString aString,
+                  [optional, default(NotSensitive)] in nsIClipboardHelper_SensitiveData aSensitive);
+};
diff --git a/widget/nsIClipboardOwner.idl b/widget/nsIClipboardOwner.idl
new file mode 100644
index 0000000000..df9dfd1049
--- /dev/null
+++ b/widget/nsIClipboardOwner.idl
@@ -0,0 +1,29 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+#include "nsISupports.idl"
+#include "nsITransferable.idl"
+
+
+[scriptable, uuid(5A31C7A1-E122-11d2-9A57-000064657374)]
+interface nsIClipboardOwner : nsISupports
+{
+   /**
+    * Notifies the owner of the clipboard transferable that the
+    * transferable is being removed from the clipboard
+    *
+    * @param  aTransferable The transferable
+    * @result NS_Ok if no errors
+    */
+
+    void LosingOwnership ( in nsITransferable aTransferable ) ;
+};
+
+
+%{ C++
+
+%}
diff --git a/widget/nsIColorPicker.idl b/widget/nsIColorPicker.idl
new file mode 100644
index 0000000000..aa24bf73cc
--- /dev/null
+++ b/widget/nsIColorPicker.idl
@@ -0,0 +1,72 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface mozIDOMWindowProxy;
+
+/**
+ * nsIColorPicker is representing colors as strings because the internal
+ * representation will depend on the underlying backend.
+ * The format of the colors taken in input and returned will always follow the
+ * format of the <input type='color'> value as described in the HTML
+ * specifications.
+ */
+
+[scriptable, uuid(d2ce78d1-40b5-49d1-b66d-5801fcb9a385)]
+interface nsIColorPickerShownCallback : nsISupports
+{
+ /**
+  * Callback called when the color picker requests a color update.
+  * This callback can not be called after done() was called.
+  * When this callback is used, the consumer can assume that the color value has
+  * changed.
+  *
+  * @param  color  The new selected color value following the format specifed on
+  *                top of this file.
+  */
+ void update(in AString color);
+
+ /**
+  * Callback called when the color picker is dismissed.
+  * When this callback is used, the color might have changed or could stay the
+  * same.
+  * If the color has not changed, the color parameter will be the empty string.
+  *
+  * @param  color  The new selected color value following the format specifed on
+  *                top of this file or the empty string.
+  */
+  void done(in AString color);
+};
+
+[scriptable, uuid(de229d37-a8a6-46f1-969a-0c1de33d0ad7)]
+interface nsIColorPicker : nsISupports
+{
+ /**
+  * Initialize the color picker widget. The color picker will not be shown until
+  * open() is called.
+  * If the backend doesn't support setting a title to the native color picker
+  * widget, the title parameter might be ignored.
+  * If the initialColor parameter does not follow the format specified on top of
+  * this file, the behavior will be unspecified. The initialColor could be the
+  * one used by the underlying backend or an arbitrary one. The backend could
+  * also assert.
+  *
+  * @param      parent       nsIDOMWindow parent. This dialog will be dependent
+  *                          on this parent. parent must be non-null.
+  * @param      title        The title for the color picker widget.
+  * @param      initialColor The color to show when the widget is opened. The
+  *                          parameter has to follow the format specified on top
+  *                          of this file.
+  */
+  void init(in mozIDOMWindowProxy parent, in AString title, in AString initialColor, in Array<AString> defaultColors);
+
+ /**
+  * Opens the color dialog asynchrounously.
+  * The results are provided via the callback object.
+  */
+  void open(in nsIColorPickerShownCallback aColorPickerShownCallback);
+};
diff --git a/widget/nsIDeviceContextSpec.cpp b/widget/nsIDeviceContextSpec.cpp
new file mode 100644
index 0000000000..5ab442415d
--- /dev/null
+++ b/widget/nsIDeviceContextSpec.cpp
@@ -0,0 +1,87 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIDeviceContextSpec.h"
+
+#include "gfxPoint.h"
+#include "mozilla/gfx/PrintPromise.h"
+#include "nsError.h"
+#include "nsIPrintSettings.h"
+
+#include "mozilla/Components.h"
+#include "mozilla/TaskQueue.h"
+
+using mozilla::MakeRefPtr;
+using mozilla::gfx::PrintEndDocumentPromise;
+
+// We have some platform specific code here rather than in the appropriate
+// nsIDeviceContextSpec subclass. We structure the code this way so that
+// nsIDeviceContextSpecProxy gets the correct behavior without us having to
+// instantiate a platform specific nsIDeviceContextSpec subclass in content
+// processes. That is necessary for sandboxing.
+
+float nsIDeviceContextSpec::GetPrintingScale() {
+#ifdef XP_WIN
+  if (mPrintSettings->GetOutputFormat() != nsIPrintSettings::kOutputFormatPDF
+#  ifdef MOZ_ENABLE_SKIA_PDF
+      && !mPrintViaSkPDF
+#  endif
+  ) {
+    // The print settings will have the resolution stored from the real device.
+    int32_t resolution;
+    mPrintSettings->GetResolution(&resolution);
+    return float(resolution) / GetDPI();
+  }
+#endif
+
+  return 72.0f / GetDPI();
+}
+
+gfxPoint nsIDeviceContextSpec::GetPrintingTranslate() {
+#ifdef XP_WIN
+  // The underlying surface on windows is the size of the printable region. When
+  // the region is smaller than the actual paper size the (0, 0) coordinate
+  // refers top-left of that unwritable region. To instead have (0, 0) become
+  // the top-left of the actual paper, translate it's coordinate system by the
+  // unprintable region's width.
+  double marginTop, marginLeft;
+  mPrintSettings->GetUnwriteableMarginTop(&marginTop);
+  mPrintSettings->GetUnwriteableMarginLeft(&marginLeft);
+  int32_t resolution;
+  mPrintSettings->GetResolution(&resolution);
+  return gfxPoint(-marginLeft * resolution, -marginTop * resolution);
+#else
+  return gfxPoint(0, 0);
+#endif
+}
+
+RefPtr<PrintEndDocumentPromise>
+nsIDeviceContextSpec::EndDocumentPromiseFromResult(nsresult aResult,
+                                                   const char* aSite) {
+  return NS_SUCCEEDED(aResult)
+             ? PrintEndDocumentPromise::CreateAndResolve(true, aSite)
+             : PrintEndDocumentPromise::CreateAndReject(aResult, aSite);
+}
+
+RefPtr<PrintEndDocumentPromise> nsIDeviceContextSpec::EndDocumentAsync(
+    const char* aCallSite, AsyncEndDocumentFunction aFunction) {
+  auto promise =
+      MakeRefPtr<PrintEndDocumentPromise::Private>("PrintEndDocumentPromise");
+
+  NS_DispatchBackgroundTask(
+      NS_NewRunnableFunction(
+          "EndDocumentAsync",
+          [promise, function = std::move(aFunction)]() mutable {
+            const auto result = function();
+            if (NS_SUCCEEDED(result)) {
+              promise->Resolve(true, __func__);
+            } else {
+              promise->Reject(result, __func__);
+            }
+          }),
+      NS_DISPATCH_EVENT_MAY_BLOCK);
+
+  return promise;
+}
diff --git a/widget/nsIDeviceContextSpec.h b/widget/nsIDeviceContextSpec.h
new file mode 100644
index 0000000000..6afe4ea850
--- /dev/null
+++ b/widget/nsIDeviceContextSpec.h
@@ -0,0 +1,111 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsIDeviceContextSpec_h___
+#define nsIDeviceContextSpec_h___
+
+#include "gfxPoint.h"
+#include "nsISupports.h"
+#include "mozilla/StaticPrefs_print.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/gfx/PrintPromise.h"
+#include "mozilla/MoveOnlyFunction.h"
+
+class nsIWidget;
+class nsIPrintSettings;
+
+namespace mozilla {
+namespace gfx {
+class DrawEventRecorder;
+class PrintTarget;
+}  // namespace gfx
+}  // namespace mozilla
+
+#define NS_IDEVICE_CONTEXT_SPEC_IID                  \
+  {                                                  \
+    0xf407cfba, 0xbe28, 0x46c9, {                    \
+      0x8a, 0xba, 0x04, 0x2d, 0xae, 0xbb, 0x4f, 0x23 \
+    }                                                \
+  }
+
+class nsIDeviceContextSpec : public nsISupports {
+ public:
+  typedef mozilla::gfx::PrintTarget PrintTarget;
+  using IntSize = mozilla::gfx::IntSize;
+
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_IDEVICE_CONTEXT_SPEC_IID)
+
+  /**
+   * Initialize the device context spec.
+   * @param aWidget         A widget a dialog can be hosted in
+   * @param aPrintSettings  Print settings for the print operation
+   * @param aIsPrintPreview True if creating Spec for PrintPreview
+   * @return NS_OK or a suitable error code.
+   */
+  NS_IMETHOD Init(nsIPrintSettings* aPrintSettings, bool aIsPrintPreview) = 0;
+
+  virtual already_AddRefed<PrintTarget> MakePrintTarget() = 0;
+
+  /**
+   * If required override to return a recorder to record the print.
+   *
+   * @param aDrawEventRecorder out param for the recorder to use
+   * @return NS_OK or a suitable error code
+   */
+  NS_IMETHOD GetDrawEventRecorder(
+      mozilla::gfx::DrawEventRecorder** aDrawEventRecorder) {
+    MOZ_ASSERT(aDrawEventRecorder);
+    *aDrawEventRecorder = nullptr;
+    return NS_OK;
+  }
+
+  /**
+   * @return DPI for printing.
+   */
+  float GetDPI() { return mozilla::StaticPrefs::print_default_dpi(); }
+
+  /**
+   * @return the printing scale to be applied to the context for printing.
+   */
+  float GetPrintingScale();
+
+  /**
+   * @return the point to translate the context to for printing.
+   */
+  gfxPoint GetPrintingTranslate();
+
+  NS_IMETHOD BeginDocument(const nsAString& aTitle,
+                           const nsAString& aPrintToFileName,
+                           int32_t aStartPage, int32_t aEndPage) = 0;
+
+  virtual RefPtr<mozilla::gfx::PrintEndDocumentPromise> EndDocument() = 0;
+  /**
+   * Note: not all print devices implement mixed page sizing. Internally,
+   * aSizeInPoints gets handed off to a PrintTarget, and most PrintTarget
+   * subclasses will ignore `aSizeInPoints`.
+   */
+  NS_IMETHOD BeginPage(const IntSize& aSizeInPoints) = 0;
+  NS_IMETHOD EndPage() = 0;
+
+ protected:
+  using AsyncEndDocumentFunction = mozilla::MoveOnlyFunction<nsresult()>;
+  static RefPtr<mozilla::gfx::PrintEndDocumentPromise> EndDocumentAsync(
+      const char* aCallSite, AsyncEndDocumentFunction aFunction);
+
+  static RefPtr<mozilla::gfx::PrintEndDocumentPromise>
+  EndDocumentPromiseFromResult(nsresult aResult, const char* aSite);
+
+  nsCOMPtr<nsIPrintSettings> mPrintSettings;
+
+#ifdef MOZ_ENABLE_SKIA_PDF
+  // This variable is independant of nsIPrintSettings::kOutputFormatPDF (i.e.
+  // save-to-PDF). If set to true, then even when we print to a printer we
+  // output and send it PDF.
+  bool mPrintViaSkPDF = false;
+#endif
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsIDeviceContextSpec, NS_IDEVICE_CONTEXT_SPEC_IID)
+#endif
diff --git a/widget/nsIDisplayInfo.idl b/widget/nsIDisplayInfo.idl
new file mode 100644
index 0000000000..69d5064e4e
--- /dev/null
+++ b/widget/nsIDisplayInfo.idl
@@ -0,0 +1,14 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[scriptable, uuid(615bc23d-6346-4b15-9c10-add002f140b6)]
+interface nsIDisplayInfo : nsISupports
+{
+  readonly attribute long id;
+  readonly attribute boolean connected;
+};
diff --git a/widget/nsIDragService.idl b/widget/nsIDragService.idl
new file mode 100644
index 0000000000..a35d3128a8
--- /dev/null
+++ b/widget/nsIDragService.idl
@@ -0,0 +1,213 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIArray.idl"
+#include "nsISupports.idl"
+#include "nsIDragSession.idl"
+#include "nsIContentPolicy.idl"
+
+webidl DragEvent;
+webidl Element;
+webidl Node;
+webidl Selection;
+
+interface nsICookieJarSettings;
+
+%{C++
+#include "mozilla/EventForwards.h"
+
+namespace mozilla {
+namespace dom {
+class ContentParent;
+class DataTransfer;
+class RemoteDragStartData;
+} // namespace dom
+} // namespace mozilla
+%}
+
+[ptr] native ContentParentPtr(mozilla::dom::ContentParent);
+[ptr] native DataTransferPtr(mozilla::dom::DataTransfer);
+[ptr] native RemoteDragStartDataPtr(mozilla::dom::RemoteDragStartData);
+native EventMessage(mozilla::EventMessage);
+
+[scriptable, uuid(ebd6b3a2-af16-43af-a698-3091a087dd62), builtinclass]
+interface nsIDragService : nsISupports
+{
+  const long DRAGDROP_ACTION_NONE = 0;
+  const long DRAGDROP_ACTION_COPY = 1;
+  const long DRAGDROP_ACTION_MOVE = 2;
+  const long DRAGDROP_ACTION_LINK = 4;
+  const long DRAGDROP_ACTION_UNINITIALIZED = 64;
+
+  /**
+    * Starts a modal drag session with an array of transaferables.
+    *
+    * Note: This method is deprecated for non-native code.
+    *
+    * @param  aPrincipal - the triggering principal of the drag, or null if
+    *                      it's from browser chrome or OS
+    * @param aCsp - The csp of the triggering Document
+    * @param  aTransferables - an array of transferables to be dragged
+    * @param  aActionType - specified which of copy/move/link are allowed
+    * @param  aContentPolicyType - the contentPolicyType that will be
+    *           passed to the loadInfo when creating a new channel
+    *           (defaults to TYPE_OTHER)
+    */
+  [can_run_script]
+  void invokeDragSession (in Node aDOMNode,
+                          in nsIPrincipal aPrincipal,
+                          in nsIContentSecurityPolicy aCsp,
+                          in nsICookieJarSettings aCookieJarSettings,
+                          in nsIArray aTransferables,
+                          in unsigned long aActionType,
+                          [optional] in nsContentPolicyType aContentPolicyType);
+
+  /**
+   * Starts a modal drag session using an image. The first four arguments are
+   * the same as invokeDragSession.
+   *
+   * Note: This method is deprecated for non-native code.
+   *
+   * A custom image may be specified using the aImage argument. If this is
+   * supplied, the aImageX and aImageY arguments specify the offset within
+   * the image where the cursor would be positioned. That is, when the image
+   * is drawn, it is offset up and left the amount so that the cursor appears
+   * at that location within the image.
+   *
+   * If aImage is null, aImageX and aImageY are not used and the image is instead
+   * determined from the source node aDOMNode, and the offset calculated so that
+   * the initial location for the image appears in the same screen position as
+   * where the element is located. The node must be within a document.
+   *
+   * Currently, supported images are all DOM nodes. If this is an HTML <image> or
+   * <canvas>, the drag image is taken from the image data. If the element is in
+   * a document, it will be rendered at its displayed size, othewise, it will be
+   * rendered at its real size. For other types of elements, the element is
+   * rendered into an offscreen buffer in the same manner as it is currently
+   * displayed. The document selection is hidden while drawing.
+   *
+   * The aDragEvent must be supplied as the current screen coordinates of the
+   * event are needed to calculate the image location.
+   */
+  [noscript, can_run_script]
+  void invokeDragSessionWithImage(in Node aDOMNode,
+                                  in nsIPrincipal aPrincipal,
+                                  in nsIContentSecurityPolicy aCsp,
+                                  in nsICookieJarSettings aCookieJarSettings,
+                                  in nsIArray aTransferableArray,
+                                  in unsigned long aActionType,
+                                  in Node aImage,
+                                  in long aImageX,
+                                  in long aImageY,
+                                  in DragEvent aDragEvent,
+                                  in DataTransferPtr aDataTransfer);
+
+  /** Start a drag session with the data in aDragStartData from a child process.
+   *  Other arguments are the same as invokeDragSessionWithImage.
+   */
+  [noscript, can_run_script]
+  void invokeDragSessionWithRemoteImage(in Node aDOMNode,
+                                        in nsIPrincipal aPrincipal,
+                                        in nsIContentSecurityPolicy aCsp,
+                                        in nsICookieJarSettings aCookieJarSettings,
+                                        in nsIArray aTransferableArray,
+                                        in unsigned long aActionType,
+                                        in RemoteDragStartDataPtr aDragStartData,
+                                        in DragEvent aDragEvent,
+                                        in DataTransferPtr aDataTransfer);
+
+  /**
+   * Start a modal drag session using the selection as the drag image.
+   * The aDragEvent must be supplied as the current screen coordinates of the
+   * event are needed to calculate the image location.
+   *
+   * Note: This method is deprecated for non-native code.
+   */
+  [can_run_script]
+  void invokeDragSessionWithSelection(in Selection aSelection,
+                                      in nsIPrincipal aPrincipal,
+                                      in nsIContentSecurityPolicy aCsp,
+                                      in nsICookieJarSettings aCookieJarSettings,
+                                      in nsIArray aTransferableArray,
+                                      in unsigned long aActionType,
+                                      in DragEvent aDragEvent,
+                                      in DataTransferPtr aDataTransfer);
+
+  /**
+    * Returns the current Drag Session
+    */
+  nsIDragSession getCurrentSession();
+
+  /**
+    * Tells the Drag Service to start a drag session. This is called when
+    * an external drag occurs
+    */
+  void startDragSession() ;
+
+  /**
+   * Similar to startDragSession(), automated tests may want to start
+   * session for emulating an external drag.  At that time, this should
+   * be used instead of startDragSession().
+   *
+   * @param aAllowedEffect Set default drag action which means allowed effects
+   *                       in the session and every DnD events are initialized
+   *                       with one of specified value.  So, the value can be
+   *                       DRAGDROP_ACTION_NONE, or one or more values of
+   *                       DRAGDROP_ACTION_(MOVE|COPY|LINK).
+   */
+  void startDragSessionForTests(in unsigned long aAllowedEffect);
+
+  /**
+    * Tells the Drag Service to end a drag session. This is called when
+    * an external drag occurs
+    *
+    * If aDoneDrag is true, the drag has finished, otherwise the drag has
+    * just left the window.
+    */
+  [can_run_script]
+  void endDragSession(in boolean aDoneDrag,
+                      [optional] in unsigned long aKeyModifiers);
+
+  /**
+   * Fire a drag event at the source of the drag
+   */
+  [noscript, can_run_script]
+  void fireDragEventAtSource(in EventMessage aEventMessage,
+                             in unsigned long aKeyModifiers);
+
+  /**
+   * Increase/decrease dragging suppress level by one.
+   * If level is greater than one, dragging is disabled.
+   */
+  [can_run_script]
+  void suppress();
+  void unsuppress();
+
+  /**
+    * aX and aY are in LayoutDevice pixels.
+    */
+  [noscript] void dragMoved(in long aX, in long aY);
+
+  [notxpcom, nostdcall] boolean maybeAddChildProcess(in ContentParentPtr aChild);
+  [notxpcom, nostdcall] boolean removeAllChildProcesses();
+
+  /**
+   * Retrun true if nsIDragSession's data is updated.
+   */
+  [notxpcom, nostdcall] boolean mustUpdateDataTransfer(in EventMessage aMessage);
+
+  /**
+   * Called when HTMLEditor maybe deleted the source node from the document.
+   *
+   * @param aEditingHost    The editing host when the editor deletes selection.
+   */
+  [noscript] void maybeEditorDeletedSourceNode(in Element aEditingHost);
+};
+
+
+%{ C++
+
+%}
diff --git a/widget/nsIDragSession.idl b/widget/nsIDragSession.idl
new file mode 100644
index 0000000000..e96e6fc1c7
--- /dev/null
+++ b/widget/nsIDragSession.idl
@@ -0,0 +1,151 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "nsITransferable.idl"
+
+
+
+%{ C++
+#include "nsSize.h"
+%}
+interface nsIContentSecurityPolicy;
+
+native nsSize(nsSize);
+
+webidl DataTransfer;
+webidl WindowContext;
+webidl Node;
+webidl Selection;
+
+[scriptable, builtinclass, uuid(25bce737-73f0-43c7-bc20-c71044a73c5a)]
+interface nsIDragSession : nsISupports
+{
+  /**
+    * Set the current state of the drag, whether it can be dropped or not.
+    * usually the target "frame" sets this so the native system can render the correct feedback
+    */
+  attribute boolean canDrop;
+
+  /**
+   * Indicates if the drop event should be dispatched only to chrome.
+   */
+  attribute boolean onlyChromeDrop;
+
+  /**
+    * Sets the action (copy, move, link, et.c) for the current drag
+    */
+  attribute unsigned long dragAction;
+
+  /**
+    * Get the number of items that were dropped
+    */
+  readonly attribute unsigned long numDropItems;
+
+  /**
+    * The window context where the drag was started, which will be null if the
+    * drag originated outside the application. Useful for determining if a drop
+    * originated in the same window context.
+    */
+  [infallible]
+  attribute WindowContext sourceWindowContext;
+
+  /**
+    * The top-level window context where the drag was started, which will be
+    * null if the drag originated outside the application. Useful for
+    * determining if a drop originated in the same top-level window context.
+    */
+  [infallible]
+  attribute WindowContext sourceTopWindowContext;
+
+  /**
+    * The dom node that was originally dragged to start the session, which will be null if the
+    * drag originated outside the application.
+    */
+  readonly attribute Node sourceNode;
+
+  /**
+   * Replace source node and selection with new ones.
+   * If sourceNode is a native anonymous node, it may be replaced at reframing.
+   * If sourceNode is disconnected from the document, we cannot dispatch
+   * `dragend` event properly.
+   * When this is called, sourceNode or aNewSourceNode should be a native
+   * anonymous node.
+   */
+  [notxpcom, nostdcall] void updateSource(in Node aNewSourceNode,
+                                          in Selection aNewSelection);
+
+  /**
+   * the triggering principal.  This may be different than sourceNode's
+   * principal when sourceNode is xul:browser and the drag is
+   * triggered in a browsing context inside it.
+   */
+  attribute nsIPrincipal triggeringPrincipal;
+
+  /**
+   * the triggering csp.  This may be different than sourceNode's
+   * csp when sourceNode is xul:browser and the drag is
+   * triggered in a browsing context inside it.
+   */
+  attribute nsIContentSecurityPolicy csp;
+
+  /**
+   * The data transfer object for the current drag.
+   */
+  [binaryname(DataTransferXPCOM)]
+  attribute DataTransfer dataTransfer;
+  [notxpcom, nostdcall] DataTransfer getDataTransfer();
+  [notxpcom, nostdcall] void setDataTransfer(in DataTransfer aDataTransfer);
+
+  /**
+    * Get data from a Drag&Drop. Can be called while the drag is in process
+    * or after the drop has completed.
+    *
+    * @param  aTransferable the transferable for the data to be put into
+    * @param  aItemIndex which of multiple drag items, zero-based
+    */
+  void getData ( in nsITransferable aTransferable, in unsigned long aItemIndex ) ;
+
+   /**
+    * Check to set if any of the native data on the clipboard matches this data flavor
+    */
+  boolean isDataFlavorSupported ( in string aDataFlavor ) ;
+
+  void userCancelled();
+
+  void dragEventDispatchedToChildProcess();
+
+  // Called when nsIDragSession implementation should update the UI for the
+  // drag-and-drop based on the data got from the child process in response to
+  // NS_DRAGDROP_OVER sent from parent process to child process.
+  void updateDragEffect();
+
+  // Change the drag image, using similar arguments as
+  // nsIDragService::InvokeDragSessionWithImage.
+  void updateDragImage(in Node aImage, in long aImageX, in long aImageY);
+
+  /**
+   * Returns effects allowed at starting the session for tests.
+   */
+  [notxpcom, nostdcall] unsigned long getEffectAllowedForTests();
+
+  /**
+   * Returns true if current session was started with synthesized drag start.
+   */
+  [notxpcom, nostdcall] bool isSynthesizedForTests();
+
+  /**
+   * Sets drag end point of synthesized session when the test does not dispatch
+   * "drop" event.
+   */
+  void setDragEndPointForTests(in long aScreenX, in long aScreenY);
+
+  /**
+   * Returns true if the session is for dragging text in a text in text control
+   * element.
+   */
+  [notxpcom, nostdcall] bool isDraggingTextInTextControl();
+};
diff --git a/widget/nsIFilePicker.idl b/widget/nsIFilePicker.idl
new file mode 100644
index 0000000000..e9bdedfd42
--- /dev/null
+++ b/widget/nsIFilePicker.idl
@@ -0,0 +1,255 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIFile;
+interface nsIURI;
+interface mozIDOMWindowProxy;
+interface nsISimpleEnumerator;
+webidl BrowsingContext;
+
+// Declared in this file, below.
+interface nsIFilePickerShownCallback;
+
+[scriptable, uuid(9285b984-02d3-46b4-9514-7da8c471a747)]
+interface nsIFilePicker : nsISupports
+{
+  cenum Mode: 16 {
+    modeOpen         = 0,                        // Load a file or directory
+    modeSave         = 1,                        // Save a file or directory
+    modeGetFolder    = 2,                        // Select a folder/directory
+    modeOpenMultiple = 3,                        // Load multiple files
+  };
+
+  cenum ResultCode: 16 {
+    returnOK        = 0,                        // User hit Ok, process selection
+    returnCancel    = 1,                        // User hit cancel, ignore selection
+    returnReplace   = 2,                        // User acknowledged file already exists so ok to replace, process selection
+  };
+
+  const long filterAll        = 0x001;          // *.*
+  const long filterHTML       = 0x002;          // *.html; *.htm
+  const long filterText       = 0x004;          // *.txt
+  const long filterImages     = 0x008;          // *.jpe; *.jpg; *.jpeg; *.gif;
+                                                // *.png; *.bmp; *.ico; *.svg;
+                                                // *.svgz; *.tif; *.tiff; *.ai;
+                                                // *.drw; *.pct; *.psp; *.xcf;
+                                                // *.psd; *.raw; *.webp; *.heic
+  const long filterXML        = 0x010;          // *.xml
+  const long filterXUL        = 0x020;          // *.xul
+  const long filterApps       = 0x040;          // Applications (per-platform implementation)
+  const long filterAllowURLs  = 0x080;          // Allow URLs
+  const long filterAudio      = 0x100;          // *.aac; *.aif; *.flac; *.iff;
+                                                // *.m4a; *.m4b; *.mid; *.midi;
+                                                // *.mp3; *.mpa; *.mpc; *.oga;
+                                                // *.ogg; *.ra; *.ram; *.snd;
+                                                // *.wav; *.wma
+  const long filterVideo      = 0x200;          // *.avi; *.divx; *.flv; *.m4v;
+                                                // *.mkv; *.mov; *.mp4; *.mpeg;
+                                                // *.mpg; *.ogm; *.ogv; *.ogx;
+                                                // *.rm; *.rmvb; *.smil; *.webm;
+                                                // *.wmv; *.xvid
+  const long filterPDF        = 0x400;          // *.pdf;
+
+  cenum CaptureTarget: 8 {
+    captureNone     = 0,                        // No capture target specified.
+    captureDefault  = 1,                        // Missing/invalid value default.
+    captureUser     = 2,                        // "user" capture target specified.
+    captureEnv      = 3,                        // "environment" capture target specified.
+  };
+
+ /**
+  * Initialize the file picker widget.  The file picker is not valid until this
+  * method is called.
+  *
+  * @param      parent   mozIDOMWindow parent.  This dialog will be dependent
+  *                      on this parent. parent must be non-null.
+  * @param      title    The title for the file widget
+  * @param      mode     load, save, or get folder
+  * @param      browsingContext [optional]
+  *             The context in which the file picker is being shown. This is
+  *             used for content analysis and can be omitted if chrome is
+  *             showing the file picker.
+  */
+  void init(in mozIDOMWindowProxy parent,
+            in AString title,
+            in nsIFilePicker_Mode mode,
+            [optional] in BrowsingContext browsingContext);
+
+  /**
+   * Returns a Promise that resolves to true if the passed nsIFilePicker mode
+   * is supported on the current platform, and false otherwise. The Promise may
+   * reject if something unexpected occurs while trying to determine if the mode
+   * is supported.
+   *
+   * @param mode
+   * @return Promise<boolean>
+   */
+  [implicit_jscontext]
+  Promise isModeSupported(in nsIFilePicker_Mode mode);
+
+ /**
+  * Append to the  filter list with things from the predefined list
+  *
+  * @param      filters  mask of filters i.e. (filterAll | filterHTML)
+  *
+  */
+  void appendFilters(in long filterMask);
+
+ /**
+  * Add a filter
+  *
+  * @param      title    name of the filter
+  * @param      filter   extensions to filter -- semicolon and space separated
+  *
+  */
+  void appendFilter(in AString title,
+                    in AString filter);
+
+  /**
+   * Add a raw filter (eg, add a MIME type without transforming it to a list of
+   * extensions).
+   *
+   * @param     filter   a filter taken directly from the accept attribute
+   *                     without processing
+   *
+   */
+  void appendRawFilter(in AString filter);
+
+ /**
+  * The filename that should be suggested to the user as a default. This should
+  * include the extension.
+  *
+  * @throws NS_ERROR_FAILURE on attempts to get
+  */
+  attribute AString defaultString;
+
+ /**
+  * The extension that should be associated with files of the type we
+  * want to work with.  On some platforms, this extension will be
+  * automatically appended to filenames the user enters, if needed.
+  */
+  attribute AString defaultExtension;
+
+ /**
+  * The filter which is currently selected in the File Picker dialog
+  *
+  * @return Returns the index (0 based) of the selected filter in the filter list.
+  */
+  attribute long filterIndex;
+
+ /**
+  * Set the directory that the file open/save dialog initially displays
+  * Note that, if displaySpecialDirectory has been already set, this value will
+  * be ignored.
+  *
+  * @param      displayDirectory  the name of the directory
+  *
+  */
+  attribute nsIFile displayDirectory;
+
+ /**
+  * Set the directory that the file open/save dialog initially displays using
+  * one of the special name as such as 'Desk', 'TmpD', and so on.
+  * Note that, if displayDirectory has been already set, this value will be
+  * ignored.
+  *
+  * @param      displaySpecialDirectory  the name of the special directory
+  *
+  */
+  attribute AString displaySpecialDirectory;
+
+
+ /**
+  * Get the nsIFile for the file or directory. A different file object
+  * may be returned by each invocation.
+  *
+  * @return Returns the file currently selected
+  */
+  readonly attribute nsIFile file;
+
+ /**
+  * Get the nsIURI for the file or directory.
+  *
+  * @return Returns the file currently selected
+  */
+  readonly attribute nsIURI fileURL;
+
+ /**
+  * Get the enumerator for the selected files
+  * only works in the modeOpenMultiple mode
+  *
+  * @return Returns the files currently selected
+  */
+  readonly attribute nsISimpleEnumerator files;
+
+ /**
+  * Get the DOM File or the DOM Directory
+  *
+  * @return Returns the file or directory currently selected DOM object.
+  */
+  readonly attribute nsISupports domFileOrDirectory;
+
+ /**
+  * Get the enumerator for the selected files or directories
+  * only works in the modeOpenMultiple mode
+  *
+  * @return Returns the files/directories currently selected as DOM object.
+  */
+  readonly attribute nsISimpleEnumerator domFileOrDirectoryEnumerator;
+
+ /**
+  * Controls whether the chosen file(s) should be added to the system's recent
+  * documents list. This attribute will be ignored if the system has no "Recent
+  * Docs" concept, or if the application is in private browsing mode (in which
+  * case the file will not be added). Defaults to true.
+  */
+  attribute boolean addToRecentDocs;
+
+ /**
+  * Opens the file dialog asynchrounously.
+  * The passed in object's done method will be called upon completion.
+  */
+  void open(in nsIFilePickerShownCallback aFilePickerShownCallback);
+
+ /**
+  * Closes the file dialog if open.
+  */
+  void close();
+
+ /**
+  * The picker's mode, as set by the 'mode' argument passed to init()
+  * (one of the modeOpen et. al. constants specified above).
+  */
+  readonly attribute nsIFilePicker_Mode mode;
+
+  /**
+   * If set to non-empty string, the nsIFilePicker implementation
+   * may use okButtonLabel as the label for the button the user uses to accept
+   * file selection.
+   */
+  attribute AString okButtonLabel;
+
+  /**
+   * Implementation of HTMLInputElement's `capture` property.
+   *
+   * Not used by Firefox Desktop.
+   */
+  attribute nsIFilePicker_CaptureTarget capture;
+};
+
+[scriptable, function, uuid(0d79adad-b244-49A5-9997-2a8cad93fc44)]
+interface nsIFilePickerShownCallback : nsISupports
+{
+ /**
+  * Callback which is called when a filepicker is shown and a result
+  * is returned.
+  *
+  * @param aResult One of returnOK, returnCancel, or returnReplace
+  */
+  void done(in nsIFilePicker_ResultCode aResult);
+};
diff --git a/widget/nsIFormatConverter.idl b/widget/nsIFormatConverter.idl
new file mode 100644
index 0000000000..0d72f49d2a
--- /dev/null
+++ b/widget/nsIFormatConverter.idl
@@ -0,0 +1,50 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[scriptable, uuid(948A0023-E3A7-11d2-96CF-0060B0FB9956)]
+interface nsIFormatConverter : nsISupports
+{
+  /**
+    * Get the list of the "input" data flavors (mime types as nsISupportsCString),
+    * in otherwords, the flavors that this converter can convert "from" (the
+    * incoming data to the converter).
+    */
+  Array<ACString> getInputDataFlavors ( ) ;
+
+  /**
+    * Get the list of the "output" data flavors (mime types as nsISupportsCString),
+    * in otherwords, the flavors that this converter can convert "to" (the
+    * outgoing data to the converter).
+    *
+    * @param  aDataFlavorList fills list with supported flavors
+    */
+  Array<ACString> getOutputDataFlavors ( ) ;
+
+  /**
+    * Determines whether a conversion from one flavor to another is supported
+    *
+    * @param  aFromFormatConverter flavor to convert from
+    * @param  aFromFormatConverter flavor to convert to
+    */
+  boolean canConvert ( in string aFromDataFlavor, in string aToDataFlavor ) ;
+
+  /**
+    * Converts from one flavor to another.
+    *
+    * @param  aFromFormatConverter flavor to convert from
+    * @param  aFromFormatConverter flavor to convert to (destination own the memory)
+    * @returns returns NS_OK if it was converted
+    */
+  void convert ( in string aFromDataFlavor, in nsISupports aFromData,
+                   in string aToDataFlavor, out nsISupports aToData ) ;
+
+};
+
+
+%{ C++
+
+%}
diff --git a/widget/nsIGfxInfo.idl b/widget/nsIGfxInfo.idl
new file mode 100644
index 0000000000..4f4f0b7e1e
--- /dev/null
+++ b/widget/nsIGfxInfo.idl
@@ -0,0 +1,366 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+/* NOTE: this interface is completely undesigned, not stable and likely to change */
+[scriptable, builtinclass, uuid(1accd618-4c80-4703-9d29-ecf257d397c8)]
+interface nsIGfxInfo : nsISupports
+{
+  /*
+   * These are win32-specific
+   */
+  readonly attribute boolean D2DEnabled;
+  readonly attribute boolean DWriteEnabled;
+  readonly attribute boolean EmbeddedInFirefoxReality;
+  readonly attribute AString AzureCanvasBackend;
+  readonly attribute AString AzureContentBackend;
+  readonly attribute boolean usingGPUProcess;
+  readonly attribute boolean hasBattery;
+  readonly attribute AString DWriteVersion;
+  readonly attribute AString cleartypeParameters;
+
+  /*
+   * These are non-Android linux-specific
+   */
+  readonly attribute AString windowProtocol;
+  readonly attribute AString testType;
+
+  /*
+   * These are valid across all platforms.
+   */
+  readonly attribute AString ContentBackend;
+  readonly attribute boolean isHeadless;
+  readonly attribute unsigned long TargetFrameRate;
+  readonly attribute ACString CodecSupportInfo;
+
+  // XXX: Switch to a list of devices, rather than explicitly numbering them.
+
+  // Present on all platforms, but only useful on Android
+  cenum FontVisibilityDeviceDetermination : 8 {
+    Unassigned = 0,
+    Unknown_Platform = 1,
+    Windows_Platform = 2,
+    MacOS_Platform = 3,
+    Android_Unknown_Release_Version = 4,
+    Android_Unknown_Peloton = 5,
+    Android_Unknown_vbox = 6,
+    Android_Unknown_mitv = 7,
+    Android_Chromebook = 8,
+    Android_Amazon = 9,
+    Android_sub_9 = 10,
+    Android_9_11 = 11,
+    Android_12_plus = 12,
+    Linux_Unknown = 13,
+    Linux_Ubuntu_any = 14,
+    Linux_Ubuntu_20 = 15,
+    Linux_Ubuntu_22 = 16,
+    Linux_Fedora_any = 17,
+    Linux_Fedora_38 = 18,
+    Linux_Fedora_39 = 19
+  };
+  readonly attribute nsIGfxInfo_FontVisibilityDeviceDetermination fontVisibilityDetermination;
+  readonly attribute AString fontVisibilityDeterminationStr;
+
+  /**
+   * The name of the display adapter.
+   */
+  readonly attribute AString adapterDescription;
+  readonly attribute AString adapterDescription2;
+
+  readonly attribute AString adapterDriver;
+  readonly attribute AString adapterDriver2;
+
+  /* These types are inspired by DXGI_ADAPTER_DESC */
+  readonly attribute AString adapterVendorID;
+  readonly attribute AString adapterVendorID2;
+
+  readonly attribute AString adapterDeviceID;
+  readonly attribute AString adapterDeviceID2;
+
+  readonly attribute AString adapterSubsysID;
+  readonly attribute AString adapterSubsysID2;
+
+  /**
+   * The amount of RAM in MB in the display adapter.
+   */
+  readonly attribute unsigned long adapterRAM;
+  readonly attribute unsigned long adapterRAM2;
+
+  readonly attribute AString adapterDriverVendor;
+  readonly attribute AString adapterDriverVendor2;
+
+  readonly attribute AString adapterDriverVersion;
+  readonly attribute AString adapterDriverVersion2;
+
+  readonly attribute AString adapterDriverDate;
+  readonly attribute AString adapterDriverDate2;
+
+  readonly attribute boolean isGPU2Active;
+
+  readonly attribute ACString drmRenderDevice;
+
+  /**
+   * Returns an array of objects describing each monitor. Guaranteed properties
+   * are "screenWidth" and "screenHeight". This is only implemented on Desktop.
+   *
+   * Windows additionally supplies "refreshRate" and "pseudoDisplay".
+   *
+   * OS X additionally supplies "scale".
+   */
+  [implicit_jscontext]
+  jsval getMonitors();
+
+  Array<ACString> getFailures(out Array<long> indices);
+
+  [noscript, notxpcom] void logFailure(in ACString failure);
+  /*
+   * A set of constants for features that we can ask this GfxInfo object
+   * about via GetFeatureStatus
+   */
+  /* Don't assign any value <= 0 */
+  /* Values must be contiguous */
+  /* Whether Direct2D is supported for content rendering. */
+  const long FEATURE_DIRECT2D = 1;
+  /* Whether Direct3D 9 is supported for layers. */
+  const long FEATURE_DIRECT3D_9_LAYERS = 2;
+  /* Whether Direct3D 10.0 is supported for layers. */
+  const long FEATURE_DIRECT3D_10_LAYERS = 3;
+  /* Whether Direct3D 10.1 is supported for layers. */
+  const long FEATURE_DIRECT3D_10_1_LAYERS = 4;
+  /* Whether OpenGL is supported for layers */
+  const long FEATURE_OPENGL_LAYERS = 5;
+  /* Whether WebGL is supported via OpenGL. */
+  const long FEATURE_WEBGL_OPENGL = 6;
+  /* Whether WebGL is supported via ANGLE (D3D9 -- does not check for the presence of ANGLE libs). */
+  const long FEATURE_WEBGL_ANGLE = 7;
+  /* (Unused) Whether WebGL antialiasing is supported. */
+  const long UNUSED_FEATURE_WEBGL_MSAA = 8;
+  /* Whether Stagefright is supported, starting in 17. */
+  const long FEATURE_STAGEFRIGHT = 9;
+  /* Whether Webrtc Hardware H.264 acceleration is supported, starting in 71. */
+  const long FEATURE_WEBRTC_HW_ACCELERATION_H264 = 10;
+  /* Whether Direct3D 11 is supported for layers, starting in 32. */
+  const long FEATURE_DIRECT3D_11_LAYERS = 11;
+  /* Whether hardware accelerated video decoding is supported, starting in 36. */
+  const long FEATURE_HARDWARE_VIDEO_DECODING = 12;
+  /* Whether Direct3D 11 is supported for ANGLE, starting in 38. */
+  const long FEATURE_DIRECT3D_11_ANGLE = 13;
+  /* Whether Webrtc Hardware acceleration is supported, starting in 42. */
+  const long FEATURE_WEBRTC_HW_ACCELERATION_ENCODE = 14;
+  /* Whether Webrtc Hardware acceleration is supported, starting in 42. */
+  const long FEATURE_WEBRTC_HW_ACCELERATION_DECODE = 15;
+  /* Whether Canvas acceleration is supported, starting in 45 */
+  const long FEATURE_CANVAS2D_ACCELERATION = 16;
+  /* Whether hardware VP8 decoding is supported, starting in 48; not for downloadable blocking. */
+  const long FEATURE_VP8_HW_DECODE = 17;
+  /* Whether hardware VP9 decoding is supported, starting in 48; not for downloadable blocking. */
+  const long FEATURE_VP9_HW_DECODE = 18;
+  /* Whether NV_dx_interop2 is supported, starting in 50; downloadable blocking in 58. */
+  const long FEATURE_DX_INTEROP2 = 19;
+  /* Whether the GPU process is supported, starting in 52; downloadable blocking in 58. */
+  const long FEATURE_GPU_PROCESS = 20;
+  /* Whether the WebGL2 is supported, starting in 54 */
+  const long FEATURE_WEBGL2 = 21;
+  /* Whether D3D11 keyed mutex is supported, starting in 56 */
+  const long FEATURE_D3D11_KEYED_MUTEX = 22;
+  /* Whether WebRender is supported, starting in 62 */
+  const long FEATURE_WEBRENDER = 23;
+  /* Whether WebRender is supported, starting in 62 */
+  const long FEATURE_DX_NV12 = 24;
+  const long FEATURE_DX_P010 = 25;
+  const long FEATURE_DX_P016 = 26;
+  /* Whether OpenGL swizzle configuration of texture units is supported, starting in 70 */
+  const long FEATURE_GL_SWIZZLE = 27;
+  /* Whether WebRender native compositor is supported, starting in 73 */
+  const long FEATURE_WEBRENDER_COMPOSITOR = 28;
+  /* Whether WebRender can use scissored clears for cached surfaces, staring in 79 */
+  const long FEATURE_WEBRENDER_SCISSORED_CACHE_CLEARS = 29;
+  /* Support webgl.out-of-process: true (starting in 83) */
+  const long FEATURE_ALLOW_WEBGL_OUT_OF_PROCESS = 30;
+  /* Is OpenGL threadsafe (starting in 83) */
+  const long FEATURE_THREADSAFE_GL = 31;
+  /* Whether webrender uses pre-optimized shaders, starting in 87. */
+  const long FEATURE_WEBRENDER_OPTIMIZED_SHADERS = 32;
+  /* Whether we prefer EGL over GLX with X11, starting in 88. */
+  const long FEATURE_X11_EGL = 33;
+  /* Whether DMABUF is supported, starting in 88. */
+  const long FEATURE_DMABUF = 34;
+  /* Whether webrender caches shader program binaries to disk, starting in 89. */
+  const long FEATURE_WEBRENDER_SHADER_CACHE = 35;
+  /* Whether partial present is allowed with WebRender, starting in 98. */
+  const long FEATURE_WEBRENDER_PARTIAL_PRESENT = 36;
+  /* Whether WebGPU is supported, starting in 100. */
+  const long FEATURE_WEBGPU = 37;
+  /* Whether video overlay of hardware decoded video is supported, starting in 100. */
+  const long FEATURE_VIDEO_OVERLAY = 38;
+  /* Whether hardware decoded video zero copy is supported, starting in 101. */
+  const long FEATURE_HW_DECODED_VIDEO_ZERO_COPY = 39;
+  /* Whether DMABUF export is supported, starting in 103. */
+  const long FEATURE_DMABUF_SURFACE_EXPORT = 40;
+  /* Whether reuse decoder device is supported, starting in 104. */
+  const long FEATURE_REUSE_DECODER_DEVICE = 41;
+  /* Whether to allow backdrop filter, starting in 105. */
+  const long FEATURE_BACKDROP_FILTER = 42;
+  /* Whether to use Accelerated Canvas2D, starting in 110. */
+  const long FEATURE_ACCELERATED_CANVAS2D = 43;
+  /* Whether hardware H264 decoding is supported, starting in 114; not for downloadable blocking. */
+  const long FEATURE_H264_HW_DECODE = 44;
+  /* Whether hardware AV1 decoding is supported, starting in 114; not for downloadable blocking. */
+  const long FEATURE_AV1_HW_DECODE = 45;
+  /* Whether video overlay of software decoded video is supported, starting in 116. */
+  const long FEATURE_VIDEO_SOFTWARE_OVERLAY = 46;
+  /* Whether WebGL is allowed to use hardware rendering, otherwise software fallbacks. */
+  const long FEATURE_WEBGL_USE_HARDWARE = 47;
+  /* the maximum feature value. */
+  const long FEATURE_MAX_VALUE = FEATURE_WEBGL_USE_HARDWARE;
+
+  /*
+   * A set of return values from GetFeatureStatus
+   */
+
+  /* The driver is safe to the best of our knowledge */
+  const long FEATURE_STATUS_OK = 1;
+  /* We don't know the status of the feature yet. The analysis probably hasn't finished yet. */
+  const long FEATURE_STATUS_UNKNOWN = 2;
+  /* This feature is blocked on this driver version. Updating driver will typically unblock it. */
+  const long FEATURE_BLOCKED_DRIVER_VERSION = 3;
+  /* This feature is blocked on this device, regardless of driver version.
+   * Typically means we hit too many driver crashes without a good reason to hope for them to
+   * get fixed soon. */
+  const long FEATURE_BLOCKED_DEVICE = 4;
+  /* This feature is available and can be used, but is not suggested (e.g. shouldn't be used by default */
+  const long FEATURE_DISCOURAGED = 5;
+  /* This feature is blocked on this OS version. */
+  const long FEATURE_BLOCKED_OS_VERSION = 6;
+  /* This feature is blocked because of mismatched driver versions. */
+  const long FEATURE_BLOCKED_MISMATCHED_VERSION = 7;
+  /* This feature is blocked due to not being on the allowlist. */
+  const long FEATURE_DENIED = 8;
+  /* This feature is safe to be on this device due to the allowlist. */
+  const long FEATURE_ALLOW_ALWAYS = 9;
+  /* This feature is safe to be on this device due to the allowlist, depending on qualified/experiment status. */
+  const long FEATURE_ALLOW_QUALIFIED = 10;
+  /* This feature failed in a startup test, e.g. due to a crashing driver. */
+  const long FEATURE_BLOCKED_PLATFORM_TEST = 11;
+
+  /**
+   * Ask about a feature, and return the status of that feature.
+   * If the feature is not ok then aFailureId will give a unique failure Id
+   * otherwise it will be empty.
+   */
+  long getFeatureStatus(in long aFeature, [optional] out ACString aFailureId);
+
+  /*
+   * Ask about a feature, return the minimum driver version required for it if its status is
+   * FEATURE_BLOCKED_DRIVER_VERSION, otherwise return an empty string.
+   */
+  AString getFeatureSuggestedDriverVersion(in long aFeature);
+
+  // only useful on X11
+  [noscript, notxpcom] void GetData();
+
+  /**
+   * Maximum refresh rate among detected monitors. -1 if unknown. aMixed is set
+   * to true if we know there are multiple displays and they have different
+   * refresh rates, else false. The returned value is in Hz.
+   */
+  [noscript, notxpcom] long GetMaxRefreshRate(out boolean aMixed);
+
+  [implicit_jscontext]
+  jsval getInfo();
+
+  // Return an object describing all features that have been configured:
+  //
+  //   "features": [
+  //     // For each feature:
+  //     {
+  //       "name": <string>,
+  //       "description": <string>,
+  //       "status": <string>,
+  //       "log": [
+  //          // One or more log entries, the first denotes the default value.
+  //          {
+  //            "type": <string>,    // "base", "user", "env", or "runtime"
+  //            "status": <string>,
+  //            "message": <string>  // Set unless type is "base" and status is "available".
+  //          }
+  //       ]
+  //     }
+  //   ]
+  //   "fallbacks": [
+  //     // For each workaround:
+  //     {
+  //       "name:" <string>,
+  //       "description": <string>,
+  //       "message": <string>
+  //     ]
+  //   }
+  //
+  // When a message is prefixed with a '#', it is a special status code. Status
+  // codes are unique identifiers that can be searched in the codebase to find
+  // which line of code caused the message. Some codes are standardized to
+  // improve about:support messaging:
+  //
+  //   "[CONTEXT_]FEATURE_FAILURE_BUG_<number>"
+  //     CONTEXT is optional and can currently only be "BLOCKLIST".
+  //     <number> refers to a bug number in Bugzilla.
+  //
+  [implicit_jscontext]
+  jsval getFeatureLog();
+
+  // Returns an object containing information about graphics features. It is
+  // intended to be directly included into the Telemetry environment.
+  //
+  //   "layers":
+  //   {
+  //     "compositor": "d3d9", "d3d11", "opengl", "basic", or "none"
+  //                   // ("none" indicates no compositors have been created)
+  //     // Feature is one of "d3d9", "d3d11", "opengl", "basic", or "d2d".
+  //     "<feature>": {
+  //       // Each backend can have one of the following statuses:
+  //       //   "unused"      - This feature has not been requested.
+  //       //   "unavailable" - OS version or restriction prevents use.
+  //       //   "blocked"     - An internal condition (such as safe mode) prevents use.
+  //       //   "blocklisted" - Blocked due to a blocklist restriction.
+  //       //   "denied"      - Blocked due to allowlist restrictions.
+  //       //   "disabled"    - User explicitly disabled this default feature.
+  //       //   "failed"      - Feature failed to initialize.
+  //       //   "available"   - User has this feature available by default.
+  //       "status": "<status>",
+  //       "version": "<version>",
+  //       "warp": true|false,           // D3D11 only.
+  //       "textureSharing": true|false, // D3D11 only.
+  //     }
+  //   }
+  [implicit_jscontext]
+  jsval getFeatures();
+
+  // Returns an array listing any active crash guards.
+  //
+  //   [
+  //     {
+  //       // Type is one of "d3d11layers", or "glcontext".
+  //       "type":        "<identifier>",
+  //
+  //       // Preference that must be deleted/reset to retrigger the guard.
+  //       "prefName":    "<preference>",
+  //     }
+  //   ]
+  [implicit_jscontext]
+  jsval getActiveCrashGuards();
+
+  // Forces the GPU process to start or shutdown. This is intended only for
+  // xpcshell-tests.
+  boolean controlGPUProcessForXPCShell(in boolean aEnable);
+
+  // Kills the GPU process cleanly, without generating a crash dump.
+  // This is intended only for use by tests.
+  void killGPUProcessForTests();
+
+  // Causes the GPU process to crash. This is intended only for use by tests.
+  void crashGPUProcessForTests();
+};
diff --git a/widget/nsIGfxInfoDebug.idl b/widget/nsIGfxInfoDebug.idl
new file mode 100644
index 0000000000..894dfa97ae
--- /dev/null
+++ b/widget/nsIGfxInfoDebug.idl
@@ -0,0 +1,19 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+/* NOTE: this interface is only implemented in debug builds */
+
+[scriptable, uuid(ca7b0bc7-c67c-4b79-8270-ed7ba002af08)]
+interface nsIGfxInfoDebug : nsISupports
+{
+  void spoofVendorID(in AString aVendorID);
+  void spoofDeviceID(in AString aDeviceID);
+
+  void spoofDriverVersion(in AString aDriverVersion);
+
+  void spoofOSVersion(in unsigned long aVersion);
+};
diff --git a/widget/nsIGtkTaskbarProgress.idl b/widget/nsIGtkTaskbarProgress.idl
new file mode 100644
index 0000000000..ebefe5e3a1
--- /dev/null
+++ b/widget/nsIGtkTaskbarProgress.idl
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsITaskbarProgress.idl"
+
+interface mozIDOMWindowProxy;
+
+/**
+ * Allow the TaskbarProgress instance to set a new target window.
+ */
+
+[scriptable, uuid(39f6fc5a-2386-4bc6-941c-d7479253bc3f)]
+interface nsIGtkTaskbarProgress : nsITaskbarProgress
+{
+  /**
+   * Sets the window that is considered primary for purposes of
+   * setting the XApp progress property.
+   */
+
+  void setPrimaryWindow(in mozIDOMWindowProxy aWindow);
+};
diff --git a/widget/nsIJumpListBuilder.idl b/widget/nsIJumpListBuilder.idl
new file mode 100644
index 0000000000..1b7b93e5e7
--- /dev/null
+++ b/widget/nsIJumpListBuilder.idl
@@ -0,0 +1,119 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+interface nsIURI;
+
+[scriptable, uuid(5769F08D-0303-4E38-8FE6-86B5473022F6)]
+interface nsIJumpListBuilder : nsISupports
+{
+  /**
+   * Returns the local filesystem path for a favicon for a page hosted at
+   * faviconURL if we happen to have written one to disk before. If we have not,
+   * then a background thread retrieves the favicon and will write it to disk
+   * and NS_ERROR_NOT_AVAILABLE will be thrown.
+   *
+   * @param {nsIURI} faviconURL
+   *   The URL for the web page for which we would like a filesystem path for
+   *   the favicon.
+   * @returns {AString}
+   *   The local filesystem path for the favicon if it has been cached before.
+   *   If it has not been cached before, this method will throw
+   *   NS_ERROR_NOT_AVAILABLE.
+   * @throws NS_ERROR_NOT_AVAILABLE
+   *   In the event that the favicon has never been cached to disk before.
+   */
+  AString obtainAndCacheFavicon(in nsIURI faviconURL);
+
+  /**
+   * Returns a Promise that resolves with whether or not the Jump List backend
+   * on the background thread is up and running.
+   *
+   * @returns {Promise<boolean>}
+   *   Resolves to true if the backend is ready to accept
+   *   WindowsJumpListShortcutDescriptions. False, otherwise.
+   * @throws NS_ERROR_FAILURE
+   *   If an attempt to communicate with the background thread fails.
+   */
+  [implicit_jscontext]
+  Promise isAvailable();
+
+  /**
+   * Asks the Windows Jump List API for any items that might have been removed
+   * by the user from the Jump List UI.
+   *
+   * Important: This should be called prior to any attempt to call
+   * `populateJumpList` to ensure that any passed in
+   * WindowsJumpListShortcutDescriptions do not describe items that the user has
+   * just removed. Failing to do so will cause the Promise returned from
+   * `populateJumpList` to reject. This is a constraint of the underlying win32
+   * API. Please see
+   * https://learn.microsoft.com/en-us/windows/win32/api/shobjidl_core/nf-shobjidl_core-icustomdestinationlist-beginlist
+   * for more details.
+   *
+   * @returns {Promise<string[], nsresult>}
+   *   On success, will return an array of strings for URLs of history that
+   *   have been removed by the user via the Windows Jump List. These items will
+   *   also have had their cached favicons removed from the disk off of the
+   *   main thread. On failure, this will reject with the nsresult failure code.
+   * @throws NS_ERROR_FAILURE
+   *   If an attempt to communicate with the background thread fails.
+   */
+  [implicit_jscontext]
+  Promise checkForRemovals();
+
+  /**
+   * Writes a new set of items to the Windows Jump List. This occurs
+   * asynchronously, off of the main thread.
+   *
+   * Important: Callers should first call `checkForRemovals` to remove any
+   * browsing history items that the user chose to remove in the Jump List
+   *  Only then should any WindowsJumpListShortcutDescriptions be created
+   * and passed to this method. Any attempt to add
+   * WindowsJumpListShortcutDescriptions matching items that have been removed
+   * by the user will result in the returned Promise rejecting. This is a
+   * constraint of the underlying win32 API. Please see
+   * https://learn.microsoft.com/en-us/windows/win32/api/shobjidl_core/nf-shobjidl_core-icustomdestinationlist-beginlist
+   * for more details.
+   *
+   * @param {WindowsJumpListShortcutDescription[]} aTaskDescriptions
+   *   0 or more WindowsJumpListShortcutDescriptions to place items within the
+   *   "tasks" section of the Jump List.
+   * @param {AString} aCustomTitle
+   *   An optional title for a custom sub-list within the Jump List that will be
+   *   populated via aCustomDescriptions. This must be supplied if
+   *   aCustomDescriptions is not empty.
+   * @param {WindowsJumpListShortcutDescription[]} aCustomDescriptions
+   *   0 or more WindowsJumpListShortcutDescriptions to place items within the
+   *   custom section of the Jump List. aCustomTitle must be supplied if this
+   *   array is non-empty.
+   * @returns {Promise<undefined, nsresult>}
+   *   Returns a Promise that resolves if the Jump List was properly written
+   *   to, and rejects otherwise with the nsresult of the failure.
+   * @throws NS_ERROR_INVALID_ARG
+   *   If any of the passed arguments do not meet the requirements set out
+   *   above.
+   * @throws NS_ERROR_FAILURE
+   *   If an attempt to communicate with the background thread fails.
+   */
+  [implicit_jscontext]
+  Promise populateJumpList(
+    in Array<jsval> aTaskDescriptions,
+    in AString aCustomTitle,
+    in Array<jsval> aCustomDescriptions
+  );
+
+  /**
+   * Removes all items from the Jump List.
+   *
+   * @returns {Promise<undefined, nsresult>}
+   *   Resolves with undefined on successfully clearing the Jump List. If it
+   *   fails to do so, it will reject with the failure code.
+   * @throws NS_ERROR_FAILURE
+   *   If an attempt to communicate with the background thread fails.
+   */
+  [implicit_jscontext]
+  Promise clearJumpList();
+};
diff --git a/widget/nsILegacyJumpListBuilder.idl b/widget/nsILegacyJumpListBuilder.idl
new file mode 100644
index 0000000000..999e658707
--- /dev/null
+++ b/widget/nsILegacyJumpListBuilder.idl
@@ -0,0 +1,161 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIArray;
+
+[scriptable, function, uuid(5131a62a-e99f-4631-9138-751f8aad1ae4)]
+interface nsILegacyJumpListCommittedCallback : nsISupports
+{
+  void done(in boolean result);
+};
+
+[scriptable, uuid(1FE6A9CD-2B18-4dd5-A176-C2B32FA4F683)]
+interface nsILegacyJumpListBuilder : nsISupports
+{
+  /**
+   * JumpLists
+   *
+   * Jump lists are built and then applied. Modifying an applied jump list is not
+   * permitted. Callers should begin the creation of a new jump list using
+   * initListBuild, add sub lists using addListToBuild, then commit the jump list
+   * using commitListBuild. Lists are built in real-time during the sequence of
+   * build calls, make sure to check for errors on each individual step.
+   *
+   * The default number of allowed items in a jump list is ten. Users can change
+   * the number through system preferences. User may also pin items to jump lists,
+   * which take up additional slots. Applications do not have control over the
+   * number of items allowed in jump lists; excess items added are dropped by the
+   * system. Item insertion priority is defined as first to last added.
+   *
+   * Users may remove items from jump lists after they are commited. The system
+   * tracks removed items between commits. A list of these items is returned by
+   * a call to initListBuild. nsILegacyJumpListBuilder does not filter entries added that
+   * have been removed since the last commit. To prevent repeatedly adding entries
+   * users have removed, applications are encoraged to track removed items
+   * internally.
+   *
+   * Each list is made up of an array of nsILegacyJumpListItem representing items
+   * such as shortcuts, links, and separators. See nsILegacyJumpListItem for information
+   * on adding additional jump list types.
+   */
+
+  /**
+   * List Types
+   */
+
+  /**
+   * Task List
+   *
+   * Tasks are common actions performed by users within the application. A task
+   * can be represented by an application shortcut and associated command line
+   * parameters or a URI. Task lists should generally be static lists that do not
+   * change often, if at all - similar to an application menu.
+   *
+   * Tasks are given the highest priority of all lists when space is limited.
+   */
+  const short JUMPLIST_CATEGORY_TASKS = 0;
+
+  /**
+   * Recent or Frequent list
+   *
+   * Recent and frequent lists are based on Window's recent document lists. The
+   * lists are generated automatically by Windows. Applications that use recent
+   * or frequent lists should keep document use tracking up to date by calling
+   * the SHAddToRecentDocs shell api.
+   */
+  const short JUMPLIST_CATEGORY_RECENT       = 1;
+  const short JUMPLIST_CATEGORY_FREQUENT     = 2;
+
+  /**
+   * Custom Lists
+   *
+   * Custom lists can be made up of tasks, links, and separators. The title of
+   * of the list is passed through the optional string parameter of addBuildList.
+   */
+  const short JUMPLIST_CATEGORY_CUSTOMLIST   = 3;
+
+  /**
+   * Indicates whether jump list taskbar features are supported by the current
+   * host.
+   */
+  readonly attribute short available;
+
+  /**
+   * JumpList management
+   *
+   * @throw NS_ERROR_NOT_AVAILABLE on all calls if taskbar functionality
+   * is not supported by the operating system.
+   */
+
+  /**
+   * Indicates if a commit has already occurred in this session.
+   */
+  readonly attribute boolean isListCommitted;
+
+  /**
+   * The maximum number of jump list items the current desktop can support.
+   */
+  readonly attribute short maxListItems;
+
+  /**
+   * Initializes a jump list build and returns a promise with the list of
+   * items the user removed since the last time a jump list was committed.
+   * Removed items can become state after initListBuild is called, lists
+   * should be built in single-shot fasion.
+   *
+   * @returns a promise with the list of items that were removed by the user
+   * since the last commit.
+   */
+  [implicit_jscontext]
+  Promise initListBuild();
+
+  /**
+   * Adds a list and if required, a set of items for the list.
+   *
+   * @param aCatType
+   *        The type of list to add.
+   * @param items
+   *        An array of nsILegacyJumpListItem items to add to the list.
+   * @param catName
+   *        For custom lists, the title of the list.
+   *
+   * @returns true if the operation completed successfully.
+   *
+   * @throw NS_ERROR_INVALID_ARG if incorrect parameters are passed for
+   * a particular category or item type.
+   * @throw NS_ERROR_ILLEGAL_VALUE if an item is added that was removed
+   * since the last commit.
+   * @throw NS_ERROR_UNEXPECTED on internal errors.
+   */
+  boolean addListToBuild(in short aCatType, [optional] in nsIArray items, [optional] in AString catName);
+
+  /**
+   * Aborts and clears the current jump list build.
+   */
+  void abortListBuild();
+
+  /**
+   * Commits the current jump list build to the Taskbar.
+   *
+   * @param callback
+   *        Receives one argument, which is true if the operation completed
+   *        successfully, otherwise it is false.
+   */
+  void commitListBuild([optional] in nsILegacyJumpListCommittedCallback callback);
+
+  /**
+   * Deletes any currently applied taskbar jump list for this application.
+   * Common uses would be the enabling of a privacy mode and uninstallation.
+   *
+   * @returns true if the operation completed successfully.
+   *
+   * @throw NS_ERROR_UNEXPECTED on internal errors.
+   */
+  boolean deleteActiveList();
+
+  void setAppUserModelID(in AString aAppUserModelId);
+};
diff --git a/widget/nsILegacyJumpListItem.idl b/widget/nsILegacyJumpListItem.idl
new file mode 100644
index 0000000000..29011215ac
--- /dev/null
+++ b/widget/nsILegacyJumpListItem.idl
@@ -0,0 +1,120 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIURI;
+interface nsILocalHandlerApp;
+interface nsIMutableArray;
+
+/**
+ * Implements Win7 Taskbar jump list item interfaces.
+ *
+ * Note to consumers: it's reasonable to expect we'll need support for other types
+ * of jump list items (an audio file, an email message, etc.). To add types,
+ * create the specific interface here, add an implementation class to WinJumpListItem,
+ * and add support to addListBuild & removed items processing.
+ *
+ */
+
+[scriptable, uuid(ACB8FB3C-E1B0-4044-8A50-E52C3E7C1057)]
+interface nsILegacyJumpListItem : nsISupports
+{
+  const short JUMPLIST_ITEM_EMPTY      = 0; // Empty list item
+  const short JUMPLIST_ITEM_SEPARATOR  = 1; // Separator
+  const short JUMPLIST_ITEM_LINK       = 2; // Web link item
+  const short JUMPLIST_ITEM_SHORTCUT   = 3; // Application shortcut
+
+  /**
+   * Retrieves the jump list item type.
+   */
+  readonly attribute short type;
+
+  /**
+   * Compare this item to another.
+   *
+   * Compares the type and other properties specific to this item's
+   * type.
+   *
+   * separator: type
+   * link: type, uri, title
+   * shortcut: type, handler app
+   */
+  boolean equals(in nsILegacyJumpListItem item);
+};
+
+/**
+ * A menu separator.
+ */
+
+[scriptable, uuid(69A2D5C5-14DC-47da-925D-869E0BD64D27)]
+interface nsILegacyJumpListSeparator : nsILegacyJumpListItem
+{
+  /* nothing needed here */
+};
+
+/**
+ * A URI link jump list item.
+ *
+ * Note the application must be the registered protocol
+ * handler for the protocol of the link.
+ */
+
+[scriptable, uuid(76EA47B1-C797-49b3-9F18-5E740A688524)]
+interface nsILegacyJumpListLink : nsILegacyJumpListItem
+{
+  /**
+   * Set or get the uri for this link item.
+   */
+  attribute nsIURI uri;
+
+  /**
+   * Set or get the title for a link item.
+   */
+  attribute AString uriTitle;
+};
+
+/**
+ * A generic application shortcut with command line support.
+ */
+
+[scriptable, uuid(CBE3A37C-BCE1-4fec-80A5-5FFBC7F33EEA)]
+interface nsILegacyJumpListShortcut : nsILegacyJumpListItem
+{
+  /**
+   * Set or get the handler app for this shortcut item.
+   *
+   * The handler app may also be used along with iconIndex to generate an icon
+   * for the jump list item.
+   *
+   * @throw NS_ERROR_FILE_NOT_FOUND if the handler app can
+   * not be found on  the system.
+   *
+   * @see faviconPageUri
+   */
+  attribute nsILocalHandlerApp app;
+
+  /**
+   * Set or get the icon displayed with the jump list item.
+   *
+   * Indicates the resource index of the icon contained within the handler
+   * executable which may be used as the jump list icon.
+   *
+   * @see faviconPageUri
+   */
+  attribute long iconIndex;
+
+  /**
+   * Set or get the URI of a page whose favicon may be used as the icon.
+   *
+   * When a jump list build occurs, the favicon to be used for the item is
+   * obtained using the following steps:
+   * - First, attempt to use the asynchronously retrieved and scaled favicon
+   * associated with the faviconPageUri.
+   * - If faviconPageUri is null, or if retrieving the favicon fails, fall
+   * back to using the handler executable and iconIndex.
+   */
+  attribute nsIURI faviconPageUri;
+};
diff --git a/widget/nsIMacDockSupport.idl b/widget/nsIMacDockSupport.idl
new file mode 100644
index 0000000000..04d6dca774
--- /dev/null
+++ b/widget/nsIMacDockSupport.idl
@@ -0,0 +1,71 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIStandaloneNativeMenu;
+
+/**
+ * Allow applications to interface with the Mac OS X Dock.
+ *
+ * Applications may indicate progress on their Dock icon. Only one such
+ * progress indicator is available to the entire application.
+ */
+
+[scriptable, uuid(8BE66B0C-5F71-4B74-98CF-6C2551B999B1)]
+interface nsIMacDockSupport : nsISupports
+{
+  /**
+   * Menu to use for application-specific dock menu items.
+   */
+  attribute nsIStandaloneNativeMenu dockMenu;
+
+  /**
+   * Activate the application. This should be used by an application to
+   * activate itself when a dock menu is selected as selection of a dock menu
+   * item does not automatically activate the application.
+   *
+   * @param aIgnoreOtherApplications If false, the application is activated
+   *        only if no other application is currently active. If true, the
+   *        application activates regardless.
+   */
+  void activateApplication(in boolean aIgnoreOtherApplications);
+
+  /**
+   * Text used to badge the dock tile.
+   */
+  attribute AString badgeText;
+
+  /**
+   * True if this app is in the list of apps that are persisted to the macOS
+   * Dock (as if the user selected "Keep in Dock").
+   */
+  readonly attribute bool isAppInDock;
+
+  /**
+   * Ensure that there is a tile for this app in the list of apps that are
+   * persisted to the macOS Dock (equivalent to the user selected "Keep in
+   * Dock").
+   *
+   * The position for the [new] app tile is:
+   *
+   * - its current position if it already exists, else
+   * - the position of `aAppToReplacePath` if it exists, else
+   * - directly after the last app with the same .app name, else
+   * - directly after the last known browser app (see `browserAppNames` in
+   *   nsMacDockSupport.mm), else
+   * - at the end of the persisted app list.
+   *
+   * @param aAppPath [optional] The path of the .app to persist to the Dock
+   *   (defaults to the path of the current app).
+   * @param aAppToReplacePath [optional] The path of a .app that should be
+   *   replaced if it is in the list of persisted apps.  This is useful when we
+   *   prompt the user to install the app when the app is being run directly
+   *   from a .dmg and the user may have dragged that .app file to the dock.
+   * @return true if the app was already in the list of persisted apps or if it
+   *   was successfully added, else returns false.
+   */
+  bool ensureAppIsPinnedToDock([optional] in AString aAppPath,
+                               [optional] in AString aAppToReplacePath);
+};
diff --git a/widget/nsIMacFinderProgress.idl b/widget/nsIMacFinderProgress.idl
new file mode 100644
index 0000000000..3c568bf1b5
--- /dev/null
+++ b/widget/nsIMacFinderProgress.idl
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+
+[scriptable, function, uuid(6BAE6D1C-7FFD-4354-8D7B-64697E98A801)]
+interface nsIMacFinderProgressCanceledCallback : nsISupports
+{
+  void canceled();
+};
+
+
+[scriptable, uuid(25A0B01F-54D4-4AEF-B2BF-C5764CDC68A8)]
+interface nsIMacFinderProgress : nsISupports
+{
+  /**
+  * Initialize and display a new Finder progressbar on the given file
+  *
+  * @param      path              The path of the file
+  *
+  * @param      canceledCallback  Callback which is called when cancelation is requested
+  */
+  void init(in AString path, in nsIMacFinderProgressCanceledCallback canceledCallback);
+
+  /**
+  * Update the current and total progess. If currentProgress and totalProgress are both 0,
+  * the progress is indetermined
+  *
+  * @param      currentProgress  The current progress
+  *
+  * @param      totalProgress    The total progress
+  */
+  void updateProgress(in unsigned long long currentProgress, in unsigned long long totalProgress);
+
+  /**
+  * End displaying the progressbar on the file
+  */
+  void end();
+};
diff --git a/widget/nsIMacSharingService.idl b/widget/nsIMacSharingService.idl
new file mode 100644
index 0000000000..cec0dae2d7
--- /dev/null
+++ b/widget/nsIMacSharingService.idl
@@ -0,0 +1,30 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+/**
+ * Allow applications to interface with the Mac OS X Sharing APIs.
+ */
+
+[scriptable, uuid(de59fe1a-46c8-490f-b04d-34545acb06c9)]
+interface nsIMacSharingService : nsISupports
+{
+  /**
+   * Get list of sharing providers
+   */
+  [implicit_jscontext] jsval getSharingProviders(in AString pageUrl);
+
+  /**
+   * Launch service with shareTitle with given url
+   */
+  void shareUrl(in AString serviceName,
+                in AString pageUrl,
+                in AString pageTitle);
+
+  /**
+   * Open the MacOS preferences window to the sharing panel
+   */
+  void openSharingPreferences();
+};
diff --git a/widget/nsIMacUserActivityUpdater.idl b/widget/nsIMacUserActivityUpdater.idl
new file mode 100644
index 0000000000..c5de948a43
--- /dev/null
+++ b/widget/nsIMacUserActivityUpdater.idl
@@ -0,0 +1,24 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIBaseWindow;
+
+/**
+  * Updates macOS widget code with the current URI and page title. Widget code
+  * can use this information to update NSUserActivity, enabling Handoff
+  * functionality.
+  */
+
+[scriptable, uuid(29046c8f-cba6-4ffa-9141-1685e96c4ea0)]
+interface nsIMacUserActivityUpdater : nsISupports
+{
+  /**
+   * Update active URL and page title for the given window.
+   */
+  void updateLocation(in AString pageUrl,
+                      in AString pageTitle,
+                      in nsIBaseWindow window);
+};
diff --git a/widget/nsIMacWebAppUtils.idl b/widget/nsIMacWebAppUtils.idl
new file mode 100644
index 0000000000..4d570a8bf0
--- /dev/null
+++ b/widget/nsIMacWebAppUtils.idl
@@ -0,0 +1,35 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIMacWebAppUtils;
+
+[scriptable, function, uuid(8c899c4f-58c1-4b74-9034-3bb64e484b68)]
+interface nsITrashAppCallback : nsISupports
+{
+  void trashAppFinished(in nsresult rv);
+};
+
+/**
+ * Allow MozApps API to locate and manipulate natively installed apps
+ */
+
+[scriptable, uuid(c69cf343-ea41-428b-b161-4655fd54d8e7)]
+interface nsIMacWebAppUtils : nsISupports {
+  /**
+   * Find the path for an app with the given signature.
+   */
+  AString pathForAppWithIdentifier(in AString bundleIdentifier);
+
+  /**
+   * Launch the app with the given identifier, if it exists.
+   */
+  void launchAppWithIdentifier(in AString bundleIdentifier);
+
+  /**
+   * Move the app from the given directory to the Trash.
+   */
+  void trashApp(in AString path, in nsITrashAppCallback callback);
+};
diff --git a/widget/nsIPaper.idl b/widget/nsIPaper.idl
new file mode 100644
index 0000000000..0ec957d221
--- /dev/null
+++ b/widget/nsIPaper.idl
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[scriptable, uuid(a4dd9675-6311-45a9-a547-44e0127304a6)]
+interface nsIPaper : nsISupports
+{
+  /**
+   * The internal name of the paper (a fixed, non-localized ID).
+   * (For CUPS, this is the PWG-standardized name as used internally by CUPS;
+   * on Windows, it is the integer paper ID as a string.)
+   */
+  readonly attribute AString id;
+
+  /**
+   * The human-readable (potentially localized) name of the paper.
+   */
+  readonly attribute AString name;
+
+  /**
+   * The width of the paper assuming portrait orientation, in points.
+   * That is, the length of the shorter edges of the paper.
+   */
+  readonly attribute double width;
+
+  /**
+   * The height of the paper assuming portrait orientation, in points.
+   * That is, the length of the longer edges of the paper.
+   */
+  readonly attribute double height;
+
+  /**
+   * The Promise resolves with an nsIPaperMargin object. The margin widths contained
+   * in that object's top/bottom/left/right properties are relative to the paper in
+   * portrait orientation. That is, top and bottom are the margins for the short edges,
+   * and left and right are the margins for the long edges.
+   */
+  [implicit_jscontext] readonly attribute Promise unwriteableMargin;
+};
diff --git a/widget/nsIPaperMargin.idl b/widget/nsIPaperMargin.idl
new file mode 100644
index 0000000000..80242f63b3
--- /dev/null
+++ b/widget/nsIPaperMargin.idl
@@ -0,0 +1,16 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+// A margin for a sheet of paper.
+[builtinclass, scriptable, uuid(0858d1a7-b646-4b15-a1e8-7eb5ab572d0a)]
+interface nsIPaperMargin : nsISupports
+{
+  [infallible] readonly attribute double top;
+  [infallible] readonly attribute double right;
+  [infallible] readonly attribute double bottom;
+  [infallible] readonly attribute double left;
+};
diff --git a/widget/nsIPrintDialogService.idl b/widget/nsIPrintDialogService.idl
new file mode 100644
index 0000000000..1c79ddd76b
--- /dev/null
+++ b/widget/nsIPrintDialogService.idl
@@ -0,0 +1,66 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Doc interface here */
+
+#include "nsISupports.idl"
+#include "nsIWebProgressListener.idl"
+#include "nsIPrintSettings.idl"
+#include "nsIObserver.idl"
+
+interface mozIDOMWindowProxy;
+
+/**
+ * Service for opening native print dialogs provided by the operating system.
+ * (The widget code may customize the dialog.)
+ */
+[scriptable, uuid(88af6712-a9fd-4393-9af3-3ffbb1f2caaf)]
+interface nsIPrintDialogService : nsISupports
+{
+  /**
+   * Initialize the service.
+   */
+  void init();
+
+  /**
+   * Show the print dialog.
+   * @param aParent   A DOM window the dialog will be parented to.
+   * @param aHaveSelection A boolean indicating whether the document to be
+   *                  printed has some selected text, which is used to
+   *                  determine whether the "Print selection only" radio
+   *                  button is enabled in the print settings dialog.
+   * @param aSettings On entry, this contains initial settings for the
+   *                  print dialog. On return, if the print operation should
+   *                  proceed, then this has been updated with the settings
+   *                  that the user selected in the dialog.
+   * @return NS_OK if the print operation should proceed
+   * @return NS_ERROR_ABORT if the user indicated not to proceed
+   * @return a suitable error for failures to show the print dialog.
+   */
+  void showPrintDialog(in mozIDOMWindowProxy aParent,
+                       in boolean aHaveSelection,
+                       in nsIPrintSettings aPrintSettings);
+
+  /**
+   * Show the page setup dialog. Note that there is no way to tell whether the
+   * user clicked OK or Cancel on the dialog.
+   * @param aParent   A DOM window the dialog will be parented to.
+   * @param aSettings On entry, this contains initial settings for the
+   *                  page setup dialog. On return, if the dialog wasn't
+   *                  cancelled, then this has been updated with the settings
+   *                  that the user selected in the dialog.
+   */
+  void showPageSetupDialog(in mozIDOMWindowProxy aParent,
+                           in nsIPrintSettings aPrintSettings);
+
+};
+
+%{C++
+#define NS_PRINTDIALOGSERVICE_IID \
+ {0x88af6712, 0xa9fd, 0x4393, { 0x9a, 0xf3, 0x3f, 0xfb, 0xb1, 0xf2, 0xca, 0xaf}}
+
+#define NS_PRINTDIALOGSERVICE_CONTRACTID \
+  ("@mozilla.org/widget/printdialog-service;1")
+%}
diff --git a/widget/nsIPrintSettings.idl b/widget/nsIPrintSettings.idl
new file mode 100644
index 0000000000..efed9efce6
--- /dev/null
+++ b/widget/nsIPrintSettings.idl
@@ -0,0 +1,405 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+%{ C++
+#include "nsMargin.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+struct PrintSettingsInitializer;
+}
+%}
+
+/**
+ * Native types
+ */
+native nsNativeIntMargin(nsIntMargin);
+[ref] native nsNativeIntMarginRef(nsIntMargin);
+native PrintSettingsInitializer(mozilla::PrintSettingsInitializer);
+
+interface nsIOutputStream;
+
+/**
+ * Simplified graphics interface for JS rendering.
+ */
+[scriptable, builtinclass, uuid(ecc5cbad-57fc-4731-b0bd-09e865bd62ad)]
+interface nsIPrintSettings : nsISupports
+{
+  /**
+   * PrintSettings to be Saved Navigation Constants
+   */
+  /* Flag 0x00000001 is unused */
+  const unsigned long kInitSaveHeaderLeft     = 0x00000002;
+  const unsigned long kInitSaveHeaderCenter   = 0x00000004;
+  const unsigned long kInitSaveHeaderRight    = 0x00000008;
+  const unsigned long kInitSaveFooterLeft     = 0x00000010;
+  const unsigned long kInitSaveFooterCenter   = 0x00000020;
+  const unsigned long kInitSaveFooterRight    = 0x00000040;
+  const unsigned long kInitSaveBGColors       = 0x00000080;
+  const unsigned long kInitSaveBGImages       = 0x00000100;
+  const unsigned long kInitSavePaperSize      = 0x00000200;
+  /* Flag 0x00000400 is unused */
+  const unsigned long kInitSaveDuplex         = 0x00000800;
+  /* Flag 0x00001000 is unused */
+  /* Flag 0x00002000 is unused */
+  const unsigned long kInitSaveUnwriteableMargins = 0x00004000;
+  const unsigned long kInitSaveEdges          = 0x00008000;
+
+  const unsigned long kInitSaveReversed       = 0x00010000;
+  const unsigned long kInitSaveInColor        = 0x00020000;
+  const unsigned long kInitSaveOrientation    = 0x00040000;
+
+  const unsigned long kInitSavePrinterName    = 0x00100000;
+  const unsigned long kInitSavePrintToFile    = 0x00200000;
+  const unsigned long kInitSaveToFileName     = 0x00400000;
+  const unsigned long kInitSavePageDelay      = 0x00800000;
+  const unsigned long kInitSaveMargins        = 0x01000000;
+  /* Flag 0x02000000 is unused */
+
+  const unsigned long kInitSaveShrinkToFit    = 0x08000000;
+  const unsigned long kInitSaveScaling        = 0x10000000;
+
+  const unsigned long kInitSaveAll            = 0xFFFFFFFF;
+
+  // These settings should be read from global prefs. Other settings should be
+  // read only from printer-specific prefs.
+  const unsigned long kGlobalSettings =
+      kInitSaveHeaderLeft | kInitSaveHeaderCenter | kInitSaveHeaderRight |
+      kInitSaveFooterLeft | kInitSaveFooterCenter | kInitSaveFooterRight |
+      kInitSaveEdges | kInitSaveReversed | kInitSaveInColor |
+      kInitSaveBGColors | kInitSaveBGImages | kInitSaveShrinkToFit;
+
+  // These settings may be changed by native print dialog and should be
+  // persisted when changed.
+  const unsigned long kPrintDialogPersistSettings =
+      kGlobalSettings | kInitSavePaperSize | kInitSaveDuplex |
+      kInitSaveEdges | kInitSaveReversed | kInitSaveInColor |
+      kInitSaveOrientation | kInitSavePageDelay | kInitSaveMargins |
+      kInitSaveShrinkToFit | kInitSaveScaling;
+
+  /* Justification Enums */
+  const long kJustLeft   = 0;
+  const long kJustCenter = 1;
+  const long kJustRight  = 2;
+
+  /** Page Size Unit Constants */
+  const short kPaperSizeInches      = 0;
+  const short kPaperSizeMillimeters = 1;
+
+  /** Orientation Constants */
+  const short kPortraitOrientation  = 0;
+  const short kLandscapeOrientation = 1;
+
+  /** Output file format */
+  const short kOutputFormatNative = 0;
+  const short kOutputFormatPDF    = 2;
+
+  /** Output destination */
+  cenum OutputDestinationType : 8 {
+    kOutputDestinationPrinter = 0,
+    kOutputDestinationFile = 1,
+    kOutputDestinationStream = 2,
+  };
+
+  /**
+   * Duplex printing options.
+   *
+   * Note that other libraries refer to equivalent duplex settings using
+   * various sets of terminology. This can be confusing and inconsistent both
+   * with other libraries, and with the behavior that these terms intend to describe.
+   *
+   * kDuplexNone is equivalent to Simplex. Thankfully, both of these terms are
+   * consistent with the behavior that they describe, which is to have single-sided
+   * printing per sheet.
+   *
+   * kDuplexFlipOnLongEdge is equivalent to the following platform-specific constants:
+   *   CUPS/macOS: NoTumble
+   *      Windows: DMDUP_VERTICAL
+   *          GTK: GTK_PRINT_DUPLEX_HORIZONTAL
+   *
+   * kDuplexFlipOnShortEdge is equivalent to the following platform-specific constants:
+   *   CUPS/macOS: Tumble
+   *      Windows: DMDUP_HORIZONTAL
+   *          GTK: GTK_PRINT_DUPLEX_VERTICAL
+   *
+   *
+   * Notice that the GTK and Windows constants have opposite meanings for
+   * VERTICAL and HORIZONTAL.
+   *
+   * To make matters more confusing, these platform-specific terms describe different
+   * behavior (from the user's perspective) depending on whether the sheet is in
+   * portrait vs. landscape orientation.
+   *
+   * For example, the generic term "tumble" describes behavior where a sheet flips over
+   * a binding on the top edge (like a calendar). This requires that the back side of
+   * the sheet is printed upside down with respect to the front side of the sheet,
+   * so that its content appears upright to the reader when they tumble-flip the
+   * sheet over the top-edge binding.
+   *
+   * However, the CUPS/macOS Tumble setting only inverts the back side of the
+   * sheet in portrait orientation. When you switch to landscape orientation, the
+   * Tumble setting behaves like a book-like sheet flip, where the front and back
+   * sides of the sheet are both printed upright with respect to each other.
+   *
+   * This is why it is more consistent and more clear to think of these terms
+   * with regard to sheets being bound on the long edge or the short edge.
+   *
+   * kDuplexFlipOnLongEdge  + Portrait  =     book-like flip (front/back same direction)
+   * kDuplexFlipOnLongEdge  + Landscape = calendar-like flip (front/back inverted)
+   *
+   * kDuplexFlipOnShortEdge + Portrait  = calendar-like flip (front/back inverted)
+   * kDuplexFlipOnShortEdge + Landscape =     book-like flip (front/back same direction)
+   *
+   * The long-edge and short-edge terminology unfortunately breaks down when printing
+   * with square sheet dimensions. Thankfully this edge case (hah) is quite uncommon,
+   * since most standard printing paper dimensions are not square. Such a paper size
+   * would even break the uniformly used portrait and landscape terminology.
+   */
+  const short kDuplexNone = 0;
+  const short kDuplexFlipOnLongEdge = 1;
+  const short kDuplexFlipOnShortEdge = 2;
+
+  /**
+   * Get the page size in twips, considering the
+   * orientation (portrait or landscape).
+   */
+  void GetEffectivePageSize(out double aWidth, out double aHeight);
+
+  /**
+   * Get the printed sheet size in twips, considering both the user-specified
+   * orientation (portrait or landscape) *as well as* the fact that we might be
+   * inverting the orientation to account for 2 or 6 pages-per-sheet.
+   *
+   * This API will usually behave the same (& return the same thing) as
+   * GetEffectivePageSize, *except for* when we are printing with 2 or 6
+   * pages-per-sheet, in which case the return values (aWidth & aHeight) will
+   * be swapped with respect to what GetEffectivePageSize would return.
+   *
+   * Callers should use this method rather than GetEffectivePageSize when they
+   * really do want the size of the sheet of paper to be printed, rather than
+   * the possibly-"virtualized"-via-pages-per-sheet page size.
+   */
+  [noscript, notxpcom, nostdcall] void GetEffectiveSheetSize(out double aWidth,
+                                                             out double aHeight);
+
+  /**
+   * Get the orientation of a printed sheet. This is usually the same as the
+   * 'orientation' attribute (which is the orientation of individual pages),
+   * except when we're printing with 2 or 6 pages-per-sheet, in which case
+   * it'll be the opposite value.
+   *
+   * Note that this value is not independently settable. Its value is fully
+   * determined by the 'orientation' and 'numPagesPerSheet' attributes.
+   */
+  [noscript, notxpcom, nostdcall] long GetSheetOrientation();
+
+  /**
+   * Convenience getter, which returns true IFF the value of `numPagesPerSheet`
+   * would require us to orient the pages orthogonally to the sheet in order
+   * to make best use of the space on the sheet. Specifically, this returns
+   * true IFF `numPagesPerSheet` is set to 2 or 6 pages-per-sheet.
+   */
+  [noscript, notxpcom, nostdcall] bool HasOrthogonalPagesPerSheet();
+
+  /**
+   * Makes a new copy
+   */
+  nsIPrintSettings clone();
+
+  /**
+   * Assigns the internal values from the "in" arg to the current object
+   */
+  void assign(in nsIPrintSettings aPS);
+
+  /**
+   * Returns true if the settings will result in an equivalent preview and
+   * therefore print. The printer name is ignored and it allows for a small
+   * delta in sizes to allow for rounding differences.
+   */
+  bool equivalentTo(in nsIPrintSettings aPrintSettings);
+
+  /**
+   * The edge measurements define the positioning of the headers
+   * and footers on the page. They're treated as an offset from the edges of
+   * the page, but are forced to be at least the "unwriteable margin"
+   * (described below).
+   */
+  attribute double  edgeTop;     /*  these are in inches */
+  attribute double  edgeLeft;
+  attribute double  edgeBottom;
+  attribute double  edgeRight;
+
+  /**
+   * The margins define the positioning of the content on the page.
+   * and footers on the page. They're treated as an offset from the edges of
+   * the page, but are forced to be at least the "unwriteable margin," unless
+   * set to be ignored (described below).
+   */
+  attribute double  marginTop;     /*  these are in inches */
+  attribute double  marginLeft;
+  attribute double  marginBottom;
+  attribute double  marginRight;
+  /**
+   * The unwriteable margin defines the printable region of the paper.
+   */
+  attribute double  unwriteableMarginTop;     /*  these are in inches */
+  attribute double  unwriteableMarginLeft;
+  attribute double  unwriteableMarginBottom;
+  attribute double  unwriteableMarginRight;
+
+  attribute double  scaling;      /* values 0.0 - 1.0 */
+  [infallible] attribute boolean printBGColors; /* Print Background Colors */
+  [infallible] attribute boolean printBGImages; /* Print Background Images */
+
+  /**
+   * Whether @page rule margins should be honored or not. If the @page
+   * rule sets its margins to zero, we automatically ignore unwriteable
+   * margins, but nonzero values will be clamped to unwriteable margins.
+   */
+  [infallible] attribute boolean honorPageRuleMargins;
+
+  /**
+   * Whether @page rule size should be used for the output paper size.
+   */
+  [infallible] attribute boolean usePageRuleSizeAsPaperSize;
+
+  /**
+   * Whether unwritable margins should be ignored. This should be set when
+   * when the user explicitly requests "Margins: None", e.g. for documents
+   * where accurate scaling matters. Note: While `honorPageRuleMargins` and
+   * this flag can't be set at the same time through the UI, doing so will
+   * cause even the nonzero @page rule margins to ignore unwriteable margins.
+   */
+  [infallible] attribute boolean ignoreUnwriteableMargins;
+
+  /** Whether to draw guidelines showing the margin settings */
+  [infallible] attribute boolean showMarginGuides;
+
+  /** Whether to only print the selected nodes */
+  [infallible] attribute boolean printSelectionOnly;
+
+  attribute AString title;
+  attribute AString docURL;
+
+  attribute AString headerStrLeft;
+  attribute AString headerStrCenter;
+  attribute AString headerStrRight;
+
+  attribute AString footerStrLeft;
+  attribute AString footerStrCenter;
+  attribute AString footerStrRight;
+
+  attribute boolean printSilent;         /* print without putting up the dialog */
+  [infallible] attribute boolean shrinkToFit; /* shrinks content to fit on page */
+
+  /* Additional XP Related */
+  attribute AString paperId;       /* identifier of paper (not display name) */
+  attribute double  paperWidth;    /* width of the paper in inches or mm */
+  attribute double  paperHeight;   /* height of the paper in inches or mm */
+  attribute short   paperSizeUnit; /* paper is in inches or mm */
+
+  attribute boolean printReversed;
+  [infallible] attribute boolean printInColor;  /* a false means grayscale */
+  attribute long    orientation;   /*  see orientation consts */
+  attribute long    numCopies;
+
+  /**
+   * For numPagesPerSheet, we support these values: 1, 2, 4, 6, 9, 16.
+   *
+   * Unsupported values will be treated internally as 1 page per sheet, and
+   * will trigger assertion failures in debug builds.
+   */
+  attribute long    numPagesPerSheet;
+
+  /** Output device information */
+  [infallible] attribute nsIPrintSettings_OutputDestinationType outputDestination;
+  [infallible] attribute short outputFormat;
+
+  /**
+   * If outputDestination==kOutputDestinationPrinter, this is set to the name
+   * of the printer that the print output should be saved to, but only in the
+   * parent process (we don't want to leak printer names to potentially
+   * compromised content processes).
+   */
+  attribute AString printerName;
+
+  /**
+   * If outputDestination==kOutputDestinationFile, this is set to the path
+   * of the file that the print output should be saved to, but only in the
+   * parent process (we don't want to leak system paths to potentially
+   * compromised content processes).
+   */
+  attribute AString toFileName;
+
+  attribute nsIOutputStream outputStream; /* for kOutputDestinationPrinter */
+
+  [infallible] attribute long printPageDelay; /* in milliseconds */
+
+  [infallible] attribute long resolution;     /* print resolution (dpi) */
+
+  [infallible] attribute long duplex;         /* duplex mode */
+
+  /* initialize helpers */
+  /**
+   * This attribute tracks whether the PS has been initialized
+   * from a printer specified by the "printerName" attr.
+   * If a different name is set into the "printerName"
+   * attribute than the one it was initialized with the PS
+   * will then get initialized from that printer.
+   */
+  attribute boolean isInitializedFromPrinter;
+
+  /**
+   * This attribute tracks whether the PS has been initialized
+   * from prefs. If a different name is set into the "printerName"
+   * attribute than the one it was initialized with the PS
+   * will then get initialized from prefs again.
+   */
+  attribute boolean isInitializedFromPrefs;
+
+  /* C++ Helper Functions */
+  [noscript] void SetMarginInTwips(in nsNativeIntMarginRef aMargin);
+  [noscript] void SetEdgeInTwips(in nsNativeIntMarginRef aEdge);
+  [noscript, notxpcom, nostdcall] nsNativeIntMargin GetMarginInTwips();
+  [noscript, notxpcom, nostdcall] nsNativeIntMargin GetEdgeInTwips();
+
+  /**
+   * Sets/Gets the "unwriteable margin" for the page format.  This defines
+   * the boundary from which we'll measure the EdgeInTwips and MarginInTwips
+   * attributes, to place the headers and content, respectively.
+   *
+   * Note: Implementations of SetUnwriteableMarginInTwips should handle
+   * negative margin values by falling back on the system default for
+   * that margin.
+   */
+  [noscript] void SetUnwriteableMarginInTwips(in nsNativeIntMarginRef aEdge);
+  [noscript, notxpcom, nostdcall] nsNativeIntMargin GetUnwriteableMarginInTwips();
+
+  /**
+   * Get more accurate print ranges from the superior interval
+   * (startPageRange, endPageRange). The aPages array is populated with a
+   * list of pairs (start, end), where the endpoints are included. The print
+   * ranges (start, end), must not overlap and must be in the
+   * (startPageRange, endPageRange) scope.
+   *
+   * If there are no print ranges the aPages array is empty.
+   */
+  attribute Array<long> pageRanges;
+
+  /**
+   * Get a PrintSettingsInitializer populated with the relevant current settings.
+   */
+  [notxpcom, nostdcall] PrintSettingsInitializer getSettingsInitializer();
+
+%{C++
+  static bool IsPageSkipped(int32_t aPageNum, const nsTArray<int32_t>& aRanges);
+%}
+};
+
+%{ C++
+already_AddRefed<nsIPrintSettings> CreatePlatformPrintSettings(const mozilla::PrintSettingsInitializer&);
+%}
diff --git a/widget/nsIPrintSettingsService.idl b/widget/nsIPrintSettingsService.idl
new file mode 100644
index 0000000000..3b33724c34
--- /dev/null
+++ b/widget/nsIPrintSettingsService.idl
@@ -0,0 +1,151 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Interface to the Service for gwetting the Global PrintSettings object
+   or a unique PrintSettings object
+*/
+
+#include "nsISupports.idl"
+
+interface nsIPrintSettings;
+
+%{ C++
+namespace mozilla {
+namespace embedding {
+  class PrintData;
+}
+}
+%}
+
+/**
+ * Native types
+ */
+[ref] native PrintDataRef(const mozilla::embedding::PrintData);
+[ptr] native PrintDataPtr(mozilla::embedding::PrintData);
+
+[scriptable, uuid(841387C8-72E6-484b-9296-BF6EEA80D58A)]
+interface nsIPrintSettingsService : nsISupports
+{
+  /**
+   * Returns the default print settings as used for printing.
+   */
+  [noscript] readonly attribute nsIPrintSettings defaultPrintSettingsForPrinting;
+
+  /**
+   * Creates a new nsIPrintSettings object.
+   *
+   * Initializes the settings object from the unprefixed printer
+   * (Note: this may not happen if there is an OS specific implementation.)
+   */
+  nsIPrintSettings createNewPrintSettings();
+
+  /**
+   * The name of the last printer used. Note that this may not be set, or may
+   * no longer be a valid printer. The caller is responsible for checking and
+   * falling back to some other printer (such as the system default printer).
+   *
+   * XXX: make it [infallible] when AString supports that (bug 1491187).
+   */
+  readonly attribute AString lastUsedPrinterName;
+
+  /**
+   * Initializes certain settings from the native printer into the PrintSettings
+   * if aPrinterName is null then it uses the default printer name if it can
+   * These settings include, but are not limited to:
+   *   Page Orientation
+   *   Page Size
+   *   Number of Copies
+   */
+  void initPrintSettingsFromPrinter(in AString aPrinterName,
+                                    in nsIPrintSettings aPrintSettings);
+
+  /**
+   * Reads PrintSettings values from Prefs,
+   * the values to be read are indicated by the "flags" arg.
+   *
+   * aPrintSettings should be initialized with the name of a printer. First
+   * it reads in the PrintSettings from the last print job. Then it uses the
+   * PrinterName in the PrinterSettings to read any settings that were saved
+   * just for that printer.
+   *
+   * aPS - PrintSettings to have its settings read
+   * aUsePrinterNamePrefix - indicates whether to use the printer name as a prefix
+   * aFlags - indicates which prefs to read, see nsIPrintSettings.idl for the
+   *          const values.
+   *
+   * Items not read:
+   *   startPageRange, endPageRange, scaling, printRange, title
+   *   docURL, isCancelled,
+   *   printSilent, shrinkToFit, numCopies,
+   *   printerName
+   *
+   */
+  void initPrintSettingsFromPrefs(in nsIPrintSettings aPrintSettings, in boolean aUsePrinterNamePrefix, in unsigned long aFlags);
+
+  /**
+   * As long as the pref print.save_print_settings isn't set to false, this
+   * saves to prefs the settings from aPrintSettings that are indicated by
+   * aFlags.
+   *
+   * If there is no PrinterName in the PrinterSettings
+   * the values are saved as the "generic" values not associated with any printer.
+   * If a PrinterName is there, then it saves the items qualified for that Printer
+   *
+   * aPS - PrintSettings to have its settings saved
+   * aFlags - indicates which prefs to save, see nsIPrintSettings.idl for the const values.
+   *
+   * Items not written:
+   *   startPageRange, endPageRange, scaling, printRange, title
+   *   docURL, isCancelled,
+   *   printSilent, shrinkToFit, numCopies
+   *
+   */
+  void maybeSavePrintSettingsToPrefs(in nsIPrintSettings aPrintSettings, in unsigned long aFlags);
+
+  /**
+   * As long as the pref print.save_print_settings isn't set to false, this
+   * saves the given printer name as the last used printer name.
+   */
+  void maybeSaveLastUsedPrinterNameToPrefs(in AString aPrinterName);
+
+  /**
+   * Given some nsIPrintSettings,
+   * populates a PrintData representing them which can be sent over IPC. Values
+   * are only ever read from aSettings and aWBP.
+   *
+   * @param aSettings
+   *        An nsIPrintSettings for a print job.
+   * @param data
+   *        Pointer to a pre-existing PrintData to populate.
+   *
+   * @return nsresult
+   */
+  [noscript]
+  void SerializeToPrintData(in nsIPrintSettings aPrintSettings,
+                            in PrintDataPtr data);
+
+  /**
+   * This function is the opposite of SerializeToPrintData, in that it takes
+   * a PrintData, and populates a pre-existing nsIPrintSettings with the data
+   * from PrintData.
+   *
+   * @param PrintData
+   *        Printing information sent through IPC.
+   * @param settings
+   *        A pre-existing nsIPrintSettings to populate with the PrintData.
+   *
+   * @return nsresult
+   */
+  [noscript]
+  void DeserializeToPrintSettings(in PrintDataRef data,
+                                  in nsIPrintSettings aPrintSettings);
+
+};
+
+%{C++
+// {841387C8-72E6-484b-9296-BF6EEA80D58A}
+#define NS_PRINTSETTINGSSERVICE_IID \
+ {0x841387c8, 0x72e6, 0x484b, { 0x92, 0x96, 0xbf, 0x6e, 0xea, 0x80, 0xd5, 0x8a}}
+%}
diff --git a/widget/nsIPrintSettingsWin.idl b/widget/nsIPrintSettingsWin.idl
new file mode 100644
index 0000000000..fae68a9fdd
--- /dev/null
+++ b/widget/nsIPrintSettingsWin.idl
@@ -0,0 +1,56 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+%{ C++
+#include "windows.h"
+%}
+
+/**
+ * Native types
+ */
+  [ptr] native nsDevMode(DEVMODEW);
+  native nsHdc(HDC);
+
+/**
+ * Simplified PrintSettings for Windows interface
+ */
+[uuid(c63eed41-6ac5-459e-8a64-033eb9ad770a)]
+interface nsIPrintSettingsWin : nsISupports
+{
+  /**
+   * Data Members
+   *
+   * Each of these data members make a copy
+   * of the contents. If you get the value,
+   * you own the memory.
+   *
+   * The following three pieces of data are needed
+   * to create a DC for printing. These are typcially
+   * gotten via the PrintDLG call ro can be obtained
+   * via the "m_pd" data member of the CPrintDialog
+   * in MFC.
+   */
+  [noscript] attribute AString deviceName;
+  [noscript] attribute AString driverName;
+
+  [noscript] attribute nsDevMode devMode;
+
+  /**
+   * Copy relevant print settings from native Windows device.
+   *
+   * @param hdc HDC to copy from
+   * @param devMode DEVMODE to copy from
+   */
+  [notxpcom] void copyFromNative(in nsHdc hdc, in nsDevMode devMode);
+
+  /**
+   * Copy relevant print settings to native windows structures.
+   *
+   * @param devMode DEVMODE to be populated.
+   */
+  [notxpcom] void copyToNative(in nsDevMode devMode);
+};
diff --git a/widget/nsIPrinter.idl b/widget/nsIPrinter.idl
new file mode 100644
index 0000000000..d95671f681
--- /dev/null
+++ b/widget/nsIPrinter.idl
@@ -0,0 +1,83 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIPaper.idl"
+#include "nsIPrintSettings.idl"
+#include "nsISupports.idl"
+
+[scriptable, uuid(855ae9dd-62a4-64aa-9c60-b1078ff028f1)]
+interface nsIPrinterInfo : nsISupports
+{
+  /**
+   * An array of nsIPaper instances that represents the available paper sizes.
+   */
+  readonly attribute Array<nsIPaper> paperList;
+  /**
+   * nsIPrintSettings object containing the default settings for a printer.
+   */
+  readonly attribute nsIPrintSettings defaultSettings;
+};
+
+[scriptable, uuid(d2dde9bb-df86-469c-bfcc-fd95a44b1db8)]
+interface nsIPrinter : nsISupports
+{
+  /**
+   * The name of the printer.
+   */
+  readonly attribute AString name;
+
+  /**
+   * The system name of the printer.
+   *
+   * This may be faster for lookup in nsIPrinterList functions, but will only
+   * work for functions that will accept the system name.
+   */
+  readonly attribute AString systemName;
+
+  /**
+   * Returns a Promise that resolves to a nsIPrinterInfo.
+   * This will contain the default printer settings, and the list of paper
+   * sizes supported by the printer.
+   */
+  [implicit_jscontext]
+  readonly attribute Promise printerInfo;
+
+  /**
+   * Returns a Promise that resolves to a new settings object that contains all
+   * of the settings from aSettingsToCopyFrom that are valid for this printer.
+   * Any settings that are not valid for the printer are set to default/fallback
+   * values.
+   */
+  [implicit_jscontext]
+  Promise copyFromWithValidation(in nsIPrintSettings aSettingsToCopyFrom);
+
+  /**
+   * Returns a Promise that resolves to true or false to indicate whether this
+   * printer supports duplex printing.
+   */
+  [implicit_jscontext]
+  readonly attribute Promise supportsDuplex;
+
+  /**
+   * Returns a Promise that resolves to true or false to indicate whether this
+   * printer supports color printing.
+   */
+  [implicit_jscontext]
+  readonly attribute Promise supportsColor;
+
+  /**
+   * Returns a Promise that resolves to true or false to indicate whether this
+   * printer supports monochrome printing.
+   */
+  [implicit_jscontext]
+  readonly attribute Promise supportsMonochrome;
+
+  /**
+   * Returns a Promise that resolves to true or false to indicate whether this
+   * printer supports collation.
+   */
+  [implicit_jscontext]
+  readonly attribute Promise supportsCollation;
+};
diff --git a/widget/nsIPrinterList.idl b/widget/nsIPrinterList.idl
new file mode 100644
index 0000000000..d49cedc16e
--- /dev/null
+++ b/widget/nsIPrinterList.idl
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "nsIPrinter.idl"
+#include "nsIPrintSettings.idl"
+
+[scriptable, uuid(5e738fff-404c-4c94-9189-e8f2cce93e94)]
+interface nsIPrinterList : nsISupports
+{
+  /**
+   * Initializes certain settings from the native printer into the PrintSettings
+   * These settings include, but are not limited to:
+   *   Page Orientation
+   *   Page Size
+   *   Number of Copies
+   */
+  void initPrintSettingsFromPrinter(in AString aPrinterName,
+                                    in nsIPrintSettings aPrintSettings);
+
+  /**
+   * The system default printer name. This is not necessarily gecko's
+   * default printer; see nsIPrintSettingsService.lastUsedPrinterName
+   * for that.
+   */
+  readonly attribute AString systemDefaultPrinterName;
+
+  /**
+   * Returns a promise that resolves to the printer of a given name, or is
+   * rejected if there is no such printer.
+   */
+  [implicit_jscontext] Promise getPrinterByName(in AString aPrinterName);
+
+  /**
+   * Returns a promise that resolves to the printer of a given system name, or
+   * is rejected if there is no such printer.
+   * This may be more efficient than using getNamedPrinter, but requires the
+   * caller to know the system name of the printer they want to find.
+   */
+  [implicit_jscontext] Promise getPrinterBySystemName(in AString aPrinterName);
+
+  /**
+   * Returns a promise that resolves to the printer of the given name, or
+   * the default system printer, or is rejected if there are no printers
+   * available.
+   */
+  [implicit_jscontext] Promise getNamedOrDefaultPrinter(in AString aPrinterName);
+
+  /**
+   * Returns a promise that resolves to an array of printers.
+   */
+  [implicit_jscontext] readonly attribute Promise printers;
+
+  /**
+   * Returns a Promise that resolves to an array of nsIPaper instances
+   * for common paper sizes suitable to be supported for Save to PDF.
+   */
+  [implicit_jscontext] readonly attribute Promise fallbackPaperList;
+};
diff --git a/widget/nsIRollupListener.h b/widget/nsIRollupListener.h
new file mode 100644
index 0000000000..b52e768a14
--- /dev/null
+++ b/widget/nsIRollupListener.h
@@ -0,0 +1,81 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsIRollupListener_h__
+#define __nsIRollupListener_h__
+
+#include "nsTArray.h"
+#include "nsPoint.h"
+#include "Units.h"
+
+class nsIContent;
+class nsIWidget;
+
+class nsIRollupListener {
+ public:
+  enum class FlushViews : bool { No, Yes };
+  enum class AllowAnimations : bool { No, Yes };
+  struct RollupOptions {
+    // aCount is the number of popups in a chain to close. If this is
+    // zero, then all popups are closed.
+    uint32_t mCount = 0;
+    // If this is true, then views should be flushed after the rollup.
+    FlushViews mFlush = FlushViews::No;
+    // This is the mouse pointer position where the event that triggered the
+    // rollup occurred, which may be nullptr.
+    const mozilla::LayoutDeviceIntPoint* mPoint = nullptr;
+    // Whether to allow panel animations.
+    AllowAnimations mAllowAnimations = AllowAnimations::Yes;
+  };
+
+  /**
+   * Notifies the object to rollup, optionally returning the node that
+   * was just rolled up in aLastRolledUp, if non-null.
+   *
+   * aLastRolledUp is not addrefed.
+   *
+   * Returns true if the event that the caller is processing should be consumed.
+   */
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY
+  virtual bool Rollup(const RollupOptions&,
+                      nsIContent** aLastRolledUp = nullptr) = 0;
+
+  /**
+   * Asks the RollupListener if it should rollup on mouse wheel events
+   */
+  virtual bool ShouldRollupOnMouseWheelEvent() = 0;
+
+  /**
+   * Asks the RollupListener if it should consume mouse wheel events
+   */
+  virtual bool ShouldConsumeOnMouseWheelEvent() = 0;
+
+  /**
+   * Asks the RollupListener if it should rollup on mouse activate, eg. X-Mouse
+   */
+  virtual bool ShouldRollupOnMouseActivate() = 0;
+
+  /*
+   * Retrieve the widgets for open menus and store them in the array
+   * aWidgetChain. The number of menus of the same type should be returned,
+   * for example, if a context menu is open, return only the number of menus
+   * that are part of the context menu chain. This allows closing up only
+   * those menus in different situations. The returned value should be exactly
+   * the same number of widgets added to aWidgetChain.
+   */
+  virtual uint32_t GetSubmenuWidgetChain(
+      nsTArray<nsIWidget*>* aWidgetChain) = 0;
+
+  virtual nsIWidget* GetRollupWidget() = 0;
+
+  /**
+   * If a native menu is currently shown, closes the menu.
+   * Returns true if a native menu was open.
+   */
+  virtual bool RollupNativeMenu() { return false; }
+};
+
+#endif /* __nsIRollupListener_h__ */
diff --git a/widget/nsIScreen.idl b/widget/nsIScreen.idl
new file mode 100644
index 0000000000..af8371edb3
--- /dev/null
+++ b/widget/nsIScreen.idl
@@ -0,0 +1,127 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+%{C++
+#include "Units.h"
+
+namespace mozilla::dom {
+// TODO(zrhoffman, bug 1444515): ScreenColorGamut should be forward-declared
+// using `webidl` once the webidl identifier supports enums.
+enum class ScreenColorGamut : uint8_t;
+}  // namespace mozilla::dom
+
+/**
+ * The display type of nsIScreen belongs to.
+ */
+enum class DisplayType: int32_t {
+  DISPLAY_PRIMARY,  // primary screen
+  DISPLAY_EXTERNAL, // wired displays, such as HDMI, DisplayPort, etc.
+  DISPLAY_VIRTUAL   // wireless displays, such as Chromecast, WiFi-Display, etc.
+};
+%}
+
+native ScreenColorGamut(mozilla::dom::ScreenColorGamut);
+
+[scriptable, builtinclass, uuid(826e80c8-d70f-42e2-8aa9-82c05f2a370a)]
+interface nsIScreen : nsISupports
+{
+  /**
+   * These report screen dimensions in (screen-specific) device pixels
+   */
+  void GetRect(out long left, out long top, out long width, out long height);
+  void GetAvailRect(out long left, out long top, out long width, out long height);
+
+%{C++
+  mozilla::LayoutDeviceIntRect GetRect() {
+    int32_t left = 0, top = 0, width = 0, height = 0;
+    GetRect(&left, &top, &width, &height);
+    return {left, top, width, height};
+  }
+
+  mozilla::LayoutDeviceIntRect GetAvailRect() {
+    int32_t left = 0, top = 0, width = 0, height = 0;
+    GetAvailRect(&left, &top, &width, &height);
+    return {left, top, width, height};
+  }
+%}
+
+  /**
+   * And these report in desktop pixels
+   */
+  void GetRectDisplayPix(out long left, out long top, out long width, out long height);
+  void GetAvailRectDisplayPix(out long left, out long top, out long width, out long height);
+
+%{C++
+  mozilla::DesktopIntRect GetRectDisplayPix() {
+    int32_t left = 0, top = 0, width = 0, height = 0;
+    GetRectDisplayPix(&left, &top, &width, &height);
+    return {left, top, width, height};
+  }
+
+  mozilla::DesktopIntRect GetAvailRectDisplayPix() {
+    int32_t left = 0, top = 0, width = 0, height = 0;
+    GetAvailRectDisplayPix(&left, &top, &width, &height);
+    return {left, top, width, height};
+  }
+%}
+
+  [infallible] readonly attribute long pixelDepth;
+  [infallible] readonly attribute long colorDepth;
+  /**
+   * ScreenColorGamut is native type, which cannot be declared [infallible].
+   */
+  readonly attribute ScreenColorGamut colorGamut;
+
+  /**
+   * The number of device pixels per desktop pixel for this screen (for
+   * hidpi configurations where there may be multiple device pixels per
+   * desktop px and/or per CSS px).
+   *
+   * This seems poorly named (something like devicePixelsPerDesktopPixel
+   * would be more accurate/explicit), but given that it is exposed to
+   * front-end code and may also be used by add-ons, it's probably not
+   * worth the disruption of changing it.
+   *
+   * Returns 1.0 if HiDPI mode is disabled or unsupported, or if the
+   * host OS uses device pixels as its desktop pixel units (e.g. Windows 7 or
+   * GTK/X11). Per-monitor DPI is available in Windows 8.1+, GTK/Wayland or
+   * macOS.
+   */
+  [infallible] readonly attribute double contentsScaleFactor;
+
+  /**
+   * The default number of device pixels per unscaled CSS pixel for this
+   * screen. This is probably what contentsScaleFactor originally meant
+   * to be, prior to confusion between CSS pixels and desktop pixel units.
+   */
+  [infallible] readonly attribute double defaultCSSScaleFactor;
+
+%{C++
+
+  mozilla::DesktopToLayoutDeviceScale GetDesktopToLayoutDeviceScale() {
+    return mozilla::DesktopToLayoutDeviceScale(GetContentsScaleFactor());
+  }
+
+  mozilla::CSSToLayoutDeviceScale GetCSSToLayoutDeviceScale() {
+    return mozilla::CSSToLayoutDeviceScale(GetDefaultCSSScaleFactor());
+  }
+
+  mozilla::CSSToDesktopScale GetCSSToDesktopScale() {
+    return GetCSSToLayoutDeviceScale() / GetDesktopToLayoutDeviceScale();
+  }
+
+%}
+  /**
+   * The DPI of the screen.
+   */
+  [infallible] readonly attribute float dpi;
+
+  /** The target screen refresh rate, in Hz, or 0 if unknown */
+  [infallible] readonly attribute long refreshRate;
+  [infallible] readonly attribute boolean isPseudoDisplay;
+};
diff --git a/widget/nsIScreenManager.idl b/widget/nsIScreenManager.idl
new file mode 100644
index 0000000000..9203d7891f
--- /dev/null
+++ b/widget/nsIScreenManager.idl
@@ -0,0 +1,36 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "nsIScreen.idl"
+
+%{C++
+#include "nsCOMPtr.h"
+%}
+
+[scriptable, uuid(e8a96e60-6b61-4a14-bacc-53891604b502)]
+interface nsIScreenManager : nsISupports
+{
+  // Returns the screen that contains the rectangle. If the rect overlaps
+  // multiple screens, it picks the screen with the greatest area of intersection.
+  //
+  // The coordinates are in pixels (not twips) and in screen coordinates.
+  nsIScreen screenForRect(in long left, in long top, in long width, in long height) ;
+
+%{C++
+  already_AddRefed<nsIScreen> ScreenForRect(const mozilla::DesktopIntRect& aRect) {
+    nsCOMPtr<nsIScreen> screen;
+    ScreenForRect(aRect.x, aRect.y, aRect.width, aRect.height, getter_AddRefs(screen));
+    return screen.forget();
+  }
+%}
+
+  // The screen with the menubar/taskbar. This shouldn't be needed very often.
+  readonly attribute nsIScreen primaryScreen;
+
+  // The total number of pixels across all monitors.
+  readonly attribute int64_t totalScreenPixels;
+};
diff --git a/widget/nsISharePicker.idl b/widget/nsISharePicker.idl
new file mode 100644
index 0000000000..34c7f18d0e
--- /dev/null
+++ b/widget/nsISharePicker.idl
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIURI;
+
+interface mozIDOMWindowProxy;
+
+[scriptable, uuid(1201d357-8417-4926-a694-e6408fbedcf8)]
+interface nsISharePicker : nsISupports
+{
+  /**
+   * Initialize the share picker widget.
+   * @param nsIDOMWindow openerWindow.
+   */
+  void init(in mozIDOMWindowProxy openerWindow);
+
+  /**
+   * Returns the parent window this was initialized with.
+   */
+  readonly attribute mozIDOMWindowProxy openerWindow;
+
+  /**
+   * XPCOM Analog of navigator.share() as per:
+   * https://w3c.github.io/web-share/#share-method
+   */
+  Promise share(in AUTF8String title, in AUTF8String text, in nsIURI url);
+};
diff --git a/widget/nsISound.idl b/widget/nsISound.idl
new file mode 100644
index 0000000000..8b4a2f29c0
--- /dev/null
+++ b/widget/nsISound.idl
@@ -0,0 +1,40 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIURL;
+
+[scriptable, uuid(C3C28D92-A17F-43DF-976D-4EEAE6F995FC)]
+interface nsISound : nsISupports
+{
+  void play(in nsIURL aURL);
+  void beep();
+
+  /**
+    * Not strictly necessary, but avoids delay before first sound.
+    * The various methods on nsISound call Init() if they need to.
+    */
+  void init();
+
+  /**
+   * In some situations, playEventSound will be called.  Then, each
+   * implementations will play a system sound for the event if it's necessary.
+   *
+   * NOTE: Don't change these values because they are used in
+   * nsPIPromptService.idl. So, if they are changed, that makes big impact for
+   * the embedders.
+   */
+  const unsigned long EVENT_NEW_MAIL_RECEIVED           = 0;
+  const unsigned long EVENT_ALERT_DIALOG_OPEN           = 1;
+  const unsigned long EVENT_CONFIRM_DIALOG_OPEN         = 2;
+  const unsigned long EVENT_PROMPT_DIALOG_OPEN          = 3;
+  const unsigned long EVENT_SELECT_DIALOG_OPEN          = 4;
+  const unsigned long EVENT_MENU_EXECUTE                = 5;
+  const unsigned long EVENT_MENU_POPUP                  = 6;
+  const unsigned long EVENT_EDITOR_MAX_LEN              = 7;
+  void playEventSound(in unsigned long aEventId);
+};
diff --git a/widget/nsIStandaloneNativeMenu.idl b/widget/nsIStandaloneNativeMenu.idl
new file mode 100644
index 0000000000..b995f1f8b9
--- /dev/null
+++ b/widget/nsIStandaloneNativeMenu.idl
@@ -0,0 +1,55 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+webidl Element;
+
+/**
+ * Platform-independent interface to platform native menu objects.
+ */
+
+[scriptable, uuid(7F7201EB-510C-4CEF-BDF0-04A15A7A4A8C)]
+interface nsIStandaloneNativeMenu : nsISupports
+{
+  /**
+   * Initialize the native menu using given XUL DOM element.
+   *
+   * @param aDOMElement A XUL DOM element of tag type |menu| or |menupopup|.
+   */
+  void init(in Element aElement);
+
+  /**
+   * This method must be called before the menu is opened and displayed to the
+   * user. It allows the platform code to update the menu and also determine
+   * whether the menu should even be shown.
+   *
+   * @return true if the menu can be shown, false if it should not be shown
+   */
+  boolean menuWillOpen();
+
+  /**
+   * Activate the native menu item specified by |anIndexString|. This method
+   * is intended to be used by the test suite.
+   *
+   * @param anIndexString string containing a list of indices separated by
+   *        pipe ('|') characters
+   */
+  void activateNativeMenuItemAt(in AString anIndexString);
+
+  /**
+   * Force an update of the native menu item specified by |anIndexString|. This
+   * method is intended to be used by the test suite.
+   *
+   * @param anIndexString string containing a list of indices separated by
+   *        pipe ('|') characters
+   */
+  void forceUpdateNativeMenuAt(in AString anIndexString);
+
+  /**
+   * Print information about the menu structure to stdout. Only used for
+   * debugging.
+   */
+  void dump();
+};
diff --git a/widget/nsISystemStatusBar.idl b/widget/nsISystemStatusBar.idl
new file mode 100644
index 0000000000..51aa457a08
--- /dev/null
+++ b/widget/nsISystemStatusBar.idl
@@ -0,0 +1,36 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+webidl Element;
+
+/**
+ * Allow applications to interface with the Mac OS X system status bar.
+ */
+
+[scriptable, uuid(24493180-ee81-4b7c-8b17-9e69480b7b8a)]
+interface nsISystemStatusBar : nsISupports
+{
+  /**
+   * Add an item to the system status bar. Each item can only be present once,
+   * subsequent addItem calls with the same element will be ignored.
+   * The system status bar holds a strong reference to the added XUL menu
+   * element and the item will stay in the status bar until it is removed via
+   * a call to removeItem, or until the process shuts down.
+   * @param aDOMMenuElement A XUL menu element that contains a XUL menupopup
+   *                        with regular menu content. The menu's icon is put
+   *                        into the system status bar; clicking it will open
+   *                        a menu with the contents of the menupopup.
+   *                        The menu label is not shown.
+   */
+  void addItem(in Element aMenuElement);
+
+  /**
+   * Remove a previously-added item from the menu bar. Calling this with an
+   * element that has not been added before will be silently ignored.
+   * @param aDOMMenuElement The XUL menu element that you called addItem with.
+   */
+  void removeItem(in Element aMenuElement);
+};
diff --git a/widget/nsITaskbarOverlayIconController.idl b/widget/nsITaskbarOverlayIconController.idl
new file mode 100644
index 0000000000..f11cf16ed0
--- /dev/null
+++ b/widget/nsITaskbarOverlayIconController.idl
@@ -0,0 +1,39 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface imgIContainer;
+
+/**
+ * Starting in Windows 7, applications can display an overlay on the icon in
+ * the taskbar. This class wraps around the native functionality to do this.
+ */
+[scriptable, uuid(b1858889-a698-428a-a14b-b5d60cff6de2)]
+interface nsITaskbarOverlayIconController : nsISupports
+{
+  /**
+   * Sets the overlay icon and its corresponding alt text.
+   *
+   * @param statusIcon The handle to the overlay icon. The icon will be scaled
+   *                   to the small icon size (16x16 at 96 dpi). Can be null, in
+   *                   which case if the taskbar button represents a single window
+   *                   the icon is removed.
+   * @param statusDescription The alt text version of the information
+   *                          conveyed by the overlay, for accessibility
+   *                          purposes.
+   *
+   * @note The behavior for window groups is managed by Windows.
+   * - If an overlay icon is set for any window in a window group and another
+   *   overlay icon is already applied to the corresponding taskbar button, that
+   *   existing overlay is replaced.
+   * - If null is passed in to replace the overlay currently being displayed,
+   *   and if a previous overlay set for a different window in the group is
+   *   still available, then that previous overlay is displayed.
+   */
+  void setOverlayIcon(in imgIContainer statusIcon,
+                      in AString statusDescription);
+};
diff --git a/widget/nsITaskbarPreview.idl b/widget/nsITaskbarPreview.idl
new file mode 100644
index 0000000000..9bb5f079e7
--- /dev/null
+++ b/widget/nsITaskbarPreview.idl
@@ -0,0 +1,70 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "nsIBaseWindow.idl"
+
+interface nsITaskbarPreviewController;
+
+/**
+ * nsITaskbarPreview
+ *
+ * Common interface for both window and tab taskbar previews. This interface
+ * cannot be instantiated directly.
+ *
+ */
+[scriptable, uuid(CBFDF766-D002-403B-A3D9-B091C9AD465B)]
+interface nsITaskbarPreview : nsISupports
+{
+  /**
+   * The controller for this preview. A controller is required to provide
+   * the behavior and appearance of the taskbar previews. It is responsible for
+   * determining the size and contents of the preview, which buttons are
+   * displayed and how the application responds to user actions on the preview.
+   *
+   * Neither preview makes full use of the controller. See the documentation
+   * for nsITaskbarWindowPreview and nsITaskbarTabPreview for details on which
+   * controller methods are used.
+   *
+   * The controller is not allowed to be null.
+   *
+   * @see nsITaskbarPreviewController
+   */
+  attribute nsITaskbarPreviewController controller;
+
+  /**
+   * The tooltip displayed above the preview when the user hovers over it
+   *
+   * Default: an empty string
+   */
+  attribute AString tooltip;
+
+  /**
+   * Whether or not the preview is visible.
+   *
+   * Changing this option is expensive for tab previews since toggling this
+   * option will destroy/create the proxy window and its registration with the
+   * taskbar. If any step of that fails, an exception will be thrown.
+   *
+   * For window previews, this operation is very cheap.
+   *
+   * Default: false
+   */
+  attribute boolean visible;
+
+  /**
+   * Gets/sets whether or not the preview is marked active (selected) in the
+   * taskbar.
+   */
+  attribute boolean active;
+
+  /**
+   * Invalidates the taskbar's cached image of this preview, forcing a redraw
+   * if necessary
+   */
+  void invalidate();
+};
diff --git a/widget/nsITaskbarPreviewButton.idl b/widget/nsITaskbarPreviewButton.idl
new file mode 100644
index 0000000000..79ad36699a
--- /dev/null
+++ b/widget/nsITaskbarPreviewButton.idl
@@ -0,0 +1,62 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface imgIContainer;
+
+/**
+ * nsITaskbarPreviewButton
+ *
+ * Provides access to a window preview's toolbar button's properties.
+ */
+[scriptable, uuid(CED8842D-FE37-4767-9A8E-FDFA56510C75)]
+interface nsITaskbarPreviewButton : nsISupports
+{
+  /**
+   * The button's tooltip.
+   *
+   * Default: an empty string
+   */
+  attribute AString tooltip;
+
+  /**
+   * True if the array of previews should be dismissed when this button is clicked.
+   *
+   * Default: false
+   */
+  attribute boolean dismissOnClick;
+
+  /**
+   * True if the taskbar should draw a border around this button's image.
+   *
+   * Default: true
+   */
+  attribute boolean hasBorder;
+
+  /**
+   * True if the button is disabled. This is not the same as visible.
+   *
+   * Default: false
+   */
+  attribute boolean disabled;
+
+  /**
+   * The icon used for the button.
+   *
+   * Default: null
+   */
+  attribute imgIContainer image;
+
+  /**
+   * True if the button is shown. Buttons that are invisible do not
+   * participate in the layout of buttons underneath the preview.
+   *
+   * Default: false
+   */
+  attribute boolean visible;
+};
diff --git a/widget/nsITaskbarPreviewController.idl b/widget/nsITaskbarPreviewController.idl
new file mode 100644
index 0000000000..4920687dfb
--- /dev/null
+++ b/widget/nsITaskbarPreviewController.idl
@@ -0,0 +1,103 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIDocShell;
+interface nsITaskbarPreview;
+interface nsITaskbarPreviewButton;
+
+/**
+ * nsITaskbarPreviewCallback
+ *
+ * Provides an interface for async image result callbacks. See
+ * nsITaskbarPreviewController request apis below.
+ */
+[scriptable, function, uuid(f3744696-320d-4804-9c27-6a84c29acaa6)]
+interface nsITaskbarPreviewCallback : nsISupports
+{
+  void done(in nsISupports aCanvas, in boolean aDrawBorder);
+};
+
+/**
+ * nsITaskbarPreviewController
+ *
+ * nsITaskbarPreviewController provides the behavior for the taskbar previews.
+ * Its methods and properties are used by nsITaskbarPreview. Clients are
+ * intended to provide their own implementation of this interface. Depending on
+ * the interface the controller is attached to, only certain methods/attributes
+ * are required to be implemented.
+ */
+[scriptable, uuid(8b427646-e446-4941-ae0b-c1122a173a68)]
+interface nsITaskbarPreviewController : nsISupports
+{
+  /**
+   * The width of the preview image. This value is allowed to change at any
+   * time. See requestPreview for more information.
+   */
+  readonly attribute unsigned long width;
+
+  /**
+   * The height of the preview image. This value is allowed to change at any
+   * time.  See requestPreview for more information.
+   */
+  readonly attribute unsigned long height;
+
+  /**
+   * The aspect ratio of the thumbnail - this does not need to match the ratio
+   * of the preview. This value is allowed to change at any time. See
+   * requestThumbnail for more information.
+   */
+  readonly attribute float thumbnailAspectRatio;
+
+  /**
+   * Invoked by nsITaskbarPreview when it needs to render the preview.
+   *
+   * @param aCallback Async callback the controller should invoke once
+   * the thumbnail is rendered. aCallback receives as its only parameter
+   * a canvas containing the preview image.
+   */
+  void requestPreview(in nsITaskbarPreviewCallback aCallback);
+
+  /**
+   * Note: it is guaranteed that width/height == thumbnailAspectRatio
+   * (modulo rounding errors)
+   *
+   * Also note that the context is not attached to a canvas element.
+   *
+   * @param aCallback Async callback the controller should invoke once
+   * the thumbnail is rendered. aCallback receives as its only parameter
+   * a canvas containing the thumbnail image. Canvas dimensions should
+   * match the requested width or height otherwise setting the thumbnail
+   * will fail.
+   * @param width The width of the requested thumbnail
+   * @param height The height of the requested thumbnail
+   */
+  void requestThumbnail(in nsITaskbarPreviewCallback aCallback,
+                        in unsigned long width, in unsigned long height);
+
+  /**
+   * Invoked when the user presses the close button on the tab preview.
+   */
+  void onClose();
+
+  /**
+   * Invoked when the user clicks on the tab preview.
+   *
+   * @return true if the top level window corresponding to the preview should
+   *         be activated, false if activation is not accepted.
+   */
+  boolean onActivate();
+
+  /**
+   * Invoked when one of the buttons on the window preview's toolbar is pressed.
+   *
+   * @param button The button that was pressed. This can be compared with the
+   *               buttons returned by nsITaskbarWindowPreview.getButton.
+   */
+  void onClick(in nsITaskbarPreviewButton button);
+};
diff --git a/widget/nsITaskbarProgress.idl b/widget/nsITaskbarProgress.idl
new file mode 100644
index 0000000000..d81179d311
--- /dev/null
+++ b/widget/nsITaskbarProgress.idl
@@ -0,0 +1,58 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "nsIBaseWindow.idl"
+
+typedef long nsTaskbarProgressState;
+
+/**
+ * Starting in Windows 7, applications can display a progress notification in
+ * the taskbar. This class wraps around the native functionality to do this.
+ */
+[scriptable, uuid(23ac257d-ef3c-4033-b424-be7fef91a86c)]
+interface nsITaskbarProgress : nsISupports
+{
+  /**
+   * Stop displaying progress on the taskbar button. This should be used when
+   * the operation is complete or cancelled.
+   */
+  const nsTaskbarProgressState STATE_NO_PROGRESS   = 0;
+
+  /**
+   * Display a cycling, indeterminate progress bar.
+   */
+  const nsTaskbarProgressState STATE_INDETERMINATE = 1;
+
+  /**
+   * Display a determinate, normal progress bar.
+   */
+  const nsTaskbarProgressState STATE_NORMAL        = 2;
+
+  /**
+   * Display a determinate, error progress bar.
+   */
+  const nsTaskbarProgressState STATE_ERROR         = 3;
+
+  /**
+   * Display a determinate progress bar indicating that the operation has
+   * paused.
+   */
+  const nsTaskbarProgressState STATE_PAUSED        = 4;
+
+  /**
+   * Sets the taskbar progress state and value for this window. The currentValue
+   * and maxValue parameters are optional and should be supplied when |state|
+   * is one of STATE_NORMAL, STATE_ERROR or STATE_PAUSED.
+   *
+   * @throws NS_ERROR_INVALID_ARG if state is STATE_NO_PROGRESS or
+   *         STATE_INDETERMINATE, and either currentValue or maxValue is not 0.
+   * @throws NS_ERROR_ILLEGAL_VALUE if currentValue is greater than maxValue.
+   */
+  void setProgressState(in nsTaskbarProgressState state,
+                        [optional] in unsigned long long currentValue,
+                        [optional] in unsigned long long maxValue);
+};
diff --git a/widget/nsITaskbarTabPreview.idl b/widget/nsITaskbarTabPreview.idl
new file mode 100644
index 0000000000..47520e38a6
--- /dev/null
+++ b/widget/nsITaskbarTabPreview.idl
@@ -0,0 +1,62 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsITaskbarPreview.idl"
+interface imgIContainer;
+
+/*
+ * nsITaskbarTabPreview
+ *
+ * This interface controls tab preview-specific behavior. Creating an
+ * nsITaskbarTabPreview for a window will hide that window's
+ * nsITaskbarWindowPreview in the taskbar - the native API performs this
+ * unconditionally. When there are no more tab previews for a window, the
+ * nsITaskbarWindowPreview will automatically become visible again.
+ *
+ * An application may have as many tab previews per window as memory allows.
+ *
+ */
+[scriptable, builtinclass, uuid(11E4C8BD-5C2D-4E1A-A9A1-79DD5B0FE544)]
+interface nsITaskbarTabPreview : nsITaskbarPreview
+{
+  /**
+   * The title displayed above the thumbnail
+   *
+   * Default: an empty string
+   */
+  attribute AString title;
+
+  /**
+   * The icon displayed next to the title in the preview
+   *
+   * Default: null
+   */
+  attribute imgIContainer icon;
+
+  /**
+   * Rearranges the preview relative to another tab preview from the same window
+   * @param aNext The preview to the right of this one. A value of null
+   *              indicates that the preview is the rightmost one.
+   */
+  void move(in nsITaskbarTabPreview aNext);
+
+  /**
+   * Used internally to grab the handle to the proxy window.
+   */
+  [notxpcom]
+  nativeWindow GetHWND();
+
+  /**
+   * Used internally to ensure that the taskbar knows about this preview. If a
+   * preview is not registered, then the API call to set its sibling (via move)
+   * will silently fail.
+   *
+   * This method is only invoked when it is safe to make taskbar API calls.
+   */
+  [notxpcom]
+  void EnsureRegistration();
+};
diff --git a/widget/nsITaskbarWindowPreview.idl b/widget/nsITaskbarWindowPreview.idl
new file mode 100644
index 0000000000..c73e8b696e
--- /dev/null
+++ b/widget/nsITaskbarWindowPreview.idl
@@ -0,0 +1,69 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsITaskbarPreview.idl"
+interface nsITaskbarPreviewButton;
+
+/*
+ * nsITaskbarWindowPreview
+ *
+ * This interface represents the preview for a window in the taskbar. By
+ * default, Windows implements much of the behavior for applications by
+ * default. The primary purpose of this interface is to allow Gecko
+ * applications to take control over parts of the preview. Some parts are not
+ * controlled through this interface: the title and icon of the preview match
+ * the title and icon of the window always.
+ *
+ * By default, Windows takes care of drawing the thumbnail and preview for the
+ * application however if enableCustomDrawing is set to true, then the
+ * controller will start to receive requestPreview and requestThumbnail calls
+ * as well as reads on the thumbnailAspectRatio, width and height properties.
+ *
+ * By default, nsITaskbarWindowPreviews are visible. When made invisible, the
+ * window disappears from the list of windows in the taskbar for the
+ * application.
+ *
+ * If the window has any visible nsITaskbarTabPreviews, then the
+ * nsITaskbarWindowPreview for the corresponding window is automatically
+ * hidden. This is not reflected in the visible property. Note that other parts
+ * of the system (such as alt-tab) may still request thumbnails and/or previews
+ * through the nsITaskbarWindowPreview's controller.
+ *
+ * nsITaskbarWindowPreview will never invoke the controller's onClose or
+ * onActivate methods since handling them may conflict with other internal
+ * Gecko state and there is existing infrastructure in place to allow clients
+ * to handle those events
+ *
+ * Window previews may have a toolbar with up to 7 buttons. See
+ * nsITaskbarPreviewButton for more information about button properties.
+ */
+[scriptable, uuid(EC67CC57-342D-4064-B4C6-74A375E07B10)]
+interface nsITaskbarWindowPreview : nsITaskbarPreview
+{
+  /**
+   * Max 7 buttons per preview per the Windows Taskbar API
+   */
+  const long NUM_TOOLBAR_BUTTONS = 7;
+
+  /**
+   * Gets the nth button for the preview image. By default, all of the buttons
+   * are invisible.
+   *
+   * @see nsITaskbarPreviewButton
+   *
+   * @param index The index into the button array. Must be >= 0 and <
+   *              MAX_TOOLBAR_BUTTONS.
+   */
+  nsITaskbarPreviewButton getButton(in unsigned long index);
+
+  /**
+   * Enables/disables custom drawing of thumbnails and previews
+   *
+   * Default value: false
+   */
+  attribute boolean enableCustomDrawing;
+};
diff --git a/widget/nsITouchBarHelper.idl b/widget/nsITouchBarHelper.idl
new file mode 100644
index 0000000000..62d2e8593b
--- /dev/null
+++ b/widget/nsITouchBarHelper.idl
@@ -0,0 +1,65 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIArray.idl"
+#include "nsISupports.idl"
+#include "nsITouchBarInput.idl"
+
+webidl Document;
+
+/**
+ * Back-to-frontend communication for the Touch Bar
+ */
+[scriptable, uuid(ea109912-3acc-48de-b679-c23b6a122da5)]
+interface nsITouchBarHelper : nsISupports
+{
+  /**
+   * Returns the active browser's URL.
+   */
+  readonly attribute AString activeUrl;
+
+  /**
+   * Return the active browser's page title.
+   */
+  readonly attribute AString activeTitle;
+
+  /**
+   * Return true if the Urlbar has focus.
+   */
+  readonly attribute boolean isUrlbarFocused;
+
+  /**
+   * Toggles Urlbar focus.
+   */
+  void toggleFocusUrlbar();
+
+  /**
+   * Unfocuses the Urlbar.
+   */
+  void unfocusUrlbar();
+
+  /**
+   * Returns all available Touch Bar Inputs in an nsIArray
+   * of nsITouchBarInput objects.
+   */
+  attribute nsIArray allItems;
+
+  /**
+   * The context in which this nsITouchBarHelper exists. Required to create
+   * an imgLoader to load our SVG icons.
+   */
+  readonly attribute Document document;
+
+  /**
+   * Returns the requested TouchBarInput.
+   * Exposed for testing.
+   */
+  nsITouchBarInput getTouchBarInput(in string aInputName);
+
+  /**
+   * Inserts a search restriction string in the Urlbar.
+   * Exposed for testing.
+   */
+  void insertRestrictionInUrlbar(in string aToken);
+};
diff --git a/widget/nsITouchBarInput.idl b/widget/nsITouchBarInput.idl
new file mode 100644
index 0000000000..0c9c3b0b1a
--- /dev/null
+++ b/widget/nsITouchBarInput.idl
@@ -0,0 +1,78 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIArray.idl"
+#include "nsISupports.idl"
+#include "nsIURI.idl"
+
+[scriptable, function, uuid(001ab07c-1b3a-4dbf-a657-fada0065ff55)]
+interface nsITouchBarInputCallback : nsISupports
+{
+  void onCommand();
+};
+
+/**
+ * Implements an input to be registered on the Mac Touch Bar.
+ */
+
+[scriptable, uuid(77441d17-f29c-49d7-982f-f20a5ab5a900)]
+interface nsITouchBarInput : nsISupports
+{
+  readonly attribute AString key;
+
+  /**
+   * The lookup key for the button's localized text title.
+   */
+  attribute AString title;
+
+  /**
+   * The URI of an icon file.
+   */
+  attribute nsIURI image;
+
+  /**
+   * The type of the input.
+   * Takes one of:
+   *   `button`:
+   *     A standard button.
+   *     If an image is available, only the image is displayed.
+   *   `mainButton`:
+   *     An extra-wide button. Displays both the image and title.
+   *   `scrubber`:
+   *     A Scrubber element. Not yet implemented, except in the case of Apple's
+   *     pre-built Share scrubber.
+   *   `popover`:
+   *     An element that displays a new instance of nsTouchBar when tapped.
+   *     The elements in the new Touch Bar should be defined in the
+   *     input's `children` property.
+   *   `label`:
+   *     A text label.
+   *   `scrollView`:
+   *     Contains several buttons, defined in the input's `children` property.
+   *     The user can scroll through the buttons.
+   */
+  attribute AString type;
+
+  /**
+   * A callback function to be invoked when an element is touched.
+   */
+  attribute nsITouchBarInputCallback callback;
+
+  /**
+   * A hexadecimal uint32_t specifying the input's
+   * background color. If omitted, the default background color is used.
+   */
+  attribute uint32_t color;
+
+  /**
+   * If `true`, the Touch Bar input is greyed out and inoperable.
+   */
+  attribute boolean disabled;
+
+  /**
+   * An array containing an input's children.
+   * Available for  type = ("scrollView" || "popover").
+   */
+  attribute nsIArray children;
+};
diff --git a/widget/nsITouchBarUpdater.idl b/widget/nsITouchBarUpdater.idl
new file mode 100644
index 0000000000..f804191a08
--- /dev/null
+++ b/widget/nsITouchBarUpdater.idl
@@ -0,0 +1,42 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIArray.idl"
+#include "nsIBaseWindow.idl"
+#include "nsISupports.idl"
+#include "nsITouchBarInput.idl"
+
+/**
+ * Front-to-backend communication to keep Touch Bar updated
+ */
+[scriptable, uuid(38f396e2-93c9-4a77-aaf7-2d50b9962186)]
+interface nsITouchBarUpdater : nsISupports
+{
+  /**
+   * Updates an array of nsITouchBarInputs in the specified window.
+   */
+  void updateTouchBarInputs(in nsIBaseWindow aWindow, in Array<nsITouchBarInput> aInputs);
+
+  /**
+   * Enter the native Touch Bar customization window.
+   */
+  void enterCustomizeMode();
+
+  /**
+   * Checks if the user is using a Touch Bar-compatible Mac.
+   */
+  boolean isTouchBarInitialized();
+
+  /**
+   * Sets whether the Touch Bar is initialized.
+   * NOTE: This method is for internal unit tests only! Normally, the system
+   * sets this value after a Touch Bar is initialized on compatible Macs.
+   */
+  void setTouchBarInitialized(in boolean aIsInitialized);
+
+  /**
+   * If aShowing is true, aPopover is shown. Otherwise, it is hidden.
+   */
+  void showPopover(in nsIBaseWindow aWindow, in nsITouchBarInput aPopover, in boolean aShowing);
+};
diff --git a/widget/nsITransferable.idl b/widget/nsITransferable.idl
new file mode 100644
index 0000000000..0a8419c4bb
--- /dev/null
+++ b/widget/nsITransferable.idl
@@ -0,0 +1,225 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIArray.idl"
+#include "nsISupports.idl"
+#include "nsIFormatConverter.idl"
+#include "nsIContentPolicy.idl"
+
+interface nsICookieJarSettings;
+interface nsIPrincipal;
+interface nsIReferrerInfo;
+
+%{ C++
+
+// Internal formats must have their second part starting with 'x-moz-',
+// for example text/x-moz-internaltype. These cannot be assigned by
+// unprivileged content but all other types can.
+#define kInternal_Mimetype_Prefix   u"/x-moz-"_ns
+
+// these probably shouldn't live here, but in some central repository shared
+// by the entire app.
+#define kTextMime                   "text/plain"
+#define kRTFMime                    "text/rtf"
+#define kMozTextInternal            "text/x-moz-text-internal"  // text data which isn't suppoed to be parsed by other apps.
+#define kHTMLMime                   "text/html"
+#define kAOLMailMime                "AOLMAIL"
+#define kPNGImageMime               "image/png"
+#define kJPEGImageMime              "image/jpeg"
+#define kJPGImageMime               "image/jpg"
+#define kGIFImageMime               "image/gif"
+#define kFileMime                   "application/x-moz-file"
+
+#define kURLMime                    "text/x-moz-url"        // data contains url\ntitle
+#define kURLDataMime                "text/x-moz-url-data"   // data contains url only
+#define kURLDescriptionMime         "text/x-moz-url-desc"   // data contains description
+#define kURLPrivateMime             "text/x-moz-url-priv"   // same as kURLDataMime but for private uses
+#define kNativeImageMime            "application/x-moz-nativeimage"
+#define kNativeHTMLMime             "application/x-moz-nativehtml"
+
+// These are used to indicate the context for a fragment of HTML source, such
+// that some parent structure and style can be preserved. kHTMLContext
+// contains the serialized ancestor elements, whereas kHTMLInfo are numbers
+// identifying where in the context the fragment was from.
+#define kHTMLContext   "text/_moz_htmlcontext"
+#define kHTMLInfo      "text/_moz_htmlinfo"
+
+// Holds the MIME type from the image request. This is used to ensure the
+// local application handler for the request's MIME type accepts images with
+// the given filename extension (from kFilePromiseDestFilename). When the
+// image is dragged out, we replace the extension with a compatible extension.
+#define kImageRequestMime           "text/x-moz-requestmime"
+
+// the source URL for a file promise
+#define kFilePromiseURLMime         "application/x-moz-file-promise-url"
+// the destination filename for a file promise
+#define kFilePromiseDestFilename    "application/x-moz-file-promise-dest-filename"
+// a dataless flavor used to interact with the OS during file drags
+#define kFilePromiseMime            "application/x-moz-file-promise"
+// a synthetic flavor, put into the transferable once we know the destination directory of a file drag
+#define kFilePromiseDirectoryMime   "application/x-moz-file-promise-dir"
+
+#define kCustomTypesMime "application/x-moz-custom-clipdata"
+
+#define kPDFJSMime "application/pdfjs"
+
+%}
+
+
+/**
+  * nsIFlavorDataProvider allows a flavor to 'promise' data later,
+  * supplying the data lazily.
+  *
+  * To use it, call setTransferData, passing the flavor string and
+  * a nsIFlavorDataProvider QI'd to nsISupports.
+  *
+  * When someone calls getTransferData later, if the data size is
+  * stored as 0, the nsISupports will be QI'd to nsIFlavorDataProvider,
+  * and its getFlavorData called.
+  *
+  */
+interface nsITransferable;
+interface nsILoadContext;
+
+[scriptable, uuid(7E225E5F-711C-11D7-9FAE-000393636592)]
+interface nsIFlavorDataProvider : nsISupports
+{
+
+  /**
+    * Retrieve the data from this data provider.
+    *
+    * @param  aTransferable (in parameter) the transferable we're being called for.
+    * @param  aFlavor (in parameter) the flavor of data to retrieve
+    * @param  aData the data. Some variant of class in nsISupportsPrimitives.idl
+    */
+  void getFlavorData(in nsITransferable aTransferable, in string aFlavor, out nsISupports aData);
+};
+
+
+[scriptable, builtinclass, uuid(97e0c418-1c1e-4106-bad1-9fcb11dff2fe)]
+interface nsITransferable : nsISupports
+{
+  /**
+   * Initializes a transferable object.  This should be called on all
+   * transferable objects.  Failure to do so will result in fatal assertions in
+   * debug builds.
+   *
+   * The load context is used to track whether the transferable is storing privacy-
+   * sensitive information.
+   *
+   * To get the appropriate load context in Javascript callers, one needs to get
+   * to the document that the transferable corresponds to, and then get the load
+   * context from the document like this:
+   *
+   * var loadContext = doc.defaultView.docShell
+   *                                  .QueryInterface(Ci.nsILoadContext);
+   *
+   * In C++ callers, if you have the corresponding document, you can just call
+   * Document::GetLoadContext to get to the load context object.
+   *
+   * @param aContext the load context associated with the transferable object.
+   *        This can be set to null if a load context is not available.
+   */
+  void init(in nsILoadContext aContext);
+
+  /**
+    * Computes a list of flavors that the transferable can export, either
+    * through intrinsic knowledge or output data converters.
+    */
+  Array<ACString> flavorsTransferableCanExport();
+
+  /**
+    * Given a flavor retrieve the data.
+    *
+    * @param  aFlavor (in parameter) the flavor of data to retrieve
+    * @param  aData the data. Some variant of class in nsISupportsPrimitives.idl
+    */
+  [must_use] void getTransferData(in string aFlavor, out nsISupports aData);
+
+  /**
+    * Returns the first flavor which has data.
+    *
+    * @param  aFlavor (out parameter) the flavor of data that was retrieved
+    * @param  aData the data. Some variant of class in nsISupportsPrimitives.idl
+    */
+  void getAnyTransferData(out ACString aFlavor, out nsISupports aData);
+
+    ///////////////////////////////
+    // Setter part of interface
+    ///////////////////////////////
+
+  /**
+    * Computes a list of flavors that the transferable can
+    * accept into it, either through intrinsic knowledge or input data converters.
+    *
+    */
+  Array<ACString> flavorsTransferableCanImport();
+
+  /**
+    * Sets the data in the transferable with the specified flavor. The transferable
+    * will maintain its own copy the data, so it is not necessary to do that beforehand.
+    *
+    * @param  aFlavor the flavor of data that is being set
+    * @param  aData the data, either some variant of class in nsISupportsPrimitives.idl,
+    *         an nsIFile, or an nsIFlavorDataProvider (see above)
+    */
+  void setTransferData(in string aFlavor, in nsISupports aData);
+
+  /**
+   * Removes the data from all flavors.
+   */
+  void clearAllData();
+
+  /**
+    * Add the data flavor, indicating that this transferable
+    * can receive this type of flavor
+    *
+    * @param  aDataFlavor a new data flavor to handle
+    */
+  void addDataFlavor ( in string aDataFlavor ) ;
+
+  /**
+    * Removes the data flavor matching the given one (string compare) and the data
+    * that goes along with it.
+    *
+    * @param  aDataFlavor a data flavor to remove
+    */
+  void removeDataFlavor ( in string aDataFlavor ) ;
+
+  attribute nsIFormatConverter converter;
+
+  /**
+   * Use of the SetIsPrivateData() method generated by isPrivateData attribute should
+   * be avoided as much as possible because the value set may not reflect the status
+   * of the context in which the transferable was created.
+   */
+  [notxpcom, nostdcall] attribute boolean isPrivateData;
+
+  /**
+   * The principal associated with this transferable. This could be either the
+   * node principal of the source DOM node from which this transferable was
+   * created, or the principal of the global from which this transferable was
+   * created.
+   * XXXedgar: Rename it to something more generic, bug 1867636.
+   */
+  [notxpcom, nostdcall] attribute nsIPrincipal requestingPrincipal;
+
+  /**
+   * the contentPolicyType for this transferable.
+   */
+  [notxpcom, nostdcall] attribute nsContentPolicyType contentPolicyType;
+
+  /**
+   * The cookieJarSettings of the source dom node this transferable was created
+   * from.
+   */
+  [notxpcom, nostdcall] attribute nsICookieJarSettings cookieJarSettings;
+
+  /**
+   * Used for initializing the referrer when downloading a file promise.
+   */
+  [notxpcom, nostdcall] attribute nsIReferrerInfo referrerInfo;
+};
diff --git a/widget/nsIUserIdleService.idl b/widget/nsIUserIdleService.idl
new file mode 100644
index 0000000000..3507232c36
--- /dev/null
+++ b/widget/nsIUserIdleService.idl
@@ -0,0 +1,86 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+interface nsIObserver;
+
+/**
+ * This interface lets you monitor how long the user has been 'idle',
+ * i.e. not used their mouse or keyboard. You can get the idle time directly,
+ * but in most cases you will want to register an observer for a predefined
+ * interval. The observer will get an 'idle' notification when the user is idle
+ * for that interval (or longer), and receive an 'active' notification when the
+ * user starts using their computer again.
+ */
+
+[scriptable, uuid(cc52f19a-63ae-4a1c-9cc3-e79eace0b471)]
+interface nsIUserIdleService : nsISupports
+{
+    /**
+     * The amount of time in milliseconds that has passed
+     * since the last user activity.
+     *
+     * If we do not have a valid idle time to report, 0 is returned
+     * (this can happen if the user never interacted with the browser
+     * at all, and if we are also unable to poll for idle time manually).
+     */
+    readonly attribute unsigned long idleTime;
+
+    /**
+     * Add an observer to be notified when the user idles for some period of
+     * time, and when they get back from that.
+     *
+     * @param observer the observer to be notified
+     * @param time the amount of time in seconds the user should be idle before
+     *             the observer should be notified.
+     *
+     * @note
+     * The subject of the notification the observer will get is always the
+     * nsIUserIdleService itself.
+     * When the user goes idle, the observer topic is "idle" and when he gets
+     * back, the observer topic is "active".
+     * The data param for the notification contains the current user idle time.
+     *
+     * @note
+     * You can add the same observer twice.
+     * @note
+     * Most implementations need to poll the OS for idle info themselves,
+     * meaning your notifications could arrive with a delay up to the length
+     * of the polling interval in that implementation.
+     * Current implementations use a delay of 5 seconds.
+     */
+    void addIdleObserver(in nsIObserver observer, in unsigned long time);
+
+    /**
+     * Remove an observer registered with addIdleObserver.
+     * @param observer the observer that needs to be removed.
+     * @param time the amount of time they were listening for.
+     * @note
+     * Removing an observer will remove it once, for the idle time you specify.
+     * If you have added an observer multiple times, you will need to remove it
+     * just as many times.
+     */
+    void removeIdleObserver(in nsIObserver observer, in unsigned long time);
+
+    /**
+     * If true, the idle service is temporarily disabled, and all idle events
+     * will be ignored.
+     *
+     * This should only be used in automation.
+     */
+    attribute boolean disabled;
+};
+
+%{C++
+    /**
+     * Observer topic notification for idle window: OBSERVER_TOPIC_IDLE.
+     * Observer topic notification for active window: OBSERVER_TOPIC_ACTIVE.
+     */
+
+    #define OBSERVER_TOPIC_IDLE "idle"
+    #define OBSERVER_TOPIC_ACTIVE "active"
+    #define OBSERVER_TOPIC_IDLE_DAILY "idle-daily"
+%}
diff --git a/widget/nsIUserIdleServiceInternal.idl b/widget/nsIUserIdleServiceInternal.idl
new file mode 100644
index 0000000000..044b95de3b
--- /dev/null
+++ b/widget/nsIUserIdleServiceInternal.idl
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIUserIdleService.idl"
+
+[scriptable, uuid(7b89a2e7-ed12-42e0-b86d-4984239abd7b)]
+interface nsIUserIdleServiceInternal : nsIUserIdleService
+{
+ /**
+   * "Resets the idle time to the value specified."
+   *
+   * @param idleDelta the time (in milliseconds) since the last user inter
+   *                  action
+   **/
+  void resetIdleTimeOut(in unsigned long idleDeltaInMS);
+};
diff --git a/widget/nsIWidget.h b/widget/nsIWidget.h
new file mode 100644
index 0000000000..81e952a8c6
--- /dev/null
+++ b/widget/nsIWidget.h
@@ -0,0 +1,2144 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsIWidget_h__
+#define nsIWidget_h__
+
+#include <cmath>
+#include <cstdint>
+#include "imgIContainer.h"
+#include "ErrorList.h"
+#include "Units.h"
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/gfx/Matrix.h"
+#include "mozilla/gfx/Rect.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/layers/ScrollableLayerGuid.h"
+#include "mozilla/layers/ZoomConstraints.h"
+#include "mozilla/image/Resolution.h"
+#include "mozilla/widget/IMEData.h"
+#include "nsCOMPtr.h"
+#include "nsColor.h"
+#include "nsDebug.h"
+#include "nsID.h"
+#include "nsIObserver.h"
+#include "nsISupports.h"
+#include "nsITheme.h"
+#include "nsITimer.h"
+#include "nsIWidgetListener.h"
+#include "nsRect.h"
+#include "nsSize.h"
+#include "nsStringFwd.h"
+#include "nsTArray.h"
+#include "nsTHashMap.h"
+#include "mozilla/widget/InitData.h"
+#include "nsXULAppAPI.h"
+
+// forward declarations
+class nsIBidiKeyboard;
+class nsIRollupListener;
+class nsIContent;
+class ViewWrapper;
+class nsIRunnable;
+
+namespace mozilla {
+enum class NativeKeyBindingsType : uint8_t;
+class VsyncDispatcher;
+class WidgetGUIEvent;
+class WidgetInputEvent;
+class WidgetKeyboardEvent;
+struct FontRange;
+enum class ColorScheme : uint8_t;
+enum class WindowButtonType : uint8_t;
+
+enum class WindowShadow : uint8_t {
+  None,
+  Menu,
+  Panel,
+  Tooltip,
+};
+
+#if defined(MOZ_WIDGET_ANDROID)
+namespace ipc {
+class Shmem;
+}
+#endif  // defined(MOZ_WIDGET_ANDROID)
+namespace dom {
+class BrowserChild;
+enum class CallerType : uint32_t;
+}  // namespace dom
+class WindowRenderer;
+namespace layers {
+class AsyncDragMetrics;
+class Compositor;
+class CompositorBridgeChild;
+struct FrameMetrics;
+class LayerManager;
+class WebRenderBridgeChild;
+}  // namespace layers
+namespace widget {
+class TextEventDispatcher;
+class TextEventDispatcherListener;
+class CompositorWidget;
+class CompositorWidgetInitData;
+class Screen;
+}  // namespace widget
+namespace wr {
+class DisplayListBuilder;
+class IpcResourceUpdateQueue;
+enum class RenderRoot : uint8_t;
+}  // namespace wr
+}  // namespace mozilla
+
+/**
+ * Callback function that processes events.
+ *
+ * The argument is actually a subtype (subclass) of WidgetEvent which carries
+ * platform specific information about the event. Platform specific code
+ * knows how to deal with it.
+ *
+ * The return value determines whether or not the default action should take
+ * place.
+ */
+typedef nsEventStatus (*EVENT_CALLBACK)(mozilla::WidgetGUIEvent* aEvent);
+
+// Hide the native window system's real window type so as to avoid
+// including native window system types and APIs. This is necessary
+// to ensure cross-platform code.
+typedef void* nsNativeWidget;
+
+/**
+ * Values for the GetNativeData function
+ */
+#define NS_NATIVE_WINDOW 0
+#define NS_NATIVE_GRAPHIC 1
+#define NS_NATIVE_WIDGET 3
+#define NS_NATIVE_REGION 5
+#define NS_NATIVE_OFFSETX 6
+#define NS_NATIVE_OFFSETY 7
+#define NS_NATIVE_SCREEN 9
+// The toplevel GtkWidget containing this nsIWidget:
+#define NS_NATIVE_SHELLWIDGET 10
+#define NS_NATIVE_OPENGL_CONTEXT 12
+// This is available only with GetNativeData() in parent process.  Anybody
+// shouldn't access this pointer as a valid pointer since the result may be
+// special value like NS_ONLY_ONE_NATIVE_IME_CONTEXT.  So, the result is just
+// an identifier of distinguishing a text composition is caused by which native
+// IME context.  Note that the result is only valid in the process.  So,
+// XP code should use nsIWidget::GetNativeIMEContext() instead of using this.
+#define NS_RAW_NATIVE_IME_CONTEXT 14
+#define NS_NATIVE_WINDOW_WEBRTC_DEVICE_ID 15
+#ifdef XP_WIN
+#  define NS_NATIVE_TSF_THREAD_MGR 100
+#  define NS_NATIVE_TSF_CATEGORY_MGR 101
+#  define NS_NATIVE_TSF_DISPLAY_ATTR_MGR 102
+#  define NS_NATIVE_ICOREWINDOW 103  // winrt specific
+#endif
+#if defined(MOZ_WIDGET_GTK)
+#  define NS_NATIVE_EGL_WINDOW 106
+#endif
+#ifdef MOZ_WIDGET_ANDROID
+#  define NS_JAVA_SURFACE 100
+#endif
+
+#define MOZ_WIDGET_MAX_SIZE 16384
+#define MOZ_WIDGET_INVALID_SCALE 0.0
+
+// Must be kept in sync with xpcom/rust/xpcom/src/interfaces/nonidl.rs
+#define NS_IWIDGET_IID                               \
+  {                                                  \
+    0x06396bf6, 0x2dd8, 0x45e5, {                    \
+      0xac, 0x45, 0x75, 0x26, 0x53, 0xb1, 0xc9, 0x80 \
+    }                                                \
+  }
+
+/**
+ * Cursor types.
+ */
+
+enum nsCursor {  ///(normal cursor,       usually rendered as an arrow)
+  eCursor_standard,
+  ///(system is busy,      usually rendered as a hourglass or watch)
+  eCursor_wait,
+  ///(Selecting something, usually rendered as an IBeam)
+  eCursor_select,
+  ///(can hyper-link,      usually rendered as a human hand)
+  eCursor_hyperlink,
+  ///(north/south/west/east edge sizing)
+  eCursor_n_resize,
+  eCursor_s_resize,
+  eCursor_w_resize,
+  eCursor_e_resize,
+  ///(corner sizing)
+  eCursor_nw_resize,
+  eCursor_se_resize,
+  eCursor_ne_resize,
+  eCursor_sw_resize,
+  eCursor_crosshair,
+  eCursor_move,
+  eCursor_help,
+  eCursor_copy,  // CSS3
+  eCursor_alias,
+  eCursor_context_menu,
+  eCursor_cell,
+  eCursor_grab,
+  eCursor_grabbing,
+  eCursor_spinning,
+  eCursor_zoom_in,
+  eCursor_zoom_out,
+  eCursor_not_allowed,
+  eCursor_col_resize,
+  eCursor_row_resize,
+  eCursor_no_drop,
+  eCursor_vertical_text,
+  eCursor_all_scroll,
+  eCursor_nesw_resize,
+  eCursor_nwse_resize,
+  eCursor_ns_resize,
+  eCursor_ew_resize,
+  eCursor_none,
+  // This one is used for array sizing, and so better be the last
+  // one in this list...
+  eCursorCount,
+
+  // ...except for this one.
+  eCursorInvalid = eCursorCount + 1
+};
+
+enum nsTopLevelWidgetZPlacement {  // for PlaceBehind()
+  eZPlacementBottom = 0,           // bottom of the window stack
+  eZPlacementBelow,                // just below another widget
+  eZPlacementTop                   // top of the window stack
+};
+
+/**
+ * Before the OS goes to sleep, this topic is notified.
+ */
+#define NS_WIDGET_SLEEP_OBSERVER_TOPIC "sleep_notification"
+
+/**
+ * After the OS wakes up, this topic is notified.
+ */
+#define NS_WIDGET_WAKE_OBSERVER_TOPIC "wake_notification"
+
+/**
+ * Before the OS suspends the current process, this topic is notified.  Some
+ * OS will kill processes that are suspended instead of resuming them.
+ * For that reason this topic may be useful to safely close down resources.
+ */
+#define NS_WIDGET_SUSPEND_PROCESS_OBSERVER_TOPIC "suspend_process_notification"
+
+/**
+ * After the current process resumes from being suspended, this topic is
+ * notified.
+ */
+#define NS_WIDGET_RESUME_PROCESS_OBSERVER_TOPIC "resume_process_notification"
+
+/**
+ * When an app(-shell) is activated by the OS, this topic is notified.
+ * Currently, this only happens on Mac OSX.
+ */
+#define NS_WIDGET_MAC_APP_ACTIVATE_OBSERVER_TOPIC "mac_app_activate"
+
+namespace mozilla::widget {
+
+/**
+ * Size constraints for setting the minimum and maximum size of a widget.
+ * Values are in device pixels.
+ */
+struct SizeConstraints {
+  SizeConstraints()
+      : mMaxSize(MOZ_WIDGET_MAX_SIZE, MOZ_WIDGET_MAX_SIZE),
+        mScale(MOZ_WIDGET_INVALID_SCALE) {}
+
+  SizeConstraints(mozilla::LayoutDeviceIntSize aMinSize,
+                  mozilla::LayoutDeviceIntSize aMaxSize,
+                  mozilla::DesktopToLayoutDeviceScale aScale)
+      : mMinSize(aMinSize), mMaxSize(aMaxSize), mScale(aScale) {
+    if (mMaxSize.width > MOZ_WIDGET_MAX_SIZE) {
+      mMaxSize.width = MOZ_WIDGET_MAX_SIZE;
+    }
+    if (mMaxSize.height > MOZ_WIDGET_MAX_SIZE) {
+      mMaxSize.height = MOZ_WIDGET_MAX_SIZE;
+    }
+  }
+
+  mozilla::LayoutDeviceIntSize mMinSize;
+  mozilla::LayoutDeviceIntSize mMaxSize;
+
+  /*
+   * The scale used to convert from desktop to device dimensions.
+   * MOZ_WIDGET_INVALID_SCALE if the value is not known.
+   *
+   * Bug 1701109 is filed to revisit adding of 'mScale' and deal
+   * with multi-monitor scaling issues in more complete way across
+   * all widget implementations.
+   */
+  mozilla::DesktopToLayoutDeviceScale mScale;
+};
+
+struct AutoObserverNotifier {
+  AutoObserverNotifier(nsIObserver* aObserver, const char* aTopic)
+      : mObserver(aObserver), mTopic(aTopic) {}
+
+  void SkipNotification() { mObserver = nullptr; }
+
+  uint64_t SaveObserver() {
+    if (!mObserver) {
+      return 0;
+    }
+    uint64_t observerId = ++sObserverId;
+    sSavedObservers.InsertOrUpdate(observerId, mObserver);
+    SkipNotification();
+    return observerId;
+  }
+
+  ~AutoObserverNotifier() {
+    if (mObserver) {
+      mObserver->Observe(nullptr, mTopic, nullptr);
+    }
+  }
+
+  static void NotifySavedObserver(const uint64_t& aObserverId,
+                                  const char* aTopic) {
+    nsCOMPtr<nsIObserver> observer = sSavedObservers.Get(aObserverId);
+    if (!observer) {
+      MOZ_ASSERT(aObserverId == 0,
+                 "We should always find a saved observer for nonzero IDs");
+      return;
+    }
+
+    sSavedObservers.Remove(aObserverId);
+    observer->Observe(nullptr, aTopic, nullptr);
+  }
+
+ private:
+  nsCOMPtr<nsIObserver> mObserver;
+  const char* mTopic;
+
+ private:
+  static uint64_t sObserverId;
+  static nsTHashMap<uint64_t, nsCOMPtr<nsIObserver>> sSavedObservers;
+};
+
+}  // namespace mozilla::widget
+
+/**
+ * The base class for all the widgets. It provides the interface for
+ * all basic and necessary functionality.
+ */
+class nsIWidget : public nsISupports {
+ protected:
+  typedef mozilla::dom::BrowserChild BrowserChild;
+
+ public:
+  typedef mozilla::layers::CompositorBridgeChild CompositorBridgeChild;
+  typedef mozilla::layers::AsyncDragMetrics AsyncDragMetrics;
+  typedef mozilla::layers::FrameMetrics FrameMetrics;
+  typedef mozilla::layers::LayerManager LayerManager;
+  typedef mozilla::WindowRenderer WindowRenderer;
+  typedef mozilla::layers::LayersBackend LayersBackend;
+  typedef mozilla::layers::LayersId LayersId;
+  typedef mozilla::layers::ScrollableLayerGuid ScrollableLayerGuid;
+  typedef mozilla::layers::ZoomConstraints ZoomConstraints;
+  typedef mozilla::widget::IMEEnabled IMEEnabled;
+  typedef mozilla::widget::IMEMessage IMEMessage;
+  typedef mozilla::widget::IMENotification IMENotification;
+  typedef mozilla::widget::IMENotificationRequests IMENotificationRequests;
+  typedef mozilla::widget::IMEState IMEState;
+  typedef mozilla::widget::InputContext InputContext;
+  typedef mozilla::widget::InputContextAction InputContextAction;
+  typedef mozilla::widget::NativeIMEContext NativeIMEContext;
+  typedef mozilla::widget::SizeConstraints SizeConstraints;
+  typedef mozilla::widget::TextEventDispatcher TextEventDispatcher;
+  typedef mozilla::widget::TextEventDispatcherListener
+      TextEventDispatcherListener;
+  typedef mozilla::LayoutDeviceIntMargin LayoutDeviceIntMargin;
+  typedef mozilla::LayoutDeviceIntPoint LayoutDeviceIntPoint;
+  typedef mozilla::LayoutDeviceIntRect LayoutDeviceIntRect;
+  typedef mozilla::LayoutDeviceIntRegion LayoutDeviceIntRegion;
+  typedef mozilla::LayoutDeviceIntSize LayoutDeviceIntSize;
+  typedef mozilla::ScreenIntPoint ScreenIntPoint;
+  typedef mozilla::ScreenIntMargin ScreenIntMargin;
+  typedef mozilla::ScreenIntSize ScreenIntSize;
+  typedef mozilla::ScreenPoint ScreenPoint;
+  typedef mozilla::CSSToScreenScale CSSToScreenScale;
+  typedef mozilla::DesktopIntRect DesktopIntRect;
+  typedef mozilla::DesktopPoint DesktopPoint;
+  typedef mozilla::DesktopIntPoint DesktopIntPoint;
+  typedef mozilla::DesktopRect DesktopRect;
+  typedef mozilla::DesktopSize DesktopSize;
+  typedef mozilla::CSSPoint CSSPoint;
+  typedef mozilla::CSSRect CSSRect;
+
+  using InitData = mozilla::widget::InitData;
+  using WindowType = mozilla::widget::WindowType;
+  using PopupType = mozilla::widget::PopupType;
+  using PopupLevel = mozilla::widget::PopupLevel;
+  using BorderStyle = mozilla::widget::BorderStyle;
+  using TransparencyMode = mozilla::widget::TransparencyMode;
+  using Screen = mozilla::widget::Screen;
+
+  // Used in UpdateThemeGeometries.
+  struct ThemeGeometry {
+    // The ThemeGeometryType value for the themed widget, see
+    // nsITheme::ThemeGeometryTypeForWidget.
+    nsITheme::ThemeGeometryType mType;
+    // The device-pixel rect within the window for the themed widget
+    LayoutDeviceIntRect mRect;
+
+    ThemeGeometry(nsITheme::ThemeGeometryType aType,
+                  const LayoutDeviceIntRect& aRect)
+        : mType(aType), mRect(aRect) {}
+  };
+
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_IWIDGET_IID)
+
+  nsIWidget()
+      : mLastChild(nullptr),
+        mPrevSibling(nullptr),
+        mOnDestroyCalled(false),
+        mWindowType(WindowType::Child),
+        mZIndex(0)
+
+  {
+    ClearNativeTouchSequence(nullptr);
+  }
+
+  /**
+   * Create and initialize a widget.
+   *
+   * All the arguments can be null in which case a top level window
+   * with size 0 is created. The event callback function has to be
+   * provided only if the caller wants to deal with the events this
+   * widget receives.  The event callback is basically a preprocess
+   * hook called synchronously. The return value determines whether
+   * the event goes to the default window procedure or it is hidden
+   * to the os. The assumption is that if the event handler returns
+   * false the widget does not see the event. The widget should not
+   * automatically clear the window to the background color. The
+   * calling code must handle paint messages and clear the background
+   * itself.
+   *
+   * In practice at least one of aParent and aNativeParent will be null. If
+   * both are null the widget isn't parented (e.g. context menus or
+   * independent top level windows).
+   *
+   * The dimensions given in aRect are specified in the parent's
+   * device coordinate system.
+   * This must not be called for parentless widgets such as top-level
+   * windows, which use the desktop pixel coordinate system; a separate
+   * method is provided for these.
+   *
+   * @param     aParent       parent nsIWidget
+   * @param     aNativeParent native parent widget
+   * @param     aRect         the widget dimension
+   * @param     aInitData     data that is used for widget initialization
+   *
+   */
+  [[nodiscard]] virtual nsresult Create(nsIWidget* aParent,
+                                        nsNativeWidget aNativeParent,
+                                        const LayoutDeviceIntRect& aRect,
+                                        InitData* = nullptr) = 0;
+
+  /*
+   * As above, but with aRect specified in DesktopPixel units (for top-level
+   * widgets).
+   * Default implementation just converts aRect to device pixels and calls
+   * through to device-pixel Create, but platforms may override this if the
+   * mapping is not straightforward or the native platform needs to use the
+   * desktop pixel values directly.
+   */
+  [[nodiscard]] virtual nsresult Create(nsIWidget* aParent,
+                                        nsNativeWidget aNativeParent,
+                                        const DesktopIntRect& aRect,
+                                        InitData* aInitData = nullptr) {
+    LayoutDeviceIntRect devPixRect =
+        RoundedToInt(aRect * GetDesktopToDeviceScale());
+    return Create(aParent, aNativeParent, devPixRect, aInitData);
+  }
+
+  /**
+   * Allocate, initialize, and return a widget that is a child of
+   * |this|.  The returned widget (if nonnull) has gone through the
+   * equivalent of CreateInstance(widgetCID) + Create(...).
+   *
+   * |CreateChild()| lets widget backends decide whether to parent
+   * the new child widget to this, nonnatively parent it, or both.
+   * This interface exists to support the PuppetWidget backend,
+   * which is entirely non-native.  All other params are the same as
+   * for |Create()|.
+   *
+   * |aForceUseIWidgetParent| forces |CreateChild()| to only use the
+   * |nsIWidget*| this, not its native widget (if it exists), when
+   * calling |Create()|.  This is a timid hack around poorly
+   * understood code, and shouldn't be used in new code.
+   */
+  virtual already_AddRefed<nsIWidget> CreateChild(
+      const LayoutDeviceIntRect& aRect, InitData* = nullptr,
+      bool aForceUseIWidgetParent = false) = 0;
+
+  /**
+   * Attach to a top level widget.
+   *
+   * In cases where a top level chrome widget is being used as a content
+   * container, attach a secondary listener and update the device
+   * context. The primary widget listener will continue to be called for
+   * notifications relating to the top-level window, whereas other
+   * notifications such as painting and events will instead be called via
+   * the attached listener. SetAttachedWidgetListener should be used to
+   * assign the attached listener.
+   *
+   * aUseAttachedEvents if true, events are sent to the attached listener
+   * instead of the normal listener.
+   */
+  virtual void AttachViewToTopLevel(bool aUseAttachedEvents) = 0;
+
+  /**
+   * Accessor functions to get and set the attached listener. Used by
+   * nsView in connection with AttachViewToTopLevel above.
+   */
+  virtual void SetAttachedWidgetListener(nsIWidgetListener* aListener) = 0;
+  virtual nsIWidgetListener* GetAttachedWidgetListener() const = 0;
+  virtual void SetPreviouslyAttachedWidgetListener(
+      nsIWidgetListener* aListener) = 0;
+  virtual nsIWidgetListener* GetPreviouslyAttachedWidgetListener() = 0;
+
+  /**
+   * Notifies the root widget of a non-blank paint.
+   */
+  virtual void DidGetNonBlankPaint() {}
+
+  /**
+   * Accessor functions to get and set the listener which handles various
+   * actions for the widget.
+   */
+  //@{
+  virtual nsIWidgetListener* GetWidgetListener() const = 0;
+  virtual void SetWidgetListener(nsIWidgetListener* alistener) = 0;
+  //@}
+
+  /**
+   * Close and destroy the internal native window.
+   * This method does not delete the widget.
+   */
+
+  virtual void Destroy() = 0;
+
+  /**
+   * Destroyed() returns true if Destroy() has been called already.
+   * Otherwise, false.
+   */
+  bool Destroyed() const { return mOnDestroyCalled; }
+
+  /**
+   * Reparent a widget
+   *
+   * Change the widget's parent. Null parents are allowed.
+   *
+   * @param     aNewParent   new parent
+   */
+  virtual void SetParent(nsIWidget* aNewParent) = 0;
+
+  /**
+   * Return the parent Widget of this Widget or nullptr if this is a
+   * top level window
+   *
+   * @return the parent widget or nullptr if it does not have a parent
+   *
+   */
+  virtual nsIWidget* GetParent(void) = 0;
+
+  /**
+   * Return the top level Widget of this Widget
+   *
+   * @return the top level widget
+   */
+  virtual nsIWidget* GetTopLevelWidget() = 0;
+
+  /**
+   * Return the top (non-sheet) parent of this Widget if it's a sheet,
+   * or nullptr if this isn't a sheet (or some other error occurred).
+   * Sheets are only supported on some platforms (currently only macOS).
+   *
+   * @return the top (non-sheet) parent widget or nullptr
+   *
+   */
+  virtual nsIWidget* GetSheetWindowParent(void) = 0;
+
+  /**
+   * Return the physical DPI of the screen containing the window ...
+   * the number of device pixels per inch.
+   */
+  virtual float GetDPI() = 0;
+
+  /**
+   * Fallback DPI for when there's no widget available.
+   */
+  static float GetFallbackDPI();
+
+  /**
+   * Return the scaling factor between device pixels and the platform-
+   * dependent "desktop pixels" used to manage window positions on a
+   * potentially multi-screen, mixed-resolution desktop.
+   */
+  virtual mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale() = 0;
+
+  /**
+   * Return the scaling factor between device pixels and the platform-
+   * dependent "desktop pixels" by looking up the screen by the position
+   * of the widget.
+   */
+  virtual mozilla::DesktopToLayoutDeviceScale
+  GetDesktopToDeviceScaleByScreen() = 0;
+
+  /**
+   * Return the default scale factor for the window. This is the
+   * default number of device pixels per CSS pixel to use. This should
+   * depend on OS/platform settings such as the Mac's "UI scale factor"
+   * or Windows' "font DPI". This will take into account Gecko preferences
+   * overriding the system setting.
+   */
+  mozilla::CSSToLayoutDeviceScale GetDefaultScale();
+
+  /**
+   * Fallback default scale for when there's no widget available.
+   */
+  static mozilla::CSSToLayoutDeviceScale GetFallbackDefaultScale();
+
+  /**
+   * Return the first child of this widget.  Will return null if
+   * there are no children.
+   */
+  nsIWidget* GetFirstChild() const { return mFirstChild; }
+
+  /**
+   * Return the last child of this widget.  Will return null if
+   * there are no children.
+   */
+  nsIWidget* GetLastChild() const { return mLastChild; }
+
+  /**
+   * Return the next sibling of this widget
+   */
+  nsIWidget* GetNextSibling() const { return mNextSibling; }
+
+  /**
+   * Set the next sibling of this widget
+   */
+  void SetNextSibling(nsIWidget* aSibling) { mNextSibling = aSibling; }
+
+  /**
+   * Return the previous sibling of this widget
+   */
+  nsIWidget* GetPrevSibling() const { return mPrevSibling; }
+
+  /**
+   * Set the previous sibling of this widget
+   */
+  void SetPrevSibling(nsIWidget* aSibling) { mPrevSibling = aSibling; }
+
+  /**
+   * Show or hide this widget
+   *
+   * @param aState true to show the Widget, false to hide it
+   *
+   */
+  virtual void Show(bool aState) = 0;
+
+  /**
+   * Whether or not a widget must be recreated after being hidden to show
+   * again properly.
+   */
+  virtual bool NeedsRecreateToReshow() { return false; }
+
+  /**
+   * Make the window modal.
+   */
+  virtual void SetModal(bool aModal) = 0;
+
+  /**
+   * Make the non-modal window opened by modal window fake-modal, that will
+   * call SetFakeModal(false) on destroy on Cocoa.
+   */
+  virtual void SetFakeModal(bool aModal) { SetModal(aModal); }
+
+  /**
+   * Are we app modal. Currently only implemented on Cocoa.
+   */
+  virtual bool IsRunningAppModal() { return false; }
+
+  /**
+   * The maximum number of simultaneous touch contacts supported by the device.
+   * In the case of devices with multiple digitizers (e.g. multiple touch
+   * screens), the value will be the maximum of the set of maximum supported
+   * contacts by each individual digitizer.
+   */
+  virtual uint32_t GetMaxTouchPoints() const = 0;
+
+  /**
+   * Returns whether the window is visible
+   *
+   */
+  virtual bool IsVisible() const = 0;
+
+  /**
+   * Returns whether the window has allocated resources so
+   * we can paint into it.
+   * Recently it's used on Linux/Gtk where we should not paint
+   * to invisible window.
+   */
+  virtual bool IsMapped() const { return true; }
+
+  /**
+   * Perform platform-dependent sanity check on a potential window position.
+   * This is guaranteed to work only for top-level windows.
+   */
+  virtual void ConstrainPosition(DesktopIntPoint&) = 0;
+
+  /**
+   * NOTE:
+   *
+   * For a top-level window widget, the "parent's coordinate system" is the
+   * "global" display pixel coordinate space, *not* device pixels (which
+   * may be inconsistent between multiple screens, at least in the Mac OS
+   * case with mixed hi-dpi and lo-dpi displays). This applies to all the
+   * following Move and Resize widget APIs.
+   *
+   * The display-/device-pixel distinction becomes important for (at least)
+   * macOS with Hi-DPI (retina) displays, and Windows when the UI scale factor
+   * is set to other than 100%.
+   *
+   * The Move and Resize methods take floating-point parameters, rather than
+   * integer ones. This is important when manipulating top-level widgets,
+   * where the coordinate system may not be an integral multiple of the
+   * device-pixel space.
+   **/
+
+  /**
+   * Move this widget.
+   *
+   * Coordinates refer to the top-left of the widget.  For toplevel windows
+   * with decorations, this is the top-left of the titlebar and frame .
+   *
+   * @param aX the new x position expressed in the parent's coordinate system
+   * @param aY the new y position expressed in the parent's coordinate system
+   *
+   **/
+  virtual void Move(double aX, double aY) = 0;
+
+  /**
+   * Reposition this widget so that the client area has the given offset.
+   *
+   * @param aOffset  the new offset of the client area expressed as an
+   *                 offset from the origin of the client area of the parent
+   *                 widget (for root widgets and popup widgets it is in
+   *                 screen coordinates)
+   **/
+  virtual void MoveClient(const DesktopPoint& aOffset) = 0;
+
+  /**
+   * Resize this widget. Any size constraints set for the window by a
+   * previous call to SetSizeConstraints will be applied.
+   *
+   * @param aWidth  the new width expressed in the parent's coordinate system
+   * @param aHeight the new height expressed in the parent's coordinate
+   *                system
+   * @param aRepaint whether the widget should be repainted
+   */
+  virtual void Resize(double aWidth, double aHeight, bool aRepaint) = 0;
+
+  /**
+   * Lock the aspect ratio of a Window
+   *
+   * @param aShouldLock bool
+   *
+   */
+  virtual void LockAspectRatio(bool aShouldLock){};
+
+  /**
+   * Move or resize this widget. Any size constraints set for the window by
+   * a previous call to SetSizeConstraints will be applied.
+   *
+   * @param aX       the new x position expressed in the parent's coordinate
+   *                 system
+   * @param aY       the new y position expressed in the parent's coordinate
+   *                 system
+   * @param aWidth   the new width expressed in the parent's coordinate system
+   * @param aHeight  the new height expressed in the parent's coordinate
+   *                 system
+   * @param aRepaint whether the widget should be repainted if the size
+   *                 changes
+   *
+   */
+  virtual void Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) = 0;
+
+  virtual mozilla::Maybe<bool> IsResizingNativeWidget() {
+    return mozilla::Nothing();
+  }
+
+  /**
+   * Resize the widget so that the inner client area has the given size.
+   *
+   * @param aSize    the new size of the client area.
+   * @param aRepaint whether the widget should be repainted
+   */
+  virtual void ResizeClient(const DesktopSize& aSize, bool aRepaint) = 0;
+
+  /**
+   * Resize and reposition the widget so tht inner client area has the given
+   * offset and size.
+   *
+   * @param aRect    the new offset and size of the client area. The offset is
+   *                 expressed as an offset from the origin of the client area
+   *                 of the parent widget (for root widgets and popup widgets it
+   *                 is in screen coordinates).
+   * @param aRepaint whether the widget should be repainted
+   */
+  virtual void ResizeClient(const DesktopRect& aRect, bool aRepaint) = 0;
+
+  /**
+   * Sets the widget's z-index.
+   */
+  virtual void SetZIndex(int32_t aZIndex) = 0;
+
+  /**
+   * Gets the widget's z-index.
+   */
+  int32_t GetZIndex() { return mZIndex; }
+
+  /**
+   * Position this widget just behind the given widget. (Used to
+   * control z-order for top-level widgets. Get/SetZIndex by contrast
+   * control z-order for child widgets of other widgets.)
+   * @param aPlacement top, bottom, or below a widget
+   *                   (if top or bottom, param aWidget is ignored)
+   * @param aWidget    widget to place this widget behind
+   *                   (only if aPlacement is eZPlacementBelow).
+   *                   null is equivalent to aPlacement of eZPlacementTop
+   * @param aActivate  true to activate the widget after placing it
+   */
+  virtual void PlaceBehind(nsTopLevelWidgetZPlacement aPlacement,
+                           nsIWidget* aWidget, bool aActivate) = 0;
+
+  /**
+   * Minimize, maximize or normalize the window size.
+   * Takes a value from nsSizeMode (see nsIWidgetListener.h)
+   */
+  virtual void SetSizeMode(nsSizeMode aMode) = 0;
+
+  virtual void GetWorkspaceID(nsAString& workspaceID) = 0;
+
+  virtual void MoveToWorkspace(const nsAString& workspaceID) = 0;
+
+  /**
+   * Suppress animations that are applied to a window by OS.
+   */
+  virtual void SuppressAnimation(bool aSuppress) {}
+
+  /**
+   * Return size mode (minimized, maximized, normalized).
+   * Returns a value from nsSizeMode (see nsIWidgetListener.h)
+   */
+  virtual nsSizeMode SizeMode() = 0;
+
+  /**
+   * Ask whether the window is tiled.
+   */
+  virtual bool IsTiled() const = 0;
+
+  /**
+   * Ask wether the widget is fully occluded
+   */
+  virtual bool IsFullyOccluded() const = 0;
+
+  /**
+   * Enable or disable this Widget
+   *
+   * @param aState true to enable the Widget, false to disable it.
+   */
+  virtual void Enable(bool aState) = 0;
+
+  /**
+   * Ask whether the widget is enabled
+   */
+  virtual bool IsEnabled() const = 0;
+
+  /*
+   * Whether we should request activation of this widget's toplevel window.
+   */
+  enum class Raise {
+    No,
+    Yes,
+  };
+
+  /**
+   * Request activation of this window or give focus to this widget.
+   */
+  virtual void SetFocus(Raise, mozilla::dom::CallerType aCallerType) = 0;
+
+  /**
+   * Get this widget's outside dimensions relative to its parent widget. For
+   * popup widgets the returned rect is in screen coordinates and not
+   * relative to its parent widget.
+   *
+   * @return the x, y, width and height of this widget.
+   */
+  virtual LayoutDeviceIntRect GetBounds() = 0;
+
+  /**
+   * Get this widget's outside dimensions in device coordinates. This
+   * includes any title bar on the window.
+   *
+   * @return the x, y, width and height of this widget.
+   */
+  virtual LayoutDeviceIntRect GetScreenBounds() = 0;
+
+  /**
+   * Similar to GetScreenBounds except that this function will always
+   * get the size when the widget is in the nsSizeMode_Normal size mode
+   * even if the current size mode is not nsSizeMode_Normal.
+   * This method will fail if the size mode is not nsSizeMode_Normal and
+   * the platform doesn't have the ability.
+   * This method will always succeed if the current size mode is
+   * nsSizeMode_Normal.
+   *
+   * @param aRect   On return it holds the  x, y, width and height of
+   *                this widget.
+   */
+  [[nodiscard]] virtual nsresult GetRestoredBounds(
+      LayoutDeviceIntRect& aRect) = 0;
+
+  /**
+   * Get this widget's client area bounds, if the window has a 3D border
+   * appearance this returns the area inside the border. The position is the
+   * position of the client area relative to the client area of the parent
+   * widget (for root widgets and popup widgets it is in screen coordinates).
+   *
+   * @return the x, y, width and height of the client area of this widget.
+   */
+  virtual LayoutDeviceIntRect GetClientBounds() = 0;
+
+  /**
+   * Sets the non-client area dimensions of the window. Pass -1 to restore
+   * the system default frame size for that border. Pass zero to remove
+   * a border, or pass a specific value adjust a border. Units are in
+   * pixels. (DPI dependent)
+   *
+   * Platform notes:
+   *  Windows: shrinking top non-client height will remove application
+   *  icon and window title text. Glass desktops will refuse to set
+   *  dimensions between zero and size < system default.
+   */
+  virtual nsresult SetNonClientMargins(const LayoutDeviceIntMargin&) = 0;
+
+  /**
+   * Sets the region around the edges of the window that can be dragged to
+   * resize the window. All four sides of the window will get the same margin.
+   */
+  virtual void SetResizeMargin(mozilla::LayoutDeviceIntCoord aResizeMargin) = 0;
+  /**
+   * Get the client offset from the window origin.
+   *
+   * @return the x and y of the offset.
+   */
+  virtual LayoutDeviceIntPoint GetClientOffset() = 0;
+
+  /**
+   * Returns the slop from the screen edges in device pixels.
+   * @see Window.screenEdgeSlop{X,Y}
+   */
+  virtual LayoutDeviceIntPoint GetScreenEdgeSlop() { return {}; }
+
+  /**
+   * Equivalent to GetClientBounds but only returns the size.
+   */
+  virtual LayoutDeviceIntSize GetClientSize() {
+    // Depending on the backend, overloading this method may be useful if
+    // requesting the client offset is expensive.
+    return GetClientBounds().Size();
+  }
+
+  /**
+   * Set the background color for this widget
+   *
+   * @param aColor the new background color
+   *
+   */
+
+  virtual void SetBackgroundColor(const nscolor& aColor) {}
+
+  /**
+   * If a cursor type is currently cached locally for this widget, clear the
+   * cached cursor to force an update on the next SetCursor call.
+   */
+
+  virtual void ClearCachedCursor() = 0;
+
+  struct Cursor {
+    // The system cursor chosen by the page. This is used if there's no custom
+    // cursor, or if we fail to use the custom cursor in some way (if the image
+    // fails to load, for example).
+    nsCursor mDefaultCursor = eCursor_standard;
+    // May be null, to represent no custom cursor image.
+    nsCOMPtr<imgIContainer> mContainer;
+    uint32_t mHotspotX = 0;
+    uint32_t mHotspotY = 0;
+    mozilla::ImageResolution mResolution;
+
+    bool IsCustom() const { return !!mContainer; }
+
+    bool operator==(const Cursor& aOther) const {
+      return mDefaultCursor == aOther.mDefaultCursor &&
+             mContainer.get() == aOther.mContainer.get() &&
+             mHotspotX == aOther.mHotspotX && mHotspotY == aOther.mHotspotY &&
+             mResolution == aOther.mResolution;
+    }
+
+    bool operator!=(const Cursor& aOther) const { return !(*this == aOther); }
+  };
+
+  /**
+   * Sets the cursor for this widget.
+   */
+  virtual void SetCursor(const Cursor&) = 0;
+
+  virtual void SetCustomCursorAllowed(bool) = 0;
+
+  static nsIntSize CustomCursorSize(const Cursor&);
+
+  /**
+   * Get the window type of this widget.
+   */
+  WindowType GetWindowType() const { return mWindowType; }
+
+  /**
+   * Set the transparency mode of the top-level window containing this widget.
+   * So, e.g., if you call this on the widget for an IFRAME, the top level
+   * browser window containing the IFRAME actually gets set. Be careful.
+   *
+   * This can fail if the platform doesn't support
+   * transparency/glass. By default widgets are not
+   * transparent.  This will also fail if the toplevel window is not
+   * a Mozilla window, e.g., if the widget is in an embedded
+   * context.
+   *
+   * After transparency/glass has been enabled, the initial alpha channel
+   * value for all pixels is 1, i.e., opaque.
+   * If the window is resized then the alpha channel values for
+   * all pixels are reset to 1.
+   * Pixel RGB color values are already premultiplied with alpha channel values.
+   */
+  virtual void SetTransparencyMode(TransparencyMode aMode) = 0;
+
+  /**
+   * Get the transparency mode of the top-level window that contains this
+   * widget.
+   */
+  virtual TransparencyMode GetTransparencyMode() = 0;
+
+  /**
+   * Set the shadow style of the window.
+   *
+   * Ignored on child widgets and on non-Mac platforms.
+   */
+  virtual void SetWindowShadowStyle(mozilla::WindowShadow aStyle) = 0;
+
+  /**
+   * Set the opacity of the window.
+   * Values need to be between 0.0f (invisible) and 1.0f (fully opaque).
+   *
+   * Ignored on child widgets and on non-Mac platforms.
+   */
+  virtual void SetWindowOpacity(float aOpacity) {}
+
+  /**
+   * Set the transform of the window. Values are in device pixels,
+   * the origin is the top left corner of the window.
+   *
+   * Ignored on child widgets and on non-Mac platforms.
+   */
+  virtual void SetWindowTransform(const mozilla::gfx::Matrix& aTransform) {}
+
+  /**
+   * Set the preferred color-scheme for the widget.
+   * Ignored on non-Mac platforms.
+   */
+  virtual void SetColorScheme(const mozilla::Maybe<mozilla::ColorScheme>&) {}
+
+  /**
+   * Set whether the window should ignore mouse events or not, and if it should
+   * not, what input margin should it use.
+   *
+   * This is only used on popup windows. The margin is only implemented on
+   * Linux.
+   */
+  struct InputRegion {
+    bool mFullyTransparent = false;
+    mozilla::LayoutDeviceIntCoord mMargin = 0;
+  };
+  virtual void SetInputRegion(const InputRegion&) {}
+
+  /*
+   * On macOS, this method shows or hides the pill button in the titlebar
+   * that's used to collapse the toolbar.
+   *
+   * Ignored on child widgets and on non-Mac platforms.
+   */
+  virtual void SetShowsToolbarButton(bool aShow) = 0;
+
+  /*
+   * On macOS, this method determines whether we tell cocoa that the window
+   * supports native full screen. If we do so, and another window is in
+   * native full screen, this window will also appear in native full screen.
+   *
+   * We generally only want to do this for primary application windows.
+   *
+   * Ignored on child widgets and on non-Mac platforms.
+   */
+  virtual void SetSupportsNativeFullscreen(bool aSupportsNativeFullscreen) = 0;
+
+  enum WindowAnimationType {
+    eGenericWindowAnimation,
+    eDocumentWindowAnimation
+  };
+
+  /**
+   * Sets the kind of top-level window animation this widget should have. On
+   * macOS, this causes a particular kind of animation to be shown when the
+   * window is first made visible.
+   *
+   * Ignored on child widgets and on non-Mac platforms.
+   */
+  virtual void SetWindowAnimationType(WindowAnimationType aType) = 0;
+
+  /**
+   * Specifies whether the window title should be drawn even if the window
+   * contents extend into the titlebar. Ignored on windows that don't draw
+   * in the titlebar. Only implemented on macOS.
+   */
+  virtual void SetDrawsTitle(bool aDrawTitle) {}
+
+  /**
+   * Hide window chrome (borders, buttons) for this widget.
+   *
+   */
+  virtual void HideWindowChrome(bool aShouldHide) = 0;
+
+  enum FullscreenTransitionStage {
+    eBeforeFullscreenToggle,
+    eAfterFullscreenToggle
+  };
+
+  /**
+   * Prepares for fullscreen transition and returns whether the widget
+   * supports fullscreen transition. If this method returns false,
+   * PerformFullscreenTransition() must never be called. Otherwise,
+   * caller should call that method twice with "before" and "after"
+   * stages respectively in order. In the latter case, this method may
+   * return some data via aData pointer. Caller must pass that data to
+   * PerformFullscreenTransition() if any, and caller is responsible
+   * for releasing that data.
+   */
+  virtual bool PrepareForFullscreenTransition(nsISupports** aData) = 0;
+
+  /**
+   * Performs fullscreen transition. This method returns immediately,
+   * and will post aCallback to the main thread when the transition
+   * finishes.
+   */
+  virtual void PerformFullscreenTransition(FullscreenTransitionStage aStage,
+                                           uint16_t aDuration,
+                                           nsISupports* aData,
+                                           nsIRunnable* aCallback) = 0;
+
+  /**
+   * Perform any actions needed after the fullscreen transition has ended.
+   */
+  virtual void CleanupFullscreenTransition() = 0;
+
+  /**
+   * Return the screen the widget is in, or null if we don't know.
+   */
+  virtual already_AddRefed<Screen> GetWidgetScreen() = 0;
+
+  /**
+   * Put the toplevel window into or out of fullscreen mode.
+   *
+   * @return NS_OK if the widget is setup properly for fullscreen and
+   * FullscreenChanged callback has been or will be called. If other
+   * value is returned, the caller should continue the change itself.
+   */
+  virtual nsresult MakeFullScreen(bool aFullScreen) = 0;
+
+  /**
+   * Same as MakeFullScreen, except that, on systems which natively
+   * support fullscreen transition, calling this method explicitly
+   * requests that behavior.
+   * It is currently only supported on macOS 10.7+.
+   */
+  virtual nsresult MakeFullScreenWithNativeTransition(bool aFullScreen) {
+    return MakeFullScreen(aFullScreen);
+  }
+
+  /**
+   * Invalidate a specified rect for a widget so that it will be repainted
+   * later.
+   */
+  virtual void Invalidate(const LayoutDeviceIntRect& aRect) = 0;
+
+  enum LayerManagerPersistence {
+    LAYER_MANAGER_CURRENT = 0,
+    LAYER_MANAGER_PERSISTENT
+  };
+
+  /**
+   * Return the widget's LayerManager. The layer tree for that LayerManager is
+   * what gets rendered to the widget.
+   *
+   * Note that this tries to create a renderer if it doesn't exist.
+   */
+  virtual WindowRenderer* GetWindowRenderer() = 0;
+
+  /**
+   * Returns whether there's an existing window renderer.
+   */
+  virtual bool HasWindowRenderer() const = 0;
+
+  /**
+   * Called before each layer manager transaction to allow any preparation
+   * for DrawWindowUnderlay/Overlay that needs to be on the main thread.
+   *
+   * Always called on the main thread.
+   */
+  virtual void PrepareWindowEffects() = 0;
+
+  /**
+   * Called when Gecko knows which themed widgets exist in this window.
+   * The passed array contains an entry for every themed widget of the right
+   * type (currently only StyleAppearance::Toolbar) within the window, except
+   * for themed widgets which are transformed or have effects applied to them
+   * (e.g. CSS opacity or filters).
+   * This could sometimes be called during display list construction
+   * outside of painting.
+   * If called during painting, it will be called before we actually
+   * paint anything.
+   */
+  virtual void UpdateThemeGeometries(
+      const nsTArray<ThemeGeometry>& aThemeGeometries) = 0;
+
+  /**
+   * Informs the widget about the region of the window that is opaque.
+   *
+   * @param aOpaqueRegion the region of the window that is opaque.
+   */
+  virtual void UpdateOpaqueRegion(const LayoutDeviceIntRegion& aOpaqueRegion) {}
+
+  /**
+   * Informs the widget about the region of the window that is draggable.
+   */
+  virtual void UpdateWindowDraggingRegion(
+      const LayoutDeviceIntRegion& aRegion) {}
+
+  /**
+   * Tells the widget whether the given input block results in a swipe.
+   * Should be called in response to a WidgetWheelEvent that has
+   * mFlags.mCanTriggerSwipe set on it.
+   */
+  virtual void ReportSwipeStarted(uint64_t aInputBlockId, bool aStartSwipe) {}
+
+  /**
+   * Internal methods
+   */
+
+  //@{
+  virtual void AddChild(nsIWidget* aChild) = 0;
+  virtual void RemoveChild(nsIWidget* aChild) = 0;
+  virtual void* GetNativeData(uint32_t aDataType) = 0;
+  virtual void FreeNativeData(void* data, uint32_t aDataType) = 0;  //~~~
+
+  //@}
+
+  /**
+   * Set the widget's title.
+   * Must be called after Create.
+   *
+   * @param aTitle string displayed as the title of the widget
+   */
+  virtual nsresult SetTitle(const nsAString& aTitle) = 0;
+
+  /**
+   * Set the widget's icon.
+   * Must be called after Create.
+   *
+   * @param aIconSpec string specifying the icon to use; convention is to
+   *                  pass a resource: URL from which a platform-dependent
+   *                  resource file name will be constructed
+   */
+  virtual void SetIcon(const nsAString& aIconSpec) = 0;
+
+  /**
+   * Return this widget's origin in screen coordinates.
+   *
+   * @return screen coordinates stored in the x,y members
+   */
+  virtual LayoutDeviceIntPoint WidgetToScreenOffset() = 0;
+
+  /**
+   * The same as WidgetToScreenOffset(), except in the case of
+   * PuppetWidget where this method omits the chrome offset.
+   */
+  virtual LayoutDeviceIntPoint TopLevelWidgetToScreenOffset() {
+    return WidgetToScreenOffset();
+  }
+
+  /**
+   * For a PuppetWidget, returns the transform from the coordinate
+   * space of the PuppetWidget to the coordinate space of the
+   * top-level native widget.
+   *
+   * Identity transform in other cases.
+   */
+  virtual mozilla::LayoutDeviceToLayoutDeviceMatrix4x4
+  WidgetToTopLevelWidgetTransform() {
+    return mozilla::LayoutDeviceToLayoutDeviceMatrix4x4();
+  }
+
+  mozilla::LayoutDeviceIntPoint WidgetToTopLevelWidgetOffset() {
+    return mozilla::LayoutDeviceIntPoint::Round(
+        WidgetToTopLevelWidgetTransform().TransformPoint(
+            mozilla::LayoutDevicePoint()));
+  }
+
+  /**
+   * Returns the margins that are applied to go from client sizes to window
+   * sizes (which includes window borders and titlebar).
+   * This method should work even when the window is not yet visible.
+   */
+  virtual LayoutDeviceIntMargin ClientToWindowMargin() { return {}; }
+
+  LayoutDeviceIntSize ClientToWindowSizeDifference();
+
+  /**
+   * Dispatches an event to the widget
+   */
+  virtual nsresult DispatchEvent(mozilla::WidgetGUIEvent* event,
+                                 nsEventStatus& aStatus) = 0;
+
+  /**
+   * Dispatches an event to APZ only.
+   * No-op in the child process.
+   */
+  virtual void DispatchEventToAPZOnly(mozilla::WidgetInputEvent* aEvent) = 0;
+
+  /*
+   * Dispatch a gecko event for this widget.
+   * Returns true if it's consumed.  Otherwise, false.
+   */
+  virtual bool DispatchWindowEvent(mozilla::WidgetGUIEvent& event) = 0;
+
+  // A structure that groups the statuses from APZ dispatch and content
+  // dispatch.
+  struct ContentAndAPZEventStatus {
+    // Either of these may not be set if the event was not dispatched
+    // to APZ or to content.
+    nsEventStatus mApzStatus = nsEventStatus_eIgnore;
+    nsEventStatus mContentStatus = nsEventStatus_eIgnore;
+  };
+
+  /**
+   * Dispatches an event that must be handled by APZ first, when APZ is
+   * enabled. If invoked in the child process, it is forwarded to the
+   * parent process synchronously.
+   */
+  virtual ContentAndAPZEventStatus DispatchInputEvent(
+      mozilla::WidgetInputEvent* aEvent) = 0;
+
+  /**
+   * Confirm an APZ-aware event target. This should be used when APZ will
+   * not need a layers update to process the event.
+   */
+  virtual void SetConfirmedTargetAPZC(
+      uint64_t aInputBlockId,
+      const nsTArray<ScrollableLayerGuid>& aTargets) const = 0;
+
+  /**
+   * Returns true if APZ is in use, false otherwise.
+   */
+  virtual bool AsyncPanZoomEnabled() const = 0;
+
+  /**
+   */
+  virtual void SwipeFinished() = 0;
+
+  /**
+   * Enables the dropping of files to a widget.
+   */
+  virtual void EnableDragDrop(bool aEnable) = 0;
+  virtual nsresult AsyncEnableDragDrop(bool aEnable) = 0;
+
+  /**
+   * Classify the window for the window manager. Mostly for X11.
+   *
+   *  @param xulWinType The window type. Characters other than [A-Za-z0-9_-] are
+   *                    converted to '_'. Anything before the first colon is
+   *                    assigned to name, anything after it to role. If there's
+   *                    no colon, assign the whole thing to both role and name.
+   *
+   * @param xulWinClass The window class. If set, overrides the normal value.
+   *                    Otherwise, the program class it used.
+   *
+   * @param xulWinName The window name. If set, overrides the value specified in
+   *                   window type. Otherwise, name from window type is used.
+   *
+   */
+  virtual void SetWindowClass(const nsAString& xulWinType,
+                              const nsAString& xulWinClass,
+                              const nsAString& xulWinName) = 0;
+
+  /**
+   * Enables/Disables system capture of any and all events that would cause a
+   * popup to be rolled up. aListener should be set to a non-null value for
+   * any popups that are not managed by the popup manager.
+   * @param aDoCapture true enables capture, false disables capture
+   *
+   */
+  virtual void CaptureRollupEvents(bool aDoCapture) = 0;
+
+  /**
+   * Bring this window to the user's attention.  This is intended to be a more
+   * gentle notification than popping the window to the top or putting up an
+   * alert.  See, for example, Win32 FlashWindow or the NotificationManager on
+   * the Mac.  The notification should be suppressed if the window is already
+   * in the foreground and should be dismissed when the user brings this window
+   * to the foreground.
+   * @param aCycleCount Maximum number of times to animate the window per system
+   *                    conventions. If set to -1, cycles indefinitely until
+   *                    window is brought into the foreground.
+   */
+  [[nodiscard]] virtual nsresult GetAttention(int32_t aCycleCount) = 0;
+
+  /**
+   * Ask whether there user input events pending.  All input events are
+   * included, including those not targeted at this nsIwidget instance.
+   */
+  virtual bool HasPendingInputEvent() = 0;
+
+  /*
+   * Determine whether the widget shows a resize widget. If it does,
+   * aResizerRect returns the resizer's rect.
+   *
+   * Returns false on any platform that does not support it.
+   *
+   * @param aResizerRect The resizer's rect in device pixels.
+   * @return Whether a resize widget is shown.
+   */
+  virtual bool ShowsResizeIndicator(LayoutDeviceIntRect* aResizerRect) = 0;
+
+  // TODO: Make this an enum class with MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS or
+  //       EnumSet class.
+  enum Modifiers : uint32_t {
+    NO_MODIFIERS = 0x00000000,
+    CAPS_LOCK = 0x00000001,  // when CapsLock is active
+    NUM_LOCK = 0x00000002,   // when NumLock is active
+    SHIFT_L = 0x00000100,
+    SHIFT_R = 0x00000200,
+    CTRL_L = 0x00000400,
+    CTRL_R = 0x00000800,
+    ALT_L = 0x00001000,  // includes Option
+    ALT_R = 0x00002000,
+    COMMAND_L = 0x00004000,
+    COMMAND_R = 0x00008000,
+    HELP = 0x00010000,
+    ALTGRAPH = 0x00020000,  // AltGr key on Windows.  This emulates
+                            // AltRight key behavior of keyboard
+                            // layouts which maps AltGr to AltRight
+                            // key.
+    FUNCTION = 0x00100000,
+    NUMERIC_KEY_PAD = 0x01000000  // when the key is coming from the keypad
+  };
+  /**
+   * Utility method intended for testing. Dispatches native key events
+   * to this widget to simulate the press and release of a key.
+   * @param aNativeKeyboardLayout a *platform-specific* constant.
+   * On Mac, this is the resource ID for a 'uchr' or 'kchr' resource.
+   * On Windows, it is converted to a hex string and passed to
+   * LoadKeyboardLayout, see
+   * http://msdn.microsoft.com/en-us/library/ms646305(VS.85).aspx
+   * @param aNativeKeyCode a *platform-specific* keycode.
+   * On Windows, this is the virtual key code.
+   * @param aModifiers some combination of the above 'Modifiers' flags;
+   * not all flags will apply to all platforms. Mac ignores the _R
+   * modifiers. Windows ignores COMMAND, NUMERIC_KEY_PAD, HELP and
+   * FUNCTION.
+   * @param aCharacters characters that the OS would decide to generate
+   * from the event. On Windows, this is the charCode passed by
+   * WM_CHAR.
+   * @param aUnmodifiedCharacters characters that the OS would decide
+   * to generate from the event if modifier keys (other than shift)
+   * were assumed inactive. Needed on Mac, ignored on Windows.
+   * @param aObserver the observer that will get notified once the events
+   * have been dispatched.
+   * @return NS_ERROR_NOT_AVAILABLE to indicate that the keyboard
+   * layout is not supported and the event was not fired
+   */
+  virtual nsresult SynthesizeNativeKeyEvent(
+      int32_t aNativeKeyboardLayout, int32_t aNativeKeyCode,
+      uint32_t aModifierFlags, const nsAString& aCharacters,
+      const nsAString& aUnmodifiedCharacters, nsIObserver* aObserver) = 0;
+
+  /**
+   * Utility method intended for testing. Dispatches native mouse events
+   * may even move the mouse cursor. On Mac the events are guaranteed to
+   * be sent to the window containing this widget, but on Windows they'll go
+   * to whatever's topmost on the screen at that position, so for
+   * cross-platform testing ensure that your window is at the top of the
+   * z-order.
+   * @param aPoint screen location of the mouse, in device
+   * pixels, with origin at the top left
+   * @param aNativeMessage abstract native message.
+   * @param aButton Mouse button defined by DOM UI Events.
+   * @param aModifierFlags Some values of nsIWidget::Modifiers.
+   *                       FYI: On Windows, Android and Headless widget on all
+   *                       platroms, this hasn't been handled yet.
+   * @param aObserver the observer that will get notified once the events
+   * have been dispatched.
+   */
+  enum class NativeMouseMessage : uint32_t {
+    ButtonDown,   // button down
+    ButtonUp,     // button up
+    Move,         // mouse cursor move
+    EnterWindow,  // mouse cursor comes into a window
+    LeaveWindow,  // mouse cursor leaves from a window
+  };
+  virtual nsresult SynthesizeNativeMouseEvent(
+      LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+      mozilla::MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+      nsIObserver* aObserver) = 0;
+
+  /**
+   * A shortcut to SynthesizeNativeMouseEvent, abstracting away the native
+   * message. aPoint is location in device pixels to which the mouse pointer
+   * moves to.
+   * @param aObserver the observer that will get notified once the events
+   * have been dispatched.
+   */
+  virtual nsresult SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
+                                             nsIObserver* aObserver) = 0;
+
+  /**
+   * Utility method intended for testing. Dispatching native mouse scroll
+   * events may move the mouse cursor.
+   *
+   * @param aPoint            Mouse cursor position in screen coordinates.
+   *                          In device pixels, the origin at the top left of
+   *                          the primary display.
+   * @param aNativeMessage    Platform native message.
+   * @param aDeltaX           The delta value for X direction.  If the native
+   *                          message doesn't indicate X direction scrolling,
+   *                          this may be ignored.
+   * @param aDeltaY           The delta value for Y direction.  If the native
+   *                          message doesn't indicate Y direction scrolling,
+   *                          this may be ignored.
+   * @param aDeltaZ           The delta value for Z direction.  If the native
+   *                          message doesn't indicate Z direction scrolling,
+   *                          this may be ignored.
+   * @param aModifierFlags    Must be values of Modifiers, or zero.
+   * @param aAdditionalFlags  See nsIDOMWidnowUtils' consts and their
+   *                          document.
+   * @param aObserver         The observer that will get notified once the
+   *                          events have been dispatched.
+   */
+  virtual nsresult SynthesizeNativeMouseScrollEvent(
+      LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage, double aDeltaX,
+      double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+      uint32_t aAdditionalFlags, nsIObserver* aObserver) = 0;
+
+  /*
+   * TouchPointerState states for SynthesizeNativeTouchPoint. Match
+   * touch states in nsIDOMWindowUtils.idl.
+   */
+  enum TouchPointerState {
+    // The pointer is in a hover state above the digitizer
+    TOUCH_HOVER = (1 << 0),
+    // The pointer is in contact with the digitizer
+    TOUCH_CONTACT = (1 << 1),
+    // The pointer has been removed from the digitizer detection area
+    TOUCH_REMOVE = (1 << 2),
+    // The pointer has been canceled. Will cancel any pending os level
+    // gestures that would triggered as a result of completion of the
+    // input sequence. This may not cancel moz platform related events
+    // that might get tirggered by input already delivered.
+    TOUCH_CANCEL = (1 << 3),
+
+    // ALL_BITS used for validity checking during IPC serialization
+    ALL_BITS = (1 << 4) - 1
+  };
+  /*
+   * TouchpadGesturePhase states for SynthesizeNativeTouchPadPinch and
+   * SynthesizeNativeTouchpadPan. Match phase states in nsIDOMWindowUtils.idl.
+   */
+  enum TouchpadGesturePhase {
+    PHASE_BEGIN = 0,
+    PHASE_UPDATE = 1,
+    PHASE_END = 2
+  };
+  /*
+   * Create a new or update an existing touch pointer on the digitizer.
+   * To trigger os level gestures, individual touch points should
+   * transition through a complete set of touch states which should be
+   * sent as individual messages.
+   *
+   * @param aPointerId The touch point id to create or update.
+   * @param aPointerState one or more of the touch states listed above
+   * @param aPoint coords of this event
+   * @param aPressure 0.0 -> 1.0 float val indicating pressure
+   * @param aOrientation 0 -> 359 degree value indicating the
+   * orientation of the pointer. Use 90 for normal taps.
+   * @param aObserver The observer that will get notified once the events
+   * have been dispatched.
+   */
+  virtual nsresult SynthesizeNativeTouchPoint(uint32_t aPointerId,
+                                              TouchPointerState aPointerState,
+                                              LayoutDeviceIntPoint aPoint,
+                                              double aPointerPressure,
+                                              uint32_t aPointerOrientation,
+                                              nsIObserver* aObserver) = 0;
+  /*
+   * See nsIDOMWindowUtils.sendNativeTouchpadPinch().
+   */
+  virtual nsresult SynthesizeNativeTouchPadPinch(
+      TouchpadGesturePhase aEventPhase, float aScale,
+      LayoutDeviceIntPoint aPoint, int32_t aModifierFlags) = 0;
+
+  /*
+   * Helper for simulating a simple tap event with one touch point. When
+   * aLongTap is true, simulates a native long tap with a duration equal to
+   * ui.click_hold_context_menus.delay. This pref is compatible with the
+   * apzc long tap duration. Defaults to 1.5 seconds.
+   * @param aObserver The observer that will get notified once the events
+   * have been dispatched.
+   */
+  virtual nsresult SynthesizeNativeTouchTap(LayoutDeviceIntPoint aPoint,
+                                            bool aLongTap,
+                                            nsIObserver* aObserver);
+
+  virtual nsresult SynthesizeNativePenInput(uint32_t aPointerId,
+                                            TouchPointerState aPointerState,
+                                            LayoutDeviceIntPoint aPoint,
+                                            double aPressure,
+                                            uint32_t aRotation, int32_t aTiltX,
+                                            int32_t aTiltY, int32_t aButton,
+                                            nsIObserver* aObserver) = 0;
+
+  /*
+   * Cancels all active simulated touch input points and pending long taps.
+   * Native widgets should track existing points such that they can clear the
+   * digitizer state when this call is made.
+   * @param aObserver The observer that will get notified once the touch
+   * sequence has been cleared.
+   */
+  virtual nsresult ClearNativeTouchSequence(nsIObserver* aObserver);
+
+  /*
+   * Send a native event as if the user double tapped the touchpad with two
+   * fingers.
+   */
+  virtual nsresult SynthesizeNativeTouchpadDoubleTap(
+      LayoutDeviceIntPoint aPoint, uint32_t aModifierFlags) = 0;
+
+  /*
+   * See nsIDOMWindowUtils.sendNativeTouchpadPan().
+   */
+  virtual nsresult SynthesizeNativeTouchpadPan(TouchpadGesturePhase aEventPhase,
+                                               LayoutDeviceIntPoint aPoint,
+                                               double aDeltaX, double aDeltaY,
+                                               int32_t aModifierFlags,
+                                               nsIObserver* aObserver) = 0;
+
+  virtual void StartAsyncScrollbarDrag(
+      const AsyncDragMetrics& aDragMetrics) = 0;
+
+  /**
+   * Notify APZ to start autoscrolling.
+   * @param aAnchorLocation the location of the autoscroll anchor
+   * @param aGuid identifies the scroll frame to be autoscrolled
+   * @return true if APZ has been successfully notified
+   */
+  virtual bool StartAsyncAutoscroll(const ScreenPoint& aAnchorLocation,
+                                    const ScrollableLayerGuid& aGuid) = 0;
+
+  /**
+   * Notify APZ to stop autoscrolling.
+   * @param aGuid identifies the scroll frame which is being autoscrolled.
+   */
+  virtual void StopAsyncAutoscroll(const ScrollableLayerGuid& aGuid) = 0;
+
+  virtual LayersId GetRootLayerTreeId() = 0;
+
+  // If this widget supports out-of-process compositing, it can override
+  // this method to provide additional information to the compositor.
+  virtual void GetCompositorWidgetInitData(
+      mozilla::widget::CompositorWidgetInitData* aInitData) {}
+
+  /**
+   * Setter/Getter of the system font setting for testing.
+   */
+  virtual nsresult SetSystemFont(const nsCString& aFontName) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+  virtual nsresult GetSystemFont(nsCString& aFontName) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  /**
+   * Wayland specific routines.
+   */
+  virtual LayoutDeviceIntSize GetMoveToRectPopupSize() const {
+    NS_WARNING("GetLayoutPopupRect implemented only for wayland");
+    return LayoutDeviceIntSize();
+  }
+
+  /**
+   * If this widget uses native pointer lock instead of warp-to-center
+   * (currently only GTK on Wayland), these methods provide access to that
+   * functionality.
+   */
+  virtual void SetNativePointerLockCenter(
+      const LayoutDeviceIntPoint& aLockCenter) {}
+  virtual void LockNativePointer() {}
+  virtual void UnlockNativePointer() {}
+
+  /*
+   * Get safe area insets except to cutout.
+   * See https://drafts.csswg.org/css-env-1/#safe-area-insets.
+   */
+  virtual mozilla::ScreenIntMargin GetSafeAreaInsets() const {
+    return mozilla::ScreenIntMargin();
+  }
+
+ private:
+  class LongTapInfo {
+   public:
+    LongTapInfo(int32_t aPointerId, LayoutDeviceIntPoint& aPoint,
+                mozilla::TimeDuration aDuration, nsIObserver* aObserver)
+        : mPointerId(aPointerId),
+          mPosition(aPoint),
+          mDuration(aDuration),
+          mObserver(aObserver),
+          mStamp(mozilla::TimeStamp::Now()) {}
+
+    int32_t mPointerId;
+    LayoutDeviceIntPoint mPosition;
+    mozilla::TimeDuration mDuration;
+    nsCOMPtr<nsIObserver> mObserver;
+    mozilla::TimeStamp mStamp;
+  };
+
+  static void OnLongTapTimerCallback(nsITimer* aTimer, void* aClosure);
+
+  static already_AddRefed<nsIBidiKeyboard> CreateBidiKeyboardContentProcess();
+  static already_AddRefed<nsIBidiKeyboard> CreateBidiKeyboardInner();
+
+  mozilla::UniquePtr<LongTapInfo> mLongTapTouchPoint;
+  nsCOMPtr<nsITimer> mLongTapTimer;
+  static int32_t sPointerIdCounter;
+
+ public:
+  /**
+   * If key events have not been handled by content or XBL handlers, they can
+   * be offered to the system (for custom application shortcuts set in system
+   * preferences, for example).
+   */
+  virtual void PostHandleKeyEvent(mozilla::WidgetKeyboardEvent* aEvent);
+
+  /**
+   * Activates a native menu item at the position specified by the index
+   * string. The index string is a string of positive integers separated
+   * by the "|" (pipe) character. The last integer in the string represents
+   * the item index in a submenu located using the integers preceding it.
+   *
+   * Example: 1|0|4
+   * In this string, the first integer represents the top-level submenu
+   * in the native menu bar. Since the integer is 1, it is the second submeu
+   * in the native menu bar. Within that, the first item (index 0) is a
+   * submenu, and we want to activate the 5th item within that submenu.
+   */
+  virtual nsresult ActivateNativeMenuItemAt(const nsAString& indexString) = 0;
+
+  /**
+   * This is used for native menu system testing.
+   *
+   * Updates a native menu at the position specified by the index string.
+   * The index string is a string of positive integers separated by the "|"
+   * (pipe) character.
+   *
+   * Example: 1|0|4
+   * In this string, the first integer represents the top-level submenu
+   * in the native menu bar. Since the integer is 1, it is the second submeu
+   * in the native menu bar. Within that, the first item (index 0) is a
+   * submenu, and we want to update submenu at index 4 within that submenu.
+   *
+   * If this is called with an empty string it forces a full reload of the
+   * menu system.
+   */
+  virtual nsresult ForceUpdateNativeMenuAt(const nsAString& indexString) = 0;
+
+  /**
+   * This is used for testing macOS service menu code.
+   *
+   * @param aResult - the current text selection. Is empty if no selection.
+   * @return nsresult - whether or not aResult was assigned the selected text.
+   */
+  [[nodiscard]] virtual nsresult GetSelectionAsPlaintext(nsAString& aResult) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  /**
+   * Notify IME of the specified notification.
+   *
+   * @return If the notification is mouse button event and it's consumed by
+   *         IME, this returns NS_SUCCESS_EVENT_CONSUMED.
+   */
+  virtual nsresult NotifyIME(const IMENotification& aIMENotification) = 0;
+
+  /**
+   * MaybeDispatchInitialFocusEvent will dispatch a focus event after creation
+   * of the widget, in the event that we were not able to observe and respond to
+   * the initial focus event. This is necessary for the early skeleton UI
+   * window, which is displayed and receives its initial focus event before we
+   * can actually respond to it.
+   */
+  virtual void MaybeDispatchInitialFocusEvent() {}
+
+  /*
+   * Notifies the input context changes.
+   */
+  virtual void SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction) = 0;
+
+  /*
+   * Get current input context.
+   */
+  virtual InputContext GetInputContext() = 0;
+
+  /**
+   * Get native IME context.  This is different from GetNativeData() with
+   * NS_RAW_NATIVE_IME_CONTEXT, the result is unique even if in a remote
+   * process.
+   */
+  virtual NativeIMEContext GetNativeIMEContext() = 0;
+
+  /*
+   * Given a WidgetKeyboardEvent, this method synthesizes a corresponding
+   * native (OS-level) event for it. This method allows tests to simulate
+   * keystrokes that trigger native key bindings (which require a native
+   * event).
+   */
+  [[nodiscard]] virtual nsresult AttachNativeKeyEvent(
+      mozilla::WidgetKeyboardEvent& aEvent) = 0;
+
+  /**
+   * Retrieve edit commands when the key combination of aEvent is used
+   * in platform native applications.
+   */
+  MOZ_CAN_RUN_SCRIPT virtual bool GetEditCommands(
+      mozilla::NativeKeyBindingsType aType,
+      const mozilla::WidgetKeyboardEvent& aEvent,
+      nsTArray<mozilla::CommandInt>& aCommands);
+
+  /*
+   * Retrieves a reference to notification requests of IME.  Note that the
+   * reference is valid while the nsIWidget instance is alive.  So, if you
+   * need to store the reference for a long time, you need to grab the widget
+   * instance too.
+   */
+  const IMENotificationRequests& IMENotificationRequestsRef();
+
+  /*
+   * Call this method when a dialog is opened which has a default button.
+   * The button's rectangle should be supplied in aButtonRect.
+   */
+  [[nodiscard]] virtual nsresult OnDefaultButtonLoaded(
+      const LayoutDeviceIntRect& aButtonRect) = 0;
+
+  /**
+   * Return true if this process shouldn't use platform widgets, and
+   * so should use PuppetWidgets instead.  If this returns true, the
+   * result of creating and using a platform widget is undefined,
+   * and likely to end in crashes or other buggy behavior.
+   */
+  static bool UsePuppetWidgets() { return XRE_IsContentProcess(); }
+
+  static already_AddRefed<nsIWidget> CreateTopLevelWindow();
+
+  static already_AddRefed<nsIWidget> CreateChildWindow();
+
+  /**
+   * Allocate and return a "puppet widget" that doesn't directly
+   * correlate to a platform widget; platform events and data must
+   * be fed to it.  Currently used in content processes.  NULL is
+   * returned if puppet widgets aren't supported in this build
+   * config, on this platform, or for this process type.
+   *
+   * This function is called "Create" to match CreateInstance().
+   * The returned widget must still be nsIWidget::Create()d.
+   */
+  static already_AddRefed<nsIWidget> CreatePuppetWidget(
+      BrowserChild* aBrowserChild);
+
+  static already_AddRefed<nsIWidget> CreateHeadlessWidget();
+
+  /**
+   * Reparent this widget's native widget.
+   * @param aNewParent the native widget of aNewParent is the new native
+   *                   parent widget
+   */
+  virtual void ReparentNativeWidget(nsIWidget* aNewParent) = 0;
+
+  /**
+   * Return true if widget has it's own GL context
+   */
+  virtual bool HasGLContext() { return false; }
+
+  /**
+   * Returns true to indicate that this widget paints an opaque background
+   * that we want to be visible under the page, so layout should not force
+   * a default background.
+   */
+  virtual bool WidgetPaintsBackground() { return false; }
+
+  virtual bool NeedsPaint() { return IsVisible() && !GetBounds().IsEmpty(); }
+
+  /**
+   * Get the natural bounds of this widget.  This method is only
+   * meaningful for widgets for which Gecko implements screen
+   * rotation natively.  When this is the case, GetBounds() returns
+   * the widget bounds taking rotation into account, and
+   * GetNaturalBounds() returns the bounds *not* taking rotation
+   * into account.
+   *
+   * No code outside of the composition pipeline should know or care
+   * about this.  If you're not an agent of the compositor, you
+   * probably shouldn't call this method.
+   */
+  virtual LayoutDeviceIntRect GetNaturalBounds() { return GetBounds(); }
+
+  /**
+   * Set size constraints on the window size such that it is never less than
+   * the specified minimum size and never larger than the specified maximum
+   * size. The size constraints are sizes of the outer rectangle including
+   * the window frame and title bar. Use 0 for an unconstrained minimum size
+   * and NS_MAXSIZE for an unconstrained maximum size. Note that this method
+   * does not necessarily change the size of a window to conform to this size,
+   * thus Resize should be called afterwards.
+   *
+   * @param aConstraints: the size constraints in device pixels
+   */
+  virtual void SetSizeConstraints(const SizeConstraints& aConstraints) = 0;
+
+  /**
+   * Return the size constraints currently observed by the widget.
+   *
+   * @return the constraints in device pixels
+   */
+  virtual const SizeConstraints GetSizeConstraints() = 0;
+
+  /**
+   * Apply the current size constraints to the given size.
+   *
+   * @param aWidth width to constrain
+   * @param aHeight height to constrain
+   */
+  virtual void ConstrainSize(int32_t* aWidth, int32_t* aHeight) = 0;
+
+  /**
+   * If this is owned by a BrowserChild, return that.  Otherwise return
+   * null.
+   */
+  virtual BrowserChild* GetOwningBrowserChild() { return nullptr; }
+
+  /**
+   * If this isn't directly compositing to its window surface,
+   * return the compositor which is doing that on our behalf.
+   */
+  virtual CompositorBridgeChild* GetRemoteRenderer() { return nullptr; }
+
+  /**
+   * If there is a remote renderer, pause or resume it.
+   */
+  virtual void PauseOrResumeCompositor(bool aPause);
+
+  /**
+   * Clear WebRender resources
+   */
+  virtual void ClearCachedWebrenderResources() {}
+
+  /**
+   * Clear WebRender animation resources
+   */
+  virtual void ClearWebrenderAnimationResources() {}
+
+  /**
+   * Request fast snapshot at RenderCompositor of WebRender.
+   * Since readback of Windows DirectComposition is very slow.
+   */
+  virtual bool SetNeedFastSnaphot() { return false; }
+
+  /**
+   * If this widget has its own vsync dispatcher, return it, otherwise return
+   * nullptr. An example of such a local vsync dispatcher would be Wayland frame
+   * callbacks.
+   */
+  virtual RefPtr<mozilla::VsyncDispatcher> GetVsyncDispatcher();
+
+  /**
+   * Returns true if the widget requires synchronous repaints on resize,
+   * false otherwise.
+   */
+  virtual bool SynchronouslyRepaintOnResize() { return true; }
+
+  /**
+   * Some platforms (only cocoa right now) round widget coordinates to the
+   * nearest even pixels (see bug 892994), this function allows us to
+   * determine how widget coordinates will be rounded.
+   */
+  virtual int32_t RoundsWidgetCoordinatesTo() { return 1; }
+
+  virtual void UpdateZoomConstraints(
+      const uint32_t& aPresShellId, const ScrollableLayerGuid::ViewID& aViewId,
+      const mozilla::Maybe<ZoomConstraints>& aConstraints){};
+
+  /**
+   * GetTextEventDispatcher() returns TextEventDispatcher belonging to the
+   * widget.  Note that this never returns nullptr.
+   */
+  virtual TextEventDispatcher* GetTextEventDispatcher() = 0;
+
+  /**
+   * GetNativeTextEventDispatcherListener() returns a
+   * TextEventDispatcherListener instance which is used when the widget
+   * instance handles native IME and/or keyboard events.
+   */
+  virtual TextEventDispatcherListener*
+  GetNativeTextEventDispatcherListener() = 0;
+
+  /**
+   * Trigger an animation to zoom to the given |aRect|.
+   * |aRect| should be relative to the layout viewport of the widget's root
+   * document
+   */
+  virtual void ZoomToRect(const uint32_t& aPresShellId,
+                          const ScrollableLayerGuid::ViewID& aViewId,
+                          const CSSRect& aRect, const uint32_t& aFlags) = 0;
+
+  /**
+   * LookUpDictionary shows the dictionary for the word around current point.
+   *
+   * @param aText            the word to look up dictiorary.
+   * @param aFontRangeArray  text decoration of aText
+   * @param aIsVertical      true if the word is vertical layout
+   * @param aPoint           top-left point of aText
+   */
+  virtual void LookUpDictionary(
+      const nsAString& aText,
+      const nsTArray<mozilla::FontRange>& aFontRangeArray,
+      const bool aIsVertical, const LayoutDeviceIntPoint& aPoint) {}
+
+  virtual void RequestFxrOutput() {
+    MOZ_ASSERT(false, "This function should only execute in Windows");
+  }
+
+#if defined(MOZ_WIDGET_ANDROID)
+  /**
+   * RecvToolbarAnimatorMessageFromCompositor receive message from compositor
+   * thread.
+   *
+   * @param aMessage message being sent to Android UI thread.
+   */
+  virtual void RecvToolbarAnimatorMessageFromCompositor(int32_t aMessage) = 0;
+
+  /**
+   * UpdateRootFrameMetrics steady state frame metrics send from compositor
+   * thread
+   *
+   * @param aScrollOffset  page scroll offset value in screen pixels.
+   * @param aZoom          current page zoom.
+   */
+  virtual void UpdateRootFrameMetrics(const ScreenPoint& aScrollOffset,
+                                      const CSSToScreenScale& aZoom) = 0;
+
+  /**
+   * RecvScreenPixels Buffer containing the pixel from the frame buffer. Used
+   * for android robocop tests.
+   *
+   * @param aMem  shared memory containing the frame buffer pixels.
+   * @param aSize size of the buffer in screen pixels.
+   */
+  virtual void RecvScreenPixels(mozilla::ipc::Shmem&& aMem,
+                                const ScreenIntSize& aSize,
+                                bool aNeedsYFlip) = 0;
+
+  virtual void UpdateDynamicToolbarMaxHeight(mozilla::ScreenIntCoord aHeight) {}
+  virtual mozilla::ScreenIntCoord GetDynamicToolbarMaxHeight() const {
+    return 0;
+  }
+#endif
+
+  static already_AddRefed<nsIBidiKeyboard> CreateBidiKeyboard();
+
+  /**
+   * Like GetDefaultScale, but taking into account only the system settings
+   * and ignoring Gecko preferences.
+   */
+  virtual double GetDefaultScaleInternal() { return 1.0; }
+
+  using WindowButtonType = mozilla::WindowButtonType;
+
+  /**
+   * Layout uses this to alert the widget to the client rect representing
+   * the window maximize button.  An empty rect indicates there is no
+   * maximize button (for example, in fullscreen).  This is only implemented
+   * on Windows.
+   */
+  virtual void SetWindowButtonRect(WindowButtonType aButtonType,
+                                   const LayoutDeviceIntRect& aClientRect) {}
+
+#ifdef DEBUG
+  virtual nsresult SetHiDPIMode(bool aHiDPI) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+  virtual nsresult RestoreHiDPIMode() { return NS_ERROR_NOT_IMPLEMENTED; }
+#endif
+
+ protected:
+  // keep the list of children.  We also keep track of our siblings.
+  // The ownership model is as follows: parent holds a strong ref to
+  // the first element of the list, and each element holds a strong
+  // ref to the next element in the list.  The prevsibling and
+  // lastchild pointers are weak, which is fine as long as they are
+  // maintained properly.
+  nsCOMPtr<nsIWidget> mFirstChild;
+  nsIWidget* MOZ_NON_OWNING_REF mLastChild;
+  nsCOMPtr<nsIWidget> mNextSibling;
+  nsIWidget* MOZ_NON_OWNING_REF mPrevSibling;
+  // When Destroy() is called, the sub class should set this true.
+  bool mOnDestroyCalled;
+  WindowType mWindowType;
+  int32_t mZIndex;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsIWidget, NS_IWIDGET_IID)
+
+#endif  // nsIWidget_h__
diff --git a/widget/nsIWidgetListener.cpp b/widget/nsIWidgetListener.cpp
new file mode 100644
index 0000000000..b9f236f159
--- /dev/null
+++ b/widget/nsIWidgetListener.cpp
@@ -0,0 +1,89 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIWidgetListener.h"
+
+#include "nsRegion.h"
+#include "nsView.h"
+#include "nsIWidget.h"
+#include "nsIAppWindow.h"
+
+#include "mozilla/BasicEvents.h"
+#include "mozilla/PresShell.h"
+
+using namespace mozilla;
+
+nsIAppWindow* nsIWidgetListener::GetAppWindow() { return nullptr; }
+
+nsView* nsIWidgetListener::GetView() { return nullptr; }
+
+PresShell* nsIWidgetListener::GetPresShell() { return nullptr; }
+
+bool nsIWidgetListener::WindowMoved(nsIWidget* aWidget, int32_t aX, int32_t aY,
+                                    ByMoveToRect) {
+  return false;
+}
+
+bool nsIWidgetListener::WindowResized(nsIWidget* aWidget, int32_t aWidth,
+                                      int32_t aHeight) {
+  return false;
+}
+
+void nsIWidgetListener::SizeModeChanged(nsSizeMode aSizeMode) {}
+
+void nsIWidgetListener::SafeAreaInsetsChanged(const mozilla::ScreenIntMargin&) {
+}
+
+void nsIWidgetListener::UIResolutionChanged() {}
+
+#if defined(MOZ_WIDGET_ANDROID)
+void nsIWidgetListener::DynamicToolbarMaxHeightChanged(ScreenIntCoord aHeight) {
+}
+void nsIWidgetListener::DynamicToolbarOffsetChanged(ScreenIntCoord aOffset) {}
+#endif
+
+void nsIWidgetListener::MacFullscreenMenubarOverlapChanged(
+    mozilla::DesktopCoord aOverlapAmount) {}
+
+bool nsIWidgetListener::ZLevelChanged(bool aImmediate, nsWindowZ* aPlacement,
+                                      nsIWidget* aRequestBelow,
+                                      nsIWidget** aActualBelow) {
+  return false;
+}
+
+void nsIWidgetListener::OcclusionStateChanged(bool aIsFullyOccluded) {}
+
+void nsIWidgetListener::WindowActivated() {}
+
+void nsIWidgetListener::WindowDeactivated() {}
+
+void nsIWidgetListener::OSToolbarButtonPressed() {}
+
+bool nsIWidgetListener::RequestWindowClose(nsIWidget* aWidget) { return false; }
+
+void nsIWidgetListener::WillPaintWindow(nsIWidget* aWidget) {}
+
+bool nsIWidgetListener::PaintWindow(nsIWidget* aWidget,
+                                    LayoutDeviceIntRegion aRegion) {
+  return false;
+}
+
+void nsIWidgetListener::DidPaintWindow() {}
+
+void nsIWidgetListener::DidCompositeWindow(
+    mozilla::layers::TransactionId aTransactionId,
+    const TimeStamp& aCompositeStart, const TimeStamp& aCompositeEnd) {}
+
+void nsIWidgetListener::RequestRepaint() {}
+
+bool nsIWidgetListener::ShouldNotBeVisible() {
+  // Returns false to assume that nothing should happen in most cases.
+  return false;
+}
+
+nsEventStatus nsIWidgetListener::HandleEvent(WidgetGUIEvent* aEvent,
+                                             bool aUseAttachedEvents) {
+  return nsEventStatus_eIgnore;
+}
diff --git a/widget/nsIWidgetListener.h b/widget/nsIWidgetListener.h
new file mode 100644
index 0000000000..aff753aaec
--- /dev/null
+++ b/widget/nsIWidgetListener.h
@@ -0,0 +1,194 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsIWidgetListener_h__
+#define nsIWidgetListener_h__
+
+#include <stdint.h>
+
+#include "mozilla/EventForwards.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/TimeStamp.h"
+
+#include "nsRegionFwd.h"
+#include "Units.h"
+
+class nsView;
+class nsIWidget;
+class nsIAppWindow;
+
+namespace mozilla {
+class PresShell;
+}  // namespace mozilla
+
+/**
+ * sizemode is an adjunct to widget size
+ */
+enum nsSizeMode {
+  nsSizeMode_Normal = 0,
+  nsSizeMode_Minimized,
+  nsSizeMode_Maximized,
+  nsSizeMode_Fullscreen,
+  nsSizeMode_Invalid
+};
+
+/**
+ * different types of (top-level) window z-level positioning
+ */
+enum nsWindowZ {
+  nsWindowZTop = 0,  // on top
+  nsWindowZBottom,   // on bottom
+  nsWindowZRelative  // just below some specified widget
+};
+
+class nsIWidgetListener {
+ public:
+  /**
+   * If this listener is for an nsIAppWindow, return it. If this is null, then
+   * this is likely a listener for a view, which can be determined using
+   * GetView. If both methods return null, this will be an nsWebBrowser.
+   */
+  virtual nsIAppWindow* GetAppWindow();
+
+  /**
+   * If this listener is for an nsView, return it.
+   */
+  virtual nsView* GetView();
+
+  /**
+   * Return the presshell for this widget listener.
+   */
+  virtual mozilla::PresShell* GetPresShell();
+
+  /**
+   * Called when a window is moved to location (x, y). Returns true if the
+   * notification was handled. Coordinates are outer window screen coordinates.
+   */
+  enum class ByMoveToRect : bool { No, Yes };
+  virtual bool WindowMoved(nsIWidget* aWidget, int32_t aX, int32_t aY,
+                           ByMoveToRect);
+
+  /**
+   * Called when a window is resized to (width, height). Returns true if the
+   * notification was handled. Coordinates are outer window screen coordinates.
+   */
+  virtual bool WindowResized(nsIWidget* aWidget, int32_t aWidth,
+                             int32_t aHeight);
+
+  /**
+   * Called when the size mode (minimized, maximized, fullscreen) is changed.
+   */
+  virtual void SizeModeChanged(nsSizeMode aSizeMode);
+
+  /**
+   * Called when the DPI (device resolution scaling factor) is changed,
+   * such that UI elements may need to be rescaled.
+   */
+  virtual void UIResolutionChanged();
+
+#if defined(MOZ_WIDGET_ANDROID)
+  virtual void DynamicToolbarMaxHeightChanged(mozilla::ScreenIntCoord aHeight);
+  virtual void DynamicToolbarOffsetChanged(mozilla::ScreenIntCoord aOffset);
+#endif
+
+  /**
+   * Called when the z-order of the window is changed. Returns true if the
+   * notification was handled. aPlacement indicates the new z order. If
+   * placement is nsWindowZRelative, then aRequestBelow should be the
+   * window to place below. On return, aActualBelow will be set to the
+   * window actually behind. This generally only applies to Windows.
+   */
+  virtual bool ZLevelChanged(bool aImmediate, nsWindowZ* aPlacement,
+                             nsIWidget* aRequestBelow,
+                             nsIWidget** aActualBelow);
+
+  /**
+   * Called when the macOS titlebar is shown while in fullscreen.
+   */
+  virtual void MacFullscreenMenubarOverlapChanged(
+      mozilla::DesktopCoord aOverlapAmount);
+
+  /**
+   * Called when the occlusion state is changed.
+   */
+  virtual void OcclusionStateChanged(bool aIsFullyOccluded);
+
+  /**
+   * Called when the window is activated and focused.
+   */
+  virtual void WindowActivated();
+
+  /**
+   * Called when the window is deactivated and no longer focused.
+   */
+  virtual void WindowDeactivated();
+
+  /**
+   * Called when the show/hide toolbar button on the Mac titlebar is pressed.
+   */
+  virtual void OSToolbarButtonPressed();
+
+  /**
+   * Called when a request is made to close the window. Returns true if the
+   * notification was handled. Returns true if the notification was handled.
+   */
+  virtual bool RequestWindowClose(nsIWidget* aWidget);
+
+  /*
+   * Indicate that a paint is about to occur on this window. This is called
+   * at a time when it's OK to change the geometry of this widget or of
+   * other widgets. Must be called before every call to PaintWindow.
+   */
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY
+  virtual void WillPaintWindow(nsIWidget* aWidget);
+
+  /**
+   * Paint the specified region of the window. Returns true if the
+   * notification was handled.
+   * This is called at a time when it is not OK to change the geometry of
+   * this widget or of other widgets.
+   */
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY
+  virtual bool PaintWindow(nsIWidget* aWidget,
+                           mozilla::LayoutDeviceIntRegion aRegion);
+
+  /**
+   * Indicates that a paint occurred.
+   * This is called at a time when it is OK to change the geometry of
+   * this widget or of other widgets.
+   * Must be called after every call to PaintWindow.
+   */
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY
+  virtual void DidPaintWindow();
+
+  virtual void DidCompositeWindow(mozilla::layers::TransactionId aTransactionId,
+                                  const mozilla::TimeStamp& aCompositeStart,
+                                  const mozilla::TimeStamp& aCompositeEnd);
+
+  /**
+   * Request that layout schedules a repaint on the next refresh driver tick.
+   */
+  virtual void RequestRepaint();
+
+  /**
+   * Returns true if this is a popup that should not be visible. If this
+   * is a popup that is visible, not a popup or this state is unknown,
+   * returns false.
+   */
+  virtual bool ShouldNotBeVisible();
+
+  /**
+   * Handle an event.
+   */
+  virtual nsEventStatus HandleEvent(mozilla::WidgetGUIEvent* aEvent,
+                                    bool aUseAttachedEvents);
+
+  /**
+   * Called when safe area insets are changed.
+   */
+  virtual void SafeAreaInsetsChanged(
+      const mozilla::ScreenIntMargin& aSafeAreaInsets);
+};
+
+#endif
diff --git a/widget/nsIWinTaskbar.idl b/widget/nsIWinTaskbar.idl
new file mode 100644
index 0000000000..7d9b96a9d8
--- /dev/null
+++ b/widget/nsIWinTaskbar.idl
@@ -0,0 +1,196 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+#include "nsIBaseWindow.idl"
+
+interface nsIDocShell;
+interface nsIJumpListBuilder;
+interface nsITaskbarTabPreview;
+interface nsITaskbarWindowPreview;
+interface nsITaskbarPreviewController;
+interface nsITaskbarProgress;
+interface nsITaskbarOverlayIconController;
+interface nsILegacyJumpListBuilder;
+interface mozIDOMWindow;
+
+/*
+ * nsIWinTaskbar
+ *
+ * This interface represents a service which exposes the APIs provided by the
+ * Windows taskbar to applications.
+ *
+ * Starting in Windows 7, applications gain some control over their appearance
+ * in the taskbar. By default, there is one taskbar preview per top level
+ * window (excluding popups). This preview is represented by an
+ * nsITaskbarWindowPreview object.
+ *
+ * An application can register its own "tab" previews. Such previews will hide
+ * the corresponding nsITaskbarWindowPreview automatically (though this is not
+ * reflected in the visible attribute of the nsITaskbarWindowPreview). These
+ * tab previews do not have to correspond to tabs in the application - they can
+ * vary in size, shape and location. They do not even need to be actual GUI
+ * elements on the window. Unlike window previews, tab previews require most of
+ * the functionality of the nsITaskbarPreviewController to be implemented.
+ *
+ * Applications can also show progress on their taskbar icon. This does not
+ * interact with the taskbar previews except if the nsITaskbarWindowPreview is
+ * made invisible in which case the progress is naturally not shown on that
+ * window.
+ *
+ * When taskbar icons are combined as is the default in Windows 7, the progress
+ * for those windows is also combined as defined here:
+ * http://msdn.microsoft.com/en-us/library/dd391697%28VS.85%29.aspx
+ *
+ * Applications may also define custom taskbar jump lists on application shortcuts.
+ * See nsILegacyJumpListBuilder for more information.
+ */
+
+[scriptable, uuid(11751471-9246-4c72-a80f-0c7df765d640)]
+interface nsIWinTaskbar : nsISupports
+{
+  /**
+   * Returns true if the operating system supports Win7+ taskbar features.
+   * This property acts as a replacement for in-place os version checking.
+   */
+  readonly attribute boolean available;
+
+  /**
+   * Returns the default application user model identity the application
+   * registers with the system. This id is used by the taskbar in grouping
+   * windows and in associating pinned shortcuts with running instances and
+   * jump lists.
+   */
+  readonly attribute AString defaultGroupId;
+
+  /**
+   * Same as above, but a different value so that Private Browsing windows
+   * can be separated in the Taskbar.
+   */
+  readonly attribute AString defaultPrivateGroupId;
+
+  /**
+   * Taskbar window and tab preview management
+   */
+
+  /**
+   * Creates a taskbar preview. The docshell should be a toplevel docshell and
+   * is used to find the toplevel window. See the documentation for
+   * nsITaskbarTabPreview for more information.
+   */
+  nsITaskbarTabPreview createTaskbarTabPreview(in nsIDocShell shell,
+                                               in nsITaskbarPreviewController controller);
+
+  /**
+   * Gets the taskbar preview for a window. The docshell is used to find the
+   * toplevel window. See the documentation for nsITaskbarTabPreview for more
+   * information.
+   *
+   * Note: to implement custom drawing or buttons, a controller is required.
+   */
+  nsITaskbarWindowPreview getTaskbarWindowPreview(in nsIDocShell shell);
+
+  /**
+   * Taskbar icon progress indicator
+   */
+
+  /**
+   * Gets the taskbar progress for a window. The docshell is used to find the
+   * toplevel window. See the documentation for nsITaskbarProgress for more
+   * information.
+   */
+  nsITaskbarProgress getTaskbarProgress(in nsIDocShell shell);
+
+  /**
+   * Taskbar icon overlay
+   */
+
+  /**
+   * Gets the taskbar icon overlay controller for a window. The docshell is used
+   * to find the toplevel window. See the documentation in
+   * nsITaskbarOverlayIconController for more details.
+   */
+  nsITaskbarOverlayIconController getOverlayIconController(in nsIDocShell shell);
+
+  /**
+   * Taskbar and start menu jump list management
+   */
+
+  /**
+   * Retrieve a legacy taskbar jump list builder. This jump list builder backend
+   * is in the process of being phased out.
+   *
+   * Fails if a jump list build operation has already been initiated, developers
+   * should make use of a single instance of nsILegacyJumpListBuilder for building lists
+   * within an application.
+   *
+   * @throws NS_ERROR_ALREADY_INITIALIZED if an nsILegacyJumpListBuilder instance is
+   * currently building a list.
+   */
+  nsILegacyJumpListBuilder createLegacyJumpListBuilder(in boolean aPrivateBrowsing);
+
+  /**
+   * Retrieves a Windows Jump List builder. This jump list builder can be used
+   * to asynchronously add, remove, and update items in the Windows Jump List.
+   *
+   * @throws NS_ERROR_UNEXPECTED if the builder failed to be created.
+   */
+  nsIJumpListBuilder createJumpListBuilder(in boolean aPrivateBrowsing);
+
+  /**
+   * Application window taskbar group settings
+   */
+
+  /**
+   * Get the grouping id for a window.
+   *
+   * The runtime sets a default, global grouping id for all windows on startup.
+   * getGroupIdForWindow allows finding the grouping of individual windows
+   * on the taskbar.
+   *
+   * @throw NS_ERROR_INVALID_ARG if the window is not a valid top level window
+   * associated with a widget.
+   * @throw NS_ERROR_FAILURE if the property on the window could not be set.
+   * @throw NS_ERROR_UNEXPECTED for general failures.
+   */
+  AString getGroupIdForWindow(in mozIDOMWindow aParent);
+
+  /**
+   * Set the grouping id for a window.
+   *
+   * The runtime sets a default, global grouping id for all windows on startup.
+   * setGroupIdForWindow allows individual windows to be grouped independently
+   * on the taskbar. Ids should be unique to the app and window to insure
+   * conflicts with other pinned applications do no arise.
+   *
+   * The default group id is based on application.ini vendor, application, and
+   * version values, with a format of 'vendor.app.version'. The default can be
+   * retrieved via defaultGroupId.
+   *
+   * Note, when a window changes taskbar window stacks, it is placed at the
+   * bottom of the new stack.
+   *
+   * @throw NS_ERROR_INVALID_ARG if the window is not a valid top level window
+   * associated with a widget.
+   * @throw NS_ERROR_FAILURE if the property on the window could not be set.
+   * @throw NS_ERROR_UNEXPECTED for general failures.
+   */
+  void setGroupIdForWindow(in mozIDOMWindow aParent, in AString aIdentifier);
+
+  /**
+   * Notify the taskbar that a window identified by its HWND is about to enter
+   * full screen mode.
+   *
+   * A Windows autohide taskbar will not behave correctly in all cases if
+   * it is not notified when full screen operations start and end.
+   *
+   * @throw NS_ERROR_INVALID_ARG if the window is not a valid top level window
+   * @throw NS_ERROR_UNEXPECTED for general failures.
+   * @throw NS_ERROR_NOT_AVAILABLE if the taskbar cannot be obtained.
+   */
+  [noscript] void prepareFullScreen(in voidPtr aHWND, in boolean aFullScreen);
+};
diff --git a/widget/nsIWindowsUIUtils.idl b/widget/nsIWindowsUIUtils.idl
new file mode 100644
index 0000000000..6c84e90afd
--- /dev/null
+++ b/widget/nsIWindowsUIUtils.idl
@@ -0,0 +1,34 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface mozIDOMWindowProxy;
+interface imgIContainer;
+
+[scriptable, builtinclass, uuid(aa8a0ecf-96a1-418c-b80e-f24ae18bbedc)]
+interface nsIWindowsUIUtils : nsISupports
+{
+  readonly attribute long systemSmallIconSize;
+  readonly attribute long systemLargeIconSize;
+
+  void setWindowIcon(in mozIDOMWindowProxy aWindow, in imgIContainer aSmallIcon, in imgIContainer aLargeIcon);
+
+  void setWindowIconFromExe(in mozIDOMWindowProxy aWindow, in AString aExe, in unsigned short aIndex);
+
+  void setWindowIconNoData(in mozIDOMWindowProxy aWindow);
+
+  /**
+   * Whether the OS is currently in tablet mode. Always false on
+   * non-Windows and on versions of Windows before win10
+   */
+  readonly attribute boolean inTabletMode;
+
+  /**
+   * Share URL
+   */
+  void shareUrl(in AString shareTitle, in AString urlToShare);
+};
diff --git a/widget/nsNativeTheme.cpp b/widget/nsNativeTheme.cpp
new file mode 100644
index 0000000000..2484f802cd
--- /dev/null
+++ b/widget/nsNativeTheme.cpp
@@ -0,0 +1,580 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsNativeTheme.h"
+#include "nsIWidget.h"
+#include "mozilla/dom/Document.h"
+#include "nsIContent.h"
+#include "nsIFrame.h"
+#include "nsIScrollableFrame.h"
+#include "nsLayoutUtils.h"
+#include "nsNumberControlFrame.h"
+#include "nsPresContext.h"
+#include "nsString.h"
+#include "nsNameSpaceManager.h"
+#include "nsStyleConsts.h"
+#include "nsPIDOMWindow.h"
+#include "nsProgressFrame.h"
+#include "nsMeterFrame.h"
+#include "nsRangeFrame.h"
+#include "nsCSSRendering.h"
+#include "ImageContainer.h"
+#include "mozilla/ComputedStyle.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/HTMLBodyElement.h"
+#include "mozilla/dom/HTMLInputElement.h"
+#include "mozilla/dom/HTMLProgressElement.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/dom/DocumentInlines.h"
+#include <algorithm>
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+nsNativeTheme::nsNativeTheme() : mAnimatedContentTimeout(UINT32_MAX) {}
+
+NS_IMPL_ISUPPORTS(nsNativeTheme, nsITimerCallback, nsINamed)
+
+/* static */ ElementState nsNativeTheme::GetContentState(
+    nsIFrame* aFrame, StyleAppearance aAppearance) {
+  if (!aFrame) {
+    return ElementState();
+  }
+
+  nsIContent* frameContent = aFrame->GetContent();
+  if (!frameContent || !frameContent->IsElement()) {
+    return ElementState();
+  }
+
+  const bool isXULElement = frameContent->IsXULElement();
+  if (isXULElement) {
+    if (aAppearance == StyleAppearance::Checkbox ||
+        aAppearance == StyleAppearance::Radio ||
+        aAppearance == StyleAppearance::ToolbarbuttonDropdown ||
+        aAppearance == StyleAppearance::ButtonArrowPrevious ||
+        aAppearance == StyleAppearance::ButtonArrowNext ||
+        aAppearance == StyleAppearance::ButtonArrowUp ||
+        aAppearance == StyleAppearance::ButtonArrowDown) {
+      aFrame = aFrame->GetParent();
+      frameContent = aFrame->GetContent();
+    }
+    MOZ_ASSERT(frameContent && frameContent->IsElement());
+  }
+
+  ElementState flags = frameContent->AsElement()->StyleState();
+  nsNumberControlFrame* numberControlFrame =
+      nsNumberControlFrame::GetNumberControlFrameForSpinButton(aFrame);
+  if (numberControlFrame &&
+      numberControlFrame->GetContent()->AsElement()->StyleState().HasState(
+          ElementState::DISABLED)) {
+    flags |= ElementState::DISABLED;
+  }
+
+  if (!isXULElement) {
+    return flags;
+  }
+
+  if (CheckBooleanAttr(aFrame, nsGkAtoms::disabled)) {
+    flags |= ElementState::DISABLED;
+  }
+
+  switch (aAppearance) {
+    case StyleAppearance::Radio: {
+      if (CheckBooleanAttr(aFrame, nsGkAtoms::focused)) {
+        flags |= ElementState::FOCUS;
+        nsPIDOMWindowOuter* window =
+            aFrame->GetContent()->OwnerDoc()->GetWindow();
+        if (window && window->ShouldShowFocusRing()) {
+          flags |= ElementState::FOCUSRING;
+        }
+      }
+      if (CheckBooleanAttr(aFrame, nsGkAtoms::selected) ||
+          CheckBooleanAttr(aFrame, nsGkAtoms::checked)) {
+        flags |= ElementState::CHECKED;
+      }
+      break;
+    }
+    case StyleAppearance::Checkbox: {
+      if (CheckBooleanAttr(aFrame, nsGkAtoms::checked)) {
+        flags |= ElementState::CHECKED;
+      } else if (CheckBooleanAttr(aFrame, nsGkAtoms::indeterminate)) {
+        flags |= ElementState::INDETERMINATE;
+      }
+      break;
+    }
+    case StyleAppearance::Toolbarbutton:
+      if (CheckBooleanAttr(aFrame, nsGkAtoms::open)) {
+        flags |= ElementState::HOVER | ElementState::ACTIVE;
+      }
+      break;
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Searchfield:
+    case StyleAppearance::Textarea: {
+      if (CheckBooleanAttr(aFrame, nsGkAtoms::focused)) {
+        flags |= ElementState::FOCUS | ElementState::FOCUSRING;
+      }
+      break;
+    }
+    default:
+      break;
+  }
+
+  return flags;
+}
+
+/* static */
+bool nsNativeTheme::CheckBooleanAttr(nsIFrame* aFrame, nsAtom* aAtom) {
+  if (!aFrame) return false;
+
+  nsIContent* content = aFrame->GetContent();
+  if (!content || !content->IsElement()) return false;
+
+  if (content->IsHTMLElement()) return content->AsElement()->HasAttr(aAtom);
+
+  // For XML/XUL elements, an attribute must be equal to the literal
+  // string "true" to be counted as true.  An empty string should _not_
+  // be counted as true.
+  return content->AsElement()->AttrValueIs(kNameSpaceID_None, aAtom, u"true"_ns,
+                                           eCaseMatters);
+}
+
+/* static */
+int32_t nsNativeTheme::CheckIntAttr(nsIFrame* aFrame, nsAtom* aAtom,
+                                    int32_t defaultValue) {
+  if (!aFrame) return defaultValue;
+
+  nsIContent* content = aFrame->GetContent();
+  if (!content || !content->IsElement()) return defaultValue;
+
+  nsAutoString attr;
+  content->AsElement()->GetAttr(aAtom, attr);
+  nsresult err;
+  int32_t value = attr.ToInteger(&err);
+  if (attr.IsEmpty() || NS_FAILED(err)) return defaultValue;
+
+  return value;
+}
+
+/* static */
+double nsNativeTheme::GetProgressValue(nsIFrame* aFrame) {
+  if (!aFrame || !aFrame->GetContent()->IsHTMLElement(nsGkAtoms::progress)) {
+    return 0;
+  }
+
+  return static_cast<HTMLProgressElement*>(aFrame->GetContent())->Value();
+}
+
+/* static */
+double nsNativeTheme::GetProgressMaxValue(nsIFrame* aFrame) {
+  if (!aFrame || !aFrame->GetContent()->IsHTMLElement(nsGkAtoms::progress)) {
+    return 100;
+  }
+
+  return static_cast<HTMLProgressElement*>(aFrame->GetContent())->Max();
+}
+
+bool nsNativeTheme::IsButtonTypeMenu(nsIFrame* aFrame) {
+  if (!aFrame) return false;
+
+  nsIContent* content = aFrame->GetContent();
+  return content->IsXULElement(nsGkAtoms::button) &&
+         content->AsElement()->AttrValueIs(kNameSpaceID_None, nsGkAtoms::type,
+                                           u"menu"_ns, eCaseMatters);
+}
+
+bool nsNativeTheme::IsPressedButton(nsIFrame* aFrame) {
+  ElementState state = GetContentState(aFrame, StyleAppearance::Toolbarbutton);
+  if (state.HasState(ElementState::DISABLED)) {
+    return false;
+  }
+
+  return IsOpenButton(aFrame) ||
+         state.HasAllStates(ElementState::ACTIVE | ElementState::HOVER);
+}
+
+bool nsNativeTheme::IsWidgetStyled(nsPresContext* aPresContext,
+                                   nsIFrame* aFrame,
+                                   StyleAppearance aAppearance) {
+  // Check for specific widgets to see if HTML has overridden the style.
+  if (!aFrame) {
+    return false;
+  }
+
+  /**
+   * Progress bar appearance should be the same for the bar and the container
+   * frame. nsProgressFrame owns the logic and will tell us what we should do.
+   */
+  if (aAppearance == StyleAppearance::Progresschunk ||
+      aAppearance == StyleAppearance::ProgressBar) {
+    nsProgressFrame* progressFrame = do_QueryFrame(
+        aAppearance == StyleAppearance::Progresschunk ? aFrame->GetParent()
+                                                      : aFrame);
+    if (progressFrame) {
+      return !progressFrame->ShouldUseNativeStyle();
+    }
+  }
+
+  /**
+   * Meter bar appearance should be the same for the bar and the container
+   * frame. nsMeterFrame owns the logic and will tell us what we should do.
+   */
+  if (aAppearance == StyleAppearance::Meterchunk ||
+      aAppearance == StyleAppearance::Meter) {
+    nsMeterFrame* meterFrame = do_QueryFrame(
+        aAppearance == StyleAppearance::Meterchunk ? aFrame->GetParent()
+                                                   : aFrame);
+    if (meterFrame) {
+      return !meterFrame->ShouldUseNativeStyle();
+    }
+  }
+
+  /**
+   * An nsRangeFrame and its children are treated atomically when it
+   * comes to native theming (either all parts, or no parts, are themed).
+   * nsRangeFrame owns the logic and will tell us what we should do.
+   */
+  if (aAppearance == StyleAppearance::Range ||
+      aAppearance == StyleAppearance::RangeThumb) {
+    nsRangeFrame* rangeFrame = do_QueryFrame(
+        aAppearance == StyleAppearance::RangeThumb ? aFrame->GetParent()
+                                                   : aFrame);
+    if (rangeFrame) {
+      return !rangeFrame->ShouldUseNativeStyle();
+    }
+  }
+
+  return nsLayoutUtils::AuthorSpecifiedBorderBackgroundDisablesTheming(
+             aAppearance) &&
+         aFrame->GetContent()->IsHTMLElement() &&
+         aFrame->Style()->HasAuthorSpecifiedBorderOrBackground();
+}
+
+/* static */
+bool nsNativeTheme::IsFrameRTL(nsIFrame* aFrame) {
+  if (!aFrame) {
+    return false;
+  }
+  return aFrame->GetWritingMode().IsPhysicalRTL();
+}
+
+/* static */
+bool nsNativeTheme::IsHTMLContent(nsIFrame* aFrame) {
+  if (!aFrame) {
+    return false;
+  }
+  nsIContent* content = aFrame->GetContent();
+  return content && content->IsHTMLElement();
+}
+
+// treeheadercell:
+nsNativeTheme::TreeSortDirection nsNativeTheme::GetTreeSortDirection(
+    nsIFrame* aFrame) {
+  if (!aFrame || !aFrame->GetContent()) return eTreeSortDirection_Natural;
+
+  static Element::AttrValuesArray strings[] = {nsGkAtoms::descending,
+                                               nsGkAtoms::ascending, nullptr};
+
+  nsIContent* content = aFrame->GetContent();
+  if (content->IsElement()) {
+    switch (content->AsElement()->FindAttrValueIn(
+        kNameSpaceID_None, nsGkAtoms::sortDirection, strings, eCaseMatters)) {
+      case 0:
+        return eTreeSortDirection_Descending;
+      case 1:
+        return eTreeSortDirection_Ascending;
+    }
+  }
+
+  return eTreeSortDirection_Natural;
+}
+
+bool nsNativeTheme::IsLastTreeHeaderCell(nsIFrame* aFrame) {
+  if (!aFrame) {
+    return false;
+  }
+
+  // A tree column picker button is always the last header cell.
+  if (aFrame->GetContent()->IsXULElement(nsGkAtoms::button)) {
+    return true;
+  }
+
+  // Find the parent tree.
+  nsIContent* parent = aFrame->GetContent()->GetParent();
+  while (parent && !parent->IsXULElement(nsGkAtoms::tree)) {
+    parent = parent->GetParent();
+  }
+
+  // If the column picker is visible, this can't be the last column.
+  if (parent && !parent->AsElement()->AttrValueIs(kNameSpaceID_None,
+                                                  nsGkAtoms::hidecolumnpicker,
+                                                  u"true"_ns, eCaseMatters))
+    return false;
+
+  while ((aFrame = aFrame->GetNextSibling())) {
+    if (aFrame->GetRect().Width() > 0) return false;
+  }
+  return true;
+}
+
+// tab:
+bool nsNativeTheme::IsBottomTab(nsIFrame* aFrame) {
+  if (!aFrame) return false;
+
+  nsAutoString classStr;
+  if (aFrame->GetContent()->IsElement()) {
+    aFrame->GetContent()->AsElement()->GetAttr(nsGkAtoms::_class, classStr);
+  }
+  // FIXME: This looks bogus, shouldn't this be looking at GetClasses()?
+  return !classStr.IsEmpty() && classStr.Find(u"tab-bottom") != kNotFound;
+}
+
+bool nsNativeTheme::IsFirstTab(nsIFrame* aFrame) {
+  if (!aFrame) return false;
+
+  for (nsIFrame* first : aFrame->GetParent()->PrincipalChildList()) {
+    if (first->GetRect().Width() > 0 &&
+        first->GetContent()->IsXULElement(nsGkAtoms::tab))
+      return (first == aFrame);
+  }
+  return false;
+}
+
+bool nsNativeTheme::IsHorizontal(nsIFrame* aFrame) {
+  if (!aFrame) return false;
+
+  if (!aFrame->GetContent()->IsElement()) return true;
+
+  return !aFrame->GetContent()->AsElement()->AttrValueIs(
+      kNameSpaceID_None, nsGkAtoms::orient, nsGkAtoms::vertical, eCaseMatters);
+}
+
+bool nsNativeTheme::IsNextToSelectedTab(nsIFrame* aFrame, int32_t aOffset) {
+  if (!aFrame) return false;
+
+  if (aOffset == 0) return IsSelectedTab(aFrame);
+
+  int32_t thisTabIndex = -1, selectedTabIndex = -1;
+
+  nsIFrame* currentTab = aFrame->GetParent()->PrincipalChildList().FirstChild();
+  for (int32_t i = 0; currentTab; currentTab = currentTab->GetNextSibling()) {
+    if (currentTab->GetRect().Width() == 0) continue;
+    if (aFrame == currentTab) thisTabIndex = i;
+    if (IsSelectedTab(currentTab)) selectedTabIndex = i;
+    ++i;
+  }
+
+  if (thisTabIndex == -1 || selectedTabIndex == -1) return false;
+
+  return (thisTabIndex - selectedTabIndex == aOffset);
+}
+
+bool nsNativeTheme::IsVerticalProgress(nsIFrame* aFrame) {
+  if (!aFrame) {
+    return false;
+  }
+  return IsVerticalMeter(aFrame);
+}
+
+bool nsNativeTheme::IsVerticalMeter(nsIFrame* aFrame) {
+  MOZ_ASSERT(aFrame, "You have to pass a non-null aFrame");
+  switch (aFrame->StyleDisplay()->mOrient) {
+    case StyleOrient::Horizontal:
+      return false;
+    case StyleOrient::Vertical:
+      return true;
+    case StyleOrient::Inline:
+      return aFrame->GetWritingMode().IsVertical();
+    case StyleOrient::Block:
+      return !aFrame->GetWritingMode().IsVertical();
+  }
+  MOZ_ASSERT_UNREACHABLE("unexpected -moz-orient value");
+  return false;
+}
+
+// menupopup:
+bool nsNativeTheme::IsSubmenu(nsIFrame* aFrame, bool* aLeftOfParent) {
+  if (!aFrame) return false;
+
+  nsIContent* parentContent = aFrame->GetContent()->GetParent();
+  if (!parentContent || !parentContent->IsXULElement(nsGkAtoms::menu))
+    return false;
+
+  nsIFrame* parent = aFrame;
+  while ((parent = parent->GetParent())) {
+    if (parent->GetContent() == parentContent) {
+      if (aLeftOfParent) {
+        LayoutDeviceIntRect selfBounds, parentBounds;
+        selfBounds = aFrame->GetNearestWidget()->GetScreenBounds();
+        parentBounds = parent->GetNearestWidget()->GetScreenBounds();
+        *aLeftOfParent = selfBounds.X() < parentBounds.X();
+      }
+      return true;
+    }
+  }
+
+  return false;
+}
+
+bool nsNativeTheme::QueueAnimatedContentForRefresh(nsIContent* aContent,
+                                                   uint32_t aMinimumFrameRate) {
+  NS_ASSERTION(aContent, "Null pointer!");
+  NS_ASSERTION(aMinimumFrameRate, "aMinimumFrameRate must be non-zero!");
+  NS_ASSERTION(aMinimumFrameRate <= 1000,
+               "aMinimumFrameRate must be less than 1000!");
+
+  uint32_t timeout = 1000 / aMinimumFrameRate;
+  timeout = std::min(mAnimatedContentTimeout, timeout);
+
+  if (!mAnimatedContentTimer) {
+    mAnimatedContentTimer = NS_NewTimer();
+    NS_ENSURE_TRUE(mAnimatedContentTimer, false);
+  }
+
+  if (mAnimatedContentList.IsEmpty() || timeout != mAnimatedContentTimeout) {
+    nsresult rv;
+    if (!mAnimatedContentList.IsEmpty()) {
+      rv = mAnimatedContentTimer->Cancel();
+      NS_ENSURE_SUCCESS(rv, false);
+    }
+
+    if (XRE_IsContentProcess() && NS_IsMainThread()) {
+      mAnimatedContentTimer->SetTarget(GetMainThreadSerialEventTarget());
+    }
+    rv = mAnimatedContentTimer->InitWithCallback(this, timeout,
+                                                 nsITimer::TYPE_ONE_SHOT);
+    NS_ENSURE_SUCCESS(rv, false);
+
+    mAnimatedContentTimeout = timeout;
+  }
+
+  // XXX(Bug 1631371) Check if this should use a fallible operation as it
+  // pretended earlier.
+  mAnimatedContentList.AppendElement(aContent);
+
+  return true;
+}
+
+NS_IMETHODIMP
+nsNativeTheme::Notify(nsITimer* aTimer) {
+  NS_ASSERTION(aTimer == mAnimatedContentTimer, "Wrong timer!");
+
+  // XXX Assumes that calling nsIFrame::Invalidate won't reenter
+  //     QueueAnimatedContentForRefresh.
+
+  uint32_t count = mAnimatedContentList.Length();
+  for (uint32_t index = 0; index < count; index++) {
+    nsIFrame* frame = mAnimatedContentList[index]->GetPrimaryFrame();
+    if (frame) {
+      frame->InvalidateFrame();
+    }
+  }
+
+  mAnimatedContentList.Clear();
+  mAnimatedContentTimeout = UINT32_MAX;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNativeTheme::GetName(nsACString& aName) {
+  aName.AssignLiteral("nsNativeTheme");
+  return NS_OK;
+}
+
+nsIFrame* nsNativeTheme::GetAdjacentSiblingFrameWithSameAppearance(
+    nsIFrame* aFrame, bool aNextSibling) {
+  if (!aFrame) return nullptr;
+
+  // Find the next visible sibling.
+  nsIFrame* sibling = aFrame;
+  do {
+    sibling =
+        aNextSibling ? sibling->GetNextSibling() : sibling->GetPrevSibling();
+  } while (sibling && sibling->GetRect().Width() == 0);
+
+  // Check same appearance and adjacency.
+  if (!sibling ||
+      sibling->StyleDisplay()->EffectiveAppearance() !=
+          aFrame->StyleDisplay()->EffectiveAppearance() ||
+      (sibling->GetRect().XMost() != aFrame->GetRect().X() &&
+       aFrame->GetRect().XMost() != sibling->GetRect().X()))
+    return nullptr;
+  return sibling;
+}
+
+bool nsNativeTheme::IsRangeHorizontal(nsIFrame* aFrame) {
+  nsIFrame* rangeFrame = aFrame;
+  if (!rangeFrame->IsRangeFrame()) {
+    // If the thumb's frame is passed in, get its range parent:
+    rangeFrame = aFrame->GetParent();
+  }
+  if (rangeFrame->IsRangeFrame()) {
+    return static_cast<nsRangeFrame*>(rangeFrame)->IsHorizontal();
+  }
+  // Not actually a range frame - just use the ratio of the frame's size to
+  // decide:
+  return aFrame->GetSize().width >= aFrame->GetSize().height;
+}
+
+/* static */
+bool nsNativeTheme::IsDarkBackgroundForScrollbar(nsIFrame* aFrame) {
+  // Try to find the scrolled frame. Note that for stuff like xul <tree> there
+  // might be none.
+  {
+    nsIFrame* frame = aFrame;
+    nsIScrollableFrame* scrollFrame = nullptr;
+    while (!scrollFrame && frame) {
+      scrollFrame = frame->GetScrollTargetFrame();
+      frame = frame->GetParent();
+    }
+    if (scrollFrame) {
+      aFrame = scrollFrame->GetScrolledFrame();
+    } else {
+      // Leave aFrame untouched.
+    }
+  }
+
+  return IsDarkBackground(aFrame);
+}
+
+/* static */
+bool nsNativeTheme::IsDarkBackground(nsIFrame* aFrame) {
+  auto color =
+      nsCSSRendering::FindEffectiveBackgroundColor(
+          aFrame, /* aStopAtThemed = */ false, /* aPreferBodyToCanvas = */ true)
+          .mColor;
+  return LookAndFeel::IsDarkColor(color);
+}
+
+/*static*/
+bool nsNativeTheme::IsWidgetScrollbarPart(StyleAppearance aAppearance) {
+  switch (aAppearance) {
+    case StyleAppearance::ScrollbarVertical:
+    case StyleAppearance::ScrollbarHorizontal:
+    case StyleAppearance::ScrollbarbuttonUp:
+    case StyleAppearance::ScrollbarbuttonDown:
+    case StyleAppearance::ScrollbarbuttonLeft:
+    case StyleAppearance::ScrollbarbuttonRight:
+    case StyleAppearance::ScrollbarthumbVertical:
+    case StyleAppearance::ScrollbarthumbHorizontal:
+    case StyleAppearance::ScrollbartrackHorizontal:
+    case StyleAppearance::ScrollbartrackVertical:
+    case StyleAppearance::Scrollcorner:
+      return true;
+    default:
+      return false;
+  }
+}
+
+/*static*/
+bool nsNativeTheme::IsWidgetAlwaysNonNative(nsIFrame* aFrame,
+                                            StyleAppearance aAppearance) {
+  return IsWidgetScrollbarPart(aAppearance) ||
+         aAppearance == StyleAppearance::FocusOutline ||
+         (aFrame && aFrame->StyleUI()->mMozTheme == StyleMozTheme::NonNative);
+}
diff --git a/widget/nsNativeTheme.h b/widget/nsNativeTheme.h
new file mode 100644
index 0000000000..28a8c0cc3f
--- /dev/null
+++ b/widget/nsNativeTheme.h
@@ -0,0 +1,170 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This defines a common base class for nsITheme implementations, to reduce
+// code duplication.
+
+#ifndef _NSNATIVETHEME_H_
+#define _NSNATIVETHEME_H_
+
+#include "nsAlgorithm.h"
+#include "nsAtom.h"
+#include "nsColor.h"
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "nsMargin.h"
+#include "nsGkAtoms.h"
+#include "nsTArray.h"
+#include "nsINamed.h"
+#include "nsITimer.h"
+#include "nsIContent.h"
+#include "mozilla/dom/RustTypes.h"
+
+class nsIFrame;
+class nsPresContext;
+
+namespace mozilla {
+class ComputedStyle;
+enum class StyleAppearance : uint8_t;
+}  // namespace mozilla
+
+class nsNativeTheme : public nsITimerCallback, public nsINamed {
+ protected:
+  virtual ~nsNativeTheme() = default;
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITIMERCALLBACK
+  NS_DECL_NSINAMED
+
+  nsNativeTheme();
+
+ public:
+  enum ScrollbarButtonType {
+    eScrollbarButton_UpTop = 0,
+    eScrollbarButton_Down = 1 << 0,
+    eScrollbarButton_Bottom = 1 << 1
+  };
+
+  enum TreeSortDirection {
+    eTreeSortDirection_Descending,
+    eTreeSortDirection_Natural,
+    eTreeSortDirection_Ascending
+  };
+  // Returns the content state (hover, focus, etc), see EventStateManager.h
+  static mozilla::dom::ElementState GetContentState(
+      nsIFrame* aFrame, mozilla::StyleAppearance aAppearance);
+
+  // Returns whether the widget is already styled by content
+  // Normally called from ThemeSupportsWidget to turn off native theming
+  // for elements that are already styled.
+  bool IsWidgetStyled(nsPresContext* aPresContext, nsIFrame* aFrame,
+                      mozilla::StyleAppearance aAppearance);
+
+  // RTL chrome direction
+  static bool IsFrameRTL(nsIFrame* aFrame);
+
+  static bool IsHTMLContent(nsIFrame* aFrame);
+
+  // button:
+  bool IsDefaultButton(nsIFrame* aFrame) {
+    return CheckBooleanAttr(aFrame, nsGkAtoms::_default);
+  }
+
+  bool IsButtonTypeMenu(nsIFrame* aFrame);
+
+  // tab:
+  bool IsSelectedTab(nsIFrame* aFrame) {
+    return CheckBooleanAttr(aFrame, nsGkAtoms::visuallyselected);
+  }
+
+  bool IsNextToSelectedTab(nsIFrame* aFrame, int32_t aOffset);
+
+  bool IsBeforeSelectedTab(nsIFrame* aFrame) {
+    return IsNextToSelectedTab(aFrame, -1);
+  }
+
+  bool IsAfterSelectedTab(nsIFrame* aFrame) {
+    return IsNextToSelectedTab(aFrame, 1);
+  }
+
+  bool IsLeftToSelectedTab(nsIFrame* aFrame) {
+    return IsFrameRTL(aFrame) ? IsAfterSelectedTab(aFrame)
+                              : IsBeforeSelectedTab(aFrame);
+  }
+
+  bool IsRightToSelectedTab(nsIFrame* aFrame) {
+    return IsFrameRTL(aFrame) ? IsBeforeSelectedTab(aFrame)
+                              : IsAfterSelectedTab(aFrame);
+  }
+
+  // button / toolbarbutton:
+  bool IsCheckedButton(nsIFrame* aFrame) {
+    return CheckBooleanAttr(aFrame, nsGkAtoms::checked);
+  }
+
+  bool IsSelectedButton(nsIFrame* aFrame) {
+    return CheckBooleanAttr(aFrame, nsGkAtoms::checked) ||
+           CheckBooleanAttr(aFrame, nsGkAtoms::selected);
+  }
+
+  bool IsOpenButton(nsIFrame* aFrame) {
+    return CheckBooleanAttr(aFrame, nsGkAtoms::open);
+  }
+
+  bool IsPressedButton(nsIFrame* aFrame);
+
+  // treeheadercell:
+  TreeSortDirection GetTreeSortDirection(nsIFrame* aFrame);
+  bool IsLastTreeHeaderCell(nsIFrame* aFrame);
+
+  // tab:
+  bool IsBottomTab(nsIFrame* aFrame);
+  bool IsFirstTab(nsIFrame* aFrame);
+
+  bool IsHorizontal(nsIFrame* aFrame);
+
+  // progressbar:
+  bool IsVerticalProgress(nsIFrame* aFrame);
+
+  // meter:
+  bool IsVerticalMeter(nsIFrame* aFrame);
+
+  // textfield:
+  bool IsReadOnly(nsIFrame* aFrame) {
+    return CheckBooleanAttr(aFrame, nsGkAtoms::readonly);
+  }
+
+  // menupopup:
+  bool IsSubmenu(nsIFrame* aFrame, bool* aLeftOfParent);
+
+  static bool CheckBooleanAttr(nsIFrame* aFrame, nsAtom* aAtom);
+  static int32_t CheckIntAttr(nsIFrame* aFrame, nsAtom* aAtom,
+                              int32_t defaultValue);
+
+  // Helpers for progressbar.
+  static double GetProgressValue(nsIFrame* aFrame);
+  static double GetProgressMaxValue(nsIFrame* aFrame);
+
+  bool QueueAnimatedContentForRefresh(nsIContent* aContent,
+                                      uint32_t aMinimumFrameRate);
+
+  nsIFrame* GetAdjacentSiblingFrameWithSameAppearance(nsIFrame* aFrame,
+                                                      bool aNextSibling);
+
+  bool IsRangeHorizontal(nsIFrame* aFrame);
+
+  static bool IsDarkBackgroundForScrollbar(nsIFrame*);
+  static bool IsDarkBackground(nsIFrame*);
+
+  static bool IsWidgetScrollbarPart(mozilla::StyleAppearance);
+  static bool IsWidgetAlwaysNonNative(nsIFrame*, mozilla::StyleAppearance);
+
+ private:
+  uint32_t mAnimatedContentTimeout;
+  nsCOMPtr<nsITimer> mAnimatedContentTimer;
+  AutoTArray<nsCOMPtr<nsIContent>, 20> mAnimatedContentList;
+};
+
+#endif  // _NSNATIVETHEME_H_
diff --git a/widget/nsPaper.cpp b/widget/nsPaper.cpp
new file mode 100644
index 0000000000..a940d3c1cb
--- /dev/null
+++ b/widget/nsPaper.cpp
@@ -0,0 +1,87 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPaper.h"
+#include "nsPaperMargin.h"
+#include "nsPrinterBase.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/dom/Promise.h"
+
+using mozilla::ErrorResult;
+using mozilla::PaperInfo;
+
+NS_IMPL_CYCLE_COLLECTION(nsPaper, mMarginPromise, mPrinter)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsPaper)
+  NS_INTERFACE_MAP_ENTRY(nsIPaper)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIPaper)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsPaper)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsPaper)
+
+nsPaper::nsPaper(const mozilla::PaperInfo& aInfo)
+    : mPrinter(nullptr), mInfo(aInfo) {}
+
+nsPaper::nsPaper(nsPrinterBase& aPrinter, const mozilla::PaperInfo& aInfo)
+    : mPrinter(&aPrinter), mInfo(aInfo) {}
+
+nsPaper::~nsPaper() = default;
+
+NS_IMETHODIMP
+nsPaper::GetId(nsAString& aId) {
+  aId = mInfo.mId;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPaper::GetName(nsAString& aName) {
+  aName = mInfo.mName.IsEmpty() ? mInfo.mId : mInfo.mName;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPaper::GetWidth(double* aWidth) {
+  NS_ENSURE_ARG_POINTER(aWidth);
+  *aWidth = mInfo.mSize.Width();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPaper::GetHeight(double* aHeight) {
+  NS_ENSURE_ARG_POINTER(aHeight);
+  *aHeight = mInfo.mSize.Height();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPaper::GetUnwriteableMargin(JSContext* aCx, Promise** aPromise) {
+  if (RefPtr<Promise> existing = mMarginPromise) {
+    existing.forget(aPromise);
+    return NS_OK;
+  }
+  ErrorResult rv;
+  RefPtr<Promise> promise = Promise::Create(xpc::CurrentNativeGlobal(aCx), rv);
+  if (MOZ_UNLIKELY(rv.Failed())) {
+    return rv.StealNSResult();
+  }
+
+  mMarginPromise = promise;
+
+  if (mInfo.mUnwriteableMargin) {
+    auto margin = mozilla::MakeRefPtr<nsPaperMargin>(*mInfo.mUnwriteableMargin);
+    mMarginPromise->MaybeResolve(margin);
+  } else {
+    if (mPrinter) {
+      mPrinter->QueryMarginsForPaper(*mMarginPromise, mInfo.mId);
+    } else {
+      MOZ_ASSERT_UNREACHABLE("common paper sizes should know their margins");
+      mMarginPromise->MaybeRejectWithNotSupportedError("Margins unavailable");
+    }
+  }
+
+  promise.forget(aPromise);
+  return NS_OK;
+}
diff --git a/widget/nsPaper.h b/widget/nsPaper.h
new file mode 100644
index 0000000000..b0117b7306
--- /dev/null
+++ b/widget/nsPaper.h
@@ -0,0 +1,128 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPaper_h__
+#define nsPaper_h__
+
+#include "mozilla/dom/ToJSValue.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/gfx/Rect.h"
+#include "mozilla/Maybe.h"
+#include "nsIPaper.h"
+#include "nsISupportsImpl.h"
+#include "js/TypeDecls.h"
+#include "nsString.h"
+
+struct JSContext;
+
+namespace mozilla {
+
+// Simple struct that can be used off the main thread to hold all the info from
+// an nsPaper instance.
+struct PaperInfo {
+  using MarginDouble = mozilla::gfx::MarginDouble;
+  using SizeDouble = mozilla::gfx::SizeDouble;
+
+  PaperInfo() = default;
+  PaperInfo(const nsAString& aId, const nsAString& aName,
+            const SizeDouble& aSize,
+            const Maybe<MarginDouble>& aUnwriteableMargin)
+      : mId(aId),
+        mName(aName),
+        mSize(aSize),
+        mUnwriteableMargin(aUnwriteableMargin) {}
+
+  nsString mId;
+  nsString mName;
+
+  SizeDouble mSize;
+
+  // The margins may not be known by some back-ends.
+  Maybe<MarginDouble> mUnwriteableMargin{Nothing()};
+};
+
+/**
+ * Plain struct used for commonly used, hard-coded paper sizes.
+ *
+ * Used to construct PaperInfo at runtime by localizing the name.
+ */
+struct CommonPaperSize final {
+  // The standardized PWG name, which should be used as the PaperInfo id
+  nsLiteralString mPWGName;
+  // The name key to localize the name of this paper size using strings in
+  // printUI.ftl
+  nsLiteralCString mLocalizableNameKey;
+  // Size is in points, same as PaperInfo
+  gfx::SizeDouble mSize;
+};
+
+}  // namespace mozilla
+
+class nsPrinterBase;
+
+class nsPaper final : public nsIPaper {
+  using Promise = mozilla::dom::Promise;
+  using CommonPaperSize = mozilla::CommonPaperSize;
+
+ public:
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS(nsPaper)
+  NS_DECL_NSIPAPER
+
+  nsPaper() = delete;
+  explicit nsPaper(const mozilla::PaperInfo&);
+  nsPaper(nsPrinterBase&, const mozilla::PaperInfo&);
+
+  // This list is used for both our fallback paper sizes (used when a printer
+  // does not provide a list of available paper sizes), and for localizing
+  // common paper sizes to avoid querying the printer for extra information in
+  // the common case, as well as to provide more uniform paper names in the
+  // frontend.
+  // If we need to separate these two uses, we will need to either split this
+  // into two lists, or add a flag to indicate what the size is used for.
+#define mm *72.0 / 25.4
+#define in *72.0
+  static constexpr CommonPaperSize kCommonPaperSizes[] = {
+      CommonPaperSize{u"iso_a5"_ns, "a5"_ns, {148 mm, 210 mm}},
+      CommonPaperSize{u"iso_a4"_ns, "a4"_ns, {210 mm, 297 mm}},
+      CommonPaperSize{u"iso_a3"_ns, "a3"_ns, {297 mm, 420 mm}},
+      CommonPaperSize{u"iso_b5"_ns, "b5"_ns, {176 mm, 250 mm}},
+      CommonPaperSize{u"iso_b4"_ns, "b4"_ns, {250 mm, 353 mm}},
+      CommonPaperSize{u"jis_b5"_ns, "jis-b5"_ns, {182 mm, 257 mm}},
+      CommonPaperSize{u"jis_b4"_ns, "jis-b4"_ns, {257 mm, 364 mm}},
+      CommonPaperSize{u"na_letter"_ns, "letter"_ns, {8.5 in, 11 in}},
+      CommonPaperSize{u"na_legal"_ns, "legal"_ns, {8.5 in, 14 in}},
+      CommonPaperSize{u"na_ledger"_ns, "tabloid"_ns, {11 in, 17 in}}};
+#undef mm
+#undef in
+  static constexpr size_t kNumCommonPaperSizes =
+      mozilla::ArrayLength(kCommonPaperSizes);
+
+ private:
+  ~nsPaper();
+
+  // null if not associated with a printer (for "Save-to-PDF" paper sizes)
+  RefPtr<nsPrinterBase> mPrinter;
+
+  RefPtr<Promise> mMarginPromise;
+  const mozilla::PaperInfo mInfo;
+};
+
+namespace mozilla {
+
+// Used to allow fixed-sized arrays of PWG paper info to be ref-counted.
+class CommonPaperInfoArray
+    : public Array<PaperInfo, nsPaper::kNumCommonPaperSizes> {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CommonPaperInfoArray);
+  CommonPaperInfoArray() = default;
+
+ private:
+  ~CommonPaperInfoArray() = default;
+};
+
+}  // namespace mozilla
+
+#endif /* nsPaper_h__ */
diff --git a/widget/nsPaperMargin.cpp b/widget/nsPaperMargin.cpp
new file mode 100644
index 0000000000..1e6171cd16
--- /dev/null
+++ b/widget/nsPaperMargin.cpp
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPaperMargin.h"
+
+NS_IMPL_ISUPPORTS(nsPaperMargin, nsIPaperMargin)
+
+NS_IMETHODIMP
+nsPaperMargin::GetTop(double* aTop) {
+  *aTop = mMargin.top;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPaperMargin::GetRight(double* aRight) {
+  *aRight = mMargin.right;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPaperMargin::GetBottom(double* aBottom) {
+  *aBottom = mMargin.bottom;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPaperMargin::GetLeft(double* aLeft) {
+  *aLeft = mMargin.left;
+  return NS_OK;
+}
diff --git a/widget/nsPaperMargin.h b/widget/nsPaperMargin.h
new file mode 100644
index 0000000000..594b266c00
--- /dev/null
+++ b/widget/nsPaperMargin.h
@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPaperMargin_h_
+#define nsPaperMargin_h_
+
+#include "nsISupportsImpl.h"
+#include "nsIPaperMargin.h"
+#include "mozilla/gfx/Rect.h"
+
+class nsPaperMargin final : public nsIPaperMargin {
+  using MarginDouble = mozilla::gfx::MarginDouble;
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIPAPERMARGIN
+
+  nsPaperMargin() = delete;
+
+  explicit nsPaperMargin(const MarginDouble& aMargin) : mMargin(aMargin) {}
+
+ private:
+  ~nsPaperMargin() = default;
+  const MarginDouble mMargin;
+};
+
+#endif
diff --git a/widget/nsPrimitiveHelpers.cpp b/widget/nsPrimitiveHelpers.cpp
new file mode 100644
index 0000000000..ea36f32d72
--- /dev/null
+++ b/widget/nsPrimitiveHelpers.cpp
@@ -0,0 +1,193 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//
+// Part of the reason these routines are all in once place is so that as new
+// data flavors are added that are known to be one-byte or two-byte strings, or
+// even raw binary data, then we just have to go to one place to change how the
+// data moves into/out of the primitives and native line endings.
+//
+// If you add new flavors that have special consideration (binary data or
+// one-byte char* strings), please update all the helper classes in this file.
+//
+// For now, this is the assumption that we are making:
+//  - text/plain is always a char*
+//  - anything else is a char16_t*
+//
+
+#include "nsPrimitiveHelpers.h"
+
+#include "mozilla/UniquePtr.h"
+#include "nsComponentManagerUtils.h"
+#include "nsCOMPtr.h"
+#include "nsXPCOM.h"
+#include "nsISupportsPrimitives.h"
+#include "nsITransferable.h"
+#include "nsLinebreakConverter.h"
+#include "nsReadableUtils.h"
+
+//
+// CreatePrimitiveForData
+//
+// Given some data and the flavor it corresponds to, creates the appropriate
+// nsISupports* wrapper for passing across IDL boundaries. Right now, everything
+// creates a two-byte |nsISupportsString|, except for "text/plain" and native
+// platform HTML (CF_HTML on win32)
+//
+void nsPrimitiveHelpers ::CreatePrimitiveForData(const nsACString& aFlavor,
+                                                 const void* aDataBuff,
+                                                 uint32_t aDataLen,
+                                                 nsISupports** aPrimitive) {
+  if (!aPrimitive) return;
+
+  if (aFlavor.EqualsLiteral(kNativeHTMLMime) ||
+      aFlavor.EqualsLiteral(kRTFMime) ||
+      aFlavor.EqualsLiteral(kCustomTypesMime)) {
+    nsCOMPtr<nsISupportsCString> primitive =
+        do_CreateInstance(NS_SUPPORTS_CSTRING_CONTRACTID);
+    if (primitive) {
+      const char* start = reinterpret_cast<const char*>(aDataBuff);
+      primitive->SetData(Substring(start, start + aDataLen));
+      NS_ADDREF(*aPrimitive = primitive);
+    }
+  } else {
+    nsCOMPtr<nsISupportsString> primitive =
+        do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID);
+    if (primitive) {
+      if (aDataLen % 2) {
+        auto buffer = mozilla::MakeUnique<char[]>(aDataLen + 1);
+        if (!MOZ_LIKELY(buffer)) return;
+
+        memcpy(buffer.get(), aDataBuff, aDataLen);
+        buffer[aDataLen] = 0;
+        const char16_t* start = reinterpret_cast<const char16_t*>(buffer.get());
+        // recall that length takes length as characters, not bytes
+        primitive->SetData(Substring(start, start + (aDataLen + 1) / 2));
+      } else {
+        const char16_t* start = reinterpret_cast<const char16_t*>(aDataBuff);
+        // recall that length takes length as characters, not bytes
+        primitive->SetData(Substring(start, start + (aDataLen / 2)));
+      }
+      NS_ADDREF(*aPrimitive = primitive);
+    }
+  }
+
+}  // CreatePrimitiveForData
+
+//
+// CreatePrimitiveForCFHTML
+//
+// Platform specific CreatePrimitive, windows CF_HTML.
+//
+void nsPrimitiveHelpers ::CreatePrimitiveForCFHTML(const void* aDataBuff,
+                                                   uint32_t* aDataLen,
+                                                   nsISupports** aPrimitive) {
+  if (!aPrimitive) return;
+
+  nsCOMPtr<nsISupportsString> primitive =
+      do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID);
+  if (!primitive) return;
+
+  // We need to duplicate the input buffer, since the removal of linebreaks
+  // might reallocte it.
+  void* utf8 = moz_xmalloc(*aDataLen);
+  memcpy(utf8, aDataBuff, *aDataLen);
+  int32_t signedLen = static_cast<int32_t>(*aDataLen);
+  nsLinebreakHelpers::ConvertPlatformToDOMLinebreaks(true, &utf8, &signedLen);
+  *aDataLen = signedLen;
+
+  nsAutoString str(
+      NS_ConvertUTF8toUTF16(reinterpret_cast<const char*>(utf8), *aDataLen));
+  free(utf8);
+  *aDataLen = str.Length() * sizeof(char16_t);
+  primitive->SetData(str);
+  NS_ADDREF(*aPrimitive = primitive);
+}
+
+//
+// CreateDataFromPrimitive
+//
+// Given a nsISupports* primitive and the flavor it represents, creates a new
+// data buffer with the data in it. This data will be null terminated, but the
+// length parameter does not reflect that.
+//
+void nsPrimitiveHelpers::CreateDataFromPrimitive(const nsACString& aFlavor,
+                                                 nsISupports* aPrimitive,
+                                                 void** aDataBuff,
+                                                 uint32_t* aDataLen) {
+  if (!aDataBuff) return;
+
+  *aDataBuff = nullptr;
+  *aDataLen = 0;
+
+  if (aFlavor.EqualsLiteral(kCustomTypesMime)) {
+    nsCOMPtr<nsISupportsCString> plainText(do_QueryInterface(aPrimitive));
+    if (plainText) {
+      nsAutoCString data;
+      plainText->GetData(data);
+      *aDataBuff = ToNewCString(data);
+      *aDataLen = data.Length() * sizeof(char);
+    }
+  } else {
+    nsCOMPtr<nsISupportsString> doubleByteText(do_QueryInterface(aPrimitive));
+    if (doubleByteText) {
+      nsAutoString data;
+      doubleByteText->GetData(data);
+      *aDataBuff = ToNewUnicode(data);
+      *aDataLen = data.Length() * sizeof(char16_t);
+    }
+  }
+}
+
+//
+// ConvertPlatformToDOMLinebreaks
+//
+// Given some data, convert from the platform linebreaks into the LF expected by
+// the DOM. This will attempt to convert the data in place, but the buffer may
+// still need to be reallocated regardless (disposing the old buffer is taken
+// care of internally, see the note below).
+//
+// NOTE: this assumes that it can use 'free' to dispose of the old buffer.
+//
+nsresult nsLinebreakHelpers ::ConvertPlatformToDOMLinebreaks(
+    bool aIsSingleByteChars, void** ioData, int32_t* ioLengthInBytes) {
+  NS_ASSERTION(ioData && *ioData && ioLengthInBytes, "Bad Params");
+  if (!(ioData && *ioData && ioLengthInBytes)) return NS_ERROR_INVALID_ARG;
+
+  nsresult retVal = NS_OK;
+
+  // RTF and CF_HTML on Windows are transfered as single-byte characters.
+  if (aIsSingleByteChars) {
+    char* buffAsChars = reinterpret_cast<char*>(*ioData);
+    char* oldBuffer = buffAsChars;
+    retVal = nsLinebreakConverter::ConvertLineBreaksInSitu(
+        &buffAsChars, nsLinebreakConverter::eLinebreakAny,
+        nsLinebreakConverter::eLinebreakContent, *ioLengthInBytes,
+        ioLengthInBytes);
+    if (NS_SUCCEEDED(retVal)) {
+      if (buffAsChars != oldBuffer)  // check if buffer was reallocated
+        free(oldBuffer);
+      *ioData = buffAsChars;
+    }
+  } else {
+    char16_t* buffAsUnichar = reinterpret_cast<char16_t*>(*ioData);
+    char16_t* oldBuffer = buffAsUnichar;
+    int32_t newLengthInChars;
+    retVal = nsLinebreakConverter::ConvertUnicharLineBreaksInSitu(
+        &buffAsUnichar, nsLinebreakConverter::eLinebreakAny,
+        nsLinebreakConverter::eLinebreakContent,
+        *ioLengthInBytes / sizeof(char16_t), &newLengthInChars);
+    if (NS_SUCCEEDED(retVal)) {
+      if (buffAsUnichar != oldBuffer)  // check if buffer was reallocated
+        free(oldBuffer);
+      *ioData = buffAsUnichar;
+      *ioLengthInBytes = newLengthInChars * sizeof(char16_t);
+    }
+  }
+
+  return retVal;
+
+}  // ConvertPlatformToDOMLinebreaks
diff --git a/widget/nsPrimitiveHelpers.h b/widget/nsPrimitiveHelpers.h
new file mode 100644
index 0000000000..54a903b444
--- /dev/null
+++ b/widget/nsPrimitiveHelpers.h
@@ -0,0 +1,54 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrimitiveHelpers_h___
+#define nsPrimitiveHelpers_h___
+
+#include "nsError.h"
+#include "nscore.h"
+#include "nsString.h"
+
+class nsISupports;
+
+class nsPrimitiveHelpers {
+ public:
+  // Given some data and the flavor it corresponds to, creates the appropriate
+  // nsISupports* wrapper for passing across IDL boundaries. The length
+  // parameter should not include the null if the data is null terminated.
+  static void CreatePrimitiveForData(const nsACString& aFlavor,
+                                     const void* aDataBuff, uint32_t aDataLen,
+                                     nsISupports** aPrimitive);
+
+  // A specific case of CreatePrimitive for windows CF_HTML handling in
+  // DataTransfer
+  static void CreatePrimitiveForCFHTML(const void* aDataBuff,
+                                       uint32_t* aDataLen,
+                                       nsISupports** aPrimitive);
+
+  // Given a nsISupports* primitive and the flavor it represents, creates a new
+  // data buffer with the data in it. This data will be null terminated, but the
+  // length parameter does not reflect that.
+  static void CreateDataFromPrimitive(const nsACString& aFlavor,
+                                      nsISupports* aPrimitive, void** aDataBuff,
+                                      uint32_t* aDataLen);
+
+};  // class nsPrimitiveHelpers
+
+class nsLinebreakHelpers {
+ public:
+  // Given some data, convert from the platform linebreaks into the LF expected
+  // by the DOM. This will attempt to convert the data in place, but the buffer
+  // may still need to be reallocated regardless (disposing the old buffer is
+  // taken care of internally, see the note below).
+  //
+  // NOTE: this assumes that it can use 'free' to dispose of the old buffer.
+  static nsresult ConvertPlatformToDOMLinebreaks(bool aIsSingleByteChars,
+                                                 void** ioData,
+                                                 int32_t* ioLengthInBytes);
+
+};  // class nsLinebreakHelpers
+
+#endif  // nsPrimitiveHelpers_h___
diff --git a/widget/nsPrintSettingsImpl.cpp b/widget/nsPrintSettingsImpl.cpp
new file mode 100644
index 0000000000..45623af88a
--- /dev/null
+++ b/widget/nsPrintSettingsImpl.cpp
@@ -0,0 +1,941 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrintSettingsImpl.h"
+
+#include "prenv.h"
+#include "nsCoord.h"
+#include "nsPaper.h"
+#include "nsReadableUtils.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/RefPtr.h"
+
+using namespace mozilla;
+
+#define DEFAULT_MARGIN_WIDTH 0.5
+
+NS_IMPL_ISUPPORTS(nsPrintSettings, nsIPrintSettings)
+
+nsPrintSettings::nsPrintSettings() {
+  /* member initializers and constructor code */
+  int32_t marginWidth = NS_INCHES_TO_INT_TWIPS(DEFAULT_MARGIN_WIDTH);
+  mMargin.SizeTo(marginWidth, marginWidth, marginWidth, marginWidth);
+  mEdge.SizeTo(0, 0, 0, 0);
+  mUnwriteableMargin.SizeTo(0, 0, 0, 0);
+
+  mHeaderStrs[0].AssignLiteral("&T");
+  mHeaderStrs[2].AssignLiteral("&U");
+
+  mFooterStrs[0].AssignLiteral(
+      "&PT");  // Use &P (Page Num Only) or &PT (Page Num of Page Total)
+  mFooterStrs[2].AssignLiteral("&D");
+}
+
+void nsPrintSettings::InitWithInitializer(
+    const PrintSettingsInitializer& aSettings) {
+  const double kInchesPerPoint = 1.0 / 72.0;
+
+  SetPrinterName(aSettings.mPrinter);
+  SetPrintInColor(aSettings.mPrintInColor);
+  SetResolution(aSettings.mResolution);
+  SetNumCopies(aSettings.mNumCopies);
+  SetDuplex(aSettings.mDuplex);
+  // The paper ID used by nsPrintSettings is the non-localizable identifier
+  // exposed as "id" by the paper, not the potentially localized human-friendly
+  // "name", which could change, e.g. if the user changes their system locale.
+  SetPaperId(aSettings.mPaperInfo.mId);
+
+  // Set the paper sizes to match the unit.
+  SetPaperSizeUnit(aSettings.mPaperSizeUnit);
+  double sizeUnitsPerPoint =
+      aSettings.mPaperSizeUnit == kPaperSizeInches ? 1.0 / 72.0 : 25.4 / 72.0;
+  SetPaperWidth(aSettings.mPaperInfo.mSize.width * sizeUnitsPerPoint);
+  SetPaperHeight(aSettings.mPaperInfo.mSize.height * sizeUnitsPerPoint);
+
+  // If our initializer says that we're producing portrait-mode sheets of
+  // paper, then our page format must also be portrait-mode; unless we've got
+  // a pages-per-sheet value with orthogonal pages/sheets, in which case it's
+  // reversed.
+  const bool areSheetsOfPaperPortraitMode =
+      (aSettings.mSheetOrientation == kPortraitOrientation);
+  const bool arePagesPortraitMode =
+      (areSheetsOfPaperPortraitMode != HasOrthogonalPagesPerSheet());
+  SetOrientation(arePagesPortraitMode ? kPortraitOrientation
+                                      : kLandscapeOrientation);
+
+  if (aSettings.mPaperInfo.mUnwriteableMargin) {
+    const auto& margin = aSettings.mPaperInfo.mUnwriteableMargin.value();
+    // Margins are stored internally in TWIPS, but the setters expect inches.
+    SetUnwriteableMarginTop(margin.top * kInchesPerPoint);
+    SetUnwriteableMarginRight(margin.right * kInchesPerPoint);
+    SetUnwriteableMarginBottom(margin.bottom * kInchesPerPoint);
+    SetUnwriteableMarginLeft(margin.left * kInchesPerPoint);
+  }
+
+  // Set this last because other setters may overwrite its value.
+  SetIsInitializedFromPrinter(true);
+}
+
+nsPrintSettings::nsPrintSettings(const nsPrintSettings& aPS) { *this = aPS; }
+
+nsPrintSettings::~nsPrintSettings() = default;
+
+NS_IMETHODIMP nsPrintSettings::GetPrintReversed(bool* aPrintReversed) {
+  *aPrintReversed = mPrintReversed;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetPrintReversed(bool aPrintReversed) {
+  mPrintReversed = aPrintReversed;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetPrintInColor(bool* aPrintInColor) {
+  *aPrintInColor = mPrintInColor;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetPrintInColor(bool aPrintInColor) {
+  mPrintInColor = aPrintInColor;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetOrientation(int32_t* aOrientation) {
+  *aOrientation = mOrientation;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetOrientation(int32_t aOrientation) {
+  mOrientation = aOrientation;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetResolution(int32_t* aResolution) {
+  NS_ENSURE_ARG_POINTER(aResolution);
+  *aResolution = mResolution;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetResolution(const int32_t aResolution) {
+  mResolution = aResolution;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetDuplex(int32_t* aDuplex) {
+  NS_ENSURE_ARG_POINTER(aDuplex);
+  *aDuplex = mDuplex;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetDuplex(const int32_t aDuplex) {
+  mDuplex = aDuplex;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetPrinterName(nsAString& aPrinter) {
+  aPrinter = mPrinter;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::SetPrinterName(const nsAString& aPrinter) {
+  if (!mPrinter.Equals(aPrinter)) {
+    mIsInitedFromPrinter = false;
+    mIsInitedFromPrefs = false;
+  }
+
+  mPrinter.Assign(aPrinter);
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetNumCopies(int32_t* aNumCopies) {
+  NS_ENSURE_ARG_POINTER(aNumCopies);
+  *aNumCopies = mNumCopies;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetNumCopies(int32_t aNumCopies) {
+  mNumCopies = aNumCopies;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetNumPagesPerSheet(int32_t* aNumPagesPerSheet) {
+  NS_ENSURE_ARG_POINTER(aNumPagesPerSheet);
+  *aNumPagesPerSheet = mNumPagesPerSheet;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetNumPagesPerSheet(int32_t aNumPagesPerSheet) {
+  mNumPagesPerSheet = aNumPagesPerSheet;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetOutputDestination(
+    OutputDestinationType* aDestination) {
+  *aDestination = mOutputDestination;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::SetOutputDestination(
+    OutputDestinationType aDestination) {
+  mOutputDestination = aDestination;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::SetOutputStream(nsIOutputStream* aStream) {
+  mOutputStream = aStream;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetOutputStream(nsIOutputStream** aStream) {
+  NS_IF_ADDREF(*aStream = mOutputStream.get());
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetToFileName(nsAString& aToFileName) {
+  aToFileName = mToFileName;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetToFileName(const nsAString& aToFileName) {
+  mToFileName = aToFileName;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetOutputFormat(int16_t* aOutputFormat) {
+  NS_ENSURE_ARG_POINTER(aOutputFormat);
+  *aOutputFormat = mOutputFormat;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetOutputFormat(int16_t aOutputFormat) {
+  mOutputFormat = aOutputFormat;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetPrintPageDelay(int32_t* aPrintPageDelay) {
+  *aPrintPageDelay = mPrintPageDelay;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetPrintPageDelay(int32_t aPrintPageDelay) {
+  mPrintPageDelay = aPrintPageDelay;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetIsInitializedFromPrinter(
+    bool* aIsInitializedFromPrinter) {
+  NS_ENSURE_ARG_POINTER(aIsInitializedFromPrinter);
+  *aIsInitializedFromPrinter = mIsInitedFromPrinter;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetIsInitializedFromPrinter(
+    bool aIsInitializedFromPrinter) {
+  mIsInitedFromPrinter = aIsInitializedFromPrinter;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetIsInitializedFromPrefs(
+    bool* aInitializedFromPrefs) {
+  NS_ENSURE_ARG_POINTER(aInitializedFromPrefs);
+  *aInitializedFromPrefs = mIsInitedFromPrefs;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetIsInitializedFromPrefs(
+    bool aInitializedFromPrefs) {
+  mIsInitedFromPrefs = aInitializedFromPrefs;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetMarginTop(double* aMarginTop) {
+  NS_ENSURE_ARG_POINTER(aMarginTop);
+  *aMarginTop = NS_TWIPS_TO_INCHES(mMargin.top);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetMarginTop(double aMarginTop) {
+  mMargin.top = NS_INCHES_TO_INT_TWIPS(float(aMarginTop));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetMarginLeft(double* aMarginLeft) {
+  NS_ENSURE_ARG_POINTER(aMarginLeft);
+  *aMarginLeft = NS_TWIPS_TO_INCHES(mMargin.left);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetMarginLeft(double aMarginLeft) {
+  mMargin.left = NS_INCHES_TO_INT_TWIPS(float(aMarginLeft));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetMarginBottom(double* aMarginBottom) {
+  NS_ENSURE_ARG_POINTER(aMarginBottom);
+  *aMarginBottom = NS_TWIPS_TO_INCHES(mMargin.bottom);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetMarginBottom(double aMarginBottom) {
+  mMargin.bottom = NS_INCHES_TO_INT_TWIPS(float(aMarginBottom));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetMarginRight(double* aMarginRight) {
+  NS_ENSURE_ARG_POINTER(aMarginRight);
+  *aMarginRight = NS_TWIPS_TO_INCHES(mMargin.right);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetMarginRight(double aMarginRight) {
+  mMargin.right = NS_INCHES_TO_INT_TWIPS(float(aMarginRight));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetEdgeTop(double* aEdgeTop) {
+  NS_ENSURE_ARG_POINTER(aEdgeTop);
+  *aEdgeTop = NS_TWIPS_TO_INCHES(mEdge.top);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetEdgeTop(double aEdgeTop) {
+  mEdge.top = NS_INCHES_TO_INT_TWIPS(float(aEdgeTop));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetEdgeLeft(double* aEdgeLeft) {
+  NS_ENSURE_ARG_POINTER(aEdgeLeft);
+  *aEdgeLeft = NS_TWIPS_TO_INCHES(mEdge.left);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetEdgeLeft(double aEdgeLeft) {
+  mEdge.left = NS_INCHES_TO_INT_TWIPS(float(aEdgeLeft));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetEdgeBottom(double* aEdgeBottom) {
+  NS_ENSURE_ARG_POINTER(aEdgeBottom);
+  *aEdgeBottom = NS_TWIPS_TO_INCHES(mEdge.bottom);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetEdgeBottom(double aEdgeBottom) {
+  mEdge.bottom = NS_INCHES_TO_INT_TWIPS(float(aEdgeBottom));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetEdgeRight(double* aEdgeRight) {
+  NS_ENSURE_ARG_POINTER(aEdgeRight);
+  *aEdgeRight = NS_TWIPS_TO_INCHES(mEdge.right);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetEdgeRight(double aEdgeRight) {
+  mEdge.right = NS_INCHES_TO_INT_TWIPS(float(aEdgeRight));
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetUnwriteableMarginTop(
+    double* aUnwriteableMarginTop) {
+  NS_ENSURE_ARG_POINTER(aUnwriteableMarginTop);
+  *aUnwriteableMarginTop = NS_TWIPS_TO_INCHES(mUnwriteableMargin.top);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetUnwriteableMarginTop(
+    double aUnwriteableMarginTop) {
+  if (aUnwriteableMarginTop >= 0.0) {
+    mUnwriteableMargin.top = NS_INCHES_TO_INT_TWIPS(aUnwriteableMarginTop);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetUnwriteableMarginLeft(
+    double* aUnwriteableMarginLeft) {
+  NS_ENSURE_ARG_POINTER(aUnwriteableMarginLeft);
+  *aUnwriteableMarginLeft = NS_TWIPS_TO_INCHES(mUnwriteableMargin.left);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetUnwriteableMarginLeft(
+    double aUnwriteableMarginLeft) {
+  if (aUnwriteableMarginLeft >= 0.0) {
+    mUnwriteableMargin.left = NS_INCHES_TO_INT_TWIPS(aUnwriteableMarginLeft);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetUnwriteableMarginBottom(
+    double* aUnwriteableMarginBottom) {
+  NS_ENSURE_ARG_POINTER(aUnwriteableMarginBottom);
+  *aUnwriteableMarginBottom = NS_TWIPS_TO_INCHES(mUnwriteableMargin.bottom);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetUnwriteableMarginBottom(
+    double aUnwriteableMarginBottom) {
+  if (aUnwriteableMarginBottom >= 0.0) {
+    mUnwriteableMargin.bottom =
+        NS_INCHES_TO_INT_TWIPS(aUnwriteableMarginBottom);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetUnwriteableMarginRight(
+    double* aUnwriteableMarginRight) {
+  NS_ENSURE_ARG_POINTER(aUnwriteableMarginRight);
+  *aUnwriteableMarginRight = NS_TWIPS_TO_INCHES(mUnwriteableMargin.right);
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetUnwriteableMarginRight(
+    double aUnwriteableMarginRight) {
+  if (aUnwriteableMarginRight >= 0.0) {
+    mUnwriteableMargin.right = NS_INCHES_TO_INT_TWIPS(aUnwriteableMarginRight);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetScaling(double* aScaling) {
+  NS_ENSURE_ARG_POINTER(aScaling);
+  *aScaling = mScaling;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::SetScaling(double aScaling) {
+  mScaling = aScaling;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetPrintBGColors(bool* aPrintBGColors) {
+  NS_ENSURE_ARG_POINTER(aPrintBGColors);
+  *aPrintBGColors = mPrintBGColors;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetPrintBGColors(bool aPrintBGColors) {
+  mPrintBGColors = aPrintBGColors;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetPrintBGImages(bool* aPrintBGImages) {
+  NS_ENSURE_ARG_POINTER(aPrintBGImages);
+  *aPrintBGImages = mPrintBGImages;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetPrintBGImages(bool aPrintBGImages) {
+  mPrintBGImages = aPrintBGImages;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetTitle(nsAString& aTitle) {
+  aTitle = mTitle;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetTitle(const nsAString& aTitle) {
+  mTitle = aTitle;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetDocURL(nsAString& aDocURL) {
+  aDocURL = mURL;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetDocURL(const nsAString& aDocURL) {
+  mURL = aDocURL;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetHeaderStrLeft(nsAString& aTitle) {
+  aTitle = mHeaderStrs[0];
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetHeaderStrLeft(const nsAString& aTitle) {
+  mHeaderStrs[0] = aTitle;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetHeaderStrCenter(nsAString& aTitle) {
+  aTitle = mHeaderStrs[1];
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetHeaderStrCenter(const nsAString& aTitle) {
+  mHeaderStrs[1] = aTitle;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetHeaderStrRight(nsAString& aTitle) {
+  aTitle = mHeaderStrs[2];
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetHeaderStrRight(const nsAString& aTitle) {
+  mHeaderStrs[2] = aTitle;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetFooterStrLeft(nsAString& aTitle) {
+  aTitle = mFooterStrs[0];
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetFooterStrLeft(const nsAString& aTitle) {
+  mFooterStrs[0] = aTitle;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetFooterStrCenter(nsAString& aTitle) {
+  aTitle = mFooterStrs[1];
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetFooterStrCenter(const nsAString& aTitle) {
+  mFooterStrs[1] = aTitle;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetFooterStrRight(nsAString& aTitle) {
+  aTitle = mFooterStrs[2];
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetFooterStrRight(const nsAString& aTitle) {
+  mFooterStrs[2] = aTitle;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetPrintSilent(bool* aPrintSilent) {
+  NS_ENSURE_ARG_POINTER(aPrintSilent);
+  *aPrintSilent = mPrintSilent;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetPrintSilent(bool aPrintSilent) {
+  mPrintSilent = aPrintSilent;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetShrinkToFit(bool* aShrinkToFit) {
+  NS_ENSURE_ARG_POINTER(aShrinkToFit);
+  *aShrinkToFit = mShrinkToFit;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetShrinkToFit(bool aShrinkToFit) {
+  mShrinkToFit = aShrinkToFit;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetShowMarginGuides(bool* aShowMarginGuides) {
+  *aShowMarginGuides = mShowMarginGuides;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::SetShowMarginGuides(bool aShowMarginGuides) {
+  mShowMarginGuides = aShowMarginGuides;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetHonorPageRuleMargins(bool* aResult) {
+  *aResult = mHonorPageRuleMargins;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::SetHonorPageRuleMargins(bool aHonor) {
+  mHonorPageRuleMargins = aHonor;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetUsePageRuleSizeAsPaperSize(bool* aResult) {
+  *aResult = mUsePageRuleSizeAsPaperSize;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::SetUsePageRuleSizeAsPaperSize(bool aHonor) {
+  mUsePageRuleSizeAsPaperSize = aHonor;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetIgnoreUnwriteableMargins(bool* aResult) {
+  *aResult = mIgnoreUnwriteableMargins;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::SetIgnoreUnwriteableMargins(bool aIgnore) {
+  mIgnoreUnwriteableMargins = aIgnore;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetPrintSelectionOnly(bool* aResult) {
+  *aResult = mPrintSelectionOnly;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::SetPrintSelectionOnly(bool aSelectionOnly) {
+  mPrintSelectionOnly = aSelectionOnly;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetPaperId(nsAString& aPaperId) {
+  aPaperId = mPaperId;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetPaperId(const nsAString& aPaperId) {
+  mPaperId = aPaperId;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetPaperWidth(double* aPaperWidth) {
+  NS_ENSURE_ARG_POINTER(aPaperWidth);
+  *aPaperWidth = mPaperWidth;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetPaperWidth(double aPaperWidth) {
+  mPaperWidth = aPaperWidth;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetPaperHeight(double* aPaperHeight) {
+  NS_ENSURE_ARG_POINTER(aPaperHeight);
+  *aPaperHeight = mPaperHeight;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetPaperHeight(double aPaperHeight) {
+  mPaperHeight = aPaperHeight;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettings::GetPaperSizeUnit(int16_t* aPaperSizeUnit) {
+  NS_ENSURE_ARG_POINTER(aPaperSizeUnit);
+  *aPaperSizeUnit = mPaperSizeUnit;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettings::SetPaperSizeUnit(int16_t aPaperSizeUnit) {
+  mPaperSizeUnit = aPaperSizeUnit;
+  return NS_OK;
+}
+
+/** ---------------------------------------------------
+ *  See documentation in nsPrintSettingsService.h
+ *	@update 6/21/00 dwc
+ *	@update 1/12/01 rods
+ */
+NS_IMETHODIMP
+nsPrintSettings::SetMarginInTwips(nsIntMargin& aMargin) {
+  mMargin = aMargin;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettings::SetEdgeInTwips(nsIntMargin& aEdge) {
+  mEdge = aEdge;
+  return NS_OK;
+}
+
+// NOTE: Any subclass implementation of this function should make sure
+// to check for negative margin values in aUnwriteableMargin (which
+// would indicate that we should use the system default unwriteable margin.)
+NS_IMETHODIMP
+nsPrintSettings::SetUnwriteableMarginInTwips(nsIntMargin& aUnwriteableMargin) {
+  if (aUnwriteableMargin.top >= 0) {
+    mUnwriteableMargin.top = aUnwriteableMargin.top;
+  }
+  if (aUnwriteableMargin.left >= 0) {
+    mUnwriteableMargin.left = aUnwriteableMargin.left;
+  }
+  if (aUnwriteableMargin.bottom >= 0) {
+    mUnwriteableMargin.bottom = aUnwriteableMargin.bottom;
+  }
+  if (aUnwriteableMargin.right >= 0) {
+    mUnwriteableMargin.right = aUnwriteableMargin.right;
+  }
+  return NS_OK;
+}
+
+nsIntMargin nsPrintSettings::GetMarginInTwips() { return mMargin; }
+
+nsIntMargin nsPrintSettings::GetEdgeInTwips() { return mEdge; }
+
+nsIntMargin nsPrintSettings::GetUnwriteableMarginInTwips() {
+  return mUnwriteableMargin;
+}
+
+/** ---------------------------------------------------
+ *  See documentation in nsPrintSettingsService.h
+ */
+NS_IMETHODIMP
+nsPrintSettings::GetEffectivePageSize(double* aWidth, double* aHeight) {
+  if (mPaperSizeUnit == kPaperSizeInches) {
+    *aWidth = NS_INCHES_TO_TWIPS(float(mPaperWidth));
+    *aHeight = NS_INCHES_TO_TWIPS(float(mPaperHeight));
+  } else {
+    MOZ_ASSERT(mPaperSizeUnit == kPaperSizeMillimeters,
+               "unexpected paper size unit");
+    *aWidth = NS_MILLIMETERS_TO_TWIPS(float(mPaperWidth));
+    *aHeight = NS_MILLIMETERS_TO_TWIPS(float(mPaperHeight));
+  }
+  if (kLandscapeOrientation == mOrientation) {
+    double temp = *aWidth;
+    *aWidth = *aHeight;
+    *aHeight = temp;
+  }
+  return NS_OK;
+}
+
+bool nsPrintSettings::HasOrthogonalPagesPerSheet() {
+  return mNumPagesPerSheet == 2 || mNumPagesPerSheet == 6;
+}
+
+void nsPrintSettings::GetEffectiveSheetSize(double* aWidth, double* aHeight) {
+  mozilla::DebugOnly<nsresult> rv = GetEffectivePageSize(aWidth, aHeight);
+
+  // Our GetEffectivePageSize impls only return NS_OK, so this should hold:
+  MOZ_ASSERT(NS_SUCCEEDED(rv), "Uh oh, GetEffectivePageSize failed");
+
+  if (HasOrthogonalPagesPerSheet()) {
+    std::swap(*aWidth, *aHeight);
+  }
+}
+
+int32_t nsPrintSettings::GetSheetOrientation() {
+  if (HasOrthogonalPagesPerSheet()) {
+    // Sheet orientation is rotated with respect to the page orientation.
+    return kLandscapeOrientation == mOrientation ? kPortraitOrientation
+                                                 : kLandscapeOrientation;
+  }
+
+  // Sheet orientation is the same as the page orientation.
+  return mOrientation;
+}
+
+NS_IMETHODIMP
+nsPrintSettings::SetPageRanges(const nsTArray<int32_t>& aPages) {
+  // Needs to be a set of (start, end) pairs.
+  if (aPages.Length() % 2 != 0) {
+    return NS_ERROR_FAILURE;
+  }
+  mPageRanges = aPages.Clone();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettings::GetPageRanges(nsTArray<int32_t>& aPages) {
+  aPages = mPageRanges.Clone();
+  return NS_OK;
+}
+
+bool nsIPrintSettings::IsPageSkipped(int32_t aPageNum,
+                                     const nsTArray<int32_t>& aRanges) {
+  MOZ_RELEASE_ASSERT(aRanges.Length() % 2 == 0);
+  if (aRanges.IsEmpty()) {
+    return false;
+  }
+  for (size_t i = 0; i < aRanges.Length(); i += 2) {
+    if (aRanges[i] <= aPageNum && aPageNum <= aRanges[i + 1]) {
+      // The page is included in this piece of the custom range,
+      // so it's not skipped.
+      return false;
+    }
+  }
+  return true;
+}
+
+nsresult nsPrintSettings::_Clone(nsIPrintSettings** _retval) {
+  RefPtr<nsPrintSettings> printSettings = new nsPrintSettings(*this);
+  printSettings.forget(_retval);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettings::Clone(nsIPrintSettings** _retval) {
+  NS_ENSURE_ARG_POINTER(_retval);
+  return _Clone(_retval);
+}
+
+nsresult nsPrintSettings::_Assign(nsIPrintSettings* aPS) {
+  nsPrintSettings* ps = static_cast<nsPrintSettings*>(aPS);
+  *this = *ps;
+  return NS_OK;
+}
+
+nsresult nsPrintSettings::EquivalentTo(nsIPrintSettings* aPrintSettings,
+                                       bool* _retval) {
+  MOZ_ASSERT(aPrintSettings);
+  *_retval = false;
+  auto* other = static_cast<nsPrintSettings*>(aPrintSettings);
+  if (GetMarginInTwips() != aPrintSettings->GetMarginInTwips()) {
+    return NS_OK;
+  }
+  if (GetEdgeInTwips() != aPrintSettings->GetEdgeInTwips()) {
+    return NS_OK;
+  }
+  if (GetUnwriteableMarginInTwips() !=
+      aPrintSettings->GetUnwriteableMarginInTwips()) {
+    return NS_OK;
+  }
+  nsTArray<int32_t> ourPageRanges, otherPageRanges;
+  if (NS_FAILED(GetPageRanges(ourPageRanges)) ||
+      NS_FAILED(aPrintSettings->GetPageRanges(otherPageRanges)) ||
+      ourPageRanges != otherPageRanges) {
+    return NS_OK;
+  }
+  double ourScaling, otherScaling;
+  if (NS_FAILED(GetScaling(&ourScaling)) ||
+      NS_FAILED(aPrintSettings->GetScaling(&otherScaling)) ||
+      ourScaling != otherScaling) {
+    return NS_OK;
+  }
+  if (GetPrintBGColors() != aPrintSettings->GetPrintBGColors()) {
+    return NS_OK;
+  }
+  if (GetPrintBGImages() != aPrintSettings->GetPrintBGImages()) {
+    return NS_OK;
+  }
+  if (GetPrintSelectionOnly() != aPrintSettings->GetPrintSelectionOnly()) {
+    return NS_OK;
+  }
+  if (GetShrinkToFit() != aPrintSettings->GetShrinkToFit()) {
+    return NS_OK;
+  }
+  if (GetShowMarginGuides() != aPrintSettings->GetShowMarginGuides()) {
+    return NS_OK;
+  }
+  if (GetHonorPageRuleMargins() != aPrintSettings->GetHonorPageRuleMargins()) {
+    return NS_OK;
+  }
+  if (GetUsePageRuleSizeAsPaperSize() !=
+      aPrintSettings->GetUsePageRuleSizeAsPaperSize()) {
+    return NS_OK;
+  }
+  if (GetIgnoreUnwriteableMargins() !=
+      aPrintSettings->GetIgnoreUnwriteableMargins()) {
+    return NS_OK;
+  }
+  nsAutoString ourTitle, otherTitle;
+  if (NS_FAILED(GetTitle(ourTitle)) ||
+      NS_FAILED(aPrintSettings->GetTitle(otherTitle)) ||
+      ourTitle != otherTitle) {
+    return NS_OK;
+  }
+  nsAutoString ourUrl, otherUrl;
+  if (NS_FAILED(GetDocURL(ourUrl)) ||
+      NS_FAILED(aPrintSettings->GetDocURL(otherUrl)) || ourUrl != otherUrl) {
+    return NS_OK;
+  }
+  if (!mozilla::ArrayEqual(mHeaderStrs, other->mHeaderStrs) ||
+      !mozilla::ArrayEqual(mFooterStrs, other->mFooterStrs)) {
+    return NS_OK;
+  }
+  nsAutoString ourPaperId, otherPaperId;
+  if (NS_FAILED(GetPaperId(ourPaperId)) ||
+      NS_FAILED(aPrintSettings->GetPaperId(otherPaperId)) ||
+      ourPaperId != otherPaperId) {
+    return NS_OK;
+  }
+  double ourWidth, ourHeight, otherWidth, otherHeight;
+  if (NS_FAILED(GetEffectivePageSize(&ourWidth, &ourHeight)) ||
+      NS_FAILED(other->GetEffectivePageSize(&otherWidth, &otherHeight)) ||
+      std::abs(ourWidth - otherWidth) >= 1 ||
+      std::abs(ourHeight - otherHeight) >= 1) {
+    return NS_OK;
+  }
+  int32_t ourOrientation, otherOrientation;
+  if (NS_FAILED(GetOrientation(&ourOrientation)) ||
+      NS_FAILED(aPrintSettings->GetOrientation(&otherOrientation)) ||
+      ourOrientation != otherOrientation) {
+    return NS_OK;
+  }
+  int32_t ourResolution, otherResolution;
+  if (NS_FAILED(GetResolution(&ourResolution)) ||
+      NS_FAILED(aPrintSettings->GetResolution(&otherResolution)) ||
+      ourResolution != otherResolution) {
+    return NS_OK;
+  }
+  int32_t ourNumPagesPerSheet, otherNumPagesPerSheet;
+  if (NS_FAILED(GetNumPagesPerSheet(&ourNumPagesPerSheet)) ||
+      NS_FAILED(aPrintSettings->GetNumPagesPerSheet(&otherNumPagesPerSheet)) ||
+      ourNumPagesPerSheet != otherNumPagesPerSheet) {
+    return NS_OK;
+  }
+
+  *_retval = true;
+  return NS_OK;
+}
+
+mozilla::PrintSettingsInitializer nsPrintSettings::GetSettingsInitializer() {
+  mozilla::PrintSettingsInitializer settingsInitializer;
+  settingsInitializer.mPrinter.Assign(mPrinter);
+  settingsInitializer.mPaperInfo.mId = mPaperId;
+
+  double pointsPerSizeUnit =
+      mPaperSizeUnit == kPaperSizeInches ? 72.0 : 72.0 / 25.4;
+  settingsInitializer.mPaperInfo.mSize = {mPaperWidth * pointsPerSizeUnit,
+                                          mPaperHeight * pointsPerSizeUnit};
+
+  // Unwritable margins are stored in TWIPS here and points in PaperInfo.
+  settingsInitializer.mPaperInfo.mUnwriteableMargin =
+      Some(mozilla::gfx::MarginDouble(
+          mUnwriteableMargin.top / 20.0, mUnwriteableMargin.right / 20.0,
+          mUnwriteableMargin.bottom / 20.0, mUnwriteableMargin.left / 20.0));
+
+  settingsInitializer.mPrintInColor = mPrintInColor;
+  settingsInitializer.mResolution = mResolution;
+  settingsInitializer.mSheetOrientation = GetSheetOrientation();
+  settingsInitializer.mNumCopies = mNumCopies;
+  settingsInitializer.mDuplex = mDuplex;
+  RefPtr<nsIPrintSettings> settingsToInitialize;
+  MOZ_ALWAYS_SUCCEEDS(Clone(getter_AddRefs(settingsToInitialize)));
+  settingsInitializer.mPrintSettings =
+      new nsMainThreadPtrHolder<nsPrintSettings>(
+          "PrintSettingsInitializer::mPrintSettings",
+          settingsToInitialize.forget().downcast<nsPrintSettings>());
+  return settingsInitializer;
+}
+
+NS_IMETHODIMP
+nsPrintSettings::Assign(nsIPrintSettings* aPS) {
+  NS_ENSURE_ARG(aPS);
+  return _Assign(aPS);
+}
+
+//-------------------------------------------
+nsPrintSettings& nsPrintSettings::operator=(const nsPrintSettings& rhs) {
+  if (this == &rhs) {
+    return *this;
+  }
+
+  mPageRanges = rhs.mPageRanges.Clone();
+  mMargin = rhs.mMargin;
+  mEdge = rhs.mEdge;
+  mUnwriteableMargin = rhs.mUnwriteableMargin;
+  mScaling = rhs.mScaling;
+  mPrintBGColors = rhs.mPrintBGColors;
+  mPrintBGImages = rhs.mPrintBGImages;
+  mTitle = rhs.mTitle;
+  mURL = rhs.mURL;
+  mPrintSilent = rhs.mPrintSilent;
+  mShrinkToFit = rhs.mShrinkToFit;
+  mShowMarginGuides = rhs.mShowMarginGuides;
+  mHonorPageRuleMargins = rhs.mHonorPageRuleMargins;
+  mUsePageRuleSizeAsPaperSize = rhs.mUsePageRuleSizeAsPaperSize;
+  mIgnoreUnwriteableMargins = rhs.mIgnoreUnwriteableMargins;
+  mPrintSelectionOnly = rhs.mPrintSelectionOnly;
+  mPaperId = rhs.mPaperId;
+  mPaperWidth = rhs.mPaperWidth;
+  mPaperHeight = rhs.mPaperHeight;
+  mPaperSizeUnit = rhs.mPaperSizeUnit;
+  mPrintReversed = rhs.mPrintReversed;
+  mPrintInColor = rhs.mPrintInColor;
+  mOrientation = rhs.mOrientation;
+  mResolution = rhs.mResolution;
+  mDuplex = rhs.mDuplex;
+  mNumCopies = rhs.mNumCopies;
+  mNumPagesPerSheet = rhs.mNumPagesPerSheet;
+  mPrinter = rhs.mPrinter;
+  mOutputDestination = rhs.mOutputDestination;
+  mOutputStream = rhs.mOutputStream;
+  mToFileName = rhs.mToFileName;
+  mOutputFormat = rhs.mOutputFormat;
+  mIsInitedFromPrinter = rhs.mIsInitedFromPrinter;
+  mIsInitedFromPrefs = rhs.mIsInitedFromPrefs;
+  mPrintPageDelay = rhs.mPrintPageDelay;
+
+  for (int32_t i = 0; i < NUM_HEAD_FOOT; i++) {
+    mHeaderStrs[i] = rhs.mHeaderStrs[i];
+    mFooterStrs[i] = rhs.mFooterStrs[i];
+  }
+
+  return *this;
+}
+
+void nsPrintSettings::SetDefaultFileName() {
+  nsAutoString filename;
+  nsresult rv = GetToFileName(filename);
+  if (NS_FAILED(rv) || filename.IsEmpty()) {
+    const char* path = PR_GetEnv("PWD");
+    if (!path) {
+      path = PR_GetEnv("HOME");
+    }
+
+    if (path) {
+      CopyUTF8toUTF16(mozilla::MakeStringSpan(path), filename);
+      filename.AppendLiteral("/mozilla.pdf");
+    } else {
+      filename.AssignLiteral("mozilla.pdf");
+    }
+
+    SetToFileName(filename);
+  }
+}
diff --git a/widget/nsPrintSettingsImpl.h b/widget/nsPrintSettingsImpl.h
new file mode 100644
index 0000000000..f090cc5841
--- /dev/null
+++ b/widget/nsPrintSettingsImpl.h
@@ -0,0 +1,134 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrintSettingsImpl_h__
+#define nsPrintSettingsImpl_h__
+
+#include "nsIPrintSettings.h"
+#include "nsIWeakReferenceUtils.h"
+#include "nsMargin.h"
+#include "nsPaper.h"
+#include "nsProxyRelease.h"
+#include "nsString.h"
+
+#define NUM_HEAD_FOOT 3
+
+//*****************************************************************************
+//***    nsPrintSettings
+//*****************************************************************************
+
+class nsPrintSettings;
+
+namespace mozilla {
+
+/**
+ * A struct that can be used off the main thread to collect printer-specific
+ * info that can be used to initialized a default nsIPrintSettings object.
+ */
+struct PrintSettingsInitializer {
+  nsString mPrinter;
+  PaperInfo mPaperInfo;
+  int16_t mPaperSizeUnit = nsIPrintSettings::kPaperSizeInches;
+  // If we fail to obtain printer capabilities, being given the option to print
+  // in color to your monochrome printer is a lot less annoying than not being
+  // given the option to print in color to your color printer.
+  bool mPrintInColor = true;
+  int mResolution = 0;
+  int mSheetOrientation = nsIPrintSettings::kPortraitOrientation;
+  int mNumCopies = 1;
+  int mDuplex = nsIPrintSettings::kDuplexNone;
+
+  // This is to hold a reference to a newly cloned settings object that will
+  // then be initialized by the other values in the initializer that may have
+  // been changed on a background thread.
+  nsMainThreadPtrHandle<nsPrintSettings> mPrintSettings;
+
+#ifdef XP_WIN
+  CopyableTArray<uint8_t> mDevmodeWStorage;
+#endif
+};
+
+}  // namespace mozilla
+
+class nsPrintSettings : public nsIPrintSettings {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIPRINTSETTINGS
+  using PrintSettingsInitializer = mozilla::PrintSettingsInitializer;
+
+  nsPrintSettings();
+  nsPrintSettings(const nsPrintSettings& aPS);
+
+  /**
+   * Initialize relevant members from the PrintSettingsInitializer.
+   * This is specifically not a constructor so that we can ensure that the
+   * relevant setters are dynamically dispatched to derived classes.
+   */
+  virtual void InitWithInitializer(const PrintSettingsInitializer& aSettings);
+
+  nsPrintSettings& operator=(const nsPrintSettings& rhs);
+
+  // Sets a default file name for the print settings.
+  void SetDefaultFileName();
+
+ protected:
+  virtual ~nsPrintSettings();
+
+  // May be implemented by the platform-specific derived class
+  virtual nsresult _Clone(nsIPrintSettings** _retval);
+  virtual nsresult _Assign(nsIPrintSettings* aPS);
+
+  // Members
+  nsWeakPtr mSession;  // Should never be touched by Clone or Assign
+
+  // mMargin, mEdge, and mUnwriteableMargin are stored in twips
+  nsIntMargin mMargin;
+  nsIntMargin mEdge;
+  nsIntMargin mUnwriteableMargin;
+
+  nsTArray<int32_t> mPageRanges;
+
+  double mScaling = 1.0;
+  bool mPrintBGColors = false;
+  bool mPrintBGImages = false;
+
+  bool mPrintSilent = false;
+  bool mShrinkToFit = true;
+  bool mShowMarginGuides = false;
+  bool mHonorPageRuleMargins = true;
+  bool mUsePageRuleSizeAsPaperSize = false;
+  bool mIgnoreUnwriteableMargins = false;
+  bool mPrintSelectionOnly = false;
+
+  int32_t mPrintPageDelay = 50;  // XXX Do we really want this?
+
+  nsString mTitle;
+  nsString mURL;
+  nsString mHeaderStrs[NUM_HEAD_FOOT];
+  nsString mFooterStrs[NUM_HEAD_FOOT];
+
+  nsString mPaperId;
+  double mPaperWidth = 8.5;
+  double mPaperHeight = 11.0;
+  int16_t mPaperSizeUnit = kPaperSizeInches;
+
+  bool mPrintReversed = false;
+  bool mPrintInColor = true;
+  int32_t mOrientation = kPortraitOrientation;
+  int32_t mResolution = 0;
+  int32_t mDuplex = kDuplexNone;
+  int32_t mNumCopies = 1;
+  int32_t mNumPagesPerSheet = 1;
+  int16_t mOutputFormat = kOutputFormatNative;
+  OutputDestinationType mOutputDestination = kOutputDestinationPrinter;
+  nsString mPrinter;
+  nsString mToFileName;
+  nsCOMPtr<nsIOutputStream> mOutputStream;
+  bool mIsInitedFromPrinter = false;
+  bool mIsInitedFromPrefs = false;
+};
+
+#endif /* nsPrintSettings_h__ */
diff --git a/widget/nsPrintSettingsService.cpp b/widget/nsPrintSettingsService.cpp
new file mode 100644
index 0000000000..5f2dcd7c0a
--- /dev/null
+++ b/widget/nsPrintSettingsService.cpp
@@ -0,0 +1,1090 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrintSettingsService.h"
+
+#include "mozilla/embedding/PPrintingTypes.h"
+#include "mozilla/layout/RemotePrintJobChild.h"
+#include "mozilla/RefPtr.h"
+#include "nsCoord.h"
+#include "nsIPrinterList.h"
+#include "nsReadableUtils.h"
+#include "nsPrintSettingsImpl.h"
+#include "nsServiceManagerUtils.h"
+#include "nsSize.h"
+
+#include "nsArray.h"
+#include "nsXPCOM.h"
+#include "nsXULAppAPI.h"
+
+#include "nsIStringEnumerator.h"
+#include "stdlib.h"
+#include "mozilla/StaticPrefs_print.h"
+#include "mozilla/Preferences.h"
+#include "nsPrintfCString.h"
+
+using namespace mozilla;
+using namespace mozilla::embedding;
+
+typedef mozilla::layout::RemotePrintJobChild RemotePrintJobChild;
+
+NS_IMPL_ISUPPORTS(nsPrintSettingsService, nsIPrintSettingsService)
+
+// Pref Constants
+static const char kMarginTop[] = "print_margin_top";
+static const char kMarginLeft[] = "print_margin_left";
+static const char kMarginBottom[] = "print_margin_bottom";
+static const char kMarginRight[] = "print_margin_right";
+static const char kEdgeTop[] = "print_edge_top";
+static const char kEdgeLeft[] = "print_edge_left";
+static const char kEdgeBottom[] = "print_edge_bottom";
+static const char kEdgeRight[] = "print_edge_right";
+
+static const char kIgnoreUnwriteableMargins[] =
+    "print_ignore_unwriteable_margins";
+
+static const char kUnwriteableMarginTopTwips[] =
+    "print_unwriteable_margin_top_twips";
+static const char kUnwriteableMarginLeftTwips[] =
+    "print_unwriteable_margin_left_twips";
+static const char kUnwriteableMarginBottomTwips[] =
+    "print_unwriteable_margin_bottom_twips";
+static const char kUnwriteableMarginRightTwips[] =
+    "print_unwriteable_margin_right_twips";
+
+// These are legacy versions of the above UnwriteableMargin prefs. The new ones,
+// which are in twips, were introduced to more accurately record the values.
+static const char kUnwriteableMarginTop[] = "print_unwriteable_margin_top";
+static const char kUnwriteableMarginLeft[] = "print_unwriteable_margin_left";
+static const char kUnwriteableMarginBottom[] =
+    "print_unwriteable_margin_bottom";
+static const char kUnwriteableMarginRight[] = "print_unwriteable_margin_right";
+
+// Prefs for Print Options
+static const char kPrintHeaderStrLeft[] = "print_headerleft";
+static const char kPrintHeaderStrCenter[] = "print_headercenter";
+static const char kPrintHeaderStrRight[] = "print_headerright";
+static const char kPrintFooterStrLeft[] = "print_footerleft";
+static const char kPrintFooterStrCenter[] = "print_footercenter";
+static const char kPrintFooterStrRight[] = "print_footerright";
+
+// Additional Prefs
+static const char kPrintReversed[] = "print_reversed";
+static const char kPrintInColor[] = "print_in_color";
+static const char kPrintPaperId[] = "print_paper_id";
+static const char kPrintPaperSizeUnit[] = "print_paper_size_unit";
+static const char kPrintPaperWidth[] = "print_paper_width";
+static const char kPrintPaperHeight[] = "print_paper_height";
+static const char kPrintOrientation[] = "print_orientation";
+static const char kPrinterName[] = "print_printer";
+static const char kPrintToFile[] = "print_to_file";
+static const char kPrintToFileName[] = "print_to_filename";
+static const char kPrintPageDelay[] = "print_page_delay";
+static const char kPrintBGColors[] = "print_bgcolor";
+static const char kPrintBGImages[] = "print_bgimages";
+static const char kPrintShrinkToFit[] = "print_shrink_to_fit";
+static const char kPrintScaling[] = "print_scaling";
+static const char kPrintDuplex[] = "print_duplex";
+
+static const char kJustLeft[] = "left";
+static const char kJustCenter[] = "center";
+static const char kJustRight[] = "right";
+
+#define NS_PRINTER_LIST_CONTRACTID "@mozilla.org/gfx/printerlist;1"
+
+nsresult nsPrintSettingsService::Init() { return NS_OK; }
+
+NS_IMETHODIMP
+nsPrintSettingsService::SerializeToPrintData(nsIPrintSettings* aSettings,
+                                             PrintData* data) {
+  aSettings->GetPageRanges(data->pageRanges());
+
+  aSettings->GetEdgeTop(&data->edgeTop());
+  aSettings->GetEdgeLeft(&data->edgeLeft());
+  aSettings->GetEdgeBottom(&data->edgeBottom());
+  aSettings->GetEdgeRight(&data->edgeRight());
+
+  aSettings->GetMarginTop(&data->marginTop());
+  aSettings->GetMarginLeft(&data->marginLeft());
+  aSettings->GetMarginBottom(&data->marginBottom());
+  aSettings->GetMarginRight(&data->marginRight());
+  aSettings->GetUnwriteableMarginTop(&data->unwriteableMarginTop());
+  aSettings->GetUnwriteableMarginLeft(&data->unwriteableMarginLeft());
+  aSettings->GetUnwriteableMarginBottom(&data->unwriteableMarginBottom());
+  aSettings->GetUnwriteableMarginRight(&data->unwriteableMarginRight());
+
+  aSettings->GetScaling(&data->scaling());
+
+  data->printBGColors() = aSettings->GetPrintBGColors();
+  data->printBGImages() = aSettings->GetPrintBGImages();
+
+  data->ignoreUnwriteableMargins() = aSettings->GetIgnoreUnwriteableMargins();
+  data->honorPageRuleMargins() = aSettings->GetHonorPageRuleMargins();
+  data->usePageRuleSizeAsPaperSize() =
+      aSettings->GetUsePageRuleSizeAsPaperSize();
+  data->showMarginGuides() = aSettings->GetShowMarginGuides();
+  data->printSelectionOnly() = aSettings->GetPrintSelectionOnly();
+
+  aSettings->GetTitle(data->title());
+  aSettings->GetDocURL(data->docURL());
+
+  aSettings->GetHeaderStrLeft(data->headerStrLeft());
+  aSettings->GetHeaderStrCenter(data->headerStrCenter());
+  aSettings->GetHeaderStrRight(data->headerStrRight());
+
+  aSettings->GetFooterStrLeft(data->footerStrLeft());
+  aSettings->GetFooterStrCenter(data->footerStrCenter());
+  aSettings->GetFooterStrRight(data->footerStrRight());
+
+  aSettings->GetPrintSilent(&data->printSilent());
+  aSettings->GetShrinkToFit(&data->shrinkToFit());
+
+  aSettings->GetPaperId(data->paperId());
+  aSettings->GetPaperWidth(&data->paperWidth());
+  aSettings->GetPaperHeight(&data->paperHeight());
+  aSettings->GetPaperSizeUnit(&data->paperSizeUnit());
+
+  aSettings->GetPrintReversed(&data->printReversed());
+  aSettings->GetPrintInColor(&data->printInColor());
+  aSettings->GetOrientation(&data->orientation());
+
+  aSettings->GetNumCopies(&data->numCopies());
+  aSettings->GetNumPagesPerSheet(&data->numPagesPerSheet());
+
+  data->outputDestination() = aSettings->GetOutputDestination();
+
+  data->outputFormat() = aSettings->GetOutputFormat();
+  data->printPageDelay() = aSettings->GetPrintPageDelay();
+  data->resolution() = aSettings->GetResolution();
+  data->duplex() = aSettings->GetDuplex();
+
+  aSettings->GetIsInitializedFromPrinter(&data->isInitializedFromPrinter());
+  aSettings->GetIsInitializedFromPrefs(&data->isInitializedFromPrefs());
+
+  // Initialize the platform-specific values that don't
+  // default-initialize, so that we don't send uninitialized data over
+  // IPC (which leads to valgrind warnings, and, for bools, fatal
+  // assertions).
+  // data->driverName() default-initializes
+  // data->deviceName() default-initializes
+  // data->GTKPrintSettings() default-initializes
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsService::DeserializeToPrintSettings(const PrintData& data,
+                                                   nsIPrintSettings* settings) {
+  settings->SetPageRanges(data.pageRanges());
+
+  settings->SetEdgeTop(data.edgeTop());
+  settings->SetEdgeLeft(data.edgeLeft());
+  settings->SetEdgeBottom(data.edgeBottom());
+  settings->SetEdgeRight(data.edgeRight());
+
+  settings->SetMarginTop(data.marginTop());
+  settings->SetMarginLeft(data.marginLeft());
+  settings->SetMarginBottom(data.marginBottom());
+  settings->SetMarginRight(data.marginRight());
+  settings->SetUnwriteableMarginTop(data.unwriteableMarginTop());
+  settings->SetUnwriteableMarginLeft(data.unwriteableMarginLeft());
+  settings->SetUnwriteableMarginBottom(data.unwriteableMarginBottom());
+  settings->SetUnwriteableMarginRight(data.unwriteableMarginRight());
+
+  settings->SetScaling(data.scaling());
+
+  settings->SetPrintBGColors(data.printBGColors());
+  settings->SetPrintBGImages(data.printBGImages());
+  settings->SetHonorPageRuleMargins(data.honorPageRuleMargins());
+  settings->SetUsePageRuleSizeAsPaperSize(data.usePageRuleSizeAsPaperSize());
+  settings->SetIgnoreUnwriteableMargins(data.ignoreUnwriteableMargins());
+  settings->SetShowMarginGuides(data.showMarginGuides());
+  settings->SetPrintSelectionOnly(data.printSelectionOnly());
+
+  settings->SetTitle(data.title());
+  settings->SetDocURL(data.docURL());
+
+  // Header strings...
+  settings->SetHeaderStrLeft(data.headerStrLeft());
+  settings->SetHeaderStrCenter(data.headerStrCenter());
+  settings->SetHeaderStrRight(data.headerStrRight());
+
+  // Footer strings...
+  settings->SetFooterStrLeft(data.footerStrLeft());
+  settings->SetFooterStrCenter(data.footerStrCenter());
+  settings->SetFooterStrRight(data.footerStrRight());
+
+  settings->SetPrintSilent(data.printSilent());
+  settings->SetShrinkToFit(data.shrinkToFit());
+
+  settings->SetPaperId(data.paperId());
+
+  settings->SetPaperWidth(data.paperWidth());
+  settings->SetPaperHeight(data.paperHeight());
+  settings->SetPaperSizeUnit(data.paperSizeUnit());
+
+  settings->SetPrintReversed(data.printReversed());
+  settings->SetPrintInColor(data.printInColor());
+  settings->SetOrientation(data.orientation());
+
+  settings->SetNumCopies(data.numCopies());
+  settings->SetNumPagesPerSheet(data.numPagesPerSheet());
+
+  settings->SetOutputDestination(
+      nsIPrintSettings::OutputDestinationType(data.outputDestination()));
+  // Output stream intentionally unset, child processes shouldn't care about it.
+
+  settings->SetOutputFormat(data.outputFormat());
+  settings->SetPrintPageDelay(data.printPageDelay());
+  settings->SetResolution(data.resolution());
+  settings->SetDuplex(data.duplex());
+  settings->SetIsInitializedFromPrinter(data.isInitializedFromPrinter());
+  settings->SetIsInitializedFromPrefs(data.isInitializedFromPrefs());
+
+  return NS_OK;
+}
+
+/** ---------------------------------------------------
+ *  Helper function - Creates the "prefix" for the pref
+ *  It is either "print."
+ *  or "print.printer_<print name>."
+ */
+const char* nsPrintSettingsService::GetPrefName(const char* aPrefName,
+                                                const nsAString& aPrinterName) {
+  if (!aPrefName || !*aPrefName) {
+    NS_ERROR("Must have a valid pref name!");
+    return aPrefName;
+  }
+
+  mPrefName.AssignLiteral("print.");
+
+  if (aPrinterName.Length()) {
+    mPrefName.AppendLiteral("printer_");
+    AppendUTF16toUTF8(aPrinterName, mPrefName);
+    mPrefName.Append('.');
+  }
+  mPrefName += aPrefName;
+
+  return mPrefName.get();
+}
+
+/**
+ *  This will either read in the generic prefs (not specific to a printer)
+ *  or read the prefs in using the printer name to qualify.
+ *  It is either "print.attr_name" or "print.printer_HPLasr5.attr_name"
+ */
+nsresult nsPrintSettingsService::ReadPrefs(nsIPrintSettings* aPS,
+                                           const nsAString& aPrinterName,
+                                           uint32_t aFlags) {
+  NS_ENSURE_ARG_POINTER(aPS);
+
+  bool noValidPrefsFound = true;
+  bool b;
+  nsAutoString str;
+  int32_t iVal;
+  double dbl;
+
+#define GETBOOLPREF(_prefname, _retval) \
+  NS_SUCCEEDED(                         \
+      Preferences::GetBool(GetPrefName(_prefname, aPrinterName), _retval))
+
+#define GETSTRPREF(_prefname, _retval) \
+  NS_SUCCEEDED(                        \
+      Preferences::GetString(GetPrefName(_prefname, aPrinterName), _retval))
+
+#define GETINTPREF(_prefname, _retval) \
+  NS_SUCCEEDED(                        \
+      Preferences::GetInt(GetPrefName(_prefname, aPrinterName), _retval))
+
+#define GETDBLPREF(_prefname, _retval) \
+  NS_SUCCEEDED(ReadPrefDouble(GetPrefName(_prefname, aPrinterName), _retval))
+
+  bool gotPaperSizeFromPrefs = false;
+  int16_t paperSizeUnit;
+  double paperWidth, paperHeight;
+
+  // Paper size prefs are read as a group
+  if (aFlags & nsIPrintSettings::kInitSavePaperSize) {
+    gotPaperSizeFromPrefs = GETINTPREF(kPrintPaperSizeUnit, &iVal) &&
+                            GETDBLPREF(kPrintPaperWidth, paperWidth) &&
+                            GETDBLPREF(kPrintPaperHeight, paperHeight) &&
+                            GETSTRPREF(kPrintPaperId, str);
+    paperSizeUnit = (int16_t)iVal;
+
+    if (gotPaperSizeFromPrefs &&
+        paperSizeUnit != nsIPrintSettings::kPaperSizeInches &&
+        paperSizeUnit != nsIPrintSettings::kPaperSizeMillimeters) {
+      gotPaperSizeFromPrefs = false;
+    }
+
+    if (gotPaperSizeFromPrefs) {
+      // Bug 315687: Sanity check paper size to avoid paper size values in
+      // mm when the size unit flag is inches. The value 100 is arbitrary
+      // and can be changed.
+      gotPaperSizeFromPrefs =
+          (paperSizeUnit != nsIPrintSettings::kPaperSizeInches) ||
+          (paperWidth < 100.0) || (paperHeight < 100.0);
+    }
+
+    if (gotPaperSizeFromPrefs) {
+      aPS->SetPaperSizeUnit(paperSizeUnit);
+      aPS->SetPaperWidth(paperWidth);
+      aPS->SetPaperHeight(paperHeight);
+      aPS->SetPaperId(str);
+      noValidPrefsFound = false;
+    }
+  }
+
+  nsIntSize pageSizeInTwips;  // to sanity check margins
+  if (!gotPaperSizeFromPrefs) {
+    aPS->GetPaperSizeUnit(&paperSizeUnit);
+    aPS->GetPaperWidth(&paperWidth);
+    aPS->GetPaperHeight(&paperHeight);
+  }
+  if (paperSizeUnit == nsIPrintSettings::kPaperSizeMillimeters) {
+    pageSizeInTwips = nsIntSize((int)NS_MILLIMETERS_TO_TWIPS(paperWidth),
+                                (int)NS_MILLIMETERS_TO_TWIPS(paperHeight));
+  } else {
+    pageSizeInTwips = nsIntSize((int)NS_INCHES_TO_TWIPS(paperWidth),
+                                (int)NS_INCHES_TO_TWIPS(paperHeight));
+  }
+
+  auto MarginIsOK = [&pageSizeInTwips](const nsIntMargin& aMargin) {
+    return aMargin.top >= 0 && aMargin.right >= 0 && aMargin.bottom >= 0 &&
+           aMargin.left >= 0 && aMargin.LeftRight() < pageSizeInTwips.width &&
+           aMargin.TopBottom() < pageSizeInTwips.height;
+  };
+
+  if (aFlags & nsIPrintSettings::kInitSaveUnwriteableMargins) {
+    nsIntMargin margin;
+    bool allPrefsRead =
+        GETINTPREF(kUnwriteableMarginTopTwips, &margin.top.value) &&
+        GETINTPREF(kUnwriteableMarginRightTwips, &margin.right.value) &&
+        GETINTPREF(kUnwriteableMarginBottomTwips, &margin.bottom.value) &&
+        GETINTPREF(kUnwriteableMarginLeftTwips, &margin.left.value);
+    if (!allPrefsRead) {
+      // We failed to read the new unwritable margin twips prefs. Try to read
+      // the old ones in case they exist.
+      allPrefsRead = ReadInchesIntToTwipsPref(
+                         GetPrefName(kUnwriteableMarginTop, aPrinterName),
+                         margin.top.value) &&
+                     ReadInchesIntToTwipsPref(
+                         GetPrefName(kUnwriteableMarginLeft, aPrinterName),
+                         margin.left.value) &&
+                     ReadInchesIntToTwipsPref(
+                         GetPrefName(kUnwriteableMarginBottom, aPrinterName),
+                         margin.bottom.value) &&
+                     ReadInchesIntToTwipsPref(
+                         GetPrefName(kUnwriteableMarginRight, aPrinterName),
+                         margin.right.value);
+    }
+    // SetUnwriteableMarginInTwips does its own validation and drops negative
+    // values individually.  We still want to block overly large values though,
+    // so we do that part of MarginIsOK manually.
+    if (allPrefsRead && margin.LeftRight() < pageSizeInTwips.width &&
+        margin.TopBottom() < pageSizeInTwips.height) {
+      aPS->SetUnwriteableMarginInTwips(margin);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveMargins) {
+    int32_t halfInch = NS_INCHES_TO_INT_TWIPS(0.5);
+    nsIntMargin margin(halfInch, halfInch, halfInch, halfInch);
+    bool prefRead = ReadInchesToTwipsPref(GetPrefName(kMarginTop, aPrinterName),
+                                          margin.top.value);
+    prefRead = ReadInchesToTwipsPref(GetPrefName(kMarginLeft, aPrinterName),
+                                     margin.left.value) ||
+               prefRead;
+    prefRead = ReadInchesToTwipsPref(GetPrefName(kMarginBottom, aPrinterName),
+                                     margin.bottom.value) ||
+               prefRead;
+
+    prefRead = ReadInchesToTwipsPref(GetPrefName(kMarginRight, aPrinterName),
+                                     margin.right.value) ||
+               prefRead;
+    if (prefRead && MarginIsOK(margin)) {
+      aPS->SetMarginInTwips(margin);
+      noValidPrefsFound = false;
+
+      prefRead = GETBOOLPREF(kIgnoreUnwriteableMargins, &b);
+      if (prefRead) {
+        aPS->SetIgnoreUnwriteableMargins(b);
+      }
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveEdges) {
+    nsIntMargin margin(0, 0, 0, 0);
+    bool prefRead = ReadInchesIntToTwipsPref(
+        GetPrefName(kEdgeTop, aPrinterName), margin.top.value);
+    prefRead = ReadInchesIntToTwipsPref(GetPrefName(kEdgeLeft, aPrinterName),
+                                        margin.left.value) ||
+               prefRead;
+
+    prefRead = ReadInchesIntToTwipsPref(GetPrefName(kEdgeBottom, aPrinterName),
+                                        margin.bottom.value) ||
+               prefRead;
+
+    prefRead = ReadInchesIntToTwipsPref(GetPrefName(kEdgeRight, aPrinterName),
+                                        margin.right.value) ||
+               prefRead;
+    ;
+    if (prefRead && MarginIsOK(margin)) {
+      aPS->SetEdgeInTwips(margin);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveHeaderLeft) {
+    if (GETSTRPREF(kPrintHeaderStrLeft, str)) {
+      aPS->SetHeaderStrLeft(str);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveHeaderCenter) {
+    if (GETSTRPREF(kPrintHeaderStrCenter, str)) {
+      aPS->SetHeaderStrCenter(str);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveHeaderRight) {
+    if (GETSTRPREF(kPrintHeaderStrRight, str)) {
+      aPS->SetHeaderStrRight(str);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveFooterLeft) {
+    if (GETSTRPREF(kPrintFooterStrLeft, str)) {
+      aPS->SetFooterStrLeft(str);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveFooterCenter) {
+    if (GETSTRPREF(kPrintFooterStrCenter, str)) {
+      aPS->SetFooterStrCenter(str);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveFooterRight) {
+    if (GETSTRPREF(kPrintFooterStrRight, str)) {
+      aPS->SetFooterStrRight(str);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveBGColors) {
+    if (GETBOOLPREF(kPrintBGColors, &b)) {
+      aPS->SetPrintBGColors(b);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveBGImages) {
+    if (GETBOOLPREF(kPrintBGImages, &b)) {
+      aPS->SetPrintBGImages(b);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveReversed) {
+    if (GETBOOLPREF(kPrintReversed, &b)) {
+      aPS->SetPrintReversed(b);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveInColor) {
+    if (GETBOOLPREF(kPrintInColor, &b)) {
+      aPS->SetPrintInColor(b);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveOrientation) {
+    if (GETINTPREF(kPrintOrientation, &iVal) &&
+        (iVal == nsIPrintSettings::kPortraitOrientation ||
+         iVal == nsIPrintSettings::kLandscapeOrientation)) {
+      aPS->SetOrientation(iVal);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSavePrintToFile) {
+    if (GETBOOLPREF(kPrintToFile, &b)) {
+      aPS->SetOutputDestination(
+          b ? nsIPrintSettings::kOutputDestinationFile
+            : nsIPrintSettings::kOutputDestinationPrinter);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveToFileName) {
+    if (GETSTRPREF(kPrintToFileName, str)) {
+      if (StringEndsWith(str, u".ps"_ns)) {
+        // We only support PDF since bug 1425188 landed.  Users may still have
+        // prefs with .ps filenames if they last saved a file as Postscript
+        // though, so we fix that up here.  (The pref values will be
+        // overwritten the next time they save to file as a PDF.)
+        str.Truncate(str.Length() - 2);
+        str.AppendLiteral("pdf");
+      }
+      aPS->SetToFileName(str);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSavePageDelay) {
+    // milliseconds
+    if (GETINTPREF(kPrintPageDelay, &iVal) && iVal >= 0 && iVal <= 1000) {
+      aPS->SetPrintPageDelay(iVal);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveShrinkToFit) {
+    if (GETBOOLPREF(kPrintShrinkToFit, &b)) {
+      aPS->SetShrinkToFit(b);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveScaling) {
+    // The limits imposed here are fairly arbitrary and mainly intended to
+    // purge bad values which tend to be negative and/or very large.  If we
+    // get complaints from users that settings outside these values "aren't
+    // saved" then we can consider increasing them.
+    if (GETDBLPREF(kPrintScaling, dbl) && dbl >= 0.05 && dbl <= 20) {
+      aPS->SetScaling(dbl);
+      noValidPrefsFound = false;
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveDuplex) {
+    if (GETINTPREF(kPrintDuplex, &iVal)) {
+      aPS->SetDuplex(iVal);
+      noValidPrefsFound = false;
+    }
+  }
+
+  // Not Reading In:
+  //   Number of Copies
+  //   Print Resolution
+
+  return noValidPrefsFound ? NS_ERROR_NOT_AVAILABLE : NS_OK;
+}
+
+nsresult nsPrintSettingsService::WritePrefs(nsIPrintSettings* aPS,
+                                            const nsAString& aPrinterName,
+                                            uint32_t aFlags) {
+  NS_ENSURE_ARG_POINTER(aPS);
+
+  if (aFlags & nsIPrintSettings::kInitSaveMargins) {
+    nsIntMargin margin = aPS->GetMarginInTwips();
+    WriteInchesFromTwipsPref(GetPrefName(kMarginTop, aPrinterName), margin.top);
+    WriteInchesFromTwipsPref(GetPrefName(kMarginLeft, aPrinterName),
+                             margin.left);
+    WriteInchesFromTwipsPref(GetPrefName(kMarginBottom, aPrinterName),
+                             margin.bottom);
+    WriteInchesFromTwipsPref(GetPrefName(kMarginRight, aPrinterName),
+                             margin.right);
+    Preferences::SetBool(GetPrefName(kIgnoreUnwriteableMargins, aPrinterName),
+                         aPS->GetIgnoreUnwriteableMargins());
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveEdges) {
+    nsIntMargin edge = aPS->GetEdgeInTwips();
+    WriteInchesIntFromTwipsPref(GetPrefName(kEdgeTop, aPrinterName), edge.top);
+    WriteInchesIntFromTwipsPref(GetPrefName(kEdgeLeft, aPrinterName),
+                                edge.left);
+    WriteInchesIntFromTwipsPref(GetPrefName(kEdgeBottom, aPrinterName),
+                                edge.bottom);
+    WriteInchesIntFromTwipsPref(GetPrefName(kEdgeRight, aPrinterName),
+                                edge.right);
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveUnwriteableMargins) {
+    nsIntMargin unwriteableMargin = aPS->GetUnwriteableMarginInTwips();
+    Preferences::SetInt(GetPrefName(kUnwriteableMarginTopTwips, aPrinterName),
+                        unwriteableMargin.top);
+    Preferences::SetInt(GetPrefName(kUnwriteableMarginLeftTwips, aPrinterName),
+                        unwriteableMargin.left);
+    Preferences::SetInt(
+        GetPrefName(kUnwriteableMarginBottomTwips, aPrinterName),
+        unwriteableMargin.bottom);
+    Preferences::SetInt(GetPrefName(kUnwriteableMarginRightTwips, aPrinterName),
+                        unwriteableMargin.right);
+
+    // Remove the old unwriteableMargin prefs.
+    Preferences::ClearUser(GetPrefName(kUnwriteableMarginTop, aPrinterName));
+    Preferences::ClearUser(GetPrefName(kUnwriteableMarginRight, aPrinterName));
+    Preferences::ClearUser(GetPrefName(kUnwriteableMarginBottom, aPrinterName));
+    Preferences::ClearUser(GetPrefName(kUnwriteableMarginLeft, aPrinterName));
+  }
+
+  // Paper size prefs are saved as a group
+  if (aFlags & nsIPrintSettings::kInitSavePaperSize) {
+    int16_t sizeUnit;
+    double width, height;
+    nsString name;
+
+    if (NS_SUCCEEDED(aPS->GetPaperSizeUnit(&sizeUnit)) &&
+        NS_SUCCEEDED(aPS->GetPaperWidth(&width)) &&
+        NS_SUCCEEDED(aPS->GetPaperHeight(&height)) &&
+        NS_SUCCEEDED(aPS->GetPaperId(name))) {
+      Preferences::SetInt(GetPrefName(kPrintPaperSizeUnit, aPrinterName),
+                          int32_t(sizeUnit));
+      WritePrefDouble(GetPrefName(kPrintPaperWidth, aPrinterName), width);
+      WritePrefDouble(GetPrefName(kPrintPaperHeight, aPrinterName), height);
+      Preferences::SetString(GetPrefName(kPrintPaperId, aPrinterName), name);
+    }
+  }
+
+  bool b;
+  nsString uStr;
+  int32_t iVal;
+  double dbl;
+
+  if (aFlags & nsIPrintSettings::kInitSaveHeaderLeft) {
+    if (NS_SUCCEEDED(aPS->GetHeaderStrLeft(uStr))) {
+      Preferences::SetString(GetPrefName(kPrintHeaderStrLeft, aPrinterName),
+                             uStr);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveHeaderCenter) {
+    if (NS_SUCCEEDED(aPS->GetHeaderStrCenter(uStr))) {
+      Preferences::SetString(GetPrefName(kPrintHeaderStrCenter, aPrinterName),
+                             uStr);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveHeaderRight) {
+    if (NS_SUCCEEDED(aPS->GetHeaderStrRight(uStr))) {
+      Preferences::SetString(GetPrefName(kPrintHeaderStrRight, aPrinterName),
+                             uStr);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveFooterLeft) {
+    if (NS_SUCCEEDED(aPS->GetFooterStrLeft(uStr))) {
+      Preferences::SetString(GetPrefName(kPrintFooterStrLeft, aPrinterName),
+                             uStr);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveFooterCenter) {
+    if (NS_SUCCEEDED(aPS->GetFooterStrCenter(uStr))) {
+      Preferences::SetString(GetPrefName(kPrintFooterStrCenter, aPrinterName),
+                             uStr);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveFooterRight) {
+    if (NS_SUCCEEDED(aPS->GetFooterStrRight(uStr))) {
+      Preferences::SetString(GetPrefName(kPrintFooterStrRight, aPrinterName),
+                             uStr);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveBGColors) {
+    b = aPS->GetPrintBGColors();
+    Preferences::SetBool(GetPrefName(kPrintBGColors, aPrinterName), b);
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveBGImages) {
+    b = aPS->GetPrintBGImages();
+    Preferences::SetBool(GetPrefName(kPrintBGImages, aPrinterName), b);
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveReversed) {
+    if (NS_SUCCEEDED(aPS->GetPrintReversed(&b))) {
+      Preferences::SetBool(GetPrefName(kPrintReversed, aPrinterName), b);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveInColor) {
+    if (NS_SUCCEEDED(aPS->GetPrintInColor(&b))) {
+      Preferences::SetBool(GetPrefName(kPrintInColor, aPrinterName), b);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveOrientation) {
+    if (NS_SUCCEEDED(aPS->GetOrientation(&iVal))) {
+      Preferences::SetInt(GetPrefName(kPrintOrientation, aPrinterName), iVal);
+    }
+  }
+
+  // Only the general version of this pref is saved
+  if ((aFlags & nsIPrintSettings::kInitSavePrinterName) &&
+      aPrinterName.IsEmpty()) {
+    if (NS_SUCCEEDED(aPS->GetPrinterName(uStr))) {
+      Preferences::SetString(kPrinterName, uStr);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSavePrintToFile) {
+    Preferences::SetBool(GetPrefName(kPrintToFile, aPrinterName),
+                         aPS->GetOutputDestination() ==
+                             nsIPrintSettings::kOutputDestinationFile);
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveToFileName) {
+    if (NS_SUCCEEDED(aPS->GetToFileName(uStr))) {
+      Preferences::SetString(GetPrefName(kPrintToFileName, aPrinterName), uStr);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSavePageDelay) {
+    if (NS_SUCCEEDED(aPS->GetPrintPageDelay(&iVal))) {
+      Preferences::SetInt(GetPrefName(kPrintPageDelay, aPrinterName), iVal);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveShrinkToFit) {
+    if (NS_SUCCEEDED(aPS->GetShrinkToFit(&b))) {
+      Preferences::SetBool(GetPrefName(kPrintShrinkToFit, aPrinterName), b);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveScaling) {
+    if (NS_SUCCEEDED(aPS->GetScaling(&dbl))) {
+      WritePrefDouble(GetPrefName(kPrintScaling, aPrinterName), dbl);
+    }
+  }
+
+  if (aFlags & nsIPrintSettings::kInitSaveDuplex) {
+    if (NS_SUCCEEDED(aPS->GetDuplex(&iVal))) {
+      Preferences::SetInt(GetPrefName(kPrintDuplex, aPrinterName), iVal);
+    }
+  }
+
+  // Not Writing Out:
+  //   Number of Copies
+  //   Print Resolution
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsService::GetDefaultPrintSettingsForPrinting(
+    nsIPrintSettings** aPrintSettings) {
+  nsresult rv = CreateNewPrintSettings(aPrintSettings);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsIPrintSettings* settings = *aPrintSettings;
+
+  // For security reasons, we don't pass the printer name to content processes.
+  // Once bug 1776169 is fixed, we can just assert that this is the parent
+  // process.
+  bool usePrinterName = XRE_IsParentProcess();
+
+  if (usePrinterName) {
+    nsAutoString printerName;
+    settings->GetPrinterName(printerName);
+    if (printerName.IsEmpty()) {
+      GetLastUsedPrinterName(printerName);
+      settings->SetPrinterName(printerName);
+    }
+    InitPrintSettingsFromPrinter(printerName, settings);
+  }
+
+  InitPrintSettingsFromPrefs(settings, usePrinterName,
+                             nsIPrintSettings::kInitSaveAll);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsService::CreateNewPrintSettings(
+    nsIPrintSettings** aNewPrintSettings) {
+  return _CreatePrintSettings(aNewPrintSettings);
+}
+
+NS_IMETHODIMP
+nsPrintSettingsService::GetLastUsedPrinterName(
+    nsAString& aLastUsedPrinterName) {
+  MOZ_ASSERT(XRE_IsParentProcess());
+
+  aLastUsedPrinterName.Truncate();
+  Preferences::GetString(kPrinterName, aLastUsedPrinterName);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsService::InitPrintSettingsFromPrinter(
+    const nsAString& aPrinterName, nsIPrintSettings* aPrintSettings) {
+  // Don't get print settings from the printer in the child when printing via
+  // parent, these will be retrieved in the parent later in the print process.
+  if (XRE_IsContentProcess()) {
+    return NS_OK;
+  }
+
+  NS_ENSURE_ARG_POINTER(aPrintSettings);
+
+#ifdef DEBUG
+  nsString printerName;
+  aPrintSettings->GetPrinterName(printerName);
+  if (!printerName.Equals(aPrinterName)) {
+    NS_WARNING("Printer names should match!");
+  }
+#endif
+
+  bool isInitialized;
+  aPrintSettings->GetIsInitializedFromPrinter(&isInitialized);
+  if (isInitialized) return NS_OK;
+
+  nsresult rv;
+  nsCOMPtr<nsIPrinterList> printerList =
+      do_GetService(NS_PRINTER_LIST_CONTRACTID, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = printerList->InitPrintSettingsFromPrinter(aPrinterName, aPrintSettings);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  aPrintSettings->SetIsInitializedFromPrinter(true);
+  return rv;
+}
+
+/** ---------------------------------------------------
+ *  Helper function - Returns either the name or sets the length to zero
+ */
+static nsresult GetAdjustedPrinterName(nsIPrintSettings* aPS, bool aUsePNP,
+                                       nsAString& aPrinterName) {
+  NS_ENSURE_ARG_POINTER(aPS);
+
+  aPrinterName.Truncate();
+  if (!aUsePNP) return NS_OK;
+
+  // Get the Printer Name from the PrintSettings
+  // to use as a prefix for Pref Names
+  nsresult rv = aPS->GetPrinterName(aPrinterName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Convert any whitespaces, carriage returns or newlines to _
+  // The below algorithm is supposedly faster than using iterators
+  constexpr auto replSubstr = u"_"_ns;
+  const char* replaceStr = " \n\r";
+
+  int32_t x;
+  for (x = 0; x < (int32_t)strlen(replaceStr); x++) {
+    char16_t uChar = replaceStr[x];
+
+    int32_t i = 0;
+    while ((i = aPrinterName.FindChar(uChar, i)) != kNotFound) {
+      aPrinterName.Replace(i, 1, replSubstr);
+      i++;
+    }
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsService::InitPrintSettingsFromPrefs(nsIPrintSettings* aPS,
+                                                   bool aUsePNP,
+                                                   uint32_t aFlags) {
+  NS_ENSURE_ARG_POINTER(aPS);
+
+  bool isInitialized;
+  aPS->GetIsInitializedFromPrefs(&isInitialized);
+
+  if (isInitialized) {
+    return NS_OK;
+  }
+
+  auto globalPrintSettings = aFlags;
+#ifndef MOZ_WIDGET_ANDROID
+  globalPrintSettings &= nsIPrintSettings::kGlobalSettings;
+#endif
+
+  nsAutoString prtName;
+  // read any non printer specific prefs
+  // with empty printer name
+  nsresult rv = ReadPrefs(aPS, prtName, globalPrintSettings);
+  if (NS_FAILED(rv) && rv != NS_ERROR_NOT_AVAILABLE) {
+    NS_WARNING("ReadPrefs failed");
+  }
+
+  // Get the Printer Name from the PrintSettings to use as a prefix for Pref
+  // Names
+  rv = GetAdjustedPrinterName(aPS, aUsePNP, prtName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (prtName.IsEmpty()) {
+    NS_WARNING("Caller should supply a printer name.");
+    return NS_OK;
+  }
+
+  // Now read any printer specific prefs
+  rv = ReadPrefs(aPS, prtName, aFlags);
+  if (NS_SUCCEEDED(rv)) {
+    aPS->SetIsInitializedFromPrefs(true);
+  }
+
+  return NS_OK;
+}
+
+/**
+ *  Save all of the printer settings; if we can find a printer name, save
+ *  printer-specific preferences. Otherwise, save generic ones.
+ */
+nsresult nsPrintSettingsService::MaybeSavePrintSettingsToPrefs(
+    nsIPrintSettings* aPS, uint32_t aFlags) {
+  NS_ENSURE_ARG_POINTER(aPS);
+  MOZ_DIAGNOSTIC_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
+  MOZ_ASSERT(!(aFlags & nsIPrintSettings::kInitSavePrinterName),
+             "Use SaveLastUsedPrintNameToPrefs");
+
+  if (!Preferences::GetBool("print.save_print_settings", false)) {
+    return NS_OK;
+  }
+
+  // Get the printer name from the PrinterSettings for an optional prefix.
+  nsAutoString prtName;
+  nsresult rv = GetAdjustedPrinterName(aPS, true, prtName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+#ifndef MOZ_WIDGET_ANDROID
+  // On most platforms we should always use a prefix when saving print settings
+  // to prefs.  Saving without a prefix risks breaking printing for users
+  // without a good way for us to fix things for them (unprefixed prefs act as
+  // defaults and can result in values being inappropriately propagated to
+  // prefixed prefs).
+  if (prtName.IsEmpty()) {
+    MOZ_DIAGNOSTIC_ASSERT(false, "Print settings must be saved with a prefix");
+    return NS_ERROR_FAILURE;
+  }
+#endif
+
+  return WritePrefs(aPS, prtName, aFlags);
+}
+
+nsresult nsPrintSettingsService::MaybeSaveLastUsedPrinterNameToPrefs(
+    const nsAString& aPrinterName) {
+  MOZ_DIAGNOSTIC_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
+
+  if (!Preferences::GetBool("print.save_print_settings", false)) {
+    return NS_OK;
+  }
+
+  if (!aPrinterName.IsEmpty()) {
+    Preferences::SetString(kPrinterName, aPrinterName);
+  }
+  return NS_OK;
+}
+
+//-----------------------------------------------------
+//-- Protected Methods --------------------------------
+//-----------------------------------------------------
+nsresult nsPrintSettingsService::ReadPrefDouble(const char* aPrefId,
+                                                double& aVal) {
+  NS_ENSURE_ARG_POINTER(aPrefId);
+
+  nsAutoCString str;
+  nsresult rv = Preferences::GetCString(aPrefId, str);
+  if (NS_FAILED(rv) || str.IsEmpty()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  double value = str.ToDouble(&rv);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  aVal = value;
+  return NS_OK;
+}
+
+nsresult nsPrintSettingsService::WritePrefDouble(const char* aPrefId,
+                                                 double aVal) {
+  NS_ENSURE_ARG_POINTER(aPrefId);
+
+  nsAutoCString str;
+  str.AppendFloat(aVal);
+  return Preferences::SetCString(aPrefId, str);
+}
+
+bool nsPrintSettingsService::ReadInchesToTwipsPref(const char* aPrefId,
+                                                   int32_t& aTwips) {
+  nsAutoString str;
+  nsresult rv = Preferences::GetString(aPrefId, str);
+  if (NS_FAILED(rv) || str.IsEmpty()) {
+    return false;
+  }
+
+  float inches = str.ToFloat(&rv);
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  aTwips = NS_INCHES_TO_INT_TWIPS(inches);
+  return true;
+}
+
+void nsPrintSettingsService::WriteInchesFromTwipsPref(const char* aPrefId,
+                                                      int32_t aTwips) {
+  double inches = NS_TWIPS_TO_INCHES(aTwips);
+  nsAutoCString inchesStr;
+  inchesStr.AppendFloat(inches);
+
+  Preferences::SetCString(aPrefId, inchesStr);
+}
+
+bool nsPrintSettingsService::ReadInchesIntToTwipsPref(const char* aPrefId,
+                                                      int32_t& aTwips) {
+  int32_t value;
+  nsresult rv = Preferences::GetInt(aPrefId, &value);
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  aTwips = NS_INCHES_TO_INT_TWIPS(float(value) / 100.0f);
+  return true;
+}
+
+void nsPrintSettingsService::WriteInchesIntFromTwipsPref(const char* aPrefId,
+                                                         int32_t aTwips) {
+  Preferences::SetInt(aPrefId,
+                      int32_t(NS_TWIPS_TO_INCHES(aTwips) * 100.0f + 0.5f));
+}
+
+void nsPrintSettingsService::ReadJustification(const char* aPrefId,
+                                               int16_t& aJust,
+                                               int16_t aInitValue) {
+  aJust = aInitValue;
+  nsAutoString justStr;
+  if (NS_SUCCEEDED(Preferences::GetString(aPrefId, justStr))) {
+    if (justStr.EqualsASCII(kJustRight)) {
+      aJust = nsIPrintSettings::kJustRight;
+    } else if (justStr.EqualsASCII(kJustCenter)) {
+      aJust = nsIPrintSettings::kJustCenter;
+    } else {
+      aJust = nsIPrintSettings::kJustLeft;
+    }
+  }
+}
+
+//---------------------------------------------------
+void nsPrintSettingsService::WriteJustification(const char* aPrefId,
+                                                int16_t aJust) {
+  switch (aJust) {
+    case nsIPrintSettings::kJustLeft:
+      Preferences::SetCString(aPrefId, kJustLeft);
+      break;
+
+    case nsIPrintSettings::kJustCenter:
+      Preferences::SetCString(aPrefId, kJustCenter);
+      break;
+
+    case nsIPrintSettings::kJustRight:
+      Preferences::SetCString(aPrefId, kJustRight);
+      break;
+  }  // switch
+}
diff --git a/widget/nsPrintSettingsService.h b/widget/nsPrintSettingsService.h
new file mode 100644
index 0000000000..43965455a1
--- /dev/null
+++ b/widget/nsPrintSettingsService.h
@@ -0,0 +1,87 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrintSettingsService_h
+#define nsPrintSettingsService_h
+
+#include "nsCOMPtr.h"
+#include "nsIPrintSettings.h"
+#include "nsIPrintSettingsService.h"
+#include "nsString.h"
+#include "nsFont.h"
+
+/**
+ * Class nsPrintSettingsService.  Base class for the platform specific widget
+ * subclasses to inherit from.
+ */
+class nsPrintSettingsService : public nsIPrintSettingsService {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIPRINTSETTINGSSERVICE
+
+  nsPrintSettingsService() = default;
+
+  /**
+   * method Init
+   *  Initializes member variables. Every consumer that does manual
+   *  creation (instead of do_CreateInstance) needs to call this method
+   *  immediately after instantiation.
+   */
+  virtual nsresult Init();
+
+ private:
+  // Copying is not supported.
+  nsPrintSettingsService(const nsPrintSettingsService& x) = delete;
+  nsPrintSettingsService& operator=(const nsPrintSettingsService& x) = delete;
+
+ protected:
+  virtual ~nsPrintSettingsService() = default;
+
+  void ReadBitFieldPref(const char* aPrefId, int32_t anOption);
+  void WriteBitFieldPref(const char* aPrefId, int32_t anOption);
+  void ReadJustification(const char* aPrefId, int16_t& aJust,
+                         int16_t aInitValue);
+  void WriteJustification(const char* aPrefId, int16_t aJust);
+  bool ReadInchesToTwipsPref(const char* aPrefId, int32_t& aTwips);
+  void WriteInchesFromTwipsPref(const char* aPrefId, int32_t aTwips);
+  bool ReadInchesIntToTwipsPref(const char* aPrefId, int32_t& aTwips);
+  void WriteInchesIntFromTwipsPref(const char* aPrefId, int32_t aTwips);
+
+  nsresult ReadPrefDouble(const char* aPrefId, double& aVal);
+  nsresult WritePrefDouble(const char* aPrefId, double aVal);
+
+  /**
+   * method ReadPrefs
+   * @param aPS          a pointer to the printer settings
+   * @param aPrinterName the name of the printer for which to read prefs
+   * @param aFlags       flag specifying which prefs to read
+   */
+  virtual nsresult ReadPrefs(nsIPrintSettings* aPS,
+                             const nsAString& aPrinterName, uint32_t aFlags);
+  /**
+   * method WritePrefs
+   * @param aPS          a pointer to the printer settings
+   * @param aPrinterName the name of the printer for which to write prefs
+   * @param aFlags       flag specifying which prefs to read
+   */
+  virtual nsresult WritePrefs(nsIPrintSettings* aPS,
+                              const nsAString& aPrinterName, uint32_t aFlags);
+
+  const char* GetPrefName(const char* aPrefName, const nsAString& aPrinterName);
+
+  /**
+   * method _CreatePrintSettings
+   *   May be implemented by the platform-specific derived class
+   *
+   * @return             printer settings instance
+   */
+  virtual nsresult _CreatePrintSettings(nsIPrintSettings** _retval) = 0;
+
+  // Members
+  nsCString mPrefName;
+};
+
+#endif  // nsPrintSettingsService_h
diff --git a/widget/nsPrinterBase.cpp b/widget/nsPrinterBase.cpp
new file mode 100644
index 0000000000..7e01b9e12f
--- /dev/null
+++ b/widget/nsPrinterBase.cpp
@@ -0,0 +1,247 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrinterBase.h"
+#include "nsPaperMargin.h"
+#include <utility>
+#include "nsPaper.h"
+#include "nsIPrintSettings.h"
+#include "nsPrintSettingsService.h"
+#include "PrintBackgroundTask.h"
+#include "mozilla/dom/Promise.h"
+
+using namespace mozilla;
+using mozilla::dom::Promise;
+using mozilla::gfx::MarginDouble;
+
+// The maximum error when considering a paper size equal, in points.
+// There is some variance in the actual sizes returned by printer drivers and
+// print servers for paper sizes. This is a best-guess based on initial
+// telemetry which should catch most near-miss dimensions. This should let us
+// get consistent paper size names even when the size isn't quite exactly the
+// correct size.
+static constexpr double kPaperSizePointsEpsilon = 4.0;
+
+// Basic implementation of nsIPrinterInfo
+class nsPrinterInfo : public nsIPrinterInfo {
+ public:
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS(nsPrinterInfo)
+  NS_DECL_NSIPRINTERINFO
+  nsPrinterInfo() = delete;
+  nsPrinterInfo(nsPrinterBase& aPrinter,
+                const nsPrinterBase::PrinterInfo& aPrinterInfo)
+      : mDefaultSettings(
+            CreatePlatformPrintSettings(aPrinterInfo.mDefaultSettings)) {
+    mPaperList.SetCapacity(aPrinterInfo.mPaperList.Length());
+    for (const PaperInfo& info : aPrinterInfo.mPaperList) {
+      mPaperList.AppendElement(MakeRefPtr<nsPaper>(aPrinter, info));
+    }
+
+    // Update the printer's default settings with the global settings.
+    nsCOMPtr<nsIPrintSettingsService> printSettingsSvc =
+        do_GetService("@mozilla.org/gfx/printsettings-service;1");
+    if (printSettingsSvc) {
+      // Passing false as the second parameter means we don't get the printer
+      // specific settings.
+      printSettingsSvc->InitPrintSettingsFromPrefs(
+          mDefaultSettings, false, nsIPrintSettings::kInitSaveAll);
+    }
+  }
+
+ private:
+  virtual ~nsPrinterInfo() = default;
+
+  nsTArray<RefPtr<nsIPaper>> mPaperList;
+  RefPtr<nsIPrintSettings> mDefaultSettings;
+};
+
+NS_IMETHODIMP
+nsPrinterInfo::GetPaperList(nsTArray<RefPtr<nsIPaper>>& aPaperList) {
+  aPaperList = mPaperList.Clone();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrinterInfo::GetDefaultSettings(nsIPrintSettings** aDefaultSettings) {
+  NS_ENSURE_ARG_POINTER(aDefaultSettings);
+  MOZ_ASSERT(mDefaultSettings);
+  RefPtr<nsIPrintSettings> settings = mDefaultSettings;
+  settings.forget(aDefaultSettings);
+  return NS_OK;
+}
+
+NS_IMPL_CYCLE_COLLECTION(nsPrinterInfo, mPaperList, mDefaultSettings)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsPrinterInfo)
+  NS_INTERFACE_MAP_ENTRY(nsIPrinterInfo)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIPrinterInfo)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsPrinterInfo)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsPrinterInfo)
+
+template <typename Index, Index Size, typename Value>
+inline void ImplCycleCollectionTraverse(
+    nsCycleCollectionTraversalCallback& aCallback,
+    EnumeratedArray<Index, Size, Value>& aArray, const char* aName,
+    uint32_t aFlags = 0) {
+  aFlags |= CycleCollectionEdgeNameArrayFlag;
+  for (Value& element : aArray) {
+    ImplCycleCollectionTraverse(aCallback, element, aName, aFlags);
+  }
+}
+
+template <typename Index, Index Size, typename Value>
+inline void ImplCycleCollectionUnlink(
+    EnumeratedArray<Index, Size, Value>& aArray) {
+  for (Value& element : aArray) {
+    ImplCycleCollectionUnlink(element);
+  }
+}
+
+namespace mozilla {
+
+template <>
+void ResolveOrReject(Promise& aPromise, nsPrinterBase&,
+                     const MarginDouble& aResult) {
+  auto margin = MakeRefPtr<nsPaperMargin>(aResult);
+  aPromise.MaybeResolve(margin);
+}
+
+template <>
+void ResolveOrReject(Promise& aPromise, nsPrinterBase& aPrinter,
+                     const nsTArray<PaperInfo>& aResult) {
+  nsTArray<RefPtr<nsPaper>> result;
+  result.SetCapacity(aResult.Length());
+  for (const PaperInfo& info : aResult) {
+    result.AppendElement(MakeRefPtr<nsPaper>(aPrinter, info));
+  }
+  aPromise.MaybeResolve(result);
+}
+
+template <>
+void ResolveOrReject(Promise& aPromise, nsPrinterBase& aPrinter,
+                     const PrintSettingsInitializer& aResult) {
+  aPromise.MaybeResolve(
+      RefPtr<nsIPrintSettings>(CreatePlatformPrintSettings(aResult)));
+}
+
+template <>
+void ResolveOrReject(Promise& aPromise, nsPrinterBase& aPrinter,
+                     const nsPrinterBase::PrinterInfo& aResult) {
+  aPromise.MaybeResolve(MakeRefPtr<nsPrinterInfo>(aPrinter, aResult));
+}
+
+}  // namespace mozilla
+
+template <typename T, typename... Args>
+nsresult nsPrinterBase::AsyncPromiseAttributeGetter(
+    JSContext* aCx, Promise** aResultPromise, AsyncAttribute aAttribute,
+    BackgroundTask<T, Args...> aBackgroundTask, Args... aArgs) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  static constexpr EnumeratedArray<AsyncAttribute, AsyncAttribute::Last,
+                                   nsLiteralCString>
+      attributeKeys{"SupportsDuplex"_ns, "SupportsColor"_ns,
+                    "SupportsMonochrome"_ns, "SupportsCollation"_ns,
+                    "PrinterInfo"_ns};
+  return mozilla::AsyncPromiseAttributeGetter(
+      *this, mAsyncAttributePromises[aAttribute], aCx, aResultPromise,
+      attributeKeys[aAttribute], aBackgroundTask, std::forward<Args>(aArgs)...);
+}
+
+NS_IMETHODIMP nsPrinterBase::CopyFromWithValidation(
+    nsIPrintSettings* aSettingsToCopyFrom, JSContext* aCx,
+    Promise** aResultPromise) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aResultPromise);
+
+  ErrorResult errorResult;
+  RefPtr<dom::Promise> promise =
+      dom::Promise::Create(xpc::CurrentNativeGlobal(aCx), errorResult);
+  if (MOZ_UNLIKELY(errorResult.Failed())) {
+    return errorResult.StealNSResult();
+  }
+
+  nsCOMPtr<nsIPrintSettings> settings;
+  MOZ_ALWAYS_SUCCEEDS(aSettingsToCopyFrom->Clone(getter_AddRefs(settings)));
+  nsString printerName;
+  MOZ_ALWAYS_SUCCEEDS(GetName(printerName));
+  MOZ_ALWAYS_SUCCEEDS(settings->SetPrinterName(printerName));
+  promise->MaybeResolve(settings);
+  promise.forget(aResultPromise);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrinterBase::GetSupportsDuplex(JSContext* aCx,
+                                               Promise** aResultPromise) {
+  return AsyncPromiseAttributeGetter(aCx, aResultPromise,
+                                     AsyncAttribute::SupportsDuplex,
+                                     &nsPrinterBase::SupportsDuplex);
+}
+
+NS_IMETHODIMP nsPrinterBase::GetSupportsColor(JSContext* aCx,
+                                              Promise** aResultPromise) {
+  return AsyncPromiseAttributeGetter(aCx, aResultPromise,
+                                     AsyncAttribute::SupportsColor,
+                                     &nsPrinterBase::SupportsColor);
+}
+
+NS_IMETHODIMP nsPrinterBase::GetSupportsMonochrome(JSContext* aCx,
+                                                   Promise** aResultPromise) {
+  return AsyncPromiseAttributeGetter(aCx, aResultPromise,
+                                     AsyncAttribute::SupportsMonochrome,
+                                     &nsPrinterBase::SupportsMonochrome);
+}
+
+NS_IMETHODIMP nsPrinterBase::GetSupportsCollation(JSContext* aCx,
+                                                  Promise** aResultPromise) {
+  return AsyncPromiseAttributeGetter(aCx, aResultPromise,
+                                     AsyncAttribute::SupportsCollation,
+                                     &nsPrinterBase::SupportsCollation);
+}
+
+NS_IMETHODIMP nsPrinterBase::GetPrinterInfo(JSContext* aCx,
+                                            Promise** aResultPromise) {
+  return AsyncPromiseAttributeGetter(aCx, aResultPromise,
+                                     AsyncAttribute::PrinterInfo,
+                                     &nsPrinterBase::CreatePrinterInfo);
+}
+
+void nsPrinterBase::QueryMarginsForPaper(Promise& aPromise,
+                                         const nsString& aPaperId) {
+  return SpawnPrintBackgroundTask(*this, aPromise, "MarginsForPaper"_ns,
+                                  &nsPrinterBase::GetMarginsForPaper, aPaperId);
+}
+
+NS_IMPL_CYCLE_COLLECTION(nsPrinterBase, mAsyncAttributePromises)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsPrinterBase)
+  NS_INTERFACE_MAP_ENTRY(nsIPrinter)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIPrinter)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsPrinterBase)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsPrinterBase)
+
+nsPrinterBase::nsPrinterBase(const CommonPaperInfoArray* aPaperInfoArray)
+    : mCommonPaperInfo(aPaperInfoArray) {
+  MOZ_DIAGNOSTIC_ASSERT(aPaperInfoArray, "Localized paper info was null");
+}
+nsPrinterBase::~nsPrinterBase() = default;
+
+const PaperInfo* nsPrinterBase::FindCommonPaperSize(
+    const gfx::SizeDouble& aSize) const {
+  for (const PaperInfo& paper : *mCommonPaperInfo) {
+    if (std::abs(paper.mSize.width - aSize.width) <= kPaperSizePointsEpsilon &&
+        std::abs(paper.mSize.height - aSize.height) <=
+            kPaperSizePointsEpsilon) {
+      return &paper;
+    }
+  }
+  return nullptr;
+}
diff --git a/widget/nsPrinterBase.h b/widget/nsPrinterBase.h
new file mode 100644
index 0000000000..abd4f82705
--- /dev/null
+++ b/widget/nsPrinterBase.h
@@ -0,0 +1,114 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrinterBase_h__
+#define nsPrinterBase_h__
+
+#include "mozilla/gfx/Rect.h"
+#include "nsIPrinter.h"
+#include "nsTArray.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsISupportsImpl.h"
+#include "nsPrintSettingsImpl.h"
+#include "mozilla/EnumeratedArray.h"
+#include "mozilla/Result.h"
+
+namespace mozilla {
+
+struct PaperInfo;
+
+namespace dom {
+class Promise;
+}
+
+}  // namespace mozilla
+
+class nsPrinterBase : public nsIPrinter {
+ public:
+  using Promise = mozilla::dom::Promise;
+  using MarginDouble = mozilla::gfx::MarginDouble;
+  using PrintSettingsInitializer = mozilla::PrintSettingsInitializer;
+
+  NS_IMETHOD CopyFromWithValidation(nsIPrintSettings*, JSContext*,
+                                    Promise**) override;
+  NS_IMETHOD GetSupportsDuplex(JSContext*, Promise**) final;
+  NS_IMETHOD GetSupportsColor(JSContext*, Promise**) final;
+  NS_IMETHOD GetSupportsMonochrome(JSContext*, Promise**) final;
+  NS_IMETHOD GetSupportsCollation(JSContext*, Promise**) final;
+  NS_IMETHOD GetPrinterInfo(JSContext*, Promise**) final;
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS(nsPrinterBase)
+
+  // We require the paper info array
+  nsPrinterBase() = delete;
+
+  // No copy or move, we're an identity.
+  nsPrinterBase(const nsPrinterBase&) = delete;
+  nsPrinterBase(nsPrinterBase&&) = delete;
+
+  void QueryMarginsForPaper(Promise&, const nsString& aPaperId);
+
+  /**
+   * Caches the argument by copying it into mPrintSettingsInitializer.
+   * If mPrintSettingsInitializer is already populated this is a no-op.
+   */
+  void CachePrintSettingsInitializer(
+      const PrintSettingsInitializer& aInitializer);
+
+  // Data to pass through to create the nsPrinterInfo
+  struct PrinterInfo {
+    nsTArray<mozilla::PaperInfo> mPaperList;
+    PrintSettingsInitializer mDefaultSettings;
+  };
+
+ private:
+  enum class AsyncAttribute {
+    // If you change this list you must update attributeKeys in
+    // nsPrinterBase::AsyncPromiseAttributeGetter.
+    SupportsDuplex = 0,
+    SupportsColor,
+    SupportsMonochrome,
+    SupportsCollation,
+    PrinterInfo,
+    // Just a guard.
+    Last,
+  };
+
+  template <typename Result, typename... Args>
+  using BackgroundTask = Result (nsPrinterBase::*)(Args...) const;
+
+  // Resolves an async attribute via a background task.
+  template <typename T, typename... Args>
+  nsresult AsyncPromiseAttributeGetter(JSContext*, Promise**, AsyncAttribute,
+                                       BackgroundTask<T, Args...>,
+                                       Args... aArgs);
+
+ protected:
+  nsPrinterBase(const mozilla::CommonPaperInfoArray* aPaperInfoArray);
+  virtual ~nsPrinterBase();
+
+  // Implementation-specific methods. These must not make assumptions about
+  // which thread they run on.
+  virtual bool SupportsDuplex() const = 0;
+  virtual bool SupportsColor() const = 0;
+  virtual bool SupportsMonochrome() const = 0;
+  virtual bool SupportsCollation() const = 0;
+  virtual MarginDouble GetMarginsForPaper(nsString aPaperId) const = 0;
+  virtual PrinterInfo CreatePrinterInfo() const = 0;
+  // Searches our built-in list of commonly used PWG paper sizes for a matching,
+  // localized PaperInfo. Returns null if there is no matching size.
+  const mozilla::PaperInfo* FindCommonPaperSize(
+      const mozilla::gfx::SizeDouble& aSize) const;
+
+ private:
+  mozilla::EnumeratedArray<AsyncAttribute, AsyncAttribute::Last,
+                           RefPtr<Promise>>
+      mAsyncAttributePromises;
+  // List of built-in, commonly used paper sizes.
+  const RefPtr<const mozilla::CommonPaperInfoArray> mCommonPaperInfo;
+};
+
+#endif
diff --git a/widget/nsPrinterCUPS.cpp b/widget/nsPrinterCUPS.cpp
new file mode 100644
index 0000000000..a8656de23f
--- /dev/null
+++ b/widget/nsPrinterCUPS.cpp
@@ -0,0 +1,476 @@
+/* -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 2; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrinterCUPS.h"
+
+#include "mozilla/gfx/2D.h"
+#include "mozilla/GkRustUtils.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_print.h"
+#include "nsTHashtable.h"
+#include "nsPaper.h"
+#include "nsPrinterBase.h"
+#include "nsPrintSettingsImpl.h"
+
+using namespace mozilla;
+using MarginDouble = mozilla::gfx::MarginDouble;
+
+// Requested attributes for IPP requests, just the CUPS version now.
+static constexpr Array<const char* const, 1> requestedAttributes{
+    "cups-version"};
+
+static constexpr double kPointsPerHundredthMillimeter = 72.0 / 2540.0;
+
+static PaperInfo MakePaperInfo(const nsAString& aName,
+                               const cups_size_t& aMedia) {
+  // XXX Do we actually have the guarantee that this is utf-8?
+  NS_ConvertUTF8toUTF16 paperId(aMedia.media);  // internal paper name/ID
+  return PaperInfo(
+      paperId, aName,
+      {aMedia.width * kPointsPerHundredthMillimeter,
+       aMedia.length * kPointsPerHundredthMillimeter},
+      Some(gfx::MarginDouble{aMedia.top * kPointsPerHundredthMillimeter,
+                             aMedia.right * kPointsPerHundredthMillimeter,
+                             aMedia.bottom * kPointsPerHundredthMillimeter,
+                             aMedia.left * kPointsPerHundredthMillimeter}));
+}
+
+// Fetches the CUPS version for the print server controlling the printer. This
+// will only modify the output arguments if the fetch succeeds.
+static void FetchCUPSVersionForPrinter(const nsCUPSShim& aShim,
+                                       const cups_dest_t* const aDest,
+                                       uint64_t& aOutMajor, uint64_t& aOutMinor,
+                                       uint64_t& aOutPatch) {
+  // Make an IPP request to the server for the printer.
+  const char* const uri = aShim.cupsGetOption(
+      "printer-uri-supported", aDest->num_options, aDest->options);
+  if (!uri) {
+    return;
+  }
+
+  ipp_t* const ippRequest = aShim.ippNewRequest(IPP_OP_GET_PRINTER_ATTRIBUTES);
+
+  // Set the URI we want to use.
+  aShim.ippAddString(ippRequest, IPP_TAG_OPERATION, IPP_TAG_URI, "printer-uri",
+                     nullptr, uri);
+
+  // Set the attributes to request.
+  aShim.ippAddStrings(ippRequest, IPP_TAG_OPERATION, IPP_TAG_KEYWORD,
+                      "requested-attributes", requestedAttributes.Length,
+                      nullptr, &(requestedAttributes[0]));
+
+  // Use the default HTTP connection to query the CUPS server itself to get
+  // the CUPS version.
+  // Note that cupsDoRequest will delete the request whether it succeeds or
+  // fails, so we should not use ippDelete on it.
+  if (ipp_t* const ippResponse =
+          aShim.cupsDoRequest(CUPS_HTTP_DEFAULT, ippRequest, "/")) {
+    ipp_attribute_t* const versionAttrib =
+        aShim.ippFindAttribute(ippResponse, "cups-version", IPP_TAG_TEXT);
+    if (versionAttrib && aShim.ippGetCount(versionAttrib) == 1) {
+      const char* versionString = aShim.ippGetString(versionAttrib, 0, nullptr);
+      MOZ_ASSERT(versionString);
+      // On error, GkRustUtils::ParseSemVer will not modify its arguments.
+      GkRustUtils::ParseSemVer(
+          nsDependentCSubstring{MakeStringSpan(versionString)}, aOutMajor,
+          aOutMinor, aOutPatch);
+    }
+    aShim.ippDelete(ippResponse);
+  }
+}
+
+nsPrinterCUPS::~nsPrinterCUPS() {
+  PrinterInfoLock lock = mPrinterInfoMutex.Lock();
+  if (lock->mPrinterInfo) {
+    mShim.cupsFreeDestInfo(lock->mPrinterInfo);
+  }
+  if (lock->mPrinter) {
+    mShim.cupsFreeDests(1, lock->mPrinter);
+  }
+}
+
+NS_IMETHODIMP
+nsPrinterCUPS::GetName(nsAString& aName) {
+  GetPrinterName(aName);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrinterCUPS::GetSystemName(nsAString& aName) {
+  PrinterInfoLock lock = mPrinterInfoMutex.Lock();
+  CopyUTF8toUTF16(MakeStringSpan(lock->mPrinter->name), aName);
+  return NS_OK;
+}
+
+void nsPrinterCUPS::GetPrinterName(nsAString& aName) const {
+  if (mDisplayName.IsEmpty()) {
+    aName.Truncate();
+    PrinterInfoLock lock = mPrinterInfoMutex.Lock();
+    CopyUTF8toUTF16(MakeStringSpan(lock->mPrinter->name), aName);
+  } else {
+    aName = mDisplayName;
+  }
+}
+
+const char* nsPrinterCUPS::LocalizeMediaName(http_t& aConnection,
+                                             cups_size_t& aMedia) const {
+  // The returned string is owned by mPrinterInfo.
+  // https://www.cups.org/doc/cupspm.html#cupsLocalizeDestMedia
+  if (!mShim.cupsLocalizeDestMedia) {
+    return aMedia.media;
+  }
+  PrinterInfoLock lock = TryEnsurePrinterInfo();
+  return mShim.cupsLocalizeDestMedia(&aConnection, lock->mPrinter,
+                                     lock->mPrinterInfo,
+                                     CUPS_MEDIA_FLAGS_DEFAULT, &aMedia);
+}
+
+bool nsPrinterCUPS::SupportsDuplex() const {
+  return Supports(CUPS_SIDES, CUPS_SIDES_TWO_SIDED_PORTRAIT);
+}
+
+bool nsPrinterCUPS::SupportsMonochrome() const {
+  if (!SupportsColor()) {
+    return true;
+  }
+  return StaticPrefs::print_cups_monochrome_enabled();
+}
+
+bool nsPrinterCUPS::SupportsColor() const {
+  // CUPS 2.1 (particularly as used in Ubuntu 16) is known to have inaccurate
+  // results for CUPS_PRINT_COLOR_MODE.
+  // See https://bugzilla.mozilla.org/show_bug.cgi?id=1660658#c15
+  if (!IsCUPSVersionAtLeast(2, 2, 0)) {
+    return true;  // See comment for PrintSettingsInitializer.mPrintInColor
+  }
+  return Supports(CUPS_PRINT_COLOR_MODE, CUPS_PRINT_COLOR_MODE_AUTO) ||
+         Supports(CUPS_PRINT_COLOR_MODE, CUPS_PRINT_COLOR_MODE_COLOR) ||
+         !Supports(CUPS_PRINT_COLOR_MODE, CUPS_PRINT_COLOR_MODE_MONOCHROME);
+}
+
+bool nsPrinterCUPS::SupportsCollation() const {
+  // We can't depend on cupsGetIntegerOption existing.
+  PrinterInfoLock lock = mPrinterInfoMutex.Lock();
+  const char* const value = FindCUPSOption(lock, "printer-type");
+  if (!value) {
+    return false;
+  }
+  // If the value is non-numeric, then atoi will return 0, which will still
+  // cause this function to return false.
+  const int type = atoi(value);
+  return type & CUPS_PRINTER_COLLATE;
+}
+
+nsPrinterBase::PrinterInfo nsPrinterCUPS::CreatePrinterInfo() const {
+  Connection connection{mShim};
+  return PrinterInfo{PaperList(connection), DefaultSettings(connection)};
+}
+
+bool nsPrinterCUPS::Supports(const char* aOption, const char* aValue) const {
+  PrinterInfoLock lock = TryEnsurePrinterInfo();
+  return mShim.cupsCheckDestSupported(CUPS_HTTP_DEFAULT, lock->mPrinter,
+                                      lock->mPrinterInfo, aOption, aValue);
+}
+
+bool nsPrinterCUPS::IsCUPSVersionAtLeast(uint64_t aCUPSMajor,
+                                         uint64_t aCUPSMinor,
+                                         uint64_t aCUPSPatch) const {
+  PrinterInfoLock lock = TryEnsurePrinterInfo();
+  // Compare major version.
+  if (lock->mCUPSMajor > aCUPSMajor) {
+    return true;
+  }
+  if (lock->mCUPSMajor < aCUPSMajor) {
+    return false;
+  }
+
+  // Compare minor version.
+  if (lock->mCUPSMinor > aCUPSMinor) {
+    return true;
+  }
+  if (lock->mCUPSMinor < aCUPSMinor) {
+    return false;
+  }
+
+  // Compare patch.
+  return aCUPSPatch <= lock->mCUPSPatch;
+}
+
+http_t* nsPrinterCUPS::Connection::GetConnection(cups_dest_t* aDest) {
+  if (mWasInited) {
+    return mConnection;
+  }
+  mWasInited = true;
+
+  // blocking call
+  http_t* const connection = mShim.cupsConnectDest(aDest, CUPS_DEST_FLAGS_NONE,
+                                                   /* timeout(ms) */ 5000,
+                                                   /* cancel */ nullptr,
+                                                   /* resource */ nullptr,
+                                                   /* resourcesize */ 0,
+                                                   /* callback */ nullptr,
+                                                   /* user_data */ nullptr);
+  if (connection) {
+    mConnection = connection;
+  }
+  return mConnection;
+}
+
+nsPrinterCUPS::Connection::~Connection() {
+  if (mWasInited && mConnection) {
+    mShim.httpClose(mConnection);
+  }
+}
+
+PrintSettingsInitializer nsPrinterCUPS::DefaultSettings(
+    Connection& aConnection) const {
+  nsString printerName;
+  GetPrinterName(printerName);
+  PrinterInfoLock lock = TryEnsurePrinterInfo();
+
+  cups_size_t media;
+
+  bool hasDefaultMedia = false;
+// cupsGetDestMediaDefault appears to return more accurate defaults on macOS,
+// and the IPP attribute appears to return more accurate defaults on Linux.
+#ifdef XP_MACOSX
+  hasDefaultMedia = mShim.cupsGetDestMediaDefault(
+      CUPS_HTTP_DEFAULT, lock->mPrinter, lock->mPrinterInfo,
+      CUPS_MEDIA_FLAGS_DEFAULT, &media);
+#else
+  {
+    ipp_attribute_t* defaultMediaIPP =
+        mShim.cupsFindDestDefault
+            ? mShim.cupsFindDestDefault(CUPS_HTTP_DEFAULT, lock->mPrinter,
+                                        lock->mPrinterInfo, "media")
+            : nullptr;
+
+    const char* defaultMediaName =
+        defaultMediaIPP ? mShim.ippGetString(defaultMediaIPP, 0, nullptr)
+                        : nullptr;
+
+    hasDefaultMedia = defaultMediaName &&
+                      mShim.cupsGetDestMediaByName(
+                          CUPS_HTTP_DEFAULT, lock->mPrinter, lock->mPrinterInfo,
+                          defaultMediaName, CUPS_MEDIA_FLAGS_DEFAULT, &media);
+  }
+#endif
+
+  if (!hasDefaultMedia) {
+    return PrintSettingsInitializer{
+        std::move(printerName),
+        PaperInfo(),
+        SupportsColor(),
+    };
+  }
+
+  // Check if this is a localized fallback paper size, in which case we can
+  // avoid using the CUPS localization methods.
+  const gfx::SizeDouble sizeDouble{
+      media.width * kPointsPerHundredthMillimeter,
+      media.length * kPointsPerHundredthMillimeter};
+  if (const PaperInfo* const paperInfo = FindCommonPaperSize(sizeDouble)) {
+    return PrintSettingsInitializer{
+        std::move(printerName),
+        MakePaperInfo(paperInfo->mName, media),
+        SupportsColor(),
+    };
+  }
+
+  http_t* const connection = aConnection.GetConnection(lock->mPrinter);
+  // XXX Do we actually have the guarantee that this is utf-8?
+  NS_ConvertUTF8toUTF16 localizedName{
+      connection ? LocalizeMediaName(*connection, media) : ""};
+
+  return PrintSettingsInitializer{
+      std::move(printerName),
+      MakePaperInfo(localizedName, media),
+      SupportsColor(),
+  };
+}
+
+nsTArray<mozilla::PaperInfo> nsPrinterCUPS::PaperList(
+    Connection& aConnection) const {
+  PrinterInfoLock lock = mPrinterInfoMutex.Lock();
+  http_t* const connection = aConnection.GetConnection(lock->mPrinter);
+  TryEnsurePrinterInfo(lock, connection);
+
+  if (!lock->mPrinterInfo) {
+    return {};
+  }
+
+  const int paperCount = mShim.cupsGetDestMediaCount
+                             ? mShim.cupsGetDestMediaCount(
+                                   connection, lock->mPrinter,
+                                   lock->mPrinterInfo, CUPS_MEDIA_FLAGS_DEFAULT)
+                             : 0;
+  nsTArray<PaperInfo> paperList;
+  nsTHashtable<nsCharPtrHashKey> paperSet(std::max(paperCount, 0));
+
+  paperList.SetCapacity(paperCount);
+  for (int i = 0; i < paperCount; ++i) {
+    cups_size_t media;
+    const int getInfoSucceeded = mShim.cupsGetDestMediaByIndex(
+        connection, lock->mPrinter, lock->mPrinterInfo, i,
+        CUPS_MEDIA_FLAGS_DEFAULT, &media);
+
+    if (!getInfoSucceeded || !paperSet.EnsureInserted(media.media)) {
+      continue;
+    }
+    // Check if this is a PWG paper size, in which case we can avoid using the
+    // CUPS localization methods.
+    const gfx::SizeDouble sizeDouble{
+        media.width * kPointsPerHundredthMillimeter,
+        media.length * kPointsPerHundredthMillimeter};
+    if (const PaperInfo* const paperInfo = FindCommonPaperSize(sizeDouble)) {
+      paperList.AppendElement(MakePaperInfo(paperInfo->mName, media));
+    } else {
+      const char* const mediaName =
+          connection ? LocalizeMediaName(*connection, media) : media.media;
+      paperList.AppendElement(
+          MakePaperInfo(NS_ConvertUTF8toUTF16(mediaName), media));
+    }
+  }
+
+  return paperList;
+}
+
+void nsPrinterCUPS::TryEnsurePrinterInfo(PrinterInfoLock& aLock,
+                                         http_t* const aConnection) const {
+  if (aLock->mPrinterInfo ||
+      (aConnection == CUPS_HTTP_DEFAULT ? aLock->mTriedInitWithDefault
+                                        : aLock->mTriedInitWithConnection)) {
+    return;
+  }
+
+  if (aConnection == CUPS_HTTP_DEFAULT) {
+    aLock->mTriedInitWithDefault = true;
+  } else {
+    aLock->mTriedInitWithConnection = true;
+  }
+
+  MOZ_ASSERT(aLock->mPrinter);
+
+  // httpGetAddress was only added in CUPS 2.0, and some systems still use
+  // CUPS 1.7.
+  if (aConnection && MOZ_LIKELY(mShim.httpGetAddress && mShim.httpAddrPort)) {
+    // This is a workaround for the CUPS Bug seen in bug 1691347.
+    // This is to avoid a null string being passed to strstr in CUPS. The path
+    // in CUPS that leads to this is as follows:
+    //
+    // In cupsCopyDestInfo, CUPS_DEST_FLAG_DEVICE is set when the connection is
+    // not null (same as CUPS_HTTP_DEFAULT), the print server is not the same
+    // as our hostname and is not path-based (starts with a '/'), or the IPP
+    // port is different than the global server IPP port.
+    //
+    // https://github.com/apple/cups/blob/c9da6f63b263faef5d50592fe8cf8056e0a58aa2/cups/dest-options.c#L718-L722
+    //
+    // In _cupsGetDestResource, CUPS fetches the IPP options "device-uri" and
+    // "printer-uri-supported". Note that IPP options are returned as null when
+    // missing.
+    //
+    // https://github.com/apple/cups/blob/23c45db76a8520fd6c3b1d9164dbe312f1ab1481/cups/dest.c#L1138-L1141
+    //
+    // If the CUPS_DEST_FLAG_DEVICE is set or the "printer-uri-supported"
+    // option is not set, CUPS checks for "._tcp" in the "device-uri" option
+    // without doing a NULL-check first.
+    //
+    // https://github.com/apple/cups/blob/23c45db76a8520fd6c3b1d9164dbe312f1ab1481/cups/dest.c#L1144
+    //
+    // If we find that those branches will be taken, don't actually fetch the
+    // CUPS data and instead just return an empty printer info.
+
+    const char* const serverNameBytes = mShim.cupsServer();
+
+    if (MOZ_LIKELY(serverNameBytes)) {
+      const nsDependentCString serverName{serverNameBytes};
+
+      // We only need enough characters to determine equality with serverName.
+      // + 2 because we need one byte for the null-character, and we also want
+      // to get more characters of the host name than the server name if
+      // possible. Otherwise, if the hostname starts with the same text as the
+      // entire server name, it would compare equal when it's not.
+      const size_t hostnameMemLength = serverName.Length() + 2;
+      auto hostnameMem = MakeUnique<char[]>(hostnameMemLength);
+
+      // We don't expect httpGetHostname to return null when a connection is
+      // passed, but it's better not to make assumptions.
+      const char* const hostnameBytes = mShim.httpGetHostname(
+          aConnection, hostnameMem.get(), hostnameMemLength);
+
+      if (MOZ_LIKELY(hostnameBytes)) {
+        const nsDependentCString hostname{hostnameBytes};
+
+        // Attempt to match the condional at
+        // https://github.com/apple/cups/blob/c9da6f63b263faef5d50592fe8cf8056e0a58aa2/cups/dest-options.c#L718
+        //
+        // To find the result of the comparison CUPS performs of
+        // `strcmp(http->hostname, cg->server)`, we use httpGetHostname to try
+        // to get the value of `http->hostname`, but this isn't quite the same.
+        // For local addresses, httpGetHostName will normalize the result to be
+        // localhost", rather than the actual value of `http->hostname`.
+        //
+        // https://github.com/apple/cups/blob/2201569857f225c9874bfae19713ffb2f4bdfdeb/cups/http-addr.c#L794-L818
+        //
+        // Because of this, if both serverName and hostname equal "localhost",
+        // then the actual hostname might be a different local address that CUPS
+        // normalized in httpGetHostName, and `http->hostname` won't be equal to
+        // `cg->server` in CUPS.
+        const bool namesMightNotMatch =
+            hostname != serverName || hostname == "localhost";
+        const bool portsDiffer =
+            mShim.httpAddrPort(mShim.httpGetAddress(aConnection)) !=
+            mShim.ippPort();
+        const bool cupsDestDeviceFlag =
+            (namesMightNotMatch && serverName[0] != '/') || portsDiffer;
+
+        // Match the conditional at
+        // https://github.com/apple/cups/blob/23c45db76a8520fd6c3b1d9164dbe312f1ab1481/cups/dest.c#L1144
+        // but if device-uri is null do not call into CUPS.
+        if ((cupsDestDeviceFlag ||
+             !FindCUPSOption(aLock, "printer-uri-supported")) &&
+            !FindCUPSOption(aLock, "device-uri")) {
+          return;
+        }
+      }
+    }
+  }
+
+  // All CUPS calls that take the printer info do null-checks internally, so we
+  // can fetch this info and only worry about the result of the later CUPS
+  // functions.
+  aLock->mPrinterInfo = mShim.cupsCopyDestInfo(aConnection, aLock->mPrinter);
+
+  // Even if we failed to fetch printer info, it is still possible we can talk
+  // to the print server and get its CUPS version.
+  FetchCUPSVersionForPrinter(mShim, aLock->mPrinter, aLock->mCUPSMajor,
+                             aLock->mCUPSMinor, aLock->mCUPSPatch);
+}
+
+void nsPrinterCUPS::ForEachExtraMonochromeSetting(
+    FunctionRef<void(const nsACString&, const nsACString&)> aCallback) {
+  nsAutoCString pref;
+  Preferences::GetCString("print.cups.monochrome.extra_settings", pref);
+  if (pref.IsEmpty()) {
+    return;
+  }
+
+  for (const auto& pair : pref.Split(',')) {
+    auto splitter = pair.Split(':');
+    auto end = splitter.end();
+
+    auto key = splitter.begin();
+    if (key == end) {
+      continue;
+    }
+
+    auto value = ++splitter.begin();
+    if (value == end) {
+      continue;
+    }
+
+    aCallback(*key, *value);
+  }
+}
diff --git a/widget/nsPrinterCUPS.h b/widget/nsPrinterCUPS.h
new file mode 100644
index 0000000000..3ecf1cb982
--- /dev/null
+++ b/widget/nsPrinterCUPS.h
@@ -0,0 +1,181 @@
+/* -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 2; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrinterCUPS_h___
+#define nsPrinterCUPS_h___
+
+#include "nsPrinterBase.h"
+#include "nsPrintSettingsImpl.h"
+#include "nsCUPSShim.h"
+#include "nsString.h"
+
+#include "mozilla/DataMutex.h"
+#include "mozilla/FunctionRef.h"
+#include "mozilla/RecursiveMutex.h"
+
+/**
+ * @brief Interface to help implementing nsIPrinter using a CUPS printer.
+ */
+class nsPrinterCUPS final : public nsPrinterBase {
+ public:
+  NS_IMETHOD GetName(nsAString& aName) override;
+  NS_IMETHOD GetSystemName(nsAString& aName) override;
+  bool SupportsDuplex() const final;
+  bool SupportsColor() const final;
+  bool SupportsMonochrome() const final;
+  bool SupportsCollation() const final;
+  PrinterInfo CreatePrinterInfo() const final;
+  MarginDouble GetMarginsForPaper(nsString aPaperId) const final {
+    MOZ_ASSERT_UNREACHABLE(
+        "The CUPS API requires us to always get the margin when fetching the "
+        "paper list so there should be no need to query it separately");
+    return {};
+  }
+
+  nsPrinterCUPS() = delete;
+
+  nsPrinterCUPS(const mozilla::CommonPaperInfoArray* aArray,
+                const nsCUPSShim& aShim, nsString aDisplayName,
+                cups_dest_t* aPrinter)
+      : nsPrinterBase(aArray),
+        mShim(aShim),
+        mDisplayName(std::move(aDisplayName)),
+        mPrinterInfoMutex(CUPSPrinterInfo{aPrinter},
+                          "nsPrinterCUPS::mPrinterInfoMutex") {}
+
+  static void ForEachExtraMonochromeSetting(
+      mozilla::FunctionRef<void(const nsACString&, const nsACString&)>);
+
+ private:
+  struct CUPSPrinterInfo {
+    explicit constexpr CUPSPrinterInfo(cups_dest_t* aPrinter)
+        : mPrinter(aPrinter) {}
+    cups_dest_t* mPrinter;
+    cups_dinfo_t* mPrinterInfo = nullptr;
+    uint64_t mCUPSMajor = 0;
+    uint64_t mCUPSMinor = 0;
+    uint64_t mCUPSPatch = 0;
+
+    // Whether we have attempted to fetch mPrinterInfo with CUPS_HTTP_DEFAULT.
+    bool mTriedInitWithDefault = false;
+    // Whether we have attempted to fetch mPrinterInfo with a connection.
+    bool mTriedInitWithConnection = false;
+    CUPSPrinterInfo() = delete;
+    CUPSPrinterInfo(const CUPSPrinterInfo&) = delete;
+    CUPSPrinterInfo(CUPSPrinterInfo&& aOther)
+        : mPrinter(aOther.mPrinter),
+          mPrinterInfo(aOther.mPrinterInfo),
+          mCUPSMajor(aOther.mCUPSMajor),
+          mCUPSMinor(aOther.mCUPSMinor),
+          mCUPSPatch(aOther.mCUPSPatch) {
+      aOther.mPrinter = nullptr;
+      aOther.mPrinterInfo = nullptr;
+    }
+  };
+
+  using PrinterInfoMutex =
+      mozilla::DataMutexBase<CUPSPrinterInfo, mozilla::RecursiveMutex>;
+
+  using PrinterInfoLock = PrinterInfoMutex::AutoLock;
+
+  ~nsPrinterCUPS();
+
+  /**
+   * Retrieves the localized name for a given media (paper).
+   * Returns nullptr if the name cannot be localized.
+   */
+  const char* LocalizeMediaName(http_t& aConnection, cups_size_t& aMedia) const;
+
+  void GetPrinterName(nsAString& aName) const;
+
+  // Little util for getting support flags using the direct CUPS names.
+  bool Supports(const char* aOption, const char* aValue) const;
+
+  // Returns support value if CUPS meets the minimum version, otherwise returns
+  // |aDefault|
+  bool IsCUPSVersionAtLeast(uint64_t aCUPSMajor, uint64_t aCUPSMinor,
+                            uint64_t aCUPSPatch) const;
+
+  const char* FindCUPSOption(PrinterInfoLock& aLock, const char* name) const {
+    const cups_dest_t* const printer = aLock->mPrinter;
+    return mShim.cupsGetOption(name, printer->num_options, printer->options);
+  }
+
+  class Connection {
+   public:
+    http_t* GetConnection(cups_dest_t* aDest);
+
+    inline explicit Connection(const nsCUPSShim& aShim) : mShim(aShim) {}
+    Connection() = delete;
+    ~Connection();
+
+   protected:
+    const nsCUPSShim& mShim;
+    http_t* mConnection = CUPS_HTTP_DEFAULT;
+    bool mWasInited = false;
+  };
+
+  PrintSettingsInitializer DefaultSettings(Connection& aConnection) const;
+  nsTArray<mozilla::PaperInfo> PaperList(Connection& aConnection) const;
+  /**
+   * Attempts to populate the CUPSPrinterInfo object.
+   * This usually works with the CUPS default connection,
+   * but has been known to require an established connection
+   * on older versions of Ubuntu (18 and below).
+   */
+  PrinterInfoLock TryEnsurePrinterInfo(
+      http_t* const aConnection = CUPS_HTTP_DEFAULT) const {
+    PrinterInfoLock lock = mPrinterInfoMutex.Lock();
+    TryEnsurePrinterInfo(lock, aConnection);
+    return lock;
+  }
+
+  /**
+   * TryEnsurePrinterInfo that uses a caller-provided PrinterInfoLock.
+   *
+   * This can be used to avoid unnecessarily redundant locking of
+   * mPrinterInfoLock when getting a connection through
+   * Connection::GetConnection and then passing that into TryEnsurePrinterInfo.
+   */
+  void TryEnsurePrinterInfo(PrinterInfoLock& aLock,
+                            http_t* const aConnection) const;
+
+  const nsCUPSShim& mShim;
+  nsString mDisplayName;
+  mutable PrinterInfoMutex mPrinterInfoMutex;
+};
+
+// There's no standard setting in Core Printing for monochrome. Or rather,
+// there is (PMSetColorMode) but it does nothing. Similarly, the relevant gtk
+// setting only works on Windows, yay.
+//
+// So on CUPS the right setting to use depends on the print driver. So we set /
+// look for a variety of driver-specific keys that are known to work across
+// printers.
+//
+// We set all the known settings, because the alternative to that is parsing ppd
+// files from the printer and find the relevant known choices that can apply,
+// and that is a lot more complex, similarly sketchy (requires the same amount
+// of driver-specific knowledge), and requires using deprecated CUPS APIs.
+#define CUPS_EACH_MONOCHROME_PRINTER_SETTING(macro_)                           \
+  macro_("ColorModel", "Gray")                    /* Generic */                \
+      macro_("BRMonoColor", "Mono")               /* Brother */                \
+      macro_("BRPrintQuality", "Black")           /* Brother */                \
+      macro_("CNIJGrayScale", "1")                /* Canon */                  \
+      macro_("CNGrayscale", "True")               /* Canon */                  \
+      macro_("INK", "MONO")                       /* Epson */                  \
+      macro_("HPColorMode", "GrayscalePrint")     /* HP */                     \
+      macro_("ColorMode", "Mono")                 /* Samsung */                \
+      macro_("PrintoutMode", "Normal.Gray")       /* Foomatic */               \
+      macro_("ProcessColorModel", "Mono")         /* Samsung */                \
+      macro_("ARCMode", "CMBW")                   /* Sharp */                  \
+      macro_("XRXColor", "BW")                    /* Xerox */                  \
+      macro_("XROutputColor", "PrintAsGrayscale") /* Xerox, bug 1676191#c32 */ \
+      macro_("SelectColor", "Grayscale")          /* Konica Minolta */         \
+      macro_("OKControl", "Gray")                 /* Oki */                    \
+      macro_("BLW", "TrueM")                      /* Lexmark */                \
+      macro_("EPRendering", "None")               /* Epson */
+
+#endif /* nsPrinterCUPS_h___ */
diff --git a/widget/nsPrinterListBase.cpp b/widget/nsPrinterListBase.cpp
new file mode 100644
index 0000000000..a362474cb5
--- /dev/null
+++ b/widget/nsPrinterListBase.cpp
@@ -0,0 +1,168 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrinterListBase.h"
+#include "PrintBackgroundTask.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/gfx/Rect.h"
+#include "mozilla/IntegerRange.h"
+#include "mozilla/intl/Localization.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/RefPtr.h"
+#include "xpcpublic.h"
+
+using namespace mozilla;
+
+using mozilla::ErrorResult;
+using mozilla::intl::Localization;
+using PrinterInfo = nsPrinterListBase::PrinterInfo;
+using MarginDouble = mozilla::gfx::MarginDouble;
+
+nsPrinterListBase::nsPrinterListBase() = default;
+nsPrinterListBase::~nsPrinterListBase() = default;
+
+NS_IMPL_CYCLE_COLLECTION(nsPrinterListBase, mPrintersPromise)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsPrinterListBase)
+  NS_INTERFACE_MAP_ENTRY(nsIPrinterList)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIPrinterList)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsPrinterListBase)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsPrinterListBase)
+
+namespace mozilla {
+
+template <>
+void ResolveOrReject(dom::Promise& aPromise, nsPrinterListBase& aList,
+                     const nsTArray<PrinterInfo>& aInfo) {
+  nsTArray<RefPtr<nsIPrinter>> printers;
+  printers.SetCapacity(aInfo.Length());
+  for (auto& info : aInfo) {
+    printers.AppendElement(aList.CreatePrinter(info));
+  }
+  aPromise.MaybeResolve(printers);
+}
+
+template <>
+void ResolveOrReject(dom::Promise& aPromise, nsPrinterListBase& aList,
+                     const Maybe<PrinterInfo>& aInfo) {
+  if (aInfo) {
+    aPromise.MaybeResolve(aList.CreatePrinter(aInfo.value()));
+  } else {
+    aPromise.MaybeRejectWithNotFoundError("Printer not found");
+  }
+}
+
+}  // namespace mozilla
+
+NS_IMETHODIMP nsPrinterListBase::GetPrinters(JSContext* aCx,
+                                             Promise** aResult) {
+  EnsureCommonPaperInfo(aCx);
+  return mozilla::AsyncPromiseAttributeGetter(*this, mPrintersPromise, aCx,
+                                              aResult, "Printers"_ns,
+                                              &nsPrinterListBase::Printers);
+}
+
+NS_IMETHODIMP nsPrinterListBase::GetPrinterByName(const nsAString& aPrinterName,
+                                                  JSContext* aCx,
+                                                  Promise** aResult) {
+  EnsureCommonPaperInfo(aCx);
+  return PrintBackgroundTaskPromise(*this, aCx, aResult, "PrinterByName"_ns,
+                                    &nsPrinterListBase::PrinterByName,
+                                    nsString{aPrinterName});
+}
+
+NS_IMETHODIMP nsPrinterListBase::GetPrinterBySystemName(
+    const nsAString& aPrinterName, JSContext* aCx, Promise** aResult) {
+  EnsureCommonPaperInfo(aCx);
+  return PrintBackgroundTaskPromise(
+      *this, aCx, aResult, "PrinterBySystemName"_ns,
+      &nsPrinterListBase::PrinterBySystemName, nsString{aPrinterName});
+}
+
+NS_IMETHODIMP nsPrinterListBase::GetNamedOrDefaultPrinter(
+    const nsAString& aPrinterName, JSContext* aCx, Promise** aResult) {
+  EnsureCommonPaperInfo(aCx);
+  return PrintBackgroundTaskPromise(
+      *this, aCx, aResult, "NamedOrDefaultPrinter"_ns,
+      &nsPrinterListBase::NamedOrDefaultPrinter, nsString{aPrinterName});
+}
+
+Maybe<PrinterInfo> nsPrinterListBase::NamedOrDefaultPrinter(
+    nsString aName) const {
+  if (Maybe<PrinterInfo> value = PrinterByName(std::move(aName))) {
+    return value;
+  }
+
+  // Since the name had to be passed by-value, we can re-use it to fetch the
+  // default printer name, potentially avoiding an extra string allocation.
+  if (NS_SUCCEEDED(SystemDefaultPrinterName(aName))) {
+    return PrinterByName(std::move(aName));
+  }
+
+  return Nothing();
+}
+
+NS_IMETHODIMP nsPrinterListBase::GetFallbackPaperList(JSContext* aCx,
+                                                      Promise** aResult) {
+  ErrorResult rv;
+  nsCOMPtr<nsIGlobalObject> global = xpc::CurrentNativeGlobal(aCx);
+  RefPtr<Promise> promise = Promise::Create(global, rv);
+  if (MOZ_UNLIKELY(rv.Failed())) {
+    *aResult = nullptr;
+    return rv.StealNSResult();
+  }
+
+  EnsureCommonPaperInfo(aCx);
+  nsTArray<RefPtr<nsPaper>> papers;
+  papers.SetCapacity(nsPaper::kNumCommonPaperSizes);
+  for (const auto& info : *mCommonPaperInfo) {
+    papers.AppendElement(MakeRefPtr<nsPaper>(info));
+  }
+
+  promise->MaybeResolve(papers);
+  promise.forget(aResult);
+  return NS_OK;
+}
+
+void nsPrinterListBase::EnsureCommonPaperInfo(JSContext* aCx) {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  if (mCommonPaperInfo) {
+    return;
+  }
+  RefPtr<CommonPaperInfoArray> localizedPaperInfo =
+      MakeRefPtr<CommonPaperInfoArray>();
+  CommonPaperInfoArray& paperArray = *localizedPaperInfo;
+  // Apply localization to the names while constructing the PaperInfo, if
+  // available (otherwise leave them as the internal keys, which are at least
+  // somewhat recognizable).
+  IgnoredErrorResult rv;
+  nsTArray<nsCString> resIds = {
+      "toolkit/printing/printUI.ftl"_ns,
+  };
+  RefPtr<Localization> l10n = Localization::Create(resIds, true);
+
+  for (auto i : IntegerRange(nsPaper::kNumCommonPaperSizes)) {
+    const CommonPaperSize& size = nsPaper::kCommonPaperSizes[i];
+    PaperInfo& info = paperArray[i];
+
+    nsAutoCString key{"printui-paper-"};
+    key.Append(size.mLocalizableNameKey);
+    nsAutoCString name;
+    l10n->FormatValueSync(key, {}, name, rv);
+
+    // Fill out the info with our PWG size and the localized name.
+    info.mId = size.mPWGName;
+    CopyUTF8toUTF16(
+        (rv.Failed() || name.IsEmpty())
+            ? static_cast<const nsCString&>(size.mLocalizableNameKey)
+            : name,
+        info.mName);
+    info.mSize = size.mSize;
+    info.mUnwriteableMargin = Some(MarginDouble{});
+  }
+  mCommonPaperInfo = std::move(localizedPaperInfo);
+}
diff --git a/widget/nsPrinterListBase.h b/widget/nsPrinterListBase.h
new file mode 100644
index 0000000000..9f922d74b5
--- /dev/null
+++ b/widget/nsPrinterListBase.h
@@ -0,0 +1,92 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrinterListBase_h__
+#define nsPrinterListBase_h__
+
+#include "nsIPrinterList.h"
+
+#include "nsCycleCollectionParticipant.h"
+#include "nsISupportsImpl.h"
+#include "nsPaper.h"
+#include "nsString.h"
+
+class nsPrinterListBase : public nsIPrinterList {
+ public:
+  using Promise = mozilla::dom::Promise;
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS(nsPrinterListBase)
+  NS_IMETHOD GetSystemDefaultPrinterName(nsAString& aName) final {
+    return SystemDefaultPrinterName(aName);
+  }
+  NS_IMETHOD GetPrinters(JSContext*, Promise**) final;
+  NS_IMETHOD GetPrinterByName(const nsAString& aPrinterName, JSContext* aCx,
+                              Promise** aResult) final;
+  NS_IMETHOD GetPrinterBySystemName(const nsAString& aPrinterName,
+                                    JSContext* aCx, Promise** aResult) final;
+  NS_IMETHOD GetNamedOrDefaultPrinter(const nsAString& aPrinterName,
+                                      JSContext* aCx, Promise** aResult) final;
+  NS_IMETHOD GetFallbackPaperList(JSContext*, Promise**) final;
+
+  struct PrinterInfo {
+    // Both windows and CUPS: The name of the printer.
+    nsString mName;
+    // CUPS only: Handle to owned cups_dest_t.
+    void* mCupsHandle = nullptr;
+  };
+
+  // Called off the main thread, collect information to create an appropriate
+  // list of printers.
+  virtual nsTArray<PrinterInfo> Printers() const = 0;
+
+  // Create an nsIPrinter object given the information we obtained from the
+  // background thread.
+  virtual RefPtr<nsIPrinter> CreatePrinter(PrinterInfo) const = 0;
+
+  mozilla::Maybe<PrinterInfo> NamedOrDefaultPrinter(nsString aName) const;
+
+  // No copy or move, we're an identity.
+  nsPrinterListBase(const nsPrinterListBase&) = delete;
+  nsPrinterListBase(nsPrinterListBase&&) = delete;
+
+ protected:
+  nsPrinterListBase();
+  virtual ~nsPrinterListBase();
+
+  // This could be implemented in terms of Printers() and then searching the
+  // returned printer info for a printer of the given name, but we expect
+  // backends to have more efficient methods of implementing this.
+  virtual mozilla::Maybe<PrinterInfo> PrinterByName(nsString aName) const = 0;
+
+  // Same as NamedPrinter, but uses the system name.
+  // Depending on whether or not there is a more efficient way to address the
+  // printer for a given backend, this may or may not be equivalent to
+  // NamedPrinter.
+  virtual mozilla::Maybe<PrinterInfo> PrinterBySystemName(
+      nsString aName) const = 0;
+
+  // This is implemented separately from the IDL interface version so that it
+  // can be made const, which allows it to be used while resolving promises.
+  virtual nsresult SystemDefaultPrinterName(nsAString&) const = 0;
+
+  // Return "paper" sizes to be supported by the Save to PDF destination;
+  // for actual printer drivers the list is retrieved from nsIPrinter.
+  nsTArray<RefPtr<nsPaper>> FallbackPaperList() const;
+
+  // Constructs mCommonPaperInfo by localizing the sizes in
+  // nsPaper::kCommonPaperSizes and creating corresponding PaperInfo.
+  void EnsureCommonPaperInfo(JSContext* aCx);
+
+  RefPtr<Promise> mPrintersPromise;
+  // PaperInfo for our fallback sizes and common size localization.
+  // This field contains the same data for every instance of this class.
+  // It's unfortunate that this needs to be a member rather than static data
+  // like nsPaper::kCommonPaperSizes, but that's because PaperInfo contains
+  // localized data, and we need a JSContext to do the localization.
+  RefPtr<const mozilla::CommonPaperInfoArray> mCommonPaperInfo;
+};
+
+#endif
diff --git a/widget/nsPrinterListCUPS.cpp b/widget/nsPrinterListCUPS.cpp
new file mode 100644
index 0000000000..2629d7626e
--- /dev/null
+++ b/widget/nsPrinterListCUPS.cpp
@@ -0,0 +1,233 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrinterListCUPS.h"
+
+#include "mozilla/IntegerRange.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/StaticPrefs_print.h"
+#include "nsCUPSShim.h"
+#include "nsPrinterCUPS.h"
+#include "nsString.h"
+#include "prenv.h"
+
+// Use a local static to initialize the CUPS shim lazily, when it's needed.
+// This is used in order to avoid a global constructor.
+static nsCUPSShim& CupsShim() {
+  static nsCUPSShim sCupsShim;
+  return sCupsShim;
+}
+
+using PrinterInfo = nsPrinterListBase::PrinterInfo;
+
+/**
+ * Retrieves a human-readable name for the printer from CUPS.
+ * https://www.cups.org/doc/cupspm.html#basic-destination-information
+ */
+static void GetDisplayNameForPrinter(const cups_dest_t& aDest,
+                                     nsAString& aName) {
+// macOS clients expect prettified printer names
+// while GTK clients expect non-prettified names.
+// If you change this, please change NamedPrinter accordingly.
+#ifdef XP_MACOSX
+  const char* displayName = CupsShim().cupsGetOption(
+      "printer-info", aDest.num_options, aDest.options);
+  if (displayName) {
+    CopyUTF8toUTF16(mozilla::MakeStringSpan(displayName), aName);
+  }
+#endif
+}
+
+NS_IMETHODIMP
+nsPrinterListCUPS::InitPrintSettingsFromPrinter(
+    const nsAString& aPrinterName, nsIPrintSettings* aPrintSettings) {
+  MOZ_ASSERT(aPrintSettings);
+
+  // Set a default file name.
+  nsAutoString filename;
+  nsresult rv = aPrintSettings->GetToFileName(filename);
+  if (NS_FAILED(rv) || filename.IsEmpty()) {
+    const char* path = PR_GetEnv("PWD");
+    if (!path) {
+      path = PR_GetEnv("HOME");
+    }
+
+    if (path) {
+      CopyUTF8toUTF16(mozilla::MakeStringSpan(path), filename);
+      filename.AppendLiteral("/mozilla.pdf");
+    } else {
+      filename.AssignLiteral("mozilla.pdf");
+    }
+
+    aPrintSettings->SetToFileName(filename);
+  }
+
+  aPrintSettings->SetIsInitializedFromPrinter(true);
+  return NS_OK;
+}
+
+static int CupsDestCallback(void* user_data, unsigned aFlags,
+                            cups_dest_t* aDest) {
+  MOZ_ASSERT(user_data);
+  auto* printerInfoList = static_cast<nsTArray<PrinterInfo>*>(user_data);
+
+  cups_dest_t* ownedDest = nullptr;
+  mozilla::DebugOnly<const int> numCopied =
+      CupsShim().cupsCopyDest(aDest, 0, &ownedDest);
+  MOZ_ASSERT(numCopied == 1);
+
+  nsString name;
+  GetDisplayNameForPrinter(*aDest, name);
+
+  printerInfoList->AppendElement(PrinterInfo{std::move(name), ownedDest});
+
+  return aFlags == CUPS_DEST_FLAGS_MORE ? 1 : 0;
+}
+
+nsTArray<PrinterInfo> nsPrinterListCUPS::Printers() const {
+  if (!CupsShim().InitOkay()) {
+    return {};
+  }
+
+  auto FreeDestsAndClear = [](nsTArray<PrinterInfo>& aArray) {
+    for (auto& info : aArray) {
+      CupsShim().cupsFreeDests(1, static_cast<cups_dest_t*>(info.mCupsHandle));
+    }
+    aArray.Clear();
+  };
+
+  nsTArray<PrinterInfo> printerInfoList;
+  // cupsGetDests2 returns list of found printers without duplicates, unlike
+  // cupsEnumDests
+  cups_dest_t* printers = nullptr;
+  const auto numPrinters = CupsShim().cupsGetDests2(nullptr, &printers);
+  if (numPrinters > 0) {
+    for (auto i : mozilla::IntegerRange(0, numPrinters)) {
+      cups_dest_t* ownedDest = nullptr;
+      mozilla::DebugOnly<const int> numCopied =
+          CupsShim().cupsCopyDest(printers + i, 0, &ownedDest);
+      MOZ_ASSERT(numCopied == 1);
+
+      nsString name;
+      GetDisplayNameForPrinter(*(printers + i), name);
+      printerInfoList.AppendElement(PrinterInfo{std::move(name), ownedDest});
+    }
+    CupsShim().cupsFreeDests(numPrinters, printers);
+    return printerInfoList;
+  }
+
+  // An error occurred - retry with CUPS_PRINTER_DISCOVERED masked out (since
+  // it looks like there are a lot of error cases for that in cupsEnumDests):
+  if (CupsShim().cupsEnumDests(
+          CUPS_DEST_FLAGS_NONE,
+          0 /* 0 timeout should be okay when masking CUPS_PRINTER_DISCOVERED */,
+          nullptr /* cancel* */, CUPS_PRINTER_LOCAL,
+          CUPS_PRINTER_FAX | CUPS_PRINTER_SCANNER | CUPS_PRINTER_DISCOVERED,
+          &CupsDestCallback, &printerInfoList)) {
+    return printerInfoList;
+  }
+
+  // Another error occurred. Maybe printerInfoList could be partially
+  // populated, so perhaps we could return it without clearing it in the hope
+  // that there are some usable dests. However, presuambly CUPS doesn't
+  // guarantee that any dests that it added are complete and safe to use when
+  // an error occurs?
+  FreeDestsAndClear(printerInfoList);
+  return {};
+}
+
+RefPtr<nsIPrinter> nsPrinterListCUPS::CreatePrinter(PrinterInfo aInfo) const {
+  return mozilla::MakeRefPtr<nsPrinterCUPS>(
+      mCommonPaperInfo, CupsShim(), std::move(aInfo.mName),
+      static_cast<cups_dest_t*>(aInfo.mCupsHandle));
+}
+
+mozilla::Maybe<PrinterInfo> nsPrinterListCUPS::PrinterByName(
+    nsString aPrinterName) const {
+  mozilla::Maybe<PrinterInfo> rv;
+  if (!CupsShim().InitOkay()) {
+    return rv;
+  }
+
+  // Will contain the printer, if found. This must be fully owned, and not a
+  // member of another array of printers.
+  cups_dest_t* printer = nullptr;
+
+#ifdef XP_MACOSX
+  // On OS X the printer name given to this function is the readable/display
+  // name and not the CUPS name, so we iterate over all the printers for now.
+  // See bug 1659807 for one approach to improve perf here.
+  {
+    nsAutoCString printerName;
+    CopyUTF16toUTF8(aPrinterName, printerName);
+    cups_dest_t* printers = nullptr;
+    const auto numPrinters = CupsShim().cupsGetDests(&printers);
+    for (auto i : mozilla::IntegerRange(0, numPrinters)) {
+      const char* const displayName = CupsShim().cupsGetOption(
+          "printer-info", printers[i].num_options, printers[i].options);
+      if (printerName == displayName) {
+        // The second arg to CupsShim().cupsCopyDest is called num_dests, but
+        // it actually copies num_dests + 1 elements.
+        CupsShim().cupsCopyDest(printers + i, 0, &printer);
+        break;
+      }
+    }
+    CupsShim().cupsFreeDests(numPrinters, printers);
+  }
+#else
+  // On GTK, we only ever show the CUPS name of printers, so we can use
+  // cupsGetNamedDest directly.
+  {
+    const auto printerName = NS_ConvertUTF16toUTF8(aPrinterName);
+    printer = CupsShim().cupsGetNamedDest(CUPS_HTTP_DEFAULT, printerName.get(),
+                                          nullptr);
+  }
+#endif
+
+  if (printer) {
+    // Since the printer name had to be passed by-value, we can move the
+    // name from that.
+    rv.emplace(PrinterInfo{std::move(aPrinterName), printer});
+  }
+  return rv;
+}
+
+mozilla::Maybe<PrinterInfo> nsPrinterListCUPS::PrinterBySystemName(
+    nsString aPrinterName) const {
+  mozilla::Maybe<PrinterInfo> rv;
+  if (!CupsShim().InitOkay()) {
+    return rv;
+  }
+
+  const auto printerName = NS_ConvertUTF16toUTF8(aPrinterName);
+  if (cups_dest_t* const printer = CupsShim().cupsGetNamedDest(
+          CUPS_HTTP_DEFAULT, printerName.get(), nullptr)) {
+    rv.emplace(PrinterInfo{std::move(aPrinterName), printer});
+  }
+  return rv;
+}
+
+nsresult nsPrinterListCUPS::SystemDefaultPrinterName(nsAString& aName) const {
+  aName.Truncate();
+
+  if (!CupsShim().InitOkay()) {
+    return NS_OK;
+  }
+
+  // Passing in nullptr for the name will return the default, if any.
+  cups_dest_t* dest =
+      CupsShim().cupsGetNamedDest(CUPS_HTTP_DEFAULT, /* name */ nullptr,
+                                  /* instance */ nullptr);
+  if (!dest) {
+    return NS_OK;
+  }
+
+  GetDisplayNameForPrinter(*dest, aName);
+  if (aName.IsEmpty()) {
+    CopyUTF8toUTF16(mozilla::MakeStringSpan(dest->name), aName);
+  }
+
+  CupsShim().cupsFreeDests(1, dest);
+  return NS_OK;
+}
diff --git a/widget/nsPrinterListCUPS.h b/widget/nsPrinterListCUPS.h
new file mode 100644
index 0000000000..77fff571c6
--- /dev/null
+++ b/widget/nsPrinterListCUPS.h
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrinterListCUPS_h__
+#define nsPrinterListCUPS_h__
+
+#include "nsPrinterListBase.h"
+#include "nsStringFwd.h"
+
+namespace mozilla {
+template <typename T>
+class Maybe;
+}  // namespace mozilla
+
+class nsPrinterListCUPS final : public nsPrinterListBase {
+  NS_IMETHOD InitPrintSettingsFromPrinter(const nsAString&,
+                                          nsIPrintSettings*) final;
+
+  nsTArray<PrinterInfo> Printers() const final;
+  RefPtr<nsIPrinter> CreatePrinter(PrinterInfo) const final;
+  mozilla::Maybe<PrinterInfo> PrinterByName(nsString aPrinterName) const final;
+  mozilla::Maybe<PrinterInfo> PrinterBySystemName(
+      nsString aPrinterName) const final;
+  nsresult SystemDefaultPrinterName(nsAString&) const final;
+
+ private:
+  ~nsPrinterListCUPS() override = default;
+};
+
+#endif
diff --git a/widget/nsTransferable.cpp b/widget/nsTransferable.cpp
new file mode 100644
index 0000000000..58a8630801
--- /dev/null
+++ b/widget/nsTransferable.cpp
@@ -0,0 +1,561 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+Notes to self:
+
+- at some point, strings will be accessible from JS, so we won't have to wrap
+   flavors in an nsISupportsCString. Until then, we're kinda stuck with
+   this crappy API of nsIArrays.
+
+*/
+
+#include "nsTransferable.h"
+#include "nsAnonymousTemporaryFile.h"
+#include "nsArray.h"
+#include "nsArrayUtils.h"
+#include "nsString.h"
+#include "nsReadableUtils.h"
+#include "nsTArray.h"
+#include "nsIFormatConverter.h"
+#include "nsIContentPolicy.h"
+#include "nsCOMPtr.h"
+#include "nsXPCOM.h"
+#include "nsISupportsPrimitives.h"
+#include "nsPrimitiveHelpers.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsDirectoryService.h"
+#include "nsCRT.h"
+#include "nsNetUtil.h"
+#include "nsILoadContext.h"
+#include "nsXULAppAPI.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/UniquePtr.h"
+
+using namespace mozilla;
+
+NS_IMPL_ISUPPORTS(nsTransferable, nsITransferable)
+
+DataStruct::DataStruct(DataStruct&& aRHS)
+    : mData(aRHS.mData.forget()),
+      mCacheFD(aRHS.mCacheFD),
+      mFlavor(aRHS.mFlavor) {
+  aRHS.mCacheFD = nullptr;
+}
+
+//-------------------------------------------------------------------------
+DataStruct::~DataStruct() {
+  if (mCacheFD) {
+    PR_Close(mCacheFD);
+  }
+}
+
+//-------------------------------------------------------------------------
+
+void DataStruct::SetData(nsISupports* aData, bool aIsPrivateData) {
+  // Now, check to see if we consider the data to be "too large"
+  // as well as ensuring that private browsing mode is disabled.
+  // File IO is not allowed in content processes.
+  if (!aIsPrivateData && XRE_IsParentProcess()) {
+    void* data = nullptr;
+    uint32_t dataLen = 0;
+    nsPrimitiveHelpers::CreateDataFromPrimitive(mFlavor, aData, &data,
+                                                &dataLen);
+
+    if (dataLen > kLargeDatasetSize) {
+      // Too large, cache it to disk instead of memory.
+      if (NS_SUCCEEDED(WriteCache(data, dataLen))) {
+        free(data);
+        // Clear previously set small data.
+        mData = nullptr;
+        return;
+      }
+
+      NS_WARNING("Oh no, couldn't write data to the cache file");
+    }
+
+    free(data);
+  }
+
+  if (mCacheFD) {
+    // Clear previously set big data.
+    PR_Close(mCacheFD);
+    mCacheFD = nullptr;
+  }
+
+  mData = aData;
+}
+
+//-------------------------------------------------------------------------
+void DataStruct::GetData(nsISupports** aData) {
+  // check here to see if the data is cached on disk
+  if (mCacheFD) {
+    // if so, read it in and pass it back
+    // ReadCache creates memory and copies the data into it.
+    if (NS_SUCCEEDED(ReadCache(aData))) {
+      return;
+    }
+
+    // oh shit, something went horribly wrong here.
+    NS_WARNING("Oh no, couldn't read data in from the cache file");
+    *aData = nullptr;
+    PR_Close(mCacheFD);
+    mCacheFD = nullptr;
+    return;
+  }
+
+  nsCOMPtr<nsISupports> data = mData;
+  data.forget(aData);
+}
+
+//-------------------------------------------------------------------------
+void DataStruct::ClearData() {
+  if (mCacheFD) {
+    PR_Close(mCacheFD);
+  }
+  mData = nullptr;
+}
+
+//-------------------------------------------------------------------------
+nsresult DataStruct::WriteCache(void* aData, uint32_t aDataLen) {
+  MOZ_ASSERT(aData && aDataLen);
+  MOZ_ASSERT(aDataLen <= uint32_t(std::numeric_limits<int32_t>::max()),
+             "too large size for PR_Write");
+
+  nsresult rv;
+  if (!mCacheFD) {
+    rv = NS_OpenAnonymousTemporaryFile(&mCacheFD);
+    if (NS_FAILED(rv)) {
+      return NS_ERROR_FAILURE;
+    }
+  } else if (PR_Seek64(mCacheFD, 0, PR_SEEK_SET) == -1) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Write out the contents of the clipboard to the file.
+  int32_t written = PR_Write(mCacheFD, aData, aDataLen);
+  if (written == int32_t(aDataLen)) {
+    return NS_OK;
+  }
+
+  PR_Close(mCacheFD);
+  mCacheFD = nullptr;
+  return NS_ERROR_FAILURE;
+}
+
+//-------------------------------------------------------------------------
+nsresult DataStruct::ReadCache(nsISupports** aData) {
+  if (!mCacheFD) {
+    return NS_ERROR_FAILURE;
+  }
+
+  PRFileInfo fileInfo;
+  if (PR_GetOpenFileInfo(mCacheFD, &fileInfo) != PR_SUCCESS) {
+    return NS_ERROR_FAILURE;
+  }
+  if (PR_Seek64(mCacheFD, 0, PR_SEEK_SET) == -1) {
+    return NS_ERROR_FAILURE;
+  }
+  uint32_t fileSize = fileInfo.size;
+
+  auto data = MakeUnique<char[]>(fileSize);
+  if (!data) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  uint32_t actual = PR_Read(mCacheFD, data.get(), fileSize);
+  if (actual != fileSize) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsPrimitiveHelpers::CreatePrimitiveForData(mFlavor, data.get(), fileSize,
+                                             aData);
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+//
+// Transferable constructor
+//
+//-------------------------------------------------------------------------
+nsTransferable::nsTransferable()
+    : mPrivateData(false),
+      mContentPolicyType(nsIContentPolicy::TYPE_OTHER)
+#ifdef DEBUG
+      ,
+      mInitialized(false)
+#endif
+{
+}
+
+//-------------------------------------------------------------------------
+//
+// Transferable destructor
+//
+//-------------------------------------------------------------------------
+nsTransferable::~nsTransferable() = default;
+
+NS_IMETHODIMP
+nsTransferable::Init(nsILoadContext* aContext) {
+  MOZ_ASSERT(!mInitialized);
+
+  if (aContext) {
+    mPrivateData = aContext->UsePrivateBrowsing();
+  } else {
+    // without aContext here to provide PrivateBrowsing information, we defer to
+    // the active configured setting
+    mPrivateData = StaticPrefs::browser_privatebrowsing_autostart();
+  }
+#ifdef DEBUG
+  mInitialized = true;
+#endif
+  return NS_OK;
+}
+
+//
+// GetTransferDataFlavors
+//
+// Returns a copy of the internal list of flavors. This does NOT take into
+// account any converter that may be registered.
+//
+void nsTransferable::GetTransferDataFlavors(nsTArray<nsCString>& aFlavors) {
+  MOZ_ASSERT(mInitialized);
+
+  for (size_t i = 0; i < mDataArray.Length(); ++i) {
+    DataStruct& data = mDataArray.ElementAt(i);
+    aFlavors.AppendElement(data.GetFlavor());
+  }
+}
+
+Maybe<size_t> nsTransferable::FindDataFlavor(const char* aFlavor) {
+  nsDependentCString flavor(aFlavor);
+
+  for (size_t i = 0; i < mDataArray.Length(); ++i) {
+    if (mDataArray[i].GetFlavor().Equals(flavor)) {
+      return Some(i);
+    }
+  }
+
+  return Nothing();
+}
+
+//
+// GetTransferData
+//
+// Returns the data of the requested flavor, obtained from either having the
+// data on hand or using a converter to get it. The data is wrapped in a
+// nsISupports primitive so that it is accessible from JS.
+//
+NS_IMETHODIMP
+nsTransferable::GetTransferData(const char* aFlavor, nsISupports** aData) {
+  MOZ_ASSERT(mInitialized);
+
+  *aData = nullptr;
+
+  nsresult rv = NS_OK;
+
+  // First look and see if the data is present in one of the intrinsic flavors.
+  if (Maybe<size_t> index = FindDataFlavor(aFlavor)) {
+    nsCOMPtr<nsISupports> dataBytes;
+    mDataArray[index.value()].GetData(getter_AddRefs(dataBytes));
+
+    // Do we have a (lazy) data provider?
+    if (nsCOMPtr<nsIFlavorDataProvider> dataProvider =
+            do_QueryInterface(dataBytes)) {
+      rv =
+          dataProvider->GetFlavorData(this, aFlavor, getter_AddRefs(dataBytes));
+      if (NS_FAILED(rv)) {
+        dataBytes = nullptr;
+        // The provider failed, fall into the converter code below.
+      }
+    }
+
+    if (dataBytes) {
+      dataBytes.forget(aData);
+      return NS_OK;
+    }
+
+    // Empty data
+  }
+
+  // If not, try using a format converter to get the requested flavor.
+  if (mFormatConv) {
+    for (size_t i = 0; i < mDataArray.Length(); ++i) {
+      DataStruct& data = mDataArray.ElementAt(i);
+      bool canConvert = false;
+      mFormatConv->CanConvert(data.GetFlavor().get(), aFlavor, &canConvert);
+      if (canConvert) {
+        nsCOMPtr<nsISupports> dataBytes;
+        data.GetData(getter_AddRefs(dataBytes));
+
+        // Do we have a (lazy) data provider?
+        if (nsCOMPtr<nsIFlavorDataProvider> dataProvider =
+                do_QueryInterface(dataBytes)) {
+          rv = dataProvider->GetFlavorData(this, aFlavor,
+                                           getter_AddRefs(dataBytes));
+          if (NS_FAILED(rv)) {
+            // Give up.
+            return rv;
+          }
+        }
+
+        return mFormatConv->Convert(data.GetFlavor().get(), dataBytes, aFlavor,
+                                    aData);
+      }
+    }
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+//
+// GetAnyTransferData
+//
+// Returns the data of the first flavor found. Caller is responsible for
+// deleting the flavor string.
+//
+NS_IMETHODIMP
+nsTransferable::GetAnyTransferData(nsACString& aFlavor, nsISupports** aData) {
+  MOZ_ASSERT(mInitialized);
+
+  for (size_t i = 0; i < mDataArray.Length(); ++i) {
+    DataStruct& data = mDataArray.ElementAt(i);
+    if (data.IsDataAvailable()) {
+      aFlavor.Assign(data.GetFlavor());
+      data.GetData(aData);
+      return NS_OK;
+    }
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+//
+// SetTransferData
+//
+//
+//
+NS_IMETHODIMP
+nsTransferable::SetTransferData(const char* aFlavor, nsISupports* aData) {
+  MOZ_ASSERT(mInitialized);
+
+  // first check our intrinsic flavors to see if one has been registered.
+  if (Maybe<size_t> index = FindDataFlavor(aFlavor)) {
+    DataStruct& data = mDataArray.ElementAt(index.value());
+    data.SetData(aData, mPrivateData);
+    return NS_OK;
+  }
+
+  // if not, try using a format converter to find a flavor to put the data in
+  if (mFormatConv) {
+    for (size_t i = 0; i < mDataArray.Length(); ++i) {
+      DataStruct& data = mDataArray.ElementAt(i);
+      bool canConvert = false;
+      mFormatConv->CanConvert(aFlavor, data.GetFlavor().get(), &canConvert);
+
+      if (canConvert) {
+        nsCOMPtr<nsISupports> ConvertedData;
+        mFormatConv->Convert(aFlavor, aData, data.GetFlavor().get(),
+                             getter_AddRefs(ConvertedData));
+        data.SetData(ConvertedData, mPrivateData);
+        return NS_OK;
+      }
+    }
+  }
+
+  // Can't set data neither directly nor through converter. Just add this flavor
+  // and try again
+  if (NS_SUCCEEDED(AddDataFlavor(aFlavor))) {
+    return SetTransferData(aFlavor, aData);
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsTransferable::ClearAllData() {
+  for (auto& entry : mDataArray) {
+    entry.ClearData();
+  }
+  return NS_OK;
+}
+
+//
+// AddDataFlavor
+//
+// Adds a data flavor to our list with no data. Error if it already exists.
+//
+NS_IMETHODIMP
+nsTransferable::AddDataFlavor(const char* aDataFlavor) {
+  MOZ_ASSERT(mInitialized);
+
+  if (FindDataFlavor(aDataFlavor).isSome()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Create a new "slot" for the data
+  mDataArray.AppendElement(DataStruct(aDataFlavor));
+  return NS_OK;
+}
+
+//
+// RemoveDataFlavor
+//
+// Removes a data flavor (and causes the data to be destroyed). Error if
+// the requested flavor is not present.
+//
+NS_IMETHODIMP
+nsTransferable::RemoveDataFlavor(const char* aDataFlavor) {
+  MOZ_ASSERT(mInitialized);
+
+  if (Maybe<size_t> index = FindDataFlavor(aDataFlavor)) {
+    mDataArray.RemoveElementAt(index.value());
+    return NS_OK;
+  }
+
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsTransferable::SetConverter(nsIFormatConverter* aConverter) {
+  MOZ_ASSERT(mInitialized);
+
+  mFormatConv = aConverter;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsTransferable::GetConverter(nsIFormatConverter** aConverter) {
+  MOZ_ASSERT(mInitialized);
+
+  nsCOMPtr<nsIFormatConverter> converter = mFormatConv;
+  converter.forget(aConverter);
+  return NS_OK;
+}
+
+//
+// FlavorsTransferableCanImport
+//
+// Computes a list of flavors that the transferable can accept into it, either
+// through intrinsic knowledge or input data converters.
+//
+NS_IMETHODIMP
+nsTransferable::FlavorsTransferableCanImport(nsTArray<nsCString>& aFlavors) {
+  MOZ_ASSERT(mInitialized);
+
+  // Get the flavor list, and on to the end of it, append the list of flavors we
+  // can also get to through a converter. This is so that we can just walk the
+  // list in one go, looking for the desired flavor.
+  GetTransferDataFlavors(aFlavors);
+
+  if (mFormatConv) {
+    nsTArray<nsCString> convertedList;
+    mFormatConv->GetInputDataFlavors(convertedList);
+
+    for (uint32_t i = 0; i < convertedList.Length(); ++i) {
+      nsCString& flavorStr = convertedList[i];
+
+      // Don't append if already in intrinsic list
+      if (!aFlavors.Contains(flavorStr)) {
+        aFlavors.AppendElement(flavorStr);
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+//
+// FlavorsTransferableCanExport
+//
+// Computes a list of flavors that the transferable can export, either through
+// intrinsic knowledge or output data converters.
+//
+NS_IMETHODIMP
+nsTransferable::FlavorsTransferableCanExport(nsTArray<nsCString>& aFlavors) {
+  MOZ_ASSERT(mInitialized);
+
+  // Get the flavor list, and on to the end of it, append the list of flavors we
+  // can also get to through a converter. This is so that we can just walk the
+  // list in one go, looking for the desired flavor.
+  GetTransferDataFlavors(aFlavors);
+
+  if (mFormatConv) {
+    nsTArray<nsCString> convertedList;
+    mFormatConv->GetOutputDataFlavors(convertedList);
+
+    for (uint32_t i = 0; i < convertedList.Length(); ++i) {
+      nsCString& flavorStr = convertedList[i];
+
+      // Don't append if already in intrinsic list
+      if (!aFlavors.Contains(flavorStr)) {
+        aFlavors.AppendElement(flavorStr);
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+bool nsTransferable::GetIsPrivateData() {
+  MOZ_ASSERT(mInitialized);
+
+  return mPrivateData;
+}
+
+void nsTransferable::SetIsPrivateData(bool aIsPrivateData) {
+  MOZ_ASSERT(mInitialized);
+
+  mPrivateData = aIsPrivateData;
+}
+
+nsIPrincipal* nsTransferable::GetRequestingPrincipal() {
+  MOZ_ASSERT(mInitialized);
+
+  return mRequestingPrincipal;
+}
+
+void nsTransferable::SetRequestingPrincipal(
+    nsIPrincipal* aRequestingPrincipal) {
+  MOZ_ASSERT(mInitialized);
+
+  mRequestingPrincipal = aRequestingPrincipal;
+}
+
+nsContentPolicyType nsTransferable::GetContentPolicyType() {
+  MOZ_ASSERT(mInitialized);
+
+  return mContentPolicyType;
+}
+
+void nsTransferable::SetContentPolicyType(
+    nsContentPolicyType aContentPolicyType) {
+  MOZ_ASSERT(mInitialized);
+
+  mContentPolicyType = aContentPolicyType;
+}
+
+nsICookieJarSettings* nsTransferable::GetCookieJarSettings() {
+  MOZ_ASSERT(mInitialized);
+
+  return mCookieJarSettings;
+}
+
+void nsTransferable::SetCookieJarSettings(
+    nsICookieJarSettings* aCookieJarSettings) {
+  MOZ_ASSERT(mInitialized);
+
+  mCookieJarSettings = aCookieJarSettings;
+}
+
+nsIReferrerInfo* nsTransferable::GetReferrerInfo() {
+  MOZ_ASSERT(mInitialized);
+  return mReferrerInfo;
+}
+
+void nsTransferable::SetReferrerInfo(nsIReferrerInfo* aReferrerInfo) {
+  MOZ_ASSERT(mInitialized);
+  mReferrerInfo = aReferrerInfo;
+}
diff --git a/widget/nsTransferable.h b/widget/nsTransferable.h
new file mode 100644
index 0000000000..02f2b0459c
--- /dev/null
+++ b/widget/nsTransferable.h
@@ -0,0 +1,92 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsTransferable_h__
+#define nsTransferable_h__
+
+#include "nsICookieJarSettings.h"
+#include "nsIFormatConverter.h"
+#include "nsITransferable.h"
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "nsIPrincipal.h"
+#include "nsIReferrerInfo.h"
+#include "prio.h"
+#include "mozilla/Maybe.h"
+
+class nsIMutableArray;
+
+//
+// DataStruct
+//
+// Holds a flavor (a mime type) that describes the data and the associated data.
+//
+struct DataStruct {
+  explicit DataStruct(const char* aFlavor)
+      : mCacheFD(nullptr), mFlavor(aFlavor) {}
+  DataStruct(DataStruct&& aRHS);
+  ~DataStruct();
+
+  const nsCString& GetFlavor() const { return mFlavor; }
+  void SetData(nsISupports* aData, bool aIsPrivateData);
+  void GetData(nsISupports** aData);
+  void ClearData();
+  bool IsDataAvailable() const { return mData || mCacheFD; }
+
+ protected:
+  enum {
+    // The size of data over which we write the data to disk rather than
+    // keep it around in memory.
+    kLargeDatasetSize = 1000000  // 1 million bytes
+  };
+
+  nsresult WriteCache(void* aData, uint32_t aDataLen);
+  nsresult ReadCache(nsISupports** aData);
+
+  // mData OR mCacheFD should be used, not both.
+  nsCOMPtr<nsISupports> mData;  // OWNER - some varient of primitive wrapper
+  PRFileDesc* mCacheFD;
+  const nsCString mFlavor;
+
+ private:
+  DataStruct(const DataStruct&) = delete;
+  DataStruct& operator=(const DataStruct&) = delete;
+};
+
+/**
+ * XP Transferable wrapper
+ */
+
+class nsTransferable : public nsITransferable {
+ public:
+  nsTransferable();
+
+  // nsISupports
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITRANSFERABLE
+
+ protected:
+  virtual ~nsTransferable();
+
+  // Get flavors w/out converter
+  void GetTransferDataFlavors(nsTArray<nsCString>& aFlavors);
+
+  // Find index for data with the matching flavor in mDataArray.
+  mozilla::Maybe<size_t> FindDataFlavor(const char* aFlavor);
+
+  nsTArray<DataStruct> mDataArray;
+  nsCOMPtr<nsIFormatConverter> mFormatConv;
+  bool mPrivateData;
+  nsCOMPtr<nsIPrincipal> mRequestingPrincipal;
+  nsContentPolicyType mContentPolicyType;
+  nsCOMPtr<nsICookieJarSettings> mCookieJarSettings;
+  nsCOMPtr<nsIReferrerInfo> mReferrerInfo;
+#if DEBUG
+  bool mInitialized;
+#endif
+};
+
+#endif  // nsTransferable_h__
diff --git a/widget/nsUserIdleService.cpp b/widget/nsUserIdleService.cpp
new file mode 100644
index 0000000000..f70a4bb459
--- /dev/null
+++ b/widget/nsUserIdleService.cpp
@@ -0,0 +1,900 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsError.h"
+#include "nsIAsyncShutdown.h"
+#include "nsUserIdleService.h"
+#include "nsString.h"
+#include "nsIObserverService.h"
+#include "nsDebug.h"
+#include "nsCOMArray.h"
+#include "nsXULAppAPI.h"
+#include "prinrval.h"
+#include "mozilla/Logging.h"
+#include "prtime.h"
+#include "mozilla/AppShutdown.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/Services.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/Telemetry.h"
+#include <algorithm>
+
+#ifdef MOZ_WIDGET_ANDROID
+#  include <android/log.h>
+#endif
+
+using namespace mozilla;
+
+// After the twenty four hour period expires for an idle daily, this is the
+// amount of idle time we wait for before actually firing the idle-daily
+// event.
+#define DAILY_SIGNIFICANT_IDLE_SERVICE_SEC (3 * 60)
+
+// In cases where it's been longer than twenty four hours since the last
+// idle-daily, this is the shortend amount of idle time we wait for before
+// firing the idle-daily event.
+#define DAILY_SHORTENED_IDLE_SERVICE_SEC 60
+
+// Pref for last time (seconds since epoch) daily notification was sent.
+#define PREF_LAST_DAILY "idle.lastDailyNotification"
+
+// Number of seconds in a day.
+#define SECONDS_PER_DAY 86400
+
+static LazyLogModule sLog("idleService");
+
+#define LOG_TAG "GeckoIdleService"
+#define LOG_LEVEL ANDROID_LOG_DEBUG
+
+// Use this to find previously added observers in our array:
+class IdleListenerComparator {
+ public:
+  bool Equals(IdleListener a, IdleListener b) const {
+    return (a.observer == b.observer) && (a.reqIdleTime == b.reqIdleTime);
+  }
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsUserIdleServiceDaily
+
+NS_IMPL_ISUPPORTS(nsUserIdleServiceDaily, nsIObserver, nsISupportsWeakReference)
+
+NS_IMETHODIMP
+nsUserIdleServiceDaily::Observe(nsISupports*, const char* aTopic,
+                                const char16_t*) {
+  auto shutdownInProgress =
+      AppShutdown::IsInOrBeyond(ShutdownPhase::AppShutdownConfirmed);
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("nsUserIdleServiceDaily: Observe '%s' (%d)", aTopic,
+           shutdownInProgress));
+
+  if (shutdownInProgress || strcmp(aTopic, OBSERVER_TOPIC_ACTIVE) == 0) {
+    return NS_OK;
+  }
+  MOZ_ASSERT(strcmp(aTopic, OBSERVER_TOPIC_IDLE) == 0);
+
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("nsUserIdleServiceDaily: Notifying idle-daily observers"));
+#ifdef MOZ_WIDGET_ANDROID
+  __android_log_print(LOG_LEVEL, LOG_TAG, "Notifying idle-daily observers");
+#endif
+
+  // Send the idle-daily observer event
+  nsCOMPtr<nsIObserverService> observerService =
+      mozilla::services::GetObserverService();
+  NS_ENSURE_STATE(observerService);
+  (void)observerService->NotifyObservers(nullptr, OBSERVER_TOPIC_IDLE_DAILY,
+                                         nullptr);
+
+  // Notify the category observers.
+  nsCOMArray<nsIObserver> entries;
+  mCategoryObservers.GetEntries(entries);
+  for (int32_t i = 0; i < entries.Count(); ++i) {
+    (void)entries[i]->Observe(nullptr, OBSERVER_TOPIC_IDLE_DAILY, nullptr);
+  }
+
+  // Stop observing idle for today.
+  (void)mIdleService->RemoveIdleObserver(this, mIdleDailyTriggerWait);
+
+  // Set the last idle-daily time pref.
+  int32_t nowSec = static_cast<int32_t>(PR_Now() / PR_USEC_PER_SEC);
+  Preferences::SetInt(PREF_LAST_DAILY, nowSec);
+
+  // Force that to be stored so we don't retrigger twice a day under
+  // any circumstances.
+  nsIPrefService* prefs = Preferences::GetService();
+  if (prefs) {
+    prefs->SavePrefFile(nullptr);
+  }
+
+  MOZ_LOG(
+      sLog, LogLevel::Debug,
+      ("nsUserIdleServiceDaily: Storing last idle time as %d sec.", nowSec));
+#ifdef MOZ_WIDGET_ANDROID
+  __android_log_print(LOG_LEVEL, LOG_TAG, "Storing last idle time as %d",
+                      nowSec);
+#endif
+
+  // Note the moment we expect to get the next timer callback
+  mExpectedTriggerTime =
+      PR_Now() + ((PRTime)SECONDS_PER_DAY * (PRTime)PR_USEC_PER_SEC);
+
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("nsUserIdleServiceDaily: Restarting daily timer"));
+
+  // Start timer for the next check in one day.
+  (void)mTimer->InitWithNamedFuncCallback(
+      DailyCallback, this, SECONDS_PER_DAY * PR_MSEC_PER_SEC,
+      nsITimer::TYPE_ONE_SHOT, "nsUserIdleServiceDaily::Observe");
+
+  return NS_OK;
+}
+
+nsUserIdleServiceDaily::nsUserIdleServiceDaily(nsIUserIdleService* aIdleService)
+    : mIdleService(aIdleService),
+      mTimer(NS_NewTimer()),
+      mCategoryObservers(OBSERVER_TOPIC_IDLE_DAILY),
+      mExpectedTriggerTime(0),
+      mIdleDailyTriggerWait(DAILY_SIGNIFICANT_IDLE_SERVICE_SEC) {}
+
+void nsUserIdleServiceDaily::Init() {
+  // First check the time of the last idle-daily event notification. If it
+  // has been 24 hours or higher, or if we have never sent an idle-daily,
+  // get ready to send an idle-daily event. Otherwise set a timer targeted
+  // at 24 hours past the last idle-daily we sent.
+
+  int32_t lastDaily = Preferences::GetInt(PREF_LAST_DAILY, 0);
+  // Setting the pref to -1 allows to disable idle-daily, and it's particularly
+  // useful in tests. Normally there should be no need for the user to set
+  // this value.
+  if (lastDaily == -1) {
+    MOZ_LOG(sLog, LogLevel::Debug,
+            ("nsUserIdleServiceDaily: Init: disabled idle-daily"));
+    return;
+  }
+
+  int32_t nowSec = static_cast<int32_t>(PR_Now() / PR_USEC_PER_SEC);
+  if (lastDaily < 0 || lastDaily > nowSec) {
+    // The time is bogus, use default.
+    lastDaily = 0;
+  }
+  int32_t secondsSinceLastDaily = nowSec - lastDaily;
+
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("nsUserIdleServiceDaily: Init: seconds since last daily: %d",
+           secondsSinceLastDaily));
+
+  // If it has been twenty four hours or more or if we have never sent an
+  // idle-daily event get ready to send it during the next idle period.
+  if (secondsSinceLastDaily > SECONDS_PER_DAY) {
+    // Check for a "long wait", e.g. 48-hours or more.
+    bool hasBeenLongWait =
+        (lastDaily && (secondsSinceLastDaily > (SECONDS_PER_DAY * 2)));
+
+    MOZ_LOG(
+        sLog, LogLevel::Debug,
+        ("nsUserIdleServiceDaily: has been long wait? %d", hasBeenLongWait));
+
+    // StageIdleDaily sets up a wait for the user to become idle and then
+    // sends the idle-daily event.
+    StageIdleDaily(hasBeenLongWait);
+  } else {
+    MOZ_LOG(sLog, LogLevel::Debug,
+            ("nsUserIdleServiceDaily: Setting timer a day from now"));
+#ifdef MOZ_WIDGET_ANDROID
+    __android_log_print(LOG_LEVEL, LOG_TAG, "Setting timer a day from now");
+#endif
+
+    // According to our last idle-daily pref, the last idle-daily was fired
+    // less then 24 hours ago. Set a wait for the amount of time remaining.
+    int32_t milliSecLeftUntilDaily =
+        (SECONDS_PER_DAY - secondsSinceLastDaily) * PR_MSEC_PER_SEC;
+
+    MOZ_LOG(sLog, LogLevel::Debug,
+            ("nsUserIdleServiceDaily: Seconds till next timeout: %d",
+             (SECONDS_PER_DAY - secondsSinceLastDaily)));
+
+    // Mark the time at which we expect this to fire. On systems with faulty
+    // timers, we need to be able to cross check that the timer fired at the
+    // expected time.
+    mExpectedTriggerTime =
+        PR_Now() + (milliSecLeftUntilDaily * PR_USEC_PER_MSEC);
+
+    (void)mTimer->InitWithNamedFuncCallback(
+        DailyCallback, this, milliSecLeftUntilDaily, nsITimer::TYPE_ONE_SHOT,
+        "nsUserIdleServiceDaily::Init");
+  }
+}
+
+nsUserIdleServiceDaily::~nsUserIdleServiceDaily() {
+  if (mTimer) {
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
+}
+
+void nsUserIdleServiceDaily::StageIdleDaily(bool aHasBeenLongWait) {
+  NS_ASSERTION(mIdleService, "No idle service available?");
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("nsUserIdleServiceDaily: Registering Idle observer callback "
+           "(short wait requested? %d)",
+           aHasBeenLongWait));
+#ifdef MOZ_WIDGET_ANDROID
+  __android_log_print(LOG_LEVEL, LOG_TAG, "Registering Idle observer callback");
+#endif
+  mIdleDailyTriggerWait =
+      (aHasBeenLongWait ? DAILY_SHORTENED_IDLE_SERVICE_SEC
+                        : DAILY_SIGNIFICANT_IDLE_SERVICE_SEC);
+  (void)mIdleService->AddIdleObserver(this, mIdleDailyTriggerWait);
+}
+
+// static
+void nsUserIdleServiceDaily::DailyCallback(nsITimer* aTimer, void* aClosure) {
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("nsUserIdleServiceDaily: DailyCallback running"));
+#ifdef MOZ_WIDGET_ANDROID
+  __android_log_print(LOG_LEVEL, LOG_TAG, "DailyCallback running");
+#endif
+
+  nsUserIdleServiceDaily* self = static_cast<nsUserIdleServiceDaily*>(aClosure);
+
+  // Check to be sure the timer didn't fire early. This currently only
+  // happens on android.
+  PRTime now = PR_Now();
+  if (self->mExpectedTriggerTime && now < self->mExpectedTriggerTime) {
+    // Timer returned early, reschedule to the appropriate time.
+    PRTime delayTime = self->mExpectedTriggerTime - now;
+
+    // Add 10 ms to ensure we don't undershoot, and never get a "0" timer.
+    delayTime += 10 * PR_USEC_PER_MSEC;
+
+    MOZ_LOG(sLog, LogLevel::Debug,
+            ("nsUserIdleServiceDaily: DailyCallback resetting timer to %" PRId64
+             " msec",
+             delayTime / PR_USEC_PER_MSEC));
+#ifdef MOZ_WIDGET_ANDROID
+    __android_log_print(LOG_LEVEL, LOG_TAG,
+                        "DailyCallback resetting timer to %" PRId64 " msec",
+                        delayTime / PR_USEC_PER_MSEC);
+#endif
+
+    (void)self->mTimer->InitWithNamedFuncCallback(
+        DailyCallback, self, delayTime / PR_USEC_PER_MSEC,
+        nsITimer::TYPE_ONE_SHOT, "nsUserIdleServiceDaily::DailyCallback");
+    return;
+  }
+
+  // Register for a short term wait for idle event. When this fires we fire
+  // our idle-daily event.
+  self->StageIdleDaily(false);
+}
+
+/**
+ * The idle services goal is to notify subscribers when a certain time has
+ * passed since the last user interaction with the system.
+ *
+ * On some platforms this is defined as the last time user events reached this
+ * application, on other platforms it is a system wide thing - the preferred
+ * implementation is to use the system idle time, rather than the application
+ * idle time, as the things depending on the idle service are likely to use
+ * significant resources (network, disk, memory, cpu, etc.).
+ *
+ * When the idle service needs to use the system wide idle timer, it typically
+ * needs to poll the idle time value by the means of a timer.  It needs to
+ * poll fast when it is in active idle mode (when it has a listener in the idle
+ * mode) as it needs to detect if the user is active in other applications.
+ *
+ * When the service is waiting for the first listener to become idle, or when
+ * it is only monitoring application idle time, it only needs to have the timer
+ * expire at the time the next listener goes idle.
+ *
+ * The core state of the service is determined by:
+ *
+ * - A list of listeners.
+ *
+ * - A boolean that tells if any listeners are in idle mode.
+ *
+ * - A delta value that indicates when, measured from the last non-idle time,
+ *   the next listener should switch to idle mode.
+ *
+ * - An absolute time of the last time idle mode was detected (this is used to
+ *   judge if we have been out of idle mode since the last invocation of the
+ *   service.
+ *
+ * There are four entry points into the system:
+ *
+ * - A new listener is registered.
+ *
+ * - An existing listener is deregistered.
+ *
+ * - User interaction is detected.
+ *
+ * - The timer expires.
+ *
+ * When a new listener is added its idle timeout, is compared with the next idle
+ * timeout, and if lower, that time is stored as the new timeout, and the timer
+ * is reconfigured to ensure a timeout around the time the new listener should
+ * timeout.
+ *
+ * If the next idle time is above the idle time requested by the new listener
+ * it won't be informed until the timer expires, this is to avoid recursive
+ * behavior and to simplify the code.  In this case the timer will be set to
+ * about 10 ms.
+ *
+ * When an existing listener is deregistered, it is just removed from the list
+ * of active listeners, we don't stop the timer, we just let it expire.
+ *
+ * When user interaction is detected, either because it was directly detected or
+ * because we polled the system timer and found it to be unexpected low, then we
+ * check the flag that tells us if any listeners are in idle mode, if there are
+ * they are removed from idle mode and told so, and we reset our state
+ * caculating the next timeout and restart the timer if needed.
+ *
+ * ---- Build in logic
+ *
+ * In order to avoid restarting the timer endlessly, the timer function has
+ * logic that will only restart the timer, if the requested timeout is before
+ * the current timeout.
+ *
+ */
+
+////////////////////////////////////////////////////////////////////////////////
+//// nsUserIdleService
+
+namespace {
+nsUserIdleService* gIdleService;
+}  // namespace
+
+already_AddRefed<nsUserIdleService> nsUserIdleService::GetInstance() {
+  RefPtr<nsUserIdleService> instance(gIdleService);
+  return instance.forget();
+}
+
+class UserIdleBlocker final : public nsIAsyncShutdownBlocker {
+  ~UserIdleBlocker() = default;
+
+ public:
+  explicit UserIdleBlocker() = default;
+
+  NS_IMETHOD
+  GetName(nsAString& aNameOut) override {
+    aNameOut = nsLiteralString(u"UserIdleBlocker");
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  BlockShutdown(nsIAsyncShutdownClient* aClient) override {
+    if (gIdleService) {
+      gIdleService->SetDisabledForShutdown();
+    }
+    aClient->RemoveBlocker(this);
+    return NS_OK;
+  }
+
+  NS_IMETHOD
+  GetState(nsIPropertyBag**) override { return NS_OK; }
+
+  NS_DECL_ISUPPORTS
+};
+
+NS_IMPL_ISUPPORTS(UserIdleBlocker, nsIAsyncShutdownBlocker)
+
+nsUserIdleService::nsUserIdleService()
+    : mIdleObserverCount(0),
+      mDeltaToNextIdleSwitchInS(UINT32_MAX),
+      mLastUserInteraction(TimeStamp::Now()) {
+  MOZ_ASSERT(!gIdleService);
+  gIdleService = this;
+  if (XRE_IsParentProcess()) {
+    mDailyIdle = new nsUserIdleServiceDaily(this);
+    mDailyIdle->Init();
+  }
+  nsCOMPtr<nsIAsyncShutdownService> svc = services::GetAsyncShutdownService();
+  MOZ_ASSERT(svc);
+  nsCOMPtr<nsIAsyncShutdownClient> client;
+  auto rv = svc->GetQuitApplicationGranted(getter_AddRefs(client));
+  if (NS_FAILED(rv)) {
+    // quitApplicationGranted can be undefined in some environments.
+    rv = svc->GetXpcomWillShutdown(getter_AddRefs(client));
+  }
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  client->AddBlocker(new UserIdleBlocker(),
+                     NS_LITERAL_STRING_FROM_CSTRING(__FILE__), __LINE__,
+                     u""_ns);
+}
+
+nsUserIdleService::~nsUserIdleService() {
+  if (mTimer) {
+    mTimer->Cancel();
+  }
+
+  MOZ_ASSERT(gIdleService == this);
+  gIdleService = nullptr;
+}
+
+NS_IMPL_ISUPPORTS(nsUserIdleService, nsIUserIdleService,
+                  nsIUserIdleServiceInternal)
+
+void nsUserIdleService::SetDisabledForShutdown() {
+  SetDisabled(true);
+  if (mTimer) {
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
+}
+
+NS_IMETHODIMP
+nsUserIdleService::AddIdleObserver(nsIObserver* aObserver,
+                                   uint32_t aIdleTimeInS) {
+  NS_ENSURE_ARG_POINTER(aObserver);
+  // We don't accept idle time at 0, and we can't handle idle time that are too
+  // high either - no more than ~136 years.
+  NS_ENSURE_ARG_RANGE(aIdleTimeInS, 1, (UINT32_MAX / 10) - 1);
+
+  if (profiler_thread_is_being_profiled_for_markers()) {
+    nsAutoCString timeCStr;
+    timeCStr.AppendInt(aIdleTimeInS);
+    PROFILER_MARKER_TEXT("UserIdle::AddObserver", OTHER, MarkerStack::Capture(),
+                         timeCStr);
+  }
+
+  if (XRE_IsContentProcess()) {
+    dom::ContentChild* cpc = dom::ContentChild::GetSingleton();
+    cpc->AddIdleObserver(aObserver, aIdleTimeInS);
+    return NS_OK;
+  }
+
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("idleService: Register idle observer %p for %d seconds", aObserver,
+           aIdleTimeInS));
+#ifdef MOZ_WIDGET_ANDROID
+  __android_log_print(LOG_LEVEL, LOG_TAG,
+                      "Register idle observer %p for %d seconds", aObserver,
+                      aIdleTimeInS);
+#endif
+
+  // Put the time + observer in a struct we can keep:
+  IdleListener listener(aObserver, aIdleTimeInS);
+
+  // XXX(Bug 1631371) Check if this should use a fallible operation as it
+  // pretended earlier.
+  mArrayListeners.AppendElement(listener);
+
+  // Create our timer callback if it's not there already.
+  if (!mTimer) {
+    mTimer = NS_NewTimer();
+    NS_ENSURE_TRUE(mTimer, NS_ERROR_OUT_OF_MEMORY);
+  }
+
+  // Check if the newly added observer has a smaller wait time than what we
+  // are waiting for now.
+  if (mDeltaToNextIdleSwitchInS > aIdleTimeInS) {
+    // If it is, then this is the next to move to idle (at this point we
+    // don't care if it should have switched already).
+    MOZ_LOG(
+        sLog, LogLevel::Debug,
+        ("idleService: Register: adjusting next switch from %d to %d seconds",
+         mDeltaToNextIdleSwitchInS, aIdleTimeInS));
+#ifdef MOZ_WIDGET_ANDROID
+    __android_log_print(LOG_LEVEL, LOG_TAG,
+                        "Register: adjusting next switch from %d to %d seconds",
+                        mDeltaToNextIdleSwitchInS, aIdleTimeInS);
+#endif
+
+    mDeltaToNextIdleSwitchInS = aIdleTimeInS;
+    ReconfigureTimer();
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsUserIdleService::RemoveIdleObserver(nsIObserver* aObserver,
+                                      uint32_t aTimeInS) {
+  NS_ENSURE_ARG_POINTER(aObserver);
+  NS_ENSURE_ARG(aTimeInS);
+
+  if (profiler_thread_is_being_profiled_for_markers()) {
+    nsAutoCString timeCStr;
+    timeCStr.AppendInt(aTimeInS);
+    PROFILER_MARKER_TEXT("UserIdle::RemoveObserver", OTHER,
+                         MarkerStack::Capture(), timeCStr);
+  }
+
+  if (XRE_IsContentProcess()) {
+    dom::ContentChild* cpc = dom::ContentChild::GetSingleton();
+    cpc->RemoveIdleObserver(aObserver, aTimeInS);
+    return NS_OK;
+  }
+
+  IdleListener listener(aObserver, aTimeInS);
+
+  // Find the entry and remove it, if it was the last entry, we just let the
+  // existing timer run to completion (there might be a new registration in a
+  // little while.
+  IdleListenerComparator c;
+  nsTArray<IdleListener>::index_type listenerIndex =
+      mArrayListeners.IndexOf(listener, 0, c);
+  if (listenerIndex != mArrayListeners.NoIndex) {
+    if (mArrayListeners.ElementAt(listenerIndex).isIdle) mIdleObserverCount--;
+    mArrayListeners.RemoveElementAt(listenerIndex);
+    MOZ_LOG(sLog, LogLevel::Debug,
+            ("idleService: Remove observer %p (%d seconds), %d remain idle",
+             aObserver, aTimeInS, mIdleObserverCount));
+#ifdef MOZ_WIDGET_ANDROID
+    __android_log_print(LOG_LEVEL, LOG_TAG,
+                        "Remove observer %p (%d seconds), %d remain idle",
+                        aObserver, aTimeInS, mIdleObserverCount);
+#endif
+    return NS_OK;
+  }
+
+  // If we get here, we haven't removed anything:
+  MOZ_LOG(sLog, LogLevel::Warning,
+          ("idleService: Failed to remove idle observer %p (%d seconds)",
+           aObserver, aTimeInS));
+#ifdef MOZ_WIDGET_ANDROID
+  __android_log_print(LOG_LEVEL, LOG_TAG,
+                      "Failed to remove idle observer %p (%d seconds)",
+                      aObserver, aTimeInS);
+#endif
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+nsUserIdleService::ResetIdleTimeOut(uint32_t idleDeltaInMS) {
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("idleService: Reset idle timeout (last interaction %u msec)",
+           idleDeltaInMS));
+
+  // Store the time
+  mLastUserInteraction =
+      TimeStamp::Now() - TimeDuration::FromMilliseconds(idleDeltaInMS);
+
+  // If no one is idle, then we are done, any existing timers can keep running.
+  if (mIdleObserverCount == 0) {
+    MOZ_LOG(sLog, LogLevel::Debug,
+            ("idleService: Reset idle timeout: no idle observers"));
+    return NS_OK;
+  }
+
+  // Mark all idle services as non-idle, and calculate the next idle timeout.
+  nsCOMArray<nsIObserver> notifyList;
+  mDeltaToNextIdleSwitchInS = UINT32_MAX;
+
+  // Loop through all listeners, and find any that have detected idle.
+  for (uint32_t i = 0; i < mArrayListeners.Length(); i++) {
+    IdleListener& curListener = mArrayListeners.ElementAt(i);
+
+    // If the listener was idle, then he shouldn't be any longer.
+    if (curListener.isIdle) {
+      notifyList.AppendObject(curListener.observer);
+      curListener.isIdle = false;
+    }
+
+    // Check if the listener is the next one to timeout.
+    mDeltaToNextIdleSwitchInS =
+        std::min(mDeltaToNextIdleSwitchInS, curListener.reqIdleTime);
+  }
+
+  // When we are done, then we wont have anyone idle.
+  mIdleObserverCount = 0;
+
+  // Restart the idle timer, and do so before anyone can delay us.
+  ReconfigureTimer();
+
+  int32_t numberOfPendingNotifications = notifyList.Count();
+
+  // Bail if nothing to do.
+  if (!numberOfPendingNotifications) {
+    return NS_OK;
+  }
+
+  // Now send "active" events to all, if any should have timed out already,
+  // then they will be reawaken by the timer that is already running.
+
+  // We need a text string to send with any state change events.
+  nsAutoString timeStr;
+
+  timeStr.AppendInt((int32_t)(idleDeltaInMS / PR_MSEC_PER_SEC));
+
+  // Send the "non-idle" events.
+  while (numberOfPendingNotifications--) {
+    MOZ_LOG(sLog, LogLevel::Debug,
+            ("idleService: Reset idle timeout: tell observer %p user is back",
+             notifyList[numberOfPendingNotifications]));
+#ifdef MOZ_WIDGET_ANDROID
+    __android_log_print(LOG_LEVEL, LOG_TAG,
+                        "Reset idle timeout: tell observer %p user is back",
+                        notifyList[numberOfPendingNotifications]);
+#endif
+    notifyList[numberOfPendingNotifications]->Observe(
+        this, OBSERVER_TOPIC_ACTIVE, timeStr.get());
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsUserIdleService::GetIdleTime(uint32_t* idleTime) {
+  // Check sanity of in parameter.
+  if (!idleTime) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  // Polled idle time in ms.
+  uint32_t polledIdleTimeMS;
+
+  bool polledIdleTimeIsValid = PollIdleTime(&polledIdleTimeMS);
+
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("idleService: Get idle time: polled %u msec, valid = %d",
+           polledIdleTimeMS, polledIdleTimeIsValid));
+
+  // timeSinceReset is in milliseconds.
+  TimeDuration timeSinceReset = TimeStamp::Now() - mLastUserInteraction;
+  uint32_t timeSinceResetInMS = timeSinceReset.ToMilliseconds();
+
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("idleService: Get idle time: time since reset %u msec",
+           timeSinceResetInMS));
+#ifdef MOZ_WIDGET_ANDROID
+  __android_log_print(LOG_LEVEL, LOG_TAG,
+                      "Get idle time: time since reset %u msec",
+                      timeSinceResetInMS);
+#endif
+
+  // If we did't get pulled data, return the time since last idle reset.
+  if (!polledIdleTimeIsValid) {
+    // We need to convert to ms before returning the time.
+    *idleTime = timeSinceResetInMS;
+    return NS_OK;
+  }
+
+  // Otherwise return the shortest time detected (in ms).
+  *idleTime = std::min(timeSinceResetInMS, polledIdleTimeMS);
+
+  return NS_OK;
+}
+
+bool nsUserIdleService::PollIdleTime(uint32_t* /*aIdleTime*/) {
+  // Default behavior is not to have the ability to poll an idle time.
+  return false;
+}
+
+nsresult nsUserIdleService::GetDisabled(bool* aResult) {
+  *aResult = mDisabled;
+  return NS_OK;
+}
+
+nsresult nsUserIdleService::SetDisabled(bool aDisabled) {
+  mDisabled = aDisabled;
+  return NS_OK;
+}
+
+void nsUserIdleService::StaticIdleTimerCallback(nsITimer* aTimer,
+                                                void* aClosure) {
+  static_cast<nsUserIdleService*>(aClosure)->IdleTimerCallback();
+}
+
+void nsUserIdleService::IdleTimerCallback(void) {
+  // Remember that we no longer have a timer running.
+  mCurrentlySetToTimeoutAt = TimeStamp();
+
+  // Find the last detected idle time.
+  uint32_t lastIdleTimeInMS = static_cast<uint32_t>(
+      (TimeStamp::Now() - mLastUserInteraction).ToMilliseconds());
+  // Get the current idle time.
+  uint32_t currentIdleTimeInMS;
+
+  if (NS_FAILED(GetIdleTime(&currentIdleTimeInMS))) {
+    MOZ_LOG(sLog, LogLevel::Info,
+            ("idleService: Idle timer callback: failed to get idle time"));
+#ifdef MOZ_WIDGET_ANDROID
+    __android_log_print(LOG_LEVEL, LOG_TAG,
+                        "Idle timer callback: failed to get idle time");
+#endif
+    return;
+  }
+
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("idleService: Idle timer callback: current idle time %u msec",
+           currentIdleTimeInMS));
+#ifdef MOZ_WIDGET_ANDROID
+  __android_log_print(LOG_LEVEL, LOG_TAG,
+                      "Idle timer callback: current idle time %u msec",
+                      currentIdleTimeInMS);
+#endif
+
+  // Check if we have had some user interaction we didn't handle previously
+  // we do the calculation in ms to lessen the chance for rounding errors to
+  // trigger wrong results.
+  if (lastIdleTimeInMS > currentIdleTimeInMS) {
+    // We had user activity, so handle that part first (to ensure the listeners
+    // don't risk getting an non-idle after they get a new idle indication.
+    ResetIdleTimeOut(currentIdleTimeInMS);
+
+    // NOTE: We can't bail here, as we might have something already timed out.
+  }
+
+  // Find the idle time in S.
+  uint32_t currentIdleTimeInS = currentIdleTimeInMS / PR_MSEC_PER_SEC;
+
+  // Restart timer and bail if no-one are expected to be in idle
+  if (mDeltaToNextIdleSwitchInS > currentIdleTimeInS) {
+    // If we didn't expect anyone to be idle, then just re-start the timer.
+    ReconfigureTimer();
+    return;
+  }
+
+  if (mDisabled) {
+    MOZ_LOG(sLog, LogLevel::Info,
+            ("idleService: Skipping idle callback while disabled"));
+
+    ReconfigureTimer();
+    return;
+  }
+
+  // Tell expired listeners they are expired,and find the next timeout
+  Telemetry::AutoTimer<Telemetry::IDLE_NOTIFY_IDLE_MS> timer;
+
+  // We need to initialise the time to the next idle switch.
+  mDeltaToNextIdleSwitchInS = UINT32_MAX;
+
+  // Create list of observers that should be notified.
+  nsCOMArray<nsIObserver> notifyList;
+
+  for (uint32_t i = 0; i < mArrayListeners.Length(); i++) {
+    IdleListener& curListener = mArrayListeners.ElementAt(i);
+
+    // We are only interested in items, that are not in the idle state.
+    if (!curListener.isIdle) {
+      // If they have an idle time smaller than the actual idle time.
+      if (curListener.reqIdleTime <= currentIdleTimeInS) {
+        // Then add the listener to the list of listeners that should be
+        // notified.
+        notifyList.AppendObject(curListener.observer);
+        // This listener is now idle.
+        curListener.isIdle = true;
+        // Remember we have someone idle.
+        mIdleObserverCount++;
+      } else {
+        // Listeners that are not timed out yet are candidates for timing out.
+        mDeltaToNextIdleSwitchInS =
+            std::min(mDeltaToNextIdleSwitchInS, curListener.reqIdleTime);
+      }
+    }
+  }
+
+  // Restart the timer before any notifications that could slow us down are
+  // done.
+  ReconfigureTimer();
+
+  int32_t numberOfPendingNotifications = notifyList.Count();
+
+  // Bail if nothing to do.
+  if (!numberOfPendingNotifications) {
+    MOZ_LOG(
+        sLog, LogLevel::Debug,
+        ("idleService: **** Idle timer callback: no observers to message."));
+    return;
+  }
+
+  // We need a text string to send with any state change events.
+  nsAutoString timeStr;
+  timeStr.AppendInt(currentIdleTimeInS);
+
+  // Notify all listeners that just timed out.
+  while (numberOfPendingNotifications--) {
+    MOZ_LOG(
+        sLog, LogLevel::Debug,
+        ("idleService: **** Idle timer callback: tell observer %p user is idle",
+         notifyList[numberOfPendingNotifications]));
+#ifdef MOZ_WIDGET_ANDROID
+    __android_log_print(LOG_LEVEL, LOG_TAG,
+                        "Idle timer callback: tell observer %p user is idle",
+                        notifyList[numberOfPendingNotifications]);
+#endif
+    nsAutoCString timeCStr;
+    timeCStr.AppendInt(currentIdleTimeInS);
+    AUTO_PROFILER_MARKER_TEXT("UserIdle::IdleCallback", OTHER, {}, timeCStr);
+    notifyList[numberOfPendingNotifications]->Observe(this, OBSERVER_TOPIC_IDLE,
+                                                      timeStr.get());
+  }
+}
+
+void nsUserIdleService::SetTimerExpiryIfBefore(TimeStamp aNextTimeout) {
+  TimeDuration nextTimeoutDuration = aNextTimeout - TimeStamp::Now();
+
+  MOZ_LOG(
+      sLog, LogLevel::Debug,
+      ("idleService: SetTimerExpiryIfBefore: next timeout %0.f msec from now",
+       nextTimeoutDuration.ToMilliseconds()));
+
+#ifdef MOZ_WIDGET_ANDROID
+  __android_log_print(LOG_LEVEL, LOG_TAG,
+                      "SetTimerExpiryIfBefore: next timeout %0.f msec from now",
+                      nextTimeoutDuration.ToMilliseconds());
+#endif
+
+  // Bail if we don't have a timer service.
+  if (!mTimer) {
+    return;
+  }
+
+  // If the new timeout is before the old one or we don't have a timer running,
+  // then restart the timer.
+  if (mCurrentlySetToTimeoutAt.IsNull() ||
+      mCurrentlySetToTimeoutAt > aNextTimeout) {
+    mCurrentlySetToTimeoutAt = aNextTimeout;
+
+    // Stop the current timer (it's ok to try'n stop it, even it isn't running).
+    mTimer->Cancel();
+
+    // Check that the timeout is actually in the future, otherwise make it so.
+    TimeStamp currentTime = TimeStamp::Now();
+    if (currentTime > mCurrentlySetToTimeoutAt) {
+      mCurrentlySetToTimeoutAt = currentTime;
+    }
+
+    // Add 10 ms to ensure we don't undershoot, and never get a "0" timer.
+    mCurrentlySetToTimeoutAt += TimeDuration::FromMilliseconds(10);
+
+    TimeDuration deltaTime = mCurrentlySetToTimeoutAt - currentTime;
+    MOZ_LOG(
+        sLog, LogLevel::Debug,
+        ("idleService: IdleService reset timer expiry to %0.f msec from now",
+         deltaTime.ToMilliseconds()));
+#ifdef MOZ_WIDGET_ANDROID
+    __android_log_print(LOG_LEVEL, LOG_TAG,
+                        "reset timer expiry to %0.f msec from now",
+                        deltaTime.ToMilliseconds());
+#endif
+
+    // Start the timer
+    mTimer->InitWithNamedFuncCallback(
+        StaticIdleTimerCallback, this, deltaTime.ToMilliseconds(),
+        nsITimer::TYPE_ONE_SHOT, "nsUserIdleService::SetTimerExpiryIfBefore");
+  }
+}
+
+void nsUserIdleService::ReconfigureTimer(void) {
+  // Check if either someone is idle, or someone will become idle.
+  if ((mIdleObserverCount == 0) && UINT32_MAX == mDeltaToNextIdleSwitchInS) {
+    // If not, just let any existing timers run to completion
+    // And bail out.
+    MOZ_LOG(sLog, LogLevel::Debug,
+            ("idleService: ReconfigureTimer: no idle or waiting observers"));
+#ifdef MOZ_WIDGET_ANDROID
+    __android_log_print(LOG_LEVEL, LOG_TAG,
+                        "ReconfigureTimer: no idle or waiting observers");
+#endif
+    return;
+  }
+
+  // Find the next timeout value, assuming we are not polling.
+
+  // We need to store the current time, so we don't get artifacts from the time
+  // ticking while we are processing.
+  TimeStamp curTime = TimeStamp::Now();
+
+  TimeStamp nextTimeoutAt =
+      mLastUserInteraction +
+      TimeDuration::FromSeconds(mDeltaToNextIdleSwitchInS);
+
+  TimeDuration nextTimeoutDuration = nextTimeoutAt - curTime;
+
+  MOZ_LOG(sLog, LogLevel::Debug,
+          ("idleService: next timeout %0.f msec from now",
+           nextTimeoutDuration.ToMilliseconds()));
+
+#ifdef MOZ_WIDGET_ANDROID
+  __android_log_print(LOG_LEVEL, LOG_TAG, "next timeout %0.f msec from now",
+                      nextTimeoutDuration.ToMilliseconds());
+#endif
+
+  SetTimerExpiryIfBefore(nextTimeoutAt);
+}
diff --git a/widget/nsUserIdleService.h b/widget/nsUserIdleService.h
new file mode 100644
index 0000000000..2ed35cd032
--- /dev/null
+++ b/widget/nsUserIdleService.h
@@ -0,0 +1,218 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsUserIdleService_h__
+#define nsUserIdleService_h__
+
+#include "nsIUserIdleServiceInternal.h"
+#include "nsCOMPtr.h"
+#include "nsITimer.h"
+#include "nsTArray.h"
+#include "nsIObserver.h"
+#include "nsIUserIdleService.h"
+#include "nsCategoryCache.h"
+#include "nsWeakReference.h"
+#include "mozilla/TimeStamp.h"
+
+/**
+ * Class we can use to store an observer with its associated idle time
+ * requirement and whether or not the observer thinks it's "idle".
+ */
+class IdleListener {
+ public:
+  nsCOMPtr<nsIObserver> observer;
+  uint32_t reqIdleTime;
+  bool isIdle;
+
+  IdleListener(nsIObserver* obs, uint32_t reqIT, bool aIsIdle = false)
+      : observer(obs), reqIdleTime(reqIT), isIdle(aIsIdle) {}
+  ~IdleListener() = default;
+};
+
+// This one will be declared later.
+class nsUserIdleService;
+
+/**
+ * Class to handle the daily idle timer.
+ */
+class nsUserIdleServiceDaily : public nsIObserver,
+                               public nsSupportsWeakReference {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  explicit nsUserIdleServiceDaily(nsIUserIdleService* aIdleService);
+
+  /**
+   * Initializes the daily idle observer.
+   * Keep this separated from the constructor, since it could cause pointer
+   * corruption due to AddRef/Release of "this".
+   */
+  void Init();
+
+ private:
+  virtual ~nsUserIdleServiceDaily();
+
+  /**
+   * StageIdleDaily is the interim call made when an idle-daily event is due.
+   * However we don't want to fire idle-daily until the user is idle for this
+   * session, so this sets up a short wait for an idle event which triggers
+   * the actual idle-daily event.
+   *
+   * @param aHasBeenLongWait Pass true indicating nsUserIdleServiceDaily is
+   * having trouble getting the idle-daily event fired. If true StageIdleDaily
+   * will use a shorter idle wait time before firing idle-daily.
+   */
+  void StageIdleDaily(bool aHasBeenLongWait);
+
+  /**
+   * @note This is a normal pointer, part to avoid creating a cycle with the
+   * idle service, part to avoid potential pointer corruption due to this class
+   * being instantiated in the constructor of the service itself.
+   */
+  nsIUserIdleService* mIdleService;
+
+  /**
+   * Place to hold the timer used by this class to determine when a day has
+   * passed, after that it will wait for idle time to be detected.
+   */
+  nsCOMPtr<nsITimer> mTimer;
+
+  /**
+   * Function that is called back once a day.
+   */
+  static void DailyCallback(nsITimer* aTimer, void* aClosure);
+
+  /**
+   * Cache of observers for the "idle-daily" category.
+   */
+  nsCategoryCache<nsIObserver> mCategoryObservers;
+
+  /**
+   * Next time we expect an idle-daily timer to fire, in case timers aren't
+   * very reliable on the platform. Value is in PR_Now microsecond units.
+   */
+  PRTime mExpectedTriggerTime;
+
+  /**
+   * Tracks which idle daily observer callback we ask for. There are two: a
+   * regular long idle wait and a shorter wait if we've been waiting to fire
+   * idle daily for an extended period. Set by StageIdleDaily.
+   */
+  int32_t mIdleDailyTriggerWait;
+};
+
+class nsUserIdleService : public nsIUserIdleServiceInternal {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIUSERIDLESERVICE NS_DECL_NSIUSERIDLESERVICEINTERNAL
+
+      protected : static already_AddRefed<nsUserIdleService>
+                  GetInstance();
+
+  nsUserIdleService();
+  virtual ~nsUserIdleService();
+
+  /**
+   * If there is a platform specific function to poll the system idel time
+   * then that must be returned in this function, and the function MUST return
+   * true, otherwise then the function should be left unimplemented or made
+   * to return false (this can also be used for systems where it depends on
+   * the configuration of the system if the idle time can be determined)
+   *
+   * @param aIdleTime
+   *        The idle time in ms.
+   *
+   * @return true if the idle time could be polled, false otherwise.
+   *
+   * @note The time returned by this function can be different than the one
+   *       returned by GetIdleTime, as that is corrected by any calls to
+   *       ResetIdleTimeOut(), unless you overwrite that function too...
+   */
+  virtual bool PollIdleTime(uint32_t* aIdleTime);
+
+ public:
+  void SetDisabledForShutdown();
+
+ private:
+  /**
+   * Ensure that the timer is expiring at least at the given time
+   *
+   * The function might not restart the timer if there is one running currently
+   *
+   * @param aNextTimeout
+   *        The last absolute time the timer should expire
+   */
+  void SetTimerExpiryIfBefore(mozilla::TimeStamp aNextTimeout);
+
+  /**
+   * Stores the next timeout time, 0 means timer not running
+   */
+  mozilla::TimeStamp mCurrentlySetToTimeoutAt;
+
+  /**
+   * mTimer holds the internal timer used by this class to detect when to poll
+   * for idle time, when to check if idle timers should expire etc.
+   */
+  nsCOMPtr<nsITimer> mTimer;
+
+  /**
+   * Array of listeners that wants to be notified about idle time.
+   */
+  nsTArray<IdleListener> mArrayListeners;
+
+  /**
+   * Object keeping track of the daily idle thingy.
+   */
+  RefPtr<nsUserIdleServiceDaily> mDailyIdle;
+
+  /**
+   * Number of observers currently in idle mode.
+   */
+  uint32_t mIdleObserverCount;
+
+  /**
+   * Delta time from last non idle time to when the next observer should switch
+   * to idle mode
+   *
+   * Time in seconds
+   *
+   * If this value is 0 it means there are no active observers
+   */
+  uint32_t mDeltaToNextIdleSwitchInS;
+
+  /**
+   * If true, the idle service is temporarily disabled, and all idle events
+   * will be ignored.
+   */
+  bool mDisabled = false;
+
+  /**
+   * Absolute value for when the last user interaction took place.
+   */
+  mozilla::TimeStamp mLastUserInteraction;
+
+  /**
+   * Function that ensures the timer is running with at least the minimum time
+   * needed.  It will kill the timer if there are no active observers.
+   */
+  void ReconfigureTimer(void);
+
+  /**
+   * Callback function that is called when the internal timer expires.
+   *
+   * This in turn calls the IdleTimerCallback that does the real processing
+   */
+  static void StaticIdleTimerCallback(nsITimer* aTimer, void* aClosure);
+
+  /**
+   * Function that handles when a timer has expired
+   */
+  void IdleTimerCallback(void);
+};
+
+#endif  // nsUserIdleService_h__
diff --git a/widget/nsWidgetsCID.h b/widget/nsWidgetsCID.h
new file mode 100644
index 0000000000..95c425f75e
--- /dev/null
+++ b/widget/nsWidgetsCID.h
@@ -0,0 +1,332 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* bd57cee8-1dd1-11b2-9fe7-95cf4709aea3 */
+#define NS_FILEPICKER_CID                            \
+  {                                                  \
+    0xbd57cee8, 0x1dd1, 0x11b2, {                    \
+      0x9f, 0xe7, 0x95, 0xcf, 0x47, 0x09, 0xae, 0xa3 \
+    }                                                \
+  }
+
+/* e221df9b-3d66-4045-9a66-5720949f8d10 */
+#define NS_APPLICATIONCHOOSER_CID                    \
+  {                                                  \
+    0xe221df9b, 0x3d66, 0x4045, {                    \
+      0x9a, 0x66, 0x57, 0x20, 0x94, 0x9f, 0x8d, 0x10 \
+    }                                                \
+  }
+
+/* 0f872c8c-3ee6-46bd-92a2-69652c6b474e */
+#define NS_COLORPICKER_CID                           \
+  {                                                  \
+    0x0f872c8c, 0x3ee6, 0x46bd, {                    \
+      0x92, 0xa2, 0x69, 0x65, 0x2c, 0x6b, 0x47, 0x4e \
+    }                                                \
+  }
+
+/* 2d96b3df-c051-11d1-a827-0040959a28c9 */
+#define NS_APPSHELL_CID                              \
+  {                                                  \
+    0x2d96b3df, 0xc051, 0x11d1, {                    \
+      0xa8, 0x27, 0x00, 0x40, 0x95, 0x9a, 0x28, 0xc9 \
+    }                                                \
+  }
+
+/* 2d96b3e0-c051-11d1-a827-0040959a28c9 */
+#define NS_TOOLKIT_CID                               \
+  {                                                  \
+    0x2d96b3e0, 0xc051, 0x11d1, {                    \
+      0xa8, 0x27, 0x00, 0x40, 0x95, 0x9a, 0x28, 0xc9 \
+    }                                                \
+  }
+
+/* 9A0CB62B-D638-4FAF-9588-AE96F5E29093 */
+#define NS_TASKBARPREVIEWCALLBACK_CID                \
+  {                                                  \
+    0x9a0cb62b, 0xd638, 0x4faf, {                    \
+      0x95, 0x88, 0xae, 0x96, 0xf5, 0xe2, 0x90, 0x93 \
+    }                                                \
+  }
+
+/*1201d357-8417-4926-a694-e6408fbedcf8*/
+#define NS_SHAREPICKER_CID                           \
+  {                                                  \
+    0x1201d357, 0x8417, 0x4926, {                    \
+      0xa6, 0x94, 0xe6, 0x40, 0x8f, 0xbe, 0xdc, 0xf8 \
+    }                                                \
+  }
+
+/* XXX the following CID's are not in order. This needs
+   to be fixed. */
+
+//-----------------------------------------------------------
+// Menus
+//-----------------------------------------------------------
+
+// {F6CD4F21-53AF-11d2-8DC4-00609703C14E}
+#define NS_POPUPMENU_CID                           \
+  {                                                \
+    0xf6cd4f21, 0x53af, 0x11d2, {                  \
+      0x8d, 0xc4, 0x0, 0x60, 0x97, 0x3, 0xc1, 0x4e \
+    }                                              \
+  }
+
+// {1F39AE50-B6A0-4B37-90F4-60AF614193D8}
+#define NS_STANDALONENATIVEMENU_CID                  \
+  {                                                  \
+    0x1F39AE50, 0xB6A0, 0x4B37, {                    \
+      0x90, 0xF4, 0x60, 0xAF, 0x61, 0x41, 0x93, 0xD8 \
+    }                                                \
+  }
+
+// {2451BAED-8DC3-46D9-9E30-96E1BAA03666}
+#define NS_MACDOCKSUPPORT_CID                        \
+  {                                                  \
+    0x2451BAED, 0x8DC3, 0x46D9, {                    \
+      0x9E, 0x30, 0x96, 0xE1, 0xBA, 0xA0, 0x36, 0x66 \
+    }                                                \
+  }
+
+// {74EA4101-A5BB-49BC-9984-66DA8B225A37}
+#define NS_MACFINDERPROGRESS_CID                     \
+  {                                                  \
+    0x74EA4101, 0xA5BB, 0x49BC, {                    \
+      0x99, 0x84, 0x66, 0xDA, 0x8B, 0x22, 0x5A, 0x37 \
+    }                                                \
+  }
+
+// {de59fe1a-46c8-490f-b04d-34545acb06c9}
+#define NS_MACSHARINGSERVICE_CID                     \
+  {                                                  \
+    0xde59fe1a, 0x46c8, 0x490f, {                    \
+      0xb0, 0x4d, 0x34, 0x54, 0x5a, 0xcb, 0x06, 0xc9 \
+    }                                                \
+  }
+
+// {29046c8f-cba6-4ffa-9141-1685e96c4ea0}
+#define NS_MACUSERACTIVITYUPDATER_CID                \
+  {                                                  \
+    0x29046c8f, 0xcba6, 0x4ffa, {                    \
+      0x91, 0x41, 0x16, 0x85, 0xe9, 0x6c, 0x4e, 0xa0 \
+    }                                                \
+  }
+
+// {b6e1a890-b2b8-4883-a65f-9476f6185313}
+#define NS_SYSTEMSTATUSBAR_CID                       \
+  {                                                  \
+    0xb6e1a890, 0xb2b8, 0x4883, {                    \
+      0xa6, 0x5f, 0x94, 0x76, 0xf6, 0x18, 0x53, 0x13 \
+    }                                                \
+  }
+
+// {ea109912-3acc-48de-b679-c23b6a122da5}
+#define NS_TOUCHBARHELPER_CID                        \
+  {                                                  \
+    0xea109912, 0x3acc, 0x48de, {                    \
+      0xb6, 0x79, 0xc2, 0x3b, 0x6a, 0x12, 0x2d, 0xa5 \
+    }                                                \
+  }
+
+// {38f396e2-93c9-4a77-aaf7-2d50b9962186}
+#define NS_TOUCHBARUPDATER_CID                       \
+  {                                                  \
+    0x38f396e2, 0x93c9, 0x4a77, {                    \
+      0xaa, 0xf7, 0x2d, 0x50, 0xb9, 0x96, 0x21, 0x86 \
+    }                                                \
+  }
+
+// {77441d17-f29c-49d7-982f-f20a5ab5a900}
+#define NS_TOUCHBARINPUT_CID                         \
+  {                                                  \
+    0x77441d17, 0xf29c, 0x49d7, {                    \
+      0x98, 0x2f, 0xf2, 0x0a, 0x5a, 0xb5, 0xa9, 0x00 \
+    }                                                \
+  }
+
+//-----------------------------------------------------------
+// Drag & Drop & Clipboard
+//-----------------------------------------------------------
+// {8B5314BB-DB01-11d2-96CE-0060B0FB9956}
+#define NS_DRAGSERVICE_CID                          \
+  {                                                 \
+    0x8b5314bb, 0xdb01, 0x11d2, {                   \
+      0x96, 0xce, 0x0, 0x60, 0xb0, 0xfb, 0x99, 0x56 \
+    }                                               \
+  }
+
+// {8B5314BC-DB01-11d2-96CE-0060B0FB9956}
+#define NS_TRANSFERABLE_CID                         \
+  {                                                 \
+    0x8b5314bc, 0xdb01, 0x11d2, {                   \
+      0x96, 0xce, 0x0, 0x60, 0xb0, 0xfb, 0x99, 0x56 \
+    }                                               \
+  }
+
+// {8B5314BA-DB01-11d2-96CE-0060B0FB9956}
+#define NS_CLIPBOARD_CID                            \
+  {                                                 \
+    0x8b5314ba, 0xdb01, 0x11d2, {                   \
+      0x96, 0xce, 0x0, 0x60, 0xb0, 0xfb, 0x99, 0x56 \
+    }                                               \
+  }
+
+// {77221D5A-1DD2-11B2-8C69-C710F15D2ED5}
+#define NS_CLIPBOARDHELPER_CID                       \
+  {                                                  \
+    0x77221d5a, 0x1dd2, 0x11b2, {                    \
+      0x8c, 0x69, 0xc7, 0x10, 0xf1, 0x5d, 0x2e, 0xd5 \
+    }                                                \
+  }
+
+// {8B5314BD-DB01-11d2-96CE-0060B0FB9956}
+#define NS_DATAFLAVOR_CID                           \
+  {                                                 \
+    0x8b5314bd, 0xdb01, 0x11d2, {                   \
+      0x96, 0xce, 0x0, 0x60, 0xb0, 0xfb, 0x99, 0x56 \
+    }                                               \
+  }
+
+// {948A0023-E3A7-11d2-96CF-0060B0FB9956}
+#define NS_HTMLFORMATCONVERTER_CID                  \
+  {                                                 \
+    0x948a0023, 0xe3a7, 0x11d2, {                   \
+      0x96, 0xcf, 0x0, 0x60, 0xb0, 0xfb, 0x99, 0x56 \
+    }                                               \
+  }
+
+//-----------------------------------------------------------
+// Other
+//-----------------------------------------------------------
+// {B148EED2-236D-11d3-B35C-00A0CC3C1CDE}
+#define NS_SOUND_CID                                \
+  {                                                 \
+    0xb148eed2, 0x236d, 0x11d3, {                   \
+      0xb3, 0x5c, 0x0, 0xa0, 0xcc, 0x3c, 0x1c, 0xde \
+    }                                               \
+  }
+
+#define NS_SCREENMANAGER_CID                         \
+  {                                                  \
+    0xc401eb80, 0xf9ea, 0x11d3, {                    \
+      0xbb, 0x6f, 0xe7, 0x32, 0xb7, 0x3e, 0xbe, 0x7c \
+    }                                                \
+  }
+
+// {6987230e-0089-4e78-bc5f-1493ee7519fa}
+#define NS_IDLE_SERVICE_CID                          \
+  {                                                  \
+    0x6987230e, 0x0098, 0x4e78, {                    \
+      0xbc, 0x5f, 0x14, 0x93, 0xee, 0x75, 0x19, 0xfa \
+    }                                                \
+  }
+
+#define NS_WIN_TASKBAR_CID                           \
+  {                                                  \
+    0xb8e5bc54, 0xa22f, 0x4eb2, {                    \
+      0xb0, 0x61, 0x24, 0xcb, 0x6d, 0x19, 0xc1, 0x5f \
+    }                                                \
+  }
+
+// {73A5946F-608D-454f-9D33-0B8F8C7294B6}
+#define NS_WIN_LEGACYJUMPLISTBUILDER_CID            \
+  {                                                 \
+    0x73a5946f, 0x608d, 0x454f, {                   \
+      0x9d, 0x33, 0xb, 0x8f, 0x8c, 0x72, 0x94, 0xb6 \
+    }                                               \
+  }
+
+// {2B9A1F2C-27CE-45b6-8D4E-755D0E34F8DB}
+#define NS_WIN_LEGACYJUMPLISTITEM_CID                \
+  {                                                  \
+    0x2b9a1f2c, 0x27ce, 0x45b6, {                    \
+      0x8d, 0x4e, 0x75, 0x5d, 0x0e, 0x34, 0xf8, 0xdb \
+    }                                                \
+  }
+
+// {21F1F13B-F75A-42ad-867A-D91AD694447E}
+#define NS_WIN_LEGACYJUMPLISTSEPARATOR_CID           \
+  {                                                  \
+    0x21f1f13b, 0xf75a, 0x42ad, {                    \
+      0x86, 0x7a, 0xd9, 0x1a, 0xd6, 0x94, 0x44, 0x7e \
+    }                                                \
+  }
+
+// {F72C5DC4-5A12-47be-BE28-AB105F33B08F}
+#define NS_WIN_LEGACYJUMPLISTLINK_CID                \
+  {                                                  \
+    0xf72c5dc4, 0x5a12, 0x47be, {                    \
+      0xbe, 0x28, 0xab, 0x10, 0x5f, 0x33, 0xb0, 0x8f \
+    }                                                \
+  }
+
+// {B16656B2-5187-498f-ABF4-56346126BFDB}
+#define NS_WIN_LEGACYJUMPLISTSHORTCUT_CID            \
+  {                                                  \
+    0xb16656b2, 0x5187, 0x498f, {                    \
+      0xab, 0xf4, 0x56, 0x34, 0x61, 0x26, 0xbf, 0xdb \
+    }                                                \
+  }
+
+// {e9096367-ddd9-45e4-b762-49c0c18b7119}
+#define NS_MACWEBAPPUTILS_CID                        \
+  {                                                  \
+    0xe9096367, 0xddd9, 0x45e4, {                    \
+      0xb7, 0x62, 0x49, 0xc0, 0xc1, 0x8b, 0x71, 0x19 \
+    }                                                \
+  }
+
+// {a9339876-0027-430f-b953-84c9c11c2da3}
+#define NS_GTK_TASKBARPROGRESS_CID                   \
+  {                                                  \
+    0xa9339876, 0x0027, 0x430f, {                    \
+      0xb9, 0x53, 0x84, 0xc9, 0xc1, 0x1c, 0x2d, 0xa3 \
+    }                                                \
+  }
+
+//-----------------------------------------------------------
+// Printing
+//-----------------------------------------------------------
+#define NS_DEVICE_CONTEXT_SPEC_CID                   \
+  {                                                  \
+    0xd3f69889, 0xe13a, 0x4321, {                    \
+      0x98, 0x0c, 0xa3, 0x93, 0x32, 0xe2, 0x1f, 0x34 \
+    }                                                \
+  }
+
+#define NS_PRINTSETTINGSSERVICE_CID                  \
+  {                                                  \
+    0x841387c8, 0x72e6, 0x484b, {                    \
+      0x92, 0x96, 0xbf, 0x6e, 0xea, 0x80, 0xd5, 0x8a \
+    }                                                \
+  }
+
+#define NS_PRINTER_LIST_CID                          \
+  {                                                  \
+    0xa6cf9129, 0x15b3, 0x11d2, {                    \
+      0x93, 0x2e, 0x00, 0x80, 0x5f, 0x8a, 0xdd, 0x32 \
+    }                                                \
+  }
+
+#define NS_PRINTDIALOGSERVICE_CID                    \
+  {                                                  \
+    0x06beec76, 0xa183, 0x4d9f, {                    \
+      0x85, 0xdd, 0x08, 0x5f, 0x26, 0xda, 0x56, 0x5a \
+    }                                                \
+  }
+
+#define NS_GFXINFO_CID                               \
+  {                                                  \
+    0xd755a760, 0x9f27, 0x11df, {                    \
+      0x08, 0x00, 0x20, 0x0c, 0x9a, 0x66, 0x42, 0x42 \
+    }                                                \
+  }
+
+#define NS_WINDOWS_UIUTILS_CID                       \
+  {                                                  \
+    0xe04a55e8, 0xfee3, 0x4ea2, {                    \
+      0xa9, 0x8b, 0x41, 0xd2, 0x62, 0x1a, 0xdc, 0x3c \
+    }                                                \
+  }
diff --git a/widget/nsXPLookAndFeel.cpp b/widget/nsXPLookAndFeel.cpp
new file mode 100644
index 0000000000..05b8952b04
--- /dev/null
+++ b/widget/nsXPLookAndFeel.cpp
@@ -0,0 +1,1547 @@
+/* -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+
+#include "mozilla/LookAndFeel.h"
+#include "nscore.h"
+
+#include "nsXPLookAndFeel.h"
+#include "nsLookAndFeel.h"
+#include "HeadlessLookAndFeel.h"
+#include "RemoteLookAndFeel.h"
+#include "nsContentUtils.h"
+#include "nsCRT.h"
+#include "nsFont.h"
+#include "nsIFrame.h"
+#include "nsIXULRuntime.h"
+#include "nsLayoutUtils.h"
+#include "Theme.h"
+#include "SurfaceCacheUtils.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/Services.h"
+#include "mozilla/ServoStyleSet.h"
+#include "mozilla/ServoCSSParser.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/StaticPrefs_editor.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/StaticPrefs_ui.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/PreferenceSheet.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/widget/WidgetMessageUtils.h"
+#include "mozilla/dom/KeyboardEventBinding.h"
+#include "mozilla/RelativeLuminanceUtils.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/TelemetryScalarEnums.h"
+#include "mozilla/Try.h"
+
+#include "gfxPlatform.h"
+#include "gfxFont.h"
+
+#include "qcms.h"
+
+#include <bitset>
+
+using namespace mozilla;
+
+using IntID = mozilla::LookAndFeel::IntID;
+using FloatID = mozilla::LookAndFeel::FloatID;
+using ColorID = mozilla::LookAndFeel::ColorID;
+using FontID = mozilla::LookAndFeel::FontID;
+
+template <typename Index, typename Value, Index kEnd>
+class EnumeratedCache {
+  mozilla::EnumeratedArray<Index, kEnd, Value> mEntries;
+  std::bitset<size_t(kEnd)> mValidity;
+
+ public:
+  constexpr EnumeratedCache() = default;
+
+  bool IsValid(Index aIndex) const { return mValidity[size_t(aIndex)]; }
+
+  const Value* Get(Index aIndex) const {
+    return IsValid(aIndex) ? &mEntries[aIndex] : nullptr;
+  }
+
+  void Insert(Index aIndex, Value aValue) {
+    mValidity[size_t(aIndex)] = true;
+    mEntries[aIndex] = aValue;
+  }
+
+  void Remove(Index aIndex) {
+    mValidity[size_t(aIndex)] = false;
+    mEntries[aIndex] = Value();
+  }
+
+  void Clear() {
+    mValidity.reset();
+    for (auto& entry : mEntries) {
+      entry = Value();
+    }
+  }
+};
+
+using ColorCache = EnumeratedCache<ColorID, Maybe<nscolor>, ColorID::End>;
+
+struct ColorCaches {
+  using UseStandins = LookAndFeel::UseStandins;
+
+  ColorCache mCaches[2][2];
+
+  constexpr ColorCaches() = default;
+
+  ColorCache& Get(ColorScheme aScheme, UseStandins aUseStandins) {
+    return mCaches[aScheme == ColorScheme::Dark]
+                  [aUseStandins == UseStandins::Yes];
+  }
+
+  void Clear() {
+    for (auto& c : mCaches) {
+      for (auto& cache : c) {
+        cache.Clear();
+      }
+    }
+  }
+};
+
+static ColorCaches sColorCaches;
+
+static EnumeratedCache<FloatID, Maybe<float>, FloatID::End> sFloatCache;
+static EnumeratedCache<IntID, Maybe<int32_t>, IntID::End> sIntCache;
+static EnumeratedCache<FontID, widget::LookAndFeelFont, FontID::End> sFontCache;
+
+// To make one of these prefs toggleable from a reftest add a user
+// pref in testing/profiles/reftest/user.js. For example, to make
+// ui.useAccessibilityTheme toggleable, add:
+//
+// user_pref("ui.useAccessibilityTheme", 0);
+//
+// This needs to be of the same length and in the same order as
+// LookAndFeel::IntID values.
+static const char sIntPrefs[][45] = {
+    "ui.caretBlinkTime",
+    "ui.caretBlinkCount",
+    "ui.caretWidth",
+    "ui.caretVisibleWithSelection",
+    "ui.selectTextfieldsOnKeyFocus",
+    "ui.submenuDelay",
+    "ui.menusCanOverlapOSBar",
+    "ui.useOverlayScrollbars",
+    "ui.allowOverlayScrollbarsOverlap",
+    "ui.skipNavigatingDisabledMenuItem",
+    "ui.dragThresholdX",
+    "ui.dragThresholdY",
+    "ui.useAccessibilityTheme",
+    "ui.scrollArrowStyle",
+    "ui.scrollButtonLeftMouseButtonAction",
+    "ui.scrollButtonMiddleMouseButtonAction",
+    "ui.scrollButtonRightMouseButtonAction",
+    "ui.treeOpenDelay",
+    "ui.treeCloseDelay",
+    "ui.treeLazyScrollDelay",
+    "ui.treeScrollDelay",
+    "ui.treeScrollLinesMax",
+    "accessibility.tabfocus",  // Weird one...
+    "ui.chosenMenuItemsShouldBlink",
+    "ui.windowsAccentColorInTitlebar",
+    "ui.macBigSurTheme",
+    "ui.macRTL",
+    "ui.alertNotificationOrigin",
+    "ui.scrollToClick",
+    "ui.IMERawInputUnderlineStyle",
+    "ui.IMESelectedRawTextUnderlineStyle",
+    "ui.IMEConvertedTextUnderlineStyle",
+    "ui.IMESelectedConvertedTextUnderlineStyle",
+    "ui.SpellCheckerUnderlineStyle",
+    "ui.menuBarDrag",
+    "ui.scrollbarButtonAutoRepeatBehavior",
+    "ui.tooltipDelay",
+    "ui.swipeAnimationEnabled",
+    "ui.scrollbarDisplayOnMouseMove",
+    "ui.scrollbarFadeBeginDelay",
+    "ui.scrollbarFadeDuration",
+    "ui.contextMenuOffsetVertical",
+    "ui.contextMenuOffsetHorizontal",
+    "ui.GtkCSDAvailable",
+    "ui.GtkCSDMinimizeButton",
+    "ui.GtkCSDMaximizeButton",
+    "ui.GtkCSDCloseButton",
+    "ui.GtkCSDMinimizeButtonPosition",
+    "ui.GtkCSDMaximizeButtonPosition",
+    "ui.GtkCSDCloseButtonPosition",
+    "ui.GtkCSDReversedPlacement",
+    "ui.systemUsesDarkTheme",
+    "ui.prefersReducedMotion",
+    "ui.prefersReducedTransparency",
+    "ui.invertedColors",
+    "ui.primaryPointerCapabilities",
+    "ui.allPointerCapabilities",
+    "ui.systemScrollbarSize",
+    "ui.touchDeviceSupportPresent",
+    "ui.titlebarRadius",
+    "ui.dynamicRange",
+    "ui.videoDynamicRange",
+    "ui.panelAnimations",
+    "ui.hideCursorWhileTyping",
+    "ui.gtkThemeFamily",
+};
+
+static_assert(ArrayLength(sIntPrefs) == size_t(LookAndFeel::IntID::End),
+              "Should have a pref for each int value");
+
+// This array MUST be kept in the same order as the float id list in
+// LookAndFeel.h
+// clang-format off
+static const char sFloatPrefs[][37] = {
+    "ui.IMEUnderlineRelativeSize",
+    "ui.SpellCheckerUnderlineRelativeSize",
+    "ui.caretAspectRatio",
+    "ui.textScaleFactor",
+    "ui.cursorScale",
+};
+// clang-format on
+
+static_assert(ArrayLength(sFloatPrefs) == size_t(LookAndFeel::FloatID::End),
+              "Should have a pref for each float value");
+
+// This array MUST be kept in the same order as the color list in
+// specified/color.rs
+static const char sColorPrefs[][41] = {
+    "ui.activeborder",
+    "ui.activecaption",
+    "ui.appworkspace",
+    "ui.background",
+    "ui.buttonface",
+    "ui.buttonhighlight",
+    "ui.buttonshadow",
+    "ui.buttontext",
+    "ui.buttonborder",
+    "ui.captiontext",
+    "ui.-moz-field",
+    "ui.-moz-disabledfield",
+    "ui.-moz-fieldtext",
+    "ui.mark",
+    "ui.marktext",
+    "ui.-moz-comboboxtext",
+    "ui.-moz-combobox",
+    "ui.graytext",
+    "ui.highlight",
+    "ui.highlighttext",
+    "ui.inactiveborder",
+    "ui.inactivecaption",
+    "ui.inactivecaptiontext",
+    "ui.infobackground",
+    "ui.infotext",
+    "ui.menu",
+    "ui.menutext",
+    "ui.scrollbar",
+    "ui.threeddarkshadow",
+    "ui.threedface",
+    "ui.threedhighlight",
+    "ui.threedlightshadow",
+    "ui.threedshadow",
+    "ui.window",
+    "ui.windowframe",
+    "ui.windowtext",
+    "ui.-moz-default-color",
+    "ui.-moz-default-background-color",
+    "ui.-moz-dialog",
+    "ui.-moz-dialogtext",
+    "ui.-moz-cellhighlight",
+    "ui.-moz_cellhighlighttext",
+    "ui.selecteditem",
+    "ui.selecteditemtext",
+    "ui.-moz-buttonhoverface",
+    "ui.-moz_buttonhovertext",
+    "ui.-moz_menuhover",
+    "ui.-moz_menuhoverdisabled",
+    "ui.-moz_menuhovertext",
+    "ui.-moz_menubarhovertext",
+    "ui.-moz_eventreerow",
+    "ui.-moz_oddtreerow",
+    "ui.-moz-buttonactivetext",
+    "ui.-moz-buttonactiveface",
+    "ui.-moz-buttondisabledface",
+    "ui.-moz-headerbar",
+    "ui.-moz-headerbartext",
+    "ui.-moz-headerbarinactive",
+    "ui.-moz-headerbarinactivetext",
+    "ui.-moz-mac-defaultbuttontext",
+    "ui.-moz-mac-focusring",
+    "ui.-moz_mac_disabledtoolbartext",
+    "ui.-moz-sidebar",
+    "ui.-moz-sidebartext",
+    "ui.-moz-sidebarborder",
+    "ui.accentcolor",
+    "ui.accentcolortext",
+    "ui.-moz-autofill-background",
+    "ui.-moz-nativehyperlinktext",
+    "ui.-moz-nativevisitedhyperlinktext",
+    "ui.-moz-hyperlinktext",
+    "ui.-moz-activehyperlinktext",
+    "ui.-moz-visitedhyperlinktext",
+    "ui.-moz-colheader",
+    "ui.-moz-colheadertext",
+    "ui.-moz-colheaderhover",
+    "ui.-moz-colheaderhovertext",
+    "ui.-moz-colheaderactive",
+    "ui.-moz-colheaderactivetext",
+    "ui.textSelectDisabledBackground",
+    "ui.textSelectAttentionBackground",
+    "ui.textSelectAttentionForeground",
+    "ui.textHighlightBackground",
+    "ui.textHighlightForeground",
+    "ui.IMERawInputBackground",
+    "ui.IMERawInputForeground",
+    "ui.IMERawInputUnderline",
+    "ui.IMESelectedRawTextBackground",
+    "ui.IMESelectedRawTextForeground",
+    "ui.IMESelectedRawTextUnderline",
+    "ui.IMEConvertedTextBackground",
+    "ui.IMEConvertedTextForeground",
+    "ui.IMEConvertedTextUnderline",
+    "ui.IMESelectedConvertedTextBackground",
+    "ui.IMESelectedConvertedTextForeground",
+    "ui.IMESelectedConvertedTextUnderline",
+    "ui.SpellCheckerUnderline",
+    "ui.themedScrollbar",
+    "ui.themedScrollbarInactive",
+    "ui.themedScrollbarThumb",
+    "ui.themedScrollbarThumbHover",
+    "ui.themedScrollbarThumbActive",
+    "ui.themedScrollbarThumbInactive",
+};
+
+static_assert(ArrayLength(sColorPrefs) == size_t(LookAndFeel::ColorID::End),
+              "Should have a pref for each color value");
+
+// This array MUST be kept in the same order as the SystemFont enum.
+static const char sFontPrefs[][41] = {
+    "ui.font.caption",
+    "ui.font.icon",
+    "ui.font.menu",
+    "ui.font.message-box",
+    "ui.font.small-caption",
+    "ui.font.status-bar",
+    "ui.font.-moz-pull-down-menu",
+    "ui.font.-moz-button",
+    "ui.font.-moz-list",
+    "ui.font.-moz-field",
+};
+
+static_assert(ArrayLength(sFontPrefs) == size_t(LookAndFeel::FontID::End),
+              "Should have a pref for each font value");
+
+const char* nsXPLookAndFeel::GetColorPrefName(ColorID aId) {
+  return sColorPrefs[size_t(aId)];
+}
+
+bool nsXPLookAndFeel::sInitialized = false;
+
+nsXPLookAndFeel* nsXPLookAndFeel::sInstance = nullptr;
+bool nsXPLookAndFeel::sShutdown = false;
+
+auto LookAndFeel::SystemZoomSettings() -> ZoomSettings {
+  ZoomSettings settings;
+  switch (StaticPrefs::browser_display_os_zoom_behavior()) {
+    case 0:
+    default:
+      break;
+    case 1:
+      settings.mFullZoom = GetTextScaleFactor();
+      break;
+    case 2:
+      settings.mTextZoom = GetTextScaleFactor();
+      break;
+  }
+  return settings;
+}
+
+// static
+nsXPLookAndFeel* nsXPLookAndFeel::GetInstance() {
+  if (sInstance) {
+    return sInstance;
+  }
+
+  NS_ENSURE_TRUE(!sShutdown, nullptr);
+
+  // If we're in a content process, then the parent process will have supplied
+  // us with an initial FullLookAndFeel object.
+  // We grab this data from the ContentChild,
+  // where it's been temporarily stashed, and initialize our new LookAndFeel
+  // object with it.
+
+  FullLookAndFeel* lnf = nullptr;
+
+  if (auto* cc = mozilla::dom::ContentChild::GetSingleton()) {
+    lnf = &cc->BorrowLookAndFeelData();
+  }
+
+  if (lnf) {
+    sInstance = new widget::RemoteLookAndFeel(std::move(*lnf));
+  } else if (gfxPlatform::IsHeadless()) {
+    sInstance = new widget::HeadlessLookAndFeel();
+  } else {
+    sInstance = new nsLookAndFeel();
+  }
+
+  // This is only ever used once during initialization, and can be cleared now.
+  if (lnf) {
+    *lnf = {};
+  }
+
+  widget::Theme::Init();
+  return sInstance;
+}
+
+// static
+void nsXPLookAndFeel::Shutdown() {
+  if (sShutdown) {
+    return;
+  }
+
+  sShutdown = true;
+  delete sInstance;
+  sInstance = nullptr;
+
+  // This keeps strings alive, so need to clear to make leak checking happy.
+  sFontCache.Clear();
+
+  widget::Theme::Shutdown();
+}
+
+static void IntPrefChanged(const nsACString& aPref) {
+  // Most Int prefs can't change our system colors or fonts, but
+  // ui.systemUsesDarkTheme can, since it affects the effective color-scheme
+  // (affecting system colors).
+  auto changeKind = aPref.EqualsLiteral("ui.systemUsesDarkTheme")
+                        ? widget::ThemeChangeKind::Style
+                        : widget::ThemeChangeKind::MediaQueriesOnly;
+  LookAndFeel::NotifyChangedAllWindows(changeKind);
+}
+
+static void FloatPrefChanged(const nsACString& aPref) {
+  // Most float prefs can't change our system colors or fonts, but
+  // textScaleFactor affects layout.
+  auto changeKind = aPref.EqualsLiteral("ui.textScaleFactor")
+                        ? widget::ThemeChangeKind::StyleAndLayout
+                        : widget::ThemeChangeKind::MediaQueriesOnly;
+  LookAndFeel::NotifyChangedAllWindows(changeKind);
+}
+
+static void ColorPrefChanged() {
+  // Color prefs affect style, because they by definition change system colors.
+  LookAndFeel::NotifyChangedAllWindows(widget::ThemeChangeKind::Style);
+}
+
+static void FontPrefChanged() {
+  // Color prefs affect style, because they by definition change system fonts.
+  LookAndFeel::NotifyChangedAllWindows(widget::ThemeChangeKind::Style);
+}
+
+// static
+void nsXPLookAndFeel::OnPrefChanged(const char* aPref, void* aClosure) {
+  nsDependentCString prefName(aPref);
+  for (const char* pref : sIntPrefs) {
+    if (prefName.Equals(pref)) {
+      IntPrefChanged(prefName);
+      return;
+    }
+  }
+
+  for (const char* pref : sFloatPrefs) {
+    if (prefName.Equals(pref)) {
+      FloatPrefChanged(prefName);
+      return;
+    }
+  }
+
+  for (const char* pref : sColorPrefs) {
+    // We use StringBeginsWith to handle .dark prefs too.
+    if (StringBeginsWith(prefName, nsDependentCString(pref))) {
+      ColorPrefChanged();
+      return;
+    }
+  }
+
+  for (const char* pref : sFontPrefs) {
+    if (StringBeginsWith(prefName, nsDependentCString(pref))) {
+      FontPrefChanged();
+      return;
+    }
+  }
+}
+
+static constexpr struct {
+  nsLiteralCString mName;
+  widget::ThemeChangeKind mChangeKind =
+      widget::ThemeChangeKind::MediaQueriesOnly;
+} kMediaQueryPrefs[] = {
+    // Affects whether standins are used for the accent color.
+    {"widget.non-native-theme.use-theme-accent"_ns,
+     widget::ThemeChangeKind::Style},
+    // These three affect system colors on Windows.
+    {"widget.windows.uwp-system-colors.enabled"_ns,
+     widget::ThemeChangeKind::Style},
+    {"widget.windows.uwp-system-colors.highlight-accent"_ns,
+     widget::ThemeChangeKind::Style},
+    // Affects env().
+    {"layout.css.prefers-color-scheme.content-override"_ns,
+     widget::ThemeChangeKind::Style},
+    // Affects media queries and scrollbar sizes, so gotta relayout.
+    {"widget.gtk.overlay-scrollbars.enabled"_ns,
+     widget::ThemeChangeKind::StyleAndLayout},
+    // Affects zoom settings which includes text and full zoom.
+    {"browser.display.os-zoom-behavior"_ns,
+     widget::ThemeChangeKind::StyleAndLayout},
+    // This affects system colors on Linux.
+    {"widget.gtk.libadwaita-colors.enabled"_ns, widget::ThemeChangeKind::Style},
+    // This affects not only the media query, but also the native theme, so we
+    // need to re-layout.
+    {"browser.theme.toolbar-theme"_ns, widget::ThemeChangeKind::AllBits},
+    {"browser.theme.content-theme"_ns},
+};
+
+// Read values from the user's preferences.
+// This is done once at startup, but since the user's preferences
+// haven't actually been read yet at that time, we also have to
+// set a callback to inform us of changes to each pref.
+void nsXPLookAndFeel::Init() {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+
+  // Say we're already initialized, and take the chance that it might fail;
+  // protects against some other process writing to our static variables.
+  sInitialized = true;
+
+  if (XRE_IsParentProcess()) {
+    nsLayoutUtils::RecomputeSmoothScrollDefault();
+  }
+
+  // XXX If we could reorganize the pref names, we should separate the branch
+  //     for each types.  Then, we could reduce the unnecessary loop from
+  //     nsXPLookAndFeel::OnPrefChanged().
+  Preferences::RegisterPrefixCallback(OnPrefChanged, "ui.");
+  // We really do just want the accessibility.tabfocus pref, not other prefs
+  // that start with that string.
+  Preferences::RegisterCallback(OnPrefChanged, "accessibility.tabfocus");
+
+  for (const auto& pref : kMediaQueryPrefs) {
+    Preferences::RegisterCallback(
+        [](const char*, void* aChangeKind) {
+          auto changeKind =
+              widget::ThemeChangeKind(reinterpret_cast<uintptr_t>(aChangeKind));
+          LookAndFeel::NotifyChangedAllWindows(changeKind);
+        },
+        pref.mName, reinterpret_cast<void*>(uintptr_t(pref.mChangeKind)));
+  }
+}
+
+nsXPLookAndFeel::~nsXPLookAndFeel() {
+  NS_ASSERTION(sInstance == this,
+               "This destroying instance isn't the singleton instance");
+  sInstance = nullptr;
+}
+
+static bool IsSpecialColor(LookAndFeel::ColorID aID, nscolor aColor) {
+  using ColorID = LookAndFeel::ColorID;
+
+  if (aColor == NS_SAME_AS_FOREGROUND_COLOR) {
+    return true;
+  }
+
+  switch (aID) {
+    case ColorID::IMESelectedRawTextBackground:
+    case ColorID::IMESelectedConvertedTextBackground:
+    case ColorID::IMERawInputBackground:
+    case ColorID::IMEConvertedTextBackground:
+    case ColorID::IMESelectedRawTextForeground:
+    case ColorID::IMESelectedConvertedTextForeground:
+    case ColorID::IMERawInputForeground:
+    case ColorID::IMEConvertedTextForeground:
+    case ColorID::IMERawInputUnderline:
+    case ColorID::IMEConvertedTextUnderline:
+    case ColorID::IMESelectedRawTextUnderline:
+    case ColorID::IMESelectedConvertedTextUnderline:
+    case ColorID::SpellCheckerUnderline:
+      return NS_IS_SELECTION_SPECIAL_COLOR(aColor);
+    default:
+      break;
+  }
+  /*
+   * In GetColor(), every color that is not a special color is color
+   * corrected. Use false to make other colors color corrected.
+   */
+  return false;
+}
+
+nscolor nsXPLookAndFeel::GetStandinForNativeColor(ColorID aID,
+                                                  ColorScheme aScheme) {
+  if (aScheme == ColorScheme::Dark) {
+    if (auto color = GenericDarkColor(aID)) {
+      return *color;
+    }
+  }
+
+  // The stand-in colors are taken from what the non-native theme needs (for
+  // field/button colors), the Windows 7 Aero theme except Mac-specific colors
+  // which are taken from Mac OS 10.7.
+
+#define COLOR(name_, r, g, b) \
+  case ColorID::name_:        \
+    return NS_RGB(r, g, b);
+
+#define COLORA(name_, r, g, b, a) \
+  case ColorID::name_:            \
+    return NS_RGBA(r, g, b, a);
+
+  switch (aID) {
+    // These are here for the purposes of headless mode.
+    case ColorID::IMESelectedRawTextBackground:
+    case ColorID::IMESelectedConvertedTextBackground:
+    case ColorID::IMERawInputBackground:
+    case ColorID::IMEConvertedTextBackground:
+      return NS_TRANSPARENT;
+    case ColorID::IMESelectedRawTextForeground:
+    case ColorID::IMESelectedConvertedTextForeground:
+    case ColorID::IMERawInputForeground:
+    case ColorID::IMEConvertedTextForeground:
+      return NS_SAME_AS_FOREGROUND_COLOR;
+    case ColorID::IMERawInputUnderline:
+    case ColorID::IMEConvertedTextUnderline:
+      return NS_40PERCENT_FOREGROUND_COLOR;
+    case ColorID::Accentcolor:
+      return widget::sDefaultAccent.ToABGR();
+    case ColorID::Accentcolortext:
+      return widget::sDefaultAccentText.ToABGR();
+      COLOR(SpellCheckerUnderline, 0xff, 0x00, 0x00)
+      COLOR(TextSelectDisabledBackground, 0xAA, 0xAA, 0xAA)
+
+      // Titlebar colors
+      // deprecated in CSS Color Level 4, same as Buttonborder:
+      COLOR(Activeborder, 0xE3, 0xE3, 0xE3)
+      // deprecated in CSS Color Level 4, same as Buttonborder:
+      COLOR(Inactiveborder, 0xE3, 0xE3, 0xE3)
+      // deprecated in CSS Color Level 4, same as Canvas/Window:
+      COLOR(Activecaption, 0xFF, 0xFF, 0xFF)
+      // deprecated in CSS Color Level 4, same as Canvas/Window:
+      COLOR(Inactivecaption, 0xFF, 0xFF, 0xFF)
+      // deprecated in CSS Color Level 4, same as Canvastext/Windowtext:
+      COLOR(Captiontext, 0x00, 0x00, 0x00)
+      // deprecated in CSS Color Level 4, same as Graytext:
+      COLOR(Inactivecaptiontext, 0x6D, 0x6D, 0x6D)
+
+      // CSS 2 colors:
+      // deprecated in CSS Color Level 4, same as Canvas/Window:
+      COLOR(Appworkspace, 0xFF, 0xFF, 0xFF)
+      // deprecated in CSS Color Level 4, same as Canvas/Window:
+      COLOR(Background, 0xFF, 0xFF, 0xFF)
+      // deprecated in CSS Color Level 4, same as Buttonface:
+      COLOR(Buttonhighlight, 0xE9, 0xE9, 0xED)
+      // deprecated in CSS Color Level 4, same as Buttonface:
+      COLOR(Buttonshadow, 0xE9, 0xE9, 0xED)
+
+      // Buttons and comboboxes should be kept in sync since they are drawn with
+      // the same colors by the non-native theme.
+      COLOR(Buttonface, 0xE9, 0xE9, 0xED)
+      COLORA(MozButtondisabledface, 0xE9, 0xE9, 0xED, 128)
+
+      COLOR(MozCombobox, 0xE9, 0xE9, 0xED)
+
+      COLOR(Buttontext, 0x00, 0x00, 0x00)
+      COLOR(MozComboboxtext, 0x00, 0x00, 0x00)
+
+      COLOR(Graytext, 0x6D, 0x6D, 0x6D)
+      COLOR(Highlight, 0x33, 0x99, 0xFF)
+      COLOR(Highlighttext, 0xFF, 0xFF, 0xFF)
+      // deprecated in CSS Color Level 4, same as Canvas/Window:
+      COLOR(Infobackground, 0xFF, 0xFF, 0xFF)
+      // deprecated in CSS Color Level 4, same as Canvastext/Windowtext:
+      COLOR(Infotext, 0x00, 0x00, 0x00)
+      // deprecated in CSS Color Level 4, same as Canvas/Window:
+      COLOR(Menu, 0xFF, 0xFF, 0xFF)
+      // deprecated in CSS Color Level 4, same as Canvastext/Windowtext:
+      COLOR(Menutext, 0x00, 0x00, 0x00)
+      // deprecated in CSS Color Level 4, same as Canvas/Window:
+      COLOR(Scrollbar, 0xFF, 0xFF, 0xFF)
+      // deprecated in CSS Color Level 4, same as Buttonborder:
+      COLOR(Threeddarkshadow, 0xE3, 0xE3, 0xE3)
+      // deprecated in CSS Color Level 4, same as Buttonface:
+      COLOR(Threedface, 0xE9, 0xE9, 0xED)
+      // deprecated in CSS Color Level 4, same as Buttonborder:
+      COLOR(Threedhighlight, 0xE3, 0xE3, 0xE3)
+      COLOR(Threedlightshadow, 0xE3, 0xE3, 0xE3)
+      // deprecated in CSS Color Level 4, same as Buttonborder:
+      COLOR(Threedshadow, 0xE3, 0xE3, 0xE3)
+      COLOR(Buttonborder, 0xE3, 0xE3, 0xE3)
+      COLOR(Mark, 0xFF, 0xFF, 0x00)
+      COLOR(Marktext, 0x00, 0x00, 0x00)
+      COLOR(Window, 0xFF, 0xFF, 0xFF)
+      // deprecated in CSS Color Level 4, same as Buttonborder:
+      COLOR(Windowframe, 0xE3, 0xE3, 0xE3)
+      COLOR(Windowtext, 0x00, 0x00, 0x00)
+      COLOR(Field, 0xFF, 0xFF, 0xFF)
+      COLORA(MozDisabledfield, 0xFF, 0xFF, 0xFF, 128)
+      COLOR(Fieldtext, 0x00, 0x00, 0x00)
+      COLOR(MozDialog, 0xF0, 0xF0, 0xF0)
+      COLOR(MozDialogtext, 0x00, 0x00, 0x00)
+      COLOR(MozColheadertext, 0x00, 0x00, 0x00)
+      COLOR(MozColheaderhovertext, 0x00, 0x00, 0x00)
+      COLOR(MozCellhighlight, 0xF0, 0xF0, 0xF0)
+      COLOR(MozCellhighlighttext, 0x00, 0x00, 0x00)
+      COLOR(Selecteditem, 0x33, 0x99, 0xFF)
+      COLOR(Selecteditemtext, 0xFF, 0xFF, 0xFF)
+      COLOR(MozButtonhoverface, 0xd0, 0xd0, 0xd7)
+      COLOR(MozButtonhovertext, 0x00, 0x00, 0x00)
+      COLOR(MozButtonactiveface, 0xb1, 0xb1, 0xb9)
+      COLOR(MozButtonactivetext, 0x00, 0x00, 0x00)
+      COLOR(MozMenuhover, 0x33, 0x99, 0xFF)
+      COLOR(MozMenuhovertext, 0x00, 0x00, 0x00)
+      COLOR(MozMenubarhovertext, 0x00, 0x00, 0x00)
+      COLOR(MozMenuhoverdisabled, 0xF0, 0xF0, 0xF0)
+      COLOR(MozEventreerow, 0xFF, 0xFF, 0xFF)
+      COLOR(MozOddtreerow, 0xFF, 0xFF, 0xFF)
+      COLOR(MozMacFocusring, 0x60, 0x9D, 0xD7)
+      COLOR(MozMacDisabledtoolbartext, 0x3F, 0x3F, 0x3F)
+      // Seems to be the default color (hardcoded because of bug 1065998)
+      COLOR(MozNativehyperlinktext, 0x00, 0x66, 0xCC)
+      COLOR(MozNativevisitedhyperlinktext, 0x55, 0x1A, 0x8B)
+    default:
+      break;
+  }
+  return NS_RGB(0xFF, 0xFF, 0xFF);
+}
+
+#undef COLOR
+#undef COLORA
+
+// Taken from in-content/common.inc.css's dark theme.
+Maybe<nscolor> nsXPLookAndFeel::GenericDarkColor(ColorID aID) {
+  nscolor color = NS_RGB(0, 0, 0);
+  static constexpr nscolor kWindowBackground = NS_RGB(28, 27, 34);
+  static constexpr nscolor kWindowText = NS_RGB(251, 251, 254);
+  switch (aID) {
+    case ColorID::Window:  // --in-content-page-background
+    case ColorID::Background:
+    case ColorID::Appworkspace:
+    case ColorID::Scrollbar:
+    case ColorID::Infobackground:
+      color = kWindowBackground;
+      break;
+
+    case ColorID::Menu:
+      color = NS_RGB(0x2b, 0x2a, 0x33);
+      break;
+
+    case ColorID::MozMenuhovertext:
+    case ColorID::MozMenubarhovertext:
+    case ColorID::Menutext:
+      color = NS_RGB(0xfb, 0xfb, 0xfe);
+      break;
+
+    case ColorID::MozMenuhover:
+      color = NS_RGB(0x52, 0x52, 0x5e);
+      break;
+
+    case ColorID::MozMenuhoverdisabled:
+      color = NS_RGB(0x3a, 0x39, 0x44);
+      break;
+
+    case ColorID::MozEventreerow:
+    case ColorID::MozOddtreerow:
+    case ColorID::MozDialog:  // --in-content-box-background
+      color = NS_RGB(35, 34, 43);
+      break;
+    case ColorID::Windowtext:  // --in-content-page-color
+    case ColorID::MozDialogtext:
+    case ColorID::MozSidebartext:
+    case ColorID::Fieldtext:
+    case ColorID::Infotext:
+    case ColorID::Buttontext:  // --in-content-button-text-color (via
+                               // --in-content-page-color)
+    case ColorID::MozComboboxtext:
+    case ColorID::MozButtonhovertext:
+    case ColorID::MozButtonactivetext:
+    case ColorID::MozHeaderbartext:
+    case ColorID::MozHeaderbarinactivetext:
+    case ColorID::Captiontext:
+    case ColorID::Inactivecaptiontext:  // TODO(emilio): Maybe make
+                                        // Inactivecaptiontext Graytext?
+    case ColorID::MozColheadertext:
+    case ColorID::MozColheaderhovertext:
+    case ColorID::MozColheaderactivetext:
+      color = kWindowText;
+      break;
+    case ColorID::Buttonshadow:
+    case ColorID::Threedshadow:
+    case ColorID::MozSidebarborder:
+    case ColorID::Threedlightshadow:
+    case ColorID::Threedhighlight:
+    case ColorID::Windowframe:
+    case ColorID::Buttonborder:  // --in-content-box-border-color computed
+                                 // with kWindowText above
+                                 // kWindowBackground.
+    case ColorID::Graytext:      // opacity: 0.4 of kWindowText blended over the
+                             // "Window" background color, which happens to be
+                             // the same :-)
+      color = NS_ComposeColors(kWindowBackground, NS_RGBA(251, 251, 254, 102));
+      break;
+    case ColorID::MozCellhighlight:
+    case ColorID::Selecteditem:  // --in-content-primary-button-background /
+                                 // --in-content-item-selected
+      color = NS_RGB(0, 221, 255);
+      break;
+    case ColorID::MozSidebar:
+    case ColorID::Field:
+    case ColorID::Buttonface:  // --in-content-button-background
+    case ColorID::Buttonhighlight:
+    case ColorID::MozColheader:
+    case ColorID::Threedface:
+    case ColorID::MozCombobox:
+    case ColorID::MozCellhighlighttext:
+    case ColorID::Selecteditemtext:  // --in-content-primary-button-text-color /
+                                     // --in-content-item-selected-text
+      color = NS_RGB(43, 42, 51);
+      break;
+    case ColorID::Threeddarkshadow:  // Same as Threedlightshadow but with the
+                                     // background.
+    case ColorID::MozDisabledfield:  // opacity: 0.4 of the face above blended
+                                     // over the "Window" background color.
+    case ColorID::MozButtondisabledface:
+      color = NS_ComposeColors(kWindowBackground, NS_RGBA(43, 42, 51, 102));
+      break;
+    case ColorID::MozButtonhoverface:  // --in-content-button-background-hover
+    case ColorID::MozColheaderhover:
+      color = NS_RGB(82, 82, 94);
+      break;
+    case ColorID::MozButtonactiveface:  // --in-content-button-background-active
+    case ColorID::MozColheaderactive:
+      color = NS_RGB(91, 91, 102);
+      break;
+    case ColorID::Highlight:
+      color = NS_RGBA(0, 221, 255, 78);
+      break;
+    case ColorID::Highlighttext:
+      color = NS_SAME_AS_FOREGROUND_COLOR;
+      break;
+    case ColorID::MozNativehyperlinktext:
+      // If you change this color, you probably also want to change the default
+      // value of browser.anchor_color.dark.
+      color = NS_RGB(0x8c, 0x8c, 0xff);
+      break;
+    case ColorID::MozNativevisitedhyperlinktext:
+      // If you change this color, you probably also want to change the default
+      // value of browser.visited_color.dark.
+      color = NS_RGB(0xff, 0xad, 0xff);
+      break;
+    case ColorID::SpellCheckerUnderline:
+      // This is the default for active links in dark mode as well
+      // (browser.active_color.dark). See bug 1755564 for some analysis and
+      // other options too.
+      color = NS_RGB(0xff, 0x66, 0x66);
+      break;
+    case ColorID::Activeborder:
+    case ColorID::Inactiveborder:
+      color = NS_RGB(57, 57, 57);
+      break;
+    case ColorID::MozHeaderbar:
+    case ColorID::MozHeaderbarinactive:
+    case ColorID::Activecaption:
+    case ColorID::Inactivecaption:
+      color = NS_RGB(28, 27, 34);
+      break;
+    default:
+      return Nothing();
+  }
+  return Some(color);
+}
+
+// Uncomment the #define below if you want to debug system color use in a skin
+// that uses them.  When set, it will make all system color pairs that are
+// appropriate for foreground/background pairing the same.  This means if the
+// skin is using system colors correctly you will not be able to see *any* text.
+//
+// #define DEBUG_SYSTEM_COLOR_USE
+
+#ifdef DEBUG_SYSTEM_COLOR_USE
+static nsresult SystemColorUseDebuggingColor(LookAndFeel::ColorID aID,
+                                             nscolor& aResult) {
+  using ColorID = LookAndFeel::ColorID;
+
+  switch (aID) {
+      // css2  http://www.w3.org/TR/REC-CSS2/ui.html#system-colors
+    case ColorID::Activecaption:
+      // active window caption background
+    case ColorID::Captiontext:
+      // text in active window caption
+      aResult = NS_RGB(0xff, 0x00, 0x00);
+      break;
+
+    case ColorID::Highlight:
+      // background of selected item
+    case ColorID::Highlighttext:
+      // text of selected item
+      aResult = NS_RGB(0xff, 0xff, 0x00);
+      break;
+
+    case ColorID::Inactivecaption:
+      // inactive window caption
+    case ColorID::Inactivecaptiontext:
+      // text in inactive window caption
+      aResult = NS_RGB(0x66, 0x66, 0x00);
+      break;
+
+    case ColorID::Infobackground:
+      // tooltip background color
+    case ColorID::Infotext:
+      // tooltip text color
+      aResult = NS_RGB(0x00, 0xff, 0x00);
+      break;
+
+    case ColorID::Menu:
+      // menu background
+    case ColorID::Menutext:
+      // menu text
+      aResult = NS_RGB(0x00, 0xff, 0xff);
+      break;
+
+    case ColorID::Threedface:
+    case ColorID::Buttonface:
+      // 3-D face color
+    case ColorID::Buttontext:
+      // text on push buttons
+      aResult = NS_RGB(0x00, 0x66, 0x66);
+      break;
+
+    case ColorID::Window:
+    case ColorID::Windowtext:
+      aResult = NS_RGB(0x00, 0x00, 0xff);
+      break;
+
+      // from the CSS3 working draft (not yet finalized)
+      // http://www.w3.org/tr/2000/wd-css3-userint-20000216.html#color
+
+    case ColorID::Field:
+    case ColorID::Fieldtext:
+      aResult = NS_RGB(0xff, 0x00, 0xff);
+      break;
+
+    case ColorID::MozDialog:
+    case ColorID::MozDialogtext:
+      aResult = NS_RGB(0x66, 0x00, 0x66);
+      break;
+
+    default:
+      return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  return NS_OK;
+}
+#endif
+
+static nsresult GetPrefColor(const char* aPref, nscolor& aResult) {
+  nsAutoCString colorStr;
+  MOZ_TRY(Preferences::GetCString(aPref, colorStr));
+  if (!ServoCSSParser::ComputeColor(nullptr, NS_RGB(0, 0, 0), colorStr,
+                                    &aResult)) {
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+static nsresult GetColorFromPref(LookAndFeel::ColorID aID, ColorScheme aScheme,
+                                 nscolor& aResult) {
+  const char* prefName = sColorPrefs[size_t(aID)];
+  if (aScheme == ColorScheme::Dark) {
+    nsAutoCString darkPrefName(prefName);
+    darkPrefName.Append(".dark");
+    if (NS_SUCCEEDED(GetPrefColor(darkPrefName.get(), aResult))) {
+      return NS_OK;
+    }
+  }
+  return GetPrefColor(prefName, aResult);
+}
+
+// All these routines will return NS_OK if they have a value,
+// in which case the nsLookAndFeel should use that value;
+// otherwise we'll return NS_ERROR_NOT_AVAILABLE, in which case, the
+// platform-specific nsLookAndFeel should use its own values instead.
+nsresult nsXPLookAndFeel::GetColorValue(ColorID aID, ColorScheme aScheme,
+                                        UseStandins aUseStandins,
+                                        nscolor& aResult) {
+  if (!sInitialized) {
+    Init();
+  }
+
+#ifdef DEBUG_SYSTEM_COLOR_USE
+  if (NS_SUCCEEDED(SystemColorUseDebuggingColor(aID, aResult))) {
+    return NS_OK;
+  }
+#endif
+
+  auto& cache = sColorCaches.Get(aScheme, aUseStandins);
+  if (const auto* cached = cache.Get(aID)) {
+    if (cached->isNothing()) {
+      return NS_ERROR_FAILURE;
+    }
+    aResult = cached->value();
+    return NS_OK;
+  }
+
+  // NOTE: Servo holds a lock and the main thread is paused, so writing to the
+  // global cache here is fine.
+  auto result = GetUncachedColor(aID, aScheme, aUseStandins);
+  cache.Insert(aID, result);
+  if (!result) {
+    return NS_ERROR_FAILURE;
+  }
+  aResult = *result;
+  return NS_OK;
+}
+
+Maybe<nscolor> nsXPLookAndFeel::GetUncachedColor(ColorID aID,
+                                                 ColorScheme aScheme,
+                                                 UseStandins aUseStandins) {
+  if (aUseStandins == UseStandins::Yes) {
+    return Some(GetStandinForNativeColor(aID, aScheme));
+  }
+  nscolor r;
+  if (NS_SUCCEEDED(GetColorFromPref(aID, aScheme, r))) {
+    return Some(r);
+  }
+  if (NS_SUCCEEDED(NativeGetColor(aID, aScheme, r))) {
+    if (gfxPlatform::GetCMSMode() == CMSMode::All && !IsSpecialColor(aID, r)) {
+      qcms_transform* transform = gfxPlatform::GetCMSInverseRGBTransform();
+      if (transform) {
+        uint8_t color[4];
+        color[0] = NS_GET_R(r);
+        color[1] = NS_GET_G(r);
+        color[2] = NS_GET_B(r);
+        color[3] = NS_GET_A(r);
+        qcms_transform_data(transform, color, color, 1);
+        r = NS_RGBA(color[0], color[1], color[2], color[3]);
+      }
+    }
+
+    return Some(r);
+  }
+  return Nothing();
+}
+
+nsresult nsXPLookAndFeel::GetIntValue(IntID aID, int32_t& aResult) {
+  if (!sInitialized) {
+    Init();
+  }
+
+  if (const auto* cached = sIntCache.Get(aID)) {
+    if (cached->isNothing()) {
+      return NS_ERROR_FAILURE;
+    }
+    aResult = cached->value();
+    return NS_OK;
+  }
+
+  if (NS_SUCCEEDED(Preferences::GetInt(sIntPrefs[size_t(aID)], &aResult))) {
+    sIntCache.Insert(aID, Some(aResult));
+    return NS_OK;
+  }
+
+  if (NS_FAILED(NativeGetInt(aID, aResult))) {
+    sIntCache.Insert(aID, Nothing());
+    return NS_ERROR_FAILURE;
+  }
+
+  sIntCache.Insert(aID, Some(aResult));
+  return NS_OK;
+}
+
+nsresult nsXPLookAndFeel::GetFloatValue(FloatID aID, float& aResult) {
+  if (!sInitialized) {
+    Init();
+  }
+
+  if (const auto* cached = sFloatCache.Get(aID)) {
+    if (cached->isNothing()) {
+      return NS_ERROR_FAILURE;
+    }
+    aResult = cached->value();
+    return NS_OK;
+  }
+
+  int32_t pref = 0;
+  if (NS_SUCCEEDED(Preferences::GetInt(sFloatPrefs[size_t(aID)], &pref))) {
+    aResult = float(pref) / 100.0f;
+    sFloatCache.Insert(aID, Some(aResult));
+    return NS_OK;
+  }
+
+  if (NS_FAILED(NativeGetFloat(aID, aResult))) {
+    sFloatCache.Insert(aID, Nothing());
+    return NS_ERROR_FAILURE;
+  }
+
+  sFloatCache.Insert(aID, Some(aResult));
+  return NS_OK;
+}
+
+bool nsXPLookAndFeel::LookAndFeelFontToStyle(const LookAndFeelFont& aFont,
+                                             nsString& aName,
+                                             gfxFontStyle& aStyle) {
+  if (!aFont.haveFont()) {
+    return false;
+  }
+  aName = aFont.name();
+  aStyle = gfxFontStyle();
+  aStyle.size = aFont.size();
+  aStyle.weight = FontWeight::FromInt(aFont.weight());
+  aStyle.style =
+      aFont.italic() ? FontSlantStyle::ITALIC : FontSlantStyle::NORMAL;
+  aStyle.systemFont = true;
+  return true;
+}
+
+widget::LookAndFeelFont nsXPLookAndFeel::StyleToLookAndFeelFont(
+    const nsAString& aName, const gfxFontStyle& aStyle) {
+  LookAndFeelFont font;
+  font.haveFont() = true;
+  font.name() = aName;
+  font.size() = aStyle.size;
+  font.weight() = aStyle.weight.ToFloat();
+  font.italic() = aStyle.style.IsItalic();
+  MOZ_ASSERT(aStyle.style.IsNormal() || aStyle.style.IsItalic(),
+             "Cannot handle oblique font style");
+#ifdef DEBUG
+  {
+    // Assert that all the remaining font style properties have their
+    // default values.
+    gfxFontStyle candidate = aStyle;
+    gfxFontStyle defaults{};
+    candidate.size = defaults.size;
+    candidate.weight = defaults.weight;
+    candidate.style = defaults.style;
+    MOZ_ASSERT(candidate.Equals(defaults),
+               "Some font style properties not supported");
+  }
+#endif
+  return font;
+}
+
+bool nsXPLookAndFeel::GetFontValue(FontID aID, nsString& aName,
+                                   gfxFontStyle& aStyle) {
+  if (const LookAndFeelFont* cached = sFontCache.Get(aID)) {
+    return LookAndFeelFontToStyle(*cached, aName, aStyle);
+  }
+
+  LookAndFeelFont font;
+  auto GetFontsFromPrefs = [&]() -> bool {
+    nsDependentCString pref(sFontPrefs[size_t(aID)]);
+    if (NS_FAILED(Preferences::GetString(pref.get(), aName))) {
+      return false;
+    }
+    font.haveFont() = true;
+    font.name() = aName;
+    font.size() = Preferences::GetFloat(nsAutoCString(pref + ".size"_ns).get());
+    // This is written this way rather than using the fallback so that an empty
+    // pref (such like the one about:config creates) doesn't cause system fonts
+    // to have zero-size.
+    if (font.size() < 1.0f) {
+      font.size() = StyleFONT_MEDIUM_PX;
+    }
+    font.weight() = Preferences::GetFloat(
+        nsAutoCString(pref + ".weight"_ns).get(), FontWeight::NORMAL.ToFloat());
+    font.italic() =
+        Preferences::GetBool(nsAutoCString(pref + ".italic"_ns).get());
+    return true;
+  };
+
+  if (GetFontsFromPrefs()) {
+    LookAndFeelFontToStyle(font, aName, aStyle);
+  } else if (NativeGetFont(aID, aName, aStyle)) {
+    font = StyleToLookAndFeelFont(aName, aStyle);
+  } else {
+    MOZ_ASSERT(!font.haveFont());
+  }
+  bool success = font.haveFont();
+  sFontCache.Insert(aID, std::move(font));
+  return success;
+}
+
+void nsXPLookAndFeel::RefreshImpl() {
+  // Wipe out our caches.
+  sColorCaches.Clear();
+  sFontCache.Clear();
+  sFloatCache.Clear();
+  sIntCache.Clear();
+
+  if (XRE_IsParentProcess()) {
+    nsLayoutUtils::RecomputeSmoothScrollDefault();
+    // Clear any cached FullLookAndFeel data, which is now invalid.
+    widget::RemoteLookAndFeel::ClearCachedData();
+  }
+}
+
+static bool sRecordedLookAndFeelTelemetry = false;
+
+void nsXPLookAndFeel::RecordTelemetry() {
+  if (!XRE_IsParentProcess()) {
+    return;
+  }
+
+  if (sRecordedLookAndFeelTelemetry) {
+    return;
+  }
+
+  sRecordedLookAndFeelTelemetry = true;
+
+  int32_t i;
+  Telemetry::ScalarSet(
+      Telemetry::ScalarID::WIDGET_DARK_MODE,
+      NS_SUCCEEDED(GetIntValue(IntID::SystemUsesDarkTheme, i)) && i != 0);
+
+  RecordLookAndFeelSpecificTelemetry();
+}
+
+namespace mozilla {
+
+bool LookAndFeel::sGlobalThemeChanged;
+static widget::ThemeChangeKind sGlobalThemeChangeKind{0};
+
+void LookAndFeel::NotifyChangedAllWindows(widget::ThemeChangeKind aKind) {
+  sGlobalThemeChanged = true;
+  sGlobalThemeChangeKind |= aKind;
+
+  if (nsCOMPtr<nsIObserverService> obs = services::GetObserverService()) {
+    const char16_t kind[] = {char16_t(aKind), 0};
+    obs->NotifyObservers(nullptr, "internal-look-and-feel-changed", kind);
+  }
+}
+
+void LookAndFeel::DoHandleGlobalThemeChange() {
+  MOZ_ASSERT(sGlobalThemeChanged);
+  sGlobalThemeChanged = false;
+  auto kind = std::exchange(sGlobalThemeChangeKind, widget::ThemeChangeKind(0));
+
+  // Tell the theme that it changed, so it can flush any handles to stale theme
+  // data.
+  //
+  // We can use the *DoNotUseDirectly functions directly here, because we want
+  // to notify all possible themes in a given process (but just once).
+  if (XRE_IsParentProcess() ||
+      !StaticPrefs::widget_non_native_theme_enabled()) {
+    if (nsCOMPtr<nsITheme> theme = do_GetNativeThemeDoNotUseDirectly()) {
+      theme->ThemeChanged();
+    }
+  }
+  if (nsCOMPtr<nsITheme> theme = do_GetBasicNativeThemeDoNotUseDirectly()) {
+    theme->ThemeChanged();
+  }
+
+  // Clear all cached LookAndFeel colors.
+  LookAndFeel::Refresh();
+
+  // Reset default background and foreground colors for the document since they
+  // may be using system colors, color scheme, etc.
+  PreferenceSheet::Refresh();
+
+  // Vector images (SVG) may be using theme colors so we discard all cached
+  // surfaces. (We could add a vector image only version of DiscardAll, but
+  // in bug 940625 we decided theme changes are rare enough not to bother.)
+  image::SurfaceCacheUtils::DiscardAll();
+
+  if (XRE_IsParentProcess()) {
+    dom::ContentParent::BroadcastThemeUpdate(kind);
+  }
+
+  nsContentUtils::AddScriptRunner(
+      NS_NewRunnableFunction("HandleGlobalThemeChange", [] {
+        if (nsCOMPtr<nsIObserverService> obs = services::GetObserverService()) {
+          obs->NotifyObservers(nullptr, "look-and-feel-changed", nullptr);
+        }
+      }));
+}
+
+#define BIT_FOR(_c) (1ull << size_t(ColorID::_c))
+
+// We want to use a non-native color scheme for the non-native theme (except in
+// high-contrast mode), so spoof some of the colors with stand-ins to prevent
+// lack of contrast.
+static constexpr std::bitset<size_t(ColorID::End)> sNonNativeThemeStandinColors{
+    // Used by default button styles.
+    BIT_FOR(Buttonface) | BIT_FOR(Buttontext) | BIT_FOR(MozButtonhoverface) |
+    BIT_FOR(MozButtonhovertext) | BIT_FOR(MozButtonactiveface) |
+    BIT_FOR(MozButtonactivetext) | BIT_FOR(MozButtondisabledface) |
+    BIT_FOR(Buttonborder) |
+    // Used by select elements.
+    BIT_FOR(MozCombobox) | BIT_FOR(MozComboboxtext) |
+    BIT_FOR(Threedlightshadow) |
+    // For symmetry with the above.
+    BIT_FOR(Threeddarkshadow) |
+    // Used by fieldset borders.
+    BIT_FOR(Threedface) |
+    // Used by input / textarea.
+    BIT_FOR(Field) | BIT_FOR(Fieldtext) |
+    // Used by disabled form controls.
+    BIT_FOR(MozDisabledfield) | BIT_FOR(Graytext) |
+    // Per spec, the following colors are deprecated, see
+    // https://drafts.csswg.org/css-color-4/#deprecated-system-colors
+    // should match ButtonFace:
+    BIT_FOR(Buttonhighlight) | BIT_FOR(Buttonshadow) | BIT_FOR(Threedface) |
+    // should match ButtonBorder:
+    BIT_FOR(Activeborder) | BIT_FOR(Inactiveborder) |
+    BIT_FOR(Threeddarkshadow) | BIT_FOR(Threedhighlight) |
+    BIT_FOR(Threedshadow) | BIT_FOR(Windowframe) |
+    // should match GrayText:
+    BIT_FOR(Inactivecaptiontext) |
+    // should match Canvas/Window:
+    BIT_FOR(Appworkspace) | BIT_FOR(Background) | BIT_FOR(Inactivecaption) |
+    BIT_FOR(Infobackground) | BIT_FOR(Menu) | BIT_FOR(Scrollbar) |
+    // should match CanvasText/WindowText:
+    BIT_FOR(Activecaption) | BIT_FOR(Captiontext) | BIT_FOR(Infotext) |
+    BIT_FOR(Menutext) |
+    // Some pages expect these to return windows-like colors, see bug 1773795.
+    // Also, per spec, these should match Canvas/CanvasText, see
+    // https://drafts.csswg.org/css-color-4/#valdef-color-window and
+    // https://drafts.csswg.org/css-color-4/#valdef-color-windowtext
+    BIT_FOR(Window) | BIT_FOR(Windowtext)};
+#undef BIT_FOR
+
+static bool ShouldUseStandinsForNativeColorForNonNativeTheme(
+    const dom::Document& aDoc, LookAndFeel::ColorID aColor,
+    const PreferenceSheet::Prefs& aPrefs) {
+  const bool shouldUseStandinsForColor = [&] {
+    if (sNonNativeThemeStandinColors[size_t(aColor)]) {
+      return true;
+    }
+    // There are platforms where we want the content-exposed accent color to be
+    // the windows blue rather than the system accent color, for now.
+    return !StaticPrefs::widget_non_native_theme_use_theme_accent() &&
+           (aColor == LookAndFeel::ColorID::Accentcolor ||
+            aColor == LookAndFeel::ColorID::Accentcolortext);
+  }();
+
+  return shouldUseStandinsForColor && aDoc.ShouldAvoidNativeTheme() &&
+         !aPrefs.NonNativeThemeShouldBeHighContrast();
+}
+
+bool LookAndFeel::IsDarkColor(nscolor aColor) {
+  // Given https://www.w3.org/TR/WCAG20/#contrast-ratiodef, this is the
+  // threshold that tells us whether contrast is better against white or black.
+  //
+  // Contrast ratio against black is: (L + 0.05) / 0.05
+  // Contrast ratio against white is: 1.05 / (L + 0.05)
+  //
+  // So the intersection is:
+  //
+  //   (L + 0.05) / 0.05 = 1.05 / (L + 0.05)
+  //
+  // And the solution to that equation is:
+  //
+  //   sqrt(1.05 * 0.05) - 0.05
+  //
+  // So we consider a color dark if the contrast is below this threshold, and
+  // it's at least half-opaque.
+  constexpr float kThreshold = 0.179129;
+  return NS_GET_A(aColor) > 127 &&
+         RelativeLuminanceUtils::Compute(aColor) < kThreshold;
+}
+
+ColorScheme LookAndFeel::ColorSchemeForStyle(
+    const dom::Document& aDoc, const StyleColorSchemeFlags& aFlags,
+    ColorSchemeMode aMode) {
+  const auto& prefs = PreferenceSheet::PrefsFor(aDoc);
+  StyleColorSchemeFlags style(aFlags);
+  if (!style) {
+    style._0 = aDoc.GetColorSchemeBits();
+  }
+  const bool supportsDark = bool(style & StyleColorSchemeFlags::DARK);
+  const bool supportsLight = bool(style & StyleColorSchemeFlags::LIGHT);
+  if (supportsLight && supportsDark) {
+    // Both color-schemes are explicitly supported, use the preferred one.
+    return aDoc.PreferredColorScheme();
+  }
+  if (supportsDark || supportsLight) {
+    // One color-scheme is explicitly supported and one isn't, so use the one
+    // the content supports.
+    return supportsDark ? ColorScheme::Dark : ColorScheme::Light;
+  }
+  // No value specified. Chrome docs, and forced-colors mode always supports
+  // both, so use the preferred color-scheme.
+  if (aMode == ColorSchemeMode::Preferred || aDoc.ChromeRulesEnabled() ||
+      !prefs.mUseDocumentColors) {
+    return aDoc.PreferredColorScheme();
+  }
+  // Otherwise default content to light.
+  return ColorScheme::Light;
+}
+
+LookAndFeel::ColorScheme LookAndFeel::ColorSchemeForFrame(
+    const nsIFrame* aFrame, ColorSchemeMode aMode) {
+  return ColorSchemeForStyle(*aFrame->PresContext()->Document(),
+                             aFrame->StyleUI()->mColorScheme.bits, aMode);
+}
+
+// static
+Maybe<nscolor> LookAndFeel::GetColor(ColorID aId, ColorScheme aScheme,
+                                     UseStandins aUseStandins) {
+  nscolor result;
+  nsresult rv = nsLookAndFeel::GetInstance()->GetColorValue(
+      aId, aScheme, aUseStandins, result);
+  if (NS_FAILED(rv)) {
+    return Nothing();
+  }
+  return Some(result);
+}
+
+// Returns whether there is a CSS color name for this color.
+static bool ColorIsCSSAccessible(LookAndFeel::ColorID aId) {
+  using ColorID = LookAndFeel::ColorID;
+
+  switch (aId) {
+    case ColorID::TextSelectDisabledBackground:
+    case ColorID::TextSelectAttentionBackground:
+    case ColorID::TextSelectAttentionForeground:
+    case ColorID::TextHighlightBackground:
+    case ColorID::TextHighlightForeground:
+    case ColorID::ThemedScrollbar:
+    case ColorID::ThemedScrollbarInactive:
+    case ColorID::ThemedScrollbarThumb:
+    case ColorID::ThemedScrollbarThumbActive:
+    case ColorID::ThemedScrollbarThumbInactive:
+    case ColorID::ThemedScrollbarThumbHover:
+    case ColorID::IMERawInputBackground:
+    case ColorID::IMERawInputForeground:
+    case ColorID::IMERawInputUnderline:
+    case ColorID::IMESelectedRawTextBackground:
+    case ColorID::IMESelectedRawTextForeground:
+    case ColorID::IMESelectedRawTextUnderline:
+    case ColorID::IMEConvertedTextBackground:
+    case ColorID::IMEConvertedTextForeground:
+    case ColorID::IMEConvertedTextUnderline:
+    case ColorID::IMESelectedConvertedTextBackground:
+    case ColorID::IMESelectedConvertedTextForeground:
+    case ColorID::IMESelectedConvertedTextUnderline:
+    case ColorID::SpellCheckerUnderline:
+      return false;
+    default:
+      break;
+  }
+
+  return true;
+}
+
+LookAndFeel::UseStandins LookAndFeel::ShouldUseStandins(
+    const dom::Document& aDoc, ColorID aId) {
+  const auto& prefs = PreferenceSheet::PrefsFor(aDoc);
+  if (ShouldUseStandinsForNativeColorForNonNativeTheme(aDoc, aId, prefs)) {
+    return UseStandins::Yes;
+  }
+  if (prefs.mUseStandins && ColorIsCSSAccessible(aId)) {
+    return UseStandins::Yes;
+  }
+  return UseStandins::No;
+}
+
+Maybe<nscolor> LookAndFeel::GetColor(ColorID aId, const nsIFrame* aFrame) {
+  const auto* doc = aFrame->PresContext()->Document();
+  return GetColor(aId, ColorSchemeForFrame(aFrame),
+                  ShouldUseStandins(*doc, aId));
+}
+
+// static
+nsresult LookAndFeel::GetInt(IntID aID, int32_t* aResult) {
+  return nsLookAndFeel::GetInstance()->GetIntValue(aID, *aResult);
+}
+
+// static
+nsresult LookAndFeel::GetFloat(FloatID aID, float* aResult) {
+  return nsLookAndFeel::GetInstance()->GetFloatValue(aID, *aResult);
+}
+
+// static
+bool LookAndFeel::GetFont(FontID aID, nsString& aName, gfxFontStyle& aStyle) {
+  return nsLookAndFeel::GetInstance()->GetFontValue(aID, aName, aStyle);
+}
+
+// static
+char16_t LookAndFeel::GetPasswordCharacter() {
+  return nsLookAndFeel::GetInstance()->GetPasswordCharacterImpl();
+}
+
+// static
+bool LookAndFeel::GetEchoPassword() {
+  if (StaticPrefs::editor_password_mask_delay() >= 0) {
+    return StaticPrefs::editor_password_mask_delay() > 0;
+  }
+  return nsLookAndFeel::GetInstance()->GetEchoPasswordImpl();
+}
+
+// static
+uint32_t LookAndFeel::GetPasswordMaskDelay() {
+  int32_t delay = StaticPrefs::editor_password_mask_delay();
+  if (delay < 0) {
+    return nsLookAndFeel::GetInstance()->GetPasswordMaskDelayImpl();
+  }
+  return delay;
+}
+
+bool LookAndFeel::DrawInTitlebar() {
+  switch (StaticPrefs::browser_tabs_inTitlebar()) {
+    case 0:
+      return false;
+    case 1:
+      return true;
+    default:
+      break;
+  }
+  return nsLookAndFeel::GetInstance()->GetDefaultDrawInTitlebar();
+}
+
+LookAndFeel::TitlebarAction LookAndFeel::GetTitlebarAction(
+    TitlebarEvent aEvent) {
+  return nsLookAndFeel::GetInstance()->GetTitlebarAction(aEvent);
+}
+
+void LookAndFeel::GetThemeInfo(nsACString& aOut) {
+  nsLookAndFeel::GetInstance()->GetThemeInfo(aOut);
+}
+
+uint32_t LookAndFeel::GetMenuAccessKey() {
+  return StaticPrefs::ui_key_menuAccessKey();
+}
+
+Modifiers LookAndFeel::GetMenuAccessKeyModifiers() {
+  switch (GetMenuAccessKey()) {
+    case dom::KeyboardEvent_Binding::DOM_VK_SHIFT:
+      return MODIFIER_SHIFT;
+    case dom::KeyboardEvent_Binding::DOM_VK_CONTROL:
+      return MODIFIER_CONTROL;
+    case dom::KeyboardEvent_Binding::DOM_VK_ALT:
+      return MODIFIER_ALT;
+    case dom::KeyboardEvent_Binding::DOM_VK_META:
+    case dom::KeyboardEvent_Binding::DOM_VK_WIN:
+      return MODIFIER_META;
+    default:
+      return 0;
+  }
+}
+
+// static
+void LookAndFeel::Refresh() {
+  nsLookAndFeel::GetInstance()->RefreshImpl();
+  widget::Theme::LookAndFeelChanged();
+}
+
+// static
+void LookAndFeel::NativeInit() { nsLookAndFeel::GetInstance()->NativeInit(); }
+
+// static
+void LookAndFeel::SetData(widget::FullLookAndFeel&& aTables) {
+  nsLookAndFeel::GetInstance()->SetDataImpl(std::move(aTables));
+}
+
+}  // namespace mozilla
diff --git a/widget/nsXPLookAndFeel.h b/widget/nsXPLookAndFeel.h
new file mode 100644
index 0000000000..0f308f6935
--- /dev/null
+++ b/widget/nsXPLookAndFeel.h
@@ -0,0 +1,96 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsXPLookAndFeel
+#define __nsXPLookAndFeel
+
+#include "mozilla/Maybe.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/widget/LookAndFeelTypes.h"
+#include "nsTArray.h"
+
+class nsLookAndFeel;
+
+class nsXPLookAndFeel : public mozilla::LookAndFeel {
+ public:
+  using FullLookAndFeel = mozilla::widget::FullLookAndFeel;
+  using LookAndFeelFont = mozilla::widget::LookAndFeelFont;
+
+  virtual ~nsXPLookAndFeel();
+
+  static nsXPLookAndFeel* GetInstance();
+  static void Shutdown();
+
+  void Init();
+
+  // Gets the pref name for a given color, just for debugging purposes.
+  static const char* GetColorPrefName(ColorID);
+
+  // These functions will return a value specified by an override pref, if it
+  // exists, and otherwise will call into the NativeGetXxx function to get the
+  // platform-specific value.
+  //
+  // NS_ERROR_NOT_AVAILABLE is returned if there is neither an override pref or
+  // a platform-specific value.
+  nsresult GetColorValue(ColorID, ColorScheme, UseStandins, nscolor& aResult);
+  nsresult GetIntValue(IntID aID, int32_t& aResult);
+  nsresult GetFloatValue(FloatID aID, float& aResult);
+  // Same, but returns false if there is no platform-specific value.
+  // (There are no override prefs for font values.)
+  bool GetFontValue(FontID aID, nsString& aName, gfxFontStyle& aStyle);
+
+  virtual nsresult NativeGetInt(IntID aID, int32_t& aResult) = 0;
+  virtual nsresult NativeGetFloat(FloatID aID, float& aResult) = 0;
+  virtual nsresult NativeGetColor(ColorID, ColorScheme, nscolor& aResult) = 0;
+  virtual bool NativeGetFont(FontID aID, nsString& aName,
+                             gfxFontStyle& aStyle) = 0;
+
+  virtual void RefreshImpl();
+
+  virtual char16_t GetPasswordCharacterImpl() { return char16_t('*'); }
+
+  virtual bool GetEchoPasswordImpl() { return false; }
+
+  virtual uint32_t GetPasswordMaskDelayImpl() { return 600; }
+
+  virtual bool GetDefaultDrawInTitlebar() { return true; }
+
+  virtual TitlebarAction GetTitlebarAction(TitlebarEvent aEvent) {
+    return TitlebarAction::None;
+  }
+
+  static bool LookAndFeelFontToStyle(const LookAndFeelFont&, nsString& aName,
+                                     gfxFontStyle&);
+  static LookAndFeelFont StyleToLookAndFeelFont(const nsAString& aName,
+                                                const gfxFontStyle&);
+
+  virtual void SetDataImpl(FullLookAndFeel&& aTables) {}
+
+  virtual void NativeInit() = 0;
+
+  virtual void GetThemeInfo(nsACString&) {}
+
+ protected:
+  nsXPLookAndFeel() = default;
+
+  static nscolor GetStandinForNativeColor(ColorID, ColorScheme);
+
+  // A platform-agnostic dark-color scheme, for platforms where we don't have
+  // "native" dark colors, like Windows and Android.
+  static mozilla::Maybe<nscolor> GenericDarkColor(ColorID);
+  mozilla::Maybe<nscolor> GetUncachedColor(ColorID, ColorScheme, UseStandins);
+
+  void RecordTelemetry();
+  virtual void RecordLookAndFeelSpecificTelemetry() {}
+
+  static void OnPrefChanged(const char* aPref, void* aClosure);
+
+  static bool sInitialized;
+
+  static nsXPLookAndFeel* sInstance;
+  static bool sShutdown;
+};
+
+#endif
diff --git a/widget/reftests/664925.xhtml b/widget/reftests/664925.xhtml
new file mode 100644
index 0000000000..b4a11a7386
--- /dev/null
+++ b/widget/reftests/664925.xhtml
@@ -0,0 +1 @@
+<html xmlns="http://www.w3.org/1999/xhtml"><div><td style="-moz-appearance: progressbar;"></td></div></html>
diff --git a/widget/reftests/meter-fallback-default-style-ref.html b/widget/reftests/meter-fallback-default-style-ref.html
new file mode 100644
index 0000000000..cf6c2e521e
--- /dev/null
+++ b/widget/reftests/meter-fallback-default-style-ref.html
@@ -0,0 +1,57 @@
+<!DOCTYPE html>
+<html>
+  <style>
+    div.meter-element {
+      /**
+       * The purpose of this test is to not show the native style.
+       * -moz-appearance: meterbar;
+       */
+      display: inline-block;
+      height: 1em;
+      width: 5em;
+      vertical-align: -0.2em;
+
+      background: linear-gradient(#e6e6e6, #e6e6e6, #eeeeee 20%, #cccccc 45%, #cccccc 55%);
+    }
+
+    div.meter-bar {
+      /**
+       * The purpose of this test is to not show the native style.
+       * -moz-appearance: meterchunk;
+       */
+
+      height: 100%;
+      width: 100%;
+
+      background: linear-gradient(#ad7, #ad7, #cea 20%, #7a3 45%, #7a3 55%);
+    }
+
+    div.meter-element { padding: 5px; }
+    body > div:nth-child(1)  { -moz-appearance: none; }
+    body > div:nth-child(2) > .meter-bar { -moz-appearance: none; }
+    body > div:nth-child(3)  { background: red; }
+    body > div:nth-child(4) > .meter-bar { background: red; }
+    body > div:nth-child(5)  { border: 2px solid red; }
+    body > div:nth-child(6) > .meter-bar { border: 5px solid red; width: calc(100% - 10px); }
+  </style>
+  <body>
+    <div class="meter-element">
+      <div class="meter-bar"></div>
+    </div>
+    <div class="meter-element">
+      <div class="meter-bar"></div>
+    </div>
+    <div class="meter-element">
+      <div class="meter-bar"></div>
+    </div>
+    <div class="meter-element">
+      <div class="meter-bar"></div>
+    </div>
+    <div class="meter-element">
+      <div class="meter-bar"></div>
+    </div>
+    <div class="meter-element">
+      <div class="meter-bar"></div>
+    </div>
+  </body>
+</html>
diff --git a/widget/reftests/meter-fallback-default-style.html b/widget/reftests/meter-fallback-default-style.html
new file mode 100644
index 0000000000..c59fc265e4
--- /dev/null
+++ b/widget/reftests/meter-fallback-default-style.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html>
+  <style>
+    meter { padding: 5px }
+    body > meter:nth-child(1) { -moz-appearance: none; }
+    body > meter:nth-child(2)::-moz-meter-bar { -moz-appearance: none; }
+    body > meter:nth-child(3) { background: red; }
+    body > meter:nth-child(4)::-moz-meter-bar { background: red; }
+    body > meter:nth-child(5) { border: 2px solid red; }
+    body > meter:nth-child(6) { overflow: visible; }
+    body > meter:nth-child(6)::-moz-meter-bar { border: 5px solid red; }
+  </style>
+  <body>
+    <meter value=1></meter>
+    <meter value=1></meter>
+    <meter value=1></meter>
+    <meter value=1></meter>
+    <meter value=1></meter>
+    <meter value=1></meter>
+  </body>
+</html>
diff --git a/widget/reftests/meter-native-style-ref.html b/widget/reftests/meter-native-style-ref.html
new file mode 100644
index 0000000000..f54ec0bbac
--- /dev/null
+++ b/widget/reftests/meter-native-style-ref.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+  <body>
+    <!-- Empty meter, no bar. -->
+    <meter></meter>
+    <!-- Full meter green colored. -->
+    <meter min=0 low=0 high=1 optimum=2 max=10 value=10></meter>
+    <!-- Full meter orange colored. -->
+    <meter min=0 low=0 high=1 optimum=1 max=10 value=10></meter>
+    <!-- Full meter red colored. -->
+    <meter min=0 low=1 high=2 optimum=0 max=10 value=10></meter>
+    <!-- Half-empty orange colored. -->
+    <meter min=0 low=0 high=1 optimum=0 max=10 value=5></meter>
+    <!-- Half-empty orange colored. -->
+    <meter min=0 low=0 high=1 optimum=0 max=10 value=5></meter>
+    <!-- With RTL, the bar should begin on the right. -->
+    <meter style="transform: scale(-1, 1);" value=0.5></meter>
+  </body>
+</html>
diff --git a/widget/reftests/meter-native-style.html b/widget/reftests/meter-native-style.html
new file mode 100644
index 0000000000..91342772fe
--- /dev/null
+++ b/widget/reftests/meter-native-style.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+  <body>
+    <meter vaue=0></meter>
+    <!-- Should be green. -->
+    <meter min=0 low=0 high=10 optimum=10 max=10 value=10></meter>
+    <!-- Should be orange. -->
+    <meter min=0 low=9 high=10 optimum=8 max=10 value=10></meter>
+    <!-- Should be red. -->
+    <meter min=0 low=8 high=9 optimum=0 max=10 value=10></meter>
+    <!-- Half-full orange. -->
+    <meter min=0 low=3 high=4 optimum=4 max=10 value=5></meter>
+    <!-- Half-full orange. -->
+    <meter min=0 low=9 high=10 optimum=10 max=10 value=5></meter>
+    <!-- Test RTL -->
+    <meter dir='rtl' value=0.5></meter>
+  </body>
+</html>
diff --git a/widget/reftests/meter-vertical-native-style-ref.html b/widget/reftests/meter-vertical-native-style-ref.html
new file mode 100644
index 0000000000..e771d3fd76
--- /dev/null
+++ b/widget/reftests/meter-vertical-native-style-ref.html
@@ -0,0 +1,14 @@
+<html>
+  <style>
+    meter:nth-child(1) { transform: rotate(-90deg) translate(-2em, -2em); }
+    meter:nth-child(2) { transform: rotate(-90deg) translate(-2em, -6em); }
+    meter:nth-child(3) { transform: rotate(-90deg) translate(-2em, -10em); }
+    meter:nth-child(4) { transform: rotate(-90deg) translate(-2em, -14em); }
+    meter:nth-child(5) { transform: rotate(-90deg) translate(-2em, -18em); }
+    meter:nth-child(6) { transform: rotate(-90deg) translate(-2em, -22em); }
+    meter:nth-child(7) { transform: rotate(-90deg) translate(-2em, -26em); }
+  </style>
+<body>
+<meter></meter><meter min=0 low=0 high=1 optimum=2 max=10 value=10></meter><meter min=0 low=0 high=1 optimum=1 max=10 value=10></meter><meter min=0 low=1 high=2 optimum=0 max=10 value=10></meter><meter min=0 low=0 high=1 optimum=0 max=10 value=5></meter><meter min=0 low=0 high=1 optimum=0 max=10 value=5></meter><meter value=0.5></meter>
+</body>
+</html>
diff --git a/widget/reftests/meter-vertical-native-style.html b/widget/reftests/meter-vertical-native-style.html
new file mode 100644
index 0000000000..ca0ca1b933
--- /dev/null
+++ b/widget/reftests/meter-vertical-native-style.html
@@ -0,0 +1,13 @@
+<html>
+  <style>
+    meter { -moz-orient: vertical; }
+  </style>
+  <body>
+<!-- For some reasons, the ref has a small offset when there are spaces between meters.
+     Given that we don't want to test transform and even a perfect match but just
+     the general rendering, we are going to keep this dirty test.
+     It's very similar to the non-vertical test with a difference, for the RTL: RTL
+     does not apply for vertical meters. -->
+<meter vaue=0></meter><meter min=0 low=0 high=10 optimum=10 max=10 value=10></meter><meter min=0 low=9 high=10 optimum=8 max=10 value=10></meter><meter min=0 low=8 high=9 optimum=0 max=10 value=10></meter><meter min=0 low=3 high=4 optimum=4 max=10 value=5></meter><meter min=0 low=9 high=10 optimum=10 max=10 value=5></meter><meter value=0.5 dir=rtl></meter>
+  </body>
+</html>
diff --git a/widget/reftests/progressbar-fallback-default-style-ref.html b/widget/reftests/progressbar-fallback-default-style-ref.html
new file mode 100644
index 0000000000..22950ec583
--- /dev/null
+++ b/widget/reftests/progressbar-fallback-default-style-ref.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<html>
+  <link rel='stylesheet' href='resource://reftest/progress.css'>
+  <style>
+    div.progress-element { padding: 5px; }
+    body > div:nth-child(1)  { -moz-appearance: none; }
+    body > div:nth-child(2) > .progress-bar { -moz-appearance: none; }
+    body > div:nth-child(3)  { background-color: red; }
+    body > div:nth-child(4) > .progress-bar { background-color: red; }
+    body > div:nth-child(5)  { border: 2px solid red; }
+    body > div:nth-child(6) > .progress-bar { border: 5px solid red; }
+  </style>
+  <body>
+    <div class="progress-element">
+      <div class="progress-bar"></div>
+    </div>
+    <div class="progress-element">
+      <div class="progress-bar"></div>
+    </div>
+    <div class="progress-element">
+      <div class="progress-bar"></div>
+    </div>
+    <div class="progress-element">
+      <div class="progress-bar"></div>
+    </div>
+    <div class="progress-element">
+      <div class="progress-bar"></div>
+    </div>
+    <div class="progress-element">
+      <div class="progress-bar"></div>
+    </div>
+  </body>
+</html>
diff --git a/widget/reftests/progressbar-fallback-default-style.html b/widget/reftests/progressbar-fallback-default-style.html
new file mode 100644
index 0000000000..7594e65556
--- /dev/null
+++ b/widget/reftests/progressbar-fallback-default-style.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html>
+  <style>
+    progress { padding: 5px }
+    body > progress:nth-child(1) { -moz-appearance: none; }
+    body > progress:nth-child(2)::-moz-progress-bar { -moz-appearance: none; }
+    body > progress:nth-child(3) { background-color: red; }
+    body > progress:nth-child(4)::-moz-progress-bar { background-color: red; }
+    body > progress:nth-child(5) { border: 2px solid red; }
+    body > progress:nth-child(6)::-moz-progress-bar { border: 5px solid red; }
+  </style>
+  <body>
+    <progress></progress>
+    <progress></progress>
+    <progress></progress>
+    <progress></progress>
+    <progress></progress>
+    <progress></progress>
+  </body>
+</html>
diff --git a/widget/reftests/reftest.list b/widget/reftests/reftest.list
new file mode 100644
index 0000000000..dc788a31aa
--- /dev/null
+++ b/widget/reftests/reftest.list
@@ -0,0 +1,9 @@
+== progressbar-fallback-default-style.html progressbar-fallback-default-style-ref.html
+fuzzy(0-31,0-67) == meter-native-style.html meter-native-style-ref.html
+fuzzy(0-11,0-342) == meter-vertical-native-style.html meter-vertical-native-style-ref.html # dithering
+== meter-fallback-default-style.html meter-fallback-default-style-ref.html
+load 664925.xhtml
+pref(apz.allow_zooming,true) pref(ui.useOverlayScrollbars,0) skip-if(!cocoaWidget) != scaled-scrollbar.html about:blank
+
+# Test that scrollbar buttons are inhibited on Linux using the non-native theme.
+skip-if(!gtkWidget) pref(widget.non-native-theme.enabled,true) test-pref(ui.scrollArrowStyle,4097) ref-pref(ui.scrollArrowStyle,0) == scrollbar-buttons.html scrollbar-buttons.html
diff --git a/widget/reftests/scaled-scrollbar.html b/widget/reftests/scaled-scrollbar.html
new file mode 100644
index 0000000000..f94df78420
--- /dev/null
+++ b/widget/reftests/scaled-scrollbar.html
@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+<html reftest-resolution="2.0" style="scrollbar-width: none;">
+<div style="overflow: scroll; width: 300px; height: 300px">
+ <div style="width: 1000px; height: 1000px"></div>
+</div>
+</html>
diff --git a/widget/reftests/scrollbar-buttons.html b/widget/reftests/scrollbar-buttons.html
new file mode 100644
index 0000000000..d54218272d
--- /dev/null
+++ b/widget/reftests/scrollbar-buttons.html
@@ -0,0 +1,4 @@
+<!DOCTYPE html>
+<div style="width: 200px; height: 200px; overflow: scroll;">
+  <div style="width: 400px; height: 400px;"></div>
+</div>
diff --git a/widget/tests/TestChromeMargin.cpp b/widget/tests/TestChromeMargin.cpp
new file mode 100644
index 0000000000..0eed86b208
--- /dev/null
+++ b/widget/tests/TestChromeMargin.cpp
@@ -0,0 +1,130 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* This tests the margin parsing functionality in nsAttrValue.cpp, which
+ * is accessible via nsContentUtils, and is used in setting chromemargins
+ * to widget windows. It's located here due to linking issues in the
+ * content directory.
+ */
+
+/* This test no longer compiles now that we've removed nsIContentUtils (bug
+ * 647273).  We need to be internal code in order to include nsContentUtils.h,
+ * but defining MOZILLA_INTERNAL_API is not enough to make us internal.
+ */
+
+#include "TestHarness.h"
+
+#ifndef MOZILLA_INTERNAL_API
+#  error This test needs MOZILLA_INTERNAL_API (see bug 652123)
+#endif
+
+#include "nscore.h"
+#include "nsContentUtils.h"
+#include "nsString.h"
+
+struct DATA {
+  bool shouldfail;
+  const char* margins;
+  int top;
+  int right;
+  int bottom;
+  int left;
+};
+
+const bool SHOULD_FAIL = true;
+const int SHOULD_PASS = false;
+
+const DATA Data[] = {
+    {SHOULD_FAIL, "", 1, 2, 3, 4},
+    {SHOULD_FAIL, "1,0,0,0", 1, 2, 3, 4},
+    {SHOULD_FAIL, "1,2,0,0", 1, 2, 3, 4},
+    {SHOULD_FAIL, "1,2,3,0", 1, 2, 3, 4},
+    {SHOULD_FAIL, "4,3,2,1", 1, 2, 3, 4},
+    {SHOULD_FAIL, "azsasdasd", 0, 0, 0, 0},
+    {SHOULD_FAIL, ",azsasdasd", 0, 0, 0, 0},
+    {SHOULD_FAIL, "           ", 1, 2, 3, 4},
+    {SHOULD_FAIL,
+     "azsdfsdfsdfsdfsdfsasdasd,asdasdasdasdasdasd,asdadasdasd,asdasdasdasd", 0,
+     0, 0, 0},
+    {SHOULD_FAIL, "as,as,as,as", 0, 0, 0, 0},
+    {SHOULD_FAIL, "0,0,0", 0, 0, 0, 0},
+    {SHOULD_FAIL, "0,0", 0, 0, 0, 0},
+    {SHOULD_FAIL, "4.6,1,1,1", 0, 0, 0, 0},
+    {SHOULD_FAIL, ",,,,", 0, 0, 0, 0},
+    {SHOULD_FAIL, "1, , , ,", 0, 0, 0, 0},
+    {SHOULD_FAIL, "1, , ,", 0, 0, 0, 0},
+    {SHOULD_FAIL, "@!@%^&^*()", 1, 2, 3, 4},
+    {SHOULD_PASS, "4,3,2,1", 4, 3, 2, 1},
+    {SHOULD_PASS, "-4,-3,-2,-1", -4, -3, -2, -1},
+    {SHOULD_PASS, "10000,3,2,1", 10000, 3, 2, 1},
+    {SHOULD_PASS, "4  , 3   , 2 , 1", 4, 3, 2, 1},
+    {SHOULD_PASS, "4,    3   ,2,1", 4, 3, 2, 1},
+    {SHOULD_FAIL, "4,3,2,10000000000000 --", 4, 3, 2, 10000000000000},
+    {SHOULD_PASS, "4,3,2,1000", 4, 3, 2, 1000},
+    {SHOULD_PASS, "2147483647,3,2,1000", 2147483647, 3, 2, 1000},
+    {SHOULD_PASS, "2147483647,2147483647,2147483647,2147483647", 2147483647,
+     2147483647, 2147483647, 2147483647},
+    {SHOULD_PASS, "-2147483647,3,2,1000", -2147483647, 3, 2, 1000},
+    {SHOULD_FAIL, "2147483648,3,2,1000", 1, 3, 2, 1000},
+    {0, nullptr, 0, 0, 0, 0}};
+
+void DoAttrValueTest() {
+  int idx = -1;
+  bool didFail = false;
+  while (Data[++idx].margins) {
+    nsAutoString str;
+    str.AssignLiteral(Data[idx].margins);
+    nsIntMargin values(99, 99, 99, 99);
+    bool result = nsContentUtils::ParseIntMarginValue(str, values);
+
+    // if the parse fails
+    if (!result) {
+      if (Data[idx].shouldfail) continue;
+      fail(Data[idx].margins);
+      didFail = true;
+      printf("*1\n");
+      continue;
+    }
+
+    if (Data[idx].shouldfail) {
+      if (Data[idx].top == values.top && Data[idx].right == values.right &&
+          Data[idx].bottom == values.bottom && Data[idx].left == values.left) {
+        // not likely
+        fail(Data[idx].margins);
+        didFail = true;
+        printf("*2\n");
+        continue;
+      }
+      // good failure, parse failed and that's what we expected.
+      continue;
+    }
+#if 0
+    printf("%d==%d %d==%d %d==%d %d==%d\n",
+      Data[idx].top, values.top,
+      Data[idx].right, values.right,
+      Data[idx].bottom, values.bottom,
+      Data[idx].left, values.left);
+#endif
+    if (Data[idx].top == values.top && Data[idx].right == values.right &&
+        Data[idx].bottom == values.bottom && Data[idx].left == values.left) {
+      // good parse results
+      continue;
+    } else {
+      fail(Data[idx].margins);
+      didFail = true;
+      printf("*3\n");
+      continue;
+    }
+  }
+
+  if (!didFail) passed("nsAttrValue margin parsing tests passed.");
+}
+
+int main(int argc, char** argv) {
+  ScopedXPCOM xpcom("");
+  if (xpcom.failed()) return 1;
+  DoAttrValueTest();
+  return 0;
+}
diff --git a/widget/tests/browser/browser.toml b/widget/tests/browser/browser.toml
new file mode 100644
index 0000000000..506fe1a998
--- /dev/null
+++ b/widget/tests/browser/browser.toml
@@ -0,0 +1,90 @@
+[DEFAULT]
+skip-if = ["os == 'android'"]
+
+["browser_test_AZERTY_digit_shortcut.js"]
+skip-if = ["os == 'linux'"] # Linux build has not implemented sendNativeKeyEvent yet
+
+["browser_test_ContentCache.js"]
+
+["browser_test_InputContextURI.js"]
+
+["browser_test_clipboard_contextmenu.js"]
+
+["browser_test_clipboardcache.js"]
+skip-if = [
+  "os == 'win' && bits == 32 && !debug", # Bug 1759422
+  "os == 'linux'", # Bug 1792749
+]
+
+["browser_test_fullscreen_size.js"]
+
+["browser_test_ime_state_in_contenteditable_on_focus_move_in_remote_content.js"]
+support-files = [
+  "file_ime_state_tests.html",
+  "../file_ime_state_test_helper.js",
+  "../file_test_ime_state_on_focus_move.js",
+]
+
+["browser_test_ime_state_in_contenteditable_on_readonly_change_in_remote_content.js"]
+support-files = [
+  "file_ime_state_tests.html",
+  "../file_ime_state_test_helper.js",
+  "../file_test_ime_state_in_contenteditable_on_readonly_change.js",
+]
+
+["browser_test_ime_state_in_designMode_on_focus_move_in_remote_content.js"]
+support-files = [
+  "file_ime_state_tests.html",
+  "../file_ime_state_test_helper.js",
+  "../file_test_ime_state_on_focus_move.js",
+]
+
+["browser_test_ime_state_in_plugin_in_remote_content.js"]
+support-files = ["../file_ime_state_test_helper.js"]
+
+["browser_test_ime_state_in_text_control_on_reframe_in_remote_content.js"]
+support-files = [
+  "../file_ime_state_test_helper.js",
+  "../file_test_ime_state_in_text_control_on_reframe.js",
+]
+
+["browser_test_ime_state_on_editable_state_change_in_remote_content.js"]
+support-files = ["../file_ime_state_test_helper.js"]
+
+["browser_test_ime_state_on_focus_move_in_remote_content.js"]
+support-files = [
+  "file_ime_state_tests.html",
+  "../file_ime_state_test_helper.js",
+  "../file_test_ime_state_on_focus_move.js",
+]
+
+["browser_test_ime_state_on_input_type_change_in_remote_content.js"]
+skip-if = ["true"] # Bug 1817704
+support-files = [
+  "file_ime_state_tests.html",
+  "../file_ime_state_test_helper.js",
+  "../file_test_ime_state_on_input_type_change.js",
+]
+
+["browser_test_ime_state_on_readonly_change_in_remote_content.js"]
+support-files = [
+  "file_ime_state_tests.html",
+  "../file_ime_state_test_helper.js",
+  "../file_test_ime_state_on_readonly_change.js",
+]
+
+["browser_test_scrollbar_colors.js"]
+skip-if = ["os == 'linux'"] # bug 1460109
+support-files = ["helper_scrollbar_colors.html"]
+
+["browser_test_swipe_gesture.js"]
+skip-if = [
+  "win11_2009 && bits == 32 && !debug", # Bug 1759422
+  "verify", # Bug 1800022
+  "os == 'linux'", # Bug 1784772
+]
+support-files = [
+  "helper_swipe_gesture.html",
+  "!/gfx/layers/apz/test/mochitest/apz_test_native_event_utils.js",
+  "!/gfx/layers/apz/test/mochitest/apz_test_utils.js",
+]
diff --git a/widget/tests/browser/browser_test_AZERTY_digit_shortcut.js b/widget/tests/browser/browser_test_AZERTY_digit_shortcut.js
new file mode 100644
index 0000000000..ef5112ac01
--- /dev/null
+++ b/widget/tests/browser/browser_test_AZERTY_digit_shortcut.js
@@ -0,0 +1,84 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function () {
+  let tabs = [];
+  for (let i = 0; i < 10; i++) {
+    const tab = BrowserTestUtils.addTab(gBrowser);
+    tabs.push(tab);
+  }
+  const kIsMac = AppConstants.platform == "macosx";
+
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/browser/toolkit/content/tests/browser/file_empty.html",
+    async function (browser) {
+      let NativeKeyConstants = {};
+      Services.scriptloader.loadSubScript(
+        "chrome://mochikit/content/tests/SimpleTest/NativeKeyCodes.js",
+        NativeKeyConstants
+      );
+
+      function promiseSynthesizeAccelHyphenMinusWithAZERTY() {
+        return new Promise(resolve =>
+          EventUtils.synthesizeNativeKey(
+            EventUtils.KEYBOARD_LAYOUT_FRENCH_PC,
+            kIsMac
+              ? NativeKeyConstants.MAC_VK_ANSI_6
+              : NativeKeyConstants.WIN_VK_6,
+            { accelKey: true },
+            kIsMac ? "-" : "",
+            kIsMac ? "-" : "",
+            resolve
+          )
+        );
+      }
+
+      async function waitForCondition(aFunc) {
+        for (let i = 0; i < 60; i++) {
+          await new Promise(resolve =>
+            requestAnimationFrame(() => requestAnimationFrame(resolve))
+          );
+          if (aFunc(ZoomManager.getFullZoomForBrowser(browser))) {
+            return true;
+          }
+        }
+        return false;
+      }
+
+      const minZoomLevel = ZoomManager.MIN;
+      while (true) {
+        const currentZoom = ZoomManager.getFullZoomForBrowser(browser);
+        if (minZoomLevel == currentZoom) {
+          break;
+        }
+        info(`Trying to zoom out: ${currentZoom}`);
+        await promiseSynthesizeAccelHyphenMinusWithAZERTY();
+        if (!(await waitForCondition(aZoomLevel => aZoomLevel < currentZoom))) {
+          ok(false, `Failed to zoom out from ${currentZoom}`);
+          return;
+        }
+      }
+
+      await promiseSynthesizeAccelHyphenMinusWithAZERTY();
+      await waitForCondition(() => false);
+      is(
+        gBrowser.selectedBrowser,
+        browser,
+        "Tab shouldn't be changed by Ctrl+- of AZERTY keyboard layout"
+      );
+      // Reset the zoom before going to the next test.
+      EventUtils.synthesizeKey("0", { accelKey: true });
+      await waitForCondition(aZoomLevel => aZoomLevel == 1);
+    }
+  );
+
+  while (tabs.length) {
+    await new Promise(resolve => {
+      const tab = tabs.shift();
+      BrowserTestUtils.waitForTabClosing(tab).then(resolve);
+      BrowserTestUtils.removeTab(tab);
+    });
+  }
+});
diff --git a/widget/tests/browser/browser_test_ContentCache.js b/widget/tests/browser/browser_test_ContentCache.js
new file mode 100644
index 0000000000..7b64e00f13
--- /dev/null
+++ b/widget/tests/browser/browser_test_ContentCache.js
@@ -0,0 +1,296 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function () {
+  const TIP = Cc["@mozilla.org/text-input-processor;1"].createInstance(
+    Ci.nsITextInputProcessor
+  );
+  let notifications = [];
+  const observer = (aTIP, aNotification) => {
+    switch (aNotification.type) {
+      case "request-to-commit":
+        aTIP.commitComposition();
+        break;
+      case "request-to-cancel":
+        aTIP.cancelComposition();
+        break;
+      case "notify-end-input-transaction":
+      case "notify-focus":
+      case "notify-blur":
+      case "notify-text-change":
+      case "notify-selection-change":
+        notifications.push(aNotification);
+        break;
+    }
+    return true;
+  };
+
+  function checkNotifications(aExpectedNotifications, aDescription) {
+    for (const expectedNotification of aExpectedNotifications) {
+      const notification = notifications.find(
+        element => element.type == expectedNotification.type
+      );
+      if (expectedNotification.expected) {
+        isnot(
+          notification,
+          undefined,
+          `"${expectedNotification.type}" should be notified ${aDescription}`
+        );
+      } else {
+        is(
+          notification,
+          undefined,
+          `"${expectedNotification.type}" should not be notified ${aDescription}`
+        );
+      }
+    }
+  }
+
+  ok(
+    TIP.beginInputTransaction(window, observer),
+    "nsITextInputProcessor.beingInputTransaction should return true"
+  );
+  ok(
+    TIP.beginInputTransactionForTests(window, observer),
+    "nsITextInputProcessor.beginInputTransactionForTests should return true"
+  );
+
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/browser/toolkit/content/tests/browser/file_empty.html",
+    async function (browser) {
+      ok(browser.isRemoteBrowser, "This test passes only in e10s mode");
+
+      // IMEContentObserver flushes pending IME notifications at next vsync
+      // after something happens.  Therefore, after doing something in content
+      // process, we need to guarantee that IMEContentObserver has a change to
+      // send IME notifications to the main process with calling this function.
+      function waitForSendingIMENotificationsInContent() {
+        return SpecialPowers.spawn(browser, [], async () => {
+          await new Promise(resolve =>
+            content.requestAnimationFrame(() =>
+              content.requestAnimationFrame(resolve)
+            )
+          );
+        });
+      }
+
+      /**
+       * Test when empty editor gets focus
+       */
+      notifications = [];
+      await SpecialPowers.spawn(browser, [], () => {
+        content.document.body.innerHTML = "<div contenteditable><br></div>";
+        const editor = content.document.querySelector("div[contenteditable]");
+        editor.focus();
+      });
+
+      await waitForSendingIMENotificationsInContent();
+
+      (function () {
+        checkNotifications(
+          [
+            { type: "notify-focus", expected: true },
+            { type: "notify-blur", expected: false },
+            { type: "notify-end-input-transaction", expected: false },
+            { type: "notify-text-change", expected: false },
+            { type: "notify-selection-change", expected: false },
+          ],
+          "after empty editor gets focus"
+        );
+        const text = EventUtils.synthesizeQueryTextContent(0, 1000);
+        ok(
+          text?.succeeded,
+          "query text content should succeed after empty editor gets focus"
+        );
+        if (text?.succeeded) {
+          is(
+            text.text.replace(/[\r\n]/g, ""),
+            "",
+            "text should be only line breaks after empty editor gets focus"
+          );
+        }
+        const selection = EventUtils.synthesizeQuerySelectedText();
+        ok(
+          selection?.succeeded,
+          "query selected text should succeed after empty editor gets focus"
+        );
+        if (selection?.succeeded) {
+          ok(
+            !selection.notFound,
+            "query selected text should find a selection range after empty editor gets focus"
+          );
+          if (!selection.notFound) {
+            is(
+              selection.text,
+              "",
+              "selection should be collapsed after empty editor gets focus"
+            );
+          }
+        }
+      })();
+
+      /**
+       * Test when there is non-collapsed selection
+       */
+      notifications = [];
+      await SpecialPowers.spawn(browser, [], () => {
+        const editor = content.document.querySelector("div[contenteditable]");
+        editor.innerHTML = "<p>abc</p><p>def</p>";
+        content
+          .getSelection()
+          .setBaseAndExtent(
+            editor.querySelector("p").firstChild,
+            2,
+            editor.querySelector("p + p").firstChild,
+            1
+          );
+      });
+
+      await waitForSendingIMENotificationsInContent();
+
+      (function () {
+        checkNotifications(
+          [
+            { type: "notify-focus", expected: false },
+            { type: "notify-blur", expected: false },
+            { type: "notify-end-input-transaction", expected: false },
+            { type: "notify-text-change", expected: true },
+            { type: "notify-selection-change", expected: true },
+          ],
+          "after modifying focused editor"
+        );
+        const text = EventUtils.synthesizeQueryTextContent(0, 1000);
+        ok(
+          text?.succeeded,
+          "query text content should succeed after modifying focused editor"
+        );
+        if (text?.succeeded) {
+          is(
+            text.text.trim().replace(/\r\n/g, "\n").replace(/\n\n+/g, "\n"),
+            "abc\ndef",
+            "text should include the both paragraph's text after modifying focused editor"
+          );
+        }
+        const selection = EventUtils.synthesizeQuerySelectedText();
+        ok(
+          selection?.succeeded,
+          "query selected text should succeed after modifying focused editor"
+        );
+        if (selection?.succeeded) {
+          ok(
+            !selection.notFound,
+            "query selected text should find a selection range after modifying focused editor"
+          );
+          if (!selection.notFound) {
+            is(
+              selection.text
+                .trim()
+                .replace(/\r\n/g, "\n")
+                .replace(/\n\n+/g, "\n"),
+              "c\nd",
+              "selection should have the selected characters in the both paragraphs after modifying focused editor"
+            );
+          }
+        }
+      })();
+
+      /**
+       * Test when there is no selection ranges
+       */
+      notifications = [];
+      await SpecialPowers.spawn(browser, [], () => {
+        content.getSelection().removeAllRanges();
+      });
+
+      await waitForSendingIMENotificationsInContent();
+
+      (function () {
+        checkNotifications(
+          [
+            { type: "notify-focus", expected: false },
+            { type: "notify-blur", expected: false },
+            { type: "notify-end-input-transaction", expected: false },
+            { type: "notify-text-change", expected: false },
+            { type: "notify-selection-change", expected: true },
+          ],
+          "after removing all selection ranges from the focused editor"
+        );
+        const text = EventUtils.synthesizeQueryTextContent(0, 1000);
+        ok(
+          text?.succeeded,
+          "query text content should succeed after removing all selection ranges from the focused editor"
+        );
+        if (text?.succeeded) {
+          is(
+            text.text.trim().replace(/\r\n/g, "\n").replace(/\n\n+/g, "\n"),
+            "abc\ndef",
+            "text should include the both paragraph's text after removing all selection ranges from the focused editor"
+          );
+        }
+        const selection = EventUtils.synthesizeQuerySelectedText();
+        ok(
+          selection?.succeeded,
+          "query selected text should succeed after removing all selection ranges from the focused editor"
+        );
+        if (selection?.succeeded) {
+          ok(
+            selection.notFound,
+            "query selected text should find no selection range after removing all selection ranges from the focused editor"
+          );
+        }
+      })();
+
+      /**
+       * Test when no editable element has focus.
+       */
+      notifications = [];
+      await SpecialPowers.spawn(browser, [], () => {
+        content.document.body.innerHTML = "abcdef";
+      });
+
+      await waitForSendingIMENotificationsInContent();
+
+      (function () {
+        checkNotifications(
+          [
+            { type: "notify-focus", expected: false },
+            { type: "notify-blur", expected: true },
+          ],
+          "removing editor should make ContentCacheInParent not have any data"
+        );
+        const text = EventUtils.synthesizeQueryTextContent(0, 1000);
+        ok(
+          !text?.succeeded,
+          "query text content should fail because no editable element has focus"
+        );
+        const selection = EventUtils.synthesizeQuerySelectedText();
+        ok(
+          !selection?.succeeded,
+          "query selected text should fail because no editable element has focus"
+        );
+        const caret = EventUtils.synthesizeQueryCaretRect(0);
+        ok(
+          !caret?.succeeded,
+          "query caret rect should fail because no editable element has focus"
+        );
+        const textRect = EventUtils.synthesizeQueryTextRect(0, 5, false);
+        ok(
+          !textRect?.succeeded,
+          "query text rect should fail because no editable element has focus"
+        );
+        const textRectArray = EventUtils.synthesizeQueryTextRectArray(0, 5);
+        ok(
+          !textRectArray?.succeeded,
+          "query text rect array should fail because no editable element has focus"
+        );
+        const editorRect = EventUtils.synthesizeQueryEditorRect();
+        todo(
+          !editorRect?.succeeded,
+          "query editor rect should fail because no editable element has focus"
+        );
+      })();
+    }
+  );
+});
diff --git a/widget/tests/browser/browser_test_InputContextURI.js b/widget/tests/browser/browser_test_InputContextURI.js
new file mode 100644
index 0000000000..52f05d90f9
--- /dev/null
+++ b/widget/tests/browser/browser_test_InputContextURI.js
@@ -0,0 +1,156 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const gDOMWindowUtils = EventUtils._getDOMWindowUtils(window);
+
+function promiseURLBarFocus() {
+  const waitForFocusInURLBar = BrowserTestUtils.waitForEvent(gURLBar, "focus");
+  gURLBar.blur();
+  gURLBar.focus();
+  return Promise.all([
+    waitForFocusInURLBar,
+    TestUtils.waitForCondition(
+      () =>
+        gDOMWindowUtils.IMEStatus === Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED &&
+        gDOMWindowUtils.inputContextOrigin ===
+          Ci.nsIDOMWindowUtils.INPUT_CONTEXT_ORIGIN_MAIN
+    ),
+  ]);
+}
+
+function promiseIMEStateEnabledByRemote() {
+  return TestUtils.waitForCondition(
+    () =>
+      gDOMWindowUtils.IMEStatus === Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED &&
+      gDOMWindowUtils.inputContextOrigin ===
+        Ci.nsIDOMWindowUtils.INPUT_CONTEXT_ORIGIN_CONTENT
+  );
+}
+
+async function test_url_bar_url(aDesc) {
+  await promiseURLBarFocus();
+
+  is(
+    gDOMWindowUtils.inputContextURI,
+    null,
+    `When the search bar has focus, input context URI should be null because of in chrome document (${aDesc})`
+  );
+}
+
+async function test_input_in_http_or_https(aIsHTTPS) {
+  await promiseURLBarFocus();
+
+  const scheme = aIsHTTPS ? "https" : "http";
+  const url = `${scheme}://example.com/browser/toolkit/content/tests/browser/file_empty.html`;
+  await BrowserTestUtils.withNewTab(url, async browser => {
+    ok(browser.isRemoteBrowser, "This test passes only in e10s mode");
+
+    await SpecialPowers.spawn(browser, [], async () => {
+      content.document.body.innerHTML = "<input>";
+      const input = content.document.querySelector("input");
+      input.focus();
+
+      // Wait for a tick for flushing IMEContentObserver's pending notifications.
+      await new Promise(resolve =>
+        content.requestAnimationFrame(() =>
+          content.requestAnimationFrame(resolve)
+        )
+      );
+    });
+
+    await promiseIMEStateEnabledByRemote();
+    if (!gDOMWindowUtils.inputContextURI) {
+      ok(
+        false,
+        `Input context should have valid URI when the scheme of focused tab's URL is ${scheme}`
+      );
+      return;
+    }
+    is(
+      gDOMWindowUtils.inputContextURI.spec,
+      url,
+      `Input context should have the document URI when the scheme of focused tab's URL is ${scheme}`
+    );
+  });
+}
+
+add_task(async () => {
+  await test_url_bar_url("first check");
+});
+add_task(async () => {
+  await test_input_in_http_or_https(true);
+});
+add_task(async () => {
+  await test_url_bar_url("check after remote content sets the URI");
+});
+add_task(async () => {
+  await test_input_in_http_or_https(false);
+});
+
+add_task(async function test_input_in_data() {
+  await BrowserTestUtils.withNewTab("data:text/html,<input>", async browser => {
+    ok(browser.isRemoteBrowser, "This test passes only in e10s mode");
+
+    await SpecialPowers.spawn(browser, [], async () => {
+      const input = content.document.querySelector("input");
+      input.focus();
+
+      // Wait for a tick for flushing IMEContentObserver's pending notifications.
+      await new Promise(resolve =>
+        content.requestAnimationFrame(() =>
+          content.requestAnimationFrame(resolve)
+        )
+      );
+    });
+
+    await promiseIMEStateEnabledByRemote();
+    is(
+      gDOMWindowUtils.inputContextURI,
+      null,
+      "Input context should not have data URI"
+    );
+  });
+});
+
+add_task(async function test_omit_private_things_in_URL() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["network.auth.confirmAuth.enabled", false]],
+  });
+  await promiseURLBarFocus();
+
+  await BrowserTestUtils.withNewTab(
+    "https://username:password@example.com/browser/toolkit/content/tests/browser/file_empty.html?query=some#ref",
+    async browser => {
+      ok(browser.isRemoteBrowser, "This test passes only in e10s mode");
+
+      await SpecialPowers.spawn(browser, [], async () => {
+        content.document.body.innerHTML = "<input>";
+        const input = content.document.querySelector("input");
+        input.focus();
+
+        // Wait for a tick for flushing IMEContentObserver's pending notifications.
+        await new Promise(resolve =>
+          content.requestAnimationFrame(() =>
+            content.requestAnimationFrame(resolve)
+          )
+        );
+      });
+
+      await promiseIMEStateEnabledByRemote();
+      if (!gDOMWindowUtils.inputContextURI) {
+        ok(
+          false,
+          `Input context should have valid URI even when the URL contains some private things`
+        );
+        return;
+      }
+      is(
+        gDOMWindowUtils.inputContextURI.spec,
+        "https://example.com/browser/toolkit/content/tests/browser/file_empty.html",
+        `Input context should have the document URI which omit some private things in the URL`
+      );
+    }
+  );
+});
diff --git a/widget/tests/browser/browser_test_clipboard_contextmenu.js b/widget/tests/browser/browser_test_clipboard_contextmenu.js
new file mode 100644
index 0000000000..4d268d5be4
--- /dev/null
+++ b/widget/tests/browser/browser_test_clipboard_contextmenu.js
@@ -0,0 +1,127 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+"use strict";
+
+const clipboard = SpecialPowers.Services.clipboard;
+const clipboardTypes = [
+  clipboard.kGlobalClipboard,
+  clipboard.kSelectionClipboard,
+  clipboard.kFindClipboard,
+  clipboard.kSelectionCache,
+];
+const supportedClipboardTypes = clipboardTypes.filter(type =>
+  clipboard.isClipboardTypeSupported(type)
+);
+
+const kPasteMenuPopupId = "clipboardReadPasteMenuPopup";
+const kPasteMenuItemId = "clipboardReadPasteMenuItem";
+
+function waitForPasteMenuPopupEvent(aEventSuffix) {
+  // The element with id `kPasteMenuPopupId` is inserted dynamically, hence
+  // calling `BrowserTestUtils.waitForEvent` instead of
+  // `BrowserTestUtils.waitForPopupEvent`.
+  return BrowserTestUtils.waitForEvent(
+    document,
+    "popup" + aEventSuffix,
+    false /* capture */,
+    e => {
+      return e.target.getAttribute("id") == kPasteMenuPopupId;
+    }
+  );
+}
+
+async function waitForPasteContextMenu() {
+  await waitForPasteMenuPopupEvent("shown");
+  const pasteButton = document.getElementById(kPasteMenuItemId);
+  info("Wait for paste button enabled");
+  await BrowserTestUtils.waitForMutationCondition(
+    pasteButton,
+    { attributeFilter: ["disabled"] },
+    () => !pasteButton.disabled,
+    "Wait for paste button enabled"
+  );
+}
+
+function promiseClickPasteButton() {
+  info("Wait for clicking paste contextmenu");
+  const pasteButton = document.getElementById(kPasteMenuItemId);
+  let promise = BrowserTestUtils.waitForEvent(pasteButton, "click");
+  EventUtils.synthesizeMouseAtCenter(pasteButton, {});
+  return promise;
+}
+
+async function clipboardAsyncGetData(aBrowser, aClipboardType) {
+  await SpecialPowers.spawn(aBrowser, [aClipboardType], async type => {
+    return new Promise((resolve, reject) => {
+      SpecialPowers.Services.clipboard.asyncGetData(
+        ["text/plain"],
+        type,
+        content.browsingContext.currentWindowContext,
+        content.document.nodePrincipal,
+        {
+          QueryInterface: SpecialPowers.ChromeUtils.generateQI([
+            "nsIAsyncClipboardGetCallback",
+          ]),
+          // nsIAsyncClipboardGetCallback
+          onSuccess: aAsyncGetClipboardData => {
+            resolve();
+          },
+          onError: aResult => {
+            reject(aResult);
+          },
+        }
+      );
+    });
+  });
+}
+
+add_setup(async function () {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      // Avoid paste button delay enabling making test too long.
+      ["security.dialog_enable_delay", 0],
+    ],
+  });
+});
+
+supportedClipboardTypes.forEach(type => {
+  add_task(async function test_clipboard_contextmenu() {
+    await BrowserTestUtils.withNewTab(
+      "https://example.com",
+      async function (browser) {
+        info(`Test clipboard contextmenu for clipboard type ${type}`);
+        let pasteContextMenuPromise = waitForPasteContextMenu();
+        const asyncRead = clipboardAsyncGetData(browser, type);
+        await pasteContextMenuPromise;
+
+        // We don't allow requests for different clipboard type to be
+        // consolidated, so when the context menu is shown for a specific
+        // clipboard type and has not yet got user response, any new requests
+        // for a different type should be rejected.
+        info(
+          "Test other clipboard types before interact with paste contextmenu"
+        );
+        for (let otherType of supportedClipboardTypes) {
+          if (type == otherType) {
+            continue;
+          }
+
+          info(`Test other clipboard type ${otherType}`);
+          await Assert.rejects(
+            clipboardAsyncGetData(browser, otherType),
+            ex => ex == Cr.NS_ERROR_DOM_NOT_ALLOWED_ERR,
+            `Request for clipboard type ${otherType} should be rejected`
+          );
+        }
+
+        await promiseClickPasteButton();
+        try {
+          await asyncRead;
+          ok(true, `nsIClipboard.asyncGetData() should success`);
+        } catch (e) {
+          ok(false, `nsIClipboard.asyncGetData() should not fail with ${e}`);
+        }
+      }
+    );
+  });
+});
diff --git a/widget/tests/browser/browser_test_clipboardcache.js b/widget/tests/browser/browser_test_clipboardcache.js
new file mode 100644
index 0000000000..8cb6adb8b5
--- /dev/null
+++ b/widget/tests/browser/browser_test_clipboardcache.js
@@ -0,0 +1,137 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+"use strict";
+
+// Note: widget/tests/test_bug1123480.xhtml checks whether nsTransferable behaves
+// as expected with regards to private browsing mode and the clipboard cache,
+// i.e. that the clipboard is not cached to the disk when private browsing mode
+// is enabled.
+//
+// This test tests that the clipboard is not cached to the disk by IPC,
+// as a regression test for bug 1396224.
+// It indirectly uses nsTransferable, via the async navigator.clipboard API.
+
+// Create over 1 MB of sample garbage text. JavaScript strings are represented
+// by UTF16 strings, so the size is twice as much as the actual string length.
+// This value is chosen such that the size of the memory for the string exceeds
+// the kLargeDatasetSize threshold in nsTransferable.h.
+// It is also not a round number to reduce the odds of having an accidental
+// collisions with another file (since the test below looks at the file size
+// to identify the file).
+var Ipsum = "0123456789".repeat(1234321);
+var IpsumByteLength = Ipsum.length * 2;
+var SHORT_STRING_NO_CACHE = "short string that will not be cached to the disk";
+
+// Get a list of open file descriptors that refer to a file with the same size
+// as the expected data (and assume that any mutations in file descriptor counts
+// are caused by our test).
+// TODO: This logic only counts file descriptors that are still open (e.g. when
+// data persists after a copy). It does not detect cache files that exist only
+// temporarily (e.g. after a paste).
+function getClipboardCacheFDCount() {
+  let dir = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
+  if (AppConstants.platform === "win") {
+    // On Windows, nsAnonymousTemporaryFile does not immediately delete a file.
+    // Instead, the Windows-specific FILE_FLAG_DELETE_ON_CLOSE flag is used,
+    // which means that the file is deleted when the last handle is closed.
+    // Apparently, this flag is unreliable (e.g. when the application crashes),
+    // so nsAnonymousTemporaryFile stores the temporary files in a subdirectory,
+    // which is cleaned up some time after start-up.
+
+    // This is just a test, and during the test we deterministically close the
+    // handles, so if FILE_FLAG_DELETE_ON_CLOSE does the thing it promises, the
+    // file is actually removed when the handle is closed.
+
+    // Path from nsAnonymousTemporaryFile.cpp, GetTempDir.
+    dir.initWithPath(PathUtils.join(PathUtils.tempDir, "mozilla-temp-files"));
+  } else {
+    dir.initWithPath("/dev/fd");
+  }
+  let count = 0;
+  for (let fdFile of dir.directoryEntries) {
+    let fileSize;
+    try {
+      fileSize = fdFile.fileSize;
+    } catch (e) {
+      // This can happen on macOS.
+      continue;
+    }
+    if (fileSize === IpsumByteLength) {
+      // Assume that the file was created by us if the size matches.
+      ++count;
+    }
+  }
+  return count;
+}
+
+async function testCopyPaste(isPrivate) {
+  let win = await BrowserTestUtils.openNewBrowserWindow({ private: isPrivate });
+  let tab = await BrowserTestUtils.openNewForegroundTab(win);
+  let browser = tab.linkedBrowser;
+
+  // Sanitize environment
+  await ContentTask.spawn(browser, SHORT_STRING_NO_CACHE, async shortStr => {
+    await content.navigator.clipboard.writeText(shortStr);
+  });
+
+  let initialFdCount = getClipboardCacheFDCount();
+
+  await SpecialPowers.spawn(browser, [Ipsum], async largeString => {
+    await content.navigator.clipboard.writeText(largeString);
+  });
+
+  let fdCountAfterCopy = getClipboardCacheFDCount();
+  if (isPrivate) {
+    is(fdCountAfterCopy, initialFdCount, "Private write");
+  } else {
+    is(fdCountAfterCopy, initialFdCount + 1, "Cached write");
+  }
+
+  let readStr = await SpecialPowers.spawn(browser, [], async () => {
+    let { document } = content;
+    document.body.contentEditable = true;
+    document.body.focus();
+    let pastePromise = new Promise(resolve => {
+      document.addEventListener(
+        "paste",
+        e => {
+          resolve(e.clipboardData.getData("text/plain"));
+        },
+        { once: true }
+      );
+    });
+    document.execCommand("paste");
+    return pastePromise;
+  });
+  ok(readStr === Ipsum, "Read what we pasted");
+
+  if (isPrivate) {
+    is(getClipboardCacheFDCount(), fdCountAfterCopy, "Private read");
+  } else {
+    // Upon reading from the clipboard, a temporary nsTransferable is used, for
+    // which the cache is disabled. The content process does not cache clipboard
+    // data either. So the file descriptor count should be identical.
+    is(getClipboardCacheFDCount(), fdCountAfterCopy, "Read not cached");
+  }
+
+  // Cleanup.
+  await SpecialPowers.spawn(
+    browser,
+    [SHORT_STRING_NO_CACHE],
+    async shortStr => {
+      await content.navigator.clipboard.writeText(shortStr);
+    }
+  );
+  is(getClipboardCacheFDCount(), initialFdCount, "Drop clipboard cache if any");
+
+  BrowserTestUtils.removeTab(tab);
+  await BrowserTestUtils.closeWindow(win);
+}
+
+add_task(async function test_private() {
+  await testCopyPaste(true);
+});
+
+add_task(async function test_non_private() {
+  await testCopyPaste(false);
+});
diff --git a/widget/tests/browser/browser_test_fullscreen_size.js b/widget/tests/browser/browser_test_fullscreen_size.js
new file mode 100644
index 0000000000..dace46603c
--- /dev/null
+++ b/widget/tests/browser/browser_test_fullscreen_size.js
@@ -0,0 +1,66 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+"use strict";
+
+function waitForReflow(aWindow) {
+  return new Promise(resolve => {
+    aWindow.requestAnimationFrame(() => {
+      aWindow.requestAnimationFrame(resolve);
+    });
+  });
+}
+
+add_task(async function fullscreen_size() {
+  let win = await BrowserTestUtils.openNewBrowserWindow({});
+  win.gBrowser.selectedBrowser.focus();
+
+  info("Enter browser fullscreen mode");
+  let promise = Promise.all([
+    BrowserTestUtils.waitForEvent(win, "fullscreen"),
+    BrowserTestUtils.waitForEvent(win, "resize"),
+  ]);
+  win.fullScreen = true;
+  await promise;
+
+  info("Await reflow of the chrome window");
+  await waitForReflow(win);
+
+  is(win.innerHeight, win.outerHeight, "Check height");
+  is(win.innerWidth, win.outerWidth, "Check width");
+
+  await BrowserTestUtils.closeWindow(win);
+});
+
+// https://bugzilla.mozilla.org/show_bug.cgi?id=1830721
+add_task(async function fullscreen_size_moz_appearance() {
+  const win = await BrowserTestUtils.openNewBrowserWindow({});
+  win.gBrowser.selectedBrowser.focus();
+
+  info("Add -moz-appearance style to chrome document");
+  const style = win.document.createElement("style");
+  style.innerHTML = `
+    #main-window {
+      -moz-appearance: button;
+    }
+  `;
+  win.document.head.appendChild(style);
+
+  info("Await reflow of the chrome window");
+  await waitForReflow(win);
+
+  info("Enter browser fullscreen mode");
+  let promise = Promise.all([
+    BrowserTestUtils.waitForEvent(win, "fullscreen"),
+    BrowserTestUtils.waitForEvent(win, "resize"),
+  ]);
+  win.fullScreen = true;
+  await promise;
+
+  info("Await reflow of the chrome window");
+  await waitForReflow(win);
+
+  is(win.innerHeight, win.outerHeight, "Check height");
+  is(win.innerWidth, win.outerWidth, `Check width`);
+
+  await BrowserTestUtils.closeWindow(win);
+});
diff --git a/widget/tests/browser/browser_test_ime_state_in_contenteditable_on_focus_move_in_remote_content.js b/widget/tests/browser/browser_test_ime_state_in_contenteditable_on_focus_move_in_remote_content.js
new file mode 100644
index 0000000000..50b19f0cc3
--- /dev/null
+++ b/widget/tests/browser/browser_test_ime_state_in_contenteditable_on_focus_move_in_remote_content.js
@@ -0,0 +1,122 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from ../file_ime_state_test_helper.js */
+/* import-globals-from ../file_test_ime_state_on_focus_move.js */
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_ime_state_test_helper.js",
+  this
+);
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_test_ime_state_on_focus_move.js",
+  this
+);
+add_task(async function () {
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/browser/widget/tests/browser/file_ime_state_tests.html",
+    async function (browser) {
+      const tipWrapper = new TIPWrapper(window);
+      ok(
+        tipWrapper.isAvailable(),
+        "TextInputProcessor should've been initialized"
+      );
+
+      // isnot is used in file_test_ime_state_on_focus_move.js, but it's not
+      // defined as the alias of Assert.notEqual in browser-chrome tests.
+      // Therefore, we need to define it here.
+      // eslint-disable-next-line no-unused-vars
+      const isnot = Assert.notEqual;
+
+      async function runIMEStateOnFocusMoveTests(aDescription) {
+        await (async function test_IMEState_without_focused_element() {
+          const checker = new IMEStateWhenNoActiveElementTester(aDescription);
+          const expectedData = await SpecialPowers.spawn(
+            browser,
+            [aDescription],
+            description => {
+              const runner =
+                content.wrappedJSObject.createIMEStateWhenNoActiveElementTester(
+                  description
+                );
+              return runner.run(content.document, content.window);
+            }
+          );
+          checker.check(expectedData);
+        })();
+        for (
+          let index = 0;
+          index < IMEStateOnFocusMoveTester.numberOfTests;
+          ++index
+        ) {
+          const checker = new IMEStateOnFocusMoveTester(aDescription, index);
+          const expectedData = await SpecialPowers.spawn(
+            browser,
+            [aDescription, index],
+            (description, aIndex) => {
+              content.wrappedJSObject.runner =
+                content.wrappedJSObject.createIMEStateOnFocusMoveTester(
+                  description,
+                  aIndex,
+                  content.window
+                );
+              return content.wrappedJSObject.runner.prepareToRun(
+                content.document.querySelector("div")
+              );
+            }
+          );
+          checker.prepareToCheck(expectedData, tipWrapper);
+          await SpecialPowers.spawn(browser, [], () => {
+            return content.wrappedJSObject.runner.run();
+          });
+          checker.check(expectedData);
+
+          if (checker.canTestOpenCloseState(expectedData)) {
+            for (const defaultOpenState of [false, true]) {
+              const expectedOpenStateData = await SpecialPowers.spawn(
+                browser,
+                [],
+                () => {
+                  return content.wrappedJSObject.runner.prepareToRunOpenCloseTest(
+                    content.document.querySelector("div")
+                  );
+                }
+              );
+              checker.prepareToCheckOpenCloseTest(
+                defaultOpenState,
+                expectedOpenStateData
+              );
+              await SpecialPowers.spawn(browser, [], () => {
+                return content.wrappedJSObject.runner.runOpenCloseTest();
+              });
+              checker.checkOpenCloseTest(expectedOpenStateData);
+            }
+          }
+          await SpecialPowers.spawn(browser, [], () => {
+            content.wrappedJSObject.runner.destroy();
+            content.wrappedJSObject.runner = undefined;
+          });
+          checker.destroy();
+        } // for loop iterating test of IMEStateOnFocusMoveTester
+      } // definition of runIMEStateOnFocusMoveTests
+
+      // test for contentEditable="true"
+      await SpecialPowers.spawn(browser, [], async () => {
+        content.document
+          .querySelector("div")
+          .setAttribute("contenteditable", "true");
+      });
+      await runIMEStateOnFocusMoveTests("in div[contenteditable]");
+
+      // test for contentEditable="false"
+      await SpecialPowers.spawn(browser, [], async () => {
+        content.document
+          .querySelector("div")
+          .setAttribute("contenteditable", "false");
+      });
+      await runIMEStateOnFocusMoveTests('in div[contenteditable="false"]');
+    }
+  );
+});
diff --git a/widget/tests/browser/browser_test_ime_state_in_contenteditable_on_readonly_change_in_remote_content.js b/widget/tests/browser/browser_test_ime_state_in_contenteditable_on_readonly_change_in_remote_content.js
new file mode 100644
index 0000000000..33217d1d2c
--- /dev/null
+++ b/widget/tests/browser/browser_test_ime_state_in_contenteditable_on_readonly_change_in_remote_content.js
@@ -0,0 +1,261 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from ../file_ime_state_test_helper.js */
+/* import-globals-from ../file_test_ime_state_in_contenteditable_on_readonly_change.js */
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_ime_state_test_helper.js",
+  this
+);
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_test_ime_state_in_contenteditable_on_readonly_change.js",
+  this
+);
+add_task(async function () {
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/browser/widget/tests/browser/file_ime_state_tests.html",
+    async function (browser) {
+      const tipWrapper = new TIPWrapper(window);
+      ok(
+        tipWrapper.isAvailable(),
+        "TextInputProcessor should've been initialized"
+      );
+
+      await (async function test_ime_state_in_contenteditable_on_readonly_change() {
+        const expectedDataOfInitialization = await SpecialPowers.spawn(
+          browser,
+          [],
+          () => {
+            content.document.body.innerHTML = "<div contenteditable><br></div>";
+            content.wrappedJSObject.runner =
+              content.wrappedJSObject.createIMEStateInContentEditableOnReadonlyChangeTester();
+            const editingHost = content.document.querySelector(
+              "div[contenteditable]"
+            );
+            return content.wrappedJSObject.runner.prepareToRun(
+              editingHost,
+              editingHost,
+              content.window
+            );
+          }
+        );
+        const tester = new IMEStateInContentEditableOnReadonlyChangeTester();
+        tester.checkResultOfPreparation(
+          expectedDataOfInitialization,
+          window,
+          tipWrapper
+        );
+        const expectedDataOfReadonly = await SpecialPowers.spawn(
+          browser,
+          [],
+          () => {
+            return content.wrappedJSObject.runner.runToMakeHTMLEditorReadonly();
+          }
+        );
+        tester.checkResultOfMakingHTMLEditorReadonly(expectedDataOfReadonly);
+        const expectedDataOfEditable = await SpecialPowers.spawn(
+          browser,
+          [],
+          () => {
+            return content.wrappedJSObject.runner.runToMakeHTMLEditorEditable();
+          }
+        );
+        tester.checkResultOfMakingHTMLEditorEditable(expectedDataOfEditable);
+        const expectedDataOfFinalization = await SpecialPowers.spawn(
+          browser,
+          [],
+          () => {
+            return content.wrappedJSObject.runner.runToRemoveContentEditableAttribute();
+          }
+        );
+        tester.checkResultOfRemovingContentEditableAttribute(
+          expectedDataOfFinalization
+        );
+        tester.clear();
+      })();
+
+      await (async function test_ime_state_in_button_in_contenteditable_on_readonly_change() {
+        const expectedDataOfInitialization = await SpecialPowers.spawn(
+          browser,
+          [],
+          () => {
+            content.document.body.innerHTML =
+              "<div contenteditable><br><button>button</button></div>";
+            content.wrappedJSObject.runner =
+              content.wrappedJSObject.createIMEStateInContentEditableOnReadonlyChangeTester();
+            const editingHost = content.document.querySelector(
+              "div[contenteditable]"
+            );
+            return content.wrappedJSObject.runner.prepareToRun(
+              editingHost,
+              editingHost.querySelector("button"),
+              content.window
+            );
+          }
+        );
+        const tester = new IMEStateInContentEditableOnReadonlyChangeTester();
+        tester.checkResultOfPreparation(
+          expectedDataOfInitialization,
+          window,
+          tipWrapper
+        );
+        const expectedDataOfReadonly = await SpecialPowers.spawn(
+          browser,
+          [],
+          () => {
+            return content.wrappedJSObject.runner.runToMakeHTMLEditorReadonly();
+          }
+        );
+        tester.checkResultOfMakingHTMLEditorReadonly(expectedDataOfReadonly);
+        const expectedDataOfEditable = await SpecialPowers.spawn(
+          browser,
+          [],
+          () => {
+            return content.wrappedJSObject.runner.runToMakeHTMLEditorEditable();
+          }
+        );
+        tester.checkResultOfMakingHTMLEditorEditable(expectedDataOfEditable);
+        const expectedDataOfFinalization = await SpecialPowers.spawn(
+          browser,
+          [],
+          () => {
+            return content.wrappedJSObject.runner.runToRemoveContentEditableAttribute();
+          }
+        );
+        tester.checkResultOfRemovingContentEditableAttribute(
+          expectedDataOfFinalization
+        );
+        tester.clear();
+      })();
+
+      await (async function test_ime_state_of_text_controls_in_contenteditable_on_readonly_change() {
+        const tester =
+          new IMEStateOfTextControlInContentEditableOnReadonlyChangeTester();
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document.body.innerHTML = "<div contenteditable></div>";
+          content.wrappedJSObject.runner =
+            content.wrappedJSObject.createIMEStateOfTextControlInContentEditableOnReadonlyChangeTester();
+        });
+        for (
+          let index = 0;
+          index <
+          IMEStateOfTextControlInContentEditableOnReadonlyChangeTester.numberOfTextControlTypes;
+          index++
+        ) {
+          const expectedDataOfInitialization = await SpecialPowers.spawn(
+            browser,
+            [index],
+            aIndex => {
+              const editingHost = content.document.querySelector("div");
+              return content.wrappedJSObject.runner.prepareToRun(
+                aIndex,
+                editingHost,
+                content.window
+              );
+            }
+          );
+          tester.checkResultOfPreparation(
+            expectedDataOfInitialization,
+            window,
+            tipWrapper
+          );
+          const expectedDataOfMakingParentEditingHost =
+            await SpecialPowers.spawn(browser, [], () => {
+              return content.wrappedJSObject.runner.runToMakeParentEditingHost();
+            });
+          tester.checkResultOfMakingParentEditingHost(
+            expectedDataOfMakingParentEditingHost
+          );
+          const expectedDataOfMakingHTMLEditorReadonly =
+            await SpecialPowers.spawn(browser, [], () => {
+              return content.wrappedJSObject.runner.runToMakeHTMLEditorReadonly();
+            });
+          tester.checkResultOfMakingHTMLEditorReadonly(
+            expectedDataOfMakingHTMLEditorReadonly
+          );
+          const expectedDataOfMakingHTMLEditorEditable =
+            await SpecialPowers.spawn(browser, [], () => {
+              return content.wrappedJSObject.runner.runToMakeHTMLEditorEditable();
+            });
+          tester.checkResultOfMakingHTMLEditorEditable(
+            expectedDataOfMakingHTMLEditorEditable
+          );
+          const expectedDataOfMakingParentNonEditable =
+            await SpecialPowers.spawn(browser, [], () => {
+              return content.wrappedJSObject.runner.runToMakeParentNonEditingHost();
+            });
+          tester.checkResultOfMakingParentNonEditable(
+            expectedDataOfMakingParentNonEditable
+          );
+          tester.clear();
+        }
+      })();
+
+      await (async function test_ime_state_outside_contenteditable_on_readonly_change() {
+        const tester =
+          new IMEStateOutsideContentEditableOnReadonlyChangeTester();
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document.body.innerHTML = "<div contenteditable></div>";
+          content.wrappedJSObject.runner =
+            content.wrappedJSObject.createIMEStateOutsideContentEditableOnReadonlyChangeTester();
+        });
+        for (
+          let index = 0;
+          index <
+          IMEStateOutsideContentEditableOnReadonlyChangeTester.numberOfFocusTargets;
+          index++
+        ) {
+          const expectedDataOfInitialization = await SpecialPowers.spawn(
+            browser,
+            [index],
+            aIndex => {
+              const editingHost = content.document.querySelector("div");
+              return content.wrappedJSObject.runner.prepareToRun(
+                aIndex,
+                editingHost,
+                content.window
+              );
+            }
+          );
+          tester.checkResultOfPreparation(
+            expectedDataOfInitialization,
+            window,
+            tipWrapper
+          );
+          const expectedDataOfMakingParentEditingHost =
+            await SpecialPowers.spawn(browser, [], () => {
+              return content.wrappedJSObject.runner.runToMakeParentEditingHost();
+            });
+          tester.checkResultOfMakingParentEditingHost(
+            expectedDataOfMakingParentEditingHost
+          );
+          const expectedDataOfMakingHTMLEditorReadonly =
+            await SpecialPowers.spawn(browser, [], () => {
+              return content.wrappedJSObject.runner.runToMakeHTMLEditorReadonly();
+            });
+          tester.checkResultOfMakingHTMLEditorReadonly(
+            expectedDataOfMakingHTMLEditorReadonly
+          );
+          const expectedDataOfMakingHTMLEditorEditable =
+            await SpecialPowers.spawn(browser, [], () => {
+              return content.wrappedJSObject.runner.runToMakeHTMLEditorEditable();
+            });
+          tester.checkResultOfMakingHTMLEditorEditable(
+            expectedDataOfMakingHTMLEditorEditable
+          );
+          const expectedDataOfMakingParentNonEditable =
+            await SpecialPowers.spawn(browser, [], () => {
+              return content.wrappedJSObject.runner.runToMakeParentNonEditingHost();
+            });
+          tester.checkResultOfMakingParentNonEditable(
+            expectedDataOfMakingParentNonEditable
+          );
+          tester.clear();
+        }
+      })();
+    }
+  );
+});
diff --git a/widget/tests/browser/browser_test_ime_state_in_designMode_on_focus_move_in_remote_content.js b/widget/tests/browser/browser_test_ime_state_in_designMode_on_focus_move_in_remote_content.js
new file mode 100644
index 0000000000..5ea5990e96
--- /dev/null
+++ b/widget/tests/browser/browser_test_ime_state_in_designMode_on_focus_move_in_remote_content.js
@@ -0,0 +1,116 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from ../file_ime_state_test_helper.js */
+/* import-globals-from ../file_test_ime_state_on_focus_move.js */
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_ime_state_test_helper.js",
+  this
+);
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_test_ime_state_on_focus_move.js",
+  this
+);
+add_task(async function () {
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/browser/widget/tests/browser/file_ime_state_tests.html",
+    async function (browser) {
+      const tipWrapper = new TIPWrapper(window);
+      ok(
+        tipWrapper.isAvailable(),
+        "TextInputProcessor should've been initialized"
+      );
+
+      // isnot is used in file_test_ime_state_on_focus_move.js, but it's not
+      // defined as the alias of Assert.notEqual in browser-chrome tests.
+      // Therefore, we need to define it here.
+      // eslint-disable-next-line no-unused-vars
+      const isnot = Assert.notEqual;
+
+      async function runIMEStateOnFocusMoveTests(aDescription) {
+        await (async function test_IMEState_without_focused_element() {
+          const checker = new IMEStateWhenNoActiveElementTester(aDescription);
+          const expectedData = await SpecialPowers.spawn(
+            browser,
+            [aDescription],
+            description => {
+              const runner =
+                content.wrappedJSObject.createIMEStateWhenNoActiveElementTester(
+                  description
+                );
+              return runner.run(content.document, content.window);
+            }
+          );
+          checker.check(expectedData);
+        })();
+        for (
+          let index = 0;
+          index < IMEStateOnFocusMoveTester.numberOfTests;
+          ++index
+        ) {
+          const checker = new IMEStateOnFocusMoveTester(aDescription, index);
+          const expectedData = await SpecialPowers.spawn(
+            browser,
+            [aDescription, index],
+            (description, aIndex) => {
+              content.wrappedJSObject.runner =
+                content.wrappedJSObject.createIMEStateOnFocusMoveTester(
+                  description,
+                  aIndex,
+                  content.window
+                );
+              return content.wrappedJSObject.runner.prepareToRun(
+                content.document.querySelector("div")
+              );
+            }
+          );
+          checker.prepareToCheck(expectedData, tipWrapper);
+          await SpecialPowers.spawn(browser, [], () => {
+            return content.wrappedJSObject.runner.run();
+          });
+          checker.check(expectedData);
+
+          if (checker.canTestOpenCloseState(expectedData)) {
+            for (const defaultOpenState of [false, true]) {
+              const expectedOpenStateData = await SpecialPowers.spawn(
+                browser,
+                [],
+                () => {
+                  return content.wrappedJSObject.runner.prepareToRunOpenCloseTest(
+                    content.document.querySelector("div")
+                  );
+                }
+              );
+              checker.prepareToCheckOpenCloseTest(
+                defaultOpenState,
+                expectedOpenStateData
+              );
+              await SpecialPowers.spawn(browser, [], () => {
+                return content.wrappedJSObject.runner.runOpenCloseTest();
+              });
+              checker.checkOpenCloseTest(expectedOpenStateData);
+            }
+          }
+          await SpecialPowers.spawn(browser, [], () => {
+            content.wrappedJSObject.runner.destroy();
+            content.wrappedJSObject.runner = undefined;
+          });
+          checker.destroy();
+        } // for loop iterating test of IMEStateOnFocusMoveTester
+      } // definition of runIMEStateOnFocusMoveTests
+
+      // test designMode
+      await SpecialPowers.spawn(browser, [], async () => {
+        content.document.designMode = "on";
+      });
+      await runIMEStateOnFocusMoveTests('in designMode="on"');
+      await SpecialPowers.spawn(browser, [], async () => {
+        content.document.designMode = "off";
+      });
+      await runIMEStateOnFocusMoveTests('in designMode="off"');
+    }
+  );
+});
diff --git a/widget/tests/browser/browser_test_ime_state_in_plugin_in_remote_content.js b/widget/tests/browser/browser_test_ime_state_in_plugin_in_remote_content.js
new file mode 100644
index 0000000000..0862b51080
--- /dev/null
+++ b/widget/tests/browser/browser_test_ime_state_in_plugin_in_remote_content.js
@@ -0,0 +1,120 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from ../file_ime_state_test_helper.js */
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_ime_state_test_helper.js",
+  this
+);
+add_task(async function () {
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/browser/toolkit/content/tests/browser/file_empty.html",
+    async function (browser) {
+      const tipWrapper = new TIPWrapper(window);
+      ok(
+        tipWrapper.isAvailable(),
+        "TextInputProcessor should've been initialized"
+      );
+
+      await SpecialPowers.spawn(browser, [], () => {
+        content.wrappedJSObject.waitForIMEContentObserverSendingNotifications =
+          () => {
+            return new content.window.Promise(resolve =>
+              content.window.requestAnimationFrame(() =>
+                content.window.requestAnimationFrame(resolve)
+              )
+            );
+          };
+        content.document.body.innerHTML =
+          '<input><object type="application/x-test"></object>';
+      });
+
+      await SpecialPowers.spawn(browser, [], () => {
+        content.document.activeElement?.blur();
+        return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+      });
+      is(
+        window.windowUtils.IMEStatus,
+        Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+        "IME enabled state should be disabled when no element has focus"
+      );
+      ok(
+        !tipWrapper.IMEHasFocus,
+        "IME should not have focus when no element has focus"
+      );
+
+      await SpecialPowers.spawn(browser, [], () => {
+        content.document.querySelector("object").focus();
+        return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+      });
+      is(
+        window.windowUtils.IMEStatus,
+        Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+        "IME enabled state should be disabled when an <object> for plugin has focus"
+      );
+      ok(
+        !tipWrapper.IMEHasFocus,
+        "IME enabled state should not have focus when an <object> for plugin has focus"
+      );
+
+      await SpecialPowers.spawn(browser, [], () => {
+        content.document.querySelector("object").blur();
+        return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+      });
+      is(
+        window.windowUtils.IMEStatus,
+        Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+        "IME enabled state should be disabled when an <object> for plugin gets blurred"
+      );
+      ok(
+        !tipWrapper.IMEHasFocus,
+        "IME should not have focus when an <object> for plugin gets blurred"
+      );
+
+      await SpecialPowers.spawn(browser, [], () => {
+        content.document.querySelector("object").focus();
+        return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+      });
+      is(
+        window.windowUtils.IMEStatus,
+        Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+        "IME enabled state should be disabled when an <object> for plugin gets focused again"
+      );
+      ok(
+        !tipWrapper.IMEHasFocus,
+        "IME should not have focus when an <object> for plugin gets focused again"
+      );
+
+      await SpecialPowers.spawn(browser, [], () => {
+        content.document.querySelector("object").remove();
+        return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+      });
+      is(
+        window.windowUtils.IMEStatus,
+        Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+        "IME enabled state should be disabled when focused <object> for plugin is removed from the document"
+      );
+      ok(
+        !tipWrapper.IMEHasFocus,
+        "IME should not have focus when focused <object> for plugin is removed from the document"
+      );
+
+      await SpecialPowers.spawn(browser, [], () => {
+        content.document.querySelector("input").focus();
+        return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+      });
+      is(
+        window.windowUtils.IMEStatus,
+        Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+        "IME enabled state should be enabled after <input> gets focus"
+      );
+      ok(
+        tipWrapper.IMEHasFocus,
+        "IME should have focus after <input> gets focus"
+      );
+    }
+  );
+});
diff --git a/widget/tests/browser/browser_test_ime_state_in_text_control_on_reframe_in_remote_content.js b/widget/tests/browser/browser_test_ime_state_in_text_control_on_reframe_in_remote_content.js
new file mode 100644
index 0000000000..4d8acab1ff
--- /dev/null
+++ b/widget/tests/browser/browser_test_ime_state_in_text_control_on_reframe_in_remote_content.js
@@ -0,0 +1,78 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from ../file_ime_state_test_helper.js */
+/* import-globals-from ../file_test_ime_state_in_text_control_on_reframe.js */
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_ime_state_test_helper.js",
+  this
+);
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_test_ime_state_in_text_control_on_reframe.js",
+  this
+);
+add_task(async function () {
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/browser/widget/tests/browser/file_ime_state_tests.html",
+    async function (browser) {
+      const tipWrapper = new TIPWrapper(window);
+      ok(
+        tipWrapper.isAvailable(),
+        "TextInputProcessor should've been initialized"
+      );
+
+      await (async function test_ime_state_outside_contenteditable_on_readonly_change() {
+        const tester = new IMEStateInTextControlOnReframeTester();
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document.body.innerHTML = "<div contenteditable></div>";
+          content.wrappedJSObject.runner =
+            content.wrappedJSObject.createIMEStateInTextControlOnReframeTester();
+        });
+        for (
+          let index = 0;
+          index < IMEStateInTextControlOnReframeTester.numberOfTextControlTypes;
+          index++
+        ) {
+          tipWrapper.clearFocusBlurNotifications();
+          const expectedData1 = await SpecialPowers.spawn(
+            browser,
+            [index],
+            aIndex => {
+              return content.wrappedJSObject.runner.prepareToRun(
+                aIndex,
+                content.document,
+                content.window
+              );
+            }
+          );
+          tipWrapper.typeA();
+          await SpecialPowers.spawn(browser, [], () => {
+            return new Promise(resolve =>
+              content.window.requestAnimationFrame(() =>
+                content.window.requestAnimationFrame(resolve)
+              )
+            );
+          });
+          tester.checkResultAfterTypingA(expectedData1, window, tipWrapper);
+
+          const expectedData2 = await SpecialPowers.spawn(browser, [], () => {
+            return content.wrappedJSObject.runner.prepareToRun2();
+          });
+          tipWrapper.typeA();
+          await SpecialPowers.spawn(browser, [], () => {
+            return new Promise(resolve =>
+              content.window.requestAnimationFrame(() =>
+                content.window.requestAnimationFrame(resolve)
+              )
+            );
+          });
+          tester.checkResultAfterTypingA2(expectedData2);
+          tester.clear();
+        }
+      })();
+    }
+  );
+});
diff --git a/widget/tests/browser/browser_test_ime_state_on_editable_state_change_in_remote_content.js b/widget/tests/browser/browser_test_ime_state_on_editable_state_change_in_remote_content.js
new file mode 100644
index 0000000000..8c38f97b72
--- /dev/null
+++ b/widget/tests/browser/browser_test_ime_state_on_editable_state_change_in_remote_content.js
@@ -0,0 +1,297 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from ../file_ime_state_test_helper.js */
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_ime_state_test_helper.js",
+  this
+);
+add_task(async function () {
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/browser/toolkit/content/tests/browser/file_empty.html",
+    async function (browser) {
+      const tipWrapper = new TIPWrapper(window);
+      ok(
+        tipWrapper.isAvailable(),
+        "TextInputProcessor should've been initialized"
+      );
+
+      await SpecialPowers.spawn(browser, [], () => {
+        content.wrappedJSObject.waitForIMEContentObserverSendingNotifications =
+          () => {
+            return new content.window.Promise(resolve =>
+              content.window.requestAnimationFrame(() =>
+                content.window.requestAnimationFrame(resolve)
+              )
+            );
+          };
+        content.wrappedJSObject.resetIMEStateWithFocusMove = () => {
+          const input = content.document.createElement("input");
+          content.document.body.appendChild(input);
+          input.focus();
+          input.remove();
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        };
+        content.document.body.innerHTML = "<div></div>";
+      });
+
+      function resetIMEStateWithFocusMove() {
+        return SpecialPowers.spawn(browser, [], () => {
+          const input = content.document.createElement("input");
+          content.document.body.appendChild(input);
+          input.focus();
+          input.remove();
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+      }
+
+      await (async function test_setting_contenteditable_of_focused_div() {
+        await SpecialPowers.spawn(browser, [], () => {
+          const div = content.document.querySelector("div");
+          div.setAttribute("tabindex", "0");
+          div.focus();
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+          "test_setting_contenteditable_of_focused_div: IME should be disabled when non-editable <div> has focus"
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document
+            .querySelector("div")
+            .setAttribute("contenteditable", "");
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+          "test_setting_contenteditable_of_focused_div: IME should be enabled when contenteditable of focused <div> is set"
+        );
+        ok(
+          tipWrapper.IMEHasFocus,
+          "test_setting_contenteditable_of_focused_div: IME should have focus when contenteditable of focused <div> is set"
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document
+            .querySelector("div")
+            .removeAttribute("contenteditable");
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+          "test_setting_contenteditable_of_focused_div: IME should be disabled when contenteditable of focused <div> is removed"
+        );
+        ok(
+          !tipWrapper.IMEHasFocus,
+          "test_setting_contenteditable_of_focused_div: IME should not have focus when contenteditable of focused <div> is removed"
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document.querySelector("div").removeAttribute("tabindex");
+        });
+      })();
+
+      await resetIMEStateWithFocusMove();
+
+      await (async function test_removing_contenteditable_of_non_last_editable_div() {
+        await SpecialPowers.spawn(browser, [], async () => {
+          const div = content.document.querySelector("div");
+          div.setAttribute("tabindex", "0");
+          div.setAttribute("contenteditable", "");
+          const anotherEditableDiv = content.document.createElement("div");
+          anotherEditableDiv.setAttribute("contenteditable", "");
+          div.parentElement.appendChild(anotherEditableDiv);
+          div.focus();
+          await content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+          div.removeAttribute("contenteditable");
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+          "test_removing_contenteditable_of_non_last_editable_div: IME should be disabled when contenteditable of focused <div> is removed"
+        );
+        ok(
+          !tipWrapper.IMEHasFocus,
+          "test_removing_contenteditable_of_non_last_editable_div: IME should not have focus when contenteditable of focused <div> is removed"
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          const divs = content.document.querySelectorAll("div");
+          divs[1].remove();
+          divs[0].removeAttribute("tabindex");
+        });
+      })();
+
+      await resetIMEStateWithFocusMove();
+
+      await (async function test_setting_designMode() {
+        await SpecialPowers.spawn(browser, [], () => {
+          content.window.focus();
+          content.document.designMode = "on";
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+          'test_setting_designMode: IME should be enabled when designMode is set to "on"'
+        );
+        ok(
+          tipWrapper.IMEHasFocus,
+          'test_setting_designMode: IME should have focus when designMode is set to "on"'
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document.designMode = "off";
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+          'test_setting_designMode: IME should be disabled when designMode is set to "off"'
+        );
+        ok(
+          !tipWrapper.IMEHasFocus,
+          'test_setting_designMode: IME should not have focus when designMode is set to "off"'
+        );
+      })();
+
+      await resetIMEStateWithFocusMove();
+
+      async function test_setting_content_editable_of_body_when_shadow_DOM_has_focus(
+        aMode
+      ) {
+        await SpecialPowers.spawn(browser, [aMode], mode => {
+          const div = content.document.querySelector("div");
+          const shadow = div.attachShadow({ mode });
+          content.wrappedJSObject.divInShadow =
+            content.document.createElement("div");
+          content.wrappedJSObject.divInShadow.setAttribute("tabindex", "0");
+          shadow.appendChild(content.wrappedJSObject.divInShadow);
+          content.wrappedJSObject.divInShadow.focus();
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+          `test_setting_content_editable_of_body_when_shadow_DOM_has_focus(${aMode}): IME should be disabled when non-editable <div> in a shadow DOM has focus`
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document.body.setAttribute("contenteditable", "");
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        // todo_is because of bug 1807597.  Gecko does not update focus when focused
+        // element becomes an editable child.  Therefore, cannot initialize
+        // HTMLEditor with the new editing host.
+        todo_is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+          `test_setting_content_editable_of_body_when_shadow_DOM_has_focus(${aMode}): IME should be enabled when the <body> becomes editable`
+        );
+        todo(
+          tipWrapper.IMEHasFocus,
+          `test_setting_content_editable_of_body_when_shadow_DOM_has_focus(${aMode}): IME should have focus when the <body> becomes editable`
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document.body.removeAttribute("contenteditable");
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+          `test_setting_content_editable_of_body_when_shadow_DOM_has_focus)${aMode}): IME should be disabled when the <body> becomes not editable`
+        );
+        ok(
+          !tipWrapper.IMEHasFocus,
+          `test_setting_content_editable_of_body_when_shadow_DOM_has_focus)${aMode}): IME should not have focus when the <body> becomes not editable`
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document.querySelector("div").remove();
+          content.document.body.appendChild(
+            content.document.createElement("div")
+          );
+        });
+      }
+
+      async function test_setting_designMode_when_shadow_DOM_has_focus(aMode) {
+        await SpecialPowers.spawn(browser, [aMode], mode => {
+          const div = content.document.querySelector("div");
+          const shadow = div.attachShadow({ mode });
+          content.wrappedJSObject.divInShadow =
+            content.document.createElement("div");
+          content.wrappedJSObject.divInShadow.setAttribute("tabindex", "0");
+          shadow.appendChild(content.wrappedJSObject.divInShadow);
+          content.wrappedJSObject.divInShadow.focus();
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+          `test_setting_designMode_when_shadow_DOM_has_focus(${aMode}): IME should be disabled when non-editable <div> in a shadow DOM has focus`
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document.designMode = "on";
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+          `test_setting_designMode_when_shadow_DOM_has_focus(${aMode}): IME should stay disabled when designMode is set`
+        );
+        ok(
+          !tipWrapper.IMEHasFocus,
+          `test_setting_designMode_when_shadow_DOM_has_focus(${aMode}): IME should not have focus when designMode is set`
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          content.wrappedJSObject.divInShadow.setAttribute(
+            "contenteditable",
+            ""
+          );
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        // todo_is because of bug 1807597.  Gecko does not update focus when focused
+        // document is into the design mode.  Therefore, cannot initialize
+        // HTMLEditor with the document node properly.
+        todo_is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+          `test_setting_designMode_when_shadow_DOM_has_focus(${aMode}): IME should be enabled when focused <div> in a shadow DOM becomes editable`
+        );
+        todo(
+          tipWrapper.IMEHasFocus,
+          `test_setting_designMode_when_shadow_DOM_has_focus(${aMode}): IME should have focus when focused <div> in a shadow DOM becomes editable`
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document.designMode = "off";
+          return content.wrappedJSObject.waitForIMEContentObserverSendingNotifications();
+        });
+        is(
+          window.windowUtils.IMEStatus,
+          Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+          `test_setting_designMode_when_shadow_DOM_has_focus(${aMode}): IME should be disabled when designMode is unset`
+        );
+        ok(
+          !tipWrapper.IMEHasFocus,
+          `test_setting_designMode_when_shadow_DOM_has_focus(${aMode}): IME should not have focus when designMode is unset`
+        );
+        await SpecialPowers.spawn(browser, [], () => {
+          content.document.querySelector("div").remove();
+          content.document.body.appendChild(
+            content.document.createElement("div")
+          );
+        });
+      }
+
+      for (const mode of ["open", "closed"]) {
+        await test_setting_content_editable_of_body_when_shadow_DOM_has_focus(
+          mode
+        );
+        await resetIMEStateWithFocusMove();
+        await test_setting_designMode_when_shadow_DOM_has_focus(mode);
+        await resetIMEStateWithFocusMove();
+      }
+    }
+  );
+});
diff --git a/widget/tests/browser/browser_test_ime_state_on_focus_move_in_remote_content.js b/widget/tests/browser/browser_test_ime_state_on_focus_move_in_remote_content.js
new file mode 100644
index 0000000000..3916d3d47c
--- /dev/null
+++ b/widget/tests/browser/browser_test_ime_state_on_focus_move_in_remote_content.js
@@ -0,0 +1,128 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from ../file_ime_state_test_helper.js */
+/* import-globals-from ../file_test_ime_state_on_focus_move.js */
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_ime_state_test_helper.js",
+  this
+);
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_test_ime_state_on_focus_move.js",
+  this
+);
+add_task(async function () {
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/browser/widget/tests/browser/file_ime_state_tests.html",
+    async function (browser) {
+      const tipWrapper = new TIPWrapper(window);
+      ok(
+        tipWrapper.isAvailable(),
+        "TextInputProcessor should've been initialized"
+      );
+
+      // isnot is used in file_test_ime_state_on_focus_move.js, but it's not
+      // defined as the alias of Assert.notEqual in browser-chrome tests.
+      // Therefore, we need to define it here.
+      // eslint-disable-next-line no-unused-vars
+      const isnot = Assert.notEqual;
+
+      async function runIMEStateOnFocusMoveTests(aDescription) {
+        await (async function test_IMEState_without_focused_element() {
+          const checker = new IMEStateWhenNoActiveElementTester(aDescription);
+          const expectedData = await SpecialPowers.spawn(
+            browser,
+            [aDescription],
+            description => {
+              const runner =
+                content.wrappedJSObject.createIMEStateWhenNoActiveElementTester(
+                  description
+                );
+              return runner.run(content.document, content.window);
+            }
+          );
+          checker.check(expectedData);
+        })();
+        for (
+          let index = 0;
+          index < IMEStateOnFocusMoveTester.numberOfTests;
+          ++index
+        ) {
+          const checker = new IMEStateOnFocusMoveTester(aDescription, index);
+          const expectedData = await SpecialPowers.spawn(
+            browser,
+            [aDescription, index],
+            (description, aIndex) => {
+              content.wrappedJSObject.runner =
+                content.wrappedJSObject.createIMEStateOnFocusMoveTester(
+                  description,
+                  aIndex,
+                  content.window
+                );
+              return content.wrappedJSObject.runner.prepareToRun(
+                content.document.querySelector("div")
+              );
+            }
+          );
+          checker.prepareToCheck(expectedData, tipWrapper);
+          await SpecialPowers.spawn(browser, [], () => {
+            return content.wrappedJSObject.runner.run();
+          });
+          checker.check(expectedData);
+
+          if (checker.canTestOpenCloseState(expectedData)) {
+            for (const defaultOpenState of [false, true]) {
+              const expectedOpenStateData = await SpecialPowers.spawn(
+                browser,
+                [],
+                () => {
+                  return content.wrappedJSObject.runner.prepareToRunOpenCloseTest(
+                    content.document.querySelector("div")
+                  );
+                }
+              );
+              checker.prepareToCheckOpenCloseTest(
+                defaultOpenState,
+                expectedOpenStateData
+              );
+              await SpecialPowers.spawn(browser, [], () => {
+                return content.wrappedJSObject.runner.runOpenCloseTest();
+              });
+              checker.checkOpenCloseTest(expectedOpenStateData);
+            }
+          }
+          await SpecialPowers.spawn(browser, [], () => {
+            content.wrappedJSObject.runner.destroy();
+            content.wrappedJSObject.runner = undefined;
+          });
+          checker.destroy();
+        } // for loop iterating test of IMEStateOnFocusMoveTester
+      } // definition of runIMEStateOnFocusMoveTests
+
+      // test for normal contents.
+      await runIMEStateOnFocusMoveTests("in non-editable container");
+
+      // test for removing contentEditable
+      await SpecialPowers.spawn(browser, [], async () => {
+        content.document
+          .querySelector("div")
+          .setAttribute("contenteditable", "true");
+        content.document.querySelector("div").focus();
+        await new Promise(resolve =>
+          content.window.requestAnimationFrame(() =>
+            content.window.requestAnimationFrame(resolve)
+          )
+        );
+        content.document
+          .querySelector("div")
+          .removeAttribute("contenteditable");
+      });
+      await runIMEStateOnFocusMoveTests(
+        "after removing contenteditable from the container"
+      );
+    }
+  );
+});
diff --git a/widget/tests/browser/browser_test_ime_state_on_input_type_change_in_remote_content.js b/widget/tests/browser/browser_test_ime_state_on_input_type_change_in_remote_content.js
new file mode 100644
index 0000000000..2a4bc4c332
--- /dev/null
+++ b/widget/tests/browser/browser_test_ime_state_on_input_type_change_in_remote_content.js
@@ -0,0 +1,70 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from ../file_ime_state_test_helper.js */
+/* import-globals-from ../file_test_ime_state_on_input_type_change.js */
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_ime_state_test_helper.js",
+  this
+);
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_test_ime_state_on_input_type_change.js",
+  this
+);
+add_task(async function () {
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/browser/widget/tests/browser/file_ime_state_tests.html",
+    async function (browser) {
+      const tipWrapper = new TIPWrapper(window);
+      ok(
+        tipWrapper.isAvailable(),
+        "TextInputProcessor should've been initialized"
+      );
+
+      for (
+        let srcIndex = 0;
+        srcIndex < IMEStateOnInputTypeChangeTester.numberOfTests;
+        srcIndex++
+      ) {
+        const tester = new IMEStateOnInputTypeChangeTester(srcIndex);
+        for (
+          let destIndex = 0;
+          destIndex < IMEStateOnInputTypeChangeTester.numberOfTests;
+          destIndex++
+        ) {
+          const expectedResultBefore = await SpecialPowers.spawn(
+            browser,
+            [srcIndex, destIndex],
+            (aSrcIndex, aDestIndex) => {
+              content.wrappedJSObject.runner =
+                content.wrappedJSObject.createIMEStateOnInputTypeChangeTester(
+                  aSrcIndex
+                );
+              return content.wrappedJSObject.runner.prepareToRun(
+                aDestIndex,
+                content.window,
+                content.document.body
+              );
+            }
+          );
+          if (expectedResultBefore === false) {
+            continue;
+          }
+          tester.checkBeforeRun(expectedResultBefore, tipWrapper);
+          const expectedResult = await SpecialPowers.spawn(browser, [], () => {
+            return content.wrappedJSObject.runner.run();
+          });
+          tester.checkResult(expectedResultBefore, expectedResult);
+          await SpecialPowers.spawn(browser, [], () => {
+            return content.wrappedJSObject.runner.clear();
+          });
+          tipWrapper.clearFocusBlurNotifications();
+        }
+        tester.clear();
+      }
+    }
+  );
+});
diff --git a/widget/tests/browser/browser_test_ime_state_on_readonly_change_in_remote_content.js b/widget/tests/browser/browser_test_ime_state_on_readonly_change_in_remote_content.js
new file mode 100644
index 0000000000..a0c0019328
--- /dev/null
+++ b/widget/tests/browser/browser_test_ime_state_on_readonly_change_in_remote_content.js
@@ -0,0 +1,68 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from ../file_ime_state_test_helper.js */
+/* import-globals-from ../file_test_ime_state_on_readonly_change.js */
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_ime_state_test_helper.js",
+  this
+);
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/widget/tests/browser/file_test_ime_state_on_readonly_change.js",
+  this
+);
+add_task(async function () {
+  await BrowserTestUtils.withNewTab(
+    "https://example.com/browser/widget/tests/browser/file_ime_state_tests.html",
+    async function (browser) {
+      const tipWrapper = new TIPWrapper(window);
+      ok(
+        tipWrapper.isAvailable(),
+        "TextInputProcessor should've been initialized"
+      );
+
+      const tester = new IMEStateOnReadonlyChangeTester();
+      for (
+        let i = 0;
+        i < IMEStateOnReadonlyChangeTester.numberOfTextControlTypes;
+        i++
+      ) {
+        const expectedResultBefore = await SpecialPowers.spawn(
+          browser,
+          [i],
+          aIndex => {
+            content.wrappedJSObject.runner =
+              content.wrappedJSObject.createIMEStateOnReadonlyChangeTester(
+                aIndex
+              );
+            return content.wrappedJSObject.runner.prepareToRun(
+              aIndex,
+              content.window,
+              content.document.body
+            );
+          }
+        );
+        tester.checkBeforeRun(expectedResultBefore, tipWrapper);
+        const expectedResultOfMakingTextControlReadonly =
+          await SpecialPowers.spawn(browser, [], () => {
+            return content.wrappedJSObject.runner.runToMakeTextControlReadonly();
+          });
+        tester.checkResultOfMakingTextControlReadonly(
+          expectedResultOfMakingTextControlReadonly
+        );
+        const expectedResultOfMakingTextControlEditable =
+          await SpecialPowers.spawn(browser, [], () => {
+            return content.wrappedJSObject.runner.runToMakeTextControlEditable();
+          });
+        tester.checkResultOfMakingTextControlEditable(
+          expectedResultOfMakingTextControlEditable
+        );
+        tipWrapper.clearFocusBlurNotifications();
+        tester.clear();
+      }
+    }
+  );
+});
diff --git a/widget/tests/browser/browser_test_scrollbar_colors.js b/widget/tests/browser/browser_test_scrollbar_colors.js
new file mode 100644
index 0000000000..2152412071
--- /dev/null
+++ b/widget/tests/browser/browser_test_scrollbar_colors.js
@@ -0,0 +1,146 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+
+"use strict";
+
+add_task(async () => {
+  const URL_ROOT = getRootDirectory(gTestPath).replace(
+    "chrome://mochitests/content/",
+    "http://mochi.test:8888/"
+  );
+
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    URL_ROOT + "helper_scrollbar_colors.html"
+  );
+
+  await SpecialPowers.spawn(tab.linkedBrowser, [], () => {
+    ChromeUtils.defineESModuleGetters(this, {
+      WindowsVersionInfo:
+        "resource://gre/modules/components-utils/WindowsVersionInfo.sys.mjs",
+    });
+
+    Services.scriptloader.loadSubScript(
+      "chrome://mochikit/content/tests/SimpleTest/WindowSnapshot.js",
+      this
+    );
+
+    // == Native theme ==
+
+    const WIN_REFERENCES = [
+      // Yellow background
+      ["255,255,0", 6889],
+      // Blue scrollbar face
+      ["0,0,255", 540],
+      // Cyan scrollbar track
+      ["0,255,255", 2487],
+    ];
+
+    const MAC_REFERENCES = [
+      // Yellow background
+      ["255,255,0", 7225],
+      // Blue scrollbar face
+      ["0,0,255", 416],
+      // Cyan scrollbar track
+      ["0,255,255", 1760],
+    ];
+
+    // Values have been updated from 8100, 720, 1180 for linux1804
+    const LINUX_REFERENCES = [
+      // Yellow background
+      ["255,255,0", 7744],
+      // Blue scrollbar face
+      ["0,0,255", 1104],
+      // Cyan scrollbar track
+      ["0,255,255", 1152],
+    ];
+
+    // == Non-native theme ==
+
+    const WIN10_NNT_REFERENCES = [
+      // Yellow background
+      ["255,255,0", 6889],
+      // Blue scrollbar face
+      ["0,0,255", 612],
+      // Cyan scrollbar track
+      ["0,255,255", 2355],
+    ];
+
+    const WIN11_NNT_REFERENCES = [
+      // Yellow background
+      ["255,255,0", 6889],
+      // Blue scrollbar face
+      ["0,0,255", 324],
+      // Cyan scrollbar track
+      ["0,255,255", 2787],
+    ];
+
+    const MAC_NNT_REFERENCES = MAC_REFERENCES;
+
+    const LINUX_NNT_REFERENCES = [
+      // Yellow background
+      ["255,255,0", 7744],
+      // Blue scrollbar face
+      ["0,0,255", 368],
+      // Cyan scrollbar track
+      ["0,255,255", 1852],
+    ];
+
+    function countPixels(canvas) {
+      let result = new Map();
+      let ctx = canvas.getContext("2d");
+      let image = ctx.getImageData(0, 0, canvas.width, canvas.height);
+      let data = image.data;
+      let size = image.width * image.height;
+      for (let i = 0; i < size; i++) {
+        let key = data.subarray(i * 4, i * 4 + 3).toString();
+        let value = result.get(key);
+        value = value ? value : 0;
+        result.set(key, value + 1);
+      }
+      return result;
+    }
+
+    let outer = content.document.querySelector(".outer");
+    let outerRect = outer.getBoundingClientRect();
+    if (
+      outerRect.width == outer.clientWidth &&
+      outerRect.height == outer.clientHeight
+    ) {
+      ok(true, "Using overlay scrollbar, skip this test");
+      return;
+    }
+    content.document.querySelector("#style").textContent = `
+        .outer { scrollbar-color: blue cyan; }
+      `;
+
+    let canvas = snapshotRect(content.window, outerRect);
+    let stats = countPixels(canvas);
+    let isNNT = SpecialPowers.getBoolPref("widget.non-native-theme.enabled");
+
+    let references;
+    if (content.navigator.platform.startsWith("Win")) {
+      if (!isNNT) {
+        references = WIN_REFERENCES;
+      } else if (WindowsVersionInfo.get().buildNumber >= 22000) {
+        // Windows 11 NNT
+        references = WIN11_NNT_REFERENCES;
+      } else {
+        // Windows 10 NNT
+        references = WIN10_NNT_REFERENCES;
+      }
+    } else if (content.navigator.platform.startsWith("Mac")) {
+      references = isNNT ? MAC_NNT_REFERENCES : MAC_REFERENCES;
+    } else if (content.navigator.platform.startsWith("Linux")) {
+      references = isNNT ? LINUX_NNT_REFERENCES : LINUX_REFERENCES;
+    } else {
+      ok(false, "Unsupported platform");
+    }
+    for (let [color, count] of references) {
+      let value = stats.get(color);
+      is(value, count, `Pixel count of color ${color}`);
+    }
+  });
+
+  BrowserTestUtils.removeTab(tab);
+});
diff --git a/widget/tests/browser/browser_test_swipe_gesture.js b/widget/tests/browser/browser_test_swipe_gesture.js
new file mode 100644
index 0000000000..0ac85d80c8
--- /dev/null
+++ b/widget/tests/browser/browser_test_swipe_gesture.js
@@ -0,0 +1,1274 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+
+"use strict";
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/gfx/layers/apz/test/mochitest/apz_test_utils.js",
+  this
+);
+
+Services.scriptloader.loadSubScript(
+  "chrome://mochitests/content/browser/gfx/layers/apz/test/mochitest/apz_test_native_event_utils.js",
+  this
+);
+
+async function waitForWhile() {
+  await new Promise(resolve => {
+    requestIdleCallback(resolve, { timeout: 300 });
+  });
+  await new Promise(r => requestAnimationFrame(r));
+}
+
+requestLongerTimeout(2);
+
+add_task(async () => {
+  // Set the default values for an OS that supports swipe to nav, except for
+  // pixel-size which varies by OS, we vary it in differente tests in this file.
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      // Set the velocity-contribution to 0 so we can exactly control the
+      // values in the swipe tracker via the delta in the events that we send.
+      ["widget.swipe.success-velocity-contribution", 0.0],
+      ["widget.swipe.pixel-size", 550.0],
+    ],
+  });
+
+  const firstPage = "about:about";
+  const secondPage = "about:mozilla";
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    firstPage,
+    true /* waitForLoad */
+  );
+
+  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, secondPage);
+  await BrowserTestUtils.browserLoaded(tab.linkedBrowser, false, secondPage);
+
+  // Make sure we can go back to the previous page.
+  ok(gBrowser.webNavigation.canGoBack);
+  // and we cannot go forward to the next page.
+  ok(!gBrowser.webNavigation.canGoForward);
+
+  let wheelEventCount = 0;
+  tab.linkedBrowser.addEventListener("wheel", () => {
+    wheelEventCount++;
+  });
+
+  // Send a pan that starts a navigate back but doesn't have enough delta to do
+  // anything. Don't send the pan end because we want to check the opacity
+  // before the MSD animation in SwipeTracker starts which can temporarily put
+  // us at 1 opacity.
+  await panLeftToRightBegin(tab.linkedBrowser, 100, 100, 0.9);
+  await panLeftToRightUpdate(tab.linkedBrowser, 100, 100, 0.9);
+
+  // Check both getComputedStyle instead of element.style.opacity because we use a transition on the opacity.
+  let computedOpacity = window
+    .getComputedStyle(gHistorySwipeAnimation._prevBox)
+    .getPropertyValue("opacity");
+  is(computedOpacity, "1", "opacity of prevbox is 1");
+  let opacity = gHistorySwipeAnimation._prevBox.style.opacity;
+  is(opacity, "", "opacity style isn't explicitly set");
+
+  const isTranslatingIcon =
+    Services.prefs.getIntPref(
+      "browser.swipe.navigation-icon-start-position",
+      0
+    ) != 0 ||
+    Services.prefs.getIntPref(
+      "browser.swipe.navigation-icon-end-position",
+      0
+    ) != 0;
+  if (isTranslatingIcon != 0) {
+    isnot(
+      window
+        .getComputedStyle(gHistorySwipeAnimation._prevBox)
+        .getPropertyValue("translate"),
+      "none",
+      "translate of prevbox is not `none` during gestures"
+    );
+  }
+
+  await panLeftToRightEnd(tab.linkedBrowser, 100, 100, 0.9);
+
+  // NOTE: We only get a wheel event for the beginPhase, rest of events have
+  // been captured by the swipe gesture module.
+  is(wheelEventCount, 1, "Received a wheel event");
+
+  await waitForWhile();
+  // Make sure any navigation didn't happen.
+  is(tab.linkedBrowser.currentURI.spec, secondPage);
+
+  // Try to navigate backward.
+  wheelEventCount = 0;
+  let startLoadingPromise = BrowserTestUtils.browserStarted(
+    tab.linkedBrowser,
+    firstPage
+  );
+  let stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+    tab.linkedBrowser,
+    firstPage
+  );
+  await panLeftToRight(tab.linkedBrowser, 100, 100, 1);
+  // NOTE: We only get a wheel event for the beginPhase, rest of events have
+  // been captured by the swipe gesture module.
+  is(wheelEventCount, 1, "Received a wheel event");
+
+  // The element.style opacity will be 0 because we set it to 0 on successful navigation, however
+  // we have a tranisition on it so the computed style opacity will still be 1 because the transition hasn't started yet.
+  computedOpacity = window
+    .getComputedStyle(gHistorySwipeAnimation._prevBox)
+    .getPropertyValue("opacity");
+  ok(computedOpacity == 1, "computed opacity of prevbox is 1");
+  opacity = gHistorySwipeAnimation._prevBox.style.opacity;
+  ok(opacity == 0, "element.style opacity of prevbox 0");
+
+  if (isTranslatingIcon) {
+    // We don't have a transition for translate property so that we still have
+    // some amount of translate.
+    isnot(
+      window
+        .getComputedStyle(gHistorySwipeAnimation._prevBox)
+        .getPropertyValue("translate"),
+      "none",
+      "translate of prevbox is not `none` during the opacity transition"
+    );
+  }
+
+  // Make sure the gesture triggered going back to the previous page.
+  await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+  ok(gBrowser.webNavigation.canGoForward);
+
+  BrowserTestUtils.removeTab(tab);
+  await SpecialPowers.popPrefEnv();
+});
+
+// Same test as above but pixel-size is increased and the multipliers passed to panLeftToRight correspondingly increased.
+add_task(async () => {
+  // Set the default values for an OS that supports swipe to nav, except for
+  // pixel-size which varies by OS, we vary it in differente tests
+  // in this file.
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      // Set the velocity-contribution to 0 so we can exactly control the
+      // values in the swipe tracker via the delta in the events that we send.
+      ["widget.swipe.success-velocity-contribution", 0.0],
+      ["widget.swipe.pixel-size", 1100.0],
+    ],
+  });
+
+  const firstPage = "about:about";
+  const secondPage = "about:mozilla";
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    firstPage,
+    true /* waitForLoad */
+  );
+
+  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, secondPage);
+  await BrowserTestUtils.browserLoaded(tab.linkedBrowser, false, secondPage);
+
+  // Make sure we can go back to the previous page.
+  ok(gBrowser.webNavigation.canGoBack);
+  // and we cannot go forward to the next page.
+  ok(!gBrowser.webNavigation.canGoForward);
+
+  let wheelEventCount = 0;
+  tab.linkedBrowser.addEventListener("wheel", () => {
+    wheelEventCount++;
+  });
+
+  // Send a pan that starts a navigate back but doesn't have enough delta to do
+  // anything. Don't send the pan end because we want to check the opacity
+  // before the MSD animation in SwipeTracker starts which can temporarily put
+  // us at 1 opacity.
+  await panLeftToRightBegin(tab.linkedBrowser, 100, 100, 1.8);
+  await panLeftToRightUpdate(tab.linkedBrowser, 100, 100, 1.8);
+
+  // Check both getComputedStyle instead of element.style.opacity because we use a transition on the opacity.
+  let computedOpacity = window
+    .getComputedStyle(gHistorySwipeAnimation._prevBox)
+    .getPropertyValue("opacity");
+  is(computedOpacity, "1", "opacity of prevbox is 1");
+  let opacity = gHistorySwipeAnimation._prevBox.style.opacity;
+  is(opacity, "", "opacity style isn't explicitly set");
+
+  await panLeftToRightEnd(tab.linkedBrowser, 100, 100, 1.8);
+
+  // NOTE: We only get a wheel event for the beginPhase, rest of events have
+  // been captured by the swipe gesture module.
+  is(wheelEventCount, 1, "Received a wheel event");
+
+  await waitForWhile();
+  // Make sure any navigation didn't happen.
+  is(tab.linkedBrowser.currentURI.spec, secondPage);
+
+  // Try to navigate backward.
+  wheelEventCount = 0;
+  let startLoadingPromise = BrowserTestUtils.browserStarted(
+    tab.linkedBrowser,
+    firstPage
+  );
+  let stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+    tab.linkedBrowser,
+    firstPage
+  );
+  await panLeftToRight(tab.linkedBrowser, 100, 100, 2);
+  // NOTE: We only get a wheel event for the beginPhase, rest of events have
+  // been captured by the swipe gesture module.
+  is(wheelEventCount, 1, "Received a wheel event");
+
+  // The element.style opacity will be 0 because we set it to 0 on successful navigation, however
+  // we have a tranisition on it so the computed style opacity will still be 1 because the transition hasn't started yet.
+  computedOpacity = window
+    .getComputedStyle(gHistorySwipeAnimation._prevBox)
+    .getPropertyValue("opacity");
+  ok(computedOpacity == 1, "computed opacity of prevbox is 1");
+  opacity = gHistorySwipeAnimation._prevBox.style.opacity;
+  ok(opacity == 0, "element.style opacity of prevbox 0");
+
+  // Make sure the gesture triggered going back to the previous page.
+  await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+  ok(gBrowser.webNavigation.canGoForward);
+
+  BrowserTestUtils.removeTab(tab);
+  await SpecialPowers.popPrefEnv();
+});
+
+add_task(async () => {
+  // Set the default values for an OS that supports swipe to nav, except for
+  // pixel-size which varies by OS, we vary it in different tests
+  // in this file.
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      // Set the velocity-contribution to 1 (default 0.05f) so velocity is a
+      // large contribution to the success value in SwipeTracker.cpp so it
+      // pushes us into success territory without going into success territory
+      // purely from th deltas.
+      ["widget.swipe.success-velocity-contribution", 2.0],
+      ["widget.swipe.pixel-size", 550.0],
+    ],
+  });
+
+  async function runTest() {
+    const firstPage = "about:about";
+    const secondPage = "about:mozilla";
+    const tab = await BrowserTestUtils.openNewForegroundTab(
+      gBrowser,
+      firstPage,
+      true /* waitForLoad */
+    );
+
+    BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, secondPage);
+    await BrowserTestUtils.browserLoaded(tab.linkedBrowser, false, secondPage);
+
+    // Make sure we can go back to the previous page.
+    ok(gBrowser.webNavigation.canGoBack);
+    // and we cannot go forward to the next page.
+    ok(!gBrowser.webNavigation.canGoForward);
+
+    let wheelEventCount = 0;
+    tab.linkedBrowser.addEventListener("wheel", () => {
+      wheelEventCount++;
+    });
+
+    let startLoadingPromise = BrowserTestUtils.browserStarted(
+      tab.linkedBrowser,
+      firstPage
+    );
+    let stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+      tab.linkedBrowser,
+      firstPage
+    );
+    let startTime = performance.now();
+    await panLeftToRight(tab.linkedBrowser, 100, 100, 0.2);
+    let endTime = performance.now();
+
+    // If sending the events took too long then we might not have been able
+    // to generate enough velocity.
+    // The value 230 was picked based on try runs, in particular test verify
+    // runs on mac were the long pole, and when we get times near this we can
+    // still achieve the required velocity.
+    if (endTime - startTime > 230) {
+      BrowserTestUtils.removeTab(tab);
+      return false;
+    }
+
+    // NOTE: We only get a wheel event for the beginPhase, rest of events have
+    // been captured by the swipe gesture module.
+    is(wheelEventCount, 1, "Received a wheel event");
+
+    // The element.style opacity will be 0 because we set it to 0 on successful navigation, however
+    // we have a tranisition on it so the computed style opacity will still be 1 because the transition hasn't started yet.
+    let computedOpacity = window
+      .getComputedStyle(gHistorySwipeAnimation._prevBox)
+      .getPropertyValue("opacity");
+    ok(computedOpacity == 1, "computed opacity of prevbox is 1");
+    let opacity = gHistorySwipeAnimation._prevBox.style.opacity;
+    ok(opacity == 0, "element.style opacity of prevbox 0");
+
+    // Make sure the gesture triggered going back to the previous page.
+    await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+    ok(gBrowser.webNavigation.canGoForward);
+
+    BrowserTestUtils.removeTab(tab);
+
+    return true;
+  }
+
+  let numTries = 15;
+  while (numTries > 0) {
+    await new Promise(r => requestAnimationFrame(r));
+    await new Promise(resolve => requestIdleCallback(resolve));
+    await new Promise(r => requestAnimationFrame(r));
+
+    // runTest return value indicates if test was able to run to the end.
+    if (await runTest()) {
+      break;
+    }
+    numTries--;
+  }
+  ok(numTries > 0, "never ran the test");
+  await SpecialPowers.popPrefEnv();
+});
+
+add_task(async () => {
+  // Set the default values for an OS that supports swipe to nav, except for
+  // pixel-size which varies by OS, we vary it in differente tests
+  // in this file.
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      // Set the velocity-contribution to 0 so we can exactly control the
+      // values in the swipe tracker via the delta in the events that we send.
+      ["widget.swipe.success-velocity-contribution", 0.0],
+      ["widget.swipe.pixel-size", 550.0],
+    ],
+  });
+
+  const firstPage = "about:about";
+  const secondPage = "about:mozilla";
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    firstPage,
+    true /* waitForLoad */
+  );
+
+  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, secondPage);
+  await BrowserTestUtils.browserLoaded(tab.linkedBrowser, false, secondPage);
+
+  // Make sure we can go back to the previous page.
+  ok(gBrowser.webNavigation.canGoBack);
+  // and we cannot go forward to the next page.
+  ok(!gBrowser.webNavigation.canGoForward);
+
+  let startLoadingPromise = BrowserTestUtils.browserStarted(
+    tab.linkedBrowser,
+    firstPage
+  );
+  let stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+    tab.linkedBrowser,
+    firstPage
+  );
+  await panLeftToRight(tab.linkedBrowser, 100, 100, 2);
+
+  // Make sure the gesture triggered going back to the previous page.
+  await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+  ok(gBrowser.webNavigation.canGoForward);
+
+  while (
+    gHistorySwipeAnimation._prevBox != null ||
+    gHistorySwipeAnimation._nextBox != null
+  ) {
+    await new Promise(r => requestAnimationFrame(r));
+  }
+
+  ok(
+    gHistorySwipeAnimation._prevBox == null &&
+      gHistorySwipeAnimation._nextBox == null
+  );
+
+  BrowserTestUtils.removeTab(tab);
+  await SpecialPowers.popPrefEnv();
+});
+
+add_task(async () => {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      // Set the velocity-contribution to 0 so we can exactly control the
+      // values in the swipe tracker via the delta in the events that we send.
+      ["widget.swipe.success-velocity-contribution", 0.0],
+      ["widget.swipe.pixel-size", 550.0],
+    ],
+  });
+
+  function swipeGestureEndPromise() {
+    return new Promise(resolve => {
+      let promiseObserver = {
+        handleEvent(aEvent) {
+          switch (aEvent.type) {
+            case "MozSwipeGestureEnd":
+              gBrowser.tabbox.removeEventListener(
+                "MozSwipeGestureEnd",
+                promiseObserver,
+                true
+              );
+              resolve();
+              break;
+          }
+        },
+      };
+      gBrowser.tabbox.addEventListener(
+        "MozSwipeGestureEnd",
+        promiseObserver,
+        true
+      );
+    });
+  }
+
+  const firstPage = "about:about";
+  const secondPage = "about:mozilla";
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    firstPage,
+    true /* waitForLoad */
+  );
+
+  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, secondPage);
+  await BrowserTestUtils.browserLoaded(tab.linkedBrowser, false, secondPage);
+
+  // Make sure we can go back to the previous page.
+  ok(gBrowser.webNavigation.canGoBack);
+  // and we cannot go forward to the next page.
+  ok(!gBrowser.webNavigation.canGoForward);
+
+  let numSwipeGestureEndEvents = 0;
+  var anObserver = {
+    handleEvent(aEvent) {
+      switch (aEvent.type) {
+        case "MozSwipeGestureEnd":
+          numSwipeGestureEndEvents++;
+          break;
+      }
+    },
+  };
+
+  gBrowser.tabbox.addEventListener("MozSwipeGestureEnd", anObserver, true);
+
+  let gestureEndPromise = swipeGestureEndPromise();
+
+  is(
+    numSwipeGestureEndEvents,
+    0,
+    "expected no MozSwipeGestureEnd got " + numSwipeGestureEndEvents
+  );
+
+  // Send a pan that starts a navigate back but doesn't have enough delta to do
+  // anything.
+  await panLeftToRight(tab.linkedBrowser, 100, 100, 0.9);
+
+  await waitForWhile();
+  // Make sure any navigation didn't happen.
+  is(tab.linkedBrowser.currentURI.spec, secondPage);
+  // end event comes after a swipe that does not navigate
+  await gestureEndPromise;
+  is(
+    numSwipeGestureEndEvents,
+    1,
+    "expected one MozSwipeGestureEnd got " + numSwipeGestureEndEvents
+  );
+
+  // Try to navigate backward.
+  let startLoadingPromise = BrowserTestUtils.browserStarted(
+    tab.linkedBrowser,
+    firstPage
+  );
+  let stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+    tab.linkedBrowser,
+    firstPage
+  );
+
+  gestureEndPromise = swipeGestureEndPromise();
+
+  await panLeftToRight(tab.linkedBrowser, 100, 100, 1);
+
+  // Make sure the gesture triggered going back to the previous page.
+  await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+  ok(gBrowser.webNavigation.canGoForward);
+
+  await gestureEndPromise;
+
+  is(
+    numSwipeGestureEndEvents,
+    2,
+    "expected one MozSwipeGestureEnd got " + (numSwipeGestureEndEvents - 1)
+  );
+
+  gBrowser.tabbox.removeEventListener("MozSwipeGestureEnd", anObserver, true);
+
+  BrowserTestUtils.removeTab(tab);
+  await SpecialPowers.popPrefEnv();
+});
+
+add_task(async () => {
+  // success-velocity-contribution is very high and pixel-size is
+  // very low so that one swipe goes over the threshold asap.
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      ["widget.swipe.success-velocity-contribution", 999999.0],
+      ["widget.swipe.pixel-size", 1.0],
+    ],
+  });
+
+  const firstPage = "about:about";
+  const secondPage = "about:mozilla";
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    firstPage,
+    true /* waitForLoad */
+  );
+
+  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, secondPage);
+  await BrowserTestUtils.browserLoaded(tab.linkedBrowser, false, secondPage);
+
+  // Make sure we can go back to the previous page.
+  ok(gBrowser.webNavigation.canGoBack);
+  // and we cannot go forward to the next page.
+  ok(!gBrowser.webNavigation.canGoForward);
+
+  // Navigate backward.
+  let startLoadingPromise = BrowserTestUtils.browserStarted(
+    tab.linkedBrowser,
+    firstPage
+  );
+  let stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+    tab.linkedBrowser,
+    firstPage
+  );
+
+  await panLeftToRightBegin(tab.linkedBrowser, 100, 100, 100);
+
+  ok(gHistorySwipeAnimation._prevBox != null, "should have prevbox");
+  let transitionCancelPromise = new Promise(resolve => {
+    gHistorySwipeAnimation._prevBox.addEventListener(
+      "transitioncancel",
+      event => {
+        if (
+          event.propertyName == "opacity" &&
+          event.target == gHistorySwipeAnimation._prevBox
+        ) {
+          resolve();
+        }
+      },
+      { once: true }
+    );
+  });
+  let transitionStartPromise = new Promise(resolve => {
+    gHistorySwipeAnimation._prevBox.addEventListener(
+      "transitionstart",
+      event => {
+        if (
+          event.propertyName == "opacity" &&
+          event.target == gHistorySwipeAnimation._prevBox
+        ) {
+          resolve();
+        }
+      },
+      { once: true }
+    );
+  });
+
+  await panLeftToRightUpdate(tab.linkedBrowser, 100, 100, 100);
+  await panLeftToRightEnd(tab.linkedBrowser, 100, 100, 100);
+
+  // Make sure the gesture triggered going back to the previous page.
+  await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+  ok(gBrowser.webNavigation.canGoForward);
+
+  await Promise.any([transitionStartPromise, transitionCancelPromise]);
+
+  await TestUtils.waitForCondition(() => {
+    return (
+      gHistorySwipeAnimation._prevBox == null &&
+      gHistorySwipeAnimation._nextBox == null
+    );
+  });
+
+  // Navigate forward and check the forward navigation icon box state.
+  startLoadingPromise = BrowserTestUtils.browserStarted(
+    tab.linkedBrowser,
+    secondPage
+  );
+  stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+    tab.linkedBrowser,
+    secondPage
+  );
+
+  await panRightToLeftBegin(tab.linkedBrowser, 100, 100, 100);
+
+  ok(gHistorySwipeAnimation._nextBox != null, "should have nextbox");
+  transitionCancelPromise = new Promise(resolve => {
+    gHistorySwipeAnimation._nextBox.addEventListener(
+      "transitioncancel",
+      event => {
+        if (
+          event.propertyName == "opacity" &&
+          event.target == gHistorySwipeAnimation._nextBox
+        ) {
+          resolve();
+        }
+      }
+    );
+  });
+  transitionStartPromise = new Promise(resolve => {
+    gHistorySwipeAnimation._nextBox.addEventListener(
+      "transitionstart",
+      event => {
+        if (
+          event.propertyName == "opacity" &&
+          event.target == gHistorySwipeAnimation._nextBox
+        ) {
+          resolve();
+        }
+      }
+    );
+  });
+
+  await panRightToLeftUpdate(tab.linkedBrowser, 100, 100, 100);
+  await panRightToLeftEnd(tab.linkedBrowser, 100, 100, 100);
+
+  // Make sure the gesture triggered going forward to the next page.
+  await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+  ok(gBrowser.webNavigation.canGoBack);
+
+  await Promise.any([transitionStartPromise, transitionCancelPromise]);
+
+  await TestUtils.waitForCondition(() => {
+    return (
+      gHistorySwipeAnimation._nextBox == null &&
+      gHistorySwipeAnimation._prevBox == null
+    );
+  });
+
+  BrowserTestUtils.removeTab(tab);
+  await SpecialPowers.popPrefEnv();
+});
+
+// A simple test case on RTL.
+add_task(async () => {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      ["widget.swipe.success-velocity-contribution", 0.5],
+      ["intl.l10n.pseudo", "bidi"],
+    ],
+  });
+
+  const newWin = await BrowserTestUtils.openNewBrowserWindow();
+
+  const firstPage = "about:about";
+  const secondPage = "about:mozilla";
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    newWin.gBrowser,
+    firstPage,
+    true /* waitForLoad */
+  );
+
+  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, secondPage);
+  await BrowserTestUtils.browserLoaded(tab.linkedBrowser, false, secondPage);
+
+  // Make sure we can go back to the previous page.
+  ok(newWin.gBrowser.webNavigation.canGoBack);
+  // and we cannot go forward to the next page.
+  ok(!newWin.gBrowser.webNavigation.canGoForward);
+
+  // Make sure that our gesture support stuff has been initialized in the new
+  // browser window.
+  await TestUtils.waitForCondition(() => {
+    return newWin.gHistorySwipeAnimation.active;
+  });
+
+  // Try to navigate backward.
+  let startLoadingPromise = BrowserTestUtils.browserStarted(
+    tab.linkedBrowser,
+    firstPage
+  );
+  let stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+    tab.linkedBrowser,
+    firstPage
+  );
+  await panRightToLeft(tab.linkedBrowser, 100, 100, 1);
+  await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+  ok(newWin.gBrowser.webNavigation.canGoForward);
+
+  // Now try to navigate forward again.
+  startLoadingPromise = BrowserTestUtils.browserStarted(
+    tab.linkedBrowser,
+    secondPage
+  );
+  stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+    tab.linkedBrowser,
+    secondPage
+  );
+  await panLeftToRight(tab.linkedBrowser, 100, 100, 1);
+  await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+  ok(newWin.gBrowser.webNavigation.canGoBack);
+
+  await BrowserTestUtils.closeWindow(newWin);
+  await SpecialPowers.popPrefEnv();
+});
+
+add_task(async () => {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      ["widget.swipe.success-velocity-contribution", 0.5],
+      ["apz.overscroll.enabled", true],
+      ["apz.test.logging_enabled", true],
+    ],
+  });
+
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:about",
+    true /* waitForLoad */
+  );
+
+  const URL_ROOT = getRootDirectory(gTestPath).replace(
+    "chrome://mochitests/content/",
+    "http://mochi.test:8888/"
+  );
+  BrowserTestUtils.startLoadingURIString(
+    tab.linkedBrowser,
+    URL_ROOT + "helper_swipe_gesture.html"
+  );
+  await BrowserTestUtils.browserLoaded(
+    tab.linkedBrowser,
+    false /* includeSubFrames */,
+    URL_ROOT + "helper_swipe_gesture.html"
+  );
+
+  // Make sure we can go back to the previous page.
+  ok(gBrowser.webNavigation.canGoBack);
+
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async () => {
+    // Set `overscroll-behavior-x: contain` and flush it.
+    content.document.documentElement.style.overscrollBehaviorX = "contain";
+    content.document.documentElement.getBoundingClientRect();
+    await content.wrappedJSObject.promiseApzFlushedRepaints();
+  });
+
+  // Start a pan gesture but keep touching.
+  await panLeftToRightBegin(tab.linkedBrowser, 100, 100, 2);
+
+  // Flush APZ pending requests to make sure the pan gesture has been processed.
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async () => {
+    await content.wrappedJSObject.promiseApzFlushedRepaints();
+  });
+
+  const isOverscrolled = await SpecialPowers.spawn(
+    tab.linkedBrowser,
+    [],
+    () => {
+      const scrollId = SpecialPowers.DOMWindowUtils.getViewId(
+        content.document.scrollingElement
+      );
+      const data = SpecialPowers.DOMWindowUtils.getCompositorAPZTestData();
+      return data.additionalData.some(entry => {
+        return (
+          entry.key == scrollId &&
+          entry.value.split(",").includes("overscrolled")
+        );
+      });
+    }
+  );
+
+  ok(isOverscrolled, "The root scroller should have overscrolled");
+
+  // Finish the pan gesture.
+  await panLeftToRightUpdate(tab.linkedBrowser, 100, 100, 2);
+  await panLeftToRightEnd(tab.linkedBrowser, 100, 100, 2);
+
+  // And wait a while to give a chance to navigate.
+  await waitForWhile();
+
+  // Make sure any navigation didn't happen.
+  is(tab.linkedBrowser.currentURI.spec, URL_ROOT + "helper_swipe_gesture.html");
+
+  BrowserTestUtils.removeTab(tab);
+  await SpecialPowers.popPrefEnv();
+});
+
+// A test case to make sure the short circuit path for swipe-to-navigations in
+// APZ works, i.e. cases where we know for sure that the target APZC for a given
+// pan-start event isn't scrollable in the pan-start event direction.
+add_task(async () => {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["apz.overscroll.enabled", true],
+    ],
+  });
+
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:about",
+    true /* waitForLoad */
+  );
+
+  const URL_ROOT = getRootDirectory(gTestPath).replace(
+    "chrome://mochitests/content/",
+    "http://mochi.test:8888/"
+  );
+  BrowserTestUtils.startLoadingURIString(
+    tab.linkedBrowser,
+    URL_ROOT + "helper_swipe_gesture.html"
+  );
+  await BrowserTestUtils.browserLoaded(
+    tab.linkedBrowser,
+    false /* includeSubFrames */,
+    URL_ROOT + "helper_swipe_gesture.html"
+  );
+
+  // Make sure the content can allow both of overscrolling and
+  // swipe-to-navigations.
+  const overscrollBehaviorX = await SpecialPowers.spawn(
+    tab.linkedBrowser,
+    [],
+    () => {
+      return content.window.getComputedStyle(content.document.documentElement)
+        .overscrollBehaviorX;
+    }
+  );
+  is(overscrollBehaviorX, "auto");
+
+  // Make sure we can go back to the previous page.
+  ok(gBrowser.webNavigation.canGoBack);
+
+  // Start a pan gesture but keep touching.
+  await panLeftToRightBegin(tab.linkedBrowser, 100, 100, 2);
+
+  // The above pan event should invoke a SwipeGestureStart event immediately so
+  // that the swipe-to-navigation icon box should be uncollapsed to show it.
+  ok(!gHistorySwipeAnimation._prevBox.collapsed);
+
+  // Finish the pan gesture, i.e. sending a pan-end event, otherwise a new
+  // pan-start event in the next will also generate a pan-interrupt event which
+  // will break the test.
+  await panLeftToRightUpdate(tab.linkedBrowser, 100, 100, 2);
+  await panLeftToRightEnd(tab.linkedBrowser, 100, 100, 2);
+
+  BrowserTestUtils.removeTab(tab);
+  await SpecialPowers.popPrefEnv();
+});
+
+add_task(async () => {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      ["widget.swipe.success-velocity-contribution", 0.5],
+      ["apz.overscroll.enabled", true],
+      ["apz.test.logging_enabled", true],
+    ],
+  });
+
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:about",
+    true /* waitForLoad */
+  );
+
+  const URL_ROOT = getRootDirectory(gTestPath).replace(
+    "chrome://mochitests/content/",
+    "http://mochi.test:8888/"
+  );
+  BrowserTestUtils.startLoadingURIString(
+    tab.linkedBrowser,
+    URL_ROOT + "helper_swipe_gesture.html"
+  );
+  await BrowserTestUtils.browserLoaded(
+    tab.linkedBrowser,
+    false /* includeSubFrames */,
+    URL_ROOT + "helper_swipe_gesture.html"
+  );
+
+  // Make sure we can go back to the previous page.
+  ok(gBrowser.webNavigation.canGoBack);
+
+  // Start a pan gesture but keep touching.
+  await panLeftToRightBegin(tab.linkedBrowser, 100, 100, 2);
+
+  // Flush APZ pending requests to make sure the pan gesture has been processed.
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async () => {
+    await content.wrappedJSObject.promiseApzFlushedRepaints();
+  });
+
+  const isOverscrolled = await SpecialPowers.spawn(
+    tab.linkedBrowser,
+    [],
+    () => {
+      const scrollId = SpecialPowers.DOMWindowUtils.getViewId(
+        content.document.scrollingElement
+      );
+      const data = SpecialPowers.DOMWindowUtils.getCompositorAPZTestData();
+      return data.additionalData.some(entry => {
+        return entry.key == scrollId && entry.value.includes("overscrolled");
+      });
+    }
+  );
+
+  ok(!isOverscrolled, "The root scroller should not have overscrolled");
+
+  await panLeftToRightEnd(tab.linkedBrowser, 100, 100, 0);
+
+  BrowserTestUtils.removeTab(tab);
+  await SpecialPowers.popPrefEnv();
+});
+
+add_task(async () => {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      ["widget.swipe.success-velocity-contribution", 0.5],
+    ],
+  });
+
+  // Load three pages and go to the second page so that it can be navigated
+  // to both back and forward.
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:about",
+    true /* waitForLoad */
+  );
+
+  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, "about:mozilla");
+  await BrowserTestUtils.browserLoaded(
+    tab.linkedBrowser,
+    false /* includeSubFrames */,
+    "about:mozilla"
+  );
+
+  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, "about:home");
+  await BrowserTestUtils.browserLoaded(
+    tab.linkedBrowser,
+    false /* includeSubFrames */,
+    "about:home"
+  );
+
+  gBrowser.goBack();
+  await BrowserTestUtils.browserLoaded(
+    tab.linkedBrowser,
+    false /* includeSubFrames */,
+    "about:mozilla"
+  );
+
+  // Make sure we can go back and go forward.
+  ok(gBrowser.webNavigation.canGoBack);
+  ok(gBrowser.webNavigation.canGoForward);
+
+  // Start a history back pan gesture but keep touching.
+  await panLeftToRightBegin(tab.linkedBrowser, 100, 100, 1);
+
+  ok(
+    !gHistorySwipeAnimation._prevBox.collapsed,
+    "The icon box for the previous navigation should NOT be collapsed"
+  );
+  ok(
+    gHistorySwipeAnimation._nextBox.collapsed,
+    "The icon box for the next navigation should be collapsed"
+  );
+
+  // Pan back to the opposite direction so that the gesture should be cancelled.
+  // eslint-disable-next-line no-undef
+  await NativePanHandler.promiseNativePanEvent(
+    tab.linkedBrowser,
+    100,
+    100,
+    // eslint-disable-next-line no-undef
+    NativePanHandler.delta,
+    0,
+    // eslint-disable-next-line no-undef
+    NativePanHandler.updatePhase
+  );
+
+  ok(
+    gHistorySwipeAnimation._prevBox.collapsed,
+    "The icon box for the previous navigation should be collapsed"
+  );
+  ok(
+    gHistorySwipeAnimation._nextBox.collapsed,
+    "The icon box for the next navigation should be collapsed"
+  );
+
+  await panLeftToRightEnd(tab.linkedBrowser, 100, 100, 0);
+
+  BrowserTestUtils.removeTab(tab);
+  await SpecialPowers.popPrefEnv();
+});
+
+add_task(async () => {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      ["widget.swipe.success-velocity-contribution", 0.5],
+      ["apz.overscroll.enabled", true],
+      ["apz.overscroll.damping", 5.0],
+      ["apz.content_response_timeout", 0],
+    ],
+  });
+
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:about",
+    true /* waitForLoad */
+  );
+
+  const URL_ROOT = getRootDirectory(gTestPath).replace(
+    "chrome://mochitests/content/",
+    "http://mochi.test:8888/"
+  );
+
+  // Load a horizontal scrollable content.
+  BrowserTestUtils.startLoadingURIString(
+    tab.linkedBrowser,
+    URL_ROOT + "helper_swipe_gesture.html"
+  );
+  await BrowserTestUtils.browserLoaded(
+    tab.linkedBrowser,
+    false /* includeSubFrames */,
+    URL_ROOT + "helper_swipe_gesture.html"
+  );
+
+  // Make sure we can go back to the previous page.
+  ok(gBrowser.webNavigation.canGoBack);
+
+  // Shift the horizontal scroll position slightly to make the content
+  // overscrollable.
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async () => {
+    content.document.documentElement.scrollLeft = 1;
+    content.document.documentElement.getBoundingClientRect();
+    await content.wrappedJSObject.promiseApzFlushedRepaints();
+  });
+
+  // Swipe horizontally to overscroll.
+  await panLeftToRight(tab.linkedBrowser, 1, 100, 1);
+
+  // Swipe again over the overscroll gutter.
+  await panLeftToRight(tab.linkedBrowser, 1, 100, 1);
+
+  // Wait the overscroll gutter is restored.
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async () => {
+    // For some reasons using functions in apz_test_native_event_utils.js
+    // sometimes causes "TypeError content.wrappedJSObject.XXXX is not a
+    // function" error, so we observe "APZ:TransformEnd" instead of using
+    // promiseTransformEnd().
+    await new Promise((resolve, reject) => {
+      SpecialPowers.Services.obs.addObserver(function observer(
+        subject,
+        topic,
+        data
+      ) {
+        try {
+          SpecialPowers.Services.obs.removeObserver(observer, topic);
+          resolve([subject, data]);
+        } catch (ex) {
+          SpecialPowers.Services.obs.removeObserver(observer, topic);
+          reject(ex);
+        }
+      },
+      "APZ:TransformEnd");
+    });
+  });
+
+  // Set up an APZ aware event listener and...
+  await SpecialPowers.spawn(tab.linkedBrowser, [], async () => {
+    content.document.documentElement.addEventListener("wheel", e => {}, {
+      passive: false,
+    });
+    await content.wrappedJSObject.promiseApzFlushedRepaints();
+  });
+
+  // Try to swipe back again without overscrolling to make sure swipe-navigation
+  // works with the APZ aware event listener.
+  await panLeftToRight(tab.linkedBrowser, 100, 100, 1);
+
+  let startLoadingPromise = BrowserTestUtils.browserStarted(
+    tab.linkedBrowser,
+    "about:about"
+  );
+  let stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+    tab.linkedBrowser,
+    "about:about"
+  );
+
+  await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+  ok(gBrowser.webNavigation.canGoForward);
+
+  BrowserTestUtils.removeTab(tab);
+  await SpecialPowers.popPrefEnv();
+});
+
+// NOTE: This test listens wheel events so that it causes an overscroll issue
+// (bug 1800022). To avoid the bug, we need to run this test case at the end
+// of this file.
+add_task(async () => {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.gesture.swipe.left", "Browser:BackOrBackDuplicate"],
+      ["browser.gesture.swipe.right", "Browser:ForwardOrForwardDuplicate"],
+      ["widget.disable-swipe-tracker", false],
+      ["widget.swipe.velocity-twitch-tolerance", 0.0000001],
+      ["widget.swipe.success-velocity-contribution", 0.5],
+    ],
+  });
+
+  const firstPage = "about:about";
+  const secondPage = "about:mozilla";
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    firstPage,
+    true /* waitForLoad */
+  );
+
+  BrowserTestUtils.startLoadingURIString(tab.linkedBrowser, secondPage);
+  await BrowserTestUtils.browserLoaded(tab.linkedBrowser, false, secondPage);
+
+  // Make sure we can go back to the previous page.
+  ok(gBrowser.webNavigation.canGoBack);
+  // and we cannot go forward to the next page.
+  ok(!gBrowser.webNavigation.canGoForward);
+
+  let wheelEventCount = 0;
+  tab.linkedBrowser.addEventListener("wheel", () => {
+    wheelEventCount++;
+  });
+
+  // Try to navigate forward.
+  await panRightToLeft(tab.linkedBrowser, 100, 100, 1);
+  // NOTE: The last endPhase shouldn't fire a wheel event since
+  // its delta is zero.
+  is(wheelEventCount, 2, "Received 2 wheel events");
+
+  await waitForWhile();
+  // Make sure any navigation didn't happen.
+  is(tab.linkedBrowser.currentURI.spec, secondPage);
+
+  // Try to navigate backward.
+  wheelEventCount = 0;
+  let startLoadingPromise = BrowserTestUtils.browserStarted(
+    tab.linkedBrowser,
+    firstPage
+  );
+  let stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+    tab.linkedBrowser,
+    firstPage
+  );
+  await panLeftToRight(tab.linkedBrowser, 100, 100, 1);
+  // NOTE: We only get a wheel event for the beginPhase, rest of events have
+  // been captured by the swipe gesture module.
+  is(wheelEventCount, 1, "Received a wheel event");
+
+  // Make sure the gesture triggered going back to the previous page.
+  await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+  ok(gBrowser.webNavigation.canGoForward);
+
+  // Now try to navigate forward again.
+  wheelEventCount = 0;
+  startLoadingPromise = BrowserTestUtils.browserStarted(
+    tab.linkedBrowser,
+    secondPage
+  );
+  stoppedLoadingPromise = BrowserTestUtils.browserStopped(
+    tab.linkedBrowser,
+    secondPage
+  );
+  await panRightToLeft(tab.linkedBrowser, 100, 100, 1);
+  is(wheelEventCount, 1, "Received a wheel event");
+
+  await Promise.all([startLoadingPromise, stoppedLoadingPromise]);
+
+  ok(gBrowser.webNavigation.canGoBack);
+
+  // Now try to navigate backward again but with preventDefault-ed event
+  // handler.
+  wheelEventCount = 0;
+  let wheelEventListener = event => {
+    event.preventDefault();
+  };
+  tab.linkedBrowser.addEventListener("wheel", wheelEventListener);
+  await panLeftToRight(tab.linkedBrowser, 100, 100, 1);
+  is(wheelEventCount, 3, "Received all wheel events");
+
+  await waitForWhile();
+  // Make sure any navigation didn't happen.
+  is(tab.linkedBrowser.currentURI.spec, secondPage);
+
+  // Now drop the event handler and disable the swipe tracker and try to swipe
+  // again.
+  wheelEventCount = 0;
+  tab.linkedBrowser.removeEventListener("wheel", wheelEventListener);
+  await SpecialPowers.pushPrefEnv({
+    set: [["widget.disable-swipe-tracker", true]],
+  });
+
+  await panLeftToRight(tab.linkedBrowser, 100, 100, 1);
+  is(wheelEventCount, 3, "Received all wheel events");
+
+  await waitForWhile();
+  // Make sure any navigation didn't happen.
+  is(tab.linkedBrowser.currentURI.spec, secondPage);
+
+  BrowserTestUtils.removeTab(tab);
+  await SpecialPowers.popPrefEnv();
+});
diff --git a/widget/tests/browser/file_ime_state_tests.html b/widget/tests/browser/file_ime_state_tests.html
new file mode 100644
index 0000000000..d6b63f1e52
--- /dev/null
+++ b/widget/tests/browser/file_ime_state_tests.html
@@ -0,0 +1,48 @@
+<!doctype html>
+<html style="ime-mode: disabled;">
+<head>
+<meta charset="utf-8">
+<script src="file_ime_state_test_helper.js"></script>
+<script src="file_test_ime_state_in_contenteditable_on_readonly_change.js"></script>
+<script src="file_test_ime_state_in_text_control_on_reframe.js"></script>
+<script src="file_test_ime_state_on_focus_move.js"></script>
+<script src="file_test_ime_state_on_input_type_change.js"></script>
+<script src="file_test_ime_state_on_readonly_change.js"></script>
+<script>
+"use strict";
+
+/* import-globals-from ../file_ime_state_test_helper.js */
+/* import-globals-from ../file_test_ime_state_in_contenteditable_on_readonly_change.js */
+/* import-globals-from ../file_test_ime_state_in_text_control_on_reframe.js */
+/* import-globals-from ../file_test_ime_state_on_focus_move.js */
+/* import-globals-from ../file_test_ime_state_on_input_type_change.js */
+/* import-globals-from ../file_test_ime_state_on_readonly_change.js */
+
+function createIMEStateInContentEditableOnReadonlyChangeTester() {
+  return new IMEStateInContentEditableOnReadonlyChangeTester();
+}
+function createIMEStateOfTextControlInContentEditableOnReadonlyChangeTester() {
+  return new IMEStateOfTextControlInContentEditableOnReadonlyChangeTester();
+}
+function createIMEStateOutsideContentEditableOnReadonlyChangeTester() {
+  return new IMEStateOutsideContentEditableOnReadonlyChangeTester();
+}
+function createIMEStateInTextControlOnReframeTester() {
+  return new IMEStateInTextControlOnReframeTester();
+}
+function createIMEStateWhenNoActiveElementTester(aDescription) {
+  return new IMEStateWhenNoActiveElementTester(aDescription);
+}
+function createIMEStateOnFocusMoveTester(aDescription, aIndex, aWindow = window) {
+  return new IMEStateOnFocusMoveTester(aDescription, aIndex, aWindow);
+}
+function createIMEStateOnInputTypeChangeTester(aSrcIndex) {
+  return new IMEStateOnInputTypeChangeTester(aSrcIndex);
+}
+function createIMEStateOnReadonlyChangeTester() {
+  return new IMEStateOnReadonlyChangeTester();
+}
+</script>
+</head>
+<body style="ime-mode: disabled;"><div style="ime-mode: disabled;"></div></body>
+</html>
diff --git a/widget/tests/browser/helper_scrollbar_colors.html b/widget/tests/browser/helper_scrollbar_colors.html
new file mode 100644
index 0000000000..e6001906e2
--- /dev/null
+++ b/widget/tests/browser/helper_scrollbar_colors.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html>
+<meta charset="UTF-8">
+<title>Test for scrollbar-*-color properties</title>
+<style>
+  .outer {
+    width: 100px;
+    height: 100px;
+    background: yellow;
+    overflow: scroll;
+  }
+  .inner {
+    width: 200px;
+    height: 200px;
+  }
+</style>
+<style id="style"></style>
+<div class="outer">
+  <div class="inner">
+  </div>
+</div>
+</html>
diff --git a/widget/tests/browser/helper_swipe_gesture.html b/widget/tests/browser/helper_swipe_gesture.html
new file mode 100644
index 0000000000..1fa79dbbf3
--- /dev/null
+++ b/widget/tests/browser/helper_swipe_gesture.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html>
+<script src="/tests/SimpleTest/paint_listener.js"></script>
+<script src="/browser/gfx/layers/apz/test/mochitest/apz_test_utils.js"></script>
+<script src="/browser/gfx/layers/apz/test/mochitest/apz_test_native_event_utils.js"></script>
+<style>
+html {
+  overflow-x: scroll;
+}
+body {
+  margin: 0;
+}
+div {
+  height: 100vh;
+  width: 110vw;
+  background-color: blue;
+}
+</style>
+<div></div>
+</html>
diff --git a/widget/tests/bug586713_window.xhtml b/widget/tests/bug586713_window.xhtml
new file mode 100644
index 0000000000..c180c00235
--- /dev/null
+++ b/widget/tests/bug586713_window.xhtml
@@ -0,0 +1,50 @@
+<?xml version="1.0"?>
+
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+
+<window id="bug586713_window"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        width="300"
+        height="300"
+        onload="onLoad();"
+        title="Bug 586713 Test">
+
+  <menubar id="nativemenubar">
+    <menu id="foo" label="Foo">
+      <menupopup>
+        <menuitem label="FooItem0"/>
+      </menupopup>
+    </menu>
+  </menubar>
+
+  <script type="application/javascript"><![CDATA[
+    function ok(condition, message) {
+      window.arguments[0].SimpleTest.ok(condition, message);
+    }
+
+    function onTestsFinished() {
+      window.close();
+      window.arguments[0].SimpleTest.finish();
+    }
+
+    var fooCallCount = 0;
+    function foo() {
+      fooCallCount++;
+      let instruction = document.createProcessingInstruction("xml-stylesheet", 'href="chrome://foo.css" type="text/css"');
+      document.insertBefore(instruction, document.documentElement);
+      if (fooCallCount == 2) {
+        ok(true, "If we got here we didn't crash, excellent.");
+        onTestsFinished();
+      }
+    }
+
+    function onLoad() {
+      foo();
+      setTimeout(() => foo(), 0);
+    }
+  ]]></script>
+</window>
diff --git a/widget/tests/chrome.toml b/widget/tests/chrome.toml
new file mode 100644
index 0000000000..08d02d3c36
--- /dev/null
+++ b/widget/tests/chrome.toml
@@ -0,0 +1,200 @@
+[DEFAULT]
+skip-if = ["os == 'android'"]
+support-files = [
+  "empty_window.xhtml",
+  "clipboard_helper.js",
+]
+
+["test_alwaysontop_focus.xhtml"]
+
+# Privacy relevant
+
+["test_bug1123480.xhtml"]
+skip-if = ["win11_2009 && bits == 32"]
+
+["test_bug343416.xhtml"]
+skip-if = ["debug"]
+
+["test_bug428405.xhtml"]
+run-if = ["os == 'mac'"] # Cocoa widget test
+
+["test_bug429954.xhtml"]
+support-files = ["window_bug429954.xhtml"]
+
+["test_bug444800.xhtml"]
+
+["test_bug466599.xhtml"]
+run-if = ["os == 'mac'"] # Cocoa widget test
+
+["test_bug478536.xhtml"]
+skip-if = ["true"] # Bug 561929
+support-files = ["window_bug478536.xhtml"]
+
+["test_bug485118.xhtml"]
+run-if = ["os == 'mac'"] # Cocoa widget test
+
+["test_bug517396.xhtml"]
+skip-if = ["verify && os == 'win'"]
+
+["test_bug522217.xhtml"]
+tags = "fullscreen"
+run-if = ["os == 'mac'"] # Cocoa widget test
+support-files = ["window_bug522217.xhtml"]
+
+["test_bug538242.xhtml"]
+support-files = ["window_bug538242.xhtml"]
+
+["test_bug565392.html"]
+run-if = ["os == 'win'"]
+
+["test_bug586713.xhtml"]
+run-if = ["os == 'mac'"] # Cocoa widget test
+support-files = ["bug586713_window.xhtml"]
+
+["test_bug593307.xhtml"]
+support-files = [
+  "window_bug593307_offscreen.xhtml",
+  "window_bug593307_centerscreen.xhtml",
+]
+
+["test_bug596600.xhtml"]
+support-files = "file_bug596600.html"
+run-if = ["os == 'mac'"] # Cocoa widget test
+
+["test_bug673301.xhtml"]
+run-if = ["os == 'mac'"] # Cocoa widget test
+
+["test_bug760802.xhtml"]
+
+["test_clipboard_chrome.html"]
+support-files = "file_test_clipboard.js"
+
+["test_clipboard_asyncGetData_chrome.html"]
+support-files = "file_test_clipboard_asyncGetData.js"
+
+["test_clipboard_asyncSetData_chrome.html"]
+support-files = "file_test_clipboard_asyncSetData.js"
+
+["test_clipboard_cache_chrome.html"]
+
+["test_clipboard_owner_chrome.html"]
+
+["test_composition_text_querycontent.xhtml"]
+support-files = ["window_composition_text_querycontent.xhtml"]
+
+["test_ime_state_in_contenteditable_on_readonly_change_in_parent.html"]
+support-files = [
+  "file_ime_state_test_helper.js",
+  "file_test_ime_state_in_contenteditable_on_readonly_change.js",
+]
+
+["test_ime_state_in_plugin_in_parent.html"]
+support-files = ["file_ime_state_test_helper.js"]
+
+["test_ime_state_in_text_control_on_reframe_in_parent.html"]
+support-files = [
+  "file_ime_state_test_helper.js",
+  "file_test_ime_state_in_text_control_on_reframe.js",
+]
+
+["test_ime_state_on_editable_state_change_in_parent.html"]
+support-files = ["file_ime_state_test_helper.js"]
+
+["test_ime_state_on_focus_move_in_parent.html"]
+support-files = [
+  "file_ime_state_test_helper.js",
+  "file_test_ime_state_on_focus_move.js",
+]
+
+["test_ime_state_on_input_type_change_in_parent.html"]
+skip-if = ["true"] # Bug 1817704
+support-files = [
+  "file_ime_state_test_helper.js",
+  "file_test_ime_state_on_input_type_change.js",
+]
+
+["test_ime_state_on_readonly_change_in_parent.html"]
+support-files = [
+  "file_ime_state_test_helper.js",
+  "file_test_ime_state_on_readonly_change.js",
+]
+
+["test_ime_state_others_in_parent.html"]
+support-files = ["window_imestate_iframes.html"]
+
+["test_input_events_on_deactive_window.xhtml"]
+support-files = ["file_input_events_on_deactive_window.html"]
+
+["test_key_event_counts.xhtml"]
+run-if = ["os == 'mac'"] # Cocoa widget test
+
+["test_keycodes.xhtml"]
+
+["test_mouse_scroll.xhtml"]
+run-if = ["os == 'win'"] # windows widget test
+support-files = [
+  "window_mouse_scroll_win.html",
+  "window_mouse_scroll_win_2.html",
+]
+
+["test_native_key_bindings_mac.html"]
+run-if = ["os == 'mac'"] # Cocoa widget test
+skip-if = [
+  "verify",
+]
+
+["test_native_menus.xhtml"]
+run-if = ["os == 'mac'"] # Cocoa widget test
+support-files = ["native_menus_window.xhtml"]
+
+["test_panel_mouse_coords.xhtml"]
+skip-if = ["os == 'win'"] # bug 1009955
+
+["test_platform_colors.xhtml"]
+skip-if = ["true"] # Bug 1207190
+
+["test_position_on_resize.xhtml"]
+skip-if = [
+  "verify && os == 'win'",
+  "os == 'linux' && bits == 64", # Bug 1616760
+]
+
+["test_secure_input.html"]
+run-if = ["os == 'mac'"] # Cocoa widget test
+support-files = ["file_secure_input.html"]
+
+["test_sizemode_events.xhtml"]
+
+["test_standalone_native_menu.xhtml"]
+run-if = ["os == 'mac'"] # Cocoa widget test
+support-files = ["standalone_native_menu_window.xhtml"]
+
+["test_surrogate_pair_native_key_handling.xhtml"]
+run-if = ["os == 'win'"] # Windows widget test
+
+["test_system_font_changes.xhtml"]
+support-files = ["system_font_changes.xhtml"]
+run-if = ["os == 'linux'"] # Currently the test works on only gtk3
+
+["test_system_status_bar.xhtml"]
+run-if = ["os == 'mac'"] # Cocoa widget test
+
+["test_taskbar_progress.xhtml"]
+skip-if = [
+  "os == 'linux'",
+  "os == 'android'",
+  "win10_2009 && !ccov", # Bug 1456811
+]
+
+["test_transferable_overflow.xhtml"]
+skip-if = [
+  "verify && apple_catalina",
+  "verify && os == 'linux'",
+]
+
+["test_wheeltransaction.xhtml"]
+support-files = ["window_wheeltransaction.xhtml"]
+
+# Windows
+# taskbar_previews.xhtml
+# window_state_windows.xhtml
diff --git a/widget/tests/clipboard_helper.js b/widget/tests/clipboard_helper.js
new file mode 100644
index 0000000000..96787468fb
--- /dev/null
+++ b/widget/tests/clipboard_helper.js
@@ -0,0 +1,230 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const Cc = SpecialPowers.Cc;
+const Ci = SpecialPowers.Ci;
+const Cr = SpecialPowers.Cr;
+const clipboard = SpecialPowers.Services.clipboard;
+const clipboardTypes = [
+  clipboard.kGlobalClipboard,
+  clipboard.kSelectionClipboard,
+  clipboard.kFindClipboard,
+  clipboard.kSelectionCache,
+];
+
+function emptyClipboardData(aType) {
+  // XXX gtk doesn't support emptying clipboard data which is stored from
+  // other application (bug 1853884). As a workaround, we set dummy data
+  // to the clipboard first to ensure the subsequent emptyClipboard call
+  // works.
+  if (navigator.platform.includes("Linux")) {
+    writeStringToClipboard("foo", "text/plain", aType);
+  }
+
+  clipboard.emptyClipboard(aType);
+}
+
+function cleanupAllClipboard() {
+  clipboardTypes.forEach(function (type) {
+    if (clipboard.isClipboardTypeSupported(type)) {
+      info(`cleanup clipboard ${type}`);
+      emptyClipboardData(type);
+    }
+  });
+}
+
+function generateRandomString() {
+  return "random number: " + Math.random();
+}
+
+function generateNewTransferable(aFlavor, aStr) {
+  let trans = Cc["@mozilla.org/widget/transferable;1"].createInstance(
+    Ci.nsITransferable
+  );
+  trans.init(null);
+  trans.addDataFlavor(aFlavor);
+
+  let supportsStr = Cc["@mozilla.org/supports-string;1"].createInstance(
+    Ci.nsISupportsString
+  );
+  supportsStr.data = aStr;
+  trans.setTransferData(aFlavor, supportsStr);
+
+  return trans;
+}
+
+function addStringToTransferable(aFlavor, aStr, aTrans) {
+  aTrans.addDataFlavor(aFlavor);
+
+  let supportsStr = Cc["@mozilla.org/supports-string;1"].createInstance(
+    Ci.nsISupportsString
+  );
+  supportsStr.data = aStr;
+  aTrans.setTransferData(aFlavor, supportsStr);
+}
+
+function updateStringToTransferable(aFlavor, aStr, aTrans) {
+  let supportsStr = Cc["@mozilla.org/supports-string;1"].createInstance(
+    Ci.nsISupportsString
+  );
+  supportsStr.data = aStr;
+  aTrans.setTransferData(aFlavor, supportsStr);
+}
+
+function writeStringToClipboard(
+  aStr,
+  aFlavor,
+  aClipboardType,
+  aClipboardOwner = null,
+  aAsync = false
+) {
+  let trans = Cc["@mozilla.org/widget/transferable;1"].createInstance(
+    Ci.nsITransferable
+  );
+  trans.init(null);
+  trans.addDataFlavor(aFlavor);
+
+  let supportsStr = Cc["@mozilla.org/supports-string;1"].createInstance(
+    Ci.nsISupportsString
+  );
+  supportsStr.data = aStr;
+  trans.setTransferData(aFlavor, supportsStr);
+
+  if (aAsync) {
+    let request = clipboard.asyncSetData(aClipboardType);
+    request.setData(trans, aClipboardOwner);
+    return;
+  }
+
+  clipboard.setData(trans, aClipboardOwner, aClipboardType);
+  // XXX gtk doesn't support get empty text data from clipboard, bug 1852983.
+  if (aStr == "" && navigator.platform.includes("Linux")) {
+    todo_is(
+      getClipboardData(aFlavor, aClipboardType),
+      "",
+      `Should get empty string on clipboard type ${aClipboardType}`
+    );
+  } else {
+    is(
+      getClipboardData(aFlavor, aClipboardType),
+      // On Windows, widget adds extra data into HTML clipboard.
+      aFlavor == "text/html" && navigator.platform.includes("Win")
+        ? `<html><body>\n<!--StartFragment-->${aStr}<!--EndFragment-->\n</body>\n</html>`
+        : aStr,
+      "ensure clipboard data is set"
+    );
+  }
+}
+
+function writeRandomStringToClipboard(
+  aFlavor,
+  aClipboardType,
+  aClipboardOwner = null,
+  aAsync = false
+) {
+  let randomString = generateRandomString();
+  writeStringToClipboard(
+    randomString,
+    aFlavor,
+    aClipboardType,
+    aClipboardOwner,
+    aAsync
+  );
+  return randomString;
+}
+
+function getClipboardData(aFlavor, aClipboardType) {
+  var trans = Cc["@mozilla.org/widget/transferable;1"].createInstance(
+    Ci.nsITransferable
+  );
+  trans.init(null);
+  trans.addDataFlavor(aFlavor);
+  clipboard.getData(
+    trans,
+    aClipboardType,
+    SpecialPowers.wrap(window).browsingContext.currentWindowContext
+  );
+
+  try {
+    var data = SpecialPowers.createBlankObject();
+    trans.getTransferData(aFlavor, data);
+    return data.value.QueryInterface(SpecialPowers.Ci.nsISupportsString).data;
+  } catch (ex) {
+    // If the clipboard is empty getTransferData will throw.
+    return null;
+  }
+}
+
+function asyncGetClipboardData(aClipboardType) {
+  return new Promise((resolve, reject) => {
+    try {
+      clipboard.asyncGetData(
+        ["text/plain", "text/html", "image/png"],
+        aClipboardType,
+        null,
+        SpecialPowers.Services.scriptSecurityManager.getSystemPrincipal(),
+        {
+          QueryInterface: SpecialPowers.ChromeUtils.generateQI([
+            "nsIAsyncClipboardGetCallback",
+          ]),
+          // nsIAsyncClipboardGetCallback
+          onSuccess: SpecialPowers.wrapCallback(function (
+            aAsyncGetClipboardData
+          ) {
+            resolve(aAsyncGetClipboardData);
+          }),
+          onError: SpecialPowers.wrapCallback(function (aResult) {
+            reject(aResult);
+          }),
+        }
+      );
+    } catch (e) {
+      ok(false, `asyncGetData should not throw`);
+      reject(e);
+    }
+  });
+}
+
+function asyncClipboardRequestGetData(aRequest, aFlavor, aThrows = false) {
+  return new Promise((resolve, reject) => {
+    var trans = Cc["@mozilla.org/widget/transferable;1"].createInstance(
+      Ci.nsITransferable
+    );
+    trans.init(null);
+    trans.addDataFlavor(aFlavor);
+    try {
+      aRequest.getData(trans, aResult => {
+        if (aResult != Cr.NS_OK) {
+          reject(aResult);
+          return;
+        }
+
+        try {
+          var data = SpecialPowers.createBlankObject();
+          trans.getTransferData(aFlavor, data);
+          resolve(data.value.QueryInterface(Ci.nsISupportsString).data);
+        } catch (ex) {
+          // XXX: should widget set empty string to transferable when there no
+          // data in system clipboard?
+          resolve("");
+        }
+      });
+      ok(
+        !aThrows,
+        `nsIAsyncGetClipboardData.getData should ${
+          aThrows ? "throw" : "success"
+        }`
+      );
+    } catch (e) {
+      ok(
+        aThrows,
+        `nsIAsyncGetClipboardData.getData should ${
+          aThrows ? "throw" : "success"
+        }`
+      );
+      reject(e);
+    }
+  });
+}
diff --git a/widget/tests/empty_window.xhtml b/widget/tests/empty_window.xhtml
new file mode 100644
index 0000000000..f0e01761d2
--- /dev/null
+++ b/widget/tests/empty_window.xhtml
@@ -0,0 +1,4 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="Empty window"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"/>
diff --git a/widget/tests/file_bug596600.html b/widget/tests/file_bug596600.html
new file mode 100644
index 0000000000..1b178a6b68
--- /dev/null
+++ b/widget/tests/file_bug596600.html
@@ -0,0 +1,4 @@
+<!DOCTYPE html>
+<body>
+Content page
+</body>
diff --git a/widget/tests/file_ime_state_test_helper.js b/widget/tests/file_ime_state_test_helper.js
new file mode 100644
index 0000000000..0cee5c036f
--- /dev/null
+++ b/widget/tests/file_ime_state_test_helper.js
@@ -0,0 +1,197 @@
+"use strict";
+
+function IsIMEOpenStateSupported() {
+  // We support to control IME open state on Windows and Mac actually.  However,
+  // we cannot test it on Mac if the current keyboard layout is not CJK. And also
+  // we cannot test it on Win32 if the system didn't be installed IME. So,
+  // currently we should not run the open state testing.
+  return false;
+}
+
+/**
+ * @param {Node} aNode
+ */
+function nodeIsInShadowDOM(aNode) {
+  for (let node = aNode; node; node = node.parentNode) {
+    if (node instanceof ShadowRoot) {
+      return true;
+    }
+    if (node == node.parentNode) {
+      break;
+    }
+  }
+  return false;
+}
+
+/**
+ * @param {Node} aNode
+ */
+function nodeIsInDesignMode(aNode) {
+  return (
+    aNode.isConnected &&
+    !nodeIsInShadowDOM(aNode) &&
+    aNode.ownerDocument.designMode == "on"
+  );
+}
+
+/**
+ * param {Node} aNode
+ */
+function getEditingHost(aNode) {
+  if (nodeIsInDesignMode(aNode)) {
+    return aNode.ownerDocument.documentElement;
+  }
+  for (
+    let element =
+      aNode.nodeType == Node.ELEMENT_NODE ? aNode : aNode.parentElement;
+    element;
+    element = element.parentElement
+  ) {
+    const contenteditable = element.getAttribute("contenteditable");
+    if (contenteditable === "true" || contenteditable === "") {
+      return element;
+    }
+    if (contenteditable === "false") {
+      return null;
+    }
+  }
+  return null;
+}
+
+/**
+ * @param {Node} aNode
+ */
+function nodeIsEditable(aNode) {
+  if (nodeIsInDesignMode(aNode)) {
+    return true;
+  }
+  if (!aNode.isConnected) {
+    return false;
+  }
+  return getEditingHost(aNode) != null;
+}
+
+/**
+ * @param {Element} aElement
+ */
+function elementIsEditingHost(aElement) {
+  return (
+    nodeIsEditable(aElement) &&
+    (!aElement.parentElement || !getEditingHost(aElement) == aElement)
+  );
+}
+
+/**
+ * @returns {Element} Retrieve focused element.  If focused element is a element
+ *                    in UA widget, this returns its host element.  E.g., when
+ *                    a button in the controls of <audio> or <video> has focus,
+ *                    this returns the <video> or <audio>.
+ */
+function getFocusedElementOrUAWidgetHost() {
+  const focusedElement = SpecialPowers.focusManager.focusedElement;
+  if (SpecialPowers.wrap(focusedElement)?.containingShadowRoot?.isUAWidget()) {
+    return focusedElement.containingShadowRoot.host;
+  }
+  return focusedElement;
+}
+
+class TIPWrapper {
+  #mTIP = null;
+  #mFocusBlurNotifications = [];
+  #mFocusBlurListener;
+  #mWindow;
+
+  constructor(aWindow) {
+    this.#mWindow = aWindow;
+    this.#mTIP = Cc["@mozilla.org/text-input-processor;1"].createInstance(
+      Ci.nsITextInputProcessor
+    );
+    if (!this.beginInputTransactionForTests()) {
+      this.#mTIP = null;
+    }
+  }
+
+  beginInputTransactionForTests() {
+    return this.#mTIP.beginInputTransactionForTests(
+      this.#mWindow,
+      this.#observer.bind(this)
+    );
+  }
+
+  typeA() {
+    const AKey = new this.#mWindow.KeyboardEvent("", {
+      key: "a",
+      code: "KeyA",
+      keyCode: this.#mWindow.KeyboardEvent.DOM_VK_A,
+    });
+    this.#mTIP.keydown(AKey);
+    this.#mTIP.keyup(AKey);
+  }
+
+  isAvailable() {
+    return this.#mTIP != null;
+  }
+
+  #observer(aTIP, aNotification) {
+    if (aTIP != this.#mTIP) {
+      return false;
+    }
+    switch (aNotification.type) {
+      case "request-to-commit":
+        this.#mTIP.commitComposition();
+        break;
+      case "request-to-cancel":
+        this.#mTIP.cancelComposition();
+        break;
+      case "notify-focus":
+      case "notify-blur":
+        this.#mFocusBlurNotifications.push(aNotification.type);
+        if (this.#mFocusBlurListener) {
+          this.#mFocusBlurListener(aNotification.type);
+        }
+        break;
+    }
+    return true;
+  }
+
+  get TIP() {
+    return this.#mTIP;
+  }
+
+  /**
+   * @param {Function} aListener
+   */
+  set onIMEFocusBlur(aListener) {
+    this.#mFocusBlurListener = aListener;
+  }
+
+  get focusBlurNotifications() {
+    return this.#mFocusBlurNotifications.concat();
+  }
+
+  get numberOfFocusNotifications() {
+    return this.#mFocusBlurNotifications.filter(t => t == "notify-focus")
+      .length;
+  }
+  get numberOfBlurNotifications() {
+    return this.#mFocusBlurNotifications.filter(t => t == "notify-blur").length;
+  }
+
+  get IMEHasFocus() {
+    return (
+      !!this.#mFocusBlurNotifications.length &&
+      this.#mFocusBlurNotifications[this.#mFocusBlurNotifications.length - 1] ==
+        "notify-focus"
+    );
+  }
+
+  clearFocusBlurNotifications() {
+    this.#mFocusBlurNotifications = [];
+  }
+
+  destroy() {
+    this.#mTIP = null;
+    this.#mFocusBlurListener = null;
+    this.#mFocusBlurNotifications = [];
+  }
+}
diff --git a/widget/tests/file_input_events_on_deactive_window.html b/widget/tests/file_input_events_on_deactive_window.html
new file mode 100644
index 0000000000..e733adbb9d
--- /dev/null
+++ b/widget/tests/file_input_events_on_deactive_window.html
@@ -0,0 +1,5 @@
+<html>
+<body>
+  this is an active window.
+</body>
+</html>
diff --git a/widget/tests/file_secure_input.html b/widget/tests/file_secure_input.html
new file mode 100644
index 0000000000..28fec7b44b
--- /dev/null
+++ b/widget/tests/file_secure_input.html
@@ -0,0 +1 @@
+<input id="text" type"text"><input id="password" type"password">
diff --git a/widget/tests/file_test_clipboard.js b/widget/tests/file_test_clipboard.js
new file mode 100644
index 0000000000..76bdbaa84d
--- /dev/null
+++ b/widget/tests/file_test_clipboard.js
@@ -0,0 +1,153 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* import-globals-from clipboard_helper.js */
+
+"use strict";
+
+function getLoadContext() {
+  return SpecialPowers.wrap(window).docShell.QueryInterface(Ci.nsILoadContext);
+}
+
+// Get clipboard data to paste.
+function paste(clipboard) {
+  let trans = Cc["@mozilla.org/widget/transferable;1"].createInstance(
+    Ci.nsITransferable
+  );
+  trans.init(getLoadContext());
+  trans.addDataFlavor("text/plain");
+  clipboard.getData(
+    trans,
+    Ci.nsIClipboard.kGlobalClipboard,
+    SpecialPowers.wrap(window).browsingContext.currentWindowContext
+  );
+  let str = SpecialPowers.createBlankObject();
+  try {
+    trans.getTransferData("text/plain", str);
+  } catch (e) {
+    str = "";
+  }
+  if (str) {
+    str = str.value.QueryInterface(Ci.nsISupportsString);
+    if (str) {
+      str = str.data;
+    }
+  }
+  return str;
+}
+
+add_setup(function init() {
+  cleanupAllClipboard();
+});
+
+/* Test for bug 948065 */
+add_task(function test_copy() {
+  // Test copy.
+  const data = "random number: " + Math.random();
+  let helper = Cc["@mozilla.org/widget/clipboardhelper;1"].getService(
+    Ci.nsIClipboardHelper
+  );
+  helper.copyString(data);
+  is(paste(clipboard), data, "Data was successfully copied.");
+
+  clipboard.emptyClipboard(Ci.nsIClipboard.kGlobalClipboard);
+  is(paste(clipboard), "", "Data was successfully cleared.");
+
+  cleanupAllClipboard();
+});
+
+/* Tests for bug 1834073 */
+clipboardTypes.forEach(function (clipboardType) {
+  if (clipboard.isClipboardTypeSupported(clipboardType)) {
+    add_task(function test_clipboard_apis() {
+      info(`Test clipboard apis for type ${clipboardType}`);
+
+      // Set clipboard data
+      let str;
+      try {
+        str = writeRandomStringToClipboard("text/plain", clipboardType);
+      } catch (e) {
+        ok(
+          false,
+          `setData should not throw error for clipboard type ${clipboardType}`
+        );
+      }
+
+      // Test hasDataMatchingFlavors
+      try {
+        ok(
+          clipboard.hasDataMatchingFlavors(["text/plain"], clipboardType),
+          `Test hasDataMatchingFlavors for clipboard type ${clipboardType}`
+        );
+      } catch (e) {
+        ok(
+          false,
+          `hasDataMatchingFlavors should not throw error for clipboard type ${clipboardType}`
+        );
+      }
+
+      // Test getData
+      try {
+        is(
+          getClipboardData("text/plain", clipboardType),
+          str,
+          `Test getData for clipboard type ${clipboardType}`
+        );
+      } catch (e) {
+        ok(
+          false,
+          `getData should not throw error for clipboard type ${clipboardType}`
+        );
+      }
+    });
+
+    add_task(function test_clipboard_set_empty_string() {
+      info(`Test setting empty string to type ${clipboardType}`);
+
+      // Clear clipboard type.
+      clipboard.emptyClipboard(clipboardType);
+      is(
+        getClipboardData("text/plain", clipboardType),
+        null,
+        `Should get null data on clipboard type ${clipboardType}`
+      );
+      ok(
+        !clipboard.hasDataMatchingFlavors(["text/plain"], clipboardType),
+        `Should not have text/plain flavor on clipboard ${clipboardType}`
+      );
+
+      // Set text/plain to empty string.
+      writeStringToClipboard("", "text/plain", clipboardType);
+      // XXX gtk doesn't support get empty text data from clipboard, bug 1852983.
+      if (navigator.platform.includes("Linux")) {
+        todo_is(
+          getClipboardData("text/plain", clipboardType),
+          "",
+          `Should get empty string on clipboard type ${clipboardType}`
+        );
+      } else {
+        is(
+          getClipboardData("text/plain", clipboardType),
+          "",
+          `Should get empty string on clipboard type ${clipboardType}`
+        );
+      }
+      // XXX android doesn't support setting empty text data to clipboard, bug 1841058.
+      if (navigator.userAgent.includes("Android")) {
+        todo_is(
+          clipboard.hasDataMatchingFlavors(["text/plain"], clipboardType),
+          true,
+          `Should have text/plain flavor on clipboard ${clipboardType}`
+        );
+      } else {
+        ok(
+          clipboard.hasDataMatchingFlavors(["text/plain"], clipboardType),
+          `Should have text/plain flavor on clipboard ${clipboardType}`
+        );
+      }
+
+      // Clear all clipboard data.
+      cleanupAllClipboard();
+    });
+  }
+});
diff --git a/widget/tests/file_test_clipboard_asyncGetData.js b/widget/tests/file_test_clipboard_asyncGetData.js
new file mode 100644
index 0000000000..e7f2e5f0f1
--- /dev/null
+++ b/widget/tests/file_test_clipboard_asyncGetData.js
@@ -0,0 +1,170 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* import-globals-from clipboard_helper.js */
+
+"use strict";
+
+clipboardTypes.forEach(function (type) {
+  if (!clipboard.isClipboardTypeSupported(type)) {
+    add_task(async function test_clipboard_asyncGetData_not_support() {
+      info(`Test asyncGetData request throwing on ${type}`);
+      SimpleTest.doesThrow(
+        () => clipboard.asyncGetData(["text/plain"], type, {}),
+        "Passing unsupported clipboard type should throw"
+      );
+    });
+    return;
+  }
+
+  add_task(async function test_clipboard_asyncGetData_throw() {
+    info(`Test asyncGetData request throwing on ${type}`);
+    SimpleTest.doesThrow(
+      () => clipboard.asyncGetData([], type, {}),
+      "Passing empty flavor list should throw"
+    );
+
+    SimpleTest.doesThrow(
+      () => clipboard.asyncGetData(["text/plain"], type, null),
+      "Passing no callback should throw"
+    );
+  });
+
+  add_task(async function test_clipboard_asyncGetData_no_matched_flavor() {
+    info(`Test asyncGetData have no matched flavor on ${type}`);
+    cleanupAllClipboard();
+    is(getClipboardData("text/plain", type), null, "ensure clipboard is empty");
+
+    writeRandomStringToClipboard("text/plain", type);
+    let request = await new Promise(resolve => {
+      clipboard.asyncGetData(
+        ["text/html"],
+        type,
+        null,
+        SpecialPowers.Services.scriptSecurityManager.getSystemPrincipal(),
+        {
+          QueryInterface: SpecialPowers.ChromeUtils.generateQI([
+            "nsIAsyncClipboardGetCallback",
+          ]),
+          // nsIAsyncClipboardGetCallback
+          onSuccess: SpecialPowers.wrapCallback(function (
+            aAsyncGetClipboardData
+          ) {
+            resolve(aAsyncGetClipboardData);
+          }),
+        }
+      );
+    });
+    isDeeply(request.flavorList, [], "Check flavorList");
+  });
+
+  add_task(async function test_empty_data() {
+    info(`Test asyncGetData request with empty data on ${type}`);
+    cleanupAllClipboard();
+    is(getClipboardData("text/plain", type), null, "ensure clipboard is empty");
+
+    let request = await asyncGetClipboardData(type);
+    isDeeply(request.flavorList, [], "Check flavorList");
+    await asyncClipboardRequestGetData(request, "text/plain", true).catch(
+      () => {}
+    );
+  });
+
+  add_task(async function test_clipboard_asyncGetData_after_write() {
+    info(`Test asyncGetData request after write on ${type}`);
+
+    let str = writeRandomStringToClipboard("text/plain", type);
+    let request = await asyncGetClipboardData(type);
+    isDeeply(request.flavorList, ["text/plain"], "Check flavorList");
+    is(
+      await asyncClipboardRequestGetData(request, "text/plain"),
+      str,
+      "Check data"
+    );
+    ok(request.valid, "request should still be valid");
+    // Requesting a flavor that is not in the list should throw error.
+    await asyncClipboardRequestGetData(request, "text/html", true).catch(
+      () => {}
+    );
+    ok(request.valid, "request should still be valid");
+
+    // Writing a new data should invalid existing get request.
+    str = writeRandomStringToClipboard("text/plain", type);
+    await asyncClipboardRequestGetData(request, "text/plain").then(
+      () => {
+        ok(false, "asyncClipboardRequestGetData should not success");
+      },
+      e => {
+        ok(true, "asyncClipboardRequestGetData should reject");
+      }
+    );
+    ok(!request.valid, "request should no longer be valid");
+
+    info(`check clipboard data again`);
+    request = await asyncGetClipboardData(type);
+    isDeeply(request.flavorList, ["text/plain"], "Check flavorList");
+    is(
+      await asyncClipboardRequestGetData(request, "text/plain"),
+      str,
+      "Check data"
+    );
+
+    cleanupAllClipboard();
+  });
+
+  add_task(async function test_clipboard_asyncGetData_after_empty() {
+    info(`Test asyncGetData request after empty on ${type}`);
+
+    let str = writeRandomStringToClipboard("text/plain", type);
+    let request = await asyncGetClipboardData(type);
+    isDeeply(request.flavorList, ["text/plain"], "Check flavorList");
+    is(
+      await asyncClipboardRequestGetData(request, "text/plain"),
+      str,
+      "Check data"
+    );
+    ok(request.valid, "request should still be valid");
+
+    // Empty clipboard data
+    emptyClipboardData(type);
+    is(getClipboardData("text/plain", type), null, "ensure clipboard is empty");
+
+    await asyncClipboardRequestGetData(request, "text/plain").then(
+      () => {
+        ok(false, "asyncClipboardRequestGetData should not success");
+      },
+      e => {
+        ok(true, "asyncClipboardRequestGetData should reject");
+      }
+    );
+    ok(!request.valid, "request should no longer be valid");
+
+    info(`check clipboard data again`);
+    request = await asyncGetClipboardData(type);
+    isDeeply(request.flavorList, [], "Check flavorList");
+
+    cleanupAllClipboard();
+  });
+});
+
+add_task(async function test_html_data() {
+  info(`Test asyncGetData request with html data`);
+
+  const html_str = `<img src="https://example.com/oops">`;
+  writeStringToClipboard(html_str, "text/html", clipboard.kGlobalClipboard);
+
+  let request = await asyncGetClipboardData(clipboard.kGlobalClipboard);
+  isDeeply(request.flavorList, ["text/html"], "Check flavorList");
+  is(
+    await asyncClipboardRequestGetData(request, "text/html"),
+    // On Windows, widget adds extra data into HTML clipboard.
+    navigator.platform.includes("Win")
+      ? `<html><body>\n<!--StartFragment-->${html_str}<!--EndFragment-->\n</body>\n</html>`
+      : html_str,
+    "Check data"
+  );
+  // Requesting a flavor that is not in the list should throw error.
+  await asyncClipboardRequestGetData(request, "text/plain", true).catch(
+    () => {}
+  );
+});
diff --git a/widget/tests/file_test_clipboard_asyncSetData.js b/widget/tests/file_test_clipboard_asyncSetData.js
new file mode 100644
index 0000000000..cceecd2c44
--- /dev/null
+++ b/widget/tests/file_test_clipboard_asyncSetData.js
@@ -0,0 +1,179 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* import-globals-from clipboard_helper.js */
+
+"use strict";
+
+clipboardTypes.forEach(function (type) {
+  if (clipboard.isClipboardTypeSupported(type)) {
+    clipboardTypes.forEach(function (otherType) {
+      if (clipboard.isClipboardTypeSupported(otherType)) {
+        [true, false].forEach(async function (async) {
+          add_task(async function test_clipboard_pending_asyncSetData() {
+            info(
+              `Test having a pending asyncSetData request on ${type} and then make a new ${
+                async ? "asyncSetData" : "setData"
+              } request on ${otherType}`
+            );
+
+            // Create a pending asyncSetData request
+            let priorResult;
+            let priorRequest;
+            let priorPromise = new Promise(resolve => {
+              priorRequest = clipboard.asyncSetData(type, {
+                QueryInterface: SpecialPowers.ChromeUtils.generateQI([
+                  "nsIAsyncSetClipboardDataCallback",
+                ]),
+                onComplete(rv) {
+                  priorResult = rv;
+                  resolve();
+                },
+              });
+            });
+
+            // Create a new request
+            let str = writeRandomStringToClipboard(
+              "text/plain",
+              otherType,
+              null,
+              async
+            );
+
+            if (type === otherType) {
+              info(
+                "The new request to the same clipboard type should cancel the prior pending request"
+              );
+              await priorPromise;
+
+              is(
+                priorResult,
+                Cr.NS_ERROR_ABORT,
+                "The pending asyncSetData request should be canceled"
+              );
+              try {
+                priorRequest.setData(
+                  generateNewTransferable("text/plain", generateRandomString())
+                );
+                ok(
+                  false,
+                  "An error should be thrown if setData is called on a canceled clipboard request"
+                );
+              } catch (e) {
+                is(
+                  e.result,
+                  Cr.NS_ERROR_FAILURE,
+                  "An error should be thrown if setData is called on a canceled clipboard request"
+                );
+              }
+            } else {
+              info(
+                "The new request to the different clipboard type should not cancel the prior pending request"
+              );
+              str = generateRandomString();
+              priorRequest.setData(
+                generateNewTransferable("text/plain", str),
+                null
+              );
+              await priorPromise;
+
+              is(
+                priorResult,
+                Cr.NS_OK,
+                "The pending asyncSetData request should success"
+              );
+
+              try {
+                priorRequest.setData(
+                  generateNewTransferable("text/plain", generateRandomString())
+                );
+                ok(
+                  false,
+                  "Calling setData multiple times should throw an error"
+                );
+              } catch (e) {
+                is(
+                  e.result,
+                  Cr.NS_ERROR_FAILURE,
+                  "Calling setData multiple times should throw an error"
+                );
+              }
+            }
+
+            // Test clipboard data.
+            is(
+              getClipboardData("text/plain", type),
+              str,
+              `Test clipboard data for type ${type}`
+            );
+
+            // Clean clipboard data.
+            cleanupAllClipboard();
+          });
+        });
+      }
+    });
+
+    add_task(async function test_clipboard_asyncSetData_abort() {
+      info(`Test abort asyncSetData request on ${type}`);
+
+      // Create a pending asyncSetData request
+      let result;
+      let request = clipboard.asyncSetData(type, rv => {
+        result = rv;
+      });
+
+      // Abort with NS_OK.
+      try {
+        request.abort(Cr.NS_OK);
+        ok(false, "Throw an error when attempting to abort with NS_OK");
+      } catch (e) {
+        is(
+          e.result,
+          Cr.NS_ERROR_FAILURE,
+          "Should throw an error when attempting to abort with NS_OK"
+        );
+      }
+      is(result, undefined, "The asyncSetData request should not be canceled");
+
+      // Abort with NS_ERROR_ABORT.
+      request.abort(Cr.NS_ERROR_ABORT);
+      is(
+        result,
+        Cr.NS_ERROR_ABORT,
+        "The asyncSetData request should be canceled"
+      );
+      try {
+        request.abort(Cr.NS_ERROR_FAILURE);
+        ok(false, "Throw an error when attempting to abort again");
+      } catch (e) {
+        is(
+          e.result,
+          Cr.NS_ERROR_FAILURE,
+          "Should throw an error when attempting to abort again"
+        );
+      }
+      is(
+        result,
+        Cr.NS_ERROR_ABORT,
+        "The callback should not be notified again"
+      );
+
+      try {
+        request.setData(
+          generateNewTransferable("text/plain", generateRandomString())
+        );
+        ok(
+          false,
+          "An error should be thrown if setData is called on a canceled clipboard request"
+        );
+      } catch (e) {
+        is(
+          e.result,
+          Cr.NS_ERROR_FAILURE,
+          "An error should be thrown if setData is called on a canceled clipboard request"
+        );
+      }
+    });
+  }
+});
diff --git a/widget/tests/file_test_ime_state_in_contenteditable_on_readonly_change.js b/widget/tests/file_test_ime_state_in_contenteditable_on_readonly_change.js
new file mode 100644
index 0000000000..9f1ab2d305
--- /dev/null
+++ b/widget/tests/file_test_ime_state_in_contenteditable_on_readonly_change.js
@@ -0,0 +1,616 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from file_ime_state_test_helper.js */
+
+class IMEStateInContentEditableOnReadonlyChangeTester {
+  // Runner only fields.
+  #mEditingHost;
+  #mFocusElement;
+  #mWindow;
+
+  // Tester only fields.
+  #mTIPWrapper;
+  #mWindowUtils;
+
+  clear() {
+    this.#mTIPWrapper?.clearFocusBlurNotifications();
+    this.#mTIPWrapper = null;
+  }
+
+  #flushPendingIMENotifications() {
+    return new Promise(resolve =>
+      this.#mWindow.requestAnimationFrame(() =>
+        this.#mWindow.requestAnimationFrame(resolve)
+      )
+    );
+  }
+
+  #getExpectedIMEState() {
+    // Although if this.#mFocusElement is a <button>, its `.focus()` call
+    // focus it, but caret is not set into it and following typing is handled
+    // outside the <button>.  Therefore, anyway the enabled state should be
+    // "enabled".
+    return SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED;
+  }
+
+  /**
+   * @param {Element} aEditingHost  The editing host.
+   * @param {Element} aFocusElement Element which should have focus.  This must
+   * be an inclusive descendant of the editing host and editable element.
+   * @param {Window} aWindow [optional] The window.
+   * @returns {object} Expected result of initial state.
+   */
+  async prepareToRun(aEditingHost, aFocusElement, aWindow = window) {
+    this.#mWindow = aWindow;
+    this.#mEditingHost = aEditingHost;
+    this.#mFocusElement = aFocusElement;
+
+    if (this.#mEditingHost.ownerDocument.activeElement) {
+      this.#mEditingHost.ownerDocument.activeElement.blur();
+      await this.#flushPendingIMENotifications();
+    }
+
+    this.#mWindow.focus();
+    this.#mEditingHost.setAttribute("contenteditable", "");
+    this.#mFocusElement.focus();
+
+    await this.#flushPendingIMENotifications();
+
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when initialized with setting focus to ${
+        this.#mFocusElement == this.#mEditingHost
+          ? "the editing host"
+          : `<${this.#mFocusElement.tagName.toLowerCase()}>`
+      }`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  /**
+   * @param {object} aExpectedResult The expected result of the test.
+   */
+  #checkResult(aExpectedResult) {
+    const description = `IMEStateInContentEditableOnReadonlyChangeTester`;
+    is(
+      this.#mWindowUtils.IMEStatus,
+      aExpectedResult.expectedIMEState,
+      `${description}: IME enabled state should be expected one ${aExpectedResult.description}`
+    );
+    is(
+      this.#mTIPWrapper.IMEHasFocus,
+      aExpectedResult.expectedIMEFocus,
+      `${description}: IME should ${
+        aExpectedResult.expectedIMEFocus ? "" : "not "
+      }have focus ${aExpectedResult.description}`
+    );
+  }
+
+  /**
+   * @param {object} aExpectedResult The expected result of prepareToRun().
+   * @param {Window} aWindow The window to check IME state.
+   * @param {TIPWrapper} aTIPWrapper The TIPWrapper for aWindow.
+   */
+  checkResultOfPreparation(aExpectedResult, aWindow, aTIPWrapper) {
+    this.#mWindowUtils = SpecialPowers.wrap(aWindow).windowUtils;
+    this.#mTIPWrapper = aTIPWrapper;
+    this.#checkResult(aExpectedResult);
+  }
+
+  /**
+   * @returns {object} The expected result.
+   */
+  async runToMakeHTMLEditorReadonly() {
+    const htmlEditor = SpecialPowers.wrap(this.#mWindow).docShell.editor;
+    htmlEditor.flags |= SpecialPowers.Ci.nsIEditor.eEditorReadonlyMask;
+
+    await this.#flushPendingIMENotifications();
+
+    return {
+      description:
+        this.#mFocusElement == this.#mEditingHost
+          ? "when the editing host has focus"
+          : `when <${this.#mFocusElement.tagName.toLowerCase()}> has focus`,
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      expectedIMEFocus: false,
+    };
+  }
+
+  /**
+   * @param {object} aExpectedResult The expected result of runToMakeHTMLEditorReadonly().
+   */
+  checkResultOfMakingHTMLEditorReadonly(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+  }
+
+  /**
+   * @returns {object} The expected result.
+   */
+  async runToMakeHTMLEditorEditable() {
+    const htmlEditor = SpecialPowers.wrap(this.#mWindow).docShell.editor;
+    htmlEditor.flags &= ~SpecialPowers.Ci.nsIEditor.eEditorReadonlyMask;
+
+    await this.#flushPendingIMENotifications();
+
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description:
+        this.#mFocusElement == this.#mEditingHost
+          ? "when the editing host has focus"
+          : `when <${this.#mFocusElement.tagName.toLowerCase()}> has focus`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  /**
+   * @param {object} aExpectedResult The expected result of runToMakeHTMLEditorEditable().
+   */
+  checkResultOfMakingHTMLEditorEditable(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+  }
+
+  async runToRemoveContentEditableAttribute() {
+    this.#mEditingHost.removeAttribute("contenteditable");
+
+    await this.#flushPendingIMENotifications();
+
+    return {
+      description:
+        this.#mFocusElement == this.#mEditingHost
+          ? "after removing contenteditable attribute when the editing host has focus"
+          : `after removing contenteditable attribute when <${this.#mFocusElement.tagName.toLowerCase()}> has focus`,
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      expectedIMEFocus: false,
+    };
+  }
+
+  /**
+   * @param {object} aExpectedResult The expected result of runToRemoveContentEditableAttribute().
+   */
+  checkResultOfRemovingContentEditableAttribute(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+  }
+}
+
+class IMEStateOfTextControlInContentEditableOnReadonlyChangeTester {
+  static #sTextControls = [
+    {
+      tag: "input",
+      type: "text",
+      readonly: false,
+    },
+    {
+      tag: "input",
+      type: "text",
+      readonly: true,
+    },
+    {
+      tag: "textarea",
+      readonly: false,
+    },
+    {
+      tag: "textarea",
+      readonly: true,
+    },
+  ];
+
+  static get numberOfTextControlTypes() {
+    return IMEStateOfTextControlInContentEditableOnReadonlyChangeTester
+      .#sTextControls.length;
+  }
+
+  static #createElement(aDocument, aTextControl) {
+    const textControl = aDocument.createElement(aTextControl.tag);
+    if (aTextControl.type !== undefined) {
+      textControl.setAttribute("type", aTextControl.type);
+    }
+    if (aTextControl.readonly) {
+      textControl.setAttribute("readonly", "");
+    }
+    return textControl;
+  }
+
+  #getDescription() {
+    return `<${this.#mTextControl.tag}${
+      this.#mTextControl.type !== undefined
+        ? ` type=${this.#mTextControl.type}`
+        : ""
+    }${this.#mTextControl.readonly ? " readonly" : ""}>`;
+  }
+
+  #getExpectedIMEState() {
+    return this.#mTextControl.readonly
+      ? SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED
+      : SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED;
+  }
+
+  #flushPendingIMENotifications() {
+    return new Promise(resolve =>
+      this.#mWindow.requestAnimationFrame(() =>
+        this.#mWindow.requestAnimationFrame(resolve)
+      )
+    );
+  }
+
+  // Runner only fields.
+  #mEditingHost;
+  #mTextControl;
+  #mTextControlElement;
+  #mWindow;
+
+  // Checker only fields.
+  #mWindowUtils;
+  #mTIPWrapper;
+
+  clear() {
+    this.#mTIPWrapper?.clearFocusBlurNotifications();
+    this.#mTIPWrapper = null;
+  }
+
+  /**
+   * @param {number} aIndex Index of the test.
+   * @param {Element} aEditingHost The editing host which will have a text control.
+   * @param {Window} aWindow [optional] The DOM window containing aEditingHost.
+   * @returns {object} Expected result of initial state.
+   */
+  async prepareToRun(aIndex, aEditingHost, aWindow = window) {
+    this.#mWindow = aWindow;
+    this.#mEditingHost = aEditingHost;
+    this.#mEditingHost.ownerDocument.activeElement?.blur();
+    this.#mEditingHost.removeAttribute("contenteditable");
+    this.#mTextControlElement?.remove();
+    await this.#flushPendingIMENotifications();
+    this.#mTextControl =
+      IMEStateOfTextControlInContentEditableOnReadonlyChangeTester.#sTextControls[
+        aIndex
+      ];
+    this.#mTextControlElement =
+      IMEStateOfTextControlInContentEditableOnReadonlyChangeTester.#createElement(
+        this.#mEditingHost.ownerDocument,
+        this.#mTextControl
+      );
+    this.#mEditingHost.appendChild(this.#mTextControlElement);
+    this.#mTextControlElement.focus();
+    await this.#flushPendingIMENotifications();
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when ${this.#getDescription()} simply has focus`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  #checkResult(aExpectedResult) {
+    const description =
+      "IMEStateOfTextControlInContentEditableOnReadonlyChangeTester";
+    is(
+      this.#mWindowUtils.IMEStatus,
+      aExpectedResult.expectedIMEState,
+      `${description}: IME state should be proper one for the text control ${aExpectedResult.description}`
+    );
+    is(
+      this.#mTIPWrapper.IMEHasFocus,
+      aExpectedResult.expectedIMEFocus,
+      `${description}: IME should ${
+        aExpectedResult.expectedIMEFocus ? "" : "not "
+      }have focus ${aExpectedResult.description}`
+    );
+  }
+
+  /**
+   * @param {object} aExpectedResult The expected result returned by prepareToRun().
+   * @param {Window} aWindow The window whose IME state should be checked.
+   * @param {TIPWrapper} aTIPWrapper The TIP wrapper of aWindow.
+   */
+  checkResultOfPreparation(aExpectedResult, aWindow, aTIPWrapper) {
+    this.#mWindowUtils = SpecialPowers.wrap(aWindow).windowUtils;
+    this.#mTIPWrapper = aTIPWrapper;
+    this.#checkResult(aExpectedResult);
+  }
+
+  async runToMakeParentEditingHost() {
+    this.#mEditingHost.setAttribute("contenteditable", "");
+    await this.#flushPendingIMENotifications();
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when parent of ${this.#getDescription()} becomes contenteditable`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  checkResultOfMakingParentEditingHost(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+  }
+
+  async runToMakeHTMLEditorReadonly() {
+    const editor = SpecialPowers.wrap(this.#mWindow).docShell.editor;
+    editor.flags |= SpecialPowers.Ci.nsIEditor.eEditorReadonlyMask;
+    await this.#flushPendingIMENotifications();
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when HTMLEditor for parent of ${this.#getDescription()} becomes readonly`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  checkResultOfMakingHTMLEditorReadonly(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+  }
+
+  async runToMakeHTMLEditorEditable() {
+    const editor = SpecialPowers.wrap(this.#mWindow).docShell.editor;
+    editor.flags &= ~SpecialPowers.Ci.nsIEditor.eEditorReadonlyMask;
+    await this.#flushPendingIMENotifications();
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when HTMLEditor for parent of ${this.#getDescription()} becomes editable`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  checkResultOfMakingHTMLEditorEditable(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+  }
+
+  async runToMakeParentNonEditingHost() {
+    this.#mEditingHost.removeAttribute("contenteditable");
+    await this.#flushPendingIMENotifications();
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when parent of ${this.#getDescription()} becomes non-editable`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  checkResultOfMakingParentNonEditable(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+  }
+}
+
+class IMEStateOutsideContentEditableOnReadonlyChangeTester {
+  static #sFocusTargets = [
+    {
+      tag: "input",
+      type: "text",
+      readonly: false,
+    },
+    {
+      tag: "input",
+      type: "text",
+      readonly: true,
+    },
+    {
+      tag: "textarea",
+      readonly: false,
+    },
+    {
+      tag: "textarea",
+      readonly: true,
+    },
+    {
+      tag: "button",
+    },
+    {
+      tag: "body",
+    },
+  ];
+
+  static get numberOfFocusTargets() {
+    return IMEStateOutsideContentEditableOnReadonlyChangeTester.#sFocusTargets
+      .length;
+  }
+
+  static #maybeCreateElement(aDocument, aFocusTarget) {
+    if (aFocusTarget.tag == "body") {
+      return null;
+    }
+    const element = aDocument.createElement(aFocusTarget.tag);
+    if (aFocusTarget.type !== undefined) {
+      element.setAttribute("type", aFocusTarget.type);
+    }
+    if (aFocusTarget.readonly) {
+      element.setAttribute("readonly", "");
+    }
+    return element;
+  }
+
+  #getDescription() {
+    return `<${this.#mFocusTarget.tag}${
+      this.#mFocusTarget.type !== undefined
+        ? ` type=${this.#mFocusTarget.type}`
+        : ""
+    }${this.#mFocusTarget.readonly ? " readonly" : ""}>`;
+  }
+
+  #getExpectedIMEState() {
+    return this.#mFocusTarget.readonly ||
+      this.#mFocusTarget.tag == "button" ||
+      this.#mFocusTarget.tag == "body"
+      ? SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED
+      : SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED;
+  }
+
+  #flushPendingIMENotifications() {
+    return new Promise(resolve =>
+      this.#mWindow.requestAnimationFrame(() =>
+        this.#mWindow.requestAnimationFrame(resolve)
+      )
+    );
+  }
+
+  // Runner only fields.
+  #mBody;
+  #mEditingHost;
+  #mFocusTarget;
+  #mFocusTargetElement;
+  #mWindow;
+
+  // Checker only fields.
+  #mWindowUtils;
+  #mTIPWrapper;
+
+  clear() {
+    this.#mTIPWrapper?.clearFocusBlurNotifications();
+    this.#mTIPWrapper = null;
+  }
+
+  /**
+   * @param {number} aIndex Index of the test.
+   * @param {Element} aEditingHost The editing host.
+   * @param {Window} aWindow [optional] The DOM window containing aEditingHost.
+   * @returns {object} Expected result of initial state.
+   */
+  async prepareToRun(aIndex, aEditingHost, aWindow = window) {
+    this.#mWindow = aWindow;
+    this.#mEditingHost = aEditingHost;
+    this.#mEditingHost.removeAttribute("contenteditable");
+    this.#mBody = this.#mEditingHost.ownerDocument.body;
+    this.#mBody.ownerDocument.activeElement?.blur();
+    if (this.#mFocusTargetElement != this.#mBody) {
+      this.#mFocusTargetElement?.remove();
+    }
+    await this.#flushPendingIMENotifications();
+    this.#mFocusTarget =
+      IMEStateOutsideContentEditableOnReadonlyChangeTester.#sFocusTargets[
+        aIndex
+      ];
+    this.#mFocusTargetElement =
+      IMEStateOutsideContentEditableOnReadonlyChangeTester.#maybeCreateElement(
+        this.#mBody.ownerDocument,
+        this.#mFocusTarget
+      );
+    if (this.#mFocusTargetElement) {
+      this.#mBody.appendChild(this.#mFocusTargetElement);
+      this.#mFocusTargetElement.focus();
+    }
+    await this.#flushPendingIMENotifications();
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when ${this.#getDescription()} simply has focus`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  #checkResult(aExpectedResult) {
+    const description = "IMEStateOutsideContentEditableOnReadonlyChangeTester";
+    is(
+      this.#mWindowUtils.IMEStatus,
+      aExpectedResult.expectedIMEState,
+      `${description}: IME state should be proper one for the focused element ${aExpectedResult.description}`
+    );
+    is(
+      this.#mTIPWrapper.IMEHasFocus,
+      aExpectedResult.expectedIMEFocus,
+      `${description}: IME should ${
+        aExpectedResult.expectedIMEFocus ? "" : "not "
+      }have focus ${aExpectedResult.description}`
+    );
+  }
+
+  /**
+   * @param {object} aExpectedResult The expected result returned by prepareToRun().
+   * @param {Window} aWindow The window whose IME state should be checked.
+   * @param {TIPWrapper} aTIPWrapper The TIP wrapper of aWindow.
+   */
+  checkResultOfPreparation(aExpectedResult, aWindow, aTIPWrapper) {
+    this.#mWindowUtils = SpecialPowers.wrap(aWindow).windowUtils;
+    this.#mTIPWrapper = aTIPWrapper;
+    this.#checkResult(aExpectedResult);
+  }
+
+  async runToMakeParentEditingHost() {
+    this.#mEditingHost.setAttribute("contenteditable", "");
+    await this.#flushPendingIMENotifications();
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when parent of ${this.#getDescription()} becomes contenteditable`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  checkResultOfMakingParentEditingHost(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+  }
+
+  async runToMakeHTMLEditorReadonly() {
+    const editor = SpecialPowers.wrap(this.#mWindow).docShell.editor;
+    editor.flags |= SpecialPowers.Ci.nsIEditor.eEditorReadonlyMask;
+    await this.#flushPendingIMENotifications();
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when HTMLEditor for parent of ${this.#getDescription()} becomes readonly`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  checkResultOfMakingHTMLEditorReadonly(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+  }
+
+  async runToMakeHTMLEditorEditable() {
+    const editor = SpecialPowers.wrap(this.#mWindow).docShell.editor;
+    editor.flags &= ~SpecialPowers.Ci.nsIEditor.eEditorReadonlyMask;
+    await this.#flushPendingIMENotifications();
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when HTMLEditor for parent of ${this.#getDescription()} becomes editable`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  checkResultOfMakingHTMLEditorEditable(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+  }
+
+  async runToMakeParentNonEditingHost() {
+    this.#mEditingHost.removeAttribute("contenteditable");
+    await this.#flushPendingIMENotifications();
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when parent of ${this.#getDescription()} becomes non-editable`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  checkResultOfMakingParentNonEditable(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+  }
+}
diff --git a/widget/tests/file_test_ime_state_in_text_control_on_reframe.js b/widget/tests/file_test_ime_state_in_text_control_on_reframe.js
new file mode 100644
index 0000000000..719022b889
--- /dev/null
+++ b/widget/tests/file_test_ime_state_in_text_control_on_reframe.js
@@ -0,0 +1,190 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from file_ime_state_test_helper.js */
+
+// Bug 580388 and bug 808287
+class IMEStateInTextControlOnReframeTester {
+  static #sTextControls = [
+    {
+      tag: "input",
+      type: "text",
+    },
+    {
+      tag: "input",
+      type: "password",
+    },
+    {
+      tag: "textarea",
+    },
+  ];
+
+  static get numberOfTextControlTypes() {
+    return IMEStateInTextControlOnReframeTester.#sTextControls.length;
+  }
+
+  #createElement() {
+    const textControl = this.#mDocument.createElement(this.#mTextControl.tag);
+    if (this.#mTextControl.type !== undefined) {
+      textControl.setAttribute("type", this.#mTextControl.type);
+    }
+    return textControl;
+  }
+
+  #getDescription() {
+    return `<${this.#mTextControl.tag}${
+      this.#mTextControl.type !== undefined
+        ? ` type=${this.#mTextControl.type}`
+        : ""
+    }>`;
+  }
+
+  #getExpectedIMEState() {
+    return this.#mTextControl.type == "password"
+      ? SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_PASSWORD
+      : SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED;
+  }
+
+  #flushPendingIMENotifications() {
+    return new Promise(resolve =>
+      this.#mWindow.requestAnimationFrame(() =>
+        this.#mWindow.requestAnimationFrame(resolve)
+      )
+    );
+  }
+
+  // Runner only fields.
+  #mTextControl;
+  #mTextControlElement;
+  #mWindow;
+  #mDocument;
+
+  // Checker only fields.
+  #mWindowUtils;
+  #mTIPWrapper;
+
+  clear() {
+    this.#mTIPWrapper?.clearFocusBlurNotifications();
+    this.#mTIPWrapper = null;
+  }
+
+  /**
+   * @param {number} aIndex Index of the test.
+   * @param {Element} aDocument The document to run the test.
+   * @param {Window} aWindow [optional] The DOM window for aDocument.
+   * @returns {object} Expected result of initial state.
+   */
+  async prepareToRun(aIndex, aDocument, aWindow = window) {
+    this.#mWindow = aWindow;
+    this.#mDocument = aDocument;
+    this.#mDocument.activeElement?.blur();
+    this.#mTextControlElement?.remove();
+    await this.#flushPendingIMENotifications();
+    this.#mTextControl =
+      IMEStateInTextControlOnReframeTester.#sTextControls[aIndex];
+    this.#mTextControlElement = this.#createElement();
+    this.#mDocument.body.appendChild(this.#mTextControlElement);
+    this.#mTextControlElement.focus();
+    this.#mTextControlElement.style.overflow = "visible";
+    this.#mTextControlElement.addEventListener(
+      "input",
+      aEvent => {
+        aEvent.target.style.overflow = "hidden";
+      },
+      {
+        capture: true,
+      }
+    );
+    await this.#flushPendingIMENotifications();
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when ${this.#getDescription()} has focus`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      expectedNumberOfFocusNotifications: 1,
+    };
+  }
+
+  #checkResult(aExpectedResult) {
+    const description = "IMEStateInTextControlOnReframeTester";
+    is(
+      this.#mWindowUtils.IMEStatus,
+      aExpectedResult.expectedIMEState,
+      `${description}: IME state should be proper one for the text control ${aExpectedResult.description}`
+    );
+    is(
+      this.#mTIPWrapper.IMEHasFocus,
+      aExpectedResult.expectedIMEFocus,
+      `${description}: IME should ${
+        aExpectedResult.expectedIMEFocus ? "" : "not "
+      }have focus ${aExpectedResult.description}`
+    );
+    if (aExpectedResult.numberOfFocusNotifications !== undefined) {
+      is(
+        this.#mTIPWrapper.numberOfFocusNotifications,
+        aExpectedResult.numberOfFocusNotifications,
+        `${description}: focus notifications should've been received ${
+          this.#mTIPWrapper.numberOfFocusNotifications
+        } times ${aExpectedResult.description}`
+      );
+    }
+    if (aExpectedResult.numberOfBlurNotifications !== undefined) {
+      is(
+        this.#mTIPWrapper.numberOfBlurNotifications,
+        aExpectedResult.numberOfBlurNotifications,
+        `${description}: blur notifications should've been received ${
+          this.#mTIPWrapper.numberOfBlurNotifications
+        } times ${aExpectedResult.description}`
+      );
+    }
+  }
+
+  /**
+   * @param {object} aExpectedResult The expected result returned by prepareToRun().
+   * @param {Window} aWindow The window whose IME state should be checked.
+   * @param {TIPWrapper} aTIPWrapper The TIP wrapper of aWindow.
+   */
+  checkResultAfterTypingA(aExpectedResult, aWindow, aTIPWrapper) {
+    this.#mWindowUtils = SpecialPowers.wrap(aWindow).windowUtils;
+    this.#mTIPWrapper = aTIPWrapper;
+    this.#checkResult(aExpectedResult);
+
+    this.#mTIPWrapper.clearFocusBlurNotifications();
+  }
+
+  async prepareToRun2() {
+    this.#mTextControlElement.addEventListener("focus", aEvent => {
+      // Perform a style change and flush it to trigger reframing.
+      aEvent.target.style.overflow = "visible";
+      aEvent.target.getBoundingClientRect();
+    });
+    this.#mTextControlElement.blur();
+    this.#mTextControlElement.focus();
+
+    await this.#flushPendingIMENotifications();
+
+    const expectedIMEState = this.#getExpectedIMEState();
+    return {
+      description: `when ${this.#getDescription()} is reframed by focus event listener`,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      expectedNumberOfFocusNotifications: 1,
+      expectedNumberOfBlurNotifications: 1,
+    };
+  }
+
+  /**
+   * @param {object} aExpectedResult The expected result returned by prepareToRun().
+   */
+  checkResultAfterTypingA2(aExpectedResult) {
+    this.#checkResult(aExpectedResult);
+
+    this.#mTIPWrapper.clearFocusBlurNotifications();
+  }
+}
diff --git a/widget/tests/file_test_ime_state_on_focus_move.js b/widget/tests/file_test_ime_state_on_focus_move.js
new file mode 100644
index 0000000000..f7760d8a09
--- /dev/null
+++ b/widget/tests/file_test_ime_state_on_focus_move.js
@@ -0,0 +1,1588 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from file_ime_state_test_helper.js */
+
+class IMEStateWhenNoActiveElementTester {
+  #mDescription;
+
+  constructor(aDescription) {
+    this.#mDescription = aDescription;
+  }
+
+  async run(aDocument, aWindow = window) {
+    aWindow.focus();
+    aDocument.activeElement?.blur();
+
+    await new Promise(resolve =>
+      requestAnimationFrame(() => requestAnimationFrame(resolve))
+    ); // wait for sending IME notifications
+
+    return { designModeValue: aDocument.designMode };
+  }
+
+  check(aExpectedData, aWindow = window) {
+    const winUtils = SpecialPowers.wrap(aWindow).windowUtils;
+    if (aExpectedData.designModeValue == "on") {
+      is(
+        winUtils.IMEStatus,
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+        `IMEStateWhenNoActiveElementTester(${
+          this.#mDescription
+        }): When no element has focus, IME should stay enabled in design mode`
+      );
+    } else {
+      is(
+        winUtils.IMEStatus,
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+        `IMEStateWhenNoActiveElementTester(${
+          this.#mDescription
+        }): When no element has focus, IME should be disabled`
+      );
+    }
+  }
+}
+
+class IMEStateOnFocusMoveTester {
+  // Common fields
+  #mDescription;
+  #mTest;
+  #mWindow;
+  #mWindowUtils;
+
+  // Only runner fields
+  #mCreatedElement;
+  #mCreatedElementForPreviousFocusedElement;
+  #mElementToSetFocus;
+  #mContainerIsEditable;
+
+  // Only checker fields
+  #mTIPWrapper;
+
+  constructor(aDescription, aIndex, aWindow = window) {
+    this.#mTest = IMEStateOnFocusMoveTester.#sTestList[aIndex];
+    this.#mDescription = `IMEStateOnFocusMoveTester(${aDescription}): ${
+      this.#mTest.description
+    }`;
+    this.#mWindow = aWindow;
+    this.#mWindowUtils = SpecialPowers.wrap(this.#mWindow).windowUtils;
+  }
+
+  /**
+   * prepareToRun should be called before run only in the process which will run the test.
+   */
+  async prepareToRun(aContainer) {
+    const doc = aContainer.ownerDocument;
+    this.#mTest = this.#resolveTest(this.#mTest, aContainer);
+    this.#mContainerIsEditable = nodeIsEditable(aContainer);
+    this.#mCreatedElement = this.#mTest.createElement(doc);
+    const waitForLoadIfIFrame = new Promise(resolve => {
+      if (this.#mCreatedElement.tagName == "IFRAME") {
+        this.#mCreatedElement.addEventListener("load", resolve, {
+          capture: true,
+          once: true,
+        });
+      } else {
+        resolve();
+      }
+    });
+    aContainer.appendChild(this.#mCreatedElement);
+    await waitForLoadIfIFrame;
+    this.#mElementToSetFocus = this.#mCreatedElement.contentDocument
+      ? this.#mCreatedElement.contentDocument.documentElement
+      : this.#mCreatedElement;
+    if (doc.designMode == "on") {
+      doc.activeElement?.blur();
+    } else if (this.#mContainerIsEditable) {
+      getEditingHost(aContainer).focus(); // FIXME: use editing host instead
+    } else {
+      this.#mCreatedElementForPreviousFocusedElement =
+        doc.createElement("input");
+      this.#mCreatedElementForPreviousFocusedElement.setAttribute(
+        "type",
+        this.#mTest.expectedEnabledValue ==
+          SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED
+          ? "password"
+          : "text"
+      );
+      aContainer.appendChild(this.#mCreatedElementForPreviousFocusedElement);
+      this.#mCreatedElementForPreviousFocusedElement.focus();
+    }
+
+    await new Promise(resolve =>
+      requestAnimationFrame(() => requestAnimationFrame(resolve))
+    ); // wait for sending IME notifications
+
+    return {
+      designModeValue: doc.designMode,
+      containerIsEditable: this.#mContainerIsEditable,
+      isFocusable: this.#mTest.isFocusable,
+      focusEventFired: this.#mTest.focusEventIsExpected,
+      enabledValue: this.#mTest.expectedEnabledValue,
+      testedSubDocumentInDesignMode:
+        this.#mCreatedElement.contentDocument?.designMode == "on",
+    };
+  }
+
+  /**
+   * prepareToCheck should be called before calling run only in the process which will check the result.
+   */
+  prepareToCheck(aExpectedData, aTIPWrapper) {
+    info(`Starting ${this.#mDescription} (enable state check)...`);
+    this.#mTIPWrapper = aTIPWrapper;
+    this.#mTIPWrapper.onIMEFocusBlur = aNotificationType => {
+      switch (aNotificationType) {
+        case "notify-focus":
+          info(aNotificationType);
+          is(
+            this.#mWindowUtils.IMEStatus,
+            aExpectedData.enabledValue,
+            `${
+              this.#mDescription
+            }, IME should receive a focus notification after IME state is updated`
+          );
+          break;
+        case "notify-blur":
+          info(aNotificationType);
+          const changingStatus = !(
+            aExpectedData.containerIsEditable &&
+            aExpectedData.enabledValue ==
+              SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED
+          );
+          if (aExpectedData.designModeValue == "on") {
+            is(
+              // FIXME: This is odd, but #mWindowUtils.IMEStatus sometimes IME_STATUS_PASSWORD
+              SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+              aExpectedData.enabledValue,
+              `${
+                this.#mDescription
+              }, IME should receive a blur notification after IME state is updated`
+            );
+          } else if (changingStatus) {
+            isnot(
+              this.#mWindowUtils.IMEStatus,
+              aExpectedData.enabledValue,
+              `${
+                this.#mDescription
+              }, IME should receive a blur notification BEFORE IME state is updated`
+            );
+          } else {
+            is(
+              this.#mWindowUtils.IMEStatus,
+              aExpectedData.enabledValue,
+              `${
+                this.#mDescription
+              }, IME should receive a blur notification and its context has expected IME state if the state isn't being changed`
+            );
+          }
+          break;
+      }
+    };
+
+    this.#mTIPWrapper.clearFocusBlurNotifications();
+  }
+
+  /**
+   * @returns {bool} whether expected element has focus or not after moving focus.
+   */
+  async run() {
+    const previousFocusedElement = getFocusedElementOrUAWidgetHost();
+    if (this.#mTest.setFocusIntoUAWidget) {
+      this.#mTest.setFocusIntoUAWidget(this.#mElementToSetFocus);
+    } else {
+      this.#mElementToSetFocus.focus();
+    }
+
+    await new Promise(resolve =>
+      requestAnimationFrame(() => requestAnimationFrame(resolve))
+    ); // wait for sending IME notifications
+
+    const currentFocusedElement = getFocusedElementOrUAWidgetHost();
+    this.#mCreatedElementForPreviousFocusedElement?.remove();
+    if (this.#mTest.isFocusable) {
+      return this.#mElementToSetFocus == currentFocusedElement;
+    }
+    return previousFocusedElement == currentFocusedElement;
+  }
+
+  check(aExpectedData) {
+    this.#mTIPWrapper.onIMEFocusBlur = null;
+
+    if (aExpectedData.isFocusable) {
+      if (aExpectedData.focusEventFired) {
+        if (
+          aExpectedData.enabledValue ==
+            SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED ||
+          aExpectedData.enabledValue ==
+            SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_PASSWORD
+        ) {
+          ok(
+            this.#mTIPWrapper.numberOfFocusNotifications > 0,
+            `${this.#mDescription}, IME should receive a focus notification`
+          );
+          if (
+            aExpectedData.designModeValue == "on" &&
+            !aExpectedData.testedSubDocumentInDesignMode
+          ) {
+            is(
+              this.#mTIPWrapper.numberOfBlurNotifications,
+              0,
+              `${
+                this.#mDescription
+              }, IME shouldn't receive a blur notification in designMode since focus isn't moved from another editor`
+            );
+          } else {
+            ok(
+              this.#mTIPWrapper.numberOfBlurNotifications > 0,
+              `${
+                this.#mDescription
+              }, IME should receive a blur notification for the previous focused editor`
+            );
+          }
+          ok(
+            this.#mTIPWrapper.IMEHasFocus,
+            `${this.#mDescription}, IME should have focus right now`
+          );
+        } else {
+          is(
+            this.#mTIPWrapper.numberOfFocusNotifications,
+            0,
+            `${this.#mDescription}, IME shouldn't receive a focus notification`
+          );
+          ok(
+            this.#mTIPWrapper.numberOfBlurNotifications > 0,
+            `${this.#mDescription}, IME should receive a blur notification`
+          );
+          ok(
+            !this.#mTIPWrapper.IMEHasFocus,
+            `${this.#mDescription}, IME shouldn't have focus right now`
+          );
+        }
+      } else {
+        ok(true, `${this.#mDescription}, focus event should be fired`);
+      }
+    } else {
+      is(
+        this.#mTIPWrapper.numberOfFocusNotifications,
+        0,
+        `${
+          this.#mDescription
+        }, IME shouldn't receive a focus notification at testing non-focusable element`
+      );
+      is(
+        this.#mTIPWrapper.numberOfBlurNotifications,
+        0,
+        `${
+          this.#mDescription
+        }, IME shouldn't receive a blur notification at testing non-focusable element`
+      );
+    }
+
+    is(
+      this.#mWindowUtils.IMEStatus,
+      aExpectedData.enabledValue,
+      `${this.#mDescription}, wrong enabled state`
+    );
+    if (
+      this.#mTest.expectedInputElementType &&
+      aExpectedData.designModeValue != "on"
+    ) {
+      is(
+        this.#mWindowUtils.focusedInputType,
+        this.#mTest.expectedInputElementType,
+        `${this.#mDescription}, wrong input type`
+      );
+    } else if (aExpectedData.designModeValue == "on") {
+      is(
+        this.#mWindowUtils.focusedInputType,
+        "",
+        `${this.#mDescription}, wrong input type`
+      );
+    }
+  }
+
+  destroy() {
+    this.#mCreatedElement?.remove();
+    this.#mCreatedElementForPreviousFocusedElement?.remove();
+    this.#mTIPWrapper?.clearFocusBlurNotifications();
+    this.#mTIPWrapper = null;
+  }
+
+  /**
+   * Open/Close state test check
+   * Note that these tests are not run now.
+   * If these tests should run between `run` and `cleanUp` call of the above
+   * tests.
+   */
+  canTestOpenCloseState(aExpectedData) {
+    return (
+      IsIMEOpenStateSupported() &&
+      this.#mWindowUtils.IMEStatus ==
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED &&
+      aExpectedData.enabledValue ==
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED
+    );
+  }
+  async prepareToRunOpenCloseTest(aContainer) {
+    const doc = aContainer.ownerDocument;
+    this.#mCreatedElementForPreviousFocusedElement?.remove();
+    this.#mCreatedElementForPreviousFocusedElement = doc.createElement("input");
+    this.#mCreatedElementForPreviousFocusedElement.setAttribute("type", "text");
+    aContainer.appendChild(this.#mCreatedElementForPreviousFocusedElement);
+
+    this.#mContainerIsEditable = nodeIsEditable(aContainer);
+    this.#mCreatedElement = this.#mTest.createElement(doc);
+    const waitForLoadIfIFrame = new Promise(resolve => {
+      if (this.#mCreatedElement.tagName == "IFRAME") {
+        this.#mCreatedElement.addEventListener("load", resolve, {
+          capture: true,
+          once: true,
+        });
+      } else {
+        resolve();
+      }
+    });
+    aContainer.appendChild(this.#mCreatedElement);
+    await waitForLoadIfIFrame;
+    this.#mElementToSetFocus = this.#mCreatedElement.contentDocument
+      ? this.#mCreatedElement.contentDocument.documentElement
+      : this.#mCreatedElement;
+
+    this.#mCreatedElementForPreviousFocusedElement.focus();
+
+    return {};
+  }
+  prepareToCheckOpenCloseTest(aPreviousOpenState, aExpectedData) {
+    info(`Starting ${this.#mDescription} (open/close state check)...`);
+    this.#mWindowUtils.IMEIsOpen = aPreviousOpenState;
+    aExpectedData.defaultOpenState = this.#mWindowUtils.IMEIsOpen;
+  }
+  async runOpenCloseTest() {
+    return this.run();
+  }
+  checkOpenCloseTest(aExpectedData) {
+    const expectedOpenState =
+      this.#mTest.expectedOpenState != undefined
+        ? this.#mTest.expectedOpenState
+        : aExpectedData.defaultOpenState;
+    is(
+      this.#mWindowUtils.IMEIsOpen,
+      expectedOpenState,
+      `${this.#mDescription}, IME should ${
+        expectedOpenState != aExpectedData.defaultOpenState ? "become" : "keep"
+      } ${expectedOpenState ? "open" : "closed"}`
+    );
+  }
+
+  /**
+   * Utility methods for defining kIMEStateTestList.
+   */
+
+  /**
+   * @param {Element} aElement
+   */
+  static #elementIsConnectedAndNotInDesignMode(aElement) {
+    return aElement.isConnected && !nodeIsInDesignMode(aElement);
+  }
+
+  /**
+   * @param {Element} aElementContainer
+   * @param {bool} aElementIsEditingHost
+   */
+  static #elementIsFocusableIfEditingHost(
+    aElementContainer,
+    aElementIsEditingHost
+  ) {
+    return !nodeIsEditable(aElementContainer) && aElementIsEditingHost;
+  }
+
+  static #IMEStateEnabledAlways() {
+    return SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED;
+  }
+
+  /**
+   * @param {Element} aElement
+   * @param {bool} aElementIsEditingHost
+   */
+  static #IMEStateEnabledIfEditable(aElement, aElementIsEditingHost) {
+    return nodeIsEditable(aElement) || aElementIsEditingHost
+      ? SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED
+      : SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED;
+  }
+
+  /**
+   * @param {Element} aElement
+   */
+  static #IMEStateEnabledIfInDesignMode(aElement) {
+    return IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode(
+      aElement
+    )
+      ? SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED
+      : SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED;
+  }
+
+  /**
+   * @param {Element} aElement
+   */
+  static #IMEStatePasswordIfNotInDesignMode(aElement) {
+    return IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode(
+      aElement
+    )
+      ? SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_PASSWORD
+      : SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED;
+  }
+
+  /**
+   * @param {Element} aElement
+   */
+  static #elementIsConnectedAndNotEditable(aElement) {
+    return aElement.isConnected && !nodeIsEditable(aElement);
+  }
+
+  /**
+   * @param {Element} aElementContainer
+   */
+  static #focusEventIsExpectedUnlessEditableChild(aElementContainer) {
+    return !nodeIsEditable(aElementContainer);
+  }
+
+  // Form controls except text editable elements are "disable" in normal
+  // condition, however, if they are editable, they are "enabled".
+  // XXX Probably there are some bugs: If the form controls editable, they
+  //     shouldn't be focusable.
+  #resolveTest(aTest, aContainer) {
+    const isFocusable = aTest.isFocusable(
+      aContainer,
+      aTest.isNewElementEditingHost
+    );
+    return {
+      // Description of the new element
+      description: aTest.description,
+      // Create element to check IME state
+      createElement: aTest.createElement,
+      // Whether the new element is an editing host if container is not editable
+      isNewElementEditingHost: aTest.isNewElementEditingHost,
+      // If the test wants to move focus into an element in UA widget, define
+      // this and set focus in it.
+      setFocusIntoUAWidget: aTest.setFocusIntoUAWidget,
+      // Whether the element is focusable or not
+      isFocusable,
+      // Whether focus events are fired on the element if it's focusable
+      focusEventIsExpected:
+        isFocusable &&
+        aTest.focusEventIsExpected(aContainer, aTest.isNewElementEditingHost),
+      // Expected IME enabled state when the element has focus
+      expectedEnabledValue: aTest.expectedEnabledValue(
+        aContainer,
+        aTest.isNewElementEditingHost
+      ),
+      // Expected IME open state when the element gets focus
+      // "undefined" means that IME open state should not be changed
+      expectedOpenState: aTest.expectedOpenState,
+      // Expected type of input element if it's an <input>
+      expectedInputElementType: aTest.expectedInputElementType,
+    };
+  }
+  static #sTestList = [
+    {
+      description: "input[type=text]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "text");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedInputElementType: "text",
+    },
+    {
+      description: "input[type=text][readonly]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "text");
+        element.setAttribute("readonly", "");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+    },
+    {
+      description: "input[type=password]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "password");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStatePasswordIfNotInDesignMode,
+      expectedInputElementType: "password",
+    },
+    {
+      description: "input[type=password][readonly]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "password");
+        element.setAttribute("readonly", "");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+    },
+    {
+      description: "input[type=checkbox]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "checkbox");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected:
+        IMEStateOnFocusMoveTester.#focusEventIsExpectedUnlessEditableChild,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+    {
+      description: "input[type=radio]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "radio");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected:
+        IMEStateOnFocusMoveTester.#focusEventIsExpectedUnlessEditableChild,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+    {
+      description: "input[type=submit]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "submit");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+    {
+      description: "input[type=reset]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "reset");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+    {
+      description: "input[type=file]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "file");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected:
+        IMEStateOnFocusMoveTester.#focusEventIsExpectedUnlessEditableChild,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+    {
+      description: "input[type=button]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "button");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+    {
+      description: "input[type=image]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "image");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+    {
+      description: "input[type=url]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "url");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedInputElementType: "url",
+    },
+    {
+      description: "input[type=email]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "email");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedInputElementType: "email",
+    },
+    {
+      description: "input[type=search]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "search");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedInputElementType: "search",
+    },
+    {
+      description: "input[type=tel]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "tel");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedInputElementType: "tel",
+    },
+    {
+      description: "input[type=number]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "number");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedInputElementType: "number",
+    },
+    {
+      description: "input[type=date]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "date");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+      expectedInputElementType: "date",
+    },
+    {
+      description: "input[type=datetime-local]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "datetime-local");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+      expectedInputElementType: "datetime-local",
+    },
+    {
+      description: "input[type=time]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "time");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+      expectedInputElementType: "time",
+    },
+    // TODO(bug 1283382, bug 1283382): month and week
+
+    // form controls
+    {
+      description: "button",
+      createElement: aDocument => aDocument.createElement("button"),
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+    {
+      description: "textarea",
+      createElement: aDocument => aDocument.createElement("textarea"),
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: "textarea[readonly]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("textarea");
+        element.setAttribute("readonly", "");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+    },
+    {
+      description: "select (dropdown list)",
+      createElement: aDocument => {
+        const select = aDocument.createElement("select");
+        const option1 = aDocument.createElement("option");
+        option1.textContent = "abc";
+        const option2 = aDocument.createElement("option");
+        option2.textContent = "def";
+        const option3 = aDocument.createElement("option");
+        option3.textContent = "ghi";
+        select.appendChild(option1);
+        select.appendChild(option2);
+        select.appendChild(option3);
+        return select;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected:
+        IMEStateOnFocusMoveTester.#focusEventIsExpectedUnlessEditableChild,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+    {
+      description: "select (list box)",
+      createElement: aDocument => {
+        const select = aDocument.createElement("select");
+        select.setAttribute("multiple", "multiple");
+        const option1 = aDocument.createElement("option");
+        option1.textContent = "abc";
+        const option2 = aDocument.createElement("option");
+        option2.textContent = "def";
+        const option3 = aDocument.createElement("option");
+        option3.textContent = "ghi";
+        select.appendChild(option1);
+        select.appendChild(option2);
+        select.appendChild(option3);
+        return select;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected:
+        IMEStateOnFocusMoveTester.#focusEventIsExpectedUnlessEditableChild,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+
+    // a element
+    {
+      id: "a_href",
+      description: "a[href]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("a");
+        element.setAttribute("href", "about:blank");
+        return element;
+      },
+      isFocusable: IMEStateOnFocusMoveTester.#elementIsConnectedAndNotEditable,
+      focusEventIsExpected:
+        IMEStateOnFocusMoveTester.#focusEventIsExpectedUnlessEditableChild,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+
+    // audio element
+    {
+      description: "audio[controls]",
+      createElement: aDocument => {
+        const element = aDocument.createElement("audio");
+        element.setAttribute("controls", "");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+    {
+      description: "playButton in audio",
+      createElement: aDocument => {
+        const element = aDocument.createElement("audio");
+        element.setAttribute("controls", "");
+        return element;
+      },
+      setFocusIntoUAWidget: aElement =>
+        SpecialPowers.wrap(aElement)
+          .openOrClosedShadowRoot.getElementById("playButton")
+          .focus(),
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+    },
+    {
+      description: "scrubber in audio",
+      createElement: aDocument => {
+        const element = aDocument.createElement("audio");
+        element.setAttribute("controls", "");
+        return element;
+      },
+      setFocusIntoUAWidget: aElement =>
+        SpecialPowers.wrap(aElement)
+          .openOrClosedShadowRoot.getElementById("scrubber")
+          .focus(),
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+    },
+    {
+      description: "muteButton in audio",
+      createElement: aDocument => {
+        const element = aDocument.createElement("audio");
+        element.setAttribute("controls", "");
+        return element;
+      },
+      setFocusIntoUAWidget: aElement =>
+        SpecialPowers.wrap(aElement)
+          .openOrClosedShadowRoot.getElementById("muteButton")
+          .focus(),
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+    },
+    {
+      description: "volumeControl in audio",
+      createElement: aDocument => {
+        const element = aDocument.createElement("audio");
+        element.setAttribute("controls", "");
+        return element;
+      },
+      setFocusIntoUAWidget: aElement =>
+        SpecialPowers.wrap(aElement)
+          .openOrClosedShadowRoot.getElementById("volumeControl")
+          .focus(),
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+    },
+
+    // video element
+    {
+      description: "video",
+      createElement: aDocument => {
+        const element = aDocument.createElement("video");
+        element.setAttribute("controls", "");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfEditable,
+    },
+    {
+      description: "playButton in video",
+      createElement: aDocument => {
+        const element = aDocument.createElement("video");
+        element.setAttribute("controls", "");
+        return element;
+      },
+      setFocusIntoUAWidget: aElement =>
+        SpecialPowers.wrap(aElement)
+          .openOrClosedShadowRoot.getElementById("playButton")
+          .focus(),
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+    },
+    {
+      description: "scrubber in video",
+      createElement: aDocument => {
+        const element = aDocument.createElement("video");
+        element.setAttribute("controls", "");
+        return element;
+      },
+      setFocusIntoUAWidget: aElement =>
+        SpecialPowers.wrap(aElement)
+          .openOrClosedShadowRoot.getElementById("scrubber")
+          .focus(),
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+    },
+    {
+      description: "muteButton in video",
+      createElement: aDocument => {
+        const element = aDocument.createElement("video");
+        element.setAttribute("controls", "");
+        return element;
+      },
+      setFocusIntoUAWidget: aElement =>
+        SpecialPowers.wrap(aElement)
+          .openOrClosedShadowRoot.getElementById("muteButton")
+          .focus(),
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+    },
+    {
+      description: "volumeControl in video",
+      createElement: aDocument => {
+        const element = aDocument.createElement("video");
+        element.setAttribute("controls", "");
+        return element;
+      },
+      setFocusIntoUAWidget: aElement =>
+        SpecialPowers.wrap(aElement)
+          .openOrClosedShadowRoot.getElementById("volumeControl")
+          .focus(),
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStateEnabledIfInDesignMode,
+    },
+
+    // ime-mode
+    {
+      description: 'input[type=text][style="ime-mode: auto;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "text");
+        element.setAttribute("style", "ime-mode: auto;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=text][style="ime-mode: normal;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "text");
+        element.setAttribute("style", "ime-mode: normal;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=text][style="ime-mode: active;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "text");
+        element.setAttribute("style", "ime-mode: active;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedOpenState: true,
+    },
+    {
+      description: 'input[type=text][style="ime-mode: inactive;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "text");
+        element.setAttribute("style", "ime-mode: inactive;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedOpenState: false,
+    },
+    {
+      description: 'input[type=text][style="ime-mode: disabled;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "text");
+        element.setAttribute("style", "ime-mode: disabled;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStatePasswordIfNotInDesignMode,
+    },
+
+    {
+      description: 'input[type=url][style="ime-mode: auto;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "url");
+        element.setAttribute("style", "ime-mode: auto;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=url][style="ime-mode: normal;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "url");
+        element.setAttribute("style", "ime-mode: normal;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=url][style="ime-mode: active;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "url");
+        element.setAttribute("style", "ime-mode: active;");
+        return element;
+      },
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedOpenState: true,
+    },
+    {
+      description: 'input[type=url][style="ime-mode: inactive;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "url");
+        element.setAttribute("style", "ime-mode: inactive;");
+        return element;
+      },
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedOpenState: false,
+    },
+    {
+      description: 'input[type=url][style="ime-mode: disabled;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "url");
+        element.setAttribute("style", "ime-mode: disabled;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStatePasswordIfNotInDesignMode,
+    },
+
+    {
+      description: 'input[type=email][style="ime-mode: auto;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "email");
+        element.setAttribute("style", "ime-mode: auto;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=email][style="ime-mode: normal;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "email");
+        element.setAttribute("style", "ime-mode: normal;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=email][style="ime-mode: active;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "email");
+        element.setAttribute("style", "ime-mode: active;");
+        return element;
+      },
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedOpenState: true,
+    },
+    {
+      description: 'input[type=email][style="ime-mode: inactive;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "email");
+        element.setAttribute("style", "ime-mode: inactive;");
+        return element;
+      },
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedOpenState: false,
+    },
+    {
+      description: 'input[type=email][style="ime-mode: disabled;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "email");
+        element.setAttribute("style", "ime-mode: disabled;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStatePasswordIfNotInDesignMode,
+    },
+
+    {
+      description: 'input[type=search][style="ime-mode: auto;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "search");
+        element.setAttribute("style", "ime-mode: auto;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=search][style="ime-mode: normal;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "search");
+        element.setAttribute("style", "ime-mode: normal;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=search][style="ime-mode: active;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "search");
+        element.setAttribute("style", "ime-mode: active;");
+        return element;
+      },
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedOpenState: true,
+    },
+    {
+      description: 'input[type=search][style="ime-mode: inactive;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "search");
+        element.setAttribute("style", "ime-mode: inactive;");
+        return element;
+      },
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedOpenState: false,
+    },
+    {
+      description: 'input[type=search][style="ime-mode: disabled;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "search");
+        element.setAttribute("style", "ime-mode: disabled;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStatePasswordIfNotInDesignMode,
+    },
+
+    {
+      description: 'input[type=tel][style="ime-mode: auto;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "tel");
+        element.setAttribute("style", "ime-mode: auto;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=tel][style="ime-mode: normal;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "tel");
+        element.setAttribute("style", "ime-mode: normal;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=tel][style="ime-mode: active;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "tel");
+        element.setAttribute("style", "ime-mode: active;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedOpenState: true,
+    },
+    {
+      description: 'input[type=tel][style="ime-mode: inactive;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "tel");
+        element.setAttribute("style", "ime-mode: inactive;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedOpenState: false,
+    },
+    {
+      description: 'input[type=tel][style="ime-mode: disabled;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "tel");
+        element.setAttribute("style", "ime-mode: disabled;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStatePasswordIfNotInDesignMode,
+    },
+
+    {
+      description: 'input[type=number][style="ime-mode: auto;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "number");
+        element.setAttribute("style", "ime-mode: auto;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=number][style="ime-mode: normal;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "number");
+        element.setAttribute("style", "ime-mode: normal;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=number][style="ime-mode: active;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "number");
+        element.setAttribute("style", "ime-mode: active;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedOpenState: true,
+    },
+    {
+      description: 'input[type=number][style="ime-mode: inactive;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "number");
+        element.setAttribute("style", "ime-mode: inactive;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedOpenState: false,
+    },
+    {
+      description: 'input[type=number][style="ime-mode: disabled;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "number");
+        element.setAttribute("style", "ime-mode: disabled;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStatePasswordIfNotInDesignMode,
+    },
+
+    {
+      description: 'input[type=password][style="ime-mode: auto;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "password");
+        element.setAttribute("style", "ime-mode: auto;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStatePasswordIfNotInDesignMode,
+    },
+    {
+      description: 'input[type=password][style="ime-mode: normal;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "password");
+        element.setAttribute("style", "ime-mode: normal;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'input[type=password][style="ime-mode: active;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "password");
+        element.setAttribute("style", "ime-mode: active;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedOpenState: true,
+    },
+    {
+      description: 'input[type=password][style="ime-mode: inactive;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "password");
+        element.setAttribute("style", "ime-mode: inactive;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedOpenState: false,
+    },
+    {
+      description: 'input[type=password][style="ime-mode: disabled;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("input");
+        element.setAttribute("type", "password");
+        element.setAttribute("style", "ime-mode: disabled;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStatePasswordIfNotInDesignMode,
+    },
+    {
+      description: 'textarea[style="ime-mode: auto;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("textarea");
+        element.setAttribute("style", "ime-mode: auto;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'textarea[style="ime-mode: normal;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("textarea");
+        element.setAttribute("style", "ime-mode: normal;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: 'textarea[style="ime-mode: active;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("textarea");
+        element.setAttribute("style", "ime-mode: active;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedOpenState: true,
+    },
+    {
+      description: 'textarea[style="ime-mode: inactive;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("textarea");
+        element.setAttribute("style", "ime-mode: inactive;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+      expectedOpenState: false,
+    },
+    {
+      description: 'textarea[style="ime-mode: disabled;"]',
+      createElement: aDocument => {
+        const element = aDocument.createElement("textarea");
+        element.setAttribute("style", "ime-mode: disabled;");
+        return element;
+      },
+      isFocusable:
+        IMEStateOnFocusMoveTester.#elementIsConnectedAndNotInDesignMode,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue:
+        IMEStateOnFocusMoveTester.#IMEStatePasswordIfNotInDesignMode,
+    },
+
+    // HTML editors
+    {
+      description: 'div[contenteditable="true"]',
+      createElement: aDocument => {
+        const div = aDocument.createElement("div");
+        div.setAttribute("contenteditable", "");
+        return div;
+      },
+      isNewElementEditingHost: true,
+      isFocusable: IMEStateOnFocusMoveTester.#elementIsFocusableIfEditingHost,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+    {
+      description: "designMode editor",
+      createElement: aDocument => {
+        const iframe = aDocument.createElement("iframe");
+        iframe.srcdoc = "<!doctype html><html><body></body></html>";
+        iframe.addEventListener(
+          "load",
+          () => (iframe.contentDocument.designMode = "on"),
+          { capture: true, once: true }
+        );
+        return iframe;
+      },
+      isFocusable: () => true,
+      focusEventIsExpected: () => true,
+      expectedEnabledValue: IMEStateOnFocusMoveTester.#IMEStateEnabledAlways,
+    },
+  ];
+
+  static get numberOfTests() {
+    return IMEStateOnFocusMoveTester.#sTestList.length;
+  }
+}
diff --git a/widget/tests/file_test_ime_state_on_input_type_change.js b/widget/tests/file_test_ime_state_on_input_type_change.js
new file mode 100644
index 0000000000..38c139d6a2
--- /dev/null
+++ b/widget/tests/file_test_ime_state_on_input_type_change.js
@@ -0,0 +1,315 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from file_ime_state_test_helper.js */
+
+class IMEStateOnInputTypeChangeTester {
+  static #sInputElementList = [
+    {
+      type: "",
+      textControl: true,
+    },
+    {
+      type: "text",
+      textControl: true,
+    },
+    {
+      type: "text",
+      readonly: true,
+      textControl: true,
+    },
+    {
+      type: "password",
+      textControl: true,
+    },
+    {
+      type: "password",
+      readonly: true,
+      textControl: true,
+    },
+    {
+      type: "checkbox",
+      buttonControl: true,
+    },
+    {
+      type: "radio",
+      buttonControl: true,
+    },
+    {
+      type: "submit",
+      buttonControl: true,
+    },
+    {
+      type: "reset",
+      buttonControl: true,
+    },
+    {
+      type: "file",
+      buttonControl: true,
+    },
+    {
+      type: "button",
+      buttonControl: true,
+    },
+    {
+      type: "image",
+      alt: "image",
+      buttonControl: true,
+    },
+    {
+      type: "url",
+      textControl: true,
+    },
+    {
+      type: "email",
+      textControl: true,
+    },
+    {
+      type: "search",
+      textControl: true,
+    },
+    {
+      type: "tel",
+      textControl: true,
+    },
+    {
+      type: "number",
+      textControl: true,
+    },
+    {
+      type: "date",
+      dateTimeControl: true,
+    },
+    {
+      type: "datetime-local",
+      dateTimeControl: true,
+    },
+    {
+      type: "time",
+      dateTimeControl: true,
+    },
+    {
+      type: "range",
+      buttonControl: true,
+    },
+    {
+      type: "color",
+      buttonControl: true,
+    },
+    // TODO(bug 1283382, bug 1283382): month and week
+  ];
+
+  static get numberOfTests() {
+    return IMEStateOnInputTypeChangeTester.#sInputElementList.length;
+  }
+
+  /**
+   * @param {HTMLInputElement} aInputElement The input element.
+   * @returns {number} Expected IME state when aInputElement has focus.
+   */
+  static #getExpectedIMEEnabledState(aInputElement) {
+    if (aInputElement.readonly) {
+      return SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED;
+    }
+    switch (aInputElement.type) {
+      case "text":
+      case "url":
+      case "email":
+      case "search":
+      case "tel":
+      case "number":
+        return aInputElement.style.imeMode == "disabled"
+          ? SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_PASSWORD
+          : SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED;
+
+      case "password":
+        return aInputElement.style.imeMode == "" ||
+          aInputElement.style.imeMode == "auto" ||
+          aInputElement.style.imeMode == "disabled"
+          ? SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_PASSWORD
+          : SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED;
+
+      default:
+        return SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED;
+    }
+  }
+
+  static #getDescription(aInputElement) {
+    let desc = "<input";
+    if (aInputElement.getAttribute("type")) {
+      desc += ` type="${aInputElement.getAttribute("type")}"`;
+    }
+    if (aInputElement.readonly) {
+      desc += " readonly";
+    }
+    if (aInputElement.getAttribute("style")) {
+      desc += ` style="ime-mode: ${aInputElement.style.imeMode}"`;
+    }
+    return desc + ">";
+  }
+
+  // Only runner fields
+  #mSrcTypeIndex;
+  #mType;
+  #mInputElement;
+  #mNewType;
+  #mWindow;
+
+  // Only checker fields
+  #mWindowUtils;
+  #mTIPWrapper;
+
+  /**
+   * @param {number} aSrcTypeIndex `type` attribute value index in #sInputElementList
+   */
+  constructor(aSrcTypeIndex) {
+    this.#mSrcTypeIndex = aSrcTypeIndex;
+    this.#mType =
+      IMEStateOnInputTypeChangeTester.#sInputElementList[this.#mSrcTypeIndex];
+  }
+
+  clear() {
+    this.#mInputElement?.remove();
+    this.#mTIPWrapper?.clearFocusBlurNotifications();
+    this.#mTIPWrapper = null;
+  }
+
+  #flushPendingIMENotifications() {
+    return new Promise(resolve =>
+      this.#mWindow.requestAnimationFrame(() =>
+        this.#mWindow.requestAnimationFrame(resolve)
+      )
+    );
+  }
+
+  /**
+   * @param {number} aDestTypeIndex New type index.
+   * @param {Window} aWindow The window running tests.
+   * @param {Element} aContainer The element which should have new <input>.
+   * @param {undefined|string} aIMEModeValue [optional] ime-mode value if you want to specify.
+   * @returns {object|bool} Expected data before running tests.  If the test should not run, returns false.
+   */
+  async prepareToRun(aDestTypeIndex, aWindow, aContainer, aIMEModeValue) {
+    this.#mWindow = aWindow;
+
+    if (aContainer.ownerDocument.activeElement) {
+      aContainer.ownerDocument.activeElement.blur();
+      await this.#flushPendingIMENotifications();
+    }
+    if (this.#mInputElement?.isConnected) {
+      this.#mInputElement.remove();
+    }
+    this.#mInputElement = null;
+
+    this.#mNewType =
+      IMEStateOnInputTypeChangeTester.#sInputElementList[aDestTypeIndex];
+    if (
+      aDestTypeIndex == this.#mSrcTypeIndex ||
+      this.#mNewType.readonly ||
+      (!this.#mType.textControl && !this.#mNewType.textControl)
+    ) {
+      return false;
+    }
+    this.#mInputElement = aContainer.ownerDocument.createElement("input");
+    if (this.#mType.type != "") {
+      this.#mInputElement.setAttribute("type", this.#mType.type);
+    }
+    if (this.#mType.readonly) {
+      this.#mInputElement.setAttribute("readonly", "");
+    }
+    if (aIMEModeValue && aIMEModeValue !== "") {
+      this.#mInputElement.setAttribute("style", `ime-mode: ${aIMEModeValue}`);
+    }
+    if (this.#mType.alt) {
+      this.#mInputElement.setAttribute("alt", this.#mType.alt);
+    }
+    const waitForFocus = new Promise(resolve =>
+      this.#mInputElement.addEventListener("focus", resolve, { once: true })
+    );
+    aContainer.appendChild(this.#mInputElement);
+    this.#mInputElement.focus();
+    await waitForFocus;
+
+    await this.#flushPendingIMENotifications();
+
+    const expectedIMEState =
+      IMEStateOnInputTypeChangeTester.#getExpectedIMEEnabledState(
+        this.#mInputElement
+      );
+    return {
+      description: IMEStateOnInputTypeChangeTester.#getDescription(
+        this.#mInputElement
+      ),
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  /**
+   * @param {object} aExpectedData The expected data which was returned by prepareToRun().
+   * @param {TIPWrapper} aTIPWrapper TIP wrapper in aWindow.
+   * @param {Window} aWindow [optional] The window object of which you want to check IME state.
+   */
+  checkBeforeRun(aExpectedData, aTIPWrapper, aWindow = window) {
+    this.#mWindowUtils = SpecialPowers.wrap(aWindow).windowUtils;
+    this.#mTIPWrapper = aTIPWrapper;
+    const description = `IMEStateOnInputTypeChangeTester(${aExpectedData.description})`;
+    is(
+      this.#mWindowUtils.IMEStatus,
+      aExpectedData.expectedIMEState,
+      `${description}: IME state should be set to expected value before running test`
+    );
+    is(
+      this.#mTIPWrapper.IMEHasFocus,
+      aExpectedData.expectedIMEFocus,
+      `${description}: IME state should ${
+        aExpectedData.expectedIMEFocus ? "" : "not"
+      }have focus before running test`
+    );
+  }
+
+  /**
+   * @returns {object} The expected results.
+   */
+  async run() {
+    if (this.#mNewType.type == "") {
+      this.#mInputElement.removeAttribute("type");
+    } else {
+      this.#mInputElement.setAttribute("type", this.#mNewType.type);
+    }
+
+    await this.#flushPendingIMENotifications();
+
+    const expectedIMEState =
+      IMEStateOnInputTypeChangeTester.#getExpectedIMEEnabledState(
+        this.#mInputElement
+      );
+    return {
+      newType: this.#mNewType.type,
+      expectedIMEState,
+      expectedIMEFocus:
+        expectedIMEState !=
+        SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    };
+  }
+
+  checkResult(aExpectedDataBeforeRun, aExpectedData) {
+    const description = `IMEStateOnInputTypeChangeTester(${
+      aExpectedDataBeforeRun.description
+    } -> type="${aExpectedData.newType || ""}")`;
+    is(
+      this.#mWindowUtils.IMEStatus,
+      aExpectedData.expectedIMEState,
+      `${description}: IME state should be set to expected value`
+    );
+    is(
+      this.#mTIPWrapper.IMEHasFocus,
+      aExpectedData.expectedIMEFocus,
+      `${description}: IME state should have focus`
+    );
+  }
+}
diff --git a/widget/tests/file_test_ime_state_on_readonly_change.js b/widget/tests/file_test_ime_state_on_readonly_change.js
new file mode 100644
index 0000000000..af21f538ba
--- /dev/null
+++ b/widget/tests/file_test_ime_state_on_readonly_change.js
@@ -0,0 +1,242 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/* import-globals-from file_ime_state_test_helper.js */
+
+class IMEStateOnReadonlyChangeTester {
+  static #sTextControlTypes = [
+    {
+      description: "<input>",
+      createElement: aDoc => aDoc.createElement("input"),
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+    },
+    {
+      description: `<input type="text">`,
+      createElement: aDoc => {
+        const input = aDoc.createElement("input");
+        input.setAttribute("type", "text");
+        return input;
+      },
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+    },
+    {
+      description: `<input type="password">`,
+      createElement: aDoc => {
+        const input = aDoc.createElement("input");
+        input.setAttribute("type", "password");
+        return input;
+      },
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_PASSWORD,
+    },
+    {
+      description: `<input type="url">`,
+      createElement: aDoc => {
+        const input = aDoc.createElement("input");
+        input.setAttribute("type", "url");
+        return input;
+      },
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+    },
+    {
+      description: `<input type="email">`,
+      createElement: aDoc => {
+        const input = aDoc.createElement("input");
+        input.setAttribute("type", "email");
+        return input;
+      },
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+    },
+    {
+      description: `<input type="search">`,
+      createElement: aDoc => {
+        const input = aDoc.createElement("input");
+        input.setAttribute("type", "search");
+        return input;
+      },
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+    },
+    {
+      description: `<input type="tel">`,
+      createElement: aDoc => {
+        const input = aDoc.createElement("input");
+        input.setAttribute("type", "tel");
+        return input;
+      },
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+    },
+    {
+      description: `<input type="number">`,
+      createElement: aDoc => {
+        const input = aDoc.createElement("input");
+        input.setAttribute("type", "number");
+        return input;
+      },
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+    },
+    {
+      description: `<textarea></textarea>`,
+      createElement: aDoc => aDoc.createElement("textarea"),
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+    },
+  ];
+
+  static get numberOfTextControlTypes() {
+    return IMEStateOnReadonlyChangeTester.#sTextControlTypes.length;
+  }
+
+  // Only runner fields
+  #mTextControl;
+  #mTextControlElement;
+  #mWindow;
+
+  // Only checker fields
+  #mWindowUtils;
+  #mTIPWrapper;
+
+  clear() {
+    this.#mTextControlElement?.remove();
+    this.#mTIPWrapper?.clearFocusBlurNotifications();
+    this.#mTIPWrapper = null;
+  }
+
+  #flushPendingIMENotifications() {
+    return new Promise(resolve =>
+      this.#mWindow.requestAnimationFrame(() =>
+        this.#mWindow.requestAnimationFrame(resolve)
+      )
+    );
+  }
+
+  /**
+   * @param {number} aIndex The index of text control types.
+   * @param {Window} aWindow The window running tests.
+   * @param {Element} aContainer The element which should have new <input> or <textarea>.
+   * @returns {object} Expected data before running tests.
+   */
+  async prepareToRun(aIndex, aWindow, aContainer) {
+    this.#mWindow = aWindow;
+    this.#mTextControl =
+      IMEStateOnReadonlyChangeTester.#sTextControlTypes[aIndex];
+
+    if (aContainer.ownerDocument.activeElement) {
+      aContainer.ownerDocument.activeElement.blur();
+      await this.#flushPendingIMENotifications();
+    }
+    if (this.#mTextControlElement?.isConnected) {
+      this.#mTextControlElement.remove();
+    }
+    this.#mTextControlElement = this.#mTextControl.createElement(
+      aContainer.ownerDocument
+    );
+
+    const waitForFocus = new Promise(resolve =>
+      this.#mTextControlElement.addEventListener("focus", resolve, {
+        once: true,
+      })
+    );
+    aContainer.appendChild(this.#mTextControlElement);
+    this.#mTextControlElement.focus();
+    await waitForFocus;
+
+    await this.#flushPendingIMENotifications();
+
+    return {
+      description: this.#mTextControl.description,
+      expectedIMEState: this.#mTextControl.expectedIMEState,
+      expectedIMEFocus: true,
+    };
+  }
+
+  /**
+   * @param {object} aExpectedData The expected data which was returned by prepareToRun().
+   * @param {TIPWrapper} aTIPWrapper TIP wrapper in aWindow.
+   * @param {Window} aWindow [optional] The window object of which you want to check IME state.
+   */
+  checkBeforeRun(aExpectedData, aTIPWrapper, aWindow = window) {
+    this.#mWindowUtils = SpecialPowers.wrap(aWindow).windowUtils;
+    this.#mTIPWrapper = aTIPWrapper;
+    const description = `IMEStateOnReadonlyChangeTester(${aExpectedData.description})`;
+    is(
+      this.#mWindowUtils.IMEStatus,
+      aExpectedData.expectedIMEState,
+      `${description}: IME state should be set to expected value before setting readonly attribute`
+    );
+    is(
+      this.#mTIPWrapper.IMEHasFocus,
+      aExpectedData.expectedIMEFocus,
+      `${description}: IME state should ${
+        aExpectedData.expectedIMEFocus ? "" : "not"
+      } have focus before setting readonly attribute`
+    );
+  }
+
+  /**
+   * @returns {object} Expected result.
+   */
+  async runToMakeTextControlReadonly() {
+    this.#mTextControlElement.setAttribute("readonly", "");
+
+    await this.#flushPendingIMENotifications();
+
+    return {
+      description: this.#mTextControl.description,
+      expectedIMEState: SpecialPowers.Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      expectedIMEFocus: false,
+    };
+  }
+
+  /**
+   * @param {object} aExpectedData Expected result which is returned by runToMakeTextControlReadonly().
+   */
+  checkResultOfMakingTextControlReadonly(aExpectedData) {
+    const description = `IMEStateOnReadonlyChangeTester(${aExpectedData.description})`;
+    is(
+      this.#mWindowUtils.IMEStatus,
+      aExpectedData.expectedIMEState,
+      `${description}: IME state should be set to expected value after setting readonly attribute`
+    );
+    is(
+      this.#mTIPWrapper.IMEHasFocus,
+      aExpectedData.expectedIMEFocus,
+      `${description}: IME state should ${
+        aExpectedData.expectedIMEFocus ? "" : "not"
+      } have focus after setting readonly attribute`
+    );
+  }
+
+  /**
+   * @returns {object} Expected result.
+   */
+  async runToMakeTextControlEditable() {
+    this.#mTextControlElement.removeAttribute("readonly");
+
+    await this.#flushPendingIMENotifications();
+
+    return {
+      description: this.#mTextControl.description,
+      expectedIMEState: this.#mTextControl.expectedIMEState,
+      expectedIMEFocus: true,
+    };
+  }
+
+  /**
+   * @param {object} aExpectedData Expected result which is returned by runToMakeTextControlEditable().
+   */
+  checkResultOfMakingTextControlEditable(aExpectedData) {
+    const description = `IMEStateOnReadonlyChangeTester(${aExpectedData.description})`;
+    is(
+      this.#mWindowUtils.IMEStatus,
+      aExpectedData.expectedIMEState,
+      `${description}: IME state should be set to expected value after removing readonly attribute`
+    );
+    is(
+      this.#mTIPWrapper.IMEHasFocus,
+      aExpectedData.expectedIMEFocus,
+      `${description}: IME state should ${
+        aExpectedData.expectedIMEFocus ? "" : "not"
+      } have focus after removing readonly attribute`
+    );
+  }
+}
diff --git a/widget/tests/gtest/MockWinWidget.cpp b/widget/tests/gtest/MockWinWidget.cpp
new file mode 100644
index 0000000000..ed7850076f
--- /dev/null
+++ b/widget/tests/gtest/MockWinWidget.cpp
@@ -0,0 +1,77 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "MockWinWidget.h"
+
+#include "mozilla/gfx/Logging.h"
+
+NS_IMPL_ISUPPORTS_INHERITED0(MockWinWidget, nsBaseWidget)
+
+// static
+RefPtr<MockWinWidget> MockWinWidget::Create(DWORD aStyle, DWORD aExStyle,
+                                            const LayoutDeviceIntRect& aRect) {
+  RefPtr<MockWinWidget> window = new MockWinWidget;
+  if (!window->Initialize(aStyle, aExStyle, aRect)) {
+    return nullptr;
+  }
+
+  return window;
+}
+
+MockWinWidget::MockWinWidget() {}
+
+MockWinWidget::~MockWinWidget() {
+  if (mWnd) {
+    ::DestroyWindow(mWnd);
+    mWnd = 0;
+  }
+}
+
+bool MockWinWidget::Initialize(DWORD aStyle, DWORD aExStyle,
+                               const LayoutDeviceIntRect& aRect) {
+  WNDCLASSW wc;
+  const wchar_t className[] = L"MozillaMockWinWidget";
+  HMODULE hSelf = ::GetModuleHandle(nullptr);
+
+  if (!GetClassInfoW(hSelf, className, &wc)) {
+    ZeroMemory(&wc, sizeof(WNDCLASSW));
+    wc.hInstance = hSelf;
+    wc.lpfnWndProc = ::DefWindowProc;
+    wc.lpszClassName = className;
+    RegisterClassW(&wc);
+  }
+
+  mWnd = ::CreateWindowExW(aExStyle, className, className, aStyle, aRect.X(),
+                           aRect.Y(), aRect.Width(), aRect.Height(), nullptr,
+                           nullptr, hSelf, nullptr);
+  if (!mWnd) {
+    gfxCriticalNoteOnce << "GetClientRect failed " << ::GetLastError();
+    return false;
+  }
+
+  // First nccalcszie (during CreateWindow) for captioned windows is
+  // deliberately ignored so force a second one here to get the right
+  // non-client set up.
+  if (mWnd && (aStyle & WS_CAPTION)) {
+    ::SetWindowPos(mWnd, NULL, 0, 0, 0, 0,
+                   SWP_FRAMECHANGED | SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER |
+                       SWP_NOACTIVATE | SWP_NOREDRAW);
+  }
+
+  mBounds = aRect;
+  return true;
+}
+
+void MockWinWidget::NotifyOcclusionState(
+    mozilla::widget::OcclusionState aState) {
+  mCurrentState = aState;
+}
+
+nsSizeMode MockWinWidget::SizeMode() {
+  if (::IsIconic(mWnd)) {
+    return nsSizeMode_Minimized;
+  }
+  return nsSizeMode_Normal;
+}
diff --git a/widget/tests/gtest/MockWinWidget.h b/widget/tests/gtest/MockWinWidget.h
new file mode 100644
index 0000000000..891e1c942d
--- /dev/null
+++ b/widget/tests/gtest/MockWinWidget.h
@@ -0,0 +1,85 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GTEST_MockWinWidget_H
+#define GTEST_MockWinWidget_H
+
+#include <windows.h>
+
+#include "nsBaseWidget.h"
+#include "Units.h"
+
+class MockWinWidget : public nsBaseWidget {
+ public:
+  static RefPtr<MockWinWidget> Create(DWORD aStyle, DWORD aExStyle,
+                                      const LayoutDeviceIntRect& aRect);
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  void NotifyOcclusionState(mozilla::widget::OcclusionState aState) override;
+
+  void SetExpectation(mozilla::widget::OcclusionState aExpectation) {
+    mExpectation = aExpectation;
+  }
+
+  bool IsExpectingCall() const { return mExpectation != mCurrentState; }
+
+  HWND GetWnd() { return mWnd; }
+
+  nsSizeMode SizeMode() override;
+  void SetSizeMode(nsSizeMode aMode) override {}
+
+  void* GetNativeData(uint32_t aDataType) override { return nullptr; }
+
+  virtual nsresult Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                          const LayoutDeviceIntRect& aRect,
+                          InitData* aInitData = nullptr) override {
+    return NS_OK;
+  }
+  virtual nsresult Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                          const DesktopIntRect& aRect,
+                          InitData* aInitData = nullptr) override {
+    return NS_OK;
+  }
+  virtual void Show(bool aState) override {}
+  virtual bool IsVisible() const override { return true; }
+  virtual void Move(double aX, double aY) override {}
+  virtual void Resize(double aWidth, double aHeight, bool aRepaint) override {}
+  virtual void Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) override {}
+
+  virtual void Enable(bool aState) override {}
+  virtual bool IsEnabled() const override { return true; }
+  virtual void SetFocus(Raise, mozilla::dom::CallerType aCallerType) override {}
+  virtual void Invalidate(const LayoutDeviceIntRect& aRect) override {}
+  virtual nsresult SetTitle(const nsAString& title) override { return NS_OK; }
+  virtual LayoutDeviceIntPoint WidgetToScreenOffset() override {
+    return LayoutDeviceIntPoint(0, 0);
+  }
+  virtual nsresult DispatchEvent(mozilla::WidgetGUIEvent* aEvent,
+                                 nsEventStatus& aStatus) override {
+    return NS_OK;
+  }
+  virtual void SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction) override {}
+  virtual InputContext GetInputContext() override { abort(); }
+
+ private:
+  MockWinWidget();
+  ~MockWinWidget();
+
+  bool Initialize(DWORD aStyle, DWORD aExStyle,
+                  const LayoutDeviceIntRect& aRect);
+
+  HWND mWnd = 0;
+
+  mozilla::widget::OcclusionState mExpectation =
+      mozilla::widget::OcclusionState::UNKNOWN;
+  mozilla::widget::OcclusionState mCurrentState =
+      mozilla::widget::OcclusionState::UNKNOWN;
+};
+
+#endif
diff --git a/widget/tests/gtest/TestTimeConverter.cpp b/widget/tests/gtest/TestTimeConverter.cpp
new file mode 100644
index 0000000000..22cbc3f9e6
--- /dev/null
+++ b/widget/tests/gtest/TestTimeConverter.cpp
@@ -0,0 +1,265 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "mozilla/TimeStamp.h"
+#include "SystemTimeConverter.h"
+
+using mozilla::SystemTimeConverter;
+using mozilla::TimeDuration;
+using mozilla::TimeStamp;
+
+namespace {
+
+// This class provides a mock implementation of the CurrentTimeGetter template
+// type used in SystemTimeConverter. It can be constructed with a particular
+// Time and always returns that Time.
+template <typename Time>
+class MockCurrentTimeGetter {
+ public:
+  MockCurrentTimeGetter() : mTime(0) {}
+  explicit MockCurrentTimeGetter(Time aTime) : mTime(aTime) {}
+
+  // Methods needed for CurrentTimeGetter compatibility
+  Time GetCurrentTime() const { return mTime; }
+  void GetTimeAsyncForPossibleBackwardsSkew(const TimeStamp& aNow) {}
+
+ private:
+  Time mTime;
+};
+
+// This is another mock implementation of the CurrentTimeGetter template
+// type used in SystemTimeConverter, except this asserts that it will not be
+// used. i.e. it should only be used in calls to SystemTimeConverter that we
+// know will not invoke it.
+template <typename Time>
+class UnusedCurrentTimeGetter {
+ public:
+  Time GetCurrentTime() const {
+    EXPECT_TRUE(false);
+    return 0;
+  }
+
+  void GetTimeAsyncForPossibleBackwardsSkew(const TimeStamp& aNow) {
+    EXPECT_TRUE(false);
+  }
+};
+
+// This class provides a mock implementation of the TimeStampNowProvider
+// template type used in SystemTimeConverter. It also has other things in it
+// that allow the test to better control time for testing purposes.
+class MockTimeStamp {
+ public:
+  // This should generally be called at the start of every test function, as
+  // it will initialize this class's static fields to sane values. In particular
+  // it will initialize the baseline TimeStamp against which all other
+  // TimeStamps are compared.
+  static void Init() {
+    sBaseline = TimeStamp::Now();
+    sTimeStamp = sBaseline;
+  }
+
+  // Advance the timestamp returned by `MockTimeStamp::Now()`
+  static void Advance(double ms) {
+    sTimeStamp += TimeDuration::FromMilliseconds(ms);
+  }
+
+  // Returns the baseline TimeStamp, that is used as a fixed reference point
+  // in time against which other TimeStamps can be compared. This is needed
+  // because mozilla::TimeStamp itself doesn't provide any conversion to
+  // human-readable strings, and we need to convert it to a TimeDuration in
+  // order to get that. This baseline TimeStamp can be used to turn an
+  // arbitrary TimeStamp into a TimeDuration.
+  static TimeStamp Baseline() { return sBaseline; }
+
+  // This is the method needed for TimeStampNowProvider compatibility, and
+  // simulates `TimeStamp::Now()`
+  static TimeStamp Now() { return sTimeStamp; }
+
+ private:
+  static TimeStamp sTimeStamp;
+  static TimeStamp sBaseline;
+};
+
+TimeStamp MockTimeStamp::sTimeStamp;
+TimeStamp MockTimeStamp::sBaseline;
+
+// Could have platform-specific implementations of this using DWORD, guint32,
+// etc behind ifdefs. But this is sufficient for now.
+using GTestTime = uint32_t;
+using TimeConverter = SystemTimeConverter<GTestTime, MockTimeStamp>;
+
+}  // namespace
+
+// Checks the expectation that the TimeStamp `ts` is exactly `ms` milliseconds
+// after the baseline timestamp. This is a macro so gtest still gives us useful
+// line numbers for failures.
+#define EXPECT_TS(ts, ms) \
+  EXPECT_EQ((ts)-MockTimeStamp::Baseline(), TimeDuration::FromMilliseconds(ms))
+
+#define EXPECT_TS_FUZZY(ts, ms) \
+  EXPECT_DOUBLE_EQ(((ts)-MockTimeStamp::Baseline()).ToMilliseconds(), ms)
+
+TEST(TimeConverter, SanityCheck)
+{
+  MockTimeStamp::Init();
+
+  MockCurrentTimeGetter timeGetter(10);
+  UnusedCurrentTimeGetter<GTestTime> unused;
+  TimeConverter converter;
+
+  // This call sets the reference time and timestamp
+  TimeStamp ts = converter.GetTimeStampFromSystemTime(10, timeGetter);
+  EXPECT_TS(ts, 0);
+
+  // Advance "TimeStamp::Now" by 10ms, use the same event time and OS time.
+  // Since the event time is the same as before, we expect to get back the
+  // same TimeStamp as before too, despite Now() changing.
+  MockTimeStamp::Advance(10);
+  ts = converter.GetTimeStampFromSystemTime(10, unused);
+  EXPECT_TS(ts, 0);
+
+  // Now let's use an event time 20ms after the old event. This will trigger
+  // forward skew detection and resync the TimeStamp for the new event to Now().
+  ts = converter.GetTimeStampFromSystemTime(30, unused);
+  EXPECT_TS(ts, 10);
+}
+
+TEST(TimeConverter, Overflow)
+{
+  // This tests wrapping time around the max value supported in the GTestTime
+  // type and ensuring it is handled properly.
+
+  MockTimeStamp::Init();
+
+  const GTestTime max = std::numeric_limits<GTestTime>::max();
+  const GTestTime min = std::numeric_limits<GTestTime>::min();
+  double fullRange = (double)max - (double)min;
+  double wrapPeriod = fullRange + 1.0;
+
+  GTestTime almostOverflowed = max - 100;
+  GTestTime overflowed = max + 100;
+  MockCurrentTimeGetter timeGetter(almostOverflowed);
+  UnusedCurrentTimeGetter<GTestTime> unused;
+  TimeConverter converter;
+
+  // Set reference time to 100ms before the overflow point
+  TimeStamp ts =
+      converter.GetTimeStampFromSystemTime(almostOverflowed, timeGetter);
+  EXPECT_TS(ts, 0);
+
+  // Advance everything by 200ms and verify we get back a TimeStamp 200ms from
+  // the baseline despite wrapping an overflow.
+  MockTimeStamp::Advance(200);
+  ts = converter.GetTimeStampFromSystemTime(overflowed, unused);
+  EXPECT_TS(ts, 200);
+
+  // Advance by another full wraparound of the time. This loses some precision
+  // so we have to do the FUZZY match
+  MockTimeStamp::Advance(wrapPeriod);
+  ts = converter.GetTimeStampFromSystemTime(overflowed, unused);
+  EXPECT_TS_FUZZY(ts, 200.0 + wrapPeriod);
+}
+
+TEST(TimeConverter, InvertedOverflow)
+{
+  // This tests time going from near the min value of GTestTime to the max
+  // value of GTestTime
+
+  MockTimeStamp::Init();
+
+  const GTestTime max = std::numeric_limits<GTestTime>::max();
+  const GTestTime min = std::numeric_limits<GTestTime>::min();
+  double fullRange = (double)max - (double)min;
+  double wrapPeriod = fullRange + 1.0;
+
+  GTestTime nearRangeMin = min + 100;
+  GTestTime nearRangeMax = max - 100;
+  double gap = (double)nearRangeMax - (double)nearRangeMin;
+
+  MockCurrentTimeGetter timeGetter(nearRangeMin);
+  UnusedCurrentTimeGetter<GTestTime> unused;
+  TimeConverter converter;
+
+  // Set reference time to value near min numeric limit
+  TimeStamp ts = converter.GetTimeStampFromSystemTime(nearRangeMin, timeGetter);
+  EXPECT_TS(ts, 0);
+
+  // Advance to value near max numeric limit
+  MockTimeStamp::Advance(gap);
+  ts = converter.GetTimeStampFromSystemTime(nearRangeMax, unused);
+  EXPECT_TS(ts, gap);
+
+  // Advance by another full wraparound of the time. This loses some precision
+  // so we have to do the FUZZY match
+  MockTimeStamp::Advance(wrapPeriod);
+  ts = converter.GetTimeStampFromSystemTime(nearRangeMax, unused);
+  EXPECT_TS_FUZZY(ts, gap + wrapPeriod);
+}
+
+TEST(TimeConverter, HalfRangeBoundary)
+{
+  MockTimeStamp::Init();
+
+  GTestTime max = std::numeric_limits<GTestTime>::max();
+  GTestTime min = std::numeric_limits<GTestTime>::min();
+  double fullRange = (double)max - (double)min;
+  double wrapPeriod = fullRange + 1.0;
+  GTestTime halfRange = (GTestTime)(fullRange / 2.0);
+  GTestTime halfWrapPeriod = (GTestTime)(wrapPeriod / 2.0);
+
+  TimeConverter converter;
+
+  GTestTime firstEvent = 10;
+  MockCurrentTimeGetter timeGetter(firstEvent);
+  UnusedCurrentTimeGetter<GTestTime> unused;
+
+  // Set reference time
+  TimeStamp ts = converter.GetTimeStampFromSystemTime(firstEvent, timeGetter);
+  EXPECT_TS(ts, 0);
+
+  // Advance event time by just under the half-period, to trigger about as big
+  // a forwards skew as we possibly can.
+  GTestTime secondEvent = firstEvent + (halfWrapPeriod - 1);
+  ts = converter.GetTimeStampFromSystemTime(secondEvent, unused);
+  EXPECT_TS(ts, 0);
+
+  // The above forwards skew will have reset the reference timestamp. Now
+  // advance Now time by just under the half-range, to trigger about as big
+  // a backwards skew as we possibly can.
+  MockTimeStamp::Advance(halfRange - 1);
+  ts = converter.GetTimeStampFromSystemTime(secondEvent, unused);
+  EXPECT_TS(ts, 0);
+}
+
+TEST(TimeConverter, FractionalMillisBug1626734)
+{
+  MockTimeStamp::Init();
+
+  TimeConverter converter;
+
+  GTestTime eventTime = 10;
+  MockCurrentTimeGetter timeGetter(eventTime);
+  UnusedCurrentTimeGetter<GTestTime> unused;
+
+  TimeStamp ts = converter.GetTimeStampFromSystemTime(eventTime, timeGetter);
+  EXPECT_TS(ts, 0);
+
+  MockTimeStamp::Advance(0.2);
+  ts = converter.GetTimeStampFromSystemTime(eventTime, unused);
+  EXPECT_TS(ts, 0);
+
+  MockTimeStamp::Advance(0.9);
+  TimeStamp ts2 = converter.GetTimeStampFromSystemTime(eventTime, unused);
+  EXPECT_TS(ts2, 0);
+
+  // Since ts2 came from a "future" call relative to ts, we expect ts2 to not
+  // be "before" ts. (i.e. time shouldn't go backwards, even by fractional
+  // milliseconds). This assertion is technically already implied by the
+  // EXPECT_TS checks above, but fixing this assertion is the end result that
+  // we wanted in bug 1626734 so it feels appropriate to recheck it explicitly.
+  EXPECT_TRUE(ts <= ts2);
+}
diff --git a/widget/tests/gtest/TestTouchResampler.cpp b/widget/tests/gtest/TestTouchResampler.cpp
new file mode 100644
index 0000000000..1a5b8e2430
--- /dev/null
+++ b/widget/tests/gtest/TestTouchResampler.cpp
@@ -0,0 +1,941 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <initializer_list>
+#include "InputData.h"
+#include "Units.h"
+#include "gtest/gtest.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/TimeStamp.h"
+#include "TouchResampler.h"
+
+using namespace mozilla;
+using widget::TouchResampler;
+
+class TouchResamplerTest : public ::testing::Test {
+ protected:
+  virtual void SetUp() { baseTimeStamp = TimeStamp::Now(); }
+
+  TimeStamp Time(double aMilliseconds) {
+    return baseTimeStamp + TimeDuration::FromMilliseconds(aMilliseconds);
+  }
+
+  uint64_t ProcessEvent(
+      MultiTouchInput::MultiTouchType aType,
+      std::initializer_list<std::pair<TimeStamp, ScreenIntPoint>>
+          aHistoricalData,
+      const TimeStamp& aTimeStamp, const ScreenIntPoint& aPosition) {
+    MultiTouchInput input(aType, 0, aTimeStamp, 0);
+    input.mTouches.AppendElement(SingleTouchData(1, aPosition, {}, 0.0f, 0.0f));
+    for (const auto& histData : aHistoricalData) {
+      input.mTouches[0].mHistoricalData.AppendElement(
+          SingleTouchData::HistoricalTouchData{
+              histData.first, histData.second, {}, {}, 0.0f, 0.0f});
+    }
+    return resampler.ProcessEvent(std::move(input));
+  }
+
+  void CheckTime(const TimeStamp& aTimeStamp,
+                 const TimeStamp& aExpectedTimeStamp) {
+    EXPECT_EQ((aTimeStamp - baseTimeStamp).ToMilliseconds(),
+              (aExpectedTimeStamp - baseTimeStamp).ToMilliseconds());
+  }
+
+  void CheckEvent(const MultiTouchInput& aEvent,
+                  MultiTouchInput::MultiTouchType aExpectedType,
+                  std::initializer_list<std::pair<TimeStamp, ScreenIntPoint>>
+                      aExpectedHistoricalData,
+                  const TimeStamp& aExpectedTimeStamp,
+                  const ScreenIntPoint& aExpectedPosition) {
+    EXPECT_EQ(aEvent.mType, aExpectedType);
+    EXPECT_EQ(aEvent.mTouches.Length(), size_t(1));
+    EXPECT_EQ(aEvent.mTouches[0].mHistoricalData.Length(),
+              aExpectedHistoricalData.size());
+    for (size_t i = 0; i < aExpectedHistoricalData.size(); i++) {
+      CheckTime(aEvent.mTouches[0].mHistoricalData[i].mTimeStamp,
+                aExpectedHistoricalData.begin()[i].first);
+      EXPECT_EQ(aEvent.mTouches[0].mHistoricalData[i].mScreenPoint,
+                aExpectedHistoricalData.begin()[i].second);
+    }
+    CheckTime(aEvent.mTimeStamp, aExpectedTimeStamp);
+    EXPECT_EQ(aEvent.mTouches[0].mScreenPoint, aExpectedPosition);
+  }
+
+  struct ExpectedOutgoingEvent {
+    Maybe<uint64_t> mEventId;
+    MultiTouchInput::MultiTouchType mType = MultiTouchInput::MULTITOUCH_START;
+    std::initializer_list<std::pair<TimeStamp, ScreenIntPoint>> mHistoricalData;
+    TimeStamp mTimeStamp;
+    ScreenIntPoint mPosition;
+  };
+
+  void CheckOutgoingEvents(
+      std::initializer_list<ExpectedOutgoingEvent> aExpectedEvents) {
+    auto outgoing = resampler.ConsumeOutgoingEvents();
+    EXPECT_EQ(outgoing.size(), aExpectedEvents.size());
+    for (const auto& expectedEvent : aExpectedEvents) {
+      auto outgoingEvent = std::move(outgoing.front());
+      outgoing.pop();
+
+      EXPECT_EQ(outgoingEvent.mEventId, expectedEvent.mEventId);
+      CheckEvent(outgoingEvent.mEvent, expectedEvent.mType,
+                 expectedEvent.mHistoricalData, expectedEvent.mTimeStamp,
+                 expectedEvent.mPosition);
+    }
+  }
+
+  TimeStamp baseTimeStamp;
+  TouchResampler resampler;
+};
+
+TEST_F(TouchResamplerTest, BasicExtrapolation) {
+  // Execute the following sequence:
+  //
+  // 0----------10-------16-----20---------------32------------
+  // * touchstart at (10, 10)
+  //             * touchmove at (20, 20)
+  //                      * frame
+  //                             * touchend at (20, 20)
+  //                                              * frame
+  //
+  // And expect the following output:
+  //
+  // 0----------10-------16-----20---------------32------------
+  // * touchstart at (10, 10)
+  //                      * touchmove at (26, 26)
+  //                      * touchmove at (20, 20)
+  //                             * touchend at (20, 20)
+  //
+  // The first frame should emit an extrapolated touchmove from the position
+  // data in the touchstart and touchmove events.
+  // The touchend should force a synthesized touchmove that returns back to a
+  // non-resampled position.
+
+  EXPECT_FALSE(resampler.InTouchingState());
+
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(10, 10));
+  EXPECT_TRUE(resampler.InTouchingState());
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE, {}, Time(10.0),
+                              ScreenIntPoint(20, 20));
+
+  resampler.NotifyFrame(Time(16.0));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(10, 10)},
+
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(10.0), ScreenIntPoint(20, 20)}},
+       Time(16.0),
+       ScreenIntPoint(26, 26)},
+  });
+
+  auto idEnd2 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(20.0),
+                             ScreenIntPoint(20, 20));
+
+  EXPECT_FALSE(resampler.InTouchingState());
+
+  CheckOutgoingEvents({
+      {Nothing(),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {},
+       Time(16.0),
+       ScreenIntPoint(20, 20)},
+
+      {Some(idEnd2),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(20.0),
+       ScreenIntPoint(20, 20)},
+  });
+
+  // No more events should be produced from here on out.
+  resampler.NotifyFrame(Time(32.0));
+  auto outgoing = resampler.ConsumeOutgoingEvents();
+  EXPECT_TRUE(outgoing.empty());
+}
+
+TEST_F(TouchResamplerTest, BasicInterpolation) {
+  // Same test as BasicExtrapolation, but with a frame time that's 10ms earlier.
+  //
+  // Execute the following sequence:
+  //
+  // 0------6---10-----------20--22------------30-------------
+  // * touchstart at (10, 10)
+  //             * touchmove at (20, 20)
+  //        * frame
+  //                          * touchend at (20, 20)
+  //                              * frame
+  //
+  // And expect the following output:
+  //
+  // 0------6---10-----------20--22------------30-------------
+  // * touchstart at (10, 10)
+  //        * touchmove (16, 16)
+  //             * touchmove (20, 20)
+  //                          * touchend at (20, 20)
+  //
+  // The first frame should emit an interpolated touchmove from the position
+  // data in the touchstart and touchmove events.
+  // The touchend should create a touchmove that returns back to a non-resampled
+  // position.
+
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(10, 10));
+  EXPECT_TRUE(resampler.InTouchingState());
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE, {}, Time(10.0),
+                              ScreenIntPoint(20, 20));
+
+  resampler.NotifyFrame(Time(6.0));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(10, 10)},
+
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {},
+       Time(6.0),
+       ScreenIntPoint(16, 16)},
+  });
+
+  auto idEnd2 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(20.0),
+                             ScreenIntPoint(20, 20));
+  EXPECT_FALSE(resampler.InTouchingState());
+
+  CheckOutgoingEvents({
+      {Nothing(),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {},
+       Time(10.0),
+       ScreenIntPoint(20, 20)},
+
+      {Some(idEnd2),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(20.0),
+       ScreenIntPoint(20, 20)},
+  });
+
+  // No more events should be produced from here on out.
+  resampler.NotifyFrame(Time(22.0));
+  auto outgoing = resampler.ConsumeOutgoingEvents();
+  EXPECT_TRUE(outgoing.empty());
+}
+
+TEST_F(TouchResamplerTest, InterpolationFromHistoricalData) {
+  // Interpolate from the historical data in a touch move event.
+  //
+  // Execute the following sequence:
+  //
+  // 0----------10-------16-----20-----------30--32------------
+  // * touchstart at (10, 10)
+  //             * [hist] at (20, 25) for
+  //             `---------------* touchmove at (30, 30)
+  //                      * frame
+  //                                          * touchend at (30, 30)
+  //                                              * frame
+  //
+  // And expect the following output:
+  //
+  // 0----------10-------16-----20-----------30--32------------
+  // * touchstart at (10, 10)
+  //             * [hist] at (20, 25) for
+  //             `--------* touchmove at (26, 28)
+  //                             * touchmove at (30, 30)
+  //                                          * touchend at (30, 30)
+  //
+  // The first frame should emit an interpolated touchmove from the position
+  // data in the touchmove event, and integrate the historical data point into
+  // the resampled event.
+  // The touchend should force a synthesized touchmove that returns back to a
+  // non-resampled position.
+
+  // This also tests that interpolation works for both x and y, by giving the
+  // historical datapoint different values for x and y.
+  // (26, 28) is 60% of the way from (20, 25) to (30, 30).
+
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(10, 10));
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(10.0), ScreenIntPoint(20, 25)}},
+                              Time(20.0), ScreenIntPoint(30, 30));
+  resampler.NotifyFrame(Time(16.0));
+  auto idEnd2 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(30.0),
+                             ScreenIntPoint(30, 30));
+  resampler.NotifyFrame(Time(32.0));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(10, 10)},
+
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(10.0), ScreenIntPoint(20, 25)}},
+       Time(16.0),
+       ScreenIntPoint(26, 28)},
+
+      {Nothing(),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {},
+       Time(20.0),
+       ScreenIntPoint(30, 30)},
+
+      {Some(idEnd2),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(30.0),
+       ScreenIntPoint(30, 30)},
+  });
+}
+
+TEST_F(TouchResamplerTest, MultipleTouches) {
+  EXPECT_FALSE(resampler.InTouchingState());
+
+  // Touch start
+  MultiTouchInput inputStart0(MultiTouchInput::MULTITOUCH_START, 0, Time(0.0),
+                              0);
+  inputStart0.mTouches.AppendElement(
+      SingleTouchData(1, ScreenIntPoint(10, 10), {}, 0.0f, 0.0f));
+  auto idStart0 = resampler.ProcessEvent(std::move(inputStart0));
+  EXPECT_TRUE(resampler.InTouchingState());
+
+  // Touch move
+  MultiTouchInput inputMove1(MultiTouchInput::MULTITOUCH_MOVE, 0, Time(20.0),
+                             0);
+  inputMove1.mTouches.AppendElement(
+      SingleTouchData(1, ScreenIntPoint(30, 30), {}, 0.0f, 0.0f));
+  inputMove1.mTouches[0].mHistoricalData.AppendElement(
+      SingleTouchData::HistoricalTouchData{
+          Time(10.0), ScreenIntPoint(20, 25), {}, {}, 0.0f, 0.0f});
+  auto idMove1 = resampler.ProcessEvent(std::move(inputMove1));
+  EXPECT_TRUE(resampler.InTouchingState());
+
+  // Frame
+  resampler.NotifyFrame(Time(16.0));
+
+  // Touch move
+  MultiTouchInput inputMove2(MultiTouchInput::MULTITOUCH_MOVE, 0, Time(30.0),
+                             0);
+  inputMove2.mTouches.AppendElement(
+      SingleTouchData(1, ScreenIntPoint(30, 40), {}, 0.0f, 0.0f));
+  auto idMove2 = resampler.ProcessEvent(std::move(inputMove2));
+  EXPECT_TRUE(resampler.InTouchingState());
+
+  // Touch start
+  MultiTouchInput inputStart3(MultiTouchInput::MULTITOUCH_START, 0, Time(30.0),
+                              0);
+  inputStart3.mTouches.AppendElement(
+      SingleTouchData(2, ScreenIntPoint(100, 10), {}, 0.0f, 0.0f));
+  inputStart3.mTouches.AppendElement(
+      SingleTouchData(1, ScreenIntPoint(30, 40), {}, 0.0f, 0.0f));
+  auto idStart3 = resampler.ProcessEvent(std::move(inputStart3));
+  EXPECT_TRUE(resampler.InTouchingState());
+
+  // Touch move
+  MultiTouchInput inputMove4(MultiTouchInput::MULTITOUCH_MOVE, 0, Time(40.0),
+                             0);
+  inputMove4.mTouches.AppendElement(
+      SingleTouchData(1, ScreenIntPoint(30, 50), {}, 0.0f, 0.0f));
+  inputMove4.mTouches.AppendElement(
+      SingleTouchData(2, ScreenIntPoint(100, 30), {}, 0.0f, 0.0f));
+  auto idMove4 = resampler.ProcessEvent(std::move(inputMove4));
+  EXPECT_TRUE(resampler.InTouchingState());
+
+  // Frame
+  resampler.NotifyFrame(Time(32.0));
+
+  // Touch move
+  MultiTouchInput inputMove5(MultiTouchInput::MULTITOUCH_MOVE, 0, Time(50.0),
+                             0);
+  inputMove5.mTouches.AppendElement(
+      SingleTouchData(1, ScreenIntPoint(30, 60), {}, 0.0f, 0.0f));
+  inputMove5.mTouches.AppendElement(
+      SingleTouchData(2, ScreenIntPoint(100, 40), {}, 0.0f, 0.0f));
+  auto idMove5 = resampler.ProcessEvent(std::move(inputMove5));
+  EXPECT_TRUE(resampler.InTouchingState());
+
+  // Touch end
+  MultiTouchInput inputEnd6(MultiTouchInput::MULTITOUCH_END, 0, Time(50.0), 0);
+  // Touch point with identifier 1 is lifted
+  inputEnd6.mTouches.AppendElement(
+      SingleTouchData(1, ScreenIntPoint(30, 60), {}, 0.0f, 0.0f));
+  auto idEnd6 = resampler.ProcessEvent(std::move(inputEnd6));
+  EXPECT_TRUE(resampler.InTouchingState());
+
+  // Frame
+  resampler.NotifyFrame(Time(48.0));
+
+  // Touch move
+  MultiTouchInput inputMove7(MultiTouchInput::MULTITOUCH_MOVE, 0, Time(60.0),
+                             0);
+  inputMove7.mTouches.AppendElement(
+      SingleTouchData(2, ScreenIntPoint(100, 60), {}, 0.0f, 0.0f));
+  auto idMove7 = resampler.ProcessEvent(std::move(inputMove7));
+  EXPECT_TRUE(resampler.InTouchingState());
+
+  // Frame
+  resampler.NotifyFrame(Time(64.0));
+
+  // Touch end
+  MultiTouchInput inputEnd8(MultiTouchInput::MULTITOUCH_END, 0, Time(70.0), 0);
+  // Touch point with identifier 2 is lifted
+  inputEnd8.mTouches.AppendElement(
+      SingleTouchData(2, ScreenIntPoint(100, 60), {}, 0.0f, 0.0f));
+  auto idEnd8 = resampler.ProcessEvent(std::move(inputEnd8));
+  EXPECT_FALSE(resampler.InTouchingState());
+
+  // Check outgoing events
+  auto outgoing = resampler.ConsumeOutgoingEvents();
+  EXPECT_EQ(outgoing.size(), size_t(9));
+
+  auto outgoingStart0 = std::move(outgoing.front());
+  outgoing.pop();
+  EXPECT_EQ(outgoingStart0.mEventId, Some(idStart0));
+  CheckEvent(outgoingStart0.mEvent, MultiTouchInput::MULTITOUCH_START, {},
+             Time(0.0), ScreenIntPoint(10, 10));
+
+  auto outgoingMove1 = std::move(outgoing.front());
+  outgoing.pop();
+  EXPECT_EQ(outgoingMove1.mEventId, Some(idMove1));
+  // (26, 28) is 60% of the way from (20, 25) to (30, 30).
+  CheckEvent(outgoingMove1.mEvent, MultiTouchInput::MULTITOUCH_MOVE,
+             {{Time(10.0), ScreenIntPoint(20, 25)}}, Time(16.0),
+             ScreenIntPoint(26, 28));
+
+  auto outgoingMove2 = std::move(outgoing.front());
+  outgoing.pop();
+  EXPECT_EQ(outgoingMove2.mEventId, Some(idMove2));
+  CheckEvent(outgoingMove2.mEvent, MultiTouchInput::MULTITOUCH_MOVE,
+             {{Time(20.0), ScreenIntPoint(30, 30)}}, Time(30.0),
+             ScreenIntPoint(30, 40));
+
+  auto outgoingStart3 = std::move(outgoing.front());
+  outgoing.pop();
+  EXPECT_EQ(outgoingStart3.mEventId, Some(idStart3));
+  EXPECT_EQ(outgoingStart3.mEvent.mType, MultiTouchInput::MULTITOUCH_START);
+  CheckTime(outgoingStart3.mEvent.mTimeStamp, Time(30.0));
+  EXPECT_EQ(outgoingStart3.mEvent.mTouches.Length(), size_t(2));
+  // touch order should be taken from the original touch start event
+  EXPECT_EQ(outgoingStart3.mEvent.mTouches[0].mIdentifier, 2);
+  EXPECT_EQ(outgoingStart3.mEvent.mTouches[0].mScreenPoint,
+            ScreenIntPoint(100, 10));
+  EXPECT_EQ(outgoingStart3.mEvent.mTouches[1].mIdentifier, 1);
+  EXPECT_EQ(outgoingStart3.mEvent.mTouches[1].mScreenPoint,
+            ScreenIntPoint(30, 40));
+
+  auto outgoingMove4 = std::move(outgoing.front());
+  outgoing.pop();
+  EXPECT_EQ(outgoingMove4.mEventId, Some(idMove4));
+  EXPECT_EQ(outgoingMove4.mEvent.mType, MultiTouchInput::MULTITOUCH_MOVE);
+  CheckTime(outgoingMove4.mEvent.mTimeStamp, Time(32.0));
+  EXPECT_EQ(outgoingMove4.mEvent.mTouches.Length(), size_t(2));
+  // Touch order should be taken from the original touch move event.
+  // Both touches should be resampled.
+  EXPECT_EQ(outgoingMove4.mEvent.mTouches[0].mIdentifier, 1);
+  EXPECT_EQ(outgoingMove4.mEvent.mTouches[0].mScreenPoint,
+            ScreenIntPoint(30, 42));
+  EXPECT_EQ(outgoingMove4.mEvent.mTouches[1].mIdentifier, 2);
+  EXPECT_EQ(outgoingMove4.mEvent.mTouches[1].mScreenPoint,
+            ScreenIntPoint(100, 14));
+
+  auto outgoingMove5 = std::move(outgoing.front());
+  outgoing.pop();
+  EXPECT_EQ(outgoingMove5.mEventId, Some(idMove5));
+  EXPECT_EQ(outgoingMove5.mEvent.mType, MultiTouchInput::MULTITOUCH_MOVE);
+  CheckTime(outgoingMove5.mEvent.mTimeStamp, Time(50.0));
+  EXPECT_EQ(outgoingMove5.mEvent.mTouches.Length(), size_t(2));
+  // touch order should be taken from the original touch move event
+  EXPECT_EQ(outgoingMove5.mEvent.mTouches[0].mIdentifier, 1);
+  EXPECT_EQ(outgoingMove5.mEvent.mTouches[0].mScreenPoint,
+            ScreenIntPoint(30, 60));
+  EXPECT_EQ(outgoingMove5.mEvent.mTouches[0].mHistoricalData.Length(),
+            size_t(1));
+  CheckTime(outgoingMove5.mEvent.mTouches[0].mHistoricalData[0].mTimeStamp,
+            Time(40.0));
+  EXPECT_EQ(outgoingMove5.mEvent.mTouches[0].mHistoricalData[0].mScreenPoint,
+            ScreenIntPoint(30, 50));
+  EXPECT_EQ(outgoingMove5.mEvent.mTouches[1].mIdentifier, 2);
+  EXPECT_EQ(outgoingMove5.mEvent.mTouches[1].mScreenPoint,
+            ScreenIntPoint(100, 40));
+  EXPECT_EQ(outgoingMove5.mEvent.mTouches[1].mHistoricalData.Length(),
+            size_t(1));
+  CheckTime(outgoingMove5.mEvent.mTouches[1].mHistoricalData[0].mTimeStamp,
+            Time(40.0));
+  EXPECT_EQ(outgoingMove5.mEvent.mTouches[1].mHistoricalData[0].mScreenPoint,
+            ScreenIntPoint(100, 30));
+
+  auto outgoingEnd6 = std::move(outgoing.front());
+  outgoing.pop();
+  EXPECT_EQ(outgoingEnd6.mEventId, Some(idEnd6));
+  CheckEvent(outgoingEnd6.mEvent, MultiTouchInput::MULTITOUCH_END, {},
+             Time(50.0), ScreenIntPoint(30, 60));
+
+  auto outgoingMove7 = std::move(outgoing.front());
+  outgoing.pop();
+  EXPECT_EQ(outgoingMove7.mEventId, Some(idMove7));
+  // No extrapolation because the frame at 64.0 cleared the data points because
+  // there was no pending touch move event at that point
+  CheckEvent(outgoingMove7.mEvent, MultiTouchInput::MULTITOUCH_MOVE, {},
+             Time(60.0), ScreenIntPoint(100, 60));
+  EXPECT_EQ(outgoingMove7.mEvent.mTouches[0].mIdentifier, 2);
+
+  auto outgoingEnd8 = std::move(outgoing.front());
+  outgoing.pop();
+  EXPECT_EQ(outgoingEnd8.mEventId, Some(idEnd8));
+  CheckEvent(outgoingEnd8.mEvent, MultiTouchInput::MULTITOUCH_END, {},
+             Time(70.0), ScreenIntPoint(100, 60));
+}
+
+TEST_F(TouchResamplerTest, MovingPauses) {
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(10, 10));
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE, {}, Time(10.0),
+                              ScreenIntPoint(20, 20));
+  resampler.NotifyFrame(Time(16.0));
+  auto idMove2 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE, {}, Time(30.0),
+                              ScreenIntPoint(40, 40));
+  resampler.NotifyFrame(Time(32.0));
+  auto idMove3 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE, {}, Time(40.0),
+                              ScreenIntPoint(50, 40));
+  resampler.NotifyFrame(Time(48.0));
+  resampler.NotifyFrame(Time(64.0));
+  auto idEnd4 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(70.0),
+                             ScreenIntPoint(50, 40));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(10, 10)},
+
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(10.0), ScreenIntPoint(20, 20)}},
+       Time(16.0),
+       ScreenIntPoint(26, 26)},
+
+      {Some(idMove2),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(30.0), ScreenIntPoint(40, 40)}},
+       Time(32.0),
+       ScreenIntPoint(42, 42)},
+
+      {Some(idMove3),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(40.0), ScreenIntPoint(50, 40)}},
+       Time(48.0),
+       ScreenIntPoint(58, 40)},
+
+      // There was no event between two frames here, so we expect a reset event,
+      // so that we pause at a non-resampled position.
+      {Nothing(),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {},
+       Time(48.0),
+       ScreenIntPoint(50, 40)},
+
+      {Some(idEnd4),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(70.0),
+       ScreenIntPoint(50, 40)},
+  });
+}
+
+TEST_F(TouchResamplerTest, MixedInterAndExtrapolation) {
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(0, 0));
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE, {}, Time(10.0),
+                              ScreenIntPoint(0, 10));
+  resampler.NotifyFrame(Time(11.0));  // 16 - 5
+  auto idMove2 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(20.0), ScreenIntPoint(0, 20)}}, Time(30.0),
+                              ScreenIntPoint(0, 30));
+  resampler.NotifyFrame(Time(27.0));  // 32 - 5
+  auto idMove3 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE, {}, Time(40.0),
+                              ScreenIntPoint(0, 40));
+  resampler.NotifyFrame(Time(43.0));  // 48 - 5
+  auto idMove4 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(50.0), ScreenIntPoint(0, 50)}}, Time(60.0),
+                              ScreenIntPoint(0, 60));
+  resampler.NotifyFrame(Time(59.0));  // 64 - 5
+  auto idEnd5 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(70.0),
+                             ScreenIntPoint(0, 60));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(0, 0)},
+
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(10.0), ScreenIntPoint(0, 10)}},
+       Time(11.0),
+       ScreenIntPoint(0, 11)},
+
+      {Some(idMove2),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(20.0), ScreenIntPoint(0, 20)}},
+       Time(27.0),
+       ScreenIntPoint(0, 27)},
+
+      {Some(idMove3),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(30.0), ScreenIntPoint(0, 30)},
+        {Time(40.0), ScreenIntPoint(0, 40)}},
+       Time(43.0),
+       ScreenIntPoint(0, 43)},
+
+      {Some(idMove4),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(50.0), ScreenIntPoint(0, 50)}},
+       Time(59.0),
+       ScreenIntPoint(0, 59)},
+
+      {Nothing(),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {},
+       Time(60.0),
+       ScreenIntPoint(0, 60)},
+
+      {Some(idEnd5),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(70.0),
+       ScreenIntPoint(0, 60)},
+  });
+}
+
+TEST_F(TouchResamplerTest, MultipleMoveEvents) {
+  // Test what happens if multiple touch move events appear between two frames.
+  // This scenario shouldn't occur on Android but we should be able to deal with
+  // it anyway. Check that we don't discard any event IDs.
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(0, 0));
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE, {}, Time(10.0),
+                              ScreenIntPoint(0, 10));
+  resampler.NotifyFrame(Time(11.0));  // 16 - 5
+  auto idMove2 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(20.0), ScreenIntPoint(0, 20)}}, Time(30.0),
+                              ScreenIntPoint(0, 30));
+  auto idMove3 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE, {}, Time(40.0),
+                              ScreenIntPoint(0, 40));
+  auto idMove4 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(45.0), ScreenIntPoint(0, 45)}}, Time(50.0),
+                              ScreenIntPoint(0, 50));
+  auto idMove5 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE, {}, Time(55.0),
+                              ScreenIntPoint(0, 55));
+  resampler.NotifyFrame(Time(43.0));  // 48 - 5
+  resampler.NotifyFrame(Time(59.0));  // 64 - 5
+  auto idEnd5 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(70.0),
+                             ScreenIntPoint(0, 60));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(0, 0)},
+
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(10.0), ScreenIntPoint(0, 10)}},
+       Time(11.0),
+       ScreenIntPoint(0, 11)},
+
+      {Some(idMove2),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(20.0), ScreenIntPoint(0, 20)}},
+       Time(30.0),
+       ScreenIntPoint(0, 30)},
+
+      {Some(idMove3),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {},
+       Time(40.0),
+       ScreenIntPoint(0, 40)},
+
+      {Some(idMove4),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {},
+       Time(43.0),
+       ScreenIntPoint(0, 43)},
+
+      {Some(idMove5),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(45.0), ScreenIntPoint(0, 45)},
+        {Time(50.0), ScreenIntPoint(0, 50)},
+        {Time(55.0), ScreenIntPoint(0, 55)}},
+       Time(59.0),
+       ScreenIntPoint(0, 59)},
+
+      {Nothing(),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {},
+       Time(59.0),
+       ScreenIntPoint(0, 55)},
+
+      {Some(idEnd5),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(70.0),
+       ScreenIntPoint(0, 60)},
+  });
+}
+
+TEST_F(TouchResamplerTest, LimitFuturePrediction) {
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(0, 0));
+  // Fingers move until time 44, then pause. UI thread is occupied until 64.
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(20.0), ScreenIntPoint(0, 20)},
+                               {Time(32.0), ScreenIntPoint(0, 32)}},
+                              Time(44.0), ScreenIntPoint(0, 44));
+  resampler.NotifyFrame(Time(59.0));  // 64 - 5
+  auto idEnd2 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(70.0),
+                             ScreenIntPoint(0, 44));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(0, 0)},
+
+      // kTouchResampleMaxPredictMs == 8
+      // Refuse to predict more than 8ms into the future, the fingers might have
+      // paused. Make an event for time 52 (= 44 + 8) instead of 59.
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(20.0), ScreenIntPoint(0, 20)},
+        {Time(32.0), ScreenIntPoint(0, 32)},
+        {Time(44.0), ScreenIntPoint(0, 44)}},
+       Time(52.0),
+       ScreenIntPoint(0, 52)},
+
+      {Nothing(),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {},
+       Time(52.0),
+       ScreenIntPoint(0, 44)},
+
+      {Some(idEnd2),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(70.0),
+       ScreenIntPoint(0, 44)},
+  });
+}
+
+TEST_F(TouchResamplerTest, LimitBacksampling) {
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(0, 0));
+  // Fingers move until time 44, then pause. UI thread is occupied until 64.
+  // Then we get a frame callback with a very outdated frametime.
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(20.0), ScreenIntPoint(0, 20)},
+                               {Time(32.0), ScreenIntPoint(0, 32)}},
+                              Time(44.0), ScreenIntPoint(0, 44));
+  resampler.NotifyFrame(Time(11.0));  // 16 - 5
+  auto idEnd2 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(70.0),
+                             ScreenIntPoint(0, 44));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(0, 0)},
+
+      // kTouchResampleMaxBacksampleMs == 20
+      // Refuse to sample further back than 20ms before the last data point.
+      // Make an event for time 24 (= 44 - 20) instead of time 11.
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(20.0), ScreenIntPoint(0, 20)}},
+       Time(24.0),
+       ScreenIntPoint(0, 24)},
+
+      {Nothing(),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(32.0), ScreenIntPoint(0, 32)}},
+       Time(44.0),
+       ScreenIntPoint(0, 44)},
+
+      {Some(idEnd2),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(70.0),
+       ScreenIntPoint(0, 44)},
+  });
+}
+
+TEST_F(TouchResamplerTest, DontExtrapolateFromOldTouch) {
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(0, 0));
+  // Fingers move until time 40, then pause. UI thread is occupied until 64.
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(20.0), ScreenIntPoint(0, 20)},
+                               {Time(30.0), ScreenIntPoint(0, 30)}},
+                              Time(40.0), ScreenIntPoint(0, 40));
+  resampler.NotifyFrame(Time(59.0));  // 64 - 5
+  auto idEnd2 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(70.0),
+                             ScreenIntPoint(0, 44));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(0, 0)},
+
+      // kTouchResampleOldTouchThresholdMs == 17
+      // Refuse to extrapolate from a data point that's more than 17ms older
+      // than the frame time.
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(20.0), ScreenIntPoint(0, 20)},
+        {Time(30.0), ScreenIntPoint(0, 30)}},
+       Time(40.0),
+       ScreenIntPoint(0, 40)},
+
+      {Some(idEnd2),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(70.0),
+       ScreenIntPoint(0, 44)},
+  });
+}
+
+TEST_F(TouchResamplerTest, DontExtrapolateIfTooOld) {
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(0, 0));
+  // Fingers move until time 10, pause, and move again at 55.
+  // UI thread is occupied until 64.
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(10.0), ScreenIntPoint(0, 10)}}, Time(55.0),
+                              ScreenIntPoint(0, 55));
+  resampler.NotifyFrame(Time(59.0));  // 64 - 5
+  auto idEnd2 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(70.0),
+                             ScreenIntPoint(0, 60));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(0, 0)},
+
+      // kTouchResampleWindowSize == 40
+      // Refuse to resample between two data points that are more than 40ms
+      // apart.
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(10.0), ScreenIntPoint(0, 10)}},
+       Time(55.0),
+       ScreenIntPoint(0, 55)},
+
+      {Some(idEnd2),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(70.0),
+       ScreenIntPoint(0, 60)},
+  });
+}
+
+TEST_F(TouchResamplerTest, DontInterpolateIfTooOld) {
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(0, 0));
+  // Fingers move until time 10, pause, and move again at 60.
+  // UI thread is occupied until 64.
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(10.0), ScreenIntPoint(0, 10)}}, Time(60.0),
+                              ScreenIntPoint(0, 60));
+  resampler.NotifyFrame(Time(59.0));  // 64 - 5
+  auto idEnd2 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(70.0),
+                             ScreenIntPoint(0, 60));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(0, 0)},
+
+      // kTouchResampleWindowSize == 40
+      // Refuse to resample between two data points that are more than 40ms
+      // apart.
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(10.0), ScreenIntPoint(0, 10)}},
+       Time(60.0),
+       ScreenIntPoint(0, 60)},
+
+      {Some(idEnd2),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(70.0),
+       ScreenIntPoint(0, 60)},
+  });
+}
+
+TEST_F(TouchResamplerTest, DiscardOutdatedHistoricalData) {
+  auto idStart0 = ProcessEvent(MultiTouchInput::MULTITOUCH_START, {}, Time(0.0),
+                               ScreenIntPoint(0, 0));
+  auto idMove1 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(10.0), ScreenIntPoint(0, 10)}}, Time(16.0),
+                              ScreenIntPoint(0, 16));
+  resampler.NotifyFrame(Time(20.0));
+  auto idMove2 = ProcessEvent(MultiTouchInput::MULTITOUCH_MOVE,
+                              {{Time(18.0), ScreenIntPoint(0, 18)}}, Time(25.0),
+                              ScreenIntPoint(0, 25));
+  auto idEnd3 = ProcessEvent(MultiTouchInput::MULTITOUCH_END, {}, Time(35.0),
+                             ScreenIntPoint(0, 25));
+
+  CheckOutgoingEvents({
+      {Some(idStart0),
+       MultiTouchInput::MULTITOUCH_START,
+       {},
+       Time(0.0),
+       ScreenIntPoint(0, 0)},
+
+      {Some(idMove1),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {{Time(10.0), ScreenIntPoint(0, 10)},
+        {Time(16.0), ScreenIntPoint(0, 16)}},
+       Time(20.0),
+       ScreenIntPoint(0, 20)},
+
+      // Discard the historical data point from time 18, because we've already
+      // sent out an event with time 20 and don't want to go back before that.
+      {Some(idMove2),
+       MultiTouchInput::MULTITOUCH_MOVE,
+       {},
+       Time(25.0),
+       ScreenIntPoint(0, 25)},
+
+      {Some(idEnd3),
+       MultiTouchInput::MULTITOUCH_END,
+       {},
+       Time(35.0),
+       ScreenIntPoint(0, 25)},
+  });
+}
diff --git a/widget/tests/gtest/TestWinHeaderOnlyUtils.cpp b/widget/tests/gtest/TestWinHeaderOnlyUtils.cpp
new file mode 100644
index 0000000000..5ac361fea0
--- /dev/null
+++ b/widget/tests/gtest/TestWinHeaderOnlyUtils.cpp
@@ -0,0 +1,37 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "mozilla/WinHeaderOnlyUtils.h"
+
+#include <shlwapi.h>
+
+TEST(WinHeaderOnlyUtils, MozPathGetDriveNumber)
+{
+  constexpr auto TestPathGetDriveNumber = [](const wchar_t* aPath) {
+    return mozilla::MozPathGetDriveNumber(aPath) ==
+           ::PathGetDriveNumberW(aPath);
+  };
+  EXPECT_TRUE(TestPathGetDriveNumber(nullptr));
+  EXPECT_TRUE(TestPathGetDriveNumber(L""));
+  EXPECT_TRUE(TestPathGetDriveNumber(L" :"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"a:"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"C:\\file"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"x:/file"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"@:\\\\"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"B"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"abc:\\file"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"\\"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"\\:A"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"\\\\"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"\\\\\\"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"\\\\?"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"\\\\?\\"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"\\\\?\\\\"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"\\\\?\\c:\\"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"\\\\?\\A"));
+  EXPECT_TRUE(TestPathGetDriveNumber(L"\\\\?\\ \\"));
+}
diff --git a/widget/tests/gtest/TestWinMessageLoggingUtils.cpp b/widget/tests/gtest/TestWinMessageLoggingUtils.cpp
new file mode 100644
index 0000000000..b0ab09f866
--- /dev/null
+++ b/widget/tests/gtest/TestWinMessageLoggingUtils.cpp
@@ -0,0 +1,101 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

+/* vim: set ts=8 sts=2 et sw=2 tw=80: */

+/* This Source Code Form is subject to the terms of the Mozilla Public

+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,

+ * You can obtain one at http://mozilla.org/MPL/2.0/. */

+

+#include "gtest/gtest.h"

+#include "windows/nsWindowDbg.h"

+

+using namespace mozilla;

+using namespace mozilla::widget;

+

+TEST(WinMessageLoggingUtils, AppendFlagsInfo_CombinationFlagsHandledFirst)

+{

+  const nsTArray<EnumValueAndName> flags = {

+      {0x3, "COMBO"}, {0x1, "ONE"}, {0x2, "TWO"}};

+  nsAutoCString result;

+  EXPECT_EQ(true, AppendFlagsInfo(result, 0x3, flags, nullptr));

+  EXPECT_STREQ("COMBO", result.get());

+}

+

+TEST(WinMessageLoggingUtils, AppendFlagsInfo_SingleFlag)

+{

+  const nsTArray<EnumValueAndName> flags = {

+      {0x1, "ONE"}, {0x2, "TWO"}, {0x4, "FOUR"}};

+  nsAutoCString result;

+  EXPECT_EQ(true, AppendFlagsInfo(result, 0x4, flags, nullptr));

+  EXPECT_STREQ("FOUR", result.get());

+}

+

+TEST(WinMessageLoggingUtils, AppendFlagsInfo_SingleFlagWithName)

+{

+  const nsTArray<EnumValueAndName> flags = {

+      {0x1, "ONE"}, {0x2, "TWO"}, {0x4, "FOUR"}};

+  nsAutoCString result;

+  EXPECT_EQ(true, AppendFlagsInfo(result, 0x4, flags, "paramName"));

+  EXPECT_STREQ("paramName=FOUR", result.get());

+}

+

+TEST(WinMessageLoggingUtils, AppendFlagsInfo_MultipleFlags)

+{

+  const nsTArray<EnumValueAndName> flags = {

+      {0x1, "ONE"}, {0x2, "TWO"}, {0x4, "FOUR"}};

+  nsAutoCString result;

+  EXPECT_EQ(true, AppendFlagsInfo(result, 0x5, flags, nullptr));

+  EXPECT_STREQ("ONE|FOUR", result.get());

+}

+

+TEST(WinMessageLoggingUtils, AppendFlagsInfo_NoFlags)

+{

+  const nsTArray<EnumValueAndName> flags = {

+      {0x1, "ONE"}, {0x2, "TWO"}, {0x4, "FOUR"}};

+  nsAutoCString result;

+  EXPECT_EQ(true, AppendFlagsInfo(result, 0x8, flags, nullptr));

+  EXPECT_STREQ("Unknown (0x00000008)", result.get());

+}

+

+TEST(WinMessageLoggingUtils, AppendFlagsInfo_OnlySomeFlagsMatch)

+{

+  const nsTArray<EnumValueAndName> flags = {

+      {0x1, "ONE"}, {0x2, "TWO"}, {0x4, "FOUR"}};

+  nsAutoCString result;

+  EXPECT_EQ(true, AppendFlagsInfo(result, 0x9, flags, nullptr));

+  EXPECT_STREQ("ONE|Unknown (0x00000008)", result.get());

+}

+

+TEST(WinMessageLoggingUtils, AppendFlagsInfo_FlagsMatch_NoZeroReturned)

+{

+  const nsTArray<EnumValueAndName> flags = {

+      {0x1, "ONE"}, {0x2, "TWO"}, {0x4, "FOUR"}, {0x0, "ZERO"}};

+  nsAutoCString result;

+  EXPECT_EQ(true, AppendFlagsInfo(result, 0x2, flags, nullptr));

+  EXPECT_STREQ("TWO", result.get());

+}

+

+TEST(WinMessageLoggingUtils, AppendFlagsInfo_NoFlagsMatch_NoZeroReturned)

+{

+  const nsTArray<EnumValueAndName> flags = {

+      {0x1, "ONE"}, {0x2, "TWO"}, {0x4, "FOUR"}, {0x0, "ZERO"}};

+  nsAutoCString result;

+  EXPECT_EQ(true, AppendFlagsInfo(result, 0x8, flags, nullptr));

+  EXPECT_STREQ("Unknown (0x00000008)", result.get());

+}

+

+TEST(WinMessageLoggingUtils, AppendFlagsInfo_NameAndNoFlagsMatch_NoZeroReturned)

+{

+  const nsTArray<EnumValueAndName> flags = {

+      {0x1, "ONE"}, {0x2, "TWO"}, {0x4, "FOUR"}, {0x0, "ZERO"}};

+  nsAutoCString result;

+  EXPECT_EQ(true, AppendFlagsInfo(result, 0x8, flags, "paramName"));

+  EXPECT_STREQ("paramName=Unknown (0x00000008)", result.get());

+}

+

+TEST(WinMessageLoggingUtils, AppendFlagsInfo_ValueIsZero_ZeroReturned)

+{

+  const nsTArray<EnumValueAndName> flags = {

+      {0x1, "ONE"}, {0x2, "TWO"}, {0x4, "FOUR"}, {0x0, "ZERO"}};

+  nsAutoCString result;

+  EXPECT_EQ(true, AppendFlagsInfo(result, 0x0, flags, nullptr));

+  EXPECT_STREQ("ZERO", result.get());

+}

diff --git a/widget/tests/gtest/TestWinWindowOcclusionTracker.cpp b/widget/tests/gtest/TestWinWindowOcclusionTracker.cpp
new file mode 100644
index 0000000000..5ef7e3f81c
--- /dev/null
+++ b/widget/tests/gtest/TestWinWindowOcclusionTracker.cpp
@@ -0,0 +1,162 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+
+#include <dwmapi.h>
+#include <windows.h>
+
+#include "MockWinWidget.h"
+#include "mozilla/widget/WinWindowOcclusionTracker.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+class WinWindowOcclusionTrackerTest : public ::testing::Test {
+ protected:
+  HWND CreateNativeWindow(DWORD aStyle, DWORD aExStyle) {
+    mMockWinWidget =
+        MockWinWidget::Create(WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN | aStyle,
+                              aExStyle, LayoutDeviceIntRect(0, 0, 100, 100));
+    EXPECT_NE(nullptr, mMockWinWidget.get());
+    HWND hwnd = mMockWinWidget->GetWnd();
+    HRGN region = ::CreateRectRgn(0, 0, 0, 0);
+    EXPECT_NE(nullptr, region);
+    if (::GetWindowRgn(hwnd, region) == COMPLEXREGION) {
+      // On Windows 7, the newly created window has a complex region, which
+      // means it will be ignored during the occlusion calculation. So, force
+      // it to have a simple region so that we get test coverage on win 7.
+      RECT boundingRect;
+      EXPECT_TRUE(::GetWindowRect(hwnd, &boundingRect));
+      HRGN rectangularRegion = ::CreateRectRgnIndirect(&boundingRect);
+      EXPECT_NE(nullptr, rectangularRegion);
+      ::SetWindowRgn(hwnd, rectangularRegion, /* bRedraw = */ TRUE);
+      ::DeleteObject(rectangularRegion);
+    }
+    ::DeleteObject(region);
+
+    ::ShowWindow(hwnd, SW_SHOWNORMAL);
+    EXPECT_TRUE(UpdateWindow(hwnd));
+    return hwnd;
+  }
+
+  // Wrapper around IsWindowVisibleAndFullyOpaque so only the test class
+  // needs to be a friend of NativeWindowOcclusionTrackerWin.
+  bool CheckWindowVisibleAndFullyOpaque(HWND aHWnd,
+                                        LayoutDeviceIntRect* aWinRect) {
+    bool ret = WinWindowOcclusionTracker::IsWindowVisibleAndFullyOpaque(
+        aHWnd, aWinRect);
+    // In general, if IsWindowVisibleAndFullyOpaque returns false, the
+    // returned rect should not be altered.
+    if (!ret) {
+      EXPECT_EQ(*aWinRect, LayoutDeviceIntRect(0, 0, 0, 0));
+    }
+    return ret;
+  }
+
+  RefPtr<MockWinWidget> mMockWinWidget;
+};
+
+TEST_F(WinWindowOcclusionTrackerTest, VisibleOpaqueWindow) {
+  HWND hwnd = CreateNativeWindow(/* aStyle = */ 0, /* aExStyle = */ 0);
+  LayoutDeviceIntRect returnedRect;
+  // Normal windows should be visible.
+  EXPECT_TRUE(CheckWindowVisibleAndFullyOpaque(hwnd, &returnedRect));
+
+  // Check that the returned rect == the actual window rect of the hwnd.
+  RECT winRect;
+  ASSERT_TRUE(::GetWindowRect(hwnd, &winRect));
+  EXPECT_EQ(returnedRect, LayoutDeviceIntRect(winRect.left, winRect.top,
+                                              winRect.right - winRect.left,
+                                              winRect.bottom - winRect.top));
+}
+
+TEST_F(WinWindowOcclusionTrackerTest, MinimizedWindow) {
+  HWND hwnd = CreateNativeWindow(/* aStyle = */ 0, /* aExStyle = */ 0);
+  LayoutDeviceIntRect winRect;
+  ::ShowWindow(hwnd, SW_MINIMIZE);
+  // Minimized windows are not considered visible.
+  EXPECT_FALSE(CheckWindowVisibleAndFullyOpaque(hwnd, &winRect));
+}
+
+TEST_F(WinWindowOcclusionTrackerTest, TransparentWindow) {
+  HWND hwnd = CreateNativeWindow(/* aStyle = */ 0, WS_EX_TRANSPARENT);
+  LayoutDeviceIntRect winRect;
+  // Transparent windows are not considered visible and opaque.
+  EXPECT_FALSE(CheckWindowVisibleAndFullyOpaque(hwnd, &winRect));
+}
+
+TEST_F(WinWindowOcclusionTrackerTest, ToolWindow) {
+  HWND hwnd = CreateNativeWindow(/* aStyle = */ 0, WS_EX_TOOLWINDOW);
+  LayoutDeviceIntRect winRect;
+  // Tool windows are not considered visible and opaque.
+  EXPECT_FALSE(CheckWindowVisibleAndFullyOpaque(hwnd, &winRect));
+}
+
+TEST_F(WinWindowOcclusionTrackerTest, LayeredAlphaWindow) {
+  HWND hwnd = CreateNativeWindow(/* aStyle = */ 0, WS_EX_LAYERED);
+  LayoutDeviceIntRect winRect;
+  BYTE alpha = 1;
+  DWORD flags = LWA_ALPHA;
+  COLORREF colorRef = RGB(1, 1, 1);
+  SetLayeredWindowAttributes(hwnd, colorRef, alpha, flags);
+  // Layered windows with alpha < 255 are not considered visible and opaque.
+  EXPECT_FALSE(CheckWindowVisibleAndFullyOpaque(hwnd, &winRect));
+}
+
+TEST_F(WinWindowOcclusionTrackerTest, UpdatedLayeredAlphaWindow) {
+  HWND hwnd = CreateNativeWindow(/* aStyle = */ 0, WS_EX_LAYERED);
+  LayoutDeviceIntRect winRect;
+  HDC hdc = ::CreateCompatibleDC(nullptr);
+  EXPECT_NE(nullptr, hdc);
+  BLENDFUNCTION blend = {AC_SRC_OVER, 0x00, 0xFF, AC_SRC_ALPHA};
+
+  ::UpdateLayeredWindow(hwnd, hdc, nullptr, nullptr, nullptr, nullptr,
+                        RGB(0xFF, 0xFF, 0xFF), &blend, ULW_OPAQUE);
+  // Layered windows set up with UpdateLayeredWindow instead of
+  // SetLayeredWindowAttributes should not be considered visible and opaque.
+  EXPECT_FALSE(CheckWindowVisibleAndFullyOpaque(hwnd, &winRect));
+  ::DeleteDC(hdc);
+}
+
+TEST_F(WinWindowOcclusionTrackerTest, LayeredNonAlphaWindow) {
+  HWND hwnd = CreateNativeWindow(/* aStyle = */ 0, WS_EX_LAYERED);
+  LayoutDeviceIntRect winRect;
+  BYTE alpha = 1;
+  DWORD flags = 0;
+  COLORREF colorRef = RGB(1, 1, 1);
+  ::SetLayeredWindowAttributes(hwnd, colorRef, alpha, flags);
+  // Layered non alpha windows are considered visible and opaque.
+  EXPECT_TRUE(CheckWindowVisibleAndFullyOpaque(hwnd, &winRect));
+}
+
+TEST_F(WinWindowOcclusionTrackerTest, ComplexRegionWindow) {
+  HWND hwnd = CreateNativeWindow(/* aStyle = */ 0, /* aExStyle = */ 0);
+  LayoutDeviceIntRect winRect;
+  // Create a region with rounded corners, which should be a complex region.
+  HRGN region = CreateRoundRectRgn(1, 1, 100, 100, 5, 5);
+  EXPECT_NE(nullptr, region);
+  ::SetWindowRgn(hwnd, region, /* bRedraw = */ TRUE);
+  // Windows with complex regions are not considered visible and fully opaque.
+  EXPECT_FALSE(CheckWindowVisibleAndFullyOpaque(hwnd, &winRect));
+  DeleteObject(region);
+}
+
+TEST_F(WinWindowOcclusionTrackerTest, PopupWindow) {
+  HWND hwnd = CreateNativeWindow(WS_POPUP, /* aExStyle = */ 0);
+  LayoutDeviceIntRect winRect;
+  // Normal Popup Windows are not considered visible.
+  EXPECT_FALSE(CheckWindowVisibleAndFullyOpaque(hwnd, &winRect));
+}
+
+TEST_F(WinWindowOcclusionTrackerTest, CloakedWindow) {
+  HWND hwnd = CreateNativeWindow(/* aStyle = */ 0, /* aExStyle = */ 0);
+  LayoutDeviceIntRect winRect;
+  BOOL cloak = TRUE;
+  ::DwmSetWindowAttribute(hwnd, DWMWA_CLOAK, &cloak, sizeof(cloak));
+  // Cloaked Windows are not considered visible.
+  EXPECT_FALSE(CheckWindowVisibleAndFullyOpaque(hwnd, &winRect));
+}
diff --git a/widget/tests/gtest/TestWinWindowOcclusionTrackerInteractive.cpp b/widget/tests/gtest/TestWinWindowOcclusionTrackerInteractive.cpp
new file mode 100644
index 0000000000..13cd95651c
--- /dev/null
+++ b/widget/tests/gtest/TestWinWindowOcclusionTrackerInteractive.cpp
@@ -0,0 +1,402 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+
+#include "MockWinWidget.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/widget/WinEventObserver.h"
+#include "mozilla/widget/WinWindowOcclusionTracker.h"
+#include "nsThreadUtils.h"
+#include "Units.h"
+#include "WinUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+#define PREF_DISPLAY_STATE \
+  "widget.windows.window_occlusion_tracking_display_state.enabled"
+#define PREF_SESSION_LOCK \
+  "widget.windows.window_occlusion_tracking_session_lock.enabled"
+
+class WinWindowOcclusionTrackerInteractiveTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    // Shut down WinWindowOcclusionTracker if it exists.
+    // This could happen when WinWindowOcclusionTracker was initialized by other
+    // gtest
+    if (WinWindowOcclusionTracker::Get()) {
+      WinWindowOcclusionTracker::ShutDown();
+    }
+    EXPECT_EQ(nullptr, WinWindowOcclusionTracker::Get());
+
+    WinWindowOcclusionTracker::Ensure();
+    EXPECT_NE(nullptr, WinWindowOcclusionTracker::Get());
+
+    WinWindowOcclusionTracker::Get()->EnsureDisplayStatusObserver();
+    WinWindowOcclusionTracker::Get()->EnsureSessionChangeObserver();
+  }
+
+  void TearDown() override {
+    WinWindowOcclusionTracker::ShutDown();
+    EXPECT_EQ(nullptr, WinWindowOcclusionTracker::Get());
+  }
+
+  void SetNativeWindowBounds(HWND aHWnd, const LayoutDeviceIntRect aBounds) {
+    RECT wr;
+    wr.left = aBounds.X();
+    wr.top = aBounds.Y();
+    wr.right = aBounds.XMost();
+    wr.bottom = aBounds.YMost();
+
+    ::AdjustWindowRectEx(&wr, ::GetWindowLong(aHWnd, GWL_STYLE), FALSE,
+                         ::GetWindowLong(aHWnd, GWL_EXSTYLE));
+
+    // Make sure to keep the window onscreen, as AdjustWindowRectEx() may have
+    // moved part of it offscreen. But, if the original requested bounds are
+    // offscreen, don't adjust the position.
+    LayoutDeviceIntRect windowBounds(wr.left, wr.top, wr.right - wr.left,
+                                     wr.bottom - wr.top);
+
+    if (aBounds.X() >= 0) {
+      windowBounds.x = std::max(0, windowBounds.X());
+    }
+    if (aBounds.Y() >= 0) {
+      windowBounds.y = std::max(0, windowBounds.Y());
+    }
+    ::SetWindowPos(aHWnd, HWND_TOP, windowBounds.X(), windowBounds.Y(),
+                   windowBounds.Width(), windowBounds.Height(),
+                   SWP_NOREPOSITION);
+    EXPECT_TRUE(::UpdateWindow(aHWnd));
+  }
+
+  void CreateNativeWindowWithBounds(LayoutDeviceIntRect aBounds) {
+    mMockWinWidget = MockWinWidget::Create(
+        WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN, /* aExStyle = */ 0, aBounds);
+    EXPECT_NE(nullptr, mMockWinWidget.get());
+    HWND hwnd = mMockWinWidget->GetWnd();
+    SetNativeWindowBounds(hwnd, aBounds);
+    HRGN region = ::CreateRectRgn(0, 0, 0, 0);
+    EXPECT_NE(nullptr, region);
+    if (::GetWindowRgn(hwnd, region) == COMPLEXREGION) {
+      // On Windows 7, the newly created window has a complex region, which
+      // means it will be ignored during the occlusion calculation. So, force
+      // it to have a simple region so that we get test coverage on win 7.
+      RECT boundingRect;
+      EXPECT_TRUE(::GetWindowRect(hwnd, &boundingRect));
+      HRGN rectangularRegion = ::CreateRectRgnIndirect(&boundingRect);
+      EXPECT_NE(nullptr, rectangularRegion);
+      ::SetWindowRgn(hwnd, rectangularRegion, /* bRedraw = */ TRUE);
+      ::DeleteObject(rectangularRegion);
+    }
+    ::DeleteObject(region);
+
+    ::ShowWindow(hwnd, SW_SHOWNORMAL);
+    EXPECT_TRUE(UpdateWindow(hwnd));
+  }
+
+  RefPtr<MockWinWidget> CreateTrackedWindowWithBounds(
+      LayoutDeviceIntRect aBounds) {
+    RefPtr<MockWinWidget> window = MockWinWidget::Create(
+        WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN, /* aExStyle */ 0, aBounds);
+    EXPECT_NE(nullptr, window.get());
+    HWND hwnd = window->GetWnd();
+    ::ShowWindow(hwnd, SW_SHOWNORMAL);
+    WinWindowOcclusionTracker::Get()->Enable(window, window->GetWnd());
+    return window;
+  }
+
+  int GetNumVisibleRootWindows() {
+    return WinWindowOcclusionTracker::Get()->mNumVisibleRootWindows;
+  }
+
+  void OnDisplayStateChanged(bool aDisplayOn) {
+    WinWindowOcclusionTracker::Get()->OnDisplayStateChanged(aDisplayOn);
+  }
+
+  RefPtr<MockWinWidget> mMockWinWidget;
+};
+
+// Simple test completely covering a tracked window with a native window.
+TEST_F(WinWindowOcclusionTrackerInteractiveTest, SimpleOcclusion) {
+  RefPtr<MockWinWidget> window =
+      CreateTrackedWindowWithBounds(LayoutDeviceIntRect(0, 0, 100, 100));
+  window->SetExpectation(widget::OcclusionState::OCCLUDED);
+  CreateNativeWindowWithBounds(LayoutDeviceIntRect(0, 0, 100, 100));
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+  EXPECT_FALSE(window->IsExpectingCall());
+}
+
+// Simple test partially covering a tracked window with a native window.
+TEST_F(WinWindowOcclusionTrackerInteractiveTest, PartialOcclusion) {
+  RefPtr<MockWinWidget> window =
+      CreateTrackedWindowWithBounds(LayoutDeviceIntRect(0, 0, 200, 200));
+  window->SetExpectation(widget::OcclusionState::VISIBLE);
+  CreateNativeWindowWithBounds(LayoutDeviceIntRect(0, 0, 50, 50));
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+  EXPECT_FALSE(window->IsExpectingCall());
+}
+
+// Simple test that a partly off screen tracked window, with the on screen part
+// occluded by a native window, is considered occluded.
+TEST_F(WinWindowOcclusionTrackerInteractiveTest, OffscreenOcclusion) {
+  RefPtr<MockWinWidget> window =
+      CreateTrackedWindowWithBounds(LayoutDeviceIntRect(0, 0, 100, 100));
+  // Move the tracked window 50 pixels offscreen to the left.
+  int screenLeft = ::GetSystemMetrics(SM_XVIRTUALSCREEN);
+  ::SetWindowPos(window->GetWnd(), HWND_TOP, screenLeft - 50, 0, 100, 100,
+                 SWP_NOZORDER | SWP_NOSIZE);
+
+  // Create a native window that covers the onscreen part of the tracked window.
+  CreateNativeWindowWithBounds(LayoutDeviceIntRect(screenLeft, 0, 50, 100));
+  window->SetExpectation(widget::OcclusionState::OCCLUDED);
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+  EXPECT_FALSE(window->IsExpectingCall());
+}
+
+// Simple test with a tracked window and native window that do not overlap.
+TEST_F(WinWindowOcclusionTrackerInteractiveTest, SimpleVisible) {
+  RefPtr<MockWinWidget> window =
+      CreateTrackedWindowWithBounds(LayoutDeviceIntRect(0, 0, 100, 100));
+  window->SetExpectation(widget::OcclusionState::VISIBLE);
+  CreateNativeWindowWithBounds(LayoutDeviceIntRect(200, 0, 100, 100));
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+  EXPECT_FALSE(window->IsExpectingCall());
+}
+
+// Simple test with a minimized tracked window and native window.
+TEST_F(WinWindowOcclusionTrackerInteractiveTest, SimpleHidden) {
+  RefPtr<MockWinWidget> window =
+      CreateTrackedWindowWithBounds(LayoutDeviceIntRect(0, 0, 100, 100));
+  CreateNativeWindowWithBounds(LayoutDeviceIntRect(200, 0, 100, 100));
+  // Iconify the tracked window and check that its occlusion state is HIDDEN.
+  ::CloseWindow(window->GetWnd());
+  window->SetExpectation(widget::OcclusionState::HIDDEN);
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+  EXPECT_FALSE(window->IsExpectingCall());
+}
+
+// Test that minimizing and restoring a tracked window results in the occlusion
+// tracker re-registering for win events and detecting that a native window
+// occludes the tracked window.
+TEST_F(WinWindowOcclusionTrackerInteractiveTest,
+       OcclusionAfterVisibilityToggle) {
+  RefPtr<MockWinWidget> window =
+      CreateTrackedWindowWithBounds(LayoutDeviceIntRect(0, 0, 100, 100));
+  window->SetExpectation(widget::OcclusionState::VISIBLE);
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+
+  window->SetExpectation(widget::OcclusionState::HIDDEN);
+  WinWindowOcclusionTracker::Get()->OnWindowVisibilityChanged(
+      window, /* aVisible = */ false);
+
+  // This makes the window iconic.
+  ::CloseWindow(window->GetWnd());
+
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+
+  // HIDDEN state is set synchronously by OnWindowVsiblityChanged notification,
+  // before occlusion is calculated, so the above expectation will be met w/o an
+  // occlusion calculation.
+  // Loop until an occlusion calculation has run with no non-hidden windows.
+  while (GetNumVisibleRootWindows() != 0) {
+    // Need to pump events in order for UpdateOcclusionState to get called, and
+    // update the number of non hidden windows. When that number is 0,
+    // occlusion has been calculated with no visible tracked windows.
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+
+  window->SetExpectation(widget::OcclusionState::VISIBLE);
+  WinWindowOcclusionTracker::Get()->OnWindowVisibilityChanged(
+      window, /* aVisible = */ true);
+  // This opens the window made iconic above.
+  ::OpenIcon(window->GetWnd());
+
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+
+  // Open a native window that occludes the visible tracked window.
+  window->SetExpectation(widget::OcclusionState::OCCLUDED);
+  CreateNativeWindowWithBounds(LayoutDeviceIntRect(0, 0, 100, 100));
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+  EXPECT_FALSE(window->IsExpectingCall());
+}
+
+// Test that locking the screen causes visible windows to become occluded.
+TEST_F(WinWindowOcclusionTrackerInteractiveTest, LockScreenVisibleOcclusion) {
+  RefPtr<MockWinWidget> window =
+      CreateTrackedWindowWithBounds(LayoutDeviceIntRect(0, 0, 100, 100));
+  window->SetExpectation(widget::OcclusionState::VISIBLE);
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+
+  window->SetExpectation(widget::OcclusionState::OCCLUDED);
+  // Unfortunately, this relies on knowing that NativeWindowOcclusionTracker
+  // uses SessionChangeObserver to listen for WM_WTSSESSION_CHANGE messages, but
+  // actually locking the screen isn't feasible.
+  DWORD currentSessionId = 0;
+  ::ProcessIdToSessionId(::GetCurrentProcessId(), &currentSessionId);
+  ::PostMessage(WinEventHub::Get()->GetWnd(), WM_WTSSESSION_CHANGE,
+                WTS_SESSION_LOCK, currentSessionId);
+
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+
+    MSG msg;
+    bool gotMessage =
+        ::PeekMessageW(&msg, WinEventHub::Get()->GetWnd(), 0, 0, PM_REMOVE);
+    if (gotMessage) {
+      ::TranslateMessage(&msg);
+      ::DispatchMessageW(&msg);
+    }
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ false);
+    PR_Sleep(PR_INTERVAL_NO_WAIT);
+  }
+  EXPECT_FALSE(window->IsExpectingCall());
+}
+
+// Test that locking the screen leaves hidden windows as hidden.
+TEST_F(WinWindowOcclusionTrackerInteractiveTest, LockScreenHiddenOcclusion) {
+  RefPtr<MockWinWidget> window =
+      CreateTrackedWindowWithBounds(LayoutDeviceIntRect(0, 0, 100, 100));
+  // Iconify the tracked window and check that its occlusion state is HIDDEN.
+  ::CloseWindow(window->GetWnd());
+  window->SetExpectation(widget::OcclusionState::HIDDEN);
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+
+  // Force the state to VISIBLE.
+  window->NotifyOcclusionState(widget::OcclusionState::VISIBLE);
+
+  window->SetExpectation(widget::OcclusionState::HIDDEN);
+
+  // Unfortunately, this relies on knowing that NativeWindowOcclusionTracker
+  // uses SessionChangeObserver to listen for WM_WTSSESSION_CHANGE messages, but
+  // actually locking the screen isn't feasible.
+  DWORD currentSessionId = 0;
+  ::ProcessIdToSessionId(::GetCurrentProcessId(), &currentSessionId);
+  PostMessage(WinEventHub::Get()->GetWnd(), WM_WTSSESSION_CHANGE,
+              WTS_SESSION_LOCK, currentSessionId);
+
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+
+    MSG msg;
+    bool gotMessage =
+        ::PeekMessageW(&msg, WinEventHub::Get()->GetWnd(), 0, 0, PM_REMOVE);
+    if (gotMessage) {
+      ::TranslateMessage(&msg);
+      ::DispatchMessageW(&msg);
+    }
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ false);
+    PR_Sleep(PR_INTERVAL_NO_WAIT);
+  }
+  EXPECT_FALSE(window->IsExpectingCall());
+}
+
+// Test that locking the screen from a different session doesn't mark window
+// as occluded.
+TEST_F(WinWindowOcclusionTrackerInteractiveTest, LockScreenDifferentSession) {
+  RefPtr<MockWinWidget> window =
+      CreateTrackedWindowWithBounds(LayoutDeviceIntRect(0, 0, 200, 200));
+  window->SetExpectation(widget::OcclusionState::VISIBLE);
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+
+  // Force the state to OCCLUDED.
+  window->NotifyOcclusionState(widget::OcclusionState::OCCLUDED);
+
+  // Generate a session change lock screen with a session id that's not
+  // currentSessionId.
+  DWORD currentSessionId = 0;
+  ::ProcessIdToSessionId(::GetCurrentProcessId(), &currentSessionId);
+  ::PostMessage(WinEventHub::Get()->GetWnd(), WM_WTSSESSION_CHANGE,
+                WTS_SESSION_LOCK, currentSessionId + 1);
+
+  window->SetExpectation(widget::OcclusionState::VISIBLE);
+  // Create a native window to trigger occlusion calculation.
+  CreateNativeWindowWithBounds(LayoutDeviceIntRect(0, 0, 50, 50));
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+
+    MSG msg;
+    bool gotMessage =
+        ::PeekMessageW(&msg, WinEventHub::Get()->GetWnd(), 0, 0, PM_REMOVE);
+    if (gotMessage) {
+      ::TranslateMessage(&msg);
+      ::DispatchMessageW(&msg);
+    }
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ false);
+    PR_Sleep(PR_INTERVAL_NO_WAIT);
+  }
+  EXPECT_FALSE(window->IsExpectingCall());
+}
+
+// Test that display off & on power state notification causes visible windows to
+// become occluded, then visible.
+TEST_F(WinWindowOcclusionTrackerInteractiveTest, DisplayOnOffHandling) {
+  RefPtr<MockWinWidget> window =
+      CreateTrackedWindowWithBounds(LayoutDeviceIntRect(0, 0, 100, 100));
+  window->SetExpectation(widget::OcclusionState::VISIBLE);
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+
+  window->SetExpectation(widget::OcclusionState::OCCLUDED);
+
+  // Turning display off and on isn't feasible, so send a notification.
+  OnDisplayStateChanged(/* aDisplayOn */ false);
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+
+  window->SetExpectation(widget::OcclusionState::VISIBLE);
+  OnDisplayStateChanged(/* aDisplayOn */ true);
+  while (window->IsExpectingCall()) {
+    WinWindowOcclusionTracker::Get()->TriggerCalculation();
+
+    NS_ProcessNextEvent(nullptr, /* aMayWait = */ true);
+  }
+  EXPECT_FALSE(window->IsExpectingCall());
+}
diff --git a/widget/tests/gtest/moz.build b/widget/tests/gtest/moz.build
new file mode 100644
index 0000000000..613844fa78
--- /dev/null
+++ b/widget/tests/gtest/moz.build
@@ -0,0 +1,27 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at http://mozilla.org/MPL/2.0/.
+
+UNIFIED_SOURCES = [
+    "TestTimeConverter.cpp",
+    "TestTouchResampler.cpp",
+]
+
+if CONFIG["OS_ARCH"] == "WINNT":
+    UNIFIED_SOURCES += [
+        "MockWinWidget.cpp",
+        "TestWinHeaderOnlyUtils.cpp",
+        "TestWinMessageLoggingUtils.cpp",
+        "TestWinWindowOcclusionTracker.cpp",
+        "TestWinWindowOcclusionTrackerInteractive.cpp",
+    ]
+
+FINAL_LIBRARY = "xul-gtest"
+
+LOCAL_INCLUDES += [
+    "/widget",
+]
+
+DisableStlWrapping()
diff --git a/widget/tests/mochitest.toml b/widget/tests/mochitest.toml
new file mode 100644
index 0000000000..32dcf5c795
--- /dev/null
+++ b/widget/tests/mochitest.toml
@@ -0,0 +1,53 @@
+[DEFAULT]
+support-files = ["clipboard_helper.js"]
+
+["test_AltGr_key_events_in_web_content_on_windows.html"]
+run-if = ["os == 'win'"]
+skip-if = ["headless"] # bug 1410525
+
+["test_actionhint.html"]
+
+["test_assign_event_data.html"]
+skip-if = [
+  "os == 'mac'", # bug 933303
+  "os == 'android' && debug", # bug 1285414
+  "android_version == '24'",
+  "headless && os == 'win'",
+]
+
+["test_autocapitalize.html"]
+
+["test_clipboard.html"]
+skip-if = [
+  "headless", # bug 1852983
+  "display == 'wayland' && os_version == '22.04'",  # Bug 1857075
+]
+support-files = ["file_test_clipboard.js"]
+
+["test_clipboard_asyncGetData.html"]
+skip-if = ["display == 'wayland'"] # Bug 1864211
+support-files = ["file_test_clipboard_asyncGetData.js"]
+
+["test_clipboard_asyncSetData.html"]
+support-files = ["file_test_clipboard_asyncSetData.js"]
+
+["test_contextmenu_by_mouse_on_unix.html"]
+run-if = ["os == 'linux'"]
+skip-if = ["headless"] # headless widget doesn't dispatch contextmenu event by mouse event.
+
+["test_keypress_event_with_alt_on_mac.html"]
+run-if = ["os == 'mac'"]
+
+["test_mouse_event_with_control_on_mac.html"]
+run-if = ["os == 'mac'"]
+support-files = ["!/gfx/layers/apz/test/mochitest/apz_test_utils.js"]
+
+["test_picker_no_crash.html"]
+skip-if = [
+  "asan",
+  "debug", # bug 1267491
+]
+support-files = ["window_picker_no_crash_child.html"]
+
+["test_textScaleFactor_system_font.html"]
+skip-if = ["display == 'wayland' && os_version == '22.04'"]  # Bug 1857075
diff --git a/widget/tests/moz.build b/widget/tests/moz.build
new file mode 100644
index 0000000000..fe0d068efd
--- /dev/null
+++ b/widget/tests/moz.build
@@ -0,0 +1,125 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "Widget")
+
+with Files("browser/browser_test_ContentCache.html"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("unit/*macwebapputils*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("unit/*taskbar_jumplistitems*"):
+    BUG_COMPONENT = ("Core", "Widget: Win32")
+
+with Files("TestChromeMargin.cpp"):
+    BUG_COMPONENT = ("Core", "Widget: Win32")
+
+with Files("*413277*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*428405*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*429954*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*444800*"):
+    BUG_COMPONENT = ("Core", "Widget: Win32")
+
+with Files("*466599*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*478536*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*485118*"):
+    BUG_COMPONENT = ("Toolkit", "UI Widgets")
+
+with Files("*517396*"):
+    BUG_COMPONENT = ("Toolkit", "UI Widgets")
+
+with Files("*522217*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*538242*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*565392*"):
+    BUG_COMPONENT = ("Core", "DOM: Serializers")
+
+with Files("*586713*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*593307*"):
+    BUG_COMPONENT = ("Core", "Widget: Win32")
+
+with Files("*596600*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*673301*"):
+    BUG_COMPONENT = ("Firefox", "Bookmarks & History")
+
+with Files("test_assign_event_data.html"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("test_input_events_on_deactive_window.xhtml"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*chrome_context_menus_win*"):
+    BUG_COMPONENT = ("Core", "General")
+
+with Files("*composition_text_querycontent*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*key_event_counts*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*imestate*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*mouse_scroll*"):
+    BUG_COMPONENT = ("Core", "Widget: Win32")
+
+with Files("*native*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*panel_mouse_coords*"):
+    BUG_COMPONENT = ("Core", "Widget: Gtk")
+
+with Files("*picker_no_crash*"):
+    BUG_COMPONENT = ("Core", "Widget: Win32")
+
+with Files("*platform_colors*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*position_on_resize*"):
+    BUG_COMPONENT = ("Core", "Widget: Gtk")
+
+with Files("test_sizemode_events.xhtml"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*system_status_bar*"):
+    BUG_COMPONENT = ("Core", "Widget: Cocoa")
+
+with Files("*taskbar_progress*"):
+    BUG_COMPONENT = ("Core", "Widget: Win32")
+
+with Files("*wheeltransaction*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+
+XPCSHELL_TESTS_MANIFESTS += ["unit/xpcshell.toml"]
+MOCHITEST_MANIFESTS += ["mochitest.toml"]
+MOCHITEST_CHROME_MANIFESTS += ["chrome.toml"]
+BROWSER_CHROME_MANIFESTS += ["browser/browser.toml"]
+
+# if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'windows':
+#
+#     Test disabled because it requires the internal API. Re-enabling this test
+#     is bug 652123.
+#     CPP_UNIT_TESTS += ['TestChromeMargin']
diff --git a/widget/tests/native_menus_window.xhtml b/widget/tests/native_menus_window.xhtml
new file mode 100644
index 0000000000..2b3d3f2aa3
--- /dev/null
+++ b/widget/tests/native_menus_window.xhtml
@@ -0,0 +1,282 @@
+<?xml version="1.0"?>
+
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+
+<window id="NativeMenuWindow"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        width="300"
+        height="300"
+        onload="onLoad();"
+        title="Native Menu Test">
+
+  <command id="cmd_FooItem0" oncommand="executedCommandID = 'cmd_FooItem0';"/>
+  <command id="cmd_FooItem1" oncommand="executedCommandID = 'cmd_FooItem1';"/>
+  <command id="cmd_BarItem0" oncommand="executedCommandID = 'cmd_BarItem0';"/>
+  <command id="cmd_BarItem1" oncommand="executedCommandID = 'cmd_BarItem1';"/>
+  <command id="cmd_NewItem0" oncommand="executedCommandID = 'cmd_NewItem0';"/>
+  <command id="cmd_NewItem1" oncommand="executedCommandID = 'cmd_NewItem1';"/>
+  <command id="cmd_NewItem2" oncommand="executedCommandID = 'cmd_NewItem2';"/>
+  <command id="cmd_NewItem3" oncommand="executedCommandID = 'cmd_NewItem3';"/>
+  <command id="cmd_NewItem4" oncommand="executedCommandID = 'cmd_NewItem4';"/>
+  <command id="cmd_NewItem5" oncommand="executedCommandID = 'cmd_NewItem5';"/>
+
+  <!-- We do not modify any menus or menu items defined here in testing. These
+       serve as a baseline structure for us to test after other modifications.
+       We add children to the menubar defined here and test by modifying those
+       children. -->
+  <menubar id="nativemenubar">
+    <menu id="foo" label="Foo">
+      <menupopup>
+        <menuitem label="FooItem0" command="cmd_FooItem0"/>
+        <menuitem label="FooItem1" command="cmd_FooItem1"/>
+        <menuseparator/>
+        <menu label="Bar">
+          <menupopup>
+            <menuitem label="BarItem0" command="cmd_BarItem0"/>
+            <menuitem label="BarItem1" command="cmd_BarItem1"/>
+          </menupopup>
+        </menu>
+      </menupopup>
+    </menu>
+  </menubar>
+
+  <script type="application/javascript"><![CDATA[
+
+    function ok(condition, message) {
+      window.arguments[0].SimpleTest.ok(condition, message);
+    }
+
+    function onTestsFinished() {
+      window.close();
+      window.arguments[0].SimpleTest.finish();
+    }
+
+    // Force a menu to update itself. All of the menus parents will be updated
+    // as well. An empty string will force a complete menu system reload.
+    function forceUpdateNativeMenuAt(location) {
+      var utils = window.windowUtils;
+      try {
+        utils.forceUpdateNativeMenuAt(location);
+      }
+      catch (e) {
+        dump(e + "\n");
+      }
+    }
+
+    var executedCommandID = "";
+
+    function testItem(location, targetID) {
+      var utils = window.windowUtils;
+      var correctCommandHandler = false;
+      try {
+        utils.activateNativeMenuItemAt(location);
+        correctCommandHandler = executedCommandID == targetID;
+      }
+      catch (e) {
+        dump(e + "\n");
+      }
+      finally {
+        executedCommandID = "";
+      }
+      return correctCommandHandler;
+    }
+
+    function createXULMenuPopup() {
+      const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+      var item = document.createElementNS(XUL_NS, "menupopup");
+      return item;
+    }
+
+    function createXULMenu(aLabel) {
+      const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+      var item = document.createElementNS(XUL_NS, "menu");
+      item.setAttribute("label", aLabel);
+      return item;
+    }
+
+    function createXULMenuItem(aLabel, aCommandId) {
+      const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+      var item = document.createElementNS(XUL_NS, "menuitem");
+      item.setAttribute("label", aLabel);
+      item.setAttribute("command", aCommandId);
+      return item;
+    }
+
+    function runBaseMenuTests() {
+      forceUpdateNativeMenuAt("0|3");
+      return testItem("0|0", "cmd_FooItem0") &&
+             testItem("0|1", "cmd_FooItem1") &&
+             testItem("0|3|0", "cmd_BarItem0") &&
+             testItem("0|3|1", "cmd_BarItem1");
+    }
+
+    function onLoad() {
+      var _delayedOnLoad = function() {
+        // First let's run the base menu tests.
+        ok(runBaseMenuTests());
+
+        // Set up some nodes that we'll use.
+        var menubarNode = document.getElementById("nativemenubar");
+        var newMenu0 = createXULMenu("NewMenu0");
+        var newMenu1 = createXULMenu("NewMenu1");
+        var newMenuPopup0 = createXULMenuPopup();
+        var newMenuPopup1 = createXULMenuPopup();
+        var newMenuItem0 = createXULMenuItem("NewMenuItem0", "cmd_NewItem0");
+        var newMenuItem1 = createXULMenuItem("NewMenuItem1", "cmd_NewItem1");
+        var newMenuItem2 = createXULMenuItem("NewMenuItem2", "cmd_NewItem2");
+        var newMenuItem3 = createXULMenuItem("NewMenuItem3", "cmd_NewItem3");
+        var newMenuItem4 = createXULMenuItem("NewMenuItem4", "cmd_NewItem4");
+        var newMenuItem5 = createXULMenuItem("NewMenuItem5", "cmd_NewItem5");
+
+        // Create another submenu with hierarchy via DOM manipulation.
+        // ******************
+        // * Foo * NewMenu0 * <- Menu bar 
+        // ******************
+        //       ****************
+        //       * NewMenuItem0 * <- NewMenu0 submenu
+        //       ****************
+        //       * NewMenuItem1 *
+        //       ****************
+        //       * NewMenuItem2 *
+        //       *******************************
+        //       * NewMenu1   > * NewMenuItem3 * <- NewMenu1 submenu
+        //       *******************************
+        //                      * NewMenuItem4 *
+        //                      ****************
+        //                      * NewMenuItem5 *
+        //                      ****************
+        newMenu0.appendChild(newMenuPopup0);
+        newMenuPopup0.appendChild(newMenuItem0);
+        newMenuPopup0.appendChild(newMenuItem1);
+        newMenuPopup0.appendChild(newMenuItem2);
+        newMenuPopup0.appendChild(newMenu1);
+        newMenu1.appendChild(newMenuPopup1);
+        newMenuPopup1.appendChild(newMenuItem3);
+        newMenuPopup1.appendChild(newMenuItem4);
+        newMenuPopup1.appendChild(newMenuItem5);
+        //XXX - we have to append the menu to the top-level of the menu bar
+        // only after constructing it. If we append before construction, it is
+        // invalid because it has no children and we don't validate it if we add
+        // children later.
+        menubarNode.appendChild(newMenu0);
+        forceUpdateNativeMenuAt("1|3");
+        // Run basic tests again.
+        ok(runBaseMenuTests());
+
+        // Error strings.
+        var sa = "Command handler(s) should have activated";
+        var sna = "Command handler(s) should not have activated";
+
+        // Test middle items.
+        ok(testItem("1|1", "cmd_NewItem1"), sa);
+        ok(testItem("1|3|1", "cmd_NewItem4"), sa);
+
+        // Hide newMenu0.
+        newMenu0.setAttribute("hidden", "true");
+        ok(runBaseMenuTests(), sa); // the base menu should still be unhidden
+        ok(!testItem("1|0", ""), sna);
+        ok(!testItem("1|1", ""), sna);
+        ok(!testItem("1|2", ""), sna);
+        ok(!testItem("1|3|0", ""), sna);
+        ok(!testItem("1|3|1", ""), sna);
+        ok(!testItem("1|3|2", ""), sna);
+
+        // Show newMenu0.
+        newMenu0.setAttribute("hidden", "false");
+        forceUpdateNativeMenuAt("1|3");
+        ok(runBaseMenuTests(), sa);
+        ok(testItem("1|0", "cmd_NewItem0"), sa);
+        ok(testItem("1|1", "cmd_NewItem1"), sa);
+        ok(testItem("1|2", "cmd_NewItem2"), sa);
+        ok(testItem("1|3|0", "cmd_NewItem3"), sa);
+        ok(testItem("1|3|1", "cmd_NewItem4"), sa);
+        ok(testItem("1|3|2", "cmd_NewItem5"), sa);
+
+        // Hide items.
+        newMenuItem1.setAttribute("hidden", "true");
+        newMenuItem4.setAttribute("hidden", "true");
+        forceUpdateNativeMenuAt("1|2");
+        ok(runBaseMenuTests(), sa);
+        ok(testItem("1|0", "cmd_NewItem0"), sa);
+        ok(testItem("1|1", "cmd_NewItem2"), sa);
+        ok(!testItem("1|2", ""), sna);
+        ok(testItem("1|2|0", "cmd_NewItem3"), sa);
+        ok(testItem("1|2|1", "cmd_NewItem5"), sa);
+        ok(!testItem("1|2|2", ""), sna);
+
+        // Show items.
+        newMenuItem1.setAttribute("hidden", "false");
+        newMenuItem4.setAttribute("hidden", "false");
+        forceUpdateNativeMenuAt("1|3");
+        ok(runBaseMenuTests(), sa);
+        ok(testItem("1|0", "cmd_NewItem0"), sa);
+        ok(testItem("1|1", "cmd_NewItem1"), sa);
+        ok(testItem("1|2", "cmd_NewItem2"), sa);
+        ok(testItem("1|3|0", "cmd_NewItem3"), sa);
+        ok(testItem("1|3|1", "cmd_NewItem4"), sa);
+        ok(testItem("1|3|2", "cmd_NewItem5"), sa);
+
+        // At this point in the tests the state of the menus has been returned
+        // to the originally diagramed state.
+
+        // Test command disabling
+        var cmd_NewItem0 = document.getElementById("cmd_NewItem0");
+        ok(testItem("1|0", "cmd_NewItem0"), sa);
+        cmd_NewItem0.setAttribute("disabled", "true");
+        ok(!testItem("1|0", "cmd_NewItem0"), sna);
+        cmd_NewItem0.removeAttribute("disabled");
+        ok(testItem("1|0", "cmd_NewItem0"), sa);
+
+        // Remove menu.
+        menubarNode.removeChild(newMenu0);
+        ok(runBaseMenuTests(), sa);
+        ok(!testItem("1|0", ""), sna);
+        ok(!testItem("1|1", ""), sna);
+        ok(!testItem("1|2", ""), sna);
+        ok(!testItem("1|3|0", ""), sna);
+        ok(!testItem("1|3|1", ""), sna);
+        ok(!testItem("1|3|2", ""), sna);
+        // return state to original diagramed state
+        menubarNode.appendChild(newMenu0);
+
+        // Test for bug 447042, make sure that adding a menu node with no children
+        // to the menu bar and then adding another menu node with children works.
+        // Menus with no children don't get their native menu items shown and that
+        // caused internal arrays to get out of sync and an append crashed.
+        var tmpMenu0 = createXULMenu("tmpMenu0");
+        menubarNode.removeChild(newMenu0);
+        menubarNode.appendChild(tmpMenu0);
+        menubarNode.appendChild(newMenu0);
+        forceUpdateNativeMenuAt("1|3");
+        ok(runBaseMenuTests());
+        ok(testItem("1|0", "cmd_NewItem0"), sa);
+        ok(testItem("1|1", "cmd_NewItem1"), sa);
+        ok(testItem("1|2", "cmd_NewItem2"), sa);
+        ok(testItem("1|3|0", "cmd_NewItem3"), sa);
+        ok(testItem("1|3|1", "cmd_NewItem4"), sa);
+        ok(testItem("1|3|2", "cmd_NewItem5"), sa);
+        // return state to original diagramed state
+        menubarNode.removeChild(tmpMenu0);
+
+        // This test is basically a crash test for bug 433858.
+        newMenuItem1.setAttribute("hidden", "true");
+        newMenuItem2.setAttribute("hidden", "true");
+        newMenu1.setAttribute("hidden", "true");
+        forceUpdateNativeMenuAt("1");
+        newMenuItem1.setAttribute("hidden", "false");
+        newMenuItem2.setAttribute("hidden", "false");
+        newMenu1.setAttribute("hidden", "false");
+        forceUpdateNativeMenuAt("1");
+
+        onTestsFinished();
+      }
+
+      setTimeout(_delayedOnLoad, 1000);
+    }
+
+  ]]></script>
+</window>
diff --git a/widget/tests/standalone_native_menu_window.xhtml b/widget/tests/standalone_native_menu_window.xhtml
new file mode 100644
index 0000000000..4155126ad5
--- /dev/null
+++ b/widget/tests/standalone_native_menu_window.xhtml
@@ -0,0 +1,374 @@
+<?xml version="1.0"?>
+
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+
+<window id="StandaloneNativeMenuWindow"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        width="300"
+        height="300"
+        onload="onLoad();"
+        title="nsIStandaloneNativeMenu Test">
+
+  <command id="cmd_FooItem0" oncommand="gExecutedCommandID = 'cmd_FooItem0';"/>
+  <command id="cmd_FooItem1" oncommand="gExecutedCommandID = 'cmd_FooItem1';"/>
+  <command id="cmd_BarItem0" oncommand="gExecutedCommandID = 'cmd_BarItem0';"/>
+  <command id="cmd_BarItem1" oncommand="gExecutedCommandID = 'cmd_BarItem1';"/>
+  <command id="cmd_NewItem0" oncommand="gExecutedCommandID = 'cmd_NewItem0';"/>
+  <command id="cmd_NewItem1" oncommand="gExecutedCommandID = 'cmd_NewItem1';"/>
+  <command id="cmd_NewItem2" oncommand="gExecutedCommandID = 'cmd_NewItem2';"/>
+  <command id="cmd_NewItem3" oncommand="gExecutedCommandID = 'cmd_NewItem3';"/>
+  <command id="cmd_NewItem4" oncommand="gExecutedCommandID = 'cmd_NewItem4';"/>
+  <command id="cmd_NewItem5" oncommand="gExecutedCommandID = 'cmd_NewItem5';"/>
+
+  <!-- We do not modify any menus or menu items defined here in testing. These
+       serve as a baseline structure for us to test after other modifications.
+       We add children to the menubar defined here and test by modifying those
+       children. -->
+  <popupset>
+    <menupopup id="standalonenativemenu">
+      <menu id="foo" label="Foo">
+        <menupopup>
+          <menuitem label="FooItem0" command="cmd_FooItem0"/>
+          <menuitem label="FooItem1" command="cmd_FooItem1"/>
+          <menuseparator/>
+          <menu label="Bar">
+            <menupopup>
+              <menuitem label="BarItem0" command="cmd_BarItem0"/>
+              <menuitem label="BarItem1" command="cmd_BarItem1"/>
+            </menupopup>
+          </menu>
+        </menupopup>
+      </menu>
+    </menupopup>
+  </popupset>
+
+  <script type="application/javascript"><![CDATA[
+
+    function ok(condition, message) {
+      window.arguments[0].SimpleTest.ok(condition, message);
+    }
+
+    function is(a, b, message) {
+      window.arguments[0].SimpleTest.is(a, b, message);
+    }
+
+    function isnot(a, b, message) {
+      window.arguments[0].SimpleTest.isnot(a, b, message);
+    }
+
+    function todo(condition, message) {
+      window.arguments[0].SimpleTest.todo(condition, message);
+    }
+
+    function todo_is(a, b, message) {
+      window.arguments[0].SimpleTest.todo_is(a, b, message);
+    }
+
+    function todo_isnot(a, b, message) {
+      window.arguments[0].SimpleTest.todo_isnot(a, b, message);
+    }
+
+    function onTestsFinished() {
+      window.close();
+      window.arguments[0].SimpleTest.finish();
+    }
+
+    var gExecutedCommandID;
+
+    // returns the executed command ID, or the empty string if nothing was executed
+    function activateItem(menu, location) {
+      try {
+        gExecutedCommandID = "";
+        menu.menuWillOpen();
+        menu.activateNativeMenuItemAt(location);
+        return gExecutedCommandID;
+      }
+      catch (e) {
+        // activateNativeMenuItemAt throws an exception if the item was not found
+        dump(e + "\n");
+        return "";
+      }
+    }
+
+    function testItem(menu, location, targetID) {
+      var activatedCommandID = activateItem(menu, location);
+      return activatedCommandID != "" && activatedCommandID == targetID;
+    }
+
+    var XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+
+    function createXULMenuPopup() {
+      return document.createElementNS(XUL_NS, "menupopup");
+    }
+
+    function createXULMenu(aLabel) {
+      var item = document.createElementNS(XUL_NS, "menu");
+      item.setAttribute("label", aLabel);
+      return item;
+    }
+
+    function createXULMenuItem(aLabel, aCommandId) {
+      var item = document.createElementNS(XUL_NS, "menuitem");
+      item.setAttribute("label", aLabel);
+      item.setAttribute("command", aCommandId);
+      return item;
+    }
+
+    function runBaseMenuTests(menu) {
+      menu.forceUpdateNativeMenuAt("0|3");
+      return testItem(menu, "0|0", "cmd_FooItem0") &&
+             testItem(menu, "0|1", "cmd_FooItem1") &&
+             testItem(menu, "0|3|0", "cmd_BarItem0") &&
+             testItem(menu, "0|3|1", "cmd_BarItem1");
+    }
+
+    function createStandaloneNativeMenu(menuNode) {
+      try {
+        let menu = Cc["@mozilla.org/widget/standalonenativemenu;1"].createInstance(Ci.nsIStandaloneNativeMenu);
+        menu.init(menuNode);
+        return menu;
+      } catch (e) {
+        ok(false, "Failed creating nsIStandaloneNativeMenu instance");
+        throw e;
+      }
+    }
+
+    function runDetachedMenuTests(addMenupopupBeforeCreatingSNM) {
+      let menu = createXULMenu("Detached menu");
+      menu.setAttribute("image", 'data:image/svg+xml,<svg%20xmlns="http://www.w3.org/2000/svg"%20width="32"%20height="32"><circle%20cx="16"%20cy="16"%20r="16"/></svg>');
+      let menupopup = createXULMenuPopup();
+
+      let popupShowingFired = false;
+      let itemActivated = false;
+
+      menupopup.addEventListener("popupshowing", function (e) {
+        popupShowingFired = true;
+
+        let menuitem = document.createElementNS(XUL_NS, "menuitem");
+        menuitem.setAttribute("label", "detached menu item");
+        /* eslint-disable-next-line no-shadow */
+        menuitem.addEventListener("command", function (e) {
+          itemActivated = true;
+        })
+        menupopup.appendChild(menuitem);
+      })
+
+      // It shouldn't make a difference whether the menupopup is added to the
+      // menu element before or after we create the nsIStandaloneNativeMenu
+      // instance with it. We test both orders by calling this function twice
+      // with different values for addMenupopupBeforeCreatingSNM.
+
+      var menuSNM = null; // the nsIStandaloneNativeMenu object for "menu"
+      if (addMenupopupBeforeCreatingSNM) {
+        menu.appendChild(menupopup);
+        menuSNM = createStandaloneNativeMenu(menu);
+      } else {
+        menuSNM = createStandaloneNativeMenu(menu);
+        menu.appendChild(menupopup);
+      }
+
+      try {
+        ok(!popupShowingFired, "popupshowing shouldn't have fired before our call to menuWillOpen()");
+        menuSNM.menuWillOpen();
+        ok(popupShowingFired, "calling menuWillOpen() should have notified our popupshowing listener");
+
+        ok(!itemActivated, "our dynamically-added menuitem shouldn't have been activated yet");
+        menuSNM.activateNativeMenuItemAt("0");
+        ok(itemActivated, "the new menu item should have been activated now");
+      } catch (ex) {
+        ok(false, "dynamic menu test failed: " + ex);
+      }
+    }
+
+    function onLoad() {
+      var _delayedOnLoad = function() {
+        try {
+
+        var menuNode = document.getElementById("standalonenativemenu");
+        var menu = createStandaloneNativeMenu(menuNode);
+
+        // First let's run the base menu tests.
+        ok(runBaseMenuTests(menu), "base tests #1");
+
+        // Set up some nodes that we'll use.
+        var newMenu0 = createXULMenu("NewMenu0");
+        var newMenu1 = createXULMenu("NewMenu1");
+        var newMenuPopup0 = createXULMenuPopup();
+        var newMenuPopup1 = createXULMenuPopup();
+        var newMenuItem0 = createXULMenuItem("NewMenuItem0", "cmd_NewItem0");
+        var newMenuItem1 = createXULMenuItem("NewMenuItem1", "cmd_NewItem1");
+        var newMenuItem2 = createXULMenuItem("NewMenuItem2", "cmd_NewItem2");
+        var newMenuItem3 = createXULMenuItem("NewMenuItem3", "cmd_NewItem3");
+        var newMenuItem4 = createXULMenuItem("NewMenuItem4", "cmd_NewItem4");
+        var newMenuItem5 = createXULMenuItem("NewMenuItem5", "cmd_NewItem5");
+
+        // Create another submenu with hierarchy via DOM manipulation.
+        // ******************
+        // * Foo * NewMenu0 * <- Menu bar
+        // ******************
+        //       ****************
+        //       * NewMenuItem0 * <- NewMenu0 submenu
+        //       ****************
+        //       * NewMenuItem1 *
+        //       ****************
+        //       * NewMenuItem2 *
+        //       *******************************
+        //       * NewMenu1   > * NewMenuItem3 * <- NewMenu1 submenu
+        //       *******************************
+        //                      * NewMenuItem4 *
+        //                      ****************
+        //                      * NewMenuItem5 *
+        //                      ****************
+        newMenu0.appendChild(newMenuPopup0);
+        newMenuPopup0.appendChild(newMenuItem0);
+        newMenuPopup0.appendChild(newMenuItem1);
+        newMenuPopup0.appendChild(newMenuItem2);
+        newMenuPopup0.appendChild(newMenu1);
+        newMenu1.appendChild(newMenuPopup1);
+        newMenuPopup1.appendChild(newMenuItem3);
+        newMenuPopup1.appendChild(newMenuItem4);
+        newMenuPopup1.appendChild(newMenuItem5);
+        //XXX - we have to append the menu to the top-level of the menu bar
+        // only after constructing it. If we append before construction, it is
+        // invalid because it has no children and we don't validate it if we add
+        // children later.
+        menuNode.appendChild(newMenu0);
+        menu.forceUpdateNativeMenuAt("1|3");
+        // Run basic tests again.
+        ok(runBaseMenuTests(menu), "base tests #2");
+
+        // Error strings.
+        var sa = "Command handler(s) should have activated";
+        var sna = "Command handler(s) should not have activated";
+
+        // Test middle items.
+        is(activateItem(menu, "1|1"), "cmd_NewItem1", "#1:" + sa);
+        is(activateItem(menu, "1|3|1"), "cmd_NewItem4", "#2:" + sa);
+
+        // Hide newMenu0.
+        newMenu0.setAttribute("hidden", "true");
+        ok(runBaseMenuTests(menu), "base tests #3: " + sa); // the base menu should still be unhidden
+        is(activateItem(menu, "1|0"), "", "#3:" + sna);
+        is(activateItem(menu, "1|1"), "", "#4:" + sna);
+        is(activateItem(menu, "1|2"), "", "#5:" + sna);
+        is(activateItem(menu, "1|3|0"), "", "#6:" + sna);
+        is(activateItem(menu, "1|3|1"), "", "#7:" + sna);
+        is(activateItem(menu, "1|3|2"), "", "#8:" + sna);
+
+        // Show newMenu0.
+        newMenu0.setAttribute("hidden", "false");
+        menu.forceUpdateNativeMenuAt("1|3");
+        ok(runBaseMenuTests(menu), "base tests #4:" + sa);
+        is(activateItem(menu, "1|0"), "cmd_NewItem0", "#9:" + sa);
+        is(activateItem(menu, "1|1"), "cmd_NewItem1", "#10:" + sa);
+        is(activateItem(menu, "1|2"), "cmd_NewItem2", "#11:" + sa);
+        is(activateItem(menu, "1|3|0"), "cmd_NewItem3", "#12:" + sa);
+        is(activateItem(menu, "1|3|1"), "cmd_NewItem4", "#13:" + sa);
+        is(activateItem(menu, "1|3|2"), "cmd_NewItem5", "#14:" + sa);
+
+        // Hide items.
+        newMenuItem1.setAttribute("hidden", "true");
+        newMenuItem4.setAttribute("hidden", "true");
+        menu.forceUpdateNativeMenuAt("1|2");
+        ok(runBaseMenuTests(menu), "base tests #5:" + sa);
+        is(activateItem(menu, "1|0"), "cmd_NewItem0", "#15:" + sa);
+        is(activateItem(menu, "1|1"), "cmd_NewItem2", "#16:" + sa);
+        is(activateItem(menu, "1|2"), "", "#17:" + sna);
+        is(activateItem(menu, "1|2|0"), "cmd_NewItem3", "#18:" + sa);
+        is(activateItem(menu, "1|2|1"), "cmd_NewItem5", "#19:" + sa);
+        is(activateItem(menu, "1|2|2"), "", "#20:" + sna);
+
+        // Show items.
+        newMenuItem1.setAttribute("hidden", "false");
+        newMenuItem4.setAttribute("hidden", "false");
+        //forceUpdateNativeMenuAt("1|3");
+        ok(runBaseMenuTests(menu), "base tests #6:" + sa);
+        is(activateItem(menu, "1|0"), "cmd_NewItem0", "#21:" + sa);
+        is(activateItem(menu, "1|1"), "cmd_NewItem1", "#22:" + sa);
+        is(activateItem(menu, "1|2"), "cmd_NewItem2", "#23:" + sa);
+        is(activateItem(menu, "1|3|0"), "cmd_NewItem3", "#24:" + sa);
+        is(activateItem(menu, "1|3|1"), "cmd_NewItem4", "#25:" + sa);
+        is(activateItem(menu, "1|3|2"), "cmd_NewItem5", "#26:" + sa);
+
+        // At this point in the tests the state of the menus has been returned
+        // to the originally diagramed state.
+
+        // Remove menu.
+        menuNode.removeChild(newMenu0);
+        ok(runBaseMenuTests(menu), "base tests #7:" + sa);
+        is(activateItem(menu, "1|0"), "", "#27:" + sna);
+        is(activateItem(menu, "1|1"), "", "#28:" + sna);
+        is(activateItem(menu, "1|2"), "", "#29:" + sna);
+        is(activateItem(menu, "1|3|0"), "", "#30:" + sna);
+        is(activateItem(menu, "1|3|1"), "", "#31:" + sna);
+        is(activateItem(menu, "1|3|2"), "", "#32:" + sna);
+        // return state to original diagramed state
+        menuNode.appendChild(newMenu0);
+
+        // The following is based on a similar test bug 447042 from the native
+        // menu bar test: Make sure that adding a menu node with no children
+        // to the menu bar and then adding another menu node with children works.
+        // In the menubar, root menus with no children are skipped - they're not
+        // visible in the menubar.
+        // Regular menus currently treat submenus without children differently:
+        // submenus without children *are* visible.
+        // We may want to change this in the future.
+        // After the mutation below we have the following root menu content:
+        //  - [0] Foo (with submenu)
+        //  - [1] tmpMenu0 (with empty submenu)
+        //  - [2] NewMenu0 (with submenu)
+        // Since the empty tmpMenu0 item is not skipped, NewMenu0 has index 2,
+        // so we use "2|..." below, rather than the "1|..." that's used in the
+        // menubar test.
+        var tmpMenu0 = createXULMenu("tmpMenu0");
+        menuNode.removeChild(newMenu0);
+        menuNode.appendChild(tmpMenu0);
+        menuNode.appendChild(newMenu0);
+        menu.forceUpdateNativeMenuAt("2|3");
+        ok(runBaseMenuTests(menu), "base tests #8");
+        is(activateItem(menu, "2|0"), "cmd_NewItem0", "#33:" + sa);
+        is(activateItem(menu, "2|1"), "cmd_NewItem1", "#34:" + sa);
+        is(activateItem(menu, "2|2"), "cmd_NewItem2", "#35:" + sa);
+        is(activateItem(menu, "2|3|0"), "cmd_NewItem3", "#36:" + sa);
+        is(activateItem(menu, "2|3|1"), "cmd_NewItem4", "#37:" + sa);
+        is(activateItem(menu, "2|3|2"), "cmd_NewItem5", "#38:" + sa);
+        // return state to original diagramed state
+        menuNode.removeChild(tmpMenu0);
+
+        // This test is basically a crash test for bug 433858.
+        newMenuItem1.setAttribute("hidden", "true");
+        newMenuItem2.setAttribute("hidden", "true");
+        newMenu1.setAttribute("hidden", "true");
+        menu.forceUpdateNativeMenuAt("1");
+        newMenuItem1.setAttribute("hidden", "false");
+        newMenuItem2.setAttribute("hidden", "false");
+        newMenu1.setAttribute("hidden", "false");
+        menu.forceUpdateNativeMenuAt("1");
+
+        // Check that "path components" which are out-of-range are not ignored.
+        // There are only two menu items in the root menu (with index 0 and 1),
+        // so index 2 is out of range.
+        is(activateItem(menu, "2|1|0"), "", "#39:" + sna);
+
+        // Check that hiding and then un-hiding the root menu doesn't result in
+        // a cyclic native menu structure.
+        menuNode.setAttribute("collapsed", "true");
+        menuNode.removeAttribute("collapsed");
+        ok(runBaseMenuTests(menu), "base tests #9");
+
+        // Run tests where the menu nodes are not in the document's node tree.
+        runDetachedMenuTests(false);
+        runDetachedMenuTests(true);
+
+        } catch (e) {
+          ok(false, "Caught an exception: " + e);
+        } finally {
+          onTestsFinished();
+        }
+      }
+
+      setTimeout(_delayedOnLoad, 1000);
+    }
+
+  ]]></script>
+</window>
diff --git a/widget/tests/system_font_changes.xhtml b/widget/tests/system_font_changes.xhtml
new file mode 100644
index 0000000000..1cef650015
--- /dev/null
+++ b/widget/tests/system_font_changes.xhtml
@@ -0,0 +1,63 @@
+<?xml version="1.0"?>
+
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+
+<window id="system_font_changes_window"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        width="300"
+        height="300"
+        onload="start();">
+
+<span id="target" style="font:menu">Hello world</span>
+
+<script type="application/javascript"><![CDATA[
+  function is(condition, message) {
+    window.arguments[0].SimpleTest.is(condition, message);
+  }
+  function registerCleanupFunction(func) {
+    window.arguments[0].SimpleTest.registerCleanupFunction(func);
+  }
+
+  async function waitForFrame() {
+    return new Promise(resolve => {
+      requestAnimationFrame(resolve);
+    });
+  }
+
+  let windowUtils = window.windowUtils;
+  async function start() {
+    await waitForFrame();
+
+    const originalSystemFont = windowUtils.systemFont;
+    registerCleanupFunction(() => {
+      windowUtils.systemFont = originalSystemFont;
+    });
+
+    windowUtils.systemFont = 'Sans 11';
+    is(windowUtils.systemFont, 'Sans 11');
+
+    // Wait for two frames for the safety since the notification for system
+    // font changes is asynchronously processed.
+    await waitForFrame();
+    await waitForFrame();
+
+    const target = document.getElementById('target');
+    is(getComputedStyle(target).fontFamily, 'Sans');
+
+    windowUtils.systemFont = 'Serif 11';
+    is(windowUtils.systemFont, 'Serif 11');
+
+    await waitForFrame();
+    await waitForFrame();
+
+    is(getComputedStyle(target).fontFamily, 'Serif');
+
+    window.close();
+    window.arguments[0].SimpleTest.finish();
+  }
+]]></script>
+</window>
diff --git a/widget/tests/taskbar_previews.xhtml b/widget/tests/taskbar_previews.xhtml
new file mode 100644
index 0000000000..b220d5662b
--- /dev/null
+++ b/widget/tests/taskbar_previews.xhtml
@@ -0,0 +1,116 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Taskbar Previews Test"
+  xmlns:html="http://www.w3.org/1999/xhtml"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+  onload="loaded();">
+
+  <title>Previews - yeah!</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+  <script class="testbody" type="application/javascript">
+  <![CDATA[
+    let taskbar = Cc["@mozilla.org/windows-taskbar;1"].getService(Ci.nsIWinTaskbar);
+
+    function IsWin7OrHigher() {
+      try {
+        var ver = parseFloat(Services.sysinfo.getProperty("version"));
+        if (ver >= 6.1)
+          return true;
+      } catch (ex) { }
+      return false;
+    }
+    isnot(taskbar, null, "Taskbar service is defined");
+    is(taskbar.available, IsWin7OrHigher(), "Expected availability of taskbar");
+
+    SimpleTest.waitForExplicitFinish();
+
+    function stdPreviewSuite(p) {
+      p.visible = !p.visible;
+      p.visible = !p.visible;
+      p.visible = true;
+      p.invalidate();
+      p.visible = false;
+    }
+
+    function loaded()
+    {
+      if (!taskbar.available)
+        SimpleTest.finish();
+      let controller = {
+        width: 400,
+        height: 400,
+        thumbnailAspectRatio: 1.0,
+        get wrappedJSObject() { return this; }
+      }
+      // HACK from mconnor:
+      let win = Services.wm.getMostRecentWindow("navigator:browser");
+      let docShell = win.gBrowser.docShell;
+
+      let winPreview = taskbar.getTaskbarWindowPreview(docShell);
+      isnot(winPreview, null, "Window preview is not null");
+      winPreview.controller = controller;
+      let button = winPreview.getButton(0);
+      isnot(button, null, "Could get button at valid index");
+      try {
+        winPreview.getButton(-1);
+        ok(false, "Got button at negative index");
+      } catch (ex) {}
+      try {
+        winPreview.getButton(Ci.nsITaskbarWindowPreview.NUM_TOOLBAR_BUTTONS);
+        ok(false, "Got button at index that is too large");
+      } catch (ex) {}
+      button.image = null;
+      stdPreviewSuite(winPreview);
+      // Let's not perma-hide this window from the taskbar
+      winPreview.visible = true;
+
+      let tabP = taskbar.createTaskbarTabPreview(docShell, controller);
+      isnot(tabP, null, "Tab preview is not null");
+      is(tabP.controller.wrappedJSObject, controller, "Controllers match");
+      is(tabP.icon, null, "Default icon is null (windows default)");
+      tabP.icon = null;
+      tabP.move(null);
+      try {
+        tabP.move(tabP);
+        ok(false, "Moved a preview next to itself!");
+      } catch (ex) {}
+      stdPreviewSuite(tabP);
+
+      let tabP2 = taskbar.createTaskbarTabPreview(docShell, controller);
+      tabP.visible = true;
+      tabP2.visible = true;
+
+      isnot(tabP2, null, "2nd Tab preview is not null");
+      isnot(tabP,tabP2, "Tab previews are different");
+      tabP.active = true;
+      ok(tabP.active && !tabP2.active, "Only one tab is active (part 1)");
+      tabP2.active = true;
+      ok(!tabP.active && tabP2.active, "Only one tab is active (part 2)");
+      tabP.active = true;
+      ok(tabP.active && !tabP2.active, "Only one tab is active (part 3)");
+      tabP.active = false;
+      ok(!tabP.active && !tabP2.active, "Neither tab is active");
+      is(winPreview.active, false, "Window preview is not active");
+      tabP.active = true;
+      winPreview.active = true;
+      ok(winPreview.active && !tabP.active, "Tab preview takes activation from window");
+      tabP.active = true;
+      ok(tabP.active && !winPreview.active, "Tab preview takes activation from window");
+
+      tabP.visible = false;
+      tabP2.visible = false;
+
+      SimpleTest.finish();
+    }
+  ]]>
+  </script>
+
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <p id="display"></p>
+    <div id="content" style="display: none"></div>
+    <pre id="test"></pre>
+  </body>
+
+</window>
diff --git a/widget/tests/test_AltGr_key_events_in_web_content_on_windows.html b/widget/tests/test_AltGr_key_events_in_web_content_on_windows.html
new file mode 100644
index 0000000000..ff89f8fdad
--- /dev/null
+++ b/widget/tests/test_AltGr_key_events_in_web_content_on_windows.html
@@ -0,0 +1,106 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Testing if AltGr keydown and keyup events are fired in web content on Windows</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="/tests/SimpleTest/EventUtils.js"></script>
+  <script src="/tests/SimpleTest/NativeKeyCodes.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css">
+</head>
+<body>
+<div id="display">
+  <input id="input">
+</div>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+</pre>
+
+<script class="testbody" type="application/javascript">
+SimpleTest.waitForExplicitFinish();
+
+function checkEvent(aEvent, aExpectedEvents, aDescription) {
+  if (!aExpectedEvents.length) {
+    ok(false, `${aDescription}: no more expected events ` +
+              `(type: ${aEvent.type}, code: ${aEvent.code}, key: ${aEvent.key}, keyCode: ${aEvent.keyCode}`);
+  }
+  let expectedEvent = aExpectedEvents.shift();
+  for (let property in expectedEvent) {
+    is(aEvent[property], expectedEvent[property], `${aDescription}: ${property}`);
+  }
+}
+
+async function runAltGrKeyTest() {
+  return new Promise(resolve => {
+    let target = document.getElementById("input");
+    target.focus();
+
+    let events = [
+      { type: "keydown", code: "ControlLeft", key: "Control", keyCode: KeyboardEvent.DOM_VK_CONTROL },
+      { type: "keydown", code: "AltRight", key: "AltGraph", keyCode: KeyboardEvent.DOM_VK_ALT },
+      { type: "keyup", code: "ControlLeft", key: "Control", keyCode: KeyboardEvent.DOM_VK_CONTROL },
+      { type: "keyup", code: "AltRight", key: "AltGraph", keyCode: KeyboardEvent.DOM_VK_ALT },
+    ];
+    function handleEvent(aEvent) {
+      checkEvent(aEvent, events, "runAltGrKeyTest");
+      if (aEvent.type === "keyup" && aEvent.code === "AltRight") {
+        is(events.length, 0, "runAltGrKeyTest: all expected events are fired");
+        SimpleTest.executeSoon(() => {
+          target.removeEventListener("keydown", handleEvent);
+          target.removeEventListener("keypress", handleEvent);
+          target.removeEventListener("keyup", handleEvent);
+          resolve();
+        });
+      }
+    }
+    target.addEventListener("keydown", handleEvent);
+    target.addEventListener("keypress", handleEvent);
+    target.addEventListener("keyup", handleEvent);
+
+    synthesizeNativeKey(KEYBOARD_LAYOUT_SPANISH, WIN_VK_RMENU, {},
+                        "", "");
+  });
+}
+
+async function runEmulatingAltGrKeyTest() {
+  return new Promise(resolve => {
+    let target = document.getElementById("input");
+    target.focus();
+
+    let events = [
+      { type: "keydown", code: "ControlLeft", key: "Control", keyCode: KeyboardEvent.DOM_VK_CONTROL },
+      { type: "keydown", code: "AltLeft", key: "Alt", keyCode: KeyboardEvent.DOM_VK_ALT },
+      { type: "keyup", code: "AltLeft", key: "Alt", keyCode: KeyboardEvent.DOM_VK_ALT },
+      { type: "keyup", code: "ControlLeft", key: "Control", keyCode: KeyboardEvent.DOM_VK_CONTROL },
+    ];
+    function handleEvent(aEvent) {
+      checkEvent(aEvent, events, "runEmulatingAltGrKeyTest");
+      if (aEvent.type === "keyup" && aEvent.code === "ControlLeft") {
+        is(events.length, 0, "runAltGrKeyTest: all expected events are fired");
+        SimpleTest.executeSoon(() => {
+          target.removeEventListener("keydown", handleEvent);
+          target.removeEventListener("keypress", handleEvent);
+          target.removeEventListener("keyup", handleEvent);
+          resolve();
+        });
+      }
+    }
+    target.addEventListener("keydown", handleEvent);
+    target.addEventListener("keypress", handleEvent);
+    target.addEventListener("keyup", handleEvent);
+
+    synthesizeNativeKey(KEYBOARD_LAYOUT_SPANISH, WIN_VK_LMENU, { ctrlKey: true },
+                        "", "");
+  });
+}
+
+async function runTests() {
+  await runAltGrKeyTest();
+  await runEmulatingAltGrKeyTest();
+  SimpleTest.finish();
+}
+
+SimpleTest.waitForFocus(runTests);
+</script>
+</body>
+</html>
\ No newline at end of file
diff --git a/widget/tests/test_actionhint.html b/widget/tests/test_actionhint.html
new file mode 100644
index 0000000000..6ab2cf40de
--- /dev/null
+++ b/widget/tests/test_actionhint.html
@@ -0,0 +1,114 @@
+<!DOCTYPE html>
+<html>
+<head>
+<title>Tests for action hint that is used by software keyboard</title>
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<script src="/tests/SimpleTest/SpecialPowers.js"></script>
+<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+<div>
+<form><input type="text" id="a1"><input type="text" id="a2"><input type="submit"></form>
+<form><input type="search" id="b1"><input type="submit"></form>
+<form><input type="text" id="c1"></form>
+<form><input type="text" id="d1"><textarea></textarea><input type="submit"></form>
+<form><input type="text" id="e1"><input type="number"><input type="submit"></form>
+<form><input type="text" id="f1"><input type="date"><input type="submit"></form>
+<form><input type="text" id="g1"><input type="radio"><input type="submit"></form>
+<form><input type="text" id="h1"><input type="text" readonly><input type="submit"></form>
+<form><input type="text" id="i1"><input type="text" disabled><input type="submit"></form>
+<input type="text" id="j1"><input type="text"><input type="button">
+<form><input type="text" id="k1"><a href="#foo">foo</a><input type="text"><input type="submit"></form>
+<form>
+  <input id="l1" enterkeyhint="enter">
+  <input id="l2" enterkeyhint="DONE">
+  <input id="l3" enterkeyhint="go">
+  <input id="l4" enterkeyhint="Next">
+  <input id="l5" enterkeyhint="Previous">
+  <input id="l6" enterkeyhint="search">
+  <textarea id="l7" enterkeyhint="send"></textarea>
+  <input id="l8" type="number" enterkeyhint="previous">
+  <input id="l9" type="date" enterkeyhint="done">
+  <input id="l10" type="time" enterkeyhint="done">
+  <input id="l11" enterkeyhint="NONE">
+</form>
+</div>
+<pre id="test">
+<script class="testbody" type="application/javascript">
+add_task(async function setup() {
+  await new Promise(r => SimpleTest.waitForFocus(r));
+});
+
+add_task(async function basic() {
+  const tests = [
+    { id: "a1", hint: "maybenext", desc: "next element is type=text" },
+    { id: "a2", hint: "go", desc: "next element is type=submit" },
+    { id: "b1", hint: "search", desc: "current is type=search" },
+    { id: "c1", hint: "go", desc: "only this element" },
+    { id: "d1", hint: "maybenext", desc: "next element is textarea" },
+    { id: "e1", hint: "maybenext", desc: "next element is type=number" },
+    { id: "h1", hint: "go", desc: "next element is readonly" },
+    // XXX Feel free to change this result if you get some bugs reports
+    { id: "i1", hint: "go", desc: "next element is disabled" },
+    { id: "j1", hint: "", desc: "no form element" },
+    { id: "l1", hint: "enter", desc: "enterkeyhint=enter" },
+    { id: "l2", hint: "done", desc: "enterkeyhint=DONE" },
+    { id: "l3", hint: "go", desc: "enterkeyhint=go" },
+    { id: "l4", hint: "next", desc: "enterkeyhint=Next" },
+    { id: "l5", hint: "previous", desc: "enterkeyhint=Previous" },
+    { id: "l6", hint: "search", desc: "enterkeyhint=search" },
+    { id: "l7", hint: "send", desc: "enterkeyhint=send" },
+    { id: "l8", hint: "previous", desc: "type=number enterkeyhint=previous" },
+    // type=date is readonly content
+    { id: "l9", hint: "", desc: "type=date enterkeyhint=done" },
+    // type=time is readonly content
+    { id: "l10", hint: "", desc: "type=time enterkeyhint=done" },
+    // Since enterkeyhint is invalid, we infer action hint. So feel free to change this.
+    { id: "l11", hint: "go", desc: "enterkeyhint is invalid" },
+  ];
+
+  const todo_tests = [
+    { id: "f1", hint: "maybenext", desc: "next element is type=date" },
+    { id: "k1", hint: "", desc: "next is anchor link" },
+  ];
+
+
+  for (let test of tests) {
+    document.getElementById(test.id).focus();
+    is(SpecialPowers.DOMWindowUtils.focusedActionHint, test.hint, test.desc);
+  }
+
+  for (let test of todo_tests) {
+    document.getElementById(test.id).focus();
+    todo_is(SpecialPowers.DOMWindowUtils.focusedActionHint, test.hint, test.desc);
+  }
+});
+
+add_task(async function dynamicChange() {
+  let element = document.getElementById("l1");
+  element.focus();
+  is(SpecialPowers.DOMWindowUtils.focusedActionHint, "enter",
+     "Initial enterKeyHint");
+
+  element.setAttribute("enterkeyhint", "next");
+  is(SpecialPowers.DOMWindowUtils.focusedActionHint, "next",
+     "enterKeyHint in InputContext has to sync with enterkeyhint attribute");
+
+  element.enterKeyHint = "search";
+  is(SpecialPowers.DOMWindowUtils.focusedActionHint, "search",
+     "enterKeyHint in InputContext has to sync with enterKeyHint setter");
+
+  document.getElementById("l2").setAttribute("enterkeyhint", "send");
+  is(SpecialPowers.DOMWindowUtils.focusedActionHint, "search",
+     "enterKeyHint in InputContext keeps focused enterKeyHint value");
+
+  // Storing the original value may be safer.
+  element.enterkeyhint = "enter";
+  document.getElementById("l2").enterKeyHint = "done";
+});
+</script>
+</pre>
+</body>
+</html>
diff --git a/widget/tests/test_alwaysontop_focus.xhtml b/widget/tests/test_alwaysontop_focus.xhtml
new file mode 100644
index 0000000000..b9cc3ee33c
--- /dev/null
+++ b/widget/tests/test_alwaysontop_focus.xhtml
@@ -0,0 +1,38 @@
+<!DOCTYPE HTML>
+<html xmlns="http://www.w3.org/1999/xhtml">
+<head>
+  <meta charset="utf-8" />
+  <title>Test that alwaysontop windows do not pull focus when opened.</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <script><![CDATA[
+    add_task(async function testAlwaysOnTop() {
+      let topWin = window.docShell.rootTreeItem.domWindow;
+      await SimpleTest.promiseFocus(topWin);
+      is(Services.focus.activeWindow, topWin, "Top level window is focused");
+
+      let newWin = Services.ww.openWindow(
+        null,
+        "about:blank",
+        null,
+        "chrome,alwaysontop,width=300,height=300",
+        null
+      );
+      await new Promise(resolve => {
+        newWin.addEventListener("load", resolve, { once: true });
+      });
+
+      // Wait one tick of the event loop to give the window a chance to focus.
+      await new Promise(resolve => { SimpleTest.executeSoon(resolve); });
+
+      is(Services.focus.activeWindow, topWin, "Top level window is still focused");
+      newWin.close();
+    });
+  ]]></script>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+<pre id="test"></pre>
+</body>
+</html>
diff --git a/widget/tests/test_assign_event_data.html b/widget/tests/test_assign_event_data.html
new file mode 100644
index 0000000000..1da9bb535f
--- /dev/null
+++ b/widget/tests/test_assign_event_data.html
@@ -0,0 +1,708 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Testing ns*Event::Assign*EventData()</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="/tests/SimpleTest/EventUtils.js"></script>
+  <script src="/tests/SimpleTest/NativeKeyCodes.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css">
+  <style>
+    #a {
+      background-color: transparent;
+      transition: background-color 0.1s linear;
+    }
+    #a:focus {
+      background-color: red;
+    }
+    .slidin {
+      border: green 1px solid;
+      width: 10px;
+      height: 10px;
+      animation-name: slidein;
+      animation-duration: 1s;
+    }
+    @keyframes slidein {
+      from {
+        margin-left: 100%;
+      }
+      to {
+        margin-left: 0;
+      }
+    }
+    #pointer-target {
+      border: 1px dashed red;
+      background: yellow;
+      margin: 0px 10px;
+      padding: 0px 10px;
+    }
+    #scrollable-div {
+      background: green;
+      overflow: auto;
+      width: 30px;
+      height: 30px;
+    }
+    #scrolled-div {
+      background: magenta;
+      width: 10px;
+      height: 10px;
+    }
+    #form {
+      background: silver;
+      padding: 0px 10px;
+    }
+    #animated-div {
+      background: cyan;
+      padding: 0px 10px;
+    }
+  </style>
+</head>
+<body>
+<div id="display">
+  <input id="input-text">
+  <button id="button">button</button>
+  <a id="a" href="about:blank">hyper link</a>
+  <span id="pointer-target">span</span>
+  <div id="scrollable-div"><div id="scrolled-div"></div></div>
+  <form id="form">form</form>
+  <div id="animated-div">&nbsp;</div>
+</div>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+</pre>
+
+<script class="testbody" type="application/javascript">
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.expectAssertions(0, 34);
+
+const kIsMac = (navigator.platform.indexOf("Mac") == 0);
+const kIsWin = (navigator.platform.indexOf("Win") == 0);
+
+var gDescription = "";
+var gEvent = null;
+var gCopiedEvent = [];
+var gCallback = null;
+var gCallPreventDefault = false;
+
+function onEvent(aEvent) {
+  if (gCallPreventDefault) {
+    aEvent.preventDefault();
+  }
+  ok(gEvent === null, gDescription + `: We should receive only one event to check per test: already got: ${gEvent ? gEvent.type : "null"}, got: ${aEvent.type}`);
+  gEvent = aEvent;
+  for (var attr in aEvent) {
+    if (!attr.match(/^[A-Z0-9_]+$/) && // ignore const attributes
+        attr != "multipleActionsPrevented" && // multipleActionsPrevented isn't defined in any DOM event specs.
+        typeof(aEvent[attr]) != "function") {
+      gCopiedEvent.push({ name: attr, value: aEvent[attr]});
+    }
+  }
+  setTimeout(gCallback, 0);
+}
+
+function observeKeyUpOnContent(aKeyCode, aCallback) {
+  document.addEventListener("keyup", function keyUp(ev) {
+    if (ev.keyCode == aKeyCode) {
+      document.removeEventListener("keyup", keyUp);
+      SimpleTest.executeSoon(aCallback);
+    }
+  });
+}
+
+const kTests = [
+  { description: "InternalScrollPortEvent (overflow, vertical)",
+    targetID: "scrollable-div", eventType: "overflow",
+    dispatchEvent() {
+      document.getElementById("scrolled-div").style.height = "500px";
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalScrollPortEvent (overflow, horizontal)",
+    targetID: "scrollable-div", eventType: "overflow",
+    dispatchEvent() {
+      document.getElementById("scrolled-div").style.width = "500px";
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalScrollAreaEvent (MozScrolledAreaChanged, spreading)",
+    target() { return document; }, eventType: "MozScrolledAreaChanged",
+    dispatchEvent() {
+      document.getElementById("scrollable-div").style.width = "50000px";
+      document.getElementById("scrollable-div").style.height = "50000px";
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalScrollAreaEvent (MozScrolledAreaChanged, shrinking)",
+    target() { return document; }, eventType: "MozScrolledAreaChanged",
+    dispatchEvent() {
+      document.getElementById("scrollable-div").style.width = "30px";
+      document.getElementById("scrollable-div").style.height = "30px";
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "WidgetKeyboardEvent (keydown of 'a' key without modifiers)",
+    targetID: "input-text", eventType: "keydown",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      document.getElementById(this.targetID).focus();
+      synthesizeNativeKey(KEYBOARD_LAYOUT_EN_US, kIsWin ? WIN_VK_A : MAC_VK_ANSI_A,
+                          {}, "a", "a");
+      observeKeyUpOnContent(KeyboardEvent.DOM_VK_A, runNextTest);
+      return true;
+    },
+    canRun() {
+      return (kIsMac || kIsWin);
+    },
+    todoMismatch: [],
+  },
+  { description: "WidgetKeyboardEvent (keyup of 'a' key without modifiers)",
+    targetID: "input-text", eventType: "keydown",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      document.getElementById(this.targetID).focus();
+      synthesizeNativeKey(KEYBOARD_LAYOUT_EN_US, kIsWin ? WIN_VK_A : MAC_VK_ANSI_A,
+                          {}, "a", "a");
+      observeKeyUpOnContent(KeyboardEvent.DOM_VK_A, runNextTest);
+      return true;
+    },
+    canRun() {
+      return (kIsMac || kIsWin);
+    },
+    todoMismatch: [],
+  },
+  { description: "WidgetKeyboardEvent (keypress of 'b' key with Shift)",
+    targetID: "input-text", eventType: "keypress",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      document.getElementById(this.targetID).focus();
+      synthesizeNativeKey(KEYBOARD_LAYOUT_EN_US, kIsWin ? WIN_VK_B : MAC_VK_ANSI_B,
+                          { shiftKey: true }, "B", "B");
+
+      // On Windows, synthesizeNativeKey will also fire keyup for shiftKey.
+      // We have to wait for it to prevent the key event break the next test case.
+      let waitKeyCode = _EU_isWin(window) ? KeyboardEvent.DOM_VK_SHIFT :
+                                            KeyboardEvent.DOM_VK_B;
+      observeKeyUpOnContent(waitKeyCode, runNextTest);
+      return true;
+    },
+    canRun() {
+      return (kIsMac || kIsWin);
+    },
+    todoMismatch: [],
+  },
+  { description: "WidgetKeyboardEvent (keyup during composition)",
+    targetID: "input-text", eventType: "keyup",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      document.getElementById(this.targetID).focus();
+      synthesizeCompositionChange({ "composition":
+        { "string": "\u306D",
+          "clauses":
+          [
+            { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE },
+          ],
+        },
+        "caret": { "start": 1, "length": 0 },
+        "key": { key: "a" },
+      });
+      synthesizeComposition({ type: "compositioncommitasis", key: {} });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetKeyboardEvent (keydown during composition)",
+    targetID: "input-text", eventType: "keydown",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      document.getElementById(this.targetID).focus();
+      synthesizeCompositionChange({ "composition":
+        { "string": "\u306D",
+          "clauses":
+          [
+            { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE },
+          ],
+        },
+        "caret": { "start": 1, "length": 0 },
+        "key": {},
+      });
+      synthesizeComposition({ type: "compositioncommitasis",
+        key: { key: "KEY_Enter" } });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetMouseEvent (mousedown of left button without modifier)",
+    targetID: "button", eventType: "mousedown",
+    dispatchEvent() {
+      synthesizeMouseAtCenter(document.getElementById(this.targetID),
+                              { button: 0 });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "WidgetMouseEvent (click of middle button with Shift)",
+    targetID: "button", eventType: "auxclick",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      synthesizeMouseAtCenter(document.getElementById(this.targetID),
+                              { button: 1, shiftKey: true, pressure: 0.5 });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "WidgetMouseEvent (mouseup of right button with Alt)",
+    targetID: "button", eventType: "mouseup",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      synthesizeMouseAtCenter(document.getElementById(this.targetID),
+                              { button: 2, altKey: true });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "WidgetDragEvent",
+    targetID: "input-text", eventType: "dragstart",
+    dispatchEvent() {
+
+    },
+    canRun() {
+      todo(false, "WidgetDragEvent isn't tested");
+      return false;
+    },
+    todoMismatch: [],
+  },
+  { description: "WidgetCompositionEvent (compositionupdate)",
+    targetID: "input-text", eventType: "compositionupdate",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      document.getElementById(this.targetID).focus();
+      synthesizeComposition({ type: "compositioncommit", data: "\u30E9\u30FC\u30E1\u30F3", key: { key: "KEY_Enter" } });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "InternalEditorInputEvent (input at key input)",
+    targetID: "input-text", eventType: "input",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      document.getElementById(this.targetID).focus();
+      synthesizeNativeKey(KEYBOARD_LAYOUT_EN_US, kIsWin ? WIN_VK_B : MAC_VK_ANSI_B,
+                          { shiftKey: true }, "B", "B");
+      observeKeyUpOnContent(KeyboardEvent.DOM_VK_B, runNextTest);
+      return true;
+    },
+    canRun() {
+      return (kIsMac || kIsWin);
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalEditorInputEvent (input at composing)",
+    targetID: "input-text", eventType: "input",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      document.getElementById(this.targetID).focus();
+      synthesizeCompositionChange({ "composition":
+        { "string": "\u30E9\u30FC\u30E1\u30F3",
+          "clauses":
+          [
+            { "length": 4, "attr": COMPOSITION_ATTR_RAW_CLAUSE },
+          ],
+        },
+        "caret": { "start": 4, "length": 0 },
+        "key": { key: "y" },
+      });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "InternalEditorInputEvent (input at committing)",
+    targetID: "input-text", eventType: "input",
+    dispatchEvent() {
+      synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetMouseScrollEvent (DOMMouseScroll, vertical)",
+    targetID: "input-text", eventType: "DOMMouseScroll",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      synthesizeWheel(document.getElementById(this.targetID), 3, 4,
+                      { deltaY: 30, lineOrPageDeltaY: 2 });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetMouseScrollEvent (DOMMouseScroll, horizontal)",
+    targetID: "input-text", eventType: "DOMMouseScroll",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      synthesizeWheel(document.getElementById(this.targetID), 4, 5,
+                      { deltaX: 30, lineOrPageDeltaX: 2, shiftKey: true });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetMouseScrollEvent (MozMousePixelScroll, vertical)",
+    targetID: "input-text", eventType: "MozMousePixelScroll",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      synthesizeWheel(document.getElementById(this.targetID), 3, 4,
+                      { deltaY: 20, lineOrPageDeltaY: 1, altKey: true });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetMouseScrollEvent (MozMousePixelScroll, horizontal)",
+    targetID: "input-text", eventType: "MozMousePixelScroll",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      synthesizeWheel(document.getElementById(this.targetID), 4, 5,
+                      { deltaX: 20, lineOrPageDeltaX: 1, ctrlKey: true });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetWheelEvent (wheel, vertical)",
+    targetID: "input-text", eventType: "wheel",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      synthesizeWheel(document.getElementById(this.targetID), 3, 4,
+                      { deltaY: 20, lineOrPageDeltaY: 1, altKey: true });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetWheelEvent (wheel, horizontal)",
+    targetID: "input-text", eventType: "wheel",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      synthesizeWheel(document.getElementById(this.targetID), 4, 5,
+                      { deltaX: 20, lineOrPageDeltaX: 1, ctrlKey: true });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetWheelEvent (wheel, both)",
+    targetID: "input-text", eventType: "wheel",
+    dispatchEvent() {
+      document.getElementById(this.targetID).value = "";
+      synthesizeWheel(document.getElementById(this.targetID), 4, 5,
+                      { deltaX: 20, deltaY: 10,
+                        lineOrPageDeltaX: 1, lineOrPageDeltaY: 1 });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetTouchEvent (touchstart)",
+    target() { return document; }, eventType: "touchstart",
+    dispatchEvent() {
+      synthesizeTouchAtPoint(1, 2, { id: 10, rx: 4, ry: 3, angle: 0, force: 1, shiftKey: true});
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetTouchEvent (touchend)",
+    target() { return document; }, eventType: "touchend",
+    dispatchEvent() {
+      synthesizeTouchAtPoint(4, 6, { id: 5, rx: 1, ry: 2, angle: 0.5, force: 0.8, ctrlKey: true});
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "InternalFormEvent (reset)",
+    targetID: "form", eventType: "reset",
+    dispatchEvent() {
+      document.getElementById("form").reset();
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "WidgetCommandEvent",
+    targetID: "input-text", eventType: "",
+    dispatchEvent() {
+
+    },
+    canRun() {
+      todo(false, "WidgetCommandEvent isn't tested");
+      return false;
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalClipboardEvent (copy)",
+    targetID: "input-text", eventType: "copy",
+    dispatchEvent() {
+      document.getElementById("input-text").value = "go to clipboard!";
+      document.getElementById("input-text").focus();
+      document.getElementById("input-text").select();
+      synthesizeKey("c", { accelKey: true });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [ ],
+  },
+  { description: "InternalUIEvent (DOMActivate)",
+    targetID: "button", eventType: "DOMActivate",
+    dispatchEvent() {
+      synthesizeMouseAtCenter(document.getElementById(this.targetID),
+                              { button: 0, shiftKey: true });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalFocusEvent (focus)",
+    targetID: "input-text", eventType: "focus",
+    dispatchEvent() {
+      document.getElementById(this.targetID).focus();
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalFocusEvent (blur)",
+    targetID: "input-text", eventType: "blur",
+    dispatchEvent() {
+      document.getElementById(this.targetID).blur();
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "WidgetSimpleGestureEvent",
+    targetID: "", eventType: "",
+    dispatchEvent() {
+
+    },
+    canRun() {
+      // Simple gesture event may be handled before it comes content.
+      // So, we cannot test it in this test.
+      todo(false, "WidgetSimpleGestureEvent isn't tested");
+      return false;
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalTransitionEvent (transitionend)",
+    targetID: "a", eventType: "transitionend",
+    dispatchEvent() {
+      document.getElementById(this.targetID).focus();
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalAnimationEvent (animationend)",
+    targetID: "animated-div", eventType: "animationend",
+    dispatchEvent() {
+      document.getElementById(this.targetID).className = "slidin";
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalMutationEvent (DOMAttrModified)",
+    targetID: "animated-div", eventType: "DOMAttrModified",
+    dispatchEvent() {
+      document.getElementById(this.targetID).setAttribute("x-data", "foo");
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalMutationEvent (DOMNodeInserted)",
+    targetID: "animated-div", eventType: "DOMNodeInserted",
+    dispatchEvent() {
+      var div = document.createElement("div");
+      div.id = "inserted-div";
+      document.getElementById("animated-div").appendChild(div);
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "InternalMutationEvent (DOMNodeRemoved)",
+    targetID: "animated-div", eventType: "DOMNodeRemoved",
+    dispatchEvent() {
+      document.getElementById("animated-div").removeChild(document.getElementById("inserted-div"));
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "PointerEvent (pointerdown)",
+    targetID: "pointer-target", eventType: "mousedown",
+    dispatchEvent() {
+      var elem = document.getElementById(this.targetID);
+      var rect = elem.getBoundingClientRect();
+      synthesizeMouse(elem, rect.width / 2, rect.height / 2,
+                      { type: this.eventType, button: 1, clickCount: 1, inputSource: 2, pressure: 0.25, isPrimary: true });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+  { description: "PointerEvent (pointerup)",
+    targetID: "pointer-target", eventType: "mouseup",
+    dispatchEvent() {
+      var elem = document.getElementById(this.targetID);
+      var rect = elem.getBoundingClientRect();
+      synthesizeMouse(elem, rect.width / 2, rect.height / 2,
+                      { type: this.eventType, button: -1, ctrlKey: true, shiftKey: true, altKey: true, isSynthesized: false });
+    },
+    canRun() {
+      return true;
+    },
+    todoMismatch: [],
+  },
+];
+
+function doTest(aTest) {
+  if (!aTest.canRun()) {
+    SimpleTest.executeSoon(runNextTest);
+    return;
+  }
+  gEvent = null;
+  gCopiedEvent = [];
+  gDescription = aTest.description + " (gCallPreventDefault=" + gCallPreventDefault + ")";
+  var target = aTest.target ? aTest.target() : document.getElementById(aTest.targetID);
+  target.addEventListener(aTest.eventType, onEvent, true);
+  gCallback = function() {
+    target.removeEventListener(aTest.eventType, onEvent, true);
+    ok(gEvent !== null, gDescription + ": failed to get duplicated event");
+    ok(!!gCopiedEvent.length, gDescription + ": count of attribute of the event must be larger than 0");
+    for (var i = 0; i < gCopiedEvent.length; ++i) {
+      var name = gCopiedEvent[i].name;
+      if (name == "rangeOffset") {
+        todo(false, gDescription + ": " + name + " attribute value is never reset (" + gEvent[name] + ")");
+      } else if (name == "eventPhase") {
+        is(gEvent[name], 0, gDescription + ": mismatch with fixed value (" + name + ")");
+      } else if (name == "rangeParent" || name == "currentTarget") {
+        is(gEvent[name], null, gDescription + ": mismatch with fixed value (" + name + ")");
+      } else if (aTest.todoMismatch.includes(name)) {
+        todo_is(gEvent[name], gCopiedEvent[i].value, gDescription + ": mismatch (" + name + ")");
+      } else if (name == "offsetX" || name == "offsetY") {
+        // do nothing; these are defined to return different values during event dispatch
+        // vs not during event dispatch
+      } else {
+        is(gEvent[name], gCopiedEvent[i].value, gDescription + ": mismatch (" + name + ")");
+      }
+    }
+    if (!testWillCallRunNextTest) {
+      runNextTest();
+    }
+  };
+  var testWillCallRunNextTest = aTest.dispatchEvent();
+}
+
+var gIndex = -1;
+function runNextTest() {
+  if (++gIndex == kTests.length) {
+    if (gCallPreventDefault) {
+      finish();
+      return;
+    }
+    // Test with a call of preventDefault() of the events.
+    gCallPreventDefault = true;
+    gIndex = -1;
+    // Restoring the initial state of all elements.
+    document.getElementById("scrollable-div").style.height = "30px";
+    document.getElementById("scrollable-div").style.width = "30px";
+    document.getElementById("scrolled-div").style.height = "10px";
+    document.getElementById("scrolled-div").style.width = "10px";
+    document.getElementById("input-text").value = "";
+    document.getElementById("animated-div").className = "";
+    document.getElementById("animated-div").removeAttribute("x-data");
+    if (document.activeElement) {
+      document.activeElement.blur();
+    }
+    window.requestAnimationFrame(function() {
+      setTimeout(runNextTest, 0);
+    });
+    return;
+  }
+  doTest(kTests[gIndex]);
+}
+
+function init() {
+  SpecialPowers.pushPrefEnv({"set": [["middlemouse.contentLoadURL", false],
+                                    ["middlemouse.paste", false],
+                                    ["general.autoScroll", false],
+                                    ["mousewheel.default.action", 0],
+                                    ["mousewheel.default.action.override_x", -1],
+                                    ["mousewheel.with_shift.action", 0],
+                                    ["mousewheel.with_shift.action.override_x", -1],
+                                    ["mousewheel.with_control.action", 0],
+                                    ["mousewheel.with_control.action.override_x", -1],
+                                    ["mousewheel.with_alt.action", 0],
+                                    ["mousewheel.with_alt.action.override_x", -1],
+                                    ["mousewheel.with_meta.action", 0],
+                                    ["mousewheel.with_meta.action.override_x", -1]]}, runNextTest);
+}
+
+function finish() {
+  SimpleTest.finish();
+}
+
+SimpleTest.waitForFocus(init);
+
+</script>
+</body>
diff --git a/widget/tests/test_autocapitalize.html b/widget/tests/test_autocapitalize.html
new file mode 100644
index 0000000000..de628d1190
--- /dev/null
+++ b/widget/tests/test_autocapitalize.html
@@ -0,0 +1,62 @@
+<!DOCTYPE html>
+<html>
+<head>
+<title>Tests for autocapitalize that is used by software keyboard</title>
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<script src="/tests/SimpleTest/SpecialPowers.js"></script>
+<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+
+<div>
+<input type="text" id="a1"><br>
+<input type="text" id="a2" autocapitalize="characters"><br>
+<input type="text" id="a3" autocapitalize="sentences"><br>
+<input type="text" id="a4" autocapitalize="words"><br>
+<input type="text" id="a5" autocapitalize="off"><br>
+<input type="text" id="a6" autocapitalize="on"><br>
+<input type="url" id="a7" autocapitalize="on"><br>
+<input type="email" id="a8" autocapitalize="on"><br>
+<input type="password" id="a9" autocapitalize="on"><br>
+<textarea id="b1" autocapitalize="characters"></textarea><br>
+<div contenteditable id="c1" autocapitalize="sentences"></div><br>
+<form><input type="text" id="d1" autocapitalize="words"></form><br>
+<form autocapitalize="on"><input type="text" id="d2"></form><br>
+<form autocapitalize="off"><input type="text" id="d3" autocapitalize="on"></form><br>
+</div>
+
+<pre id="test">
+<script class="testbody" type="application/javascript">
+SimpleTest.waitForExplicitFinish();
+
+SimpleTest.waitForFocus(async () => {
+  const tests = [
+    { id: "a1", autocapitalize: "", desc: "input without autocapitalize" },
+    { id: "a2", autocapitalize: "characters", desc: "input with autocapitalize=characters" },
+    { id: "a3", autocapitalize: "sentences", desc: "input with autocapitalize=sentences" },
+    { id: "a4", autocapitalize: "words", desc: "input with autocapitalize=words" },
+    { id: "a5", autocapitalize: "none", desc: "input with autocapitalize=off" },
+    { id: "a6", autocapitalize: "sentences", desc: "input with autocapitalize=on" },
+    { id: "a7", autocapitalize: "", desc: "input with type=url and autocapitalize=on" },
+    { id: "a8", autocapitalize: "", desc: "input with type=email and autocapitalize=on" },
+    { id: "a9", autocapitalize: "", desc: "input with type=password and autocapitalize=on" },
+    { id: "b1", autocapitalize: "characters", desc: "textarea with autocapitalize=characters" },
+    { id: "c1", autocapitalize: "sentences", desc: "contenteditable with autocapitalize=sentences" },
+    { id: "d1", autocapitalize: "words", desc: "input with autocapitalize=words in form" },
+    { id: "d2", autocapitalize: "sentences", desc: "input in form with autocapitalize=on" },
+    { id: "d3", autocapitalize: "sentences", desc: "input with autocapitalize=on in form" },
+  ];
+
+  for (let test of tests) {
+    document.getElementById(test.id).focus();
+    is(SpecialPowers.DOMWindowUtils.focusedAutocapitalize, test.autocapitalize, test.desc);
+  }
+
+  SimpleTest.finish();
+});
+</script>
+</pre>
+</body>
+</html>
diff --git a/widget/tests/test_bug1123480.xhtml b/widget/tests/test_bug1123480.xhtml
new file mode 100644
index 0000000000..18a40202fd
--- /dev/null
+++ b/widget/tests/test_bug1123480.xhtml
@@ -0,0 +1,155 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1123480
+-->
+<window title="Mozilla Bug 1123480"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        onload="RunTest();">
+  <title>nsTransferable PBM Overflow Selection Test</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <script type="application/javascript">
+  <![CDATA[
+  // Create over 1 MB of sample garbage text. JavaScript strings are represented by
+  // UTF16 strings, so the size is twice as much as the actual string length.
+  // This value is chosen such that the size of the memory for the string exceeds
+  // the kLargeDatasetSize threshold in nsTransferable.h.
+  // It is also not a round number to reduce the odds of having an accidental
+  // collisions with another file (since the test below looks at the file size
+  // to identify the file).
+  var Ipsum = "0123456789".repeat(1234321);
+  var IpsumByteLength = Ipsum.length * 2;
+  var SHORT_STRING_NO_CACHE = "short string that will never be cached to the disk";
+
+  function isWindows() {
+    const {AppConstants} = ChromeUtils.importESModule(
+      "resource://gre/modules/AppConstants.sys.mjs"
+    );
+    return AppConstants.platform === 'win';
+  }
+
+  // Get a list of open file descriptors that refer to a file with the same size as
+  // the expected data (and assume that any mutations in file descriptor counts
+  // are caused by our test).
+  function getClipboardCacheFDCount() {
+    var dir = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
+    if (isWindows()) {
+      // On Windows, nsAnonymousTemporaryFile does not immediately delete the file.
+      // Instead, the Windows-specific FILE_FLAG_DELETE_ON_CLOSE flag is used,
+      // which means that the file is deleted when the last handle is closed.
+      // Apparently, this flag is unreliable (e.g. when the application crashes),
+      // so nsAnonymousTemporaryFile stores the temporary files in a subdirectory,
+      // which is cleaned up some time after start-up.
+
+      // This is just a test, and during the test we deterministically close the
+      // handles, so if FILE_FLAG_DELETE_ON_CLOSE does the thing it promises, the
+      // file is actually removed when the handle is closed.
+
+      // Path from nsAnonymousTemporaryFile.cpp, GetTempDir.
+      dir.initWithPath(PathUtils.join(PathUtils.tempDir, "mozilla-temp-files"));
+    } else {
+      dir.initWithPath("/dev/fd");
+    }
+    var count = 0;
+    for (var de = dir.directoryEntries; de.hasMoreElements(); ) {
+      var fdFile = de.nextFile;
+      var fileSize;
+      try {
+        fileSize = fdFile.fileSize;
+      } catch (e) {
+        // This can happen on macOS.
+        continue;
+      }
+      if (fileSize === IpsumByteLength) {
+        // Assume that the file was created by us if the size matches.
+        ++count;
+      }
+    }
+    return count;
+  }
+
+  async function RunTest() {
+    SimpleTest.waitForExplicitFinish();
+    const gClipboardHelper = Cc["@mozilla.org/widget/clipboardhelper;1"].getService(Ci.nsIClipboardHelper);
+
+    // Sanitize environment
+    gClipboardHelper.copyString(SHORT_STRING_NO_CACHE);
+    await new Promise(resolve => setTimeout(resolve, 0));
+
+    var initialFdCount = getClipboardCacheFDCount();
+
+    // Overflow a nsTransferable region by using the clipboard helper
+    gClipboardHelper.copyString(Ipsum);
+
+    // gClipboardHelper.copyString also puts the data on the selection
+    // clipboard if the platform supports it.
+    var expectedFdDelta = Services.clipboard.isClipboardTypeSupported(Services.clipboard.kSelectionClipboard) ? 2 : 1;
+    // Undefined private browsing mode should cache to disk
+    is(getClipboardCacheFDCount(), initialFdCount + expectedFdDelta, "should cache to disk when PBM is undefined");
+
+    // Sanitize environment again.
+    gClipboardHelper.copyString(SHORT_STRING_NO_CACHE);
+    await new Promise(resolve => setTimeout(resolve, 0));
+
+    is(getClipboardCacheFDCount(), initialFdCount, "should have cleared the clipboard data");
+
+    // Repeat procedure of plain text selection with private browsing
+    // disabled and enabled
+    const {PrivateBrowsingUtils} = ChromeUtils.importESModule(
+      "resource://gre/modules/PrivateBrowsingUtils.sys.mjs"
+    );
+    for (let private of [false, true]) {
+      var win = window.browsingContext.topChromeWindow.open("about:blank", "_blank", "chrome, width=500, height=200" + (private ? ", private" : ""));
+      ok(win, private ? "should open private window" : "should open non-private window");
+      is(PrivateBrowsingUtils.isContentWindowPrivate(win), private, "used correct window context");
+
+      // Select plaintext in private/non-private channel
+      const nsTransferable = Components.Constructor("@mozilla.org/widget/transferable;1", "nsITransferable");
+      const nsSupportsString = Components.Constructor("@mozilla.org/supports-string;1", "nsISupportsString");
+      var Loadctx = PrivateBrowsingUtils.privacyContextFromWindow(win);
+      var Transfer = nsTransferable();
+      var Suppstr = nsSupportsString();
+      Suppstr.data = Ipsum;
+      Transfer.init(Loadctx);
+      Transfer.addDataFlavor("text/plain");
+      Transfer.setTransferData("text/plain", Suppstr);
+
+      // Enabled private browsing mode should not cache any selection to disk; disabled should
+      if (private) {
+        is(getClipboardCacheFDCount(), initialFdCount, "did not violate private browsing mode");
+      } else {
+        is(getClipboardCacheFDCount(), initialFdCount + 1, "should save memory by caching non-private clipboard data to disk");
+      }
+
+      // Share the transferable with the system.
+      Services.clipboard.setData(Transfer, null, Services.clipboard.kGlobalClipboard);
+      if (private) {
+        is(getClipboardCacheFDCount(), initialFdCount, "did not violate private browsing mode");
+      } else {
+        is(getClipboardCacheFDCount(), initialFdCount + 1, "should save memory by caching non-private clipboard data to disk");
+      }
+
+      // Sanitize the environment.
+      Suppstr = nsSupportsString();
+      Suppstr.data = SHORT_STRING_NO_CACHE;
+      Transfer.setTransferData("text/plain", Suppstr);
+      await new Promise(resolve => setTimeout(resolve, 0));
+      is(getClipboardCacheFDCount(), initialFdCount, "should drop the cache file, if any.");
+
+      Services.clipboard.setData(Transfer, null, Services.clipboard.kGlobalClipboard);
+      is(getClipboardCacheFDCount(), initialFdCount, "should postsanitize the environment");
+    }
+
+    SimpleTest.finish();
+  }
+  ]]>
+  </script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=1123480"
+     target="_blank">Mozilla Bug 1123480</a>
+  </body>
+</window>
diff --git a/widget/tests/test_bug343416.xhtml b/widget/tests/test_bug343416.xhtml
new file mode 100644
index 0000000000..bf4dbbb9b4
--- /dev/null
+++ b/widget/tests/test_bug343416.xhtml
@@ -0,0 +1,191 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=343416
+-->
+<window title="Mozilla Bug 343416"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=343416">Mozilla Bug 343416</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+/** Test for Bug 343416 */
+SimpleTest.waitForExplicitFinish();
+
+// Observer:
+var idleObserver =
+{
+    QueryInterface: ChromeUtils.generateQI(["nsIObserver"]),
+    observe: function _observe(subject, topic, data)
+    {
+        if (topic != "idle")
+            return;
+
+//        var diff = Math.abs(data - newIdleSeconds * 1000);
+//        ok (diff < 5000, "The idle time should have increased by roughly 6 seconds, " +
+//                         "as that's when we told this listener to fire.");
+//        if (diff >= 5000)
+//            alert(data + "  " + newIdleSeconds);
+
+        // Attempt to get to the nsIUserIdleService        
+        var subjectOK = false;
+        try {
+            var idleService = subject.QueryInterface(nsIUserIdleService);
+            subjectOK = true;
+        }
+        catch (ex)
+        {}
+        ok(subjectOK, "The subject of the notification should be the " +
+                      "nsIUserIdleService.");
+
+        // Attempt to remove ourselves.
+        var removedObserver = false;
+        try {
+            idleService.removeIdleObserver(this, newIdleSeconds);
+            removedObserver = true;
+        }
+        catch (ex)
+        {}
+        ok(removedObserver, "We should be able to remove our observer here.");
+        finishedListenerOK = true;
+        if (finishedTimeoutOK)
+        {
+            clearTimeout(testBailout);
+            finishThisTest();
+        }
+    }
+};
+
+
+const nsIUserIdleService = Ci.nsIUserIdleService;
+const nsIISCID = "@mozilla.org/widget/useridleservice;1";
+var idleService = null;
+try
+{
+    idleService = Cc[nsIISCID].getService(nsIUserIdleService);
+}
+catch (ex)
+{}
+
+ok(idleService, "nsIUserIdleService should exist and be implemented on all tier 1 platforms.");
+
+var idleTime = null;
+var gotIdleTime = false;
+try
+{
+    idleTime = idleService.idleTime;
+    gotIdleTime = true;
+}
+catch (ex)
+{}
+
+ok (gotIdleTime, "Getting the idle time should not fail " +
+                 "in normal circumstances on any tier 1 platform.");
+
+// Now we set up a timeout to sanity-test the idleTime after 5 seconds
+setTimeout(testIdleTime, 5000);
+var startTimeStamp = Date.now();
+
+// Now we add the listener:
+var newIdleSeconds = Math.floor(idleTime / 1000) + 6;
+var addedObserver = false;
+try
+{
+    idleService.addIdleObserver(idleObserver, newIdleSeconds);
+    addedObserver = true;
+}
+catch (ex)
+{}
+
+ok(addedObserver, "The nsIUserIdleService should allow us to add an observer.");
+
+addedObserver = false;
+try
+{
+    idleService.addIdleObserver(idleObserver, newIdleSeconds);
+    addedObserver = true;
+}
+catch (ex)
+{}
+
+ok(addedObserver, "The nsIUserIdleService should allow us to add the same observer again.");
+
+var removedObserver = false;
+try
+{
+    idleService.removeIdleObserver(idleObserver, newIdleSeconds);
+    removedObserver = true;
+}
+catch (ex)
+{}
+
+ok(removedObserver, "The nsIUserIdleService should allow us to remove the observer just once.");
+
+function testIdleTime()
+{
+    /* eslint-disable-next-line no-shadow */
+    var gotIdleTime = false
+    try
+    {
+        var newIdleTime = idleService.idleTime;
+    gotIdleTime = true
+    }
+    catch (ex)
+    {}
+    ok(gotIdleTime, "Getting the idle time should not fail " +
+                    "in normal circumstances on any tier 1 platform.");
+    // Get the time difference, remove the approx. 5 seconds that we've waited,
+    // should be very close to 0 left.
+    var timeDiff = Math.abs((newIdleTime - idleTime) -
+                            (Date.now() - startTimeStamp));
+
+    // 1.5 second leniency.
+    ok(timeDiff < 1500, "The idle time should have increased by roughly the " +
+                        "amount of time it took for the timeout to fire. " +
+                        "You didn't touch the mouse or keyboard during the " +
+                        "test did you?");
+    finishedTimeoutOK = true;
+}
+
+// make sure we still exit when the listener and/or setTimeout don't fire:
+var testBailout = setTimeout(finishThisTest, 12000);
+var finishedTimeoutOK = false, finishedListenerOK = false;
+function finishThisTest()
+{
+    ok(finishedTimeoutOK, "We set a timeout and it should have fired by now.");
+    ok(finishedListenerOK, "We added a listener and it should have been called by now.");
+    if (!finishedListenerOK)
+    {
+        var removedListener = false;
+        try
+        {
+            idleService.removeIdleObserver(idleObserver, newIdleSeconds);
+            removedListener = true;
+        }
+        catch (ex)
+        {}
+    
+        ok(removedListener, "We added a listener and we should be able to remove it.");
+    }
+    // Done:
+    SimpleTest.finish();
+}
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_bug428405.xhtml b/widget/tests/test_bug428405.xhtml
new file mode 100644
index 0000000000..25d796ab7b
--- /dev/null
+++ b/widget/tests/test_bug428405.xhtml
@@ -0,0 +1,168 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css" type="text/css"?>
+
+<window id="window1" title="Test Bug 428405"
+  onload="setGlobals(); loadFirstTab();"
+  xmlns:html="http://www.w3.org/1999/xhtml"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"/>
+  <script src="chrome://mochikit/content/tests/SimpleTest/NativeKeyCodes.js"/>
+
+  <tabbox id="tabbox" style="-moz-box-flex: 100">
+    <tabs>
+      <tab label="Tab 1"/>
+      <tab label="Tab 2"/>
+    </tabs>
+    <tabpanels style="-moz-box-flex: 100">
+      <browser onload="configureFirstTab();" id="tab1browser" style="-moz-box-flex: 100"/>
+      <browser onload="configureSecondTab();" id="tab2browser" style="-moz-box-flex: 100"/>
+    </tabpanels>
+  </tabbox>
+
+  <script type="application/javascript"><![CDATA[
+    const {BrowserTestUtils} = ChromeUtils.importESModule(
+      "resource://testing-common/BrowserTestUtils.sys.mjs"
+    );
+
+    SimpleTest.waitForExplicitFinish();
+
+    var gCmdOptYReceived = false;
+
+    // Look for a cmd-opt-y event.
+    function onKeyPress(aEvent) {
+      gCmdOptYReceived = false;
+      if (String.fromCharCode(aEvent.charCode) != 'y')
+        return;
+      if (aEvent.ctrlKey || aEvent.shiftKey || !aEvent.metaKey || !aEvent.altKey)
+        return;
+      gCmdOptYReceived = true;
+    }
+
+    function setGlobals() {
+      let chromeWindow = Services.wm.getMostRecentWindow("navigator:browser");
+      // For some reason, a global <key> element's oncommand handler only gets
+      // invoked if the focus is outside both of the <browser> elements
+      // (tab1browser and tab2browser).  So, to make sure we can see a
+      // cmd-opt-y event in window1 (if one is available), regardless of where
+      // the focus is in this window, we need to add a "keypress" event
+      // listener to gChromeWindow, and then check (in onKeyPress()) to see if
+      // it's a cmd-opt-y event.
+      chromeWindow.addEventListener("keypress", onKeyPress);
+    }
+
+    // 1) Start loading first tab.
+    // 6) Start reloading first tab.
+    function loadFirstTab() {
+      var browser = document.getElementById("tab1browser");
+      BrowserTestUtils.startLoadingURIString(browser, "data:text/html;charset=utf-8,<body><h2>First Tab</h2><p><input type='submit' value='Button' id='button1'/></body>");
+    }
+
+    function configureFirstTab() {
+      try {
+        var button = document.getElementById("tab1browser").contentDocument.getElementById("button1");
+        button.addEventListener("click", onFirstTabButtonClicked);
+        button.focus();
+        if (document.getElementById("tabbox").selectedIndex == 0) {
+          // 2) When first tab has finished loading (while first tab is
+          //    focused), hit Return to trigger the action of first tab's
+          //    button.
+          synthesizeNativeReturnKey();
+        } else {
+          // 7) When first tab has finished reloading (while second tab is
+          //    focused), start loading second tab.
+          loadSecondTab();
+        }
+      } catch(e) {
+      }
+    }
+
+    // 8) Start loading second tab.
+    function loadSecondTab() {
+      var browser = document.getElementById("tab2browser");
+      BrowserTestUtils.startLoadingURIString(browser, "data:text/html;charset=utf-8,<body><h2>Second Tab</h2><p><input type='submit' value='Button' id='button1'/></body>");
+    }
+
+    function configureSecondTab() {
+      try {
+        var button = document.getElementById("tab2browser").contentDocument.getElementById("button1");
+        button.addEventListener("click", onSecondTabButtonClicked);
+        button.focus();
+        if (document.getElementById("tabbox").selectedIndex == 1) {
+          // 9) When second tab has finished loading (while second tab is
+          //    focused), hit Return to trigger action of second tab's
+          //    button.
+          synthesizeNativeReturnKey();
+        }
+      } catch(e) {
+      }
+    }
+
+    // 3) First tab's button clicked.
+    function onFirstTabButtonClicked() {
+      switchToSecondTabAndReloadFirst();
+    }
+
+    // 10) Second tab's button clicked.
+    function onSecondTabButtonClicked() {
+      switchToFirstTab();
+    }
+
+    function switchToSecondTabAndReloadFirst() {
+      // 4) Switch to second tab.
+      document.getElementById("tabbox").selectedIndex = 1;
+      // 5) Start reloading first tab (while second tab is focused).
+      loadFirstTab();
+    }
+
+    function switchToFirstTab() {
+      // 11) Switch back to first tab.
+      document.getElementById("tabbox").selectedIndex = 0;
+      doCmdY();
+    }
+
+    function doCmdY() {
+      // 12) Back in first tab, try cmd-y.
+      gCmdOptYReceived = false;
+      if (!synthesizeNativeCmdOptY(finishTest)) {
+        ok(false, "Failed to synthesize native key");
+        finishTest();
+      }
+    }
+
+    function finishTest() {
+      // 13) Check result.
+      is(gCmdOptYReceived, true);
+
+      SimpleTest.finish();
+    }
+
+    // synthesizeNativeReturnKey() and synthesizeNativeCmdOptY() are needed
+    // because their synthesizeKey() counterparts don't work properly -- the
+    // latter make this test succeed when it should fail.
+
+    // The 'aNativeKeyCode', 'aCharacters' and 'aUnmodifiedCharacters'
+    // parameters used below (in synthesizeNativeReturnKey() and
+    // synthesizeNativeCmdOptY()) were confirmed accurate using the
+    // DebugEventsPlugin v1.01 from bmo bug 441880.
+
+    function synthesizeNativeReturnKey() {
+      synthesizeNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_Return, {}, "\u000a", "\u000a");
+    }
+
+    function synthesizeNativeCmdOptY(aCallback) {
+      return synthesizeNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_Y, {metaKey:1, altKey:1}, "y", "y", aCallback);
+    }
+
+  ]]></script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <p id="display"></p>
+    <div id="content" style="display: none"></div>
+    <pre id="test"></pre>
+  </body>
+
+</window>
diff --git a/widget/tests/test_bug429954.xhtml b/widget/tests/test_bug429954.xhtml
new file mode 100644
index 0000000000..40de88cd32
--- /dev/null
+++ b/widget/tests/test_bug429954.xhtml
@@ -0,0 +1,42 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=429954
+-->
+<window title="Mozilla Bug 429954"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+
+SimpleTest.waitForFocus(function () {
+  var win = Services.wm.getMostRecentWindow("navigator:browser");
+  win.maximize();
+  var maxX = win.screenX, maxY = win.screenY;
+  var maxWidth = win.outerWidth, maxHeight = win.outerHeight;
+  win.restore();
+
+  window.openDialog("window_bug429954.xhtml", "_blank", 
+                    "chrome,noopener,resizable,width=" + maxWidth + ",height=" + maxHeight +
+                    ",screenX=" + maxX + "screenY=" + maxY,
+                    window);
+});
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_bug444800.xhtml b/widget/tests/test_bug444800.xhtml
new file mode 100644
index 0000000000..f6d3535d72
--- /dev/null
+++ b/widget/tests/test_bug444800.xhtml
@@ -0,0 +1,97 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin"
+                 type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=444800
+-->
+<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        title="Mozilla Bug 444800" onload="initAndRunTests()">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=444800"
+     target="_blank">Mozilla Bug 444800</a>
+  <p/>
+  <img id="bitmapImage" src="data:image/bmp;base64,Qk2KAwAAAAAAAIoAAAB8AAAADwAAABAAAAABABgAAAAAAAADAAASCwAAEgsAAAAAAAAAAAAAAAD%2FAAD%2FAAD%2FAAAAAAAA%2FwEAAAAAAAAAAAAAAAEAAAAAAAAAAAAAAAEAAAAAAAAAAAAAAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F0vf%2FAABc8tKY%2F%2F%2F%2FyNfq3Mi9%2F%2F%2F70vf%2FAABP8s2R%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2Fzff%2FAABB8s2R5f%2F%2FAAB5LgAA%2F%2B7Czff%2FAABB7s2R%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2Fzff%2FAABB99KRpdz%2FAAAAAAAA4Ktm0vv%2FAABB7s2R%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2Fzff%2FAABB7teYQZHNkS4AebfImAAA1%2FfyAABP7s2R%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2Fzff%2FAABByMiYAAB5159P0v%2F%2FAABBwtKrAABc7s2R%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2Fzff%2FAABPcIJwAAAA%2B%2BW3%2F%2F%2F%2FAHC3gnBBAABP7s2R%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2Fzff%2FAABcAAAAmE8A%2F%2F%2Fy%2F%2F%2F%2Fn9LyAAAAAAAA7s2Y%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FzfL%2FAABcAAAA4LFw%2F%2F%2F%2F%2F%2F%2F%2F4P%2F%2FAAB5AAAA7s2R%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F0vf%2FAABmXAAA%2F%2B7I%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FXJ%2FSAAAA8s2Y%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FAAAA%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FAAAA"/>
+  <p/>
+  <pre id="test">
+  </pre>
+  </body>
+
+  <script class="testbody" type="application/javascript">
+  <![CDATA[
+const knsIClipboard = Ci.nsIClipboard;
+
+function copyImageToClipboard()
+{
+  SpecialPowers.setCommandNode(window, document.getElementById("bitmapImage"));
+
+  const kCmd = "cmd_copyImageContents";
+  var controller = top.document.commandDispatcher
+                   .getControllerForCommand(kCmd);
+  ok((controller && controller.isCommandEnabled(kCmd)), "have copy command");
+  controller.doCommand(kCmd);
+
+  SpecialPowers.setCommandNode(window, null);
+}
+
+function getLoadContext() {
+  return window.docShell.QueryInterface(Ci.nsILoadContext);
+}
+
+function runImageClipboardTests(aCBSvc, aImageType)
+{
+  // Verify that hasDataMatchingFlavors() is working correctly.
+  var typeArray = [ aImageType ];
+  var hasImage = aCBSvc.hasDataMatchingFlavors(typeArray,
+                                               knsIClipboard.kGlobalClipboard);
+  ok(hasImage, aImageType + " - hasDataMatchingFlavors()");
+
+  // Verify that getData() is working correctly.
+  var xfer = Cc["@mozilla.org/widget/transferable;1"]
+               .createInstance(Ci.nsITransferable);
+  xfer.init(getLoadContext());
+  xfer.addDataFlavor(aImageType);
+  aCBSvc.getData(xfer, knsIClipboard.kGlobalClipboard, SpecialPowers.wrap(window).browsingContext.currentWindowContext);
+
+  var typeObj = {}, dataObj = {};
+  xfer.getAnyTransferData(typeObj, dataObj);
+  var gotValue = (null != dataObj.value);
+  ok(gotValue, aImageType + " - getData() returned a value");
+  if (gotValue)
+  {
+    const knsIInputStream = Ci.nsIInputStream;
+    var imgStream = dataObj.value.QueryInterface(knsIInputStream);
+    ok((null != imgStream), aImageType + " - got an nsIInputStream");
+    var bytesAvailable = imgStream.available();
+    ok((bytesAvailable > 10), aImageType + " - got some data");
+  }
+}
+
+function initAndRunTests()
+{
+  SimpleTest.waitForExplicitFinish();
+
+  copyImageToClipboard();
+
+  var cbSvc = Cc["@mozilla.org/widget/clipboard;1"]
+                .getService(knsIClipboard);
+
+  // Work around a problem on Windows where clipboard is not ready after copy.
+  setTimeout(function() { runTests(cbSvc); }, 0);
+}
+
+function runTests(aCBSvc)
+{
+  runImageClipboardTests(aCBSvc, "image/png");
+  runImageClipboardTests(aCBSvc, "image/jpg");
+  runImageClipboardTests(aCBSvc, "image/jpeg");
+
+  SimpleTest.finish();
+}
+
+]]>
+</script>
+</window>
diff --git a/widget/tests/test_bug466599.xhtml b/widget/tests/test_bug466599.xhtml
new file mode 100644
index 0000000000..95b3593437
--- /dev/null
+++ b/widget/tests/test_bug466599.xhtml
@@ -0,0 +1,102 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=466599
+-->
+<window title="Mozilla Bug 466599"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        onload="initAndRunTests()">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <p id="display"></p>
+    <div id="content" style="display: none"></div>
+    <pre id="test"></pre>
+  </body>
+
+  <!-- test code goes here -->
+  <script class="testbody" type="application/javascript">
+  <![CDATA[
+
+  /** Test for Bug 466599 */
+
+function getLoadContext() {
+  return window.docShell.QueryInterface(Ci.nsILoadContext);
+}
+
+function copyToClipboard(txt)
+{
+  var clipid = Ci.nsIClipboard;
+  var clip =
+    Cc['@mozilla.org/widget/clipboard;1'].createInstance(clipid);
+  if (!clip)
+    return false;
+  var trans =
+    Cc['@mozilla.org/widget/transferable;1'].createInstance(Ci.nsITransferable);
+  if (!trans)
+    return false;
+  trans.init(getLoadContext());
+  trans.addDataFlavor('text/html');
+  var str =
+    Cc['@mozilla.org/supports-string;1'].createInstance(Ci.nsISupportsString);
+  var copytext = txt;
+  str.data = copytext;
+  trans.setTransferData("text/html",str);
+  if (!clip)
+    return false;
+  clip.setData(trans,null,clipid.kGlobalClipboard);
+  return true;
+}
+
+function readFromClipboard()
+{
+  var clipid = Ci.nsIClipboard;
+  var clip =
+    Cc['@mozilla.org/widget/clipboard;1'].createInstance(clipid);
+  if (!clip)
+    return "";
+  var trans =
+    Cc['@mozilla.org/widget/transferable;1'].createInstance(Ci.nsITransferable);
+  if (!trans)
+    return "";
+  trans.init(getLoadContext());
+  trans.addDataFlavor('text/html');
+  clip.getData(trans, clipid.kGlobalClipboard, SpecialPowers.wrap(window).browsingContext.currentWindowContext);
+  var str = {};
+  trans.getTransferData("text/html",str);
+  if (str)
+    str = str.value.QueryInterface(Ci.nsISupportsString);
+  return str?.data;
+}
+
+function encodeHtmlEntities(s)
+{
+  var result = '';
+  for (var i = 0; i < s.length; i++) {
+    var c = s.charAt(i);
+    result += {'<':'&lt;', '>':'&gt;', '&':'&amp;', '"':'&quot;'}[c] || c;
+  }
+  return result;
+}
+
+function initAndRunTests()
+{
+  var source = '<p>Lorem ipsum</p>';
+  var expect = new RegExp('<html>.*charset=utf-8.*' + source + '.*</html>', 'im');
+
+  var result = copyToClipboard(source);
+  ok(result, "copied HTML data to system pasteboard");
+
+  result = readFromClipboard();
+  ok(expect.test(result), "data on system pasteboard is wrapped with charset metadata");
+
+  $("display").innerHTML =
+    '<em>source:</em> <pre>' + encodeHtmlEntities(source) + '</pre><br/>' +
+    '<em>result:</em> <pre>' + encodeHtmlEntities(result) + '</pre>';
+}
+
+  ]]>
+  </script>
+</window>
diff --git a/widget/tests/test_bug478536.xhtml b/widget/tests/test_bug478536.xhtml
new file mode 100644
index 0000000000..383c0bb42f
--- /dev/null
+++ b/widget/tests/test_bug478536.xhtml
@@ -0,0 +1,33 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=478536
+-->
+<window title="Mozilla Bug 478536"
+  xmlns:html="http://www.w3.org/1999/xhtml"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <title>Test for Bug 478536</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+window.openDialog("window_bug478536.xhtml", "_blank", 
+                  "chrome,width=600,height=600,noopener", window);
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_bug485118.xhtml b/widget/tests/test_bug485118.xhtml
new file mode 100644
index 0000000000..5c635f2982
--- /dev/null
+++ b/widget/tests/test_bug485118.xhtml
@@ -0,0 +1,72 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=485118
+-->
+<window title="Mozilla Bug 485118"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<hbox height="300">
+  <vbox width="300">
+    <scrollbar orient="horizontal"
+               maxpos="10000"
+               pageincrement="1"
+               id="horizontal"/>
+    <scrollbar orient="horizontal"
+               maxpos="10000"
+               pageincrement="1"
+               style="appearance: auto; -moz-default-appearance: scrollbar-small;"
+               id="horizontalSmall"/>
+    <hbox flex="1">
+      <scrollbar orient="vertical"
+                 maxpos="10000"
+                 pageincrement="1"
+                 id="vertical"/>
+      <scrollbar orient="vertical"
+                 maxpos="10000"
+                 pageincrement="1"
+                 style="appearance: auto; -moz-default-appearance: scrollbar-small;"
+                 id="verticalSmall"/>
+      <spacer flex="1"/>
+    </hbox>
+  </vbox>
+</hbox>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+
+function runTest() {
+  ["horizontal", "vertical"].forEach(function (orient) {
+    ["", "Small"].forEach(function (size) {
+      var elem = document.getElementById(orient + size);
+      var thumbRect = SpecialPowers.unwrap(
+        SpecialPowers.InspectorUtils.getChildrenForNode(elem, true, false)[0])
+        .childNodes[0].getBoundingClientRect();
+      var sizeToCheck = orient == "horizontal" ? "width" : "height";
+      // var expectedSize = size == "Small" ? 19 : 26;
+      var expectedSize = 26;
+      is(thumbRect[sizeToCheck], expectedSize, size + " scrollbar has wrong minimum " + sizeToCheck);
+    });
+  });
+  SimpleTest.finish();
+}
+window.addEventListener("load", runTest);
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_bug517396.xhtml b/widget/tests/test_bug517396.xhtml
new file mode 100644
index 0000000000..c88baf49ab
--- /dev/null
+++ b/widget/tests/test_bug517396.xhtml
@@ -0,0 +1,53 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=517396
+-->
+<window title="Mozilla Bug 517396"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+
+SimpleTest.waitForFocus(function () {
+   // this test fails on Linux, bug 526236
+  if (navigator.platform.includes("Lin")) {
+    ok(true, "disabled on Linux");
+    SimpleTest.finish();
+    return;
+  }
+
+  var win = Services.wm.getMostRecentWindow("navigator:browser");
+  var oldWidth = win.outerWidth, oldHeight = win.outerHeight;
+  win.maximize();
+  var newWidth = win.outerWidth, newHeight = win.outerHeight;
+  win.moveBy(10, 0);
+  var sizeShouldHaveChanged = !navigator.platform.match(/Mac/);
+  var compFunc = sizeShouldHaveChanged ? isnot : is;
+  var not = sizeShouldHaveChanged ? "" : "not ";
+  compFunc(win.outerWidth, newWidth, "moving a maximized window should " + not + "have changed its width");
+  compFunc(win.outerHeight, newHeight, "moving a maximized window should " + not + "have changed its height");
+  win.restore();
+  is(win.outerWidth, oldWidth, "restored window has wrong width");
+  is(win.outerHeight, oldHeight, "restored window has wrong height");
+  SimpleTest.finish();
+});
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_bug522217.xhtml b/widget/tests/test_bug522217.xhtml
new file mode 100644
index 0000000000..0fa55a65e8
--- /dev/null
+++ b/widget/tests/test_bug522217.xhtml
@@ -0,0 +1,35 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=522217
+-->
+<window title="Mozilla Bug 522217"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+
+SimpleTest.waitForFocus(function () {
+  window.openDialog("window_bug522217.xhtml", "_blank", 
+                    "chrome,resizable,width=400,height=300,noopener", window);
+});
+
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_bug538242.xhtml b/widget/tests/test_bug538242.xhtml
new file mode 100644
index 0000000000..4608a74e35
--- /dev/null
+++ b/widget/tests/test_bug538242.xhtml
@@ -0,0 +1,55 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=538242
+-->
+<window title="Mozilla Bug 538242"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+if (navigator.platform.startsWith("Win")) {
+  SimpleTest.expectAssertions(0, 1);
+}
+
+SimpleTest.waitForExplicitFinish();
+
+SimpleTest.waitForFocus(function () {
+  if (navigator.platform.includes("Lin")) {
+    ok(true, "This test is disabled on Linux because it expects moving windows to be synchronous which is not guaranteed on Linux.");
+    SimpleTest.finish();
+    return;
+  }
+
+  var win = window.browsingContext.topChromeWindow.open(
+      "window_bug538242.xhtml", "_blank", 
+      "chrome,width=400,height=300,left=100,top=100");
+  SimpleTest.waitForFocus(function () {
+    is(win.screenX, 100, "window should open at 100, 100");
+    is(win.screenY, 100, "window should open at 100, 100");
+    var [oldX, oldY] = [win.screenX, win.screenY];
+    win.moveTo(0, 0);
+    isnot(win.screenX, oldX, "window should have moved to a point near 0, 0");
+    isnot(win.screenY, oldY, "window should have moved to a point near 0, 0");
+    win.close();
+    SimpleTest.finish();
+  }, win);
+});
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_bug565392.html b/widget/tests/test_bug565392.html
new file mode 100644
index 0000000000..b50053f23a
--- /dev/null
+++ b/widget/tests/test_bug565392.html
@@ -0,0 +1,62 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=565392
+-->
+<head>
+  <title>Test for Bug 565392</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=565392">Mozilla Bug 565392</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script type="application/javascript">
+
+/** Test for Bug 565392 */
+
+var dir1 = Services.dirsvc.get("ProfD", Ci.nsIFile);
+var clipboard = Services.clipboard;
+
+  function getLoadContext() {
+    return window.docShell.QueryInterface(Ci.nsILoadContext);
+  }
+
+  function getTransferableFile(file) {
+    var transferable = Cc["@mozilla.org/widget/transferable;1"]
+                         .createInstance(Ci.nsITransferable);
+    transferable.init(getLoadContext());
+    transferable.setTransferData("application/x-moz-file", file);
+    return transferable;
+  }
+
+  function setClipboardData(transferable) {
+    clipboard.setData(transferable, null, 1);
+  }
+
+  function getClipboardData(mime) {
+    var transferable = Cc["@mozilla.org/widget/transferable;1"]
+                         .createInstance(Ci.nsITransferable);
+    transferable.init(getLoadContext());
+    transferable.addDataFlavor(mime);
+    clipboard.getData(transferable, 1, SpecialPowers.wrap(window).browsingContext.currentWindowContext);
+    var data = {};
+    transferable.getTransferData(mime, data);
+    return data;
+  }
+
+setClipboardData(getTransferableFile(dir1));
+is(clipboard.hasDataMatchingFlavors(["application/x-moz-file"], 1), true);
+var data = getClipboardData("application/x-moz-file");
+var file = data.value.QueryInterface(Ci.nsIFile);
+ok(file.isDirectory(), true);
+is(file.target, dir1.target, true);
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/widget/tests/test_bug586713.xhtml b/widget/tests/test_bug586713.xhtml
new file mode 100644
index 0000000000..4733202264
--- /dev/null
+++ b/widget/tests/test_bug586713.xhtml
@@ -0,0 +1,29 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Native menu system tests"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+window.openDialog("bug586713_window.xhtml", "bug586713_window", 
+                  "chrome,width=600,height=600,noopener", window);
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_bug593307.xhtml b/widget/tests/test_bug593307.xhtml
new file mode 100644
index 0000000000..770dd390cb
--- /dev/null
+++ b/widget/tests/test_bug593307.xhtml
@@ -0,0 +1,40 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=593307
+-->
+<window title="Mozilla Bug 593307"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+
+function finish() {
+  offscreenWindow.close();
+  SimpleTest.finish();
+}
+
+var mainWindow = window.browsingContext.topChromeWindow;
+
+var offscreenWindow = mainWindow.openDialog("window_bug593307_offscreen.xhtml", "",
+                                            "dialog=no,chrome,width=200,height=200,screenX=-3000,screenY=-3000",
+                                            SimpleTest, finish);
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_bug596600.xhtml b/widget/tests/test_bug596600.xhtml
new file mode 100644
index 0000000000..4acdab79bc
--- /dev/null
+++ b/widget/tests/test_bug596600.xhtml
@@ -0,0 +1,190 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Native mouse event tests"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+
+var gLeftWindow, gRightWindow, gBrowserElement;
+
+function openWindows() {
+  gLeftWindow = window.browsingContext.topChromeWindow
+                      .open('empty_window.xhtml', '_blank', 'chrome,screenX=50,screenY=50,width=200,height=200');
+  SimpleTest.waitForFocus(function () {
+    gRightWindow = window.browsingContext.topChromeWindow
+                         .open('empty_window.xhtml', '', 'chrome,screenX=300,screenY=50,width=200,height=200');
+    SimpleTest.waitForFocus(attachBrowserToLeftWindow, gRightWindow);
+  }, gLeftWindow);
+}
+
+function attachBrowserToLeftWindow() {
+  gBrowserElement = gLeftWindow.document.createXULElement("browser");
+  gBrowserElement.setAttribute("type", "content");
+  gBrowserElement.setAttribute("src", "file_bug596600.html");
+  gBrowserElement.style.width = "100px";
+  gBrowserElement.style.height = "100px";
+  gBrowserElement.style.margin = "50px";
+  gLeftWindow.document.documentElement.appendChild(gBrowserElement);
+  gBrowserElement.addEventListener("load", async () => {
+    await test1();
+    await test2();
+    gRightWindow.close();
+    gLeftWindow.close();
+    SimpleTest.finish();
+  }, { capture: true, once: true });
+}
+
+async function test1() {
+  // gRightWindow is active, gLeftWindow is inactive.
+  info(`Synthesizing native "mousemove" event at top-left of the screen...`);
+  await promiseNativeMouseEvent({
+    type: "mousemove",
+    screenX: 0,
+    screenY: 0,
+    scale: "inScreenPixels",
+  });
+  await new Promise(resolve => SimpleTest.executeSoon(resolve));
+
+  // Move into the left window
+  info(`Synthesizing native "mousemove" event in the left window (but outside the content)...`);
+  await promiseNativeMouseEventAndWaitForEvent({
+    type: "mousemove",
+    target: gBrowserElement,
+    offsetX: -20,
+    offsetY: -20,
+    win: gLeftWindow,
+    eventTypeToWait: "mouseover",
+    eventTargetToListen: gLeftWindow,
+  });
+  ok(true, `"mouseover" event is fired on the left window when cursor is moved into it`);
+
+  // Move over the browser
+  info(`Synthesizing native "mousemove" event on the content in the left window...`);
+  await promiseNativeMouseEventAndWaitForEvent({
+    type: "mousemove",
+    target: gBrowserElement,
+    atCenter: true,
+    win: gLeftWindow,
+    eventTypeToWait: "mouseout",
+    eventTargetToListen: gLeftWindow,
+  });
+  ok(true, `"mouseout" event is fired on the left window when cursor is moved into its child browser`);
+}
+
+async function test2() {
+  // Make the browser cover the whole window.
+  gBrowserElement.style.margin = "0";
+  gBrowserElement.style.width = gBrowserElement.style.height = "200px";
+
+  // Add a box to the browser at the left edge.
+  var doc = gBrowserElement.contentDocument;
+  var box = doc.createElement("div");
+  box.setAttribute("id", "box");
+  box.style.position = "absolute";
+  box.style.left = "0";
+  box.style.top = "50px";
+  box.style.width = "100px";
+  box.style.height = "100px";
+  box.style.backgroundColor = "green";
+  doc.body.appendChild(box);
+
+  ok(!box.matches(":hover"), "Box shouldn't be hovered (since the mouse isn't over it and since it's in a non-clickthrough browser in a background window)");
+
+  // A function to waitForFocus and then wait for synthetic mouse
+  // events to happen.  Note that those happen off the refresh driver,
+  // and happen after animation frame requests.
+  function changeFocusAndAwaitSyntheticMouse(winToFocus,
+                                             elementToWatchForMouseEventOn) {
+    return Promise.all([
+      new Promise(resolve => {
+        function mouseWatcher() {
+          elementToWatchForMouseEventOn.removeEventListener("mouseover",
+                                                            mouseWatcher);
+          elementToWatchForMouseEventOn.removeEventListener("mouseout",
+                                                            mouseWatcher);
+          SimpleTest.executeSoon(resolve);
+        }
+        elementToWatchForMouseEventOn.addEventListener("mouseover",
+                                                      mouseWatcher);
+        elementToWatchForMouseEventOn.addEventListener("mouseout",
+                                                      mouseWatcher);
+      }),
+      new Promise(resolve => SimpleTest.waitForFocus(resolve, winToFocus)),
+    ]);
+  }
+
+  // Move the mouse over the box.
+  info(`Synthesizing native "mousemove" event into the box...`);
+  await promiseNativeMouseEvent({
+    type: "mousemove",
+    target: box,
+    atCenter: true,
+    win: gLeftWindow,
+  });
+  await new Promise(resolve =>
+    requestAnimationFrame(() => SimpleTest.executeSoon(resolve))
+  );
+  // XXX We cannot guarantee that the native mousemouse have already handled here.
+  ok(!box.matches(":hover"), "Box shouldn't be hovered (since it's in a non-clickthrough browser in a background window)");
+
+  // Activate the left window.
+  info("Waiting the left window activated...");
+  await changeFocusAndAwaitSyntheticMouse(gLeftWindow, box);
+  ok(gBrowserElement.matches(":hover"), "browser should be hovered");
+  ok(box.matches(":hover"), "Box should be hovered");
+
+  // De-activate the window (by activating the right window).
+  info("Waiting the right window activated...");
+  await changeFocusAndAwaitSyntheticMouse(gRightWindow, box);
+  ok(!gBrowserElement.matches(":hover"), "browser shouldn't be hovered");
+  ok(!box.matches(":hover"), "Box shouldn't be hovered");
+
+  // Re-activate it.
+  info("Waiting the left window activated again...");
+  await changeFocusAndAwaitSyntheticMouse(gLeftWindow, box);
+  ok(gBrowserElement.matches(":hover"), "browser should be hovered");
+  ok(box.matches(":hover"), "Box should be hovered");
+
+  // Unhover the box and the left window.
+  info(`Synthesizing native "mousemove" event outside the box and the left window...`);
+  await promiseNativeMouseEventAndWaitForEvent({
+    type: "mousemove",
+    screenX: 0,
+    screenY: 0,
+    scale: "inScreenPixels",
+    win: gLeftWindow,
+    eventTargetToListen: box,
+    eventTypeToWait: "mouseout",
+  });
+  await new Promise(resolve =>
+    requestAnimationFrame(() => SimpleTest.executeSoon(resolve))
+  );
+
+  ok(!gBrowserElement.matches(":hover"), "browser shouldn't be hovered");
+  ok(!box.matches(":hover"), "box shouldn't be hovered");
+}
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.waitForFocus(openWindows);
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_bug673301.xhtml b/widget/tests/test_bug673301.xhtml
new file mode 100644
index 0000000000..663f18397e
--- /dev/null
+++ b/widget/tests/test_bug673301.xhtml
@@ -0,0 +1,33 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+
+<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+<script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<p id="display"></p>
+<div id="content" style="display: none"/>
+</body>
+
+<script type="application/javascript">
+function getLoadContext() {
+  return window.docShell.QueryInterface(Ci.nsILoadContext);
+}
+
+var transferable = Cc['@mozilla.org/widget/transferable;1']
+                             .createInstance(Ci.nsITransferable);
+transferable.init(getLoadContext());
+
+transferable.addDataFlavor("text/plain");
+transferable.setTransferData("text/plain", document);
+
+Services.clipboard.setData(transferable, null, Ci.nsIClipboard.kGlobalClipboard);
+
+transferable.setTransferData("text/plain", null);
+
+SimpleTest.ok(true, "Didn't crash setting non-text data for text/plain type");
+</script>
+</window>
diff --git a/widget/tests/test_bug760802.xhtml b/widget/tests/test_bug760802.xhtml
new file mode 100644
index 0000000000..831b4dea93
--- /dev/null
+++ b/widget/tests/test_bug760802.xhtml
@@ -0,0 +1,81 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=760802
+-->
+<window title="Mozilla Bug 760802"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=760802"
+     target="_blank">Mozilla Bug 760802</a>
+  <p id="display"></p>
+  <div id="content" style="display: none"/>
+  <iframe id="iframe_not_editable" width="300" height="150"
+          src="data:text/html,&lt;html&gt;&lt;body&gt;&lt;/body&gt;&lt;/html&gt;"/><br/>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript"><![CDATA[
+SimpleTest.waitForExplicitFinish();
+
+function getBaseWindowInterface(win) {
+  return win.docShell
+    .treeOwner
+    .nsIBaseWindow;
+}
+
+function getBaseWindowInterfaceFromDocShell(win) {
+  return win.docShell.QueryInterface(Ci.nsIBaseWindow);
+}
+
+function shouldThrowException(fun, exception) {
+  try {
+    fun.call();
+    return false;
+  } catch (e) {
+    $("display").innerHTML += "<br/>OK thrown: "+e.message;
+    return (e instanceof Components.Exception &&
+            e.result === exception)
+  }
+}
+function doesntThrowException(fun) {
+  return !shouldThrowException(fun);
+}
+
+var baseWindow = getBaseWindowInterface(this);
+var nativeHandle = baseWindow.nativeHandle;
+$("display").innerHTML = "found nativeHandle for this window: "+nativeHandle;
+
+var win = Services.wm.getMostRecentWindow("navigator:browser");
+let docShell = getBaseWindowInterfaceFromDocShell(win);
+
+ok(
+  shouldThrowException(function(){docShell.nativeHandle;},
+              Cr.NS_ERROR_NOT_IMPLEMENTED),
+  "nativeHandle should not be implemented for nsDocShell"
+);
+
+ok(typeof(nativeHandle) === "string", "nativeHandle should be a string");
+ok(nativeHandle.match(/^0x[0-9a-f]+$/), "nativeHandle should have a memory address format");
+
+var iWin = document.getElementById("iframe_not_editable").contentWindow;
+is(getBaseWindowInterface(iWin).nativeHandle, nativeHandle,
+   "the nativeHandle of an iframe should be its parent's nativeHandle");
+
+var dialog = win.openDialog("data:text/plain,this is an active window.", "_blank",
+                            "chrome,dialog=yes,width=100,height=100");
+
+isnot(getBaseWindowInterface(dialog).nativeHandle, "",
+      "the nativeHandle of a dialog should not be empty");
+
+dialog.close();
+
+todo(false, "the nativeHandle of a window without a mainWidget should be empty"); // how to build a window without a mainWidget ?
+
+SimpleTest.finish();
+  ]]></script>
+</window>
diff --git a/widget/tests/test_clipboard.html b/widget/tests/test_clipboard.html
new file mode 100644
index 0000000000..35ad84ad73
--- /dev/null
+++ b/widget/tests/test_clipboard.html
@@ -0,0 +1,16 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=948065
+-->
+<head>
+<title>Test for Bug 948065</title>
+<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<script src="clipboard_helper.js"></script>
+</head>
+<body>
+<!-- Tests are in file_test_clipboard.js -->
+<script src="file_test_clipboard.js"></script>
+</body>
+</html>
diff --git a/widget/tests/test_clipboard_asyncGetData.html b/widget/tests/test_clipboard_asyncGetData.html
new file mode 100644
index 0000000000..0cb3dc2aa1
--- /dev/null
+++ b/widget/tests/test_clipboard_asyncGetData.html
@@ -0,0 +1,19 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1852947
+-->
+<head>
+<title>Test for Bug 1852947</title>
+<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<script src="clipboard_helper.js"></script>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+<pre id="test"></pre>
+<!-- Tests are in file_clipboard_asyncGetData.js -->
+<script src="file_test_clipboard_asyncGetData.js"></script>
+</body>
+</html>
diff --git a/widget/tests/test_clipboard_asyncGetData_chrome.html b/widget/tests/test_clipboard_asyncGetData_chrome.html
new file mode 100644
index 0000000000..d4e44185a5
--- /dev/null
+++ b/widget/tests/test_clipboard_asyncGetData_chrome.html
@@ -0,0 +1,19 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1852947
+-->
+<head>
+<title>Test for Bug 1852947</title>
+<link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css" />
+<script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+<script src="clipboard_helper.js"></script>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+<pre id="test"></pre>
+<!-- Tests are in file_clipboard_asyncGetData.js -->
+<script src="file_test_clipboard_asyncGetData.js"></script>
+</body>
+</html>
diff --git a/widget/tests/test_clipboard_asyncSetData.html b/widget/tests/test_clipboard_asyncSetData.html
new file mode 100644
index 0000000000..05e2ca714b
--- /dev/null
+++ b/widget/tests/test_clipboard_asyncSetData.html
@@ -0,0 +1,19 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1712122
+-->
+<head>
+<title>Test for Bug 1712122</title>
+<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<script src="clipboard_helper.js"></script>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+<pre id="test"></pre>
+<!-- Tests are in file_test_clipboard_asyncSetData.js -->
+<script src="file_test_clipboard_asyncSetData.js"></script>
+</body>
+</html>
diff --git a/widget/tests/test_clipboard_asyncSetData_chrome.html b/widget/tests/test_clipboard_asyncSetData_chrome.html
new file mode 100644
index 0000000000..61afb9067b
--- /dev/null
+++ b/widget/tests/test_clipboard_asyncSetData_chrome.html
@@ -0,0 +1,19 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1712122
+-->
+<head>
+<title>Test for Bug 1712122</title>
+<link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css" />
+<script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+<script src="clipboard_helper.js"></script>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+<pre id="test"></pre>
+<!-- Tests are in file_test_clipboard_asyncSetData.js -->
+<script src="file_test_clipboard_asyncSetData.js"></script>
+</body>
+</html>
diff --git a/widget/tests/test_clipboard_cache_chrome.html b/widget/tests/test_clipboard_cache_chrome.html
new file mode 100644
index 0000000000..55b6d41589
--- /dev/null
+++ b/widget/tests/test_clipboard_cache_chrome.html
@@ -0,0 +1,231 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1812543
+-->
+<head>
+<title>Test for Bug 1812543</title>
+<link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css" />
+<script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+<script src="clipboard_helper.js"></script>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+<pre id="test"></pre>
+<script class="testbody" type="application/javascript">
+
+function testClipboardCache(aClipboardType, aAsync, aIsSupportGetFromCachedTransferable) {
+  add_task(function test_clipboard_get() {
+    info(`test_clipboard_get ${aAsync ? "async " : ""}` +
+         `with pref ${aIsSupportGetFromCachedTransferable ? "enabled" : "disabled"}`);
+
+    const string = generateRandomString();
+    const trans = generateNewTransferable("text/plain", string);
+
+    info(`Write text/plain data to clipboard ${aClipboardType}`);
+    if (aAsync) {
+      let request = clipboard.asyncSetData(aClipboardType);
+      request.setData(trans, null);
+    } else {
+      clipboard.setData(trans, null, aClipboardType);
+    }
+    is(getClipboardData("text/plain", aClipboardType), string,
+       `Check text/plain data on clipboard ${aClipboardType}`);
+
+    info(`Add text/foo data to transferable`);
+    addStringToTransferable("text/foo", string, trans);
+    // XXX macOS caches the transferable to implement kSelectionCache type, too,
+    // so it behaves differently than other types.
+    if (aClipboardType == clipboard.kSelectionCache && !aIsSupportGetFromCachedTransferable) {
+      todo_is(getClipboardData("text/foo", aClipboardType),
+              aIsSupportGetFromCachedTransferable ? string : null,
+              `Check text/foo data on clipboard ${aClipboardType}`);
+    } else {
+      is(getClipboardData("text/foo", aClipboardType),
+         aIsSupportGetFromCachedTransferable ? string : null,
+         `Check text/foo data on clipboard ${aClipboardType}`);
+    }
+
+    info(`Should not get the data from other clipboard type`);
+    clipboardTypes.forEach(function(otherType) {
+      if (otherType != aClipboardType &&
+          clipboard.isClipboardTypeSupported(otherType)) {
+        is(getClipboardData("text/plain", otherType), null,
+           `Check text/plain data on clipboard ${otherType}`);
+        is(getClipboardData("text/foo", otherType), null,
+           `Check text/foo data on clipboard ${otherType}`);
+
+        info(`Write text/plain data to clipboard ${otherType}`);
+        writeRandomStringToClipboard("text/plain", otherType);
+      }
+    });
+
+    info(`Check data on clipboard ${aClipboardType} again`);
+    is(getClipboardData("text/plain", aClipboardType), string,
+       `Check text/plain data on clipboard ${aClipboardType} again`);
+    // XXX macOS caches the transferable to implement kSelectionCache type, too,
+    // so it behaves differently than other types.
+    if (aClipboardType == clipboard.kSelectionCache && !aIsSupportGetFromCachedTransferable) {
+      todo_is(getClipboardData("text/foo", aClipboardType),
+              aIsSupportGetFromCachedTransferable ? string : null,
+              `Check text/foo data on clipboard ${aClipboardType} again`);
+    } else {
+      is(getClipboardData("text/foo", aClipboardType),
+         aIsSupportGetFromCachedTransferable ? string : null,
+         `Check text/foo data on clipboard ${aClipboardType} again`);
+    }
+
+    info(`Clean all clipboard data`);
+    cleanupAllClipboard();
+  });
+}
+
+function runClipboardCacheTests(aIsSupportGetFromCachedTransferable) {
+  add_task(async function setup() {
+    cleanupAllClipboard();
+    await SpecialPowers.pushPrefEnv({
+      set: [
+        [
+          "widget.clipboard.use-cached-data.enabled",
+          aIsSupportGetFromCachedTransferable,
+        ],
+      ],
+    });
+  });
+
+  clipboardTypes.forEach(function (type) {
+    if (!clipboard.isClipboardTypeSupported(type)) {
+      return;
+    }
+
+    add_task(function test_clipboard_hasDataMatchingFlavors() {
+      info(`test_clipboard_hasDataMatchingFlavors with pref ` +
+           `${aIsSupportGetFromCachedTransferable ? "enabled" : "disabled"}`);
+
+      const trans = generateNewTransferable("text/plain", generateRandomString());
+
+      info(`Write text/plain data to clipboard ${type}`);
+      clipboard.setData(trans, null, type);
+      ok(clipboard.hasDataMatchingFlavors(["text/plain"], type),
+         `Check if there is text/plain flavor on clipboard ${type}`);
+      ok(!clipboard.hasDataMatchingFlavors(["text/foo"], type),
+         `Check if there is text/foo flavor on clipboard ${type}`);
+
+      info(`Add text/foo data to transferable`);
+      addStringToTransferable("text/foo", generateRandomString(), trans);
+      ok(clipboard.hasDataMatchingFlavors(["text/plain"], type),
+         `Check if there is text/plain flavor on clipboard ${type}`);
+      // XXX macOS caches the transferable to implement kSelectionCache type, too,
+      // so it behaves differently than other types.
+      if (type == clipboard.kSelectionCache && !aIsSupportGetFromCachedTransferable) {
+        todo_is(clipboard.hasDataMatchingFlavors(["text/foo"], type),
+                aIsSupportGetFromCachedTransferable,
+                `Check if there is text/foo flavor on clipboard ${type}`);
+      } else {
+        is(clipboard.hasDataMatchingFlavors(["text/foo"], type),
+           aIsSupportGetFromCachedTransferable,
+           `Check if there is text/foo flavor on clipboard ${type}`);
+      }
+
+      // Check other clipboard types.
+      clipboardTypes.forEach(function(otherType) {
+        if (otherType != type &&
+            clipboard.isClipboardTypeSupported(otherType)) {
+          ok(!clipboard.hasDataMatchingFlavors(["text/plain"], otherType),
+             `Check if there is text/plain flavor on clipboard ${otherType}`);
+          ok(!clipboard.hasDataMatchingFlavors(["text/foo"], otherType),
+             `Check if there is text/foo flavor on clipboard ${otherType}`);
+
+          info(`Write text/plain data to clipboard ${otherType}`);
+          writeRandomStringToClipboard("text/plain", otherType);
+        }
+      });
+
+      // Check again.
+      ok(clipboard.hasDataMatchingFlavors(["text/plain"], type),
+         `Check if there is text/plain flavor on clipboard ${type}`);
+      // XXX macOS caches the transferable to implement kSelectionCache type, too,
+      // so it behaves differently than other types.
+      if (type == clipboard.kSelectionCache && !aIsSupportGetFromCachedTransferable) {
+        todo_is(clipboard.hasDataMatchingFlavors(["text/foo"], type),
+                aIsSupportGetFromCachedTransferable,
+                `Check if there is text/foo flavor on clipboard ${type}`);
+      } else {
+        is(clipboard.hasDataMatchingFlavors(["text/foo"], type),
+           aIsSupportGetFromCachedTransferable,
+           `Check if there is text/foo flavor on clipboard ${type}`);
+      }
+
+      info(`Write text/plain data to clipboard ${type} again`);
+      writeRandomStringToClipboard("text/plain", type);
+      ok(clipboard.hasDataMatchingFlavors(["text/plain"], type),
+         `Check if there is text/plain flavor on clipboard ${type}`);
+      ok(!clipboard.hasDataMatchingFlavors(["text/foo"], type),
+         `Check if there is text/foo flavor on clipboard ${type}`);
+
+      // Clean clipboard data.
+      cleanupAllClipboard();
+    });
+
+    add_task(async function test_clipboard_asyncGetData() {
+      const testClipboardData = async function(aRequest, aExpectedData) {
+        is(aRequest.flavorList.length, Object.keys(aExpectedData).length, "Check flavorList length");
+        for (const [key, value] of Object.entries(aExpectedData)) {
+          ok(aRequest.flavorList.includes(key), `${key} should be available`);
+          is(await asyncClipboardRequestGetData(aRequest, key), value,
+             `Check ${key} data`);
+        }
+      };
+
+      info(`test_clipboard_hasDataMatchingFlavors with pref ` +
+           `${aIsSupportGetFromCachedTransferable ? "enabled" : "disabled"}`);
+
+      const clipboardData = { "text/plain": generateRandomString() };
+      const trans = generateNewTransferable("text/plain", clipboardData["text/plain"]);
+
+      info(`Write text/plain data to clipboard ${type}`);
+      clipboard.setData(trans, null, type);
+      await testClipboardData(await asyncGetClipboardData(type), clipboardData);
+
+      info(`Add text/html data to transferable`);
+      const htmlString = `<div>${generateRandomString()}</div>`;
+      addStringToTransferable("text/html", htmlString, trans);
+      // XXX macOS uses cached transferable to implement kSelectionCache type, too,
+      // so it behaves differently than other types.
+      if (aIsSupportGetFromCachedTransferable ||
+          (type == clipboard.kSelectionCache && !SpecialPowers.isHeadless)) {
+        clipboardData["text/html"] = htmlString;
+      }
+      await testClipboardData(await asyncGetClipboardData(type), clipboardData);
+
+      info(`Should not get the data from other clipboard type`);
+      clipboardTypes.forEach(async function(otherType) {
+        if (otherType != type &&
+            clipboard.isClipboardTypeSupported(otherType)) {
+          info(`Check clipboard type ${otherType}`);
+          await testClipboardData(await asyncGetClipboardData(otherType), {});
+        }
+      });
+
+      info(`Check data on clipboard ${type} again`);
+      await testClipboardData(await asyncGetClipboardData(type), clipboardData);
+    });
+
+    // Test sync set clipboard data.
+    testClipboardCache(type, false, aIsSupportGetFromCachedTransferable);
+
+    // Test async set clipboard data.
+    testClipboardCache(type, true, aIsSupportGetFromCachedTransferable);
+});
+}
+
+// Test not get data from clipboard cache.
+runClipboardCacheTests(false);
+
+// Test get data from clipboard cache.
+runClipboardCacheTests(true);
+
+</script>
+</body>
+</html>
diff --git a/widget/tests/test_clipboard_chrome.html b/widget/tests/test_clipboard_chrome.html
new file mode 100644
index 0000000000..387e3975b3
--- /dev/null
+++ b/widget/tests/test_clipboard_chrome.html
@@ -0,0 +1,16 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=948065
+-->
+<head>
+<title>Test for Bug 948065</title>
+<link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css" />
+<script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+<script src="clipboard_helper.js"></script>
+</head>
+<body>
+<!-- Tests are in file_test_clipboard.js -->
+<script src="file_test_clipboard.js"></script>
+</body>
+</html>
diff --git a/widget/tests/test_clipboard_owner_chrome.html b/widget/tests/test_clipboard_owner_chrome.html
new file mode 100644
index 0000000000..4759b2b14c
--- /dev/null
+++ b/widget/tests/test_clipboard_owner_chrome.html
@@ -0,0 +1,75 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1812078
+-->
+<head>
+<title>Test for Bug 1812078</title>
+<link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css" />
+<script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+<script src="clipboard_helper.js"></script>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none"></div>
+<pre id="test"></pre>
+<script class="testbody" type="application/javascript">
+
+function testClipboardOwner(aClipboardType, aAsync) {
+  let losingOwnership = false;
+  const clipboardOwner = {
+    QueryInterface: ChromeUtils.generateQI(["nsIClipboardOwner"]),
+    // nsIClipboardOwner
+    LosingOwnership(aTransferable) {
+      losingOwnership = true;
+    },
+  };
+
+  add_task(function test_clipboard_owner() {
+    info(`Test clipboard owner for type ${aClipboardType} ${aAsync ? "async" : ""}`);
+
+    // Setup clipboard owner.
+    writeRandomStringToClipboard("text/plain", aClipboardType, clipboardOwner, aAsync);
+
+    // Test should not lose ownership.
+    clipboardTypes.forEach(function(otherType) {
+      losingOwnership = false;
+      if (aClipboardType != otherType && clipboard.isClipboardTypeSupported(otherType)) {
+        // Test setting clipboard data.
+        writeRandomStringToClipboard("text/plain", otherType);
+        ok(!losingOwnership, `Should not lose ownership while setting data to type ${otherType}`);
+
+        // Test async setting clipboard data.
+        writeRandomStringToClipboard("text/plain", otherType, null, true);
+        ok(!losingOwnership, `Should not lose ownership while async setting data to type ${otherType}`);
+      }
+    });
+
+    // Test whether should lose ownership.
+    losingOwnership = false;
+    writeRandomStringToClipboard("text/plain", aClipboardType, clipboardOwner);
+    ok(losingOwnership, `Should lose ownership while setting data to type ${aClipboardType}`);
+
+    losingOwnership = false;
+    writeRandomStringToClipboard("text/plain", aClipboardType, null, true);
+    ok(losingOwnership, `Should lose ownership while async setting data to type ${aClipboardType}`);
+
+    // Clean clipboard data.
+    cleanupAllClipboard();
+  });
+}
+
+/** Test for Bug 1812078 */
+clipboardTypes.forEach(function(testType) {
+  if (clipboard.isClipboardTypeSupported(testType)) {
+    // Test sync set clipboard data.
+    testClipboardOwner(testType, false);
+
+    // Test async set clipboard data.
+    testClipboardOwner(testType, true);
+  }
+});
+
+</script>
+</body>
+</html>
diff --git a/widget/tests/test_composition_text_querycontent.xhtml b/widget/tests/test_composition_text_querycontent.xhtml
new file mode 100644
index 0000000000..48b7af8100
--- /dev/null
+++ b/widget/tests/test_composition_text_querycontent.xhtml
@@ -0,0 +1,34 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Testing composition, text and query content events"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+// 3 assertions are: If setting selection with eSetSelection event whose range
+// is larger than the actual range, hits "Can only call this on frames that have
+// been reflowed:
+// '!(GetStateBits() & NS_FRAME_FIRST_REFLOW) || (GetParent()->GetStateBits() &
+// NS_FRAME_TOO_DEEP_IN_FRAME_TREE)'" in nsTextFrame.cpp.
+// Strangely, this doesn't occur with RDP on Windows.
+SimpleTest.expectAssertions(0, 3);
+SimpleTest.waitForExplicitFinish();
+window.openDialog("window_composition_text_querycontent.xhtml", "_blank", 
+                  "chrome,width=600,height=600,noopener", window);
+
+]]>
+</script>
+</window>
diff --git a/widget/tests/test_contextmenu_by_mouse_on_unix.html b/widget/tests/test_contextmenu_by_mouse_on_unix.html
new file mode 100644
index 0000000000..2b1f643dfc
--- /dev/null
+++ b/widget/tests/test_contextmenu_by_mouse_on_unix.html
@@ -0,0 +1,105 @@
+<!DOCTYPE html>
+<html>
+<head>
+<title>Test to fire contextmenu event by widget level</title>
+<script src="/tests/SimpleTest/EventUtils.js"></script>
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<script src="/tests/SimpleTest/SpecialPowers.js"></script>
+<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css">
+<style>
+#target {
+  width: 100px;
+  height: 100px;
+  background-color: blue;
+}
+</style>
+<script>
+"use strict";
+add_task(async function test_fire_contextmenu_by_mousedown() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["ui.context_menus.after_mouseup", false]],
+  });
+  await SimpleTest.promiseFocus();
+
+  // contextmenu event is fired by mouse down.
+  await process_contextmenu_event({ isMousedown: true, preventEvent: false });
+  // contextmenu event is fired by mouse down even if mouse handler calls preventDefault.
+  await process_contextmenu_event({ isMousedown: true, preventEvent: true });
+});
+
+add_task(async function test_fire_contextmenu_by_mouseup() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["ui.context_menus.after_mouseup", true]],
+  });
+  await SimpleTest.promiseFocus();
+
+  // contextmenu event is fired by mouse up.
+  await process_contextmenu_event({ isMousedown: false, preventEvent: false });
+  // contextmenu event is fired by mouse up even if mouse handler calls preventDefault.
+  await process_contextmenu_event({ isMousedown: false, preventEvent: true });
+});
+
+async function process_contextmenu_event({ isMousedown, preventEvent }) {
+  await SpecialPowers.contentTransformsReceived(window);
+
+  const target = document.getElementById("target");
+
+  let count = 0;
+
+  const promise = new Promise(resolve => {
+    target.addEventListener("mousedown", e => {
+      is(e.buttons, 2, "The right button down should be fired");
+      is(count++, 0, "The first event is mousedown");
+      if (isMousedown && preventEvent) {
+        e.preventDefault();
+      }
+    }, { once: true });
+
+    if (isMousedown) {
+      target.addEventListener("contextmenu", e => {
+        is(count++, 1, "The second event is contextmenu");
+        e.preventDefault();
+      }, { once: true });
+      target.addEventListener("mouseup", e => {
+        is(count++, 2, "The third event is mouseup");
+	resolve();
+      }, { once: true} );
+    } else {
+      target.addEventListener("mouseup", e => {
+        is(count++, 1, "The second event is mouseup");
+        if (preventEvent) {
+          e.preventDefault();
+        }
+      }, { once: true });
+      target.addEventListener("contextmenu", e => {
+        is(count++, 2, "The third event is contextmenu");
+        e.preventDefault();
+	resolve();
+      }, { once: true });
+    }
+  });
+
+  synthesizeNativeMouseEvent({
+    type: "mousedown",
+    target,
+    offsetX: 10,
+    offsetY: 10,
+    button: 2,
+  });
+
+  synthesizeNativeMouseEvent({
+    type: "mouseup",
+    target,
+    offsetX: 10,
+    offsetY: 10,
+    button: 2,
+  });
+
+  await promise;
+}
+</script>
+</head>
+<body>
+<div id="target"></div>
+</body>
+</html>
diff --git a/widget/tests/test_ime_state_in_contenteditable_on_readonly_change_in_parent.html b/widget/tests/test_ime_state_in_contenteditable_on_readonly_change_in_parent.html
new file mode 100644
index 0000000000..8d8662a8d8
--- /dev/null
+++ b/widget/tests/test_ime_state_in_contenteditable_on_readonly_change_in_parent.html
@@ -0,0 +1,72 @@
+<html>
+<head>
+  <title>Test for IME state of contenteditable on readonly state change</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="file_ime_state_test_helper.js"></script>
+  <script src="file_test_ime_state_in_contenteditable_on_readonly_change.js"></script>
+  <link rel="stylesheet" href="chrome://mochikit/content/tests/SimpleTest/test.css">
+<script>
+"use strict";
+
+/* import-globals-from file_ime_state_test_helper.js */
+/* import-globals-from file_test_ime_state_in_contenteditable_on_readonly_change.js */
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.waitForFocus(async () => {
+  const tipWrapper = new TIPWrapper(window);
+  const editingHost = document.querySelector("div[contenteditable]");
+  await (async function test_ime_state_in_contenteditable_on_readonly_change() {
+    const tester = new IMEStateInContentEditableOnReadonlyChangeTester();
+    tester.checkResultOfPreparation(await tester.prepareToRun(editingHost, editingHost), window, tipWrapper);
+    tester.checkResultOfMakingHTMLEditorReadonly(await tester.runToMakeHTMLEditorReadonly());
+    tester.checkResultOfMakingHTMLEditorEditable(await tester.runToMakeHTMLEditorEditable());
+    tester.checkResultOfRemovingContentEditableAttribute(await tester.runToRemoveContentEditableAttribute());
+    tester.clear();
+  })();
+
+  await (async function test_ime_state_in_button_in_contenteditable_on_readonly_change() {
+    const tester = new IMEStateInContentEditableOnReadonlyChangeTester();
+    const button = editingHost.querySelector("button");
+    tester.checkResultOfPreparation(await tester.prepareToRun(editingHost, button), window, tipWrapper);
+    tester.checkResultOfMakingHTMLEditorReadonly(await tester.runToMakeHTMLEditorReadonly());
+    tester.checkResultOfMakingHTMLEditorEditable(await tester.runToMakeHTMLEditorEditable());
+    tester.checkResultOfRemovingContentEditableAttribute(await tester.runToRemoveContentEditableAttribute());
+    tester.clear();
+  })();
+
+  await (async function test_ime_state_of_text_controls_in_contenteditable_on_readonly_change() {
+    const tester = new IMEStateOfTextControlInContentEditableOnReadonlyChangeTester();
+    for (let index = 0;
+         index < IMEStateOfTextControlInContentEditableOnReadonlyChangeTester.numberOfTextControlTypes;
+         index++) {
+      tester.checkResultOfPreparation(await tester.prepareToRun(index, editingHost), window, tipWrapper);
+      tester.checkResultOfMakingParentEditingHost(await tester.runToMakeParentEditingHost());
+      tester.checkResultOfMakingHTMLEditorReadonly(await tester.runToMakeHTMLEditorReadonly());
+      tester.checkResultOfMakingHTMLEditorEditable(await tester.runToMakeHTMLEditorEditable());
+      tester.checkResultOfMakingParentNonEditable(await tester.runToMakeParentNonEditingHost());
+      tester.clear();
+    }
+    editingHost.setAttribute("contenteditable", "");
+  })();
+
+  await (async function test_ime_state_outside_contenteditable_on_readonly_change() {
+    const tester = new IMEStateOutsideContentEditableOnReadonlyChangeTester();
+    for (let index = 0;
+         index < IMEStateOutsideContentEditableOnReadonlyChangeTester.numberOfFocusTargets;
+         index++) {
+      tester.checkResultOfPreparation(await tester.prepareToRun(index, editingHost), window, tipWrapper);
+      tester.checkResultOfMakingParentEditingHost(await tester.runToMakeParentEditingHost());
+      tester.checkResultOfMakingHTMLEditorReadonly(await tester.runToMakeHTMLEditorReadonly());
+      tester.checkResultOfMakingHTMLEditorEditable(await tester.runToMakeHTMLEditorEditable());
+      tester.checkResultOfMakingParentNonEditable(await tester.runToMakeParentNonEditingHost());
+      tester.clear();
+    }
+    editingHost.setAttribute("contenteditable", "");
+  })();
+
+  SimpleTest.finish();
+});
+</script>
+</head>
+<body><div contenteditable><br><button>button</button></div></body>
+</html>
diff --git a/widget/tests/test_ime_state_in_plugin_in_parent.html b/widget/tests/test_ime_state_in_plugin_in_parent.html
new file mode 100644
index 0000000000..9f3892ab88
--- /dev/null
+++ b/widget/tests/test_ime_state_in_plugin_in_parent.html
@@ -0,0 +1,92 @@
+<html>
+<head>
+  <title>Test for IME state on plugin</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="file_ime_state_test_helper.js"></script>
+  <link rel="stylesheet" href="chrome://mochikit/content/tests/SimpleTest/test.css">
+</head>
+<body>
+<input>
+<object type="application/x-test"></object>
+<script>
+"use strict";
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.waitForFocus(() => {
+  const tipWrapper = new TIPWrapper(window);
+  const plugin = document.querySelector("object");
+
+  // Plugins are not supported and their elements should not accept focus;
+  // therefore, IME should not enable when we play with it.
+
+  document.activeElement?.blur();
+  is(
+    window.windowUtils.IMEStatus,
+    Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    "IME enabled state should be disabled when no element has focus"
+  );
+  ok(
+    !tipWrapper.IMEHasFocus,
+    "IME should not have focus when no element has focus"
+  );
+
+  plugin.focus();
+  is(
+    window.windowUtils.IMEStatus,
+    Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    "IME enabled state should be disabled when an <object> for plugin has focus"
+  );
+  ok(
+    !tipWrapper.IMEHasFocus,
+    "IME should not have focus when an <object> for plugin has focus"
+  );
+
+  plugin.blur();
+  is(
+    window.windowUtils.IMEStatus,
+    Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    "IME enabled state should be disabled when an <object> for plugin gets blurred"
+  );
+  ok(
+    !tipWrapper.IMEHasFocus,
+    "IME should not have focus when an <object> for plugin gets blurred"
+  );
+
+  plugin.focus();
+  is(
+    window.windowUtils.IMEStatus,
+    Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    "IME enabled state should be disabled when an <object> for plugin gets focused again"
+  );
+  ok(
+    !tipWrapper.IMEHasFocus,
+    "IME should not have focus when an <object> for plugin gets focused again"
+  );
+
+  plugin.remove();
+  is(
+    window.windowUtils.IMEStatus,
+    Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+    "IME enabled state should be disabled when focused <object> for plugin is removed from the document"
+  );
+  ok(
+    !tipWrapper.IMEHasFocus,
+    "IME should not have focus when focused <object> for plugin is removed from the document"
+  );
+
+  document.querySelector("input").focus();
+  is(
+    window.windowUtils.IMEStatus,
+    Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+    "IME enabled state should be enabled after <input> gets focus"
+  );
+  ok(
+    tipWrapper.IMEHasFocus,
+    "IME should have focus after <input> gets focus"
+  );
+
+  SimpleTest.finish();
+});
+</script>
+</body>
+</html>
diff --git a/widget/tests/test_ime_state_in_text_control_on_reframe_in_parent.html b/widget/tests/test_ime_state_in_text_control_on_reframe_in_parent.html
new file mode 100644
index 0000000000..ab38806261
--- /dev/null
+++ b/widget/tests/test_ime_state_in_text_control_on_reframe_in_parent.html
@@ -0,0 +1,42 @@
+<html>
+<head>
+  <title>Test for IME state of contenteditable on readonly state change</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="file_ime_state_test_helper.js"></script>
+  <script src="file_test_ime_state_in_text_control_on_reframe.js"></script>
+  <link rel="stylesheet" href="chrome://mochikit/content/tests/SimpleTest/test.css">
+</head>
+<script>
+"use strict";
+
+/* import-globals-from file_ime_state_test_helper.js */
+/* import-globals-from file_test_ime_state_in_text_control_on_reframe.js */
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.waitForFocus(async () => {
+  const tipWrapper = new TIPWrapper(window);
+  const tester = new IMEStateInTextControlOnReframeTester();
+  for (let index = 0;
+        index < IMEStateInTextControlOnReframeTester.numberOfTextControlTypes;
+        index++) {
+    tipWrapper.clearFocusBlurNotifications();
+    const expectedData1 = await tester.prepareToRun(index, document);
+    tipWrapper.typeA();
+    await new Promise(resolve => requestAnimationFrame(
+      () => requestAnimationFrame(resolve)
+    )); // Flush IME content observer notifications.
+    tester.checkResultAfterTypingA(expectedData1, window, tipWrapper);
+
+    const expectedData2 = await tester.prepareToRun2(index, document);
+    tipWrapper.typeA();
+    await new Promise(resolve => requestAnimationFrame(
+      () => requestAnimationFrame(resolve)
+    )); // Flush IME content observer notifications.
+    tester.checkResultAfterTypingA2(expectedData2);
+  }
+
+  SimpleTest.finish();
+});
+</script>
+<body></body>
+</html>
diff --git a/widget/tests/test_ime_state_on_editable_state_change_in_parent.html b/widget/tests/test_ime_state_on_editable_state_change_in_parent.html
new file mode 100644
index 0000000000..a1b307a51f
--- /dev/null
+++ b/widget/tests/test_ime_state_on_editable_state_change_in_parent.html
@@ -0,0 +1,263 @@
+<!doctype html>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test for IME state management at changing editable state</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="file_ime_state_test_helper.js"></script>
+  <link rel="stylesheet" href="chrome://mochikit/content/tests/SimpleTest/test.css">
+</head>
+<body>
+<div></div>
+<script>
+"use strict";
+
+/* import-globals-from file_ime_state_test_helper.js */
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.waitForFocus(async () => {
+  const tipWrapper = new TIPWrapper(window);
+
+  function waitForIMEContentObserverSendingNotifications() {
+    return new Promise(
+      resolve => requestAnimationFrame(
+        () => requestAnimationFrame(resolve)
+      )
+    );
+  }
+
+  function resetIMEStateWithFocusMove() {
+    const input = document.createElement("input");
+    document.body.appendChild(input);
+    input.focus();
+    input.remove();
+    return waitForIMEContentObserverSendingNotifications();
+  }
+
+  await (async function test_setting_contenteditable_of_focused_div() {
+    const div = document.querySelector("div");
+    div.setAttribute("tabindex", "0");
+    div.focus();
+    is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      "test_setting_contenteditable_of_focused_div: IME should be disabled when non-editable <div> has focus"
+    );
+    div.setAttribute("contenteditable", "");
+    await waitForIMEContentObserverSendingNotifications();
+    // Sometimes, it's not enough waiting only 2 animation frames here to wait
+    // for IME focus, perhaps, it may be related to HTMLEditor initialization.
+    // Let's wait one more animation frame here.
+    if (!tipWrapper.IMEHasFocus) {
+      await new Promise(resolve => requestAnimationFrame(resolve));
+    }
+    is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+      "test_setting_contenteditable_of_focused_div: IME should be enabled when contenteditable of focused <div> is set"
+    );
+    ok(
+      tipWrapper.IMEHasFocus,
+      "test_setting_contenteditable_of_focused_div: IME should have focus when contenteditable of focused <div> is set"
+    )
+    div.removeAttribute("contenteditable");
+    await waitForIMEContentObserverSendingNotifications();
+    is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      "test_setting_contenteditable_of_focused_div: IME should be disabled when contenteditable of focused <div> is removed"
+    );
+    ok(
+      !tipWrapper.IMEHasFocus,
+      "test_setting_contenteditable_of_focused_div: IME should not have focus when contenteditable of focused <div> is removed"
+    );
+    div.removeAttribute("tabindex");
+  })();
+
+  await resetIMEStateWithFocusMove();
+
+  await (async function test_removing_contenteditable_of_non_last_editable_div() {
+    const div = document.querySelector("div");
+    div.setAttribute("tabindex", "0");
+    div.setAttribute("contenteditable", "");
+    const anotherEditableDiv = document.createElement("div");
+    anotherEditableDiv.setAttribute("contenteditable", "");
+    div.parentElement.appendChild(anotherEditableDiv);
+    div.focus();
+    await waitForIMEContentObserverSendingNotifications();
+    div.removeAttribute("contenteditable");
+    await waitForIMEContentObserverSendingNotifications();
+    is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      "test_removing_contenteditable_of_non_last_editable_div: IME should be disabled when contenteditable of focused <div> is removed"
+    );
+    ok(
+      !tipWrapper.IMEHasFocus,
+      "test_removing_contenteditable_of_non_last_editable_div: IME should not have focus when contenteditable of focused <div> is removed"
+    );
+    anotherEditableDiv.remove();
+    div.removeAttribute("tabindex");
+  })();
+
+  await resetIMEStateWithFocusMove();
+
+  await (async function test_setting_designMode() {
+    window.focus();
+    document.designMode = "on";
+    await waitForIMEContentObserverSendingNotifications();
+    is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+      'test_setting_designMode: IME should be enabled when designMode is set to "on"'
+    );
+    ok(
+      tipWrapper.IMEHasFocus,
+      'test_setting_designMode: IME should have focus when designMode is set to "on"'
+    );
+    document.designMode = "off";
+    await waitForIMEContentObserverSendingNotifications();
+    is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      'test_setting_designMode: IME should be disabled when designMode is set to "off"'
+    );
+    ok(
+      !tipWrapper.IMEHasFocus,
+      'test_setting_designMode: IME should not have focus when designMode is set to "off"'
+    );
+  })();
+
+  await resetIMEStateWithFocusMove();
+
+  async function test_setting_content_editable_of_body_when_shadow_DOM_has_focus(aMode) {
+    const div = document.querySelector("div");
+    const shadow = div.attachShadow({mode: aMode});
+    const divInShadow = document.createElement("div");
+    divInShadow.setAttribute("tabindex", "0");
+    shadow.appendChild(divInShadow);
+    divInShadow.focus();
+    await waitForIMEContentObserverSendingNotifications();
+    is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      `test_setting_content_editable_of_body_when_shadow_DOM_has_focus(${
+        aMode
+      }): IME should be disabled when non-editable <div> in a shadow DOM has focus`
+    );
+    document.body.setAttribute("contenteditable", "");
+    await waitForIMEContentObserverSendingNotifications();
+    // todo_is because of bug 1807597.  Gecko does not update focus when focused
+    // element becomes an editable child.  Therefore, cannot initialize
+    // HTMLEditor with the new editing host.
+    todo_is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+      `test_setting_content_editable_of_body_when_shadow_DOM_has_focus(${
+        aMode
+      }): IME should be enabled when the <body> becomes editable`
+    );
+    todo(
+      tipWrapper.IMEHasFocus,
+      `test_setting_content_editable_of_body_when_shadow_DOM_has_focus(${
+        aMode
+      }): IME should have focus when the <body> becomes editable`
+    );
+    document.body.removeAttribute("contenteditable");
+    await waitForIMEContentObserverSendingNotifications();
+    is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      `test_setting_content_editable_of_body_when_shadow_DOM_has_focus)${
+        aMode
+      }): IME should be disabled when the <body> becomes not editable`
+    );
+    ok(
+      !tipWrapper.IMEHasFocus,
+      `test_setting_content_editable_of_body_when_shadow_DOM_has_focus)${
+        aMode
+      }): IME should not have focus when the <body> becomes not editable`
+    );
+    div.remove();
+    document.body.appendChild(document.createElement("div"));
+  };
+
+  async function test_setting_designMode_when_shadow_DOM_has_focus(aMode) {
+    const div = document.querySelector("div");
+    const shadow = div.attachShadow({mode: aMode});
+    const divInShadow = document.createElement("div");
+    divInShadow.setAttribute("tabindex", "0");
+    shadow.appendChild(divInShadow);
+    divInShadow.focus();
+    await waitForIMEContentObserverSendingNotifications();
+    is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      `test_setting_designMode_when_shadow_DOM_has_focus(${
+        aMode
+      }): IME should be disabled when non-editable <div> in a shadow DOM has focus`
+    );
+    document.designMode = "on";
+    await waitForIMEContentObserverSendingNotifications();
+    is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      `test_setting_designMode_when_shadow_DOM_has_focus(${
+        aMode
+      }): IME should stay disabled when designMode is set`
+    );
+    ok(
+      !tipWrapper.IMEHasFocus,
+      `test_setting_designMode_when_shadow_DOM_has_focus(${
+        aMode
+      }): IME should not have focus when designMode is set`
+    );
+    divInShadow.setAttribute("contenteditable", "");
+    await waitForIMEContentObserverSendingNotifications();
+    // todo_is because of bug 1807597.  Gecko does not update focus when focused
+    // document is into the design mode.  Therefore, cannot initialize
+    // HTMLEditor with the document node properly.
+    todo_is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_ENABLED,
+      `test_setting_designMode_when_shadow_DOM_has_focus(${
+        aMode
+      }): IME should be enabled when focused <div> in a shadow DOM becomes editable`
+    );
+    todo(
+      tipWrapper.IMEHasFocus,
+      `test_setting_designMode_when_shadow_DOM_has_focus(${
+        aMode
+      }): IME should have focus when focused <div> in a shadow DOM becomes editable`
+    );
+    document.designMode = "off";
+    await waitForIMEContentObserverSendingNotifications();
+    is(
+      window.windowUtils.IMEStatus,
+      Ci.nsIDOMWindowUtils.IME_STATUS_DISABLED,
+      `test_setting_designMode_when_shadow_DOM_has_focus(${
+        aMode
+      }): IME should be disabled when designMode is unset`
+    );
+    ok(
+      !tipWrapper.IMEHasFocus,
+      `test_setting_designMode_when_shadow_DOM_has_focus(${
+        aMode
+      }): IME should not have focus when designMode is unset`
+    );
+    div.remove();
+    document.body.appendChild(document.createElement("div"));
+  }
+
+  for (const mode of ["open", "closed"]) {
+    await test_setting_content_editable_of_body_when_shadow_DOM_has_focus(mode);
+    await resetIMEStateWithFocusMove();
+    await test_setting_designMode_when_shadow_DOM_has_focus(mode);
+    await resetIMEStateWithFocusMove();
+  }
+
+  SimpleTest.finish();
+});
+</script>
+</body>
+</html>
diff --git a/widget/tests/test_ime_state_on_focus_move_in_parent.html b/widget/tests/test_ime_state_on_focus_move_in_parent.html
new file mode 100644
index 0000000000..fd74d61c7e
--- /dev/null
+++ b/widget/tests/test_ime_state_on_focus_move_in_parent.html
@@ -0,0 +1,88 @@
+<!doctype html>
+<html style="ime-mode: disabled;">
+<head>
+  <meta charset="utf-8">
+  <title>Test for IME state management on focus move in parent process</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"></script>
+  <script src="file_ime_state_test_helper.js"></script>
+  <script src="file_test_ime_state_on_focus_move.js"></script>
+  <link rel="stylesheet" href="chrome://mochikit/content/tests/SimpleTest/test.css">
+</head>
+<body style="ime-mode: disabled;">
+<div style="ime-mode: disabled;"></div>
+<script>
+"use strict";
+
+/* import-globals-from file_ime_state_test_helper.js */
+/* import-globals-from file_test_ime_state_on_focus_move.js */
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.waitForFocus(async () => {
+  const tipWrapper = new TIPWrapper(window);
+  ok(tipWrapper.isAvailable(), "TextInputProcessor should've been initialized");
+
+  const container = document.querySelector("div");
+  async function runIMEStateOnFocusMoveTests(aDescription) {
+    {
+      const runnerAndChecker = new IMEStateWhenNoActiveElementTester(aDescription);
+      const expectedData = await runnerAndChecker.run(document);
+      runnerAndChecker.check(expectedData);
+    }
+    for (let index = 0; index < IMEStateOnFocusMoveTester.numberOfTests; ++index) {
+      const runnerAndChecker = new IMEStateOnFocusMoveTester(aDescription, index);
+      const expectedData = await runnerAndChecker.prepareToRun(container);
+      runnerAndChecker.prepareToCheck(expectedData, tipWrapper);
+      await runnerAndChecker.run();
+      runnerAndChecker.check(expectedData);
+      if (runnerAndChecker.canTestOpenCloseState(expectedData)) {
+        for (const defaultOpenState of [false, true]) {
+          const expectedOpenStateData =
+            await runnerAndChecker.prepareToRunOpenCloseTest(container);
+          runnerAndChecker.prepareToCheckOpenCloseTest(
+            defaultOpenState,
+            expectedOpenStateData
+          );
+          await runnerAndChecker.runOpenCloseTest();
+          runnerAndChecker.checkOpenCloseTest(expectedOpenStateData);
+        }
+      }
+      runnerAndChecker.destroy();
+    }
+  }
+
+  // test for normal contents.
+  await runIMEStateOnFocusMoveTests("in non-editable container");
+
+  // test for contentEditable="true"
+  container.setAttribute("contenteditable", "true");
+  await runIMEStateOnFocusMoveTests("in div[contenteditable]");
+
+  // test for contentEditable="false"
+  container.setAttribute("contenteditable", "false");
+  await runIMEStateOnFocusMoveTests('in div[contenteditable="false"]');
+
+  // test for removing contentEditable
+  container.setAttribute("contenteditable", "true");
+  container.focus();
+  await new Promise(resolve =>
+    requestAnimationFrame(
+      () => requestAnimationFrame(resolve)
+    )
+  );
+  container.removeAttribute("contenteditable");
+  await runIMEStateOnFocusMoveTests("after removing contenteditable from the container");
+
+  // test designMode
+  document.designMode = "on";
+  await runIMEStateOnFocusMoveTests('in designMode="on"');
+  document.designMode = "off";
+  await runIMEStateOnFocusMoveTests('in designMode="off"');
+
+  tipWrapper.destroy();
+
+  SimpleTest.finish();
+});
+</script>
+</body>
+</html>
diff --git a/widget/tests/test_ime_state_on_input_type_change_in_parent.html b/widget/tests/test_ime_state_on_input_type_change_in_parent.html
new file mode 100644
index 0000000000..2644c31e3f
--- /dev/null
+++ b/widget/tests/test_ime_state_on_input_type_change_in_parent.html
@@ -0,0 +1,39 @@
+<html>
+<head>
+  <title>Test for IME state on input type change</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="file_ime_state_test_helper.js"></script>
+  <script src="file_test_ime_state_on_input_type_change.js"></script>
+  <link rel="stylesheet" href="chrome://mochikit/content/tests/SimpleTest/test.css">
+<script>
+"use strict";
+
+/* import-globals-from file_ime_state_test_helper.js */
+/* import-globals-from file_test_ime_state_on_input_type_change.js */
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.expectAssertions(6); // Hit in IMEStateManager::UpdateIMEState
+SimpleTest.waitForFocus(async () => {
+  const tipWrapper = new TIPWrapper(window);
+  for (let srcIndex = 0; srcIndex < IMEStateOnInputTypeChangeTester.numberOfTests; srcIndex++) {
+    const tester = new IMEStateOnInputTypeChangeTester(srcIndex);
+    for (let destIndex = 0; destIndex < IMEStateOnInputTypeChangeTester.numberOfTests; destIndex++) {
+      const expectedResultBefore = await tester.prepareToRun(destIndex, window, document.body);
+      if (expectedResultBefore === false) {
+        continue;
+      }
+      tester.checkBeforeRun(expectedResultBefore, tipWrapper);
+      const expectedResult = await tester.run();
+      tester.checkResult(expectedResultBefore, expectedResult);
+      tipWrapper.clearFocusBlurNotifications();
+      tester.clear();
+    }
+  }
+
+  SimpleTest.finish();
+});
+</script>
+</head>
+<body>
+</body>
+</html>
diff --git a/widget/tests/test_ime_state_on_readonly_change_in_parent.html b/widget/tests/test_ime_state_on_readonly_change_in_parent.html
new file mode 100644
index 0000000000..0557856542
--- /dev/null
+++ b/widget/tests/test_ime_state_on_readonly_change_in_parent.html
@@ -0,0 +1,31 @@
+<html>
+<head>
+  <title>Test for IME state on readonly state change</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="file_ime_state_test_helper.js"></script>
+  <script src="file_test_ime_state_on_readonly_change.js"></script>
+  <link rel="stylesheet" href="chrome://mochikit/content/tests/SimpleTest/test.css">
+<script>
+"use strict";
+
+/* import-globals-from file_ime_state_test_helper.js */
+/* import-globals-from file_test_ime_state_on_readonly_change.js */
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.waitForFocus(async () => {
+  const tipWrapper = new TIPWrapper(window);
+  const tester = new IMEStateOnReadonlyChangeTester();
+  for (let i = 0; i < IMEStateOnReadonlyChangeTester.numberOfTextControlTypes; i++) {
+    tester.checkBeforeRun(await tester.prepareToRun(i, window, document.body), tipWrapper);
+    tester.checkResultOfMakingTextControlReadonly(await tester.runToMakeTextControlReadonly());
+    tester.checkResultOfMakingTextControlEditable(await tester.runToMakeTextControlEditable());
+    tipWrapper.clearFocusBlurNotifications();
+    tester.clear();
+  }
+  SimpleTest.finish();
+});
+</script>
+</head>
+<body>
+</body>
+</html>
diff --git a/widget/tests/test_ime_state_others_in_parent.html b/widget/tests/test_ime_state_others_in_parent.html
new file mode 100644
index 0000000000..e6ae0ab272
--- /dev/null
+++ b/widget/tests/test_ime_state_others_in_parent.html
@@ -0,0 +1,153 @@
+<html>
+<head>
+  <title>Test for IME state controlling in some special cases</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"></script>
+  <script src="file_ime_state_test_helper.js"></script>
+  <link rel="stylesheet" type="text/css"
+          href="chrome://mochikit/content/tests/SimpleTest/test.css" />
+</head>
+<body>
+<div id="display"></div>
+<div id="content" style="display: none"></div>
+<pre id="test"></pre>
+<script>
+SimpleTest.waitForExplicitFinish();
+
+var gUtils = window.windowUtils;
+var gFM = Services.focus;
+
+function runEditorFlagChangeTests() {
+  var description = "runEditorFlagChangeTests: ";
+
+  var container = document.getElementById("display");
+
+  // Reset selection from previous tests.
+  window.getSelection().collapse(container, 0);
+
+  // the editor has focus directly.
+  container.setAttribute("contenteditable", "true");
+  container.focus();
+
+  is(gFM.focusedElement, container,
+     description + "The editor doesn't get focus");
+  is(gUtils.IMEStatus, gUtils.IME_STATUS_ENABLED,
+     description + "IME isn't enabled on HTML editor");
+  const kIMEStateChangeFlags = Ci.nsIEditor.eEditorReadonlyMask;
+  const kFlagsNotAllowedWithHTMLEditor =
+    Ci.nsIEditor.eEditorPasswordMask |
+    Ci.nsIEditor.eEditorSingleLineMask;
+  var editor = window.docShell.editor;
+  var flags = editor.flags;
+
+  // input characters
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3078\u3093\u3057\u3093",
+        "clauses":
+        [
+          { "length": 4, "attr": COMPOSITION_ATTR_RAW_CLAUSE },
+        ],
+      },
+      "caret": { "start": 4, "length": 0 },
+    });
+
+  editor.flags &= ~kIMEStateChangeFlags;
+  ok(editor.composing,
+     description + "#1 IME composition was committed unexpectedly");
+  is(gUtils.IMEStatus, gUtils.IME_STATUS_ENABLED,
+     description + "#1 IME isn't enabled on HTML editor");
+
+  editor.flags |=
+      ~(kIMEStateChangeFlags | kFlagsNotAllowedWithHTMLEditor);
+  ok(editor.composing,
+     description + "#2 IME composition was committed unexpectedly");
+  is(gUtils.IMEStatus, gUtils.IME_STATUS_ENABLED,
+     description + "#2 IME isn't enabled on HTML editor");
+
+  editor.flags = flags;
+  ok(editor.composing,
+     description + "#3 IME composition was committed unexpectedly");
+  is(gUtils.IMEStatus, gUtils.IME_STATUS_ENABLED,
+     description + "#3 IME isn't enabled on HTML editor");
+
+  // cancel the composition
+  synthesizeComposition({ type: "compositioncommit", data: "" });
+
+  container.removeAttribute("contenteditable");
+}
+
+function runEditableSubframeTests() {
+  window.open("window_imestate_iframes.html", "_blank",
+              "width=600,height=600");
+}
+
+function runTestPasswordFieldOnDialog() {
+  if (document.activeElement) {
+    document.activeElement.blur();
+  }
+
+  var dialog;
+
+  function WindowObserver() {
+    Services.obs.addObserver(this, "domwindowopened");
+  }
+
+  WindowObserver.prototype = {
+    QueryInterface: ChromeUtils.generateQI(["nsIObserver"]),
+
+    observe(subject, topic, data) {
+      if (topic === "domwindowopened") {
+        ok(true, "dialog window is created");
+        dialog = subject;
+        dialog.addEventListener("load", onPasswordDialogLoad);
+      }
+    },
+  };
+
+  var observer = new WindowObserver();
+  var arg1 = {}, arg2 = {};
+  Services.prompt.promptPassword(window, "title", "text", arg1, "msg", arg2);
+
+  ok(true, "password dialog was closed");
+
+  Services.obs.removeObserver(observer, "domwindowopened");
+
+  var passwordField;
+
+  function onPasswordDialogLoad() {
+    ok(true, "onPasswordDialogLoad is called");
+    dialog.removeEventListener("load", onPasswordDialogLoad);
+    passwordField = dialog.document.getElementById("password1Textbox");
+    passwordField.addEventListener("focus", onPasswordFieldFocus);
+  }
+
+  function onPasswordFieldFocus() {
+    ok(true, "onPasswordFieldFocus is called");
+    passwordField.removeEventListener("focus", onPasswordFieldFocus);
+    var utils = dialog.windowUtils;
+    is(utils.IMEStatus, utils.IME_STATUS_PASSWORD,
+       "IME isn't disabled on a password field of password dialog");
+    synthesizeKey("VK_ESCAPE", { }, dialog);
+  }
+}
+
+SimpleTest.waitForFocus(async () => {
+  // test whether the IME state and composition are not changed unexpectedly
+  runEditorFlagChangeTests();
+
+  // test password field on dialog
+  // XXX temporary disable against failure
+  // runTestPasswordFieldOnDialog();
+
+  // This will call onFinish(), so, this test must be the last.
+  // TODO: Make this test run with remote content too.
+  runEditableSubframeTests();
+});
+
+function onFinish() {
+  SimpleTest.finish();
+}
+</script>
+</body>
+</html>
diff --git a/widget/tests/test_input_events_on_deactive_window.xhtml b/widget/tests/test_input_events_on_deactive_window.xhtml
new file mode 100644
index 0000000000..d54699f76c
--- /dev/null
+++ b/widget/tests/test_input_events_on_deactive_window.xhtml
@@ -0,0 +1,233 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Testing composition, text and query content events"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="content" style="display: none">
+</div>
+<p id="display">
+  <textarea id="textarea"></textarea>
+</p>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.waitForFocus(runTests, window);
+
+var textarea = document.getElementById("textarea");
+var otherWindow;
+var timer;
+
+function runTests()
+{
+  textarea.focus();
+  is(Services.focus.focusedElement, textarea, "we're deactive");
+  if (Services.focus.focusedElement != textarea) {
+    SimpleTest.finish();
+    return;
+  }
+
+  otherWindow =
+    window.browsingContext.topChromeWindow.open(
+        "./file_input_events_on_deactive_window.html", "_blank",
+        "chrome,width=100,height=100");
+  ok(otherWindow, "failed to open other window");
+  if (!otherWindow) {
+    SimpleTest.finish();
+    return;
+  }
+
+  SimpleTest.waitForFocus(startTests, otherWindow);
+  otherWindow.focus();
+}
+
+function startTests()
+{
+  clearTimeout(timer);
+  isnot(Services.focus.focusedWindow, window, "we're not deactive");
+  if (Services.focus.focusedWindow == window) {
+    otherWindow.close();
+    SimpleTest.finish();
+    return;
+  }
+
+  var keydownHandled, keypressHandled, keyupHandled, compositionstartHandled,
+      compositionendHandled, compositionupdateHandled, inputHandled;
+
+  function clear()
+  {
+    keydownHandled = false;
+    keypressHandled = false;
+    keyupHandled = false;
+    compositionstartHandled = false;
+    compositionendHandled = false;
+    compositionupdateHandled = false;
+    inputHandled = false;
+  }
+
+  function onEvent(aEvent)
+  {
+    if (aEvent.type == "keydown") {
+      keydownHandled = true;
+    } else if (aEvent.type == "keypress") {
+      keypressHandled = true;
+    } else if (aEvent.type == "keyup") {
+      keyupHandled = true;
+    } else if (aEvent.type == "compositionstart") {
+      compositionstartHandled = true;
+    } else if (aEvent.type == "compositionend") {
+      compositionendHandled = true;
+    } else if (aEvent.type == "compositionupdate") {
+      compositionupdateHandled = true;
+    } else if (aEvent.type == "input") {
+      inputHandled = true;
+    } else {
+      ok(false, "handled unknown event: " + aEvent.type);
+    }
+  }
+
+  textarea.addEventListener("keydown", onEvent);
+  textarea.addEventListener("keypress", onEvent);
+  textarea.addEventListener("keyup", onEvent);
+  textarea.addEventListener("compositionstart", onEvent);
+  textarea.addEventListener("compositionend", onEvent);
+  textarea.addEventListener("compositionupdate", onEvent);
+  textarea.addEventListener("input", onEvent);
+
+  startTestsInternal();
+
+  function startTestsInternal()
+  {
+    // key events
+    function checkKeyEvents(aKeydown, aKeypress, aKeyup, aInput, aDescription)
+    {
+      is(keydownHandled, aKeydown,
+         "keydown event is (not) handled: " + aDescription);
+      is(keypressHandled, aKeypress,
+         "keypress event is (not) handled: " + aDescription);
+      is(keyupHandled, aKeyup,
+         "keyup event is (not) handled: " + aDescription);
+      is(inputHandled, aInput,
+         "input event is (not) handled: " + aDescription);
+    }
+
+    function checkCompositionEvents(aStart, aEnd, aUpdate, aInput, aDescription)
+    {
+      is(compositionstartHandled, aStart,
+         "compositionstart event is (not) handled: " + aDescription);
+      is(compositionendHandled, aEnd,
+         "compositionend event is (not) handled: " + aDescription);
+      is(compositionupdateHandled, aUpdate,
+         "compositionupdate event is (not) handled: " + aDescription);
+      is(inputHandled, aInput,
+         "input event is (not) handled: " + aDescription);
+    }
+
+    clear();
+    synthesizeKey("a", {type: "keydown"});
+    checkKeyEvents(true, true, false, true, "a keydown and a keypress");
+    is(textarea.value, "a", "textarea value isn't 'a'");
+    clear();
+    synthesizeKey("a", {type: "keyup"});
+    checkKeyEvents(false, false, true, false, "a keyup");
+    clear();
+    synthesizeKey("KEY_Backspace");
+    checkKeyEvents(true, true, true, true, "KEY_Backspace key events");
+    is(textarea.value, "", "textarea value isn't empty");
+
+    // IME events
+    clear();
+    // input first character
+    synthesizeCompositionChange(
+      { "composition":
+        { "string": "\u3089",
+          "clauses":
+          [
+            { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+          ]
+        },
+        "caret": { "start": 1, "length": 0 }
+      });
+    checkCompositionEvents(true, false, true, true, "starting to compose");
+    var queryText = synthesizeQueryTextContent(0, 100);
+    ok(queryText, "query text event result is null");
+    if (!queryText) {
+      return;
+    }
+    ok(queryText.succeeded, "query text event failed");
+    if (!queryText.succeeded) {
+      return;
+    }
+    is(queryText.text, "\u3089", "composing text is incorrect");
+    var querySelectedText = synthesizeQuerySelectedText();
+    ok(querySelectedText, "query selected text event result is null");
+    if (!querySelectedText) {
+      return;
+    }
+    ok(querySelectedText.succeeded, "query selected text event failed");
+    if (!querySelectedText.succeeded) {
+      return;
+    }
+    is(querySelectedText.offset, 1,
+       "query selected text event returns wrong offset");
+    is(querySelectedText.text, "",
+       "query selected text event returns wrong selected text");
+    clear();
+    // commit composition
+    synthesizeComposition({ type: "compositioncommitasis" });
+    checkCompositionEvents(false, true, false, true, "commit composition as is");
+    queryText = synthesizeQueryTextContent(0, 100);
+    ok(queryText, "query text event result is null after commit");
+    if (!queryText) {
+      return;
+    }
+    ok(queryText.succeeded, "query text event failed after commit");
+    if (!queryText.succeeded) {
+      return;
+    }
+    is(queryText.text, "\u3089", "composing text is incorrect after commit");
+    querySelectedText = synthesizeQuerySelectedText();
+    ok(querySelectedText,
+       "query selected text event result is null after commit");
+    if (!querySelectedText) {
+      return;
+    }
+    ok(querySelectedText.succeeded,
+       "query selected text event failed after commit");
+    if (!querySelectedText.succeeded) {
+      return;
+    }
+    is(querySelectedText.offset, 1,
+       "query selected text event returns wrong offset after commit");
+    is(querySelectedText.text, "",
+       "query selected text event returns wrong selected text after commit");
+    clear();
+  }
+
+  textarea.removeEventListener("keydown", onEvent);
+  textarea.removeEventListener("keypress", onEvent);
+  textarea.removeEventListener("keyup", onEvent);
+  textarea.removeEventListener("compositionstart", onEvent);
+  textarea.removeEventListener("compositionupdate", onEvent);
+  textarea.removeEventListener("compositionend", onEvent);
+  textarea.removeEventListener("input", onEvent);
+
+  otherWindow.close();
+
+  SimpleTest.finish();
+}
+
+
+]]>
+</script>
+</window>
diff --git a/widget/tests/test_key_event_counts.xhtml b/widget/tests/test_key_event_counts.xhtml
new file mode 100644
index 0000000000..6eda6a52fb
--- /dev/null
+++ b/widget/tests/test_key_event_counts.xhtml
@@ -0,0 +1,90 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css" type="text/css"?>
+
+<!-- We've had issues on Mac OS X where native key events either don't get processed
+     or they get processed twice. This test tests some of those scenarios. -->
+
+<window id="window1" title="Test Key Event Counts" onload="runTest()"
+  xmlns:html="http://www.w3.org/1999/xhtml"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"/>
+  <script src="chrome://mochikit/content/tests/SimpleTest/NativeKeyCodes.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <p id="display"></p>
+    <div id="content" style="display: none"></div>
+    <pre id="test"></pre>
+  </body>
+
+  <script type="application/javascript"><![CDATA[
+    var gKeyPressEventCount = 0;
+    var gKeyDownEventCount = 0;
+
+    function onKeyDown(e)
+    {
+      gKeyDownEventCount++;
+    }
+
+    function onKeyPress(e)
+    {
+      gKeyPressEventCount++;
+      e.preventDefault();
+    }
+
+    function* testBody()
+    {
+      window.addEventListener("keydown", onKeyDown);
+      window.addEventListener("keypress", onKeyPress);
+
+      // Test ctrl-tab
+      gKeyDownEventCount = 0;
+      gKeyPressEventCount = 0;
+      yield synthesizeNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_Tab, {ctrlKey:1}, "\t", "\t", continueTest);
+      is(gKeyDownEventCount, 1);
+      is(gKeyPressEventCount, 0, "ctrl-tab should be consumed by tabbox of tabbrowser at keydown");
+
+      // Test cmd+shift+a
+      gKeyDownEventCount = 0;
+      gKeyPressEventCount = 0;
+      yield synthesizeNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_A, {metaKey:1, shiftKey:1}, "a", "A", continueTest);
+      is(gKeyDownEventCount, 1);
+      is(gKeyPressEventCount, 1);
+
+      // Test cmd-;
+      gKeyDownEventCount = 0;
+      gKeyPressEventCount = 0;
+      yield synthesizeNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_Semicolon, {metaKey:1}, ";", ";", continueTest);
+      is(gKeyDownEventCount, 1);
+      is(gKeyPressEventCount, 1);
+
+      window.removeEventListener("keydown", onKeyDown);
+      window.removeEventListener("keypress", onKeyPress);
+    }
+
+    var gTestContinuation = null;
+
+    function continueTest()
+    {
+      if (!gTestContinuation) {
+        gTestContinuation = testBody();
+      }
+      var ret = gTestContinuation.next();
+      if (ret.done) {
+        SimpleTest.finish();
+      } else {
+        is(ret.value, true, "Key synthesized successfully");
+      }
+    }
+
+    function runTest()
+    {
+      SimpleTest.waitForExplicitFinish();
+      continueTest();
+    }
+  ]]></script>
+
+</window>
diff --git a/widget/tests/test_keycodes.xhtml b/widget/tests/test_keycodes.xhtml
new file mode 100644
index 0000000000..aea6aaae98
--- /dev/null
+++ b/widget/tests/test_keycodes.xhtml
@@ -0,0 +1,5647 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Key event tests"
+  onload="runTest()"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+  <script src="chrome://mochikit/content/tests/SimpleTest/NativeKeyCodes.js" />
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js" />
+
+<commandset>
+  <command id="expectedCommand" oncommand="this.activeCount++" disabled="true"/>
+  <command id="unexpectedCommand" oncommand="this.activeCount++" disabled="true"/>
+  <command id="expectedReservedCommand" oncommand="this.activeCount++" reserved="true" disabled="true"/>
+</commandset>
+<keyset>
+  <key id="unshiftedKey" key=";" modifiers="accel" command="unexpectedCommand"/>
+  <key id="shiftedKey" key=":" modifiers="accel" command="unexpectedCommand"/>
+  <key id="commandOptionF" key='f' modifiers="accel,alt" command="unexpectedCommand"/>
+  <key id="question" key='?' modifiers="accel" command="unexpectedCommand"/>
+  <key id="unshiftedX" key="x" modifiers="accel" command="unexpectedCommand"/>
+  <key id="shiftedX" key="X" modifiers="accel,shift" command="unexpectedCommand"/>
+  <key id="ctrlAltA" key="a" modifiers="accel,alt" command="unexpectedCommand"/>
+  <key id="ctrlAltShiftA" key="A" modifiers="accel,alt,shift" command="unexpectedCommand"/>
+  <key id="unshiftedPlus" key="+" modifiers="accel" command="unexpectedCommand"/>
+  <key id="reservedUnshiftedKey" key="'" modifiers="accel" command="unexpectedCommand"/>
+  <key id="reservedShiftedKey" key='"' modifiers="accel" command="unexpectedCommand"/>
+</keyset>
+
+<browser id="browser" type="content" src="data:text/html;charset=utf-8,&lt;button id='content_button'&gt;button&lt;/button&gt;" width="200" height="32"/>
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<p id="display">
+  <!-- for some reason, if we don't have 'accesskey' here, adding it dynamically later
+       doesn't work! -->
+  <button id="button" accesskey="z">Hello</button>
+  <input type="text" id="textbox" value=""/>
+</p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+const IS_MAC = navigator.platform.indexOf("Mac") == 0;
+const IS_WIN = navigator.platform.indexOf("Win") == 0;
+const OS_VERSION =
+  IS_WIN  ? parseFloat(Services.sysinfo.getProperty("version")) : 0;
+const WIN8 = 6.2; // Can remove once bug 1594270 is closed
+
+function isModifierKeyEvent(aEvent)
+{
+  switch (aEvent.key) {
+    case "Alt":
+    case "AltGraph":
+    case "CapsLock":
+    case "Control":
+    case "Fn":
+    case "FnLock":
+    case "Hyper":
+    case "Meta":
+    case "NumLock":
+    case "ScrollLock":
+    case "Shift":
+    case "Super":
+    case "Symbol":
+    case "SymbolLock":
+      return true;
+    default:
+      return false;
+  }
+}
+
+/**
+ * Firefox infobar UI can have access keys which conflict with this test. Really
+ * stupid workaround until we can move this test into its own chrome window.
+ */
+function clearInfobars()
+{
+  var browser = window.top.docShell.chromeEventHandler;
+  var chromeWin = browser.ownerGlobal;
+  var nb = chromeWin.gBrowser.getNotificationBox(browser);
+  for (let n of nb.allNotifications) {
+    nb.removeNotification(n, true);
+  }
+}
+
+function eventToString(aEvent)
+{
+  var name = aEvent.layout.name + " keyCode=" +
+    aEvent.keyCode + " (0x" + aEvent.keyCode.toString(16).toUpperCase() +
+      ") chars='" + aEvent.chars + "'";
+  if (typeof aEvent.unmodifiedChars === "string") {
+    name += " unmodifiedChars='" + aEvent.unmodifiedChars + "'";
+  }
+  if (aEvent.modifiers.capsLockKey) {
+    name += " [CapsLock]";
+  }
+  if (aEvent.modifiers.shiftKey) {
+    name += " [Shift]";
+  }
+  if (aEvent.modifiers.shiftRightKey) {
+    name += " [Right Shift]";
+  }
+  if (aEvent.modifiers.ctrlKey) {
+    name += " [Ctrl]";
+  }
+  if (aEvent.modifiers.ctrlRightKey) {
+    name += " [Right Ctrl]";
+  }
+  if (aEvent.modifiers.altKey) {
+    name += " [Alt]";
+  }
+  if (aEvent.modifiers.altGrKey) {
+    name += " [AltGr]";
+  }
+  if (aEvent.modifiers.altRightKey) {
+    name += " [Right Alt]";
+  }
+  if (aEvent.modifiers.metaKey) {
+    name += ` [${IS_MAC ? "Command" : "Win"}]`;
+  }
+  if (aEvent.modifiers.metaRightKey) {
+    name += ` [Right ${IS_MAC ? "Command" : "Win"}]`;
+  }
+
+  return name;  
+}
+
+function getPhase(aDOMEvent)
+{
+  switch (aDOMEvent.eventPhase) {
+    case aDOMEvent.None:
+      return "none";
+    case aDOMEvent.CAPTURING_PHASE:
+      return "capture";
+    case aDOMEvent.AT_TARGET:
+      return "target";
+    case aDOMEvent.BUBBLING_PHASE:
+      return "bubble";
+    default:
+      return "";
+   }
+}
+
+function eventTargetToString(aEventTarget)
+{
+  if (aEventTarget.navigator) {
+    return "window";
+  }
+  switch (aEventTarget.nodeType) {
+    case Node.ELEMENT_NODE:
+      return "element (" + aEventTarget.tagName + ")";
+    case Node.DOCUMENT_NODE:
+      return "document";
+    default:
+      return "";
+  }
+}
+
+function synthesizeKey(aEvent, aFocusElementId, aCallback)
+{
+  if (aFocusElementId.startsWith("content_")) {
+    var browser = document.getElementById("browser");
+    browser.contentDocument.getElementById(aFocusElementId).focus();
+  } else {
+    document.getElementById(aFocusElementId).focus();
+  }
+
+  return synthesizeNativeKey(aEvent.layout, aEvent.keyCode,
+                             aEvent.modifiers,
+                             aEvent.chars, aEvent.unmodifiedChars,
+                             aCallback);
+}
+
+// Test the charcodes and modifiers being delivered to keypress handlers and
+// also keydown/keyup events too.
+function* runKeyEventTests()
+{
+  var currentTestName;
+  var eventList, keyDownFlags, keyUpFlags, testingEvent, expectedDOMKeyCode;
+  const kShiftFlag    = 0x1;
+  const kCtrlFlag     = 0x2;
+  const kAltFlag      = 0x4;
+  const kMetaFlag     = 0x8;
+  const kNumLockFlag  = 0x10;
+  const kCapsLockFlag = 0x20;
+  const kAltGraphFlag = 0x40;
+
+  function onKeyEvent(e)
+  {
+    /* eslint-disable-next-line no-shadow */
+    function removeFlag(e, aFlag)
+    {
+      if (e.type == "keydown") {
+        let oldValue = keyDownFlags;
+        keyDownFlags &= ~aFlag;
+        return oldValue != keyDownFlags;
+      } else if (e.type == "keyup") {
+        let oldValue = keyUpFlags;
+        keyUpFlags &= ~aFlag;
+        return oldValue != keyUpFlags;
+      }
+      return false;
+    }
+
+    /* eslint-disable-next-line no-shadow, complexity */
+    function isStateChangingModifierKeyEvent(e)
+    {
+      var flags = 0;
+      if (e.type == "keydown") {
+        flags = keyDownFlags ^ keyUpFlags;
+      } else if (e.type == "keyup") {
+        flags = keyUpFlags;
+      }
+      switch (e.key) {
+        case "Shift":
+          is(e.ctrlKey, (flags & kCtrlFlag) != 0,
+             currentTestName + ", Ctrl of Shift " + e.type + " event mismatch");
+          is(e.metaKey, (flags & kMetaFlag) != 0,
+             currentTestName + ", Command of Shift " + e.type + " event mismatch");
+          is(e.altKey, (flags & kAltFlag) != 0,
+             currentTestName + ", Alt of Shift " + e.type + " event mismatch");
+          is(e.shiftKey, e.type == "keydown",
+             currentTestName + ", Shift of Shift " + e.type + " event mismatch");
+          // AltGr on Windows is always pressed after and released before Shift key operation.
+          is(e.getModifierState("AltGraph"), (IS_MAC && e.altKey),
+             currentTestName + ", AltGraph of Shift " + e.type + " event mismatch");
+          return (testingEvent.modifiers.shiftKey || testingEvent.modifiers.shiftRightKey) &&
+                 removeFlag(e, kShiftFlag) && expectedDOMKeyCode != e.keyCode;
+        case "Control":
+          is(e.ctrlKey, e.type == "keydown",
+             currentTestName + ", Ctrl of Ctrl " + e.type + " event mismatch");
+          is(e.metaKey, (flags & kMetaFlag) != 0,
+             currentTestName + ", Command of Ctrl " + e.type + " event mismatch");
+          // When AltGr key is released on Windows, ControlLeft keyup event
+          // is followed by AltRight keyup event.  However, altKey should be
+          // false in such case.
+          is(e.altKey, (flags & kAltFlag) != 0 && !(IS_WIN && !!testingEvent.modifiers.altGrKey),
+             currentTestName + ", Alt of Ctrl " + e.type + " event mismatch");
+          is(e.shiftKey, (flags & kShiftFlag) != 0,
+             currentTestName + ", Shift of Ctrl " + e.type + " event mismatch");
+          is(e.getModifierState("AltGraph"),
+             (IS_WIN && !!testingEvent.modifiers.altGrKey && e.type == "keyup") || (IS_MAC && e.altKey),
+             currentTestName + ", AltGraph of Ctrl " + e.type + " event mismatch");
+          return (testingEvent.modifiers.ctrlKey || testingEvent.modifiers.ctrlRightKey ||
+                  (IS_WIN && !!testingEvent.modifiers.altGrKey)) &&
+                 removeFlag(e, kCtrlFlag) && expectedDOMKeyCode != e.keyCode;
+        case "Alt":
+          is(e.ctrlKey, (flags & kCtrlFlag) != 0 && !(IS_WIN && !!testingEvent.modifiers.altGrKey),
+             currentTestName + ", Ctrl of Alt " + e.type + " event mismatch");
+          is(e.metaKey, (flags & kMetaFlag) != 0,
+             currentTestName + ", Command of Alt " + e.type + " event mismatch");
+          is(e.altKey, e.type == "keydown" && !(IS_WIN && !!testingEvent.modifiers.altGrKey),
+             currentTestName + ", Alt of Alt " + e.type + " event mismatch");
+          is(e.shiftKey, (flags & kShiftFlag) != 0,
+             currentTestName + ", Shift of Alt " + e.type + " event mismatch");
+          is(e.getModifierState("AltGraph"),
+             e.type == "keydown" && ((IS_WIN && !!testingEvent.modifiers.altGrKey) || (IS_MAC && e.altKey)),
+             currentTestName + ", AltGraph of Alt " + e.type + " event mismatch");
+          return (testingEvent.modifiers.altKey || testingEvent.modifiers.altRightKey ||
+                  (IS_WIN && !!testingEvent.modifiers.altGrKey)) &&
+                 removeFlag(e, kAltFlag) && expectedDOMKeyCode != e.keyCode;
+        case "AltGraph":
+          // On Windows, AltGraph events are fired only when AltRight key is
+          // pressed when active keyboard layout maps AltGraph to AltRight.
+          // Note that AltGraph is represented with pressing both Control key
+          // and Alt key.  Therefore, when AltGraph keyboard event is fired,
+          // both ctrlKey and altKey are always false on Windows.
+          is(e.ctrlKey, (flags & kCtrlFlag) != 0 && !IS_WIN,
+             currentTestName + ", Ctrl of AltGraph " + e.type + " event mismatch");
+          is(e.metaKey, (flags & kMetaFlag) != 0,
+             currentTestName + ", Command of AltGraph " + e.type + " event mismatch");
+          is(e.altKey, (flags & kAltFlag) != 0 && !IS_WIN,
+             currentTestName + ", Alt of AltGraph " + e.type + " event mismatch");
+          is(e.shiftKey, (flags & kShiftFlag) != 0,
+             currentTestName + ", Shift of Ctrl " + e.type + " event mismatch");
+          is(e.getModifierState("AltGraph"), e.type === "keydown",
+             currentTestName + ", AltGraph of AltGraph " + e.type + " event mismatch");
+          return IS_WIN && testingEvent.modifiers.altGrKey &&
+                 removeFlag(e, kAltGraphFlag) && expectedDOMKeyCode != e.keyCode;
+        case "Meta":
+          is(e.ctrlKey, (flags & kCtrlFlag) != 0,
+             currentTestName + ", Ctrl of Command " + e.type + " event mismatch");
+          is(e.metaKey, e.type == "keydown",
+             currentTestName + ", Command of Command " + e.type + " event mismatch");
+          is(e.altKey, (flags & kAltFlag) != 0,
+             currentTestName + ", Alt of Command " + e.type + " event mismatch");
+          is(e.shiftKey, (flags & kShiftFlag) != 0,
+             currentTestName + ", Shift of Command " + e.type + " event mismatch");
+          is(e.getModifierState("AltGraph"),
+             (IS_WIN && (flags & kAltGraphFlag) != 0) || (IS_MAC && e.altKey),
+             currentTestName + ", AltGraph of Meta " + e.type + " event mismatch");
+          return (testingEvent.modifiers.metaKey || testingEvent.modifiers.metaRightKey) &&
+                 removeFlag(e, kMetaFlag) && expectedDOMKeyCode != e.keyCode;
+        case "NumLock":
+          is(e.ctrlKey, (flags & kCtrlFlag) != 0,
+             currentTestName + ", Ctrl of NumLock " + e.type + " event mismatch");
+          is(e.metaKey, (flags & kMetaFlag) != 0,
+             currentTestName + ", Command of NumLock " + e.type + " event mismatch");
+          is(e.altKey, (flags & kAltFlag) != 0,
+             currentTestName + ", Alt of NumLock " + e.type + " event mismatch");
+          is(e.shiftKey, (flags & kShiftFlag) != 0,
+             currentTestName + ", Shift of NumLock " + e.type + " event mismatch");
+          is(e.getModifierState("AltGraph"), false,
+             currentTestName + ", AltGraph of NumLock " + e.type + " event mismatch");
+          // AltGr on Windows is always pressed after and released before NumLock key operation.
+          return (testingEvent.modifiers.numLockKey || testingEvent.modifiers.numericKeyPadKey) &&
+                 removeFlag(e, kNumLockFlag) && expectedDOMKeyCode != e.keyCode;
+        case "CapsLock":
+          is(e.ctrlKey, (flags & kCtrlFlag) != 0,
+             currentTestName + ", Ctrl of CapsLock " + e.type + " event mismatch");
+          is(e.metaKey, (flags & kMetaFlag) != 0,
+             currentTestName + ", Command of CapsLock " + e.type + " event mismatch");
+          is(e.altKey, (flags & kAltFlag) != 0,
+             currentTestName + ", Alt of CapsLock " + e.type + " event mismatch");
+          is(e.shiftKey, (flags & kShiftFlag) != 0,
+             currentTestName + ", Shift of CapsLock " + e.type + " event mismatch");
+          // AltGr on Windows is always pressed after and released before CapsLock key operation.
+          is(e.getModifierState("AltGraph"), false,
+             currentTestName + ", AltGraph of CapsLock " + e.type + " event mismatch");
+          return testingEvent.modifiers.capsLockKey &&
+                 removeFlag(e, kCapsLockFlag) && expectedDOMKeyCode != e.keyCode;
+      }
+      return false;
+    }
+
+    // Ignore the state changing key events which is fired by the testing event.
+    if (!isStateChangingModifierKeyEvent(e))
+      eventList.push(e);
+  }
+
+  function consumer(aEvent)
+  {
+    aEvent.preventDefault();
+  }
+
+  const SHOULD_DELIVER_KEYDOWN          = 0x1;
+  const SHOULD_DELIVER_KEYPRESS         = 0x2;
+  const SHOULD_DELIVER_KEYUP            = 0x4;
+  const SHOULD_DELIVER_ALL              = SHOULD_DELIVER_KEYDOWN |
+                                          SHOULD_DELIVER_KEYPRESS |
+                                          SHOULD_DELIVER_KEYUP;
+  const SHOULD_DELIVER_KEYDOWN_KEYUP    = SHOULD_DELIVER_KEYDOWN |
+                                          SHOULD_DELIVER_KEYUP;
+  const SHOULD_DELIVER_KEYDOWN_KEYPRESS = SHOULD_DELIVER_KEYDOWN |
+                                          SHOULD_DELIVER_KEYPRESS;
+
+  // The first parameter is the complete input event. The second parameter is
+  // what to test against. The third parameter is which key events should be
+  // delived for the event.
+  // @param aExpectedKeyValues     Can be string or array of string.
+  //                               If all keyboard events have same key value,
+  //                               specify it as string.  Otherwise, specify
+  //                               each key value in array.
+  function testKey(aEvent, aExpectedKeyValues, aExpectedCodeValue,
+                   aExpectedGeckoKeyCode, aExpectGeckoChar,
+                   aShouldDelivedEvent, aExpectLocation)
+  {
+    ok(aExpectedGeckoKeyCode != undefined, "keycode is undefined");
+    eventList = [];
+
+    // The modifier key events which are fired for state changing are har to
+    // test. We should ignore them for now.
+    keyDownFlags = keyUpFlags = 0;
+    if (!IS_MAC) {
+      // On Mac, nsChildView doesn't generate modifier keydown/keyup events for
+      // state changing for synthesizeNativeKeyEvent.
+      if (aEvent.modifiers.shiftKey || aEvent.modifiers.shiftRightKey) {
+        keyDownFlags |= kShiftFlag;
+      }
+      if (aEvent.modifiers.ctrlKey || aEvent.modifiers.ctrlRightKey ||
+          (IS_WIN && aEvent.modifiers.altGrKey)) {
+        keyDownFlags |= kCtrlFlag;
+      }
+      if (aEvent.modifiers.altKey || aEvent.modifiers.altRightKey) {
+        keyDownFlags |= kAltFlag;
+      }
+      if (aEvent.modifiers.altGrKey) {
+        keyDownFlags |= kAltGraphFlag;
+      }
+      if (aEvent.modifiers.metaKey || aEvent.modifiers.metaRightKey) {
+        keyDownFlags |= kMetaFlag;
+      }
+      if (aEvent.modifiers.numLockKey || aEvent.modifiers.numericKeyPadKey) {
+        keyDownFlags |= kNumLockFlag;
+      }
+      if (aEvent.modifiers.capsLockKey) {
+        keyDownFlags |= kCapsLockFlag;
+      }
+      keyUpFlags = keyDownFlags;
+    }
+
+    testingEvent = aEvent;
+    expectedDOMKeyCode = aExpectedGeckoKeyCode;
+
+    currentTestName = eventToString(aEvent);
+    ok(true, "Starting: " + currentTestName);
+
+    // eslint-disable-next-line complexity
+    return synthesizeKey(aEvent, "button", function() {
+
+      var expectEventTypeList = [];
+      if (aShouldDelivedEvent & SHOULD_DELIVER_KEYDOWN)
+        expectEventTypeList.push("keydown");
+      if (aShouldDelivedEvent & SHOULD_DELIVER_KEYPRESS) {
+        expectEventTypeList.push("keypress");
+        for (let i = 1; i < aExpectGeckoChar.length; i++) {
+          expectEventTypeList.push("keypress");
+        }
+      }
+      if (aShouldDelivedEvent & SHOULD_DELIVER_KEYUP)
+        expectEventTypeList.push("keyup");
+      is(eventList.length, expectEventTypeList.length,
+         currentTestName + ", wrong number of key events");
+
+      var longerLength = Math.max(eventList.length, expectEventTypeList.length);
+      var keypressCount = 0;
+      for (let i = 0; i < longerLength; i++) {
+        var firedEventType = i < eventList.length ? eventList[i].type : "";
+        var expectEventType = i < expectEventTypeList.length ? expectEventTypeList[i] : "";
+        if (firedEventType != "") {
+          is(firedEventType, expectEventType,
+             currentTestName + ", " + expectEventType + " should be fired");
+        } else {
+          is(firedEventType, expectEventType,
+             currentTestName + ", a needed event is not fired");
+        }
+
+        if (firedEventType != "") {
+          var expectedKeyValue =
+            // eslint-disable-next-line no-nested-ternary
+            typeof aExpectedKeyValues === "string" ? aExpectedKeyValues :
+                     i < aExpectedKeyValues.length ? aExpectedKeyValues[i] :
+                                                     undefined;
+
+          var e = eventList[i];
+          switch (e.key) {
+            case "Shift":
+            case "Control":
+            case "Alt":
+            case "AltGraph":
+            case "Meta":
+            case "CapsLock":
+            case "NumLock":
+              // XXX To check modifier state of modifiers, we need to check
+              //     e.type since modifier key may change modifier state.
+              //     However, doing it makes the following check more
+              //     complicated.  So, we ignore the modifier state of
+              //     modifier keydown/keyup events for now.
+              break;
+            default:
+              is(e.shiftKey, !!(aEvent.modifiers.shiftKey || aEvent.modifiers.shiftRightKey),
+                 currentTestName + ", Shift of " + e.type + " of " + e.code + " mismatch");
+              is(e.metaKey, !!(aEvent.modifiers.metaKey || aEvent.modifiers.metaRightKey),
+                 currentTestName + ", Meta of " + e.type + " of " + e.code + " mismatch");
+              var isControlPressed = !!(aEvent.modifiers.ctrlKey || aEvent.modifiers.ctrlRightKey);
+              var isAltPressed = !!(aEvent.modifiers.altKey || aEvent.modifiers.altRightKey);
+              var isAltGraphExpected =
+                !!aEvent.modifiers.altGrKey ||
+                (IS_WIN && aEvent.layout.hasAltGrOnWin &&
+                 isControlPressed && isAltPressed &&
+                 (aEvent.isInputtingCharacters || expectedKeyValue == "Dead")) ||
+                (IS_MAC && isAltPressed);
+              var isControlExpected = !(IS_WIN && isAltGraphExpected) && isControlPressed;
+              var isAltExpected = !(IS_WIN && isAltGraphExpected) && isAltPressed;
+              if (e.type == "keypress" && aEvent.isInputtingCharacters) {
+                isControlExpected = false;
+                isAltExpected = false;
+              }
+              is(e.ctrlKey, isControlExpected,
+                 currentTestName + ", Ctrl of " + e.type + " of " + e.code + " mismatch");
+              is(e.altKey, isAltExpected,
+                 currentTestName + ", Alt of " + e.type + " of " + e.code + " mismatch");
+              is(e.getModifierState("AltGraph"), isAltGraphExpected,
+                 currentTestName + ", AltGraph of " + e.type + " of " + e.code + " mismatch");
+              break;
+          }
+
+          is(e.key, expectedKeyValue, currentTestName + ", wrong key value");
+          is(e.code, aExpectedCodeValue, currentTestName + ", wrong code value");
+
+          if (aExpectGeckoChar.length && e.type == "keypress") {
+            is(e.charCode, aExpectGeckoChar.charCodeAt(keypressCount++),
+               currentTestName + ", charcode");
+            if (aExpectedGeckoKeyCode >= 0) {
+              if (aExpectGeckoChar) {
+                is(e.keyCode, 0,
+                   currentTestName + ", wrong keycode");
+              } else {
+                is(e.keyCode, aExpectedGeckoKeyCode,
+                   currentTestName + ", wrong keycode");
+              }
+            }
+          } else {
+            is(e.charCode, 0,
+               currentTestName + ", no charcode");
+            if (aExpectedGeckoKeyCode >= 0) {
+              is(e.keyCode, aExpectedGeckoKeyCode,
+                 currentTestName + ", wrong keycode");
+            }
+          }
+          is(e.location, aExpectLocation,
+             currentTestName + ", wrong location");
+        }
+      }
+
+      continueTest();
+    });
+  }
+
+  // These tests have to be per-plaform.
+  document.addEventListener("keydown",  onKeyEvent);
+  document.addEventListener("keypress", onKeyEvent);
+  document.addEventListener("keyup",    onKeyEvent);
+  // Prevent almost all shortcut key handlers.
+  SpecialPowers.addSystemEventListener(document, "keypress", consumer, true);
+
+  function cleanup()
+  {
+    document.removeEventListener("keydown",  onKeyEvent);
+    document.removeEventListener("keypress", onKeyEvent);
+    document.removeEventListener("keyup",    onKeyEvent);
+    SpecialPowers.removeSystemEventListener(document, "keypress", consumer, true);
+  }
+
+  function* testKeysOnMac()
+  {
+    // On Mac, you can produce event records for any desired keyboard input
+    // by running with NSPR_LOG_MODULES=TextInputHandlerWidgets:5 and typing
+    // into the browser.  We will dump the key event fields to the console
+    // (Find TextInputHandler::HandleKeyDownEvent or
+    // TextInputHandler::HandleKeyUpEvent in the log). Use the International system
+    // preferences widget to enable other keyboard layouts and select them from the
+    // input menu to see what keyboard events they generate.
+    // Note that it's possible to send bogus key events here, e.g.
+    // {keyCode:0, chars:"z", unmodifiedChars:"P"} --- sendNativeKeyEvent
+    // makes no attempt to verify that the keyCode matches the characters. So only
+    // test key event records that you saw Cocoa send.
+
+    // Command keys
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{metaKey:1}, chars:"a", unmodifiedChars:"a"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // Shift-cmd gives us the shifted character
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{metaKey:1, shiftKey:1}, chars:"a", unmodifiedChars:"A"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // Ctrl-cmd gives us the unshifted character
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{metaKey:1, ctrlKey:1}, chars:"\u0001", unmodifiedChars:"a"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // Alt-cmd gives us the shifted character
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{metaKey:1, altKey:1}, chars:"\u00e5", unmodifiedChars:"a"},
+                  "\u00e5", "KeyA", KeyboardEvent.DOM_VK_A, "\u00e5", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{metaKey:1, altKey:1, shiftKey:1}, chars:"\u00c5", unmodifiedChars:"a"},
+                  "\u00c5", "KeyA", KeyboardEvent.DOM_VK_A, "\u00c5", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Greek ctrl keys produce Latin charcodes
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1}, chars:"\u0001", unmodifiedChars:"\u03b1"},
+                  "\u03b1", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0001", unmodifiedChars:"\u0391"},
+                  "\u0391", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Greek command keys
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{metaKey:1}, chars:"a", unmodifiedChars:"\u03b1"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // Shift-cmd gives us the shifted character
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{metaKey:1, shiftKey:1}, chars:"a", unmodifiedChars:"\u0391"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Ctrl-cmd gives us the unshifted character
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{metaKey:1, ctrlKey:1}, chars:"\u0001", unmodifiedChars:"\u03b1"},
+                  "\u03b1", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // Alt-cmd gives us the shifted character
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{metaKey:1, altKey:1}, chars:"\u00a8", unmodifiedChars:"\u03b1"},
+                  "\u00a8", "KeyA", KeyboardEvent.DOM_VK_A, "\u00a8", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{metaKey:1, altKey:1, shiftKey:1}, chars:"\u00b9", unmodifiedChars:"\u0391"},
+                  "\u00b9", "KeyA", KeyboardEvent.DOM_VK_A, "\u00b9", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // German
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:MAC_VK_ANSI_A,
+                   modifiers: {}, chars:"a", unmodifiedChars:"a"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers: {}, chars:"\u00fc", unmodifiedChars:"\u00fc"},
+                  "\u00fc", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "\u00fc", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers: {}, chars:"\u00df", unmodifiedChars:"\u00df"},
+                  "\u00df", "Minus", KeyboardEvent.DOM_VK_QUESTION_MARK, "\u00df", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{shiftKey:1}, chars:"?", unmodifiedChars:"?"},
+                  "?", "Minus", KeyboardEvent.DOM_VK_QUESTION_MARK, "?", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // Note that Shift+SS is '?' but Cmd+Shift+SS is '/' on German layout.
+    // Therefore, when Cmd key is pressed, the SS key's keycode is changed.
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{metaKey:1}, chars:"\u00df", unmodifiedChars:"\u00df"},
+                  "\u00df", "Minus", KeyboardEvent.DOM_VK_SLASH, "\u00df", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{metaKey:1, shiftKey:1}, chars:"/", unmodifiedChars:"?"},
+                  "/", "Minus", KeyboardEvent.DOM_VK_SLASH, "?", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Caps Lock key event
+    // XXX keyup event of Caps Lock key is not fired.
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_CapsLock,
+                   modifiers:{capsLockKey:1}, chars:"", unmodifiedChars:""},
+                  "CapsLock", "CapsLock", KeyboardEvent.DOM_VK_CAPS_LOCK, "", SHOULD_DELIVER_KEYDOWN, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_CapsLock,
+                   modifiers:{capsLockKey:0}, chars:"", unmodifiedChars:""},
+                  "CapsLock", "CapsLock", KeyboardEvent.DOM_VK_CAPS_LOCK, "", SHOULD_DELIVER_KEYDOWN, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Shift/RightShift key event
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Shift,
+                   modifiers:{shiftKey:1}, chars:"", unmodifiedChars:""},
+                  "Shift", "ShiftLeft", KeyboardEvent.DOM_VK_SHIFT, "", SHOULD_DELIVER_KEYDOWN, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Shift,
+                   modifiers:{shiftKey:0}, chars:"", unmodifiedChars:""},
+                  "Shift", "ShiftLeft", KeyboardEvent.DOM_VK_SHIFT, "", SHOULD_DELIVER_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_RightShift,
+                   modifiers:{shiftRightKey:1}, chars:"", unmodifiedChars:""},
+                  "Shift", "ShiftRight", KeyboardEvent.DOM_VK_SHIFT, "", SHOULD_DELIVER_KEYDOWN, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_RightShift,
+                   modifiers:{shiftRightKey:0}, chars:"", unmodifiedChars:""},
+                  "Shift", "ShiftRight", KeyboardEvent.DOM_VK_SHIFT, "", SHOULD_DELIVER_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+
+    // Control/RightControl key event
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Control,
+                   modifiers:{ctrlKey:1}, chars:"", unmodifiedChars:""},
+                  "Control", "ControlLeft", KeyboardEvent.DOM_VK_CONTROL, "", SHOULD_DELIVER_KEYDOWN, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Control,
+                   modifiers:{ctrlKey:0}, chars:"", unmodifiedChars:""},
+                  "Control", "ControlLeft", KeyboardEvent.DOM_VK_CONTROL, "", SHOULD_DELIVER_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_RightControl,
+                   modifiers:{ctrlRightKey:1}, chars:"", unmodifiedChars:""},
+                  "Control", "ControlRight", KeyboardEvent.DOM_VK_CONTROL, "", SHOULD_DELIVER_KEYDOWN, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_RightControl,
+                   modifiers:{ctrlRightKey:0}, chars:"", unmodifiedChars:""},
+                  "Control", "ControlRight", KeyboardEvent.DOM_VK_CONTROL, "", SHOULD_DELIVER_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+
+    // Option/RightOption key event
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Option,
+                   modifiers:{altKey:1}, chars:"", unmodifiedChars:""},
+                  "Alt", "AltLeft", KeyboardEvent.DOM_VK_ALT, "", SHOULD_DELIVER_KEYDOWN, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Option,
+                   modifiers:{altKey:0}, chars:"", unmodifiedChars:""},
+                  "Alt", "AltLeft", KeyboardEvent.DOM_VK_ALT, "", SHOULD_DELIVER_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_RightOption,
+                   modifiers:{altRightKey:1}, chars:"", unmodifiedChars:""},
+                  "Alt", "AltRight", KeyboardEvent.DOM_VK_ALT, "", SHOULD_DELIVER_KEYDOWN, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_RightOption,
+                   modifiers:{altRightKey:0}, chars:"", unmodifiedChars:""},
+                  "Alt", "AltRight", KeyboardEvent.DOM_VK_ALT, "", SHOULD_DELIVER_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+
+    // Command/RightCommand key event
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Command,
+                   modifiers:{metaKey:1}, chars:"", unmodifiedChars:""},
+                  "Meta", "MetaLeft", KeyboardEvent.DOM_VK_META, "", SHOULD_DELIVER_KEYDOWN, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Command,
+                   modifiers:{metaKey:0}, chars:"", unmodifiedChars:""},
+                  "Meta", "MetaLeft", KeyboardEvent.DOM_VK_META, "", SHOULD_DELIVER_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_RightCommand,
+                   modifiers:{metaRightKey:1}, chars:"", unmodifiedChars:""},
+                  "Meta", "MetaRight", KeyboardEvent.DOM_VK_META, "", SHOULD_DELIVER_KEYDOWN, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_RightCommand,
+                   modifiers:{metaRightKey:0}, chars:"", unmodifiedChars:""},
+                  "Meta", "MetaRight", KeyboardEvent.DOM_VK_META, "", SHOULD_DELIVER_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+
+    // all keys on keyboard (keyCode test)
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Tab,
+                   modifiers: {}, chars:"\t", unmodifiedChars:"\t"},
+                  "Tab", "Tab", KeyboardEvent.DOM_VK_TAB, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadClear,
+                   modifiers: {}, chars:"\uF739", unmodifiedChars:"\uF739"},
+                  "Clear", "NumLock", KeyboardEvent.DOM_VK_CLEAR, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Return,
+                   modifiers: {}, chars:"\u000D", unmodifiedChars:"\u000D"},
+                  "Enter", "Enter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_PC_Pause,
+                   modifiers: {}, chars:"\uF712", unmodifiedChars:"\uF712"},
+                  "F15", "F15", KeyboardEvent.DOM_VK_PAUSE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Escape,
+                   modifiers: {}, chars:"\u001B", unmodifiedChars:"\u001B"},
+                  "Escape", "Escape", KeyboardEvent.DOM_VK_ESCAPE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Space,
+                   modifiers: {}, chars:" ", unmodifiedChars:" "},
+                  " ", "Space", KeyboardEvent.DOM_VK_SPACE, " ", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_PageUp,
+                   modifiers: {}, chars:"\uF72C", unmodifiedChars:"\uF72C"},
+                  "PageUp", "PageUp", KeyboardEvent.DOM_VK_PAGE_UP, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_PageDown,
+                   modifiers: {}, chars:"\uF72D", unmodifiedChars:"\uF72D"},
+                  "PageDown", "PageDown", KeyboardEvent.DOM_VK_PAGE_DOWN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_End,
+                   modifiers: {}, chars:"\uF72B", unmodifiedChars:"\uF72B"},
+                  "End", "End", KeyboardEvent.DOM_VK_END, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_Home,
+                   modifiers: {}, chars:"\uF729", unmodifiedChars:"\uF729"},
+                  "Home", "Home", KeyboardEvent.DOM_VK_HOME, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_LeftArrow,
+                   modifiers: {}, chars:"\uF702", unmodifiedChars:"\uF702"},
+                  "ArrowLeft", "ArrowLeft", KeyboardEvent.DOM_VK_LEFT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_UpArrow,
+                   modifiers: {}, chars:"\uF700", unmodifiedChars:"\uF700"},
+                  "ArrowUp", "ArrowUp", KeyboardEvent.DOM_VK_UP, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_RightArrow,
+                   modifiers: {}, chars:"\uF703", unmodifiedChars:"\uF703"},
+                  "ArrowRight", "ArrowRight", KeyboardEvent.DOM_VK_RIGHT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_DownArrow,
+                   modifiers: {}, chars:"\uF701", unmodifiedChars:"\uF701"},
+                  "ArrowDown", "ArrowDown", KeyboardEvent.DOM_VK_DOWN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_PC_PrintScreen,
+                   modifiers: {}, chars:"\uF710", unmodifiedChars:"\uF710"},
+                  "F13", "F13", KeyboardEvent.DOM_VK_PRINTSCREEN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_PC_Delete,
+                   modifiers: {}, chars:"\uF728", unmodifiedChars:"\uF728"},
+                  "Delete", "Delete", KeyboardEvent.DOM_VK_DELETE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_PC_ScrollLock,
+                   modifiers: {}, chars:"\uF711", unmodifiedChars:"\uF711"},
+                  "F14", "F14", KeyboardEvent.DOM_VK_SCROLL_LOCK, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_PC_ContextMenu,
+                   modifiers: {}, chars:"\u0010", unmodifiedChars:"\u0010"},
+                  "ContextMenu", "ContextMenu", KeyboardEvent.DOM_VK_CONTEXT_MENU, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F1,
+                   modifiers:{fnKey:1}, chars:"\uF704", unmodifiedChars:"\uF704"},
+                  "F1", "F1", KeyboardEvent.DOM_VK_F1, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F2,
+                   modifiers:{fnKey:1}, chars:"\uF705", unmodifiedChars:"\uF705"},
+                  "F2", "F2", KeyboardEvent.DOM_VK_F2, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F3,
+                   modifiers:{fnKey:1}, chars:"\uF706", unmodifiedChars:"\uF706"},
+                  "F3", "F3", KeyboardEvent.DOM_VK_F3, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F4,
+                   modifiers:{fnKey:1}, chars:"\uF707", unmodifiedChars:"\uF707"},
+                  "F4", "F4", KeyboardEvent.DOM_VK_F4, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F5,
+                   modifiers:{fnKey:1}, chars:"\uF708", unmodifiedChars:"\uF708"},
+                  "F5", "F5", KeyboardEvent.DOM_VK_F5, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F6,
+                   modifiers:{fnKey:1}, chars:"\uF709", unmodifiedChars:"\uF709"},
+                  "F6", "F6", KeyboardEvent.DOM_VK_F6, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F7,
+                   modifiers:{fnKey:1}, chars:"\uF70A", unmodifiedChars:"\uF70A"},
+                  "F7", "F7", KeyboardEvent.DOM_VK_F7, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F8,
+                   modifiers:{fnKey:1}, chars:"\uF70B", unmodifiedChars:"\uF70B"},
+                  "F8", "F8", KeyboardEvent.DOM_VK_F8, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F9,
+                   modifiers:{fnKey:1}, chars:"\uF70C", unmodifiedChars:"\uF70C"},
+                  "F9", "F9", KeyboardEvent.DOM_VK_F9, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F10,
+                   modifiers:{fnKey:1}, chars:"\uF70D", unmodifiedChars:"\uF70D"},
+                  "F10", "F10", KeyboardEvent.DOM_VK_F10, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F11,
+                   modifiers:{fnKey:1}, chars:"\uF70E", unmodifiedChars:"\uF70E"},
+                  "F11", "F11", KeyboardEvent.DOM_VK_F11, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F12,
+                   modifiers:{fnKey:1}, chars:"\uF70F", unmodifiedChars:"\uF70F"},
+                  "F12", "F12", KeyboardEvent.DOM_VK_F12, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F16,
+                   modifiers:{fnKey:1}, chars:"\uF713", unmodifiedChars:"\uF713"},
+                  "F16", "F16", KeyboardEvent.DOM_VK_F16, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F17,
+                   modifiers:{fnKey:1}, chars:"\uF714", unmodifiedChars:"\uF714"},
+                  "F17", "F17", KeyboardEvent.DOM_VK_F17, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F18,
+                   modifiers:{fnKey:1}, chars:"\uF715", unmodifiedChars:"\uF715"},
+                  "F18", "F18", KeyboardEvent.DOM_VK_F18, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_F19,
+                   modifiers:{fnKey:1}, chars:"\uF716", unmodifiedChars:"\uF716"},
+                  "F19", "F19", KeyboardEvent.DOM_VK_F19, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // US
+    // Alphabet
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers: {}, chars:"a", unmodifiedChars:"a"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{shiftKey:1}, chars:"A", unmodifiedChars:"A"},
+                  "A", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1}, chars:"\u0001", unmodifiedChars:"a"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0001", unmodifiedChars:"A"},
+                  "A", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, capsLockKey:1}, chars:"\u0001", unmodifiedChars:"a"},
+                  "A", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, shiftKey:1, capsLockKey:1}, chars:"\u0001", unmodifiedChars:"A"},
+                  "A", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{altKey:1}, chars:"\u00E5", unmodifiedChars:"a"},
+                  "\u00E5", "KeyA", KeyboardEvent.DOM_VK_A, "\u00E5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00C5", unmodifiedChars:"A"},
+                  "\u00C5", "KeyA", KeyboardEvent.DOM_VK_A, "\u00C5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0001", unmodifiedChars:"a"},
+                  "\u00E5", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0001", unmodifiedChars:"A"},
+                  "\u00C5", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{metaKey:1}, chars:"a", unmodifiedChars:"a"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{}, chars:"b", unmodifiedChars:"b"},
+                  "b", "KeyB", KeyboardEvent.DOM_VK_B, "b", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{shiftKey:1}, chars:"B", unmodifiedChars:"B"},
+                  "B", "KeyB", KeyboardEvent.DOM_VK_B, "B", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{ctrlKey:1}, chars:"\u0002", unmodifiedChars:"b"},
+                  "b", "KeyB", KeyboardEvent.DOM_VK_B, "b", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0002", unmodifiedChars:"B"},
+                  "B", "KeyB", KeyboardEvent.DOM_VK_B, "B", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{altKey:1}, chars:"\u222B", unmodifiedChars:"b"},
+                  "\u222B", "KeyB", KeyboardEvent.DOM_VK_B, "\u222B", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u0131", unmodifiedChars:"B"},
+                  "\u0131", "KeyB", KeyboardEvent.DOM_VK_B, "\u0131", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0002", unmodifiedChars:"b"},
+                  "\u222B", "KeyB", KeyboardEvent.DOM_VK_B, "b", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0002", unmodifiedChars:"B"},
+                  "\u0131", "KeyB", KeyboardEvent.DOM_VK_B, "B", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{metaKey:1}, chars:"b", unmodifiedChars:"b"},
+                  "b", "KeyB", KeyboardEvent.DOM_VK_B, "b", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_C,
+                   modifiers:{}, chars:"c", unmodifiedChars:"c"},
+                  "c", "KeyC", KeyboardEvent.DOM_VK_C, "c", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_C,
+                   modifiers:{shiftKey:1}, chars:"C", unmodifiedChars:"C"},
+                  "C", "KeyC", KeyboardEvent.DOM_VK_C, "C", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_C,
+                   modifiers:{ctrlKey:1}, chars:"\u0003", unmodifiedChars:"c"},
+                  "c", "KeyC", KeyboardEvent.DOM_VK_C, "c", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_C,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0003", unmodifiedChars:"C"},
+                  "C", "KeyC", KeyboardEvent.DOM_VK_C, "C", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_C,
+                   modifiers:{altKey:1}, chars:"\u00E7", unmodifiedChars:"c"},
+                  "\u00E7", "KeyC", KeyboardEvent.DOM_VK_C, "\u00E7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_C,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00C7", unmodifiedChars:"C"},
+                  "\u00C7", "KeyC", KeyboardEvent.DOM_VK_C, "\u00C7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_C,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0003", unmodifiedChars:"c"},
+                  "\u00E7", "KeyC", KeyboardEvent.DOM_VK_C, "c", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_C,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0003", unmodifiedChars:"C"},
+                  "\u00C7", "KeyC", KeyboardEvent.DOM_VK_C, "C", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_C,
+                   modifiers:{metaKey:1}, chars:"c", unmodifiedChars:"c"},
+                  "c", "KeyC", KeyboardEvent.DOM_VK_C, "c", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{}, chars:"d", unmodifiedChars:"d"},
+                  "d", "KeyD", KeyboardEvent.DOM_VK_D, "d", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{shiftKey:1}, chars:"D", unmodifiedChars:"D"},
+                  "D", "KeyD", KeyboardEvent.DOM_VK_D, "D", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{ctrlKey:1}, chars:"\u0004", unmodifiedChars:"d"},
+                  "d", "KeyD", KeyboardEvent.DOM_VK_D, "d", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0004", unmodifiedChars:"D"},
+                  "D", "KeyD", KeyboardEvent.DOM_VK_D, "D", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{altKey:1}, chars:"\u2202", unmodifiedChars:"d"},
+                  "\u2202", "KeyD", KeyboardEvent.DOM_VK_D, "\u2202", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00CE", unmodifiedChars:"D"},
+                  "\u00CE", "KeyD", KeyboardEvent.DOM_VK_D, "\u00CE", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0004", unmodifiedChars:"d"},
+                  "\u2202", "KeyD", KeyboardEvent.DOM_VK_D, "d", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0004", unmodifiedChars:"D"},
+                  "\u00CE", "KeyD", KeyboardEvent.DOM_VK_D, "D", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{metaKey:1}, chars:"d", unmodifiedChars:"d"},
+                  "d", "KeyD", KeyboardEvent.DOM_VK_D, "d", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_E,
+                   modifiers:{}, chars:"e", unmodifiedChars:"e"},
+                  "e", "KeyE", KeyboardEvent.DOM_VK_E, "e", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_E,
+                   modifiers:{shiftKey:1}, chars:"E", unmodifiedChars:"E"},
+                  "E", "KeyE", KeyboardEvent.DOM_VK_E, "E", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_E,
+                   modifiers:{ctrlKey:1}, chars:"\u0005", unmodifiedChars:"e"},
+                  "e", "KeyE", KeyboardEvent.DOM_VK_E, "e", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_E,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0005", unmodifiedChars:"E"},
+                  "E", "KeyE", KeyboardEvent.DOM_VK_E, "E", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_E,
+                   modifiers:{altKey:1}, chars:"", unmodifiedChars:"e"},
+                  "Dead", "KeyE", KeyboardEvent.DOM_VK_E, "\u00B4", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // dead key
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_E,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00B4", unmodifiedChars:"E"},
+                  "\u00B4", "KeyE", KeyboardEvent.DOM_VK_E, "\u00B4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_E,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0005", unmodifiedChars:"e"},
+                  "Dead", "KeyE", KeyboardEvent.DOM_VK_E, "e", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_E,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0005", unmodifiedChars:"E"},
+                  "\u00B4", "KeyE", KeyboardEvent.DOM_VK_E, "E", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_E,
+                   modifiers:{metaKey:1}, chars:"e", unmodifiedChars:"e"},
+                  "e", "KeyE", KeyboardEvent.DOM_VK_E, "e", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_F,
+                   modifiers:{}, chars:"f", unmodifiedChars:"f"},
+                  "f", "KeyF", KeyboardEvent.DOM_VK_F, "f", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_F,
+                   modifiers:{shiftKey:1}, chars:"F", unmodifiedChars:"F"},
+                  "F", "KeyF", KeyboardEvent.DOM_VK_F, "F", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_F,
+                   modifiers:{ctrlKey:1}, chars:"\u0006", unmodifiedChars:"f"},
+                  "f", "KeyF", KeyboardEvent.DOM_VK_F, "f", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_F,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0006", unmodifiedChars:"F"},
+                  "F", "KeyF", KeyboardEvent.DOM_VK_F, "F", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_F,
+                   modifiers:{altKey:1}, chars:"\u0192", unmodifiedChars:"f"},
+                  "\u0192", "KeyF", KeyboardEvent.DOM_VK_F, "\u0192", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_F,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00CF", unmodifiedChars:"F"},
+                  "\u00CF", "KeyF", KeyboardEvent.DOM_VK_F, "\u00CF", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_F,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0006", unmodifiedChars:"f"},
+                  "\u0192", "KeyF", KeyboardEvent.DOM_VK_F, "f", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_F,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0006", unmodifiedChars:"F"},
+                  "\u00CF", "KeyF", KeyboardEvent.DOM_VK_F, "F", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // XXX This test starts fullscreen mode.
+    // yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_F,
+    //                modifiers:{metaKey:1}, chars:"f", unmodifiedChars:"f"},
+    //               "f", "KeyF", KeyboardEvent.DOM_VK_F, "f", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_G,
+                   modifiers:{}, chars:"g", unmodifiedChars:"g"},
+                  "g", "KeyG", KeyboardEvent.DOM_VK_G, "g", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_G,
+                   modifiers:{shiftKey:1}, chars:"G", unmodifiedChars:"G"},
+                  "G", "KeyG", KeyboardEvent.DOM_VK_G, "G", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_G,
+                   modifiers:{ctrlKey:1}, chars:"\u0007", unmodifiedChars:"g"},
+                  "g", "KeyG", KeyboardEvent.DOM_VK_G, "g", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_G,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0007", unmodifiedChars:"G"},
+                  "G", "KeyG", KeyboardEvent.DOM_VK_G, "G", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_G,
+                   modifiers:{altKey:1}, chars:"\u00A9", unmodifiedChars:"g"},
+                  "\u00A9", "KeyG", KeyboardEvent.DOM_VK_G, "\u00A9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_G,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u02DD", unmodifiedChars:"G"},
+                  "\u02DD", "KeyG", KeyboardEvent.DOM_VK_G, "\u02DD", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_G,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0007", unmodifiedChars:"g"},
+                  "\u00A9", "KeyG", KeyboardEvent.DOM_VK_G, "g", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_G,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0007", unmodifiedChars:"G"},
+                  "\u02DD", "KeyG", KeyboardEvent.DOM_VK_G, "G", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_G,
+                   modifiers:{metaKey:1}, chars:"g", unmodifiedChars:"g"},
+                  "g", "KeyG", KeyboardEvent.DOM_VK_G, "g", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_H,
+                   modifiers:{}, chars:"h", unmodifiedChars:"h"},
+                  "h", "KeyH", KeyboardEvent.DOM_VK_H, "h", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_H,
+                   modifiers:{shiftKey:1}, chars:"H", unmodifiedChars:"H"},
+                  "H", "KeyH", KeyboardEvent.DOM_VK_H, "H", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_H,
+                   modifiers:{ctrlKey:1}, chars:"\u0008", unmodifiedChars:"h"},
+                  "h", "KeyH", KeyboardEvent.DOM_VK_H, "h", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_H,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0008", unmodifiedChars:"H"},
+                  "H", "KeyH", KeyboardEvent.DOM_VK_H, "H", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_H,
+                   modifiers:{altKey:1}, chars:"\u02D9", unmodifiedChars:"h"},
+                  "\u02D9", "KeyH", KeyboardEvent.DOM_VK_H, "\u02D9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_H,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00D3", unmodifiedChars:"H"},
+                  "\u00D3", "KeyH", KeyboardEvent.DOM_VK_H, "\u00D3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_H,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0008", unmodifiedChars:"h"},
+                  "\u02D9", "KeyH", KeyboardEvent.DOM_VK_H, "h", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_H,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0008", unmodifiedChars:"H"},
+                  "\u00D3", "KeyH", KeyboardEvent.DOM_VK_H, "H", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_H,
+                   modifiers:{metaKey:1}, chars:"h", unmodifiedChars:"h"},
+                  "h", "KeyH", KeyboardEvent.DOM_VK_H, "h", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_I,
+                   modifiers:{}, chars:"i", unmodifiedChars:"i"},
+                  "i", "KeyI", KeyboardEvent.DOM_VK_I, "i", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_I,
+                   modifiers:{shiftKey:1}, chars:"I", unmodifiedChars:"I"},
+                  "I", "KeyI", KeyboardEvent.DOM_VK_I, "I", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_I,
+                   modifiers:{ctrlKey:1}, chars:"\u0009", unmodifiedChars:"i"},
+                  "i", "KeyI", KeyboardEvent.DOM_VK_I, "i", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_I,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0009", unmodifiedChars:"I"},
+                  "I", "KeyI", KeyboardEvent.DOM_VK_I, "I", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_I,
+                   modifiers:{altKey:1}, chars:"", unmodifiedChars:"i"},
+                  "Dead", "KeyI", KeyboardEvent.DOM_VK_I, "\u02C6", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // dead key
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_I,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u02C6", unmodifiedChars:"I"},
+                  "\u02C6", "KeyI", KeyboardEvent.DOM_VK_I, "\u02C6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_I,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0009", unmodifiedChars:"i"},
+                  "Dead", "KeyI", KeyboardEvent.DOM_VK_I, "i", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_I,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0009", unmodifiedChars:"I"},
+                  "\u02C6", "KeyI", KeyboardEvent.DOM_VK_I, "I", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // XXX This test causes memory leak.
+    // yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_I,
+    //                modifiers:{metaKey:1}, chars:"i", unmodifiedChars:"i"},
+    //               "i", "KeyI", KeyboardEvent.DOM_VK_I, "i", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_J,
+                   modifiers:{}, chars:"j", unmodifiedChars:"j"},
+                  "j", "KeyJ", KeyboardEvent.DOM_VK_J, "j", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_J,
+                   modifiers:{shiftKey:1}, chars:"J", unmodifiedChars:"J"},
+                  "J", "KeyJ", KeyboardEvent.DOM_VK_J, "J", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_J,
+                   modifiers:{ctrlKey:1}, chars:"\u000A", unmodifiedChars:"j"},
+                  "j", "KeyJ", KeyboardEvent.DOM_VK_J, "j", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_J,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000A", unmodifiedChars:"J"},
+                  "J", "KeyJ", KeyboardEvent.DOM_VK_J, "J", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_J,
+                   modifiers:{altKey:1}, chars:"\u2206", unmodifiedChars:"j"},
+                  "\u2206", "KeyJ", KeyboardEvent.DOM_VK_J, "\u2206", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_J,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00D4", unmodifiedChars:"J"},
+                  "\u00D4", "KeyJ", KeyboardEvent.DOM_VK_J, "\u00D4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_J,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u000A", unmodifiedChars:"j"},
+                  "\u2206", "KeyJ", KeyboardEvent.DOM_VK_J, "j", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_J,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u000A", unmodifiedChars:"J"},
+                  "\u00D4", "KeyJ", KeyboardEvent.DOM_VK_J, "J", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_J,
+                   modifiers:{metaKey:1}, chars:"j", unmodifiedChars:"j"},
+                  "j", "KeyJ", KeyboardEvent.DOM_VK_J, "j", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_K,
+                   modifiers:{}, chars:"k", unmodifiedChars:"k"},
+                  "k", "KeyK", KeyboardEvent.DOM_VK_K, "k", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_K,
+                   modifiers:{shiftKey:1}, chars:"K", unmodifiedChars:"K"},
+                  "K", "KeyK", KeyboardEvent.DOM_VK_K, "K", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_K,
+                   modifiers:{ctrlKey:1}, chars:"\u000B", unmodifiedChars:"k"},
+                  "k", "KeyK", KeyboardEvent.DOM_VK_K, "k", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_K,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000B", unmodifiedChars:"K"},
+                  "K", "KeyK", KeyboardEvent.DOM_VK_K, "K", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_K,
+                   modifiers:{altKey:1}, chars:"\u02DA", unmodifiedChars:"k"},
+                  "\u02DA", "KeyK", KeyboardEvent.DOM_VK_K, "\u02DA", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_K,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\uF8FF", unmodifiedChars:"K"},
+                  "\uF8FF", "KeyK", KeyboardEvent.DOM_VK_K, "\uF8FF", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_K,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u000B", unmodifiedChars:"k"},
+                  "\u02DA", "KeyK", KeyboardEvent.DOM_VK_K, "k", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_K,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u000B", unmodifiedChars:"K"},
+                  "\uF8FF", "KeyK", KeyboardEvent.DOM_VK_K, "K", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_K,
+                   modifiers:{metaKey:1}, chars:"k", unmodifiedChars:"k"},
+                  "k", "KeyK", KeyboardEvent.DOM_VK_K, "k", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_L,
+                   modifiers:{}, chars:"l", unmodifiedChars:"l"},
+                  "l", "KeyL", KeyboardEvent.DOM_VK_L, "l", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_L,
+                   modifiers:{shiftKey:1}, chars:"L", unmodifiedChars:"L"},
+                  "L", "KeyL", KeyboardEvent.DOM_VK_L, "L", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_L,
+                   modifiers:{ctrlKey:1}, chars:"\u000C", unmodifiedChars:"l"},
+                  "l", "KeyL", KeyboardEvent.DOM_VK_L, "l", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_L,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000C", unmodifiedChars:"L"},
+                  "L", "KeyL", KeyboardEvent.DOM_VK_L, "L", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_L,
+                   modifiers:{altKey:1}, chars:"\u00AC", unmodifiedChars:"l"},
+                  "\u00AC", "KeyL", KeyboardEvent.DOM_VK_L, "\u00AC", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_L,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00D2", unmodifiedChars:"L"},
+                  "\u00D2", "KeyL", KeyboardEvent.DOM_VK_L, "\u00D2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_L,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u000C", unmodifiedChars:"l"},
+                  "\u00AC", "KeyL", KeyboardEvent.DOM_VK_L, "l", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_L,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u000C", unmodifiedChars:"L"},
+                  "\u00D2", "KeyL", KeyboardEvent.DOM_VK_L, "L", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_L,
+                   modifiers:{metaKey:1}, chars:"l", unmodifiedChars:"l"},
+                  "l", "KeyL", KeyboardEvent.DOM_VK_L, "l", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_M,
+                   modifiers:{}, chars:"m", unmodifiedChars:"m"},
+                  "m", "KeyM", KeyboardEvent.DOM_VK_M, "m", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_M,
+                   modifiers:{shiftKey:1}, chars:"M", unmodifiedChars:"M"},
+                  "M", "KeyM", KeyboardEvent.DOM_VK_M, "M", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_M,
+                   modifiers:{ctrlKey:1}, chars:"\u000D", unmodifiedChars:"m"},
+                  "m", "KeyM", KeyboardEvent.DOM_VK_M, "m", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_M,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000D", unmodifiedChars:"M"},
+                  "M", "KeyM", KeyboardEvent.DOM_VK_M, "M", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_M,
+                   modifiers:{altKey:1}, chars:"\u00B5", unmodifiedChars:"m"},
+                  "\u00B5", "KeyM", KeyboardEvent.DOM_VK_M, "\u00B5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_M,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00C2", unmodifiedChars:"M"},
+                  "\u00C2", "KeyM", KeyboardEvent.DOM_VK_M, "\u00C2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_M,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u000D", unmodifiedChars:"m"},
+                  "\u00B5", "KeyM", KeyboardEvent.DOM_VK_M, "m", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_M,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u000D", unmodifiedChars:"M"},
+                  "\u00C2", "KeyM", KeyboardEvent.DOM_VK_M, "M", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_M,
+                   modifiers:{metaKey:1}, chars:"m", unmodifiedChars:"m"},
+                  "m", "KeyM", KeyboardEvent.DOM_VK_M, "m", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_N,
+                   modifiers:{}, chars:"n", unmodifiedChars:"n"},
+                  "n", "KeyN", KeyboardEvent.DOM_VK_N, "n", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_N,
+                   modifiers:{shiftKey:1}, chars:"N", unmodifiedChars:"N"},
+                  "N", "KeyN", KeyboardEvent.DOM_VK_N, "N", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_N,
+                   modifiers:{ctrlKey:1}, chars:"\u000E", unmodifiedChars:"n"},
+                  "n", "KeyN", KeyboardEvent.DOM_VK_N, "n", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_N,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000E", unmodifiedChars:"N"},
+                  "N", "KeyN", KeyboardEvent.DOM_VK_N, "N", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_N,
+                   modifiers:{altKey:1}, chars:"", unmodifiedChars:"n"},
+                  "Dead", "KeyN", KeyboardEvent.DOM_VK_N, "\u02DC", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // dead key
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_N,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u02DC", unmodifiedChars:"N"},
+                  "\u02DC", "KeyN", KeyboardEvent.DOM_VK_N, "\u02DC", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_N,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u000E", unmodifiedChars:"n"},
+                  "Dead", "KeyN", KeyboardEvent.DOM_VK_N, "n", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_N,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u000E", unmodifiedChars:"N"},
+                  "\u02DC", "KeyN", KeyboardEvent.DOM_VK_N, "N", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_N,
+                   modifiers:{metaKey:1}, chars:"n", unmodifiedChars:"n"},
+                  "n", "KeyN", KeyboardEvent.DOM_VK_N, "n", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_O,
+                   modifiers:{}, chars:"o", unmodifiedChars:"o"},
+                  "o", "KeyO", KeyboardEvent.DOM_VK_O, "o", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_O,
+                   modifiers:{shiftKey:1}, chars:"O", unmodifiedChars:"O"},
+                  "O", "KeyO", KeyboardEvent.DOM_VK_O, "O", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_O,
+                   modifiers:{ctrlKey:1}, chars:"\u000F", unmodifiedChars:"o"},
+                  "o", "KeyO", KeyboardEvent.DOM_VK_O, "o", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_O,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000F", unmodifiedChars:"O"},
+                  "O", "KeyO", KeyboardEvent.DOM_VK_O, "O", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_O,
+                   modifiers:{altKey:1}, chars:"\u00F8", unmodifiedChars:"o"},
+                  "\u00F8", "KeyO", KeyboardEvent.DOM_VK_O, "\u00F8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_O,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00D8", unmodifiedChars:"O"},
+                  "\u00D8", "KeyO", KeyboardEvent.DOM_VK_O, "\u00D8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_O,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u000F", unmodifiedChars:"o"},
+                  "\u00F8", "KeyO", KeyboardEvent.DOM_VK_O, "o", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_O,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u000F", unmodifiedChars:"O"},
+                  "\u00D8", "KeyO", KeyboardEvent.DOM_VK_O, "O", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_O,
+                   modifiers:{metaKey:1}, chars:"o", unmodifiedChars:"o"},
+                  "o", "KeyO", KeyboardEvent.DOM_VK_O, "o", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_P,
+                   modifiers:{}, chars:"p", unmodifiedChars:"p"},
+                  "p", "KeyP", KeyboardEvent.DOM_VK_P, "p", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_P,
+                   modifiers:{shiftKey:1}, chars:"P", unmodifiedChars:"P"},
+                  "P", "KeyP", KeyboardEvent.DOM_VK_P, "P", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_P,
+                   modifiers:{ctrlKey:1}, chars:"\u0010", unmodifiedChars:"p"},
+                  "p", "KeyP", KeyboardEvent.DOM_VK_P, "p", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_P,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0010", unmodifiedChars:"P"},
+                  "P", "KeyP", KeyboardEvent.DOM_VK_P, "P", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_P,
+                   modifiers:{altKey:1}, chars:"\u03C0", unmodifiedChars:"p"},
+                  "\u03C0", "KeyP", KeyboardEvent.DOM_VK_P, "\u03C0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_P,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u220F", unmodifiedChars:"P"},
+                  "\u220F", "KeyP", KeyboardEvent.DOM_VK_P, "\u220F", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_P,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0010", unmodifiedChars:"p"},
+                  "\u03C0", "KeyP", KeyboardEvent.DOM_VK_P, "p", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_P,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0010", unmodifiedChars:"P"},
+                  "\u220F", "KeyP", KeyboardEvent.DOM_VK_P, "P", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // XXX This test starts private browsing mode (stopped at the confirmation dialog)
+    // yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_P,
+    //                modifiers:{metaKey:1}, chars:"p", unmodifiedChars:"p"},
+    //               "p", "KeyP", KeyboardEvent.DOM_VK_P, "p", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Q,
+                   modifiers:{}, chars:"q", unmodifiedChars:"q"},
+                  "q", "KeyQ", KeyboardEvent.DOM_VK_Q, "q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Q,
+                   modifiers:{shiftKey:1}, chars:"Q", unmodifiedChars:"Q"},
+                  "Q", "KeyQ", KeyboardEvent.DOM_VK_Q, "Q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Q,
+                   modifiers:{ctrlKey:1}, chars:"\u0011", unmodifiedChars:"q"},
+                  "q", "KeyQ", KeyboardEvent.DOM_VK_Q, "q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Q,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0011", unmodifiedChars:"Q"},
+                  "Q", "KeyQ", KeyboardEvent.DOM_VK_Q, "Q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Q,
+                   modifiers:{altKey:1}, chars:"\u0153", unmodifiedChars:"q"},
+                  "\u0153", "KeyQ", KeyboardEvent.DOM_VK_Q, "\u0153", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Q,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u0152", unmodifiedChars:"Q"},
+                  "\u0152", "KeyQ", KeyboardEvent.DOM_VK_Q, "\u0152", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Q,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0011", unmodifiedChars:"q"},
+                  "\u0153", "KeyQ", KeyboardEvent.DOM_VK_Q, "q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Q,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0011", unmodifiedChars:"Q"},
+                  "\u0152", "KeyQ", KeyboardEvent.DOM_VK_Q, "Q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Q,
+                   modifiers:{metaKey:1}, chars:"q", unmodifiedChars:"q"},
+                  "q", "KeyQ", KeyboardEvent.DOM_VK_Q, "q", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_R,
+                   modifiers:{}, chars:"r", unmodifiedChars:"r"},
+                  "r", "KeyR", KeyboardEvent.DOM_VK_R, "r", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_R,
+                   modifiers:{shiftKey:1}, chars:"R", unmodifiedChars:"R"},
+                  "R", "KeyR", KeyboardEvent.DOM_VK_R, "R", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_R,
+                   modifiers:{ctrlKey:1}, chars:"\u0012", unmodifiedChars:"r"},
+                  "r", "KeyR", KeyboardEvent.DOM_VK_R, "r", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_R,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0012", unmodifiedChars:"R"},
+                  "R", "KeyR", KeyboardEvent.DOM_VK_R, "R", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_R,
+                   modifiers:{altKey:1}, chars:"\u00AE", unmodifiedChars:"r"},
+                  "\u00AE", "KeyR", KeyboardEvent.DOM_VK_R, "\u00AE", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_R,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u2030", unmodifiedChars:"R"},
+                  "\u2030", "KeyR", KeyboardEvent.DOM_VK_R, "\u2030", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_R,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0012", unmodifiedChars:"r"},
+                  "\u00AE", "KeyR", KeyboardEvent.DOM_VK_R, "r", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_R,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0012", unmodifiedChars:"R"},
+                  "\u2030", "KeyR", KeyboardEvent.DOM_VK_R, "R", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // XXX This test makes some tabs and dialogs.
+    // yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_R,
+    //                modifiers:{metaKey:1}, chars:"r", unmodifiedChars:"r"},
+    //               "r", "KeyR", KeyboardEvent.DOM_VK_R, "r", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{}, chars:"s", unmodifiedChars:"s"},
+                  "s", "KeyS", KeyboardEvent.DOM_VK_S, "s", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{shiftKey:1}, chars:"S", unmodifiedChars:"S"},
+                  "S", "KeyS", KeyboardEvent.DOM_VK_S, "S", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{ctrlKey:1}, chars:"\u0013", unmodifiedChars:"s"},
+                  "s", "KeyS", KeyboardEvent.DOM_VK_S, "s", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0013", unmodifiedChars:"S"},
+                  "S", "KeyS", KeyboardEvent.DOM_VK_S, "S", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{altKey:1}, chars:"\u00DF", unmodifiedChars:"s"},
+                  "\u00DF", "KeyS", KeyboardEvent.DOM_VK_S, "\u00DF", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00CD", unmodifiedChars:"S"},
+                  "\u00CD", "KeyS", KeyboardEvent.DOM_VK_S, "\u00CD", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0013", unmodifiedChars:"s"},
+                  "\u00DF", "KeyS", KeyboardEvent.DOM_VK_S, "s", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0013", unmodifiedChars:"S"},
+                  "\u00CD", "KeyS", KeyboardEvent.DOM_VK_S, "S", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{metaKey:1}, chars:"s", unmodifiedChars:"s"},
+                  "s", "KeyS", KeyboardEvent.DOM_VK_S, "s", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_T,
+                   modifiers:{}, chars:"t", unmodifiedChars:"t"},
+                  "t", "KeyT", KeyboardEvent.DOM_VK_T, "t", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_T,
+                   modifiers:{shiftKey:1}, chars:"T", unmodifiedChars:"T"},
+                  "T", "KeyT", KeyboardEvent.DOM_VK_T, "T", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_T,
+                   modifiers:{ctrlKey:1}, chars:"\u0014", unmodifiedChars:"t"},
+                  "t", "KeyT", KeyboardEvent.DOM_VK_T, "t", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_T,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0014", unmodifiedChars:"T"},
+                  "T", "KeyT", KeyboardEvent.DOM_VK_T, "T", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_T,
+                   modifiers:{altKey:1}, chars:"\u2020", unmodifiedChars:"t"},
+                  "\u2020", "KeyT", KeyboardEvent.DOM_VK_T, "\u2020", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_T,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u02C7", unmodifiedChars:"T"},
+                  "\u02C7", "KeyT", KeyboardEvent.DOM_VK_T, "\u02C7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_T,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0014", unmodifiedChars:"t"},
+                  "\u2020", "KeyT", KeyboardEvent.DOM_VK_T, "t", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_T,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0014", unmodifiedChars:"T"},
+                  "\u02C7", "KeyT", KeyboardEvent.DOM_VK_T, "T", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_T,
+                   modifiers:{metaKey:1}, chars:"t", unmodifiedChars:"t"},
+                  "t", "KeyT", KeyboardEvent.DOM_VK_T, "t", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_U,
+                   modifiers:{}, chars:"u", unmodifiedChars:"u"},
+                  "u", "KeyU", KeyboardEvent.DOM_VK_U, "u", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_U,
+                   modifiers:{shiftKey:1}, chars:"U", unmodifiedChars:"U"},
+                  "U", "KeyU", KeyboardEvent.DOM_VK_U, "U", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_U,
+                   modifiers:{ctrlKey:1}, chars:"\u0015", unmodifiedChars:"u"},
+                  "u", "KeyU", KeyboardEvent.DOM_VK_U, "u", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_U,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0015", unmodifiedChars:"U"},
+                  "U", "KeyU", KeyboardEvent.DOM_VK_U, "U", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_U,
+                   modifiers:{altKey:1}, chars:"", unmodifiedChars:"u"},
+                  "Dead", "KeyU", KeyboardEvent.DOM_VK_U, "\u00A8", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // dead key
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_U,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00A8", unmodifiedChars:"U"},
+                  "\u00A8", "KeyU", KeyboardEvent.DOM_VK_U, "\u00A8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_U,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0015", unmodifiedChars:"u"},
+                  "Dead", "KeyU", KeyboardEvent.DOM_VK_U, "u", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_U,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0015", unmodifiedChars:"U"},
+                  "\u00A8", "KeyU", KeyboardEvent.DOM_VK_U, "U", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_U,
+                   modifiers:{metaKey:1}, chars:"u", unmodifiedChars:"u"},
+                  "u", "KeyU", KeyboardEvent.DOM_VK_U, "u", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_V,
+                   modifiers:{}, chars:"v", unmodifiedChars:"v"},
+                  "v", "KeyV", KeyboardEvent.DOM_VK_V, "v", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_V,
+                   modifiers:{shiftKey:1}, chars:"V", unmodifiedChars:"V"},
+                  "V", "KeyV", KeyboardEvent.DOM_VK_V, "V", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_V,
+                   modifiers:{ctrlKey:1}, chars:"\u0016", unmodifiedChars:"v"},
+                  "v", "KeyV", KeyboardEvent.DOM_VK_V, "v", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_V,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0016", unmodifiedChars:"V"},
+                  "V", "KeyV", KeyboardEvent.DOM_VK_V, "V", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_V,
+                   modifiers:{altKey:1}, chars:"\u221A", unmodifiedChars:"v"},
+                  "\u221A", "KeyV", KeyboardEvent.DOM_VK_V, "\u221A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_V,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u25CA", unmodifiedChars:"V"},
+                  "\u25CA", "KeyV", KeyboardEvent.DOM_VK_V, "\u25CA", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_V,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0016", unmodifiedChars:"v"},
+                  "\u221A", "KeyV", KeyboardEvent.DOM_VK_V, "v", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_V,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0016", unmodifiedChars:"V"},
+                  "\u25CA", "KeyV", KeyboardEvent.DOM_VK_V, "V", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_V,
+                   modifiers:{metaKey:1}, chars:"v", unmodifiedChars:"v"},
+                  "v", "KeyV", KeyboardEvent.DOM_VK_V, "v", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_W,
+                   modifiers:{}, chars:"w", unmodifiedChars:"w"},
+                  "w", "KeyW", KeyboardEvent.DOM_VK_W, "w", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_W,
+                   modifiers:{shiftKey:1}, chars:"W", unmodifiedChars:"W"},
+                  "W", "KeyW", KeyboardEvent.DOM_VK_W, "W", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_W,
+                   modifiers:{ctrlKey:1}, chars:"\u0017", unmodifiedChars:"w"},
+                  "w", "KeyW", KeyboardEvent.DOM_VK_W, "w", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_W,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0017", unmodifiedChars:"W"},
+                  "W", "KeyW", KeyboardEvent.DOM_VK_W, "W", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_W,
+                   modifiers:{altKey:1}, chars:"\u2211", unmodifiedChars:"w"},
+                  "\u2211", "KeyW", KeyboardEvent.DOM_VK_W, "\u2211", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_W,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u201E", unmodifiedChars:"W"},
+                  "\u201E", "KeyW", KeyboardEvent.DOM_VK_W, "\u201E", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_W,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0017", unmodifiedChars:"w"},
+                  "\u2211", "KeyW", KeyboardEvent.DOM_VK_W, "w", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_W,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0017", unmodifiedChars:"W"},
+                  "\u201E", "KeyW", KeyboardEvent.DOM_VK_W, "W", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_W,
+                   modifiers:{metaKey:1}, chars:"w", unmodifiedChars:"w"},
+                  "w", "KeyW", KeyboardEvent.DOM_VK_W, "w", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_X,
+                   modifiers:{}, chars:"x", unmodifiedChars:"x"},
+                  "x", "KeyX", KeyboardEvent.DOM_VK_X, "x", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_X,
+                   modifiers:{shiftKey:1}, chars:"X", unmodifiedChars:"X"},
+                  "X", "KeyX", KeyboardEvent.DOM_VK_X, "X", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_X,
+                   modifiers:{ctrlKey:1}, chars:"\u0018", unmodifiedChars:"x"},
+                  "x", "KeyX", KeyboardEvent.DOM_VK_X, "x", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_X,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0018", unmodifiedChars:"X"},
+                  "X", "KeyX", KeyboardEvent.DOM_VK_X, "X", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_X,
+                   modifiers:{altKey:1}, chars:"\u2248", unmodifiedChars:"x"},
+                  "\u2248", "KeyX", KeyboardEvent.DOM_VK_X, "\u2248", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_X,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u02DB", unmodifiedChars:"X"},
+                  "\u02DB", "KeyX", KeyboardEvent.DOM_VK_X, "\u02DB", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_X,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0018", unmodifiedChars:"x"},
+                  "\u2248", "KeyX", KeyboardEvent.DOM_VK_X, "x", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_X,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0018", unmodifiedChars:"X"},
+                  "\u02DB", "KeyX", KeyboardEvent.DOM_VK_X, "X", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_X,
+                   modifiers:{metaKey:1}, chars:"x", unmodifiedChars:"x"},
+                  "x", "KeyX", KeyboardEvent.DOM_VK_X, "x", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Y,
+                   modifiers:{}, chars:"y", unmodifiedChars:"y"},
+                  "y", "KeyY", KeyboardEvent.DOM_VK_Y, "y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Y,
+                   modifiers:{shiftKey:1}, chars:"Y", unmodifiedChars:"Y"},
+                  "Y", "KeyY", KeyboardEvent.DOM_VK_Y, "Y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Y,
+                   modifiers:{ctrlKey:1}, chars:"\u0019", unmodifiedChars:"y"},
+                  "y", "KeyY", KeyboardEvent.DOM_VK_Y, "y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Y,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0019", unmodifiedChars:"Y"},
+                  "Y", "KeyY", KeyboardEvent.DOM_VK_Y, "Y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Y,
+                   modifiers:{altKey:1}, chars:"\u00A5", unmodifiedChars:"y"},
+                  "\u00A5", "KeyY", KeyboardEvent.DOM_VK_Y, "\u00A5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Y,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00C1", unmodifiedChars:"Y"},
+                  "\u00C1", "KeyY", KeyboardEvent.DOM_VK_Y, "\u00C1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Y,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u0019", unmodifiedChars:"y"},
+                  "\u00A5", "KeyY", KeyboardEvent.DOM_VK_Y, "y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Y,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0019", unmodifiedChars:"Y"},
+                  "\u00C1", "KeyY", KeyboardEvent.DOM_VK_Y, "Y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Y,
+                   modifiers:{metaKey:1}, chars:"y", unmodifiedChars:"y"},
+                  "y", "KeyY", KeyboardEvent.DOM_VK_Y, "y", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Z,
+                   modifiers:{}, chars:"z", unmodifiedChars:"z"},
+                  "z", "KeyZ", KeyboardEvent.DOM_VK_Z, "z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Z,
+                   modifiers:{shiftKey:1}, chars:"Z", unmodifiedChars:"Z"},
+                  "Z", "KeyZ", KeyboardEvent.DOM_VK_Z, "Z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Z,
+                   modifiers:{ctrlKey:1}, chars:"\u001A", unmodifiedChars:"z"},
+                  "z", "KeyZ", KeyboardEvent.DOM_VK_Z, "z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Z,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u001A", unmodifiedChars:"Z"},
+                  "Z", "KeyZ", KeyboardEvent.DOM_VK_Z, "Z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Z,
+                   modifiers:{altKey:1}, chars:"\u03A9", unmodifiedChars:"z"},
+                  "\u03A9", "KeyZ", KeyboardEvent.DOM_VK_Z, "\u03A9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Z,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00B8", unmodifiedChars:"Z"},
+                  "\u00B8", "KeyZ", KeyboardEvent.DOM_VK_Z, "\u00B8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Z,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u001A", unmodifiedChars:"z"},
+                  "\u03A9", "KeyZ", KeyboardEvent.DOM_VK_Z, "z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Z,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u001A", unmodifiedChars:"Z"},
+                  "\u00B8", "KeyZ", KeyboardEvent.DOM_VK_Z, "Z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Z,
+                   modifiers:{metaKey:1}, chars:"z", unmodifiedChars:"z"},
+                  "z", "KeyZ", KeyboardEvent.DOM_VK_Z, "z", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // numeric
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{shiftKey:1}, chars:"!", unmodifiedChars:"!"},
+                  "!", "Digit1", KeyboardEvent.DOM_VK_1, "!", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{ctrlKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"1", unmodifiedChars:"!"},
+                  "!", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{altKey:1}, chars:"\u00A1", unmodifiedChars:"1"},
+                  "\u00A1", "Digit1", KeyboardEvent.DOM_VK_1, "\u00A1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u2044", unmodifiedChars:"!"},
+                  "\u2044", "Digit1", KeyboardEvent.DOM_VK_1, "\u2044", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "\u00A1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"1", unmodifiedChars:"!"},
+                  "\u2044", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{metaKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{shiftKey:1}, chars:"@", unmodifiedChars:"@"},
+                  "@", "Digit2", KeyboardEvent.DOM_VK_2, "@", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{ctrlKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0000", unmodifiedChars:"@"},
+                  "@", "Digit2", KeyboardEvent.DOM_VK_2, "@", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{altKey:1}, chars:"\u2122", unmodifiedChars:"2"},
+                  "\u2122", "Digit2", KeyboardEvent.DOM_VK_2, "\u2122", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u20AC", unmodifiedChars:"@"},
+                  "\u20AC", "Digit2", KeyboardEvent.DOM_VK_2, "\u20AC", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "\u2122", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0000", unmodifiedChars:"@"},
+                  "\u20AC", "Digit2", KeyboardEvent.DOM_VK_2, "@", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{metaKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{shiftKey:1}, chars:"#", unmodifiedChars:"#"},
+                  "#", "Digit3", KeyboardEvent.DOM_VK_3, "#", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{ctrlKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"3", unmodifiedChars:"#"},
+                  "#", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{altKey:1}, chars:"\u00A3", unmodifiedChars:"3"},
+                  "\u00A3", "Digit3", KeyboardEvent.DOM_VK_3, "\u00A3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u2039", unmodifiedChars:"#"},
+                  "\u2039", "Digit3", KeyboardEvent.DOM_VK_3, "\u2039", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "\u00A3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"3", unmodifiedChars:"#"},
+                  "\u2039", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{metaKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{shiftKey:1}, chars:"$", unmodifiedChars:"$"},
+                  "$", "Digit4", KeyboardEvent.DOM_VK_4, "$", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{ctrlKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"4", unmodifiedChars:"$"},
+                  "$", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{altKey:1}, chars:"\u00A2", unmodifiedChars:"4"},
+                  "\u00A2", "Digit4", KeyboardEvent.DOM_VK_4, "\u00A2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u203A", unmodifiedChars:"$"},
+                  "\u203A", "Digit4", KeyboardEvent.DOM_VK_4, "\u203A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "\u00A2", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"4", unmodifiedChars:"$"},
+                  "\u203A", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{metaKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{shiftKey:1}, chars:"%", unmodifiedChars:"%"},
+                  "%", "Digit5", KeyboardEvent.DOM_VK_5, "%", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{ctrlKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"5", unmodifiedChars:"%"},
+                  "%", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{altKey:1}, chars:"\u221E", unmodifiedChars:"5"},
+                  "\u221E", "Digit5", KeyboardEvent.DOM_VK_5, "\u221E", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\uFB01", unmodifiedChars:"%"},
+                  "\uFB01", "Digit5", KeyboardEvent.DOM_VK_5, "\uFB01", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "\u221E", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"5", unmodifiedChars:"%"},
+                  "\uFB01", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{metaKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Digit6", KeyboardEvent.DOM_VK_6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{shiftKey:1}, chars:"^", unmodifiedChars:"^"},
+                  "^", "Digit6", KeyboardEvent.DOM_VK_6, "^", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{ctrlKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Digit6", KeyboardEvent.DOM_VK_6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u001E", unmodifiedChars:"^"},
+                  "^", "Digit6", KeyboardEvent.DOM_VK_6, "\u0000", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{altKey:1}, chars:"\u00A7", unmodifiedChars:"6"},
+                  "\u00A7", "Digit6", KeyboardEvent.DOM_VK_6, "\u00A7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\uFB02", unmodifiedChars:"^"},
+                  "\uFB02", "Digit6", KeyboardEvent.DOM_VK_6, "\uFB02", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "\u00A7", "Digit6", KeyboardEvent.DOM_VK_6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u001E", unmodifiedChars:"^"},
+                  "\uFB02", "Digit6", KeyboardEvent.DOM_VK_6, "\u0000", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{metaKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Digit6", KeyboardEvent.DOM_VK_6, "6", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{shiftKey:1}, chars:"&", unmodifiedChars:"&"},
+                  "&", "Digit7", KeyboardEvent.DOM_VK_7, "&", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{ctrlKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"7", unmodifiedChars:"&"},
+                  "&", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{altKey:1}, chars:"\u00B6", unmodifiedChars:"7"},
+                  "\u00B6", "Digit7", KeyboardEvent.DOM_VK_7, "\u00B6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u2021", unmodifiedChars:"&"},
+                  "\u2021", "Digit7", KeyboardEvent.DOM_VK_7, "\u2021", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "\u00B6", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"7", unmodifiedChars:"&"},
+                  "\u2021", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{metaKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{shiftKey:1}, chars:"*", unmodifiedChars:"*"},
+                  "*", "Digit8", KeyboardEvent.DOM_VK_8, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{ctrlKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"8", unmodifiedChars:"*"},
+                  "*", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{altKey:1}, chars:"\u2022", unmodifiedChars:"8"},
+                  "\u2022", "Digit8", KeyboardEvent.DOM_VK_8, "\u2022", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00B0", unmodifiedChars:"*"},
+                  "\u00B0", "Digit8", KeyboardEvent.DOM_VK_8, "\u00B0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "\u2022", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"8", unmodifiedChars:"*"},
+                  "\u00B0", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{metaKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{shiftKey:1}, chars:"(", unmodifiedChars:"("},
+                  "(", "Digit9", KeyboardEvent.DOM_VK_9, "(", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{ctrlKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"9", unmodifiedChars:"("},
+                  "(", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{altKey:1}, chars:"\u00AA", unmodifiedChars:"9"},
+                  "\u00AA", "Digit9", KeyboardEvent.DOM_VK_9, "\u00AA", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00B7", unmodifiedChars:"("},
+                  "\u00B7", "Digit9", KeyboardEvent.DOM_VK_9, "\u00B7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "\u00AA", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"9", unmodifiedChars:"("},
+                  "\u00B7", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{metaKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{shiftKey:1}, chars:")", unmodifiedChars:")"},
+                  ")", "Digit0", KeyboardEvent.DOM_VK_0, ")", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{ctrlKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"0", unmodifiedChars:")"},
+                  ")", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{altKey:1}, chars:"\u00BA", unmodifiedChars:"0"},
+                  "\u00BA", "Digit0", KeyboardEvent.DOM_VK_0, "\u00BA", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u201A", unmodifiedChars:")"},
+                  "\u201A", "Digit0", KeyboardEvent.DOM_VK_0, "\u201A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "\u00BA", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"0", unmodifiedChars:")"},
+                  "\u201A", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{metaKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // other chracters
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Grave,
+                   modifiers:{}, chars:"`", unmodifiedChars:"`"},
+                  "`", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "`", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Grave,
+                   modifiers:{shiftKey:1}, chars:"~", unmodifiedChars:"~"},
+                  "~", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "~", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Grave,
+                   modifiers:{ctrlKey:1}, chars:"`", unmodifiedChars:"`"},
+                  "`", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "`", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Grave,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"`", unmodifiedChars:"~"},
+                  "~", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "`", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Grave,
+                   modifiers:{altKey:1}, chars:"", unmodifiedChars:"`"},
+                  "Dead", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "`", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // dead key
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Grave,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"`", unmodifiedChars:"~"},
+                  "`", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "`", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Grave,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"`", unmodifiedChars:"`"},
+                  "Dead", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "`", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Grave,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"`", unmodifiedChars:"~"},
+                  "`", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "`", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Grave,
+                   modifiers:{metaKey:1}, chars:"`", unmodifiedChars:"`"},
+                  "`", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "`", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{}, chars:"-", unmodifiedChars:"-"},
+                  "-", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{shiftKey:1}, chars:"_", unmodifiedChars:"_"},
+                  "_", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "_", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{ctrlKey:1}, chars:"\u001F", unmodifiedChars:"-"},
+                  "-", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u001F", unmodifiedChars:"_"},
+                  "_", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{altKey:1}, chars:"\u2013", unmodifiedChars:"-"},
+                  "\u2013", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "\u2013", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u2014", unmodifiedChars:"_"},
+                  "\u2014", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "\u2014", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u001F", unmodifiedChars:"-"},
+                  "\u2013", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u001F", unmodifiedChars:"_"},
+                  "\u2014", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Minus,
+                   modifiers:{metaKey:1}, chars:"-", unmodifiedChars:"-"},
+                  "-", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "-", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Equal,
+                   modifiers:{}, chars:"=", unmodifiedChars:"="},
+                  "=", "Equal", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Equal,
+                   modifiers:{shiftKey:1}, chars:"+", unmodifiedChars:"+"},
+                  "+", "Equal", KeyboardEvent.DOM_VK_EQUALS, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Equal,
+                   modifiers:{ctrlKey:1}, chars:"=", unmodifiedChars:"="},
+                  "=", "Equal", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Equal,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"=", unmodifiedChars:"+"},
+                  "+", "Equal", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Equal,
+                   modifiers:{altKey:1}, chars:"\u2260", unmodifiedChars:"="},
+                  "\u2260", "Equal", KeyboardEvent.DOM_VK_EQUALS, "\u2260", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Equal,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00B1", unmodifiedChars:"+"},
+                  "\u00B1", "Equal", KeyboardEvent.DOM_VK_EQUALS, "\u00B1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Equal,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"=", unmodifiedChars:"="},
+                  "\u2260", "Equal", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Equal,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"=", unmodifiedChars:"+"},
+                  "\u00B1", "Equal", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Equal,
+                   modifiers:{metaKey:1}, chars:"=", unmodifiedChars:"="},
+                  "=", "Equal", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers:{}, chars:"[", unmodifiedChars:"["},
+                  "[", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "[", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers:{shiftKey:1}, chars:"{", unmodifiedChars:"{"},
+                  "{", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "{", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers:{ctrlKey:1}, chars:"\u001B", unmodifiedChars:"["},
+                  "[", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u001B", unmodifiedChars:"{"},
+                  "{", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers:{altKey:1}, chars:"\u201C", unmodifiedChars:"["},
+                  "\u201C", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "\u201C", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u201D", unmodifiedChars:"{"},
+                  "\u201D", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "\u201D", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u001B", unmodifiedChars:"["},
+                  "\u201C", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u001B", unmodifiedChars:"{"},
+                  "\u201D", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers:{metaKey:1}, chars:"[", unmodifiedChars:"["},
+                  "[", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "[", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_RightBracket,
+                   modifiers:{}, chars:"]", unmodifiedChars:"]"},
+                  "]", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "]", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_RightBracket,
+                   modifiers:{shiftKey:1}, chars:"}", unmodifiedChars:"}"},
+                  "}", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "}", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_RightBracket,
+                   modifiers:{ctrlKey:1}, chars:"\u001D", unmodifiedChars:"]"},
+                  "]", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_RightBracket,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u001D", unmodifiedChars:"}"},
+                  "}", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_RightBracket,
+                   modifiers:{altKey:1}, chars:"\u2018", unmodifiedChars:"]"},
+                  "\u2018", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "\u2018", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_RightBracket,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u2019", unmodifiedChars:"}"},
+                  "\u2019", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "\u2019", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_RightBracket,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u001D", unmodifiedChars:"]"},
+                  "\u2018", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_RightBracket,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u001D", unmodifiedChars:"}"},
+                  "\u2019", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_RightBracket,
+                   modifiers:{metaKey:1}, chars:"]", unmodifiedChars:"]"},
+                  "]", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "]", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Backslash,
+                   modifiers:{}, chars:"\\", unmodifiedChars:"\\"},
+                  "\\", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "\\", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Backslash,
+                   modifiers:{shiftKey:1}, chars:"|", unmodifiedChars:"|"},
+                  "|", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "|", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Backslash,
+                   modifiers:{ctrlKey:1}, chars:"\u001C", unmodifiedChars:"\\"},
+                  "\\", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Backslash,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u001C", unmodifiedChars:"|"},
+                  "|", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Backslash,
+                   modifiers:{altKey:1}, chars:"\u00AB", unmodifiedChars:"\\"},
+                  "\u00AB", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "\u00AB", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Backslash,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00BB", unmodifiedChars:"|"},
+                  "\u00BB", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "\u00BB", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Backslash,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u001C", unmodifiedChars:"\\"},
+                  "\u00AB", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Backslash,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u001C", unmodifiedChars:"|"},
+                  "\u00BB", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Backslash,
+                   modifiers:{metaKey:1}, chars:"\\", unmodifiedChars:"\\"},
+                  "\\", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "\\", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Semicolon,
+                   modifiers:{}, chars:";", unmodifiedChars:";"},
+                  ";", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ";", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Semicolon,
+                   modifiers:{shiftKey:1}, chars:":", unmodifiedChars:":"},
+                  ":", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ":", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Semicolon,
+                   modifiers:{ctrlKey:1}, chars:";", unmodifiedChars:";"},
+                  ";", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ";", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Semicolon,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:";", unmodifiedChars:":"},
+                  ":", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ";", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Semicolon,
+                   modifiers:{altKey:1}, chars:"\u2026", unmodifiedChars:";"},
+                  "\u2026", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, "\u2026", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Semicolon,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00DA", unmodifiedChars:":"},
+                  "\u00DA", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, "\u00DA", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Semicolon,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:";", unmodifiedChars:";"},
+                  "\u2026", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ";", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Semicolon,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:";", unmodifiedChars:":"},
+                  "\u00DA", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ";", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Semicolon,
+                   modifiers:{metaKey:1}, chars:";", unmodifiedChars:";"},
+                  ";", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ";", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Quote,
+                   modifiers:{}, chars:"'", unmodifiedChars:"'"},
+                  "'", "Quote", KeyboardEvent.DOM_VK_QUOTE, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Quote,
+                   modifiers:{shiftKey:1}, chars:"\"", unmodifiedChars:"\""},
+                  "\"", "Quote", KeyboardEvent.DOM_VK_QUOTE, "\"", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Quote,
+                   modifiers:{ctrlKey:1}, chars:"'", unmodifiedChars:"'"},
+                  "'", "Quote", KeyboardEvent.DOM_VK_QUOTE, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Quote,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"'", unmodifiedChars:"\""},
+                  "\"", "Quote", KeyboardEvent.DOM_VK_QUOTE, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Quote,
+                   modifiers:{altKey:1}, chars:"\u00E6", unmodifiedChars:"'"},
+                  "\u00E6", "Quote", KeyboardEvent.DOM_VK_QUOTE, "\u00E6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Quote,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00C6", unmodifiedChars:"\""},
+                  "\u00C6", "Quote", KeyboardEvent.DOM_VK_QUOTE, "\u00C6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Quote,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"'", unmodifiedChars:"'"},
+                  "\u00E6", "Quote", KeyboardEvent.DOM_VK_QUOTE, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Quote,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"'", unmodifiedChars:"\""},
+                  "\u00C6", "Quote", KeyboardEvent.DOM_VK_QUOTE, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Quote,
+                   modifiers:{metaKey:1}, chars:"'", unmodifiedChars:"'"},
+                  "'", "Quote", KeyboardEvent.DOM_VK_QUOTE, "'", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Comma,
+                   modifiers:{}, chars:",", unmodifiedChars:","},
+                  ",", "Comma", KeyboardEvent.DOM_VK_COMMA, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Comma,
+                   modifiers:{shiftKey:1}, chars:"<", unmodifiedChars:"<"},
+                  "<", "Comma", KeyboardEvent.DOM_VK_COMMA, "<", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Comma,
+                   modifiers:{ctrlKey:1}, chars:",", unmodifiedChars:","},
+                  ",", "Comma", KeyboardEvent.DOM_VK_COMMA, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Comma,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:",", unmodifiedChars:"<"},
+                  "<", "Comma", KeyboardEvent.DOM_VK_COMMA, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Comma,
+                   modifiers:{altKey:1}, chars:"\u2264", unmodifiedChars:","},
+                  "\u2264", "Comma", KeyboardEvent.DOM_VK_COMMA, "\u2264", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Comma,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00AF", unmodifiedChars:"<"},
+                  "\u00AF", "Comma", KeyboardEvent.DOM_VK_COMMA, "\u00AF", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Comma,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:",", unmodifiedChars:","},
+                  "\u2264", "Comma", KeyboardEvent.DOM_VK_COMMA, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Comma,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:",", unmodifiedChars:"<"},
+                  "\u00AF", "Comma", KeyboardEvent.DOM_VK_COMMA, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Comma,
+                   modifiers:{metaKey:1}, chars:",", unmodifiedChars:","},
+                  ",", "Comma", KeyboardEvent.DOM_VK_COMMA, ",", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Period,
+                   modifiers:{}, chars:".", unmodifiedChars:"."},
+                  ".", "Period", KeyboardEvent.DOM_VK_PERIOD, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Period,
+                   modifiers:{shiftKey:1}, chars:">", unmodifiedChars:">"},
+                  ">", "Period", KeyboardEvent.DOM_VK_PERIOD, ">", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Period,
+                   modifiers:{ctrlKey:1}, chars:".", unmodifiedChars:"."},
+                  ".", "Period", KeyboardEvent.DOM_VK_PERIOD, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Period,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:".", unmodifiedChars:">"},
+                  ">", "Period", KeyboardEvent.DOM_VK_PERIOD, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Period,
+                   modifiers:{altKey:1}, chars:"\u2265", unmodifiedChars:"."},
+                  "\u2265", "Period", KeyboardEvent.DOM_VK_PERIOD, "\u2265", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Period,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u02D8", unmodifiedChars:">"},
+                  "\u02D8", "Period", KeyboardEvent.DOM_VK_PERIOD, "\u02D8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Period,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:".", unmodifiedChars:"."},
+                  "\u2265", "Period", KeyboardEvent.DOM_VK_PERIOD, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Period,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:".", unmodifiedChars:">"},
+                  "\u02D8", "Period", KeyboardEvent.DOM_VK_PERIOD, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Period,
+                   modifiers:{metaKey:1}, chars:".", unmodifiedChars:"."},
+                  ".", "Period", KeyboardEvent.DOM_VK_PERIOD, ".", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Slash,
+                   modifiers:{}, chars:"/", unmodifiedChars:"/"},
+                  "/", "Slash", KeyboardEvent.DOM_VK_SLASH, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Slash,
+                   modifiers:{shiftKey:1}, chars:"?", unmodifiedChars:"?"},
+                  "?", "Slash", KeyboardEvent.DOM_VK_SLASH, "?", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Slash,
+                   modifiers:{ctrlKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "/", "Slash", KeyboardEvent.DOM_VK_SLASH, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Slash,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"/", unmodifiedChars:"?"},
+                  "?", "Slash", KeyboardEvent.DOM_VK_SLASH, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Slash,
+                   modifiers:{altKey:1}, chars:"\u00F7", unmodifiedChars:"/"},
+                  "\u00F7", "Slash", KeyboardEvent.DOM_VK_SLASH, "\u00F7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Slash,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00BF", unmodifiedChars:"?"},
+                  "\u00BF", "Slash", KeyboardEvent.DOM_VK_SLASH, "\u00BF", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Slash,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "\u00F7", "Slash", KeyboardEvent.DOM_VK_SLASH, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Slash,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"/", unmodifiedChars:"?"},
+                  "\u00BF", "Slash", KeyboardEvent.DOM_VK_SLASH, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Slash,
+                   modifiers:{metaKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "/", "Slash", KeyboardEvent.DOM_VK_SLASH, "/", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // numpad
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad1,
+                   modifiers:{numericKeyPadKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Numpad1", KeyboardEvent.DOM_VK_NUMPAD1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad1,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Numpad1", KeyboardEvent.DOM_VK_NUMPAD1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad1,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Numpad1", KeyboardEvent.DOM_VK_NUMPAD1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad1,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Numpad1", KeyboardEvent.DOM_VK_NUMPAD1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad1,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Numpad1", KeyboardEvent.DOM_VK_NUMPAD1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad1,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Numpad1", KeyboardEvent.DOM_VK_NUMPAD1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad1,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Numpad1", KeyboardEvent.DOM_VK_NUMPAD1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad1,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Numpad1", KeyboardEvent.DOM_VK_NUMPAD1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad1,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Numpad1", KeyboardEvent.DOM_VK_NUMPAD1, "1", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad2,
+                   modifiers:{numericKeyPadKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Numpad2", KeyboardEvent.DOM_VK_NUMPAD2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad2,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Numpad2", KeyboardEvent.DOM_VK_NUMPAD2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad2,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Numpad2", KeyboardEvent.DOM_VK_NUMPAD2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad2,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Numpad2", KeyboardEvent.DOM_VK_NUMPAD2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad2,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Numpad2", KeyboardEvent.DOM_VK_NUMPAD2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad2,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Numpad2", KeyboardEvent.DOM_VK_NUMPAD2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad2,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Numpad2", KeyboardEvent.DOM_VK_NUMPAD2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad2,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Numpad2", KeyboardEvent.DOM_VK_NUMPAD2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad2,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Numpad2", KeyboardEvent.DOM_VK_NUMPAD2, "2", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad3,
+                   modifiers:{numericKeyPadKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Numpad3", KeyboardEvent.DOM_VK_NUMPAD3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad3,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Numpad3", KeyboardEvent.DOM_VK_NUMPAD3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad3,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Numpad3", KeyboardEvent.DOM_VK_NUMPAD3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad3,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Numpad3", KeyboardEvent.DOM_VK_NUMPAD3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad3,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Numpad3", KeyboardEvent.DOM_VK_NUMPAD3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad3,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Numpad3", KeyboardEvent.DOM_VK_NUMPAD3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad3,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Numpad3", KeyboardEvent.DOM_VK_NUMPAD3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad3,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Numpad3", KeyboardEvent.DOM_VK_NUMPAD3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad3,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Numpad3", KeyboardEvent.DOM_VK_NUMPAD3, "3", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad4,
+                   modifiers:{numericKeyPadKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Numpad4", KeyboardEvent.DOM_VK_NUMPAD4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad4,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Numpad4", KeyboardEvent.DOM_VK_NUMPAD4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad4,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Numpad4", KeyboardEvent.DOM_VK_NUMPAD4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad4,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Numpad4", KeyboardEvent.DOM_VK_NUMPAD4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad4,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Numpad4", KeyboardEvent.DOM_VK_NUMPAD4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad4,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Numpad4", KeyboardEvent.DOM_VK_NUMPAD4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad4,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Numpad4", KeyboardEvent.DOM_VK_NUMPAD4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad4,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Numpad4", KeyboardEvent.DOM_VK_NUMPAD4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad4,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Numpad4", KeyboardEvent.DOM_VK_NUMPAD4, "4", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad5,
+                   modifiers:{numericKeyPadKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Numpad5", KeyboardEvent.DOM_VK_NUMPAD5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad5,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Numpad5", KeyboardEvent.DOM_VK_NUMPAD5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad5,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Numpad5", KeyboardEvent.DOM_VK_NUMPAD5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad5,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Numpad5", KeyboardEvent.DOM_VK_NUMPAD5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad5,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Numpad5", KeyboardEvent.DOM_VK_NUMPAD5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad5,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Numpad5", KeyboardEvent.DOM_VK_NUMPAD5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad5,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Numpad5", KeyboardEvent.DOM_VK_NUMPAD5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad5,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Numpad5", KeyboardEvent.DOM_VK_NUMPAD5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad5,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Numpad5", KeyboardEvent.DOM_VK_NUMPAD5, "5", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad6,
+                   modifiers:{numericKeyPadKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Numpad6", KeyboardEvent.DOM_VK_NUMPAD6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad6,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Numpad6", KeyboardEvent.DOM_VK_NUMPAD6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad6,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Numpad6", KeyboardEvent.DOM_VK_NUMPAD6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad6,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Numpad6", KeyboardEvent.DOM_VK_NUMPAD6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad6,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Numpad6", KeyboardEvent.DOM_VK_NUMPAD6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad6,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Numpad6", KeyboardEvent.DOM_VK_NUMPAD6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad6,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Numpad6", KeyboardEvent.DOM_VK_NUMPAD6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad6,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Numpad6", KeyboardEvent.DOM_VK_NUMPAD6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad6,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Numpad6", KeyboardEvent.DOM_VK_NUMPAD6, "6", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad7,
+                   modifiers:{numericKeyPadKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Numpad7", KeyboardEvent.DOM_VK_NUMPAD7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad7,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Numpad7", KeyboardEvent.DOM_VK_NUMPAD7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad7,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Numpad7", KeyboardEvent.DOM_VK_NUMPAD7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad7,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Numpad7", KeyboardEvent.DOM_VK_NUMPAD7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad7,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Numpad7", KeyboardEvent.DOM_VK_NUMPAD7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad7,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Numpad7", KeyboardEvent.DOM_VK_NUMPAD7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad7,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Numpad7", KeyboardEvent.DOM_VK_NUMPAD7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad7,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Numpad7", KeyboardEvent.DOM_VK_NUMPAD7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad7,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Numpad7", KeyboardEvent.DOM_VK_NUMPAD7, "7", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad8,
+                   modifiers:{numericKeyPadKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Numpad8", KeyboardEvent.DOM_VK_NUMPAD8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad8,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Numpad8", KeyboardEvent.DOM_VK_NUMPAD8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad8,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Numpad8", KeyboardEvent.DOM_VK_NUMPAD8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad8,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Numpad8", KeyboardEvent.DOM_VK_NUMPAD8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad8,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Numpad8", KeyboardEvent.DOM_VK_NUMPAD8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad8,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Numpad8", KeyboardEvent.DOM_VK_NUMPAD8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad8,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Numpad8", KeyboardEvent.DOM_VK_NUMPAD8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad8,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Numpad8", KeyboardEvent.DOM_VK_NUMPAD8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad8,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Numpad8", KeyboardEvent.DOM_VK_NUMPAD8, "8", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad9,
+                   modifiers:{numericKeyPadKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Numpad9", KeyboardEvent.DOM_VK_NUMPAD9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad9,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Numpad9", KeyboardEvent.DOM_VK_NUMPAD9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad9,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Numpad9", KeyboardEvent.DOM_VK_NUMPAD9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad9,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Numpad9", KeyboardEvent.DOM_VK_NUMPAD9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad9,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Numpad9", KeyboardEvent.DOM_VK_NUMPAD9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad9,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Numpad9", KeyboardEvent.DOM_VK_NUMPAD9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad9,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Numpad9", KeyboardEvent.DOM_VK_NUMPAD9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad9,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Numpad9", KeyboardEvent.DOM_VK_NUMPAD9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad9,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Numpad9", KeyboardEvent.DOM_VK_NUMPAD9, "9", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad0,
+                   modifiers:{numericKeyPadKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Numpad0", KeyboardEvent.DOM_VK_NUMPAD0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad0,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Numpad0", KeyboardEvent.DOM_VK_NUMPAD0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad0,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Numpad0", KeyboardEvent.DOM_VK_NUMPAD0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad0,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Numpad0", KeyboardEvent.DOM_VK_NUMPAD0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad0,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Numpad0", KeyboardEvent.DOM_VK_NUMPAD0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad0,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Numpad0", KeyboardEvent.DOM_VK_NUMPAD0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad0,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Numpad0", KeyboardEvent.DOM_VK_NUMPAD0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad0,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Numpad0", KeyboardEvent.DOM_VK_NUMPAD0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Keypad0,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Numpad0", KeyboardEvent.DOM_VK_NUMPAD0, "0", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEquals,
+                   modifiers:{numericKeyPadKey:1}, chars:"=", unmodifiedChars:"="},
+                  "=", "NumpadEqual", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEquals,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"=", unmodifiedChars:"="},
+                  "=", "NumpadEqual", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEquals,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"=", unmodifiedChars:"="},
+                  "=", "NumpadEqual", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEquals,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"=", unmodifiedChars:"="},
+                  "=", "NumpadEqual", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEquals,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"=", unmodifiedChars:"="},
+                  "=", "NumpadEqual", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEquals,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"=", unmodifiedChars:"="},
+                  "=", "NumpadEqual", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEquals,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"=", unmodifiedChars:"="},
+                  "=", "NumpadEqual", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEquals,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"=", unmodifiedChars:"="},
+                  "=", "NumpadEqual", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEquals,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"=", unmodifiedChars:"="},
+                  "=", "NumpadEqual", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadDivide,
+                   modifiers:{numericKeyPadKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "/", "NumpadDivide", KeyboardEvent.DOM_VK_DIVIDE, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadDivide,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "/", "NumpadDivide", KeyboardEvent.DOM_VK_DIVIDE, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadDivide,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "/", "NumpadDivide", KeyboardEvent.DOM_VK_DIVIDE, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadDivide,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "/", "NumpadDivide", KeyboardEvent.DOM_VK_DIVIDE, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadDivide,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "/", "NumpadDivide", KeyboardEvent.DOM_VK_DIVIDE, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadDivide,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "/", "NumpadDivide", KeyboardEvent.DOM_VK_DIVIDE, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadDivide,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "/", "NumpadDivide", KeyboardEvent.DOM_VK_DIVIDE, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadDivide,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "/", "NumpadDivide", KeyboardEvent.DOM_VK_DIVIDE, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadDivide,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"/", unmodifiedChars:"/"},
+                  "/", "NumpadDivide", KeyboardEvent.DOM_VK_DIVIDE, "/", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMultiply,
+                   modifiers:{numericKeyPadKey:1}, chars:"*", unmodifiedChars:"*"},
+                  "*", "NumpadMultiply", KeyboardEvent.DOM_VK_MULTIPLY, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMultiply,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"*", unmodifiedChars:"*"},
+                  "*", "NumpadMultiply", KeyboardEvent.DOM_VK_MULTIPLY, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMultiply,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"*", unmodifiedChars:"*"},
+                  "*", "NumpadMultiply", KeyboardEvent.DOM_VK_MULTIPLY, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMultiply,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"*", unmodifiedChars:"*"},
+                  "*", "NumpadMultiply", KeyboardEvent.DOM_VK_MULTIPLY, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMultiply,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"*", unmodifiedChars:"*"},
+                  "*", "NumpadMultiply", KeyboardEvent.DOM_VK_MULTIPLY, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMultiply,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"*", unmodifiedChars:"*"},
+                  "*", "NumpadMultiply", KeyboardEvent.DOM_VK_MULTIPLY, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMultiply,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"*", unmodifiedChars:"*"},
+                  "*", "NumpadMultiply", KeyboardEvent.DOM_VK_MULTIPLY, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMultiply,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"*", unmodifiedChars:"*"},
+                  "*", "NumpadMultiply", KeyboardEvent.DOM_VK_MULTIPLY, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMultiply,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"*", unmodifiedChars:"*"},
+                  "*", "NumpadMultiply", KeyboardEvent.DOM_VK_MULTIPLY, "*", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMinus,
+                   modifiers:{numericKeyPadKey:1}, chars:"-", unmodifiedChars:"-"},
+                  "-", "NumpadSubtract", KeyboardEvent.DOM_VK_SUBTRACT, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMinus,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"-", unmodifiedChars:"-"},
+                  "-", "NumpadSubtract", KeyboardEvent.DOM_VK_SUBTRACT, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMinus,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"-", unmodifiedChars:"-"},
+                  "-", "NumpadSubtract", KeyboardEvent.DOM_VK_SUBTRACT, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMinus,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"-", unmodifiedChars:"-"},
+                  "-", "NumpadSubtract", KeyboardEvent.DOM_VK_SUBTRACT, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMinus,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"-", unmodifiedChars:"-"},
+                  "-", "NumpadSubtract", KeyboardEvent.DOM_VK_SUBTRACT, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMinus,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"-", unmodifiedChars:"-"},
+                  "-", "NumpadSubtract", KeyboardEvent.DOM_VK_SUBTRACT, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMinus,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"-", unmodifiedChars:"-"},
+                  "-", "NumpadSubtract", KeyboardEvent.DOM_VK_SUBTRACT, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMinus,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"-", unmodifiedChars:"-"},
+                  "-", "NumpadSubtract", KeyboardEvent.DOM_VK_SUBTRACT, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadMinus,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"-", unmodifiedChars:"-"},
+                  "-", "NumpadSubtract", KeyboardEvent.DOM_VK_SUBTRACT, "-", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadPlus,
+                   modifiers:{numericKeyPadKey:1}, chars:"+", unmodifiedChars:"+"},
+                  "+", "NumpadAdd", KeyboardEvent.DOM_VK_ADD, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadPlus,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"+", unmodifiedChars:"+"},
+                  "+", "NumpadAdd", KeyboardEvent.DOM_VK_ADD, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadPlus,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"+", unmodifiedChars:"+"},
+                  "+", "NumpadAdd", KeyboardEvent.DOM_VK_ADD, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadPlus,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"+", unmodifiedChars:"+"},
+                  "+", "NumpadAdd", KeyboardEvent.DOM_VK_ADD, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadPlus,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"+", unmodifiedChars:"+"},
+                  "+", "NumpadAdd", KeyboardEvent.DOM_VK_ADD, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadPlus,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"+", unmodifiedChars:"+"},
+                  "+", "NumpadAdd", KeyboardEvent.DOM_VK_ADD, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadPlus,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"+", unmodifiedChars:"+"},
+                  "+", "NumpadAdd", KeyboardEvent.DOM_VK_ADD, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadPlus,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"+", unmodifiedChars:"+"},
+                  "+", "NumpadAdd", KeyboardEvent.DOM_VK_ADD, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadPlus,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"+", unmodifiedChars:"+"},
+                  "+", "NumpadAdd", KeyboardEvent.DOM_VK_ADD, "+", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEnter,
+                   modifiers:{numericKeyPadKey:1}, chars:"\u0003", unmodifiedChars:"\u0003"},
+                  "Enter", "NumpadEnter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEnter,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:"\u0003", unmodifiedChars:"\u0003"},
+                  "Enter", "NumpadEnter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEnter,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:"\u0003", unmodifiedChars:"\u0003"},
+                  "Enter", "NumpadEnter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEnter,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0003", unmodifiedChars:"\u0003"},
+                  "Enter", "NumpadEnter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEnter,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:"\u0003", unmodifiedChars:"\u0003"},
+                  "Enter", "NumpadEnter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEnter,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:"\u0003", unmodifiedChars:"\u0003"},
+                  "Enter", "NumpadEnter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEnter,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:"\u0003", unmodifiedChars:"\u0003"},
+                  "Enter", "NumpadEnter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEnter,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u0003", unmodifiedChars:"\u0003"},
+                  "Enter", "NumpadEnter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_KeypadEnter,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:"\u0003", unmodifiedChars:"\u0003"},
+                  "Enter", "NumpadEnter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_JIS_KeypadComma,
+                   modifiers:{numericKeyPadKey:1, shiftKey:1}, chars:",", unmodifiedChars:","},
+                  ",", "NumpadComma", KeyboardEvent.DOM_VK_SEPARATOR, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_JIS_KeypadComma,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1}, chars:",", unmodifiedChars:","},
+                  ",", "NumpadComma", KeyboardEvent.DOM_VK_SEPARATOR, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_JIS_KeypadComma,
+                   modifiers:{numericKeyPadKey:1, ctrlKey:1, shiftKey:1}, chars:",", unmodifiedChars:","},
+                  ",", "NumpadComma", KeyboardEvent.DOM_VK_SEPARATOR, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_JIS_KeypadComma,
+                   modifiers:{numericKeyPadKey:1, altKey:1}, chars:",", unmodifiedChars:","},
+                  ",", "NumpadComma", KeyboardEvent.DOM_VK_SEPARATOR, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_JIS_KeypadComma,
+                   modifiers:{numericKeyPadKey:1, altKey:1, shiftKey:1}, chars:",", unmodifiedChars:","},
+                  ",", "NumpadComma", KeyboardEvent.DOM_VK_SEPARATOR, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_JIS_KeypadComma,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1}, chars:",", unmodifiedChars:","},
+                  ",", "NumpadComma", KeyboardEvent.DOM_VK_SEPARATOR, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_JIS_KeypadComma,
+                   modifiers:{numericKeyPadKey:1, altKey:1, ctrlKey:1, shiftKey:1}, chars:",", unmodifiedChars:","},
+                  ",", "NumpadComma", KeyboardEvent.DOM_VK_SEPARATOR, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_JIS_KeypadComma,
+                   modifiers:{numericKeyPadKey:1, metaKey:1}, chars:",", unmodifiedChars:","},
+                  ",", "NumpadComma", KeyboardEvent.DOM_VK_SEPARATOR, ",", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+
+    // French, numeric
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{}, chars:"&", unmodifiedChars:"&"},
+                  "&", "Digit1", KeyboardEvent.DOM_VK_1, "&", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{shiftKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{ctrlKey:1}, chars:"1", unmodifiedChars:"&"},
+                  "&", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{altKey:1}, chars:"\uF8FF", unmodifiedChars:"&"},
+                  "\uF8FF", "Digit1", KeyboardEvent.DOM_VK_1, "\uF8FF", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"", unmodifiedChars:"1"},
+                  "Dead", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"1", unmodifiedChars:"&"},
+                  "\uF8FF", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "Dead", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{metaKey:1}, chars:"&", unmodifiedChars:"&"},
+                  "&", "Digit1", KeyboardEvent.DOM_VK_1, "&", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{metaKey:1, shiftKey:1}, chars:"1", unmodifiedChars:"1"},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{}, chars:"\u00E9", unmodifiedChars:"\u00E9"},
+                  "\u00E9", "Digit2", KeyboardEvent.DOM_VK_2, "\u00E9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{shiftKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{ctrlKey:1}, chars:"2", unmodifiedChars:"\u00E9"},
+                  "\u00E9", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{altKey:1}, chars:"\u00EB", unmodifiedChars:"\u00E9"},
+                  "\u00EB", "Digit2", KeyboardEvent.DOM_VK_2, "\u00EB", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u201E", unmodifiedChars:"2"},
+                  "\u201E", "Digit2", KeyboardEvent.DOM_VK_2, "\u201E", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"2", unmodifiedChars:"\u00E9"},
+                  "\u00EB", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "\u201E", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{metaKey:1}, chars:"\u00E9", unmodifiedChars:"\u00E9"},
+                  "\u00E9", "Digit2", KeyboardEvent.DOM_VK_2, "\u00E9", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{metaKey:1, shiftKey:1}, chars:"2", unmodifiedChars:"2"},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{}, chars:"\"", unmodifiedChars:"\""},
+                  "\"", "Digit3", KeyboardEvent.DOM_VK_3, "\"", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{shiftKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{ctrlKey:1}, chars:"3", unmodifiedChars:"\""},
+                  "\"", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{altKey:1}, chars:"\u201C", unmodifiedChars:"\""},
+                  "\u201C", "Digit3", KeyboardEvent.DOM_VK_3, "\u201C", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u201D", unmodifiedChars:"3"},
+                  "\u201D", "Digit3", KeyboardEvent.DOM_VK_3, "\u201D", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"3", unmodifiedChars:"\""},
+                  "\u201C", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"3", unmodifiedChars:"3"},
+                  "\u201D", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{metaKey:1}, chars:"\"", unmodifiedChars:"\""},
+                  "\"", "Digit3", KeyboardEvent.DOM_VK_3, "\"", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // Cmd+Shift+3 is a shortcut key of taking a snapshot
+    // yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_3,
+    //                modifiers:{metaKey:1, shiftKey:1}, chars:"\"", unmodifiedChars:"\""},
+    //               "3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{}, chars:"'", unmodifiedChars:"'"},
+                  "'", "Digit4", KeyboardEvent.DOM_VK_4, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{shiftKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{ctrlKey:1}, chars:"4", unmodifiedChars:"'"},
+                  "'", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "4", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{altKey:1}, chars:"\u2018", unmodifiedChars:"'"},
+                  "\u2018", "Digit4", KeyboardEvent.DOM_VK_4, "\u2018", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u2019", unmodifiedChars:"4"},
+                  "\u2019", "Digit4", KeyboardEvent.DOM_VK_4, "\u2019", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"4", unmodifiedChars:"'"},
+                  "\u2018", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"4", unmodifiedChars:"4"},
+                  "\u2019", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{metaKey:1}, chars:"'", unmodifiedChars:"'"},
+                  "'", "Digit4", KeyboardEvent.DOM_VK_4, "'", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // Cmd+Shift+4 is a shortcut key of taking a snapshot in specific range
+    // yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_4,
+    //                modifiers:{metaKey:1, shiftKey:1}, chars:"4", unmodifiedChars:"4"},
+    //               "4", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{}, chars:"(", unmodifiedChars:"("},
+                  "(", "Digit5", KeyboardEvent.DOM_VK_5, "(", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{shiftKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{ctrlKey:1}, chars:"5", unmodifiedChars:"("},
+                  "(", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{altKey:1}, chars:"{", unmodifiedChars:"("},
+                  "{", "Digit5", KeyboardEvent.DOM_VK_5, "{", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"[", unmodifiedChars:"5"},
+                  "[", "Digit5", KeyboardEvent.DOM_VK_5, "[", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"5", unmodifiedChars:"("},
+                  "{", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "[", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{metaKey:1}, chars:"(", unmodifiedChars:"("},
+                  "(", "Digit5", KeyboardEvent.DOM_VK_5, "(", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{metaKey:1, shiftKey:1}, chars:"5", unmodifiedChars:"5"},
+                  "5", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{}, chars:"\u00A7", unmodifiedChars:"\u00A7"},
+                  "\u00A7", "Digit6", KeyboardEvent.DOM_VK_6, "\u00A7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{shiftKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Digit6", KeyboardEvent.DOM_VK_6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{ctrlKey:1}, chars:"\u001D", unmodifiedChars:"\u00A7"},
+                  "\u00A7", "Digit6", KeyboardEvent.DOM_VK_6, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u001D", unmodifiedChars:"6"},
+                  "6", "Digit6", KeyboardEvent.DOM_VK_6, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{altKey:1}, chars:"\u00B6", unmodifiedChars:"\u00A7"},
+                  "\u00B6", "Digit6", KeyboardEvent.DOM_VK_6, "\u00B6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00E5", unmodifiedChars:"6"},
+                  "\u00E5", "Digit6", KeyboardEvent.DOM_VK_6, "\u00E5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u001D", unmodifiedChars:"\u00A7"},
+                  "\u00B6", "Digit6", KeyboardEvent.DOM_VK_6, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u001D", unmodifiedChars:"6"},
+                  "\u00E5", "Digit6", KeyboardEvent.DOM_VK_6, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{metaKey:1}, chars:"\u00A7", unmodifiedChars:"\u00A7"},
+                  "\u00A7", "Digit6", KeyboardEvent.DOM_VK_6, "\u00A7", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{metaKey:1, shiftKey:1}, chars:"6", unmodifiedChars:"6"},
+                  "6", "Digit6", KeyboardEvent.DOM_VK_6, "6", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{}, chars:"\u00E8", unmodifiedChars:"\u00E8"},
+                  "\u00E8", "Digit7", KeyboardEvent.DOM_VK_7, "\u00E8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{shiftKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{ctrlKey:1}, chars:"7", unmodifiedChars:"\u00E8"},
+                  "\u00E8", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{altKey:1}, chars:"\u00AB", unmodifiedChars:"\u00E8"},
+                  "\u00AB", "Digit7", KeyboardEvent.DOM_VK_7, "\u00AB", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00BB", unmodifiedChars:"7"},
+                  "\u00BB", "Digit7", KeyboardEvent.DOM_VK_7, "\u00BB", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"7", unmodifiedChars:"\u00E8"},
+                  "\u00AB", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "\u00BB", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{metaKey:1}, chars:"\u00E8", unmodifiedChars:"\u00E8"},
+                  "\u00E8", "Digit7", KeyboardEvent.DOM_VK_7, "\u00E8", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{metaKey:1, shiftKey:1}, chars:"7", unmodifiedChars:"7"},
+                  "7", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{}, chars:"!", unmodifiedChars:"!"},
+                  "!", "Digit8", KeyboardEvent.DOM_VK_8, "!", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{shiftKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{ctrlKey:1}, chars:"8", unmodifiedChars:"!"},
+                  "!", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{altKey:1}, chars:"\u00A1", unmodifiedChars:"!"},
+                  "\u00A1", "Digit8", KeyboardEvent.DOM_VK_8, "\u00A1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00DB", unmodifiedChars:"8"},
+                  "\u00DB", "Digit8", KeyboardEvent.DOM_VK_8, "\u00DB", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"8", unmodifiedChars:"!"},
+                  "\u00A1", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "\u00DB", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{metaKey:1}, chars:"!", unmodifiedChars:"!"},
+                  "!", "Digit8", KeyboardEvent.DOM_VK_8, "!", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{metaKey:1, shiftKey:1}, chars:"8", unmodifiedChars:"8"},
+                  "8", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{}, chars:"\u00E7", unmodifiedChars:"\u00E7"},
+                  "\u00E7", "Digit9", KeyboardEvent.DOM_VK_9, "\u00E7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{shiftKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{ctrlKey:1}, chars:"\u001C", unmodifiedChars:"\u00E7"},
+                  "\u00E7", "Digit9", KeyboardEvent.DOM_VK_9, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u001C", unmodifiedChars:"9"},
+                  "9", "Digit9", KeyboardEvent.DOM_VK_9, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{altKey:1}, chars:"\u00C7", unmodifiedChars:"\u00E7"},
+                  "\u00C7", "Digit9", KeyboardEvent.DOM_VK_9, "\u00C7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00C1", unmodifiedChars:"9"},
+                  "\u00C1", "Digit9", KeyboardEvent.DOM_VK_9, "\u00C1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"\u001C", unmodifiedChars:"\u00E7"},
+                  "\u00C7", "Digit9", KeyboardEvent.DOM_VK_9, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"\u001C", unmodifiedChars:"9"},
+                  "\u00C1", "Digit9", KeyboardEvent.DOM_VK_9, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{metaKey:1}, chars:"\u00E7", unmodifiedChars:"\u00E7"},
+                  "\u00E7", "Digit9", KeyboardEvent.DOM_VK_9, "\u00E7", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{metaKey:1, shiftKey:1}, chars:"9", unmodifiedChars:"9"},
+                  "9", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{}, chars:"\u00E0", unmodifiedChars:"\u00E0"},
+                  "\u00E0", "Digit0", KeyboardEvent.DOM_VK_0, "\u00E0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{shiftKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{ctrlKey:1}, chars:"", unmodifiedChars:"\u00E0"},
+                  "\u00E0", "Digit0", KeyboardEvent.DOM_VK_0, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"", unmodifiedChars:"0"},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{altKey:1}, chars:"\u00F8", unmodifiedChars:"\u00E0"},
+                  "\u00F8", "Digit0", KeyboardEvent.DOM_VK_0, "\u00F8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00D8", unmodifiedChars:"0"},
+                  "\u00D8", "Digit0", KeyboardEvent.DOM_VK_0, "\u00D8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{altKey:1, ctrlKey:1}, chars:"", unmodifiedChars:"\u00E0"},
+                  "\u00F8", "Digit0", KeyboardEvent.DOM_VK_0, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:"", unmodifiedChars:"0"},
+                  "\u00D8", "Digit0", KeyboardEvent.DOM_VK_0, "\u0000" /* TODO */, SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{metaKey:1}, chars:"\u00E0", unmodifiedChars:"\u00E0"},
+                  "\u00E0", "Digit0", KeyboardEvent.DOM_VK_0, "\u00E0", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{metaKey:1, shiftKey:1}, chars:"0", unmodifiedChars:"0"},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Thai
+    // keycode should be DOM_VK_[A-Z] of the key on the latest ASCII capable keyboard layout is for alphabet
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{}, chars:"\u0E1F", unmodifiedChars:"\u0E1F"},
+                  "\u0E1F", "KeyA", KeyboardEvent.DOM_VK_A, "\u0E1F", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // keycode should be shifted character if unshifted character isn't an ASCII character
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_Quote,
+                   modifiers:{}, chars:"\u0E07", unmodifiedChars:"\u0E07"},
+                  "\u0E07", "Quote", KeyboardEvent.DOM_VK_PERIOD, "\u0E07", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // keycode should be same as ANSI keyboard layout's key which causes the native virtual keycode
+    // if the character of the key on the latest ASCII capable keyboard layout isn't for alphabet
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_Period,
+                   modifiers:{}, chars:"\u0E43", unmodifiedChars:"\u0E43"},
+                  "\u0E43", "Period", KeyboardEvent.DOM_VK_PERIOD, "\u0E43", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // keycode should be DOM_VK_[0-9] if the key on the latest ASCII capable keyboard layout is for numeric
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_1,
+                   modifiers:{}, chars:"\u0E45", unmodifiedChars:"\u0E45"},
+                  "\u0E45", "Digit1", KeyboardEvent.DOM_VK_1, "\u0E45", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_2,
+                   modifiers:{}, chars:"/", unmodifiedChars:"/"},
+                  "/", "Digit2", KeyboardEvent.DOM_VK_2, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_3,
+                   modifiers:{}, chars:"_", unmodifiedChars:"_"},
+                  "_", "Digit3", KeyboardEvent.DOM_VK_3, "_", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_4,
+                   modifiers:{}, chars:"\u0E20", unmodifiedChars:"\u0E20"},
+                  "\u0E20", "Digit4", KeyboardEvent.DOM_VK_4, "\u0E20", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_5,
+                   modifiers:{}, chars:"\u0E16", unmodifiedChars:"\u0E16"},
+                  "\u0E16", "Digit5", KeyboardEvent.DOM_VK_5, "\u0E16", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_6,
+                   modifiers:{}, chars:"\u0E38", unmodifiedChars:"\u0E38"},
+                  "\u0E38", "Digit6", KeyboardEvent.DOM_VK_6, "\u0E38", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_7,
+                   modifiers:{}, chars:"\u0E36", unmodifiedChars:"\u0E36"},
+                  "\u0E36", "Digit7", KeyboardEvent.DOM_VK_7, "\u0E36", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_8,
+                   modifiers:{}, chars:"\u0E04", unmodifiedChars:"\u0E04"},
+                  "\u0E04", "Digit8", KeyboardEvent.DOM_VK_8, "\u0E04", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_9,
+                   modifiers:{}, chars:"\u0E15", unmodifiedChars:"\u0E15"},
+                  "\u0E15", "Digit9", KeyboardEvent.DOM_VK_9, "\u0E15", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_THAI, keyCode:MAC_VK_ANSI_0,
+                   modifiers:{}, chars:"\u0E08", unmodifiedChars:"\u0E08"},
+                  "\u0E08", "Digit0", KeyboardEvent.DOM_VK_0, "\u0E08", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Dvorak-Qwerty, layout should be changed when Command key is pressed.
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{}, chars:"o", unmodifiedChars:"o"},
+                  "o", "KeyS", KeyboardEvent.DOM_VK_O, "o", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{shiftKey:1}, chars:"O", unmodifiedChars:"O"},
+                  "O", "KeyS", KeyboardEvent.DOM_VK_O, "O", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{ctrlKey:1}, chars:"\u000F", unmodifiedChars:"o"},
+                  "o", "KeyS", KeyboardEvent.DOM_VK_O, "o", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{altKey:1}, chars:"\u00F8", unmodifiedChars:"o"},
+                  "\u00F8", "KeyS", KeyboardEvent.DOM_VK_O, "\u00F8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_S,
+                   modifiers:{metaKey:1}, chars:"s", unmodifiedChars:"o"},
+                  "s", "KeyS", KeyboardEvent.DOM_VK_S, "s", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{}, chars:"e", unmodifiedChars:"e"},
+                  "e", "KeyD", KeyboardEvent.DOM_VK_E, "e", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{shiftKey:1}, chars:"E", unmodifiedChars:"E"},
+                  "E", "KeyD", KeyboardEvent.DOM_VK_E, "E", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{ctrlKey:1}, chars:"\u0005", unmodifiedChars:"e"},
+                  "e", "KeyD", KeyboardEvent.DOM_VK_E, "e", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{altKey:1}, chars:"", unmodifiedChars:"e"},
+                  "Dead", "KeyD", KeyboardEvent.DOM_VK_E, "\u00B4", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // dead key
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_D,
+                   modifiers:{metaKey:1}, chars:"d", unmodifiedChars:"e"},
+                  "d", "KeyD", KeyboardEvent.DOM_VK_D, "d", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_I,
+                   modifiers:{metaKey:1, altKey:1}, chars:"^", unmodifiedChars:"c"},
+                  "^", "KeyI", KeyboardEvent.DOM_VK_I, "^", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_DVORAK_QWERTY, keyCode:MAC_VK_ANSI_I,
+                   modifiers:{metaKey:1, altKey:1, shiftKey:1}, chars:"\u02C6", unmodifiedChars:"C"},
+                  "\u02C6", "KeyI", KeyboardEvent.DOM_VK_I, "\u02C6", SHOULD_DELIVER_KEYDOWN_KEYPRESS, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Arabic - PC keyboard layout inputs 2 or more characters with some key.
+    yield testKey({layout:KEYBOARD_LAYOUT_ARABIC_PC, keyCode:MAC_VK_ANSI_G,
+                   modifiers:{shiftKey:1}, chars:"\u0644\u0623", unmodifiedChars:"\u0644\u0623"},
+                  ["\u0644\u0623", "\u0644", "\u0623", "\u0644\u0623"], "KeyG", KeyboardEvent.DOM_VK_G, "\u0644\u0623", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_ARABIC_PC, keyCode:MAC_VK_ANSI_T,
+                   modifiers:{shiftKey:1}, chars:"\u0644\u0625", unmodifiedChars:"\u0644\u0625"},
+                  ["\u0644\u0625", "\u0644", "\u0625", "\u0644\u0625"], "KeyT", KeyboardEvent.DOM_VK_T, "\u0644\u0625", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_ARABIC_PC, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{shiftKey:1}, chars:"\u0644\u0622", unmodifiedChars:"\u0644\u0622"},
+                  ["\u0644\u0622", "\u0644", "\u0622", "\u0644\u0622"], "KeyB", KeyboardEvent.DOM_VK_B, "\u0644\u0622", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_ARABIC_PC, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{}, chars:"\u0644\u0627", unmodifiedChars:"\u0644\u0627"},
+                  ["\u0644\u0627", "\u0644", "\u0627", "\u0644\u0627"], "KeyB", KeyboardEvent.DOM_VK_B, "\u0644\u0627", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    cleanup();
+  }
+
+  function* testKeysOnWindows()
+  {
+    // On Windows, you can use Spy++ or Winspector (free) to watch window messages.
+    // The keyCode is given by the wParam of the last WM_KEYDOWN message. The
+    // chars string is given by the wParam of the WM_CHAR message. unmodifiedChars
+    // is not needed on Windows.
+
+    // Shift-ctrl-alt generates no WM_CHAR, but we still get a keypress
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:""},
+                  "A", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Greek plain text
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"\u03b1"},
+                  "\u03b1", "KeyA", KeyboardEvent.DOM_VK_A, "\u03b1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1}, chars:"\u0391"},
+                  "\u0391", "KeyA", KeyboardEvent.DOM_VK_A, "\u0391", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Greek ctrl keys produce Latin charcodes
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:WIN_VK_A,
+                   modifiers:{ctrlKey:1}, chars:"\u0001"},
+                  "\u03b1", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:WIN_VK_A,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0001"},
+                  "\u0391", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Caps Lock key event
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_CAPITAL,
+                   modifiers:{capsLockKey:1}, chars:""},
+                  "CapsLock", "CapsLock", KeyboardEvent.DOM_VK_CAPS_LOCK, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_CAPITAL,
+                   modifiers:{capsLockKey:0}, chars:""},
+                  "CapsLock", "CapsLock", KeyboardEvent.DOM_VK_CAPS_LOCK, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Shift keys
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_LSHIFT,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Shift", "ShiftLeft", KeyboardEvent.DOM_VK_SHIFT, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_RSHIFT,
+                   modifiers:{shiftRightKey:1}, chars:""},
+                  "Shift", "ShiftRight", KeyboardEvent.DOM_VK_SHIFT, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+
+    // Ctrl keys
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_LCONTROL,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "Control", "ControlLeft", KeyboardEvent.DOM_VK_CONTROL, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_RCONTROL,
+                   modifiers:{ctrlRightKey:1}, chars:""},
+                  "Control", "ControlRight", KeyboardEvent.DOM_VK_CONTROL, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+
+    // Alt keys
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_LMENU,
+                   modifiers:{altKey:1}, chars:""},
+                  "Alt", "AltLeft", KeyboardEvent.DOM_VK_ALT, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_RMENU,
+                   modifiers:{altRightKey:1}, chars:""},
+                  "Alt", "AltRight", KeyboardEvent.DOM_VK_ALT, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+
+    // Win keys
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_LWIN,
+                   modifiers:{metaKey:1}, chars:""},
+                  "Meta", "MetaLeft", KeyboardEvent.DOM_VK_WIN, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_LEFT);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_RWIN,
+                   modifiers:{metaRightKey:1}, chars:""},
+                  "Meta", "MetaRight", KeyboardEvent.DOM_VK_WIN, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_RIGHT);
+
+    // all keys on keyboard (keyCode test)
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_BACK,
+                   modifiers:{}, chars:"\u0008"},
+                  "Backspace", "Backspace", KeyboardEvent.DOM_VK_BACK_SPACE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_TAB,
+                   modifiers:{}, chars:"\t"},
+                  "Tab", "Tab", KeyboardEvent.DOM_VK_TAB, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_RETURN,
+                   modifiers:{}, chars:"\r"},
+                  "Enter", "Enter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_PAUSE,
+                   modifiers:{}, chars:""},
+                  "Pause", "Pause", KeyboardEvent.DOM_VK_PAUSE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_KANA,
+                   modifiers:{}, chars:""},
+                  "Unidentified", "", KeyboardEvent.DOM_VK_KANA, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_JUNJA,
+                   modifiers:{}, chars:""},
+                  "JunjaMode", "", KeyboardEvent.DOM_VK_JUNJA, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_FINAL,
+                   modifiers:{}, chars:""},
+                  "FinalMode", "", KeyboardEvent.DOM_VK_FINAL, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_KANJI,
+                   modifiers:{}, chars:""},
+                  "Unidentified", "", KeyboardEvent.DOM_VK_KANJI, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_ESCAPE,
+                   modifiers:{}, chars:""},
+                  "Escape", "Escape", KeyboardEvent.DOM_VK_ESCAPE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_CONVERT,
+                   modifiers:{}, chars:""},
+                  "Convert", "", KeyboardEvent.DOM_VK_CONVERT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NONCONVERT,
+                   modifiers:{}, chars:""},
+                  "NonConvert", "", KeyboardEvent.DOM_VK_NONCONVERT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_ACCEPT,
+                   modifiers:{}, chars:""},
+                  "Accept", "", KeyboardEvent.DOM_VK_ACCEPT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_MODECHANGE,
+                   modifiers:{}, chars:""},
+                  "ModeChange", "", KeyboardEvent.DOM_VK_MODECHANGE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_SPACE,
+                   modifiers:{}, chars:" "},
+                  " ", "Space", KeyboardEvent.DOM_VK_SPACE, " ", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // Ctrl+Space causes WM_CHAR with ' '.  However, its keypress event's ctrlKey state shouldn't be false.
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_SPACE,
+                   modifiers:{ctrlKey:1}, chars:" "},
+                  " ", "Space", KeyboardEvent.DOM_VK_SPACE, " ", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_SELECT,
+                   modifiers:{}, chars:""},
+                  "Select", "", KeyboardEvent.DOM_VK_SELECT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_PRINT,
+                   modifiers:{}, chars:""},
+                  "Unidentified", "", KeyboardEvent.DOM_VK_PRINT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_EXECUTE,
+                   modifiers:{}, chars:""},
+                  "Execute", "", KeyboardEvent.DOM_VK_EXECUTE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_SNAPSHOT,
+                   modifiers:{}, chars:""},
+                  "PrintScreen", "PrintScreen", KeyboardEvent.DOM_VK_PRINTSCREEN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_HELP,
+                   modifiers:{}, chars:""},
+                  "Help", "", KeyboardEvent.DOM_VK_HELP, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_SLEEP,
+                   modifiers:{}, chars:""},
+                  "Standby", "", KeyboardEvent.DOM_VK_SLEEP, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_PRIOR,
+                   modifiers:{}, chars:""},
+                  "PageUp", "PageUp", KeyboardEvent.DOM_VK_PAGE_UP, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NEXT,
+                   modifiers:{}, chars:""},
+                  "PageDown", "PageDown", KeyboardEvent.DOM_VK_PAGE_DOWN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_END,
+                   modifiers:{}, chars:""},
+                  "End", "End", KeyboardEvent.DOM_VK_END, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_HOME,
+                   modifiers:{}, chars:""},
+                  "Home", "Home", KeyboardEvent.DOM_VK_HOME, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_LEFT,
+                   modifiers:{}, chars:""},
+                  "ArrowLeft", "ArrowLeft", KeyboardEvent.DOM_VK_LEFT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_UP,
+                   modifiers:{}, chars:""},
+                  "ArrowUp", "ArrowUp", KeyboardEvent.DOM_VK_UP, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_RIGHT,
+                   modifiers:{}, chars:""},
+                  "ArrowRight", "ArrowRight", KeyboardEvent.DOM_VK_RIGHT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_DOWN,
+                   modifiers:{}, chars:""},
+                  "ArrowDown", "ArrowDown", KeyboardEvent.DOM_VK_DOWN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_INSERT,
+                   modifiers:{}, chars:""},
+                  "Insert", "Insert", KeyboardEvent.DOM_VK_INSERT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_DELETE,
+                   modifiers:{}, chars:""},
+                  "Delete", "Delete", KeyboardEvent.DOM_VK_DELETE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Backspace and Enter are handled with special path in mozilla::widget::NativeKey.  So, let's test them with modifiers too.
+    // Note that when both Ctrl and Alt are pressed, they don't cause WM_(SYS)CHAR message.
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_BACK,
+                   modifiers:{ctrlKey:1}, chars:"\u007F"},
+                  "Backspace", "Backspace", KeyboardEvent.DOM_VK_BACK_SPACE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_BACK,
+                   modifiers:{altKey:1}, chars:"\u0008"},
+                  "Backspace", "Backspace", KeyboardEvent.DOM_VK_BACK_SPACE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_BACK,
+                   modifiers:{ctrl:1, altKey:1}, chars:""},
+                  "Backspace", "Backspace", KeyboardEvent.DOM_VK_BACK_SPACE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_RETURN,
+                   modifiers:{ctrlKey:1}, chars:"\n"},
+                  "Enter", "Enter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_RETURN,
+                   modifiers:{altKey:1}, chars:"\r"},
+                  "Enter", "Enter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_RETURN,
+                   modifiers:{ctrl:1, altKey:1}, chars:""},
+                  "Enter", "Enter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Even non-printable key could be mapped as a printable key.
+    // Only "keyup" event cannot know if it *did* cause inputting text.
+    // Therefore, only "keydown" and "keypress" event's key value should be the character inputted by the key.
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_F4,
+                   modifiers:{}, chars:"a"},
+                  ["a", "a", "F4"], "F4", KeyboardEvent.DOM_VK_F4, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Even if key message is processed by IME, when the key causes inputting text,
+    // keypress event(s) should be fired.
+    const WIN_VK_PROCESSKEY_WITH_SC_A = WIN_VK_PROCESSKEY | 0x001E0000;
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_PROCESSKEY_WITH_SC_A,
+                   modifiers:{}, chars:"a"},
+                  ["a", "a", "Process"], "KeyA", KeyboardEvent.DOM_VK_PROCESSKEY, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_PROCESSKEY_WITH_SC_A,
+                   modifiers:{altKey:1}, chars:"a"},
+                  ["a", "a", "Process"], "KeyA", KeyboardEvent.DOM_VK_PROCESSKEY, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // US
+    // Alphabet
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"a"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1}, chars:"A"},
+                  "A", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{ctrlKey:1}, chars:"\u0001"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0001"},
+                  "A", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{altKey:1}, chars:"a"},
+                  "a", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"A"},
+                  "A", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_B,
+                   modifiers:{}, chars:"b"},
+                  "b", "KeyB", KeyboardEvent.DOM_VK_B, "b", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_B,
+                   modifiers:{shiftKey:1}, chars:"B"},
+                  "B", "KeyB", KeyboardEvent.DOM_VK_B, "B", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_B,
+                   modifiers:{ctrlKey:1}, chars:"\u0002"},
+                  "b", "KeyB", KeyboardEvent.DOM_VK_B, "b", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_B,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0002"},
+                  "B", "KeyB", KeyboardEvent.DOM_VK_B, "B", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_B,
+                   modifiers:{altKey:1}, chars:"b"},
+                  "b", "KeyB", KeyboardEvent.DOM_VK_B, "b", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_B,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"B"},
+                  "B", "KeyB", KeyboardEvent.DOM_VK_B, "B", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_C,
+                   modifiers:{}, chars:"c"},
+                  "c", "KeyC", KeyboardEvent.DOM_VK_C, "c", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_C,
+                   modifiers:{shiftKey:1}, chars:"C"},
+                  "C", "KeyC", KeyboardEvent.DOM_VK_C, "C", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_C,
+                   modifiers:{ctrlKey:1}, chars:"\u0003"},
+                  "c", "KeyC", KeyboardEvent.DOM_VK_C, "c", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_C,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0003"},
+                  "C", "KeyC", KeyboardEvent.DOM_VK_C, "C", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_C,
+                   modifiers:{altKey:1}, chars:"c"},
+                  "c", "KeyC", KeyboardEvent.DOM_VK_C, "c", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_C,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"C"},
+                  "C", "KeyC", KeyboardEvent.DOM_VK_C, "C", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_D,
+                   modifiers:{}, chars:"d"},
+                  "d", "KeyD", KeyboardEvent.DOM_VK_D, "d", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_D,
+                   modifiers:{shiftKey:1}, chars:"D"},
+                  "D", "KeyD", KeyboardEvent.DOM_VK_D, "D", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_D,
+                   modifiers:{ctrlKey:1}, chars:"\u0004"},
+                  "d", "KeyD", KeyboardEvent.DOM_VK_D, "d", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_D,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0004"},
+                  "D", "KeyD", KeyboardEvent.DOM_VK_D, "D", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_D,
+                   modifiers:{altKey:1}, chars:"d"},
+                  "d", "KeyD", KeyboardEvent.DOM_VK_D, "d", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_D,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"D"},
+                  "D", "KeyD", KeyboardEvent.DOM_VK_D, "D", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_E,
+                   modifiers:{}, chars:"e"},
+                  "e", "KeyE", KeyboardEvent.DOM_VK_E, "e", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_E,
+                   modifiers:{shiftKey:1}, chars:"E"},
+                  "E", "KeyE", KeyboardEvent.DOM_VK_E, "E", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_E,
+                   modifiers:{ctrlKey:1}, chars:"\u0005"},
+                  "e", "KeyE", KeyboardEvent.DOM_VK_E, "e", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_E,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0005"},
+                  "E", "KeyE", KeyboardEvent.DOM_VK_E, "E", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_E,
+                   modifiers:{altKey:1}, chars:"e"},
+                  "e", "KeyE", KeyboardEvent.DOM_VK_E, "e", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_E,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"E"},
+                  "E", "KeyE", KeyboardEvent.DOM_VK_E, "E", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_F,
+                   modifiers:{}, chars:"f"},
+                  "f", "KeyF", KeyboardEvent.DOM_VK_F, "f", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_F,
+                   modifiers:{shiftKey:1}, chars:"F"},
+                  "F", "KeyF", KeyboardEvent.DOM_VK_F, "F", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_F,
+                   modifiers:{ctrlKey:1}, chars:"\u0006"},
+                  "f", "KeyF", KeyboardEvent.DOM_VK_F, "f", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_F,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0006"},
+                  "F", "KeyF", KeyboardEvent.DOM_VK_F, "F", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_F,
+                   modifiers:{altKey:1}, chars:"f"},
+                  "f", "KeyF", KeyboardEvent.DOM_VK_F, "f", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_F,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"F"},
+                  "F", "KeyF", KeyboardEvent.DOM_VK_F, "F", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_G,
+                   modifiers:{}, chars:"g"},
+                  "g", "KeyG", KeyboardEvent.DOM_VK_G, "g", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_G,
+                   modifiers:{shiftKey:1}, chars:"G"},
+                  "G", "KeyG", KeyboardEvent.DOM_VK_G, "G", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_G,
+                   modifiers:{ctrlKey:1}, chars:"\u0007"},
+                  "g", "KeyG", KeyboardEvent.DOM_VK_G, "g", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_G,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0007"},
+                  "G", "KeyG", KeyboardEvent.DOM_VK_G, "G", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_G,
+                   modifiers:{altKey:1}, chars:"g"},
+                  "g", "KeyG", KeyboardEvent.DOM_VK_G, "g", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_G,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"G"},
+                  "G", "KeyG", KeyboardEvent.DOM_VK_G, "G", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_H,
+                   modifiers:{}, chars:"h"},
+                  "h", "KeyH", KeyboardEvent.DOM_VK_H, "h", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_H,
+                   modifiers:{shiftKey:1}, chars:"H"},
+                  "H", "KeyH", KeyboardEvent.DOM_VK_H, "H", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_H,
+                   modifiers:{ctrlKey:1}, chars:"\u0008"},
+                  "h", "KeyH", KeyboardEvent.DOM_VK_H, "h", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_H,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0008"},
+                  "H", "KeyH", KeyboardEvent.DOM_VK_H, "H", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_H,
+                   modifiers:{altKey:1}, chars:"h"},
+                  "h", "KeyH", KeyboardEvent.DOM_VK_H, "h", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_H,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"H"},
+                  "H", "KeyH", KeyboardEvent.DOM_VK_H, "H", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_I,
+                   modifiers:{}, chars:"i"},
+                  "i", "KeyI", KeyboardEvent.DOM_VK_I, "i", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_I,
+                   modifiers:{shiftKey:1}, chars:"I"},
+                  "I", "KeyI", KeyboardEvent.DOM_VK_I, "I", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_I,
+                   modifiers:{ctrlKey:1}, chars:"\u0009"},
+                  "i", "KeyI", KeyboardEvent.DOM_VK_I, "i", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_I,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0009"},
+                  "I", "KeyI", KeyboardEvent.DOM_VK_I, "I", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_I,
+                   modifiers:{altKey:1}, chars:"i"},
+                  "i", "KeyI", KeyboardEvent.DOM_VK_I, "i", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_I,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"I"},
+                  "I", "KeyI", KeyboardEvent.DOM_VK_I, "I", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_J,
+                   modifiers:{}, chars:"j"},
+                  "j", "KeyJ", KeyboardEvent.DOM_VK_J, "j", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_J,
+                   modifiers:{shiftKey:1}, chars:"J"},
+                  "J", "KeyJ", KeyboardEvent.DOM_VK_J, "J", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_J,
+                   modifiers:{ctrlKey:1}, chars:"\u000A"},
+                  "j", "KeyJ", KeyboardEvent.DOM_VK_J, "j", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_J,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000A"},
+                  "J", "KeyJ", KeyboardEvent.DOM_VK_J, "J", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_J,
+                   modifiers:{altKey:1}, chars:"j"},
+                  "j", "KeyJ", KeyboardEvent.DOM_VK_J, "j", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_J,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"J"},
+                  "J", "KeyJ", KeyboardEvent.DOM_VK_J, "J", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_K,
+                   modifiers:{}, chars:"k"},
+                  "k", "KeyK", KeyboardEvent.DOM_VK_K, "k", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_K,
+                   modifiers:{shiftKey:1}, chars:"K"},
+                  "K", "KeyK", KeyboardEvent.DOM_VK_K, "K", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_K,
+                   modifiers:{ctrlKey:1}, chars:"\u000B"},
+                  "k", "KeyK", KeyboardEvent.DOM_VK_K, "k", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_K,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000B"},
+                  "K", "KeyK", KeyboardEvent.DOM_VK_K, "K", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_K,
+                   modifiers:{altKey:1}, chars:"k"},
+                  "k", "KeyK", KeyboardEvent.DOM_VK_K, "k", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_K,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"K"},
+                  "K", "KeyK", KeyboardEvent.DOM_VK_K, "K", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_L,
+                   modifiers:{}, chars:"l"},
+                  "l", "KeyL", KeyboardEvent.DOM_VK_L, "l", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_L,
+                   modifiers:{shiftKey:1}, chars:"L"},
+                  "L", "KeyL", KeyboardEvent.DOM_VK_L, "L", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_L,
+                   modifiers:{ctrlKey:1}, chars:"\u000C"},
+                  "l", "KeyL", KeyboardEvent.DOM_VK_L, "l", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_L,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000C"},
+                  "L", "KeyL", KeyboardEvent.DOM_VK_L, "L", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_L,
+                   modifiers:{altKey:1}, chars:"l"},
+                  "l", "KeyL", KeyboardEvent.DOM_VK_L, "l", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_L,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"L"},
+                  "L", "KeyL", KeyboardEvent.DOM_VK_L, "L", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_M,
+                   modifiers:{}, chars:"m"},
+                  "m", "KeyM", KeyboardEvent.DOM_VK_M, "m", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_M,
+                   modifiers:{shiftKey:1}, chars:"M"},
+                  "M", "KeyM", KeyboardEvent.DOM_VK_M, "M", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_M,
+                   modifiers:{ctrlKey:1}, chars:"\u000D"},
+                  "m", "KeyM", KeyboardEvent.DOM_VK_M, "m", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_M,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000D"},
+                  "M", "KeyM", KeyboardEvent.DOM_VK_M, "M", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_M,
+                   modifiers:{altKey:1}, chars:"m"},
+                  "m", "KeyM", KeyboardEvent.DOM_VK_M, "m", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_M,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"M"},
+                  "M", "KeyM", KeyboardEvent.DOM_VK_M, "M", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_N,
+                   modifiers:{}, chars:"n"},
+                  "n", "KeyN", KeyboardEvent.DOM_VK_N, "n", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_N,
+                   modifiers:{shiftKey:1}, chars:"N"},
+                  "N", "KeyN", KeyboardEvent.DOM_VK_N, "N", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_N,
+                   modifiers:{ctrlKey:1}, chars:"\u000E"},
+                  "n", "KeyN", KeyboardEvent.DOM_VK_N, "n", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_N,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000E"},
+                  "N", "KeyN", KeyboardEvent.DOM_VK_N, "N", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_N,
+                   modifiers:{altKey:1}, chars:"n"},
+                  "n", "KeyN", KeyboardEvent.DOM_VK_N, "n", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_N,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"N"},
+                  "N", "KeyN", KeyboardEvent.DOM_VK_N, "N", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_O,
+                   modifiers:{}, chars:"o"},
+                  "o", "KeyO", KeyboardEvent.DOM_VK_O, "o", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_O,
+                   modifiers:{shiftKey:1}, chars:"O"},
+                  "O", "KeyO", KeyboardEvent.DOM_VK_O, "O", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_O,
+                   modifiers:{ctrlKey:1}, chars:"\u000F"},
+                  "o", "KeyO", KeyboardEvent.DOM_VK_O, "o", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_O,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u000F"},
+                  "O", "KeyO", KeyboardEvent.DOM_VK_O, "O", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_O,
+                   modifiers:{altKey:1}, chars:"o"},
+                  "o", "KeyO", KeyboardEvent.DOM_VK_O, "o", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_O,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"O"},
+                  "O", "KeyO", KeyboardEvent.DOM_VK_O, "O", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_P,
+                   modifiers:{}, chars:"p"},
+                  "p", "KeyP", KeyboardEvent.DOM_VK_P, "p", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_P,
+                   modifiers:{shiftKey:1}, chars:"P"},
+                  "P", "KeyP", KeyboardEvent.DOM_VK_P, "P", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_P,
+                   modifiers:{ctrlKey:1}, chars:"\u0010"},
+                  "p", "KeyP", KeyboardEvent.DOM_VK_P, "p", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_P,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0010"},
+                  "P", "KeyP", KeyboardEvent.DOM_VK_P, "P", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_P,
+                   modifiers:{altKey:1}, chars:"p"},
+                  "p", "KeyP", KeyboardEvent.DOM_VK_P, "p", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_P,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"P"},
+                  "P", "KeyP", KeyboardEvent.DOM_VK_P, "P", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Q,
+                   modifiers:{}, chars:"q"},
+                  "q", "KeyQ", KeyboardEvent.DOM_VK_Q, "q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Q,
+                   modifiers:{shiftKey:1}, chars:"Q"},
+                  "Q", "KeyQ", KeyboardEvent.DOM_VK_Q, "Q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Q,
+                   modifiers:{ctrlKey:1}, chars:"\u0011"},
+                  "q", "KeyQ", KeyboardEvent.DOM_VK_Q, "q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Q,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0011"},
+                  "Q", "KeyQ", KeyboardEvent.DOM_VK_Q, "Q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Q,
+                   modifiers:{altKey:1}, chars:"q"},
+                  "q", "KeyQ", KeyboardEvent.DOM_VK_Q, "q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Q,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"Q"},
+                  "Q", "KeyQ", KeyboardEvent.DOM_VK_Q, "Q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_R,
+                   modifiers:{}, chars:"r"},
+                  "r", "KeyR", KeyboardEvent.DOM_VK_R, "r", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_R,
+                   modifiers:{shiftKey:1}, chars:"R"},
+                  "R", "KeyR", KeyboardEvent.DOM_VK_R, "R", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_R,
+                   modifiers:{ctrlKey:1}, chars:"\u0012"},
+                  "r", "KeyR", KeyboardEvent.DOM_VK_R, "r", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_R,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0012"},
+                  "R", "KeyR", KeyboardEvent.DOM_VK_R, "R", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_R,
+                   modifiers:{altKey:1}, chars:"r"},
+                  "r", "KeyR", KeyboardEvent.DOM_VK_R, "r", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_R,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"R"},
+                  "R", "KeyR", KeyboardEvent.DOM_VK_R, "R", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_S,
+                   modifiers:{}, chars:"s"},
+                  "s", "KeyS", KeyboardEvent.DOM_VK_S, "s", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_S,
+                   modifiers:{shiftKey:1}, chars:"S"},
+                  "S", "KeyS", KeyboardEvent.DOM_VK_S, "S", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_S,
+                   modifiers:{ctrlKey:1}, chars:"\u0013"},
+                  "s", "KeyS", KeyboardEvent.DOM_VK_S, "s", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_S,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0013"},
+                  "S", "KeyS", KeyboardEvent.DOM_VK_S, "S", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_S,
+                   modifiers:{altKey:1}, chars:"s"},
+                  "s", "KeyS", KeyboardEvent.DOM_VK_S, "s", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_S,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"S"},
+                  "S", "KeyS", KeyboardEvent.DOM_VK_S, "S", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_T,
+                   modifiers:{}, chars:"t"},
+                  "t", "KeyT", KeyboardEvent.DOM_VK_T, "t", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_T,
+                   modifiers:{shiftKey:1}, chars:"T"},
+                  "T", "KeyT", KeyboardEvent.DOM_VK_T, "T", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_T,
+                   modifiers:{ctrlKey:1}, chars:"\u0014"},
+                  "t", "KeyT", KeyboardEvent.DOM_VK_T, "t", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_T,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0014"},
+                  "T", "KeyT", KeyboardEvent.DOM_VK_T, "T", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_T,
+                   modifiers:{altKey:1}, chars:"t"},
+                  "t", "KeyT", KeyboardEvent.DOM_VK_T, "t", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_T,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"T"},
+                  "T", "KeyT", KeyboardEvent.DOM_VK_T, "T", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_U,
+                   modifiers:{}, chars:"u"},
+                  "u", "KeyU", KeyboardEvent.DOM_VK_U, "u", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_U,
+                   modifiers:{shiftKey:1}, chars:"U"},
+                  "U", "KeyU", KeyboardEvent.DOM_VK_U, "U", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_U,
+                   modifiers:{ctrlKey:1}, chars:"\u0015"},
+                  "u", "KeyU", KeyboardEvent.DOM_VK_U, "u", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_U,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0015"},
+                  "U", "KeyU", KeyboardEvent.DOM_VK_U, "U", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_U,
+                   modifiers:{altKey:1}, chars:"u"},
+                  "u", "KeyU", KeyboardEvent.DOM_VK_U, "u", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_U,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"U"},
+                  "U", "KeyU", KeyboardEvent.DOM_VK_U, "U", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_V,
+                   modifiers:{}, chars:"v"},
+                  "v", "KeyV", KeyboardEvent.DOM_VK_V, "v", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_V,
+                   modifiers:{shiftKey:1}, chars:"V"},
+                  "V", "KeyV", KeyboardEvent.DOM_VK_V, "V", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_V,
+                   modifiers:{ctrlKey:1}, chars:"\u0016"},
+                  "v", "KeyV", KeyboardEvent.DOM_VK_V, "v", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_V,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0016"},
+                  "V", "KeyV", KeyboardEvent.DOM_VK_V, "V", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_V,
+                   modifiers:{altKey:1}, chars:"v"},
+                  "v", "KeyV", KeyboardEvent.DOM_VK_V, "v", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_V,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"V"},
+                  "V", "KeyV", KeyboardEvent.DOM_VK_V, "V", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_W,
+                   modifiers:{}, chars:"w"},
+                  "w", "KeyW", KeyboardEvent.DOM_VK_W, "w", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_W,
+                   modifiers:{shiftKey:1}, chars:"W"},
+                  "W", "KeyW", KeyboardEvent.DOM_VK_W, "W", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_W,
+                   modifiers:{ctrlKey:1}, chars:"\u0017"},
+                  "w", "KeyW", KeyboardEvent.DOM_VK_W, "w", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_W,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0017"},
+                  "W", "KeyW", KeyboardEvent.DOM_VK_W, "W", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_W,
+                   modifiers:{altKey:1}, chars:"w"},
+                  "w", "KeyW", KeyboardEvent.DOM_VK_W, "w", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_W,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"W"},
+                  "W", "KeyW", KeyboardEvent.DOM_VK_W, "W", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_X,
+                   modifiers:{}, chars:"x"},
+                  "x", "KeyX", KeyboardEvent.DOM_VK_X, "x", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_X,
+                   modifiers:{shiftKey:1}, chars:"X"},
+                  "X", "KeyX", KeyboardEvent.DOM_VK_X, "X", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_X,
+                   modifiers:{ctrlKey:1}, chars:"\u0018"},
+                  "x", "KeyX", KeyboardEvent.DOM_VK_X, "x", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_X,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0018"},
+                  "X", "KeyX", KeyboardEvent.DOM_VK_X, "X", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_X,
+                   modifiers:{altKey:1}, chars:"x"},
+                  "x", "KeyX", KeyboardEvent.DOM_VK_X, "x", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_X,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"X"},
+                  "X", "KeyX", KeyboardEvent.DOM_VK_X, "X", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Y,
+                   modifiers:{}, chars:"y"},
+                  "y", "KeyY", KeyboardEvent.DOM_VK_Y, "y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Y,
+                   modifiers:{shiftKey:1}, chars:"Y"},
+                  "Y", "KeyY", KeyboardEvent.DOM_VK_Y, "Y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Y,
+                   modifiers:{ctrlKey:1}, chars:"\u0019"},
+                  "y", "KeyY", KeyboardEvent.DOM_VK_Y, "y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Y,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0019"},
+                  "Y", "KeyY", KeyboardEvent.DOM_VK_Y, "Y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Y,
+                   modifiers:{altKey:1}, chars:"y"},
+                  "y", "KeyY", KeyboardEvent.DOM_VK_Y, "y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Y,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"Y"},
+                  "Y", "KeyY", KeyboardEvent.DOM_VK_Y, "Y", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Z,
+                   modifiers:{}, chars:"z"},
+                  "z", "KeyZ", KeyboardEvent.DOM_VK_Z, "z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Z,
+                   modifiers:{shiftKey:1}, chars:"Z"},
+                  "Z", "KeyZ", KeyboardEvent.DOM_VK_Z, "Z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Z,
+                   modifiers:{ctrlKey:1}, chars:"\u001A"},
+                  "z", "KeyZ", KeyboardEvent.DOM_VK_Z, "z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Z,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u001A"},
+                  "Z", "KeyZ", KeyboardEvent.DOM_VK_Z, "Z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Z,
+                   modifiers:{altKey:1}, chars:"z"},
+                  "z", "KeyZ", KeyboardEvent.DOM_VK_Z, "z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_Z,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"Z"},
+                  "Z", "KeyZ", KeyboardEvent.DOM_VK_Z, "Z", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Numeric
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_0,
+                   modifiers:{}, chars:"0"},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_0,
+                   modifiers:{shiftKey:1}, chars:")"},
+                  ")", "Digit0", KeyboardEvent.DOM_VK_0, ")", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_0,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_0,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  ")", "Digit0", KeyboardEvent.DOM_VK_0, ")", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_0,
+                   modifiers:{altKey:1}, chars:"0"},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_0,
+                   modifiers:{altKey:1, shiftKey:1}, chars:")"},
+                  ")", "Digit0", KeyboardEvent.DOM_VK_0, ")", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_1,
+                   modifiers:{}, chars:"1"},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_1,
+                   modifiers:{shiftKey:1}, chars:"!"},
+                  "!", "Digit1", KeyboardEvent.DOM_VK_1, "!", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_1,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_1,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "!", "Digit1", KeyboardEvent.DOM_VK_1, "!", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_1,
+                   modifiers:{altKey:1}, chars:"1"},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_1,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"!"},
+                  "!", "Digit1", KeyboardEvent.DOM_VK_1, "!", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_2,
+                   modifiers:{}, chars:"2"},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_2,
+                   modifiers:{shiftKey:1}, chars:"@"},
+                  "@", "Digit2", KeyboardEvent.DOM_VK_2, "@", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_2,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_2,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "@", "Digit2", KeyboardEvent.DOM_VK_2, "@", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_2,
+                   modifiers:{altKey:1}, chars:"2"},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_2,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"@"},
+                  "@", "Digit2", KeyboardEvent.DOM_VK_2, "@", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_3,
+                   modifiers:{}, chars:"3"},
+                  "3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_3,
+                   modifiers:{shiftKey:1}, chars:"#"},
+                  "#", "Digit3", KeyboardEvent.DOM_VK_3, "#", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_3,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_3,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "#", "Digit3", KeyboardEvent.DOM_VK_3, "#", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_3,
+                   modifiers:{altKey:1}, chars:"3"},
+                  "3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_3,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"#"},
+                  "#", "Digit3", KeyboardEvent.DOM_VK_3, "#", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_4,
+                   modifiers:{}, chars:"4"},
+                  "4", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_4,
+                   modifiers:{shiftKey:1}, chars:"$"},
+                  "$", "Digit4", KeyboardEvent.DOM_VK_4, "$", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_4,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "4", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_4,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "$", "Digit4", KeyboardEvent.DOM_VK_4, "$", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_4,
+                   modifiers:{altKey:1}, chars:"4"},
+                  "4", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_4,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"$"},
+                  "$", "Digit4", KeyboardEvent.DOM_VK_4, "$", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_5,
+                   modifiers:{}, chars:"5"},
+                  "5", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_5,
+                   modifiers:{shiftKey:1}, chars:"%"},
+                  "%", "Digit5", KeyboardEvent.DOM_VK_5, "%", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_5,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "5", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_5,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "%", "Digit5", KeyboardEvent.DOM_VK_5, "%", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_5,
+                   modifiers:{altKey:1}, chars:"5"},
+                  "5", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_5,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"%"},
+                  "%", "Digit5", KeyboardEvent.DOM_VK_5, "%", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_6,
+                   modifiers:{}, chars:"6"},
+                  "6", "Digit6", KeyboardEvent.DOM_VK_6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_6,
+                   modifiers:{shiftKey:1}, chars:"^"},
+                  "^", "Digit6", KeyboardEvent.DOM_VK_6, "^", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_6,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "6", "Digit6", KeyboardEvent.DOM_VK_6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_6,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u001E"},
+                  "^", "Digit6", KeyboardEvent.DOM_VK_6, "^", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_6,
+                   modifiers:{altKey:1}, chars:"6"},
+                  "6", "Digit6", KeyboardEvent.DOM_VK_6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_6,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"^"},
+                  "^", "Digit6", KeyboardEvent.DOM_VK_6, "^", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_7,
+                   modifiers:{}, chars:"7"},
+                  "7", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_7,
+                   modifiers:{shiftKey:1}, chars:"&"},
+                  "&", "Digit7", KeyboardEvent.DOM_VK_7, "&", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_7,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "7", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_7,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "&", "Digit7", KeyboardEvent.DOM_VK_7, "&", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_7,
+                   modifiers:{altKey:1}, chars:"7"},
+                  "7", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_7,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"&"},
+                  "&", "Digit7", KeyboardEvent.DOM_VK_7, "&", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_8,
+                   modifiers:{}, chars:"8"},
+                  "8", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_8,
+                   modifiers:{shiftKey:1}, chars:"*"},
+                  "*", "Digit8", KeyboardEvent.DOM_VK_8, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_8,
+                   modifiers:{ctrlKey:1, }, chars:""},
+                  "8", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_8,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "*", "Digit8", KeyboardEvent.DOM_VK_8, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_8,
+                   modifiers:{altKey:1}, chars:"8"},
+                  "8", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_8,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"*"},
+                  "*", "Digit8", KeyboardEvent.DOM_VK_8, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_9,
+                   modifiers:{}, chars:"9"},
+                  "9", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_9,
+                   modifiers:{shiftKey:1}, chars:"("},
+                  "(", "Digit9", KeyboardEvent.DOM_VK_9, "(", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_9,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "9", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_9,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "(", "Digit9", KeyboardEvent.DOM_VK_9, "(", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_9,
+                   modifiers:{altKey:1}, chars:"9"},
+                  "9", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_9,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"("},
+                  "(", "Digit9", KeyboardEvent.DOM_VK_9, "(", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // OEM keys
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_MINUS,
+                   modifiers:{}, chars:"-"},
+                  "-", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_MINUS,
+                   modifiers:{shiftKey:1}, chars:"_"},
+                  "_", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "_", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_MINUS,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "-", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_MINUS,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u001F"},
+                  "_", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "_", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_MINUS,
+                   modifiers:{altKey:1}, chars:"-"},
+                  "-", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_MINUS,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"_"},
+                  "_", "Minus", KeyboardEvent.DOM_VK_HYPHEN_MINUS, "_", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PLUS,
+                   modifiers:{}, chars:"="},
+                  "=", "Equal", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PLUS,
+                   modifiers:{shiftKey:1}, chars:"+"},
+                  "+", "Equal", KeyboardEvent.DOM_VK_EQUALS, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PLUS,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "=", "Equal", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PLUS,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "+", "Equal", KeyboardEvent.DOM_VK_EQUALS, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PLUS,
+                   modifiers:{altKey:1}, chars:"="},
+                  "=", "Equal", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PLUS,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"+"},
+                  "+", "Equal", KeyboardEvent.DOM_VK_EQUALS, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_4,
+                   modifiers:{}, chars:"["},
+                  "[", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "[", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_4,
+                   modifiers:{shiftKey:1}, chars:"{"},
+                  "{", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "{", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_4,
+                   modifiers:{ctrlKey:1}, chars:"\u001B"},
+                  "[", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "[", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_4,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "{", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "{", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_4,
+                   modifiers:{altKey:1}, chars:"["},
+                  "[", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "[", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_4,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"{"},
+                  "{", "BracketLeft", KeyboardEvent.DOM_VK_OPEN_BRACKET, "{", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_6,
+                   modifiers:{}, chars:"]"},
+                  "]", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "]", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_6,
+                   modifiers:{shiftKey:1}, chars:"}"},
+                  "}", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "}", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_6,
+                   modifiers:{ctrlKey:1}, chars:"\u001D"},
+                  "]", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "]", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_6,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "}", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "}", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_6,
+                   modifiers:{altKey:1}, chars:"]"},
+                  "]", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "]", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_6,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"}"},
+                  "}", "BracketRight", KeyboardEvent.DOM_VK_CLOSE_BRACKET, "}", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_1,
+                   modifiers:{}, chars:";"},
+                  ";", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ";", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_1,
+                   modifiers:{shiftKey:1}, chars:":"},
+                  ":", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ":", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_1,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  ";", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ";", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_1,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  ":", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ":", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1}, chars:";"},
+                  ";", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ";", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1, shiftKey:1}, chars:":"},
+                  ":", "Semicolon", KeyboardEvent.DOM_VK_SEMICOLON, ":", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_7,
+                   modifiers:{}, chars:"'"},
+                  "'", "Quote", KeyboardEvent.DOM_VK_QUOTE, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_7,
+                   modifiers:{shiftKey:1}, chars:"\""},
+                  "\"", "Quote", KeyboardEvent.DOM_VK_QUOTE, "\"", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_7,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "'", "Quote", KeyboardEvent.DOM_VK_QUOTE, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_7,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "\"", "Quote", KeyboardEvent.DOM_VK_QUOTE, "\"", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_7,
+                   modifiers:{altKey:1}, chars:"'"},
+                  "'", "Quote", KeyboardEvent.DOM_VK_QUOTE, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_7,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\""},
+                  "\"", "Quote", KeyboardEvent.DOM_VK_QUOTE, "\"", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_5,
+                   modifiers:{}, chars:"\\"},
+                  "\\", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "\\", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_5,
+                   modifiers:{shiftKey:1}, chars:"|"},
+                  "|", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "|", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_5,
+                   modifiers:{ctrlKey:1}, chars:"\u001C"},
+                  "\\", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "\\", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_5,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "|", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "|", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_5,
+                   modifiers:{altKey:1}, chars:"\\"},
+                  "\\", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "\\", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_5,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"|"},
+                  "|", "Backslash", KeyboardEvent.DOM_VK_BACK_SLASH, "|", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_COMMA,
+                   modifiers:{}, chars:","},
+                  ",", "Comma", KeyboardEvent.DOM_VK_COMMA, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_COMMA,
+                   modifiers:{shiftKey:1}, chars:"<"},
+                  "<", "Comma", KeyboardEvent.DOM_VK_COMMA, "<", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_COMMA,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  ",", "Comma", KeyboardEvent.DOM_VK_COMMA, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_COMMA,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "<", "Comma", KeyboardEvent.DOM_VK_COMMA, "<", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_COMMA,
+                   modifiers:{altKey:1}, chars:","},
+                  ",", "Comma", KeyboardEvent.DOM_VK_COMMA, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_COMMA,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"<"},
+                  "<", "Comma", KeyboardEvent.DOM_VK_COMMA, "<", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PERIOD,
+                   modifiers:{}, chars:"."},
+                  ".", "Period", KeyboardEvent.DOM_VK_PERIOD, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PERIOD,
+                   modifiers:{shiftKey:1}, chars:">"},
+                  ">", "Period", KeyboardEvent.DOM_VK_PERIOD, ">", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PERIOD,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  ".", "Period", KeyboardEvent.DOM_VK_PERIOD, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PERIOD,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  ">", "Period", KeyboardEvent.DOM_VK_PERIOD, ">", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PERIOD,
+                   modifiers:{altKey:1}, chars:"."},
+                  ".", "Period", KeyboardEvent.DOM_VK_PERIOD, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PERIOD,
+                   modifiers:{altKey:1, shiftKey:1}, chars:">"},
+                  ">", "Period", KeyboardEvent.DOM_VK_PERIOD, ">", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_2,
+                   modifiers:{}, chars:"/"},
+                  "/", "Slash", KeyboardEvent.DOM_VK_SLASH, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_2,
+                   modifiers:{shiftKey:1}, chars:"?"},
+                  "?", "Slash", KeyboardEvent.DOM_VK_SLASH, "?", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_2,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "/", "Slash", KeyboardEvent.DOM_VK_SLASH, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_2,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "?", "Slash", KeyboardEvent.DOM_VK_SLASH, "?", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_2,
+                   modifiers:{altKey:1}, chars:"/"},
+                  "/", "Slash", KeyboardEvent.DOM_VK_SLASH, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_2,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"?"},
+                  "?", "Slash", KeyboardEvent.DOM_VK_SLASH, "?", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_3,
+                   modifiers:{}, chars:"`"},
+                  "`", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "`", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_3,
+                   modifiers:{shiftKey:1}, chars:"~"},
+                  "~", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "~", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_3,
+                   modifiers:{ctrlKey:1}, chars:""},
+                  "`", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "`", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_3,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "~", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "~", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_3,
+                   modifiers:{altKey:1}, chars:"`"},
+                  "`", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "`", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_3,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"~"},
+                  "~", "Backquote", KeyboardEvent.DOM_VK_BACK_QUOTE, "~", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Numpad
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD0,
+                   modifiers:{numLockKey:1}, chars:"0"},
+                  "0", "Numpad0", KeyboardEvent.DOM_VK_NUMPAD0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD1,
+                   modifiers:{numLockKey:1}, chars:"1"},
+                  "1", "Numpad1", KeyboardEvent.DOM_VK_NUMPAD1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD2,
+                   modifiers:{numLockKey:1}, chars:"2"},
+                  "2", "Numpad2", KeyboardEvent.DOM_VK_NUMPAD2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD3,
+                   modifiers:{numLockKey:1}, chars:"3"},
+                  "3", "Numpad3", KeyboardEvent.DOM_VK_NUMPAD3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD4,
+                   modifiers:{numLockKey:1}, chars:"4"},
+                  "4", "Numpad4", KeyboardEvent.DOM_VK_NUMPAD4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD5,
+                   modifiers:{numLockKey:1}, chars:"5"},
+                  "5", "Numpad5", KeyboardEvent.DOM_VK_NUMPAD5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD6,
+                   modifiers:{numLockKey:1}, chars:"6"},
+                  "6", "Numpad6", KeyboardEvent.DOM_VK_NUMPAD6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD7,
+                   modifiers:{numLockKey:1}, chars:"7"},
+                  "7", "Numpad7", KeyboardEvent.DOM_VK_NUMPAD7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD8,
+                   modifiers:{numLockKey:1}, chars:"8"},
+                  "8", "Numpad8", KeyboardEvent.DOM_VK_NUMPAD8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD9,
+                   modifiers:{numLockKey:1}, chars:"9"},
+                  "9", "Numpad9", KeyboardEvent.DOM_VK_NUMPAD9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_MULTIPLY,
+                   modifiers:{numLockKey:1}, chars:"*"},
+                  "*", "NumpadMultiply", KeyboardEvent.DOM_VK_MULTIPLY, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_MULTIPLY,
+                   modifiers:{numLockKey:1, shiftKey:1}, chars:"*"},
+                  "*", "NumpadMultiply", KeyboardEvent.DOM_VK_MULTIPLY, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_ADD,
+                   modifiers:{numLockKey:1}, chars:"+"},
+                  "+", "NumpadAdd", KeyboardEvent.DOM_VK_ADD, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_ADD,
+                   modifiers:{numLockKey:1, shiftKey:1}, chars:"+"},
+                  "+", "NumpadAdd", KeyboardEvent.DOM_VK_ADD, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    // VK_SEPARATOR is keycode for NEC's PC-98 series whose keyboard layout was
+    // different from current PC's keyboard layout and it cannot connect to
+    // current PC.  Note that even if we synthesize WM_KEYDOWN with
+    // VK_SEPARATOR, it doesn't work on Win7.
+    //yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_SEPARATOR,
+    //               modifiers:{numLockKey:1}, chars:""},
+    //              "", "", KeyboardEvent.DOM_VK_SEPARATOR, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    //yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_SEPARATOR,
+    //               modifiers:{numLockKey:1, shiftKey:1}, chars:""},
+    //              "", "", KeyboardEvent.DOM_VK_SEPARATOR, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_SUBTRACT,
+                   modifiers:{numLockKey:1}, chars:"-"},
+                  "-", "NumpadSubtract", KeyboardEvent.DOM_VK_SUBTRACT, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_SUBTRACT,
+                   modifiers:{numLockKey:1, shiftKey:1}, chars:"-"},
+                  "-", "NumpadSubtract", KeyboardEvent.DOM_VK_SUBTRACT, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_DECIMAL,
+                   modifiers:{numLockKey:1}, chars:"."},
+                  ".", "NumpadDecimal", KeyboardEvent.DOM_VK_DECIMAL, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_DECIMAL,
+                   modifiers:{numLockKey:1, shiftKey:1}, chars:"."},
+                  ".", "NumpadDecimal", KeyboardEvent.DOM_VK_DECIMAL, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_DIVIDE,
+                   modifiers:{numLockKey:1}, chars:"/"},
+                  "/", "NumpadDivide", KeyboardEvent.DOM_VK_DIVIDE, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_DIVIDE,
+                   modifiers:{numLockKey:1, shiftKey:1}, chars:"/"},
+                  "/", "NumpadDivide", KeyboardEvent.DOM_VK_DIVIDE, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_RETURN,
+                   modifiers:{numLockKey:1}, chars:"\r"},
+                  "Enter", "NumpadEnter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_RETURN,
+                   modifiers:{numLockKey:1, shiftKey:1}, chars:"\r"},
+                  "Enter", "NumpadEnter", KeyboardEvent.DOM_VK_RETURN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+
+    // Numpad without NumLock
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_PRIOR,
+                   modifiers:{}, chars:""},
+                  "PageUp", "Numpad9", KeyboardEvent.DOM_VK_PAGE_UP, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_NEXT,
+                   modifiers:{}, chars:""},
+                  "PageDown", "Numpad3", KeyboardEvent.DOM_VK_PAGE_DOWN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_END,
+                   modifiers:{}, chars:""},
+                  "End", "Numpad1", KeyboardEvent.DOM_VK_END, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_HOME,
+                   modifiers:{}, chars:""},
+                  "Home", "Numpad7", KeyboardEvent.DOM_VK_HOME, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_LEFT,
+                   modifiers:{}, chars:""},
+                  "ArrowLeft", "Numpad4", KeyboardEvent.DOM_VK_LEFT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_UP,
+                   modifiers:{}, chars:""},
+                  "ArrowUp", "Numpad8", KeyboardEvent.DOM_VK_UP, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_RIGHT,
+                   modifiers:{}, chars:""},
+                  "ArrowRight", "Numpad6", KeyboardEvent.DOM_VK_RIGHT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_DOWN,
+                   modifiers:{}, chars:""},
+                  "ArrowDown", "Numpad2", KeyboardEvent.DOM_VK_DOWN, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_INSERT,
+                   modifiers:{}, chars:""},
+                  "Insert", "Numpad0", KeyboardEvent.DOM_VK_INSERT, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_NUMPAD_DELETE,
+                   modifiers:{}, chars:""},
+                  "Delete", "NumpadDecimal", KeyboardEvent.DOM_VK_DELETE, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_CLEAR,
+                   modifiers:{}, chars:""},
+                  "Clear", "Numpad5", KeyboardEvent.DOM_VK_CLEAR, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+
+    // Even if widget receives unknown keycode, it should dispatch key events
+    // whose keycode is 0 rather than native keycode.
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:0x3A,
+                   modifiers:{numLockKey:1}, chars:""},
+                  "Unidentified", "", 0, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // French
+    // Numeric
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_0,
+                   modifiers:{}, chars:"\u00E0"},
+                  "\u00E0", "Digit0", KeyboardEvent.DOM_VK_0, "\u00E0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_0,
+                   modifiers:{shiftKey:1}, chars:"0"},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_1,
+                   modifiers:{}, chars:"&"},
+                  "&", "Digit1", KeyboardEvent.DOM_VK_1, "&", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_1,
+                   modifiers:{shiftKey:1}, chars:"1"},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_2,
+                   modifiers:{}, chars:"\u00E9"},
+                  "\u00E9", "Digit2", KeyboardEvent.DOM_VK_2, "\u00E9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_2,
+                   modifiers:{shiftKey:1}, chars:"2"},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_3,
+                   modifiers:{}, chars:"\""},
+                  "\"", "Digit3", KeyboardEvent.DOM_VK_3, "\"", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_3,
+                   modifiers:{shiftKey:1}, chars:"3"},
+                  "3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_4,
+                   modifiers:{}, chars:"'"},
+                  "'", "Digit4", KeyboardEvent.DOM_VK_4, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_4,
+                   modifiers:{shiftKey:1}, chars:"4"},
+                  "4", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_5,
+                   modifiers:{}, chars:"("},
+                  "(", "Digit5", KeyboardEvent.DOM_VK_5, "(", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_5,
+                   modifiers:{shiftKey:1}, chars:"5"},
+                  "5", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_6,
+                   modifiers:{}, chars:"-"},
+                  "-", "Digit6", KeyboardEvent.DOM_VK_6, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_6,
+                   modifiers:{shiftKey:1}, chars:"6"},
+                  "6", "Digit6", KeyboardEvent.DOM_VK_6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_7,
+                   modifiers:{}, chars:"\u00E8"},
+                  "\u00E8", "Digit7", KeyboardEvent.DOM_VK_7, "\u00E8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_7,
+                   modifiers:{shiftKey:1}, chars:"7"},
+                  "7", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_8,
+                   modifiers:{}, chars:"_"},
+                  "_", "Digit8", KeyboardEvent.DOM_VK_8, "_", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_8,
+                   modifiers:{shiftKey:1}, chars:"8"},
+                  "8", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_9,
+                   modifiers:{}, chars:"\u00E7"},
+                  "\u00E7", "Digit9", KeyboardEvent.DOM_VK_9, "\u00E7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_9,
+                   modifiers:{shiftKey:1}, chars:"9"},
+                  "9", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Numeric with ShiftLock
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_0,
+                   modifiers:{capsLockKey:1}, chars:"0"},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_0,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"\u00E0"},
+                  "\u00E0", "Digit0", KeyboardEvent.DOM_VK_0, "\u00E0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_1,
+                   modifiers:{capsLockKey:1}, chars:"1"},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_1,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"&"},
+                  "&", "Digit1", KeyboardEvent.DOM_VK_1, "&", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_2,
+                   modifiers:{capsLockKey:1}, chars:"2"},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_2,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"\u00E9"},
+                  "\u00E9", "Digit2", KeyboardEvent.DOM_VK_2, "\u00E9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_3,
+                   modifiers:{capsLockKey:1}, chars:"3"},
+                  "3", "Digit3", KeyboardEvent.DOM_VK_3, "3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_3,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"\""},
+                  "\"", "Digit3", KeyboardEvent.DOM_VK_3, "\"", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_4,
+                   modifiers:{capsLockKey:1}, chars:"4"},
+                  "4", "Digit4", KeyboardEvent.DOM_VK_4, "4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_4,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"'"},
+                  "'", "Digit4", KeyboardEvent.DOM_VK_4, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_5,
+                   modifiers:{capsLockKey:1}, chars:"5"},
+                  "5", "Digit5", KeyboardEvent.DOM_VK_5, "5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_5,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"("},
+                  "(", "Digit5", KeyboardEvent.DOM_VK_5, "(", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_6,
+                   modifiers:{capsLockKey:1}, chars:"6"},
+                  "6", "Digit6", KeyboardEvent.DOM_VK_6, "6", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_6,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"-"},
+                  "-", "Digit6", KeyboardEvent.DOM_VK_6, "-", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_7,
+                   modifiers:{capsLockKey:1}, chars:"7"},
+                  "7", "Digit7", KeyboardEvent.DOM_VK_7, "7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_7,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"\u00E8"},
+                  "\u00E8", "Digit7", KeyboardEvent.DOM_VK_7, "\u00E8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_8,
+                   modifiers:{capsLockKey:1}, chars:"8"},
+                  "8", "Digit8", KeyboardEvent.DOM_VK_8, "8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_8,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"_"},
+                  "_", "Digit8", KeyboardEvent.DOM_VK_8, "_", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_9,
+                   modifiers:{capsLockKey:1}, chars:"9"},
+                  "9", "Digit9", KeyboardEvent.DOM_VK_9, "9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_9,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"\u00E7"},
+                  "\u00E7", "Digit9", KeyboardEvent.DOM_VK_9, "\u00E7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // OEM keys
+    // If the key doesn't cause ASCII character even with or without Shift key, keyCode value should be same as
+    // the key which causes the virtual keycode on ANSI keyboard layout.
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{}, chars:"\u00B2"},
+                  "\u00B2", "Backquote", KeyboardEvent.DOM_VK_QUOTE, "\u00B2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "", "Backquote", KeyboardEvent.DOM_VK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_4,
+                   modifiers:{}, chars:")"},
+                  ")", "Minus", KeyboardEvent.DOM_VK_CLOSE_PAREN, ")", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_4,
+                   modifiers:{shiftKey:1}, chars:"\u00B0"},
+                  "\u00B0", "Minus", KeyboardEvent.DOM_VK_CLOSE_PAREN, "\u00B0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_PLUS,
+                   modifiers:{}, chars:"="},
+                  "=", "Equal", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_PLUS,
+                   modifiers:{shiftKey:1}, chars:"+"},
+                  "+", "Equal", KeyboardEvent.DOM_VK_EQUALS, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    //yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+    //               modifiers:{}, chars:""},
+    //              "Dead", "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // Dead-key
+    //yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+    //               modifiers:{shiftKey:1}, chars:""},
+    //              ["^^", "^", "^", "^"], "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // Dead-key
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{}, chars:"$"},
+                  "$", "BracketRight", KeyboardEvent.DOM_VK_DOLLAR, "$", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{shiftKey:1}, chars:"\u00A3"},
+                  "\u00A3", "BracketRight", KeyboardEvent.DOM_VK_DOLLAR, "\u00A3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_3,
+                   modifiers:{}, chars:"\u00F9"},
+                  "\u00F9", "Quote", KeyboardEvent.DOM_VK_PERCENT, "\u00F9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_3,
+                   modifiers:{shiftKey:1}, chars:"%"},
+                  "%", "Quote", KeyboardEvent.DOM_VK_PERCENT, "%", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_5,
+                   modifiers:{}, chars:"*"},
+                  "*", "Backslash", KeyboardEvent.DOM_VK_ASTERISK, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_5,
+                   modifiers:{shiftKey:1}, chars:"\u00B5"},
+                  "\u00B5", "Backslash", KeyboardEvent.DOM_VK_ASTERISK, "\u00B5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_102,
+                   modifiers:{}, chars:"<"},
+                  "<", "IntlBackslash", KeyboardEvent.DOM_VK_LESS_THAN, "<", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_102,
+                   modifiers:{shiftKey:1}, chars:">"},
+                  ">", "IntlBackslash", KeyboardEvent.DOM_VK_LESS_THAN, ">", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_COMMA,
+                   modifiers:{}, chars:","},
+                  ",", "KeyM", KeyboardEvent.DOM_VK_COMMA, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_COMMA,
+                   modifiers:{shiftKey:1}, chars:"?"},
+                  "?", "KeyM", KeyboardEvent.DOM_VK_COMMA, "?", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_PERIOD,
+                   modifiers:{}, chars:";"},
+                  ";", "Comma", KeyboardEvent.DOM_VK_SEMICOLON, ";", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_PERIOD,
+                   modifiers:{shiftKey:1}, chars:"."},
+                  ".", "Comma", KeyboardEvent.DOM_VK_SEMICOLON, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_2,
+                   modifiers:{}, chars:":"},
+                  ":", "Period", KeyboardEvent.DOM_VK_COLON, ":", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_2,
+                   modifiers:{shiftKey:1}, chars:"/"},
+                  "/", "Period", KeyboardEvent.DOM_VK_COLON, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_8,
+                   modifiers:{}, chars:"!"},
+                  "!", "Slash", KeyboardEvent.DOM_VK_EXCLAMATION, "!", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_8,
+                   modifiers:{shiftKey:1}, chars:"\u00A7"},
+                  "\u00A7", "Slash", KeyboardEvent.DOM_VK_EXCLAMATION, "\u00A7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // OEM keys with ShiftLock
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{capsLockKey:1}, chars:"\u00B2"},
+                  "\u00B2", "Backquote", KeyboardEvent.DOM_VK_QUOTE, "\u00B2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:""},
+                  "", "Backquote", KeyboardEvent.DOM_VK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_4,
+                   modifiers:{capsLockKey:1}, chars:"\u00B0"},
+                  "\u00B0", "Minus", KeyboardEvent.DOM_VK_CLOSE_PAREN, "\u00B0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_4,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:")"},
+                  ")", "Minus", KeyboardEvent.DOM_VK_CLOSE_PAREN, ")", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_PLUS,
+                   modifiers:{capsLockKey:1}, chars:"+"},
+                  "+", "Equal", KeyboardEvent.DOM_VK_EQUALS, "+", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_PLUS,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"="},
+                  "=", "Equal", KeyboardEvent.DOM_VK_EQUALS, "=", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    //yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+    //               modifiers:{capsLockKey:1}, chars:""},
+    //              "Dead", "BracketLeft", KeyboardLayout.DOM_VK_CLOSE_BRACKET, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // Dead-key
+    //yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+    //               modifiers:{capsLockKey:1, shiftKey:1}, chars:""},
+    //              ["\u00A8\u00A8", "\u00A8", "\u00A8", "\u00A8"], "BracketLeft", KeyboardLayout.DOM_VK_CLOSE_BRACKET, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // Dead-key
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{capsLockKey:1}, chars:"\u00A3"},
+                  "\u00A3", "BracketRight", KeyboardEvent.DOM_VK_DOLLAR, "\u00A3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"$"},
+                  "$", "BracketRight", KeyboardEvent.DOM_VK_DOLLAR, "$", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_3,
+                   modifiers:{capsLockKey:1}, chars:"%"},
+                  "%", "Quote", KeyboardEvent.DOM_VK_PERCENT, "%", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_3,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"\u00F9"},
+                  "\u00F9", "Quote", KeyboardEvent.DOM_VK_PERCENT, "\u00F9", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_5,
+                   modifiers:{capsLockKey:1}, chars:"\u00B5"},
+                  "\u00B5", "Backslash", KeyboardEvent.DOM_VK_ASTERISK, "\u00B5", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_5,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"*"},
+                  "*", "Backslash", KeyboardEvent.DOM_VK_ASTERISK, "*", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_102,
+                   modifiers:{capsLockKey:1}, chars:"<"},
+                  "<", "IntlBackslash", KeyboardEvent.DOM_VK_LESS_THAN, "<", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_102,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:">"},
+                  ">", "IntlBackslash", KeyboardEvent.DOM_VK_LESS_THAN, ">", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_COMMA,
+                   modifiers:{capsLockKey:1}, chars:"?"},
+                  "?", "KeyM", KeyboardEvent.DOM_VK_COMMA, "?", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_COMMA,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:","},
+                  ",", "KeyM", KeyboardEvent.DOM_VK_COMMA, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_PERIOD,
+                   modifiers:{capsLockKey:1}, chars:"."},
+                  ".", "Comma", KeyboardEvent.DOM_VK_SEMICOLON, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_PERIOD,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:";"},
+                  ";", "Comma", KeyboardEvent.DOM_VK_SEMICOLON, ";", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_2,
+                   modifiers:{capsLockKey:1}, chars:"/"},
+                  "/", "Period", KeyboardEvent.DOM_VK_COLON, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_2,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:":"},
+                  ":", "Period", KeyboardEvent.DOM_VK_COLON, ":", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_8,
+                   modifiers:{capsLockKey:1}, chars:"\u00A7"},
+                  "\u00A7", "Slash", KeyboardEvent.DOM_VK_EXCLAMATION, "\u00A7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_8,
+                   modifiers:{capsLockKey:1, shiftKey:1}, chars:"!"},
+                  "!", "Slash", KeyboardEvent.DOM_VK_EXCLAMATION, "!", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // AltGr
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_0,
+                   modifiers:{altGrKey:1}, chars:"@"},
+                  "@", "Digit0", KeyboardEvent.DOM_VK_0, "@", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // AltGr + Digit1 does not cause text input in French layout.  In this case,
+    // AltGr shouldn't be used for a modifier of shortcut.  Therefore, not
+    // receiving `keypress` event even in the system group is fine.
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_1,
+                   modifiers:{altGrKey:1}, chars:""},
+                  "&", "Digit1", KeyboardEvent.DOM_VK_1, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    //yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_2,
+    //               modifiers:{altGrKey:1}, chars:""},
+    //              "Dead", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // Dead-key
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_3,
+                   modifiers:{altGrKey:1}, chars:"#"},
+                  "#", "Digit3", KeyboardEvent.DOM_VK_3, "#", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_4,
+                   modifiers:{altGrKey:1}, chars:"{"},
+                  "{", "Digit4", KeyboardEvent.DOM_VK_4, "{", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_5,
+                   modifiers:{altGrKey:1}, chars:"["},
+                  "[", "Digit5", KeyboardEvent.DOM_VK_5, "[", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_6,
+                   modifiers:{altGrKey:1}, chars:"|"},
+                  "|", "Digit6", KeyboardEvent.DOM_VK_6, "|", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    //yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_7,
+    //               modifiers:{altGrKey:1}, chars:""},
+    //              "Dead", "Digit7", KeyboardEvent.DOM_VK_7, "", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD); // Dead-key
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_8,
+                   modifiers:{altGrKey:1}, chars:"\\"},
+                  "\\", "Digit8", KeyboardEvent.DOM_VK_8, "\\", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_9,
+                   modifiers:{altGrKey:1}, chars:"^"},
+                  "^", "Digit9", KeyboardEvent.DOM_VK_9, "^", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_4,
+                   modifiers:{altGrKey:1}, chars:"]"},
+                  "]", "Minus", KeyboardEvent.DOM_VK_CLOSE_PAREN, "]", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_PLUS,
+                   modifiers:{altGrKey:1}, chars:"}"},
+                  "}", "Equal", KeyboardEvent.DOM_VK_EQUALS, "}", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // AltGr emulated with Ctrl and Alt
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_0,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"@", isInputtingCharacters:true},
+                  "@", "Digit0", KeyboardEvent.DOM_VK_0, "@", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_0,
+                   modifiers:{ctrlKey:1, altKey:1, shiftKey:1}, chars:"", isInputtingCharacters:false},
+                  "0", "Digit0", KeyboardEvent.DOM_VK_0, "0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    // Different from AltGr + Digit1 case, Ctrl + Alt + Digit1 should be
+    // available as a shortcut key.  Therefore, `keypress` event needs to be
+    // fired.
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_1,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"", isInputtingCharacters:false},
+                  "&", "Digit1", KeyboardEvent.DOM_VK_1, "&", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_1,
+                   modifiers:{ctrlKey:1, altKey:1, shiftKey:1}, chars:"", isInputtingCharacters:false},
+                  "1", "Digit1", KeyboardEvent.DOM_VK_1, "1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // German
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:WIN_VK_OEM_2,
+                   modifiers:{}, chars:"#"},
+                  "#", "Backslash", KeyboardEvent.DOM_VK_HASH, "#", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:WIN_VK_OEM_2,
+                   modifiers:{shiftKey:1}, chars:"'"},
+                  "'", "Backslash", KeyboardEvent.DOM_VK_HASH, "'", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Khmer
+    yield testKey({layout:KEYBOARD_LAYOUT_KHMER, keyCode:WIN_VK_2,
+                    modifiers:{}, chars:"\u17E2"},
+                  "\u17E2", "Digit2", KeyboardEvent.DOM_VK_2, "\u17E2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_KHMER, keyCode:WIN_VK_2,
+                    modifiers:{shiftKey:1}, chars:"\u17D7"},
+                  "\u17D7", "Digit2", KeyboardEvent.DOM_VK_2, "\u17D7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_KHMER, keyCode:WIN_VK_2, // Ctrl+2 should cause inputting Euro sign.
+                    modifiers:{ctrlKey:1}, chars:"\u20AC", isInputtingCharacters:true},
+                  "\u20AC", "Digit2", KeyboardEvent.DOM_VK_2, "\u20AC", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_KHMER, keyCode:WIN_VK_2, // Ctrl+Shift+2 shouldn't cause any input.
+                    modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                  "\u17D7", "Digit2", KeyboardEvent.DOM_VK_2, "\u17D7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_KHMER, keyCode:WIN_VK_2,
+                    modifiers:{altKey:1}, chars:"\u17E2"},
+                  "\u17E2", "Digit2", KeyboardEvent.DOM_VK_2, "\u17E2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_KHMER, keyCode:WIN_VK_2,
+                    modifiers:{altKey:1, shiftKey:1}, chars:"\u17D7"},
+                  "\u17D7", "Digit2", KeyboardEvent.DOM_VK_2, "\u17D7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_KHMER, keyCode:WIN_VK_2,
+                    modifiers:{altGrKey:1}, chars:"2"},
+                  "2", "Digit2", KeyboardEvent.DOM_VK_2, "2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_KHMER, keyCode:WIN_VK_2,
+                    modifiers:{altGrKey:1, shiftKey:1}, chars:"\u19E2"},
+                  "\u19E2", "Digit2", KeyboardEvent.DOM_VK_2, "\u19E2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Norwegian
+    yield testKey({layout:KEYBOARD_LAYOUT_NORWEGIAN, keyCode:WIN_VK_OEM_5,
+                   modifiers:{}, chars:"|"},
+                  "|", "Backquote", KeyboardEvent.DOM_VK_PIPE, "|", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_NORWEGIAN, keyCode:WIN_VK_OEM_5,
+                   modifiers:{shiftKey:1}, chars:"\u00A7"},
+                  "\u00A7", "Backquote", KeyboardEvent.DOM_VK_PIPE, "\u00A7", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // Brazilian ABNT
+    yield testKey({layout:KEYBOARD_LAYOUT_BRAZILIAN_ABNT, keyCode:WIN_VK_ABNT_C1,
+                   modifiers:{}, chars:"/"},
+                  "/", "IntlBackslash", KeyboardEvent.DOM_VK_SLASH, "/", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_BRAZILIAN_ABNT, keyCode:WIN_VK_ABNT_C1,
+                   modifiers:{shiftKey:1}, chars:"?"},
+                  "?", "IntlBackslash", KeyboardEvent.DOM_VK_SLASH, "?", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_BRAZILIAN_ABNT, keyCode:WIN_VK_ABNT_C2,
+                   modifiers:{numLockKey:1}, chars:"."},
+                  ".", "NumpadComma", KeyboardEvent.DOM_VK_SEPARATOR, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_BRAZILIAN_ABNT, keyCode:WIN_VK_DECIMAL,
+                   modifiers:{numLockKey:1}, chars:","},
+                  ",", "NumpadDecimal", KeyboardEvent.DOM_VK_DECIMAL, ",", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+
+    // Mac JIS keyboard
+    // The separator key on JIS keyboard for Mac doesn't cause any character even with Japanese keyboard layout.
+    yield testKey({layout:KEYBOARD_LAYOUT_JAPANESE, keyCode:WIN_VK_ABNT_C2,
+                   modifiers:{numLockKey:1}, chars:""},
+                  "", "NumpadComma", KeyboardEvent.DOM_VK_SEPARATOR, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+    yield testKey({layout:KEYBOARD_LAYOUT_JAPANESE, keyCode:WIN_VK_DECIMAL,
+                   modifiers:{numLockKey:1}, chars:"."},
+                  ".", "NumpadDecimal", KeyboardEvent.DOM_VK_DECIMAL, ".", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_NUMPAD);
+
+    // Dead keys on any layouts
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+                   modifiers:{}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+                   modifiers:{}, chars:"^^"},
+                  ["^^", "^", "^", "^"], "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "^^", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+                   modifiers:{}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"\u00E2"},
+                  ["\u00E2", "\u00E2", "a"], "KeyQ", KeyboardEvent.DOM_VK_A, "\u00E2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+                   modifiers:{}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1}, chars:"\u00C2"},
+                  ["\u00C2", "\u00C2", "A"], "KeyQ", KeyboardEvent.DOM_VK_A, "\u00C2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+                   modifiers:{}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_Q,
+                   modifiers:{}, chars:"^q"},
+                  ["^q", "^", "q", "q"], "KeyA", KeyboardEvent.DOM_VK_Q, "^q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+                   modifiers:{shiftKey:1}, chars:"\u00A8\u00A8"},
+                  ["\u00A8\u00A8", "\u00A8", "\u00A8", "\u00A8"], "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "\u00A8\u00A8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1}, chars:"\u00C4"},
+                  ["\u00C4", "\u00C4", "A"], "KeyQ", KeyboardEvent.DOM_VK_A, "\u00C4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"\u00E4"},
+                  ["\u00E4", "\u00E4", "a"], "KeyQ", KeyboardEvent.DOM_VK_A, "\u00E4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_OEM_6,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_FRENCH, keyCode:WIN_VK_Q,
+                   modifiers:{shiftKey:1}, chars:"\u00A8Q"},
+                  ["\u00A8Q", "\u00A8", "Q", "Q"], "KeyA", KeyboardEvent.DOM_VK_Q, "\u00A8Q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{}, chars:"``"},
+                  ["``", "`", "`", "`"], "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "``", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"\u00E0"},
+                  ["\u00E0", "\u00E0", "a"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00E0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1}, chars:"\u00C0"},
+                  ["\u00C0", "\u00C0", "A"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00C0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_Q,
+                   modifiers:{}, chars:"`q"},
+                  ["`q", "`", "q", "q"], "KeyQ", KeyboardEvent.DOM_VK_Q, "`q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{shiftKey:1}, chars:"^^"},
+                  ["^^", "^", "^", "^"], "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "^^", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1}, chars:"\u00C2"},
+                  ["\u00C2", "\u00C2", "A"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00C2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"\u00E2"},
+                  ["\u00E2", "\u00E2", "a"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00E2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_Q,
+                   modifiers:{shiftKey:1}, chars:"^Q"},
+                  ["^Q", "^", "Q", "Q"], "KeyQ", KeyboardEvent.DOM_VK_Q, "^Q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{}, chars:""},
+                  "Dead", "Quote", KeyboardEvent.DOM_VK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{}, chars:"\u00B4\u00B4"},
+                  ["\u00B4\u00B4", "\u00B4", "\u00B4", "\u00B4"], "Quote", KeyboardEvent.DOM_VK_QUOTE, "\u00B4\u00B4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{}, chars:""},
+                  "Dead", "Quote", KeyboardEvent.DOM_VK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"\u00E1"},
+                  ["\u00E1", "\u00E1", "a"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00E1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{}, chars:""},
+                  "Dead", "Quote", KeyboardEvent.DOM_VK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1}, chars:"\u00C1"},
+                  ["\u00C1", "\u00C1", "A"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00C1", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{}, chars:""},
+                  "Dead", "Quote", KeyboardEvent.DOM_VK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_Q,
+                   modifiers:{}, chars:"\u00B4q"},
+                  ["\u00B4q", "\u00B4", "q", "q"], "KeyQ", KeyboardEvent.DOM_VK_Q, "\u00B4q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "Quote", KeyboardEvent.DOM_VK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{shiftKey:1}, chars:"\u00A8\u00A8"},
+                  ["\u00A8\u00A8", "\u00A8", "\u00A8", "\u00A8"], "Quote", KeyboardEvent.DOM_VK_QUOTE, "\u00A8\u00A8", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "Quote", KeyboardEvent.DOM_VK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1}, chars:"\u00C4"},
+                  ["\u00C4", "\u00C4", "A"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00C4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "Quote", KeyboardEvent.DOM_VK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"\u00E4"},
+                  ["\u00E4", "\u00E4", "a"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00E4", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_7,
+                   modifiers:{shiftKey:1}, chars:""},
+                  "Dead", "Quote", KeyboardEvent.DOM_VK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_Q,
+                   modifiers:{shiftKey:1}, chars:"\u00A8Q"},
+                  ["\u00A8Q", "\u00A8", "Q", "Q"], "KeyQ", KeyboardEvent.DOM_VK_Q, "\u00A8Q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_NORWEGIAN, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altGrKey:1}, chars:""},
+                  "Dead", "BracketRight", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_NORWEGIAN, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"\u00E3"},
+                  ["\u00E3", "\u00E3", "a"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00E3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_NORWEGIAN, keyCode:WIN_VK_OEM_1,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:""},
+                  "Dead", "BracketRight", KeyboardEvent.DOM_VK_CIRCUMFLEX, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_NORWEGIAN, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"\u00E3"},
+                  ["\u00E3", "\u00E3", "a"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00E3", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    if (OS_VERSION >= WIN8) {
+      // On Russian Mnemonic layout, both 'KeyS' and 'KeyC' are dead key.  However, the sequence 'KeyS' -> 'KeyC' causes a composite character.
+      yield testKey({layout:KEYBOARD_LAYOUT_RUSSIAN_MNEMONIC, keyCode:WIN_VK_S,
+                     modifiers:{}, chars:""},
+                    "Dead", "KeyS", KeyboardEvent.DOM_VK_S, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+      yield testKey({layout:KEYBOARD_LAYOUT_RUSSIAN_MNEMONIC, keyCode:WIN_VK_S,
+                     modifiers:{}, chars:"\u0441\u0441"},
+                    ["\u0441\u0441", "\u0441", "\u0441", "\u0441"], "KeyS", KeyboardEvent.DOM_VK_S, "\u0441\u0441", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+      yield testKey({layout:KEYBOARD_LAYOUT_RUSSIAN_MNEMONIC, keyCode:WIN_VK_C,
+                     modifiers:{}, chars:""},
+                    "Dead", "KeyC", KeyboardEvent.DOM_VK_C, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+      yield testKey({layout:KEYBOARD_LAYOUT_RUSSIAN_MNEMONIC, keyCode:WIN_VK_C,
+                     modifiers:{}, chars:"\u0446\u0446"},
+                    ["\u0446\u0446", "\u0446", "\u0446", "\u0446"], "KeyC", KeyboardEvent.DOM_VK_C, "\u0446\u0446", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+      yield testKey({layout:KEYBOARD_LAYOUT_RUSSIAN_MNEMONIC, keyCode:WIN_VK_S,
+                     modifiers:{}, chars:""},
+                    "Dead", "KeyS", KeyboardEvent.DOM_VK_S, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+      yield testKey({layout:KEYBOARD_LAYOUT_RUSSIAN_MNEMONIC, keyCode:WIN_VK_C,
+                     modifiers:{}, chars:"\u0449"},
+                    ["\u0449", "\u0449", "\u0446"], "KeyC", KeyboardEvent.DOM_VK_C, "\u0449", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    }
+
+    yield testKey({layout:KEYBOARD_LAYOUT_RUSSIAN, keyCode:WIN_VK_A,
+                   modifiers:{altKey:1,ctrlKey:1}, chars:""},
+                   "\u0444", "KeyA", KeyboardEvent.DOM_VK_A, "a", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_RUSSIAN, keyCode:WIN_VK_A,
+                   modifiers:{altKey:1,ctrlKey:1,shiftKey:1}, chars:""},
+                   "\u0424", "KeyA", KeyboardEvent.DOM_VK_A, "A", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_RUSSIAN, keyCode:WIN_VK_T,
+                   modifiers:{altKey:1,ctrlKey:1}, chars:""},
+                   "\u0435", "KeyT", KeyboardEvent.DOM_VK_T, "t", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_RUSSIAN, keyCode:WIN_VK_T,
+                   modifiers:{altKey:1,ctrlKey:1,shiftKey:1}, chars:""},
+                   "\u0415", "KeyT", KeyboardEvent.DOM_VK_T, "T", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    // When Alt key is pressed, dead key sequence is generated with WM_SYSKEYDOWN, WM_SYSDEADCHAR, WM_SYSCHAR and WM_SYSKEYUP.
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1}, chars:"``"},
+                  ["``", "`", "`", "`"], "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "``", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{altKey:1}, chars:"\u00E0"},
+                  ["\u00E0", "\u00E0", "a"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00E0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00C0"},
+                  ["\u00C0", "\u00C0", "A"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00C0", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_Q,
+                   modifiers:{altKey:1}, chars:"`q"},
+                  ["`q", "`", "q", "q"], "KeyQ", KeyboardEvent.DOM_VK_Q, "`q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1, shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"^^"},
+                  ["^^", "^", "^", "^"], "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "^^", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1, shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"\u00C2"},
+                  ["\u00C2", "\u00C2", "A"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00C2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1, shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_A,
+                   modifiers:{altKey:1}, chars:"\u00E2"},
+                  ["\u00E2", "\u00E2", "a"], "KeyA", KeyboardEvent.DOM_VK_A, "\u00E2", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_OEM_1,
+                   modifiers:{altKey:1, shiftKey:1}, chars:""},
+                  "Dead", "BracketLeft", KeyboardEvent.DOM_VK_BACK_QUOTE, "", SHOULD_DELIVER_KEYDOWN_KEYUP, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+    yield testKey({layout:KEYBOARD_LAYOUT_SPANISH, keyCode:WIN_VK_Q,
+                   modifiers:{altKey:1, shiftKey:1}, chars:"^Q"},
+                  ["^Q", "^", "Q", "Q"], "KeyQ", KeyboardEvent.DOM_VK_Q, "^Q", SHOULD_DELIVER_ALL, KeyboardEvent.DOM_KEY_LOCATION_STANDARD);
+
+    cleanup();
+  }
+
+
+  if (IS_WIN) {
+    yield* testKeysOnWindows();
+  } else if (IS_MAC) {
+    yield* testKeysOnMac();
+  } else {
+    cleanup();
+  }
+}
+
+// Test the activation (or not) of an HTML accesskey
+function* runAccessKeyTests()
+{
+  var button = document.getElementById("button");
+  var activationCount;
+
+  function onClick(e)
+  {
+    ++activationCount;
+  }
+
+  // The first parameter is the complete input event. The second and third parameters are
+  // what to test against.
+  function testKey(aEvent, aAccessKey, aShouldActivate)
+  {
+    activationCount = 0;
+    button.setAttribute("accesskey", aAccessKey);
+
+    return synthesizeKey(aEvent, "button", function() {
+
+      var currentTestName = eventToString(aEvent);
+
+      is(activationCount, aShouldActivate ? 1 : 0,
+         currentTestName + ", activating '" + aAccessKey + "'");
+
+      continueTest();
+    });
+  }
+
+  button.addEventListener("click", onClick);
+  
+  // These tests have to be per-plaform.
+  if (IS_MAC) {
+    // Basic sanity checks
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{}, chars:"a", unmodifiedChars:"a"},
+                  "a", false);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1}, chars:"\u0001", unmodifiedChars:"a"},
+                  "a", false);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1}, chars:"\u0001", unmodifiedChars:"a"},
+                  "A", false);
+
+    // Shift-ctrl does not activate accesskeys
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0001", unmodifiedChars:"A"},
+                  "a", false);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0001", unmodifiedChars:"A"},
+                  "A", false);
+    // Alt-ctrl activate accesskeys
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"\u0001", unmodifiedChars:"a"},
+                  "a", true);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"\u0001", unmodifiedChars:"a"},
+                  "A", true);
+            
+    // Greek layout can activate a Latin accesskey
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"\u0001", unmodifiedChars:"\u03b1"},
+                  "a", true);
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"\u0001", unmodifiedChars:"\u03b1"},
+                  "A", true);
+    // ... and a Greek accesskey!
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"\u0001", unmodifiedChars:"\u03b1"},
+                  "\u03b1", true);
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"\u0001", unmodifiedChars:"\u03b1"},
+                  "\u0391", true);
+
+    // bug 359638
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Period,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:".", unmodifiedChars:"."},
+                  ".", true);
+
+    // German (KCHR/KeyTranslate case)
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"a", unmodifiedChars:"a"},
+                  "a", true);
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:MAC_VK_ANSI_A,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"a", unmodifiedChars:"a"},
+                  "A", true);
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"\u00fc", unmodifiedChars:"\u00fc"},
+                  "\u00fc", true);
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:MAC_VK_ANSI_LeftBracket,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"\u00fc", unmodifiedChars:"\u00fc"},
+                  "\u00dc", true);
+  }
+  else if (IS_WIN) {
+    // Basic sanity checks
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"a"},
+                  "a", false);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1, altKey:1}, chars:"A"},
+                  "a", true);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1, altKey:1}, chars:"A"},
+                  "A", true);
+
+    // shift-alt-ctrl does not activate accesskeys
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{ctrlKey:1, shiftKey:1, altKey:1}, chars:""},
+                  "a", false);
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{ctrlKey:1, shiftKey:1, altKey:1}, chars:""},
+                  "A", false);
+
+    // Greek layout can activate a Latin accesskey
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1, altKey:1}, chars:"\u0391"},
+                  "a", true);
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1, altKey:1}, chars:"\u0391"},
+                  "A", true);
+    // ... and a Greek accesskey!
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1, altKey:1}, chars:"\u0391"},
+                  "\u03b1", true);
+    yield testKey({layout:KEYBOARD_LAYOUT_GREEK, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1, altKey:1}, chars:"\u0391"},
+                  "\u0391", true);
+
+    // bug 359638
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_PERIOD,
+                   modifiers:{shiftKey:1, altKey:1}, chars:".", unmodifiedChars:"."},
+                  ".", true);
+  }
+  
+  button.removeEventListener("click", onClick);
+}
+
+function* runXULKeyTests()
+{
+  var commandElements = {
+    expectedCommand: document.getElementById("expectedCommand"),
+    unexpectedCommand: document.getElementById("unexpectedCommand"),
+    expectedReservedCommand: document.getElementById("expectedReservedCommand")
+  };
+  // Enable all command elements.
+  for (var id in commandElements) {
+    commandElements[id].removeAttribute("disabled");
+  }
+
+  var keyEvents = [];
+
+  function onKeyInDefaultEventGroup(aDOMEvent)
+  {
+    if (isModifierKeyEvent(aDOMEvent)) {
+      return;
+    }
+    keyEvents.push({ type: aDOMEvent.type, group: "default", phase: getPhase(aDOMEvent), currentTarget: eventTargetToString(aDOMEvent.currentTarget) });
+  }
+
+  function onKeyInSystemEventGroup(aDOMEvent)
+  {
+    if (isModifierKeyEvent(aDOMEvent)) {
+      return;
+    }
+    keyEvents.push({ type: aDOMEvent.type, group: "system", phase: getPhase(aDOMEvent), currentTarget: eventTargetToString(aDOMEvent.currentTarget) });
+  }
+
+  var buttonParent = document.getElementById("button").parentNode;
+  buttonParent.addEventListener("keydown", onKeyInDefaultEventGroup, true);
+  buttonParent.addEventListener("keypress", onKeyInDefaultEventGroup, true);
+  buttonParent.addEventListener("keydown", onKeyInDefaultEventGroup);
+  buttonParent.addEventListener("keypress", onKeyInDefaultEventGroup);
+  SpecialPowers.addSystemEventListener(buttonParent, "keydown", onKeyInSystemEventGroup, true);
+  SpecialPowers.addSystemEventListener(buttonParent, "keypress", onKeyInSystemEventGroup, true);
+  SpecialPowers.addSystemEventListener(buttonParent, "keydown", onKeyInSystemEventGroup, false);
+  SpecialPowers.addSystemEventListener(buttonParent, "keypress", onKeyInSystemEventGroup, false);
+
+  function finializeKeyElementTest()
+  {
+    buttonParent.removeEventListener("keydown", onKeyInDefaultEventGroup, true);
+    buttonParent.removeEventListener("keypress", onKeyInDefaultEventGroup, true);
+    buttonParent.removeEventListener("keydown", onKeyInDefaultEventGroup);
+    buttonParent.removeEventListener("keypress", onKeyInDefaultEventGroup);
+    SpecialPowers.removeSystemEventListener(buttonParent, "keydown", onKeyInSystemEventGroup, true);
+    SpecialPowers.removeSystemEventListener(buttonParent, "keypress", onKeyInSystemEventGroup, true);
+    SpecialPowers.removeSystemEventListener(buttonParent, "keydown", onKeyInSystemEventGroup, false);
+    SpecialPowers.removeSystemEventListener(buttonParent, "keypress", onKeyInSystemEventGroup, false);
+  }
+
+  // If aKeyElement is empty string, this function tests if the event kicks
+  // no key elements.
+  function testKeyElement(aEvent, aKeyElementId)
+  {
+    var testName = "testKeyElement (with non-reserved command element): " + eventToString(aEvent) + " ";
+    var keyElement = aKeyElementId == "" ? null : document.getElementById(aKeyElementId);
+    if (keyElement) {
+      keyElement.setAttribute("command", "expectedCommand");
+    }
+
+    /* eslint-disable-next-line no-shadow */
+    for (var id in commandElements) {
+      commandElements[id].activeCount = 0;
+    }
+
+    keyEvents = [];
+    return synthesizeKey(aEvent, "button", function() {
+      if (keyElement) {
+        is(commandElements.expectedCommand.activeCount, 1, testName + "the command element (id='expectedCommand') should be preformed");
+      } else {
+        is(commandElements.expectedCommand.activeCount, 0, testName + "the command element (id='expectedCommand') shouldn't be preformed");
+      }
+      is(commandElements.unexpectedCommand.activeCount, 0, testName + "the command element (id='unexpectedCommand') shouldn't be preformed");
+      is(commandElements.expectedReservedCommand.activeCount, 0, testName + "the command element (id='expectedReservedCommand') shouldn't be preformed");
+
+      function checkFiredEvents()
+      {
+        let expectKeyPressEvent = aKeyElementId != "" ||
+                                  ((aEvent.modifiers.ctrlKey || aEvent.modifiers.altKey || aEvent.modifiers.metaKey) &&
+                                   (!IS_WIN || !aEvent.modifiers.altGrKey));
+        is(keyEvents.length, expectKeyPressEvent ? 8 : 4, testName + "wrong number events fired");
+        is(JSON.stringify(keyEvents[0]), JSON.stringify({ type: "keydown", group: "default", phase: "capture", currentTarget: eventTargetToString(buttonParent) }), testName + "keydown event should be fired on chrome in the default event group #0");
+        is(JSON.stringify(keyEvents[1]), JSON.stringify({ type: "keydown", group: "default", phase: "bubble", currentTarget: eventTargetToString(buttonParent) }), testName + "keydown event should be fired on chrome in the default event group #1");
+
+        is(JSON.stringify(keyEvents[2]), JSON.stringify({ type: "keydown", group: "system", phase: "capture", currentTarget: eventTargetToString(buttonParent) }), testName + "keydown event should be fired on chrome in the system event group #2");
+        is(JSON.stringify(keyEvents[3]), JSON.stringify({ type: "keydown", group: "system", phase: "bubble", currentTarget: eventTargetToString(buttonParent) }), testName + "keydown event should be fired on chrome in the system event group #3");
+
+        if (expectKeyPressEvent) {
+          is(JSON.stringify(keyEvents[4]), JSON.stringify({ type: "keypress", group: "default", phase: "capture", currentTarget: eventTargetToString(buttonParent) }), testName + "keypress event should be fired on chrome in the default event group #4");
+          is(JSON.stringify(keyEvents[5]), JSON.stringify({ type: "keypress", group: "default", phase: "bubble", currentTarget: eventTargetToString(buttonParent) }), testName + "keypress event should be fired on chrome in the default event group #5");
+
+          is(JSON.stringify(keyEvents[6]), JSON.stringify({ type: "keypress", group: "system", phase: "capture", currentTarget: eventTargetToString(buttonParent) }), testName + "keypress event should be fired on chrome in the system event group #6");
+          is(JSON.stringify(keyEvents[7]), JSON.stringify({ type: "keypress", group: "system", phase: "bubble", currentTarget: eventTargetToString(buttonParent) }), testName + "keypress event should be fired on chrome in the system event group #7");
+        }
+      }
+
+      checkFiredEvents();
+
+      if (keyElement) {
+        testName = "testKeyElement (with reserved command element): " + eventToString(aEvent) + " ";
+        keyElement.setAttribute("command", "expectedReservedCommand");
+
+        for (id in commandElements) {
+          commandElements[id].activeCount = 0;
+        }
+        keyEvents = [];
+        synthesizeKey(aEvent, "button", function() {
+          is(commandElements.expectedCommand.activeCount, 0, testName + "the command element (id='expectedCommand') shouldn't be preformed");
+          is(commandElements.unexpectedCommand.activeCount, 0, testName + "the command element (id='unexpectedCommand') shouldn't be preformed");
+          is(commandElements.expectedReservedCommand.activeCount, 1, testName + "the command element (id='expectedReservedCommand') should be preformed");
+
+          checkFiredEvents();
+
+          if (keyElement) {
+            keyElement.setAttribute("command", "unexpectedCommand");
+          }
+          continueTest();
+        });
+      } else {
+        if (keyElement) {
+          keyElement.setAttribute("command", "unexpectedCommand");
+        }
+        continueTest();
+      }
+    });
+  }
+
+  if (IS_MAC) {
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Semicolon,
+                          modifiers:{metaKey:1}, chars:";", unmodifiedChars:";"},
+                         "unshiftedKey");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Semicolon,
+                          modifiers:{metaKey:1, shiftKey:1}, chars:";", unmodifiedChars:":"},
+                         "shiftedKey");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Quote,
+                          modifiers:{metaKey:1}, chars:"'", unmodifiedChars:"'"},
+                         "reservedUnshiftedKey");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_Quote,
+                          modifiers:{metaKey:1, shiftKey:1}, chars:"\"", unmodifiedChars:"'"},
+                         "reservedShiftedKey");
+  }
+  else if (IS_WIN) {
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_1,
+                          modifiers:{ctrlKey:1}, chars:""},
+                         "unshiftedKey");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_1,
+                          modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                         "shiftedKey");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_7,
+                          modifiers:{ctrlKey:1}, chars:""},
+                         "reservedUnshiftedKey");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_OEM_7,
+                          modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                         "reservedShiftedKey");
+  }
+
+  // 429160
+  if (IS_MAC) {
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_F,
+                          modifiers:{metaKey:1, altKey:1}, chars:"\u0192", unmodifiedChars:"f"},
+                         "commandOptionF");
+  }
+  else if (IS_WIN) {
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_F,
+                          modifiers:{ctrlKey:1, altKey:1}, chars:"\u0006"},
+                         "commandOptionF");
+  }
+  
+  // 432112
+  if (IS_MAC) {
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_SWEDISH, keyCode:MAC_VK_ANSI_Minus,
+                          modifiers:{metaKey:1, shiftKey:1}, chars:"+", unmodifiedChars:"?"},
+                         "question");
+  }
+  else if (IS_WIN) {
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_SWEDISH, keyCode:WIN_VK_OEM_PLUS,
+                          modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                         "question");
+    // For testing if Ctrl+? is kicked without Shift state, temporarily disable
+    // Ctrl-+ key element.
+    var unshiftedPlusKeyElement = document.getElementById("unshiftedPlus");
+    unshiftedPlusKeyElement.setAttribute("disabled", "true");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_SWEDISH, keyCode:WIN_VK_OEM_PLUS,
+                          modifiers:{ctrlKey:1}, chars:""},
+                         "");
+    unshiftedPlusKeyElement.removeAttribute("disabled");
+  }
+
+  // bug 433192
+  if (IS_WIN) {
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_X,
+                          modifiers:{ctrlKey:1}, chars:"\u0018"},
+                         "unshiftedX");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_X,
+                          modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0018"},
+                         "shiftedX");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_ARABIC, keyCode:WIN_VK_X,
+                          modifiers:{ctrlKey:1}, chars:"\u0018"},
+                         "unshiftedX");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_ARABIC, keyCode:WIN_VK_X,
+                          modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0018"},
+                         "shiftedX");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_HEBREW, keyCode:WIN_VK_X,
+                          modifiers:{ctrlKey:1}, chars:"\u0018"},
+                         "unshiftedX");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_HEBREW, keyCode:WIN_VK_X,
+                          modifiers:{ctrlKey:1, shiftKey:1}, chars:"\u0018"},
+                         "shiftedX");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_JAPANESE, keyCode:WIN_VK_OEM_PLUS,
+                          modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                         "unshiftedPlus");
+  }
+
+  // bug 759346
+  if (IS_WIN) {
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_THAI, keyCode:WIN_VK_1,
+                          modifiers:{ctrlKey:1}, chars:""},
+                         "");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_THAI, keyCode:WIN_VK_1,
+                          modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                         "unshiftedPlus");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_THAI, keyCode:WIN_VK_OEM_PLUS,
+                          modifiers:{ctrlKey:1}, chars:""},
+                         "unshiftedPlus");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_THAI, keyCode:WIN_VK_OEM_PLUS,
+                          modifiers:{ctrlKey:1, shiftKey:1}, chars:""},
+                         "");
+  }
+
+  // bug 1596916
+  if (IS_WIN) {
+    // Ctrl + Alt + foo should be performed only when AltGr key is not
+    // pressed, i.e., only when Ctrl key and left Alt key are pressed if
+    // active keyboard layout has AltGr key.
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:WIN_VK_A,
+                          modifiers:{altGrKey:1}, chars:""},
+                         "");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:WIN_VK_A,
+                          modifiers:{ctrlKey:1, altGrKey:1}, chars:""},
+                         "");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:WIN_VK_A,
+                          modifiers:{altKey:1, altGrKey:1}, chars:""},
+                         "");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:WIN_VK_A,
+                          modifiers:{ctrlKey:1, altKey:1}, chars:""},
+                         "ctrlAltA");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:WIN_VK_A,
+                          modifiers:{ctrlKey:1, altKey:1, altGrKey:1}, chars:""},
+                         "");
+  }
+
+  // bug 1874727
+  if (IS_WIN) {
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_RUSSIAN, keyCode:WIN_VK_A,
+                          modifiers:{altKey:1, ctrlKey:1}, chars:""},
+                         "ctrlAltA");
+    yield testKeyElement({layout:KEYBOARD_LAYOUT_RUSSIAN, keyCode:WIN_VK_A,
+                          modifiers:{altKey:1, ctrlKey:1, shiftKey:1}, chars:""},
+                         "ctrlAltShiftA");
+  }
+
+  for (id in commandElements) {
+    commandElements[id].setAttribute("disabled", "true");
+  }
+  finializeKeyElementTest();
+}
+
+function* runReservedKeyTests()
+{
+  var browser = document.getElementById("browser");
+  var contents = [
+    browser.contentWindow,
+    browser.contentDocument,
+    browser.contentDocument.documentElement,
+    browser.contentDocument.body,
+    browser.contentDocument.getElementById("content_button")
+  ];
+
+  for (var i = 0; i < contents.length; i++) {
+    contents[i].addEventListener("keydown", onKeyInDefaultEventGroup, true);
+    contents[i].addEventListener("keypress", onKeyInDefaultEventGroup, true);
+    contents[i].addEventListener("keydown", onKeyInDefaultEventGroup);
+    contents[i].addEventListener("keypress", onKeyInDefaultEventGroup);
+    SpecialPowers.addSystemEventListener(contents[i], "keydown", onKeyInSystemEventGroup, true);
+    SpecialPowers.addSystemEventListener(contents[i], "keypress", onKeyInSystemEventGroup, true);
+    SpecialPowers.addSystemEventListener(contents[i], "keydown", onKeyInSystemEventGroup, false);
+    SpecialPowers.addSystemEventListener(contents[i], "keypress", onKeyInSystemEventGroup, false);
+  }
+
+  var keyEvents = [];
+
+  function onKeyInDefaultEventGroup(aDOMEvent)
+  {
+    if (isModifierKeyEvent(aDOMEvent)) {
+      return;
+    }
+    keyEvents.push({ type: aDOMEvent.type, group: "default", phase: getPhase(aDOMEvent), currentTarget: eventTargetToString(aDOMEvent.currentTarget) });
+  }
+
+  function onKeyInSystemEventGroup(aDOMEvent)
+  {
+    if (isModifierKeyEvent(aDOMEvent)) {
+      return;
+    }
+    keyEvents.push({ type: aDOMEvent.type, group: "system", phase: getPhase(aDOMEvent), currentTarget: eventTargetToString(aDOMEvent.currentTarget) });
+    // prevents reserved default action
+    if (aDOMEvent.type == "keypress" &&
+        aDOMEvent.eventPhase == aDOMEvent.BUBBLING_PHASE &&
+        aDOMEvent.currentTarget == browser.contentWindow) {
+      aDOMEvent.preventDefault();
+    }
+  }
+
+  function finializeKeyElementTest()
+  {
+    /* eslint-disable-next-line no-shadow */
+    for (var i = 0; i < contents.length; i++) {
+      contents[i].removeEventListener("keydown", onKeyInDefaultEventGroup, true);
+      contents[i].removeEventListener("keypress", onKeyInDefaultEventGroup, true);
+      contents[i].removeEventListener("keydown", onKeyInDefaultEventGroup);
+      contents[i].removeEventListener("keypress", onKeyInDefaultEventGroup);
+      SpecialPowers.removeSystemEventListener(contents[i], "keydown", onKeyInSystemEventGroup, true);
+      SpecialPowers.removeSystemEventListener(contents[i], "keypress", onKeyInSystemEventGroup, true);
+      SpecialPowers.removeSystemEventListener(contents[i], "keydown", onKeyInSystemEventGroup, false);
+      SpecialPowers.removeSystemEventListener(contents[i], "keypress", onKeyInSystemEventGroup, false);
+    }
+  }
+
+  function testReservedKey(aEvent)
+  {
+    keyEvents = [];
+    return synthesizeKey(aEvent, "content_button", function() {
+      let testName = "testReservedKey: " + eventToString(aEvent) + " ";
+      is(keyEvents.length, 20, testName + "wrong number events fired");
+      is(JSON.stringify(keyEvents[0]), JSON.stringify({ type: "keydown", group: "system", phase: "capture", currentTarget: eventTargetToString(contents[0]) }), testName + "keydown event should be fired on content only in the system event group #0");
+      is(JSON.stringify(keyEvents[1]), JSON.stringify({ type: "keydown", group: "system", phase: "capture", currentTarget: eventTargetToString(contents[1]) }), testName + "keydown event should be fired on content only in the system event group #1");
+      is(JSON.stringify(keyEvents[2]), JSON.stringify({ type: "keydown", group: "system", phase: "capture", currentTarget: eventTargetToString(contents[2]) }), testName + "keydown event should be fired on content only in the system event group #2");
+      is(JSON.stringify(keyEvents[3]), JSON.stringify({ type: "keydown", group: "system", phase: "capture", currentTarget: eventTargetToString(contents[3]) }), testName + "keydown event should be fired on content only in the system event group #3");
+
+      is(JSON.stringify(keyEvents[4]), JSON.stringify({ type: "keydown", group: "system", phase: "target", currentTarget: eventTargetToString(contents[4]) }), testName + "keydown event should be fired on content only in the system event group #4");
+      is(JSON.stringify(keyEvents[5]), JSON.stringify({ type: "keydown", group: "system", phase: "target", currentTarget: eventTargetToString(contents[4]) }), testName + "keydown event should be fired on content only in the system event group #5");
+
+      is(JSON.stringify(keyEvents[6]), JSON.stringify({ type: "keydown", group: "system", phase: "bubble", currentTarget: eventTargetToString(contents[3]) }), testName + "keydown event should be fired on content only in the system event group #6");
+      is(JSON.stringify(keyEvents[7]), JSON.stringify({ type: "keydown", group: "system", phase: "bubble", currentTarget: eventTargetToString(contents[2]) }), testName + "keydown event should be fired on content only in the system event group #7");
+      is(JSON.stringify(keyEvents[8]), JSON.stringify({ type: "keydown", group: "system", phase: "bubble", currentTarget: eventTargetToString(contents[1]) }), testName + "keydown event should be fired on content only in the system event group #8");
+      is(JSON.stringify(keyEvents[9]), JSON.stringify({ type: "keydown", group: "system", phase: "bubble", currentTarget: eventTargetToString(contents[0]) }), testName + "keydown event should be fired on content only in the system event group #9");
+
+      is(JSON.stringify(keyEvents[10]), JSON.stringify({ type: "keypress", group: "system", phase: "capture", currentTarget: eventTargetToString(contents[0]) }), testName + "keypress event should be fired on content only in the system event group #10");
+      is(JSON.stringify(keyEvents[11]), JSON.stringify({ type: "keypress", group: "system", phase: "capture", currentTarget: eventTargetToString(contents[1]) }), testName + "keypress event should be fired on content only in the system event group #11");
+      is(JSON.stringify(keyEvents[12]), JSON.stringify({ type: "keypress", group: "system", phase: "capture", currentTarget: eventTargetToString(contents[2]) }), testName + "keypress event should be fired on content only in the system event group #12");
+      is(JSON.stringify(keyEvents[13]), JSON.stringify({ type: "keypress", group: "system", phase: "capture", currentTarget: eventTargetToString(contents[3]) }), testName + "keypress event should be fired on content only in the system event group #13");
+
+      is(JSON.stringify(keyEvents[14]), JSON.stringify({ type: "keypress", group: "system", phase: "target", currentTarget: eventTargetToString(contents[4]) }), testName + "keypress event should be fired on content only in the system event group #14");
+      is(JSON.stringify(keyEvents[15]), JSON.stringify({ type: "keypress", group: "system", phase: "target", currentTarget: eventTargetToString(contents[4]) }), testName + "keypress event should be fired on content only in the system event group #15");
+
+      is(JSON.stringify(keyEvents[16]), JSON.stringify({ type: "keypress", group: "system", phase: "bubble", currentTarget: eventTargetToString(contents[3]) }), testName + "keypress event should be fired on content only in the system event group #16");
+      is(JSON.stringify(keyEvents[17]), JSON.stringify({ type: "keypress", group: "system", phase: "bubble", currentTarget: eventTargetToString(contents[2]) }), testName + "keypress event should be fired on content only in the system event group #17");
+      is(JSON.stringify(keyEvents[18]), JSON.stringify({ type: "keypress", group: "system", phase: "bubble", currentTarget: eventTargetToString(contents[1]) }), testName + "keypress event should be fired on content only in the system event group #18");
+      is(JSON.stringify(keyEvents[19]), JSON.stringify({ type: "keypress", group: "system", phase: "bubble", currentTarget: eventTargetToString(contents[0]) }), testName + "keypress event should be fired on content only in the system event group #19");
+
+      continueTest();
+    });
+  }
+
+  if (IS_MAC) {
+    // Cmd+T is reserved for opening new tab.
+    yield testReservedKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:MAC_VK_ANSI_T,
+                           modifiers:{metaKey:1}, chars:"t", unmodifiedChars:"t"});
+  } else if (IS_WIN) {
+    // Ctrl+T is reserved for opening new tab.
+    yield testReservedKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_T,
+                           modifiers:{ctrlKey:1}, chars:"\u0014"});
+    yield testReservedKey({layout:KEYBOARD_LAYOUT_ARABIC, keyCode:WIN_VK_T,
+                           modifiers:{ctrlKey:1}, chars:"\u0014"});
+  }
+
+  finializeKeyElementTest();
+}
+
+function* runTextInputTests()
+{
+  var textbox = document.getElementById("textbox");
+
+  function testKey(aEvent, aExpectText) {
+    textbox.value = "";
+    textbox.focus();
+
+    /* eslint-disable-next-line no-shadow */
+    var currentTestName = eventToString(aEvent);
+
+    // Check if the text comes with keypress events rather than composition events.
+    var keypress = 0;
+    /* eslint-disable-next-line no-shadow */
+    function onKeypress(aEvent) {
+      keypress++;
+      if (keypress == 1 && aExpectText == "") {
+        if (!aEvent.ctrlKey && !aEvent.altKey) {
+          is(aEvent.charCode, 0,
+             currentTestName + ", the charCode value should be 0 when it shouldn't cause inputting text");
+        }
+        return;
+      }
+      if (keypress > aExpectText.length) {
+        ok(false, currentTestName + " causes too many keypress events");
+        return;
+      }
+      is(aEvent.key, aExpectText[keypress - 1],
+         currentTestName + ", " + keypress + "th keypress event's key value should be '" + aExpectText[keypress - 1] + "'");
+      is(aEvent.charCode, aExpectText.charCodeAt(keypress - 1),
+         currentTestName + ", " + keypress + "th keypress event's charCode value should be 0x" + parseInt(aExpectText.charCodeAt(keypress - 1), 16));
+    }
+    textbox.addEventListener("keypress", onKeypress, true);
+
+    return synthesizeKey(aEvent, "textbox", () => {
+      textbox.removeEventListener("keypress", onKeypress, true);
+      if (aExpectText == "") {
+        if (aEvent.modifiers.ctrlKey || aEvent.modifiers.altKey) {
+          is(keypress, 1,
+             currentTestName + " should cause one keypress event because it should be available for shortcut key");
+        } else {
+          is(keypress, 0,
+             currentTestName + " should cause no keypress event because simple key press only with Shift/AltGraph " +
+               "or without any modifiers shouldn't match with a shortcut key");
+        }
+      } else {
+        is(keypress, aExpectText.length,
+           currentTestName + " should cause " + aExpectText.length + " keypress events");
+        is(textbox.value, aExpectText,
+           currentTestName + " does not input correct text.");
+      }
+
+      continueTest();
+    });
+  }
+
+  if (IS_MAC) {
+    yield testKey({layout:KEYBOARD_LAYOUT_ARABIC_PC, keyCode:MAC_VK_ANSI_G,
+                   modifiers:{shiftKey:1}, chars:"\u0644\u0623", unmodifiedChars:"\u0644\u0623"},
+                  "\u0644\u0623");
+    yield testKey({layout:KEYBOARD_LAYOUT_ARABIC_PC, keyCode:MAC_VK_ANSI_T,
+                   modifiers:{shiftKey:1}, chars:"\u0644\u0625", unmodifiedChars:"\u0644\u0625"},
+                  "\u0644\u0625");
+    yield testKey({layout:KEYBOARD_LAYOUT_ARABIC_PC, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{shiftKey:1}, chars:"\u0644\u0622", unmodifiedChars:"\u0644\u0622"},
+                  "\u0644\u0622");
+    yield testKey({layout:KEYBOARD_LAYOUT_ARABIC_PC, keyCode:MAC_VK_ANSI_B,
+                   modifiers:{}, chars:"\u0644\u0627", unmodifiedChars:"\u0644\u0627"},
+                  "\u0644\u0627");
+  } else if (IS_WIN) {
+    // Basic sanity checks
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{}, chars:"a"},
+                  "a");
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{shiftKey:1}, chars:"A"},
+                  "A");
+    // When Ctrl+Alt are pressed, any text should not be inputted.
+    yield testKey({layout:KEYBOARD_LAYOUT_EN_US, keyCode:WIN_VK_A,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:""},
+                  "");
+    // AltGr should input only when it's mapped to a character
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:WIN_VK_0,
+                   modifiers:{altGrKey:1}, chars:"}"},
+                  "}");
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:WIN_VK_A,
+                   modifiers:{altGrKey:1}, chars:""},
+                  "");
+    yield testKey({layout:KEYBOARD_LAYOUT_GERMAN, keyCode:WIN_VK_A,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:""},
+                  "");
+
+    // Lithuanian AltGr should be consumed at 9/0 keys pressed
+    yield testKey({layout:KEYBOARD_LAYOUT_LITHUANIAN, keyCode:WIN_VK_8,
+                   modifiers:{}, chars:"\u016B"},
+                  "\u016B");
+    yield testKey({layout:KEYBOARD_LAYOUT_LITHUANIAN, keyCode:WIN_VK_9,
+                   modifiers:{}, chars:"9"},
+                  "9");
+    yield testKey({layout:KEYBOARD_LAYOUT_LITHUANIAN, keyCode:WIN_VK_0,
+                   modifiers:{}, chars:"0"},
+                  "0");
+    yield testKey({layout:KEYBOARD_LAYOUT_LITHUANIAN, keyCode:WIN_VK_8,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"8"},
+                  "8");
+    yield testKey({layout:KEYBOARD_LAYOUT_LITHUANIAN, keyCode:WIN_VK_9,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"9"},
+                  "9");
+    yield testKey({layout:KEYBOARD_LAYOUT_LITHUANIAN, keyCode:WIN_VK_0,
+                   modifiers:{ctrlKey:1, altKey:1}, chars:"0"},
+                  "0");
+  }
+
+  // XXX We need to move focus for canceling to search the autocomplete
+  // result. If we don't do here, Fx will crash at end of this tests.
+  document.getElementById("button").focus();
+}
+
+function* runAltRightKeyOnWindows()
+{
+  if (!IS_WIN) {
+    return;
+  }
+
+  var button = document.getElementById("button");
+  button.focus();
+
+  const kKeyboardLayouts = [
+    { layout: KEYBOARD_LAYOUT_ARABIC },
+    { layout: KEYBOARD_LAYOUT_BRAZILIAN_ABNT },
+    { layout: KEYBOARD_LAYOUT_EN_US },
+    { layout: KEYBOARD_LAYOUT_FRENCH },
+    { layout: KEYBOARD_LAYOUT_GREEK },
+    { layout: KEYBOARD_LAYOUT_GERMAN },
+    { layout: KEYBOARD_LAYOUT_HEBREW },
+    { layout: KEYBOARD_LAYOUT_JAPANESE },
+    { layout: KEYBOARD_LAYOUT_KHMER },
+    { layout: KEYBOARD_LAYOUT_LITHUANIAN },
+    { layout: KEYBOARD_LAYOUT_NORWEGIAN },
+    { layout: KEYBOARD_LAYOUT_RUSSIAN_MNEMONIC,
+      canTestIt () { return OS_VERSION >= WIN8; } },
+    { layout: KEYBOARD_LAYOUT_SPANISH },
+    { layout: KEYBOARD_LAYOUT_SWEDISH },
+    { layout: KEYBOARD_LAYOUT_THAI },
+  ];
+  var events = [];
+  function pushEvent(aEvent) {
+    events.push(aEvent);
+    if (aEvent.key === "Alt") {
+      // Prevent working the menubar.
+      aEvent.preventDefault();
+    }
+  }
+  button.addEventListener("keydown", pushEvent);
+  button.addEventListener("keyup", pushEvent);
+
+  function testKey(aKeyboardLayout) {
+    return synthesizeKey({layout: aKeyboardLayout.layout, keyCode: WIN_VK_RMENU,
+                          modifiers: {}, chars: ""}, "button", function() {
+      const kDescription =
+        "runAltRightKeyOnWindows(" + aKeyboardLayout.layout.currentTestName + "): ";
+      if (aKeyboardLayout.layout.hasAltGrOnWin) {
+        is(events.length, 4,
+           kDescription + "AltRight should fire 2 pairs of keydown and keyup events");
+        is(events[0].type, "keydown",
+           kDescription + "First event should be keydown of ControlLeft");
+        is(events[0].key, "Control",
+           kDescription + "First event should be keydown of ControlLeft whose key should be Control");
+        is(events[0].code, "ControlLeft",
+           kDescription + "First event should be keydown of ControlLeft");
+        is(events[0].location, KeyboardEvent.DOM_KEY_LOCATION_LEFT,
+           kDescription + "First event should be keydown of ControlLeft whose location should be DOM_KEY_LOCATION_LEFT");
+        is(events[0].keyCode, KeyboardEvent.DOM_VK_CONTROL,
+           kDescription + "First event should be keydown of ControlLeft whose keyCode should be DOM_VK_CONTROL");
+        is(events[0].ctrlKey, true,
+           kDescription + "First event should be keydown of ControlLeft whose ctrlKey should be true");
+        is(events[0].altKey, false,
+           kDescription + "First event should be keydown of ControlLeft whose altKey should be false");
+        is(events[0].getModifierState("AltGraph"), false,
+           kDescription + "First event should be keydown of ControlLeft whose getModifierState(\"AltGraph\") should be false");
+        is(events[1].type, "keydown",
+           kDescription + "Second event should be keydown of AltRight");
+        is(events[1].key, "AltGraph",
+           kDescription + "Second event should be keydown of AltRight whose key should be AltGraph");
+        is(events[1].code, "AltRight",
+           kDescription + "Second event should be keydown of AltRight");
+        is(events[1].location, KeyboardEvent.DOM_KEY_LOCATION_RIGHT,
+           kDescription + "Second event should be keydown of AltRight whose location should be DOM_KEY_LOCATION_RIGHT");
+        is(events[1].keyCode, KeyboardEvent.DOM_VK_ALT,
+           kDescription + "Second event should be keydown of AltRight whose keyCode should be DOM_VK_ALT");
+        is(events[1].ctrlKey, false,
+           kDescription + "Second event should be keydown of AltRight whose ctrlKey should be false");
+        is(events[1].altKey, false,
+           kDescription + "Second event should be keydown of AltRight whose altKey should be false");
+        is(events[1].getModifierState("AltGraph"), true,
+           kDescription + "Second event should be keydown of AltRight whose getModifierState(\"AltGraph\") should be true");
+        is(events[2].type, "keyup",
+           kDescription + "Third event should be keyup of ControlLeft");
+        is(events[2].key, "Control",
+           kDescription + "Third event should be keyup of ControlLeft whose key should be Control");
+        is(events[2].code, "ControlLeft",
+           kDescription + "Third event should be keyup of ControlLeft");
+        is(events[2].location, KeyboardEvent.DOM_KEY_LOCATION_LEFT,
+           kDescription + "Third event should be keyup of ControlLeft whose location should be DOM_KEY_LOCATION_LEFT");
+        is(events[2].keyCode, KeyboardEvent.DOM_VK_CONTROL,
+           kDescription + "Third event should be keyup of ControlLeft whose keyCode should be DOM_VK_CONTROL");
+        is(events[2].ctrlKey, false,
+           kDescription + "Third event should be keyup of ControlLeft whose ctrlKey should be false");
+        is(events[2].altKey, false,
+           kDescription + "Third event should be keyup of ControlLeft whose altKey should be false");
+        is(events[2].getModifierState("AltGraph"), true,
+           kDescription + "Third event should be keyup of ControlLeft whose getModifierState(\"AltGraph\") should be true");
+        is(events[3].type, "keyup",
+           kDescription + "Forth event should be keyup of AltRight");
+        is(events[3].key, "AltGraph",
+           kDescription + "Forth event should be keyup of AltRight whose key should be AltGraph");
+        is(events[3].code, "AltRight",
+           kDescription + "Forth event should be keyup of AltRight");
+        is(events[3].location, KeyboardEvent.DOM_KEY_LOCATION_RIGHT,
+           kDescription + "Forth event should be keyup of AltRight whose location should be DOM_KEY_LOCATION_RIGHT");
+        is(events[3].keyCode, KeyboardEvent.DOM_VK_ALT,
+           kDescription + "Forth event should be keyup of AltRight whose keyCode should be DOM_VK_ALT");
+        is(events[3].ctrlKey, false,
+           kDescription + "Third event should be keyup of AltRight whose ctrlKey should be false");
+        is(events[3].altKey, false,
+           kDescription + "Third event should be keyup of AltRight whose altKey should be false");
+        is(events[3].getModifierState("AltGraph"), false,
+           kDescription + "Third event should be keyup of AltRight whose getModifierState(\"AltGraph\") should be false");
+      } else {
+        is(events.length, 2,
+           kDescription + "AltRight should fire a pair of keydown and keyup events");
+        is(events[0].type, "keydown",
+           kDescription + "First event should be keydown of AltRight");
+        is(events[0].key, "Alt",
+           kDescription + "First event should be keydown of AltRight whose key should be Alt");
+        is(events[0].code, "AltRight",
+           kDescription + "First event should be keydown of AltRight");
+        is(events[0].location, KeyboardEvent.DOM_KEY_LOCATION_RIGHT,
+           kDescription + "First event should be keydown of AltRight whose location should be DOM_KEY_LOCATION_RIGHT");
+        is(events[0].keyCode, KeyboardEvent.DOM_VK_ALT,
+           kDescription + "First event should be keydown of AltRight whose keyCode should be DOM_VK_ALT");
+        is(events[0].ctrlKey, false,
+           kDescription + "First event should be keydown of AltRight whose ctrlKey should be false");
+        is(events[0].altKey, true,
+           kDescription + "First event should be keydown of AltRight whose altKey should be true");
+        is(events[0].getModifierState("AltGraph"), false,
+           kDescription + "First event should be keydown of AltRight whose getModifierState(\"AltGraph\") should be false");
+        is(events[1].type, "keyup",
+           kDescription + "Second event should be keyup of AltRight");
+        is(events[1].key, "Alt",
+           kDescription + "Second event should be keyup of AltRight whose key should be Alt");
+        is(events[1].code, "AltRight",
+           kDescription + "Second event should be keyup of AltRight");
+        is(events[1].location, KeyboardEvent.DOM_KEY_LOCATION_RIGHT,
+           kDescription + "Second event should be keyup of AltRight whose location should be DOM_KEY_LOCATION_RIGHT");
+        is(events[1].keyCode, KeyboardEvent.DOM_VK_ALT,
+           kDescription + "Second event should be keyup of AltRight whose keyCode should be DOM_VK_ALT");
+        is(events[1].ctrlKey, false,
+           kDescription + "Second event should be keyup of AltRight whose ctrlKey should be false");
+        is(events[1].altKey, false,
+           kDescription + "Second event should be keyup of AltRight whose altKey should be false");
+        is(events[1].getModifierState("AltGraph"), false,
+           kDescription + "Second event should be keyup of AltRight whose getModifierState(\"AltGraph\") should be false");
+      }
+
+      continueTest();
+    });
+  }
+
+  for (const kKeyboardLayout of kKeyboardLayouts) {
+    if (typeof kKeyboardLayout.canTestIt === "function" &&
+        !kKeyboardLayout.canTestIt()) {
+      continue;
+    }
+    events = [];
+    yield testKey(kKeyboardLayout);
+  }
+
+  button.addEventListener("keydown", pushEvent);
+  button.addEventListener("keyup", pushEvent);
+}
+
+function* runAllTests() {
+  yield* runKeyEventTests();
+  yield* runAccessKeyTests();
+  yield* runXULKeyTests();
+  yield* runReservedKeyTests();
+  yield* runTextInputTests();
+  yield* runAltRightKeyOnWindows();
+}
+
+var gTestContinuation = null;
+
+function continueTest()
+{
+  if (!gTestContinuation) {
+    gTestContinuation = runAllTests();
+  }
+  var ret = gTestContinuation.next();
+  if (ret.done) {
+    SimpleTest.finish();
+  } else {
+    is(ret.value, true, "Key synthesized successfully");
+  }
+}
+
+function runTest()
+{
+  if (!IS_MAC && !IS_WIN) {
+    todo(false, "This test is supported on MacOSX and Windows only. (Bug 431503)");
+    return;
+  }
+
+  if (IS_WIN && OS_VERSION >= WIN8) {
+    // Switching keyboard layout to Russian - Mnemonic causes 2 assertions in
+    // KeyboardLayout::LoadLayout().
+    const kAssertionCountDueToRussainMnemonic = 2 * 2;
+    SimpleTest.expectAssertions(kAssertionCountDueToRussainMnemonic,
+                                kAssertionCountDueToRussainMnemonic);
+  }
+  SimpleTest.waitForExplicitFinish();
+
+  clearInfobars();
+
+  continueTest();
+}
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_keypress_event_with_alt_on_mac.html b/widget/tests/test_keypress_event_with_alt_on_mac.html
new file mode 100644
index 0000000000..01d4100f97
--- /dev/null
+++ b/widget/tests/test_keypress_event_with_alt_on_mac.html
@@ -0,0 +1,106 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Testing if keypress event is fired when alt key is pressed</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="/tests/SimpleTest/EventUtils.js"></script>
+  <script src="/tests/SimpleTest/NativeKeyCodes.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css">
+</head>
+<body>
+<div id="display">
+  <input id="input">
+  <input id="password" type="password">
+  <input id="readonly-input" readonly>
+  <textarea id="textarea"></textarea>
+  <textarea id="readonly-textarea" readonly></textarea>
+  <button id="button">button</button>
+</div>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+</pre>
+
+<script class="testbody" type="application/javascript">
+SimpleTest.waitForExplicitFinish();
+
+async function testNativeKey(aKeyboardLayout, aNativeKeyCode, aModifiers,
+                             aChars, aUnmodifiedChars) {
+  // XXX Need to listen keyup event here because synthesizeNativeKey() does not
+  //     guarantee that its callback will be called after "keypress" and "keyup".
+  let waitForKeyUp = new Promise(resolve => {
+    document.addEventListener("keyup", resolve, {once: true});
+  });
+  let keypress;
+  document.addEventListener("keypress", (aKeyPressEvent) => {
+    keypress = aKeyPressEvent;
+  }, {once: true});
+  synthesizeNativeKey(aKeyboardLayout, aNativeKeyCode, aModifiers, aChars, aUnmodifiedChars);
+  await waitForKeyUp;
+  return keypress;
+}
+
+async function runTests() {
+  const kTests =
+    [ { target: "input", isEditable: true },
+      { target: "password", isEditable: true },
+      { target: "readonly-input", isEditable: false },
+      { target: "textarea", isEditable: true },
+      { target: "readonly-textarea", isEditable: false },
+      { target: "button", isEditable: false } ];
+  for (const kTest of kTests) {
+    let element = document.getElementById(kTest.target);
+    element.focus();
+
+    const kDescription = kTest.target + ": ";
+
+    let keypress = await testNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_A, {}, "a", "a");
+    ok(keypress,
+       kDescription + "'a' key press should cause firing keypress event");
+
+    keypress = await testNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_A, {shiftKey: true}, "A", "A");
+    ok(keypress,
+       kDescription + "'a' key press with shift key should cause firing keypress event");
+    ok(keypress.shiftKey,
+       kDescription + "shiftKey of 'a' key press with shift key should be true");
+
+    // When a key inputs a character with option key, we need to unset altKey for our editor.
+    // Otherwise, altKey should be true for compatibility with the other browsers.
+    keypress = await testNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_A, {altKey: true}, "\u00E5", "a");
+    ok(keypress,
+       kDescription + "'a' key press with option key should cause firing keypress event");
+    is(keypress.altKey, !kTest.isEditable,
+       kDescription + "altKey of 'a' key press with option key should be " + !kTest.isEditable);
+
+    keypress = await testNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_A, {altKey: true, shiftKey: true}, "\u00C5", "A");
+    ok(keypress,
+       kDescription + "'a' key press with option key  and shift key should cause firing keypress event");
+    is(keypress.altKey, !kTest.isEditable,
+       kDescription + "altKey of 'a' key press with option key and shift key should be " + !kTest.isEditable);
+    ok(keypress.shiftKey,
+       kDescription + "shiftKey of 'a' key press with option key and shift key should be true");
+
+    keypress = await testNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_A, {ctrlKey: true}, "\u0001", "a");
+    ok(!keypress,
+       kDescription + "'a' key press with control key should not cause firing keypress event");
+
+    keypress = await testNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_A, {altKey: true, ctrlKey: true}, "\u0001", "a");
+    ok(!keypress,
+       kDescription + "'a' key press with option key and control key should not cause firing keypress event");
+
+    // XXX Cannot test with command key for now since keyup event won't be fired due to macOS's limitation.
+
+    // Some keys of Arabic - PC keyboard layout do not input any character with option key.
+    // In such case, we shouldn't dispatch keypress event.
+    keypress = await testNativeKey(KEYBOARD_LAYOUT_ARABIC_PC, MAC_VK_ANSI_7, {altKey: true}, "", "\u0667");
+    ok(!keypress,
+       kDescription + "'7' key press with option key should not cause firing keypress event");
+  }
+
+  SimpleTest.finish();
+}
+
+SimpleTest.waitForFocus(runTests);
+</script>
+</body>
+</html>
\ No newline at end of file
diff --git a/widget/tests/test_mouse_event_with_control_on_mac.html b/widget/tests/test_mouse_event_with_control_on_mac.html
new file mode 100644
index 0000000000..52ce206d35
--- /dev/null
+++ b/widget/tests/test_mouse_event_with_control_on_mac.html
@@ -0,0 +1,116 @@
+<html>
+<head>
+  <title>Test control+click on Mac</title>
+  <script src="/tests/SimpleTest/EventUtils.js"></script>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="/tests/SimpleTest/SpecialPowers.js"></script>
+  <script src="/tests/SimpleTest/paint_listener.js"></script>
+  <script src="/tests/gfx/layers/apz/test/mochitest/apz_test_utils.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css">
+  <style>
+    #target {
+      width: 100px;
+      height: 100px;
+      background-color: lightgreen;
+    };
+  </style>
+</head>
+<body>
+<div id="target"></div>
+<script type="application/javascript">
+
+function waitAndCheckMouseEvents(aTarget, aExpectedEvents) {
+  return new Promise((aResolve, aReject) => {
+    let timer;
+    let cleanup = function() {
+      if (timer) {
+        clearTimeout(timer);
+        timer = null;
+      }
+      aTarget.removeEventListener("mousedown", listener);
+      aTarget.removeEventListener("mouseup", listener);
+      aTarget.removeEventListener("contextmenu", listener);
+      aTarget.removeEventListener("click", listener);
+      aTarget.removeEventListener("auxclick", listener);
+    };
+
+    let listener = function(aEvent) {
+      aEvent.preventDefault();
+      let expectedEvent = aExpectedEvents.shift();
+      if (!expectedEvent) {
+        cleanup();
+        ok(false, `receive unexpected ${aEvent.type} event`);
+        aReject(new Error(`receive unexpected ${aEvent.type} event`));
+        return;
+      }
+
+      isDeeply([aEvent.type, aEvent.button, aEvent.ctrlKey], expectedEvent,
+               `check received ${aEvent.type} event`);
+      if (!aExpectedEvents.length) {
+        // Wait a bit to see if there is any unexpected event.
+        timer = setTimeout(function() {
+          cleanup();
+          aResolve();
+        }, 0);
+      }
+    };
+
+    aTarget.addEventListener("mousedown", listener);
+    aTarget.addEventListener("mouseup", listener);
+    aTarget.addEventListener("contextmenu", listener);
+    aTarget.addEventListener("click", listener);
+    aTarget.addEventListener("auxclick", listener);
+  });
+}
+
+add_task(async function Init() {
+  await SimpleTest.promiseFocus();
+  await waitUntilApzStable();
+
+  let target = document.getElementById("target");
+  target.addEventListener("click", function() {
+    ok(false, `should not receive click event`);
+  });
+});
+
+add_task(async function TestMouseClickWithControl() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["dom.event.treat_ctrl_click_as_right_click.disabled", true]],
+  });
+
+  let target = document.getElementById("target");
+  let promise = waitAndCheckMouseEvents(target, [["mousedown", 0, true],
+                                                 ["contextmenu", 0, true],
+                                                 ["mouseup", 0, true]]);
+  synthesizeNativeMouseEvent({
+    type: "click",
+    target,
+    offsetX: 10,
+    offsetY: 10,
+    modifiers: { ctrlKey: true },
+  });
+  await promise;
+});
+
+add_task(async function TestOldBehavior() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["dom.event.treat_ctrl_click_as_right_click.disabled", false]],
+  });
+
+  let target = document.getElementById("target");
+  let promise = waitAndCheckMouseEvents(target, [["mousedown", 2, true],
+                                                 ["contextmenu", 2, true],
+                                                 ["mouseup", 2, true],
+                                                 ["auxclick", 2, true]]);
+  synthesizeNativeMouseEvent({
+    type: "click",
+    target,
+    offsetX: 10,
+    offsetY: 10,
+    modifiers: { ctrlKey: true },
+  });
+  await promise;
+});
+</script>
+</body>
+</html>
diff --git a/widget/tests/test_mouse_scroll.xhtml b/widget/tests/test_mouse_scroll.xhtml
new file mode 100644
index 0000000000..82cb6a3ea3
--- /dev/null
+++ b/widget/tests/test_mouse_scroll.xhtml
@@ -0,0 +1,35 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Testing composition, text and query content events"
+  onload="setTimeout(onLoad, 0);"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+function onLoad()
+{
+  runTest();
+}
+
+function runTest()
+{
+  window.openDialog("window_mouse_scroll_win.html", "_blank",
+                    "chrome,width=600,height=600,noopener", window);
+}
+]]>
+</script>
+</window>
diff --git a/widget/tests/test_native_key_bindings_mac.html b/widget/tests/test_native_key_bindings_mac.html
new file mode 100644
index 0000000000..8767a5a77d
--- /dev/null
+++ b/widget/tests/test_native_key_bindings_mac.html
@@ -0,0 +1,336 @@
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <meta charset='utf-8'/>
+    <title>Native Key Bindings for Cocoa Test</title>
+    <!-- Any copyright is dedicated to the Public Domain.
+         http://creativecommons.org/publicdomain/zero/1.0/ -->
+    <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+    <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"></script>
+    <script src="chrome://mochikit/content/tests/SimpleTest/NativeKeyCodes.js"></script>
+  </head>
+  <body>
+    <div id="editable" contenteditable>
+      <p>Stretching attack nullam stuck in a tree zzz, suspendisse cras nec
+      suspendisse lick suscipit. Nunc egestas amet litter box, nullam climb the
+      curtains biting I don't like that food tristique biting sleep on your
+      keyboard non. Lay down in your way cras nec tempus chase the red dot cras
+      nec, pharetra pharetra eat the grass leap run orci turpis attack.
+      Consectetur sleep in the sink eat I don't like that food, knock over the
+      lamp catnip in viverra tail flick zzz meow etiam enim. Ac ac hiss shed
+      everywhere kittens rhoncus, attack your ankles zzz iaculis kittens. Nullam
+      pellentesque rip the couch iaculis rhoncus nibh, give me fish orci turpis
+      purr sleep on your face quis nunc bibendum.</p>
+
+      <p>Neque jump on the table bat iaculis, adipiscing sleep on your keyboard
+      jump vel justo shed everywhere suspendisse lick. Zzz enim faucibus
+      hairball faucibus, pharetra sunbathe biting bat leap rip the couch attack.
+      Tortor nibh in viverra quis hairball nam, vulputate adipiscing sleep on
+      your keyboard purr knock over the lamp orci turpis. Vestibulum I don't
+      like that food et chase the red dot, adipiscing neque bibendum rutrum
+      accumsan quis rhoncus claw. Leap accumsan vehicula enim biting sleep on
+      your face, pharetra nam accumsan egestas kittens sunbathe. Pharetra chase
+      the red dot sniff non eat the grass, vulputate fluffy fur aliquam puking
+      judging you.</p>
+
+      <p>Claw purr sollicitudin sollicitudin lay down in your way consectetur,
+      pellentesque vehicula zzz orci turpis consectetur. I don't like that food
+      rhoncus pellentesque sniff attack, rhoncus tortor attack your ankles
+      iaculis scratched hiss vel. Tortor zzz tortor nullam rip the couch rutrum,
+      bat enim ut leap hairball iaculis. Bibendum sunbathe elit suspendisse
+      nibh, puking adipiscing sleep on your face sleep on your face zzz catnip.
+      Judging you rutrum bat sunbathe sleep on your face, jump on the table leap
+      tincidunt a faucibus sleep in the sink. Stuck in a tree tristique zzz hiss
+      in viverra nullam, quis tortor pharetra attack.</p>
+    </div>
+
+    <textarea id="textarea" cols="80">
+      Stretching attack nullam stuck in a tree zzz, suspendisse cras nec
+      suspendisse lick suscipit. Nunc egestas amet litter box, nullam climb the
+      curtains biting I don't like that food tristique biting sleep on your
+      keyboard non. Lay down in your way cras nec tempus chase the red dot cras
+      nec, pharetra pharetra eat the grass leap run orci turpis attack.
+      Consectetur sleep in the sink eat I don't like that food, knock over the
+      lamp catnip in viverra tail flick zzz meow etiam enim. Ac ac hiss shed
+      everywhere kittens rhoncus, attack your ankles zzz iaculis kittens. Nullam
+      pellentesque rip the couch iaculis rhoncus nibh, give me fish orci turpis
+      purr sleep on your face quis nunc bibendum.
+
+      Neque jump on the table bat iaculis, adipiscing sleep on your keyboard
+      jump vel justo shed everywhere suspendisse lick. Zzz enim faucibus
+      hairball faucibus, pharetra sunbathe biting bat leap rip the couch attack.
+      Tortor nibh in viverra quis hairball nam, vulputate adipiscing sleep on
+      your keyboard purr knock over the lamp orci turpis. Vestibulum I don't
+      like that food et chase the red dot, adipiscing neque bibendum rutrum
+      accumsan quis rhoncus claw. Leap accumsan vehicula enim biting sleep on
+      your face, pharetra nam accumsan egestas kittens sunbathe. Pharetra chase
+      the red dot sniff non eat the grass, vulputate fluffy fur aliquam puking
+      judging you.
+
+      Claw purr sollicitudin sollicitudin lay down in your way consectetur,
+      pellentesque vehicula zzz orci turpis consectetur. I don't like that food
+      rhoncus pellentesque sniff attack, rhoncus tortor attack your ankles
+      iaculis scratched hiss vel. Tortor zzz tortor nullam rip the couch rutrum,
+      bat enim ut leap hairball iaculis. Bibendum sunbathe elit suspendisse
+      nibh, puking adipiscing sleep on your face sleep on your face zzz catnip.
+      Judging you rutrum bat sunbathe sleep on your face, jump on the table leap
+      tincidunt a faucibus sleep in the sink. Stuck in a tree tristique zzz hiss
+      in viverra nullam, quis tortor pharetra attack.
+    </textarea>
+
+    <input id="input" type="text"
+      value="Stretching attack nullam stuck in a tree zzz, suspendisse cras nec
+      suspendisse lick suscipit. Nunc egestas amet litter box, nullam climb the
+      curtains biting I don't like that food tristique biting sleep on your
+      keyboard non. Lay down in your way cras nec tempus chase the red dot cras
+      nec, pharetra pharetra eat the grass leap run orci turpis attack.
+      Consectetur sleep in the sink eat I don't like that food, knock over the
+      lamp catnip in viverra tail flick zzz meow etiam enim. Ac ac hiss shed
+      everywhere kittens rhoncus, attack your ankles zzz iaculis kittens.
+      Nullam pellentesque rip the couch iaculis rhoncus nibh, give me fish orci
+      turpis purr sleep on your face quis nunc bibendum.">
+
+    <script type="text/javascript">
+      SimpleTest.waitForExplicitFinish();
+
+      let synthesizedKeys = [];
+      let expectations = [];
+
+      // Move to beginning of line
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_LeftArrow,
+                            {ctrlKey: true}, "\uf702", "\uf702"]);
+      expectations.push({
+        editable: [0, 0],
+        textarea: [0, 0],
+        input:    [0, 0],
+      });
+
+      // Move to end of line
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_RightArrow,
+                            {ctrlKey: true}, "\uf703", "\uf703"]);
+      expectations.push({
+        editable: [73, 73],
+        textarea: [72, 72],
+        input:    [732, 732],
+      });
+
+      // Move down
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_N,
+                            {ctrlKey: true}, "\u000e", "n"]);
+      expectations.push({
+        editable: [140, 140],
+        textarea: [145, 145],
+        input:    [732, 732],
+      });
+
+      // Move to beginning of line
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_LeftArrow,
+                            {ctrlKey: true}, "\uf702", "\uf702"]);
+      expectations.push({
+        editable: [73, 73],
+        textarea: [73, 73],
+        input:    [0, 0],
+      });
+
+      // Move word right and modify selection
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_RightArrow,
+                            {altKey: true, shiftKey: true}, "\uf703", "\uf703"]);
+      expectations.push({
+        editable: [73, 84],
+        textarea: [73, 90],
+        input:    [0, 10],
+      });
+
+      // Move word right
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_RightArrow,
+                            {altKey: true}, "\uf703", "\uf703"]);
+      expectations.push({
+        editable: [84, 84],
+        textarea: [90, 90],
+        input:    [10, 10],
+      });
+
+      // Move word right
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_RightArrow,
+                            {altKey: true}, "\uf703", "\uf703"]);
+      expectations.push({
+        editable: [89, 89],
+        textarea: [95, 95],
+        input:    [17, 17],
+      });
+
+      // Move down and modify selection
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_DownArrow,
+                            {shiftKey: true}, "\uf701", "\uf701"]);
+      expectations.push({
+        editable: [89, 171],
+        textarea: [95, 175],
+        input:    [17, 732],
+      });
+
+      // Move backward and modify selection
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_B,
+                            {ctrlKey: true, shiftKey: true}, "\u0002", "B"]);
+      expectations.push({
+        editable: [89, 170],
+        textarea: [95, 174],
+        input:    [17, 731],
+      });
+
+      // Delete forward
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_D,
+                            {ctrlKey: true}, "\u0004", "d"]);
+      expectations.push({
+        editable: [89, 89],
+        textarea: [95, 95],
+        input:    [17, 17],
+      });
+
+      // Delete backward
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_H,
+                            {ctrlKey: true}, "\u0008", "h"]);
+      expectations.push({
+        editable: [88, 88],
+        textarea: [94, 94],
+        input:    [16, 16],
+      });
+
+      // Move backward
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_B,
+                            {ctrlKey: true}, "\u0002", "b"]);
+      expectations.push({
+        editable: [87, 87],
+        textarea: [93, 93],
+        input:    [15, 15],
+      });
+
+      // Move to beginning of paragraph (line for now)
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_A,
+                            {ctrlKey: true}, "\u0001", "a"]);
+      expectations.push({
+        editable: [73, 73],
+        textarea: [73, 73],
+        input:    [0, 0],
+      });
+
+      // Move forward
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_F,
+                            {ctrlKey: true}, "\u0006", "f"]);
+      expectations.push({
+        editable: [74, 74],
+        textarea: [74, 74],
+        input:    [1, 1],
+      });
+
+      // Move word right
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_RightArrow,
+                            {altKey: true}, "\uf703", "\uf703"]);
+      expectations.push({
+        editable: [84, 84],
+        textarea: [90, 90],
+        input:    [10, 10],
+      });
+
+      // Move word right
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_RightArrow,
+                            {altKey: true}, "\uf703", "\uf703"]);
+      expectations.push({
+        editable: [88, 88],
+        textarea: [94, 94],
+        input:    [17, 17],
+      });
+
+      // Delete to end of paragraph (line for now)
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_K,
+                            {ctrlKey: true}, "\u000b", "k"]);
+      expectations.push({
+        editable: [88, 88],
+        textarea: [94, 94],
+        input:    [17, 17],
+      });
+
+      // Move backward and modify selection
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_B,
+                            {ctrlKey: true, shiftKey: true}, "\u0002", "B"]);
+      expectations.push({
+        editable: [88, 87],
+        textarea: [93, 94],
+        input:    [16, 17],
+      });
+
+      // Move to end of paragraph (line for now)
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_E,
+                            {ctrlKey: true}, "\u0005", "e"]);
+      expectations.push({
+        editable: [139, 139],
+        textarea: [94, 94],
+        input:    [17, 17],
+      });
+
+      // Move up
+      synthesizedKeys.push([KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_P,
+                            {ctrlKey: true}, "\u0010", "p"]);
+      expectations.push({
+        editable: [73, 73],
+        textarea: [21, 21],
+        input:    [0, 0],
+      });
+
+      function checkWindowSelection(aElement, aSelection) {
+        let selection = window.getSelection();
+
+        is(selection.anchorOffset, aSelection[aElement.id][0],
+           aElement.id + ": Incorrect anchor offset");
+        is(selection.focusOffset, aSelection[aElement.id][1],
+           aElement.id + ": Incorrect focus offset");
+      }
+
+      function checkElementSelection(aElement, aSelection) {
+        is(aElement.selectionStart, aSelection[aElement.id][0],
+           aElement.id + ": Incorrect selection start");
+        is(aElement.selectionEnd, aSelection[aElement.id][1],
+           aElement.id + ": Incorrect selection end");
+      }
+
+      function* testRun(aElement, aSelectionCheck, aCallback) {
+        if (document.activeElement) {
+          document.activeElement.blur();
+        }
+
+        aElement.focus();
+
+        for (let i = 0; i < synthesizedKeys.length; i++) {
+          synthesizedKeys[i].push(function() {
+            aSelectionCheck(aElement, expectations[i]);
+            continueTest();
+          });
+          var synthOk = synthesizeNativeKey.apply(null, synthesizedKeys[i]);
+          synthesizedKeys[i].pop();
+          yield synthOk;
+        }
+      }
+
+      function* doTest() {
+        yield* testRun(document.getElementById("editable"), checkWindowSelection);
+        yield* testRun(document.getElementById("textarea"), checkElementSelection);
+        yield* testRun(document.getElementById("input"), checkElementSelection);
+      }
+
+      let gTestContinuation = null;
+
+      function continueTest() {
+        if (!gTestContinuation) {
+          gTestContinuation = doTest();
+        }
+        var ret = gTestContinuation.next();
+        if (ret.done) {
+          SimpleTest.finish();
+        } else {
+          is(ret.value, true, "Successfully synthesized key");
+        }
+      }
+
+      SimpleTest.waitForFocus(continueTest);
+    </script>
+  </body>
+</html>
diff --git a/widget/tests/test_native_menus.xhtml b/widget/tests/test_native_menus.xhtml
new file mode 100644
index 0000000000..d62c57f21c
--- /dev/null
+++ b/widget/tests/test_native_menus.xhtml
@@ -0,0 +1,29 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Native menu system tests"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+window.openDialog("native_menus_window.xhtml", "NativeMenuWindow", 
+                  "chrome,width=600,height=600,noopener", window);
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_panel_mouse_coords.xhtml b/widget/tests/test_panel_mouse_coords.xhtml
new file mode 100644
index 0000000000..43c4e10249
--- /dev/null
+++ b/widget/tests/test_panel_mouse_coords.xhtml
@@ -0,0 +1,78 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=835044
+-->
+<window title="Mozilla Bug 835044"
+        onload="startTest()"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"/>
+
+<panel id="thepanel" level="parent"
+       onpopupshown="sendMouseEvent();"
+       onmousemove="checkCoords(event);"
+       style="width: 80px; height: 80px">
+</panel>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+  <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=835044"
+     id="anchor"
+     target="_blank">Mozilla Bug 835044</a>
+  </body>
+
+  <!-- test code goes here -->
+  <script type="application/javascript">
+  <![CDATA[
+SimpleTest.waitForExplicitFinish();
+
+let panel = document.getElementById('thepanel');
+let rect = null;
+
+
+function startTest() {
+  // This first event is to ensure that the next event will have different
+  // coordinates to the previous mouse position, and so actually generates
+  // mouse events.  The mouse is not moved off the window, as that might
+  // move focus to another application.
+  synthesizeNativeMouseEvent({
+    type: "mousemove",
+    screenX: window.mozInnerScreenX,
+    screenY: window.mozInnerScreenY,
+    elementOnWidget: window.documentElement,
+  });
+
+  panel.openPopup(document.getElementById("anchor"), "after_start");
+}
+
+function sendMouseEvent() {
+  rect = panel.getBoundingClientRect();
+  synthesizeNativeMouseEvent({
+    type: "mousemove",
+    target: panel,
+    offsetX: 10,
+    offsetY: 20,
+  });
+}
+
+function checkCoords(event) {
+  if (!rect) {
+    return;
+  }
+  isfuzzy(event.clientX, rect.left + 10, window.devicePixelRatio, "Motion x coordinate");
+  isfuzzy(event.clientY, rect.top + 20, window.devicePixelRatio, "Motion y coordinate");
+  info(`Event client: ${event.clientX}, ${event.clientY}, panel client: ${rect.left}, ${rect.top}`);
+  info(`Event screen: ${event.screenX}, ${event.screenY}, panel screen: ${panel.screenX}, ${panel.screenY}`);
+  info(`offset client: ${event.clientX - rect.left}, ${event.clientY - rect.top}`);
+  info(`offset screen: ${event.screenX - panel.screenX}, ${event.screenY - panel.screenY}`);
+  done();
+}
+
+function done() {
+  SimpleTest.finish();
+}
+  ]]>
+  </script>
+</window>
diff --git a/widget/tests/test_picker_no_crash.html b/widget/tests/test_picker_no_crash.html
new file mode 100644
index 0000000000..dbb75627b5
--- /dev/null
+++ b/widget/tests/test_picker_no_crash.html
@@ -0,0 +1,30 @@
+<!DOCTYPE HTML>
+<title>Test for crashes when the parent window of a file picker is closed via script</title>
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<script src="/tests/SimpleTest/EventUtils.js"></script>
+<link rel="stylesheet" href="/tests/SimpleTest/test.css"/>
+<script>
+SimpleTest.requestFlakyTimeout("testing we don't crash");
+
+async function testPicker(id) {
+  let childWindow = window.open("window_picker_no_crash_child.html", "childWindow", "width=500,height=500");
+  await SimpleTest.promiseFocus(childWindow);
+  ok(!childWindow.clicked, "Shouldn't have clicked");
+  synthesizeMouseAtCenter(childWindow.document.getElementById(id), {}, childWindow);
+  ok(childWindow.clicked, "Should have clicked");
+  childWindow.close();
+}
+
+add_task(async function test_simple() {
+  await testPicker("uploadbox");
+});
+
+add_task(async function test_multiple() {
+  await testPicker("multiple");
+});
+
+add_task(async function wait() {
+  await new Promise(r => setTimeout(r, 1000));
+  ok(true, "browser didn't crash");
+});
+</script>
diff --git a/widget/tests/test_platform_colors.xhtml b/widget/tests/test_platform_colors.xhtml
new file mode 100644
index 0000000000..8f9860d85b
--- /dev/null
+++ b/widget/tests/test_platform_colors.xhtml
@@ -0,0 +1,95 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Mac platform colors"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=518395">Mozilla Bug 518395</a>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+<box id="colorbox"></box>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+var colors = {
+  "activeborder": ["rgb(0, 0, 0)"],
+  "activecaption": ["rgb(204, 204, 204)"],
+  "appworkspace": ["rgb(255, 255, 255)"],
+  "background": ["rgb(99, 99, 206)"],
+  "buttonface": ["rgb(240, 240, 240)"],
+  "buttonhighlight": ["rgb(255, 255, 255)"],
+  "buttonshadow": ["rgb(220, 220, 220)"],
+  "buttontext": ["rgb(0, 0, 0)"],
+  "captiontext": ["rgb(0, 0, 0)"],
+  "graytext": ["rgb(127, 127, 127)"],
+  "highlight": ["rgb(115, 132, 153)", "rgb(127, 127, 127)", "rgb(56, 117, 215)", "rgb(255, 193, 31)", "rgb(243, 70, 72)", "rgb(255, 138, 34)", "rgb(102, 197, 71)", "rgb(140, 78, 184)"],
+  "highlighttext": ["rgb(255, 255, 255)", "rgb(255, 254, 254)", "rgb(254, 255, 254)"],
+  "inactiveborder": ["rgb(255, 255, 255)"],
+  "inactivecaption": ["rgb(255, 255, 255)"],
+  "inactivecaptiontext": ["rgb(69, 69, 69)"],
+  "infobackground": ["rgb(255, 255, 199)"],
+  "infotext": ["rgb(0, 0, 0)"],
+  "menu": ["rgb(255, 255, 255)", "rgb(254, 255, 254)", "rgb(255, 254, 254)"],
+  "menutext": ["rgb(0, 0, 0)"],
+  "scrollbar": ["rgb(170, 170, 170)"],
+  "threeddarkshadow": ["rgb(220, 220, 220)"],
+  "threedface": ["rgb(240, 240, 240)"],
+  "threedhighlight": ["rgb(255, 255, 255)"],
+  "threedlightshadow": ["rgb(218, 218, 218)"],
+  "threedshadow": ["rgb(224, 224, 224)"],
+  "window": ["rgb(255, 255, 255)"],
+  "windowframe": ["rgb(204, 204, 204)"],
+  "windowtext": ["rgb(0, 0, 0)"],
+  "-moz-activehyperlinktext": ["rgb(238, 0, 0)"],
+  "-moz-buttonhoverface": ["rgb(240, 240, 240)"],
+  "-moz-buttonhovertext": ["rgb(0, 0, 0)"],
+  "-moz-cellhighlight": ["rgb(212, 212, 212)", "rgb(220, 220, 220)"],
+  "-moz-cellhighlighttext": ["rgb(0, 0, 0)"],
+  "-moz-eventreerow": ["rgb(255, 255, 255)"],
+  "-moz-field": ["rgb(255, 255, 255)"],
+  "-moz-fieldtext": ["rgb(0, 0, 0)"],
+  "-moz-dialog": ["rgb(232, 232, 232)"],
+  "-moz-dialogtext": ["rgb(0, 0, 0)"],
+  "-moz-hyperlinktext": ["rgb(0, 0, 238)"],
+  "-moz-html-cellhighlight": ["rgb(212, 212, 212)"],
+  "-moz-html-cellhighlighttext": ["rgb(0, 0, 0)"],
+  "-moz-buttonactivetext": ["rgb(0, 0, 0)", "rgb(255, 255, 255)"],
+  "-moz-mac-defaultbuttontext": ["rgb(0, 0, 0)", "rgb(255, 255, 255)"],
+  //"-moz-mac-focusring": ["rgb(83, 144, 210)", "rgb(95, 112, 130)", "rgb(63, 152, 221)", "rgb(108, 126, 141)"],
+  "-moz-mac-menutextdisable": ["rgb(152, 152, 152)"],
+  "-moz-mac-menutextselect": ["rgb(255, 255, 255)"],
+  "-moz-mac-disabledtoolbartext": ["rgb(127, 127, 127)"],
+  "-moz-menuhover": ["rgb(115, 132, 153)", "rgb(127, 127, 127)", "rgb(56, 117, 215)", "rgb(255, 193, 31)", "rgb(243, 70, 72)", "rgb(255, 138, 34)", "rgb(102, 197, 71)", "rgb(140, 78, 184)"],
+  "-moz-menuhovertext": ["rgb(255, 255, 255)", "rgb(255, 254, 254)", "rgb(254, 255, 254)"],
+  //"-moz-menubarhovertext": ["rgb(255, 255, 255)"],
+  "-moz-oddtreerow": ["rgb(236, 242, 254)", "rgb(240, 240, 240)", "rgb(243, 245, 250)", "rgb(243, 246, 250)", "rgb(245, 245, 245)"],
+  "-moz-visitedhyperlinktext": ["rgb(85, 26, 139)"],
+  "currentcolor": ["rgb(0, 0, 0)"],
+  "-moz-comboboxtext": ["rgb(0, 0, 0)"],
+  "-moz-combobox": ["rgb(255, 255, 255)"]
+};
+
+var colorbox = document.getElementById('colorbox');
+
+for (var c in colors) {
+  dump("testing color " + c + "\n");
+  colorbox.style.backgroundColor = c;
+  var rgb = document.defaultView.getComputedStyle(colorbox).getPropertyValue('background-color');
+  ok(colors[c].includes(rgb) || colors[c].length == 8, 'platform color ' + c + ' is wrong: ' + rgb);
+}
+
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_position_on_resize.xhtml b/widget/tests/test_position_on_resize.xhtml
new file mode 100644
index 0000000000..a7c5551018
--- /dev/null
+++ b/widget/tests/test_position_on_resize.xhtml
@@ -0,0 +1,90 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+
+<window title="Window Position On Resize Test"
+        onload="startTest()"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"/>
+
+<script class="testbody" type="application/javascript"><![CDATA[
+  SimpleTest.waitForExplicitFinish();
+  let win, x, y;
+
+  function startTest() {
+    win = window.browsingContext.topChromeWindow.openDialog(
+        "about:blank",
+        null,
+        "chrome,dialog=no,outerHeight=170,outerWidth=200");
+    waitForSuccess(function() { return SpecialPowers.DOMWindowUtils.paintCount },
+                   "No paint received", checkInitialSize);
+  }
+
+  function checkInitialSize() {
+    is(win.outerHeight,170, "initial outerHeight");
+    is(win.outerWidth, 200, "initial outerWidth");
+    x = win.screenX;
+    y = win.screenY;
+    shrink();
+  }
+  function shrink() {
+    win.resizeTo(180, 160);
+    waitForSuccess(function() { return win.outerHeight == 160 },
+                   "outerHeight did not change to 160", checkShrink);
+  }
+  function checkShrink() {
+    is(win.outerWidth, 180, "resized outerWidth");
+    is(win.screenY, y, "resized window top should not change");
+    y = win.screenY;
+    restore();
+  }
+  function restore() {
+    win.resizeBy(20, 10);
+    waitForSuccess(function() { return win.outerHeight == 170 },
+                   "outerHeight did not change to 170", checkRestore);
+  }
+  function checkRestore() {
+    is(win.outerWidth, 200, "restored outerWidth");
+    is(win.screenX, x, "restored window left should not change");
+    is(win.screenY, y, "restored window top should not change");
+    done();
+  }
+  function done() {
+    win.close();
+    SimpleTest.finish();
+  }
+
+  function waitForSuccess(testForSuccess, failureMsg, nextFunc) {
+    var waitCount = 0;
+
+    function repeatWait() {
+      ++waitCount;
+
+      if (testForSuccess()) {
+        nextFunc();
+      }
+      else if (waitCount > 50) {
+        ok(false, failureMsg);
+        nextFunc();
+      } else {
+        setTimeout(repeatWait, 100);
+      }
+    }
+
+    repeatWait();
+  }
+]]></script>
+
+<body xmlns="http://www.w3.org/1999/xhtml">
+<p id="display">
+</p>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+</pre>
+</body>
+
+</window>
diff --git a/widget/tests/test_secure_input.html b/widget/tests/test_secure_input.html
new file mode 100644
index 0000000000..846465b4c2
--- /dev/null
+++ b/widget/tests/test_secure_input.html
@@ -0,0 +1,141 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <title>Test for secure input mode</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"></script>
+  <script src="chrome://mochikit/content/tests/SimpleTest/NativeKeyCodes.js"></script>
+  <link rel="stylesheet" type="text/css"
+          href="chrome://mochikit/content/tests/SimpleTest/test.css" />
+</head>
+<body>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+
+<p>
+  <input id="input_text" type="text"><br>
+  <input id="input_password" type="password"><br>
+  <input id="input_text_readonly" type="text" readonly><br>
+  <input id="input_text_ime_mode_disabled" type="text" style="ime-mode: disabled;"><br>
+  <input id="input_change" type="text"><br>
+  <textarea id="textarea"></textarea><br>
+</p>
+<div id="contenteditable" contenteditable style="min-height: 3em;"></div>
+
+<script class="testbody" type="application/javascript">
+
+  SimpleTest.waitForExplicitFinish();
+
+  function sendAKeyEvent() {
+    synthesizeNativeKey(KEYBOARD_LAYOUT_EN_US, MAC_VK_ANSI_A, {}, "a", "a");
+  }
+
+  function isFocused(aElement) {
+    return (SpecialPowers.focusManager.focusedElement == aElement);
+  }
+
+  function runTest() {
+    sendAKeyEvent();
+    ok(true, "Not crashed: input on the document");
+    $("input_text").focus();
+    sendAKeyEvent();
+    ok(true, "Not crashed: input on <input type=\"text\">");
+    $("input_password").focus();
+    sendAKeyEvent();
+    ok(true, "Not crashed: input on <input type=\"password\">");
+    $("input_password").blur();
+    sendAKeyEvent();
+    ok(true, "Not crashed: input on the document after blur() of <input type=\"password\">");
+    $("input_password").focus();
+    $("input_text_readonly").focus();
+    sendAKeyEvent();
+    ok(true, "Not crashed: input on <input type=\"text\" readonly>");
+    $("input_password").focus();
+    $("input_text_ime_mode_disabled").focus();
+    sendAKeyEvent();
+    ok(true, "Not crashed: input on <input type=\"text\" style=\"ime-mode: disabled;\">");
+    $("input_password").focus();
+    $("textarea").focus();
+    sendAKeyEvent();
+    ok(true, "Not crashed: input on <textarea>");
+    $("input_password").focus();
+    $("contenteditable").focus();
+    sendAKeyEvent();
+    ok(true, "Not crashed: input on <div contenteditable>");
+
+    $("input_change").focus();
+    $("input_change").type = "password";
+    sendAKeyEvent();
+    ok(true, "Not crashed: input on <input type=\"password\"> changed from type=\"text\"");
+    $("input_change").type = "text";
+    sendAKeyEvent();
+    ok(true, "Not crashed: input on <input type=\"text\"> changed from type=\"password\"");
+
+    var otherWindow =
+      window.browsingContext.topChromeWindow.open("file_secure_input.html",
+                                                  "_blank", "chrome,width=100,height=100");
+    ok(otherWindow, "failed to open other window");
+    if (!otherWindow) {
+      SimpleTest.finish();
+      return;
+    }
+
+    $("input_text").focus();
+    otherWindow.focus();
+
+    SimpleTest.waitForFocus(function() {
+      window.focus();
+      sendAKeyEvent();
+      ok(isFocused($("input_text")), "focused element isn't <input type=\"text\">");
+      ok(true, "Not crashed: input on <input type=\"text\"> after the other document has focus");
+
+      $("input_password").focus();
+      otherWindow.focus();
+      window.focus();
+      sendAKeyEvent();
+      ok(isFocused($("input_password")), "focused element isn't <input type=\"password\">");
+      ok(true, "Not crashed: input on <input type=\"password\"> after the other document has focus");
+
+      $("input_text").focus();
+      otherWindow.focus();
+      otherWindow.document.getElementById("text").focus();
+      window.focus();
+      sendAKeyEvent();
+      ok(isFocused($("input_text")), "focused element isn't <input type=\"text\">");
+      ok(true, "Not crashed: input on <input type=\"text\"> after the other document's <input type=\"text\"> has focus");
+
+      $("input_password").focus();
+      otherWindow.focus();
+      otherWindow.document.getElementById("text").focus();
+      window.focus();
+      sendAKeyEvent();
+      ok(isFocused($("input_password")), "focused element isn't <input type=\"password\">");
+      ok(true, "Not crashed: input on <input type=\"password\"> after the other document's <input type=\"text\"> has focus");
+
+      $("input_text").focus();
+      otherWindow.focus();
+      otherWindow.document.getElementById("password").focus();
+      window.focus();
+      sendAKeyEvent();
+      ok(isFocused($("input_text")), "focused element isn't <input type=\"text\">");
+      ok(true, "Not crashed: input on <input type=\"text\"> after the other document's <input type=\"password\"> has focus");
+
+      $("input_password").focus();
+      otherWindow.focus();
+      otherWindow.document.getElementById("password").focus();
+      window.focus();
+      sendAKeyEvent();
+      ok(isFocused($("input_password")), "focused element isn't <input type=\"password\">");
+      ok(true, "Not crashed: input on <input type=\"password\"> after the other document's <input type=\"password\"> has focus");
+
+      SimpleTest.finish();
+    }, otherWindow);
+  }
+
+  SimpleTest.waitForFocus(runTest);
+</script>
+</body>
+</html>
diff --git a/widget/tests/test_sizemode_events.xhtml b/widget/tests/test_sizemode_events.xhtml
new file mode 100644
index 0000000000..bd1e3a38d1
--- /dev/null
+++ b/widget/tests/test_sizemode_events.xhtml
@@ -0,0 +1,148 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Test for bug 715867"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<p id="display"></p>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody">
+<![CDATA[
+
+const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+
+let gWindow = null;
+
+const kIsLinux = navigator.platform.includes("Lin");
+const kIsMacOS = navigator.platform.includes("Mac");
+// On Linux and macOS sizemode changes might be async.
+const kAsyncChanges = kIsLinux || kIsMacOS;
+
+let gSizeModeDidChange = false;
+let gSizeModeDidChangeTo = 0;
+
+function sizemodeChanged(e) {
+  gSizeModeDidChange = true;
+  gSizeModeDidChangeTo = gWindow.windowState;
+}
+
+async function expectSizeModeChange(newMode, duringActionCallback) {
+  gSizeModeDidChange = false;
+
+  let promise = null;
+  if (kAsyncChanges) {
+    if (newMode) {
+      promise = new Promise(resolve => {
+        gWindow.addEventListener("sizemodechange", function() {
+          SimpleTest.executeSoon(resolve);
+        }, { once: true })
+      });
+    } else {
+      promise = new Promise(SimpleTest.executeSoon);
+    }
+  }
+
+  duringActionCallback();
+
+  if (promise) {
+    await promise;
+  }
+
+  if (newMode == 0) {
+    // No change should have taken place, no event should have fired.
+    ok(!gSizeModeDidChange, "No sizemodechange event should have fired.");
+  } else {
+    // Size mode change event was expected to fire.
+    ok(gSizeModeDidChange, "A sizemodechanged event should have fired.");
+    is(gSizeModeDidChangeTo, newMode, "The new sizemode should have the expected value.");
+    const expectedHidden = newMode == gWindow.STATE_MINIMIZED || gWindow.isFullyOccluded;
+    if (gWindow.document.hidden != expectedHidden) {
+      await new Promise(resolve => {
+        gWindow.addEventListener("visibilitychange", resolve, { once: true });
+      });
+    }
+    is(gWindow.document.hidden, expectedHidden, "Should be inactive if minimized or occluded.");
+  }
+}
+
+function startTest() {
+  openWindow();
+}
+
+function openWindow() {
+  gWindow = window.browsingContext.topChromeWindow
+                  .open('empty_window.xhtml', '_blank', 'chrome,screenX=50,screenY=50,width=200,height=200,resizable');
+  SimpleTest.waitForFocus(runTest, gWindow);
+}
+
+async function runTest() {
+  // Install event handler.
+  gWindow.addEventListener("sizemodechange", sizemodeChanged);
+
+  // Run tests.
+  info("Testing minimize()");
+  await expectSizeModeChange(gWindow.STATE_MINIMIZED, function () {
+    gWindow.minimize();
+  });
+
+  info("Testing restore() after minimize()");
+  await expectSizeModeChange(gWindow.STATE_NORMAL, function () {
+    gWindow.restore();
+  });
+
+  info("Testing maximize()");
+  await expectSizeModeChange(gWindow.STATE_MAXIMIZED, function () {
+    gWindow.maximize();
+  });
+
+  info("Testing restore() after maximize()");
+  await expectSizeModeChange(gWindow.STATE_NORMAL, function () {
+    gWindow.restore();
+  });
+
+  // Normal window resizing shouldn't fire a sizemodechanged event, bug 715867.
+  info("Testing resizeTo() horizontal");
+  await expectSizeModeChange(0, function () {
+    gWindow.resizeTo(gWindow.outerWidth + 10, gWindow.outerHeight);
+  });
+
+  info("Testing resizeTo() vertical");
+  await expectSizeModeChange(0, function () {
+    gWindow.resizeTo(gWindow.outerWidth, gWindow.outerHeight + 10);
+  });
+
+  // Resizing a maximized window should change to normal sizemode.
+  info("maximize() in preparation for resize");
+  await expectSizeModeChange(gWindow.STATE_MAXIMIZED, function () {
+    gWindow.maximize();
+  });
+
+  info("Testing resizeTo() from maximized");
+  await expectSizeModeChange(gWindow.STATE_NORMAL, function () {
+    // MacOS treats windows close to the available screen size as maximized.
+    // Shrinking the window by only 10px isn't enough to change the sizemode.
+    gWindow.resizeTo(gWindow.outerWidth / 2, gWindow.outerHeight / 2);
+  });
+
+  gWindow.removeEventListener("sizemodechange", sizemodeChanged);
+  gWindow.close();
+  SimpleTest.finish();
+}
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.waitForFocus(startTest);
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_standalone_native_menu.xhtml b/widget/tests/test_standalone_native_menu.xhtml
new file mode 100644
index 0000000000..96e41036c3
--- /dev/null
+++ b/widget/tests/test_standalone_native_menu.xhtml
@@ -0,0 +1,29 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Standalone Native Menu tests"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+window.openDialog("standalone_native_menu_window.xhtml", "StandaloneNativeMenuWindow", 
+                  "chrome,width=600,height=600,noopener", window);
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_surrogate_pair_native_key_handling.xhtml b/widget/tests/test_surrogate_pair_native_key_handling.xhtml
new file mode 100644
index 0000000000..98834e1206
--- /dev/null
+++ b/widget/tests/test_surrogate_pair_native_key_handling.xhtml
@@ -0,0 +1,178 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css" type="text/css"?>
+
+<window id="window1" title="Test handling of native key input for surrogate pairs"
+  xmlns:html="http://www.w3.org/1999/xhtml"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"/>
+  <script src="chrome://mochikit/content/tests/SimpleTest/NativeKeyCodes.js"/>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <p id="display"></p>
+    <div id="content" style="display: none"></div>
+    <pre id="test"></pre>
+  </body>
+
+  <script type="application/javascript"><![CDATA[
+    SimpleTest.waitForExplicitFinish();
+    SimpleTest.waitForFocus(async () => {
+      function promiseSynthesizeNativeKey(
+        aNativeKeyCode,
+        aChars,
+      ) {
+        return new Promise(resolve => {
+          synthesizeNativeKey(
+            KEYBOARD_LAYOUT_EN_US,
+            aNativeKeyCode,
+            {},
+            aChars,
+            aChars,
+            resolve
+          );
+        });
+      }
+      function getEventData(aEvent) {
+        return `{ type: "${aEvent.type}", key: "${aEvent.key}", code: "${
+          aEvent.code
+        }", keyCode: 0x${
+          aEvent.keyCode.toString(16).toUpperCase()
+        }, charCode: 0x${aEvent.charCode.toString(16).toUpperCase()} }`;
+      }
+      function getEventArrayData(aEvents) {
+        if (!aEvents.length) {
+          return "[]";
+        }
+        let result = "[\n";
+        for (const e of aEvents) {
+          result += `  ${getEventData(e)}\n`;
+        }
+        return result + "]";
+      }
+      let events = [];
+      function onKey(aEvent) {
+        events.push(aEvent);
+      }
+      window.addEventListener("keydown", onKey);
+      window.addEventListener("keypress", onKey);
+      window.addEventListener("keyup", onKey);
+
+      async function runTests(
+        aTestPerSurrogateKeyPress,
+        aTestIllFormedUTF16KeyValue = false
+      ) {
+        await SpecialPowers.pushPrefEnv({
+          set: [
+            ["dom.event.keypress.dispatch_once_per_surrogate_pair", !aTestPerSurrogateKeyPress],
+            ["dom.event.keypress.key.allow_lone_surrogate", aTestIllFormedUTF16KeyValue],
+          ],
+        });
+        const settingDescription =
+          `aTestPerSurrogateKeyPress=${
+            aTestPerSurrogateKeyPress
+          }, aTestIllFormedUTF16KeyValue=${aTestIllFormedUTF16KeyValue}`;
+        const allowIllFormedUTF16 =
+          aTestPerSurrogateKeyPress && aTestIllFormedUTF16KeyValue;
+
+        // If the keyboard layout has a key to introduce a surrogate pair,
+        // one set of WM_KEYDOWN and WM_KEYUP are generated and it's translated
+        // to two WM_CHARs.
+        await (async function test_one_key_press() {
+          events = [];
+          await promiseSynthesizeNativeKey(WIN_VK_A, "\uD83E\uDD14");
+          const keyCodeA = "A".charCodeAt(0);
+          is(
+            getEventArrayData(events),
+            getEventArrayData(
+              // eslint-disable-next-line no-nested-ternary
+              aTestPerSurrogateKeyPress
+                ? (
+                  allowIllFormedUTF16
+                    ? [
+                        { type: "keydown",  key: "\uD83E\uDD14", code: "KeyA", keyCode: keyCodeA, charCode: 0 },
+                        { type: "keypress", key: "\uD83E",       code: "KeyA", keyCode: 0,        charCode: 0xD83E },
+                        { type: "keypress", key: "\uDD14",       code: "KeyA", keyCode: 0,        charCode: 0xDD14 },
+                        { type: "keyup",    key: "a",            code: "KeyA", keyCode: keyCodeA, charCode: 0 }, // Cannot set .key properly without a hack
+                      ]
+                    : [
+                        { type: "keydown",  key: "\uD83E\uDD14", code: "KeyA", keyCode: keyCodeA, charCode: 0 },
+                        { type: "keypress", key: "\uD83E\uDD14", code: "KeyA", keyCode: 0,        charCode: 0xD83E },
+                        { type: "keypress", key: "",             code: "KeyA", keyCode: 0,        charCode: 0xDD14 },
+                        { type: "keyup",    key: "a",            code: "KeyA", keyCode: keyCodeA, charCode: 0 }, // Cannot set .key properly without a hack
+                      ]
+                  )
+                : [
+                    { type: "keydown",  key: "\uD83E\uDD14", code: "KeyA", keyCode: keyCodeA, charCode: 0 },
+                    { type: "keypress", key: "\uD83E\uDD14", code: "KeyA", keyCode: 0,        charCode: 0x1F914 },
+                    { type: "keyup",    key: "a",            code: "KeyA", keyCode: keyCodeA, charCode: 0 }, // Cannot set .key properly without a hack
+                  ]
+            ),
+            `test_one_key_press(${
+              settingDescription
+            }): Typing surrogate pair should cause one set of keydown and keyup events with ${
+              aTestPerSurrogateKeyPress ? "2 keypress events" : "a keypress event"
+            }`
+          );
+        })();
+
+        // If a surrogate pair is sent with SendInput API, 2 sets of keyboard
+        // events are generated.  E.g., Emojis in the touch keyboard on Win10 or
+        // later.
+        await (async function test_send_input() {
+          events = [];
+          // Virtual keycode for the WM_KEYDOWN/WM_KEYUP is VK_PACKET.
+          await promiseSynthesizeNativeKey(WIN_VK_PACKET, "\uD83E");
+          await promiseSynthesizeNativeKey(WIN_VK_PACKET, "\uDD14");
+          // WM_KEYDOWN, WM_CHAR and WM_KEYUP for the high surrogate input
+          // shouldn't cause DOM events.
+          is(
+            getEventArrayData(events),
+            getEventArrayData(
+              // eslint-disable-next-line no-nested-ternary
+              aTestPerSurrogateKeyPress
+                ? (
+                  allowIllFormedUTF16
+                    ? [
+                        { type: "keydown",  key: "\uD83E\uDD14", code: "", keyCode: 0, charCode: 0 },
+                        { type: "keypress", key: "\uD83E",       code: "", keyCode: 0, charCode: 0xD83E },
+                        { type: "keypress", key: "\uDD14",       code: "", keyCode: 0, charCode: 0xDD14 },
+                        { type: "keyup",    key: "",             code: "", keyCode: 0, charCode: 0 }, // Cannot set .key properly without a hack
+                      ]
+                    : [
+                        { type: "keydown",  key: "\uD83E\uDD14", code: "", keyCode: 0, charCode: 0 },
+                        { type: "keypress", key: "\uD83E\uDD14", code: "", keyCode: 0, charCode: 0xD83E },
+                        { type: "keypress", key: "",             code: "", keyCode: 0, charCode: 0xDD14 },
+                        { type: "keyup",    key: "",             code: "", keyCode: 0, charCode: 0 }, // Cannot set .key properly without a hack
+                      ]
+                  )
+                : [
+                    { type: "keydown",  key: "\uD83E\uDD14", code: "", keyCode: 0, charCode: 0 },
+                    { type: "keypress", key: "\uD83E\uDD14", code: "", keyCode: 0, charCode: 0x1F914 },
+                    { type: "keyup",    key: "",             code: "", keyCode: 0, charCode: 0 }, // Cannot set .key properly without a hack
+                  ]
+            ),
+            `test_send_input(${
+              settingDescription
+            }): Inputting surrogate pair should cause one set of keydown and keyup events ${
+              aTestPerSurrogateKeyPress ? "2 keypress events" : "a keypress event"
+            }`
+          );
+        })();
+      }
+
+      await runTests(true, true);
+      await runTests(true, false);
+      await runTests(false);
+
+      window.removeEventListener("keydown", onKey);
+      window.removeEventListener("keypress", onKey);
+      window.removeEventListener("keyup", onKey);
+
+      SimpleTest.finish();
+    });
+  ]]></script>
+
+</window>
diff --git a/widget/tests/test_system_font_changes.xhtml b/widget/tests/test_system_font_changes.xhtml
new file mode 100644
index 0000000000..036c775463
--- /dev/null
+++ b/widget/tests/test_system_font_changes.xhtml
@@ -0,0 +1,28 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Native menu system tests"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<p id="display"></p>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+window.openDialog("system_font_changes.xhtml", "system_font_changes_window",
+                  "chrome,width=600,height=600,noopener", window);
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/test_system_status_bar.xhtml b/widget/tests/test_system_status_bar.xhtml
new file mode 100644
index 0000000000..f2348fa6f5
--- /dev/null
+++ b/widget/tests/test_system_status_bar.xhtml
@@ -0,0 +1,53 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Testing composition, text and query content events"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<menupopup id="menuContainer">
+  <menu id="menu1" image="data:image/svg+xml,&lt;svg%20xmlns=&quot;http://www.w3.org/2000/svg&quot;%20width=&quot;32&quot;%20height=&quot;32&quot;>&lt;circle%20cx=&quot;16&quot;%20cy=&quot;16&quot;%20r=&quot;16&quot;/>&lt;/svg>">
+    <menupopup>
+      <menuitem label="Item 1 in menu 1"/>
+      <menuitem label="Item 2 in menu 1"/>
+    </menupopup>
+  </menu>
+  <menu id="menu2" image="data:image/svg+xml,&lt;svg%20xmlns=&quot;http://www.w3.org/2000/svg&quot;%20width=&quot;32&quot;%20height=&quot;32&quot;>&lt;path%20d=&quot;M0 16 L 16 0 L 32 16 L 16 32 Z&quot;/>&lt;/svg>">
+    <menupopup>
+      <menuitem label="Item 1 in menu 2"/>
+      <menuitem label="Item 2 in menu 2"/>
+    </menupopup>
+  </menu>
+</menupopup>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+  let systemStatusBar = Cc["@mozilla.org/widget/systemstatusbar;1"].getService(Ci.nsISystemStatusBar);
+  ok(systemStatusBar, "should have got an nsISystemStatusBar instance");
+
+  let menu1 = document.getElementById("menu1");
+  let menu2 = document.getElementById("menu2");
+
+  // Add and remove the item, just to get basic leak testing coverage.
+  systemStatusBar.addItem(menu1);
+  systemStatusBar.removeItem(menu1);
+
+  // Make sure that calling addItem twice with the same element doesn't leak.
+  systemStatusBar.addItem(menu2);
+  systemStatusBar.addItem(menu2);
+  systemStatusBar.removeItem(menu2);
+
+]]>
+</script>
+</window>
diff --git a/widget/tests/test_taskbar_progress.xhtml b/widget/tests/test_taskbar_progress.xhtml
new file mode 100644
index 0000000000..f2494a27bb
--- /dev/null
+++ b/widget/tests/test_taskbar_progress.xhtml
@@ -0,0 +1,117 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Taskbar Previews Test"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+  onload="loaded();">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+  <script class="testbody" type="application/javascript">
+  <![CDATA[
+    let TP = Ci.nsITaskbarProgress;
+    
+    function IsWin7OrHigher() {
+      try {
+        var ver = parseFloat(Services.sysinfo.getProperty("version"));
+        if (ver >= 6.1)
+          return true;
+      } catch (ex) { }
+      return false;
+    }
+
+    function winProgress() {
+      let taskbar = Cc["@mozilla.org/windows-taskbar;1"];
+      if (!taskbar) {
+        ok(false, "Taskbar service is always available");
+        return null;
+      }
+      taskbar = taskbar.getService(Ci.nsIWinTaskbar);
+
+      is(taskbar.available, IsWin7OrHigher(), "Expected availability of taskbar");
+      if (!taskbar.available)
+        return null;
+      
+      // HACK from mconnor:
+      let win = Services.wm.getMostRecentWindow("navigator:browser");
+      let docShell = win.docShell;
+
+      let progress = taskbar.getTaskbarProgress(docShell);
+      isnot(progress, null, "Progress is not null");
+
+      try {
+        taskbar.getTaskbarProgress(null);
+        ok(false, "Got progress for null docshell");
+      } catch (e) {
+        ok(true, "Cannot get progress for null docshell");
+      }
+      
+      return progress;
+    }
+    
+    function macProgress() {
+      let progress = Cc["@mozilla.org/widget/macdocksupport;1"];
+      if (!progress) {
+        ok(false, "Should have gotten Mac progress service.");
+        return null;
+      }
+      return progress.getService(TP);
+    }
+
+    SimpleTest.waitForExplicitFinish();
+
+    function loaded()
+    {
+      let isWin = /Win/.test(navigator.platform);
+      let progress = isWin ? winProgress() : macProgress();
+      if (!TP || !progress) {
+        SimpleTest.finish();
+        return;
+      }
+      
+      function shouldThrow(s,c,m) {
+        try {
+          progress.setProgressState(s,c,m);
+          return false;
+        } catch (e) {
+          return true;
+        }
+      }
+
+      function doesntThrow(s,c,m) {
+        return !shouldThrow(s,c,m);
+      }
+
+      ok(doesntThrow(TP.STATE_NO_PROGRESS, 0, 0), "No progress state can be set");
+      ok(doesntThrow(TP.STATE_INDETERMINATE, 0, 0), "Indeterminate state can be set");
+      ok(doesntThrow(TP.STATE_NORMAL, 0, 0), "Normal state can be set");
+      ok(doesntThrow(TP.STATE_ERROR, 0, 0), "Error state can be set");
+      ok(doesntThrow(TP.STATE_PAUSED, 0, 0), "Paused state can be set");
+
+      ok(shouldThrow(TP.STATE_NO_PROGRESS, 1, 1), "Cannot set no progress with values");
+      ok(shouldThrow(TP.STATE_INDETERMINATE, 1, 1), "Cannot set indeterminate with values");
+
+      // Technically passes since unsigned(-1) > 10
+      ok(shouldThrow(TP.STATE_NORMAL, -1, 10), "Cannot set negative progress");
+      todo(shouldThrow(TP.STATE_NORMAL, 1, -1), "Cannot set negative progress");
+      todo(shouldThrow(TP.STATE_NORMAL, -1, -1), "Cannot set negative progress");
+      todo(shouldThrow(TP.STATE_NORMAL, -2, -1), "Cannot set negative progress");
+
+      ok(shouldThrow(TP.STATE_NORMAL, 5, 3), "Cannot set progress greater than max");
+
+      ok(doesntThrow(TP.STATE_NORMAL, 1, 5), "Normal state can be set with values");
+      ok(doesntThrow(TP.STATE_ERROR, 3, 6), "Error state can be set with values");
+      ok(doesntThrow(TP.STATE_PAUSED, 2, 9), "Paused state can be set with values");
+
+      SimpleTest.finish();
+    }
+  ]]>
+  </script>
+
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <p id="display"></p>
+    <div id="content" style="display: none"></div>
+    <pre id="test"></pre>
+  </body>
+
+</window>
diff --git a/widget/tests/test_textScaleFactor_system_font.html b/widget/tests/test_textScaleFactor_system_font.html
new file mode 100644
index 0000000000..2d0333e5fa
--- /dev/null
+++ b/widget/tests/test_textScaleFactor_system_font.html
@@ -0,0 +1,139 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Test that system font sizing is independent from ui.textScaleFactor</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" href="/tests/SimpleTest/test.css"/>
+  <style>
+    p { width: max-content }
+    #menu { font: menu }
+  </style>
+</head>
+<body>
+  <p id="menu">"menu" text.</p>
+  <p id="default">Default text.</p>
+</body>
+<script>
+"use strict";
+
+const { AppConstants } = SpecialPowers.ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+
+// Returns a Number for the font size in CSS pixels.
+function elementFontSize(element) {
+  return parseFloat(getComputedStyle(element).getPropertyValue("font-size"));
+}
+
+// "look-and-feel-changed" may be dispatched twice: once for the pref
+// change and once after receiving the new values from
+// ContentChild::RecvThemeChanged().
+// pushPrefEnv() resolves after the former. This resolves after the latter.
+function promiseNewFontSizeOnThemeChange(element) {
+  return new Promise(resolve => {
+    const lastSize = elementFontSize(element);
+
+    function ThemeChanged() {
+      const size = elementFontSize(element);
+      if (size != lastSize) {
+        resolve(size);
+      }
+    }
+    // "look-and-feel-changed" is dispatched before the style system is flushed,
+    // https://searchfox.org/mozilla-central/rev/380fc5571b039fd453b45bbb64ed13146fe9b066/layout/base/nsPresContext.cpp#1684,1703-1705
+    // so use an async observer to get a notification after style changes.
+    SpecialPowers.addAsyncObserver(ThemeChanged, "look-and-feel-changed");
+    SimpleTest.registerCleanupFunction(function() {
+      SpecialPowers.removeAsyncObserver(ThemeChanged, "look-and-feel-changed");
+    });
+  });
+}
+
+function fuzzyCompareLength(actual, expected, message, tolerance, expectFn) {
+  expectFn(Math.abs(actual-expected) <= tolerance,
+           `${message} - got ${actual}, expected ${expected} +/- ${tolerance}`);
+}
+
+add_task(async () => {
+  // MOZ_HEADLESS is set in content processes with GTK regardless of the
+  // headless state of the parent process.  Check the parent state.
+  const headless = await SpecialPowers.spawnChrome([], function get_headless() {
+    return Services.env.get("MOZ_HEADLESS");
+  });
+  // LookAndFeel::TextScaleFactor::FloatID is implemented only for WINNT and
+  // GTK.  ui.textScaleFactor happens to scale CSS pixels on other platforms
+  // but system font integration has not been implemented.
+  const expectSuccess = AppConstants.MOZ_WIDGET_TOOLKIT == "windows" ||
+         (AppConstants.MOZ_WIDGET_TOOLKIT == "gtk" &&
+          // Headless GTK doesn't get system font sizes from the system, but
+          // uses sizes fixed in CSS pixels.
+          !headless);
+
+  async function setScaleAndPromiseFontSize(scale, element) {
+    const prefPromise = SpecialPowers.pushPrefEnv({
+      set: [["ui.textScaleFactor", scale]],
+    });
+    if (!expectSuccess) {
+      // The size is not expected to change but get it afresh to check our
+      // assumption.
+      await prefPromise;
+      return elementFontSize(element);
+    }
+    const [size] = await Promise.all([
+      promiseNewFontSizeOnThemeChange(element),
+      prefPromise,
+    ]);
+    return size;
+  }
+
+  const menu = document.getElementById("menu");
+  const def = document.getElementById("default");
+  // Choose a scaleFactor value different enough from possible default values
+  // that app unit rounding does not prevent a change in devicePixelRatio.
+  // A scaleFactor of 120 also has no rounding of app units per dev pixel.
+  const referenceScale = 120;
+  const menuSize1 = await setScaleAndPromiseFontSize(referenceScale, menu);
+  const menuRect1 = menu.getBoundingClientRect();
+  const defSize1 = elementFontSize(def);
+  const defRect1 = def.getBoundingClientRect();
+
+  const expectFn = expectSuccess ? ok : todo;
+  const menuSize2 = await setScaleAndPromiseFontSize(2*referenceScale, menu);
+  {
+    const singlePrecisionULP = Math.pow(2, -23);
+    // Precision seems to be lost in the conversion to decimal string for the
+    // property value.
+    const reltolerance = 30 * singlePrecisionULP;
+    fuzzyCompareLength(menuSize2, menuSize1/2, "size of menu font",
+                       reltolerance*menuSize1/2, expectFn);
+  }
+  {
+    const menuRect2 = menu.getBoundingClientRect();
+    // The menu font text renders exactly the same and app-unit rects are
+    // equal, but the DOMRect conversion is rounded to 1/65536 CSS pixels.
+    // https://searchfox.org/mozilla-central/rev/380fc5571b039fd453b45bbb64ed13146fe9b066/dom/base/DOMRect.cpp#151-159
+    // See also https://bugzilla.mozilla.org/show_bug.cgi?id=1640441#c28
+    const absTolerance = 1/65536
+    fuzzyCompareLength(menuRect2.width, menuRect1.width/2,
+                       "width of menu font <p> in px", absTolerance, expectFn);
+    fuzzyCompareLength(menuRect2.height, menuRect1.height/2,
+                       "height of menu font <p> in px", absTolerance, expectFn);
+  }
+
+  const defSize2 = elementFontSize(def);
+  is(defSize2, defSize1, "size of default font");
+  {
+    const defRect2 = def.getBoundingClientRect();
+    // Wider tolerance for hinting and snapping
+    const relTolerance = 1/12;
+    fuzzyCompareLength(defRect2.width, defRect1.width,
+                       "width of default font <p> in px",
+                       relTolerance*defRect1.width, ok);
+    fuzzyCompareLength(defRect2.height, defRect1.height,
+                       "height of default font <p> in px",
+                       relTolerance*defRect1.height, ok);
+  }
+});
+</script>
+</html>
diff --git a/widget/tests/test_transferable_overflow.xhtml b/widget/tests/test_transferable_overflow.xhtml
new file mode 100644
index 0000000000..dca9edcc61
--- /dev/null
+++ b/widget/tests/test_transferable_overflow.xhtml
@@ -0,0 +1,155 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
+<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
+<window title="nsTransferable with large string"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        onload="RunTest();">
+  <title>nsTransferable with large string</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
+
+  <script type="application/javascript">
+  <![CDATA[
+  // This value is chosen such that the size of the memory for the string exceeds
+  // the kLargeDatasetSize threshold in nsTransferable.h (one million).
+  // Each character of a JS string is internally represented by two bytes,
+  // so the following string of length 500 001 uses 1 000 002 bytes.
+  const BIG_STRING = "x" + "BIGGY".repeat(100000);
+
+  // Some value with a length that is exactly kLargeDatasetSize (1 000 000).
+  const SMALL_STRING = "small".repeat(100000);
+
+  const nsTransferable = Components.Constructor("@mozilla.org/widget/transferable;1", "nsITransferable");
+  const nsSupportsString = Components.Constructor("@mozilla.org/supports-string;1", "nsISupportsString");
+
+  function assignTextToTransferable(transferable, string) {
+    var Suppstr = nsSupportsString();
+    Suppstr.data = string;
+    transferable.setTransferData("text/plain", Suppstr);
+  }
+
+  function checkTransferableText(transferable, expectedString, description) {
+    var data = {};
+    transferable.getTransferData("text/plain", data);
+    var actualValue = data.value.QueryInterface(Ci.nsISupportsString).data;
+    // Use ok + shortenString instead of is(...) to avoid dumping millions of characters in the output.
+    ok(actualValue === expectedString, description + ": text should match. " +
+       "Expected " + shortenString(expectedString)  + ", got " + shortenString(actualValue));
+
+    function shortenString(str) {
+      return str && str.length > 30 ? str.slice(0, 10) + "..." + str.slice(-10) : String(str);
+    }
+  }
+
+  function isFDCountingSupported() {
+    // On on-Windows we can count the number of file handles for the current process,
+    // while on Windows we need to count the number of files in ${TempD}\mozilla-temp-files\,
+    // which can be unreliable, especially because nsAnonymousTemporaryFile has documented
+    // that the deletion might not be immediate.
+    //
+    // To avoid intermittents, we only check the file descriptor counts on non-Windows.
+    // test_bug1123480.xhtml will do some basic testing for Windows.
+    const {AppConstants} = ChromeUtils.importESModule(
+      "resource://gre/modules/AppConstants.sys.mjs"
+    );
+    return AppConstants.platform !== 'win';
+  }
+
+  function getClipboardCacheFDCount() {
+    var dir = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
+    dir.initWithPath("/dev/fd");
+    var count = 0;
+    for (var de = dir.directoryEntries; de.hasMoreElements(); ) {
+      var fdFile = de.nextFile;
+      var fileSize;
+      try {
+        fileSize = fdFile.fileSize;
+      } catch (e) {
+        // This can happen on macOS.
+        continue;
+      }
+      if (fileSize === BIG_STRING.length * 2 ||
+          // We are not expecting files of this small size,
+          // but include them in the count anyway
+          // in case the files are unexpectedly created.
+          fileSize === SMALL_STRING.length * 2) {
+        // Assume that the file was created by us if the size matches.
+        ++count;
+      }
+    }
+    return count;
+  }
+
+  function RunTest() {
+    const {PrivateBrowsingUtils} = ChromeUtils.importESModule(
+      "resource://gre/modules/PrivateBrowsingUtils.sys.mjs"
+    );
+
+    var win = window.browsingContext.topChromeWindow.open("about:blank", "_blank", "chrome, width=500, height=200");
+    ok(win, "should open window");
+    is(PrivateBrowsingUtils.isContentWindowPrivate(win), false, "used correct window context");
+
+    // ### Part 1 - Writing to the clipboard.
+
+    var Loadctx = PrivateBrowsingUtils.privacyContextFromWindow(win);
+    var Transfer = nsTransferable();
+    Transfer.init(Loadctx);
+    Transfer.addDataFlavor("text/plain");
+    var initialFdCount = isFDCountingSupported() ? getClipboardCacheFDCount() : -1;
+
+    assignTextToTransferable(Transfer, BIG_STRING);
+    checkTransferableText(Transfer, BIG_STRING, "transferable after assigning BIG_STRING");
+    if (isFDCountingSupported()) {
+      is(getClipboardCacheFDCount(), initialFdCount + 1, "should use a file for BIG_STRING");
+    }
+
+    // Share the transferable with the system.
+    Services.clipboard.setData(Transfer, null, Services.clipboard.kGlobalClipboard);
+
+    // Sanity check: Copying to the clipboard should not have altered the transferable.
+    checkTransferableText(Transfer, BIG_STRING, "transferable after copying to clipboard");
+    if (isFDCountingSupported()) {
+      // We are only counting file descriptors for the current process,
+      // so even if the test were to be multi-process and the parent process creates another
+      // nsTransferable, then the count should still be the same.
+      is(getClipboardCacheFDCount(), initialFdCount + 1, "should still be using files for previously stored BIG_STRING");
+
+      // Re-establish baseline for the second part of the test below.
+      initialFdCount = getClipboardCacheFDCount();
+    }
+
+    // ### Part 2 - Reading from the clipboard.
+
+    var Transfer2 = nsTransferable();
+    Transfer2.init(Loadctx);
+    Transfer2.addDataFlavor("text/plain");
+
+    // Iniitalize with a small string, so we can see that mData -> mCacheFD works.
+    assignTextToTransferable(Transfer2, SMALL_STRING);
+    checkTransferableText(Transfer2, SMALL_STRING, "transferable after assigning SMALL_STRING");
+    if (isFDCountingSupported()) {
+      is(getClipboardCacheFDCount(), initialFdCount, "should not use file to store SMALL_STRING.");
+    }
+
+    // Check whether the clipboard data can be read, and simulatenously trigger mData -> mCacheFD.
+    Services.clipboard.getData(Transfer2, Services.clipboard.kGlobalClipboard, SpecialPowers.wrap(window).browsingContext.currentWindowContext);
+    checkTransferableText(Transfer2, BIG_STRING, "transferable after retrieving from clipboard");
+    if (isFDCountingSupported()) {
+      is(getClipboardCacheFDCount(), initialFdCount + 1, "should use a file for BIG_STRING (read from clipboard).");
+    }
+
+    // Store a small string, to exercise the code path from mCacheFD -> mData.
+    assignTextToTransferable(Transfer2, SMALL_STRING);
+    checkTransferableText(Transfer2, SMALL_STRING, "transferable after assigning SMALL_STRING");
+    if (isFDCountingSupported()) {
+      is(getClipboardCacheFDCount(), initialFdCount, "should release the file after clearing the transferable.");
+    }
+  }
+  ]]>
+  </script>
+
+  <!-- test results are displayed in the html:body -->
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    This test checks whether a big string can be copied to the clipboard, and then retrieved in the same form.
+    On non-Windows, the test also checks whether the data of the transferable is really stored in a file.
+  </body>
+</window>
diff --git a/widget/tests/test_wheeltransaction.xhtml b/widget/tests/test_wheeltransaction.xhtml
new file mode 100644
index 0000000000..23e855c39b
--- /dev/null
+++ b/widget/tests/test_wheeltransaction.xhtml
@@ -0,0 +1,27 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Wheel scroll transaction tests"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+SimpleTest.waitForExplicitFinish();
+window.openDialog("window_wheeltransaction.xhtml", "_blank", 
+                  "chrome,width=600,height=600,noopener", window);
+
+]]>
+</script>
+</window>
diff --git a/widget/tests/unit/test_macsharingservice.js b/widget/tests/unit/test_macsharingservice.js
new file mode 100644
index 0000000000..f6b0a8e3fc
--- /dev/null
+++ b/widget/tests/unit/test_macsharingservice.js
@@ -0,0 +1,61 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Basic tests to verify that MacSharingService returns expected data
+
+function test_getSharingProviders() {
+  let sharingService = Cc["@mozilla.org/widget/macsharingservice;1"].getService(
+    Ci.nsIMacSharingService
+  );
+
+  // Ensure these URL's are accepted without error by the getSharingProviders()
+  // method. This does not test if the URL's are interpreted correctly by
+  // the platform implementation and does not test that the URL will be
+  // successfully shared to the target application if the shareURL method is
+  // used. It does indicate the Mac API's used to get the sharing providers
+  // successfully created a URL object for the URL provided and returned at
+  // least one provider.
+  let urls = [
+    "http://example.org",
+    "http://example.org/#",
+    "http://example.org/dkl??",
+    "http://example.org/dkl?a=b;c=d#thisisaref",
+    "http://example.org/dkl?a=b;c=d#thisisaref#double",
+    "http://example.org/#/",
+    "http://example.org/#/#",
+    "http://example.org/#/#/",
+    // This test fails due to the '|' in the path which needs additional
+    // encoding before conversion to NSURL. See bug 1740565.
+    // "http://example.org/foo/bar/x|page.html#this_is_a_fragment",
+    "http://example.org/page.html#this_is_a_fragment",
+    "http://example.org/page.html#this_is_a_fragment#and_another",
+    "http://example.org/foo/bar;#foo",
+    "http://example.org/a file with spaces.html",
+    "https://chat.mozilla.org/#/room/#macdev:mozilla.org",
+    "https://chat.mozilla.org/#/room/%23macdev:mozilla.org",
+  ];
+
+  urls.forEach(url => testGetSharingProvidersForUrl(sharingService, url));
+}
+
+function testGetSharingProvidersForUrl(sharingService, url) {
+  let providers = sharingService.getSharingProviders(url);
+  Assert.greater(providers.length, 1, "There are providers returned");
+  providers.forEach(provider => {
+    Assert.ok("name" in provider, "Provider has name");
+    Assert.ok("menuItemTitle" in provider, "Provider has menuItemTitle");
+    Assert.ok("image" in provider, "Provider has image");
+
+    Assert.notEqual(
+      provider.title,
+      "Mail",
+      "Known filtered provider not returned"
+    );
+  });
+}
+
+function run_test() {
+  test_getSharingProviders();
+}
diff --git a/widget/tests/unit/test_macwebapputils.js b/widget/tests/unit/test_macwebapputils.js
new file mode 100644
index 0000000000..8967f8a593
--- /dev/null
+++ b/widget/tests/unit/test_macwebapputils.js
@@ -0,0 +1,34 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Basic tests to verify that MacWebAppUtils works
+
+function test_find_app() {
+  var mwaUtils = Cc["@mozilla.org/widget/mac-web-app-utils;1"].createInstance(
+    Ci.nsIMacWebAppUtils
+  );
+  let sig = "com.apple.TextEdit";
+
+  let path;
+  path = mwaUtils.pathForAppWithIdentifier(sig);
+  info("TextEdit path: " + path + "\n");
+  Assert.notEqual(path, "");
+}
+
+function test_dont_find_fake_app() {
+  var mwaUtils = Cc["@mozilla.org/widget/mac-web-app-utils;1"].createInstance(
+    Ci.nsIMacWebAppUtils
+  );
+  let sig = "calliope.penitentiary.dramamine";
+
+  let path;
+  path = mwaUtils.pathForAppWithIdentifier(sig);
+  Assert.equal(path, "");
+}
+
+function run_test() {
+  test_find_app();
+  test_dont_find_fake_app();
+}
diff --git a/widget/tests/unit/test_taskbar_legacyjumplistitems.js b/widget/tests/unit/test_taskbar_legacyjumplistitems.js
new file mode 100644
index 0000000000..e0173fd29e
--- /dev/null
+++ b/widget/tests/unit/test_taskbar_legacyjumplistitems.js
@@ -0,0 +1,229 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This tests taskbar jump list functionality available on win7 and up.
+
+function test_basics() {
+  var item = Cc["@mozilla.org/windows-legacyjumplistitem;1"].createInstance(
+    Ci.nsILegacyJumpListItem
+  );
+
+  var sep = Cc["@mozilla.org/windows-legacyjumplistseparator;1"].createInstance(
+    Ci.nsILegacyJumpListSeparator
+  );
+
+  var shortcut = Cc[
+    "@mozilla.org/windows-legacyjumplistshortcut;1"
+  ].createInstance(Ci.nsILegacyJumpListShortcut);
+
+  var link = Cc["@mozilla.org/windows-legacyjumplistlink;1"].createInstance(
+    Ci.nsILegacyJumpListLink
+  );
+
+  Assert.ok(!item.equals(sep));
+  Assert.ok(!item.equals(shortcut));
+  Assert.ok(!item.equals(link));
+
+  Assert.ok(!sep.equals(item));
+  Assert.ok(!sep.equals(shortcut));
+  Assert.ok(!sep.equals(link));
+
+  Assert.ok(!shortcut.equals(item));
+  Assert.ok(!shortcut.equals(sep));
+  Assert.ok(!shortcut.equals(link));
+
+  Assert.ok(!link.equals(item));
+  Assert.ok(!link.equals(sep));
+  Assert.ok(!link.equals(shortcut));
+
+  Assert.ok(item.equals(item));
+  Assert.ok(sep.equals(sep));
+  Assert.ok(link.equals(link));
+  Assert.ok(shortcut.equals(shortcut));
+}
+
+function test_separator() {
+  // separators:
+
+  var item = Cc[
+    "@mozilla.org/windows-legacyjumplistseparator;1"
+  ].createInstance(Ci.nsILegacyJumpListSeparator);
+
+  Assert.ok(item.type == Ci.nsILegacyJumpListItem.JUMPLIST_ITEM_SEPARATOR);
+}
+
+function test_links() {
+  // links:
+  var link1 = Cc["@mozilla.org/windows-legacyjumplistlink;1"].createInstance(
+    Ci.nsILegacyJumpListLink
+  );
+  var link2 = Cc["@mozilla.org/windows-legacyjumplistlink;1"].createInstance(
+    Ci.nsILegacyJumpListLink
+  );
+
+  var uri1 = Cc["@mozilla.org/network/simple-uri-mutator;1"]
+    .createInstance(Ci.nsIURIMutator)
+    .setSpec("http://www.test.com/")
+    .finalize();
+  var uri2 = Cc["@mozilla.org/network/simple-uri-mutator;1"]
+    .createInstance(Ci.nsIURIMutator)
+    .setSpec("http://www.test.com/")
+    .finalize();
+
+  link1.uri = uri1;
+  link1.uriTitle = "Test";
+  link2.uri = uri2;
+  link2.uriTitle = "Test";
+
+  Assert.ok(link1.equals(link2));
+
+  link2.uriTitle = "Testing";
+
+  Assert.ok(!link1.equals(link2));
+
+  link2.uriTitle = "Test";
+  uri2 = uri2.mutate().setSpec("http://www.testing.com/").finalize();
+  link2.uri = uri2;
+
+  Assert.ok(!link1.equals(link2));
+}
+
+function test_shortcuts() {
+  // shortcuts:
+  var sc = Cc["@mozilla.org/windows-legacyjumplistshortcut;1"].createInstance(
+    Ci.nsILegacyJumpListShortcut
+  );
+
+  var handlerApp = Cc[
+    "@mozilla.org/uriloader/local-handler-app;1"
+  ].createInstance(Ci.nsILocalHandlerApp);
+
+  handlerApp.name = "TestApp";
+  handlerApp.detailedDescription = "TestApp detailed description.";
+  handlerApp.appendParameter("-test");
+
+  sc.iconIndex = 1;
+  Assert.equal(sc.iconIndex, 1);
+
+  var faviconPageUri = Cc["@mozilla.org/network/simple-uri-mutator;1"]
+    .createInstance(Ci.nsIURIMutator)
+    .setSpec("http://www.123.com/")
+    .finalize();
+  sc.faviconPageUri = faviconPageUri;
+  Assert.equal(sc.faviconPageUri, faviconPageUri);
+
+  var notepad = Services.dirsvc.get("WinD", Ci.nsIFile);
+  notepad.append("notepad.exe");
+  if (notepad.exists()) {
+    handlerApp.executable = notepad;
+    sc.app = handlerApp;
+    Assert.equal(sc.app.detailedDescription, "TestApp detailed description.");
+    Assert.equal(sc.app.name, "TestApp");
+    Assert.ok(sc.app.parameterExists("-test"));
+    Assert.ok(!sc.app.parameterExists("-notset"));
+  }
+}
+
+async function test_legacyjumplist() {
+  // Jump lists can't register links unless the application is the default
+  // protocol handler for the protocol of the link, so we skip off testing
+  // those in these tests. We'll init the jump list for the xpc shell harness,
+  // add a task item, and commit it.
+
+  // not compiled in
+  if (Ci.nsIWinTaskbar == null) {
+    return;
+  }
+
+  var taskbar = Cc["@mozilla.org/windows-taskbar;1"].getService(
+    Ci.nsIWinTaskbar
+  );
+
+  // Since we're only testing the general functionality of the JumpListBuilder
+  // et. al, we can just test the non-private browsing version.
+  // (The only difference between the two at this level is the App User Model ID.)
+  var builder = taskbar.createLegacyJumpListBuilder(false);
+
+  Assert.notEqual(builder, null);
+
+  // Win7 and up only
+  try {
+    var ver = parseFloat(Services.sysinfo.getProperty("version"));
+    if (ver < 6.1) {
+      Assert.ok(!builder.available);
+      return;
+    }
+  } catch (ex) {}
+
+  Assert.ok(taskbar.available);
+
+  builder.deleteActiveList();
+
+  var items = Cc["@mozilla.org/array;1"].createInstance(Ci.nsIMutableArray);
+
+  var sc = Cc["@mozilla.org/windows-legacyjumplistshortcut;1"].createInstance(
+    Ci.nsILegacyJumpListShortcut
+  );
+
+  var handlerApp = Cc[
+    "@mozilla.org/uriloader/local-handler-app;1"
+  ].createInstance(Ci.nsILocalHandlerApp);
+
+  handlerApp.name = "Notepad";
+  handlerApp.detailedDescription = "Testing detailed description.";
+
+  var notepad = Services.dirsvc.get("WinD", Ci.nsIFile);
+  notepad.append("notepad.exe");
+  if (notepad.exists()) {
+    // To ensure "profile-before-change" will fire before
+    // "xpcom-shutdown-threads"
+    do_get_profile();
+
+    handlerApp.executable = notepad;
+    sc.app = handlerApp;
+    items.appendElement(sc);
+
+    var removed = Cc["@mozilla.org/array;1"].createInstance(Ci.nsIMutableArray);
+    Assert.ok(builder.initListBuild(removed));
+    Assert.ok(builder.addListToBuild(builder.JUMPLIST_CATEGORY_TASKS, items));
+    Assert.ok(builder.addListToBuild(builder.JUMPLIST_CATEGORY_RECENT));
+    Assert.ok(builder.addListToBuild(builder.JUMPLIST_CATEGORY_FREQUENT));
+    let rv = new Promise(resolve => {
+      builder.commitListBuild(resolve);
+    });
+    Assert.ok(await rv);
+
+    builder.deleteActiveList();
+
+    Assert.ok(builder.initListBuild(removed));
+    Assert.ok(
+      builder.addListToBuild(
+        builder.JUMPLIST_CATEGORY_CUSTOMLIST,
+        items,
+        "Custom List"
+      )
+    );
+    rv = new Promise(resolve => {
+      builder.commitListBuild(resolve);
+    });
+    Assert.ok(await rv);
+
+    builder.deleteActiveList();
+  }
+}
+
+function run_test() {
+  if (mozinfo.os != "win") {
+    return;
+  }
+  test_basics();
+  test_separator();
+  test_links();
+  test_shortcuts();
+
+  run_next_test();
+}
+
+add_task(test_legacyjumplist);
diff --git a/widget/tests/unit/xpcshell.toml b/widget/tests/unit/xpcshell.toml
new file mode 100644
index 0000000000..4e702ca356
--- /dev/null
+++ b/widget/tests/unit/xpcshell.toml
@@ -0,0 +1,11 @@
+[DEFAULT]
+head = ""
+
+["test_macsharingservice.js"]
+run-if = ["os == 'mac'"]
+
+["test_macwebapputils.js"]
+run-if = ["os == 'mac'"]
+
+["test_taskbar_legacyjumplistitems.js"]
+skip-if = ["os == 'win'"]
diff --git a/widget/tests/window_bug429954.xhtml b/widget/tests/window_bug429954.xhtml
new file mode 100644
index 0000000000..ca26d52621
--- /dev/null
+++ b/widget/tests/window_bug429954.xhtml
@@ -0,0 +1,44 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="Mozilla Bug 478536"
+  onload="start();"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js" />
+
+<body xmlns="http://www.w3.org/1999/xhtml" id="body">
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+function ok(aCondition, aMessage)
+{
+  window.browsingContext.topChromeWindow.opener.wrappedJSObject.SimpleTest.ok(aCondition, aMessage);
+}
+
+function is(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.is(aLeft, aRight, aMessage);
+}
+
+function isnot(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.isnot(aLeft, aRight, aMessage);
+}
+
+function start() {
+  var oldWidth = window.outerWidth, oldHeight = window.outerHeight;
+  window.maximize();
+  window.restore();
+  is(window.outerWidth, oldWidth, "wrong window width after maximize+restore");
+  is(window.outerHeight, oldHeight, "wrong window height after maximize+restore");
+  window.arguments[0].SimpleTest.finish();
+  window.close();
+}
+
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/window_bug478536.xhtml b/widget/tests/window_bug478536.xhtml
new file mode 100644
index 0000000000..7318eb0bff
--- /dev/null
+++ b/widget/tests/window_bug478536.xhtml
@@ -0,0 +1,211 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="Mozilla Bug 478536"
+  width="600" height="600"
+  onload="onload();"
+  onunload="onunload();"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js" />
+  <script src="chrome://mochikit/content/tests/SimpleTest/paint_listener.js" />
+
+<body xmlns="http://www.w3.org/1999/xhtml" id="body">
+<style type="text/css">
+  #view {
+    overflow: auto;
+    width: 100px;
+    height: 100px;
+    border: 1px solid;
+    margin: 0;
+  }
+</style>
+<pre id="view" onscroll="onScrollView(event);">
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+function ok(aCondition, aMessage)
+{
+  window.arguments[0].SimpleTest.ok(aCondition, aMessage);
+}
+
+function is(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.is(aLeft, aRight, aMessage);
+}
+
+function isnot(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.isnot(aLeft, aRight, aMessage);
+}
+
+var gBody = document.getElementById("body");
+var gView = document.getElementById("view");
+
+/**
+ * Description:
+ *
+ *   First, lock the wheel scrolling target to "view" at first step.
+ *   Next, scroll back to top most of the "view" at second step.
+ *   Finally, scroll back again at third step.  This fails to scroll the "view",
+ *   then, |onMouseScrollFailed| event should be fired.  And at that time, we
+ *   can remove the "view".  So, in post processing of the event firere, the
+ *   "view" should not be referred.
+ *
+ *   For suppressing random test failure, all tests will be retried if we handle
+ *   unexpected timeout event.
+ */
+
+var gTests = [
+ { scrollToForward: true,  shouldScroll: true },
+ { scrollToForward: false, shouldScroll: true },
+ { scrollToForward: false, shouldScroll: false }
+];
+var gCurrentTestIndex = -1;
+var gIgnoreScrollEvent = true;
+
+var gPrefSvc = SpecialPowers.Services.prefs;
+const kPrefSmoothScroll = "general.smoothScroll";
+const kPrefNameTimeout = "mousewheel.transaction.timeout";
+const kDefaultTimeout = gPrefSvc.getIntPref(kPrefNameTimeout);
+
+gPrefSvc.setBoolPref(kPrefSmoothScroll, false);
+
+var gTimeout = kDefaultTimeout;
+
+gBody.addEventListener("MozMouseScrollFailed", onMouseScrollFailed);
+gBody.addEventListener("MozMouseScrollTransactionTimeout",
+                       onTransactionTimeout);
+
+function setTimeoutPrefs(aTimeout)
+{
+  gPrefSvc.setIntPref(kPrefNameTimeout, aTimeout);
+  gTimeout = aTimeout;
+}
+
+function resetTimeoutPrefs()
+{
+  if (gTimeout == kDefaultTimeout)
+    return;
+  setTimeoutPrefs(kDefaultTimeout);
+}
+
+function growUpTimeoutPrefs()
+{
+  if (gTimeout != kDefaultTimeout)
+    return;
+  setTimeoutPrefs(5000);
+}
+
+function onload()
+{
+  disableNonTestMouseEvents(true);
+  setTimeout(runNextTest, 0);
+}
+
+function onunload()
+{
+  resetTimeoutPrefs();
+  disableNonTestMouseEvents(false);
+  gPrefSvc.clearUserPref(kPrefSmoothScroll);
+  SpecialPowers.DOMWindowUtils.restoreNormalRefresh();
+  window.arguments[0].SimpleTest.finish();
+}
+
+function finish()
+{
+  window.close();
+}
+
+// testing code
+
+var gTimer;
+function clearTimer()
+{
+  clearTimeout(gTimer);
+  gTimer = 0;
+}
+
+function runNextTest()
+{
+  clearTimer();
+  if (++gCurrentTestIndex >= gTests.length) {
+    ok(true, "didn't crash, succeeded");
+    finish();
+    return;
+  }
+  fireWheelScrollEvent(gTests[gCurrentTestIndex].scrollToForward);
+}
+
+var gRetryCount = 5;
+function retryAllTests()
+{
+  clearTimer();
+  if (--gRetryCount >= 0) {
+    gView.scrollTop = 0;
+    gView.scrollLeft = 0;
+    gCurrentTestIndex = -1;
+    growUpTimeoutPrefs();
+    ok(true, "WARNING: retry current test-list...");
+    gTimer = setTimeout(runNextTest, 0);
+  } else {
+    ok(false, "Failed by unexpected timeout");
+    finish();
+  }
+}
+
+function fireWheelScrollEvent(aForward)
+{
+  gIgnoreScrollEvent = false;
+  var event = { deltaY: aForward ? 4.0 : -4.0,
+                deltaMode: WheelEvent.DOM_DELTA_LINE };
+  sendWheelAndPaint(gView, 5, 5, event, function() {
+    // No callback - we're just forcing the refresh driver to tick.
+  }, window);
+}
+
+function onScrollView(aEvent)
+{
+  if (gIgnoreScrollEvent)
+    return;
+  gIgnoreScrollEvent = true;
+  clearTimer();
+  ok(gTests[gCurrentTestIndex].shouldScroll, "The view is scrolled");
+  gTimer = setTimeout(runNextTest, 0);
+}
+
+function onMouseScrollFailed(aEvent)
+{
+  clearTimer();
+  gIgnoreScrollEvent = true;
+  ok(!gTests[gCurrentTestIndex].shouldScroll, "The view is not scrolled");
+  if (!gTests[gCurrentTestIndex].shouldScroll)
+    gBody.removeChild(gView);
+  runNextTest();
+}
+
+function onTransactionTimeout(aEvent)
+{
+  if (!gTimer)
+    return;
+  gIgnoreScrollEvent = true;
+  retryAllTests();
+}
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/window_bug522217.xhtml b/widget/tests/window_bug522217.xhtml
new file mode 100644
index 0000000000..80eb4b6e5a
--- /dev/null
+++ b/widget/tests/window_bug522217.xhtml
@@ -0,0 +1,80 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="Mozilla Bug 522217"
+  onload="start();"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js" />
+
+<body xmlns="http://www.w3.org/1999/xhtml" id="body">
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+function ok(aCondition, aMessage)
+{
+  window.arguments[0].SimpleTest.ok(aCondition, aMessage);
+}
+
+function is(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.is(aLeft, aRight, aMessage);
+}
+
+function isnot(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.isnot(aLeft, aRight, aMessage);
+}
+
+function executeSoon() {
+  return new Promise(resolve => {
+    window.arguments[0].SimpleTest.executeSoon(resolve);
+  });
+}
+
+function waitForEvent(obj, name) {
+  return new Promise(resolve => {
+    obj.addEventListener(name, resolve, { once: true });
+  });
+}
+
+async function start() {
+  await waitForEvent(window, "focus");
+  var oldOuterWidth = window.outerWidth, oldOuterHeight = window.outerHeight;
+  var oldInnerWidth = window.innerWidth, oldInnerHeight = window.innerHeight;
+  document.documentElement.setAttribute("chromemargin", "0,0,0,0");
+
+  await executeSoon();
+  is(window.outerWidth, oldOuterWidth, "chromemargin shouldn't change the window's outerWidth");
+  is(window.outerHeight, oldOuterHeight, "chromemargin shouldn't change the window's outerHeight");
+  is(window.innerWidth, oldOuterWidth, "if chromemargin is set, innerWidth and outerWidth should be the same");
+  is(window.innerHeight, oldOuterHeight, "if chromemargin is set, innerHeight and outerHeight should be the same");
+
+  // Wait for going full screen and back.
+  let sizemodeChange = waitForEvent(window, "sizemodechange");
+  window.fullScreen = true;
+  await sizemodeChange;
+  sizemodeChange = waitForEvent(window, "sizemodechange");
+  window.fullScreen = false;
+  await sizemodeChange;
+  is(window.outerWidth, oldOuterWidth, "wrong outerWidth after fullscreen mode");
+  is(window.outerHeight, oldOuterHeight, "wrong outerHeight after fullscreen mode");
+  is(window.innerWidth, oldOuterWidth, "wrong innerWidth after fullscreen mode");
+  is(window.innerHeight, oldOuterHeight, "wrong innerHeight after fullscreen mode");
+  document.documentElement.removeAttribute("chromemargin");
+
+  await executeSoon();
+  is(window.outerWidth, oldOuterWidth, "wrong outerWidth after removing chromemargin");
+  is(window.outerHeight, oldOuterHeight, "wrong outerHeight after removing chromemargin");
+  is(window.innerWidth, oldInnerWidth, "wrong innerWidth after removing chromemargin");
+  is(window.innerHeight, oldInnerHeight, "wrong innerHeight after removing chromemargin");
+  window.arguments[0].SimpleTest.finish();
+  window.close();
+}
+
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/window_bug538242.xhtml b/widget/tests/window_bug538242.xhtml
new file mode 100644
index 0000000000..fb878b1383
--- /dev/null
+++ b/widget/tests/window_bug538242.xhtml
@@ -0,0 +1,3 @@
+<?xml version="1.0"?>
+<window title="Window for Test for Mozilla Bug 538242"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"/>
diff --git a/widget/tests/window_bug593307_centerscreen.xhtml b/widget/tests/window_bug593307_centerscreen.xhtml
new file mode 100644
index 0000000000..dd73e42f84
--- /dev/null
+++ b/widget/tests/window_bug593307_centerscreen.xhtml
@@ -0,0 +1,26 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="Mozilla Bug 593307"
+  width="100" height="100"
+  onload="onload();"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js" />
+
+<body xmlns="http://www.w3.org/1999/xhtml" id="body">
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+function onload()
+{
+  var SimpleTest = window.opener.SimpleTest;
+  SimpleTest.ok(window.screenX >= 0, "centerscreen window should not start offscreen (X coordinate): " + window.screenX);
+  SimpleTest.ok(window.screenY >= 0, "centerscreen window should not start offscreen (Y coordinate): " + window.screenY);
+  window.opener.finished();
+}
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/window_bug593307_offscreen.xhtml b/widget/tests/window_bug593307_offscreen.xhtml
new file mode 100644
index 0000000000..10ab701a55
--- /dev/null
+++ b/widget/tests/window_bug593307_offscreen.xhtml
@@ -0,0 +1,35 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="Mozilla Bug 593307"
+  width="100" height="100"
+  onload="onLoad();"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js" />
+
+<body xmlns="http://www.w3.org/1999/xhtml" id="body">
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+var centerscreen = null;
+var SimpleTest = window.arguments[0];
+var finish = window.arguments[1];
+
+function onLoad()
+{
+  setTimeout(() => {
+    centerscreen = window.openDialog('window_bug593307_centerscreen.xhtml','', 'chrome,centerscreen,dependent,dialog=no');
+  }, 0);
+}
+
+function finished() {
+  centerscreen.close();
+  finish();
+}
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/window_composition_text_querycontent.xhtml b/widget/tests/window_composition_text_querycontent.xhtml
new file mode 100644
index 0000000000..db3b10ea30
--- /dev/null
+++ b/widget/tests/window_composition_text_querycontent.xhtml
@@ -0,0 +1,10923 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css"
+                 type="text/css"?>
+<window title="Testing composition, text and query content events"
+  xmlns:html="http://www.w3.org/1999/xhtml"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js" />
+  <script src="chrome://mochikit/content/tests/SimpleTest/WindowSnapshot.js" />
+
+  <panel id="panel" hidden="true" orient="vertical">
+    <vbox id="vbox">
+      <html:textarea id="textbox" cols="20" rows="4" style="font-size: 36px;"/>
+    </vbox>
+  </panel>
+
+<body  xmlns="http://www.w3.org/1999/xhtml">
+<div id="display">
+<div id="div" style="margin: 0; padding: 0; font-size: 36px;">Here is a text frame.</div>
+<textarea style="margin: 0; font-family: -moz-fixed;" id="textarea" cols="20" rows="4"></textarea><br/>
+<iframe id="iframe" width="300" height="150"
+        src="data:text/html,&lt;textarea id='textarea' cols='20' rows='4'&gt;&lt;/textarea&gt;"></iframe><br/>
+<iframe id="iframe2" width="300" height="150"
+        src="data:text/html,&lt;body onload='document.designMode=%22on%22'&gt;body content&lt;/body&gt;"></iframe><br/>
+<iframe id="iframe3" width="300" height="150"
+        src="data:text/html,&lt;body onload='document.designMode=%22on%22'&gt;body content&lt;/body&gt;"></iframe><br/>
+<iframe id="iframe4" width="300" height="150"
+        src="data:text/html,&lt;div contenteditable id='contenteditable'&gt;&lt;/div&gt;"></iframe><br/>
+<!--
+  NOTE: the width for the next two iframes is chosen to be small enough to make
+  the Show Password button (for type=password) be outside the viewport so that
+  it doesn't affect the rendering compared to the type=text control.
+  But still large enough to comfortably fit the input values we test.
+-->
+<iframe id="iframe5" style="width:10ch" height="50" src="data:text/html,&lt;input id='input'&gt;"></iframe>
+<iframe id="iframe6" style="width:10ch" height="50" src="data:text/html,&lt;input id='password' type='password'&gt;"></iframe><br/>
+<iframe id="iframe7" width="300" height="150"
+        src="data:text/html,&lt;span contenteditable id='contenteditable'&gt;&lt;/span&gt;"></iframe><br/>
+<input id="input" type="text"/><br/>
+<input id="password" type="password"/><br/>
+</div>
+<div id="content" style="display: none">
+
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+function ok(aCondition, aMessage)
+{
+  window.arguments[0].SimpleTest.ok(aCondition, aMessage);
+}
+
+function is(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.is(aLeft, aRight, aMessage);
+}
+
+function isnot(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.isnot(aLeft, aRight, aMessage);
+}
+
+function isfuzzy(aLeft, aRight, aEpsilon, aMessage) {
+  window.arguments[0].SimpleTest.isfuzzy(aLeft, aRight, aEpsilon, aMessage);
+}
+
+function todo(aCondition, aMessage)
+{
+  window.arguments[0].SimpleTest.todo(aCondition, aMessage);
+}
+
+function todo_is(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.todo_is(aLeft, aRight, aMessage);
+}
+
+function todo_isnot(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.todo_isnot(aLeft, aRight, aMessage);
+}
+
+function isSimilarTo(aLeft, aRight, aAllowedDifference, aMessage)
+{
+  if (Math.abs(aLeft - aRight) <= aAllowedDifference) {
+    ok(true, aMessage);
+  } else {
+    ok(false, aMessage + ", got=" + aLeft + ", expected=" + (aRight - aAllowedDifference) + "~" + (aRight + aAllowedDifference));
+  }
+}
+
+function isGreaterThan(aLeft, aRight, aMessage)
+{
+  ok(aLeft > aRight, aMessage + ", got=" + aLeft + ", expected minimum value=" + aRight);
+}
+
+/**
+ * synthesizeSimpleCompositionChange synthesizes a composition which has only
+ * one clause and put caret end of it.
+ *
+ * @param aComposition  string or object.  If string, it's treated as
+ *                      composition string whose attribute is
+ *                      COMPOSITION_ATTR_RAW_CLAUSE.
+ *                      If object, it must have .string whose type is "string".
+ *                      Additionally, .attr can be specified if you'd like to
+ *                      use the other attribute instead of
+ *                      COMPOSITION_ATTR_RAW_CLAUSE.
+ */
+function synthesizeSimpleCompositionChange(aComposition, aWindow, aCallback) {
+  const comp = (() => {
+    if (typeof aComposition == "string") {
+      return { string: aComposition, attr: COMPOSITION_ATTR_RAW_CLAUSE };
+    }
+    return {
+      string: aComposition.string,
+      attr: aComposition.attr === undefined
+        ? COMPOSITION_ATTR_RAW_CLAUSE
+        : aComposition.attr
+    };
+  })();
+  synthesizeCompositionChange(
+    {
+      composition: {
+        string: comp.string,
+        clauses: [
+          { length: comp.string.length, attr: comp.attr },
+        ],
+      },
+      caret: { start: comp.string.length, length: 0 },
+    },
+    aWindow,
+    aCallback
+  );
+}
+
+
+var div = document.getElementById("div");
+var textarea = document.getElementById("textarea");
+var panel = document.getElementById("panel");
+var textbox = document.getElementById("textbox");
+var iframe = document.getElementById("iframe");
+var iframe2 = document.getElementById("iframe2");
+var iframe3 = document.getElementById("iframe3");
+var contenteditable;
+var windowOfContenteditable;
+var contenteditableBySpan;
+var windowOfContenteditableBySpan;
+var input = document.getElementById("input");
+var password = document.getElementById("password");
+var textareaInFrame;
+
+const nsITextInputProcessorCallback = Ci.nsITextInputProcessorCallback;
+const nsIInterfaceRequestor = Ci.nsIInterfaceRequestor;
+const nsIWebNavigation = Ci.nsIWebNavigation;
+const nsIDocShell = Ci.nsIDocShell;
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+
+function waitForTick() {
+  return new Promise(resolve => { SimpleTest.executeSoon(resolve); });
+}
+
+async function waitForEventLoops(aTimes)
+{
+  for (let i = 1; i < aTimes; i++) {
+    await waitForTick();
+  }
+  await new Promise(resolve => { setTimeout(resolve, 20); });
+}
+
+function getEditor(aNode)
+{
+  return aNode.editor;
+}
+
+function getHTMLEditorIMESupport(aWindow)
+{
+  return aWindow.docShell.editor;
+}
+
+const kIsWin = (navigator.platform.indexOf("Win") == 0);
+const kIsMac = (navigator.platform.indexOf("Mac") == 0);
+
+const kLFLen = (kIsWin && false) ? 2 : 1;
+const kLF = (kIsWin && false) ? "\r\n" : "\n";
+
+function checkQueryContentResult(aResult, aMessage)
+{
+  ok(aResult, aMessage + ": the result is null");
+  if (!aResult) {
+    return false;
+  }
+  ok(aResult.succeeded, aMessage + ": the query content failed");
+  return aResult.succeeded;
+}
+
+function checkContent(aExpectedText, aMessage, aID)
+{
+  if (!aID) {
+    aID = "";
+  }
+  let textContent = synthesizeQueryTextContent(0, 100);
+  if (!checkQueryContentResult(textContent, aMessage +
+                               ": synthesizeQueryTextContent " + aID)) {
+    return false;
+  }
+  is(textContent.text, aExpectedText,
+     aMessage + ": composition string is wrong " + aID);
+  return textContent.text == aExpectedText;
+}
+
+function checkContentRelativeToSelection(aRelativeOffset, aLength, aExpectedOffset, aExpectedText, aMessage, aID)
+{
+  if (!aID) {
+    aID = "";
+  }
+  aMessage += " (aRelativeOffset=" + aRelativeOffset + "): "
+  let textContent = synthesizeQueryTextContent(aRelativeOffset, aLength, true);
+  if (!checkQueryContentResult(textContent, aMessage +
+                               "synthesizeQueryTextContent " + aID)) {
+    return false;
+  }
+  is(textContent.offset, aExpectedOffset,
+     aMessage + "offset is wrong " + aID);
+  is(textContent.text, aExpectedText,
+     aMessage + "text is wrong " + aID);
+  return textContent.offset == aExpectedOffset &&
+         textContent.text == aExpectedText;
+}
+
+function checkSelection(aExpectedOffset, aExpectedText, aMessage, aID)
+{
+  if (!aID) {
+    aID = "";
+  }
+  let selectedText = synthesizeQuerySelectedText();
+  if (!checkQueryContentResult(selectedText, aMessage +
+                               ": synthesizeQuerySelectedText " + aID)) {
+    return false;
+  }
+  if (aExpectedOffset === null) {
+    is(
+      selectedText.notFound,
+      true,
+      `${aMessage}: selection should not be found ${aID}`
+    );
+    return selectedText.notFound;
+  }
+
+  is(
+    selectedText.notFound,
+    false,
+    `${aMessage}: selection should be found ${aID}`
+  );
+  if (selectedText.notFound) {
+    return false;
+  }
+  is(
+    selectedText.offset,
+    aExpectedOffset,
+    `${aMessage}: selection offset should be ${aExpectedOffset} ${aID}`
+  );
+  is(
+    selectedText.text,
+    aExpectedText,
+    `${aMessage}: selected text should be "${aExpectedText}" ${aID}`
+  );
+  return selectedText.offset == aExpectedOffset &&
+         selectedText.text == aExpectedText;
+}
+
+function checkIMESelection(
+  aSelectionType,
+  aExpectedFound,
+  aExpectedOffset,
+  aExpectedText,
+  aMessage,
+  aID,
+  aToDo = {}
+) {
+  if (!aID) {
+    aID = "";
+  }
+  aMessage += " (" + aSelectionType + ")";
+  let {
+    notFound = is,
+    offset = is,
+    text = is,
+  } = aToDo;
+  let selectionType = 0;
+  switch (aSelectionType) {
+    case "RawClause":
+      selectionType = QUERY_CONTENT_FLAG_SELECTION_IME_RAWINPUT;
+      break;
+    case "SelectedRawClause":
+      selectionType = QUERY_CONTENT_FLAG_SELECTION_IME_SELECTEDRAWTEXT;
+      break;
+    case "ConvertedClause":
+      selectionType = QUERY_CONTENT_FLAG_SELECTION_IME_CONVERTEDTEXT;
+      break;
+    case "SelectedClause":
+      selectionType = QUERY_CONTENT_FLAG_SELECTION_IME_SELECTEDCONVERTEDTEXT;
+      break;
+    default:
+      ok(false, aMessage + ": invalid selection type, " + aSelectionType);
+  }
+  isnot(selectionType, 0, aMessage + ": wrong value");
+  let selectedText = synthesizeQuerySelectedText(selectionType);
+  if (!checkQueryContentResult(selectedText, aMessage +
+                               ": synthesizeQuerySelectedText " + aID)) {
+    return false;
+  }
+  notFound(
+    selectedText.notFound,
+    !aExpectedFound,
+    `${aMessage}: selection should ${
+      aExpectedFound ? "" : "not"
+    } be found ${aID}`);
+  if (selectedText.notFound) {
+    return selectedText.notFound == !aExpectedFound;
+  }
+
+  offset(
+    selectedText.offset,
+    aExpectedOffset,
+    `${aMessage}: selection offset is wrong ${aID}`
+  );
+  text(
+    selectedText.text,
+    aExpectedText,
+    `${aMessage}: selected text is wrong ${aID}`
+  );
+  return selectedText.offset == aExpectedOffset &&
+         selectedText.text == aExpectedText;
+}
+
+function checkRect(aRect, aExpectedRect, aMessage)
+{
+  is(aRect.left, aExpectedRect.left, aMessage + ": left is wrong");
+  is(aRect.top, aExpectedRect.top, aMessage + " top is wrong");
+  is(aRect.width, aExpectedRect.width, aMessage + ": width is wrong");
+  is(aRect.height, aExpectedRect.height, aMessage + ": height is wrong");
+  return aRect.left == aExpectedRect.left &&
+         aRect.top == aExpectedRect.top &&
+         aRect.width == aExpectedRect.width &&
+         aRect.height == aExpectedRect.height;
+}
+
+function checkRectFuzzy(aRect, aExpectedRect, aEpsilon, aMessage) {
+  isfuzzy(aRect.left, aExpectedRect.left, aEpsilon.left, aMessage + ": left is wrong");
+  isfuzzy(aRect.top, aExpectedRect.top, aEpsilon.top, aMessage + " top is wrong");
+  isfuzzy(aRect.width, aExpectedRect.width, aEpsilon.width, aMessage + ": width is wrong");
+  isfuzzy(aRect.height, aExpectedRect.height, aEpsilon.height, aMessage + ": height is wrong");
+  return (aRect.left >= aExpectedRect.left - aEpsilon.left &&
+          aRect.left <= aExpectedRect.left + aEpsilon.left) &&
+         (aRect.top >= aExpectedRect.top - aEpsilon.top &&
+          aRect.top <= aExpectedRect.top + aEpsilon.top) &&
+         (aRect.width >= aExpectedRect.width - aEpsilon.width &&
+          aRect.width <= aExpectedRect.width + aEpsilon.width) &&
+         (aRect.height >= aExpectedRect.height - aEpsilon.height &&
+          aRect.height <= aExpectedRect.height + aEpsilon.height);
+}
+
+function getRectArray(aQueryTextRectArrayResult) {
+  let rects = [];
+  for (let i = 0; ; i++) {
+    let rect = { left: {}, top: {}, width: {}, height: {} };
+    try {
+      aQueryTextRectArrayResult.getCharacterRect(i, rect.left, rect.top, rect.width, rect.height);
+    } catch (e) {
+      break;
+    }
+    rects.push({
+      left: rect.left.value,
+      top: rect.top.value,
+      width: rect.width.value,
+      height: rect.height.value,
+    });
+  }
+  return rects;
+}
+
+function checkRectArray(aQueryTextRectArrayResult, aExpectedTextRectArray, aMessage)
+{
+  for (let i = 1; i < aExpectedTextRectArray.length; ++i) {
+    let rect = { left: {}, top: {}, width: {}, height: {} };
+    try {
+      aQueryTextRectArrayResult.getCharacterRect(i, rect.left, rect.top, rect.width, rect.height);
+    } catch (e) {
+      ok(false, aMessage + ": failed to retrieve " + i + "th rect (" + e + ")");
+      return false;
+    }
+    function toRect(aRect)
+    {
+      return { left: aRect.left.value, top: aRect.top.value, width: aRect.width.value, height: aRect.height.value };
+    }
+    if (!checkRect(toRect(rect), aExpectedTextRectArray[i], aMessage + " " + i + "th rect")) {
+      return false;
+    }
+  }
+  return true;
+}
+
+function checkRectContainsRect(aRect, aContainer, aMessage)
+{
+  let container = { left: Math.ceil(aContainer.left),
+                    top:  Math.ceil(aContainer.top),
+                    width: Math.floor(aContainer.width),
+                    height: Math.floor(aContainer.height) };
+
+  let ret = container.left <= aRect.left &&
+            container.top <= aRect.top &&
+            container.left + container.width >= aRect.left + aRect.width &&
+            container.top + container.height >= aRect.top + aRect.height;
+  ret = ret && aMessage;
+  ok(ret, aMessage + " container={ left=" + container.left + ", top=" +
+     container.top + ", width=" + container.width + ", height=" +
+     container.height + " } rect={ left=" + aRect.left + ", top=" + aRect.top +
+     ", width=" + aRect.width + ", height=" + aRect.height + " }");
+  return ret;
+}
+
+// eslint-disable-next-line complexity
+function runUndoRedoTest()
+{
+  textarea.value = "";
+  textarea.focus();
+
+  // input raw characters
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306D",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "," },
+    });
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306D\u3053",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 },
+      "key": { key: "b" },
+    });
+
+  // convert
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u732B",
+        "clauses":
+        [
+          { "length": 1,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: " " },
+    });
+
+  // commit
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  // input raw characters
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u307E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "j" },
+    });
+
+  // cancel the composition
+  synthesizeComposition({ type: "compositioncommit", data: "", key: { key: "KEY_Escape" } });
+
+  // input raw characters
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3080",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "]" },
+    });
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3080\u3059",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 },
+      "key": { key: "r" },
+    });
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3080\u3059\u3081",
+        "clauses":
+        [
+          { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 3, "length": 0 },
+      "key": { key: "/" },
+    });
+
+  // convert
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u5A18",
+        "clauses":
+        [
+          { "length": 1,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: " " },
+    });
+
+  // commit
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  sendString(" meant");
+  synthesizeKey("KEY_Backspace");
+  synthesizeKey("s \"cat-girl\". She is a ");
+
+  // input raw characters
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3088",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "9" },
+    });
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3088\u3046",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 },
+      "key": { key: "4" },
+    });
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3088\u3046\u304b",
+        "clauses":
+        [
+          { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 3, "length": 0 },
+      "key": { key: "t" },
+    });
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3088\u3046\u304b\u3044",
+        "clauses":
+        [
+          { "length": 4, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 4, "length": 0 },
+      "key": { key: "e" },
+    });
+
+  // convert
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u5996\u602a",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 },
+      "key": { key: " " },
+    });
+
+  // commit
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "Enter" } });
+
+  synthesizeKey("KEY_Backspace", {repeat: 12});
+
+  let i = 0;
+  if (!checkContent("\u732B\u5A18 means \"cat-girl\".",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(20, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true});
+
+  if (!checkContent("\u732B\u5A18 means \"cat-girl\". She is a \u5996\u602A",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(32, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true});
+
+  if (!checkContent("\u732B\u5A18 means \"cat-girl\". She is a ",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(30, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true});
+
+  if (!checkContent("\u732B\u5A18 mean",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(7, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true});
+
+  if (!checkContent("\u732B\u5A18 meant",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(8, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true});
+
+  if (!checkContent("\u732B\u5A18",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(2, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true});
+
+  if (!checkContent("\u732B",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(1, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true});
+
+  // XXX this is unexpected behavior, see bug 258291
+  if (!checkContent("\u732B",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(1, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true});
+
+  if (!checkContent("",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(0, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true});
+
+  if (!checkContent("",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(0, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true, shiftKey: true});
+
+  if (!checkContent("\u732B",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(1, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true, shiftKey: true});
+
+  // XXX this is unexpected behavior, see bug 258291
+  if (!checkContent("\u732B",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(1, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true, shiftKey: true});
+
+  if (!checkContent("\u732B\u5A18",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(2, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true, shiftKey: true});
+
+  if (!checkContent("\u732B\u5A18 meant",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(8, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true, shiftKey: true});
+
+  if (!checkContent("\u732B\u5A18 mean",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(7, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true, shiftKey: true});
+
+  if (!checkContent("\u732B\u5A18 means \"cat-girl\". She is a ",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(30, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true, shiftKey: true});
+
+  if (!checkContent("\u732B\u5A18 means \"cat-girl\". She is a \u5996\u602A",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(32, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true, shiftKey: true});
+
+  if (!checkContent("\u732B\u5A18 means \"cat-girl\".",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(20, "", "runUndoRedoTest", "#" + i)) {
+    return;
+  }
+
+  synthesizeKey("Z", {accelKey: true, shiftKey: true});
+
+  if (!checkContent("\u732B\u5A18 means \"cat-girl\".",
+                    "runUndoRedoTest", "#" + ++i) ||
+      !checkSelection(20, "", "runUndoRedoTest", "#" + i)) {
+    // eslint-disable-next-line no-useless-return
+    return;
+  }
+}
+
+function checkInputEvent(aEvent, aIsComposing, aInputType, aData, aTargetRanges, aDescription) {
+  if (aEvent.type !== "input" && aEvent.type !== "beforeinput") {
+    throw new Error(`${aDescription}: "${aEvent.type}" is not InputEvent`);
+  }
+  ok(InputEvent.isInstance(aEvent), `"${aEvent.type}" event should be dispatched with InputEvent interface: ${aDescription}`);
+  let cancelable = aEvent.type === "beforeinput" &&
+                   aInputType !== "insertCompositionText" &&
+                   aInputType !== "deleteCompositionText";
+  is(aEvent.cancelable, cancelable, `"${aEvent.type}" event should ${cancelable ? "be" : "be never"} cancelable: ${aDescription}`);
+  is(aEvent.bubbles, true, `"${aEvent.type}" event should always bubble: ${aDescription}`);
+  is(aEvent.isComposing, aIsComposing, `isComposing of "${aEvent.type}" event should be ${aIsComposing}: ${aDescription}`);
+  is(aEvent.inputType, aInputType, `inputType of "${aEvent.type}" event should be "${aInputType}": ${aDescription}`);
+  is(aEvent.data, aData, `data of "${aEvent.type}" event should be ${aData}: ${aDescription}`);
+  is(aEvent.dataTransfer, null, `dataTransfer of "${aEvent.type}" event should be null: ${aDescription}`);
+  let targetRanges = aEvent.getTargetRanges();
+  if (aTargetRanges.length === 0) {
+    is(targetRanges.length, 0,
+       `getTargetRange() of "${aEvent.type}" event should return empty array: ${aDescription}`);
+  } else {
+    is(targetRanges.length, aTargetRanges.length,
+       `getTargetRange() of "${aEvent.type}" event should return static range array: ${aDescription}`);
+    if (targetRanges.length == aTargetRanges.length) {
+      for (let i = 0; i < targetRanges.length; i++) {
+        is(targetRanges[i].startContainer, aTargetRanges[i].startContainer,
+           `startContainer of getTargetRanges()[${i}] of "${aEvent.type}" event does not match: ${aDescription}`);
+        is(targetRanges[i].startOffset, aTargetRanges[i].startOffset,
+           `startOffset of getTargetRanges()[${i}] of "${aEvent.type}" event does not match: ${aDescription}`);
+        is(targetRanges[i].endContainer, aTargetRanges[i].endContainer,
+           `endContainer of getTargetRanges()[${i}] of "${aEvent.type}" event does not match: ${aDescription}`);
+        is(targetRanges[i].endOffset, aTargetRanges[i].endOffset,
+           `endOffset of getTargetRanges()[${i}] of "${aEvent.type}" event does not match: ${aDescription}`);
+      }
+    }
+  }
+}
+
+function runCompositionCommitAsIsTest()
+{
+  textarea.focus();
+
+  let result = [];
+  function clearResult()
+  {
+    result = [];
+  }
+
+  function handler(aEvent)
+  {
+    result.push(aEvent);
+  }
+
+  textarea.addEventListener("compositionupdate", handler, true);
+  textarea.addEventListener("compositionend", handler, true);
+  textarea.addEventListener("beforeinput", handler, true);
+  textarea.addEventListener("input", handler, true);
+  textarea.addEventListener("text", handler, true);
+
+  // compositioncommitasis with composing string.
+  textarea.value = "";
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "a" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitAsIsTest: textarea doesn't have composition string #1");
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "Enter" } });
+
+  is(result.length, 4,
+     "runCompositionCommitAsIsTest: 4 events should be fired after dispatching compositioncommitasis #1");
+  is(result[0].type, "text",
+     "runCompositionCommitAsIsTest: text should be fired after dispatching compositioncommitasis because it's dispatched when there is composing string #1");
+  is(result[1].type, "beforeinput",
+     "runCompositionCommitAsIsTest: beforeinput should be fired after dispatching compositioncommitasis because it's dispatched when there is composing string #1");
+  checkInputEvent(result[1], true, "insertCompositionText", "\u3042", [],
+                  "runCompositionCommitAsIsTest: after dispatching compositioncommitasis #1");
+  is(result[2].type, "compositionend",
+     "runCompositionCommitAsIsTest: compositionend should be fired after dispatching compositioncommitasis #1");
+  is(result[3].type, "input",
+     "runCompositionCommitAsIsTest: input should be fired after dispatching compositioncommitasis #1");
+  checkInputEvent(result[3], false, "insertCompositionText", "\u3042", [],
+                  "runCompositionCommitAsIsTest: after dispatching compositioncommitasis #1");
+  is(textarea.value, "\u3042", "runCompositionCommitAsIsTest: textarea doesn't have committed string #1");
+
+  // compositioncommitasis with committed string.
+  textarea.value = "";
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "a" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitAsIsTest: textarea doesn't have composition string #2");
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "KEY_Enter", type: "keydown" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitAsIsTest: textarea doesn't have committed string #2");
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter", type: "keyup" } });
+
+  is(result.length, 2,
+     "runCompositionCommitAsIsTest: 2 events should be fired after dispatching compositioncommitasis #2");
+  // XXX Do we need a "beforeinput" event here? Not sure.
+  is(result[0].type, "compositionend",
+     "runCompositionCommitAsIsTest: compositionend should be fired after dispatching compositioncommitasis #2");
+  is(result[1].type, "input",
+     "runCompositionCommitAsIsTest: input should be fired after dispatching compositioncommitasis #2");
+  checkInputEvent(result[1], false, "insertCompositionText", "\u3042", [],
+                  "runCompositionCommitAsIsTest: after dispatching compositioncommitasis #2");
+  is(textarea.value, "\u3042", "runCompositionCommitAsIsTest: textarea doesn't have committed string #2");
+
+  // compositioncommitasis with committed string.
+  textarea.value = "";
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "a" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitAsIsTest: textarea doesn't have composition string #3");
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+      "caret": { "start": 0, "length": 0 },
+      "key": { key: "KEY_Escape", type: "keydown" },
+    });
+  is(textarea.value, "", "runCompositionCommitAsIsTest: textarea has non-empty composition string #3");
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Escape", type: "keyup" } });
+
+  is(result.length, 2,
+     "runCompositionCommitAsIsTest: 2 events should be fired after dispatching compositioncommitasis #3");
+  // XXX Do we need a "beforeinput" event here? Not sure.
+  is(result[0].type, "compositionend",
+     "runCompositionCommitAsIsTest: compositionend shouldn't be fired after dispatching compositioncommitasis #3");
+  is(result[1].type, "input",
+     "runCompositionCommitAsIsTest: input should be fired after dispatching compositioncommitasis #3");
+  checkInputEvent(result[1], false, "insertCompositionText", "", [],
+                  "runCompositionCommitAsIsTest: after dispatching compositioncommitasis #3");
+  is(textarea.value, "", "runCompositionCommitAsIsTest: textarea doesn't have committed string #3");
+
+  textarea.removeEventListener("compositionupdate", handler, true);
+  textarea.removeEventListener("compositionend", handler, true);
+  textarea.removeEventListener("beforeinput", handler, true);
+  textarea.removeEventListener("input", handler, true);
+  textarea.removeEventListener("text", handler, true);
+}
+
+function runCompositionCommitTest()
+{
+  textarea.focus();
+
+  let result = [];
+  function clearResult()
+  {
+    result = [];
+  }
+
+  function handler(aEvent)
+  {
+    result.push(aEvent);
+  }
+
+  textarea.addEventListener("compositionupdate", handler, true);
+  textarea.addEventListener("compositionend", handler, true);
+  textarea.addEventListener("beforeinput", handler, true);
+  textarea.addEventListener("input", handler, true);
+  textarea.addEventListener("text", handler, true);
+
+  // compositioncommit with different composing string.
+  textarea.value = "";
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "a", type: "keydown" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitTest: textarea doesn't have composition string #1");
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommit", data: "\u3043", key: { key: "a", type: "keyup" } });
+
+  is(result.length, 5,
+     "runCompositionCommitTest: 5 events should be fired after dispatching compositioncommit #1");
+  is(result[0].type, "compositionupdate",
+     "runCompositionCommitTest: compositionupdate should be fired after dispatching compositioncommit because it's dispatched when there is composing string #1");
+  is(result[1].type, "text",
+     "runCompositionCommitTest: text should be fired after dispatching compositioncommit #1");
+  is(result[2].type, "beforeinput",
+     "runCompositionCommitTest: beforeinput should be fired after dispatching compositioncommit because it's dispatched when there is composing string #1");
+  checkInputEvent(result[2], true, "insertCompositionText", "\u3043", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #1");
+  is(result[3].type, "compositionend",
+     "runCompositionCommitTest: compositionend should be fired after dispatching compositioncommit #1");
+  is(result[4].type, "input",
+     "runCompositionCommitTest: input should be fired after dispatching compositioncommit #1");
+  checkInputEvent(result[4], false, "insertCompositionText", "\u3043", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #1");
+  is(textarea.value, "\u3043", "runCompositionCommitTest: textarea doesn't have committed string #1");
+
+  // compositioncommit with different committed string when there is already committed string
+  textarea.value = "";
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "a" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitTest: textarea doesn't have composition string #2");
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "KEY_Enter", type: "keydown" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitTest: textarea doesn't have committed string #2");
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommit", data: "\u3043", key: { key: "KEY_Enter", type: "keyup" } });
+
+  is(result.length, 5,
+     "runCompositionCommitTest: 5 events should be fired after dispatching compositioncommit #2");
+  is(result[0].type, "compositionupdate",
+     "runCompositionCommitTest: compositionupdate should be fired after dispatching compositioncommit #2");
+  is(result[1].type, "text",
+     "runCompositionCommitTest: text should be fired after dispatching compositioncommit #2");
+  is(result[2].type, "beforeinput",
+     "runCompositionCommitTest: beforeinput should be fired after dispatching compositioncommit #2");
+  checkInputEvent(result[2], true, "insertCompositionText", "\u3043", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #2");
+  is(result[3].type, "compositionend",
+     "runCompositionCommitTest: compositionend should be fired after dispatching compositioncommit #2");
+  is(result[4].type, "input",
+     "runCompositionCommitTest: input should be fired after dispatching compositioncommit #2");
+  checkInputEvent(result[4], false, "insertCompositionText", "\u3043", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #2");
+  is(textarea.value, "\u3043", "runCompositionCommitTest: textarea doesn't have committed string #2");
+
+  // compositioncommit with empty composition string.
+  textarea.value = "";
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "a" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitTest: textarea doesn't have composition string #3");
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+      "caret": { "start": 0, "length": 0 },
+      "key": { key: "KEY_Enter", type: "keydown" },
+    });
+  is(textarea.value, "", "runCompositionCommitTest: textarea has non-empty composition string #3");
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommit", data: "\u3043", key: { key: "KEY_Enter", type: "keyup" } });
+
+  is(result.length, 5,
+     "runCompositionCommitTest: 5 events should be fired after dispatching compositioncommit #3");
+  is(result[0].type, "compositionupdate",
+     "runCompositionCommitTest: compositionupdate should be fired after dispatching compositioncommit #3");
+  is(result[1].type, "text",
+     "runCompositionCommitTest: text should be fired after dispatching compositioncommit #3");
+  is(result[2].type, "beforeinput",
+     "runCompositionCommitTest: beforeinput should be fired after dispatching compositioncommit #3");
+  checkInputEvent(result[2], true, "insertCompositionText", "\u3043", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #3");
+  is(result[3].type, "compositionend",
+     "runCompositionCommitTest: compositionend should be fired after dispatching compositioncommit #3");
+  is(result[4].type, "input",
+     "runCompositionCommitTest: input should be fired after dispatching compositioncommit #3");
+  checkInputEvent(result[4], false, "insertCompositionText", "\u3043", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #3");
+  is(textarea.value, "\u3043", "runCompositionCommitTest: textarea doesn't have committed string #3");
+
+  // inserting empty string with simple composition.
+  textarea.value = "abc";
+  textarea.setSelectionRange(3, 3);
+  synthesizeComposition({ type: "compositionstart" });
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommit", data: "" });
+
+  is(result.length, 4,
+     "runCompositionCommitTest: 4 events should be fired when inserting empty string with composition");
+  is(result[0].type, "text",
+     "runCompositionCommitTest: text should be fired when inserting empty string with composition");
+  is(result[1].type, "beforeinput",
+     "runCompositionCommitTest: beforeinput should be fired when inserting empty string with composition");
+  checkInputEvent(result[1], true, "insertCompositionText", "", [],
+                  "runCompositionCommitTest: when inserting empty string with composition");
+  is(result[2].type, "compositionend",
+     "runCompositionCommitTest: compositionend should be fired when inserting empty string with composition");
+  is(result[3].type, "input",
+     "runCompositionCommitTest: input should be fired when inserting empty string with composition");
+  checkInputEvent(result[3], false, "insertCompositionText", "", [],
+                  "runCompositionCommitTest: when inserting empty string with composition");
+  is(textarea.value, "abc",
+     "runCompositionCommitTest: textarea should keep original value when inserting empty string with composition");
+
+  // replacing selection with empty string with simple composition.
+  textarea.value = "abc";
+  textarea.setSelectionRange(0, 3);
+  synthesizeComposition({ type: "compositionstart" });
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommit", data: "" });
+
+  is(result.length, 4,
+     "runCompositionCommitTest: 4 events should be fired when replacing with empty string with composition");
+  is(result[0].type, "text",
+     "runCompositionCommitTest: text should be fired when replacing with empty string with composition");
+  is(result[1].type, "beforeinput",
+     "runCompositionCommitTest: beforeinput should be fired when replacing with empty string with composition");
+  checkInputEvent(result[1], true, "insertCompositionText", "", [],
+                  "runCompositionCommitTest: when replacing with empty string with composition");
+  is(result[2].type, "compositionend",
+     "runCompositionCommitTest: compositionend should be fired when replacing with empty string with composition");
+  is(result[3].type, "input",
+     "runCompositionCommitTest: input should be fired when replacing with empty string with composition");
+  checkInputEvent(result[3], false, "insertCompositionText", "", [],
+                  "runCompositionCommitTest: when replacing with empty string with composition");
+  is(textarea.value, "",
+     "runCompositionCommitTest: textarea should become empty when replacing selection with empty string with composition");
+
+  // replacing selection with same string with simple composition.
+  textarea.value = "abc";
+  textarea.setSelectionRange(0, 3);
+  synthesizeComposition({ type: "compositionstart" });
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommit", data: "abc" });
+
+  is(result.length, 5,
+     "runCompositionCommitTest: 5 events should be fired when replacing selection with same string with composition");
+  is(result[0].type, "compositionupdate",
+     "runCompositionCommitTest: compositionupdate should be fired when replacing selection with same string with composition");
+  is(result[1].type, "text",
+     "runCompositionCommitTest: text should be fired when replacing selection with same string with composition");
+  is(result[2].type, "beforeinput",
+     "runCompositionCommitTest: beforeinput should be fired when replacing selection with same string with composition");
+  checkInputEvent(result[2], true, "insertCompositionText", "abc", [],
+                  "runCompositionCommitTest: when replacing selection with same string with composition");
+  is(result[3].type, "compositionend",
+     "runCompositionCommitTest: compositionend should be fired when replacing selection with same string with composition");
+  is(result[4].type, "input",
+     "runCompositionCommitTest: input should be fired when replacing selection with same string with composition");
+  checkInputEvent(result[4], false, "insertCompositionText", "abc", [],
+                  "runCompositionCommitTest: when replacing selection with same string with composition");
+  is(textarea.value, "abc",
+     "runCompositionCommitTest: textarea should keep same value when replacing selection with same string with composition");
+
+  // compositioncommit with non-empty composition string.
+  textarea.value = "";
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "a" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitTest: textarea doesn't have composition string #4");
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommit", data: "", key: { key: "KEY_Enter" } });
+
+  is(result.length, 5,
+     "runCompositionCommitTest: 5 events should be fired after dispatching compositioncommit #4");
+  is(result[0].type, "compositionupdate",
+     "runCompositionCommitTest: compositionupdate should be fired after dispatching compositioncommit #4");
+  is(result[1].type, "text",
+     "runCompositionCommitTest: text should be fired after dispatching compositioncommit #4");
+  is(result[2].type, "beforeinput",
+     "runCompositionCommitTest: beforeinput should be fired after dispatching compositioncommit #4");
+  checkInputEvent(result[2], true, "insertCompositionText", "", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #4");
+  is(result[3].type, "compositionend",
+     "runCompositionCommitTest: compositionend should be fired after dispatching compositioncommit #4");
+  is(result[4].type, "input",
+     "runCompositionCommitTest: input should be fired after dispatching compositioncommit #4");
+  checkInputEvent(result[4], false, "insertCompositionText", "", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #4");
+  is(textarea.value, "", "runCompositionCommitTest: textarea should be empty #4");
+
+  // compositioncommit immediately without compositionstart
+  textarea.value = "";
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommit", data: "\u3042", key: { key: "a" } });
+
+  is(result.length, 5,
+     "runCompositionCommitTest: 5 events should be fired after dispatching compositioncommit #5");
+  is(result[0].type, "compositionupdate",
+     "runCompositionCommitTest: compositionupdate should be fired after dispatching compositioncommit #5");
+  is(result[1].type, "text",
+     "runCompositionCommitTest: text should be fired after dispatching compositioncommit #5");
+  is(result[2].type, "beforeinput",
+     "runCompositionCommitTest: beforeinput should be fired after dispatching compositioncommit #5");
+  checkInputEvent(result[2], true, "insertCompositionText", "\u3042", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #5");
+  is(result[3].type, "compositionend",
+     "runCompositionCommitTest: compositionend should be fired after dispatching compositioncommit #5");
+  is(result[4].type, "input",
+     "runCompositionCommitTest: input should be fired after dispatching compositioncommit #5");
+  checkInputEvent(result[4], false, "insertCompositionText", "\u3042", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #5");
+  is(textarea.value, "\u3042", "runCompositionCommitTest: textarea should be empty #5");
+
+  // compositioncommit with same composition string.
+  textarea.value = "";
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "a" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitTest: textarea doesn't have composition string #5");
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommit", data: "\u3042", key: { key: "KEY_Enter" } });
+
+  is(result.length, 4,
+     "runCompositionCommitTest: 4 events should be fired after dispatching compositioncommit #6");
+  is(result[0].type, "text",
+     "runCompositionCommitTest: text should be fired after dispatching compositioncommit #6");
+  is(result[1].type, "beforeinput",
+     "runCompositionCommitTest: beforeinput should be fired after dispatching compositioncommit #6");
+  checkInputEvent(result[1], true, "insertCompositionText", "\u3042", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #6");
+  is(result[2].type, "compositionend",
+     "runCompositionCommitTest: compositionend should be fired after dispatching compositioncommit #6");
+  is(result[3].type, "input",
+     "runCompositionCommitTest: input should be fired after dispatching compositioncommit #6");
+  checkInputEvent(result[3], false, "insertCompositionText", "\u3042", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #6");
+  is(textarea.value, "\u3042", "runCompositionCommitTest: textarea should have committed string #6");
+
+  // compositioncommit with same composition string when there is committed string
+  textarea.value = "";
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "a" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitTest: textarea doesn't have composition string #6");
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "KEY_Enter", type: "keydown" },
+    });
+  is(textarea.value, "\u3042", "runCompositionCommitTest: textarea doesn't have composition string #6");
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommit", data: "\u3042", key: { key: "KEY_Enter", type: "keyup" } });
+
+  is(result.length, 2,
+     "runCompositionCommitTest: 2 events should be fired after dispatching compositioncommit #7");
+  // XXX Do we need a "beforeinput" event here? Not sure.
+  is(result[0].type, "compositionend",
+     "runCompositionCommitTest: compositionend should be fired after dispatching compositioncommit #7");
+  is(result[1].type, "input",
+     "runCompositionCommitTest: input should be fired after dispatching compositioncommit #7");
+  checkInputEvent(result[1], false, "insertCompositionText", "\u3042", [],
+                  "runCompositionCommitTest: after dispatching compositioncommit #7");
+  is(textarea.value, "\u3042", "runCompositionCommitTest: textarea should have committed string #6");
+
+  textarea.removeEventListener("compositionupdate", handler, true);
+  textarea.removeEventListener("compositionend", handler, true);
+  textarea.removeEventListener("beforeinput", handler, true);
+  textarea.removeEventListener("input", handler, true);
+  textarea.removeEventListener("text", handler, true);
+}
+
+// eslint-disable-next-line complexity
+async function runCompositionTest()
+{
+  textarea.value = "";
+  textarea.focus();
+  let caretRects = [];
+
+  let caretRect = synthesizeQueryCaretRect(0);
+  if (!checkQueryContentResult(caretRect,
+        "runCompositionTest: synthesizeQueryCaretRect #0")) {
+    return;
+  }
+  caretRects[0] = caretRect;
+
+  // input first character
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "o" },
+    });
+
+  if (!checkContent("\u3089", "runCompositionTest", "#1-1") ||
+      !checkSelection(1, "", "runCompositionTest", "#1-1")) {
+    return;
+  }
+
+  caretRect = synthesizeQueryCaretRect(1);
+  if (!checkQueryContentResult(caretRect,
+        "runCompositionTest: synthesizeQueryCaretRect #1-1")) {
+    return;
+  }
+  caretRects[1] = caretRect;
+
+  // input second character
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 },
+      "key": { key: "\\", code: "IntlYen", keyCode: KeyboardEvent.DOM_VK_BACKSLASH },
+    });
+
+  if (!checkContent("\u3089\u30FC", "runCompositionTest", "#1-2") ||
+      !checkSelection(2, "", "runCompositionTest", "#1-2")) {
+    return;
+  }
+
+  caretRect = synthesizeQueryCaretRect(2);
+  if (!checkQueryContentResult(caretRect,
+        "runCompositionTest: synthesizeQueryCaretRect #1-2")) {
+    return;
+  }
+  caretRects[2] = caretRect;
+
+  isnot(caretRects[2].left, caretRects[1].left,
+        "runCompositionTest: caret isn't moved (#1-2)");
+  is(caretRects[2].top, caretRects[1].top,
+     "runCompositionTest: caret is moved to another line (#1-2)");
+  is(caretRects[2].width, caretRects[1].width,
+     "runCompositionTest: caret width is wrong (#1-2)");
+  is(caretRects[2].height, caretRects[1].height,
+     "runCompositionTest: caret width is wrong (#1-2)");
+
+  // input third character
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081",
+        "clauses":
+        [
+          { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 3, "length": 0 },
+      "key": { key: "/" },
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081", "runCompositionTest", "#1-3") ||
+      !checkSelection(3, "", "runCompositionTest", "#1-3")) {
+    return;
+  }
+
+  caretRect = synthesizeQueryCaretRect(3);
+  if (!checkQueryContentResult(caretRect,
+        "runCompositionTest: synthesizeQueryCaretRect #1-3")) {
+    return;
+  }
+  caretRects[3] = caretRect;
+
+  isnot(caretRects[3].left, caretRects[2].left,
+        "runCompositionTest: caret isn't moved (#1-3)");
+  is(caretRects[3].top, caretRects[2].top,
+     "runCompositionTest: caret is moved to another line (#1-3)");
+  is(caretRects[3].width, caretRects[2].width,
+     "runCompositionTest: caret width is wrong (#1-3)");
+  is(caretRects[3].height, caretRects[2].height,
+     "runCompositionTest: caret height is wrong (#1-3)");
+
+  // moves the caret left
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081",
+        "clauses":
+        [
+          { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 },
+      "key": { key: "KEY_ArrowLeft" },
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081", "runCompositionTest", "#1-3-1") ||
+      !checkSelection(2, "", "runCompositionTest", "#1-3-1")) {
+    return;
+  }
+
+
+  caretRect = synthesizeQueryCaretRect(2);
+  if (!checkQueryContentResult(caretRect,
+        "runCompositionTest: synthesizeQueryCaretRect #1-3-1")) {
+    return;
+  }
+
+  is(caretRect.left, caretRects[2].left,
+     "runCompositionTest: caret rects are different (#1-3-1, left)");
+  is(caretRect.top, caretRects[2].top,
+     "runCompositionTest: caret rects are different (#1-3-1, top)");
+  // by bug 335359, the caret width depends on the right side's character.
+  is(caretRect.width, caretRects[2].width + Math.round(window.devicePixelRatio),
+     "runCompositionTest: caret rects are different (#1-3-1, width)");
+  is(caretRect.height, caretRects[2].height,
+     "runCompositionTest: caret rects are different (#1-3-1, height)");
+
+  // moves the caret left
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081",
+        "clauses":
+        [
+          { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "KEY_ArrowLeft" },
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081", "runCompositionTest", "#1-3-2") ||
+      !checkSelection(1, "", "runCompositionTest", "#1-3-2")) {
+    return;
+  }
+
+
+  caretRect = synthesizeQueryCaretRect(1);
+  if (!checkQueryContentResult(caretRect,
+        "runCompositionTest: synthesizeQueryCaretRect #1-3-2")) {
+    return;
+  }
+
+  is(caretRect.left, caretRects[1].left,
+     "runCompositionTest: caret rects are different (#1-3-2, left)");
+  is(caretRect.top, caretRects[1].top,
+     "runCompositionTest: caret rects are different (#1-3-2, top)");
+  // by bug 335359, the caret width depends on the right side's character.
+  is(caretRect.width, caretRects[1].width + Math.round(window.devicePixelRatio),
+     "runCompositionTest: caret rects are different (#1-3-2, width)");
+  is(caretRect.height, caretRects[1].height,
+     "runCompositionTest: caret rects are different (#1-3-2, height)");
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093",
+        "clauses":
+        [
+          { "length": 4, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 4, "length": 0 },
+      "key": { key: "y" },
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093", "runCompositionTest", "#1-4") ||
+      !checkSelection(4, "", "runCompositionTest", "#1-4")) {
+    return;
+  }
+
+
+  // backspace
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081",
+        "clauses":
+        [
+          { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 3, "length": 0 },
+      "key": { key: "KEY_Backspace" },
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081", "runCompositionTest", "#1-5") ||
+      !checkSelection(3, "", "runCompositionTest", "#1-5")) {
+    return;
+  }
+
+  // re-input
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093",
+        "clauses":
+        [
+          { "length": 4, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 4, "length": 0 },
+      "key": { key: "y" },
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093", "runCompositionTest", "#1-6") ||
+      !checkSelection(4, "", "runCompositionTest", "#1-6")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093\u3055",
+        "clauses":
+        [
+          { "length": 5, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 5, "length": 0 },
+      "key": { key: "x" },
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093\u3055", "runCompositionTest", "#1-7") ||
+      !checkSelection(5, "", "runCompositionTest", "#1-7")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093\u3055\u3044",
+        "clauses":
+        [
+          { "length": 6, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 6, "length": 0 },
+      "key": { key: "e" },
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093\u3055\u3044", "runCompositionTest", "#1-8") ||
+      !checkSelection(6, "", "runCompositionTest", "#1-8")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093\u3055\u3044\u3053",
+        "clauses":
+        [
+          { "length": 7, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 7, "length": 0 },
+      "key": { key: "b" },
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093\u3055\u3044\u3053", "runCompositionTest", "#1-8") ||
+      !checkSelection(7, "", "runCompositionTest", "#1-8")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093\u3055\u3044\u3053\u3046",
+        "clauses":
+        [
+          { "length": 8, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 8, "length": 0 },
+      "key": { key: "4" },
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093\u3055\u3044\u3053\u3046",
+                    "runCompositionTest", "#1-9") ||
+      !checkSelection(8, "", "runCompositionTest", "#1-9")) {
+    return;
+  }
+
+  // convert
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u30E9\u30FC\u30E1\u30F3\u6700\u9AD8",
+        "clauses":
+        [
+          { "length": 4,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+          { "length": 2,
+            "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 4, "length": 0 },
+      "key": { key: " " },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u6700\u9AD8",
+                    "runCompositionTest", "#1-10") ||
+      !checkSelection(4, "", "runCompositionTest", "#1-10")) {
+    return;
+  }
+
+  // change the selected clause
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u30E9\u30FC\u30E1\u30F3\u6700\u9AD8",
+        "clauses":
+        [
+          { "length": 4,
+            "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE },
+          { "length": 2,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 6, "length": 0 },
+      "key": { key: "KEY_ArrowLeft", shiftKey: true },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u6700\u9AD8",
+                    "runCompositionTest", "#1-11") ||
+      !checkSelection(6, "", "runCompositionTest", "#1-11")) {
+    return;
+  }
+
+  // reset clauses
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u30E9\u30FC\u30E1\u30F3\u3055\u884C\u3053\u3046",
+        "clauses":
+        [
+          { "length": 5,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+          { "length": 3,
+            "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 5, "length": 0 },
+      "key": { key: "KEY_ArrowRight" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u3055\u884C\u3053\u3046",
+                    "runCompositionTest", "#1-12") ||
+      !checkSelection(5, "", "runCompositionTest", "#1-12")) {
+    return;
+  }
+
+
+  let textRect1 = synthesizeQueryTextRect(0, 1);
+  let textRect2 = synthesizeQueryTextRect(1, 1);
+  if (!checkQueryContentResult(textRect1,
+        "runCompositionTest: synthesizeQueryTextRect #1-12-1") ||
+      !checkQueryContentResult(textRect2,
+        "runCompositionTest: synthesizeQueryTextRect #1-12-2")) {
+    return;
+  }
+
+  // commit the composition string
+  synthesizeComposition({ type: "compositioncommitasis" });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u3055\u884C\u3053\u3046",
+                    "runCompositionTest", "#1-13") ||
+      !checkSelection(8, "", "runCompositionTest", "#1-13")) {
+    return;
+  }
+
+  let textRect3 = synthesizeQueryTextRect(0, 1);
+  let textRect4 = synthesizeQueryTextRect(1, 1);
+
+  if (!checkQueryContentResult(textRect3,
+        "runCompositionTest: synthesizeQueryTextRect #1-13-1") ||
+      !checkQueryContentResult(textRect4,
+        "runCompositionTest: synthesizeQueryTextRect #1-13-2")) {
+    return;
+  }
+
+  checkRect(textRect3, textRect1, "runCompositionTest: textRect #1-13-1");
+  checkRect(textRect4, textRect2, "runCompositionTest: textRect #1-13-2");
+
+  // restart composition and input characters
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3057",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "d" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u3055\u884C\u3053\u3046\u3057",
+                    "runCompositionTest", "#2-1") ||
+      !checkSelection(8 + 1, "", "runCompositionTest", "#2-1")) {
+    return;
+  }
+
+  let textRect3QueriedWithRelativeOffset = synthesizeQueryTextRect(-8, 1, true);
+  let textRect4QueriedWithRelativeOffset = synthesizeQueryTextRect(-8 + 1, 1, true);
+  checkRect(textRect3QueriedWithRelativeOffset, textRect3, "runCompositionTest: textRect #2-1-2");
+  checkRect(textRect4QueriedWithRelativeOffset, textRect4, "runCompositionTest: textRect #2-1-3");
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3058",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "r" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u3055\u884C\u3053\u3046\u3058",
+                    "runCompositionTest", "#2-2") ||
+      !checkSelection(8 + 1, "", "runCompositionTest", "#2-2")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3058\u3087",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 },
+      "key": { key: ")", code: "Digit9", keyCode: KeyboardEvent.DOM_VK_9, shiftKey: true },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u3055\u884C\u3053\u3046\u3058\u3087",
+                    "runCompositionTest", "#2-3") ||
+      !checkSelection(8 + 2, "", "runCompositionTest", "#2-3")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3058\u3087\u3046",
+        "clauses":
+        [
+          { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 3, "length": 0 },
+      "key": { key: "4" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u3055\u884C\u3053\u3046\u3058\u3087\u3046",
+                    "runCompositionTest", "#2-4") ||
+      !checkSelection(8 + 3, "", "runCompositionTest", "#2-4")) {
+    return;
+  }
+
+  // commit the composition string
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u3055\u884C\u3053\u3046\u3058\u3087\u3046",
+                    "runCompositionTest", "#2-4") ||
+      !checkSelection(8 + 3, "", "runCompositionTest", "#2-4")) {
+    return;
+  }
+
+  // set selection
+  const selectionSetTest = await synthesizeSelectionSet(4, 7, false);
+  ok(selectionSetTest, "runCompositionTest: selectionSetTest failed");
+
+  if (!checkSelection(4, "\u3055\u884C\u3053\u3046\u3058\u3087\u3046", "runCompositionTest", "#3-1")) {
+    return;
+  }
+
+  // start composition with selection
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u304A",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "6" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u304A",
+                    "runCompositionTest", "#3-2") ||
+      !checkSelection(4 + 1, "", "runCompositionTest", "#3-2")) {
+    return;
+  }
+
+  // remove the composition string
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+      "caret": { "start": 0, "length": 0 },
+      "key": { key: "KEY_Backspace" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3",
+                    "runCompositionTest", "#3-3") ||
+      !checkSelection(4, "", "runCompositionTest", "#3-3")) {
+    return;
+  }
+
+  // re-input the composition string
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3046",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "4" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u3046",
+                    "runCompositionTest", "#3-4") ||
+      !checkSelection(4 + 1, "", "runCompositionTest", "#3-4")) {
+    return;
+  }
+
+  // cancel the composition
+  synthesizeComposition({ type: "compositioncommit", data: "", key: { key: "KEY_Escape" } });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3",
+                    "runCompositionTest", "#3-5") ||
+      !checkSelection(4, "", "runCompositionTest", "#3-5")) {
+    return;
+  }
+
+  // bug 271815, some Chinese IMEs for Linux make empty composition string
+  // and compty clause information when it lists up Chinese characters on
+  // its candidate window.
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+      "caret": { "start": 0, "length": 0 },
+      "key": { key: "a" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3",
+                    "runCompositionTest", "#4-1") ||
+      !checkSelection(4, "", "runCompositionTest", "#4-1")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+      "caret": { "start": 0, "length": 0 },
+      "key": { key: "b" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3",
+                    "runCompositionTest", "#4-2") ||
+      !checkSelection(4, "", "runCompositionTest", "#4-2")) {
+    return;
+  }
+
+  synthesizeComposition({ type: "compositioncommit", data: "\u6700", key: { key: "KEY_Enter" } });
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u6700",
+                    "runCompositionTest", "#4-3") ||
+      !checkSelection(5, "", "runCompositionTest", "#4-3")) {
+    return;
+  }
+
+  // testing the canceling case
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+      "caret": { "start": 0, "length": 0 },
+      "key": { key: "a" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u6700",
+                    "runCompositionTest", "#4-5") ||
+      !checkSelection(5, "", "runCompositionTest", "#4-5")) {
+    return;
+  }
+
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Escape" } });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u6700",
+                    "runCompositionTest", "#4-6") ||
+      !checkSelection(5, "", "runCompositionTest", "#4-6")) {
+    return;
+  }
+
+  // testing whether the empty composition string deletes selected string.
+  synthesizeKey("KEY_ArrowLeft", {shiftKey: true});
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+      "caret": { "start": 0, "length": 0 },
+      "key": { key: "a" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3",
+                    "runCompositionTest", "#4-8") ||
+      !checkSelection(4, "", "runCompositionTest", "#4-8")) {
+    return;
+  }
+
+  synthesizeComposition({ type: "compositioncommit", data: "\u9AD8", key: { key: "KEY_Enter" } });
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u9AD8",
+                    "runCompositionTest", "#4-9") ||
+      !checkSelection(5, "", "runCompositionTest", "#4-9")) {
+    return;
+  }
+
+  synthesizeKey("KEY_Backspace");
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3",
+                    "runCompositionTest", "#4-11") ||
+      !checkSelection(4, "", "runCompositionTest", "#4-11")) {
+    return;
+  }
+
+  // bug 23558, ancient Japanese IMEs on Window may send empty text event
+  // twice at canceling composition.
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u6700",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "a" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u6700",
+                    "runCompositionTest", "#5-1") ||
+      !checkSelection(4 + 1, "", "runCompositionTest", "#5-1")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+      "caret": { "start": 0, "length": 0 },
+      "key": { key: "KEY_Backspace", type: "keydown" },
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3",
+                    "runCompositionTest", "#5-2") ||
+      !checkSelection(4, "", "runCompositionTest", "#5-2")) {
+    return;
+  }
+
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Backspace", type: "keyup" } });
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3",
+                    "runCompositionTest", "#5-3") ||
+      !checkSelection(4, "", "runCompositionTest", "#5-3")) {
+    return;
+  }
+
+  // Undo tests for the testcases for bug 23558 and bug 271815
+  synthesizeKey("z", { accelKey: true });
+
+  // XXX this is unexpected behavior, see bug 258291
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3",
+                    "runCompositionTest", "#6-1") ||
+      !checkSelection(4, "", "runCompositionTest", "#6-1")) {
+    return;
+  }
+
+  synthesizeKey("z", { accelKey: true });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u9AD8",
+                    "runCompositionTest", "#6-2") ||
+      !checkSelection(5, "", "runCompositionTest", "#6-2")) {
+    return;
+  }
+
+  synthesizeKey("z", { accelKey: true });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u6700",
+                    "runCompositionTest", "#6-3") ||
+      !checkSelection(4, "", "runCompositionTest", "#6-3")) {
+    return;
+  }
+
+  synthesizeKey("z", { accelKey: true });
+
+  // XXX this is unexpected behavior, see bug 258291
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u6700",
+                    "runCompositionTest", "#6-4") ||
+      !checkSelection(5, "", "runCompositionTest", "#6-4")) {
+    return;
+  }
+
+  synthesizeKey("z", { accelKey: true });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3",
+                    "runCompositionTest", "#6-5") ||
+      !checkSelection(4, "", "runCompositionTest", "#6-5")) {
+    // eslint-disable-next-line no-useless-return
+    return;
+  }
+}
+
+function runCompositionEventTest()
+{
+  const kDescription = "runCompositionEventTest: ";
+  const kEvents = ["compositionstart", "compositionupdate", "compositionend",
+                   "input"];
+
+  input.value = "";
+  input.focus();
+
+  let windowEventCounts = [], windowEventData = [], windowEventLocale = [];
+  let inputEventCounts = [], inputEventData = [], inputEventLocale = [];
+  let preventDefault = false;
+  let stopPropagation = false;
+
+  function initResults()
+  {
+    for (let i = 0; i < kEvents.length; i++) {
+      windowEventCounts[kEvents[i]] = 0;
+      windowEventData[kEvents[i]] = "";
+      windowEventLocale[kEvents[i]] = "";
+      inputEventCounts[kEvents[i]] = 0;
+      inputEventData[kEvents[i]] = "";
+      inputEventLocale[kEvents[i]] = "";
+    }
+  }
+
+  function compositionEventHandlerForWindow(aEvent)
+  {
+    windowEventCounts[aEvent.type]++;
+    windowEventData[aEvent.type] = aEvent.data;
+    windowEventLocale[aEvent.type] = aEvent.locale;
+    if (preventDefault) {
+      aEvent.preventDefault();
+    }
+    if (stopPropagation) {
+      aEvent.stopPropagation();
+    }
+  }
+
+  function formEventHandlerForWindow(aEvent)
+  {
+    ok(aEvent.isTrusted, "input events must be trusted events");
+    windowEventCounts[aEvent.type]++;
+    windowEventData[aEvent.type] = input.value;
+  }
+
+  function compositionEventHandlerForInput(aEvent)
+  {
+    inputEventCounts[aEvent.type]++;
+    inputEventData[aEvent.type] = aEvent.data;
+    inputEventLocale[aEvent.type] = aEvent.locale;
+    if (preventDefault) {
+      aEvent.preventDefault();
+    }
+    if (stopPropagation) {
+      aEvent.stopPropagation();
+    }
+  }
+
+  function formEventHandlerForInput(aEvent)
+  {
+    inputEventCounts[aEvent.type]++;
+    inputEventData[aEvent.type] = input.value;
+  }
+
+  window.addEventListener("compositionstart", compositionEventHandlerForWindow,
+                          true, true);
+  window.addEventListener("compositionend", compositionEventHandlerForWindow,
+                          true, true);
+  window.addEventListener("compositionupdate", compositionEventHandlerForWindow,
+                          true, true);
+  window.addEventListener("input", formEventHandlerForWindow,
+                          true, true);
+
+  input.addEventListener("compositionstart", compositionEventHandlerForInput,
+                         true, true);
+  input.addEventListener("compositionend", compositionEventHandlerForInput,
+                         true, true);
+  input.addEventListener("compositionupdate", compositionEventHandlerForInput,
+                         true, true);
+  input.addEventListener("input", formEventHandlerForInput,
+                         true, true);
+
+  // test for normal case
+  initResults();
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "o" },
+    });
+
+  is(windowEventCounts.compositionstart, 1,
+     kDescription + "compositionstart hasn't been handled by window #1");
+  is(windowEventData.compositionstart, "",
+     kDescription + "data of compositionstart isn't empty (window) #1");
+  is(windowEventLocale.compositionstart, "",
+     kDescription + "locale of compositionstart isn't empty (window) #1");
+  is(inputEventCounts.compositionstart, 1,
+     kDescription + "compositionstart hasn't been handled by input #1");
+  is(inputEventData.compositionstart, "",
+     kDescription + "data of compositionstart isn't empty (input) #1");
+  is(inputEventLocale.compositionstart, "",
+     kDescription + "locale of compositionstart isn't empty (input) #1");
+
+  is(windowEventCounts.compositionupdate, 1,
+     kDescription + "compositionupdate hasn't been handled by window #1");
+  is(windowEventData.compositionupdate, "\u3089",
+     kDescription + "data of compositionupdate doesn't match (window) #1");
+  is(windowEventLocale.compositionupdate, "",
+     kDescription + "locale of compositionupdate isn't empty (window) #1");
+  is(inputEventCounts.compositionupdate, 1,
+     kDescription + "compositionupdate hasn't been handled by input #1");
+  is(inputEventData.compositionupdate, "\u3089",
+     kDescription + "data of compositionupdate doesn't match (input) #1");
+  is(inputEventLocale.compositionupdate, "",
+     kDescription + "locale of compositionupdate isn't empty (input) #1");
+
+  is(windowEventCounts.compositionend, 0,
+     kDescription + "compositionend has been handled by window #1");
+  is(inputEventCounts.compositionend, 0,
+     kDescription + "compositionend has been handled by input #1");
+
+  is(windowEventCounts.input, 1,
+     kDescription + "input hasn't been handled by window #1");
+  is(windowEventData.input, "\u3089",
+     kDescription + "value of input element wasn't modified (window) #1");
+  is(inputEventCounts.input, 1,
+     kDescription + "input hasn't been handled by input #1");
+  is(inputEventData.input, "\u3089",
+     kDescription + "value of input element wasn't modified (input) #1");
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 },
+      "key": { key: "\\", code: "IntlYen", keyCode: KeyboardEvent.DOM_VK_BACKSLASH },
+    });
+
+  is(windowEventCounts.compositionstart, 1,
+     kDescription + "compositionstart has been handled more than once by window #2");
+  is(inputEventCounts.compositionstart, 1,
+     kDescription + "compositionstart has been handled more than once by input #2");
+
+  is(windowEventCounts.compositionupdate, 2,
+     kDescription + "compositionupdate hasn't been handled by window #2");
+  is(windowEventData.compositionupdate, "\u3089\u30FC",
+     kDescription + "data of compositionupdate doesn't match (window) #2");
+  is(windowEventLocale.compositionupdate, "",
+     kDescription + "locale of compositionupdate isn't empty (window) #2");
+  is(inputEventCounts.compositionupdate, 2,
+     kDescription + "compositionupdate hasn't been handled by input #2");
+  is(inputEventData.compositionupdate, "\u3089\u30FC",
+     kDescription + "data of compositionupdate doesn't match (input) #2");
+  is(inputEventLocale.compositionupdate, "",
+     kDescription + "locale of compositionupdate isn't empty (input) #2");
+
+  is(windowEventCounts.compositionend, 0,
+     kDescription + "compositionend has been handled during composition by window #2");
+  is(inputEventCounts.compositionend, 0,
+     kDescription + "compositionend has been handled during composition by input #2");
+
+  is(windowEventCounts.input, 2,
+     kDescription + "input hasn't been handled by window #2");
+  is(windowEventData.input, "\u3089\u30FC",
+     kDescription + "value of input element wasn't modified (window) #2");
+  is(inputEventCounts.input, 2,
+     kDescription + "input hasn't been handled by input #2");
+  is(inputEventData.input, "\u3089\u30FC",
+     kDescription + "value of input element wasn't modified (input) #2");
+
+  // text event shouldn't cause composition update, e.g., at committing.
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  is(windowEventCounts.compositionstart, 1,
+     kDescription + "compositionstart has been handled more than once by window #3");
+  is(inputEventCounts.compositionstart, 1,
+     kDescription + "compositionstart has been handled more than once by input #3");
+
+  is(windowEventCounts.compositionupdate, 2,
+     kDescription + "compositionupdate has been fired unexpectedly on window #3");
+  is(inputEventCounts.compositionupdate, 2,
+     kDescription + "compositionupdate has been fired unexpectedly on input #3");
+
+  is(windowEventCounts.compositionend, 1,
+     kDescription + "compositionend hasn't been handled by window #3");
+  is(windowEventData.compositionend, "\u3089\u30FC",
+     kDescription + "data of compositionend doesn't match (window) #3");
+  is(windowEventLocale.compositionend, "",
+     kDescription + "locale of compositionend isn't empty (window) #3");
+  is(inputEventCounts.compositionend, 1,
+     kDescription + "compositionend hasn't been handled by input #3");
+  is(inputEventData.compositionend, "\u3089\u30FC",
+     kDescription + "data of compositionend doesn't match (input) #3");
+  is(inputEventLocale.compositionend, "",
+     kDescription + "locale of compositionend isn't empty (input) #3");
+
+  is(windowEventCounts.input, 3,
+     kDescription + "input hasn't been handled by window #3");
+  is(windowEventData.input, "\u3089\u30FC",
+     kDescription + "value of input element wasn't modified (window) #3");
+  is(inputEventCounts.input, 3,
+     kDescription + "input hasn't been handled by input #3");
+  is(inputEventData.input, "\u3089\u30FC",
+     kDescription + "value of input element wasn't modified (input) #3");
+
+  // select the second character, then, data of composition start should be
+  // the selected character.
+  initResults();
+  synthesizeKey("KEY_ArrowLeft", {shiftKey: true});
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "o" },
+    });
+
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  is(windowEventCounts.compositionstart, 1,
+     kDescription + "compositionstart hasn't been handled by window #4");
+  is(windowEventData.compositionstart, "\u30FC",
+     kDescription + "data of compositionstart is empty (window) #4");
+  is(windowEventLocale.compositionstart, "",
+     kDescription + "locale of compositionstart isn't empty (window) #4");
+  is(inputEventCounts.compositionstart, 1,
+     kDescription + "compositionstart hasn't been handled by input #4");
+  is(inputEventData.compositionstart, "\u30FC",
+     kDescription + "data of compositionstart is empty (input) #4");
+  is(inputEventLocale.compositionstart, "",
+     kDescription + "locale of compositionstart isn't empty (input) #4");
+
+  is(windowEventCounts.compositionupdate, 1,
+     kDescription + "compositionupdate hasn't been handled by window #4");
+  is(windowEventData.compositionupdate, "\u3089",
+     kDescription + "data of compositionupdate doesn't match (window) #4");
+  is(windowEventLocale.compositionupdate, "",
+     kDescription + "locale of compositionupdate isn't empty (window) #4");
+  is(inputEventCounts.compositionupdate, 1,
+     kDescription + "compositionupdate hasn't been handled by input #4");
+  is(inputEventData.compositionupdate, "\u3089",
+     kDescription + "data of compositionupdate doesn't match (input) #4");
+  is(inputEventLocale.compositionupdate, "",
+     kDescription + "locale of compositionupdate isn't empty (input) #4");
+
+  is(windowEventCounts.compositionend, 1,
+     kDescription + "compositionend hasn't been handled by window #4");
+  is(windowEventData.compositionend, "\u3089",
+     kDescription + "data of compositionend doesn't match (window) #4");
+  is(windowEventLocale.compositionend, "",
+     kDescription + "locale of compositionend isn't empty (window) #4");
+  is(inputEventCounts.compositionend, 1,
+     kDescription + "compositionend hasn't been handled by input #4");
+  is(inputEventData.compositionend, "\u3089",
+     kDescription + "data of compositionend doesn't match (input) #4");
+  is(inputEventLocale.compositionend, "",
+     kDescription + "locale of compositionend isn't empty (input) #4");
+
+  is(windowEventCounts.input, 2,
+     kDescription + "input hasn't been handled by window #4");
+  is(windowEventData.input, "\u3089\u3089",
+     kDescription + "value of input element wasn't modified (window) #4");
+  is(inputEventCounts.input, 2,
+     kDescription + "input hasn't been handled by input #4");
+  is(inputEventData.input, "\u3089\u3089",
+     kDescription + "value of input element wasn't modified (input) #4");
+
+  // preventDefault() should effect nothing.
+  preventDefault = true;
+
+  initResults();
+  synthesizeKey("a", { accelKey: true }); // Select All
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306D",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "," },
+    });
+
+  synthesizeComposition({ type: "compositioncommitasis" });
+
+  is(windowEventCounts.compositionstart, 1,
+     kDescription + "compositionstart hasn't been handled by window #5");
+  is(windowEventData.compositionstart, "\u3089\u3089",
+     kDescription + "data of compositionstart is empty (window) #5");
+  is(windowEventLocale.compositionstart, "",
+     kDescription + "locale of compositionstart isn't empty (window) #5");
+  is(inputEventCounts.compositionstart, 1,
+     kDescription + "compositionstart hasn't been handled by input #5");
+  is(inputEventData.compositionstart, "\u3089\u3089",
+     kDescription + "data of compositionstart is empty (input) #5");
+  is(inputEventLocale.compositionstart, "",
+     kDescription + "locale of compositionstart isn't empty (input) #5");
+
+  is(windowEventCounts.compositionupdate, 1,
+     kDescription + "compositionupdate hasn't been handled by window #5");
+  is(windowEventData.compositionupdate, "\u306D",
+     kDescription + "data of compositionupdate doesn't match (window) #5");
+  is(windowEventLocale.compositionupdate, "",
+     kDescription + "locale of compositionupdate isn't empty (window) #5");
+  is(inputEventCounts.compositionupdate, 1,
+     kDescription + "compositionupdate hasn't been handled by input #5");
+  is(inputEventData.compositionupdate, "\u306D",
+     kDescription + "data of compositionupdate doesn't match (input) #5");
+  is(inputEventLocale.compositionupdate, "",
+     kDescription + "locale of compositionupdate isn't empty (input) #5");
+
+  is(windowEventCounts.compositionend, 1,
+     kDescription + "compositionend hasn't been handled by window #5");
+  is(windowEventData.compositionend, "\u306D",
+     kDescription + "data of compositionend doesn't match (window) #5");
+  is(windowEventLocale.compositionend, "",
+     kDescription + "locale of compositionend isn't empty (window) #5");
+  is(inputEventCounts.compositionend, 1,
+     kDescription + "compositionend hasn't been handled by input #5");
+  is(inputEventData.compositionend, "\u306D",
+     kDescription + "data of compositionend doesn't match (input) #5");
+  is(inputEventLocale.compositionend, "",
+     kDescription + "locale of compositionend isn't empty (input) #5");
+
+  is(windowEventCounts.input, 2,
+     kDescription + "input hasn't been handled by window #5");
+  is(windowEventData.input, "\u306D",
+     kDescription + "value of input element wasn't modified (window) #5");
+  is(inputEventCounts.input, 2,
+     kDescription + "input hasn't been handled by input #5");
+  is(inputEventData.input, "\u306D",
+     kDescription + "value of input element wasn't modified (input) #5");
+
+  preventDefault = false;
+
+  // stopPropagation() should effect nothing (except event count)
+  stopPropagation = true;
+
+  initResults();
+  synthesizeKey("a", { accelKey: true }); // Select All
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "\\", code: "IntlRo", keyCode: KeyboardEvent.DOM_VK_BACKSLASH },
+    });
+
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  is(windowEventCounts.compositionstart, 1,
+     kDescription + "compositionstart hasn't been handled by window #6");
+  is(windowEventData.compositionstart, "\u306D",
+     kDescription + "data of compositionstart is empty #6");
+  is(windowEventLocale.compositionstart, "",
+     kDescription + "locale of compositionstart isn't empty #6");
+  is(inputEventCounts.compositionstart, 0,
+     kDescription + "compositionstart has been handled by input #6");
+
+  is(windowEventCounts.compositionupdate, 1,
+     kDescription + "compositionupdate hasn't been handled by window #6");
+  is(windowEventData.compositionupdate, "\u306E",
+     kDescription + "data of compositionupdate doesn't match #6");
+  is(windowEventLocale.compositionupdate, "",
+     kDescription + "locale of compositionupdate isn't empty #6");
+  is(inputEventCounts.compositionupdate, 0,
+     kDescription + "compositionupdate has been handled by input #6");
+
+  is(windowEventCounts.compositionend, 1,
+     kDescription + "compositionend hasn't been handled by window #6");
+  is(windowEventData.compositionend, "\u306E",
+     kDescription + "data of compositionend doesn't match #6");
+  is(windowEventLocale.compositionend, "",
+     kDescription + "locale of compositionend isn't empty #6");
+  is(inputEventCounts.compositionend, 0,
+     kDescription + "compositionend has been handled by input #6");
+
+  is(windowEventCounts.input, 2,
+     kDescription + "input hasn't been handled by window #6");
+  is(windowEventData.input, "\u306E",
+     kDescription + "value of input element wasn't modified (window) #6");
+  is(inputEventCounts.input, 2,
+     kDescription + "input hasn't been handled by input #6");
+  is(inputEventData.input, "\u306E",
+     kDescription + "value of input element wasn't modified (input) #6");
+
+  stopPropagation = false;
+
+  // create event and dispatch it.
+  initResults();
+
+  input.value = "value of input";
+  synthesizeKey("a", { accelKey: true }); // Select All
+
+  let compositionstart = document.createEvent("CompositionEvent");
+  compositionstart.initCompositionEvent("compositionstart",
+                                        true, true, document.defaultView,
+                                        "start data", "start locale");
+  is(compositionstart.type, "compositionstart",
+     kDescription + "type doesn't match #7");
+  is(compositionstart.data, "start data",
+     kDescription + "data doesn't match #7");
+  is(compositionstart.locale, "start locale",
+     kDescription + "locale doesn't match #7");
+  is(compositionstart.detail, 0,
+     kDescription + "detail isn't 0 #7");
+
+  input.dispatchEvent(compositionstart);
+
+  is(windowEventCounts.compositionstart, 1,
+     kDescription + "compositionstart hasn't been handled by window #7");
+  is(windowEventData.compositionstart, "start data",
+     kDescription + "data of compositionstart was changed (window) #7");
+  is(windowEventLocale.compositionstart, "start locale",
+     kDescription + "locale of compositionstart was changed (window) #7");
+  is(inputEventCounts.compositionstart, 1,
+     kDescription + "compositionstart hasn't been handled by input #7");
+  is(inputEventData.compositionstart, "start data",
+     kDescription + "data of compositionstart was changed (input) #7");
+  is(inputEventLocale.compositionstart, "start locale",
+     kDescription + "locale of compositionstart was changed (input) #7");
+
+  is(input.value, "value of input",
+     kDescription + "input value was changed #7");
+
+  let compositionupdate1 = document.createEvent("compositionevent");
+  compositionupdate1.initCompositionEvent("compositionupdate",
+                                          true, false, document.defaultView,
+                                          "composing string", "composing locale");
+  is(compositionupdate1.type, "compositionupdate",
+     kDescription + "type doesn't match #8");
+  is(compositionupdate1.data, "composing string",
+     kDescription + "data doesn't match #8");
+  is(compositionupdate1.locale, "composing locale",
+     kDescription + "locale doesn't match #8");
+  is(compositionupdate1.detail, 0,
+     kDescription + "detail isn't 0 #8");
+
+  input.dispatchEvent(compositionupdate1);
+
+  is(windowEventCounts.compositionupdate, 1,
+     kDescription + "compositionupdate hasn't been handled by window #8");
+  is(windowEventData.compositionupdate, "composing string",
+     kDescription + "data of compositionupdate was changed (window) #8");
+  is(windowEventLocale.compositionupdate, "composing locale",
+     kDescription + "locale of compositionupdate was changed (window) #8");
+  is(inputEventCounts.compositionupdate, 1,
+     kDescription + "compositionupdate hasn't been handled by input #8");
+  is(inputEventData.compositionupdate, "composing string",
+     kDescription + "data of compositionupdate was changed (input) #8");
+  is(inputEventLocale.compositionupdate, "composing locale",
+     kDescription + "locale of compositionupdate was changed (input) #8");
+
+  is(input.value, "value of input",
+     kDescription + "input value was changed #8");
+
+  let compositionupdate2 = document.createEvent("compositionEvent");
+  compositionupdate2.initCompositionEvent("compositionupdate",
+                                          true, false, document.defaultView,
+                                          "commit string", "commit locale");
+  is(compositionupdate2.type, "compositionupdate",
+     kDescription + "type doesn't match #9");
+  is(compositionupdate2.data, "commit string",
+     kDescription + "data doesn't match #9");
+  is(compositionupdate2.locale, "commit locale",
+     kDescription + "locale doesn't match #9");
+  is(compositionupdate2.detail, 0,
+     kDescription + "detail isn't 0 #9");
+
+  input.dispatchEvent(compositionupdate2);
+
+  is(windowEventCounts.compositionupdate, 2,
+     kDescription + "compositionupdate hasn't been handled by window #9");
+  is(windowEventData.compositionupdate, "commit string",
+     kDescription + "data of compositionupdate was changed (window) #9");
+  is(windowEventLocale.compositionupdate, "commit locale",
+     kDescription + "locale of compositionupdate was changed (window) #9");
+  is(inputEventCounts.compositionupdate, 2,
+     kDescription + "compositionupdate hasn't been handled by input #9");
+  is(inputEventData.compositionupdate, "commit string",
+     kDescription + "data of compositionupdate was changed (input) #9");
+  is(inputEventLocale.compositionupdate, "commit locale",
+     kDescription + "locale of compositionupdate was changed (input) #9");
+
+  is(input.value, "value of input",
+     kDescription + "input value was changed #9");
+
+  let compositionend = document.createEvent("Compositionevent");
+  compositionend.initCompositionEvent("compositionend",
+                                      true, false, document.defaultView,
+                                      "end data", "end locale");
+  is(compositionend.type, "compositionend",
+     kDescription + "type doesn't match #10");
+  is(compositionend.data, "end data",
+     kDescription + "data doesn't match #10");
+  is(compositionend.locale, "end locale",
+     kDescription + "locale doesn't match #10");
+  is(compositionend.detail, 0,
+     kDescription + "detail isn't 0 #10");
+
+  input.dispatchEvent(compositionend);
+
+  is(windowEventCounts.compositionend, 1,
+     kDescription + "compositionend hasn't been handled by window #10");
+  is(windowEventData.compositionend, "end data",
+     kDescription + "data of compositionend was changed (window) #10");
+  is(windowEventLocale.compositionend, "end locale",
+     kDescription + "locale of compositionend was changed (window) #10");
+  is(inputEventCounts.compositionend, 1,
+     kDescription + "compositionend hasn't been handled by input #10");
+  is(inputEventData.compositionend, "end data",
+     kDescription + "data of compositionend was changed (input) #10");
+  is(inputEventLocale.compositionend, "end locale",
+     kDescription + "locale of compositionend was changed (input) #10");
+
+  is(input.value, "value of input",
+     kDescription + "input value was changed #10");
+
+  window.removeEventListener("compositionstart",
+                             compositionEventHandlerForWindow, true);
+  window.removeEventListener("compositionend",
+                             compositionEventHandlerForWindow, true);
+  window.removeEventListener("compositionupdate",
+                             compositionEventHandlerForWindow, true);
+  window.removeEventListener("input",
+                             formEventHandlerForWindow, true);
+
+  input.removeEventListener("compositionstart",
+                            compositionEventHandlerForInput, true);
+  input.removeEventListener("compositionend",
+                            compositionEventHandlerForInput, true);
+  input.removeEventListener("compositionupdate",
+                            compositionEventHandlerForInput, true);
+  input.removeEventListener("input",
+                            formEventHandlerForInput, true);
+}
+
+function runCompositionTestWhoseTextNodeModified() {
+  const selection = windowOfContenteditable.getSelection();
+
+  (function testInsertTextBeforeComposition() {
+    const description =
+      "runCompositionTestWhoseTextNodeModified: testInsertTextBeforeComposition:";
+    contenteditable.focus();
+    contenteditable.innerHTML = "<p>def</p>";
+    const textNode = contenteditable.firstChild.firstChild;
+    selection.collapse(textNode, "def".length);
+    // Insert composition to the end of a text node
+    synthesizeSimpleCompositionChange("g");
+    is(
+      textNode.data,
+      "defg",
+      `${description} Composition should be inserted to end of the text node`
+    );
+
+    // Insert a character before the composition string
+    textNode.insertData(0, "c");
+    is(
+      textNode.data,
+      "cdefg",
+      `${
+        description
+      } Composition should be shifted when a character is inserted before it`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}cdef`.length,
+      "g",
+      `${
+        description
+      } IME selection should be shifted when a character is inserted before it`
+    );
+
+    // Update composition string (appending a character)
+    synthesizeSimpleCompositionChange("gh");
+    is(
+      textNode.data,
+      "cdefgh",
+      `${
+        description
+      } Composition should be updated correctly after inserted a character before it`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}cdef`.length,
+      "gh",
+      `${
+        description
+      } IME selection should be extended correctly at updating composition after inserted a character before it`
+    );
+
+    // Insert another character before the composition
+    textNode.insertData(0, "b");
+    is(
+      textNode.data,
+      "bcdefgh",
+      `${
+        description
+      } Composition should be shifted when a character is inserted again before it`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}bcdef`.length,
+      "gh",
+      `${
+        description
+      } IME selection should be shifted when a character is inserted again before it`
+    );
+
+    // Update the composition string again (appending another character)
+    synthesizeSimpleCompositionChange("ghi");
+    is(
+      textNode.data,
+      "bcdefghi",
+      `${
+        description
+      } Composition should be updated correctly after inserted 2 characters before it`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}bcdef`.length,
+      "ghi",
+      `${
+        description
+      } IME selection should be extended correctly at updating composition after inserted 2 characters before it`
+    );
+
+    // Insert a new character before the composition string
+    textNode.insertData(0, "a");
+    is(
+      textNode.data,
+      "abcdefghi",
+      `${
+        description
+      } Composition should be shifted when a character is inserted again and again before it`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}abcdef`.length,
+      "ghi",
+      `${
+        description
+      } IME selection should be shifted when a character is inserted again and again before it`
+    );
+
+    // Commit the composition string
+    synthesizeComposition({ type: "compositioncommitasis" });
+    is(
+      textNode.data,
+      "abcdefghi",
+      `${
+        description
+      } Composition should be committed as is`
+    );
+    is(
+      selection.focusOffset,
+      "abcdefghi".length,
+      `${description} Selection should be collapsed at end of the commit string`
+    );
+
+    // Undo the commit
+    synthesizeKey("z", { accelKey: true });
+    is(
+      textNode.data,
+      "abcdef",
+      `${
+        description
+      } Composition should be undone correctly`
+    );
+    is(
+      selection.focusOffset,
+      "abcdef".length,
+      `${
+        description
+      } Selection should be collapsed at where the composition was after undoing`
+    );
+
+    // Redo the commit
+    synthesizeKey("z", { accelKey: true, shiftKey: true });
+    is(
+      textNode.data,
+      "abcdefghi",
+      `${
+        description
+      } Composition should be redone correctly`
+    );
+    is(
+      selection.focusOffset,
+      "abcdefghi".length,
+      `${
+        description
+      } focus offset of Selection should be at end of the commit string after redoing`
+    );
+  })();
+
+  (function testInsertTextImmediatelyBeforeComposition() {
+    const description =
+      "runCompositionTestWhoseTextNodeModified: testInsertTextImmediatelyBeforeComposition:";
+    contenteditable.focus();
+    contenteditable.innerHTML = "<p>d</p>";
+    const textNode = contenteditable.firstChild.firstChild;
+    selection.collapse(textNode, 0);
+    // Insert composition at start of the text node
+    synthesizeSimpleCompositionChange("b");
+    is(
+      textNode.data,
+      "bd",
+      `${description} Composition should be inserted to start of the text node`
+    );
+
+    // Insert a character before the composition string
+    textNode.insertData(0, "a");
+    is(
+      textNode.data,
+      "abd",
+      `${
+        description
+      } Composition should be shifted when a character is inserted immediately before it`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}a`.length,
+      "b",
+      `${
+        description
+      } IME selection should be shifted when a character is inserted immediately before it`,
+      "",
+      { offset: todo_is, text: todo_is }
+    );
+
+    // Update the composition string after inserting character immediately before it
+    synthesizeSimpleCompositionChange("bc");
+    is(
+      textNode.data,
+      "abcd",
+      `${description} Composition should be updated after the inserted character`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}a`.length,
+      "bc",
+      `${
+        description
+      } IME selection should be set at the composition string after the inserted character`
+    );
+
+    // Commit it
+    synthesizeComposition({ type: "compositioncommitasis" });
+    is(
+      textNode.data,
+      "abcd",
+      `${
+        description
+      } Composition should be committed after the inserted character`
+    );
+    is(
+      selection.focusOffset,
+      "abc".length,
+      `${description} Selection should be collapsed at end of the commit string`
+    );
+  })();
+
+  (function testInsertTextImmediatelyAfterComposition() {
+    const description =
+      "runCompositionTestWhoseTextNodeModified: testInsertTextImmediatelyAfterComposition:";
+    contenteditable.focus();
+    contenteditable.innerHTML = "<p>a</p>";
+    const textNode = contenteditable.firstChild.firstChild;
+    selection.collapse(textNode, "a".length);
+    // Insert composition at end of the text node
+    synthesizeSimpleCompositionChange("b");
+    is(
+      textNode.data,
+      "ab",
+      `${description} Composition should be inserted to start of the text node`
+    );
+
+    // Insert a character after the composition string
+    textNode.insertData("ab".length, "d");
+    is(
+      textNode.data,
+      "abd",
+      `${
+        description
+      } Composition should stay when a character is inserted immediately after it`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}a`.length,
+      "b",
+      `${
+        description
+      } IME selection should stay when a character is inserted immediately after it`
+    );
+
+    // Update the composition string after inserting character immediately after it
+    synthesizeSimpleCompositionChange("bc");
+    is(
+      textNode.data,
+      "abcd",
+      `${description} Composition should be updated before the inserted character`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}a`.length,
+      "bc",
+      `${
+        description
+      } IME selection should be set at the composition string before the inserted character`
+    );
+
+    // Commit it
+    synthesizeComposition({ type: "compositioncommitasis" });
+    is(
+      textNode.data,
+      "abcd",
+      `${
+        description
+      } Composition should be committed before the inserted character`
+    );
+    is(
+      selection.focusOffset,
+      "abc".length,
+      `${description} Selection should be collapsed at end of the commit string`
+    );
+  })();
+
+  // Inserting/replacing text before the last character of composition string
+  // should be contained by the composition, i.e., updated by next composition
+  // update.  This is Chrome compatible.
+  (function testInsertTextMiddleOfComposition() {
+    const description =
+      "runCompositionTestWhoseTextNodeModified: testInsertTextMiddleOfComposition:";
+    contenteditable.focus();
+    contenteditable.innerHTML = "<p>a</p>";
+    const textNode = contenteditable.firstChild.firstChild;
+    selection.collapse(textNode, "a".length);
+    // Insert composition at middle of the text node
+    synthesizeSimpleCompositionChange("bd");
+    is(
+      textNode.data,
+      "abd",
+      `${description} Composition should be inserted to end of the text node`
+    );
+
+    // Insert a character before the composition string
+    textNode.insertData("ab".length, "c");
+    is(
+      textNode.data,
+      "abcd",
+      `${
+        description
+      } Inserted string should inserted into the middle of composition string`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}a`.length,
+      "bcd",
+      `${
+        description
+      } IME selection should be extended when a character is inserted into middle of it`
+    );
+
+    // Update the composition string after inserting character into it
+    synthesizeSimpleCompositionChange("BD");
+    is(
+      textNode.data,
+      "aBD",
+      `${
+        description
+      } Composition should be replace the range containing the inserted character`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}a`.length,
+      "BD",
+      `${
+        description
+      } IME selection should be set at the updated composition string`
+    );
+
+    // Commit it
+    synthesizeComposition({ type: "compositioncommitasis" });
+    is(
+      textNode.data,
+      "aBD",
+      `${
+        description
+      } Composition should be committed without the inserted character`
+    );
+    is(
+      selection.focusOffset,
+      "aBD".length,
+      `${description} Selection should be collapsed at end of the commit string`
+    );
+  })();
+
+  (function testReplaceFirstCharOfCompositionString() {
+    const description =
+      "runCompositionTestWhoseTextNodeModified: testReplaceFirstCharOfCompositionString:";
+    contenteditable.focus();
+    contenteditable.innerHTML = "<p>abfg</p>";
+    const textNode = contenteditable.firstChild.firstChild;
+    selection.collapse(textNode, "ab".length);
+    // Insert composition at middle of the text node
+    synthesizeSimpleCompositionChange("cde");
+    is(
+      textNode.data,
+      "abcdefg",
+      `${description} Composition should be inserted`
+    );
+
+    // Replace the composition string
+    textNode.replaceData("ab".length, "c".length, "XYZ");
+    is(
+      textNode.data,
+      "abXYZdefg",
+      `${description} First character of the composition should be replaced`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}ab`.length,
+      "XYZde",
+      `${description} IME selection should contain the replace string`
+    );
+
+    // Update the composition string after replaced
+    synthesizeSimpleCompositionChange("CDE");
+    is(
+      textNode.data,
+      "abCDEfg",
+      `${description} Composition should update the replace string too`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}ab`.length,
+      "CDE",
+      `${description} IME selection should update the replace string too`
+    );
+
+    // Commit it
+    synthesizeComposition({ type: "compositioncommitasis" });
+    is(
+      textNode.data,
+      "abCDEfg",
+      `${description} Composition should be committed`
+    );
+    is(
+      selection.focusOffset,
+      "abCDE".length,
+      `${description} Selection should be collapsed at end of the commit string`
+    );
+  })();
+
+  // Although Chrome commits composition if all composition string is removed,
+  // let's keep composition for making TSF stable...
+  (function testReplaceAllCompositionString() {
+    const description =
+      "runCompositionTestWhoseTextNodeModified: testReplaceAllCompositionString:";
+    contenteditable.focus();
+    contenteditable.innerHTML = "<p>abfg</p>";
+    const textNode = contenteditable.firstChild.firstChild;
+    selection.collapse(textNode, "ab".length);
+    // Insert composition at middle of the text node
+    synthesizeSimpleCompositionChange("cde");
+    is(
+      textNode.data,
+      "abcdefg",
+      `${description} Composition should be inserted to the text node`
+    );
+
+    // Replace the composition string
+    textNode.replaceData("ab".length, "cde".length, "XYZ");
+    is(
+      textNode.data,
+      "abXYZfg",
+      `${description} Composition should be replaced`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}ab`.length,
+      "",
+      `${
+        description
+      } IME selection should be collapsed before the replace string`
+    );
+
+    // Update the composition string after replaced
+    synthesizeSimpleCompositionChange("CDE");
+    is(
+      textNode.data,
+      "abCDEXYZfg",
+      `${description} Composition should be inserted again`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}ab`.length,
+      "CDE",
+      `${description} IME selection should not contain the replace string`
+    );
+
+    // Commit it
+    synthesizeComposition({ type: "compositioncommitasis" });
+    is(
+      textNode.data,
+      "abCDEXYZfg",
+      `${description} Composition should be committed`
+    );
+    is(
+      selection.focusOffset,
+      "abCDE".length,
+      `${description} Selection should be collapsed at end of the commit string`
+    );
+  })();
+
+  (function testReplaceCompositionStringAndSurroundedCharacters() {
+    const description =
+      "runCompositionTestWhoseTextNodeModified: testReplaceCompositionStringAndSurroundedCharacters:";
+    contenteditable.focus();
+    contenteditable.innerHTML = "<p>abfg</p>";
+    const textNode = contenteditable.firstChild.firstChild;
+    selection.collapse(textNode, "ab".length);
+    // Insert composition at middle of the text node
+    synthesizeSimpleCompositionChange("cde");
+    is(
+      textNode.data,
+      "abcdefg",
+      `${description} Composition should be inserted to the text node`
+    );
+
+    // Replace the composition string
+    textNode.replaceData("a".length, "bcdef".length, "XYZ");
+    is(
+      textNode.data,
+      "aXYZg",
+      `${description} Composition should be replaced`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}a`.length,
+      "",
+      `${
+        description
+      } IME selection should be collapsed before the replace string`
+    );
+
+    // Update the composition string after replaced
+    synthesizeSimpleCompositionChange("CDE");
+    is(
+      textNode.data,
+      "aCDEXYZg",
+      `${description} Composition should be inserted again`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}a`.length,
+      "CDE",
+      `${description} IME selection should not contain the replace string`
+    );
+
+    // Commit it
+    synthesizeComposition({ type: "compositioncommitasis" });
+    is(
+      textNode.data,
+      "aCDEXYZg",
+      `${description} Composition should be committed`
+    );
+    is(
+      selection.focusOffset,
+      "aCDE".length,
+      `${description} Selection should be collapsed at end of the commit string`
+    );
+  })();
+
+  // If start boundary characters are replaced, the replace string should be
+  // contained into the composition range.  This is Chrome compatible.
+  (function testReplaceStartBoundaryOfCompositionString() {
+    const description =
+      "runCompositionTestWhoseTextNodeModified: testReplaceStartBoundaryOfCompositionString:";
+    contenteditable.focus();
+    contenteditable.innerHTML = "<p>abfg</p>";
+    const textNode = contenteditable.firstChild.firstChild;
+    selection.collapse(textNode, "ab".length);
+    // Insert composition at middle of the text node
+    synthesizeSimpleCompositionChange("cde");
+    is(
+      textNode.data,
+      "abcdefg",
+      `${description} Composition should be inserted to the text node`
+    );
+
+    // Replace some text
+    textNode.replaceData("a".length, "bc".length, "XYZ");
+    is(
+      textNode.data,
+      "aXYZdefg",
+      `${
+        description
+      } Start of the composition should be replaced`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}a`.length,
+      "XYZde",
+      `${description} IME selection should contain the replace string`
+    );
+
+    // Update the replace string and remaining composition.
+    synthesizeSimpleCompositionChange("CDE");
+    is(
+      textNode.data,
+      "aCDEfg",
+      `${description} Composition should update the replace string too`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}a`.length,
+      "CDE",
+      `${description} IME selection should contain the replace string`
+    );
+
+    // Commit it
+    synthesizeComposition({ type: "compositioncommitasis" });
+    is(
+      textNode.data,
+      "aCDEfg",
+      `${
+        description
+      } Composition should be committed`
+    );
+    is(
+      selection.focusOffset,
+      "aCDE".length,
+      `${description} Selection should be collapsed at end of the commit string`
+    );
+  })();
+
+  // If start boundary characters are replaced, the replace string should NOT
+  // be contained in the composition range.  This is Chrome compatible.
+  (function testReplaceEndBoundaryOfCompositionString() {
+    const description =
+      "runCompositionTestWhoseTextNodeModified: testReplaceEndBoundaryOfCompositionString:";
+    contenteditable.focus();
+    contenteditable.innerHTML = "<p>abfg</p>";
+    const textNode = contenteditable.firstChild.firstChild;
+    selection.collapse(textNode, "ab".length);
+    // Insert composition at middle of the text node
+    synthesizeSimpleCompositionChange("cde");
+    is(
+      textNode.data,
+      "abcdefg",
+      `${description} Composition should be inserted to the text node`
+    );
+
+    // Replace the composition string
+    textNode.replaceData("abcd".length, "ef".length, "XYZ");
+    is(
+      textNode.data,
+      "abcdXYZg",
+      `${
+        description
+      } End half of the composition should be replaced`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}ab`.length,
+      "cd",
+      `${
+        description
+      } IME selection should be shrunken to the non-replaced part`
+    );
+
+    // Update the composition string after replaced
+    synthesizeSimpleCompositionChange("CDE");
+    is(
+      textNode.data,
+      "abCDEXYZg",
+      `${description} Only the remaining composition string should be updated`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}ab`.length,
+      "CDE",
+      `${description} IME selection should NOT include the replace string`
+    );
+
+    // Commit it
+    synthesizeComposition({ type: "compositioncommitasis" });
+    is(
+      textNode.data,
+      "abCDEXYZg",
+      `${description} Composition should be committed`
+    );
+    is(
+      selection.focusOffset,
+      "abCDE".length,
+      `${description} Selection should be collapsed at end of the commit string`
+    );
+  })();
+
+  // If the last character of composition is replaced, i.e., it should NOT be
+  // treated as a part of composition string.  This is Chrome compatible.
+  (function testReplaceLastCharOfCompositionString() {
+    const description =
+      "runCompositionTestWhoseTextNodeModified: testReplaceLastCharOfCompositionString:";
+    contenteditable.focus();
+    contenteditable.innerHTML = "<p>abfg</p>";
+    const textNode = contenteditable.firstChild.firstChild;
+    selection.collapse(textNode, "ab".length);
+    // Insert composition at middle of the text node
+    synthesizeSimpleCompositionChange("cde");
+    is(
+      textNode.data,
+      "abcdefg",
+      `${description} Composition should be inserted`
+    );
+
+    // Replace the composition string
+    textNode.replaceData("abcd".length, "e".length, "XYZ");
+    is(
+      textNode.data,
+      "abcdXYZfg",
+      `${description} Last character of the composition should be replaced`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}ab`.length,
+      "cd",
+      `${description} IME selection should be shrunken`
+    );
+
+    // Update the composition string after replaced
+    synthesizeSimpleCompositionChange("CDE");
+    is(
+      textNode.data,
+      "abCDEXYZfg",
+      `${description} Composition should NOT update the replace string`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}ab`.length,
+      "CDE",
+      `${description} IME selection should not contain the replace string`
+    );
+
+    // Commit it
+    synthesizeComposition({ type: "compositioncommitasis" });
+    is(
+      textNode.data,
+      "abCDEXYZfg",
+      `${description} Composition should be committed`
+    );
+    is(
+      selection.focusOffset,
+      "abCDE".length,
+      `${description} Selection should be collapsed at end of the commit string`
+    );
+  })();
+
+  (function testReplaceMiddleCharOfCompositionString() {
+    const description =
+      "runCompositionTestWhoseTextNodeModified: testReplaceMiddleCharOfCompositionString:";
+    contenteditable.focus();
+    contenteditable.innerHTML = "<p>abfg</p>";
+    const textNode = contenteditable.firstChild.firstChild;
+    selection.collapse(textNode, "ab".length);
+    // Insert composition at middle of the text node
+    synthesizeSimpleCompositionChange("cde");
+    is(
+      textNode.data,
+      "abcdefg",
+      `${description} Composition should be inserted`
+    );
+
+    // Replace the composition string
+    textNode.replaceData("abc".length, "d".length, "XYZ");
+    is(
+      textNode.data,
+      "abcXYZefg",
+      `${
+        description
+      } Middle character of the composition should be replaced`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}ab`.length,
+      "cXYZe",
+      `${description} IME selection should be extended by the replace string`
+    );
+
+    // Update the composition string after replaced
+    synthesizeSimpleCompositionChange("CDE");
+    is(
+      textNode.data,
+      "abCDEfg",
+      `${description} Composition should update the replace string`
+    );
+    checkIMESelection(
+      "RawClause",
+      true,
+      `${kLF}ab`.length,
+      "CDE",
+      `${description} IME selection should be shrunken after update`
+    );
+
+    // Commit it
+    synthesizeComposition({ type: "compositioncommitasis" });
+    is(
+      textNode.data,
+      "abCDEfg",
+      `${description} Composition should be committed`
+    );
+    is(
+      selection.focusOffset,
+      "abCDE".length,
+      `${description} Selection should be collapsed at end of the commit string`
+    );
+  })();
+}
+
+// eslint-disable-next-line complexity
+function runQueryTextRectInContentEditableTest()
+{
+  contenteditable.focus();
+
+  contenteditable.innerHTML = "<p>abc</p><p>def</p>";
+                      // \n    0  123    4  567
+                      // \r\n  01 234    56 789
+
+  let description = "runTextRectInContentEditableTest: \"" + contenteditable.innerHTML + "\", ";
+
+  // "a"
+  let a = synthesizeQueryTextRect(kLFLen, 1);
+  if (!checkQueryContentResult(a, description + "rect for 'a'")) {
+    return;
+  }
+
+  // "b"
+  let b = synthesizeQueryTextRect(kLFLen + 1, 1);
+  if (!checkQueryContentResult(b, description + "rect for 'b'")) {
+    return;
+  }
+
+  is(b.top, a.top, description + "'a' and 'b' should be at same top");
+  isSimilarTo(b.left, a.left + a.width, 2, description + "left of 'b' should be at similar to right of 'a'");
+  is(b.height, a.height, description + "'a' and 'b' should be same height");
+
+  // "c"
+  let c = synthesizeQueryTextRect(kLFLen + 2, 1);
+  if (!checkQueryContentResult(c, description + "rect for 'c'")) {
+    return;
+  }
+
+  is(c.top, b.top, description + "'b' and 'c' should be at same top");
+  isSimilarTo(c.left, b.left + b.width, 2, description + "left of 'c' should be at similar to right of 'b'");
+  is(c.height, b.height, description + "'b' and 'c' should be same height");
+
+  // "abc" as array
+  let abcAsArray = synthesizeQueryTextRectArray(kLFLen, 3);
+  if (!checkQueryContentResult(abcAsArray, description + "rect array for 'abc'") ||
+      !checkRectArray(abcAsArray, [a, b, c], description + "query text rect array result of 'abc' should match with each query text rect result")) {
+    return;
+  }
+
+  // 2nd <p> (can be computed with the rect of 'c')
+  let p2 = synthesizeQueryTextRect(kLFLen + 3, 1);
+  if (!checkQueryContentResult(p2, description + "rect for 2nd <p>")) {
+    return;
+  }
+
+  is(p2.top, c.top, description + "'c' and a line breaker caused by 2nd <p> should be at same top");
+  isSimilarTo(p2.left, c.left + c.width, 2, description + "left of a line breaker caused by 2nd <p> should be at similar to right of 'c'");
+  is(p2.height, c.height, description + "'c' and a line breaker caused by 2nd <p> should be same height");
+
+  // 2nd <p> as array
+  let p2AsArray = synthesizeQueryTextRectArray(kLFLen + 3, 1);
+  if (!checkQueryContentResult(p2AsArray, description + "2nd <p>'s line breaker as array") ||
+      !checkRectArray(p2AsArray, [p2], description + "query text rect array result of 2nd <p> should match with each query text rect result")) {
+    return;
+  }
+
+  if (kLFLen > 1) {
+    // \n of \r\n
+    let p2_2 = synthesizeQueryTextRect(kLFLen + 4, 1);
+    if (!checkQueryContentResult(p2_2, description + "rect for \\n of \\r\\n caused by 2nd <p>")) {
+      return;
+    }
+
+    is(p2_2.top, p2.top, description + "'\\r' and '\\n' should be at same top");
+    is(p2_2.left, p2.left, description + "'\\r' and '\\n' should be at same top");
+    is(p2_2.height, p2.height, description + "'\\r' and '\\n' should be same height");
+    is(p2_2.width, p2.width, description + "'\\r' and '\\n' should be same width");
+
+    // \n of \r\n as array
+    let p2_2AsArray = synthesizeQueryTextRectArray(kLFLen + 4, 1);
+    if (!checkQueryContentResult(p2_2AsArray, description + "rect array for \\n of \\r\\n caused by 2nd <p>") ||
+        !checkRectArray(p2_2AsArray, [p2_2], description + "query text rect array result of \\n of \\r\\n caused by 2nd <p> should match with each query text rect result")) {
+      return;
+    }
+  }
+
+  // "d"
+  let d = synthesizeQueryTextRect(kLFLen * 2 + 3, 1);
+  if (!checkQueryContentResult(d, description + "rect for 'd'")) {
+    return;
+  }
+
+  isGreaterThan(d.top, a.top + a.height, description + "top of 'd' should be greater than bottom of 'a'");
+  is(d.left, a.left, description + "'a' and 'd' should be same at same left");
+  is(d.height, a.height, description + "'a' and 'd' should be same height");
+
+  // "e"
+  let e = synthesizeQueryTextRect(kLFLen * 2 + 4, 1);
+  if (!checkQueryContentResult(e, description + "rect for 'e'")) {
+    return;
+  }
+
+  is(e.top, d.top, description + "'d' and 'd' should be at same top");
+  isSimilarTo(e.left, d.left + d.width, 2, description + "left of 'e' should be at similar to right of 'd'");
+  is(e.height, d.height, description + "'d' and 'e' should be same height");
+
+  // "f"
+  let f = synthesizeQueryTextRect(kLFLen * 2 + 5, 1);
+  if (!checkQueryContentResult(f, description + "rect for 'f'")) {
+    return;
+  }
+
+  is(f.top, e.top, description + "'e' and 'f' should be at same top");
+  isSimilarTo(f.left, e.left + e.width, 2, description + "left of 'f' should be at similar to right of 'e'");
+  is(f.height, e.height, description + "'e' and 'f' should be same height");
+
+  // "def" as array
+  let defAsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 3, 3);
+  if (!checkQueryContentResult(defAsArray, description + "rect array for 'def'") ||
+      !checkRectArray(defAsArray, [d, e, f], description + "query text rect array result of 'def' should match with each query text rect result")) {
+    return;
+  }
+
+  // next of "f" (can be computed with rect of 'f')
+  let next_f = synthesizeQueryTextRect(kLFLen * 2 + 6, 1);
+  if (!checkQueryContentResult(next_f, description + "rect for next of 'f'")) {
+    return;
+  }
+
+  is(next_f.top, d.top, 2, description + "'f' and next of 'f' should be at same top");
+  isSimilarTo(next_f.left, f.left + f.width, 2, description + "left of next of 'f' should be at similar to right of 'f'");
+  is(next_f.height, d.height, description + "'f' and next of 'f' should be same height");
+
+  // next of "f" as array
+  let next_fAsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 6, 1);
+  if (!checkQueryContentResult(next_fAsArray, description + "rect array for next of 'f'") ||
+      !checkRectArray(next_fAsArray, [next_f], description + "query text rect array result of next of 'f' should match with each query text rect result")) {
+    return;
+  }
+
+  // too big offset for the editor
+  let tooBigOffset = synthesizeQueryTextRect(kLFLen * 2 + 7, 1);
+  if (!checkQueryContentResult(tooBigOffset, description + "rect for too big offset")) {
+    return;
+  }
+
+  is(tooBigOffset.top, next_f.top, description + "too big offset and next of 'f' should be at same top");
+  is(tooBigOffset.left, next_f.left, description + "too big offset and next of 'f' should be at same left");
+  is(tooBigOffset.height, next_f.height, description + "too big offset and next of 'f' should be same height");
+  is(tooBigOffset.width, next_f.width, description + "too big offset and next of 'f' should be same width");
+
+  // too big offset for the editors as array
+  let tooBigOffsetAsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 7, 1);
+  if (!checkQueryContentResult(tooBigOffsetAsArray, description + "rect array for too big offset") ||
+      !checkRectArray(tooBigOffsetAsArray, [tooBigOffset], description + "query text rect array result with too big offset should match with each query text rect result")) {
+    return;
+  }
+
+  contenteditable.innerHTML = "<p>abc</p><p>def</p><p><br></p>";
+                      // \n    0  123    4  567    8  9
+                      // \r\n  01 234    56 789    01 23
+
+  description = "runTextRectInContentEditableTest: \"" + contenteditable.innerHTML + "\", ";
+
+  // "f"
+  f = synthesizeQueryTextRect(kLFLen * 2 + 5, 1);
+  if (!checkQueryContentResult(f, description + "rect for 'f'")) {
+    return;
+  }
+
+  is(f.top, e.top, description + "'e' and 'f' should be at same top");
+  is(f.height, e.height, description + "'e' and 'f' should be same height");
+  isSimilarTo(f.left, e.left + e.width, 2, description + "left of 'f' should be at similar to right of 'e'");
+
+  // 3rd <p> (can be computed with rect of 'f')
+  let p3 = synthesizeQueryTextRect(kLFLen * 2 + 6, 1);
+  if (!checkQueryContentResult(p3, description + "rect for 3rd <p>")) {
+    return;
+  }
+
+  is(p3.top, f.top, description + "'f' and a line breaker caused by 3rd <p> should be at same top");
+  is(p3.height, f.height, description + "'f' and a line breaker caused by 3rd <p> should be same height");
+  isSimilarTo(p3.left, f.left + f.width, 2, description + "left of a line breaker caused by 3rd <p> should be similar to right of 'f'");
+
+  // 3rd <p> as array
+  let p3AsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 6, 1);
+  if (!checkQueryContentResult(p3AsArray, description + "3rd <p>'s line breaker as array") ||
+      !checkRectArray(p3AsArray, [p3], description + "query text rect array result of 3rd <p> should match with each query text rect result")) {
+    return;
+  }
+
+  if (kLFLen > 1) {
+    // \n of \r\n
+    let p3_2 = synthesizeQueryTextRect(kLFLen * 2 + 7, 1);
+    if (!checkQueryContentResult(p3_2, description + "rect for \\n of \\r\\n caused by 3rd <p>")) {
+      return;
+    }
+
+    is(p3_2.top, p3.top, description + "'\\r' and '\\n' should be at same top");
+    is(p3_2.left, p3.left, description + "'\\r' and '\\n' should be at same top");
+    is(p3_2.height, p3.height, description + "'\\r' and '\\n' should be same height");
+    is(p3_2.width, p3.width, description + "'\\r' and '\\n' should be same width");
+
+    // \n of \r\n as array
+    let p3_2AsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 7, 1);
+    if (!checkQueryContentResult(p3_2AsArray, description + "rect array for \\n of \\r\\n caused by 3rd <p>") ||
+        !checkRectArray(p3_2AsArray, [p3_2], description + "query text rect array result of \\n of \\r\\n caused by 3rd <p> should match with each query text rect result")) {
+      return;
+    }
+  }
+
+  // <br> in 3rd <p>
+  let br = synthesizeQueryTextRect(kLFLen * 3 + 6, 1);
+  if (!checkQueryContentResult(br, description + "rect for <br> in 3rd <p>")) {
+    return;
+  }
+
+  isGreaterThan(br.top, d.top + d.height, description + "a line breaker caused by <br> in 3rd <p> should be greater than bottom of 'd'");
+  isSimilarTo(br.height, d.height, 2, description + "'d' and a line breaker caused by <br> in 3rd <p> should be similar height");
+  is(br.left, d.left, description + "left of a line breaker caused by <br> in 3rd <p> should be same left of 'd'");
+
+  // <br> in 3rd <p> as array
+  let brAsArray = synthesizeQueryTextRectArray(kLFLen * 3 + 6, 1);
+  if (!checkQueryContentResult(brAsArray, description + "<br> in 3rd <p> as array") ||
+      !checkRectArray(brAsArray, [br], description + "query text rect array result of <br> in 3rd <p> should match with each query text rect result")) {
+    return;
+  }
+
+  if (kLFLen > 1) {
+    // \n of \r\n
+    let br_2 = synthesizeQueryTextRect(kLFLen * 3 + 7, 1);
+    if (!checkQueryContentResult(br_2, description + "rect for \\n of \\r\\n caused by <br> in 3rd <p>")) {
+      return;
+    }
+
+    is(br_2.top, br.top, description + "'\\r' and '\\n' should be at same top");
+    is(br_2.left, br.left, description + "'\\r' and '\\n' should be at same top");
+    is(br_2.height, br.height, description + "'\\r' and '\\n' should be same height");
+    is(br_2.width, br.width, description + "'\\r' and '\\n' should be same width");
+
+    // \n of \r\n as array
+    let br_2AsArray = synthesizeQueryTextRectArray(kLFLen * 3 + 7, 1);
+    if (!checkQueryContentResult(br_2AsArray, description + "rect array for \\n of \\r\\n caused by <br> in 3rd <p>") ||
+        !checkRectArray(br_2AsArray, [br_2], description + "query text rect array result of \\n of \\r\\n caused by <br> in 3rd <p> should match with each query text rect result")) {
+      return;
+    }
+  }
+
+  // next of <br> in 3rd <p>
+  let next_br = synthesizeQueryTextRect(kLFLen * 4 + 6, 1);
+  if (!checkQueryContentResult(next_br, description + "rect for next of <br> in 3rd <p>")) {
+    return;
+  }
+
+  is(next_br.top, br.top, description + "next of <br> and <br> should be at same top");
+  is(next_br.left, br.left, description + "next of <br> and <br> should be at same left");
+  is(next_br.height, br.height, description + "next of <br> and <br> should be same height");
+  is(next_br.width, br.width, description + "next of <br> and <br> should be same width");
+
+  // next of <br> in 3rd <p> as array
+  let next_brAsArray = synthesizeQueryTextRectArray(kLFLen * 4 + 6, 1);
+  if (!checkQueryContentResult(next_brAsArray, description + "rect array for next of <br> in 3rd <p>") ||
+      !checkRectArray(next_brAsArray, [next_br], description + "query text rect array result of next of <br> in 3rd <p> should match with each query text rect result")) {
+    return;
+  }
+
+  // too big offset for the editor
+  tooBigOffset = synthesizeQueryTextRect(kLFLen * 4 + 7, 1);
+  if (!checkQueryContentResult(tooBigOffset, description + "rect for too big offset")) {
+    return;
+  }
+
+  is(tooBigOffset.top, next_br.top, description + "too big offset and next of 3rd <p> should be at same top");
+  is(tooBigOffset.left, next_br.left, description + "too big offset and next of 3rd <p> should be at same left");
+  is(tooBigOffset.height, next_br.height, description + "too big offset and next of 3rd <p> should be same height");
+  is(tooBigOffset.width, next_br.width, description + "too big offset and next of 3rd <p> should be same width");
+
+  // too big offset for the editors as array
+  tooBigOffsetAsArray = synthesizeQueryTextRectArray(kLFLen * 4 + 7, 1);
+  if (!checkQueryContentResult(tooBigOffsetAsArray, description + "rect array for too big offset") ||
+      !checkRectArray(tooBigOffsetAsArray, [tooBigOffset], description + "query text rect array result with too big offset should match with each query text rect result")) {
+    return;
+  }
+
+  contenteditable.innerHTML = "<p>abc</p><p>def</p><p></p>";
+                      // \n    0  123    4  567    8
+                      // \r\n  01 234    56 789    0
+
+  description = "runTextRectInContentEditableTest: \"" + contenteditable.innerHTML + "\", ";
+
+  // "f"
+  f = synthesizeQueryTextRect(kLFLen * 2 + 5, 1);
+  if (!checkQueryContentResult(f, description + "rect for 'f'")) {
+    return;
+  }
+
+  is(f.top, e.top, description + "'e' and 'f' should be at same top");
+  isSimilarTo(f.left, e.left + e.width, 2, description + "left of 'f' should be at similar to right of 'e'");
+  is(f.height, e.height, description + "'e' and 'f' should be same height");
+
+  // 3rd <p> (can be computed with rect of 'f')
+  p3 = synthesizeQueryTextRect(kLFLen * 2 + 6, 1);
+  if (!checkQueryContentResult(p3, description + "rect for 3rd <p>")) {
+    return;
+  }
+
+  is(p3.top, f.top, description + "'f' and a line breaker caused by 3rd <p> should be at same top");
+  is(p3.height, f.height, description + "'f' and a line breaker caused by 3rd <p> should be same height");
+  isSimilarTo(p3.left, f.left + f.width, 2, description + "left of a line breaker caused by 3rd <p> should be similar to right of 'f'");
+
+  // 3rd <p> as array
+  p3AsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 6, 1);
+  if (!checkQueryContentResult(p3AsArray, description + "3rd <p>'s line breaker as array") ||
+      !checkRectArray(p3AsArray, [p3], description + "query text rect array result of 3rd <p> should match with each query text rect result")) {
+    return;
+  }
+
+  if (kLFLen > 1) {
+    // \n of \r\n
+    let p3_2 = synthesizeQueryTextRect(kLFLen * 2 + 7, 1);
+    if (!checkQueryContentResult(p3_2, description + "rect for \\n of \\r\\n caused by 3rd <p>")) {
+      return;
+    }
+
+    is(p3_2.top, p3.top, description + "'\\r' and '\\n' should be at same top");
+    is(p3_2.left, p3.left, description + "'\\r' and '\\n' should be at same top");
+    is(p3_2.height, p3.height, description + "'\\r' and '\\n' should be same height");
+    is(p3_2.width, p3.width, description + "'\\r' and '\\n' should be same width");
+
+    // \n of \r\n as array
+    let p3_2AsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 7, 1);
+    if (!checkQueryContentResult(p3_2AsArray, description + "rect array for \\n of \\r\\n caused by 3rd <p>") ||
+        !checkRectArray(p3_2AsArray, [p3_2], description + "query text rect array result of \\n of \\r\\n caused by 3rd <p> should match with each query text rect result")) {
+      return;
+    }
+  }
+
+  // next of 3rd <p>
+  let next_p3 = synthesizeQueryTextRect(kLFLen * 3 + 6, 1);
+  if (!checkQueryContentResult(next_p3, description + "rect for next of 3rd <p>")) {
+    return;
+  }
+
+  isGreaterThan(next_p3.top, d.top + d.height, description + "top of next of 3rd <p> should equal to or be bigger than bottom of 'd'");
+  isSimilarTo(next_p3.left, d.left, 2, description + "left of next of 3rd <p> should be at similar to left of 'd'");
+  isSimilarTo(next_p3.height, d.height, 2, description + "next of 3rd <p> and 'd' should be similar height");
+
+  // next of 3rd <p> as array
+  let next_p3AsArray = synthesizeQueryTextRectArray(kLFLen * 3 + 6, 1);
+  if (!checkQueryContentResult(next_p3AsArray, description + "next of 3rd <p> as array") ||
+      !checkRectArray(next_p3AsArray, [next_p3], description + "query text rect array result of next of 3rd <p> should match with each query text rect result")) {
+    return;
+  }
+
+  // too big offset for the editor
+  tooBigOffset = synthesizeQueryTextRect(kLFLen * 3 + 7, 1);
+  if (!checkQueryContentResult(tooBigOffset, description + "rect for too big offset")) {
+    return;
+  }
+
+  is(tooBigOffset.top, next_p3.top, description + "too big offset and next of 3rd <p> should be at same top");
+  is(tooBigOffset.left, next_p3.left, description + "too big offset and next of 3rd <p> should be at same left");
+  is(tooBigOffset.height, next_p3.height, description + "too big offset and next of 3rd <p> should be same height");
+  is(tooBigOffset.width, next_p3.width, description + "too big offset and next of 3rd <p> should be same width");
+
+  // too big offset for the editors as array
+  tooBigOffsetAsArray = synthesizeQueryTextRectArray(kLFLen * 3 + 7, 1);
+  if (!checkQueryContentResult(tooBigOffsetAsArray, description + "rect array for too big offset") ||
+      !checkRectArray(tooBigOffsetAsArray, [tooBigOffset], description + "query text rect array result with too big offset should match with each query text rect result")) {
+    return;
+  }
+
+  contenteditable.innerHTML = "abc<br>def";
+                      // \n    0123   456
+                      // \r\n  01234  567
+
+  description = "runTextRectInContentEditableTest: \"" + contenteditable.innerHTML + "\", ";
+
+  // "a"
+  a = synthesizeQueryTextRect(0, 1);
+  if (!checkQueryContentResult(a, description + "rect for 'a'")) {
+    return;
+  }
+
+  // "b"
+  b = synthesizeQueryTextRect(1, 1);
+  if (!checkQueryContentResult(b, description + "rect for 'b'")) {
+    return;
+  }
+
+  is(b.top, a.top, description + "'a' and 'b' should be at same top");
+  isSimilarTo(b.left, a.left + a.width, 2, description + "left of 'b' should be at similar to right of 'a'");
+  is(b.height, a.height, description + "'a' and 'b' should be same height");
+
+  // "c"
+  c = synthesizeQueryTextRect(2, 1);
+  if (!checkQueryContentResult(c, description + "rect for 'c'")) {
+    return;
+  }
+
+  is(c.top, b.top, description + "'b' and 'c' should be at same top");
+  isSimilarTo(c.left, b.left + b.width, 2, description + "left of 'c' should be at similar to right of 'b'");
+  is(c.height, b.height, description + "'b' and 'c' should be same height");
+
+  // "abc" as array
+  abcAsArray = synthesizeQueryTextRectArray(0, 3);
+  if (!checkQueryContentResult(abcAsArray, description + "rect array for 'abc'") ||
+      !checkRectArray(abcAsArray, [a, b, c], description + "query text rect array result of 'abc' should match with each query text rect result")) {
+    return;
+  }
+
+  // <br> (can be computed with the rect of 'c')
+  br = synthesizeQueryTextRect(3, 1);
+  if (!checkQueryContentResult(br, description + "rect for <br>")) {
+    return;
+  }
+
+  is(br.top, c.top, description + "'c' and a line breaker caused by <br> should be at same top");
+  isSimilarTo(br.left, c.left + c.width, 2, description + "left of a line breaker caused by <br> should be at similar to right of 'c'");
+  is(br.height, c.height, description + "'c' and a line breaker caused by <br> should be same height");
+
+  // <br> as array
+  brAsArray = synthesizeQueryTextRectArray(3, 1);
+  if (!checkQueryContentResult(brAsArray, description + "<br>'s line breaker as array") ||
+      !checkRectArray(brAsArray, [br], description + "query text rect array result of <br> should match with each query text rect result")) {
+    return;
+  }
+
+  if (kLFLen > 1) {
+    // \n of \r\n
+    let br_2 = synthesizeQueryTextRect(4, 1);
+    if (!checkQueryContentResult(br_2, description + "rect for \n of \r\n caused by <br>")) {
+      return;
+    }
+
+    is(br_2.top, br.top, description + "'\\r' and '\\n' should be at same top");
+    is(br_2.left, br.left, description + "'\\r' and '\\n' should be at same top");
+    is(br_2.height, br.height, description + "'\\r' and '\\n' should be same height");
+    is(br_2.width, br.width, description + "'\\r' and '\\n' should be same width");
+
+    // \n of \r\n as array
+    let br_2AsArray = synthesizeQueryTextRectArray(4, 1);
+    if (!checkQueryContentResult(br_2AsArray, description + "rect array for \\n of \\r\\n caused by <br>") ||
+        !checkRectArray(br_2AsArray, [br_2], description + "query text rect array result of \\n of \\r\\n caused by <br> should match with each query text rect result")) {
+      return;
+    }
+  }
+
+  // "d"
+  d = synthesizeQueryTextRect(kLFLen + 3, 1);
+  if (!checkQueryContentResult(d, description + "rect for 'd'")) {
+    return;
+  }
+
+  isSimilarTo(d.top, a.top + a.height, 2, description + "top of 'd' should be at similar to bottom of 'a'");
+  is(d.left, a.left, description + "'a' and 'd' should be same at same left");
+  is(d.height, a.height, description + "'a' and 'd' should be same height");
+
+  // "e"
+  e = synthesizeQueryTextRect(kLFLen + 4, 1);
+  if (!checkQueryContentResult(e, description + "rect for 'e'")) {
+    return;
+  }
+
+  is(e.top, d.top, description + "'d' and 'd' should be at same top");
+  isSimilarTo(e.left, d.left + d.width, 2, description + "left of 'e' should be at similar to right of 'd'");
+  is(e.height, d.height, description + "'d' and 'e' should be same height");
+
+  // "f"
+  f = synthesizeQueryTextRect(kLFLen + 5, 1);
+  if (!checkQueryContentResult(f, description + "rect for 'f'")) {
+    return;
+  }
+
+  is(f.top, e.top, description + "'e' and 'f' should be at same top");
+  isSimilarTo(f.left, e.left + e.width, 2, description + "left of 'f' should be at similar to right of 'e'");
+  is(f.height, e.height, description + "'e' and 'f' should be same height");
+
+  // "def" as array
+  defAsArray = synthesizeQueryTextRectArray(kLFLen + 3, 3);
+  if (!checkQueryContentResult(defAsArray, description + "rect array for 'def'") ||
+      !checkRectArray(defAsArray, [d, e, f], description + "query text rect array result of 'def' should match with each query text rect result")) {
+    return;
+  }
+
+  // next of "f" (can be computed with rect of 'f')
+  next_f = synthesizeQueryTextRect(kLFLen + 6, 1);
+  if (!checkQueryContentResult(next_f, description + "rect for next of 'f'")) {
+    return;
+  }
+
+  is(next_f.top, d.top, 2, description + "'f' and next of 'f' should be at same top");
+  isSimilarTo(next_f.left, f.left + f.width, 2, description + "left of next of 'f' should be at similar to right of 'f'");
+  is(next_f.height, d.height, description + "'f' and next of 'f' should be same height");
+
+  // next of "f" as array
+  next_fAsArray = synthesizeQueryTextRectArray(kLFLen + 6, 1);
+  if (!checkQueryContentResult(next_fAsArray, description + "rect array for next of 'f'") ||
+      !checkRectArray(next_fAsArray, [next_f], description + "query text rect array result of next of 'f' should match with each query text rect result")) {
+    return;
+  }
+
+  // too big offset for the editor
+  tooBigOffset = synthesizeQueryTextRect(kLFLen + 7, 1);
+  if (!checkQueryContentResult(tooBigOffset, description + "rect for too big offset")) {
+    return;
+  }
+
+  is(tooBigOffset.top, next_f.top, description + "too big offset and next of 'f' should be at same top");
+  is(tooBigOffset.left, next_f.left, description + "too big offset and next of 'f' should be at same left");
+  is(tooBigOffset.height, next_f.height, description + "too big offset and next of 'f' should be same height");
+  is(tooBigOffset.width, next_f.width, description + "too big offset and next of 'f' should be same width");
+
+  // too big offset for the editors as array
+  tooBigOffsetAsArray = synthesizeQueryTextRectArray(kLFLen + 7, 1);
+  if (!checkQueryContentResult(tooBigOffsetAsArray, description + "rect array for too big offset") ||
+      !checkRectArray(tooBigOffsetAsArray, [tooBigOffset], description + "query text rect array result with too big offset should match with each query text rect result")) {
+    return;
+  }
+
+  // Note that this case does not have an empty line at the end.
+  contenteditable.innerHTML = "abc<br>def<br>";
+                      // \n    0123   4567
+                      // \r\n  01234  56789
+
+  description = "runTextRectInContentEditableTest: \"" + contenteditable.innerHTML + "\", ";
+
+  // "f"
+  f = synthesizeQueryTextRect(kLFLen + 5, 1);
+  if (!checkQueryContentResult(f, description + "rect for 'f'")) {
+    return;
+  }
+
+  is(f.top, e.top, description + "'e' and 'f' should be at same top");
+  is(f.height, e.height, description + "'e' and 'f' should be same height");
+  isSimilarTo(f.left, e.left + e.width, 2, description + "left of 'f' should be at similar to right of 'e'");
+
+  // 2nd <br> (can be computed with rect of 'f')
+  let br2 = synthesizeQueryTextRect(kLFLen + 6, 1);
+  if (!checkQueryContentResult(br2, description + "rect for 2nd <br>")) {
+    return;
+  }
+
+  is(br2.top, f.top, description + "'f' and a line breaker caused by 2nd <br> should be at same top");
+  is(br2.height, f.height, description + "'f' and a line breaker caused by 2nd <br> should be same height");
+  isSimilarTo(br2.left, f.left + f.width, 2, description + "left of a line breaker caused by 2nd <br> should be similar to right of 'f'");
+
+  // 2nd <br> as array
+  let br2AsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 6, 1);
+  if (!checkQueryContentResult(br2AsArray, description + "2nd <br>'s line breaker as array") ||
+      !checkRectArray(br2AsArray, [br2], description + "query text rect array result of 2nd <br> should match with each query text rect result")) {
+    return;
+  }
+
+  if (kLFLen > 1) {
+    // \n of \r\n
+    let br2_2 = synthesizeQueryTextRect(kLFLen + 7, 1);
+    if (!checkQueryContentResult(br2_2, description + "rect for \\n of \\r\\n caused by 2nd <br>")) {
+      return;
+    }
+
+    is(br2_2.top, br2.top, description + "'\\r' and '\\n' should be at same top");
+    is(br2_2.left, br2.left, description + "'\\r' and '\\n' should be at same top");
+    is(br2_2.height, br2.height, description + "'\\r' and '\\n' should be same height");
+    is(br2_2.width, br2.width, description + "'\\r' and '\\n' should be same width");
+
+    // \n of \r\n as array
+    let br2_2AsArray = synthesizeQueryTextRectArray(kLFLen + 7, 1);
+    if (!checkQueryContentResult(br2_2AsArray, description + "rect array for \\n of \\r\\n caused by 2nd <br>") ||
+        !checkRectArray(br2_2AsArray, [br2_2], description + "query text rect array result of \\n of \\r\\n caused by 2nd <br> should match with each query text rect result")) {
+      return;
+    }
+  }
+
+  // next of 2nd <br>
+  let next_br2 = synthesizeQueryTextRect(kLFLen * 2 + 6, 1);
+  if (!checkQueryContentResult(next_br2, description + "rect for next of 2nd <br>")) {
+    return;
+  }
+
+  is(next_br2.top, br2.top, description + "2nd <br> and next of 2nd <br> should be at same top");
+  is(next_br2.left, br2.left, description + "2nd <br> and next of 2nd <br> should be at same top");
+  is(next_br2.height, br2.height, description + "2nd <br> and next of 2nd <br> should be same height");
+  is(next_br2.width, br2.width, description + "2nd <br> and next of 2nd <br> should be same width");
+
+  // next of 2nd <br> as array
+  let next_br2AsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 6, 1);
+  if (!checkQueryContentResult(next_br2AsArray, description + "rect array for next of 2nd <br>") ||
+      !checkRectArray(next_br2AsArray, [next_br2], description + "query text rect array result of next of 2nd <br> should match with each query text rect result")) {
+    return;
+  }
+
+  // too big offset for the editor
+  tooBigOffset = synthesizeQueryTextRect(kLFLen * 2 + 7, 1);
+  if (!checkQueryContentResult(tooBigOffset, description + "rect for too big offset")) {
+    return;
+  }
+
+  is(tooBigOffset.top, next_br2.top, description + "too big offset and next of 2nd <br> should be at same top");
+  is(tooBigOffset.left, next_br2.left, description + "too big offset and next of 2nd <br> should be at same left");
+  is(tooBigOffset.height, next_br2.height, description + "too big offset and next of 2nd <br> should be same height");
+  is(tooBigOffset.width, next_br2.width, description + "too big offset and next of 2nd <br> should be same width");
+
+  // too big offset for the editors as array
+  tooBigOffsetAsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 7, 1);
+  if (!checkQueryContentResult(tooBigOffsetAsArray, description + "rect array for too big offset") ||
+      !checkRectArray(tooBigOffsetAsArray, [tooBigOffset], description + "query text rect array result with too big offset should match with each query text rect result")) {
+    return;
+  }
+
+  contenteditable.innerHTML = "abc<br>def<br><br>";
+                      // \n    0123   4567   8
+                      // \r\n  01234  56789  01
+
+  description = "runTextRectInContentEditableTest: \"" + contenteditable.innerHTML + "\", ";
+
+  // "f"
+  f = synthesizeQueryTextRect(kLFLen + 5, 1);
+  if (!checkQueryContentResult(f, description + "rect for 'f'")) {
+    return;
+  }
+
+  is(f.top, e.top, description + "'e' and 'f' should be at same top");
+  isSimilarTo(f.left, e.left + e.width, 2, description + "left of 'f' should be at similar to right of 'e'");
+  is(f.height, e.height, description + "'e' and 'f' should be same height");
+
+  // 2nd <br>
+  br2 = synthesizeQueryTextRect(kLFLen + 6, 1);
+  if (!checkQueryContentResult(br2, description + "rect for 2nd <br>")) {
+    return;
+  }
+
+  is(br2.top, f.top, description + "'f' and a line breaker caused by 2nd <br> should be at same top");
+  is(br2.height, f.height, description + "'f' and a line breaker caused by 2nd <br> should be same height");
+  ok(f.left < br2.left, description + "left of a line breaker caused by 2nd <br> should be bigger than left of 'f', f.left=" + f.left + ", br2.left=" + br2.left);
+
+  // 2nd <br> as array
+  br2AsArray = synthesizeQueryTextRectArray(kLFLen + 6, 1);
+  if (!checkQueryContentResult(br2AsArray, description + "2nd <br>'s line breaker as array") ||
+      !checkRectArray(br2AsArray, [br2], description + "query text rect array result of 2nd <br> should match with each query text rect result")) {
+    return;
+  }
+
+  if (kLFLen > 1) {
+    // \n of \r\n
+    let br2_2 = synthesizeQueryTextRect(kLFLen + 7, 1);
+    if (!checkQueryContentResult(br2_2, description + "rect for \\n of \\r\\n caused by 2nd <br>")) {
+      return;
+    }
+
+    is(br2_2.top, br2.top, description + "'\\r' and '\\n' should be at same top");
+    is(br2_2.left, br2.left, description + "'\\r' and '\\n' should be at same top");
+    is(br2_2.height, br2.height, description + "'\\r' and '\\n' should be same height");
+    is(br2_2.width, br2.width, description + "'\\r' and '\\n' should be same width");
+
+    // \n of \r\n as array
+    let br2_2AsArray = synthesizeQueryTextRectArray(kLFLen + 7, 1);
+    if (!checkQueryContentResult(br2_2AsArray, description + "rect array for \\n of \\r\\n caused by 2nd <br>") ||
+        !checkRectArray(br2_2AsArray, [br2_2], description + "query text rect array result of \\n of \\r\\n caused by 2nd <br> should match with each query text rect result")) {
+      return;
+    }
+  }
+
+  // 3rd <br>
+  let br3 = synthesizeQueryTextRect(kLFLen * 2 + 7, 1);
+  if (!checkQueryContentResult(br3, description + "rect for next of 3rd <br>")) {
+    return;
+  }
+
+  isSimilarTo(br3.top, d.top + d.height, 3, description + "top of next of 3rd <br> should at similar to bottom of 'd'");
+  isSimilarTo(br3.left, d.left, 2, description + "left of next of 3rd <br> should be at similar to left of 'd'");
+  isSimilarTo(br3.height, d.height, 2, description + "next of 3rd <br> and 'd' should be similar height");
+
+  // 3rd <br> as array
+  let br3AsArray = synthesizeQueryTextRectArray(kLFLen + 6, 1);
+  if (!checkQueryContentResult(br3AsArray, description + "3rd <br>'s line breaker as array") ||
+      !checkRectArray(br3AsArray, [br3], description + "query text rect array result of 3rd <br> should match with each query text rect result")) {
+    return;
+  }
+
+  if (kLFLen > 1) {
+    // \n of \r\n
+    let br3_2 = synthesizeQueryTextRect(kLFLen * 2 + 7, 1);
+    if (!checkQueryContentResult(br3_2, description + "rect for \\n of \\r\\n caused by 3rd <br>")) {
+      return;
+    }
+
+    is(br3_2.top, br3.top, description + "'\\r' and '\\n' should be at same top");
+    is(br3_2.left, br3.left, description + "'\\r' and '\\n' should be at same left");
+    is(br3_2.height, br3.height, description + "'\\r' and '\\n' should be same height");
+    is(br3_2.width, br3.width, description + "'\\r' and '\\n' should be same width");
+
+    // \n of \r\n as array
+    let br3_2AsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 7, 1);
+    if (!checkQueryContentResult(br3_2AsArray, description + "rect array for \\n of \\r\\n caused by 3rd <br>") ||
+        !checkRectArray(br3_2AsArray, [br3_2], description + "query text rect array result of \\n of \\r\\n caused by 3rd <br> should match with each query text rect result")) {
+      return;
+    }
+  }
+
+  // next of 3rd <br>
+  let next_br3 = synthesizeQueryTextRect(kLFLen * 3 + 6, 1);
+  if (!checkQueryContentResult(next_br3, description + "rect for next of 3rd <br>")) {
+    return;
+  }
+
+  is(next_br3.top, br3.top, description + "3rd <br> and next of 3rd <br> should be at same top");
+  is(next_br3.left, br3.left, description + "3rd <br> and next of 3rd <br> should be at same left");
+  is(next_br3.height, br3.height, description + "3rd <br> and next of 3rd <br> should be same height");
+  is(next_br3.width, br3.width, description + "3rd <br> and next of 3rd <br> should be same width");
+
+  // next of 3rd <br> as array
+  let next_br3AsArray = synthesizeQueryTextRectArray(kLFLen * 3 + 6, 1);
+  if (!checkQueryContentResult(next_br3AsArray, description + "rect array for next of 3rd <br>") ||
+      !checkRectArray(next_br3AsArray, [next_br3], description + "query text rect array result of next of 3rd <br> should match with each query text rect result")) {
+    return;
+  }
+
+  // too big offset for the editor
+  tooBigOffset = synthesizeQueryTextRect(kLFLen * 3 + 7, 1);
+  if (!checkQueryContentResult(tooBigOffset, description + "rect for too big offset")) {
+    return;
+  }
+
+  is(tooBigOffset.top, next_br3.top, description + "too big offset and next of 3rd <br> should be at same top");
+  is(tooBigOffset.left, next_br3.left, description + "too big offset and next of 3rd <br> should be at same left");
+  is(tooBigOffset.height, next_br3.height, description + "too big offset and next of 3rd <br> should be same height");
+  is(tooBigOffset.width, next_br3.width, description + "too big offset and next of 3rd <br> should be same width");
+
+  // too big offset for the editors as array
+  tooBigOffsetAsArray = synthesizeQueryTextRectArray(kLFLen * 2 + 7, 1);
+  if (checkQueryContentResult(tooBigOffsetAsArray, description + "rect array for too big offset")) {
+    checkRectArray(tooBigOffsetAsArray, [tooBigOffset], description + "query text rect array result with too big offset should match with each query text rect result");
+  }
+
+  if (!(function test_query_text_rects_across_invisible_text() {
+    contenteditable.innerHTML = "<div>\n<div>abc</div></div>";
+                        // \n    0    1 2    345
+                        // \r\n  01   2345   678
+    description = `runQueryTextRectInContentEditableTest: test_query_text_rects_across_invisible_text: "${
+      contenteditable.innerHTML.replace(/\n/g, "\\n")
+    }",`;
+    // rect of "a"
+    const rectA = synthesizeQueryTextRect(kLFLen * 3, 1);
+    if (!checkQueryContentResult(rectA, `${description} rect of "a"`)) {
+      return false;
+    }
+    const rectArrayFromStartToA = synthesizeQueryTextRectArray(0, kLFLen * 3 + 1);
+    if (!checkQueryContentResult(rectArrayFromStartToA, `${description} rect array from invisible text to "a"`)) {
+      return false;
+    }
+    const fromStartToARects = getRectArray(rectArrayFromStartToA);
+    if (!checkRect(
+      fromStartToARects[kLFLen * 3],
+      rectA,
+      `${description} rect for "a" in array should be same as the result of query only it`
+    )) {
+      return false;
+    }
+    return checkRect(
+      fromStartToARects[kLFLen * 2],
+      fromStartToARects[0],
+      `${description} rect for the linebreak in invisible text node should be same as first linebreak`
+    );
+  })()) {
+    return;
+  }
+
+  function test_query_text_rects_starting_from_invisible_text() {
+    contenteditable.innerHTML = "<div>\n<div>abc</div></div>";
+                        // \n    0    1 2    345
+                        // \r\n  01   2345   678
+    description = `runQueryTextRectInContentEditableTest: test_query_text_rects_starting_from_invisible_text: "${
+      contenteditable.innerHTML.replace(/\n/g, "\\n")
+    }",`;
+    // rect of "a"
+    const rectA = synthesizeQueryTextRect(kLFLen * 3, 1);
+    if (!checkQueryContentResult(rectA, `${description} rect of "a"`)) {
+      return false;
+    }
+    const rectArrayFromInvisibleToA = synthesizeQueryTextRectArray(kLFLen, kLFLen * 2 + 1);
+    if (!checkQueryContentResult(rectArrayFromInvisibleToA, `${description} rect array from invisible text to "a"`)) {
+      return false;
+    }
+    const fromInvisibleToARects = getRectArray(rectArrayFromInvisibleToA);
+    if (!checkRect(
+      fromInvisibleToARects[kLFLen * 2],
+      rectA,
+      `${description} rect for "a" in array should be same as the result of query only it`
+    )) {
+      return false;
+    }
+    // For now the rect of characters in invisible text node should be caret rect
+    // before the following line break.  This is inconsistent from the result of
+    // the query text rect array event starting from the previous visible line
+    // break or character, but users anyway cannot insert text into the invisible
+    // text node only with user's operation.  Therefore, this won't be problem
+    // in usual web apps.
+    const caretRectBeforeLineBreakBeforeA = fromInvisibleToARects[kLFLen];
+    return checkRect(
+      fromInvisibleToARects[0],
+      caretRectBeforeLineBreakBeforeA,
+      `${description} rect for the linebreak in invisible text node should be same as caret rect before the following visible linebreak before "a"`
+    );
+  }
+  if (!test_query_text_rects_starting_from_invisible_text()) {
+    return;
+  }
+
+  if (kLFLen > 1) {
+    function test_query_text_rects_starting_from_middle_of_invisible_linebreak() {
+      contenteditable.innerHTML = "<div>\n<div>abc</div></div>";
+                          // \n    0    1 2    345
+                          // \r\n  01   2345   678
+      description = `runQueryTextRectInContentEditableTest: test_query_text_rects_starting_from_middle_of_invisible_linebreak: "${
+        contenteditable.innerHTML.replace(/\n/g, "\\n")
+      }",`;
+      // rect of "a"
+      const rectA = synthesizeQueryTextRect(kLFLen * 3, 1);
+      if (!checkQueryContentResult(rectA, `${description} rect of "a"`)) {
+        return false;
+      }
+      const rectArrayFromInvisibleToA = synthesizeQueryTextRectArray(kLFLen + 1, 1 + kLFLen + 1);
+      if (!checkQueryContentResult(rectArrayFromInvisibleToA, `${description} rect array from invisible text to "a"`)) {
+        return false;
+      }
+      const fromInvisibleToARects = getRectArray(rectArrayFromInvisibleToA);
+      if (!checkRect(
+        fromInvisibleToARects[1 + kLFLen],
+        rectA,
+        `${description} rect for "a" in array should be same as the result of query only it`
+      )) {
+        return false;
+      }
+      // For now the rect of characters in invisible text node should be caret rect
+      // before the following line break.  This is inconsistent from the result of
+      // the query text rect array event starting from the previous visible line
+      // break or character, but users anyway cannot insert text into the invisible
+      // text node only with user's operation.  Therefore, this won't be problem
+      // in usual web apps.
+      const caretRectBeforeLineBreakBeforeA = fromInvisibleToARects[1];
+      return checkRect(
+        fromInvisibleToARects[0],
+        caretRectBeforeLineBreakBeforeA,
+        `${description} rect for the linebreak in invisible text node should be same as caret rect before the following visible linebreak before "a"`
+      );
+    }
+    if (!test_query_text_rects_starting_from_middle_of_invisible_linebreak()) {
+      return;
+    }
+  }
+
+  function test_query_text_rects_ending_with_invisible_text() {
+    contenteditable.innerHTML = "<div><div>abc</div>\n</div>";
+                        // \n    0    1    234      5
+                        // \r\n  01   23   456      78
+    description = `runQueryTextRectInContentEditableTest: test_query_text_rects_ending_with_invisible_text: "${
+      contenteditable.innerHTML.replace(/\n/g, "\\n")
+    }",`;
+    // rect of "c"
+    const rectC = synthesizeQueryTextRect(kLFLen * 2 + 2, 1);
+    if (!checkQueryContentResult(rectC, `${description} rect of "c"`)) {
+      return false;
+    }
+    const rectArrayFromCToInvisible = synthesizeQueryTextRectArray(kLFLen * 2 + 2, 1 + kLFLen);
+    if (!checkQueryContentResult(rectArrayFromCToInvisible, `${description} rect array from "c" to invisible linebreak`)) {
+      return false;
+    }
+    const fromCToInvisibleRects = getRectArray(rectArrayFromCToInvisible);
+    if (!checkRect(
+      fromCToInvisibleRects[0],
+      rectC,
+      `${description} rect for "c" in array should be same as the result of query only it`
+    )) {
+      return false;
+    }
+    const caretRectAfterC = {
+      left: rectC.left + rectC.width,
+      top: rectC.top,
+      width: 1,
+      height: rectC.height,
+    };
+    return checkRectFuzzy(
+      fromCToInvisibleRects[1],
+      caretRectAfterC,
+      {
+        left: 1,
+        top: 0,
+        width: 0,
+        height: 0,
+      },
+      `${description} rect for the linebreak in invisible text node should be same as caret rect after "c"`
+    );
+  }
+  if (!test_query_text_rects_ending_with_invisible_text()) {
+    // eslint-disable-next-line no-useless-return
+    return;
+  }
+}
+
+function runCharAtPointTest(aFocusedEditor, aTargetName)
+{
+  aFocusedEditor.value = "This is a test of the\nContent Events";
+                       // 012345678901234567890  12345678901234
+                       // 0         1         2           3
+
+  aFocusedEditor.focus();
+
+  const kNone = -1;
+  const kTestingOffset             = [     0, 10,    20, 21 + kLFLen, 34 + kLFLen];
+  const kLeftSideOffset            = [ kNone,  9,    19,       kNone, 33 + kLFLen];
+  const kRightSideOffset           = [     1, 11, kNone, 22 + kLFLen,       kNone];
+  const kLeftTentativeCaretOffset  = [     0, 10,    20, 21 + kLFLen, 34 + kLFLen];
+  const kRightTentativeCaretOffset = [     1, 11,    21, 22 + kLFLen, 35 + kLFLen];
+
+  let editorRect = synthesizeQueryEditorRect();
+  if (!checkQueryContentResult(editorRect,
+        "runCharAtPointTest (" + aTargetName + "): editorRect")) {
+    return;
+  }
+
+  for (let i = 0; i < kTestingOffset.length; i++) {
+    let textRect = synthesizeQueryTextRect(kTestingOffset[i], 1);
+    if (!checkQueryContentResult(textRect,
+          "runCharAtPointTest (" + aTargetName + "): textRect: i=" + i)) {
+      continue;
+    }
+
+    checkRectContainsRect(textRect, editorRect,
+      "runCharAtPointTest (" + aTargetName +
+      "): the text rect isn't in the editor");
+
+    // Test #1, getting same character rect by the point near the top-left.
+    let charAtPt1 = synthesizeCharAtPoint(textRect.left + 1,
+                                          textRect.top + 1);
+    if (checkQueryContentResult(charAtPt1,
+          "runCharAtPointTest (" + aTargetName + "): charAtPt1: i=" + i)) {
+      ok(!charAtPt1.notFound,
+         "runCharAtPointTest (" + aTargetName + "): charAtPt1 isn't found: i=" + i);
+      if (!charAtPt1.notFound) {
+        is(charAtPt1.offset, kTestingOffset[i],
+           "runCharAtPointTest (" + aTargetName + "): charAtPt1 offset is wrong: i=" + i);
+        checkRect(charAtPt1, textRect, "runCharAtPointTest (" + aTargetName +
+                  "): charAtPt1 left is wrong: i=" + i);
+      }
+      ok(!charAtPt1.tentativeCaretOffsetNotFound,
+         "runCharAtPointTest (" + aTargetName + "): tentative caret offset for charAtPt1 isn't found: i=" + i);
+      if (!charAtPt1.tentativeCaretOffsetNotFound) {
+        is(charAtPt1.tentativeCaretOffset, kLeftTentativeCaretOffset[i],
+           "runCharAtPointTest (" + aTargetName + "): tentative caret offset for charAtPt1 is wrong: i=" + i);
+      }
+    }
+
+    // Test #2, getting same character rect by the point near the bottom-right.
+    let charAtPt2 = synthesizeCharAtPoint(textRect.left + textRect.width - 2,
+                                          textRect.top + textRect.height - 2);
+    if (checkQueryContentResult(charAtPt2,
+          "runCharAtPointTest (" + aTargetName + "): charAtPt2: i=" + i)) {
+      ok(!charAtPt2.notFound,
+         "runCharAtPointTest (" + aTargetName + "): charAtPt2 isn't found: i=" + i);
+      if (!charAtPt2.notFound) {
+        is(charAtPt2.offset, kTestingOffset[i],
+           "runCharAtPointTest (" + aTargetName + "): charAtPt2 offset is wrong: i=" + i);
+        checkRect(charAtPt2, textRect, "runCharAtPointTest (" + aTargetName +
+                  "): charAtPt1 left is wrong: i=" + i);
+      }
+      ok(!charAtPt2.tentativeCaretOffsetNotFound,
+         "runCharAtPointTest (" + aTargetName + "): tentative caret offset for charAtPt2 isn't found: i=" + i);
+      if (!charAtPt2.tentativeCaretOffsetNotFound) {
+        is(charAtPt2.tentativeCaretOffset, kRightTentativeCaretOffset[i],
+           "runCharAtPointTest (" + aTargetName + "): tentative caret offset for charAtPt2 is wrong: i=" + i);
+      }
+    }
+
+    // Test #3, getting left character offset.
+    let charAtPt3 = synthesizeCharAtPoint(textRect.left - 2,
+                                          textRect.top + 1);
+    if (checkQueryContentResult(charAtPt3,
+          "runCharAtPointTest (" + aTargetName + "): charAtPt3: i=" + i)) {
+      is(charAtPt3.notFound, kLeftSideOffset[i] == kNone,
+         kLeftSideOffset[i] == kNone ?
+           "runCharAtPointTest (" + aTargetName + "): charAtPt3 is found: i=" + i :
+           "runCharAtPointTest (" + aTargetName + "): charAtPt3 isn't found: i=" + i);
+      if (!charAtPt3.notFound) {
+        is(charAtPt3.offset, kLeftSideOffset[i],
+           "runCharAtPointTest (" + aTargetName + "): charAtPt3 offset is wrong: i=" + i);
+      }
+      if (kLeftSideOffset[i] == kNone) {
+        // There may be no enough padding-left (depends on platform)
+        todo(false,
+             "runCharAtPointTest (" + aTargetName + "): tentative caret offset for charAtPt3 isn't tested: i=" + i);
+      } else {
+        ok(!charAtPt3.tentativeCaretOffsetNotFound,
+           "runCharAtPointTest (" + aTargetName + "): tentative caret offset for charAtPt3 isn't found: i=" + i);
+        if (!charAtPt3.tentativeCaretOffsetNotFound) {
+          is(charAtPt3.tentativeCaretOffset, kLeftTentativeCaretOffset[i],
+             "runCharAtPointTest (" + aTargetName + "): tentative caret offset for charAtPt3 is wrong: i=" + i);
+        }
+      }
+    }
+
+    // Test #4, getting right character offset.
+    let charAtPt4 = synthesizeCharAtPoint(textRect.left + textRect.width + 1,
+                                          textRect.top + textRect.height - 2);
+    if (checkQueryContentResult(charAtPt4,
+          "runCharAtPointTest (" + aTargetName + "): charAtPt4: i=" + i)) {
+      is(charAtPt4.notFound, kRightSideOffset[i] == kNone,
+         kRightSideOffset[i] == kNone ?
+           "runCharAtPointTest (" + aTargetName + "): charAtPt4 is found: i=" + i :
+           "runCharAtPointTest (" + aTargetName + "): charAtPt4 isn't found: i=" + i);
+      if (!charAtPt4.notFound) {
+        is(charAtPt4.offset, kRightSideOffset[i],
+           "runCharAtPointTest (" + aTargetName + "): charAtPt4 offset is wrong: i=" + i);
+      }
+      ok(!charAtPt4.tentativeCaretOffsetNotFound,
+         "runCharAtPointTest (" + aTargetName + "): tentative caret offset for charAtPt4 isn't found: i=" + i);
+      if (!charAtPt4.tentativeCaretOffsetNotFound) {
+        is(charAtPt4.tentativeCaretOffset, kRightTentativeCaretOffset[i],
+           "runCharAtPointTest (" + aTargetName + "): tentative caret offset for charAtPt4 is wrong: i=" + i);
+      }
+    }
+  }
+}
+
+function runCharAtPointAtOutsideTest()
+{
+  textarea.focus();
+  textarea.value = "some text";
+  let editorRect = synthesizeQueryEditorRect();
+  if (!checkQueryContentResult(editorRect,
+        "runCharAtPointAtOutsideTest: editorRect")) {
+    return;
+  }
+  // Check on a text node which is at the outside of editor.
+  let charAtPt = synthesizeCharAtPoint(editorRect.left + 20,
+                                       editorRect.top - 10);
+  if (checkQueryContentResult(charAtPt,
+        "runCharAtPointAtOutsideTest: charAtPt")) {
+    ok(charAtPt.notFound,
+       "runCharAtPointAtOutsideTest: charAtPt is found on outside of editor");
+    ok(charAtPt.tentativeCaretOffsetNotFound,
+       "runCharAtPointAtOutsideTest: tentative caret offset for charAtPt is found on outside of editor");
+  }
+}
+
+async function runSetSelectionEventTest()
+{
+  contenteditable.focus();
+
+  const selection = windowOfContenteditable.getSelection();
+
+  // #1
+  contenteditable.innerHTML = "abc<br>def";
+
+  await synthesizeSelectionSet(0, 100);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #1 (0, 100), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first text node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #1 (0, 100), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #1 (0, 100), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node of the editor");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #1 (0, 100), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of children");
+  checkSelection(0, "abc" + kLF + "def", "runSetSelectionEventTest #1 (0, 100), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(2, 2 + kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #1 (2, 2+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first text node");
+  is(selection.anchorOffset, 2,
+     "runSetSelectionEventTest #1 (2, 2+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 2");
+  is(selection.focusNode, contenteditable.lastChild,
+     "runSetSelectionEventTest #1 (2, 2+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the last text node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #1 (2, 2+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(2, "c" + kLF + "d", "runSetSelectionEventTest #1 (2, 2+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(1, 2);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #1 (1, 2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first text node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #1 (1, 2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #1 (1, 2), \"" + contenteditable.innerHTML + "\": selection focus node should be the first text node");
+  is(selection.focusOffset, contenteditable.firstChild.wholeText.length,
+     "runSetSelectionEventTest #1 (1, 2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the text node");
+  checkSelection(1, "bc", "runSetSelectionEventTest #1 (1, 2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(3, kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #1 (3, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first text node");
+  is(selection.anchorOffset, contenteditable.firstChild.wholeText.length,
+     "runSetSelectionEventTest #1 (3, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the first text node");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #1 (3, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, 2,
+     "runSetSelectionEventTest #1 (3, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be the index of the last text node");
+  checkSelection(3, kLF, "runSetSelectionEventTest #1 (3, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(6+kLFLen, 0);
+  is(selection.anchorNode, contenteditable.lastChild,
+     "runSetSelectionEventTest #1 (6+kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node");
+  is(selection.anchorOffset, contenteditable.lastChild.wholeText.length,
+     "runSetSelectionEventTest #1 (6+kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the last text node");
+  is(selection.focusNode, contenteditable.lastChild,
+     "runSetSelectionEventTest #1 (6+kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the last text node");
+  is(selection.anchorOffset, contenteditable.lastChild.wholeText.length,
+     "runSetSelectionEventTest #1 (6+kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the last text node");
+  checkSelection(6 + kLFLen, "", "runSetSelectionEventTest #1 (6+kLFLen, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(100, 0);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #1 (100, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node of the editor");
+  is(selection.anchorOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #1 (100, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the count of children");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #1 (100, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node of the editor");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #1 (100, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of children");
+  checkSelection(6 + kLFLen, "", "runSetSelectionEventTest #1 (100, 0), \"" + contenteditable.innerHTML + "\"");
+
+  // #2
+  contenteditable.innerHTML = "<p>a<b>b</b>c</p><p>def</p>";
+
+  await synthesizeSelectionSet(kLFLen, 4+kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #2 (kLFLen, 4+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first <p> node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #2 (kLFLen, 4+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the first <p> node");
+  is(selection.focusNode, contenteditable.lastChild.firstChild,
+     "runSetSelectionEventTest #2 (kLFLen, 4+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node in the second <p> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #2 (kLFLen, 4+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(kLFLen, "abc" + kLF + "d", "runSetSelectionEventTest #2 (kLFLen, 4+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen, 2);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #2 (kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first <p> node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #2 (kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the first <p> node");
+  is(selection.focusNode, contenteditable.firstChild.childNodes.item(1).firstChild,
+     "runSetSelectionEventTest #2 (kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node in the <b> node");
+  is(selection.focusOffset, contenteditable.firstChild.childNodes.item(1).firstChild.wholeText.length,
+     "runSetSelectionEventTest #2 (kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the text node in the <b> node");
+  checkSelection(kLFLen, "ab", "runSetSelectionEventTest #2 (kLFLen, 2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(1+kLFLen, 2);
+  is(selection.anchorNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #2 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first text node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #2 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #2 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection focus node should be the last text node in the first <p> node");
+  is(selection.focusOffset, contenteditable.firstChild.lastChild.wholeText.length,
+     "runSetSelectionEventTest #2 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the last text node in the first <p> node");
+  checkSelection(1+kLFLen, "bc", "runSetSelectionEventTest #2 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(2+kLFLen, 2+kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild.childNodes.item(1).firstChild,
+     "runSetSelectionEventTest #2 (2+kLFLen, 2+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the text node in the <b> node");
+  is(selection.anchorOffset, contenteditable.firstChild.childNodes.item(1).firstChild.wholeText.length,
+     "runSetSelectionEventTest #2 (2+kLFLen, 2+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the text node in the <b> node");
+  is(selection.focusNode, contenteditable.lastChild.firstChild,
+     "runSetSelectionEventTest #2 (2+kLFLen, 2+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node in the last <p> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #2 (2+kLFLen, 2+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(2+kLFLen, "c" + kLF + "d", "runSetSelectionEventTest #2 (2+kLFLen, 2+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(3+kLFLen*2, 1);
+  is(selection.anchorNode, contenteditable.lastChild,
+     "runSetSelectionEventTest #2 (3+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection anchor node should be the second <p> node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #2 (3+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the second <p> node");
+  is(selection.focusNode, contenteditable.lastChild.firstChild,
+     "runSetSelectionEventTest #2 (3+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node in the second <p> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #2 (3+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(3+kLFLen*2, "d", "runSetSelectionEventTest #2 (3+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, 0);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #2 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #2 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #2 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #2 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, "", "runSetSelectionEventTest #2 (0, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, kLFLen);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #2 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #2 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the first <p> node");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #2 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the first <p> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #2 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, kLF, "runSetSelectionEventTest #2 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(2+kLFLen, 1+kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild.childNodes.item(1).firstChild,
+     "runSetSelectionEventTest #2 (2+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node of the <b> node");
+  is(selection.anchorOffset, contenteditable.firstChild.childNodes.item(1).firstChild.wholeText.length,
+     "runSetSelectionEventTest #2 (2+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the last text node of the first <b> node");
+  is(selection.focusNode, contenteditable.lastChild,
+     "runSetSelectionEventTest #2 (2+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the second <p> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #2 (2+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(2+kLFLen, "c" + kLF, "runSetSelectionEventTest #2 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(3+kLFLen, kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #2 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node of the first <p> node");
+  is(selection.anchorOffset, contenteditable.firstChild.lastChild.wholeText.length,
+     "runSetSelectionEventTest #2 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the last text node of the first <p> node");
+  is(selection.focusNode, contenteditable.lastChild,
+     "runSetSelectionEventTest #2 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the second <p> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #2 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(3+kLFLen, kLF, "runSetSelectionEventTest #2 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(3+kLFLen, 1+kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #2 (3+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node of the first <p> node");
+  is(selection.anchorOffset, contenteditable.firstChild.lastChild.wholeText.length,
+     "runSetSelectionEventTest #2 (3+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the last text node of the first <p> node");
+  is(selection.focusNode, contenteditable.lastChild.firstChild,
+     "runSetSelectionEventTest #2 (3+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node of the second <p> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #2 (3+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(3+kLFLen, kLF + "d", "runSetSelectionEventTest #2 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  // #3
+  contenteditable.innerHTML = "<div>abc<p>def</p></div>";
+
+  await synthesizeSelectionSet(1+kLFLen, 2);
+  is(selection.anchorNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #3 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first text node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #3 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #3 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection focus node should be the first text node");
+  is(selection.focusOffset, contenteditable.firstChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #3 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the first text node");
+  checkSelection(1+kLFLen, "bc", "runSetSelectionEventTest #3 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(1+kLFLen, 3+kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #3 (1+kLFLen, 3+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first text node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #3 (1+kLFLen, 3+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.firstChild.lastChild.firstChild,
+     "runSetSelectionEventTest #3 (1+kLFLen, 3+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node in the <p> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #3 (1+kLFLen, 3+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(1+kLFLen, "bc" + kLF + "d", "runSetSelectionEventTest #3 (1+kLFLen, 3+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(3+kLFLen, 0);
+  is(selection.anchorNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #3 (3+kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first text node");
+  is(selection.anchorOffset, contenteditable.firstChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #3 (3+kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the first text node");
+  is(selection.focusNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #3 (3+kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the first text node");
+  is(selection.focusOffset, contenteditable.firstChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #3 (3+kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the first text node");
+  checkSelection(3+kLFLen, "", "runSetSelectionEventTest #3 (3+kLFLen, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, 6+kLFLen*2);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #3 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #3 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.firstChild.lastChild.firstChild,
+     "runSetSelectionEventTest #3 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus node should be the last text node");
+  is(selection.focusOffset, contenteditable.firstChild.lastChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #3 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the last text node");
+  checkSelection(0, kLF + "abc" + kLF + "def", "runSetSelectionEventTest #3 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, 100);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #3 (0, 100), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #3 (0, 100), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #3 (0, 100), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #3 (0, 100), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(0, kLF + "abc" + kLF + "def", "runSetSelectionEventTest #3 (0, 100), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(4+kLFLen*2, 2);
+  is(selection.anchorNode, contenteditable.firstChild.lastChild.firstChild,
+     "runSetSelectionEventTest #3 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #3 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.firstChild.lastChild.firstChild,
+     "runSetSelectionEventTest #3 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection focus node should be the last text node");
+  is(selection.focusOffset, contenteditable.firstChild.lastChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #3 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the last text node");
+  checkSelection(4+kLFLen*2, "ef", "runSetSelectionEventTest #3 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(4+kLFLen*2, 100);
+  is(selection.anchorNode, contenteditable.firstChild.lastChild.firstChild,
+     "runSetSelectionEventTest #3 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #3 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #3 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #3 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(4+kLFLen*2, "ef", "runSetSelectionEventTest #3 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(6+kLFLen*2, 0);
+  is(selection.anchorNode, contenteditable.firstChild.lastChild.firstChild,
+     "runSetSelectionEventTest #3 (6+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node");
+  is(selection.anchorOffset, contenteditable.firstChild.lastChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #3 (6+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the last text node");
+  is(selection.focusNode, contenteditable.firstChild.lastChild.firstChild,
+     "runSetSelectionEventTest #3 (6+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the last text node");
+  is(selection.focusOffset, contenteditable.firstChild.lastChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #3 (6+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the last text node");
+  checkSelection(6+kLFLen*2, "", "runSetSelectionEventTest #3 (6+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(6+kLFLen*2, 1);
+  is(selection.anchorNode, contenteditable.firstChild.lastChild.firstChild,
+     "runSetSelectionEventTest #3 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node");
+  is(selection.anchorOffset, contenteditable.firstChild.lastChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #3 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the last text node");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #3 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #3 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(6+kLFLen*2, "", "runSetSelectionEventTest #3 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, kLFLen);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #3 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #3 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the first text node");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #3 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the <div> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #3 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, kLF, "runSetSelectionEventTest #3 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, 1+kLFLen);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #3 (0, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #3 (0, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the <div> node");
+  is(selection.focusNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #3 (0, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the first text node of the <div> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #3 (0, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(0, kLF + "a", "runSetSelectionEventTest #3 (0, 1+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(2+kLFLen, 1+kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #3 (2+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the text node of the <div> node");
+  is(selection.anchorOffset, 2,
+     "runSetSelectionEventTest #3 (2+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 2");
+  is(selection.focusNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #3 (2+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #3 (2+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(2+kLFLen, "c" + kLF, "runSetSelectionEventTest #3 (2+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(3+kLFLen, kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #3 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the text node of the <div> node");
+  is(selection.anchorOffset, contenteditable.firstChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #3 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the text node of the <div> node");
+  is(selection.focusNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #3 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #3 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(3+kLFLen, kLF, "runSetSelectionEventTest #3 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(3+kLFLen, 1+kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #3 (3+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the text node of the <div> node");
+  is(selection.anchorOffset, contenteditable.firstChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #3 (3+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the text node of the <div> node");
+  is(selection.focusNode, contenteditable.firstChild.lastChild.firstChild,
+     "runSetSelectionEventTest #3 (3+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node of the <p> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #3 (3+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(3+kLFLen, kLF + "d", "runSetSelectionEventTest #3 (3+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  // #4
+  contenteditable.innerHTML = "<div><p>abc</p>def</div>";
+
+  await synthesizeSelectionSet(1+kLFLen*2, 2);
+  is(selection.anchorNode, contenteditable.firstChild.firstChild.firstChild,
+     "runSetSelectionEventTest #4 (1+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the text node in the <p> node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #4 (1+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.firstChild.firstChild.firstChild,
+     "runSetSelectionEventTest #4 (1+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node in the <p> node");
+  is(selection.focusOffset, contenteditable.firstChild.firstChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #4 (1+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the text node in the <p> node");
+  checkSelection(1+kLFLen*2, "bc", "runSetSelectionEventTest #4 (1+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(1+kLFLen*2, 3);
+  is(selection.anchorNode, contenteditable.firstChild.firstChild.firstChild,
+     "runSetSelectionEventTest #4 (1+kLFLen*2, 3), \"" + contenteditable.innerHTML + "\": selection anchor node should be the text node in the <p> node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #4 (1+kLFLen*2, 3), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #4 (1+kLFLen*2, 3), \"" + contenteditable.innerHTML + "\": selection focus node should be the last text node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #4 (1+kLFLen*2, 3), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(1+kLFLen*2, "bcd", "runSetSelectionEventTest #4 (1+kLFLen*2, 3), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(3+kLFLen*2, 0);
+  is(selection.anchorNode, contenteditable.firstChild.firstChild.firstChild,
+     "runSetSelectionEventTest #4 (3+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the text node in the <p> node");
+  is(selection.anchorOffset, contenteditable.firstChild.firstChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #4 (3+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the text node in the <p> node");
+  is(selection.focusNode, contenteditable.firstChild.firstChild.firstChild,
+     "runSetSelectionEventTest #4 (3+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node in the <p> node");
+  is(selection.focusOffset, contenteditable.firstChild.firstChild.firstChild.wholeText.length,
+     "runSetSelectionEventTest #4 (3+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the text node in the <p> node");
+  checkSelection(3+kLFLen*2, "", "runSetSelectionEventTest #4 (3+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, 6+kLFLen*2);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #4 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #4 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #4 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus node should be the last text node");
+  is(selection.focusOffset, contenteditable.firstChild.lastChild.wholeText.length,
+     "runSetSelectionEventTest #4 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the last text node");
+  checkSelection(0, kLF + kLF + "abcdef", "runSetSelectionEventTest #4 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, 100);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #4 (0, 100), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #4 (0, 100), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #4 (0, 100), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #4 (0, 100), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(0, kLF + kLF + "abcdef", "runSetSelectionEventTest #4 (0, 100), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(4+kLFLen*2, 2);
+  is(selection.anchorNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #4 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #4 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #4 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection focus node should be the last text node");
+  is(selection.focusOffset, contenteditable.firstChild.lastChild.wholeText.length,
+     "runSetSelectionEventTest #4 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the last text node");
+  checkSelection(4+kLFLen*2, "ef", "runSetSelectionEventTest #4 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(4+kLFLen*2, 100);
+  is(selection.anchorNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #4 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #4 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #4 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #4 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(4+kLFLen*2, "ef", "runSetSelectionEventTest #4 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(6+kLFLen*2, 0);
+  is(selection.anchorNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #4 (6+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node");
+  is(selection.anchorOffset, contenteditable.firstChild.lastChild.wholeText.length,
+     "runSetSelectionEventTest #4 (6+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the last text node");
+  is(selection.focusNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #4 (6+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the last text node");
+  is(selection.focusOffset, contenteditable.firstChild.lastChild.wholeText.length,
+     "runSetSelectionEventTest #4 (6+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the last text node");
+  checkSelection(6+kLFLen*2, "", "runSetSelectionEventTest #4 (6+kLFLen*2, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(6+kLFLen*2, 1);
+  is(selection.anchorNode, contenteditable.firstChild.lastChild,
+     "runSetSelectionEventTest #4 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection anchor node should be the last text node");
+  is(selection.anchorOffset, contenteditable.firstChild.lastChild.wholeText.length,
+     "runSetSelectionEventTest #4 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the length of the last text node");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #4 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #4 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(6+kLFLen*2, "", "runSetSelectionEventTest #4 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, kLFLen);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #4 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #4 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the <div> node");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #4 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the <div> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #4 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, kLF, "runSetSelectionEventTest #4 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, kLFLen*2);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #4 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #4 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the <div> node");
+  is(selection.focusNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #4 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #4 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, kLF + kLF, "runSetSelectionEventTest #4 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, 1+kLFLen*2);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #4 (0, 1+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #4 (0, 1+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the <div> node");
+  is(selection.focusNode, contenteditable.firstChild.firstChild.firstChild,
+     "runSetSelectionEventTest #4 (0, 1+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node in the <p> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #4 (0, 1+kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(0, kLF + kLF + "a", "runSetSelectionEventTest #4 (0, 1+kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen, 0);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #4 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <div> node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #4 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #4 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the <div> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #4 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(kLFLen, "", "runSetSelectionEventTest #4 (kLFLen, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen, kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #4 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <div> node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #4 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the <p> node");
+  is(selection.focusNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #4 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #4 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(kLFLen, kLF, "runSetSelectionEventTest #4 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen, 1+kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #4 (kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <div> node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #4 (kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the <p> node");
+  is(selection.focusNode, contenteditable.firstChild.firstChild.firstChild,
+     "runSetSelectionEventTest #4 (kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node in the <p> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #4 (kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(kLFLen, kLF +"a", "runSetSelectionEventTest #4 (kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  // #5
+  contenteditable.innerHTML = "<br>";
+
+  await synthesizeSelectionSet(0, 0);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #5 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #5 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #5 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #5 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, "", "runSetSelectionEventTest #5 (0, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, kLFLen);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #5 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #5 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #5 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #5 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(0, kLF, "runSetSelectionEventTest #5 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen, 0);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #5 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #5 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the count of the root's children");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #5 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #5 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(kLFLen, "", "runSetSelectionEventTest #5 (kLFLen, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen, 1);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #5 (kLFLen, 1), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #5 (kLFLen, 1), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the count of the root's children");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #5 (kLFLen, 1), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #5 (kLFLen, 1), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(kLFLen, "", "runSetSelectionEventTest #5 (kLFLen, 1), \"" + contenteditable.innerHTML + "\"");
+
+  // #6
+  contenteditable.innerHTML = "<p><br></p>";
+
+  await synthesizeSelectionSet(kLFLen, kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #6 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <p> node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #6 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #6 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, contenteditable.firstChild.childNodes.length,
+     "runSetSelectionEventTest #6 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the <p>'s children");
+  checkSelection(kLFLen, kLF, "runSetSelectionEventTest #6 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen*2, 0);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #6 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <p> node");
+  is(selection.anchorOffset, contenteditable.firstChild.childNodes.length,
+     "runSetSelectionEventTest #6 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the count of the <p>'s children");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #6 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, contenteditable.firstChild.childNodes.length,
+     "runSetSelectionEventTest #6 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the <p>'s children");
+  checkSelection(kLFLen*2, "", "runSetSelectionEventTest #6 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen*2, 1);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #6 (kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <p> node");
+  is(selection.anchorOffset, contenteditable.firstChild.childNodes.length,
+     "runSetSelectionEventTest #6 (kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the count of the root's children");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #6 (kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #6 (kLFLen*2, 1), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(kLFLen*2, "", "runSetSelectionEventTest #6 (kLFLen*2, 1), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, kLFLen);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #6 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #6 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #6 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #6 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, kLF, "runSetSelectionEventTest #6 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, kLFLen*2);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #6 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #6 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #6 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, contenteditable.firstChild.childNodes.length,
+     "runSetSelectionEventTest #6 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the <p>'s children");
+  checkSelection(0, kLF + kLF, "runSetSelectionEventTest #6 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen, 0);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #6 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <p> node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #6 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #6 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #6 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(kLFLen, "", "runSetSelectionEventTest #6 (kLFLen, 0), \"" + contenteditable.innerHTML + "\"");
+
+  // #7
+  contenteditable.innerHTML = "<br><br>";
+
+  await synthesizeSelectionSet(0, kLFLen);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #7 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #7 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #7 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #7 (0, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(0, kLF, "runSetSelectionEventTest #7 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, kLFLen * 2);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #7 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #7 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #7 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #7 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(0, kLF + kLF, "runSetSelectionEventTest #7 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen, 0);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #7 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #7 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #7 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #7 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(kLFLen, "", "runSetSelectionEventTest #7 (kLFLen, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen, kLFLen);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #7 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #7 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #7 (kLFLen, kLFLen) selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #7 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(kLFLen, kLF, "runSetSelectionEventTest #7 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen * 2, 0);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #7 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #7 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the count of the root's children");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #7 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #7 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(kLFLen * 2, "", "runSetSelectionEventTest #7 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\"");
+
+  // #8
+  contenteditable.innerHTML = "<p><br><br></p>";
+
+  await synthesizeSelectionSet(kLFLen, kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #8 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <p> node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #8 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #8 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #8 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(kLFLen, kLF, "runSetSelectionEventTest #7 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen, kLFLen * 2);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #8 (kLFLen, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <p> node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #8 (kLFLen, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #8 (kLFLen, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, contenteditable.firstChild.childNodes.length,
+     "runSetSelectionEventTest #8 (kLFLen, kLFLen*2), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the <p>'s children");
+  checkSelection(kLFLen, kLF + kLF, "runSetSelectionEventTest #8 (kLFLen, kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen*2, 0);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #8 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <p> node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #8 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #8 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #8 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 1");
+  checkSelection(kLFLen*2, "", "runSetSelectionEventTest #8 (kLFLen*2, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen*2, kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #8 (kLFLen*2, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <p> node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #8 (kLFLen*2, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #8 (kLFLen*2, kLFLen) selection focus node should be the <p> node");
+  is(selection.focusOffset, contenteditable.firstChild.childNodes.length,
+     "runSetSelectionEventTest #8 (kLFLen*2, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the <p>'s children");
+  checkSelection(kLFLen*2, kLF, "runSetSelectionEventTest #8 (kLFLen*2, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen*3, 0);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #8 (kLFLen*3, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the <p> node");
+  is(selection.anchorOffset, contenteditable.firstChild.childNodes.length,
+     "runSetSelectionEventTest #8 (kLFLen*3, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the count of the <p>'s children");
+  is(selection.focusNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #8 (kLFLen*3, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, contenteditable.firstChild.childNodes.length,
+     "runSetSelectionEventTest #8 (kLFLen*3, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the <p>'s children");
+  checkSelection(kLFLen*3, "", "runSetSelectionEventTest #8 (kLFLen*3, 0), \"" + contenteditable.innerHTML + "\"");
+
+  // #9 (ContentEventHandler cannot distinguish if <p> can have children, so, the result is same as case #5, "<br>")
+  contenteditable.innerHTML = "<p></p>";
+
+  await synthesizeSelectionSet(kLFLen, 0);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #9 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #9 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the <p> node + 1");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #9 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the <p> node");
+  is(selection.focusOffset, 1,
+     "runSetSelectionEventTest #9 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be the index of the <p> node + 1");
+  checkSelection(kLFLen, "", "runSetSelectionEventTest #9 (kLFLen, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(kLFLen, 1);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #9 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #9 (kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be the index of the <p> node + 1");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #9 (kLFLen, 1), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #9 (kLFLen, 1), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(kLFLen, "", "runSetSelectionEventTest #9 (kLFLen, 0), \"" + contenteditable.innerHTML + "\"");
+
+  // #10
+  contenteditable.innerHTML = "";
+
+  await synthesizeSelectionSet(0, 0);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #10 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #10 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #10 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #10 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, "", "runSetSelectionEventTest #10 (0, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, 1);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #10 (0, 1), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #10 (0, 1), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #10 (0, 1), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #10 (0, 1), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, "", "runSetSelectionEventTest #10 (0, 1), \"" + contenteditable.innerHTML + "\"");
+
+  // #11
+  contenteditable.innerHTML = "<span></span><i><u></u></i>";
+
+  await synthesizeSelectionSet(0, 0);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #11 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #11 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #11 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #11 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, "", "runSetSelectionEventTest #11 (0, 0), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(0, 1);
+  is(selection.anchorNode, contenteditable,
+     "runSetSelectionEventTest #11 (0, 1), \"" + contenteditable.innerHTML + "\": selection anchor node should be the root node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #11 (0, 1), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable,
+     "runSetSelectionEventTest #11 (0, 1), \"" + contenteditable.innerHTML + "\": selection focus node should be the root node");
+  is(selection.focusOffset, contenteditable.childNodes.length,
+     "runSetSelectionEventTest #11 (0, 1), \"" + contenteditable.innerHTML + "\": selection focus offset should be the count of the root's children");
+  checkSelection(0, "", "runSetSelectionEventTest #11 (0, 1), \"" + contenteditable.innerHTML + "\"");
+
+  // #12
+  contenteditable.innerHTML = "<span>abc</span><i><u></u></i>";
+  selection.selectAllChildren(contenteditable);
+
+  await synthesizeSelectionSet(0, 0);
+  is(selection.anchorNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #12 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the text node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #12 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.firstChild.firstChild,
+     "runSetSelectionEventTest #12 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #12 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, "", "runSetSelectionEventTest #12 (0, 0), \"" + contenteditable.innerHTML + "\"");
+
+  // #13
+  contenteditable.innerHTML = "<span></span><i>abc<u></u></i>";
+  selection.selectAllChildren(contenteditable);
+
+  await synthesizeSelectionSet(0, 0);
+  is(selection.anchorNode, contenteditable.childNodes.item(1).firstChild,
+     "runSetSelectionEventTest #13 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the text node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #13 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.childNodes.item(1).firstChild,
+     "runSetSelectionEventTest #13 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #13 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, "", "runSetSelectionEventTest #13 (0, 0), \"" + contenteditable.innerHTML + "\"");
+
+  // #14
+  contenteditable.innerHTML = "<span></span><i><u>abc</u></i>";
+  selection.selectAllChildren(contenteditable);
+
+  await synthesizeSelectionSet(0, 0);
+  is(selection.anchorNode, contenteditable.childNodes.item(1).firstChild.firstChild,
+     "runSetSelectionEventTest #14 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the text node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #14 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.childNodes.item(1).firstChild.firstChild,
+     "runSetSelectionEventTest #14 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #14 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, "", "runSetSelectionEventTest #14 (0, 0), \"" + contenteditable.innerHTML + "\"");
+
+  // #15
+  contenteditable.innerHTML = "<span></span><i><u></u>abc</i>";
+  selection.selectAllChildren(contenteditable);
+
+  await synthesizeSelectionSet(0, 0);
+  is(selection.anchorNode, contenteditable.childNodes.item(1).lastChild,
+     "runSetSelectionEventTest #15 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the text node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #15 (0, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.childNodes.item(1).lastChild,
+     "runSetSelectionEventTest #15 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the text node");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #15 (0, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(0, "", "runSetSelectionEventTest #15 (0, 0), \"" + contenteditable.innerHTML + "\"");
+
+  // #16
+  contenteditable.innerHTML = "a<blink>b</blink>c";
+  await synthesizeSelectionSet(0, 3);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #16 (0, 3), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first text node");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #16 (0, 3), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.lastChild,
+     "runSetSelectionEventTest #16 (0, 3), \"" + contenteditable.innerHTML + "\": selection focus node should be the last text node");
+  is(selection.focusOffset, contenteditable.lastChild.wholeText.length,
+     "runSetSelectionEventTest #16 (0, 3), \"" + contenteditable.innerHTML + "\": selection focus offset should be the length of the last text node");
+  checkSelection(0, "abc", "runSetSelectionEventTest #16 (0, 3), \"" + contenteditable.innerHTML + "\"");
+
+  // #17 (bug 1319660 - incorrect adjustment of content iterator last node)
+  contenteditable.innerHTML = "<div>a</div><div><br></div>";
+
+  await synthesizeSelectionSet(kLFLen, 1+kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #17 (kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first <div> element");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #17 (kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.lastChild,
+     "runSetSelectionEventTest #17 (kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the second <div> element");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #17 (kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(kLFLen, "a" + kLF, "runSetSelectionEventTest #17 (kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  await synthesizeSelectionSet(1+2*kLFLen, 0);
+  is(selection.anchorNode, contenteditable.lastChild,
+     "runSetSelectionEventTest #17 (1+2*kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor node should be the second <div> element");
+  is(selection.anchorOffset, 0,
+     "runSetSelectionEventTest #17 (1+2*kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 0");
+  is(selection.focusNode, contenteditable.lastChild,
+     "runSetSelectionEventTest #17 (1+2*kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus node should be the second <div> element");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #17 (1+2*kLFLen, 0), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(1+2*kLFLen, "", "runSetSelectionEventTest #17 (1+2*kLFLen, 0), \"" + contenteditable.innerHTML + "\"");
+
+  // #18 (bug 1319660 - content iterator start node regression)
+  contenteditable.innerHTML = "<div><br></div><div><br></div>";
+
+  await synthesizeSelectionSet(2*kLFLen, kLFLen);
+  is(selection.anchorNode, contenteditable.firstChild,
+     "runSetSelectionEventTest #18 (2*kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor node should be the first <div> element");
+  is(selection.anchorOffset, 1,
+     "runSetSelectionEventTest #18 (2*kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection anchor offset should be 1");
+  is(selection.focusNode, contenteditable.lastChild,
+     "runSetSelectionEventTest #18 (2*kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus node should be the second <div> element");
+  is(selection.focusOffset, 0,
+     "runSetSelectionEventTest #18 (2*kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\": selection focus offset should be 0");
+  checkSelection(2*kLFLen, kLF, "runSetSelectionEventTest #18 (2*kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+}
+
+function runQueryTextContentEventTest()
+{
+  contenteditable.focus();
+
+  let result;
+
+  // #1
+  contenteditable.innerHTML = "abc<br>def";
+
+  result = synthesizeQueryTextContent(0, 6 + kLFLen);
+  is(result.text, "abc" + kLF + "def", "runQueryTextContentEventTest #1 (0, 6+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, 100);
+  is(result.text, "abc" + kLF + "def", "runQueryTextContentEventTest #1 (0, 100), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(2, 2 + kLFLen);
+  is(result.text, "c" + kLF + "d", "runQueryTextContentEventTest #1 (2, 2+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(1, 2);
+  is(result.text, "bc", "runQueryTextContentEventTest #1 (1, 2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(3, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #1 (3, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(6 + kLFLen, 1);
+  is(result.text, "", "runQueryTextContentEventTest #1 (6 + kLFLen, 0), \"" + contenteditable.innerHTML + "\"");
+
+  // #2
+  contenteditable.innerHTML = "<p>a<b>b</b>c</p><p>def</p>";
+
+  result = synthesizeQueryTextContent(kLFLen, 4+kLFLen);
+  is(result.text, "abc" + kLF + "d", "runQueryTextContentEventTest #2 (kLFLen, 4+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(kLFLen, 2);
+  is(result.text, "ab", "runQueryTextContentEventTest #2 (kLFLen, 2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(1+kLFLen, 2);
+  is(result.text, "bc", "runQueryTextContentEventTest #2 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(2+kLFLen, 2+kLFLen);
+  is(result.text, "c" + kLF + "d", "runQueryTextContentEventTest #2 (2+kLFLen, 2+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(3+kLFLen*2, 1);
+  is(result.text, "d", "runQueryTextContentEventTest #2 (3+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #2 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(2+kLFLen, 1+kLFLen);
+  is(result.text, "c" + kLF, "runQueryTextContentEventTest #2 (2+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(3+kLFLen, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #2 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(3+kLFLen, 1+kLFLen);
+  is(result.text, kLF + "d", "runQueryTextContentEventTest #2 (3+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  // #3
+  contenteditable.innerHTML = "<div>abc<p>def</p></div>";
+
+  result = synthesizeQueryTextContent(1+kLFLen, 2);
+  is(result.text, "bc", "runQueryTextContentEventTest #3 (1+kLFLen, 2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(1+kLFLen, 3+kLFLen);
+  is(result.text, "bc" + kLF + "d", "runQueryTextContentEventTest #3 (1+kLFLen, 3+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(3+kLFLen*2, 1);
+  is(result.text, "d", "runQueryTextContentEventTest #3 (3+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, 6+kLFLen*2);
+  is(result.text, kLF + "abc" + kLF + "def", "runQueryTextContentEventTest #3 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, 100);
+  is(result.text, kLF + "abc" + kLF + "def", "runQueryTextContentEventTest #3 (0, 100), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(4+kLFLen*2, 2);
+  is(result.text, "ef", "runQueryTextContentEventTest #3 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(4+kLFLen*2, 100);
+  is(result.text, "ef", "runQueryTextContentEventTest #3 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(6+kLFLen*2, 1);
+  is(result.text, "", "runQueryTextContentEventTest #3 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #3 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, 1+kLFLen);
+  is(result.text, kLF + "a", "runQueryTextContentEventTest #3 (0, 1+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(2+kLFLen, 1+kLFLen);
+  is(result.text, "c" + kLF, "runQueryTextContentEventTest #3 (2+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(3+kLFLen, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #3 (3+kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(3+kLFLen, 1+kLFLen);
+  is(result.text, kLF + "d", "runQueryTextContentEventTest #3 (3+kLFLen, 1+kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  // #4
+  contenteditable.innerHTML = "<div><p>abc</p>def</div>";
+
+  result = synthesizeQueryTextContent(1+kLFLen*2, 2);
+  is(result.text, "bc", "runQueryTextContentEventTest #4 (1+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(1+kLFLen*2, 3);
+  is(result.text, "bcd", "runQueryTextContentEventTest #4 (1+kLFLen*2, 3), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(3+kLFLen*2, 1);
+  is(result.text, "d", "runQueryTextContentEventTest #4 (3+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, 6+kLFLen*2);
+  is(result.text, kLF + kLF + "abcdef", "runQueryTextContentEventTest #4 (0, 6+kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, 100);
+  is(result.text, kLF + kLF + "abcdef", "runQueryTextContentEventTest #4 (0, 100), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(4+kLFLen*2, 2);
+  is(result.text, "ef", "runQueryTextContentEventTest #4 (4+kLFLen*2, 2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(4+kLFLen*2, 100);
+  is(result.text, "ef", "runQueryTextContentEventTest #4 (4+kLFLen*2, 100), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(6+kLFLen*2, 1);
+  is(result.text, "", "runQueryTextContentEventTest #4 (6+kLFLen*2, 1), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #4 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, kLFLen*2);
+  is(result.text, kLF + kLF, "runQueryTextContentEventTest #4 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, 1+kLFLen*2);
+  is(result.text, kLF + kLF + "a", "runQueryTextContentEventTest #4 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(kLFLen, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #4 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(kLFLen, 1+kLFLen);
+  is(result.text, kLF + "a", "runQueryTextContentEventTest #4 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  // #5
+  contenteditable.innerHTML = "<br>";
+
+  result = synthesizeQueryTextContent(0, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #5 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(kLFLen, 1);
+  is(result.text, "", "runQueryTextContentEventTest #5 (kLFLen, 1), \"" + contenteditable.innerHTML + "\"");
+
+  // #6
+  contenteditable.innerHTML = "<p><br></p>";
+
+  result = synthesizeQueryTextContent(kLFLen, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #6 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(kLFLen*2, 1);
+  is(result.text, "", "runQueryTextContentEventTest #5 (kLFLen*2, 1), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #6 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, kLFLen*2);
+  is(result.text, kLF + kLF, "runQueryTextContentEventTest #6 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  // #7
+  contenteditable.innerHTML = "<br><br>";
+
+  result = synthesizeQueryTextContent(0, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #7 (0, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(0, kLFLen * 2);
+  is(result.text, kLF + kLF, "runQueryTextContentEventTest #7 (0, kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(kLFLen, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #7 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(kLFLen * 2, 1);
+  is(result.text, "", "runQueryTextContentEventTest #7 (kLFLen*2, 1), \"" + contenteditable.innerHTML + "\"");
+
+  // #8
+  contenteditable.innerHTML = "<p><br><br></p>";
+
+  result = synthesizeQueryTextContent(kLFLen, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #8 (kLFLen, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(kLFLen, kLFLen * 2);
+  is(result.text, kLF + kLF, "runQueryTextContentEventTest #8 (kLFLen, kLFLen*2), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(kLFLen*2, kLFLen);
+  is(result.text, kLF, "runQueryTextContentEventTest #8 (kLFLen*2, kLFLen), \"" + contenteditable.innerHTML + "\"");
+
+  result = synthesizeQueryTextContent(kLFLen*3, 1);
+  is(result.text, "", "runQueryTextContentEventTest #8 (kLFLen*3, 1), \"" + contenteditable.innerHTML + "\"");
+
+  // #16
+  contenteditable.innerHTML = "a<blink>b</blink>c";
+
+  result = synthesizeQueryTextContent(0, 3);
+  is(result.text, "abc", "runQueryTextContentEventTest #16 (0, 3), \"" + contenteditable.innerHTML + "\"");
+}
+
+function runQuerySelectionEventTest()
+{
+  contenteditable.focus();
+
+  let selection = windowOfContenteditable.getSelection();
+
+  // #1
+  contenteditable.innerHTML = "<br/>a";
+  selection.setBaseAndExtent(
+    contenteditable.firstChild,
+    0,
+    contenteditable.lastChild,
+    1
+  );
+  checkSelection(
+    0,
+    `${kLF}a`,
+    `runQuerySelectionEventTest #1, "${contenteditable.innerHTML}"`
+  );
+
+  // #2
+  contenteditable.innerHTML = "<p></p><p>abc</p>";
+  selection.setBaseAndExtent(
+    contenteditable.firstChild,
+    0,
+    contenteditable.lastChild.firstChild,
+    1
+  );
+  checkSelection(
+    kLFLen,
+    `${kLF}a`,
+    `runQuerySelectionEventTest #2, "${contenteditable.innerHTML}"`
+  );
+
+  // #3
+  contenteditable.innerHTML = "<p>abc</p><p>def</p>";
+  selection.setBaseAndExtent(
+    contenteditable.firstChild,
+    0,
+    contenteditable.lastChild.firstChild,
+    1
+  );
+  checkSelection(
+    kLFLen,
+    `abc${kLF}d`,
+    `runQuerySelectionEventTest #3, "${contenteditable.innerHTML}"`
+  );
+
+  // #4
+  contenteditable.innerHTML = "<p>abc</p>";
+  selection.removeAllRanges();
+  checkSelection(
+    null,
+    null,
+    `runQuerySelectionEventTest #4, "${contenteditable.innerHTML}"`
+  );
+}
+
+function runQueryIMESelectionTest()
+{
+  textarea.focus();
+  textarea.value = "before  after";
+  let startoffset = textarea.selectionStart = textarea.selectionEnd = "before ".length;
+
+  if (!checkIMESelection("RawClause", false, 0, "", "runQueryIMESelectionTest: before starting composition") ||
+      !checkIMESelection("SelectedRawClause", false, 0, "", "runQueryIMESelectionTest: before starting composition") ||
+      !checkIMESelection("ConvertedClause", false, 0, "", "runQueryIMESelectionTest: before starting composition") ||
+      !checkIMESelection("SelectedClause", false, 0, "", "runQueryIMESelectionTest: before starting composition")) {
+    synthesizeComposition({ type: "compositioncommitasis" });
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "a",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  if (!checkIMESelection("RawClause", true, startoffset, "a", "runQueryIMESelectionTest: inputting raw text") ||
+      !checkIMESelection("SelectedRawClause", false, 0, "", "runQueryIMESelectionTest: inputting raw text") ||
+      !checkIMESelection("ConvertedClause", false, 0, "", "runQueryIMESelectionTest: inputting raw text") ||
+      !checkIMESelection("SelectedClause", false, 0, "", "runQueryIMESelectionTest: inputting raw text")) {
+    synthesizeComposition({ type: "compositioncommitasis" });
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "abcdefgh",
+        "clauses":
+        [
+          { "length": 8, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 8, "length": 0 }
+    });
+
+  if (!checkIMESelection("RawClause", true, startoffset, "abcdefgh", "runQueryIMESelectionTest: updating raw text") ||
+      !checkIMESelection("SelectedRawClause", false, 0, "", "runQueryIMESelectionTest: updating raw text") ||
+      !checkIMESelection("ConvertedClause", false, 0, "", "runQueryIMESelectionTest: updating raw text") ||
+      !checkIMESelection("SelectedClause", false, 0, "", "runQueryIMESelectionTest: updating raw text")) {
+    synthesizeComposition({ type: "compositioncommitasis" });
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "ABCDEFGH",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+          { "length": 3, "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE },
+          { "length": 3, "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE },
+        ]
+      },
+      "caret": { "start": 2, "length": 0 }
+    });
+
+  if (!checkIMESelection("RawClause", false, 0, "", "runQueryIMESelectionTest: starting to convert") ||
+      !checkIMESelection("SelectedRawClause", false, 0, "", "runQueryIMESelectionTest: starting to convert") ||
+      !checkIMESelection("ConvertedClause", true, startoffset + 2, "CDE", "runQueryIMESelectionTest: starting to convert") ||
+      !checkIMESelection("SelectedClause", true, startoffset, "AB", "runQueryIMESelectionTest: starting to convert")) {
+    synthesizeComposition({ type: "compositioncommitasis" });
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "ABCDEFGH",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE },
+          { "length": 3, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+          { "length": 3, "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE },
+        ]
+      },
+      "caret": { "start": 5, "length": 0 }
+    });
+
+  if (!checkIMESelection("RawClause", false, 0, "", "runQueryIMESelectionTest: changing selected clause") ||
+      !checkIMESelection("SelectedRawClause", false, 0, "", "runQueryIMESelectionTest: changing selected clause") ||
+      !checkIMESelection("ConvertedClause", true, startoffset, "AB", "runQueryIMESelectionTest: changing selected clause") ||
+      !checkIMESelection("SelectedClause", true, startoffset + 2, "CDE", "runQueryIMESelectionTest: changing selected clause")) {
+    synthesizeComposition({ type: "compositioncommitasis" });
+    return;
+  }
+
+  synthesizeComposition({ type: "compositioncommitasis" });
+
+  if (!checkIMESelection("RawClause", false, 0, "", "runQueryIMESelectionTest: after committing composition") ||
+      !checkIMESelection("SelectedRawClause", false, 0, "", "runQueryIMESelectionTest: after committing composition") ||
+      !checkIMESelection("ConvertedClause", false, 0, "", "runQueryIMESelectionTest: after committing composition") ||
+      !checkIMESelection("SelectedClause", false, 0, "", "runQueryIMESelectionTest: after committing composition")) {
+    return;
+  }
+
+  startoffset = textarea.selectionStart;
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "abcdefgh",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE },
+          { "length": 1, "attr": COMPOSITION_ATTR_SELECTED_RAW_CLAUSE },
+          { "length": 1, "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE },
+          { "length": 1, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE },
+          { "length": 1, "attr": COMPOSITION_ATTR_SELECTED_RAW_CLAUSE },
+          { "length": 1, "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE },
+          { "length": 1, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+        ]
+      },
+      "caret": { "start": 8, "length": 0 }
+    });
+
+  if (!checkIMESelection("RawClause", true, startoffset, "a", "runQueryIMESelectionTest: unrealistic testcase") ||
+      !checkIMESelection("SelectedRawClause", true, startoffset + 1, "b", "runQueryIMESelectionTest: unrealistic testcase") ||
+      !checkIMESelection("ConvertedClause", true, startoffset + 2, "c", "runQueryIMESelectionTest: unrealistic testcase") ||
+      !checkIMESelection("SelectedClause", true, startoffset + 3, "d", "runQueryIMESelectionTest: unrealistic testcase")) {
+    synthesizeComposition({ type: "compositioncommitasis" });
+    return;
+  }
+
+  synthesizeComposition({ type: "compositioncommitasis" });
+}
+
+function runQueryPasswordTest() {
+  function checkRange(aOffset, aLength, aExpectedResult, aDescription) {
+    password.focus();
+    let result = synthesizeQueryTextContent(aOffset, aLength);
+    is(result.text, aExpectedResult,
+       `${aDescription}: synthesizeQueryTextContent(${aOffset}, ${aLength})`);
+    password.setSelectionRange(aOffset, aOffset + aLength);
+    result = synthesizeQuerySelectedText();
+    is(result.text, aExpectedResult,
+       `${aDescription}: synthesizeQuerySelectedText(${aOffset}, ${aLength})`);
+  }
+
+  let editor = password.editor;
+  const kMask = editor.passwordMask;
+  password.value = "abcdef";
+
+  editor.mask();
+  checkRange(0, 6, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: unmasked range is not specified #1");
+  checkRange(0, 3, `${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: unmasked range is not specified #2");
+  checkRange(3, 3, `${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: unmasked range is not specified #3");
+  checkRange(2, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: unmasked range is not specified #4");
+
+  editor.unmask(0, 6);
+  checkRange(0, 6, "abcdef",
+             "runQueryPasswordTest: unmasked range 0-6 #1");
+  checkRange(0, 3, "abc",
+             "runQueryPasswordTest: unmasked range 0-6 #2");
+  checkRange(3, 3, "def",
+             "runQueryPasswordTest: unmasked range 0-6 #3");
+  checkRange(2, 2, "cd",
+             "runQueryPasswordTest: unmasked range 0-6 #4");
+
+  editor.unmask(0, 3);
+  checkRange(0, 6, `abc${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: unmasked range 0-3 #1");
+  checkRange(0, 3, "abc",
+             "runQueryPasswordTest: unmasked range 0-3 #2");
+  checkRange(3, 3, `${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: unmasked range 0-3 #3");
+  checkRange(2, 2, `c${kMask}`,
+             "runQueryPasswordTest: unmasked range 0-3 #4");
+
+  editor.unmask(3, 6);
+  checkRange(0, 6, `${kMask}${kMask}${kMask}def`,
+             "runQueryPasswordTest: unmasked range 3-6 #1");
+  checkRange(0, 3, `${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: unmasked range 3-6 #2");
+  checkRange(3, 3, `def`,
+             "runQueryPasswordTest: unmasked range 3-6 #3");
+  checkRange(2, 2, `${kMask}d`,
+             "runQueryPasswordTest: unmasked range 3-6 #4");
+
+  editor.unmask(2, 4);
+  checkRange(0, 6, `${kMask}${kMask}cd${kMask}${kMask}`,
+             "runQueryPasswordTest: unmasked range 3-4 #1");
+  checkRange(1, 2, `${kMask}c`,
+             "runQueryPasswordTest: unmasked range 3-4 #2");
+  checkRange(1, 3, `${kMask}cd`,
+             "runQueryPasswordTest: unmasked range 3-4 #3");
+  checkRange(1, 4, `${kMask}cd${kMask}`,
+             "runQueryPasswordTest: unmasked range 3-4 #4");
+  checkRange(2, 2, "cd",
+             "runQueryPasswordTest: unmasked range 3-4 #5");
+  checkRange(2, 3, `cd${kMask}`,
+             "runQueryPasswordTest: unmasked range 3-4 #6");
+
+
+  const kEmoji = String.fromCodePoint(0x1f914);
+  password.value = `${kEmoji}${kEmoji}${kEmoji}`
+
+  editor.mask();
+  checkRange(0, 6, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range is not specified");
+
+  editor.unmask(0, 2);
+  checkRange(0, 6, `${kEmoji}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 0-2 #1");
+  checkRange(0, 2, `${kEmoji}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 0-2 #2");
+  checkRange(2, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 0-2 #3");
+  checkRange(4, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 0-2 #4");
+
+  editor.unmask(2, 4);
+  checkRange(0, 6, `${kMask}${kMask}${kEmoji}${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 2-4 #1");
+  checkRange(0, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 2-4 #2");
+  checkRange(2, 2, `${kEmoji}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 2-4 #3");
+  checkRange(4, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 2-4 #4");
+
+  editor.unmask(4, 6);
+  checkRange(0, 6, `${kMask}${kMask}${kMask}${kMask}${kEmoji}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 4-6 #1");
+  checkRange(0, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 4-6 #2");
+  checkRange(2, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 4-6 #3");
+  checkRange(4, 2, `${kEmoji}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 4-6 #4");
+
+  editor.unmask(0, 1);
+  checkRange(0, 6, `${kEmoji}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 0-1");
+
+  editor.unmask(1, 2);
+  checkRange(0, 6, `${kEmoji}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 1-2");
+
+  editor.unmask(2, 3);
+  checkRange(0, 6, `${kMask}${kMask}${kEmoji}${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 2-3");
+
+  editor.unmask(3, 4);
+  checkRange(0, 6, `${kMask}${kMask}${kEmoji}${kMask}${kMask}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 3-4");
+
+  editor.unmask(4, 5);
+  checkRange(0, 6, `${kMask}${kMask}${kMask}${kMask}${kEmoji}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 4-5");
+
+  editor.unmask(5, 6);
+  checkRange(0, 6, `${kMask}${kMask}${kMask}${kMask}${kEmoji}`,
+             "runQueryPasswordTest: Emojis in password, unmasked range 5-6");
+
+
+  const kEmojiSuperhero = String.fromCodePoint(0x1f9b8);
+  const kEmojiMediumSkinTone = String.fromCodePoint(0x1f3fd);
+  const kZeroWidthJoiner = "\u200d";
+  const kFemaleSign = "\u2640";
+  const kVariationSelector16 = "\ufe0f";
+  const kComplicatedEmoji = `${kEmojiSuperhero}${kEmojiMediumSkinTone}${kZeroWidthJoiner}${kFemaleSign}${kVariationSelector16}`;
+  password.value = `${kComplicatedEmoji}${kComplicatedEmoji}${kComplicatedEmoji}`
+  editor.mask();
+  checkRange(0, 21, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range is not specified");
+
+  editor.unmask(0, 7);
+  checkRange(0, 21, `${kComplicatedEmoji}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 0-7 #1");
+  checkRange(0, 7, `${kComplicatedEmoji}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 0-7 #2");
+  checkRange(7, 7, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 0-7 #3");
+  checkRange(14, 7, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 0-7 #4");
+
+  editor.unmask(7, 14);
+  checkRange(0, 21, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kComplicatedEmoji}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 7-14 #1");
+  checkRange(0, 7, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 7-14 #2");
+  checkRange(7, 7, `${kComplicatedEmoji}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 7-14 #3");
+  checkRange(14, 7, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 7-14 #4");
+
+  editor.unmask(14, 21);
+  checkRange(0, 21, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kComplicatedEmoji}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 14-21 #1");
+  checkRange(0, 7, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 14-21 #2");
+  checkRange(7, 7, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 14-21 #3");
+  checkRange(14, 7, `${kComplicatedEmoji}`,
+             "runQueryPasswordTest: Complicated emojis in password, unmasked range 14-21 #4");
+
+  password.value = `${kComplicatedEmoji}`
+  editor.unmask(0, 1);
+  checkRange(0, 7, `${kEmojiSuperhero}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emoji in password, unmasked range 0-1");
+
+  editor.unmask(1, 2);
+  checkRange(0, 7, `${kEmojiSuperhero}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emoji in password, unmasked range 1-2");
+
+  editor.unmask(2, 3);
+  checkRange(0, 7, `${kMask}${kMask}${kEmojiMediumSkinTone}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emoji in password, unmasked range 2-3");
+
+  editor.unmask(3, 4);
+  checkRange(0, 7, `${kMask}${kMask}${kEmojiMediumSkinTone}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emoji in password, unmasked range 3-4");
+
+  editor.unmask(4, 5);
+  checkRange(0, 7, `${kMask}${kMask}${kMask}${kMask}${kZeroWidthJoiner}${kMask}${kMask}`,
+             "runQueryPasswordTest: Complicated emoji in password, unmasked range 4-5");
+
+  editor.unmask(5, 6);
+  checkRange(0, 7, `${kMask}${kMask}${kMask}${kMask}${kMask}${kFemaleSign}${kMask}`,
+             "runQueryPasswordTest: Complicated emoji in password, unmasked range 5-6");
+
+  editor.unmask(6, 7);
+  checkRange(0, 7, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kVariationSelector16}`,
+             "runQueryPasswordTest: Complicated emoji in password, unmasked range 6-7");
+
+
+  const kKanji = "\u8fba";
+  const kIVS = String.fromCodePoint(0xe0101);
+  const kKanjiWithIVS = `${kKanji}${kIVS}`;
+  password.value = `${kKanjiWithIVS}${kKanjiWithIVS}${kKanjiWithIVS}`
+
+  editor.mask();
+  checkRange(0, 9, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range is not specified");
+
+  editor.unmask(0, 3);
+  checkRange(0, 9, `${kKanjiWithIVS}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #1");
+  checkRange(0, 3, `${kKanjiWithIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #2");
+  checkRange(1, 3, `${kIVS}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #3");
+  checkRange(0, 1, `${kKanji}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #4");
+  checkRange(1, 2, `${kIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #5");
+  checkRange(3, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #6");
+  checkRange(4, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #7");
+  checkRange(6, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #8");
+  checkRange(7, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #9");
+
+  editor.unmask(0, 1);
+  checkRange(0, 9, `${kKanji}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 0-1 #1");
+  checkRange(0, 1, `${kKanji}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 0-1 #2");
+  checkRange(1, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 0-1 #3");
+  checkRange(3, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 0-1 #4");
+  checkRange(4, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 0-1 #5");
+  checkRange(6, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 0-1 #6");
+  checkRange(7, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 0-1 #7");
+
+  editor.unmask(1, 3);
+  checkRange(0, 9, `${kMask}${kIVS}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #1");
+  checkRange(0, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #2");
+  checkRange(1, 2, `${kIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #3");
+  checkRange(3, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #4");
+  checkRange(4, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #5");
+  checkRange(6, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #6");
+  checkRange(7, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-3 #7");
+
+  editor.unmask(3, 6);
+  checkRange(0, 9, `${kMask}${kMask}${kMask}${kKanjiWithIVS}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-6 #1");
+  checkRange(3, 3, `${kKanjiWithIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-6 #2");
+  checkRange(4, 3, `${kIVS}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-6 #3");
+  checkRange(0, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-6 #4");
+  checkRange(1, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-6 #5");
+  checkRange(3, 1, `${kKanji}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-6 #6");
+  checkRange(4, 2, `${kIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-6 #7");
+  checkRange(6, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-6 #8");
+  checkRange(7, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-6 #9");
+
+  editor.unmask(3, 4);
+  checkRange(0, 9, `${kMask}${kMask}${kMask}${kKanji}${kMask}${kMask}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-4 #1");
+  checkRange(0, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-4 #2");
+  checkRange(1, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-4 #3");
+  checkRange(3, 1, `${kKanji}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-4 #4");
+  checkRange(4, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-4 #5");
+  checkRange(6, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-4 #6");
+  checkRange(7, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-4 #7");
+
+  editor.unmask(4, 6);
+  checkRange(0, 9, `${kMask}${kMask}${kMask}${kMask}${kIVS}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 4-6 #1");
+  checkRange(0, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 4-6 #2");
+  checkRange(1, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 4-6 #3");
+  checkRange(3, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 4-6 #4");
+  checkRange(4, 2, `${kIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 4-6 #5");
+  checkRange(6, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 4-6 #6");
+  checkRange(7, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 4-6 #7");
+
+  editor.unmask(6, 9);
+  checkRange(0, 9, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kKanjiWithIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-9 #1");
+  checkRange(6, 3, `${kKanjiWithIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-9 #2");
+  checkRange(4, 3, `${kMask}${kMask}${kKanji}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-9 #3");
+  checkRange(0, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-9 #4");
+  checkRange(1, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-9 #5");
+  checkRange(3, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-9 #6");
+  checkRange(4, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-9 #7");
+  checkRange(6, 1, `${kKanji}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-9 #8");
+  checkRange(7, 2, `${kIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-9 #9");
+
+  editor.unmask(6, 7);
+  checkRange(0, 9, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kKanji}${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-7 #1");
+  checkRange(0, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-7 #2");
+  checkRange(1, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-7 #3");
+  checkRange(3, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-7 #4");
+  checkRange(4, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-7 #5");
+  checkRange(6, 1, `${kKanji}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-7 #6");
+  checkRange(7, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 6-7 #7");
+
+  editor.unmask(7, 9);
+  checkRange(0, 9, `${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kMask}${kIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 7-9 #1");
+  checkRange(0, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 7-9 #2");
+  checkRange(1, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 7-9 #3");
+  checkRange(3, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 7-9 #4");
+  checkRange(4, 2, `${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 7-9 #5");
+  checkRange(6, 1, `${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 7-9 #6");
+  checkRange(7, 2, `${kIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 7-9 #7");
+
+  password.value = `${kKanjiWithIVS}${kKanjiWithIVS}`;
+  editor.unmask(0, 2);
+  checkRange(0, 6, `${kKanjiWithIVS}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 0-2");
+
+  editor.unmask(1, 2);
+  checkRange(0, 6, `${kMask}${kIVS}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 1-2");
+
+  editor.unmask(2, 3);
+  checkRange(0, 6, `${kMask}${kIVS}${kMask}${kMask}${kMask}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 2-3");
+
+  editor.unmask(3, 5);
+  checkRange(0, 6, `${kMask}${kMask}${kMask}${kKanjiWithIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 3-5");
+
+  editor.unmask(4, 5);
+  checkRange(0, 6, `${kMask}${kMask}${kMask}${kMask}${kIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 4-5");
+
+  editor.unmask(5, 6);
+  checkRange(0, 6, `${kMask}${kMask}${kMask}${kMask}${kIVS}`,
+             "runQueryPasswordTest: Pairs of Kanji and IVS in password, unmasked range 5-6");
+
+  editor.mask();
+}
+
+function runQueryContentEventRelativeToInsertionPoint()
+{
+  textarea.focus();
+  textarea.value = "0123456789";
+
+  // "[]0123456789"
+  let startOffset = textarea.selectionStart = textarea.selectionEnd = 0;
+  if (!checkContentRelativeToSelection(0, 1, 0, "0", "runQueryContentEventRelativeToInsertionPoint[0-0]", "#1") ||
+      !checkContentRelativeToSelection(-1, 1, 0, "0", "runQueryContentEventRelativeToInsertionPoint[0-0]", "#2") ||
+      !checkContentRelativeToSelection(1, 1, 1, "1", "runQueryContentEventRelativeToInsertionPoint[0-0]", "#3") ||
+      !checkContentRelativeToSelection(5, 10, 5, "56789", "runQueryContentEventRelativeToInsertionPoint[0-0]", "#4") ||
+      !checkContentRelativeToSelection(10, 1, 10, "", "runQueryContentEventRelativeToInsertionPoint[0-0]", "#5")) {
+    return;
+  }
+
+  // "[01234]56789"
+  textarea.selectionEnd = 5;
+  if (!checkContentRelativeToSelection(0, 1, 0, "0", "runQueryContentEventRelativeToInsertionPoint[0-5]", "#1") ||
+      !checkContentRelativeToSelection(-1, 1, 0, "0", "runQueryContentEventRelativeToInsertionPoint[0-5]", "#2") ||
+      !checkContentRelativeToSelection(1, 1, 1, "1", "runQueryContentEventRelativeToInsertionPoint[0-5]", "#3") ||
+      !checkContentRelativeToSelection(5, 10, 5, "56789", "runQueryContentEventRelativeToInsertionPoint[0-5]", "#4") ||
+      !checkContentRelativeToSelection(10, 1, 10, "", "runQueryContentEventRelativeToInsertionPoint[0-5]", "#5")) {
+    return;
+  }
+
+  // "0123[]456789"
+  startOffset = textarea.selectionStart = textarea.selectionEnd = 4;
+  if (!checkContentRelativeToSelection(0, 1, startOffset + 0, "4", "runQueryContentEventRelativeToInsertionPoint[4-4]", "#1") ||
+      !checkContentRelativeToSelection(-1, 1, startOffset - 1, "3", "runQueryContentEventRelativeToInsertionPoint[4-4]", "#2") ||
+      !checkContentRelativeToSelection(1, 1, startOffset + 1, "5", "runQueryContentEventRelativeToInsertionPoint[4-4]", "#3") ||
+      !checkContentRelativeToSelection(5, 10, startOffset + 5, "9", "runQueryContentEventRelativeToInsertionPoint[4-4]", "#4") ||
+      !checkContentRelativeToSelection(10, 1, 10, "", "runQueryContentEventRelativeToInsertionPoint[4-4]", "#5")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "a",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+  // "0123[a]456789"
+  if (!checkContentRelativeToSelection(0, 1, startOffset + 0, "a", "runQueryContentEventRelativeToInsertionPoint[composition at 4]", "#1") ||
+      !checkContentRelativeToSelection(-1, 1, startOffset - 1, "3", "runQueryContentEventRelativeToInsertionPoint[composition at 4]", "#2") ||
+      !checkContentRelativeToSelection(1, 1, startOffset + 1, "4", "runQueryContentEventRelativeToInsertionPoint[composition at 4]", "#3") ||
+      !checkContentRelativeToSelection(5, 10, startOffset + 5, "89", "runQueryContentEventRelativeToInsertionPoint[composition at 4]", "#4") ||
+      !checkContentRelativeToSelection(11, 1, 11, "", "runQueryContentEventRelativeToInsertionPoint[composition at 4]")) {
+    synthesizeComposition({ type: "compositioncommitasis" });
+    return;
+  }
+
+  synthesizeComposition({ type: "compositioncommitasis" });
+
+  // Move start of composition at first compositionupdate event.
+  function onCompositionUpdate(aEvent)
+  {
+    startOffset = textarea.selectionStart = textarea.selectionEnd = textarea.selectionStart - 1;
+    textarea.removeEventListener("compositionupdate", onCompositionUpdate);
+  }
+  textarea.addEventListener("compositionupdate", onCompositionUpdate);
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "b",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+  // "0123[b]a456789"
+  if (!checkContentRelativeToSelection(0, 1, startOffset + 0, "b", "runQueryContentEventRelativeToInsertionPoint[composition at 3]", "#1") ||
+      !checkContentRelativeToSelection(-1, 1, startOffset - 1, "3", "runQueryContentEventRelativeToInsertionPoint[composition at 3]", "#2") ||
+      !checkContentRelativeToSelection(1, 1, startOffset + 1, "a", "runQueryContentEventRelativeToInsertionPoint[composition at 3]", "#3") ||
+      !checkContentRelativeToSelection(5, 10, startOffset + 5, "789", "runQueryContentEventRelativeToInsertionPoint[composition at 3]", "#4") ||
+      !checkContentRelativeToSelection(12, 1, 12, "", "runQueryContentEventRelativeToInsertionPoint[composition at 3]", "#5")) {
+    synthesizeComposition({ type: "compositioncommitasis" });
+    return;
+  }
+
+  synthesizeComposition({ type: "compositioncommitasis" });
+}
+
+function runBug1375825Test()
+{
+  contenteditable.focus();
+
+  // #1
+  contenteditable.innerHTML = "abc<span contenteditable=\"false\">defgh</span>";
+
+  let ret = synthesizeQueryTextRect(2, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #1 (2, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "c", "runBug1375825Test #1 (2, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'c'");
+
+  ret = synthesizeQueryTextRect(3, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #1 (3, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "d", "runBug1375825Test #1 (3, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'd'");
+
+  ret = synthesizeQueryTextRect(4, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #1 (4, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "e", "runBug1375825Test #1 (4, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'e'");
+
+  ret = synthesizeQueryTextRect(5, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #1 (5, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "f", "runBug1375825Test #1 (5, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'f'");
+
+  ret = synthesizeQueryTextRect(6, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #1 (6, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "g", "runBug1375825Test #1 (6, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'g'");
+
+  ret = synthesizeQueryTextRect(7, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #1 (7, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "h", "runBug1375825Test #1 (7, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'h'");
+
+  // #2
+  contenteditable.innerHTML = "abc<span style=\"user-select: all;\">defgh</span>";
+
+  ret = synthesizeQueryTextRect(2, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #2 (2, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "c", "runBug1375825Test #2 (2, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'c'");
+
+  ret = synthesizeQueryTextRect(3, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #2 (3, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "d", "runBug1375825Test #2 (3, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'd'");
+
+  ret = synthesizeQueryTextRect(4, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #2 (4, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "e", "runBug1375825Test #2 (4, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'e'");
+
+  ret = synthesizeQueryTextRect(5, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #2 (5, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "f", "runBug1375825Test #2 (5, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'f'");
+
+  ret = synthesizeQueryTextRect(6, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #2 (6, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "g", "runBug1375825Test #2 (6, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'g'");
+
+  ret = synthesizeQueryTextRect(7, 1);
+  if (!checkQueryContentResult(ret, "runBug1375825Test #2 (7, 1), \"" + contenteditable.innerHTML + "\"")) {
+    return;
+  }
+  is(ret.text, "h", "runBug1375825Test #2 (7, 1), \"" + contenteditable.innerHTML + "\": should have queried a rect for 'h'");
+}
+
+function runBug1530649Test()
+{
+  // Vietnamese IME on macOS commits composition with typing space key.
+  // Then, typing new word shouldn't trim the trailing whitespace.
+  contenteditable.focus();
+  contenteditable.innerHTML = "";
+  synthesizeCompositionChange(
+    {composition: {string: "abc", clauses: [{length: 3, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+     caret: {start: 3, length: 0}});
+  synthesizeComposition({type: "compositioncommit", data: "abc ", key: " "});
+
+  is(contenteditable.innerHTML, "abc <br>",
+     "runBug1530649Test: The trailing space shouldn't be removed");
+
+  synthesizeCompositionChange(
+    {composition: {string: "d", clauses: [{length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+     caret: {start: 1, length: 0}});
+
+  is(contenteditable.innerHTML, "abc d<br>",
+     "runBug1530649Test: The new composition string shouldn't remove the last space");
+
+  synthesizeComposition({type: "compositioncommitasis", key: "KEY_Enter"});
+
+  is(contenteditable.innerHTML, "abc d<br>",
+     "runBug1530649Test: Committing the new composition string shouldn't remove the last space");
+}
+
+function runBug1571375Test()
+{
+  let selection = windowOfContenteditableBySpan.getSelection();
+  let doc = document.getElementById("iframe7").contentDocument;
+
+  contenteditableBySpan.focus();
+
+  contenteditableBySpan.innerHTML = "hello world";
+  let range = doc.createRange();
+  range.setStart(contenteditableBySpan.firstChild, 6);
+  range.setEnd(contenteditableBySpan.firstChild, 11);
+  selection.removeAllRanges();
+  selection.addRange(range);
+
+  synthesizeCompositionChange({
+    composition: {string: "world", clauses: [{length: 5, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+    caret: { start: 5, length: 0 },
+  });
+  synthesizeComposition({type: "compositioncommit", data: "world", key: " "});
+  is(contenteditableBySpan.innerHTML, "hello world",
+     "runBug1571375Test: space must not be removed by commit");
+
+  contenteditableBySpan.innerHTML = "hello world";
+  range = doc.createRange();
+  range.setStart(contenteditableBySpan.firstChild, 0);
+  range.setEnd(contenteditableBySpan.firstChild, 5);
+  selection.removeAllRanges();
+  selection.addRange(range);
+
+  synthesizeCompositionChange({
+    composition: {string: "hello", clauses: [{length: 5, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+    caret: { start: 5, length: 0 },
+  });
+  synthesizeComposition({type: "compositioncommit", data: "hello", key: " "});
+  is(contenteditableBySpan.innerHTML, "hello world",
+     "runBug1571375Test: space must not be removed by commit");
+
+  contenteditableBySpan.innerHTML = "hello world<div>.</div>";
+  range = doc.createRange();
+  range.setStart(contenteditableBySpan.firstChild, 6);
+  range.setEnd(contenteditableBySpan.firstChild, 11);
+  selection.removeAllRanges();
+  selection.addRange(range);
+
+  synthesizeCompositionChange({
+    composition: {string: "world", clauses: [{length: 5, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+    caret: {start: 0, length: 0}}
+  );
+  synthesizeComposition({type: "compositioncommit", data: "world", key: " "});
+  is(contenteditableBySpan.innerHTML, "hello world<div>.</div>",
+     "runBug1571375Test: space must not be removed by commit");
+}
+
+async function runBug1584901Test()
+{
+  contenteditableBySpan.focus();
+  contenteditableBySpan.innerHTML = "";
+
+  // XXX synthesizeCompositionChange won't work without wait.
+  await waitForTick();
+
+  synthesizeCompositionChange({
+    composition: {string: "a ", clauses: [{length: 2, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+  });
+  synthesizeComposition({type: "compositioncommitasis", key: " "});
+
+  is(contenteditableBySpan.innerHTML, "a&nbsp;",
+     "runBug1584901Test: space must not be removed by composition change");
+
+  synthesizeCompositionChange({
+    composition: {string: "b ", clauses: [{length: 2, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+  });
+  synthesizeComposition({type: "compositioncommitasis", key: " "});
+
+  is(contenteditableBySpan.innerHTML, "a b&nbsp;",
+     "runBug1584901Test: space must not be removed by composition change");
+}
+
+function runBug1675313Test()
+{
+  input.value = "";
+  input.focus();
+  let count = 0;
+
+  function handler() {
+    input.focus();
+    count++;
+  }
+
+  input.addEventListener("keydown", handler);
+  input.addEventListener("keyup", handler);
+
+  synthesizeCompositionChange({
+    composition: {
+      string: "a",
+      clauses: [{length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE}],
+      key: { key: "a", type: "keyup" },
+    },
+  });
+  synthesizeCompositionChange({
+    composition: {
+      string: "b",
+      clauses: [{length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE}],
+      key: { key: "b", type: "keyup" },
+    },
+  });
+  synthesizeComposition({type: "compositioncommitasis"});
+
+  is(count, 6, "runBug1675313Test: keydown event and keyup event are fired correctly");
+  is(input.value, "b",
+     "runBug1675313Test: re-focus element doesn't commit composition if re-focus isn't click by user");
+
+  input.removeEventListener("keyup", handler);
+}
+
+function runCommitCompositionWithSpaceKey()
+{
+  contenteditable.focus();
+  contenteditable.innerHTML = "";
+
+  // Last white space might be &nbsp; if last child is no <br>
+  // Actually, our implementation will insert <br> element at last child, so
+  // white space will be ASCII space.
+
+  synthesizeCompositionChange({
+    composition: {string: "a", clauses: [{length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+  });
+  synthesizeComposition({type: "compositioncommit", data: "a"});
+  synthesizeKey(" ");
+
+  is(contenteditable.innerHTML, "a <br>",
+     "runCommitCompositionWithSpaceKey: last single space should be kept");
+
+  synthesizeCompositionChange({
+    composition: {string: "b", clauses: [{length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+  });
+  synthesizeComposition({type: "compositioncommit", data: "b"});
+  synthesizeKey(" ");
+
+  is(contenteditable.innerHTML, "a b <br>",
+     "runCommitCompositionWithSpaceKey: inserting composition shouldn't remove last single space.");
+
+  synthesizeCompositionChange({
+    composition: {string: "c", clauses: [{length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+  });
+  synthesizeComposition({type: "compositioncommit", data: "c"});
+  synthesizeKey(" ");
+
+  is(contenteditable.innerHTML, "a b c <br>",
+     "runCommitCompositionWithSpaceKey: inserting composition shouldn't remove last single space.");
+
+  contenteditable.innerHTML = "a";
+  windowOfContenteditable.getSelection().collapse(contenteditable.firstChild, contenteditable.firstChild.length);
+  is(contenteditable.innerHTML, "a",
+     "runCommitCompositionWithSpaceKey: contenteditable should be initialized with text ending with a space and without following <br> element");
+
+  synthesizeCompositionChange({
+    composition: {string: "b", clauses: [{length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+  });
+  synthesizeComposition({type: "compositioncommit", data: "b ", key: { key: " ", code: "Space" }});
+
+  is(contenteditable.innerHTML, "ab <br>",
+     "runCommitCompositionWithSpaceKey: contenteditable should end with a padding <br> element after inserting commit string ending with a space");
+}
+
+function runCSSTransformTest()
+{
+  textarea.focus();
+  textarea.value = "some text";
+  textarea.selectionStart = textarea.selectionEnd = textarea.value.length;
+  let editorRect = synthesizeQueryEditorRect();
+  if (!checkQueryContentResult(editorRect,
+        "runCSSTransformTest: editorRect")) {
+    return;
+  }
+  let firstCharRect = synthesizeQueryTextRect(0, 1);
+  if (!checkQueryContentResult(firstCharRect,
+        "runCSSTransformTest: firstCharRect")) {
+    return;
+  }
+  let lastCharRect = synthesizeQueryTextRect(textarea.value.length - 1, textarea.value.length);
+  if (!checkQueryContentResult(lastCharRect,
+        "runCSSTransformTest: lastCharRect")) {
+    return;
+  }
+  let caretRect = synthesizeQueryCaretRect(textarea.selectionStart);
+  if (!checkQueryContentResult(caretRect,
+        "runCSSTransformTest: caretRect")) {
+    return;
+  }
+  let caretRectBeforeFirstChar = synthesizeQueryCaretRect(0);
+  if (!checkQueryContentResult(caretRectBeforeFirstChar,
+        "runCSSTransformTest: caretRectBeforeFirstChar")) {
+    return;
+  }
+
+  try {
+    textarea.style.transform = "translate(10px, 15px)";
+    function movedRect(aRect, aCSS_CX, aCSS_CY)
+    {
+      return {
+        left: aRect.left + Math.round(aCSS_CX * window.devicePixelRatio),
+        top: aRect.top + Math.round(aCSS_CY * window.devicePixelRatio),
+        width: aRect.width,
+        height: aRect.height
+      };
+    }
+
+    let editorRectTranslated = synthesizeQueryEditorRect();
+    if (!checkQueryContentResult(editorRectTranslated,
+          "runCSSTransformTest: editorRectTranslated, " + textarea.style.transform) ||
+        !checkRectFuzzy(editorRectTranslated, movedRect(editorRect, 10, 15), {left: 1, top: 1, width: 1, height: 1},
+          "runCSSTransformTest: editorRectTranslated, " + textarea.style.transform)) {
+      return;
+    }
+    let firstCharRectTranslated = synthesizeQueryTextRect(0, 1);
+    if (!checkQueryContentResult(firstCharRectTranslated,
+          "runCSSTransformTest: firstCharRectTranslated, " + textarea.style.transform) ||
+        !checkRectFuzzy(firstCharRectTranslated, movedRect(firstCharRect, 10, 15), {left: 1, top: 1, width: 1, height: 1},
+          "runCSSTransformTest: firstCharRectTranslated, " + textarea.style.transform)) {
+      return;
+    }
+    let lastCharRectTranslated = synthesizeQueryTextRect(textarea.value.length - 1, textarea.value.length);
+    if (!checkQueryContentResult(lastCharRectTranslated,
+          "runCSSTransformTest: lastCharRectTranslated, " + textarea.style.transform) ||
+        !checkRectFuzzy(lastCharRectTranslated, movedRect(lastCharRect, 10, 15), {left: 1, top: 1, width: 1, height: 1},
+          "runCSSTransformTest: lastCharRectTranslated, " + textarea.style.transform)) {
+      return;
+    }
+    let caretRectTranslated = synthesizeQueryCaretRect(textarea.selectionStart);
+    if (!checkQueryContentResult(caretRectTranslated,
+          "runCSSTransformTest: caretRectTranslated, " + textarea.style.transform) ||
+        !checkRectFuzzy(caretRectTranslated, movedRect(caretRect, 10, 15), {left: 1, top: 1, width: 1, height: 1},
+          "runCSSTransformTest: caretRectTranslated, " + textarea.style.transform)) {
+      return;
+    }
+    let caretRectBeforeFirstCharTranslated = synthesizeQueryCaretRect(0);
+    if (!checkQueryContentResult(caretRectBeforeFirstCharTranslated,
+          "runCSSTransformTest: caretRectBeforeFirstCharTranslated, " + textarea.style.transform) ||
+        !checkRectFuzzy(caretRectBeforeFirstCharTranslated, movedRect(caretRectBeforeFirstChar, 10, 15), {left: 1, top: 1, width: 1, height: 1},
+          "runCSSTransformTest: caretRectBeforeFirstCharTranslated, " + textarea.style.transform)) {
+      return;
+    }
+    let firstCharRectTranslatedAsArray = synthesizeQueryTextRectArray(0, 1);
+    if (!checkQueryContentResult(firstCharRectTranslatedAsArray, "runCSSTransformTest: firstCharRectTranslatedAsArray, " + textarea.style.transform) ||
+        !checkRectArray(firstCharRectTranslatedAsArray, [firstCharRectTranslated], "runCSSTransformTest: firstCharRectTranslatedAsArray, " + textarea.style.transform)) {
+      return;
+    }
+    let lastCharRectTranslatedAsArray = synthesizeQueryTextRectArray(textarea.value.length - 1, textarea.value.length);
+    if (!checkQueryContentResult(lastCharRectTranslatedAsArray, "runCSSTransformTest: lastCharRectTranslatedAsArray, " + textarea.style.transform) ||
+        !checkRectArray(lastCharRectTranslatedAsArray, [lastCharRectTranslated], "runCSSTransformTest: lastCharRectTranslatedAsArray, " + textarea.style.transform)) {
+      return;
+    }
+
+    // XXX It's too difficult to check the result with scale and rotate...
+    //     For now, let's check if query text rect and query text rect array returns same rect.
+    textarea.style.transform = "scale(1.5)";
+    firstCharRectTranslated = synthesizeQueryTextRect(0, 1);
+    if (!checkQueryContentResult(firstCharRectTranslated,
+          "runCSSTransformTest: firstCharRectTranslated, " + textarea.style.transform)) {
+      return;
+    }
+    lastCharRectTranslated = synthesizeQueryTextRect(textarea.value.length - 1, textarea.value.length);
+    if (!checkQueryContentResult(lastCharRectTranslated,
+          "runCSSTransformTest: lastCharRectTranslated, " + textarea.style.transform)) {
+      return;
+    }
+    firstCharRectTranslatedAsArray = synthesizeQueryTextRectArray(0, 1);
+    if (!checkQueryContentResult(firstCharRectTranslatedAsArray, "runCSSTransformTest: firstCharRectTranslatedAsArray, " + textarea.style.transform) ||
+        !checkRectArray(firstCharRectTranslatedAsArray, [firstCharRectTranslated], "runCSSTransformTest: firstCharRectTranslatedAsArray, " + textarea.style.transform)) {
+      return;
+    }
+    lastCharRectTranslatedAsArray = synthesizeQueryTextRectArray(textarea.value.length - 1, textarea.value.length);
+    if (!checkQueryContentResult(lastCharRectTranslatedAsArray, "runCSSTransformTest: lastCharRectTranslatedAsArray, " + textarea.style.transform) ||
+        !checkRectArray(lastCharRectTranslatedAsArray, [lastCharRectTranslated], "runCSSTransformTest: lastCharRectTranslatedAsArray, " + textarea.style.transform)) {
+      return;
+    }
+
+    textarea.style.transform = "rotate(30deg)";
+    firstCharRectTranslated = synthesizeQueryTextRect(0, 1);
+    if (!checkQueryContentResult(firstCharRectTranslated,
+          "runCSSTransformTest: firstCharRectTranslated, " + textarea.style.transform)) {
+      return;
+    }
+    lastCharRectTranslated = synthesizeQueryTextRect(textarea.value.length - 1, textarea.value.length);
+    if (!checkQueryContentResult(lastCharRectTranslated,
+          "runCSSTransformTest: lastCharRectTranslated, " + textarea.style.transform)) {
+      return;
+    }
+    firstCharRectTranslatedAsArray = synthesizeQueryTextRectArray(0, 1);
+    if (!checkQueryContentResult(firstCharRectTranslatedAsArray, "runCSSTransformTest: firstCharRectTranslatedAsArray, " + textarea.style.transform) ||
+        !checkRectArray(firstCharRectTranslatedAsArray, [firstCharRectTranslated], "runCSSTransformTest: firstCharRectTranslatedAsArray, " + textarea.style.transform)) {
+      return;
+    }
+    lastCharRectTranslatedAsArray = synthesizeQueryTextRectArray(textarea.value.length - 1, textarea.value.length);
+    checkQueryContentResult(lastCharRectTranslatedAsArray, "runCSSTransformTest: lastCharRectTranslatedAsArray, " + textarea.style.transform);
+    checkRectArray(lastCharRectTranslatedAsArray, [lastCharRectTranslated], "runCSSTransformTest: lastCharRectTranslatedAsArray, " + textarea.style.transform);
+  } finally {
+    textarea.style.transform = "";
+  }
+}
+
+function runBug722639Test()
+{
+  textarea.focus();
+  textarea.value = "\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n";
+  textarea.value += textarea.value;
+  textarea.value += textarea.value; // 80 characters
+
+  let firstLine = synthesizeQueryTextRect(0, 1);
+  if (!checkQueryContentResult(firstLine,
+        "runBug722639Test: firstLine")) {
+    return;
+  }
+  ok(true, "runBug722639Test: 1st line, top=" + firstLine.top + ", left=" + firstLine.left);
+  let firstLineAsArray = synthesizeQueryTextRectArray(0, 1);
+  if (!checkQueryContentResult(firstLineAsArray, "runBug722639Test: 1st line as array") ||
+      !checkRectArray(firstLineAsArray, [firstLine], "runBug722639Test: 1st line as array should match with text rect result")) {
+    return;
+  }
+  if (kLFLen > 1) {
+    let firstLineLF = synthesizeQueryTextRect(1, 1);
+    if (!checkQueryContentResult(firstLineLF,
+          "runBug722639Test: firstLineLF")) {
+      return;
+    }
+    is(firstLineLF.top, firstLine.top, "runBug722639Test: 1st line's \\n rect should be same as 1st line's \\r rect");
+    is(firstLineLF.left, firstLine.left, "runBug722639Test: 1st line's \\n rect should be same as 1st line's \\r rect");
+    isfuzzy(firstLineLF.height, firstLine.height, 1,
+            "runBug722639Test: 1st line's \\n rect should be same as 1st line's \\r rect");
+    is(firstLineLF.width, firstLine.width, "runBug722639Test: 1st line's \\n rect should be same as 1st line's \\r rect");
+    let firstLineLFAsArray = synthesizeQueryTextRectArray(1, 1);
+    if (!checkQueryContentResult(firstLineLFAsArray, "runBug722639Test: 1st line's \\n rect as array") ||
+        !checkRectArray(firstLineLFAsArray, [firstLineLF], "runBug722639Test: 1st line's rect as array should match with text rect result")) {
+      return;
+    }
+  }
+  let secondLine = synthesizeQueryTextRect(kLFLen, 1);
+  if (!checkQueryContentResult(secondLine,
+        "runBug722639Test: secondLine")) {
+    return;
+  }
+  ok(true, "runBug722639Test: 2nd line, top=" + secondLine.top + ", left=" + secondLine.left);
+  let secondLineAsArray = synthesizeQueryTextRectArray(kLFLen, 1);
+  if (!checkQueryContentResult(secondLineAsArray, "runBug722639Test: 2nd line as array") ||
+      !checkRectArray(secondLineAsArray, [secondLine], "runBug722639Test: 2nd line as array should match with text rect result")) {
+    return;
+  }
+  if (kLFLen > 1) {
+    let secondLineLF = synthesizeQueryTextRect(kLFLen + 1, 1);
+    if (!checkQueryContentResult(secondLineLF,
+          "runBug722639Test: secondLineLF")) {
+      return;
+    }
+    is(secondLineLF.top, secondLine.top, "runBug722639Test: 2nd line's \\n rect should be same as 2nd line's \\r rect");
+    is(secondLineLF.left, secondLine.left, "runBug722639Test: 2nd line's \\n rect should be same as 2nd line's \\r rect");
+    isfuzzy(secondLineLF.height, secondLine.height, 1,
+            "runBug722639Test: 2nd line's \\n rect should be same as 2nd line's \\r rect");
+    is(secondLineLF.width, secondLine.width, "runBug722639Test: 2nd line's \\n rect should be same as 2nd line's \\r rect");
+    let secondLineLFAsArray = synthesizeQueryTextRectArray(kLFLen + 1, 1);
+    if (!checkQueryContentResult(secondLineLFAsArray, "runBug722639Test: 2nd line's \\n rect as array") ||
+        !checkRectArray(secondLineLFAsArray, [secondLineLF], "runBug722639Test: 2nd line's rect as array should match with text rect result")) {
+      return;
+    }
+  }
+  let lineHeight = secondLine.top -  firstLine.top;
+  ok(lineHeight > 0,
+     "runBug722639Test: lineHeight must be positive");
+  is(secondLine.left, firstLine.left,
+     "runBug722639Test: the left value must be always same value");
+  isfuzzy(secondLine.height, firstLine.height, 1,
+     "runBug722639Test: the height must be always same value");
+  let previousTop = secondLine.top;
+  for (let i = 3; i <= textarea.value.length + 1; i++) {
+    let currentLine = synthesizeQueryTextRect(kLFLen * (i - 1), 1);
+    if (!checkQueryContentResult(currentLine,
+           "runBug722639Test: " + i + "th currentLine")) {
+      return;
+    }
+    ok(true, "runBug722639Test: " + i + "th line, top=" + currentLine.top + ", left=" + currentLine.left);
+    let currentLineAsArray = synthesizeQueryTextRectArray(kLFLen * (i - 1), 1);
+    if (!checkQueryContentResult(currentLineAsArray, "runBug722639Test: " + i + "th line as array") ||
+        !checkRectArray(currentLineAsArray, [currentLine], "runBug722639Test: " + i + "th line as array should match with text rect result")) {
+      return;
+    }
+    // NOTE: the top position may be 1px larger or smaller than other lines
+    //       due to sub pixel positioning.
+    if (Math.abs(currentLine.top - (previousTop + lineHeight)) <= 1) {
+      ok(true, "runBug722639Test: " + i + "th line's top is expected");
+    } else {
+      is(currentLine.top, previousTop + lineHeight,
+         "runBug722639Test: " + i + "th line's top is unexpected");
+    }
+    is(currentLine.left, firstLine.left,
+       "runBug722639Test: " + i + "th line's left is unexpected");
+    isfuzzy(currentLine.height, firstLine.height, 1,
+            `runBug722639Test: ${i}th line's height is unexpected`);
+    if (kLFLen > 1) {
+      let currentLineLF = synthesizeQueryTextRect(kLFLen * (i - 1) + 1, 1);
+      if (!checkQueryContentResult(currentLineLF,
+            "runBug722639Test: " + i + "th currentLineLF")) {
+        return;
+      }
+      is(currentLineLF.top, currentLine.top, "runBug722639Test: " + i + "th line's \\n rect should be same as same line's \\r rect");
+      is(currentLineLF.left, currentLine.left, "runBug722639Test: " + i + "th line's \\n rect should be same as same line's \\r rect");
+      isfuzzy(currentLineLF.height, currentLine.height, 1,
+              `runBug722639Test: ${i}th line's \\n rect should be same as same line's \\r rect`);
+      is(currentLineLF.width, currentLine.width, "runBug722639Test: " + i + "th line's \\n rect should be same as same line's \\r rect");
+      let currentLineLFAsArray = synthesizeQueryTextRectArray(kLFLen * (i - 1) + 1, 1);
+      if (!checkQueryContentResult(currentLineLFAsArray, "runBug722639Test: " + i + "th line's \\n rect as array") ||
+          !checkRectArray(currentLineLFAsArray, [currentLineLF], "runBug722639Test: " + i + "th line's rect as array should match with text rect result")) {
+        return;
+      }
+    }
+    previousTop = currentLine.top;
+  }
+}
+
+function runCompositionWithSelectionChange() {
+  function doTest(aEditor, aDescription) {
+    aEditor.focus();
+    const isHTMLEditor =
+      aEditor.nodeName.toLowerCase() != "input" && aEditor.nodeName.toLowerCase() != "textarea";
+    const win = isHTMLEditor ? windowOfContenteditable : window;
+    function getValue() {
+      return isHTMLEditor ? aEditor.innerHTML : aEditor.value;
+    }
+    function setSelection(aStart, aLength) {
+      if (isHTMLEditor) {
+        win.getSelection().setBaseAndExtent(aEditor.firstChild, aStart, aEditor.firstChild, aStart + aLength);
+      } else {
+        aEditor.setSelectionRange(aStart, aStart + aLength);
+      }
+    }
+
+    if (isHTMLEditor) {
+      aEditor.innerHTML = "abcxyz";
+    } else {
+      aEditor.value = "abcxyz";
+    }
+    setSelection("abc".length, 0);
+
+    synthesizeCompositionChange({
+      composition: {
+        string: "1",
+        clauses: [{ length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE}],
+        caret: { start: 1, length: 0 },
+      }
+    });
+
+    is(getValue(), "abc1xyz",
+      `${aDescription}: First composing character should be inserted middle of the text`);
+
+    aEditor.addEventListener("compositionupdate", () => {
+      setSelection("abc".length, "1".length);
+    }, {once: true});
+
+    synthesizeCompositionChange({
+      composition: {
+        string: "12",
+        clauses: [{ length: 2, attr: COMPOSITION_ATTR_RAW_CLAUSE}],
+        caret: { start: 2, length: 0 },
+      }
+    });
+
+    is(getValue(), "abc12xyz",
+      `${aDescription}: Only composition string should be updated even if selection range is updated by "compositionupdate" event listener`);
+
+    aEditor.addEventListener("compositionupdate", () => {
+      setSelection("abc1".length, "2d".length);
+    }, {once: true});
+
+    synthesizeCompositionChange({
+      composition: {
+        string: "123",
+        clauses: [{ length: 3, attr: COMPOSITION_ATTR_RAW_CLAUSE}],
+        caret: { start: 3, length: 0 },
+      }
+    });
+
+    is(getValue(), "abc123xyz",
+      `${aDescription}: Only composition string should be updated even if selection range wider than composition string is updated by "compositionupdate" event listener`);
+
+    aEditor.addEventListener("compositionupdate", () => {
+      setSelection("ab".length, "c123d".length);
+    }, {once: true});
+
+    synthesizeCompositionChange({
+      composition: {
+        string: "456",
+        clauses: [{ length: 3, attr: COMPOSITION_ATTR_RAW_CLAUSE}],
+        caret: { start: 3, length: 0 },
+      }
+    });
+
+    is(getValue(), "abc456xyz",
+      `${aDescription}: Only composition string should be updated even if selection range which covers all over the composition string is updated by "compositionupdate" event listener`);
+
+    aEditor.addEventListener("beforeinput", () => {
+      setSelection("abc456d".length, 0);
+    }, {once: true});
+
+    synthesizeComposition({ type: "compositioncommitasis" });
+
+    is(getValue(), "abc456xyz",
+      `${aDescription}: Only composition string should be updated when committing composition but selection is updated by "beforeinput" event listener`);
+    if (isHTMLEditor) {
+      is(win.getSelection().focusNode, aEditor.firstChild,
+        `${aDescription}: The focus node after composition should be the text node`);
+      is(win.getSelection().focusOffset, "abc456".length,
+        `${aDescription}: The focus offset after composition should be end of the composition string`);
+      is(win.getSelection().anchorNode, aEditor.firstChild,
+        `${aDescription}: The anchor node after composition should be the text node`);
+      is(win.getSelection().anchorOffset, "abc456".length,
+        `${aDescription}: The anchor offset after composition should be end of the composition string`);
+    } else {
+      is(aEditor.selectionStart, "abc456".length,
+        `${aDescription}: The selectionStart after composition should be end of the composition string`);
+      is(aEditor.selectionEnd, "abc456".length,
+        `${aDescription}: The selectionEnd after composition should be end of the composition string`);
+    }
+  }
+  doTest(textarea, "runCompositionWithSelectionChange(textarea)");
+  doTest(input, "runCompositionWithSelectionChange(input)");
+  doTest(contenteditable, "runCompositionWithSelectionChange(contenteditable)");
+}
+
+function runForceCommitTest()
+{
+  let events;
+  function eventHandler(aEvent)
+  {
+    events.push(aEvent);
+  }
+  window.addEventListener("compositionstart", eventHandler, true);
+  window.addEventListener("compositionupdate", eventHandler, true);
+  window.addEventListener("compositionend", eventHandler, true);
+  window.addEventListener("beforeinput", eventHandler, true);
+  window.addEventListener("input", eventHandler, true);
+  window.addEventListener("text", eventHandler, true);
+
+  // Make the composition in textarea commit by click in the textarea
+  textarea.focus();
+  textarea.value = "";
+
+  events = [];
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  is(events.length, 5,
+     "runForceCommitTest: wrong event count #1");
+  is(events[0].type, "compositionstart",
+     "runForceCommitTest: the 1st event must be compositionstart #1");
+  is(events[1].type, "compositionupdate",
+     "runForceCommitTest: the 2nd event must be compositionupdate #1");
+  is(events[2].type, "text",
+     "runForceCommitTest: the 3rd event must be text #1");
+  is(events[3].type, "beforeinput",
+     "runForceCommitTest: the 4th event must be beforeinput #1");
+  checkInputEvent(events[3], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #1");
+  is(events[4].type, "input",
+     "runForceCommitTest: the 5th event must be input #1");
+  checkInputEvent(events[4], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #1");
+
+  events = [];
+  synthesizeMouseAtCenter(textarea, {});
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #2");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #2");
+  is(events[0].target, textarea,
+     `runForceCommitTest: The "${events[0].type}" event was fired on wrong event target #2`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #2");
+  is(events[1].target, textarea,
+     `runForceCommitTest: The "${events[1].type}" event was fired on wrong event target #2`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #2");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #2");
+  is(events[2].target, textarea,
+     `runForceCommitTest: The "${events[2].type}" event was fired on wrong event target #2`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #2");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #2");
+  is(events[3].target, textarea,
+     `runForceCommitTest: The "${events[3].type}" event was fired on wrong event target #2`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #2");
+  ok(!getEditor(textarea).isComposing,
+     "runForceCommitTest: the textarea still has composition #2");
+  is(textarea.value, "\u306E",
+     "runForceCommitTest: the textarea doesn't have the committed text #2");
+
+  // Make the composition in textarea commit by click in another editor (input)
+  textarea.focus();
+  textarea.value = "";
+  input.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  synthesizeMouseAtCenter(input, {});
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #3");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #3");
+  is(events[0].target, textarea,
+     `runForceCommitTest: The "${events[0].type}" event was fired on wrong event target #3`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #3");
+  is(events[1].target, textarea,
+     `runForceCommitTest: The "${events[1].type}" event was fired on wrong event target #3`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #3");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #3");
+  is(events[2].target, textarea,
+     `runForceCommitTest: The "${events[2].type}" event was fired on wrong event target #3`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #3");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #3");
+  is(events[3].target, textarea,
+     `runForceCommitTest: The "${events[3].type}" event was fired on wrong event target #3`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #3");
+  ok(!getEditor(textarea).isComposing,
+     "runForceCommitTest: the textarea still has composition #3");
+  ok(!getEditor(input).isComposing,
+     "runForceCommitTest: the input has composition #3");
+  is(textarea.value, "\u306E",
+     "runForceCommitTest: the textarea doesn't have the committed text #3");
+  is(input.value, "",
+     "runForceCommitTest: the input has the committed text? #3");
+
+  // Make the composition in textarea commit by blur()
+  textarea.focus();
+  textarea.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  textarea.blur();
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #4");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #4");
+  is(events[0].target, textarea,
+     `runForceCommitTest: The "${events[0].type}" event was fired on wrong event target #4`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #4");
+  is(events[1].target, textarea,
+     `runForceCommitTest: The "${events[1].type}" event was fired on wrong event target #4`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #4");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #4");
+  is(events[2].target, textarea,
+     `runForceCommitTest: The "${events[2].type}" event was fired on wrong event target #4`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #4");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #4");
+  is(events[3].target, textarea,
+     `runForceCommitTest: The "${events[3].type}" event was fired on wrong event target #4`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #4");
+  ok(!getEditor(textarea).isComposing,
+     "runForceCommitTest: the textarea still has composition #4");
+  is(textarea.value, "\u306E",
+     "runForceCommitTest: the textarea doesn't have the committed text #4");
+
+  // Make the composition in textarea commit by input.focus()
+  textarea.focus();
+  textarea.value = "";
+  input.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  input.focus();
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #5");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #5");
+  is(events[0].target, textarea,
+     `runForceCommitTest: The "${events[0].type}" event was fired on wrong event target #5`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #5");
+  is(events[1].target, textarea,
+     `runForceCommitTest: The "${events[1].type}" event was fired on wrong event target #5`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #5");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #5");
+  is(events[2].target, textarea,
+     `runForceCommitTest: The "${events[2].type}" event was fired on wrong event target #5`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #5");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #5");
+  is(events[3].target, textarea,
+     `runForceCommitTest: The "${events[3].type}" event was fired on wrong event target #5`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #5");
+  ok(!getEditor(textarea).isComposing,
+     "runForceCommitTest: the textarea still has composition #5");
+  ok(!getEditor(input).isComposing,
+     "runForceCommitTest: the input has composition #5");
+  is(textarea.value, "\u306E",
+     "runForceCommitTest: the textarea doesn't have the committed text #5");
+  is(input.value, "",
+     "runForceCommitTest: the input has the committed text? #5");
+
+  // Make the composition in textarea commit by click in another document's editor
+  textarea.focus();
+  textarea.value = "";
+  textareaInFrame.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  synthesizeMouseAtCenter(textareaInFrame, {}, iframe.contentWindow);
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #6");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #6");
+  is(events[0].target, textarea,
+     `runForceCommitTest: The "${events[0].type}" event was fired on wrong event target #6`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #6");
+  is(events[1].target, textarea,
+     `runForceCommitTest: The "${events[1].type}" event was fired on wrong event target #6`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #6");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #6");
+  is(events[2].target, textarea,
+     `runForceCommitTest: The "${events[2].type}" event was fired on wrong event target #6`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #6");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #6");
+  is(events[3].target, textarea,
+     `runForceCommitTest: The "${events[3].type}" event was fired on wrong event target #6`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #6");
+  ok(!getEditor(textarea).isComposing,
+     "runForceCommitTest: the textarea still has composition #6");
+  ok(!getEditor(textareaInFrame).isComposing,
+     "runForceCommitTest: the textarea in frame has composition #6");
+  is(textarea.value, "\u306E",
+     "runForceCommitTest: the textarea doesn't have the committed text #6");
+  is(textareaInFrame.value, "",
+     "runForceCommitTest: the textarea in frame has the committed text? #6");
+
+  // Make the composition in textarea commit by another document's editor's focus()
+  textarea.focus();
+  textarea.value = "";
+  textareaInFrame.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  textareaInFrame.focus();
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #7");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #7");
+  is(events[0].target, textarea,
+     `runForceCommitTest: The "${events[0].type}" event was fired on wrong event target #7`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #7");
+  is(events[1].target, textarea,
+     `runForceCommitTest: The "${events[1].type}" event was fired on wrong event target #7`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #7");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #7");
+  is(events[2].target, textarea,
+     `runForceCommitTest: The "${events[2].type}" event was fired on wrong event target #7`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #7");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #7");
+  is(events[3].target, textarea,
+     `runForceCommitTest: The "${events[3].type}" event was fired on wrong event target #7`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #7");
+  ok(!getEditor(textarea).isComposing,
+     "runForceCommitTest: the textarea still has composition #7");
+  ok(!getEditor(textareaInFrame).isComposing,
+     "runForceCommitTest: the textarea in frame has composition #7");
+  is(textarea.value, "\u306E",
+     "runForceCommitTest: the textarea doesn't have the committed text #7");
+  is(textareaInFrame.value, "",
+     "runForceCommitTest: the textarea in frame has the committed text? #7");
+
+  // Make the composition in a textarea commit by click in another editable document
+  textarea.focus();
+  textarea.value = "";
+  iframe2.contentDocument.body.innerHTML = "Text in the Body";
+  let iframe2BodyInnerHTML = iframe2.contentDocument.body.innerHTML;
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  synthesizeMouseAtCenter(iframe2.contentDocument.body, {}, iframe2.contentWindow);
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #8");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #8");
+  is(events[0].target, textarea,
+     `runForceCommitTest: The ${events[0].type} event was fired on wrong event target #8`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #8");
+  is(events[1].target, textarea,
+     `runForceCommitTest: The ${events[1].type} event was fired on wrong event target #8`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #8");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #8");
+  is(events[2].target, textarea,
+     `runForceCommitTest: The ${events[2].type} event was fired on wrong event target #8`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #8");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #8");
+  is(events[3].target, textarea,
+     `runForceCommitTest: The ${events[3].type} event was fired on wrong event target #8`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #8");
+  ok(!getEditor(textarea).isComposing,
+     "runForceCommitTest: the textarea still has composition #8");
+  ok(!getHTMLEditorIMESupport(iframe2.contentWindow).isComposing,
+     "runForceCommitTest: the editable document has composition #8");
+  is(textarea.value, "\u306E",
+     "runForceCommitTest: the textarea doesn't have the committed text #8");
+  is(iframe2.contentDocument.body.innerHTML, iframe2BodyInnerHTML,
+     "runForceCommitTest: the editable document has the committed text? #8");
+
+  // Make the composition in an editable document commit by click in it
+  iframe2.contentWindow.focus();
+  iframe2.contentDocument.body.innerHTML = "Text in the Body";
+  iframe2BodyInnerHTML = iframe2.contentDocument.body.innerHTML;
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    }, iframe2.contentWindow);
+
+  events = [];
+  synthesizeMouseAtCenter(iframe2.contentDocument.body, {}, iframe2.contentWindow);
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #9");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #9");
+  is(events[0].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The "${events[0].type}" event was fired on wrong event target #9`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #9");
+  is(events[1].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The "${events[1].type}" event was fired on wrong event target #9`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E",
+                  [{startContainer: iframe2.contentDocument.body.firstChild,
+                    startOffset: iframe2.contentDocument.body.firstChild.wholeText.indexOf("\u306E"),
+                    endContainer: iframe2.contentDocument.body.firstChild,
+                    endOffset: iframe2.contentDocument.body.firstChild.wholeText.indexOf("\u306E") + 1}],
+                  "runForceCommitTest #9");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #9");
+  is(events[2].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The "${events[2].type}" event was fired on wrong event target #9`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #9");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #9");
+  is(events[3].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The "${events[3].type}" event was fired on wrong event target #9`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #9");
+  ok(!getHTMLEditorIMESupport(iframe2.contentWindow).isComposing,
+     "runForceCommitTest: the editable document still has composition #9");
+  ok(iframe2.contentDocument.body.innerHTML != iframe2BodyInnerHTML &&
+     iframe2.contentDocument.body.innerHTML.includes("\u306E"),
+     "runForceCommitTest: the editable document doesn't have the committed text #9");
+
+  // Make the composition in an editable document commit by click in another document's editor
+  textarea.value = "";
+  iframe2.contentWindow.focus();
+  iframe2.contentDocument.body.innerHTML = "Text in the Body";
+  iframe2BodyInnerHTML = iframe2.contentDocument.body.innerHTML;
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    }, iframe2.contentWindow);
+
+  events = [];
+  synthesizeMouseAtCenter(textarea, {});
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #10");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #10");
+  is(events[0].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The ${events[0].type} event was fired on wrong event target #10`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #10");
+  is(events[1].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The ${events[1].type} event was fired on wrong event target #10`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E",
+                  [{startContainer: iframe2.contentDocument.body.firstChild,
+                    startOffset: iframe2.contentDocument.body.firstChild.wholeText.indexOf("\u306E"),
+                    endContainer: iframe2.contentDocument.body.firstChild,
+                    endOffset: iframe2.contentDocument.body.firstChild.wholeText.indexOf("\u306E") + 1}],
+                  "runForceCommitTest #10");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #10");
+  is(events[2].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The ${events[2].type} event was fired on wrong event target #10`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #10");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #10");
+  is(events[3].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The ${events[3].type} event was fired on wrong event target #10`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #10");
+  ok(!getHTMLEditorIMESupport(iframe2.contentWindow).isComposing,
+     "runForceCommitTest: the editable document still has composition #10");
+  ok(!getEditor(textarea).isComposing,
+     "runForceCommitTest: the textarea has composition #10");
+  ok(iframe2.contentDocument.body.innerHTML != iframe2BodyInnerHTML &&
+     iframe2.contentDocument.body.innerHTML.includes("\u306E"),
+     "runForceCommitTest: the editable document doesn't have the committed text #10");
+  is(textarea.value, "",
+     "runForceCommitTest: the textarea has the committed text? #10");
+
+  // Make the composition in an editable document commit by click in the another editable document
+  iframe2.contentWindow.focus();
+  iframe2.contentDocument.body.innerHTML = "Text in the Body";
+  iframe2BodyInnerHTML = iframe2.contentDocument.body.innerHTML;
+  iframe3.contentDocument.body.innerHTML = "Text in the Body";
+  let iframe3BodyInnerHTML = iframe2.contentDocument.body.innerHTML;
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    }, iframe2.contentWindow);
+
+  events = [];
+  synthesizeMouseAtCenter(iframe3.contentDocument.body, {}, iframe3.contentWindow);
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #11");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #11");
+  is(events[0].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The "${events[0].type}" event was fired on wrong event target #11`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #11");
+  is(events[1].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The "${events[1].type}" event was fired on wrong event target #11`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E",
+                  [{startContainer: iframe2.contentDocument.body.firstChild,
+                    startOffset: iframe2.contentDocument.body.firstChild.wholeText.indexOf("\u306E"),
+                    endContainer: iframe2.contentDocument.body.firstChild,
+                    endOffset: iframe2.contentDocument.body.firstChild.wholeText.indexOf("\u306E") + 1}],
+                  "runForceCommitTest #11");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #11");
+  is(events[2].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The "${events[2].type}" event was fired on wrong event target #11`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #11");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #11");
+  is(events[3].target, iframe2.contentDocument.body,
+     `runForceCommitTest: The "${events[3].type}" event was fired on wrong event target #11`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #11");
+  ok(!getHTMLEditorIMESupport(iframe2.contentWindow).isComposing,
+     "runForceCommitTest: the editable document still has composition #11");
+  ok(!getHTMLEditorIMESupport(iframe3.contentWindow).isComposing,
+     "runForceCommitTest: the other editable document has composition #11");
+  ok(iframe2.contentDocument.body.innerHTML != iframe2BodyInnerHTML &&
+     iframe2.contentDocument.body.innerHTML.includes("\u306E"),
+     "runForceCommitTest: the editable document doesn't have the committed text #11");
+  is(iframe3.contentDocument.body.innerHTML, iframe3BodyInnerHTML,
+     "runForceCommitTest: the other editable document has the committed text? #11");
+
+  input.focus();
+  input.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  input.value = "set value";
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #12");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #12");
+  is(events[0].target, input,
+     `runForceCommitTest: The "${events[0].type}" event was fired on wrong event target #12`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #12");
+  is(events[1].target, input,
+     `runForceCommitTest: The "${events[1].type}" event was fired on wrong event target #12`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #12");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #12");
+  is(events[2].target, input,
+     `runForceCommitTest: The "${events[2].type}" event was fired on wrong event target #12`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #12");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #12");
+  is(events[3].target, input,
+     `runForceCommitTest: The "${events[3].type}" event was fired on wrong event target #12`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #12");
+  ok(!getEditor(input).isComposing,
+     "runForceCommitTest: the input still has composition #12");
+  is(input.value, "set value",
+     "runForceCommitTest: the input doesn't have the set text #12");
+
+  textarea.focus();
+  textarea.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  textarea.value = "set value";
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #13");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #13");
+  is(events[0].target, textarea,
+     `runForceCommitTest: The "${events[0].type}" event was fired on wrong event target #13`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #13");
+  is(events[1].target, textarea,
+     `runForceCommitTest: The "${events[1].type}" event was fired on wrong event target #13`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #13");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #13");
+  is(events[2].target, textarea,
+     `runForceCommitTest: The "${events[2].type}" event was fired on wrong event target #13`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #13");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #13");
+  is(events[3].target, textarea,
+     `runForceCommitTest: The "${events[3].type}" event was fired on wrong event target #13`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #13");
+  ok(!getEditor(textarea).isComposing,
+     "runForceCommitTest: the textarea still has composition #13");
+  is(textarea.value, "set value",
+     "runForceCommitTest: the textarea doesn't have the set text #13");
+
+  input.focus();
+  input.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  input.value += " appended value";
+
+  is(events.length, 4,
+     "runForceCommitTest: wrong event count #14");
+  is(events[0].type, "text",
+     "runForceCommitTest: the 1st event must be text #14");
+  is(events[0].target, input,
+     `runForceCommitTest: The "${events[0].type}" event was fired on wrong event target #14`);
+  is(events[1].type, "beforeinput",
+     "runForceCommitTest: the 2nd event must be beforeinput #14");
+  is(events[1].target, input,
+     `runForceCommitTest: The "${events[1].type}" event was fired on wrong event target #14`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #14");
+  is(events[2].type, "compositionend",
+     "runForceCommitTest: the 3rd event must be compositionend #14");
+  is(events[2].target, input,
+     `runForceCommitTest: The "${events[2].type}" event was fired on wrong event target #14`);
+  is(events[2].data, "\u306E",
+     "runForceCommitTest: compositionend has wrong data #14");
+  is(events[3].type, "input",
+     "runForceCommitTest: the 4th event must be input #14");
+  is(events[3].target, input,
+     `runForceCommitTest: The "${events[3].type}" event was fired on wrong event target #14`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runForceCommitTest #14");
+  ok(!getEditor(input).isComposing,
+     "runForceCommitTest: the input still has composition #14");
+  is(input.value, "\u306E appended value",
+     "runForceCommitTest: the input should have both composed text and appended text #14");
+
+  input.focus();
+  input.value = "abcd";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  input.value = "abcd\u306E";
+
+  is(events.length, 0,
+     "runForceCommitTest: setting same value to input with composition shouldn't cause any events #15");
+  is(input.value, "abcd\u306E",
+     "runForceCommitTest: the input has unexpected value #15");
+
+  input.blur(); // commit composition
+
+  textarea.focus();
+  textarea.value = "abcd";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  textarea.value = "abcd\u306E";
+
+  is(events.length, 0,
+     "runForceCommitTest: setting same value to textarea with composition shouldn't cause any events #16");
+  is(textarea.value, "abcd\u306E",
+     "runForceCommitTest: the input has unexpected value #16");
+
+  textarea.blur(); // commit composition
+
+  window.removeEventListener("compositionstart", eventHandler, true);
+  window.removeEventListener("compositionupdate", eventHandler, true);
+  window.removeEventListener("compositionend", eventHandler, true);
+  window.removeEventListener("beforeinput", eventHandler, true);
+  window.removeEventListener("input", eventHandler, true);
+  window.removeEventListener("text", eventHandler, true);
+}
+
+function runNestedSettingValue()
+{
+  let isTesting = false;
+  let events = [];
+  function eventHandler(aEvent)
+  {
+    events.push(aEvent);
+    if (isTesting) {
+      aEvent.target.value += aEvent.type + ", ";
+    }
+  }
+  window.addEventListener("compositionstart", eventHandler, true);
+  window.addEventListener("compositionupdate", eventHandler, true);
+  window.addEventListener("compositionend", eventHandler, true);
+  window.addEventListener("beforeinput", eventHandler, true);
+  window.addEventListener("input", eventHandler, true);
+  window.addEventListener("text", eventHandler, true);
+
+  textarea.focus();
+  textarea.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  isTesting = true;
+  textarea.value = "first setting value, ";
+  isTesting = false;
+
+  is(events.length, 4,
+     "runNestedSettingValue: wrong event count #1");
+  is(events[0].type, "text",
+     "runNestedSettingValue: the 1st event must be text #1");
+  is(events[0].target, textarea,
+     `runNestedSettingValue: The "${events[0].type}" event was fired on wrong event target #1`);
+  is(events[1].type, "beforeinput",
+     "runNestedSettingValue: the 2nd event must be beforeinput #1");
+  is(events[1].target, textarea,
+     `runNestedSettingValue: The "${events[1].type}" event was fired on wrong event target #1`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runNestedSettingValue #1");
+  is(events[2].type, "compositionend",
+     "runNestedSettingValue: the 3rd event must be compositionend #1");
+  is(events[2].target, textarea,
+     `runNestedSettingValue: The "${events[2].type}" event was fired on wrong event target #1`);
+  is(events[2].data, "\u306E",
+     "runNestedSettingValue: compositionend has wrong data #1");
+  is(events[3].type, "input",
+     "runNestedSettingValue: the 4th event must be input #1");
+  is(events[3].target, textarea,
+     `runNestedSettingValue: The "${events[3].type}" event was fired on wrong event target #1`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runNestedSettingValue #1");
+  ok(!getEditor(textarea).isComposing,
+     "runNestedSettingValue: the textarea still has composition #1");
+  is(textarea.value, "first setting value, text, beforeinput, compositionend, input, ",
+     "runNestedSettingValue: the textarea should have all string set to value attribute");
+
+  input.focus();
+  input.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  isTesting = true;
+  input.value = "first setting value, ";
+  isTesting = false;
+
+  is(events.length, 4,
+     "runNestedSettingValue: wrong event count #2");
+  is(events[0].type, "text",
+     "runNestedSettingValue: the 1st event must be text #2");
+  is(events[0].target, input,
+     `runNestedSettingValue: The "${events[0].type}" event was fired on wrong event target #2`);
+  is(events[1].type, "beforeinput",
+     "runNestedSettingValue: the 2nd event must be beforeinput #2");
+  is(events[1].target, input,
+     `runNestedSettingValue: The "${events[1].type}" event was fired on wrong event target #2`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runNestedSettingValue #2");
+  is(events[2].type, "compositionend",
+     "runNestedSettingValue: the 3rd event must be compositionend #2");
+  is(events[2].target, input,
+     `runNestedSettingValue: The "${events[2].type}" event was fired on wrong event target #2`);
+  is(events[2].data, "\u306E",
+     "runNestedSettingValue: compositionend has wrong data #2");
+  is(events[3].type, "input",
+     "runNestedSettingValue: the 4th event must be input #2");
+  is(events[3].target, input,
+     `runNestedSettingValue: The "${events[3].type}" event was fired on wrong event target #2`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runNestedSettingValue #2");
+  ok(!getEditor(input).isComposing,
+     "runNestedSettingValue: the input still has composition #2");
+  is(textarea.value, "first setting value, text, beforeinput, compositionend, input, ",
+     "runNestedSettingValue: the input should have all string set to value attribute #2");
+
+  textarea.focus();
+  textarea.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  isTesting = true;
+  textarea.setRangeText("first setting value, ");
+  isTesting = false;
+
+  is(events.length, 4,
+     "runNestedSettingValue: wrong event count #3");
+  is(events[0].type, "text",
+     "runNestedSettingValue: the 1st event must be text #3");
+  is(events[0].target, textarea,
+     `runNestedSettingValue: The ${events[0].type} event was fired on wrong event target #3`);
+  is(events[1].type, "beforeinput",
+     "runNestedSettingValue: the 2nd event must be beforeinput #3");
+  is(events[1].target, textarea,
+     `runNestedSettingValue: The ${events[1].type} event was fired on wrong event target #3`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runNestedSettingValue #3");
+  is(events[2].type, "compositionend",
+     "runNestedSettingValue: the 3rd event must be compositionend #3");
+  is(events[2].target, textarea,
+     `runNestedSettingValue: The ${events[2].type} event was fired on wrong event target #3`);
+  is(events[2].data, "\u306E",
+     "runNestedSettingValue: compositionend has wrong data #3");
+  is(events[3].type, "input",
+     "runNestedSettingValue: the 4th event must be input #3");
+  is(events[3].target, textarea,
+     `runNestedSettingValue: The ${events[3].type} event was fired on wrong event target #3`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runNestedSettingValue #3");
+  ok(!getEditor(textarea).isComposing,
+     "runNestedSettingValue: the textarea still has composition #3");
+  is(textarea.value, "\u306Efirst setting value, text, beforeinput, compositionend, input, ",
+     "runNestedSettingValue: the textarea should have appended by setRangeText() and all string set to value attribute #3");
+
+  input.focus();
+  input.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  events = [];
+  isTesting = true;
+  input.setRangeText("first setting value, ");
+  isTesting = false;
+
+  is(events.length, 4,
+     "runNestedSettingValue: wrong event count #4");
+  is(events[0].type, "text",
+     "runNestedSettingValue: the 1st event must be text #4");
+  is(events[0].target, input,
+     `runNestedSettingValue: The "${events[0].type}" event was fired on wrong event target #4`);
+  is(events[1].type, "beforeinput",
+     "runNestedSettingValue: the 2nd event must be beforeinput #4");
+  is(events[1].target, input,
+     `runNestedSettingValue: The "${events[1].type}" event was fired on wrong event target #4`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runNestedSettingValue #4");
+  is(events[2].type, "compositionend",
+     "runNestedSettingValue: the 3rd event must be compositionend #4");
+  is(events[2].target, input,
+     `runNestedSettingValue: The "${events[2].type}" event was fired on wrong event target #4`);
+  is(events[2].data, "\u306E",
+     "runNestedSettingValue: compositionend has wrong data #4");
+  is(events[3].type, "input",
+     "runNestedSettingValue: the 4th event must be input #4");
+  is(events[3].target, input,
+     `runNestedSettingValue: The "${events[3].type}" event was fired on wrong event target #4`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runNestedSettingValue #4");
+  ok(!getEditor(input).isComposing,
+     "runNestedSettingValue: the input still has composition #4");
+  is(textarea.value, "\u306Efirst setting value, text, beforeinput, compositionend, input, ",
+     "runNestedSettingValue: the input should have all string appended by setRangeText() and set to value attribute #4");
+
+  window.removeEventListener("compositionstart", eventHandler, true);
+  window.removeEventListener("compositionupdate", eventHandler, true);
+  window.removeEventListener("compositionend", eventHandler, true);
+  window.removeEventListener("beforeinput", eventHandler, true);
+  window.removeEventListener("input", eventHandler, true);
+  window.removeEventListener("text", eventHandler, true);
+
+}
+
+async function runAsyncForceCommitTest()
+{
+  let events;
+  function eventHandler(aEvent)
+  {
+    events.push(aEvent);
+  };
+
+  // If IME commits composition for a request, TextComposition commits
+  // composition automatically because most web apps must expect that active
+  // composition should be committed synchronously.  Therefore, in this case,
+  // a click during composition should cause committing composition
+  // synchronously and delayed commit shouldn't cause composition events.
+  let commitRequested = false;
+  let onFinishTest = null;
+  function callback(aTIP, aNotification)
+  {
+    ok(true, aNotification.type);
+    if (aNotification.type != "request-to-commit") {
+      return true;
+    }
+    commitRequested = true;
+    if (onFinishTest) {
+      let resolve = onFinishTest;
+      onFinishTest = null;
+
+      SimpleTest.executeSoon(() => {
+        events = [];
+        aTIP.commitComposition();
+
+        is(events.length, 0,
+           "runAsyncForceCommitTest: composition events shouldn't been fired by asynchronous call of nsITextInputProcessor.commitComposition()");
+
+        SimpleTest.executeSoon(resolve);
+      });
+    }
+    return true;
+  };
+
+  function promiseCleanUp() {
+    return new Promise(resolve => { onFinishTest = resolve; });
+  }
+
+  window.addEventListener("compositionstart", eventHandler, true);
+  window.addEventListener("compositionupdate", eventHandler, true);
+  window.addEventListener("compositionend", eventHandler, true);
+  window.addEventListener("beforeinput", eventHandler, true);
+  window.addEventListener("input", eventHandler, true);
+  window.addEventListener("text", eventHandler, true);
+
+  // Make the composition in textarea commit by click in the textarea
+  textarea.focus();
+  textarea.value = "";
+
+  events = [];
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    }, window, callback);
+
+  is(events.length, 5,
+     "runAsyncForceCommitTest: wrong event count #1");
+  is(events[0].type, "compositionstart",
+     "runAsyncForceCommitTest: the 1st event must be compositionstart #1");
+  is(events[1].type, "compositionupdate",
+     "runAsyncForceCommitTest: the 2nd event must be compositionupdate #1");
+  is(events[2].type, "text",
+     "runAsyncForceCommitTest: the 3rd event must be text #1");
+  is(events[3].type, "beforeinput",
+     "runAsyncForceCommitTest: the 4th event must be beforeinput #1");
+  checkInputEvent(events[3], true, "insertCompositionText", "\u306E", [],
+                  "runAsyncForceCommitTest #1");
+  is(events[4].type, "input",
+     "runAsyncForceCommitTest: the 5th event must be input #1");
+  checkInputEvent(events[4], true, "insertCompositionText", "\u306E", [],
+                  "runAsyncForceCommitTest #1");
+
+  events = [];
+  let waitCleanState = promiseCleanUp();
+
+  synthesizeMouseAtCenter(textarea, {});
+
+  ok(commitRequested,
+     "runAsyncForceCommitTest: \"request-to-commit\" should've been notified");
+  is(events.length, 4,
+     "runAsyncForceCommitTest: wrong event count #2");
+  is(events[0].type, "text",
+     "runAsyncForceCommitTest: the 1st event must be text #2");
+  is(events[0].target, textarea,
+     `runAsyncForceCommitTest: The "${events[0].type}" event was fired on wrong event target #2`);
+  is(events[1].type, "beforeinput",
+     "runAsyncForceCommitTest: the 2nd event must be beforeinput #2");
+  is(events[1].target, textarea,
+     `runAsyncForceCommitTest: The "${events[1].type}" event was fired on wrong event target #2`);
+  checkInputEvent(events[1], true, "insertCompositionText", "\u306E", [],
+                  "runAsyncForceCommitTest #2");
+  is(events[2].type, "compositionend",
+     "runAsyncForceCommitTest: the 3rd event must be compositionend #2");
+  is(events[2].target, textarea,
+     `runAsyncForceCommitTest: The "${events[2].type}" event was fired on wrong event target #2`);
+  is(events[2].data, "\u306E",
+     "runAsyncForceCommitTest: compositionend has wrong data #2");
+  is(events[3].type, "input",
+     "runAsyncForceCommitTest: the 4th event must be input #2");
+  is(events[3].target, textarea,
+     `runAsyncForceCommitTest: The "${events[3].type}" event was fired on wrong event target #2`);
+  checkInputEvent(events[3], false, "insertCompositionText", "\u306E", [],
+                  "runAsyncForceCommitTest #2");
+  ok(!getEditor(textarea).isComposing,
+     "runAsyncForceCommitTest: the textarea still has composition #2");
+  is(textarea.value, "\u306E",
+     "runAsyncForceCommitTest: the textarea doesn't have the committed text #2");
+
+  await waitCleanState;
+
+  window.removeEventListener("compositionstart", eventHandler, true);
+  window.removeEventListener("compositionupdate", eventHandler, true);
+  window.removeEventListener("compositionend", eventHandler, true);
+  window.removeEventListener("beforeinput", eventHandler, true);
+  window.removeEventListener("input", eventHandler, true);
+  window.removeEventListener("text", eventHandler, true);
+}
+
+function runBug811755Test()
+{
+  iframe2.contentDocument.body.innerHTML = "<div>content<br/></div>";
+  iframe2.contentWindow.focus();
+  // Query everything
+  let textContent = synthesizeQueryTextContent(0, 10);
+  if (!checkQueryContentResult(textContent, "runBug811755Test: synthesizeQueryTextContent #1")) {
+    return;
+  }
+  // Query everything but specify exact end offset, which should be immediately after the <br> node
+  // If PreContentIterator is used, the next node after <br> is the node after </div>.
+  // If ContentIterator is used, the next node is the <div> node itself. In this case, the end
+  // node ends up being before the start node, and an empty string is returned.
+  let queryContent = synthesizeQueryTextContent(0, textContent.text.length);
+  if (!checkQueryContentResult(queryContent, "runBug811755Test: synthesizeQueryTextContent #2")) {
+    return;
+  }
+  is(queryContent.text, textContent.text, "runBug811755Test: two queried texts don't match");
+}
+
+function runIsComposingTest()
+{
+  let expectedIsComposing = false;
+  let description = "";
+
+  function eventHandler(aEvent)
+  {
+    if (aEvent.type == "keydown" || aEvent.type == "keyup") {
+      is(aEvent.isComposing, expectedIsComposing,
+         "runIsComposingTest: " + description + " (type=" + aEvent.type + ", key=" + aEvent.key + ")");
+    } else if (aEvent.type == "keypress") {
+      // keypress event shouldn't be fired during composition so that isComposing should be always false.
+      is(aEvent.isComposing, false,
+         "runIsComposingTest: " + description + " (type=" + aEvent.type + ")");
+    } else {
+      checkInputEvent(aEvent, expectedIsComposing, "insertCompositionText", "\u3042", [],
+                      `runIsComposingTest: ${description}`);
+    }
+  }
+
+  function onComposition(aEvent)
+  {
+    if (aEvent.type == "compositionstart") {
+      expectedIsComposing = true;
+    } else if (aEvent.type == "compositionend") {
+      expectedIsComposing = false;
+    }
+  }
+
+  textarea.addEventListener("keydown", eventHandler, true);
+  textarea.addEventListener("keypress", eventHandler, true);
+  textarea.addEventListener("keyup", eventHandler, true);
+  textarea.addEventListener("beforeinput", eventHandler, true);
+  textarea.addEventListener("input", eventHandler, true);
+  textarea.addEventListener("compositionstart", onComposition, true);
+  textarea.addEventListener("compositionend", onComposition, true);
+
+  textarea.focus();
+  textarea.value = "";
+
+  // XXX These cases shouldn't occur in actual native key events because we
+  //     don't dispatch key events while composition (bug 354358).
+  description = "events before dispatching compositionstart";
+  synthesizeKey("KEY_ArrowLeft");
+
+  description = "events after dispatching compositionchange";
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 },
+      "key": { key: "a", code: "KeyA", keyCode: KeyboardEvent.DOM_VK_A },
+    });
+
+  // Although, firing keypress event during composition is a bug.
+  synthesizeKey("KEY_Insert");
+
+  description = "events for committing composition string";
+
+  synthesizeComposition({ type: "compositioncommitasis",
+                          key: { key: "KEY_Enter", code: "Enter", type: "keydown" } });
+
+  // input event will be fired by synthesizing compositionend event.
+  // Then, its isComposing should be false.
+  description = "events after dispatching compositioncommitasis";
+  synthesizeKey("KEY_Enter", {type: "keyup"});
+
+  textarea.removeEventListener("keydown", eventHandler, true);
+  textarea.removeEventListener("keypress", eventHandler, true);
+  textarea.removeEventListener("keyup", eventHandler, true);
+  textarea.removeEventListener("beforeinput", eventHandler, true);
+  textarea.removeEventListener("input", eventHandler, true);
+  textarea.removeEventListener("compositionstart", onComposition, true);
+  textarea.removeEventListener("compositionend", onComposition, true);
+
+  textarea.value = "";
+}
+
+function runRedundantChangeTest()
+{
+  textarea.focus();
+
+  let result = [];
+  function clearResult()
+  {
+    result = [];
+  }
+
+  function handler(aEvent)
+  {
+    result.push(aEvent);
+  }
+
+  textarea.addEventListener("compositionupdate", handler, true);
+  textarea.addEventListener("compositionend", handler, true);
+  textarea.addEventListener("beforeinput", handler, true);
+  textarea.addEventListener("input", handler, true);
+  textarea.addEventListener("text", handler, true);
+
+  textarea.value = "";
+
+  // synthesize change event
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  is(result.length, 4,
+     "runRedundantChangeTest: 4 events should be fired after synthesizing composition change #1");
+  is(result[0].type, "compositionupdate",
+     "runRedundantChangeTest: compositionupdate should be fired after synthesizing composition change #1");
+  is(result[1].type, "text",
+     "runRedundantChangeTest: text should be fired after synthesizing composition change because it's dispatched when there is composing string #1");
+  is(result[2].type, "beforeinput",
+     "runRedundantChangeTest: beforeinput should be fired after synthesizing composition change #1");
+  checkInputEvent(result[2], true, "insertCompositionText", "\u3042", [],
+                  "runRedundantChangeTest: after synthesizing composition change #1");
+  is(result[3].type, "input",
+     "runRedundantChangeTest: input should be fired after synthesizing composition change #1");
+  checkInputEvent(result[3], true, "insertCompositionText", "\u3042", [],
+                  "runRedundantChangeTest: after synthesizing composition change #1");
+  is(textarea.value, "\u3042", "runRedundantChangeTest: textarea has uncommitted string #1");
+
+  // synthesize another change event
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042\u3044",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 }
+    });
+
+  is(result.length, 4,
+     "runRedundantChangeTest: 4 events should be fired after synthesizing composition change #2");
+  is(result[0].type, "compositionupdate",
+     "runRedundantChangeTest: compositionupdate should be fired after synthesizing composition change #2");
+  is(result[1].type, "text",
+     "runRedundantChangeTest: text should be fired after synthesizing composition change because it's dispatched when there is composing string #2");
+  is(result[2].type, "beforeinput",
+     "runRedundantChangeTest: beforeinput should be fired after synthesizing composition change #2");
+  checkInputEvent(result[2], true, "insertCompositionText", "\u3042\u3044", [],
+                  "runRedundantChangeTest: after synthesizing composition change #2");
+  is(result[3].type, "input",
+     "runRedundantChangeTest: input should be fired after synthesizing composition change #2");
+  checkInputEvent(result[3], true, "insertCompositionText", "\u3042\u3044", [],
+                  "runRedundantChangeTest: after synthesizing composition change #2");
+  is(textarea.value, "\u3042\u3044", "runRedundantChangeTest: textarea has uncommitted string #2");
+
+  // synthesize same change event again
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3042\u3044",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 }
+    });
+
+  is(result.length, 0, "runRedundantChangeTest: no events should be fired after synthesizing composition change again");
+  is(textarea.value, "\u3042\u3044", "runRedundantChangeTest: textarea has uncommitted string #3");
+
+  // synthesize commit-as-is
+  clearResult();
+  synthesizeComposition({ type: "compositioncommitasis" });
+  is(result.length, 4,
+     "runRedundantChangeTest: 4 events should be fired after synthesizing composition commit-as-is");
+  is(result[0].type, "text",
+     "runRedundantChangeTest: text should be fired after synthesizing composition commit-as-is for removing the ranges");
+  is(result[1].type, "beforeinput",
+     "runRedundantChangeTest: beforeinput should be fired after synthesizing composition commit-as-is for removing the ranges");
+  checkInputEvent(result[1], true, "insertCompositionText", "\u3042\u3044", [],
+                  "runRedundantChangeTest: at synthesizing commit-as-is");
+  is(result[2].type, "compositionend",
+     "runRedundantChangeTest: compositionend should be fired after synthesizing composition commit-as-is");
+  is(result[3].type, "input",
+     "runRedundantChangeTest: input should be fired before compositionend at synthesizing commit-as-is");
+  checkInputEvent(result[3], false, "insertCompositionText", "\u3042\u3044", [],
+                  "runRedundantChangeTest: at synthesizing commit-as-is");
+  is(textarea.value, "\u3042\u3044", "runRedundantChangeTest: textarea has the commit string");
+
+  textarea.removeEventListener("compositionupdate", handler, true);
+  textarea.removeEventListener("compositionend", handler, true);
+  textarea.removeEventListener("beforeinput", handler, true);
+  textarea.removeEventListener("input", handler, true);
+  textarea.removeEventListener("text", handler, true);
+}
+
+function runNotRedundantChangeTest()
+{
+  textarea.focus();
+
+  let result = [];
+  function clearResult()
+  {
+    result = [];
+  }
+
+  function handler(aEvent)
+  {
+    result.push(aEvent);
+  }
+
+  textarea.addEventListener("compositionupdate", handler, true);
+  textarea.addEventListener("compositionend", handler, true);
+  textarea.addEventListener("beforeinput", handler, true);
+  textarea.addEventListener("input", handler, true);
+  textarea.addEventListener("text", handler, true);
+
+  textarea.value = "abcde";
+
+  // synthesize change event with non-null ranges
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "ABCDE",
+        "clauses":
+        [
+          { "length": 5, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 5, "length": 0 }
+    });
+
+  is(result.length, 4,
+     "runNotRedundantChangeTest: 4 events should be fired after synthesizing composition change with non-null ranges");
+  is(result[0].type, "compositionupdate",
+     "runNotRedundantChangeTest: compositionupdate should be fired after synthesizing composition change with non-null ranges");
+  is(result[1].type, "text",
+     "runNotRedundantChangeTest: text should be fired after synthesizing composition change because it's dispatched when there is composing string with non-null ranges");
+  is(result[2].type, "beforeinput",
+     "runNotRedundantChangeTest: beforeinput should be fired after synthesizing composition change with non-null ranges");
+  checkInputEvent(result[2], true, "insertCompositionText", "ABCDE", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with non-null ranges");
+  is(result[3].type, "input",
+     "runNotRedundantChangeTest: input should be fired after synthesizing composition change with non-null ranges");
+  checkInputEvent(result[3], true, "insertCompositionText", "ABCDE", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with non-null ranges");
+  is(textarea.value, "abcdeABCDE", "runNotRedundantChangeTest: textarea has uncommitted string #1");
+
+  // synthesize change event with null ranges
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "ABCDE",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+    });
+  is(result.length, 3,
+     "runNotRedundantChangeTest: 3 events should be fired after synthesizing composition change with null ranges after non-null ranges");
+  is(result[0].type, "text",
+     "runNotRedundantChangeTest: text should be fired after synthesizing composition change because it's dispatched when there is composing string with null ranges after non-null ranges");
+  is(result[1].type, "beforeinput",
+     "runNotRedundantChangeTest: beforeinput should be fired after synthesizing composition change because it's dispatched when there is composing string with null ranges after non-null ranges");
+  checkInputEvent(result[1], true, "insertCompositionText", "ABCDE", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with null ranges after non-null ranges");
+  is(result[2].type, "input",
+     "runNotRedundantChangeTest: input should be fired after synthesizing composition change with null ranges after non-null ranges");
+  checkInputEvent(result[2], true, "insertCompositionText", "ABCDE", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with null ranges after non-null ranges");
+  is(textarea.value, "abcdeABCDE", "runNotRedundantChangeTest: textarea has uncommitted string #2");
+
+  // synthesize change event with non-null ranges
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "ABCDE",
+        "clauses":
+        [
+          { "length": 5, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 5, "length": 0 }
+    });
+
+  is(result.length, 3,
+     "runNotRedundantChangeTest: 3 events should be fired after synthesizing composition change with null ranges after non-null ranges");
+  is(result[0].type, "text",
+     "runNotRedundantChangeTest: text should be fired after synthesizing composition change because it's dispatched when there is composing string with non-null ranges after null ranges");
+  is(result[1].type, "beforeinput",
+     "runNotRedundantChangeTest: beforeinput should be fired after synthesizing composition change because it's dispatched when there is composing string with non-null ranges after null ranges");
+  checkInputEvent(result[1], true, "insertCompositionText", "ABCDE", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with non-null ranges after null ranges");
+  is(result[2].type, "input",
+     "runNotRedundantChangeTest: input should be fired after synthesizing composition change with non-null ranges after null ranges");
+  checkInputEvent(result[2], true, "insertCompositionText", "ABCDE", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with non-null ranges after null ranges");
+  is(textarea.value, "abcdeABCDE", "runNotRedundantChangeTest: textarea has uncommitted string #3");
+
+  // synthesize change event with empty data and null ranges
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "",
+        "clauses":
+        [
+          { "length": 0, "attr": 0 }
+        ]
+      },
+    });
+  is(result.length, 4,
+     "runNotRedundantChangeTest: 4 events should be fired after synthesizing composition change with empty data and null ranges after non-null ranges");
+  is(result[0].type, "compositionupdate",
+     "runNotRedundantChangeTest: compositionupdate should be fired after synthesizing composition change with empty data and null ranges after non-null ranges");
+  is(result[1].type, "text",
+     "runNotRedundantChangeTest: text should be fired after synthesizing composition change because it's dispatched when there is composing string with empty data and null ranges after non-null ranges");
+  is(result[2].type, "beforeinput",
+     "runNotRedundantChangeTest: beforeinput should be fired after synthesizing composition change with empty data and null ranges after non-null ranges");
+  checkInputEvent(result[2], true, "insertCompositionText", "", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with empty data and null ranges after non-null ranges");
+  is(result[3].type, "input",
+     "runNotRedundantChangeTest: input should be fired after synthesizing composition change with empty data and null ranges after non-null ranges");
+  checkInputEvent(result[3], true, "insertCompositionText", "", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with empty data and null ranges after non-null ranges");
+  is(textarea.value, "abcde", "runNotRedundantChangeTest: textarea doesn't have uncommitted string #1");
+
+  // synthesize change event with non-null ranges
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "ABCDE",
+        "clauses":
+        [
+          { "length": 5, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 5, "length": 0 }
+    });
+
+  is(result.length, 4,
+     "runNotRedundantChangeTest: 4 events should be fired after synthesizing composition change with non-null ranges after empty data and null ranges");
+  is(result[0].type, "compositionupdate",
+     "runNotRedundantChangeTest: compositionupdate should be fired after synthesizing composition change with non-null ranges after empty data and null ranges");
+  is(result[1].type, "text",
+     "runNotRedundantChangeTest: text should be fired after synthesizing composition change because it's dispatched when there is composing string with non-null ranges after empty data and null ranges");
+  is(result[2].type, "beforeinput",
+     "runNotRedundantChangeTest: beforeinput should be fired after synthesizing composition change with non-null ranges after empty data and null ranges");
+  checkInputEvent(result[2], true, "insertCompositionText", "ABCDE", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with non-null ranges after empty data and null ranges");
+  is(result[3].type, "input",
+     "runNotRedundantChangeTest: input should be fired after synthesizing composition change with non-null ranges after empty data and null ranges");
+  checkInputEvent(result[3], true, "insertCompositionText", "ABCDE", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with non-null ranges after empty data and null ranges");
+  is(textarea.value, "abcdeABCDE", "runNotRedundantChangeTest: textarea has uncommitted string #4");
+
+  clearResult();
+  synthesizeComposition({ type: "compositioncommit", data: "" });
+
+  is(result.length, 5,
+     "runNotRedundantChangeTest: 5 events should be fired after synthesizing composition commit with empty data after non-empty data");
+  is(result[0].type, "compositionupdate",
+     "runNotRedundantChangeTest: compositionupdate should be fired after synthesizing composition commit with empty data after non-empty data");
+  is(result[1].type, "text",
+     "runNotRedundantChangeTest: text should be fired after synthesizing composition change because it's dispatched when there is composing string with empty data after non-empty data");
+  is(result[2].type, "beforeinput",
+     "runNotRedundantChangeTest: beforeinput should be fired after synthesizing composition commit with empty data after non-empty data");
+  checkInputEvent(result[2], true, "insertCompositionText", "", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with empty data after non-empty data");
+  is(result[3].type, "compositionend",
+     "runNotRedundantChangeTest: compositionend should be fired after synthesizing composition commit with empty data after non-empty data");
+  is(result[4].type, "input",
+     "runNotRedundantChangeTest: input should be fired after compositionend after synthesizing composition change with empty data after non-empty data");
+  checkInputEvent(result[4], false, "insertCompositionText", "", [],
+                  "runNotRedundantChangeTest: after synthesizing composition change with empty data after non-empty data");
+  is(textarea.value, "abcde", "runNotRedundantChangeTest: textarea doesn't have uncommitted string #2");
+
+  textarea.removeEventListener("compositionupdate", handler, true);
+  textarea.removeEventListener("compositionend", handler, true);
+  textarea.removeEventListener("beforeinput", handler, true);
+  textarea.removeEventListener("input", handler, true);
+  textarea.removeEventListener("text", handler, true);
+}
+
+function runNativeLineBreakerTest()
+{
+  textarea.focus();
+
+  let result = {};
+  function clearResult()
+  {
+    result = { compositionupdate: null, compositionend: null };
+  }
+
+  function handler(aEvent)
+  {
+    result[aEvent.type] = aEvent.data;
+  }
+
+  Services.prefs.setBoolPref("dom.compositionevent.allow_control_characters", false);
+
+  textarea.addEventListener("compositionupdate", handler, true);
+  textarea.addEventListener("compositionend", handler, true);
+
+  // '\n' in composition string shouldn't be changed.
+  clearResult();
+  textarea.value = "";
+  let clauses = [ "abc\n", "def\n\ng", "hi\n", "\njkl" ];
+  let caret = clauses[0] + clauses[1] + clauses[2];
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": clauses.join(''),
+        "clauses":
+        [
+          { "length": clauses[0].length,
+            "attr": COMPOSITION_ATTR_RAW_CLAUSE },
+          { "length": clauses[1].length,
+            "attr": COMPOSITION_ATTR_SELECTED_RAW_CLAUSE },
+          { "length": clauses[2].length,
+            "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE },
+          { "length": clauses[3].length,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+        ]
+      },
+      "caret": { "start": caret.length, "length": 0 }
+    });
+
+  checkSelection(caret.replace(/\n/g, "\n").length + (kLFLen - 1) * 4, "", "runNativeLineBreakerTest", "#1");
+  checkIMESelection("RawClause", true, 0, clauses[0].replace(/\n/g, kLF), "runNativeLineBreakerTest: \\n shouldn't be replaced with any character #1");
+  checkIMESelection("SelectedRawClause", true, clauses[0].replace(/\n/g, kLF).length, clauses[1].replace(/\n/g, kLF), "runNativeLineBreakerTest: \\n shouldn't be replaced with any character #1");
+  checkIMESelection("ConvertedClause", true, (clauses[0] + clauses[1]).replace(/\n/g, kLF).length, clauses[2].replace(/\n/g, kLF), "runNativeLineBreakerTest: \\n shouldn't be replaced with any character #1");
+  checkIMESelection("SelectedClause", true, (clauses[0] + clauses[1] + clauses[2]).replace(/\n/g, kLF).length, clauses[3].replace(/\n/g, kLF), "runNativeLineBreakerTest: \\n shouldn't be replaced with any character #1");
+  is(result.compositionupdate, clauses.join('').replace(/\n/g, "\n"), "runNativeLineBreakerTest: \\n in compositionupdate.data shouldn't be removed nor replaced with other characters #1");
+  is(textarea.value, clauses.join('').replace(/\n/g, "\n"), "runNativeLineBreakerTest: \\n in textarea.value shouldn't be removed nor replaced with other characters #1");
+
+  synthesizeComposition({ type: "compositioncommit", data: clauses.join('') });
+  checkSelection(clauses.join('').replace(/\n/g, "\n").length + (kLFLen - 1) * 5, "", "runNativeLineBreakerTest", "#2");
+  is(result.compositionend, clauses.join('').replace(/\n/g, "\n"), "runNativeLineBreakerTest: \\n in compositionend.data shouldn't be removed nor replaced with other characters #2");
+  is(textarea.value, clauses.join('').replace(/\n/g, "\n"), "runNativeLineBreakerTest: \\n in textarea.value shouldn't be removed nor replaced with other characters #2");
+
+  // \r\n in composition string should be replaced with \n.
+  clearResult();
+  textarea.value = "";
+  clauses = [ "abc\r\n", "def\r\n\r\ng", "hi\r\n", "\r\njkl" ];
+  caret = clauses[0] + clauses[1] + clauses[2];
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": clauses.join(''),
+        "clauses":
+        [
+          { "length": clauses[0].length,
+            "attr": COMPOSITION_ATTR_RAW_CLAUSE },
+          { "length": clauses[1].length,
+            "attr": COMPOSITION_ATTR_SELECTED_RAW_CLAUSE },
+          { "length": clauses[2].length,
+            "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE },
+          { "length": clauses[3].length,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+        ]
+      },
+      "caret": { "start": caret.length, "length": 0 }
+    });
+
+  checkSelection(caret.replace(/\r\n/g, "\n").length + (kLFLen - 1) * 4, "", "runNativeLineBreakerTest", "#3");
+  checkIMESelection("RawClause", true, 0, clauses[0].replace(/\r\n/g, kLF), "runNativeLineBreakerTest: \\r\\n should be replaced with \\n #3");
+  checkIMESelection("SelectedRawClause", true, clauses[0].replace(/\r\n/g, kLF).length, clauses[1].replace(/\r\n/g, kLF), "runNativeLineBreakerTest: \\r\\n should be replaced with \\n #3");
+  checkIMESelection("ConvertedClause", true, (clauses[0] + clauses[1]).replace(/\r\n/g, kLF).length, clauses[2].replace(/\r\n/g, kLF), "runNativeLineBreakerTest: \\r\\n should be replaced with \\n #3");
+  checkIMESelection("SelectedClause", true, (clauses[0] + clauses[1] + clauses[2]).replace(/\r\n/g, kLF).length, clauses[3].replace(/\r\n/g, kLF), "runNativeLineBreakerTest: \\r\\n should be replaced with \\n #3");
+  is(result.compositionupdate, clauses.join('').replace(/\r\n/g, "\n"), "runNativeLineBreakerTest: \\r\\n in compositionudpate.data should be replaced with \\n #3");
+  is(textarea.value, clauses.join('').replace(/\r\n/g, "\n"), "runNativeLineBreakerTest: \\r\\n in textarea.value should be replaced with \\n #3");
+
+  synthesizeComposition({ type: "compositioncommit", data: clauses.join('') });
+  checkSelection(clauses.join('').replace(/\r\n/g, "\n").length + (kLFLen - 1) * 5, "", "runNativeLineBreakerTest", "#4");
+  is(result.compositionend, clauses.join('').replace(/\r\n/g, "\n"), "runNativeLineBreakerTest: \\r\\n in compositionend.data should be replaced with \\n #4");
+  is(textarea.value, clauses.join('').replace(/\r\n/g, "\n"), "runNativeLineBreakerTest: \\r\\n in textarea.value should be replaced with \\n #4");
+
+  // \r (not followed by \n) in composition string should be replaced with \n.
+  clearResult();
+  textarea.value = "";
+  clauses = [ "abc\r", "def\r\rg", "hi\r", "\rjkl" ];
+  caret = clauses[0] + clauses[1] + clauses[2];
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": clauses.join(''),
+        "clauses":
+        [
+          { "length": clauses[0].length,
+            "attr": COMPOSITION_ATTR_RAW_CLAUSE },
+          { "length": clauses[1].length,
+            "attr": COMPOSITION_ATTR_SELECTED_RAW_CLAUSE },
+          { "length": clauses[2].length,
+            "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE },
+          { "length": clauses[3].length,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+        ]
+      },
+      "caret": { "start": caret.length, "length": 0 }
+    });
+
+  checkSelection(caret.replace(/\r/g, "\n").length + (kLFLen - 1) * 4, "", "runNativeLineBreakerTest", "#5");
+  checkIMESelection("RawClause", true, 0, clauses[0].replace(/\r/g, kLF), "runNativeLineBreakerTest: \\r should be replaced with \\n #5");
+  checkIMESelection("SelectedRawClause", true, clauses[0].replace(/\r/g, kLF).length, clauses[1].replace(/\r/g, kLF), "runNativeLineBreakerTest: \\r should be replaced with \\n #5");
+  checkIMESelection("ConvertedClause", true, (clauses[0] + clauses[1]).replace(/\r/g, kLF).length, clauses[2].replace(/\r/g, kLF), "runNativeLineBreakerTest: \\r should be replaced with \\n #5");
+  checkIMESelection("SelectedClause", true, (clauses[0] + clauses[1] + clauses[2]).replace(/\r/g, kLF).length, clauses[3].replace(/\r/g, kLF), "runNativeLineBreakerTest: \\r should be replaced with \\n #5");
+  is(result.compositionupdate, clauses.join('').replace(/\r/g, "\n"), "runNativeLineBreakerTest: \\r in compositionupdate.data should be replaced with \\n #5");
+  is(textarea.value, clauses.join('').replace(/\r/g, "\n"), "runNativeLineBreakerTest: \\r in textarea.value should be replaced with \\n #5");
+
+  synthesizeComposition({ type: "compositioncommit", data: clauses.join('') });
+  checkSelection(clauses.join('').replace(/\r/g, "\n").length + (kLFLen - 1) * 5, "", "runNativeLineBreakerTest", "#6");
+  is(result.compositionend, clauses.join('').replace(/\r/g, "\n"), "runNativeLineBreakerTest: \\r in compositionend.data should be replaced with \\n #6");
+  is(textarea.value, clauses.join('').replace(/\r/g, "\n"), "runNativeLineBreakerTest: \\r in textarea.value should be replaced with \\n #6");
+
+  textarea.removeEventListener("compositionupdate", handler, true);
+  textarea.removeEventListener("compositionend", handler, true);
+
+  Services.prefs.clearUserPref("dom.compositionevent.allow_control_characters");
+}
+
+function runControlCharTest()
+{
+  textarea.focus();
+
+  let result = {};
+  function clearResult()
+  {
+    result = { compositionupdate: null, compositionend: null };
+  }
+
+  function handler(aEvent)
+  {
+    result[aEvent.type] = aEvent.data;
+  }
+
+  textarea.addEventListener("compositionupdate", handler, true);
+  textarea.addEventListener("compositionend", handler, true);
+
+  textarea.value = "";
+
+  let controlChars = String.fromCharCode.apply(null, Object.keys(Array.from({length:0x20}))) + "\x7F";
+  let allowedChars = "\t\n\n";
+
+  let data = "AB" + controlChars + "CD" + controlChars + "EF";
+  let removedData = "AB" + allowedChars + "CD" + allowedChars + "EF";
+
+  let DIndex = data.indexOf("D");
+  let removedDIndex = removedData.indexOf("D");
+
+  // input string contains control characters
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": data,
+        "clauses":
+        [
+          { "length": DIndex,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+          { "length": data.length - DIndex,
+            "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": DIndex, "length": 0 }
+    });
+
+  checkSelection(removedDIndex + (kLFLen - 1) * 2, "", "runControlCharTest", "#1")
+
+  is(result.compositionupdate, removedData, "runControlCharTest: control characters in event.data should be removed in compositionupdate event #1");
+  is(textarea.value, removedData, "runControlCharTest: control characters should not appear in textarea #1");
+
+  synthesizeComposition({ type: "compositioncommit", data });
+
+  is(result.compositionend, removedData, "runControlCharTest: control characters in event.data should be removed in compositionend event #2");
+  is(textarea.value, removedData, "runControlCharTest: control characters should not appear in textarea #2");
+
+  textarea.value = "";
+
+  clearResult();
+
+  Services.prefs.setBoolPref("dom.compositionevent.allow_control_characters", true);
+
+  // input string contains control characters, allowing control characters
+  clearResult();
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": data,
+        "clauses":
+        [
+          { "length": DIndex,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+          { "length": data.length - DIndex,
+            "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": DIndex, "length": 0 }
+    });
+
+  checkSelection(DIndex + (kLFLen - 1) * 2, "", "runControlCharTest", "#3")
+
+  is(result.compositionupdate, data.replace(/\r/g, "\n"), "runControlCharTest: control characters in event.data should not be removed in compositionupdate event #3");
+  is(textarea.value, data.replace(/\r/g, "\n"), "runControlCharTest: control characters should appear in textarea #3");
+
+  synthesizeComposition({ type: "compositioncommit", data });
+
+  is(result.compositionend, data.replace(/\r/g, "\n"), "runControlCharTest: control characters in event.data should not be removed in compositionend event #4");
+  is(textarea.value, data.replace(/\r/g, "\n"), "runControlCharTest: control characters should appear in textarea #4");
+
+  Services.prefs.clearUserPref("dom.compositionevent.allow_control_characters");
+
+  textarea.removeEventListener("compositionupdate", handler, true);
+  textarea.removeEventListener("compositionend", handler, true);
+}
+
+async function runRemoveContentTest()
+{
+  let events = [];
+  function eventHandler(aEvent)
+  {
+    events.push(aEvent);
+  }
+  textarea.addEventListener("compositionstart", eventHandler, true);
+  textarea.addEventListener("compositionupdate", eventHandler, true);
+  textarea.addEventListener("compositionend", eventHandler, true);
+  textarea.addEventListener("beforeinput", eventHandler, true);
+  textarea.addEventListener("input", eventHandler, true);
+  textarea.addEventListener("text", eventHandler, true);
+
+  textarea.focus();
+  textarea.value = "";
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u306E",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  let nextSibling = textarea.nextSibling;
+  let parent = textarea.parentElement;
+
+  events = [];
+  parent.removeChild(textarea);
+
+  await waitForEventLoops(50);
+
+  // XXX Currently, "input" event and "beforeinput" event are not fired on removed content.
+  is(events.length, 3,
+     "runRemoveContentTest: wrong event count #1");
+  is(events[0].type, "compositionupdate",
+     "runRemoveContentTest: the 1st event must be compositionupdate #1");
+  is(events[0].target, textarea,
+     `runRemoveContentTest: The "${events[0].type}" event was fired on wrong event target #1`);
+  is(events[0].data, "",
+     "runRemoveContentTest: compositionupdate has wrong data #1");
+  is(events[1].type, "text",
+     "runRemoveContentTest: the 2nd event must be text #1");
+  is(events[1].target, textarea,
+     `runRemoveContentTest: The "${events[1].type}" event was fired on wrong event target #1`);
+  todo_is(events[2].type, "beforeinput",
+     "runRemoveContentTest: the 3rd event must be beforeinput #1");
+  // is(events[2].target, textarea,
+  //    `runRemoveContentTest: The "${events[2].type}" event was fired on wrong event target #1`);
+  // checkInputEvent(events[2], true, "insertCompositionText", "", [],
+  //                 "runRemoveContentTest: #1");
+  is(events[2].type, "compositionend",
+     "runRemoveContentTest: the 4th event must be compositionend #1");
+  is(events[2].target, textarea,
+     `runRemoveContentTest: The "${events[2].type}" event was fired on wrong event target #1`);
+  is(events[2].data, "",
+     "runRemoveContentTest: compositionend has wrong data #1");
+  ok(!getEditor(textarea).isComposing,
+     "runRemoveContentTest: the textarea still has composition #1");
+  todo_is(textarea.value, "",
+     "runRemoveContentTest: the textarea has the committed text? #1");
+
+  parent.insertBefore(textarea, nextSibling);
+
+  textarea.focus();
+  textarea.value = "";
+
+  synthesizeComposition({ type: "compositionstart" });
+
+  events = [];
+  parent.removeChild(textarea);
+
+  await waitForEventLoops(50);
+
+  // XXX Currently, "input" event and "beforeinput" event are not fired on removed content.
+  is(events.length, 2,
+     "runRemoveContentTest: wrong event count #2");
+  is(events[0].type, "text",
+     "runRemoveContentTest: the 1st event must be text #2");
+  is(events[0].target, textarea,
+     `runRemoveContentTest: The ${events[0].type} event was fired on wrong event target #2`);
+  todo_is(events[1].type, "beforeinput",
+     "runRemoveContentTest: the 2nd event must be beforeinput #2");
+  // is(events[1].target, textarea,
+  //    `runRemoveContentTest: The ${events[1].type} event was fired on wrong event target #2`);
+  // checkInputEvent(events[1], true, "insertCompositionText", "", [],
+  //                 "runRemoveContentTest: #2");
+  is(events[1].type, "compositionend",
+     "runRemoveContentTest: the 3rd event must be compositionend #2");
+  is(events[1].target, textarea,
+     `runRemoveContentTest: The ${events[1].type} event was fired on wrong event target #2`);
+  is(events[1].data, "",
+     "runRemoveContentTest: compositionupdate has wrong data #2");
+  ok(!getEditor(textarea).isComposing,
+     "runRemoveContentTest: the textarea still has composition #2");
+  is(textarea.value, "",
+     "runRemoveContentTest: the textarea has the committed text? #2");
+
+  parent.insertBefore(textarea, nextSibling);
+
+  textarea.removeEventListener("compositionstart", eventHandler, true);
+  textarea.removeEventListener("compositionupdate", eventHandler, true);
+  textarea.removeEventListener("compositionend", eventHandler, true);
+  textarea.removeEventListener("beforeinput", eventHandler, true);
+  textarea.removeEventListener("input", eventHandler, true);
+  textarea.removeEventListener("text", eventHandler, true);
+
+  await waitForTick();
+}
+
+function runTestOnAnotherContext(aPanelOrFrame, aFocusedEditor, aTestName)
+{
+  aFocusedEditor.value = "";
+
+  // The frames and panel are cross-origin, and we no longer
+  // propagate flushes to parent cross-origin iframes explicitly,
+  // so flush our own layout here so the positions are correct.
+  document.documentElement.getBoundingClientRect();
+
+  let editorRect = synthesizeQueryEditorRect();
+  if (!checkQueryContentResult(editorRect, aTestName + ": editorRect")) {
+    return;
+  }
+
+  let r = aPanelOrFrame.getBoundingClientRect();
+  let parentRect = {
+    left: r.left * window.devicePixelRatio,
+    top: r.top * window.devicePixelRatio,
+    width: (r.right - r.left) * window.devicePixelRatio,
+    height: (r.bottom - r.top) * window.devicePixelRatio,
+  };
+  checkRectContainsRect(editorRect, parentRect, aTestName +
+                        ": the editor rect coordinates are wrong");
+
+  // input characters
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3078\u3093\u3057\u3093",
+        "clauses":
+        [
+          { "length": 4, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 4, "length": 0 }
+    });
+
+  if (!checkContent("\u3078\u3093\u3057\u3093", aTestName, "#1-1") ||
+      !checkSelection(4, "", aTestName, "#1-1")) {
+    return;
+  }
+
+  // convert them #1
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u8FD4\u4FE1",
+        "clauses":
+        [
+          { "length": 2,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 }
+    });
+
+  if (!checkContent("\u8FD4\u4FE1", aTestName, "#1-2") ||
+      !checkSelection(2, "", aTestName, "#1-2")) {
+    return;
+  }
+
+  // convert them #2
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u5909\u8EAB",
+        "clauses":
+        [
+          { "length": 2,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 }
+    });
+
+  if (!checkContent("\u5909\u8EAB", aTestName, "#1-3") ||
+      !checkSelection(2, "", aTestName, "#1-3")) {
+    return;
+  }
+
+  // commit them
+  synthesizeComposition({ type: "compositioncommitasis" });
+  if (!checkContent("\u5909\u8EAB", aTestName, "#1-4") ||
+      !checkSelection(2, "", aTestName, "#1-4")) {
+    return;
+  }
+
+  is(aFocusedEditor.value, "\u5909\u8EAB",
+     aTestName + ": composition isn't in the focused editor");
+  if (aFocusedEditor.value != "\u5909\u8EAB") {
+    return;
+  }
+
+  let textRect = synthesizeQueryTextRect(0, 1);
+  let caretRect = synthesizeQueryCaretRect(2);
+  if (!checkQueryContentResult(textRect,
+                               aTestName + ": synthesizeQueryTextRect") ||
+      !checkQueryContentResult(caretRect,
+                               aTestName + ": synthesizeQueryCaretRect")) {
+    return;
+  }
+  checkRectContainsRect(textRect, editorRect, aTestName + ":testRect");
+  checkRectContainsRect(caretRect, editorRect, aTestName + ":caretRect");
+}
+
+function runFrameTest()
+{
+  textareaInFrame.focus();
+  runTestOnAnotherContext(iframe, textareaInFrame, "runFrameTest");
+  runCharAtPointTest(textareaInFrame, "textarea in the iframe");
+}
+
+async function runPanelTest()
+{
+  panel.hidden = false;
+  let waitOpenPopup = new Promise(resolve => {
+    panel.addEventListener("popupshown", resolve, {once: true});
+  });
+  let waitFocusTextBox = new Promise(resolve => {
+    textbox.addEventListener("focus", resolve, {once: true});
+  });
+  panel.openPopupAtScreen(window.screenX + window.outerWidth, 0, false);
+  await waitOpenPopup;
+  textbox.focus();
+  await waitFocusTextBox;
+  is(panel.state, "open", "The panel should be open (after textbox.focus())");
+  await waitForTick();
+  is(panel.state, "open", "The panel should be open (after waitForTick())");
+  runTestOnAnotherContext(panel, textbox, "runPanelTest");
+  is(panel.state, "open", "The panel should be open (after runTestOnAnotherContext())");
+  runCharAtPointTest(textbox, "textbox in the panel");
+  is(panel.state, "open", "The panel should be open (after runCharAtPointTest())");
+  let waitClosePopup = new Promise(resolve => {
+    panel.addEventListener("popuphidden", resolve, {once: true});
+  });
+  panel.hidePopup();
+  await waitClosePopup;
+  await waitForTick();
+}
+
+// eslint-disable-next-line complexity
+function runMaxLengthTest()
+{
+  input.maxLength = 1;
+  input.value = "";
+  input.focus();
+
+  let kDesc ="runMaxLengthTest";
+
+  // input first character
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  if (!checkContent("\u3089", kDesc, "#1-1") ||
+      !checkSelection(1, "", kDesc, "#1-1")) {
+    return;
+  }
+
+  // input second character
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 }
+    });
+
+  if (!checkContent("\u3089\u30FC", kDesc, "#1-2") ||
+      !checkSelection(2, "", kDesc, "#1-2")) {
+    return;
+  }
+
+  // input third character
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081",
+        "clauses":
+        [
+          { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 3, "length": 0 }
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081", kDesc, "#1-3") ||
+      !checkSelection(3, "", kDesc, "#1-3")) {
+    return;
+  }
+
+  // input fourth character
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093",
+        "clauses":
+        [
+          { "length": 4, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 4, "length": 0 }
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093", kDesc, "#1-4") ||
+      !checkSelection(4, "", kDesc, "#1-4")) {
+    return;
+  }
+
+
+  // backspace
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081",
+        "clauses":
+        [
+          { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 3, "length": 0 }
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081", kDesc, "#1-5") ||
+      !checkSelection(3, "", kDesc, "#1-5")) {
+    return;
+  }
+
+  // re-input
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093",
+        "clauses":
+        [
+          { "length": 4, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 4, "length": 0 }
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093", kDesc, "#1-6") ||
+      !checkSelection(4, "", kDesc, "#1-6")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093\u3055",
+        "clauses":
+        [
+          { "length": 5, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 5, "length": 0 }
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093\u3055", kDesc, "#1-7") ||
+      !checkSelection(5, "", kDesc, "#1-7")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093\u3055\u3044",
+        "clauses":
+        [
+          { "length": 6, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 6, "length": 0 }
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093\u3055\u3044", kDesc, "#1-8") ||
+      !checkSelection(6, "", kDesc, "#1-8")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093\u3055\u3044\u3053",
+        "clauses":
+        [
+          { "length": 7, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 7, "length": 0 }
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093\u3055\u3044\u3053",
+                    kDesc, "#1-8") ||
+      !checkSelection(7, "", kDesc, "#1-8")) {
+    return;
+  }
+
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3089\u30FC\u3081\u3093\u3055\u3044\u3053\u3046",
+        "clauses":
+        [
+          { "length": 8, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 8, "length": 0 }
+    });
+
+  if (!checkContent("\u3089\u30FC\u3081\u3093\u3055\u3044\u3053\u3046",
+                    kDesc, "#1-9") ||
+      !checkSelection(8, "", kDesc, "#1-9")) {
+    return;
+  }
+
+  // convert
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u30E9\u30FC\u30E1\u30F3\u6700\u9AD8",
+        "clauses":
+        [
+          { "length": 4,
+            "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+          { "length": 2,
+            "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE }
+        ]
+      },
+      "caret": { "start": 4, "length": 0 }
+    });
+
+  if (!checkContent("\u30E9\u30FC\u30E1\u30F3\u6700\u9AD8", kDesc, "#1-10") ||
+      !checkSelection(4, "", kDesc, "#1-10")) {
+    return;
+  }
+
+  // commit the composition string
+  synthesizeComposition({ type: "compositioncommitasis" });
+  if (!checkContent("\u30E9", kDesc, "#1-11") ||
+      !checkSelection(1, "", kDesc, "#1-11")) {
+    return;
+  }
+
+  // input characters
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u3057",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  if (!checkContent("\u30E9\u3057", kDesc, "#2-1") ||
+      !checkSelection(1 + 1, "", kDesc, "#2-1")) {
+    return;
+  }
+
+  // commit the composition string
+  synthesizeComposition({ type: "compositioncommit", data: "\u3058" });
+  if (!checkContent("\u30E9", kDesc, "#2-2") ||
+      !checkSelection(1 + 0, "", kDesc, "#2-2")) {
+    return;
+  }
+
+  // Undo
+  synthesizeKey("Z", {accelKey: true});
+
+  // XXX this is unexpected behavior, see bug 258291
+  if (!checkContent("\u30E9", kDesc, "#3-1") ||
+      !checkSelection(1 + 0, "", kDesc, "#3-1")) {
+    return;
+  }
+
+  // Undo
+  synthesizeKey("Z", {accelKey: true});
+  if (!checkContent("", kDesc, "#3-2") ||
+      !checkSelection(0, "", kDesc, "#3-2")) {
+    return;
+  }
+
+  // Redo
+  synthesizeKey("Z", {accelKey: true, shiftKey: true});
+  if (!checkContent("\u30E9", kDesc, "#3-3") ||
+      !checkSelection(1, "", kDesc, "#3-3")) {
+    return;
+  }
+
+  // Redo
+  synthesizeKey("Z", {accelKey: true, shiftKey: true});
+  if (!checkContent("\u30E9", kDesc, "#3-4") ||
+      !checkSelection(1 + 0, "", kDesc, "#3-4")) {
+    return;
+  }
+
+  // The input element whose content length is already maxlength and
+  // the carest is at start of the content.
+  input.value = "X";
+  input.selectionStart = input.selectionEnd = 0;
+
+  // input characters
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u9B54",
+        "clauses":
+        [
+          { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 1, "length": 0 }
+    });
+
+  if (!checkContent("\u9B54X", kDesc, "#4-1") ||
+      !checkSelection(1, "", kDesc, "#4-1")) {
+    return;
+  }
+
+  // commit the composition string
+  synthesizeComposition({ type: "compositioncommitasis" });
+
+  // The input text must be discarded. Then, the caret position shouldn't be
+  // updated from its position at compositionstart.
+  if (!checkContent("X", kDesc, "#4-2") ||
+      !checkSelection(0, "", kDesc, "#4-2")) {
+    return;
+  }
+
+  // input characters
+  synthesizeCompositionChange(
+    { "composition":
+      { "string": "\u9B54\u6CD5",
+        "clauses":
+        [
+          { "length": 2, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+        ]
+      },
+      "caret": { "start": 2, "length": 0 }
+    });
+
+  if (!checkContent("\u9B54\u6CD5X", kDesc, "#5-1") ||
+      !checkSelection(2, "", kDesc, "#5-1")) {
+    return;
+  }
+
+  // commit the composition string
+  synthesizeComposition({ type: "compositioncommitasis" });
+
+  if (checkContent("X", kDesc, "#5-2")) {
+     checkSelection(0, "", kDesc, "#5-2");
+  }
+}
+
+async function runEditorReframeTests()
+{
+  async function runEditorReframeTest(aEditor, aWindow, aEventType)
+  {
+    function getValue()
+    {
+      return aEditor == contenteditable ?
+        aEditor.innerHTML.replace("<br>", "") : aEditor.value;
+    }
+
+    let description = "runEditorReframeTest(" + aEditor.id + ", \"" + aEventType + "\"): ";
+
+    let tests = [
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "a",
+                "clauses":
+                [
+                  { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+                ]
+              },
+              "caret": { "start": 1, "length": 0 }
+            });
+        },
+        check () {
+          is(getValue(aEditor), "a", description + "Typing 'a'");
+        },
+      },
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "ab",
+                "clauses":
+                [
+                  { "length": 2, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+                ]
+              },
+              "caret": { "start": 2, "length": 0 }
+            });
+        },
+        check () {
+          is(getValue(aEditor), "ab", description + "Typing 'b' next to 'a'");
+        },
+      },
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "abc",
+                "clauses":
+                [
+                  { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+                ]
+              },
+              "caret": { "start": 3, "length": 0 }
+            });
+        },
+        check () {
+          is(getValue(aEditor), "abc", description + "Typing 'c' next to 'ab'");
+        },
+      },
+      { test () {
+        synthesizeCompositionChange(
+          { "composition":
+            { "string": "abc",
+              "clauses":
+              [
+                { "length": 2, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+                { "length": 1, "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE }
+              ]
+            },
+            "caret": { "start": 2, "length": 0 }
+          });
+        },
+        check () {
+          is(getValue(aEditor), "abc", description + "Starting to convert 'ab][c'");
+        },
+      },
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "ABc",
+                "clauses":
+                [
+                  { "length": 2, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE },
+                  { "length": 1, "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE }
+                ]
+              },
+              "caret": { "start": 2, "length": 0 }
+            });
+        },
+        check () {
+          is(getValue(aEditor), "ABc", description + "Starting to convert 'AB][c'");
+        },
+      },
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "ABC",
+                "clauses":
+                [
+                  { "length": 2, "attr": COMPOSITION_ATTR_CONVERTED_CLAUSE },
+                  { "length": 1, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+                ]
+              },
+              "caret": { "start": 3, "length": 0 }
+            });
+          },
+        check () {
+          is(getValue(aEditor), "ABC", description + "Starting to convert 'AB][C'");
+        },
+      },
+      { test () {
+          // Commit composition
+          synthesizeComposition({ type: "compositioncommitasis" });
+        },
+        check () {
+          is(getValue(aEditor), "ABC", description + "Committed as 'ABC'");
+        },
+      },
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "d",
+                "clauses":
+                [
+                  { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+                ]
+              },
+              "caret": { "start": 1, "length": 0 }
+            });
+        },
+        check () {
+          is(getValue(aEditor), "ABCd", description + "Typing 'd' next to ABC");
+        },
+      },
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "de",
+                "clauses":
+                [
+                  { "length": 2, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+                ]
+              },
+              "caret": { "start": 2, "length": 0 }
+            });
+        },
+        check () {
+          is(getValue(aEditor), "ABCde", description + "Typing 'e' next to ABCd");
+        },
+      },
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "def",
+                "clauses":
+                [
+                  { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+                ]
+              },
+              "caret": { "start": 3, "length": 0 }
+            });
+        },
+        check () {
+          is(getValue(aEditor), "ABCdef", description + "Typing 'f' next to ABCde");
+        },
+      },
+      { test () {
+          // Commit composition
+          synthesizeComposition({ type: "compositioncommitasis" });
+        },
+        check () {
+          is(getValue(aEditor), "ABCdef", description + "Commit 'def' without convert");
+        },
+      },
+      { test () {
+          // Select "Cd"
+          synthesizeKey("KEY_ArrowLeft");
+          synthesizeKey("KEY_ArrowLeft");
+          synthesizeKey("KEY_Shift", {type: "keydown", shiftKey: true});
+          synthesizeKey("KEY_ArrowLeft", {shiftKey: true});
+          synthesizeKey("KEY_ArrowLeft", {shiftKey: true});
+          synthesizeKey("KEY_Shift", {type: "keyup"});
+        },
+        check () {
+        },
+      },
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "g",
+                "clauses":
+                [
+                  { "length": 1, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+                ]
+              },
+              "caret": { "start": 1, "length": 0 }
+            });
+        },
+        check () {
+          is(getValue(aEditor), "ABgef", description + "Typing 'g' next to AB");
+        },
+      },
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "gh",
+                "clauses":
+                [
+                  { "length": 2, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+                ]
+              },
+              "caret": { "start": 2, "length": 0 }
+            });
+        },
+        check () {
+          is(getValue(aEditor), "ABghef", description + "Typing 'h' next to ABg");
+        },
+      },
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "ghi",
+                "clauses":
+                [
+                  { "length": 3, "attr": COMPOSITION_ATTR_RAW_CLAUSE }
+                ]
+              },
+              "caret": { "start": 3, "length": 0 }
+            });
+        },
+        check () {
+          is(getValue(aEditor), "ABghief", description + "Typing 'i' next to ABgh");
+        },
+      },
+      { test () {
+          synthesizeCompositionChange(
+            { "composition":
+              { "string": "GHI",
+                "clauses":
+                [
+                  { "length": 3, "attr": COMPOSITION_ATTR_SELECTED_CLAUSE }
+                ]
+              },
+              "caret": { "start": 3, "length": 0 }
+            });
+        },
+        check () {
+          is(getValue(aEditor), "ABGHIef", description + "Convert 'ghi' to 'GHI'");
+        },
+      },
+      { test () {
+          // Commit composition
+          synthesizeComposition({ type: "compositioncommitasis" });
+        },
+        check () {
+          is(getValue(aEditor), "ABGHIef", description + "Commit 'GHI'");
+        },
+      },
+    ];
+
+    function doReframe(aEvent)
+    {
+      aEvent.target.style.overflow =
+        aEvent.target.style.overflow != "hidden" ? "hidden" : "auto";
+    }
+    aEditor.focus();
+    aEditor.addEventListener(aEventType, doReframe);
+
+    for (const currentTest of tests) {
+      currentTest.test();
+      await waitForEventLoops(20);
+      currentTest.check();
+      await waitForTick();
+    }
+
+    await new Promise(resolve => {
+      aEditor.style.overflow = "auto";
+      aEditor.removeEventListener(aEventType, doReframe);
+      requestAnimationFrame(() => { SimpleTest.executeSoon(resolve); });
+    });
+  }
+
+  // TODO: Add "beforeinput" case.
+  input.value = "";
+  await runEditorReframeTest(input, window, "input");
+  input.value = "";
+  await runEditorReframeTest(input, window, "compositionupdate");
+  textarea.value = "";
+  await runEditorReframeTest(textarea, window, "input");
+  textarea.value = "";
+  await runEditorReframeTest(textarea, window, "compositionupdate");
+  contenteditable.innerHTML = "";
+  await runEditorReframeTest(contenteditable, windowOfContenteditable, "input");
+  contenteditable.innerHTML = "";
+  await runEditorReframeTest(contenteditable, windowOfContenteditable, "compositionupdate");
+}
+
+async function runIMEContentObserverTest()
+{
+  let notifications = [];
+  let onReceiveNotifications = null;
+  function callback(aTIP, aNotification)
+  {
+    if (aNotification.type != "notify-end-input-transaction") {
+      notifications.push(aNotification);
+    }
+    switch (aNotification.type) {
+      case "request-to-commit":
+        aTIP.commitComposition();
+        break;
+      case "request-to-cancel":
+        aTIP.cancelComposition();
+        break;
+    }
+    if (onReceiveNotifications) {
+      let resolve = onReceiveNotifications;
+      onReceiveNotifications = null;
+      SimpleTest.executeSoon(() => {
+        resolve();
+      });
+    }
+    return true;
+  }
+
+  function dumpUnexpectedNotifications(aDescription, aExpectedCount)
+  {
+    if (notifications.length <= aExpectedCount) {
+      return;
+    }
+    for (let i = aExpectedCount; i < notifications.length; i++) {
+      ok(false,
+         aDescription + " caused unexpected notification: " + notifications[i].type);
+    }
+  }
+
+  function promiseReceiveNotifications()
+  {
+    notifications = [];
+    return new Promise(resolve => {
+      onReceiveNotifications = resolve;
+    });
+  }
+
+  function flushNotifications()
+  {
+    return new Promise(resolve => {
+      // FYI: Dispatching non-op keyboard events causes forcibly flushing pending
+      //      notifications.
+      synthesizeKey("KEY_Unidentified", { code: "" });
+      SimpleTest.executeSoon(()=>{
+        notifications = [];
+        resolve();
+      });
+    });
+  }
+
+  function ensureToRemovePrecedingPositionChangeNotification(aDescription)
+  {
+    if (!notifications.length) {
+      return;
+    }
+    if (notifications[0].type != "notify-position-change") {
+      return;
+    }
+    // Sometimes, notify-position-change is notified first separately if
+    // the operation causes scroll or something.  Tests can ignore this.
+    ok(true, "notify-position-change", aDescription + "Unnecessary notify-position-change occurred, ignoring it");
+    notifications.shift();
+  }
+
+  // Bug 1374057 - On ubuntu 16.04 there are notify-position-change events that are
+  // recorded after all the other events so we remove them through this function.
+  function ensureToRemovePostPositionChangeNotification(aDescription, expectedCount)
+  {
+    if (!notifications.length) {
+      return;
+    }
+    if (notifications.length <= expectedCount) {
+      return;
+    }
+    if (notifications[notifications.length-1].type != "notify-position-change") {
+      return;
+    }
+    ok(true, "notify-position-change", aDescription + "Unnecessary notify-position-change occurred, ignoring it");
+    notifications.pop();
+  }
+
+  function getNativeText(aXPText)
+  {
+    if (kLF == "\n") {
+      return aXPText;
+    }
+    return aXPText.replace(/\n/g, kLF);
+  }
+
+  function checkPositionChangeNotification(aNotification, aDescription)
+  {
+    is(!aNotification || aNotification.type, "notify-position-change",
+       aDescription + " should cause position change notification");
+  }
+
+  function checkSelectionChangeNotification(aNotification, aDescription, aExpected)
+  {
+    is(!aNotification || aNotification.type, "notify-selection-change",
+       aDescription + " should cause selection change notification");
+    if (!aNotification || (aNotification.type != "notify-selection-change")) {
+      return;
+    }
+    is(aNotification.offset, aExpected.offset,
+       aDescription + " should cause selection change notification whose offset is " + aExpected.offset);
+    is(aNotification.text, aExpected.text,
+       aDescription + " should cause selection change notification whose text is '" + aExpected.text + "'");
+    is(aNotification.collapsed, !aExpected.text.length,
+       aDescription + " should cause selection change notification whose collapsed is " + (!aExpected.text.length));
+    is(aNotification.length, aExpected.text.length,
+       aDescription + " should cause selection change notification whose length is " + aExpected.text.length);
+    is(aNotification.reversed, aExpected.reversed || false,
+       aDescription + " should cause selection change notification whose reversed is " + (aExpected.reversed || false));
+    is(aNotification.writingMode, aExpected.writingMode || "horizontal-tb",
+       aDescription + " should cause selection change notification whose writingMode is '" + (aExpected.writingMode || "horizontal-tb"));
+  }
+
+  function checkTextChangeNotification(aNotification, aDescription, aExpected)
+  {
+    is(!aNotification || aNotification.type, "notify-text-change",
+       aDescription + " should cause text change notification");
+    if (!aNotification || aNotification.type != "notify-text-change") {
+      return;
+    }
+    is(aNotification.offset, aExpected.offset,
+       aDescription + " should cause text change notification whose offset is " + aExpected.offset);
+    is(aNotification.removedLength, aExpected.removedLength,
+       aDescription + " should cause text change notification whose removedLength is " + aExpected.removedLength);
+    is(aNotification.addedLength, aExpected.addedLength,
+       aDescription + " should cause text change notification whose addedLength is " + aExpected.addedLength);
+  }
+
+  async function testWithPlaintextEditor(aDescription, aElement, aTestLineBreaker)
+  {
+    aElement.value = "";
+    aElement.blur();
+    let doc = aElement.ownerDocument;
+    let win = doc.defaultView;
+    aElement.focus();
+    await flushNotifications();
+
+    // "a[]"
+    let description = aDescription + "typing 'a'";
+    let waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("a", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 0, removedLength: 0, addedLength: 1 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 1, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "ab[]"
+    description = aDescription + "typing 'b'";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("b", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 1, removedLength: 0, addedLength: 1 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 2, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "abc[]"
+    description = aDescription + "typing 'c'";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("c", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 2, removedLength: 0, addedLength: 1 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 3, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "ab[c]"
+    description = aDescription + "selecting 'c' with pressing Shift+ArrowLeft";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 2, text: "c", reversed: true });
+    ensureToRemovePostPositionChangeNotification(description, 1);
+    dumpUnexpectedNotifications(description, 1);
+
+    // "a[bc]"
+    description = aDescription + "selecting 'bc' with pressing Shift+ArrowLeft";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 1, text: "bc", reversed: true });
+    ensureToRemovePostPositionChangeNotification(description, 1);
+    dumpUnexpectedNotifications(description, 1);
+
+    // "[abc]"
+    description = aDescription + "selecting 'bc' with pressing Shift+ArrowLeft";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 0, text: "abc", reversed: true });
+    ensureToRemovePostPositionChangeNotification(description, 1);
+    dumpUnexpectedNotifications(description, 1);
+
+    // "[]abc"
+    description = aDescription + "collapsing selection to the left-most with pressing ArrowLeft";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowLeft", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 0, text: "" });
+    ensureToRemovePostPositionChangeNotification(description, 1);
+    dumpUnexpectedNotifications(description, 1);
+
+    // "[a]bc"
+    description = aDescription + "selecting 'a' with pressing Shift+ArrowRight";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowRight", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 0, text: "a" });
+    ensureToRemovePostPositionChangeNotification(description, 1);
+    dumpUnexpectedNotifications(description, 1);
+
+    // "[ab]c"
+    description = aDescription + "selecting 'ab' with pressing Shift+ArrowRight";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowRight", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 0, text: "ab" });
+    ensureToRemovePostPositionChangeNotification(description, 1);
+    dumpUnexpectedNotifications(description, 1);
+
+    // "[]c"
+    description = aDescription + "deleting 'ab' with pressing Delete";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 0, removedLength: 2, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 0, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "[]"
+    description = aDescription + "deleting following 'c' with pressing Delete";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 0, removedLength: 1, addedLength: 0 });
+    checkPositionChangeNotification(notifications[1], description);
+    ensureToRemovePostPositionChangeNotification(description, 2);
+    dumpUnexpectedNotifications(description, 2);
+
+    // "abc[]"
+    synthesizeKey("a", {}, win, callback);
+    synthesizeKey("b", {}, win, callback);
+    synthesizeKey("c", {}, win, callback);
+    await flushNotifications();
+
+    // "ab[]"
+    description = aDescription + "deleting 'c' with pressing Backspace";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Backspace", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 2, removedLength: 1, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 2, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "[ab]"
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await flushNotifications();
+
+    // "[]"
+    description = aDescription + "deleting 'ab' with pressing Backspace";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Backspace", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 0, removedLength: 2, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 0, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "abcd[]"
+    synthesizeKey("a", {}, win, callback);
+    synthesizeKey("b", {}, win, callback);
+    synthesizeKey("c", {}, win, callback);
+    synthesizeKey("d", {}, win, callback);
+    await flushNotifications();
+
+    // "a[bc]d"
+    synthesizeKey("KEY_ArrowLeft", {}, win, callback);
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await flushNotifications();
+
+    // "a[]d"
+    description = aDescription + "deleting 'bc' with pressing Backspace";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Backspace", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 1, removedLength: 2, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 1, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "a[bc]d"
+    synthesizeKey("b", {}, win, callback);
+    synthesizeKey("c", {}, win, callback);
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await flushNotifications();
+
+    // "aB[]d"
+    description = aDescription + "replacing 'bc' with 'B' with pressing Shift+B";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("B", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 1, removedLength: 2, addedLength: 1 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 2, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    if (!aTestLineBreaker) {
+      return;
+    }
+
+    // "aB\n[]d"
+    description = aDescription + "inserting a line break after 'B' with pressing Enter";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Enter", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 2, removedLength: 0, addedLength: kLFLen });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("aB\n").length, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "aB[]d"
+    description = aDescription + "removing a line break after 'B' with pressing Backspace";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Backspace", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 2, removedLength: kLFLen, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 2, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "a[B]d"
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await flushNotifications();
+
+    // "a\n[]d"
+    description = aDescription + "replacing 'B' with a line break with pressing Enter";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Enter", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 1, removedLength: 1, addedLength: kLFLen });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("a\n").length, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "a[\n]d"
+    description = aDescription + "selecting '\n' with pressing Shift+ArrowLeft";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 1, text: kLF, reversed: true });
+    ensureToRemovePostPositionChangeNotification(description, 1);
+    dumpUnexpectedNotifications(description, 1);
+
+    // "a[]d"
+    description = aDescription + "removing selected '\n' with pressing Delete";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 1, removedLength: kLFLen, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 1, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // ab\ncd\nef\ngh\n[]
+    description = aDescription + "setting the value property to 'ab\ncd\nef\ngh\n'";
+    waitNotifications = promiseReceiveNotifications();
+    aElement.value = "ab\ncd\nef\ngh\n";
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 0, removedLength: 2, addedLength: getNativeText("ab\ncd\nef\ngh\n").length });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("ab\ncd\nef\ngh\n").length, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+
+    // []
+    description = aDescription + "setting the value property to ''";
+    waitNotifications = promiseReceiveNotifications();
+    aElement.value = "";
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 0, removedLength: getNativeText("ab\ncd\nef\ngh\n").length, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 0, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    ensureToRemovePostPositionChangeNotification(description, 3);
+    dumpUnexpectedNotifications(description, 3);
+  }
+
+  async function testWithHTMLEditor(aDescription, aElement, aDefaultParagraphSeparator)
+  {
+    let doc = aElement.ownerDocument;
+    let win = doc.defaultView;
+    let sel = doc.getSelection();
+    let inDesignMode = doc.designMode == "on";
+    let offsetAtStart = 0;
+    let offsetAtContainer = 0;
+    let isDefaultParagraphSeparatorBlock = aDefaultParagraphSeparator != "br";
+    doc.execCommand("defaultParagraphSeparator", false, aDefaultParagraphSeparator);
+
+    // "[]", "<p>[]</p>" or "<div>[]</div>"
+    switch (aDefaultParagraphSeparator) {
+      case "br":
+        aElement.innerHTML = "";
+        break;
+      case "p":
+      case "div":
+        aElement.innerHTML = "<" + aDefaultParagraphSeparator + "></" + aDefaultParagraphSeparator + ">";
+        sel.collapse(aElement.firstChild, 0);
+        offsetAtContainer = offsetAtStart + kLFLen;
+        break;
+      default:
+        ok(false, aDescription + "aDefaultParagraphSeparator is illegal value");
+        await flushNotifications();
+        return;
+    }
+
+    if (inDesignMode) {
+      win.focus();
+    } else {
+      aElement.focus();
+    }
+    await flushNotifications();
+
+    // "a[]"
+    let description = aDescription + "typing 'a'";
+    let waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("a", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 0 + offsetAtContainer, removedLength: 0, addedLength: 1 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 1 + offsetAtContainer, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "ab[]"
+    description = aDescription + "typing 'b'";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("b", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 1 + offsetAtContainer, removedLength: 0, addedLength: 1 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 2 + offsetAtContainer, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "abc[]"
+    description = aDescription + "typing 'c'";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("c", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 2 + offsetAtContainer, removedLength: 0, addedLength: 1 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 3 + offsetAtContainer, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "ab[c]"
+    description = aDescription + "selecting 'c' with pressing Shift+ArrowLeft";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 2 + offsetAtContainer, text: "c", reversed: true });
+    dumpUnexpectedNotifications(description, 1);
+
+    // "a[bc]"
+    description = aDescription + "selecting 'bc' with pressing Shift+ArrowLeft";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 1 + offsetAtContainer, text: "bc", reversed: true });
+    dumpUnexpectedNotifications(description, 1);
+
+    // "[abc]"
+    description = aDescription + "selecting 'bc' with pressing Shift+ArrowLeft";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 0 + offsetAtContainer, text: "abc", reversed: true });
+    dumpUnexpectedNotifications(description, 1);
+
+    // "[]abc"
+    description = aDescription + "collapsing selection to the left-most with pressing ArrowLeft";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowLeft", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 0 + offsetAtContainer, text: "" });
+    dumpUnexpectedNotifications(description, 1);
+
+    // "[a]bc"
+    description = aDescription + "selecting 'a' with pressing Shift+ArrowRight";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowRight", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 0 + offsetAtContainer, text: "a" });
+    dumpUnexpectedNotifications(description, 1);
+
+    // "[ab]c"
+    description = aDescription + "selecting 'ab' with pressing Shift+ArrowRight";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowRight", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 0 + offsetAtContainer, text: "ab" });
+    dumpUnexpectedNotifications(description, 1);
+
+    // "[]c"
+    description = aDescription + "deleting 'ab' with pressing Delete";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 0 + offsetAtContainer, removedLength: 2, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 0 + offsetAtContainer, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "[]"
+    description = aDescription + "deleting following 'c' with pressing Delete";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 0 + offsetAtContainer, removedLength: 1, addedLength: kLFLen });
+    checkPositionChangeNotification(notifications[1], description);
+    dumpUnexpectedNotifications(description, 2);
+
+    // "abc[]"
+    synthesizeKey("a", {}, win, callback);
+    synthesizeKey("b", {}, win, callback);
+    synthesizeKey("c", {}, win, callback);
+    await flushNotifications();
+
+    // "ab[]"
+    description = aDescription + "deleting 'c' with pressing Backspace";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Backspace", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 2 + offsetAtContainer, removedLength: 1, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 2 + offsetAtContainer, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "[ab]"
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await flushNotifications();
+
+    // "[]"
+    description = aDescription + "deleting 'ab' with pressing Backspace";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Backspace", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 0 + offsetAtContainer, removedLength: 2, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 0 + offsetAtContainer, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "abcd[]"
+    synthesizeKey("a", {}, win, callback);
+    synthesizeKey("b", {}, win, callback);
+    synthesizeKey("c", {}, win, callback);
+    synthesizeKey("d", {}, win, callback);
+    await flushNotifications();
+
+    // "a[bc]d"
+    synthesizeKey("KEY_ArrowLeft", {}, win, callback);
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await flushNotifications();
+
+    // "a[]d"
+    description = aDescription + "deleting 'bc' with pressing Backspace";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Backspace", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 1 + offsetAtContainer, removedLength: 2, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 1 + offsetAtContainer, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "a[bc]d"
+    synthesizeKey("b", {}, win, callback);
+    synthesizeKey("c", {}, win, callback);
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await flushNotifications();
+
+    // "aB[]d"
+    description = aDescription + "replacing 'bc' with 'B' with pressing Shift+B";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("B", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 1 + offsetAtContainer, removedLength: 2, addedLength: 1 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 2 + offsetAtContainer, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "aB<br>[]d" or "<block>aB</block><block>[]d</block>"
+    description = aDescription + "inserting a line break after 'B' with pressing Enter";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Enter", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    if (isDefaultParagraphSeparatorBlock) {
+      // Splitting current block causes removing "d</block>" and inserting "</block><block>d</block>".
+      checkTextChangeNotification(notifications[0], description, {
+        offset: offsetAtContainer + "aB".length,
+        removedLength: getNativeText("d\n").length,
+        addedLength: getNativeText("\nd\n").length,
+      });
+    } else {
+      // Inserting <br> causes removing "d" and inserting "<br>d"
+      checkTextChangeNotification(notifications[0], description, {
+        offset: offsetAtContainer + "aB".length,
+        removedLength: "d".length,
+        addedLength: getNativeText("\nd").length,
+      });
+    }
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("aB\n").length + offsetAtContainer, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "aB[]d"
+    description = aDescription + "removing a line break after 'B' with pressing Backspace";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Backspace", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    if (isDefaultParagraphSeparatorBlock) {
+      // Joining two blocks causes removing "aB</block><block>d</block>" and inserting "aBd</block>"
+      checkTextChangeNotification(notifications[0], description, {
+        offset: offsetAtContainer,
+        removedLength: getNativeText("aB\nd\n").length,
+        addedLength: getNativeText("aBd\n").length,
+      });
+      checkSelectionChangeNotification(notifications[1], description, { offset: 2 + offsetAtContainer, text: "" });
+      checkPositionChangeNotification(notifications[2], description);
+      dumpUnexpectedNotifications(description, 3);
+    } else {
+      checkTextChangeNotification(notifications[0], description, {
+        offset: offsetAtContainer + "aB".length,
+        removedLength: kLFLen,
+        addedLength: 0,
+      });
+      is(notifications.length, 3, description + " should cause 3 notifications");
+      is(notifications[1] && notifications[1].type, "notify-selection-change", description + " should cause selection change notification");
+      is(notifications[2] && notifications[2].type, "notify-position-change", description + " should cause position change notification");
+    }
+
+    // "a[B]d"
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await flushNotifications();
+
+    // "a<br>[]d" or "<block>a</block><block>[]d</block>"
+    description = aDescription + "replacing 'B' with a line break with pressing Enter";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Enter", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    if (isDefaultParagraphSeparatorBlock) {
+      // Splitting current block causes removing "Bd</block>" and inserting "</block><block>d</block>".
+      checkTextChangeNotification(notifications[0], description, {
+        offset: offsetAtContainer + "a".length,
+        removedLength: getNativeText("Bd\n").length,
+        addedLength: getNativeText("\nd\n").length,
+      });
+    } else {
+      checkTextChangeNotification(notifications[0], description, {
+        offset: offsetAtContainer + "a".length,
+        removedLength: "B".length,
+        addedLength: kLFLen,
+      });
+    }
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("a\n").length + offsetAtContainer, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "a[<br>]d" or "<block>a[</block><block>]d</block>"
+    description = aDescription + "selecting '\\n' with pressing Shift+ArrowLeft";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_ArrowLeft", {shiftKey: true}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkSelectionChangeNotification(notifications[0], description, { offset: 1 + offsetAtContainer, text: kLF, reversed: true });
+    dumpUnexpectedNotifications(description, 1);
+
+    // "a[]d"
+    description = aDescription + "removing selected '\\n' with pressing Delete";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    if (isDefaultParagraphSeparatorBlock) {
+      // Joining the blocks causes removing "a</block><block>d</block>" and inserting "<block>ad</block>".
+      checkTextChangeNotification(notifications[0], description, {
+        offset: offsetAtContainer,
+        removedLength: getNativeText("a\nd\n").length,
+        addedLength: getNativeText("ad\n").length,
+      });
+    } else {
+      checkTextChangeNotification(notifications[0], description, {
+        offset: offsetAtContainer + "a".length,
+        removedLength: kLFLen,
+        addedLength: 0,
+      });
+    }
+    checkSelectionChangeNotification(notifications[1], description, { offset: 1 + offsetAtContainer, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // aElement.innerHTML = "<div>1<div>2<div>3</div>4</div>5</div>"
+    description = aDescription + "inserting HTML which has nested block elements";
+    waitNotifications = promiseReceiveNotifications();
+    aElement.innerHTML = "<div>1<div>2<div>3</div>4</div>5</div>";
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    // There is <br> after the end of the line.  Therefore, removed length includes a line breaker length.
+    if (isDefaultParagraphSeparatorBlock) {
+      checkTextChangeNotification(notifications[0], description, { offset: 0 + offsetAtContainer - kLFLen, removedLength: getNativeText("\nad\n").length, addedLength: getNativeText("\n1\n2\n345").length });
+    } else {
+      checkTextChangeNotification(notifications[0], description, { offset: 0 + offsetAtContainer, removedLength: 2 + kLFLen, addedLength: getNativeText("\n1\n2\n345").length });
+    }
+    checkSelectionChangeNotification(notifications[1], description, { offset: 0, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "<div>1[<div>2<div>3</div>4</div>]5</div>" and removing selection
+    sel.setBaseAndExtent(aElement.firstChild.firstChild, 1, aElement.firstChild.childNodes.item(2), 0);
+    await flushNotifications();
+    description = aDescription + "deleting child nodes with pressing Delete key";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    is(aElement.innerHTML, "<div>15</div>", description + " should remove '<div>2<div>3</div>4</div>'");
+    checkTextChangeNotification(notifications[0], description, { offset: getNativeText("\n1").length + offsetAtStart, removedLength: getNativeText("\n2\n34").length, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("\n1").length + offsetAtStart, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "<div>1[<div>2<div>3</div>]4</div>5</div>" and removing selection
+    aElement.innerHTML = "<div>1<div>2<div>3</div>4</div>5</div>";
+    sel.setBaseAndExtent(aElement.firstChild.firstChild, 1, aElement.firstChild.childNodes.item(1).childNodes.item(2), 0);
+    await flushNotifications();
+    description = aDescription + "deleting child nodes (partially #1) with pressing Delete key";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    is(aElement.innerHTML, "<div>145</div>", description + " should remove '<div>2<div>3</div></div>'");
+    // It causes removing '<div>2<div>3</div>4</div>' and inserting '4'.
+    checkTextChangeNotification(notifications[0], description, { offset: getNativeText("\n1").length + offsetAtStart, removedLength: getNativeText("\n2\n34").length, addedLength: 1 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("\n1").length + offsetAtStart, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "<div>1[<div>2<div>]3</div>4</div>5</div>" and removing selection
+    aElement.innerHTML = "<div>1<div>2<div>3</div>4</div>5</div>";
+    sel.setBaseAndExtent(aElement.firstChild.firstChild, 1, aElement.firstChild.childNodes.item(1).childNodes.item(1).firstChild, 0);
+    await flushNotifications();
+    description = aDescription + "deleting child nodes (partially #2) with pressing Delete key";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    is(aElement.innerHTML, "<div>13<div>4</div>5</div>", description + " should remove '<div>2</div>'");
+    // It causes removing '1<div>2<div>3</div></div>' and inserting '13<div>'.
+    checkTextChangeNotification(notifications[0], description, { offset: kLFLen + offsetAtStart, removedLength: getNativeText("1\n2\n3").length, addedLength: getNativeText("13\n").length });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("\n1").length + offsetAtStart, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "<div>1<div>2<div>3[</div>4</div>]5</div>" and removing selection
+    aElement.innerHTML = "<div>1<div>2<div>3</div>4</div>5</div>";
+    sel.setBaseAndExtent(aElement.firstChild.childNodes.item(1).childNodes.item(1).firstChild, 1, aElement.firstChild.childNodes.item(2), 0);
+    await flushNotifications();
+    description = aDescription + "deleting child nodes (partially #3) with pressing Delete key";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    is(aElement.innerHTML, "<div>1<div>2<div>35</div></div></div>", description + " should remove '4'");
+    // It causes removing '45' and inserting '5'.
+    checkTextChangeNotification(notifications[0], description, { offset: getNativeText("\n1\n2\n3").length + offsetAtStart, removedLength: 2, addedLength: 1 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("\n1\n2\n3").length + offsetAtStart, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // aElement.innerHTML = "<div>1<div>2<div>3</div>4</div>5<div>6<div>7</div>8</div>9</div>"
+    description = aDescription + "inserting HTML which has a pair of nested block elements";
+    waitNotifications = promiseReceiveNotifications();
+    aElement.innerHTML = "<div>1<div>2<div>3</div>4</div>5<div>6<div>7</div>8</div>9</div>";
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    checkTextChangeNotification(notifications[0], description, { offset: 0 + offsetAtStart, removedLength: getNativeText("\n1\n2\n35").length, addedLength: getNativeText("\n1\n2\n345\n6\n789").length });
+    checkSelectionChangeNotification(notifications[1], description, { offset: 0 + offsetAtStart, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "<div>1<div>2<div>3[</div>4</div>5<div>6<div>]7</div>8</div>9</div>" and removing selection
+    sel.setBaseAndExtent(aElement.firstChild.childNodes.item(1).childNodes.item(1).firstChild, 1, aElement.firstChild.childNodes.item(3).childNodes.item(1).firstChild, 0);
+    await flushNotifications();
+    description = aDescription + "deleting child nodes (between same level descendants) with pressing Delete key";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    is(aElement.innerHTML, "<div>1<div>2<div>37</div></div><div>8</div>9</div>", description + " should remove '456<div>7'");
+    // It causes removing '<div>3</div>4</div>5<div>6<div>7</div>' and inserting '<div>37</div><div>'.
+    checkTextChangeNotification(notifications[0], description, { offset: getNativeText("\n1\n2").length + offsetAtStart, removedLength: getNativeText("\n345\n6\n7").length, addedLength: getNativeText("\n37\n").length });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("\n1\n2\n3").length + offsetAtStart, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "<div>1<div>2[<div>3</div>4</div>5<div>6<div>]7</div>8</div>9</div>" and removing selection
+    aElement.innerHTML = "<div>1<div>2<div>3</div>4</div>5<div>6<div>7</div>8</div>9</div>";
+    sel.setBaseAndExtent(aElement.firstChild.childNodes.item(1).firstChild, 1, aElement.firstChild.childNodes.item(3).childNodes.item(1).firstChild, 0);
+    await flushNotifications();
+    description = aDescription + "deleting child nodes (between different level descendants #1) with pressing Delete key";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    is(aElement.innerHTML, "<div>1<div>27</div><div>8</div>9</div>", description + " should remove '<div>2<div>3</div>4</div>5<div>6<div>7</div>'");
+    // It causes removing '<div>2<div>3</div>4</div>5<div>6<div>7</div>' and inserting '<div>27</div>'.
+    checkTextChangeNotification(notifications[0], description, { offset: getNativeText("\n1").length + offsetAtStart, removedLength: getNativeText("\n2\n345\n6\n7").length, addedLength: getNativeText("\n27\n").length });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("\n1\n2").length + offsetAtStart, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "<div>1<div>2[<div>3</div>4</div>5<div>6<div>7</div>8</div>]9</div>" and removing selection
+    aElement.innerHTML = "<div>1<div>2<div>3</div>4</div>5<div>6<div>7</div>8</div>9</div>";
+    sel.setBaseAndExtent(aElement.firstChild.childNodes.item(1).firstChild, 1, aElement.firstChild.childNodes.item(4), 0);
+    await flushNotifications();
+    description = aDescription + "deleting child nodes (between different level descendants #2) with pressing Delete key";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    is(aElement.innerHTML, "<div>1<div>29</div></div>", description + " should remove '<div>3</div>4</div>5<div>6<div>7</div>8</div>'");
+    // It causes removing '<div>3</div>4</div>5</div>6<div>7</div>8</div>9' and inserting '9</div>'.
+    checkTextChangeNotification(notifications[0], description, { offset: getNativeText("\n1\n2").length + offsetAtStart, removedLength: getNativeText("\n345\n6\n789").length, addedLength: 1 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("\n1\n2").length + offsetAtStart, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "<div>1<div>2<div>3[</div>4</div>5<div>]6<div>7</div>8</div>9</div>" and removing selection
+    aElement.innerHTML = "<div>1<div>2<div>3</div>4</div>5<div>6<div>7</div>8</div>9</div>";
+    sel.setBaseAndExtent(aElement.firstChild.childNodes.item(1).childNodes.item(1).firstChild, 1, aElement.firstChild.childNodes.item(3).firstChild, 0);
+    await flushNotifications();
+    description = aDescription + "deleting child nodes (between different level descendants #3) with pressing Delete key";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    is(aElement.innerHTML, "<div>1<div>2<div>36<div>7</div>8</div></div>9</div>", description + " should remove '<div>36<div>7</div>8</div>'");
+    // It causes removing '<div>3</div>4</div>5<div>6<div>7</div>8</div>' and inserting '<div>36<div>7</div>8</div>'.
+    checkTextChangeNotification(notifications[0], description, { offset: getNativeText("\n1\n2").length + offsetAtStart, removedLength: getNativeText("\n345\n6\n78").length, addedLength: getNativeText("\n36\n78").length });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("\n1\n2\n3").length + offsetAtStart, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "<div>1<div>2<div>3[</div>4</div>5<div>6<div>7</div>8</div>]9</div>" and removing selection
+    aElement.innerHTML = "<div>1<div>2<div>3</div>4</div>5<div>6<div>7</div>8</div>9</div>";
+    sel.setBaseAndExtent(aElement.firstChild.childNodes.item(1).childNodes.item(1).firstChild, 1, aElement.firstChild.childNodes.item(4), 0);
+    await flushNotifications();
+    description = aDescription + "deleting child nodes (between different level descendants #4) with pressing Delete key";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Delete", {}, win, callback);
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    is(aElement.innerHTML, "<div>1<div>2<div>39</div></div></div>", description + " should remove '</div>4</div>5<div>6<div>7</div>8</div>'");
+    // It causes removing '</div>4</div>5<div>6<div>7</div>8</div>' and inserting '<div>36<div>7</div>8</div>'.
+    checkTextChangeNotification(notifications[0], description, { offset: getNativeText("\n1\n2\n3").length + offsetAtStart, removedLength: getNativeText("45\n6\n789").length, addedLength: getNativeText("9").length });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("\n1\n2\n3").length + offsetAtStart, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "<p>abc</p><p><br></p><p>{<br>}</p>" and removing second paragraph with DOM API
+    aElement.innerHTML = "<p>abc</p><p><br></p><p><br></p>";
+    sel.collapse(aElement.firstChild.nextSibling.nextSibling, 0);
+    await flushNotifications();
+    description = aDescription + "deleting previous paragraph with DOM API";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Unidentified", { code: "" }, win, callback);  // For setting the callback to recode notifications
+    aElement.firstChild.nextSibling.remove();
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    is(aElement.innerHTML, "<p>abc</p><p><br></p>", description + " the second paragraph should've been removed");
+    checkTextChangeNotification(notifications[0], description, { offset: getNativeText("\nabc").length + offsetAtStart, removedLength: getNativeText("\n\n").length, addedLength: 0 });
+    checkSelectionChangeNotification(notifications[1], description, { offset: getNativeText("\nabc\n").length + offsetAtStart, text: "" });
+    checkPositionChangeNotification(notifications[2], description);
+    dumpUnexpectedNotifications(description, 3);
+
+    // "<p>abc</p><p>{<br>}</p><p><br></p>" and removing last paragraph with DOM API
+    aElement.innerHTML = "<p>abc</p><p><br></p><p><br></p>";
+    sel.collapse(aElement.firstChild.nextSibling, 0);
+    await flushNotifications();
+    description = aDescription + "deleting next paragraph with DOM API";
+    waitNotifications = promiseReceiveNotifications();
+    synthesizeKey("KEY_Unidentified", { code: "" }, win, callback);  // For setting the callback to recode notifications
+    aElement.firstChild.nextSibling.nextSibling.remove();
+    await waitNotifications;
+    ensureToRemovePrecedingPositionChangeNotification();
+    is(aElement.innerHTML, "<p>abc</p><p><br></p>", description + " the last paragraph should've been removed");
+    checkTextChangeNotification(notifications[0], description, { offset: getNativeText("\nabc\n\n").length + offsetAtStart, removedLength: getNativeText("\n\n").length, addedLength: 0 });
+    checkPositionChangeNotification(notifications[1], description);
+    dumpUnexpectedNotifications(description, 2);
+  }
+
+  await testWithPlaintextEditor("runIMEContentObserverTest with input element: ", input, false);
+  await testWithPlaintextEditor("runIMEContentObserverTest with textarea element: ", textarea, true);
+  await testWithHTMLEditor("runIMEContentObserverTest with contenteditable (defaultParagraphSeparator is br): ", contenteditable, "br");
+  await testWithHTMLEditor("runIMEContentObserverTest with contenteditable (defaultParagraphSeparator is p): ", contenteditable, "p");
+  await testWithHTMLEditor("runIMEContentObserverTest with contenteditable (defaultParagraphSeparator is div): ", contenteditable, "div");
+  // XXX Due to the difference of HTML editor behavior between designMode and contenteditable,
+  //     testWithHTMLEditor() gets some unexpected behavior.  However, IMEContentObserver is
+  //     not depend on editor's detail.  So, we should investigate this issue later.  It's not
+  //     so important for now.
+  // await testWithHTMLEditor("runIMEContentObserverTest in designMode (defaultParagraphSeparator is br): ", iframe2.contentDocument.body, "br");
+  // await testWithHTMLEditor("runIMEContentObserverTest in designMode (defaultParagraphSeparator is p): ", iframe2.contentDocument.body, "p");
+  // await testWithHTMLEditor("runIMEContentObserverTest in designMode (defaultParagraphSeparator is div): ", iframe2.contentDocument.body, "div");
+}
+
+async function runPasswordMaskDelayTest() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["editor.password.mask_delay", 600],
+          ["editor.password.testing.mask_delay", true],
+         ],
+  });
+
+  let iframe5 = document.getElementById("iframe5");
+  let iframe6 = document.getElementById("iframe6");
+  let inputWindow = iframe5.contentWindow;
+  let passwordWindow = iframe6.contentWindow;
+
+  let inputElement = iframe5.contentDocument.getElementById("input");
+  let passwordElement = iframe6.contentDocument.getElementById("password");
+
+  const kMask = passwordElement.editor.passwordMask;
+
+  function promiseAllPasswordMasked() {
+    return new Promise(resolve => {
+      passwordElement.addEventListener("MozLastInputMasked", resolve, {once: true});
+    });
+  }
+
+  function checkSnapshots(aResult, aReference, aMatch, aDescription) {
+    let [correct, data1, data2] = compareSnapshots(aResult, aReference, true);
+    is(correct, aMatch, `${aDescription}\nREFTEST   IMAGE 1 (TEST): ${data1}\nREFTEST   IMAGE 2 (REFERENCE): ${data2}`);
+  }
+
+  // First character input
+  passwordElement.value = "";
+  passwordElement.focus();
+  let waitForMaskingLastInput = promiseAllPasswordMasked();
+  synthesizeKey("a");
+  let unmaskedResult = await snapshotWindow(passwordWindow, true);
+  await waitForMaskingLastInput;
+  let maskedResult = await snapshotWindow(passwordWindow, true);
+
+  inputElement.value = "a";
+  inputElement.focus();
+  inputElement.setSelectionRange(1, 1);
+  let unmaskedReference = await snapshotWindow(inputWindow, true);
+  inputElement.value = kMask;
+  inputElement.setSelectionRange(1, 1);
+  let maskedReference = await snapshotWindow(inputWindow, true);
+  checkSnapshots(unmaskedResult, unmaskedReference, true,
+                 "runPasswordMaskDelayTest(): first inputted character should be unmasked for a while");
+  checkSnapshots(maskedResult, maskedReference, true,
+                 "runPasswordMaskDelayTest(): first inputted character should be masked after a while");
+
+  // Second character input
+  passwordElement.value = "a";
+  passwordElement.focus();
+  passwordElement.setSelectionRange(1, 1);
+  waitForMaskingLastInput = promiseAllPasswordMasked();
+  synthesizeKey("b");
+  unmaskedResult = await snapshotWindow(passwordWindow, true);
+  await waitForMaskingLastInput;
+  maskedResult = await snapshotWindow(passwordWindow, true);
+
+  inputElement.value = `${kMask}b`;
+  inputElement.focus();
+  inputElement.setSelectionRange(2, 2);
+  unmaskedReference = await snapshotWindow(inputWindow, true);
+  inputElement.value = `${kMask}${kMask}`;
+  inputElement.setSelectionRange(2, 2);
+  maskedReference = await snapshotWindow(inputWindow, true);
+  checkSnapshots(unmaskedResult, unmaskedReference, true,
+                 "runPasswordMaskDelayTest(): second inputted character should be unmasked for a while");
+  checkSnapshots(maskedResult, maskedReference, true,
+                 "runPasswordMaskDelayTest(): second inputted character should be masked after a while");
+
+  // Typing new character should mask the previous unmasked characters
+  passwordElement.value = "ab";
+  passwordElement.focus();
+  passwordElement.setSelectionRange(2, 2);
+  waitForMaskingLastInput = promiseAllPasswordMasked();
+  synthesizeKey("c");
+  synthesizeKey("d");
+  unmaskedResult = await snapshotWindow(passwordWindow, true);
+  await waitForMaskingLastInput;
+  maskedResult = await snapshotWindow(passwordWindow, true);
+
+  inputElement.value = `${kMask}${kMask}${kMask}d`;
+  inputElement.focus();
+  inputElement.setSelectionRange(4, 4);
+  unmaskedReference = await snapshotWindow(inputWindow, true);
+  inputElement.value = `${kMask}${kMask}${kMask}${kMask}`;
+  inputElement.setSelectionRange(4, 4);
+  maskedReference = await snapshotWindow(inputWindow, true);
+  checkSnapshots(unmaskedResult, unmaskedReference, true,
+                 "runPasswordMaskDelayTest(): forth character input should mask the third character");
+  checkSnapshots(maskedResult, maskedReference, true,
+                 "runPasswordMaskDelayTest(): forth inputted character should be masked after a while");
+
+  // Typing middle of password should unmask the last input character
+  passwordElement.value = "abcd";
+  passwordElement.focus();
+  passwordElement.setSelectionRange(2, 2);
+  waitForMaskingLastInput = promiseAllPasswordMasked();
+  synthesizeKey("e");
+  unmaskedResult = await snapshotWindow(passwordWindow, true);
+  await waitForMaskingLastInput;
+  maskedResult = await snapshotWindow(passwordWindow, true);
+
+  inputElement.value = `${kMask}${kMask}e${kMask}${kMask}`;
+  inputElement.focus();
+  inputElement.setSelectionRange(3, 3);
+  unmaskedReference = await snapshotWindow(inputWindow, true);
+  inputElement.value = `${kMask}${kMask}${kMask}${kMask}${kMask}`;
+  inputElement.setSelectionRange(3, 3);
+  maskedReference = await snapshotWindow(inputWindow, true);
+  checkSnapshots(unmaskedResult, unmaskedReference, true,
+                 "runPasswordMaskDelayTest(): inserted character should be unmasked for a while");
+  checkSnapshots(maskedResult, maskedReference, true,
+                 "runPasswordMaskDelayTest(): inserted character should be masked after a while");
+
+  // Composition string should be unmasked for a while, and shouldn't be committed at masking
+  passwordElement.value = "ab";
+  passwordElement.focus();
+  passwordElement.setSelectionRange(1, 1);
+  waitForMaskingLastInput = promiseAllPasswordMasked();
+  synthesizeCompositionChange(
+    { composition:
+      { string: "c",
+        clauses: [{ length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 1, length: 0 },
+    });
+  unmaskedResult = await snapshotWindow(passwordWindow, true);
+  await waitForMaskingLastInput;
+  maskedResult = await snapshotWindow(passwordWindow, true);
+  is(getEditor(passwordElement).composing, true,
+     "runPasswordMaskDelayTest(): composition shouldn't be commited at masking the composing string #1");
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  inputElement.value = `${kMask}${kMask}`;
+  inputElement.focus();
+  inputElement.setSelectionRange(1, 1);
+  synthesizeCompositionChange(
+    { composition:
+      { string: "c",
+        clauses: [{ length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 1, length: 0 },
+    });
+  unmaskedReference = await snapshotWindow(inputWindow, true);
+  synthesizeCompositionChange(
+    { composition:
+      { string: kMask,
+        clauses: [{ length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 1, length: 0 },
+    });
+  maskedReference = await snapshotWindow(inputWindow, true);
+  checkSnapshots(unmaskedResult, unmaskedReference, true,
+                 "runPasswordMaskDelayTest(): composing character should be unmasked for a while");
+  checkSnapshots(maskedResult, maskedReference, true,
+                 "runPasswordMaskDelayTest(): composing character should be masked after a while");
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  // Updating composition string should unmask the composition string for a while
+  passwordElement.value = "ab";
+  passwordElement.focus();
+  passwordElement.setSelectionRange(1, 1);
+  waitForMaskingLastInput = promiseAllPasswordMasked();
+  synthesizeCompositionChange(
+    { composition:
+      { string: "c",
+        clauses: [{ length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 1, length: 0 },
+    });
+  await waitForMaskingLastInput;
+  waitForMaskingLastInput = promiseAllPasswordMasked();
+  synthesizeCompositionChange(
+    { composition:
+      { string: "d",
+        clauses: [{ length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 1, length: 0 },
+    });
+  unmaskedResult = await snapshotWindow(passwordWindow, true);
+  await waitForMaskingLastInput;
+  maskedResult = await snapshotWindow(passwordWindow, true);
+  is(getEditor(passwordElement).composing, true,
+     "runPasswordMaskDelayTest(): composition shouldn't be commited at masking the composing string #2");
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  inputElement.value = `${kMask}${kMask}`;
+  inputElement.focus();
+  inputElement.setSelectionRange(1, 1);
+  synthesizeCompositionChange(
+    { composition:
+      { string: "d",
+        clauses: [{ length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 1, length: 0 },
+    });
+  unmaskedReference = await snapshotWindow(inputWindow, true);
+  synthesizeCompositionChange(
+    { composition:
+      { string: kMask,
+        clauses: [{ length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 1, length: 0 },
+    });
+  maskedReference = await snapshotWindow(inputWindow, true);
+  checkSnapshots(unmaskedResult, unmaskedReference, true,
+                 "runPasswordMaskDelayTest(): updated composing character should be unmasked for a while");
+  checkSnapshots(maskedResult, maskedReference, true,
+                 "runPasswordMaskDelayTest(): updated composing character should be masked after a while");
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  // Composing multi-characters should be unmasked for a while.
+  passwordElement.value = "ab";
+  passwordElement.focus();
+  passwordElement.setSelectionRange(1, 1);
+  waitForMaskingLastInput = promiseAllPasswordMasked();
+  synthesizeCompositionChange(
+    { composition:
+      { string: "c",
+        clauses: [{ length: 1, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 1, length: 0 },
+    });
+  await waitForMaskingLastInput;
+  waitForMaskingLastInput = promiseAllPasswordMasked();
+  synthesizeCompositionChange(
+    { composition:
+      { string: "cd",
+        clauses: [{ length: 2, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 2, length: 0 },
+    });
+  unmaskedResult = await snapshotWindow(passwordWindow, true);
+  await waitForMaskingLastInput;
+  maskedResult = await snapshotWindow(passwordWindow, true);
+  is(getEditor(passwordElement).composing, true,
+     "runPasswordMaskDelayTest(): composition shouldn't be commited at masking the composing string #3");
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  inputElement.value = `${kMask}${kMask}`;
+  inputElement.focus();
+  inputElement.setSelectionRange(1, 1);
+  synthesizeCompositionChange(
+    { composition:
+      { string: "cd",
+        clauses: [{ length: 2, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 2, length: 0 },
+    });
+  unmaskedReference = await snapshotWindow(inputWindow, true);
+  synthesizeCompositionChange(
+    { composition:
+      { string: `${kMask}${kMask}`,
+        clauses: [{ length: 2, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 2, length: 0 },
+    });
+  maskedReference = await snapshotWindow(inputWindow, true);
+  checkSnapshots(unmaskedResult, unmaskedReference, true,
+                 "runPasswordMaskDelayTest(): all of composing string should be unmasked for a while");
+  checkSnapshots(maskedResult, maskedReference, true,
+                 "runPasswordMaskDelayTest(): all of composing string should be masked after a while");
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+
+  // Committing composition should make the commit string unmasked.
+  passwordElement.value = "ab";
+  passwordElement.focus();
+  passwordElement.setSelectionRange(1, 1);
+  waitForMaskingLastInput = promiseAllPasswordMasked();
+  synthesizeCompositionChange(
+    { composition:
+      { string: "cd",
+        clauses: [{ length: 2, attr: COMPOSITION_ATTR_RAW_CLAUSE }],
+      },
+      caret: { start: 2, length: 0 },
+    });
+  await waitForMaskingLastInput;
+  waitForMaskingLastInput = promiseAllPasswordMasked();
+  synthesizeComposition({ type: "compositioncommitasis", key: { key: "KEY_Enter" } });
+  unmaskedResult = await snapshotWindow(passwordWindow, true);
+  await waitForMaskingLastInput;
+  maskedResult = await snapshotWindow(passwordWindow, true);
+
+  inputElement.value = `${kMask}cd${kMask}`;
+  inputElement.focus();
+  inputElement.setSelectionRange(3, 3);
+  unmaskedReference = await snapshotWindow(inputWindow, true);
+  inputElement.value = `${kMask}${kMask}${kMask}${kMask}`;
+  inputElement.setSelectionRange(3, 3);
+  maskedReference = await snapshotWindow(inputWindow, true);
+  checkSnapshots(unmaskedResult, unmaskedReference, true,
+                 "runPasswordMaskDelayTest(): committed string should be unmasked for a while");
+  checkSnapshots(maskedResult, maskedReference, true,
+                 "runPasswordMaskDelayTest(): committed string should be masked after a while");
+}
+
+async function runInputModeTest()
+{
+  let result = [];
+
+  function handler(aEvent)
+  {
+    result.push(aEvent);
+  }
+
+  textarea.inputMode = "text";
+  textarea.value = "";
+  textarea.focus();
+
+  textarea.addEventListener("compositionupdate", handler, true);
+  textarea.addEventListener("compositionend", handler, true);
+
+  synthesizeCompositionChange({
+    composition: {string: "a ", clauses: [{length: 2, attr: COMPOSITION_ATTR_RAW_CLAUSE}]},
+  });
+
+  is(result[0].type, "compositionupdate", "Set initial composition for inputmode test");
+  result = [];
+
+  textarea.inputMode = "tel";
+  is(result.length, 0, "No compositonend event even if inputmode is updated");
+
+  // Clean up
+  synthesizeComposition({ type: "compositioncommitasis" });
+  textarea.inputMode = "";
+  textarea.value = "";
+  textarea.removeEventListener("compositionupdate", handler, true);
+  textarea.removeEventListener("compositionend", handler, true);
+}
+
+
+async function runTest()
+{
+  window.addEventListener("unload", window.arguments[0].SimpleTest.finish, {once: true, capture: true});
+
+  contenteditable = document.getElementById("iframe4").contentDocument.getElementById("contenteditable");
+  windowOfContenteditable = document.getElementById("iframe4").contentWindow;
+  textareaInFrame = iframe.contentDocument.getElementById("textarea");
+
+  contenteditableBySpan = document.getElementById("iframe7").contentDocument.getElementById("contenteditable");
+  windowOfContenteditableBySpan = document.getElementById("iframe7").contentWindow;
+
+  await runIMEContentObserverTest();
+  await runEditorReframeTests();
+  await runAsyncForceCommitTest();
+  await runRemoveContentTest();
+  await runPanelTest();
+  await runPasswordMaskDelayTest();
+  await runBug1584901Test();
+  await runInputModeTest();
+  await runCompositionTest();
+  await runCompositionCommitTest();
+  await runSetSelectionEventTest();
+
+  runUndoRedoTest();
+  runCompositionCommitAsIsTest();
+  runCompositionEventTest();
+  runCompositionTestWhoseTextNodeModified();
+  runQueryTextRectInContentEditableTest();
+  runCharAtPointTest(textarea, "textarea in the document");
+  runCharAtPointAtOutsideTest();
+  runQueryTextContentEventTest();
+  runQuerySelectionEventTest();
+  runQueryIMESelectionTest();
+  runQueryContentEventRelativeToInsertionPoint();
+  runQueryPasswordTest();
+  runCSSTransformTest();
+  runBug722639Test();
+  runBug1375825Test();
+  runBug1530649Test();
+  runBug1571375Test();
+  runBug1675313Test();
+  runCommitCompositionWithSpaceKey();
+  runCompositionWithSelectionChange();
+  runForceCommitTest();
+  runNestedSettingValue();
+  runBug811755Test();
+  runIsComposingTest();
+  runRedundantChangeTest();
+  runNotRedundantChangeTest();
+  runNativeLineBreakerTest();
+  runControlCharTest();
+  runFrameTest();
+  runMaxLengthTest();
+
+  window.close();
+}
+
+window.arguments[0].SimpleTest.waitForFocus(runTest, window);
+
+]]>
+</script>
+
+</window>
diff --git a/widget/tests/window_imestate_iframes.html b/widget/tests/window_imestate_iframes.html
new file mode 100644
index 0000000000..c8b182977f
--- /dev/null
+++ b/widget/tests/window_imestate_iframes.html
@@ -0,0 +1,358 @@
+<html>
+<head>
+  <title>Test for IME state controling and focus moving for iframes</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"></script>
+  <link rel="stylesheet" type="text/css"
+          href="chrome://mochikit/content/tests/SimpleTest/test.css" />
+  <style type="text/css">
+    iframe {
+      border: none;
+      height: 100px;
+    }
+  </style>
+</head>
+<body onunload="onUnload();">
+<p id="display">
+  <!-- Use input[readonly] because it isn't affected by the partial focus
+       movement on Mac -->
+  <input id="prev" readonly><br>
+  <iframe id="iframe_not_editable"
+          src="data:text/html,&lt;html&gt;&lt;body&gt;&lt;input id='editor'&gt;&lt;/body&gt;&lt;/html&gt;"></iframe><br>
+
+  <!-- Testing IME state and focus movement, the anchor elements cannot get focus -->
+  <iframe id="iframe_html"
+          src="data:text/html,&lt;html id='editor' contenteditable='true'&gt;&lt;body&gt;&lt;a href='about:blank'&gt;about:blank;&lt;/a&gt;&lt;/body&gt;&lt;/html&gt;"></iframe><br>
+  <iframe id="iframe_designMode"
+          src="data:text/html,&lt;body id='editor' onload='document.designMode=&quot;on&quot;;'&gt;&lt;a href='about:blank'&gt;about:blank;&lt;/a&gt;&lt;/body&gt;"></iframe><br>
+  <iframe id="iframe_body"
+          src="data:text/html,&lt;body id='editor' contenteditable='true'&gt;&lt;a href='about:blank'&gt;about:blank;&lt;/a&gt;&lt;/body&gt;"></iframe><br>
+  <iframe id="iframe_p"
+          src="data:text/html,&lt;body&gt;&lt;p id='editor' contenteditable='true'&gt;&lt;a href='about:blank'&gt;about:blank;&lt;/a&gt;&lt;/p&gt;&lt;/body&gt;"></iframe><br>
+
+  <input id="next" readonly><br>
+</p>
+<script class="testbody" type="application/javascript">
+
+window.opener.SimpleTest.waitForFocus(runTests, window);
+
+function ok(aCondition, aMessage) {
+  window.opener.SimpleTest.ok(aCondition, aMessage);
+}
+
+function is(aLeft, aRight, aMessage) {
+  window.opener.SimpleTest.is(aLeft, aRight, aMessage);
+}
+
+function onUnload() {
+  window.opener.onFinish();
+}
+
+var gFocusObservingElement = null;
+var gBlurObservingElement = null;
+
+function onFocus(aEvent) {
+  if (aEvent.target != gFocusObservingElement) {
+    return;
+  }
+  ok(gFocusObservingElement.willFocus,
+     "focus event is fired on unexpected element");
+  gFocusObservingElement.willFocus = false;
+}
+
+function onBlur(aEvent) {
+  if (aEvent.target != gBlurObservingElement) {
+    return;
+  }
+  ok(gBlurObservingElement.willBlur,
+     "blur event is fired on unexpected element");
+  gBlurObservingElement.willBlur = false;
+}
+
+function observeFocusBlur(aNextFocusedNode, aWillFireFocusEvent,
+                          aNextBlurredNode, aWillFireBlurEvent) {
+  if (gFocusObservingElement) {
+    if (gFocusObservingElement.willFocus) {
+      ok(false, "focus event was never fired on " + gFocusObservingElement);
+    }
+    gFocusObservingElement.removeEventListener("focus", onFocus, true);
+    gFocusObservingElement.willFocus = NaN;
+    gFocusObservingElement = null;
+  }
+  if (gBlurObservingElement) {
+    if (gBlurObservingElement.willBlur) {
+      ok(false, "blur event was never fired on " + gBlurObservingElement);
+    }
+    gBlurObservingElement.removeEventListener("blur", onBlur, true);
+    gBlurObservingElement.willBlur = NaN;
+    gBlurObservingElement = null;
+  }
+  if (aNextFocusedNode) {
+    gFocusObservingElement = aNextFocusedNode;
+    gFocusObservingElement.willFocus = aWillFireFocusEvent;
+    gFocusObservingElement.addEventListener("focus", onFocus, true);
+  }
+  if (aNextBlurredNode) {
+    gBlurObservingElement = aNextBlurredNode;
+    gBlurObservingElement.willBlur = aWillFireBlurEvent;
+    gBlurObservingElement.addEventListener("blur", onBlur, true);
+  }
+}
+
+function runTests() {
+  var utils = window.windowUtils;
+  var fm = Services.focus;
+
+  var iframe, editor, root;
+  var prev = document.getElementById("prev");
+  var next = document.getElementById("next");
+  var html = document.documentElement;
+
+  function resetFocusToInput(aDescription) {
+    observeFocusBlur(null, false, null, false);
+    prev.focus();
+    is(fm.focusedElement, prev,
+       "input#prev[readonly] element didn't get focus: " + aDescription);
+    is(utils.IMEStatus, utils.IME_STATUS_DISABLED,
+       "IME enabled on input#prev[readonly]: " + aDescription);
+  }
+
+  function resetFocusToParentHTML(aDescription) {
+    observeFocusBlur(null, false, null, false);
+    html.focus();
+    is(fm.focusedElement, html,
+       "Parent html element didn't get focus: " + aDescription);
+    is(utils.IMEStatus, utils.IME_STATUS_DISABLED,
+       "IME enabled on parent html element: " + aDescription);
+  }
+
+  function testTabKey(aForward,
+                      aNextFocusedNode, aWillFireFocusEvent,
+                      aNextBlurredNode, aWillFireBlurEvent,
+                      aIMEShouldBeEnabled, aTestingCaseDescription) {
+    observeFocusBlur(aNextFocusedNode, aWillFireFocusEvent,
+                     aNextBlurredNode, aWillFireBlurEvent);
+    synthesizeKey("VK_TAB", { shiftKey: !aForward });
+    var description = "Tab key test: ";
+    if (!aForward) {
+      description = "Shift-" + description;
+    }
+    description += aTestingCaseDescription + ": ";
+    is(fm.focusedElement, aNextFocusedNode,
+       description + "didn't move focus as expected");
+    is(utils.IMEStatus,
+       aIMEShouldBeEnabled ?
+         utils.IME_STATUS_ENABLED : utils.IME_STATUS_DISABLED,
+       description + "didn't set IME state as expected");
+  }
+
+  function testMouseClick(aNextFocusedNode, aWillFireFocusEvent,
+                          aWillAllNodeLostFocus,
+                          aNextBlurredNode, aWillFireBlurEvent,
+                          aIMEShouldBeEnabled, aTestingCaseDescription) {
+    observeFocusBlur(aNextFocusedNode, aWillFireFocusEvent,
+                     aNextBlurredNode, aWillFireBlurEvent);
+    // We're relying on layout inside the iframe being up to date, so make it so
+    iframe.contentDocument.documentElement.getBoundingClientRect();
+    synthesizeMouse(iframe, 10, 80, { });
+    var description = "Click test: " + aTestingCaseDescription + ": ";
+    is(fm.focusedElement, !aWillAllNodeLostFocus ? aNextFocusedNode : null,
+       description + "didn't move focus as expected");
+    is(utils.IMEStatus,
+       aIMEShouldBeEnabled ?
+         utils.IME_STATUS_ENABLED : utils.IME_STATUS_DISABLED,
+       description + "didn't set IME state as expected");
+  }
+
+  function testOnEditorFlagChange(aDescription, aIsInDesignMode) {
+    const kReadonly = Ci.nsIEditor.eEditorReadonlyMask;
+    var description = "testOnEditorFlagChange: " + aDescription;
+    resetFocusToParentHTML(description);
+    var htmlEditor = iframe.contentWindow.docShell.editor;
+    var e = aIsInDesignMode ? root : editor;
+    e.focus();
+    is(fm.focusedElement, e,
+       description + ": focus() of editor didn't move focus as expected");
+    is(utils.IMEStatus, utils.IME_STATUS_ENABLED,
+       description + ": IME isn't enabled when the editor gets focus");
+    var flags = htmlEditor.flags;
+    htmlEditor.flags |= kReadonly;
+    is(fm.focusedElement, e,
+       description + ": when editor becomes readonly, focus moved unexpectedly");
+    is(utils.IMEStatus, utils.IME_STATUS_DISABLED,
+       description + ": when editor becomes readonly, IME is still enabled");
+    htmlEditor.flags = flags;
+    is(fm.focusedElement, e,
+       description + ": when editor becomes read-write, focus moved unexpectedly");
+    is(utils.IMEStatus, utils.IME_STATUS_ENABLED,
+       description + ": when editor becomes read-write, IME is still disabled");
+  }
+
+  // hide all iframes
+  document.getElementById("iframe_not_editable").style.display = "none";
+  document.getElementById("iframe_html").style.display = "none";
+  document.getElementById("iframe_designMode").style.display = "none";
+  document.getElementById("iframe_body").style.display = "none";
+  document.getElementById("iframe_p").style.display = "none";
+
+  // non editable HTML element and input element can get focus.
+  iframe = document.getElementById("iframe_not_editable");
+  iframe.style.display = "inline";
+  editor = iframe.contentDocument.getElementById("editor");
+  root = iframe.contentDocument.documentElement;
+  resetFocusToInput("initializing for iframe_not_editable");
+
+  testTabKey(true, root, false, prev, true,
+             false, "input#prev[readonly] -> html");
+  testTabKey(true, editor, true, root, false,
+             true, "html -> input in the subdoc");
+  testTabKey(true, next, true, editor, true,
+             false, "input in the subdoc -> input#next[readonly]");
+  testTabKey(false, editor, true, next, true,
+             true, "input#next[readonly] -> input in the subdoc");
+  testTabKey(false, root, false, editor, true,
+             false, "input in the subdoc -> html");
+  testTabKey(false, prev, true, root, false,
+             false, "html -> input#next[readonly]");
+
+  iframe.style.display = "none";
+
+  // HTML element (of course, it's root) must enables IME.
+  iframe = document.getElementById("iframe_html");
+  iframe.style.display = "inline";
+  editor = iframe.contentDocument.getElementById("editor");
+  root = iframe.contentDocument.documentElement;
+  resetFocusToInput("initializing for iframe_html");
+
+  testTabKey(true, editor, true, prev, true,
+             true, "input#prev[readonly] -> html[contentediable=true]");
+  testTabKey(true, next, true, editor, true,
+             false, "html[contentediable=true] -> input#next[readonly]");
+  testTabKey(false, editor, true, next, true,
+             true, "input#next[readonly] -> html[contentediable=true]");
+  testTabKey(false, prev, true, editor, true,
+             false, "html[contenteditable=true] -> input[readonly]");
+
+  prev.style.display = "none";
+  resetFocusToParentHTML("testing iframe_html");
+  testTabKey(true, editor, true, html, false,
+             true, "html of parent -> html[contentediable=true]");
+  testTabKey(false, html, false, editor, true,
+             false, "html[contenteditable=true] -> html of parent");
+  prev.style.display = "inline";
+  resetFocusToInput("after parent html <-> html[contenteditable=true]");
+
+  testMouseClick(editor, true, false, prev, true, true, "iframe_html");
+
+  testOnEditorFlagChange("html[contentediable=true]", false);
+
+  iframe.style.display = "none";
+
+  // designMode should behave like <html contenteditable="true"></html>
+  // but focus/blur events shouldn't be fired on its root element because
+  // any elements shouldn't be focused state in designMode.
+  iframe = document.getElementById("iframe_designMode");
+  iframe.style.display = "inline";
+  iframe.contentDocument.designMode = "on";
+  editor = iframe.contentDocument.getElementById("editor");
+  root = iframe.contentDocument.documentElement;
+  resetFocusToInput("initializing for iframe_designMode");
+
+  testTabKey(true, root, false, prev, true,
+             true, "input#prev[readonly] -> html in designMode");
+  testTabKey(true, next, true, root, false,
+             false, "html in designMode -> input#next[readonly]");
+  testTabKey(false, root, false, next, true,
+             true, "input#next[readonly] -> html in designMode");
+  testTabKey(false, prev, true, root, false,
+             false, "html in designMode -> input#prev[readonly]");
+
+  prev.style.display = "none";
+  resetFocusToParentHTML("testing iframe_designMode");
+  testTabKey(true, root, false, html, false,
+             true, "html of parent -> html in designMode");
+  testTabKey(false, html, false, root, false,
+             false, "html in designMode -> html of parent");
+  prev.style.display = "inline";
+  resetFocusToInput("after parent html <-> html in designMode");
+
+  testMouseClick(editor, false, true, prev, true, true, "iframe_designMode");
+
+  testOnEditorFlagChange("html in designMode", true);
+
+  iframe.style.display = "none";
+
+  // When there is no HTML element but the BODY element is editable,
+  // the body element should get focus and enables IME.
+  iframe = document.getElementById("iframe_body");
+  iframe.style.display = "inline";
+  editor = iframe.contentDocument.getElementById("editor");
+  root = iframe.contentDocument.documentElement;
+  resetFocusToInput("initializing for iframe_body");
+
+  testTabKey(true, editor, true, prev, true,
+             true, "input#prev[readonly] -> body[contentediable=true]");
+  testTabKey(true, next, true, editor, true,
+             false, "body[contentediable=true] -> input#next[readonly]");
+  testTabKey(false, editor, true, next, true,
+             true, "input#next[readonly] -> body[contentediable=true]");
+  testTabKey(false, prev, true, editor, true,
+             false, "body[contenteditable=true] -> input#prev[readonly]");
+
+  prev.style.display = "none";
+  resetFocusToParentHTML("testing iframe_body");
+  testTabKey(true, editor, true, html, false,
+             true, "html of parent -> body[contentediable=true]");
+  testTabKey(false, html, false, editor, true,
+             false, "body[contenteditable=true] -> html of parent");
+  prev.style.display = "inline";
+  resetFocusToInput("after parent html <-> body[contenteditable=true]");
+
+  testMouseClick(editor, true, false, prev, true, true, "iframe_body");
+
+  testOnEditorFlagChange("body[contentediable=true]", false);
+
+  iframe.style.display = "none";
+
+  // When HTML/BODY elements are not editable, focus shouldn't be moved to
+  // the editable content directly.
+  iframe = document.getElementById("iframe_p");
+  iframe.style.display = "inline";
+  editor = iframe.contentDocument.getElementById("editor");
+  root = iframe.contentDocument.documentElement;
+  resetFocusToInput("initializing for iframe_p");
+
+  testTabKey(true, root, false, prev, true,
+             false, "input#prev[readonly] -> html (has p[contenteditable=true])");
+  testTabKey(true, editor, true, root, false,
+             true, "html (has p[contenteditable=true]) -> p[contentediable=true]");
+  testTabKey(true, next, true, editor, true,
+             false, "p[contentediable=true] -> input#next[readonly]");
+  testTabKey(false, editor, true, next, true,
+             true, "input#next[readonly] -> p[contentediable=true]");
+  testTabKey(false, root, false, editor, true,
+             false, "p[contenteditable=true] -> html (has p[contenteditable=true])");
+  testTabKey(false, prev, true, root, false,
+             false, "html (has p[contenteditable=true]) -> input#prev[readonly]");
+  prev.style.display = "none";
+
+  resetFocusToParentHTML("testing iframe_p");
+  testTabKey(true, root, false, html, false,
+             false, "html of parent -> html (has p[contentediable=true])");
+  testTabKey(false, html, false, root, false,
+             false, "html (has p[contentediable=true]) -> html of parent");
+  prev.style.display = "inline";
+  resetFocusToInput("after parent html <-> html (has p[contentediable=true])");
+
+  testMouseClick(root, false, true, prev, true, false, "iframe_p");
+
+  testOnEditorFlagChange("p[contenteditable=true]", false);
+
+  iframe.style.display = "none";
+
+  window.close();
+}
+
+</script>
+</body>
+
+</html>
diff --git a/widget/tests/window_mouse_scroll_win.html b/widget/tests/window_mouse_scroll_win.html
new file mode 100644
index 0000000000..bf90abb1b5
--- /dev/null
+++ b/widget/tests/window_mouse_scroll_win.html
@@ -0,0 +1,1516 @@
+<html lang="en-US"
+      style="font-family: Arial; font-size: 10px; line-height: 16px;">
+<head>
+  <title>Test for mouse scroll handling on Windows</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"></script>
+  <link rel="stylesheet" type="text/css"
+          href="chrome://mochikit/content/tests/SimpleTest/test.css" />
+</head>
+<body onunload="onUnload();">
+<div id="display" style="width: 5000px; height: 5000px;">
+<p id="p1" style="font-size: 16px; width: 100px; height: 100px;">1st &lt;p&gt;.</p>
+<p id="p2" style="font-size: 32px; width: 100px; height: 100px;">2nd &lt;p&gt;.</p>
+</div>
+<script class="testbody" type="application/javascript">
+
+window.arguments[0].SimpleTest.waitForFocus(prepareTests, window);
+
+const nsIDOMWindowUtils = Ci.nsIDOMWindowUtils;
+
+const WHEEL_PAGESCROLL = 4294967295;
+
+const WM_VSCROLL     = 0x0115;
+const WM_HSCROLL     = 0x0114;
+const WM_MOUSEWHEEL  = 0x020A;
+const WM_MOUSEHWHEEL = 0x020E;
+
+const SB_LINEUP    = 0;
+const SB_LINELEFT  = 0;
+const SB_LINEDOWN  = 1;
+const SB_LINERIGHT = 1;
+const SB_PAGEUP    = 2;
+const SB_PAGELEFT  = 2;
+const SB_PAGEDOWN  = 3;
+const SB_PAGERIGHT = 3;
+
+const SHIFT_L = 0x0100;
+const SHIFT_R = 0x0200;
+const CTRL_L  = 0x0400;
+const CTRL_R  = 0x0800;
+const ALT_L   = 0x1000;
+const ALT_R   = 0x2000;
+
+const DOM_PAGE_SCROLL_DELTA = 32768;
+
+const kSystemScrollSpeedOverridePref = "mousewheel.system_scroll_override.enabled";
+
+const kAltKeyActionPref         = "mousewheel.with_alt.action";
+const kCtrlKeyActionPref        = "mousewheel.with_control.action";
+const kShiftKeyActionPref       = "mousewheel.with_shift.action";
+const kWinKeyActionPref         = "mousewheel.with_meta.action";
+
+const kAltKeyDeltaMultiplierXPref   = "mousewheel.with_alt.delta_multiplier_x";
+const kAltKeyDeltaMultiplierYPref   = "mousewheel.with_alt.delta_multiplier_y";
+const kCtrlKeyDeltaMultiplierXPref  = "mousewheel.with_control.delta_multiplier_x";
+const kCtrlKeyDeltaMultiplierYPref  = "mousewheel.with_control.delta_multiplier_y";
+const kShiftKeyDeltaMultiplierXPref = "mousewheel.with_shift.delta_multiplier_x";
+const kShiftKeyDeltaMultiplierYPref = "mousewheel.with_shift.delta_multiplier_y";
+const kWinKeyDeltaMultiplierXPref   = "mousewheel.with_meta.delta_multiplier_x";
+const kWinKeyDeltaMultiplierYPref   = "mousewheel.with_meta.delta_multiplier_y";
+
+const kEmulateWheelByWMSCROLLPref = "mousewheel.emulate_at_wm_scroll";
+const kVAmountPref                = "mousewheel.windows.vertical_amount_override";
+const kHAmountPref                = "mousewheel.windows.horizontal_amount_override";
+const kTimeoutPref                = "mousewheel.windows.transaction.timeout";
+
+const kMouseLineScrollEvent  = "DOMMouseScroll";
+const kMousePixelScrollEvent = "MozMousePixelScroll";
+
+const kVAxis = MouseScrollEvent.VERTICAL_AXIS;
+const kHAxis = MouseScrollEvent.HORIZONTAL_AXIS;
+
+var gLineHeight = 0;
+var gCharWidth  = 0;
+var gPageHeight = 0;
+var gPageWidth  = 0;
+
+var gP1 = document.getElementById("p1");
+var gP2 = document.getElementById("p2");
+
+var gOtherWindow;
+
+function ok(aCondition, aMessage) {
+  window.arguments[0].SimpleTest.ok(aCondition, aMessage);
+}
+
+function is(aLeft, aRight, aMessage) {
+  window.arguments[0].SimpleTest.is(aLeft, aRight, aMessage);
+}
+
+function isnot(aLeft, aRight, aMessage) {
+  window.arguments[0].SimpleTest.isnot(aLeft, aRight, aMessage);
+}
+
+function todo_is(aLeft, aRight, aMessage) {
+  window.arguments[0].SimpleTest.todo_is(aLeft, aRight, aMessage);
+}
+
+function onUnload() {
+  SpecialPowers.clearUserPref(kAltKeyActionPref);
+  SpecialPowers.clearUserPref(kCtrlKeyActionPref);
+  SpecialPowers.clearUserPref(kShiftKeyActionPref);
+  SpecialPowers.clearUserPref(kWinKeyActionPref);
+
+  SpecialPowers.clearUserPref(kAltKeyDeltaMultiplierXPref);
+  SpecialPowers.clearUserPref(kAltKeyDeltaMultiplierYPref);
+  SpecialPowers.clearUserPref(kCtrlKeyDeltaMultiplierXPref);
+  SpecialPowers.clearUserPref(kCtrlKeyDeltaMultiplierYPref);
+  SpecialPowers.clearUserPref(kShiftKeyDeltaMultiplierXPref);
+  SpecialPowers.clearUserPref(kShiftKeyDeltaMultiplierYPref);
+  SpecialPowers.clearUserPref(kWinKeyDeltaMultiplierXPref);
+  SpecialPowers.clearUserPref(kWinKeyDeltaMultiplierYPref);
+
+  SpecialPowers.clearUserPref(kSystemScrollSpeedOverridePref);
+  SpecialPowers.clearUserPref(kEmulateWheelByWMSCROLLPref);
+  SpecialPowers.clearUserPref(kVAmountPref);
+  SpecialPowers.clearUserPref(kHAmountPref);
+  SpecialPowers.clearUserPref(kTimeoutPref);
+  window.arguments[0].SimpleTest.finish();
+}
+
+function getWindowUtils(aWindow) {
+  if (!aWindow) {
+    aWindow = window;
+  }
+  return aWindow.windowUtils;
+}
+
+function getPointInScreen(aElement, aWindow) {
+  if (!aWindow) {
+    aWindow = window;
+  }
+  var bounds = aElement.getBoundingClientRect();
+  return { x: bounds.left + aWindow.mozInnerScreenX,
+           y: bounds.top + aWindow.mozInnerScreenY };
+}
+
+function cut(aNum) {
+  return (aNum >= 0) ? Math.floor(aNum) : Math.ceil(aNum);
+}
+
+/**
+ * Make each steps for the tests in following arrays in global scope. Each item
+ * of the arrays will be executed after previous test is finished.
+ *
+ * description:
+ *   Set the description of the test.  This will be used for the message of is()
+ *   or the others.
+ *
+ * message:
+ *   aNativeMessage of nsIDOMWindowUtils.sendNativeMouseScrollEvent().
+ *   Must be WM_MOUSEWHEEL, WM_MOUSEHWHEEL, WM_VSCROLL or WM_HSCROLL.
+ *
+ * delta:
+ *   The native delta value for WM_MOUSEWHEEL or WM_MOUSEHWHEEL.
+ *   Or one of the SB_* const value for WM_VSCROLL or WM_HSCROLL.
+ *
+ * target:
+ *   The target element, under the mouse cursor.
+ *
+ * window:
+ *   The window which is used for getting nsIDOMWindowUtils.
+ *
+ * modifiers:
+ *   Pressed modifier keys, 0 means no modifier key is pressed.
+ *   Otherwise, one or more values of SHIFT_L, SHIFT_R, CTRL_L, CTRL_R,
+ *   ALT_L or ALT_R.
+ *
+ * additionalFlags:
+ *   aAdditionalFlags of nsIDOMWindowUtils.sendNativeMouseScrollEvent().
+ *   See the document of nsIDOMWindowUtils for the detail of the values.
+ *
+ * onLineScrollEvent:
+ *   Must be a function or null.
+ *   If the value is a function, it will be called when DOMMouseScroll event
+ *   is received by the synthesized event.
+ *   If return true, the common checks are canceled.
+ *
+ * onPixelScrollEvent:
+ *   Must be a function or null.
+ *   If the value is a function, it will be called when MozMousePixelScroll
+ *   event is received by the synthesized event.
+ *   If return true, the common checks are canceled.
+ *
+ * expected:
+ *   Must not be null and this must have:
+ *     axis:
+ *       kVAxis if the synthesized event causes vertical scroll. Otherwise,
+ *       it causes horizontal scroll, kHAxis.
+ *     lines:
+ *       Integer value which is expected detail attribute value of
+ *       DOMMouseScroll.  If the event shouldn't be fired, must be 0.
+ *     pixels:
+ *       Integer value or a function which returns double value.  The value is
+ *       expected detail attribute value of MozMousePixelScroll.
+ *       If the event shouldn't be fired, must be 0.
+ *
+ *   Note that if both lines and pixels are 0, the test framework waits
+ *   a few seconds. After that, go to next test.
+ *
+ * init:
+ *   Must be a function or null.  If this value is a function, it's called
+ *   before synthesizing the native event.
+ *
+ * finish:
+ *   Must be a function or null.  If this value is a function, it's called
+ *   after received all expected events or timeout if no events are expected.
+ */
+
+// First, get the computed line height, char width, page height and page width.
+var gPreparingSteps = [
+  { description: "Preparing gLineHeight",
+    message: WM_MOUSEWHEEL, delta: -120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    onLineScrollEvent(aEvent) {
+      return true;
+    },
+    onPixelScrollEvent(aEvent) {
+      gLineHeight = aEvent.detail;
+      return true;
+    },
+    expected: {
+      axis: kVAxis, lines: 1, pixels: 1,
+    },
+    init() {
+      SpecialPowers.setIntPref(kVAmountPref, 1);
+      SpecialPowers.setIntPref(kHAmountPref, 1);
+    },
+  },
+  { description: "Preparing gCharWidth",
+    message: WM_MOUSEHWHEEL, delta: 120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    onLineScrollEvent(aEvent) {
+      return true;
+    },
+    onPixelScrollEvent(aEvent) {
+      gCharWidth = aEvent.detail;
+      return true;
+    },
+    expected: {
+      axis: kVAxis, lines: 1, pixels: 1,
+    },
+  },
+  { description: "Preparing gPageHeight",
+    message: WM_MOUSEWHEEL, delta: -120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    onLineScrollEvent(aEvent) {
+      return true;
+    },
+    onPixelScrollEvent(aEvent) {
+      gPageHeight = aEvent.detail;
+      return true;
+    },
+    expected: {
+      axis: kHAxis, lines: 1, pixels: 1,
+    },
+    init() {
+      SpecialPowers.setIntPref(kVAmountPref, 0xFFFF);
+      SpecialPowers.setIntPref(kHAmountPref, 0xFFFF);
+    },
+  },
+  { description: "Preparing gPageWidth",
+    message: WM_MOUSEHWHEEL, delta: 120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    onLineScrollEvent(aEvent) {
+      return true;
+    },
+    onPixelScrollEvent(aEvent) {
+      gPageWidth = aEvent.detail;
+      return true;
+    },
+    expected: {
+      axis: kHAxis, lines: 1, pixels: 1,
+    },
+    finish() {
+      ok(gLineHeight > 0, "gLineHeight isn't positive got " + gLineHeight);
+      ok(gCharWidth > 0, "gCharWidth isn't positive got " + gCharWidth);
+      ok(gPageHeight > 0, "gPageHeight isn't positive got " + gPageHeight);
+      ok(gPageWidth > 0, "gPageWidth isn't positive got " + gPageWidth);
+
+      ok(gPageHeight > gLineHeight,
+         "gPageHeight must be larger than gLineHeight");
+      ok(gPageWidth > gCharWidth,
+         "gPageWidth must be larger than gCharWidth");
+      runNextTest(gBasicTests, 0);
+    },
+  },
+];
+
+var gBasicTests = [
+  // Widget shouldn't dispatch a pixel event if the delta can be devided by
+  // lines to be scrolled.  However, pixel events should be fired by ESM.
+  { description: "WM_MOUSEWHEEL, -120, 3 lines",
+    message: WM_MOUSEWHEEL, delta: -120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 3, pixels() { return gLineHeight * 3; },
+    },
+    init() {
+      SpecialPowers.setIntPref(kVAmountPref, 3);
+      SpecialPowers.setIntPref(kHAmountPref, 3);
+    },
+  },
+
+  { description: "WM_MOUSEWHEEL, 120, -3 lines",
+    message: WM_MOUSEWHEEL, delta: 120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: -3, pixels() { return gLineHeight * -3; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, 120, 3 chars",
+    message: WM_MOUSEHWHEEL, delta: 120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 3, pixels() { return gCharWidth * 3; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, -120, -3 chars",
+    message: WM_MOUSEHWHEEL, delta: -120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: -3, pixels() { return gCharWidth * -3; },
+    },
+  },
+
+  // Pixel scroll event should be fired always but line scroll event should be
+  // fired only when accumulated delta value is over a line.
+  { description: "WM_MOUSEWHEEL, -20, 0.5 lines",
+    message: WM_MOUSEWHEEL, delta: -20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 0, pixels() { return gLineHeight / 2; },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, -20, 0.5 lines (pending: 0.5 lines)",
+    message: WM_MOUSEWHEEL, delta: -20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight / 2; },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, -20, 0.5 lines",
+    message: WM_MOUSEWHEEL, delta: -20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 0, pixels() { return gLineHeight / 2; },
+    },
+  },
+
+  { description: "WM_MOUSEWHEEL, 20, -0.5 lines (pending: 0.5 lines)",
+    message: WM_MOUSEWHEEL, delta: 20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 0, pixels() { return gLineHeight / -2; },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, 20, -0.5 lines (pending: -0.5 lines)",
+    message: WM_MOUSEWHEEL, delta: 20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: -1, pixels() { return -gLineHeight / 2; },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, 20, -0.5 lines",
+    message: WM_MOUSEWHEEL, delta: 20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 0, pixels() { return gLineHeight / -2; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, 20, 0.5 chars",
+    message: WM_MOUSEHWHEEL, delta: 20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 0, pixels() { return gCharWidth / 2; },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, 20, 0.5 chars (pending: 0.5 chars)",
+    message: WM_MOUSEHWHEEL, delta: 20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth / 2; },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, 20, 0.5 chars",
+    message: WM_MOUSEHWHEEL, delta: 20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 0, pixels() { return gCharWidth / 2; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, -20, -0.5 chars (pending: 0.5 chars)",
+    message: WM_MOUSEHWHEEL, delta: -20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 0, pixels() { return gCharWidth / -2; },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, -20, -0.5 chars (pending: -0.5 chars)",
+    message: WM_MOUSEHWHEEL, delta: -20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: -1, pixels() { return -gCharWidth / 2; },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, -20, -0.5 chars",
+    message: WM_MOUSEHWHEEL, delta: -20,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 0, pixels() { return gCharWidth / -2; },
+    },
+  },
+
+  // Even if the mouse cursor is an element whose font-size is different than
+  // the scrollable element, the pixel scroll amount shouldn't be changed.
+  // Widget shouldn't dispatch a pixel event if the delta can be devided by
+  // lines to be scrolled.  However, pixel events should be fired by ESM.
+  { description: "WM_MOUSEWHEEL, -120, 3 lines, on the other div whose font-size is larger",
+    message: WM_MOUSEWHEEL, delta: -120,
+    target: gP2, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 3, pixels() { return gLineHeight * 3; },
+    },
+  },
+
+  { description: "WM_MOUSEWHEEL, 120, -3 lines, on the other div whose font-size is larger",
+    message: WM_MOUSEWHEEL, delta: 120,
+    target: gP2, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: -3, pixels() { return gLineHeight * -3; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, 120, 3 chars, on the other div whose font-size is larger",
+    message: WM_MOUSEHWHEEL, delta: 120,
+    target: gP2, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 3, pixels() { return gCharWidth * 3; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, -120, -3 chars, on the other div whose font-size is larger",
+    message: WM_MOUSEHWHEEL, delta: -120,
+    target: gP2, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: -3, pixels() { return gCharWidth * -3; },
+    },
+  },
+
+  // Modifier key tests
+  { description: "WM_MOUSEWHEEL, -40, 1 line with left Shift",
+    message: WM_MOUSEWHEEL, delta: -40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: SHIFT_L,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, -40, 1 line with right Shift",
+    message: WM_MOUSEWHEEL, delta: -40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: SHIFT_R,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, -40, 1 line with left Ctrl",
+    message: WM_MOUSEWHEEL, delta: -40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: CTRL_L,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, -40, 1 line with right Ctrl",
+    message: WM_MOUSEWHEEL, delta: -40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: CTRL_R,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, -40, 1 line with left Alt",
+    message: WM_MOUSEWHEEL, delta: -40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: ALT_L,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, -40, 1 line with right Alt",
+    message: WM_MOUSEWHEEL, delta: -40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: ALT_R,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, 40, 1 character with left Shift",
+    message: WM_MOUSEHWHEEL, delta: 40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: SHIFT_L,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, 40, 1 character with right Shift",
+    message: WM_MOUSEHWHEEL, delta: 40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: SHIFT_R,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, 40, 1 character with left Ctrl",
+    message: WM_MOUSEHWHEEL, delta: 40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: CTRL_L,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, 40, 1 character with right Ctrl",
+    message: WM_MOUSEHWHEEL, delta: 40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: CTRL_R,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, 40, 1 character with left Alt",
+    message: WM_MOUSEHWHEEL, delta: 40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: ALT_L,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, 40, 1 character with right Alt",
+    message: WM_MOUSEHWHEEL, delta: 40,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: ALT_R,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+
+    finish() {
+      runNextTest(gScrollMessageTests, 0);
+    },
+  },
+];
+
+var gPageScrllTests = [
+  // Pixel scroll event should be fired always but line scroll event should be
+  // fired only when accumulated delta value is over a line.
+  { description: "WM_MOUSEWHEEL, -60, 0.5 pages",
+    message: WM_MOUSEWHEEL, delta: -60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 0, pixels() { return gPageHeight / 2; },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, -60, 0.5 pages (pending: 0.5 pages)",
+    message: WM_MOUSEWHEEL, delta: -60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: DOM_PAGE_SCROLL_DELTA,
+      pixels() { return ((gPageHeight / 2) + (gPageHeight % 2)); },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, -60, 0.5 pages",
+    message: WM_MOUSEWHEEL, delta: -60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 0, pixels() { return gPageHeight / 2; },
+    },
+  },
+
+  { description: "WM_MOUSEWHEEL, 60, -0.5 pages (pending: 0.5 pages)",
+    message: WM_MOUSEWHEEL, delta: 60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 0, pixels() { return gPageHeight / -2; },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, 60, -0.5 pages (pending: -0.5 pages)",
+    message: WM_MOUSEWHEEL, delta: 60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: -DOM_PAGE_SCROLL_DELTA,
+      pixels() { return -((gPageHeight / 2) + (gPageHeight % 2)); },
+    },
+  },
+  { description: "WM_MOUSEWHEEL, 60, -0.5 pages",
+    message: WM_MOUSEWHEEL, delta: 60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 0, pixels() { return gPageHeight / -2; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, 60, 0.5 pages",
+    message: WM_MOUSEHWHEEL, delta: 60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 0, pixels() { return gPageWidth / 2; },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, 60, 0.5 pages (pending: 0.5 pages)",
+    message: WM_MOUSEHWHEEL, delta: 60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: DOM_PAGE_SCROLL_DELTA,
+      pixels() { return ((gPageWidth / 2) + (gPageWidth % 2)); },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, 60, 0.5 pages",
+    message: WM_MOUSEHWHEEL, delta: 60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 0, pixels() { return gPageWidth / 2; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, -60, -0.5 pages (pending: 0.5 pages)",
+    message: WM_MOUSEHWHEEL, delta: -60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 0, pixels() { return gCharWidth / -2; },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, -60, -0.5 pages (pending: -0.5 pages)",
+    message: WM_MOUSEHWHEEL, delta: -60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: -DOM_PAGE_SCROLL_DELTA,
+      pixels() { return -((gCharWidth / 2) + (gCharWidth % 2)); },
+    },
+  },
+  { description: "WM_MOUSEHWHEEL, -60, -0.5 pages",
+    message: WM_MOUSEHWHEEL, delta: -60,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 0, pixels() { return gCharWidth / -2; },
+    },
+  },
+];
+
+var gScrollMessageTests = [
+  // Widget should dispatch neither line scroll event nor pixel scroll event if
+  // the WM_*SCROLL's lParam is NULL and mouse wheel emulation is disabled.
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is NULL, emulation disabled",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 0, pixels: 0,
+    },
+    init() {
+      SpecialPowers.setIntPref(kVAmountPref, 3);
+      SpecialPowers.setIntPref(kHAmountPref, 3);
+      SpecialPowers.setBoolPref(kEmulateWheelByWMSCROLLPref, false);
+    },
+  },
+
+  { description: "WM_VSCROLL, SB_LINEUP, lParam is NULL, emulation disabled",
+    message: WM_VSCROLL, delta: SB_LINEUP,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 0, pixels: 0,
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is NULL, emulation disabled",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 0, pixels: 0,
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINELEFT, lParam is NULL, emulation disabled",
+    message: WM_HSCROLL, delta: SB_LINELEFT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 0, pixels: 0,
+    },
+  },
+
+  // Widget should emulate mouse wheel behavior for WM_*SCROLL even if the
+  // kEmulateWheelByWMSCROLLPref is disabled but the message's lParam is not
+  // NULL. Then, widget doesn't dispatch a pixel event for WM_*SCROLL messages,
+  // but ESM dispatches it instead.
+  { description: "WM_VSCROLL, SB_LINEUP, lParam is not NULL, emulation disabled",
+    message: WM_VSCROLL, delta: SB_LINEUP,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: -1, pixels() { return -gLineHeight; },
+    },
+    init() {
+      SpecialPowers.setBoolPref(kEmulateWheelByWMSCROLLPref, false);
+    },
+  },
+
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is not NULL, emulation disabled",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINELEFT, lParam is not NULL, emulation disabled",
+    message: WM_HSCROLL, delta: SB_LINELEFT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: -1, pixels() { return -gCharWidth; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is not NULL, emulation disabled",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+
+  { description: "WM_VSCROLL, SB_PAGEUP, lParam is not NULL, emulation disabled",
+    message: WM_VSCROLL, delta: SB_PAGEUP,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: -DOM_PAGE_SCROLL_DELTA,
+      pixels() { return -gPageHeight; },
+    },
+  },
+
+  { description: "WM_VSCROLL, SB_PAGEDOWN, lParam is not NULL, emulation disabled",
+    message: WM_VSCROLL, delta: SB_PAGEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: DOM_PAGE_SCROLL_DELTA,
+      pixels() { return gPageHeight; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_PAGELEFT, lParam is not NULL, emulation disabled",
+    message: WM_HSCROLL, delta: SB_PAGELEFT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: -DOM_PAGE_SCROLL_DELTA,
+      pixels() { return -gPageWidth; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_PAGERIGHT, lParam is not NULL, emulation disabled",
+    message: WM_HSCROLL, delta: SB_PAGERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: DOM_PAGE_SCROLL_DELTA,
+      pixels() { return gPageWidth; },
+    },
+  },
+
+  // Widget should emulate mouse wheel behavior for WM_*SCROLL when the
+  // kEmulateWheelByWMSCROLLPref is enabled even if the message's lParam is
+  // NULL. Then, widget doesn't dispatch a pixel event for WM_*SCROLL messages,
+  // but ESM dispatches it instead.
+  { description: "WM_VSCROLL, SB_LINEUP, lParam is NULL, emulation enabled",
+    message: WM_VSCROLL, delta: SB_LINEUP,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: -1, pixels() { return -gLineHeight; },
+    },
+    init() {
+      SpecialPowers.setBoolPref(kEmulateWheelByWMSCROLLPref, true);
+    },
+  },
+
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is NULL, emulation enabled",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINELEFT, lParam is NULL, emulation enabled",
+    message: WM_HSCROLL, delta: SB_LINELEFT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: -1, pixels() { return -gCharWidth; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is NULL, emulation enabled",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+
+  { description: "WM_VSCROLL, SB_PAGEUP, lParam is NULL, emulation enabled",
+    message: WM_VSCROLL, delta: SB_PAGEUP,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: -DOM_PAGE_SCROLL_DELTA,
+      pixels() { return -gPageHeight; },
+    },
+  },
+
+  { description: "WM_VSCROLL, SB_PAGEDOWN, lParam is NULL, emulation enabled",
+    message: WM_VSCROLL, delta: SB_PAGEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: DOM_PAGE_SCROLL_DELTA,
+      pixels() { return gPageHeight; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_PAGELEFT, lParam is NULL, emulation enabled",
+    message: WM_HSCROLL, delta: SB_PAGELEFT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: -DOM_PAGE_SCROLL_DELTA,
+      pixels() { return -gPageWidth; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_PAGERIGHT, lParam is NULL, emulation enabled",
+    message: WM_HSCROLL, delta: SB_PAGERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: DOM_PAGE_SCROLL_DELTA,
+      pixels() { return gPageWidth; },
+    },
+  },
+
+  // Modifier key tests for WM_*SCROLL
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is not NULL, emulation disabled, with left Shift",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: SHIFT_L,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+    init() {
+      SpecialPowers.setBoolPref(kEmulateWheelByWMSCROLLPref, false);
+    },
+  },
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is not NULL, emulation disabled, with right Shift",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: SHIFT_R,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is not NULL, emulation disabled, with left Ctrl",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: CTRL_L,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is not NULL, emulation disabled, with right Ctrl",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: CTRL_L,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is not NULL, emulation disabled, with left Alt",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: ALT_L,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is not NULL, emulation disabled, with right Alt",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: ALT_R,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is not NULL, emulation disabled, with left Shift",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: SHIFT_L,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is not NULL, emulation disabled, with right Shift",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: SHIFT_R,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is not NULL, emulation disabled, with left Ctrl",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: CTRL_L,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is not NULL, emulation disabled, with right Ctrl",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: CTRL_L,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is not NULL, emulation disabled, with left Alt",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: ALT_L,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is not NULL, emulation disabled, with right Alt",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: ALT_R,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+
+    finish() {
+      runDeactiveWindowTests();
+    },
+  },
+];
+
+var gDeactiveWindowTests = [
+  // Typically, mouse drivers send wheel messages to focused window.
+  // However, we prefer to scroll a scrollable element under the mouse cursor.
+  { description: "WM_MOUSEWHEEL, -120, 3 lines, window is deactive",
+    message: WM_MOUSEWHEEL, delta: -120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 3, pixels() { return gLineHeight * 3; },
+    },
+    init() {
+      SpecialPowers.setIntPref(kVAmountPref, 3);
+      SpecialPowers.setIntPref(kHAmountPref, 3);
+    },
+    onLineScrollEvent(aEvent) {
+      var fm = Services.focus;
+      is(fm.activeWindow, gOtherWindow, "The other window isn't activated");
+    },
+  },
+
+  { description: "WM_MOUSEWHEEL, 120, -3 lines, window is deactive",
+    message: WM_MOUSEWHEEL, delta: 120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: -3, pixels() { return gLineHeight * -3; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, 120, 3 chars, window is deactive",
+    message: WM_MOUSEHWHEEL, delta: 120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 3, pixels() { return gCharWidth * 3; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, -120, -3 chars, window is deactive",
+    message: WM_MOUSEHWHEEL, delta: -120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: -3, pixels() { return gCharWidth * -3; },
+    },
+  },
+
+  // Of course, even if some drivers prefer the cursor position, we don't need
+  // to change anything.
+  { description: "WM_MOUSEWHEEL, -120, 3 lines, window is deactive (receive the message directly)",
+    message: WM_MOUSEWHEEL, delta: -120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kVAxis, lines: 3, pixels() { return gLineHeight * 3; },
+    },
+  },
+
+  { description: "WM_MOUSEWHEEL, 120, -3 lines, window is deactive (receive the message directly)",
+    message: WM_MOUSEWHEEL, delta: 120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kVAxis, lines: -3, pixels() { return gLineHeight * -3; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, 120, 3 chars, window is deactive (receive the message directly)",
+    message: WM_MOUSEHWHEEL, delta: 120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kHAxis, lines: 3, pixels() { return gCharWidth * 3; },
+    },
+  },
+
+  { description: "WM_MOUSEHWHEEL, -120, -3 chars, window is deactive (receive the message directly)",
+    message: WM_MOUSEHWHEEL, delta: -120,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kHAxis, lines: -3, pixels() { return gCharWidth * -3; },
+    },
+  },
+
+  // Same for WM_*SCROLL if lParam is not NULL
+  { description: "WM_VSCROLL, SB_LINEUP, lParam is not NULL, emulation disabled, window is deactive",
+    message: WM_VSCROLL, delta: SB_LINEUP,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: -1, pixels() { return -gLineHeight; },
+    },
+    init() {
+      SpecialPowers.setBoolPref(kEmulateWheelByWMSCROLLPref, false);
+    },
+  },
+
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is not NULL, emulation disabled, window is deactive",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINELEFT, lParam is not NULL, emulation disabled, window is deactive",
+    message: WM_HSCROLL, delta: SB_LINELEFT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: -1, pixels() { return -gCharWidth; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is not NULL, emulation disabled, window is deactive",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+
+  // Same for WM_*SCROLL if lParam is NULL but emulation is enabled
+  { description: "WM_VSCROLL, SB_LINEUP, lParam is NULL, emulation enabled, window is deactive",
+    message: WM_VSCROLL, delta: SB_LINEUP,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: -1, pixels() { return -gLineHeight; },
+    },
+    init() {
+      SpecialPowers.setBoolPref(kEmulateWheelByWMSCROLLPref, true);
+    },
+  },
+
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is NULL, emulation enabled, window is deactive",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINELEFT, lParam is NULL, emulation enabled, window is deactive",
+    message: WM_HSCROLL, delta: SB_LINELEFT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: -1, pixels() { return -gCharWidth; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is NULL, emulation enabled, window is deactive",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: 0,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+
+  // Same for WM_*SCROLL if lParam is not NULL and message sent to the deactive window directly
+  { description: "WM_VSCROLL, SB_LINEUP, lParam is not NULL, emulation disabled, window is deactive (receive the message directly)",
+    message: WM_VSCROLL, delta: SB_LINEUP,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL |
+                     nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kVAxis, lines: -1, pixels() { return -gLineHeight; },
+    },
+    init() {
+      SpecialPowers.setBoolPref(kEmulateWheelByWMSCROLLPref, false);
+    },
+  },
+
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is not NULL, emulation disabled, window is deactive (receive the message directly)",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL |
+                     nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINELEFT, lParam is not NULL, emulation disabled, window is deactive (receive the message directly)",
+    message: WM_HSCROLL, delta: SB_LINELEFT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL |
+                     nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kHAxis, lines: -1, pixels() { return -gCharWidth; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is not NULL, emulation disabled, window is deactive (receive the message directly)",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL |
+                     nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+  },
+
+  // Same for WM_*SCROLL if lParam is NULL but emulation is enabled, and message sent to the deactive window directly
+  { description: "WM_VSCROLL, SB_LINEUP, lParam is NULL, emulation enabled, window is deactive (receive the message directly)",
+    message: WM_VSCROLL, delta: SB_LINEUP,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kVAxis, lines: -1, pixels() { return -gLineHeight; },
+    },
+    init() {
+      SpecialPowers.setBoolPref(kEmulateWheelByWMSCROLLPref, true);
+    },
+  },
+
+  { description: "WM_VSCROLL, SB_LINEDOWN, lParam is NULL, emulation enabled, window is deactive (receive the message directly)",
+    message: WM_VSCROLL, delta: SB_LINEDOWN,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kVAxis, lines: 1, pixels() { return gLineHeight; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINELEFT, lParam is NULL, emulation enabled, window is deactive (receive the message directly)",
+    message: WM_HSCROLL, delta: SB_LINELEFT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kHAxis, lines: -1, pixels() { return -gCharWidth; },
+    },
+  },
+
+  { description: "WM_HSCROLL, SB_LINERIGHT, lParam is NULL, emulation enabled, window is deactive (receive the message directly)",
+    message: WM_HSCROLL, delta: SB_LINERIGHT,
+    target: gP1, x: 10, y: 10, window,
+    modifiers: 0,
+    additionalFlags: nsIDOMWindowUtils.MOUSESCROLL_PREFER_WIDGET_AT_POINT,
+    expected: {
+      axis: kHAxis, lines: 1, pixels() { return gCharWidth; },
+    },
+
+    finish() {
+      gOtherWindow.close();
+      gOtherWindow = null;
+      window.close();
+    },
+  },
+];
+
+function runDeactiveWindowTests() {
+  gOtherWindow = window.open("window_mouse_scroll_win_2.html", "_blank",
+                             "chrome,width=100,height=100,top=700,left=700");
+
+  window.arguments[0].SimpleTest.waitForFocus(function() {
+    runNextTest(gDeactiveWindowTests, 0);
+  }, gOtherWindow);
+}
+
+function runNextTest(aTests, aIndex) {
+  if (aIndex > 0 && aTests[aIndex - 1] && aTests[aIndex - 1].finish) {
+    aTests[aIndex - 1].finish();
+  }
+
+  if (aTests.length == aIndex) {
+    return;
+  }
+
+  var test = aTests[aIndex++];
+  if (test.init) {
+    test.init();
+  }
+  test.handled = { lines: false, pixels: false };
+
+  switch (test.message) {
+    case WM_MOUSEWHEEL:
+    case WM_MOUSEHWHEEL:
+    case WM_VSCROLL:
+    case WM_HSCROLL:
+      var expectedLines = test.expected.lines;
+      var expectedPixels =
+        cut((typeof test.expected.pixels == "function") ?
+               test.expected.pixels() : test.expected.pixels);
+      var handler = function(aEvent) {
+        var doCommonTests = true;
+
+        if (!aEvent) {
+          ok(!test.handled.lines,
+             test.description + ", line scroll event has been handled");
+          ok(!test.handled.pixels,
+             test.description + ", pixel scroll event has been handled");
+          doCommonTests = false;
+        } else if (aEvent.type == kMouseLineScrollEvent) {
+          ok(!test.handled.lines,
+             test.description + ":(" + aEvent.type + "), same event has already been handled");
+          test.handled.lines = true;
+          isnot(expectedLines, 0,
+                test.description + ":(" + aEvent.type + "), event shouldn't be fired");
+          if (test.onLineScrollEvent && test.onLineScrollEvent(aEvent)) {
+            doCommonTests = false;
+          }
+        } else if (aEvent.type == kMousePixelScrollEvent) {
+          ok(!test.handled.pixels,
+             test.description + ":(" + aEvent.type + "), same event has already been handled");
+          test.handled.pixels = true;
+          isnot(expectedPixels, 0,
+                test.description + ":(" + aEvent.type + "), event shouldn't be fired");
+          if (test.onPixelScrollEvent && test.onPixelScrollEvent(aEvent)) {
+            doCommonTests = false;
+          }
+        }
+
+        if (doCommonTests) {
+          var expectedDelta =
+            (aEvent.type == kMouseLineScrollEvent) ?
+              expectedLines : expectedPixels;
+          is(aEvent.target.id, test.target.id,
+             test.description + ":(" + aEvent.type + "), ID mismatch");
+          is(aEvent.axis, test.expected.axis,
+             test.description + ":(" + aEvent.type + "), axis mismatch");
+          ok(aEvent.detail != 0,
+             test.description + ":(" + aEvent.type + "), delta must not be 0");
+          is(aEvent.detail, expectedDelta,
+             test.description + ":(" + aEvent.type + "), delta mismatch");
+          is(aEvent.shiftKey, (test.modifiers & (SHIFT_L | SHIFT_R)) != 0,
+             test.description + ":(" + aEvent.type + "), shiftKey mismatch");
+          is(aEvent.ctrlKey, (test.modifiers & (CTRL_L | CTRL_R)) != 0,
+             test.description + ":(" + aEvent.type + "), ctrlKey mismatch");
+          is(aEvent.altKey, (test.modifiers & (ALT_L | ALT_R)) != 0,
+             test.description + ":(" + aEvent.type + "), altKey mismatch");
+        }
+
+        if (!aEvent || (test.handled.lines || expectedLines == 0) &&
+                       (test.handled.pixels || expectedPixels == 0)) {
+          // Don't scroll actually.
+          if (aEvent) {
+            aEvent.preventDefault();
+          }
+          test.target.removeEventListener(kMouseLineScrollEvent, handler, true);
+          test.target.removeEventListener(kMousePixelScrollEvent, handler, true);
+          setTimeout(runNextTest, 0, aTests, aIndex);
+        }
+      };
+
+      test.target.addEventListener(kMouseLineScrollEvent, handler, true);
+      test.target.addEventListener(kMousePixelScrollEvent, handler, true);
+
+      if (expectedLines == 0 && expectedPixels == 0) {
+        // The timeout might not be enough if system is slow by other process,
+        // so, the test might be passed unexpectedly.  However, it must be able
+        // to be detected by random orange.
+        setTimeout(handler, 500);
+      }
+
+      var utils = getWindowUtils(test.window);
+      var ptInScreen = getPointInScreen(test.target, test.window);
+      var isVertical =
+        ((test.message == WM_MOUSEWHEEL) || (test.message == WM_VSCROLL));
+      var deltaX = !isVertical ? test.delta : 0;
+      var deltaY = isVertical ? test.delta : 0;
+      utils.sendNativeMouseScrollEvent(ptInScreen.x + test.x,
+                                       ptInScreen.y + test.y,
+                                       test.message, deltaX, deltaY, 0,
+                                       test.modifiers,
+                                       test.additionalFlags,
+                                       test.target);
+      break;
+    default:
+      ok(false, test.description + ": invalid message");
+      // Let's timeout.
+  }
+}
+
+function prepareTests() {
+  // Disable special action with modifier key
+  SpecialPowers.setIntPref(kAltKeyActionPref, 1);
+  SpecialPowers.setIntPref(kCtrlKeyActionPref, 1);
+  SpecialPowers.setIntPref(kShiftKeyActionPref, 1);
+  SpecialPowers.setIntPref(kWinKeyActionPref, 1);
+
+  SpecialPowers.setIntPref(kAltKeyDeltaMultiplierXPref, 100);
+  SpecialPowers.setIntPref(kAltKeyDeltaMultiplierYPref, 100);
+  SpecialPowers.setIntPref(kCtrlKeyDeltaMultiplierXPref, 100);
+  SpecialPowers.setIntPref(kCtrlKeyDeltaMultiplierYPref, 100);
+  SpecialPowers.setIntPref(kShiftKeyDeltaMultiplierXPref, 100);
+  SpecialPowers.setIntPref(kShiftKeyDeltaMultiplierYPref, 100);
+  SpecialPowers.setIntPref(kWinKeyDeltaMultiplierXPref, 100);
+  SpecialPowers.setIntPref(kWinKeyDeltaMultiplierYPref, 100);
+
+  SpecialPowers.setBoolPref(kSystemScrollSpeedOverridePref, false);
+  SpecialPowers.setIntPref(kTimeoutPref, -1);
+
+  runNextTest(gPreparingSteps, 0);
+}
+
+</script>
+</body>
+
+</html>
diff --git a/widget/tests/window_mouse_scroll_win_2.html b/widget/tests/window_mouse_scroll_win_2.html
new file mode 100644
index 0000000000..c8d3762405
--- /dev/null
+++ b/widget/tests/window_mouse_scroll_win_2.html
@@ -0,0 +1,6 @@
+<!DOCTYPE HTML>
+<html>
+<body>
+  Helper file for window_mouse_scroll_win.html
+</body>
+</html>
diff --git a/widget/tests/window_picker_no_crash_child.html b/widget/tests/window_picker_no_crash_child.html
new file mode 100644
index 0000000000..c980f979be
--- /dev/null
+++ b/widget/tests/window_picker_no_crash_child.html
@@ -0,0 +1,6 @@
+<!doctype html>
+<title>Picker window</title>
+<form name="form1">
+  <input type="file" name="uploadbox" id="uploadbox" onclick="window.clicked = true;">
+  <input type="file" name="multiple" id="multiple" multiple onclick="window.clicked = true">
+</form>
diff --git a/widget/tests/window_state_windows.xhtml b/widget/tests/window_state_windows.xhtml
new file mode 100644
index 0000000000..60989db144
--- /dev/null
+++ b/widget/tests/window_state_windows.xhtml
@@ -0,0 +1,80 @@
+<?xml version="1.0"?>
+
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<?xml-stylesheet href="chrome://mochikit/content/tests/SimpleTest/test.css" type="text/css"?>
+
+<window id="NativeWindow"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        width="300"
+        height="300"
+        onload="onLoad();"
+        title="Window State Tests">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+  <script type="application/javascript">
+    <![CDATA[
+
+    SimpleTest.waitForExplicitFinish();
+
+    function onLoad() {
+      var win = Services.wm.getMostRecentWindow("navigator:browser");
+
+      /*
+      switch(win.windowState) {
+        case win.STATE_FULLSCREEN:
+        dump("STATE_FULLSCREEN \n");
+        break;
+        case win.STATE_MAXIMIZED:
+        dump("STATE_MAXIMIZED \n");
+        break;
+        case win.STATE_MINIMIZED:
+        dump("STATE_MINIMIZED \n");
+        break;
+        case win.STATE_NORMAL:
+        dump("STATE_NORMAL \n");
+        break;
+      }
+      */
+
+      // Make sure size mode changes are reflected in the widget.
+      win.restore();
+      ok(win.windowState == win.STATE_NORMAL, "window state is restored.");
+      win.minimize();
+      ok(win.windowState == win.STATE_MINIMIZED, "window state is minimized.");
+      
+      // Windows resizes children to 0x0. Code in nsWindow filters these changes out. Without
+      // this all sorts of screwy things can happen in child widgets.
+      ok(document.documentElement.clientHeight > 0, "document height should not be zero for a minimized window!");
+      ok(document.documentElement.clientWidth > 0, "document width should not be zero for a minimized window!");
+      
+      // Make sure size mode changes are reflected in the widget.
+      win.restore();
+      ok(win.windowState == win.STATE_NORMAL, "window state is restored.");
+      win.maximize();
+      ok(win.windowState == win.STATE_MAXIMIZED, "window state is maximized.");
+      win.restore();
+      ok(win.windowState == win.STATE_NORMAL, "window state is restored.");
+
+      /*
+      dump(win.screenX + "\n");
+      win.minimize();
+      dump(win.screenX + "\n");
+      win.restore();
+      dump(win.screenX + "\n");
+      */
+      
+      SimpleTest.finish();
+    }
+
+  ]]>
+  </script>
+  <body xmlns="http://www.w3.org/1999/xhtml">
+    <p id="display"></p>
+    <div id="content" style="display: none"></div>
+    <pre id="test"></pre>
+  </body>
+</window>
diff --git a/widget/tests/window_wheeltransaction.xhtml b/widget/tests/window_wheeltransaction.xhtml
new file mode 100644
index 0000000000..f3c081b105
--- /dev/null
+++ b/widget/tests/window_wheeltransaction.xhtml
@@ -0,0 +1,1569 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="Wheel scroll tests"
+  width="600" height="600"
+  onload="onload();"
+  onunload="onunload();"
+  xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
+  <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js" />
+  <script src="chrome://mochikit/content/tests/SimpleTest/paint_listener.js" />
+
+<body xmlns="http://www.w3.org/1999/xhtml">
+<style type="text/css">
+  #rootview {
+    overflow: auto;
+    width: 400px;
+    height: 400px;
+    border: 1px solid;
+  }
+  #container {
+    overflow: auto;
+    width: 600px;
+    height: 600px;
+  }
+  #rootview pre {
+    margin: 20px 0 20px 20px;
+    padding: 0;
+    overflow: auto;
+    display: block;
+    width: 100px;
+    height: 100.5px;
+    font-size: 16px;
+  }
+</style>
+<div id="rootview" onscroll="onScrollView(event);">
+  <div id="container">
+    <pre id="subview1" onscroll="onScrollView(event);">
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+    </pre>
+    <pre id="subview2" onscroll="onScrollView(event);">
+Text.
+Text.
+Text.
+Text.
+Text.
+Text.
+Text.
+Text.
+Text.
+Text.
+    </pre>
+    <pre id="subview3" onscroll="onScrollView(event);">
+Text. Text. Text. Text. Text. Text. Text. Text. Text. Text. Text.
+    </pre>
+  </div>
+</div>
+<div id="content" style="display: none">
+</div>
+<pre id="test">
+</pre>
+</body>
+
+<script class="testbody" type="application/javascript">
+<![CDATA[
+
+function ok(aCondition, aMessage)
+{
+  window.arguments[0].SimpleTest.ok(aCondition, aMessage);
+}
+
+function is(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.is(aLeft, aRight, aMessage);
+}
+
+function isnot(aLeft, aRight, aMessage)
+{
+  window.arguments[0].SimpleTest.isnot(aLeft, aRight, aMessage);
+}
+
+var gCurrentTestListStatus = { nextListIndex: 0 };
+var gCurrentTest;
+
+const kListenEvent_None                 = 0;
+const kListenEvent_OnScroll             = 1;
+const kListenEvent_OnScrollFailed       = 2;
+const kListenEvent_OnTransactionTimeout = 4;
+const kListenEvent_All = kListenEvent_OnScroll |
+                         kListenEvent_OnScrollFailed |
+                         kListenEvent_OnTransactionTimeout;
+var gLitesnEvents = kListenEvent_None;
+
+/**
+ * At unexpected transaction timeout, we need to stop *all* timers.  But it is
+ * difficult and it can be create more complex testing code.  So, we should use
+ * only one timer at one time.  For that, we must store the timer id to this
+ * variable.  And the functions which may be called via a timer must clear the
+ * current timer by |_clearTimer| function.
+ */
+var gTimer;
+
+var gPrefSvc = SpecialPowers.Services.prefs;
+const kPrefSmoothScroll = "general.smoothScroll";
+const kPrefNameTimeout = "mousewheel.transaction.timeout";
+const kPrefNameIgnoreMoveDelay = "mousewheel.transaction.ignoremovedelay";
+const kPrefTestEventsAsyncEnabled = "test.events.async.enabled";
+
+const kDefaultTimeout = gPrefSvc.getIntPref(kPrefNameTimeout);
+const kDefaultIgnoreMoveDelay = gPrefSvc.getIntPref(kPrefNameIgnoreMoveDelay);
+
+gPrefSvc.setBoolPref(kPrefSmoothScroll, false);
+gPrefSvc.setBoolPref(kPrefTestEventsAsyncEnabled, true);
+
+var gTimeout, gIgnoreMoveDelay;
+var gEnoughForTimeout, gEnoughForIgnoreMoveDelay;
+
+function setTimeoutPrefs(aTimeout, aIgnoreMoveDelay)
+{
+  gPrefSvc.setIntPref(kPrefNameTimeout, aTimeout);
+  gPrefSvc.setIntPref(kPrefNameIgnoreMoveDelay, aIgnoreMoveDelay);
+  gTimeout = aTimeout;
+  gIgnoreMoveDelay = aIgnoreMoveDelay;
+  gEnoughForTimeout = gTimeout * 2;
+  gEnoughForIgnoreMoveDelay = gIgnoreMoveDelay * 1.2;
+}
+
+function resetTimeoutPrefs()
+{
+  if (gTimeout == kDefaultTimeout)
+    return;
+  setTimeoutPrefs(kDefaultTimeout, kDefaultIgnoreMoveDelay);
+  initTestList();
+}
+
+function growUpTimeoutPrefs()
+{
+  if (gTimeout != kDefaultTimeout)
+    return;
+  setTimeoutPrefs(5000, 1000);
+  initTestList();
+}
+
+// setting enough time for testing.
+gPrefSvc.setIntPref(kPrefNameTimeout, gTimeout);
+gPrefSvc.setIntPref(kPrefNameIgnoreMoveDelay, gIgnoreMoveDelay);
+
+var gRootView = document.getElementById("rootview");
+var gSubView1 = document.getElementById("subview1");
+var gSubView2 = document.getElementById("subview2");
+var gSubView3 = document.getElementById("subview3");
+
+gRootView.addEventListener("MozMouseScrollFailed", onMouseScrollFailed);
+gRootView.addEventListener("MozMouseScrollTransactionTimeout",
+                           onTransactionTimeout);
+
+function finish()
+{
+  window.close();
+}
+
+async function onload()
+{
+  // Before actually running tests, we disable auto-dir scrolling, becasue the
+  // tests in this file are meant to test scrolling transactions, not meant to
+  // test default actions for wheel events, so we simply disabled auto-dir
+  // scrolling, which are well tested in
+  // dom/events/test/window_wheel_default_action.html.
+  await SpecialPowers.pushPrefEnv({"set": [["mousewheel.autodir.enabled",
+                                            false]]});
+
+  runNextTestList();
+}
+
+function onunload()
+{
+  resetTimeoutPrefs();
+  gPrefSvc.clearUserPref(kPrefSmoothScroll);
+  gPrefSvc.clearUserPref(kPrefTestEventsAsyncEnabled);
+  disableNonTestMouseEvents(false);
+  SpecialPowers.DOMWindowUtils.restoreNormalRefresh();
+  window.arguments[0].SimpleTest.finish();
+}
+
+function offsetForRootView()
+{
+  let rootViewRect = gRootView.getBoundingClientRect();
+  let subView1Rect = gSubView1.getBoundingClientRect();
+  return {
+    x: (subView1Rect.left - rootViewRect.left) / 2,
+    y: (subView1Rect.top - rootViewRect.top) / 2,
+  }
+}
+
+function _offsetFor(aSubView)
+{
+  let rootViewRect = gRootView.getBoundingClientRect();
+  let subViewRect = aSubView.getBoundingClientRect();
+  return {
+    x: subViewRect.left - rootViewRect.left + subViewRect.width / 2,
+    y: subViewRect.top - rootViewRect.top + subViewRect.height / 2,
+  }
+}
+
+function offsetForSubView1()
+{
+  return _offsetFor(gSubView1);
+}
+
+function offsetForSubView2()
+{
+  return _offsetFor(gSubView2);
+}
+
+function offsetForSubView3()
+{
+  return _offsetFor(gSubView3);
+}
+
+/**
+ * Define the tests here:
+ *   Scrolls are processed async always.  Therefore, we need to call all tests
+ *   by timer.  gTestLists is array of testing lists. In other words, an item
+ *   of gTestList is a group of one or more testing. Each items has following
+ *   properties:
+ *
+ *     - retryWhenTransactionTimeout
+ *         The testing of wheel transaction might be fialed randomly by
+ *         timeout.  Then, automatically the failed test list will be retested
+ *         automatically only this number of times.
+ *
+ *     - steps
+ *         This property is array of testing.  Each steps must have following
+ *         properties at least.
+ *
+ *         - func
+ *             This property means function which will be called via
+ *             |setTimeout|.  The function cannot have params.  If you need
+ *             some additional parameters, you can specify some original
+ *             properties for the test function.  If you do so, you should
+ *             document it in the testing function.
+ *         - delay
+ *             This property means delay time until the function to be called.
+ *             I.e., the value used for the second param of |setTimeout|.
+ *
+ *         And also you need one more property when you call a testing function.
+ *
+ *         - description
+ *             This property is description of the test.  This is used for
+ *             logging.
+ *
+ *         At testing, you can access to current step via |gCurrentTest|.
+ */
+
+var gTestLists;
+function initTestList()
+{
+  gTestLists = [
+    /**************************************************************************
+     * Continuous scrolling test for |gRootView|
+     *   |gRootView| has both scrollbars and it has three children which are
+     *   |gSubView1|, |gSubView2| and |gSubView3|.  They have scrollbars.  If
+     *   the current transaction targets |gRootView|, other children should not
+     *   be scrolled even if the wheel events are fired on them.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Vertical case
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Vertical wheel events should scroll |gRootView| even if the position
+        // of wheel events in a child view which has scrollbar.
+        { func: testContinuousScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          description: "Continuous scrolling test for root view (vertical/forward)" },
+        { func: testContinuousScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: true, expectedView: gRootView,
+          description: "Continuous scrolling test for root view (vertical/backward)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Horizontal case
+        { func: initElements, delay: 0, forVertical: false,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Horizontal wheel events should scroll |gRootView| even if the
+        // position of wheel events in a child view which has scrollbar.
+        { func: testContinuousScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          description: "Continuous scrolling test for root view (horizontal/forward)" },
+        { func: testContinuousScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: false, expectedView: gRootView,
+          description: "Continuous scrolling test for root view (horizontal/backward)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Continuous scrolling test for |gSubView1|
+     *   |gSubView1| has both scrollbars.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Vertical case
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Vertical wheel events should scroll |gSubView1|.
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gSubView1,
+          description: "Continuous scrolling test for sub view 1 (vertical/forward)" },
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView1,
+          isForward: false, isVertical: true, expectedView: gSubView1,
+          description: "Continuous scrolling test for sub view 1 (vertical/backward)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Horizontal case
+        { func: initElements, delay: 0, forVertical: false,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Horitontal wheel events should scroll |gSubView1|.
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gSubView1,
+          description: "Continuous scrolling test for sub view 1 (horizontal/forward)" },
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView1,
+          isForward: false, isVertical: false, expectedView: gSubView1,
+          description: "Continuous scrolling test for sub view 1 (horizontal/backward)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Continuous scrolling test for |gSubView2|
+     *   |gSubView2| has only vertical scrollbar.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Vertical case
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Vertical wheel events should scroll |gSubView2|.
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView2,
+          isForward: true, isVertical: true, expectedView: gSubView2,
+          description: "Continuous scrolling test for sub view 2 (vertical/forward)" },
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView2,
+          isForward: false, isVertical: true, expectedView: gSubView2,
+          description: "Continuous scrolling test for sub view 2 (vertical/backward)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Horizontal case
+        { func: initElements, delay: 0, forVertical: false,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Horizontal wheel events should scroll its nearest scrollable ancestor
+        // view, i.e., it is |gRootView|.
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView2,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          description: "Continuous scrolling test for sub view 2 (horizontal/forward)" },
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView2,
+          isForward: false, isVertical: false, expectedView: gRootView,
+          description: "Continuous scrolling test for sub view 2 (horizontal/backward)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Continuous scrolling test for |gSubView3|
+     *   |gSubView3| has only horizontal scrollbar.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Vertical case
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Vertical wheel events should scroll its nearest scrollable ancestor
+        // view, i.e., it is |gRootView|.
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView3,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          description: "Continuous scrolling test for sub view 3 (vertical/forward)" },
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView3,
+          isForward: false, isVertical: true, expectedView: gRootView,
+          description: "Continuous scrolling test for sub view 3 (vertical/backward)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Horizontal case
+        { func: initElements, delay: 0, forVertical: false,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Horitontal wheel events should scroll |gSubView3|.
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView3,
+          isForward: true, isVertical: false, expectedView: gSubView3,
+          description: "Continuous scrolling test for sub view 3 (horizontal/forward)" },
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView3,
+          isForward: false, isVertical: false, expectedView: gSubView3,
+          description: "Continuous scrolling test for sub view 3 (horizontal/backward)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Don't reset transaction by a different direction wheel event
+     *   Even if a wheel event doesn't same direction as last wheel event, the
+     *   current transaction should not be reset.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Vertical -> Horizontal
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gRootView| by a vertical wheel
+        // event.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          description: "Don't reset transaction by a different direction wheel event (1-1)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: true, expectedView: gRootView,
+          description: "Don't reset transaction by a different direction wheel event (1-2)" },
+        // Send a horizontal wheel event over |gSubView1| but |gRootView| should
+        // be scrolled.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Don't reset transaction by a different direction wheel event (1-3)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Horizontal -> Vertical
+        { func: initElements, delay: 0, forVertical: false,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gRootView| by a horizontal wheel
+        // event.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          description: "Don't reset transaction by a different direction wheel event (2-1)" },
+        // Scroll back to left-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: false, expectedView: gRootView,
+          description: "Don't reset transaction by a different direction wheel event (2-2)" },
+        // Send a vertical wheel event over |gSubView1| but |gRootView| should
+        // be scrolled.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Don't reset transaction by a different direction wheel event (2-3)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Don't reset transaction even if a wheel event cannot scroll
+     *   Even if a wheel event cannot scroll to specified direction in the
+     *   current target view, the transaction should not be reset.  E.g., there
+     *   are some devices which can scroll obliquely.  If so, probably, users
+     *   cannot input only intended direction.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // A view only has vertical scrollbar case.
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gSubView2|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView2,
+          isForward: true, isVertical: true, expectedView: gSubView2,
+          description: "Don't reset transaction even if a wheel event cannot scroll (1-1)" },
+        // |gSubView2| doesn't have horizontal scrollbar but should not scroll
+        // any views.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView2,
+          isForward: true, isVertical: false, expectedView: null,
+          description: "Don't reset transaction even if a wheel event cannot scroll (1-2)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // A view only has horizontal scrollbar case.
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gSubView3|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView3,
+          isForward: true, isVertical: false, expectedView: gSubView3,
+          description: "Don't reset transaction even if a wheel event cannot scroll (2-1)" },
+        // |gSubView3| doesn't have vertical scrollbar but should not scroll any
+        // views.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView3,
+          isForward: true, isVertical: true, expectedView: null,
+          description: "Don't reset transaction even if a wheel event cannot scroll (2-2)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Reset transaction by mouse down/mouse up events
+     *   Mouse down and mouse up events should cause resetting the current
+     *   transaction.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Vertical case
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gRootView|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          description: "Reset transaction by mouse down/mouse up events (v-1)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: true, expectedView: gRootView,
+          description: "Reset transaction by mouse down/mouse up events (v-2)" },
+        // Send mouse button events which should reset the current transaction.
+        // So, the next wheel event should scroll |gSubView1|.
+        { func: sendMouseButtonEvents, delay: 0,
+          description: "sendMouseButtonEvents" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gSubView1,
+          description: "Reset transaction by mouse down/mouse up events (v-3)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Horizontal case
+        { func: initElements, delay: 0, forVertical: false,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gRootView|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          description: "Reset transaction by mouse down/mouse up events (h-1)" },
+        // Scroll back to left-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: false, expectedView: gRootView,
+          description: "Reset transaction by mouse down/mouse up events (h-2)" },
+        // Send mouse button events which should reset the current transaction.
+        // So, the next wheel event should scroll |gSubView1|.
+        { func: sendMouseButtonEvents, delay: 0,
+          description: "sendMouseButtonEvents" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gSubView1,
+          description: "Reset transaction by mouse down/mouse up events (h-3)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Reset transaction by a key event
+     *   A key event should cause resetting the current transaction.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Vertical case
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gRootView|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          description: "Reset transaction by a key event (v-1)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: true, expectedView: gRootView,
+          description: "Reset transaction by a key event (v-2)" },
+        // Send a key event which should reset the current transaction.  So, the
+        // next wheel event should scroll |gSubView1|.
+        { func: sendKeyEvents, delay: 0, key: "a",
+          description: "sendKeyEvents" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gSubView1,
+          description: "Reset transaction by a key event (v-3)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Horizontal case
+        { func: initElements, delay: 0, forVertical: false,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gRootView|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          description: "Reset transaction by a key event (h-1)" },
+        // Scroll back to left-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: false, expectedView: gRootView,
+          description: "Reset transaction by a key event (h-2)" },
+        // Send a key event which should reset the current transaction.  So, the
+        // next wheel event should scroll |gSubView1|.
+        { func: sendKeyEvents, delay: 0, key: "a",
+          description: "sendKeyEvents" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gSubView1,
+          description: "Reset transaction by a key event (h-3)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Reset transaction by a mouse move event
+     *   A mouse move event can cause reseting the current transaction even if
+     *   mouse cursor is inside the target view of current transaction. Only
+     *   when a wheel event is fired after |gIgnoreMoveDelay| milliseconds since
+     *   the first mouse move event from last wheel event, the transaction
+     *   should be reset.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Vertical case
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gRootView|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          description: "Reset transaction by a mouse move event (v-1)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: true, expectedView: gRootView,
+          description: "Reset transaction by a mouse move event (v-2)" },
+        // Send a mouse move event immediately after last wheel event, then,
+        // current transaction should be kept.
+        { func: sendMouseMoveEvent, delay: 0, offset: offsetForSubView1,
+          description: "sendMouseMoveEvent" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (v-3)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: false, isVertical: true, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (v-4)" },
+        // Send a mouse move event after |gIgnoreMoveDelay| milliseconds since
+        // last wheel event, then, current transaction should be kept.
+        { func: sendMouseMoveEvent, delay: gEnoughForIgnoreMoveDelay,
+          offset: offsetForSubView1,
+          description: "sendMouseMoveEvent" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (v-5)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: false, isVertical: true, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (v-6)" },
+        // Send a wheel event after |gIgnoreMoveDelay| milliseconds since last
+        // mouse move event but it is fired immediately after the last wheel
+        // event, then, current transaction should be kept.
+        { func: sendMouseMoveEvent, delay: 0, offset: offsetForSubView1,
+          description: "sendMouseMoveEvent" },
+        { func: testOneTimeScroll, delay: gEnoughForIgnoreMoveDelay,
+          offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (v-7)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: false, isVertical: true, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (v-8)" },
+        // Send a wheel event after |gIgnoreMoveDelay| milliseconds have passed
+        // since last mouse move event which is fired after |gIgnoreMoveDelay|
+        // milliseconds since last wheel event, then, current transaction should
+        // be reset.
+        { func: sendMouseMoveEvent, delay: gEnoughForIgnoreMoveDelay,
+          offset: offsetForSubView1,
+          description: "sendMouseMoveEvent" },
+        { func: testOneTimeScroll, delay: gEnoughForIgnoreMoveDelay,
+          offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gSubView1,
+          canFailRandomly: { possibleView: gRootView },
+          description: "Reset transaction by a mouse move event (v-9)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Horizontal case
+        { func: initElements, delay: 0, forVertical: false,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gRootView|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (h-1)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: false, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (h-2)" },
+        // Send a mouse move event immediately after last wheel event, then,
+        // current transaction should be kept.
+        { func: sendMouseMoveEvent, delay: 0, offset: offsetForSubView1,
+          description: "sendMouseMoveEvent" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (h-3)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: false, isVertical: false, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (h-4)" },
+        // Send a mouse move event after |gIgnoreMoveDelay| milliseconds since
+        // last wheel event, then, current transaction should be kept.
+        { func: sendMouseMoveEvent, delay: gEnoughForIgnoreMoveDelay,
+          offset: offsetForSubView1,
+          description: "sendMouseMoveEvent" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (h-5)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: false, isVertical: false, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (h-6)" },
+        // Send a wheel event after |gIgnoreMoveDelay| milliseconds since last
+        // mouse move event but it is fired immediately after the last wheel
+        // event, then, current transaction should be kept.
+        { func: sendMouseMoveEvent, delay: 0, offset: offsetForSubView1,
+          description: "sendMouseMoveEvent" },
+        { func: testOneTimeScroll, delay: gEnoughForIgnoreMoveDelay,
+          offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (h-7)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: false, isVertical: false, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Reset transaction by a mouse move event (h-8)" },
+        // Send a wheel event after |gIgnoreMoveDelay| milliseconds have passed
+        // since last mouse move event which is fired after |gIgnoreMoveDelay|
+        // milliseconds since last wheel event, then, current transaction should
+        // be reset.
+        { func: sendMouseMoveEvent, delay: gEnoughForIgnoreMoveDelay,
+          offset: offsetForSubView1,
+          description: "sendMouseMoveEvent" },
+        { func: testOneTimeScroll, delay: gEnoughForIgnoreMoveDelay,
+          offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gSubView1,
+          canFailRandomly: { possibleView: gRootView },
+          description: "Reset transaction by a mouse move event (h-9)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Reset transaction by a mouse move event on outside of view
+     *   When mouse cursor is moved to outside of the current target view, the
+     *   transaction should be reset immediately.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Vertical case
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gSubView1|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gSubView1,
+          description: "Reset transaction by a mouse move event on outside of view (v-1)" },
+        // Send mouse move event over |gRootView|.
+        { func: sendMouseMoveEvent, delay: 0, offset: offsetForRootView,
+          description: "sendMouseMoveEvent" },
+        // Send Wheel event over |gRootView| which should be scrolled.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          description: "Reset transaction by a mouse move event on outside of view (v-2)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Horizontal case
+        { func: initElements, delay: 0, forVertical: false,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Create a transaction which targets |gSubView1|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gSubView1,
+          description: "Reset transaction by a mouse move event on outside of view (h-1)" },
+        // Send mouse move event over |gRootView|.
+        { func: sendMouseMoveEvent, delay: 0, offset: offsetForRootView,
+          description: "sendMouseMoveEvent" },
+        // Send Wheel event over |gRootView| which should be scrolled.
+        { func: testOneTimeScroll, delay: 0,  offset: offsetForRootView,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          description: "Reset transaction by a mouse move event on outside of view (h-2)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Timeout test
+     *   A view should not be scrolled during another to be transaction for
+     *   another view scrolling. However, a wheel event which is sent after
+     *   timeout, a view which is under the mouse cursor should be scrolled.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Vertical case
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // First, create a transaction which should target the |gRootView|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          description: "Timeout test (v-1)" },
+        // Scroll back to top-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: true, expectedView: gRootView,
+          description: "Timeout test (v-2)" },
+        // A wheel event over |gSubView1| should not scroll it during current
+        // transaction.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Timeout test (v-3)" },
+        // Scroll back to top-most again.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: false, isVertical: true, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Timeout test (v-4)" },
+        // A wheel event over |gSubView1| after timeout should scroll
+        // |gSubView1|.
+        { func: testOneTimeScroll, delay: gEnoughForTimeout,
+          offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gSubView1,
+          isTimeoutTesting: true,
+          description: "Timeout test (v-5)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Horizontal case
+        { func: initElements, delay: 0, forVertical: false,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // First, create a transaction which should target the |gRootView|.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          description: "Timeout test (h-1)" },
+        // Scroll back to left-most for easy cursor position specifying.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForRootView,
+          isForward: false, isVertical: false, expectedView: gRootView,
+          description: "Timeout test (h-2)" },
+        // A wheel event over |gSubView1| should not scroll it during current
+        // transaction.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Timeout test (h-3)" },
+        // Scroll back to left-most again.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: false, isVertical: false, expectedView: gRootView,
+          canFailRandomly: { possibleView: gSubView1 },
+          description: "Timeout test (h-4)" },
+        // A wheel event over |gSubView1| after timeout should scroll
+        // |gSubView1|.
+        { func: testOneTimeScroll, delay: gEnoughForTimeout,
+          offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gSubView1,
+          isTimeoutTesting: true,
+          description: "Timeout test (h-5)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Timeout test even with many wheel events
+     *   This tests whether timeout is occurred event if wheel events are sent.
+     *   The transaction should not be updated by non-scrollable wheel events.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Vertical case
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Scroll |gSubView1| to bottom-most.
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gSubView1,
+          description: "Timeout test even with many wheel events (v-1)" },
+        // Don't scroll any views before timeout.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: null,
+          canFailRandomly: { possibleView: gRootView },
+          description: "Timeout test even with many wheel events (v-2)" },
+        // Recreate a transaction which is scrolling |gRootView| after time out.
+        { func: testRestartScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gRootView,
+          description: "Timeout test even with many wheel events (v-3)" }
+      ]
+    },
+
+
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        // Horizontal case
+        { func: initElements, delay: 0, forVertical: false,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        // Scroll |gSubView1| to right-most.
+        { func: testContinuousScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gSubView1,
+          description: "Timeout test even with many wheel events (h-1)" },
+        // Don't scroll any views before timeout.
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: null,
+          canFailRandomly: { possibleView: gRootView },
+          description: "Timeout test even with many wheel events (h-2)" },
+        // Recreate a transaction which is scrolling |gRootView| after time out.
+        { func: testRestartScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gRootView,
+          description: "Timeout test even with many wheel events (h-3)" }
+      ]
+    },
+
+
+    /**************************************************************************
+     * Very large scrolling wheel event
+     *   If the delta value is larger than the scrolling page size, it should be
+     *   scrolled only one page instead of the delta value.
+     **************************************************************************/
+    { retryWhenTransactionTimeout: 5,
+      steps: [
+        { func: initElements, delay: 0, forVertical: true,
+          description: "initElements" },
+        { func: clearWheelTransaction, delay: 0,
+          description: "clearWheelTransaction" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gSubView1,
+          delta: 5000,
+          description: "Very large delta scrolling (v-1)" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: true, expectedView: gSubView1,
+          delta: 5000,
+          description: "Very large delta scrolling (v-2)" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gSubView1,
+          delta: 5000,
+          description: "Very large delta scrolling (h-1)" },
+        { func: testOneTimeScroll, delay: 0, offset: offsetForSubView1,
+          isForward: true, isVertical: false, expectedView: gSubView1,
+          delta: 5000,
+          description: "Very large delta scrolling (h-2)" }
+      ]
+    }
+  ];
+}
+
+/******************************************************************************
+ * Actions for preparing tests
+ ******************************************************************************/
+
+function initElements()
+{
+  _clearTimer();
+
+  function resetScrollPosition(aElement)
+  {
+    aElement.scrollTop = 0;
+    aElement.scrollLeft = 0;
+  }
+
+  const kDisplay = gCurrentTest.forVertical ? "block" : "inline-block";
+  gSubView1.style.display = kDisplay;
+  gSubView2.style.display = kDisplay;
+  gSubView3.style.display = kDisplay;
+
+  resetScrollPosition(gRootView);
+  resetScrollPosition(gSubView1);
+  resetScrollPosition(gSubView2);
+  resetScrollPosition(gSubView3);
+  _getDOMWindowUtils(window).advanceTimeAndRefresh(0);
+
+  runNextTestStep();
+}
+
+function clearWheelTransaction()
+{
+  _clearTimer();
+  _clearTransaction();
+  runNextTestStep();
+}
+
+function sendKeyEvents()
+{
+  _clearTimer();
+  synthesizeKey(gCurrentTest.key, {}, window);
+  runNextTestStep();
+}
+
+function sendMouseButtonEvents()
+{
+  _clearTimer();
+  synthesizeMouse(gRootView, -1, -1, { type:"mousedown" }, window);
+  synthesizeMouse(gRootView, -1, -1, { type:"mouseup" }, window);
+  runNextTestStep();
+}
+
+function sendMouseMoveEvent()
+{
+  _clearTimer();
+  _fireMouseMoveEvent(gCurrentTest.offset());
+  runNextTestStep();
+}
+
+/******************************************************************************
+ * Utilities for testing functions
+ ******************************************************************************/
+
+function _clearTransaction()
+{
+  synthesizeMouse(gRootView, -1, -1, { type:"mousedown" }, window);
+  synthesizeMouse(gRootView, -1, -1, { type:"mouseup" }, window);
+}
+
+function _saveScrollPositions()
+{
+  function save(aElement)
+  {
+    aElement.prevTop = aElement.scrollTop;
+    aElement.prevLeft = aElement.scrollLeft;
+  }
+  save(gRootView);
+  save(gSubView1);
+  save(gSubView2);
+  save(gSubView3);
+}
+
+function _fireMouseMoveEvent(aOffset)
+{
+  synthesizeMouse(gRootView, aOffset.x, aOffset.y, { type:"mousemove" }, window);
+}
+
+function _fireWheelScrollEvent(aOffset, aIsVertical, aForward, aDelta)
+{
+  var event = { deltaMode: WheelEvent.DOM_DELTA_LINE };
+  if (aIsVertical) {
+    event.deltaY = aForward ? aDelta : -aDelta;
+  } else {
+    event.deltaX = aForward ? aDelta : -aDelta;
+  }
+  sendWheelAndPaint(gRootView, aOffset.x, aOffset.y, event, null, window);
+}
+
+function _canScroll(aElement, aIsVertical, aForward)
+{
+  if (aIsVertical) {
+    if (!aForward)
+      return aElement.scrollTop > 0;
+    return aElement.scrollHeight > aElement.scrollTop + aElement.clientHeight;
+  }
+  if (!aForward)
+    return aElement.scrollLeft > 0;
+  return aElement.scrollWidth > aElement.scrollLeft + aElement.clientWidth;
+}
+
+const kNotScrolled      = 0;
+const kScrolledToTop    = 1;
+const kScrolledToBottom = 2;
+const kScrolledToLeft   = 4;
+const kScrolledToRight  = 8;
+
+const kScrolledVertical   = kScrolledToTop | kScrolledToBottom;
+const kScrolledHorizontal = kScrolledToLeft | kScrolledToRight;
+
+function _getScrolledState(aElement)
+{
+  var ret = kNotScrolled;
+  if (aElement.scrollTop != aElement.prevTop) {
+    ret |= aElement.scrollTop < aElement.prevTop ? kScrolledToTop :
+                                                   kScrolledToBottom;
+  }
+  if (aElement.scrollLeft != aElement.prevLeft) {
+    ret |= aElement.scrollLeft < aElement.prevLeft ? kScrolledToLeft :
+                                                     kScrolledToRight;
+  }
+  return ret;
+}
+
+function _getExpectedScrolledState()
+{
+  // eslint-disable-next-line no-nested-ternary
+  return gCurrentTest.isVertical ?
+           gCurrentTest.isForward ? kScrolledToBottom : kScrolledToTop :
+           gCurrentTest.isForward ? kScrolledToRight : kScrolledToLeft;
+}
+
+function _getScrolledStateText(aScrolledState)
+{
+  if (aScrolledState == kNotScrolled)
+    return "Not scrolled";
+
+  var s = "scrolled to ";
+  if (aScrolledState & kScrolledVertical) {
+    s += aScrolledState & kScrolledToTop ? "backward" : "forward";
+    s += " (vertical)"
+    if (aScrolledState & kScrolledHorizontal)
+      s += " and to ";
+  }
+  if (aScrolledState & kScrolledHorizontal) {
+    s += aScrolledState & kScrolledToLeft ? "backward" : "forward";
+    s += " (horizontal)"
+  }
+  return s;
+}
+
+function _getCurrentTestList()
+{
+  return gTestLists[gCurrentTestListStatus.nextListIndex - 1];
+}
+
+function _clearTimer()
+{
+  clearTimeout(gTimer);
+  gTimer = 0;
+}
+
+/******************************************************************************
+ * Testing functions
+ ******************************************************************************/
+
+/**
+ * Note that testing functions must set following variables:
+ *
+ *   gCurrentTest.repeatTest:  See comment in |continueTest|.
+ *   gCurrentTest.autoRepeatDelay:  See comment in |continueTest|.
+ *   gListenScrollEvent: When this is not true, the event handlers ignores the
+ *                       events.
+ */
+
+function testContinuousScroll()
+{
+  /**
+   * Testing continuous scrolling.  This function synthesizes a wheel event.  If
+   * the test was success, this function will be recalled automatically.
+   * And when a generating wheel event cannot scroll the expected view, this
+   * function fires the wheel event only one time.
+   *
+   * @param gCurrentTest.offset
+   *          A function to compute the cursor position of firing wheel event.
+   *          The values are offset from |gRootView|.
+   * @param gCurrentTest.isVertical
+   *          Whether the wheel event is for virtical scrolling or horizontal.
+   * @param gCurrentTest.isForward
+   *          Whether the wheel event is to forward or to backward.
+   * @param gCurrentTest.expectedView
+   *          The expected view which will be scrolled by wheel event. This
+   *          value must not be null.
+   */
+
+  _clearTimer();
+  _saveScrollPositions();
+  if (!gCurrentTest.expectedView) {
+    runNextTestStep();
+    return;
+  }
+
+  gLitesnEvents = kListenEvent_All;
+  gCurrentTest.repeatTest = true;
+  gCurrentTest.autoRepeatDelay = 0;
+
+  if (!_canScroll(gCurrentTest.expectedView,
+                  gCurrentTest.isVertical, gCurrentTest.isForward)) {
+    gCurrentTest.expectedView = null;
+  }
+  var delta = gCurrentTest.delta ? gCurrentTest.delta : 4;
+  _fireWheelScrollEvent(gCurrentTest.offset(),
+                        gCurrentTest.isVertical, gCurrentTest.isForward, delta);
+}
+
+function testOneTimeScroll()
+{
+  /**
+   * Testing one wheel event.  |runNextTestStep| will be called immediately
+   * after this function by |onScrollView| or |onTimeout|.
+   *
+   * @param gCurrentTest.offset
+   *          A function to compute the cursor position of firing wheel event.
+   *          The values are offset from |gRootView|.
+   * @param gCurrentTest.isVertical
+   *          Whether the wheel event is for virtical scrolling or horizontal.
+   * @param gCurrentTest.isForward
+   *          Whether the wheel event is to forward or to backward.
+   * @param gCurrentTest.expectedView
+   *          The expected view which will be scrolled by wheel event. This
+   *          value can be null.  It means any views should not be scrolled.
+   */
+
+  _clearTimer();
+  _saveScrollPositions();
+
+  gLitesnEvents = kListenEvent_All;
+  gCurrentTest.repeatTest = false;
+  gCurrentTest.autoRepeatDelay = 0;
+
+  var delta = gCurrentTest.delta ? gCurrentTest.delta : 4;
+  _fireWheelScrollEvent(gCurrentTest.offset(),
+                        gCurrentTest.isVertical, gCurrentTest.isForward, delta);
+}
+
+function testRestartScroll()
+{
+  /**
+   * Testing restart to scroll in expected view after timeout from the current
+   * transaction.  This function recall this itself until to success this test
+   * or timeout from this test.
+   *
+   * @param gCurrentTest.offset
+   *          A function to compute the cursor position of firing wheel event.
+   *          The values are offset from |gRootView|.
+   * @param gCurrentTest.isVertical
+   *          Whether the wheel event is for virtical scrolling or horizontal.
+   * @param gCurrentTest.isForward
+   *          Whether the wheel event is to forward or to backward.
+   * @param gCurrentTest.expectedView
+   *          The expected view which will be scrolled by wheel event. This
+   *          value must not be null.
+   */
+
+  _clearTimer();
+  _saveScrollPositions();
+
+  if (!gCurrentTest.wasTransactionTimeout) {
+    gCurrentTest.repeatTest = true;
+    gCurrentTest.autoRepeatDelay = gTimeout / 3;
+    gLitesnEvents = kListenEvent_All;
+    gCurrentTest.isTimeoutTesting = true;
+    if (gCurrentTest.expectedView) {
+      gCurrentTest.expectedViewAfterTimeout = gCurrentTest.expectedView;
+      gCurrentTest.expectedView = null;
+    }
+  } else {
+    gCurrentTest.repeatTest = false;
+    gCurrentTest.autoRepeatDelay = 0;
+    gLitesnEvents = kListenEvent_All;
+    gCurrentTest.isTimeoutTesting = false;
+    gCurrentTest.expectedView = gCurrentTest.expectedViewAfterTimeout;
+  }
+
+  var delta = gCurrentTest.delta ? gCurrentTest.delta : 4;
+  _fireWheelScrollEvent(gCurrentTest.offset(),
+                        gCurrentTest.isVertical, gCurrentTest.isForward, delta);
+}
+
+/******************************************************************************
+ * Event handlers
+ ******************************************************************************/
+
+function onScrollView(aEvent)
+{
+  /**
+   * Scroll event handler of |gRootView|, |gSubView1|, |gSubView2| and 
+   * |gSubView3|.  If testing is failed, this function cancels all left tests.
+   * For checking the event is expected, the event firer must call
+   * |_saveScrollPositions|.
+   *
+   * @param gCurrentTest.expectedView
+   *          The expected view which should be scrolled by the wheel event.
+   *          This value can be null.  It means any views should not be
+   *          scrolled.
+   * @param gCurrentTest.isVertical
+   *          The expected view should be scrolled vertical or horizontal.
+   * @param gCurrentTest.isForward
+   *          The expected view should be scrolled to forward or backward.
+   * @param gCurrentTest.canFailRandomly
+   *          If this is not undefined, this test can fail by unexpected view
+   *          scrolling which is caused by unexpected timeout.  If this is
+   *          defined, |gCurrentTest.possibleView| must be set.  If the view is
+   *          same as the event target, the failure can be random.  At this
+   *          time, we should retry the current test list.
+   */
+
+  if (!(gLitesnEvents & kListenEvent_OnScroll))
+    return;
+
+  // Now testing a timeout, but a view is scrolled before timeout.
+  if (gCurrentTest.isTimeoutTesting && !gCurrentTest.wasTransactionTimeout) {
+    is(aEvent.target.id, "",
+       "The view scrolled before timeout (the expected view after timeout is " +
+         gCurrentTest.expectedView ? gCurrentTest.expectedView.id : "null" +
+         "): " + gCurrentTest.description);
+    runNextTestList();
+    return;
+  }
+
+  // Check whether the scrolled event should be fired or not.
+  if (!gCurrentTest.expectedView) {
+    is(aEvent.target.id, "",
+         "no views should be scrolled (" +
+         _getScrolledStateText(_getScrolledState(aEvent.target)) + "): " +
+         gCurrentTest.description);
+    runNextTestList();
+    return;
+  }
+
+  // Check whether the scrolled view is expected or not.
+  if (aEvent.target != gCurrentTest.expectedView) {
+    // If current test can fail randomly and the possible view is same as the
+    // event target, this failure may be caused by unexpected timeout.
+    // At this time, we should retry the current tests with slower settings.
+    if (gCurrentTest.canFailRandomly &&
+        gCurrentTest.canFailRandomly.possibleView == aEvent.target &&
+        gCurrentTestListStatus.retryWhenTransactionTimeout > 0) {
+      gCurrentTestListStatus.retryWhenTransactionTimeout--;
+      retryCurrentTestList();
+      return;
+    }
+    is(aEvent.target.id, gCurrentTest.expectedView.id,
+       "wrong view was scrolled: " + gCurrentTest.description);
+    runNextTestList();
+    return;
+  }
+
+  // Check whether the scrolling direction is expected or not.
+  var expectedState = _getExpectedScrolledState();
+  var currentState = _getScrolledState(aEvent.target);
+  if (expectedState != currentState) {
+    is(_getScrolledStateText(currentState),
+       _getScrolledStateText(expectedState),
+       "scrolled to wrong direction: " + gCurrentTest.description);
+    runNextTestList();
+    return;
+  }
+
+  ok(true, "passed: " + gCurrentTest.description);
+  continueTest();
+}
+
+function onMouseScrollFailed()
+{
+  /**
+   * Scroll failed event handler. If testing is failed, this function cancels
+   * all remains of current test-list, and go to next test-list.
+   *
+   * NOTE: This event is fired immediately after |_fireWheelScrollEvent|.
+   *
+   * @param gCurrentTest.expectedView
+   *          The expected view which should be scrolled by the wheel event.
+   *          This value can be null.  It means any views should not be
+   *          scrolled.  When this is not null, this event means the test may
+   *          be failed.
+   */
+
+  if (!(gLitesnEvents & kListenEvent_OnScrollFailed))
+    return;
+
+  ok(!gCurrentTest.expectedView,
+     "failed to scroll on current target: " + gCurrentTest.description);
+  if (gCurrentTest.expectedView) {
+    runNextTestList();
+    return;
+  }
+
+  continueTest();
+}
+
+function onTransactionTimeout()
+{
+  /**
+   * Scroll transaction timeout event handler.  If the timeout is unexpected,
+   * i.e., |gCurrentTest.isTimeoutTesting| is not true, this function retry
+   * the current test-list.  However, if the current test-list failed by timeout
+   * |gCurrentTestListStatus.retryWhenTransactionTimeout| times already, marking
+   * to failed the current test-list, and go to next test-list.
+   *
+   * @param gCurrentTest.expectedView
+   *          The expected view which should be scrolled by the wheel event.
+   *          This value can be null.  It means any views should not be
+   *          scrolled.  When this is not null, this event means the testing may
+   *          be failed.
+   * @param gCurrentTest.isTimeoutTesting
+   *          If this value is true, the current testing have waited this
+   *          event.  Otherwise, the testing may be failed.
+   * @param gCurrentTestListStatus.retryWhenTransactionTimeout
+   *          If |gCurrentTest.isTimeoutTesting| is not true but this event is
+   *          fired, the failure may be randomly.  Then, this event handler
+   *          retry to test the current test-list until this cound will be zero.
+   */
+
+  if (!gCurrentTest.isTimeoutTesting &&
+      gCurrentTestListStatus.retryWhenTransactionTimeout > 0) {
+    gCurrentTestListStatus.retryWhenTransactionTimeout--;
+    // retry current test list
+    retryCurrentTestList();
+    return;
+  }
+
+  gCurrentTest.wasTransactionTimeout = true;
+
+  if (!(gLitesnEvents & kListenEvent_OnTransactionTimeout))
+    return;
+
+  ok(gCurrentTest.isTimeoutTesting,
+     "transaction timeout: " + gCurrentTest.description);
+  if (!gCurrentTest.isTimeoutTesting) {
+    runNextTestList();
+    return;
+  }
+
+  continueTest();
+}
+
+/******************************************************************************
+ * Main function for this tests
+ ******************************************************************************/
+
+function runNextTestStep()
+{
+  // When this is first time or the current test list is finised, load next
+  // test-list.
+  _clearTimer();
+  if (!gCurrentTest)
+    runNextTestList();
+  else
+    runTestStepAt(gCurrentTestListStatus.nextStepIndex);
+}
+
+function runNextTestList()
+{
+  _clearTimer();
+
+  gLitesnEvents = kListenEvent_None;
+  _clearTransaction();
+  resetTimeoutPrefs();
+  if (gCurrentTestListStatus.nextListIndex >= gTestLists.length) {
+    finish();
+    return;
+  }
+
+  gCurrentTestListStatus.nextListIndex++;
+  gCurrentTestListStatus.retryWhenTransactionTimeout =
+    _getCurrentTestList().retryWhenTransactionTimeout;
+  runTestStepAt(0);
+}
+
+function runTestStepAt(aStepIndex)
+{
+  _clearTimer();
+
+  disableNonTestMouseEvents(true);
+
+  // load a step of testing.
+  gCurrentTestListStatus.nextStepIndex = aStepIndex;
+  gCurrentTest =
+    _getCurrentTestList().steps[gCurrentTestListStatus.nextStepIndex++];
+  if (gCurrentTest) {
+    gCurrentTest.wasTransactionTimeout = false;
+    gTimer = setTimeout(gCurrentTest.func, gCurrentTest.delay);
+  } else {
+    // If current test-list doesn't have more testing, go to next test-list
+    // after cleaning up the current transaction.
+    _clearTransaction();
+    runNextTestList();
+  }
+}
+
+function retryCurrentTestList()
+{
+  _clearTimer();
+
+  gLitesnEvents = kListenEvent_None;
+  _clearTransaction();
+  ok(true, "WARNING: retry current test-list...");
+  growUpTimeoutPrefs(); // retry the test with longer timeout settings.
+  runTestStepAt(0);
+}
+
+function continueTest()
+{
+  /**
+   * This function is called from an event handler when a test succeeded.
+   *
+   * @param gCurrentTest.repeatTest
+   *          When this is true, onScrollView calls |gCurrentTest.func|. So,
+   *          same test can repeat.  Otherwise, this calls |runNextTestStep|.
+   * @param gCurrentTest.autoRepeatDelay
+   *          The delay value in milliseconds, this is used to call
+   *          |gCurrentTest.func| via |setTimeout|.
+   */
+
+  _clearTimer();
+  gLitesnEvents = kListenEvent_OnTransactionTimeout;
+
+  // We should call each functions via setTimeout. Because sometimes this test
+  // is broken by stack overflow.
+  if (gCurrentTest.repeatTest) {
+    gTimer = setTimeout(gCurrentTest.func, gCurrentTest.autoRepeatDelay);
+  } else {
+    gTimer = setTimeout(runNextTestStep, 0);
+  }
+}
+
+]]>
+</script>
+
+</window>
diff --git a/widget/uikit/GfxInfo.cpp b/widget/uikit/GfxInfo.cpp
new file mode 100644
index 0000000000..d797e4f4a0
--- /dev/null
+++ b/widget/uikit/GfxInfo.cpp
@@ -0,0 +1,174 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GfxInfo.h"
+#include "nsServiceManagerUtils.h"
+
+namespace mozilla {
+namespace widget {
+
+#ifdef DEBUG
+NS_IMPL_ISUPPORTS_INHERITED(GfxInfo, GfxInfoBase, nsIGfxInfoDebug)
+#endif
+
+GfxInfo::GfxInfo() {}
+
+GfxInfo::~GfxInfo() {}
+
+nsresult GfxInfo::GetD2DEnabled(bool* aEnabled) { return NS_ERROR_FAILURE; }
+
+nsresult GfxInfo::GetDWriteEnabled(bool* aEnabled) { return NS_ERROR_FAILURE; }
+
+NS_IMETHODIMP
+GfxInfo::GetDWriteVersion(nsAString& aDwriteVersion) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetCleartypeParameters(nsAString& aCleartypeParams) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDescription(nsAString& aAdapterDescription) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDescription2(nsAString& aAdapterDescription) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterRAM(uint32_t* aAdapterRAM) { return NS_ERROR_FAILURE; }
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterRAM2(uint32_t* aAdapterRAM) { return NS_ERROR_FAILURE; }
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriver(nsAString& aAdapterDriver) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriver2(nsAString& aAdapterDriver) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVersion(nsAString& aAdapterDriverVersion) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVersion2(nsAString& aAdapterDriverVersion) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverDate(nsAString& aAdapterDriverDate) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverDate2(nsAString& aAdapterDriverDate) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterVendorID(nsAString& aAdapterVendorID) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterVendorID2(nsAString& aAdapterVendorID) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDeviceID(nsAString& aAdapterDeviceID) {
+  return NS_ERROR_FAILURE;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDeviceID2(nsAString& aAdapterDeviceID) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterSubsysID(nsAString& aAdapterSubsysID) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterSubsysID2(nsAString& aAdapterSubsysID) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetIsGPU2Active(bool* aIsGPU2Active) { return NS_ERROR_FAILURE; }
+
+const nsTArray<GfxDriverInfo>& GfxInfo::GetGfxDriverInfo() {
+  if (sDriverInfo->IsEmpty()) {
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Ios, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_OPENGL_LAYERS, nsIGfxInfo::FEATURE_STATUS_OK,
+        DRIVER_COMPARISON_IGNORED, GfxDriverInfo::allDriverVersions);
+  }
+
+  return *sDriverInfo;
+}
+
+nsresult GfxInfo::GetFeatureStatusImpl(
+    int32_t aFeature, int32_t* aStatus, nsAString& aSuggestedDriverVersion,
+    const nsTArray<GfxDriverInfo>& aDriverInfo,
+    OperatingSystem* aOS /* = nullptr */) {
+  NS_ENSURE_ARG_POINTER(aStatus);
+  aSuggestedDriverVersion.SetIsVoid(true);
+  *aStatus = nsIGfxInfo::FEATURE_STATUS_UNKNOWN;
+  if (aOS) *aOS = OperatingSystem::Ios;
+
+  if (sShutdownOccurred) {
+    return NS_OK;
+  }
+
+  // OpenGL layers are never blocklisted on iOS.
+  // This early return is so we avoid potentially slow
+  // GLStrings initialization on startup when we initialize GL layers.
+  if (aFeature == nsIGfxInfo::FEATURE_OPENGL_LAYERS ||
+      aFeature == nsIGfxInfo::FEATURE_WEBGL_OPENGL) {
+    *aStatus = nsIGfxInfo::FEATURE_STATUS_OK;
+    return NS_OK;
+  }
+
+  return GfxInfoBase::GetFeatureStatusImpl(
+      aFeature, aStatus, aSuggestedDriverVersion, aDriverInfo, aOS);
+}
+
+#ifdef DEBUG
+
+// Implement nsIGfxInfoDebug
+
+NS_IMETHODIMP GfxInfo::SpoofVendorID(const nsAString& aVendorID) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofDeviceID(const nsAString& aDeviceID) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofDriverVersion(const nsAString& aDriverVersion) {
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofOSVersion(uint32_t aVersion) {
+  return NS_ERROR_FAILURE;
+}
+
+#endif
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/uikit/GfxInfo.h b/widget/uikit/GfxInfo.h
new file mode 100644
index 0000000000..fe75e28d23
--- /dev/null
+++ b/widget/uikit/GfxInfo.h
@@ -0,0 +1,75 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_GfxInfo_h__
+#define __mozilla_widget_GfxInfo_h__
+
+#include "GfxInfoBase.h"
+#include "GfxDriverInfo.h"
+
+#include "nsString.h"
+#include "mozilla/UniquePtr.h"
+
+namespace mozilla {
+
+namespace gl {
+class GLContext;
+}
+
+namespace widget {
+
+class GfxInfo : public GfxInfoBase {
+ private:
+  ~GfxInfo();
+
+ public:
+  GfxInfo();
+
+  // We only declare the subset of nsIGfxInfo that we actually implement. The
+  // rest is brought forward from GfxInfoBase.
+  NS_IMETHOD GetD2DEnabled(bool* aD2DEnabled) override;
+  NS_IMETHOD GetDWriteEnabled(bool* aDWriteEnabled) override;
+  NS_IMETHOD GetDWriteVersion(nsAString& aDwriteVersion) override;
+  NS_IMETHOD GetCleartypeParameters(nsAString& aCleartypeParams) override;
+  NS_IMETHOD GetAdapterDescription(nsAString& aAdapterDescription) override;
+  NS_IMETHOD GetAdapterDriver(nsAString& aAdapterDriver) override;
+  NS_IMETHOD GetAdapterVendorID(nsAString& aAdapterVendorID) override;
+  NS_IMETHOD GetAdapterDeviceID(nsAString& aAdapterDeviceID) override;
+  NS_IMETHOD GetAdapterSubsysID(nsAString& aAdapterSubsysID) override;
+  NS_IMETHOD GetAdapterRAM(uint32_t* aAdapterRAM) override;
+  NS_IMETHOD GetAdapterDriverVersion(nsAString& aAdapterDriverVersion) override;
+  NS_IMETHOD GetAdapterDriverDate(nsAString& aAdapterDriverDate) override;
+  NS_IMETHOD GetAdapterDescription2(nsAString& aAdapterDescription) override;
+  NS_IMETHOD GetAdapterDriver2(nsAString& aAdapterDriver) override;
+  NS_IMETHOD GetAdapterVendorID2(nsAString& aAdapterVendorID) override;
+  NS_IMETHOD GetAdapterDeviceID2(nsAString& aAdapterDeviceID) override;
+  NS_IMETHOD GetAdapterSubsysID2(nsAString& aAdapterSubsysID) override;
+  NS_IMETHOD GetAdapterRAM2(uint32_t* aAdapterRAM) override;
+  NS_IMETHOD GetAdapterDriverVersion2(
+      nsAString& aAdapterDriverVersion) override;
+  NS_IMETHOD GetAdapterDriverDate2(nsAString& aAdapterDriverDate) override;
+  NS_IMETHOD GetIsGPU2Active(bool* aIsGPU2Active) override;
+  using GfxInfoBase::GetFeatureStatus;
+  using GfxInfoBase::GetFeatureSuggestedDriverVersion;
+
+#ifdef DEBUG
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIGFXINFODEBUG
+#endif
+
+ protected:
+  virtual nsresult GetFeatureStatusImpl(
+      int32_t aFeature, int32_t* aStatus, nsAString& aSuggestedDriverVersion,
+      const nsTArray<GfxDriverInfo>& aDriverInfo,
+      OperatingSystem* aOS = nullptr);
+  virtual const nsTArray<GfxDriverInfo>& GetGfxDriverInfo();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __mozilla_widget_GfxInfo_h__ */
diff --git a/widget/uikit/moz.build b/widget/uikit/moz.build
new file mode 100644
index 0000000000..6a3c2db994
--- /dev/null
+++ b/widget/uikit/moz.build
@@ -0,0 +1,24 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "Widget")
+
+SOURCES += [
+    "GfxInfo.cpp",
+    "nsAppShell.mm",
+    "nsLookAndFeel.mm",
+    "nsScreenManager.mm",
+    "nsWidgetFactory.mm",
+    "nsWindow.mm",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
+LOCAL_INCLUDES += [
+    "/widget",
+]
diff --git a/widget/uikit/nsAppShell.h b/widget/uikit/nsAppShell.h
new file mode 100644
index 0000000000..fd46a51025
--- /dev/null
+++ b/widget/uikit/nsAppShell.h
@@ -0,0 +1,56 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Runs the main native UIKit run loop, interrupting it as needed to process
+ * Gecko events.
+ */
+
+#ifndef nsAppShell_h_
+#define nsAppShell_h_
+
+#include "nsBaseAppShell.h"
+#include "nsTArray.h"
+
+#include <Foundation/NSAutoreleasePool.h>
+#include <CoreFoundation/CFRunLoop.h>
+#include <UIKit/UIWindow.h>
+
+@class AppShellDelegate;
+
+class nsAppShell : public nsBaseAppShell {
+ public:
+  NS_IMETHOD ResumeNative(void) override;
+
+  nsAppShell();
+
+  nsresult Init();
+
+  NS_IMETHOD Run(void) override;
+  NS_IMETHOD Exit(void) override;
+  // Called by the application delegate
+  void WillTerminate(void);
+
+  static nsAppShell* gAppShell;
+  static UIWindow* gWindow;
+  static NSMutableArray* gTopLevelViews;
+
+ protected:
+  virtual ~nsAppShell();
+
+  static void ProcessGeckoEvents(void* aInfo);
+  virtual void ScheduleNativeEventCallback();
+  virtual bool ProcessNextNativeEvent(bool aMayWait);
+
+  NSAutoreleasePool* mAutoreleasePool;
+  AppShellDelegate* mDelegate;
+  CFRunLoopRef mCFRunLoop;
+  CFRunLoopSourceRef mCFRunLoopSource;
+
+  bool mTerminated;
+  bool mNotifiedWillTerminate;
+};
+
+#endif  // nsAppShell_h_
diff --git a/widget/uikit/nsAppShell.mm b/widget/uikit/nsAppShell.mm
new file mode 100644
index 0000000000..6324a04b4d
--- /dev/null
+++ b/widget/uikit/nsAppShell.mm
@@ -0,0 +1,243 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <UIKit/UIApplication.h>
+#import <UIKit/UIScreen.h>
+#import <UIKit/UIWindow.h>
+#import <UIKit/UIViewController.h>
+
+#include "nsAppShell.h"
+#include "nsCOMPtr.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsString.h"
+#include "nsIRollupListener.h"
+#include "nsIWidget.h"
+#include "nsThreadUtils.h"
+#include "nsMemoryPressure.h"
+#include "nsServiceManagerUtils.h"
+
+nsAppShell* nsAppShell::gAppShell = NULL;
+UIWindow* nsAppShell::gWindow = nil;
+NSMutableArray* nsAppShell::gTopLevelViews = [[NSMutableArray alloc] init];
+
+#define ALOG(args...)    \
+  fprintf(stderr, args); \
+  fprintf(stderr, "\n")
+
+// ViewController
+@interface ViewController : UIViewController
+@end
+
+@implementation ViewController
+
+- (void)loadView {
+  ALOG("[ViewController loadView]");
+  CGRect r = {{0, 0}, {100, 100}};
+  self.view = [[UIView alloc] initWithFrame:r];
+  [self.view setBackgroundColor:[UIColor lightGrayColor]];
+  // add all of the top level views as children
+  for (UIView* v in nsAppShell::gTopLevelViews) {
+    ALOG("[ViewController.view addSubView:%p]", v);
+    [self.view addSubview:v];
+  }
+  [nsAppShell::gTopLevelViews release];
+  nsAppShell::gTopLevelViews = nil;
+}
+@end
+
+// AppShellDelegate
+//
+// Acts as a delegate for the UIApplication
+
+@interface AppShellDelegate : NSObject <UIApplicationDelegate> {
+}
+@property(strong, nonatomic) UIWindow* window;
+@end
+
+@implementation AppShellDelegate
+
+- (BOOL)application:(UIApplication*)application
+    didFinishLaunchingWithOptions:(NSDictionary*)launchOptions {
+  ALOG("[AppShellDelegate application:didFinishLaunchingWithOptions:]");
+  // We only create one window, since we can only display one window at
+  // a time anyway. Also, iOS 4 fails to display UIWindows if you
+  // create them before calling UIApplicationMain, so this makes more sense.
+  nsAppShell::gWindow = [[[UIWindow alloc]
+      initWithFrame:[[UIScreen mainScreen] applicationFrame]] retain];
+  self.window = nsAppShell::gWindow;
+
+  self.window.rootViewController = [[ViewController alloc] init];
+
+  // just to make things more visible for now
+  nsAppShell::gWindow.backgroundColor = [UIColor blueColor];
+  [nsAppShell::gWindow makeKeyAndVisible];
+
+  return YES;
+}
+
+- (void)applicationWillTerminate:(UIApplication*)application {
+  ALOG("[AppShellDelegate applicationWillTerminate:]");
+  nsAppShell::gAppShell->WillTerminate();
+}
+
+- (void)applicationDidBecomeActive:(UIApplication*)application {
+  ALOG("[AppShellDelegate applicationDidBecomeActive:]");
+}
+
+- (void)applicationWillResignActive:(UIApplication*)application {
+  ALOG("[AppShellDelegate applicationWillResignActive:]");
+}
+
+- (void)applicationDidReceiveMemoryWarning:(UIApplication*)application {
+  ALOG("[AppShellDelegate applicationDidReceiveMemoryWarning:]");
+  NS_NotifyOfMemoryPressure(MemoryPressureState::LowMemory);
+}
+@end
+
+// nsAppShell implementation
+
+NS_IMETHODIMP
+nsAppShell::ResumeNative(void) { return nsBaseAppShell::ResumeNative(); }
+
+nsAppShell::nsAppShell()
+    : mAutoreleasePool(NULL),
+      mDelegate(NULL),
+      mCFRunLoop(NULL),
+      mCFRunLoopSource(NULL),
+      mTerminated(false),
+      mNotifiedWillTerminate(false) {
+  gAppShell = this;
+}
+
+nsAppShell::~nsAppShell() {
+  if (mAutoreleasePool) {
+    [mAutoreleasePool release];
+    mAutoreleasePool = NULL;
+  }
+
+  if (mCFRunLoop) {
+    if (mCFRunLoopSource) {
+      ::CFRunLoopRemoveSource(mCFRunLoop, mCFRunLoopSource,
+                              kCFRunLoopCommonModes);
+      ::CFRelease(mCFRunLoopSource);
+    }
+    ::CFRelease(mCFRunLoop);
+  }
+
+  gAppShell = NULL;
+}
+
+// Init
+//
+// public
+nsresult nsAppShell::Init() {
+  mAutoreleasePool = [[NSAutoreleasePool alloc] init];
+
+  // Add a CFRunLoopSource to the main native run loop.  The source is
+  // responsible for interrupting the run loop when Gecko events are ready.
+
+  mCFRunLoop = [[NSRunLoop currentRunLoop] getCFRunLoop];
+  NS_ENSURE_STATE(mCFRunLoop);
+  ::CFRetain(mCFRunLoop);
+
+  CFRunLoopSourceContext context;
+  bzero(&context, sizeof(context));
+  // context.version = 0;
+  context.info = this;
+  context.perform = ProcessGeckoEvents;
+
+  mCFRunLoopSource = ::CFRunLoopSourceCreate(kCFAllocatorDefault, 0, &context);
+  NS_ENSURE_STATE(mCFRunLoopSource);
+
+  ::CFRunLoopAddSource(mCFRunLoop, mCFRunLoopSource, kCFRunLoopCommonModes);
+
+  return nsBaseAppShell::Init();
+}
+
+// ProcessGeckoEvents
+//
+// The "perform" target of mCFRunLoop, called when mCFRunLoopSource is
+// signalled from ScheduleNativeEventCallback.
+//
+// protected static
+void nsAppShell::ProcessGeckoEvents(void* aInfo) {
+  nsAppShell* self = static_cast<nsAppShell*>(aInfo);
+  self->NativeEventCallback();
+  self->Release();
+}
+
+// WillTerminate
+//
+// public
+void nsAppShell::WillTerminate() {
+  mNotifiedWillTerminate = true;
+  if (mTerminated) return;
+  mTerminated = true;
+  // We won't get another chance to process events
+  NS_ProcessPendingEvents(NS_GetCurrentThread());
+
+  // Unless we call nsBaseAppShell::Exit() here, it might not get called
+  // at all.
+  nsBaseAppShell::Exit();
+}
+
+// ScheduleNativeEventCallback
+//
+// protected virtual
+void nsAppShell::ScheduleNativeEventCallback() {
+  if (mTerminated) return;
+
+  NS_ADDREF_THIS();
+
+  // This will invoke ProcessGeckoEvents on the main thread.
+  ::CFRunLoopSourceSignal(mCFRunLoopSource);
+  ::CFRunLoopWakeUp(mCFRunLoop);
+}
+
+// ProcessNextNativeEvent
+//
+// protected virtual
+bool nsAppShell::ProcessNextNativeEvent(bool aMayWait) {
+  if (mTerminated) return false;
+
+  NSString* currentMode = nil;
+  NSDate* waitUntil = nil;
+  if (aMayWait) waitUntil = [NSDate distantFuture];
+  NSRunLoop* currentRunLoop = [NSRunLoop currentRunLoop];
+
+  BOOL eventProcessed = NO;
+  do {
+    currentMode = [currentRunLoop currentMode];
+    if (!currentMode) currentMode = NSDefaultRunLoopMode;
+
+    if (aMayWait)
+      eventProcessed = [currentRunLoop runMode:currentMode
+                                    beforeDate:waitUntil];
+    else
+      [currentRunLoop acceptInputForMode:currentMode beforeDate:waitUntil];
+  } while (eventProcessed && aMayWait);
+
+  return false;
+}
+
+// Run
+//
+// public
+NS_IMETHODIMP
+nsAppShell::Run(void) {
+  ALOG("nsAppShell::Run");
+  char argv[1][4] = {"app"};
+  UIApplicationMain(1, (char**)argv, nil, @"AppShellDelegate");
+  // UIApplicationMain doesn't exit. :-(
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAppShell::Exit(void) {
+  if (mTerminated) return NS_OK;
+
+  mTerminated = true;
+  return nsBaseAppShell::Exit();
+}
diff --git a/widget/uikit/nsLookAndFeel.h b/widget/uikit/nsLookAndFeel.h
new file mode 100644
index 0000000000..7de7e0712b
--- /dev/null
+++ b/widget/uikit/nsLookAndFeel.h
@@ -0,0 +1,39 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsLookAndFeel
+#define __nsLookAndFeel
+
+#include "nsXPLookAndFeel.h"
+
+class nsLookAndFeel final : public nsXPLookAndFeel {
+ public:
+  nsLookAndFeel();
+  virtual ~nsLookAndFeel();
+
+  void NativeInit() final;
+  virtual void RefreshImpl();
+  nsresult NativeGetImpl(IntID aID, int32_t& aResult) override;
+  nsresult NativeGetFloat(FloatID aID, float& aResult) override;
+  nsresult NativeGetColor(ColorID, ColorScheme, nscolor& aResult) override;
+  bool NativeGetFont(FontID aID, nsString& aFontName,
+                     gfxFontStyle& aFontStyle) override;
+  virtual char16_t GetPasswordCharacterImpl() {
+    // unicode value for the bullet character, used for password textfields.
+    return 0x2022;
+  }
+
+  static bool UseOverlayScrollbars() { return true; }
+
+ private:
+  nscolor mColorTextSelectForeground;
+  nscolor mColorDarkText;
+
+  bool mInitialized;
+
+  void EnsureInit();
+};
+
+#endif
diff --git a/widget/uikit/nsLookAndFeel.mm b/widget/uikit/nsLookAndFeel.mm
new file mode 100644
index 0000000000..29eb52a234
--- /dev/null
+++ b/widget/uikit/nsLookAndFeel.mm
@@ -0,0 +1,361 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <UIKit/UIColor.h>
+#import <UIKit/UIInterface.h>
+
+#include "nsLookAndFeel.h"
+
+#include "mozilla/FontPropertyTypes.h"
+#include "nsStyleConsts.h"
+#include "gfxFont.h"
+#include "gfxFontConstants.h"
+
+nsLookAndFeel::nsLookAndFeel() : mInitialized(false) {}
+
+nsLookAndFeel::~nsLookAndFeel() {}
+
+static nscolor GetColorFromUIColor(UIColor* aColor) {
+  CGColorRef cgColor = [aColor CGColor];
+  CGColorSpaceModel model = CGColorSpaceGetModel(CGColorGetColorSpace(cgColor));
+  const CGFloat* components = CGColorGetComponents(cgColor);
+  if (model == kCGColorSpaceModelRGB) {
+    return NS_RGB((unsigned int)(components[0] * 255.0),
+                  (unsigned int)(components[1] * 255.0),
+                  (unsigned int)(components[2] * 255.0));
+  } else if (model == kCGColorSpaceModelMonochrome) {
+    unsigned int val = (unsigned int)(components[0] * 255.0);
+    return NS_RGBA(val, val, val, (unsigned int)(components[1] * 255.0));
+  }
+  MOZ_ASSERT_UNREACHABLE("Unhandled color space!");
+  return 0;
+}
+
+void nsLookAndFeel::NativeInit() { EnsureInit(); }
+
+void nsLookAndFeel::RefreshImpl() {
+  nsXPLookAndFeel::RefreshImpl();
+
+  mInitialized = false;
+}
+
+nsresult nsLookAndFeel::NativeGetColor(ColorID, ColorScheme, nscolor& aResult) {
+  EnsureInit();
+
+  nsresult res = NS_OK;
+
+  switch (aID) {
+    case ColorID::Highlight:
+      aResult = NS_RGB(0xaa, 0xaa, 0xaa);
+      break;
+    case ColorID::MozMenuhover:
+      aResult = NS_RGB(0xee, 0xee, 0xee);
+      break;
+    case ColorID::Highlighttext:
+    case ColorID::MozMenuhovertext:
+      aResult = mColorTextSelectForeground;
+      break;
+    case ColorID::IMESelectedRawTextBackground:
+    case ColorID::IMESelectedConvertedTextBackground:
+    case ColorID::IMERawInputBackground:
+    case ColorID::IMEConvertedTextBackground:
+      aResult = NS_TRANSPARENT;
+      break;
+    case ColorID::IMESelectedRawTextForeground:
+    case ColorID::IMESelectedConvertedTextForeground:
+    case ColorID::IMERawInputForeground:
+    case ColorID::IMEConvertedTextForeground:
+      aResult = NS_SAME_AS_FOREGROUND_COLOR;
+      break;
+    case ColorID::IMERawInputUnderline:
+    case ColorID::IMEConvertedTextUnderline:
+      aResult = NS_40PERCENT_FOREGROUND_COLOR;
+      break;
+    case ColorID::IMESelectedRawTextUnderline:
+    case ColorID::IMESelectedConvertedTextUnderline:
+      aResult = NS_SAME_AS_FOREGROUND_COLOR;
+      break;
+    case ColorID::SpellCheckerUnderline:
+      aResult = NS_RGB(0xff, 0, 0);
+      break;
+
+    //
+    // css2 system colors http://www.w3.org/TR/REC-CSS2/ui.html#system-colors
+    //
+    case ColorID::Buttontext:
+    case ColorID::MozButtonhovertext:
+    case ColorID::Captiontext:
+    case ColorID::Menutext:
+    case ColorID::Infotext:
+    case ColorID::Windowtext:
+      aResult = mColorDarkText;
+      break;
+    case ColorID::Activecaption:
+      aResult = NS_RGB(0xff, 0xff, 0xff);
+      break;
+    case ColorID::Activeborder:
+      aResult = NS_RGB(0x00, 0x00, 0x00);
+      break;
+    case ColorID::Appworkspace:
+      aResult = NS_RGB(0xFF, 0xFF, 0xFF);
+      break;
+    case ColorID::Background:
+      aResult = NS_RGB(0x63, 0x63, 0xCE);
+      break;
+    case ColorID::Buttonface:
+    case ColorID::MozButtonhoverface:
+      aResult = NS_RGB(0xF0, 0xF0, 0xF0);
+      break;
+    case ColorID::Buttonhighlight:
+      aResult = NS_RGB(0xFF, 0xFF, 0xFF);
+      break;
+    case ColorID::Buttonshadow:
+      aResult = NS_RGB(0xDC, 0xDC, 0xDC);
+      break;
+    case ColorID::Graytext:
+      aResult = NS_RGB(0x44, 0x44, 0x44);
+      break;
+    case ColorID::Inactiveborder:
+      aResult = NS_RGB(0xff, 0xff, 0xff);
+      break;
+    case ColorID::Inactivecaption:
+      aResult = NS_RGB(0xaa, 0xaa, 0xaa);
+      break;
+    case ColorID::Inactivecaptiontext:
+      aResult = NS_RGB(0x45, 0x45, 0x45);
+      break;
+    case ColorID::Scrollbar:
+      aResult = NS_RGB(0, 0, 0);  // XXX
+      break;
+    case ColorID::Threeddarkshadow:
+      aResult = NS_RGB(0xDC, 0xDC, 0xDC);
+      break;
+    case ColorID::Threedshadow:
+      aResult = NS_RGB(0xE0, 0xE0, 0xE0);
+      break;
+    case ColorID::Threedface:
+      aResult = NS_RGB(0xF0, 0xF0, 0xF0);
+      break;
+    case ColorID::Threedhighlight:
+      aResult = NS_RGB(0xff, 0xff, 0xff);
+      break;
+    case ColorID::Threedlightshadow:
+      aResult = NS_RGB(0xDA, 0xDA, 0xDA);
+      break;
+    case ColorID::Menu:
+      aResult = NS_RGB(0xff, 0xff, 0xff);
+      break;
+    case ColorID::Infobackground:
+      aResult = NS_RGB(0xFF, 0xFF, 0xC7);
+      break;
+    case ColorID::Windowframe:
+      aResult = NS_RGB(0xaa, 0xaa, 0xaa);
+      break;
+    case ColorID::Window:
+    case ColorID::MozField:
+    case ColorID::MozCombobox:
+      aResult = NS_RGB(0xff, 0xff, 0xff);
+      break;
+    case ColorID::MozFieldtext:
+    case ColorID::MozComboboxtext:
+      aResult = mColorDarkText;
+      break;
+    case ColorID::MozDialog:
+      aResult = NS_RGB(0xaa, 0xaa, 0xaa);
+      break;
+    case ColorID::MozDialogtext:
+    case ColorID::MozCellhighlighttext:
+    case ColorID::Selecteditemtext:
+    case ColorID::MozColheadertext:
+    case ColorID::MozColheaderhovertext:
+      aResult = mColorDarkText;
+      break;
+    case ColorID::MozMacFocusring:
+      aResult = NS_RGB(0x3F, 0x98, 0xDD);
+      break;
+    case ColorID::MozMacMenutextdisable:
+      aResult = NS_RGB(0x88, 0x88, 0x88);
+      break;
+    case ColorID::MozMacMenutextselect:
+      aResult = NS_RGB(0xaa, 0xaa, 0xaa);
+      break;
+    case ColorID::MozMacDisabledtoolbartext:
+      aResult = NS_RGB(0x3F, 0x3F, 0x3F);
+      break;
+    case ColorID::MozCellhighlight:
+    case ColorID::Selecteditem:
+      // For inactive list selection
+      aResult = NS_RGB(0xaa, 0xaa, 0xaa);
+      break;
+    case ColorID::MozEventreerow:
+      // Background color of even list rows.
+      aResult = NS_RGB(0xff, 0xff, 0xff);
+      break;
+    case ColorID::MozOddtreerow:
+      // Background color of odd list rows.
+      aResult = NS_TRANSPARENT;
+      break;
+    case ColorID::MozNativehyperlinktext:
+      // There appears to be no available system defined color. HARDCODING to
+      // the appropriate color.
+      aResult = NS_RGB(0x14, 0x4F, 0xAE);
+      break;
+    case ColorID::MozNativevisitedhyperlinktext:
+      // Safari defaults to the MacOS color implementation for visited links,
+      // which in turn uses systemPurpleColor, so we do the same here.
+      aResult = GetColorFromUIColor([UIColor systemPurpleColor]);
+      break;
+    default:
+      NS_WARNING("Someone asked nsILookAndFeel for a color I don't know about");
+      aResult = NS_RGB(0xff, 0xff, 0xff);
+      res = NS_ERROR_FAILURE;
+      break;
+  }
+
+  return res;
+}
+
+NS_IMETHODIMP
+nsLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
+  nsresult res = NS_OK;
+
+  switch (aID) {
+    case IntID::ScrollButtonLeftMouseButtonAction:
+      aResult = 0;
+      break;
+    case IntID::ScrollButtonMiddleMouseButtonAction:
+    case IntID::ScrollButtonRightMouseButtonAction:
+      aResult = 3;
+      break;
+    case IntID::CaretBlinkTime:
+      aResult = 567;
+      break;
+    case IntID::CaretWidth:
+      aResult = 1;
+      break;
+    case IntID::ShowCaretDuringSelection:
+      aResult = 0;
+      break;
+    case IntID::SelectTextfieldsOnKeyFocus:
+      // Select textfield content when focused by kbd
+      // used by nsEventStateManager::sTextfieldSelectModel
+      aResult = 1;
+      break;
+    case IntID::SubmenuDelay:
+      aResult = 200;
+      break;
+    case IntID::MenusCanOverlapOSBar:
+      // xul popups are not allowed to overlap the menubar.
+      aResult = 0;
+      break;
+    case IntID::SkipNavigatingDisabledMenuItem:
+      aResult = 1;
+      break;
+    case IntID::DragThresholdX:
+    case IntID::DragThresholdY:
+      aResult = 4;
+      break;
+    case IntID::ScrollArrowStyle:
+      aResult = eScrollArrow_None;
+      break;
+    case IntID::TreeOpenDelay:
+      aResult = 1000;
+      break;
+    case IntID::TreeCloseDelay:
+      aResult = 1000;
+      break;
+    case IntID::TreeLazyScrollDelay:
+      aResult = 150;
+      break;
+    case IntID::TreeScrollDelay:
+      aResult = 100;
+      break;
+    case IntID::TreeScrollLinesMax:
+      aResult = 3;
+      break;
+    case IntID::TabFocusModel:
+      aResult = 1;  // default to just textboxes
+      break;
+    case IntID::ScrollToClick:
+      aResult = 0;
+      break;
+    case IntID::ChosenMenuItemsShouldBlink:
+      aResult = 1;
+      break;
+    case IntID::IMERawInputUnderlineStyle:
+    case IntID::IMEConvertedTextUnderlineStyle:
+    case IntID::IMESelectedRawTextUnderlineStyle:
+    case IntID::IMESelectedConvertedTextUnderline:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Solid);
+      break;
+    case IntID::SpellCheckerUnderlineStyle:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Dotted);
+      break;
+    case IntID::ContextMenuOffsetVertical:
+    case IntID::ContextMenuOffsetHorizontal:
+      aResult = 2;
+      break;
+    default:
+      aResult = 0;
+      res = NS_ERROR_FAILURE;
+  }
+  return res;
+}
+
+NS_IMETHODIMP
+nsLookAndFeel::NativeGetFloat(FloatID aID, float& aResult) {
+  nsresult res = NS_OK;
+
+  switch (aID) {
+    case FloatID::IMEUnderlineRelativeSize:
+      aResult = 2.0f;
+      break;
+    case FloatID::SpellCheckerUnderlineRelativeSize:
+      aResult = 2.0f;
+      break;
+    default:
+      aResult = -1.0;
+      res = NS_ERROR_FAILURE;
+  }
+
+  return res;
+}
+
+bool nsLookAndFeel::NativeGetFont(FontID aID, nsString& aFontName,
+                                  gfxFontStyle& aFontStyle) {
+  // hack for now
+  if (aID == FontID::Window || aID == FontID::Document) {
+    aFontStyle.style = FontSlantStyle::Normal();
+    aFontStyle.weight = FontWeight::Normal();
+    aFontStyle.stretch = FontStretch::Normal();
+    aFontStyle.size = 14;
+    aFontStyle.systemFont = true;
+
+    aFontName.AssignLiteral("sans-serif");
+    return true;
+  }
+
+  // TODO: implement more here?
+  return false;
+}
+
+void nsLookAndFeel::EnsureInit() {
+  if (mInitialized) {
+    return;
+  }
+  mInitialized = true;
+
+  nscolor color;
+  GetColor(ColorID::TextSelectBackground, color);
+  if (color == 0x000000) {
+    mColorTextSelectForeground = NS_RGB(0xff, 0xff, 0xff);
+  } else {
+    mColorTextSelectForeground = NS_SAME_AS_FOREGROUND_COLOR;
+  }
+
+  mColorDarkText = GetColorFromUIColor([UIColor darkTextColor]);
+
+  RecordTelemetry();
+}
diff --git a/widget/uikit/nsScreenManager.h b/widget/uikit/nsScreenManager.h
new file mode 100644
index 0000000000..0d19728264
--- /dev/null
+++ b/widget/uikit/nsScreenManager.h
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsScreenManager_h_
+#define nsScreenManager_h_
+
+#include "nsBaseScreen.h"
+#include "nsIScreenManager.h"
+#include "nsCOMPtr.h"
+#include "nsRect.h"
+
+@class UIScreen;
+
+class UIKitScreen : public nsBaseScreen {
+ public:
+  explicit UIKitScreen(UIScreen* screen);
+  ~UIKitScreen() {}
+
+  NS_IMETHOD GetId(uint32_t* outId) override {
+    *outId = 0;
+    return NS_OK;
+  }
+
+  NS_IMETHOD GetRect(int32_t* aLeft, int32_t* aTop, int32_t* aWidth,
+                     int32_t* aHeight) override;
+  NS_IMETHOD GetAvailRect(int32_t* aLeft, int32_t* aTop, int32_t* aWidth,
+                          int32_t* aHeight) override;
+  NS_IMETHOD GetRectDisplayPix(int32_t* aLeft, int32_t* aTop, int32_t* aWidth,
+                               int32_t* aHeight) override;
+  NS_IMETHOD GetAvailRectDisplayPix(int32_t* aLeft, int32_t* aTop,
+                                    int32_t* aWidth, int32_t* aHeight) override;
+  NS_IMETHOD GetPixelDepth(int32_t* aPixelDepth) override;
+  NS_IMETHOD GetColorDepth(int32_t* aColorDepth) override;
+  NS_IMETHOD GetContentsScaleFactor(double* aContentsScaleFactor) override;
+  NS_IMETHOD GetDefaultCSSScaleFactor(double* aScaleFactor) override {
+    return GetContentsScaleFactor(aScaleFactor);
+  }
+
+ private:
+  UIScreen* mScreen;
+};
+
+class UIKitScreenManager : public nsIScreenManager {
+ public:
+  UIKitScreenManager();
+
+  NS_DECL_ISUPPORTS
+
+  NS_DECL_NSISCREENMANAGER
+
+  static LayoutDeviceIntRect GetBounds();
+
+ private:
+  virtual ~UIKitScreenManager() {}
+  // TODO: support >1 screen, iPad supports external displays
+  nsCOMPtr<nsIScreen> mScreen;
+};
+
+#endif  // nsScreenManager_h_
diff --git a/widget/uikit/nsScreenManager.mm b/widget/uikit/nsScreenManager.mm
new file mode 100644
index 0000000000..da37a4199d
--- /dev/null
+++ b/widget/uikit/nsScreenManager.mm
@@ -0,0 +1,104 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <UIKit/UIScreen.h>
+
+#include "gfxPoint.h"
+#include "nsScreenManager.h"
+#include "nsAppShell.h"
+
+static LayoutDeviceIntRect gScreenBounds;
+static bool gScreenBoundsSet = false;
+
+UIKitScreen::UIKitScreen(UIScreen* aScreen) { mScreen = [aScreen retain]; }
+
+NS_IMETHODIMP
+UIKitScreen::GetRect(int32_t* outX, int32_t* outY, int32_t* outWidth,
+                     int32_t* outHeight) {
+  return GetRectDisplayPix(outX, outY, outWidth, outHeight);
+}
+
+NS_IMETHODIMP
+UIKitScreen::GetAvailRect(int32_t* outX, int32_t* outY, int32_t* outWidth,
+                          int32_t* outHeight) {
+  return GetAvailRectDisplayPix(outX, outY, outWidth, outHeight);
+}
+
+NS_IMETHODIMP
+UIKitScreen::GetRectDisplayPix(int32_t* outX, int32_t* outY, int32_t* outWidth,
+                               int32_t* outHeight) {
+  nsIntRect rect = UIKitScreenManager::GetBounds();
+  *outX = rect.x;
+  *outY = rect.y;
+  *outWidth = rect.width;
+  *outHeight = rect.height;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+UIKitScreen::GetAvailRectDisplayPix(int32_t* outX, int32_t* outY,
+                                    int32_t* outWidth, int32_t* outHeight) {
+  CGRect rect = [mScreen applicationFrame];
+  CGFloat scale = [mScreen scale];
+
+  *outX = rect.origin.x * scale;
+  *outY = rect.origin.y * scale;
+  *outWidth = rect.size.width * scale;
+  *outHeight = rect.size.height * scale;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+UIKitScreen::GetPixelDepth(int32_t* aPixelDepth) {
+  // Close enough.
+  *aPixelDepth = 24;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+UIKitScreen::GetColorDepth(int32_t* aColorDepth) {
+  return GetPixelDepth(aColorDepth);
+}
+
+NS_IMETHODIMP
+UIKitScreen::GetContentsScaleFactor(double* aContentsScaleFactor) {
+  *aContentsScaleFactor = [mScreen scale];
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS(UIKitScreenManager, nsIScreenManager)
+
+UIKitScreenManager::UIKitScreenManager()
+    : mScreen(new UIKitScreen([UIScreen mainScreen])) {}
+
+LayoutDeviceIntRect UIKitScreenManager::GetBounds() {
+  if (!gScreenBoundsSet) {
+    CGRect rect = [[UIScreen mainScreen] bounds];
+    CGFloat scale = [[UIScreen mainScreen] scale];
+    gScreenBounds.x = rect.origin.x * scale;
+    gScreenBounds.y = rect.origin.y * scale;
+    gScreenBounds.width = rect.size.width * scale;
+    gScreenBounds.height = rect.size.height * scale;
+    gScreenBoundsSet = true;
+  }
+  printf("UIKitScreenManager::GetBounds: %d %d %d %d\n", gScreenBounds.x,
+         gScreenBounds.y, gScreenBounds.width, gScreenBounds.height);
+  return gScreenBounds;
+}
+
+NS_IMETHODIMP
+UIKitScreenManager::GetPrimaryScreen(nsIScreen** outScreen) {
+  NS_IF_ADDREF(*outScreen = mScreen.get());
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+UIKitScreenManager::ScreenForRect(int32_t inLeft, int32_t inTop,
+                                  int32_t inWidth, int32_t inHeight,
+                                  nsIScreen** outScreen) {
+  return GetPrimaryScreen(outScreen);
+}
diff --git a/widget/uikit/nsWidgetFactory.mm b/widget/uikit/nsWidgetFactory.mm
new file mode 100644
index 0000000000..356e5b8cdf
--- /dev/null
+++ b/widget/uikit/nsWidgetFactory.mm
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.h"
+#include "mozilla/ModuleUtils.h"
+
+#include "nsWidgetsCID.h"
+
+#include "nsAppShell.h"
+#include "nsAppShellSingleton.h"
+#include "nsLookAndFeel.h"
+#include "nsScreenManager.h"
+
+NS_GENERIC_FACTORY_CONSTRUCTOR(UIKitScreenManager)
+
+#include "GfxInfo.h"
+namespace mozilla {
+namespace widget {
+// This constructor should really be shared with all platforms.
+NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(GfxInfo, Init)
+}  // namespace widget
+}  // namespace mozilla
+
+NS_DEFINE_NAMED_CID(NS_APPSHELL_CID);
+NS_DEFINE_NAMED_CID(NS_SCREENMANAGER_CID);
+NS_DEFINE_NAMED_CID(NS_GFXINFO_CID);
+
+static const mozilla::Module::CIDEntry kWidgetCIDs[] = {
+    {&kNS_APPSHELL_CID, false, nullptr, nsAppShellConstructor},
+    {&kNS_SCREENMANAGER_CID, false, nullptr, UIKitScreenManagerConstructor},
+    {&kNS_GFXINFO_CID, false, nullptr, mozilla::widget::GfxInfoConstructor},
+    {nullptr}};
+
+static const mozilla::Module::ContractIDEntry kWidgetContracts[] = {
+    {"@mozilla.org/widget/appshell/uikit;1", &kNS_APPSHELL_CID},
+    {"@mozilla.org/gfx/screenmanager;1", &kNS_SCREENMANAGER_CID},
+    {"@mozilla.org/gfx/info;1", &kNS_GFXINFO_CID},
+    {nullptr}};
+
+static void nsWidgetUIKitModuleDtor() {
+  nsLookAndFeel::Shutdown();
+  nsAppShellShutdown();
+}
+
+extern const mozilla::Module kWidgetModule = {mozilla::Module::kVersion,
+                                              kWidgetCIDs,
+                                              kWidgetContracts,
+                                              nullptr,
+                                              nullptr,
+                                              nsAppShellInit,
+                                              nsWidgetUIKitModuleDtor};
diff --git a/widget/uikit/nsWindow.h b/widget/uikit/nsWindow.h
new file mode 100644
index 0000000000..5dad452930
--- /dev/null
+++ b/widget/uikit/nsWindow.h
@@ -0,0 +1,116 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NSWINDOW_H_
+#define NSWINDOW_H_
+
+#include "nsBaseWidget.h"
+#include "gfxPoint.h"
+
+#include "nsTArray.h"
+
+@class UIWindow;
+@class UIView;
+@class ChildView;
+
+class nsWindow final : public nsBaseWidget {
+  typedef nsBaseWidget Inherited;
+
+ public:
+  nsWindow();
+
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(nsWindow, Inherited)
+
+  //
+  // nsIWidget
+  //
+
+  [[nodiscard]] virtual nsresult Create(
+      nsIWidget* aParent, nsNativeWidget aNativeParent,
+      const LayoutDeviceIntRect& aRect,
+      widget::InitData* aInitData = nullptr) override;
+  virtual void Destroy() override;
+  virtual void Show(bool aState) override;
+  virtual void Enable(bool aState) override {}
+  virtual bool IsEnabled() const override { return true; }
+  virtual bool IsVisible() const override { return mVisible; }
+  virtual void SetFocus(Raise, mozilla::dom::CallerType aCallerType) override;
+  virtual LayoutDeviceIntPoint WidgetToScreenOffset() override;
+
+  virtual void SetBackgroundColor(const nscolor& aColor) override;
+  virtual void* GetNativeData(uint32_t aDataType) override;
+
+  virtual void Move(double aX, double aY) override;
+  virtual nsSizeMode SizeMode() override { return mSizeMode; }
+  virtual void SetSizeMode(nsSizeMode aMode) override;
+  void EnteredFullScreen(bool aFullScreen);
+  virtual void Resize(double aWidth, double aHeight, bool aRepaint) override;
+  virtual void Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) override;
+  virtual LayoutDeviceIntRect GetScreenBounds() override;
+  void ReportMoveEvent();
+  void ReportSizeEvent();
+  void ReportSizeModeEvent(nsSizeMode aMode);
+
+  CGFloat BackingScaleFactor();
+  void BackingScaleFactorChanged();
+  virtual float GetDPI() override {
+    // XXX: terrible
+    return 326.0f;
+  }
+  virtual double GetDefaultScaleInternal() override {
+    return BackingScaleFactor();
+  }
+  virtual int32_t RoundsWidgetCoordinatesTo() override;
+
+  virtual nsresult SetTitle(const nsAString& aTitle) override { return NS_OK; }
+
+  virtual void Invalidate(const LayoutDeviceIntRect& aRect) override;
+  virtual nsresult DispatchEvent(mozilla::WidgetGUIEvent* aEvent,
+                                 nsEventStatus& aStatus) override;
+
+  void WillPaintWindow();
+  bool PaintWindow(LayoutDeviceIntRegion aRegion);
+
+  bool HasModalDescendents() { return false; }
+
+  // virtual nsresult
+  // NotifyIME(const IMENotification& aIMENotification) override;
+  virtual void SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction);
+  virtual InputContext GetInputContext();
+  /*
+  virtual bool ExecuteNativeKeyBinding(
+                      NativeKeyBindingsType aType,
+                      const mozilla::WidgetKeyboardEvent& aEvent,
+                      DoCommandCallback aCallback,
+                      void* aCallbackData) override;
+  */
+
+ protected:
+  virtual ~nsWindow();
+  void BringToFront();
+  nsWindow* FindTopLevel();
+  bool IsTopLevel();
+  nsresult GetCurrentOffset(uint32_t& aOffset, uint32_t& aLength);
+  nsresult DeleteRange(int aOffset, int aLen);
+
+  void TearDownView();
+
+  ChildView* mNativeView;
+  bool mVisible;
+  nsSizeMode mSizeMode;
+  nsTArray<nsWindow*> mChildren;
+  nsWindow* mParent;
+  InputContext mInputContext;
+
+  void OnSizeChanged(const mozilla::gfx::IntSize& aSize);
+
+  static void DumpWindows();
+  static void DumpWindows(const nsTArray<nsWindow*>& wins, int indent = 0);
+  static void LogWindow(nsWindow* win, int index, int indent);
+};
+
+#endif /* NSWINDOW_H_ */
diff --git a/widget/uikit/nsWindow.mm b/widget/uikit/nsWindow.mm
new file mode 100644
index 0000000000..0c1a38c27c
--- /dev/null
+++ b/widget/uikit/nsWindow.mm
@@ -0,0 +1,767 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#import <UIKit/UIEvent.h>
+#import <UIKit/UIGraphics.h>
+#import <UIKit/UIInterface.h>
+#import <UIKit/UIScreen.h>
+#import <UIKit/UITapGestureRecognizer.h>
+#import <UIKit/UITouch.h>
+#import <UIKit/UIView.h>
+#import <UIKit/UIViewController.h>
+#import <UIKit/UIWindow.h>
+#import <QuartzCore/QuartzCore.h>
+
+#include <algorithm>
+
+#include "nsWindow.h"
+#include "nsScreenManager.h"
+#include "nsAppShell.h"
+
+#include "nsWidgetsCID.h"
+#include "nsGfxCIID.h"
+
+#include "gfxQuartzSurface.h"
+#include "gfxUtils.h"
+#include "gfxImageSurface.h"
+#include "gfxContext.h"
+#include "nsRegion.h"
+#include "Layers.h"
+#include "nsTArray.h"
+
+#include "mozilla/BasicEvents.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/TouchEvents.h"
+#include "mozilla/Unused.h"
+#include "mozilla/dom/MouseEventBinding.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::layers;
+
+#define ALOG(args...)    \
+  fprintf(stderr, args); \
+  fprintf(stderr, "\n")
+
+static LayoutDeviceIntPoint UIKitPointsToDevPixels(CGPoint aPoint,
+                                                   CGFloat aBackingScale) {
+  return LayoutDeviceIntPoint(NSToIntRound(aPoint.x * aBackingScale),
+                              NSToIntRound(aPoint.y * aBackingScale));
+}
+
+static CGRect DevPixelsToUIKitPoints(const LayoutDeviceIntRect& aRect,
+                                     CGFloat aBackingScale) {
+  return CGRectMake((CGFloat)aRect.x / aBackingScale,
+                    (CGFloat)aRect.y / aBackingScale,
+                    (CGFloat)aRect.width / aBackingScale,
+                    (CGFloat)aRect.height / aBackingScale);
+}
+
+// Used to retain a Cocoa object for the remainder of a method's execution.
+class nsAutoRetainUIKitObject {
+ public:
+  nsAutoRetainUIKitObject(id anObject) { mObject = [anObject retain]; }
+  ~nsAutoRetainUIKitObject() { [mObject release]; }
+
+ private:
+  id mObject;  // [STRONG]
+};
+
+@interface ChildView : UIView {
+ @public
+  nsWindow* mGeckoChild;  // weak ref
+  BOOL mWaitingForPaint;
+  CFMutableDictionaryRef mTouches;
+  int mNextTouchID;
+}
+// sets up our view, attaching it to its owning gecko view
+- (id)initWithFrame:(CGRect)inFrame geckoChild:(nsWindow*)inChild;
+// Our Gecko child was Destroy()ed
+- (void)widgetDestroyed;
+// Tear down this ChildView
+- (void)delayedTearDown;
+- (void)sendMouseEvent:(EventMessage)aType
+                 point:(LayoutDeviceIntPoint)aPoint
+                widget:(nsWindow*)aWindow;
+- (void)handleTap:(UITapGestureRecognizer*)sender;
+- (BOOL)isUsingMainThreadOpenGL;
+- (void)drawUsingOpenGL;
+- (void)drawUsingOpenGLCallback;
+- (void)sendTouchEvent:(EventMessage)aType
+               touches:(NSSet*)aTouches
+                widget:(nsWindow*)aWindow;
+// Event handling (UIResponder)
+- (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event;
+- (void)touchesCancelled:(NSSet*)touches withEvent:(UIEvent*)event;
+- (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event;
+- (void)touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event;
+@end
+
+@implementation ChildView
++ (Class)layerClass {
+  return [CAEAGLLayer class];
+}
+
+- (id)initWithFrame:(CGRect)inFrame geckoChild:(nsWindow*)inChild {
+  self.multipleTouchEnabled = YES;
+  if ((self = [super initWithFrame:inFrame])) {
+    mGeckoChild = inChild;
+  }
+  ALOG("[ChildView[%p] initWithFrame:] (mGeckoChild = %p)", (void*)self,
+       (void*)mGeckoChild);
+  self.opaque = YES;
+  self.alpha = 1.0;
+
+  UITapGestureRecognizer* tapRecognizer =
+      [[UITapGestureRecognizer alloc] initWithTarget:self
+                                              action:@selector(handleTap:)];
+  tapRecognizer.numberOfTapsRequired = 1;
+  [self addGestureRecognizer:tapRecognizer];
+
+  mTouches =
+      CFDictionaryCreateMutable(kCFAllocatorDefault, 0, nullptr, nullptr);
+  mNextTouchID = 0;
+  return self;
+}
+
+- (void)widgetDestroyed {
+  mGeckoChild = nullptr;
+  CFRelease(mTouches);
+}
+
+- (void)delayedTearDown {
+  [self removeFromSuperview];
+  [self release];
+}
+
+- (void)sendMouseEvent:(EventMessage)aType
+                 point:(LayoutDeviceIntPoint)aPoint
+                widget:(nsWindow*)aWindow {
+  WidgetMouseEvent event(true, aType, aWindow, WidgetMouseEvent::eReal,
+                         WidgetMouseEvent::eNormal);
+
+  event.mRefPoint = aPoint;
+  event.mClickCount = 1;
+  event.button = MouseButton::ePrimary;
+  event.mTime = PR_IntervalNow();
+  event.inputSource = MouseEvent_Binding::MOZ_SOURCE_UNKNOWN;
+
+  nsEventStatus status;
+  aWindow->DispatchEvent(&event, status);
+}
+
+- (void)handleTap:(UITapGestureRecognizer*)sender {
+  if (sender.state == UIGestureRecognizerStateEnded) {
+    ALOG("[ChildView[%p] handleTap]", self);
+    LayoutDeviceIntPoint lp = UIKitPointsToDevPixels(
+        [sender locationInView:self], [self contentScaleFactor]);
+    [self sendMouseEvent:eMouseMove point:lp widget:mGeckoChild];
+    [self sendMouseEvent:eMouseDown point:lp widget:mGeckoChild];
+    [self sendMouseEvent:eMouseUp point:lp widget:mGeckoChild];
+  }
+}
+
+- (void)sendTouchEvent:(EventMessage)aType
+               touches:(NSSet*)aTouches
+                widget:(nsWindow*)aWindow {
+  WidgetTouchEvent event(true, aType, aWindow);
+  // XXX: I think nativeEvent.timestamp * 1000 is probably usable here but
+  // I don't care that much right now.
+  event.mTime = PR_IntervalNow();
+  event.mTouches.SetCapacity(aTouches.count);
+  for (UITouch* touch in aTouches) {
+    LayoutDeviceIntPoint loc = UIKitPointsToDevPixels(
+        [touch locationInView:self], [self contentScaleFactor]);
+    LayoutDeviceIntPoint radius =
+        UIKitPointsToDevPixels([touch majorRadius], [touch majorRadius]);
+    void* value;
+    if (!CFDictionaryGetValueIfPresent(mTouches, touch, (const void**)&value)) {
+      // This shouldn't happen.
+      NS_ASSERTION(false, "Got a touch that we didn't know about");
+      continue;
+    }
+    int id = reinterpret_cast<int>(value);
+    RefPtr<Touch> t = new Touch(id, loc, radius, 0.0f, 1.0f);
+    event.mRefPoint = loc;
+    event.mTouches.AppendElement(t);
+  }
+  aWindow->DispatchInputEvent(&event);
+}
+
+- (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
+  ALOG("[ChildView[%p] touchesBegan", self);
+  if (!mGeckoChild) return;
+
+  for (UITouch* touch : touches) {
+    CFDictionaryAddValue(mTouches, touch, (void*)mNextTouchID);
+    mNextTouchID++;
+  }
+  [self sendTouchEvent:eTouchStart
+               touches:[event allTouches]
+                widget:mGeckoChild];
+}
+
+- (void)touchesCancelled:(NSSet*)touches withEvent:(UIEvent*)event {
+  ALOG("[ChildView[%p] touchesCancelled", self);
+  [self sendTouchEvent:eTouchCancel touches:touches widget:mGeckoChild];
+  for (UITouch* touch : touches) {
+    CFDictionaryRemoveValue(mTouches, touch);
+  }
+  if (CFDictionaryGetCount(mTouches) == 0) {
+    mNextTouchID = 0;
+  }
+}
+
+- (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event {
+  ALOG("[ChildView[%p] touchesEnded", self);
+  if (!mGeckoChild) return;
+
+  [self sendTouchEvent:eTouchEnd touches:touches widget:mGeckoChild];
+  for (UITouch* touch : touches) {
+    CFDictionaryRemoveValue(mTouches, touch);
+  }
+  if (CFDictionaryGetCount(mTouches) == 0) {
+    mNextTouchID = 0;
+  }
+}
+
+- (void)touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event {
+  ALOG("[ChildView[%p] touchesMoved", self);
+  if (!mGeckoChild) return;
+
+  [self sendTouchEvent:eTouchMove
+               touches:[event allTouches]
+                widget:mGeckoChild];
+}
+
+- (void)setNeedsDisplayInRect:(CGRect)aRect {
+  if ([self isUsingMainThreadOpenGL]) {
+    // Draw without calling drawRect. This prevent us from
+    // needing to access the normal window buffer surface unnecessarily, so we
+    // waste less time synchronizing the two surfaces.
+    if (!mWaitingForPaint) {
+      mWaitingForPaint = YES;
+      // Use NSRunLoopCommonModes instead of the default NSDefaultRunLoopMode
+      // so that the timer also fires while a native menu is open.
+      [self performSelector:@selector(drawUsingOpenGLCallback)
+                 withObject:nil
+                 afterDelay:0
+                    inModes:[NSArray arrayWithObject:NSRunLoopCommonModes]];
+    }
+  }
+}
+
+- (BOOL)isUsingMainThreadOpenGL {
+  if (!mGeckoChild || ![self window]) return NO;
+
+  return NO;
+}
+
+- (void)drawUsingOpenGL {
+  ALOG("drawUsingOpenGL");
+  AUTO_PROFILER_LABEL("ChildView::drawUsingOpenGL", OTHER);
+
+  if (!mGeckoChild->IsVisible()) return;
+
+  mWaitingForPaint = NO;
+
+  LayoutDeviceIntRect geckoBounds = mGeckoChild->GetBounds();
+  LayoutDeviceIntRegion region(geckoBounds);
+
+  mGeckoChild->PaintWindow(region);
+}
+
+// Called asynchronously after setNeedsDisplay in order to avoid entering the
+// normal drawing machinery.
+- (void)drawUsingOpenGLCallback {
+  if (mWaitingForPaint) {
+    [self drawUsingOpenGL];
+  }
+}
+
+// The display system has told us that a portion of our view is dirty. Tell
+// gecko to paint it
+- (void)drawRect:(CGRect)aRect {
+  CGContextRef cgContext = UIGraphicsGetCurrentContext();
+  [self drawRect:aRect inContext:cgContext];
+}
+
+- (void)drawRect:(CGRect)aRect inContext:(CGContextRef)aContext {
+#ifdef DEBUG_UPDATE
+  LayoutDeviceIntRect geckoBounds = mGeckoChild->GetBounds();
+
+  fprintf(stderr,
+          "---- Update[%p][%p] [%f %f %f %f] cgc: %p\n  gecko bounds: [%d %d "
+          "%d %d]\n",
+          self, mGeckoChild, aRect.origin.x, aRect.origin.y, aRect.size.width,
+          aRect.size.height, aContext, geckoBounds.x, geckoBounds.y,
+          geckoBounds.width, geckoBounds.height);
+
+  CGAffineTransform xform = CGContextGetCTM(aContext);
+  fprintf(stderr, "  xform in: [%f %f %f %f %f %f]\n", xform.a, xform.b,
+          xform.c, xform.d, xform.tx, xform.ty);
+#endif
+
+  if (true) {
+    // For Gecko-initiated repaints in OpenGL mode, drawUsingOpenGL is
+    // directly called from a delayed perform callback - without going through
+    // drawRect.
+    // Paints that come through here are triggered by something that Cocoa
+    // controls, for example by window resizing or window focus changes.
+
+    // Do GL composition and return.
+    [self drawUsingOpenGL];
+    return;
+  }
+  AUTO_PROFILER_LABEL("ChildView::drawRect", OTHER);
+
+  // The CGContext that drawRect supplies us with comes with a transform that
+  // scales one user space unit to one Cocoa point, which can consist of
+  // multiple dev pixels. But Gecko expects its supplied context to be scaled
+  // to device pixels, so we need to reverse the scaling.
+  double scale = mGeckoChild->BackingScaleFactor();
+  CGContextSaveGState(aContext);
+  CGContextScaleCTM(aContext, 1.0 / scale, 1.0 / scale);
+
+  CGSize viewSize = [self bounds].size;
+  gfx::IntSize backingSize(viewSize.width * scale, viewSize.height * scale);
+
+  CGContextSaveGState(aContext);
+
+  LayoutDeviceIntRegion region =
+      LayoutDeviceIntRect(NSToIntRound(aRect.origin.x * scale),
+                          NSToIntRound(aRect.origin.y * scale),
+                          NSToIntRound(aRect.size.width * scale),
+                          NSToIntRound(aRect.size.height * scale));
+
+  // Create Cairo objects.
+  RefPtr<gfxQuartzSurface> targetSurface;
+
+  UniquePtrPtr<gfxContext> targetContext;
+  if (gfxPlatform::GetPlatform()->SupportsAzureContentForType(
+          gfx::BackendType::CAIRO)) {
+    // This is dead code unless you mess with prefs, but keep it around for
+    // debugging.
+    targetSurface = new gfxQuartzSurface(aContext, backingSize);
+    targetSurface->SetAllowUseAsSource(false);
+    RefPtr<gfx::DrawTarget> dt =
+        gfxPlatform::CreateDrawTargetForSurface(targetSurface, backingSize);
+    if (!dt || !dt->IsValid()) {
+      gfxDevCrash(mozilla::gfx::LogReason::InvalidContext)
+          << "Window context problem 2 " << backingSize;
+      return;
+    }
+    targetContext = gfxContext::CreateOrNull(dt);
+  } else {
+    MOZ_ASSERT_UNREACHABLE("COREGRAPHICS is the only supported backend");
+  }
+  MOZ_ASSERT(targetContext);  // already checked for valid draw targets above
+
+  // Set up the clip region.
+  targetContext->NewPath();
+  for (auto iter = region.RectIter(); !iter.Done(); iter.Next()) {
+    const LayoutDeviceIntRect& r = iter.Get();
+    targetContext->Rectangle(gfxRect(r.x, r.y, r.width, r.height));
+  }
+  targetContext->Clip();
+
+  // nsAutoRetainCocoaObject kungFuDeathGrip(self);
+  bool painted = false;
+  targetContext = nullptr;
+  targetSurface = nullptr;
+
+  CGContextRestoreGState(aContext);
+
+  // Undo the scale transform so that from now on the context is in
+  // CocoaPoints again.
+  CGContextRestoreGState(aContext);
+  if (!painted && [self isOpaque]) {
+    // Gecko refused to draw, but we've claimed to be opaque, so we have to
+    // draw something--fill with white.
+    CGContextSetRGBFillColor(aContext, 1, 1, 1, 1);
+    CGContextFillRect(aContext, aRect);
+  }
+
+#ifdef DEBUG_UPDATE
+  fprintf(stderr, "---- update done ----\n");
+
+#  if 0
+  CGContextSetRGBStrokeColor (aContext,
+                            ((((unsigned long)self) & 0xff)) / 255.0,
+                            ((((unsigned long)self) & 0xff00) >> 8) / 255.0,
+                            ((((unsigned long)self) & 0xff0000) >> 16) / 255.0,
+                            0.5);
+#  endif
+  CGContextSetRGBStrokeColor(aContext, 1, 0, 0, 0.8);
+  CGContextSetLineWidth(aContext, 4.0);
+  CGContextStrokeRect(aContext, aRect);
+#endif
+}
+@end
+
+nsWindow::nsWindow()
+    : mNativeView(nullptr),
+      mVisible(false),
+      mSizeMode(nsSizeMode_Normal),
+      mParent(nullptr) {}
+
+nsWindow::~nsWindow() {
+  [mNativeView widgetDestroyed];  // Safe if mNativeView is nil.
+  TearDownView();                 // Safe if called twice.
+}
+
+void nsWindow::TearDownView() {
+  if (!mNativeView) return;
+
+  [mNativeView performSelectorOnMainThread:@selector(delayedTearDown)
+                                withObject:nil
+                             waitUntilDone:false];
+  mNativeView = nil;
+}
+
+bool nsWindow::IsTopLevel() {
+  return mWindowType == WindowType::TopLevel ||
+         mWindowType == WindowType::Dialog ||
+         mWindowType == WindowType::Invisible;
+}
+
+//
+// nsIWidget
+//
+
+nsresult nsWindow::Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                          const LayoutDeviceIntRect& aRect,
+                          widget::InitData* aInitData) {
+  ALOG("nsWindow[%p]::Create %p/%p [%d %d %d %d]", (void*)this, (void*)aParent,
+       (void*)aNativeParent, aRect.x, aRect.y, aRect.width, aRect.height);
+  nsWindow* parent = (nsWindow*)aParent;
+  ChildView* nativeParent = (ChildView*)aNativeParent;
+
+  if (parent == nullptr && nativeParent) parent = nativeParent->mGeckoChild;
+  if (parent && nativeParent == nullptr) nativeParent = parent->mNativeView;
+
+  // for toplevel windows, bounds are fixed to full screen size
+  if (parent == nullptr) {
+    if (nsAppShell::gWindow == nil) {
+      mBounds = UIKitScreenManager::GetBounds();
+    } else {
+      CGRect cgRect = [nsAppShell::gWindow bounds];
+      mBounds.x = cgRect.origin.x;
+      mBounds.y = cgRect.origin.y;
+      mBounds.width = cgRect.size.width;
+      mBounds.height = cgRect.size.height;
+    }
+  } else {
+    mBounds = aRect;
+  }
+
+  ALOG("nsWindow[%p]::Create bounds: %d %d %d %d", (void*)this, mBounds.x,
+       mBounds.y, mBounds.width, mBounds.height);
+
+  // Set defaults which can be overriden from aInitData in BaseCreate
+  mWindowType = WindowType::TopLevel;
+  mBorderStyle = BorderStyle::Default;
+
+  Inherited::BaseCreate(aParent, aInitData);
+
+  NS_ASSERTION(IsTopLevel() || parent,
+               "non top level window doesn't have a parent!");
+
+  mNativeView = [[ChildView alloc]
+      initWithFrame:DevPixelsToUIKitPoints(mBounds, BackingScaleFactor())
+         geckoChild:this];
+  mNativeView.hidden = YES;
+
+  if (parent) {
+    parent->mChildren.AppendElement(this);
+    mParent = parent;
+  }
+
+  if (nativeParent) {
+    [nativeParent addSubview:mNativeView];
+  } else if (nsAppShell::gWindow) {
+    [nsAppShell::gWindow.rootViewController.view addSubview:mNativeView];
+  } else {
+    [nsAppShell::gTopLevelViews addObject:mNativeView];
+  }
+
+  return NS_OK;
+}
+
+void nsWindow::Destroy() {
+  for (uint32_t i = 0; i < mChildren.Length(); ++i) {
+    // why do we still have children?
+    mChildren[i]->SetParent(nullptr);
+  }
+
+  if (mParent) mParent->mChildren.RemoveElement(this);
+
+  [mNativeView widgetDestroyed];
+
+  nsBaseWidget::Destroy();
+
+  // ReportDestroyEvent();
+
+  TearDownView();
+
+  nsBaseWidget::OnDestroy();
+
+  return NS_OK;
+}
+
+void nsWindow::Show(bool aState) {
+  if (aState != mVisible) {
+    mNativeView.hidden = aState ? NO : YES;
+    if (aState) {
+      UIView* parentView = mParent
+                               ? mParent->mNativeView
+                               : nsAppShell::gWindow.rootViewController.view;
+      [parentView bringSubviewToFront:mNativeView];
+      [mNativeView setNeedsDisplay];
+    }
+    mVisible = aState;
+  }
+}
+
+void nsWindow::Move(double aX, double aY) {
+  if (!mNativeView || (mBounds.x == aX && mBounds.y == aY)) return;
+
+  // XXX: handle this
+  // The point we have is in Gecko coordinates (origin top-left). Convert
+  // it to Cocoa ones (origin bottom-left).
+  mBounds.x = aX;
+  mBounds.y = aY;
+
+  mNativeView.frame = DevPixelsToUIKitPoints(mBounds, BackingScaleFactor());
+
+  if (mVisible) [mNativeView setNeedsDisplay];
+
+  ReportMoveEvent();
+}
+
+void nsWindow::Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) {
+  BOOL isMoving = (mBounds.x != aX || mBounds.y != aY);
+  BOOL isResizing = (mBounds.width != aWidth || mBounds.height != aHeight);
+  if (!mNativeView || (!isMoving && !isResizing)) return;
+
+  if (isMoving) {
+    mBounds.x = aX;
+    mBounds.y = aY;
+  }
+  if (isResizing) {
+    mBounds.width = aWidth;
+    mBounds.height = aHeight;
+  }
+
+  [mNativeView setFrame:DevPixelsToUIKitPoints(mBounds, BackingScaleFactor())];
+
+  if (mVisible && aRepaint) [mNativeView setNeedsDisplay];
+
+  if (isMoving) ReportMoveEvent();
+
+  if (isResizing) ReportSizeEvent();
+}
+
+void nsWindow::Resize(double aWidth, double aHeight, bool aRepaint) {
+  if (!mNativeView || (mBounds.width == aWidth && mBounds.height == aHeight))
+    return;
+
+  mBounds.width = aWidth;
+  mBounds.height = aHeight;
+
+  [mNativeView setFrame:DevPixelsToUIKitPoints(mBounds, BackingScaleFactor())];
+
+  if (mVisible && aRepaint) [mNativeView setNeedsDisplay];
+
+  ReportSizeEvent();
+}
+
+void nsWindow::SetSizeMode(nsSizeMode aMode) {
+  if (aMode == static_cast<int32_t>(mSizeMode)) {
+    return;
+  }
+
+  mSizeMode = static_cast<nsSizeMode>(aMode);
+  if (aMode == nsSizeMode_Maximized || aMode == nsSizeMode_Fullscreen) {
+    // Resize to fill screen
+    nsBaseWidget::InfallibleMakeFullScreen(true);
+  }
+  ReportSizeModeEvent(aMode);
+}
+
+void nsWindow::Invalidate(const LayoutDeviceIntRect& aRect) {
+  if (!mNativeView || !mVisible) return;
+
+  MOZ_RELEASE_ASSERT(
+      GetLayerManager()->GetBackendType() != LayersBackend::LAYERS_WR,
+      "Shouldn't need to invalidate with accelerated OMTC layers!");
+
+  [mNativeView setNeedsLayout];
+  [mNativeView setNeedsDisplayInRect:DevPixelsToUIKitPoints(
+                                         mBounds, BackingScaleFactor())];
+}
+
+void nsWindow::SetFocus(Raise) {
+  [[mNativeView window] makeKeyWindow];
+  [mNativeView becomeFirstResponder];
+}
+
+void nsWindow::WillPaintWindow() {
+  if (mWidgetListener) {
+    mWidgetListener->WillPaintWindow(this);
+  }
+}
+
+bool nsWindow::PaintWindow(LayoutDeviceIntRegion aRegion) {
+  if (!mWidgetListener) return false;
+
+  bool returnValue = false;
+  returnValue = mWidgetListener->PaintWindow(this, aRegion);
+
+  if (mWidgetListener) {
+    mWidgetListener->DidPaintWindow();
+  }
+
+  return returnValue;
+}
+
+void nsWindow::ReportMoveEvent() { NotifyWindowMoved(mBounds.x, mBounds.y); }
+
+void nsWindow::ReportSizeModeEvent(nsSizeMode aMode) {
+  if (mWidgetListener) {
+    // This is terrible.
+    nsSizeMode theMode;
+    switch (aMode) {
+      case nsSizeMode_Maximized:
+        theMode = nsSizeMode_Maximized;
+        break;
+      case nsSizeMode_Fullscreen:
+        theMode = nsSizeMode_Fullscreen;
+        break;
+      default:
+        return;
+    }
+    mWidgetListener->SizeModeChanged(theMode);
+  }
+}
+
+void nsWindow::ReportSizeEvent() {
+  if (mWidgetListener) {
+    LayoutDeviceIntRect innerBounds = GetClientBounds();
+    mWidgetListener->WindowResized(this, innerBounds.width, innerBounds.height);
+  }
+}
+
+LayoutDeviceIntRect nsWindow::GetScreenBounds() {
+  return LayoutDeviceIntRect(WidgetToScreenOffset(), mBounds.Size());
+}
+
+LayoutDeviceIntPoint nsWindow::WidgetToScreenOffset() {
+  LayoutDeviceIntPoint offset(0, 0);
+  if (mParent) {
+    offset = mParent->WidgetToScreenOffset();
+  }
+
+  CGPoint temp = [mNativeView convertPoint:temp toView:nil];
+
+  if (!mParent && nsAppShell::gWindow) {
+    // convert to screen coords
+    temp = [nsAppShell::gWindow convertPoint:temp toWindow:nil];
+  }
+
+  offset.x += temp.x;
+  offset.y += temp.y;
+
+  return offset;
+}
+
+nsresult nsWindow::DispatchEvent(mozilla::WidgetGUIEvent* aEvent,
+                                 nsEventStatus& aStatus) {
+  aStatus = nsEventStatus_eIgnore;
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(aEvent->mWidget);
+
+  if (mWidgetListener)
+    aStatus = mWidgetListener->HandleEvent(aEvent, mUseAttachedEvents);
+
+  return NS_OK;
+}
+
+void nsWindow::SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction) {
+  // TODO: actually show VKB
+  mInputContext = aContext;
+}
+
+mozilla::widget::InputContext nsWindow::GetInputContext() {
+  return mInputContext;
+}
+
+void nsWindow::SetBackgroundColor(const nscolor& aColor) {
+  mNativeView.backgroundColor = [UIColor colorWithRed:NS_GET_R(aColor)
+                                                green:NS_GET_G(aColor)
+                                                 blue:NS_GET_B(aColor)
+                                                alpha:NS_GET_A(aColor)];
+}
+
+void* nsWindow::GetNativeData(uint32_t aDataType) {
+  void* retVal = nullptr;
+
+  switch (aDataType) {
+    case NS_NATIVE_WIDGET:
+      retVal = (void*)mNativeView;
+      break;
+
+    case NS_NATIVE_WINDOW:
+      retVal = [mNativeView window];
+      break;
+
+    case NS_NATIVE_GRAPHIC:
+      NS_ERROR("Requesting NS_NATIVE_GRAPHIC on a UIKit child view!");
+      break;
+
+    case NS_NATIVE_OFFSETX:
+      retVal = 0;
+      break;
+
+    case NS_NATIVE_OFFSETY:
+      retVal = 0;
+      break;
+
+    case NS_RAW_NATIVE_IME_CONTEXT:
+      retVal = GetPseudoIMEContext();
+      if (retVal) {
+        break;
+      }
+      retVal = NS_ONLY_ONE_NATIVE_IME_CONTEXT;
+      break;
+  }
+
+  return retVal;
+}
+
+CGFloat nsWindow::BackingScaleFactor() {
+  if (mNativeView) {
+    return [mNativeView contentScaleFactor];
+  }
+  return [UIScreen mainScreen].scale;
+}
+
+int32_t nsWindow::RoundsWidgetCoordinatesTo() {
+  if (BackingScaleFactor() == 2.0) {
+    return 2;
+  }
+  return 1;
+}
+
+already_AddRefed<nsIWidget> nsIWidget::CreateTopLevelWindow() {
+  nsCOMPtr<nsIWidget> window = new nsWindow();
+  return window.forget();
+}
+
+already_AddRefed<nsIWidget> nsIWidget::CreateChildWindow() {
+  nsCOMPtr<nsIWidget> window = new nsWindow();
+  return window.forget();
+}
diff --git a/widget/windows/AudioSession.cpp b/widget/windows/AudioSession.cpp
new file mode 100644
index 0000000000..c14278f56c
--- /dev/null
+++ b/widget/windows/AudioSession.cpp
@@ -0,0 +1,346 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <atomic>
+#include <audiopolicy.h>
+#include <windows.h>
+#include <mmdeviceapi.h>
+
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPtr.h"
+#include "nsIStringBundle.h"
+
+#include "nsCOMPtr.h"
+#include "nsID.h"
+#include "nsServiceManagerUtils.h"
+#include "nsString.h"
+#include "nsThreadUtils.h"
+#include "nsXULAppAPI.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/mscom/AgileReference.h"
+#include "mozilla/mscom/Utils.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/WindowsVersion.h"
+
+namespace mozilla {
+namespace widget {
+
+/*
+ * To take advantage of what Vista+ have to offer with respect to audio,
+ * we need to maintain an audio session.  This class wraps IAudioSessionControl
+ * and implements IAudioSessionEvents (for callbacks from Windows)
+ */
+class AudioSession final : public IAudioSessionEvents {
+ public:
+  AudioSession();
+
+  static AudioSession* GetSingleton();
+
+  // COM IUnknown
+  STDMETHODIMP_(ULONG) AddRef();
+  STDMETHODIMP QueryInterface(REFIID, void**);
+  STDMETHODIMP_(ULONG) Release();
+
+  // IAudioSessionEvents
+  STDMETHODIMP OnChannelVolumeChanged(DWORD aChannelCount,
+                                      float aChannelVolumeArray[],
+                                      DWORD aChangedChannel, LPCGUID aContext);
+  STDMETHODIMP OnDisplayNameChanged(LPCWSTR aDisplayName, LPCGUID aContext);
+  STDMETHODIMP OnGroupingParamChanged(LPCGUID aGroupingParam, LPCGUID aContext);
+  STDMETHODIMP OnIconPathChanged(LPCWSTR aIconPath, LPCGUID aContext);
+  STDMETHODIMP OnSessionDisconnected(AudioSessionDisconnectReason aReason);
+  STDMETHODIMP OnSimpleVolumeChanged(float aVolume, BOOL aMute,
+                                     LPCGUID aContext);
+  STDMETHODIMP OnStateChanged(AudioSessionState aState);
+
+  void Start();
+  void Stop(bool shouldRestart = false);
+
+  nsresult GetSessionData(nsID& aID, nsString& aSessionName,
+                          nsString& aIconPath);
+  nsresult SetSessionData(const nsID& aID, const nsString& aSessionName,
+                          const nsString& aIconPath);
+
+ private:
+  ~AudioSession() = default;
+
+  void StopInternal(const MutexAutoLock& aProofOfLock,
+                    bool shouldRestart = false);
+
+ protected:
+  RefPtr<IAudioSessionControl> mAudioSessionControl;
+  nsString mDisplayName;
+  nsString mIconPath;
+  nsID mSessionGroupingParameter;
+  // Guards the IAudioSessionControl
+  mozilla::Mutex mMutex MOZ_UNANNOTATED;
+
+  ThreadSafeAutoRefCnt mRefCnt;
+  NS_DECL_OWNINGTHREAD
+};
+
+StaticRefPtr<AudioSession> sService;
+
+void StartAudioSession() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(!sService);
+  sService = new AudioSession();
+
+  // Destroy AudioSession only after any background task threads have been
+  // stopped or abandoned.
+  ClearOnShutdown(&sService, ShutdownPhase::XPCOMShutdownFinal);
+
+  NS_DispatchBackgroundTask(
+      NS_NewCancelableRunnableFunction("StartAudioSession", []() -> void {
+        MOZ_ASSERT(AudioSession::GetSingleton(),
+                   "AudioSession should outlive background threads");
+        AudioSession::GetSingleton()->Start();
+      }));
+}
+
+void StopAudioSession() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(sService);
+  NS_DispatchBackgroundTask(
+      NS_NewRunnableFunction("StopAudioSession", []() -> void {
+        MOZ_ASSERT(AudioSession::GetSingleton(),
+                   "AudioSession should outlive background threads");
+        AudioSession::GetSingleton()->Stop();
+      }));
+}
+
+AudioSession* AudioSession::GetSingleton() {
+  MOZ_ASSERT(mscom::IsCurrentThreadMTA());
+  return sService;
+}
+
+// It appears Windows will use us on a background thread ...
+NS_IMPL_ADDREF(AudioSession)
+NS_IMPL_RELEASE(AudioSession)
+
+STDMETHODIMP
+AudioSession::QueryInterface(REFIID iid, void** ppv) {
+  const IID IID_IAudioSessionEvents = __uuidof(IAudioSessionEvents);
+  if ((IID_IUnknown == iid) || (IID_IAudioSessionEvents == iid)) {
+    *ppv = static_cast<IAudioSessionEvents*>(this);
+    AddRef();
+    return S_OK;
+  }
+
+  return E_NOINTERFACE;
+}
+
+AudioSession::AudioSession() : mMutex("AudioSessionControl") {
+  // This func must be run on the main thread as
+  // nsStringBundle is not thread safe otherwise
+  MOZ_ASSERT(NS_IsMainThread());
+
+  MOZ_ASSERT(XRE_IsParentProcess(),
+             "Should only get here in a chrome process!");
+
+  nsCOMPtr<nsIStringBundleService> bundleService =
+      do_GetService(NS_STRINGBUNDLE_CONTRACTID);
+  MOZ_ASSERT(bundleService);
+
+  nsCOMPtr<nsIStringBundle> bundle;
+  bundleService->CreateBundle("chrome://branding/locale/brand.properties",
+                              getter_AddRefs(bundle));
+  MOZ_ASSERT(bundle);
+  bundle->GetStringFromName("brandFullName", mDisplayName);
+
+  wchar_t* buffer;
+  mIconPath.GetMutableData(&buffer, MAX_PATH);
+  ::GetModuleFileNameW(nullptr, buffer, MAX_PATH);
+
+  [[maybe_unused]] nsresult rv =
+      nsID::GenerateUUIDInPlace(mSessionGroupingParameter);
+  MOZ_ASSERT(rv == NS_OK);
+}
+
+// Once we are started Windows will hold a reference to us through our
+// IAudioSessionEvents interface that will keep us alive until the appshell
+// calls Stop.
+void AudioSession::Start() {
+  MOZ_ASSERT(mscom::IsCurrentThreadMTA());
+
+  const CLSID CLSID_MMDeviceEnumerator = __uuidof(MMDeviceEnumerator);
+  const IID IID_IMMDeviceEnumerator = __uuidof(IMMDeviceEnumerator);
+  const IID IID_IAudioSessionManager = __uuidof(IAudioSessionManager);
+
+  MutexAutoLock lock(mMutex);
+  MOZ_ASSERT(!mAudioSessionControl);
+  MOZ_ASSERT(!mDisplayName.IsEmpty() || !mIconPath.IsEmpty(),
+             "Should never happen ...");
+
+  auto scopeExit = MakeScopeExit([&] { StopInternal(lock); });
+
+  RefPtr<IMMDeviceEnumerator> enumerator;
+  HRESULT hr =
+      ::CoCreateInstance(CLSID_MMDeviceEnumerator, nullptr, CLSCTX_ALL,
+                         IID_IMMDeviceEnumerator, getter_AddRefs(enumerator));
+  if (FAILED(hr)) {
+    return;
+  }
+
+  RefPtr<IMMDevice> device;
+  hr = enumerator->GetDefaultAudioEndpoint(
+      EDataFlow::eRender, ERole::eMultimedia, getter_AddRefs(device));
+  if (FAILED(hr)) {
+    return;
+  }
+
+  RefPtr<IAudioSessionManager> manager;
+  hr = device->Activate(IID_IAudioSessionManager, CLSCTX_ALL, nullptr,
+                        getter_AddRefs(manager));
+  if (FAILED(hr)) {
+    return;
+  }
+
+  hr = manager->GetAudioSessionControl(&GUID_NULL, 0,
+                                       getter_AddRefs(mAudioSessionControl));
+
+  if (FAILED(hr) || !mAudioSessionControl) {
+    return;
+  }
+
+  // Increments refcount of 'this'.
+  hr = mAudioSessionControl->RegisterAudioSessionNotification(this);
+  if (FAILED(hr)) {
+    return;
+  }
+
+  hr = mAudioSessionControl->SetGroupingParam(
+      (LPGUID) & (mSessionGroupingParameter), nullptr);
+  if (FAILED(hr)) {
+    return;
+  }
+
+  hr = mAudioSessionControl->SetDisplayName(mDisplayName.get(), nullptr);
+  if (FAILED(hr)) {
+    return;
+  }
+
+  hr = mAudioSessionControl->SetIconPath(mIconPath.get(), nullptr);
+  if (FAILED(hr)) {
+    return;
+  }
+
+  scopeExit.release();
+}
+
+void AudioSession::Stop(bool shouldRestart) {
+  MOZ_ASSERT(mscom::IsCurrentThreadMTA());
+
+  MutexAutoLock lock(mMutex);
+  StopInternal(lock, shouldRestart);
+}
+
+void AudioSession::StopInternal(const MutexAutoLock& aProofOfLock,
+                                bool shouldRestart) {
+  if (!mAudioSessionControl) {
+    return;
+  }
+
+  // Decrement refcount of 'this'
+  mAudioSessionControl->UnregisterAudioSessionNotification(this);
+
+  // Deleting the IAudioSessionControl COM object requires the STA/main thread.
+  // Audio code may concurrently be running on the main thread and it may
+  // block waiting for this to complete, creating deadlock.  So we destroy the
+  // IAudioSessionControl on the main thread instead.  In order to do that, we
+  // need to marshall the object to the main thread's apartment with an
+  // AgileReference.
+  mscom::AgileReference agileAsc(mAudioSessionControl);
+  mAudioSessionControl = nullptr;
+  NS_DispatchToMainThread(NS_NewRunnableFunction(
+      "FreeAudioSession",
+      [agileAsc = std::move(agileAsc), shouldRestart]() mutable {
+        // Now release the AgileReference which holds our only reference to the
+        // IAudioSessionControl, then maybe restart.
+        agileAsc = nullptr;
+        if (shouldRestart) {
+          NS_DispatchBackgroundTask(
+              NS_NewCancelableRunnableFunction("RestartAudioSession", [] {
+                AudioSession* as = AudioSession::GetSingleton();
+                MOZ_ASSERT(as);
+                as->Start();
+              }));
+        }
+      }));
+}
+
+void CopynsID(nsID& lhs, const nsID& rhs) {
+  lhs.m0 = rhs.m0;
+  lhs.m1 = rhs.m1;
+  lhs.m2 = rhs.m2;
+  for (int i = 0; i < 8; i++) {
+    lhs.m3[i] = rhs.m3[i];
+  }
+}
+
+nsresult AudioSession::GetSessionData(nsID& aID, nsString& aSessionName,
+                                      nsString& aIconPath) {
+  CopynsID(aID, mSessionGroupingParameter);
+  aSessionName = mDisplayName;
+  aIconPath = mIconPath;
+
+  return NS_OK;
+}
+
+nsresult AudioSession::SetSessionData(const nsID& aID,
+                                      const nsString& aSessionName,
+                                      const nsString& aIconPath) {
+  MOZ_ASSERT(!XRE_IsParentProcess(),
+             "Should never get here in a chrome process!");
+  CopynsID(mSessionGroupingParameter, aID);
+  mDisplayName = aSessionName;
+  mIconPath = aIconPath;
+  return NS_OK;
+}
+
+STDMETHODIMP
+AudioSession::OnChannelVolumeChanged(DWORD aChannelCount,
+                                     float aChannelVolumeArray[],
+                                     DWORD aChangedChannel, LPCGUID aContext) {
+  return S_OK;  // NOOP
+}
+
+STDMETHODIMP
+AudioSession::OnDisplayNameChanged(LPCWSTR aDisplayName, LPCGUID aContext) {
+  return S_OK;  // NOOP
+}
+
+STDMETHODIMP
+AudioSession::OnGroupingParamChanged(LPCGUID aGroupingParam, LPCGUID aContext) {
+  return S_OK;  // NOOP
+}
+
+STDMETHODIMP
+AudioSession::OnIconPathChanged(LPCWSTR aIconPath, LPCGUID aContext) {
+  return S_OK;  // NOOP
+}
+
+STDMETHODIMP
+AudioSession::OnSessionDisconnected(AudioSessionDisconnectReason aReason) {
+  Stop(true /* shouldRestart */);
+  return S_OK;
+}
+
+STDMETHODIMP
+AudioSession::OnSimpleVolumeChanged(float aVolume, BOOL aMute,
+                                    LPCGUID aContext) {
+  return S_OK;  // NOOP
+}
+
+STDMETHODIMP
+AudioSession::OnStateChanged(AudioSessionState aState) {
+  return S_OK;  // NOOP
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/AudioSession.h b/widget/windows/AudioSession.h
new file mode 100644
index 0000000000..612a5e209b
--- /dev/null
+++ b/widget/windows/AudioSession.h
@@ -0,0 +1,19 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsString.h"
+
+namespace mozilla {
+namespace widget {
+
+// Start the audio session in the current process
+void StartAudioSession();
+
+// Stop the audio session in the current process
+void StopAudioSession();
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/CheckInvariantWrapper.h b/widget/windows/CheckInvariantWrapper.h
new file mode 100644
index 0000000000..da6024ec21
--- /dev/null
+++ b/widget/windows/CheckInvariantWrapper.h
@@ -0,0 +1,78 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// A wrapper that uses RAII to ensure that a class invariant is checked
+// before and after any public function is called
+
+#ifndef CHECKINVARIANTWRAPPER_H_
+#define CHECKINVARIANTWRAPPER_H_
+
+#include "mozilla/Attributes.h"
+#include <utility>
+
+namespace mozilla {
+
+//
+// Wraps an object of type T and allows access to its public API by
+// deferencing it using the pointer syntax "->".
+//
+// Using that operator will return a temporary RAII object that
+// calls a method named "CheckInvariant" in its constructor, calls the
+// requested method, and then calls "CheckInvariant" again in its
+// destructor.
+//
+// The only thing your class requires is a method with the following signature:
+//
+// void CheckInvariant() const;
+//
+template <typename T>
+class CheckInvariantWrapper {
+ public:
+  class Wrapper {
+   public:
+    explicit Wrapper(T& aObject) : mObject(aObject) {
+      mObject.CheckInvariant();
+    }
+    ~Wrapper() { mObject.CheckInvariant(); }
+
+    T* operator->() { return &mObject; }
+
+   private:
+    T& mObject;
+  };
+
+  class ConstWrapper {
+   public:
+    explicit ConstWrapper(const T& aObject) : mObject(aObject) {
+      mObject.CheckInvariant();
+    }
+    ~ConstWrapper() { mObject.CheckInvariant(); }
+
+    const T* operator->() const { return &mObject; }
+
+   private:
+    const T& mObject;
+  };
+
+  CheckInvariantWrapper() = default;
+
+  MOZ_IMPLICIT CheckInvariantWrapper(T aObject) : mObject(std::move(aObject)) {}
+
+  template <typename... Args>
+  explicit CheckInvariantWrapper(std::in_place_t, Args&&... args)
+      : mObject(std::forward<Args>(args)...) {}
+
+  const ConstWrapper operator->() const { return ConstWrapper(mObject); }
+
+  Wrapper operator->() { return Wrapper(mObject); }
+
+ private:
+  T mObject;
+};
+
+}  // namespace mozilla
+
+#endif  // CHECKINVARIANTWRAPPER_H_
diff --git a/widget/windows/CompositorWidgetChild.cpp b/widget/windows/CompositorWidgetChild.cpp
new file mode 100644
index 0000000000..b294efef51
--- /dev/null
+++ b/widget/windows/CompositorWidgetChild.cpp
@@ -0,0 +1,114 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CompositorWidgetChild.h"
+#include "mozilla/Unused.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/widget/CompositorWidgetVsyncObserver.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "nsBaseWidget.h"
+#include "VsyncDispatcher.h"
+#include "gfxPlatform.h"
+#include "RemoteBackbuffer.h"
+
+namespace mozilla {
+namespace widget {
+
+CompositorWidgetChild::CompositorWidgetChild(
+    RefPtr<CompositorVsyncDispatcher> aVsyncDispatcher,
+    RefPtr<CompositorWidgetVsyncObserver> aVsyncObserver,
+    const CompositorWidgetInitData& aInitData)
+    : mVsyncDispatcher(aVsyncDispatcher),
+      mVsyncObserver(aVsyncObserver),
+      mCompositorWnd(nullptr),
+      mWnd(reinterpret_cast<HWND>(
+          aInitData.get_WinCompositorWidgetInitData().hWnd())),
+      mTransparencyMode(
+          aInitData.get_WinCompositorWidgetInitData().transparencyMode()),
+      mRemoteBackbufferProvider() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  MOZ_ASSERT(!gfxPlatform::IsHeadless());
+  MOZ_ASSERT(mWnd && ::IsWindow(mWnd));
+}
+
+CompositorWidgetChild::~CompositorWidgetChild() {}
+
+bool CompositorWidgetChild::Initialize() {
+  mRemoteBackbufferProvider = std::make_unique<remote_backbuffer::Provider>();
+  if (!mRemoteBackbufferProvider->Initialize(mWnd, OtherPid(),
+                                             mTransparencyMode)) {
+    return false;
+  }
+
+  auto maybeRemoteHandles = mRemoteBackbufferProvider->CreateRemoteHandles();
+  if (!maybeRemoteHandles) {
+    return false;
+  }
+
+  Unused << SendInitialize(*maybeRemoteHandles);
+
+  return true;
+}
+
+void CompositorWidgetChild::EnterPresentLock() {
+  Unused << SendEnterPresentLock();
+}
+
+void CompositorWidgetChild::LeavePresentLock() {
+  Unused << SendLeavePresentLock();
+}
+
+void CompositorWidgetChild::OnDestroyWindow() {}
+
+bool CompositorWidgetChild::OnWindowResize(const LayoutDeviceIntSize& aSize) {
+  return true;
+}
+
+void CompositorWidgetChild::OnWindowModeChange(nsSizeMode aSizeMode) {}
+
+void CompositorWidgetChild::UpdateTransparency(TransparencyMode aMode) {
+  mTransparencyMode = aMode;
+  mRemoteBackbufferProvider->UpdateTransparencyMode(aMode);
+  Unused << SendUpdateTransparency(aMode);
+}
+
+void CompositorWidgetChild::NotifyVisibilityUpdated(nsSizeMode aSizeMode,
+                                                    bool aIsFullyOccluded) {
+  Unused << SendNotifyVisibilityUpdated(aSizeMode, aIsFullyOccluded);
+};
+
+void CompositorWidgetChild::ClearTransparentWindow() {
+  Unused << SendClearTransparentWindow();
+}
+
+mozilla::ipc::IPCResult CompositorWidgetChild::RecvObserveVsync() {
+  mVsyncDispatcher->SetCompositorVsyncObserver(mVsyncObserver);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult CompositorWidgetChild::RecvUnobserveVsync() {
+  mVsyncDispatcher->SetCompositorVsyncObserver(nullptr);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult CompositorWidgetChild::RecvUpdateCompositorWnd(
+    const WindowsHandle& aCompositorWnd, const WindowsHandle& aParentWnd,
+    UpdateCompositorWndResolver&& aResolve) {
+  HWND parentWnd = reinterpret_cast<HWND>(aParentWnd);
+  if (mWnd == parentWnd) {
+    mCompositorWnd = reinterpret_cast<HWND>(aCompositorWnd);
+    ::SetParent(mCompositorWnd, mWnd);
+    aResolve(true);
+  } else {
+    aResolve(false);
+    gfxCriticalNote << "Parent winow does not match";
+    MOZ_ASSERT_UNREACHABLE("unexpected to happen");
+  }
+
+  return IPC_OK();
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/CompositorWidgetChild.h b/widget/windows/CompositorWidgetChild.h
new file mode 100644
index 0000000000..bec8ead98e
--- /dev/null
+++ b/widget/windows/CompositorWidgetChild.h
@@ -0,0 +1,62 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_CompositorWidgetChild_h
+#define widget_windows_CompositorWidgetChild_h
+
+#include "WinCompositorWidget.h"
+#include "mozilla/widget/PCompositorWidgetChild.h"
+#include "mozilla/widget/CompositorWidgetVsyncObserver.h"
+
+namespace mozilla {
+class CompositorVsyncDispatcher;
+
+namespace widget {
+
+namespace remote_backbuffer {
+class Provider;
+}
+
+class CompositorWidgetChild final : public PCompositorWidgetChild,
+                                    public PlatformCompositorWidgetDelegate {
+ public:
+  CompositorWidgetChild(RefPtr<CompositorVsyncDispatcher> aVsyncDispatcher,
+                        RefPtr<CompositorWidgetVsyncObserver> aVsyncObserver,
+                        const CompositorWidgetInitData& aInitData);
+  ~CompositorWidgetChild() override;
+
+  bool Initialize();
+
+  void EnterPresentLock() override;
+  void LeavePresentLock() override;
+  void OnDestroyWindow() override;
+  bool OnWindowResize(const LayoutDeviceIntSize& aSize) override;
+  void OnWindowModeChange(nsSizeMode aSizeMode) override;
+  void UpdateTransparency(TransparencyMode aMode) override;
+  void NotifyVisibilityUpdated(nsSizeMode aSizeMode,
+                               bool aIsFullyOccluded) override;
+  void ClearTransparentWindow() override;
+
+  mozilla::ipc::IPCResult RecvObserveVsync() override;
+  mozilla::ipc::IPCResult RecvUnobserveVsync() override;
+  mozilla::ipc::IPCResult RecvUpdateCompositorWnd(
+      const WindowsHandle& aCompositorWnd, const WindowsHandle& aParentWnd,
+      UpdateCompositorWndResolver&& aResolve) override;
+
+ private:
+  RefPtr<CompositorVsyncDispatcher> mVsyncDispatcher;
+  RefPtr<CompositorWidgetVsyncObserver> mVsyncObserver;
+  HWND mCompositorWnd;
+
+  HWND mWnd;
+  TransparencyMode mTransparencyMode;
+
+  std::unique_ptr<remote_backbuffer::Provider> mRemoteBackbufferProvider;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_windows_CompositorWidgetChild_h
diff --git a/widget/windows/CompositorWidgetParent.cpp b/widget/windows/CompositorWidgetParent.cpp
new file mode 100644
index 0000000000..b25d30d9d5
--- /dev/null
+++ b/widget/windows/CompositorWidgetParent.cpp
@@ -0,0 +1,232 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "CompositorWidgetParent.h"
+
+#include "mozilla/Unused.h"
+#include "mozilla/StaticPrefs_layers.h"
+#include "mozilla/gfx/DeviceManagerDx.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/layers/Compositor.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+#include "mozilla/layers/CompositorThread.h"
+#include "mozilla/webrender/RenderThread.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "nsWindow.h"
+#include "VsyncDispatcher.h"
+#include "WinCompositorWindowThread.h"
+#include "VRShMem.h"
+#include "RemoteBackbuffer.h"
+
+#include <ddraw.h>
+
+namespace mozilla {
+namespace widget {
+
+using namespace mozilla::gfx;
+using namespace mozilla;
+
+CompositorWidgetParent::CompositorWidgetParent(
+    const CompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions)
+    : WinCompositorWidget(aInitData.get_WinCompositorWidgetInitData(),
+                          aOptions),
+      mWnd(reinterpret_cast<HWND>(
+          aInitData.get_WinCompositorWidgetInitData().hWnd())),
+      mTransparencyMode(uint32_t(
+          aInitData.get_WinCompositorWidgetInitData().transparencyMode())),
+      mSizeMode(nsSizeMode_Normal),
+      mIsFullyOccluded(false),
+      mRemoteBackbufferClient() {
+  MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_GPU);
+  MOZ_ASSERT(mWnd && ::IsWindow(mWnd));
+}
+
+CompositorWidgetParent::~CompositorWidgetParent() {}
+
+bool CompositorWidgetParent::Initialize(
+    const RemoteBackbufferHandles& aRemoteHandles) {
+  mRemoteBackbufferClient = std::make_unique<remote_backbuffer::Client>();
+  if (!mRemoteBackbufferClient->Initialize(aRemoteHandles)) {
+    return false;
+  }
+
+  return true;
+}
+
+bool CompositorWidgetParent::PreRender(WidgetRenderingContext* aContext) {
+  // This can block waiting for WM_SETTEXT to finish
+  // Using PreRender is unnecessarily pessimistic because
+  // we technically only need to block during the present call
+  // not all of compositor rendering
+  mPresentLock.Enter();
+  return true;
+}
+
+void CompositorWidgetParent::PostRender(WidgetRenderingContext* aContext) {
+  mPresentLock.Leave();
+}
+
+LayoutDeviceIntSize CompositorWidgetParent::GetClientSize() {
+  RECT r;
+  if (!::GetClientRect(mWnd, &r)) {
+    return LayoutDeviceIntSize();
+  }
+  return LayoutDeviceIntSize(r.right - r.left, r.bottom - r.top);
+}
+
+already_AddRefed<gfx::DrawTarget>
+CompositorWidgetParent::StartRemoteDrawingInRegion(
+    const LayoutDeviceIntRegion& aInvalidRegion,
+    layers::BufferMode* aBufferMode) {
+  MOZ_ASSERT(mRemoteBackbufferClient);
+  MOZ_ASSERT(aBufferMode);
+
+  // Because we use remote backbuffering, there is no need to use a local
+  // backbuffer too.
+  (*aBufferMode) = layers::BufferMode::BUFFER_NONE;
+
+  return mRemoteBackbufferClient->BorrowDrawTarget();
+}
+
+void CompositorWidgetParent::EndRemoteDrawingInRegion(
+    gfx::DrawTarget* aDrawTarget, const LayoutDeviceIntRegion& aInvalidRegion) {
+  Unused << mRemoteBackbufferClient->PresentDrawTarget(
+      aInvalidRegion.ToUnknownRegion());
+}
+
+bool CompositorWidgetParent::NeedsToDeferEndRemoteDrawing() { return false; }
+
+already_AddRefed<gfx::DrawTarget>
+CompositorWidgetParent::GetBackBufferDrawTarget(gfx::DrawTarget* aScreenTarget,
+                                                const gfx::IntRect& aRect,
+                                                bool* aOutIsCleared) {
+  MOZ_CRASH(
+      "Unexpected call to GetBackBufferDrawTarget() with remote "
+      "backbuffering in use");
+}
+
+already_AddRefed<gfx::SourceSurface>
+CompositorWidgetParent::EndBackBufferDrawing() {
+  MOZ_CRASH(
+      "Unexpected call to EndBackBufferDrawing() with remote "
+      "backbuffering in use");
+}
+
+bool CompositorWidgetParent::InitCompositor(layers::Compositor* aCompositor) {
+  return true;
+}
+
+bool CompositorWidgetParent::IsHidden() const { return ::IsIconic(mWnd); }
+
+mozilla::ipc::IPCResult CompositorWidgetParent::RecvInitialize(
+    const RemoteBackbufferHandles& aRemoteHandles) {
+  Unused << Initialize(aRemoteHandles);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult CompositorWidgetParent::RecvEnterPresentLock() {
+  mPresentLock.Enter();
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult CompositorWidgetParent::RecvLeavePresentLock() {
+  mPresentLock.Leave();
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult CompositorWidgetParent::RecvUpdateTransparency(
+    const TransparencyMode& aMode) {
+  mTransparencyMode = uint32_t(aMode);
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult CompositorWidgetParent::RecvNotifyVisibilityUpdated(
+    const nsSizeMode& aSizeMode, const bool& aIsFullyOccluded) {
+  mSizeMode = aSizeMode;
+  mIsFullyOccluded = aIsFullyOccluded;
+  return IPC_OK();
+}
+
+nsSizeMode CompositorWidgetParent::CompositorWidgetParent::GetWindowSizeMode()
+    const {
+  nsSizeMode sizeMode = mSizeMode;
+  return sizeMode;
+}
+
+bool CompositorWidgetParent::CompositorWidgetParent::GetWindowIsFullyOccluded()
+    const {
+  bool isFullyOccluded = mIsFullyOccluded;
+  return isFullyOccluded;
+}
+
+mozilla::ipc::IPCResult CompositorWidgetParent::RecvClearTransparentWindow() {
+  gfx::CriticalSectionAutoEnter lock(&mPresentLock);
+
+  RefPtr<DrawTarget> drawTarget = mRemoteBackbufferClient->BorrowDrawTarget();
+  if (!drawTarget) {
+    return IPC_OK();
+  }
+
+  IntSize size = drawTarget->GetSize();
+  if (size.IsEmpty()) {
+    return IPC_OK();
+  }
+
+  drawTarget->ClearRect(Rect(0, 0, size.width, size.height));
+
+  Unused << mRemoteBackbufferClient->PresentDrawTarget(
+      IntRect(0, 0, size.width, size.height));
+
+  return IPC_OK();
+}
+
+nsIWidget* CompositorWidgetParent::RealWidget() { return nullptr; }
+
+void CompositorWidgetParent::ObserveVsync(VsyncObserver* aObserver) {
+  if (aObserver) {
+    Unused << SendObserveVsync();
+  } else {
+    Unused << SendUnobserveVsync();
+  }
+  mVsyncObserver = aObserver;
+}
+
+RefPtr<VsyncObserver> CompositorWidgetParent::GetVsyncObserver() const {
+  MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_GPU);
+  return mVsyncObserver;
+}
+
+void CompositorWidgetParent::UpdateCompositorWnd(const HWND aCompositorWnd,
+                                                 const HWND aParentWnd) {
+  MOZ_ASSERT(layers::CompositorThreadHolder::IsInCompositorThread());
+  MOZ_ASSERT(mRootLayerTreeID.isSome());
+
+  RefPtr<CompositorWidgetParent> self = this;
+  SendUpdateCompositorWnd(reinterpret_cast<WindowsHandle>(aCompositorWnd),
+                          reinterpret_cast<WindowsHandle>(aParentWnd))
+      ->Then(
+          layers::CompositorThread(), __func__,
+          [self](const bool& aSuccess) {
+            if (aSuccess && self->mRootLayerTreeID.isSome() &&
+                layers::CompositorThreadHolder::IsActive()) {
+              self->mSetParentCompleted = true;
+              // Schedule composition after ::SetParent() call in parent
+              // process.
+              layers::CompositorBridgeParent::ScheduleForcedComposition(
+                  self->mRootLayerTreeID.ref(), wr::RenderReasons::WIDGET);
+            }
+          },
+          [self](const mozilla::ipc::ResponseRejectReason&) {});
+}
+
+void CompositorWidgetParent::SetRootLayerTreeID(
+    const layers::LayersId& aRootLayerTreeId) {
+  mRootLayerTreeID = Some(aRootLayerTreeId);
+}
+
+void CompositorWidgetParent::ActorDestroy(ActorDestroyReason aWhy) {}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/CompositorWidgetParent.h b/widget/windows/CompositorWidgetParent.h
new file mode 100644
index 0000000000..0f91fa7ccb
--- /dev/null
+++ b/widget/windows/CompositorWidgetParent.h
@@ -0,0 +1,92 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_CompositorWidgetParent_h
+#define widget_windows_CompositorWidgetParent_h
+
+#include "WinCompositorWidget.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/widget/PCompositorWidgetParent.h"
+
+namespace mozilla {
+namespace widget {
+
+enum class TransparencyMode : uint8_t;
+
+namespace remote_backbuffer {
+class Client;
+}
+
+class CompositorWidgetParent final : public PCompositorWidgetParent,
+                                     public WinCompositorWidget {
+ public:
+  explicit CompositorWidgetParent(const CompositorWidgetInitData& aInitData,
+                                  const layers::CompositorOptions& aOptions);
+  ~CompositorWidgetParent() override;
+
+  bool Initialize(const RemoteBackbufferHandles& aRemoteHandles);
+
+  bool PreRender(WidgetRenderingContext*) override;
+  void PostRender(WidgetRenderingContext*) override;
+  already_AddRefed<gfx::DrawTarget> StartRemoteDrawingInRegion(
+      const LayoutDeviceIntRegion& aInvalidRegion,
+      layers::BufferMode* aBufferMode) override;
+  void EndRemoteDrawingInRegion(
+      gfx::DrawTarget* aDrawTarget,
+      const LayoutDeviceIntRegion& aInvalidRegion) override;
+  bool NeedsToDeferEndRemoteDrawing() override;
+  LayoutDeviceIntSize GetClientSize() override;
+  already_AddRefed<gfx::DrawTarget> GetBackBufferDrawTarget(
+      gfx::DrawTarget* aScreenTarget, const gfx::IntRect& aRect,
+      bool* aOutIsCleared) override;
+  already_AddRefed<gfx::SourceSurface> EndBackBufferDrawing() override;
+  bool InitCompositor(layers::Compositor* aCompositor) override;
+  bool IsHidden() const override;
+
+  nsSizeMode GetWindowSizeMode() const override;
+  bool GetWindowIsFullyOccluded() const override;
+
+  mozilla::ipc::IPCResult RecvInitialize(
+      const RemoteBackbufferHandles& aRemoteHandles) override;
+  mozilla::ipc::IPCResult RecvEnterPresentLock() override;
+  mozilla::ipc::IPCResult RecvLeavePresentLock() override;
+  mozilla::ipc::IPCResult RecvUpdateTransparency(
+      const TransparencyMode& aMode) override;
+  mozilla::ipc::IPCResult RecvNotifyVisibilityUpdated(
+      const nsSizeMode& aSizeMode, const bool& aIsFullyOccluded) override;
+  mozilla::ipc::IPCResult RecvClearTransparentWindow() override;
+  void ActorDestroy(ActorDestroyReason aWhy) override;
+
+  nsIWidget* RealWidget() override;
+  void ObserveVsync(VsyncObserver* aObserver) override;
+  RefPtr<VsyncObserver> GetVsyncObserver() const override;
+
+  // PlatformCompositorWidgetDelegate Overrides
+  void UpdateCompositorWnd(const HWND aCompositorWnd,
+                           const HWND aParentWnd) override;
+  void SetRootLayerTreeID(const layers::LayersId& aRootLayerTreeId) override;
+
+ private:
+  RefPtr<VsyncObserver> mVsyncObserver;
+  Maybe<layers::LayersId> mRootLayerTreeID;
+
+  HWND mWnd;
+
+  gfx::CriticalSection mPresentLock;
+
+  // Transparency handling.
+  mozilla::Atomic<uint32_t, MemoryOrdering::Relaxed> mTransparencyMode;
+
+  // Visibility handling.
+  mozilla::Atomic<nsSizeMode, MemoryOrdering::Relaxed> mSizeMode;
+  mozilla::Atomic<bool, MemoryOrdering::Relaxed> mIsFullyOccluded;
+
+  std::unique_ptr<remote_backbuffer::Client> mRemoteBackbufferClient;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_windows_CompositorWidgetParent_h
diff --git a/widget/windows/DirectManipulationOwner.cpp b/widget/windows/DirectManipulationOwner.cpp
new file mode 100644
index 0000000000..569dd4e189
--- /dev/null
+++ b/widget/windows/DirectManipulationOwner.cpp
@@ -0,0 +1,722 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DirectManipulationOwner.h"
+#include "nsWindow.h"
+#include "WinModifierKeyState.h"
+#include "InputData.h"
+#include "mozilla/StaticPrefs_apz.h"
+#include "mozilla/SwipeTracker.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/VsyncDispatcher.h"
+
+#include "directmanipulation.h"
+
+namespace mozilla {
+namespace widget {
+
+class DManipEventHandler : public IDirectManipulationViewportEventHandler,
+                           public IDirectManipulationInteractionEventHandler {
+ public:
+  typedef mozilla::LayoutDeviceIntRect LayoutDeviceIntRect;
+
+  friend class DirectManipulationOwner;
+
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(DManipEventHandler)
+
+  STDMETHODIMP QueryInterface(REFIID, void**) override;
+
+  friend class DirectManipulationOwner;
+
+  explicit DManipEventHandler(nsWindow* aWindow,
+                              DirectManipulationOwner* aOwner,
+                              const LayoutDeviceIntRect& aBounds);
+
+  HRESULT STDMETHODCALLTYPE OnViewportStatusChanged(
+      IDirectManipulationViewport* viewport, DIRECTMANIPULATION_STATUS current,
+      DIRECTMANIPULATION_STATUS previous) override;
+
+  HRESULT STDMETHODCALLTYPE
+  OnViewportUpdated(IDirectManipulationViewport* viewport) override;
+
+  HRESULT STDMETHODCALLTYPE
+  OnContentUpdated(IDirectManipulationViewport* viewport,
+                   IDirectManipulationContent* content) override;
+
+  HRESULT STDMETHODCALLTYPE
+  OnInteraction(IDirectManipulationViewport2* viewport,
+                DIRECTMANIPULATION_INTERACTION_TYPE interaction) override;
+
+  void Update();
+
+  class VObserver final : public mozilla::VsyncObserver {
+    NS_INLINE_DECL_THREADSAFE_REFCOUNTING(DManipEventHandler::VObserver,
+                                          override)
+
+   public:
+    void NotifyVsync(const mozilla::VsyncEvent& aVsync) override {
+      if (mOwner) {
+        mOwner->Update();
+      }
+    }
+    explicit VObserver(DManipEventHandler* aOwner) : mOwner(aOwner) {}
+
+    void ClearOwner() { mOwner = nullptr; }
+
+   private:
+    virtual ~VObserver() {}
+    DManipEventHandler* mOwner;
+  };
+
+  enum class State { eNone, ePanning, eInertia, ePinching };
+  void TransitionToState(State aNewState);
+
+  enum class Phase { eStart, eMiddle, eEnd };
+  // Return value indicates if we sent an event or not and hence if we should
+  // update mLastScale. (We only want to send pinch events if the computed
+  // deltaY for the corresponding WidgetWheelEvent would be non-zero.)
+  bool SendPinch(Phase aPhase, float aScale);
+  void SendPan(Phase aPhase, float x, float y, bool aIsInertia);
+  static void SendPanCommon(nsWindow* aWindow, Phase aPhase,
+                            ScreenPoint aPosition, double aDeltaX,
+                            double aDeltaY, Modifiers aMods, bool aIsInertia);
+
+  static void SynthesizeNativeTouchpadPan(
+      nsWindow* aWindow, nsIWidget::TouchpadGesturePhase aEventPhase,
+      LayoutDeviceIntPoint aPoint, double aDeltaX, double aDeltaY,
+      int32_t aModifierFlags);
+
+ private:
+  virtual ~DManipEventHandler() = default;
+
+  nsWindow* mWindow;
+  DirectManipulationOwner* mOwner;
+  RefPtr<VObserver> mObserver;
+  float mLastScale;
+  float mLastXOffset;
+  float mLastYOffset;
+  LayoutDeviceIntRect mBounds;
+  bool mShouldSendPanStart;
+  bool mShouldSendPinchStart;
+  State mState = State::eNone;
+};
+
+DManipEventHandler::DManipEventHandler(nsWindow* aWindow,
+                                       DirectManipulationOwner* aOwner,
+                                       const LayoutDeviceIntRect& aBounds)
+    : mWindow(aWindow),
+      mOwner(aOwner),
+      mLastScale(1.f),
+      mLastXOffset(0.f),
+      mLastYOffset(0.f),
+      mBounds(aBounds),
+      mShouldSendPanStart(false),
+      mShouldSendPinchStart(false) {}
+
+STDMETHODIMP
+DManipEventHandler::QueryInterface(REFIID iid, void** ppv) {
+  const IID IID_IDirectManipulationViewportEventHandler =
+      __uuidof(IDirectManipulationViewportEventHandler);
+  const IID IID_IDirectManipulationInteractionEventHandler =
+      __uuidof(IDirectManipulationInteractionEventHandler);
+
+  if ((IID_IUnknown == iid) ||
+      (IID_IDirectManipulationViewportEventHandler == iid)) {
+    *ppv = static_cast<IDirectManipulationViewportEventHandler*>(this);
+    AddRef();
+    return S_OK;
+  }
+  if (IID_IDirectManipulationInteractionEventHandler == iid) {
+    *ppv = static_cast<IDirectManipulationInteractionEventHandler*>(this);
+    AddRef();
+    return S_OK;
+  }
+
+  return E_NOINTERFACE;
+}
+
+HRESULT
+DManipEventHandler::OnViewportStatusChanged(
+    IDirectManipulationViewport* viewport, DIRECTMANIPULATION_STATUS current,
+    DIRECTMANIPULATION_STATUS previous) {
+  if (current == previous) {
+    return S_OK;
+  }
+
+  if (current == DIRECTMANIPULATION_INERTIA) {
+    if (previous != DIRECTMANIPULATION_RUNNING || mState != State::ePanning) {
+      // xxx transition to none?
+      return S_OK;
+    }
+
+    TransitionToState(State::eInertia);
+  }
+
+  if (current == DIRECTMANIPULATION_RUNNING) {
+    // INERTIA -> RUNNING, should start a new sequence.
+    if (previous == DIRECTMANIPULATION_INERTIA) {
+      TransitionToState(State::eNone);
+    }
+  }
+
+  if (current != DIRECTMANIPULATION_ENABLED &&
+      current != DIRECTMANIPULATION_READY) {
+    return S_OK;
+  }
+
+  // A session has ended, reset the transform.
+  if (mLastScale != 1.f || mLastXOffset != 0.f || mLastYOffset != 0.f) {
+    HRESULT hr =
+        viewport->ZoomToRect(0, 0, mBounds.width, mBounds.height, false);
+    if (!SUCCEEDED(hr)) {
+      NS_WARNING("ZoomToRect failed");
+    }
+  }
+  mLastScale = 1.f;
+  mLastXOffset = 0.f;
+  mLastYOffset = 0.f;
+
+  TransitionToState(State::eNone);
+
+  return S_OK;
+}
+
+HRESULT
+DManipEventHandler::OnViewportUpdated(IDirectManipulationViewport* viewport) {
+  return S_OK;
+}
+
+void DManipEventHandler::TransitionToState(State aNewState) {
+  if (mState == aNewState) {
+    return;
+  }
+
+  State prevState = mState;
+  mState = aNewState;
+
+  // End the previous sequence.
+  switch (prevState) {
+    case State::ePanning: {
+      // ePanning -> *: PanEnd
+      SendPan(Phase::eEnd, 0.f, 0.f, false);
+      break;
+    }
+    case State::eInertia: {
+      // eInertia -> *: MomentumEnd
+      SendPan(Phase::eEnd, 0.f, 0.f, true);
+      break;
+    }
+    case State::ePinching: {
+      MOZ_ASSERT(aNewState == State::eNone);
+      // ePinching -> eNone: PinchEnd. ePinching should only transition to
+      // eNone.
+      // Only send a pinch end if we sent a pinch start.
+      if (!mShouldSendPinchStart) {
+        SendPinch(Phase::eEnd, 0.f);
+      }
+      mShouldSendPinchStart = false;
+      break;
+    }
+    case State::eNone: {
+      // eNone -> *: no cleanup is needed.
+      break;
+    }
+    default:
+      MOZ_ASSERT(false);
+  }
+
+  // Start the new sequence.
+  switch (aNewState) {
+    case State::ePanning: {
+      // eInertia, eNone -> ePanning: PanStart.
+      // We're being called from OnContentUpdated, it has the coords we need to
+      // pass to SendPan(Phase::eStart), so set mShouldSendPanStart and when we
+      // return OnContentUpdated will check it and call SendPan(Phase::eStart).
+      mShouldSendPanStart = true;
+      break;
+    }
+    case State::eInertia: {
+      // Only ePanning can transition to eInertia.
+      MOZ_ASSERT(prevState == State::ePanning);
+      SendPan(Phase::eStart, 0.f, 0.f, true);
+      break;
+    }
+    case State::ePinching: {
+      // * -> ePinching: PinchStart.
+      // Pinch gesture may begin with some scroll events.
+      // We're being called from OnContentUpdated, it has the scale we need to
+      // pass to SendPinch(Phase::eStart), so set mShouldSendPinchStart and when
+      // we return OnContentUpdated will check it and call
+      // SendPinch(Phase::eStart).
+      mShouldSendPinchStart = true;
+      break;
+    }
+    case State::eNone: {
+      // * -> eNone: only cleanup is needed.
+      break;
+    }
+    default:
+      MOZ_ASSERT(false);
+  }
+}
+
+HRESULT
+DManipEventHandler::OnContentUpdated(IDirectManipulationViewport* viewport,
+                                     IDirectManipulationContent* content) {
+  float transform[6];
+  HRESULT hr = content->GetContentTransform(transform, ARRAYSIZE(transform));
+  if (!SUCCEEDED(hr)) {
+    NS_WARNING("GetContentTransform failed");
+    return S_OK;
+  }
+
+  float scale = transform[0];
+  float xoffset = transform[4];
+  float yoffset = transform[5];
+
+  // Not different from last time.
+  if (FuzzyEqualsMultiplicative(scale, mLastScale) && xoffset == mLastXOffset &&
+      yoffset == mLastYOffset) {
+    return S_OK;
+  }
+
+  // Consider this is a Scroll when scale factor equals 1.0.
+  if (FuzzyEqualsMultiplicative(scale, 1.f)) {
+    if (mState == State::eNone) {
+      TransitionToState(State::ePanning);
+    }
+  } else {
+    // Pinch gesture may begin with some scroll events.
+    TransitionToState(State::ePinching);
+  }
+
+  if (mState == State::ePanning || mState == State::eInertia) {
+    // Accumulate the offset (by not updating mLastX/YOffset) until we have at
+    // least one pixel.
+    float dx = std::abs(mLastXOffset - xoffset);
+    float dy = std::abs(mLastYOffset - yoffset);
+    if (dx < 1.f && dy < 1.f) {
+      return S_OK;
+    }
+  }
+
+  bool updateLastScale = true;
+  if (mState == State::ePanning) {
+    if (mShouldSendPanStart) {
+      SendPan(Phase::eStart, mLastXOffset - xoffset, mLastYOffset - yoffset,
+              false);
+      mShouldSendPanStart = false;
+    } else {
+      SendPan(Phase::eMiddle, mLastXOffset - xoffset, mLastYOffset - yoffset,
+              false);
+    }
+  } else if (mState == State::eInertia) {
+    SendPan(Phase::eMiddle, mLastXOffset - xoffset, mLastYOffset - yoffset,
+            true);
+  } else if (mState == State::ePinching) {
+    if (mShouldSendPinchStart) {
+      updateLastScale = SendPinch(Phase::eStart, scale);
+      // Only clear mShouldSendPinchStart if we actually sent the event
+      // (updateLastScale tells us if we sent an event).
+      if (updateLastScale) {
+        mShouldSendPinchStart = false;
+      }
+    } else {
+      updateLastScale = SendPinch(Phase::eMiddle, scale);
+    }
+  }
+
+  if (updateLastScale) {
+    mLastScale = scale;
+  }
+  mLastXOffset = xoffset;
+  mLastYOffset = yoffset;
+
+  return S_OK;
+}
+
+HRESULT
+DManipEventHandler::OnInteraction(
+    IDirectManipulationViewport2* viewport,
+    DIRECTMANIPULATION_INTERACTION_TYPE interaction) {
+  if (interaction == DIRECTMANIPULATION_INTERACTION_BEGIN) {
+    if (!mObserver) {
+      mObserver = new VObserver(this);
+    }
+
+    gfxWindowsPlatform::GetPlatform()
+        ->GetGlobalVsyncDispatcher()
+        ->AddMainThreadObserver(mObserver);
+  }
+
+  if (mObserver && interaction == DIRECTMANIPULATION_INTERACTION_END) {
+    gfxWindowsPlatform::GetPlatform()
+        ->GetGlobalVsyncDispatcher()
+        ->RemoveMainThreadObserver(mObserver);
+  }
+
+  return S_OK;
+}
+
+void DManipEventHandler::Update() {
+  if (mOwner) {
+    mOwner->Update();
+  }
+}
+
+void DirectManipulationOwner::Update() {
+  if (mDmUpdateManager) {
+    mDmUpdateManager->Update(nullptr);
+  }
+}
+
+DirectManipulationOwner::DirectManipulationOwner(nsWindow* aWindow)
+    : mWindow(aWindow) {}
+
+DirectManipulationOwner::~DirectManipulationOwner() { Destroy(); }
+
+bool DManipEventHandler::SendPinch(Phase aPhase, float aScale) {
+  if (!mWindow) {
+    return false;
+  }
+
+  if (aScale == mLastScale && aPhase != Phase::eEnd) {
+    return false;
+  }
+
+  PinchGestureInput::PinchGestureType pinchGestureType =
+      PinchGestureInput::PINCHGESTURE_SCALE;
+  switch (aPhase) {
+    case Phase::eStart:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_START;
+      break;
+    case Phase::eMiddle:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_SCALE;
+      break;
+    case Phase::eEnd:
+      pinchGestureType = PinchGestureInput::PINCHGESTURE_END;
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE("handle all enum values");
+  }
+
+  TimeStamp eventTimeStamp = TimeStamp::Now();
+
+  ModifierKeyState modifierKeyState;
+  Modifiers mods = modifierKeyState.GetModifiers();
+
+  ExternalPoint screenOffset = ViewAs<ExternalPixel>(
+      mWindow->WidgetToScreenOffset(),
+      PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent);
+
+  POINT cursor_pos;
+  ::GetCursorPos(&cursor_pos);
+  HWND wnd = static_cast<HWND>(mWindow->GetNativeData(NS_NATIVE_WINDOW));
+  ::ScreenToClient(wnd, &cursor_pos);
+  ScreenPoint position = {(float)cursor_pos.x, (float)cursor_pos.y};
+
+  PinchGestureInput event{pinchGestureType,
+                          PinchGestureInput::TRACKPAD,
+                          eventTimeStamp,
+                          screenOffset,
+                          position,
+                          100.0 * ((aPhase == Phase::eEnd) ? 1.f : aScale),
+                          100.0 * ((aPhase == Phase::eEnd) ? 1.f : mLastScale),
+                          mods};
+
+  if (!event.SetLineOrPageDeltaY(mWindow)) {
+    return false;
+  }
+
+  mWindow->SendAnAPZEvent(event);
+
+  return true;
+}
+
+void DManipEventHandler::SendPan(Phase aPhase, float x, float y,
+                                 bool aIsInertia) {
+  if (!mWindow) {
+    return;
+  }
+
+  ModifierKeyState modifierKeyState;
+  Modifiers mods = modifierKeyState.GetModifiers();
+
+  POINT cursor_pos;
+  ::GetCursorPos(&cursor_pos);
+  HWND wnd = static_cast<HWND>(mWindow->GetNativeData(NS_NATIVE_WINDOW));
+  ::ScreenToClient(wnd, &cursor_pos);
+  ScreenPoint position = {(float)cursor_pos.x, (float)cursor_pos.y};
+
+  SendPanCommon(mWindow, aPhase, position, x, y, mods, aIsInertia);
+}
+
+/* static */
+void DManipEventHandler::SendPanCommon(nsWindow* aWindow, Phase aPhase,
+                                       ScreenPoint aPosition, double aDeltaX,
+                                       double aDeltaY, Modifiers aMods,
+                                       bool aIsInertia) {
+  if (!aWindow) {
+    return;
+  }
+
+  PanGestureInput::PanGestureType panGestureType =
+      PanGestureInput::PANGESTURE_PAN;
+  if (aIsInertia) {
+    switch (aPhase) {
+      case Phase::eStart:
+        panGestureType = PanGestureInput::PANGESTURE_MOMENTUMSTART;
+        break;
+      case Phase::eMiddle:
+        panGestureType = PanGestureInput::PANGESTURE_MOMENTUMPAN;
+        break;
+      case Phase::eEnd:
+        panGestureType = PanGestureInput::PANGESTURE_MOMENTUMEND;
+        break;
+      default:
+        MOZ_ASSERT_UNREACHABLE("handle all enum values");
+    }
+  } else {
+    switch (aPhase) {
+      case Phase::eStart:
+        panGestureType = PanGestureInput::PANGESTURE_START;
+        break;
+      case Phase::eMiddle:
+        panGestureType = PanGestureInput::PANGESTURE_PAN;
+        break;
+      case Phase::eEnd:
+        panGestureType = PanGestureInput::PANGESTURE_END;
+        break;
+      default:
+        MOZ_ASSERT_UNREACHABLE("handle all enum values");
+    }
+  }
+
+  TimeStamp eventTimeStamp = TimeStamp::Now();
+
+  PanGestureInput event{panGestureType, eventTimeStamp, aPosition,
+                        ScreenPoint(aDeltaX, aDeltaY), aMods};
+
+  aWindow->SendAnAPZEvent(event);
+}
+
+void DirectManipulationOwner::Init(const LayoutDeviceIntRect& aBounds) {
+  HRESULT hr = CoCreateInstance(
+      CLSID_DirectManipulationManager, nullptr, CLSCTX_INPROC_SERVER,
+      IID_IDirectManipulationManager, getter_AddRefs(mDmManager));
+  if (!SUCCEEDED(hr)) {
+    NS_WARNING("CoCreateInstance(CLSID_DirectManipulationManager failed");
+    mDmManager = nullptr;
+    return;
+  }
+
+  hr = mDmManager->GetUpdateManager(IID_IDirectManipulationUpdateManager,
+                                    getter_AddRefs(mDmUpdateManager));
+  if (!SUCCEEDED(hr)) {
+    NS_WARNING("GetUpdateManager failed");
+    mDmManager = nullptr;
+    mDmUpdateManager = nullptr;
+    return;
+  }
+
+  HWND wnd = static_cast<HWND>(mWindow->GetNativeData(NS_NATIVE_WINDOW));
+
+  hr = mDmManager->CreateViewport(nullptr, wnd, IID_IDirectManipulationViewport,
+                                  getter_AddRefs(mDmViewport));
+  if (!SUCCEEDED(hr)) {
+    NS_WARNING("CreateViewport failed");
+    mDmManager = nullptr;
+    mDmUpdateManager = nullptr;
+    mDmViewport = nullptr;
+    return;
+  }
+
+  DIRECTMANIPULATION_CONFIGURATION configuration =
+      DIRECTMANIPULATION_CONFIGURATION_INTERACTION |
+      DIRECTMANIPULATION_CONFIGURATION_TRANSLATION_X |
+      DIRECTMANIPULATION_CONFIGURATION_TRANSLATION_Y |
+      DIRECTMANIPULATION_CONFIGURATION_TRANSLATION_INERTIA |
+      DIRECTMANIPULATION_CONFIGURATION_RAILS_X |
+      DIRECTMANIPULATION_CONFIGURATION_RAILS_Y;
+  if (StaticPrefs::apz_allow_zooming()) {
+    configuration |= DIRECTMANIPULATION_CONFIGURATION_SCALING;
+  }
+
+  hr = mDmViewport->ActivateConfiguration(configuration);
+  if (!SUCCEEDED(hr)) {
+    NS_WARNING("ActivateConfiguration failed");
+    mDmManager = nullptr;
+    mDmUpdateManager = nullptr;
+    mDmViewport = nullptr;
+    return;
+  }
+
+  hr = mDmViewport->SetViewportOptions(
+      DIRECTMANIPULATION_VIEWPORT_OPTIONS_MANUALUPDATE);
+  if (!SUCCEEDED(hr)) {
+    NS_WARNING("SetViewportOptions failed");
+    mDmManager = nullptr;
+    mDmUpdateManager = nullptr;
+    mDmViewport = nullptr;
+    return;
+  }
+
+  mDmHandler = new DManipEventHandler(mWindow, this, aBounds);
+
+  hr = mDmViewport->AddEventHandler(wnd, mDmHandler.get(),
+                                    &mDmViewportHandlerCookie);
+  if (!SUCCEEDED(hr)) {
+    NS_WARNING("AddEventHandler failed");
+    mDmManager = nullptr;
+    mDmUpdateManager = nullptr;
+    mDmViewport = nullptr;
+    mDmHandler = nullptr;
+    return;
+  }
+
+  RECT rect = {0, 0, aBounds.Width(), aBounds.Height()};
+  hr = mDmViewport->SetViewportRect(&rect);
+  if (!SUCCEEDED(hr)) {
+    NS_WARNING("SetViewportRect failed");
+    mDmManager = nullptr;
+    mDmUpdateManager = nullptr;
+    mDmViewport = nullptr;
+    mDmHandler = nullptr;
+    return;
+  }
+
+  hr = mDmManager->Activate(wnd);
+  if (!SUCCEEDED(hr)) {
+    NS_WARNING("manager Activate failed");
+    mDmManager = nullptr;
+    mDmUpdateManager = nullptr;
+    mDmViewport = nullptr;
+    mDmHandler = nullptr;
+    return;
+  }
+
+  hr = mDmViewport->Enable();
+  if (!SUCCEEDED(hr)) {
+    NS_WARNING("mDmViewport->Enable failed");
+    mDmManager = nullptr;
+    mDmUpdateManager = nullptr;
+    mDmViewport = nullptr;
+    mDmHandler = nullptr;
+    return;
+  }
+
+  hr = mDmUpdateManager->Update(nullptr);
+  if (!SUCCEEDED(hr)) {
+    NS_WARNING("mDmUpdateManager->Update failed");
+    mDmManager = nullptr;
+    mDmUpdateManager = nullptr;
+    mDmViewport = nullptr;
+    mDmHandler = nullptr;
+    return;
+  }
+}
+
+void DirectManipulationOwner::ResizeViewport(
+    const LayoutDeviceIntRect& aBounds) {
+  if (mDmHandler) {
+    mDmHandler->mBounds = aBounds;
+  }
+
+  if (mDmViewport) {
+    RECT rect = {0, 0, aBounds.Width(), aBounds.Height()};
+    HRESULT hr = mDmViewport->SetViewportRect(&rect);
+    if (!SUCCEEDED(hr)) {
+      NS_WARNING("SetViewportRect failed");
+    }
+  }
+}
+
+void DirectManipulationOwner::Destroy() {
+  if (mDmHandler) {
+    mDmHandler->mWindow = nullptr;
+    mDmHandler->mOwner = nullptr;
+    if (mDmHandler->mObserver) {
+      gfxWindowsPlatform::GetPlatform()
+          ->GetGlobalVsyncDispatcher()
+          ->RemoveMainThreadObserver(mDmHandler->mObserver);
+      mDmHandler->mObserver->ClearOwner();
+      mDmHandler->mObserver = nullptr;
+    }
+  }
+
+  HRESULT hr;
+  if (mDmViewport) {
+    hr = mDmViewport->Stop();
+    if (!SUCCEEDED(hr)) {
+      NS_WARNING("mDmViewport->Stop() failed");
+    }
+
+    hr = mDmViewport->Disable();
+    if (!SUCCEEDED(hr)) {
+      NS_WARNING("mDmViewport->Disable() failed");
+    }
+
+    hr = mDmViewport->RemoveEventHandler(mDmViewportHandlerCookie);
+    if (!SUCCEEDED(hr)) {
+      NS_WARNING("mDmViewport->RemoveEventHandler() failed");
+    }
+
+    hr = mDmViewport->Abandon();
+    if (!SUCCEEDED(hr)) {
+      NS_WARNING("mDmViewport->Abandon() failed");
+    }
+  }
+
+  if (mWindow) {
+    HWND wnd = static_cast<HWND>(mWindow->GetNativeData(NS_NATIVE_WINDOW));
+
+    if (mDmManager) {
+      hr = mDmManager->Deactivate(wnd);
+      if (!SUCCEEDED(hr)) {
+        NS_WARNING("mDmManager->Deactivate() failed");
+      }
+    }
+  }
+
+  mDmHandler = nullptr;
+  mDmViewport = nullptr;
+  mDmUpdateManager = nullptr;
+  mDmManager = nullptr;
+  mWindow = nullptr;
+}
+
+void DirectManipulationOwner::SetContact(UINT aContactId) {
+  if (mDmViewport) {
+    mDmViewport->SetContact(aContactId);
+  }
+}
+
+/*static  */ void DirectManipulationOwner::SynthesizeNativeTouchpadPan(
+    nsWindow* aWindow, nsIWidget::TouchpadGesturePhase aEventPhase,
+    LayoutDeviceIntPoint aPoint, double aDeltaX, double aDeltaY,
+    int32_t aModifierFlags) {
+  DManipEventHandler::SynthesizeNativeTouchpadPan(
+      aWindow, aEventPhase, aPoint, aDeltaX, aDeltaY, aModifierFlags);
+}
+
+/*static  */ void DManipEventHandler::SynthesizeNativeTouchpadPan(
+    nsWindow* aWindow, nsIWidget::TouchpadGesturePhase aEventPhase,
+    LayoutDeviceIntPoint aPoint, double aDeltaX, double aDeltaY,
+    int32_t aModifierFlags) {
+  ScreenPoint position = {(float)aPoint.x, (float)aPoint.y};
+  Phase phase = Phase::eStart;
+  if (aEventPhase == nsIWidget::PHASE_UPDATE) {
+    phase = Phase::eMiddle;
+  }
+
+  if (aEventPhase == nsIWidget::PHASE_END) {
+    phase = Phase::eEnd;
+  }
+  SendPanCommon(aWindow, phase, position, aDeltaX, aDeltaY, aModifierFlags,
+                /* aIsInertia = */ false);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/DirectManipulationOwner.h b/widget/windows/DirectManipulationOwner.h
new file mode 100644
index 0000000000..b4d5877d70
--- /dev/null
+++ b/widget/windows/DirectManipulationOwner.h
@@ -0,0 +1,54 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DirectManipulationOwner_h__
+#define DirectManipulationOwner_h__
+
+#include <windows.h>
+#include "Units.h"
+#include "nsIWidget.h"  // for TouchpadGesturePhase
+
+class nsWindow;
+class IDirectManipulationManager;
+class IDirectManipulationUpdateManager;
+class IDirectManipulationViewport;
+
+namespace mozilla {
+namespace widget {
+
+class DManipEventHandler;
+
+class DirectManipulationOwner {
+ public:
+  typedef mozilla::LayoutDeviceIntRect LayoutDeviceIntRect;
+
+  explicit DirectManipulationOwner(nsWindow* aWindow);
+  ~DirectManipulationOwner();
+  void Init(const LayoutDeviceIntRect& aBounds);
+  void ResizeViewport(const LayoutDeviceIntRect& aBounds);
+  void Destroy();
+
+  void SetContact(UINT aContactId);
+
+  void Update();
+
+  static void SynthesizeNativeTouchpadPan(
+      nsWindow* aWindow, nsIWidget::TouchpadGesturePhase aEventPhase,
+      LayoutDeviceIntPoint aPoint, double aDeltaX, double aDeltaY,
+      int32_t aModifierFlags);
+
+ private:
+  nsWindow* mWindow;
+  DWORD mDmViewportHandlerCookie;
+  RefPtr<IDirectManipulationManager> mDmManager;
+  RefPtr<IDirectManipulationUpdateManager> mDmUpdateManager;
+  RefPtr<IDirectManipulationViewport> mDmViewport;
+  RefPtr<DManipEventHandler> mDmHandler;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // #ifndef DirectManipulationOwner_h__
diff --git a/widget/windows/GfxInfo.cpp b/widget/windows/GfxInfo.cpp
new file mode 100644
index 0000000000..6f033785f5
--- /dev/null
+++ b/widget/windows/GfxInfo.cpp
@@ -0,0 +1,2082 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GfxInfo.h"
+
+#include "gfxConfig.h"
+#include "GfxDriverInfo.h"
+#include "gfxWindowsPlatform.h"
+#include "jsapi.h"
+#include "js/PropertyAndElement.h"  // JS_SetElement, JS_SetProperty
+#include "nsExceptionHandler.h"
+#include "nsPrintfCString.h"
+#include "nsUnicharUtils.h"
+#include "prenv.h"
+#include "prprf.h"
+#include "xpcpublic.h"
+
+#include "mozilla/Components.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/gfx/DeviceManagerDx.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/SSE.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/WindowsProcessMitigations.h"
+
+#include <intrin.h>
+#include <windows.h>
+#include <devguid.h>   // for GUID_DEVCLASS_BATTERY
+#include <setupapi.h>  // for SetupDi*
+#include <winioctl.h>  // for IOCTL_*
+#include <batclass.h>  // for BATTERY_*
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using namespace mozilla::widget;
+
+#ifdef DEBUG
+NS_IMPL_ISUPPORTS_INHERITED(GfxInfo, GfxInfoBase, nsIGfxInfoDebug)
+#endif
+
+static void AssertNotWin32kLockdown() {
+  // Check that we are not in Win32k lockdown
+  MOZ_DIAGNOSTIC_ASSERT(!IsWin32kLockedDown(),
+                        "Invalid Windows GfxInfo API with Win32k lockdown");
+}
+
+/* GetD2DEnabled and GetDwriteEnabled shouldn't be called until after
+ * gfxPlatform initialization has occurred because they depend on it for
+ * information. (See bug 591561) */
+nsresult GfxInfo::GetD2DEnabled(bool* aEnabled) {
+  // Telemetry queries this during XPCOM initialization, and there's no
+  // gfxPlatform by then. Just bail out if gfxPlatform isn't initialized.
+  if (!gfxPlatform::Initialized()) {
+    *aEnabled = false;
+    return NS_OK;
+  }
+
+  // We check gfxConfig rather than the actual render mode, since the UI
+  // process does not use Direct2D if the GPU process is enabled. However,
+  // content processes can still use Direct2D.
+  *aEnabled = gfx::gfxConfig::IsEnabled(gfx::Feature::DIRECT2D);
+  return NS_OK;
+}
+
+nsresult GfxInfo::GetDWriteEnabled(bool* aEnabled) {
+  *aEnabled = gfxWindowsPlatform::GetPlatform()->DWriteEnabled();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetDWriteVersion(nsAString& aDwriteVersion) {
+  gfxWindowsPlatform::GetDLLVersion(L"dwrite.dll", aDwriteVersion);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetHasBattery(bool* aHasBattery) {
+  AssertNotWin32kLockdown();
+
+  *aHasBattery = mHasBattery;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetEmbeddedInFirefoxReality(bool* aEmbeddedInFirefoxReality) {
+  *aEmbeddedInFirefoxReality = gfxVars::FxREmbedded();
+  return NS_OK;
+}
+
+#define PIXEL_STRUCT_RGB 1
+#define PIXEL_STRUCT_BGR 2
+
+NS_IMETHODIMP
+GfxInfo::GetCleartypeParameters(nsAString& aCleartypeParams) {
+  nsTArray<ClearTypeParameterInfo> clearTypeParams;
+
+  gfxWindowsPlatform::GetPlatform()->GetCleartypeParams(clearTypeParams);
+  uint32_t d, numDisplays = clearTypeParams.Length();
+  bool displayNames = (numDisplays > 1);
+  bool foundData = false;
+  nsString outStr;
+
+  for (d = 0; d < numDisplays; d++) {
+    ClearTypeParameterInfo& params = clearTypeParams[d];
+
+    if (displayNames) {
+      outStr.AppendPrintf(
+          "%S [ ", static_cast<const wchar_t*>(params.displayName.get()));
+    }
+
+    if (params.gamma >= 0) {
+      foundData = true;
+      outStr.AppendPrintf("Gamma: %.4g ", params.gamma / 1000.0);
+    }
+
+    if (params.pixelStructure >= 0) {
+      foundData = true;
+      if (params.pixelStructure == PIXEL_STRUCT_RGB ||
+          params.pixelStructure == PIXEL_STRUCT_BGR) {
+        outStr.AppendPrintf(
+            "Pixel Structure: %s ",
+            (params.pixelStructure == PIXEL_STRUCT_RGB ? "RGB" : "BGR"));
+      } else {
+        outStr.AppendPrintf("Pixel Structure: %d ", params.pixelStructure);
+      }
+    }
+
+    if (params.clearTypeLevel >= 0) {
+      foundData = true;
+      outStr.AppendPrintf("ClearType Level: %d ", params.clearTypeLevel);
+    }
+
+    if (params.enhancedContrast >= 0) {
+      foundData = true;
+      outStr.AppendPrintf("Enhanced Contrast: %d ", params.enhancedContrast);
+    }
+
+    if (displayNames) {
+      outStr.Append(u"] ");
+    }
+  }
+
+  if (foundData) {
+    aCleartypeParams.Assign(outStr);
+    return NS_OK;
+  }
+  return NS_ERROR_FAILURE;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetWindowProtocol(nsAString& aWindowProtocol) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetTestType(nsAString& aTestType) { return NS_ERROR_NOT_IMPLEMENTED; }
+
+static nsresult GetKeyValue(const WCHAR* keyLocation, const WCHAR* keyName,
+                            uint32_t& destValue, int type) {
+  MOZ_ASSERT(type == REG_DWORD || type == REG_QWORD);
+  HKEY key;
+  DWORD dwcbData;
+  DWORD dValue;
+  DWORD resultType;
+  LONG result;
+  nsresult retval = NS_OK;
+
+  result =
+      RegOpenKeyExW(HKEY_LOCAL_MACHINE, keyLocation, 0, KEY_QUERY_VALUE, &key);
+  if (result != ERROR_SUCCESS) {
+    return NS_ERROR_FAILURE;
+  }
+
+  switch (type) {
+    case REG_DWORD: {
+      // We only use this for vram size
+      dwcbData = sizeof(dValue);
+      result = RegQueryValueExW(key, keyName, nullptr, &resultType,
+                                (LPBYTE)&dValue, &dwcbData);
+      if (result == ERROR_SUCCESS && resultType == REG_DWORD) {
+        destValue = (uint32_t)(dValue / 1024 / 1024);
+      } else {
+        retval = NS_ERROR_FAILURE;
+      }
+      break;
+    }
+    case REG_QWORD: {
+      // We only use this for vram size
+      LONGLONG qValue;
+      dwcbData = sizeof(qValue);
+      result = RegQueryValueExW(key, keyName, nullptr, &resultType,
+                                (LPBYTE)&qValue, &dwcbData);
+      if (result == ERROR_SUCCESS && resultType == REG_QWORD) {
+        destValue = (uint32_t)(qValue / 1024 / 1024);
+      } else {
+        retval = NS_ERROR_FAILURE;
+      }
+      break;
+    }
+  }
+  RegCloseKey(key);
+
+  return retval;
+}
+
+static nsresult GetKeyValue(const WCHAR* keyLocation, const WCHAR* keyName,
+                            nsAString& destString, int type) {
+  MOZ_ASSERT(type == REG_MULTI_SZ);
+
+  HKEY key;
+  DWORD dwcbData;
+  DWORD resultType;
+  LONG result;
+  nsresult retval = NS_OK;
+
+  result =
+      RegOpenKeyExW(HKEY_LOCAL_MACHINE, keyLocation, 0, KEY_QUERY_VALUE, &key);
+  if (result != ERROR_SUCCESS) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // A chain of null-separated strings; we convert the nulls to spaces
+  WCHAR wCharValue[1024];
+  dwcbData = sizeof(wCharValue);
+
+  result = RegQueryValueExW(key, keyName, nullptr, &resultType,
+                            (LPBYTE)wCharValue, &dwcbData);
+  if (result == ERROR_SUCCESS && resultType == REG_MULTI_SZ) {
+    // This bit here could probably be cleaner.
+    bool isValid = false;
+
+    DWORD strLen = dwcbData / sizeof(wCharValue[0]);
+    for (DWORD i = 0; i < strLen; i++) {
+      if (wCharValue[i] == '\0') {
+        if (i < strLen - 1 && wCharValue[i + 1] == '\0') {
+          isValid = true;
+          break;
+        } else {
+          wCharValue[i] = ' ';
+        }
+      }
+    }
+
+    // ensure wCharValue is null terminated
+    wCharValue[strLen - 1] = '\0';
+
+    if (isValid) destString = wCharValue;
+
+  } else {
+    retval = NS_ERROR_FAILURE;
+  }
+
+  RegCloseKey(key);
+
+  return retval;
+}
+
+static nsresult GetKeyValues(const WCHAR* keyLocation, const WCHAR* keyName,
+                             nsTArray<nsString>& destStrings) {
+  // First ask for the size of the value
+  DWORD size;
+  LONG rv = RegGetValueW(HKEY_LOCAL_MACHINE, keyLocation, keyName,
+                         RRF_RT_REG_MULTI_SZ, nullptr, nullptr, &size);
+  if (rv != ERROR_SUCCESS) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Create a buffer with the proper size and retrieve the value
+  WCHAR* wCharValue = new WCHAR[size / sizeof(WCHAR)];
+  rv = RegGetValueW(HKEY_LOCAL_MACHINE, keyLocation, keyName,
+                    RRF_RT_REG_MULTI_SZ, nullptr, (LPBYTE)wCharValue, &size);
+  if (rv != ERROR_SUCCESS) {
+    delete[] wCharValue;
+    return NS_ERROR_FAILURE;
+  }
+
+  // The value is a sequence of null-terminated strings, usually terminated by
+  // an empty string (\0). RegGetValue ensures that the value is properly
+  // terminated with a null character.
+  DWORD i = 0;
+  DWORD strLen = size / sizeof(WCHAR);
+  while (i < strLen) {
+    nsString value(wCharValue + i);
+    if (!value.IsEmpty()) {
+      destStrings.AppendElement(value);
+    }
+    i += value.Length() + 1;
+  }
+  delete[] wCharValue;
+
+  return NS_OK;
+}
+
+// The device ID is a string like PCI\VEN_15AD&DEV_0405&SUBSYS_040515AD
+// this function is used to extract the id's out of it
+uint32_t ParseIDFromDeviceID(const nsAString& key, const nsAString& prefix,
+                             int length) {
+  nsAutoString id(key);
+  ToUpperCase(id);
+  int32_t start = id.Find(prefix);
+  if (start != -1) {
+    id.Cut(0, start + prefix.Length());
+    id.Truncate(length);
+  }
+  if (id.Equals(L"QCOM", nsCaseInsensitiveStringComparator)) {
+    // String format assumptions are broken, so use a Qualcomm PCI Vendor ID
+    // for now. See also GfxDriverInfo::GetDeviceVendor.
+    return 0x5143;
+  }
+  nsresult err;
+  return id.ToInteger(&err, 16);
+}
+
+// OS version in 16.16 major/minor form
+// based on http://msdn.microsoft.com/en-us/library/ms724834(VS.85).aspx
+enum {
+  kWindowsUnknown = 0,
+  kWindows7 = 0x60001,
+  kWindows8 = 0x60002,
+  kWindows8_1 = 0x60003,
+  kWindows10 = 0xA0000
+};
+
+static bool HasBattery() {
+  // Helper classes to manage lifetimes of Windows structs.
+  class MOZ_STACK_CLASS HDevInfoHolder final {
+   public:
+    explicit HDevInfoHolder(HDEVINFO aHandle) : mHandle(aHandle) {}
+
+    ~HDevInfoHolder() { ::SetupDiDestroyDeviceInfoList(mHandle); }
+
+   private:
+    HDEVINFO mHandle;
+  };
+
+  class MOZ_STACK_CLASS HandleHolder final {
+   public:
+    explicit HandleHolder(HANDLE aHandle) : mHandle(aHandle) {}
+
+    ~HandleHolder() { ::CloseHandle(mHandle); }
+
+   private:
+    HANDLE mHandle;
+  };
+
+  HDEVINFO hdev =
+      ::SetupDiGetClassDevs(&GUID_DEVCLASS_BATTERY, nullptr, nullptr,
+                            DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
+  if (hdev == INVALID_HANDLE_VALUE) {
+    return true;
+  }
+
+  HDevInfoHolder hdevHolder(hdev);
+
+  DWORD i = 0;
+  SP_DEVICE_INTERFACE_DATA did = {0};
+  did.cbSize = sizeof(did);
+
+  while (::SetupDiEnumDeviceInterfaces(hdev, nullptr, &GUID_DEVCLASS_BATTERY, i,
+                                       &did)) {
+    DWORD bufferSize = 0;
+    ::SetupDiGetDeviceInterfaceDetail(hdev, &did, nullptr, 0, &bufferSize,
+                                      nullptr);
+    if (::GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
+      return true;
+    }
+
+    UniquePtr<uint8_t[]> buffer(new (std::nothrow) uint8_t[bufferSize]);
+    if (!buffer) {
+      return true;
+    }
+
+    PSP_DEVICE_INTERFACE_DETAIL_DATA pdidd =
+        reinterpret_cast<PSP_DEVICE_INTERFACE_DETAIL_DATA>(buffer.get());
+    pdidd->cbSize = sizeof(*pdidd);
+    if (!::SetupDiGetDeviceInterfaceDetail(hdev, &did, pdidd, bufferSize,
+                                           &bufferSize, nullptr)) {
+      return true;
+    }
+
+    HANDLE hbat = ::CreateFile(pdidd->DevicePath, GENERIC_READ | GENERIC_WRITE,
+                               FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr,
+                               OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
+    if (hbat == INVALID_HANDLE_VALUE) {
+      return true;
+    }
+
+    HandleHolder hbatHolder(hbat);
+
+    BATTERY_QUERY_INFORMATION bqi = {0};
+    DWORD dwWait = 0;
+    DWORD dwOut;
+
+    // We need the tag to query the information below.
+    if (!::DeviceIoControl(hbat, IOCTL_BATTERY_QUERY_TAG, &dwWait,
+                           sizeof(dwWait), &bqi.BatteryTag,
+                           sizeof(bqi.BatteryTag), &dwOut, nullptr) ||
+        !bqi.BatteryTag) {
+      return true;
+    }
+
+    BATTERY_INFORMATION bi = {0};
+    bqi.InformationLevel = BatteryInformation;
+
+    if (!::DeviceIoControl(hbat, IOCTL_BATTERY_QUERY_INFORMATION, &bqi,
+                           sizeof(bqi), &bi, sizeof(bi), &dwOut, nullptr)) {
+      return true;
+    }
+
+    // If a battery intended for general use (i.e. system use) is not a UPS
+    // (i.e. short term), then we know for certain we have a battery.
+    if ((bi.Capabilities & BATTERY_SYSTEM_BATTERY) &&
+        !(bi.Capabilities & BATTERY_IS_SHORT_TERM)) {
+      return true;
+    }
+
+    // Otherwise we check the next battery.
+    ++i;
+  }
+
+  // If we fail to enumerate because there are no more batteries to check, then
+  // we can safely say there are indeed no system batteries.
+  return ::GetLastError() != ERROR_NO_MORE_ITEMS;
+}
+
+/* Other interesting places for info:
+ *   IDXGIAdapter::GetDesc()
+ *   IDirectDraw7::GetAvailableVidMem()
+ *   e->GetAvailableTextureMem()
+ * */
+
+#define DEVICE_KEY_PREFIX L"\\Registry\\Machine\\"
+nsresult GfxInfo::Init() {
+  nsresult rv = GfxInfoBase::Init();
+
+  // If we are locked down in a content process, we can't call any of the
+  // Win32k APIs below. Any method that accesses members of this class should
+  // assert that it's not used in content
+  if (IsWin32kLockedDown()) {
+    return rv;
+  }
+
+  mHasBattery = HasBattery();
+
+  DISPLAY_DEVICEW displayDevice;
+  displayDevice.cb = sizeof(displayDevice);
+  int deviceIndex = 0;
+
+  const char* spoofedWindowsVersion =
+      PR_GetEnv("MOZ_GFX_SPOOF_WINDOWS_VERSION");
+  if (spoofedWindowsVersion) {
+    PR_sscanf(spoofedWindowsVersion, "%x,%u", &mWindowsVersion,
+              &mWindowsBuildNumber);
+  } else {
+    OSVERSIONINFO vinfo;
+    vinfo.dwOSVersionInfoSize = sizeof(vinfo);
+#ifdef _MSC_VER
+#  pragma warning(push)
+#  pragma warning(disable : 4996)
+#endif
+    if (!GetVersionEx(&vinfo)) {
+#ifdef _MSC_VER
+#  pragma warning(pop)
+#endif
+      mWindowsVersion = kWindowsUnknown;
+    } else {
+      mWindowsVersion =
+          int32_t(vinfo.dwMajorVersion << 16) + vinfo.dwMinorVersion;
+      mWindowsBuildNumber = vinfo.dwBuildNumber;
+    }
+  }
+
+  mDeviceKeyDebug = u"PrimarySearch"_ns;
+
+  while (EnumDisplayDevicesW(nullptr, deviceIndex, &displayDevice, 0)) {
+    if (displayDevice.StateFlags & DISPLAY_DEVICE_PRIMARY_DEVICE) {
+      mDeviceKeyDebug = u"NullSearch"_ns;
+      break;
+    }
+    deviceIndex++;
+  }
+
+  // make sure the string is nullptr terminated
+  if (wcsnlen(displayDevice.DeviceKey, ArrayLength(displayDevice.DeviceKey)) ==
+      ArrayLength(displayDevice.DeviceKey)) {
+    // we did not find a nullptr
+    return rv;
+  }
+
+  mDeviceKeyDebug = displayDevice.DeviceKey;
+
+  /* DeviceKey is "reserved" according to MSDN so we'll be careful with it */
+  /* check that DeviceKey begins with DEVICE_KEY_PREFIX */
+  /* some systems have a DeviceKey starting with \REGISTRY\Machine\ so we need
+   * to compare case insenstively */
+  /* If the device key is empty, we are most likely in a remote desktop
+   * environment. In this case we set the devicekey to an empty string so
+   * it can be handled later.
+   */
+  if (displayDevice.DeviceKey[0] != '\0') {
+    if (_wcsnicmp(displayDevice.DeviceKey, DEVICE_KEY_PREFIX,
+                  ArrayLength(DEVICE_KEY_PREFIX) - 1) != 0) {
+      return rv;
+    }
+
+    // chop off DEVICE_KEY_PREFIX
+    mDeviceKey[0] =
+        displayDevice.DeviceKey + ArrayLength(DEVICE_KEY_PREFIX) - 1;
+  } else {
+    mDeviceKey[0].Truncate();
+  }
+
+  mDeviceID[0] = displayDevice.DeviceID;
+  mDeviceString[0] = displayDevice.DeviceString;
+
+  // On Windows 8 and Server 2012 hosts, we want to not block RDP
+  // sessions from attempting hardware acceleration.  RemoteFX
+  // provides features and functionaltiy that can give a good D3D10 +
+  // D2D + DirectWrite experience emulated via a software GPU.
+  //
+  // Unfortunately, the Device ID is nullptr, and we can't enumerate
+  // it using the setup infrastructure (SetupDiGetClassDevsW below
+  // will return INVALID_HANDLE_VALUE).
+  UINT flags = DIGCF_PRESENT | DIGCF_PROFILE | DIGCF_ALLCLASSES;
+  if (mWindowsVersion >= kWindows8 && mDeviceID[0].Length() == 0 &&
+      mDeviceString[0].EqualsLiteral("RDPUDD Chained DD")) {
+    WCHAR sysdir[255];
+    UINT len = GetSystemDirectory(sysdir, sizeof(sysdir));
+    if (len < sizeof(sysdir)) {
+      nsString rdpudd(sysdir);
+      rdpudd.AppendLiteral("\\rdpudd.dll");
+      gfxWindowsPlatform::GetDLLVersion(rdpudd.BeginReading(),
+                                        mDriverVersion[0]);
+      mDriverDate[0].AssignLiteral("01-01-1970");
+
+      // 0x1414 is Microsoft; 0xfefe is an invented (and unused) code
+      mDeviceID[0].AssignLiteral("PCI\\VEN_1414&DEV_FEFE&SUBSYS_00000000");
+      flags |= DIGCF_DEVICEINTERFACE;
+    }
+  }
+
+  /* create a device information set composed of the current display device */
+  HDEVINFO devinfo =
+      SetupDiGetClassDevsW(nullptr, mDeviceID[0].get(), nullptr, flags);
+
+  if (devinfo != INVALID_HANDLE_VALUE) {
+    HKEY key;
+    LONG result;
+    WCHAR value[255];
+    DWORD dwcbData;
+    SP_DEVINFO_DATA devinfoData;
+    DWORD memberIndex = 0;
+
+    devinfoData.cbSize = sizeof(devinfoData);
+    constexpr auto driverKeyPre =
+        u"System\\CurrentControlSet\\Control\\Class\\"_ns;
+    /* enumerate device information elements in the device information set */
+    while (SetupDiEnumDeviceInfo(devinfo, memberIndex++, &devinfoData)) {
+      /* get a string that identifies the device's driver key */
+      if (SetupDiGetDeviceRegistryPropertyW(devinfo, &devinfoData, SPDRP_DRIVER,
+                                            nullptr, (PBYTE)value,
+                                            sizeof(value), nullptr)) {
+        nsAutoString driverKey(driverKeyPre);
+        driverKey += value;
+        result = RegOpenKeyExW(HKEY_LOCAL_MACHINE, driverKey.get(), 0,
+                               KEY_QUERY_VALUE, &key);
+        if (result == ERROR_SUCCESS) {
+          /* we've found the driver we're looking for */
+          dwcbData = sizeof(value);
+          result = RegQueryValueExW(key, L"DriverVersion", nullptr, nullptr,
+                                    (LPBYTE)value, &dwcbData);
+          if (result == ERROR_SUCCESS) {
+            mDriverVersion[0] = value;
+          } else {
+            // If the entry wasn't found, assume the worst (0.0.0.0).
+            mDriverVersion[0].AssignLiteral("0.0.0.0");
+          }
+          dwcbData = sizeof(value);
+          result = RegQueryValueExW(key, L"DriverDate", nullptr, nullptr,
+                                    (LPBYTE)value, &dwcbData);
+          if (result == ERROR_SUCCESS) {
+            mDriverDate[0] = value;
+          } else {
+            // Again, assume the worst
+            mDriverDate[0].AssignLiteral("01-01-1970");
+          }
+          RegCloseKey(key);
+          break;
+        }
+      }
+    }
+
+    SetupDiDestroyDeviceInfoList(devinfo);
+  }
+
+  // It is convenient to have these as integers
+  uint32_t adapterVendorID[2] = {0, 0};
+  uint32_t adapterDeviceID[2] = {0, 0};
+  uint32_t adapterSubsysID[2] = {0, 0};
+
+  adapterVendorID[0] = ParseIDFromDeviceID(mDeviceID[0], u"VEN_"_ns, 4);
+  adapterDeviceID[0] = ParseIDFromDeviceID(mDeviceID[0], u"&DEV_"_ns, 4);
+  adapterSubsysID[0] = ParseIDFromDeviceID(mDeviceID[0], u"&SUBSYS_"_ns, 8);
+
+  // Sometimes we don't get the valid device using this method.  For now,
+  // allow zero vendor or device as valid, as long as the other value is
+  // non-zero.
+  bool foundValidDevice = (adapterVendorID[0] != 0 || adapterDeviceID[0] != 0);
+
+  // We now check for second display adapter.  If we didn't find the valid
+  // device using the original approach, we will try the alternative.
+
+  // Device interface class for display adapters.
+  CLSID GUID_DISPLAY_DEVICE_ARRIVAL;
+  HRESULT hresult = CLSIDFromString(L"{1CA05180-A699-450A-9A0C-DE4FBE3DDD89}",
+                                    &GUID_DISPLAY_DEVICE_ARRIVAL);
+  if (hresult == NOERROR) {
+    devinfo =
+        SetupDiGetClassDevsW(&GUID_DISPLAY_DEVICE_ARRIVAL, nullptr, nullptr,
+                             DIGCF_PRESENT | DIGCF_INTERFACEDEVICE);
+
+    if (devinfo != INVALID_HANDLE_VALUE) {
+      HKEY key;
+      LONG result;
+      WCHAR value[255];
+      DWORD dwcbData;
+      SP_DEVINFO_DATA devinfoData;
+      DWORD memberIndex = 0;
+      devinfoData.cbSize = sizeof(devinfoData);
+
+      nsAutoString adapterDriver2;
+      nsAutoString deviceID2;
+      nsAutoString driverVersion2;
+      nsAutoString driverDate2;
+
+      constexpr auto driverKeyPre =
+          u"System\\CurrentControlSet\\Control\\Class\\"_ns;
+      /* enumerate device information elements in the device information set */
+      while (SetupDiEnumDeviceInfo(devinfo, memberIndex++, &devinfoData)) {
+        /* get a string that identifies the device's driver key */
+        if (SetupDiGetDeviceRegistryPropertyW(
+                devinfo, &devinfoData, SPDRP_DRIVER, nullptr, (PBYTE)value,
+                sizeof(value), nullptr)) {
+          nsAutoString driverKey2(driverKeyPre);
+          driverKey2 += value;
+          result = RegOpenKeyExW(HKEY_LOCAL_MACHINE, driverKey2.get(), 0,
+                                 KEY_QUERY_VALUE, &key);
+          if (result == ERROR_SUCCESS) {
+            dwcbData = sizeof(value);
+            result = RegQueryValueExW(key, L"MatchingDeviceId", nullptr,
+                                      nullptr, (LPBYTE)value, &dwcbData);
+            if (result != ERROR_SUCCESS) {
+              continue;
+            }
+            deviceID2 = value;
+            adapterVendorID[1] = ParseIDFromDeviceID(deviceID2, u"VEN_"_ns, 4);
+            adapterDeviceID[1] = ParseIDFromDeviceID(deviceID2, u"&DEV_"_ns, 4);
+            // Skip the devices we already considered, as well as any
+            // "zero" ones.
+            if ((adapterVendorID[0] == adapterVendorID[1] &&
+                 adapterDeviceID[0] == adapterDeviceID[1]) ||
+                (adapterVendorID[1] == 0 && adapterDeviceID[1] == 0)) {
+              RegCloseKey(key);
+              continue;
+            }
+
+            // If this device is missing driver information, it is unlikely to
+            // be a real display adapter.
+            if (NS_FAILED(GetKeyValue(driverKey2.get(),
+                                      L"InstalledDisplayDrivers",
+                                      adapterDriver2, REG_MULTI_SZ))) {
+              RegCloseKey(key);
+              continue;
+            }
+            dwcbData = sizeof(value);
+            result = RegQueryValueExW(key, L"DriverVersion", nullptr, nullptr,
+                                      (LPBYTE)value, &dwcbData);
+            if (result != ERROR_SUCCESS) {
+              RegCloseKey(key);
+              continue;
+            }
+            driverVersion2 = value;
+            dwcbData = sizeof(value);
+            result = RegQueryValueExW(key, L"DriverDate", nullptr, nullptr,
+                                      (LPBYTE)value, &dwcbData);
+            if (result != ERROR_SUCCESS) {
+              RegCloseKey(key);
+              continue;
+            }
+            driverDate2 = value;
+            dwcbData = sizeof(value);
+            result = RegQueryValueExW(key, L"Device Description", nullptr,
+                                      nullptr, (LPBYTE)value, &dwcbData);
+            if (result != ERROR_SUCCESS) {
+              dwcbData = sizeof(value);
+              result = RegQueryValueExW(key, L"DriverDesc", nullptr, nullptr,
+                                        (LPBYTE)value, &dwcbData);
+            }
+            RegCloseKey(key);
+            if (result == ERROR_SUCCESS) {
+              // If we didn't find a valid device with the original method
+              // take this one, and continue looking for the second GPU.
+              if (!foundValidDevice) {
+                foundValidDevice = true;
+                adapterVendorID[0] = adapterVendorID[1];
+                adapterDeviceID[0] = adapterDeviceID[1];
+                mDeviceString[0] = value;
+                mDeviceID[0] = deviceID2;
+                mDeviceKey[0] = driverKey2;
+                mDriverVersion[0] = driverVersion2;
+                mDriverDate[0] = driverDate2;
+                adapterSubsysID[0] =
+                    ParseIDFromDeviceID(mDeviceID[0], u"&SUBSYS_"_ns, 8);
+                continue;
+              }
+
+              mHasDualGPU = true;
+              mDeviceString[1] = value;
+              mDeviceID[1] = deviceID2;
+              mDeviceKey[1] = driverKey2;
+              mDriverVersion[1] = driverVersion2;
+              mDriverDate[1] = driverDate2;
+              adapterSubsysID[1] =
+                  ParseIDFromDeviceID(mDeviceID[1], u"&SUBSYS_"_ns, 8);
+              mAdapterVendorID[1].AppendPrintf("0x%04x", adapterVendorID[1]);
+              mAdapterDeviceID[1].AppendPrintf("0x%04x", adapterDeviceID[1]);
+              mAdapterSubsysID[1].AppendPrintf("%08x", adapterSubsysID[1]);
+              break;
+            }
+          }
+        }
+      }
+
+      SetupDiDestroyDeviceInfoList(devinfo);
+    }
+  }
+
+  mAdapterVendorID[0].AppendPrintf("0x%04x", adapterVendorID[0]);
+  mAdapterDeviceID[0].AppendPrintf("0x%04x", adapterDeviceID[0]);
+  mAdapterSubsysID[0].AppendPrintf("%08x", adapterSubsysID[0]);
+
+  // Sometimes, the enumeration is not quite right and the two adapters
+  // end up being swapped.  Actually enumerate the adapters that come
+  // back from the DXGI factory to check, and tag the second as active
+  // if found.
+  if (mHasDualGPU) {
+    nsModuleHandle dxgiModule(LoadLibrarySystem32(L"dxgi.dll"));
+    decltype(CreateDXGIFactory)* createDXGIFactory =
+        (decltype(CreateDXGIFactory)*)GetProcAddress(dxgiModule,
+                                                     "CreateDXGIFactory");
+
+    if (createDXGIFactory) {
+      RefPtr<IDXGIFactory> factory = nullptr;
+      createDXGIFactory(__uuidof(IDXGIFactory), (void**)(&factory));
+      if (factory) {
+        RefPtr<IDXGIAdapter> adapter;
+        if (SUCCEEDED(factory->EnumAdapters(0, getter_AddRefs(adapter)))) {
+          DXGI_ADAPTER_DESC desc;
+          PodZero(&desc);
+          if (SUCCEEDED(adapter->GetDesc(&desc))) {
+            if (desc.VendorId != adapterVendorID[0] &&
+                desc.DeviceId != adapterDeviceID[0] &&
+                desc.VendorId == adapterVendorID[1] &&
+                desc.DeviceId == adapterDeviceID[1]) {
+              mActiveGPUIndex = 1;
+            }
+          }
+        }
+      }
+    }
+  }
+
+  mHasDriverVersionMismatch = false;
+  if (mAdapterVendorID[mActiveGPUIndex] ==
+      GfxDriverInfo::GetDeviceVendor(DeviceVendor::Intel)) {
+    // we've had big crashers (bugs 590373 and 595364) apparently correlated
+    // with bad Intel driver installations where the DriverVersion reported
+    // by the registry was not the version of the DLL.
+
+    // Note that these start without the .dll extension but eventually gain it.
+    bool is64bitApp = sizeof(void*) == 8;
+    nsAutoString dllFileName(is64bitApp ? u"igd10umd64" : u"igd10umd32");
+    nsAutoString dllFileName2(is64bitApp ? u"igd10iumd64" : u"igd10iumd32");
+
+    nsString dllVersion, dllVersion2;
+    uint64_t dllNumericVersion = 0, dllNumericVersion2 = 0,
+             driverNumericVersion = 0, knownSafeMismatchVersion = 0;
+
+    // Only parse the DLL version for those found in the driver list
+    nsAutoString eligibleDLLs;
+    if (NS_SUCCEEDED(GetAdapterDriver(eligibleDLLs))) {
+      if (FindInReadable(dllFileName, eligibleDLLs)) {
+        dllFileName += u".dll"_ns;
+        gfxWindowsPlatform::GetDLLVersion(dllFileName.get(), dllVersion);
+        ParseDriverVersion(dllVersion, &dllNumericVersion);
+      }
+      if (FindInReadable(dllFileName2, eligibleDLLs)) {
+        dllFileName2 += u".dll"_ns;
+        gfxWindowsPlatform::GetDLLVersion(dllFileName2.get(), dllVersion2);
+        ParseDriverVersion(dllVersion2, &dllNumericVersion2);
+      }
+    }
+
+    // Sometimes the DLL is not in the System32 nor SysWOW64 directories. But
+    // UserModeDriverName (or UserModeDriverNameWow, if available) might provide
+    // the full path to the DLL in some DriverStore FileRepository.
+    if (dllNumericVersion == 0 && dllNumericVersion2 == 0) {
+      nsTArray<nsString> eligibleDLLpaths;
+      const WCHAR* keyLocation = mDeviceKey[mActiveGPUIndex].get();
+      GetKeyValues(keyLocation, L"UserModeDriverName", eligibleDLLpaths);
+      GetKeyValues(keyLocation, L"UserModeDriverNameWow", eligibleDLLpaths);
+      size_t length = eligibleDLLpaths.Length();
+      for (size_t i = 0;
+           i < length && dllNumericVersion == 0 && dllNumericVersion2 == 0;
+           ++i) {
+        if (FindInReadable(dllFileName, eligibleDLLpaths[i])) {
+          gfxWindowsPlatform::GetDLLVersion(eligibleDLLpaths[i].get(),
+                                            dllVersion);
+          ParseDriverVersion(dllVersion, &dllNumericVersion);
+        } else if (FindInReadable(dllFileName2, eligibleDLLpaths[i])) {
+          gfxWindowsPlatform::GetDLLVersion(eligibleDLLpaths[i].get(),
+                                            dllVersion2);
+          ParseDriverVersion(dllVersion2, &dllNumericVersion2);
+        }
+      }
+    }
+
+    ParseDriverVersion(mDriverVersion[mActiveGPUIndex], &driverNumericVersion);
+    ParseDriverVersion(u"9.17.10.0"_ns, &knownSafeMismatchVersion);
+
+    // If there's a driver version mismatch, consider this harmful only when
+    // the driver version is less than knownSafeMismatchVersion.  See the
+    // above comment about crashes with old mismatches.  If the GetDllVersion
+    // call fails, we are not calling it a mismatch.
+    if ((dllNumericVersion != 0 && dllNumericVersion != driverNumericVersion) ||
+        (dllNumericVersion2 != 0 &&
+         dllNumericVersion2 != driverNumericVersion)) {
+      if (driverNumericVersion < knownSafeMismatchVersion ||
+          std::max(dllNumericVersion, dllNumericVersion2) <
+              knownSafeMismatchVersion) {
+        mHasDriverVersionMismatch = true;
+        gfxCriticalNoteOnce
+            << "Mismatched driver versions between the registry "
+            << NS_ConvertUTF16toUTF8(mDriverVersion[mActiveGPUIndex]).get()
+            << " and DLL(s) " << NS_ConvertUTF16toUTF8(dllVersion).get() << ", "
+            << NS_ConvertUTF16toUTF8(dllVersion2).get() << " reported.";
+      }
+    } else if (dllNumericVersion == 0 && dllNumericVersion2 == 0) {
+      // Leave it as an asserting error for now, to see if we can find
+      // a system that exhibits this kind of a problem internally.
+      gfxCriticalErrorOnce()
+          << "Potential driver version mismatch ignored due to missing DLLs "
+          << NS_ConvertUTF16toUTF8(dllFileName).get()
+          << " v=" << NS_ConvertUTF16toUTF8(dllVersion).get() << " and "
+          << NS_ConvertUTF16toUTF8(dllFileName2).get()
+          << " v=" << NS_ConvertUTF16toUTF8(dllVersion2).get();
+    }
+  }
+
+  const char* spoofedDriverVersionString =
+      PR_GetEnv("MOZ_GFX_SPOOF_DRIVER_VERSION");
+  if (spoofedDriverVersionString) {
+    mDriverVersion[mActiveGPUIndex].AssignASCII(spoofedDriverVersionString);
+  }
+
+  const char* spoofedVendor = PR_GetEnv("MOZ_GFX_SPOOF_VENDOR_ID");
+  if (spoofedVendor) {
+    mAdapterVendorID[mActiveGPUIndex].AssignASCII(spoofedVendor);
+  }
+
+  const char* spoofedDevice = PR_GetEnv("MOZ_GFX_SPOOF_DEVICE_ID");
+  if (spoofedDevice) {
+    mAdapterDeviceID[mActiveGPUIndex].AssignASCII(spoofedDevice);
+  }
+
+  AddCrashReportAnnotations();
+
+  return rv;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDescription(nsAString& aAdapterDescription) {
+  AssertNotWin32kLockdown();
+
+  aAdapterDescription = mDeviceString[mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDescription2(nsAString& aAdapterDescription) {
+  AssertNotWin32kLockdown();
+
+  aAdapterDescription = mDeviceString[1 - mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterRAM(uint32_t* aAdapterRAM) {
+  AssertNotWin32kLockdown();
+
+  uint32_t result = 0;
+  if (NS_FAILED(GetKeyValue(mDeviceKey[mActiveGPUIndex].get(),
+                            L"HardwareInformation.qwMemorySize", result,
+                            REG_QWORD)) ||
+      result == 0) {
+    if (NS_FAILED(GetKeyValue(mDeviceKey[mActiveGPUIndex].get(),
+                              L"HardwareInformation.MemorySize", result,
+                              REG_DWORD))) {
+      result = 0;
+    }
+  }
+  *aAdapterRAM = result;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterRAM2(uint32_t* aAdapterRAM) {
+  AssertNotWin32kLockdown();
+
+  uint32_t result = 0;
+  if (mHasDualGPU) {
+    if (NS_FAILED(GetKeyValue(mDeviceKey[1 - mActiveGPUIndex].get(),
+                              L"HardwareInformation.qwMemorySize", result,
+                              REG_QWORD)) ||
+        result == 0) {
+      if (NS_FAILED(GetKeyValue(mDeviceKey[1 - mActiveGPUIndex].get(),
+                                L"HardwareInformation.MemorySize", result,
+                                REG_DWORD))) {
+        result = 0;
+      }
+    }
+  }
+  *aAdapterRAM = result;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriver(nsAString& aAdapterDriver) {
+  AssertNotWin32kLockdown();
+
+  if (NS_FAILED(GetKeyValue(mDeviceKey[mActiveGPUIndex].get(),
+                            L"InstalledDisplayDrivers", aAdapterDriver,
+                            REG_MULTI_SZ)))
+    aAdapterDriver = L"Unknown";
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriver2(nsAString& aAdapterDriver) {
+  AssertNotWin32kLockdown();
+
+  if (!mHasDualGPU) {
+    aAdapterDriver.Truncate();
+  } else if (NS_FAILED(GetKeyValue(mDeviceKey[1 - mActiveGPUIndex].get(),
+                                   L"InstalledDisplayDrivers", aAdapterDriver,
+                                   REG_MULTI_SZ))) {
+    aAdapterDriver = L"Unknown";
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVendor(nsAString& aAdapterDriverVendor) {
+  aAdapterDriverVendor.Truncate();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVersion(nsAString& aAdapterDriverVersion) {
+  AssertNotWin32kLockdown();
+
+  aAdapterDriverVersion = mDriverVersion[mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverDate(nsAString& aAdapterDriverDate) {
+  AssertNotWin32kLockdown();
+
+  aAdapterDriverDate = mDriverDate[mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVendor2(nsAString& aAdapterDriverVendor) {
+  aAdapterDriverVendor.Truncate();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverVersion2(nsAString& aAdapterDriverVersion) {
+  AssertNotWin32kLockdown();
+
+  aAdapterDriverVersion = mDriverVersion[1 - mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDriverDate2(nsAString& aAdapterDriverDate) {
+  AssertNotWin32kLockdown();
+
+  aAdapterDriverDate = mDriverDate[1 - mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterVendorID(nsAString& aAdapterVendorID) {
+  AssertNotWin32kLockdown();
+
+  aAdapterVendorID = mAdapterVendorID[mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterVendorID2(nsAString& aAdapterVendorID) {
+  AssertNotWin32kLockdown();
+
+  aAdapterVendorID = mAdapterVendorID[1 - mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDeviceID(nsAString& aAdapterDeviceID) {
+  AssertNotWin32kLockdown();
+
+  aAdapterDeviceID = mAdapterDeviceID[mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterDeviceID2(nsAString& aAdapterDeviceID) {
+  AssertNotWin32kLockdown();
+
+  aAdapterDeviceID = mAdapterDeviceID[1 - mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterSubsysID(nsAString& aAdapterSubsysID) {
+  AssertNotWin32kLockdown();
+
+  aAdapterSubsysID = mAdapterSubsysID[mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetAdapterSubsysID2(nsAString& aAdapterSubsysID) {
+  AssertNotWin32kLockdown();
+
+  aAdapterSubsysID = mAdapterSubsysID[1 - mActiveGPUIndex];
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetIsGPU2Active(bool* aIsGPU2Active) {
+  // This is never the case, as the active GPU ends up being
+  // the first one.  It should probably be removed.
+  *aIsGPU2Active = false;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+GfxInfo::GetDrmRenderDevice(nsACString& aDrmRenderDevice) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+/* Cisco's VPN software can cause corruption of the floating point state.
+ * Make a note of this in our crash reports so that some weird crashes
+ * make more sense */
+static void CheckForCiscoVPN() {
+  LONG result;
+  HKEY key;
+  /* This will give false positives, but hopefully no false negatives */
+  result =
+      RegOpenKeyExW(HKEY_LOCAL_MACHINE, L"Software\\Cisco Systems\\VPN Client",
+                    0, KEY_QUERY_VALUE, &key);
+  if (result == ERROR_SUCCESS) {
+    RegCloseKey(key);
+    CrashReporter::AppendAppNotesToCrashReport("Cisco VPN\n"_ns);
+  }
+}
+
+void GfxInfo::AddCrashReportAnnotations() {
+  AssertNotWin32kLockdown();
+
+  CheckForCiscoVPN();
+
+  if (mHasDriverVersionMismatch) {
+    CrashReporter::AppendAppNotesToCrashReport("DriverVersionMismatch\n"_ns);
+  }
+
+  nsString deviceID, vendorID, driverVersion, subsysID;
+  nsCString narrowDeviceID, narrowVendorID, narrowDriverVersion, narrowSubsysID;
+
+  GetAdapterDeviceID(deviceID);
+  CopyUTF16toUTF8(deviceID, narrowDeviceID);
+  GetAdapterVendorID(vendorID);
+  CopyUTF16toUTF8(vendorID, narrowVendorID);
+  GetAdapterDriverVersion(driverVersion);
+  CopyUTF16toUTF8(driverVersion, narrowDriverVersion);
+  GetAdapterSubsysID(subsysID);
+  CopyUTF16toUTF8(subsysID, narrowSubsysID);
+
+  CrashReporter::AnnotateCrashReport(CrashReporter::Annotation::AdapterVendorID,
+                                     narrowVendorID);
+  CrashReporter::AnnotateCrashReport(CrashReporter::Annotation::AdapterDeviceID,
+                                     narrowDeviceID);
+  CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::AdapterDriverVersion, narrowDriverVersion);
+  CrashReporter::AnnotateCrashReport(CrashReporter::Annotation::AdapterSubsysID,
+                                     narrowSubsysID);
+
+  /* Add an App Note, this contains extra information. */
+  nsAutoCString note;
+
+  // TODO: We should probably convert this into a proper annotation
+  if (vendorID == GfxDriverInfo::GetDeviceVendor(DeviceVendor::All)) {
+    /* if we didn't find a valid vendorID lets append the mDeviceID string to
+     * try to find out why */
+    LossyAppendUTF16toASCII(mDeviceID[mActiveGPUIndex], note);
+    note.AppendLiteral(", ");
+    LossyAppendUTF16toASCII(mDeviceKeyDebug, note);
+  }
+  note.AppendLiteral("\n");
+
+  if (mHasDualGPU) {
+    nsString deviceID2, vendorID2, subsysID2;
+    nsAutoString adapterDriverVersionString2;
+    nsCString narrowDeviceID2, narrowVendorID2, narrowSubsysID2;
+
+    // Make a slight difference between the two cases so that we
+    // can see it in the crash reports.  It may come in handy.
+    if (mActiveGPUIndex == 1) {
+      note.AppendLiteral("Has dual GPUs. GPU-#2: ");
+    } else {
+      note.AppendLiteral("Has dual GPUs. GPU #2: ");
+    }
+    GetAdapterDeviceID2(deviceID2);
+    CopyUTF16toUTF8(deviceID2, narrowDeviceID2);
+    GetAdapterVendorID2(vendorID2);
+    CopyUTF16toUTF8(vendorID2, narrowVendorID2);
+    GetAdapterDriverVersion2(adapterDriverVersionString2);
+    GetAdapterSubsysID(subsysID2);
+    CopyUTF16toUTF8(subsysID2, narrowSubsysID2);
+    note.AppendLiteral("AdapterVendorID2: ");
+    note.Append(narrowVendorID2);
+    note.AppendLiteral(", AdapterDeviceID2: ");
+    note.Append(narrowDeviceID2);
+    note.AppendLiteral(", AdapterSubsysID2: ");
+    note.Append(narrowSubsysID2);
+    note.AppendLiteral(", AdapterDriverVersion2: ");
+    note.Append(NS_LossyConvertUTF16toASCII(adapterDriverVersionString2));
+  }
+  CrashReporter::AppendAppNotesToCrashReport(note);
+}
+
+static OperatingSystem WindowsVersionToOperatingSystem(
+    int32_t aWindowsVersion) {
+  switch (aWindowsVersion) {
+    case kWindows7:
+      return OperatingSystem::Windows7;
+    case kWindows8:
+      return OperatingSystem::Windows8;
+    case kWindows8_1:
+      return OperatingSystem::Windows8_1;
+    case kWindows10:
+      return OperatingSystem::Windows10;
+    case kWindowsUnknown:
+    default:
+      return OperatingSystem::Unknown;
+  }
+}
+
+// Return true if the CPU supports AVX, but the operating system does not.
+#if defined(_M_X64)
+static inline bool DetectBrokenAVX() {
+  int regs[4];
+  __cpuid(regs, 0);
+  if (regs[0] == 0) {
+    // Level not supported.
+    return false;
+  }
+
+  __cpuid(regs, 1);
+
+  const unsigned AVX = 1u << 28;
+  const unsigned XSAVE = 1u << 26;
+  if ((regs[2] & (AVX | XSAVE)) != (AVX | XSAVE)) {
+    // AVX is not supported on this CPU.
+    return false;
+  }
+
+  const unsigned OSXSAVE = 1u << 27;
+  if ((regs[2] & OSXSAVE) != OSXSAVE) {
+    // AVX is supported, but the OS didn't enable it.
+    // This can be forced via bcdedit /set xsavedisable 1.
+    return true;
+  }
+
+  const unsigned AVX_CTRL_BITS = (1 << 1) | (1 << 2);
+  return (xgetbv(0) & AVX_CTRL_BITS) != AVX_CTRL_BITS;
+}
+#endif
+
+const nsTArray<GfxDriverInfo>& GfxInfo::GetGfxDriverInfo() {
+  if (!sDriverInfo->Length()) {
+    /*
+     * It should be noted here that more specialized rules on certain features
+     * should be inserted -before- more generalized restriction. As the first
+     * match for feature/OS/device found in the list will be used for the final
+     * blocklisting call.
+     */
+
+    /*
+     * NVIDIA entries
+     */
+    /*
+     * The last 5 digit of the NVIDIA driver version maps to the version that
+     * NVIDIA uses. The minor version (15, 16, 17) corresponds roughtly to the
+     * OS (Vista, Win7, Win7) but they show up in smaller numbers across all
+     * OS versions (perhaps due to OS upgrades). So we want to support
+     * October 2009+ drivers across all these minor versions.
+     *
+     * 187.45 (late October 2009) and earlier contain a bug which can cause us
+     * to crash on shutdown.
+     */
+    APPEND_TO_DRIVER_BLOCKLIST(
+        OperatingSystem::Windows7, DeviceFamily::NvidiaAll,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN_OR_EQUAL,
+        V(8, 15, 11, 8745), "FEATURE_FAILURE_NV_W7_15",
+        "nVidia driver > 187.45");
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows7, DeviceFamily::NvidiaAll,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+        DRIVER_BETWEEN_INCLUSIVE_START, V(8, 16, 10, 0000), V(8, 16, 11, 8745),
+        "FEATURE_FAILURE_NV_W7_16", "nVidia driver > 187.45");
+    // Telemetry doesn't show any driver in this range so it might not even be
+    // required.
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows7, DeviceFamily::NvidiaAll,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+        DRIVER_BETWEEN_INCLUSIVE_START, V(8, 17, 10, 0000), V(8, 17, 11, 8745),
+        "FEATURE_FAILURE_NV_W7_17", "nVidia driver > 187.45");
+
+    /*
+     * AMD/ATI entries. 8.56.1.15 is the driver that shipped with Windows 7 RTM
+     */
+    APPEND_TO_DRIVER_BLOCKLIST(OperatingSystem::Windows, DeviceFamily::AtiAll,
+                               GfxDriverInfo::optionalFeatures,
+                               nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+                               DRIVER_LESS_THAN, V(8, 56, 1, 15),
+                               "FEATURE_FAILURE_AMD1", "8.56.1.15");
+
+    // Bug 1099252
+    APPEND_TO_DRIVER_BLOCKLIST2(OperatingSystem::Windows7, DeviceFamily::AtiAll,
+                                GfxDriverInfo::optionalFeatures,
+                                nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+                                DRIVER_EQUAL, V(8, 832, 0, 0),
+                                "FEATURE_FAILURE_BUG_1099252");
+
+    // Bug 1118695
+    APPEND_TO_DRIVER_BLOCKLIST2(OperatingSystem::Windows7, DeviceFamily::AtiAll,
+                                GfxDriverInfo::optionalFeatures,
+                                nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+                                DRIVER_EQUAL, V(8, 783, 2, 2000),
+                                "FEATURE_FAILURE_BUG_1118695");
+
+    // Bug 1587155
+    //
+    // There are a several reports of strange rendering corruptions with this
+    // driver version, with and without webrender. We weren't able to
+    // reproduce these problems, but the users were able to update their
+    // drivers and it went away. So just to be safe, let's blocklist all
+    // gpu use with this particular (very old) driver, restricted
+    // to Win10 since we only have reports from that platform.
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows10, DeviceFamily::AtiAll,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_EQUAL,
+        V(22, 19, 162, 4), "FEATURE_FAILURE_BUG_1587155");
+
+    // Bug 1829487 - Work around a gen6 driver bug that miscompiles shaders
+    // resulting
+    //               in black squares. Disabling shader optimization pass
+    //               appears to work around this for now.
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelSandyBridge,
+        nsIGfxInfo::FEATURE_WEBRENDER_OPTIMIZED_SHADERS,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_LESS_THAN,
+        GfxDriverInfo::allDriverVersions, "FEATURE_FAILURE_BUG_1829487");
+
+    // Bug 1198815
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(15, 200, 0, 0), V(15, 200, 1062, 1004), "FEATURE_FAILURE_BUG_1198815",
+        "15.200.0.0-15.200.1062.1004");
+
+    // Bug 1267970
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows10, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(15, 200, 0, 0), V(15, 301, 2301, 1002), "FEATURE_FAILURE_BUG_1267970",
+        "15.200.0.0-15.301.2301.1002");
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows10, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(16, 100, 0, 0), V(16, 300, 2311, 0), "FEATURE_FAILURE_BUG_1267970",
+        "16.100.0.0-16.300.2311.0");
+
+    /*
+     * Bug 783517 - crashes in AMD driver on Windows 8
+     */
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows8, DeviceFamily::AtiAll,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+        DRIVER_BETWEEN_INCLUSIVE_START, V(8, 982, 0, 0), V(8, 983, 0, 0),
+        "FEATURE_FAILURE_BUG_783517_AMD", "!= 8.982.*.*");
+
+    /*
+     *  Bug 1599981 - crashes in AMD driver on Windows 10
+     */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows10, DeviceFamily::RadeonCaicos,
+        nsIGfxInfo::FEATURE_DIRECT3D_11_LAYERS,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(15, 301, 1901, 0), "FEATURE_FAILURE_BUG_1599981");
+
+    /* OpenGL on any ATI/AMD hardware is discouraged
+     * See:
+     *  bug 619773 - WebGL: Crash with blue screen : "NMI: Parity Check / Memory
+     * Parity Error" bugs 584403, 584404, 620924 - crashes in atioglxx
+     *  + many complaints about incorrect rendering
+     */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_OPENGL_LAYERS, nsIGfxInfo::FEATURE_DISCOURAGED,
+        DRIVER_LESS_THAN, GfxDriverInfo::allDriverVersions,
+        "FEATURE_FAILURE_OGL_ATI_DIS");
+
+/*
+ * Intel entries
+ */
+
+/* The driver versions used here come from bug 594877. They might not
+ * be particularly relevant anymore.
+ */
+#define IMPLEMENT_INTEL_DRIVER_BLOCKLIST(winVer, devFamily, driverVer, ruleId) \
+  APPEND_TO_DRIVER_BLOCKLIST2(winVer, devFamily,                               \
+                              GfxDriverInfo::optionalFeatures,                 \
+                              nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,      \
+                              DRIVER_LESS_THAN, driverVer, ruleId)
+
+#define IMPLEMENT_INTEL_DRIVER_BLOCKLIST_D2D(winVer, devFamily, driverVer,     \
+                                             ruleId)                           \
+  APPEND_TO_DRIVER_BLOCKLIST2(winVer, devFamily, nsIGfxInfo::FEATURE_DIRECT2D, \
+                              nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,      \
+                              DRIVER_BUILD_ID_LESS_THAN, driverVer, ruleId)
+
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST_D2D(OperatingSystem::Windows7,
+                                         DeviceFamily::IntelGMA500, 2026,
+                                         "FEATURE_FAILURE_594877_7");
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST_D2D(
+        OperatingSystem::Windows7, DeviceFamily::IntelGMA900,
+        GfxDriverInfo::allDriverVersions, "FEATURE_FAILURE_594877_8");
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST_D2D(OperatingSystem::Windows7,
+                                         DeviceFamily::IntelGMA950, 1930,
+                                         "FEATURE_FAILURE_594877_9");
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST_D2D(OperatingSystem::Windows7,
+                                         DeviceFamily::IntelGMA3150, 2117,
+                                         "FEATURE_FAILURE_594877_10");
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST_D2D(OperatingSystem::Windows7,
+                                         DeviceFamily::IntelGMAX3000, 1930,
+                                         "FEATURE_FAILURE_594877_11");
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST_D2D(
+        OperatingSystem::Windows7, DeviceFamily::IntelHDGraphicsToSandyBridge,
+        2202, "FEATURE_FAILURE_594877_12");
+
+    /* Disable Direct2D on Intel GMAX4500 devices because of rendering
+     * corruption discovered in bug 1180379. These seems to affect even the most
+     * recent drivers. We're black listing all of the devices to be safe even
+     * though we've only confirmed the issue on the G45
+     */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelGMAX4500HD,
+        nsIGfxInfo::FEATURE_DIRECT2D, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, GfxDriverInfo::allDriverVersions,
+        "FEATURE_FAILURE_1180379");
+
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST(
+        OperatingSystem::Windows7, DeviceFamily::IntelGMA500, V(5, 0, 0, 2026),
+        "FEATURE_FAILURE_INTEL_16");
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST(
+        OperatingSystem::Windows7, DeviceFamily::IntelGMA900,
+        GfxDriverInfo::allDriverVersions, "FEATURE_FAILURE_INTEL_17");
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST(
+        OperatingSystem::Windows7, DeviceFamily::IntelGMA950,
+        V(8, 15, 10, 1930), "FEATURE_FAILURE_INTEL_18");
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST(
+        OperatingSystem::Windows7, DeviceFamily::IntelGMA3150,
+        V(8, 14, 10, 1972), "FEATURE_FAILURE_INTEL_19");
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST(
+        OperatingSystem::Windows7, DeviceFamily::IntelGMAX3000,
+        V(7, 15, 10, 1666), "FEATURE_FAILURE_INTEL_20");
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST(
+        OperatingSystem::Windows7, DeviceFamily::IntelGMAX4500HD,
+        V(7, 15, 10, 1666), "FEATURE_FAILURE_INTEL_21");
+    IMPLEMENT_INTEL_DRIVER_BLOCKLIST(
+        OperatingSystem::Windows7, DeviceFamily::IntelHDGraphicsToSandyBridge,
+        V(7, 15, 10, 1666), "FEATURE_FAILURE_INTEL_22");
+
+    // Bug 1074378
+    APPEND_TO_DRIVER_BLOCKLIST(
+        OperatingSystem::Windows7, DeviceFamily::IntelGMAX4500HD,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_EQUAL,
+        V(8, 15, 10, 1749), "FEATURE_FAILURE_BUG_1074378_1", "8.15.10.2342");
+    APPEND_TO_DRIVER_BLOCKLIST(
+        OperatingSystem::Windows7, DeviceFamily::IntelHDGraphicsToSandyBridge,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_EQUAL,
+        V(8, 15, 10, 1749), "FEATURE_FAILURE_BUG_1074378_2", "8.15.10.2342");
+
+    /* OpenGL on any Intel hardware is discouraged */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelAll,
+        nsIGfxInfo::FEATURE_OPENGL_LAYERS, nsIGfxInfo::FEATURE_DISCOURAGED,
+        DRIVER_LESS_THAN, GfxDriverInfo::allDriverVersions,
+        "FEATURE_FAILURE_INTEL_OGL_DIS");
+
+    /**
+     * Disable acceleration on Intel HD 3000 for graphics drivers
+     * <= 8.15.10.2321. See bug 1018278 and bug 1060736.
+     */
+    APPEND_TO_DRIVER_BLOCKLIST(OperatingSystem::Windows,
+                               DeviceFamily::IntelSandyBridge,
+                               GfxDriverInfo::optionalFeatures,
+                               nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+                               DRIVER_BUILD_ID_LESS_THAN_OR_EQUAL, 2321,
+                               "FEATURE_FAILURE_BUG_1018278", "X.X.X.2342");
+
+    /**
+     * Disable D2D on Win7 on Intel Haswell for graphics drivers build id <=
+     * 4578. See bug 1432610
+     */
+    APPEND_TO_DRIVER_BLOCKLIST2(OperatingSystem::Windows7,
+                                DeviceFamily::IntelHaswell,
+                                nsIGfxInfo::FEATURE_DIRECT2D,
+                                nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+                                DRIVER_BUILD_ID_LESS_THAN_OR_EQUAL, 4578,
+                                "FEATURE_FAILURE_BUG_1432610");
+    /**
+     * Disable VP8 HW decoding on Windows 8.1 on Intel Haswel and a certain
+     * driver version. See bug 1760464 comment 6 and bug 1761332.
+     */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows8_1, DeviceFamily::IntelHaswell,
+        nsIGfxInfo::FEATURE_VP8_HW_DECODE, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, GfxDriverInfo::allDriverVersions,
+        "FEATURE_FAILURE_BUG_1760464");
+
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows8_1, DeviceFamily::IntelAll,
+        nsIGfxInfo::FEATURE_VP8_HW_DECODE, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_EQUAL, V(10, 18, 14, 4264), "FEATURE_FAILURE_BUG_1761332");
+
+    /* Disable D2D on Win7 on Intel HD Graphics on driver <= 8.15.10.2302
+     * See bug 806786
+     */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows7, DeviceFamily::IntelMobileHDGraphics,
+        nsIGfxInfo::FEATURE_DIRECT2D,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN_OR_EQUAL,
+        V(8, 15, 10, 2302), "FEATURE_FAILURE_BUG_806786");
+
+    /* Disable D2D on Win8 on Intel HD Graphics on driver <= 8.15.10.2302
+     * See bug 804144 and 863683
+     */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows8, DeviceFamily::IntelMobileHDGraphics,
+        nsIGfxInfo::FEATURE_DIRECT2D,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN_OR_EQUAL,
+        V(8, 15, 10, 2302), "FEATURE_FAILURE_BUG_804144");
+
+    /* Disable D2D on Win7 on Intel HD Graphics on driver == 8.15.10.2418
+     * See bug 1433790
+     */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows7, DeviceFamily::IntelHDGraphicsToSandyBridge,
+        nsIGfxInfo::FEATURE_DIRECT2D,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_EQUAL,
+        V(8, 15, 10, 2418), "FEATURE_FAILURE_BUG_1433790");
+
+    /* Disable D3D11 layers on Intel G41 express graphics and Intel GM965, Intel
+     * X3100, for causing device resets. See bug 1116812.
+     */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::Bug1116812,
+        nsIGfxInfo::FEATURE_DIRECT3D_11_LAYERS,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_LESS_THAN,
+        GfxDriverInfo::allDriverVersions, "FEATURE_FAILURE_BUG_1116812");
+
+    /* Disable D3D11 layers on Intel GMA 3150 for failing to allocate a shared
+     * handle for textures. See bug 1207665. Additionally block D2D so we don't
+     * accidentally use WARP.
+     */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::Bug1207665,
+        nsIGfxInfo::FEATURE_DIRECT3D_11_LAYERS,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_LESS_THAN,
+        GfxDriverInfo::allDriverVersions, "FEATURE_FAILURE_BUG_1207665_1");
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::Bug1207665,
+        nsIGfxInfo::FEATURE_DIRECT2D, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, GfxDriverInfo::allDriverVersions,
+        "FEATURE_FAILURE_BUG_1207665_2");
+
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows10, DeviceFamily::QualcommAll,
+        nsIGfxInfo::FEATURE_DIRECT2D,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        GfxDriverInfo::allDriverVersions, "FEATURE_FAILURE_QUALCOMM");
+
+    // Bug 1548410. Disable hardware accelerated video decoding on
+    // Qualcomm drivers used on Windows on ARM64 which are known to
+    // cause BSOD's and output suprious green frames while decoding video.
+    // Bug 1592826 expands the blocklist.
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows10, DeviceFamily::QualcommAll,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN_OR_EQUAL,
+        V(25, 18, 10440, 0), "FEATURE_FAILURE_BUG_1592826");
+
+    /* Disable D2D on AMD Catalyst 14.4 until 14.6
+     * See bug 984488
+     */
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_DIRECT2D,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+        DRIVER_BETWEEN_INCLUSIVE_START, V(14, 1, 0, 0), V(14, 2, 0, 0),
+        "FEATURE_FAILURE_BUG_984488_1", "ATI Catalyst 14.6+");
+
+    /* Disable D3D9 layers on NVIDIA 6100/6150/6200 series due to glitches
+     * whilst scrolling. See bugs: 612007, 644787 & 645872.
+     */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::NvidiaBlockD3D9Layers,
+        nsIGfxInfo::FEATURE_DIRECT3D_9_LAYERS,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_LESS_THAN,
+        GfxDriverInfo::allDriverVersions, "FEATURE_FAILURE_BUG_612007");
+
+    /* Microsoft RemoteFX; blocked less than 6.2.0.0 */
+    APPEND_TO_DRIVER_BLOCKLIST(
+        OperatingSystem::Windows, DeviceFamily::MicrosoftAll,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(6, 2, 0, 0), "< 6.2.0.0", "FEATURE_FAILURE_REMOTE_FX");
+
+    /* Bug 1008759: Optimus (NVidia) crash.  Disable D2D on NV 310M. */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::Nvidia310M,
+        nsIGfxInfo::FEATURE_DIRECT2D, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, GfxDriverInfo::allDriverVersions,
+        "FEATURE_FAILURE_BUG_1008759");
+
+    /* Bug 1139503: DXVA crashes with ATI cards on windows 10. */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows10, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_EQUAL,
+        V(15, 200, 1006, 0), "FEATURE_FAILURE_BUG_1139503");
+
+    /* Bug 1213107: D3D9 crashes with ATI cards on Windows 7. */
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows7, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(8, 861, 0, 0), V(8, 862, 6, 5000), "FEATURE_FAILURE_BUG_1213107_1",
+        "Radeon driver > 8.862.6.5000");
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows7, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_WEBGL_ANGLE,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(8, 861, 0, 0), V(8, 862, 6, 5000), "FEATURE_FAILURE_BUG_1213107_2",
+        "Radeon driver > 8.862.6.5000");
+
+    /* This may not be needed at all */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows7, DeviceFamily::Bug1155608,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(8, 15, 10, 2869), "FEATURE_FAILURE_INTEL_W7_HW_DECODING");
+
+    /* Bug 1203199/1092166: DXVA startup crashes on some intel drivers. */
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows, DeviceFamily::IntelAll,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(9, 17, 10, 0), V(9, 17, 10, 2849), "FEATURE_FAILURE_BUG_1203199_1",
+        "Intel driver > 9.17.10.2849");
+
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::Nvidia8800GTS,
+        nsIGfxInfo::FEATURE_HARDWARE_VIDEO_DECODING,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_EQUAL,
+        V(9, 18, 13, 4052), "FEATURE_FAILURE_BUG_1203199_2");
+
+    /* Bug 1137716: XXX this should really check for the matching Intel piece as
+     * well. Unfortunately, we don't have the infrastructure to do that */
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE_GPU2(
+        OperatingSystem::Windows7, DeviceFamily::Bug1137716,
+        GfxDriverInfo::optionalFeatures,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(8, 17, 12, 5730), V(8, 17, 12, 6901), "FEATURE_FAILURE_BUG_1137716",
+        "Nvidia driver > 8.17.12.6901");
+
+    /* Bug 1336710: Crash in rx::Blit9::initialize. */
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::WindowsXP, DeviceFamily::IntelGMAX4500HD,
+        nsIGfxInfo::FEATURE_WEBGL_ANGLE, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, GfxDriverInfo::allDriverVersions,
+        "FEATURE_FAILURE_BUG_1336710");
+
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::WindowsXP, DeviceFamily::IntelHDGraphicsToSandyBridge,
+        nsIGfxInfo::FEATURE_WEBGL_ANGLE, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, GfxDriverInfo::allDriverVersions,
+        "FEATURE_FAILURE_BUG_1336710");
+
+    /* Bug 1304360: Graphical artifacts with D3D9 on Windows 7. */
+    APPEND_TO_DRIVER_BLOCKLIST2(OperatingSystem::Windows7,
+                                DeviceFamily::IntelGMAX3000,
+                                nsIGfxInfo::FEATURE_DIRECT3D_9_LAYERS,
+                                nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+                                DRIVER_BUILD_ID_LESS_THAN_OR_EQUAL, 1749,
+                                "FEATURE_FAILURE_INTEL_W7_D3D9_LAYERS");
+
+    /* Bug 1717519/1717911: Crashes while drawing with swgl.
+     * Reproducible but not investigated yet.*/
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows, DeviceFamily::IntelAll,
+        nsIGfxInfo::FEATURE_DIRECT3D_11_LAYERS,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(8, 15, 10, 2125), V(8, 15, 10, 2141), "FEATURE_FAILURE_BUG_1717911",
+        "Intel driver > 8.15.10.2141");
+
+#if defined(_M_X64)
+    if (DetectBrokenAVX()) {
+      APPEND_TO_DRIVER_BLOCKLIST2(
+          OperatingSystem::Windows7, DeviceFamily::IntelAll,
+          nsIGfxInfo::FEATURE_DIRECT3D_11_LAYERS,
+          nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+          GfxDriverInfo::allDriverVersions, "FEATURE_FAILURE_BUG_1403353");
+    }
+#endif
+
+    ////////////////////////////////////
+    // WebGL
+
+    // Older than 5-15-2016
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_WEBGL_OPENGL, nsIGfxInfo::FEATURE_DISCOURAGED,
+        DRIVER_LESS_THAN, V(16, 200, 1010, 1002), "WEBGL_NATIVE_GL_OLD_AMD");
+
+    // Older than 11-18-2015
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelAll,
+        nsIGfxInfo::FEATURE_WEBGL_OPENGL, nsIGfxInfo::FEATURE_DISCOURAGED,
+        DRIVER_BUILD_ID_LESS_THAN, 4331, "WEBGL_NATIVE_GL_OLD_INTEL");
+
+    // Older than 2-23-2016
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_WEBGL_OPENGL, nsIGfxInfo::FEATURE_DISCOURAGED,
+        DRIVER_LESS_THAN, V(10, 18, 13, 6200), "WEBGL_NATIVE_GL_OLD_NVIDIA");
+
+    ////////////////////////////////////
+    // FEATURE_DX_INTEROP2
+
+    // All AMD.
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::AtiAll,
+        nsIGfxInfo::FEATURE_DX_INTEROP2,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        GfxDriverInfo::allDriverVersions, "DX_INTEROP2_AMD_CRASH");
+
+    ////////////////////////////////////
+    // FEATURE_D3D11_KEYED_MUTEX
+
+    // bug 1359416
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelHDGraphicsToSandyBridge,
+        nsIGfxInfo::FEATURE_D3D11_KEYED_MUTEX,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_LESS_THAN,
+        GfxDriverInfo::allDriverVersions, "FEATURE_FAILURE_BUG_1359416");
+
+    // Bug 1447141, for causing device creation crashes.
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows7, DeviceFamily::Bug1447141,
+        GfxDriverInfo::optionalFeatures, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_EQUAL, V(15, 201, 2201, 0), "FEATURE_FAILURE_BUG_1447141_1");
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows7, DeviceFamily::Bug1447141,
+        GfxDriverInfo::optionalFeatures, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_EQUAL, V(15, 201, 1701, 0), "FEATURE_FAILURE_BUG_1447141_1");
+
+    // bug 1457758
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::NvidiaAll,
+        GfxDriverInfo::optionalFeatures, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_EQUAL, V(24, 21, 13, 9731), "FEATURE_FAILURE_BUG_1457758");
+
+    ////////////////////////////////////
+    // FEATURE_DX_NV12
+
+    // Bug 1437334
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelHDGraphicsToSandyBridge,
+        nsIGfxInfo::FEATURE_DX_NV12, nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+        DRIVER_BUILD_ID_LESS_THAN_OR_EQUAL, 4459,
+        "FEATURE_BLOCKED_DRIVER_VERSION");
+
+    ////////////////////////////////////
+    // FEATURE_DX_P010
+
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_DX_P010, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, GfxDriverInfo::allDriverVersions,
+        "FEATURE_UNQUALIFIED_P010_NVIDIA");
+
+    ////////////////////////////////////
+    // FEATURE_VIDEO_OVERLAY - ALLOWLIST
+#ifdef EARLY_BETA_OR_EARLIER
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::All,
+        nsIGfxInfo::FEATURE_VIDEO_OVERLAY, nsIGfxInfo::FEATURE_ALLOW_ALWAYS,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0), "FEATURE_ROLLOUT_ALL");
+#else
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelAll,
+        nsIGfxInfo::FEATURE_VIDEO_OVERLAY, nsIGfxInfo::FEATURE_ALLOW_ALWAYS,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0), "FEATURE_ROLLOUT_INTEL");
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_VIDEO_OVERLAY, nsIGfxInfo::FEATURE_ALLOW_ALWAYS,
+        DRIVER_COMPARISON_IGNORED, V(0, 0, 0, 0), "FEATURE_ROLLOUT_NVIDIA");
+#endif
+
+    ////////////////////////////////////
+    // FEATURE_HW_DECODED_VIDEO_ZERO_COPY
+
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows10, DeviceFamily::IntelSkylake,
+        nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(20, 19, 15, 4285), V(20, 19, 15, 4390), "FEATURE_FAILURE_BUG_1763280",
+        "Intel driver 20.19.15.*");
+
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows10, DeviceFamily::IntelSkylake,
+        nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(10, 18, 15, 4256), V(10, 18, 15, 4293), "FEATURE_FAILURE_BUG_1763280",
+        "Intel driver 10.18.15.*");
+
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows10, DeviceFamily::IntelKabyLake,
+        nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        GfxDriverInfo::allDriverVersions, "FEATURE_FAILURE_BUG_1802357");
+
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(21, 21, 13, 7576), "FEATURE_FAILURE_BUG_1767212");
+
+    APPEND_TO_DRIVER_BLOCKLIST2(OperatingSystem::Windows, DeviceFamily::AtiAll,
+                                nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY,
+                                nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+                                DRIVER_LESS_THAN, V(23, 20, 826, 5120),
+                                "FEATURE_FAILURE_BUG_1767212");
+
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::RadeonBlockZeroVideoCopy,
+        nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_LESS_THAN,
+        V(26, 20, 15000, 37), "FEATURE_FAILURE_BUG_1767212");
+
+    ////////////////////////////////////
+    // FEATURE_HW_DECODED_VIDEO_ZERO_COPY - ALLOWLIST
+
+    // XXX ZeroCopyNV12Texture is disabled with non-intel GPUs for now.
+    // See Bug 1798242
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelAll,
+        nsIGfxInfo::FEATURE_HW_DECODED_VIDEO_ZERO_COPY,
+        nsIGfxInfo::FEATURE_ALLOW_ALWAYS, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_ROLLOUT_ALL");
+
+    ////////////////////////////////////
+    // FEATURE_REUSE_DECODER_DEVICE
+
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows10, DeviceFamily::IntelSkylake,
+        nsIGfxInfo::FEATURE_REUSE_DECODER_DEVICE,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(20, 19, 15, 4285), V(20, 19, 15, 4390), "FEATURE_FAILURE_BUG_1833809",
+        "Intel driver 20.19.15.*");
+
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows10, DeviceFamily::IntelSkylake,
+        nsIGfxInfo::FEATURE_REUSE_DECODER_DEVICE,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(10, 18, 15, 4256), V(10, 18, 15, 4293), "FEATURE_FAILURE_BUG_1833809",
+        "Intel driver 10.18.15.*");
+
+    ////////////////////////////////////
+    // FEATURE_WEBRENDER
+    // Block 8.56.1.15/16
+    APPEND_TO_DRIVER_BLOCKLIST2(OperatingSystem::Windows, DeviceFamily::AtiAll,
+                                nsIGfxInfo::FEATURE_WEBRENDER,
+                                nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION,
+                                DRIVER_LESS_THAN_OR_EQUAL, V(8, 56, 1, 16),
+                                "CRASHY_DRIVERS_BUG_1678808");
+
+    // Shader compilation startup crashes with WebRender on Windows 7.
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows7, DeviceFamily::NvidiaAll,
+        nsIGfxInfo::FEATURE_WEBRENDER,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_INCLUSIVE,
+        V(8, 17, 12, 8019), V(8, 17, 12, 8026), "FEATURE_FAILURE_BUG_1709629",
+        "nVidia driver > 280.26");
+
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelWebRenderBlocked,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, GfxDriverInfo::allDriverVersions,
+        "INTEL_DEVICE_GEN5_OR_OLDER");
+
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::NvidiaWebRenderBlocked,
+        nsIGfxInfo::FEATURE_WEBRENDER, nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+        DRIVER_LESS_THAN, GfxDriverInfo::allDriverVersions, "EARLY_NVIDIA");
+
+    ////////////////////////////////////
+    // FEATURE_WEBRENDER_COMPOSITOR
+
+#ifndef EARLY_BETA_OR_EARLIER
+    // See also bug 1616874
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelAll,
+        nsIGfxInfo::FEATURE_WEBRENDER_COMPOSITOR,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_EQUAL, V(24, 20, 100, 6293),
+        "FEATURE_FAILURE_BUG_1602511");
+
+    APPEND_TO_DRIVER_BLOCKLIST2(OperatingSystem::Windows, DeviceFamily::AtiAll,
+                                nsIGfxInfo::FEATURE_WEBRENDER_COMPOSITOR,
+                                nsIGfxInfo::FEATURE_BLOCKED_DEVICE,
+                                DRIVER_LESS_THAN_OR_EQUAL, V(8, 17, 10, 1129),
+                                "FEATURE_FAILURE_CHROME_BUG_800950");
+#endif
+
+    // WebRender is unable to use scissored clears in some cases
+    APPEND_TO_DRIVER_BLOCKLIST2(
+        OperatingSystem::Windows, DeviceFamily::IntelAll,
+        nsIGfxInfo::FEATURE_WEBRENDER_SCISSORED_CACHE_CLEARS,
+        nsIGfxInfo::FEATURE_BLOCKED_DEVICE, DRIVER_COMPARISON_IGNORED,
+        V(0, 0, 0, 0), "FEATURE_FAILURE_BUG_1603515");
+
+    ////////////////////////////////////
+    // FEATURE_BACKDROP_FILTER
+
+    // Backdrop filter crashes the driver. See bug 1785366 and bug 1784093.
+    APPEND_TO_DRIVER_BLOCKLIST_RANGE(
+        OperatingSystem::Windows, DeviceFamily::IntelHDGraphicsToIvyBridge,
+        nsIGfxInfo::FEATURE_BACKDROP_FILTER,
+        nsIGfxInfo::FEATURE_BLOCKED_DRIVER_VERSION, DRIVER_BETWEEN_EXCLUSIVE,
+        V(8, 15, 10, 2879), V(10, 18, 10, 4425), "FEATURE_FAILURE_BUG_1785366",
+        "Intel driver >= 10.18.10.4425");
+  }
+  return *sDriverInfo;
+}
+
+OperatingSystem GfxInfo::GetOperatingSystem() {
+  return WindowsVersionToOperatingSystem(mWindowsVersion);
+}
+
+nsresult GfxInfo::GetFeatureStatusImpl(
+    int32_t aFeature, int32_t* aStatus, nsAString& aSuggestedDriverVersion,
+    const nsTArray<GfxDriverInfo>& aDriverInfo, nsACString& aFailureId,
+    OperatingSystem* aOS /* = nullptr */) {
+  AssertNotWin32kLockdown();
+
+  NS_ENSURE_ARG_POINTER(aStatus);
+  aSuggestedDriverVersion.SetIsVoid(true);
+  OperatingSystem os = WindowsVersionToOperatingSystem(mWindowsVersion);
+  *aStatus = nsIGfxInfo::FEATURE_STATUS_UNKNOWN;
+  if (aOS) *aOS = os;
+
+  if (sShutdownOccurred) {
+    return NS_OK;
+  }
+
+  // Don't evaluate special cases if we're checking the downloaded blocklist.
+  if (!aDriverInfo.Length()) {
+    nsAutoString adapterVendorID;
+    nsAutoString adapterDeviceID;
+    nsAutoString adapterDriverVersionString;
+    if (NS_FAILED(GetAdapterVendorID(adapterVendorID)) ||
+        NS_FAILED(GetAdapterDeviceID(adapterDeviceID)) ||
+        NS_FAILED(GetAdapterDriverVersion(adapterDriverVersionString))) {
+      if (OnlyAllowFeatureOnKnownConfig(aFeature)) {
+        aFailureId = "FEATURE_FAILURE_GET_ADAPTER";
+        *aStatus = FEATURE_BLOCKED_DEVICE;
+      } else {
+        *aStatus = FEATURE_STATUS_OK;
+      }
+      return NS_OK;
+    }
+
+    if (OnlyAllowFeatureOnKnownConfig(aFeature) &&
+        !adapterVendorID.Equals(
+            GfxDriverInfo::GetDeviceVendor(DeviceVendor::Intel),
+            nsCaseInsensitiveStringComparator) &&
+        !adapterVendorID.Equals(
+            GfxDriverInfo::GetDeviceVendor(DeviceVendor::NVIDIA),
+            nsCaseInsensitiveStringComparator) &&
+        !adapterVendorID.Equals(
+            GfxDriverInfo::GetDeviceVendor(DeviceVendor::ATI),
+            nsCaseInsensitiveStringComparator) &&
+        !adapterVendorID.Equals(
+            GfxDriverInfo::GetDeviceVendor(DeviceVendor::Microsoft),
+            nsCaseInsensitiveStringComparator) &&
+        !adapterVendorID.Equals(
+            GfxDriverInfo::GetDeviceVendor(DeviceVendor::Parallels),
+            nsCaseInsensitiveStringComparator) &&
+        !adapterVendorID.Equals(
+            GfxDriverInfo::GetDeviceVendor(DeviceVendor::Qualcomm),
+            nsCaseInsensitiveStringComparator) &&
+        // FIXME - these special hex values are currently used in xpcshell tests
+        // introduced by bug 625160 patch 8/8. Maybe these tests need to be
+        // adjusted now that we're only whitelisting intel/ati/nvidia.
+        !adapterVendorID.LowerCaseEqualsLiteral("0xabcd") &&
+        !adapterVendorID.LowerCaseEqualsLiteral("0xdcba") &&
+        !adapterVendorID.LowerCaseEqualsLiteral("0xabab") &&
+        !adapterVendorID.LowerCaseEqualsLiteral("0xdcdc")) {
+      if (adapterVendorID.Equals(
+              GfxDriverInfo::GetDeviceVendor(DeviceVendor::MicrosoftHyperV),
+              nsCaseInsensitiveStringComparator) ||
+          adapterVendorID.Equals(
+              GfxDriverInfo::GetDeviceVendor(DeviceVendor::VMWare),
+              nsCaseInsensitiveStringComparator) ||
+          adapterVendorID.Equals(
+              GfxDriverInfo::GetDeviceVendor(DeviceVendor::VirtualBox),
+              nsCaseInsensitiveStringComparator)) {
+        aFailureId = "FEATURE_FAILURE_VM_VENDOR";
+      } else if (adapterVendorID.Equals(GfxDriverInfo::GetDeviceVendor(
+                                            DeviceVendor::MicrosoftBasic),
+                                        nsCaseInsensitiveStringComparator)) {
+        aFailureId = "FEATURE_FAILURE_MICROSOFT_BASIC_VENDOR";
+      } else if (adapterVendorID.IsEmpty()) {
+        aFailureId = "FEATURE_FAILURE_EMPTY_DEVICE_VENDOR";
+      } else {
+        aFailureId = "FEATURE_FAILURE_UNKNOWN_DEVICE_VENDOR";
+      }
+      *aStatus = FEATURE_BLOCKED_DEVICE;
+      return NS_OK;
+    }
+
+    if (adapterDriverVersionString.Length() == 0) {
+      if (OnlyAllowFeatureOnKnownConfig(aFeature)) {
+        aFailureId = "FEATURE_FAILURE_EMPTY_DRIVER_VERSION";
+        *aStatus = FEATURE_BLOCKED_DRIVER_VERSION;
+      } else {
+        *aStatus = FEATURE_STATUS_OK;
+      }
+      return NS_OK;
+    }
+
+    uint64_t driverVersion;
+    if (!ParseDriverVersion(adapterDriverVersionString, &driverVersion)) {
+      if (OnlyAllowFeatureOnKnownConfig(aFeature)) {
+        aFailureId = "FEATURE_FAILURE_PARSE_DRIVER";
+        *aStatus = FEATURE_BLOCKED_DRIVER_VERSION;
+      } else {
+        *aStatus = FEATURE_STATUS_OK;
+      }
+      return NS_OK;
+    }
+  }
+
+  return GfxInfoBase::GetFeatureStatusImpl(
+      aFeature, aStatus, aSuggestedDriverVersion, aDriverInfo, aFailureId, &os);
+}
+
+void GfxInfo::DescribeFeatures(JSContext* aCx, JS::Handle<JSObject*> aObj) {
+  // Add the platform neutral features
+  GfxInfoBase::DescribeFeatures(aCx, aObj);
+
+  JS::Rooted<JSObject*> obj(aCx);
+
+  gfx::FeatureState& d3d11 = gfxConfig::GetFeature(Feature::D3D11_COMPOSITING);
+  if (!InitFeatureObject(aCx, aObj, "d3d11", d3d11, &obj)) {
+    return;
+  }
+  if (d3d11.GetValue() == gfx::FeatureStatus::Available) {
+    DeviceManagerDx* dm = DeviceManagerDx::Get();
+    JS::Rooted<JS::Value> val(aCx,
+                              JS::Int32Value(dm->GetCompositorFeatureLevel()));
+    JS_SetProperty(aCx, obj, "version", val);
+
+    val = JS::BooleanValue(dm->IsWARP());
+    JS_SetProperty(aCx, obj, "warp", val);
+
+    val = JS::BooleanValue(dm->TextureSharingWorks());
+    JS_SetProperty(aCx, obj, "textureSharing", val);
+
+    bool blocklisted = false;
+    if (nsCOMPtr<nsIGfxInfo> gfxInfo = components::GfxInfo::Service()) {
+      int32_t status;
+      nsCString discardFailureId;
+      if (SUCCEEDED(
+              gfxInfo->GetFeatureStatus(nsIGfxInfo::FEATURE_DIRECT3D_11_LAYERS,
+                                        discardFailureId, &status))) {
+        blocklisted = (status != nsIGfxInfo::FEATURE_STATUS_OK);
+      }
+    }
+
+    val = JS::BooleanValue(blocklisted);
+    JS_SetProperty(aCx, obj, "blocklisted", val);
+  }
+
+  gfx::FeatureState& d2d = gfxConfig::GetFeature(Feature::DIRECT2D);
+  if (!InitFeatureObject(aCx, aObj, "d2d", d2d, &obj)) {
+    return;
+  }
+  {
+    const char* version = "1.1";
+    JS::Rooted<JSString*> str(aCx, JS_NewStringCopyZ(aCx, version));
+    JS::Rooted<JS::Value> val(aCx, JS::StringValue(str));
+    JS_SetProperty(aCx, obj, "version", val);
+  }
+}
+
+#ifdef DEBUG
+
+// Implement nsIGfxInfoDebug
+
+NS_IMETHODIMP GfxInfo::SpoofVendorID(const nsAString& aVendorID) {
+  mAdapterVendorID[mActiveGPUIndex] = aVendorID;
+  return NS_OK;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofDeviceID(const nsAString& aDeviceID) {
+  mAdapterDeviceID[mActiveGPUIndex] = aDeviceID;
+  return NS_OK;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofDriverVersion(const nsAString& aDriverVersion) {
+  mDriverVersion[mActiveGPUIndex] = aDriverVersion;
+  return NS_OK;
+}
+
+NS_IMETHODIMP GfxInfo::SpoofOSVersion(uint32_t aVersion) {
+  mWindowsVersion = aVersion;
+  return NS_OK;
+}
+
+#endif
diff --git a/widget/windows/GfxInfo.h b/widget/windows/GfxInfo.h
new file mode 100644
index 0000000000..f2549afa4e
--- /dev/null
+++ b/widget/windows/GfxInfo.h
@@ -0,0 +1,105 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_WINDOWS_GFXINFO_H_
+#define WIDGET_WINDOWS_GFXINFO_H_
+
+#include "GfxInfoBase.h"
+
+namespace mozilla::widget {
+
+class GfxInfo : public GfxInfoBase {
+ public:
+  using GfxInfoBase::GetFeatureStatus;
+  using GfxInfoBase::GetFeatureSuggestedDriverVersion;
+
+  GfxInfo() = default;
+  nsresult Init() override;
+
+  // We only declare the subset of nsIGfxInfo that we actually implement. The
+  // rest is brought forward from GfxInfoBase.
+  NS_IMETHOD GetD2DEnabled(bool* aD2DEnabled) override;
+  NS_IMETHOD GetDWriteEnabled(bool* aDWriteEnabled) override;
+  NS_IMETHOD GetDWriteVersion(nsAString& aDwriteVersion) override;
+  NS_IMETHOD GetEmbeddedInFirefoxReality(
+      bool* aEmbeddedInFirefoxReality) override;
+  NS_IMETHOD GetHasBattery(bool* aHasBattery) override;
+  NS_IMETHOD GetCleartypeParameters(nsAString& aCleartypeParams) override;
+  NS_IMETHOD GetWindowProtocol(nsAString& aWindowProtocol) override;
+  NS_IMETHOD GetTestType(nsAString& aTestType) override;
+  NS_IMETHOD GetAdapterDescription(nsAString& aAdapterDescription) override;
+  NS_IMETHOD GetAdapterDriver(nsAString& aAdapterDriver) override;
+  NS_IMETHOD GetAdapterVendorID(nsAString& aAdapterVendorID) override;
+  NS_IMETHOD GetAdapterDeviceID(nsAString& aAdapterDeviceID) override;
+  NS_IMETHOD GetAdapterSubsysID(nsAString& aAdapterSubsysID) override;
+  NS_IMETHOD GetAdapterRAM(uint32_t* aAdapterRAM) override;
+  NS_IMETHOD GetAdapterDriverVendor(nsAString& aAdapterDriverVendor) override;
+  NS_IMETHOD GetAdapterDriverVersion(nsAString& aAdapterDriverVersion) override;
+  NS_IMETHOD GetAdapterDriverDate(nsAString& aAdapterDriverDate) override;
+  NS_IMETHOD GetAdapterDescription2(nsAString& aAdapterDescription) override;
+  NS_IMETHOD GetAdapterDriver2(nsAString& aAdapterDriver) override;
+  NS_IMETHOD GetAdapterVendorID2(nsAString& aAdapterVendorID) override;
+  NS_IMETHOD GetAdapterDeviceID2(nsAString& aAdapterDeviceID) override;
+  NS_IMETHOD GetAdapterSubsysID2(nsAString& aAdapterSubsysID) override;
+  NS_IMETHOD GetAdapterRAM2(uint32_t* aAdapterRAM) override;
+  NS_IMETHOD GetAdapterDriverVendor2(nsAString& aAdapterDriverVendor) override;
+  NS_IMETHOD GetAdapterDriverVersion2(
+      nsAString& aAdapterDriverVersion) override;
+  NS_IMETHOD GetAdapterDriverDate2(nsAString& aAdapterDriverDate) override;
+  NS_IMETHOD GetIsGPU2Active(bool* aIsGPU2Active) override;
+  NS_IMETHOD GetDrmRenderDevice(nsACString& aDrmRenderDevice) override;
+
+  uint32_t OperatingSystemVersion() override { return mWindowsVersion; }
+  uint32_t OperatingSystemBuild() override { return mWindowsBuildNumber; }
+
+#ifdef DEBUG
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIGFXINFODEBUG
+#endif
+
+ private:
+  ~GfxInfo() = default;
+
+  // Disallow copy/move
+  GfxInfo(const GfxInfo&) = delete;
+  GfxInfo& operator=(const GfxInfo&) = delete;
+  GfxInfo(GfxInfo&&) = delete;
+  GfxInfo& operator=(GfxInfo&&) = delete;
+
+  OperatingSystem GetOperatingSystem() override;
+
+  nsresult GetFeatureStatusImpl(int32_t aFeature, int32_t* aStatus,
+                                nsAString& aSuggestedDriverVersion,
+                                const nsTArray<GfxDriverInfo>& aDriverInfo,
+                                nsACString& aFailureId,
+                                OperatingSystem* aOS = nullptr) override;
+  const nsTArray<GfxDriverInfo>& GetGfxDriverInfo() override;
+
+  void DescribeFeatures(JSContext* cx, JS::Handle<JSObject*> aOut) override;
+
+  void AddCrashReportAnnotations();
+
+  nsString mDeviceString[2];
+  nsString mDeviceID[2];
+  nsString mDriverVersion[2];
+  nsString mDriverDate[2];
+  nsString mDeviceKey[2];
+  nsString mDeviceKeyDebug;
+  nsString mAdapterVendorID[2];
+  nsString mAdapterDeviceID[2];
+  nsString mAdapterSubsysID[2];
+  uint32_t mWindowsVersion = 0;
+  uint32_t mWindowsBuildNumber = 0;
+  uint32_t mActiveGPUIndex = 0;  // This must be 0 or 1
+  bool mHasDualGPU = false;
+  bool mHasDriverVersionMismatch = false;
+  bool mHasBattery = false;
+};
+
+}  // namespace mozilla::widget
+
+#endif  // WIDGET_WINDOWS_GFXINFO_H_
diff --git a/widget/windows/IEnumFE.cpp b/widget/windows/IEnumFE.cpp
new file mode 100644
index 0000000000..8fe7138609
--- /dev/null
+++ b/widget/windows/IEnumFE.cpp
@@ -0,0 +1,139 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "IEnumFE.h"
+#include "nsAlgorithm.h"
+#include <algorithm>
+
+CEnumFormatEtc::CEnumFormatEtc() : mRefCnt(0), mCurrentIdx(0) {}
+
+// Constructor used by Clone()
+CEnumFormatEtc::CEnumFormatEtc(nsTArray<FormatEtc>& aArray)
+    : mRefCnt(0), mCurrentIdx(0) {
+  // a deep copy, calls FormatEtc's copy constructor on each
+  mFormatList.AppendElements(aArray);
+}
+
+CEnumFormatEtc::~CEnumFormatEtc() {}
+
+/* IUnknown impl. */
+
+STDMETHODIMP
+CEnumFormatEtc::QueryInterface(REFIID riid, LPVOID* ppv) {
+  *ppv = nullptr;
+
+  if (IsEqualIID(riid, IID_IUnknown) || IsEqualIID(riid, IID_IEnumFORMATETC))
+    *ppv = (LPVOID)this;
+
+  if (*ppv == nullptr) return E_NOINTERFACE;
+
+  // AddRef any interface we'll return.
+  ((LPUNKNOWN)*ppv)->AddRef();
+  return S_OK;
+}
+
+STDMETHODIMP_(ULONG)
+CEnumFormatEtc::AddRef() {
+  ++mRefCnt;
+  NS_LOG_ADDREF(this, mRefCnt, "CEnumFormatEtc", sizeof(*this));
+  return mRefCnt;
+}
+
+STDMETHODIMP_(ULONG)
+CEnumFormatEtc::Release() {
+  uint32_t refReturn;
+
+  refReturn = --mRefCnt;
+  NS_LOG_RELEASE(this, mRefCnt, "CEnumFormatEtc");
+
+  if (mRefCnt == 0) delete this;
+
+  return refReturn;
+}
+
+/* IEnumFORMATETC impl. */
+
+STDMETHODIMP
+CEnumFormatEtc::Next(ULONG aMaxToFetch, FORMATETC* aResult,
+                     ULONG* aNumFetched) {
+  // If the method retrieves the number of items requested, the return
+  // value is S_OK. Otherwise, it is S_FALSE.
+
+  if (aNumFetched) *aNumFetched = 0;
+
+  // aNumFetched can be null if aMaxToFetch is 1
+  if (!aNumFetched && aMaxToFetch > 1) return S_FALSE;
+
+  if (!aResult) return S_FALSE;
+
+  // We're done walking the list
+  if (mCurrentIdx >= mFormatList.Length()) return S_FALSE;
+
+  uint32_t left = mFormatList.Length() - mCurrentIdx;
+
+  if (!aMaxToFetch) return S_FALSE;
+
+  uint32_t count = std::min(static_cast<uint32_t>(aMaxToFetch), left);
+
+  uint32_t idx = 0;
+  while (count > 0) {
+    // Copy out to aResult
+    mFormatList[mCurrentIdx++].CopyOut(&aResult[idx++]);
+    count--;
+  }
+
+  if (aNumFetched) *aNumFetched = idx;
+
+  return S_OK;
+}
+
+STDMETHODIMP
+CEnumFormatEtc::Skip(ULONG aSkipNum) {
+  // If the method skips the number of items requested, the return value is
+  // S_OK. Otherwise, it is S_FALSE.
+
+  if ((mCurrentIdx + aSkipNum) >= mFormatList.Length()) return S_FALSE;
+
+  mCurrentIdx += aSkipNum;
+
+  return S_OK;
+}
+
+STDMETHODIMP
+CEnumFormatEtc::Reset(void) {
+  mCurrentIdx = 0;
+  return S_OK;
+}
+
+STDMETHODIMP
+CEnumFormatEtc::Clone(LPENUMFORMATETC* aResult) {
+  // Must return a new IEnumFORMATETC interface with the same iterative state.
+
+  if (!aResult) return E_INVALIDARG;
+
+  CEnumFormatEtc* pEnumObj = new CEnumFormatEtc(mFormatList);
+
+  if (!pEnumObj) return E_OUTOFMEMORY;
+
+  pEnumObj->AddRef();
+  pEnumObj->SetIndex(mCurrentIdx);
+
+  *aResult = pEnumObj;
+
+  return S_OK;
+}
+
+/* utils */
+
+void CEnumFormatEtc::AddFormatEtc(LPFORMATETC aFormat) {
+  if (!aFormat) return;
+  FormatEtc* etc = mFormatList.AppendElement();
+  // Make a copy of aFormat
+  if (etc) etc->CopyIn(aFormat);
+}
+
+/* private */
+
+void CEnumFormatEtc::SetIndex(uint32_t aIdx) { mCurrentIdx = aIdx; }
diff --git a/widget/windows/IEnumFE.h b/widget/windows/IEnumFE.h
new file mode 100644
index 0000000000..b8cb6ad9d0
--- /dev/null
+++ b/widget/windows/IEnumFE.h
@@ -0,0 +1,88 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef IEnumeFE_h__
+#define IEnumeFE_h__
+
+/*
+ * CEnumFormatEtc - implements IEnumFORMATETC
+ */
+
+#include <ole2.h>
+
+#include "nsTArray.h"
+#include "mozilla/Attributes.h"
+
+// FORMATETC container
+class FormatEtc {
+ public:
+  FormatEtc() { memset(&mFormat, 0, sizeof(FORMATETC)); }
+  FormatEtc(const FormatEtc& copy) { CopyIn(&copy.mFormat); }
+  ~FormatEtc() {
+    if (mFormat.ptd) CoTaskMemFree(mFormat.ptd);
+  }
+
+  void CopyIn(const FORMATETC* aSrc) {
+    if (!aSrc) {
+      memset(&mFormat, 0, sizeof(FORMATETC));
+      return;
+    }
+    mFormat = *aSrc;
+    if (aSrc->ptd) {
+      mFormat.ptd = (DVTARGETDEVICE*)CoTaskMemAlloc(sizeof(DVTARGETDEVICE));
+      *(mFormat.ptd) = *(aSrc->ptd);
+    }
+  }
+
+  void CopyOut(LPFORMATETC aDest) {
+    if (!aDest) return;
+    *aDest = mFormat;
+    if (mFormat.ptd) {
+      aDest->ptd = (DVTARGETDEVICE*)CoTaskMemAlloc(sizeof(DVTARGETDEVICE));
+      *(aDest->ptd) = *(mFormat.ptd);
+    }
+  }
+
+ private:
+  FORMATETC mFormat;
+};
+
+/*
+ * CEnumFormatEtc is created within IDataObject::EnumFormatEtc. This object
+ * lives on its own, that is, QueryInterface only knows IUnknown and
+ * IEnumFormatEtc, nothing more.  We still use an outer unknown for reference
+ * counting, because as long as this enumerator lives, the data object should
+ * live, thereby keeping the application up.
+ */
+
+class CEnumFormatEtc final : public IEnumFORMATETC {
+ public:
+  explicit CEnumFormatEtc(nsTArray<FormatEtc>& aArray);
+  CEnumFormatEtc();
+  ~CEnumFormatEtc();
+
+  // IUnknown impl.
+  STDMETHODIMP QueryInterface(REFIID riid, LPVOID* ppv);
+  STDMETHODIMP_(ULONG) AddRef();
+  STDMETHODIMP_(ULONG) Release();
+
+  // IEnumFORMATETC impl.
+  STDMETHODIMP Next(ULONG aMaxToFetch, FORMATETC* aResult, ULONG* aNumFetched);
+  STDMETHODIMP Skip(ULONG aSkipNum);
+  STDMETHODIMP Reset();
+  STDMETHODIMP Clone(LPENUMFORMATETC* aResult);  // Addrefs
+
+  // Utils
+  void AddFormatEtc(LPFORMATETC aFormat);
+
+ private:
+  nsTArray<FormatEtc> mFormatList;  // Formats
+  ULONG mRefCnt;                    // Object reference count
+  ULONG mCurrentIdx;                // Current element
+
+  void SetIndex(uint32_t aIdx);
+};
+
+#endif  //_IENUMFE_H_
diff --git a/widget/windows/IMMHandler.cpp b/widget/windows/IMMHandler.cpp
new file mode 100644
index 0000000000..2f64f93922
--- /dev/null
+++ b/widget/windows/IMMHandler.cpp
@@ -0,0 +1,2408 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Logging.h"
+
+#include "IMMHandler.h"
+#include "nsWindow.h"
+#include "nsWindowDefs.h"
+#include "WinIMEHandler.h"
+#include "WinUtils.h"
+#include "KeyboardLayout.h"
+#include <algorithm>
+
+#include "mozilla/CheckedInt.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/ToString.h"
+
+#ifndef IME_PROP_ACCEPT_WIDE_VKEY
+#  define IME_PROP_ACCEPT_WIDE_VKEY 0x20
+#endif
+
+//-------------------------------------------------------------------------
+//
+// from
+// http://download.microsoft.com/download/6/0/9/60908e9e-d2c1-47db-98f6-216af76a235f/msime.h
+// The document for this has been removed from MSDN...
+//
+//-------------------------------------------------------------------------
+
+#define RWM_MOUSE TEXT("MSIMEMouseOperation")
+
+#define IMEMOUSE_NONE 0x00  // no mouse button was pushed
+#define IMEMOUSE_LDOWN 0x01
+#define IMEMOUSE_RDOWN 0x02
+#define IMEMOUSE_MDOWN 0x04
+#define IMEMOUSE_WUP 0x10    // wheel up
+#define IMEMOUSE_WDOWN 0x20  // wheel down
+
+// For collecting other people's log, tell `MOZ_LOG=IMEHandler:4,sync`
+// rather than `MOZ_LOG=IMEHandler:5,sync` since using `5` may create too
+// big file.
+// Therefore you shouldn't use `LogLevel::Verbose` for logging usual behavior.
+extern mozilla::LazyLogModule gIMELog;
+
+static const char* GetBoolName(bool aBool) { return aBool ? "true" : "false"; }
+
+static void HandleSeparator(nsACString& aDesc) {
+  if (!aDesc.IsEmpty()) {
+    aDesc.AppendLiteral(" | ");
+  }
+}
+
+class GetIMEGeneralPropertyName : public nsAutoCString {
+ public:
+  explicit GetIMEGeneralPropertyName(DWORD aFlags) {
+    if (!aFlags) {
+      AppendLiteral("no flags");
+      return;
+    }
+    if (aFlags & IME_PROP_AT_CARET) {
+      AppendLiteral("IME_PROP_AT_CARET");
+    }
+    if (aFlags & IME_PROP_SPECIAL_UI) {
+      HandleSeparator(*this);
+      AppendLiteral("IME_PROP_SPECIAL_UI");
+    }
+    if (aFlags & IME_PROP_CANDLIST_START_FROM_1) {
+      HandleSeparator(*this);
+      AppendLiteral("IME_PROP_CANDLIST_START_FROM_1");
+    }
+    if (aFlags & IME_PROP_UNICODE) {
+      HandleSeparator(*this);
+      AppendLiteral("IME_PROP_UNICODE");
+    }
+    if (aFlags & IME_PROP_COMPLETE_ON_UNSELECT) {
+      HandleSeparator(*this);
+      AppendLiteral("IME_PROP_COMPLETE_ON_UNSELECT");
+    }
+    if (aFlags & IME_PROP_ACCEPT_WIDE_VKEY) {
+      HandleSeparator(*this);
+      AppendLiteral("IME_PROP_ACCEPT_WIDE_VKEY");
+    }
+  }
+  virtual ~GetIMEGeneralPropertyName() {}
+};
+
+class GetIMEUIPropertyName : public nsAutoCString {
+ public:
+  explicit GetIMEUIPropertyName(DWORD aFlags) {
+    if (!aFlags) {
+      AppendLiteral("no flags");
+      return;
+    }
+    if (aFlags & UI_CAP_2700) {
+      AppendLiteral("UI_CAP_2700");
+    }
+    if (aFlags & UI_CAP_ROT90) {
+      HandleSeparator(*this);
+      AppendLiteral("UI_CAP_ROT90");
+    }
+    if (aFlags & UI_CAP_ROTANY) {
+      HandleSeparator(*this);
+      AppendLiteral("UI_CAP_ROTANY");
+    }
+  }
+  virtual ~GetIMEUIPropertyName() {}
+};
+
+class GetReconvertStringLog : public nsAutoCString {
+ public:
+  explicit GetReconvertStringLog(RECONVERTSTRING* aReconv) {
+    AssignLiteral("{ dwSize=");
+    AppendInt(static_cast<uint32_t>(aReconv->dwSize));
+    AppendLiteral(", dwVersion=");
+    AppendInt(static_cast<uint32_t>(aReconv->dwVersion));
+    AppendLiteral(", dwStrLen=");
+    AppendInt(static_cast<uint32_t>(aReconv->dwStrLen));
+    AppendLiteral(", dwStrOffset=");
+    AppendInt(static_cast<uint32_t>(aReconv->dwStrOffset));
+    AppendLiteral(", dwCompStrLen=");
+    AppendInt(static_cast<uint32_t>(aReconv->dwCompStrLen));
+    AppendLiteral(", dwCompStrOffset=");
+    AppendInt(static_cast<uint32_t>(aReconv->dwCompStrOffset));
+    AppendLiteral(", dwTargetStrLen=");
+    AppendInt(static_cast<uint32_t>(aReconv->dwTargetStrLen));
+    AppendLiteral(", dwTargetStrOffset=");
+    AppendInt(static_cast<uint32_t>(aReconv->dwTargetStrOffset));
+    AppendLiteral(", result str=\"");
+    if (aReconv->dwStrLen) {
+      char16_t* strStart = reinterpret_cast<char16_t*>(
+          reinterpret_cast<char*>(aReconv) + aReconv->dwStrOffset);
+      nsDependentString str(strStart, aReconv->dwStrLen);
+      Append(NS_ConvertUTF16toUTF8(str));
+    }
+    AppendLiteral("\" }");
+  }
+  virtual ~GetReconvertStringLog() {}
+};
+
+namespace mozilla {
+namespace widget {
+
+static IMMHandler* gIMMHandler = nullptr;
+
+/******************************************************************************
+ * IMEContext
+ ******************************************************************************/
+
+IMEContext::IMEContext(HWND aWnd) : mWnd(aWnd), mIMC(::ImmGetContext(aWnd)) {}
+
+IMEContext::IMEContext(nsWindow* aWindowBase)
+    : mWnd(aWindowBase->GetWindowHandle()),
+      mIMC(::ImmGetContext(aWindowBase->GetWindowHandle())) {}
+
+void IMEContext::Init(HWND aWnd) {
+  Clear();
+  mWnd = aWnd;
+  mIMC = ::ImmGetContext(mWnd);
+}
+
+void IMEContext::Init(nsWindow* aWindowBase) {
+  Init(aWindowBase->GetWindowHandle());
+}
+
+void IMEContext::Clear() {
+  if (mWnd && mIMC) {
+    ::ImmReleaseContext(mWnd, mIMC);
+  }
+  mWnd = nullptr;
+  mIMC = nullptr;
+}
+
+/******************************************************************************
+ * IMMHandler
+ ******************************************************************************/
+
+static UINT sWM_MSIME_MOUSE = 0;  // mouse message for MSIME 98/2000
+
+WritingMode IMMHandler::sWritingModeOfCompositionFont;
+nsString IMMHandler::sIMEName;
+UINT IMMHandler::sCodePage = 0;
+DWORD IMMHandler::sIMEProperty = 0;
+DWORD IMMHandler::sIMEUIProperty = 0;
+bool IMMHandler::sAssumeVerticalWritingModeNotSupported = false;
+bool IMMHandler::sHasFocus = false;
+
+#define IMPL_IS_IME_ACTIVE(aReadableName, aActualName) \
+  bool IMMHandler::Is##aReadableName##Active() {       \
+    return sIMEName.Equals(aActualName);               \
+  }
+
+IMPL_IS_IME_ACTIVE(ATOK2006, u"ATOK 2006")
+IMPL_IS_IME_ACTIVE(ATOK2007, u"ATOK 2007")
+IMPL_IS_IME_ACTIVE(ATOK2008, u"ATOK 2008")
+IMPL_IS_IME_ACTIVE(ATOK2009, u"ATOK 2009")
+IMPL_IS_IME_ACTIVE(ATOK2010, u"ATOK 2010")
+// NOTE: Even on Windows for en-US, the name of Google Japanese Input is
+//       written in Japanese.
+IMPL_IS_IME_ACTIVE(GoogleJapaneseInput,
+                   u"Google \x65E5\x672C\x8A9E\x5165\x529B "
+                   u"IMM32 \x30E2\x30B8\x30E5\x30FC\x30EB")
+IMPL_IS_IME_ACTIVE(Japanist2003, u"Japanist 2003")
+
+#undef IMPL_IS_IME_ACTIVE
+
+// static
+bool IMMHandler::IsActiveIMEInBlockList() {
+  if (sIMEName.IsEmpty()) {
+    return false;
+  }
+#ifdef _WIN64
+  // ATOK started to be TIP of TSF since 2011.  Older than it, i.e., ATOK 2010
+  // and earlier have a lot of problems even for daily use.  Perhaps, the
+  // reason is Win 8 has a lot of changes around IMM-IME support and TSF,
+  // and ATOK 2010 is released earlier than Win 8.
+  // ATOK 2006 crashes while converting a word with candidate window.
+  // ATOK 2007 doesn't paint and resize suggest window and candidate window
+  // correctly (showing white window or too big window).
+  // ATOK 2008 and ATOK 2009 crash when user just opens their open state.
+  // ATOK 2010 isn't installable newly on Win 7 or later, but we have a lot of
+  // crash reports.
+  if ((IsATOK2006Active() || IsATOK2007Active() || IsATOK2008Active() ||
+       IsATOK2009Active() || IsATOK2010Active())) {
+    return true;
+  }
+#endif  // #ifdef _WIN64
+  return false;
+}
+
+// static
+void IMMHandler::EnsureHandlerInstance() {
+  if (!gIMMHandler) {
+    gIMMHandler = new IMMHandler();
+  }
+}
+
+// static
+void IMMHandler::Initialize() {
+  if (!sWM_MSIME_MOUSE) {
+    sWM_MSIME_MOUSE = ::RegisterWindowMessage(RWM_MOUSE);
+  }
+  sAssumeVerticalWritingModeNotSupported = Preferences::GetBool(
+      "intl.imm.vertical_writing.always_assume_not_supported", false);
+  InitKeyboardLayout(nullptr, ::GetKeyboardLayout(0));
+}
+
+// static
+void IMMHandler::Terminate() {
+  if (!gIMMHandler) return;
+  delete gIMMHandler;
+  gIMMHandler = nullptr;
+}
+
+// static
+bool IMMHandler::IsComposingOnOurEditor() {
+  return gIMMHandler && gIMMHandler->mIsComposing;
+}
+
+// static
+bool IMMHandler::IsComposingWindow(nsWindow* aWindow) {
+  return gIMMHandler && gIMMHandler->mComposingWindow == aWindow;
+}
+
+// static
+bool IMMHandler::IsTopLevelWindowOfComposition(nsWindow* aWindow) {
+  if (!gIMMHandler || !gIMMHandler->mComposingWindow) {
+    return false;
+  }
+  HWND wnd = gIMMHandler->mComposingWindow->GetWindowHandle();
+  return WinUtils::GetTopLevelHWND(wnd, true) == aWindow->GetWindowHandle();
+}
+
+// static
+bool IMMHandler::ShouldDrawCompositionStringOurselves() {
+  // If current IME has special UI or its composition window should not
+  // positioned to caret position, we should now draw composition string
+  // ourselves.
+  return !(sIMEProperty & IME_PROP_SPECIAL_UI) &&
+         (sIMEProperty & IME_PROP_AT_CARET);
+}
+
+// static
+bool IMMHandler::IsVerticalWritingSupported() {
+  // Even if IME claims that they support vertical writing mode but it may not
+  // support vertical writing mode for its candidate window.
+  if (sAssumeVerticalWritingModeNotSupported) {
+    return false;
+  }
+  // Google Japanese Input doesn't support vertical writing mode.  We should
+  // return false if it's active IME.
+  if (IsGoogleJapaneseInputActive()) {
+    return false;
+  }
+  return !!(sIMEUIProperty & (UI_CAP_2700 | UI_CAP_ROT90 | UI_CAP_ROTANY));
+}
+
+// static
+void IMMHandler::InitKeyboardLayout(nsWindow* aWindow, HKL aKeyboardLayout) {
+  UINT IMENameLength = ::ImmGetDescriptionW(aKeyboardLayout, nullptr, 0);
+  if (IMENameLength) {
+    // Add room for the terminating null character
+    sIMEName.SetLength(++IMENameLength);
+    IMENameLength =
+        ::ImmGetDescriptionW(aKeyboardLayout, sIMEName.get(), IMENameLength);
+    // Adjust the length to ignore the terminating null character
+    sIMEName.SetLength(IMENameLength);
+  } else {
+    sIMEName.Truncate();
+  }
+
+  WORD langID = LOWORD(aKeyboardLayout);
+  ::GetLocaleInfoW(MAKELCID(langID, SORT_DEFAULT),
+                   LOCALE_IDEFAULTANSICODEPAGE | LOCALE_RETURN_NUMBER,
+                   (PWSTR)&sCodePage, sizeof(sCodePage) / sizeof(WCHAR));
+  sIMEProperty = ::ImmGetProperty(aKeyboardLayout, IGP_PROPERTY);
+  sIMEUIProperty = ::ImmGetProperty(aKeyboardLayout, IGP_UI);
+
+  // If active IME is a TIP of TSF, we cannot retrieve the name with IMM32 API.
+  // For hacking some bugs of some TIP, we should set an IME name from the
+  // pref.
+  if (sCodePage == 932 && sIMEName.IsEmpty()) {
+    Preferences::GetString("intl.imm.japanese.assume_active_tip_name_as",
+                           sIMEName);
+  }
+
+  // Whether the IME supports vertical writing mode might be changed or
+  // some IMEs may need specific font for their UI.  Therefore, we should
+  // update composition font forcibly here.
+  if (aWindow) {
+    MaybeAdjustCompositionFont(aWindow, sWritingModeOfCompositionFont, true);
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::InitKeyboardLayout, aKeyboardLayout=%p (\"%s\"), "
+           "sCodePage=%u, sIMEProperty=%s, sIMEUIProperty=%s",
+           aKeyboardLayout, NS_ConvertUTF16toUTF8(sIMEName).get(), sCodePage,
+           GetIMEGeneralPropertyName(sIMEProperty).get(),
+           GetIMEUIPropertyName(sIMEUIProperty).get()));
+}
+
+// static
+UINT IMMHandler::GetKeyboardCodePage() { return sCodePage; }
+
+// static
+IMENotificationRequests IMMHandler::GetIMENotificationRequests() {
+  return IMENotificationRequests(
+      IMENotificationRequests::NOTIFY_POSITION_CHANGE |
+      IMENotificationRequests::NOTIFY_MOUSE_BUTTON_EVENT_ON_CHAR);
+}
+
+// used for checking the lParam of WM_IME_COMPOSITION
+#define IS_COMPOSING_LPARAM(lParam) \
+  ((lParam) & (GCS_COMPSTR | GCS_COMPATTR | GCS_COMPCLAUSE | GCS_CURSORPOS))
+#define IS_COMMITTING_LPARAM(lParam) ((lParam) & GCS_RESULTSTR)
+// Some IMEs (e.g., the standard IME for Korean) don't have caret position,
+// then, we should not set caret position to compositionchange event.
+#define NO_IME_CARET -1
+
+IMMHandler::IMMHandler()
+    : mComposingWindow(nullptr),
+      mCursorPosition(NO_IME_CARET),
+      mCompositionStart(0),
+      mIsComposing(false) {
+  MOZ_LOG(gIMELog, LogLevel::Debug, ("IMMHandler::IMMHandler is created"));
+}
+
+IMMHandler::~IMMHandler() {
+  if (mIsComposing) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Error,
+        ("  IMMHandler::~IMMHandler, ERROR, the instance is still composing"));
+  }
+  MOZ_LOG(gIMELog, LogLevel::Debug, ("IMMHandler::IMMHandler is destroyed"));
+}
+
+nsresult IMMHandler::EnsureClauseArray(int32_t aCount) {
+  NS_ENSURE_ARG_MIN(aCount, 0);
+  mClauseArray.SetCapacity(aCount + 32);
+  return NS_OK;
+}
+
+nsresult IMMHandler::EnsureAttributeArray(int32_t aCount) {
+  NS_ENSURE_ARG_MIN(aCount, 0);
+  mAttributeArray.SetCapacity(aCount + 64);
+  return NS_OK;
+}
+
+// static
+void IMMHandler::CommitComposition(nsWindow* aWindow, bool aForce) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::CommitComposition, aForce=%s, aWindow=%p, hWnd=%p, "
+           "mComposingWindow=%p%s",
+           GetBoolName(aForce), aWindow, aWindow->GetWindowHandle(),
+           gIMMHandler ? gIMMHandler->mComposingWindow : nullptr,
+           gIMMHandler && gIMMHandler->mComposingWindow
+               ? IsComposingOnOurEditor() ? " (composing on editor)"
+                                          : " (composing on plug-in)"
+               : ""));
+  if (!aForce && !IsComposingWindow(aWindow)) {
+    return;
+  }
+
+  IMEContext context(aWindow);
+  bool associated = context.AssociateDefaultContext();
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("  IMMHandler::CommitComposition, associated=%s",
+           GetBoolName(associated)));
+
+  if (context.IsValid()) {
+    ::ImmNotifyIME(context.get(), NI_COMPOSITIONSTR, CPS_COMPLETE, 0);
+    ::ImmNotifyIME(context.get(), NI_COMPOSITIONSTR, CPS_CANCEL, 0);
+  }
+
+  if (associated) {
+    context.Disassociate();
+  }
+}
+
+// static
+void IMMHandler::CancelComposition(nsWindow* aWindow, bool aForce) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::CancelComposition, aForce=%s, aWindow=%p, hWnd=%p, "
+           "mComposingWindow=%p%s",
+           GetBoolName(aForce), aWindow, aWindow->GetWindowHandle(),
+           gIMMHandler ? gIMMHandler->mComposingWindow : nullptr,
+           gIMMHandler && gIMMHandler->mComposingWindow
+               ? IsComposingOnOurEditor() ? " (composing on editor)"
+                                          : " (composing on plug-in)"
+               : ""));
+  if (!aForce && !IsComposingWindow(aWindow)) {
+    return;
+  }
+
+  IMEContext context(aWindow);
+  bool associated = context.AssociateDefaultContext();
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("  IMMHandler::CancelComposition, associated=%s",
+           GetBoolName(associated)));
+
+  if (context.IsValid()) {
+    ::ImmNotifyIME(context.get(), NI_COMPOSITIONSTR, CPS_CANCEL, 0);
+  }
+
+  if (associated) {
+    context.Disassociate();
+  }
+}
+
+// static
+void IMMHandler::OnFocusChange(bool aFocus, nsWindow* aWindow) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::OnFocusChange(aFocus=%s, aWindow=%p), sHasFocus=%s, "
+           "IsComposingWindow(aWindow)=%s, aWindow->Destroyed()=%s",
+           GetBoolName(aFocus), aWindow, GetBoolName(sHasFocus),
+           GetBoolName(IsComposingWindow(aWindow)),
+           GetBoolName(aWindow->Destroyed())));
+
+  if (!aFocus) {
+    IMEHandler::MaybeDestroyNativeCaret();
+    if (IsComposingWindow(aWindow) && aWindow->Destroyed()) {
+      CancelComposition(aWindow);
+    }
+  }
+  if (gIMMHandler) {
+    gIMMHandler->mContentSelection.reset();
+  }
+  sHasFocus = aFocus;
+}
+
+// static
+void IMMHandler::OnUpdateComposition(nsWindow* aWindow) {
+  if (!gIMMHandler) {
+    return;
+  }
+
+  IMEContext context(aWindow);
+  gIMMHandler->SetIMERelatedWindowsPos(aWindow, context);
+}
+
+// static
+void IMMHandler::OnSelectionChange(nsWindow* aWindow,
+                                   const IMENotification& aIMENotification,
+                                   bool aIsIMMActive) {
+  if (!aIMENotification.mSelectionChangeData.mCausedByComposition &&
+      aIsIMMActive) {
+    MaybeAdjustCompositionFont(
+        aWindow, aIMENotification.mSelectionChangeData.GetWritingMode());
+  }
+  // MaybeAdjustCompositionFont() may create gIMMHandler.  So, check it
+  // after a call of MaybeAdjustCompositionFont().
+  if (gIMMHandler) {
+    gIMMHandler->mContentSelection =
+        Some(ContentSelection(aIMENotification.mSelectionChangeData));
+  }
+}
+
+// static
+void IMMHandler::MaybeAdjustCompositionFont(nsWindow* aWindow,
+                                            const WritingMode& aWritingMode,
+                                            bool aForceUpdate) {
+  switch (sCodePage) {
+    case 932:  // Japanese Shift-JIS
+    case 936:  // Simlified Chinese GBK
+    case 949:  // Korean
+    case 950:  // Traditional Chinese Big5
+      EnsureHandlerInstance();
+      break;
+    default:
+      // If there is no instance of nsIMM32Hander, we shouldn't waste footprint.
+      if (!gIMMHandler) {
+        return;
+      }
+  }
+
+  // Like Navi-Bar of ATOK, some IMEs may require proper composition font even
+  // before sending WM_IME_STARTCOMPOSITION.
+  IMEContext context(aWindow);
+  gIMMHandler->AdjustCompositionFont(aWindow, context, aWritingMode,
+                                     aForceUpdate);
+}
+
+// static
+bool IMMHandler::ProcessInputLangChangeMessage(nsWindow* aWindow, WPARAM wParam,
+                                               LPARAM lParam,
+                                               MSGResult& aResult) {
+  aResult.mResult = 0;
+  aResult.mConsumed = false;
+  // We don't need to create the instance of the handler here.
+  if (gIMMHandler) {
+    gIMMHandler->OnInputLangChange(aWindow, wParam, lParam, aResult);
+  }
+  InitKeyboardLayout(aWindow, reinterpret_cast<HKL>(lParam));
+  // We can release the instance here, because the instance may be never
+  // used. E.g., the new keyboard layout may not use IME, or it may use TSF.
+  Terminate();
+  // Don't return as "processed", the messages should be processed on nsWindow
+  // too.
+  return false;
+}
+
+// static
+bool IMMHandler::ProcessMessage(nsWindow* aWindow, UINT msg, WPARAM& wParam,
+                                LPARAM& lParam, MSGResult& aResult) {
+  // XXX We store the composing window in mComposingWindow.  If IME messages are
+  // sent to different window, we should commit the old transaction.  And also
+  // if the new window handle is not focused, probably, we should not start
+  // the composition, however, such case should not be, it's just bad scenario.
+
+  aResult.mResult = 0;
+  switch (msg) {
+    case WM_INPUTLANGCHANGE:
+      return ProcessInputLangChangeMessage(aWindow, wParam, lParam, aResult);
+    case WM_IME_STARTCOMPOSITION:
+      EnsureHandlerInstance();
+      return gIMMHandler->OnIMEStartComposition(aWindow, aResult);
+    case WM_IME_COMPOSITION:
+      EnsureHandlerInstance();
+      return gIMMHandler->OnIMEComposition(aWindow, wParam, lParam, aResult);
+    case WM_IME_ENDCOMPOSITION:
+      EnsureHandlerInstance();
+      return gIMMHandler->OnIMEEndComposition(aWindow, aResult);
+    case WM_IME_CHAR:
+      return OnIMEChar(aWindow, wParam, lParam, aResult);
+    case WM_IME_NOTIFY:
+      return OnIMENotify(aWindow, wParam, lParam, aResult);
+    case WM_IME_REQUEST:
+      EnsureHandlerInstance();
+      return gIMMHandler->OnIMERequest(aWindow, wParam, lParam, aResult);
+    case WM_IME_SELECT:
+      return OnIMESelect(aWindow, wParam, lParam, aResult);
+    case WM_IME_SETCONTEXT:
+      return OnIMESetContext(aWindow, wParam, lParam, aResult);
+    case WM_KEYDOWN:
+      return OnKeyDownEvent(aWindow, wParam, lParam, aResult);
+    case WM_CHAR:
+      if (!gIMMHandler) {
+        return false;
+      }
+      return gIMMHandler->OnChar(aWindow, wParam, lParam, aResult);
+    default:
+      return false;
+  };
+}
+
+/****************************************************************************
+ * message handlers
+ ****************************************************************************/
+
+void IMMHandler::OnInputLangChange(nsWindow* aWindow, WPARAM wParam,
+                                   LPARAM lParam, MSGResult& aResult) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::OnInputLangChange, hWnd=%p, wParam=%08zx, "
+           "lParam=%08" PRIxLPTR,
+           aWindow->GetWindowHandle(), wParam, lParam));
+
+  aWindow->NotifyIME(REQUEST_TO_COMMIT_COMPOSITION);
+  NS_ASSERTION(!mIsComposing, "ResetInputState failed");
+
+  if (mIsComposing) {
+    HandleEndComposition(aWindow);
+  }
+
+  aResult.mConsumed = false;
+}
+
+bool IMMHandler::OnIMEStartComposition(nsWindow* aWindow, MSGResult& aResult) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::OnIMEStartComposition, hWnd=%p, mIsComposing=%s",
+           aWindow->GetWindowHandle(), GetBoolName(mIsComposing)));
+  aResult.mConsumed = ShouldDrawCompositionStringOurselves();
+  if (mIsComposing) {
+    NS_WARNING("Composition has been already started");
+    return true;
+  }
+
+  IMEContext context(aWindow);
+  HandleStartComposition(aWindow, context);
+  return true;
+}
+
+bool IMMHandler::OnIMEComposition(nsWindow* aWindow, WPARAM wParam,
+                                  LPARAM lParam, MSGResult& aResult) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("IMMHandler::OnIMEComposition, hWnd=%p, lParam=%08" PRIxLPTR
+       ", mIsComposing=%s, "
+       "GCS_RESULTSTR=%s, GCS_COMPSTR=%s, GCS_COMPATTR=%s, GCS_COMPCLAUSE=%s, "
+       "GCS_CURSORPOS=%s,",
+       aWindow->GetWindowHandle(), lParam, GetBoolName(mIsComposing),
+       GetBoolName(lParam & GCS_RESULTSTR), GetBoolName(lParam & GCS_COMPSTR),
+       GetBoolName(lParam & GCS_COMPATTR), GetBoolName(lParam & GCS_COMPCLAUSE),
+       GetBoolName(lParam & GCS_CURSORPOS)));
+
+  IMEContext context(aWindow);
+  aResult.mConsumed = HandleComposition(aWindow, context, lParam);
+  return true;
+}
+
+bool IMMHandler::OnIMEEndComposition(nsWindow* aWindow, MSGResult& aResult) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::OnIMEEndComposition, hWnd=%p, mIsComposing=%s",
+           aWindow->GetWindowHandle(), GetBoolName(mIsComposing)));
+
+  aResult.mConsumed = ShouldDrawCompositionStringOurselves();
+  if (!mIsComposing) {
+    return true;
+  }
+
+  // Korean IME posts WM_IME_ENDCOMPOSITION first when we hit space during
+  // composition. Then, we should ignore the message and commit the composition
+  // string at following WM_IME_COMPOSITION.
+  MSG compositionMsg;
+  if (WinUtils::PeekMessage(&compositionMsg, aWindow->GetWindowHandle(),
+                            WM_IME_STARTCOMPOSITION, WM_IME_COMPOSITION,
+                            PM_NOREMOVE) &&
+      compositionMsg.message == WM_IME_COMPOSITION &&
+      IS_COMMITTING_LPARAM(compositionMsg.lParam)) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("  IMMHandler::OnIMEEndComposition, WM_IME_ENDCOMPOSITION is "
+             "followed by WM_IME_COMPOSITION, ignoring the message..."));
+    return true;
+  }
+
+  // Otherwise, e.g., ChangJie doesn't post WM_IME_COMPOSITION before
+  // WM_IME_ENDCOMPOSITION when composition string becomes empty.
+  // Then, we should dispatch a compositionupdate event, a compositionchange
+  // event and a compositionend event.
+  // XXX Shouldn't we dispatch the compositionchange event with actual or
+  //     latest composition string?
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("  IMMHandler::OnIMEEndComposition, mCompositionString=\"%s\"%s",
+           NS_ConvertUTF16toUTF8(mCompositionString).get(),
+           mCompositionString.IsEmpty() ? "" : ", but canceling it..."));
+
+  HandleEndComposition(aWindow, &EmptyString());
+
+  return true;
+}
+
+// static
+bool IMMHandler::OnIMEChar(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                           MSGResult& aResult) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::OnIMEChar, hWnd=%p, char=%08zx",
+           aWindow->GetWindowHandle(), wParam));
+
+  // We don't need to fire any compositionchange events from here. This method
+  // will be called when the composition string of the current IME is not drawn
+  // by us and some characters are committed. In that case, the committed
+  // string was processed in nsWindow::OnIMEComposition already.
+
+  // We need to consume the message so that Windows don't send two WM_CHAR msgs
+  aResult.mConsumed = true;
+  return true;
+}
+
+// static
+bool IMMHandler::OnIMECompositionFull(nsWindow* aWindow, MSGResult& aResult) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::OnIMECompositionFull, hWnd=%p",
+           aWindow->GetWindowHandle()));
+
+  // not implement yet
+  aResult.mConsumed = false;
+  return true;
+}
+
+// static
+bool IMMHandler::OnIMENotify(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                             MSGResult& aResult) {
+  switch (wParam) {
+    case IMN_CHANGECANDIDATE:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_CHANGECANDIDATE, "
+               "lParam=%08" PRIxLPTR,
+               aWindow->GetWindowHandle(), lParam));
+      break;
+    case IMN_CLOSECANDIDATE:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_CLOSECANDIDATE, "
+               "lParam=%08" PRIxLPTR,
+               aWindow->GetWindowHandle(), lParam));
+      break;
+    case IMN_CLOSESTATUSWINDOW:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_CLOSESTATUSWINDOW",
+               aWindow->GetWindowHandle()));
+      break;
+    case IMN_GUIDELINE:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_GUIDELINE",
+               aWindow->GetWindowHandle()));
+      break;
+    case IMN_OPENCANDIDATE:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_OPENCANDIDATE, "
+               "lParam=%08" PRIxLPTR,
+               aWindow->GetWindowHandle(), lParam));
+      break;
+    case IMN_OPENSTATUSWINDOW:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_OPENSTATUSWINDOW",
+               aWindow->GetWindowHandle()));
+      break;
+    case IMN_SETCANDIDATEPOS:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_SETCANDIDATEPOS, "
+               "lParam=%08" PRIxLPTR,
+               aWindow->GetWindowHandle(), lParam));
+      break;
+    case IMN_SETCOMPOSITIONFONT:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_SETCOMPOSITIONFONT",
+               aWindow->GetWindowHandle()));
+      break;
+    case IMN_SETCOMPOSITIONWINDOW:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_SETCOMPOSITIONWINDOW",
+               aWindow->GetWindowHandle()));
+      break;
+    case IMN_SETCONVERSIONMODE:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_SETCONVERSIONMODE",
+               aWindow->GetWindowHandle()));
+      break;
+    case IMN_SETOPENSTATUS:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_SETOPENSTATUS",
+               aWindow->GetWindowHandle()));
+      break;
+    case IMN_SETSENTENCEMODE:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_SETSENTENCEMODE",
+               aWindow->GetWindowHandle()));
+      break;
+    case IMN_SETSTATUSWINDOWPOS:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_SETSTATUSWINDOWPOS",
+               aWindow->GetWindowHandle()));
+      break;
+    case IMN_PRIVATE:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMENotify, hWnd=%p, IMN_PRIVATE",
+               aWindow->GetWindowHandle()));
+      break;
+  }
+
+  // not implement yet
+  aResult.mConsumed = false;
+  return true;
+}
+
+bool IMMHandler::OnIMERequest(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                              MSGResult& aResult) {
+  switch (wParam) {
+    case IMR_RECONVERTSTRING:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMERequest, hWnd=%p, IMR_RECONVERTSTRING",
+               aWindow->GetWindowHandle()));
+      aResult.mConsumed = HandleReconvert(aWindow, lParam, &aResult.mResult);
+      return true;
+    case IMR_QUERYCHARPOSITION:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMERequest, hWnd=%p, IMR_QUERYCHARPOSITION",
+               aWindow->GetWindowHandle()));
+      aResult.mConsumed =
+          HandleQueryCharPosition(aWindow, lParam, &aResult.mResult);
+      return true;
+    case IMR_DOCUMENTFEED:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMERequest, hWnd=%p, IMR_DOCUMENTFEED",
+               aWindow->GetWindowHandle()));
+      aResult.mConsumed = HandleDocumentFeed(aWindow, lParam, &aResult.mResult);
+      return true;
+    default:
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::OnIMERequest, hWnd=%p, wParam=%08zx",
+               aWindow->GetWindowHandle(), wParam));
+      aResult.mConsumed = false;
+      return true;
+  }
+}
+
+// static
+bool IMMHandler::OnIMESelect(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                             MSGResult& aResult) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("IMMHandler::OnIMESelect, hWnd=%p, wParam=%08zx, lParam=%08" PRIxLPTR,
+       aWindow->GetWindowHandle(), wParam, lParam));
+
+  // not implement yet
+  aResult.mConsumed = false;
+  return true;
+}
+
+// static
+bool IMMHandler::OnIMESetContext(nsWindow* aWindow, WPARAM wParam,
+                                 LPARAM lParam, MSGResult& aResult) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::OnIMESetContext, hWnd=%p, %s, lParam=%08" PRIxLPTR,
+           aWindow->GetWindowHandle(), wParam ? "Active" : "Deactive", lParam));
+
+  aResult.mConsumed = false;
+
+  // NOTE: If the aWindow is top level window of the composing window because
+  // when a window on deactive window gets focus, WM_IME_SETCONTEXT (wParam is
+  // TRUE) is sent to the top level window first.  After that,
+  // WM_IME_SETCONTEXT (wParam is FALSE) is sent to the top level window.
+  // Finally, WM_IME_SETCONTEXT (wParam is TRUE) is sent to the focused window.
+  // The top level window never becomes composing window, so, we can ignore
+  // the WM_IME_SETCONTEXT on the top level window.
+  if (IsTopLevelWindowOfComposition(aWindow)) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("  IMMHandler::OnIMESetContext, hWnd=%p is top level window",
+             aWindow->GetWindowHandle()));
+    return true;
+  }
+
+  // When IME context is activating on another window,
+  // we should commit the old composition on the old window.
+  bool cancelComposition = false;
+  if (wParam && gIMMHandler) {
+    cancelComposition = gIMMHandler->CommitCompositionOnPreviousWindow(aWindow);
+  }
+
+  if (wParam && (lParam & ISC_SHOWUICOMPOSITIONWINDOW) &&
+      ShouldDrawCompositionStringOurselves()) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("  IMMHandler::OnIMESetContext, ISC_SHOWUICOMPOSITIONWINDOW is "
+             "removed"));
+    lParam &= ~ISC_SHOWUICOMPOSITIONWINDOW;
+  }
+
+  // We should sent WM_IME_SETCONTEXT to the DefWndProc here because the
+  // ancestor windows shouldn't receive this message.  If they receive the
+  // message, we cannot know whether which window is the target of the message.
+  aResult.mResult = ::DefWindowProc(aWindow->GetWindowHandle(),
+                                    WM_IME_SETCONTEXT, wParam, lParam);
+
+  // Cancel composition on the new window if we committed our composition on
+  // another window.
+  if (cancelComposition) {
+    CancelComposition(aWindow, true);
+  }
+
+  aResult.mConsumed = true;
+  return true;
+}
+
+bool IMMHandler::OnChar(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                        MSGResult& aResult) {
+  // The return value must be same as aResult.mConsumed because only when we
+  // consume the message, the caller shouldn't do anything anymore but
+  // otherwise, the caller should handle the message.
+  aResult.mConsumed = false;
+  if (IsIMECharRecordsEmpty()) {
+    return aResult.mConsumed;
+  }
+  WPARAM recWParam;
+  LPARAM recLParam;
+  DequeueIMECharRecords(recWParam, recLParam);
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("IMMHandler::OnChar, aWindow=%p, wParam=%08zx, lParam=%08" PRIxLPTR ", "
+       "recorded: wParam=%08zx, lParam=%08" PRIxLPTR,
+       aWindow->GetWindowHandle(), wParam, lParam, recWParam, recLParam));
+  // If an unexpected char message comes, we should reset the records,
+  // of course, this shouldn't happen.
+  if (recWParam != wParam || recLParam != lParam) {
+    ResetIMECharRecords();
+    return aResult.mConsumed;
+  }
+  // Eat the char message which is caused by WM_IME_CHAR because we should
+  // have processed the IME messages, so, this message could be come from
+  // a windowless plug-in.
+  aResult.mConsumed = true;
+  return aResult.mConsumed;
+}
+
+/****************************************************************************
+ * others
+ ****************************************************************************/
+
+TextEventDispatcher* IMMHandler::GetTextEventDispatcherFor(nsWindow* aWindow) {
+  return aWindow == mComposingWindow && mDispatcher
+             ? mDispatcher.get()
+             : aWindow->GetTextEventDispatcher();
+}
+
+void IMMHandler::HandleStartComposition(nsWindow* aWindow,
+                                        const IMEContext& aContext) {
+  MOZ_ASSERT(!mIsComposing,
+             "HandleStartComposition is called but mIsComposing is TRUE");
+
+  const Maybe<ContentSelection>& contentSelection =
+      GetContentSelectionWithQueryIfNothing(aWindow);
+  if (contentSelection.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::HandleStartComposition, FAILED, due to "
+             "Selection::GetContentSelectionWithQueryIfNothing() failure"));
+    return;
+  }
+  if (!contentSelection->HasRange()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::HandleStartComposition, FAILED, due to "
+             "there is no selection"));
+    return;
+  }
+
+  AdjustCompositionFont(aWindow, aContext, contentSelection->WritingModeRef());
+
+  mCompositionStart = contentSelection->OffsetAndDataRef().StartOffset();
+  mCursorPosition = NO_IME_CARET;
+
+  RefPtr<TextEventDispatcher> dispatcher = GetTextEventDispatcherFor(aWindow);
+  nsresult rv = dispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::HandleStartComposition, FAILED due to "
+             "TextEventDispatcher::BeginNativeInputTransaction() failure"));
+    return;
+  }
+  WidgetEventTime eventTime = aWindow->CurrentMessageWidgetEventTime();
+  nsEventStatus status;
+  rv = dispatcher->StartComposition(status, &eventTime);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::HandleStartComposition, FAILED, due to "
+             "TextEventDispatcher::StartComposition() failure"));
+    return;
+  }
+
+  mIsComposing = true;
+  mComposingWindow = aWindow;
+  mDispatcher = dispatcher;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::HandleStartComposition, START composition, "
+           "mCompositionStart=%u",
+           mCompositionStart));
+}
+
+bool IMMHandler::HandleComposition(nsWindow* aWindow,
+                                   const IMEContext& aContext, LPARAM lParam) {
+  // for bug #60050
+  // MS-IME 95/97/98/2000 may send WM_IME_COMPOSITION with non-conversion
+  // mode before it send WM_IME_STARTCOMPOSITION.
+  // However, ATOK sends a WM_IME_COMPOSITION before WM_IME_STARTCOMPOSITION,
+  // and if we access ATOK via some APIs, ATOK will sometimes fail to
+  // initialize its state.  If WM_IME_STARTCOMPOSITION is already in the
+  // message queue, we should ignore the strange WM_IME_COMPOSITION message and
+  // skip to the next.  So, we should look for next composition message
+  // (WM_IME_STARTCOMPOSITION or WM_IME_ENDCOMPOSITION or WM_IME_COMPOSITION),
+  // and if it's WM_IME_STARTCOMPOSITION, and one more next composition message
+  // is WM_IME_COMPOSITION, current IME is ATOK, probably.  Otherwise, we
+  // should start composition forcibly.
+  if (!mIsComposing) {
+    MSG msg1, msg2;
+    HWND wnd = aWindow->GetWindowHandle();
+    if (WinUtils::PeekMessage(&msg1, wnd, WM_IME_STARTCOMPOSITION,
+                              WM_IME_COMPOSITION, PM_NOREMOVE) &&
+        msg1.message == WM_IME_STARTCOMPOSITION &&
+        WinUtils::PeekMessage(&msg2, wnd, WM_IME_ENDCOMPOSITION,
+                              WM_IME_COMPOSITION, PM_NOREMOVE) &&
+        msg2.message == WM_IME_COMPOSITION) {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("IMMHandler::HandleComposition, Ignores due to find a "
+               "WM_IME_STARTCOMPOSITION"));
+      return ShouldDrawCompositionStringOurselves();
+    }
+  }
+
+  bool startCompositionMessageHasBeenSent = mIsComposing;
+
+  //
+  // This catches a fixed result
+  //
+  if (IS_COMMITTING_LPARAM(lParam)) {
+    if (!mIsComposing) {
+      HandleStartComposition(aWindow, aContext);
+    }
+
+    GetCompositionString(aContext, GCS_RESULTSTR, mCompositionString);
+
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("IMMHandler::HandleComposition, GCS_RESULTSTR"));
+
+    HandleEndComposition(aWindow, &mCompositionString);
+
+    if (!IS_COMPOSING_LPARAM(lParam)) {
+      return ShouldDrawCompositionStringOurselves();
+    }
+  }
+
+  //
+  // This provides us with a composition string
+  //
+  if (!mIsComposing) {
+    HandleStartComposition(aWindow, aContext);
+  }
+
+  //--------------------------------------------------------
+  // 1. Get GCS_COMPSTR
+  //--------------------------------------------------------
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::HandleComposition, GCS_COMPSTR"));
+
+  nsAutoString previousCompositionString(mCompositionString);
+  GetCompositionString(aContext, GCS_COMPSTR, mCompositionString);
+
+  if (!IS_COMPOSING_LPARAM(lParam)) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Info,
+        ("  IMMHandler::HandleComposition, lParam doesn't indicate composing, "
+         "mCompositionString=\"%s\", previousCompositionString=\"%s\"",
+         NS_ConvertUTF16toUTF8(mCompositionString).get(),
+         NS_ConvertUTF16toUTF8(previousCompositionString).get()));
+
+    // If composition string isn't changed, we can trust the lParam.
+    // So, we need to do nothing.
+    if (previousCompositionString == mCompositionString) {
+      return ShouldDrawCompositionStringOurselves();
+    }
+
+    // IME may send WM_IME_COMPOSITION without composing lParam values
+    // when composition string becomes empty (e.g., using Backspace key).
+    // If composition string is empty, we should dispatch a compositionchange
+    // event with empty string and clear the clause information.
+    if (mCompositionString.IsEmpty()) {
+      mClauseArray.Clear();
+      mAttributeArray.Clear();
+      mCursorPosition = 0;
+      DispatchCompositionChangeEvent(aWindow, aContext);
+      return ShouldDrawCompositionStringOurselves();
+    }
+
+    // Otherwise, we cannot trust the lParam value.  We might need to
+    // dispatch compositionchange event with the latest composition string
+    // information.
+  }
+
+  // See https://bugzilla.mozilla.org/show_bug.cgi?id=296339
+  if (mCompositionString.IsEmpty() && !startCompositionMessageHasBeenSent) {
+    // In this case, maybe, the sender is MSPinYin. That sends *only*
+    // WM_IME_COMPOSITION with GCS_COMP* and GCS_RESULT* when
+    // user inputted the Chinese full stop. So, that doesn't send
+    // WM_IME_STARTCOMPOSITION and WM_IME_ENDCOMPOSITION.
+    // If WM_IME_STARTCOMPOSITION was not sent and the composition
+    // string is null (it indicates the composition transaction ended),
+    // WM_IME_ENDCOMPOSITION may not be sent. If so, we cannot run
+    // HandleEndComposition() in other place.
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("    IMMHandler::HandleComposition, Aborting GCS_COMPSTR"));
+    HandleEndComposition(aWindow);
+    return IS_COMMITTING_LPARAM(lParam);
+  }
+
+  //--------------------------------------------------------
+  // 2. Get GCS_COMPCLAUSE
+  //--------------------------------------------------------
+  long clauseArrayLength =
+      ::ImmGetCompositionStringW(aContext.get(), GCS_COMPCLAUSE, nullptr, 0);
+  clauseArrayLength /= sizeof(uint32_t);
+
+  if (clauseArrayLength > 0) {
+    nsresult rv = EnsureClauseArray(clauseArrayLength);
+    NS_ENSURE_SUCCESS(rv, false);
+
+    // Intelligent ABC IME (Simplified Chinese IME, the code page is 936)
+    // will crash in ImmGetCompositionStringW for GCS_COMPCLAUSE (bug 424663).
+    // See comment 35 of the bug for the detail. Therefore, we should use A
+    // API for it, however, we should not kill Unicode support on all IMEs.
+    bool useA_API = !(sIMEProperty & IME_PROP_UNICODE);
+
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("  IMMHandler::HandleComposition, GCS_COMPCLAUSE, useA_API=%s",
+             useA_API ? "TRUE" : "FALSE"));
+
+    long clauseArrayLength2 =
+        useA_API ? ::ImmGetCompositionStringA(
+                       aContext.get(), GCS_COMPCLAUSE, mClauseArray.Elements(),
+                       mClauseArray.Capacity() * sizeof(uint32_t))
+                 : ::ImmGetCompositionStringW(
+                       aContext.get(), GCS_COMPCLAUSE, mClauseArray.Elements(),
+                       mClauseArray.Capacity() * sizeof(uint32_t));
+    clauseArrayLength2 /= sizeof(uint32_t);
+
+    if (clauseArrayLength != clauseArrayLength2) {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("    IMMHandler::HandleComposition, GCS_COMPCLAUSE, "
+               "clauseArrayLength=%ld but clauseArrayLength2=%ld",
+               clauseArrayLength, clauseArrayLength2));
+      if (clauseArrayLength > clauseArrayLength2)
+        clauseArrayLength = clauseArrayLength2;
+    }
+
+    if (useA_API && clauseArrayLength > 0) {
+      // Convert each values of sIMECompClauseArray. The values mean offset of
+      // the clauses in ANSI string. But we need the values in Unicode string.
+      nsAutoCString compANSIStr;
+      if (ConvertToANSIString(mCompositionString, GetKeyboardCodePage(),
+                              compANSIStr)) {
+        uint32_t maxlen = compANSIStr.Length();
+        mClauseArray.SetLength(clauseArrayLength);
+        mClauseArray[0] = 0;  // first value must be 0
+        for (int32_t i = 1; i < clauseArrayLength; i++) {
+          uint32_t len = std::min(mClauseArray[i], maxlen);
+          mClauseArray[i] =
+              ::MultiByteToWideChar(GetKeyboardCodePage(), MB_PRECOMPOSED,
+                                    (LPCSTR)compANSIStr.get(), len, nullptr, 0);
+        }
+      }
+    }
+  }
+  // compClauseArrayLength may be negative. I.e., ImmGetCompositionStringW
+  // may return an error code.
+  mClauseArray.SetLength(std::max<long>(0, clauseArrayLength));
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("  IMMHandler::HandleComposition, GCS_COMPCLAUSE, mClauseLength=%zu",
+           mClauseArray.Length()));
+
+  //--------------------------------------------------------
+  // 3. Get GCS_COMPATTR
+  //--------------------------------------------------------
+  // This provides us with the attribute string necessary
+  // for doing hiliting
+  long attrArrayLength =
+      ::ImmGetCompositionStringW(aContext.get(), GCS_COMPATTR, nullptr, 0);
+  attrArrayLength /= sizeof(uint8_t);
+
+  if (attrArrayLength > 0) {
+    nsresult rv = EnsureAttributeArray(attrArrayLength);
+    NS_ENSURE_SUCCESS(rv, false);
+    attrArrayLength = ::ImmGetCompositionStringW(
+        aContext.get(), GCS_COMPATTR, mAttributeArray.Elements(),
+        mAttributeArray.Capacity() * sizeof(uint8_t));
+  }
+
+  // attrStrLen may be negative. I.e., ImmGetCompositionStringW may return an
+  // error code.
+  mAttributeArray.SetLength(std::max<long>(0, attrArrayLength));
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("  IMMHandler::HandleComposition, GCS_COMPATTR, mAttributeLength=%zu",
+       mAttributeArray.Length()));
+
+  //--------------------------------------------------------
+  // 4. Get GCS_CURSOPOS
+  //--------------------------------------------------------
+  // Some IMEs (e.g., the standard IME for Korean) don't have caret position.
+  if (lParam & GCS_CURSORPOS) {
+    mCursorPosition =
+        ::ImmGetCompositionStringW(aContext.get(), GCS_CURSORPOS, nullptr, 0);
+    if (mCursorPosition < 0) {
+      mCursorPosition = NO_IME_CARET;  // The result is error
+    }
+  } else {
+    mCursorPosition = NO_IME_CARET;
+  }
+
+  NS_ASSERTION(mCursorPosition <= (long)mCompositionString.Length(),
+               "illegal pos");
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("  IMMHandler::HandleComposition, GCS_CURSORPOS, mCursorPosition=%d",
+           mCursorPosition));
+
+  //--------------------------------------------------------
+  // 5. Send the compositionchange event
+  //--------------------------------------------------------
+  DispatchCompositionChangeEvent(aWindow, aContext);
+
+  return ShouldDrawCompositionStringOurselves();
+}
+
+void IMMHandler::HandleEndComposition(nsWindow* aWindow,
+                                      const nsAString* aCommitString) {
+  MOZ_ASSERT(mIsComposing,
+             "HandleEndComposition is called but mIsComposing is FALSE");
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::HandleEndComposition(aWindow=0x%p, aCommitString=0x%p "
+           "(\"%s\"))",
+           aWindow, aCommitString,
+           aCommitString ? NS_ConvertUTF16toUTF8(*aCommitString).get() : ""));
+
+  IMEHandler::MaybeDestroyNativeCaret();
+
+  RefPtr<TextEventDispatcher> dispatcher = GetTextEventDispatcherFor(aWindow);
+  nsresult rv = dispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::HandleEndComposition, FAILED due to "
+             "TextEventDispatcher::BeginNativeInputTransaction() failure"));
+    return;
+  }
+  WidgetEventTime eventTime = aWindow->CurrentMessageWidgetEventTime();
+  nsEventStatus status;
+  rv = dispatcher->CommitComposition(status, aCommitString, &eventTime);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::HandleStartComposition, FAILED, due to "
+             "TextEventDispatcher::CommitComposition() failure"));
+    return;
+  }
+  mIsComposing = false;
+  // XXX aWindow and mComposingWindow are always same??
+  mComposingWindow = nullptr;
+  mDispatcher = nullptr;
+}
+
+bool IMMHandler::HandleReconvert(nsWindow* aWindow, LPARAM lParam,
+                                 LRESULT* oResult) {
+  *oResult = 0;
+  RECONVERTSTRING* pReconv = reinterpret_cast<RECONVERTSTRING*>(lParam);
+
+  const Maybe<ContentSelection>& contentSelection =
+      GetContentSelectionWithQueryIfNothing(aWindow);
+  if (contentSelection.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("IMMHandler::HandleReconvert, FAILED, due to "
+             "Selection::GetContentSelectionWithQueryIfNothing() failure"));
+    return false;
+  }
+
+  const uint32_t len = contentSelection->HasRange()
+                           ? contentSelection->OffsetAndDataRef().Length()
+                           : 0u;
+  uint32_t needSize = sizeof(RECONVERTSTRING) + len * sizeof(WCHAR);
+
+  if (!pReconv) {
+    // Return need size to reconvert.
+    if (len == 0) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("IMMHandler::HandleReconvert, There are not selected text"));
+      return false;
+    }
+    *oResult = needSize;
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("IMMHandler::HandleReconvert, succeeded, result=%" PRIdLPTR,
+             *oResult));
+    return true;
+  }
+
+  if (pReconv->dwSize < needSize) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("IMMHandler::HandleReconvert, FAILED, pReconv->dwSize=%ld, "
+             "needSize=%u",
+             pReconv->dwSize, needSize));
+    return false;
+  }
+
+  *oResult = needSize;
+
+  // Fill reconvert struct
+  pReconv->dwVersion = 0;
+  pReconv->dwStrLen = len;
+  pReconv->dwStrOffset = sizeof(RECONVERTSTRING);
+  pReconv->dwCompStrLen = len;
+  pReconv->dwCompStrOffset = 0;
+  pReconv->dwTargetStrLen = len;
+  pReconv->dwTargetStrOffset = 0;
+
+  if (len) {
+    ::CopyMemory(reinterpret_cast<LPVOID>(lParam + sizeof(RECONVERTSTRING)),
+                 contentSelection->OffsetAndDataRef().DataRef().get(),
+                 len * sizeof(WCHAR));
+  }
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("IMMHandler::HandleReconvert, SUCCEEDED, pReconv=%s, result=%" PRIdLPTR,
+       GetReconvertStringLog(pReconv).get(), *oResult));
+
+  return true;
+}
+
+bool IMMHandler::HandleQueryCharPosition(nsWindow* aWindow, LPARAM lParam,
+                                         LRESULT* oResult) {
+  uint32_t len = mIsComposing ? mCompositionString.Length() : 0;
+  *oResult = false;
+  IMECHARPOSITION* pCharPosition = reinterpret_cast<IMECHARPOSITION*>(lParam);
+  if (!pCharPosition) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("IMMHandler::HandleQueryCharPosition, FAILED, due to "
+             "pCharPosition is null"));
+    return false;
+  }
+  if (pCharPosition->dwSize < sizeof(IMECHARPOSITION)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("IMMHandler::HandleReconvert, FAILED, pCharPosition->dwSize=%lu, "
+             "sizeof(IMECHARPOSITION)=%zu",
+             pCharPosition->dwSize, sizeof(IMECHARPOSITION)));
+    return false;
+  }
+  if (::GetFocus() != aWindow->GetWindowHandle()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("IMMHandler::HandleReconvert, FAILED, ::GetFocus()=%p, "
+             "OurWindowHandle=%p",
+             ::GetFocus(), aWindow->GetWindowHandle()));
+    return false;
+  }
+  if (pCharPosition->dwCharPos > len) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("IMMHandler::HandleQueryCharPosition, FAILED, "
+             "pCharPosition->dwCharPos=%ld, len=%u",
+             pCharPosition->dwCharPos, len));
+    return false;
+  }
+
+  LayoutDeviceIntRect r;
+  bool ret =
+      GetCharacterRectOfSelectedTextAt(aWindow, pCharPosition->dwCharPos, r);
+  NS_ENSURE_TRUE(ret, false);
+
+  LayoutDeviceIntRect screenRect;
+  // We always need top level window that is owner window of the popup window
+  // even if the content of the popup window has focus.
+  ResolveIMECaretPos(aWindow->GetTopLevelWindow(false), r, nullptr, screenRect);
+
+  // XXX This might need to check writing mode.  However, MSDN doesn't explain
+  //     how to set the values in vertical writing mode. Additionally, IME
+  //     doesn't work well with top-left of the character (this is explicitly
+  //     documented) and its horizontal width.  So, it might be better to set
+  //     top-right corner of the character and horizontal width, but we're not
+  //     sure if it doesn't cause any problems with a lot of IMEs...
+  pCharPosition->pt.x = screenRect.X();
+  pCharPosition->pt.y = screenRect.Y();
+
+  pCharPosition->cLineHeight = r.Height();
+
+  WidgetQueryContentEvent queryEditorRectEvent(true, eQueryEditorRect, aWindow);
+  aWindow->InitEvent(queryEditorRectEvent);
+  DispatchEvent(aWindow, queryEditorRectEvent);
+  if (NS_WARN_IF(queryEditorRectEvent.Failed())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::HandleQueryCharPosition, eQueryEditorRect failed"));
+    ::GetWindowRect(aWindow->GetWindowHandle(), &pCharPosition->rcDocument);
+  } else {
+    LayoutDeviceIntRect editorRectInWindow = queryEditorRectEvent.mReply->mRect;
+    nsWindow* window = !!queryEditorRectEvent.mReply->mFocusedWidget
+                           ? static_cast<nsWindow*>(
+                                 queryEditorRectEvent.mReply->mFocusedWidget)
+                           : aWindow;
+    LayoutDeviceIntRect editorRectInScreen;
+    ResolveIMECaretPos(window, editorRectInWindow, nullptr, editorRectInScreen);
+    ::SetRect(&pCharPosition->rcDocument, editorRectInScreen.X(),
+              editorRectInScreen.Y(), editorRectInScreen.XMost(),
+              editorRectInScreen.YMost());
+  }
+
+  *oResult = TRUE;
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("IMMHandler::HandleQueryCharPosition, SUCCEEDED, pCharPosition={ "
+       "pt={ x=%ld, y=%ld }, cLineHeight=%d, rcDocument={ left=%ld, top=%ld, "
+       "right=%ld, bottom=%ld } }",
+       pCharPosition->pt.x, pCharPosition->pt.y, pCharPosition->cLineHeight,
+       pCharPosition->rcDocument.left, pCharPosition->rcDocument.top,
+       pCharPosition->rcDocument.right, pCharPosition->rcDocument.bottom));
+  return true;
+}
+
+bool IMMHandler::HandleDocumentFeed(nsWindow* aWindow, LPARAM lParam,
+                                    LRESULT* oResult) {
+  *oResult = 0;
+  RECONVERTSTRING* pReconv = reinterpret_cast<RECONVERTSTRING*>(lParam);
+
+  LayoutDeviceIntPoint point(0, 0);
+
+  bool hasCompositionString =
+      mIsComposing && ShouldDrawCompositionStringOurselves();
+
+  int32_t targetOffset, targetLength;
+  if (!hasCompositionString) {
+    const Maybe<ContentSelection>& contentSelection =
+        GetContentSelectionWithQueryIfNothing(aWindow);
+    if (contentSelection.isNothing()) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("IMMHandler::HandleDocumentFeed, FAILED, due to "
+               "Selection::GetContentSelectionWithQueryIfNothing() failure"));
+      return false;
+    }
+    if (contentSelection->HasRange()) {
+      targetOffset = static_cast<int32_t>(
+          contentSelection->OffsetAndDataRef().StartOffset());
+      targetLength =
+          static_cast<int32_t>(contentSelection->OffsetAndDataRef().Length());
+    } else {
+      // If there is no selection range, let's return all text in the editor.
+      targetOffset = 0;
+      targetLength = INT32_MAX;
+    }
+  } else {
+    targetOffset = int32_t(mCompositionStart);
+    targetLength = int32_t(mCompositionString.Length());
+  }
+
+  // XXX nsString::Find and nsString::RFind take int32_t for offset, so,
+  //     we cannot support this message when the current offset is larger than
+  //     INT32_MAX.
+  if (targetOffset < 0 || targetLength < 0 || targetOffset + targetLength < 0) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("IMMHandler::HandleDocumentFeed, FAILED, "
+             "due to the selection is out of range"));
+    return false;
+  }
+
+  // Get all contents of the focused editor.
+  WidgetQueryContentEvent queryTextContentEvent(true, eQueryTextContent,
+                                                aWindow);
+  queryTextContentEvent.InitForQueryTextContent(0, UINT32_MAX);
+  aWindow->InitEvent(queryTextContentEvent, &point);
+  DispatchEvent(aWindow, queryTextContentEvent);
+  if (NS_WARN_IF(queryTextContentEvent.Failed())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("IMMHandler::HandleDocumentFeed, FAILED, "
+             "due to eQueryTextContent failure"));
+    return false;
+  }
+
+  nsAutoString str(queryTextContentEvent.mReply->DataRef());
+  if (targetOffset > static_cast<int32_t>(str.Length())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::HandleDocumentFeed, FAILED, "
+             "due to the caret offset is invalid"));
+    return false;
+  }
+
+  // Get the focused paragraph, we decide that it starts from the previous CRLF
+  // (or start of the editor) to the next one (or the end of the editor).
+  int32_t paragraphStart = 0;
+  if (targetOffset > 0) {
+    paragraphStart = Substring(str, 0, targetOffset).RFind(u"\n") + 1;
+  }
+  int32_t paragraphEnd = str.Find(u"\r", targetOffset + targetLength);
+  if (paragraphEnd < 0) {
+    paragraphEnd = str.Length();
+  }
+  nsDependentSubstring paragraph(str, paragraphStart,
+                                 paragraphEnd - paragraphStart);
+
+  uint32_t len = paragraph.Length();
+  uint32_t needSize = sizeof(RECONVERTSTRING) + len * sizeof(WCHAR);
+
+  if (!pReconv) {
+    *oResult = needSize;
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("IMMHandler::HandleDocumentFeed, succeeded, result=%" PRIdLPTR,
+             *oResult));
+    return true;
+  }
+
+  if (pReconv->dwSize < needSize) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("IMMHandler::HandleDocumentFeed, FAILED, "
+             "pReconv->dwSize=%ld, needSize=%u",
+             pReconv->dwSize, needSize));
+    return false;
+  }
+
+  // Fill reconvert struct
+  pReconv->dwVersion = 0;
+  pReconv->dwStrLen = len;
+  pReconv->dwStrOffset = sizeof(RECONVERTSTRING);
+  if (hasCompositionString) {
+    pReconv->dwCompStrLen = targetLength;
+    pReconv->dwCompStrOffset = (targetOffset - paragraphStart) * sizeof(WCHAR);
+    // Set composition target clause information
+    uint32_t offset, length;
+    if (!GetTargetClauseRange(&offset, &length)) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("IMMHandler::HandleDocumentFeed, FAILED, "
+               "due to IMMHandler::GetTargetClauseRange() failure"));
+      return false;
+    }
+    pReconv->dwTargetStrLen = length;
+    pReconv->dwTargetStrOffset = (offset - paragraphStart) * sizeof(WCHAR);
+  } else {
+    pReconv->dwTargetStrLen = targetLength;
+    pReconv->dwTargetStrOffset =
+        (targetOffset - paragraphStart) * sizeof(WCHAR);
+    // There is no composition string, so, the length is zero but we should
+    // set the cursor offset to the composition str offset.
+    pReconv->dwCompStrLen = 0;
+    pReconv->dwCompStrOffset = pReconv->dwTargetStrOffset;
+  }
+
+  *oResult = needSize;
+  ::CopyMemory(reinterpret_cast<LPVOID>(lParam + sizeof(RECONVERTSTRING)),
+               paragraph.BeginReading(), len * sizeof(WCHAR));
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::HandleDocumentFeed, SUCCEEDED, pReconv=%s, "
+           "result=%" PRIdLPTR,
+           GetReconvertStringLog(pReconv).get(), *oResult));
+
+  return true;
+}
+
+bool IMMHandler::CommitCompositionOnPreviousWindow(nsWindow* aWindow) {
+  if (!mComposingWindow || mComposingWindow == aWindow) {
+    return false;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::CommitCompositionOnPreviousWindow, mIsComposing=%s",
+           GetBoolName(mIsComposing)));
+
+  // If we have composition, we should dispatch composition events internally.
+  if (mIsComposing) {
+    IMEContext context(mComposingWindow);
+    NS_ASSERTION(context.IsValid(), "IME context must be valid");
+
+    HandleEndComposition(mComposingWindow);
+    return true;
+  }
+
+  return false;
+}
+
+static TextRangeType PlatformToNSAttr(uint8_t aAttr) {
+  switch (aAttr) {
+    case ATTR_INPUT_ERROR:
+    // case ATTR_FIXEDCONVERTED:
+    case ATTR_INPUT:
+      return TextRangeType::eRawClause;
+    case ATTR_CONVERTED:
+      return TextRangeType::eConvertedClause;
+    case ATTR_TARGET_NOTCONVERTED:
+      return TextRangeType::eSelectedRawClause;
+    case ATTR_TARGET_CONVERTED:
+      return TextRangeType::eSelectedClause;
+    default:
+      NS_ASSERTION(false, "unknown attribute");
+      return TextRangeType::eCaret;
+  }
+}
+
+// static
+void IMMHandler::DispatchEvent(nsWindow* aWindow, WidgetGUIEvent& aEvent) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("IMMHandler::DispatchEvent(aWindow=0x%p, aEvent={ mMessage=%s }, "
+       "aWindow->Destroyed()=%s",
+       aWindow, ToChar(aEvent.mMessage), GetBoolName(aWindow->Destroyed())));
+
+  if (aWindow->Destroyed()) {
+    return;
+  }
+
+  aWindow->DispatchWindowEvent(aEvent);
+}
+
+void IMMHandler::DispatchCompositionChangeEvent(nsWindow* aWindow,
+                                                const IMEContext& aContext) {
+  NS_ASSERTION(mIsComposing, "conflict state");
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::DispatchCompositionChangeEvent"));
+
+  // If we don't need to draw composition string ourselves, we don't need to
+  // fire compositionchange event during composing.
+  if (!ShouldDrawCompositionStringOurselves()) {
+    // But we need to adjust composition window pos and native caret pos, here.
+    SetIMERelatedWindowsPos(aWindow, aContext);
+    return;
+  }
+
+  RefPtr<nsWindow> kungFuDeathGrip(aWindow);
+  RefPtr<TextEventDispatcher> dispatcher = GetTextEventDispatcherFor(aWindow);
+  nsresult rv = dispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::DispatchCompositionChangeEvent, FAILED due to "
+             "TextEventDispatcher::BeginNativeInputTransaction() failure"));
+    return;
+  }
+
+  // NOTE: Calling SetIMERelatedWindowsPos() from this method will be failure
+  //       in e10s mode.  compositionchange event will notify this of
+  //       NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED, then
+  //       SetIMERelatedWindowsPos() will be called.
+
+  // XXX Sogou (Simplified Chinese IME) returns contradictory values:
+  //     The cursor position is actual cursor position. However, other values
+  //     (composition string and attributes) are empty.
+
+  if (mCompositionString.IsEmpty()) {
+    // Don't append clause information if composition string is empty.
+  } else if (mClauseArray.IsEmpty()) {
+    // Some IMEs don't return clause array information, then, we assume that
+    // all characters in the composition string are in one clause.
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("  IMMHandler::DispatchCompositionChangeEvent, "
+             "mClauseArray.Length()=0"));
+    rv = dispatcher->SetPendingComposition(mCompositionString, nullptr);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("  IMMHandler::DispatchCompositionChangeEvent, FAILED due to"
+               "TextEventDispatcher::SetPendingComposition() failure"));
+      return;
+    }
+  } else {
+    // iterate over the attributes
+    rv = dispatcher->SetPendingCompositionString(mCompositionString);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("  IMMHandler::DispatchCompositionChangeEvent, FAILED due to"
+               "TextEventDispatcher::SetPendingCompositionString() failure"));
+      return;
+    }
+    uint32_t lastOffset = 0;
+    for (uint32_t i = 0; i < mClauseArray.Length() - 1; i++) {
+      uint32_t current = mClauseArray[i + 1];
+      if (current > mCompositionString.Length()) {
+        MOZ_LOG(gIMELog, LogLevel::Info,
+                ("  IMMHandler::DispatchCompositionChangeEvent, "
+                 "mClauseArray[%u]=%u. "
+                 "This is larger than mCompositionString.Length()=%zu",
+                 i + 1, current, mCompositionString.Length()));
+        current = int32_t(mCompositionString.Length());
+      }
+
+      uint32_t length = current - lastOffset;
+      if (NS_WARN_IF(lastOffset >= mAttributeArray.Length())) {
+        MOZ_LOG(gIMELog, LogLevel::Error,
+                ("  IMMHandler::DispatchCompositionChangeEvent, FAILED due to "
+                 "invalid data of mClauseArray or mAttributeArray"));
+        return;
+      }
+      TextRangeType textRangeType =
+          PlatformToNSAttr(mAttributeArray[lastOffset]);
+      rv = dispatcher->AppendClauseToPendingComposition(length, textRangeType);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        MOZ_LOG(gIMELog, LogLevel::Error,
+                ("  IMMHandler::DispatchCompositionChangeEvent, FAILED due to"
+                 "TextEventDispatcher::AppendClauseToPendingComposition() "
+                 "failure"));
+        return;
+      }
+
+      lastOffset = current;
+
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("  IMMHandler::DispatchCompositionChangeEvent, index=%u, "
+               "rangeType=%s, range length=%u",
+               i, ToChar(textRangeType), length));
+    }
+  }
+
+  if (mCursorPosition == NO_IME_CARET) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("  IMMHandler::DispatchCompositionChangeEvent, no caret"));
+  } else {
+    uint32_t cursor = static_cast<uint32_t>(mCursorPosition);
+    if (cursor > mCompositionString.Length()) {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("  IMMHandler::CreateTextRangeArray, mCursorPosition=%d. "
+               "This is larger than mCompositionString.Length()=%zu",
+               mCursorPosition, mCompositionString.Length()));
+      cursor = mCompositionString.Length();
+    }
+
+    // If caret is in the target clause, the target clause will be painted as
+    // normal selection range.  Since caret shouldn't be in selection range on
+    // Windows, we shouldn't append caret range in such case.
+    const TextRangeArray* clauses = dispatcher->GetPendingCompositionClauses();
+    const TextRange* targetClause =
+        clauses ? clauses->GetTargetClause() : nullptr;
+    if (targetClause && cursor >= targetClause->mStartOffset &&
+        cursor <= targetClause->mEndOffset) {
+      // Forget the caret position specified by IME since Gecko's caret position
+      // will be at the end of composition string.
+      mCursorPosition = NO_IME_CARET;
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("  IMMHandler::CreateTextRangeArray, no caret due to it's in "
+               "the target clause, now, mCursorPosition is NO_IME_CARET"));
+    }
+
+    if (mCursorPosition != NO_IME_CARET) {
+      rv = dispatcher->SetCaretInPendingComposition(cursor, 0);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        MOZ_LOG(
+            gIMELog, LogLevel::Error,
+            ("  IMMHandler::DispatchCompositionChangeEvent, FAILED due to"
+             "TextEventDispatcher::SetCaretInPendingComposition() failure"));
+        return;
+      }
+    }
+  }
+
+  WidgetEventTime eventTime = aWindow->CurrentMessageWidgetEventTime();
+  nsEventStatus status;
+  rv = dispatcher->FlushPendingComposition(status, &eventTime);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::DispatchCompositionChangeEvent, FAILED due to"
+             "TextEventDispatcher::FlushPendingComposition() failure"));
+    return;
+  }
+}
+
+void IMMHandler::GetCompositionString(const IMEContext& aContext, DWORD aIndex,
+                                      nsAString& aCompositionString) const {
+  aCompositionString.Truncate();
+
+  // Retrieve the size of the required output buffer.
+  long lRtn = ::ImmGetCompositionStringW(aContext.get(), aIndex, nullptr, 0);
+  if (lRtn < 0 || !aCompositionString.SetLength((lRtn / sizeof(WCHAR)) + 1,
+                                                mozilla::fallible)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("IMMHandler::GetCompositionString, FAILED, due to OOM"));
+    return;  // Error or out of memory.
+  }
+
+  // Actually retrieve the composition string information.
+  lRtn = ::ImmGetCompositionStringW(aContext.get(), aIndex,
+                                    (LPVOID)aCompositionString.BeginWriting(),
+                                    lRtn + sizeof(WCHAR));
+  aCompositionString.SetLength(lRtn / sizeof(WCHAR));
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("IMMHandler::GetCompositionString, succeeded, aCompositionString=\"%s\"",
+       NS_ConvertUTF16toUTF8(aCompositionString).get()));
+}
+
+bool IMMHandler::GetTargetClauseRange(uint32_t* aOffset, uint32_t* aLength) {
+  NS_ENSURE_TRUE(aOffset, false);
+  NS_ENSURE_TRUE(mIsComposing, false);
+  NS_ENSURE_TRUE(ShouldDrawCompositionStringOurselves(), false);
+
+  bool found = false;
+  *aOffset = mCompositionStart;
+  for (uint32_t i = 0; i < mAttributeArray.Length(); i++) {
+    if (mAttributeArray[i] == ATTR_TARGET_NOTCONVERTED ||
+        mAttributeArray[i] == ATTR_TARGET_CONVERTED) {
+      *aOffset = mCompositionStart + i;
+      found = true;
+      break;
+    }
+  }
+
+  if (!aLength) {
+    return true;
+  }
+
+  if (!found) {
+    // The all composition string is targetted when there is no ATTR_TARGET_*
+    // clause. E.g., there is only ATTR_INPUT
+    *aLength = mCompositionString.Length();
+    return true;
+  }
+
+  uint32_t offsetInComposition = *aOffset - mCompositionStart;
+  *aLength = mCompositionString.Length() - offsetInComposition;
+  for (uint32_t i = offsetInComposition; i < mAttributeArray.Length(); i++) {
+    if (mAttributeArray[i] != ATTR_TARGET_NOTCONVERTED &&
+        mAttributeArray[i] != ATTR_TARGET_CONVERTED) {
+      *aLength = i - offsetInComposition;
+      break;
+    }
+  }
+  return true;
+}
+
+bool IMMHandler::ConvertToANSIString(const nsString& aStr, UINT aCodePage,
+                                     nsACString& aANSIStr) {
+  int len = ::WideCharToMultiByte(aCodePage, 0, (LPCWSTR)aStr.get(),
+                                  aStr.Length(), nullptr, 0, nullptr, nullptr);
+  NS_ENSURE_TRUE(len >= 0, false);
+
+  if (!aANSIStr.SetLength(len, mozilla::fallible)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("IMMHandler::ConvertToANSIString, FAILED, due to OOM"));
+    return false;
+  }
+  ::WideCharToMultiByte(aCodePage, 0, (LPCWSTR)aStr.get(), aStr.Length(),
+                        (LPSTR)aANSIStr.BeginWriting(), len, nullptr, nullptr);
+  return true;
+}
+
+bool IMMHandler::GetCharacterRectOfSelectedTextAt(
+    nsWindow* aWindow, uint32_t aOffset, LayoutDeviceIntRect& aCharRect,
+    WritingMode* aWritingMode) {
+  LayoutDeviceIntPoint point(0, 0);
+
+  const Maybe<ContentSelection>& contentSelection =
+      GetContentSelectionWithQueryIfNothing(aWindow);
+  if (contentSelection.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("IMMHandler::GetCharacterRectOfSelectedTextAt, FAILED, due to "
+             "Selection::GetContentSelectionWithQueryIfNothing() failure"));
+    return false;
+  }
+
+  // If there is neither a selection range nor composition string, cannot return
+  // character rect, of course.
+  if (!contentSelection->HasRange() && !mIsComposing) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("IMMHandler::GetCharacterRectOfSelectedTextAt, FAILED, due to "
+             "there is neither a selection range nor composition string"));
+    return false;
+  }
+
+  // If the offset is larger than the end of composition string or selected
+  // string, we should return false since such case must be a bug of the caller
+  // or the active IME.  If it's an IME's bug, we need to set targetLength to
+  // aOffset.
+  const uint32_t targetLength =
+      mIsComposing ? mCompositionString.Length()
+                   : contentSelection->OffsetAndDataRef().Length();
+  if (NS_WARN_IF(aOffset > targetLength)) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Error,
+        ("IMMHandler::GetCharacterRectOfSelectedTextAt, FAILED, due to "
+         "aOffset is too large (aOffset=%u, targetLength=%u, mIsComposing=%s)",
+         aOffset, targetLength, GetBoolName(mIsComposing)));
+    return false;
+  }
+
+  // If there is caret, we might be able to use caret rect.
+  uint32_t caretOffset = UINT32_MAX;
+  // There is a caret only when the normal selection is collapsed.
+  if (contentSelection.isNothing() ||
+      contentSelection->OffsetAndDataRef().IsDataEmpty()) {
+    if (mIsComposing) {
+      // If it's composing, mCursorPosition is the offset to caret in
+      // the composition string.
+      if (mCursorPosition != NO_IME_CARET) {
+        MOZ_ASSERT(mCursorPosition >= 0);
+        caretOffset = mCursorPosition;
+      } else if (!ShouldDrawCompositionStringOurselves() ||
+                 mCompositionString.IsEmpty()) {
+        // Otherwise, if there is no composition string, we should assume that
+        // there is a caret at the start of composition string.
+        caretOffset = 0;
+      }
+    } else {
+      // If there is no composition, the selection offset is the caret offset.
+      caretOffset = 0;
+    }
+  }
+
+  // If there is a caret and retrieving offset is same as the caret offset,
+  // we should use the caret rect.
+  if (aOffset != caretOffset) {
+    WidgetQueryContentEvent queryTextRectEvent(true, eQueryTextRect, aWindow);
+    WidgetQueryContentEvent::Options options;
+    options.mRelativeToInsertionPoint = true;
+    queryTextRectEvent.InitForQueryTextRect(aOffset, 1, options);
+    aWindow->InitEvent(queryTextRectEvent, &point);
+    DispatchEvent(aWindow, queryTextRectEvent);
+    if (queryTextRectEvent.Succeeded()) {
+      aCharRect = queryTextRectEvent.mReply->mRect;
+      if (aWritingMode) {
+        *aWritingMode = queryTextRectEvent.mReply->WritingModeRef();
+      }
+      MOZ_LOG(
+          gIMELog, LogLevel::Debug,
+          ("IMMHandler::GetCharacterRectOfSelectedTextAt, Succeeded, "
+           "aOffset=%u, aCharRect={ x: %d, y: %d, width: %d, height: %d }, "
+           "queryTextRectEvent={ mReply=%s }",
+           aOffset, aCharRect.X(), aCharRect.Y(), aCharRect.Width(),
+           aCharRect.Height(), ToString(queryTextRectEvent.mReply).c_str()));
+      return true;
+    }
+  }
+
+  return GetCaretRect(aWindow, aCharRect, aWritingMode);
+}
+
+bool IMMHandler::GetCaretRect(nsWindow* aWindow,
+                              LayoutDeviceIntRect& aCaretRect,
+                              WritingMode* aWritingMode) {
+  LayoutDeviceIntPoint point(0, 0);
+
+  WidgetQueryContentEvent queryCaretRectEvent(true, eQueryCaretRect, aWindow);
+  WidgetQueryContentEvent::Options options;
+  options.mRelativeToInsertionPoint = true;
+  queryCaretRectEvent.InitForQueryCaretRect(0, options);
+  aWindow->InitEvent(queryCaretRectEvent, &point);
+  DispatchEvent(aWindow, queryCaretRectEvent);
+  if (queryCaretRectEvent.Failed()) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Info,
+        ("IMMHandler::GetCaretRect, FAILED, due to eQueryCaretRect failure"));
+    return false;
+  }
+  aCaretRect = queryCaretRectEvent.mReply->mRect;
+  if (aWritingMode) {
+    *aWritingMode = queryCaretRectEvent.mReply->WritingModeRef();
+  }
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::GetCaretRect, SUCCEEDED, "
+           "aCaretRect={ x: %d, y: %d, width: %d, height: %d }, "
+           "queryCaretRectEvent={ mReply=%s }",
+           aCaretRect.X(), aCaretRect.Y(), aCaretRect.Width(),
+           aCaretRect.Height(), ToString(queryCaretRectEvent.mReply).c_str()));
+  return true;
+}
+
+bool IMMHandler::SetIMERelatedWindowsPos(nsWindow* aWindow,
+                                         const IMEContext& aContext) {
+  // Get first character rect of current a normal selected text or a composing
+  // string.
+  WritingMode writingMode;
+  LayoutDeviceIntRect firstSelectedCharRectRelativeToWindow;
+  bool ret = GetCharacterRectOfSelectedTextAt(
+      aWindow, 0, firstSelectedCharRectRelativeToWindow, &writingMode);
+  NS_ENSURE_TRUE(ret, false);
+  nsWindow* toplevelWindow = aWindow->GetTopLevelWindow(false);
+  LayoutDeviceIntRect firstSelectedCharRect;
+  ResolveIMECaretPos(toplevelWindow, firstSelectedCharRectRelativeToWindow,
+                     aWindow, firstSelectedCharRect);
+
+  // Set native caret size/position to our caret. Some IMEs honor it. E.g.,
+  // "Intelligent ABC" (Simplified Chinese) and "MS PinYin 3.0" (Simplified
+  // Chinese) on XP.  But if a11y module is handling native caret, we shouldn't
+  // touch it.
+  if (!IMEHandler::IsA11yHandlingNativeCaret()) {
+    LayoutDeviceIntRect caretRect(firstSelectedCharRect),
+        caretRectRelativeToWindow;
+    if (GetCaretRect(aWindow, caretRectRelativeToWindow)) {
+      ResolveIMECaretPos(toplevelWindow, caretRectRelativeToWindow, aWindow,
+                         caretRect);
+    } else {
+      NS_WARNING("failed to get caret rect");
+      caretRect.SetWidth(1);
+    }
+    IMEHandler::CreateNativeCaret(aWindow, caretRect);
+  }
+
+  if (ShouldDrawCompositionStringOurselves()) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("IMMHandler::SetIMERelatedWindowsPos, Set candidate window"));
+
+    // Get a rect of first character in current target in composition string.
+    LayoutDeviceIntRect firstTargetCharRect, lastTargetCharRect;
+    if (mIsComposing && !mCompositionString.IsEmpty()) {
+      // If there are no targetted selection, we should use it's first character
+      // rect instead.
+      uint32_t offset, length;
+      if (!GetTargetClauseRange(&offset, &length)) {
+        MOZ_LOG(gIMELog, LogLevel::Error,
+                ("  IMMHandler::SetIMERelatedWindowsPos, FAILED, due to "
+                 "GetTargetClauseRange() failure"));
+        return false;
+      }
+      ret =
+          GetCharacterRectOfSelectedTextAt(aWindow, offset - mCompositionStart,
+                                           firstTargetCharRect, &writingMode);
+      NS_ENSURE_TRUE(ret, false);
+      if (length) {
+        ret = GetCharacterRectOfSelectedTextAt(
+            aWindow, offset + length - 1 - mCompositionStart,
+            lastTargetCharRect);
+        NS_ENSURE_TRUE(ret, false);
+      } else {
+        lastTargetCharRect = firstTargetCharRect;
+      }
+    } else {
+      // If there are no composition string, we should use a first character
+      // rect.
+      ret = GetCharacterRectOfSelectedTextAt(aWindow, 0, firstTargetCharRect,
+                                             &writingMode);
+      NS_ENSURE_TRUE(ret, false);
+      lastTargetCharRect = firstTargetCharRect;
+    }
+    ResolveIMECaretPos(toplevelWindow, firstTargetCharRect, aWindow,
+                       firstTargetCharRect);
+    ResolveIMECaretPos(toplevelWindow, lastTargetCharRect, aWindow,
+                       lastTargetCharRect);
+    LayoutDeviceIntRect targetClauseRect;
+    targetClauseRect.UnionRect(firstTargetCharRect, lastTargetCharRect);
+
+    // Move the candidate window to proper position from the target clause as
+    // far as possible.
+    CANDIDATEFORM candForm;
+    candForm.dwIndex = 0;
+    if (!writingMode.IsVertical() || IsVerticalWritingSupported()) {
+      candForm.dwStyle = CFS_EXCLUDE;
+      // Candidate window shouldn't overlap the target clause in any writing
+      // mode.
+      candForm.rcArea.left = targetClauseRect.X();
+      candForm.rcArea.right = targetClauseRect.XMost();
+      candForm.rcArea.top = targetClauseRect.Y();
+      candForm.rcArea.bottom = targetClauseRect.YMost();
+      if (!writingMode.IsVertical()) {
+        // In horizontal layout, current point of interest should be top-left
+        // of the first character.
+        candForm.ptCurrentPos.x = firstTargetCharRect.X();
+        candForm.ptCurrentPos.y = firstTargetCharRect.Y();
+      } else if (writingMode.IsVerticalRL()) {
+        // In vertical layout (RL), candidate window should be positioned right
+        // side of target clause.  However, we don't set vertical writing font
+        // to the IME.  Therefore, the candidate window may be positioned
+        // bottom-left of target clause rect with these information.
+        candForm.ptCurrentPos.x = targetClauseRect.X();
+        candForm.ptCurrentPos.y = targetClauseRect.Y();
+      } else {
+        MOZ_ASSERT(writingMode.IsVerticalLR(), "Did we miss some causes?");
+        // In vertical layout (LR), candidate window should be poisitioned left
+        // side of target clause.  Although, we don't set vertical writing font
+        // to the IME, the candidate window may be positioned bottom-right of
+        // the target clause rect with these information.
+        candForm.ptCurrentPos.x = targetClauseRect.XMost();
+        candForm.ptCurrentPos.y = targetClauseRect.Y();
+      }
+    } else {
+      // If vertical writing is not supported by IME, let's set candidate
+      // window position to the bottom-left of the target clause because
+      // the position must be the safest position to prevent the candidate
+      // window to overlap with the target clause.
+      candForm.dwStyle = CFS_CANDIDATEPOS;
+      candForm.ptCurrentPos.x = targetClauseRect.X();
+      candForm.ptCurrentPos.y = targetClauseRect.YMost();
+    }
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("  IMMHandler::SetIMERelatedWindowsPos, Calling "
+             "ImmSetCandidateWindow()... ptCurrentPos={ x=%ld, y=%ld }, "
+             "rcArea={ left=%ld, top=%ld, right=%ld, bottom=%ld }, "
+             "writingMode=%s",
+             candForm.ptCurrentPos.x, candForm.ptCurrentPos.y,
+             candForm.rcArea.left, candForm.rcArea.top, candForm.rcArea.right,
+             candForm.rcArea.bottom, ToString(writingMode).c_str()));
+    ::ImmSetCandidateWindow(aContext.get(), &candForm);
+  } else {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("IMMHandler::SetIMERelatedWindowsPos, Set composition window"));
+
+    // Move the composition window to caret position (if selected some
+    // characters, we should use first character rect of them).
+    // And in this mode, IME adjusts the candidate window position
+    // automatically. So, we don't need to set it.
+    COMPOSITIONFORM compForm;
+    compForm.dwStyle = CFS_POINT;
+    compForm.ptCurrentPos.x = !writingMode.IsVerticalLR()
+                                  ? firstSelectedCharRect.X()
+                                  : firstSelectedCharRect.XMost();
+    compForm.ptCurrentPos.y = firstSelectedCharRect.Y();
+    ::ImmSetCompositionWindow(aContext.get(), &compForm);
+  }
+
+  return true;
+}
+
+void IMMHandler::ResolveIMECaretPos(nsIWidget* aReferenceWidget,
+                                    LayoutDeviceIntRect& aCursorRect,
+                                    nsIWidget* aNewOriginWidget,
+                                    LayoutDeviceIntRect& aOutRect) {
+  aOutRect = aCursorRect;
+
+  if (aReferenceWidget == aNewOriginWidget) return;
+
+  if (aReferenceWidget)
+    aOutRect.MoveBy(aReferenceWidget->WidgetToScreenOffset());
+
+  if (aNewOriginWidget)
+    aOutRect.MoveBy(-aNewOriginWidget->WidgetToScreenOffset());
+}
+
+static void SetHorizontalFontToLogFont(const nsAString& aFontFace,
+                                       LOGFONTW& aLogFont) {
+  aLogFont.lfEscapement = aLogFont.lfOrientation = 0;
+  if (NS_WARN_IF(aFontFace.Length() > LF_FACESIZE - 1)) {
+    memcpy(aLogFont.lfFaceName, L"System", sizeof(L"System"));
+    return;
+  }
+  memcpy(aLogFont.lfFaceName, aFontFace.BeginReading(),
+         aFontFace.Length() * sizeof(wchar_t));
+  aLogFont.lfFaceName[aFontFace.Length()] = 0;
+}
+
+static void SetVerticalFontToLogFont(const nsAString& aFontFace,
+                                     LOGFONTW& aLogFont) {
+  aLogFont.lfEscapement = aLogFont.lfOrientation = 2700;
+  if (NS_WARN_IF(aFontFace.Length() > LF_FACESIZE - 2)) {
+    memcpy(aLogFont.lfFaceName, L"@System", sizeof(L"@System"));
+    return;
+  }
+  aLogFont.lfFaceName[0] = '@';
+  memcpy(&aLogFont.lfFaceName[1], aFontFace.BeginReading(),
+         aFontFace.Length() * sizeof(wchar_t));
+  aLogFont.lfFaceName[aFontFace.Length() + 1] = 0;
+}
+
+void IMMHandler::AdjustCompositionFont(nsWindow* aWindow,
+                                       const IMEContext& aContext,
+                                       const WritingMode& aWritingMode,
+                                       bool aForceUpdate) {
+  // An instance of IMMHandler is destroyed when active IME is changed.
+  // Therefore, we need to store the information which are set to the IM
+  // context to static variables since IM context is never recreated.
+  static bool sCompositionFontsInitialized = false;
+  static nsString sCompositionFont;
+  static bool sCompositionFontPrefDone = false;
+  if (!sCompositionFontPrefDone) {
+    sCompositionFontPrefDone = true;
+    Preferences::GetString("intl.imm.composition_font", sCompositionFont);
+  }
+
+  // If composition font is customized by pref, we need to modify the
+  // composition font of the IME context at first time even if the writing mode
+  // is horizontal.
+  bool setCompositionFontForcibly =
+      aForceUpdate ||
+      (!sCompositionFontsInitialized && !sCompositionFont.IsEmpty());
+
+  static WritingMode sCurrentWritingMode;
+  static nsString sCurrentIMEName;
+  if (!setCompositionFontForcibly &&
+      sWritingModeOfCompositionFont == aWritingMode &&
+      sCurrentIMEName == sIMEName) {
+    // Nothing to do if writing mode isn't being changed.
+    return;
+  }
+
+  // Decide composition fonts for both horizontal writing mode and vertical
+  // writing mode.  If the font isn't specified by the pref, use default
+  // font which is already set to the IM context.  And also in vertical writing
+  // mode, insert '@' to the start of the font.
+  if (!sCompositionFontsInitialized) {
+    sCompositionFontsInitialized = true;
+    // sCompositionFontH must not start with '@' and its length is less than
+    // LF_FACESIZE since it needs to end with null terminating character.
+    if (sCompositionFont.IsEmpty() ||
+        sCompositionFont.Length() > LF_FACESIZE - 1 ||
+        sCompositionFont[0] == '@') {
+      LOGFONTW defaultLogFont;
+      if (NS_WARN_IF(
+              !::ImmGetCompositionFont(aContext.get(), &defaultLogFont))) {
+        MOZ_LOG(
+            gIMELog, LogLevel::Error,
+            ("  IMMHandler::AdjustCompositionFont, ::ImmGetCompositionFont() "
+             "failed"));
+        sCompositionFont.AssignLiteral("System");
+      } else {
+        // The font face is typically, "System".
+        sCompositionFont.Assign(defaultLogFont.lfFaceName);
+      }
+    }
+
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("  IMMHandler::AdjustCompositionFont, sCompositionFont=\"%s\" is "
+             "initialized",
+             NS_ConvertUTF16toUTF8(sCompositionFont).get()));
+  }
+
+  static nsString sCompositionFontForJapanist2003;
+  if (IsJapanist2003Active() && sCompositionFontForJapanist2003.IsEmpty()) {
+    const char* kCompositionFontForJapanist2003 =
+        "intl.imm.composition_font.japanist_2003";
+    Preferences::GetString(kCompositionFontForJapanist2003,
+                           sCompositionFontForJapanist2003);
+    // If the font name is not specified properly, let's use
+    // "MS PGothic" instead.
+    if (sCompositionFontForJapanist2003.IsEmpty() ||
+        sCompositionFontForJapanist2003.Length() > LF_FACESIZE - 2 ||
+        sCompositionFontForJapanist2003[0] == '@') {
+      sCompositionFontForJapanist2003.AssignLiteral("MS PGothic");
+    }
+  }
+
+  sWritingModeOfCompositionFont = aWritingMode;
+  sCurrentIMEName = sIMEName;
+
+  LOGFONTW logFont;
+  memset(&logFont, 0, sizeof(logFont));
+  if (!::ImmGetCompositionFont(aContext.get(), &logFont)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::AdjustCompositionFont, ::ImmGetCompositionFont() "
+             "failed"));
+    logFont.lfFaceName[0] = 0;
+  }
+  // Need to reset some information which should be recomputed with new font.
+  logFont.lfWidth = 0;
+  logFont.lfWeight = FW_DONTCARE;
+  logFont.lfOutPrecision = OUT_DEFAULT_PRECIS;
+  logFont.lfClipPrecision = CLIP_DEFAULT_PRECIS;
+  logFont.lfPitchAndFamily = DEFAULT_PITCH;
+
+  if (aWritingMode.IsVertical() && IsVerticalWritingSupported()) {
+    SetVerticalFontToLogFont(IsJapanist2003Active()
+                                 ? sCompositionFontForJapanist2003
+                                 : sCompositionFont,
+                             logFont);
+  } else {
+    SetHorizontalFontToLogFont(IsJapanist2003Active()
+                                   ? sCompositionFontForJapanist2003
+                                   : sCompositionFont,
+                               logFont);
+  }
+  MOZ_LOG(gIMELog, LogLevel::Warning,
+          ("  IMMHandler::AdjustCompositionFont, calling "
+           "::ImmSetCompositionFont(\"%s\")",
+           NS_ConvertUTF16toUTF8(nsDependentString(logFont.lfFaceName)).get()));
+  ::ImmSetCompositionFontW(aContext.get(), &logFont);
+}
+
+// static
+nsresult IMMHandler::OnMouseButtonEvent(
+    nsWindow* aWindow, const IMENotification& aIMENotification) {
+  // We don't need to create the instance of the handler here.
+  if (!gIMMHandler) {
+    return NS_OK;
+  }
+
+  if (!sWM_MSIME_MOUSE || !IsComposingOnOurEditor() ||
+      !ShouldDrawCompositionStringOurselves()) {
+    return NS_OK;
+  }
+
+  // We need to handle only mousedown event.
+  if (aIMENotification.mMouseButtonEventData.mEventMessage != eMouseDown) {
+    return NS_OK;
+  }
+
+  // If the character under the cursor is not in the composition string,
+  // we don't need to notify IME of it.
+  uint32_t compositionStart = gIMMHandler->mCompositionStart;
+  uint32_t compositionEnd =
+      compositionStart + gIMMHandler->mCompositionString.Length();
+  if (aIMENotification.mMouseButtonEventData.mOffset < compositionStart ||
+      aIMENotification.mMouseButtonEventData.mOffset >= compositionEnd) {
+    return NS_OK;
+  }
+
+  BYTE button;
+  switch (aIMENotification.mMouseButtonEventData.mButton) {
+    case MouseButton::ePrimary:
+      button = IMEMOUSE_LDOWN;
+      break;
+    case MouseButton::eMiddle:
+      button = IMEMOUSE_MDOWN;
+      break;
+    case MouseButton::eSecondary:
+      button = IMEMOUSE_RDOWN;
+      break;
+    default:
+      return NS_OK;
+  }
+
+  // calcurate positioning and offset
+  // char :            JCH1|JCH2|JCH3
+  // offset:           0011 1122 2233
+  // positioning:      2301 2301 2301
+  LayoutDeviceIntPoint cursorPos =
+      aIMENotification.mMouseButtonEventData.mCursorPos;
+  LayoutDeviceIntRect charRect =
+      aIMENotification.mMouseButtonEventData.mCharRect;
+  int32_t cursorXInChar = cursorPos.x - charRect.X();
+  // The event might hit to zero-width character, see bug 694913.
+  // The reason might be:
+  // * There are some zero-width characters are actually.
+  // * font-size is specified zero.
+  // But nobody reproduced this bug actually...
+  // We should assume that user clicked on right most of the zero-width
+  // character in such case.
+  int positioning = 1;
+  if (charRect.Width() > 0) {
+    positioning = cursorXInChar * 4 / charRect.Width();
+    positioning = (positioning + 2) % 4;
+  }
+
+  int offset =
+      aIMENotification.mMouseButtonEventData.mOffset - compositionStart;
+  if (positioning < 2) {
+    offset++;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::OnMouseButtonEvent, x,y=%d,%d, offset=%d, "
+           "positioning=%d",
+           cursorPos.x.value, cursorPos.y.value, offset, positioning));
+
+  // send MS_MSIME_MOUSE message to default IME window.
+  HWND imeWnd = ::ImmGetDefaultIMEWnd(aWindow->GetWindowHandle());
+  IMEContext context(aWindow);
+  if (::SendMessageW(imeWnd, sWM_MSIME_MOUSE,
+                     MAKELONG(MAKEWORD(button, positioning), offset),
+                     (LPARAM)context.get()) == 1) {
+    return NS_SUCCESS_EVENT_CONSUMED;
+  }
+  return NS_OK;
+}
+
+// static
+bool IMMHandler::OnKeyDownEvent(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                                MSGResult& aResult) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("IMMHandler::OnKeyDownEvent, hWnd=%p, wParam=%08zx, lParam=%08" PRIxLPTR,
+       aWindow->GetWindowHandle(), wParam, lParam));
+  aResult.mConsumed = false;
+  switch (wParam) {
+    case VK_TAB:
+    case VK_PRIOR:
+    case VK_NEXT:
+    case VK_END:
+    case VK_HOME:
+    case VK_LEFT:
+    case VK_UP:
+    case VK_RIGHT:
+    case VK_DOWN:
+    case VK_RETURN:
+      // If IME didn't process the key message (the virtual key code wasn't
+      // converted to VK_PROCESSKEY), and the virtual key code event causes
+      // moving caret or editing text with keeping composing state, we should
+      // cancel the composition here because we cannot support moving
+      // composition string with DOM events (IE also cancels the composition
+      // in same cases).  Then, this event will be dispatched.
+      if (IsComposingOnOurEditor()) {
+        // NOTE: We don't need to cancel the composition on another window.
+        CancelComposition(aWindow, false);
+      }
+      return false;
+    default:
+      return false;
+  }
+}
+
+Maybe<ContentSelection> IMMHandler::QueryContentSelection(nsWindow* aWindow) {
+  WidgetQueryContentEvent querySelectedTextEvent(true, eQuerySelectedText,
+                                                 aWindow);
+  LayoutDeviceIntPoint point(0, 0);
+  aWindow->InitEvent(querySelectedTextEvent, &point);
+  DispatchEvent(aWindow, querySelectedTextEvent);
+  if (NS_WARN_IF(querySelectedTextEvent.Failed())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::Selection::Init, FAILED, due to eQuerySelectedText "
+             "failure"));
+    return Nothing();
+  }
+  // If the window is destroyed during querying selected text, we shouldn't
+  // do anymore.
+  if (aWindow->Destroyed()) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Error,
+        ("  IMMHandler::Selection::Init, FAILED, due to the widget destroyed"));
+    return Nothing();
+  }
+
+  ContentSelection contentSelection(querySelectedTextEvent);
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("IMMHandler::Selection::Init, querySelectedTextEvent={ mReply=%s }",
+           ToString(querySelectedTextEvent.mReply).c_str()));
+
+  if (contentSelection.HasRange() &&
+      !contentSelection.OffsetAndDataRef().IsValid()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  IMMHandler::Selection::Init, FAILED, due to invalid range"));
+    return Nothing();
+  }
+  return Some(contentSelection);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/IMMHandler.h b/widget/windows/IMMHandler.h
new file mode 100644
index 0000000000..e012541fae
--- /dev/null
+++ b/widget/windows/IMMHandler.h
@@ -0,0 +1,427 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef IMMHandler_h_
+#define IMMHandler_h_
+
+#include "mozilla/ContentData.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/WritingModes.h"
+
+#include "windef.h"
+#include "winnetwk.h"
+#include "npapi.h"
+
+#include "nsCOMPtr.h"
+#include "nsIWidget.h"
+#include "nsRect.h"
+#include "nsString.h"
+#include "nsTArray.h"
+
+#include <windows.h>
+
+class nsWindow;
+
+namespace mozilla {
+namespace widget {
+
+struct MSGResult;
+
+class IMEContext final {
+ public:
+  IMEContext() : mWnd(nullptr), mIMC(nullptr) {}
+
+  explicit IMEContext(HWND aWnd);
+  explicit IMEContext(nsWindow* aWindowBase);
+
+  ~IMEContext() { Clear(); }
+
+  HIMC get() const { return mIMC; }
+
+  void Init(HWND aWnd);
+  void Init(nsWindow* aWindowBase);
+  void Clear();
+
+  bool IsValid() const { return !!mIMC; }
+
+  void SetOpenState(bool aOpen) const {
+    if (!mIMC) {
+      return;
+    }
+    ::ImmSetOpenStatus(mIMC, aOpen);
+  }
+
+  bool GetOpenState() const {
+    if (!mIMC) {
+      return false;
+    }
+    return (::ImmGetOpenStatus(mIMC) != FALSE);
+  }
+
+  bool AssociateDefaultContext() {
+    // We assume that there is only default IMC, no new IMC has been created.
+    if (mIMC) {
+      return false;
+    }
+    if (!::ImmAssociateContextEx(mWnd, nullptr, IACE_DEFAULT)) {
+      return false;
+    }
+    mIMC = ::ImmGetContext(mWnd);
+    return (mIMC != nullptr);
+  }
+
+  bool Disassociate() {
+    if (!mIMC) {
+      return false;
+    }
+    if (!::ImmAssociateContextEx(mWnd, nullptr, 0)) {
+      return false;
+    }
+    ::ImmReleaseContext(mWnd, mIMC);
+    mIMC = nullptr;
+    return true;
+  }
+
+ protected:
+  IMEContext(const IMEContext& aOther) { MOZ_CRASH("Don't copy IMEContext"); }
+
+  HWND mWnd;
+  HIMC mIMC;
+};
+
+class IMMHandler final {
+ public:
+  static void Initialize();
+  static void Terminate();
+
+  // If Process*() returns true, the caller shouldn't do anything anymore.
+  static bool ProcessMessage(nsWindow* aWindow, UINT msg, WPARAM& wParam,
+                             LPARAM& lParam, MSGResult& aResult);
+  static bool IsComposing() { return IsComposingOnOurEditor(); }
+  static bool IsComposingOn(nsWindow* aWindow) {
+    return IsComposing() && IsComposingWindow(aWindow);
+  }
+
+#ifdef DEBUG
+  /**
+   * IsIMEAvailable() returns TRUE when current keyboard layout has IME.
+   * Otherwise, FALSE.
+   */
+  static bool IsIMEAvailable() { return !!::ImmIsIME(::GetKeyboardLayout(0)); }
+#endif
+
+  // If aForce is TRUE, these methods doesn't check whether we have composition
+  // or not.  If you don't set it to TRUE, these method doesn't commit/cancel
+  // the composition on uexpected window.
+  static void CommitComposition(nsWindow* aWindow, bool aForce = false);
+  static void CancelComposition(nsWindow* aWindow, bool aForce = false);
+  static void OnFocusChange(bool aFocus, nsWindow* aWindow);
+  static void OnUpdateComposition(nsWindow* aWindow);
+  static void OnSelectionChange(nsWindow* aWindow,
+                                const IMENotification& aIMENotification,
+                                bool aIsIMMActive);
+
+  static IMENotificationRequests GetIMENotificationRequests();
+
+  // Returns NS_SUCCESS_EVENT_CONSUMED if the mouse button event is consumed by
+  // IME.  Otherwise, NS_OK.
+  static nsresult OnMouseButtonEvent(nsWindow* aWindow,
+                                     const IMENotification& aIMENotification);
+
+#define DECL_IS_IME_ACTIVE(aReadableName) \
+  static bool Is##aReadableName##Active();
+
+  // Japanese IMEs
+  DECL_IS_IME_ACTIVE(ATOK2006)
+  DECL_IS_IME_ACTIVE(ATOK2007)
+  DECL_IS_IME_ACTIVE(ATOK2008)
+  DECL_IS_IME_ACTIVE(ATOK2009)
+  DECL_IS_IME_ACTIVE(ATOK2010)
+  DECL_IS_IME_ACTIVE(GoogleJapaneseInput)
+  DECL_IS_IME_ACTIVE(Japanist2003)
+
+#undef DECL_IS_IME_ACTIVE
+
+  /**
+   * IsActiveIMEInBlockList() returns true if we know active keyboard layout's
+   * IME has some crash bugs or something which make some damage to us.  When
+   * this returns true, IMC shouldn't be associated with any windows.
+   */
+  static bool IsActiveIMEInBlockList();
+
+ protected:
+  static void EnsureHandlerInstance();
+
+  static bool IsComposingOnOurEditor();
+  static bool IsComposingWindow(nsWindow* aWindow);
+
+  static bool ShouldDrawCompositionStringOurselves();
+  static bool IsVerticalWritingSupported();
+  // aWindow can be nullptr if it's called without receiving WM_INPUTLANGCHANGE.
+  static void InitKeyboardLayout(nsWindow* aWindow, HKL aKeyboardLayout);
+  static UINT GetKeyboardCodePage();
+
+  /**
+   * Checks whether the window is top level window of the composing window.
+   * In this method, the top level window means in all windows, not only in all
+   * OUR windows.  I.e., if the aWindow is embedded, this always returns FALSE.
+   */
+  static bool IsTopLevelWindowOfComposition(nsWindow* aWindow);
+
+  static bool ProcessInputLangChangeMessage(nsWindow* aWindow, WPARAM wParam,
+                                            LPARAM lParam, MSGResult& aResult);
+
+  IMMHandler();
+  ~IMMHandler();
+
+  // On*() methods return true if the caller of message handler shouldn't do
+  // anything anymore.  Otherwise, false.
+  static bool OnKeyDownEvent(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                             MSGResult& aResult);
+
+  bool OnIMEStartComposition(nsWindow* aWindow, MSGResult& aResult);
+  bool OnIMEComposition(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                        MSGResult& aResult);
+  bool OnIMEEndComposition(nsWindow* aWindow, MSGResult& aResult);
+  bool OnIMERequest(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                    MSGResult& aResult);
+  bool OnChar(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+              MSGResult& aResult);
+  void OnInputLangChange(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                         MSGResult& aResult);
+
+  // These message handlers don't use instance members, we should not create
+  // the instance by the messages.  So, they should be static.
+  static bool OnIMEChar(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                        MSGResult& aResult);
+  static bool OnIMESetContext(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                              MSGResult& aResult);
+  static bool OnIMECompositionFull(nsWindow* aWindow, MSGResult& aResult);
+  static bool OnIMENotify(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                          MSGResult& aResult);
+  static bool OnIMESelect(nsWindow* aWindow, WPARAM wParam, LPARAM lParam,
+                          MSGResult& aResult);
+
+  // The result of Handle* method mean "Processed" when it's TRUE.
+  void HandleStartComposition(nsWindow* aWindow, const IMEContext& aContext);
+  bool HandleComposition(nsWindow* aWindow, const IMEContext& aContext,
+                         LPARAM lParam);
+  // If aCommitString is null, this commits composition with the latest
+  // dispatched data.  Otherwise, commits composition with the value.
+  void HandleEndComposition(nsWindow* aWindow,
+                            const nsAString* aCommitString = nullptr);
+  bool HandleReconvert(nsWindow* aWindow, LPARAM lParam, LRESULT* oResult);
+  bool HandleQueryCharPosition(nsWindow* aWindow, LPARAM lParam,
+                               LRESULT* oResult);
+  bool HandleDocumentFeed(nsWindow* aWindow, LPARAM lParam, LRESULT* oResult);
+
+  /**
+   *  When a window's IME context is activating but we have composition on
+   *  another window, we should commit our composition because IME context is
+   *  shared by all our windows (including plug-ins).
+   *  @param aWindow is a new activated window.
+   *  If aWindow is our composing window, this method does nothing.
+   *  Otherwise, this commits the composition on the previous window.
+   *  If this method did commit a composition, this returns TRUE.
+   */
+  bool CommitCompositionOnPreviousWindow(nsWindow* aWindow);
+
+  /**
+   *  ResolveIMECaretPos
+   *  Convert the caret rect of a composition event to another widget's
+   *  coordinate system.
+   *
+   *  @param aReferenceWidget The origin widget of aCursorRect.
+   *                          Typically, this is mReferenceWidget of the
+   *                          composing events. If the aCursorRect is in screen
+   *                          coordinates, set nullptr.
+   *  @param aCursorRect      The cursor rect.
+   *  @param aNewOriginWidget aOutRect will be in this widget's coordinates. If
+   *                          this is nullptr, aOutRect will be in screen
+   *                          coordinates.
+   *  @param aOutRect         The converted cursor rect.
+   */
+  void ResolveIMECaretPos(nsIWidget* aReferenceWidget,
+                          mozilla::LayoutDeviceIntRect& aCursorRect,
+                          nsIWidget* aNewOriginWidget,
+                          mozilla::LayoutDeviceIntRect& aOutRect);
+
+  bool ConvertToANSIString(const nsString& aStr, UINT aCodePage,
+                           nsACString& aANSIStr);
+
+  bool SetIMERelatedWindowsPos(nsWindow* aWindow, const IMEContext& aContext);
+  /**
+   * GetCharacterRectOfSelectedTextAt() returns character rect of the offset
+   * from the selection start or the start of composition string if there is
+   * a composition.
+   *
+   * @param aWindow         The window which has focus.
+   * @param aOffset         Offset from the selection start or the start of
+   *                        composition string when there is a composition.
+   *                        This must be in the selection range or
+   *                        the composition string.
+   * @param aCharRect       The result.
+   * @param aWritingMode    The writing mode of current selection.  When this
+   *                        is nullptr, this assumes that the selection is in
+   *                        horizontal writing mode.
+   * @return                true if this succeeded to retrieve the rect.
+   *                        Otherwise, false.
+   */
+  bool GetCharacterRectOfSelectedTextAt(
+      nsWindow* aWindow, uint32_t aOffset,
+      mozilla::LayoutDeviceIntRect& aCharRect,
+      mozilla::WritingMode* aWritingMode = nullptr);
+  /**
+   * GetCaretRect() returns caret rect at current selection start.
+   *
+   * @param aWindow         The window which has focus.
+   * @param aCaretRect      The result.
+   * @param aWritingMode    The writing mode of current selection.  When this
+   *                        is nullptr, this assumes that the selection is in
+   *                        horizontal writing mode.
+   * @return                true if this succeeded to retrieve the rect.
+   *                        Otherwise, false.
+   */
+  bool GetCaretRect(nsWindow* aWindow, mozilla::LayoutDeviceIntRect& aCaretRect,
+                    mozilla::WritingMode* aWritingMode = nullptr);
+  void GetCompositionString(const IMEContext& aContext, DWORD aIndex,
+                            nsAString& aCompositionString) const;
+
+  /**
+   * AdjustCompositionFont() makes IME vertical writing mode if it's supported.
+   * If aForceUpdate is true, it will update composition font even if writing
+   * mode isn't being changed.
+   */
+  void AdjustCompositionFont(nsWindow* aWindow, const IMEContext& aContext,
+                             const mozilla::WritingMode& aWritingMode,
+                             bool aForceUpdate = false);
+
+  /**
+   * MaybeAdjustCompositionFont() calls AdjustCompositionFont() when the
+   * locale of active IME is CJK.  Note that this creates an instance even
+   * when there is no composition but the locale is CJK.
+   */
+  static void MaybeAdjustCompositionFont(
+      nsWindow* aWindow, const mozilla::WritingMode& aWritingMode,
+      bool aForceUpdate = false);
+
+  /**
+   *  Get the current target clause of composition string.
+   *  If there are one or more characters whose attribute is ATTR_TARGET_*,
+   *  this returns the first character's offset and its length.
+   *  Otherwise, e.g., the all characters are ATTR_INPUT, this returns
+   *  the composition string range because the all is the current target.
+   *
+   *  aLength can be null (default), but aOffset must not be null.
+   *
+   *  The aOffset value is offset in the contents.  So, when you need offset
+   *  in the composition string, you need to subtract mCompositionStart from it.
+   */
+  bool GetTargetClauseRange(uint32_t* aOffset, uint32_t* aLength = nullptr);
+
+  /**
+   * DispatchEvent() dispatches aEvent if aWidget hasn't been destroyed yet.
+   */
+  static void DispatchEvent(nsWindow* aWindow, WidgetGUIEvent& aEvent);
+
+  /**
+   * DispatchCompositionChangeEvent() dispatches eCompositionChange event
+   * with clause information (it'll be retrieved by CreateTextRangeArray()).
+   * I.e., this should be called only during composing.  If a composition is
+   * being committed, only HandleCompositionEnd() should be called.
+   *
+   * @param aWindow     The window which has the composition.
+   * @param aContext    Native IME context which has the composition.
+   */
+  void DispatchCompositionChangeEvent(nsWindow* aWindow,
+                                      const IMEContext& aContext);
+
+  nsresult EnsureClauseArray(int32_t aCount);
+  nsresult EnsureAttributeArray(int32_t aCount);
+
+  /**
+   * When WM_IME_CHAR is received and passed to DefWindowProc, we need to
+   * record the messages.  In other words, we should record the messages
+   * when we receive WM_IME_CHAR on windowless plug-in (if we have focus,
+   * we always eat them).  When focus is moved from a windowless plug-in to
+   * our window during composition, WM_IME_CHAR messages were received when
+   * the plug-in has focus.  However, WM_CHAR messages are received after the
+   * plug-in lost focus.  So, we need to ignore the WM_CHAR messages because
+   * they make unexpected text input events on us.
+   */
+  nsTArray<MSG> mPassedIMEChar;
+
+  bool IsIMECharRecordsEmpty() { return mPassedIMEChar.IsEmpty(); }
+  void ResetIMECharRecords() { mPassedIMEChar.Clear(); }
+  void DequeueIMECharRecords(WPARAM& wParam, LPARAM& lParam) {
+    MSG msg = mPassedIMEChar.ElementAt(0);
+    wParam = msg.wParam;
+    lParam = msg.lParam;
+    mPassedIMEChar.RemoveElementAt(0);
+  }
+  void EnqueueIMECharRecords(WPARAM wParam, LPARAM lParam) {
+    MSG msg;
+    msg.wParam = wParam;
+    msg.lParam = lParam;
+    mPassedIMEChar.AppendElement(msg);
+  }
+
+  TextEventDispatcher* GetTextEventDispatcherFor(nsWindow* aWindow);
+
+  nsWindow* mComposingWindow;
+  RefPtr<TextEventDispatcher> mDispatcher;
+  nsString mCompositionString;
+  nsTArray<uint32_t> mClauseArray;
+  nsTArray<uint8_t> mAttributeArray;
+
+  int32_t mCursorPosition;
+  uint32_t mCompositionStart;
+
+  // mContentSelection stores the latest selection data only when sHasFocus is
+  // true. Don't access mContentSelection directly.  You should use
+  // GetContentSelectionWithQueryIfNothing() for getting proper state.
+  Maybe<ContentSelection> mContentSelection;
+
+  const Maybe<ContentSelection>& GetContentSelectionWithQueryIfNothing(
+      nsWindow* aWindow) {
+    // When IME has focus, mContentSelection is automatically updated by
+    // NOTIFY_IME_OF_SELECTION_CHANGE.
+    if (sHasFocus) {
+      if (mContentSelection.isNothing()) {
+        // But if this is the first access of mContentSelection, we need to
+        // query selection now.
+        mContentSelection = QueryContentSelection(aWindow);
+      }
+      return mContentSelection;
+    }
+    // Otherwise, i.e., While IME doesn't have focus, we cannot observe
+    // selection changes.  So, in such case, we need to query selection
+    // when it's necessary.
+    static Maybe<ContentSelection> sTempContentSelection;
+    sTempContentSelection = QueryContentSelection(aWindow);
+    return sTempContentSelection;
+  }
+
+  /**
+   * Query content selection on aWindow with WidgetQueryContent event.
+   */
+  static Maybe<ContentSelection> QueryContentSelection(nsWindow* aWindow);
+
+  bool mIsComposing;
+
+  static mozilla::WritingMode sWritingModeOfCompositionFont;
+  static nsString sIMEName;
+  static UINT sCodePage;
+  static DWORD sIMEProperty;
+  static DWORD sIMEUIProperty;
+  static bool sAssumeVerticalWritingModeNotSupported;
+  static bool sHasFocus;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // IMMHandler_h_
diff --git a/widget/windows/InProcessWinCompositorWidget.cpp b/widget/windows/InProcessWinCompositorWidget.cpp
new file mode 100644
index 0000000000..de491b734b
--- /dev/null
+++ b/widget/windows/InProcessWinCompositorWidget.cpp
@@ -0,0 +1,368 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "InProcessWinCompositorWidget.h"
+
+#include "mozilla/StaticPrefs_layers.h"
+#include "mozilla/gfx/DeviceManagerDx.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/layers/Compositor.h"
+#include "mozilla/layers/CompositorThread.h"
+#include "mozilla/webrender/RenderThread.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "gfxPlatform.h"
+#include "HeadlessCompositorWidget.h"
+#include "HeadlessWidget.h"
+#include "nsIWidget.h"
+#include "nsWindow.h"
+#include "VsyncDispatcher.h"
+#include "WinCompositorWindowThread.h"
+#include "VRShMem.h"
+
+#include <ddraw.h>
+
+namespace mozilla::widget {
+
+using namespace mozilla::gfx;
+using namespace mozilla;
+
+/* static */
+RefPtr<CompositorWidget> CompositorWidget::CreateLocal(
+    const CompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions, nsIWidget* aWidget) {
+  if (aInitData.type() ==
+      CompositorWidgetInitData::THeadlessCompositorWidgetInitData) {
+    return new HeadlessCompositorWidget(
+        aInitData.get_HeadlessCompositorWidgetInitData(), aOptions,
+        static_cast<HeadlessWidget*>(aWidget));
+  } else {
+    return new InProcessWinCompositorWidget(
+        aInitData.get_WinCompositorWidgetInitData(), aOptions,
+        static_cast<nsWindow*>(aWidget));
+  }
+}
+
+InProcessWinCompositorWidget::InProcessWinCompositorWidget(
+    const WinCompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions, nsWindow* aWindow)
+    : WinCompositorWidget(aInitData, aOptions),
+      mWindow(aWindow),
+      mWnd(reinterpret_cast<HWND>(aInitData.hWnd())),
+      mTransparentSurfaceLock("mTransparentSurfaceLock"),
+      mTransparencyMode(uint32_t(aInitData.transparencyMode())),
+      mMemoryDC(nullptr),
+      mCompositeDC(nullptr),
+      mLockedBackBufferData(nullptr) {
+  MOZ_ASSERT(mWindow);
+  MOZ_ASSERT(mWnd && ::IsWindow(mWnd));
+
+  // mNotDeferEndRemoteDrawing is set on the main thread during init,
+  // but is only accessed after on the compositor thread.
+  mNotDeferEndRemoteDrawing =
+      StaticPrefs::layers_offmainthreadcomposition_frame_rate() == 0 ||
+      gfxPlatform::IsInLayoutAsapMode() || gfxPlatform::ForceSoftwareVsync();
+}
+
+void InProcessWinCompositorWidget::OnDestroyWindow() {
+  gfx::CriticalSectionAutoEnter presentLock(&mPresentLock);
+  MutexAutoLock lock(mTransparentSurfaceLock);
+  mTransparentSurface = nullptr;
+  mMemoryDC = nullptr;
+}
+
+bool InProcessWinCompositorWidget::OnWindowResize(
+    const LayoutDeviceIntSize& aSize) {
+  return true;
+}
+
+void InProcessWinCompositorWidget::OnWindowModeChange(nsSizeMode aSizeMode) {}
+
+bool InProcessWinCompositorWidget::PreRender(WidgetRenderingContext* aContext) {
+  // This can block waiting for WM_SETTEXT to finish
+  // Using PreRender is unnecessarily pessimistic because
+  // we technically only need to block during the present call
+  // not all of compositor rendering
+  mPresentLock.Enter();
+  return true;
+}
+
+void InProcessWinCompositorWidget::PostRender(
+    WidgetRenderingContext* aContext) {
+  mPresentLock.Leave();
+}
+
+LayoutDeviceIntSize InProcessWinCompositorWidget::GetClientSize() {
+  RECT r;
+  if (!::GetClientRect(mWnd, &r)) {
+    return LayoutDeviceIntSize();
+  }
+  return LayoutDeviceIntSize(r.right - r.left, r.bottom - r.top);
+}
+
+already_AddRefed<gfx::DrawTarget>
+InProcessWinCompositorWidget::StartRemoteDrawing() {
+  MutexAutoLock lock(mTransparentSurfaceLock);
+
+  MOZ_ASSERT(!mCompositeDC);
+
+  RefPtr<gfxASurface> surf;
+  if (TransparencyModeIs(TransparencyMode::Transparent)) {
+    surf = EnsureTransparentSurface();
+  }
+
+  // Must call this after EnsureTransparentSurface(), since it could update
+  // the DC.
+  HDC dc = GetWindowSurface();
+  if (!surf) {
+    if (!dc) {
+      return nullptr;
+    }
+    uint32_t flags = TransparencyModeIs(TransparencyMode::Opaque)
+                         ? 0
+                         : gfxWindowsSurface::FLAG_IS_TRANSPARENT;
+    surf = new gfxWindowsSurface(dc, flags);
+  }
+
+  IntSize size = surf->GetSize();
+  if (size.width <= 0 || size.height <= 0) {
+    if (dc) {
+      FreeWindowSurface(dc);
+    }
+    return nullptr;
+  }
+
+  RefPtr<DrawTarget> dt =
+      mozilla::gfx::Factory::CreateDrawTargetForCairoSurface(
+          surf->CairoSurface(), size);
+  if (dt) {
+    mCompositeDC = dc;
+  } else {
+    FreeWindowSurface(dc);
+  }
+
+  return dt.forget();
+}
+
+void InProcessWinCompositorWidget::EndRemoteDrawing() {
+  MOZ_ASSERT(!mLockedBackBufferData);
+
+  if (TransparencyModeIs(TransparencyMode::Transparent)) {
+    MOZ_ASSERT(mTransparentSurface);
+    RedrawTransparentWindow();
+  }
+  if (mCompositeDC) {
+    FreeWindowSurface(mCompositeDC);
+  }
+  mCompositeDC = nullptr;
+}
+
+bool InProcessWinCompositorWidget::NeedsToDeferEndRemoteDrawing() {
+  if (mNotDeferEndRemoteDrawing) {
+    return false;
+  }
+
+  IDirectDraw7* ddraw = DeviceManagerDx::Get()->GetDirectDraw();
+  if (!ddraw) {
+    return false;
+  }
+
+  DWORD scanLine = 0;
+  int height = ::GetSystemMetrics(SM_CYSCREEN);
+  HRESULT ret = ddraw->GetScanLine(&scanLine);
+  if (ret == DDERR_VERTICALBLANKINPROGRESS) {
+    scanLine = 0;
+  } else if (ret != DD_OK) {
+    return false;
+  }
+
+  // Check if there is a risk of tearing with GDI.
+  if (static_cast<int>(scanLine) > height / 2) {
+    // No need to defer.
+    return false;
+  }
+
+  return true;
+}
+
+already_AddRefed<gfx::DrawTarget>
+InProcessWinCompositorWidget::GetBackBufferDrawTarget(
+    gfx::DrawTarget* aScreenTarget, const gfx::IntRect& aRect,
+    bool* aOutIsCleared) {
+  MOZ_ASSERT(!mLockedBackBufferData);
+
+  RefPtr<gfx::DrawTarget> target = CompositorWidget::GetBackBufferDrawTarget(
+      aScreenTarget, aRect, aOutIsCleared);
+  if (!target) {
+    return nullptr;
+  }
+
+  MOZ_ASSERT(target->GetBackendType() == BackendType::CAIRO);
+
+  uint8_t* destData;
+  IntSize destSize;
+  int32_t destStride;
+  SurfaceFormat destFormat;
+  if (!target->LockBits(&destData, &destSize, &destStride, &destFormat)) {
+    // LockBits is not supported. Use original DrawTarget.
+    return target.forget();
+  }
+
+  RefPtr<gfx::DrawTarget> dataTarget = Factory::CreateDrawTargetForData(
+      BackendType::CAIRO, destData, destSize, destStride, destFormat);
+  mLockedBackBufferData = destData;
+
+  return dataTarget.forget();
+}
+
+already_AddRefed<gfx::SourceSurface>
+InProcessWinCompositorWidget::EndBackBufferDrawing() {
+  if (mLockedBackBufferData) {
+    MOZ_ASSERT(mLastBackBuffer);
+    mLastBackBuffer->ReleaseBits(mLockedBackBufferData);
+    mLockedBackBufferData = nullptr;
+  }
+  return CompositorWidget::EndBackBufferDrawing();
+}
+
+bool InProcessWinCompositorWidget::InitCompositor(
+    layers::Compositor* aCompositor) {
+  return true;
+}
+
+void InProcessWinCompositorWidget::EnterPresentLock() { mPresentLock.Enter(); }
+
+void InProcessWinCompositorWidget::LeavePresentLock() { mPresentLock.Leave(); }
+
+RefPtr<gfxASurface> InProcessWinCompositorWidget::EnsureTransparentSurface() {
+  mTransparentSurfaceLock.AssertCurrentThreadOwns();
+  MOZ_ASSERT(TransparencyModeIs(TransparencyMode::Transparent));
+
+  IntSize size = GetClientSize().ToUnknownSize();
+  if (!mTransparentSurface || mTransparentSurface->GetSize() != size) {
+    mTransparentSurface = nullptr;
+    mMemoryDC = nullptr;
+    CreateTransparentSurface(size);
+  }
+
+  RefPtr<gfxASurface> surface = mTransparentSurface;
+  return surface.forget();
+}
+
+void InProcessWinCompositorWidget::CreateTransparentSurface(
+    const gfx::IntSize& aSize) {
+  mTransparentSurfaceLock.AssertCurrentThreadOwns();
+  MOZ_ASSERT(!mTransparentSurface && !mMemoryDC);
+  RefPtr<gfxWindowsSurface> surface =
+      new gfxWindowsSurface(aSize, SurfaceFormat::A8R8G8B8_UINT32);
+  mTransparentSurface = surface;
+  mMemoryDC = surface->GetDC();
+}
+
+void InProcessWinCompositorWidget::UpdateTransparency(TransparencyMode aMode) {
+  gfx::CriticalSectionAutoEnter presentLock(&mPresentLock);
+  MutexAutoLock lock(mTransparentSurfaceLock);
+  if (TransparencyModeIs(aMode)) {
+    return;
+  }
+
+  mTransparencyMode = uint32_t(aMode);
+  mTransparentSurface = nullptr;
+  mMemoryDC = nullptr;
+
+  if (aMode == TransparencyMode::Transparent) {
+    EnsureTransparentSurface();
+  }
+}
+
+void InProcessWinCompositorWidget::NotifyVisibilityUpdated(
+    nsSizeMode aSizeMode, bool aIsFullyOccluded) {
+  mSizeMode = aSizeMode;
+  mIsFullyOccluded = aIsFullyOccluded;
+}
+
+nsSizeMode InProcessWinCompositorWidget::GetWindowSizeMode() const {
+  nsSizeMode sizeMode = mSizeMode;
+  return sizeMode;
+}
+
+bool InProcessWinCompositorWidget::GetWindowIsFullyOccluded() const {
+  bool isFullyOccluded = mIsFullyOccluded;
+  return isFullyOccluded;
+}
+
+void InProcessWinCompositorWidget::ClearTransparentWindow() {
+  gfx::CriticalSectionAutoEnter presentLock(&mPresentLock);
+  MutexAutoLock lock(mTransparentSurfaceLock);
+  if (!mTransparentSurface) {
+    return;
+  }
+
+  EnsureTransparentSurface();
+
+  IntSize size = mTransparentSurface->GetSize();
+  if (!size.IsEmpty()) {
+    RefPtr<DrawTarget> drawTarget =
+        gfxPlatform::CreateDrawTargetForSurface(mTransparentSurface, size);
+    if (!drawTarget) {
+      return;
+    }
+    drawTarget->ClearRect(Rect(0, 0, size.width, size.height));
+    RedrawTransparentWindow();
+  }
+}
+
+bool InProcessWinCompositorWidget::RedrawTransparentWindow() {
+  MOZ_ASSERT(TransparencyModeIs(TransparencyMode::Transparent));
+
+  LayoutDeviceIntSize size = GetClientSize();
+
+  ::GdiFlush();
+
+  BLENDFUNCTION bf = {AC_SRC_OVER, 0, 255, AC_SRC_ALPHA};
+  SIZE winSize = {size.width, size.height};
+  POINT srcPos = {0, 0};
+  HWND hWnd = WinUtils::GetTopLevelHWND(mWnd, true);
+  RECT winRect;
+  ::GetWindowRect(hWnd, &winRect);
+
+  // perform the alpha blend
+  return !!::UpdateLayeredWindow(hWnd, nullptr, (POINT*)&winRect, &winSize,
+                                 mMemoryDC, &srcPos, 0, &bf, ULW_ALPHA);
+}
+
+HDC InProcessWinCompositorWidget::GetWindowSurface() {
+  return TransparencyModeIs(TransparencyMode::Transparent) ? mMemoryDC
+                                                           : ::GetDC(mWnd);
+}
+
+void InProcessWinCompositorWidget::FreeWindowSurface(HDC dc) {
+  if (!TransparencyModeIs(TransparencyMode::Transparent)) {
+    ::ReleaseDC(mWnd, dc);
+  }
+}
+
+bool InProcessWinCompositorWidget::IsHidden() const { return ::IsIconic(mWnd); }
+
+nsIWidget* InProcessWinCompositorWidget::RealWidget() { return mWindow; }
+
+void InProcessWinCompositorWidget::ObserveVsync(VsyncObserver* aObserver) {
+  if (RefPtr<CompositorVsyncDispatcher> cvd =
+          mWindow->GetCompositorVsyncDispatcher()) {
+    cvd->SetCompositorVsyncObserver(aObserver);
+  }
+}
+
+void InProcessWinCompositorWidget::UpdateCompositorWnd(
+    const HWND aCompositorWnd, const HWND aParentWnd) {
+  MOZ_ASSERT(layers::CompositorThreadHolder::IsInCompositorThread());
+  MOZ_ASSERT(aCompositorWnd && aParentWnd);
+  MOZ_ASSERT(aParentWnd == mWnd);
+
+  // Since we're in the parent process anyway, we can just call SetParent
+  // directly.
+  ::SetParent(aCompositorWnd, aParentWnd);
+  mSetParentCompleted = true;
+}
+}  // namespace mozilla::widget
diff --git a/widget/windows/InProcessWinCompositorWidget.h b/widget/windows/InProcessWinCompositorWidget.h
new file mode 100644
index 0000000000..e287204461
--- /dev/null
+++ b/widget/windows/InProcessWinCompositorWidget.h
@@ -0,0 +1,111 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_InProcessWinCompositorWidget_h
+#define widget_windows_InProcessWinCompositorWidget_h
+
+#include "WinCompositorWidget.h"
+
+class nsWindow;
+class gfxASurface;
+
+namespace mozilla::widget {
+
+// This is the Windows-specific implementation of CompositorWidget. For
+// the most part it only requires an HWND, however it maintains extra state
+// for transparent windows, as well as for synchronizing WM_SETTEXT messages
+// with the compositor.
+class InProcessWinCompositorWidget final
+    : public WinCompositorWidget,
+      public PlatformCompositorWidgetDelegate {
+ public:
+  InProcessWinCompositorWidget(const WinCompositorWidgetInitData& aInitData,
+                               const layers::CompositorOptions& aOptions,
+                               nsWindow* aWindow);
+
+  bool PreRender(WidgetRenderingContext*) override;
+  void PostRender(WidgetRenderingContext*) override;
+  already_AddRefed<gfx::DrawTarget> StartRemoteDrawing() override;
+  void EndRemoteDrawing() override;
+  bool NeedsToDeferEndRemoteDrawing() override;
+  LayoutDeviceIntSize GetClientSize() override;
+  already_AddRefed<gfx::DrawTarget> GetBackBufferDrawTarget(
+      gfx::DrawTarget* aScreenTarget, const gfx::IntRect& aRect,
+      bool* aOutIsCleared) override;
+  already_AddRefed<gfx::SourceSurface> EndBackBufferDrawing() override;
+  bool InitCompositor(layers::Compositor* aCompositor) override;
+  CompositorWidgetDelegate* AsDelegate() override { return this; }
+  bool IsHidden() const override;
+
+  // PlatformCompositorWidgetDelegate Overrides
+
+  void EnterPresentLock() override;
+  void LeavePresentLock() override;
+  void OnDestroyWindow() override;
+  bool OnWindowResize(const LayoutDeviceIntSize& aSize) override;
+  void OnWindowModeChange(nsSizeMode aSizeMode) override;
+  void UpdateTransparency(TransparencyMode aMode) override;
+  void NotifyVisibilityUpdated(nsSizeMode aSizeMode,
+                               bool aIsFullyOccluded) override;
+  void ClearTransparentWindow() override;
+
+  bool RedrawTransparentWindow();
+
+  // Ensure that a transparent surface exists, then return it.
+  RefPtr<gfxASurface> EnsureTransparentSurface();
+
+  HDC GetTransparentDC() const { return mMemoryDC; }
+
+  mozilla::Mutex& GetTransparentSurfaceLock() {
+    return mTransparentSurfaceLock;
+  }
+
+  nsSizeMode GetWindowSizeMode() const override;
+  bool GetWindowIsFullyOccluded() const override;
+
+  void ObserveVsync(VsyncObserver* aObserver) override;
+  nsIWidget* RealWidget() override;
+
+  void UpdateCompositorWnd(const HWND aCompositorWnd,
+                           const HWND aParentWnd) override;
+  void SetRootLayerTreeID(const layers::LayersId& aRootLayerTreeId) override {}
+
+ private:
+  HDC GetWindowSurface();
+  void FreeWindowSurface(HDC dc);
+
+  void CreateTransparentSurface(const gfx::IntSize& aSize);
+
+  nsWindow* mWindow;
+
+  HWND mWnd;
+
+  gfx::CriticalSection mPresentLock;
+
+  // Transparency handling.
+  mozilla::Mutex mTransparentSurfaceLock MOZ_UNANNOTATED;
+  mozilla::Atomic<uint32_t, MemoryOrdering::Relaxed> mTransparencyMode;
+
+  bool TransparencyModeIs(TransparencyMode aMode) const {
+    return TransparencyMode(uint32_t(mTransparencyMode)) == aMode;
+  }
+
+  // Visibility handling.
+  mozilla::Atomic<nsSizeMode, MemoryOrdering::Relaxed> mSizeMode;
+  mozilla::Atomic<bool, MemoryOrdering::Relaxed> mIsFullyOccluded;
+
+  RefPtr<gfxASurface> mTransparentSurface;
+  HDC mMemoryDC;
+  HDC mCompositeDC;
+
+  // Locked back buffer of BasicCompositor
+  uint8_t* mLockedBackBufferData;
+
+  bool mNotDeferEndRemoteDrawing;
+};
+
+}  // namespace mozilla::widget
+
+#endif  // widget_windows_InProcessWinCompositorWidget_h
diff --git a/widget/windows/InputDeviceUtils.cpp b/widget/windows/InputDeviceUtils.cpp
new file mode 100644
index 0000000000..3636b93d6a
--- /dev/null
+++ b/widget/windows/InputDeviceUtils.cpp
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "InputDeviceUtils.h"
+
+#define INITGUID
+#include <dbt.h>
+#include <hidclass.h>
+#include <ntddmou.h>
+#include <setupapi.h>
+
+namespace mozilla {
+namespace widget {
+
+HDEVNOTIFY
+InputDeviceUtils::RegisterNotification(HWND aHwnd) {
+  DEV_BROADCAST_DEVICEINTERFACE filter = {};
+
+  filter.dbcc_size = sizeof(DEV_BROADCAST_DEVICEINTERFACE);
+  filter.dbcc_devicetype = DBT_DEVTYP_DEVICEINTERFACE;
+  // Some touchsreen devices are not GUID_DEVINTERFACE_MOUSE, so here we use
+  // GUID_DEVINTERFACE_HID instead.
+  filter.dbcc_classguid = GUID_DEVINTERFACE_HID;
+  return RegisterDeviceNotification(aHwnd, &filter,
+                                    DEVICE_NOTIFY_WINDOW_HANDLE);
+}
+
+void InputDeviceUtils::UnregisterNotification(HDEVNOTIFY aHandle) {
+  if (!aHandle) {
+    return;
+  }
+  UnregisterDeviceNotification(aHandle);
+}
+
+DWORD
+InputDeviceUtils::CountMouseDevices() {
+  HDEVINFO hdev =
+      SetupDiGetClassDevs(&GUID_DEVINTERFACE_MOUSE, nullptr, nullptr,
+                          DIGCF_DEVICEINTERFACE | DIGCF_PRESENT);
+  if (hdev == INVALID_HANDLE_VALUE) {
+    return 0;
+  }
+
+  DWORD count = 0;
+  SP_INTERFACE_DEVICE_DATA info = {};
+  info.cbSize = sizeof(SP_INTERFACE_DEVICE_DATA);
+  while (SetupDiEnumDeviceInterfaces(hdev, nullptr, &GUID_DEVINTERFACE_MOUSE,
+                                     count, &info)) {
+    if (info.Flags & SPINT_ACTIVE) {
+      count++;
+    }
+  }
+  SetupDiDestroyDeviceInfoList(hdev);
+  return count;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/InputDeviceUtils.h b/widget/windows/InputDeviceUtils.h
new file mode 100644
index 0000000000..d16698a03a
--- /dev/null
+++ b/widget/windows/InputDeviceUtils.h
@@ -0,0 +1,26 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_InputDeviceUtils_h__
+#define mozilla_widget_InputDeviceUtils_h__
+
+#include <windows.h>
+
+namespace mozilla {
+namespace widget {
+
+class InputDeviceUtils {
+ public:
+  static HDEVNOTIFY RegisterNotification(HWND aHwnd);
+  static void UnregisterNotification(HDEVNOTIFY aHandle);
+
+  // Returns the number of mouse type devices connected to this system.
+  static DWORD CountMouseDevices();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+#endif  // mozilla_widget_InputDeviceUtils_h__
diff --git a/widget/windows/JumpListBuilder.cpp b/widget/windows/JumpListBuilder.cpp
new file mode 100644
index 0000000000..80b1c29aa7
--- /dev/null
+++ b/widget/windows/JumpListBuilder.cpp
@@ -0,0 +1,818 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <windows.h>
+#include <shobjidl.h>
+#include <propkey.h>
+#include <propvarutil.h>
+#include <shellapi.h>
+#include "JumpListBuilder.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/WindowsJumpListShortcutDescriptionBinding.h"
+#include "mozilla/mscom/EnsureMTA.h"
+#include "nsIFile.h"
+#include "nsIObserverService.h"
+#include "nsServiceManagerUtils.h"
+#include "WinUtils.h"
+
+using mozilla::dom::Promise;
+using mozilla::dom::WindowsJumpListShortcutDescription;
+
+namespace mozilla {
+namespace widget {
+
+NS_IMPL_ISUPPORTS(JumpListBuilder, nsIJumpListBuilder, nsIObserver)
+
+#define TOPIC_PROFILE_BEFORE_CHANGE "profile-before-change"
+#define TOPIC_CLEAR_PRIVATE_DATA "clear-private-data"
+
+// The amount of time, in milliseconds, that our IO thread will stay alive after
+// the last event it processes.
+#define DEFAULT_THREAD_TIMEOUT_MS 30000
+
+const char kPrefTaskbarEnabled[] = "browser.taskbar.lists.enabled";
+
+/**
+ * A wrapper around a ICustomDestinationList that implements the JumpListBackend
+ * interface. This is an implementation of JumpListBackend that actually causes
+ * items to appear in a Windows jump list.
+ */
+class NativeJumpListBackend : public JumpListBackend {
+  // We use NS_INLINE_DECL_REFCOUNTING_ONEVENTTARGET because this
+  // class might be destroyed on a different thread than the one it
+  // was created on, since it's maintained by a LazyIdleThread.
+  //
+  // This is a workaround for bug 1648031.
+  NS_INLINE_DECL_REFCOUNTING_ONEVENTTARGET(JumpListBackend, override)
+
+  NativeJumpListBackend() {
+    MOZ_ASSERT(!NS_IsMainThread());
+
+    mscom::EnsureMTA([&]() {
+      RefPtr<ICustomDestinationList> destList;
+      HRESULT hr = ::CoCreateInstance(
+          CLSID_DestinationList, nullptr, CLSCTX_INPROC_SERVER,
+          IID_ICustomDestinationList, getter_AddRefs(destList));
+      if (FAILED(hr)) {
+        return;
+      }
+
+      mWindowsDestList = destList;
+    });
+  }
+
+  virtual bool IsAvailable() override {
+    MOZ_ASSERT(!NS_IsMainThread());
+    return mWindowsDestList != nullptr;
+  }
+
+  virtual HRESULT SetAppID(LPCWSTR pszAppID) override {
+    MOZ_ASSERT(!NS_IsMainThread());
+    MOZ_ASSERT(mWindowsDestList);
+
+    return mWindowsDestList->SetAppID(pszAppID);
+  }
+
+  virtual HRESULT BeginList(UINT* pcMinSlots, REFIID riid,
+                            void** ppv) override {
+    MOZ_ASSERT(!NS_IsMainThread());
+    MOZ_ASSERT(mWindowsDestList);
+
+    return mWindowsDestList->BeginList(pcMinSlots, riid, ppv);
+  }
+
+  virtual HRESULT AddUserTasks(IObjectArray* poa) override {
+    MOZ_ASSERT(!NS_IsMainThread());
+    MOZ_ASSERT(mWindowsDestList);
+
+    return mWindowsDestList->AddUserTasks(poa);
+  }
+
+  virtual HRESULT AppendCategory(LPCWSTR pszCategory,
+                                 IObjectArray* poa) override {
+    MOZ_ASSERT(!NS_IsMainThread());
+    MOZ_ASSERT(mWindowsDestList);
+
+    return mWindowsDestList->AppendCategory(pszCategory, poa);
+  }
+
+  virtual HRESULT CommitList() override {
+    MOZ_ASSERT(!NS_IsMainThread());
+    MOZ_ASSERT(mWindowsDestList);
+
+    return mWindowsDestList->CommitList();
+  }
+
+  virtual HRESULT AbortList() override {
+    MOZ_ASSERT(!NS_IsMainThread());
+    MOZ_ASSERT(mWindowsDestList);
+
+    return mWindowsDestList->AbortList();
+  }
+
+  virtual HRESULT DeleteList(LPCWSTR pszAppID) override {
+    MOZ_ASSERT(!NS_IsMainThread());
+    MOZ_ASSERT(mWindowsDestList);
+
+    return mWindowsDestList->DeleteList(pszAppID);
+  }
+
+  virtual HRESULT AppendKnownCategory(KNOWNDESTCATEGORY category) override {
+    MOZ_ASSERT(!NS_IsMainThread());
+    MOZ_ASSERT(mWindowsDestList);
+
+    return mWindowsDestList->AppendKnownCategory(category);
+  }
+
+ protected:
+  virtual ~NativeJumpListBackend() override{};
+
+ private:
+  RefPtr<ICustomDestinationList> mWindowsDestList;
+};
+
+JumpListBuilder::JumpListBuilder(const nsAString& aAppUserModelId,
+                                 RefPtr<JumpListBackend> aTestingBackend) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  mAppUserModelId.Assign(aAppUserModelId);
+
+  Preferences::AddStrongObserver(this, kPrefTaskbarEnabled);
+
+  // Make a lazy thread for any IO.
+  mIOThread = new LazyIdleThread(DEFAULT_THREAD_TIMEOUT_MS, "Jump List",
+                                 LazyIdleThread::ManualShutdown);
+
+  nsCOMPtr<nsIObserverService> observerService =
+      do_GetService("@mozilla.org/observer-service;1");
+  if (observerService) {
+    observerService->AddObserver(this, TOPIC_PROFILE_BEFORE_CHANGE, false);
+    observerService->AddObserver(this, TOPIC_CLEAR_PRIVATE_DATA, false);
+  }
+
+  nsCOMPtr<nsIRunnable> runnable;
+
+  if (aTestingBackend) {
+    // Dispatch a task that hands a reference to the testing backend
+    // to the background thread. The testing backend was probably
+    // constructed on the main thread, and is responsible for doing
+    // any locking as well as cleanup.
+    runnable = NewRunnableMethod<RefPtr<JumpListBackend>>(
+        "SetupTestingBackend", this, &JumpListBuilder::DoSetupTestingBackend,
+        aTestingBackend);
+
+  } else {
+    // Dispatch a task that constructs the native jump list backend.
+    runnable = NewRunnableMethod("SetupBackend", this,
+                                 &JumpListBuilder::DoSetupBackend);
+  }
+
+  mIOThread->Dispatch(runnable, NS_DISPATCH_NORMAL);
+
+  // MSIX packages explicitly do not support setting the appid from within
+  // the app, as it is set in the package manifest instead.
+  if (!mozilla::widget::WinUtils::HasPackageIdentity()) {
+    mIOThread->Dispatch(
+        NewRunnableMethod<nsString>(
+            "SetAppID", this, &JumpListBuilder::DoSetAppID, aAppUserModelId),
+        NS_DISPATCH_NORMAL);
+  }
+}
+
+JumpListBuilder::~JumpListBuilder() {
+  Preferences::RemoveObserver(this, kPrefTaskbarEnabled);
+}
+
+void JumpListBuilder::DoSetupTestingBackend(
+    RefPtr<JumpListBackend> aTestingBackend) {
+  MOZ_ASSERT(!NS_IsMainThread());
+  mJumpListBackend = aTestingBackend;
+}
+
+void JumpListBuilder::DoSetupBackend() {
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(!mJumpListBackend);
+  mJumpListBackend = new NativeJumpListBackend();
+}
+
+void JumpListBuilder::DoShutdownBackend() {
+  MOZ_ASSERT(!NS_IsMainThread());
+  mJumpListBackend = nullptr;
+}
+
+void JumpListBuilder::DoSetAppID(nsString aAppUserModelID) {
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(mJumpListBackend);
+  mJumpListBackend->SetAppID(aAppUserModelID.get());
+}
+
+NS_IMETHODIMP
+JumpListBuilder::ObtainAndCacheFavicon(nsIURI* aFaviconURI,
+                                       nsAString& aCachedIconPath) {
+  MOZ_ASSERT(NS_IsMainThread());
+  nsString iconFilePath;
+  nsresult rv = mozilla::widget::FaviconHelper::ObtainCachedIconFile(
+      aFaviconURI, iconFilePath, mIOThread, false);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  aCachedIconPath = iconFilePath;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+JumpListBuilder::IsAvailable(JSContext* aCx, Promise** aPromise) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPromise);
+  MOZ_ASSERT(mIOThread);
+
+  ErrorResult result;
+  RefPtr<Promise> promise =
+      Promise::Create(xpc::CurrentNativeGlobal(aCx), result);
+
+  if (MOZ_UNLIKELY(result.Failed())) {
+    return result.StealNSResult();
+  }
+
+  nsMainThreadPtrHandle<Promise> promiseHolder(
+      new nsMainThreadPtrHolder<Promise>("JumpListBuilder::IsAvailable promise",
+                                         promise));
+
+  nsCOMPtr<nsIRunnable> runnable =
+      NewRunnableMethod<nsMainThreadPtrHandle<Promise>>(
+          "IsAvailable", this, &JumpListBuilder::DoIsAvailable,
+          std::move(promiseHolder));
+  nsresult rv = mIOThread->Dispatch(runnable, NS_DISPATCH_NORMAL);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  promise.forget(aPromise);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+JumpListBuilder::CheckForRemovals(JSContext* aCx, Promise** aPromise) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPromise);
+  MOZ_ASSERT(mIOThread);
+
+  ErrorResult result;
+  RefPtr<Promise> promise =
+      Promise::Create(xpc::CurrentNativeGlobal(aCx), result);
+
+  if (MOZ_UNLIKELY(result.Failed())) {
+    return result.StealNSResult();
+  }
+
+  nsMainThreadPtrHandle<Promise> promiseHolder(
+      new nsMainThreadPtrHolder<Promise>(
+          "JumpListBuilder::CheckForRemovals promise", promise));
+
+  nsCOMPtr<nsIRunnable> runnable =
+      NewRunnableMethod<nsMainThreadPtrHandle<Promise>>(
+          "CheckForRemovals", this, &JumpListBuilder::DoCheckForRemovals,
+          std::move(promiseHolder));
+
+  nsresult rv = mIOThread->Dispatch(runnable, NS_DISPATCH_NORMAL);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  promise.forget(aPromise);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+JumpListBuilder::PopulateJumpList(
+    const nsTArray<JS::Value>& aTaskDescriptions, const nsAString& aCustomTitle,
+    const nsTArray<JS::Value>& aCustomDescriptions, JSContext* aCx,
+    Promise** aPromise) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPromise);
+  MOZ_ASSERT(mIOThread);
+
+  if (aCustomDescriptions.Length() && aCustomTitle.IsEmpty()) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  // Get rid of the old icons
+  nsCOMPtr<nsIRunnable> event =
+      new mozilla::widget::AsyncDeleteAllFaviconsFromDisk(true);
+  mIOThread->Dispatch(event, NS_DISPATCH_NORMAL);
+
+  nsTArray<WindowsJumpListShortcutDescription> taskDescs;
+  for (auto& jsval : aTaskDescriptions) {
+    JS::Rooted<JS::Value> rootedVal(aCx);
+    if (NS_WARN_IF(!dom::ToJSValue(aCx, jsval, &rootedVal))) {
+      return NS_ERROR_INVALID_ARG;
+    }
+
+    WindowsJumpListShortcutDescription desc;
+    if (!desc.Init(aCx, rootedVal)) {
+      return NS_ERROR_INVALID_ARG;
+    }
+
+    taskDescs.AppendElement(std::move(desc));
+  }
+
+  nsTArray<WindowsJumpListShortcutDescription> customDescs;
+  for (auto& jsval : aCustomDescriptions) {
+    JS::Rooted<JS::Value> rootedVal(aCx);
+    if (NS_WARN_IF(!dom::ToJSValue(aCx, jsval, &rootedVal))) {
+      return NS_ERROR_INVALID_ARG;
+    }
+
+    WindowsJumpListShortcutDescription desc;
+    if (!desc.Init(aCx, rootedVal)) {
+      return NS_ERROR_INVALID_ARG;
+    }
+
+    customDescs.AppendElement(std::move(desc));
+  }
+
+  ErrorResult result;
+  RefPtr<Promise> promise =
+      Promise::Create(xpc::CurrentNativeGlobal(aCx), result);
+
+  if (MOZ_UNLIKELY(result.Failed())) {
+    return result.StealNSResult();
+  }
+
+  nsMainThreadPtrHandle<Promise> promiseHolder(
+      new nsMainThreadPtrHolder<Promise>(
+          "JumpListBuilder::PopulateJumpList promise", promise));
+
+  nsCOMPtr<nsIRunnable> runnable = NewRunnableMethod<
+      StoreCopyPassByRRef<nsTArray<WindowsJumpListShortcutDescription>>,
+      nsString,
+      StoreCopyPassByRRef<nsTArray<WindowsJumpListShortcutDescription>>,
+      nsMainThreadPtrHandle<Promise>>(
+      "PopulateJumpList", this, &JumpListBuilder::DoPopulateJumpList,
+      std::move(taskDescs), aCustomTitle, std::move(customDescs),
+      std::move(promiseHolder));
+  nsresult rv = mIOThread->Dispatch(runnable, NS_DISPATCH_NORMAL);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  promise.forget(aPromise);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+JumpListBuilder::ClearJumpList(JSContext* aCx, Promise** aPromise) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aPromise);
+  MOZ_ASSERT(mIOThread);
+
+  ErrorResult result;
+  RefPtr<Promise> promise =
+      Promise::Create(xpc::CurrentNativeGlobal(aCx), result);
+
+  if (MOZ_UNLIKELY(result.Failed())) {
+    return result.StealNSResult();
+  }
+
+  nsMainThreadPtrHandle<Promise> promiseHolder(
+      new nsMainThreadPtrHolder<Promise>(
+          "JumpListBuilder::ClearJumpList promise", promise));
+
+  nsCOMPtr<nsIRunnable> runnable =
+      NewRunnableMethod<nsMainThreadPtrHandle<Promise>>(
+          "ClearJumpList", this, &JumpListBuilder::DoClearJumpList,
+          std::move(promiseHolder));
+  nsresult rv = mIOThread->Dispatch(runnable, NS_DISPATCH_NORMAL);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  promise.forget(aPromise);
+  return NS_OK;
+}
+
+void JumpListBuilder::DoIsAvailable(
+    const nsMainThreadPtrHandle<Promise>& aPromiseHolder) {
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(aPromiseHolder);
+
+  if (!mJumpListBackend) {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "DoIsAvailable", [promiseHolder = std::move(aPromiseHolder)]() {
+          promiseHolder.get()->MaybeResolve(false);
+        }));
+    return;
+  }
+
+  bool isAvailable = mJumpListBackend->IsAvailable();
+
+  NS_DispatchToMainThread(NS_NewRunnableFunction(
+      "DoIsAvailable",
+      [promiseHolder = std::move(aPromiseHolder), isAvailable]() {
+        promiseHolder.get()->MaybeResolve(isAvailable);
+      }));
+}
+
+void JumpListBuilder::DoCheckForRemovals(
+    const nsMainThreadPtrHandle<Promise>& aPromiseHolder) {
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(aPromiseHolder);
+
+  nsresult rv = NS_ERROR_UNEXPECTED;
+
+  auto errorHandler = MakeScopeExit([&aPromiseHolder, &rv]() {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "DoCheckForRemovals",
+        [promiseHolder = std::move(aPromiseHolder), rv]() {
+          promiseHolder.get()->MaybeReject(rv);
+        }));
+  });
+
+  MOZ_ASSERT(mJumpListBackend);
+  if (!mJumpListBackend) {
+    return;
+  }
+
+  // Abort any ongoing list building that might not have been committed,
+  // otherwise BeginList will give us problems.
+  Unused << mJumpListBackend->AbortList();
+
+  nsTArray<nsString> urisToRemove;
+  RefPtr<IObjectArray> objArray;
+  uint32_t maxItems = 0;
+
+  HRESULT hr = mJumpListBackend->BeginList(
+      &maxItems,
+      IID_PPV_ARGS(static_cast<IObjectArray**>(getter_AddRefs(objArray))));
+
+  if (FAILED(hr)) {
+    rv = NS_ERROR_UNEXPECTED;
+    return;
+  }
+
+  RemoveIconCacheAndGetJumplistShortcutURIs(objArray, urisToRemove);
+
+  // We began a list in order to get the removals, which we can now abort.
+  Unused << mJumpListBackend->AbortList();
+
+  errorHandler.release();
+
+  NS_DispatchToMainThread(NS_NewRunnableFunction(
+      "DoCheckForRemovals", [urisToRemove = std::move(urisToRemove),
+                             promiseHolder = std::move(aPromiseHolder)]() {
+        promiseHolder.get()->MaybeResolve(urisToRemove);
+      }));
+}
+
+void JumpListBuilder::DoPopulateJumpList(
+    const nsTArray<WindowsJumpListShortcutDescription>&& aTaskDescriptions,
+    const nsAString& aCustomTitle,
+    const nsTArray<WindowsJumpListShortcutDescription>&& aCustomDescriptions,
+    const nsMainThreadPtrHandle<Promise>& aPromiseHolder) {
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(aPromiseHolder);
+
+  nsresult rv = NS_ERROR_UNEXPECTED;
+
+  auto errorHandler = MakeScopeExit([&aPromiseHolder, &rv]() {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "DoPopulateJumpList",
+        [promiseHolder = std::move(aPromiseHolder), rv]() {
+          promiseHolder.get()->MaybeReject(rv);
+        }));
+  });
+
+  MOZ_ASSERT(mJumpListBackend);
+  if (!mJumpListBackend) {
+    return;
+  }
+
+  // Abort any ongoing list building that might not have been committed,
+  // otherwise BeginList will give us problems.
+  Unused << mJumpListBackend->AbortList();
+
+  nsTArray<nsString> urisToRemove;
+  RefPtr<IObjectArray> objArray;
+  uint32_t maxItems = 0;
+
+  HRESULT hr = mJumpListBackend->BeginList(
+      &maxItems,
+      IID_PPV_ARGS(static_cast<IObjectArray**>(getter_AddRefs(objArray))));
+
+  if (FAILED(hr)) {
+    rv = NS_ERROR_UNEXPECTED;
+    return;
+  }
+
+  if (urisToRemove.Length()) {
+    // It'd be nice if we could return a more descriptive error here so that
+    // the caller knows that they should have called checkForRemovals first.
+    rv = NS_ERROR_UNEXPECTED;
+    return;
+  }
+
+  if (aTaskDescriptions.Length()) {
+    RefPtr<IObjectCollection> taskCollection;
+    hr = CoCreateInstance(CLSID_EnumerableObjectCollection, nullptr,
+                          CLSCTX_INPROC_SERVER, IID_IObjectCollection,
+                          getter_AddRefs(taskCollection));
+    if (FAILED(hr)) {
+      rv = NS_ERROR_UNEXPECTED;
+      return;
+    }
+
+    // Start by building the task list
+    for (auto& desc : aTaskDescriptions) {
+      // These should all be ShellLinks
+      RefPtr<IShellLinkW> link;
+      rv = GetShellLinkFromDescription(desc, link);
+      if (NS_FAILED(rv)) {
+        // Let the errorHandler deal with this.
+        return;
+      }
+      taskCollection->AddObject(link);
+    }
+
+    RefPtr<IObjectArray> pTaskArray;
+    hr = taskCollection->QueryInterface(IID_IObjectArray,
+                                        getter_AddRefs(pTaskArray));
+
+    if (FAILED(hr)) {
+      rv = NS_ERROR_UNEXPECTED;
+      return;
+    }
+
+    hr = mJumpListBackend->AddUserTasks(pTaskArray);
+
+    if (FAILED(hr)) {
+      rv = NS_ERROR_FAILURE;
+      return;
+    }
+  }
+
+  if (aCustomDescriptions.Length()) {
+    // Then build the custom list
+    RefPtr<IObjectCollection> customCollection;
+    hr = CoCreateInstance(CLSID_EnumerableObjectCollection, nullptr,
+                          CLSCTX_INPROC_SERVER, IID_IObjectCollection,
+                          getter_AddRefs(customCollection));
+    if (FAILED(hr)) {
+      rv = NS_ERROR_UNEXPECTED;
+      return;
+    }
+
+    for (auto& desc : aCustomDescriptions) {
+      // These should all be ShellLinks
+      RefPtr<IShellLinkW> link;
+      rv = GetShellLinkFromDescription(desc, link);
+      if (NS_FAILED(rv)) {
+        // Let the errorHandler deal with this.
+        return;
+      }
+      customCollection->AddObject(link);
+    }
+
+    RefPtr<IObjectArray> pCustomArray;
+    hr = customCollection->QueryInterface(IID_IObjectArray,
+                                          getter_AddRefs(pCustomArray));
+    if (FAILED(hr)) {
+      rv = NS_ERROR_UNEXPECTED;
+      return;
+    }
+
+    hr = mJumpListBackend->AppendCategory(
+        reinterpret_cast<const wchar_t*>(aCustomTitle.BeginReading()),
+        pCustomArray);
+
+    if (FAILED(hr)) {
+      rv = NS_ERROR_UNEXPECTED;
+      return;
+    }
+  }
+
+  hr = mJumpListBackend->CommitList();
+  if (FAILED(hr)) {
+    rv = NS_ERROR_FAILURE;
+    return;
+  }
+
+  errorHandler.release();
+
+  NS_DispatchToMainThread(NS_NewRunnableFunction(
+      "DoPopulateJumpList", [promiseHolder = std::move(aPromiseHolder)]() {
+        promiseHolder.get()->MaybeResolveWithUndefined();
+      }));
+}
+
+void JumpListBuilder::DoClearJumpList(
+    const nsMainThreadPtrHandle<Promise>& aPromiseHolder) {
+  MOZ_ASSERT(!NS_IsMainThread());
+  MOZ_ASSERT(aPromiseHolder);
+
+  if (!mJumpListBackend) {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "DoClearJumpList", [promiseHolder = std::move(aPromiseHolder)]() {
+          promiseHolder.get()->MaybeReject(NS_ERROR_UNEXPECTED);
+        }));
+    return;
+  }
+
+  if (SUCCEEDED(mJumpListBackend->DeleteList(mAppUserModelId.get()))) {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "DoClearJumpList", [promiseHolder = std::move(aPromiseHolder)]() {
+          promiseHolder.get()->MaybeResolveWithUndefined();
+        }));
+  } else {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "DoClearJumpList", [promiseHolder = std::move(aPromiseHolder)]() {
+          promiseHolder.get()->MaybeReject(NS_ERROR_FAILURE);
+        }));
+  }
+}
+
+// RemoveIconCacheAndGetJumplistShortcutURIs - does multiple things to
+// avoid unnecessary extra XPCOM incantations. For each object in the input
+// array,  if it's an IShellLinkW, this deletes the cached icon and adds the
+// url param to a list of URLs to be removed from the places database.
+void JumpListBuilder::RemoveIconCacheAndGetJumplistShortcutURIs(
+    IObjectArray* aObjArray, nsTArray<nsString>& aURISpecs) {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  // Early return here just in case some versions of Windows don't populate this
+  if (!aObjArray) {
+    return;
+  }
+
+  uint32_t count = 0;
+  aObjArray->GetCount(&count);
+
+  for (uint32_t idx = 0; idx < count; idx++) {
+    RefPtr<IShellLinkW> pLink;
+
+    if (FAILED(aObjArray->GetAt(idx, IID_IShellLinkW,
+                                static_cast<void**>(getter_AddRefs(pLink))))) {
+      continue;
+    }
+
+    wchar_t buf[MAX_PATH];
+    HRESULT hres = pLink->GetArguments(buf, MAX_PATH);
+    if (SUCCEEDED(hres)) {
+      LPWSTR* arglist;
+      int32_t numArgs;
+
+      arglist = ::CommandLineToArgvW(buf, &numArgs);
+      if (arglist && numArgs > 0) {
+        nsString spec(arglist[0]);
+        aURISpecs.AppendElement(std::move(spec));
+        ::LocalFree(arglist);
+      }
+    }
+
+    int iconIdx = 0;
+    hres = pLink->GetIconLocation(buf, MAX_PATH, &iconIdx);
+    if (SUCCEEDED(hres)) {
+      nsDependentString spec(buf);
+      DeleteIconFromDisk(spec);
+    }
+  }
+}
+
+void JumpListBuilder::DeleteIconFromDisk(const nsAString& aPath) {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  // Check that we aren't deleting some arbitrary file that is not an icon
+  if (StringTail(aPath, 4).LowerCaseEqualsASCII(".ico")) {
+    // Construct the parent path of the passed in path
+    nsCOMPtr<nsIFile> icoFile;
+    nsresult rv = NS_NewLocalFile(aPath, true, getter_AddRefs(icoFile));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
+    }
+
+    icoFile->Remove(false);
+  }
+}
+
+// Converts a WindowsJumpListShortcutDescription into a IShellLinkW
+nsresult JumpListBuilder::GetShellLinkFromDescription(
+    const WindowsJumpListShortcutDescription& aDesc,
+    RefPtr<IShellLinkW>& aShellLink) {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  HRESULT hr;
+  IShellLinkW* psl;
+
+  // Shell links:
+  // http://msdn.microsoft.com/en-us/library/bb776891(VS.85).aspx
+  // http://msdn.microsoft.com/en-us/library/bb774950(VS.85).aspx
+
+  // Create a IShellLink
+  hr = CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER,
+                        IID_IShellLinkW, (LPVOID*)&psl);
+  if (FAILED(hr)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  // Store the title of the app
+  if (!aDesc.mTitle.IsEmpty()) {
+    IPropertyStore* pPropStore = nullptr;
+    hr = psl->QueryInterface(IID_IPropertyStore, (LPVOID*)&pPropStore);
+    if (FAILED(hr)) {
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    PROPVARIANT pv;
+    ::InitPropVariantFromString(aDesc.mTitle.get(), &pv);
+
+    pPropStore->SetValue(PKEY_Title, pv);
+    pPropStore->Commit();
+    pPropStore->Release();
+
+    PropVariantClear(&pv);
+  }
+
+  // Store the rest of the params
+  hr = psl->SetPath(aDesc.mPath.get());
+
+  // According to the documentation at [1], the maximum description length is
+  // INFOTIPSIZE, so we copy the const string from the description into a buffer
+  // of that maximum size. However, testing reveals that INFOTIPSIZE is still
+  // sometimes too large. MAX_PATH seems to work instead.
+  //
+  // We truncate to MAX_PATH - 1, since nsAutoString's don't include the null
+  // character in their capacity calculations, but the string for IShellLinkW
+  // description does. So by truncating to MAX_PATH - 1, the full contents of
+  // the truncated nsAutoString will be copied into the IShellLink description
+  // buffer.
+  //
+  // [1]:
+  // https://learn.microsoft.com/en-us/windows/win32/api/shobjidl_core/nf-shobjidl_core-ishelllinka-setdescription
+  nsAutoString descriptionCopy(aDesc.mDescription.get());
+  if (descriptionCopy.Length() >= MAX_PATH) {
+    descriptionCopy.Truncate(MAX_PATH - 1);
+  }
+
+  hr = psl->SetDescription(descriptionCopy.get());
+
+  if (aDesc.mArguments.WasPassed() && !aDesc.mArguments.Value().IsEmpty()) {
+    hr = psl->SetArguments(aDesc.mArguments.Value().get());
+  } else {
+    hr = psl->SetArguments(L"");
+  }
+
+  // Set up the fallback icon in the event that a valid icon URI has
+  // not been supplied.
+  hr = psl->SetIconLocation(aDesc.mPath.get(), aDesc.mFallbackIconIndex);
+
+  if (aDesc.mIconPath.WasPassed() && !aDesc.mIconPath.Value().IsEmpty()) {
+    // Always use the first icon in the ICO file, as our encoded icon only has 1
+    // resource
+    hr = psl->SetIconLocation(aDesc.mIconPath.Value().get(), 0);
+  }
+
+  aShellLink = dont_AddRef(psl);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+JumpListBuilder::Observe(nsISupports* aSubject, const char* aTopic,
+                         const char16_t* aData) {
+  MOZ_ASSERT(NS_IsMainThread());
+  NS_ENSURE_ARG_POINTER(aTopic);
+  if (strcmp(aTopic, TOPIC_PROFILE_BEFORE_CHANGE) == 0) {
+    nsCOMPtr<nsIObserverService> observerService =
+        do_GetService("@mozilla.org/observer-service;1");
+    if (observerService) {
+      observerService->RemoveObserver(this, TOPIC_PROFILE_BEFORE_CHANGE);
+      observerService->RemoveObserver(this, TOPIC_CLEAR_PRIVATE_DATA);
+    }
+
+    mIOThread->Dispatch(NewRunnableMethod("ShutdownBackend", this,
+                                          &JumpListBuilder::DoShutdownBackend),
+                        NS_DISPATCH_NORMAL);
+
+    mIOThread->Shutdown();
+  } else if (strcmp(aTopic, "nsPref:changed") == 0 &&
+             nsDependentString(aData).EqualsASCII(kPrefTaskbarEnabled)) {
+    bool enabled = Preferences::GetBool(kPrefTaskbarEnabled, true);
+    if (!enabled) {
+      nsCOMPtr<nsIRunnable> event =
+          new mozilla::widget::AsyncDeleteAllFaviconsFromDisk();
+      mIOThread->Dispatch(event, NS_DISPATCH_NORMAL);
+    }
+  } else if (strcmp(aTopic, TOPIC_CLEAR_PRIVATE_DATA) == 0) {
+    // Delete JumpListCache icons from Disk, if any.
+    nsCOMPtr<nsIRunnable> event =
+        new mozilla::widget::AsyncDeleteAllFaviconsFromDisk(false);
+    mIOThread->Dispatch(event, NS_DISPATCH_NORMAL);
+  }
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/JumpListBuilder.h b/widget/windows/JumpListBuilder.h
new file mode 100644
index 0000000000..e228669f11
--- /dev/null
+++ b/widget/windows/JumpListBuilder.h
@@ -0,0 +1,102 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __JumpListBuilder_h__
+#define __JumpListBuilder_h__
+
+#include "nsIJumpListBuilder.h"
+
+#include "nsIObserver.h"
+#include "nsProxyRelease.h"
+#include "mozilla/LazyIdleThread.h"
+
+namespace mozilla {
+
+namespace dom {
+struct WindowsJumpListShortcutDescription;
+}  // namespace dom
+
+namespace widget {
+
+/**
+ * This is an abstract class for a backend to write to the Windows Jump List.
+ *
+ * It has a 1-to-1 method mapping with ICustomDestinationList. The abtract
+ * class allows us to implement a "fake" backend for automated testing.
+ */
+class JumpListBackend {
+  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
+
+  virtual bool IsAvailable() = 0;
+
+  virtual HRESULT SetAppID(LPCWSTR pszAppID) = 0;
+  virtual HRESULT BeginList(UINT* pcMinSlots, REFIID riid, void** ppv) = 0;
+  virtual HRESULT AddUserTasks(IObjectArray* poa) = 0;
+  virtual HRESULT AppendCategory(LPCWSTR pszCategory, IObjectArray* poa) = 0;
+  virtual HRESULT CommitList() = 0;
+  virtual HRESULT AbortList() = 0;
+  virtual HRESULT DeleteList(LPCWSTR pszAppID) = 0;
+  virtual HRESULT AppendKnownCategory(KNOWNDESTCATEGORY category) = 0;
+
+ protected:
+  virtual ~JumpListBackend() {}
+};
+
+/**
+ * JumpListBuilder is a component that can be used to manage the Windows
+ * Jump List off of the main thread.
+ */
+class JumpListBuilder : public nsIJumpListBuilder, public nsIObserver {
+  virtual ~JumpListBuilder();
+
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIJUMPLISTBUILDER
+  NS_DECL_NSIOBSERVER
+
+  explicit JumpListBuilder(const nsAString& aAppUserModelId,
+                           RefPtr<JumpListBackend> aTestingBackend = nullptr);
+
+ private:
+  // These all run on the lazy helper thread.
+  void DoSetupBackend();
+  void DoSetupTestingBackend(RefPtr<JumpListBackend> aTestingBackend);
+  void DoShutdownBackend();
+  void DoSetAppID(nsString aAppUserModelID);
+  void DoIsAvailable(const nsMainThreadPtrHandle<dom::Promise>& aPromiseHolder);
+  void DoCheckForRemovals(
+      const nsMainThreadPtrHandle<dom::Promise>& aPromiseHolder);
+  void DoPopulateJumpList(
+      const nsTArray<dom::WindowsJumpListShortcutDescription>&&
+          aTaskDescriptions,
+      const nsAString& aCustomTitle,
+      const nsTArray<dom::WindowsJumpListShortcutDescription>&&
+          aCustomDescriptions,
+      const nsMainThreadPtrHandle<dom::Promise>& aPromiseHolder);
+  void DoClearJumpList(
+      const nsMainThreadPtrHandle<dom::Promise>& aPromiseHolder);
+  void RemoveIconCacheAndGetJumplistShortcutURIs(IObjectArray* aObjArray,
+                                                 nsTArray<nsString>& aURISpecs);
+  void DeleteIconFromDisk(const nsAString& aPath);
+  nsresult GetShellLinkFromDescription(
+      const dom::WindowsJumpListShortcutDescription& aDesc,
+      RefPtr<IShellLinkW>& aShellLink);
+
+  // This is written to once during construction on the main thread before the
+  // lazy helper thread is created. After that, the lazy helper thread might
+  // read from it.
+  nsString mAppUserModelId;
+
+  // This is only accessed by the lazy helper thread.
+  RefPtr<JumpListBackend> mJumpListBackend;
+
+  // This is only accessed by the main thread.
+  RefPtr<LazyIdleThread> mIOThread;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __JumpListBuilder_h__ */
diff --git a/widget/windows/KeyboardLayout.cpp b/widget/windows/KeyboardLayout.cpp
new file mode 100644
index 0000000000..3b59aa9319
--- /dev/null
+++ b/widget/windows/KeyboardLayout.cpp
@@ -0,0 +1,5442 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Logging.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/StaticPrefs_ui.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/widget/WinRegistry.h"
+
+#include "nsExceptionHandler.h"
+#include "nsGkAtoms.h"
+#include "nsIUserIdleServiceInternal.h"
+#include "nsIWindowsRegKey.h"
+#include "nsPrintfCString.h"
+#include "nsReadableUtils.h"
+#include "nsServiceManagerUtils.h"
+#include "nsTArray.h"
+#include "nsUnicharUtils.h"
+#include "nsWindowDbg.h"
+
+#include "KeyboardLayout.h"
+#include "WidgetUtils.h"
+#include "WinUtils.h"
+
+#include "npapi.h"
+
+#include <windows.h>
+#include <winnls.h>
+#include <winuser.h>
+#include <algorithm>
+
+#ifndef WINABLEAPI
+#  include <winable.h>
+#endif
+
+// For collecting other people's log, tell them `MOZ_LOG=KeyboardHandler:4,sync`
+// rather than `MOZ_LOG=KeyboardHandler:5,sync` since using `5` may create too
+// big file.
+// Therefore you shouldn't use `LogLevel::Verbose` for logging usual behavior.
+mozilla::LazyLogModule gKeyLog("KeyboardHandler");
+
+namespace mozilla {
+namespace widget {
+
+static const char* const kVirtualKeyName[] = {
+    "NULL",
+    "VK_LBUTTON",
+    "VK_RBUTTON",
+    "VK_CANCEL",
+    "VK_MBUTTON",
+    "VK_XBUTTON1",
+    "VK_XBUTTON2",
+    "0x07",
+    "VK_BACK",
+    "VK_TAB",
+    "0x0A",
+    "0x0B",
+    "VK_CLEAR",
+    "VK_RETURN",
+    "0x0E",
+    "0x0F",
+
+    "VK_SHIFT",
+    "VK_CONTROL",
+    "VK_MENU",
+    "VK_PAUSE",
+    "VK_CAPITAL",
+    "VK_KANA, VK_HANGUL",
+    "0x16",
+    "VK_JUNJA",
+    "VK_FINAL",
+    "VK_HANJA, VK_KANJI",
+    "0x1A",
+    "VK_ESCAPE",
+    "VK_CONVERT",
+    "VK_NONCONVERT",
+    "VK_ACCEPT",
+    "VK_MODECHANGE",
+
+    "VK_SPACE",
+    "VK_PRIOR",
+    "VK_NEXT",
+    "VK_END",
+    "VK_HOME",
+    "VK_LEFT",
+    "VK_UP",
+    "VK_RIGHT",
+    "VK_DOWN",
+    "VK_SELECT",
+    "VK_PRINT",
+    "VK_EXECUTE",
+    "VK_SNAPSHOT",
+    "VK_INSERT",
+    "VK_DELETE",
+    "VK_HELP",
+
+    "VK_0",
+    "VK_1",
+    "VK_2",
+    "VK_3",
+    "VK_4",
+    "VK_5",
+    "VK_6",
+    "VK_7",
+    "VK_8",
+    "VK_9",
+    "0x3A",
+    "0x3B",
+    "0x3C",
+    "0x3D",
+    "0x3E",
+    "0x3F",
+
+    "0x40",
+    "VK_A",
+    "VK_B",
+    "VK_C",
+    "VK_D",
+    "VK_E",
+    "VK_F",
+    "VK_G",
+    "VK_H",
+    "VK_I",
+    "VK_J",
+    "VK_K",
+    "VK_L",
+    "VK_M",
+    "VK_N",
+    "VK_O",
+
+    "VK_P",
+    "VK_Q",
+    "VK_R",
+    "VK_S",
+    "VK_T",
+    "VK_U",
+    "VK_V",
+    "VK_W",
+    "VK_X",
+    "VK_Y",
+    "VK_Z",
+    "VK_LWIN",
+    "VK_RWIN",
+    "VK_APPS",
+    "0x5E",
+    "VK_SLEEP",
+
+    "VK_NUMPAD0",
+    "VK_NUMPAD1",
+    "VK_NUMPAD2",
+    "VK_NUMPAD3",
+    "VK_NUMPAD4",
+    "VK_NUMPAD5",
+    "VK_NUMPAD6",
+    "VK_NUMPAD7",
+    "VK_NUMPAD8",
+    "VK_NUMPAD9",
+    "VK_MULTIPLY",
+    "VK_ADD",
+    "VK_SEPARATOR",
+    "VK_SUBTRACT",
+    "VK_DECIMAL",
+    "VK_DIVIDE",
+
+    "VK_F1",
+    "VK_F2",
+    "VK_F3",
+    "VK_F4",
+    "VK_F5",
+    "VK_F6",
+    "VK_F7",
+    "VK_F8",
+    "VK_F9",
+    "VK_F10",
+    "VK_F11",
+    "VK_F12",
+    "VK_F13",
+    "VK_F14",
+    "VK_F15",
+    "VK_F16",
+
+    "VK_F17",
+    "VK_F18",
+    "VK_F19",
+    "VK_F20",
+    "VK_F21",
+    "VK_F22",
+    "VK_F23",
+    "VK_F24",
+    "0x88",
+    "0x89",
+    "0x8A",
+    "0x8B",
+    "0x8C",
+    "0x8D",
+    "0x8E",
+    "0x8F",
+
+    "VK_NUMLOCK",
+    "VK_SCROLL",
+    "VK_OEM_NEC_EQUAL, VK_OEM_FJ_JISHO",
+    "VK_OEM_FJ_MASSHOU",
+    "VK_OEM_FJ_TOUROKU",
+    "VK_OEM_FJ_LOYA",
+    "VK_OEM_FJ_ROYA",
+    "0x97",
+    "0x98",
+    "0x99",
+    "0x9A",
+    "0x9B",
+    "0x9C",
+    "0x9D",
+    "0x9E",
+    "0x9F",
+
+    "VK_LSHIFT",
+    "VK_RSHIFT",
+    "VK_LCONTROL",
+    "VK_RCONTROL",
+    "VK_LMENU",
+    "VK_RMENU",
+    "VK_BROWSER_BACK",
+    "VK_BROWSER_FORWARD",
+    "VK_BROWSER_REFRESH",
+    "VK_BROWSER_STOP",
+    "VK_BROWSER_SEARCH",
+    "VK_BROWSER_FAVORITES",
+    "VK_BROWSER_HOME",
+    "VK_VOLUME_MUTE",
+    "VK_VOLUME_DOWN",
+    "VK_VOLUME_UP",
+
+    "VK_MEDIA_NEXT_TRACK",
+    "VK_MEDIA_PREV_TRACK",
+    "VK_MEDIA_STOP",
+    "VK_MEDIA_PLAY_PAUSE",
+    "VK_LAUNCH_MAIL",
+    "VK_LAUNCH_MEDIA_SELECT",
+    "VK_LAUNCH_APP1",
+    "VK_LAUNCH_APP2",
+    "0xB8",
+    "0xB9",
+    "VK_OEM_1",
+    "VK_OEM_PLUS",
+    "VK_OEM_COMMA",
+    "VK_OEM_MINUS",
+    "VK_OEM_PERIOD",
+    "VK_OEM_2",
+
+    "VK_OEM_3",
+    "VK_ABNT_C1",
+    "VK_ABNT_C2",
+    "0xC3",
+    "0xC4",
+    "0xC5",
+    "0xC6",
+    "0xC7",
+    "0xC8",
+    "0xC9",
+    "0xCA",
+    "0xCB",
+    "0xCC",
+    "0xCD",
+    "0xCE",
+    "0xCF",
+
+    "0xD0",
+    "0xD1",
+    "0xD2",
+    "0xD3",
+    "0xD4",
+    "0xD5",
+    "0xD6",
+    "0xD7",
+    "0xD8",
+    "0xD9",
+    "0xDA",
+    "VK_OEM_4",
+    "VK_OEM_5",
+    "VK_OEM_6",
+    "VK_OEM_7",
+    "VK_OEM_8",
+
+    "0xE0",
+    "VK_OEM_AX",
+    "VK_OEM_102",
+    "VK_ICO_HELP",
+    "VK_ICO_00",
+    "VK_PROCESSKEY",
+    "VK_ICO_CLEAR",
+    "VK_PACKET",
+    "0xE8",
+    "VK_OEM_RESET",
+    "VK_OEM_JUMP",
+    "VK_OEM_PA1",
+    "VK_OEM_PA2",
+    "VK_OEM_PA3",
+    "VK_OEM_WSCTRL",
+    "VK_OEM_CUSEL",
+
+    "VK_OEM_ATTN",
+    "VK_OEM_FINISH",
+    "VK_OEM_COPY",
+    "VK_OEM_AUTO",
+    "VK_OEM_ENLW",
+    "VK_OEM_BACKTAB",
+    "VK_ATTN",
+    "VK_CRSEL",
+    "VK_EXSEL",
+    "VK_EREOF",
+    "VK_PLAY",
+    "VK_ZOOM",
+    "VK_NONAME",
+    "VK_PA1",
+    "VK_OEM_CLEAR",
+    "0xFF"};
+
+static_assert(sizeof(kVirtualKeyName) / sizeof(const char*) == 0x100,
+              "The virtual key name must be defined just 256 keys");
+
+static const char* GetBoolName(bool aBool) { return aBool ? "true" : "false"; }
+
+static const nsCString GetCharacterCodeName(WPARAM aCharCode) {
+  switch (aCharCode) {
+    case 0x0000:
+      return "NULL (0x0000)"_ns;
+    case 0x0008:
+      return "BACKSPACE (0x0008)"_ns;
+    case 0x0009:
+      return "CHARACTER TABULATION (0x0009)"_ns;
+    case 0x000A:
+      return "LINE FEED (0x000A)"_ns;
+    case 0x000B:
+      return "LINE TABULATION (0x000B)"_ns;
+    case 0x000C:
+      return "FORM FEED (0x000C)"_ns;
+    case 0x000D:
+      return "CARRIAGE RETURN (0x000D)"_ns;
+    case 0x0018:
+      return "CANCEL (0x0018)"_ns;
+    case 0x001B:
+      return "ESCAPE (0x001B)"_ns;
+    case 0x0020:
+      return "SPACE (0x0020)"_ns;
+    case 0x007F:
+      return "DELETE (0x007F)"_ns;
+    case 0x00A0:
+      return "NO-BREAK SPACE (0x00A0)"_ns;
+    case 0x00AD:
+      return "SOFT HYPHEN (0x00AD)"_ns;
+    case 0x2000:
+      return "EN QUAD (0x2000)"_ns;
+    case 0x2001:
+      return "EM QUAD (0x2001)"_ns;
+    case 0x2002:
+      return "EN SPACE (0x2002)"_ns;
+    case 0x2003:
+      return "EM SPACE (0x2003)"_ns;
+    case 0x2004:
+      return "THREE-PER-EM SPACE (0x2004)"_ns;
+    case 0x2005:
+      return "FOUR-PER-EM SPACE (0x2005)"_ns;
+    case 0x2006:
+      return "SIX-PER-EM SPACE (0x2006)"_ns;
+    case 0x2007:
+      return "FIGURE SPACE (0x2007)"_ns;
+    case 0x2008:
+      return "PUNCTUATION SPACE (0x2008)"_ns;
+    case 0x2009:
+      return "THIN SPACE (0x2009)"_ns;
+    case 0x200A:
+      return "HAIR SPACE (0x200A)"_ns;
+    case 0x200B:
+      return "ZERO WIDTH SPACE (0x200B)"_ns;
+    case 0x200C:
+      return "ZERO WIDTH NON-JOINER (0x200C)"_ns;
+    case 0x200D:
+      return "ZERO WIDTH JOINER (0x200D)"_ns;
+    case 0x200E:
+      return "LEFT-TO-RIGHT MARK (0x200E)"_ns;
+    case 0x200F:
+      return "RIGHT-TO-LEFT MARK (0x200F)"_ns;
+    case 0x2029:
+      return "PARAGRAPH SEPARATOR (0x2029)"_ns;
+    case 0x202A:
+      return "LEFT-TO-RIGHT EMBEDDING (0x202A)"_ns;
+    case 0x202B:
+      return "RIGHT-TO-LEFT EMBEDDING (0x202B)"_ns;
+    case 0x202D:
+      return "LEFT-TO-RIGHT OVERRIDE (0x202D)"_ns;
+    case 0x202E:
+      return "RIGHT-TO-LEFT OVERRIDE (0x202E)"_ns;
+    case 0x202F:
+      return "NARROW NO-BREAK SPACE (0x202F)"_ns;
+    case 0x205F:
+      return "MEDIUM MATHEMATICAL SPACE (0x205F)"_ns;
+    case 0x2060:
+      return "WORD JOINER (0x2060)"_ns;
+    case 0x2066:
+      return "LEFT-TO-RIGHT ISOLATE (0x2066)"_ns;
+    case 0x2067:
+      return "RIGHT-TO-LEFT ISOLATE (0x2067)"_ns;
+    case 0x3000:
+      return "IDEOGRAPHIC SPACE (0x3000)"_ns;
+    case 0xFEFF:
+      return "ZERO WIDTH NO-BREAK SPACE (0xFEFF)"_ns;
+    default: {
+      if (aCharCode < ' ' || (aCharCode >= 0x80 && aCharCode < 0xA0)) {
+        return nsPrintfCString("control (0x%04zX)", aCharCode);
+      }
+      if (NS_IS_HIGH_SURROGATE(aCharCode)) {
+        return nsPrintfCString("high surrogate (0x%04zX)", aCharCode);
+      }
+      if (NS_IS_LOW_SURROGATE(aCharCode)) {
+        return nsPrintfCString("low surrogate (0x%04zX)", aCharCode);
+      }
+      return IS_IN_BMP(aCharCode)
+                 ? nsPrintfCString(
+                       "'%s' (0x%04zX)",
+                       NS_ConvertUTF16toUTF8(nsAutoString(aCharCode)).get(),
+                       aCharCode)
+                 : nsPrintfCString(
+                       "'%s' (0x%08zX)",
+                       NS_ConvertUTF16toUTF8(nsAutoString(aCharCode)).get(),
+                       aCharCode);
+    }
+  }
+}
+
+static const nsCString GetKeyLocationName(uint32_t aLocation) {
+  switch (aLocation) {
+    case eKeyLocationLeft:
+      return "KEY_LOCATION_LEFT"_ns;
+    case eKeyLocationRight:
+      return "KEY_LOCATION_RIGHT"_ns;
+    case eKeyLocationStandard:
+      return "KEY_LOCATION_STANDARD"_ns;
+    case eKeyLocationNumpad:
+      return "KEY_LOCATION_NUMPAD"_ns;
+    default:
+      return nsPrintfCString("Unknown (0x%04X)", aLocation);
+  }
+}
+
+static const nsCString GetCharacterCodeNames(const char16_t* aChars,
+                                             uint32_t aLength) {
+  if (!aLength) {
+    return ""_ns;
+  }
+  nsCString result;
+  result.AssignLiteral("\"");
+  StringJoinAppend(result, ", "_ns, Span{aChars, aLength},
+                   [](nsACString& dest, const char16_t charValue) {
+                     dest.Append(GetCharacterCodeName(charValue));
+                   });
+  result.AppendLiteral("\"");
+  return result;
+}
+
+static const nsCString GetCharacterCodeNames(
+    const UniCharsAndModifiers& aUniCharsAndModifiers) {
+  if (aUniCharsAndModifiers.IsEmpty()) {
+    return ""_ns;
+  }
+  nsCString result;
+  result.AssignLiteral("\"");
+  StringJoinAppend(result, ", "_ns, Span{aUniCharsAndModifiers.ToString()},
+                   [](nsACString& dest, const char16_t charValue) {
+                     dest.Append(GetCharacterCodeName(charValue));
+                   });
+  result.AppendLiteral("\"");
+  return result;
+}
+
+class MOZ_STACK_CLASS GetShiftStateName final : public nsAutoCString {
+ public:
+  explicit GetShiftStateName(VirtualKey::ShiftState aShiftState) {
+    if (!aShiftState) {
+      AssignLiteral("none");
+      return;
+    }
+    if (aShiftState & VirtualKey::STATE_SHIFT) {
+      AssignLiteral("Shift");
+      aShiftState &= ~VirtualKey::STATE_SHIFT;
+    }
+    if (aShiftState & VirtualKey::STATE_CONTROL) {
+      MaybeAppendSeparator();
+      AssignLiteral("Ctrl");
+      aShiftState &= ~VirtualKey::STATE_CONTROL;
+    }
+    if (aShiftState & VirtualKey::STATE_ALT) {
+      MaybeAppendSeparator();
+      AssignLiteral("Alt");
+      aShiftState &= ~VirtualKey::STATE_ALT;
+    }
+    if (aShiftState & VirtualKey::STATE_CAPSLOCK) {
+      MaybeAppendSeparator();
+      AssignLiteral("CapsLock");
+      aShiftState &= ~VirtualKey::STATE_CAPSLOCK;
+    }
+    MOZ_ASSERT(!aShiftState);
+  }
+
+ private:
+  void MaybeAppendSeparator() {
+    if (!IsEmpty()) {
+      AppendLiteral(" | ");
+    }
+  }
+};
+
+static const nsCString GetMessageName(UINT aMessage) {
+  switch (aMessage) {
+    case WM_NULL:
+      return "WM_NULL"_ns;
+    case WM_KEYDOWN:
+      return "WM_KEYDOWN"_ns;
+    case WM_KEYUP:
+      return "WM_KEYUP"_ns;
+    case WM_SYSKEYDOWN:
+      return "WM_SYSKEYDOWN"_ns;
+    case WM_SYSKEYUP:
+      return "WM_SYSKEYUP"_ns;
+    case WM_CHAR:
+      return "WM_CHAR"_ns;
+    case WM_UNICHAR:
+      return "WM_UNICHAR"_ns;
+    case WM_SYSCHAR:
+      return "WM_SYSCHAR"_ns;
+    case WM_DEADCHAR:
+      return "WM_DEADCHAR"_ns;
+    case WM_SYSDEADCHAR:
+      return "WM_SYSDEADCHAR"_ns;
+    case WM_APPCOMMAND:
+      return "WM_APPCOMMAND"_ns;
+    case WM_QUIT:
+      return "WM_QUIT"_ns;
+    default:
+      return nsPrintfCString("Unknown Message (0x%04X)", aMessage);
+  }
+}
+
+static const nsCString GetVirtualKeyCodeName(WPARAM aVK) {
+  if (aVK >= ArrayLength(kVirtualKeyName)) {
+    return nsPrintfCString("Invalid (0x%08zX)", aVK);
+  }
+  return nsCString(kVirtualKeyName[aVK]);
+}
+
+static const nsCString GetAppCommandName(WPARAM aCommand) {
+  switch (aCommand) {
+    case APPCOMMAND_BASS_BOOST:
+      return "APPCOMMAND_BASS_BOOST"_ns;
+    case APPCOMMAND_BASS_DOWN:
+      return "APPCOMMAND_BASS_DOWN"_ns;
+    case APPCOMMAND_BASS_UP:
+      return "APPCOMMAND_BASS_UP"_ns;
+    case APPCOMMAND_BROWSER_BACKWARD:
+      return "APPCOMMAND_BROWSER_BACKWARD"_ns;
+    case APPCOMMAND_BROWSER_FAVORITES:
+      return "APPCOMMAND_BROWSER_FAVORITES"_ns;
+    case APPCOMMAND_BROWSER_FORWARD:
+      return "APPCOMMAND_BROWSER_FORWARD"_ns;
+    case APPCOMMAND_BROWSER_HOME:
+      return "APPCOMMAND_BROWSER_HOME"_ns;
+    case APPCOMMAND_BROWSER_REFRESH:
+      return "APPCOMMAND_BROWSER_REFRESH"_ns;
+    case APPCOMMAND_BROWSER_SEARCH:
+      return "APPCOMMAND_BROWSER_SEARCH"_ns;
+    case APPCOMMAND_BROWSER_STOP:
+      return "APPCOMMAND_BROWSER_STOP"_ns;
+    case APPCOMMAND_CLOSE:
+      return "APPCOMMAND_CLOSE"_ns;
+    case APPCOMMAND_COPY:
+      return "APPCOMMAND_COPY"_ns;
+    case APPCOMMAND_CORRECTION_LIST:
+      return "APPCOMMAND_CORRECTION_LIST"_ns;
+    case APPCOMMAND_CUT:
+      return "APPCOMMAND_CUT"_ns;
+    case APPCOMMAND_DICTATE_OR_COMMAND_CONTROL_TOGGLE:
+      return "APPCOMMAND_DICTATE_OR_COMMAND_CONTROL_TOGGLE"_ns;
+    case APPCOMMAND_FIND:
+      return "APPCOMMAND_FIND"_ns;
+    case APPCOMMAND_FORWARD_MAIL:
+      return "APPCOMMAND_FORWARD_MAIL"_ns;
+    case APPCOMMAND_HELP:
+      return "APPCOMMAND_HELP"_ns;
+    case APPCOMMAND_LAUNCH_APP1:
+      return "APPCOMMAND_LAUNCH_APP1"_ns;
+    case APPCOMMAND_LAUNCH_APP2:
+      return "APPCOMMAND_LAUNCH_APP2"_ns;
+    case APPCOMMAND_LAUNCH_MAIL:
+      return "APPCOMMAND_LAUNCH_MAIL"_ns;
+    case APPCOMMAND_LAUNCH_MEDIA_SELECT:
+      return "APPCOMMAND_LAUNCH_MEDIA_SELECT"_ns;
+    case APPCOMMAND_MEDIA_CHANNEL_DOWN:
+      return "APPCOMMAND_MEDIA_CHANNEL_DOWN"_ns;
+    case APPCOMMAND_MEDIA_CHANNEL_UP:
+      return "APPCOMMAND_MEDIA_CHANNEL_UP"_ns;
+    case APPCOMMAND_MEDIA_FAST_FORWARD:
+      return "APPCOMMAND_MEDIA_FAST_FORWARD"_ns;
+    case APPCOMMAND_MEDIA_NEXTTRACK:
+      return "APPCOMMAND_MEDIA_NEXTTRACK"_ns;
+    case APPCOMMAND_MEDIA_PAUSE:
+      return "APPCOMMAND_MEDIA_PAUSE"_ns;
+    case APPCOMMAND_MEDIA_PLAY:
+      return "APPCOMMAND_MEDIA_PLAY"_ns;
+    case APPCOMMAND_MEDIA_PLAY_PAUSE:
+      return "APPCOMMAND_MEDIA_PLAY_PAUSE"_ns;
+    case APPCOMMAND_MEDIA_PREVIOUSTRACK:
+      return "APPCOMMAND_MEDIA_PREVIOUSTRACK"_ns;
+    case APPCOMMAND_MEDIA_RECORD:
+      return "APPCOMMAND_MEDIA_RECORD"_ns;
+    case APPCOMMAND_MEDIA_REWIND:
+      return "APPCOMMAND_MEDIA_REWIND"_ns;
+    case APPCOMMAND_MEDIA_STOP:
+      return "APPCOMMAND_MEDIA_STOP"_ns;
+    case APPCOMMAND_MIC_ON_OFF_TOGGLE:
+      return "APPCOMMAND_MIC_ON_OFF_TOGGLE"_ns;
+    case APPCOMMAND_MICROPHONE_VOLUME_DOWN:
+      return "APPCOMMAND_MICROPHONE_VOLUME_DOWN"_ns;
+    case APPCOMMAND_MICROPHONE_VOLUME_MUTE:
+      return "APPCOMMAND_MICROPHONE_VOLUME_MUTE"_ns;
+    case APPCOMMAND_MICROPHONE_VOLUME_UP:
+      return "APPCOMMAND_MICROPHONE_VOLUME_UP"_ns;
+    case APPCOMMAND_NEW:
+      return "APPCOMMAND_NEW"_ns;
+    case APPCOMMAND_OPEN:
+      return "APPCOMMAND_OPEN"_ns;
+    case APPCOMMAND_PASTE:
+      return "APPCOMMAND_PASTE"_ns;
+    case APPCOMMAND_PRINT:
+      return "APPCOMMAND_PRINT"_ns;
+    case APPCOMMAND_REDO:
+      return "APPCOMMAND_REDO"_ns;
+    case APPCOMMAND_REPLY_TO_MAIL:
+      return "APPCOMMAND_REPLY_TO_MAIL"_ns;
+    case APPCOMMAND_SAVE:
+      return "APPCOMMAND_SAVE"_ns;
+    case APPCOMMAND_SEND_MAIL:
+      return "APPCOMMAND_SEND_MAIL"_ns;
+    case APPCOMMAND_SPELL_CHECK:
+      return "APPCOMMAND_SPELL_CHECK"_ns;
+    case APPCOMMAND_TREBLE_DOWN:
+      return "APPCOMMAND_TREBLE_DOWN"_ns;
+    case APPCOMMAND_TREBLE_UP:
+      return "APPCOMMAND_TREBLE_UP"_ns;
+    case APPCOMMAND_UNDO:
+      return "APPCOMMAND_UNDO"_ns;
+    case APPCOMMAND_VOLUME_DOWN:
+      return "APPCOMMAND_VOLUME_DOWN"_ns;
+    case APPCOMMAND_VOLUME_MUTE:
+      return "APPCOMMAND_VOLUME_MUTE"_ns;
+    case APPCOMMAND_VOLUME_UP:
+      return "APPCOMMAND_VOLUME_UP"_ns;
+    default:
+      return nsPrintfCString("Unknown app command (0x%08zX)", aCommand);
+  }
+}
+
+static const nsCString GetAppCommandDeviceName(LPARAM aDevice) {
+  switch (aDevice) {
+    case FAPPCOMMAND_KEY:
+      return "FAPPCOMMAND_KEY"_ns;
+    case FAPPCOMMAND_MOUSE:
+      return "FAPPCOMMAND_MOUSE"_ns;
+    case FAPPCOMMAND_OEM:
+      return "FAPPCOMMAND_OEM"_ns;
+    default:
+      return nsPrintfCString("Unknown app command device (0x%04" PRIXLPTR ")",
+                             aDevice);
+  }
+};
+
+class MOZ_STACK_CLASS GetAppCommandKeysName final : public nsAutoCString {
+ public:
+  explicit GetAppCommandKeysName(WPARAM aKeys) {
+    if (aKeys & MK_CONTROL) {
+      AppendLiteral("MK_CONTROL");
+      aKeys &= ~MK_CONTROL;
+    }
+    if (aKeys & MK_LBUTTON) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_LBUTTON");
+      aKeys &= ~MK_LBUTTON;
+    }
+    if (aKeys & MK_MBUTTON) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_MBUTTON");
+      aKeys &= ~MK_MBUTTON;
+    }
+    if (aKeys & MK_RBUTTON) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_RBUTTON");
+      aKeys &= ~MK_RBUTTON;
+    }
+    if (aKeys & MK_SHIFT) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_SHIFT");
+      aKeys &= ~MK_SHIFT;
+    }
+    if (aKeys & MK_XBUTTON1) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_XBUTTON1");
+      aKeys &= ~MK_XBUTTON1;
+    }
+    if (aKeys & MK_XBUTTON2) {
+      MaybeAppendSeparator();
+      AppendLiteral("MK_XBUTTON2");
+      aKeys &= ~MK_XBUTTON2;
+    }
+    if (aKeys) {
+      MaybeAppendSeparator();
+      AppendPrintf("Unknown Flags (0x%04zX)", aKeys);
+    }
+    if (IsEmpty()) {
+      AssignLiteral("none (0x0000)");
+    }
+  }
+
+ private:
+  void MaybeAppendSeparator() {
+    if (!IsEmpty()) {
+      AppendLiteral(" | ");
+    }
+  }
+};
+
+static const nsCString ToString(const MSG& aMSG) {
+  nsCString result;
+  result.AssignLiteral("{ message=");
+  result.Append(GetMessageName(aMSG.message).get());
+  result.AppendLiteral(", ");
+  switch (aMSG.message) {
+    case WM_KEYDOWN:
+    case WM_KEYUP:
+    case WM_SYSKEYDOWN:
+    case WM_SYSKEYUP:
+      result.AppendPrintf(
+          "virtual keycode=%s, repeat count=%" PRIdLPTR
+          ", "
+          "scancode=0x%02X, extended key=%s, "
+          "context code=%s, previous key state=%s, "
+          "transition state=%s",
+          GetVirtualKeyCodeName(aMSG.wParam).get(), aMSG.lParam & 0xFFFF,
+          WinUtils::GetScanCode(aMSG.lParam),
+          GetBoolName(WinUtils::IsExtendedScanCode(aMSG.lParam)),
+          GetBoolName((aMSG.lParam & (1 << 29)) != 0),
+          GetBoolName((aMSG.lParam & (1 << 30)) != 0),
+          GetBoolName((aMSG.lParam & (1 << 31)) != 0));
+      break;
+    case WM_CHAR:
+    case WM_DEADCHAR:
+    case WM_SYSCHAR:
+    case WM_SYSDEADCHAR:
+      result.AppendPrintf(
+          "character code=%s, repeat count=%" PRIdLPTR
+          ", "
+          "scancode=0x%02X, extended key=%s, "
+          "context code=%s, previous key state=%s, "
+          "transition state=%s",
+          GetCharacterCodeName(aMSG.wParam).get(), aMSG.lParam & 0xFFFF,
+          WinUtils::GetScanCode(aMSG.lParam),
+          GetBoolName(WinUtils::IsExtendedScanCode(aMSG.lParam)),
+          GetBoolName((aMSG.lParam & (1 << 29)) != 0),
+          GetBoolName((aMSG.lParam & (1 << 30)) != 0),
+          GetBoolName((aMSG.lParam & (1 << 31)) != 0));
+      break;
+    case WM_APPCOMMAND:
+      result.AppendPrintf(
+          "window handle=0x%zx, app command=%s, device=%s, dwKeys=%s",
+          aMSG.wParam,
+          GetAppCommandName(GET_APPCOMMAND_LPARAM(aMSG.lParam)).get(),
+          GetAppCommandDeviceName(GET_DEVICE_LPARAM(aMSG.lParam)).get(),
+          GetAppCommandKeysName(GET_KEYSTATE_LPARAM(aMSG.lParam)).get());
+      break;
+    default:
+      result.AppendPrintf("wParam=%zu, lParam=%" PRIdLPTR, aMSG.wParam,
+                          aMSG.lParam);
+      break;
+  }
+  result.AppendPrintf(", hwnd=0x%p", aMSG.hwnd);
+  return result;
+}
+
+static const nsCString ToString(
+    const UniCharsAndModifiers& aUniCharsAndModifiers) {
+  if (aUniCharsAndModifiers.IsEmpty()) {
+    return "{}"_ns;
+  }
+  nsCString result;
+  result.AssignLiteral("{ ");
+  result.Append(GetCharacterCodeName(aUniCharsAndModifiers.CharAt(0)));
+  for (size_t i = 1; i < aUniCharsAndModifiers.Length(); ++i) {
+    if (aUniCharsAndModifiers.ModifiersAt(i - 1) !=
+        aUniCharsAndModifiers.ModifiersAt(i)) {
+      result.AppendLiteral(" [");
+      result.Append(GetModifiersName(aUniCharsAndModifiers.ModifiersAt(0)));
+      result.AppendLiteral("]");
+    }
+    result.AppendLiteral(", ");
+    result.Append(GetCharacterCodeName(aUniCharsAndModifiers.CharAt(i)));
+  }
+  result.AppendLiteral(" [");
+  uint32_t lastIndex = aUniCharsAndModifiers.Length() - 1;
+  result.Append(GetModifiersName(aUniCharsAndModifiers.ModifiersAt(lastIndex)));
+  result.AppendLiteral("] }");
+  return result;
+}
+
+const nsCString ToString(const ModifierKeyState& aModifierKeyState) {
+  nsCString result;
+  result.AssignLiteral("{ ");
+  result.Append(GetModifiersName(aModifierKeyState.GetModifiers()).get());
+  result.AppendLiteral(" }");
+  return result;
+}
+
+// Unique id counter associated with a keydown / keypress events. Used in
+// identifing keypress events for removal from async event dispatch queue
+// in metrofx after preventDefault is called on keydown events.
+static uint32_t sUniqueKeyEventId = 0;
+
+/*****************************************************************************
+ * mozilla::widget::ModifierKeyState
+ *****************************************************************************/
+
+ModifierKeyState::ModifierKeyState() { Update(); }
+
+ModifierKeyState::ModifierKeyState(Modifiers aModifiers)
+    : mModifiers(aModifiers) {
+  MOZ_ASSERT(!(mModifiers & MODIFIER_ALTGRAPH) || (!IsControl() && !IsAlt()),
+             "Neither MODIFIER_CONTROL nor MODIFIER_ALT should be set "
+             "if MODIFIER_ALTGRAPH is set");
+}
+
+void ModifierKeyState::Update() {
+  mModifiers = 0;
+  if (IS_VK_DOWN(VK_SHIFT)) {
+    mModifiers |= MODIFIER_SHIFT;
+  }
+  // If AltGr key (i.e., VK_RMENU on some keyboard layout) is pressed, only
+  // MODIFIER_ALTGRAPH should be set.  Otherwise, i.e., if both Ctrl and Alt
+  // keys are pressed to emulate AltGr key, MODIFIER_CONTROL and MODIFIER_ALT
+  // keys should be set separately.
+  if (IS_VK_DOWN(VK_RMENU) && KeyboardLayout::GetInstance()->HasAltGr()) {
+    mModifiers |= MODIFIER_ALTGRAPH;
+  } else {
+    if (IS_VK_DOWN(VK_CONTROL)) {
+      mModifiers |= MODIFIER_CONTROL;
+    }
+    if (IS_VK_DOWN(VK_MENU)) {
+      mModifiers |= MODIFIER_ALT;
+    }
+  }
+  if (IS_VK_DOWN(VK_LWIN) || IS_VK_DOWN(VK_RWIN)) {
+    mModifiers |= MODIFIER_META;
+  }
+  if (::GetKeyState(VK_CAPITAL) & 1) {
+    mModifiers |= MODIFIER_CAPSLOCK;
+  }
+  if (::GetKeyState(VK_NUMLOCK) & 1) {
+    mModifiers |= MODIFIER_NUMLOCK;
+  }
+  if (::GetKeyState(VK_SCROLL) & 1) {
+    mModifiers |= MODIFIER_SCROLLLOCK;
+  }
+}
+
+void ModifierKeyState::Unset(Modifiers aRemovingModifiers) {
+  mModifiers &= ~aRemovingModifiers;
+}
+
+void ModifierKeyState::Set(Modifiers aAddingModifiers) {
+  mModifiers |= aAddingModifiers;
+  MOZ_ASSERT(!(mModifiers & MODIFIER_ALTGRAPH) || (!IsControl() && !IsAlt()),
+             "Neither MODIFIER_CONTROL nor MODIFIER_ALT should be set "
+             "if MODIFIER_ALTGRAPH is set");
+}
+
+void ModifierKeyState::InitInputEvent(WidgetInputEvent& aInputEvent) const {
+  aInputEvent.mModifiers = mModifiers;
+
+  switch (aInputEvent.mClass) {
+    case eMouseEventClass:
+    case eMouseScrollEventClass:
+    case eWheelEventClass:
+    case eDragEventClass:
+    case eSimpleGestureEventClass:
+      InitMouseEvent(aInputEvent);
+      break;
+    default:
+      break;
+  }
+}
+
+void ModifierKeyState::InitMouseEvent(WidgetInputEvent& aMouseEvent) const {
+  NS_ASSERTION(aMouseEvent.mClass == eMouseEventClass ||
+                   aMouseEvent.mClass == eWheelEventClass ||
+                   aMouseEvent.mClass == eDragEventClass ||
+                   aMouseEvent.mClass == eSimpleGestureEventClass,
+               "called with non-mouse event");
+
+  WidgetMouseEventBase& mouseEvent = *aMouseEvent.AsMouseEventBase();
+  mouseEvent.mButtons = 0;
+  if (::GetKeyState(VK_LBUTTON) < 0) {
+    mouseEvent.mButtons |= MouseButtonsFlag::ePrimaryFlag;
+  }
+  if (::GetKeyState(VK_RBUTTON) < 0) {
+    mouseEvent.mButtons |= MouseButtonsFlag::eSecondaryFlag;
+  }
+  if (::GetKeyState(VK_MBUTTON) < 0) {
+    mouseEvent.mButtons |= MouseButtonsFlag::eMiddleFlag;
+  }
+  if (::GetKeyState(VK_XBUTTON1) < 0) {
+    mouseEvent.mButtons |= MouseButtonsFlag::e4thFlag;
+  }
+  if (::GetKeyState(VK_XBUTTON2) < 0) {
+    mouseEvent.mButtons |= MouseButtonsFlag::e5thFlag;
+  }
+}
+
+bool ModifierKeyState::IsShift() const {
+  return (mModifiers & MODIFIER_SHIFT) != 0;
+}
+
+bool ModifierKeyState::IsControl() const {
+  return (mModifiers & MODIFIER_CONTROL) != 0;
+}
+
+bool ModifierKeyState::IsAlt() const {
+  return (mModifiers & MODIFIER_ALT) != 0;
+}
+
+bool ModifierKeyState::IsWin() const {
+  return (mModifiers & MODIFIER_META) != 0;
+}
+
+bool ModifierKeyState::MaybeMatchShortcutKey() const {
+  // If Windows key is pressed, even if both Ctrl key and Alt key are pressed,
+  // it's possible to match a shortcut key.
+  if (IsWin()) {
+    return true;
+  }
+  // Otherwise, when both Ctrl key and Alt key are pressed, it shouldn't be
+  // a shortcut key for Windows since it means pressing AltGr key on
+  // some keyboard layouts.
+  if (IsControl() ^ IsAlt()) {
+    return true;
+  }
+  // If no modifier key is active except a lockable modifier nor Shift key,
+  // the key shouldn't match any shortcut keys (there are Space and
+  // Shift+Space, though, let's ignore these special case...).
+  return false;
+}
+
+bool ModifierKeyState::IsCapsLocked() const {
+  return (mModifiers & MODIFIER_CAPSLOCK) != 0;
+}
+
+bool ModifierKeyState::IsNumLocked() const {
+  return (mModifiers & MODIFIER_NUMLOCK) != 0;
+}
+
+bool ModifierKeyState::IsScrollLocked() const {
+  return (mModifiers & MODIFIER_SCROLLLOCK) != 0;
+}
+
+/*****************************************************************************
+ * mozilla::widget::UniCharsAndModifiers
+ *****************************************************************************/
+
+void UniCharsAndModifiers::Append(char16_t aUniChar, Modifiers aModifiers) {
+  mChars.Append(aUniChar);
+  mModifiers.AppendElement(aModifiers);
+}
+
+void UniCharsAndModifiers::FillModifiers(Modifiers aModifiers) {
+  for (size_t i = 0; i < Length(); i++) {
+    mModifiers[i] = aModifiers;
+  }
+}
+
+void UniCharsAndModifiers::OverwriteModifiersIfBeginsWith(
+    const UniCharsAndModifiers& aOther) {
+  if (!BeginsWith(aOther)) {
+    return;
+  }
+  for (size_t i = 0; i < aOther.Length(); ++i) {
+    mModifiers[i] = aOther.mModifiers[i];
+  }
+}
+
+bool UniCharsAndModifiers::UniCharsEqual(
+    const UniCharsAndModifiers& aOther) const {
+  return mChars.Equals(aOther.mChars);
+}
+
+bool UniCharsAndModifiers::UniCharsCaseInsensitiveEqual(
+    const UniCharsAndModifiers& aOther) const {
+  return mChars.Equals(aOther.mChars, nsCaseInsensitiveStringComparator);
+}
+
+bool UniCharsAndModifiers::BeginsWith(
+    const UniCharsAndModifiers& aOther) const {
+  return StringBeginsWith(mChars, aOther.mChars);
+}
+
+UniCharsAndModifiers& UniCharsAndModifiers::operator+=(
+    const UniCharsAndModifiers& aOther) {
+  mChars.Append(aOther.mChars);
+  mModifiers.AppendElements(aOther.mModifiers);
+  return *this;
+}
+
+UniCharsAndModifiers UniCharsAndModifiers::operator+(
+    const UniCharsAndModifiers& aOther) const {
+  UniCharsAndModifiers result(*this);
+  result += aOther;
+  return result;
+}
+
+/*****************************************************************************
+ * mozilla::widget::VirtualKey
+ *****************************************************************************/
+
+// static
+VirtualKey::ShiftState VirtualKey::ModifiersToShiftState(Modifiers aModifiers) {
+  ShiftState state = 0;
+  if (aModifiers & MODIFIER_SHIFT) {
+    state |= STATE_SHIFT;
+  }
+  if (aModifiers & MODIFIER_ALTGRAPH) {
+    state |= STATE_ALTGRAPH;
+  } else {
+    if (aModifiers & MODIFIER_CONTROL) {
+      state |= STATE_CONTROL;
+    }
+    if (aModifiers & MODIFIER_ALT) {
+      state |= STATE_ALT;
+    }
+  }
+  if (aModifiers & MODIFIER_CAPSLOCK) {
+    state |= STATE_CAPSLOCK;
+  }
+  return state;
+}
+
+// static
+Modifiers VirtualKey::ShiftStateToModifiers(ShiftState aShiftState) {
+  Modifiers modifiers = 0;
+  if (aShiftState & STATE_SHIFT) {
+    modifiers |= MODIFIER_SHIFT;
+  }
+  if (aShiftState & STATE_ALTGRAPH) {
+    modifiers |= MODIFIER_ALTGRAPH;
+  } else {
+    if (aShiftState & STATE_CONTROL) {
+      modifiers |= MODIFIER_CONTROL;
+    }
+    if (aShiftState & STATE_ALT) {
+      modifiers |= MODIFIER_ALT;
+    }
+  }
+  if (aShiftState & STATE_CAPSLOCK) {
+    modifiers |= MODIFIER_CAPSLOCK;
+  }
+  return modifiers;
+}
+
+const DeadKeyTable* VirtualKey::MatchingDeadKeyTable(
+    const DeadKeyEntry* aDeadKeyArray, uint32_t aEntries) const {
+  if (!mIsDeadKey) {
+    return nullptr;
+  }
+
+  for (ShiftState shiftState = 0; shiftState < 16; shiftState++) {
+    if (!IsDeadKey(shiftState)) {
+      continue;
+    }
+    const DeadKeyTable* dkt = mShiftStates[shiftState].DeadKey.Table;
+    if (dkt && dkt->IsEqual(aDeadKeyArray, aEntries)) {
+      return dkt;
+    }
+  }
+
+  return nullptr;
+}
+
+void VirtualKey::SetNormalChars(ShiftState aShiftState, const char16_t* aChars,
+                                uint32_t aNumOfChars) {
+  MOZ_ASSERT(aShiftState == ToShiftStateIndex(aShiftState));
+
+  SetDeadKey(aShiftState, false);
+
+  for (uint32_t index = 0; index < aNumOfChars; index++) {
+    // Ignore legacy non-printable control characters
+    mShiftStates[aShiftState].Normal.Chars[index] =
+        (aChars[index] >= 0x20) ? aChars[index] : 0;
+  }
+
+  uint32_t len = ArrayLength(mShiftStates[aShiftState].Normal.Chars);
+  for (uint32_t index = aNumOfChars; index < len; index++) {
+    mShiftStates[aShiftState].Normal.Chars[index] = 0;
+  }
+}
+
+void VirtualKey::SetDeadChar(ShiftState aShiftState, char16_t aDeadChar) {
+  MOZ_ASSERT(aShiftState == ToShiftStateIndex(aShiftState));
+
+  SetDeadKey(aShiftState, true);
+
+  mShiftStates[aShiftState].DeadKey.DeadChar = aDeadChar;
+  mShiftStates[aShiftState].DeadKey.Table = nullptr;
+}
+
+UniCharsAndModifiers VirtualKey::GetUniChars(ShiftState aShiftState) const {
+  UniCharsAndModifiers result = GetNativeUniChars(aShiftState);
+
+  const uint8_t kShiftStateIndex = ToShiftStateIndex(aShiftState);
+  if (!(kShiftStateIndex & STATE_CONTROL_ALT)) {
+    // If neither Alt nor Ctrl key is pressed, just return stored data
+    // for the key.
+    return result;
+  }
+
+  if (result.IsEmpty()) {
+    // If Alt and/or Control are pressed and the key produces no
+    // character, return characters which is produced by the key without
+    // Alt and Control, and return given modifiers as is.
+    result = GetNativeUniChars(kShiftStateIndex & ~STATE_CONTROL_ALT);
+    result.FillModifiers(ShiftStateToModifiers(aShiftState));
+    return result;
+  }
+
+  if (IsAltGrIndex(kShiftStateIndex)) {
+    // If AltGr or both Ctrl and Alt are pressed and the key produces
+    // character(s), we need to clear MODIFIER_ALT and MODIFIER_CONTROL
+    // since TextEditor won't handle eKeyPress event whose mModifiers
+    // has MODIFIER_ALT or MODIFIER_CONTROL.  Additionally, we need to
+    // use MODIFIER_ALTGRAPH when a key produces character(s) with
+    // AltGr or both Ctrl and Alt on Windows.  See following spec issue:
+    // <https://github.com/w3c/uievents/issues/147>
+    Modifiers finalModifiers = ShiftStateToModifiers(aShiftState);
+    finalModifiers &= ~(MODIFIER_ALT | MODIFIER_CONTROL);
+    finalModifiers |= MODIFIER_ALTGRAPH;
+    result.FillModifiers(finalModifiers);
+    return result;
+  }
+
+  // Otherwise, i.e., Alt or Ctrl is pressed and it produces character(s),
+  // check if different character(s) is produced by the key without Alt/Ctrl.
+  // If it produces different character, we need to consume the Alt and
+  // Ctrl modifier for TextEditor.  Otherwise, the key does not produces the
+  // character actually.  So, keep setting Alt and Ctrl modifiers.
+  UniCharsAndModifiers unmodifiedReslt =
+      GetNativeUniChars(kShiftStateIndex & ~STATE_CONTROL_ALT);
+  if (!result.UniCharsEqual(unmodifiedReslt)) {
+    Modifiers finalModifiers = ShiftStateToModifiers(aShiftState);
+    finalModifiers &= ~(MODIFIER_ALT | MODIFIER_CONTROL);
+    result.FillModifiers(finalModifiers);
+  }
+  return result;
+}
+
+UniCharsAndModifiers VirtualKey::GetNativeUniChars(
+    ShiftState aShiftState) const {
+  const uint8_t kShiftStateIndex = ToShiftStateIndex(aShiftState);
+  UniCharsAndModifiers result;
+  Modifiers modifiers = ShiftStateToModifiers(aShiftState);
+  if (IsDeadKey(aShiftState)) {
+    result.Append(mShiftStates[kShiftStateIndex].DeadKey.DeadChar, modifiers);
+    return result;
+  }
+
+  uint32_t len = ArrayLength(mShiftStates[kShiftStateIndex].Normal.Chars);
+  for (uint32_t i = 0;
+       i < len && mShiftStates[kShiftStateIndex].Normal.Chars[i]; i++) {
+    result.Append(mShiftStates[kShiftStateIndex].Normal.Chars[i], modifiers);
+  }
+  return result;
+}
+
+// static
+void VirtualKey::FillKbdState(PBYTE aKbdState, const ShiftState aShiftState) {
+  if (aShiftState & STATE_SHIFT) {
+    aKbdState[VK_SHIFT] |= 0x80;
+  } else {
+    aKbdState[VK_SHIFT] &= ~0x80;
+    aKbdState[VK_LSHIFT] &= ~0x80;
+    aKbdState[VK_RSHIFT] &= ~0x80;
+  }
+
+  if (aShiftState & STATE_ALTGRAPH) {
+    aKbdState[VK_CONTROL] |= 0x80;
+    aKbdState[VK_LCONTROL] |= 0x80;
+    aKbdState[VK_RCONTROL] &= ~0x80;
+    aKbdState[VK_MENU] |= 0x80;
+    aKbdState[VK_LMENU] &= ~0x80;
+    aKbdState[VK_RMENU] |= 0x80;
+  } else {
+    if (aShiftState & STATE_CONTROL) {
+      aKbdState[VK_CONTROL] |= 0x80;
+    } else {
+      aKbdState[VK_CONTROL] &= ~0x80;
+      aKbdState[VK_LCONTROL] &= ~0x80;
+      aKbdState[VK_RCONTROL] &= ~0x80;
+    }
+
+    if (aShiftState & STATE_ALT) {
+      aKbdState[VK_MENU] |= 0x80;
+    } else {
+      aKbdState[VK_MENU] &= ~0x80;
+      aKbdState[VK_LMENU] &= ~0x80;
+      aKbdState[VK_RMENU] &= ~0x80;
+    }
+  }
+
+  if (aShiftState & STATE_CAPSLOCK) {
+    aKbdState[VK_CAPITAL] |= 0x01;
+  } else {
+    aKbdState[VK_CAPITAL] &= ~0x01;
+  }
+}
+
+/*****************************************************************************
+ * mozilla::widget::NativeKey
+ *****************************************************************************/
+
+uint8_t NativeKey::sDispatchedKeyOfAppCommand = 0;
+NativeKey* NativeKey::sLatestInstance = nullptr;
+const MSG NativeKey::sEmptyMSG = {};
+MSG NativeKey::sLastKeyOrCharMSG = {};
+MSG NativeKey::sLastKeyMSG = {};
+char16_t NativeKey::sPendingHighSurrogate = 0;
+
+NativeKey::NativeKey(nsWindow* aWidget, const MSG& aMessage,
+                     const ModifierKeyState& aModKeyState,
+                     HKL aOverrideKeyboardLayout,
+                     nsTArray<FakeCharMsg>* aFakeCharMsgs)
+    : mLastInstance(sLatestInstance),
+      mRemovingMsg(sEmptyMSG),
+      mReceivedMsg(sEmptyMSG),
+      mWidget(aWidget),
+      mDispatcher(aWidget->GetTextEventDispatcher()),
+      mMsg(aMessage),
+      mFocusedWndBeforeDispatch(::GetFocus()),
+      mDOMKeyCode(0),
+      mKeyNameIndex(KEY_NAME_INDEX_Unidentified),
+      mCodeNameIndex(CODE_NAME_INDEX_UNKNOWN),
+      mModKeyState(aModKeyState),
+      mVirtualKeyCode(0),
+      mOriginalVirtualKeyCode(0),
+      mShiftedLatinChar(0),
+      mUnshiftedLatinChar(0),
+      mScanCode(0),
+      mIsExtended(false),
+      mIsRepeat(false),
+      mIsDeadKey(false),
+      mIsPrintableKey(false),
+      mIsSkippableInRemoteProcess(false),
+      mCharMessageHasGone(false),
+      mCanIgnoreModifierStateAtKeyPress(true),
+      mFakeCharMsgs(aFakeCharMsgs && aFakeCharMsgs->Length() ? aFakeCharMsgs
+                                                             : nullptr) {
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p NativeKey::NativeKey(aWidget=0x%p { GetWindowHandle()=0x%p }, "
+           "aMessage=%s, aModKeyState=%s), sLatestInstance=0x%p",
+           this, aWidget, aWidget->GetWindowHandle(), ToString(aMessage).get(),
+           ToString(aModKeyState).get(), sLatestInstance));
+
+  MOZ_ASSERT(aWidget);
+  MOZ_ASSERT(mDispatcher);
+  sLatestInstance = this;
+  KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
+  mKeyboardLayout = KeyboardLayout::GetLayout();
+  if (aOverrideKeyboardLayout && mKeyboardLayout != aOverrideKeyboardLayout) {
+    keyboardLayout->OverrideLayout(aOverrideKeyboardLayout);
+    mKeyboardLayout = keyboardLayout->GetLoadedLayout();
+    MOZ_ASSERT(mKeyboardLayout == aOverrideKeyboardLayout);
+    mIsOverridingKeyboardLayout = true;
+  } else {
+    mIsOverridingKeyboardLayout = false;
+    sLastKeyOrCharMSG = aMessage;
+  }
+
+  if (mMsg.message == WM_APPCOMMAND) {
+    InitWithAppCommand();
+  } else {
+    InitWithKeyOrChar();
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::NativeKey(), mKeyboardLayout=0x%p, "
+           "mFocusedWndBeforeDispatch=0x%p, mDOMKeyCode=%s, "
+           "mKeyNameIndex=%s, mCodeNameIndex=%s, mModKeyState=%s, "
+           "mVirtualKeyCode=%s, mOriginalVirtualKeyCode=%s, "
+           "mCommittedCharsAndModifiers=%s, mInputtingStringAndModifiers=%s, "
+           "mShiftedString=%s, mUnshiftedString=%s, mShiftedLatinChar=%s, "
+           "mUnshiftedLatinChar=%s, mScanCode=0x%04X, mIsExtended=%s, "
+           "mIsRepeat=%s, mIsDeadKey=%s, mIsPrintableKey=%s, "
+           "mIsSkippableInRemoteProcess=%s, mCharMessageHasGone=%s, "
+           "mIsOverridingKeyboardLayout=%s",
+           this, mKeyboardLayout, mFocusedWndBeforeDispatch,
+           GetDOMKeyCodeName(mDOMKeyCode).get(), ToString(mKeyNameIndex).get(),
+           ToString(mCodeNameIndex).get(), ToString(mModKeyState).get(),
+           GetVirtualKeyCodeName(mVirtualKeyCode).get(),
+           GetVirtualKeyCodeName(mOriginalVirtualKeyCode).get(),
+           ToString(mCommittedCharsAndModifiers).get(),
+           ToString(mInputtingStringAndModifiers).get(),
+           ToString(mShiftedString).get(), ToString(mUnshiftedString).get(),
+           GetCharacterCodeName(mShiftedLatinChar).get(),
+           GetCharacterCodeName(mUnshiftedLatinChar).get(), mScanCode,
+           GetBoolName(mIsExtended), GetBoolName(mIsRepeat),
+           GetBoolName(mIsDeadKey), GetBoolName(mIsPrintableKey),
+           GetBoolName(mIsSkippableInRemoteProcess),
+           GetBoolName(mCharMessageHasGone),
+           GetBoolName(mIsOverridingKeyboardLayout)));
+}
+
+void NativeKey::InitIsSkippableForKeyOrChar(const MSG& aLastKeyMSG) {
+  mIsSkippableInRemoteProcess = false;
+
+  if (!mIsRepeat) {
+    // If the message is not repeated key message, the event should be always
+    // handled in remote process even if it's too old.
+    return;
+  }
+
+  // Keyboard utilities may send us some generated messages and such messages
+  // may be marked as "repeated", e.g., SendInput() calls with
+  // KEYEVENTF_UNICODE but without KEYEVENTF_KEYUP.   However, key sequence
+  // comes from such utilities may be really important.  For example, utilities
+  // may send WM_KEYDOWN for VK_BACK to remove previous character and send
+  // WM_KEYDOWN for VK_PACKET to insert a composite character.  Therefore, we
+  // should check if current message and previous key message are caused by
+  // same physical key.  If not, the message may be generated by such
+  // utility.
+  // XXX With this approach, if VK_BACK messages are generated with known
+  //     scancode, we cannot distinguish whether coming VK_BACK message is
+  //     actually repeated by the auto-repeat feature.  Currently, we need
+  //     this hack only for "SinhalaTamil IME" and fortunately, it generates
+  //     VK_BACK messages with odd scancode.  So, we don't need to handle
+  //     VK_BACK specially at least for now.
+
+  if (mCodeNameIndex == CODE_NAME_INDEX_UNKNOWN) {
+    // If current event is not caused by physical key operation, it may be
+    // caused by a keyboard utility.  If so, the event shouldn't be ignored by
+    // BrowserChild since it want to insert the character, delete a character or
+    // move caret.
+    return;
+  }
+
+  if (mOriginalVirtualKeyCode == VK_PACKET) {
+    // If the message is VK_PACKET, that means that a keyboard utility
+    // tries to insert a character.
+    return;
+  }
+
+  switch (mMsg.message) {
+    case WM_KEYDOWN:
+    case WM_SYSKEYDOWN:
+    case WM_CHAR:
+    case WM_SYSCHAR:
+    case WM_DEADCHAR:
+    case WM_SYSDEADCHAR:
+      // However, some keyboard layouts may send some keyboard messages with
+      // activating the bit.  If we dispatch repeated keyboard events, they
+      // may be ignored by BrowserChild due to performance reason.  So, we need
+      // to check if actually a physical key is repeated by the auto-repeat
+      // feature.
+      switch (aLastKeyMSG.message) {
+        case WM_KEYDOWN:
+        case WM_SYSKEYDOWN:
+          if (aLastKeyMSG.wParam == VK_PACKET) {
+            // If the last message was VK_PACKET, that means that a keyboard
+            // utility tried to insert a character.  So, current message is
+            // not repeated key event of the previous event.
+            return;
+          }
+          // Let's check whether current message and previous message are
+          // caused by same physical key.
+          mIsSkippableInRemoteProcess =
+              mScanCode == WinUtils::GetScanCode(aLastKeyMSG.lParam) &&
+              mIsExtended == WinUtils::IsExtendedScanCode(aLastKeyMSG.lParam);
+          return;
+        default:
+          // If previous message is not a keydown, this must not be generated
+          // by the auto-repeat feature.
+          return;
+      }
+    case WM_APPCOMMAND:
+      MOZ_ASSERT_UNREACHABLE(
+          "WM_APPCOMMAND should be handled in "
+          "InitWithAppCommand()");
+      return;
+    default:
+      // keyup message shouldn't be repeated by the auto-repeat feature.
+      return;
+  }
+}
+
+void NativeKey::InitWithKeyOrChar() {
+  MSG lastKeyMSG = sLastKeyMSG;
+  char16_t pendingHighSurrogate = sPendingHighSurrogate;
+  mScanCode = WinUtils::GetScanCode(mMsg.lParam);
+  mIsExtended = WinUtils::IsExtendedScanCode(mMsg.lParam);
+  switch (mMsg.message) {
+    case WM_KEYDOWN:
+    case WM_SYSKEYDOWN:
+      sPendingHighSurrogate = 0;
+      [[fallthrough]];
+    case WM_KEYUP:
+    case WM_SYSKEYUP: {
+      // Modify sLastKeyMSG now since retrieving following char messages may
+      // cause sending another key message if odd tool hooks GetMessage(),
+      // PeekMessage().
+      sLastKeyMSG = mMsg;
+
+      // Note that we don't need to compute raw virtual keycode here even when
+      // it's VK_PROCESS (i.e., already handled by IME) because we need to
+      // export it as DOM_VK_PROCESS and KEY_NAME_INDEX_Process.
+      mOriginalVirtualKeyCode = static_cast<uint8_t>(mMsg.wParam);
+
+      // If the key message is sent from other application like a11y tools, the
+      // scancode value might not be set proper value.  Then, probably the value
+      // is 0.
+      // NOTE: If the virtual keycode can be caused by both non-extended key
+      //       and extended key, the API returns the non-extended key's
+      //       scancode.  E.g., VK_LEFT causes "4" key on numpad.
+      if (!mScanCode && mOriginalVirtualKeyCode != VK_PACKET) {
+        uint16_t scanCodeEx = ComputeScanCodeExFromVirtualKeyCode(mMsg.wParam);
+        if (scanCodeEx) {
+          mScanCode = static_cast<uint8_t>(scanCodeEx & 0xFF);
+          uint8_t extended = static_cast<uint8_t>((scanCodeEx & 0xFF00) >> 8);
+          mIsExtended = (extended == 0xE0) || (extended == 0xE1);
+        }
+      }
+
+      // Most keys are not distinguished as left or right keys.
+      bool isLeftRightDistinguishedKey = false;
+
+      // mOriginalVirtualKeyCode must not distinguish left or right of
+      // Shift, Control or Alt.
+      switch (mOriginalVirtualKeyCode) {
+        case VK_SHIFT:
+        case VK_CONTROL:
+        case VK_MENU:
+          isLeftRightDistinguishedKey = true;
+          break;
+        case VK_LSHIFT:
+        case VK_RSHIFT:
+          mVirtualKeyCode = mOriginalVirtualKeyCode;
+          mOriginalVirtualKeyCode = VK_SHIFT;
+          isLeftRightDistinguishedKey = true;
+          break;
+        case VK_LCONTROL:
+        case VK_RCONTROL:
+          mVirtualKeyCode = mOriginalVirtualKeyCode;
+          mOriginalVirtualKeyCode = VK_CONTROL;
+          isLeftRightDistinguishedKey = true;
+          break;
+        case VK_LMENU:
+        case VK_RMENU:
+          mVirtualKeyCode = mOriginalVirtualKeyCode;
+          mOriginalVirtualKeyCode = VK_MENU;
+          isLeftRightDistinguishedKey = true;
+          break;
+      }
+
+      // If virtual keycode (left-right distinguished keycode) is already
+      // computed, we don't need to do anymore.
+      if (mVirtualKeyCode) {
+        break;
+      }
+
+      // If the keycode doesn't have LR distinguished keycode, we just set
+      // mOriginalVirtualKeyCode to mVirtualKeyCode.  Note that don't compute
+      // it from MapVirtualKeyEx() because the scan code might be wrong if
+      // the message is sent/posted by other application.  Then, we will compute
+      // unexpected keycode from the scan code.
+      if (!isLeftRightDistinguishedKey) {
+        break;
+      }
+
+      NS_ASSERTION(!mVirtualKeyCode,
+                   "mVirtualKeyCode has been computed already");
+
+      // Otherwise, compute the virtual keycode with MapVirtualKeyEx().
+      mVirtualKeyCode = ComputeVirtualKeyCodeFromScanCodeEx();
+
+      // Following code shouldn't be used now because we compute scancode value
+      // if we detect that the sender doesn't set proper scancode.
+      // However, the detection might fail. Therefore, let's keep using this.
+      switch (mOriginalVirtualKeyCode) {
+        case VK_CONTROL:
+          if (mVirtualKeyCode != VK_LCONTROL &&
+              mVirtualKeyCode != VK_RCONTROL) {
+            mVirtualKeyCode = mIsExtended ? VK_RCONTROL : VK_LCONTROL;
+          }
+          break;
+        case VK_MENU:
+          if (mVirtualKeyCode != VK_LMENU && mVirtualKeyCode != VK_RMENU) {
+            mVirtualKeyCode = mIsExtended ? VK_RMENU : VK_LMENU;
+          }
+          break;
+        case VK_SHIFT:
+          if (mVirtualKeyCode != VK_LSHIFT && mVirtualKeyCode != VK_RSHIFT) {
+            // Neither left shift nor right shift is an extended key,
+            // let's use VK_LSHIFT for unknown mapping.
+            mVirtualKeyCode = VK_LSHIFT;
+          }
+          break;
+        default:
+          MOZ_CRASH("Unsupported mOriginalVirtualKeyCode");
+      }
+      break;
+    }
+    case WM_CHAR:
+    case WM_UNICHAR:
+    case WM_SYSCHAR:
+      sPendingHighSurrogate = 0;
+      // If there is another instance and it is trying to remove a char message
+      // from the queue, this message should be handled in the old instance.
+      if (IsAnotherInstanceRemovingCharMessage()) {
+        // XXX Do we need to make mReceivedMsg an array?
+        MOZ_ASSERT(IsEmptyMSG(mLastInstance->mReceivedMsg));
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::InitWithKeyOrChar(), WARNING, detecting another "
+             "instance is trying to remove a char message, so, this instance "
+             "should do nothing, mLastInstance=0x%p, mRemovingMsg=%s, "
+             "mReceivedMsg=%s",
+             this, mLastInstance, ToString(mLastInstance->mRemovingMsg).get(),
+             ToString(mLastInstance->mReceivedMsg).get()));
+        mLastInstance->mReceivedMsg = mMsg;
+        return;
+      }
+
+      // NOTE: If other applications like a11y tools sends WM_*CHAR without
+      //       scancode, we cannot compute virtual keycode.  I.e., with such
+      //       applications, we cannot generate proper KeyboardEvent.code value.
+
+      mVirtualKeyCode = mOriginalVirtualKeyCode =
+          ComputeVirtualKeyCodeFromScanCodeEx();
+      NS_ASSERTION(mVirtualKeyCode, "Failed to compute virtual keycode");
+      break;
+    default: {
+      MOZ_CRASH_UNSAFE_PRINTF("Unsupported message: 0x%04X", mMsg.message);
+      break;
+    }
+  }
+
+  if (!mVirtualKeyCode) {
+    mVirtualKeyCode = mOriginalVirtualKeyCode;
+  }
+
+  KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
+  mDOMKeyCode =
+      keyboardLayout->ConvertNativeKeyCodeToDOMKeyCode(mVirtualKeyCode);
+  // Be aware, keyboard utilities can change non-printable keys to printable
+  // keys.  In such case, we should make the key value as a printable key.
+  // FYI: IsFollowedByPrintableCharMessage() returns true only when it's
+  //      handling a keydown message.
+  mKeyNameIndex =
+      IsFollowedByPrintableCharMessage()
+          ? KEY_NAME_INDEX_USE_STRING
+          : keyboardLayout->ConvertNativeKeyCodeToKeyNameIndex(mVirtualKeyCode);
+  mCodeNameIndex = KeyboardLayout::ConvertScanCodeToCodeNameIndex(
+      GetScanCodeWithExtendedFlag());
+
+  // If next message of WM_(SYS)KEYDOWN is WM_*CHAR message and the key
+  // combination is not reserved by the system, let's consume it now.
+  // TODO: We cannot initialize mCommittedCharsAndModifiers for VK_PACKET
+  //       if the message is WM_KEYUP because we don't have preceding
+  //       WM_CHAR message.
+  // TODO: Like Edge, we shouldn't dispatch two sets of keyboard events
+  //       for a Unicode character in non-BMP because its key value looks
+  //       broken and not good thing for our editor if only one keydown or
+  //       keypress event's default is prevented.  I guess, we should store
+  //       key message information globally and we should wait following
+  //       WM_KEYDOWN if following WM_CHAR is a part of a Unicode character.
+  if ((mMsg.message == WM_KEYDOWN || mMsg.message == WM_SYSKEYDOWN) &&
+      !IsReservedBySystem()) {
+    MSG charMsg;
+    while (GetFollowingCharMessage(charMsg)) {
+      // Although, got message shouldn't be WM_NULL in desktop apps,
+      // we should keep checking this.  FYI: This was added for Metrofox.
+      if (charMsg.message == WM_NULL) {
+        continue;
+      }
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::InitWithKeyOrChar(), removed char message, %s",
+               this, ToString(charMsg).get()));
+      Unused << NS_WARN_IF(charMsg.hwnd != mMsg.hwnd);
+      mFollowingCharMsgs.AppendElement(charMsg);
+    }
+    if (mFollowingCharMsgs.Length() == 1) {
+      // If we receive a keydown message for a high-surrogate, a low-surrogate
+      // keydown message **will** and should follow it.  We cannot translate the
+      // following WM_KEYDOWN message for the low-surrogate right now since
+      // it's not yet queued into the message queue yet.  Therefore, we need to
+      // wait next one to dispatch keypress event with setting its `.key` value
+      // to a surrogate pair rather than setting it to a lone surrogate.
+      // FYI: This may happen with typing a non-BMP character on the touch
+      // keyboard on Windows 10 or later except when an IME is installed. (If
+      // IME is installed, composition is used instead.)
+      if (IS_HIGH_SURROGATE(mFollowingCharMsgs[0].wParam)) {
+        if (pendingHighSurrogate) {
+          MOZ_LOG(gKeyLog, LogLevel::Warning,
+                  ("%p   NativeKey::InitWithKeyOrChar(), there is pending "
+                   "high surrogate input, but received another high surrogate "
+                   "input.  The previous one is discarded",
+                   this));
+        }
+        sPendingHighSurrogate = mFollowingCharMsgs[0].wParam;
+        mFollowingCharMsgs.Clear();
+      } else if (IS_LOW_SURROGATE(mFollowingCharMsgs[0].wParam)) {
+        // If we stopped dispathing a keypress event for a preceding
+        // high-surrogate, treat this keydown (for a low-surrogate) as
+        // introducing both the high surrogate and the low surrogate.
+        if (pendingHighSurrogate) {
+          MSG charMsg = mFollowingCharMsgs[0];
+          mFollowingCharMsgs[0].wParam = pendingHighSurrogate;
+          mFollowingCharMsgs.AppendElement(std::move(charMsg));
+        } else {
+          MOZ_LOG(
+              gKeyLog, LogLevel::Warning,
+              ("%p   NativeKey::InitWithKeyOrChar(), there is no pending high "
+               "surrogate input, but received lone low surrogate input",
+               this));
+        }
+      } else {
+        MOZ_LOG(gKeyLog, LogLevel::Warning,
+                ("%p   NativeKey::InitWithKeyOrChar(), there is pending "
+                 "high surrogate input, but received non-surrogate input.  "
+                 "The high surrogate input is discarded",
+                 this));
+      }
+    } else if (!mFollowingCharMsgs.IsEmpty()) {
+      MOZ_LOG(gKeyLog, LogLevel::Warning,
+              ("%p   NativeKey::InitWithKeyOrChar(), there is pending "
+               "high surrogate input, but received 2 or more character input.  "
+               "The high surrogate input is discarded",
+               this));
+    }
+  }
+
+  keyboardLayout->InitNativeKey(*this);
+
+  // Now, we can know if the key produces character(s) or a dead key with
+  // AltGraph modifier.  When user emulates AltGr key press with pressing
+  // both Ctrl and Alt and the key produces character(s) or a dead key, we
+  // need to replace Control and Alt state with AltGraph if the keyboard
+  // layout has AltGr key.
+  // Note that if Ctrl and/or Alt are pressed (not to emulate to press AltGr),
+  // we need to set actual modifiers to eKeyDown and eKeyUp.
+  if (MaybeEmulatingAltGraph() &&
+      (mCommittedCharsAndModifiers.IsProducingCharsWithAltGr() ||
+       mKeyNameIndex == KEY_NAME_INDEX_Dead)) {
+    mModKeyState.Unset(MODIFIER_CONTROL | MODIFIER_ALT);
+    mModKeyState.Set(MODIFIER_ALTGRAPH);
+  }
+
+  mIsDeadKey =
+      (IsFollowedByDeadCharMessage() ||
+       keyboardLayout->IsDeadKey(mOriginalVirtualKeyCode, mModKeyState));
+  mIsPrintableKey = mKeyNameIndex == KEY_NAME_INDEX_USE_STRING ||
+                    KeyboardLayout::IsPrintableCharKey(mOriginalVirtualKeyCode);
+  // The repeat count in mMsg.lParam isn't useful to check whether the event
+  // is caused by the auto-repeat feature because it's not incremented even
+  // if it's repeated twice or more (i.e., always 1).  Therefore, we need to
+  // check previous key state (31th bit) instead.  If it's 1, the key was down
+  // before the message was sent.
+  mIsRepeat = (mMsg.lParam & (1 << 30)) != 0;
+  InitIsSkippableForKeyOrChar(lastKeyMSG);
+
+  if (IsKeyDownMessage()) {
+    // Compute some strings which may be inputted by the key with various
+    // modifier state if this key event won't cause text input actually.
+    // They will be used for setting mAlternativeCharCodes in the callback
+    // method which will be called by TextEventDispatcher.
+    if (!IsFollowedByPrintableCharMessage()) {
+      ComputeInputtingStringWithKeyboardLayout();
+    }
+    // Remove odd char messages if there are.
+    RemoveFollowingOddCharMessages();
+  }
+}
+
+void NativeKey::InitCommittedCharsAndModifiersWithFollowingCharMessages() {
+  mCommittedCharsAndModifiers.Clear();
+  // This should cause inputting text in focused editor.  However, it
+  // ignores keypress events whose altKey or ctrlKey is true.
+  // Therefore, we need to remove these modifier state here.
+  Modifiers modifiers = mModKeyState.GetModifiers();
+  if (IsFollowedByPrintableCharMessage()) {
+    modifiers &= ~(MODIFIER_ALT | MODIFIER_CONTROL);
+    if (MaybeEmulatingAltGraph()) {
+      modifiers |= MODIFIER_ALTGRAPH;
+    }
+  }
+  // NOTE: This method assumes that WM_CHAR and WM_SYSCHAR are never retrieved
+  //       at same time.
+  for (size_t i = 0; i < mFollowingCharMsgs.Length(); ++i) {
+    // Ignore non-printable char messages.
+    if (!IsPrintableCharOrSysCharMessage(mFollowingCharMsgs[i])) {
+      continue;
+    }
+    char16_t ch = static_cast<char16_t>(mFollowingCharMsgs[i].wParam);
+    mCommittedCharsAndModifiers.Append(ch, modifiers);
+  }
+}
+
+NativeKey::~NativeKey() {
+  MOZ_LOG(gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::~NativeKey(), destroyed", this));
+  if (mIsOverridingKeyboardLayout) {
+    KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
+    keyboardLayout->RestoreLayout();
+  }
+  sLatestInstance = mLastInstance;
+}
+
+void NativeKey::InitWithAppCommand() {
+  if (GET_DEVICE_LPARAM(mMsg.lParam) != FAPPCOMMAND_KEY) {
+    return;
+  }
+
+  uint32_t appCommand = GET_APPCOMMAND_LPARAM(mMsg.lParam);
+  switch (GET_APPCOMMAND_LPARAM(mMsg.lParam)) {
+#undef NS_APPCOMMAND_TO_DOM_KEY_NAME_INDEX
+#define NS_APPCOMMAND_TO_DOM_KEY_NAME_INDEX(aAppCommand, aKeyNameIndex) \
+  case aAppCommand:                                                     \
+    mKeyNameIndex = aKeyNameIndex;                                      \
+    break;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_APPCOMMAND_TO_DOM_KEY_NAME_INDEX
+
+    default:
+      mKeyNameIndex = KEY_NAME_INDEX_Unidentified;
+  }
+
+  // Guess the virtual keycode which caused this message.
+  switch (appCommand) {
+    case APPCOMMAND_BROWSER_BACKWARD:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_BACK;
+      break;
+    case APPCOMMAND_BROWSER_FORWARD:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_FORWARD;
+      break;
+    case APPCOMMAND_BROWSER_REFRESH:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_REFRESH;
+      break;
+    case APPCOMMAND_BROWSER_STOP:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_STOP;
+      break;
+    case APPCOMMAND_BROWSER_SEARCH:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_SEARCH;
+      break;
+    case APPCOMMAND_BROWSER_FAVORITES:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_FAVORITES;
+      break;
+    case APPCOMMAND_BROWSER_HOME:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_BROWSER_HOME;
+      break;
+    case APPCOMMAND_VOLUME_MUTE:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_VOLUME_MUTE;
+      break;
+    case APPCOMMAND_VOLUME_DOWN:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_VOLUME_DOWN;
+      break;
+    case APPCOMMAND_VOLUME_UP:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_VOLUME_UP;
+      break;
+    case APPCOMMAND_MEDIA_NEXTTRACK:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_MEDIA_NEXT_TRACK;
+      break;
+    case APPCOMMAND_MEDIA_PREVIOUSTRACK:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_MEDIA_PREV_TRACK;
+      break;
+    case APPCOMMAND_MEDIA_STOP:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_MEDIA_STOP;
+      break;
+    case APPCOMMAND_MEDIA_PLAY_PAUSE:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_MEDIA_PLAY_PAUSE;
+      break;
+    case APPCOMMAND_LAUNCH_MAIL:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_LAUNCH_MAIL;
+      break;
+    case APPCOMMAND_LAUNCH_MEDIA_SELECT:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_LAUNCH_MEDIA_SELECT;
+      break;
+    case APPCOMMAND_LAUNCH_APP1:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_LAUNCH_APP1;
+      break;
+    case APPCOMMAND_LAUNCH_APP2:
+      mVirtualKeyCode = mOriginalVirtualKeyCode = VK_LAUNCH_APP2;
+      break;
+    default:
+      return;
+  }
+
+  uint16_t scanCodeEx = ComputeScanCodeExFromVirtualKeyCode(mVirtualKeyCode);
+  mScanCode = static_cast<uint8_t>(scanCodeEx & 0xFF);
+  uint8_t extended = static_cast<uint8_t>((scanCodeEx & 0xFF00) >> 8);
+  mIsExtended = (extended == 0xE0) || (extended == 0xE1);
+  mDOMKeyCode = KeyboardLayout::GetInstance()->ConvertNativeKeyCodeToDOMKeyCode(
+      mOriginalVirtualKeyCode);
+  mCodeNameIndex = KeyboardLayout::ConvertScanCodeToCodeNameIndex(
+      GetScanCodeWithExtendedFlag());
+  // If we can map the WM_APPCOMMAND to a virtual keycode, we can trust
+  // the result of GetKeyboardState().  Otherwise, we dispatch both
+  // keydown and keyup events from WM_APPCOMMAND handler.  Therefore,
+  // even if WM_APPCOMMAND is caused by auto key repeat, web apps receive
+  // a pair of DOM keydown and keyup events.  I.e., KeyboardEvent.repeat
+  // should be never true of such keys.
+  // XXX Isn't the key state always true?  If the key press caused this
+  //     WM_APPCOMMAND, that means it's pressed at that time.
+  if (mVirtualKeyCode) {
+    BYTE kbdState[256];
+    memset(kbdState, 0, sizeof(kbdState));
+    ::GetKeyboardState(kbdState);
+    mIsSkippableInRemoteProcess = mIsRepeat = !!kbdState[mVirtualKeyCode];
+  }
+}
+
+bool NativeKey::MaybeEmulatingAltGraph() const {
+  return IsControl() && IsAlt() && KeyboardLayout::GetInstance()->HasAltGr();
+}
+
+// static
+bool NativeKey::IsControlChar(char16_t aChar) {
+  static const char16_t U_SPACE = 0x20;
+  static const char16_t U_DELETE = 0x7F;
+  return aChar < U_SPACE || aChar == U_DELETE;
+}
+
+bool NativeKey::IsFollowedByDeadCharMessage() const {
+  if (mFollowingCharMsgs.IsEmpty()) {
+    return false;
+  }
+  return IsDeadCharMessage(mFollowingCharMsgs[0]);
+}
+
+bool NativeKey::IsFollowedByPrintableCharMessage() const {
+  for (size_t i = 0; i < mFollowingCharMsgs.Length(); ++i) {
+    if (IsPrintableCharMessage(mFollowingCharMsgs[i])) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool NativeKey::IsFollowedByPrintableCharOrSysCharMessage() const {
+  for (size_t i = 0; i < mFollowingCharMsgs.Length(); ++i) {
+    if (IsPrintableCharOrSysCharMessage(mFollowingCharMsgs[i])) {
+      return true;
+    }
+  }
+  return false;
+}
+
+bool NativeKey::IsReservedBySystem() const {
+  // Alt+Space key is handled by OS, we shouldn't touch it.
+  if (mModKeyState.IsAlt() && !mModKeyState.IsControl() &&
+      mVirtualKeyCode == VK_SPACE) {
+    return true;
+  }
+
+  // XXX How about Alt+F4? We receive WM_SYSKEYDOWN for F4 before closing the
+  //     window.  Although, we don't prevent to close the window but the key
+  //     event shouldn't be exposed to the web.
+
+  return false;
+}
+
+bool NativeKey::IsIMEDoingKakuteiUndo() const {
+  // Following message pattern is caused by "Kakutei-Undo" of ATOK or WXG:
+  // ---------------------------------------------------------------------------
+  // WM_KEYDOWN              * n (wParam = VK_BACK, lParam = 0x1)
+  // WM_KEYUP                * 1 (wParam = VK_BACK, lParam = 0xC0000001) # ATOK
+  // WM_IME_STARTCOMPOSITION * 1 (wParam = 0x0, lParam = 0x0)
+  // WM_IME_COMPOSITION      * 1 (wParam = 0x0, lParam = 0x1BF)
+  // WM_CHAR                 * n (wParam = VK_BACK, lParam = 0x1)
+  // WM_KEYUP                * 1 (wParam = VK_BACK, lParam = 0xC00E0001)
+  // ---------------------------------------------------------------------------
+  // This doesn't match usual key message pattern such as:
+  //   WM_KEYDOWN -> WM_CHAR -> WM_KEYDOWN -> WM_CHAR -> ... -> WM_KEYUP
+  // See following bugs for the detail.
+  // https://bugzilla.mozilla.gr.jp/show_bug.cgi?id=2885 (written in Japanese)
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=194559 (written in English)
+  MSG startCompositionMsg, compositionMsg, charMsg;
+  return WinUtils::PeekMessage(&startCompositionMsg, mMsg.hwnd,
+                               WM_IME_STARTCOMPOSITION, WM_IME_STARTCOMPOSITION,
+                               PM_NOREMOVE | PM_NOYIELD) &&
+         WinUtils::PeekMessage(&compositionMsg, mMsg.hwnd, WM_IME_COMPOSITION,
+                               WM_IME_COMPOSITION, PM_NOREMOVE | PM_NOYIELD) &&
+         WinUtils::PeekMessage(&charMsg, mMsg.hwnd, WM_CHAR, WM_CHAR,
+                               PM_NOREMOVE | PM_NOYIELD) &&
+         startCompositionMsg.wParam == 0x0 &&
+         startCompositionMsg.lParam == 0x0 && compositionMsg.wParam == 0x0 &&
+         compositionMsg.lParam == 0x1BF && charMsg.wParam == VK_BACK &&
+         charMsg.lParam == 0x1 &&
+         startCompositionMsg.time <= compositionMsg.time &&
+         compositionMsg.time <= charMsg.time;
+}
+
+void NativeKey::RemoveFollowingOddCharMessages() {
+  MOZ_ASSERT(IsKeyDownMessage());
+
+  // If the keydown message is synthesized for automated tests, there is
+  // nothing to do here.
+  if (mFakeCharMsgs) {
+    return;
+  }
+
+  // If there are some following char messages before another key message,
+  // there is nothing to do here.
+  if (!mFollowingCharMsgs.IsEmpty()) {
+    return;
+  }
+
+  // If the handling key isn't Backspace, there is nothing to do here.
+  if (mOriginalVirtualKeyCode != VK_BACK) {
+    return;
+  }
+
+  // If we don't see the odd message pattern, there is nothing to do here.
+  if (!IsIMEDoingKakuteiUndo()) {
+    return;
+  }
+
+  // Otherwise, we need to remove odd WM_CHAR messages for ATOK or WXG (both
+  // of them are Japanese IME).
+  MSG msg;
+  while (WinUtils::PeekMessage(&msg, mMsg.hwnd, WM_CHAR, WM_CHAR,
+                               PM_REMOVE | PM_NOYIELD)) {
+    if (msg.message != WM_CHAR) {
+      MOZ_RELEASE_ASSERT(msg.message == WM_NULL,
+                         "Unexpected message was removed");
+      continue;
+    }
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::RemoveFollowingOddCharMessages(), removed odd char "
+         "message, %s",
+         this, ToString(msg).get()));
+    mRemovedOddCharMsgs.AppendElement(msg);
+  }
+}
+
+UINT NativeKey::GetScanCodeWithExtendedFlag() const {
+  if (!mIsExtended) {
+    return mScanCode;
+  }
+  return (0xE000 | mScanCode);
+}
+
+uint32_t NativeKey::GetKeyLocation() const {
+  switch (mVirtualKeyCode) {
+    case VK_LSHIFT:
+    case VK_LCONTROL:
+    case VK_LMENU:
+    case VK_LWIN:
+      return eKeyLocationLeft;
+
+    case VK_RSHIFT:
+    case VK_RCONTROL:
+    case VK_RMENU:
+    case VK_RWIN:
+      return eKeyLocationRight;
+
+    case VK_RETURN:
+      // XXX This code assumes that all keyboard drivers use same mapping.
+      return !mIsExtended ? eKeyLocationStandard : eKeyLocationNumpad;
+
+    case VK_INSERT:
+    case VK_DELETE:
+    case VK_END:
+    case VK_DOWN:
+    case VK_NEXT:
+    case VK_LEFT:
+    case VK_CLEAR:
+    case VK_RIGHT:
+    case VK_HOME:
+    case VK_UP:
+    case VK_PRIOR:
+      // XXX This code assumes that all keyboard drivers use same mapping.
+      return mIsExtended ? eKeyLocationStandard : eKeyLocationNumpad;
+
+    // NumLock key isn't included due to IE9's behavior.
+    case VK_NUMPAD0:
+    case VK_NUMPAD1:
+    case VK_NUMPAD2:
+    case VK_NUMPAD3:
+    case VK_NUMPAD4:
+    case VK_NUMPAD5:
+    case VK_NUMPAD6:
+    case VK_NUMPAD7:
+    case VK_NUMPAD8:
+    case VK_NUMPAD9:
+    case VK_DECIMAL:
+    case VK_DIVIDE:
+    case VK_MULTIPLY:
+    case VK_SUBTRACT:
+    case VK_ADD:
+    // Separator key of Brazilian keyboard or JIS keyboard for Mac
+    case VK_ABNT_C2:
+      return eKeyLocationNumpad;
+
+    case VK_SHIFT:
+    case VK_CONTROL:
+    case VK_MENU:
+      NS_WARNING("Failed to decide the key location?");
+      [[fallthrough]];
+
+    default:
+      return eKeyLocationStandard;
+  }
+}
+
+uint8_t NativeKey::ComputeVirtualKeyCodeFromScanCode() const {
+  return static_cast<uint8_t>(
+      ::MapVirtualKeyEx(mScanCode, MAPVK_VSC_TO_VK, mKeyboardLayout));
+}
+
+uint8_t NativeKey::ComputeVirtualKeyCodeFromScanCodeEx() const {
+  // MapVirtualKeyEx() has been improved for supporting extended keys since
+  // Vista.  When we call it for mapping a scancode of an extended key and
+  // a virtual keycode, we need to add 0xE000 to the scancode.
+  return static_cast<uint8_t>(::MapVirtualKeyEx(
+      GetScanCodeWithExtendedFlag(), MAPVK_VSC_TO_VK_EX, mKeyboardLayout));
+}
+
+uint16_t NativeKey::ComputeScanCodeExFromVirtualKeyCode(
+    UINT aVirtualKeyCode) const {
+  return static_cast<uint16_t>(
+      ::MapVirtualKeyEx(aVirtualKeyCode, MAPVK_VK_TO_VSC_EX, mKeyboardLayout));
+}
+
+char16_t NativeKey::ComputeUnicharFromScanCode() const {
+  return static_cast<char16_t>(::MapVirtualKeyEx(
+      ComputeVirtualKeyCodeFromScanCode(), MAPVK_VK_TO_CHAR, mKeyboardLayout));
+}
+
+nsEventStatus NativeKey::InitKeyEvent(WidgetKeyboardEvent& aKeyEvent) const {
+  return InitKeyEvent(aKeyEvent, mModKeyState);
+}
+
+nsEventStatus NativeKey::InitKeyEvent(
+    WidgetKeyboardEvent& aKeyEvent,
+    const ModifierKeyState& aModKeyState) const {
+  if (mWidget->Destroyed()) {
+    MOZ_CRASH("NativeKey tries to dispatch a key event on destroyed widget");
+  }
+
+  LayoutDeviceIntPoint point(0, 0);
+  mWidget->InitEvent(aKeyEvent, &point);
+
+  switch (aKeyEvent.mMessage) {
+    case eKeyDown:
+      // If it was followed by a char message but it was consumed by somebody,
+      // we should mark it as consumed because somebody must have handled it
+      // and we should prevent to do "double action" for the key operation.
+      // However, for compatibility with older version and other browsers,
+      // we should dispatch the events even in the web content.
+      if (mCharMessageHasGone) {
+        aKeyEvent.PreventDefaultBeforeDispatch(CrossProcessForwarding::eAllow);
+      }
+      aKeyEvent.mKeyCode = mDOMKeyCode;
+      // Unique id for this keydown event and its associated keypress.
+      sUniqueKeyEventId++;
+      aKeyEvent.mUniqueId = sUniqueKeyEventId;
+      break;
+    case eKeyUp:
+      aKeyEvent.mKeyCode = mDOMKeyCode;
+      // Set defaultPrevented of the key event if the VK_MENU is not a system
+      // key release, so that the menu bar does not trigger.  This helps avoid
+      // triggering the menu bar for ALT key accelerators used in assistive
+      // technologies such as Window-Eyes and ZoomText or for switching open
+      // state of IME.  On the other hand, we should dispatch the events even
+      // in the web content for compatibility with older version and other
+      // browsers.
+      if (mOriginalVirtualKeyCode == VK_MENU && mMsg.message != WM_SYSKEYUP) {
+        aKeyEvent.PreventDefaultBeforeDispatch(CrossProcessForwarding::eAllow);
+      }
+      break;
+    case eKeyPress:
+      MOZ_ASSERT(!mCharMessageHasGone,
+                 "If following char message was consumed by somebody, "
+                 "keydown event should be consumed above");
+      aKeyEvent.mUniqueId = sUniqueKeyEventId;
+      break;
+    default:
+      MOZ_CRASH("Invalid event message");
+  }
+
+  aKeyEvent.mIsRepeat = mIsRepeat;
+  aKeyEvent.mMaybeSkippableInRemoteProcess = mIsSkippableInRemoteProcess;
+  aKeyEvent.mKeyNameIndex = mKeyNameIndex;
+  if (mKeyNameIndex == KEY_NAME_INDEX_USE_STRING) {
+    aKeyEvent.mKeyValue = mCommittedCharsAndModifiers.ToString();
+  }
+  aKeyEvent.mCodeNameIndex = mCodeNameIndex;
+  MOZ_ASSERT(mCodeNameIndex != CODE_NAME_INDEX_USE_STRING);
+  aKeyEvent.mLocation = GetKeyLocation();
+  aModKeyState.InitInputEvent(aKeyEvent);
+
+  KeyboardLayout::NotifyIdleServiceOfUserActivity();
+
+  MOZ_LOG(
+      gKeyLog, LogLevel::Info,
+      ("%p   NativeKey::InitKeyEvent(), initialized, aKeyEvent={ "
+       "mMessage=%s, mKeyNameIndex=%s, mKeyValue=\"%s\", mCodeNameIndex=%s, "
+       "mKeyCode=%s, mLocation=%s, mModifiers=%s, DefaultPrevented()=%s }",
+       this, ToChar(aKeyEvent.mMessage),
+       ToString(aKeyEvent.mKeyNameIndex).get(),
+       NS_ConvertUTF16toUTF8(aKeyEvent.mKeyValue).get(),
+       ToString(aKeyEvent.mCodeNameIndex).get(),
+       GetDOMKeyCodeName(aKeyEvent.mKeyCode).get(),
+       GetKeyLocationName(aKeyEvent.mLocation).get(),
+       GetModifiersName(aKeyEvent.mModifiers).get(),
+       GetBoolName(aKeyEvent.DefaultPrevented())));
+
+  return aKeyEvent.DefaultPrevented() ? nsEventStatus_eConsumeNoDefault
+                                      : nsEventStatus_eIgnore;
+}
+
+bool NativeKey::DispatchCommandEvent(uint32_t aEventCommand) const {
+  RefPtr<nsAtom> command;
+  switch (aEventCommand) {
+    case APPCOMMAND_BROWSER_BACKWARD:
+      command = nsGkAtoms::Back;
+      break;
+    case APPCOMMAND_BROWSER_FORWARD:
+      command = nsGkAtoms::Forward;
+      break;
+    case APPCOMMAND_BROWSER_REFRESH:
+      command = nsGkAtoms::Reload;
+      break;
+    case APPCOMMAND_BROWSER_STOP:
+      command = nsGkAtoms::Stop;
+      break;
+    case APPCOMMAND_BROWSER_SEARCH:
+      command = nsGkAtoms::Search;
+      break;
+    case APPCOMMAND_BROWSER_FAVORITES:
+      command = nsGkAtoms::Bookmarks;
+      break;
+    case APPCOMMAND_BROWSER_HOME:
+      command = nsGkAtoms::Home;
+      break;
+    case APPCOMMAND_CLOSE:
+      command = nsGkAtoms::Close;
+      break;
+    case APPCOMMAND_FIND:
+      command = nsGkAtoms::Find;
+      break;
+    case APPCOMMAND_HELP:
+      command = nsGkAtoms::Help;
+      break;
+    case APPCOMMAND_NEW:
+      command = nsGkAtoms::New;
+      break;
+    case APPCOMMAND_OPEN:
+      command = nsGkAtoms::Open;
+      break;
+    case APPCOMMAND_PRINT:
+      command = nsGkAtoms::Print;
+      break;
+    case APPCOMMAND_SAVE:
+      command = nsGkAtoms::Save;
+      break;
+    case APPCOMMAND_FORWARD_MAIL:
+      command = nsGkAtoms::ForwardMail;
+      break;
+    case APPCOMMAND_REPLY_TO_MAIL:
+      command = nsGkAtoms::ReplyToMail;
+      break;
+    case APPCOMMAND_SEND_MAIL:
+      command = nsGkAtoms::SendMail;
+      break;
+    case APPCOMMAND_MEDIA_NEXTTRACK:
+      command = nsGkAtoms::NextTrack;
+      break;
+    case APPCOMMAND_MEDIA_PREVIOUSTRACK:
+      command = nsGkAtoms::PreviousTrack;
+      break;
+    case APPCOMMAND_MEDIA_STOP:
+      command = nsGkAtoms::MediaStop;
+      break;
+    case APPCOMMAND_MEDIA_PLAY_PAUSE:
+      command = nsGkAtoms::PlayPause;
+      break;
+    default:
+      MOZ_LOG(
+          gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::DispatchCommandEvent(), doesn't dispatch command "
+           "event",
+           this));
+      return false;
+  }
+  WidgetCommandEvent appCommandEvent(true, command, mWidget);
+
+  mWidget->InitEvent(appCommandEvent);
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::DispatchCommandEvent(), dispatching "
+           "%s app command event...",
+           this, nsAtomCString(command).get()));
+  bool ok =
+      mWidget->DispatchWindowEvent(appCommandEvent) || mWidget->Destroyed();
+  MOZ_LOG(
+      gKeyLog, LogLevel::Info,
+      ("%p   NativeKey::DispatchCommandEvent(), dispatched app command event, "
+       "result=%s, mWidget->Destroyed()=%s",
+       this, GetBoolName(ok), GetBoolName(mWidget->Destroyed())));
+  return ok;
+}
+
+bool NativeKey::HandleAppCommandMessage() const {
+  // If the widget has gone, we should do nothing.
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::HandleAppCommandMessage(), WARNING, not handled "
+             "due to "
+             "destroyed the widget",
+             this));
+    return false;
+  }
+
+  // NOTE: Typical behavior of WM_APPCOMMAND caused by key is, WM_APPCOMMAND
+  //       message is _sent_ first.  Then, the DefaultWndProc will _post_
+  //       WM_KEYDOWN message and WM_KEYUP message if the keycode for the
+  //       command is available (i.e., mVirtualKeyCode is not 0).
+
+  // NOTE: IntelliType (Microsoft's keyboard utility software) always consumes
+  //       WM_KEYDOWN and WM_KEYUP.
+
+  // Let's dispatch keydown message before our chrome handles the command
+  // when the message is caused by a keypress.  This behavior makes handling
+  // WM_APPCOMMAND be a default action of the keydown event.  This means that
+  // web applications can handle multimedia keys and prevent our default action.
+  // This allow web applications to provide better UX for multimedia keyboard
+  // users.
+  bool dispatchKeyEvent = (GET_DEVICE_LPARAM(mMsg.lParam) == FAPPCOMMAND_KEY);
+  if (dispatchKeyEvent) {
+    // If a plug-in window has focus but it didn't consume the message, our
+    // window receive WM_APPCOMMAND message.  In this case, we shouldn't
+    // dispatch KeyboardEvents because an event handler may access the
+    // plug-in process synchronously.
+    dispatchKeyEvent =
+        WinUtils::IsOurProcessWindow(reinterpret_cast<HWND>(mMsg.wParam));
+  }
+
+  bool consumed = false;
+
+  if (dispatchKeyEvent) {
+    nsresult rv = mDispatcher->BeginNativeInputTransaction();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG(gKeyLog, LogLevel::Error,
+              ("%p   NativeKey::HandleAppCommandMessage(), FAILED due to "
+               "BeginNativeInputTransaction() failure",
+               this));
+      return true;
+    }
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleAppCommandMessage(), initializing keydown "
+             "event...",
+             this));
+    WidgetKeyboardEvent keydownEvent(true, eKeyDown, mWidget);
+    nsEventStatus status = InitKeyEvent(keydownEvent, mModKeyState);
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleAppCommandMessage(), tries to dispatch "
+             "keydown event...",
+             this));
+    // NOTE: If the keydown event is consumed by web contents, we shouldn't
+    //       continue to handle the command.
+    if (!mDispatcher->DispatchKeyboardEvent(eKeyDown, keydownEvent, status,
+                                            const_cast<NativeKey*>(this))) {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleAppCommandMessage(), keydown event isn't "
+               "dispatched",
+               this));
+      // If keyboard event wasn't fired, there must be composition.
+      // So, we don't need to dispatch a command event.
+      return true;
+    }
+    consumed = status == nsEventStatus_eConsumeNoDefault;
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleAppCommandMessage(), keydown event was "
+             "dispatched, consumed=%s",
+             this, GetBoolName(consumed)));
+    sDispatchedKeyOfAppCommand = mVirtualKeyCode;
+    if (mWidget->Destroyed()) {
+      MOZ_LOG(
+          gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleAppCommandMessage(), keydown event caused "
+           "destroying the widget",
+           this));
+      return true;
+    }
+  }
+
+  // Dispatch a command event or a content command event if the command is
+  // supported.
+  if (!consumed) {
+    uint32_t appCommand = GET_APPCOMMAND_LPARAM(mMsg.lParam);
+    EventMessage contentCommandMessage = eVoidEvent;
+    switch (appCommand) {
+      case APPCOMMAND_BROWSER_BACKWARD:
+      case APPCOMMAND_BROWSER_FORWARD:
+      case APPCOMMAND_BROWSER_REFRESH:
+      case APPCOMMAND_BROWSER_STOP:
+      case APPCOMMAND_BROWSER_SEARCH:
+      case APPCOMMAND_BROWSER_FAVORITES:
+      case APPCOMMAND_BROWSER_HOME:
+      case APPCOMMAND_CLOSE:
+      case APPCOMMAND_FIND:
+      case APPCOMMAND_HELP:
+      case APPCOMMAND_NEW:
+      case APPCOMMAND_OPEN:
+      case APPCOMMAND_PRINT:
+      case APPCOMMAND_SAVE:
+      case APPCOMMAND_FORWARD_MAIL:
+      case APPCOMMAND_REPLY_TO_MAIL:
+      case APPCOMMAND_SEND_MAIL:
+      case APPCOMMAND_MEDIA_NEXTTRACK:
+      case APPCOMMAND_MEDIA_PREVIOUSTRACK:
+      case APPCOMMAND_MEDIA_STOP:
+      case APPCOMMAND_MEDIA_PLAY_PAUSE:
+        // We shouldn't consume the message always because if we don't handle
+        // the message, the sender (typically, utility of keyboard or mouse)
+        // may send other key messages which indicate well known shortcut key.
+        consumed = DispatchCommandEvent(appCommand);
+        break;
+
+      // Use content command for following commands:
+      case APPCOMMAND_COPY:
+        contentCommandMessage = eContentCommandCopy;
+        break;
+      case APPCOMMAND_CUT:
+        contentCommandMessage = eContentCommandCut;
+        break;
+      case APPCOMMAND_PASTE:
+        contentCommandMessage = eContentCommandPaste;
+        break;
+      case APPCOMMAND_REDO:
+        contentCommandMessage = eContentCommandRedo;
+        break;
+      case APPCOMMAND_UNDO:
+        contentCommandMessage = eContentCommandUndo;
+        break;
+    }
+
+    if (contentCommandMessage) {
+      MOZ_ASSERT(!mWidget->Destroyed());
+      WidgetContentCommandEvent contentCommandEvent(true, contentCommandMessage,
+                                                    mWidget);
+      MOZ_LOG(
+          gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleAppCommandMessage(), dispatching %s event...",
+           this, ToChar(contentCommandMessage)));
+      mWidget->DispatchWindowEvent(contentCommandEvent);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleAppCommandMessage(), dispatched %s event",
+               this, ToChar(contentCommandMessage)));
+      consumed = true;
+
+      if (mWidget->Destroyed()) {
+        MOZ_LOG(gKeyLog, LogLevel::Info,
+                ("%p   NativeKey::HandleAppCommandMessage(), %s event caused "
+                 "destroying the widget",
+                 this, ToChar(contentCommandMessage)));
+        return true;
+      }
+    } else {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleAppCommandMessage(), doesn't dispatch "
+               "content "
+               "command event",
+               this));
+    }
+  }
+
+  // Dispatch a keyup event if the command is caused by pressing a key and
+  // the key isn't mapped to a virtual keycode.
+  if (dispatchKeyEvent && !mVirtualKeyCode) {
+    MOZ_ASSERT(!mWidget->Destroyed());
+    nsresult rv = mDispatcher->BeginNativeInputTransaction();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG(gKeyLog, LogLevel::Error,
+              ("%p   NativeKey::HandleAppCommandMessage(), FAILED due to "
+               "BeginNativeInputTransaction() failure",
+               this));
+      return true;
+    }
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleAppCommandMessage(), initializing keyup "
+             "event...",
+             this));
+    WidgetKeyboardEvent keyupEvent(true, eKeyUp, mWidget);
+    nsEventStatus status = InitKeyEvent(keyupEvent, mModKeyState);
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleAppCommandMessage(), dispatching keyup "
+             "event...",
+             this));
+    // NOTE: Ignore if the keyup event is consumed because keyup event
+    //       represents just a physical key event state change.
+    mDispatcher->DispatchKeyboardEvent(eKeyUp, keyupEvent, status,
+                                       const_cast<NativeKey*>(this));
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::HandleAppCommandMessage(), dispatched keyup event",
+         this));
+    if (mWidget->Destroyed()) {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleAppCommandMessage(), keyup event caused "
+               "destroying the widget",
+               this));
+      return true;
+    }
+  }
+
+  return consumed;
+}
+
+bool NativeKey::HandleKeyDownMessage(bool* aEventDispatched) const {
+  MOZ_ASSERT(IsKeyDownMessage());
+
+  if (aEventDispatched) {
+    *aEventDispatched = false;
+  }
+
+  if (sDispatchedKeyOfAppCommand &&
+      sDispatchedKeyOfAppCommand == mOriginalVirtualKeyCode) {
+    // The multimedia key event has already been dispatch from
+    // HandleAppCommandMessage().
+    sDispatchedKeyOfAppCommand = 0;
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), doesn't dispatch keydown "
+             "event due to already dispatched from HandleAppCommandMessage(), ",
+             this));
+    if (RedirectedKeyDownMessageManager::IsRedirectedMessage(mMsg)) {
+      RedirectedKeyDownMessageManager::Forget();
+    }
+    return true;
+  }
+
+  if (IsReservedBySystem()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), doesn't dispatch keydown "
+             "event because the key combination is reserved by the system",
+             this));
+    if (RedirectedKeyDownMessageManager::IsRedirectedMessage(mMsg)) {
+      RedirectedKeyDownMessageManager::Forget();
+    }
+    return false;
+  }
+
+  if (sPendingHighSurrogate) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), doesn't dispatch keydown "
+             "event because the key introduced only a high surrotate, so we "
+             "should wait the following low surrogate input",
+             this));
+    if (RedirectedKeyDownMessageManager::IsRedirectedMessage(mMsg)) {
+      RedirectedKeyDownMessageManager::Forget();
+    }
+    return false;
+  }
+
+  // If the widget has gone, we should do nothing.
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Warning,
+        ("%p   NativeKey::HandleKeyDownMessage(), WARNING, not handled due to "
+         "destroyed the widget",
+         this));
+    if (RedirectedKeyDownMessageManager::IsRedirectedMessage(mMsg)) {
+      RedirectedKeyDownMessageManager::Forget();
+    }
+    return false;
+  }
+
+  bool defaultPrevented = false;
+  if (mFakeCharMsgs ||
+      !RedirectedKeyDownMessageManager::IsRedirectedMessage(mMsg)) {
+    nsresult rv = mDispatcher->BeginNativeInputTransaction();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      MOZ_LOG(gKeyLog, LogLevel::Error,
+              ("%p   NativeKey::HandleKeyDownMessage(), FAILED due to "
+               "BeginNativeInputTransaction() failure",
+               this));
+      return true;
+    }
+
+    bool isIMEEnabled = WinUtils::IsIMEEnabled(mWidget->GetInputContext());
+
+    MOZ_LOG(gKeyLog, LogLevel::Debug,
+            ("%p   NativeKey::HandleKeyDownMessage(), initializing keydown "
+             "event...",
+             this));
+
+    WidgetKeyboardEvent keydownEvent(true, eKeyDown, mWidget);
+    nsEventStatus status = InitKeyEvent(keydownEvent, mModKeyState);
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::HandleKeyDownMessage(), dispatching keydown event...",
+         this));
+    bool dispatched = mDispatcher->DispatchKeyboardEvent(
+        eKeyDown, keydownEvent, status, const_cast<NativeKey*>(this));
+    if (aEventDispatched) {
+      *aEventDispatched = dispatched;
+    }
+    if (!dispatched) {
+      // If the keydown event wasn't fired, there must be composition.
+      // we don't need to do anything anymore.
+      MOZ_LOG(
+          gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleKeyDownMessage(), doesn't dispatch keypress "
+           "event(s) because keydown event isn't dispatched actually",
+           this));
+      return false;
+    }
+    defaultPrevented = status == nsEventStatus_eConsumeNoDefault;
+
+    if (mWidget->Destroyed() || IsFocusedWindowChanged()) {
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleKeyDownMessage(), keydown event caused "
+               "destroying the widget",
+               this));
+      return true;
+    }
+
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::HandleKeyDownMessage(), dispatched keydown event, "
+         "dispatched=%s, defaultPrevented=%s",
+         this, GetBoolName(dispatched), GetBoolName(defaultPrevented)));
+
+    // If IMC wasn't associated to the window but is associated it now (i.e.,
+    // focus is moved from a non-editable editor to an editor by keydown
+    // event handler), WM_CHAR and WM_SYSCHAR shouldn't cause first character
+    // inputting if IME is opened.  But then, we should redirect the native
+    // keydown message to IME.
+    // However, note that if focus has been already moved to another
+    // application, we shouldn't redirect the message to it because the keydown
+    // message is processed by us, so, nobody shouldn't process it.
+    HWND focusedWnd = ::GetFocus();
+    if (!defaultPrevented && !mFakeCharMsgs && focusedWnd && !isIMEEnabled &&
+        WinUtils::IsIMEEnabled(mWidget->GetInputContext())) {
+      RedirectedKeyDownMessageManager::RemoveNextCharMessage(focusedWnd);
+
+      INPUT keyinput;
+      keyinput.type = INPUT_KEYBOARD;
+      keyinput.ki.wVk = mOriginalVirtualKeyCode;
+      keyinput.ki.wScan = mScanCode;
+      keyinput.ki.dwFlags = KEYEVENTF_SCANCODE;
+      if (mIsExtended) {
+        keyinput.ki.dwFlags |= KEYEVENTF_EXTENDEDKEY;
+      }
+      keyinput.ki.time = 0;
+      keyinput.ki.dwExtraInfo = 0;
+
+      RedirectedKeyDownMessageManager::WillRedirect(mMsg, defaultPrevented);
+
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleKeyDownMessage(), redirecting %s...",
+               this, ToString(mMsg).get()));
+
+      ::SendInput(1, &keyinput, sizeof(keyinput));
+
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::HandleKeyDownMessage(), redirected %s", this,
+               ToString(mMsg).get()));
+
+      // Return here.  We shouldn't dispatch keypress event for this WM_KEYDOWN.
+      // If it's needed, it will be dispatched after next (redirected)
+      // WM_KEYDOWN.
+      return true;
+    }
+  } else {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), received a redirected %s",
+             this, ToString(mMsg).get()));
+
+    defaultPrevented = RedirectedKeyDownMessageManager::DefaultPrevented();
+    // If this is redirected keydown message, we have dispatched the keydown
+    // event already.
+    if (aEventDispatched) {
+      *aEventDispatched = true;
+    }
+  }
+
+  RedirectedKeyDownMessageManager::Forget();
+
+  MOZ_ASSERT(!mWidget->Destroyed());
+
+  // If the key was processed by IME and didn't cause WM_(SYS)CHAR messages, we
+  // shouldn't dispatch keypress event.
+  if (mOriginalVirtualKeyCode == VK_PROCESSKEY &&
+      !IsFollowedByPrintableCharOrSysCharMessage()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), not dispatching keypress "
+             "event because the key was already handled by IME, "
+             "defaultPrevented=%s",
+             this, GetBoolName(defaultPrevented)));
+    return defaultPrevented;
+  }
+
+  if (defaultPrevented) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), not dispatching keypress "
+             "event because preceding keydown event was consumed",
+             this));
+    return true;
+  }
+
+  MOZ_ASSERT(!mCharMessageHasGone,
+             "If following char message was consumed by somebody, "
+             "keydown event should have been consumed before dispatch");
+
+  // If mCommittedCharsAndModifiers was initialized with following char
+  // messages, we should dispatch keypress events with its information.
+  if (IsFollowedByPrintableCharOrSysCharMessage()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), tries to be dispatching "
+             "keypress events with retrieved char messages...",
+             this));
+    return DispatchKeyPressEventsWithRetrievedCharMessages();
+  }
+
+  // If we won't be getting a WM_CHAR, WM_SYSCHAR or WM_DEADCHAR, synthesize a
+  // keypress for almost all keys
+  if (NeedsToHandleWithoutFollowingCharMessages()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), tries to be dispatching "
+             "keypress events...",
+             this));
+    return DispatchKeyPressEventsWithoutCharMessage();
+  }
+
+  // If WM_KEYDOWN of VK_PACKET isn't followed by WM_CHAR, we don't need to
+  // dispatch keypress events.
+  if (mVirtualKeyCode == VK_PACKET) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), not dispatching keypress "
+             "event "
+             "because the key is VK_PACKET and there are no char messages",
+             this));
+    return false;
+  }
+
+  if (!mModKeyState.IsControl() && !mModKeyState.IsAlt() &&
+      !mModKeyState.IsWin() && mIsPrintableKey) {
+    // If this is simple KeyDown event but next message is not WM_CHAR,
+    // this event may not input text, so we should ignore this event.
+    // See bug 314130.
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), not dispatching keypress "
+             "event "
+             "because the key event is simple printable key's event but not "
+             "followed "
+             "by char messages",
+             this));
+    return false;
+  }
+
+  if (mIsDeadKey) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyDownMessage(), not dispatching keypress "
+             "event "
+             "because the key is a dead key and not followed by char messages",
+             this));
+    return false;
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleKeyDownMessage(), tries to be dispatching "
+           "keypress events due to no following char messages...",
+           this));
+  return DispatchKeyPressEventsWithoutCharMessage();
+}
+
+bool NativeKey::HandleCharMessage(bool* aEventDispatched) const {
+  MOZ_ASSERT(IsCharOrSysCharMessage(mMsg));
+  return HandleCharMessage(mMsg, aEventDispatched);
+}
+
+bool NativeKey::HandleCharMessage(const MSG& aCharMsg,
+                                  bool* aEventDispatched) const {
+  MOZ_ASSERT(IsKeyDownMessage() || IsCharOrSysCharMessage(mMsg));
+  MOZ_ASSERT(IsCharOrSysCharMessage(aCharMsg.message));
+
+  if (aEventDispatched) {
+    *aEventDispatched = false;
+  }
+
+  if ((IsCharOrSysCharMessage(mMsg) || IsEnterKeyPressCharMessage(mMsg)) &&
+      IsAnotherInstanceRemovingCharMessage()) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Warning,
+        ("%p   NativeKey::HandleCharMessage(), WARNING, does nothing because "
+         "the message should be handled in another instance removing this "
+         "message",
+         this));
+    // Consume this for now because it will be handled by another instance.
+    return true;
+  }
+
+  // If the key combinations is reserved by the system, we shouldn't dispatch
+  // eKeyPress event for it and passes the message to next wndproc.
+  if (IsReservedBySystem()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleCharMessage(), doesn't dispatch keypress "
+             "event because the key combination is reserved by the system",
+             this));
+    return false;
+  }
+
+  // If the widget has gone, we should do nothing.
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::HandleCharMessage(), WARNING, not handled due to "
+             "destroyed the widget",
+             this));
+    return false;
+  }
+
+  // When a control key is inputted by a key, it should be handled without
+  // WM_*CHAR messages at receiving WM_*KEYDOWN message.  So, when we receive
+  // WM_*CHAR message directly, we see a control character here.
+  // Note that when the char is '\r', it means that the char message should
+  // cause "Enter" keypress event for inserting a line break.
+  if (IsControlCharMessage(aCharMsg) && !IsEnterKeyPressCharMessage(aCharMsg)) {
+    // In this case, we don't need to dispatch eKeyPress event because:
+    // 1. We're the only browser which dispatches "keypress" event for
+    //    non-printable characters (Although, both Chrome and Edge dispatch
+    //    "keypress" event for some keys accidentally.  For example, "IntlRo"
+    //    key with Ctrl of Japanese keyboard layout).
+    // 2. Currently, we may handle shortcut keys with "keydown" event if
+    //    it's reserved or something.  So, we shouldn't dispatch "keypress"
+    //    event without it.
+    // Note that this does NOT mean we stop dispatching eKeyPress event for
+    // key presses causes a control character when Ctrl is pressed.  In such
+    // case, DispatchKeyPressEventsWithoutCharMessage() dispatches eKeyPress
+    // instead of this method.
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::HandleCharMessage(), doesn't dispatch keypress "
+         "event because received a control character input without WM_KEYDOWN",
+         this));
+    return false;
+  }
+
+  // XXXmnakano I think that if mMsg is WM_CHAR, i.e., it comes without
+  //            preceding WM_KEYDOWN, we should should dispatch composition
+  //            events instead of eKeyPress because they are not caused by
+  //            actual keyboard operation.
+
+  // First, handle normal text input or non-printable key case here.
+  WidgetKeyboardEvent keypressEvent(true, eKeyPress, mWidget);
+  if (IsEnterKeyPressCharMessage(aCharMsg)) {
+    keypressEvent.mKeyCode = NS_VK_RETURN;
+  } else {
+    keypressEvent.mCharCode = static_cast<uint32_t>(aCharMsg.wParam);
+  }
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gKeyLog, LogLevel::Error,
+            ("%p   NativeKey::HandleCharMessage(), FAILED due to "
+             "BeginNativeInputTransaction() failure",
+             this));
+    return true;
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::HandleCharMessage(), initializing keypress "
+           "event...",
+           this));
+
+  ModifierKeyState modKeyState(mModKeyState);
+  // When AltGr is pressed, both Alt and Ctrl are active.  However, when they
+  // are active, TextEditor won't treat the keypress event as inputting a
+  // character.  Therefore, when AltGr is pressed and the key tries to input
+  // a character, let's set them to false.
+  if (modKeyState.IsControl() && modKeyState.IsAlt() &&
+      IsPrintableCharMessage(aCharMsg)) {
+    modKeyState.Unset(MODIFIER_ALT | MODIFIER_CONTROL);
+  }
+  nsEventStatus status = InitKeyEvent(keypressEvent, modKeyState);
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleCharMessage(), dispatching keypress event...",
+           this));
+  bool dispatched = mDispatcher->MaybeDispatchKeypressEvents(
+      keypressEvent, status, const_cast<NativeKey*>(this));
+  if (aEventDispatched) {
+    *aEventDispatched = dispatched;
+  }
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleCharMessage(), keypress event caused "
+             "destroying the widget",
+             this));
+    return true;
+  }
+  bool consumed = status == nsEventStatus_eConsumeNoDefault;
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleCharMessage(), dispatched keypress event, "
+           "dispatched=%s, consumed=%s",
+           this, GetBoolName(dispatched), GetBoolName(consumed)));
+  return consumed;
+}
+
+bool NativeKey::HandleKeyUpMessage(bool* aEventDispatched) const {
+  MOZ_ASSERT(IsKeyUpMessage());
+
+  if (aEventDispatched) {
+    *aEventDispatched = false;
+  }
+
+  // If the key combinations is reserved by the system, we shouldn't dispatch
+  // eKeyUp event for it and passes the message to next wndproc.
+  if (IsReservedBySystem()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyUpMessage(), doesn't dispatch keyup "
+             "event because the key combination is reserved by the system",
+             this));
+    return false;
+  }
+
+  if (sPendingHighSurrogate) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyUpMessage(), doesn't dispatch keyup "
+             "event because the key introduced only a high surrotate, so we "
+             "should wait the following low surrogate input",
+             this));
+    return false;
+  }
+
+  // If the widget has gone, we should do nothing.
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Warning,
+        ("%p   NativeKey::HandleKeyUpMessage(), WARNING, not handled due to "
+         "destroyed the widget",
+         this));
+    return false;
+  }
+
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gKeyLog, LogLevel::Error,
+            ("%p   NativeKey::HandleKeyUpMessage(), FAILED due to "
+             "BeginNativeInputTransaction() failure",
+             this));
+    return true;
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::HandleKeyUpMessage(), initializing keyup event...",
+           this));
+  WidgetKeyboardEvent keyupEvent(true, eKeyUp, mWidget);
+  nsEventStatus status = InitKeyEvent(keyupEvent, mModKeyState);
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleKeyUpMessage(), dispatching keyup event...",
+           this));
+  bool dispatched = mDispatcher->DispatchKeyboardEvent(
+      eKeyUp, keyupEvent, status, const_cast<NativeKey*>(this));
+  if (aEventDispatched) {
+    *aEventDispatched = dispatched;
+  }
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::HandleKeyUpMessage(), keyup event caused "
+             "destroying the widget",
+             this));
+    return true;
+  }
+  bool consumed = status == nsEventStatus_eConsumeNoDefault;
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::HandleKeyUpMessage(), dispatched keyup event, "
+           "dispatched=%s, consumed=%s",
+           this, GetBoolName(dispatched), GetBoolName(consumed)));
+  return consumed;
+}
+
+bool NativeKey::NeedsToHandleWithoutFollowingCharMessages() const {
+  MOZ_ASSERT(IsKeyDownMessage());
+
+  // If the key combination is reserved by the system, the caller shouldn't
+  // do anything with following WM_*CHAR messages.  So, let's return true here.
+  if (IsReservedBySystem()) {
+    return true;
+  }
+
+  // If the keydown message is generated for inputting some Unicode characters
+  // via SendInput() API, we need to handle it only with WM_*CHAR messages.
+  if (mVirtualKeyCode == VK_PACKET) {
+    return false;
+  }
+
+  // If following char message is for a control character, it should be handled
+  // without WM_CHAR message.  This is typically Ctrl + [a-z].
+  if (mFollowingCharMsgs.Length() == 1 &&
+      IsControlCharMessage(mFollowingCharMsgs[0])) {
+    return true;
+  }
+
+  // If keydown message is followed by WM_CHAR or WM_SYSCHAR whose wParam isn't
+  // a control character, we should dispatch keypress event with the char
+  // message even with any modifier state.
+  if (IsFollowedByPrintableCharOrSysCharMessage()) {
+    return false;
+  }
+
+  // If any modifier keys which may cause printable keys becoming non-printable
+  // are not pressed, we don't need special handling for the key.
+  // Note that if the key does not produce a character with AltGr and when
+  // AltGr key is pressed, we don't need to dispatch eKeyPress event for it
+  // because AltGr shouldn't be used for a modifier for a shortcut without
+  // Ctrl, Alt or Win.  That means that we should treat it in same path for
+  // Shift key.
+  if (!mModKeyState.IsControl() && !mModKeyState.IsAlt() &&
+      !mModKeyState.IsWin()) {
+    return false;
+  }
+
+  // If the key event causes dead key event, we don't need to dispatch keypress
+  // event.
+  if (mIsDeadKey && mCommittedCharsAndModifiers.IsEmpty()) {
+    return false;
+  }
+
+  // Even if the key is a printable key, it might cause non-printable character
+  // input with modifier key(s).
+  return mIsPrintableKey;
+}
+
+static nsCString GetResultOfInSendMessageEx() {
+  DWORD ret = ::InSendMessageEx(nullptr);
+  if (!ret) {
+    return "ISMEX_NOSEND"_ns;
+  }
+  nsCString result;
+  if (ret & ISMEX_CALLBACK) {
+    result = "ISMEX_CALLBACK";
+  }
+  if (ret & ISMEX_NOTIFY) {
+    if (!result.IsEmpty()) {
+      result += " | ";
+    }
+    result += "ISMEX_NOTIFY";
+  }
+  if (ret & ISMEX_REPLIED) {
+    if (!result.IsEmpty()) {
+      result += " | ";
+    }
+    result += "ISMEX_REPLIED";
+  }
+  if (ret & ISMEX_SEND) {
+    if (!result.IsEmpty()) {
+      result += " | ";
+    }
+    result += "ISMEX_SEND";
+  }
+  return result;
+}
+
+bool NativeKey::MayBeSameCharMessage(const MSG& aCharMsg1,
+                                     const MSG& aCharMsg2) const {
+  // NOTE: Although, we don't know when this case occurs, the scan code value
+  //       in lParam may be changed from 0 to something.  The changed value
+  //       is different from the scan code of handling keydown message.
+  static const LPARAM kScanCodeMask = 0x00FF0000;
+  return aCharMsg1.message == aCharMsg2.message &&
+         aCharMsg1.wParam == aCharMsg2.wParam &&
+         (aCharMsg1.lParam & ~kScanCodeMask) ==
+             (aCharMsg2.lParam & ~kScanCodeMask);
+}
+
+bool NativeKey::IsSamePhysicalKeyMessage(const MSG& aKeyOrCharMsg1,
+                                         const MSG& aKeyOrCharMsg2) const {
+  if (NS_WARN_IF(aKeyOrCharMsg1.message < WM_KEYFIRST) ||
+      NS_WARN_IF(aKeyOrCharMsg1.message > WM_KEYLAST) ||
+      NS_WARN_IF(aKeyOrCharMsg2.message < WM_KEYFIRST) ||
+      NS_WARN_IF(aKeyOrCharMsg2.message > WM_KEYLAST)) {
+    return false;
+  }
+  return WinUtils::GetScanCode(aKeyOrCharMsg1.lParam) ==
+             WinUtils::GetScanCode(aKeyOrCharMsg2.lParam) &&
+         WinUtils::IsExtendedScanCode(aKeyOrCharMsg1.lParam) ==
+             WinUtils::IsExtendedScanCode(aKeyOrCharMsg2.lParam);
+}
+
+bool NativeKey::GetFollowingCharMessage(MSG& aCharMsg) {
+  MOZ_ASSERT(IsKeyDownMessage());
+
+  aCharMsg.message = WM_NULL;
+
+  if (mFakeCharMsgs) {
+    for (size_t i = 0; i < mFakeCharMsgs->Length(); i++) {
+      FakeCharMsg& fakeCharMsg = mFakeCharMsgs->ElementAt(i);
+      if (fakeCharMsg.mConsumed) {
+        continue;
+      }
+      MSG charMsg = fakeCharMsg.GetCharMsg(mMsg.hwnd);
+      fakeCharMsg.mConsumed = true;
+      if (!IsCharMessage(charMsg)) {
+        return false;
+      }
+      aCharMsg = charMsg;
+      return true;
+    }
+    return false;
+  }
+
+  // If next key message is not char message, we should give up to find a
+  // related char message for the handling keydown event for now.
+  // Note that it's possible other applications may send other key message
+  // after we call TranslateMessage(). That may cause PeekMessage() failing
+  // to get char message for the handling keydown message.
+  MSG nextKeyMsg;
+  if (!WinUtils::PeekMessage(&nextKeyMsg, mMsg.hwnd, WM_KEYFIRST, WM_KEYLAST,
+                             PM_NOREMOVE | PM_NOYIELD) ||
+      !IsCharMessage(nextKeyMsg)) {
+    MOZ_LOG(gKeyLog, LogLevel::Debug,
+            ("%p   NativeKey::GetFollowingCharMessage(), there are no char "
+             "messages",
+             this));
+    return false;
+  }
+  const MSG kFoundCharMsg = nextKeyMsg;
+
+  AutoRestore<MSG> saveLastRemovingMsg(mRemovingMsg);
+  mRemovingMsg = nextKeyMsg;
+
+  mReceivedMsg = sEmptyMSG;
+  AutoRestore<MSG> ensureToClearRecivedMsg(mReceivedMsg);
+
+  // On Metrofox, PeekMessage() sometimes returns WM_NULL even if we specify
+  // the message range.  So, if it returns WM_NULL, we should retry to get
+  // the following char message it was found above.
+  for (uint32_t i = 0; i < 50; i++) {
+    MSG removedMsg, nextKeyMsgInAllWindows;
+    bool doCrash = false;
+    if (!WinUtils::PeekMessage(&removedMsg, mMsg.hwnd, nextKeyMsg.message,
+                               nextKeyMsg.message, PM_REMOVE | PM_NOYIELD)) {
+      // We meets unexpected case.  We should collect the message queue state
+      // and crash for reporting the bug.
+      doCrash = true;
+
+      // If another instance was created for the removing message during trying
+      // to remove a char message, the instance didn't handle it for preventing
+      // recursive handling.  So, let's handle it in this instance.
+      if (!IsEmptyMSG(mReceivedMsg)) {
+        // If focus is moved to different window, we shouldn't handle it on
+        // the widget.  Let's discard it for now.
+        if (mReceivedMsg.hwnd != nextKeyMsg.hwnd) {
+          MOZ_LOG(
+              gKeyLog, LogLevel::Warning,
+              ("%p   NativeKey::GetFollowingCharMessage(), WARNING, received a "
+               "char message during removing it from the queue, but it's for "
+               "different window, mReceivedMsg=%s, nextKeyMsg=%s, "
+               "kFoundCharMsg=%s",
+               this, ToString(mReceivedMsg).get(), ToString(nextKeyMsg).get(),
+               ToString(kFoundCharMsg).get()));
+          // There might still exist char messages, the loop of calling
+          // this method should be continued.
+          aCharMsg.message = WM_NULL;
+          return true;
+        }
+        // Even if the received message is different from what we tried to
+        // remove from the queue, let's take the received message as a part of
+        // the result of this key sequence.
+        if (mReceivedMsg.message != nextKeyMsg.message ||
+            mReceivedMsg.wParam != nextKeyMsg.wParam ||
+            mReceivedMsg.lParam != nextKeyMsg.lParam) {
+          MOZ_LOG(
+              gKeyLog, LogLevel::Warning,
+              ("%p   NativeKey::GetFollowingCharMessage(), WARNING, received a "
+               "char message during removing it from the queue, but it's "
+               "differnt from what trying to remove from the queue, "
+               "aCharMsg=%s, nextKeyMsg=%s, kFoundCharMsg=%s",
+               this, ToString(mReceivedMsg).get(), ToString(nextKeyMsg).get(),
+               ToString(kFoundCharMsg).get()));
+        } else {
+          MOZ_LOG(
+              gKeyLog, LogLevel::Debug,
+              ("%p   NativeKey::GetFollowingCharMessage(), succeeded to "
+               "retrieve next char message via another instance, aCharMsg=%s, "
+               "kFoundCharMsg=%s",
+               this, ToString(mReceivedMsg).get(),
+               ToString(kFoundCharMsg).get()));
+        }
+        aCharMsg = mReceivedMsg;
+        return true;
+      }
+
+      // The char message is redirected to different thread's window by focus
+      // move or something or just cancelled by external application.
+      if (!WinUtils::PeekMessage(&nextKeyMsgInAllWindows, 0, WM_KEYFIRST,
+                                 WM_KEYLAST, PM_NOREMOVE | PM_NOYIELD)) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message, but it's already gone from all message "
+             "queues, nextKeyMsg=%s, kFoundCharMsg=%s",
+             this, ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        return true;  // XXX should return false in this case
+      }
+      // The next key message is redirected to different window created by our
+      // thread, we should do nothing because we must not have focus.
+      if (nextKeyMsgInAllWindows.hwnd != mMsg.hwnd) {
+        aCharMsg = nextKeyMsgInAllWindows;
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message, but found in another message queue, "
+             "nextKeyMsgInAllWindows=%s, nextKeyMsg=%s, kFoundCharMsg=%s",
+             this, ToString(nextKeyMsgInAllWindows).get(),
+             ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        return true;
+      }
+      // If next key message becomes non-char message, this key operation
+      // may have already been consumed or canceled.
+      if (!IsCharMessage(nextKeyMsgInAllWindows)) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message and next key message becomes non-char "
+             "message, nextKeyMsgInAllWindows=%s, nextKeyMsg=%s, "
+             "kFoundCharMsg=%s",
+             this, ToString(nextKeyMsgInAllWindows).get(),
+             ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        MOZ_ASSERT(!mCharMessageHasGone);
+        mFollowingCharMsgs.Clear();
+        mCharMessageHasGone = true;
+        return false;
+      }
+      // If next key message is still a char message but different key message,
+      // we should treat current key operation is consumed or canceled and
+      // next char message should be handled as an orphan char message later.
+      if (!IsSamePhysicalKeyMessage(nextKeyMsgInAllWindows, kFoundCharMsg)) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message and next key message becomes differnt "
+             "key's "
+             "char message, nextKeyMsgInAllWindows=%s, nextKeyMsg=%s, "
+             "kFoundCharMsg=%s",
+             this, ToString(nextKeyMsgInAllWindows).get(),
+             ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        MOZ_ASSERT(!mCharMessageHasGone);
+        mFollowingCharMsgs.Clear();
+        mCharMessageHasGone = true;
+        return false;
+      }
+      // If next key message is still a char message but the message is changed,
+      // we should retry to remove the new message with PeekMessage() again.
+      if (nextKeyMsgInAllWindows.message != nextKeyMsg.message) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message due to message change, let's retry to "
+             "remove the message with newly found char message, "
+             "nextKeyMsgInAllWindows=%s, nextKeyMsg=%s, kFoundCharMsg=%s",
+             this, ToString(nextKeyMsgInAllWindows).get(),
+             ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        nextKeyMsg = nextKeyMsgInAllWindows;
+        continue;
+      }
+      // If there is still existing a char message caused by same physical key
+      // in the queue but PeekMessage(PM_REMOVE) failed to remove it from the
+      // queue, it might be possible that the odd keyboard layout or utility
+      // hooks only PeekMessage(PM_NOREMOVE) and GetMessage().  So, let's try
+      // remove the char message with GetMessage() again.
+      // FYI: The wParam might be different from the found message, but it's
+      //      okay because we assume that odd keyboard layouts return actual
+      //      inputting character at removing the char message.
+      if (WinUtils::GetMessage(&removedMsg, mMsg.hwnd, nextKeyMsg.message,
+                               nextKeyMsg.message)) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message, but succeeded with GetMessage(), "
+             "removedMsg=%s, kFoundCharMsg=%s",
+             this, ToString(removedMsg).get(), ToString(kFoundCharMsg).get()));
+        // Cancel to crash, but we need to check the removed message value.
+        doCrash = false;
+      }
+      // If we've already removed some WM_NULL messages from the queue and
+      // the found message has already gone from the queue, let's treat the key
+      // as inputting no characters and already consumed.
+      else if (i > 0) {
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message, but removed %d WM_NULL messages",
+             this, i));
+        // If the key is a printable key or a control key but tried to input
+        // a character, mark mCharMessageHasGone true for handling the keydown
+        // event as inputting empty string.
+        MOZ_ASSERT(!mCharMessageHasGone);
+        mFollowingCharMsgs.Clear();
+        mCharMessageHasGone = true;
+        return false;
+      }
+      MOZ_LOG(gKeyLog, LogLevel::Error,
+              ("%p   NativeKey::GetFollowingCharMessage(), FAILED, lost target "
+               "message to remove, nextKeyMsg=%s",
+               this, ToString(nextKeyMsg).get()));
+    }
+
+    if (doCrash) {
+      nsPrintfCString info(
+          "\nPeekMessage() failed to remove char message! "
+          "\nActive keyboard layout=0x%p (%s), "
+          "\nHandling message: %s, InSendMessageEx()=%s, "
+          "\nFound message: %s, "
+          "\nWM_NULL has been removed: %d, "
+          "\nNext key message in all windows: %s, "
+          "time=%ld, ",
+          KeyboardLayout::GetInstance()->GetLoadedLayout(),
+          KeyboardLayout::GetInstance()->GetLoadedLayoutName().get(),
+          ToString(mMsg).get(), GetResultOfInSendMessageEx().get(),
+          ToString(kFoundCharMsg).get(), i,
+          ToString(nextKeyMsgInAllWindows).get(), nextKeyMsgInAllWindows.time);
+      CrashReporter::AppendAppNotesToCrashReport(info);
+      MSG nextMsg;
+      if (WinUtils::PeekMessage(&nextMsg, 0, 0, 0, PM_NOREMOVE | PM_NOYIELD)) {
+        nsPrintfCString info("\nNext message in all windows: %s, time=%ld",
+                             ToString(nextMsg).get(), nextMsg.time);
+        CrashReporter::AppendAppNotesToCrashReport(info);
+      } else {
+        CrashReporter::AppendAppNotesToCrashReport(
+            "\nThere is no message in any window"_ns);
+      }
+
+      MOZ_CRASH("We lost the following char message");
+    }
+
+    // We're still not sure why ::PeekMessage() may return WM_NULL even with
+    // its first message and its last message are same message.  However,
+    // at developing Metrofox, we met this case even with usual keyboard
+    // layouts.  So, it might be possible in desktop application or it really
+    // occurs with some odd keyboard layouts which perhaps hook API.
+    if (removedMsg.message == WM_NULL) {
+      MOZ_LOG(gKeyLog, LogLevel::Warning,
+              ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+               "remove a char message, instead, removed WM_NULL message, "
+               "removedMsg=%s",
+               this, ToString(removedMsg).get()));
+      // Check if there is the message which we're trying to remove.
+      MSG newNextKeyMsg;
+      if (!WinUtils::PeekMessage(&newNextKeyMsg, mMsg.hwnd, WM_KEYFIRST,
+                                 WM_KEYLAST, PM_NOREMOVE | PM_NOYIELD)) {
+        // If there is no key message, we should mark this keydown as consumed
+        // because the key operation may have already been handled or canceled.
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message because it's gone during removing it from "
+             "the queue, nextKeyMsg=%s, kFoundCharMsg=%s",
+             this, ToString(nextKeyMsg).get(), ToString(kFoundCharMsg).get()));
+        MOZ_ASSERT(!mCharMessageHasGone);
+        mFollowingCharMsgs.Clear();
+        mCharMessageHasGone = true;
+        return false;
+      }
+      if (!IsCharMessage(newNextKeyMsg)) {
+        // If next key message becomes a non-char message, we should mark this
+        // keydown as consumed because the key operation may have already been
+        // handled or canceled.
+        MOZ_LOG(
+            gKeyLog, LogLevel::Warning,
+            ("%p   NativeKey::GetFollowingCharMessage(), WARNING, failed to "
+             "remove a char message because it's gone during removing it from "
+             "the queue, nextKeyMsg=%s, newNextKeyMsg=%s, kFoundCharMsg=%s",
+             this, ToString(nextKeyMsg).get(), ToString(newNextKeyMsg).get(),
+             ToString(kFoundCharMsg).get()));
+        MOZ_ASSERT(!mCharMessageHasGone);
+        mFollowingCharMsgs.Clear();
+        mCharMessageHasGone = true;
+        return false;
+      }
+      MOZ_LOG(
+          gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::GetFollowingCharMessage(), there is the message "
+           "which is being tried to be removed from the queue, trying again...",
+           this));
+      continue;
+    }
+
+    // Typically, this case occurs with WM_DEADCHAR.  If the removed message's
+    // wParam becomes 0, that means that the key event shouldn't cause text
+    // input.  So, let's ignore the strange char message.
+    if (removedMsg.message == nextKeyMsg.message && !removedMsg.wParam) {
+      MOZ_LOG(
+          gKeyLog, LogLevel::Warning,
+          ("%p   NativeKey::GetFollowingCharMessage(), WARNING, succeeded to "
+           "remove a char message, but the removed message's wParam is 0, "
+           "removedMsg=%s",
+           this, ToString(removedMsg).get()));
+      return false;
+    }
+
+    // This is normal case.
+    if (MayBeSameCharMessage(removedMsg, nextKeyMsg)) {
+      aCharMsg = removedMsg;
+      MOZ_LOG(
+          gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::GetFollowingCharMessage(), succeeded to retrieve "
+           "next char message, aCharMsg=%s",
+           this, ToString(aCharMsg).get()));
+      return true;
+    }
+
+    // Even if removed message is different char message from the found char
+    // message, when the scan code is same, we can assume that the message
+    // is overwritten by somebody who hooks API.  See bug 1336028 comment 0 for
+    // the possible scenarios.
+    if (IsCharMessage(removedMsg) &&
+        IsSamePhysicalKeyMessage(removedMsg, nextKeyMsg)) {
+      aCharMsg = removedMsg;
+      MOZ_LOG(
+          gKeyLog, LogLevel::Warning,
+          ("%p   NativeKey::GetFollowingCharMessage(), WARNING, succeeded to "
+           "remove a char message, but the removed message was changed from "
+           "the found message except their scancode, aCharMsg=%s, "
+           "nextKeyMsg=%s, kFoundCharMsg=%s",
+           this, ToString(aCharMsg).get(), ToString(nextKeyMsg).get(),
+           ToString(kFoundCharMsg).get()));
+      return true;
+    }
+
+    // When found message's wParam is 0 and its scancode is 0xFF, we may remove
+    // usual char message actually.  In such case, we should use the removed
+    // char message.
+    if (IsCharMessage(removedMsg) && !nextKeyMsg.wParam &&
+        WinUtils::GetScanCode(nextKeyMsg.lParam) == 0xFF) {
+      aCharMsg = removedMsg;
+      MOZ_LOG(
+          gKeyLog, LogLevel::Warning,
+          ("%p   NativeKey::GetFollowingCharMessage(), WARNING, succeeded to "
+           "remove a char message, but the removed message was changed from "
+           "the found message but the found message was odd, so, ignoring the "
+           "odd found message and respecting the removed message, aCharMsg=%s, "
+           "nextKeyMsg=%s, kFoundCharMsg=%s",
+           this, ToString(aCharMsg).get(), ToString(nextKeyMsg).get(),
+           ToString(kFoundCharMsg).get()));
+      return true;
+    }
+
+    // NOTE: Although, we don't know when this case occurs, the scan code value
+    //       in lParam may be changed from 0 to something.  The changed value
+    //       is different from the scan code of handling keydown message.
+    MOZ_LOG(
+        gKeyLog, LogLevel::Error,
+        ("%p   NativeKey::GetFollowingCharMessage(), FAILED, removed message "
+         "is really different from what we have already found, removedMsg=%s, "
+         "nextKeyMsg=%s, kFoundCharMsg=%s",
+         this, ToString(removedMsg).get(), ToString(nextKeyMsg).get(),
+         ToString(kFoundCharMsg).get()));
+    nsPrintfCString info(
+        "\nPeekMessage() removed unexpcted char message! "
+        "\nActive keyboard layout=0x%p (%s), "
+        "\nHandling message: %s, InSendMessageEx()=%s, "
+        "\nFound message: %s, "
+        "\nRemoved message: %s, ",
+        KeyboardLayout::GetInstance()->GetLoadedLayout(),
+        KeyboardLayout::GetInstance()->GetLoadedLayoutName().get(),
+        ToString(mMsg).get(), GetResultOfInSendMessageEx().get(),
+        ToString(kFoundCharMsg).get(), ToString(removedMsg).get());
+    CrashReporter::AppendAppNotesToCrashReport(info);
+    // What's the next key message?
+    MSG nextKeyMsgAfter;
+    if (WinUtils::PeekMessage(&nextKeyMsgAfter, mMsg.hwnd, WM_KEYFIRST,
+                              WM_KEYLAST, PM_NOREMOVE | PM_NOYIELD)) {
+      nsPrintfCString info(
+          "\nNext key message after unexpected char message "
+          "removed: %s, ",
+          ToString(nextKeyMsgAfter).get());
+      CrashReporter::AppendAppNotesToCrashReport(info);
+    } else {
+      CrashReporter::AppendAppNotesToCrashReport(
+          nsLiteralCString("\nThere is no key message after unexpected char "
+                           "message removed, "));
+    }
+    // Another window has a key message?
+    if (WinUtils::PeekMessage(&nextKeyMsgInAllWindows, 0, WM_KEYFIRST,
+                              WM_KEYLAST, PM_NOREMOVE | PM_NOYIELD)) {
+      nsPrintfCString info("\nNext key message in all windows: %s.",
+                           ToString(nextKeyMsgInAllWindows).get());
+      CrashReporter::AppendAppNotesToCrashReport(info);
+    } else {
+      CrashReporter::AppendAppNotesToCrashReport(
+          "\nThere is no key message in any windows."_ns);
+    }
+
+    MOZ_CRASH("PeekMessage() removed unexpected message");
+  }
+  MOZ_LOG(
+      gKeyLog, LogLevel::Error,
+      ("%p   NativeKey::GetFollowingCharMessage(), FAILED, removed messages "
+       "are all WM_NULL, nextKeyMsg=%s",
+       this, ToString(nextKeyMsg).get()));
+  nsPrintfCString info(
+      "\nWe lost following char message! "
+      "\nActive keyboard layout=0x%p (%s), "
+      "\nHandling message: %s, InSendMessageEx()=%s, \n"
+      "Found message: %s, removed a lot of WM_NULL",
+      KeyboardLayout::GetInstance()->GetLoadedLayout(),
+      KeyboardLayout::GetInstance()->GetLoadedLayoutName().get(),
+      ToString(mMsg).get(), GetResultOfInSendMessageEx().get(),
+      ToString(kFoundCharMsg).get());
+  CrashReporter::AppendAppNotesToCrashReport(info);
+  MOZ_CRASH("We lost the following char message");
+  return false;
+}
+
+void NativeKey::ComputeInputtingStringWithKeyboardLayout() {
+  KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
+
+  if (KeyboardLayout::IsPrintableCharKey(mVirtualKeyCode) ||
+      mCharMessageHasGone) {
+    mInputtingStringAndModifiers = mCommittedCharsAndModifiers;
+  } else {
+    mInputtingStringAndModifiers.Clear();
+  }
+  mShiftedString.Clear();
+  mUnshiftedString.Clear();
+  mShiftedLatinChar = mUnshiftedLatinChar = 0;
+
+  // XXX How about when Win key is pressed?
+  if (!mModKeyState.IsControl() && !mModKeyState.IsAlt()) {
+    return;
+  }
+
+  // If user is inputting a Unicode character with typing Alt + Numpad
+  // keys, we shouldn't set alternative key codes because the key event
+  // shouldn't match with a mnemonic.  However, we should set only
+  // mUnshiftedString for keeping traditional behavior at WM_SYSKEYDOWN.
+  // FYI: I guess that it's okay that mUnshiftedString stays empty.  So,
+  //      if its value breaks something, you must be able to just return here.
+  if (MaybeTypingUnicodeScalarValue()) {
+    if (!mCommittedCharsAndModifiers.IsEmpty()) {
+      MOZ_ASSERT(mMsg.message == WM_SYSKEYDOWN);
+      char16_t num = mCommittedCharsAndModifiers.CharAt(0);
+      MOZ_ASSERT(num >= '0' && num <= '9');
+      mUnshiftedString.Append(num, MODIFIER_NONE);
+      return;
+    }
+    // If user presses a function key without NumLock or 3rd party utility
+    // synthesizes a function key on numpad, we should handle it as-is because
+    // the user's intention may be performing `Alt` + foo.
+    MOZ_ASSERT(!KeyboardLayout::IsPrintableCharKey(mVirtualKeyCode));
+    return;
+  }
+
+  ModifierKeyState capsLockState(mModKeyState.GetModifiers() &
+                                 MODIFIER_CAPSLOCK);
+
+  mUnshiftedString =
+      keyboardLayout->GetUniCharsAndModifiers(mVirtualKeyCode, capsLockState);
+  capsLockState.Set(MODIFIER_SHIFT);
+  mShiftedString =
+      keyboardLayout->GetUniCharsAndModifiers(mVirtualKeyCode, capsLockState);
+
+  // The current keyboard cannot input alphabets or numerics,
+  // we should append them for Shortcut/Access keys.
+  // E.g., for Cyrillic keyboard layout.
+  capsLockState.Unset(MODIFIER_SHIFT);
+  WidgetUtils::GetLatinCharCodeForKeyCode(
+      mDOMKeyCode, capsLockState.GetModifiers(), &mUnshiftedLatinChar,
+      &mShiftedLatinChar);
+
+  // If the mShiftedLatinChar isn't 0, the key code is NS_VK_[A-Z].
+  if (mShiftedLatinChar) {
+    // If the produced characters of the key on current keyboard layout
+    // are same as computed Latin characters, we shouldn't append the
+    // Latin characters to alternativeCharCode.
+    if (mUnshiftedLatinChar == mUnshiftedString.CharAt(0) &&
+        mShiftedLatinChar == mShiftedString.CharAt(0)) {
+      mShiftedLatinChar = mUnshiftedLatinChar = 0;
+    }
+  } else if (mUnshiftedLatinChar) {
+    // If the mShiftedLatinChar is 0, the mKeyCode doesn't produce
+    // alphabet character.  At that time, the character may be produced
+    // with Shift key.  E.g., on French keyboard layout, NS_VK_PERCENT
+    // key produces LATIN SMALL LETTER U WITH GRAVE (U+00F9) without
+    // Shift key but with Shift key, it produces '%'.
+    // If the mUnshiftedLatinChar is produced by the key on current
+    // keyboard layout, we shouldn't append it to alternativeCharCode.
+    if (mUnshiftedLatinChar == mUnshiftedString.CharAt(0) ||
+        mUnshiftedLatinChar == mShiftedString.CharAt(0)) {
+      mUnshiftedLatinChar = 0;
+    }
+  }
+
+  if (!mModKeyState.IsControl()) {
+    return;
+  }
+
+  // If the mCharCode is not ASCII character, we should replace the
+  // mCharCode with ASCII character only when Ctrl is pressed.
+  // But don't replace the mCharCode when the mCharCode is not same as
+  // unmodified characters. In such case, Ctrl is sometimes used for a
+  // part of character inputting key combination like Shift.
+  uint32_t ch =
+      mModKeyState.IsShift() ? mShiftedLatinChar : mUnshiftedLatinChar;
+  if (!ch) {
+    return;
+  }
+  if (mInputtingStringAndModifiers.IsEmpty() ||
+      mInputtingStringAndModifiers.UniCharsCaseInsensitiveEqual(
+          mModKeyState.IsShift() ? mShiftedString : mUnshiftedString)) {
+    mInputtingStringAndModifiers.Clear();
+    mInputtingStringAndModifiers.Append(ch, mModKeyState.GetModifiers());
+  }
+}
+
+bool NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages() const {
+  MOZ_ASSERT(IsKeyDownMessage());
+  MOZ_ASSERT(IsFollowedByPrintableCharOrSysCharMessage());
+  MOZ_ASSERT(!mWidget->Destroyed());
+
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Error,
+        ("%p   NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages(), "
+         "FAILED due to BeginNativeInputTransaction() failure",
+         this));
+    return true;
+  }
+  WidgetKeyboardEvent keypressEvent(true, eKeyPress, mWidget);
+  MOZ_LOG(gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages(), "
+           "initializing keypress event...",
+           this));
+  ModifierKeyState modKeyState(mModKeyState);
+  if (mCanIgnoreModifierStateAtKeyPress && IsFollowedByPrintableCharMessage()) {
+    // If eKeyPress event should cause inputting text in focused editor,
+    // we need to remove Alt and Ctrl state.
+    modKeyState.Unset(MODIFIER_ALT | MODIFIER_CONTROL);
+  }
+  // We don't need to send char message here if there are two or more retrieved
+  // messages because we need to set each message to each eKeyPress event.
+  bool needsCallback = mFollowingCharMsgs.Length() > 1;
+  nsEventStatus status = InitKeyEvent(keypressEvent, modKeyState);
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages(), "
+           "dispatching keypress event(s)...",
+           this));
+  bool dispatched = mDispatcher->MaybeDispatchKeypressEvents(
+      keypressEvent, status, const_cast<NativeKey*>(this), needsCallback);
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages(), "
+         "keypress event(s) caused destroying the widget",
+         this));
+    return true;
+  }
+  bool consumed = status == nsEventStatus_eConsumeNoDefault;
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::DispatchKeyPressEventsWithRetrievedCharMessages(), "
+           "dispatched keypress event(s), dispatched=%s, consumed=%s",
+           this, GetBoolName(dispatched), GetBoolName(consumed)));
+  return consumed;
+}
+
+bool NativeKey::DispatchKeyPressEventsWithoutCharMessage() const {
+  MOZ_ASSERT(IsKeyDownMessage());
+  MOZ_ASSERT(!mIsDeadKey || !mCommittedCharsAndModifiers.IsEmpty());
+  MOZ_ASSERT(!mWidget->Destroyed());
+
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gKeyLog, LogLevel::Error,
+            ("%p   NativeKey::DispatchKeyPressEventsWithoutCharMessage(), "
+             "FAILED due "
+             "to BeginNativeInputTransaction() failure",
+             this));
+    return true;
+  }
+
+  WidgetKeyboardEvent keypressEvent(true, eKeyPress, mWidget);
+  if (mInputtingStringAndModifiers.IsEmpty() && mShiftedString.IsEmpty() &&
+      mUnshiftedString.IsEmpty()) {
+    keypressEvent.mKeyCode = mDOMKeyCode;
+  }
+  MOZ_LOG(gKeyLog, LogLevel::Debug,
+          ("%p   NativeKey::DispatchKeyPressEventsWithoutCharMessage(), "
+           "initializing "
+           "keypress event...",
+           this));
+  nsEventStatus status = InitKeyEvent(keypressEvent, mModKeyState);
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("%p   NativeKey::DispatchKeyPressEventsWithoutCharMessage(), "
+           "dispatching "
+           "keypress event(s)...",
+           this));
+  bool dispatched = mDispatcher->MaybeDispatchKeypressEvents(
+      keypressEvent, status, const_cast<NativeKey*>(this));
+  if (mWidget->Destroyed()) {
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::DispatchKeyPressEventsWithoutCharMessage(), "
+             "keypress event(s) caused destroying the widget",
+             this));
+    return true;
+  }
+  bool consumed = status == nsEventStatus_eConsumeNoDefault;
+  MOZ_LOG(
+      gKeyLog, LogLevel::Info,
+      ("%p   NativeKey::DispatchKeyPressEventsWithoutCharMessage(), dispatched "
+       "keypress event(s), dispatched=%s, consumed=%s",
+       this, GetBoolName(dispatched), GetBoolName(consumed)));
+  return consumed;
+}
+
+void NativeKey::WillDispatchKeyboardEvent(WidgetKeyboardEvent& aKeyboardEvent,
+                                          uint32_t aIndex) {
+  // If it's an eKeyPress event and it's generated from retrieved char message,
+  // we need to set raw message information for plugins.
+  if (aKeyboardEvent.mMessage == eKeyPress &&
+      IsFollowedByPrintableCharOrSysCharMessage()) {
+    MOZ_RELEASE_ASSERT(aIndex < mCommittedCharsAndModifiers.Length());
+    uint32_t foundPrintableCharMessages = 0;
+    for (size_t i = 0; i < mFollowingCharMsgs.Length(); ++i) {
+      if (!IsPrintableCharOrSysCharMessage(mFollowingCharMsgs[i])) {
+        // XXX Should we dispatch a plugin event for WM_*DEADCHAR messages and
+        //     WM_CHAR with a control character here?  But we're not sure
+        //     how can we create such message queue (i.e., WM_CHAR or
+        //     WM_SYSCHAR with a printable character and such message are
+        //     generated by a keydown).  So, let's ignore such case until
+        //     we'd get some bug reports.
+        MOZ_LOG(gKeyLog, LogLevel::Warning,
+                ("%p   NativeKey::WillDispatchKeyboardEvent(), WARNING, "
+                 "ignoring %zuth message due to non-printable char message, %s",
+                 this, i + 1, ToString(mFollowingCharMsgs[i]).get()));
+        continue;
+      }
+      if (foundPrintableCharMessages++ == aIndex) {
+        // Found message which caused the eKeyPress event.
+        break;
+      }
+    }
+    // Set modifier state from mCommittedCharsAndModifiers because some of them
+    // might be different.  For example, Shift key was pressed at inputting
+    // dead char but Shift key was released before inputting next character.
+    if (mCanIgnoreModifierStateAtKeyPress) {
+      ModifierKeyState modKeyState(mModKeyState);
+      modKeyState.Unset(MODIFIER_SHIFT | MODIFIER_CONTROL | MODIFIER_ALT |
+                        MODIFIER_ALTGRAPH | MODIFIER_CAPSLOCK);
+      modKeyState.Set(mCommittedCharsAndModifiers.ModifiersAt(aIndex));
+      modKeyState.InitInputEvent(aKeyboardEvent);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::WillDispatchKeyboardEvent(), "
+               "setting %uth modifier state to %s",
+               this, aIndex + 1, ToString(modKeyState).get()));
+    }
+  }
+  size_t longestLength =
+      std::max(mInputtingStringAndModifiers.Length(),
+               std::max(mShiftedString.Length(), mUnshiftedString.Length()));
+  size_t skipUniChars = longestLength - mInputtingStringAndModifiers.Length();
+  size_t skipShiftedChars = longestLength - mShiftedString.Length();
+  size_t skipUnshiftedChars = longestLength - mUnshiftedString.Length();
+  if (aIndex >= longestLength) {
+    MOZ_LOG(
+        gKeyLog, LogLevel::Info,
+        ("%p   NativeKey::WillDispatchKeyboardEvent(), does nothing for %uth "
+         "%s event",
+         this, aIndex + 1, ToChar(aKeyboardEvent.mMessage)));
+    return;
+  }
+
+  // Check if aKeyboardEvent is the last event for a key press.
+  // So, if it's not an eKeyPress event, it's always the last event.
+  // Otherwise, check if the index is the last character of
+  // mCommittedCharsAndModifiers.
+  bool isLastIndex = aKeyboardEvent.mMessage != eKeyPress ||
+                     mCommittedCharsAndModifiers.IsEmpty() ||
+                     mCommittedCharsAndModifiers.Length() - 1 == aIndex;
+
+  nsTArray<AlternativeCharCode>& altArray =
+      aKeyboardEvent.mAlternativeCharCodes;
+
+  // Set charCode and adjust modifier state for every eKeyPress event.
+  // This is not necessary for the other keyboard events because the other
+  // keyboard events shouldn't have non-zero charCode value and should have
+  // current modifier state.
+  if (aKeyboardEvent.mMessage == eKeyPress && skipUniChars <= aIndex) {
+    // XXX Modifying modifier state of aKeyboardEvent is illegal, but no way
+    //     to set different modifier state per keypress event except this
+    //     hack.  Note that ideally, dead key should cause composition events
+    //     instead of keypress events, though.
+    if (aIndex - skipUniChars < mInputtingStringAndModifiers.Length()) {
+      ModifierKeyState modKeyState(mModKeyState);
+      // If key in combination with Alt and/or Ctrl produces a different
+      // character than without them then do not report these flags
+      // because it is separate keyboard layout shift state. If dead-key
+      // and base character does not produce a valid composite character
+      // then both produced dead-key character and following base
+      // character may have different modifier flags, too.
+      modKeyState.Unset(MODIFIER_SHIFT | MODIFIER_CONTROL | MODIFIER_ALT |
+                        MODIFIER_ALTGRAPH | MODIFIER_CAPSLOCK);
+      modKeyState.Set(
+          mInputtingStringAndModifiers.ModifiersAt(aIndex - skipUniChars));
+      modKeyState.InitInputEvent(aKeyboardEvent);
+      MOZ_LOG(gKeyLog, LogLevel::Info,
+              ("%p   NativeKey::WillDispatchKeyboardEvent(), "
+               "setting %uth modifier state to %s",
+               this, aIndex + 1, ToString(modKeyState).get()));
+    }
+    uint16_t uniChar =
+        mInputtingStringAndModifiers.CharAt(aIndex - skipUniChars);
+
+    // The mCharCode was set from mKeyValue. However, for example, when Ctrl key
+    // is pressed, its value should indicate an ASCII character for backward
+    // compatibility rather than inputting character without the modifiers.
+    // Therefore, we need to modify mCharCode value here.
+    aKeyboardEvent.SetCharCode(uniChar);
+    MOZ_LOG(gKeyLog, LogLevel::Info,
+            ("%p   NativeKey::WillDispatchKeyboardEvent(), "
+             "setting %uth charCode to %s",
+             this, aIndex + 1, GetCharacterCodeName(uniChar).get()));
+  }
+
+  // We need to append alterntaive charCode values:
+  //   - if the event is eKeyPress, we need to append for the index because
+  //     eKeyPress event is dispatched for every character inputted by a
+  //     key press.
+  //   - if the event is not eKeyPress, we need to append for all characters
+  //     inputted by the key press because the other keyboard events (e.g.,
+  //     eKeyDown are eKeyUp) are fired only once for a key press.
+  size_t count;
+  if (aKeyboardEvent.mMessage == eKeyPress) {
+    // Basically, append alternative charCode values only for the index.
+    count = 1;
+    // However, if it's the last eKeyPress event but different shift state
+    // can input longer string, the last eKeyPress event should have all
+    // remaining alternative charCode values.
+    if (isLastIndex) {
+      count = longestLength - aIndex;
+    }
+  } else {
+    count = longestLength;
+  }
+  for (size_t i = 0; i < count; ++i) {
+    uint16_t shiftedChar = 0, unshiftedChar = 0;
+    if (skipShiftedChars <= aIndex + i) {
+      shiftedChar = mShiftedString.CharAt(aIndex + i - skipShiftedChars);
+    }
+    if (skipUnshiftedChars <= aIndex + i) {
+      unshiftedChar = mUnshiftedString.CharAt(aIndex + i - skipUnshiftedChars);
+    }
+
+    if (shiftedChar || unshiftedChar) {
+      AlternativeCharCode chars(unshiftedChar, shiftedChar);
+      altArray.AppendElement(chars);
+    }
+
+    if (!isLastIndex) {
+      continue;
+    }
+
+    if (mUnshiftedLatinChar || mShiftedLatinChar) {
+      AlternativeCharCode chars(mUnshiftedLatinChar, mShiftedLatinChar);
+      altArray.AppendElement(chars);
+    }
+
+    // Typically, following virtual keycodes are used for a key which can
+    // input the character.  However, these keycodes are also used for
+    // other keys on some keyboard layout.  E.g., in spite of Shift+'1'
+    // inputs '+' on Thai keyboard layout, a key which is at '=/+'
+    // key on ANSI keyboard layout is VK_OEM_PLUS.  Native applications
+    // handle it as '+' key if Ctrl key is pressed.
+    char16_t charForOEMKeyCode = 0;
+    switch (mVirtualKeyCode) {
+      case VK_OEM_PLUS:
+        charForOEMKeyCode = '+';
+        break;
+      case VK_OEM_COMMA:
+        charForOEMKeyCode = ',';
+        break;
+      case VK_OEM_MINUS:
+        charForOEMKeyCode = '-';
+        break;
+      case VK_OEM_PERIOD:
+        charForOEMKeyCode = '.';
+        break;
+    }
+    if (charForOEMKeyCode && charForOEMKeyCode != mUnshiftedString.CharAt(0) &&
+        charForOEMKeyCode != mShiftedString.CharAt(0) &&
+        charForOEMKeyCode != mUnshiftedLatinChar &&
+        charForOEMKeyCode != mShiftedLatinChar) {
+      AlternativeCharCode OEMChars(charForOEMKeyCode, charForOEMKeyCode);
+      altArray.AppendElement(OEMChars);
+    }
+  }
+}
+
+/*****************************************************************************
+ * mozilla::widget::KeyboardLayout
+ *****************************************************************************/
+
+KeyboardLayout* KeyboardLayout::sInstance = nullptr;
+StaticRefPtr<nsIUserIdleServiceInternal> KeyboardLayout::sIdleService;
+
+// static
+KeyboardLayout* KeyboardLayout::GetInstance() {
+  if (!sInstance) {
+    sInstance = new KeyboardLayout();
+  }
+  return sInstance;
+}
+
+// static
+void KeyboardLayout::Shutdown() {
+  delete sInstance;
+  sInstance = nullptr;
+  sIdleService = nullptr;
+}
+
+// static
+void KeyboardLayout::NotifyIdleServiceOfUserActivity() {
+  if (!sIdleService) {
+    sIdleService = nsCOMPtr<nsIUserIdleServiceInternal>(
+                       do_GetService("@mozilla.org/widget/useridleservice;1"))
+                       .forget();
+    if (NS_WARN_IF(!sIdleService)) {
+      return;
+    }
+  }
+  sIdleService->ResetIdleTimeOut(0);
+}
+
+KeyboardLayout::KeyboardLayout() {
+  mDeadKeyTableListHead = nullptr;
+  // A dead key sequence should be made from up to 5 keys.  Therefore, 4 is
+  // enough and makes sense because the item is uint8_t.
+  // (Although, even if it's possible to be 6 keys or more in a sequence,
+  // this array will be re-allocated).
+  mActiveDeadKeys.SetCapacity(4);
+  mDeadKeyShiftStates.SetCapacity(4);
+
+  // If we put it off to load active keyboard layout when first needed, we need
+  // to load it at instanciation.  That makes us save the cost of a call of
+  // GetKeyboardLayout() API.
+  if (StaticPrefs::ui_key_layout_load_when_first_needed()) {
+    OnLayoutChange(::GetKeyboardLayout(0));
+  }
+}
+
+KeyboardLayout::~KeyboardLayout() { ReleaseDeadKeyTables(); }
+
+bool KeyboardLayout::IsPrintableCharKey(uint8_t aVirtualKey) {
+  return GetKeyIndex(aVirtualKey) >= 0;
+}
+
+WORD KeyboardLayout::ComputeScanCodeForVirtualKeyCode(
+    uint8_t aVirtualKeyCode) const {
+  return static_cast<WORD>(::MapVirtualKeyEx(aVirtualKeyCode, MAPVK_VK_TO_VSC,
+                                             KeyboardLayout::GetLayout()));
+}
+
+bool KeyboardLayout::IsDeadKey(uint8_t aVirtualKey,
+                               const ModifierKeyState& aModKeyState) const {
+  int32_t virtualKeyIndex = GetKeyIndex(aVirtualKey);
+
+  // XXX KeyboardLayout class doesn't support unusual keyboard layout which
+  //     maps some function keys as dead keys.
+  if (virtualKeyIndex < 0) {
+    return false;
+  }
+
+  return mVirtualKeys[virtualKeyIndex].IsDeadKey(
+      VirtualKey::ModifiersToShiftState(aModKeyState.GetModifiers()));
+}
+
+bool KeyboardLayout::IsSysKey(uint8_t aVirtualKey,
+                              const ModifierKeyState& aModKeyState) const {
+  // If Alt key is not pressed, it's never a system key combination.
+  // Additionally, if Ctrl key is pressed, it's never a system key combination
+  // too.
+  // FYI: Windows logo key state won't affect if it's a system key.
+  if (!aModKeyState.IsAlt() || aModKeyState.IsControl()) {
+    return false;
+  }
+
+  int32_t virtualKeyIndex = GetKeyIndex(aVirtualKey);
+  if (virtualKeyIndex < 0) {
+    return true;
+  }
+
+  UniCharsAndModifiers inputCharsAndModifiers =
+      GetUniCharsAndModifiers(aVirtualKey, aModKeyState);
+  if (inputCharsAndModifiers.IsEmpty()) {
+    return true;
+  }
+
+  // If the Alt key state isn't consumed, that means that the key with Alt
+  // doesn't cause text input.  So, the combination is a system key.
+  return !!(inputCharsAndModifiers.ModifiersAt(0) & MODIFIER_ALT);
+}
+
+void KeyboardLayout::InitNativeKey(NativeKey& aNativeKey) {
+  if (mIsPendingToRestoreKeyboardLayout) {
+    LoadLayout(::GetKeyboardLayout(0));
+  }
+
+  // If the aNativeKey is initialized with WM_CHAR, the key information
+  // should be discarded because mKeyValue should have the string to be
+  // inputted.
+  if (aNativeKey.mMsg.message == WM_CHAR) {
+    char16_t ch = static_cast<char16_t>(aNativeKey.mMsg.wParam);
+    // But don't set key value as printable key if the character is a control
+    // character such as 0x0D at pressing Enter key.
+    if (!NativeKey::IsControlChar(ch)) {
+      aNativeKey.mKeyNameIndex = KEY_NAME_INDEX_USE_STRING;
+      Modifiers modifiers =
+          aNativeKey.GetModifiers() & ~(MODIFIER_ALT | MODIFIER_CONTROL);
+      aNativeKey.mCommittedCharsAndModifiers.Append(ch, modifiers);
+      return;
+    }
+  }
+
+  // If the aNativeKey is in a sequence to input a Unicode character with
+  // Alt + numpad keys, we should just set the number as the inputting charcter.
+  // Note that we should compute the key value from the virtual key code
+  // because they may be mapped to alphabets, but they should be treated as
+  // Alt + [0-9] even by web apps.
+  // However, we shouldn't touch the key value if given virtual key code is
+  // not a printable key because it may be synthesized by 3rd party utility
+  // or just NumLock is unlocked and user tries to use shortcut key.  In the
+  // latter case, we cannot solve the conflict issue with Alt+foo shortcut key
+  // and inputting a Unicode scalar value like reported to bug 1606655, though,
+  // I have no better idea.  Perhaps, `Alt` shouldn't be used for shortcut key
+  // combination on Windows.
+  if (aNativeKey.MaybeTypingUnicodeScalarValue() &&
+      KeyboardLayout::IsPrintableCharKey(aNativeKey.mVirtualKeyCode)) {
+    // If the key code value is mapped to a Numpad key, let's compute the key
+    // value with it.  This is same behavior as Chrome.  In strictly speaking,
+    // I think that the else block's computation is better because it seems
+    // that Windows does not refer virtual key code value, but we should avoid
+    // web-compat issues.
+    char16_t num = '0';
+    if (aNativeKey.mVirtualKeyCode >= VK_NUMPAD0 &&
+        aNativeKey.mVirtualKeyCode <= VK_NUMPAD9) {
+      num = '0' + aNativeKey.mVirtualKeyCode - VK_NUMPAD0;
+    }
+    // Otherwise, let's use fake key value for making never match with
+    // mnemonic.
+    else {
+      switch (aNativeKey.mScanCode) {
+        case 0x0052:  // Numpad0
+          num = '0';
+          break;
+        case 0x004F:  // Numpad1
+          num = '1';
+          break;
+        case 0x0050:  // Numpad2
+          num = '2';
+          break;
+        case 0x0051:  // Numpad3
+          num = '3';
+          break;
+        case 0x004B:  // Numpad4
+          num = '4';
+          break;
+        case 0x004C:  // Numpad5
+          num = '5';
+          break;
+        case 0x004D:  // Numpad6
+          num = '6';
+          break;
+        case 0x0047:  // Numpad7
+          num = '7';
+          break;
+        case 0x0048:  // Numpad8
+          num = '8';
+          break;
+        case 0x0049:  // Numpad9
+          num = '9';
+          break;
+        default:
+          MOZ_ASSERT_UNREACHABLE(
+              "IsTypingUnicodeScalarValue() must have returned true for wrong "
+              "scancode");
+          break;
+      }
+    }
+    aNativeKey.mCommittedCharsAndModifiers.Append(num,
+                                                  aNativeKey.GetModifiers());
+    aNativeKey.mKeyNameIndex = KEY_NAME_INDEX_USE_STRING;
+    return;
+  }
+
+  // When it's followed by non-dead char message(s) for printable character(s),
+  // aNativeKey should dispatch eKeyPress events for them rather than
+  // information from keyboard layout because respecting WM_(SYS)CHAR messages
+  // guarantees that we can always input characters which is expected by
+  // the user even if the user uses odd keyboard layout.
+  // Or, when it was followed by non-dead char message for a printable character
+  // but it's gone at removing the message from the queue, let's treat it
+  // as a key inputting empty string.
+  if (aNativeKey.IsFollowedByPrintableCharOrSysCharMessage() ||
+      aNativeKey.mCharMessageHasGone) {
+    MOZ_ASSERT(!aNativeKey.IsCharMessage(aNativeKey.mMsg));
+    if (aNativeKey.IsFollowedByPrintableCharOrSysCharMessage()) {
+      // Initialize mCommittedCharsAndModifiers with following char messages.
+      aNativeKey.InitCommittedCharsAndModifiersWithFollowingCharMessages();
+      MOZ_ASSERT(!aNativeKey.mCommittedCharsAndModifiers.IsEmpty());
+
+      // Currently, we are doing a ugly hack to keypress events to cause
+      // inputting character even if Ctrl or Alt key is pressed, that is, we
+      // remove Ctrl and Alt modifier state from keypress event.  However, for
+      // example, Ctrl+Space which causes ' ' of WM_CHAR message never causes
+      // keypress event whose ctrlKey is true.  For preventing this problem,
+      // we should mark as not removable if Ctrl or Alt key does not cause
+      // changing inputting character.
+      if (IsPrintableCharKey(aNativeKey.mOriginalVirtualKeyCode) &&
+          (aNativeKey.IsControl() ^ aNativeKey.IsAlt())) {
+        ModifierKeyState state = aNativeKey.ModifierKeyStateRef();
+        state.Unset(MODIFIER_ALT | MODIFIER_CONTROL);
+        UniCharsAndModifiers charsWithoutModifier =
+            GetUniCharsAndModifiers(aNativeKey.GenericVirtualKeyCode(), state);
+        aNativeKey.mCanIgnoreModifierStateAtKeyPress =
+            !charsWithoutModifier.UniCharsEqual(
+                aNativeKey.mCommittedCharsAndModifiers);
+      }
+    } else {
+      aNativeKey.mCommittedCharsAndModifiers.Clear();
+    }
+    aNativeKey.mKeyNameIndex = KEY_NAME_INDEX_USE_STRING;
+
+    // If it's not in dead key sequence, we don't need to do anymore here.
+    if (!IsInDeadKeySequence()) {
+      return;
+    }
+
+    // If it's in dead key sequence and dead char is inputted as is, we need to
+    // set the previous modifier state which is stored when preceding dead key
+    // is pressed.
+    UniCharsAndModifiers deadChars = GetDeadUniCharsAndModifiers();
+    aNativeKey.mCommittedCharsAndModifiers.OverwriteModifiersIfBeginsWith(
+        deadChars);
+    // Finish the dead key sequence.
+    DeactivateDeadKeyState();
+    return;
+  }
+
+  // If it's a dead key, aNativeKey will be initialized by
+  // MaybeInitNativeKeyAsDeadKey().
+  if (MaybeInitNativeKeyAsDeadKey(aNativeKey)) {
+    return;
+  }
+
+  // If the key is not a usual printable key, KeyboardLayout class assume that
+  // it's not cause dead char nor printable char.  Therefore, there are nothing
+  // to do here fore such keys (e.g., function keys).
+  // However, this should keep dead key state even if non-printable key is
+  // pressed during a dead key sequence.
+  if (!IsPrintableCharKey(aNativeKey.mOriginalVirtualKeyCode)) {
+    return;
+  }
+
+  MOZ_ASSERT(aNativeKey.mOriginalVirtualKeyCode != VK_PACKET,
+             "At handling VK_PACKET, we shouldn't refer keyboard layout");
+  MOZ_ASSERT(
+      aNativeKey.mKeyNameIndex == KEY_NAME_INDEX_USE_STRING,
+      "Printable key's key name index must be KEY_NAME_INDEX_USE_STRING");
+
+  // If it's in dead key handling and the pressed key causes a composite
+  // character, aNativeKey will be initialized by
+  // MaybeInitNativeKeyWithCompositeChar().
+  if (MaybeInitNativeKeyWithCompositeChar(aNativeKey)) {
+    return;
+  }
+
+  UniCharsAndModifiers baseChars = GetUniCharsAndModifiers(aNativeKey);
+
+  // If the key press isn't related to any dead keys, initialize aNativeKey
+  // with the characters which should be caused by the key.
+  if (!IsInDeadKeySequence()) {
+    aNativeKey.mCommittedCharsAndModifiers = baseChars;
+    return;
+  }
+
+  // If the key doesn't cause a composite character with preceding dead key,
+  // initialize aNativeKey with the dead-key character followed by current
+  // key's character.
+  UniCharsAndModifiers deadChars = GetDeadUniCharsAndModifiers();
+  aNativeKey.mCommittedCharsAndModifiers = deadChars + baseChars;
+  if (aNativeKey.IsKeyDownMessage()) {
+    DeactivateDeadKeyState();
+  }
+}
+
+bool KeyboardLayout::MaybeInitNativeKeyAsDeadKey(NativeKey& aNativeKey) {
+  // Only when it's not in dead key sequence, we can trust IsDeadKey() result.
+  if (!IsInDeadKeySequence() && !IsDeadKey(aNativeKey)) {
+    return false;
+  }
+
+  // When keydown message is followed by a dead char message, it should be
+  // initialized as dead key.
+  bool isDeadKeyDownEvent =
+      aNativeKey.IsKeyDownMessage() && aNativeKey.IsFollowedByDeadCharMessage();
+
+  // When keyup message is received, let's check if it's one of preceding
+  // dead keys because keydown message order and keyup message order may be
+  // different.
+  bool isDeadKeyUpEvent =
+      !aNativeKey.IsKeyDownMessage() &&
+      mActiveDeadKeys.Contains(aNativeKey.GenericVirtualKeyCode());
+
+  if (isDeadKeyDownEvent || isDeadKeyUpEvent) {
+    ActivateDeadKeyState(aNativeKey);
+    // Any dead key events don't generate characters.  So, a dead key should
+    // cause only keydown event and keyup event whose KeyboardEvent.key
+    // values are "Dead".
+    aNativeKey.mCommittedCharsAndModifiers.Clear();
+    aNativeKey.mKeyNameIndex = KEY_NAME_INDEX_Dead;
+    return true;
+  }
+
+  // At keydown message handling, we need to forget the first dead key
+  // because there is no guarantee coming WM_KEYUP for the second dead
+  // key before next WM_KEYDOWN.  E.g., due to auto key repeat or pressing
+  // another dead key before releasing current key.  Therefore, we can
+  // set only a character for current key for keyup event.
+  if (!IsInDeadKeySequence()) {
+    aNativeKey.mCommittedCharsAndModifiers =
+        GetUniCharsAndModifiers(aNativeKey);
+    return true;
+  }
+
+  // When non-printable key event comes during a dead key sequence, that must
+  // be a modifier key event.  So, such events shouldn't be handled as a part
+  // of the dead key sequence.
+  if (!IsDeadKey(aNativeKey)) {
+    return false;
+  }
+
+  // FYI: Following code may run when the user doesn't input text actually
+  //      but the key sequence is a dead key sequence.  For example,
+  //      ` -> Ctrl+` with Spanish keyboard layout.  Let's keep using this
+  //      complicated code for now because this runs really rarely.
+
+  // Dead key followed by another dead key may cause a composed character
+  // (e.g., "Russian - Mnemonic" keyboard layout's 's' -> 'c').
+  if (MaybeInitNativeKeyWithCompositeChar(aNativeKey)) {
+    return true;
+  }
+
+  // Otherwise, dead key followed by another dead key causes inputting both
+  // character.
+  UniCharsAndModifiers prevDeadChars = GetDeadUniCharsAndModifiers();
+  UniCharsAndModifiers newChars = GetUniCharsAndModifiers(aNativeKey);
+  // But keypress events should be fired for each committed character.
+  aNativeKey.mCommittedCharsAndModifiers = prevDeadChars + newChars;
+  if (aNativeKey.IsKeyDownMessage()) {
+    DeactivateDeadKeyState();
+  }
+  return true;
+}
+
+bool KeyboardLayout::MaybeInitNativeKeyWithCompositeChar(
+    NativeKey& aNativeKey) {
+  if (!IsInDeadKeySequence()) {
+    return false;
+  }
+
+  if (NS_WARN_IF(!IsPrintableCharKey(aNativeKey.mOriginalVirtualKeyCode))) {
+    return false;
+  }
+
+  UniCharsAndModifiers baseChars = GetUniCharsAndModifiers(aNativeKey);
+  if (baseChars.IsEmpty() || !baseChars.CharAt(0)) {
+    return false;
+  }
+
+  char16_t compositeChar = GetCompositeChar(baseChars.CharAt(0));
+  if (!compositeChar) {
+    return false;
+  }
+
+  // Active dead-key and base character does produce exactly one composite
+  // character.
+  aNativeKey.mCommittedCharsAndModifiers.Append(compositeChar,
+                                                baseChars.ModifiersAt(0));
+  if (aNativeKey.IsKeyDownMessage()) {
+    DeactivateDeadKeyState();
+  }
+  return true;
+}
+
+UniCharsAndModifiers KeyboardLayout::GetUniCharsAndModifiers(
+    uint8_t aVirtualKey, VirtualKey::ShiftState aShiftState) const {
+  UniCharsAndModifiers result;
+  int32_t key = GetKeyIndex(aVirtualKey);
+  if (key < 0) {
+    return result;
+  }
+  return mVirtualKeys[key].GetUniChars(aShiftState);
+}
+
+UniCharsAndModifiers KeyboardLayout::GetDeadUniCharsAndModifiers() const {
+  MOZ_RELEASE_ASSERT(mActiveDeadKeys.Length() == mDeadKeyShiftStates.Length());
+
+  if (NS_WARN_IF(mActiveDeadKeys.IsEmpty())) {
+    return UniCharsAndModifiers();
+  }
+
+  UniCharsAndModifiers result;
+  for (size_t i = 0; i < mActiveDeadKeys.Length(); ++i) {
+    result +=
+        GetUniCharsAndModifiers(mActiveDeadKeys[i], mDeadKeyShiftStates[i]);
+  }
+  return result;
+}
+
+char16_t KeyboardLayout::GetCompositeChar(char16_t aBaseChar) const {
+  if (NS_WARN_IF(mActiveDeadKeys.IsEmpty())) {
+    return 0;
+  }
+  // XXX Currently, we don't support computing a composite character with
+  //     two or more dead keys since it needs big table for supporting
+  //     long chained dead keys.  However, this should be a minor bug
+  //     because this runs only when the latest keydown event does not cause
+  //     WM_(SYS)CHAR messages.  So, when user wants to input a character,
+  //     this path never runs.
+  if (mActiveDeadKeys.Length() > 1) {
+    return 0;
+  }
+  int32_t key = GetKeyIndex(mActiveDeadKeys[0]);
+  if (key < 0) {
+    return 0;
+  }
+  return mVirtualKeys[key].GetCompositeChar(mDeadKeyShiftStates[0], aBaseChar);
+}
+
+static bool IsValidKeyboardLayoutsChild(const nsAString& aChildName) {
+  if (aChildName.Length() != 8) {
+    return false;
+  }
+  for (size_t i = 0; i < aChildName.Length(); i++) {
+    if ((aChildName[i] >= '0' && aChildName[i] <= '9') ||
+        (aChildName[i] >= 'a' && aChildName[i] <= 'f') ||
+        (aChildName[i] >= 'A' && aChildName[i] <= 'F')) {
+      continue;
+    }
+    return false;
+  }
+  return true;
+}
+
+// static
+nsCString KeyboardLayout::GetLayoutName(HKL aLayout) {
+  constexpr auto kKeyboardLayouts =
+      u"SYSTEM\\CurrentControlSet\\Control\\Keyboard Layouts\\"_ns;
+  uint16_t language = reinterpret_cast<uintptr_t>(aLayout) & 0xFFFF;
+  uint16_t layout = (reinterpret_cast<uintptr_t>(aLayout) >> 16) & 0xFFFF;
+  // If the layout is less than 0xA000XXXX (normal keyboard layout for the
+  // language) or 0xEYYYXXXX (IMM-IME), we can retrieve its name simply.
+  if (layout < 0xA000 || (layout & 0xF000) == 0xE000) {
+    nsAutoString key(kKeyboardLayouts);
+    key.AppendPrintf("%08" PRIXPTR, layout < 0xA000
+                                        ? layout
+                                        : reinterpret_cast<uintptr_t>(aLayout));
+    wchar_t buf[256];
+    if (NS_WARN_IF(!WinRegistry::GetString(
+            HKEY_LOCAL_MACHINE, key, u"Layout Text"_ns, buf,
+            WinRegistry::kLegacyWinUtilsStringFlags))) {
+      return "No name or too long name"_ns;
+    }
+    return NS_ConvertUTF16toUTF8(buf);
+  }
+
+  if (NS_WARN_IF((layout & 0xF000) != 0xF000)) {
+    nsCString result;
+    result.AppendPrintf("Odd HKL: 0x%08" PRIXPTR,
+                        reinterpret_cast<uintptr_t>(aLayout));
+    return result;
+  }
+
+  // Otherwise, we need to walk the registry under "Keyboard Layouts".
+  WinRegistry::Key regKey(HKEY_LOCAL_MACHINE, kKeyboardLayouts,
+                          WinRegistry::KeyMode::Read);
+  if (NS_WARN_IF(!regKey)) {
+    return ""_ns;
+  }
+  uint32_t childCount = regKey.GetChildCount();
+  if (NS_WARN_IF(!childCount)) {
+    return ""_ns;
+  }
+  for (uint32_t i = 0; i < childCount; i++) {
+    nsAutoString childName;
+    if (NS_WARN_IF(!regKey.GetChildName(i, childName)) ||
+        !IsValidKeyboardLayoutsChild(childName)) {
+      continue;
+    }
+    nsresult rv = NS_OK;
+    uint32_t childNum = static_cast<uint32_t>(childName.ToInteger64(&rv, 16));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      continue;
+    }
+    // Ignore normal keyboard layouts for each language.
+    if (childNum <= 0xFFFF) {
+      continue;
+    }
+    // If it doesn't start with 'A' nor 'a', language should be matched.
+    if ((childNum & 0xFFFF) != language &&
+        (childNum & 0xF0000000) != 0xA0000000) {
+      continue;
+    }
+    // Then, the child should have "Layout Id" which is "YYY" of 0xFYYYXXXX.
+    nsAutoString key(kKeyboardLayouts);
+    key += childName;
+    WinRegistry::Key regKey(HKEY_LOCAL_MACHINE, key,
+                            WinRegistry::KeyMode::QueryValue);
+    if (NS_WARN_IF(!regKey)) {
+      continue;
+    }
+    wchar_t buf[256];
+    if (NS_WARN_IF(!regKey.GetValueAsString(
+            u"Layout Id"_ns, buf, WinRegistry::kLegacyWinUtilsStringFlags))) {
+      continue;
+    }
+    uint16_t layoutId = wcstol(buf, nullptr, 16);
+    if (layoutId != (layout & 0x0FFF)) {
+      continue;
+    }
+    if (NS_WARN_IF(!regKey.GetValueAsString(
+            u"Layout Text"_ns, buf, WinRegistry::kLegacyWinUtilsStringFlags))) {
+      continue;
+    }
+    return NS_ConvertUTF16toUTF8(buf);
+  }
+  return ""_ns;
+}
+
+void KeyboardLayout::LoadLayout(HKL aLayout) {
+  mIsPendingToRestoreKeyboardLayout = false;
+
+  if (mKeyboardLayout == aLayout) {
+    return;
+  }
+
+  mKeyboardLayout = aLayout;
+  mHasAltGr = false;
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("KeyboardLayout::LoadLayout(aLayout=0x%p (%s))", aLayout,
+           GetLayoutName(aLayout).get()));
+
+  BYTE kbdState[256];
+  memset(kbdState, 0, sizeof(kbdState));
+
+  BYTE originalKbdState[256];
+  // Bitfield with all shift states that have at least one dead-key.
+  uint16_t shiftStatesWithDeadKeys = 0;
+  // Bitfield with all shift states that produce any possible dead-key base
+  // characters.
+  uint16_t shiftStatesWithBaseChars = 0;
+
+  mActiveDeadKeys.Clear();
+  mDeadKeyShiftStates.Clear();
+
+  ReleaseDeadKeyTables();
+
+  ::GetKeyboardState(originalKbdState);
+
+  // For each shift state gather all printable characters that are produced
+  // for normal case when no any dead-key is active.
+
+  for (VirtualKey::ShiftState shiftState = 0; shiftState < 16; shiftState++) {
+    VirtualKey::FillKbdState(kbdState, shiftState);
+    bool isAltGr = VirtualKey::IsAltGrIndex(shiftState);
+    for (uint32_t virtualKey = 0; virtualKey < 256; virtualKey++) {
+      int32_t vki = GetKeyIndex(virtualKey);
+      if (vki < 0) {
+        continue;
+      }
+      NS_ASSERTION(uint32_t(vki) < ArrayLength(mVirtualKeys), "invalid index");
+      char16_t uniChars[5];
+      int32_t ret = ::ToUnicodeEx(virtualKey, 0, kbdState, (LPWSTR)uniChars,
+                                  ArrayLength(uniChars), 0, mKeyboardLayout);
+      // dead-key
+      if (ret < 0) {
+        shiftStatesWithDeadKeys |= (1 << shiftState);
+        // Repeat dead-key to deactivate it and get its character
+        // representation.
+        char16_t deadChar[2];
+        ret = ::ToUnicodeEx(virtualKey, 0, kbdState, (LPWSTR)deadChar,
+                            ArrayLength(deadChar), 0, mKeyboardLayout);
+        NS_ASSERTION(ret == 2, "Expecting twice repeated dead-key character");
+        mVirtualKeys[vki].SetDeadChar(shiftState, deadChar[0]);
+
+        MOZ_LOG(gKeyLog, LogLevel::Verbose,
+                ("  %s (%d): DeadChar(%s, %s) (ret=%d)",
+                 kVirtualKeyName[virtualKey], vki,
+                 GetShiftStateName(shiftState).get(),
+                 GetCharacterCodeNames(deadChar, 1).get(), ret));
+      } else {
+        if (ret == 1) {
+          // dead-key can pair only with exactly one base character.
+          shiftStatesWithBaseChars |= (1 << shiftState);
+        }
+        mVirtualKeys[vki].SetNormalChars(shiftState, uniChars, ret);
+        MOZ_LOG(gKeyLog, LogLevel::Verbose,
+                ("  %s (%d): NormalChar(%s, %s) (ret=%d)",
+                 kVirtualKeyName[virtualKey], vki,
+                 GetShiftStateName(shiftState).get(),
+                 GetCharacterCodeNames(uniChars, ret).get(), ret));
+      }
+
+      // If the key inputs at least one character with AltGr modifier,
+      // check if AltGr changes inputting character.  If it does, mark
+      // this keyboard layout has AltGr modifier actually.
+      if (!mHasAltGr && ret > 0 && isAltGr &&
+          mVirtualKeys[vki].IsChangedByAltGr(shiftState)) {
+        mHasAltGr = true;
+        MOZ_LOG(gKeyLog, LogLevel::Info,
+                ("  Found a key (%s) changed by AltGr: %s -> %s (%s) (ret=%d)",
+                 kVirtualKeyName[virtualKey],
+                 GetCharacterCodeNames(
+                     mVirtualKeys[vki].GetNativeUniChars(
+                         shiftState - VirtualKey::ShiftStateIndex::eAltGr))
+                     .get(),
+                 GetCharacterCodeNames(
+                     mVirtualKeys[vki].GetNativeUniChars(shiftState))
+                     .get(),
+                 GetShiftStateName(shiftState).get(), ret));
+      }
+    }
+  }
+
+  // Now process each dead-key to find all its base characters and resulting
+  // composite characters.
+  for (VirtualKey::ShiftState shiftState = 0; shiftState < 16; shiftState++) {
+    if (!(shiftStatesWithDeadKeys & (1 << shiftState))) {
+      continue;
+    }
+
+    VirtualKey::FillKbdState(kbdState, shiftState);
+
+    for (uint32_t virtualKey = 0; virtualKey < 256; virtualKey++) {
+      int32_t vki = GetKeyIndex(virtualKey);
+      if (vki >= 0 && mVirtualKeys[vki].IsDeadKey(shiftState)) {
+        AutoTArray<DeadKeyEntry, 256> deadKeyArray;
+        uint32_t n = GetDeadKeyCombinations(
+            virtualKey, kbdState, shiftStatesWithBaseChars, deadKeyArray);
+        const DeadKeyTable* dkt =
+            mVirtualKeys[vki].MatchingDeadKeyTable(deadKeyArray.Elements(), n);
+        if (!dkt) {
+          dkt = AddDeadKeyTable(deadKeyArray.Elements(), n);
+        }
+        mVirtualKeys[vki].AttachDeadKeyTable(shiftState, dkt);
+      }
+    }
+  }
+
+  ::SetKeyboardState(originalKbdState);
+
+  if (MOZ_LOG_TEST(gKeyLog, LogLevel::Verbose)) {
+    static const UINT kExtendedScanCode[] = {0x0000, 0xE000};
+    static const UINT kMapType = MAPVK_VSC_TO_VK_EX;
+    MOZ_LOG(gKeyLog, LogLevel::Verbose,
+            ("Logging virtual keycode values for scancode (0x%p)...",
+             mKeyboardLayout));
+    for (uint32_t i = 0; i < ArrayLength(kExtendedScanCode); i++) {
+      for (uint32_t j = 1; j <= 0xFF; j++) {
+        UINT scanCode = kExtendedScanCode[i] + j;
+        UINT virtualKeyCode =
+            ::MapVirtualKeyEx(scanCode, kMapType, mKeyboardLayout);
+        MOZ_LOG(gKeyLog, LogLevel::Verbose,
+                ("0x%04X, %s", scanCode, kVirtualKeyName[virtualKeyCode]));
+      }
+    }
+  }
+
+  MOZ_LOG(gKeyLog, LogLevel::Info,
+          ("  AltGr key is %s in %s", mHasAltGr ? "found" : "not found",
+           GetLayoutName(aLayout).get()));
+}
+
+inline int32_t KeyboardLayout::GetKeyIndex(uint8_t aVirtualKey) {
+  // Currently these 68 (NS_NUM_OF_KEYS) virtual keys are assumed
+  // to produce visible representation:
+  // 0x20 - VK_SPACE          ' '
+  // 0x30..0x39               '0'..'9'
+  // 0x41..0x5A               'A'..'Z'
+  // 0x60..0x69               '0'..'9' on numpad
+  // 0x6A - VK_MULTIPLY       '*' on numpad
+  // 0x6B - VK_ADD            '+' on numpad
+  // 0x6D - VK_SUBTRACT       '-' on numpad
+  // 0x6E - VK_DECIMAL        '.' on numpad
+  // 0x6F - VK_DIVIDE         '/' on numpad
+  // 0x6E - VK_DECIMAL        '.'
+  // 0xBA - VK_OEM_1          ';:' for US
+  // 0xBB - VK_OEM_PLUS       '+' any country
+  // 0xBC - VK_OEM_COMMA      ',' any country
+  // 0xBD - VK_OEM_MINUS      '-' any country
+  // 0xBE - VK_OEM_PERIOD     '.' any country
+  // 0xBF - VK_OEM_2          '/?' for US
+  // 0xC0 - VK_OEM_3          '`~' for US
+  // 0xC1 - VK_ABNT_C1        '/?' for Brazilian
+  // 0xC2 - VK_ABNT_C2        separator key on numpad (Brazilian or JIS for Mac)
+  // 0xDB - VK_OEM_4          '[{' for US
+  // 0xDC - VK_OEM_5          '\|' for US
+  // 0xDD - VK_OEM_6          ']}' for US
+  // 0xDE - VK_OEM_7          ''"' for US
+  // 0xDF - VK_OEM_8
+  // 0xE1 - no name
+  // 0xE2 - VK_OEM_102        '\_' for JIS
+  // 0xE3 - no name
+  // 0xE4 - no name
+
+  static const int8_t xlat[256] = {
+      // 0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F
+      //-----------------------------------------------------------------------
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 00
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 10
+      0,  -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 20
+      1,  2,  3,  4,  5,  6,  7,  8,  9,  10, -1, -1, -1, -1, -1, -1,  // 30
+      -1, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,  // 40
+      26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, -1, -1, -1, -1, -1,  // 50
+      37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, -1, 49, 50, 51,  // 60
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 70
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 80
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // 90
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // A0
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 52, 53, 54, 55, 56, 57,  // B0
+      58, 59, 60, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // C0
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 61, 62, 63, 64, 65,  // D0
+      -1, 66, 67, 68, 69, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  // E0
+      -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1   // F0
+  };
+
+  return xlat[aVirtualKey];
+}
+
+const DeadKeyTable* KeyboardLayout::AddDeadKeyTable(
+    const DeadKeyEntry* aDeadKeyArray, uint32_t aEntries) {
+  DeadKeyTableListEntry* next = mDeadKeyTableListHead;
+
+  const size_t bytes = offsetof(DeadKeyTableListEntry, data) +
+                       DeadKeyTable::SizeInBytes(aEntries);
+  uint8_t* p = new uint8_t[bytes];
+
+  mDeadKeyTableListHead = reinterpret_cast<DeadKeyTableListEntry*>(p);
+  mDeadKeyTableListHead->next = next;
+
+  DeadKeyTable* dkt =
+      reinterpret_cast<DeadKeyTable*>(mDeadKeyTableListHead->data);
+
+  dkt->Init(aDeadKeyArray, aEntries);
+
+  return dkt;
+}
+
+void KeyboardLayout::ReleaseDeadKeyTables() {
+  while (mDeadKeyTableListHead) {
+    uint8_t* p = reinterpret_cast<uint8_t*>(mDeadKeyTableListHead);
+    mDeadKeyTableListHead = mDeadKeyTableListHead->next;
+
+    delete[] p;
+  }
+}
+
+bool KeyboardLayout::EnsureDeadKeyActive(bool aIsActive, uint8_t aDeadKey,
+                                         const PBYTE aDeadKeyKbdState) {
+  int32_t ret;
+  do {
+    char16_t dummyChars[5];
+    ret =
+        ::ToUnicodeEx(aDeadKey, 0, (PBYTE)aDeadKeyKbdState, (LPWSTR)dummyChars,
+                      ArrayLength(dummyChars), 0, mKeyboardLayout);
+    // returned values:
+    // <0 - Dead key state is active. The keyboard driver will wait for next
+    //      character.
+    //  1 - Previous pressed key was a valid base character that produced
+    //      exactly one composite character.
+    // >1 - Previous pressed key does not produce any composite characters.
+    //      Return dead-key character followed by base character(s).
+  } while ((ret < 0) != aIsActive);
+
+  return (ret < 0);
+}
+
+void KeyboardLayout::ActivateDeadKeyState(const NativeKey& aNativeKey) {
+  // Dead-key state should be activated at keydown.
+  if (!aNativeKey.IsKeyDownMessage()) {
+    return;
+  }
+
+  mActiveDeadKeys.AppendElement(aNativeKey.mOriginalVirtualKeyCode);
+  mDeadKeyShiftStates.AppendElement(aNativeKey.GetShiftState());
+}
+
+void KeyboardLayout::DeactivateDeadKeyState() {
+  if (mActiveDeadKeys.IsEmpty()) {
+    return;
+  }
+
+  BYTE kbdState[256];
+  memset(kbdState, 0, sizeof(kbdState));
+
+  // Assume that the last dead key can finish dead key sequence.
+  VirtualKey::FillKbdState(kbdState, mDeadKeyShiftStates.LastElement());
+  EnsureDeadKeyActive(false, mActiveDeadKeys.LastElement(), kbdState);
+  mActiveDeadKeys.Clear();
+  mDeadKeyShiftStates.Clear();
+}
+
+bool KeyboardLayout::AddDeadKeyEntry(char16_t aBaseChar,
+                                     char16_t aCompositeChar,
+                                     nsTArray<DeadKeyEntry>& aDeadKeyArray) {
+  auto dke = DeadKeyEntry(aBaseChar, aCompositeChar);
+  for (uint32_t index = 0; index < aDeadKeyArray.Length(); index++) {
+    if (aDeadKeyArray[index] == dke) {
+      return false;
+    }
+  }
+
+  aDeadKeyArray.AppendElement(dke);
+
+  return true;
+}
+
+uint32_t KeyboardLayout::GetDeadKeyCombinations(
+    uint8_t aDeadKey, const PBYTE aDeadKeyKbdState,
+    uint16_t aShiftStatesWithBaseChars, nsTArray<DeadKeyEntry>& aDeadKeyArray) {
+  bool deadKeyActive = false;
+  uint32_t entries = 0;
+  BYTE kbdState[256];
+  memset(kbdState, 0, sizeof(kbdState));
+
+  for (uint32_t shiftState = 0; shiftState < 16; shiftState++) {
+    if (!(aShiftStatesWithBaseChars & (1 << shiftState))) {
+      continue;
+    }
+
+    VirtualKey::FillKbdState(kbdState, shiftState);
+
+    for (uint32_t virtualKey = 0; virtualKey < 256; virtualKey++) {
+      int32_t vki = GetKeyIndex(virtualKey);
+      // Dead-key can pair only with such key that produces exactly one base
+      // character.
+      if (vki >= 0 &&
+          mVirtualKeys[vki].GetNativeUniChars(shiftState).Length() == 1) {
+        // Ensure dead-key is in active state, when it swallows entered
+        // character and waits for the next pressed key.
+        if (!deadKeyActive) {
+          deadKeyActive = EnsureDeadKeyActive(true, aDeadKey, aDeadKeyKbdState);
+        }
+
+        // Depending on the character the followed the dead-key, the keyboard
+        // driver can produce one composite character, or a dead-key character
+        // followed by a second character.
+        char16_t compositeChars[5];
+        int32_t ret =
+            ::ToUnicodeEx(virtualKey, 0, kbdState, (LPWSTR)compositeChars,
+                          ArrayLength(compositeChars), 0, mKeyboardLayout);
+        switch (ret) {
+          case 0:
+            // This key combination does not produce any characters. The
+            // dead-key is still in active state.
+            break;
+          case 1: {
+            char16_t baseChars[5];
+            ret = ::ToUnicodeEx(virtualKey, 0, kbdState, (LPWSTR)baseChars,
+                                ArrayLength(baseChars), 0, mKeyboardLayout);
+            if (entries < aDeadKeyArray.Capacity()) {
+              switch (ret) {
+                case 1:
+                  // Exactly one composite character produced. Now, when
+                  // dead-key is not active, repeat the last character one more
+                  // time to determine the base character.
+                  if (AddDeadKeyEntry(baseChars[0], compositeChars[0],
+                                      aDeadKeyArray)) {
+                    entries++;
+                  }
+                  deadKeyActive = false;
+                  break;
+                case -1: {
+                  // If pressing another dead-key produces different character,
+                  // we should register the dead-key entry with first character
+                  // produced by current key.
+
+                  // First inactivate the dead-key state completely.
+                  deadKeyActive =
+                      EnsureDeadKeyActive(false, aDeadKey, aDeadKeyKbdState);
+                  if (NS_WARN_IF(deadKeyActive)) {
+                    MOZ_LOG(gKeyLog, LogLevel::Error,
+                            ("  failed to deactivating the dead-key state..."));
+                    break;
+                  }
+                  for (int32_t i = 0; i < 5; ++i) {
+                    ret = ::ToUnicodeEx(
+                        virtualKey, 0, kbdState, (LPWSTR)baseChars,
+                        ArrayLength(baseChars), 0, mKeyboardLayout);
+                    if (ret >= 0) {
+                      break;
+                    }
+                  }
+                  if (ret > 0 &&
+                      AddDeadKeyEntry(baseChars[0], compositeChars[0],
+                                      aDeadKeyArray)) {
+                    entries++;
+                  }
+                  // Inactivate dead-key state for current virtual keycode.
+                  EnsureDeadKeyActive(false, virtualKey, kbdState);
+                  break;
+                }
+                default:
+                  NS_WARNING("File a bug for this dead-key handling!");
+                  deadKeyActive = false;
+                  break;
+              }
+            }
+            MOZ_LOG(
+                gKeyLog, LogLevel::Verbose,
+                ("  %s -> %s (%d): DeadKeyEntry(%s, %s) (ret=%d)",
+                 kVirtualKeyName[aDeadKey], kVirtualKeyName[virtualKey], vki,
+                 GetCharacterCodeNames(compositeChars, 1).get(),
+                 ret <= 0
+                     ? "''"
+                     : GetCharacterCodeNames(baseChars, std::min(ret, 5)).get(),
+                 ret));
+            break;
+          }
+          default:
+            // 1. Unexpected dead-key. Dead-key chaining is not supported.
+            // 2. More than one character generated. This is not a valid
+            //    dead-key and base character combination.
+            deadKeyActive = false;
+            MOZ_LOG(
+                gKeyLog, LogLevel::Verbose,
+                ("  %s -> %s (%d): Unsupport dead key type(%s) (ret=%d)",
+                 kVirtualKeyName[aDeadKey], kVirtualKeyName[virtualKey], vki,
+                 ret <= 0
+                     ? "''"
+                     : GetCharacterCodeNames(compositeChars, std::min(ret, 5))
+                           .get(),
+                 ret));
+            break;
+        }
+      }
+    }
+  }
+
+  if (deadKeyActive) {
+    deadKeyActive = EnsureDeadKeyActive(false, aDeadKey, aDeadKeyKbdState);
+  }
+
+  aDeadKeyArray.Sort();
+
+  return entries;
+}
+
+uint32_t KeyboardLayout::ConvertNativeKeyCodeToDOMKeyCode(
+    UINT aNativeKeyCode) const {
+  // Alphabet or Numeric or Numpad or Function keys
+  if ((aNativeKeyCode >= 0x30 && aNativeKeyCode <= 0x39) ||
+      (aNativeKeyCode >= 0x41 && aNativeKeyCode <= 0x5A) ||
+      (aNativeKeyCode >= 0x60 && aNativeKeyCode <= 0x87)) {
+    return static_cast<uint32_t>(aNativeKeyCode);
+  }
+  switch (aNativeKeyCode) {
+    // Following keycodes are same as our DOM keycodes
+    case VK_CANCEL:
+    case VK_BACK:
+    case VK_TAB:
+    case VK_CLEAR:
+    case VK_RETURN:
+    case VK_SHIFT:
+    case VK_CONTROL:
+    case VK_MENU:  // Alt
+    case VK_PAUSE:
+    case VK_CAPITAL:  // CAPS LOCK
+    case VK_KANA:     // same as VK_HANGUL
+    case VK_JUNJA:
+    case VK_FINAL:
+    case VK_HANJA:  // same as VK_KANJI
+    case VK_ESCAPE:
+    case VK_CONVERT:
+    case VK_NONCONVERT:
+    case VK_ACCEPT:
+    case VK_MODECHANGE:
+    case VK_SPACE:
+    case VK_PRIOR:  // PAGE UP
+    case VK_NEXT:   // PAGE DOWN
+    case VK_END:
+    case VK_HOME:
+    case VK_LEFT:
+    case VK_UP:
+    case VK_RIGHT:
+    case VK_DOWN:
+    case VK_SELECT:
+    case VK_PRINT:
+    case VK_EXECUTE:
+    case VK_SNAPSHOT:
+    case VK_INSERT:
+    case VK_DELETE:
+    case VK_APPS:  // Context Menu
+    case VK_SLEEP:
+    case VK_NUMLOCK:
+    case VK_SCROLL:  // SCROLL LOCK
+    case VK_ATTN:    // Attension key of IBM midrange computers, e.g., AS/400
+    case VK_CRSEL:   // Cursor Selection
+    case VK_EXSEL:   // Extend Selection
+    case VK_EREOF:   // Erase EOF key of IBM 3270 keyboard layout
+    case VK_PLAY:
+    case VK_ZOOM:
+    case VK_PA1:  // PA1 key of IBM 3270 keyboard layout
+      return uint32_t(aNativeKeyCode);
+
+    case VK_HELP:
+      return NS_VK_HELP;
+
+    // Windows key should be mapped to a Win keycode
+    // They should be able to be distinguished by DOM3 KeyboardEvent.location
+    case VK_LWIN:
+    case VK_RWIN:
+      return NS_VK_WIN;
+
+    case VK_VOLUME_MUTE:
+      return NS_VK_VOLUME_MUTE;
+    case VK_VOLUME_DOWN:
+      return NS_VK_VOLUME_DOWN;
+    case VK_VOLUME_UP:
+      return NS_VK_VOLUME_UP;
+
+    case VK_LSHIFT:
+    case VK_RSHIFT:
+      return NS_VK_SHIFT;
+
+    case VK_LCONTROL:
+    case VK_RCONTROL:
+      return NS_VK_CONTROL;
+
+    // Note that even if the key is AltGr, we should return NS_VK_ALT for
+    // compatibility with both older Gecko and the other browsers.
+    case VK_LMENU:
+    case VK_RMENU:
+      return NS_VK_ALT;
+
+    // Following keycodes are not defined in our DOM keycodes.
+    case VK_BROWSER_BACK:
+    case VK_BROWSER_FORWARD:
+    case VK_BROWSER_REFRESH:
+    case VK_BROWSER_STOP:
+    case VK_BROWSER_SEARCH:
+    case VK_BROWSER_FAVORITES:
+    case VK_BROWSER_HOME:
+    case VK_MEDIA_NEXT_TRACK:
+    case VK_MEDIA_PREV_TRACK:
+    case VK_MEDIA_STOP:
+    case VK_MEDIA_PLAY_PAUSE:
+    case VK_LAUNCH_MAIL:
+    case VK_LAUNCH_MEDIA_SELECT:
+    case VK_LAUNCH_APP1:
+    case VK_LAUNCH_APP2:
+      return 0;
+
+    // Following OEM specific virtual keycodes should pass through DOM keyCode
+    // for compatibility with the other browsers on Windows.
+
+    // Following OEM specific virtual keycodes are defined for Fujitsu/OASYS.
+    case VK_OEM_FJ_JISHO:
+    case VK_OEM_FJ_MASSHOU:
+    case VK_OEM_FJ_TOUROKU:
+    case VK_OEM_FJ_LOYA:
+    case VK_OEM_FJ_ROYA:
+    // Not sure what means "ICO".
+    case VK_ICO_HELP:
+    case VK_ICO_00:
+    case VK_ICO_CLEAR:
+    // Following OEM specific virtual keycodes are defined for Nokia/Ericsson.
+    case VK_OEM_RESET:
+    case VK_OEM_JUMP:
+    case VK_OEM_PA1:
+    case VK_OEM_PA2:
+    case VK_OEM_PA3:
+    case VK_OEM_WSCTRL:
+    case VK_OEM_CUSEL:
+    case VK_OEM_ATTN:
+    case VK_OEM_FINISH:
+    case VK_OEM_COPY:
+    case VK_OEM_AUTO:
+    case VK_OEM_ENLW:
+    case VK_OEM_BACKTAB:
+    // VK_OEM_CLEAR is defined as not OEM specific, but let's pass though
+    // DOM keyCode like other OEM specific virtual keycodes.
+    case VK_OEM_CLEAR:
+      return uint32_t(aNativeKeyCode);
+
+    // 0xE1 is an OEM specific virtual keycode. However, the value is already
+    // used in our DOM keyCode for AltGr on Linux. So, this virtual keycode
+    // cannot pass through DOM keyCode.
+    case 0xE1:
+      return 0;
+
+    // Following keycodes are OEM keys which are keycodes for non-alphabet and
+    // non-numeric keys, we should compute each keycode of them from unshifted
+    // character which is inputted by each key.  But if the unshifted character
+    // is not an ASCII character but shifted character is an ASCII character,
+    // we should refer it.
+    case VK_OEM_1:
+    case VK_OEM_PLUS:
+    case VK_OEM_COMMA:
+    case VK_OEM_MINUS:
+    case VK_OEM_PERIOD:
+    case VK_OEM_2:
+    case VK_OEM_3:
+    case VK_OEM_4:
+    case VK_OEM_5:
+    case VK_OEM_6:
+    case VK_OEM_7:
+    case VK_OEM_8:
+    case VK_OEM_102:
+    case VK_ABNT_C1: {
+      NS_ASSERTION(IsPrintableCharKey(aNativeKeyCode),
+                   "The key must be printable");
+      ModifierKeyState modKeyState(0);
+      UniCharsAndModifiers uniChars =
+          GetUniCharsAndModifiers(aNativeKeyCode, modKeyState);
+      if (uniChars.Length() != 1 || uniChars.CharAt(0) < ' ' ||
+          uniChars.CharAt(0) > 0x7F) {
+        modKeyState.Set(MODIFIER_SHIFT);
+        uniChars = GetUniCharsAndModifiers(aNativeKeyCode, modKeyState);
+        if (uniChars.Length() != 1 || uniChars.CharAt(0) < ' ' ||
+            uniChars.CharAt(0) > 0x7F) {
+          // In this case, we've returned 0 in this case for long time because
+          // we decided that we should avoid setting same keyCode value to 2 or
+          // more keys since active keyboard layout may have a key to input the
+          // punctuation with different key.  However, setting keyCode to 0
+          // makes some web applications which are aware of neither
+          // KeyboardEvent.key nor KeyboardEvent.code not work with Firefox
+          // when user selects non-ASCII capable keyboard layout such as
+          // Russian and Thai layout.  So, let's decide keyCode value with
+          // major keyboard layout's key which causes the OEM keycode.
+          // Actually, this maps same keyCode value to 2 keys on Russian
+          // keyboard layout.  "Period" key causes VK_OEM_PERIOD but inputs
+          // Yu of Cyrillic and "Slash" key causes VK_OEM_2 (same as US
+          // keyboard layout) but inputs "." (period of ASCII).  Therefore,
+          // we return DOM_VK_PERIOD which is same as VK_OEM_PERIOD for
+          // "Period" key.  On the other hand, we use same keyCode value for
+          // "Slash" key too because it inputs ".".
+          CodeNameIndex code;
+          switch (aNativeKeyCode) {
+            case VK_OEM_1:
+              code = CODE_NAME_INDEX_Semicolon;
+              break;
+            case VK_OEM_PLUS:
+              code = CODE_NAME_INDEX_Equal;
+              break;
+            case VK_OEM_COMMA:
+              code = CODE_NAME_INDEX_Comma;
+              break;
+            case VK_OEM_MINUS:
+              code = CODE_NAME_INDEX_Minus;
+              break;
+            case VK_OEM_PERIOD:
+              code = CODE_NAME_INDEX_Period;
+              break;
+            case VK_OEM_2:
+              code = CODE_NAME_INDEX_Slash;
+              break;
+            case VK_OEM_3:
+              code = CODE_NAME_INDEX_Backquote;
+              break;
+            case VK_OEM_4:
+              code = CODE_NAME_INDEX_BracketLeft;
+              break;
+            case VK_OEM_5:
+              code = CODE_NAME_INDEX_Backslash;
+              break;
+            case VK_OEM_6:
+              code = CODE_NAME_INDEX_BracketRight;
+              break;
+            case VK_OEM_7:
+              code = CODE_NAME_INDEX_Quote;
+              break;
+            case VK_OEM_8:
+              // Use keyCode value for "Backquote" key on UK keyboard layout.
+              code = CODE_NAME_INDEX_Backquote;
+              break;
+            case VK_OEM_102:
+              // Use keyCode value for "IntlBackslash" key.
+              code = CODE_NAME_INDEX_IntlBackslash;
+              break;
+            case VK_ABNT_C1:  // "/" of ABNT.
+              // Use keyCode value for "IntlBackslash" key on ABNT keyboard
+              // layout.
+              code = CODE_NAME_INDEX_IntlBackslash;
+              break;
+            default:
+              MOZ_ASSERT_UNREACHABLE("Handle all OEM keycode values");
+              return 0;
+          }
+          return WidgetKeyboardEvent::GetFallbackKeyCodeOfPunctuationKey(code);
+        }
+      }
+      return WidgetUtils::ComputeKeyCodeFromChar(uniChars.CharAt(0));
+    }
+
+    // IE sets 0xC2 to the DOM keyCode for VK_ABNT_C2.  However, we're already
+    // using NS_VK_SEPARATOR for the separator key on Mac and Linux.  Therefore,
+    // We should keep consistency between Gecko on all platforms rather than
+    // with other browsers since a lot of keyCode values are already different
+    // between browsers.
+    case VK_ABNT_C2:
+      return NS_VK_SEPARATOR;
+
+    // VK_PROCESSKEY means IME already consumed the key event.
+    case VK_PROCESSKEY:
+      return NS_VK_PROCESSKEY;
+    // VK_PACKET is generated by SendInput() API, we don't need to
+    // care this message as key event.
+    case VK_PACKET:
+      return 0;
+    // If a key is not mapped to a virtual keycode, 0xFF is used.
+    case 0xFF:
+      NS_WARNING("The key is failed to be converted to a virtual keycode");
+      return 0;
+  }
+#ifdef DEBUG
+  nsPrintfCString warning(
+      "Unknown virtual keycode (0x%08X), please check the "
+      "latest MSDN document, there may be some new "
+      "keycodes we've never known.",
+      aNativeKeyCode);
+  NS_WARNING(warning.get());
+#endif
+  return 0;
+}
+
+KeyNameIndex KeyboardLayout::ConvertNativeKeyCodeToKeyNameIndex(
+    uint8_t aVirtualKey) const {
+  if (IsPrintableCharKey(aVirtualKey) || aVirtualKey == VK_PACKET) {
+    return KEY_NAME_INDEX_USE_STRING;
+  }
+
+  // If the keyboard layout has AltGr and AltRight key is pressed,
+  // return AltGraph.
+  if (aVirtualKey == VK_RMENU && HasAltGr()) {
+    return KEY_NAME_INDEX_AltGraph;
+  }
+
+  switch (aVirtualKey) {
+#undef NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+#define NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, aKeyNameIndex) \
+  case aNativeKey:                                                     \
+    return aKeyNameIndex;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+
+    default:
+      break;
+  }
+
+  HKL layout = KeyboardLayout::GetLayout();
+  WORD langID = LOWORD(static_cast<HKL>(layout));
+  WORD primaryLangID = PRIMARYLANGID(langID);
+
+  if (primaryLangID == LANG_JAPANESE) {
+    switch (aVirtualKey) {
+#undef NS_JAPANESE_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+#define NS_JAPANESE_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey,    \
+                                                     aKeyNameIndex) \
+  case aNativeKey:                                                  \
+    return aKeyNameIndex;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_JAPANESE_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+
+      default:
+        break;
+    }
+  } else if (primaryLangID == LANG_KOREAN) {
+    switch (aVirtualKey) {
+#undef NS_KOREAN_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+#define NS_KOREAN_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, aKeyNameIndex) \
+  case aNativeKey:                                                            \
+    return aKeyNameIndex;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_KOREAN_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+
+      default:
+        return KEY_NAME_INDEX_Unidentified;
+    }
+  }
+
+  switch (aVirtualKey) {
+#undef NS_OTHER_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+#define NS_OTHER_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX(aNativeKey, aKeyNameIndex) \
+  case aNativeKey:                                                           \
+    return aKeyNameIndex;
+
+#include "NativeKeyToDOMKeyName.h"
+
+#undef NS_OTHER_NATIVE_KEY_TO_DOM_KEY_NAME_INDEX
+
+    default:
+      return KEY_NAME_INDEX_Unidentified;
+  }
+}
+
+// static
+CodeNameIndex KeyboardLayout::ConvertScanCodeToCodeNameIndex(UINT aScanCode) {
+  switch (aScanCode) {
+#define NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX(aNativeKey, aCodeNameIndex) \
+  case aNativeKey:                                                       \
+    return aCodeNameIndex;
+
+#include "NativeKeyToDOMCodeName.h"
+
+#undef NS_NATIVE_KEY_TO_DOM_CODE_NAME_INDEX
+
+    default:
+      return CODE_NAME_INDEX_UNKNOWN;
+  }
+}
+
+nsresult KeyboardLayout::SynthesizeNativeKeyEvent(
+    nsWindow* aWidget, int32_t aNativeKeyboardLayout, int32_t aNativeKeyCode,
+    uint32_t aModifierFlags, const nsAString& aCharacters,
+    const nsAString& aUnmodifiedCharacters) {
+  UINT keyboardLayoutListCount = ::GetKeyboardLayoutList(0, nullptr);
+  NS_ASSERTION(keyboardLayoutListCount > 0,
+               "One keyboard layout must be installed at least");
+  HKL keyboardLayoutListBuff[50];
+  HKL* keyboardLayoutList = keyboardLayoutListCount < 50
+                                ? keyboardLayoutListBuff
+                                : new HKL[keyboardLayoutListCount];
+  keyboardLayoutListCount =
+      ::GetKeyboardLayoutList(keyboardLayoutListCount, keyboardLayoutList);
+  NS_ASSERTION(keyboardLayoutListCount > 0,
+               "Failed to get all keyboard layouts installed on the system");
+
+  nsPrintfCString layoutName("%08x", aNativeKeyboardLayout);
+  HKL loadedLayout = LoadKeyboardLayoutA(layoutName.get(), KLF_NOTELLSHELL);
+  if (loadedLayout == nullptr) {
+    if (keyboardLayoutListBuff != keyboardLayoutList) {
+      delete[] keyboardLayoutList;
+    }
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  // Setup clean key state and load desired layout
+  BYTE originalKbdState[256];
+  ::GetKeyboardState(originalKbdState);
+  BYTE kbdState[256];
+  memset(kbdState, 0, sizeof(kbdState));
+  // This changes the state of the keyboard for the current thread only,
+  // and we'll restore it soon, so this should be OK.
+  ::SetKeyboardState(kbdState);
+
+  OverrideLayout(loadedLayout);
+
+  bool isAltGrKeyPress = false;
+  if (aModifierFlags & nsIWidget::ALTGRAPH) {
+    if (!HasAltGr()) {
+      return NS_ERROR_INVALID_ARG;
+    }
+    // AltGr emulates ControlLeft key press and AltRight key press.
+    // So, we should remove those flags from aModifierFlags before
+    // calling WinUtils::SetupKeyModifiersSequence() to create correct
+    // key sequence.
+    // FYI: We don't support both ControlLeft and AltRight (AltGr) are
+    //      pressed at the same time unless synthesizing key is
+    //      VK_LCONTROL.
+    aModifierFlags &= ~(nsIWidget::CTRL_L | nsIWidget::ALT_R);
+  }
+
+  uint8_t argumentKeySpecific = 0;
+  switch (aNativeKeyCode & 0xFF) {
+    case VK_SHIFT:
+      aModifierFlags &= ~(nsIWidget::SHIFT_L | nsIWidget::SHIFT_R);
+      argumentKeySpecific = VK_LSHIFT;
+      break;
+    case VK_LSHIFT:
+      aModifierFlags &= ~nsIWidget::SHIFT_L;
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_SHIFT;
+      break;
+    case VK_RSHIFT:
+      aModifierFlags &= ~nsIWidget::SHIFT_R;
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_SHIFT;
+      break;
+    case VK_CONTROL:
+      aModifierFlags &= ~(nsIWidget::CTRL_L | nsIWidget::CTRL_R);
+      argumentKeySpecific = VK_LCONTROL;
+      break;
+    case VK_LCONTROL:
+      aModifierFlags &= ~nsIWidget::CTRL_L;
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_CONTROL;
+      break;
+    case VK_RCONTROL:
+      aModifierFlags &= ~nsIWidget::CTRL_R;
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_CONTROL;
+      break;
+    case VK_MENU:
+      aModifierFlags &= ~(nsIWidget::ALT_L | nsIWidget::ALT_R);
+      argumentKeySpecific = VK_LMENU;
+      break;
+    case VK_LMENU:
+      aModifierFlags &= ~nsIWidget::ALT_L;
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_MENU;
+      break;
+    case VK_RMENU:
+      aModifierFlags &= ~(nsIWidget::ALT_R | nsIWidget::ALTGRAPH);
+      argumentKeySpecific = aNativeKeyCode & 0xFF;
+      aNativeKeyCode = (aNativeKeyCode & 0xFFFF0000) | VK_MENU;
+      // If AltRight key is AltGr in the keyboard layout, let's use
+      // SetupKeyModifiersSequence() to emulate the native behavior
+      // since the same event order between keydown and keyup makes
+      // the following code complicated.
+      if (HasAltGr()) {
+        isAltGrKeyPress = true;
+        aModifierFlags &= ~nsIWidget::CTRL_L;
+        aModifierFlags |= nsIWidget::ALTGRAPH;
+      }
+      break;
+    case VK_CAPITAL:
+      aModifierFlags &= ~nsIWidget::CAPS_LOCK;
+      argumentKeySpecific = VK_CAPITAL;
+      break;
+    case VK_NUMLOCK:
+      aModifierFlags &= ~nsIWidget::NUM_LOCK;
+      argumentKeySpecific = VK_NUMLOCK;
+      break;
+  }
+
+  AutoTArray<KeyPair, 10> keySequence;
+  WinUtils::SetupKeyModifiersSequence(&keySequence, aModifierFlags, WM_KEYDOWN);
+  if (!isAltGrKeyPress) {
+    keySequence.AppendElement(KeyPair(aNativeKeyCode, argumentKeySpecific));
+  }
+
+  // Simulate the pressing of each modifier key and then the real key
+  // FYI: Each NativeKey instance here doesn't need to override keyboard layout
+  //      since this method overrides and restores the keyboard layout.
+  for (uint32_t i = 0; i < keySequence.Length(); ++i) {
+    uint8_t key = keySequence[i].mGeneral;
+    uint8_t keySpecific = keySequence[i].mSpecific;
+    uint16_t scanCode = keySequence[i].mScanCode;
+    kbdState[key] = 0x81;  // key is down and toggled on if appropriate
+    if (keySpecific) {
+      kbdState[keySpecific] = 0x81;
+    }
+    ::SetKeyboardState(kbdState);
+    ModifierKeyState modKeyState;
+    // If scan code isn't specified explicitly, let's compute it with current
+    // keyboard layout.
+    if (!scanCode) {
+      scanCode =
+          ComputeScanCodeForVirtualKeyCode(keySpecific ? keySpecific : key);
+    }
+    LPARAM lParam = static_cast<LPARAM>(scanCode << 16);
+    // If the scan code is for an extended key, set extended key flag.
+    if ((scanCode & 0xFF00) == 0xE000) {
+      lParam |= 0x1000000;
+    }
+    // When AltGr key is pressed, both ControlLeft and AltRight cause
+    // WM_KEYDOWN messages.
+    bool makeSysKeyMsg =
+        !(aModifierFlags & nsIWidget::ALTGRAPH) && IsSysKey(key, modKeyState);
+    MSG keyDownMsg =
+        WinUtils::InitMSG(makeSysKeyMsg ? WM_SYSKEYDOWN : WM_KEYDOWN, key,
+                          lParam, aWidget->GetWindowHandle());
+    if (i == keySequence.Length() - 1) {
+      bool makeDeadCharMsg =
+          (IsDeadKey(key, modKeyState) && aCharacters.IsEmpty());
+      nsAutoString chars(aCharacters);
+      if (makeDeadCharMsg) {
+        UniCharsAndModifiers deadChars =
+            GetUniCharsAndModifiers(key, modKeyState);
+        chars = deadChars.ToString();
+        NS_ASSERTION(chars.Length() == 1,
+                     "Dead char must be only one character");
+      }
+      if (chars.IsEmpty()) {
+        NativeKey nativeKey(aWidget, keyDownMsg, modKeyState);
+        nativeKey.HandleKeyDownMessage();
+      } else {
+        AutoTArray<NativeKey::FakeCharMsg, 10> fakeCharMsgs;
+        for (uint32_t j = 0; j < chars.Length(); j++) {
+          NativeKey::FakeCharMsg* fakeCharMsg = fakeCharMsgs.AppendElement();
+          fakeCharMsg->mCharCode = chars.CharAt(j);
+          fakeCharMsg->mScanCode = scanCode;
+          fakeCharMsg->mIsSysKey = makeSysKeyMsg;
+          fakeCharMsg->mIsDeadKey = makeDeadCharMsg;
+        }
+        NativeKey nativeKey(aWidget, keyDownMsg, modKeyState, 0, &fakeCharMsgs);
+        bool dispatched;
+        nativeKey.HandleKeyDownMessage(&dispatched);
+        // If some char messages are not consumed, let's emulate the widget
+        // receiving the message directly.
+        for (uint32_t j = 1; j < fakeCharMsgs.Length(); j++) {
+          if (fakeCharMsgs[j].mConsumed) {
+            continue;
+          }
+          MSG charMsg = fakeCharMsgs[j].GetCharMsg(aWidget->GetWindowHandle());
+          NativeKey nativeKey(aWidget, charMsg, modKeyState);
+          nativeKey.HandleCharMessage(charMsg);
+        }
+      }
+    } else {
+      NativeKey nativeKey(aWidget, keyDownMsg, modKeyState);
+      nativeKey.HandleKeyDownMessage();
+    }
+  }
+
+  keySequence.Clear();
+  if (!isAltGrKeyPress) {
+    keySequence.AppendElement(KeyPair(aNativeKeyCode, argumentKeySpecific));
+  }
+  WinUtils::SetupKeyModifiersSequence(&keySequence, aModifierFlags, WM_KEYUP);
+  for (uint32_t i = 0; i < keySequence.Length(); ++i) {
+    uint8_t key = keySequence[i].mGeneral;
+    uint8_t keySpecific = keySequence[i].mSpecific;
+    uint16_t scanCode = keySequence[i].mScanCode;
+    kbdState[key] = 0;  // key is up and toggled off if appropriate
+    if (keySpecific) {
+      kbdState[keySpecific] = 0;
+    }
+    ::SetKeyboardState(kbdState);
+    ModifierKeyState modKeyState;
+    // If scan code isn't specified explicitly, let's compute it with current
+    // keyboard layout.
+    if (!scanCode) {
+      scanCode =
+          ComputeScanCodeForVirtualKeyCode(keySpecific ? keySpecific : key);
+    }
+    LPARAM lParam = static_cast<LPARAM>(scanCode << 16);
+    // If the scan code is for an extended key, set extended key flag.
+    if ((scanCode & 0xFF00) == 0xE000) {
+      lParam |= 0x1000000;
+    }
+    // Don't use WM_SYSKEYUP for Alt keyup.
+    // NOTE: When AltGr was pressed, ControlLeft causes WM_SYSKEYUP normally.
+    bool makeSysKeyMsg = IsSysKey(key, modKeyState) && key != VK_MENU;
+    MSG keyUpMsg = WinUtils::InitMSG(makeSysKeyMsg ? WM_SYSKEYUP : WM_KEYUP,
+                                     key, lParam, aWidget->GetWindowHandle());
+    NativeKey nativeKey(aWidget, keyUpMsg, modKeyState);
+    nativeKey.HandleKeyUpMessage();
+  }
+
+  // Restore old key state and layout
+  ::SetKeyboardState(originalKbdState);
+  RestoreLayout();
+
+  // Don't unload the layout if it's installed actually.
+  for (uint32_t i = 0; i < keyboardLayoutListCount; i++) {
+    if (keyboardLayoutList[i] == loadedLayout) {
+      loadedLayout = 0;
+      break;
+    }
+  }
+  if (keyboardLayoutListBuff != keyboardLayoutList) {
+    delete[] keyboardLayoutList;
+  }
+  if (loadedLayout) {
+    ::UnloadKeyboardLayout(loadedLayout);
+  }
+  return NS_OK;
+}
+
+/*****************************************************************************
+ * mozilla::widget::DeadKeyTable
+ *****************************************************************************/
+
+char16_t DeadKeyTable::GetCompositeChar(char16_t aBaseChar) const {
+  // Dead-key table is sorted by BaseChar in ascending order.
+  // Usually they are too small to use binary search.
+
+  for (uint32_t index = 0; index < mEntries; index++) {
+    if (mTable[index].BaseChar == aBaseChar) {
+      return mTable[index].CompositeChar;
+    }
+    if (mTable[index].BaseChar > aBaseChar) {
+      break;
+    }
+  }
+
+  return 0;
+}
+
+/*****************************************************************************
+ * mozilla::widget::RedirectedKeyDownMessage
+ *****************************************************************************/
+
+MSG RedirectedKeyDownMessageManager::sRedirectedKeyDownMsg;
+bool RedirectedKeyDownMessageManager::sDefaultPreventedOfRedirectedMsg = false;
+
+// static
+bool RedirectedKeyDownMessageManager::IsRedirectedMessage(const MSG& aMsg) {
+  return (aMsg.message == WM_KEYDOWN || aMsg.message == WM_SYSKEYDOWN) &&
+         (sRedirectedKeyDownMsg.message == aMsg.message &&
+          WinUtils::GetScanCode(sRedirectedKeyDownMsg.lParam) ==
+              WinUtils::GetScanCode(aMsg.lParam));
+}
+
+// static
+void RedirectedKeyDownMessageManager::RemoveNextCharMessage(HWND aWnd) {
+  MSG msg;
+  if (WinUtils::PeekMessage(&msg, aWnd, WM_KEYFIRST, WM_KEYLAST,
+                            PM_NOREMOVE | PM_NOYIELD) &&
+      (msg.message == WM_CHAR || msg.message == WM_SYSCHAR)) {
+    WinUtils::PeekMessage(&msg, aWnd, msg.message, msg.message,
+                          PM_REMOVE | PM_NOYIELD);
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/KeyboardLayout.h b/widget/windows/KeyboardLayout.h
new file mode 100644
index 0000000000..5d430dbea0
--- /dev/null
+++ b/widget/windows/KeyboardLayout.h
@@ -0,0 +1,1156 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef KeyboardLayout_h__
+#define KeyboardLayout_h__
+
+#include "mozilla/RefPtr.h"
+#include "nscore.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "nsWindow.h"
+#include "nsWindowDefs.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/widget/WinMessages.h"
+#include "mozilla/widget/WinModifierKeyState.h"
+#include <windows.h>
+
+#define NS_NUM_OF_KEYS 70
+
+#define VK_OEM_1 0xBA     // ';:' for US
+#define VK_OEM_PLUS 0xBB  // '+' any country
+#define VK_OEM_COMMA 0xBC
+#define VK_OEM_MINUS 0xBD  // '-' any country
+#define VK_OEM_PERIOD 0xBE
+#define VK_OEM_2 0xBF
+#define VK_OEM_3 0xC0
+// '/?' for Brazilian (ABNT)
+#define VK_ABNT_C1 0xC1
+// Separator in Numpad for Brazilian (ABNT) or JIS keyboard for Mac.
+#define VK_ABNT_C2 0xC2
+#define VK_OEM_4 0xDB
+#define VK_OEM_5 0xDC
+#define VK_OEM_6 0xDD
+#define VK_OEM_7 0xDE
+#define VK_OEM_8 0xDF
+#define VK_OEM_102 0xE2
+#define VK_OEM_CLEAR 0xFE
+
+class nsIUserIdleServiceInternal;
+
+namespace mozilla {
+namespace widget {
+
+enum ScanCode : uint16_t {
+  eCapsLock = 0x003A,
+  eNumLock = 0xE045,
+  eShiftLeft = 0x002A,
+  eShiftRight = 0x0036,
+  eControlLeft = 0x001D,
+  eControlRight = 0xE01D,
+  eAltLeft = 0x0038,
+  eAltRight = 0xE038,
+};
+
+// 0: nsIWidget's native modifier flag
+// 1: Virtual keycode which does not distinguish whether left or right location.
+// 2: Virtual keycode which distinguishes whether left or right location.
+// 3: Scan code.
+static const uint32_t sModifierKeyMap[][4] = {
+    {nsIWidget::CAPS_LOCK, VK_CAPITAL, 0, ScanCode::eCapsLock},
+    {nsIWidget::NUM_LOCK, VK_NUMLOCK, 0, ScanCode::eNumLock},
+    {nsIWidget::SHIFT_L, VK_SHIFT, VK_LSHIFT, ScanCode::eShiftLeft},
+    {nsIWidget::SHIFT_R, VK_SHIFT, VK_RSHIFT, ScanCode::eShiftRight},
+    {nsIWidget::CTRL_L, VK_CONTROL, VK_LCONTROL, ScanCode::eControlLeft},
+    {nsIWidget::CTRL_R, VK_CONTROL, VK_RCONTROL, ScanCode::eControlRight},
+    {nsIWidget::ALT_L, VK_MENU, VK_LMENU, ScanCode::eAltLeft},
+    {nsIWidget::ALT_R, VK_MENU, VK_RMENU, ScanCode::eAltRight}};
+
+class KeyboardLayout;
+
+class MOZ_STACK_CLASS UniCharsAndModifiers final {
+ public:
+  UniCharsAndModifiers() {}
+  UniCharsAndModifiers operator+(const UniCharsAndModifiers& aOther) const;
+  UniCharsAndModifiers& operator+=(const UniCharsAndModifiers& aOther);
+
+  /**
+   * Append a pair of unicode character and the final modifier.
+   */
+  void Append(char16_t aUniChar, Modifiers aModifiers);
+  void Clear() {
+    mChars.Truncate();
+    mModifiers.Clear();
+  }
+  bool IsEmpty() const {
+    MOZ_ASSERT(mChars.Length() == mModifiers.Length());
+    return mChars.IsEmpty();
+  }
+
+  char16_t CharAt(size_t aIndex) const {
+    MOZ_ASSERT(aIndex < Length());
+    return mChars[aIndex];
+  }
+  Modifiers ModifiersAt(size_t aIndex) const {
+    MOZ_ASSERT(aIndex < Length());
+    return mModifiers[aIndex];
+  }
+  size_t Length() const {
+    MOZ_ASSERT(mChars.Length() == mModifiers.Length());
+    return mChars.Length();
+  }
+
+  bool IsProducingCharsWithAltGr() const {
+    return !IsEmpty() && (ModifiersAt(0) & MODIFIER_ALTGRAPH) != 0;
+  }
+
+  void FillModifiers(Modifiers aModifiers);
+  /**
+   * OverwriteModifiersIfBeginsWith() assigns mModifiers with aOther between
+   * [0] and [aOther.mLength - 1] only when mChars begins with aOther.mChars.
+   */
+  void OverwriteModifiersIfBeginsWith(const UniCharsAndModifiers& aOther);
+
+  bool UniCharsEqual(const UniCharsAndModifiers& aOther) const;
+  bool UniCharsCaseInsensitiveEqual(const UniCharsAndModifiers& aOther) const;
+  bool BeginsWith(const UniCharsAndModifiers& aOther) const;
+
+  const nsString& ToString() const { return mChars; }
+
+ private:
+  nsAutoString mChars;
+  // 5 is enough number for normal keyboard layout handling.  On Windows,
+  // a dead key sequence may cause inputting up to 5 characters per key press.
+  CopyableAutoTArray<Modifiers, 5> mModifiers;
+};
+
+struct DeadKeyEntry {
+  char16_t BaseChar;
+  char16_t CompositeChar;
+
+  DeadKeyEntry(char16_t aBaseChar, char16_t aCompositeChar)
+      : BaseChar(aBaseChar), CompositeChar(aCompositeChar) {}
+
+  bool operator<(const DeadKeyEntry& aOther) const {
+    return this->BaseChar < aOther.BaseChar;
+  }
+
+  bool operator==(const DeadKeyEntry& aOther) const {
+    return this->BaseChar == aOther.BaseChar;
+  }
+};
+
+class DeadKeyTable {
+  friend class KeyboardLayout;
+
+  uint16_t mEntries;
+  // KeyboardLayout::AddDeadKeyTable() will allocate as many entries as
+  // required.  It is the only way to create new DeadKeyTable instances.
+  DeadKeyEntry mTable[1];
+
+  void Init(const DeadKeyEntry* aDeadKeyArray, uint32_t aEntries) {
+    mEntries = aEntries;
+    memcpy(mTable, aDeadKeyArray, aEntries * sizeof(DeadKeyEntry));
+  }
+
+  static uint32_t SizeInBytes(uint32_t aEntries) {
+    return offsetof(DeadKeyTable, mTable) + aEntries * sizeof(DeadKeyEntry);
+  }
+
+ public:
+  uint32_t Entries() const { return mEntries; }
+
+  bool IsEqual(const DeadKeyEntry* aDeadKeyArray, uint32_t aEntries) const {
+    return (mEntries == aEntries &&
+            !memcmp(mTable, aDeadKeyArray, aEntries * sizeof(DeadKeyEntry)));
+  }
+
+  char16_t GetCompositeChar(char16_t aBaseChar) const;
+};
+
+class VirtualKey {
+ public:
+  enum ShiftStateIndex : uint8_t {
+    //  0 - Normal
+    eNormal = 0,
+    //  1 - Shift
+    eShift,
+    //  2 - Control
+    eControl,
+    //  3 - Control + Shift
+    eControlShift,
+    //  4 - Alt
+    eAlt,
+    //  5 - Alt + Shift
+    eAltShift,
+    //  6 - Alt + Control (AltGr)
+    eAltGr,
+    //  7 - Alt + Control + Shift (AltGr + Shift)
+    eAltGrShift,
+    //  8 - CapsLock
+    eWithCapsLock,
+    //  9 - CapsLock + Shift
+    eShiftWithCapsLock,
+    // 10 - CapsLock + Control
+    eControlWithCapsLock,
+    // 11 - CapsLock + Control + Shift
+    eControlShiftWithCapsLock,
+    // 12 - CapsLock + Alt
+    eAltWithCapsLock,
+    // 13 - CapsLock + Alt + Shift
+    eAltShiftWithCapsLock,
+    // 14 - CapsLock + Alt + Control (CapsLock + AltGr)
+    eAltGrWithCapsLock,
+    // 15 - CapsLock + Alt + Control + Shift (CapsLock + AltGr + Shift)
+    eAltGrShiftWithCapsLock,
+  };
+
+  enum ShiftStateFlag {
+    STATE_SHIFT = 0x01,
+    STATE_CONTROL = 0x02,
+    STATE_ALT = 0x04,
+    STATE_CAPSLOCK = 0x08,
+    // ShiftState needs to have AltGr state separately since this is necessary
+    // for lossless conversion with Modifiers.
+    STATE_ALTGRAPH = 0x80,
+    // Useful to remove or check Ctrl and Alt flags.
+    STATE_CONTROL_ALT = STATE_CONTROL | STATE_ALT,
+  };
+
+  typedef uint8_t ShiftState;
+
+  static ShiftState ModifiersToShiftState(Modifiers aModifiers);
+  static ShiftState ModifierKeyStateToShiftState(
+      const ModifierKeyState& aModKeyState) {
+    return ModifiersToShiftState(aModKeyState.GetModifiers());
+  }
+  static Modifiers ShiftStateToModifiers(ShiftState aShiftState);
+  static bool IsAltGrIndex(uint8_t aIndex) {
+    return (aIndex & STATE_CONTROL_ALT) == STATE_CONTROL_ALT;
+  }
+
+ private:
+  union KeyShiftState {
+    struct {
+      char16_t Chars[4];
+    } Normal;
+    struct {
+      const DeadKeyTable* Table;
+      char16_t DeadChar;
+    } DeadKey;
+  };
+
+  KeyShiftState mShiftStates[16];
+  uint16_t mIsDeadKey;
+
+  static uint8_t ToShiftStateIndex(ShiftState aShiftState) {
+    if (!(aShiftState & STATE_ALTGRAPH)) {
+      MOZ_ASSERT(aShiftState <= eAltGrShiftWithCapsLock);
+      return static_cast<uint8_t>(aShiftState);
+    }
+    uint8_t index = aShiftState & ~STATE_ALTGRAPH;
+    index |= (STATE_ALT | STATE_CONTROL);
+    MOZ_ASSERT(index <= eAltGrShiftWithCapsLock);
+    return index;
+  }
+
+  void SetDeadKey(ShiftState aShiftState, bool aIsDeadKey) {
+    if (aIsDeadKey) {
+      mIsDeadKey |= 1 << ToShiftStateIndex(aShiftState);
+    } else {
+      mIsDeadKey &= ~(1 << ToShiftStateIndex(aShiftState));
+    }
+  }
+
+ public:
+  static void FillKbdState(PBYTE aKbdState, const ShiftState aShiftState);
+
+  bool IsDeadKey(ShiftState aShiftState) const {
+    return (mIsDeadKey & (1 << ToShiftStateIndex(aShiftState))) != 0;
+  }
+
+  /**
+   * IsChangedByAltGr() is useful to check if a key with AltGr produces
+   * different character(s) from the key without AltGr.
+   * Note that this is designed for checking if a keyboard layout has AltGr
+   * key.  So, this result may not exactly correct for the key since it's
+   * okay to fails in some edge cases when we check all keys which produce
+   * character(s) in a layout.
+   */
+  bool IsChangedByAltGr(ShiftState aShiftState) const {
+    MOZ_ASSERT(aShiftState == ToShiftStateIndex(aShiftState));
+    MOZ_ASSERT(IsAltGrIndex(aShiftState));
+    MOZ_ASSERT(IsDeadKey(aShiftState) ||
+               mShiftStates[aShiftState].Normal.Chars[0]);
+    const ShiftState kShiftStateWithoutAltGr =
+        aShiftState - ShiftStateIndex::eAltGr;
+    if (IsDeadKey(aShiftState) != IsDeadKey(kShiftStateWithoutAltGr)) {
+      return false;
+    }
+    if (IsDeadKey(aShiftState)) {
+      return mShiftStates[aShiftState].DeadKey.DeadChar !=
+             mShiftStates[kShiftStateWithoutAltGr].DeadKey.DeadChar;
+    }
+    for (size_t i = 0; i < 4; i++) {
+      if (mShiftStates[aShiftState].Normal.Chars[i] !=
+          mShiftStates[kShiftStateWithoutAltGr].Normal.Chars[i]) {
+        return true;
+      }
+      if (!mShiftStates[aShiftState].Normal.Chars[i] &&
+          !mShiftStates[kShiftStateWithoutAltGr].Normal.Chars[i]) {
+        return false;
+      }
+    }
+    return false;
+  }
+
+  void AttachDeadKeyTable(ShiftState aShiftState,
+                          const DeadKeyTable* aDeadKeyTable) {
+    MOZ_ASSERT(aShiftState == ToShiftStateIndex(aShiftState));
+    mShiftStates[aShiftState].DeadKey.Table = aDeadKeyTable;
+  }
+
+  void SetNormalChars(ShiftState aShiftState, const char16_t* aChars,
+                      uint32_t aNumOfChars);
+  void SetDeadChar(ShiftState aShiftState, char16_t aDeadChar);
+  const DeadKeyTable* MatchingDeadKeyTable(const DeadKeyEntry* aDeadKeyArray,
+                                           uint32_t aEntries) const;
+  inline char16_t GetCompositeChar(ShiftState aShiftState,
+                                   char16_t aBaseChar) const {
+    return mShiftStates[ToShiftStateIndex(aShiftState)]
+        .DeadKey.Table->GetCompositeChar(aBaseChar);
+  }
+
+  char16_t GetCompositeChar(const ModifierKeyState& aModKeyState,
+                            char16_t aBaseChar) const {
+    return GetCompositeChar(ModifierKeyStateToShiftState(aModKeyState),
+                            aBaseChar);
+  }
+
+  /**
+   * GetNativeUniChars() returns character(s) which is produced by the
+   * key with given modifiers.  This does NOT return proper MODIFIER_ALTGRAPH
+   * state because this is raw accessor of the database of this key.
+   */
+  UniCharsAndModifiers GetNativeUniChars(ShiftState aShiftState) const;
+  UniCharsAndModifiers GetNativeUniChars(
+      const ModifierKeyState& aModKeyState) const {
+    return GetNativeUniChars(ModifierKeyStateToShiftState(aModKeyState));
+  }
+
+  /**
+   * GetUniChars() returns characters and modifiers which are not consumed
+   * to input the character.
+   * For example, if you specify Ctrl key but the key produces no character
+   * with Ctrl, this returns character(s) which is produced by the key
+   * without Ctrl.  So, the result is useful to decide KeyboardEvent.key
+   * value.
+   * Another example is, if you specify Ctrl key and the key produces
+   * different character(s) from the case without Ctrl key, this returns
+   * the character(s) *without* MODIFIER_CONTROL.  This modifier information
+   * is useful for eKeyPress since TextEditor does not treat eKeyPress events
+   * whose modifier includes MODIFIER_ALT and/or MODIFIER_CONTROL.
+   *
+   * @param aShiftState         Modifiers which you want to retrieve
+   *                            KeyboardEvent.key value for the key with.
+   *                            If AltGr key is pressed, this should include
+   *                            STATE_ALTGRAPH and should NOT include
+   *                            STATE_ALT nor STATE_CONTROL.
+   *                            If both Alt and Ctrl are pressed to emulate
+   *                            AltGr, this should include both STATE_ALT and
+   *                            STATE_CONTROL but should NOT include
+   *                            MODIFIER_ALTGRAPH.
+   *                            Then, this returns proper modifiers when
+   *                            this key produces no character with AltGr.
+   */
+  UniCharsAndModifiers GetUniChars(ShiftState aShiftState) const;
+  UniCharsAndModifiers GetUniChars(const ModifierKeyState& aModKeyState) const {
+    return GetUniChars(ModifierKeyStateToShiftState(aModKeyState));
+  }
+};
+
+class MOZ_STACK_CLASS NativeKey final {
+  friend class KeyboardLayout;
+
+ public:
+  struct FakeCharMsg {
+    UINT mCharCode;
+    UINT mScanCode;
+    bool mIsSysKey;
+    bool mIsDeadKey;
+    bool mConsumed;
+
+    FakeCharMsg()
+        : mCharCode(0),
+          mScanCode(0),
+          mIsSysKey(false),
+          mIsDeadKey(false),
+          mConsumed(false) {}
+
+    MSG GetCharMsg(HWND aWnd) const {
+      MSG msg;
+      msg.hwnd = aWnd;
+      msg.message = mIsDeadKey && mIsSysKey ? WM_SYSDEADCHAR
+                    : mIsDeadKey            ? WM_DEADCHAR
+                    : mIsSysKey             ? WM_SYSCHAR
+                                            : WM_CHAR;
+      msg.wParam = static_cast<WPARAM>(mCharCode);
+      msg.lParam = static_cast<LPARAM>(mScanCode << 16);
+      msg.time = 0;
+      msg.pt.x = msg.pt.y = 0;
+      return msg;
+    }
+  };
+
+  NativeKey(nsWindow* aWidget, const MSG& aMessage,
+            const ModifierKeyState& aModKeyState,
+            HKL aOverrideKeyboardLayout = 0,
+            nsTArray<FakeCharMsg>* aFakeCharMsgs = nullptr);
+
+  ~NativeKey();
+
+  /**
+   * Handle WM_KEYDOWN message or WM_SYSKEYDOWN message.  The instance must be
+   * initialized with WM_KEYDOWN or WM_SYSKEYDOWN.
+   * Returns true if dispatched keydown event or keypress event is consumed.
+   * Otherwise, false.
+   */
+  bool HandleKeyDownMessage(bool* aEventDispatched = nullptr) const;
+
+  /**
+   * Handles WM_CHAR message or WM_SYSCHAR message.  The instance must be
+   * initialized with them.
+   * Returns true if dispatched keypress event is consumed.  Otherwise, false.
+   */
+  bool HandleCharMessage(bool* aEventDispatched = nullptr) const;
+
+  /**
+   * Handles keyup message.  Returns true if the event is consumed.
+   * Otherwise, false.
+   */
+  bool HandleKeyUpMessage(bool* aEventDispatched = nullptr) const;
+
+  /**
+   * Handles WM_APPCOMMAND message.  Returns true if the event is consumed.
+   * Otherwise, false.
+   */
+  bool HandleAppCommandMessage() const;
+
+  /**
+   * Callback of TextEventDispatcherListener::WillDispatchKeyboardEvent().
+   * This method sets alternative char codes of aKeyboardEvent.
+   */
+  void WillDispatchKeyboardEvent(WidgetKeyboardEvent& aKeyboardEvent,
+                                 uint32_t aIndex);
+
+  /**
+   * Returns true if aChar is a control character which shouldn't be inputted
+   * into focused text editor.
+   */
+  static bool IsControlChar(char16_t aChar);
+
+  bool IsShift() const { return mModKeyState.IsShift(); }
+  bool IsControl() const { return mModKeyState.IsControl(); }
+  bool IsAlt() const { return mModKeyState.IsAlt(); }
+  bool MaybeEmulatingAltGraph() const;
+  Modifiers GetModifiers() const { return mModKeyState.GetModifiers(); }
+  const ModifierKeyState& ModifierKeyStateRef() const { return mModKeyState; }
+  VirtualKey::ShiftState GetShiftState() const {
+    return VirtualKey::ModifierKeyStateToShiftState(mModKeyState);
+  }
+
+  /**
+   * GenericVirtualKeyCode() returns virtual keycode which cannot distinguish
+   * position of modifier keys.  E.g., VK_CONTROL for both ControlLeft and
+   * ControlRight.
+   */
+  uint8_t GenericVirtualKeyCode() const { return mOriginalVirtualKeyCode; }
+
+  /**
+   * SpecificVirtualKeyCode() returns virtual keycode which can distinguish
+   * position of modifier keys.  E.g., returns VK_LCONTROL or VK_RCONTROL
+   * instead of VK_CONTROL.  If the key message is synthesized with not
+   * enough information, this prefers left position's keycode.
+   */
+  uint8_t SpecificVirtualKeyCode() const { return mVirtualKeyCode; }
+
+ private:
+  NativeKey* mLastInstance;
+  // mRemovingMsg is set at removing a char message from
+  // GetFollowingCharMessage().
+  MSG mRemovingMsg;
+  // mReceivedMsg is set when another instance starts to handle the message
+  // unexpectedly.
+  MSG mReceivedMsg;
+  RefPtr<nsWindow> mWidget;
+  RefPtr<TextEventDispatcher> mDispatcher;
+  HKL mKeyboardLayout;
+  MSG mMsg;
+  // mFollowingCharMsgs stores WM_CHAR, WM_SYSCHAR, WM_DEADCHAR or
+  // WM_SYSDEADCHAR message which follows WM_KEYDOWN.
+  // Note that the stored messaged are already removed from the queue.
+  // FYI: 5 is enough number for usual keyboard layout handling.  On Windows,
+  // a dead key sequence may cause inputting up to 5 characters per key press.
+  AutoTArray<MSG, 5> mFollowingCharMsgs;
+  // mRemovedOddCharMsgs stores WM_CHAR messages which are caused by ATOK or
+  // WXG (they are Japanese IME) when the user tries to do "Kakutei-undo"
+  // (it means "undo the last commit").
+  nsTArray<MSG> mRemovedOddCharMsgs;
+  // If dispatching eKeyDown or eKeyPress event causes focus change,
+  // the instance shouldn't handle remaning char messages.  For checking it,
+  // this should store first focused window.
+  HWND mFocusedWndBeforeDispatch;
+
+  uint32_t mDOMKeyCode;
+  KeyNameIndex mKeyNameIndex;
+  CodeNameIndex mCodeNameIndex;
+
+  ModifierKeyState mModKeyState;
+
+  // mVirtualKeyCode distinguishes left key or right key of modifier key.
+  uint8_t mVirtualKeyCode;
+  // mOriginalVirtualKeyCode doesn't distinguish left key or right key of
+  // modifier key.  However, if the given keycode is VK_PROCESS, it's resolved
+  // to a keycode before it's handled by IME.
+  uint8_t mOriginalVirtualKeyCode;
+
+  // mCommittedChars indicates the inputted characters which is committed by
+  // the key.  If dead key fail to composite a character, mCommittedChars
+  // indicates both the dead characters and the base characters.
+  UniCharsAndModifiers mCommittedCharsAndModifiers;
+
+  // Following strings are computed by
+  // ComputeInputtingStringWithKeyboardLayout() which is typically called
+  // before dispatching keydown event.
+  // mInputtingStringAndModifiers's string is the string to be
+  // inputted into the focused editor and its modifier state is proper
+  // modifier state for inputting the string into the editor.
+  UniCharsAndModifiers mInputtingStringAndModifiers;
+  // mShiftedString is the string to be inputted into the editor with
+  // current modifier state with active shift state.
+  UniCharsAndModifiers mShiftedString;
+  // mUnshiftedString is the string to be inputted into the editor with
+  // current modifier state without shift state.
+  UniCharsAndModifiers mUnshiftedString;
+  // Following integers are computed by
+  // ComputeInputtingStringWithKeyboardLayout() which is typically called
+  // before dispatching keydown event.  The meaning of these values is same
+  // as charCode.
+  uint32_t mShiftedLatinChar;
+  uint32_t mUnshiftedLatinChar;
+
+  WORD mScanCode;
+  bool mIsExtended;
+  // mIsRepeat is true if the key message is caused by the auto-repeat
+  // feature.
+  bool mIsRepeat;
+  bool mIsDeadKey;
+  // mIsPrintableKey is true if the key may be a printable key without
+  // any modifier keys.  Otherwise, false.
+  // Please note that the event may not cause any text input even if this
+  // is true.  E.g., it might be dead key state or Ctrl key may be pressed.
+  bool mIsPrintableKey;
+  // mIsSkippableInRemoteProcess is false if the key event shouldn't be
+  // skipped in the remote process even if it's too old event.
+  bool mIsSkippableInRemoteProcess;
+  // mCharMessageHasGone is true if the message is a keydown message and
+  // it's followed by at least one char message but it's gone at removing
+  // from the queue.  This could occur if PeekMessage() or something is
+  // hooked by odd tool.
+  bool mCharMessageHasGone;
+  // mIsOverridingKeyboardLayout is true if the instance temporarily overriding
+  // keyboard layout with specified by the constructor.
+  bool mIsOverridingKeyboardLayout;
+  // mCanIgnoreModifierStateAtKeyPress is true if it's allowed to remove
+  // Ctrl or Alt modifier state at dispatching eKeyPress.
+  bool mCanIgnoreModifierStateAtKeyPress;
+
+  nsTArray<FakeCharMsg>* mFakeCharMsgs;
+
+  // When a keydown event is dispatched at handling WM_APPCOMMAND, the computed
+  // virtual keycode is set to this.  Even if we consume WM_APPCOMMAND message,
+  // Windows may send WM_KEYDOWN and WM_KEYUP message for them.
+  // At that time, we should not dispatch key events for them.
+  static uint8_t sDispatchedKeyOfAppCommand;
+
+  NativeKey() {
+    MOZ_CRASH("The default constructor of NativeKey isn't available");
+  }
+
+  void InitWithAppCommand();
+  void InitWithKeyOrChar();
+
+  /**
+   * InitIsSkippableForKeyOrChar() initializes mIsSkippableInRemoteProcess with
+   * mIsRepeat and previous key message information.  So, this must be called
+   * after mIsRepeat is initialized.
+   */
+  void InitIsSkippableForKeyOrChar(const MSG& aLastKeyMSG);
+
+  /**
+   * InitCommittedCharsAndModifiersWithFollowingCharMessages() initializes
+   * mCommittedCharsAndModifiers with mFollowingCharMsgs and mModKeyState.
+   * If mFollowingCharMsgs includes non-printable char messages, they are
+   * ignored (skipped).
+   */
+  void InitCommittedCharsAndModifiersWithFollowingCharMessages();
+
+  UINT GetScanCodeWithExtendedFlag() const;
+
+  // The result is one of eKeyLocation*.
+  uint32_t GetKeyLocation() const;
+
+  /**
+   * RemoveFollowingOddCharMessages() removes odd WM_CHAR messages from the
+   * queue when IsIMEDoingKakuteiUndo() returns true.
+   */
+  void RemoveFollowingOddCharMessages();
+
+  /**
+   * "Kakutei-Undo" of ATOK or WXG (both of them are Japanese IME) causes
+   * strange WM_KEYDOWN/WM_KEYUP/WM_CHAR message pattern.  So, when this
+   * returns true, the caller needs to be careful for processing the messages.
+   */
+  bool IsIMEDoingKakuteiUndo() const;
+
+  /**
+   * This returns true if user types a number key in numpad with Alt key
+   * to input a Unicode character from its scalar value.
+   * Note that inputting Unicode scalar value is available without NumLock.
+   * Therefore, this returns true even if user presses a function key on
+   * numpad without NumLock, but that may be intended to perform a shortcut
+   * key like Alt + Home.
+   */
+  bool MaybeTypingUnicodeScalarValue() const {
+    return !mIsExtended && IsSysKeyDownOrKeyUpMessage() && IsAlt() &&
+           !IsControl() && !IsShift() &&
+           ((mScanCode >= 0x004F && mScanCode <= 0x0052) ||  // Numpad0-3
+            (mScanCode >= 0x004B && mScanCode <= 0x004D) ||  // Numpad4-6
+            (mScanCode >= 0x0047 && mScanCode <= 0x0049));   // Numpad7-9
+  }
+
+  bool IsKeyDownMessage() const {
+    return mMsg.message == WM_KEYDOWN || mMsg.message == WM_SYSKEYDOWN;
+  }
+  bool IsKeyUpMessage() const {
+    return mMsg.message == WM_KEYUP || mMsg.message == WM_SYSKEYUP;
+  }
+  bool IsSysKeyDownOrKeyUpMessage() const {
+    return mMsg.message == WM_SYSKEYDOWN || mMsg.message == WM_SYSKEYUP;
+  }
+  bool IsCharOrSysCharMessage(const MSG& aMSG) const {
+    return IsCharOrSysCharMessage(aMSG.message);
+  }
+  bool IsCharOrSysCharMessage(UINT aMessage) const {
+    return (aMessage == WM_CHAR || aMessage == WM_SYSCHAR);
+  }
+  bool IsCharMessage(const MSG& aMSG) const {
+    return IsCharMessage(aMSG.message);
+  }
+  bool IsCharMessage(UINT aMessage) const {
+    return (IsCharOrSysCharMessage(aMessage) || IsDeadCharMessage(aMessage));
+  }
+  bool IsDeadCharMessage(const MSG& aMSG) const {
+    return IsDeadCharMessage(aMSG.message);
+  }
+  bool IsDeadCharMessage(UINT aMessage) const {
+    return (aMessage == WM_DEADCHAR || aMessage == WM_SYSDEADCHAR);
+  }
+  bool IsSysCharMessage(const MSG& aMSG) const {
+    return IsSysCharMessage(aMSG.message);
+  }
+  bool IsSysCharMessage(UINT aMessage) const {
+    return (aMessage == WM_SYSCHAR || aMessage == WM_SYSDEADCHAR);
+  }
+  bool MayBeSameCharMessage(const MSG& aCharMsg1, const MSG& aCharMsg2) const;
+  bool IsSamePhysicalKeyMessage(const MSG& aKeyOrCharMsg1,
+                                const MSG& aKeyOrCharMsg2) const;
+  bool IsFollowedByPrintableCharMessage() const;
+  bool IsFollowedByPrintableCharOrSysCharMessage() const;
+  bool IsFollowedByDeadCharMessage() const;
+  bool IsPrintableCharMessage(const MSG& aMSG) const {
+    return aMSG.message == WM_CHAR &&
+           !IsControlChar(static_cast<char16_t>(aMSG.wParam));
+  }
+  bool IsEnterKeyPressCharMessage(const MSG& aMSG) const {
+    return aMSG.message == WM_CHAR && aMSG.wParam == '\r';
+  }
+  bool IsPrintableCharOrSysCharMessage(const MSG& aMSG) const {
+    return IsCharOrSysCharMessage(aMSG) &&
+           !IsControlChar(static_cast<char16_t>(aMSG.wParam));
+  }
+  bool IsControlCharMessage(const MSG& aMSG) const {
+    return IsCharMessage(aMSG.message) &&
+           IsControlChar(static_cast<char16_t>(aMSG.wParam));
+  }
+
+  /**
+   * IsReservedBySystem() returns true if the key combination is reserved by
+   * the system.  Even if it's consumed by web apps, the message should be
+   * sent to next wndproc.
+   */
+  bool IsReservedBySystem() const;
+
+  /**
+   * GetFollowingCharMessage() returns following char message of handling
+   * keydown event.  If the message is found, this method returns true.
+   * Otherwise, returns false.
+   *
+   * WARNING: Even if this returns true, aCharMsg may be WM_NULL or its
+   *          hwnd may be different window.
+   */
+  bool GetFollowingCharMessage(MSG& aCharMsg);
+
+  /**
+   * Wraps MapVirtualKeyEx() with MAPVK_VSC_TO_VK.
+   */
+  uint8_t ComputeVirtualKeyCodeFromScanCode() const;
+
+  /**
+   * Wraps MapVirtualKeyEx() with MAPVK_VSC_TO_VK_EX.
+   */
+  uint8_t ComputeVirtualKeyCodeFromScanCodeEx() const;
+
+  /**
+   * Wraps MapVirtualKeyEx() with MAPVK_VK_TO_VSC_EX or MAPVK_VK_TO_VSC.
+   */
+  uint16_t ComputeScanCodeExFromVirtualKeyCode(UINT aVirtualKeyCode) const;
+
+  /**
+   * Wraps MapVirtualKeyEx() with MAPVK_VSC_TO_VK and MAPVK_VK_TO_CHAR.
+   */
+  char16_t ComputeUnicharFromScanCode() const;
+
+  /**
+   * Initializes the aKeyEvent with the information stored in the instance.
+   */
+  nsEventStatus InitKeyEvent(WidgetKeyboardEvent& aKeyEvent,
+                             const ModifierKeyState& aModKeyState) const;
+  nsEventStatus InitKeyEvent(WidgetKeyboardEvent& aKeyEvent) const;
+
+  /**
+   * Dispatches a command event for aEventCommand.
+   * Returns true if the event is consumed.  Otherwise, false.
+   */
+  bool DispatchCommandEvent(uint32_t aEventCommand) const;
+
+  /**
+   * DispatchKeyPressEventsWithRetrievedCharMessages() dispatches keypress
+   * event(s) with retrieved char messages.
+   */
+  bool DispatchKeyPressEventsWithRetrievedCharMessages() const;
+
+  /**
+   * DispatchKeyPressEventsWithoutCharMessage() dispatches keypress event(s)
+   * without char messages.  So, this should be used only when there are no
+   * following char messages.
+   */
+  bool DispatchKeyPressEventsWithoutCharMessage() const;
+
+  /**
+   * Checkes whether the key event down message is handled without following
+   * WM_CHAR messages.  For example, if following WM_CHAR message indicates
+   * control character input, the WM_CHAR message is unclear whether it's
+   * caused by a printable key with Ctrl or just a function key such as Enter
+   * or Backspace.
+   */
+  bool NeedsToHandleWithoutFollowingCharMessages() const;
+
+  /**
+   * ComputeInputtingStringWithKeyboardLayout() computes string to be inputted
+   * with the key and the modifier state, without shift state and with shift
+   * state.
+   */
+  void ComputeInputtingStringWithKeyboardLayout();
+
+  /**
+   * IsFocusedWindowChanged() returns true if focused window is changed
+   * after the instance is created.
+   */
+  bool IsFocusedWindowChanged() const {
+    return mFocusedWndBeforeDispatch != ::GetFocus();
+  }
+
+  /**
+   * Handles WM_CHAR message or WM_SYSCHAR message.  The instance must be
+   * initialized with WM_KEYDOWN, WM_SYSKEYDOWN or them.
+   * Returns true if dispatched keypress event is consumed.  Otherwise, false.
+   */
+  bool HandleCharMessage(const MSG& aCharMsg,
+                         bool* aEventDispatched = nullptr) const;
+
+  // Calls of PeekMessage() from NativeKey might cause nested message handling
+  // due to (perhaps) odd API hook.  NativeKey should do nothing if given
+  // message is tried to be retrieved by another instance.
+
+  /**
+   * sLatestInstacne is a pointer to the newest instance of NativeKey which is
+   * handling a key or char message(s).
+   */
+  static NativeKey* sLatestInstance;
+
+  static const MSG sEmptyMSG;
+
+  static MSG sLastKeyOrCharMSG;
+
+  static MSG sLastKeyMSG;
+
+  // Set to non-zero if we receive a WM_KEYDOWN message which introduces only
+  // a high surrogate.  Then, it'll be cleared when next keydown or char message
+  // is received.
+  static char16_t sPendingHighSurrogate;
+
+  static bool IsEmptyMSG(const MSG& aMSG) {
+    return !memcmp(&aMSG, &sEmptyMSG, sizeof(MSG));
+  }
+
+  bool IsAnotherInstanceRemovingCharMessage() const {
+    return mLastInstance && !IsEmptyMSG(mLastInstance->mRemovingMsg);
+  }
+
+ public:
+  /**
+   * Returns last key or char MSG.  If no MSG has been received yet, the result
+   * is empty MSG (i.e., .message is WM_NULL).
+   */
+  static const MSG& LastKeyOrCharMSG() { return sLastKeyOrCharMSG; }
+};
+
+class KeyboardLayout {
+ public:
+  static KeyboardLayout* GetInstance();
+  static void Shutdown();
+
+  /**
+   * GetLayout() returns a keyboard layout which has already been loaded in the
+   * singleton instance or active keyboard layout.
+   */
+  static HKL GetLayout() {
+    if (!sInstance || sInstance->mIsPendingToRestoreKeyboardLayout) {
+      return ::GetKeyboardLayout(0);
+    }
+    return sInstance->mKeyboardLayout;
+  }
+
+  /**
+   * GetLoadedLayout() returns a keyboard layout which was loaded in the
+   * singleton instance.  This may be different from the active keyboard layout
+   * on the system if we override the keyboard layout for synthesizing native
+   * key events for tests.
+   */
+  HKL GetLoadedLayout() { return mKeyboardLayout; }
+
+  /**
+   * GetLoadedLayoutName() returns the name of the loaded keyboard layout in the
+   * singleton instance.
+   */
+  nsCString GetLoadedLayoutName() {
+    return KeyboardLayout::GetLayoutName(mKeyboardLayout);
+  }
+
+  static void NotifyIdleServiceOfUserActivity();
+
+  static bool IsPrintableCharKey(uint8_t aVirtualKey);
+
+  /**
+   * HasAltGr() returns true if the keyboard layout's AltRight key is AltGr
+   * key.
+   */
+  bool HasAltGr() const { return mHasAltGr; }
+
+  /**
+   * IsDeadKey() returns true if aVirtualKey is a dead key with aModKeyState.
+   * This method isn't stateful.
+   */
+  bool IsDeadKey(uint8_t aVirtualKey,
+                 const ModifierKeyState& aModKeyState) const;
+  bool IsDeadKey(const NativeKey& aNativeKey) const {
+    return IsDeadKey(aNativeKey.GenericVirtualKeyCode(),
+                     aNativeKey.ModifierKeyStateRef());
+  }
+
+  /**
+   * IsInDeadKeySequence() returns true when it's in a dead key sequence.
+   * It starts when a dead key is down and ends when another key down causes
+   * inactivating the dead key state.
+   */
+  bool IsInDeadKeySequence() const { return !mActiveDeadKeys.IsEmpty(); }
+
+  /**
+   * IsSysKey() returns true if aVirtualKey with aModKeyState causes WM_SYSKEY*
+   * or WM_SYS*CHAR messages.
+   */
+  bool IsSysKey(uint8_t aVirtualKey,
+                const ModifierKeyState& aModKeyState) const;
+  bool IsSysKey(const NativeKey& aNativeKey) const {
+    return IsSysKey(aNativeKey.GenericVirtualKeyCode(),
+                    aNativeKey.ModifierKeyStateRef());
+  }
+
+  /**
+   * GetUniCharsAndModifiers() returns characters which are inputted by
+   * aVirtualKey with aModKeyState.  This method isn't stateful.
+   * Note that if the combination causes text input, the result's Ctrl and
+   * Alt key state are never active.
+   */
+  UniCharsAndModifiers GetUniCharsAndModifiers(
+      uint8_t aVirtualKey, const ModifierKeyState& aModKeyState) const {
+    VirtualKey::ShiftState shiftState =
+        VirtualKey::ModifierKeyStateToShiftState(aModKeyState);
+    return GetUniCharsAndModifiers(aVirtualKey, shiftState);
+  }
+  UniCharsAndModifiers GetUniCharsAndModifiers(
+      const NativeKey& aNativeKey) const {
+    return GetUniCharsAndModifiers(aNativeKey.GenericVirtualKeyCode(),
+                                   aNativeKey.GetShiftState());
+  }
+
+  /**
+   * OnLayoutChange() must be called before the first keydown message is
+   * received.  LoadLayout() changes the keyboard state, that causes breaking
+   * dead key state.  Therefore, we need to load the layout before the first
+   * keydown message.
+   */
+  void OnLayoutChange(HKL aKeyboardLayout) {
+    MOZ_ASSERT(!mIsOverridden);
+    LoadLayout(aKeyboardLayout);
+  }
+
+  /**
+   * OverrideLayout() loads the specified keyboard layout.
+   */
+  void OverrideLayout(HKL aLayout) {
+    mIsOverridden = true;
+    LoadLayout(aLayout);
+  }
+
+  /**
+   * RestoreLayout() loads the current keyboard layout of the thread.
+   */
+  void RestoreLayout() {
+    mIsOverridden = false;
+    mIsPendingToRestoreKeyboardLayout = true;
+  }
+
+  uint32_t ConvertNativeKeyCodeToDOMKeyCode(UINT aNativeKeyCode) const;
+
+  /**
+   * ConvertNativeKeyCodeToKeyNameIndex() returns KeyNameIndex value for
+   * non-printable keys (except some special keys like space key).
+   */
+  KeyNameIndex ConvertNativeKeyCodeToKeyNameIndex(uint8_t aVirtualKey) const;
+
+  /**
+   * ConvertScanCodeToCodeNameIndex() returns CodeNameIndex value for
+   * the given scan code.  aScanCode can be over 0xE000 since this method
+   * doesn't use Windows API.
+   */
+  static CodeNameIndex ConvertScanCodeToCodeNameIndex(UINT aScanCode);
+
+  /**
+   * This wraps MapVirtualKeyEx() API with MAPVK_VK_TO_VSC.
+   */
+  WORD ComputeScanCodeForVirtualKeyCode(uint8_t aVirtualKeyCode) const;
+
+  /**
+   * Implementation of nsIWidget::SynthesizeNativeKeyEvent().
+   */
+  nsresult SynthesizeNativeKeyEvent(nsWindow* aWidget,
+                                    int32_t aNativeKeyboardLayout,
+                                    int32_t aNativeKeyCode,
+                                    uint32_t aModifierFlags,
+                                    const nsAString& aCharacters,
+                                    const nsAString& aUnmodifiedCharacters);
+
+ private:
+  KeyboardLayout();
+  ~KeyboardLayout();
+
+  static KeyboardLayout* sInstance;
+  static StaticRefPtr<nsIUserIdleServiceInternal> sIdleService;
+
+  struct DeadKeyTableListEntry {
+    DeadKeyTableListEntry* next;
+    uint8_t data[1];
+  };
+
+  HKL mKeyboardLayout = nullptr;
+
+  VirtualKey mVirtualKeys[NS_NUM_OF_KEYS] = {};
+  DeadKeyTableListEntry* mDeadKeyTableListHead = nullptr;
+  // When mActiveDeadKeys is empty, it's not in dead key sequence.
+  // Otherwise, it contains virtual keycodes which are pressed in current
+  // dead key sequence.
+  nsTArray<uint8_t> mActiveDeadKeys;
+  // mDeadKeyShiftStates is always same length as mActiveDeadKeys.
+  // This stores shift states at pressing each dead key stored in
+  // mActiveDeadKeys.
+  nsTArray<VirtualKey::ShiftState> mDeadKeyShiftStates;
+
+  bool mIsOverridden = false;
+  bool mIsPendingToRestoreKeyboardLayout = false;
+  bool mHasAltGr = false;
+
+  static inline int32_t GetKeyIndex(uint8_t aVirtualKey);
+  static bool AddDeadKeyEntry(char16_t aBaseChar, char16_t aCompositeChar,
+                              nsTArray<DeadKeyEntry>& aDeadKeyArray);
+  bool EnsureDeadKeyActive(bool aIsActive, uint8_t aDeadKey,
+                           const PBYTE aDeadKeyKbdState);
+  uint32_t GetDeadKeyCombinations(uint8_t aDeadKey,
+                                  const PBYTE aDeadKeyKbdState,
+                                  uint16_t aShiftStatesWithBaseChars,
+                                  nsTArray<DeadKeyEntry>& aDeadKeyArray);
+  /**
+   * Activates or deactivates dead key state.
+   */
+  void ActivateDeadKeyState(const NativeKey& aNativeKey);
+  void DeactivateDeadKeyState();
+
+  const DeadKeyTable* AddDeadKeyTable(const DeadKeyEntry* aDeadKeyArray,
+                                      uint32_t aEntries);
+  void ReleaseDeadKeyTables();
+
+  /**
+   * Loads the specified keyboard layout. This method always clear the dead key
+   * state.
+   */
+  void LoadLayout(HKL aLayout);
+
+  /**
+   * Gets the keyboard layout name of aLayout.  Be careful, this may be too
+   * slow to call at handling user input.
+   */
+  static nsCString GetLayoutName(HKL aLayout);
+
+  /**
+   * InitNativeKey() must be called when actually widget receives WM_KEYDOWN or
+   * WM_KEYUP.  This method is stateful.  This saves current dead key state at
+   * WM_KEYDOWN.  Additionally, computes current inputted character(s) and set
+   * them to the aNativeKey.
+   */
+  void InitNativeKey(NativeKey& aNativeKey);
+
+  /**
+   * MaybeInitNativeKeyAsDeadKey() initializes aNativeKey only when aNativeKey
+   * is a dead key's event.
+   * When it's not in a dead key sequence, this activates the dead key state.
+   * When it's in a dead key sequence, this initializes aNativeKey with a
+   * composite character or a preceding dead char and a dead char which should
+   * be caused by aNativeKey.
+   * Returns true when this initializes aNativeKey.  Otherwise, false.
+   */
+  bool MaybeInitNativeKeyAsDeadKey(NativeKey& aNativeKey);
+
+  /**
+   * MaybeInitNativeKeyWithCompositeChar() may initialize aNativeKey with
+   * proper composite character when dead key produces a composite character.
+   * Otherwise, just returns false.
+   */
+  bool MaybeInitNativeKeyWithCompositeChar(NativeKey& aNativeKey);
+
+  /**
+   * See the comment of GetUniCharsAndModifiers() below.
+   */
+  UniCharsAndModifiers GetUniCharsAndModifiers(
+      uint8_t aVirtualKey, VirtualKey::ShiftState aShiftState) const;
+
+  /**
+   * GetDeadUniCharsAndModifiers() returns dead chars which are stored in
+   * current dead key sequence.  So, this is stateful.
+   */
+  UniCharsAndModifiers GetDeadUniCharsAndModifiers() const;
+
+  /**
+   * GetCompositeChar() returns a composite character with dead character
+   * caused by mActiveDeadKeys, mDeadKeyShiftStates and a base character
+   * (aBaseChar).
+   * If the combination of the dead character and the base character doesn't
+   * cause a composite character, this returns 0.
+   */
+  char16_t GetCompositeChar(char16_t aBaseChar) const;
+
+  // NativeKey class should access InitNativeKey() directly, but it shouldn't
+  // be available outside of NativeKey.  So, let's make NativeKey a friend
+  // class of this.
+  friend class NativeKey;
+};
+
+class RedirectedKeyDownMessageManager {
+ public:
+  /*
+   * If a window receives WM_KEYDOWN message or WM_SYSKEYDOWM message which is
+   * a redirected message, NativeKey::DispatchKeyDownAndKeyPressEvent()
+   * prevents to dispatch eKeyDown event because it has been dispatched
+   * before the message was redirected.  However, in some cases, WM_*KEYDOWN
+   * message handler may not handle actually.  Then, the message handler needs
+   * to forget the redirected message and remove WM_CHAR message or WM_SYSCHAR
+   * message for the redirected keydown message.  AutoFlusher class is a helper
+   * class for doing it.  This must be created in the stack.
+   */
+  class MOZ_STACK_CLASS AutoFlusher final {
+   public:
+    AutoFlusher(nsWindow* aWidget, const MSG& aMsg)
+        : mCancel(!RedirectedKeyDownMessageManager::IsRedirectedMessage(aMsg)),
+          mWidget(aWidget),
+          mMsg(aMsg) {}
+
+    ~AutoFlusher() {
+      if (mCancel) {
+        return;
+      }
+      // Prevent unnecessary keypress event
+      if (!mWidget->Destroyed()) {
+        RedirectedKeyDownMessageManager::RemoveNextCharMessage(mMsg.hwnd);
+      }
+      // Foreget the redirected message
+      RedirectedKeyDownMessageManager::Forget();
+    }
+
+    void Cancel() { mCancel = true; }
+
+   private:
+    bool mCancel;
+    RefPtr<nsWindow> mWidget;
+    const MSG& mMsg;
+  };
+
+  static void WillRedirect(const MSG& aMsg, bool aDefualtPrevented) {
+    sRedirectedKeyDownMsg = aMsg;
+    sDefaultPreventedOfRedirectedMsg = aDefualtPrevented;
+  }
+
+  static void Forget() { sRedirectedKeyDownMsg.message = WM_NULL; }
+
+  static void PreventDefault() { sDefaultPreventedOfRedirectedMsg = true; }
+  static bool DefaultPrevented() { return sDefaultPreventedOfRedirectedMsg; }
+
+  static bool IsRedirectedMessage(const MSG& aMsg);
+
+  /**
+   * RemoveNextCharMessage() should be called by WM_KEYDOWN or WM_SYSKEYDOWM
+   * message handler.  If there is no WM_(SYS)CHAR message for it, this
+   * method does nothing.
+   * NOTE: WM_(SYS)CHAR message is posted by TranslateMessage() API which is
+   * called in message loop.  So, WM_(SYS)KEYDOWN message should have
+   * WM_(SYS)CHAR message in the queue if the keydown event causes character
+   * input.
+   */
+  static void RemoveNextCharMessage(HWND aWnd);
+
+ private:
+  // sRedirectedKeyDownMsg is WM_KEYDOWN message or WM_SYSKEYDOWN message which
+  // is reirected with SendInput() API by
+  // widget::NativeKey::DispatchKeyDownAndKeyPressEvent()
+  static MSG sRedirectedKeyDownMsg;
+  static bool sDefaultPreventedOfRedirectedMsg;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/windows/LSPAnnotator.cpp b/widget/windows/LSPAnnotator.cpp
new file mode 100644
index 0000000000..ab3a768d66
--- /dev/null
+++ b/widget/windows/LSPAnnotator.cpp
@@ -0,0 +1,135 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * LSPs are evil little bits of code that are allowed to inject into our
+ * networking stack by Windows.  Once they have wormed into our process
+ * they gnaw at our innards until we crash.  Here we force the buggers
+ * into the light by recording them in our crash information.
+ * We do the enumeration on a thread because I'm concerned about startup perf
+ * on machines with several LSPs.
+ */
+
+#include "nsICrashReporter.h"
+#include "nsISupportsImpl.h"
+#include "nsServiceManagerUtils.h"
+#include "nsThreadUtils.h"
+#include "nsQueryObject.h"
+#include "nsWindowsHelpers.h"
+#include <windows.h>
+#include <rpc.h>
+#include <ws2spi.h>
+
+namespace mozilla {
+namespace crashreporter {
+
+class LSPAnnotationGatherer : public Runnable {
+  ~LSPAnnotationGatherer() {}
+
+ public:
+  LSPAnnotationGatherer() : Runnable("crashreporter::LSPAnnotationGatherer") {}
+  NS_DECL_NSIRUNNABLE
+
+  void Annotate();
+  nsCString mString;
+};
+
+void LSPAnnotationGatherer::Annotate() {
+  nsCOMPtr<nsICrashReporter> cr =
+      do_GetService("@mozilla.org/toolkit/crash-reporter;1");
+  bool enabled;
+  if (cr && NS_SUCCEEDED(cr->GetCrashReporterEnabled(&enabled)) && enabled) {
+    cr->AnnotateCrashReport("Winsock_LSP"_ns, mString);
+  }
+}
+
+NS_IMETHODIMP
+LSPAnnotationGatherer::Run() {
+  DWORD size = 0;
+  int err;
+  // Get the size of the buffer we need
+  if (SOCKET_ERROR != WSCEnumProtocols(nullptr, nullptr, &size, &err) ||
+      err != WSAENOBUFS) {
+    // Er, what?
+    MOZ_ASSERT_UNREACHABLE(
+        "WSCEnumProtocols succeeded when it should have "
+        "failed");
+    return NS_ERROR_FAILURE;
+  }
+
+  auto byteArray = MakeUnique<char[]>(size);
+  WSAPROTOCOL_INFOW* providers =
+      reinterpret_cast<WSAPROTOCOL_INFOW*>(byteArray.get());
+
+  int n = WSCEnumProtocols(nullptr, providers, &size, &err);
+  if (n == SOCKET_ERROR) {
+    // Lame. We provided the right size buffer; we'll just give up now.
+    NS_WARNING("Could not get LSP list");
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCString str;
+  for (int i = 0; i < n; i++) {
+    AppendUTF16toUTF8(nsDependentString(providers[i].szProtocol), str);
+    str.AppendLiteral(" : ");
+    str.AppendInt(providers[i].iVersion);
+    str.AppendLiteral(" : ");
+    str.AppendInt(providers[i].iAddressFamily);
+    str.AppendLiteral(" : ");
+    str.AppendInt(providers[i].iSocketType);
+    str.AppendLiteral(" : ");
+    str.AppendInt(providers[i].iProtocol);
+    str.AppendLiteral(" : ");
+    str.AppendPrintf("0x%lx", providers[i].dwServiceFlags1);
+    str.AppendLiteral(" : ");
+    str.AppendPrintf("0x%lx", providers[i].dwProviderFlags);
+    str.AppendLiteral(" : ");
+
+    wchar_t path[MAX_PATH];
+    int pathLen = MAX_PATH;
+    if (!WSCGetProviderPath(&providers[i].ProviderId, path, &pathLen, &err)) {
+      AppendUTF16toUTF8(nsDependentString(path), str);
+    }
+
+    str.AppendLiteral(" : ");
+    // Call WSCGetProviderInfo to obtain the category flags for this provider.
+    // When present, these flags inform Windows as to which order to chain the
+    // providers.
+    DWORD categoryInfo;
+    size_t categoryInfoSize = sizeof(categoryInfo);
+    if (!WSCGetProviderInfo(&providers[i].ProviderId, ProviderInfoLspCategories,
+                            (PBYTE)&categoryInfo, &categoryInfoSize, 0, &err)) {
+      str.AppendPrintf("0x%lx", categoryInfo);
+    }
+
+    str.AppendLiteral(" : ");
+    if (providers[i].ProtocolChain.ChainLen <= BASE_PROTOCOL) {
+      // If we're dealing with a catalog entry that identifies an individual
+      // base or layer provider, log its provider GUID.
+      RPC_CSTR provIdStr = nullptr;
+      if (UuidToStringA(&providers[i].ProviderId, &provIdStr) == RPC_S_OK) {
+        str.Append(reinterpret_cast<char*>(provIdStr));
+        RpcStringFreeA(&provIdStr);
+      }
+    }
+
+    if (i + 1 != n) {
+      str.AppendLiteral(" \n ");
+    }
+  }
+
+  mString = str;
+  NS_DispatchToMainThread(
+      NewRunnableMethod("crashreporter::LSPAnnotationGatherer::Annotate", this,
+                        &LSPAnnotationGatherer::Annotate));
+  return NS_OK;
+}
+
+void LSPAnnotate() {
+  nsCOMPtr<nsIRunnable> runnable(new LSPAnnotationGatherer());
+  NS_DispatchBackgroundTask(runnable.forget());
+}
+
+}  // namespace crashreporter
+}  // namespace mozilla
diff --git a/widget/windows/LegacyJumpListBuilder.cpp b/widget/windows/LegacyJumpListBuilder.cpp
new file mode 100644
index 0000000000..fbfe10f64b
--- /dev/null
+++ b/widget/windows/LegacyJumpListBuilder.cpp
@@ -0,0 +1,647 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LegacyJumpListBuilder.h"
+
+#include "nsError.h"
+#include "nsCOMPtr.h"
+#include "nsServiceManagerUtils.h"
+#include "nsString.h"
+#include "nsArrayUtils.h"
+#include "nsWidgetsCID.h"
+#include "WinTaskbar.h"
+#include "nsDirectoryServiceUtils.h"
+#include "mozilla/Preferences.h"
+#include "nsStringStream.h"
+#include "nsThreadUtils.h"
+#include "mozilla/LazyIdleThread.h"
+#include "nsIObserverService.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/Unused.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/mscom/ApartmentRegion.h"
+#include "mozilla/mscom/EnsureMTA.h"
+
+#include <shellapi.h>
+#include "WinUtils.h"
+
+using mozilla::dom::Promise;
+
+// The amount of time, in milliseconds, that our IO thread will stay alive after
+// the last event it processes.
+#define DEFAULT_THREAD_TIMEOUT_MS 30000
+
+namespace mozilla {
+namespace widget {
+
+// defined in WinTaskbar.cpp
+extern const wchar_t* gMozillaJumpListIDGeneric;
+
+Atomic<bool> LegacyJumpListBuilder::sBuildingList(false);
+const char kPrefTaskbarEnabled[] = "browser.taskbar.lists.enabled";
+
+NS_IMPL_ISUPPORTS(LegacyJumpListBuilder, nsILegacyJumpListBuilder, nsIObserver)
+#define TOPIC_PROFILE_BEFORE_CHANGE "profile-before-change"
+#define TOPIC_CLEAR_PRIVATE_DATA "clear-private-data"
+
+namespace detail {
+
+class DoneCommitListBuildCallback final : public nsIRunnable {
+  NS_DECL_THREADSAFE_ISUPPORTS
+
+ public:
+  DoneCommitListBuildCallback(nsILegacyJumpListCommittedCallback* aCallback,
+                              LegacyJumpListBuilder* aBuilder)
+      : mCallback(aCallback), mBuilder(aBuilder), mResult(false) {}
+
+  NS_IMETHOD Run() override {
+    MOZ_ASSERT(NS_IsMainThread());
+    if (mCallback) {
+      Unused << mCallback->Done(mResult);
+    }
+    // Ensure we are releasing on the main thread.
+    Destroy();
+    return NS_OK;
+  }
+
+  void SetResult(bool aResult) { mResult = aResult; }
+
+ private:
+  ~DoneCommitListBuildCallback() {
+    // Destructor does not always call on the main thread.
+    MOZ_ASSERT(!mCallback);
+    MOZ_ASSERT(!mBuilder);
+  }
+
+  void Destroy() {
+    MOZ_ASSERT(NS_IsMainThread());
+    mCallback = nullptr;
+    mBuilder = nullptr;
+  }
+
+  // These two references MUST be released on the main thread.
+  RefPtr<nsILegacyJumpListCommittedCallback> mCallback;
+  RefPtr<LegacyJumpListBuilder> mBuilder;
+  bool mResult;
+};
+
+NS_IMPL_ISUPPORTS(DoneCommitListBuildCallback, nsIRunnable);
+
+}  // namespace detail
+
+LegacyJumpListBuilder::LegacyJumpListBuilder()
+    : mMaxItems(0),
+      mHasCommit(false),
+      mMonitor("LegacyJumpListBuilderMonitor") {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // Instantiate mJumpListMgr in the multithreaded apartment so that proxied
+  // calls on that object do not need to interact with the main thread's message
+  // pump.
+  mscom::EnsureMTA([&]() {
+    RefPtr<ICustomDestinationList> jumpListMgr;
+    HRESULT hr = ::CoCreateInstance(
+        CLSID_DestinationList, nullptr, CLSCTX_INPROC_SERVER,
+        IID_ICustomDestinationList, getter_AddRefs(jumpListMgr));
+    if (FAILED(hr)) {
+      return;
+    }
+
+    ReentrantMonitorAutoEnter lock(mMonitor);
+    // Since we are accessing mJumpListMgr across different threads
+    // (ie, different apartments), mJumpListMgr must be an agile reference.
+    mJumpListMgr = mscom::AgileReference(jumpListMgr);
+  });
+
+  if (!mJumpListMgr) {
+    return;
+  }
+
+  // Make a lazy thread for any IO
+  mIOThread = new LazyIdleThread(DEFAULT_THREAD_TIMEOUT_MS, "Jump List",
+                                 LazyIdleThread::ManualShutdown);
+  Preferences::AddStrongObserver(this, kPrefTaskbarEnabled);
+
+  nsCOMPtr<nsIObserverService> observerService =
+      do_GetService("@mozilla.org/observer-service;1");
+  if (observerService) {
+    observerService->AddObserver(this, TOPIC_PROFILE_BEFORE_CHANGE, false);
+    observerService->AddObserver(this, TOPIC_CLEAR_PRIVATE_DATA, false);
+  }
+}
+
+LegacyJumpListBuilder::~LegacyJumpListBuilder() {
+  Preferences::RemoveObserver(this, kPrefTaskbarEnabled);
+}
+
+NS_IMETHODIMP LegacyJumpListBuilder::SetAppUserModelID(
+    const nsAString& aAppUserModelId) {
+  ReentrantMonitorAutoEnter lock(mMonitor);
+  if (!mJumpListMgr) return NS_ERROR_NOT_AVAILABLE;
+
+  RefPtr<ICustomDestinationList> jumpListMgr = mJumpListMgr.Resolve();
+  if (!jumpListMgr) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  mAppUserModelId.Assign(aAppUserModelId);
+  // MSIX packages explicitly do not support setting the appid from within
+  // the app, as it is set in the package manifest instead.
+  if (!mozilla::widget::WinUtils::HasPackageIdentity()) {
+    jumpListMgr->SetAppID(mAppUserModelId.get());
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListBuilder::GetAvailable(int16_t* aAvailable) {
+  *aAvailable = false;
+
+  ReentrantMonitorAutoEnter lock(mMonitor);
+  if (mJumpListMgr) *aAvailable = true;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListBuilder::GetIsListCommitted(bool* aCommit) {
+  *aCommit = mHasCommit;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListBuilder::GetMaxListItems(int16_t* aMaxItems) {
+  ReentrantMonitorAutoEnter lock(mMonitor);
+  if (!mJumpListMgr) return NS_ERROR_NOT_AVAILABLE;
+
+  *aMaxItems = 0;
+
+  if (sBuildingList) {
+    *aMaxItems = mMaxItems;
+    return NS_OK;
+  }
+
+  RefPtr<ICustomDestinationList> jumpListMgr = mJumpListMgr.Resolve();
+  if (!jumpListMgr) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  IObjectArray* objArray;
+  if (SUCCEEDED(jumpListMgr->BeginList(&mMaxItems, IID_PPV_ARGS(&objArray)))) {
+    *aMaxItems = mMaxItems;
+
+    if (objArray) objArray->Release();
+
+    jumpListMgr->AbortList();
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListBuilder::InitListBuild(JSContext* aCx,
+                                                   Promise** aPromise) {
+  ReentrantMonitorAutoEnter lock(mMonitor);
+  if (!mJumpListMgr) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsIGlobalObject* globalObject = xpc::CurrentNativeGlobal(aCx);
+  if (NS_WARN_IF(!globalObject)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  ErrorResult result;
+  RefPtr<Promise> promise = Promise::Create(globalObject, result);
+  if (NS_WARN_IF(result.Failed())) {
+    return result.StealNSResult();
+  }
+
+  nsCOMPtr<nsIRunnable> runnable =
+      NewRunnableMethod<StoreCopyPassByRRef<RefPtr<Promise>>>(
+          "InitListBuild", this, &LegacyJumpListBuilder::DoInitListBuild,
+          promise);
+  nsresult rv = mIOThread->Dispatch(runnable, NS_DISPATCH_NORMAL);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  promise.forget(aPromise);
+  return NS_OK;
+}
+
+void LegacyJumpListBuilder::DoInitListBuild(RefPtr<Promise>&& aPromise) {
+  // Since we're invoking COM interfaces to talk to the shell on a background
+  // thread, we need to be running inside a multithreaded apartment.
+  mscom::MTARegion mta;
+  MOZ_ASSERT(mta.IsValid());
+
+  ReentrantMonitorAutoEnter lock(mMonitor);
+  MOZ_ASSERT(mJumpListMgr);
+
+  if (sBuildingList) {
+    AbortListBuild();
+  }
+
+  HRESULT hr = E_UNEXPECTED;
+  auto errorHandler = MakeScopeExit([&aPromise, &hr]() {
+    if (SUCCEEDED(hr)) {
+      return;
+    }
+
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "InitListBuildReject", [promise = std::move(aPromise)]() {
+          promise->MaybeReject(NS_ERROR_FAILURE);
+        }));
+  });
+
+  RefPtr<ICustomDestinationList> jumpListMgr = mJumpListMgr.Resolve();
+  if (!jumpListMgr) {
+    return;
+  }
+
+  nsTArray<nsString> urisToRemove;
+  RefPtr<IObjectArray> objArray;
+  hr = jumpListMgr->BeginList(
+      &mMaxItems,
+      IID_PPV_ARGS(static_cast<IObjectArray**>(getter_AddRefs(objArray))));
+  if (FAILED(hr)) {
+    return;
+  }
+
+  // The returned objArray of removed items are for manually removed items.
+  // This does not return items which are removed because they were previously
+  // part of the jump list but are no longer part of the jump list.
+  sBuildingList = true;
+  RemoveIconCacheAndGetJumplistShortcutURIs(objArray, urisToRemove);
+
+  NS_DispatchToMainThread(NS_NewRunnableFunction(
+      "InitListBuildResolve", [urisToRemove = std::move(urisToRemove),
+                               promise = std::move(aPromise)]() {
+        promise->MaybeResolve(urisToRemove);
+      }));
+}
+
+// Ensures that we have no old ICO files left in the jump list cache
+nsresult LegacyJumpListBuilder::RemoveIconCacheForAllItems() {
+  // Construct the path of our jump list cache
+  nsCOMPtr<nsIFile> jumpListCacheDir;
+  nsresult rv =
+      NS_GetSpecialDirectory("ProfLDS", getter_AddRefs(jumpListCacheDir));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = jumpListCacheDir->AppendNative(
+      nsDependentCString(mozilla::widget::FaviconHelper::kJumpListCacheDir));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIDirectoryEnumerator> entries;
+  rv = jumpListCacheDir->GetDirectoryEntries(getter_AddRefs(entries));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Loop through each directory entry and remove all ICO files found
+  do {
+    nsCOMPtr<nsIFile> currFile;
+    if (NS_FAILED(entries->GetNextFile(getter_AddRefs(currFile))) || !currFile)
+      break;
+
+    nsAutoString path;
+    if (NS_FAILED(currFile->GetPath(path))) continue;
+
+    if (StringTail(path, 4).LowerCaseEqualsASCII(".ico")) {
+      // Check if the cached ICO file exists
+      bool exists;
+      if (NS_FAILED(currFile->Exists(&exists)) || !exists) continue;
+
+      // We found an ICO file that exists, so we should remove it
+      currFile->Remove(false);
+    }
+  } while (true);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListBuilder::AddListToBuild(int16_t aCatType,
+                                                    nsIArray* items,
+                                                    const nsAString& catName,
+                                                    bool* _retval) {
+  nsresult rv;
+
+  *_retval = false;
+
+  ReentrantMonitorAutoEnter lock(mMonitor);
+  if (!mJumpListMgr) return NS_ERROR_NOT_AVAILABLE;
+
+  RefPtr<ICustomDestinationList> jumpListMgr = mJumpListMgr.Resolve();
+  if (!jumpListMgr) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  switch (aCatType) {
+    case nsILegacyJumpListBuilder::JUMPLIST_CATEGORY_TASKS: {
+      NS_ENSURE_ARG_POINTER(items);
+
+      HRESULT hr;
+      RefPtr<IObjectCollection> collection;
+      hr = CoCreateInstance(CLSID_EnumerableObjectCollection, nullptr,
+                            CLSCTX_INPROC_SERVER, IID_IObjectCollection,
+                            getter_AddRefs(collection));
+      if (FAILED(hr)) return NS_ERROR_UNEXPECTED;
+
+      // Build the list
+      uint32_t length;
+      items->GetLength(&length);
+      for (uint32_t i = 0; i < length; ++i) {
+        nsCOMPtr<nsILegacyJumpListItem> item = do_QueryElementAt(items, i);
+        if (!item) continue;
+        // Check for separators
+        if (IsSeparator(item)) {
+          RefPtr<IShellLinkW> link;
+          rv = LegacyJumpListSeparator::GetSeparator(link);
+          if (NS_FAILED(rv)) return rv;
+          collection->AddObject(link);
+          continue;
+        }
+        // These should all be ShellLinks
+        RefPtr<IShellLinkW> link;
+        rv = LegacyJumpListShortcut::GetShellLink(item, link, mIOThread);
+        if (NS_FAILED(rv)) return rv;
+        collection->AddObject(link);
+      }
+
+      // We need IObjectArray to submit
+      RefPtr<IObjectArray> pArray;
+      hr = collection->QueryInterface(IID_IObjectArray, getter_AddRefs(pArray));
+      if (FAILED(hr)) return NS_ERROR_UNEXPECTED;
+
+      // Add the tasks
+      hr = jumpListMgr->AddUserTasks(pArray);
+      if (SUCCEEDED(hr)) *_retval = true;
+      return NS_OK;
+    } break;
+    case nsILegacyJumpListBuilder::JUMPLIST_CATEGORY_RECENT: {
+      if (SUCCEEDED(jumpListMgr->AppendKnownCategory(KDC_RECENT)))
+        *_retval = true;
+      return NS_OK;
+    } break;
+    case nsILegacyJumpListBuilder::JUMPLIST_CATEGORY_FREQUENT: {
+      if (SUCCEEDED(jumpListMgr->AppendKnownCategory(KDC_FREQUENT)))
+        *_retval = true;
+      return NS_OK;
+    } break;
+    case nsILegacyJumpListBuilder::JUMPLIST_CATEGORY_CUSTOMLIST: {
+      NS_ENSURE_ARG_POINTER(items);
+
+      if (catName.IsEmpty()) return NS_ERROR_INVALID_ARG;
+
+      HRESULT hr;
+      RefPtr<IObjectCollection> collection;
+      hr = CoCreateInstance(CLSID_EnumerableObjectCollection, nullptr,
+                            CLSCTX_INPROC_SERVER, IID_IObjectCollection,
+                            getter_AddRefs(collection));
+      if (FAILED(hr)) return NS_ERROR_UNEXPECTED;
+
+      uint32_t length;
+      items->GetLength(&length);
+      for (uint32_t i = 0; i < length; ++i) {
+        nsCOMPtr<nsILegacyJumpListItem> item = do_QueryElementAt(items, i);
+        if (!item) continue;
+        int16_t type;
+        if (NS_FAILED(item->GetType(&type))) continue;
+        switch (type) {
+          case nsILegacyJumpListItem::JUMPLIST_ITEM_SEPARATOR: {
+            RefPtr<IShellLinkW> shellItem;
+            rv = LegacyJumpListSeparator::GetSeparator(shellItem);
+            if (NS_FAILED(rv)) return rv;
+            collection->AddObject(shellItem);
+          } break;
+          case nsILegacyJumpListItem::JUMPLIST_ITEM_LINK: {
+            RefPtr<IShellItem2> shellItem;
+            rv = LegacyJumpListLink::GetShellItem(item, shellItem);
+            if (NS_FAILED(rv)) return rv;
+            collection->AddObject(shellItem);
+          } break;
+          case nsILegacyJumpListItem::JUMPLIST_ITEM_SHORTCUT: {
+            RefPtr<IShellLinkW> shellItem;
+            rv = LegacyJumpListShortcut::GetShellLink(item, shellItem,
+                                                      mIOThread);
+            if (NS_FAILED(rv)) return rv;
+            collection->AddObject(shellItem);
+          } break;
+        }
+      }
+
+      // We need IObjectArray to submit
+      RefPtr<IObjectArray> pArray;
+      hr = collection->QueryInterface(IID_IObjectArray, (LPVOID*)&pArray);
+      if (FAILED(hr)) return NS_ERROR_UNEXPECTED;
+
+      // Add the tasks
+      hr = jumpListMgr->AppendCategory(
+          reinterpret_cast<const wchar_t*>(catName.BeginReading()), pArray);
+      if (SUCCEEDED(hr)) *_retval = true;
+
+      // Get rid of the old icons
+      nsCOMPtr<nsIRunnable> event =
+          new mozilla::widget::AsyncDeleteAllFaviconsFromDisk(true);
+      mIOThread->Dispatch(event, NS_DISPATCH_NORMAL);
+
+      return NS_OK;
+    } break;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListBuilder::AbortListBuild() {
+  ReentrantMonitorAutoEnter lock(mMonitor);
+  if (!mJumpListMgr) return NS_ERROR_NOT_AVAILABLE;
+
+  RefPtr<ICustomDestinationList> jumpListMgr = mJumpListMgr.Resolve();
+  if (!jumpListMgr) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  jumpListMgr->AbortList();
+  sBuildingList = false;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListBuilder::CommitListBuild(
+    nsILegacyJumpListCommittedCallback* aCallback) {
+  ReentrantMonitorAutoEnter lock(mMonitor);
+  if (!mJumpListMgr) return NS_ERROR_NOT_AVAILABLE;
+
+  // Also holds a strong reference to this to prevent use-after-free.
+  RefPtr<detail::DoneCommitListBuildCallback> callback =
+      new detail::DoneCommitListBuildCallback(aCallback, this);
+
+  // The builder has a strong reference in the callback already, so we do not
+  // need to do it for this runnable again.
+  RefPtr<nsIRunnable> event =
+      NewNonOwningRunnableMethod<RefPtr<detail::DoneCommitListBuildCallback>>(
+          "LegacyJumpListBuilder::DoCommitListBuild", this,
+          &LegacyJumpListBuilder::DoCommitListBuild, std::move(callback));
+  Unused << mIOThread->Dispatch(event, NS_DISPATCH_NORMAL);
+
+  return NS_OK;
+}
+
+void LegacyJumpListBuilder::DoCommitListBuild(
+    RefPtr<detail::DoneCommitListBuildCallback> aCallback) {
+  // Since we're invoking COM interfaces to talk to the shell on a background
+  // thread, we need to be running inside a multithreaded apartment.
+  mscom::MTARegion mta;
+  MOZ_ASSERT(mta.IsValid());
+
+  ReentrantMonitorAutoEnter lock(mMonitor);
+  MOZ_ASSERT(mJumpListMgr);
+  MOZ_ASSERT(aCallback);
+
+  HRESULT hr = E_UNEXPECTED;
+  auto onExit = MakeScopeExit([&hr, &aCallback]() {
+    // XXX We might want some specific error data here.
+    aCallback->SetResult(SUCCEEDED(hr));
+    Unused << NS_DispatchToMainThread(aCallback);
+  });
+
+  RefPtr<ICustomDestinationList> jumpListMgr = mJumpListMgr.Resolve();
+  if (!jumpListMgr) {
+    return;
+  }
+
+  hr = jumpListMgr->CommitList();
+  sBuildingList = false;
+
+  if (SUCCEEDED(hr)) {
+    mHasCommit = true;
+  }
+}
+
+NS_IMETHODIMP LegacyJumpListBuilder::DeleteActiveList(bool* _retval) {
+  *_retval = false;
+
+  ReentrantMonitorAutoEnter lock(mMonitor);
+  if (!mJumpListMgr) return NS_ERROR_NOT_AVAILABLE;
+
+  if (sBuildingList) {
+    AbortListBuild();
+  }
+
+  RefPtr<ICustomDestinationList> jumpListMgr = mJumpListMgr.Resolve();
+  if (!jumpListMgr) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (SUCCEEDED(jumpListMgr->DeleteList(mAppUserModelId.get()))) {
+    *_retval = true;
+  }
+
+  return NS_OK;
+}
+
+/* internal */
+
+bool LegacyJumpListBuilder::IsSeparator(nsCOMPtr<nsILegacyJumpListItem>& item) {
+  int16_t type;
+  item->GetType(&type);
+  if (NS_FAILED(item->GetType(&type))) return false;
+
+  if (type == nsILegacyJumpListItem::JUMPLIST_ITEM_SEPARATOR) return true;
+  return false;
+}
+
+// RemoveIconCacheAndGetJumplistShortcutURIs - does multiple things to
+// avoid unnecessary extra XPCOM incantations. For each object in the input
+// array,  if it's an IShellLinkW, this deletes the cached icon and adds the
+// url param to a list of URLs to be removed from the places database.
+void LegacyJumpListBuilder::RemoveIconCacheAndGetJumplistShortcutURIs(
+    IObjectArray* aObjArray, nsTArray<nsString>& aURISpecs) {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  // Early return here just in case some versions of Windows don't populate this
+  if (!aObjArray) {
+    return;
+  }
+
+  uint32_t count = 0;
+  aObjArray->GetCount(&count);
+
+  for (uint32_t idx = 0; idx < count; idx++) {
+    RefPtr<IShellLinkW> pLink;
+
+    if (FAILED(aObjArray->GetAt(idx, IID_IShellLinkW,
+                                static_cast<void**>(getter_AddRefs(pLink))))) {
+      continue;
+    }
+
+    wchar_t buf[MAX_PATH];
+    HRESULT hres = pLink->GetArguments(buf, MAX_PATH);
+    if (SUCCEEDED(hres)) {
+      LPWSTR* arglist;
+      int32_t numArgs;
+
+      arglist = ::CommandLineToArgvW(buf, &numArgs);
+      if (arglist && numArgs > 0) {
+        nsString spec(arglist[0]);
+        aURISpecs.AppendElement(std::move(spec));
+        ::LocalFree(arglist);
+      }
+    }
+
+    int iconIdx = 0;
+    hres = pLink->GetIconLocation(buf, MAX_PATH, &iconIdx);
+    if (SUCCEEDED(hres)) {
+      nsDependentString spec(buf);
+      DeleteIconFromDisk(spec);
+    }
+  }
+}
+
+void LegacyJumpListBuilder::DeleteIconFromDisk(const nsAString& aPath) {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  // Check that we aren't deleting some arbitrary file that is not an icon
+  if (StringTail(aPath, 4).LowerCaseEqualsASCII(".ico")) {
+    // Construct the parent path of the passed in path
+    nsCOMPtr<nsIFile> icoFile;
+    nsresult rv = NS_NewLocalFile(aPath, true, getter_AddRefs(icoFile));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
+    }
+
+    icoFile->Remove(false);
+  }
+}
+
+NS_IMETHODIMP LegacyJumpListBuilder::Observe(nsISupports* aSubject,
+                                             const char* aTopic,
+                                             const char16_t* aData) {
+  NS_ENSURE_ARG_POINTER(aTopic);
+  if (strcmp(aTopic, TOPIC_PROFILE_BEFORE_CHANGE) == 0) {
+    nsCOMPtr<nsIObserverService> observerService =
+        do_GetService("@mozilla.org/observer-service;1");
+    if (observerService) {
+      observerService->RemoveObserver(this, TOPIC_PROFILE_BEFORE_CHANGE);
+    }
+    mIOThread->Shutdown();
+    // Clear out mJumpListMgr, as MSCOM services won't be available soon.
+    ReentrantMonitorAutoEnter lock(mMonitor);
+    mJumpListMgr = nullptr;
+  } else if (strcmp(aTopic, "nsPref:changed") == 0 &&
+             nsDependentString(aData).EqualsASCII(kPrefTaskbarEnabled)) {
+    bool enabled = Preferences::GetBool(kPrefTaskbarEnabled, true);
+    if (!enabled) {
+      nsCOMPtr<nsIRunnable> event =
+          new mozilla::widget::AsyncDeleteAllFaviconsFromDisk();
+      mIOThread->Dispatch(event, NS_DISPATCH_NORMAL);
+    }
+  } else if (strcmp(aTopic, TOPIC_CLEAR_PRIVATE_DATA) == 0) {
+    // Delete JumpListCache icons from Disk, if any.
+    nsCOMPtr<nsIRunnable> event =
+        new mozilla::widget::AsyncDeleteAllFaviconsFromDisk(false);
+    mIOThread->Dispatch(event, NS_DISPATCH_NORMAL);
+  }
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/LegacyJumpListBuilder.h b/widget/windows/LegacyJumpListBuilder.h
new file mode 100644
index 0000000000..1d96773c47
--- /dev/null
+++ b/widget/windows/LegacyJumpListBuilder.h
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __LegacyJumpListBuilder_h__
+#define __LegacyJumpListBuilder_h__
+
+#include <windows.h>
+
+// Needed for various com interfaces
+#include <shobjidl.h>
+#undef LogSeverity  // SetupAPI.h #defines this as DWORD
+
+#include "nsString.h"
+
+#include "nsILegacyJumpListBuilder.h"
+#include "nsILegacyJumpListItem.h"
+#include "LegacyJumpListItem.h"
+#include "nsIObserver.h"
+#include "nsTArray.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/LazyIdleThread.h"
+#include "mozilla/mscom/AgileReference.h"
+#include "mozilla/ReentrantMonitor.h"
+
+namespace mozilla {
+namespace widget {
+
+namespace detail {
+class DoneCommitListBuildCallback;
+}  // namespace detail
+
+class LegacyJumpListBuilder : public nsILegacyJumpListBuilder,
+                              public nsIObserver {
+  virtual ~LegacyJumpListBuilder();
+
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSILEGACYJUMPLISTBUILDER
+  NS_DECL_NSIOBSERVER
+
+  LegacyJumpListBuilder();
+
+ protected:
+  static Atomic<bool> sBuildingList;
+
+ private:
+  mscom::AgileReference<ICustomDestinationList> mJumpListMgr
+      MOZ_GUARDED_BY(mMonitor);
+  uint32_t mMaxItems MOZ_GUARDED_BY(mMonitor);
+  bool mHasCommit;
+  RefPtr<LazyIdleThread> mIOThread;
+  ReentrantMonitor mMonitor;
+  nsString mAppUserModelId;
+
+  bool IsSeparator(nsCOMPtr<nsILegacyJumpListItem>& item);
+  void RemoveIconCacheAndGetJumplistShortcutURIs(IObjectArray* aObjArray,
+                                                 nsTArray<nsString>& aURISpecs);
+  void DeleteIconFromDisk(const nsAString& aPath);
+  nsresult RemoveIconCacheForAllItems();
+  void DoCommitListBuild(RefPtr<detail::DoneCommitListBuildCallback> aCallback);
+  void DoInitListBuild(RefPtr<dom::Promise>&& aPromise);
+
+  friend class WinTaskbar;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __LegacyJumpListBuilder_h__ */
diff --git a/widget/windows/LegacyJumpListItem.cpp b/widget/windows/LegacyJumpListItem.cpp
new file mode 100644
index 0000000000..3ffddf11f9
--- /dev/null
+++ b/widget/windows/LegacyJumpListItem.cpp
@@ -0,0 +1,559 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LegacyJumpListItem.h"
+
+#include <shellapi.h>
+#include <propvarutil.h>
+#include <propkey.h>
+
+#include "nsIFile.h"
+#include "nsNetUtil.h"
+#include "nsCRT.h"
+#include "nsNetCID.h"
+#include "nsCExternalHandlerService.h"
+#include "nsComponentManagerUtils.h"
+#include "nsCycleCollectionParticipant.h"
+#include "mozilla/Preferences.h"
+#include "LegacyJumpListBuilder.h"
+#include "WinUtils.h"
+
+namespace mozilla {
+namespace widget {
+
+// ISUPPORTS Impl's
+NS_IMPL_ISUPPORTS(LegacyJumpListItem, nsILegacyJumpListItem)
+
+NS_INTERFACE_MAP_BEGIN(LegacyJumpListSeparator)
+  NS_INTERFACE_MAP_ENTRY(nsILegacyJumpListSeparator)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsILegacyJumpListItem,
+                                   LegacyJumpListItemBase)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, LegacyJumpListItemBase)
+NS_INTERFACE_MAP_END
+NS_IMPL_ADDREF(LegacyJumpListSeparator)
+NS_IMPL_RELEASE(LegacyJumpListSeparator)
+
+NS_INTERFACE_MAP_BEGIN(LegacyJumpListLink)
+  NS_INTERFACE_MAP_ENTRY(nsILegacyJumpListLink)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsILegacyJumpListItem,
+                                   LegacyJumpListItemBase)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, LegacyJumpListItemBase)
+NS_INTERFACE_MAP_END
+NS_IMPL_ADDREF(LegacyJumpListLink)
+NS_IMPL_RELEASE(LegacyJumpListLink)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(LegacyJumpListShortcut)
+  NS_INTERFACE_MAP_ENTRY(nsILegacyJumpListShortcut)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsILegacyJumpListItem,
+                                   LegacyJumpListItemBase)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsILegacyJumpListShortcut)
+NS_INTERFACE_MAP_END
+NS_IMPL_CYCLE_COLLECTING_ADDREF(LegacyJumpListShortcut)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(LegacyJumpListShortcut)
+NS_IMPL_CYCLE_COLLECTION(LegacyJumpListShortcut, mHandlerApp)
+
+NS_IMETHODIMP LegacyJumpListItemBase::GetType(int16_t* aType) {
+  NS_ENSURE_ARG_POINTER(aType);
+
+  *aType = mItemType;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListItemBase::Equals(nsILegacyJumpListItem* aItem,
+                                             bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aItem);
+
+  *aResult = false;
+
+  int16_t theType = nsILegacyJumpListItem::JUMPLIST_ITEM_EMPTY;
+  if (NS_FAILED(aItem->GetType(&theType))) return NS_OK;
+
+  // Make sure the types match.
+  if (Type() != theType) return NS_OK;
+
+  *aResult = true;
+
+  return NS_OK;
+}
+
+/* link impl. */
+
+NS_IMETHODIMP LegacyJumpListLink::GetUri(nsIURI** aURI) {
+  NS_IF_ADDREF(*aURI = mURI);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListLink::SetUri(nsIURI* aURI) {
+  mURI = aURI;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListLink::SetUriTitle(const nsAString& aUriTitle) {
+  mUriTitle.Assign(aUriTitle);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListLink::GetUriTitle(nsAString& aUriTitle) {
+  aUriTitle.Assign(mUriTitle);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListLink::Equals(nsILegacyJumpListItem* aItem,
+                                         bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aItem);
+
+  nsresult rv;
+
+  *aResult = false;
+
+  int16_t theType = nsILegacyJumpListItem::JUMPLIST_ITEM_EMPTY;
+  if (NS_FAILED(aItem->GetType(&theType))) return NS_OK;
+
+  // Make sure the types match.
+  if (Type() != theType) return NS_OK;
+
+  nsCOMPtr<nsILegacyJumpListLink> link = do_QueryInterface(aItem, &rv);
+  if (NS_FAILED(rv)) return rv;
+
+  // Check the titles
+  nsAutoString title;
+  link->GetUriTitle(title);
+  if (!mUriTitle.Equals(title)) return NS_OK;
+
+  // Call the internal object's equals() method to check.
+  nsCOMPtr<nsIURI> theUri;
+  bool equals = false;
+  if (NS_SUCCEEDED(link->GetUri(getter_AddRefs(theUri)))) {
+    if (!theUri) {
+      if (!mURI) *aResult = true;
+      return NS_OK;
+    }
+    if (NS_SUCCEEDED(theUri->Equals(mURI, &equals)) && equals) {
+      *aResult = true;
+    }
+  }
+
+  return NS_OK;
+}
+
+/* shortcut impl. */
+
+NS_IMETHODIMP LegacyJumpListShortcut::GetApp(nsILocalHandlerApp** aApp) {
+  NS_IF_ADDREF(*aApp = mHandlerApp);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListShortcut::SetApp(nsILocalHandlerApp* aApp) {
+  mHandlerApp = aApp;
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListShortcut::GetIconIndex(int32_t* aIconIndex) {
+  NS_ENSURE_ARG_POINTER(aIconIndex);
+
+  *aIconIndex = mIconIndex;
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListShortcut::SetIconIndex(int32_t aIconIndex) {
+  mIconIndex = aIconIndex;
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListShortcut::GetFaviconPageUri(
+    nsIURI** aFaviconPageURI) {
+  NS_IF_ADDREF(*aFaviconPageURI = mFaviconPageURI);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListShortcut::SetFaviconPageUri(
+    nsIURI* aFaviconPageURI) {
+  mFaviconPageURI = aFaviconPageURI;
+  return NS_OK;
+}
+
+NS_IMETHODIMP LegacyJumpListShortcut::Equals(nsILegacyJumpListItem* aItem,
+                                             bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aItem);
+
+  nsresult rv;
+
+  *aResult = false;
+
+  int16_t theType = nsILegacyJumpListItem::JUMPLIST_ITEM_EMPTY;
+  if (NS_FAILED(aItem->GetType(&theType))) return NS_OK;
+
+  // Make sure the types match.
+  if (Type() != theType) return NS_OK;
+
+  nsCOMPtr<nsILegacyJumpListShortcut> shortcut = do_QueryInterface(aItem, &rv);
+  if (NS_FAILED(rv)) return rv;
+
+  // Check the icon index
+  // int32_t idx;
+  // shortcut->GetIconIndex(&idx);
+  // if (mIconIndex != idx)
+  //  return NS_OK;
+  // No need to check the icon page URI either
+
+  // Call the internal object's equals() method to check.
+  nsCOMPtr<nsILocalHandlerApp> theApp;
+  bool equals = false;
+  if (NS_SUCCEEDED(shortcut->GetApp(getter_AddRefs(theApp)))) {
+    if (!theApp) {
+      if (!mHandlerApp) *aResult = true;
+      return NS_OK;
+    }
+    if (NS_SUCCEEDED(theApp->Equals(mHandlerApp, &equals)) && equals) {
+      *aResult = true;
+    }
+  }
+
+  return NS_OK;
+}
+
+/* internal helpers */
+
+// (static) Creates a ShellLink that encapsulate a separator.
+nsresult LegacyJumpListSeparator::GetSeparator(
+    RefPtr<IShellLinkW>& aShellLink) {
+  HRESULT hr;
+  IShellLinkW* psl;
+
+  // Create a IShellLink.
+  hr = CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER,
+                        IID_IShellLinkW, (LPVOID*)&psl);
+  if (FAILED(hr)) return NS_ERROR_UNEXPECTED;
+
+  IPropertyStore* pPropStore = nullptr;
+  hr = psl->QueryInterface(IID_IPropertyStore, (LPVOID*)&pPropStore);
+  if (FAILED(hr)) return NS_ERROR_UNEXPECTED;
+
+  PROPVARIANT pv;
+  InitPropVariantFromBoolean(TRUE, &pv);
+
+  pPropStore->SetValue(PKEY_AppUserModel_IsDestListSeparator, pv);
+  pPropStore->Commit();
+  pPropStore->Release();
+
+  PropVariantClear(&pv);
+
+  aShellLink = dont_AddRef(psl);
+
+  return NS_OK;
+}
+
+// (static) Creates a ShellLink that encapsulate a shortcut to local apps.
+nsresult LegacyJumpListShortcut::GetShellLink(
+    nsCOMPtr<nsILegacyJumpListItem>& item, RefPtr<IShellLinkW>& aShellLink,
+    RefPtr<LazyIdleThread>& aIOThread) {
+  HRESULT hr;
+  IShellLinkW* psl;
+  nsresult rv;
+
+  // Shell links:
+  // http://msdn.microsoft.com/en-us/library/bb776891(VS.85).aspx
+  // http://msdn.microsoft.com/en-us/library/bb774950(VS.85).aspx
+
+  int16_t type;
+  if (NS_FAILED(item->GetType(&type))) return NS_ERROR_INVALID_ARG;
+
+  if (type != nsILegacyJumpListItem::JUMPLIST_ITEM_SHORTCUT)
+    return NS_ERROR_INVALID_ARG;
+
+  nsCOMPtr<nsILegacyJumpListShortcut> shortcut = do_QueryInterface(item, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsILocalHandlerApp> handlerApp;
+  rv = shortcut->GetApp(getter_AddRefs(handlerApp));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Create a IShellLink
+  hr = CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER,
+                        IID_IShellLinkW, (LPVOID*)&psl);
+  if (FAILED(hr)) return NS_ERROR_UNEXPECTED;
+
+  // Retrieve the app path, title, description and optional command line args.
+  nsAutoString appPath, appTitle, appDescription, appArgs;
+  int32_t appIconIndex = 0;
+
+  // Path
+  nsCOMPtr<nsIFile> executable;
+  handlerApp->GetExecutable(getter_AddRefs(executable));
+
+  rv = executable->GetPath(appPath);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Command line parameters
+  uint32_t count = 0;
+  handlerApp->GetParameterCount(&count);
+  for (uint32_t idx = 0; idx < count; idx++) {
+    if (idx > 0) appArgs.Append(' ');
+    nsAutoString param;
+    rv = handlerApp->GetParameter(idx, param);
+    if (NS_FAILED(rv)) return rv;
+    appArgs.Append(param);
+  }
+
+  handlerApp->GetName(appTitle);
+  handlerApp->GetDetailedDescription(appDescription);
+
+  bool useUriIcon = false;   // if we want to use the URI icon
+  bool usedUriIcon = false;  // if we did use the URI icon
+  shortcut->GetIconIndex(&appIconIndex);
+
+  nsCOMPtr<nsIURI> iconUri;
+  rv = shortcut->GetFaviconPageUri(getter_AddRefs(iconUri));
+  if (NS_SUCCEEDED(rv) && iconUri) {
+    useUriIcon = true;
+  }
+
+  // Store the title of the app
+  if (appTitle.Length() > 0) {
+    IPropertyStore* pPropStore = nullptr;
+    hr = psl->QueryInterface(IID_IPropertyStore, (LPVOID*)&pPropStore);
+    if (FAILED(hr)) return NS_ERROR_UNEXPECTED;
+
+    PROPVARIANT pv;
+    InitPropVariantFromString(appTitle.get(), &pv);
+
+    pPropStore->SetValue(PKEY_Title, pv);
+    pPropStore->Commit();
+    pPropStore->Release();
+
+    PropVariantClear(&pv);
+  }
+
+  // Store the rest of the params
+  psl->SetPath(appPath.get());
+  psl->SetDescription(appDescription.get());
+  psl->SetArguments(appArgs.get());
+
+  if (useUriIcon) {
+    nsString icoFilePath;
+    rv = mozilla::widget::FaviconHelper::ObtainCachedIconFile(
+        iconUri, icoFilePath, aIOThread, false);
+    if (NS_SUCCEEDED(rv)) {
+      // Always use the first icon in the ICO file
+      // our encoded icon only has 1 resource
+      psl->SetIconLocation(icoFilePath.get(), 0);
+      usedUriIcon = true;
+    }
+  }
+
+  // We didn't use an ICO via URI so fall back to the app icon
+  if (!usedUriIcon) {
+    psl->SetIconLocation(appPath.get(), appIconIndex);
+  }
+
+  aShellLink = dont_AddRef(psl);
+
+  return NS_OK;
+}
+
+// If successful fills in the aSame parameter
+// aSame will be true if the path is in our icon cache
+static nsresult IsPathInOurIconCache(
+    nsCOMPtr<nsILegacyJumpListShortcut>& aShortcut, wchar_t* aPath,
+    bool* aSame) {
+  NS_ENSURE_ARG_POINTER(aPath);
+  NS_ENSURE_ARG_POINTER(aSame);
+
+  *aSame = false;
+
+  // Construct the path of our jump list cache
+  nsCOMPtr<nsIFile> jumpListCache;
+  nsresult rv =
+      NS_GetSpecialDirectory("ProfLDS", getter_AddRefs(jumpListCache));
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = jumpListCache->AppendNative(
+      nsDependentCString(FaviconHelper::kJumpListCacheDir));
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsAutoString jumpListCachePath;
+  rv = jumpListCache->GetPath(jumpListCachePath);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Construct the parent path of the passed in path
+  nsCOMPtr<nsIFile> passedInFile =
+      do_CreateInstance("@mozilla.org/file/local;1");
+  NS_ENSURE_TRUE(passedInFile, NS_ERROR_FAILURE);
+  nsAutoString passedInPath(aPath);
+  rv = passedInFile->InitWithPath(passedInPath);
+  nsCOMPtr<nsIFile> passedInParentFile;
+  passedInFile->GetParent(getter_AddRefs(passedInParentFile));
+  nsAutoString passedInParentPath;
+  rv = jumpListCache->GetPath(passedInParentPath);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  *aSame = jumpListCachePath.Equals(passedInParentPath);
+  return NS_OK;
+}
+
+// (static) For a given IShellLink, create and return a populated
+// nsILegacyJumpListShortcut.
+nsresult LegacyJumpListShortcut::GetJumpListShortcut(
+    IShellLinkW* pLink, nsCOMPtr<nsILegacyJumpListShortcut>& aShortcut) {
+  NS_ENSURE_ARG_POINTER(pLink);
+
+  nsresult rv;
+  HRESULT hres;
+
+  nsCOMPtr<nsILocalHandlerApp> handlerApp =
+      do_CreateInstance(NS_LOCALHANDLERAPP_CONTRACTID, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  wchar_t buf[MAX_PATH];
+
+  // Path
+  hres = pLink->GetPath(buf, MAX_PATH, nullptr, SLGP_UNCPRIORITY);
+  if (FAILED(hres)) return NS_ERROR_INVALID_ARG;
+
+  nsCOMPtr<nsIFile> file;
+  nsDependentString filepath(buf);
+  rv = NS_NewLocalFile(filepath, false, getter_AddRefs(file));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = handlerApp->SetExecutable(file);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Parameters
+  hres = pLink->GetArguments(buf, MAX_PATH);
+  if (SUCCEEDED(hres)) {
+    LPWSTR* arglist;
+    int32_t numArgs;
+    int32_t idx;
+
+    arglist = ::CommandLineToArgvW(buf, &numArgs);
+    if (arglist) {
+      for (idx = 0; idx < numArgs; idx++) {
+        // szArglist[i] is null terminated
+        nsDependentString arg(arglist[idx]);
+        handlerApp->AppendParameter(arg);
+      }
+      ::LocalFree(arglist);
+    }
+  }
+
+  rv = aShortcut->SetApp(handlerApp);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Icon index or file location
+  int iconIdx = 0;
+  hres = pLink->GetIconLocation(buf, MAX_PATH, &iconIdx);
+  if (SUCCEEDED(hres)) {
+    // XXX How do we handle converting local files to images here? Do we need
+    // to?
+    aShortcut->SetIconIndex(iconIdx);
+
+    // Obtain the local profile directory and construct the output icon file
+    // path We only set the Icon Uri if we're sure it was from our icon cache.
+    bool isInOurCache;
+    if (NS_SUCCEEDED(IsPathInOurIconCache(aShortcut, buf, &isInOurCache)) &&
+        isInOurCache) {
+      nsCOMPtr<nsIURI> iconUri;
+      nsAutoString path(buf);
+      rv = NS_NewURI(getter_AddRefs(iconUri), path);
+      if (NS_SUCCEEDED(rv)) {
+        aShortcut->SetFaviconPageUri(iconUri);
+      }
+    }
+  }
+
+  // Do we need the title and description? Probably not since handler app
+  // doesn't compare these in equals.
+
+  return NS_OK;
+}
+
+// (static) ShellItems are used to encapsulate links to things. We currently
+// only support URI links, but more support could be added, such as local file
+// and directory links.
+nsresult LegacyJumpListLink::GetShellItem(nsCOMPtr<nsILegacyJumpListItem>& item,
+                                          RefPtr<IShellItem2>& aShellItem) {
+  IShellItem2* psi = nullptr;
+  nsresult rv;
+
+  int16_t type;
+  if (NS_FAILED(item->GetType(&type))) return NS_ERROR_INVALID_ARG;
+
+  if (type != nsILegacyJumpListItem::JUMPLIST_ITEM_LINK)
+    return NS_ERROR_INVALID_ARG;
+
+  nsCOMPtr<nsILegacyJumpListLink> link = do_QueryInterface(item, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIURI> uri;
+  rv = link->GetUri(getter_AddRefs(uri));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoCString spec;
+  rv = uri->GetSpec(spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Create the IShellItem
+  if (FAILED(SHCreateItemFromParsingName(NS_ConvertASCIItoUTF16(spec).get(),
+                                         nullptr, IID_PPV_ARGS(&psi)))) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  // Set the title
+  nsAutoString linkTitle;
+  link->GetUriTitle(linkTitle);
+
+  IPropertyStore* pPropStore = nullptr;
+  HRESULT hres = psi->GetPropertyStore(GPS_DEFAULT, IID_IPropertyStore,
+                                       (void**)&pPropStore);
+  if (FAILED(hres)) return NS_ERROR_UNEXPECTED;
+
+  PROPVARIANT pv;
+  InitPropVariantFromString(linkTitle.get(), &pv);
+
+  // May fail due to shell item access permissions.
+  pPropStore->SetValue(PKEY_ItemName, pv);
+  pPropStore->Commit();
+  pPropStore->Release();
+
+  PropVariantClear(&pv);
+
+  aShellItem = dont_AddRef(psi);
+
+  return NS_OK;
+}
+
+// (static) For a given IShellItem, create and return a populated
+// nsILegacyJumpListLink.
+nsresult LegacyJumpListLink::GetJumpListLink(
+    IShellItem* pItem, nsCOMPtr<nsILegacyJumpListLink>& aLink) {
+  NS_ENSURE_ARG_POINTER(pItem);
+
+  // We assume for now these are URI links, but through properties we could
+  // query and create other types.
+  nsresult rv;
+  LPWSTR lpstrName = nullptr;
+
+  if (SUCCEEDED(pItem->GetDisplayName(SIGDN_URL, &lpstrName))) {
+    nsCOMPtr<nsIURI> uri;
+    nsAutoString spec(lpstrName);
+
+    rv = NS_NewURI(getter_AddRefs(uri), NS_ConvertUTF16toUTF8(spec));
+    if (NS_FAILED(rv)) return NS_ERROR_INVALID_ARG;
+
+    aLink->SetUri(uri);
+
+    ::CoTaskMemFree(lpstrName);
+  }
+
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/LegacyJumpListItem.h b/widget/windows/LegacyJumpListItem.h
new file mode 100644
index 0000000000..bcef82d349
--- /dev/null
+++ b/widget/windows/LegacyJumpListItem.h
@@ -0,0 +1,133 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __LegacyJumpListItem_h__
+#define __LegacyJumpListItem_h__
+
+#include <windows.h>
+#include <shobjidl.h>
+#undef LogSeverity  // SetupAPI.h #defines this as DWORD
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/LazyIdleThread.h"
+#include "nsILegacyJumpListItem.h"  // defines nsILegacyJumpListItem
+#include "nsIMIMEInfo.h"            // defines nsILocalHandlerApp
+#include "nsTArray.h"
+#include "nsCOMPtr.h"
+#include "nsIURI.h"
+#include "nsICryptoHash.h"
+#include "nsString.h"
+#include "nsCycleCollectionParticipant.h"
+
+class nsIThread;
+
+namespace mozilla {
+namespace widget {
+
+class LegacyJumpListItemBase : public nsILegacyJumpListItem {
+ public:
+  LegacyJumpListItemBase()
+      : mItemType(nsILegacyJumpListItem::JUMPLIST_ITEM_EMPTY) {}
+
+  explicit LegacyJumpListItemBase(int32_t type) : mItemType(type) {}
+
+  NS_DECL_NSILEGACYJUMPLISTITEM
+
+  static const char kJumpListCacheDir[];
+
+ protected:
+  virtual ~LegacyJumpListItemBase() {}
+
+  short Type() { return mItemType; }
+  short mItemType;
+};
+
+class LegacyJumpListItem : public LegacyJumpListItemBase {
+  ~LegacyJumpListItem() {}
+
+ public:
+  using LegacyJumpListItemBase::LegacyJumpListItemBase;
+
+  NS_DECL_ISUPPORTS
+};
+
+class LegacyJumpListSeparator : public LegacyJumpListItemBase,
+                                public nsILegacyJumpListSeparator {
+  ~LegacyJumpListSeparator() {}
+
+ public:
+  LegacyJumpListSeparator()
+      : LegacyJumpListItemBase(nsILegacyJumpListItem::JUMPLIST_ITEM_SEPARATOR) {
+  }
+
+  NS_DECL_ISUPPORTS
+  NS_FORWARD_NSILEGACYJUMPLISTITEM(LegacyJumpListItemBase::)
+
+  static nsresult GetSeparator(RefPtr<IShellLinkW>& aShellLink);
+};
+
+class LegacyJumpListLink : public LegacyJumpListItemBase,
+                           public nsILegacyJumpListLink {
+  ~LegacyJumpListLink() {}
+
+ public:
+  LegacyJumpListLink()
+      : LegacyJumpListItemBase(nsILegacyJumpListItem::JUMPLIST_ITEM_LINK) {}
+
+  NS_DECL_ISUPPORTS
+  NS_IMETHOD GetType(int16_t* aType) override {
+    return LegacyJumpListItemBase::GetType(aType);
+  }
+  NS_IMETHOD Equals(nsILegacyJumpListItem* item, bool* _retval) override;
+  NS_DECL_NSILEGACYJUMPLISTLINK
+
+  static nsresult GetShellItem(nsCOMPtr<nsILegacyJumpListItem>& item,
+                               RefPtr<IShellItem2>& aShellItem);
+  static nsresult GetJumpListLink(IShellItem* pItem,
+                                  nsCOMPtr<nsILegacyJumpListLink>& aLink);
+
+ protected:
+  nsString mUriTitle;
+  nsCOMPtr<nsIURI> mURI;
+  nsCOMPtr<nsICryptoHash> mCryptoHash;
+};
+
+class LegacyJumpListShortcut : public LegacyJumpListItemBase,
+                               public nsILegacyJumpListShortcut {
+  ~LegacyJumpListShortcut() {}
+
+ public:
+  LegacyJumpListShortcut()
+      : LegacyJumpListItemBase(nsILegacyJumpListItem::JUMPLIST_ITEM_SHORTCUT) {}
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(LegacyJumpListShortcut,
+                                           LegacyJumpListItemBase)
+  NS_IMETHOD GetType(int16_t* aType) override {
+    return LegacyJumpListItemBase::GetType(aType);
+  }
+  NS_IMETHOD Equals(nsILegacyJumpListItem* item, bool* _retval) override;
+  NS_DECL_NSILEGACYJUMPLISTSHORTCUT
+
+  static nsresult GetShellLink(nsCOMPtr<nsILegacyJumpListItem>& item,
+                               RefPtr<IShellLinkW>& aShellLink,
+                               RefPtr<LazyIdleThread>& aIOThread);
+  static nsresult GetJumpListShortcut(
+      IShellLinkW* pLink, nsCOMPtr<nsILegacyJumpListShortcut>& aShortcut);
+  static nsresult GetOutputIconPath(nsCOMPtr<nsIURI> aFaviconPageURI,
+                                    nsCOMPtr<nsIFile>& aICOFile);
+
+ protected:
+  int32_t mIconIndex;
+  nsCOMPtr<nsIURI> mFaviconPageURI;
+  nsCOMPtr<nsILocalHandlerApp> mHandlerApp;
+
+  bool ExecutableExists(nsCOMPtr<nsILocalHandlerApp>& handlerApp);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __LegacyJumpListItem_h__ */
diff --git a/widget/windows/MediaKeysEventSourceFactory.cpp b/widget/windows/MediaKeysEventSourceFactory.cpp
new file mode 100644
index 0000000000..525aab19c6
--- /dev/null
+++ b/widget/windows/MediaKeysEventSourceFactory.cpp
@@ -0,0 +1,20 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaKeysEventSourceFactory.h"
+#include "WindowsSMTCProvider.h"
+
+namespace mozilla {
+namespace widget {
+
+mozilla::dom::MediaControlKeySource* CreateMediaControlKeySource() {
+#ifndef __MINGW32__
+  return new WindowsSMTCProvider();
+#else
+  return nullptr;  // MinGW doesn't support the required Windows 8.1+ APIs
+#endif
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/OSKInputPaneManager.cpp b/widget/windows/OSKInputPaneManager.cpp
new file mode 100644
index 0000000000..293a84cd28
--- /dev/null
+++ b/widget/windows/OSKInputPaneManager.cpp
@@ -0,0 +1,101 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#define NTDDI_VERSION NTDDI_WIN10_RS1
+
+#include "OSKInputPaneManager.h"
+#include "nsDebug.h"
+
+#ifndef __MINGW32__
+#  include <inputpaneinterop.h>
+#  include <windows.ui.viewmanagement.h>
+#  include <wrl.h>
+
+using namespace ABI::Windows::UI::ViewManagement;
+using namespace Microsoft::WRL;
+using namespace Microsoft::WRL::Wrappers;
+#endif
+
+namespace mozilla {
+namespace widget {
+
+#ifndef __MINGW32__
+static ComPtr<IInputPane2> GetInputPane(HWND aHwnd) {
+  ComPtr<IInputPaneInterop> inputPaneInterop;
+  HRESULT hr = RoGetActivationFactory(
+      HStringReference(RuntimeClass_Windows_UI_ViewManagement_InputPane).Get(),
+      IID_PPV_ARGS(&inputPaneInterop));
+  if (NS_WARN_IF(FAILED(hr))) {
+    return nullptr;
+  }
+
+  ComPtr<IInputPane> inputPane;
+  hr = inputPaneInterop->GetForWindow(aHwnd, IID_PPV_ARGS(&inputPane));
+  if (NS_WARN_IF(FAILED(hr))) {
+    return nullptr;
+  }
+
+  ComPtr<IInputPane2> inputPane2;
+  inputPane.As(&inputPane2);
+  return inputPane2;
+}
+
+#  ifdef DEBUG
+static bool IsInputPaneVisible(ComPtr<IInputPane2>& aInputPane2) {
+  ComPtr<IInputPaneControl> inputPaneControl;
+  aInputPane2.As(&inputPaneControl);
+  if (NS_WARN_IF(!inputPaneControl)) {
+    return false;
+  }
+  boolean visible = false;
+  inputPaneControl->get_Visible(&visible);
+  return visible;
+}
+
+static bool IsForegroundApp() {
+  HWND foregroundWnd = ::GetForegroundWindow();
+  if (!foregroundWnd) {
+    return false;
+  }
+  DWORD pid;
+  ::GetWindowThreadProcessId(foregroundWnd, &pid);
+  return pid == ::GetCurrentProcessId();
+}
+#  endif
+#endif
+
+// static
+void OSKInputPaneManager::ShowOnScreenKeyboard(HWND aWnd) {
+#ifndef __MINGW32__
+  ComPtr<IInputPane2> inputPane2 = GetInputPane(aWnd);
+  if (!inputPane2) {
+    return;
+  }
+  boolean result;
+  inputPane2->TryShow(&result);
+  NS_WARNING_ASSERTION(
+      result || !IsForegroundApp() || IsInputPaneVisible(inputPane2),
+      "IInputPane2::TryShow is failure");
+#endif
+}
+
+// static
+void OSKInputPaneManager::DismissOnScreenKeyboard(HWND aWnd) {
+#ifndef __MINGW32__
+  ComPtr<IInputPane2> inputPane2 = GetInputPane(aWnd);
+  if (!inputPane2) {
+    return;
+  }
+  boolean result;
+  inputPane2->TryHide(&result);
+  NS_WARNING_ASSERTION(
+      result || !IsForegroundApp() || !IsInputPaneVisible(inputPane2),
+      "IInputPane2::TryHide is failure");
+#endif
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/OSKInputPaneManager.h b/widget/windows/OSKInputPaneManager.h
new file mode 100644
index 0000000000..421a5f1e02
--- /dev/null
+++ b/widget/windows/OSKInputPaneManager.h
@@ -0,0 +1,24 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_OSKInputPaneManager_h
+#define mozilla_widget_OSKInputPaneManager_h
+
+#include <windows.h>
+
+namespace mozilla {
+namespace widget {
+
+class OSKInputPaneManager final {
+ public:
+  static void ShowOnScreenKeyboard(HWND aHwnd);
+  static void DismissOnScreenKeyboard(HWND aHwnd);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_OSKInputPaneManager_h
diff --git a/widget/windows/OSKTabTipManager.cpp b/widget/windows/OSKTabTipManager.cpp
new file mode 100644
index 0000000000..b7b06c08d1
--- /dev/null
+++ b/widget/windows/OSKTabTipManager.cpp
@@ -0,0 +1,112 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "OSKTabTipManager.h"
+
+#include "mozilla/Preferences.h"
+#include "nsDebug.h"
+#include "mozilla/widget/WinRegistry.h"
+
+#include <shellapi.h>
+#include <shlobj.h>
+#include <windows.h>
+
+namespace mozilla {
+namespace widget {
+
+/**
+ * Get the HWND for the on-screen keyboard, if it's up. Only
+ * allowed for Windows 8 and higher.
+ */
+static HWND GetOnScreenKeyboardWindow() {
+  const wchar_t kOSKClassName[] = L"IPTip_Main_Window";
+  HWND osk = ::FindWindowW(kOSKClassName, nullptr);
+  if (::IsWindow(osk) && ::IsWindowEnabled(osk) && ::IsWindowVisible(osk)) {
+    return osk;
+  }
+  return nullptr;
+}
+
+// static
+void OSKTabTipManager::ShowOnScreenKeyboard() {
+  const char* kOskPathPrefName = "ui.osk.on_screen_keyboard_path";
+
+  if (GetOnScreenKeyboardWindow()) {
+    return;
+  }
+
+  nsAutoString cachedPath;
+  nsresult result = Preferences::GetString(kOskPathPrefName, cachedPath);
+  if (NS_FAILED(result) || cachedPath.IsEmpty()) {
+    wchar_t path[MAX_PATH];
+    // The path to TabTip.exe is defined at the following registry key.
+    // This is pulled out of the 64-bit registry hive directly.
+    constexpr auto kRegKeyName =
+        u"Software\\Classes\\CLSID\\{054AAE20-4BEA-4347-8A35-64A533254A9D}\\LocalServer32"_ns;
+    if (!WinRegistry::GetString(HKEY_LOCAL_MACHINE, kRegKeyName, u""_ns, path,
+                                WinRegistry::kLegacyWinUtilsStringFlags)) {
+      return;
+    }
+
+    std::wstring wstrpath(path);
+    // The path provided by the registry will often contain
+    // %CommonProgramFiles%, which will need to be replaced if it is present.
+    size_t commonProgramFilesOffset = wstrpath.find(L"%CommonProgramFiles%");
+    if (commonProgramFilesOffset != std::wstring::npos) {
+      // The path read from the registry contains the %CommonProgramFiles%
+      // environment variable prefix. On 64 bit Windows the
+      // SHGetKnownFolderPath function returns the common program files path
+      // with the X86 suffix for the FOLDERID_ProgramFilesCommon value.
+      // To get the correct path to TabTip.exe we first read the environment
+      // variable CommonProgramW6432 which points to the desired common
+      // files path. Failing that we fallback to the SHGetKnownFolderPath API.
+      // We then replace the %CommonProgramFiles% value with the actual common
+      // files path found in the process.
+      std::wstring commonProgramFilesPath;
+      std::vector<wchar_t> commonProgramFilesPathW6432;
+      DWORD bufferSize =
+          ::GetEnvironmentVariableW(L"CommonProgramW6432", nullptr, 0);
+      if (bufferSize) {
+        commonProgramFilesPathW6432.resize(bufferSize);
+        ::GetEnvironmentVariableW(L"CommonProgramW6432",
+                                  commonProgramFilesPathW6432.data(),
+                                  bufferSize);
+        commonProgramFilesPath =
+            std::wstring(commonProgramFilesPathW6432.data());
+      } else {
+        PWSTR path = nullptr;
+        HRESULT hres = SHGetKnownFolderPath(FOLDERID_ProgramFilesCommon, 0,
+                                            nullptr, &path);
+        if (FAILED(hres) || !path) {
+          return;
+        }
+        commonProgramFilesPath =
+            static_cast<const wchar_t*>(nsDependentString(path).get());
+        ::CoTaskMemFree(path);
+      }
+      wstrpath.replace(commonProgramFilesOffset,
+                       wcslen(L"%CommonProgramFiles%"), commonProgramFilesPath);
+    }
+
+    cachedPath.Assign(wstrpath.data());
+    Preferences::SetString(kOskPathPrefName, cachedPath);
+  }
+
+  const char16_t* cachedPathPtr;
+  cachedPath.GetData(&cachedPathPtr);
+  ShellExecuteW(nullptr, L"", char16ptr_t(cachedPathPtr), nullptr, nullptr,
+                SW_SHOW);
+}
+
+// static
+void OSKTabTipManager::DismissOnScreenKeyboard() {
+  HWND osk = GetOnScreenKeyboardWindow();
+  if (osk) {
+    ::PostMessage(osk, WM_SYSCOMMAND, SC_CLOSE, 0);
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/OSKTabTipManager.h b/widget/windows/OSKTabTipManager.h
new file mode 100644
index 0000000000..231403375b
--- /dev/null
+++ b/widget/windows/OSKTabTipManager.h
@@ -0,0 +1,22 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef OSKTabTipManager_h
+#define OSKTabTipManager_h
+
+namespace mozilla {
+namespace widget {
+
+class OSKTabTipManager final {
+ public:
+  static void ShowOnScreenKeyboard();
+  static void DismissOnScreenKeyboard();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // OSKTabTipManager_h
diff --git a/widget/windows/OSKVRManager.cpp b/widget/windows/OSKVRManager.cpp
new file mode 100644
index 0000000000..158a0f3561
--- /dev/null
+++ b/widget/windows/OSKVRManager.cpp
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "OSKVRManager.h"
+
+#include "FxRWindowManager.h"
+#include "VRShMem.h"
+#include "moz_external_vr.h"
+
+namespace mozilla {
+namespace widget {
+
+// static
+void OSKVRManager::ShowOnScreenKeyboard() {
+#ifdef NIGHTLY_BUILD
+  mozilla::gfx::VRShMem shmem(nullptr, true /*aRequiresMutex*/);
+  shmem.SendIMEState(FxRWindowManager::GetInstance()->GetWindowID(),
+                     mozilla::gfx::VRFxEventState::FOCUS);
+#endif  // NIGHTLY_BUILD
+}
+
+// static
+void OSKVRManager::DismissOnScreenKeyboard() {
+#ifdef NIGHTLY_BUILD
+  mozilla::gfx::VRShMem shmem(nullptr, true /*aRequiresMutex*/);
+  shmem.SendIMEState(FxRWindowManager::GetInstance()->GetWindowID(),
+                     mozilla::gfx::VRFxEventState::BLUR);
+#endif  // NIGHTLY_BUILD
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/OSKVRManager.h b/widget/windows/OSKVRManager.h
new file mode 100644
index 0000000000..7c5a1afa07
--- /dev/null
+++ b/widget/windows/OSKVRManager.h
@@ -0,0 +1,22 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef OSKVRManager_h
+#define OSKVRManager_h
+
+namespace mozilla {
+namespace widget {
+
+class OSKVRManager final {
+ public:
+  static void ShowOnScreenKeyboard();
+  static void DismissOnScreenKeyboard();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // OSKVRManager_h
diff --git a/widget/windows/PCompositorWidget.ipdl b/widget/windows/PCompositorWidget.ipdl
new file mode 100644
index 0000000000..89ea575a47
--- /dev/null
+++ b/widget/windows/PCompositorWidget.ipdl
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=99: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PCompositorBridge;
+
+include "mozilla/dom/TabMessageUtils.h";
+include "mozilla/widget/WidgetMessageUtils.h";
+
+using mozilla::gfx::IntSize from "mozilla/gfx/Point.h";
+using mozilla::WindowsHandle from "mozilla/ipc/IPCTypes.h";
+using mozilla::widget::TransparencyMode from "nsIWidget.h";
+using nsSizeMode from "nsIWidget.h";
+
+namespace mozilla {
+namespace widget {
+
+struct RemoteBackbufferHandles {
+  FileDescriptor fileMapping;
+  FileDescriptor requestReadyEvent;
+  FileDescriptor responseReadyEvent;
+};
+
+[ManualDealloc, ChildImpl=virtual, ParentImpl=virtual]
+sync protocol PCompositorWidget
+{
+  manager PCompositorBridge;
+
+parent:
+  sync Initialize(RemoteBackbufferHandles aRemoteHandles);
+  
+  sync EnterPresentLock();
+  sync LeavePresentLock();
+  async UpdateTransparency(TransparencyMode aMode);
+  async NotifyVisibilityUpdated(nsSizeMode aSizeMode, bool aIsFullyOccluded);
+  sync ClearTransparentWindow();
+  async __delete__();
+
+child:
+  async ObserveVsync();
+  async UnobserveVsync();
+  async UpdateCompositorWnd(WindowsHandle aCompositorWnd, WindowsHandle aParentWnd)
+    returns (bool success);
+};
+
+} // namespace widget
+} // namespace mozilla
diff --git a/widget/windows/PlatformWidgetTypes.ipdlh b/widget/windows/PlatformWidgetTypes.ipdlh
new file mode 100644
index 0000000000..67dd92b802
--- /dev/null
+++ b/widget/windows/PlatformWidgetTypes.ipdlh
@@ -0,0 +1,34 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=99: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include "mozilla/dom/TabMessageUtils.h";
+include "mozilla/widget/WidgetMessageUtils.h";
+
+include HeadlessWidgetTypes;
+
+using mozilla::WindowsHandle from "mozilla/ipc/IPCTypes.h";
+using nsSizeMode from "nsIWidgetListener.h";
+using mozilla::widget::TransparencyMode from "nsIWidget.h";
+
+namespace mozilla {
+namespace widget {
+
+struct WinCompositorWidgetInitData
+{
+  WindowsHandle hWnd;
+  uintptr_t widgetKey;
+  TransparencyMode transparencyMode;
+  nsSizeMode sizeMode;
+};
+
+union CompositorWidgetInitData
+{
+  WinCompositorWidgetInitData;
+  HeadlessCompositorWidgetInitData;
+};
+
+} // namespace widget
+} // namespace mozilla
diff --git a/widget/windows/RemoteBackbuffer.cpp b/widget/windows/RemoteBackbuffer.cpp
new file mode 100644
index 0000000000..56a8bae0fe
--- /dev/null
+++ b/widget/windows/RemoteBackbuffer.cpp
@@ -0,0 +1,713 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "RemoteBackbuffer.h"
+#include "GeckoProfiler.h"
+#include "nsThreadUtils.h"
+#include "mozilla/Span.h"
+#include "mozilla/gfx/Point.h"
+#include "WinUtils.h"
+#include <algorithm>
+#include <type_traits>
+
+namespace mozilla {
+namespace widget {
+namespace remote_backbuffer {
+
+// This number can be adjusted as a time-memory tradeoff
+constexpr uint8_t kMaxDirtyRects = 8;
+
+struct IpcSafeRect {
+  explicit IpcSafeRect(const gfx::IntRect& aRect)
+      : x(aRect.x), y(aRect.y), width(aRect.width), height(aRect.height) {}
+  int32_t x;
+  int32_t y;
+  int32_t width;
+  int32_t height;
+};
+
+enum class ResponseResult {
+  Unknown,
+  Error,
+  BorrowSuccess,
+  BorrowSameBuffer,
+  PresentSuccess
+};
+
+enum class SharedDataType {
+  BorrowRequest,
+  BorrowRequestAllowSameBuffer,
+  BorrowResponse,
+  PresentRequest,
+  PresentResponse
+};
+
+struct BorrowResponseData {
+  ResponseResult result;
+  int32_t width;
+  int32_t height;
+  HANDLE fileMapping;
+};
+
+struct PresentRequestData {
+  uint8_t lenDirtyRects;
+  IpcSafeRect dirtyRects[kMaxDirtyRects];
+};
+
+struct PresentResponseData {
+  ResponseResult result;
+};
+
+struct SharedData {
+  SharedDataType dataType;
+  union {
+    BorrowResponseData borrowResponse;
+    PresentRequestData presentRequest;
+    PresentResponseData presentResponse;
+  } data;
+};
+
+static_assert(std::is_trivially_copyable<SharedData>::value &&
+                  std::is_standard_layout<SharedData>::value,
+              "SharedData must be safe to pass over IPC boundaries");
+
+class SharedImage {
+ public:
+  SharedImage()
+      : mWidth(0), mHeight(0), mFileMapping(nullptr), mPixelData(nullptr) {}
+
+  ~SharedImage() {
+    if (mPixelData) {
+      MOZ_ALWAYS_TRUE(::UnmapViewOfFile(mPixelData));
+    }
+
+    if (mFileMapping) {
+      MOZ_ALWAYS_TRUE(::CloseHandle(mFileMapping));
+    }
+  }
+
+  bool Initialize(int32_t aWidth, int32_t aHeight) {
+    MOZ_ASSERT(aWidth > 0);
+    MOZ_ASSERT(aHeight > 0);
+
+    mWidth = aWidth;
+    mHeight = aHeight;
+
+    DWORD bufferSize = static_cast<DWORD>(mHeight * GetStride());
+
+    mFileMapping = ::CreateFileMappingW(
+        INVALID_HANDLE_VALUE, nullptr /*secattr*/, PAGE_READWRITE,
+        0 /*sizeHigh*/, bufferSize, nullptr /*name*/);
+    if (!mFileMapping) {
+      return false;
+    }
+
+    void* mappedFilePtr =
+        ::MapViewOfFile(mFileMapping, FILE_MAP_ALL_ACCESS, 0 /*offsetHigh*/,
+                        0 /*offsetLow*/, 0 /*bytesToMap*/);
+    if (!mappedFilePtr) {
+      return false;
+    }
+
+    mPixelData = reinterpret_cast<unsigned char*>(mappedFilePtr);
+
+    return true;
+  }
+
+  bool InitializeRemote(int32_t aWidth, int32_t aHeight, HANDLE aFileMapping) {
+    MOZ_ASSERT(aWidth > 0);
+    MOZ_ASSERT(aHeight > 0);
+    MOZ_ASSERT(aFileMapping);
+
+    mWidth = aWidth;
+    mHeight = aHeight;
+    mFileMapping = aFileMapping;
+
+    void* mappedFilePtr =
+        ::MapViewOfFile(mFileMapping, FILE_MAP_ALL_ACCESS, 0 /*offsetHigh*/,
+                        0 /*offsetLow*/, 0 /*bytesToMap*/);
+    if (!mappedFilePtr) {
+      return false;
+    }
+
+    mPixelData = reinterpret_cast<unsigned char*>(mappedFilePtr);
+
+    return true;
+  }
+
+  HBITMAP CreateDIBSection() {
+    BITMAPINFO bitmapInfo = {};
+    bitmapInfo.bmiHeader.biSize = sizeof(bitmapInfo.bmiHeader);
+    bitmapInfo.bmiHeader.biWidth = mWidth;
+    bitmapInfo.bmiHeader.biHeight = -mHeight;
+    bitmapInfo.bmiHeader.biPlanes = 1;
+    bitmapInfo.bmiHeader.biBitCount = 32;
+    bitmapInfo.bmiHeader.biCompression = BI_RGB;
+    void* dummy = nullptr;
+    return ::CreateDIBSection(nullptr /*paletteDC*/, &bitmapInfo,
+                              DIB_RGB_COLORS, &dummy, mFileMapping,
+                              0 /*offset*/);
+  }
+
+  HANDLE CreateRemoteFileMapping(HANDLE aTargetProcess) {
+    MOZ_ASSERT(aTargetProcess);
+
+    HANDLE fileMapping = nullptr;
+    if (!::DuplicateHandle(GetCurrentProcess(), mFileMapping, aTargetProcess,
+                           &fileMapping, 0 /*desiredAccess*/,
+                           FALSE /*inheritHandle*/, DUPLICATE_SAME_ACCESS)) {
+      return nullptr;
+    }
+    return fileMapping;
+  }
+
+  already_AddRefed<gfx::DrawTarget> CreateDrawTarget() {
+    return gfx::Factory::CreateDrawTargetForData(
+        gfx::BackendType::CAIRO, mPixelData, gfx::IntSize(mWidth, mHeight),
+        GetStride(), gfx::SurfaceFormat::B8G8R8A8);
+  }
+
+  void CopyPixelsFrom(const SharedImage& other) {
+    const unsigned char* src = other.mPixelData;
+    unsigned char* dst = mPixelData;
+
+    int32_t width = std::min(mWidth, other.mWidth);
+    int32_t height = std::min(mHeight, other.mHeight);
+
+    for (int32_t row = 0; row < height; ++row) {
+      memcpy(dst, src, static_cast<uint32_t>(width * kBytesPerPixel));
+      src += other.GetStride();
+      dst += GetStride();
+    }
+  }
+
+  int32_t GetWidth() { return mWidth; }
+
+  int32_t GetHeight() { return mHeight; }
+
+  SharedImage(const SharedImage&) = delete;
+  SharedImage(SharedImage&&) = delete;
+  SharedImage& operator=(const SharedImage&) = delete;
+  SharedImage& operator=(SharedImage&&) = delete;
+
+ private:
+  static constexpr int32_t kBytesPerPixel = 4;
+
+  int32_t GetStride() const {
+    // DIB requires 32-bit row alignment
+    return (((mWidth * kBytesPerPixel) + 3) / 4) * 4;
+  }
+
+  int32_t mWidth;
+  int32_t mHeight;
+  HANDLE mFileMapping;
+  unsigned char* mPixelData;
+};
+
+class PresentableSharedImage {
+ public:
+  PresentableSharedImage()
+      : mSharedImage(),
+        mDeviceContext(nullptr),
+        mDIBSection(nullptr),
+        mSavedObject(nullptr) {}
+
+  ~PresentableSharedImage() {
+    if (mSavedObject) {
+      MOZ_ALWAYS_TRUE(::SelectObject(mDeviceContext, mSavedObject));
+    }
+
+    if (mDIBSection) {
+      MOZ_ALWAYS_TRUE(::DeleteObject(mDIBSection));
+    }
+
+    if (mDeviceContext) {
+      MOZ_ALWAYS_TRUE(::DeleteDC(mDeviceContext));
+    }
+  }
+
+  bool Initialize(int32_t aWidth, int32_t aHeight) {
+    if (!mSharedImage.Initialize(aWidth, aHeight)) {
+      return false;
+    }
+
+    mDeviceContext = ::CreateCompatibleDC(nullptr);
+    if (!mDeviceContext) {
+      return false;
+    }
+
+    mDIBSection = mSharedImage.CreateDIBSection();
+    if (!mDIBSection) {
+      return false;
+    }
+
+    mSavedObject = ::SelectObject(mDeviceContext, mDIBSection);
+    if (!mSavedObject) {
+      return false;
+    }
+
+    return true;
+  }
+
+  bool PresentToWindow(HWND aWindowHandle, TransparencyMode aTransparencyMode,
+                       Span<const IpcSafeRect> aDirtyRects) {
+    if (aTransparencyMode == TransparencyMode::Transparent) {
+      // If our window is a child window or a child-of-a-child, the window
+      // that needs to be updated is the top level ancestor of the tree
+      HWND topLevelWindow = WinUtils::GetTopLevelHWND(aWindowHandle, true);
+      MOZ_ASSERT(::GetWindowLongPtr(topLevelWindow, GWL_EXSTYLE) &
+                 WS_EX_LAYERED);
+
+      BLENDFUNCTION bf = {AC_SRC_OVER, 0, 255, AC_SRC_ALPHA};
+      POINT srcPos = {0, 0};
+      RECT clientRect = {};
+      if (!::GetClientRect(aWindowHandle, &clientRect)) {
+        return false;
+      }
+      MOZ_ASSERT(clientRect.left == 0);
+      MOZ_ASSERT(clientRect.top == 0);
+      int32_t width = clientRect.right;
+      int32_t height = clientRect.bottom;
+      SIZE winSize = {width, height};
+      // Window resize could cause the client area to be different than
+      // mSharedImage's size. If the client area doesn't match,
+      // PresentToWindow() returns false without calling UpdateLayeredWindow().
+      // Another call to UpdateLayeredWindow() will follow shortly, since the
+      // resize will eventually force the backbuffer to repaint itself again.
+      // When client area is larger than mSharedImage's size,
+      // UpdateLayeredWindow() draws the window completely invisible. But it
+      // does not return false.
+      if (width != mSharedImage.GetWidth() ||
+          height != mSharedImage.GetHeight()) {
+        return false;
+      }
+
+      return !!::UpdateLayeredWindow(
+          topLevelWindow, nullptr /*paletteDC*/, nullptr /*newPos*/, &winSize,
+          mDeviceContext, &srcPos, 0 /*colorKey*/, &bf, ULW_ALPHA);
+    }
+
+    gfx::IntRect sharedImageRect{0, 0, mSharedImage.GetWidth(),
+                                 mSharedImage.GetHeight()};
+
+    bool result = true;
+
+    HDC windowDC = ::GetDC(aWindowHandle);
+    if (!windowDC) {
+      return false;
+    }
+
+    for (auto& ipcDirtyRect : aDirtyRects) {
+      gfx::IntRect dirtyRect{ipcDirtyRect.x, ipcDirtyRect.y, ipcDirtyRect.width,
+                             ipcDirtyRect.height};
+      gfx::IntRect bltRect = dirtyRect.Intersect(sharedImageRect);
+
+      if (!::BitBlt(windowDC, bltRect.x /*dstX*/, bltRect.y /*dstY*/,
+                    bltRect.width, bltRect.height, mDeviceContext,
+                    bltRect.x /*srcX*/, bltRect.y /*srcY*/, SRCCOPY)) {
+        result = false;
+        break;
+      }
+    }
+
+    MOZ_ALWAYS_TRUE(::ReleaseDC(aWindowHandle, windowDC));
+
+    return result;
+  }
+
+  HANDLE CreateRemoteFileMapping(HANDLE aTargetProcess) {
+    return mSharedImage.CreateRemoteFileMapping(aTargetProcess);
+  }
+
+  already_AddRefed<gfx::DrawTarget> CreateDrawTarget() {
+    return mSharedImage.CreateDrawTarget();
+  }
+
+  void CopyPixelsFrom(const PresentableSharedImage& other) {
+    mSharedImage.CopyPixelsFrom(other.mSharedImage);
+  }
+
+  int32_t GetWidth() { return mSharedImage.GetWidth(); }
+
+  int32_t GetHeight() { return mSharedImage.GetHeight(); }
+
+  PresentableSharedImage(const PresentableSharedImage&) = delete;
+  PresentableSharedImage(PresentableSharedImage&&) = delete;
+  PresentableSharedImage& operator=(const PresentableSharedImage&) = delete;
+  PresentableSharedImage& operator=(PresentableSharedImage&&) = delete;
+
+ private:
+  SharedImage mSharedImage;
+  HDC mDeviceContext;
+  HBITMAP mDIBSection;
+  HGDIOBJ mSavedObject;
+};
+
+Provider::Provider()
+    : mWindowHandle(nullptr),
+      mTargetProcess(nullptr),
+      mFileMapping(nullptr),
+      mRequestReadyEvent(nullptr),
+      mResponseReadyEvent(nullptr),
+      mSharedDataPtr(nullptr),
+      mStopServiceThread(false),
+      mServiceThread(nullptr),
+      mBackbuffer() {}
+
+Provider::~Provider() {
+  mBackbuffer.reset();
+
+  if (mServiceThread) {
+    mStopServiceThread = true;
+    MOZ_ALWAYS_TRUE(::SetEvent(mRequestReadyEvent));
+    MOZ_ALWAYS_TRUE(PR_JoinThread(mServiceThread) == PR_SUCCESS);
+  }
+
+  if (mSharedDataPtr) {
+    MOZ_ALWAYS_TRUE(::UnmapViewOfFile(mSharedDataPtr));
+  }
+
+  if (mResponseReadyEvent) {
+    MOZ_ALWAYS_TRUE(::CloseHandle(mResponseReadyEvent));
+  }
+
+  if (mRequestReadyEvent) {
+    MOZ_ALWAYS_TRUE(::CloseHandle(mRequestReadyEvent));
+  }
+
+  if (mFileMapping) {
+    MOZ_ALWAYS_TRUE(::CloseHandle(mFileMapping));
+  }
+
+  if (mTargetProcess) {
+    MOZ_ALWAYS_TRUE(::CloseHandle(mTargetProcess));
+  }
+}
+
+bool Provider::Initialize(HWND aWindowHandle, DWORD aTargetProcessId,
+                          TransparencyMode aTransparencyMode) {
+  MOZ_ASSERT(aWindowHandle);
+  MOZ_ASSERT(aTargetProcessId);
+
+  mWindowHandle = aWindowHandle;
+
+  mTargetProcess = ::OpenProcess(PROCESS_DUP_HANDLE, FALSE /*inheritHandle*/,
+                                 aTargetProcessId);
+  if (!mTargetProcess) {
+    return false;
+  }
+
+  mFileMapping = ::CreateFileMappingW(
+      INVALID_HANDLE_VALUE, nullptr /*secattr*/, PAGE_READWRITE, 0 /*sizeHigh*/,
+      static_cast<DWORD>(sizeof(SharedData)), nullptr /*name*/);
+  if (!mFileMapping) {
+    return false;
+  }
+
+  mRequestReadyEvent =
+      ::CreateEventW(nullptr /*secattr*/, FALSE /*manualReset*/,
+                     FALSE /*initialState*/, nullptr /*name*/);
+  if (!mRequestReadyEvent) {
+    return false;
+  }
+
+  mResponseReadyEvent =
+      ::CreateEventW(nullptr /*secattr*/, FALSE /*manualReset*/,
+                     FALSE /*initialState*/, nullptr /*name*/);
+  if (!mResponseReadyEvent) {
+    return false;
+  }
+
+  void* mappedFilePtr =
+      ::MapViewOfFile(mFileMapping, FILE_MAP_ALL_ACCESS, 0 /*offsetHigh*/,
+                      0 /*offsetLow*/, 0 /*bytesToMap*/);
+  if (!mappedFilePtr) {
+    return false;
+  }
+
+  mSharedDataPtr = reinterpret_cast<SharedData*>(mappedFilePtr);
+
+  mStopServiceThread = false;
+
+  // Use a raw NSPR OS-level thread here instead of nsThread because we are
+  // performing low-level synchronization across processes using Win32 Events,
+  // and nsThread is designed around an incompatible "in-process task queue"
+  // model
+  mServiceThread = PR_CreateThread(
+      PR_USER_THREAD, [](void* p) { static_cast<Provider*>(p)->ThreadMain(); },
+      this, PR_PRIORITY_NORMAL, PR_GLOBAL_THREAD, PR_JOINABLE_THREAD,
+      0 /*default stack size*/);
+  if (!mServiceThread) {
+    return false;
+  }
+
+  mTransparencyMode = uint32_t(aTransparencyMode);
+
+  return true;
+}
+
+Maybe<RemoteBackbufferHandles> Provider::CreateRemoteHandles() {
+  return Some(
+      RemoteBackbufferHandles(ipc::FileDescriptor(mFileMapping),
+                              ipc::FileDescriptor(mRequestReadyEvent),
+                              ipc::FileDescriptor(mResponseReadyEvent)));
+}
+
+void Provider::UpdateTransparencyMode(TransparencyMode aTransparencyMode) {
+  mTransparencyMode = uint32_t(aTransparencyMode);
+}
+
+void Provider::ThreadMain() {
+  AUTO_PROFILER_REGISTER_THREAD("RemoteBackbuffer");
+  NS_SetCurrentThreadName("RemoteBackbuffer");
+
+  while (true) {
+    {
+      AUTO_PROFILER_THREAD_SLEEP;
+      MOZ_ALWAYS_TRUE(::WaitForSingleObject(mRequestReadyEvent, INFINITE) ==
+                      WAIT_OBJECT_0);
+    }
+
+    if (mStopServiceThread) {
+      break;
+    }
+
+    switch (mSharedDataPtr->dataType) {
+      case SharedDataType::BorrowRequest:
+      case SharedDataType::BorrowRequestAllowSameBuffer: {
+        BorrowResponseData responseData = {};
+
+        HandleBorrowRequest(&responseData,
+                            mSharedDataPtr->dataType ==
+                                SharedDataType::BorrowRequestAllowSameBuffer);
+
+        mSharedDataPtr->dataType = SharedDataType::BorrowResponse;
+        mSharedDataPtr->data.borrowResponse = responseData;
+
+        MOZ_ALWAYS_TRUE(::SetEvent(mResponseReadyEvent));
+
+        break;
+      }
+      case SharedDataType::PresentRequest: {
+        PresentRequestData requestData = mSharedDataPtr->data.presentRequest;
+        PresentResponseData responseData = {};
+
+        HandlePresentRequest(requestData, &responseData);
+
+        mSharedDataPtr->dataType = SharedDataType::PresentResponse;
+        mSharedDataPtr->data.presentResponse = responseData;
+
+        MOZ_ALWAYS_TRUE(::SetEvent(mResponseReadyEvent));
+
+        break;
+      }
+      default:
+        break;
+    };
+  }
+}
+
+void Provider::HandleBorrowRequest(BorrowResponseData* aResponseData,
+                                   bool aAllowSameBuffer) {
+  MOZ_ASSERT(aResponseData);
+
+  aResponseData->result = ResponseResult::Error;
+
+  RECT clientRect = {};
+  if (!::GetClientRect(mWindowHandle, &clientRect)) {
+    return;
+  }
+
+  MOZ_ASSERT(clientRect.left == 0);
+  MOZ_ASSERT(clientRect.top == 0);
+
+  int32_t width = clientRect.right ? clientRect.right : 1;
+  int32_t height = clientRect.bottom ? clientRect.bottom : 1;
+
+  bool needNewBackbuffer = !aAllowSameBuffer || !mBackbuffer ||
+                           (mBackbuffer->GetWidth() != width) ||
+                           (mBackbuffer->GetHeight() != height);
+
+  if (!needNewBackbuffer) {
+    aResponseData->result = ResponseResult::BorrowSameBuffer;
+    return;
+  }
+
+  auto newBackbuffer = std::make_unique<PresentableSharedImage>();
+  if (!newBackbuffer->Initialize(width, height)) {
+    return;
+  }
+
+  // Preserve the contents of the old backbuffer (if it exists)
+  if (mBackbuffer) {
+    newBackbuffer->CopyPixelsFrom(*mBackbuffer);
+    mBackbuffer.reset();
+  }
+
+  HANDLE remoteFileMapping =
+      newBackbuffer->CreateRemoteFileMapping(mTargetProcess);
+  if (!remoteFileMapping) {
+    return;
+  }
+
+  aResponseData->result = ResponseResult::BorrowSuccess;
+  aResponseData->width = width;
+  aResponseData->height = height;
+  aResponseData->fileMapping = remoteFileMapping;
+
+  mBackbuffer = std::move(newBackbuffer);
+}
+
+void Provider::HandlePresentRequest(const PresentRequestData& aRequestData,
+                                    PresentResponseData* aResponseData) {
+  MOZ_ASSERT(aResponseData);
+
+  Span rectSpan(aRequestData.dirtyRects, kMaxDirtyRects);
+
+  aResponseData->result = ResponseResult::Error;
+
+  if (!mBackbuffer) {
+    return;
+  }
+
+  if (!mBackbuffer->PresentToWindow(
+          mWindowHandle, GetTransparencyMode(),
+          rectSpan.First(aRequestData.lenDirtyRects))) {
+    return;
+  }
+
+  aResponseData->result = ResponseResult::PresentSuccess;
+}
+
+Client::Client()
+    : mFileMapping(nullptr),
+      mRequestReadyEvent(nullptr),
+      mResponseReadyEvent(nullptr),
+      mSharedDataPtr(nullptr),
+      mBackbuffer() {}
+
+Client::~Client() {
+  mBackbuffer.reset();
+
+  if (mSharedDataPtr) {
+    MOZ_ALWAYS_TRUE(::UnmapViewOfFile(mSharedDataPtr));
+  }
+
+  if (mResponseReadyEvent) {
+    MOZ_ALWAYS_TRUE(::CloseHandle(mResponseReadyEvent));
+  }
+
+  if (mRequestReadyEvent) {
+    MOZ_ALWAYS_TRUE(::CloseHandle(mRequestReadyEvent));
+  }
+
+  if (mFileMapping) {
+    MOZ_ALWAYS_TRUE(::CloseHandle(mFileMapping));
+  }
+}
+
+bool Client::Initialize(const RemoteBackbufferHandles& aRemoteHandles) {
+  MOZ_ASSERT(aRemoteHandles.fileMapping().IsValid());
+  MOZ_ASSERT(aRemoteHandles.requestReadyEvent().IsValid());
+  MOZ_ASSERT(aRemoteHandles.responseReadyEvent().IsValid());
+
+  // FIXME: Due to PCompositorWidget using virtual Recv methods,
+  // RemoteBackbufferHandles is passed by const reference, and cannot have its
+  // signature customized, meaning that we need to clone the handles here.
+  //
+  // Once PCompositorWidget is migrated to use direct call semantics, the
+  // signature can be changed to accept RemoteBackbufferHandles by rvalue
+  // reference or value, and the DuplicateHandle calls here can be avoided.
+  mFileMapping = aRemoteHandles.fileMapping().ClonePlatformHandle().release();
+  mRequestReadyEvent =
+      aRemoteHandles.requestReadyEvent().ClonePlatformHandle().release();
+  mResponseReadyEvent =
+      aRemoteHandles.responseReadyEvent().ClonePlatformHandle().release();
+
+  void* mappedFilePtr =
+      ::MapViewOfFile(mFileMapping, FILE_MAP_ALL_ACCESS, 0 /*offsetHigh*/,
+                      0 /*offsetLow*/, 0 /*bytesToMap*/);
+  if (!mappedFilePtr) {
+    return false;
+  }
+
+  mSharedDataPtr = reinterpret_cast<SharedData*>(mappedFilePtr);
+
+  return true;
+}
+
+already_AddRefed<gfx::DrawTarget> Client::BorrowDrawTarget() {
+  mSharedDataPtr->dataType = mBackbuffer
+                                 ? SharedDataType::BorrowRequestAllowSameBuffer
+                                 : SharedDataType::BorrowRequest;
+
+  MOZ_ALWAYS_TRUE(::SetEvent(mRequestReadyEvent));
+  MOZ_ALWAYS_TRUE(::WaitForSingleObject(mResponseReadyEvent, INFINITE) ==
+                  WAIT_OBJECT_0);
+
+  if (mSharedDataPtr->dataType != SharedDataType::BorrowResponse) {
+    return nullptr;
+  }
+
+  BorrowResponseData responseData = mSharedDataPtr->data.borrowResponse;
+
+  if ((responseData.result != ResponseResult::BorrowSameBuffer) &&
+      (responseData.result != ResponseResult::BorrowSuccess)) {
+    return nullptr;
+  }
+
+  if (responseData.result == ResponseResult::BorrowSuccess) {
+    mBackbuffer.reset();
+
+    auto newBackbuffer = std::make_unique<SharedImage>();
+    if (!newBackbuffer->InitializeRemote(responseData.width,
+                                         responseData.height,
+                                         responseData.fileMapping)) {
+      return nullptr;
+    }
+
+    mBackbuffer = std::move(newBackbuffer);
+  }
+
+  MOZ_ASSERT(mBackbuffer);
+
+  return mBackbuffer->CreateDrawTarget();
+}
+
+bool Client::PresentDrawTarget(gfx::IntRegion aDirtyRegion) {
+  mSharedDataPtr->dataType = SharedDataType::PresentRequest;
+
+  // Simplify the region until it has <= kMaxDirtyRects
+  aDirtyRegion.SimplifyOutward(kMaxDirtyRects);
+
+  Span rectSpan(mSharedDataPtr->data.presentRequest.dirtyRects, kMaxDirtyRects);
+
+  uint8_t rectIndex = 0;
+  for (auto iter = aDirtyRegion.RectIter(); !iter.Done(); iter.Next()) {
+    rectSpan[rectIndex] = IpcSafeRect(iter.Get());
+    ++rectIndex;
+  }
+
+  mSharedDataPtr->data.presentRequest.lenDirtyRects = rectIndex;
+
+  MOZ_ALWAYS_TRUE(::SetEvent(mRequestReadyEvent));
+  MOZ_ALWAYS_TRUE(::WaitForSingleObject(mResponseReadyEvent, INFINITE) ==
+                  WAIT_OBJECT_0);
+
+  if (mSharedDataPtr->dataType != SharedDataType::PresentResponse) {
+    return false;
+  }
+
+  if (mSharedDataPtr->data.presentResponse.result !=
+      ResponseResult::PresentSuccess) {
+    return false;
+  }
+
+  return true;
+}
+
+}  // namespace remote_backbuffer
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/RemoteBackbuffer.h b/widget/windows/RemoteBackbuffer.h
new file mode 100644
index 0000000000..5899e80984
--- /dev/null
+++ b/widget/windows/RemoteBackbuffer.h
@@ -0,0 +1,95 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_RemoteBackbuffer_h
+#define widget_windows_RemoteBackbuffer_h
+
+#include "nsIWidget.h"
+#include "mozilla/widget/PCompositorWidgetParent.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/gfx/2D.h"
+#include "prthread.h"
+#include <windows.h>
+
+namespace mozilla {
+namespace widget {
+namespace remote_backbuffer {
+
+struct IpcRect;
+struct SharedData;
+struct BorrowResponseData;
+struct PresentRequestData;
+struct PresentResponseData;
+class SharedImage;
+class PresentableSharedImage;
+
+class Provider {
+ public:
+  Provider();
+  ~Provider();
+
+  bool Initialize(HWND aWindowHandle, DWORD aTargetProcessId,
+                  TransparencyMode aTransparencyMode);
+
+  Maybe<RemoteBackbufferHandles> CreateRemoteHandles();
+
+  void UpdateTransparencyMode(TransparencyMode aTransparencyMode);
+
+  Provider(const Provider&) = delete;
+  Provider(Provider&&) = delete;
+  Provider& operator=(const Provider&) = delete;
+  Provider& operator=(Provider&&) = delete;
+
+ private:
+  void ThreadMain();
+
+  void HandleBorrowRequest(BorrowResponseData* aResponseData,
+                           bool aAllowSameBuffer);
+  void HandlePresentRequest(const PresentRequestData& aRequestData,
+                            PresentResponseData* aResponseData);
+
+  HWND mWindowHandle;
+  HANDLE mTargetProcess;
+  HANDLE mFileMapping;
+  HANDLE mRequestReadyEvent;
+  HANDLE mResponseReadyEvent;
+  SharedData* mSharedDataPtr;
+  bool mStopServiceThread;
+  PRThread* mServiceThread;
+  std::unique_ptr<PresentableSharedImage> mBackbuffer;
+  mozilla::Atomic<uint32_t, MemoryOrdering::Relaxed> mTransparencyMode;
+  TransparencyMode GetTransparencyMode() const {
+    return TransparencyMode(uint32_t(mTransparencyMode));
+  }
+};
+
+class Client {
+ public:
+  Client();
+  ~Client();
+
+  bool Initialize(const RemoteBackbufferHandles& aRemoteHandles);
+
+  already_AddRefed<gfx::DrawTarget> BorrowDrawTarget();
+  bool PresentDrawTarget(gfx::IntRegion aDirtyRegion);
+
+  Client(const Client&) = delete;
+  Client(Client&&) = delete;
+  Client& operator=(const Client&) = delete;
+  Client& operator=(Client&&) = delete;
+
+ private:
+  HANDLE mFileMapping;
+  HANDLE mRequestReadyEvent;
+  HANDLE mResponseReadyEvent;
+  SharedData* mSharedDataPtr;
+  std::unique_ptr<SharedImage> mBackbuffer;
+};
+
+}  // namespace remote_backbuffer
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_windows_RemoteBackbuffer_h
diff --git a/widget/windows/ScreenHelperWin.cpp b/widget/windows/ScreenHelperWin.cpp
new file mode 100644
index 0000000000..8a0ec3b608
--- /dev/null
+++ b/widget/windows/ScreenHelperWin.cpp
@@ -0,0 +1,157 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ScreenHelperWin.h"
+
+#include "mozilla/Logging.h"
+#include "nsTArray.h"
+#include "WinUtils.h"
+
+static mozilla::LazyLogModule sScreenLog("WidgetScreen");
+
+namespace mozilla {
+namespace widget {
+
+static void GetDisplayInfo(const char16ptr_t aName,
+                           hal::ScreenOrientation& aOrientation,
+                           uint16_t& aAngle, bool& aIsPseudoDisplay,
+                           uint32_t& aRefreshRate) {
+  DISPLAY_DEVICEW displayDevice = {.cb = sizeof(DISPLAY_DEVICEW)};
+
+  // XXX Is the pseudodisplay status really useful?
+  aIsPseudoDisplay =
+      EnumDisplayDevicesW(aName, 0, &displayDevice, 0) &&
+      (displayDevice.StateFlags & DISPLAY_DEVICE_MIRRORING_DRIVER);
+
+  DEVMODEW mode = {.dmSize = sizeof(DEVMODEW)};
+  if (!EnumDisplaySettingsW(aName, ENUM_CURRENT_SETTINGS, &mode)) {
+    return;
+  }
+  MOZ_ASSERT(mode.dmFields & DM_DISPLAYORIENTATION);
+
+  aRefreshRate = mode.dmDisplayFrequency;
+
+  // conver to default/natural size
+  if (mode.dmDisplayOrientation == DMDO_90 ||
+      mode.dmDisplayOrientation == DMDO_270) {
+    DWORD temp = mode.dmPelsHeight;
+    mode.dmPelsHeight = mode.dmPelsWidth;
+    mode.dmPelsWidth = temp;
+  }
+
+  bool defaultIsLandscape = mode.dmPelsWidth >= mode.dmPelsHeight;
+  switch (mode.dmDisplayOrientation) {
+    case DMDO_DEFAULT:
+      aOrientation = defaultIsLandscape
+                         ? hal::ScreenOrientation::LandscapePrimary
+                         : hal::ScreenOrientation::PortraitPrimary;
+      aAngle = 0;
+      break;
+    case DMDO_90:
+      aOrientation = defaultIsLandscape
+                         ? hal::ScreenOrientation::PortraitPrimary
+                         : hal::ScreenOrientation::LandscapeSecondary;
+      aAngle = 270;
+      break;
+    case DMDO_180:
+      aOrientation = defaultIsLandscape
+                         ? hal::ScreenOrientation::LandscapeSecondary
+                         : hal::ScreenOrientation::PortraitSecondary;
+      aAngle = 180;
+      break;
+    case DMDO_270:
+      aOrientation = defaultIsLandscape
+                         ? hal::ScreenOrientation::PortraitSecondary
+                         : hal::ScreenOrientation::LandscapePrimary;
+      aAngle = 90;
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE("Unexpected angle");
+      break;
+  }
+}
+
+BOOL CALLBACK CollectMonitors(HMONITOR aMon, HDC, LPRECT, LPARAM ioParam) {
+  auto screens = reinterpret_cast<nsTArray<RefPtr<Screen>>*>(ioParam);
+  BOOL success = FALSE;
+  MONITORINFOEX info;
+  info.cbSize = sizeof(MONITORINFOEX);
+  success = ::GetMonitorInfoW(aMon, &info);
+  if (!success) {
+    MOZ_LOG(sScreenLog, LogLevel::Error, ("GetMonitorInfoW failed"));
+    return TRUE;  // continue the enumeration
+  }
+
+  double scale = WinUtils::LogToPhysFactor(aMon);
+  DesktopToLayoutDeviceScale contentsScaleFactor;
+  if (WinUtils::IsPerMonitorDPIAware()) {
+    contentsScaleFactor.scale = 1.0;
+  } else {
+    contentsScaleFactor.scale = scale;
+  }
+  CSSToLayoutDeviceScale defaultCssScaleFactor(scale);
+  LayoutDeviceIntRect rect(info.rcMonitor.left, info.rcMonitor.top,
+                           info.rcMonitor.right - info.rcMonitor.left,
+                           info.rcMonitor.bottom - info.rcMonitor.top);
+  LayoutDeviceIntRect availRect(info.rcWork.left, info.rcWork.top,
+                                info.rcWork.right - info.rcWork.left,
+                                info.rcWork.bottom - info.rcWork.top);
+
+  HDC hDC = CreateDC(nullptr, info.szDevice, nullptr, nullptr);
+  if (!hDC) {
+    MOZ_LOG(sScreenLog, LogLevel::Error, ("CollectMonitors CreateDC failed"));
+    return TRUE;
+  }
+  uint32_t pixelDepth = ::GetDeviceCaps(hDC, BITSPIXEL);
+  DeleteDC(hDC);
+  if (pixelDepth == 32) {
+    // If a device uses 32 bits per pixel, it's still only using 8 bits
+    // per color component, which is what our callers want to know.
+    // (Some devices report 32 and some devices report 24.)
+    pixelDepth = 24;
+  }
+
+  float dpi = WinUtils::MonitorDPI(aMon);
+
+  auto orientation = hal::ScreenOrientation::None;
+  uint16_t angle = 0;
+  bool isPseudoDisplay = false;
+  uint32_t refreshRate = 0;
+  GetDisplayInfo(info.szDevice, orientation, angle, isPseudoDisplay,
+                 refreshRate);
+
+  MOZ_LOG(sScreenLog, LogLevel::Debug,
+          ("New screen [%s (%s) %d %u %f %f %f %d %d %d]",
+           ToString(rect).c_str(), ToString(availRect).c_str(), pixelDepth,
+           refreshRate, contentsScaleFactor.scale, defaultCssScaleFactor.scale,
+           dpi, isPseudoDisplay, uint32_t(orientation), angle));
+  auto screen = MakeRefPtr<Screen>(
+      rect, availRect, pixelDepth, pixelDepth, refreshRate, contentsScaleFactor,
+      defaultCssScaleFactor, dpi, Screen::IsPseudoDisplay(isPseudoDisplay),
+      orientation, angle);
+  if (info.dwFlags & MONITORINFOF_PRIMARY) {
+    // The primary monitor must be the first element of the screen list.
+    screens->InsertElementAt(0, std::move(screen));
+  } else {
+    screens->AppendElement(std::move(screen));
+  }
+  return TRUE;
+}
+
+void ScreenHelperWin::RefreshScreens() {
+  MOZ_LOG(sScreenLog, LogLevel::Debug, ("Refreshing screens"));
+
+  AutoTArray<RefPtr<Screen>, 4> screens;
+  BOOL result = ::EnumDisplayMonitors(
+      nullptr, nullptr, (MONITORENUMPROC)CollectMonitors, (LPARAM)&screens);
+  if (!result) {
+    NS_WARNING("Unable to EnumDisplayMonitors");
+  }
+  ScreenManager::Refresh(std::move(screens));
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/ScreenHelperWin.h b/widget/windows/ScreenHelperWin.h
new file mode 100644
index 0000000000..275014232a
--- /dev/null
+++ b/widget/windows/ScreenHelperWin.h
@@ -0,0 +1,26 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_windows_ScreenHelperWin_h
+#define mozilla_widget_windows_ScreenHelperWin_h
+
+#include "mozilla/widget/ScreenManager.h"
+
+namespace mozilla {
+namespace widget {
+
+class ScreenHelperWin final : public ScreenManager::Helper {
+ public:
+  ScreenHelperWin(){};
+  ~ScreenHelperWin() override {}
+
+  static void RefreshScreens();
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_windows_ScreenHelperWin_h
diff --git a/widget/windows/ShellHeaderOnlyUtils.h b/widget/windows/ShellHeaderOnlyUtils.h
new file mode 100644
index 0000000000..ea95077fb3
--- /dev/null
+++ b/widget/windows/ShellHeaderOnlyUtils.h
@@ -0,0 +1,183 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ShellHeaderOnlyUtils_h
+#define mozilla_ShellHeaderOnlyUtils_h
+
+#if defined(LIBXUL) && !defined(UNICODE)
+#  error \
+      "UNICODE not set - must be set to prevent compile failure in `comdef.h` due to us deleting `FormatMessage` when absent."
+#endif
+
+#include "mozilla/WinHeaderOnlyUtils.h"
+
+#include <objbase.h>
+
+#include <exdisp.h>
+#include <shldisp.h>
+#include <shlobj.h>
+#include <shlwapi.h>
+#include <shobjidl.h>
+#include <shtypes.h>
+// NB: include this after shldisp.h so its macros do not conflict with COM
+// interfaces defined by shldisp.h
+#include <shellapi.h>
+#include <type_traits>
+
+#include <comdef.h>
+#include <comutil.h>
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
+
+namespace mozilla {
+
+/**
+ * Ask the current user's Desktop to ShellExecute on our behalf, thus causing
+ * the resulting launched process to inherit its security priviliges from
+ * Explorer instead of our process.
+ *
+ * This is useful in two scenarios, in particular:
+ *   * We are running as an elevated user and we want to start something as the
+ *     "normal" user;
+ *   * We are starting a process that is incompatible with our process's
+ *     process mitigation policies. By delegating to Explorer, the child process
+ *     will not be affected by our process mitigations.
+ *
+ * Since this communication happens over DCOM, Explorer's COM DACL governs
+ * whether or not we can execute against it, thus avoiding privilege escalation.
+ */
+inline LauncherVoidResult ShellExecuteByExplorer(const _bstr_t& aPath,
+                                                 const _variant_t& aArgs,
+                                                 const _variant_t& aVerb,
+                                                 const _variant_t& aWorkingDir,
+                                                 const _variant_t& aShowCmd) {
+  // NB: Explorer may be a local server, not an inproc server
+  RefPtr<IShellWindows> shellWindows;
+  HRESULT hr = ::CoCreateInstance(
+      CLSID_ShellWindows, nullptr, CLSCTX_INPROC_SERVER | CLSCTX_LOCAL_SERVER,
+      IID_IShellWindows, getter_AddRefs(shellWindows));
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  // 1. Find the shell view for the desktop.
+  _variant_t loc(int(CSIDL_DESKTOP));
+  _variant_t empty;
+  long hwnd;
+  RefPtr<IDispatch> dispDesktop;
+  hr = shellWindows->FindWindowSW(&loc, &empty, SWC_DESKTOP, &hwnd,
+                                  SWFO_NEEDDISPATCH,
+                                  getter_AddRefs(dispDesktop));
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  if (hr == S_FALSE) {
+    // The call succeeded but the window was not found.
+    return LAUNCHER_ERROR_FROM_WIN32(ERROR_NOT_FOUND);
+  }
+
+  RefPtr<IServiceProvider> servProv;
+  hr = dispDesktop->QueryInterface(IID_IServiceProvider,
+                                   getter_AddRefs(servProv));
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  RefPtr<IShellBrowser> browser;
+  hr = servProv->QueryService(SID_STopLevelBrowser, IID_IShellBrowser,
+                              getter_AddRefs(browser));
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  RefPtr<IShellView> activeShellView;
+  hr = browser->QueryActiveShellView(getter_AddRefs(activeShellView));
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  // 2. Get the automation object for the desktop.
+  RefPtr<IDispatch> dispView;
+  hr = activeShellView->GetItemObject(SVGIO_BACKGROUND, IID_IDispatch,
+                                      getter_AddRefs(dispView));
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  RefPtr<IShellFolderViewDual> folderView;
+  hr = dispView->QueryInterface(IID_IShellFolderViewDual,
+                                getter_AddRefs(folderView));
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  // 3. Get the interface to IShellDispatch2
+  RefPtr<IDispatch> dispShell;
+  hr = folderView->get_Application(getter_AddRefs(dispShell));
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  RefPtr<IShellDispatch2> shellDisp;
+  hr =
+      dispShell->QueryInterface(IID_IShellDispatch2, getter_AddRefs(shellDisp));
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  // Passing the foreground privilege so that the shell can launch an
+  // application in the foreground.  This fails with E_ACCESSDENIED if the
+  // current window is shown in the background.  We keep a soft assert for
+  // the other failures to investigate how it happened.
+  hr = ::CoAllowSetForegroundWindow(shellDisp, nullptr);
+  MOZ_ASSERT(SUCCEEDED(hr) || hr == E_ACCESSDENIED);
+
+  // shellapi.h macros interfere with the correct naming of the method being
+  // called on IShellDispatch2. Temporarily remove that definition.
+#if defined(ShellExecute)
+#  define MOZ_REDEFINE_SHELLEXECUTE
+#  undef ShellExecute
+#endif  // defined(ShellExecute)
+
+  // 4. Now call IShellDispatch2::ShellExecute to ask Explorer to execute.
+  hr = shellDisp->ShellExecute(aPath, aArgs, aWorkingDir, aVerb, aShowCmd);
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  // Restore the macro that was removed prior to IShellDispatch2::ShellExecute
+#if defined(MOZ_REDEFINE_SHELLEXECUTE)
+#  if defined(UNICODE)
+#    define ShellExecute ShellExecuteW
+#  else
+#    define ShellExecute ShellExecuteA
+#  endif
+#  undef MOZ_REDEFINE_SHELLEXECUTE
+#endif  // defined(MOZ_REDEFINE_SHELLEXECUTE)
+
+  return Ok();
+}
+
+using UniqueAbsolutePidl =
+    UniquePtr<std::remove_pointer_t<PIDLIST_ABSOLUTE>, CoTaskMemFreeDeleter>;
+
+inline LauncherResult<UniqueAbsolutePidl> ShellParseDisplayName(
+    const wchar_t* aPath) {
+  PIDLIST_ABSOLUTE rawAbsPidl = nullptr;
+  SFGAOF sfgao;
+  HRESULT hr = ::SHParseDisplayName(aPath, nullptr, &rawAbsPidl, 0, &sfgao);
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  return UniqueAbsolutePidl(rawAbsPidl);
+}
+
+}  // namespace mozilla
+
+#endif  // mozilla_ShellHeaderOnlyUtils_h
diff --git a/widget/windows/SystemStatusBar.cpp b/widget/windows/SystemStatusBar.cpp
new file mode 100644
index 0000000000..6cc5668bbe
--- /dev/null
+++ b/widget/windows/SystemStatusBar.cpp
@@ -0,0 +1,339 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <strsafe.h>
+#include "SystemStatusBar.h"
+
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/EventDispatcher.h"
+#include "mozilla/LinkedList.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/widget/IconLoader.h"
+#include "mozilla/dom/XULButtonElement.h"
+#include "nsComputedDOMStyle.h"
+#include "nsIContentPolicy.h"
+#include "nsISupports.h"
+#include "nsMenuPopupFrame.h"
+#include "nsXULPopupManager.h"
+#include "nsIDocShell.h"
+#include "nsDocShell.h"
+#include "nsWindowGfx.h"
+
+#include "shellapi.h"
+
+namespace mozilla::widget {
+
+using mozilla::LinkedListElement;
+using mozilla::dom::Element;
+
+class StatusBarEntry final : public LinkedListElement<RefPtr<StatusBarEntry>>,
+                             public IconLoader::Listener,
+                             public nsISupports {
+ public:
+  explicit StatusBarEntry(Element* aMenu);
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS(StatusBarEntry)
+  nsresult Init();
+  void Destroy();
+
+  MOZ_CAN_RUN_SCRIPT LRESULT OnMessage(HWND hWnd, UINT msg, WPARAM wp,
+                                       LPARAM lp);
+  const Element* GetMenu() { return mMenu; };
+
+  nsresult OnComplete(imgIContainer* aImage) override;
+
+ private:
+  ~StatusBarEntry();
+  RefPtr<mozilla::widget::IconLoader> mIconLoader;
+  // Effectively const but is cycle collected
+  MOZ_KNOWN_LIVE RefPtr<Element> mMenu;
+  NOTIFYICONDATAW mIconData;
+  boolean mInitted;
+};
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(StatusBarEntry)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(StatusBarEntry)
+  tmp->Destroy();
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(StatusBarEntry)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mIconLoader)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mMenu)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(StatusBarEntry)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(StatusBarEntry)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(StatusBarEntry)
+
+StatusBarEntry::StatusBarEntry(Element* aMenu) : mMenu(aMenu), mInitted(false) {
+  mIconData = {/* cbSize */ sizeof(NOTIFYICONDATA),
+               /* hWnd */ 0,
+               /* uID */ 2,
+               /* uFlags */ NIF_ICON | NIF_MESSAGE | NIF_TIP | NIF_SHOWTIP,
+               /* uCallbackMessage */ WM_USER,
+               /* hIcon */ 0,
+               /* szTip */ L"",  // This is updated in Init()
+               /* dwState */ 0,
+               /* dwStateMask */ 0,
+               /* szInfo */ L"",
+               /* uVersion */ {NOTIFYICON_VERSION_4},
+               /* szInfoTitle */ L"",
+               /* dwInfoFlags */ 0};
+  MOZ_ASSERT(mMenu);
+}
+
+StatusBarEntry::~StatusBarEntry() {
+  if (!mInitted) {
+    return;
+  }
+  Destroy();
+  ::Shell_NotifyIconW(NIM_DELETE, &mIconData);
+  VERIFY(::DestroyWindow(mIconData.hWnd));
+}
+
+void StatusBarEntry::Destroy() {
+  if (mIconLoader) {
+    mIconLoader->Destroy();
+    mIconLoader = nullptr;
+  }
+}
+
+nsresult StatusBarEntry::Init() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // First, look at the content node's "image" attribute.
+  nsAutoString imageURIString;
+  bool hasImageAttr = mMenu->GetAttr(nsGkAtoms::image, imageURIString);
+
+  nsresult rv;
+  nsCOMPtr<nsIURI> iconURI;
+  if (!hasImageAttr) {
+    // If the content node has no "image" attribute, get the
+    // "list-style-image" property from CSS.
+    RefPtr<mozilla::dom::Document> document = mMenu->GetComposedDoc();
+    if (!document) {
+      return NS_ERROR_FAILURE;
+    }
+
+    RefPtr<const ComputedStyle> sc =
+        nsComputedDOMStyle::GetComputedStyle(mMenu);
+    if (!sc) {
+      return NS_ERROR_FAILURE;
+    }
+
+    iconURI = sc->StyleList()->GetListStyleImageURI();
+  } else {
+    uint64_t dummy = 0;
+    nsContentPolicyType policyType;
+    nsCOMPtr<nsIPrincipal> triggeringPrincipal = mMenu->NodePrincipal();
+    nsContentUtils::GetContentPolicyTypeForUIImageLoading(
+        mMenu, getter_AddRefs(triggeringPrincipal), policyType, &dummy);
+    if (policyType != nsIContentPolicy::TYPE_INTERNAL_IMAGE) {
+      return NS_ERROR_ILLEGAL_VALUE;
+    }
+
+    // If this menu item shouldn't have an icon, the string will be empty,
+    // and NS_NewURI will fail.
+    rv = NS_NewURI(getter_AddRefs(iconURI), imageURIString);
+    if (NS_FAILED(rv)) return rv;
+  }
+
+  mIconLoader = new IconLoader(this);
+
+  if (iconURI) {
+    rv = mIconLoader->LoadIcon(iconURI, mMenu);
+  }
+
+  HWND iconWindow;
+  NS_ENSURE_TRUE(iconWindow = ::CreateWindowExW(
+                     /* extended style */ 0,
+                     /* className */ L"IconWindowClass",
+                     /* title */ 0,
+                     /* style */ WS_CAPTION,
+                     /* x, y, cx, cy */ 0, 0, 0, 0,
+                     /* parent */ 0,
+                     /* menu */ 0,
+                     /* instance */ 0,
+                     /* create struct */ 0),
+                 NS_ERROR_FAILURE);
+  ::SetWindowLongPtr(iconWindow, GWLP_USERDATA, (LONG_PTR)this);
+
+  mIconData.hWnd = iconWindow;
+  mIconData.hIcon = ::LoadIcon(::GetModuleHandle(NULL), IDI_APPLICATION);
+
+  nsAutoString labelAttr;
+  mMenu->GetAttr(nsGkAtoms::label, labelAttr);
+  const nsString& label = PromiseFlatString(labelAttr);
+
+  size_t destLength = sizeof mIconData.szTip / (sizeof mIconData.szTip[0]);
+  wchar_t* tooltip = &(mIconData.szTip[0]);
+  ::StringCchCopyNW(tooltip, destLength, label.get(), label.Length());
+
+  ::Shell_NotifyIconW(NIM_ADD, &mIconData);
+  ::Shell_NotifyIconW(NIM_SETVERSION, &mIconData);
+
+  mInitted = true;
+  return NS_OK;
+}
+
+nsresult StatusBarEntry::OnComplete(imgIContainer* aImage) {
+  NS_ENSURE_ARG_POINTER(aImage);
+
+  RefPtr<StatusBarEntry> kungFuDeathGrip = this;
+
+  nsresult rv = nsWindowGfx::CreateIcon(
+      aImage, false, LayoutDeviceIntPoint(),
+      nsWindowGfx::GetIconMetrics(nsWindowGfx::kRegularIcon), &mIconData.hIcon);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  ::Shell_NotifyIconW(NIM_MODIFY, &mIconData);
+
+  if (mIconData.hIcon) {
+    ::DestroyIcon(mIconData.hIcon);
+    mIconData.hIcon = nullptr;
+  }
+
+  // To simplify things, we won't react to CSS changes to update the icon
+  // with this implementation. We can get rid of the IconLoader at this point.
+  mIconLoader->Destroy();
+  mIconLoader = nullptr;
+  return NS_OK;
+}
+
+LRESULT StatusBarEntry::OnMessage(HWND hWnd, UINT msg, WPARAM wp, LPARAM lp) {
+  if (msg == WM_USER &&
+      (LOWORD(lp) == NIN_SELECT || LOWORD(lp) == NIN_KEYSELECT ||
+       LOWORD(lp) == WM_CONTEXTMENU)) {
+    auto* menu = dom::XULButtonElement::FromNode(mMenu);
+    if (!menu) {
+      return TRUE;
+    }
+
+    nsMenuPopupFrame* popupFrame = menu->GetMenuPopup(FlushType::None);
+    if (NS_WARN_IF(!popupFrame)) {
+      return TRUE;
+    }
+
+    nsIWidget* widget = popupFrame->GetNearestWidget();
+    MOZ_DIAGNOSTIC_ASSERT(widget);
+    if (!widget) {
+      return TRUE;
+    }
+
+    HWND win = static_cast<HWND>(widget->GetNativeData(NS_NATIVE_WINDOW));
+    MOZ_DIAGNOSTIC_ASSERT(win);
+    if (!win) {
+      return TRUE;
+    }
+
+    if (LOWORD(lp) == NIN_KEYSELECT && ::GetForegroundWindow() == win) {
+      // When enter is pressed on the icon, the shell sends two NIN_KEYSELECT
+      // notifications. This might cause us to open two windows. To work around
+      // this, if we're already the foreground window (which happens below),
+      // ignore this notification.
+      return TRUE;
+    }
+
+    if (LOWORD(lp) != WM_CONTEXTMENU &&
+        mMenu->HasAttr(nsGkAtoms::contextmenu)) {
+      ::SetForegroundWindow(win);
+      nsEventStatus status = nsEventStatus_eIgnore;
+      WidgetMouseEvent event(true, eXULSystemStatusBarClick, nullptr,
+                             WidgetMouseEvent::eReal);
+      RefPtr<nsPresContext> presContext = popupFrame->PresContext();
+      EventDispatcher::Dispatch(mMenu, presContext, &event, nullptr, &status);
+      return DefWindowProc(hWnd, msg, wp, lp);
+    }
+
+    nsPresContext* pc = popupFrame->PresContext();
+    const CSSIntPoint point = gfx::RoundedToInt(
+        LayoutDeviceIntPoint(GET_X_LPARAM(wp), GET_Y_LPARAM(wp)) /
+        pc->CSSToDevPixelScale());
+
+    // The menu that is being opened is a Gecko <xul:menu>, and the popup code
+    // that manages it expects that the window that the <xul:menu> belongs to
+    // will be in the foreground when it opens. If we don't do this, then if the
+    // icon is clicked when the window is _not_ in the foreground, then the
+    // opened menu will not be keyboard focusable, nor will it close on its own
+    // if the user clicks away from the menu (at least, not until the user
+    // focuses any window in the parent process).
+    ::SetForegroundWindow(win);
+    nsXULPopupManager* pm = nsXULPopupManager::GetInstance();
+    pm->ShowPopupAtScreen(popupFrame->GetContent()->AsElement(), point.x,
+                          point.y, false, nullptr);
+  }
+
+  return DefWindowProc(hWnd, msg, wp, lp);
+}
+
+NS_IMPL_ISUPPORTS(SystemStatusBar, nsISystemStatusBar)
+
+MOZ_CAN_RUN_SCRIPT static LRESULT CALLBACK WindowProc(HWND hWnd, UINT msg,
+                                                      WPARAM wp, LPARAM lp) {
+  if (RefPtr<StatusBarEntry> entry =
+          (StatusBarEntry*)GetWindowLongPtr(hWnd, GWLP_USERDATA)) {
+    return entry->OnMessage(hWnd, msg, wp, lp);
+  }
+  return TRUE;
+}
+
+static StaticRefPtr<SystemStatusBar> sSingleton;
+
+SystemStatusBar& SystemStatusBar::GetSingleton() {
+  if (!sSingleton) {
+    sSingleton = new SystemStatusBar();
+    ClearOnShutdown(&sSingleton);
+  }
+  return *sSingleton;
+}
+
+already_AddRefed<SystemStatusBar> SystemStatusBar::GetAddRefedSingleton() {
+  RefPtr<SystemStatusBar> sm = &GetSingleton();
+  return sm.forget();
+}
+
+nsresult SystemStatusBar::Init() {
+  WNDCLASS classStruct = {/* style */ 0,
+                          /* lpfnWndProc */ &WindowProc,
+                          /* cbClsExtra */ 0,
+                          /* cbWndExtra */ 0,
+                          /* hInstance */ 0,
+                          /* hIcon */ 0,
+                          /* hCursor */ 0,
+                          /* hbrBackground */ 0,
+                          /* lpszMenuName */ 0,
+                          /* lpszClassName */ L"IconWindowClass"};
+  NS_ENSURE_TRUE(::RegisterClass(&classStruct), NS_ERROR_FAILURE);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+SystemStatusBar::AddItem(Element* aElement) {
+  RefPtr<StatusBarEntry> entry = new StatusBarEntry(aElement);
+  nsresult rv = entry->Init();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mStatusBarEntries.insertBack(entry);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+SystemStatusBar::RemoveItem(Element* aElement) {
+  for (StatusBarEntry* entry : mStatusBarEntries) {
+    if (entry->GetMenu() == aElement) {
+      entry->removeFrom(mStatusBarEntries);
+      return NS_OK;
+    }
+  }
+  return NS_ERROR_NOT_AVAILABLE;
+}
+
+}  // namespace mozilla::widget
diff --git a/widget/windows/SystemStatusBar.h b/widget/windows/SystemStatusBar.h
new file mode 100644
index 0000000000..6afafd9d80
--- /dev/null
+++ b/widget/windows/SystemStatusBar.h
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_SystemStatusBar_h
+#define widget_windows_SystemStatusBar_h
+
+#include "nsISystemStatusBar.h"
+#include "mozilla/LinkedList.h"
+
+namespace mozilla::widget {
+class StatusBarEntry;
+
+class SystemStatusBar final : public nsISystemStatusBar {
+ public:
+  explicit SystemStatusBar() = default;
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISYSTEMSTATUSBAR
+
+  static SystemStatusBar& GetSingleton();
+  static already_AddRefed<SystemStatusBar> GetAddRefedSingleton();
+
+  nsresult Init();
+
+ private:
+  ~SystemStatusBar() = default;
+  mozilla::LinkedList<RefPtr<StatusBarEntry>> mStatusBarEntries;
+};
+
+}  // namespace mozilla::widget
+
+#endif  // widget_windows_SystemStatusBar_h
diff --git a/widget/windows/TSFTextStore.cpp b/widget/windows/TSFTextStore.cpp
new file mode 100644
index 0000000000..b3e3a164ae
--- /dev/null
+++ b/widget/windows/TSFTextStore.cpp
@@ -0,0 +1,7513 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#define INPUTSCOPE_INIT_GUID
+#define TEXTATTRS_INIT_GUID
+#include "TSFTextStore.h"
+
+#include <algorithm>
+#include <comutil.h>  // for _bstr_t
+#include <oleauto.h>  // for SysAllocString
+#include <olectl.h>
+#include "nscore.h"
+
+#include "IMMHandler.h"
+#include "KeyboardLayout.h"
+#include "WinIMEHandler.h"
+#include "WinUtils.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/Logging.h"
+#include "mozilla/StaticPrefs_intl.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/ToString.h"
+#include "mozilla/WindowsVersion.h"
+#include "mozilla/widget/WinRegistry.h"
+#include "nsWindow.h"
+#include "nsPrintfCString.h"
+
+// For collecting other people's log, tell `MOZ_LOG=IMEHandler:4,sync`
+// rather than `MOZ_LOG=IMEHandler:5,sync` since using `5` may create too
+// big file.
+// Therefore you shouldn't use `LogLevel::Verbose` for logging usual behavior.
+mozilla::LazyLogModule gIMELog("IMEHandler");
+
+// TODO: GUID_PROP_URL has not been declared in the SDK yet.  We should drop the
+//       `s` prefix after it's released by a new SDK and define it with #if.
+static const GUID sGUID_PROP_URL = {
+    0xd5138268,
+    0xa1bf,
+    0x4308,
+    {0xbc, 0xbf, 0x2e, 0x73, 0x93, 0x98, 0xe2, 0x34}};
+
+namespace mozilla {
+namespace widget {
+
+/**
+ * TSF related code should log its behavior even on release build especially
+ * in the interface methods.
+ *
+ * In interface methods, use LogLevel::Info.
+ * In internal methods, use LogLevel::Debug for logging normal behavior.
+ * For logging error, use LogLevel::Error.
+ *
+ * When an instance method is called, start with following text:
+ *   "0x%p TSFFoo::Bar(", the 0x%p should be the "this" of the nsFoo.
+ * after that, start with:
+ *   "0x%p   TSFFoo::Bar("
+ * In an internal method, start with following text:
+ *   "0x%p   TSFFoo::Bar("
+ * When a static method is called, start with following text:
+ *   "TSFFoo::Bar("
+ */
+
+enum class TextInputProcessorID {
+  // Internal use only.  This won't be returned by TSFStaticSink::ActiveTIP().
+  eNotComputed,
+
+  // Not a TIP.  E.g., simple keyboard layout or IMM-IME.
+  eNone,
+
+  // Used for other TIPs, i.e., any TIPs which we don't support specifically.
+  eUnknown,
+
+  // TIP for Japanese.
+  eMicrosoftIMEForJapanese,
+  eMicrosoftOfficeIME2010ForJapanese,
+  eGoogleJapaneseInput,
+  eATOK2011,
+  eATOK2012,
+  eATOK2013,
+  eATOK2014,
+  eATOK2015,
+  eATOK2016,
+  eATOKUnknown,
+  eJapanist10,
+
+  // TIP for Traditional Chinese.
+  eMicrosoftBopomofo,
+  eMicrosoftChangJie,
+  eMicrosoftPhonetic,
+  eMicrosoftQuick,
+  eMicrosoftNewChangJie,
+  eMicrosoftNewPhonetic,
+  eMicrosoftNewQuick,
+  eFreeChangJie,
+
+  // TIP for Simplified Chinese.
+  eMicrosoftPinyin,
+  eMicrosoftPinyinNewExperienceInputStyle,
+  eMicrosoftWubi,
+
+  // TIP for Korean.
+  eMicrosoftIMEForKorean,
+  eMicrosoftOldHangul,
+
+  // Keyman Desktop, which can install various language keyboards.
+  eKeymanDesktop,
+};
+
+static const char* GetBoolName(bool aBool) { return aBool ? "true" : "false"; }
+
+static void HandleSeparator(nsCString& aDesc) {
+  if (!aDesc.IsEmpty()) {
+    aDesc.AppendLiteral(" | ");
+  }
+}
+
+static const nsCString GetFindFlagName(DWORD aFindFlag) {
+  nsCString description;
+  if (!aFindFlag) {
+    description.AppendLiteral("no flags (0)");
+    return description;
+  }
+  if (aFindFlag & TS_ATTR_FIND_BACKWARDS) {
+    description.AppendLiteral("TS_ATTR_FIND_BACKWARDS");
+  }
+  if (aFindFlag & TS_ATTR_FIND_WANT_OFFSET) {
+    HandleSeparator(description);
+    description.AppendLiteral("TS_ATTR_FIND_WANT_OFFSET");
+  }
+  if (aFindFlag & TS_ATTR_FIND_UPDATESTART) {
+    HandleSeparator(description);
+    description.AppendLiteral("TS_ATTR_FIND_UPDATESTART");
+  }
+  if (aFindFlag & TS_ATTR_FIND_WANT_VALUE) {
+    HandleSeparator(description);
+    description.AppendLiteral("TS_ATTR_FIND_WANT_VALUE");
+  }
+  if (aFindFlag & TS_ATTR_FIND_WANT_END) {
+    HandleSeparator(description);
+    description.AppendLiteral("TS_ATTR_FIND_WANT_END");
+  }
+  if (aFindFlag & TS_ATTR_FIND_HIDDEN) {
+    HandleSeparator(description);
+    description.AppendLiteral("TS_ATTR_FIND_HIDDEN");
+  }
+  if (description.IsEmpty()) {
+    description.AppendLiteral("Unknown (");
+    description.AppendInt(static_cast<uint32_t>(aFindFlag));
+    description.Append(')');
+  }
+  return description;
+}
+
+class GetACPFromPointFlagName : public nsAutoCString {
+ public:
+  explicit GetACPFromPointFlagName(DWORD aFlags) {
+    if (!aFlags) {
+      AppendLiteral("no flags (0)");
+      return;
+    }
+    if (aFlags & GXFPF_ROUND_NEAREST) {
+      AppendLiteral("GXFPF_ROUND_NEAREST");
+      aFlags &= ~GXFPF_ROUND_NEAREST;
+    }
+    if (aFlags & GXFPF_NEAREST) {
+      HandleSeparator(*this);
+      AppendLiteral("GXFPF_NEAREST");
+      aFlags &= ~GXFPF_NEAREST;
+    }
+    if (aFlags) {
+      HandleSeparator(*this);
+      AppendLiteral("Unknown(");
+      AppendInt(static_cast<uint32_t>(aFlags));
+      Append(')');
+    }
+  }
+  virtual ~GetACPFromPointFlagName() {}
+};
+
+static const char* GetFocusChangeName(
+    InputContextAction::FocusChange aFocusChange) {
+  switch (aFocusChange) {
+    case InputContextAction::FOCUS_NOT_CHANGED:
+      return "FOCUS_NOT_CHANGED";
+    case InputContextAction::GOT_FOCUS:
+      return "GOT_FOCUS";
+    case InputContextAction::LOST_FOCUS:
+      return "LOST_FOCUS";
+    case InputContextAction::MENU_GOT_PSEUDO_FOCUS:
+      return "MENU_GOT_PSEUDO_FOCUS";
+    case InputContextAction::MENU_LOST_PSEUDO_FOCUS:
+      return "MENU_LOST_PSEUDO_FOCUS";
+    case InputContextAction::WIDGET_CREATED:
+      return "WIDGET_CREATED";
+    default:
+      return "Unknown";
+  }
+}
+
+static nsCString GetCLSIDNameStr(REFCLSID aCLSID) {
+  LPOLESTR str = nullptr;
+  HRESULT hr = ::StringFromCLSID(aCLSID, &str);
+  if (FAILED(hr) || !str || !str[0]) {
+    return ""_ns;
+  }
+
+  nsCString result;
+  result = NS_ConvertUTF16toUTF8(str);
+  ::CoTaskMemFree(str);
+  return result;
+}
+
+static nsCString GetGUIDNameStr(REFGUID aGUID) {
+  OLECHAR str[40];
+  int len = ::StringFromGUID2(aGUID, str, ArrayLength(str));
+  if (!len || !str[0]) {
+    return ""_ns;
+  }
+
+  return NS_ConvertUTF16toUTF8(str);
+}
+
+static nsCString GetGUIDNameStrWithTable(REFGUID aGUID) {
+#define RETURN_GUID_NAME(aNamedGUID)      \
+  if (IsEqualGUID(aGUID, aNamedGUID)) {   \
+    return nsLiteralCString(#aNamedGUID); \
+  }
+
+  RETURN_GUID_NAME(GUID_PROP_INPUTSCOPE)
+  RETURN_GUID_NAME(sGUID_PROP_URL)
+  RETURN_GUID_NAME(TSATTRID_OTHERS)
+  RETURN_GUID_NAME(TSATTRID_Font)
+  RETURN_GUID_NAME(TSATTRID_Font_FaceName)
+  RETURN_GUID_NAME(TSATTRID_Font_SizePts)
+  RETURN_GUID_NAME(TSATTRID_Font_Style)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Bold)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Italic)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_SmallCaps)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Capitalize)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Uppercase)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Lowercase)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Animation)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Animation_LasVegasLights)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Animation_BlinkingBackground)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Animation_SparkleText)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Animation_MarchingBlackAnts)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Animation_MarchingRedAnts)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Animation_Shimmer)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Animation_WipeDown)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Animation_WipeRight)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Emboss)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Engrave)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Hidden)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Kerning)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Outlined)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Position)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Protected)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Shadow)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Spacing)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Weight)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Height)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Underline)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Underline_Single)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Underline_Double)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Strikethrough)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Strikethrough_Single)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Strikethrough_Double)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Overline)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Overline_Single)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Overline_Double)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Blink)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Subscript)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Superscript)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_Color)
+  RETURN_GUID_NAME(TSATTRID_Font_Style_BackgroundColor)
+  RETURN_GUID_NAME(TSATTRID_Text)
+  RETURN_GUID_NAME(TSATTRID_Text_VerticalWriting)
+  RETURN_GUID_NAME(TSATTRID_Text_RightToLeft)
+  RETURN_GUID_NAME(TSATTRID_Text_Orientation)
+  RETURN_GUID_NAME(TSATTRID_Text_Language)
+  RETURN_GUID_NAME(TSATTRID_Text_ReadOnly)
+  RETURN_GUID_NAME(TSATTRID_Text_EmbeddedObject)
+  RETURN_GUID_NAME(TSATTRID_Text_Alignment)
+  RETURN_GUID_NAME(TSATTRID_Text_Alignment_Left)
+  RETURN_GUID_NAME(TSATTRID_Text_Alignment_Right)
+  RETURN_GUID_NAME(TSATTRID_Text_Alignment_Center)
+  RETURN_GUID_NAME(TSATTRID_Text_Alignment_Justify)
+  RETURN_GUID_NAME(TSATTRID_Text_Link)
+  RETURN_GUID_NAME(TSATTRID_Text_Hyphenation)
+  RETURN_GUID_NAME(TSATTRID_Text_Para)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_FirstLineIndent)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_LeftIndent)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_RightIndent)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_SpaceAfter)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_SpaceBefore)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_LineSpacing)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_LineSpacing_Single)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_LineSpacing_OnePtFive)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_LineSpacing_Double)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_LineSpacing_AtLeast)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_LineSpacing_Exactly)
+  RETURN_GUID_NAME(TSATTRID_Text_Para_LineSpacing_Multiple)
+  RETURN_GUID_NAME(TSATTRID_List)
+  RETURN_GUID_NAME(TSATTRID_List_LevelIndel)
+  RETURN_GUID_NAME(TSATTRID_List_Type)
+  RETURN_GUID_NAME(TSATTRID_List_Type_Bullet)
+  RETURN_GUID_NAME(TSATTRID_List_Type_Arabic)
+  RETURN_GUID_NAME(TSATTRID_List_Type_LowerLetter)
+  RETURN_GUID_NAME(TSATTRID_List_Type_UpperLetter)
+  RETURN_GUID_NAME(TSATTRID_List_Type_LowerRoman)
+  RETURN_GUID_NAME(TSATTRID_List_Type_UpperRoman)
+  RETURN_GUID_NAME(TSATTRID_App)
+  RETURN_GUID_NAME(TSATTRID_App_IncorrectSpelling)
+  RETURN_GUID_NAME(TSATTRID_App_IncorrectGrammar)
+
+#undef RETURN_GUID_NAME
+
+  return GetGUIDNameStr(aGUID);
+}
+
+static nsCString GetRIIDNameStr(REFIID aRIID) {
+  LPOLESTR str = nullptr;
+  HRESULT hr = ::StringFromIID(aRIID, &str);
+  if (FAILED(hr) || !str || !str[0]) {
+    return ""_ns;
+  }
+
+  nsAutoString key(L"Interface\\");
+  key += str;
+
+  nsCString result;
+  wchar_t buf[256];
+  if (WinRegistry::GetString(HKEY_CLASSES_ROOT, key, u""_ns, buf,
+                             WinRegistry::kLegacyWinUtilsStringFlags)) {
+    result = NS_ConvertUTF16toUTF8(buf);
+  } else {
+    result = NS_ConvertUTF16toUTF8(str);
+  }
+
+  ::CoTaskMemFree(str);
+  return result;
+}
+
+static const char* GetCommonReturnValueName(HRESULT aResult) {
+  switch (aResult) {
+    case S_OK:
+      return "S_OK";
+    case E_ABORT:
+      return "E_ABORT";
+    case E_ACCESSDENIED:
+      return "E_ACCESSDENIED";
+    case E_FAIL:
+      return "E_FAIL";
+    case E_HANDLE:
+      return "E_HANDLE";
+    case E_INVALIDARG:
+      return "E_INVALIDARG";
+    case E_NOINTERFACE:
+      return "E_NOINTERFACE";
+    case E_NOTIMPL:
+      return "E_NOTIMPL";
+    case E_OUTOFMEMORY:
+      return "E_OUTOFMEMORY";
+    case E_POINTER:
+      return "E_POINTER";
+    case E_UNEXPECTED:
+      return "E_UNEXPECTED";
+    default:
+      return SUCCEEDED(aResult) ? "Succeeded" : "Failed";
+  }
+}
+
+static const char* GetTextStoreReturnValueName(HRESULT aResult) {
+  switch (aResult) {
+    case TS_E_FORMAT:
+      return "TS_E_FORMAT";
+    case TS_E_INVALIDPOINT:
+      return "TS_E_INVALIDPOINT";
+    case TS_E_INVALIDPOS:
+      return "TS_E_INVALIDPOS";
+    case TS_E_NOINTERFACE:
+      return "TS_E_NOINTERFACE";
+    case TS_E_NOLAYOUT:
+      return "TS_E_NOLAYOUT";
+    case TS_E_NOLOCK:
+      return "TS_E_NOLOCK";
+    case TS_E_NOOBJECT:
+      return "TS_E_NOOBJECT";
+    case TS_E_NOSELECTION:
+      return "TS_E_NOSELECTION";
+    case TS_E_NOSERVICE:
+      return "TS_E_NOSERVICE";
+    case TS_E_READONLY:
+      return "TS_E_READONLY";
+    case TS_E_SYNCHRONOUS:
+      return "TS_E_SYNCHRONOUS";
+    case TS_S_ASYNC:
+      return "TS_S_ASYNC";
+    default:
+      return GetCommonReturnValueName(aResult);
+  }
+}
+
+static const nsCString GetSinkMaskNameStr(DWORD aSinkMask) {
+  nsCString description;
+  if (aSinkMask & TS_AS_TEXT_CHANGE) {
+    description.AppendLiteral("TS_AS_TEXT_CHANGE");
+  }
+  if (aSinkMask & TS_AS_SEL_CHANGE) {
+    HandleSeparator(description);
+    description.AppendLiteral("TS_AS_SEL_CHANGE");
+  }
+  if (aSinkMask & TS_AS_LAYOUT_CHANGE) {
+    HandleSeparator(description);
+    description.AppendLiteral("TS_AS_LAYOUT_CHANGE");
+  }
+  if (aSinkMask & TS_AS_ATTR_CHANGE) {
+    HandleSeparator(description);
+    description.AppendLiteral("TS_AS_ATTR_CHANGE");
+  }
+  if (aSinkMask & TS_AS_STATUS_CHANGE) {
+    HandleSeparator(description);
+    description.AppendLiteral("TS_AS_STATUS_CHANGE");
+  }
+  if (description.IsEmpty()) {
+    description.AppendLiteral("not-specified");
+  }
+  return description;
+}
+
+static const nsCString GetLockFlagNameStr(DWORD aLockFlags) {
+  nsCString description;
+  if ((aLockFlags & TS_LF_READWRITE) == TS_LF_READWRITE) {
+    description.AppendLiteral("TS_LF_READWRITE");
+  } else if (aLockFlags & TS_LF_READ) {
+    description.AppendLiteral("TS_LF_READ");
+  }
+  if (aLockFlags & TS_LF_SYNC) {
+    if (!description.IsEmpty()) {
+      description.AppendLiteral(" | ");
+    }
+    description.AppendLiteral("TS_LF_SYNC");
+  }
+  if (description.IsEmpty()) {
+    description.AppendLiteral("not-specified");
+  }
+  return description;
+}
+
+static const char* GetTextRunTypeName(TsRunType aRunType) {
+  switch (aRunType) {
+    case TS_RT_PLAIN:
+      return "TS_RT_PLAIN";
+    case TS_RT_HIDDEN:
+      return "TS_RT_HIDDEN";
+    case TS_RT_OPAQUE:
+      return "TS_RT_OPAQUE";
+    default:
+      return "Unknown";
+  }
+}
+
+static nsCString GetColorName(const TF_DA_COLOR& aColor) {
+  switch (aColor.type) {
+    case TF_CT_NONE:
+      return "TF_CT_NONE"_ns;
+    case TF_CT_SYSCOLOR:
+      return nsPrintfCString("TF_CT_SYSCOLOR, nIndex:0x%08X",
+                             static_cast<int32_t>(aColor.nIndex));
+    case TF_CT_COLORREF:
+      return nsPrintfCString("TF_CT_COLORREF, cr:0x%08X",
+                             static_cast<int32_t>(aColor.cr));
+      break;
+    default:
+      return nsPrintfCString("Unknown(%08X)",
+                             static_cast<int32_t>(aColor.type));
+  }
+}
+
+static nsCString GetLineStyleName(TF_DA_LINESTYLE aLineStyle) {
+  switch (aLineStyle) {
+    case TF_LS_NONE:
+      return "TF_LS_NONE"_ns;
+    case TF_LS_SOLID:
+      return "TF_LS_SOLID"_ns;
+    case TF_LS_DOT:
+      return "TF_LS_DOT"_ns;
+    case TF_LS_DASH:
+      return "TF_LS_DASH"_ns;
+    case TF_LS_SQUIGGLE:
+      return "TF_LS_SQUIGGLE"_ns;
+    default: {
+      return nsPrintfCString("Unknown(%08X)", static_cast<int32_t>(aLineStyle));
+    }
+  }
+}
+
+static nsCString GetClauseAttrName(TF_DA_ATTR_INFO aAttr) {
+  switch (aAttr) {
+    case TF_ATTR_INPUT:
+      return "TF_ATTR_INPUT"_ns;
+    case TF_ATTR_TARGET_CONVERTED:
+      return "TF_ATTR_TARGET_CONVERTED"_ns;
+    case TF_ATTR_CONVERTED:
+      return "TF_ATTR_CONVERTED"_ns;
+    case TF_ATTR_TARGET_NOTCONVERTED:
+      return "TF_ATTR_TARGET_NOTCONVERTED"_ns;
+    case TF_ATTR_INPUT_ERROR:
+      return "TF_ATTR_INPUT_ERROR"_ns;
+    case TF_ATTR_FIXEDCONVERTED:
+      return "TF_ATTR_FIXEDCONVERTED"_ns;
+    case TF_ATTR_OTHER:
+      return "TF_ATTR_OTHER"_ns;
+    default: {
+      return nsPrintfCString("Unknown(%08X)", static_cast<int32_t>(aAttr));
+    }
+  }
+}
+
+static nsCString GetDisplayAttrStr(const TF_DISPLAYATTRIBUTE& aDispAttr) {
+  nsCString str;
+  str = "crText:{ ";
+  str += GetColorName(aDispAttr.crText);
+  str += " }, crBk:{ ";
+  str += GetColorName(aDispAttr.crBk);
+  str += " }, lsStyle: ";
+  str += GetLineStyleName(aDispAttr.lsStyle);
+  str += ", fBoldLine: ";
+  str += GetBoolName(aDispAttr.fBoldLine);
+  str += ", crLine:{ ";
+  str += GetColorName(aDispAttr.crLine);
+  str += " }, bAttr: ";
+  str += GetClauseAttrName(aDispAttr.bAttr);
+  return str;
+}
+
+static const char* GetMouseButtonName(int16_t aButton) {
+  switch (aButton) {
+    case MouseButton::ePrimary:
+      return "LeftButton";
+    case MouseButton::eMiddle:
+      return "MiddleButton";
+    case MouseButton::eSecondary:
+      return "RightButton";
+    default:
+      return "UnknownButton";
+  }
+}
+
+#define ADD_SEPARATOR_IF_NECESSARY(aStr) \
+  if (!aStr.IsEmpty()) {                 \
+    aStr.AppendLiteral(", ");            \
+  }
+
+static nsCString GetMouseButtonsName(int16_t aButtons) {
+  if (!aButtons) {
+    return "no buttons"_ns;
+  }
+  nsCString names;
+  if (aButtons & MouseButtonsFlag::ePrimaryFlag) {
+    names = "LeftButton";
+  }
+  if (aButtons & MouseButtonsFlag::eSecondaryFlag) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += "RightButton";
+  }
+  if (aButtons & MouseButtonsFlag::eMiddleFlag) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += "MiddleButton";
+  }
+  if (aButtons & MouseButtonsFlag::e4thFlag) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += "4thButton";
+  }
+  if (aButtons & MouseButtonsFlag::e5thFlag) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += "5thButton";
+  }
+  return names;
+}
+
+static nsCString GetModifiersName(Modifiers aModifiers) {
+  if (aModifiers == MODIFIER_NONE) {
+    return "no modifiers"_ns;
+  }
+  nsCString names;
+  if (aModifiers & MODIFIER_ALT) {
+    names = NS_DOM_KEYNAME_ALT;
+  }
+  if (aModifiers & MODIFIER_ALTGRAPH) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += NS_DOM_KEYNAME_ALTGRAPH;
+  }
+  if (aModifiers & MODIFIER_CAPSLOCK) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += NS_DOM_KEYNAME_CAPSLOCK;
+  }
+  if (aModifiers & MODIFIER_CONTROL) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += NS_DOM_KEYNAME_CONTROL;
+  }
+  if (aModifiers & MODIFIER_FN) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += NS_DOM_KEYNAME_FN;
+  }
+  if (aModifiers & MODIFIER_FNLOCK) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += NS_DOM_KEYNAME_FNLOCK;
+  }
+  if (aModifiers & MODIFIER_META) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += NS_DOM_KEYNAME_META;
+  }
+  if (aModifiers & MODIFIER_NUMLOCK) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += NS_DOM_KEYNAME_NUMLOCK;
+  }
+  if (aModifiers & MODIFIER_SCROLLLOCK) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += NS_DOM_KEYNAME_SCROLLLOCK;
+  }
+  if (aModifiers & MODIFIER_SHIFT) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += NS_DOM_KEYNAME_SHIFT;
+  }
+  if (aModifiers & MODIFIER_SYMBOL) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += NS_DOM_KEYNAME_SYMBOL;
+  }
+  if (aModifiers & MODIFIER_SYMBOLLOCK) {
+    ADD_SEPARATOR_IF_NECESSARY(names);
+    names += NS_DOM_KEYNAME_SYMBOLLOCK;
+  }
+  return names;
+}
+
+class GetWritingModeName : public nsAutoCString {
+ public:
+  explicit GetWritingModeName(const WritingMode& aWritingMode) {
+    if (!aWritingMode.IsVertical()) {
+      AssignLiteral("Horizontal");
+      return;
+    }
+    if (aWritingMode.IsVerticalLR()) {
+      AssignLiteral("Vertical (LR)");
+      return;
+    }
+    AssignLiteral("Vertical (RL)");
+  }
+  virtual ~GetWritingModeName() {}
+};
+
+class GetEscapedUTF8String final : public NS_ConvertUTF16toUTF8 {
+ public:
+  explicit GetEscapedUTF8String(const nsAString& aString)
+      : NS_ConvertUTF16toUTF8(aString) {
+    Escape();
+  }
+  explicit GetEscapedUTF8String(const char16ptr_t aString)
+      : NS_ConvertUTF16toUTF8(aString) {
+    Escape();
+  }
+  GetEscapedUTF8String(const char16ptr_t aString, uint32_t aLength)
+      : NS_ConvertUTF16toUTF8(aString, aLength) {
+    Escape();
+  }
+
+ private:
+  void Escape() {
+    ReplaceSubstring("\r", "\\r");
+    ReplaceSubstring("\n", "\\n");
+    ReplaceSubstring("\t", "\\t");
+  }
+};
+
+class GetInputScopeString : public nsAutoCString {
+ public:
+  explicit GetInputScopeString(const nsTArray<InputScope>& aList) {
+    for (InputScope inputScope : aList) {
+      if (!IsEmpty()) {
+        AppendLiteral(", ");
+      }
+      switch (inputScope) {
+        case IS_DEFAULT:
+          AppendLiteral("IS_DEFAULT");
+          break;
+        case IS_URL:
+          AppendLiteral("IS_URL");
+          break;
+        case IS_FILE_FULLFILEPATH:
+          AppendLiteral("IS_FILE_FULLFILEPATH");
+          break;
+        case IS_FILE_FILENAME:
+          AppendLiteral("IS_FILE_FILENAME");
+          break;
+        case IS_EMAIL_USERNAME:
+          AppendLiteral("IS_EMAIL_USERNAME");
+          break;
+        case IS_EMAIL_SMTPEMAILADDRESS:
+          AppendLiteral("IS_EMAIL_SMTPEMAILADDRESS");
+          break;
+        case IS_LOGINNAME:
+          AppendLiteral("IS_LOGINNAME");
+          break;
+        case IS_PERSONALNAME_FULLNAME:
+          AppendLiteral("IS_PERSONALNAME_FULLNAME");
+          break;
+        case IS_PERSONALNAME_PREFIX:
+          AppendLiteral("IS_PERSONALNAME_PREFIX");
+          break;
+        case IS_PERSONALNAME_GIVENNAME:
+          AppendLiteral("IS_PERSONALNAME_GIVENNAME");
+          break;
+        case IS_PERSONALNAME_MIDDLENAME:
+          AppendLiteral("IS_PERSONALNAME_MIDDLENAME");
+          break;
+        case IS_PERSONALNAME_SURNAME:
+          AppendLiteral("IS_PERSONALNAME_SURNAME");
+          break;
+        case IS_PERSONALNAME_SUFFIX:
+          AppendLiteral("IS_PERSONALNAME_SUFFIX");
+          break;
+        case IS_ADDRESS_FULLPOSTALADDRESS:
+          AppendLiteral("IS_ADDRESS_FULLPOSTALADDRESS");
+          break;
+        case IS_ADDRESS_POSTALCODE:
+          AppendLiteral("IS_ADDRESS_POSTALCODE");
+          break;
+        case IS_ADDRESS_STREET:
+          AppendLiteral("IS_ADDRESS_STREET");
+          break;
+        case IS_ADDRESS_STATEORPROVINCE:
+          AppendLiteral("IS_ADDRESS_STATEORPROVINCE");
+          break;
+        case IS_ADDRESS_CITY:
+          AppendLiteral("IS_ADDRESS_CITY");
+          break;
+        case IS_ADDRESS_COUNTRYNAME:
+          AppendLiteral("IS_ADDRESS_COUNTRYNAME");
+          break;
+        case IS_ADDRESS_COUNTRYSHORTNAME:
+          AppendLiteral("IS_ADDRESS_COUNTRYSHORTNAME");
+          break;
+        case IS_CURRENCY_AMOUNTANDSYMBOL:
+          AppendLiteral("IS_CURRENCY_AMOUNTANDSYMBOL");
+          break;
+        case IS_CURRENCY_AMOUNT:
+          AppendLiteral("IS_CURRENCY_AMOUNT");
+          break;
+        case IS_DATE_FULLDATE:
+          AppendLiteral("IS_DATE_FULLDATE");
+          break;
+        case IS_DATE_MONTH:
+          AppendLiteral("IS_DATE_MONTH");
+          break;
+        case IS_DATE_DAY:
+          AppendLiteral("IS_DATE_DAY");
+          break;
+        case IS_DATE_YEAR:
+          AppendLiteral("IS_DATE_YEAR");
+          break;
+        case IS_DATE_MONTHNAME:
+          AppendLiteral("IS_DATE_MONTHNAME");
+          break;
+        case IS_DATE_DAYNAME:
+          AppendLiteral("IS_DATE_DAYNAME");
+          break;
+        case IS_DIGITS:
+          AppendLiteral("IS_DIGITS");
+          break;
+        case IS_NUMBER:
+          AppendLiteral("IS_NUMBER");
+          break;
+        case IS_ONECHAR:
+          AppendLiteral("IS_ONECHAR");
+          break;
+        case IS_PASSWORD:
+          AppendLiteral("IS_PASSWORD");
+          break;
+        case IS_TELEPHONE_FULLTELEPHONENUMBER:
+          AppendLiteral("IS_TELEPHONE_FULLTELEPHONENUMBER");
+          break;
+        case IS_TELEPHONE_COUNTRYCODE:
+          AppendLiteral("IS_TELEPHONE_COUNTRYCODE");
+          break;
+        case IS_TELEPHONE_AREACODE:
+          AppendLiteral("IS_TELEPHONE_AREACODE");
+          break;
+        case IS_TELEPHONE_LOCALNUMBER:
+          AppendLiteral("IS_TELEPHONE_LOCALNUMBER");
+          break;
+        case IS_TIME_FULLTIME:
+          AppendLiteral("IS_TIME_FULLTIME");
+          break;
+        case IS_TIME_HOUR:
+          AppendLiteral("IS_TIME_HOUR");
+          break;
+        case IS_TIME_MINORSEC:
+          AppendLiteral("IS_TIME_MINORSEC");
+          break;
+        case IS_NUMBER_FULLWIDTH:
+          AppendLiteral("IS_NUMBER_FULLWIDTH");
+          break;
+        case IS_ALPHANUMERIC_HALFWIDTH:
+          AppendLiteral("IS_ALPHANUMERIC_HALFWIDTH");
+          break;
+        case IS_ALPHANUMERIC_FULLWIDTH:
+          AppendLiteral("IS_ALPHANUMERIC_FULLWIDTH");
+          break;
+        case IS_CURRENCY_CHINESE:
+          AppendLiteral("IS_CURRENCY_CHINESE");
+          break;
+        case IS_BOPOMOFO:
+          AppendLiteral("IS_BOPOMOFO");
+          break;
+        case IS_HIRAGANA:
+          AppendLiteral("IS_HIRAGANA");
+          break;
+        case IS_KATAKANA_HALFWIDTH:
+          AppendLiteral("IS_KATAKANA_HALFWIDTH");
+          break;
+        case IS_KATAKANA_FULLWIDTH:
+          AppendLiteral("IS_KATAKANA_FULLWIDTH");
+          break;
+        case IS_HANJA:
+          AppendLiteral("IS_HANJA");
+          break;
+        case IS_PHRASELIST:
+          AppendLiteral("IS_PHRASELIST");
+          break;
+        case IS_REGULAREXPRESSION:
+          AppendLiteral("IS_REGULAREXPRESSION");
+          break;
+        case IS_SRGS:
+          AppendLiteral("IS_SRGS");
+          break;
+        case IS_XML:
+          AppendLiteral("IS_XML");
+          break;
+        case IS_PRIVATE:
+          AppendLiteral("IS_PRIVATE");
+          break;
+        default:
+          AppendPrintf("Unknown Value(%d)", inputScope);
+          break;
+      }
+    }
+  }
+};
+
+/******************************************************************/
+/* InputScopeImpl                                                 */
+/******************************************************************/
+
+class InputScopeImpl final : public ITfInputScope {
+  ~InputScopeImpl() {}
+
+ public:
+  explicit InputScopeImpl(const nsTArray<InputScope>& aList)
+      : mInputScopes(aList.Clone()) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Info,
+        ("0x%p InputScopeImpl(%s)", this, GetInputScopeString(aList).get()));
+  }
+
+  NS_INLINE_DECL_IUNKNOWN_REFCOUNTING(InputScopeImpl)
+
+  STDMETHODIMP QueryInterface(REFIID riid, void** ppv) {
+    *ppv = nullptr;
+    if ((IID_IUnknown == riid) || (IID_ITfInputScope == riid)) {
+      *ppv = static_cast<ITfInputScope*>(this);
+    }
+    if (*ppv) {
+      AddRef();
+      return S_OK;
+    }
+    return E_NOINTERFACE;
+  }
+
+  STDMETHODIMP GetInputScopes(InputScope** pprgInputScopes, UINT* pcCount) {
+    uint32_t count = (mInputScopes.IsEmpty() ? 1 : mInputScopes.Length());
+
+    InputScope* pScope =
+        (InputScope*)CoTaskMemAlloc(sizeof(InputScope) * count);
+    NS_ENSURE_TRUE(pScope, E_OUTOFMEMORY);
+
+    if (mInputScopes.IsEmpty()) {
+      *pScope = IS_DEFAULT;
+      *pcCount = 1;
+      *pprgInputScopes = pScope;
+      return S_OK;
+    }
+
+    *pcCount = 0;
+
+    for (uint32_t idx = 0; idx < count; idx++) {
+      *(pScope + idx) = mInputScopes[idx];
+      (*pcCount)++;
+    }
+
+    *pprgInputScopes = pScope;
+    return S_OK;
+  }
+
+  STDMETHODIMP GetPhrase(BSTR** ppbstrPhrases, UINT* pcCount) {
+    return E_NOTIMPL;
+  }
+  STDMETHODIMP GetRegularExpression(BSTR* pbstrRegExp) { return E_NOTIMPL; }
+  STDMETHODIMP GetSRGS(BSTR* pbstrSRGS) { return E_NOTIMPL; }
+  STDMETHODIMP GetXML(BSTR* pbstrXML) { return E_NOTIMPL; }
+
+ private:
+  nsTArray<InputScope> mInputScopes;
+};
+
+/******************************************************************/
+/* TSFStaticSink                                                  */
+/******************************************************************/
+
+class TSFStaticSink final : public ITfInputProcessorProfileActivationSink {
+ public:
+  static TSFStaticSink* GetInstance() {
+    if (!sInstance) {
+      RefPtr<ITfThreadMgr> threadMgr = TSFTextStore::GetThreadMgr();
+      if (NS_WARN_IF(!threadMgr)) {
+        MOZ_LOG(
+            gIMELog, LogLevel::Error,
+            ("TSFStaticSink::GetInstance() FAILED to initialize TSFStaticSink "
+             "instance due to no ThreadMgr instance"));
+        return nullptr;
+      }
+      RefPtr<ITfInputProcessorProfiles> inputProcessorProfiles =
+          TSFTextStore::GetInputProcessorProfiles();
+      if (NS_WARN_IF(!inputProcessorProfiles)) {
+        MOZ_LOG(
+            gIMELog, LogLevel::Error,
+            ("TSFStaticSink::GetInstance() FAILED to initialize TSFStaticSink "
+             "instance due to no InputProcessorProfiles instance"));
+        return nullptr;
+      }
+      RefPtr<TSFStaticSink> staticSink = new TSFStaticSink();
+      if (NS_WARN_IF(!staticSink->Init(threadMgr, inputProcessorProfiles))) {
+        staticSink->Destroy();
+        MOZ_LOG(
+            gIMELog, LogLevel::Error,
+            ("TSFStaticSink::GetInstance() FAILED to initialize TSFStaticSink "
+             "instance"));
+        return nullptr;
+      }
+      sInstance = staticSink.forget();
+    }
+    return sInstance;
+  }
+
+  static void Shutdown() {
+    if (sInstance) {
+      sInstance->Destroy();
+      sInstance = nullptr;
+    }
+  }
+
+  bool Init(ITfThreadMgr* aThreadMgr,
+            ITfInputProcessorProfiles* aInputProcessorProfiles);
+  STDMETHODIMP QueryInterface(REFIID riid, void** ppv) {
+    *ppv = nullptr;
+    if (IID_IUnknown == riid ||
+        IID_ITfInputProcessorProfileActivationSink == riid) {
+      *ppv = static_cast<ITfInputProcessorProfileActivationSink*>(this);
+    }
+    if (*ppv) {
+      AddRef();
+      return S_OK;
+    }
+    return E_NOINTERFACE;
+  }
+
+  NS_INLINE_DECL_IUNKNOWN_REFCOUNTING(TSFStaticSink)
+
+  const nsString& GetActiveTIPKeyboardDescription() const {
+    return mActiveTIPKeyboardDescription;
+  }
+
+  static bool IsIMM_IMEActive() {
+    // Use IMM API until TSFStaticSink starts to work.
+    if (!sInstance || !sInstance->EnsureInitActiveTIPKeyboard()) {
+      return IsIMM_IME(::GetKeyboardLayout(0));
+    }
+    return sInstance->mIsIMM_IME;
+  }
+
+  static bool IsIMM_IME(HKL aHKL) {
+    return (::ImmGetIMEFileNameW(aHKL, nullptr, 0) > 0);
+  }
+
+  static bool IsTraditionalChinese() {
+    EnsureInstance();
+    return sInstance && sInstance->IsTraditionalChineseInternal();
+  }
+  static bool IsSimplifiedChinese() {
+    EnsureInstance();
+    return sInstance && sInstance->IsSimplifiedChineseInternal();
+  }
+  static bool IsJapanese() {
+    EnsureInstance();
+    return sInstance && sInstance->IsJapaneseInternal();
+  }
+  static bool IsKorean() {
+    EnsureInstance();
+    return sInstance && sInstance->IsKoreanInternal();
+  }
+
+  /**
+   * ActiveTIP() returns an ID for currently active TIP.
+   * Please note that this method is expensive due to needs a lot of GUID
+   * comparations if active language ID is one of CJKT.  If you need to
+   * check TIPs for a specific language, you should check current language
+   * first.
+   */
+  static TextInputProcessorID ActiveTIP() {
+    EnsureInstance();
+    if (!sInstance || !sInstance->EnsureInitActiveTIPKeyboard()) {
+      return TextInputProcessorID::eUnknown;
+    }
+    sInstance->ComputeActiveTextInputProcessor();
+    if (NS_WARN_IF(sInstance->mActiveTIP ==
+                   TextInputProcessorID::eNotComputed)) {
+      return TextInputProcessorID::eUnknown;
+    }
+    return sInstance->mActiveTIP;
+  }
+
+  static bool GetActiveTIPNameForTelemetry(nsAString& aName) {
+    if (!sInstance || !sInstance->EnsureInitActiveTIPKeyboard()) {
+      return false;
+    }
+    if (sInstance->mActiveTIPGUID == GUID_NULL) {
+      aName.Truncate();
+      aName.AppendPrintf("0x%04X", sInstance->mLangID);
+      return true;
+    }
+    // key should be "LocaleID|Description".  Although GUID of the
+    // profile is unique key since description may be localized for system
+    // language, unfortunately, it's too long to record as key with its
+    // description.  Therefore, we should record only the description with
+    // LocaleID because Microsoft IME may not include language information.
+    // 72 is kMaximumKeyStringLength in TelemetryScalar.cpp
+    aName.Truncate();
+    aName.AppendPrintf("0x%04X|", sInstance->mLangID);
+    nsAutoString description;
+    description.Assign(sInstance->mActiveTIPKeyboardDescription);
+    static const uint32_t kMaxDescriptionLength = 72 - aName.Length();
+    if (description.Length() > kMaxDescriptionLength) {
+      if (NS_IS_LOW_SURROGATE(description[kMaxDescriptionLength - 1]) &&
+          NS_IS_HIGH_SURROGATE(description[kMaxDescriptionLength - 2])) {
+        description.Truncate(kMaxDescriptionLength - 2);
+      } else {
+        description.Truncate(kMaxDescriptionLength - 1);
+      }
+      // U+2026 is "..."
+      description.Append(char16_t(0x2026));
+    }
+    aName.Append(description);
+    return true;
+  }
+
+  static bool IsMSChangJieOrMSQuickActive() {
+    // ActiveTIP() is expensive if it hasn't computed active TIP yet.
+    // For avoiding unnecessary computation, we should check if the language
+    // for current TIP is Traditional Chinese.
+    if (!IsTraditionalChinese()) {
+      return false;
+    }
+    switch (ActiveTIP()) {
+      case TextInputProcessorID::eMicrosoftChangJie:
+      case TextInputProcessorID::eMicrosoftQuick:
+        return true;
+      default:
+        return false;
+    }
+  }
+
+  static bool IsMSPinyinOrMSWubiActive() {
+    // ActiveTIP() is expensive if it hasn't computed active TIP yet.
+    // For avoiding unnecessary computation, we should check if the language
+    // for current TIP is Simplified Chinese.
+    if (!IsSimplifiedChinese()) {
+      return false;
+    }
+    switch (ActiveTIP()) {
+      case TextInputProcessorID::eMicrosoftPinyin:
+      case TextInputProcessorID::eMicrosoftWubi:
+        return true;
+      default:
+        return false;
+    }
+  }
+
+  static bool IsMSJapaneseIMEActive() {
+    // ActiveTIP() is expensive if it hasn't computed active TIP yet.
+    // For avoiding unnecessary computation, we should check if the language
+    // for current TIP is Japanese.
+    if (!IsJapanese()) {
+      return false;
+    }
+    return ActiveTIP() == TextInputProcessorID::eMicrosoftIMEForJapanese;
+  }
+
+  static bool IsGoogleJapaneseInputActive() {
+    // ActiveTIP() is expensive if it hasn't computed active TIP yet.
+    // For avoiding unnecessary computation, we should check if the language
+    // for current TIP is Japanese.
+    if (!IsJapanese()) {
+      return false;
+    }
+    return ActiveTIP() == TextInputProcessorID::eGoogleJapaneseInput;
+  }
+
+  static bool IsATOKActive() {
+    // ActiveTIP() is expensive if it hasn't computed active TIP yet.
+    // For avoiding unnecessary computation, we should check if active TIP is
+    // ATOK first since it's cheaper.
+    return IsJapanese() && sInstance->IsATOKActiveInternal();
+  }
+
+  // Note that ATOK 2011 - 2016 refers native caret position for deciding its
+  // popup window position.
+  static bool IsATOKReferringNativeCaretActive() {
+    // ActiveTIP() is expensive if it hasn't computed active TIP yet.
+    // For avoiding unnecessary computation, we should check if active TIP is
+    // ATOK first since it's cheaper.
+    if (!IsJapanese() || !sInstance->IsATOKActiveInternal()) {
+      return false;
+    }
+    switch (ActiveTIP()) {
+      case TextInputProcessorID::eATOK2011:
+      case TextInputProcessorID::eATOK2012:
+      case TextInputProcessorID::eATOK2013:
+      case TextInputProcessorID::eATOK2014:
+      case TextInputProcessorID::eATOK2015:
+        return true;
+      default:
+        return false;
+    }
+  }
+
+ private:
+  static void EnsureInstance() {
+    if (!sInstance) {
+      RefPtr<TSFStaticSink> staticSink = GetInstance();
+      Unused << staticSink;
+    }
+  }
+
+  bool IsTraditionalChineseInternal() const { return mLangID == 0x0404; }
+  bool IsSimplifiedChineseInternal() const { return mLangID == 0x0804; }
+  bool IsJapaneseInternal() const { return mLangID == 0x0411; }
+  bool IsKoreanInternal() const { return mLangID == 0x0412; }
+
+  bool IsATOKActiveInternal() {
+    EnsureInitActiveTIPKeyboard();
+    // FYI: Name of packaged ATOK includes the release year like "ATOK 2015".
+    //      Name of ATOK Passport (subscription) equals "ATOK".
+    return StringBeginsWith(mActiveTIPKeyboardDescription, u"ATOK "_ns) ||
+           mActiveTIPKeyboardDescription.EqualsLiteral("ATOK");
+  }
+
+  void ComputeActiveTextInputProcessor() {
+    if (mActiveTIP != TextInputProcessorID::eNotComputed) {
+      return;
+    }
+
+    if (mActiveTIPGUID == GUID_NULL) {
+      mActiveTIP = TextInputProcessorID::eNone;
+      return;
+    }
+
+    // Comparing GUID is slow. So, we should use language information to
+    // reduce the comparing cost for TIP which is not we do not support
+    // specifically since they are always compared with all supported TIPs.
+    switch (mLangID) {
+      case 0x0404:
+        mActiveTIP = ComputeActiveTIPAsTraditionalChinese();
+        break;
+      case 0x0411:
+        mActiveTIP = ComputeActiveTIPAsJapanese();
+        break;
+      case 0x0412:
+        mActiveTIP = ComputeActiveTIPAsKorean();
+        break;
+      case 0x0804:
+        mActiveTIP = ComputeActiveTIPAsSimplifiedChinese();
+        break;
+      default:
+        mActiveTIP = TextInputProcessorID::eUnknown;
+        break;
+    }
+    // Special case for Keyman Desktop, it is available for any languages.
+    // Therefore, we need to check it only if we don't know the active TIP.
+    if (mActiveTIP != TextInputProcessorID::eUnknown) {
+      return;
+    }
+
+    // Note that keyboard layouts for Keyman assign its GUID on install
+    // randomly, but CLSID is constant in any environments.
+    // https://bugzilla.mozilla.org/show_bug.cgi?id=1670834#c7
+    // https://github.com/keymanapp/keyman/blob/318c73a9e1d571d942837ff9964590626e5bd5aa/windows/src/engine/kmtip/globals.cpp#L37
+    // {FE0420F1-38D1-4B4C-96BF-E7E20A74CFB7}
+    static constexpr CLSID kKeymanDesktop_CLSID = {
+        0xFE0420F1,
+        0x38D1,
+        0x4B4C,
+        {0x96, 0xBF, 0xE7, 0xE2, 0x0A, 0x74, 0xCF, 0xB7}};
+    if (mActiveTIPCLSID == kKeymanDesktop_CLSID) {
+      mActiveTIP = TextInputProcessorID::eKeymanDesktop;
+    }
+  }
+
+  TextInputProcessorID ComputeActiveTIPAsJapanese() {
+    // {A76C93D9-5523-4E90-AAFA-4DB112F9AC76} (Win7, Win8.1, Win10)
+    static constexpr GUID kMicrosoftIMEForJapaneseGUID = {
+        0xA76C93D9,
+        0x5523,
+        0x4E90,
+        {0xAA, 0xFA, 0x4D, 0xB1, 0x12, 0xF9, 0xAC, 0x76}};
+    if (mActiveTIPGUID == kMicrosoftIMEForJapaneseGUID) {
+      return TextInputProcessorID::eMicrosoftIMEForJapanese;
+    }
+    // {54EDCC94-1524-4BB1-9FB7-7BABE4F4CA64}
+    static constexpr GUID kMicrosoftOfficeIME2010ForJapaneseGUID = {
+        0x54EDCC94,
+        0x1524,
+        0x4BB1,
+        {0x9F, 0xB7, 0x7B, 0xAB, 0xE4, 0xF4, 0xCA, 0x64}};
+    if (mActiveTIPGUID == kMicrosoftOfficeIME2010ForJapaneseGUID) {
+      return TextInputProcessorID::eMicrosoftOfficeIME2010ForJapanese;
+    }
+    // {773EB24E-CA1D-4B1B-B420-FA985BB0B80D}
+    static constexpr GUID kGoogleJapaneseInputGUID = {
+        0x773EB24E,
+        0xCA1D,
+        0x4B1B,
+        {0xB4, 0x20, 0xFA, 0x98, 0x5B, 0xB0, 0xB8, 0x0D}};
+    if (mActiveTIPGUID == kGoogleJapaneseInputGUID) {
+      return TextInputProcessorID::eGoogleJapaneseInput;
+    }
+    // {F9C24A5C-8A53-499D-9572-93B2FF582115}
+    static const GUID kATOK2011GUID = {
+        0xF9C24A5C,
+        0x8A53,
+        0x499D,
+        {0x95, 0x72, 0x93, 0xB2, 0xFF, 0x58, 0x21, 0x15}};
+    if (mActiveTIPGUID == kATOK2011GUID) {
+      return TextInputProcessorID::eATOK2011;
+    }
+    // {1DE01562-F445-401B-B6C3-E5B18DB79461}
+    static constexpr GUID kATOK2012GUID = {
+        0x1DE01562,
+        0xF445,
+        0x401B,
+        {0xB6, 0xC3, 0xE5, 0xB1, 0x8D, 0xB7, 0x94, 0x61}};
+    if (mActiveTIPGUID == kATOK2012GUID) {
+      return TextInputProcessorID::eATOK2012;
+    }
+    // {3C4DB511-189A-4168-B6EA-BFD0B4C85615}
+    static constexpr GUID kATOK2013GUID = {
+        0x3C4DB511,
+        0x189A,
+        0x4168,
+        {0xB6, 0xEA, 0xBF, 0xD0, 0xB4, 0xC8, 0x56, 0x15}};
+    if (mActiveTIPGUID == kATOK2013GUID) {
+      return TextInputProcessorID::eATOK2013;
+    }
+    // {4EF33B79-6AA9-4271-B4BF-9321C279381B}
+    static constexpr GUID kATOK2014GUID = {
+        0x4EF33B79,
+        0x6AA9,
+        0x4271,
+        {0xB4, 0xBF, 0x93, 0x21, 0xC2, 0x79, 0x38, 0x1B}};
+    if (mActiveTIPGUID == kATOK2014GUID) {
+      return TextInputProcessorID::eATOK2014;
+    }
+    // {EAB4DC00-CE2E-483D-A86A-E6B99DA9599A}
+    static constexpr GUID kATOK2015GUID = {
+        0xEAB4DC00,
+        0xCE2E,
+        0x483D,
+        {0xA8, 0x6A, 0xE6, 0xB9, 0x9D, 0xA9, 0x59, 0x9A}};
+    if (mActiveTIPGUID == kATOK2015GUID) {
+      return TextInputProcessorID::eATOK2015;
+    }
+    // {0B557B4C-5740-4110-A60A-1493FA10BF2B}
+    static constexpr GUID kATOK2016GUID = {
+        0x0B557B4C,
+        0x5740,
+        0x4110,
+        {0xA6, 0x0A, 0x14, 0x93, 0xFA, 0x10, 0xBF, 0x2B}};
+    if (mActiveTIPGUID == kATOK2016GUID) {
+      return TextInputProcessorID::eATOK2016;
+    }
+
+    // * ATOK 2017
+    //   - {6DBFD8F5-701D-11E6-920F-782BCBA6348F}
+    // * ATOK Passport (confirmed with version 31.1.2)
+    //   - {A38F2FD9-7199-45E1-841C-BE0313D8052F}
+
+    if (IsATOKActiveInternal()) {
+      return TextInputProcessorID::eATOKUnknown;
+    }
+
+    // {E6D66705-1EDA-4373-8D01-1D0CB2D054C7}
+    static constexpr GUID kJapanist10GUID = {
+        0xE6D66705,
+        0x1EDA,
+        0x4373,
+        {0x8D, 0x01, 0x1D, 0x0C, 0xB2, 0xD0, 0x54, 0xC7}};
+    if (mActiveTIPGUID == kJapanist10GUID) {
+      return TextInputProcessorID::eJapanist10;
+    }
+
+    return TextInputProcessorID::eUnknown;
+  }
+
+  TextInputProcessorID ComputeActiveTIPAsTraditionalChinese() {
+    // {B2F9C502-1742-11D4-9790-0080C882687E} (Win8.1, Win10)
+    static constexpr GUID kMicrosoftBopomofoGUID = {
+        0xB2F9C502,
+        0x1742,
+        0x11D4,
+        {0x97, 0x90, 0x00, 0x80, 0xC8, 0x82, 0x68, 0x7E}};
+    if (mActiveTIPGUID == kMicrosoftBopomofoGUID) {
+      return TextInputProcessorID::eMicrosoftBopomofo;
+    }
+    // {4BDF9F03-C7D3-11D4-B2AB-0080C882687E} (Win7, Win8.1, Win10)
+    static const GUID kMicrosoftChangJieGUID = {
+        0x4BDF9F03,
+        0xC7D3,
+        0x11D4,
+        {0xB2, 0xAB, 0x00, 0x80, 0xC8, 0x82, 0x68, 0x7E}};
+    if (mActiveTIPGUID == kMicrosoftChangJieGUID) {
+      return TextInputProcessorID::eMicrosoftChangJie;
+    }
+    // {761309DE-317A-11D4-9B5D-0080C882687E} (Win7)
+    static constexpr GUID kMicrosoftPhoneticGUID = {
+        0x761309DE,
+        0x317A,
+        0x11D4,
+        {0x9B, 0x5D, 0x00, 0x80, 0xC8, 0x82, 0x68, 0x7E}};
+    if (mActiveTIPGUID == kMicrosoftPhoneticGUID) {
+      return TextInputProcessorID::eMicrosoftPhonetic;
+    }
+    // {6024B45F-5C54-11D4-B921-0080C882687E} (Win7, Win8.1, Win10)
+    static constexpr GUID kMicrosoftQuickGUID = {
+        0x6024B45F,
+        0x5C54,
+        0x11D4,
+        {0xB9, 0x21, 0x00, 0x80, 0xC8, 0x82, 0x68, 0x7E}};
+    if (mActiveTIPGUID == kMicrosoftQuickGUID) {
+      return TextInputProcessorID::eMicrosoftQuick;
+    }
+    // {F3BA907A-6C7E-11D4-97FA-0080C882687E} (Win7)
+    static constexpr GUID kMicrosoftNewChangJieGUID = {
+        0xF3BA907A,
+        0x6C7E,
+        0x11D4,
+        {0x97, 0xFA, 0x00, 0x80, 0xC8, 0x82, 0x68, 0x7E}};
+    if (mActiveTIPGUID == kMicrosoftNewChangJieGUID) {
+      return TextInputProcessorID::eMicrosoftNewChangJie;
+    }
+    // {B2F9C502-1742-11D4-9790-0080C882687E} (Win7)
+    static constexpr GUID kMicrosoftNewPhoneticGUID = {
+        0xB2F9C502,
+        0x1742,
+        0x11D4,
+        {0x97, 0x90, 0x00, 0x80, 0xC8, 0x82, 0x68, 0x7E}};
+    if (mActiveTIPGUID == kMicrosoftNewPhoneticGUID) {
+      return TextInputProcessorID::eMicrosoftNewPhonetic;
+    }
+    // {0B883BA0-C1C7-11D4-87F9-0080C882687E} (Win7)
+    static constexpr GUID kMicrosoftNewQuickGUID = {
+        0x0B883BA0,
+        0xC1C7,
+        0x11D4,
+        {0x87, 0xF9, 0x00, 0x80, 0xC8, 0x82, 0x68, 0x7E}};
+    if (mActiveTIPGUID == kMicrosoftNewQuickGUID) {
+      return TextInputProcessorID::eMicrosoftNewQuick;
+    }
+
+    // NOTE: There are some other Traditional Chinese TIPs installed in Windows:
+    // * Chinese Traditional Array (version 6.0)
+    //   - {D38EFF65-AA46-4FD5-91A7-67845FB02F5B} (Win7, Win8.1)
+    // * Chinese Traditional DaYi (version 6.0)
+    //   - {037B2C25-480C-4D7F-B027-D6CA6B69788A} (Win7, Win8.1)
+
+    // {B58630B5-0ED3-4335-BBC9-E77BBCB43CAD}
+    static const GUID kFreeChangJieGUID = {
+        0xB58630B5,
+        0x0ED3,
+        0x4335,
+        {0xBB, 0xC9, 0xE7, 0x7B, 0xBC, 0xB4, 0x3C, 0xAD}};
+    if (mActiveTIPGUID == kFreeChangJieGUID) {
+      return TextInputProcessorID::eFreeChangJie;
+    }
+
+    return TextInputProcessorID::eUnknown;
+  }
+
+  TextInputProcessorID ComputeActiveTIPAsSimplifiedChinese() {
+    // FYI: This matches with neither "Microsoft Pinyin ABC Input Style" nor
+    //      "Microsoft Pinyin New Experience Input Style" on Win7.
+    // {FA550B04-5AD7-411F-A5AC-CA038EC515D7} (Win8.1, Win10)
+    static constexpr GUID kMicrosoftPinyinGUID = {
+        0xFA550B04,
+        0x5AD7,
+        0x411F,
+        {0xA5, 0xAC, 0xCA, 0x03, 0x8E, 0xC5, 0x15, 0xD7}};
+    if (mActiveTIPGUID == kMicrosoftPinyinGUID) {
+      return TextInputProcessorID::eMicrosoftPinyin;
+    }
+
+    // {F3BA9077-6C7E-11D4-97FA-0080C882687E} (Win7)
+    static constexpr GUID kMicrosoftPinyinNewExperienceInputStyleGUID = {
+        0xF3BA9077,
+        0x6C7E,
+        0x11D4,
+        {0x97, 0xFA, 0x00, 0x80, 0xC8, 0x82, 0x68, 0x7E}};
+    if (mActiveTIPGUID == kMicrosoftPinyinNewExperienceInputStyleGUID) {
+      return TextInputProcessorID::eMicrosoftPinyinNewExperienceInputStyle;
+    }
+    // {82590C13-F4DD-44F4-BA1D-8667246FDF8E} (Win8.1, Win10)
+    static constexpr GUID kMicrosoftWubiGUID = {
+        0x82590C13,
+        0xF4DD,
+        0x44F4,
+        {0xBA, 0x1D, 0x86, 0x67, 0x24, 0x6F, 0xDF, 0x8E}};
+    if (mActiveTIPGUID == kMicrosoftWubiGUID) {
+      return TextInputProcessorID::eMicrosoftWubi;
+    }
+    // NOTE: There are some other Simplified Chinese TIPs installed in Windows:
+    // * Chinese Simplified QuanPin (version 6.0)
+    //   - {54FC610E-6ABD-4685-9DDD-A130BDF1B170} (Win8.1)
+    // * Chinese Simplified ZhengMa (version 6.0)
+    //   - {733B4D81-3BC3-4132-B91A-E9CDD5E2BFC9} (Win8.1)
+    // * Chinese Simplified ShuangPin (version 6.0)
+    //   - {EF63706D-31C4-490E-9DBB-BD150ADC454B} (Win8.1)
+    // * Microsoft Pinyin ABC Input Style
+    //   - {FCA121D2-8C6D-41FB-B2DE-A2AD110D4820} (Win7)
+    return TextInputProcessorID::eUnknown;
+  }
+
+  TextInputProcessorID ComputeActiveTIPAsKorean() {
+    // {B5FE1F02-D5F2-4445-9C03-C568F23C99A1} (Win7, Win8.1, Win10)
+    static constexpr GUID kMicrosoftIMEForKoreanGUID = {
+        0xB5FE1F02,
+        0xD5F2,
+        0x4445,
+        {0x9C, 0x03, 0xC5, 0x68, 0xF2, 0x3C, 0x99, 0xA1}};
+    if (mActiveTIPGUID == kMicrosoftIMEForKoreanGUID) {
+      return TextInputProcessorID::eMicrosoftIMEForKorean;
+    }
+    // {B60AF051-257A-46BC-B9D3-84DAD819BAFB} (Win8.1, Win10)
+    static constexpr GUID kMicrosoftOldHangulGUID = {
+        0xB60AF051,
+        0x257A,
+        0x46BC,
+        {0xB9, 0xD3, 0x84, 0xDA, 0xD8, 0x19, 0xBA, 0xFB}};
+    if (mActiveTIPGUID == kMicrosoftOldHangulGUID) {
+      return TextInputProcessorID::eMicrosoftOldHangul;
+    }
+
+    // NOTE: There is the other Korean TIP installed in Windows:
+    // * Microsoft IME 2010
+    //   - {48878C45-93F9-4aaf-A6A1-272CD863C4F5} (Win7)
+
+    return TextInputProcessorID::eUnknown;
+  }
+
+ public:  // ITfInputProcessorProfileActivationSink
+  STDMETHODIMP OnActivated(DWORD, LANGID, REFCLSID, REFGUID, REFGUID, HKL,
+                           DWORD);
+
+ private:
+  TSFStaticSink();
+  virtual ~TSFStaticSink() {}
+
+  bool EnsureInitActiveTIPKeyboard();
+
+  void Destroy();
+
+  void GetTIPDescription(REFCLSID aTextService, LANGID aLangID,
+                         REFGUID aProfile, nsAString& aDescription);
+  bool IsTIPCategoryKeyboard(REFCLSID aTextService, LANGID aLangID,
+                             REFGUID aProfile);
+
+  TextInputProcessorID mActiveTIP;
+
+  // Cookie of installing ITfInputProcessorProfileActivationSink
+  DWORD mIPProfileCookie;
+
+  LANGID mLangID;
+
+  // True if current IME is implemented with IMM.
+  bool mIsIMM_IME;
+  // True if OnActivated() is already called
+  bool mOnActivatedCalled;
+
+  RefPtr<ITfThreadMgr> mThreadMgr;
+  RefPtr<ITfInputProcessorProfiles> mInputProcessorProfiles;
+
+  // Active TIP keyboard's description.  If active language profile isn't TIP,
+  // i.e., IMM-IME or just a keyboard layout, this is empty.
+  nsString mActiveTIPKeyboardDescription;
+
+  // Active TIP's GUID and CLSID
+  GUID mActiveTIPGUID;
+  CLSID mActiveTIPCLSID;
+
+  static StaticRefPtr<TSFStaticSink> sInstance;
+};
+
+StaticRefPtr<TSFStaticSink> TSFStaticSink::sInstance;
+
+TSFStaticSink::TSFStaticSink()
+    : mActiveTIP(TextInputProcessorID::eNotComputed),
+      mIPProfileCookie(TF_INVALID_COOKIE),
+      mLangID(0),
+      mIsIMM_IME(false),
+      mOnActivatedCalled(false),
+      mActiveTIPGUID(GUID_NULL) {}
+
+bool TSFStaticSink::Init(ITfThreadMgr* aThreadMgr,
+                         ITfInputProcessorProfiles* aInputProcessorProfiles) {
+  MOZ_ASSERT(!mThreadMgr && !mInputProcessorProfiles,
+             "TSFStaticSink::Init() must be called only once");
+
+  mThreadMgr = aThreadMgr;
+  mInputProcessorProfiles = aInputProcessorProfiles;
+
+  RefPtr<ITfSource> source;
+  HRESULT hr =
+      mThreadMgr->QueryInterface(IID_ITfSource, getter_AddRefs(source));
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p TSFStaticSink::Init() FAILED to get ITfSource "
+             "instance (0x%08lX)",
+             this, hr));
+    return false;
+  }
+
+  // NOTE: On Vista or later, Windows let us know activate IME changed only
+  //       with ITfInputProcessorProfileActivationSink.
+  hr = source->AdviseSink(
+      IID_ITfInputProcessorProfileActivationSink,
+      static_cast<ITfInputProcessorProfileActivationSink*>(this),
+      &mIPProfileCookie);
+  if (FAILED(hr) || mIPProfileCookie == TF_INVALID_COOKIE) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p TSFStaticSink::Init() FAILED to install "
+             "ITfInputProcessorProfileActivationSink (0x%08lX)",
+             this, hr));
+    return false;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFStaticSink::Init(), "
+           "mIPProfileCookie=0x%08lX",
+           this, mIPProfileCookie));
+  return true;
+}
+
+void TSFStaticSink::Destroy() {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFStaticSink::Shutdown() "
+           "mIPProfileCookie=0x%08lX",
+           this, mIPProfileCookie));
+
+  if (mIPProfileCookie != TF_INVALID_COOKIE) {
+    RefPtr<ITfSource> source;
+    HRESULT hr =
+        mThreadMgr->QueryInterface(IID_ITfSource, getter_AddRefs(source));
+    if (FAILED(hr)) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFStaticSink::Shutdown() FAILED to get "
+               "ITfSource instance (0x%08lX)",
+               this, hr));
+    } else {
+      hr = source->UnadviseSink(mIPProfileCookie);
+      if (FAILED(hr)) {
+        MOZ_LOG(gIMELog, LogLevel::Error,
+                ("0x%p   TSFTextStore::Shutdown() FAILED to uninstall "
+                 "ITfInputProcessorProfileActivationSink (0x%08lX)",
+                 this, hr));
+      }
+    }
+  }
+
+  mThreadMgr = nullptr;
+  mInputProcessorProfiles = nullptr;
+}
+
+STDMETHODIMP
+TSFStaticSink::OnActivated(DWORD dwProfileType, LANGID langid, REFCLSID rclsid,
+                           REFGUID catid, REFGUID guidProfile, HKL hkl,
+                           DWORD dwFlags) {
+  if ((dwFlags & TF_IPSINK_FLAG_ACTIVE) &&
+      (dwProfileType == TF_PROFILETYPE_KEYBOARDLAYOUT ||
+       catid == GUID_TFCAT_TIP_KEYBOARD)) {
+    mOnActivatedCalled = true;
+    mActiveTIP = TextInputProcessorID::eNotComputed;
+    mActiveTIPGUID = guidProfile;
+    mActiveTIPCLSID = rclsid;
+    mLangID = langid & 0xFFFF;
+    mIsIMM_IME = IsIMM_IME(hkl);
+    GetTIPDescription(rclsid, langid, guidProfile,
+                      mActiveTIPKeyboardDescription);
+    if (mActiveTIPGUID != GUID_NULL) {
+      // key should be "LocaleID|Description".  Although GUID of the
+      // profile is unique key since description may be localized for system
+      // language, unfortunately, it's too long to record as key with its
+      // description.  Therefore, we should record only the description with
+      // LocaleID because Microsoft IME may not include language information.
+      // 72 is kMaximumKeyStringLength in TelemetryScalar.cpp
+      nsAutoString key;
+      TSFStaticSink::GetActiveTIPNameForTelemetry(key);
+      Telemetry::ScalarSet(Telemetry::ScalarID::WIDGET_IME_NAME_ON_WINDOWS, key,
+                           true);
+    }
+    // Notify IMEHandler of changing active keyboard layout.
+    IMEHandler::OnKeyboardLayoutChanged();
+  }
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFStaticSink::OnActivated(dwProfileType=%s (0x%08lX), "
+           "langid=0x%08X, rclsid=%s, catid=%s, guidProfile=%s, hkl=0x%p, "
+           "dwFlags=0x%08lX (TF_IPSINK_FLAG_ACTIVE: %s)), mIsIMM_IME=%s, "
+           "mActiveTIPDescription=\"%s\"",
+           this,
+           dwProfileType == TF_PROFILETYPE_INPUTPROCESSOR
+               ? "TF_PROFILETYPE_INPUTPROCESSOR"
+           : dwProfileType == TF_PROFILETYPE_KEYBOARDLAYOUT
+               ? "TF_PROFILETYPE_KEYBOARDLAYOUT"
+               : "Unknown",
+           dwProfileType, langid, GetCLSIDNameStr(rclsid).get(),
+           GetGUIDNameStr(catid).get(), GetGUIDNameStr(guidProfile).get(), hkl,
+           dwFlags, GetBoolName(dwFlags & TF_IPSINK_FLAG_ACTIVE),
+           GetBoolName(mIsIMM_IME),
+           NS_ConvertUTF16toUTF8(mActiveTIPKeyboardDescription).get()));
+  return S_OK;
+}
+
+bool TSFStaticSink::EnsureInitActiveTIPKeyboard() {
+  if (mOnActivatedCalled) {
+    return true;
+  }
+
+  RefPtr<ITfInputProcessorProfileMgr> profileMgr;
+  HRESULT hr = mInputProcessorProfiles->QueryInterface(
+      IID_ITfInputProcessorProfileMgr, getter_AddRefs(profileMgr));
+  if (FAILED(hr) || !profileMgr) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFStaticSink::EnsureInitActiveLanguageProfile(), FAILED "
+             "to get input processor profile manager, hr=0x%08lX",
+             this, hr));
+    return false;
+  }
+
+  TF_INPUTPROCESSORPROFILE profile;
+  hr = profileMgr->GetActiveProfile(GUID_TFCAT_TIP_KEYBOARD, &profile);
+  if (hr == S_FALSE) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFStaticSink::EnsureInitActiveLanguageProfile(), FAILED "
+             "to get active keyboard layout profile due to no active profile, "
+             "hr=0x%08lX",
+             this, hr));
+    // XXX Should we call OnActivated() with arguments like non-TIP in this
+    //     case?
+    return false;
+  }
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFStaticSink::EnsureInitActiveLanguageProfile(), FAILED "
+             "to get active TIP keyboard, hr=0x%08lX",
+             this, hr));
+    return false;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFStaticSink::EnsureInitActiveLanguageProfile(), "
+           "calling OnActivated() manually...",
+           this));
+  OnActivated(profile.dwProfileType, profile.langid, profile.clsid,
+              profile.catid, profile.guidProfile, ::GetKeyboardLayout(0),
+              TF_IPSINK_FLAG_ACTIVE);
+  return true;
+}
+
+void TSFStaticSink::GetTIPDescription(REFCLSID aTextService, LANGID aLangID,
+                                      REFGUID aProfile,
+                                      nsAString& aDescription) {
+  aDescription.Truncate();
+
+  if (aTextService == CLSID_NULL || aProfile == GUID_NULL) {
+    return;
+  }
+
+  BSTR description = nullptr;
+  HRESULT hr = mInputProcessorProfiles->GetLanguageProfileDescription(
+      aTextService, aLangID, aProfile, &description);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFStaticSink::InitActiveTIPDescription() FAILED "
+             "due to GetLanguageProfileDescription() failure, hr=0x%08lX",
+             this, hr));
+    return;
+  }
+
+  if (description && description[0]) {
+    aDescription.Assign(description);
+  }
+  ::SysFreeString(description);
+}
+
+bool TSFStaticSink::IsTIPCategoryKeyboard(REFCLSID aTextService, LANGID aLangID,
+                                          REFGUID aProfile) {
+  if (aTextService == CLSID_NULL || aProfile == GUID_NULL) {
+    return false;
+  }
+
+  RefPtr<IEnumTfLanguageProfiles> enumLangProfiles;
+  HRESULT hr = mInputProcessorProfiles->EnumLanguageProfiles(
+      aLangID, getter_AddRefs(enumLangProfiles));
+  if (FAILED(hr) || !enumLangProfiles) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFStaticSink::IsTIPCategoryKeyboard(), FAILED "
+             "to get language profiles enumerator, hr=0x%08lX",
+             this, hr));
+    return false;
+  }
+
+  TF_LANGUAGEPROFILE profile;
+  ULONG fetch = 0;
+  while (SUCCEEDED(enumLangProfiles->Next(1, &profile, &fetch)) && fetch) {
+    // XXX We're not sure a profile is registered with two or more categories.
+    if (profile.clsid == aTextService && profile.guidProfile == aProfile &&
+        profile.catid == GUID_TFCAT_TIP_KEYBOARD) {
+      return true;
+    }
+  }
+  return false;
+}
+
+/******************************************************************/
+/* TSFTextStore                                                   */
+/******************************************************************/
+
+StaticRefPtr<ITfThreadMgr> TSFTextStore::sThreadMgr;
+StaticRefPtr<ITfMessagePump> TSFTextStore::sMessagePump;
+StaticRefPtr<ITfKeystrokeMgr> TSFTextStore::sKeystrokeMgr;
+StaticRefPtr<ITfDisplayAttributeMgr> TSFTextStore::sDisplayAttrMgr;
+StaticRefPtr<ITfCategoryMgr> TSFTextStore::sCategoryMgr;
+StaticRefPtr<ITfCompartment> TSFTextStore::sCompartmentForOpenClose;
+StaticRefPtr<ITfDocumentMgr> TSFTextStore::sDisabledDocumentMgr;
+StaticRefPtr<ITfContext> TSFTextStore::sDisabledContext;
+StaticRefPtr<ITfInputProcessorProfiles> TSFTextStore::sInputProcessorProfiles;
+StaticRefPtr<TSFTextStore> TSFTextStore::sEnabledTextStore;
+const MSG* TSFTextStore::sHandlingKeyMsg = nullptr;
+DWORD TSFTextStore::sClientId = 0;
+bool TSFTextStore::sIsKeyboardEventDispatched = false;
+
+#define TEXTSTORE_DEFAULT_VIEW (1)
+
+TSFTextStore::TSFTextStore()
+    : mEditCookie(0),
+      mSinkMask(0),
+      mLock(0),
+      mLockQueued(0),
+      mHandlingKeyMessage(0) {
+  // We hope that 5 or more actions don't occur at once.
+  mPendingActions.SetCapacity(5);
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::TSFTextStore() SUCCEEDED", this));
+}
+
+TSFTextStore::~TSFTextStore() {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore instance is destroyed", this));
+}
+
+bool TSFTextStore::Init(nsWindow* aWidget, const InputContext& aContext) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::Init(aWidget=0x%p)", this, aWidget));
+
+  if (NS_WARN_IF(!aWidget) || NS_WARN_IF(aWidget->Destroyed())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::Init() FAILED due to being initialized with "
+             "destroyed widget",
+             this));
+    return false;
+  }
+
+  if (mDocumentMgr) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::Init() FAILED due to already initialized",
+             this));
+    return false;
+  }
+
+  mWidget = aWidget;
+  if (NS_WARN_IF(!mWidget)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::Init() FAILED "
+             "due to aWidget is nullptr ",
+             this));
+    return false;
+  }
+  mDispatcher = mWidget->GetTextEventDispatcher();
+  if (NS_WARN_IF(!mDispatcher)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::Init() FAILED "
+             "due to aWidget->GetTextEventDispatcher() failure",
+             this));
+    return false;
+  }
+
+  mInPrivateBrowsing = aContext.mInPrivateBrowsing;
+  SetInputScope(aContext.mHTMLInputType, aContext.mHTMLInputMode);
+
+  if (aContext.mURI) {
+    // We don't need the document URL if it fails, let's ignore the error.
+    nsAutoCString spec;
+    if (NS_SUCCEEDED(aContext.mURI->GetSpec(spec))) {
+      CopyUTF8toUTF16(spec, mDocumentURL);
+    }
+  }
+
+  // Create document manager
+  RefPtr<ITfThreadMgr> threadMgr = sThreadMgr;
+  RefPtr<ITfDocumentMgr> documentMgr;
+  HRESULT hr = threadMgr->CreateDocumentMgr(getter_AddRefs(documentMgr));
+  if (NS_WARN_IF(FAILED(hr))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::Init() FAILED to create ITfDocumentMgr "
+             "(0x%08lX)",
+             this, hr));
+    return false;
+  }
+  if (NS_WARN_IF(mDestroyed)) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Error,
+        ("0x%p   TSFTextStore::Init() FAILED to create ITfDocumentMgr due to "
+         "TextStore being destroyed during calling "
+         "ITfThreadMgr::CreateDocumentMgr()",
+         this));
+    return false;
+  }
+  // Create context and add it to document manager
+  RefPtr<ITfContext> context;
+  hr = documentMgr->CreateContext(sClientId, 0,
+                                  static_cast<ITextStoreACP*>(this),
+                                  getter_AddRefs(context), &mEditCookie);
+  if (NS_WARN_IF(FAILED(hr))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::Init() FAILED to create the context "
+             "(0x%08lX)",
+             this, hr));
+    return false;
+  }
+  if (NS_WARN_IF(mDestroyed)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::Init() FAILED to create ITfContext due to "
+             "TextStore being destroyed during calling "
+             "ITfDocumentMgr::CreateContext()",
+             this));
+    return false;
+  }
+
+  hr = documentMgr->Push(context);
+  if (NS_WARN_IF(FAILED(hr))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::Init() FAILED to push the context (0x%08lX)",
+             this, hr));
+    return false;
+  }
+  if (NS_WARN_IF(mDestroyed)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::Init() FAILED to create ITfContext due to "
+             "TextStore being destroyed during calling ITfDocumentMgr::Push()",
+             this));
+    documentMgr->Pop(TF_POPF_ALL);
+    return false;
+  }
+
+  mDocumentMgr = documentMgr;
+  mContext = context;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::Init() succeeded: "
+           "mDocumentMgr=0x%p, mContext=0x%p, mEditCookie=0x%08lX",
+           this, mDocumentMgr.get(), mContext.get(), mEditCookie));
+
+  return true;
+}
+
+void TSFTextStore::Destroy() {
+  if (mBeingDestroyed) {
+    return;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::Destroy(), mLock=%s, "
+           "mComposition=%s, mHandlingKeyMessage=%u",
+           this, GetLockFlagNameStr(mLock).get(),
+           ToString(mComposition).c_str(), mHandlingKeyMessage));
+
+  mDestroyed = true;
+
+  // Destroy native caret first because it's not directly related to TSF and
+  // there may be another textstore which gets focus.  So, we should avoid
+  // to destroy caret after the new one recreates caret.
+  IMEHandler::MaybeDestroyNativeCaret();
+
+  if (mLock) {
+    mPendingDestroy = true;
+    return;
+  }
+
+  AutoRestore<bool> savedBeingDestroyed(mBeingDestroyed);
+  mBeingDestroyed = true;
+
+  // If there is composition, TSF keeps the composition even after the text
+  // store destroyed.  So, we should clear the composition here.
+  if (mComposition.isSome()) {
+    CommitCompositionInternal(false);
+  }
+
+  if (mSink) {
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::Destroy(), calling "
+             "ITextStoreACPSink::OnLayoutChange(TS_LC_DESTROY)...",
+             this));
+    RefPtr<ITextStoreACPSink> sink = mSink;
+    sink->OnLayoutChange(TS_LC_DESTROY, TEXTSTORE_DEFAULT_VIEW);
+  }
+
+  // If this is called during handling a keydown or keyup message, we should
+  // put off to release TSF objects until it completely finishes since
+  // MS-IME for Japanese refers some objects without grabbing them.
+  if (!mHandlingKeyMessage) {
+    ReleaseTSFObjects();
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::Destroy() succeeded", this));
+}
+
+void TSFTextStore::ReleaseTSFObjects() {
+  MOZ_ASSERT(!mHandlingKeyMessage);
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::ReleaseTSFObjects()", this));
+
+  mDocumentURL.Truncate();
+  mContext = nullptr;
+  if (mDocumentMgr) {
+    RefPtr<ITfDocumentMgr> documentMgr = mDocumentMgr.forget();
+    documentMgr->Pop(TF_POPF_ALL);
+  }
+  mSink = nullptr;
+  mWidget = nullptr;
+  mDispatcher = nullptr;
+
+  if (!mMouseTrackers.IsEmpty()) {
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::ReleaseTSFObjects(), "
+             "removing a mouse tracker...",
+             this));
+    mMouseTrackers.Clear();
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::ReleaseTSFObjects() completed", this));
+}
+
+STDMETHODIMP
+TSFTextStore::QueryInterface(REFIID riid, void** ppv) {
+  *ppv = nullptr;
+  if ((IID_IUnknown == riid) || (IID_ITextStoreACP == riid)) {
+    *ppv = static_cast<ITextStoreACP*>(this);
+  } else if (IID_ITfContextOwnerCompositionSink == riid) {
+    *ppv = static_cast<ITfContextOwnerCompositionSink*>(this);
+  } else if (IID_ITfMouseTrackerACP == riid) {
+    *ppv = static_cast<ITfMouseTrackerACP*>(this);
+  }
+  if (*ppv) {
+    AddRef();
+    return S_OK;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Error,
+          ("0x%p TSFTextStore::QueryInterface() FAILED, riid=%s", this,
+           GetRIIDNameStr(riid).get()));
+  return E_NOINTERFACE;
+}
+
+STDMETHODIMP
+TSFTextStore::AdviseSink(REFIID riid, IUnknown* punk, DWORD dwMask) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p TSFTextStore::AdviseSink(riid=%s, punk=0x%p, dwMask=%s), "
+       "mSink=0x%p, mSinkMask=%s",
+       this, GetRIIDNameStr(riid).get(), punk, GetSinkMaskNameStr(dwMask).get(),
+       mSink.get(), GetSinkMaskNameStr(mSinkMask).get()));
+
+  if (!punk) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::AdviseSink() FAILED due to the null punk",
+             this));
+    return E_UNEXPECTED;
+  }
+
+  if (IID_ITextStoreACPSink != riid) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::AdviseSink() FAILED due to "
+             "unsupported interface",
+             this));
+    return E_INVALIDARG;  // means unsupported interface.
+  }
+
+  if (!mSink) {
+    // Install sink
+    punk->QueryInterface(IID_ITextStoreACPSink, getter_AddRefs(mSink));
+    if (!mSink) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::AdviseSink() FAILED due to "
+               "punk not having the interface",
+               this));
+      return E_UNEXPECTED;
+    }
+  } else {
+    // If sink is already installed we check to see if they are the same
+    // Get IUnknown from both sides for comparison
+    RefPtr<IUnknown> comparison1, comparison2;
+    punk->QueryInterface(IID_IUnknown, getter_AddRefs(comparison1));
+    mSink->QueryInterface(IID_IUnknown, getter_AddRefs(comparison2));
+    if (comparison1 != comparison2) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::AdviseSink() FAILED due to "
+               "the sink being different from the stored sink",
+               this));
+      return CONNECT_E_ADVISELIMIT;
+    }
+  }
+  // Update mask either for a new sink or an existing sink
+  mSinkMask = dwMask;
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::UnadviseSink(IUnknown* punk) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::UnadviseSink(punk=0x%p), mSink=0x%p", this, punk,
+           mSink.get()));
+
+  if (!punk) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::UnadviseSink() FAILED due to the null punk",
+             this));
+    return E_INVALIDARG;
+  }
+  if (!mSink) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::UnadviseSink() FAILED due to "
+             "any sink not stored",
+             this));
+    return CONNECT_E_NOCONNECTION;
+  }
+  // Get IUnknown from both sides for comparison
+  RefPtr<IUnknown> comparison1, comparison2;
+  punk->QueryInterface(IID_IUnknown, getter_AddRefs(comparison1));
+  mSink->QueryInterface(IID_IUnknown, getter_AddRefs(comparison2));
+  // Unadvise only if sinks are the same
+  if (comparison1 != comparison2) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::UnadviseSink() FAILED due to "
+             "the sink being different from the stored sink",
+             this));
+    return CONNECT_E_NOCONNECTION;
+  }
+  mSink = nullptr;
+  mSinkMask = 0;
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::RequestLock(DWORD dwLockFlags, HRESULT* phrSession) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::RequestLock(dwLockFlags=%s, phrSession=0x%p), "
+           "mLock=%s, mDestroyed=%s",
+           this, GetLockFlagNameStr(dwLockFlags).get(), phrSession,
+           GetLockFlagNameStr(mLock).get(), GetBoolName(mDestroyed)));
+
+  if (!mSink) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RequestLock() FAILED due to "
+             "any sink not stored",
+             this));
+    return E_FAIL;
+  }
+  if (mDestroyed &&
+      (mContentForTSF.isNothing() || mSelectionForTSF.isNothing())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RequestLock() FAILED due to "
+             "being destroyed and no information of the contents",
+             this));
+    return E_FAIL;
+  }
+  if (!phrSession) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RequestLock() FAILED due to "
+             "null phrSession",
+             this));
+    return E_INVALIDARG;
+  }
+
+  if (!mLock) {
+    // put on lock
+    mLock = dwLockFlags & (~TS_LF_SYNC);
+    MOZ_LOG(
+        gIMELog, LogLevel::Info,
+        ("0x%p   Locking (%s) >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"
+         ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>",
+         this, GetLockFlagNameStr(mLock).get()));
+    // Don't release this instance during this lock because this is called by
+    // TSF but they don't grab us during this call.
+    RefPtr<TSFTextStore> kungFuDeathGrip(this);
+    RefPtr<ITextStoreACPSink> sink = mSink;
+    *phrSession = sink->OnLockGranted(mLock);
+    MOZ_LOG(
+        gIMELog, LogLevel::Info,
+        ("0x%p   Unlocked (%s) <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<"
+         "<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<",
+         this, GetLockFlagNameStr(mLock).get()));
+    DidLockGranted();
+    while (mLockQueued) {
+      mLock = mLockQueued;
+      mLockQueued = 0;
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   Locking for the request in the queue (%s) >>>>>>>>>>>>>>"
+               ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>"
+               ">>>>>",
+               this, GetLockFlagNameStr(mLock).get()));
+      sink->OnLockGranted(mLock);
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   Unlocked (%s) <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<"
+               "<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<"
+               "<<<<<",
+               this, GetLockFlagNameStr(mLock).get()));
+      DidLockGranted();
+    }
+
+    // The document is now completely unlocked.
+    mLock = 0;
+
+    MaybeFlushPendingNotifications();
+
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::RequestLock() succeeded: *phrSession=%s",
+             this, GetTextStoreReturnValueName(*phrSession)));
+    return S_OK;
+  }
+
+  // only time when reentrant lock is allowed is when caller holds a
+  // read-only lock and is requesting an async write lock
+  if (IsReadLocked() && !IsReadWriteLocked() && IsReadWriteLock(dwLockFlags) &&
+      !(dwLockFlags & TS_LF_SYNC)) {
+    *phrSession = TS_S_ASYNC;
+    mLockQueued = dwLockFlags & (~TS_LF_SYNC);
+
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::RequestLock() stores the request in the "
+             "queue, *phrSession=TS_S_ASYNC",
+             this));
+    return S_OK;
+  }
+
+  // no more locks allowed
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::RequestLock() didn't allow to lock, "
+           "*phrSession=TS_E_SYNCHRONOUS",
+           this));
+  *phrSession = TS_E_SYNCHRONOUS;
+  return E_FAIL;
+}
+
+void TSFTextStore::DidLockGranted() {
+  if (IsReadWriteLocked()) {
+    // FreeCJ (TIP for Traditional Chinese) calls SetSelection() to set caret
+    // to the start of composition string and insert a full width space for
+    // a placeholder with a call of SetText().  After that, it calls
+    // OnUpdateComposition() without new range.  Therefore, let's record the
+    // composition update information here.
+    CompleteLastActionIfStillIncomplete();
+
+    FlushPendingActions();
+  }
+
+  // If the widget has gone, we don't need to notify anything.
+  if (mDestroyed || !mWidget || mWidget->Destroyed()) {
+    mPendingSelectionChangeData.reset();
+    mHasReturnedNoLayoutError = false;
+  }
+}
+
+void TSFTextStore::DispatchEvent(WidgetGUIEvent& aEvent) {
+  if (NS_WARN_IF(!mWidget) || NS_WARN_IF(mWidget->Destroyed())) {
+    return;
+  }
+  // If the event isn't a query content event, the event may be handled
+  // asynchronously.  So, we should put off to answer from GetTextExt() etc.
+  if (!aEvent.AsQueryContentEvent()) {
+    mDeferNotifyingTSFUntilNextUpdate = true;
+  }
+  mWidget->DispatchWindowEvent(aEvent);
+}
+
+void TSFTextStore::FlushPendingActions() {
+  if (!mWidget || mWidget->Destroyed()) {
+    // Note that don't clear mContentForTSF because TIP may try to commit
+    // composition with a document lock.  In such case, TSFTextStore needs to
+    // behave as expected by TIP.
+    mPendingActions.Clear();
+    mPendingSelectionChangeData.reset();
+    mHasReturnedNoLayoutError = false;
+    return;
+  }
+
+  // Some TIP may request lock but does nothing during the lock.  In such case,
+  // this should do nothing.  For example, when MS-IME for Japanese is active
+  // and we're inactivating, this case occurs and causes different behavior
+  // from the other TIPs.
+  if (mPendingActions.IsEmpty()) {
+    return;
+  }
+
+  RefPtr<nsWindow> widget(mWidget);
+  nsresult rv = mDispatcher->BeginNativeInputTransaction();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::FlushPendingActions() "
+             "FAILED due to BeginNativeInputTransaction() failure",
+             this));
+    return;
+  }
+  for (uint32_t i = 0; i < mPendingActions.Length(); i++) {
+    PendingAction& action = mPendingActions[i];
+    switch (action.mType) {
+      case PendingAction::Type::eKeyboardEvent:
+        if (mDestroyed) {
+          MOZ_LOG(
+              gIMELog, LogLevel::Warning,
+              ("0x%p   TSFTextStore::FlushPendingActions() "
+               "IGNORED pending KeyboardEvent(%s) due to already destroyed",
+               this,
+               action.mKeyMsg.message == WM_KEYDOWN ? "eKeyDown" : "eKeyUp"));
+        }
+        MOZ_DIAGNOSTIC_ASSERT(action.mKeyMsg.message == WM_KEYDOWN ||
+                              action.mKeyMsg.message == WM_KEYUP);
+        DispatchKeyboardEventAsProcessedByIME(action.mKeyMsg);
+        if (!widget || widget->Destroyed()) {
+          break;
+        }
+        break;
+      case PendingAction::Type::eCompositionStart: {
+        MOZ_LOG(gIMELog, LogLevel::Debug,
+                ("0x%p   TSFTextStore::FlushPendingActions() "
+                 "flushing Type::eCompositionStart={ mSelectionStart=%ld, "
+                 "mSelectionLength=%ld }, mDestroyed=%s",
+                 this, action.mSelectionStart, action.mSelectionLength,
+                 GetBoolName(mDestroyed)));
+
+        if (mDestroyed) {
+          MOZ_LOG(gIMELog, LogLevel::Warning,
+                  ("0x%p   TSFTextStore::FlushPendingActions() "
+                   "IGNORED pending compositionstart due to already destroyed",
+                   this));
+          break;
+        }
+
+        if (action.mAdjustSelection) {
+          // Select composition range so the new composition replaces the range
+          WidgetSelectionEvent selectionSet(true, eSetSelection, widget);
+          widget->InitEvent(selectionSet);
+          selectionSet.mOffset = static_cast<uint32_t>(action.mSelectionStart);
+          selectionSet.mLength = static_cast<uint32_t>(action.mSelectionLength);
+          selectionSet.mReversed = false;
+          selectionSet.mExpandToClusterBoundary =
+              TSFStaticSink::ActiveTIP() !=
+                  TextInputProcessorID::eKeymanDesktop &&
+              StaticPrefs::
+                  intl_tsf_hack_extend_setting_selection_range_to_cluster_boundaries();
+          DispatchEvent(selectionSet);
+          if (!selectionSet.mSucceeded) {
+            MOZ_LOG(gIMELog, LogLevel::Error,
+                    ("0x%p   TSFTextStore::FlushPendingActions() "
+                     "FAILED due to eSetSelection failure",
+                     this));
+            break;
+          }
+        }
+
+        // eCompositionStart always causes
+        // NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED.  Therefore, we should
+        // wait to clear mContentForTSF until it's notified.
+        mDeferClearingContentForTSF = true;
+
+        MOZ_LOG(gIMELog, LogLevel::Debug,
+                ("0x%p   TSFTextStore::FlushPendingActions() "
+                 "dispatching compositionstart event...",
+                 this));
+        WidgetEventTime eventTime = widget->CurrentMessageWidgetEventTime();
+        nsEventStatus status;
+        rv = mDispatcher->StartComposition(status, &eventTime);
+        if (NS_WARN_IF(NS_FAILED(rv))) {
+          MOZ_LOG(gIMELog, LogLevel::Error,
+                  ("0x%p   TSFTextStore::FlushPendingActions() "
+                   "FAILED to dispatch compositionstart event, "
+                   "IsHandlingCompositionInContent()=%s",
+                   this, GetBoolName(IsHandlingCompositionInContent())));
+          // XXX Is this right? If there is a composition in content,
+          //     shouldn't we wait NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED?
+          mDeferClearingContentForTSF = !IsHandlingCompositionInContent();
+        }
+        if (!widget || widget->Destroyed()) {
+          break;
+        }
+        break;
+      }
+      case PendingAction::Type::eCompositionUpdate: {
+        MOZ_LOG(gIMELog, LogLevel::Debug,
+                ("0x%p   TSFTextStore::FlushPendingActions() "
+                 "flushing Type::eCompositionUpdate={ mData=\"%s\", "
+                 "mRanges=0x%p, mRanges->Length()=%zu }",
+                 this, GetEscapedUTF8String(action.mData).get(),
+                 action.mRanges.get(),
+                 action.mRanges ? action.mRanges->Length() : 0));
+
+        // eCompositionChange causes a DOM text event, the IME will be notified
+        // of NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED.  In this case, we
+        // should not clear mContentForTSF until we notify the IME of the
+        // composition update.
+        mDeferClearingContentForTSF = true;
+
+        rv = mDispatcher->SetPendingComposition(action.mData, action.mRanges);
+        if (NS_WARN_IF(NS_FAILED(rv))) {
+          MOZ_LOG(gIMELog, LogLevel::Error,
+                  ("0x%p   TSFTextStore::FlushPendingActions() "
+                   "FAILED to setting pending composition... "
+                   "IsHandlingCompositionInContent()=%s",
+                   this, GetBoolName(IsHandlingCompositionInContent())));
+          // XXX Is this right? If there is a composition in content,
+          //     shouldn't we wait NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED?
+          mDeferClearingContentForTSF = !IsHandlingCompositionInContent();
+        } else {
+          MOZ_LOG(gIMELog, LogLevel::Debug,
+                  ("0x%p   TSFTextStore::FlushPendingActions() "
+                   "dispatching compositionchange event...",
+                   this));
+          WidgetEventTime eventTime = widget->CurrentMessageWidgetEventTime();
+          nsEventStatus status;
+          rv = mDispatcher->FlushPendingComposition(status, &eventTime);
+          if (NS_WARN_IF(NS_FAILED(rv))) {
+            MOZ_LOG(gIMELog, LogLevel::Error,
+                    ("0x%p   TSFTextStore::FlushPendingActions() "
+                     "FAILED to dispatch compositionchange event, "
+                     "IsHandlingCompositionInContent()=%s",
+                     this, GetBoolName(IsHandlingCompositionInContent())));
+            // XXX Is this right? If there is a composition in content,
+            //     shouldn't we wait NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED?
+            mDeferClearingContentForTSF = !IsHandlingCompositionInContent();
+          }
+          // Be aware, the mWidget might already have been destroyed.
+        }
+        break;
+      }
+      case PendingAction::Type::eCompositionEnd: {
+        MOZ_LOG(gIMELog, LogLevel::Debug,
+                ("0x%p   TSFTextStore::FlushPendingActions() "
+                 "flushing Type::eCompositionEnd={ mData=\"%s\" }",
+                 this, GetEscapedUTF8String(action.mData).get()));
+
+        // Dispatching eCompositionCommit causes a DOM text event, then,
+        // the IME will be notified of NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED
+        // when focused content actually handles the event.  For example,
+        // when focused content is in a remote process, it's sent when
+        // all dispatched composition events have been handled in the remote
+        // process.  So, until then, we don't have newer content information.
+        // Therefore, we need to put off to clear mContentForTSF.
+        mDeferClearingContentForTSF = true;
+
+        MOZ_LOG(gIMELog, LogLevel::Debug,
+                ("0x%p   TSFTextStore::FlushPendingActions(), "
+                 "dispatching compositioncommit event...",
+                 this));
+        WidgetEventTime eventTime = widget->CurrentMessageWidgetEventTime();
+        nsEventStatus status;
+        rv = mDispatcher->CommitComposition(status, &action.mData, &eventTime);
+        if (NS_WARN_IF(NS_FAILED(rv))) {
+          MOZ_LOG(gIMELog, LogLevel::Error,
+                  ("0x%p   TSFTextStore::FlushPendingActions() "
+                   "FAILED to dispatch compositioncommit event, "
+                   "IsHandlingCompositionInContent()=%s",
+                   this, GetBoolName(IsHandlingCompositionInContent())));
+          // XXX Is this right? If there is a composition in content,
+          //     shouldn't we wait NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED?
+          mDeferClearingContentForTSF = !IsHandlingCompositionInContent();
+        }
+        break;
+      }
+      case PendingAction::Type::eSetSelection: {
+        MOZ_LOG(
+            gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::FlushPendingActions() "
+             "flushing Type::eSetSelection={ mSelectionStart=%ld, "
+             "mSelectionLength=%ld, mSelectionReversed=%s }, "
+             "mDestroyed=%s",
+             this, action.mSelectionStart, action.mSelectionLength,
+             GetBoolName(action.mSelectionReversed), GetBoolName(mDestroyed)));
+
+        if (mDestroyed) {
+          MOZ_LOG(gIMELog, LogLevel::Warning,
+                  ("0x%p   TSFTextStore::FlushPendingActions() "
+                   "IGNORED pending selectionset due to already destroyed",
+                   this));
+          break;
+        }
+
+        WidgetSelectionEvent selectionSet(true, eSetSelection, widget);
+        selectionSet.mOffset = static_cast<uint32_t>(action.mSelectionStart);
+        selectionSet.mLength = static_cast<uint32_t>(action.mSelectionLength);
+        selectionSet.mReversed = action.mSelectionReversed;
+        selectionSet.mExpandToClusterBoundary =
+            TSFStaticSink::ActiveTIP() !=
+                TextInputProcessorID::eKeymanDesktop &&
+            StaticPrefs::
+                intl_tsf_hack_extend_setting_selection_range_to_cluster_boundaries();
+        DispatchEvent(selectionSet);
+        if (!selectionSet.mSucceeded) {
+          MOZ_LOG(gIMELog, LogLevel::Error,
+                  ("0x%p   TSFTextStore::FlushPendingActions() "
+                   "FAILED due to eSetSelection failure",
+                   this));
+          break;
+        }
+        break;
+      }
+      default:
+        MOZ_CRASH("unexpected action type");
+    }
+
+    if (widget && !widget->Destroyed()) {
+      continue;
+    }
+
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::FlushPendingActions(), "
+             "qutting since the mWidget has gone",
+             this));
+    break;
+  }
+  mPendingActions.Clear();
+}
+
+void TSFTextStore::MaybeFlushPendingNotifications() {
+  if (mDeferNotifyingTSF) {
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::MaybeFlushPendingNotifications(), "
+             "putting off flushing pending notifications due to initializing "
+             "something...",
+             this));
+    return;
+  }
+
+  if (IsReadLocked()) {
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::MaybeFlushPendingNotifications(), "
+             "putting off flushing pending notifications due to being the "
+             "document locked...",
+             this));
+    return;
+  }
+
+  if (mDeferCommittingComposition) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::MaybeFlushPendingNotifications(), "
+             "calling TSFTextStore::CommitCompositionInternal(false)...",
+             this));
+    mDeferCommittingComposition = mDeferCancellingComposition = false;
+    CommitCompositionInternal(false);
+  } else if (mDeferCancellingComposition) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::MaybeFlushPendingNotifications(), "
+             "calling TSFTextStore::CommitCompositionInternal(true)...",
+             this));
+    mDeferCommittingComposition = mDeferCancellingComposition = false;
+    CommitCompositionInternal(true);
+  }
+
+  if (mDeferNotifyingTSFUntilNextUpdate) {
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::MaybeFlushPendingNotifications(), "
+             "putting off flushing pending notifications due to being "
+             "dispatching events...",
+             this));
+    return;
+  }
+
+  if (mPendingDestroy) {
+    Destroy();
+    return;
+  }
+
+  if (mDestroyed) {
+    // If it's already been destroyed completely, this shouldn't notify TSF of
+    // anything anymore.
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::MaybeFlushPendingNotifications(), "
+             "does nothing because this has already destroyed completely...",
+             this));
+    return;
+  }
+
+  if (!mDeferClearingContentForTSF && mContentForTSF.isSome()) {
+    mContentForTSF.reset();
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::MaybeFlushPendingNotifications(), "
+             "mContentForTSF is set to `Nothing`",
+             this));
+  }
+
+  // When there is no cached content, we can sync actual contents and TSF/TIP
+  // expecting contents.
+  RefPtr<TSFTextStore> kungFuDeathGrip = this;
+  Unused << kungFuDeathGrip;
+  if (mContentForTSF.isNothing()) {
+    if (mPendingTextChangeData.IsValid()) {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   TSFTextStore::MaybeFlushPendingNotifications(), "
+               "calling TSFTextStore::NotifyTSFOfTextChange()...",
+               this));
+      NotifyTSFOfTextChange();
+    }
+    if (mPendingSelectionChangeData.isSome()) {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   TSFTextStore::MaybeFlushPendingNotifications(), "
+               "calling TSFTextStore::NotifyTSFOfSelectionChange()...",
+               this));
+      NotifyTSFOfSelectionChange();
+    }
+  }
+
+  if (mHasReturnedNoLayoutError) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::MaybeFlushPendingNotifications(), "
+             "calling TSFTextStore::NotifyTSFOfLayoutChange()...",
+             this));
+    NotifyTSFOfLayoutChange();
+  }
+}
+
+void TSFTextStore::MaybeDispatchKeyboardEventAsProcessedByIME() {
+  // If we've already been destroyed, we cannot do anything.
+  if (mDestroyed) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Debug,
+        ("0x%p   TSFTextStore::MaybeDispatchKeyboardEventAsProcessedByIME(), "
+         "does nothing because it's already been destroyed",
+         this));
+    return;
+  }
+
+  // If we're not handling key message or we've already dispatched a keyboard
+  // event for the handling key message, we should do nothing anymore.
+  if (!sHandlingKeyMsg || sIsKeyboardEventDispatched) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Debug,
+        ("0x%p   TSFTextStore::MaybeDispatchKeyboardEventAsProcessedByIME(), "
+         "does nothing because not necessary to dispatch keyboard event",
+         this));
+    return;
+  }
+
+  sIsKeyboardEventDispatched = true;
+  // If the document is locked, just adding the task to dispatching an event
+  // to the queue.
+  if (IsReadLocked()) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Debug,
+        ("0x%p   TSFTextStore::MaybeDispatchKeyboardEventAsProcessedByIME(), "
+         "adding to dispatch a keyboard event into the queue...",
+         this));
+    PendingAction* action = mPendingActions.AppendElement();
+    action->mType = PendingAction::Type::eKeyboardEvent;
+    memcpy(&action->mKeyMsg, sHandlingKeyMsg, sizeof(MSG));
+    return;
+  }
+
+  // Otherwise, dispatch a keyboard event.
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::MaybeDispatchKeyboardEventAsProcessedByIME(), "
+           "trying to dispatch a keyboard event...",
+           this));
+  DispatchKeyboardEventAsProcessedByIME(*sHandlingKeyMsg);
+}
+
+void TSFTextStore::DispatchKeyboardEventAsProcessedByIME(const MSG& aMsg) {
+  MOZ_ASSERT(mWidget);
+  MOZ_ASSERT(!mWidget->Destroyed());
+  MOZ_ASSERT(!mDestroyed);
+
+  ModifierKeyState modKeyState;
+  MSG msg(aMsg);
+  msg.wParam = VK_PROCESSKEY;
+  NativeKey nativeKey(mWidget, msg, modKeyState);
+  switch (aMsg.message) {
+    case WM_KEYDOWN:
+      MOZ_LOG(gIMELog, LogLevel::Debug,
+              ("0x%p   TSFTextStore::DispatchKeyboardEventAsProcessedByIME(), "
+               "dispatching an eKeyDown event...",
+               this));
+      nativeKey.HandleKeyDownMessage();
+      break;
+    case WM_KEYUP:
+      MOZ_LOG(gIMELog, LogLevel::Debug,
+              ("0x%p   TSFTextStore::DispatchKeyboardEventAsProcessedByIME(), "
+               "dispatching an eKeyUp event...",
+               this));
+      nativeKey.HandleKeyUpMessage();
+      break;
+    default:
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::DispatchKeyboardEventAsProcessedByIME(), "
+               "ERROR, it doesn't handle the message",
+               this));
+      break;
+  }
+}
+
+STDMETHODIMP
+TSFTextStore::GetStatus(TS_STATUS* pdcs) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::GetStatus(pdcs=0x%p)", this, pdcs));
+
+  if (!pdcs) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetStatus() FAILED due to null pdcs", this));
+    return E_INVALIDARG;
+  }
+  // We manage on-screen keyboard by own.
+  pdcs->dwDynamicFlags = TS_SD_INPUTPANEMANUALDISPLAYENABLE;
+  // we use a "flat" text model for TSF support so no hidden text
+  pdcs->dwStaticFlags = TS_SS_NOHIDDENTEXT;
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::QueryInsert(LONG acpTestStart, LONG acpTestEnd, ULONG cch,
+                          LONG* pacpResultStart, LONG* pacpResultEnd) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p TSFTextStore::QueryInsert(acpTestStart=%ld, "
+       "acpTestEnd=%ld, cch=%lu, pacpResultStart=0x%p, pacpResultEnd=0x%p)",
+       this, acpTestStart, acpTestEnd, cch, pacpResultStart, pacpResultEnd));
+
+  if (!pacpResultStart || !pacpResultEnd) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::QueryInsert() FAILED due to "
+             "the null argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  if (acpTestStart < 0 || acpTestStart > acpTestEnd) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::QueryInsert() FAILED due to "
+             "wrong argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  // XXX need to adjust to cluster boundary
+  // Assume we are given good offsets for now
+  if (mComposition.isNothing() &&
+      ((StaticPrefs::
+            intl_tsf_hack_ms_traditional_chinese_query_insert_result() &&
+        TSFStaticSink::IsMSChangJieOrMSQuickActive()) ||
+       (StaticPrefs::
+            intl_tsf_hack_ms_simplified_chinese_query_insert_result() &&
+        TSFStaticSink::IsMSPinyinOrMSWubiActive()))) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   TSFTextStore::QueryInsert() WARNING using different "
+             "result for the TIP",
+             this));
+    // Chinese TIPs of Microsoft assume that QueryInsert() returns selected
+    // range which should be removed.
+    *pacpResultStart = acpTestStart;
+    *pacpResultEnd = acpTestEnd;
+  } else {
+    *pacpResultStart = acpTestStart;
+    *pacpResultEnd = acpTestStart + cch;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p  TSFTextStore::QueryInsert() succeeded: "
+           "*pacpResultStart=%ld, *pacpResultEnd=%ld)",
+           this, *pacpResultStart, *pacpResultEnd));
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::GetSelection(ULONG ulIndex, ULONG ulCount,
+                           TS_SELECTION_ACP* pSelection, ULONG* pcFetched) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::GetSelection(ulIndex=%lu, ulCount=%lu, "
+           "pSelection=0x%p, pcFetched=0x%p)",
+           this, ulIndex, ulCount, pSelection, pcFetched));
+
+  if (!IsReadLocked()) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Error,
+        ("0x%p   TSFTextStore::GetSelection() FAILED due to not locked", this));
+    return TS_E_NOLOCK;
+  }
+  if (!ulCount || !pSelection || !pcFetched) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetSelection() FAILED due to "
+             "null argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  *pcFetched = 0;
+
+  if (ulIndex != static_cast<ULONG>(TS_DEFAULT_SELECTION) && ulIndex != 0) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetSelection() FAILED due to "
+             "unsupported selection",
+             this));
+    return TS_E_NOSELECTION;
+  }
+
+  Maybe<Selection>& selectionForTSF = SelectionForTSF();
+  if (selectionForTSF.isNothing()) {
+    if (DoNotReturnErrorFromGetSelection()) {
+      *pSelection = Selection::EmptyACP();
+      *pcFetched = 1;
+      MOZ_LOG(
+          gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::GetSelection() returns fake selection range "
+           "for avoiding a crash in TSF, *pSelection=%s",
+           this, mozilla::ToString(*pSelection).c_str()));
+      return S_OK;
+    }
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetSelection() FAILED due to "
+             "SelectionForTSF() failure",
+             this));
+    return E_FAIL;
+  }
+  if (!selectionForTSF->HasRange()) {
+    *pSelection = Selection::EmptyACP();
+    *pcFetched = 0;
+    return TS_E_NOSELECTION;
+  }
+  *pSelection = selectionForTSF->ACPRef();
+  *pcFetched = 1;
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::GetSelection() succeeded, *pSelection=%s",
+           this, mozilla::ToString(*pSelection).c_str()));
+  return S_OK;
+}
+
+// static
+bool TSFTextStore::DoNotReturnErrorFromGetSelection() {
+  // There is a crash bug of TSF if we return error from GetSelection().
+  // That was introduced in Anniversary Update (build 14393, see bug 1312302)
+  // TODO: We should avoid to run this hack on fixed builds.  When we get
+  //       exact build number, we should get back here.
+  static bool sTSFMayCrashIfGetSelectionReturnsError =
+      IsWin10AnniversaryUpdateOrLater();
+  return sTSFMayCrashIfGetSelectionReturnsError;
+}
+
+Maybe<TSFTextStore::Content>& TSFTextStore::ContentForTSF() {
+  // This should be called when the document is locked or the content hasn't
+  // been abandoned yet.
+  if (NS_WARN_IF(!IsReadLocked() && mContentForTSF.isNothing())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::ContentForTSF(), FAILED, due to "
+             "called wrong timing, IsReadLocked()=%s, mContentForTSF=Nothing",
+             this, GetBoolName(IsReadLocked())));
+    return mContentForTSF;
+  }
+
+  Maybe<Selection>& selectionForTSF = SelectionForTSF();
+  if (selectionForTSF.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::ContentForTSF(), FAILED, due to "
+             "SelectionForTSF() failure",
+             this));
+    mContentForTSF.reset();
+    return mContentForTSF;
+  }
+
+  if (mContentForTSF.isNothing()) {
+    MOZ_DIAGNOSTIC_ASSERT(
+        !mIsInitializingContentForTSF,
+        "TSFTextStore::ContentForTSF() shouldn't be called recursively");
+
+    AutoNotifyingTSFBatch deferNotifyingTSF(*this);
+    AutoRestore<bool> saveInitializingContetTSF(mIsInitializingContentForTSF);
+    mIsInitializingContentForTSF = true;
+
+    nsString text;  // Don't use auto string for avoiding to copy long string.
+    if (NS_WARN_IF(!GetCurrentText(text))) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::ContentForTSF(), FAILED, due to "
+               "GetCurrentText() failure",
+               this));
+      return mContentForTSF;
+    }
+
+    MOZ_DIAGNOSTIC_ASSERT(mContentForTSF.isNothing(),
+                          "How was it initialized recursively?");
+    mContentForTSF.reset();  // For avoiding crash in release channel
+    mContentForTSF.emplace(*this, text);
+    // Basically, the cached content which is expected by TSF/TIP should be
+    // cleared after active composition is committed or the document lock is
+    // unlocked.  However, in e10s mode, content will be modified
+    // asynchronously.  In such case, mDeferClearingContentForTSF may be
+    // true until whole dispatched events are handled by the focused editor.
+    mDeferClearingContentForTSF = false;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::ContentForTSF(): mContentForTSF=%s", this,
+           mozilla::ToString(mContentForTSF).c_str()));
+
+  return mContentForTSF;
+}
+
+bool TSFTextStore::CanAccessActualContentDirectly() const {
+  if (mContentForTSF.isNothing() || mSelectionForTSF.isNothing()) {
+    return true;
+  }
+
+  // If the cached content has been changed by something except composition,
+  // the content cache may be different from actual content.
+  if (mPendingTextChangeData.IsValid() &&
+      !mPendingTextChangeData.mCausedOnlyByComposition) {
+    return false;
+  }
+
+  // If the cached selection isn't changed, cached content and actual content
+  // should be same.
+  if (mPendingSelectionChangeData.isNothing()) {
+    return true;
+  }
+
+  return mSelectionForTSF->EqualsExceptDirection(*mPendingSelectionChangeData);
+}
+
+bool TSFTextStore::GetCurrentText(nsAString& aTextContent) {
+  if (mContentForTSF.isSome()) {
+    aTextContent = mContentForTSF->TextRef();
+    return true;
+  }
+
+  MOZ_ASSERT(!mDestroyed);
+  MOZ_ASSERT(mWidget && !mWidget->Destroyed());
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::GetCurrentText(): "
+           "retrieving text from the content...",
+           this));
+
+  WidgetQueryContentEvent queryTextContentEvent(true, eQueryTextContent,
+                                                mWidget);
+  queryTextContentEvent.InitForQueryTextContent(0, UINT32_MAX);
+  mWidget->InitEvent(queryTextContentEvent);
+  DispatchEvent(queryTextContentEvent);
+  if (NS_WARN_IF(queryTextContentEvent.Failed())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetCurrentText(), FAILED, due to "
+             "eQueryTextContent failure",
+             this));
+    aTextContent.Truncate();
+    return false;
+  }
+
+  aTextContent = queryTextContentEvent.mReply->DataRef();
+  return true;
+}
+
+Maybe<TSFTextStore::Selection>& TSFTextStore::SelectionForTSF() {
+  if (mSelectionForTSF.isNothing()) {
+    MOZ_ASSERT(!mDestroyed);
+    // If the window has never been available, we should crash since working
+    // with broken values may make TIP confused.
+    if (!mWidget || mWidget->Destroyed()) {
+      MOZ_ASSERT_UNREACHABLE("There should be non-destroyed widget");
+    }
+
+    MOZ_DIAGNOSTIC_ASSERT(
+        !mIsInitializingSelectionForTSF,
+        "TSFTextStore::SelectionForTSF() shouldn't be called recursively");
+
+    AutoNotifyingTSFBatch deferNotifyingTSF(*this);
+    AutoRestore<bool> saveInitializingSelectionForTSF(
+        mIsInitializingSelectionForTSF);
+    mIsInitializingSelectionForTSF = true;
+
+    WidgetQueryContentEvent querySelectedTextEvent(true, eQuerySelectedText,
+                                                   mWidget);
+    mWidget->InitEvent(querySelectedTextEvent);
+    DispatchEvent(querySelectedTextEvent);
+    if (NS_WARN_IF(querySelectedTextEvent.Failed())) {
+      return mSelectionForTSF;
+    }
+    MOZ_DIAGNOSTIC_ASSERT(mSelectionForTSF.isNothing(),
+                          "How was it initialized recursively?");
+    mSelectionForTSF = Some(Selection(querySelectedTextEvent));
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::SelectionForTSF() succeeded, "
+           "mSelectionForTSF=%s",
+           this, ToString(mSelectionForTSF).c_str()));
+
+  return mSelectionForTSF;
+}
+
+static HRESULT GetRangeExtent(ITfRange* aRange, LONG* aStart, LONG* aLength) {
+  RefPtr<ITfRangeACP> rangeACP;
+  aRange->QueryInterface(IID_ITfRangeACP, getter_AddRefs(rangeACP));
+  NS_ENSURE_TRUE(rangeACP, E_FAIL);
+  return rangeACP->GetExtent(aStart, aLength);
+}
+
+static TextRangeType GetGeckoSelectionValue(TF_DISPLAYATTRIBUTE& aDisplayAttr) {
+  switch (aDisplayAttr.bAttr) {
+    case TF_ATTR_TARGET_CONVERTED:
+      return TextRangeType::eSelectedClause;
+    case TF_ATTR_CONVERTED:
+      return TextRangeType::eConvertedClause;
+    case TF_ATTR_TARGET_NOTCONVERTED:
+      return TextRangeType::eSelectedRawClause;
+    default:
+      return TextRangeType::eRawClause;
+  }
+}
+
+HRESULT
+TSFTextStore::GetDisplayAttribute(ITfProperty* aAttrProperty, ITfRange* aRange,
+                                  TF_DISPLAYATTRIBUTE* aResult) {
+  NS_ENSURE_TRUE(aAttrProperty, E_FAIL);
+  NS_ENSURE_TRUE(aRange, E_FAIL);
+  NS_ENSURE_TRUE(aResult, E_FAIL);
+
+  HRESULT hr;
+
+  if (MOZ_LOG_TEST(gIMELog, LogLevel::Debug)) {
+    LONG start = 0, length = 0;
+    hr = GetRangeExtent(aRange, &start, &length);
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::GetDisplayAttribute(): "
+             "GetDisplayAttribute range=%ld-%ld (hr=%s)",
+             this, start - mComposition->StartOffset(),
+             start - mComposition->StartOffset() + length,
+             GetCommonReturnValueName(hr)));
+  }
+
+  VARIANT propValue;
+  ::VariantInit(&propValue);
+  hr = aAttrProperty->GetValue(TfEditCookie(mEditCookie), aRange, &propValue);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetDisplayAttribute() FAILED due to "
+             "ITfProperty::GetValue() failed",
+             this));
+    return hr;
+  }
+  if (VT_I4 != propValue.vt) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetDisplayAttribute() FAILED due to "
+             "ITfProperty::GetValue() returns non-VT_I4 value",
+             this));
+    ::VariantClear(&propValue);
+    return E_FAIL;
+  }
+
+  RefPtr<ITfCategoryMgr> categoryMgr = GetCategoryMgr();
+  if (NS_WARN_IF(!categoryMgr)) {
+    return E_FAIL;
+  }
+  GUID guid;
+  hr = categoryMgr->GetGUID(DWORD(propValue.lVal), &guid);
+  ::VariantClear(&propValue);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetDisplayAttribute() FAILED due to "
+             "ITfCategoryMgr::GetGUID() failed",
+             this));
+    return hr;
+  }
+
+  RefPtr<ITfDisplayAttributeMgr> displayAttrMgr = GetDisplayAttributeMgr();
+  if (NS_WARN_IF(!displayAttrMgr)) {
+    return E_FAIL;
+  }
+  RefPtr<ITfDisplayAttributeInfo> info;
+  hr = displayAttrMgr->GetDisplayAttributeInfo(guid, getter_AddRefs(info),
+                                               nullptr);
+  if (FAILED(hr) || !info) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetDisplayAttribute() FAILED due to "
+             "ITfDisplayAttributeMgr::GetDisplayAttributeInfo() failed",
+             this));
+    return hr;
+  }
+
+  hr = info->GetAttributeInfo(aResult);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetDisplayAttribute() FAILED due to "
+             "ITfDisplayAttributeInfo::GetAttributeInfo() failed",
+             this));
+    return hr;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::GetDisplayAttribute() succeeded: "
+           "Result={ %s }",
+           this, GetDisplayAttrStr(*aResult).get()));
+  return S_OK;
+}
+
+HRESULT
+TSFTextStore::RestartCompositionIfNecessary(ITfRange* aRangeNew) {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::RestartCompositionIfNecessary("
+           "aRangeNew=0x%p), mComposition=%s",
+           this, aRangeNew, ToString(mComposition).c_str()));
+
+  if (mComposition.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RestartCompositionIfNecessary() FAILED "
+             "due to no composition view",
+             this));
+    return E_FAIL;
+  }
+
+  HRESULT hr;
+  RefPtr<ITfCompositionView> pComposition(mComposition->GetView());
+  RefPtr<ITfRange> composingRange(aRangeNew);
+  if (!composingRange) {
+    hr = pComposition->GetRange(getter_AddRefs(composingRange));
+    if (FAILED(hr)) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::RestartCompositionIfNecessary() "
+               "FAILED due to pComposition->GetRange() failure",
+               this));
+      return hr;
+    }
+  }
+
+  // Get starting offset of the composition
+  LONG compStart = 0, compLength = 0;
+  hr = GetRangeExtent(composingRange, &compStart, &compLength);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RestartCompositionIfNecessary() FAILED "
+             "due to GetRangeExtent() failure",
+             this));
+    return hr;
+  }
+
+  if (mComposition->StartOffset() == compStart &&
+      mComposition->Length() == compLength) {
+    return S_OK;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::RestartCompositionIfNecessary(), "
+           "restaring composition because of compostion range is changed "
+           "(range=%ld-%ld, mComposition=%s)",
+           this, compStart, compStart + compLength,
+           ToString(mComposition).c_str()));
+
+  // If the queried composition length is different from the length
+  // of our composition string, OnUpdateComposition is being called
+  // because a part of the original composition was committed.
+  hr = RestartComposition(*mComposition, pComposition, composingRange);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RestartCompositionIfNecessary() "
+             "FAILED due to RestartComposition() failure",
+             this));
+    return hr;
+  }
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Debug,
+      ("0x%p   TSFTextStore::RestartCompositionIfNecessary() succeeded", this));
+  return S_OK;
+}
+
+HRESULT TSFTextStore::RestartComposition(Composition& aCurrentComposition,
+                                         ITfCompositionView* aCompositionView,
+                                         ITfRange* aNewRange) {
+  Maybe<Selection>& selectionForTSF = SelectionForTSF();
+
+  LONG newStart, newLength;
+  HRESULT hr = GetRangeExtent(aNewRange, &newStart, &newLength);
+  LONG newEnd = newStart + newLength;
+
+  if (selectionForTSF.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RestartComposition() FAILED "
+             "due to SelectionForTSF() failure",
+             this));
+    return E_FAIL;
+  }
+
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RestartComposition() FAILED "
+             "due to GetRangeExtent() failure",
+             this));
+    return hr;
+  }
+
+  // If the new range has no overlap with the crrent range, we just commit
+  // the composition and restart new composition with the new range but
+  // current selection range should be preserved.
+  if (newStart >= aCurrentComposition.EndOffset() ||
+      newEnd <= aCurrentComposition.StartOffset()) {
+    RecordCompositionEndAction();
+    RecordCompositionStartAction(aCompositionView, newStart, newLength, true);
+    return S_OK;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::RestartComposition(aCompositionView=0x%p, "
+           "aNewRange=0x%p { newStart=%ld, newLength=%ld }), "
+           "aCurrentComposition=%s, "
+           "selectionForTSF=%s",
+           this, aCompositionView, aNewRange, newStart, newLength,
+           ToString(aCurrentComposition).c_str(),
+           ToString(selectionForTSF).c_str()));
+
+  // If the new range has an overlap with the current one, we should not commit
+  // the whole current range to avoid creating an odd undo transaction.
+  // I.e., the overlapped range which is being composed should not appear in
+  // undo transaction.
+
+  // Backup current composition data and selection data.
+  Composition oldComposition = aCurrentComposition;
+  Selection oldSelection = *selectionForTSF;
+
+  // Commit only the part of composition.
+  LONG keepComposingStartOffset =
+      std::max(oldComposition.StartOffset(), newStart);
+  LONG keepComposingEndOffset = std::min(oldComposition.EndOffset(), newEnd);
+  MOZ_ASSERT(
+      keepComposingStartOffset <= keepComposingEndOffset,
+      "Why keepComposingEndOffset is smaller than keepComposingStartOffset?");
+  LONG keepComposingLength = keepComposingEndOffset - keepComposingStartOffset;
+  // Remove the overlapped part from the commit string.
+  nsAutoString commitString(oldComposition.DataRef());
+  commitString.Cut(keepComposingStartOffset - oldComposition.StartOffset(),
+                   keepComposingLength);
+  // Update the composition string.
+  Maybe<Content>& contentForTSF = ContentForTSF();
+  if (contentForTSF.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RestartComposition() FAILED "
+             "due to ContentForTSF() failure",
+             this));
+    return E_FAIL;
+  }
+  contentForTSF->ReplaceTextWith(oldComposition.StartOffset(),
+                                 oldComposition.Length(), commitString);
+  MOZ_ASSERT(mComposition.isSome());
+  // Record a compositionupdate action for commit the part of composing string.
+  PendingAction* action = LastOrNewPendingCompositionUpdate();
+  if (mComposition.isSome()) {
+    action->mData = mComposition->DataRef();
+  }
+  action->mRanges->Clear();
+  // Note that we shouldn't append ranges when composition string
+  // is empty because it may cause TextComposition confused.
+  if (!action->mData.IsEmpty()) {
+    TextRange caretRange;
+    caretRange.mStartOffset = caretRange.mEndOffset = static_cast<uint32_t>(
+        oldComposition.StartOffset() + commitString.Length());
+    caretRange.mRangeType = TextRangeType::eCaret;
+    action->mRanges->AppendElement(caretRange);
+  }
+  action->mIncomplete = false;
+
+  // Record compositionend action.
+  RecordCompositionEndAction();
+
+  // Record compositionstart action only with the new start since this method
+  // hasn't restored composing string yet.
+  RecordCompositionStartAction(aCompositionView, newStart, 0, false);
+
+  // Restore the latest text content and selection.
+  contentForTSF->ReplaceSelectedTextWith(nsDependentSubstring(
+      oldComposition.DataRef(),
+      keepComposingStartOffset - oldComposition.StartOffset(),
+      keepComposingLength));
+  selectionForTSF = Some(oldSelection);
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::RestartComposition() succeeded, "
+           "mComposition=%s, selectionForTSF=%s",
+           this, ToString(mComposition).c_str(),
+           ToString(selectionForTSF).c_str()));
+
+  return S_OK;
+}
+
+static bool GetColor(const TF_DA_COLOR& aTSFColor, nscolor& aResult) {
+  switch (aTSFColor.type) {
+    case TF_CT_SYSCOLOR: {
+      DWORD sysColor = ::GetSysColor(aTSFColor.nIndex);
+      aResult =
+          NS_RGB(GetRValue(sysColor), GetGValue(sysColor), GetBValue(sysColor));
+      return true;
+    }
+    case TF_CT_COLORREF:
+      aResult = NS_RGB(GetRValue(aTSFColor.cr), GetGValue(aTSFColor.cr),
+                       GetBValue(aTSFColor.cr));
+      return true;
+    case TF_CT_NONE:
+    default:
+      return false;
+  }
+}
+
+static bool GetLineStyle(TF_DA_LINESTYLE aTSFLineStyle,
+                         TextRangeStyle::LineStyle& aTextRangeLineStyle) {
+  switch (aTSFLineStyle) {
+    case TF_LS_NONE:
+      aTextRangeLineStyle = TextRangeStyle::LineStyle::None;
+      return true;
+    case TF_LS_SOLID:
+      aTextRangeLineStyle = TextRangeStyle::LineStyle::Solid;
+      return true;
+    case TF_LS_DOT:
+      aTextRangeLineStyle = TextRangeStyle::LineStyle::Dotted;
+      return true;
+    case TF_LS_DASH:
+      aTextRangeLineStyle = TextRangeStyle::LineStyle::Dashed;
+      return true;
+    case TF_LS_SQUIGGLE:
+      aTextRangeLineStyle = TextRangeStyle::LineStyle::Wavy;
+      return true;
+    default:
+      return false;
+  }
+}
+
+HRESULT
+TSFTextStore::RecordCompositionUpdateAction() {
+  MOZ_LOG(
+      gIMELog, LogLevel::Debug,
+      ("0x%p   TSFTextStore::RecordCompositionUpdateAction(), mComposition=%s",
+       this, ToString(mComposition).c_str()));
+
+  if (mComposition.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RecordCompositionUpdateAction() FAILED "
+             "due to no composition view",
+             this));
+    return E_FAIL;
+  }
+
+  // Getting display attributes is *really* complicated!
+  // We first get the context and the property objects to query for
+  // attributes, but since a big range can have a variety of values for
+  // the attribute, we have to find out all the ranges that have distinct
+  // attribute values. Then we query for what the value represents through
+  // the display attribute manager and translate that to TextRange to be
+  // sent in eCompositionChange
+
+  RefPtr<ITfProperty> attrPropetry;
+  HRESULT hr =
+      mContext->GetProperty(GUID_PROP_ATTRIBUTE, getter_AddRefs(attrPropetry));
+  if (FAILED(hr) || !attrPropetry) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RecordCompositionUpdateAction() FAILED "
+             "due to mContext->GetProperty() failure",
+             this));
+    return FAILED(hr) ? hr : E_FAIL;
+  }
+
+  RefPtr<ITfRange> composingRange;
+  hr = mComposition->GetView()->GetRange(getter_AddRefs(composingRange));
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RecordCompositionUpdateAction() "
+             "FAILED due to mComposition->GetView()->GetRange() failure",
+             this));
+    return hr;
+  }
+
+  RefPtr<IEnumTfRanges> enumRanges;
+  hr = attrPropetry->EnumRanges(TfEditCookie(mEditCookie),
+                                getter_AddRefs(enumRanges), composingRange);
+  if (FAILED(hr) || !enumRanges) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RecordCompositionUpdateAction() FAILED "
+             "due to attrPropetry->EnumRanges() failure",
+             this));
+    return FAILED(hr) ? hr : E_FAIL;
+  }
+
+  // First, put the log of content and selection here.
+  Maybe<Selection>& selectionForTSF = SelectionForTSF();
+  if (selectionForTSF.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RecordCompositionUpdateAction() FAILED "
+             "due to SelectionForTSF() failure",
+             this));
+    return E_FAIL;
+  }
+
+  PendingAction* action = LastOrNewPendingCompositionUpdate();
+  action->mData = mComposition->DataRef();
+  // The ranges might already have been initialized, however, if this is
+  // called again, that means we need to overwrite the ranges with current
+  // information.
+  action->mRanges->Clear();
+
+  // Note that we shouldn't append ranges when composition string
+  // is empty because it may cause TextComposition confused.
+  if (!action->mData.IsEmpty()) {
+    TextRange newRange;
+    // No matter if we have display attribute info or not,
+    // we always pass in at least one range to eCompositionChange
+    newRange.mStartOffset = 0;
+    newRange.mEndOffset = action->mData.Length();
+    newRange.mRangeType = TextRangeType::eRawClause;
+    action->mRanges->AppendElement(newRange);
+
+    RefPtr<ITfRange> range;
+    while (enumRanges->Next(1, getter_AddRefs(range), nullptr) == S_OK) {
+      if (NS_WARN_IF(!range)) {
+        break;
+      }
+
+      LONG rangeStart = 0, rangeLength = 0;
+      if (FAILED(GetRangeExtent(range, &rangeStart, &rangeLength))) {
+        continue;
+      }
+      // The range may include out of composition string.  We should ignore
+      // outside of the composition string.
+      LONG start = std::min(std::max(rangeStart, mComposition->StartOffset()),
+                            mComposition->EndOffset());
+      LONG end = std::max(
+          std::min(rangeStart + rangeLength, mComposition->EndOffset()),
+          mComposition->StartOffset());
+      LONG length = end - start;
+      if (length < 0) {
+        MOZ_LOG(gIMELog, LogLevel::Error,
+                ("0x%p   TSFTextStore::RecordCompositionUpdateAction() "
+                 "ignores invalid range (%ld-%ld)",
+                 this, rangeStart - mComposition->StartOffset(),
+                 rangeStart - mComposition->StartOffset() + rangeLength));
+        continue;
+      }
+      if (!length) {
+        MOZ_LOG(gIMELog, LogLevel::Debug,
+                ("0x%p   TSFTextStore::RecordCompositionUpdateAction() "
+                 "ignores a range due to outside of the composition or empty "
+                 "(%ld-%ld)",
+                 this, rangeStart - mComposition->StartOffset(),
+                 rangeStart - mComposition->StartOffset() + rangeLength));
+        continue;
+      }
+
+      TextRange newRange;
+      newRange.mStartOffset =
+          static_cast<uint32_t>(start - mComposition->StartOffset());
+      // The end of the last range in the array is
+      // always kept at the end of composition
+      newRange.mEndOffset = mComposition->Length();
+
+      TF_DISPLAYATTRIBUTE attr;
+      hr = GetDisplayAttribute(attrPropetry, range, &attr);
+      if (FAILED(hr)) {
+        newRange.mRangeType = TextRangeType::eRawClause;
+      } else {
+        newRange.mRangeType = GetGeckoSelectionValue(attr);
+        if (GetColor(attr.crText, newRange.mRangeStyle.mForegroundColor)) {
+          newRange.mRangeStyle.mDefinedStyles |=
+              TextRangeStyle::DEFINED_FOREGROUND_COLOR;
+        }
+        if (GetColor(attr.crBk, newRange.mRangeStyle.mBackgroundColor)) {
+          newRange.mRangeStyle.mDefinedStyles |=
+              TextRangeStyle::DEFINED_BACKGROUND_COLOR;
+        }
+        if (GetColor(attr.crLine, newRange.mRangeStyle.mUnderlineColor)) {
+          newRange.mRangeStyle.mDefinedStyles |=
+              TextRangeStyle::DEFINED_UNDERLINE_COLOR;
+        }
+        if (GetLineStyle(attr.lsStyle, newRange.mRangeStyle.mLineStyle)) {
+          newRange.mRangeStyle.mDefinedStyles |=
+              TextRangeStyle::DEFINED_LINESTYLE;
+          newRange.mRangeStyle.mIsBoldLine = attr.fBoldLine != 0;
+        }
+      }
+
+      TextRange& lastRange = action->mRanges->LastElement();
+      if (lastRange.mStartOffset == newRange.mStartOffset) {
+        // Replace range if last range is the same as this one
+        // So that ranges don't overlap and confuse the editor
+        lastRange = newRange;
+      } else {
+        lastRange.mEndOffset = newRange.mStartOffset;
+        action->mRanges->AppendElement(newRange);
+      }
+    }
+
+    // We need to hack for Korean Input System which is Korean standard TIP.
+    // It sets no change style to IME selection (the selection is always only
+    // one).  So, the composition string looks like normal (or committed)
+    // string.  At this time, current selection range is same as the
+    // composition string range.  Other applications set a wide caret which
+    // covers the composition string,  however, Gecko doesn't support the wide
+    // caret drawing now (Gecko doesn't support XOR drawing), unfortunately.
+    // For now, we should change the range style to undefined.
+    if (!selectionForTSF->Collapsed() && action->mRanges->Length() == 1) {
+      TextRange& range = action->mRanges->ElementAt(0);
+      LONG start = selectionForTSF->MinOffset();
+      LONG end = selectionForTSF->MaxOffset();
+      if (static_cast<LONG>(range.mStartOffset) ==
+              start - mComposition->StartOffset() &&
+          static_cast<LONG>(range.mEndOffset) ==
+              end - mComposition->StartOffset() &&
+          range.mRangeStyle.IsNoChangeStyle()) {
+        range.mRangeStyle.Clear();
+        // The looks of selected type is better than others.
+        range.mRangeType = TextRangeType::eSelectedRawClause;
+      }
+    }
+
+    // The caret position has to be collapsed.
+    uint32_t caretPosition = static_cast<uint32_t>(
+        selectionForTSF->HasRange()
+            ? selectionForTSF->MaxOffset() - mComposition->StartOffset()
+            : mComposition->StartOffset());
+
+    // If caret is in the target clause and it doesn't have specific style,
+    // the target clause will be painted as normal selection range.  Since
+    // caret shouldn't be in selection range on Windows, we shouldn't append
+    // caret range in such case.
+    const TextRange* targetClause = action->mRanges->GetTargetClause();
+    if (!targetClause || targetClause->mRangeStyle.IsDefined() ||
+        caretPosition < targetClause->mStartOffset ||
+        caretPosition > targetClause->mEndOffset) {
+      TextRange caretRange;
+      caretRange.mStartOffset = caretRange.mEndOffset = caretPosition;
+      caretRange.mRangeType = TextRangeType::eCaret;
+      action->mRanges->AppendElement(caretRange);
+    }
+  }
+
+  action->mIncomplete = false;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::RecordCompositionUpdateAction() "
+           "succeeded",
+           this));
+
+  return S_OK;
+}
+
+HRESULT
+TSFTextStore::SetSelectionInternal(const TS_SELECTION_ACP* pSelection,
+                                   bool aDispatchCompositionChangeEvent) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Debug,
+      ("0x%p   TSFTextStore::SetSelectionInternal(pSelection=%s, "
+       "aDispatchCompositionChangeEvent=%s), mComposition=%s",
+       this, pSelection ? mozilla::ToString(*pSelection).c_str() : "nullptr",
+       GetBoolName(aDispatchCompositionChangeEvent),
+       ToString(mComposition).c_str()));
+
+  MOZ_ASSERT(IsReadWriteLocked());
+
+  Maybe<Selection>& selectionForTSF = SelectionForTSF();
+  if (selectionForTSF.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::SetSelectionInternal() FAILED due to "
+             "SelectionForTSF() failure",
+             this));
+    return E_FAIL;
+  }
+
+  MaybeDispatchKeyboardEventAsProcessedByIME();
+  if (mDestroyed) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::SetSelectionInternal() FAILED due to "
+             "destroyed during dispatching a keyboard event",
+             this));
+    return E_FAIL;
+  }
+
+  // If actually the range is not changing, we should do nothing.
+  // Perhaps, we can ignore the difference change because it must not be
+  // important for following edit.
+  if (selectionForTSF->EqualsExceptDirection(*pSelection)) {
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   TSFTextStore::SetSelectionInternal() Succeeded but "
+             "did nothing because the selection range isn't changing",
+             this));
+    selectionForTSF->SetSelection(*pSelection);
+    return S_OK;
+  }
+
+  if (mComposition.isSome()) {
+    if (aDispatchCompositionChangeEvent) {
+      HRESULT hr = RestartCompositionIfNecessary();
+      if (FAILED(hr)) {
+        MOZ_LOG(gIMELog, LogLevel::Error,
+                ("0x%p   TSFTextStore::SetSelectionInternal() FAILED due to "
+                 "RestartCompositionIfNecessary() failure",
+                 this));
+        return hr;
+      }
+    }
+    if (pSelection->acpStart < mComposition->StartOffset() ||
+        pSelection->acpEnd > mComposition->EndOffset()) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::SetSelectionInternal() FAILED due to "
+               "the selection being out of the composition string",
+               this));
+      return TS_E_INVALIDPOS;
+    }
+    // Emulate selection during compositions
+    selectionForTSF->SetSelection(*pSelection);
+    if (aDispatchCompositionChangeEvent) {
+      HRESULT hr = RecordCompositionUpdateAction();
+      if (FAILED(hr)) {
+        MOZ_LOG(gIMELog, LogLevel::Error,
+                ("0x%p   TSFTextStore::SetSelectionInternal() FAILED due to "
+                 "RecordCompositionUpdateAction() failure",
+                 this));
+        return hr;
+      }
+    }
+    return S_OK;
+  }
+
+  TS_SELECTION_ACP selectionInContent(*pSelection);
+
+  // If mContentForTSF caches old contents which is now different from
+  // actual contents, we need some complicated hack here...
+  // Note that this hack assumes that this is used for reconversion.
+  if (mContentForTSF.isSome() && mPendingTextChangeData.IsValid() &&
+      !mPendingTextChangeData.mCausedOnlyByComposition) {
+    uint32_t startOffset = static_cast<uint32_t>(selectionInContent.acpStart);
+    uint32_t endOffset = static_cast<uint32_t>(selectionInContent.acpEnd);
+    if (mPendingTextChangeData.mStartOffset >= endOffset) {
+      // Setting selection before any changed ranges is fine.
+    } else if (mPendingTextChangeData.mRemovedEndOffset <= startOffset) {
+      // Setting selection after removed range is fine with following
+      // adjustment.
+      selectionInContent.acpStart += mPendingTextChangeData.Difference();
+      selectionInContent.acpEnd += mPendingTextChangeData.Difference();
+    } else if (startOffset == endOffset) {
+      // Moving caret position may be fine in most cases even if the insertion
+      // point has already gone but in this case, composition will be inserted
+      // to unexpected position, though.
+      // It seems that moving caret into middle of the new text is odd.
+      // Perhaps, end of it is expected by users in most cases.
+      selectionInContent.acpStart = mPendingTextChangeData.mAddedEndOffset;
+      selectionInContent.acpEnd = selectionInContent.acpStart;
+    } else {
+      // Otherwise, i.e., setting range has already gone, we cannot set
+      // selection properly.
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::SetSelectionInternal() FAILED due to "
+               "there is unknown content change",
+               this));
+      return E_FAIL;
+    }
+  }
+
+  CompleteLastActionIfStillIncomplete();
+  PendingAction* action = mPendingActions.AppendElement();
+  action->mType = PendingAction::Type::eSetSelection;
+  action->mSelectionStart = selectionInContent.acpStart;
+  action->mSelectionLength =
+      selectionInContent.acpEnd - selectionInContent.acpStart;
+  action->mSelectionReversed = (selectionInContent.style.ase == TS_AE_START);
+
+  // Use TSF specified selection for updating mSelectionForTSF.
+  selectionForTSF->SetSelection(*pSelection);
+
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::SetSelection(ULONG ulCount, const TS_SELECTION_ACP* pSelection) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::SetSelection(ulCount=%lu, pSelection=%s }), "
+           "mComposition=%s",
+           this, ulCount,
+           pSelection ? mozilla::ToString(pSelection).c_str() : "nullptr",
+           ToString(mComposition).c_str()));
+
+  if (!IsReadWriteLocked()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::SetSelection() FAILED due to "
+             "not locked (read-write)",
+             this));
+    return TS_E_NOLOCK;
+  }
+  if (ulCount != 1) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::SetSelection() FAILED due to "
+             "trying setting multiple selection",
+             this));
+    return E_INVALIDARG;
+  }
+  if (!pSelection) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::SetSelection() FAILED due to "
+             "null argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  HRESULT hr = SetSelectionInternal(pSelection, true);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::SetSelection() FAILED due to "
+             "SetSelectionInternal() failure",
+             this));
+  } else {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::SetSelection() succeeded", this));
+  }
+  return hr;
+}
+
+STDMETHODIMP
+TSFTextStore::GetText(LONG acpStart, LONG acpEnd, WCHAR* pchPlain,
+                      ULONG cchPlainReq, ULONG* pcchPlainOut,
+                      TS_RUNINFO* prgRunInfo, ULONG ulRunInfoReq,
+                      ULONG* pulRunInfoOut, LONG* pacpNext) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p TSFTextStore::GetText(acpStart=%ld, acpEnd=%ld, pchPlain=0x%p, "
+       "cchPlainReq=%lu, pcchPlainOut=0x%p, prgRunInfo=0x%p, ulRunInfoReq=%lu, "
+       "pulRunInfoOut=0x%p, pacpNext=0x%p), mComposition=%s",
+       this, acpStart, acpEnd, pchPlain, cchPlainReq, pcchPlainOut, prgRunInfo,
+       ulRunInfoReq, pulRunInfoOut, pacpNext, ToString(mComposition).c_str()));
+
+  if (!IsReadLocked()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetText() FAILED due to "
+             "not locked (read)",
+             this));
+    return TS_E_NOLOCK;
+  }
+
+  if (!pcchPlainOut || (!pchPlain && !prgRunInfo) ||
+      !cchPlainReq != !pchPlain || !ulRunInfoReq != !prgRunInfo) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetText() FAILED due to "
+             "invalid argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  if (acpStart < 0 || acpEnd < -1 || (acpEnd != -1 && acpStart > acpEnd)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetText() FAILED due to "
+             "invalid position",
+             this));
+    return TS_E_INVALIDPOS;
+  }
+
+  // Making sure to null-terminate string just to be on the safe side
+  *pcchPlainOut = 0;
+  if (pchPlain && cchPlainReq) *pchPlain = 0;
+  if (pulRunInfoOut) *pulRunInfoOut = 0;
+  if (pacpNext) *pacpNext = acpStart;
+  if (prgRunInfo && ulRunInfoReq) {
+    prgRunInfo->uCount = 0;
+    prgRunInfo->type = TS_RT_PLAIN;
+  }
+
+  Maybe<Content>& contentForTSF = ContentForTSF();
+  if (contentForTSF.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetText() FAILED due to "
+             "ContentForTSF() failure",
+             this));
+    return E_FAIL;
+  }
+  if (contentForTSF->TextRef().Length() < static_cast<uint32_t>(acpStart)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetText() FAILED due to "
+             "acpStart is larger offset than the actual text length",
+             this));
+    return TS_E_INVALIDPOS;
+  }
+  if (acpEnd != -1 &&
+      contentForTSF->TextRef().Length() < static_cast<uint32_t>(acpEnd)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetText() FAILED due to "
+             "acpEnd is larger offset than the actual text length",
+             this));
+    return TS_E_INVALIDPOS;
+  }
+  uint32_t length = (acpEnd == -1) ? contentForTSF->TextRef().Length() -
+                                         static_cast<uint32_t>(acpStart)
+                                   : static_cast<uint32_t>(acpEnd - acpStart);
+  if (cchPlainReq && cchPlainReq - 1 < length) {
+    length = cchPlainReq - 1;
+  }
+  if (length) {
+    if (pchPlain && cchPlainReq) {
+      const char16_t* startChar =
+          contentForTSF->TextRef().BeginReading() + acpStart;
+      memcpy(pchPlain, startChar, length * sizeof(*pchPlain));
+      pchPlain[length] = 0;
+      *pcchPlainOut = length;
+    }
+    if (prgRunInfo && ulRunInfoReq) {
+      prgRunInfo->uCount = length;
+      prgRunInfo->type = TS_RT_PLAIN;
+      if (pulRunInfoOut) *pulRunInfoOut = 1;
+    }
+    if (pacpNext) *pacpNext = acpStart + length;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::GetText() succeeded: pcchPlainOut=0x%p, "
+           "*prgRunInfo={ uCount=%lu, type=%s }, *pulRunInfoOut=%lu, "
+           "*pacpNext=%ld)",
+           this, pcchPlainOut, prgRunInfo ? prgRunInfo->uCount : 0,
+           prgRunInfo ? GetTextRunTypeName(prgRunInfo->type) : "N/A",
+           pulRunInfoOut ? *pulRunInfoOut : 0, pacpNext ? *pacpNext : 0));
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::SetText(DWORD dwFlags, LONG acpStart, LONG acpEnd,
+                      const WCHAR* pchText, ULONG cch, TS_TEXTCHANGE* pChange) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p TSFTextStore::SetText(dwFlags=%s, acpStart=%ld, acpEnd=%ld, "
+       "pchText=0x%p \"%s\", cch=%lu, pChange=0x%p), mComposition=%s",
+       this, dwFlags == TS_ST_CORRECTION ? "TS_ST_CORRECTION" : "not-specified",
+       acpStart, acpEnd, pchText,
+       pchText && cch ? GetEscapedUTF8String(pchText, cch).get() : "", cch,
+       pChange, ToString(mComposition).c_str()));
+
+  // Per SDK documentation, and since we don't have better
+  // ways to do this, this method acts as a helper to
+  // call SetSelection followed by InsertTextAtSelection
+  if (!IsReadWriteLocked()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::SetText() FAILED due to "
+             "not locked (read)",
+             this));
+    return TS_E_NOLOCK;
+  }
+
+  TS_SELECTION_ACP selection;
+  selection.acpStart = acpStart;
+  selection.acpEnd = acpEnd;
+  selection.style.ase = TS_AE_END;
+  selection.style.fInterimChar = 0;
+  // Set selection to desired range
+  HRESULT hr = SetSelectionInternal(&selection);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::SetText() FAILED due to "
+             "SetSelectionInternal() failure",
+             this));
+    return hr;
+  }
+  // Replace just selected text
+  if (!InsertTextAtSelectionInternal(nsDependentSubstring(pchText, cch),
+                                     pChange)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::SetText() FAILED due to "
+             "InsertTextAtSelectionInternal() failure",
+             this));
+    return E_FAIL;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::SetText() succeeded: pChange={ "
+           "acpStart=%ld, acpOldEnd=%ld, acpNewEnd=%ld }",
+           this, pChange ? pChange->acpStart : 0,
+           pChange ? pChange->acpOldEnd : 0, pChange ? pChange->acpNewEnd : 0));
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::GetFormattedText(LONG acpStart, LONG acpEnd,
+                               IDataObject** ppDataObject) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::GetFormattedText() called "
+           "but not supported (E_NOTIMPL)",
+           this));
+
+  // no support for formatted text
+  return E_NOTIMPL;
+}
+
+STDMETHODIMP
+TSFTextStore::GetEmbedded(LONG acpPos, REFGUID rguidService, REFIID riid,
+                          IUnknown** ppunk) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::GetEmbedded() called "
+           "but not supported (E_NOTIMPL)",
+           this));
+
+  // embedded objects are not supported
+  return E_NOTIMPL;
+}
+
+STDMETHODIMP
+TSFTextStore::QueryInsertEmbedded(const GUID* pguidService,
+                                  const FORMATETC* pFormatEtc,
+                                  BOOL* pfInsertable) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::QueryInsertEmbedded() called "
+           "but not supported, *pfInsertable=FALSE (S_OK)",
+           this));
+
+  // embedded objects are not supported
+  *pfInsertable = FALSE;
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::InsertEmbedded(DWORD dwFlags, LONG acpStart, LONG acpEnd,
+                             IDataObject* pDataObject, TS_TEXTCHANGE* pChange) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::InsertEmbedded() called "
+           "but not supported (E_NOTIMPL)",
+           this));
+
+  // embedded objects are not supported
+  return E_NOTIMPL;
+}
+
+// static
+bool TSFTextStore::ShouldSetInputScopeOfURLBarToDefault() {
+  // FYI: Google Japanese Input may be an IMM-IME.  If it's installed on
+  //      Win7, it's always IMM-IME.  Otherwise, basically, it's a TIP.
+  //      However, if it's installed on Win7 and has not been updated yet
+  //      after the OS is upgraded to Win8 or later, it's still an IMM-IME.
+  //      Therefore, we also need to check with IMMHandler here.
+  if (!StaticPrefs::intl_ime_hack_set_input_scope_of_url_bar_to_default()) {
+    return false;
+  }
+
+  if (IMMHandler::IsGoogleJapaneseInputActive()) {
+    return true;
+  }
+
+  switch (TSFStaticSink::ActiveTIP()) {
+    case TextInputProcessorID::eMicrosoftIMEForJapanese:
+    case TextInputProcessorID::eGoogleJapaneseInput:
+    case TextInputProcessorID::eMicrosoftBopomofo:
+    case TextInputProcessorID::eMicrosoftChangJie:
+    case TextInputProcessorID::eMicrosoftPhonetic:
+    case TextInputProcessorID::eMicrosoftQuick:
+    case TextInputProcessorID::eMicrosoftNewChangJie:
+    case TextInputProcessorID::eMicrosoftNewPhonetic:
+    case TextInputProcessorID::eMicrosoftNewQuick:
+    case TextInputProcessorID::eMicrosoftPinyin:
+    case TextInputProcessorID::eMicrosoftPinyinNewExperienceInputStyle:
+    case TextInputProcessorID::eMicrosoftOldHangul:
+    case TextInputProcessorID::eMicrosoftWubi:
+    case TextInputProcessorID::eMicrosoftIMEForKorean:
+      return true;
+    default:
+      return false;
+  }
+}
+
+void TSFTextStore::SetInputScope(const nsString& aHTMLInputType,
+                                 const nsString& aHTMLInputMode) {
+  mInputScopes.Clear();
+
+  // IME may refer only first input scope, but we will append inputmode's
+  // input scopes too like Chrome since IME may refer it.
+  IMEHandler::AppendInputScopeFromType(aHTMLInputType, mInputScopes);
+  IMEHandler::AppendInputScopeFromInputMode(aHTMLInputMode, mInputScopes);
+
+  if (mInPrivateBrowsing) {
+    mInputScopes.AppendElement(IS_PRIVATE);
+  }
+}
+
+int32_t TSFTextStore::GetRequestedAttrIndex(const TS_ATTRID& aAttrID) {
+  if (IsEqualGUID(aAttrID, GUID_PROP_INPUTSCOPE)) {
+    return eInputScope;
+  }
+  if (IsEqualGUID(aAttrID, sGUID_PROP_URL)) {
+    return eDocumentURL;
+  }
+  if (IsEqualGUID(aAttrID, TSATTRID_Text_VerticalWriting)) {
+    return eTextVerticalWriting;
+  }
+  if (IsEqualGUID(aAttrID, TSATTRID_Text_Orientation)) {
+    return eTextOrientation;
+  }
+  return eNotSupported;
+}
+
+TS_ATTRID
+TSFTextStore::GetAttrID(int32_t aIndex) {
+  switch (aIndex) {
+    case eInputScope:
+      return GUID_PROP_INPUTSCOPE;
+    case eDocumentURL:
+      return sGUID_PROP_URL;
+    case eTextVerticalWriting:
+      return TSATTRID_Text_VerticalWriting;
+    case eTextOrientation:
+      return TSATTRID_Text_Orientation;
+    default:
+      MOZ_CRASH("Invalid index? Or not implemented yet?");
+      return GUID_NULL;
+  }
+}
+
+HRESULT
+TSFTextStore::HandleRequestAttrs(DWORD aFlags, ULONG aFilterCount,
+                                 const TS_ATTRID* aFilterAttrs) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::HandleRequestAttrs(aFlags=%s, "
+           "aFilterCount=%lu)",
+           this, GetFindFlagName(aFlags).get(), aFilterCount));
+
+  // This is a little weird! RequestSupportedAttrs gives us advanced notice
+  // of a support query via RetrieveRequestedAttrs for a specific attribute.
+  // RetrieveRequestedAttrs needs to return valid data for all attributes we
+  // support, but the text service will only want the input scope object
+  // returned in RetrieveRequestedAttrs if the dwFlags passed in here contains
+  // TS_ATTR_FIND_WANT_VALUE.
+  for (int32_t i = 0; i < NUM_OF_SUPPORTED_ATTRS; i++) {
+    mRequestedAttrs[i] = false;
+  }
+  mRequestedAttrValues = !!(aFlags & TS_ATTR_FIND_WANT_VALUE);
+
+  for (uint32_t i = 0; i < aFilterCount; i++) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::HandleRequestAttrs(), "
+             "requested attr=%s",
+             this, GetGUIDNameStrWithTable(aFilterAttrs[i]).get()));
+    int32_t index = GetRequestedAttrIndex(aFilterAttrs[i]);
+    if (index != eNotSupported) {
+      mRequestedAttrs[index] = true;
+    }
+  }
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::RequestSupportedAttrs(DWORD dwFlags, ULONG cFilterAttrs,
+                                    const TS_ATTRID* paFilterAttrs) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::RequestSupportedAttrs(dwFlags=%s, "
+           "cFilterAttrs=%lu)",
+           this, GetFindFlagName(dwFlags).get(), cFilterAttrs));
+
+  return HandleRequestAttrs(dwFlags, cFilterAttrs, paFilterAttrs);
+}
+
+STDMETHODIMP
+TSFTextStore::RequestAttrsAtPosition(LONG acpPos, ULONG cFilterAttrs,
+                                     const TS_ATTRID* paFilterAttrs,
+                                     DWORD dwFlags) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::RequestAttrsAtPosition(acpPos=%ld, "
+           "cFilterAttrs=%lu, dwFlags=%s)",
+           this, acpPos, cFilterAttrs, GetFindFlagName(dwFlags).get()));
+
+  return HandleRequestAttrs(dwFlags | TS_ATTR_FIND_WANT_VALUE, cFilterAttrs,
+                            paFilterAttrs);
+}
+
+STDMETHODIMP
+TSFTextStore::RequestAttrsTransitioningAtPosition(LONG acpPos,
+                                                  ULONG cFilterAttrs,
+                                                  const TS_ATTRID* paFilterAttr,
+                                                  DWORD dwFlags) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::RequestAttrsTransitioningAtPosition("
+           "acpPos=%ld, cFilterAttrs=%lu, dwFlags=%s) called but not supported "
+           "(S_OK)",
+           this, acpPos, cFilterAttrs, GetFindFlagName(dwFlags).get()));
+
+  // no per character attributes defined
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::FindNextAttrTransition(LONG acpStart, LONG acpHalt,
+                                     ULONG cFilterAttrs,
+                                     const TS_ATTRID* paFilterAttrs,
+                                     DWORD dwFlags, LONG* pacpNext,
+                                     BOOL* pfFound, LONG* plFoundOffset) {
+  if (!pacpNext || !pfFound || !plFoundOffset) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  0x%p TSFTextStore::FindNextAttrTransition() FAILED due to "
+             "null argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::FindNextAttrTransition() called "
+           "but not supported (S_OK)",
+           this));
+
+  // no per character attributes defined
+  *pacpNext = *plFoundOffset = acpHalt;
+  *pfFound = FALSE;
+  return S_OK;
+}
+
+// To test the document URL result, define this to out put it to the stdout
+// #define DEBUG_PRINT_DOCUMENT_URL
+
+STDMETHODIMP
+TSFTextStore::RetrieveRequestedAttrs(ULONG ulCount, TS_ATTRVAL* paAttrVals,
+                                     ULONG* pcFetched) {
+  if (!pcFetched || !paAttrVals) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p TSFTextStore::RetrieveRequestedAttrs() FAILED due to "
+             "null argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  ULONG expectedCount = 0;
+  for (int32_t i = 0; i < NUM_OF_SUPPORTED_ATTRS; i++) {
+    if (mRequestedAttrs[i]) {
+      expectedCount++;
+    }
+  }
+  if (ulCount < expectedCount) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p TSFTextStore::RetrieveRequestedAttrs() FAILED due to "
+             "not enough count ulCount=%lu, expectedCount=%lu",
+             this, ulCount, expectedCount));
+    return E_INVALIDARG;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::RetrieveRequestedAttrs() called "
+           "ulCount=%lu, mRequestedAttrValues=%s",
+           this, ulCount, GetBoolName(mRequestedAttrValues)));
+
+  auto GetExposingURL = [&]() -> BSTR {
+    const bool allowed =
+        StaticPrefs::intl_tsf_expose_url_allowed() &&
+        (!mInPrivateBrowsing ||
+         StaticPrefs::intl_tsf_expose_url_in_private_browsing_allowed());
+    if (!allowed || mDocumentURL.IsEmpty()) {
+      BSTR emptyString = ::SysAllocString(L"");
+      MOZ_ASSERT(
+          emptyString,
+          "We need to return valid BSTR pointer to notify TSF of supporting it "
+          "with a pointer to empty string");
+      return emptyString;
+    }
+    return ::SysAllocString(mDocumentURL.get());
+  };
+
+#ifdef DEBUG_PRINT_DOCUMENT_URL
+  {
+    BSTR exposingURL = GetExposingURL();
+    printf("TSFTextStore::RetrieveRequestedAttrs: DocumentURL=\"%s\"\n",
+           NS_ConvertUTF16toUTF8(static_cast<char16ptr_t>(_bstr_t(exposingURL)))
+               .get());
+    ::SysFreeString(exposingURL);
+  }
+#endif  // #ifdef DEBUG_PRINT_DOCUMENT_URL
+
+  int32_t count = 0;
+  for (int32_t i = 0; i < NUM_OF_SUPPORTED_ATTRS; i++) {
+    if (!mRequestedAttrs[i]) {
+      continue;
+    }
+    mRequestedAttrs[i] = false;
+
+    TS_ATTRID attrID = GetAttrID(i);
+
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::RetrieveRequestedAttrs() for %s", this,
+             GetGUIDNameStrWithTable(attrID).get()));
+
+    paAttrVals[count].idAttr = attrID;
+    paAttrVals[count].dwOverlapId = 0;
+
+    if (!mRequestedAttrValues) {
+      paAttrVals[count].varValue.vt = VT_EMPTY;
+    } else {
+      switch (i) {
+        case eInputScope: {
+          paAttrVals[count].varValue.vt = VT_UNKNOWN;
+          RefPtr<IUnknown> inputScope = new InputScopeImpl(mInputScopes);
+          paAttrVals[count].varValue.punkVal = inputScope.forget().take();
+          break;
+        }
+        case eDocumentURL: {
+          paAttrVals[count].varValue.vt = VT_BSTR;
+          paAttrVals[count].varValue.bstrVal = GetExposingURL();
+          break;
+        }
+        case eTextVerticalWriting: {
+          Maybe<Selection>& selectionForTSF = SelectionForTSF();
+          paAttrVals[count].varValue.vt = VT_BOOL;
+          paAttrVals[count].varValue.boolVal =
+              selectionForTSF.isSome() &&
+                      selectionForTSF->WritingModeRef().IsVertical()
+                  ? VARIANT_TRUE
+                  : VARIANT_FALSE;
+          break;
+        }
+        case eTextOrientation: {
+          Maybe<Selection>& selectionForTSF = SelectionForTSF();
+          paAttrVals[count].varValue.vt = VT_I4;
+          paAttrVals[count].varValue.lVal =
+              selectionForTSF.isSome() &&
+                      selectionForTSF->WritingModeRef().IsVertical()
+                  ? 2700
+                  : 0;
+          break;
+        }
+        default:
+          MOZ_CRASH("Invalid index? Or not implemented yet?");
+          break;
+      }
+    }
+    count++;
+  }
+
+  mRequestedAttrValues = false;
+
+  if (count) {
+    *pcFetched = count;
+    return S_OK;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::RetrieveRequestedAttrs() called "
+           "for unknown TS_ATTRVAL, *pcFetched=0 (S_OK)",
+           this));
+
+  paAttrVals->dwOverlapId = 0;
+  paAttrVals->varValue.vt = VT_EMPTY;
+  *pcFetched = 0;
+  return S_OK;
+}
+
+#undef DEBUG_PRINT_DOCUMENT_URL
+
+STDMETHODIMP
+TSFTextStore::GetEndACP(LONG* pacp) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::GetEndACP(pacp=0x%p)", this, pacp));
+
+  if (!IsReadLocked()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetEndACP() FAILED due to "
+             "not locked (read)",
+             this));
+    return TS_E_NOLOCK;
+  }
+
+  if (!pacp) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetEndACP() FAILED due to "
+             "null argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  Maybe<Content>& contentForTSF = ContentForTSF();
+  if (contentForTSF.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetEndACP() FAILED due to "
+             "ContentForTSF() failure",
+             this));
+    return E_FAIL;
+  }
+  *pacp = static_cast<LONG>(contentForTSF->TextRef().Length());
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::GetActiveView(TsViewCookie* pvcView) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::GetActiveView(pvcView=0x%p)", this, pvcView));
+
+  if (!pvcView) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetActiveView() FAILED due to "
+             "null argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  *pvcView = TEXTSTORE_DEFAULT_VIEW;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::GetActiveView() succeeded: *pvcView=%ld", this,
+           *pvcView));
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::GetACPFromPoint(TsViewCookie vcView, const POINT* pt,
+                              DWORD dwFlags, LONG* pacp) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::GetACPFromPoint(pvcView=%ld, pt=%p (x=%ld, "
+           "y=%ld), dwFlags=%s, pacp=%p, mDeferNotifyingTSFUntilNextUpdate=%s, "
+           "mWaitingQueryLayout=%s",
+           this, vcView, pt, pt ? pt->x : 0, pt ? pt->y : 0,
+           GetACPFromPointFlagName(dwFlags).get(), pacp,
+           GetBoolName(mDeferNotifyingTSFUntilNextUpdate),
+           GetBoolName(mWaitingQueryLayout)));
+
+  if (!IsReadLocked()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetACPFromPoint() FAILED due to "
+             "not locked (read)",
+             this));
+    return TS_E_NOLOCK;
+  }
+
+  if (vcView != TEXTSTORE_DEFAULT_VIEW) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetACPFromPoint() FAILED due to "
+             "called with invalid view",
+             this));
+    return E_INVALIDARG;
+  }
+
+  if (!pt) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetACPFromPoint() FAILED due to "
+             "null pt",
+             this));
+    return E_INVALIDARG;
+  }
+
+  if (!pacp) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetACPFromPoint() FAILED due to "
+             "null pacp",
+             this));
+    return E_INVALIDARG;
+  }
+
+  mWaitingQueryLayout = false;
+
+  if (mDestroyed ||
+      (mContentForTSF.isSome() && mContentForTSF->IsLayoutChanged())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetACPFromPoint() returned "
+             "TS_E_NOLAYOUT",
+             this));
+    mHasReturnedNoLayoutError = true;
+    return TS_E_NOLAYOUT;
+  }
+
+  LayoutDeviceIntPoint ourPt(pt->x, pt->y);
+  // Convert to widget relative coordinates from screen's.
+  ourPt -= mWidget->WidgetToScreenOffset();
+
+  // NOTE: Don't check if the point is in the widget since the point can be
+  //       outside of the widget if focused editor is in a XUL <panel>.
+
+  WidgetQueryContentEvent queryCharAtPointEvent(true, eQueryCharacterAtPoint,
+                                                mWidget);
+  mWidget->InitEvent(queryCharAtPointEvent, &ourPt);
+
+  // FYI: WidgetQueryContentEvent may cause flushing pending layout and it
+  //      may cause focus change or something.
+  RefPtr<TSFTextStore> kungFuDeathGrip(this);
+  DispatchEvent(queryCharAtPointEvent);
+  if (!mWidget || mWidget->Destroyed()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetACPFromPoint() FAILED due to "
+             "mWidget was destroyed during eQueryCharacterAtPoint",
+             this));
+    return E_FAIL;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::GetACPFromPoint(), queryCharAtPointEvent={ "
+           "mReply=%s }",
+           this, ToString(queryCharAtPointEvent.mReply).c_str()));
+
+  if (NS_WARN_IF(queryCharAtPointEvent.Failed())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetACPFromPoint() FAILED due to "
+             "eQueryCharacterAtPoint failure",
+             this));
+    return E_FAIL;
+  }
+
+  // If dwFlags isn't set and the point isn't in any character's bounding box,
+  // we should return TS_E_INVALIDPOINT.
+  if (!(dwFlags & GXFPF_NEAREST) && queryCharAtPointEvent.DidNotFindChar()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetACPFromPoint() FAILED due to the "
+             "point contained by no bounding box",
+             this));
+    return TS_E_INVALIDPOINT;
+  }
+
+  // Although, we're not sure if mTentativeCaretOffset becomes NOT_FOUND,
+  // let's assume that there is no content in such case.
+  NS_WARNING_ASSERTION(queryCharAtPointEvent.DidNotFindTentativeCaretOffset(),
+                       "Tentative caret offset was not found");
+
+  uint32_t offset;
+
+  // If dwFlags includes GXFPF_ROUND_NEAREST, we should return tentative
+  // caret offset (MSDN calls it "range position").
+  if (dwFlags & GXFPF_ROUND_NEAREST) {
+    offset = queryCharAtPointEvent.mReply->mTentativeCaretOffset.valueOr(0);
+  } else if (queryCharAtPointEvent.FoundChar()) {
+    // Otherwise, we should return character offset whose bounding box contains
+    // the point.
+    offset = queryCharAtPointEvent.mReply->StartOffset();
+  } else {
+    // If the point isn't in any character's bounding box but we need to return
+    // the nearest character from the point, we should *guess* the character
+    // offset since there is no inexpensive API to check it strictly.
+    // XXX If we retrieve 2 bounding boxes, one is before the offset and
+    //     the other is after the offset, we could resolve the offset.
+    //     However, dispatching 2 eQueryTextRect may be expensive.
+
+    // So, use tentative offset for now.
+    offset = queryCharAtPointEvent.mReply->mTentativeCaretOffset.valueOr(0);
+
+    // However, if it's after the last character, we need to decrement the
+    // offset.
+    Maybe<Content>& contentForTSF = ContentForTSF();
+    if (contentForTSF.isNothing()) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::GetACPFromPoint() FAILED due to "
+               "ContentForTSF() failure",
+               this));
+      return E_FAIL;
+    }
+    if (contentForTSF->TextRef().Length() <= offset) {
+      // If the tentative caret is after the last character, let's return
+      // the last character's offset.
+      offset = contentForTSF->TextRef().Length() - 1;
+    }
+  }
+
+  if (NS_WARN_IF(offset > LONG_MAX)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetACPFromPoint() FAILED due to out of "
+             "range of the result",
+             this));
+    return TS_E_INVALIDPOINT;
+  }
+
+  *pacp = static_cast<LONG>(offset);
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::GetACPFromPoint() succeeded: *pacp=%ld", this,
+           *pacp));
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::GetTextExt(TsViewCookie vcView, LONG acpStart, LONG acpEnd,
+                         RECT* prc, BOOL* pfClipped) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::GetTextExt(vcView=%ld, "
+           "acpStart=%ld, acpEnd=%ld, prc=0x%p, pfClipped=0x%p), "
+           "IsHandlingCompositionInParent()=%s, "
+           "IsHandlingCompositionInContent()=%s, mContentForTSF=%s, "
+           "mSelectionForTSF=%s, mComposition=%s, "
+           "mDeferNotifyingTSFUntilNextUpdate=%s, mWaitingQueryLayout=%s, "
+           "IMEHandler::IsA11yHandlingNativeCaret()=%s",
+           this, vcView, acpStart, acpEnd, prc, pfClipped,
+           GetBoolName(IsHandlingCompositionInParent()),
+           GetBoolName(IsHandlingCompositionInContent()),
+           mozilla::ToString(mContentForTSF).c_str(),
+           ToString(mSelectionForTSF).c_str(), ToString(mComposition).c_str(),
+           GetBoolName(mDeferNotifyingTSFUntilNextUpdate),
+           GetBoolName(mWaitingQueryLayout),
+           GetBoolName(IMEHandler::IsA11yHandlingNativeCaret())));
+
+  if (!IsReadLocked()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetTextExt() FAILED due to "
+             "not locked (read)",
+             this));
+    return TS_E_NOLOCK;
+  }
+
+  if (vcView != TEXTSTORE_DEFAULT_VIEW) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetTextExt() FAILED due to "
+             "called with invalid view",
+             this));
+    return E_INVALIDARG;
+  }
+
+  if (!prc || !pfClipped) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetTextExt() FAILED due to "
+             "null argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  // According to MSDN, ITextStoreACP::GetTextExt() should return
+  // TS_E_INVALIDARG when acpStart and acpEnd are same (i.e., collapsed range).
+  // https://msdn.microsoft.com/en-us/library/windows/desktop/ms538435(v=vs.85).aspx
+  // > TS_E_INVALIDARG: The specified start and end character positions are
+  // >                  equal.
+  // However, some TIPs (including Microsoft's Chinese TIPs!) call this with
+  // collapsed range and if we return TS_E_INVALIDARG, they stops showing their
+  // owning window or shows it but odd position.  So, we should just return
+  // error only when acpStart and/or acpEnd are really odd.
+
+  if (acpStart < 0 || acpEnd < acpStart) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetTextExt() FAILED due to "
+             "invalid position",
+             this));
+    return TS_E_INVALIDPOS;
+  }
+
+  mWaitingQueryLayout = false;
+
+  if (IsHandlingCompositionInContent() && mContentForTSF.isSome() &&
+      mContentForTSF->HasOrHadComposition() &&
+      mContentForTSF->IsLayoutChanged() &&
+      mContentForTSF->MinModifiedOffset().value() >
+          static_cast<uint32_t>(LONG_MAX)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetTextExt(), FAILED due to the text "
+             "is too big for TSF (cannot treat modified offset as LONG), "
+             "mContentForTSF=%s",
+             this, ToString(mContentForTSF).c_str()));
+    return E_FAIL;
+  }
+
+  // At Windows 10 build 17643 (an insider preview for RS5), Microsoft fixed
+  // the bug of TS_E_NOLAYOUT (even when we returned TS_E_NOLAYOUT, TSF
+  // returned E_FAIL to TIP).  However, until we drop to support older Windows
+  // and all TIPs are aware of TS_E_NOLAYOUT result, we need to keep returning
+  // S_OK and available rectangle only for them.
+  if (!MaybeHackNoErrorLayoutBugs(acpStart, acpEnd) &&
+      mContentForTSF.isSome() && mContentForTSF->IsLayoutChangedAt(acpEnd)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetTextExt() returned TS_E_NOLAYOUT "
+             "(acpEnd=%ld)",
+             this, acpEnd));
+    mHasReturnedNoLayoutError = true;
+    return TS_E_NOLAYOUT;
+  }
+
+  if (mDestroyed) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetTextExt() returned TS_E_NOLAYOUT "
+             "(acpEnd=%ld) because this has already been destroyed",
+             this, acpEnd));
+    mHasReturnedNoLayoutError = true;
+    return TS_E_NOLAYOUT;
+  }
+
+  // use eQueryTextRect to get rect in system, screen coordinates
+  WidgetQueryContentEvent queryTextRectEvent(true, eQueryTextRect, mWidget);
+  mWidget->InitEvent(queryTextRectEvent);
+
+  WidgetQueryContentEvent::Options options;
+  int64_t startOffset = acpStart;
+  if (mComposition.isSome()) {
+    // If there is a composition, TSF must want character rects related to
+    // the composition.  Therefore, we should use insertion point relative
+    // query because the composition might be at different position from
+    // the position where TSFTextStore believes it at.
+    options.mRelativeToInsertionPoint = true;
+    startOffset -= mComposition->StartOffset();
+  } else if (IsHandlingCompositionInParent() && mContentForTSF.isSome() &&
+             mContentForTSF->HasOrHadComposition()) {
+    // If there was a composition and its commit event hasn't been dispatched
+    // yet, ContentCacheInParent is still open for relative offset query from
+    // the latest composition.
+    options.mRelativeToInsertionPoint = true;
+    startOffset -= mContentForTSF->LatestCompositionRange()->StartOffset();
+  } else if (!CanAccessActualContentDirectly() &&
+             mSelectionForTSF->HasRange()) {
+    // If TSF/TIP cannot access actual content directly, there may be pending
+    // text and/or selection changes which have not been notified TSF yet.
+    // Therefore, we should use relative to insertion point query since
+    // TSF/TIP computes the offset from the cached selection.
+    options.mRelativeToInsertionPoint = true;
+    startOffset -= mSelectionForTSF->StartOffset();
+  }
+  // ContentEventHandler and ContentCache return actual caret rect when
+  // the queried range is collapsed and selection is collapsed at the
+  // queried range.  Then, its height (in horizontal layout, width in vertical
+  // layout) may be different from actual font height of the line.  In such
+  // case, users see "dancing" of candidate or suggest window of TIP.
+  // For preventing it, we should query text rect with at least 1 length.
+  uint32_t length = std::max(static_cast<int32_t>(acpEnd - acpStart), 1);
+  queryTextRectEvent.InitForQueryTextRect(startOffset, length, options);
+
+  DispatchEvent(queryTextRectEvent);
+  if (NS_WARN_IF(queryTextRectEvent.Failed())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetTextExt() FAILED due to "
+             "eQueryTextRect failure",
+             this));
+    return TS_E_INVALIDPOS;  // but unexpected failure, maybe.
+  }
+
+  // IMEs don't like empty rects, fix here
+  if (queryTextRectEvent.mReply->mRect.Width() <= 0) {
+    queryTextRectEvent.mReply->mRect.SetWidth(1);
+  }
+  if (queryTextRectEvent.mReply->mRect.Height() <= 0) {
+    queryTextRectEvent.mReply->mRect.SetHeight(1);
+  }
+
+  // convert to unclipped screen rect
+  nsWindow* refWindow =
+      static_cast<nsWindow*>(!!queryTextRectEvent.mReply->mFocusedWidget
+                                 ? queryTextRectEvent.mReply->mFocusedWidget
+                                 : static_cast<nsIWidget*>(mWidget.get()));
+  // Result rect is in top level widget coordinates
+  refWindow = refWindow->GetTopLevelWindow(false);
+  if (!refWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetTextExt() FAILED due to "
+             "no top level window",
+             this));
+    return E_FAIL;
+  }
+
+  queryTextRectEvent.mReply->mRect.MoveBy(refWindow->WidgetToScreenOffset());
+
+  // get bounding screen rect to test for clipping
+  if (!GetScreenExtInternal(*prc)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetTextExt() FAILED due to "
+             "GetScreenExtInternal() failure",
+             this));
+    return E_FAIL;
+  }
+
+  // clip text rect to bounding rect
+  RECT textRect;
+  ::SetRect(&textRect, queryTextRectEvent.mReply->mRect.X(),
+            queryTextRectEvent.mReply->mRect.Y(),
+            queryTextRectEvent.mReply->mRect.XMost(),
+            queryTextRectEvent.mReply->mRect.YMost());
+  if (!::IntersectRect(prc, prc, &textRect))
+    // Text is not visible
+    ::SetRectEmpty(prc);
+
+  // not equal if text rect was clipped
+  *pfClipped = !::EqualRect(prc, &textRect);
+
+  // ATOK 2011 - 2016 refers native caret position and size on windows whose
+  // class name is one of Mozilla's windows for deciding candidate window
+  // position.  Additionally, ATOK 2015 and earlier behaves really odd when
+  // we don't create native caret.  Therefore, we need to create native caret
+  // only when ATOK 2011 - 2015 is active (i.e., not necessary for ATOK 2016).
+  // However, if a11y module is handling native caret, we shouldn't touch it.
+  // Note that ATOK must require the latest information of the caret.  So,
+  // even if we'll create native caret later, we need to creat it here with
+  // current information.
+  if (!IMEHandler::IsA11yHandlingNativeCaret() &&
+      StaticPrefs::intl_tsf_hack_atok_create_native_caret() &&
+      TSFStaticSink::IsATOKReferringNativeCaretActive() &&
+      mComposition.isSome() &&
+      mComposition->IsOffsetInRangeOrEndOffset(acpStart) &&
+      mComposition->IsOffsetInRangeOrEndOffset(acpEnd)) {
+    CreateNativeCaret();
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::GetTextExt() succeeded: "
+           "*prc={ left=%ld, top=%ld, right=%ld, bottom=%ld }, *pfClipped=%s",
+           this, prc->left, prc->top, prc->right, prc->bottom,
+           GetBoolName(*pfClipped)));
+
+  return S_OK;
+}
+
+bool TSFTextStore::MaybeHackNoErrorLayoutBugs(LONG& aACPStart, LONG& aACPEnd) {
+  // When ITextStoreACP::GetTextExt() returns TS_E_NOLAYOUT, TSF returns E_FAIL
+  // to its caller (typically, active TIP).  Then, most TIPs abort current job
+  // or treat such application as non-GUI apps.  E.g., some of them give up
+  // showing candidate window, some others show candidate window at top-left of
+  // the screen.  For avoiding this issue, when there is composition (until
+  // composition is actually committed in remote content), we should not
+  // return TS_E_NOLAYOUT error for TIPs whose some features are broken by
+  // this issue.
+  // Note that ideally, this issue should be avoided by each TIP since this
+  // won't be fixed at least on non-latest Windows.  Actually, Google Japanese
+  // Input (based on Mozc) does it.  When GetTextExt() returns E_FAIL, TIPs
+  // should try to check result of GetRangeFromPoint() because TSF returns
+  // TS_E_NOLAYOUT correctly in this case. See:
+  // https://github.com/google/mozc/blob/6b878e31fb6ac4347dc9dfd8ccc1080fe718479f/src/win32/tip/tip_range_util.cc#L237-L257
+
+  if (!IsHandlingCompositionInContent() || mContentForTSF.isNothing() ||
+      !mContentForTSF->HasOrHadComposition() ||
+      !mContentForTSF->IsLayoutChangedAt(aACPEnd)) {
+    return false;
+  }
+
+  MOZ_ASSERT(mComposition.isNothing() ||
+             mComposition->StartOffset() ==
+                 mContentForTSF->LatestCompositionRange()->StartOffset());
+  MOZ_ASSERT(mComposition.isNothing() ||
+             mComposition->EndOffset() ==
+                 mContentForTSF->LatestCompositionRange()->EndOffset());
+
+  // If TSF does not have the bug, we need to hack only with a few TIPs.
+  static const bool sAlllowToStopHackingIfFine =
+      IsWindows10BuildOrLater(17643) &&
+      StaticPrefs::
+          intl_tsf_hack_allow_to_stop_hacking_on_build_17643_or_later();
+
+  // We need to compute active TIP now.  This may take a couple of milliseconds,
+  // however, it'll be cached, so, must be faster than check active TIP every
+  // GetTextExt() calls.
+  const Maybe<Selection>& selectionForTSF = SelectionForTSF();
+  switch (TSFStaticSink::ActiveTIP()) {
+    // MS IME for Japanese doesn't support asynchronous handling at deciding
+    // its suggest list window position.  The feature was implemented
+    // starting from Windows 8.  And also we may meet same trouble in e10s
+    // mode on Win7.  So, we should never return TS_E_NOLAYOUT to MS IME for
+    // Japanese.
+    case TextInputProcessorID::eMicrosoftIMEForJapanese:
+      // Basically, MS-IME tries to retrieve whole composition string rect
+      // at deciding suggest window immediately after unlocking the document.
+      // However, in e10s mode, the content hasn't updated yet in most cases.
+      // Therefore, if the first character at the retrieving range rect is
+      // available, we should use it as the result.
+      // Note that according to bug 1609675, MS-IME for Japanese itself does
+      // not handle TS_E_NOLAYOUT correctly at least on Build 18363.657 (1909).
+      if (StaticPrefs::
+              intl_tsf_hack_ms_japanese_ime_do_not_return_no_layout_error_at_first_char() &&
+          aACPStart < aACPEnd) {
+        aACPEnd = aACPStart;
+        break;
+      }
+      if (sAlllowToStopHackingIfFine) {
+        return false;
+      }
+      // Although, the condition is not clear, MS-IME sometimes retrieves the
+      // caret rect immediately after modifying the composition string but
+      // before unlocking the document.  In such case, we should return the
+      // nearest character rect.
+      // (Let's return true if there is no selection which must be not expected
+      // by MS-IME nor TSF.)
+      if (StaticPrefs::
+              intl_tsf_hack_ms_japanese_ime_do_not_return_no_layout_error_at_caret() &&
+          aACPStart == aACPEnd && selectionForTSF.isSome() &&
+          (!selectionForTSF->HasRange() ||
+           (selectionForTSF->Collapsed() &&
+            selectionForTSF->EndOffset() == aACPEnd))) {
+        int32_t minOffsetOfLayoutChanged =
+            static_cast<int32_t>(mContentForTSF->MinModifiedOffset().value());
+        aACPEnd = aACPStart = std::max(minOffsetOfLayoutChanged - 1, 0);
+      } else {
+        return false;
+      }
+      break;
+    // The bug of Microsoft Office IME 2010 for Japanese is similar to
+    // MS-IME for Win 8.1 and Win 10.  Newer version of MS Office IME is not
+    // released yet.  So, we can hack it without prefs  because there must be
+    // no developers who want to disable this hack for tests.
+    // XXX We have not tested with Microsoft Office IME 2010 since it's
+    //     installable only with Win7 and Win8 (i.e., cannot install Win8.1
+    //     and Win10), and requires upgrade to Win10.
+    case TextInputProcessorID::eMicrosoftOfficeIME2010ForJapanese:
+      // Basically, MS-IME tries to retrieve whole composition string rect
+      // at deciding suggest window immediately after unlocking the document.
+      // However, in e10s mode, the content hasn't updated yet in most cases.
+      // Therefore, if the first character at the retrieving range rect is
+      // available, we should use it as the result.
+      if (aACPStart < aACPEnd) {
+        aACPEnd = aACPStart;
+      }
+      // Although, the condition is not clear, MS-IME sometimes retrieves the
+      // caret rect immediately after modifying the composition string but
+      // before unlocking the document.  In such case, we should return the
+      // nearest character rect.
+      // (Let's return true if there is no selection which must be not expected
+      // by MS-IME nor TSF.)
+      else if (aACPStart == aACPEnd && selectionForTSF.isSome() &&
+               (!selectionForTSF->HasRange() ||
+                (selectionForTSF->Collapsed() &&
+                 selectionForTSF->EndOffset() == aACPEnd))) {
+        int32_t minOffsetOfLayoutChanged =
+            static_cast<int32_t>(mContentForTSF->MinModifiedOffset().value());
+        aACPEnd = aACPStart = std::max(minOffsetOfLayoutChanged - 1, 0);
+      } else {
+        return false;
+      }
+      break;
+    // ATOK fails to handle TS_E_NOLAYOUT only when it decides the position of
+    // suggest window.  In such case, ATOK tries to query rect of whole or a
+    // part of composition string.
+    // FYI: ATOK changes their implementation around candidate window and
+    //      suggest widget at ATOK 2016.  Therefore, there are some differences
+    //      ATOK 2015 (or older) and ATOK 2016 (or newer).
+    // FYI: ATOK 2017 stops referring our window class name.  I.e., ATOK 2016
+    //      and older may behave differently only on Gecko but this must be
+    //      finished from ATOK 2017.
+    // FYI: For testing with legacy ATOK, we should hack it even if current ATOK
+    //      refers native caret rect on windows whose window class is one of
+    //      Mozilla window classes and we stop creating native caret for ATOK
+    //      because creating native caret causes ATOK refers caret position
+    //      when GetTextExt() returns TS_E_NOLAYOUT.
+    case TextInputProcessorID::eATOK2011:
+    case TextInputProcessorID::eATOK2012:
+    case TextInputProcessorID::eATOK2013:
+    case TextInputProcessorID::eATOK2014:
+    case TextInputProcessorID::eATOK2015:
+      // ATOK 2016 and later may temporarily show candidate window at odd
+      // position when you convert a word quickly (e.g., keep pressing
+      // space bar).  So, on ATOK 2016 or later, we need to keep hacking the
+      // result of GetTextExt().
+      if (sAlllowToStopHackingIfFine) {
+        return false;
+      }
+      // If we'll create native caret where we paint our caret.  Then, ATOK
+      // will refer native caret.  So, we don't need to hack anything in
+      // this case.
+      if (StaticPrefs::intl_tsf_hack_atok_create_native_caret()) {
+        MOZ_ASSERT(TSFStaticSink::IsATOKReferringNativeCaretActive());
+        return false;
+      }
+      [[fallthrough]];
+    case TextInputProcessorID::eATOK2016:
+    case TextInputProcessorID::eATOKUnknown:
+      if (!StaticPrefs::
+              intl_tsf_hack_atok_do_not_return_no_layout_error_of_composition_string()) {
+        return false;
+      }
+      // If the range is in the composition string, we should return rectangle
+      // in it as far as possible.
+      if (!mContentForTSF->LatestCompositionRange()->IsOffsetInRangeOrEndOffset(
+              aACPStart) ||
+          !mContentForTSF->LatestCompositionRange()->IsOffsetInRangeOrEndOffset(
+              aACPEnd)) {
+        return false;
+      }
+      break;
+    // Japanist 10 fails to handle TS_E_NOLAYOUT when it decides the position
+    // of candidate window.  In such case, Japanist shows candidate window at
+    // top-left of the screen.  So, we should return the nearest caret rect
+    // where we know.  This is Japanist's bug.  So, even after build 17643,
+    // we need this hack.
+    case TextInputProcessorID::eJapanist10:
+      if (!StaticPrefs::
+              intl_tsf_hack_japanist10_do_not_return_no_layout_error_of_composition_string()) {
+        return false;
+      }
+      if (!mContentForTSF->LatestCompositionRange()->IsOffsetInRangeOrEndOffset(
+              aACPStart) ||
+          !mContentForTSF->LatestCompositionRange()->IsOffsetInRangeOrEndOffset(
+              aACPEnd)) {
+        return false;
+      }
+      break;
+    // Free ChangJie 2010 doesn't handle ITfContextView::GetTextExt() properly.
+    // This must be caused by the bug of TSF since Free ChangJie works fine on
+    // build 17643 and later.
+    case TextInputProcessorID::eFreeChangJie:
+      if (sAlllowToStopHackingIfFine) {
+        return false;
+      }
+      if (!StaticPrefs::
+              intl_tsf_hack_free_chang_jie_do_not_return_no_layout_error()) {
+        return false;
+      }
+      aACPEnd = mContentForTSF->LatestCompositionRange()->StartOffset();
+      aACPStart = std::min(aACPStart, aACPEnd);
+      break;
+    // Some Traditional Chinese TIPs of Microsoft don't show candidate window
+    // in e10s mode on Win8 or later.
+    case TextInputProcessorID::eMicrosoftQuick:
+      if (sAlllowToStopHackingIfFine) {
+        return false;  // MS Quick works fine with Win10 build 17643.
+      }
+      [[fallthrough]];
+    case TextInputProcessorID::eMicrosoftChangJie:
+      if (!StaticPrefs::
+              intl_tsf_hack_ms_traditional_chinese_do_not_return_no_layout_error()) {
+        return false;
+      }
+      aACPEnd = mContentForTSF->LatestCompositionRange()->StartOffset();
+      aACPStart = std::min(aACPStart, aACPEnd);
+      break;
+    // Some Simplified Chinese TIPs of Microsoft don't show candidate window
+    // in e10s mode on Win8 or later.
+    // FYI: Only Simplified Chinese TIPs of Microsoft still require this hack
+    //      because they sometimes do not show candidate window when we return
+    //      TS_E_NOLAYOUT for first query.  Note that even when they show
+    //      candidate window properly, we return TS_E_NOLAYOUT and following
+    //      log looks same as when they don't show candidate window.  Perhaps,
+    //      there is stateful cause or race in them.
+    case TextInputProcessorID::eMicrosoftPinyin:
+    case TextInputProcessorID::eMicrosoftWubi:
+      if (!StaticPrefs::
+              intl_tsf_hack_ms_simplified_chinese_do_not_return_no_layout_error()) {
+        return false;
+      }
+      aACPEnd = mContentForTSF->LatestCompositionRange()->StartOffset();
+      aACPStart = std::min(aACPStart, aACPEnd);
+      break;
+    default:
+      return false;
+  }
+
+  // If we hack the queried range for active TIP, that means we should not
+  // return TS_E_NOLAYOUT even if hacked offset is still modified.  So, as
+  // far as possible, we should adjust the offset.
+  MOZ_ASSERT(mContentForTSF->IsLayoutChanged());
+  bool collapsed = aACPStart == aACPEnd;
+  // Note that even if all characters in the editor or the composition
+  // string was modified, 0 or start offset of the composition string is
+  // useful because it may return caret rect or old character's rect which
+  // the user still see.  That must be useful information for TIP.
+  int32_t firstModifiedOffset =
+      static_cast<int32_t>(mContentForTSF->MinModifiedOffset().value());
+  LONG lastUnmodifiedOffset = std::max(firstModifiedOffset - 1, 0);
+  if (mContentForTSF->IsLayoutChangedAt(aACPStart)) {
+    if (aACPStart >= mContentForTSF->LatestCompositionRange()->StartOffset()) {
+      // If mContentForTSF has last composition string and current
+      // composition string, we can assume that ContentCacheInParent has
+      // cached rects of composition string at least length of current
+      // composition string.  Otherwise, we can assume that rect for
+      // first character of composition string is stored since it was
+      // selection start or caret position.
+      LONG maxCachedOffset =
+          mContentForTSF->LatestCompositionRange()->EndOffset();
+      if (mContentForTSF->LastComposition().isSome()) {
+        maxCachedOffset = std::min(
+            maxCachedOffset, mContentForTSF->LastComposition()->EndOffset());
+      }
+      aACPStart = std::min(aACPStart, maxCachedOffset);
+    }
+    // Otherwise, we don't know which character rects are cached.  So, we
+    // need to use first unmodified character's rect in this case.  Even
+    // if there is no character, the query event will return caret rect
+    // instead.
+    else {
+      aACPStart = lastUnmodifiedOffset;
+    }
+    MOZ_ASSERT(aACPStart <= aACPEnd);
+  }
+
+  // If TIP requests caret rect with collapsed range, we should keep
+  // collapsing the range.
+  if (collapsed) {
+    aACPEnd = aACPStart;
+  }
+  // Let's set aACPEnd to larger offset of last unmodified offset or
+  // aACPStart which may be the first character offset of the composition
+  // string.  However, some TIPs may want to know the right edge of the
+  // range.  Therefore, if aACPEnd is in composition string and active TIP
+  // doesn't retrieve caret rect (i.e., the range isn't collapsed), we
+  // should keep using the original aACPEnd.  Otherwise, we should set
+  // aACPEnd to larger value of aACPStart and lastUnmodifiedOffset.
+  else if (mContentForTSF->IsLayoutChangedAt(aACPEnd) &&
+           !mContentForTSF->LatestCompositionRange()
+                ->IsOffsetInRangeOrEndOffset(aACPEnd)) {
+    aACPEnd = std::max(aACPStart, lastUnmodifiedOffset);
+  }
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Debug,
+      ("0x%p   TSFTextStore::HackNoErrorLayoutBugs() hacked the queried range "
+       "for not returning TS_E_NOLAYOUT, new values are: "
+       "aACPStart=%ld, aACPEnd=%ld",
+       this, aACPStart, aACPEnd));
+
+  return true;
+}
+
+STDMETHODIMP
+TSFTextStore::GetScreenExt(TsViewCookie vcView, RECT* prc) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::GetScreenExt(vcView=%ld, prc=0x%p)", this,
+           vcView, prc));
+
+  if (vcView != TEXTSTORE_DEFAULT_VIEW) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetScreenExt() FAILED due to "
+             "called with invalid view",
+             this));
+    return E_INVALIDARG;
+  }
+
+  if (!prc) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetScreenExt() FAILED due to "
+             "null argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  if (mDestroyed) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetScreenExt() returns empty rect "
+             "due to already destroyed",
+             this));
+    prc->left = prc->top = prc->right = prc->bottom = 0;
+    return S_OK;
+  }
+
+  if (!GetScreenExtInternal(*prc)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetScreenExt() FAILED due to "
+             "GetScreenExtInternal() failure",
+             this));
+    return E_FAIL;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::GetScreenExt() succeeded: "
+           "*prc={ left=%ld, top=%ld, right=%ld, bottom=%ld }",
+           this, prc->left, prc->top, prc->right, prc->bottom));
+  return S_OK;
+}
+
+bool TSFTextStore::GetScreenExtInternal(RECT& aScreenExt) {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::GetScreenExtInternal()", this));
+
+  MOZ_ASSERT(!mDestroyed);
+
+  // use NS_QUERY_EDITOR_RECT to get rect in system, screen coordinates
+  WidgetQueryContentEvent queryEditorRectEvent(true, eQueryEditorRect, mWidget);
+  mWidget->InitEvent(queryEditorRectEvent);
+  DispatchEvent(queryEditorRectEvent);
+  if (queryEditorRectEvent.Failed()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetScreenExtInternal() FAILED due to "
+             "eQueryEditorRect failure",
+             this));
+    return false;
+  }
+
+  nsWindow* refWindow =
+      static_cast<nsWindow*>(!!queryEditorRectEvent.mReply->mFocusedWidget
+                                 ? queryEditorRectEvent.mReply->mFocusedWidget
+                                 : static_cast<nsIWidget*>(mWidget.get()));
+  // Result rect is in top level widget coordinates
+  refWindow = refWindow->GetTopLevelWindow(false);
+  if (!refWindow) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetScreenExtInternal() FAILED due to "
+             "no top level window",
+             this));
+    return false;
+  }
+
+  LayoutDeviceIntRect boundRect = refWindow->GetClientBounds();
+  boundRect.MoveTo(0, 0);
+
+  // Clip frame rect to window rect
+  boundRect.IntersectRect(queryEditorRectEvent.mReply->mRect, boundRect);
+  if (!boundRect.IsEmpty()) {
+    boundRect.MoveBy(refWindow->WidgetToScreenOffset());
+    ::SetRect(&aScreenExt, boundRect.X(), boundRect.Y(), boundRect.XMost(),
+              boundRect.YMost());
+  } else {
+    ::SetRectEmpty(&aScreenExt);
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::GetScreenExtInternal() succeeded: "
+           "aScreenExt={ left=%ld, top=%ld, right=%ld, bottom=%ld }",
+           this, aScreenExt.left, aScreenExt.top, aScreenExt.right,
+           aScreenExt.bottom));
+  return true;
+}
+
+STDMETHODIMP
+TSFTextStore::GetWnd(TsViewCookie vcView, HWND* phwnd) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::GetWnd(vcView=%ld, phwnd=0x%p), "
+           "mWidget=0x%p",
+           this, vcView, phwnd, mWidget.get()));
+
+  if (vcView != TEXTSTORE_DEFAULT_VIEW) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetWnd() FAILED due to "
+             "called with invalid view",
+             this));
+    return E_INVALIDARG;
+  }
+
+  if (!phwnd) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::GetScreenExt() FAILED due to "
+             "null argument",
+             this));
+    return E_INVALIDARG;
+  }
+
+  *phwnd = mWidget ? mWidget->GetWindowHandle() : nullptr;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::GetWnd() succeeded: *phwnd=0x%p", this,
+           static_cast<void*>(*phwnd)));
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::InsertTextAtSelection(DWORD dwFlags, const WCHAR* pchText,
+                                    ULONG cch, LONG* pacpStart, LONG* pacpEnd,
+                                    TS_TEXTCHANGE* pChange) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p TSFTextStore::InsertTextAtSelection(dwFlags=%s, "
+       "pchText=0x%p \"%s\", cch=%lu, pacpStart=0x%p, pacpEnd=0x%p, "
+       "pChange=0x%p), mComposition=%s",
+       this,
+       dwFlags == 0                  ? "0"
+       : dwFlags == TF_IAS_NOQUERY   ? "TF_IAS_NOQUERY"
+       : dwFlags == TF_IAS_QUERYONLY ? "TF_IAS_QUERYONLY"
+                                     : "Unknown",
+       pchText, pchText && cch ? GetEscapedUTF8String(pchText, cch).get() : "",
+       cch, pacpStart, pacpEnd, pChange, ToString(mComposition).c_str()));
+
+  if (cch && !pchText) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::InsertTextAtSelection() FAILED due to "
+             "null pchText",
+             this));
+    return E_INVALIDARG;
+  }
+
+  if (TS_IAS_QUERYONLY == dwFlags) {
+    if (!IsReadLocked()) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::InsertTextAtSelection() FAILED due to "
+               "not locked (read)",
+               this));
+      return TS_E_NOLOCK;
+    }
+
+    if (!pacpStart || !pacpEnd) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::InsertTextAtSelection() FAILED due to "
+               "null argument",
+               this));
+      return E_INVALIDARG;
+    }
+
+    // Get selection first
+    Maybe<Selection>& selectionForTSF = SelectionForTSF();
+    if (selectionForTSF.isNothing()) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::InsertTextAtSelection() FAILED due to "
+               "SelectionForTSF() failure",
+               this));
+      return E_FAIL;
+    }
+
+    // Simulate text insertion
+    if (selectionForTSF->HasRange()) {
+      *pacpStart = selectionForTSF->StartOffset();
+      *pacpEnd = selectionForTSF->EndOffset();
+      if (pChange) {
+        *pChange = TS_TEXTCHANGE{.acpStart = selectionForTSF->StartOffset(),
+                                 .acpOldEnd = selectionForTSF->EndOffset(),
+                                 .acpNewEnd = selectionForTSF->StartOffset() +
+                                              static_cast<LONG>(cch)};
+      }
+    } else {
+      // There is no error code to return "no selection" state from this method.
+      // This means that TSF/TIP should check `GetSelection` result first and
+      // stop using this.  However, this could be called by TIP/TSF if they do
+      // not do so.  Therefore, we should use start of editor instead, but
+      // notify the caller of nothing will be inserted with pChange->acpNewEnd.
+      *pacpStart = *pacpEnd = 0;
+      if (pChange) {
+        *pChange = TS_TEXTCHANGE{.acpStart = 0, .acpOldEnd = 0, .acpNewEnd = 0};
+      }
+    }
+  } else {
+    if (!IsReadWriteLocked()) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::InsertTextAtSelection() FAILED due to "
+               "not locked (read-write)",
+               this));
+      return TS_E_NOLOCK;
+    }
+
+    if (!pChange) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::InsertTextAtSelection() FAILED due to "
+               "null pChange",
+               this));
+      return E_INVALIDARG;
+    }
+
+    if (TS_IAS_NOQUERY != dwFlags && (!pacpStart || !pacpEnd)) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::InsertTextAtSelection() FAILED due to "
+               "null argument",
+               this));
+      return E_INVALIDARG;
+    }
+
+    if (!InsertTextAtSelectionInternal(nsDependentSubstring(pchText, cch),
+                                       pChange)) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::InsertTextAtSelection() FAILED due to "
+               "InsertTextAtSelectionInternal() failure",
+               this));
+      return E_FAIL;
+    }
+
+    if (TS_IAS_NOQUERY != dwFlags) {
+      *pacpStart = pChange->acpStart;
+      *pacpEnd = pChange->acpNewEnd;
+    }
+  }
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::InsertTextAtSelection() succeeded: "
+           "*pacpStart=%ld, *pacpEnd=%ld, "
+           "*pChange={ acpStart=%ld, acpOldEnd=%ld, acpNewEnd=%ld })",
+           this, pacpStart ? *pacpStart : 0, pacpEnd ? *pacpEnd : 0,
+           pChange ? pChange->acpStart : 0, pChange ? pChange->acpOldEnd : 0,
+           pChange ? pChange->acpNewEnd : 0));
+  return S_OK;
+}
+
+bool TSFTextStore::InsertTextAtSelectionInternal(const nsAString& aInsertStr,
+                                                 TS_TEXTCHANGE* aTextChange) {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::InsertTextAtSelectionInternal("
+           "aInsertStr=\"%s\", aTextChange=0x%p), mComposition=%s",
+           this, GetEscapedUTF8String(aInsertStr).get(), aTextChange,
+           ToString(mComposition).c_str()));
+
+  Maybe<Content>& contentForTSF = ContentForTSF();
+  if (contentForTSF.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::InsertTextAtSelectionInternal() failed "
+             "due to ContentForTSF() failure()",
+             this));
+    return false;
+  }
+
+  MaybeDispatchKeyboardEventAsProcessedByIME();
+  if (mDestroyed) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Error,
+        ("0x%p   TSFTextStore::InsertTextAtSelectionInternal() FAILED due to "
+         "destroyed during dispatching a keyboard event",
+         this));
+    return false;
+  }
+
+  const auto numberOfCRLFs = [&]() -> uint32_t {
+    const auto* str = aInsertStr.BeginReading();
+    uint32_t num = 0;
+    for (uint32_t i = 0; i + 1 < aInsertStr.Length(); i++) {
+      if (str[i] == '\r' && str[i + 1] == '\n') {
+        num++;
+        i++;
+      }
+    }
+    return num;
+  }();
+  if (numberOfCRLFs) {
+    nsAutoString key;
+    if (TSFStaticSink::GetActiveTIPNameForTelemetry(key)) {
+      Telemetry::ScalarSet(
+          Telemetry::ScalarID::WIDGET_IME_NAME_ON_WINDOWS_INSERTED_CRLF, key,
+          true);
+    }
+  }
+
+  TS_SELECTION_ACP oldSelection = contentForTSF->Selection()->ACPRef();
+  if (mComposition.isNothing()) {
+    // Use a temporary composition to contain the text
+    PendingAction* compositionStart = mPendingActions.AppendElements(2);
+    PendingAction* compositionEnd = compositionStart + 1;
+
+    compositionStart->mType = PendingAction::Type::eCompositionStart;
+    compositionStart->mSelectionStart = oldSelection.acpStart;
+    compositionStart->mSelectionLength =
+        oldSelection.acpEnd - oldSelection.acpStart;
+    compositionStart->mAdjustSelection = false;
+
+    compositionEnd->mType = PendingAction::Type::eCompositionEnd;
+    compositionEnd->mData = aInsertStr;
+    compositionEnd->mSelectionStart = compositionStart->mSelectionStart;
+
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::InsertTextAtSelectionInternal() "
+             "appending pending compositionstart and compositionend... "
+             "PendingCompositionStart={ mSelectionStart=%ld, "
+             "mSelectionLength=%ld }, PendingCompositionEnd={ mData=\"%s\" "
+             "(Length()=%zu), mSelectionStart=%ld }",
+             this, compositionStart->mSelectionStart,
+             compositionStart->mSelectionLength,
+             GetEscapedUTF8String(compositionEnd->mData).get(),
+             compositionEnd->mData.Length(), compositionEnd->mSelectionStart));
+  }
+
+  contentForTSF->ReplaceSelectedTextWith(aInsertStr);
+
+  if (aTextChange) {
+    aTextChange->acpStart = oldSelection.acpStart;
+    aTextChange->acpOldEnd = oldSelection.acpEnd;
+    aTextChange->acpNewEnd = contentForTSF->Selection()->EndOffset();
+  }
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Debug,
+      ("0x%p   TSFTextStore::InsertTextAtSelectionInternal() "
+       "succeeded: mWidget=0x%p, mWidget->Destroyed()=%s, aTextChange={ "
+       "acpStart=%ld, acpOldEnd=%ld, acpNewEnd=%ld }",
+       this, mWidget.get(), GetBoolName(mWidget ? mWidget->Destroyed() : true),
+       aTextChange ? aTextChange->acpStart : 0,
+       aTextChange ? aTextChange->acpOldEnd : 0,
+       aTextChange ? aTextChange->acpNewEnd : 0));
+  return true;
+}
+
+STDMETHODIMP
+TSFTextStore::InsertEmbeddedAtSelection(DWORD dwFlags, IDataObject* pDataObject,
+                                        LONG* pacpStart, LONG* pacpEnd,
+                                        TS_TEXTCHANGE* pChange) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::InsertEmbeddedAtSelection() called "
+           "but not supported (E_NOTIMPL)",
+           this));
+
+  // embedded objects are not supported
+  return E_NOTIMPL;
+}
+
+HRESULT TSFTextStore::RecordCompositionStartAction(
+    ITfCompositionView* aCompositionView, ITfRange* aRange,
+    bool aPreserveSelection) {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::RecordCompositionStartAction("
+           "aCompositionView=0x%p, aRange=0x%p, aPreserveSelection=%s), "
+           "mComposition=%s",
+           this, aCompositionView, aRange, GetBoolName(aPreserveSelection),
+           ToString(mComposition).c_str()));
+
+  LONG start = 0, length = 0;
+  HRESULT hr = GetRangeExtent(aRange, &start, &length);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RecordCompositionStartAction() FAILED "
+             "due to GetRangeExtent() failure",
+             this));
+    return hr;
+  }
+
+  return RecordCompositionStartAction(aCompositionView, start, length,
+                                      aPreserveSelection);
+}
+
+HRESULT TSFTextStore::RecordCompositionStartAction(
+    ITfCompositionView* aCompositionView, LONG aStart, LONG aLength,
+    bool aPreserveSelection) {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::RecordCompositionStartAction("
+           "aCompositionView=0x%p, aStart=%ld, aLength=%ld, "
+           "aPreserveSelection=%s), "
+           "mComposition=%s",
+           this, aCompositionView, aStart, aLength,
+           GetBoolName(aPreserveSelection), ToString(mComposition).c_str()));
+
+  Maybe<Content>& contentForTSF = ContentForTSF();
+  if (contentForTSF.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RecordCompositionStartAction() FAILED "
+             "due to ContentForTSF() failure",
+             this));
+    return E_FAIL;
+  }
+
+  MaybeDispatchKeyboardEventAsProcessedByIME();
+  if (mDestroyed) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Error,
+        ("0x%p   TSFTextStore::RecordCompositionStartAction() FAILED due to "
+         "destroyed during dispatching a keyboard event",
+         this));
+    return false;
+  }
+
+  CompleteLastActionIfStillIncomplete();
+
+  // TIP may have inserted text at selection before calling
+  // OnStartComposition().  In this case, we've already created a pending
+  // compositionend.  If new composition replaces all commit string of the
+  // pending compositionend, we should cancel the pending compositionend and
+  // keep the previous composition normally.
+  // On Windows 7, MS-IME for Korean, MS-IME 2010 for Korean and MS Old Hangul
+  // may start composition with calling InsertTextAtSelection() and
+  // OnStartComposition() with this order (bug 1208043).
+  // On Windows 10, MS Pinyin, MS Wubi, MS ChangJie and MS Quick commits
+  // last character and replace it with empty string with new composition
+  // when user removes last character of composition string with Backspace
+  // key (bug 1462257).
+  if (!aPreserveSelection &&
+      IsLastPendingActionCompositionEndAt(aStart, aLength)) {
+    const PendingAction& pendingCompositionEnd = mPendingActions.LastElement();
+    contentForTSF->RestoreCommittedComposition(aCompositionView,
+                                               pendingCompositionEnd);
+    mPendingActions.RemoveLastElement();
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::RecordCompositionStartAction() "
+             "succeeded: restoring the committed string as composing string, "
+             "mComposition=%s, mSelectionForTSF=%s",
+             this, ToString(mComposition).c_str(),
+             ToString(mSelectionForTSF).c_str()));
+    return S_OK;
+  }
+
+  PendingAction* action = mPendingActions.AppendElement();
+  action->mType = PendingAction::Type::eCompositionStart;
+  action->mSelectionStart = aStart;
+  action->mSelectionLength = aLength;
+
+  Maybe<Selection>& selectionForTSF = SelectionForTSF();
+  if (selectionForTSF.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RecordCompositionStartAction() FAILED "
+             "due to SelectionForTSF() failure",
+             this));
+    action->mAdjustSelection = true;
+  } else if (!selectionForTSF->HasRange()) {
+    // If there is no selection, let's collapse seletion to the insertion point.
+    action->mAdjustSelection = true;
+  } else if (selectionForTSF->MinOffset() != aStart ||
+             selectionForTSF->MaxOffset() != aStart + aLength) {
+    // If new composition range is different from current selection range,
+    // we need to set selection before dispatching compositionstart event.
+    action->mAdjustSelection = true;
+  } else {
+    // We shouldn't dispatch selection set event before dispatching
+    // compositionstart event because it may cause put caret different
+    // position in HTML editor since generated flat text content and offset in
+    // it are lossy data of HTML contents.
+    action->mAdjustSelection = false;
+  }
+
+  contentForTSF->StartComposition(aCompositionView, *action,
+                                  aPreserveSelection);
+  MOZ_ASSERT(mComposition.isSome());
+  action->mData = mComposition->DataRef();
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::RecordCompositionStartAction() succeeded: "
+           "mComposition=%s, mSelectionForTSF=%s }",
+           this, ToString(mComposition).c_str(),
+           ToString(mSelectionForTSF).c_str()));
+  return S_OK;
+}
+
+HRESULT
+TSFTextStore::RecordCompositionEndAction() {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::RecordCompositionEndAction(), "
+           "mComposition=%s",
+           this, ToString(mComposition).c_str()));
+
+  MOZ_ASSERT(mComposition.isSome());
+
+  if (mComposition.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RecordCompositionEndAction() FAILED due to "
+             "no composition",
+             this));
+    return false;
+  }
+
+  MaybeDispatchKeyboardEventAsProcessedByIME();
+  if (mDestroyed) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RecordCompositionEndAction() FAILED due to "
+             "destroyed during dispatching a keyboard event",
+             this));
+    return false;
+  }
+
+  // If we're handling incomplete composition update or already handled
+  // composition update, we can forget them since composition end will send
+  // the latest composition string and it overwrites the composition string
+  // even if we dispatch eCompositionChange event before that.  So, let's
+  // forget all composition updates now.
+  RemoveLastCompositionUpdateActions();
+  PendingAction* action = mPendingActions.AppendElement();
+  action->mType = PendingAction::Type::eCompositionEnd;
+  action->mData = mComposition->DataRef();
+  action->mSelectionStart = mComposition->StartOffset();
+
+  Maybe<Content>& contentForTSF = ContentForTSF();
+  if (contentForTSF.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::RecordCompositionEndAction() FAILED due "
+             "to ContentForTSF() failure",
+             this));
+    return E_FAIL;
+  }
+  contentForTSF->EndComposition(*action);
+
+  // If this composition was restart but the composition doesn't modify
+  // anything, we should remove the pending composition for preventing to
+  // dispatch redundant composition events.
+  for (size_t i = mPendingActions.Length(), j = 1; i > 0; --i, ++j) {
+    PendingAction& pendingAction = mPendingActions[i - 1];
+    if (pendingAction.mType == PendingAction::Type::eCompositionStart) {
+      if (pendingAction.mData != action->mData) {
+        break;
+      }
+      // When only setting selection is necessary, we should append it.
+      if (pendingAction.mAdjustSelection) {
+        LONG selectionStart = pendingAction.mSelectionStart;
+        LONG selectionLength = pendingAction.mSelectionLength;
+
+        PendingAction* setSelection = mPendingActions.AppendElement();
+        setSelection->mType = PendingAction::Type::eSetSelection;
+        setSelection->mSelectionStart = selectionStart;
+        setSelection->mSelectionLength = selectionLength;
+        setSelection->mSelectionReversed = false;
+      }
+      // Remove the redundant pending composition.
+      mPendingActions.RemoveElementsAt(i - 1, j);
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   TSFTextStore::RecordCompositionEndAction(), "
+               "succeeded, but the composition was canceled due to redundant",
+               this));
+      return S_OK;
+    }
+  }
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p   TSFTextStore::RecordCompositionEndAction(), succeeded", this));
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::OnStartComposition(ITfCompositionView* pComposition, BOOL* pfOk) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::OnStartComposition(pComposition=0x%p, "
+           "pfOk=0x%p), mComposition=%s",
+           this, pComposition, pfOk, ToString(mComposition).c_str()));
+
+  AutoPendingActionAndContentFlusher flusher(this);
+
+  *pfOk = FALSE;
+
+  // Only one composition at a time
+  if (mComposition.isSome()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::OnStartComposition() FAILED due to "
+             "there is another composition already (but returns S_OK)",
+             this));
+    return S_OK;
+  }
+
+  RefPtr<ITfRange> range;
+  HRESULT hr = pComposition->GetRange(getter_AddRefs(range));
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::OnStartComposition() FAILED due to "
+             "pComposition->GetRange() failure",
+             this));
+    return hr;
+  }
+  hr = RecordCompositionStartAction(pComposition, range, false);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::OnStartComposition() FAILED due to "
+             "RecordCompositionStartAction() failure",
+             this));
+    return hr;
+  }
+
+  *pfOk = TRUE;
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::OnStartComposition() succeeded", this));
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::OnUpdateComposition(ITfCompositionView* pComposition,
+                                  ITfRange* pRangeNew) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::OnUpdateComposition(pComposition=0x%p, "
+           "pRangeNew=0x%p), mComposition=%s",
+           this, pComposition, pRangeNew, ToString(mComposition).c_str()));
+
+  AutoPendingActionAndContentFlusher flusher(this);
+
+  if (!mDocumentMgr || !mContext) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::OnUpdateComposition() FAILED due to "
+             "not ready for the composition",
+             this));
+    return E_UNEXPECTED;
+  }
+  if (mComposition.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::OnUpdateComposition() FAILED due to "
+             "no active composition",
+             this));
+    return E_UNEXPECTED;
+  }
+  if (mComposition->GetView() != pComposition) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::OnUpdateComposition() FAILED due to "
+             "different composition view specified",
+             this));
+    return E_UNEXPECTED;
+  }
+
+  // pRangeNew is null when the update is not complete
+  if (!pRangeNew) {
+    MaybeDispatchKeyboardEventAsProcessedByIME();
+    if (mDestroyed) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::OnUpdateComposition() FAILED due to "
+               "destroyed during dispatching a keyboard event",
+               this));
+      return E_FAIL;
+    }
+    PendingAction* action = LastOrNewPendingCompositionUpdate();
+    action->mIncomplete = true;
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::OnUpdateComposition() succeeded but "
+             "not complete",
+             this));
+    return S_OK;
+  }
+
+  HRESULT hr = RestartCompositionIfNecessary(pRangeNew);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::OnUpdateComposition() FAILED due to "
+             "RestartCompositionIfNecessary() failure",
+             this));
+    return hr;
+  }
+
+  hr = RecordCompositionUpdateAction();
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::OnUpdateComposition() FAILED due to "
+             "RecordCompositionUpdateAction() failure",
+             this));
+    return hr;
+  }
+
+  if (MOZ_LOG_TEST(gIMELog, LogLevel::Info)) {
+    Maybe<Selection>& selectionForTSF = SelectionForTSF();
+    if (selectionForTSF.isNothing()) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::OnUpdateComposition() FAILED due to "
+               "SelectionForTSF() failure",
+               this));
+      return S_OK;  // Don't return error only when we're logging.
+    }
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::OnUpdateComposition() succeeded: "
+             "mComposition=%s, SelectionForTSF()=%s",
+             this, ToString(mComposition).c_str(),
+             ToString(selectionForTSF).c_str()));
+  }
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::OnEndComposition(ITfCompositionView* pComposition) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::OnEndComposition(pComposition=0x%p), "
+           "mComposition=%s",
+           this, pComposition, ToString(mComposition).c_str()));
+
+  AutoPendingActionAndContentFlusher flusher(this);
+
+  if (mComposition.isNothing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::OnEndComposition() FAILED due to "
+             "no active composition",
+             this));
+    return E_UNEXPECTED;
+  }
+
+  if (mComposition->GetView() != pComposition) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::OnEndComposition() FAILED due to "
+             "different composition view specified",
+             this));
+    return E_UNEXPECTED;
+  }
+
+  HRESULT hr = RecordCompositionEndAction();
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::OnEndComposition() FAILED due to "
+             "RecordCompositionEndAction() failure",
+             this));
+    return hr;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::OnEndComposition(), succeeded", this));
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::AdviseMouseSink(ITfRangeACP* range, ITfMouseSink* pSink,
+                              DWORD* pdwCookie) {
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p TSFTextStore::AdviseMouseSink(range=0x%p, pSink=0x%p, "
+           "pdwCookie=0x%p)",
+           this, range, pSink, pdwCookie));
+
+  if (!pdwCookie) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::AdviseMouseSink() FAILED due to the "
+             "pdwCookie is null",
+             this));
+    return E_INVALIDARG;
+  }
+  // Initialize the result with invalid cookie for safety.
+  *pdwCookie = MouseTracker::kInvalidCookie;
+
+  if (!range) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::AdviseMouseSink() FAILED due to the "
+             "range is null",
+             this));
+    return E_INVALIDARG;
+  }
+  if (!pSink) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::AdviseMouseSink() FAILED due to the "
+             "pSink is null",
+             this));
+    return E_INVALIDARG;
+  }
+
+  // Looking for an unusing tracker.
+  MouseTracker* tracker = nullptr;
+  for (size_t i = 0; i < mMouseTrackers.Length(); i++) {
+    if (mMouseTrackers[i].IsUsing()) {
+      continue;
+    }
+    tracker = &mMouseTrackers[i];
+  }
+  // If there is no unusing tracker, create new one.
+  // XXX Should we make limitation of the number of installs?
+  if (!tracker) {
+    tracker = mMouseTrackers.AppendElement();
+    HRESULT hr = tracker->Init(this);
+    if (FAILED(hr)) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("0x%p   TSFTextStore::AdviseMouseSink() FAILED due to "
+               "failure of MouseTracker::Init()",
+               this));
+      return hr;
+    }
+  }
+  HRESULT hr = tracker->AdviseSink(this, range, pSink);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::AdviseMouseSink() FAILED due to failure "
+             "of MouseTracker::Init()",
+             this));
+    return hr;
+  }
+  *pdwCookie = tracker->Cookie();
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::AdviseMouseSink(), succeeded, "
+           "*pdwCookie=%ld",
+           this, *pdwCookie));
+  return S_OK;
+}
+
+STDMETHODIMP
+TSFTextStore::UnadviseMouseSink(DWORD dwCookie) {
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p TSFTextStore::UnadviseMouseSink(dwCookie=%ld)", this, dwCookie));
+  if (dwCookie == MouseTracker::kInvalidCookie) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::UnadviseMouseSink() FAILED due to "
+             "the cookie is invalid value",
+             this));
+    return E_INVALIDARG;
+  }
+  // The cookie value must be an index of mMouseTrackers.
+  // We can use this shortcut for now.
+  if (static_cast<size_t>(dwCookie) >= mMouseTrackers.Length()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::UnadviseMouseSink() FAILED due to "
+             "the cookie is too large value",
+             this));
+    return E_INVALIDARG;
+  }
+  MouseTracker& tracker = mMouseTrackers[dwCookie];
+  if (!tracker.IsUsing()) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::UnadviseMouseSink() FAILED due to "
+             "the found tracker uninstalled already",
+             this));
+    return E_INVALIDARG;
+  }
+  tracker.UnadviseSink();
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::UnadviseMouseSink(), succeeded", this));
+  return S_OK;
+}
+
+// static
+nsresult TSFTextStore::OnFocusChange(bool aGotFocus, nsWindow* aFocusedWidget,
+                                     const InputContext& aContext) {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("  TSFTextStore::OnFocusChange(aGotFocus=%s, "
+           "aFocusedWidget=0x%p, aContext=%s), "
+           "sThreadMgr=0x%p, sEnabledTextStore=0x%p",
+           GetBoolName(aGotFocus), aFocusedWidget,
+           mozilla::ToString(aContext).c_str(), sThreadMgr.get(),
+           sEnabledTextStore.get()));
+
+  if (NS_WARN_IF(!IsInTSFMode())) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  RefPtr<ITfDocumentMgr> prevFocusedDocumentMgr;
+  bool hasFocus = ThinksHavingFocus();
+  RefPtr<TSFTextStore> oldTextStore = sEnabledTextStore.forget();
+
+  // If currently oldTextStore still has focus, notifies TSF of losing focus.
+  if (hasFocus) {
+    RefPtr<ITfThreadMgr> threadMgr = sThreadMgr;
+    DebugOnly<HRESULT> hr = threadMgr->AssociateFocus(
+        oldTextStore->mWidget->GetWindowHandle(), nullptr,
+        getter_AddRefs(prevFocusedDocumentMgr));
+    NS_ASSERTION(SUCCEEDED(hr), "Disassociating focus failed");
+    NS_ASSERTION(prevFocusedDocumentMgr == oldTextStore->mDocumentMgr,
+                 "different documentMgr has been associated with the window");
+  }
+
+  // Even if there was a focused TextStore, we won't use it with new focused
+  // editor.  So, release it now.
+  if (oldTextStore) {
+    oldTextStore->Destroy();
+  }
+
+  if (NS_WARN_IF(!sThreadMgr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::OnFocusChange() FAILED, due to "
+             "sThreadMgr being destroyed during calling "
+             "ITfThreadMgr::AssociateFocus()"));
+    return NS_ERROR_FAILURE;
+  }
+  if (NS_WARN_IF(sEnabledTextStore)) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Error,
+        ("  TSFTextStore::OnFocusChange() FAILED, due to "
+         "nested event handling has created another focused TextStore during "
+         "calling ITfThreadMgr::AssociateFocus()"));
+    return NS_ERROR_FAILURE;
+  }
+
+  // If this is a notification of blur, move focus to the dummy document
+  // manager.
+  if (!aGotFocus || !aContext.mIMEState.IsEditable()) {
+    RefPtr<ITfThreadMgr> threadMgr = sThreadMgr;
+    RefPtr<ITfDocumentMgr> disabledDocumentMgr = sDisabledDocumentMgr;
+    HRESULT hr = threadMgr->SetFocus(disabledDocumentMgr);
+    if (NS_WARN_IF(FAILED(hr))) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("  TSFTextStore::OnFocusChange() FAILED due to "
+               "ITfThreadMgr::SetFocus() failure"));
+      return NS_ERROR_FAILURE;
+    }
+    return NS_OK;
+  }
+
+  // If an editor is getting focus, create new TextStore and set focus.
+  if (NS_WARN_IF(!CreateAndSetFocus(aFocusedWidget, aContext))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::OnFocusChange() FAILED due to "
+             "ITfThreadMgr::CreateAndSetFocus() failure"));
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+// static
+void TSFTextStore::EnsureToDestroyAndReleaseEnabledTextStoreIf(
+    RefPtr<TSFTextStore>& aTextStore) {
+  aTextStore->Destroy();
+  if (sEnabledTextStore == aTextStore) {
+    sEnabledTextStore = nullptr;
+  }
+  aTextStore = nullptr;
+}
+
+// static
+bool TSFTextStore::CreateAndSetFocus(nsWindow* aFocusedWidget,
+                                     const InputContext& aContext) {
+  // TSF might do something which causes that we need to access static methods
+  // of TSFTextStore.  At that time, sEnabledTextStore may be necessary.
+  // So, we should set sEnabledTextStore directly.
+  RefPtr<TSFTextStore> textStore = new TSFTextStore();
+  sEnabledTextStore = textStore;
+  if (NS_WARN_IF(!textStore->Init(aFocusedWidget, aContext))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::CreateAndSetFocus() FAILED due to "
+             "TSFTextStore::Init() failure"));
+    EnsureToDestroyAndReleaseEnabledTextStoreIf(textStore);
+    return false;
+  }
+  RefPtr<ITfDocumentMgr> newDocMgr = textStore->mDocumentMgr;
+  if (NS_WARN_IF(!newDocMgr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::CreateAndSetFocus() FAILED due to "
+             "invalid TSFTextStore::mDocumentMgr"));
+    EnsureToDestroyAndReleaseEnabledTextStoreIf(textStore);
+    return false;
+  }
+  if (aContext.mIMEState.mEnabled == IMEEnabled::Password) {
+    MarkContextAsKeyboardDisabled(textStore->mContext);
+    RefPtr<ITfContext> topContext;
+    newDocMgr->GetTop(getter_AddRefs(topContext));
+    if (topContext && topContext != textStore->mContext) {
+      MarkContextAsKeyboardDisabled(topContext);
+    }
+  }
+
+  HRESULT hr;
+  RefPtr<ITfThreadMgr> threadMgr = sThreadMgr;
+  hr = threadMgr->SetFocus(newDocMgr);
+
+  if (NS_WARN_IF(FAILED(hr))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::CreateAndSetFocus() FAILED due to "
+             "ITfTheadMgr::SetFocus() failure"));
+    EnsureToDestroyAndReleaseEnabledTextStoreIf(textStore);
+    return false;
+  }
+  if (NS_WARN_IF(!sThreadMgr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::CreateAndSetFocus() FAILED due to "
+             "sThreadMgr being destroyed during calling "
+             "ITfTheadMgr::SetFocus()"));
+    EnsureToDestroyAndReleaseEnabledTextStoreIf(textStore);
+    return false;
+  }
+  if (NS_WARN_IF(sEnabledTextStore != textStore)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::CreateAndSetFocus() FAILED due to "
+             "creating TextStore has lost focus during calling "
+             "ITfThreadMgr::SetFocus()"));
+    EnsureToDestroyAndReleaseEnabledTextStoreIf(textStore);
+    return false;
+  }
+
+  // Use AssociateFocus() for ensuring that any native focus event
+  // never steal focus from our documentMgr.
+  RefPtr<ITfDocumentMgr> prevFocusedDocumentMgr;
+  hr = threadMgr->AssociateFocus(aFocusedWidget->GetWindowHandle(), newDocMgr,
+                                 getter_AddRefs(prevFocusedDocumentMgr));
+  if (NS_WARN_IF(FAILED(hr))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::CreateAndSetFocus() FAILED due to "
+             "ITfTheadMgr::AssociateFocus() failure"));
+    EnsureToDestroyAndReleaseEnabledTextStoreIf(textStore);
+    return false;
+  }
+  if (NS_WARN_IF(!sThreadMgr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::CreateAndSetFocus() FAILED due to "
+             "sThreadMgr being destroyed during calling "
+             "ITfTheadMgr::AssociateFocus()"));
+    EnsureToDestroyAndReleaseEnabledTextStoreIf(textStore);
+    return false;
+  }
+  if (NS_WARN_IF(sEnabledTextStore != textStore)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::CreateAndSetFocus() FAILED due to "
+             "creating TextStore has lost focus during calling "
+             "ITfTheadMgr::AssociateFocus()"));
+    EnsureToDestroyAndReleaseEnabledTextStoreIf(textStore);
+    return false;
+  }
+
+  if (textStore->mSink) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("  TSFTextStore::CreateAndSetFocus(), calling "
+             "ITextStoreACPSink::OnLayoutChange(TS_LC_CREATE) for 0x%p...",
+             textStore.get()));
+    RefPtr<ITextStoreACPSink> sink = textStore->mSink;
+    sink->OnLayoutChange(TS_LC_CREATE, TEXTSTORE_DEFAULT_VIEW);
+    if (NS_WARN_IF(sEnabledTextStore != textStore)) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("  TSFTextStore::CreateAndSetFocus() FAILED due to "
+               "creating TextStore has lost focus during calling "
+               "ITextStoreACPSink::OnLayoutChange(TS_LC_CREATE)"));
+      EnsureToDestroyAndReleaseEnabledTextStoreIf(textStore);
+      return false;
+    }
+  }
+  return true;
+}
+
+// static
+IMENotificationRequests TSFTextStore::GetIMENotificationRequests() {
+  if (!sEnabledTextStore || NS_WARN_IF(!sEnabledTextStore->mDocumentMgr)) {
+    // If there is no active text store, we don't need any notifications
+    // since there is no sink which needs notifications.
+    return IMENotificationRequests();
+  }
+
+  // Otherwise, requests all notifications since even if some of them may not
+  // be required by the sink of active TIP, active TIP may be changed and
+  // other TIPs may need all notifications.
+  // Note that Windows temporarily steal focus from active window if the main
+  // process which created the window becomes busy.  In this case, we shouldn't
+  // commit composition since user may want to continue to compose the
+  // composition after becoming not busy.  Therefore, we need notifications
+  // even during deactive.
+  // Be aware, we don't need to check actual focused text store.  For example,
+  // MS-IME for Japanese handles focus messages by themselves and sets focused
+  // text store to nullptr when the process is being inactivated.  However,
+  // we still need to reuse sEnabledTextStore if the process is activated and
+  // focused element isn't changed.  Therefore, if sEnabledTextStore isn't
+  // nullptr, we need to keep notifying the sink even when it is not focused
+  // text store for the thread manager.
+  return IMENotificationRequests(
+      IMENotificationRequests::NOTIFY_TEXT_CHANGE |
+      IMENotificationRequests::NOTIFY_POSITION_CHANGE |
+      IMENotificationRequests::NOTIFY_MOUSE_BUTTON_EVENT_ON_CHAR |
+      IMENotificationRequests::NOTIFY_DURING_DEACTIVE);
+}
+
+nsresult TSFTextStore::OnTextChangeInternal(
+    const IMENotification& aIMENotification) {
+  const TextChangeDataBase& textChangeData = aIMENotification.mTextChangeData;
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::OnTextChangeInternal(aIMENotification={ "
+           "mMessage=0x%08X, mTextChangeData=%s }), "
+           "mDestroyed=%s, mSink=0x%p, mSinkMask=%s, "
+           "mComposition=%s",
+           this, aIMENotification.mMessage,
+           mozilla::ToString(textChangeData).c_str(), GetBoolName(mDestroyed),
+           mSink.get(), GetSinkMaskNameStr(mSinkMask).get(),
+           ToString(mComposition).c_str()));
+
+  if (mDestroyed) {
+    // If this instance is already destroyed, we shouldn't notify TSF of any
+    // changes.
+    return NS_OK;
+  }
+
+  mDeferNotifyingTSFUntilNextUpdate = false;
+
+  // Different from selection change, we don't modify anything with text
+  // change data.  Therefore, if neither TSF not TIP wants text change
+  // notifications, we don't need to store the changes.
+  if (!mSink || !(mSinkMask & TS_AS_TEXT_CHANGE)) {
+    return NS_OK;
+  }
+
+  // Merge any text change data even if it's caused by composition.
+  mPendingTextChangeData.MergeWith(textChangeData);
+
+  MaybeFlushPendingNotifications();
+
+  return NS_OK;
+}
+
+void TSFTextStore::NotifyTSFOfTextChange() {
+  MOZ_ASSERT(!mDestroyed);
+  MOZ_ASSERT(!IsReadLocked());
+  MOZ_ASSERT(mComposition.isNothing());
+  MOZ_ASSERT(mPendingTextChangeData.IsValid());
+
+  // If the text changes are caused only by composition, we don't need to
+  // notify TSF of the text changes.
+  if (mPendingTextChangeData.mCausedOnlyByComposition) {
+    mPendingTextChangeData.Clear();
+    return;
+  }
+
+  // First, forget cached selection.
+  mSelectionForTSF.reset();
+
+  // For making it safer, we should check if there is a valid sink to receive
+  // text change notification.
+  if (NS_WARN_IF(!mSink) || NS_WARN_IF(!(mSinkMask & TS_AS_TEXT_CHANGE))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::NotifyTSFOfTextChange() FAILED due to "
+             "mSink is not ready to call ITextStoreACPSink::OnTextChange()...",
+             this));
+    mPendingTextChangeData.Clear();
+    return;
+  }
+
+  if (NS_WARN_IF(!mPendingTextChangeData.IsInInt32Range())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::NotifyTSFOfTextChange() FAILED due to "
+             "offset is too big for calling "
+             "ITextStoreACPSink::OnTextChange()...",
+             this));
+    mPendingTextChangeData.Clear();
+    return;
+  }
+
+  TS_TEXTCHANGE textChange;
+  textChange.acpStart = static_cast<LONG>(mPendingTextChangeData.mStartOffset);
+  textChange.acpOldEnd =
+      static_cast<LONG>(mPendingTextChangeData.mRemovedEndOffset);
+  textChange.acpNewEnd =
+      static_cast<LONG>(mPendingTextChangeData.mAddedEndOffset);
+  mPendingTextChangeData.Clear();
+
+  MOZ_LOG(
+      gIMELog, LogLevel::Info,
+      ("0x%p   TSFTextStore::NotifyTSFOfTextChange(), calling "
+       "ITextStoreACPSink::OnTextChange(0, { acpStart=%ld, acpOldEnd=%ld, "
+       "acpNewEnd=%ld })...",
+       this, textChange.acpStart, textChange.acpOldEnd, textChange.acpNewEnd));
+  RefPtr<ITextStoreACPSink> sink = mSink;
+  sink->OnTextChange(0, &textChange);
+}
+
+nsresult TSFTextStore::OnSelectionChangeInternal(
+    const IMENotification& aIMENotification) {
+  const SelectionChangeDataBase& selectionChangeData =
+      aIMENotification.mSelectionChangeData;
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::OnSelectionChangeInternal("
+           "aIMENotification={ mSelectionChangeData=%s }), mDestroyed=%s, "
+           "mSink=0x%p, mSinkMask=%s, mIsRecordingActionsWithoutLock=%s, "
+           "mComposition=%s",
+           this, mozilla::ToString(selectionChangeData).c_str(),
+           GetBoolName(mDestroyed), mSink.get(),
+           GetSinkMaskNameStr(mSinkMask).get(),
+           GetBoolName(mIsRecordingActionsWithoutLock),
+           ToString(mComposition).c_str()));
+
+  if (mDestroyed) {
+    // If this instance is already destroyed, we shouldn't notify TSF of any
+    // changes.
+    return NS_OK;
+  }
+
+  mDeferNotifyingTSFUntilNextUpdate = false;
+
+  // Assign the new selection change data to the pending selection change data
+  // because only the latest selection data is necessary.
+  // Note that this is necessary to update mSelectionForTSF.  Therefore, even if
+  // neither TSF nor TIP wants selection change notifications, we need to
+  // store the selection information.
+  mPendingSelectionChangeData = Some(selectionChangeData);
+
+  // Flush remaining pending notifications here if it's possible.
+  MaybeFlushPendingNotifications();
+
+  // If we're available, we should create native caret instead of IMEHandler
+  // because we may have some cache to do it.
+  // Note that if we have composition, we'll notified composition-updated
+  // later so that we don't need to create native caret in such case.
+  if (!IsHandlingCompositionInContent() &&
+      IMEHandler::NeedsToCreateNativeCaret()) {
+    CreateNativeCaret();
+  }
+
+  return NS_OK;
+}
+
+void TSFTextStore::NotifyTSFOfSelectionChange() {
+  MOZ_ASSERT(!mDestroyed);
+  MOZ_ASSERT(!IsReadLocked());
+  MOZ_ASSERT(mComposition.isNothing());
+  MOZ_ASSERT(mPendingSelectionChangeData.isSome());
+
+  // If selection range isn't actually changed, we don't need to notify TSF
+  // of this selection change.
+  if (mSelectionForTSF.isNothing()) {
+    MOZ_DIAGNOSTIC_ASSERT(!mIsInitializingSelectionForTSF,
+                          "While mSelectionForTSF is being initialized, this "
+                          "should not be called");
+    mSelectionForTSF.emplace(*mPendingSelectionChangeData);
+  } else if (!mSelectionForTSF->SetSelection(*mPendingSelectionChangeData)) {
+    mPendingSelectionChangeData.reset();
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::NotifyTSFOfSelectionChange(), "
+             "selection isn't actually changed.",
+             this));
+    return;
+  }
+
+  mPendingSelectionChangeData.reset();
+
+  if (!mSink || !(mSinkMask & TS_AS_SEL_CHANGE)) {
+    return;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::NotifyTSFOfSelectionChange(), calling "
+           "ITextStoreACPSink::OnSelectionChange()...",
+           this));
+  RefPtr<ITextStoreACPSink> sink = mSink;
+  sink->OnSelectionChange();
+}
+
+nsresult TSFTextStore::OnLayoutChangeInternal() {
+  if (mDestroyed) {
+    // If this instance is already destroyed, we shouldn't notify TSF of any
+    // changes.
+    return NS_OK;
+  }
+
+  NS_ENSURE_TRUE(mContext, NS_ERROR_FAILURE);
+  NS_ENSURE_TRUE(mSink, NS_ERROR_FAILURE);
+
+  mDeferNotifyingTSFUntilNextUpdate = false;
+
+  nsresult rv = NS_OK;
+
+  // We need to notify TSF of layout change even if the document is locked.
+  // So, don't use MaybeFlushPendingNotifications() for flushing pending
+  // layout change.
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::OnLayoutChangeInternal(), calling "
+           "NotifyTSFOfLayoutChange()...",
+           this));
+  if (NS_WARN_IF(!NotifyTSFOfLayoutChange())) {
+    rv = NS_ERROR_FAILURE;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::OnLayoutChangeInternal(), calling "
+           "MaybeFlushPendingNotifications()...",
+           this));
+  MaybeFlushPendingNotifications();
+
+  return rv;
+}
+
+bool TSFTextStore::NotifyTSFOfLayoutChange() {
+  MOZ_ASSERT(!mDestroyed);
+
+  // If we're waiting a query of layout information from TIP, it means that
+  // we've returned TS_E_NOLAYOUT error.
+  bool returnedNoLayoutError = mHasReturnedNoLayoutError || mWaitingQueryLayout;
+
+  // If we returned TS_E_NOLAYOUT, TIP should query the computed layout again.
+  mWaitingQueryLayout = returnedNoLayoutError;
+
+  // For avoiding to call this method again at unlocking the document during
+  // calls of OnLayoutChange(), reset mHasReturnedNoLayoutError.
+  mHasReturnedNoLayoutError = false;
+
+  // Now, layout has been computed.  We should notify mContentForTSF for
+  // making GetTextExt() and GetACPFromPoint() not return TS_E_NOLAYOUT.
+  if (mContentForTSF.isSome()) {
+    mContentForTSF->OnLayoutChanged();
+  }
+
+  if (IMEHandler::NeedsToCreateNativeCaret()) {
+    // If we're available, we should create native caret instead of IMEHandler
+    // because we may have some cache to do it.
+    CreateNativeCaret();
+  } else {
+    // Now, the caret position is different from ours.  Destroy the native caret
+    // if we've create it only for GetTextExt().
+    IMEHandler::MaybeDestroyNativeCaret();
+  }
+
+  // This method should return true if either way succeeds.
+  bool ret = true;
+
+  if (mSink) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::NotifyTSFOfLayoutChange(), "
+             "calling ITextStoreACPSink::OnLayoutChange()...",
+             this));
+    RefPtr<ITextStoreACPSink> sink = mSink;
+    HRESULT hr = sink->OnLayoutChange(TS_LC_CHANGE, TEXTSTORE_DEFAULT_VIEW);
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::NotifyTSFOfLayoutChange(), "
+             "called ITextStoreACPSink::OnLayoutChange()",
+             this));
+    ret = SUCCEEDED(hr);
+  }
+
+  // The layout change caused by composition string change should cause
+  // calling ITfContextOwnerServices::OnLayoutChange() too.
+  if (returnedNoLayoutError && mContext) {
+    RefPtr<ITfContextOwnerServices> service;
+    mContext->QueryInterface(IID_ITfContextOwnerServices,
+                             getter_AddRefs(service));
+    if (service) {
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   TSFTextStore::NotifyTSFOfLayoutChange(), "
+               "calling ITfContextOwnerServices::OnLayoutChange()...",
+               this));
+      HRESULT hr = service->OnLayoutChange();
+      ret = ret && SUCCEEDED(hr);
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   TSFTextStore::NotifyTSFOfLayoutChange(), "
+               "called ITfContextOwnerServices::OnLayoutChange()",
+               this));
+    }
+  }
+
+  if (!mWidget || mWidget->Destroyed()) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::NotifyTSFOfLayoutChange(), "
+             "the widget is destroyed during calling OnLayoutChange()",
+             this));
+    return ret;
+  }
+
+  if (mDestroyed) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::NotifyTSFOfLayoutChange(), "
+             "the TSFTextStore instance is destroyed during calling "
+             "OnLayoutChange()",
+             this));
+    return ret;
+  }
+
+  // If we returned TS_E_NOLAYOUT again, we need another call of
+  // OnLayoutChange() later.  So, let's wait a query from TIP.
+  if (mHasReturnedNoLayoutError) {
+    mWaitingQueryLayout = true;
+  }
+
+  if (!mWaitingQueryLayout) {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::NotifyTSFOfLayoutChange(), "
+             "succeeded notifying TIP of our layout change",
+             this));
+    return ret;
+  }
+
+  // If we believe that TIP needs to retry to retrieve our layout information
+  // later, we should call it with ::PostMessage() hack.
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::NotifyTSFOfLayoutChange(), "
+           "posing  MOZ_WM_NOTIY_TSF_OF_LAYOUT_CHANGE for calling "
+           "OnLayoutChange() again...",
+           this));
+  ::PostMessage(mWidget->GetWindowHandle(), MOZ_WM_NOTIY_TSF_OF_LAYOUT_CHANGE,
+                reinterpret_cast<WPARAM>(this), 0);
+
+  return true;
+}
+
+void TSFTextStore::NotifyTSFOfLayoutChangeAgain() {
+  // Don't notify TSF of layout change after destroyed.
+  if (mDestroyed) {
+    mWaitingQueryLayout = false;
+    return;
+  }
+
+  // Before preforming this method, TIP has accessed our layout information by
+  // itself.  In such case, we don't need to call OnLayoutChange() anymore.
+  if (!mWaitingQueryLayout) {
+    return;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("0x%p   TSFTextStore::NotifyTSFOfLayoutChangeAgain(), "
+           "calling NotifyTSFOfLayoutChange()...",
+           this));
+  NotifyTSFOfLayoutChange();
+
+  // If TIP didn't retrieved our layout information during a call of
+  // NotifyTSFOfLayoutChange(), it means that the TIP already gave up to
+  // retry to retrieve layout information or doesn't necessary it anymore.
+  // But don't forget that the call may have caused returning TS_E_NOLAYOUT
+  // error again.  In such case we still need to call OnLayoutChange() later.
+  if (!mHasReturnedNoLayoutError && mWaitingQueryLayout) {
+    mWaitingQueryLayout = false;
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   TSFTextStore::NotifyTSFOfLayoutChangeAgain(), "
+             "called NotifyTSFOfLayoutChange() but TIP didn't retry to "
+             "retrieve the layout information",
+             this));
+  } else {
+    MOZ_LOG(gIMELog, LogLevel::Info,
+            ("0x%p   TSFTextStore::NotifyTSFOfLayoutChangeAgain(), "
+             "called NotifyTSFOfLayoutChange()",
+             this));
+  }
+}
+
+nsresult TSFTextStore::OnUpdateCompositionInternal() {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::OnUpdateCompositionInternal(), "
+           "mDestroyed=%s, mDeferNotifyingTSFUntilNextUpdate=%s",
+           this, GetBoolName(mDestroyed),
+           GetBoolName(mDeferNotifyingTSFUntilNextUpdate)));
+
+  // There are nothing to do after destroyed.
+  if (mDestroyed) {
+    return NS_OK;
+  }
+
+  // Update cached data now because all pending events have been handled now.
+  if (mContentForTSF.isSome()) {
+    mContentForTSF->OnCompositionEventsHandled();
+  }
+
+  // If composition is completely finished both in TSF/TIP and the focused
+  // editor which may be in a remote process, we can clear the cache and don't
+  // have it until starting next composition.
+  if (mComposition.isNothing() && !IsHandlingCompositionInContent()) {
+    mDeferClearingContentForTSF = false;
+  }
+  mDeferNotifyingTSFUntilNextUpdate = false;
+  MaybeFlushPendingNotifications();
+
+  // If we're available, we should create native caret instead of IMEHandler
+  // because we may have some cache to do it.
+  if (IMEHandler::NeedsToCreateNativeCaret()) {
+    CreateNativeCaret();
+  }
+
+  return NS_OK;
+}
+
+nsresult TSFTextStore::OnMouseButtonEventInternal(
+    const IMENotification& aIMENotification) {
+  if (mDestroyed) {
+    // If this instance is already destroyed, we shouldn't notify TSF of any
+    // events.
+    return NS_OK;
+  }
+
+  if (mMouseTrackers.IsEmpty()) {
+    return NS_OK;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::OnMouseButtonEventInternal("
+           "aIMENotification={ mEventMessage=%s, mOffset=%u, mCursorPos=%s, "
+           "mCharRect=%s, mButton=%s, mButtons=%s, mModifiers=%s })",
+           this, ToChar(aIMENotification.mMouseButtonEventData.mEventMessage),
+           aIMENotification.mMouseButtonEventData.mOffset,
+           ToString(aIMENotification.mMouseButtonEventData.mCursorPos).c_str(),
+           ToString(aIMENotification.mMouseButtonEventData.mCharRect).c_str(),
+           GetMouseButtonName(aIMENotification.mMouseButtonEventData.mButton),
+           GetMouseButtonsName(aIMENotification.mMouseButtonEventData.mButtons)
+               .get(),
+           GetModifiersName(aIMENotification.mMouseButtonEventData.mModifiers)
+               .get()));
+
+  uint32_t offset = aIMENotification.mMouseButtonEventData.mOffset;
+  if (offset > static_cast<uint32_t>(LONG_MAX)) {
+    return NS_OK;
+  }
+  LayoutDeviceIntRect charRect =
+      aIMENotification.mMouseButtonEventData.mCharRect;
+  LayoutDeviceIntPoint cursorPos =
+      aIMENotification.mMouseButtonEventData.mCursorPos;
+  ULONG quadrant = 1;
+  if (charRect.Width() > 0) {
+    int32_t cursorXInChar = cursorPos.x - charRect.X();
+    quadrant = cursorXInChar * 4 / charRect.Width();
+    quadrant = (quadrant + 2) % 4;
+  }
+  ULONG edge = quadrant < 2 ? offset + 1 : offset;
+  DWORD buttonStatus = 0;
+  bool isMouseUp =
+      aIMENotification.mMouseButtonEventData.mEventMessage == eMouseUp;
+  if (!isMouseUp) {
+    switch (aIMENotification.mMouseButtonEventData.mButton) {
+      case MouseButton::ePrimary:
+        buttonStatus = MK_LBUTTON;
+        break;
+      case MouseButton::eMiddle:
+        buttonStatus = MK_MBUTTON;
+        break;
+      case MouseButton::eSecondary:
+        buttonStatus = MK_RBUTTON;
+        break;
+    }
+  }
+  if (aIMENotification.mMouseButtonEventData.mModifiers & MODIFIER_CONTROL) {
+    buttonStatus |= MK_CONTROL;
+  }
+  if (aIMENotification.mMouseButtonEventData.mModifiers & MODIFIER_SHIFT) {
+    buttonStatus |= MK_SHIFT;
+  }
+  for (size_t i = 0; i < mMouseTrackers.Length(); i++) {
+    MouseTracker& tracker = mMouseTrackers[i];
+    if (!tracker.IsUsing() || tracker.Range().isNothing() ||
+        !tracker.Range()->IsOffsetInRange(offset)) {
+      continue;
+    }
+    if (tracker.OnMouseButtonEvent(edge - tracker.Range()->StartOffset(),
+                                   quadrant, buttonStatus)) {
+      return NS_SUCCESS_EVENT_CONSUMED;
+    }
+  }
+  return NS_OK;
+}
+
+void TSFTextStore::CreateNativeCaret() {
+  MOZ_ASSERT(!IMEHandler::IsA11yHandlingNativeCaret());
+
+  IMEHandler::MaybeDestroyNativeCaret();
+
+  // Don't create native caret after destroyed.
+  if (mDestroyed) {
+    return;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::CreateNativeCaret(), mComposition=%s", this,
+           ToString(mComposition).c_str()));
+
+  Maybe<Selection>& selectionForTSF = SelectionForTSF();
+  if (MOZ_UNLIKELY(selectionForTSF.isNothing())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::CreateNativeCaret() FAILED due to "
+             "SelectionForTSF() failure",
+             this));
+    return;
+  }
+  if (!selectionForTSF->HasRange() && mComposition.isNothing()) {
+    // If there is no selection range nor composition, then, we don't have a
+    // good position to show windows of TIP...
+    // XXX It seems that storing last caret rect and using it in this case might
+    // be better?
+    MOZ_LOG(gIMELog, LogLevel::Warning,
+            ("0x%p   TSFTextStore::CreateNativeCaret() couludn't create native "
+             "caret due to no selection range",
+             this));
+    return;
+  }
+
+  WidgetQueryContentEvent queryCaretRectEvent(true, eQueryCaretRect, mWidget);
+  mWidget->InitEvent(queryCaretRectEvent);
+
+  WidgetQueryContentEvent::Options options;
+  // XXX If this is called without composition and the selection isn't
+  //     collapsed, is it OK?
+  int64_t caretOffset = selectionForTSF->HasRange()
+                            ? selectionForTSF->MaxOffset()
+                            : mComposition->StartOffset();
+  if (mComposition.isSome()) {
+    // If there is a composition, use the relative query for deciding caret
+    // position because composition might be different place from that
+    // TSFTextStore assumes.
+    options.mRelativeToInsertionPoint = true;
+    caretOffset -= mComposition->StartOffset();
+  } else if (!CanAccessActualContentDirectly()) {
+    // If TSF/TIP cannot access actual content directly, there may be pending
+    // text and/or selection changes which have not been notified TSF yet.
+    // Therefore, we should use the relative query from start of selection where
+    // TSFTextStore assumes since TSF/TIP computes the offset from our cached
+    // selection.
+    options.mRelativeToInsertionPoint = true;
+    caretOffset -= selectionForTSF->StartOffset();
+  }
+  queryCaretRectEvent.InitForQueryCaretRect(caretOffset, options);
+
+  DispatchEvent(queryCaretRectEvent);
+  if (NS_WARN_IF(queryCaretRectEvent.Failed())) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::CreateNativeCaret() FAILED due to "
+             "eQueryCaretRect failure (offset=%lld)",
+             this, caretOffset));
+    return;
+  }
+
+  if (!IMEHandler::CreateNativeCaret(static_cast<nsWindow*>(mWidget.get()),
+                                     queryCaretRectEvent.mReply->mRect)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::CreateNativeCaret() FAILED due to "
+             "IMEHandler::CreateNativeCaret() failure",
+             this));
+    return;
+  }
+}
+
+void TSFTextStore::CommitCompositionInternal(bool aDiscard) {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::CommitCompositionInternal(aDiscard=%s), "
+           "mSink=0x%p, mContext=0x%p, mComposition=%s",
+           this, GetBoolName(aDiscard), mSink.get(), mContext.get(),
+           ToString(mComposition).c_str()));
+
+  // If the document is locked, TSF will fail to commit composition since
+  // TSF needs another document lock.  So, let's put off the request.
+  // Note that TextComposition will commit composition in the focused editor
+  // with the latest composition string for web apps and waits asynchronous
+  // committing messages.  Therefore, we can and need to perform this
+  // asynchronously.
+  if (IsReadLocked()) {
+    if (mDeferCommittingComposition || mDeferCancellingComposition) {
+      MOZ_LOG(gIMELog, LogLevel::Debug,
+              ("0x%p   TSFTextStore::CommitCompositionInternal(), "
+               "does nothing because already called and waiting unlock...",
+               this));
+      return;
+    }
+    if (aDiscard) {
+      mDeferCancellingComposition = true;
+    } else {
+      mDeferCommittingComposition = true;
+    }
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("0x%p   TSFTextStore::CommitCompositionInternal(), "
+             "putting off to request to %s composition after unlocking the "
+             "document",
+             this, aDiscard ? "cancel" : "commit"));
+    return;
+  }
+
+  if (mComposition.isSome() && aDiscard) {
+    LONG endOffset = mComposition->EndOffset();
+    mComposition->SetData(EmptyString());
+    // Note that don't notify TSF of text change after this is destroyed.
+    if (mSink && !mDestroyed) {
+      TS_TEXTCHANGE textChange;
+      textChange.acpStart = mComposition->StartOffset();
+      textChange.acpOldEnd = endOffset;
+      textChange.acpNewEnd = mComposition->StartOffset();
+      MOZ_LOG(gIMELog, LogLevel::Info,
+              ("0x%p   TSFTextStore::CommitCompositionInternal(), calling"
+               "mSink->OnTextChange(0, { acpStart=%ld, acpOldEnd=%ld, "
+               "acpNewEnd=%ld })...",
+               this, textChange.acpStart, textChange.acpOldEnd,
+               textChange.acpNewEnd));
+      RefPtr<ITextStoreACPSink> sink = mSink;
+      sink->OnTextChange(0, &textChange);
+    }
+  }
+  // Terminate two contexts, the base context (mContext) and the top
+  // if the top context is not the same as the base context
+  RefPtr<ITfContext> context = mContext;
+  do {
+    if (context) {
+      RefPtr<ITfContextOwnerCompositionServices> services;
+      context->QueryInterface(IID_ITfContextOwnerCompositionServices,
+                              getter_AddRefs(services));
+      if (services) {
+        MOZ_LOG(gIMELog, LogLevel::Debug,
+                ("0x%p   TSFTextStore::CommitCompositionInternal(), "
+                 "requesting TerminateComposition() for the context 0x%p...",
+                 this, context.get()));
+        services->TerminateComposition(nullptr);
+      }
+    }
+    if (context != mContext) break;
+    if (mDocumentMgr) mDocumentMgr->GetTop(getter_AddRefs(context));
+  } while (context != mContext);
+}
+
+static bool GetCompartment(IUnknown* pUnk, const GUID& aID,
+                           ITfCompartment** aCompartment) {
+  if (!pUnk) return false;
+
+  RefPtr<ITfCompartmentMgr> compMgr;
+  pUnk->QueryInterface(IID_ITfCompartmentMgr, getter_AddRefs(compMgr));
+  if (!compMgr) return false;
+
+  return SUCCEEDED(compMgr->GetCompartment(aID, aCompartment)) &&
+         (*aCompartment) != nullptr;
+}
+
+// static
+void TSFTextStore::SetIMEOpenState(bool aState) {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("TSFTextStore::SetIMEOpenState(aState=%s)", GetBoolName(aState)));
+
+  if (!sThreadMgr) {
+    return;
+  }
+
+  RefPtr<ITfCompartment> comp = GetCompartmentForOpenClose();
+  if (NS_WARN_IF(!comp)) {
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("  TSFTextStore::SetIMEOpenState() FAILED due to"
+             "no compartment available"));
+    return;
+  }
+
+  VARIANT variant;
+  variant.vt = VT_I4;
+  variant.lVal = aState;
+  HRESULT hr = comp->SetValue(sClientId, &variant);
+  if (NS_WARN_IF(FAILED(hr))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::SetIMEOpenState() FAILED due to "
+             "ITfCompartment::SetValue() failure, hr=0x%08lX",
+             hr));
+    return;
+  }
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("  TSFTextStore::SetIMEOpenState(), setting "
+           "0x%04lX to GUID_COMPARTMENT_KEYBOARD_OPENCLOSE...",
+           variant.lVal));
+}
+
+// static
+bool TSFTextStore::GetIMEOpenState() {
+  if (!sThreadMgr) {
+    return false;
+  }
+
+  RefPtr<ITfCompartment> comp = GetCompartmentForOpenClose();
+  if (NS_WARN_IF(!comp)) {
+    return false;
+  }
+
+  VARIANT variant;
+  ::VariantInit(&variant);
+  HRESULT hr = comp->GetValue(&variant);
+  if (NS_WARN_IF(FAILED(hr))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("TSFTextStore::GetIMEOpenState() FAILED due to "
+             "ITfCompartment::GetValue() failure, hr=0x%08lX",
+             hr));
+    return false;
+  }
+  // Until IME is open in this process, the result may be empty.
+  if (variant.vt == VT_EMPTY) {
+    return false;
+  }
+  if (NS_WARN_IF(variant.vt != VT_I4)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("TSFTextStore::GetIMEOpenState() FAILED due to "
+             "invalid result of ITfCompartment::GetValue()"));
+    ::VariantClear(&variant);
+    return false;
+  }
+
+  return variant.lVal != 0;
+}
+
+// static
+void TSFTextStore::SetInputContext(nsWindow* aWidget,
+                                   const InputContext& aContext,
+                                   const InputContextAction& aAction) {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("TSFTextStore::SetInputContext(aWidget=%p, "
+           "aContext=%s, aAction.mFocusChange=%s), "
+           "sEnabledTextStore(0x%p)={ mWidget=0x%p }, ThinksHavingFocus()=%s",
+           aWidget, mozilla::ToString(aContext).c_str(),
+           GetFocusChangeName(aAction.mFocusChange), sEnabledTextStore.get(),
+           sEnabledTextStore ? sEnabledTextStore->mWidget.get() : nullptr,
+           GetBoolName(ThinksHavingFocus())));
+
+  switch (aAction.mFocusChange) {
+    case InputContextAction::WIDGET_CREATED:
+      // If this is called when the widget is created, there is nothing to do.
+      return;
+    case InputContextAction::FOCUS_NOT_CHANGED:
+    case InputContextAction::MENU_LOST_PSEUDO_FOCUS:
+      if (NS_WARN_IF(!IsInTSFMode())) {
+        return;
+      }
+      // In these cases, `NOTIFY_IME_OF_FOCUS` won't be sent.  Therefore,
+      // we need to reset text store for new state right now.
+      break;
+    default:
+      NS_WARNING_ASSERTION(IsInTSFMode(),
+                           "Why is this called when TSF is disabled?");
+      if (sEnabledTextStore) {
+        RefPtr<TSFTextStore> textStore(sEnabledTextStore);
+        textStore->mInPrivateBrowsing = aContext.mInPrivateBrowsing;
+        textStore->SetInputScope(aContext.mHTMLInputType,
+                                 aContext.mHTMLInputMode);
+        if (aContext.mURI) {
+          nsAutoCString spec;
+          if (NS_SUCCEEDED(aContext.mURI->GetSpec(spec))) {
+            CopyUTF8toUTF16(spec, textStore->mDocumentURL);
+          } else {
+            textStore->mDocumentURL.Truncate();
+          }
+        } else {
+          textStore->mDocumentURL.Truncate();
+        }
+      }
+      return;
+  }
+
+  // If focus isn't actually changed but the enabled state is changed,
+  // emulate the focus move.
+  if (!ThinksHavingFocus() && aContext.mIMEState.IsEditable()) {
+    if (!IMEHandler::GetFocusedWindow()) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("  TSFTextStore::SetInputContent() gets called to enable IME, "
+               "but IMEHandler has not received focus notification"));
+    } else {
+      MOZ_LOG(gIMELog, LogLevel::Debug,
+              ("  TSFTextStore::SetInputContent() emulates focus for IME "
+               "state change"));
+      OnFocusChange(true, aWidget, aContext);
+    }
+  } else if (ThinksHavingFocus() && !aContext.mIMEState.IsEditable()) {
+    MOZ_LOG(gIMELog, LogLevel::Debug,
+            ("  TSFTextStore::SetInputContent() emulates blur for IME "
+             "state change"));
+    OnFocusChange(false, aWidget, aContext);
+  }
+}
+
+// static
+void TSFTextStore::MarkContextAsKeyboardDisabled(ITfContext* aContext) {
+  VARIANT variant_int4_value1;
+  variant_int4_value1.vt = VT_I4;
+  variant_int4_value1.lVal = 1;
+
+  RefPtr<ITfCompartment> comp;
+  if (!GetCompartment(aContext, GUID_COMPARTMENT_KEYBOARD_DISABLED,
+                      getter_AddRefs(comp))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("TSFTextStore::MarkContextAsKeyboardDisabled() failed"
+             "aContext=0x%p...",
+             aContext));
+    return;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("TSFTextStore::MarkContextAsKeyboardDisabled(), setting "
+           "to disable context 0x%p...",
+           aContext));
+  comp->SetValue(sClientId, &variant_int4_value1);
+}
+
+// static
+void TSFTextStore::MarkContextAsEmpty(ITfContext* aContext) {
+  VARIANT variant_int4_value1;
+  variant_int4_value1.vt = VT_I4;
+  variant_int4_value1.lVal = 1;
+
+  RefPtr<ITfCompartment> comp;
+  if (!GetCompartment(aContext, GUID_COMPARTMENT_EMPTYCONTEXT,
+                      getter_AddRefs(comp))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("TSFTextStore::MarkContextAsEmpty() failed"
+             "aContext=0x%p...",
+             aContext));
+    return;
+  }
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("TSFTextStore::MarkContextAsEmpty(), setting "
+           "to mark empty context 0x%p...",
+           aContext));
+  comp->SetValue(sClientId, &variant_int4_value1);
+}
+
+// static
+void TSFTextStore::Initialize() {
+  MOZ_LOG(gIMELog, LogLevel::Info, ("TSFTextStore::Initialize() is called..."));
+
+  if (sThreadMgr) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::Initialize() FAILED due to already initialized"));
+    return;
+  }
+
+  const bool enableTsf = StaticPrefs::intl_tsf_enabled_AtStartup();
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("  TSFTextStore::Initialize(), TSF is %s",
+           enableTsf ? "enabled" : "disabled"));
+  if (!enableTsf) {
+    return;
+  }
+
+  RefPtr<ITfThreadMgr> threadMgr;
+  HRESULT hr =
+      ::CoCreateInstance(CLSID_TF_ThreadMgr, nullptr, CLSCTX_INPROC_SERVER,
+                         IID_ITfThreadMgr, getter_AddRefs(threadMgr));
+  if (FAILED(hr) || !threadMgr) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::Initialize() FAILED to "
+             "create the thread manager, hr=0x%08lX",
+             hr));
+    return;
+  }
+
+  hr = threadMgr->Activate(&sClientId);
+  if (FAILED(hr)) {
+    MOZ_LOG(
+        gIMELog, LogLevel::Error,
+        ("  TSFTextStore::Initialize() FAILED to activate, hr=0x%08lX", hr));
+    return;
+  }
+
+  RefPtr<ITfDocumentMgr> disabledDocumentMgr;
+  hr = threadMgr->CreateDocumentMgr(getter_AddRefs(disabledDocumentMgr));
+  if (FAILED(hr) || !disabledDocumentMgr) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::Initialize() FAILED to create "
+             "a document manager for disabled mode, hr=0x%08lX",
+             hr));
+    return;
+  }
+
+  RefPtr<ITfContext> disabledContext;
+  DWORD editCookie = 0;
+  hr = disabledDocumentMgr->CreateContext(
+      sClientId, 0, nullptr, getter_AddRefs(disabledContext), &editCookie);
+  if (FAILED(hr) || !disabledContext) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::Initialize() FAILED to create "
+             "a context for disabled mode, hr=0x%08lX",
+             hr));
+    return;
+  }
+
+  MarkContextAsKeyboardDisabled(disabledContext);
+  MarkContextAsEmpty(disabledContext);
+
+  sThreadMgr = threadMgr;
+  sDisabledDocumentMgr = disabledDocumentMgr;
+  sDisabledContext = disabledContext;
+
+  MOZ_LOG(gIMELog, LogLevel::Info,
+          ("  TSFTextStore::Initialize(), sThreadMgr=0x%p, "
+           "sClientId=0x%08lX, sDisabledDocumentMgr=0x%p, sDisabledContext=%p",
+           sThreadMgr.get(), sClientId, sDisabledDocumentMgr.get(),
+           sDisabledContext.get()));
+}
+
+// static
+already_AddRefed<ITfThreadMgr> TSFTextStore::GetThreadMgr() {
+  RefPtr<ITfThreadMgr> threadMgr = sThreadMgr;
+  return threadMgr.forget();
+}
+
+// static
+already_AddRefed<ITfMessagePump> TSFTextStore::GetMessagePump() {
+  static bool sInitialized = false;
+  if (!sThreadMgr) {
+    return nullptr;
+  }
+  if (sMessagePump) {
+    RefPtr<ITfMessagePump> messagePump = sMessagePump;
+    return messagePump.forget();
+  }
+  // If it tried to retrieve ITfMessagePump from sThreadMgr but it failed,
+  // we shouldn't retry it at every message due to performance reason.
+  // Although this shouldn't occur actually.
+  if (sInitialized) {
+    return nullptr;
+  }
+  sInitialized = true;
+
+  RefPtr<ITfMessagePump> messagePump;
+  HRESULT hr = sThreadMgr->QueryInterface(IID_ITfMessagePump,
+                                          getter_AddRefs(messagePump));
+  if (NS_WARN_IF(FAILED(hr)) || NS_WARN_IF(!messagePump)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("TSFTextStore::GetMessagePump() FAILED to "
+             "QI message pump from the thread manager, hr=0x%08lX",
+             hr));
+    return nullptr;
+  }
+  sMessagePump = messagePump;
+  return messagePump.forget();
+}
+
+// static
+already_AddRefed<ITfDisplayAttributeMgr>
+TSFTextStore::GetDisplayAttributeMgr() {
+  RefPtr<ITfDisplayAttributeMgr> displayAttributeMgr;
+  if (sDisplayAttrMgr) {
+    displayAttributeMgr = sDisplayAttrMgr;
+    return displayAttributeMgr.forget();
+  }
+
+  HRESULT hr = ::CoCreateInstance(
+      CLSID_TF_DisplayAttributeMgr, nullptr, CLSCTX_INPROC_SERVER,
+      IID_ITfDisplayAttributeMgr, getter_AddRefs(displayAttributeMgr));
+  if (NS_WARN_IF(FAILED(hr)) || NS_WARN_IF(!displayAttributeMgr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("TSFTextStore::GetDisplayAttributeMgr() FAILED to create "
+             "a display attribute manager instance, hr=0x%08lX",
+             hr));
+    return nullptr;
+  }
+  sDisplayAttrMgr = displayAttributeMgr;
+  return displayAttributeMgr.forget();
+}
+
+// static
+already_AddRefed<ITfCategoryMgr> TSFTextStore::GetCategoryMgr() {
+  RefPtr<ITfCategoryMgr> categoryMgr;
+  if (sCategoryMgr) {
+    categoryMgr = sCategoryMgr;
+    return categoryMgr.forget();
+  }
+  HRESULT hr =
+      ::CoCreateInstance(CLSID_TF_CategoryMgr, nullptr, CLSCTX_INPROC_SERVER,
+                         IID_ITfCategoryMgr, getter_AddRefs(categoryMgr));
+  if (NS_WARN_IF(FAILED(hr)) || NS_WARN_IF(!categoryMgr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("TSFTextStore::GetCategoryMgr() FAILED to create "
+             "a category manager instance, hr=0x%08lX",
+             hr));
+    return nullptr;
+  }
+  sCategoryMgr = categoryMgr;
+  return categoryMgr.forget();
+}
+
+// static
+already_AddRefed<ITfCompartment> TSFTextStore::GetCompartmentForOpenClose() {
+  if (sCompartmentForOpenClose) {
+    RefPtr<ITfCompartment> compartment = sCompartmentForOpenClose;
+    return compartment.forget();
+  }
+
+  if (!sThreadMgr) {
+    return nullptr;
+  }
+
+  RefPtr<ITfCompartmentMgr> compartmentMgr;
+  HRESULT hr = sThreadMgr->QueryInterface(IID_ITfCompartmentMgr,
+                                          getter_AddRefs(compartmentMgr));
+  if (NS_WARN_IF(FAILED(hr)) || NS_WARN_IF(!compartmentMgr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("TSFTextStore::GetCompartmentForOpenClose() FAILED due to"
+             "sThreadMgr not having ITfCompartmentMgr, hr=0x%08lX",
+             hr));
+    return nullptr;
+  }
+
+  RefPtr<ITfCompartment> compartment;
+  hr = compartmentMgr->GetCompartment(GUID_COMPARTMENT_KEYBOARD_OPENCLOSE,
+                                      getter_AddRefs(compartment));
+  if (NS_WARN_IF(FAILED(hr)) || NS_WARN_IF(!compartment)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("TSFTextStore::GetCompartmentForOpenClose() FAILED due to"
+             "ITfCompartmentMgr::GetCompartment() failuere, hr=0x%08lX",
+             hr));
+    return nullptr;
+  }
+
+  sCompartmentForOpenClose = compartment;
+  return compartment.forget();
+}
+
+// static
+already_AddRefed<ITfInputProcessorProfiles>
+TSFTextStore::GetInputProcessorProfiles() {
+  RefPtr<ITfInputProcessorProfiles> inputProcessorProfiles;
+  if (sInputProcessorProfiles) {
+    inputProcessorProfiles = sInputProcessorProfiles;
+    return inputProcessorProfiles.forget();
+  }
+  // XXX MSDN documents that ITfInputProcessorProfiles is available only on
+  //     desktop apps.  However, there is no known way to obtain
+  //     ITfInputProcessorProfileMgr instance without ITfInputProcessorProfiles
+  //     instance.
+  HRESULT hr = ::CoCreateInstance(
+      CLSID_TF_InputProcessorProfiles, nullptr, CLSCTX_INPROC_SERVER,
+      IID_ITfInputProcessorProfiles, getter_AddRefs(inputProcessorProfiles));
+  if (NS_WARN_IF(FAILED(hr)) || NS_WARN_IF(!inputProcessorProfiles)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("TSFTextStore::GetInputProcessorProfiles() FAILED to create input "
+             "processor profiles, hr=0x%08lX",
+             hr));
+    return nullptr;
+  }
+  sInputProcessorProfiles = inputProcessorProfiles;
+  return inputProcessorProfiles.forget();
+}
+
+// static
+void TSFTextStore::Terminate() {
+  MOZ_LOG(gIMELog, LogLevel::Info, ("TSFTextStore::Terminate()"));
+
+  TSFStaticSink::Shutdown();
+
+  sDisplayAttrMgr = nullptr;
+  sCategoryMgr = nullptr;
+  sEnabledTextStore = nullptr;
+  sDisabledDocumentMgr = nullptr;
+  sDisabledContext = nullptr;
+  sCompartmentForOpenClose = nullptr;
+  sInputProcessorProfiles = nullptr;
+  sClientId = 0;
+  if (sThreadMgr) {
+    sThreadMgr->Deactivate();
+    sThreadMgr = nullptr;
+    sMessagePump = nullptr;
+    sKeystrokeMgr = nullptr;
+  }
+}
+
+// static
+bool TSFTextStore::ProcessRawKeyMessage(const MSG& aMsg) {
+  if (!sThreadMgr) {
+    return false;  // not in TSF mode
+  }
+  static bool sInitialized = false;
+  if (!sKeystrokeMgr) {
+    // If it tried to retrieve ITfKeystrokeMgr from sThreadMgr but it failed,
+    // we shouldn't retry it at every keydown nor keyup due to performance
+    // reason.  Although this shouldn't occur actually.
+    if (sInitialized) {
+      return false;
+    }
+    sInitialized = true;
+    RefPtr<ITfKeystrokeMgr> keystrokeMgr;
+    HRESULT hr = sThreadMgr->QueryInterface(IID_ITfKeystrokeMgr,
+                                            getter_AddRefs(keystrokeMgr));
+    if (NS_WARN_IF(FAILED(hr)) || NS_WARN_IF(!keystrokeMgr)) {
+      MOZ_LOG(gIMELog, LogLevel::Error,
+              ("TSFTextStore::ProcessRawKeyMessage() FAILED to "
+               "QI keystroke manager from the thread manager, hr=0x%08lX",
+               hr));
+      return false;
+    }
+    sKeystrokeMgr = keystrokeMgr.forget();
+  }
+
+  if (aMsg.message == WM_KEYDOWN) {
+    RefPtr<TSFTextStore> textStore(sEnabledTextStore);
+    if (textStore) {
+      textStore->OnStartToHandleKeyMessage();
+      if (NS_WARN_IF(textStore != sEnabledTextStore)) {
+        // Let's handle the key message with new focused TSFTextStore.
+        textStore = sEnabledTextStore;
+      }
+    }
+    AutoRestore<const MSG*> savePreviousKeyMsg(sHandlingKeyMsg);
+    AutoRestore<bool> saveKeyEventDispatched(sIsKeyboardEventDispatched);
+    sHandlingKeyMsg = &aMsg;
+    sIsKeyboardEventDispatched = false;
+    BOOL eaten;
+    RefPtr<ITfKeystrokeMgr> keystrokeMgr = sKeystrokeMgr;
+    HRESULT hr = keystrokeMgr->TestKeyDown(aMsg.wParam, aMsg.lParam, &eaten);
+    if (FAILED(hr) || !sKeystrokeMgr || !eaten) {
+      return false;
+    }
+    hr = keystrokeMgr->KeyDown(aMsg.wParam, aMsg.lParam, &eaten);
+    if (textStore) {
+      textStore->OnEndHandlingKeyMessage(!!eaten);
+    }
+    return SUCCEEDED(hr) &&
+           (eaten || !sKeystrokeMgr || sIsKeyboardEventDispatched);
+  }
+  if (aMsg.message == WM_KEYUP) {
+    RefPtr<TSFTextStore> textStore(sEnabledTextStore);
+    if (textStore) {
+      textStore->OnStartToHandleKeyMessage();
+      if (NS_WARN_IF(textStore != sEnabledTextStore)) {
+        // Let's handle the key message with new focused TSFTextStore.
+        textStore = sEnabledTextStore;
+      }
+    }
+    AutoRestore<const MSG*> savePreviousKeyMsg(sHandlingKeyMsg);
+    AutoRestore<bool> saveKeyEventDispatched(sIsKeyboardEventDispatched);
+    sHandlingKeyMsg = &aMsg;
+    sIsKeyboardEventDispatched = false;
+    BOOL eaten;
+    RefPtr<ITfKeystrokeMgr> keystrokeMgr = sKeystrokeMgr;
+    HRESULT hr = keystrokeMgr->TestKeyUp(aMsg.wParam, aMsg.lParam, &eaten);
+    if (FAILED(hr) || !sKeystrokeMgr || !eaten) {
+      return false;
+    }
+    hr = keystrokeMgr->KeyUp(aMsg.wParam, aMsg.lParam, &eaten);
+    if (textStore) {
+      textStore->OnEndHandlingKeyMessage(!!eaten);
+    }
+    return SUCCEEDED(hr) &&
+           (eaten || !sKeystrokeMgr || sIsKeyboardEventDispatched);
+  }
+  return false;
+}
+
+// static
+void TSFTextStore::ProcessMessage(nsWindow* aWindow, UINT aMessage,
+                                  WPARAM& aWParam, LPARAM& aLParam,
+                                  MSGResult& aResult) {
+  switch (aMessage) {
+    case WM_IME_SETCONTEXT:
+      // If a windowless plugin had focus and IME was handled on it, composition
+      // window was set the position.  After that, even in TSF mode, WinXP keeps
+      // to use composition window at the position if the active IME is not
+      // aware TSF.  For avoiding this issue, we need to hide the composition
+      // window here.
+      if (aWParam) {
+        aLParam &= ~ISC_SHOWUICOMPOSITIONWINDOW;
+      }
+      break;
+    case WM_ENTERIDLE:
+      // When an modal dialog such as a file picker is open, composition
+      // should be committed because IME might be used on it.
+      if (!IsComposingOn(aWindow)) {
+        break;
+      }
+      CommitComposition(false);
+      break;
+    case MOZ_WM_NOTIY_TSF_OF_LAYOUT_CHANGE: {
+      TSFTextStore* maybeTextStore = reinterpret_cast<TSFTextStore*>(aWParam);
+      if (maybeTextStore == sEnabledTextStore) {
+        RefPtr<TSFTextStore> textStore(maybeTextStore);
+        textStore->NotifyTSFOfLayoutChangeAgain();
+      }
+      break;
+    }
+  }
+}
+
+// static
+bool TSFTextStore::IsIMM_IMEActive() {
+  return TSFStaticSink::IsIMM_IMEActive();
+}
+
+// static
+bool TSFTextStore::IsMSJapaneseIMEActive() {
+  return TSFStaticSink::IsMSJapaneseIMEActive();
+}
+
+// static
+bool TSFTextStore::IsGoogleJapaneseInputActive() {
+  return TSFStaticSink::IsGoogleJapaneseInputActive();
+}
+
+// static
+bool TSFTextStore::IsATOKActive() { return TSFStaticSink::IsATOKActive(); }
+
+/******************************************************************************
+ *  TSFTextStore::Content
+ *****************************************************************************/
+
+const nsDependentSubstring TSFTextStore::Content::GetSelectedText() const {
+  if (NS_WARN_IF(mSelection.isNothing())) {
+    return nsDependentSubstring();
+  }
+  return GetSubstring(static_cast<uint32_t>(mSelection->StartOffset()),
+                      static_cast<uint32_t>(mSelection->Length()));
+}
+
+const nsDependentSubstring TSFTextStore::Content::GetSubstring(
+    uint32_t aStart, uint32_t aLength) const {
+  return nsDependentSubstring(mText, aStart, aLength);
+}
+
+void TSFTextStore::Content::ReplaceSelectedTextWith(const nsAString& aString) {
+  if (NS_WARN_IF(mSelection.isNothing())) {
+    return;
+  }
+  ReplaceTextWith(mSelection->StartOffset(), mSelection->Length(), aString);
+}
+
+inline uint32_t FirstDifferentCharOffset(const nsAString& aStr1,
+                                         const nsAString& aStr2) {
+  MOZ_ASSERT(aStr1 != aStr2);
+  uint32_t i = 0;
+  uint32_t minLength = std::min(aStr1.Length(), aStr2.Length());
+  for (; i < minLength && aStr1[i] == aStr2[i]; i++) {
+    /* nothing to do */
+  }
+  return i;
+}
+
+void TSFTextStore::Content::ReplaceTextWith(LONG aStart, LONG aLength,
+                                            const nsAString& aReplaceString) {
+  MOZ_ASSERT(aStart >= 0);
+  MOZ_ASSERT(aLength >= 0);
+  const nsDependentSubstring replacedString = GetSubstring(
+      static_cast<uint32_t>(aStart), static_cast<uint32_t>(aLength));
+  if (aReplaceString != replacedString) {
+    uint32_t firstDifferentOffset = mMinModifiedOffset.valueOr(UINT32_MAX);
+    if (mComposition.isSome()) {
+      // Emulate text insertion during compositions, because during a
+      // composition, editor expects the whole composition string to
+      // be sent in eCompositionChange, not just the inserted part.
+      // The actual eCompositionChange will be sent in SetSelection
+      // or OnUpdateComposition.
+      MOZ_ASSERT(aStart >= mComposition->StartOffset());
+      MOZ_ASSERT(aStart + aLength <= mComposition->EndOffset());
+      mComposition->ReplaceData(
+          static_cast<uint32_t>(aStart - mComposition->StartOffset()),
+          static_cast<uint32_t>(aLength), aReplaceString);
+      // TIP may set composition string twice or more times during a document
+      // lock.  Therefore, we should compute the first difference offset with
+      // mLastComposition.
+      if (mLastComposition.isNothing()) {
+        firstDifferentOffset = mComposition->StartOffset();
+      } else if (mComposition->DataRef() != mLastComposition->DataRef()) {
+        firstDifferentOffset =
+            mComposition->StartOffset() +
+            FirstDifferentCharOffset(mComposition->DataRef(),
+                                     mLastComposition->DataRef());
+        // The previous change to the composition string is canceled.
+        if (mMinModifiedOffset.isSome() &&
+            mMinModifiedOffset.value() >=
+                static_cast<uint32_t>(mComposition->StartOffset()) &&
+            mMinModifiedOffset.value() < firstDifferentOffset) {
+          mMinModifiedOffset = Some(firstDifferentOffset);
+        }
+      } else if (mMinModifiedOffset.isSome() &&
+                 mMinModifiedOffset.value() < static_cast<uint32_t>(LONG_MAX) &&
+                 mComposition->IsOffsetInRange(
+                     static_cast<long>(mMinModifiedOffset.value()))) {
+        // The previous change to the composition string is canceled.
+        firstDifferentOffset = mComposition->EndOffset();
+        mMinModifiedOffset = Some(firstDifferentOffset);
+      }
+      mLatestCompositionRange = Some(mComposition->CreateStartAndEndOffsets());
+      MOZ_LOG(
+          gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::Content::ReplaceTextWith(aStart=%ld, "
+           "aLength=%ld, aReplaceString=\"%s\"), mComposition=%s, "
+           "mLastComposition=%s, mMinModifiedOffset=%s, "
+           "firstDifferentOffset=%u",
+           this, aStart, aLength, GetEscapedUTF8String(aReplaceString).get(),
+           ToString(mComposition).c_str(), ToString(mLastComposition).c_str(),
+           ToString(mMinModifiedOffset).c_str(), firstDifferentOffset));
+    } else {
+      firstDifferentOffset =
+          static_cast<uint32_t>(aStart) +
+          FirstDifferentCharOffset(aReplaceString, replacedString);
+    }
+    mMinModifiedOffset =
+        mMinModifiedOffset.isNothing()
+            ? Some(firstDifferentOffset)
+            : Some(std::min(mMinModifiedOffset.value(), firstDifferentOffset));
+    mText.Replace(static_cast<uint32_t>(aStart), static_cast<uint32_t>(aLength),
+                  aReplaceString);
+  }
+  // Selection should be collapsed at the end of the inserted string.
+  mSelection = Some(TSFTextStore::Selection(static_cast<uint32_t>(aStart) +
+                                            aReplaceString.Length()));
+}
+
+void TSFTextStore::Content::StartComposition(
+    ITfCompositionView* aCompositionView, const PendingAction& aCompStart,
+    bool aPreserveSelection) {
+  MOZ_ASSERT(aCompositionView);
+  MOZ_ASSERT(mComposition.isNothing());
+  MOZ_ASSERT(aCompStart.mType == PendingAction::Type::eCompositionStart);
+
+  mComposition.reset();  // Avoid new crash in the beta and nightly channels.
+  mComposition.emplace(
+      aCompositionView, aCompStart.mSelectionStart,
+      GetSubstring(static_cast<uint32_t>(aCompStart.mSelectionStart),
+                   static_cast<uint32_t>(aCompStart.mSelectionLength)));
+  mLatestCompositionRange = Some(mComposition->CreateStartAndEndOffsets());
+  if (!aPreserveSelection) {
+    // XXX Do we need to set a new writing-mode here when setting a new
+    // selection? Currently, we just preserve the existing value.
+    WritingMode writingMode =
+        mSelection.isNothing() ? WritingMode() : mSelection->WritingModeRef();
+    mSelection = Some(TSFTextStore::Selection(mComposition->StartOffset(),
+                                              mComposition->Length(), false,
+                                              writingMode));
+  }
+}
+
+void TSFTextStore::Content::RestoreCommittedComposition(
+    ITfCompositionView* aCompositionView,
+    const PendingAction& aCanceledCompositionEnd) {
+  MOZ_ASSERT(aCompositionView);
+  MOZ_ASSERT(mComposition.isNothing());
+  MOZ_ASSERT(aCanceledCompositionEnd.mType ==
+             PendingAction::Type::eCompositionEnd);
+  MOZ_ASSERT(
+      GetSubstring(
+          static_cast<uint32_t>(aCanceledCompositionEnd.mSelectionStart),
+          static_cast<uint32_t>(aCanceledCompositionEnd.mData.Length())) ==
+      aCanceledCompositionEnd.mData);
+
+  // Restore the committed string as composing string.
+  mComposition.reset();  // Avoid new crash in the beta and nightly channels.
+  mComposition.emplace(aCompositionView,
+                       aCanceledCompositionEnd.mSelectionStart,
+                       aCanceledCompositionEnd.mData);
+  mLatestCompositionRange = Some(mComposition->CreateStartAndEndOffsets());
+}
+
+void TSFTextStore::Content::EndComposition(const PendingAction& aCompEnd) {
+  MOZ_ASSERT(mComposition.isSome());
+  MOZ_ASSERT(aCompEnd.mType == PendingAction::Type::eCompositionEnd);
+
+  if (mComposition.isNothing()) {
+    return;  // Avoid new crash in the beta and nightly channels.
+  }
+
+  mSelection = Some(TSFTextStore::Selection(mComposition->StartOffset() +
+                                            aCompEnd.mData.Length()));
+  mComposition.reset();
+}
+
+/******************************************************************************
+ *  TSFTextStore::MouseTracker
+ *****************************************************************************/
+
+TSFTextStore::MouseTracker::MouseTracker() : mCookie(kInvalidCookie) {}
+
+HRESULT
+TSFTextStore::MouseTracker::Init(TSFTextStore* aTextStore) {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::MouseTracker::Init(aTextStore=0x%p), "
+           "aTextStore->mMouseTrackers.Length()=%zu",
+           this, aTextStore, aTextStore->mMouseTrackers.Length()));
+
+  if (&aTextStore->mMouseTrackers.LastElement() != this) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::MouseTracker::Init() FAILED due to "
+             "this is not the last element of mMouseTrackers",
+             this));
+    return E_FAIL;
+  }
+  if (aTextStore->mMouseTrackers.Length() > kInvalidCookie) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::MouseTracker::Init() FAILED due to "
+             "no new cookie available",
+             this));
+    return E_FAIL;
+  }
+  MOZ_ASSERT(!aTextStore->mMouseTrackers.IsEmpty(),
+             "This instance must be in TSFTextStore::mMouseTrackers");
+  mCookie = static_cast<DWORD>(aTextStore->mMouseTrackers.Length() - 1);
+  return S_OK;
+}
+
+HRESULT
+TSFTextStore::MouseTracker::AdviseSink(TSFTextStore* aTextStore,
+                                       ITfRangeACP* aTextRange,
+                                       ITfMouseSink* aMouseSink) {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::MouseTracker::AdviseSink(aTextStore=0x%p, "
+           "aTextRange=0x%p, aMouseSink=0x%p), mCookie=%ld, mSink=0x%p",
+           this, aTextStore, aTextRange, aMouseSink, mCookie, mSink.get()));
+  MOZ_ASSERT(mCookie != kInvalidCookie, "This hasn't been initalized?");
+
+  if (mSink) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::MouseTracker::AdviseMouseSink() FAILED "
+             "due to already being used",
+             this));
+    return E_FAIL;
+  }
+
+  MOZ_ASSERT(mRange.isNothing());
+
+  LONG start = 0, length = 0;
+  HRESULT hr = aTextRange->GetExtent(&start, &length);
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::MouseTracker::AdviseMouseSink() FAILED "
+             "due to failure of ITfRangeACP::GetExtent()",
+             this));
+    return hr;
+  }
+
+  if (start < 0 || length <= 0 || start + length > LONG_MAX) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::MouseTracker::AdviseMouseSink() FAILED "
+             "due to odd result of ITfRangeACP::GetExtent(), "
+             "start=%ld, length=%ld",
+             this, start, length));
+    return E_INVALIDARG;
+  }
+
+  nsAutoString textContent;
+  if (NS_WARN_IF(!aTextStore->GetCurrentText(textContent))) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::MouseTracker::AdviseMouseSink() FAILED "
+             "due to failure of TSFTextStore::GetCurrentText()",
+             this));
+    return E_FAIL;
+  }
+
+  if (textContent.Length() <= static_cast<uint32_t>(start) ||
+      textContent.Length() < static_cast<uint32_t>(start + length)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("0x%p   TSFTextStore::MouseTracker::AdviseMouseSink() FAILED "
+             "due to out of range, start=%ld, length=%ld, "
+             "textContent.Length()=%zu",
+             this, start, length, textContent.Length()));
+    return E_INVALIDARG;
+  }
+
+  mRange.emplace(start, start + length);
+
+  mSink = aMouseSink;
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::MouseTracker::AdviseMouseSink(), "
+           "succeeded, mRange=%s, textContent.Length()=%zu",
+           this, ToString(mRange).c_str(), textContent.Length()));
+  return S_OK;
+}
+
+void TSFTextStore::MouseTracker::UnadviseSink() {
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::MouseTracker::UnadviseSink(), "
+           "mCookie=%ld, mSink=0x%p, mRange=%s",
+           this, mCookie, mSink.get(), ToString(mRange).c_str()));
+  mSink = nullptr;
+  mRange.reset();
+}
+
+bool TSFTextStore::MouseTracker::OnMouseButtonEvent(ULONG aEdge,
+                                                    ULONG aQuadrant,
+                                                    DWORD aButtonStatus) {
+  MOZ_ASSERT(IsUsing(), "The caller must check before calling OnMouseEvent()");
+
+  BOOL eaten = FALSE;
+  RefPtr<ITfMouseSink> sink = mSink;
+  HRESULT hr = sink->OnMouseEvent(aEdge, aQuadrant, aButtonStatus, &eaten);
+
+  MOZ_LOG(gIMELog, LogLevel::Debug,
+          ("0x%p   TSFTextStore::MouseTracker::OnMouseEvent(aEdge=%ld, "
+           "aQuadrant=%ld, aButtonStatus=0x%08lX), hr=0x%08lX, eaten=%s",
+           this, aEdge, aQuadrant, aButtonStatus, hr, GetBoolName(!!eaten)));
+
+  return SUCCEEDED(hr) && eaten;
+}
+
+#ifdef DEBUG
+// static
+bool TSFTextStore::CurrentKeyboardLayoutHasIME() {
+  RefPtr<ITfInputProcessorProfiles> inputProcessorProfiles =
+      TSFTextStore::GetInputProcessorProfiles();
+  if (!inputProcessorProfiles) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("TSFTextStore::CurrentKeyboardLayoutHasIME() FAILED due to "
+             "there is no input processor profiles instance"));
+    return false;
+  }
+  RefPtr<ITfInputProcessorProfileMgr> profileMgr;
+  HRESULT hr = inputProcessorProfiles->QueryInterface(
+      IID_ITfInputProcessorProfileMgr, getter_AddRefs(profileMgr));
+  if (FAILED(hr) || !profileMgr) {
+    // On Windows Vista or later, ImmIsIME() API always returns true.
+    // If we failed to obtain the profile manager, we cannot know if current
+    // keyboard layout has IME.
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::CurrentKeyboardLayoutHasIME() FAILED to query "
+             "ITfInputProcessorProfileMgr"));
+    return false;
+  }
+
+  TF_INPUTPROCESSORPROFILE profile;
+  hr = profileMgr->GetActiveProfile(GUID_TFCAT_TIP_KEYBOARD, &profile);
+  if (hr == S_FALSE) {
+    return false;  // not found or not active
+  }
+  if (FAILED(hr)) {
+    MOZ_LOG(gIMELog, LogLevel::Error,
+            ("  TSFTextStore::CurrentKeyboardLayoutHasIME() FAILED to retreive "
+             "active profile"));
+    return false;
+  }
+  return (profile.dwProfileType == TF_PROFILETYPE_INPUTPROCESSOR);
+}
+#endif  // #ifdef DEBUG
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/TSFTextStore.h b/widget/windows/TSFTextStore.h
new file mode 100644
index 0000000000..17358a488d
--- /dev/null
+++ b/widget/windows/TSFTextStore.h
@@ -0,0 +1,1161 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef TSFTextStore_h_
+#define TSFTextStore_h_
+
+#include "nsCOMPtr.h"
+#include "nsIWidget.h"
+#include "nsString.h"
+#include "nsWindow.h"
+
+#include "WinUtils.h"
+#include "WritingModes.h"
+
+#include "mozilla/Attributes.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/TextRange.h"
+#include "mozilla/WindowsVersion.h"
+#include "mozilla/widget/IMEData.h"
+
+#include <msctf.h>
+#include <textstor.h>
+
+// GUID_PROP_INPUTSCOPE is declared in inputscope.h using INIT_GUID.
+// With initguid.h, we get its instance instead of extern declaration.
+#ifdef INPUTSCOPE_INIT_GUID
+#  include <initguid.h>
+#endif
+#ifdef TEXTATTRS_INIT_GUID
+#  include <tsattrs.h>
+#endif
+#include <inputscope.h>
+
+// TSF InputScope, for earlier SDK 8
+#define IS_SEARCH static_cast<InputScope>(50)
+
+struct ITfThreadMgr;
+struct ITfDocumentMgr;
+struct ITfDisplayAttributeMgr;
+struct ITfCategoryMgr;
+class nsWindow;
+
+inline std::ostream& operator<<(std::ostream& aStream,
+                                const TS_SELECTIONSTYLE& aSelectionStyle) {
+  const char* ase = "Unknown";
+  switch (aSelectionStyle.ase) {
+    case TS_AE_START:
+      ase = "TS_AE_START";
+      break;
+    case TS_AE_END:
+      ase = "TS_AE_END";
+      break;
+    case TS_AE_NONE:
+      ase = "TS_AE_NONE";
+      break;
+  }
+  aStream << "{ ase=" << ase << ", fInterimChar="
+          << (aSelectionStyle.fInterimChar ? "TRUE" : "FALSE") << " }";
+  return aStream;
+}
+
+inline std::ostream& operator<<(std::ostream& aStream,
+                                const TS_SELECTION_ACP& aACP) {
+  aStream << "{ acpStart=" << aACP.acpStart << ", acpEnd=" << aACP.acpEnd
+          << ", style=" << mozilla::ToString(aACP.style).c_str() << " }";
+  return aStream;
+}
+
+namespace mozilla {
+namespace widget {
+
+class TSFStaticSink;
+struct MSGResult;
+
+/*
+ * Text Services Framework text store
+ */
+
+class TSFTextStore final : public ITextStoreACP,
+                           public ITfContextOwnerCompositionSink,
+                           public ITfMouseTrackerACP {
+  friend class TSFStaticSink;
+
+ private:
+  typedef IMENotification::SelectionChangeDataBase SelectionChangeDataBase;
+  typedef IMENotification::SelectionChangeData SelectionChangeData;
+  typedef IMENotification::TextChangeDataBase TextChangeDataBase;
+  typedef IMENotification::TextChangeData TextChangeData;
+
+ public: /*IUnknown*/
+  STDMETHODIMP QueryInterface(REFIID, void**);
+
+  NS_INLINE_DECL_IUNKNOWN_REFCOUNTING(TSFTextStore)
+
+ public: /*ITextStoreACP*/
+  STDMETHODIMP AdviseSink(REFIID, IUnknown*, DWORD);
+  STDMETHODIMP UnadviseSink(IUnknown*);
+  STDMETHODIMP RequestLock(DWORD, HRESULT*);
+  STDMETHODIMP GetStatus(TS_STATUS*);
+  STDMETHODIMP QueryInsert(LONG, LONG, ULONG, LONG*, LONG*);
+  STDMETHODIMP GetSelection(ULONG, ULONG, TS_SELECTION_ACP*, ULONG*);
+  STDMETHODIMP SetSelection(ULONG, const TS_SELECTION_ACP*);
+  STDMETHODIMP GetText(LONG, LONG, WCHAR*, ULONG, ULONG*, TS_RUNINFO*, ULONG,
+                       ULONG*, LONG*);
+  STDMETHODIMP SetText(DWORD, LONG, LONG, const WCHAR*, ULONG, TS_TEXTCHANGE*);
+  STDMETHODIMP GetFormattedText(LONG, LONG, IDataObject**);
+  STDMETHODIMP GetEmbedded(LONG, REFGUID, REFIID, IUnknown**);
+  STDMETHODIMP QueryInsertEmbedded(const GUID*, const FORMATETC*, BOOL*);
+  STDMETHODIMP InsertEmbedded(DWORD, LONG, LONG, IDataObject*, TS_TEXTCHANGE*);
+  STDMETHODIMP RequestSupportedAttrs(DWORD, ULONG, const TS_ATTRID*);
+  STDMETHODIMP RequestAttrsAtPosition(LONG, ULONG, const TS_ATTRID*, DWORD);
+  STDMETHODIMP RequestAttrsTransitioningAtPosition(LONG, ULONG,
+                                                   const TS_ATTRID*, DWORD);
+  STDMETHODIMP FindNextAttrTransition(LONG, LONG, ULONG, const TS_ATTRID*,
+                                      DWORD, LONG*, BOOL*, LONG*);
+  STDMETHODIMP RetrieveRequestedAttrs(ULONG, TS_ATTRVAL*, ULONG*);
+  STDMETHODIMP GetEndACP(LONG*);
+  STDMETHODIMP GetActiveView(TsViewCookie*);
+  STDMETHODIMP GetACPFromPoint(TsViewCookie, const POINT*, DWORD, LONG*);
+  STDMETHODIMP GetTextExt(TsViewCookie, LONG, LONG, RECT*, BOOL*);
+  STDMETHODIMP GetScreenExt(TsViewCookie, RECT*);
+  STDMETHODIMP GetWnd(TsViewCookie, HWND*);
+  STDMETHODIMP InsertTextAtSelection(DWORD, const WCHAR*, ULONG, LONG*, LONG*,
+                                     TS_TEXTCHANGE*);
+  STDMETHODIMP InsertEmbeddedAtSelection(DWORD, IDataObject*, LONG*, LONG*,
+                                         TS_TEXTCHANGE*);
+
+ public: /*ITfContextOwnerCompositionSink*/
+  STDMETHODIMP OnStartComposition(ITfCompositionView*, BOOL*);
+  STDMETHODIMP OnUpdateComposition(ITfCompositionView*, ITfRange*);
+  STDMETHODIMP OnEndComposition(ITfCompositionView*);
+
+ public: /*ITfMouseTrackerACP*/
+  STDMETHODIMP AdviseMouseSink(ITfRangeACP*, ITfMouseSink*, DWORD*);
+  STDMETHODIMP UnadviseMouseSink(DWORD);
+
+ public:
+  static void Initialize(void);
+  static void Terminate(void);
+
+  static bool ProcessRawKeyMessage(const MSG& aMsg);
+  static void ProcessMessage(nsWindow* aWindow, UINT aMessage, WPARAM& aWParam,
+                             LPARAM& aLParam, MSGResult& aResult);
+
+  static void SetIMEOpenState(bool);
+  static bool GetIMEOpenState(void);
+
+  static void CommitComposition(bool aDiscard) {
+    NS_ASSERTION(IsInTSFMode(), "Not in TSF mode, shouldn't be called");
+    if (!sEnabledTextStore) {
+      return;
+    }
+    RefPtr<TSFTextStore> textStore(sEnabledTextStore);
+    textStore->CommitCompositionInternal(aDiscard);
+  }
+
+  static void SetInputContext(nsWindow* aWidget, const InputContext& aContext,
+                              const InputContextAction& aAction);
+
+  static nsresult OnFocusChange(bool aGotFocus, nsWindow* aFocusedWidget,
+                                const InputContext& aContext);
+  static nsresult OnTextChange(const IMENotification& aIMENotification) {
+    NS_ASSERTION(IsInTSFMode(), "Not in TSF mode, shouldn't be called");
+    if (!sEnabledTextStore) {
+      return NS_OK;
+    }
+    RefPtr<TSFTextStore> textStore(sEnabledTextStore);
+    return textStore->OnTextChangeInternal(aIMENotification);
+  }
+
+  static nsresult OnSelectionChange(const IMENotification& aIMENotification) {
+    NS_ASSERTION(IsInTSFMode(), "Not in TSF mode, shouldn't be called");
+    if (!sEnabledTextStore) {
+      return NS_OK;
+    }
+    RefPtr<TSFTextStore> textStore(sEnabledTextStore);
+    return textStore->OnSelectionChangeInternal(aIMENotification);
+  }
+
+  static nsresult OnLayoutChange() {
+    NS_ASSERTION(IsInTSFMode(), "Not in TSF mode, shouldn't be called");
+    if (!sEnabledTextStore) {
+      return NS_OK;
+    }
+    RefPtr<TSFTextStore> textStore(sEnabledTextStore);
+    return textStore->OnLayoutChangeInternal();
+  }
+
+  static nsresult OnUpdateComposition() {
+    NS_ASSERTION(IsInTSFMode(), "Not in TSF mode, shouldn't be called");
+    if (!sEnabledTextStore) {
+      return NS_OK;
+    }
+    RefPtr<TSFTextStore> textStore(sEnabledTextStore);
+    return textStore->OnUpdateCompositionInternal();
+  }
+
+  static nsresult OnMouseButtonEvent(const IMENotification& aIMENotification) {
+    NS_ASSERTION(IsInTSFMode(), "Not in TSF mode, shouldn't be called");
+    if (!sEnabledTextStore) {
+      return NS_OK;
+    }
+    RefPtr<TSFTextStore> textStore(sEnabledTextStore);
+    return textStore->OnMouseButtonEventInternal(aIMENotification);
+  }
+
+  static IMENotificationRequests GetIMENotificationRequests();
+
+  // Returns the address of the pointer so that the TSF automatic test can
+  // replace the system object with a custom implementation for testing.
+  // XXX TSF doesn't work now.  Should we remove it?
+  static void* GetNativeData(uint32_t aDataType) {
+    switch (aDataType) {
+      case NS_NATIVE_TSF_THREAD_MGR:
+        Initialize();  // Apply any previous changes
+        return static_cast<void*>(&sThreadMgr);
+      case NS_NATIVE_TSF_CATEGORY_MGR:
+        return static_cast<void*>(&sCategoryMgr);
+      case NS_NATIVE_TSF_DISPLAY_ATTR_MGR:
+        return static_cast<void*>(&sDisplayAttrMgr);
+      default:
+        return nullptr;
+    }
+  }
+
+  static void* GetThreadManager() { return static_cast<void*>(sThreadMgr); }
+
+  static bool ThinksHavingFocus() {
+    return (sEnabledTextStore && sEnabledTextStore->mContext);
+  }
+
+  static bool IsInTSFMode() { return sThreadMgr != nullptr; }
+
+  static bool IsComposing() {
+    return (sEnabledTextStore && sEnabledTextStore->mComposition.isSome());
+  }
+
+  static bool IsComposingOn(nsWindow* aWidget) {
+    return (IsComposing() && sEnabledTextStore->mWidget == aWidget);
+  }
+
+  static nsWindow* GetEnabledWindowBase() {
+    return sEnabledTextStore ? sEnabledTextStore->mWidget.get() : nullptr;
+  }
+
+  /**
+   * Returns true if active keyboard layout is a legacy IMM-IME.
+   */
+  static bool IsIMM_IMEActive();
+
+  /**
+   * Returns true if active TIP is MS-IME for Japanese.
+   */
+  static bool IsMSJapaneseIMEActive();
+
+  /**
+   * Returns true if active TIP is Google Japanese Input.
+   * Note that if Google Japanese Input is installed as an IMM-IME,
+   * this return false even if Google Japanese Input is active.
+   * So, you may need to check IMMHandler::IsGoogleJapaneseInputActive() too.
+   */
+  static bool IsGoogleJapaneseInputActive();
+
+  /**
+   * Returns true if active TIP is ATOK.
+   */
+  static bool IsATOKActive();
+
+  /**
+   * Returns true if active TIP or IME is a black listed one and we should
+   * set input scope of URL bar to IS_DEFAULT rather than IS_URL.
+   */
+  static bool ShouldSetInputScopeOfURLBarToDefault();
+
+  /**
+   * Returns true if TSF may crash if GetSelection() returns E_FAIL.
+   */
+  static bool DoNotReturnErrorFromGetSelection();
+
+#ifdef DEBUG
+  // Returns true when keyboard layout has IME (TIP).
+  static bool CurrentKeyboardLayoutHasIME();
+#endif  // #ifdef DEBUG
+
+ protected:
+  TSFTextStore();
+  ~TSFTextStore();
+
+  static bool CreateAndSetFocus(nsWindow* aFocusedWidget,
+                                const InputContext& aContext);
+  static void EnsureToDestroyAndReleaseEnabledTextStoreIf(
+      RefPtr<TSFTextStore>& aTextStore);
+  static void MarkContextAsKeyboardDisabled(ITfContext* aContext);
+  static void MarkContextAsEmpty(ITfContext* aContext);
+
+  bool Init(nsWindow* aWidget, const InputContext& aContext);
+  void Destroy();
+  void ReleaseTSFObjects();
+
+  bool IsReadLock(DWORD aLock) const {
+    return (TS_LF_READ == (aLock & TS_LF_READ));
+  }
+  bool IsReadWriteLock(DWORD aLock) const {
+    return (TS_LF_READWRITE == (aLock & TS_LF_READWRITE));
+  }
+  bool IsReadLocked() const { return IsReadLock(mLock); }
+  bool IsReadWriteLocked() const { return IsReadWriteLock(mLock); }
+
+  // This is called immediately after a call of OnLockGranted() of mSink.
+  // Note that mLock isn't cleared yet when this is called.
+  void DidLockGranted();
+
+  bool GetScreenExtInternal(RECT& aScreenExt);
+  // If aDispatchCompositionChangeEvent is true, this method will dispatch
+  // compositionchange event if this is called during IME composing.
+  // aDispatchCompositionChangeEvent should be true only when this is called
+  // from SetSelection.  Because otherwise, the compositionchange event should
+  // not be sent from here.
+  HRESULT SetSelectionInternal(const TS_SELECTION_ACP*,
+                               bool aDispatchCompositionChangeEvent = false);
+  bool InsertTextAtSelectionInternal(const nsAString& aInsertStr,
+                                     TS_TEXTCHANGE* aTextChange);
+  void CommitCompositionInternal(bool);
+  HRESULT GetDisplayAttribute(ITfProperty* aProperty, ITfRange* aRange,
+                              TF_DISPLAYATTRIBUTE* aResult);
+  HRESULT RestartCompositionIfNecessary(ITfRange* pRangeNew = nullptr);
+  class Composition;
+  HRESULT RestartComposition(Composition& aCurrentComposition,
+                             ITfCompositionView* aCompositionView,
+                             ITfRange* aNewRange);
+
+  // Following methods record composing action(s) to mPendingActions.
+  // They will be flushed FlushPendingActions().
+  HRESULT RecordCompositionStartAction(ITfCompositionView* aCompositionView,
+                                       ITfRange* aRange,
+                                       bool aPreserveSelection);
+  HRESULT RecordCompositionStartAction(ITfCompositionView* aCompositionView,
+                                       LONG aStart, LONG aLength,
+                                       bool aPreserveSelection);
+  HRESULT RecordCompositionUpdateAction();
+  HRESULT RecordCompositionEndAction();
+
+  // DispatchEvent() dispatches the event and if it may not be handled
+  // synchronously, this makes the instance not notify TSF of pending
+  // notifications until next notification from content.
+  void DispatchEvent(WidgetGUIEvent& aEvent);
+  void OnLayoutInformationAvaliable();
+
+  // FlushPendingActions() performs pending actions recorded in mPendingActions
+  // and clear it.
+  void FlushPendingActions();
+  // MaybeFlushPendingNotifications() performs pending notifications to TSF.
+  void MaybeFlushPendingNotifications();
+
+  nsresult OnTextChangeInternal(const IMENotification& aIMENotification);
+  nsresult OnSelectionChangeInternal(const IMENotification& aIMENotification);
+  nsresult OnMouseButtonEventInternal(const IMENotification& aIMENotification);
+  nsresult OnLayoutChangeInternal();
+  nsresult OnUpdateCompositionInternal();
+
+  // mPendingSelectionChangeData stores selection change data until notifying
+  // TSF of selection change.  If two or more selection changes occur, this
+  // stores the latest selection change data because only it is necessary.
+  Maybe<SelectionChangeData> mPendingSelectionChangeData;
+
+  // mPendingTextChangeData stores one or more text change data until notifying
+  // TSF of text change.  If two or more text changes occur, this merges
+  // every text change data.
+  TextChangeData mPendingTextChangeData;
+
+  void NotifyTSFOfTextChange();
+  void NotifyTSFOfSelectionChange();
+  bool NotifyTSFOfLayoutChange();
+  void NotifyTSFOfLayoutChangeAgain();
+
+  HRESULT HandleRequestAttrs(DWORD aFlags, ULONG aFilterCount,
+                             const TS_ATTRID* aFilterAttrs);
+  void SetInputScope(const nsString& aHTMLInputType,
+                     const nsString& aHTMLInputMode);
+
+  // Creates native caret over our caret.  This method only works on desktop
+  // application.  Otherwise, this does nothing.
+  void CreateNativeCaret();
+  // Destroys native caret if there is.
+  void MaybeDestroyNativeCaret();
+
+  /**
+   * MaybeHackNoErrorLayoutBugs() is a helper method of GetTextExt().  In
+   * strictly speaking, TSF is aware of asynchronous layout computation like us.
+   * However, Windows 10 version 1803 and older (including Windows 8.1 and
+   * older) Windows has a bug which is that the caller of GetTextExt() of TSF
+   * does not return TS_E_NOLAYOUT to TIP as is.  Additionally, even after
+   * fixing this bug, some TIPs are not work well when we return TS_E_NOLAYOUT.
+   * For avoiding this issue, this method checks current Windows version and
+   * active TIP, and if in case we cannot return TS_E_NOLAYOUT, this modifies
+   * aACPStart and aACPEnd to making sure that they are in range of unmodified
+   * characters.
+   *
+   * @param aACPStart   Initial value should be acpStart of GetTextExt().
+   *                    If this method returns true, this may be modified
+   *                    to be in range of unmodified characters.
+   * @param aACPEnd     Initial value should be acpEnd of GetTextExt().
+   *                    If this method returns true, this may be modified
+   *                    to be in range of unmodified characters.
+   *                    And also this may become same as aACPStart.
+   * @return            true if the caller shouldn't return TS_E_NOLAYOUT.
+   *                    In this case, this method modifies aACPStart and/or
+   *                    aASCPEnd to compute rectangle of unmodified characters.
+   *                    false if the caller can return TS_E_NOLAYOUT or
+   *                    we cannot have proper unmodified characters.
+   */
+  bool MaybeHackNoErrorLayoutBugs(LONG& aACPStart, LONG& aACPEnd);
+
+  // Holds the pointer to our current win32 widget
+  RefPtr<nsWindow> mWidget;
+  // mDispatcher is a helper class to dispatch composition events.
+  RefPtr<TextEventDispatcher> mDispatcher;
+  // Document manager for the currently focused editor
+  RefPtr<ITfDocumentMgr> mDocumentMgr;
+  // Edit cookie associated with the current editing context
+  DWORD mEditCookie;
+  // Editing context at the bottom of mDocumentMgr's context stack
+  RefPtr<ITfContext> mContext;
+  // Currently installed notification sink
+  RefPtr<ITextStoreACPSink> mSink;
+  // TS_AS_* mask of what events to notify
+  DWORD mSinkMask;
+  // 0 if not locked, otherwise TS_LF_* indicating the current lock
+  DWORD mLock;
+  // 0 if no lock is queued, otherwise TS_LF_* indicating the queue lock
+  DWORD mLockQueued;
+
+  uint32_t mHandlingKeyMessage;
+  void OnStartToHandleKeyMessage() {
+    // If we're starting to handle another key message during handling a
+    // key message, let's assume that the handling key message is handled by
+    // TIP and it sends another key message for hacking something.
+    // Let's try to dispatch a keyboard event now.
+    // FYI: All callers of this method grab this instance with local variable.
+    //      So, even after calling MaybeDispatchKeyboardEventAsProcessedByIME(),
+    //      we're safe to access any members.
+    if (!mDestroyed && sHandlingKeyMsg && !sIsKeyboardEventDispatched) {
+      MaybeDispatchKeyboardEventAsProcessedByIME();
+    }
+    ++mHandlingKeyMessage;
+  }
+  void OnEndHandlingKeyMessage(bool aIsProcessedByTSF) {
+    // If sHandlingKeyMsg has been handled by TSF or TIP and we're still
+    // alive, but we haven't dispatch keyboard event for it, let's fire it now.
+    // FYI: All callers of this method grab this instance with local variable.
+    //      So, even after calling MaybeDispatchKeyboardEventAsProcessedByIME(),
+    //      we're safe to access any members.
+    if (!mDestroyed && sHandlingKeyMsg && aIsProcessedByTSF &&
+        !sIsKeyboardEventDispatched) {
+      MaybeDispatchKeyboardEventAsProcessedByIME();
+    }
+    MOZ_ASSERT(mHandlingKeyMessage);
+    if (--mHandlingKeyMessage) {
+      return;
+    }
+    // If TSFTextStore instance is destroyed during handling key message(s),
+    // release all TSF objects when all nested key messages have been handled.
+    if (mDestroyed) {
+      ReleaseTSFObjects();
+    }
+  }
+
+  /**
+   * MaybeDispatchKeyboardEventAsProcessedByIME() tries to dispatch eKeyDown
+   * event or eKeyUp event for sHandlingKeyMsg and marking the dispatching
+   * event as "processed by IME".  Note that if the document is locked, this
+   * just adds a pending action into the queue and sets
+   * sIsKeyboardEventDispatched to true.
+   */
+  void MaybeDispatchKeyboardEventAsProcessedByIME();
+
+  /**
+   * DispatchKeyboardEventAsProcessedByIME() dispatches an eKeyDown or
+   * eKeyUp event with NativeKey class and aMsg.
+   */
+  void DispatchKeyboardEventAsProcessedByIME(const MSG& aMsg);
+
+  // Composition class stores a copy of the active composition string.  Only
+  // the data is updated during an InsertTextAtSelection call if we have a
+  // composition.  The data acts as a buffer until OnUpdateComposition is
+  // called and the data is flushed to editor through eCompositionChange.
+  // This allows all changes to be updated in batches to avoid inconsistencies
+  // and artifacts.
+  class Composition final : public OffsetAndData<LONG> {
+   public:
+    explicit Composition(ITfCompositionView* aCompositionView,
+                         LONG aCompositionStartOffset,
+                         const nsAString& aCompositionString)
+        : OffsetAndData<LONG>(aCompositionStartOffset, aCompositionString),
+          mView(aCompositionView) {}
+
+    ITfCompositionView* GetView() const { return mView; }
+
+    friend std::ostream& operator<<(std::ostream& aStream,
+                                    const Composition& aComposition) {
+      aStream << "{ mView=0x" << aComposition.mView.get()
+              << ", OffsetAndData<LONG>="
+              << static_cast<const OffsetAndData<LONG>&>(aComposition) << " }";
+      return aStream;
+    }
+
+   private:
+    RefPtr<ITfCompositionView> const mView;
+  };
+  // While the document is locked, we cannot dispatch any events which cause
+  // DOM events since the DOM events' handlers may modify the locked document.
+  // However, even while the document is locked, TSF may queries us.
+  // For that, TSFTextStore modifies mComposition even while the document is
+  // locked.  With mComposition, query methods can returns the text content
+  // information.
+  Maybe<Composition> mComposition;
+
+  /**
+   * IsHandlingCompositionInParent() returns true if eCompositionStart is
+   * dispatched, but eCompositionCommit(AsIs) is not dispatched.  This means
+   * that if composition is handled in a content process, this status indicates
+   * whether ContentCacheInParent has composition or not.  On the other hand,
+   * if it's handled in the chrome process, this is exactly same as
+   * IsHandlingCompositionInContent().
+   */
+  bool IsHandlingCompositionInParent() const {
+    return mDispatcher && mDispatcher->IsComposing();
+  }
+
+  /**
+   * IsHandlingCompositionInContent() returns true if there is a composition in
+   * the focused editor which may be in a content process.
+   */
+  bool IsHandlingCompositionInContent() const {
+    return mDispatcher && mDispatcher->IsHandlingComposition();
+  }
+
+  class Selection {
+   public:
+    static TS_SELECTION_ACP EmptyACP() {
+      return TS_SELECTION_ACP{
+          .acpStart = 0,
+          .acpEnd = 0,
+          .style = {.ase = TS_AE_NONE, .fInterimChar = FALSE}};
+    }
+
+    bool HasRange() const { return mACP.isSome(); }
+    const TS_SELECTION_ACP& ACPRef() const { return mACP.ref(); }
+
+    explicit Selection(const TS_SELECTION_ACP& aSelection) {
+      SetSelection(aSelection);
+    }
+
+    explicit Selection(uint32_t aOffsetToCollapse) {
+      Collapse(aOffsetToCollapse);
+    }
+
+    explicit Selection(const SelectionChangeDataBase& aSelectionChangeData) {
+      SetSelection(aSelectionChangeData);
+    }
+
+    explicit Selection(const WidgetQueryContentEvent& aQuerySelectionEvent) {
+      SetSelection(aQuerySelectionEvent);
+    }
+
+    Selection(uint32_t aStart, uint32_t aLength, bool aReversed,
+              const WritingMode& aWritingMode) {
+      SetSelection(aStart, aLength, aReversed, aWritingMode);
+    }
+
+    void SetSelection(const TS_SELECTION_ACP& aSelection) {
+      mACP = Some(aSelection);
+      // Selection end must be active in our editor.
+      if (mACP->style.ase != TS_AE_START) {
+        mACP->style.ase = TS_AE_END;
+      }
+      // We're not support interim char selection for now.
+      // XXX Probably, this is necessary for supporting South Asian languages.
+      mACP->style.fInterimChar = FALSE;
+    }
+
+    bool SetSelection(const SelectionChangeDataBase& aSelectionChangeData) {
+      MOZ_ASSERT(aSelectionChangeData.IsInitialized());
+      if (!aSelectionChangeData.HasRange()) {
+        if (mACP.isNothing()) {
+          return false;
+        }
+        mACP.reset();
+        // Let's keep the WritingMode because users don't want to change the UI
+        // of TIP temporarily since no selection case is created only by web
+        // apps, but they or TIP would restore selection at last point later.
+        return true;
+      }
+      return SetSelection(aSelectionChangeData.mOffset,
+                          aSelectionChangeData.Length(),
+                          aSelectionChangeData.mReversed,
+                          aSelectionChangeData.GetWritingMode());
+    }
+
+    bool SetSelection(const WidgetQueryContentEvent& aQuerySelectionEvent) {
+      MOZ_ASSERT(aQuerySelectionEvent.mMessage == eQuerySelectedText);
+      MOZ_ASSERT(aQuerySelectionEvent.Succeeded());
+      if (aQuerySelectionEvent.DidNotFindSelection()) {
+        if (mACP.isNothing()) {
+          return false;
+        }
+        mACP.reset();
+        // Let's keep the WritingMode because users don't want to change the UI
+        // of TIP temporarily since no selection case is created only by web
+        // apps, but they or TIP would restore selection at last point later.
+        return true;
+      }
+      return SetSelection(aQuerySelectionEvent.mReply->StartOffset(),
+                          aQuerySelectionEvent.mReply->DataLength(),
+                          aQuerySelectionEvent.mReply->mReversed,
+                          aQuerySelectionEvent.mReply->WritingModeRef());
+    }
+
+    bool SetSelection(uint32_t aStart, uint32_t aLength, bool aReversed,
+                      const WritingMode& aWritingMode) {
+      const bool changed = mACP.isNothing() ||
+                           mACP->acpStart != static_cast<LONG>(aStart) ||
+                           mACP->acpEnd != static_cast<LONG>(aStart + aLength);
+      mACP = Some(
+          TS_SELECTION_ACP{.acpStart = static_cast<LONG>(aStart),
+                           .acpEnd = static_cast<LONG>(aStart + aLength),
+                           .style = {.ase = aReversed ? TS_AE_START : TS_AE_END,
+                                     .fInterimChar = FALSE}});
+      mWritingMode = aWritingMode;
+
+      return changed;
+    }
+
+    bool Collapsed() const {
+      return mACP.isNothing() || mACP->acpStart == mACP->acpEnd;
+    }
+
+    void Collapse(uint32_t aOffset) {
+      // XXX This does not update the selection's mWritingMode.
+      // If it is ever used to "collapse" to an entirely new location,
+      // we may need to fix that.
+      mACP = Some(
+          TS_SELECTION_ACP{.acpStart = static_cast<LONG>(aOffset),
+                           .acpEnd = static_cast<LONG>(aOffset),
+                           .style = {.ase = TS_AE_END, .fInterimChar = FALSE}});
+    }
+
+    LONG MinOffset() const {
+      MOZ_ASSERT(mACP.isSome());
+      LONG min = std::min(mACP->acpStart, mACP->acpEnd);
+      MOZ_ASSERT(min >= 0);
+      return min;
+    }
+
+    LONG MaxOffset() const {
+      MOZ_ASSERT(mACP.isSome());
+      LONG max = std::max(mACP->acpStart, mACP->acpEnd);
+      MOZ_ASSERT(max >= 0);
+      return max;
+    }
+
+    LONG StartOffset() const {
+      MOZ_ASSERT(mACP.isSome());
+      MOZ_ASSERT(mACP->acpStart >= 0);
+      return mACP->acpStart;
+    }
+
+    LONG EndOffset() const {
+      MOZ_ASSERT(mACP.isSome());
+      MOZ_ASSERT(mACP->acpEnd >= 0);
+      return mACP->acpEnd;
+    }
+
+    LONG Length() const {
+      MOZ_ASSERT_IF(mACP.isSome(), mACP->acpEnd >= mACP->acpStart);
+      return mACP.isSome() ? std::abs(mACP->acpEnd - mACP->acpStart) : 0;
+    }
+
+    bool IsReversed() const {
+      return mACP.isSome() && mACP->style.ase == TS_AE_START;
+    }
+
+    TsActiveSelEnd ActiveSelEnd() const {
+      return mACP.isSome() ? mACP->style.ase : TS_AE_NONE;
+    }
+
+    bool IsInterimChar() const {
+      return mACP.isSome() && mACP->style.fInterimChar != FALSE;
+    }
+
+    const WritingMode& WritingModeRef() const { return mWritingMode; }
+
+    bool EqualsExceptDirection(const TS_SELECTION_ACP& aACP) const {
+      if (mACP.isNothing()) {
+        return false;
+      }
+      if (mACP->style.ase == aACP.style.ase) {
+        return mACP->acpStart == aACP.acpStart && mACP->acpEnd == aACP.acpEnd;
+      }
+      return mACP->acpStart == aACP.acpEnd && mACP->acpEnd == aACP.acpStart;
+    }
+
+    bool EqualsExceptDirection(
+        const SelectionChangeDataBase& aChangedSelection) const {
+      MOZ_ASSERT(aChangedSelection.IsInitialized());
+      if (mACP.isNothing()) {
+        return aChangedSelection.HasRange();
+      }
+      return aChangedSelection.Length() == static_cast<uint32_t>(Length()) &&
+             aChangedSelection.mOffset == static_cast<uint32_t>(StartOffset());
+    }
+
+    friend std::ostream& operator<<(std::ostream& aStream,
+                                    const Selection& aSelection) {
+      aStream << "{ mACP=" << ToString(aSelection.mACP).c_str()
+              << ", mWritingMode=" << ToString(aSelection.mWritingMode).c_str()
+              << ",  Collapsed()="
+              << (aSelection.Collapsed() ? "true" : "false")
+              << ", Length=" << aSelection.Length() << " }";
+      return aStream;
+    }
+
+   private:
+    Maybe<TS_SELECTION_ACP> mACP;  // If Nothing, there is no selection
+    WritingMode mWritingMode;
+  };
+  // Don't access mSelection directly.  Instead, Use SelectionForTSFRef().
+  // This is modified immediately when TSF requests to set selection and not
+  // updated by selection change in content until mContentForTSF is cleared.
+  Maybe<Selection> mSelectionForTSF;
+
+  /**
+   * Get the selection expected by TSF.  If mSelectionForTSF is already valid,
+   * this just return the reference to it.  Otherwise, this initializes it
+   * with eQuerySelectedText.  Please check if the result is valid before
+   * actually using it.
+   * Note that this is also called by ContentForTSF().
+   */
+  Maybe<Selection>& SelectionForTSF();
+
+  struct PendingAction final {
+    enum class Type : uint8_t {
+      eCompositionStart,
+      eCompositionUpdate,
+      eCompositionEnd,
+      eSetSelection,
+      eKeyboardEvent,
+    };
+    Type mType;
+    // For eCompositionStart, eCompositionEnd and eSetSelection
+    LONG mSelectionStart;
+    // For eCompositionStart and eSetSelection
+    LONG mSelectionLength;
+    // For eCompositionStart, eCompositionUpdate and eCompositionEnd
+    nsString mData;
+    // For eCompositionUpdate
+    RefPtr<TextRangeArray> mRanges;
+    // For eKeyboardEvent
+    MSG mKeyMsg;
+    // For eSetSelection
+    bool mSelectionReversed;
+    // For eCompositionUpdate
+    bool mIncomplete;
+    // For eCompositionStart
+    bool mAdjustSelection;
+  };
+  // Items of mPendingActions are appended when TSF tells us to need to dispatch
+  // DOM composition events.  However, we cannot dispatch while the document is
+  // locked because it can cause modifying the locked document.  So, the pending
+  // actions should be performed when document lock is unlocked.
+  nsTArray<PendingAction> mPendingActions;
+
+  PendingAction* LastOrNewPendingCompositionUpdate() {
+    if (!mPendingActions.IsEmpty()) {
+      PendingAction& lastAction = mPendingActions.LastElement();
+      if (lastAction.mType == PendingAction::Type::eCompositionUpdate) {
+        return &lastAction;
+      }
+    }
+    PendingAction* newAction = mPendingActions.AppendElement();
+    newAction->mType = PendingAction::Type::eCompositionUpdate;
+    newAction->mRanges = new TextRangeArray();
+    newAction->mIncomplete = true;
+    return newAction;
+  }
+
+  /**
+   * IsLastPendingActionCompositionEndAt() checks whether the previous pending
+   * action is committing composition whose range starts from aStart and its
+   * length is aLength.  In other words, this checks whether new composition
+   * which will replace same range as previous pending commit can be merged
+   * with the previous composition.
+   *
+   * @param aStart              The inserted offset you expected.
+   * @param aLength             The inserted text length you expected.
+   * @return                    true if the last pending action is
+   *                            eCompositionEnd and it inserted the text
+   *                            between aStart and aStart + aLength.
+   */
+  bool IsLastPendingActionCompositionEndAt(LONG aStart, LONG aLength) const {
+    if (mPendingActions.IsEmpty()) {
+      return false;
+    }
+    const PendingAction& pendingLastAction = mPendingActions.LastElement();
+    return pendingLastAction.mType == PendingAction::Type::eCompositionEnd &&
+           pendingLastAction.mSelectionStart == aStart &&
+           pendingLastAction.mData.Length() == static_cast<ULONG>(aLength);
+  }
+
+  bool IsPendingCompositionUpdateIncomplete() const {
+    if (mPendingActions.IsEmpty()) {
+      return false;
+    }
+    const PendingAction& lastAction = mPendingActions.LastElement();
+    return lastAction.mType == PendingAction::Type::eCompositionUpdate &&
+           lastAction.mIncomplete;
+  }
+
+  void CompleteLastActionIfStillIncomplete() {
+    if (!IsPendingCompositionUpdateIncomplete()) {
+      return;
+    }
+    RecordCompositionUpdateAction();
+  }
+
+  void RemoveLastCompositionUpdateActions() {
+    while (!mPendingActions.IsEmpty()) {
+      const PendingAction& lastAction = mPendingActions.LastElement();
+      if (lastAction.mType != PendingAction::Type::eCompositionUpdate) {
+        break;
+      }
+      mPendingActions.RemoveLastElement();
+    }
+  }
+
+  // When On*Composition() is called without document lock, we need to flush
+  // the recorded actions at quitting the method.
+  // AutoPendingActionAndContentFlusher class is usedful for it.
+  class MOZ_STACK_CLASS AutoPendingActionAndContentFlusher final {
+   public:
+    explicit AutoPendingActionAndContentFlusher(TSFTextStore* aTextStore)
+        : mTextStore(aTextStore) {
+      MOZ_ASSERT(!mTextStore->mIsRecordingActionsWithoutLock);
+      if (!mTextStore->IsReadWriteLocked()) {
+        mTextStore->mIsRecordingActionsWithoutLock = true;
+      }
+    }
+
+    ~AutoPendingActionAndContentFlusher() {
+      if (!mTextStore->mIsRecordingActionsWithoutLock) {
+        return;
+      }
+      mTextStore->FlushPendingActions();
+      mTextStore->mIsRecordingActionsWithoutLock = false;
+    }
+
+   private:
+    AutoPendingActionAndContentFlusher() {}
+
+    RefPtr<TSFTextStore> mTextStore;
+  };
+
+  class Content final {
+   public:
+    Content(TSFTextStore& aTSFTextStore, const nsAString& aText)
+        : mText(aText),
+          mLastComposition(aTSFTextStore.mComposition),
+          mComposition(aTSFTextStore.mComposition),
+          mSelection(aTSFTextStore.mSelectionForTSF) {}
+
+    void OnLayoutChanged() { mMinModifiedOffset.reset(); }
+
+    // OnCompositionEventsHandled() is called when all pending composition
+    // events are handled in the focused content which may be in a remote
+    // process.
+    void OnCompositionEventsHandled() { mLastComposition = mComposition; }
+
+    const nsDependentSubstring GetSelectedText() const;
+    const nsDependentSubstring GetSubstring(uint32_t aStart,
+                                            uint32_t aLength) const;
+    void ReplaceSelectedTextWith(const nsAString& aString);
+    void ReplaceTextWith(LONG aStart, LONG aLength, const nsAString& aString);
+
+    void StartComposition(ITfCompositionView* aCompositionView,
+                          const PendingAction& aCompStart,
+                          bool aPreserveSelection);
+    /**
+     * RestoreCommittedComposition() restores the committed string as
+     * composing string.  If InsertTextAtSelection() or something is called
+     * before a call of OnStartComposition() or previous composition is
+     * committed and new composition is restarted to clean up the commited
+     * string, there is a pending compositionend.  In this case, we need to
+     * cancel the pending compositionend and continue the composition.
+     *
+     * @param aCompositionView          The composition view.
+     * @param aCanceledCompositionEnd   The pending compositionend which is
+     *                                  canceled for restarting the composition.
+     */
+    void RestoreCommittedComposition(
+        ITfCompositionView* aCompositionView,
+        const PendingAction& aCanceledCompositionEnd);
+    void EndComposition(const PendingAction& aCompEnd);
+
+    const nsString& TextRef() const { return mText; }
+    const Maybe<OffsetAndData<LONG>>& LastComposition() const {
+      return mLastComposition;
+    }
+    const Maybe<uint32_t>& MinModifiedOffset() const {
+      return mMinModifiedOffset;
+    }
+    const Maybe<StartAndEndOffsets<LONG>>& LatestCompositionRange() const {
+      return mLatestCompositionRange;
+    }
+
+    // Returns true if layout of the character at the aOffset has not been
+    // calculated.
+    bool IsLayoutChangedAt(uint32_t aOffset) const {
+      return IsLayoutChanged() && (mMinModifiedOffset.value() <= aOffset);
+    }
+    // Returns true if layout of the content has been changed, i.e., the new
+    // layout has not been calculated.
+    bool IsLayoutChanged() const { return mMinModifiedOffset.isSome(); }
+    bool HasOrHadComposition() const {
+      return mLatestCompositionRange.isSome();
+    }
+
+    Maybe<TSFTextStore::Composition>& Composition() { return mComposition; }
+    Maybe<TSFTextStore::Selection>& Selection() { return mSelection; }
+
+    friend std::ostream& operator<<(std::ostream& aStream,
+                                    const Content& aContent) {
+      aStream << "{ mText="
+              << PrintStringDetail(aContent.mText,
+                                   PrintStringDetail::kMaxLengthForEditor)
+                     .get()
+              << ", mLastComposition=" << aContent.mLastComposition
+              << ", mLatestCompositionRange="
+              << aContent.mLatestCompositionRange
+              << ", mMinModifiedOffset=" << aContent.mMinModifiedOffset << " }";
+      return aStream;
+    }
+
+   private:
+    nsString mText;
+
+    // mLastComposition may store the composition string and its start offset
+    // when the document is locked. This is necessary to compute
+    // mMinTextModifiedOffset.
+    Maybe<OffsetAndData<LONG>> mLastComposition;
+
+    Maybe<TSFTextStore::Composition>& mComposition;
+    Maybe<TSFTextStore::Selection>& mSelection;
+
+    // The latest composition's start and end offset.
+    Maybe<StartAndEndOffsets<LONG>> mLatestCompositionRange;
+
+    // The minimum offset of modified part of the text.
+    Maybe<uint32_t> mMinModifiedOffset;
+  };
+  // mContentForTSF is cache of content.  The information is expected by TSF
+  // and TIP.  Therefore, this is useful for answering the query from TSF or
+  // TIP.
+  // This is initialized by ContentForTSF() automatically (therefore, don't
+  // access this member directly except at calling Clear(), IsInitialized(),
+  // IsLayoutChangeAfter() or IsLayoutChanged()).
+  // This is cleared when:
+  //  - When there is no composition, the document is unlocked.
+  //  - When there is a composition, all dispatched events are handled by
+  //    the focused editor which may be in a remote process.
+  // So, if two compositions are created very quickly, this cache may not be
+  // cleared between eCompositionCommit(AsIs) and eCompositionStart.
+  Maybe<Content> mContentForTSF;
+
+  Maybe<Content>& ContentForTSF();
+
+  class MOZ_STACK_CLASS AutoNotifyingTSFBatch final {
+   public:
+    explicit AutoNotifyingTSFBatch(TSFTextStore& aTextStore)
+        : mTextStore(aTextStore), mOldValue(aTextStore.mDeferNotifyingTSF) {
+      mTextStore.mDeferNotifyingTSF = true;
+    }
+    ~AutoNotifyingTSFBatch() {
+      mTextStore.mDeferNotifyingTSF = mOldValue;
+      mTextStore.MaybeFlushPendingNotifications();
+    }
+
+   private:
+    TSFTextStore& mTextStore;
+    bool mOldValue;
+  };
+
+  // CanAccessActualContentDirectly() returns true when TSF/TIP can access
+  // actual content directly.  In other words, mContentForTSF and/or
+  // mSelectionForTSF doesn't cache content or they matches with actual
+  // contents due to no pending text/selection change notifications.
+  bool CanAccessActualContentDirectly() const;
+
+  // While mContentForTSF is valid, this returns the text stored by it.
+  // Otherwise, return the current text content retrieved by eQueryTextContent.
+  bool GetCurrentText(nsAString& aTextContent);
+
+  class MouseTracker final {
+   public:
+    static const DWORD kInvalidCookie = static_cast<DWORD>(-1);
+
+    MouseTracker();
+
+    HRESULT Init(TSFTextStore* aTextStore);
+    HRESULT AdviseSink(TSFTextStore* aTextStore, ITfRangeACP* aTextRange,
+                       ITfMouseSink* aMouseSink);
+    void UnadviseSink();
+
+    bool IsUsing() const { return mSink != nullptr; }
+    DWORD Cookie() const { return mCookie; }
+    bool OnMouseButtonEvent(ULONG aEdge, ULONG aQuadrant, DWORD aButtonStatus);
+    const Maybe<StartAndEndOffsets<LONG>> Range() const { return mRange; }
+
+   private:
+    RefPtr<ITfMouseSink> mSink;
+    Maybe<StartAndEndOffsets<LONG>> mRange;
+    DWORD mCookie;
+  };
+  // mMouseTrackers is an array to store each information of installed
+  // ITfMouseSink instance.
+  nsTArray<MouseTracker> mMouseTrackers;
+
+  // The input scopes for this context, defaults to IS_DEFAULT.
+  nsTArray<InputScope> mInputScopes;
+
+  // The URL cache of the focused document.
+  nsString mDocumentURL;
+
+  // Support retrieving attributes.
+  // TODO: We should support RightToLeft, perhaps.
+  enum {
+    // Used for result of GetRequestedAttrIndex()
+    eNotSupported = -1,
+
+    // Supported attributes
+    eInputScope = 0,
+    eDocumentURL,
+    eTextVerticalWriting,
+    eTextOrientation,
+
+    // Count of the supported attributes
+    NUM_OF_SUPPORTED_ATTRS
+  };
+  bool mRequestedAttrs[NUM_OF_SUPPORTED_ATTRS] = {false};
+
+  int32_t GetRequestedAttrIndex(const TS_ATTRID& aAttrID);
+  TS_ATTRID GetAttrID(int32_t aIndex);
+
+  bool mRequestedAttrValues = false;
+
+  // If edit actions are being recorded without document lock, this is true.
+  // Otherwise, false.
+  bool mIsRecordingActionsWithoutLock = false;
+  // If GetTextExt() or GetACPFromPoint() is called and the layout hasn't been
+  // calculated yet, these methods return TS_E_NOLAYOUT.  At that time,
+  // mHasReturnedNoLayoutError is set to true.
+  bool mHasReturnedNoLayoutError = false;
+  // Before calling ITextStoreACPSink::OnLayoutChange() and
+  // ITfContextOwnerServices::OnLayoutChange(), mWaitingQueryLayout is set to
+  // true.  This is set to  false when GetTextExt() or GetACPFromPoint() is
+  // called.
+  bool mWaitingQueryLayout = false;
+  // During the document is locked, we shouldn't destroy the instance.
+  // If this is true, the instance will be destroyed after unlocked.
+  bool mPendingDestroy = false;
+  // If this is false, MaybeFlushPendingNotifications() will clear the
+  // mContentForTSF.
+  bool mDeferClearingContentForTSF = false;
+  // While the instance is initializing content/selection cache, another
+  // initialization shouldn't run recursively.  Therefore, while the
+  // initialization is running, this is set to true.  Use AutoNotifyingTSFBatch
+  // to set this.
+  bool mDeferNotifyingTSF = false;
+  // While the instance is dispatching events, the event may not be handled
+  // synchronously when remote content has focus.  In the case, we cannot
+  // return the latest layout/content information to TSF/TIP until we get next
+  // update notification from ContentCacheInParent.  For preventing TSF/TIP
+  // retrieves the latest content/layout information while it becomes available,
+  // we should put off notifying TSF of any updates.
+  bool mDeferNotifyingTSFUntilNextUpdate = false;
+  // While the document is locked, committing composition always fails since
+  // TSF needs another document lock for modifying the composition, selection
+  // and etc.  So, committing composition should be performed after the
+  // document is unlocked.
+  bool mDeferCommittingComposition = false;
+  bool mDeferCancellingComposition = false;
+  // Immediately after a call of Destroy(), mDestroyed becomes true.  If this
+  // is true, the instance shouldn't grant any requests from the TIP anymore.
+  bool mDestroyed = false;
+  // While the instance is being destroyed, this is set to true for avoiding
+  // recursive Destroy() calls.
+  bool mBeingDestroyed = false;
+  // Whether we're in the private browsing mode.
+  bool mInPrivateBrowsing = true;
+  // Debug flag to check whether we're initializing mContentForTSF and
+  // mSelectionForTSF.
+  bool mIsInitializingContentForTSF = false;
+  bool mIsInitializingSelectionForTSF = false;
+
+  // TSF thread manager object for the current application
+  static StaticRefPtr<ITfThreadMgr> sThreadMgr;
+  static already_AddRefed<ITfThreadMgr> GetThreadMgr();
+  // sMessagePump is QI'ed from sThreadMgr
+  static StaticRefPtr<ITfMessagePump> sMessagePump;
+
+ public:
+  // Expose GetMessagePump() for WinUtils.
+  static already_AddRefed<ITfMessagePump> GetMessagePump();
+
+ private:
+  // sKeystrokeMgr is QI'ed from sThreadMgr
+  static StaticRefPtr<ITfKeystrokeMgr> sKeystrokeMgr;
+  // TSF display attribute manager
+  static StaticRefPtr<ITfDisplayAttributeMgr> sDisplayAttrMgr;
+  static already_AddRefed<ITfDisplayAttributeMgr> GetDisplayAttributeMgr();
+  // TSF category manager
+  static StaticRefPtr<ITfCategoryMgr> sCategoryMgr;
+  static already_AddRefed<ITfCategoryMgr> GetCategoryMgr();
+  // Compartment for (Get|Set)IMEOpenState()
+  static StaticRefPtr<ITfCompartment> sCompartmentForOpenClose;
+  static already_AddRefed<ITfCompartment> GetCompartmentForOpenClose();
+
+  // Current text store which is managing a keyboard enabled editor (i.e.,
+  // editable editor).  Currently only ONE TSFTextStore instance is ever used,
+  // although Create is called when an editor is focused and Destroy called
+  // when the focused editor is blurred.
+  static StaticRefPtr<TSFTextStore> sEnabledTextStore;
+
+  // For IME (keyboard) disabled state:
+  static StaticRefPtr<ITfDocumentMgr> sDisabledDocumentMgr;
+  static StaticRefPtr<ITfContext> sDisabledContext;
+
+  static StaticRefPtr<ITfInputProcessorProfiles> sInputProcessorProfiles;
+  static already_AddRefed<ITfInputProcessorProfiles>
+  GetInputProcessorProfiles();
+
+  // Handling key message.
+  static const MSG* sHandlingKeyMsg;
+
+  // TSF client ID for the current application
+  static DWORD sClientId;
+
+  // true if an eKeyDown or eKeyUp event for sHandlingKeyMsg has already
+  // been dispatched.
+  static bool sIsKeyboardEventDispatched;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // #ifndef TSFTextStore_h_
diff --git a/widget/windows/TaskbarPreview.cpp b/widget/windows/TaskbarPreview.cpp
new file mode 100644
index 0000000000..2b958f84c1
--- /dev/null
+++ b/widget/windows/TaskbarPreview.cpp
@@ -0,0 +1,413 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TaskbarPreview.h"
+#include <nsITaskbarPreviewController.h>
+#include <windows.h>
+
+#include <nsError.h>
+#include <nsCOMPtr.h>
+#include <nsIWidget.h>
+#include <nsServiceManagerUtils.h>
+
+#include "nsUXThemeData.h"
+#include "nsWindow.h"
+#include "nsAppShell.h"
+#include "TaskbarPreviewButton.h"
+#include "WinUtils.h"
+
+#include "mozilla/dom/HTMLCanvasElement.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/DataSurfaceHelpers.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/Telemetry.h"
+
+// Defined in dwmapi in a header that needs a higher numbered _WINNT #define
+#ifndef DWM_SIT_DISPLAYFRAME
+#  define DWM_SIT_DISPLAYFRAME 0x1
+#endif
+
+namespace mozilla {
+namespace widget {
+
+///////////////////////////////////////////////////////////////////////////////
+// TaskbarPreview
+
+TaskbarPreview::TaskbarPreview(ITaskbarList4* aTaskbar,
+                               nsITaskbarPreviewController* aController,
+                               HWND aHWND, nsIDocShell* aShell)
+    : mTaskbar(aTaskbar),
+      mController(aController),
+      mWnd(aHWND),
+      mVisible(false),
+      mDocShell(do_GetWeakReference(aShell)) {}
+
+TaskbarPreview::~TaskbarPreview() {
+  // Avoid dangling pointer
+  if (sActivePreview == this) sActivePreview = nullptr;
+
+  // Our subclass should have invoked DetachFromNSWindow already.
+  NS_ASSERTION(
+      !mWnd,
+      "TaskbarPreview::DetachFromNSWindow was not called before destruction");
+
+  // Make sure to release before potentially uninitializing COM
+  mTaskbar = nullptr;
+
+  ::CoUninitialize();
+}
+
+nsresult TaskbarPreview::Init() {
+  // TaskbarPreview may outlive the WinTaskbar that created it
+  if (FAILED(::CoInitialize(nullptr))) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+
+  WindowHook* hook = GetWindowHook();
+  if (!hook) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+  return hook->AddMonitor(WM_DESTROY, MainWindowHook, this);
+}
+
+NS_IMETHODIMP
+TaskbarPreview::SetController(nsITaskbarPreviewController* aController) {
+  NS_ENSURE_ARG(aController);
+
+  mController = aController;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreview::GetController(nsITaskbarPreviewController** aController) {
+  NS_ADDREF(*aController = mController);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreview::GetTooltip(nsAString& aTooltip) {
+  aTooltip = mTooltip;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreview::SetTooltip(const nsAString& aTooltip) {
+  mTooltip = aTooltip;
+  return CanMakeTaskbarCalls() ? UpdateTooltip() : NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreview::SetVisible(bool visible) {
+  if (mVisible == visible) return NS_OK;
+  mVisible = visible;
+
+  // If the nsWindow has already been destroyed but the caller is still trying
+  // to use it then just pretend that everything succeeded.  The caller doesn't
+  // actually have a way to detect this since it's the same case as when we
+  // CanMakeTaskbarCalls returns false.
+  if (!IsWindowAvailable()) return NS_OK;
+
+  return visible ? Enable() : Disable();
+}
+
+NS_IMETHODIMP
+TaskbarPreview::GetVisible(bool* visible) {
+  *visible = mVisible;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreview::SetActive(bool active) {
+  if (active)
+    sActivePreview = this;
+  else if (sActivePreview == this)
+    sActivePreview = nullptr;
+
+  return CanMakeTaskbarCalls() ? ShowActive(active) : NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreview::GetActive(bool* active) {
+  *active = sActivePreview == this;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreview::Invalidate() {
+  if (!mVisible) return NS_OK;
+
+  HWND previewWindow = PreviewWindow();
+  return FAILED(DwmInvalidateIconicBitmaps(previewWindow)) ? NS_ERROR_FAILURE
+                                                           : NS_OK;
+}
+
+nsresult TaskbarPreview::UpdateTaskbarProperties() {
+  nsresult rv = UpdateTooltip();
+
+  // If we are the active preview and our window is the active window, restore
+  // our active state - otherwise some other non-preview window is now active
+  // and should be displayed as so.
+  if (sActivePreview == this) {
+    if (mWnd == ::GetActiveWindow()) {
+      nsresult rvActive = ShowActive(true);
+      if (NS_FAILED(rvActive)) rv = rvActive;
+    } else {
+      sActivePreview = nullptr;
+    }
+  }
+  return rv;
+}
+
+nsresult TaskbarPreview::Enable() {
+  nsresult rv = NS_OK;
+  if (CanMakeTaskbarCalls()) {
+    rv = UpdateTaskbarProperties();
+  } else if (IsWindowAvailable()) {
+    WindowHook* hook = GetWindowHook();
+    MOZ_ASSERT(hook,
+               "IsWindowAvailable() should have eliminated the null case.");
+    hook->AddMonitor(nsAppShell::GetTaskbarButtonCreatedMessage(),
+                     MainWindowHook, this);
+  }
+  return rv;
+}
+
+nsresult TaskbarPreview::Disable() {
+  if (!IsWindowAvailable()) {
+    // Window is already destroyed
+    return NS_OK;
+  }
+
+  WindowHook* hook = GetWindowHook();
+  MOZ_ASSERT(hook, "IsWindowAvailable() should have eliminated the null case.");
+  (void)hook->RemoveMonitor(nsAppShell::GetTaskbarButtonCreatedMessage(),
+                            MainWindowHook, this);
+
+  return NS_OK;
+}
+
+bool TaskbarPreview::IsWindowAvailable() const {
+  if (mWnd) {
+    nsWindow* win = WinUtils::GetNSWindowPtr(mWnd);
+    if (win && !win->Destroyed()) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void TaskbarPreview::DetachFromNSWindow() {
+  if (WindowHook* hook = GetWindowHook()) {
+    hook->RemoveMonitor(WM_DESTROY, MainWindowHook, this);
+  }
+  mWnd = nullptr;
+}
+
+LRESULT
+TaskbarPreview::WndProc(UINT nMsg, WPARAM wParam, LPARAM lParam) {
+  switch (nMsg) {
+    case WM_DWMSENDICONICTHUMBNAIL: {
+      uint32_t width = HIWORD(lParam);
+      uint32_t height = LOWORD(lParam);
+      float aspectRatio = width / float(height);
+
+      nsresult rv;
+      float preferredAspectRatio;
+      rv = mController->GetThumbnailAspectRatio(&preferredAspectRatio);
+      if (NS_FAILED(rv)) break;
+
+      uint32_t thumbnailWidth = width;
+      uint32_t thumbnailHeight = height;
+
+      if (aspectRatio > preferredAspectRatio) {
+        thumbnailWidth = uint32_t(thumbnailHeight * preferredAspectRatio);
+      } else {
+        thumbnailHeight = uint32_t(thumbnailWidth / preferredAspectRatio);
+      }
+
+      DrawBitmap(thumbnailWidth, thumbnailHeight, false);
+    } break;
+    case WM_DWMSENDICONICLIVEPREVIEWBITMAP: {
+      uint32_t width, height;
+      nsresult rv;
+      rv = mController->GetWidth(&width);
+      if (NS_FAILED(rv)) break;
+      rv = mController->GetHeight(&height);
+      if (NS_FAILED(rv)) break;
+
+      double scale = StaticPrefs::layout_css_devPixelsPerPx();
+      if (scale <= 0.0) {
+        scale = WinUtils::LogToPhysFactor(PreviewWindow());
+      }
+      DrawBitmap(NSToIntRound(scale * width), NSToIntRound(scale * height),
+                 true);
+    } break;
+  }
+  return ::DefWindowProcW(PreviewWindow(), nMsg, wParam, lParam);
+}
+
+bool TaskbarPreview::CanMakeTaskbarCalls() {
+  // If the nsWindow has already been destroyed and we know it but our caller
+  // clearly doesn't so we can't make any calls.
+  if (!mWnd) return false;
+  // Certain functions like SetTabOrder seem to require a visible window. During
+  // window close, the window seems to be hidden before being destroyed.
+  if (!::IsWindowVisible(mWnd)) return false;
+  if (mVisible) {
+    nsWindow* window = WinUtils::GetNSWindowPtr(mWnd);
+    NS_ASSERTION(window, "Could not get nsWindow from HWND");
+    return window ? window->HasTaskbarIconBeenCreated() : false;
+  }
+  return false;
+}
+
+WindowHook* TaskbarPreview::GetWindowHook() {
+  nsWindow* window = WinUtils::GetNSWindowPtr(mWnd);
+  NS_ASSERTION(window, "Cannot use taskbar previews in an embedded context!");
+
+  return window ? &window->GetWindowHook() : nullptr;
+}
+
+void TaskbarPreview::EnableCustomDrawing(HWND aHWND, bool aEnable) {
+  BOOL enabled = aEnable;
+  DwmSetWindowAttribute(aHWND, DWMWA_FORCE_ICONIC_REPRESENTATION, &enabled,
+                        sizeof(enabled));
+
+  DwmSetWindowAttribute(aHWND, DWMWA_HAS_ICONIC_BITMAP, &enabled,
+                        sizeof(enabled));
+}
+
+nsresult TaskbarPreview::UpdateTooltip() {
+  NS_ASSERTION(CanMakeTaskbarCalls() && mVisible,
+               "UpdateTooltip called on invisible tab preview");
+
+  if (FAILED(mTaskbar->SetThumbnailTooltip(PreviewWindow(), mTooltip.get())))
+    return NS_ERROR_FAILURE;
+  return NS_OK;
+}
+
+void TaskbarPreview::DrawBitmap(uint32_t width, uint32_t height,
+                                bool isPreview) {
+  nsresult rv;
+  nsCOMPtr<nsITaskbarPreviewCallback> callback =
+      do_CreateInstance("@mozilla.org/widget/taskbar-preview-callback;1", &rv);
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  ((TaskbarPreviewCallback*)callback.get())->SetPreview(this);
+
+  if (isPreview) {
+    ((TaskbarPreviewCallback*)callback.get())->SetIsPreview();
+    mController->RequestPreview(callback);
+  } else {
+    mController->RequestThumbnail(callback, width, height);
+  }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// TaskbarPreviewCallback
+
+NS_IMPL_ISUPPORTS(TaskbarPreviewCallback, nsITaskbarPreviewCallback)
+
+/* void done (in nsISupports aCanvas, in boolean aDrawBorder); */
+NS_IMETHODIMP
+TaskbarPreviewCallback::Done(nsISupports* aCanvas, bool aDrawBorder) {
+  // We create and destroy TaskbarTabPreviews from front end code in response
+  // to TabOpen and TabClose events. Each TaskbarTabPreview creates and owns a
+  // proxy HWND which it hands to Windows as a tab identifier. When a tab
+  // closes, TaskbarTabPreview Disable() method is called by front end, which
+  // destroys the proxy window and clears mProxyWindow which is the HWND
+  // returned from PreviewWindow(). So, since this is async, we should check to
+  // be sure the tab is still alive before doing all this gfx work and making
+  // dwm calls. To accomplish this we check the result of PreviewWindow().
+  if (!aCanvas || !mPreview || !mPreview->PreviewWindow() ||
+      !mPreview->IsWindowAvailable()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsIContent> content(do_QueryInterface(aCanvas));
+  auto canvas = dom::HTMLCanvasElement::FromNodeOrNull(content);
+  if (!canvas) {
+    return NS_ERROR_FAILURE;
+  }
+
+  RefPtr<gfx::SourceSurface> source = canvas->GetSurfaceSnapshot();
+  if (!source) {
+    return NS_ERROR_FAILURE;
+  }
+  RefPtr<gfxWindowsSurface> target = new gfxWindowsSurface(
+      source->GetSize(), gfx::SurfaceFormat::A8R8G8B8_UINT32);
+  if (target->CairoStatus() != CAIRO_STATUS_SUCCESS) {
+    return NS_ERROR_FAILURE;
+  }
+
+  using DataSrcSurf = gfx::DataSourceSurface;
+  RefPtr<DataSrcSurf> srcSurface = source->GetDataSurface();
+  RefPtr<gfxImageSurface> imageSurface = target->GetAsImageSurface();
+  if (!srcSurface || !imageSurface) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (DataSrcSurf::ScopedMap const sourceMap(srcSurface, DataSrcSurf::READ);
+      sourceMap.IsMapped()) {
+    mozilla::gfx::CopySurfaceDataToPackedArray(
+        sourceMap.GetData(), imageSurface->Data(), srcSurface->GetSize(),
+        sourceMap.GetStride(), BytesPerPixel(srcSurface->GetFormat()));
+  } else if (source->GetSize().IsEmpty()) {
+    // A zero-size source-surface probably shouldn't happen, but is harmless
+    // here. Fall through.
+  } else {
+    return NS_ERROR_FAILURE;
+  }
+
+  HDC hDC = target->GetDC();
+  HBITMAP hBitmap = (HBITMAP)GetCurrentObject(hDC, OBJ_BITMAP);
+
+  DWORD flags = aDrawBorder ? DWM_SIT_DISPLAYFRAME : 0;
+  HRESULT hr;
+  if (!mIsThumbnail) {
+    POINT pptClient = {0, 0};
+    hr = DwmSetIconicLivePreviewBitmap(mPreview->PreviewWindow(), hBitmap,
+                                       &pptClient, flags);
+  } else {
+    hr = DwmSetIconicThumbnail(mPreview->PreviewWindow(), hBitmap, flags);
+  }
+  MOZ_ASSERT(SUCCEEDED(hr));
+  mozilla::Unused << hr;
+  return NS_OK;
+}
+
+/* static */
+bool TaskbarPreview::MainWindowHook(void* aContext, HWND hWnd, UINT nMsg,
+                                    WPARAM wParam, LPARAM lParam,
+                                    LRESULT* aResult) {
+  NS_ASSERTION(nMsg == nsAppShell::GetTaskbarButtonCreatedMessage() ||
+                   nMsg == WM_DESTROY,
+               "Window hook proc called with wrong message");
+  NS_ASSERTION(aContext, "Null context in MainWindowHook");
+  if (!aContext) return false;
+  TaskbarPreview* preview = reinterpret_cast<TaskbarPreview*>(aContext);
+  if (nMsg == WM_DESTROY) {
+    // nsWindow is being destroyed
+    // We can't really do anything at this point including removing hooks
+    return false;
+  } else {
+    nsWindow* window = WinUtils::GetNSWindowPtr(preview->mWnd);
+    if (window) {
+      window->SetHasTaskbarIconBeenCreated();
+
+      if (preview->mVisible) preview->UpdateTaskbarProperties();
+    }
+  }
+  return false;
+}
+
+TaskbarPreview* TaskbarPreview::sActivePreview = nullptr;
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/TaskbarPreview.h b/widget/windows/TaskbarPreview.h
new file mode 100644
index 0000000000..ca21e3eeb8
--- /dev/null
+++ b/widget/windows/TaskbarPreview.h
@@ -0,0 +1,132 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_TaskbarPreview_h__
+#define __mozilla_widget_TaskbarPreview_h__
+
+#include <windows.h>
+#include <shobjidl.h>
+#undef LogSeverity  // SetupAPI.h #defines this as DWORD
+
+#include "mozilla/RefPtr.h"
+#include <nsITaskbarPreview.h>
+#include <nsITaskbarPreviewController.h>
+#include <nsString.h>
+#include <nsIWeakReferenceUtils.h>
+#include <nsIDocShell.h>
+#include "WindowHook.h"
+
+namespace mozilla {
+namespace widget {
+
+class TaskbarPreviewCallback;
+
+class TaskbarPreview : public nsITaskbarPreview {
+ public:
+  TaskbarPreview(ITaskbarList4* aTaskbar,
+                 nsITaskbarPreviewController* aController, HWND aHWND,
+                 nsIDocShell* aShell);
+  virtual nsresult Init();
+
+  friend class TaskbarPreviewCallback;
+
+  NS_DECL_NSITASKBARPREVIEW
+
+ protected:
+  virtual ~TaskbarPreview();
+
+  // Called to update ITaskbarList4 dependent properties
+  virtual nsresult UpdateTaskbarProperties();
+
+  // Invoked when the preview is made visible
+  virtual nsresult Enable();
+  // Invoked when the preview is made invisible
+  virtual nsresult Disable();
+
+  // Detaches this preview from the nsWindow instance it's tied to
+  virtual void DetachFromNSWindow();
+
+  // Determines if the window is available and a destroy has not yet started
+  bool IsWindowAvailable() const;
+
+  // Marks this preview as being active
+  virtual nsresult ShowActive(bool active) = 0;
+  // Gets a reference to the window used to handle the preview messages
+  virtual HWND& PreviewWindow() = 0;
+
+  // Window procedure for the PreviewWindow (hooked for window previews)
+  virtual LRESULT WndProc(UINT nMsg, WPARAM wParam, LPARAM lParam);
+
+  // Returns whether or not the taskbar icon has been created for mWnd The
+  // ITaskbarList4 API requires that we wait until the icon has been created
+  // before we can call its methods.
+  bool CanMakeTaskbarCalls();
+
+  // Gets the WindowHook for the nsWindow
+  WindowHook* GetWindowHook();
+
+  // Enables/disables custom drawing for the given window
+  static void EnableCustomDrawing(HWND aHWND, bool aEnable);
+
+  // MSCOM Taskbar interface
+  RefPtr<ITaskbarList4> mTaskbar;
+  // Controller for this preview
+  nsCOMPtr<nsITaskbarPreviewController> mController;
+  // The HWND to the nsWindow that this object previews
+  HWND mWnd;
+  // Whether or not this preview is visible
+  bool mVisible;
+
+ private:
+  // Called when the tooltip should be updated
+  nsresult UpdateTooltip();
+
+  // Requests the controller to draw into a canvas of the given width and
+  // height. The resulting bitmap is sent to the DWM to display.
+  void DrawBitmap(uint32_t width, uint32_t height, bool isPreview);
+
+  // WindowHook procedure for hooking mWnd
+  static bool MainWindowHook(void* aContext, HWND hWnd, UINT nMsg,
+                             WPARAM wParam, LPARAM lParam, LRESULT* aResult);
+
+  // Docshell corresponding to the <window> the nsWindow contains
+  nsWeakPtr mDocShell;
+  nsString mTooltip;
+
+  // The preview currently marked as active in the taskbar. nullptr if no
+  // preview is active (some other window is).
+  static TaskbarPreview* sActivePreview;
+};
+
+/*
+ * Callback object TaskbarPreview hands to preview controllers when we
+ * request async thumbnail or live preview images. Controllers invoke
+ * this interface once they have aquired the requested image.
+ */
+class TaskbarPreviewCallback : public nsITaskbarPreviewCallback {
+ public:
+  TaskbarPreviewCallback() : mIsThumbnail(true) {}
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITASKBARPREVIEWCALLBACK
+
+  void SetPreview(TaskbarPreview* aPreview) { mPreview = aPreview; }
+
+  void SetIsPreview() { mIsThumbnail = false; }
+
+ protected:
+  virtual ~TaskbarPreviewCallback() {}
+
+ private:
+  RefPtr<TaskbarPreview> mPreview;
+  bool mIsThumbnail;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __mozilla_widget_TaskbarPreview_h__ */
diff --git a/widget/windows/TaskbarPreviewButton.cpp b/widget/windows/TaskbarPreviewButton.cpp
new file mode 100644
index 0000000000..abbb1069a9
--- /dev/null
+++ b/widget/windows/TaskbarPreviewButton.cpp
@@ -0,0 +1,137 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <windows.h>
+#include <strsafe.h>
+
+#include "TaskbarWindowPreview.h"
+#include "TaskbarPreviewButton.h"
+#include "nsWindowGfx.h"
+#include <imgIContainer.h>
+
+namespace mozilla {
+namespace widget {
+
+NS_IMPL_ISUPPORTS(TaskbarPreviewButton, nsITaskbarPreviewButton,
+                  nsISupportsWeakReference)
+
+TaskbarPreviewButton::TaskbarPreviewButton(TaskbarWindowPreview* preview,
+                                           uint32_t index)
+    : mPreview(preview), mIndex(index) {}
+
+TaskbarPreviewButton::~TaskbarPreviewButton() { SetVisible(false); }
+
+NS_IMETHODIMP
+TaskbarPreviewButton::GetTooltip(nsAString& aTooltip) {
+  aTooltip = mTooltip;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreviewButton::SetTooltip(const nsAString& aTooltip) {
+  mTooltip = aTooltip;
+  size_t destLength = sizeof Button().szTip / (sizeof Button().szTip[0]);
+  wchar_t* tooltip = &(Button().szTip[0]);
+  StringCchCopyNW(tooltip, destLength, mTooltip.get(), mTooltip.Length());
+  return Update();
+}
+
+NS_IMETHODIMP
+TaskbarPreviewButton::GetDismissOnClick(bool* dismiss) {
+  *dismiss = (Button().dwFlags & THBF_DISMISSONCLICK) == THBF_DISMISSONCLICK;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreviewButton::SetDismissOnClick(bool dismiss) {
+  if (dismiss)
+    Button().dwFlags |= THBF_DISMISSONCLICK;
+  else
+    Button().dwFlags &= ~THBF_DISMISSONCLICK;
+  return Update();
+}
+
+NS_IMETHODIMP
+TaskbarPreviewButton::GetHasBorder(bool* hasBorder) {
+  *hasBorder = (Button().dwFlags & THBF_NOBACKGROUND) != THBF_NOBACKGROUND;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreviewButton::SetHasBorder(bool hasBorder) {
+  if (hasBorder)
+    Button().dwFlags &= ~THBF_NOBACKGROUND;
+  else
+    Button().dwFlags |= THBF_NOBACKGROUND;
+  return Update();
+}
+
+NS_IMETHODIMP
+TaskbarPreviewButton::GetDisabled(bool* disabled) {
+  *disabled = (Button().dwFlags & THBF_DISABLED) == THBF_DISABLED;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreviewButton::SetDisabled(bool disabled) {
+  if (disabled)
+    Button().dwFlags |= THBF_DISABLED;
+  else
+    Button().dwFlags &= ~THBF_DISABLED;
+  return Update();
+}
+
+NS_IMETHODIMP
+TaskbarPreviewButton::GetImage(imgIContainer** img) {
+  if (mImage)
+    NS_ADDREF(*img = mImage);
+  else
+    *img = nullptr;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreviewButton::SetImage(imgIContainer* img) {
+  if (Button().hIcon) ::DestroyIcon(Button().hIcon);
+  if (img) {
+    nsresult rv;
+    rv = nsWindowGfx::CreateIcon(
+        img, false, LayoutDeviceIntPoint(),
+        nsWindowGfx::GetIconMetrics(nsWindowGfx::kRegularIcon),
+        &Button().hIcon);
+    NS_ENSURE_SUCCESS(rv, rv);
+  } else {
+    Button().hIcon = nullptr;
+  }
+  return Update();
+}
+
+NS_IMETHODIMP
+TaskbarPreviewButton::GetVisible(bool* visible) {
+  *visible = (Button().dwFlags & THBF_HIDDEN) != THBF_HIDDEN;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarPreviewButton::SetVisible(bool visible) {
+  if (visible)
+    Button().dwFlags &= ~THBF_HIDDEN;
+  else
+    Button().dwFlags |= THBF_HIDDEN;
+  return Update();
+}
+
+THUMBBUTTON& TaskbarPreviewButton::Button() {
+  return mPreview->mThumbButtons[mIndex];
+}
+
+nsresult TaskbarPreviewButton::Update() {
+  return mPreview->UpdateButton(mIndex);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/TaskbarPreviewButton.h b/widget/windows/TaskbarPreviewButton.h
new file mode 100644
index 0000000000..e13b2d6771
--- /dev/null
+++ b/widget/windows/TaskbarPreviewButton.h
@@ -0,0 +1,47 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_TaskbarPreviewButton_h__
+#define __mozilla_widget_TaskbarPreviewButton_h__
+
+#include <windows.h>
+#include <shobjidl.h>
+#undef LogSeverity  // SetupAPI.h #defines this as DWORD
+
+#include "mozilla/RefPtr.h"
+#include <nsITaskbarPreviewButton.h>
+#include <nsString.h>
+#include "nsWeakReference.h"
+
+namespace mozilla {
+namespace widget {
+
+class TaskbarWindowPreview;
+class TaskbarPreviewButton : public nsITaskbarPreviewButton,
+                             public nsSupportsWeakReference {
+  virtual ~TaskbarPreviewButton();
+
+ public:
+  TaskbarPreviewButton(TaskbarWindowPreview* preview, uint32_t index);
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITASKBARPREVIEWBUTTON
+
+ private:
+  THUMBBUTTON& Button();
+  nsresult Update();
+
+  RefPtr<TaskbarWindowPreview> mPreview;
+  uint32_t mIndex;
+  nsString mTooltip;
+  nsCOMPtr<imgIContainer> mImage;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __mozilla_widget_TaskbarPreviewButton_h__ */
diff --git a/widget/windows/TaskbarTabPreview.cpp b/widget/windows/TaskbarTabPreview.cpp
new file mode 100644
index 0000000000..3421e68ffb
--- /dev/null
+++ b/widget/windows/TaskbarTabPreview.cpp
@@ -0,0 +1,344 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TaskbarTabPreview.h"
+#include "nsWindowGfx.h"
+#include "nsUXThemeData.h"
+#include "WinUtils.h"
+#include <nsITaskbarPreviewController.h>
+
+#define TASKBARPREVIEW_HWNDID L"TaskbarTabPreviewHwnd"
+
+namespace mozilla {
+namespace widget {
+
+NS_IMPL_ISUPPORTS(TaskbarTabPreview, nsITaskbarTabPreview)
+
+const wchar_t* const kWindowClass = L"MozillaTaskbarPreviewClass";
+
+TaskbarTabPreview::TaskbarTabPreview(ITaskbarList4* aTaskbar,
+                                     nsITaskbarPreviewController* aController,
+                                     HWND aHWND, nsIDocShell* aShell)
+    : TaskbarPreview(aTaskbar, aController, aHWND, aShell),
+      mProxyWindow(nullptr),
+      mIcon(nullptr),
+      mRegistered(false) {}
+
+TaskbarTabPreview::~TaskbarTabPreview() {
+  if (mIcon) {
+    ::DestroyIcon(mIcon);
+    mIcon = nullptr;
+  }
+
+  // We need to ensure that proxy window disappears or else Bad Things happen.
+  if (mProxyWindow) Disable();
+
+  NS_ASSERTION(!mProxyWindow, "Taskbar proxy window was not destroyed!");
+
+  if (IsWindowAvailable()) {
+    DetachFromNSWindow();
+  } else {
+    mWnd = nullptr;
+  }
+}
+
+nsresult TaskbarTabPreview::Init() {
+  nsresult rv = TaskbarPreview::Init();
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  WindowHook* hook = GetWindowHook();
+  if (!hook) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  return hook->AddMonitor(WM_WINDOWPOSCHANGED, MainWindowHook, this);
+}
+
+nsresult TaskbarTabPreview::ShowActive(bool active) {
+  NS_ASSERTION(mVisible && CanMakeTaskbarCalls(),
+               "ShowActive called on invisible window or before taskbar calls "
+               "can be made for this window");
+  return FAILED(
+             mTaskbar->SetTabActive(active ? mProxyWindow : nullptr, mWnd, 0))
+             ? NS_ERROR_FAILURE
+             : NS_OK;
+}
+
+HWND& TaskbarTabPreview::PreviewWindow() { return mProxyWindow; }
+
+nativeWindow TaskbarTabPreview::GetHWND() { return mProxyWindow; }
+
+void TaskbarTabPreview::EnsureRegistration() {
+  NS_ASSERTION(mVisible && CanMakeTaskbarCalls(),
+               "EnsureRegistration called when it is not safe to do so");
+
+  (void)UpdateTaskbarProperties();
+}
+
+NS_IMETHODIMP
+TaskbarTabPreview::GetTitle(nsAString& aTitle) {
+  aTitle = mTitle;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarTabPreview::SetTitle(const nsAString& aTitle) {
+  mTitle = aTitle;
+  return mVisible ? UpdateTitle() : NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarTabPreview::SetIcon(imgIContainer* icon) {
+  HICON hIcon = nullptr;
+  if (icon) {
+    nsresult rv;
+    rv = nsWindowGfx::CreateIcon(
+        icon, false, LayoutDeviceIntPoint(),
+        nsWindowGfx::GetIconMetrics(nsWindowGfx::kSmallIcon), &hIcon);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (mIcon) ::DestroyIcon(mIcon);
+  mIcon = hIcon;
+  mIconImage = icon;
+  return mVisible ? UpdateIcon() : NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarTabPreview::GetIcon(imgIContainer** icon) {
+  NS_IF_ADDREF(*icon = mIconImage);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarTabPreview::Move(nsITaskbarTabPreview* aNext) {
+  if (aNext == this) return NS_ERROR_INVALID_ARG;
+  mNext = aNext;
+  return CanMakeTaskbarCalls() ? UpdateNext() : NS_OK;
+}
+
+nsresult TaskbarTabPreview::UpdateTaskbarProperties() {
+  if (mRegistered) return NS_OK;
+
+  if (FAILED(mTaskbar->RegisterTab(mProxyWindow, mWnd)))
+    return NS_ERROR_FAILURE;
+
+  nsresult rv = UpdateNext();
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = TaskbarPreview::UpdateTaskbarProperties();
+  mRegistered = true;
+  return rv;
+}
+
+LRESULT
+TaskbarTabPreview::WndProc(UINT nMsg, WPARAM wParam, LPARAM lParam) {
+  RefPtr<TaskbarTabPreview> kungFuDeathGrip(this);
+  switch (nMsg) {
+    case WM_CREATE:
+      TaskbarPreview::EnableCustomDrawing(mProxyWindow, true);
+      return 0;
+    case WM_CLOSE:
+      mController->OnClose();
+      return 0;
+    case WM_ACTIVATE:
+      if (LOWORD(wParam) == WA_ACTIVE) {
+        // Activate the tab the user selected then restore the main window,
+        // keeping normal/max window state intact.
+        bool activateWindow;
+        nsresult rv = mController->OnActivate(&activateWindow);
+        if (NS_SUCCEEDED(rv) && activateWindow) {
+          nsWindow* win = WinUtils::GetNSWindowPtr(mWnd);
+          if (win) {
+            nsWindow* parent = win->GetTopLevelWindow(true);
+            if (parent) {
+              parent->Show(true);
+            }
+          }
+        }
+      }
+      return 0;
+    case WM_GETICON:
+      return (LRESULT)mIcon;
+    case WM_SYSCOMMAND:
+      // Send activation events to the top level window and select the proper
+      // tab through the controller.
+      if (wParam == SC_RESTORE || wParam == SC_MAXIMIZE) {
+        bool activateWindow;
+        nsresult rv = mController->OnActivate(&activateWindow);
+        if (NS_SUCCEEDED(rv) && activateWindow) {
+          // Note, restoring an iconic, maximized window here will only
+          // activate the maximized window. This is not a bug, it's default
+          // windows behavior.
+          ::SendMessageW(mWnd, WM_SYSCOMMAND, wParam, lParam);
+        }
+        return 0;
+      }
+      // Forward everything else to the top level window. Do not forward
+      // close since that's intended for the tab. When the preview proxy
+      // closes, we'll close the tab above.
+      return wParam == SC_CLOSE
+                 ? ::DefWindowProcW(mProxyWindow, WM_SYSCOMMAND, wParam, lParam)
+                 : ::SendMessageW(mWnd, WM_SYSCOMMAND, wParam, lParam);
+  }
+  return TaskbarPreview::WndProc(nMsg, wParam, lParam);
+}
+
+/* static */
+LRESULT CALLBACK TaskbarTabPreview::GlobalWndProc(HWND hWnd, UINT nMsg,
+                                                  WPARAM wParam,
+                                                  LPARAM lParam) {
+  TaskbarTabPreview* preview(nullptr);
+  if (nMsg == WM_CREATE) {
+    CREATESTRUCT* cs = reinterpret_cast<CREATESTRUCT*>(lParam);
+    preview = reinterpret_cast<TaskbarTabPreview*>(cs->lpCreateParams);
+    if (!::SetPropW(hWnd, TASKBARPREVIEW_HWNDID, preview))
+      NS_ERROR("Could not associate native window with tab preview");
+    preview->mProxyWindow = hWnd;
+  } else {
+    preview = reinterpret_cast<TaskbarTabPreview*>(
+        ::GetPropW(hWnd, TASKBARPREVIEW_HWNDID));
+    if (nMsg == WM_DESTROY) ::RemovePropW(hWnd, TASKBARPREVIEW_HWNDID);
+  }
+
+  if (preview) return preview->WndProc(nMsg, wParam, lParam);
+  return ::DefWindowProcW(hWnd, nMsg, wParam, lParam);
+}
+
+nsresult TaskbarTabPreview::Enable() {
+  WNDCLASSW wc;
+  HINSTANCE module = GetModuleHandle(nullptr);
+
+  if (!GetClassInfoW(module, kWindowClass, &wc)) {
+    wc.style = 0;
+    wc.lpfnWndProc = GlobalWndProc;
+    wc.cbClsExtra = 0;
+    wc.cbWndExtra = 0;
+    wc.hInstance = module;
+    wc.hIcon = nullptr;
+    wc.hCursor = nullptr;
+    wc.hbrBackground = (HBRUSH) nullptr;
+    wc.lpszMenuName = (LPCWSTR) nullptr;
+    wc.lpszClassName = kWindowClass;
+    RegisterClassW(&wc);
+  }
+  ::CreateWindowW(kWindowClass, L"TaskbarPreviewWindow",
+                  WS_CAPTION | WS_SYSMENU, 0, 0, 200, 60, nullptr, nullptr,
+                  module, this);
+  // GlobalWndProc will set mProxyWindow so that WM_CREATE can have a valid HWND
+  if (!mProxyWindow) return NS_ERROR_INVALID_ARG;
+
+  UpdateProxyWindowStyle();
+
+  nsresult rv = TaskbarPreview::Enable();
+  nsresult rvUpdate;
+  rvUpdate = UpdateTitle();
+  if (NS_FAILED(rvUpdate)) rv = rvUpdate;
+
+  rvUpdate = UpdateIcon();
+  if (NS_FAILED(rvUpdate)) rv = rvUpdate;
+
+  return rv;
+}
+
+nsresult TaskbarTabPreview::Disable() {
+  // TaskbarPreview::Disable assumes that mWnd is valid but this method can be
+  // called when it is null iff the nsWindow has already been destroyed and we
+  // are still visible for some reason during object destruction.
+  if (mWnd) TaskbarPreview::Disable();
+
+  if (FAILED(mTaskbar->UnregisterTab(mProxyWindow))) return NS_ERROR_FAILURE;
+  mRegistered = false;
+
+  // TaskbarPreview::WndProc will set mProxyWindow to null
+  if (!DestroyWindow(mProxyWindow)) return NS_ERROR_FAILURE;
+  mProxyWindow = nullptr;
+  return NS_OK;
+}
+
+void TaskbarTabPreview::DetachFromNSWindow() {
+  (void)SetVisible(false);
+  if (WindowHook* hook = GetWindowHook()) {
+    hook->RemoveMonitor(WM_WINDOWPOSCHANGED, MainWindowHook, this);
+  }
+  TaskbarPreview::DetachFromNSWindow();
+}
+
+/* static */
+bool TaskbarTabPreview::MainWindowHook(void* aContext, HWND hWnd, UINT nMsg,
+                                       WPARAM wParam, LPARAM lParam,
+                                       LRESULT* aResult) {
+  if (nMsg == WM_WINDOWPOSCHANGED) {
+    TaskbarTabPreview* preview = reinterpret_cast<TaskbarTabPreview*>(aContext);
+    WINDOWPOS* pos = reinterpret_cast<WINDOWPOS*>(lParam);
+    if (SWP_FRAMECHANGED == (pos->flags & SWP_FRAMECHANGED))
+      preview->UpdateProxyWindowStyle();
+  } else {
+    MOZ_ASSERT_UNREACHABLE(
+        "Style changed hook fired on non-style changed "
+        "message");
+  }
+  return false;
+}
+
+void TaskbarTabPreview::UpdateProxyWindowStyle() {
+  if (!mProxyWindow) return;
+
+  DWORD minMaxMask = WS_MINIMIZE | WS_MAXIMIZE;
+  DWORD windowStyle = GetWindowLongW(mWnd, GWL_STYLE);
+
+  DWORD proxyStyle = GetWindowLongW(mProxyWindow, GWL_STYLE);
+  proxyStyle &= ~minMaxMask;
+  proxyStyle |= windowStyle & minMaxMask;
+  SetWindowLongW(mProxyWindow, GWL_STYLE, proxyStyle);
+
+  DWORD exStyle =
+      (WS_MAXIMIZE == (windowStyle & WS_MAXIMIZE)) ? WS_EX_TOOLWINDOW : 0;
+  SetWindowLongW(mProxyWindow, GWL_EXSTYLE, exStyle);
+}
+
+nsresult TaskbarTabPreview::UpdateTitle() {
+  NS_ASSERTION(mVisible, "UpdateTitle called on invisible preview");
+
+  if (!::SetWindowTextW(mProxyWindow, mTitle.get())) return NS_ERROR_FAILURE;
+  return NS_OK;
+}
+
+nsresult TaskbarTabPreview::UpdateIcon() {
+  NS_ASSERTION(mVisible, "UpdateIcon called on invisible preview");
+
+  ::SendMessageW(mProxyWindow, WM_SETICON, ICON_SMALL, (LPARAM)mIcon);
+
+  return NS_OK;
+}
+
+nsresult TaskbarTabPreview::UpdateNext() {
+  NS_ASSERTION(CanMakeTaskbarCalls() && mVisible,
+               "UpdateNext called on invisible tab preview");
+  HWND hNext = nullptr;
+  if (mNext) {
+    bool visible;
+    nsresult rv = mNext->GetVisible(&visible);
+
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Can only move next to enabled previews
+    if (!visible) return NS_ERROR_FAILURE;
+
+    hNext = (HWND)mNext->GetHWND();
+
+    // hNext must be registered with the taskbar if the call is to succeed
+    mNext->EnsureRegistration();
+  }
+  if (FAILED(mTaskbar->SetTabOrder(mProxyWindow, hNext)))
+    return NS_ERROR_FAILURE;
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/TaskbarTabPreview.h b/widget/windows/TaskbarTabPreview.h
new file mode 100644
index 0000000000..9a15760557
--- /dev/null
+++ b/widget/windows/TaskbarTabPreview.h
@@ -0,0 +1,70 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_TaskbarTabPreview_h__
+#define __mozilla_widget_TaskbarTabPreview_h__
+
+#include "nsITaskbarTabPreview.h"
+#include "TaskbarPreview.h"
+
+namespace mozilla {
+namespace widget {
+
+class TaskbarTabPreview : public nsITaskbarTabPreview, public TaskbarPreview {
+  virtual ~TaskbarTabPreview();
+
+ public:
+  TaskbarTabPreview(ITaskbarList4* aTaskbar,
+                    nsITaskbarPreviewController* aController, HWND aHWND,
+                    nsIDocShell* aShell);
+  virtual nsresult Init() override;
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITASKBARTABPREVIEW
+  NS_FORWARD_NSITASKBARPREVIEW(TaskbarPreview::)
+
+ private:
+  virtual nsresult ShowActive(bool active);
+  virtual HWND& PreviewWindow();
+  virtual LRESULT WndProc(UINT nMsg, WPARAM wParam, LPARAM lParam);
+  static LRESULT CALLBACK GlobalWndProc(HWND hWnd, UINT nMsg, WPARAM wParam,
+                                        LPARAM lParam);
+
+  virtual nsresult UpdateTaskbarProperties();
+  virtual nsresult Enable();
+  virtual nsresult Disable();
+  virtual void DetachFromNSWindow();
+
+  // WindowHook procedure for hooking mWnd
+  static bool MainWindowHook(void* aContext, HWND hWnd, UINT nMsg,
+                             WPARAM wParam, LPARAM lParam, LRESULT* aResult);
+
+  // Bug 520807 - we need to update the proxy window style based on the main
+  // window's style to workaround a bug with the way the DWM displays the
+  // previews.
+  void UpdateProxyWindowStyle();
+
+  nsresult UpdateTitle();
+  nsresult UpdateIcon();
+  nsresult UpdateNext();
+
+  // Handle to the toplevel proxy window
+  HWND mProxyWindow;
+  nsString mTitle;
+  nsCOMPtr<imgIContainer> mIconImage;
+  // Cached Windows icon of mIconImage
+  HICON mIcon;
+  // Preview that follows this preview in the taskbar (left-to-right order)
+  nsCOMPtr<nsITaskbarTabPreview> mNext;
+  // True if this preview has been registered with the taskbar
+  bool mRegistered;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __mozilla_widget_TaskbarTabPreview_h__ */
diff --git a/widget/windows/TaskbarWindowPreview.cpp b/widget/windows/TaskbarWindowPreview.cpp
new file mode 100644
index 0000000000..212278be4a
--- /dev/null
+++ b/widget/windows/TaskbarWindowPreview.cpp
@@ -0,0 +1,326 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+
+#include <nsITaskbarPreviewController.h>
+#include "TaskbarWindowPreview.h"
+#include "WindowHook.h"
+#include "nsUXThemeData.h"
+#include "TaskbarPreviewButton.h"
+#include "nsWindow.h"
+#include "nsWindowGfx.h"
+
+namespace mozilla {
+namespace widget {
+
+namespace {
+bool WindowHookProc(void* aContext, HWND hWnd, UINT nMsg, WPARAM wParam,
+                    LPARAM lParam, LRESULT* aResult) {
+  TaskbarWindowPreview* preview =
+      reinterpret_cast<TaskbarWindowPreview*>(aContext);
+  *aResult = preview->WndProc(nMsg, wParam, lParam);
+  return true;
+}
+}  // namespace
+
+NS_IMPL_ISUPPORTS(TaskbarWindowPreview, nsITaskbarWindowPreview,
+                  nsITaskbarProgress, nsITaskbarOverlayIconController,
+                  nsISupportsWeakReference)
+
+/**
+ * These correspond directly to the states defined in nsITaskbarProgress.idl, so
+ * they should be kept in sync.
+ */
+static TBPFLAG sNativeStates[] = {TBPF_NOPROGRESS, TBPF_INDETERMINATE,
+                                  TBPF_NORMAL, TBPF_ERROR, TBPF_PAUSED};
+
+TaskbarWindowPreview::TaskbarWindowPreview(
+    ITaskbarList4* aTaskbar, nsITaskbarPreviewController* aController,
+    HWND aHWND, nsIDocShell* aShell)
+    : TaskbarPreview(aTaskbar, aController, aHWND, aShell),
+      mCustomDrawing(false),
+      mHaveButtons(false),
+      mState(TBPF_NOPROGRESS),
+      mCurrentValue(0),
+      mMaxValue(0),
+      mOverlayIcon(nullptr) {
+  // Window previews are visible by default
+  (void)SetVisible(true);
+
+  memset(mThumbButtons, 0, sizeof mThumbButtons);
+  for (int32_t i = 0; i < nsITaskbarWindowPreview::NUM_TOOLBAR_BUTTONS; i++) {
+    mThumbButtons[i].dwMask = THB_FLAGS | THB_ICON | THB_TOOLTIP;
+    mThumbButtons[i].iId = i;
+    mThumbButtons[i].dwFlags = THBF_HIDDEN;
+  }
+}
+
+TaskbarWindowPreview::~TaskbarWindowPreview() {
+  if (mOverlayIcon) {
+    ::DestroyIcon(mOverlayIcon);
+    mOverlayIcon = nullptr;
+  }
+
+  // We need to clean up a hook associated with the "this" pointer.
+  SetVisible(false);
+
+  if (IsWindowAvailable()) {
+    DetachFromNSWindow();
+  } else {
+    mWnd = nullptr;
+  }
+}
+
+nsresult TaskbarWindowPreview::Init() {
+  nsresult rv = TaskbarPreview::Init();
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  if (CanMakeTaskbarCalls()) {
+    return NS_OK;
+  }
+
+  WindowHook* hook = GetWindowHook();
+  if (!hook) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  return hook->AddMonitor(nsAppShell::GetTaskbarButtonCreatedMessage(),
+                          TaskbarWindowHook, this);
+}
+
+nsresult TaskbarWindowPreview::ShowActive(bool active) {
+  return FAILED(mTaskbar->ActivateTab(active ? mWnd : nullptr))
+             ? NS_ERROR_FAILURE
+             : NS_OK;
+}
+
+HWND& TaskbarWindowPreview::PreviewWindow() { return mWnd; }
+
+nsresult TaskbarWindowPreview::GetButton(uint32_t index,
+                                         nsITaskbarPreviewButton** _retVal) {
+  if (index >= nsITaskbarWindowPreview::NUM_TOOLBAR_BUTTONS)
+    return NS_ERROR_INVALID_ARG;
+
+  nsCOMPtr<nsITaskbarPreviewButton> button(
+      do_QueryReferent(mWeakButtons[index]));
+
+  if (!button) {
+    // Lost reference
+    button = new TaskbarPreviewButton(this, index);
+    if (!button) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+    mWeakButtons[index] = do_GetWeakReference(button);
+  }
+
+  if (!mHaveButtons) {
+    mHaveButtons = true;
+
+    WindowHook* hook = GetWindowHook();
+    if (!hook) {
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+    (void)hook->AddHook(WM_COMMAND, WindowHookProc, this);
+
+    if (mVisible && FAILED(mTaskbar->ThumbBarAddButtons(
+                        mWnd, nsITaskbarWindowPreview::NUM_TOOLBAR_BUTTONS,
+                        mThumbButtons))) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+  button.forget(_retVal);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarWindowPreview::SetEnableCustomDrawing(bool aEnable) {
+  if (aEnable == mCustomDrawing) return NS_OK;
+
+  WindowHook* hook = GetWindowHook();
+  if (!hook) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  mCustomDrawing = aEnable;
+  TaskbarPreview::EnableCustomDrawing(mWnd, aEnable);
+
+  if (aEnable) {
+    (void)hook->AddHook(WM_DWMSENDICONICTHUMBNAIL, WindowHookProc, this);
+    (void)hook->AddHook(WM_DWMSENDICONICLIVEPREVIEWBITMAP, WindowHookProc,
+                        this);
+  } else {
+    (void)hook->RemoveHook(WM_DWMSENDICONICLIVEPREVIEWBITMAP, WindowHookProc,
+                           this);
+    (void)hook->RemoveHook(WM_DWMSENDICONICTHUMBNAIL, WindowHookProc, this);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarWindowPreview::GetEnableCustomDrawing(bool* aEnable) {
+  *aEnable = mCustomDrawing;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarWindowPreview::SetProgressState(nsTaskbarProgressState aState,
+                                       uint64_t aCurrentValue,
+                                       uint64_t aMaxValue) {
+  NS_ENSURE_ARG_RANGE(aState, nsTaskbarProgressState(0),
+                      nsTaskbarProgressState(ArrayLength(sNativeStates) - 1));
+
+  TBPFLAG nativeState = sNativeStates[aState];
+  if (nativeState == TBPF_NOPROGRESS || nativeState == TBPF_INDETERMINATE) {
+    NS_ENSURE_TRUE(aCurrentValue == 0, NS_ERROR_INVALID_ARG);
+    NS_ENSURE_TRUE(aMaxValue == 0, NS_ERROR_INVALID_ARG);
+  }
+
+  if (aCurrentValue > aMaxValue) return NS_ERROR_ILLEGAL_VALUE;
+
+  mState = nativeState;
+  mCurrentValue = aCurrentValue;
+  mMaxValue = aMaxValue;
+
+  // Only update if we can
+  return CanMakeTaskbarCalls() ? UpdateTaskbarProgress() : NS_OK;
+}
+
+NS_IMETHODIMP
+TaskbarWindowPreview::SetOverlayIcon(imgIContainer* aStatusIcon,
+                                     const nsAString& aStatusDescription) {
+  nsresult rv;
+  if (aStatusIcon) {
+    // The image shouldn't be animated
+    bool isAnimated;
+    rv = aStatusIcon->GetAnimated(&isAnimated);
+    NS_ENSURE_SUCCESS(rv, rv);
+    NS_ENSURE_FALSE(isAnimated, NS_ERROR_INVALID_ARG);
+  }
+
+  HICON hIcon = nullptr;
+  if (aStatusIcon) {
+    rv = nsWindowGfx::CreateIcon(
+        aStatusIcon, false, LayoutDeviceIntPoint(),
+        nsWindowGfx::GetIconMetrics(nsWindowGfx::kSmallIcon), &hIcon);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  if (mOverlayIcon) ::DestroyIcon(mOverlayIcon);
+  mOverlayIcon = hIcon;
+  mIconDescription = aStatusDescription;
+
+  // Only update if we can
+  return CanMakeTaskbarCalls() ? UpdateOverlayIcon() : NS_OK;
+}
+
+nsresult TaskbarWindowPreview::UpdateTaskbarProperties() {
+  if (mHaveButtons) {
+    if (FAILED(mTaskbar->ThumbBarAddButtons(
+            mWnd, nsITaskbarWindowPreview::NUM_TOOLBAR_BUTTONS, mThumbButtons)))
+      return NS_ERROR_FAILURE;
+  }
+  nsresult rv = UpdateTaskbarProgress();
+  NS_ENSURE_SUCCESS(rv, rv);
+  rv = UpdateOverlayIcon();
+  NS_ENSURE_SUCCESS(rv, rv);
+  return TaskbarPreview::UpdateTaskbarProperties();
+}
+
+nsresult TaskbarWindowPreview::UpdateTaskbarProgress() {
+  HRESULT hr = mTaskbar->SetProgressState(mWnd, mState);
+  if (SUCCEEDED(hr) && mState != TBPF_NOPROGRESS &&
+      mState != TBPF_INDETERMINATE)
+    hr = mTaskbar->SetProgressValue(mWnd, mCurrentValue, mMaxValue);
+
+  return SUCCEEDED(hr) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+nsresult TaskbarWindowPreview::UpdateOverlayIcon() {
+  HRESULT hr =
+      mTaskbar->SetOverlayIcon(mWnd, mOverlayIcon, mIconDescription.get());
+  return SUCCEEDED(hr) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+LRESULT
+TaskbarWindowPreview::WndProc(UINT nMsg, WPARAM wParam, LPARAM lParam) {
+  RefPtr<TaskbarWindowPreview> kungFuDeathGrip(this);
+  switch (nMsg) {
+    case WM_COMMAND: {
+      uint32_t id = LOWORD(wParam);
+      uint32_t index = id;
+      nsCOMPtr<nsITaskbarPreviewButton> button;
+      nsresult rv = GetButton(index, getter_AddRefs(button));
+      if (NS_SUCCEEDED(rv)) mController->OnClick(button);
+    }
+      return 0;
+  }
+  return TaskbarPreview::WndProc(nMsg, wParam, lParam);
+}
+
+/* static */
+bool TaskbarWindowPreview::TaskbarWindowHook(void* aContext, HWND hWnd,
+                                             UINT nMsg, WPARAM wParam,
+                                             LPARAM lParam, LRESULT* aResult) {
+  NS_ASSERTION(nMsg == nsAppShell::GetTaskbarButtonCreatedMessage(),
+               "Window hook proc called with wrong message");
+  TaskbarWindowPreview* preview =
+      reinterpret_cast<TaskbarWindowPreview*>(aContext);
+  // Now we can make all the calls to mTaskbar
+  preview->UpdateTaskbarProperties();
+  return false;
+}
+
+nsresult TaskbarWindowPreview::Enable() {
+  nsresult rv = TaskbarPreview::Enable();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return FAILED(mTaskbar->AddTab(mWnd)) ? NS_ERROR_FAILURE : NS_OK;
+}
+
+nsresult TaskbarWindowPreview::Disable() {
+  nsresult rv = TaskbarPreview::Disable();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return FAILED(mTaskbar->DeleteTab(mWnd)) ? NS_ERROR_FAILURE : NS_OK;
+}
+
+void TaskbarWindowPreview::DetachFromNSWindow() {
+  // Remove the hooks we have for drawing
+  SetEnableCustomDrawing(false);
+
+  if (WindowHook* hook = GetWindowHook()) {
+    (void)hook->RemoveHook(WM_COMMAND, WindowHookProc, this);
+    (void)hook->RemoveMonitor(nsAppShell::GetTaskbarButtonCreatedMessage(),
+                              TaskbarWindowHook, this);
+  }
+  TaskbarPreview::DetachFromNSWindow();
+}
+
+nsresult TaskbarWindowPreview::UpdateButtons() {
+  NS_ASSERTION(mVisible, "UpdateButtons called on invisible preview");
+
+  if (FAILED(mTaskbar->ThumbBarUpdateButtons(
+          mWnd, nsITaskbarWindowPreview::NUM_TOOLBAR_BUTTONS, mThumbButtons)))
+    return NS_ERROR_FAILURE;
+  return NS_OK;
+}
+
+nsresult TaskbarWindowPreview::UpdateButton(uint32_t index) {
+  if (index >= nsITaskbarWindowPreview::NUM_TOOLBAR_BUTTONS)
+    return NS_ERROR_INVALID_ARG;
+  if (mVisible) {
+    if (FAILED(mTaskbar->ThumbBarUpdateButtons(mWnd, 1, &mThumbButtons[index])))
+      return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/TaskbarWindowPreview.h b/widget/windows/TaskbarWindowPreview.h
new file mode 100644
index 0000000000..97c074197c
--- /dev/null
+++ b/widget/windows/TaskbarWindowPreview.h
@@ -0,0 +1,85 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_widget_TaskbarWindowPreview_h__
+#define __mozilla_widget_TaskbarWindowPreview_h__
+
+#include "nsITaskbarWindowPreview.h"
+#include "nsITaskbarProgress.h"
+#include "nsITaskbarOverlayIconController.h"
+#include "TaskbarPreview.h"
+#include "nsWeakReference.h"
+
+namespace mozilla {
+namespace widget {
+
+class TaskbarPreviewButton;
+class TaskbarWindowPreview : public TaskbarPreview,
+                             public nsITaskbarWindowPreview,
+                             public nsITaskbarProgress,
+                             public nsITaskbarOverlayIconController,
+                             public nsSupportsWeakReference {
+  virtual ~TaskbarWindowPreview();
+
+ public:
+  TaskbarWindowPreview(ITaskbarList4* aTaskbar,
+                       nsITaskbarPreviewController* aController, HWND aHWND,
+                       nsIDocShell* aShell);
+  virtual nsresult Init() override;
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITASKBARWINDOWPREVIEW
+  NS_DECL_NSITASKBARPROGRESS
+  NS_DECL_NSITASKBAROVERLAYICONCONTROLLER
+  NS_FORWARD_NSITASKBARPREVIEW(TaskbarPreview::)
+
+  virtual LRESULT WndProc(UINT nMsg, WPARAM wParam, LPARAM lParam) override;
+
+ private:
+  virtual nsresult ShowActive(bool active) override;
+  virtual HWND& PreviewWindow() override;
+
+  virtual nsresult UpdateTaskbarProperties() override;
+  virtual nsresult Enable() override;
+  virtual nsresult Disable() override;
+  virtual void DetachFromNSWindow() override;
+  nsresult UpdateButton(uint32_t index);
+  nsresult UpdateButtons();
+
+  // Is custom drawing enabled?
+  bool mCustomDrawing;
+  // Have we made any buttons?
+  bool mHaveButtons;
+  // Windows button format
+  THUMBBUTTON mThumbButtons[nsITaskbarWindowPreview::NUM_TOOLBAR_BUTTONS];
+  // Pointers to our button class (cached instances)
+  nsWeakPtr mWeakButtons[nsITaskbarWindowPreview::NUM_TOOLBAR_BUTTONS];
+
+  // Called to update ITaskbarList4 dependent properties
+  nsresult UpdateTaskbarProgress();
+  nsresult UpdateOverlayIcon();
+
+  // The taskbar progress
+  TBPFLAG mState;
+  ULONGLONG mCurrentValue;
+  ULONGLONG mMaxValue;
+
+  // Taskbar overlay icon
+  HICON mOverlayIcon;
+  nsString mIconDescription;
+
+  // WindowHook procedure for hooking mWnd for taskbar progress and icon stuff
+  static bool TaskbarWindowHook(void* aContext, HWND hWnd, UINT nMsg,
+                                WPARAM wParam, LPARAM lParam, LRESULT* aResult);
+
+  friend class TaskbarPreviewButton;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __mozilla_widget_TaskbarWindowPreview_h__ */
diff --git a/widget/windows/ToastNotification.cpp b/widget/windows/ToastNotification.cpp
new file mode 100644
index 0000000000..afdffc19ac
--- /dev/null
+++ b/widget/windows/ToastNotification.cpp
@@ -0,0 +1,915 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ToastNotification.h"
+
+#include <windows.h>
+#include <appmodel.h>
+#include <ktmw32.h>
+#include <windows.foundation.h>
+#include <wrl/client.h>
+
+#include "ErrorList.h"
+#include "mozilla/BasePrincipal.h"
+#include "mozilla/Buffer.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/DynamicallyLinkedFunctionPtr.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/mscom/COMWrappers.h"
+#include "mozilla/mscom/Utils.h"
+#include "mozilla/widget/WinRegistry.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Services.h"
+#include "mozilla/WidgetUtils.h"
+#include "nsAppRunner.h"
+#include "nsComponentManagerUtils.h"
+#include "nsCOMPtr.h"
+#include "nsIObserverService.h"
+#include "nsIWindowMediator.h"
+#include "nsPIDOMWindow.h"
+#include "nsString.h"
+#include "nsThreadUtils.h"
+#include "nsWindowsHelpers.h"
+#include "nsXREDirProvider.h"
+#include "prenv.h"
+#include "ToastNotificationHandler.h"
+#include "ToastNotificationHeaderOnlyUtils.h"
+
+namespace mozilla {
+namespace widget {
+
+using namespace toastnotification;
+
+using namespace ABI::Windows::Foundation;
+using namespace Microsoft::WRL;
+using namespace Microsoft::WRL::Wrappers;
+// Needed to disambiguate internal and Windows `ToastNotification` classes.
+using namespace ABI::Windows::UI::Notifications;
+using WinToastNotification = ABI::Windows::UI::Notifications::ToastNotification;
+using IVectorView_ToastNotification =
+    ABI::Windows::Foundation::Collections::IVectorView<WinToastNotification*>;
+using IVectorView_ScheduledToastNotification =
+    ABI::Windows::Foundation::Collections::IVectorView<
+        ScheduledToastNotification*>;
+
+LazyLogModule sWASLog("WindowsAlertsService");
+
+NS_IMPL_ISUPPORTS(ToastNotification, nsIAlertsService, nsIWindowsAlertsService,
+                  nsIAlertsDoNotDisturb, nsIObserver)
+
+ToastNotification::ToastNotification() = default;
+
+ToastNotification::~ToastNotification() = default;
+
+nsresult ToastNotification::Init() {
+  if (!PR_GetEnv("XPCSHELL_TEST_PROFILE_DIR")) {
+    // Windows Toast Notification requires AppId.  But allow `xpcshell` to
+    // create the service to test other functionality.
+    if (!EnsureAumidRegistered()) {
+      MOZ_LOG(sWASLog, LogLevel::Warning, ("Failed to register AUMID!"));
+      return NS_ERROR_NOT_IMPLEMENTED;
+    }
+  } else {
+    MOZ_LOG(sWASLog, LogLevel::Info, ("Using dummy AUMID in xpcshell test"));
+    mAumid.emplace(u"XpcshellTestToastAumid"_ns);
+  }
+
+  MOZ_LOG(sWASLog, LogLevel::Info,
+          ("Using AUMID: '%s'", NS_ConvertUTF16toUTF8(mAumid.ref()).get()));
+
+  nsCOMPtr<nsIObserverService> obsServ =
+      mozilla::services::GetObserverService();
+  if (obsServ) {
+    Unused << NS_WARN_IF(
+        NS_FAILED(obsServ->AddObserver(this, "last-pb-context-exited", false)));
+    Unused << NS_WARN_IF(
+        NS_FAILED(obsServ->AddObserver(this, "quit-application", false)));
+  }
+
+  return NS_OK;
+}
+
+bool ToastNotification::EnsureAumidRegistered() {
+  // Check if this is an MSIX install, app identity is provided by the package
+  // so no registration is necessary.
+  if (AssignIfMsixAumid(mAumid)) {
+    MOZ_LOG(
+        sWASLog, LogLevel::Info,
+        ("Found MSIX AUMID: '%s'", NS_ConvertUTF16toUTF8(mAumid.ref()).get()));
+    return true;
+  }
+
+  nsAutoString installHash;
+  nsresult rv = gDirServiceProvider->GetInstallHash(installHash);
+  NS_ENSURE_SUCCESS(rv, false);
+
+  // Check if toasts were registered during NSIS/MSI installation.
+  if (AssignIfNsisAumid(installHash, mAumid)) {
+    MOZ_LOG(sWASLog, LogLevel::Info,
+            ("Found AUMID from installer (with install hash '%s'): '%s'",
+             NS_ConvertUTF16toUTF8(installHash).get(),
+             NS_ConvertUTF16toUTF8(mAumid.ref()).get()));
+    return true;
+  }
+
+  // No AUMID registered, fall through to runtime registration for development
+  // and portable builds.
+  if (RegisterRuntimeAumid(installHash, mAumid)) {
+    MOZ_LOG(
+        sWASLog, LogLevel::Info,
+        ("Updated AUMID registration at runtime (for install hash '%s'): '%s'",
+         NS_ConvertUTF16toUTF8(installHash).get(),
+         NS_ConvertUTF16toUTF8(mAumid.ref()).get()));
+    return true;
+  }
+
+  MOZ_LOG(sWASLog, LogLevel::Warning,
+          ("Failed to register AUMID at runtime! (for install hash '%s')",
+           NS_ConvertUTF16toUTF8(installHash).get()));
+  return false;
+}
+
+bool ToastNotification::AssignIfMsixAumid(Maybe<nsAutoString>& aAumid) {
+  UINT32 len = 0;
+  // ERROR_INSUFFICIENT_BUFFER signals that we're in an MSIX package, and
+  // therefore should use the package's AUMID.
+  if (GetCurrentApplicationUserModelId(&len, nullptr) !=
+      ERROR_INSUFFICIENT_BUFFER) {
+    MOZ_LOG(sWASLog, LogLevel::Debug, ("Not an MSIX package"));
+    return false;
+  }
+  mozilla::Buffer<wchar_t> buffer(len);
+  LONG success = GetCurrentApplicationUserModelId(&len, buffer.Elements());
+  NS_ENSURE_TRUE(success == ERROR_SUCCESS, false);
+
+  aAumid.emplace(buffer.Elements());
+  return true;
+}
+
+bool ToastNotification::AssignIfNsisAumid(nsAutoString& aInstallHash,
+                                          Maybe<nsAutoString>& aAumid) {
+  nsAutoString nsisAumidName =
+      u""_ns MOZ_TOAST_APP_NAME u"Toast-"_ns + aInstallHash;
+  nsAutoString nsisAumidPath = u"AppUserModelId\\"_ns + nsisAumidName;
+  if (!WinRegistry::HasKey(HKEY_CLASSES_ROOT, nsisAumidPath)) {
+    MOZ_LOG(sWASLog, LogLevel::Debug,
+            ("No CustomActivator value from installer in key 'HKCR\\%s'",
+             NS_ConvertUTF16toUTF8(nsisAumidPath).get()));
+    return false;
+  }
+
+  aAumid.emplace(nsisAumidName);
+  return true;
+}
+
+bool ToastNotification::RegisterRuntimeAumid(nsAutoString& aInstallHash,
+                                             Maybe<nsAutoString>& aAumid) {
+  // Portable AUMID slightly differs from installed AUMID so we can
+  // differentiate installed to HKCU vs portable installs if necessary.
+  nsAutoString portableAumid =
+      u""_ns MOZ_TOAST_APP_NAME u"PortableToast-"_ns + aInstallHash;
+
+  nsCOMPtr<nsIFile> appdir;
+  nsresult rv = gDirServiceProvider->GetGREDir()->Clone(getter_AddRefs(appdir));
+  NS_ENSURE_SUCCESS(rv, false);
+
+  nsCOMPtr<nsIFile> icon;
+  rv = appdir->Clone(getter_AddRefs(icon));
+  NS_ENSURE_SUCCESS(rv, false);
+
+  rv = icon->Append(u"browser"_ns);
+  NS_ENSURE_SUCCESS(rv, false);
+
+  rv = icon->Append(u"VisualElements"_ns);
+  NS_ENSURE_SUCCESS(rv, false);
+
+  rv = icon->Append(u"VisualElements_70.png"_ns);
+  NS_ENSURE_SUCCESS(rv, false);
+
+  nsAutoString iconPath;
+  rv = icon->GetPath(iconPath);
+  NS_ENSURE_SUCCESS(rv, false);
+
+  nsCOMPtr<nsIFile> comDll;
+  rv = appdir->Clone(getter_AddRefs(comDll));
+  NS_ENSURE_SUCCESS(rv, false);
+
+  rv = comDll->Append(u"notificationserver.dll"_ns);
+  NS_ENSURE_SUCCESS(rv, false);
+
+  nsAutoString dllPath;
+  rv = comDll->GetPath(dllPath);
+  NS_ENSURE_SUCCESS(rv, false);
+
+  nsAutoHandle txn;
+  // Manipulate the registry using a transaction so that any failures are
+  // rolled back.
+  wchar_t transactionName[] = L"" MOZ_TOAST_APP_NAME L" toast registration";
+  txn.own(::CreateTransaction(nullptr, nullptr, TRANSACTION_DO_NOT_PROMOTE, 0,
+                              0, 0, transactionName));
+  NS_ENSURE_TRUE(txn.get() != INVALID_HANDLE_VALUE, false);
+
+  LSTATUS status;
+
+  auto RegisterKey = [&](const nsAString& path, nsAutoRegKey& key) {
+    HKEY rawKey;
+    status = ::RegCreateKeyTransactedW(
+        HKEY_CURRENT_USER, PromiseFlatString(path).get(), 0, nullptr,
+        REG_OPTION_NON_VOLATILE, KEY_ALL_ACCESS, nullptr, &rawKey, nullptr, txn,
+        nullptr);
+    NS_ENSURE_TRUE(status == ERROR_SUCCESS, false);
+
+    key.own(rawKey);
+    return true;
+  };
+  auto RegisterValue = [&](nsAutoRegKey& key, const nsAString& name,
+                           unsigned long type, const nsAString& data) {
+    status = ::RegSetValueExW(
+        key, PromiseFlatString(name).get(), 0, type,
+        static_cast<const BYTE*>(PromiseFlatString(data).get()),
+        (data.Length() + 1) * sizeof(wchar_t));
+
+    return status == ERROR_SUCCESS;
+  };
+
+  // clang-format off
+  /* Writes the following keys and values to the registry.
+   * HKEY_CURRENT_USER\Software\Classes\AppID\{GUID}                                                      DllSurrogate    : REG_SZ        = ""
+   *                                   \AppUserModelId\{MOZ_TOAST_APP_NAME}PortableToast-{install hash}   CustomActivator : REG_SZ        = {GUID}
+   *                                                                                                      DisplayName     : REG_EXPAND_SZ = {display name}
+   *                                                                                                      IconUri         : REG_EXPAND_SZ = {icon path}
+   *                                   \CLSID\{GUID}                                                      AppID           : REG_SZ        = {GUID}
+   *                                                \InprocServer32                                       (Default)       : REG_SZ        = {notificationserver.dll path}
+   */
+  // clang-format on
+
+  constexpr nsLiteralString classes = u"Software\\Classes\\"_ns;
+
+  nsAutoString aumid = classes + u"AppUserModelId\\"_ns + portableAumid;
+  nsAutoRegKey aumidKey;
+  NS_ENSURE_TRUE(RegisterKey(aumid, aumidKey), false);
+
+  nsAutoString guidStr;
+  {
+    DWORD bufferSizeBytes = NSID_LENGTH * sizeof(wchar_t);
+    Buffer<wchar_t> guidBuffer(bufferSizeBytes);
+    status = ::RegGetValueW(HKEY_CURRENT_USER, aumid.get(), L"CustomActivator",
+                            RRF_RT_REG_SZ, 0, guidBuffer.Elements(),
+                            &bufferSizeBytes);
+
+    CLSID unused;
+    if (status == ERROR_SUCCESS &&
+        SUCCEEDED(CLSIDFromString(guidBuffer.Elements(), &unused))) {
+      guidStr = guidBuffer.Elements();
+    } else {
+      nsIDToCString uuidString(nsID::GenerateUUID());
+      size_t len = strlen(uuidString.get());
+      MOZ_ASSERT(len == NSID_LENGTH - 1);
+      CopyASCIItoUTF16(nsDependentCSubstring(uuidString.get(), len), guidStr);
+    }
+
+    if (status == ERROR_SUCCESS) {
+      MOZ_LOG(sWASLog, LogLevel::Debug,
+              ("Existing CustomActivator guid found: '%s'",
+               NS_ConvertUTF16toUTF8(guidStr).get()));
+    } else {
+      MOZ_LOG(sWASLog, LogLevel::Debug,
+              ("New CustomActivator guid generated: '%s'",
+               NS_ConvertUTF16toUTF8(guidStr).get()));
+    }
+  }
+  NS_ENSURE_TRUE(
+      RegisterValue(aumidKey, u"CustomActivator"_ns, REG_SZ, guidStr), false);
+  nsAutoString brandName;
+  WidgetUtils::GetBrandShortName(brandName);
+  NS_ENSURE_TRUE(
+      RegisterValue(aumidKey, u"DisplayName"_ns, REG_EXPAND_SZ, brandName),
+      false);
+  NS_ENSURE_TRUE(
+      RegisterValue(aumidKey, u"IconUri"_ns, REG_EXPAND_SZ, iconPath), false);
+
+  nsAutoString appid = classes + u"AppID\\"_ns + guidStr;
+  nsAutoRegKey appidKey;
+  NS_ENSURE_TRUE(RegisterKey(appid, appidKey), false);
+  NS_ENSURE_TRUE(RegisterValue(appidKey, u"DllSurrogate"_ns, REG_SZ, u""_ns),
+                 false);
+
+  nsAutoString clsid = classes + u"CLSID\\"_ns + guidStr;
+  nsAutoRegKey clsidKey;
+  NS_ENSURE_TRUE(RegisterKey(clsid, clsidKey), false);
+  NS_ENSURE_TRUE(RegisterValue(clsidKey, u"AppID"_ns, REG_SZ, guidStr), false);
+
+  nsAutoString inproc = clsid + u"\\InprocServer32"_ns;
+  nsAutoRegKey inprocKey;
+  NS_ENSURE_TRUE(RegisterKey(inproc, inprocKey), false);
+  // Set the component's path to this DLL
+  NS_ENSURE_TRUE(RegisterValue(inprocKey, u""_ns, REG_SZ, dllPath), false);
+
+  NS_ENSURE_TRUE(::CommitTransaction(txn), false);
+
+  MOZ_LOG(
+      sWASLog, LogLevel::Debug,
+      ("Updated registration for CustomActivator value in key 'HKCU\\%s': '%s'",
+       NS_ConvertUTF16toUTF8(aumid).get(),
+       NS_ConvertUTF16toUTF8(guidStr).get()));
+  aAumid.emplace(portableAumid);
+  return true;
+}
+
+nsresult ToastNotification::BackgroundDispatch(nsIRunnable* runnable) {
+  return NS_DispatchBackgroundTask(runnable);
+}
+
+NS_IMETHODIMP
+ToastNotification::GetSuppressForScreenSharing(bool* aRetVal) {
+  *aRetVal = mSuppressForScreenSharing;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ToastNotification::SetSuppressForScreenSharing(bool aSuppress) {
+  mSuppressForScreenSharing = aSuppress;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ToastNotification::Observe(nsISupports* aSubject, const char* aTopic,
+                           const char16_t* aData) {
+  nsDependentCString topic(aTopic);
+
+  for (auto iter = mActiveHandlers.Iter(); !iter.Done(); iter.Next()) {
+    RefPtr<ToastNotificationHandler> handler = iter.UserData();
+
+    auto removeNotification = [&]() {
+      // The handlers' destructors will do the right thing (de-register with
+      // Windows).
+      iter.Remove();
+
+      // Break the cycle between the handler and the MSCOM notification so the
+      // handler's destructor will be called.
+      handler->UnregisterHandler();
+    };
+
+    if (topic == "last-pb-context-exited"_ns) {
+      if (handler->IsPrivate()) {
+        handler->HideAlert();
+        removeNotification();
+      }
+    } else if (topic == "quit-application"_ns) {
+      removeNotification();
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ToastNotification::ShowAlertNotification(
+    const nsAString& aImageUrl, const nsAString& aAlertTitle,
+    const nsAString& aAlertText, bool aAlertTextClickable,
+    const nsAString& aAlertCookie, nsIObserver* aAlertListener,
+    const nsAString& aAlertName, const nsAString& aBidi, const nsAString& aLang,
+    const nsAString& aData, nsIPrincipal* aPrincipal, bool aInPrivateBrowsing,
+    bool aRequireInteraction) {
+  nsCOMPtr<nsIAlertNotification> alert =
+      do_CreateInstance(ALERT_NOTIFICATION_CONTRACTID);
+  if (NS_WARN_IF(!alert)) {
+    return NS_ERROR_FAILURE;
+  }
+  // vibrate is unused for now
+  nsTArray<uint32_t> vibrate;
+  nsresult rv = alert->Init(aAlertName, aImageUrl, aAlertTitle, aAlertText,
+                            aAlertTextClickable, aAlertCookie, aBidi, aLang,
+                            aData, aPrincipal, aInPrivateBrowsing,
+                            aRequireInteraction, false, vibrate);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  return ShowAlert(alert, aAlertListener);
+}
+
+NS_IMETHODIMP
+ToastNotification::ShowPersistentNotification(const nsAString& aPersistentData,
+                                              nsIAlertNotification* aAlert,
+                                              nsIObserver* aAlertListener) {
+  return ShowAlert(aAlert, aAlertListener);
+}
+
+NS_IMETHODIMP
+ToastNotification::SetManualDoNotDisturb(bool aDoNotDisturb) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+ToastNotification::GetManualDoNotDisturb(bool* aRet) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+ToastNotification::ShowAlert(nsIAlertNotification* aAlert,
+                             nsIObserver* aAlertListener) {
+  NS_ENSURE_ARG(aAlert);
+
+  if (mSuppressForScreenSharing) {
+    return NS_OK;
+  }
+
+  nsAutoString cookie;
+  MOZ_TRY(aAlert->GetCookie(cookie));
+
+  nsAutoString name;
+  MOZ_TRY(aAlert->GetName(name));
+
+  nsAutoString title;
+  MOZ_TRY(aAlert->GetTitle(title));
+  if (!EnsureUTF16Validity(title)) {
+    MOZ_LOG(sWASLog, LogLevel::Warning,
+            ("Notification title was invalid UTF16, unpaired surrogates have "
+             "been replaced."));
+  }
+
+  nsAutoString text;
+  MOZ_TRY(aAlert->GetText(text));
+  if (!EnsureUTF16Validity(text)) {
+    MOZ_LOG(sWASLog, LogLevel::Warning,
+            ("Notification text was invalid UTF16, unpaired surrogates have "
+             "been replaced."));
+  }
+
+  bool textClickable;
+  MOZ_TRY(aAlert->GetTextClickable(&textClickable));
+
+  bool isSilent;
+  MOZ_TRY(aAlert->GetSilent(&isSilent));
+
+  nsAutoString hostPort;
+  MOZ_TRY(aAlert->GetSource(hostPort));
+
+  nsAutoString opaqueRelaunchData;
+  MOZ_TRY(aAlert->GetOpaqueRelaunchData(opaqueRelaunchData));
+
+  bool requireInteraction;
+  MOZ_TRY(aAlert->GetRequireInteraction(&requireInteraction));
+
+  bool inPrivateBrowsing;
+  MOZ_TRY(aAlert->GetInPrivateBrowsing(&inPrivateBrowsing));
+
+  nsTArray<RefPtr<nsIAlertAction>> actions;
+  MOZ_TRY(aAlert->GetActions(actions));
+
+  nsCOMPtr<nsIPrincipal> principal;
+  MOZ_TRY(aAlert->GetPrincipal(getter_AddRefs(principal)));
+  bool isSystemPrincipal = principal && principal->IsSystemPrincipal();
+
+  bool handleActions = false;
+  auto imagePlacement = ImagePlacement::eInline;
+  if (isSystemPrincipal) {
+    nsCOMPtr<nsIWindowsAlertNotification> winAlert(do_QueryInterface(aAlert));
+    if (winAlert) {
+      MOZ_TRY(winAlert->GetHandleActions(&handleActions));
+
+      nsIWindowsAlertNotification::ImagePlacement placement;
+      MOZ_TRY(winAlert->GetImagePlacement(&placement));
+      switch (placement) {
+        case nsIWindowsAlertNotification::eHero:
+          imagePlacement = ImagePlacement::eHero;
+          break;
+        case nsIWindowsAlertNotification::eIcon:
+          imagePlacement = ImagePlacement::eIcon;
+          break;
+        case nsIWindowsAlertNotification::eInline:
+          imagePlacement = ImagePlacement::eInline;
+          break;
+        default:
+          MOZ_LOG(sWASLog, LogLevel::Error,
+                  ("Invalid image placement enum value: %hhu", placement));
+          return NS_ERROR_UNEXPECTED;
+      }
+    }
+  }
+
+  RefPtr<ToastNotificationHandler> oldHandler = mActiveHandlers.Get(name);
+
+  NS_ENSURE_TRUE(mAumid.isSome(), NS_ERROR_UNEXPECTED);
+  RefPtr<ToastNotificationHandler> handler = new ToastNotificationHandler(
+      this, mAumid.ref(), aAlertListener, name, cookie, title, text, hostPort,
+      textClickable, requireInteraction, actions, isSystemPrincipal,
+      opaqueRelaunchData, inPrivateBrowsing, isSilent, handleActions,
+      imagePlacement);
+  mActiveHandlers.InsertOrUpdate(name, RefPtr{handler});
+
+  MOZ_LOG(sWASLog, LogLevel::Debug,
+          ("Adding handler '%s': [%p] (now %d handlers)",
+           NS_ConvertUTF16toUTF8(name).get(), handler.get(),
+           mActiveHandlers.Count()));
+
+  nsresult rv = handler->InitAlertAsync(aAlert);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    MOZ_LOG(sWASLog, LogLevel::Debug,
+            ("Failed to init alert, removing '%s'",
+             NS_ConvertUTF16toUTF8(name).get()));
+    mActiveHandlers.Remove(name);
+    handler->UnregisterHandler();
+    return rv;
+  }
+
+  // If there was a previous handler with the same name then unregister it.
+  if (oldHandler) {
+    oldHandler->UnregisterHandler();
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ToastNotification::GetXmlStringForWindowsAlert(nsIAlertNotification* aAlert,
+                                               const nsAString& aWindowsTag,
+                                               nsAString& aString) {
+  NS_ENSURE_ARG(aAlert);
+
+  nsAutoString cookie;
+  MOZ_TRY(aAlert->GetCookie(cookie));
+
+  nsAutoString name;
+  MOZ_TRY(aAlert->GetName(name));
+
+  nsAutoString title;
+  MOZ_TRY(aAlert->GetTitle(title));
+
+  nsAutoString text;
+  MOZ_TRY(aAlert->GetText(text));
+
+  bool textClickable;
+  MOZ_TRY(aAlert->GetTextClickable(&textClickable));
+
+  bool isSilent;
+  MOZ_TRY(aAlert->GetSilent(&isSilent));
+
+  nsAutoString hostPort;
+  MOZ_TRY(aAlert->GetSource(hostPort));
+
+  nsAutoString opaqueRelaunchData;
+  MOZ_TRY(aAlert->GetOpaqueRelaunchData(opaqueRelaunchData));
+
+  bool requireInteraction;
+  MOZ_TRY(aAlert->GetRequireInteraction(&requireInteraction));
+
+  bool inPrivateBrowsing;
+  MOZ_TRY(aAlert->GetInPrivateBrowsing(&inPrivateBrowsing));
+
+  nsTArray<RefPtr<nsIAlertAction>> actions;
+  MOZ_TRY(aAlert->GetActions(actions));
+
+  nsCOMPtr<nsIPrincipal> principal;
+  MOZ_TRY(aAlert->GetPrincipal(getter_AddRefs(principal)));
+  bool isSystemPrincipal = principal && principal->IsSystemPrincipal();
+
+  NS_ENSURE_TRUE(mAumid.isSome(), NS_ERROR_UNEXPECTED);
+  RefPtr<ToastNotificationHandler> handler = new ToastNotificationHandler(
+      this, mAumid.ref(), nullptr /* aAlertListener */, name, cookie, title,
+      text, hostPort, textClickable, requireInteraction, actions,
+      isSystemPrincipal, opaqueRelaunchData, inPrivateBrowsing, isSilent);
+
+  // Usually, this will be empty during testing, making test output
+  // deterministic.
+  MOZ_TRY(handler->SetWindowsTag(aWindowsTag));
+
+  nsAutoString imageURL;
+  MOZ_TRY(aAlert->GetImageURL(imageURL));
+
+  return handler->CreateToastXmlString(imageURL, aString);
+}
+
+// Verifies that the tag recieved associates to a notification created during
+// this application's session, or handles fallback behavior.
+RefPtr<ToastHandledPromise> ToastNotification::VerifyTagPresentOrFallback(
+    const nsAString& aWindowsTag) {
+  MOZ_LOG(sWASLog, LogLevel::Debug,
+          ("Iterating %d handlers", mActiveHandlers.Count()));
+
+  for (auto iter = mActiveHandlers.Iter(); !iter.Done(); iter.Next()) {
+    RefPtr<ToastNotificationHandler> handler = iter.UserData();
+    nsAutoString tag;
+    nsresult rv = handler->GetWindowsTag(tag);
+
+    if (NS_SUCCEEDED(rv)) {
+      MOZ_LOG(sWASLog, LogLevel::Debug,
+              ("Comparing external windowsTag '%s' to handled windowsTag '%s'",
+               NS_ConvertUTF16toUTF8(aWindowsTag).get(),
+               NS_ConvertUTF16toUTF8(tag).get()));
+      if (aWindowsTag.Equals(tag)) {
+        MOZ_LOG(sWASLog, LogLevel::Debug,
+                ("External windowsTag '%s' is handled by handler [%p]",
+                 NS_ConvertUTF16toUTF8(aWindowsTag).get(), handler.get()));
+        return ToastHandledPromise::CreateAndResolve(true, __func__);
+      }
+    } else {
+      MOZ_LOG(sWASLog, LogLevel::Debug,
+              ("Failed to get windowsTag for handler [%p]", handler.get()));
+    }
+  }
+
+  // Fallback handling is required.
+
+  MOZ_LOG(sWASLog, LogLevel::Debug,
+          ("External windowsTag '%s' is not handled",
+           NS_ConvertUTF16toUTF8(aWindowsTag).get()));
+
+  RefPtr<ToastHandledPromise::Private> fallbackPromise =
+      new ToastHandledPromise::Private(__func__);
+
+  // TODO: Bug 1806005 - At time of writing this function is called in a call
+  // stack containing `WndProc` callback on an STA thread. As a result attempts
+  // to create a `ToastNotificationManager` instance results an an
+  // `RPC_E_CANTCALLOUT_ININPUTSYNCCALL` error. We can simplify the the XPCOM
+  // interface and synchronize the COM interactions if notification fallback
+  // handling were no longer handled in a `WndProc` context.
+  NS_DispatchBackgroundTask(NS_NewRunnableFunction(
+      "VerifyTagPresentOrFallback fallback background task",
+      [fallbackPromise]() { fallbackPromise->Resolve(false, __func__); }));
+
+  return fallbackPromise;
+}
+
+// Send our window's PID to the notification server so that it can grant us
+// `SetForegroundWindow` permissions. PID 0 is sent to signal no window PID.
+// Absense of PID which may occur when we are yet unable to retrieve the
+// window during startup, which is not a problem in practice as new windows
+// receive focus by default.
+void ToastNotification::SignalComNotificationHandled(
+    const nsAString& aWindowsTag) {
+  DWORD pid = 0;
+
+  nsCOMPtr<nsIWindowMediator> winMediator(
+      do_GetService(NS_WINDOWMEDIATOR_CONTRACTID));
+  if (winMediator) {
+    nsCOMPtr<mozIDOMWindowProxy> navWin;
+    winMediator->GetMostRecentWindow(u"navigator:browser",
+                                     getter_AddRefs(navWin));
+    if (navWin) {
+      nsCOMPtr<nsIWidget> widget =
+          WidgetUtils::DOMWindowToWidget(nsPIDOMWindowOuter::From(navWin));
+      if (widget) {
+        HWND hwnd = (HWND)widget->GetNativeData(NS_NATIVE_WINDOW);
+        GetWindowThreadProcessId(hwnd, &pid);
+      } else {
+        MOZ_LOG(sWASLog, LogLevel::Debug, ("Failed to get widget"));
+      }
+    } else {
+      MOZ_LOG(sWASLog, LogLevel::Debug, ("Failed to get navWin"));
+    }
+  } else {
+    MOZ_LOG(sWASLog, LogLevel::Debug, ("Failed to get WinMediator"));
+  }
+
+  // Run pipe communication off the main thread to prevent UI jank from
+  // blocking. Nothing relies on the COM server's response or that it has
+  // responded at time of commit.
+  NS_DispatchBackgroundTask(
+      NS_NewRunnableFunction(
+          "SignalComNotificationHandled background task",
+          [pid, aWindowsTag = nsString{aWindowsTag}]() mutable {
+            std::wstring pipeName = GetNotificationPipeName(aWindowsTag.get());
+
+            nsAutoHandle pipe;
+            pipe.own(CreateFileW(pipeName.c_str(), GENERIC_READ | GENERIC_WRITE,
+                                 0, nullptr, OPEN_EXISTING,
+                                 FILE_FLAG_OVERLAPPED, nullptr));
+            if (pipe.get() == INVALID_HANDLE_VALUE) {
+              MOZ_LOG(sWASLog, LogLevel::Error,
+                      ("Unable to open notification server pipe."));
+              return;
+            }
+
+            DWORD pipeFlags = PIPE_READMODE_MESSAGE;
+            if (!SetNamedPipeHandleState(pipe.get(), &pipeFlags, nullptr,
+                                         nullptr)) {
+              MOZ_LOG(sWASLog, LogLevel::Error,
+                      ("Error setting pipe handle state, error %lu",
+                       GetLastError()));
+              return;
+            }
+
+            // Pass our window's PID to the COM server receive
+            // `SetForegroundWindow` permissions, and wait for a message
+            // acknowledging the permission has been granted.
+            ToastNotificationPidMessage in{};
+            in.pid = pid;
+            ToastNotificationPermissionMessage out{};
+            auto transact = [&](OVERLAPPED& overlapped) {
+              return TransactNamedPipe(pipe.get(), &in, sizeof(in), &out,
+                                       sizeof(out), nullptr, &overlapped);
+            };
+            bool result =
+                SyncDoOverlappedIOWithTimeout(pipe, sizeof(out), transact);
+
+            if (result && out.setForegroundPermissionGranted && pid != 0) {
+              MOZ_LOG(
+                  sWASLog, LogLevel::Info,
+                  ("SetForegroundWindow permission granted to our window."));
+            } else {
+              MOZ_LOG(sWASLog, LogLevel::Error,
+                      ("SetForegroundWindow permission not granted to our "
+                       "window."));
+            }
+          }),
+      NS_DISPATCH_EVENT_MAY_BLOCK);
+}
+
+NS_IMETHODIMP
+ToastNotification::HandleWindowsTag(const nsAString& aWindowsTag,
+                                    JSContext* aCx, dom::Promise** aPromise) {
+  NS_ENSURE_TRUE(mAumid.isSome(), NS_ERROR_UNEXPECTED);
+  NS_ENSURE_TRUE(NS_IsMainThread(), NS_ERROR_NOT_SAME_THREAD);
+
+  ErrorResult rv;
+  RefPtr<dom::Promise> promise =
+      dom::Promise::Create(xpc::CurrentNativeGlobal(aCx), rv);
+  ENSURE_SUCCESS(rv, rv.StealNSResult());
+
+  this->VerifyTagPresentOrFallback(aWindowsTag)
+      ->Then(
+          GetMainThreadSerialEventTarget(), __func__,
+          [aWindowsTag = nsString(aWindowsTag),
+           promise](const bool aTagWasHandled) {
+            // We no longer need to query toast information from OS and can
+            // allow the COM server to proceed (toast information is lost once
+            // the COM server's `Activate` callback returns).
+            SignalComNotificationHandled(aWindowsTag);
+
+            dom::AutoJSAPI js;
+            if (NS_WARN_IF(!js.Init(promise->GetGlobalObject()))) {
+              promise->MaybeReject(NS_ERROR_FAILURE);
+              return;
+            }
+
+            // Resolve the DOM Promise with a JS object. Set properties if
+            // fallback handling is necessary.
+
+            JSContext* cx = js.cx();
+            JS::Rooted<JSObject*> obj(cx, JS_NewPlainObject(cx));
+
+            JS::Rooted<JS::Value> attVal(cx, JS::BooleanValue(aTagWasHandled));
+            Unused << NS_WARN_IF(
+                !JS_SetProperty(cx, obj, "tagWasHandled", attVal));
+
+            promise->MaybeResolve(obj);
+          },
+          [aWindowsTag = nsString(aWindowsTag), promise]() {
+            // We no longer need to query toast information from OS and can
+            // allow the COM server to proceed (toast information is lost once
+            // the COM server's `Activate` callback returns).
+            SignalComNotificationHandled(aWindowsTag);
+
+            promise->MaybeReject(NS_ERROR_FAILURE);
+          });
+
+  promise.forget(aPromise);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ToastNotification::CloseAlert(const nsAString& aAlertName,
+                              bool aContextClosed) {
+  RefPtr<ToastNotificationHandler> handler;
+  if (NS_WARN_IF(!mActiveHandlers.Get(aAlertName, getter_AddRefs(handler)))) {
+    return NS_OK;
+  }
+
+  if (!aContextClosed || handler->IsPrivate()) {
+    // Hide the alert when not implicitly closed by tab/window closing or when
+    // notification originated from a private tab.
+    handler->HideAlert();
+  }
+
+  mActiveHandlers.Remove(aAlertName);
+  handler->UnregisterHandler();
+
+  return NS_OK;
+}
+
+bool ToastNotification::IsActiveHandler(const nsAString& aAlertName,
+                                        ToastNotificationHandler* aHandler) {
+  RefPtr<ToastNotificationHandler> handler;
+  if (NS_WARN_IF(!mActiveHandlers.Get(aAlertName, getter_AddRefs(handler)))) {
+    return false;
+  }
+  return handler == aHandler;
+}
+
+void ToastNotification::RemoveHandler(const nsAString& aAlertName,
+                                      ToastNotificationHandler* aHandler) {
+  // The alert may have been replaced; only remove it from the active
+  // handler's map if it's the same.
+  if (IsActiveHandler(aAlertName, aHandler)) {
+    // Terrible things happen if the destructor of a handler is called inside
+    // the hashtable .Remove() method. Wait until we have returned from there.
+    RefPtr<ToastNotificationHandler> kungFuDeathGrip(aHandler);
+    mActiveHandlers.Remove(aAlertName);
+    aHandler->UnregisterHandler();
+  }
+}
+
+NS_IMETHODIMP
+ToastNotification::RemoveAllNotificationsForInstall() {
+  HRESULT hr = S_OK;
+
+  ComPtr<IToastNotificationManagerStatics> manager;
+  hr = GetActivationFactory(
+      HStringReference(
+          RuntimeClass_Windows_UI_Notifications_ToastNotificationManager)
+          .Get(),
+      &manager);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), NS_ERROR_FAILURE);
+
+  HString aumid;
+  MOZ_ASSERT(mAumid.isSome());
+  hr = aumid.Set(mAumid.ref().get());
+  NS_ENSURE_TRUE(SUCCEEDED(hr), NS_ERROR_FAILURE);
+
+  // Hide toasts in action center.
+  [&]() {
+    ComPtr<IToastNotificationManagerStatics2> manager2;
+    hr = manager.As(&manager2);
+    NS_ENSURE_TRUE_VOID(SUCCEEDED(hr));
+
+    ComPtr<IToastNotificationHistory> history;
+    hr = manager2->get_History(&history);
+    NS_ENSURE_TRUE_VOID(SUCCEEDED(hr));
+
+    hr = history->ClearWithId(aumid.Get());
+    NS_ENSURE_TRUE_VOID(SUCCEEDED(hr));
+  }();
+
+  // Hide scheduled toasts.
+  [&]() {
+    ComPtr<IToastNotifier> notifier;
+    hr = manager->CreateToastNotifierWithId(aumid.Get(), &notifier);
+    NS_ENSURE_TRUE_VOID(SUCCEEDED(hr));
+
+    ComPtr<IVectorView_ScheduledToastNotification> scheduledToasts;
+    hr = notifier->GetScheduledToastNotifications(&scheduledToasts);
+    NS_ENSURE_TRUE_VOID(SUCCEEDED(hr));
+
+    unsigned int schedSize;
+    hr = scheduledToasts->get_Size(&schedSize);
+    NS_ENSURE_TRUE_VOID(SUCCEEDED(hr));
+
+    for (unsigned int i = 0; i < schedSize; i++) {
+      ComPtr<IScheduledToastNotification> schedToast;
+      hr = scheduledToasts->GetAt(i, &schedToast);
+      if (NS_WARN_IF(FAILED(hr))) {
+        continue;
+      }
+
+      hr = notifier->RemoveFromSchedule(schedToast.Get());
+      Unused << NS_WARN_IF(FAILED(hr));
+    }
+  }();
+
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(WindowsAlertNotification, AlertNotification,
+                            nsIWindowsAlertNotification)
+
+NS_IMETHODIMP
+WindowsAlertNotification::GetHandleActions(bool* aHandleActions) {
+  *aHandleActions = mHandleActions;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WindowsAlertNotification::SetHandleActions(bool aHandleActions) {
+  mHandleActions = aHandleActions;
+  return NS_OK;
+}
+
+NS_IMETHODIMP WindowsAlertNotification::GetImagePlacement(
+    nsIWindowsAlertNotification::ImagePlacement* aImagePlacement) {
+  *aImagePlacement = mImagePlacement;
+  return NS_OK;
+}
+
+NS_IMETHODIMP WindowsAlertNotification::SetImagePlacement(
+    nsIWindowsAlertNotification::ImagePlacement aImagePlacement) {
+  switch (aImagePlacement) {
+    case eHero:
+    case eIcon:
+    case eInline:
+      mImagePlacement = aImagePlacement;
+      break;
+    default:
+      MOZ_LOG(sWASLog, LogLevel::Error,
+              ("Invalid image placement enum value: %hhu", aImagePlacement));
+      return NS_ERROR_INVALID_ARG;
+  }
+
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/ToastNotification.h b/widget/windows/ToastNotification.h
new file mode 100644
index 0000000000..9beb08cc27
--- /dev/null
+++ b/widget/windows/ToastNotification.h
@@ -0,0 +1,83 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ToastNotification_h__
+#define ToastNotification_h__
+
+#include "mozilla/Maybe.h"
+#include "mozilla/MozPromise.h"
+#include "nsIAlertsService.h"
+#include "nsIObserver.h"
+#include "nsIThread.h"
+#include "nsIWindowsAlertsService.h"
+#include "nsRefPtrHashtable.h"
+#include "mozilla/AlertNotification.h"
+
+namespace mozilla {
+namespace widget {
+
+using ToastHandledPromise = MozPromise<bool, bool, true>;
+
+class ToastNotificationHandler;
+
+class WindowsAlertNotification final : public AlertNotification,
+                                       public nsIWindowsAlertNotification {
+ public:
+  NS_DECL_NSIWINDOWSALERTNOTIFICATION
+  NS_FORWARD_NSIALERTNOTIFICATION(AlertNotification::)
+  NS_DECL_ISUPPORTS_INHERITED
+
+  WindowsAlertNotification() = default;
+
+ protected:
+  virtual ~WindowsAlertNotification() = default;
+  bool mHandleActions = false;
+  nsIWindowsAlertNotification::ImagePlacement mImagePlacement = eInline;
+};
+
+class ToastNotification final : public nsIWindowsAlertsService,
+                                public nsIAlertsDoNotDisturb,
+                                public nsIObserver {
+ public:
+  NS_DECL_NSIALERTSSERVICE
+  NS_DECL_NSIWINDOWSALERTSSERVICE
+  NS_DECL_NSIALERTSDONOTDISTURB
+  NS_DECL_NSIOBSERVER
+  NS_DECL_ISUPPORTS
+
+  ToastNotification();
+
+  nsresult Init();
+
+  bool IsActiveHandler(const nsAString& aAlertName,
+                       ToastNotificationHandler* aHandler);
+  void RemoveHandler(const nsAString& aAlertName,
+                     ToastNotificationHandler* aHandler);
+
+  nsresult BackgroundDispatch(nsIRunnable* runnable);
+
+ protected:
+  virtual ~ToastNotification();
+  bool EnsureAumidRegistered();
+
+  static bool AssignIfMsixAumid(Maybe<nsAutoString>& aAumid);
+  static bool AssignIfNsisAumid(nsAutoString& aInstallHash,
+                                Maybe<nsAutoString>& aAumid);
+  static bool RegisterRuntimeAumid(nsAutoString& aInstallHash,
+                                   Maybe<nsAutoString>& aAumid);
+
+  RefPtr<ToastHandledPromise> VerifyTagPresentOrFallback(
+      const nsAString& aWindowsTag);
+  static void SignalComNotificationHandled(const nsAString& aWindowsTag);
+
+  nsRefPtrHashtable<nsStringHashKey, ToastNotificationHandler> mActiveHandlers;
+  Maybe<nsAutoString> mAumid;
+  bool mSuppressForScreenSharing = false;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/windows/ToastNotificationHandler.cpp b/widget/windows/ToastNotificationHandler.cpp
new file mode 100644
index 0000000000..a493342719
--- /dev/null
+++ b/widget/windows/ToastNotificationHandler.cpp
@@ -0,0 +1,1167 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ToastNotificationHandler.h"
+
+#include <windows.foundation.h>
+
+#include "gfxUtils.h"
+#include "gfxPlatform.h"
+#include "imgIContainer.h"
+#include "imgIRequest.h"
+#include "json/json.h"
+#include "mozilla/gfx/2D.h"
+#ifdef MOZ_BACKGROUNDTASKS
+#  include "mozilla/BackgroundTasks.h"
+#endif
+#include "mozilla/HashFunctions.h"
+#include "mozilla/JSONStringWriteFuncs.h"
+#include "mozilla/Result.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Tokenizer.h"
+#include "mozilla/Unused.h"
+#include "mozilla/WindowsVersion.h"
+#include "mozilla/intl/Localization.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsAppRunner.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
+#include "nsIDUtils.h"
+#include "nsIStringBundle.h"
+#include "nsIToolkitProfile.h"
+#include "nsIToolkitProfileService.h"
+#include "nsIURI.h"
+#include "nsIWidget.h"
+#include "nsIWindowMediator.h"
+#include "nsNetUtil.h"
+#include "nsPIDOMWindow.h"
+#include "nsProxyRelease.h"
+#include "nsXREDirProvider.h"
+#include "ToastNotificationHeaderOnlyUtils.h"
+#include "WidgetUtils.h"
+#include "WinUtils.h"
+
+#include "ToastNotification.h"
+
+namespace mozilla {
+namespace widget {
+
+extern LazyLogModule sWASLog;
+
+using namespace ABI::Windows::Data::Xml::Dom;
+using namespace ABI::Windows::Foundation;
+using namespace ABI::Windows::UI::Notifications;
+using namespace Microsoft::WRL;
+using namespace Microsoft::WRL::Wrappers;
+using namespace toastnotification;
+
+// Needed to disambiguate internal and Windows `ToastNotification` classes.
+using WinToastNotification = ABI::Windows::UI::Notifications::ToastNotification;
+using ToastActivationHandler =
+    ITypedEventHandler<WinToastNotification*, IInspectable*>;
+using ToastDismissedHandler =
+    ITypedEventHandler<WinToastNotification*, ToastDismissedEventArgs*>;
+using ToastFailedHandler =
+    ITypedEventHandler<WinToastNotification*, ToastFailedEventArgs*>;
+using IVectorView_ToastNotification =
+    Collections::IVectorView<WinToastNotification*>;
+
+NS_IMPL_ISUPPORTS(ToastNotificationHandler, nsIAlertNotificationImageListener)
+
+static bool SetNodeValueString(const nsString& aString, IXmlNode* node,
+                               IXmlDocument* xml) {
+  ComPtr<IXmlText> inputText;
+  HRESULT hr;
+  hr = xml->CreateTextNode(HStringReference(aString.get()).Get(), &inputText);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  ComPtr<IXmlNode> inputTextNode;
+  hr = inputText.As(&inputTextNode);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  ComPtr<IXmlNode> appendedChild;
+  hr = node->AppendChild(inputTextNode.Get(), &appendedChild);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  return true;
+}
+
+static bool SetAttribute(ComPtr<IXmlElement>& element,
+                         const HStringReference& name, const nsAString& value) {
+  HString valueStr;
+  valueStr.Set(PromiseFlatString(value).get());
+
+  HRESULT hr = element->SetAttribute(name.Get(), valueStr.Get());
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  return true;
+}
+
+static bool AddActionNode(ComPtr<IXmlDocument>& toastXml,
+                          ComPtr<IXmlNode>& actionsNode,
+                          const nsAString& actionTitle,
+                          const nsAString& launchArg,
+                          const nsAString& actionArgs,
+                          const nsAString& actionPlacement = u""_ns,
+                          const nsAString& activationType = u""_ns) {
+  ComPtr<IXmlElement> action;
+  HRESULT hr =
+      toastXml->CreateElement(HStringReference(L"action").Get(), &action);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  bool success =
+      SetAttribute(action, HStringReference(L"content"), actionTitle);
+  NS_ENSURE_TRUE(success, false);
+
+  // Action arguments overwrite the toast's launch arguments, so we need to
+  // prepend the launch arguments necessary for the Notification Server to
+  // reconstruct the toast's origin.
+  //
+  // Web Notification actions are arbitrary strings; to prevent breaking launch
+  // argument parsing the action argument must be last. All delimiters after
+  // `action` are part of the action arugment.
+  nsAutoString args = launchArg + u"\n"_ns +
+                      nsDependentString(kLaunchArgAction) + u"\n"_ns +
+                      actionArgs;
+  success = SetAttribute(action, HStringReference(L"arguments"), args);
+  NS_ENSURE_TRUE(success, false);
+
+  if (!actionPlacement.IsEmpty()) {
+    success =
+        SetAttribute(action, HStringReference(L"placement"), actionPlacement);
+    NS_ENSURE_TRUE(success, false);
+  }
+
+  if (!activationType.IsEmpty()) {
+    success = SetAttribute(action, HStringReference(L"activationType"),
+                           activationType);
+    NS_ENSURE_TRUE(success, false);
+
+    // No special argument handling: when `activationType="system"`, `arguments`
+    // should be a Windows-specific keyword, namely "dismiss" or "snooze", which
+    // are supposed to make a system handled dismiss/snooze buttons.
+    // https://learn.microsoft.com/en-us/windows/apps/design/shell/tiles-and-notifications/adaptive-interactive-toasts?tabs=xml#snoozedismiss
+    //
+    // Note that while using it prevents calling our notification COM server,
+    // it somehow still calls OnActivate instead of OnDismiss. Thus, we still
+    // need to handle such callbacks manually by checking `arguments`.
+    success = SetAttribute(action, HStringReference(L"arguments"), actionArgs);
+    NS_ENSURE_TRUE(success, false);
+  }
+
+  // Add <action> to <actions>
+  ComPtr<IXmlNode> actionNode;
+  hr = action.As(&actionNode);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  ComPtr<IXmlNode> appendedChild;
+  hr = actionsNode->AppendChild(actionNode.Get(), &appendedChild);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  return true;
+}
+
+nsresult ToastNotificationHandler::GetWindowsTag(nsAString& aWindowsTag) {
+  aWindowsTag.Assign(mWindowsTag);
+  return NS_OK;
+}
+
+nsresult ToastNotificationHandler::SetWindowsTag(const nsAString& aWindowsTag) {
+  mWindowsTag.Assign(aWindowsTag);
+  return NS_OK;
+}
+
+// clang - format off
+/* Populate the launch argument so the COM server can reconstruct the toast
+ * origin.
+ *
+ *   program
+ *   {MOZ_APP_NAME}
+ *   profile
+ *   {path to profile}
+ */
+// clang-format on
+Result<nsString, nsresult> ToastNotificationHandler::GetLaunchArgument() {
+  nsString launchArg;
+
+  // When the preference is false, the COM notification server will be invoked,
+  // discover that there is no `program`, and exit (successfully), after which
+  // Windows will invoke the in-product Windows 8-style callbacks.  When true,
+  // the COM notification server will launch Firefox with sufficient arguments
+  // for Firefox to handle the notification.
+  if (!Preferences::GetBool(
+          "alerts.useSystemBackend.windows.notificationserver.enabled",
+          false)) {
+    // Include dummy key/value so that newline appended arguments aren't off by
+    // one line.
+    launchArg += u"invalid key\ninvalid value"_ns;
+    return launchArg;
+  }
+
+  // `program` argument.
+  launchArg += nsDependentString(kLaunchArgProgram) + u"\n"_ns MOZ_APP_NAME;
+
+  // `profile` argument.
+  nsCOMPtr<nsIFile> profDir;
+  bool wantCurrentProfile = true;
+#ifdef MOZ_BACKGROUNDTASKS
+  if (BackgroundTasks::IsBackgroundTaskMode()) {
+    // Notifications popped from a background task want to invoke Firefox with a
+    // different profile -- the default browsing profile.  We'd prefer to not
+    // specify a profile, so that the Firefox invoked by the notification server
+    // chooses its default profile, but this might pop the profile chooser in
+    // some configurations.
+    wantCurrentProfile = false;
+
+    nsCOMPtr<nsIToolkitProfileService> profileSvc =
+        do_GetService(NS_PROFILESERVICE_CONTRACTID);
+    if (profileSvc) {
+      nsCOMPtr<nsIToolkitProfile> defaultProfile;
+      nsresult rv =
+          profileSvc->GetDefaultProfile(getter_AddRefs(defaultProfile));
+      if (NS_SUCCEEDED(rv) && defaultProfile) {
+        // Not all installations have a default profile.  But if one is set,
+        // then it should have a profile directory.
+        MOZ_TRY(defaultProfile->GetRootDir(getter_AddRefs(profDir)));
+      }
+    }
+  }
+#endif
+  if (wantCurrentProfile) {
+    MOZ_TRY(NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                   getter_AddRefs(profDir)));
+  }
+
+  if (profDir) {
+    nsAutoString profilePath;
+    MOZ_TRY(profDir->GetPath(profilePath));
+    launchArg += u"\n"_ns + nsDependentString(kLaunchArgProfile) + u"\n"_ns +
+                 profilePath;
+  }
+
+  // `windowsTag` argument.
+  launchArg +=
+      u"\n"_ns + nsDependentString(kLaunchArgTag) + u"\n"_ns + mWindowsTag;
+
+  // `logging` argument.
+  if (Preferences::GetBool(
+          "alerts.useSystemBackend.windows.notificationserver.verbose",
+          false)) {
+    // Signal notification to log verbose messages.
+    launchArg +=
+        u"\n"_ns + nsDependentString(kLaunchArgLogging) + u"\nverbose"_ns;
+  }
+
+  return launchArg;
+}
+
+static ComPtr<IToastNotificationManagerStatics>
+GetToastNotificationManagerStatics() {
+  ComPtr<IToastNotificationManagerStatics> toastNotificationManagerStatics;
+  HRESULT hr = GetActivationFactory(
+      HStringReference(
+          RuntimeClass_Windows_UI_Notifications_ToastNotificationManager)
+          .Get(),
+      &toastNotificationManagerStatics);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  return toastNotificationManagerStatics;
+}
+
+ToastNotificationHandler::~ToastNotificationHandler() {
+  if (mImageRequest) {
+    mImageRequest->Cancel(NS_BINDING_ABORTED);
+    mImageRequest = nullptr;
+  }
+
+  if (mHasImage && mImageFile) {
+    DebugOnly<nsresult> rv = mImageFile->Remove(false);
+    NS_ASSERTION(NS_SUCCEEDED(rv), "Cannot remove temporary image file");
+  }
+
+  UnregisterHandler();
+}
+
+void ToastNotificationHandler::UnregisterHandler() {
+  if (mNotification) {
+    mNotification->remove_Dismissed(mDismissedToken);
+    mNotification->remove_Activated(mActivatedToken);
+    mNotification->remove_Failed(mFailedToken);
+  }
+
+  mNotification = nullptr;
+  mNotifier = nullptr;
+
+  SendFinished();
+}
+
+nsresult ToastNotificationHandler::InitAlertAsync(
+    nsIAlertNotification* aAlert) {
+  MOZ_TRY(InitWindowsTag());
+
+#ifdef MOZ_BACKGROUNDTASKS
+  nsAutoString imageUrl;
+  if (BackgroundTasks::IsBackgroundTaskMode() &&
+      NS_SUCCEEDED(aAlert->GetImageURL(imageUrl)) && !imageUrl.IsEmpty()) {
+    // Bug 1870750: Image decoding relies on gfx and runs on a thread pool,
+    // which expects to have been initialized early and on the main thread.
+    // Since background tasks run headless this never occurs. In this case we
+    // force gfx initialization.
+    Unused << NS_WARN_IF(!gfxPlatform::GetPlatform());
+  }
+#endif
+
+  return aAlert->LoadImage(/* aTimeout = */ 0, this, /* aUserData = */ nullptr,
+                           getter_AddRefs(mImageRequest));
+}
+
+// Uniquely identify this toast to Windows.  Existing names and cookies are not
+// suitable: we want something generated and unique.  This is needed to check if
+// toast is still present in the Windows Action Center when we receive a dismiss
+// timeout.
+//
+// Local testing reveals that the space of tags is not global but instead is per
+// AUMID.  Since an installation uses a unique AUMID incorporating the install
+// directory hash, it should not witness another installation's tag.
+nsresult ToastNotificationHandler::InitWindowsTag() {
+  mWindowsTag.Truncate();
+
+  nsAutoString tag;
+
+  // Multiple profiles might overwrite each other's toast messages when a
+  // common name is used for a given host port. We prevent this by including
+  // the profile directory as part of the toast hash.
+  nsCOMPtr<nsIFile> profDir;
+  MOZ_TRY(NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                 getter_AddRefs(profDir)));
+  MOZ_TRY(profDir->GetPath(tag));
+
+  if (!mHostPort.IsEmpty()) {
+    // Notification originated from a web notification.
+    // `mName` will be in the form `{mHostPort}#tag:{tag}` if the notification
+    // was created with a tag and `{mHostPort}#notag:{uuid}` otherwise.
+    tag += mName;
+  } else {
+    // Notification originated from the browser chrome.
+    if (!mName.IsEmpty()) {
+      tag += u"chrome#tag:"_ns;
+      // Browser chrome notifications don't follow any convention for naming.
+      tag += mName;
+    } else {
+      // No associated name, append a UUID to prevent reuse of the same tag.
+      nsIDToCString uuidString(nsID::GenerateUUID());
+      size_t len = strlen(uuidString.get());
+      MOZ_ASSERT(len == NSID_LENGTH - 1);
+      nsAutoString uuid;
+      CopyASCIItoUTF16(nsDependentCSubstring(uuidString.get(), len), uuid);
+
+      tag += u"chrome#notag:"_ns;
+      tag += uuid;
+    }
+  }
+
+  // Windows notification tags are limited to 16 characters, or 64 characters
+  // after the Creators Update; therefore we hash the tag to fit the minimum
+  // range.
+  HashNumber hash = HashString(tag);
+  mWindowsTag.AppendPrintf("%010u", hash);
+
+  return NS_OK;
+}
+
+nsString ToastNotificationHandler::ActionArgsJSONString(
+    const nsString& aAction, const nsString& aOpaqueRelaunchData = u""_ns) {
+  nsAutoCString actionArgsData;
+
+  JSONStringRefWriteFunc js(actionArgsData);
+  JSONWriter w(js, JSONWriter::SingleLineStyle);
+  w.Start();
+
+  w.StringProperty("action", NS_ConvertUTF16toUTF8(aAction));
+
+  if (mIsSystemPrincipal) {
+    // Privileged/chrome alerts (not activated by Windows) can have custom
+    // relaunch data.
+    if (!aOpaqueRelaunchData.IsEmpty()) {
+      w.StringProperty("opaqueRelaunchData",
+                       NS_ConvertUTF16toUTF8(aOpaqueRelaunchData));
+    }
+
+    // Privileged alerts include any provided name for metrics.
+    if (!mName.IsEmpty()) {
+      w.StringProperty("privilegedName", NS_ConvertUTF16toUTF8(mName));
+    }
+  } else {
+    if (!mHostPort.IsEmpty()) {
+      w.StringProperty("launchUrl", NS_ConvertUTF16toUTF8(mHostPort));
+    }
+  }
+
+  w.End();
+
+  return NS_ConvertUTF8toUTF16(actionArgsData);
+}
+
+ComPtr<IXmlDocument> ToastNotificationHandler::CreateToastXmlDocument() {
+  ComPtr<IToastNotificationManagerStatics> toastNotificationManagerStatics =
+      GetToastNotificationManagerStatics();
+  NS_ENSURE_TRUE(toastNotificationManagerStatics, nullptr);
+
+  ToastTemplateType toastTemplate;
+  if (mHostPort.IsEmpty()) {
+    toastTemplate =
+        mHasImage ? ToastTemplateType::ToastTemplateType_ToastImageAndText03
+                  : ToastTemplateType::ToastTemplateType_ToastText03;
+  } else {
+    toastTemplate =
+        mHasImage ? ToastTemplateType::ToastTemplateType_ToastImageAndText04
+                  : ToastTemplateType::ToastTemplateType_ToastText04;
+  }
+
+  ComPtr<IXmlDocument> toastXml;
+  toastNotificationManagerStatics->GetTemplateContent(toastTemplate, &toastXml);
+
+  if (!toastXml) {
+    return nullptr;
+  }
+
+  nsresult ns;
+  HRESULT hr;
+  bool success;
+
+  if (mHasImage) {
+    ComPtr<IXmlNodeList> toastImageElements;
+    hr = toastXml->GetElementsByTagName(HStringReference(L"image").Get(),
+                                        &toastImageElements);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+    ComPtr<IXmlNode> imageNode;
+    hr = toastImageElements->Item(0, &imageNode);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+    ComPtr<IXmlElement> image;
+    hr = imageNode.As(&image);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+    success = SetAttribute(image, HStringReference(L"src"), mImageUri);
+    NS_ENSURE_TRUE(success, nullptr);
+
+    switch (mImagePlacement) {
+      case ImagePlacement::eHero:
+        success =
+            SetAttribute(image, HStringReference(L"placement"), u"hero"_ns);
+        NS_ENSURE_TRUE(success, nullptr);
+        break;
+      case ImagePlacement::eIcon:
+        success = SetAttribute(image, HStringReference(L"placement"),
+                               u"appLogoOverride"_ns);
+        NS_ENSURE_TRUE(success, nullptr);
+        break;
+      case ImagePlacement::eInline:
+        // No attribute placement attribute for inline images.
+        break;
+    }
+  }
+
+  ComPtr<IXmlNodeList> toastTextElements;
+  hr = toastXml->GetElementsByTagName(HStringReference(L"text").Get(),
+                                      &toastTextElements);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  ComPtr<IXmlNode> titleTextNodeRoot;
+  hr = toastTextElements->Item(0, &titleTextNodeRoot);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  ComPtr<IXmlNode> msgTextNodeRoot;
+  hr = toastTextElements->Item(1, &msgTextNodeRoot);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  success = SetNodeValueString(mTitle, titleTextNodeRoot.Get(), toastXml.Get());
+  NS_ENSURE_TRUE(success, nullptr);
+
+  success = SetNodeValueString(mMsg, msgTextNodeRoot.Get(), toastXml.Get());
+  NS_ENSURE_TRUE(success, nullptr);
+
+  ComPtr<IXmlNodeList> toastElements;
+  hr = toastXml->GetElementsByTagName(HStringReference(L"toast").Get(),
+                                      &toastElements);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  ComPtr<IXmlNode> toastNodeRoot;
+  hr = toastElements->Item(0, &toastNodeRoot);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  ComPtr<IXmlElement> toastElement;
+  hr = toastNodeRoot.As(&toastElement);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  if (mRequireInteraction) {
+    success = SetAttribute(toastElement, HStringReference(L"scenario"),
+                           u"reminder"_ns);
+    NS_ENSURE_TRUE(success, nullptr);
+  }
+
+  auto maybeLaunchArg = GetLaunchArgument();
+  NS_ENSURE_TRUE(maybeLaunchArg.isOk(), nullptr);
+  nsString launchArg = maybeLaunchArg.unwrap();
+
+  nsString launchArgWithoutAction = launchArg;
+
+  if (!mIsSystemPrincipal) {
+    // Unprivileged/content alerts can't have custom relaunch data.
+    NS_WARNING_ASSERTION(mOpaqueRelaunchData.IsEmpty(),
+                         "unprivileged/content alert "
+                         "should have trivial `mOpaqueRelaunchData`");
+  }
+
+  launchArg += u"\n"_ns + nsDependentString(kLaunchArgAction) + u"\n"_ns +
+               ActionArgsJSONString(u""_ns, mOpaqueRelaunchData);
+
+  success = SetAttribute(toastElement, HStringReference(L"launch"), launchArg);
+  NS_ENSURE_TRUE(success, nullptr);
+
+  MOZ_LOG(sWASLog, LogLevel::Debug,
+          ("launchArg: '%s'", NS_ConvertUTF16toUTF8(launchArg).get()));
+
+  // Use newer toast layout for system (chrome-privileged) toasts. This gains us
+  // UI elements such as new image placement options (default image placement is
+  // larger and inline) and buttons.
+  if (mIsSystemPrincipal) {
+    ComPtr<IXmlNodeList> bindingElements;
+    hr = toastXml->GetElementsByTagName(HStringReference(L"binding").Get(),
+                                        &bindingElements);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+    ComPtr<IXmlNode> bindingNodeRoot;
+    hr = bindingElements->Item(0, &bindingNodeRoot);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+    ComPtr<IXmlElement> bindingElement;
+    hr = bindingNodeRoot.As(&bindingElement);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+    success = SetAttribute(bindingElement, HStringReference(L"template"),
+                           u"ToastGeneric"_ns);
+    NS_ENSURE_TRUE(success, nullptr);
+  }
+
+  ComPtr<IXmlElement> actions;
+  hr = toastXml->CreateElement(HStringReference(L"actions").Get(), &actions);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  ComPtr<IXmlNode> actionsNode;
+  hr = actions.As(&actionsNode);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  nsCOMPtr<nsIStringBundleService> sbs =
+      do_GetService(NS_STRINGBUNDLE_CONTRACTID);
+  NS_ENSURE_TRUE(sbs, nullptr);
+
+  nsCOMPtr<nsIStringBundle> bundle;
+  sbs->CreateBundle("chrome://alerts/locale/alert.properties",
+                    getter_AddRefs(bundle));
+  NS_ENSURE_TRUE(bundle, nullptr);
+
+  if (!mHostPort.IsEmpty()) {
+    AutoTArray<nsString, 1> formatStrings = {mHostPort};
+
+    ComPtr<IXmlNode> urlTextNodeRoot;
+    hr = toastTextElements->Item(2, &urlTextNodeRoot);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+    nsAutoString urlReference;
+    bundle->FormatStringFromName("source.label", formatStrings, urlReference);
+
+    success =
+        SetNodeValueString(urlReference, urlTextNodeRoot.Get(), toastXml.Get());
+    NS_ENSURE_TRUE(success, nullptr);
+
+    if (IsWin10AnniversaryUpdateOrLater()) {
+      ComPtr<IXmlElement> placementText;
+      hr = urlTextNodeRoot.As(&placementText);
+      if (SUCCEEDED(hr)) {
+        // placement is supported on Windows 10 Anniversary Update or later
+        SetAttribute(placementText, HStringReference(L"placement"),
+                     u"attribution"_ns);
+      }
+    }
+
+    nsAutoString disableButtonTitle;
+    ns = bundle->FormatStringFromName("webActions.disableForOrigin.label",
+                                      formatStrings, disableButtonTitle);
+    NS_ENSURE_SUCCESS(ns, nullptr);
+
+    AddActionNode(toastXml, actionsNode, disableButtonTitle,
+                  // TODO: launch into `about:preferences`?
+                  launchArgWithoutAction, ActionArgsJSONString(u"snooze"_ns),
+                  u"contextmenu"_ns);
+  }
+
+  bool wantSettings = true;
+#ifdef MOZ_BACKGROUNDTASKS
+  if (BackgroundTasks::IsBackgroundTaskMode()) {
+    // Notifications popped from a background task want to invoke Firefox with a
+    // different profile -- the default browsing profile.  Don't link to Firefox
+    // settings in some different profile: the relevant Firefox settings won't
+    // take effect.
+    wantSettings = false;
+  }
+#endif
+  if (MOZ_LIKELY(wantSettings)) {
+    nsAutoString settingsButtonTitle;
+    bundle->GetStringFromName("webActions.settings.label", settingsButtonTitle);
+    success = AddActionNode(
+        toastXml, actionsNode, settingsButtonTitle, launchArgWithoutAction,
+        // TODO: launch into `about:preferences`?
+        ActionArgsJSONString(u"settings"_ns), u"contextmenu"_ns);
+    NS_ENSURE_TRUE(success, nullptr);
+  }
+
+  for (const auto& action : mActions) {
+    // Bug 1778596: include per-action icon from image URL.
+    nsString title;
+    ns = action->GetTitle(title);
+    NS_ENSURE_SUCCESS(ns, nullptr);
+
+    nsString actionString;
+    ns = action->GetAction(actionString);
+    NS_ENSURE_SUCCESS(ns, nullptr);
+
+    nsString opaqueRelaunchData;
+    ns = action->GetOpaqueRelaunchData(opaqueRelaunchData);
+    NS_ENSURE_SUCCESS(ns, nullptr);
+
+    MOZ_LOG(sWASLog, LogLevel::Debug,
+            ("launchArgWithoutAction for '%s': '%s'",
+             NS_ConvertUTF16toUTF8(actionString).get(),
+             NS_ConvertUTF16toUTF8(launchArgWithoutAction).get()));
+
+    // Privileged/chrome alerts can have actions that are activated by Windows.
+    // Recognize these actions and enable these activations.
+    bool activationType(false);
+    ns = action->GetWindowsSystemActivationType(&activationType);
+    NS_ENSURE_SUCCESS(ns, nullptr);
+
+    nsString activationTypeString(
+        (mIsSystemPrincipal && activationType) ? u"system"_ns : u""_ns);
+
+    nsString actionArgs;
+    if (mIsSystemPrincipal && activationType) {
+      // Privileged/chrome alerts that are activated by Windows can't have
+      // custom relaunch data.
+      actionArgs = actionString;
+
+      NS_WARNING_ASSERTION(opaqueRelaunchData.IsEmpty(),
+                           "action with `windowsSystemActivationType=true` "
+                           "should have trivial `opaqueRelaunchData`");
+    } else {
+      actionArgs = ActionArgsJSONString(actionString, opaqueRelaunchData);
+    }
+
+    success = AddActionNode(toastXml, actionsNode, title,
+                            /* launchArg */ launchArgWithoutAction,
+                            /* actionArgs */ actionArgs,
+                            /* actionPlacement */ u""_ns,
+                            /* activationType */ activationTypeString);
+    NS_ENSURE_TRUE(success, nullptr);
+  }
+
+  // Windows ignores scenario=reminder added by mRequiredInteraction if
+  // there's no non-contextmenu action.
+  if (mRequireInteraction && !mActions.Length()) {
+    // `activationType="system" arguments="dismiss" content=""` provides
+    // localized text from Windows, but we support more locales than Windows
+    // does, so let's have our own.
+    nsTArray<nsCString> resIds = {
+        "toolkit/global/alert.ftl"_ns,
+    };
+    RefPtr<intl::Localization> l10n = intl::Localization::Create(resIds, true);
+    IgnoredErrorResult rv;
+    nsAutoCString closeTitle;
+    l10n->FormatValueSync("notification-default-dismiss"_ns, {}, closeTitle,
+                          rv);
+    NS_ENSURE_TRUE(!rv.Failed(), nullptr);
+
+    NS_ENSURE_TRUE(
+        AddActionNode(toastXml, actionsNode, NS_ConvertUTF8toUTF16(closeTitle),
+                      u""_ns, u"dismiss"_ns, u""_ns, u"system"_ns),
+        nullptr);
+  }
+
+  ComPtr<IXmlNode> appendedChild;
+  hr = toastNodeRoot->AppendChild(actionsNode.Get(), &appendedChild);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  if (mIsSilent) {
+    ComPtr<IXmlNode> audioNode;
+    // Create <audio silent="true"/> for silent notifications.
+    ComPtr<IXmlElement> audio;
+    hr = toastXml->CreateElement(HStringReference(L"audio").Get(), &audio);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+    SetAttribute(audio, HStringReference(L"silent"), u"true"_ns);
+
+    hr = audio.As(&audioNode);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+    hr = toastNodeRoot->AppendChild(audioNode.Get(), &appendedChild);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+  }
+
+  return toastXml;
+}
+
+nsresult ToastNotificationHandler::CreateToastXmlString(
+    const nsAString& aImageURL, nsAString& aString) {
+  HRESULT hr;
+
+  if (!aImageURL.IsEmpty()) {
+    // For testing: don't fetch and write image to disk, just include the URL.
+    mHasImage = true;
+    mImageUri.Assign(aImageURL);
+  }
+
+  ComPtr<IXmlDocument> toastXml = CreateToastXmlDocument();
+  if (!toastXml) {
+    return NS_ERROR_FAILURE;
+  }
+
+  ComPtr<IXmlNodeSerializer> ser;
+  hr = toastXml.As(&ser);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), NS_ERROR_FAILURE);
+
+  HString data;
+  hr = ser->GetXml(data.GetAddressOf());
+  NS_ENSURE_TRUE(SUCCEEDED(hr), NS_ERROR_FAILURE);
+
+  uint32_t len = 0;
+  const wchar_t* rawData = data.GetRawBuffer(&len);
+  NS_ENSURE_TRUE(rawData, NS_ERROR_FAILURE);
+  aString.Assign(rawData, len);
+
+  return NS_OK;
+}
+
+bool ToastNotificationHandler::ShowAlert() {
+  if (!mBackend->IsActiveHandler(mName, this)) {
+    return false;
+  }
+
+  ComPtr<IXmlDocument> toastXml = CreateToastXmlDocument();
+
+  if (!toastXml) {
+    return false;
+  }
+
+  return CreateWindowsNotificationFromXml(toastXml);
+}
+
+bool ToastNotificationHandler::IsPrivate() { return mInPrivateBrowsing; }
+
+void ToastNotificationHandler::HideAlert() {
+  if (mNotifier && mNotification) {
+    mNotifier->Hide(mNotification.Get());
+  }
+}
+
+bool ToastNotificationHandler::CreateWindowsNotificationFromXml(
+    ComPtr<IXmlDocument>& aXml) {
+  ComPtr<IToastNotificationFactory> factory;
+  HRESULT hr;
+
+  hr = GetActivationFactory(
+      HStringReference(RuntimeClass_Windows_UI_Notifications_ToastNotification)
+          .Get(),
+      &factory);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  hr = factory->CreateToastNotification(aXml.Get(), &mNotification);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  RefPtr<ToastNotificationHandler> self = this;
+
+  hr = mNotification->add_Activated(
+      Callback<ToastActivationHandler>([self](IToastNotification* aNotification,
+                                              IInspectable* aInspectable) {
+        return self->OnActivate(ComPtr<IToastNotification>(aNotification),
+                                ComPtr<IInspectable>(aInspectable));
+      }).Get(),
+      &mActivatedToken);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  hr = mNotification->add_Dismissed(
+      Callback<ToastDismissedHandler>([self](IToastNotification* aNotification,
+                                             IToastDismissedEventArgs* aArgs) {
+        return self->OnDismiss(ComPtr<IToastNotification>(aNotification),
+                               ComPtr<IToastDismissedEventArgs>(aArgs));
+      }).Get(),
+      &mDismissedToken);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  hr = mNotification->add_Failed(
+      Callback<ToastFailedHandler>([self](IToastNotification* aNotification,
+                                          IToastFailedEventArgs* aArgs) {
+        return self->OnFail(ComPtr<IToastNotification>(aNotification),
+                            ComPtr<IToastFailedEventArgs>(aArgs));
+      }).Get(),
+      &mFailedToken);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  ComPtr<IToastNotification2> notification2;
+  hr = mNotification.As(&notification2);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  HString hTag;
+  hr = hTag.Set(mWindowsTag.get());
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  hr = notification2->put_Tag(hTag.Get());
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  ComPtr<IToastNotificationManagerStatics> toastNotificationManagerStatics =
+      GetToastNotificationManagerStatics();
+  NS_ENSURE_TRUE(toastNotificationManagerStatics, false);
+
+  HString aumid;
+  hr = aumid.Set(mAumid.get());
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+  hr = toastNotificationManagerStatics->CreateToastNotifierWithId(aumid.Get(),
+                                                                  &mNotifier);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  hr = mNotifier->Show(mNotification.Get());
+  NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+
+  if (mAlertListener) {
+    mAlertListener->Observe(nullptr, "alertshow", mCookie.get());
+  }
+
+  return true;
+}
+
+void ToastNotificationHandler::SendFinished() {
+  if (!mSentFinished && mAlertListener) {
+    mAlertListener->Observe(nullptr, "alertfinished", mCookie.get());
+  }
+
+  mSentFinished = true;
+}
+
+HRESULT
+ToastNotificationHandler::OnActivate(
+    const ComPtr<IToastNotification>& notification,
+    const ComPtr<IInspectable>& inspectable) {
+  MOZ_LOG(sWASLog, LogLevel::Info, ("OnActivate"));
+
+  if (mAlertListener) {
+    // Extract the `action` value from the argument string.
+    nsAutoString argumentsString;
+    nsAutoString actionString;
+    if (inspectable) {
+      ComPtr<IToastActivatedEventArgs> eventArgs;
+      HRESULT hr = inspectable.As(&eventArgs);
+      if (SUCCEEDED(hr)) {
+        HString arguments;
+        hr = eventArgs->get_Arguments(arguments.GetAddressOf());
+        if (SUCCEEDED(hr)) {
+          uint32_t len = 0;
+          const char16_t* buffer = (char16_t*)arguments.GetRawBuffer(&len);
+          if (buffer) {
+            MOZ_LOG(sWASLog, LogLevel::Info,
+                    ("OnActivate: arguments: %s",
+                     NS_ConvertUTF16toUTF8(buffer).get()));
+            argumentsString.Assign(buffer);
+
+            // Toast arguments are a newline separated key/value combination of
+            // launch arguments and an optional action argument provided as an
+            // argument to the toast's constructor. After the `action` key is
+            // found, the remainder of toast argument (including newlines) is
+            // the `action` value.
+            Tokenizer16 parse(buffer);
+            nsDependentSubstring token;
+
+            while (parse.ReadUntil(Tokenizer16::Token::NewLine(), token)) {
+              if (token == nsDependentString(kLaunchArgAction)) {
+                Unused << parse.ReadUntil(Tokenizer16::Token::EndOfFile(),
+                                          actionString);
+              } else {
+                // Next line is a value in a key/value pair, skip.
+                parse.SkipUntil(Tokenizer16::Token::NewLine());
+              }
+              // Skip newline.
+              Tokenizer16::Token unused;
+              Unused << parse.Next(unused);
+            }
+          }
+        }
+      }
+    }
+
+    if (argumentsString.EqualsLiteral("dismiss")) {
+      // XXX: Somehow Windows still fires OnActivate instead of OnDismiss for
+      // supposedly system managed dismiss button (with activationType=system
+      // and arguments=dismiss). We have to manually treat such callback as a
+      // dismiss action. For this case `arguments` only includes a keyword so we
+      // don't need to compare with a parsed result.
+      SendFinished();
+    } else if (actionString.EqualsLiteral("settings")) {
+      mAlertListener->Observe(nullptr, "alertsettingscallback", mCookie.get());
+    } else if (actionString.EqualsLiteral("snooze")) {
+      mAlertListener->Observe(nullptr, "alertdisablecallback", mCookie.get());
+    } else if (mClickable) {
+      // When clicking toast, focus moves to another process, but we want to set
+      // focus on Firefox process.
+      nsCOMPtr<nsIWindowMediator> winMediator(
+          do_GetService(NS_WINDOWMEDIATOR_CONTRACTID));
+      if (winMediator) {
+        nsCOMPtr<mozIDOMWindowProxy> navWin;
+        winMediator->GetMostRecentWindow(u"navigator:browser",
+                                         getter_AddRefs(navWin));
+        if (navWin) {
+          nsCOMPtr<nsIWidget> widget =
+              WidgetUtils::DOMWindowToWidget(nsPIDOMWindowOuter::From(navWin));
+          if (widget) {
+            SetForegroundWindow(
+                static_cast<HWND>(widget->GetNativeData(NS_NATIVE_WINDOW)));
+          }
+        }
+      }
+
+      if (mHandleActions) {
+        Json::Value jsonData;
+        Json::Reader jsonReader;
+
+        if (jsonReader.parse(NS_ConvertUTF16toUTF8(actionString).get(),
+                             jsonData, false)) {
+          char actionKey[] = "action";
+          if (jsonData.isMember(actionKey) && jsonData[actionKey].isString()) {
+            mAlertListener->Observe(
+                nullptr, "alertactioncallback",
+                NS_ConvertUTF8toUTF16(jsonData[actionKey].asCString()).get());
+          }
+        }
+      }
+
+      mAlertListener->Observe(nullptr, "alertclickcallback", mCookie.get());
+    }
+  }
+  mBackend->RemoveHandler(mName, this);
+  return S_OK;
+}
+
+// Returns `nullptr` if no such toast exists.
+/* static */ ComPtr<IToastNotification>
+ToastNotificationHandler::FindNotificationByTag(const nsAString& aWindowsTag,
+                                                const nsAString& aAumid) {
+  HRESULT hr = S_OK;
+
+  HString current_id;
+  current_id.Set(PromiseFlatString(aWindowsTag).get());
+
+  ComPtr<IToastNotificationManagerStatics> manager =
+      GetToastNotificationManagerStatics();
+  NS_ENSURE_TRUE(manager, nullptr);
+
+  ComPtr<IToastNotificationManagerStatics2> manager2;
+  hr = manager.As(&manager2);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  ComPtr<IToastNotificationHistory> history;
+  hr = manager2->get_History(&history);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+  ComPtr<IToastNotificationHistory2> history2;
+  hr = history.As(&history2);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  ComPtr<IVectorView_ToastNotification> toasts;
+  hr = history2->GetHistoryWithId(
+      HStringReference(PromiseFlatString(aAumid).get()).Get(), &toasts);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+  unsigned int hist_size;
+  hr = toasts->get_Size(&hist_size);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+  for (unsigned int i = 0; i < hist_size; i++) {
+    ComPtr<IToastNotification> hist_toast;
+    hr = toasts->GetAt(i, &hist_toast);
+    if (NS_WARN_IF(FAILED(hr))) {
+      continue;
+    }
+
+    ComPtr<IToastNotification2> hist_toast2;
+    hr = hist_toast.As(&hist_toast2);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+    HString history_id;
+    hr = hist_toast2->get_Tag(history_id.GetAddressOf());
+    NS_ENSURE_TRUE(SUCCEEDED(hr), nullptr);
+
+    // We can not directly compare IToastNotification objects; their IUnknown
+    // pointers should be equivalent but under inspection were not. Therefore we
+    // use the notification's tag instead.
+    if (current_id == history_id) {
+      return hist_toast;
+    }
+  }
+
+  return nullptr;
+}
+
+// A single toast message can receive multiple dismiss events, at most one for
+// the popup and at most one for the action center. We can't simply count
+// dismiss events as the user may have disabled either popups or action center
+// notifications, therefore we have to check if the toast remains in the history
+// (action center) to determine if the toast is fully dismissed.
+HRESULT
+ToastNotificationHandler::OnDismiss(
+    const ComPtr<IToastNotification>& notification,
+    const ComPtr<IToastDismissedEventArgs>& aArgs) {
+  ComPtr<IToastNotification2> notification2;
+  HRESULT hr = notification.As(&notification2);
+  NS_ENSURE_TRUE(SUCCEEDED(hr), E_FAIL);
+
+  HString tagHString;
+  hr = notification2->get_Tag(tagHString.GetAddressOf());
+  NS_ENSURE_TRUE(SUCCEEDED(hr), E_FAIL);
+
+  unsigned int len;
+  const wchar_t* tagPtr = tagHString.GetRawBuffer(&len);
+  nsAutoString tag(tagPtr, len);
+
+  if (FindNotificationByTag(tag, mAumid)) {
+    return S_OK;
+  }
+
+  SendFinished();
+  mBackend->RemoveHandler(mName, this);
+  return S_OK;
+}
+
+HRESULT
+ToastNotificationHandler::OnFail(const ComPtr<IToastNotification>& notification,
+                                 const ComPtr<IToastFailedEventArgs>& aArgs) {
+  HRESULT err;
+  aArgs->get_ErrorCode(&err);
+  MOZ_LOG(sWASLog, LogLevel::Error,
+          ("Error creating notification, error: %ld", err));
+
+  if (mHandleActions) {
+    mAlertListener->Observe(nullptr, "alerterror", mCookie.get());
+  }
+
+  SendFinished();
+  mBackend->RemoveHandler(mName, this);
+  return S_OK;
+}
+
+nsresult ToastNotificationHandler::TryShowAlert() {
+  if (NS_WARN_IF(!ShowAlert())) {
+    mBackend->RemoveHandler(mName, this);
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ToastNotificationHandler::OnImageMissing(nsISupports*) {
+  return TryShowAlert();
+}
+
+NS_IMETHODIMP
+ToastNotificationHandler::OnImageReady(nsISupports*, imgIRequest* aRequest) {
+  nsresult rv = AsyncSaveImage(aRequest);
+  if (NS_FAILED(rv)) {
+    return TryShowAlert();
+  }
+  return rv;
+}
+
+nsresult ToastNotificationHandler::AsyncSaveImage(imgIRequest* aRequest) {
+  nsresult rv =
+      NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(mImageFile));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = mImageFile->Append(u"notificationimages"_ns);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = mImageFile->Create(nsIFile::DIRECTORY_TYPE, 0500);
+  if (NS_FAILED(rv) && rv != NS_ERROR_FILE_ALREADY_EXISTS) {
+    return rv;
+  }
+
+  nsID uuid;
+  rv = nsID::GenerateUUIDInPlace(uuid);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  NSID_TrimBracketsASCII uuidStr(uuid);
+  uuidStr.AppendLiteral(".png");
+  mImageFile->AppendNative(uuidStr);
+
+  nsCOMPtr<imgIContainer> imgContainer;
+  rv = aRequest->GetImage(getter_AddRefs(imgContainer));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsMainThreadPtrHandle<ToastNotificationHandler> self(
+      new nsMainThreadPtrHolder<ToastNotificationHandler>(
+          "ToastNotificationHandler", this));
+
+  nsCOMPtr<nsIFile> imageFile(mImageFile);
+  RefPtr<mozilla::gfx::SourceSurface> surface = imgContainer->GetFrame(
+      imgIContainer::FRAME_FIRST,
+      imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
+  nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
+      "ToastNotificationHandler::AsyncWriteImage",
+      [self, imageFile, surface]() -> void {
+        nsresult rv = NS_ERROR_FAILURE;
+        if (surface) {
+          FILE* file = nullptr;
+          rv = imageFile->OpenANSIFileDesc("wb", &file);
+          if (NS_SUCCEEDED(rv)) {
+            rv = gfxUtils::EncodeSourceSurface(surface, ImageType::PNG, u""_ns,
+                                               gfxUtils::eBinaryEncode, file);
+            fclose(file);
+          }
+        }
+
+        nsCOMPtr<nsIRunnable> cbRunnable = NS_NewRunnableFunction(
+            "ToastNotificationHandler::AsyncWriteImageCb",
+            [self, rv]() -> void {
+              auto handler = const_cast<ToastNotificationHandler*>(self.get());
+              handler->OnWriteImageFinished(rv);
+            });
+
+        NS_DispatchToMainThread(cbRunnable);
+      });
+
+  return mBackend->BackgroundDispatch(r);
+}
+
+void ToastNotificationHandler::OnWriteImageFinished(nsresult rv) {
+  if (NS_SUCCEEDED(rv)) {
+    OnWriteImageSuccess();
+  }
+  TryShowAlert();
+}
+
+nsresult ToastNotificationHandler::OnWriteImageSuccess() {
+  nsresult rv;
+
+  nsCOMPtr<nsIURI> fileURI;
+  rv = NS_NewFileURI(getter_AddRefs(fileURI), mImageFile);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoCString uriStr;
+  rv = fileURI->GetSpec(uriStr);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  AppendUTF8toUTF16(uriStr, mImageUri);
+
+  mHasImage = true;
+
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/ToastNotificationHandler.h b/widget/windows/ToastNotificationHandler.h
new file mode 100644
index 0000000000..b3be34709c
--- /dev/null
+++ b/widget/windows/ToastNotificationHandler.h
@@ -0,0 +1,162 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef ToastNotificationHandler_h__
+#define ToastNotificationHandler_h__
+
+#include <windows.ui.notifications.h>
+#include <windows.data.xml.dom.h>
+#include <wrl.h>
+#include "nsCOMPtr.h"
+#include "nsICancelable.h"
+#include "nsIFile.h"
+#include "nsIWindowsAlertsService.h"
+#include "nsString.h"
+#include "mozilla/Result.h"
+
+namespace mozilla {
+namespace widget {
+
+enum class ImagePlacement {
+  eInline,
+  eHero,
+  eIcon,
+};
+
+class ToastNotification;
+
+class ToastNotificationHandler final
+    : public nsIAlertNotificationImageListener {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIALERTNOTIFICATIONIMAGELISTENER
+
+  ToastNotificationHandler(
+      ToastNotification* backend, const nsAString& aumid,
+      nsIObserver* aAlertListener, const nsAString& aName,
+      const nsAString& aCookie, const nsAString& aTitle, const nsAString& aMsg,
+      const nsAString& aHostPort, bool aClickable, bool aRequireInteraction,
+      const nsTArray<RefPtr<nsIAlertAction>>& aActions, bool aIsSystemPrincipal,
+      const nsAString& aOpaqueRelaunchData, bool aInPrivateBrowsing,
+      bool aIsSilent, bool aHandlesActions = false,
+      ImagePlacement aImagePlacement = ImagePlacement::eInline)
+      : mBackend(backend),
+        mAumid(aumid),
+        mHasImage(false),
+        mAlertListener(aAlertListener),
+        mName(aName),
+        mCookie(aCookie),
+        mTitle(aTitle),
+        mMsg(aMsg),
+        mHostPort(aHostPort),
+        mClickable(aClickable),
+        mRequireInteraction(aRequireInteraction),
+        mInPrivateBrowsing(aInPrivateBrowsing),
+        mActions(aActions.Clone()),
+        mIsSystemPrincipal(aIsSystemPrincipal),
+        mOpaqueRelaunchData(aOpaqueRelaunchData),
+        mIsSilent(aIsSilent),
+        mSentFinished(!aAlertListener),
+        mHandleActions(aHandlesActions),
+        mImagePlacement(aImagePlacement) {}
+
+  nsresult InitAlertAsync(nsIAlertNotification* aAlert);
+
+  void OnWriteImageFinished(nsresult rv);
+
+  void HideAlert();
+  bool IsPrivate();
+
+  void UnregisterHandler();
+
+  nsString ActionArgsJSONString(
+      const nsString& aAction,
+      const nsString& aOpaqueRelaunchData /* = u""_ns */);
+  nsresult CreateToastXmlString(const nsAString& aImageURL, nsAString& aString);
+
+  nsresult GetWindowsTag(nsAString& aWindowsTag);
+  nsresult SetWindowsTag(const nsAString& aWindowsTag);
+
+  // Exposed for consumption by `ToastNotification.cpp`.
+  static nsresult FindNotificationDataForWindowsTag(
+      const nsAString& aWindowsTag, const nsAString& aAumid, bool& aFoundTag,
+      nsAString& aNotificationData);
+
+ protected:
+  virtual ~ToastNotificationHandler();
+
+  using IXmlDocument = ABI::Windows::Data::Xml::Dom::IXmlDocument;
+  using IToastNotifier = ABI::Windows::UI::Notifications::IToastNotifier;
+  using IToastNotification =
+      ABI::Windows::UI::Notifications::IToastNotification;
+  using IToastDismissedEventArgs =
+      ABI::Windows::UI::Notifications::IToastDismissedEventArgs;
+  using IToastFailedEventArgs =
+      ABI::Windows::UI::Notifications::IToastFailedEventArgs;
+  using ToastTemplateType = ABI::Windows::UI::Notifications::ToastTemplateType;
+  template <typename T>
+  using ComPtr = Microsoft::WRL::ComPtr<T>;
+
+  Result<nsString, nsresult> GetLaunchArgument();
+
+  ComPtr<IToastNotification> mNotification;
+  ComPtr<IToastNotifier> mNotifier;
+
+  RefPtr<ToastNotification> mBackend;
+
+  nsString mAumid;
+  nsString mWindowsTag;
+
+  nsCOMPtr<nsICancelable> mImageRequest;
+  nsCOMPtr<nsIFile> mImageFile;
+  nsString mImageUri;
+  bool mHasImage;
+
+  EventRegistrationToken mActivatedToken;
+  EventRegistrationToken mDismissedToken;
+  EventRegistrationToken mFailedToken;
+
+  nsCOMPtr<nsIObserver> mAlertListener;
+  nsString mName;
+  nsString mCookie;
+  nsString mTitle;
+  nsString mMsg;
+  nsString mHostPort;
+  bool mClickable;
+  bool mRequireInteraction;
+  bool mInPrivateBrowsing;
+  nsTArray<RefPtr<nsIAlertAction>> mActions;
+  bool mIsSystemPrincipal;
+  nsString mOpaqueRelaunchData;
+  bool mIsSilent;
+  bool mSentFinished;
+  bool mHandleActions;
+  ImagePlacement mImagePlacement;
+
+  nsresult TryShowAlert();
+  bool ShowAlert();
+  nsresult AsyncSaveImage(imgIRequest* aRequest);
+  nsresult OnWriteImageSuccess();
+  void SendFinished();
+
+  nsresult InitWindowsTag();
+  bool CreateWindowsNotificationFromXml(ComPtr<IXmlDocument>& aToastXml);
+  ComPtr<IXmlDocument> CreateToastXmlDocument();
+
+  HRESULT OnActivate(const ComPtr<IToastNotification>& notification,
+                     const ComPtr<IInspectable>& inspectable);
+  HRESULT OnDismiss(const ComPtr<IToastNotification>& notification,
+                    const ComPtr<IToastDismissedEventArgs>& aArgs);
+  HRESULT OnFail(const ComPtr<IToastNotification>& notification,
+                 const ComPtr<IToastFailedEventArgs>& aArgs);
+
+  static ComPtr<IToastNotification> FindNotificationByTag(
+      const nsAString& aWindowsTag, const nsAString& aAumid);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif
diff --git a/widget/windows/ToastNotificationHeaderOnlyUtils.h b/widget/windows/ToastNotificationHeaderOnlyUtils.h
new file mode 100644
index 0000000000..dd777c0c32
--- /dev/null
+++ b/widget/windows/ToastNotificationHeaderOnlyUtils.h
@@ -0,0 +1,155 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ToastNotificationHeaderOnlyUtils_h
+#define mozilla_ToastNotificationHeaderOnlyUtils_h
+
+/**
+ * This header is intended for self-contained, header-only, utility code to
+ * share between Windows toast notification code in firefox.exe and
+ * notificationserver.dll.
+ */
+
+// Use XPCOM logging if we're in a XUL context, otherwise use Windows Event
+// logging.
+// NOTE: The `printf` `format` equivalent argument to `NOTIFY_LOG` is converted
+// to a wide string when outside of a XUL context. String format specifiers need
+// to specify they're a wide string with `%ls` or narrow string with `%hs`.
+#include "mozilla/Logging.h"
+#ifdef IMPL_LIBXUL
+namespace mozilla::widget {
+extern LazyLogModule sWASLog;
+}  // namespace mozilla::widget
+#  define NOTIFY_LOG(_level, _args) \
+    MOZ_LOG(mozilla::widget::sWASLog, _level, _args)
+#else
+#  include "mozilla/WindowsEventLog.h"
+
+bool gVerbose = false;
+
+#  define NOTIFY_LOG(_level, _args)                       \
+    if (gVerbose || _level == mozilla::LogLevel::Error) { \
+      POST_EXPAND_NOTIFY_LOG(MOZ_LOG_EXPAND_ARGS _args);  \
+    }
+#  define POST_EXPAND_NOTIFY_LOG(...) \
+    MOZ_WIN_EVENT_LOG_ERROR_MESSAGE(  \
+        L"" MOZ_APP_DISPLAYNAME " Notification Server", L"" __VA_ARGS__)
+#endif
+
+#include <functional>
+#include <string>
+
+#include "nsWindowsHelpers.h"
+
+namespace mozilla::widget::toastnotification {
+
+const wchar_t kLaunchArgProgram[] = L"program";
+const wchar_t kLaunchArgProfile[] = L"profile";
+const wchar_t kLaunchArgTag[] = L"windowsTag";
+const wchar_t kLaunchArgLogging[] = L"logging";
+const wchar_t kLaunchArgAction[] = L"action";
+
+const DWORD kNotificationServerTimeoutMs = (10 * 1000);
+
+struct ToastNotificationPidMessage {
+  DWORD pid = 0;
+};
+
+struct ToastNotificationPermissionMessage {
+  DWORD setForegroundPermissionGranted = 0;
+};
+
+inline std::wstring GetNotificationPipeName(const wchar_t* aTag) {
+  // Prefix required by pipe API.
+  std::wstring pipeName(LR"(\\.\pipe\)");
+
+  pipeName += L"" MOZ_APP_NAME;
+  pipeName += aTag;
+
+  return pipeName;
+}
+
+inline bool WaitEventWithTimeout(const HANDLE& event) {
+  DWORD result = WaitForSingleObject(event, kNotificationServerTimeoutMs);
+
+  switch (result) {
+    case WAIT_OBJECT_0:
+      NOTIFY_LOG(LogLevel::Info, ("Pipe wait signaled"));
+      return true;
+    case WAIT_TIMEOUT:
+      NOTIFY_LOG(LogLevel::Warning, ("Pipe wait timed out"));
+      return false;
+    case WAIT_FAILED:
+      NOTIFY_LOG(LogLevel::Error,
+                 ("Pipe wait failed, error %lu", GetLastError()));
+      return false;
+    case WAIT_ABANDONED:
+      NOTIFY_LOG(LogLevel::Error, ("Pipe wait abandoned"));
+      return false;
+    default:
+      NOTIFY_LOG(LogLevel::Error, ("Pipe wait unknown error"));
+      return false;
+  }
+}
+
+/* Handles running overlapped transactions for a Windows pipe. This function
+ * manages lifetimes of Event and OVERLAPPED objects to ensure they are not used
+ * while an overlapped operation is pending. */
+inline bool SyncDoOverlappedIOWithTimeout(
+    const nsAutoHandle& pipe, const size_t bytesExpected,
+    const std::function<BOOL(OVERLAPPED&)>& transactPipe) {
+  nsAutoHandle event(CreateEventW(nullptr, TRUE, FALSE, nullptr));
+  if (!event) {
+    NOTIFY_LOG(
+        LogLevel::Error,
+        ("Error creating pipe transaction event, error %lu", GetLastError()));
+    return false;
+  }
+
+  OVERLAPPED overlapped{};
+  overlapped.hEvent = event.get();
+  BOOL result = transactPipe(overlapped);
+
+  if (!result && GetLastError() != ERROR_IO_PENDING) {
+    NOTIFY_LOG(LogLevel::Error,
+               ("Error reading from pipe, error %lu", GetLastError()));
+    return false;
+  }
+
+  if (!WaitEventWithTimeout(overlapped.hEvent)) {
+    NOTIFY_LOG(LogLevel::Warning, ("Pipe transaction timed out, canceling "
+                                   "(transaction may still succeed)."));
+
+    CancelIo(pipe.get());
+
+    // Transaction may still succeed before cancellation is handled; fall
+    // through to normal handling.
+  }
+
+  DWORD bytesTransferred = 0;
+  // Pipe transfer has either been signaled or cancelled by this point, so it
+  // should be safe to wait on.
+  BOOL overlappedResult =
+      GetOverlappedResult(pipe.get(), &overlapped, &bytesTransferred, TRUE);
+
+  if (!overlappedResult) {
+    NOTIFY_LOG(
+        LogLevel::Error,
+        ("Error retrieving pipe overlapped result, error %lu", GetLastError()));
+    return false;
+  } else if (bytesTransferred != bytesExpected) {
+    NOTIFY_LOG(LogLevel::Error,
+               ("%lu bytes read from pipe, but %zu bytes expected",
+                bytesTransferred, bytesExpected));
+    return false;
+  }
+
+  return true;
+}
+
+}  // namespace mozilla::widget::toastnotification
+
+#endif  // mozilla_ToastNotificationHeaderOnlyUtils_h
diff --git a/widget/windows/UrlmonHeaderOnlyUtils.h b/widget/windows/UrlmonHeaderOnlyUtils.h
new file mode 100644
index 0000000000..dd9209f78f
--- /dev/null
+++ b/widget/windows/UrlmonHeaderOnlyUtils.h
@@ -0,0 +1,76 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_UrlmonHeaderOnlyUtils_h
+#define mozilla_UrlmonHeaderOnlyUtils_h
+
+#include "mozilla/ShellHeaderOnlyUtils.h"
+
+namespace mozilla {
+
+/**
+ * We used to validate a uri with SHParseDisplayName to mitigate the Windows
+ * bug (Bug 394974).  However, Bug 1573051 revealed an issue that a fragment,
+ * a string following a hash mark (#), is dropped when we extract a string
+ * from PIDL.  This is the intended behavior of Windows.
+ *
+ * To deal with the fragment issue as well as keeping our mitigation, we
+ * decided to use CreateUri to validate a uri string, but we also keep using
+ * SHParseDisplayName as a pre-check.  This is because there are several
+ * cases where CreateUri succeeds while SHParseDisplayName fails such as
+ * a non-existent file: uri.
+ *
+ * To minimize the impact of introducing CreateUri into the validation logic,
+ * we try to mimic the logic of windows_storage!IUriToPidl (ieframe!IUriToPidl
+ * in Win7) which is executed behind SHParseDisplayName.
+ * What IUriToPidl does is:
+ *   1) If a given uri has a fragment, removes a fragment.
+ *   2) Takes an absolute uri if it's available in the given uri, otherwise
+ *      takes a raw uri.
+ *
+ * As we need to get a full uri including a fragment, this function does 2).
+ */
+inline LauncherResult<_bstr_t> UrlmonValidateUri(const wchar_t* aUri) {
+  LauncherResult<UniqueAbsolutePidl> pidlResult = ShellParseDisplayName(aUri);
+  if (pidlResult.isErr()) {
+    return pidlResult.propagateErr();
+  }
+
+  // The value of |flags| is the same value as used in ieframe!_EnsureIUri in
+  // Win7, which is called behind SHParseDisplayName.  In Win10, on the other
+  // hand, an flag 0x03000000 is also passed to CreateUri, but we don't
+  // specify it because it's undocumented and unknown.
+  constexpr DWORD flags =
+      Uri_CREATE_NO_DECODE_EXTRA_INFO | Uri_CREATE_CANONICALIZE |
+      Uri_CREATE_CRACK_UNKNOWN_SCHEMES | Uri_CREATE_PRE_PROCESS_HTML_URI |
+      Uri_CREATE_IE_SETTINGS;
+  RefPtr<IUri> uri;
+  HRESULT hr;
+  SAFECALL_URLMON_FUNC(CreateUri, aUri, flags, 0, getter_AddRefs(uri));
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  _bstr_t bstrUri;
+
+  hr = uri->GetAbsoluteUri(bstrUri.GetAddress());
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  if (hr == S_FALSE) {
+    hr = uri->GetRawUri(bstrUri.GetAddress());
+    if (FAILED(hr)) {
+      return LAUNCHER_ERROR_FROM_HRESULT(hr);
+    }
+  }
+
+  return bstrUri;
+}
+
+}  // namespace mozilla
+
+#endif  // mozilla_UrlmonHeaderOnlyUtils_h
diff --git a/widget/windows/WidgetTraceEvent.cpp b/widget/windows/WidgetTraceEvent.cpp
new file mode 100644
index 0000000000..15bb4d720c
--- /dev/null
+++ b/widget/windows/WidgetTraceEvent.cpp
@@ -0,0 +1,121 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Windows widget support for event loop instrumentation.
+ * See toolkit/xre/EventTracer.cpp for more details.
+ */
+
+#include <stdio.h>
+#include <windows.h>
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/WidgetTraceEvent.h"
+#include "nsAppShellCID.h"
+#include "nsComponentManagerUtils.h"
+#include "nsCOMPtr.h"
+#include "nsIAppShellService.h"
+#include "nsIBaseWindow.h"
+#include "nsIDocShell.h"
+#include "nsISupportsImpl.h"
+#include "nsIWidget.h"
+#include "nsIAppWindow.h"
+#include "nsServiceManagerUtils.h"
+#include "nsThreadUtils.h"
+#include "nsWindowDefs.h"
+
+namespace {
+
+// Used for signaling the background thread from the main thread.
+HANDLE sEventHandle = nullptr;
+
+// We need a runnable in order to find the hidden window on the main
+// thread.
+class HWNDGetter : public mozilla::Runnable {
+ public:
+  HWNDGetter() : Runnable("HWNDGetter"), hidden_window_hwnd(nullptr) {}
+
+  HWND hidden_window_hwnd;
+
+  NS_IMETHOD Run() override {
+    // Jump through some hoops to locate the hidden window.
+    nsCOMPtr<nsIAppShellService> appShell(
+        do_GetService(NS_APPSHELLSERVICE_CONTRACTID));
+    nsCOMPtr<nsIAppWindow> hiddenWindow;
+
+    nsresult rv = appShell->GetHiddenWindow(getter_AddRefs(hiddenWindow));
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+
+    nsCOMPtr<nsIDocShell> docShell;
+    rv = hiddenWindow->GetDocShell(getter_AddRefs(docShell));
+    if (NS_FAILED(rv) || !docShell) {
+      return rv;
+    }
+
+    nsCOMPtr<nsIBaseWindow> baseWindow(do_QueryInterface(docShell));
+
+    if (!baseWindow) return NS_ERROR_FAILURE;
+
+    nsCOMPtr<nsIWidget> widget;
+    baseWindow->GetMainWidget(getter_AddRefs(widget));
+
+    if (!widget) return NS_ERROR_FAILURE;
+
+    hidden_window_hwnd = (HWND)widget->GetNativeData(NS_NATIVE_WINDOW);
+
+    return NS_OK;
+  }
+};
+
+HWND GetHiddenWindowHWND() {
+  // Need to dispatch this to the main thread because plenty of
+  // the things it wants to access are main-thread-only.
+  RefPtr<HWNDGetter> getter = new HWNDGetter();
+  NS_DispatchAndSpinEventLoopUntilComplete(
+      "GetHiddenWindowHWND"_ns, mozilla::GetMainThreadSerialEventTarget(),
+      do_AddRef(getter));
+  return getter->hidden_window_hwnd;
+}
+
+}  // namespace
+
+namespace mozilla {
+
+bool InitWidgetTracing() {
+  sEventHandle = CreateEventW(nullptr, FALSE, FALSE, nullptr);
+  return sEventHandle != nullptr;
+}
+
+void CleanUpWidgetTracing() {
+  CloseHandle(sEventHandle);
+  sEventHandle = nullptr;
+}
+
+// This function is called from the main (UI) thread.
+void SignalTracerThread() {
+  if (sEventHandle != nullptr) SetEvent(sEventHandle);
+}
+
+// This function is called from the background tracer thread.
+bool FireAndWaitForTracerEvent() {
+  MOZ_ASSERT(sEventHandle, "Tracing not initialized!");
+
+  // First, try to find the hidden window.
+  static HWND hidden_window = nullptr;
+  if (hidden_window == nullptr) {
+    hidden_window = GetHiddenWindowHWND();
+  }
+
+  if (hidden_window == nullptr) return false;
+
+  // Post the tracer message into the hidden window's message queue,
+  // and then block until it's processed.
+  PostMessage(hidden_window, MOZ_WM_TRACE, 0, 0);
+  WaitForSingleObject(sEventHandle, INFINITE);
+  return true;
+}
+
+}  // namespace mozilla
diff --git a/widget/windows/WinCompositorWidget.cpp b/widget/windows/WinCompositorWidget.cpp
new file mode 100644
index 0000000000..15957a1c3f
--- /dev/null
+++ b/widget/windows/WinCompositorWidget.cpp
@@ -0,0 +1,105 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WinCompositorWidget.h"
+
+#include "mozilla/StaticPrefs_layers.h"
+#include "mozilla/gfx/DeviceManagerDx.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/layers/Compositor.h"
+#include "mozilla/layers/CompositorThread.h"
+#include "mozilla/webrender/RenderThread.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "nsWindow.h"
+#include "VsyncDispatcher.h"
+#include "WinCompositorWindowThread.h"
+#include "VRShMem.h"
+
+#include <ddraw.h>
+
+namespace mozilla {
+namespace widget {
+
+using namespace mozilla::gfx;
+using namespace mozilla;
+
+WinCompositorWidget::WinCompositorWidget(
+    const WinCompositorWidgetInitData& aInitData,
+    const layers::CompositorOptions& aOptions)
+    : CompositorWidget(aOptions),
+      mSetParentCompleted(false),
+      mWidgetKey(aInitData.widgetKey()),
+      mWnd(reinterpret_cast<HWND>(aInitData.hWnd())),
+      mCompositorWnds(nullptr, nullptr) {
+  MOZ_ASSERT(mWnd && ::IsWindow(mWnd));
+}
+
+WinCompositorWidget::~WinCompositorWidget() { DestroyCompositorWindow(); }
+
+uintptr_t WinCompositorWidget::GetWidgetKey() { return mWidgetKey; }
+
+void WinCompositorWidget::EnsureCompositorWindow() {
+  if (mCompositorWnds.mCompositorWnd || mCompositorWnds.mInitialParentWnd) {
+    return;
+  }
+
+  mCompositorWnds = WinCompositorWindowThread::CreateCompositorWindow();
+  UpdateCompositorWnd(mCompositorWnds.mCompositorWnd, mWnd);
+
+  MOZ_ASSERT(mCompositorWnds.mCompositorWnd);
+  MOZ_ASSERT(mCompositorWnds.mInitialParentWnd);
+}
+
+void WinCompositorWidget::DestroyCompositorWindow() {
+  if (!mCompositorWnds.mCompositorWnd && !mCompositorWnds.mInitialParentWnd) {
+    return;
+  }
+  WinCompositorWindowThread::DestroyCompositorWindow(mCompositorWnds);
+  mCompositorWnds = WinCompositorWnds(nullptr, nullptr);
+}
+
+void WinCompositorWidget::UpdateCompositorWndSizeIfNecessary() {
+  if (!mCompositorWnds.mCompositorWnd) {
+    return;
+  }
+
+  LayoutDeviceIntSize size = GetClientSize();
+  if (mLastCompositorWndSize == size) {
+    return;
+  }
+
+  // This code is racing with the compositor, which needs to reparent the
+  // compositor surface to the actual window (mWnd). To avoid racing mutations,
+  // we refuse to proceed until ::SetParent() is called in the parent process.
+  // After the ::SetParent() call, composition is scheduled in
+  // CompositorWidgetParent::UpdateCompositorWnd().
+  if (!mSetParentCompleted) {
+    // ::SetParent() is not completed yet.
+    return;
+  }
+
+  MOZ_ASSERT(mWnd == ::GetParent(mCompositorWnds.mCompositorWnd));
+
+  // Force a resize and redraw (but not a move, activate, etc.).
+  if (!::SetWindowPos(
+          mCompositorWnds.mCompositorWnd, nullptr, 0, 0, size.width,
+          size.height,
+          SWP_NOACTIVATE | SWP_NOCOPYBITS | SWP_NOOWNERZORDER | SWP_NOZORDER)) {
+    return;
+  }
+
+  mLastCompositorWndSize = size;
+}
+
+// Creates a new instance of FxROutputHandler so that this compositor widget
+// can send its output to Firefox Reality for Desktop.
+void WinCompositorWidget::RequestFxrOutput() {
+  MOZ_ASSERT(mFxrHandler == nullptr);
+
+  mFxrHandler.reset(new FxROutputHandler());
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/WinCompositorWidget.h b/widget/windows/WinCompositorWidget.h
new file mode 100644
index 0000000000..fef967380c
--- /dev/null
+++ b/widget/windows/WinCompositorWidget.h
@@ -0,0 +1,103 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_WinCompositorWidget_h
+#define widget_windows_WinCompositorWidget_h
+
+#include "CompositorWidget.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/gfx/CriticalSection.h"
+#include "mozilla/gfx/Point.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/widget/WinCompositorWindowThread.h"
+#include "FxROutputHandler.h"
+#include "nsIWidget.h"
+
+class nsWindow;
+
+namespace mozilla {
+namespace widget {
+
+class PlatformCompositorWidgetDelegate : public CompositorWidgetDelegate {
+ public:
+  // Callbacks for nsWindow.
+  virtual void EnterPresentLock() = 0;
+  virtual void LeavePresentLock() = 0;
+  virtual void OnDestroyWindow() = 0;
+  virtual bool OnWindowResize(const LayoutDeviceIntSize& aSize) = 0;
+  virtual void OnWindowModeChange(nsSizeMode aSizeMode) = 0;
+
+  // Transparency handling.
+  virtual void UpdateTransparency(TransparencyMode aMode) = 0;
+  virtual void ClearTransparentWindow() = 0;
+
+  // Deliver visibility info
+  virtual void NotifyVisibilityUpdated(nsSizeMode aSizeMode,
+                                       bool aIsFullyOccluded) = 0;
+
+  // CompositorWidgetDelegate Overrides
+
+  PlatformCompositorWidgetDelegate* AsPlatformSpecificDelegate() override {
+    return this;
+  }
+};
+
+class WinCompositorWidgetInitData;
+
+// This is the Windows-specific implementation of CompositorWidget. For
+// the most part it only requires an HWND, however it maintains extra state
+// for transparent windows, as well as for synchronizing WM_SETTEXT messages
+// with the compositor.
+class WinCompositorWidget : public CompositorWidget {
+ public:
+  WinCompositorWidget(const WinCompositorWidgetInitData& aInitData,
+                      const layers::CompositorOptions& aOptions);
+  ~WinCompositorWidget() override;
+
+  // CompositorWidget Overrides
+
+  uintptr_t GetWidgetKey() override;
+  WinCompositorWidget* AsWindows() override { return this; }
+
+  HWND GetHwnd() const {
+    return mCompositorWnds.mCompositorWnd ? mCompositorWnds.mCompositorWnd
+                                          : mWnd;
+  }
+
+  HWND GetCompositorHwnd() const { return mCompositorWnds.mCompositorWnd; }
+
+  void EnsureCompositorWindow();
+  void DestroyCompositorWindow();
+  void UpdateCompositorWndSizeIfNecessary();
+
+  void RequestFxrOutput();
+  bool HasFxrOutputHandler() const { return mFxrHandler != nullptr; }
+  FxROutputHandler* GetFxrOutputHandler() const { return mFxrHandler.get(); }
+
+  virtual nsSizeMode GetWindowSizeMode() const = 0;
+  virtual bool GetWindowIsFullyOccluded() const = 0;
+
+  virtual void UpdateCompositorWnd(const HWND aCompositorWnd,
+                                   const HWND aParentWnd) = 0;
+  virtual void SetRootLayerTreeID(const layers::LayersId& aRootLayerTreeId) = 0;
+
+ protected:
+  bool mSetParentCompleted;
+
+ private:
+  uintptr_t mWidgetKey;
+  HWND mWnd;
+
+  WinCompositorWnds mCompositorWnds;
+  LayoutDeviceIntSize mLastCompositorWndSize;
+
+  UniquePtr<FxROutputHandler> mFxrHandler;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_windows_WinCompositorWidget_h
diff --git a/widget/windows/WinCompositorWindowThread.cpp b/widget/windows/WinCompositorWindowThread.cpp
new file mode 100644
index 0000000000..3b06c098e6
--- /dev/null
+++ b/widget/windows/WinCompositorWindowThread.cpp
@@ -0,0 +1,294 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "base/platform_thread.h"
+#include "WinCompositorWindowThread.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/layers/SynchronousTask.h"
+#include "mozilla/StaticPtr.h"
+#include "transport/runnable_utils.h"
+#include "mozilla/StaticPrefs_apz.h"
+
+namespace mozilla {
+namespace widget {
+
+static StaticRefPtr<WinCompositorWindowThread> sWinCompositorWindowThread;
+
+/// A window procedure that logs when an input event is received to the gfx
+/// error log
+///
+/// This is done because this window is supposed to be WM_DISABLED, but
+/// malfunctioning software may still end up targetting this window. If that
+/// happens, it's almost-certainly a bug and should be brought to the attention
+/// of the developers that are debugging the issue.
+static LRESULT CALLBACK InputEventRejectingWindowProc(HWND window, UINT msg,
+                                                      WPARAM wparam,
+                                                      LPARAM lparam) {
+  switch (msg) {
+    case WM_LBUTTONDOWN:
+    case WM_LBUTTONUP:
+    case WM_RBUTTONDOWN:
+    case WM_RBUTTONUP:
+    case WM_MBUTTONDOWN:
+    case WM_MBUTTONUP:
+    case WM_MOUSEWHEEL:
+    case WM_MOUSEHWHEEL:
+    case WM_MOUSEMOVE:
+    case WM_KEYDOWN:
+    case WM_KEYUP:
+    case WM_SYSKEYDOWN:
+    case WM_SYSKEYUP:
+      gfxCriticalNoteOnce
+          << "The compositor window received an input event even though it's "
+             "disabled. There is likely malfunctioning "
+             "software on the user's machine.";
+
+      break;
+    default:
+      break;
+  }
+  return ::DefWindowProcW(window, msg, wparam, lparam);
+}
+
+WinCompositorWindowThread::WinCompositorWindowThread(base::Thread* aThread)
+    : mThread(aThread), mMonitor("WinCompositorWindowThread") {}
+
+/* static */
+WinCompositorWindowThread* WinCompositorWindowThread::Get() {
+  if (!sWinCompositorWindowThread ||
+      sWinCompositorWindowThread->mHasAttemptedShutdown) {
+    return nullptr;
+  }
+  return sWinCompositorWindowThread;
+}
+
+/* static */
+void WinCompositorWindowThread::Start() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  base::Thread::Options options;
+  // HWND requests ui thread.
+  options.message_loop_type = MessageLoop::TYPE_UI;
+
+  if (sWinCompositorWindowThread) {
+    // Try to reuse the thread, which involves stopping and restarting it.
+    sWinCompositorWindowThread->mThread->Stop();
+    if (sWinCompositorWindowThread->mThread->StartWithOptions(options)) {
+      // Success!
+      sWinCompositorWindowThread->mHasAttemptedShutdown = false;
+      return;
+    }
+    // Restart failed, so null out our sWinCompositorWindowThread and
+    // try again with a new thread. This will cause the old singleton
+    // instance to be deallocated, which will destroy its mThread as well.
+    sWinCompositorWindowThread = nullptr;
+  }
+
+  base::Thread* thread = new base::Thread("WinCompositor");
+  if (!thread->StartWithOptions(options)) {
+    delete thread;
+    return;
+  }
+
+  sWinCompositorWindowThread = new WinCompositorWindowThread(thread);
+}
+
+/* static */
+void WinCompositorWindowThread::ShutDown() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(sWinCompositorWindowThread);
+
+  sWinCompositorWindowThread->mHasAttemptedShutdown = true;
+
+  // Our thread could hang while we're waiting for it to stop.
+  // Since we're shutting down, that's not a critical problem.
+  // We set a reasonable amount of time to wait for shutdown,
+  // and if it succeeds within that time, we correctly stop
+  // our thread by nulling out the refptr, which will cause it
+  // to be deallocated and join the thread. If it times out,
+  // we do nothing, which means that the thread will not be
+  // joined and sWinCompositorWindowThread memory will leak.
+  CVStatus status;
+  {
+    // It's important to hold the lock before posting the
+    // runnable. This ensures that the runnable can't begin
+    // until we've started our Wait, which prevents us from
+    // Waiting on a monitor that has already been notified.
+    MonitorAutoLock lock(sWinCompositorWindowThread->mMonitor);
+
+    static const TimeDuration TIMEOUT = TimeDuration::FromSeconds(2.0);
+    RefPtr<Runnable> runnable =
+        NewRunnableMethod("WinCompositorWindowThread::ShutDownTask",
+                          sWinCompositorWindowThread.get(),
+                          &WinCompositorWindowThread::ShutDownTask);
+    Loop()->PostTask(runnable.forget());
+
+    // Monitor uses SleepConditionVariableSRW, which can have
+    // spurious wakeups which are reported as timeouts, so we
+    // check timestamps to ensure that we've waited as long we
+    // intended to. If we wake early, we don't bother calculating
+    // a precise amount for the next wait; we just wait the same
+    // amount of time. This means timeout might happen after as
+    // much as 2x the TIMEOUT time.
+    TimeStamp timeStart = TimeStamp::NowLoRes();
+    do {
+      status = sWinCompositorWindowThread->mMonitor.Wait(TIMEOUT);
+    } while ((status == CVStatus::Timeout) &&
+             ((TimeStamp::NowLoRes() - timeStart) < TIMEOUT));
+  }
+
+  if (status == CVStatus::NoTimeout) {
+    sWinCompositorWindowThread = nullptr;
+  }
+}
+
+void WinCompositorWindowThread::ShutDownTask() {
+  MonitorAutoLock lock(mMonitor);
+
+  MOZ_ASSERT(IsInCompositorWindowThread());
+  mMonitor.NotifyAll();
+}
+
+/* static */
+MessageLoop* WinCompositorWindowThread::Loop() {
+  return sWinCompositorWindowThread
+             ? sWinCompositorWindowThread->mThread->message_loop()
+             : nullptr;
+}
+
+/* static */
+bool WinCompositorWindowThread::IsInCompositorWindowThread() {
+  return sWinCompositorWindowThread &&
+         sWinCompositorWindowThread->mThread->thread_id() ==
+             PlatformThread::CurrentId();
+}
+
+const wchar_t kClassNameCompositorInitalParent[] =
+    L"MozillaCompositorInitialParentClass";
+const wchar_t kClassNameCompositor[] = L"MozillaCompositorWindowClass";
+
+ATOM g_compositor_inital_parent_window_class;
+ATOM g_compositor_window_class;
+
+// This runs on the window owner thread.
+void InitializeInitialParentWindowClass() {
+  if (g_compositor_inital_parent_window_class) {
+    return;
+  }
+
+  WNDCLASSW wc;
+  wc.style = 0;
+  wc.lpfnWndProc = ::DefWindowProcW;
+  wc.cbClsExtra = 0;
+  wc.cbWndExtra = 0;
+  wc.hInstance = GetModuleHandle(nullptr);
+  wc.hIcon = nullptr;
+  wc.hCursor = nullptr;
+  wc.hbrBackground = nullptr;
+  wc.lpszMenuName = nullptr;
+  wc.lpszClassName = kClassNameCompositorInitalParent;
+  g_compositor_inital_parent_window_class = ::RegisterClassW(&wc);
+}
+
+// This runs on the window owner thread.
+void InitializeWindowClass() {
+  if (g_compositor_window_class) {
+    return;
+  }
+
+  WNDCLASSW wc;
+  wc.style = CS_OWNDC;
+  wc.lpfnWndProc = InputEventRejectingWindowProc;
+  wc.cbClsExtra = 0;
+  wc.cbWndExtra = 0;
+  wc.hInstance = GetModuleHandle(nullptr);
+  wc.hIcon = nullptr;
+  wc.hCursor = nullptr;
+  wc.hbrBackground = nullptr;
+  wc.lpszMenuName = nullptr;
+  wc.lpszClassName = kClassNameCompositor;
+  g_compositor_window_class = ::RegisterClassW(&wc);
+}
+
+/* static */
+WinCompositorWnds WinCompositorWindowThread::CreateCompositorWindow() {
+  MOZ_ASSERT(Loop());
+
+  if (!Loop()) {
+    return WinCompositorWnds(nullptr, nullptr);
+  }
+
+  layers::SynchronousTask task("Create compositor window");
+
+  HWND initialParentWnd = nullptr;
+  HWND compositorWnd = nullptr;
+
+  RefPtr<Runnable> runnable = NS_NewRunnableFunction(
+      "WinCompositorWindowThread::CreateCompositorWindow::Runnable", [&]() {
+        layers::AutoCompleteTask complete(&task);
+
+        InitializeInitialParentWindowClass();
+        InitializeWindowClass();
+
+        // Create initial parent window.
+        // We could not directly create a compositor window with a main window
+        // as parent window, so instead create it with a temporary placeholder
+        // parent. Its parent is set as main window in UI process.
+        initialParentWnd =
+            ::CreateWindowEx(WS_EX_TOOLWINDOW, kClassNameCompositorInitalParent,
+                             nullptr, WS_POPUP | WS_DISABLED, 0, 0, 1, 1,
+                             nullptr, 0, GetModuleHandle(nullptr), 0);
+        if (!initialParentWnd) {
+          gfxCriticalNoteOnce << "Inital parent window failed "
+                              << ::GetLastError();
+          return;
+        }
+
+        DWORD extendedStyle = WS_EX_NOPARENTNOTIFY | WS_EX_NOREDIRECTIONBITMAP;
+
+        if (!StaticPrefs::apz_windows_force_disable_direct_manipulation()) {
+          extendedStyle |= WS_EX_LAYERED | WS_EX_TRANSPARENT;
+        }
+
+        compositorWnd = ::CreateWindowEx(
+            extendedStyle, kClassNameCompositor, nullptr,
+            WS_CHILDWINDOW | WS_DISABLED | WS_VISIBLE, 0, 0, 1, 1,
+            initialParentWnd, 0, GetModuleHandle(nullptr), 0);
+        if (!compositorWnd) {
+          gfxCriticalNoteOnce << "Compositor window failed "
+                              << ::GetLastError();
+        }
+      });
+
+  Loop()->PostTask(runnable.forget());
+
+  task.Wait();
+
+  return WinCompositorWnds(compositorWnd, initialParentWnd);
+}
+
+/* static */
+void WinCompositorWindowThread::DestroyCompositorWindow(
+    WinCompositorWnds aWnds) {
+  MOZ_ASSERT(aWnds.mCompositorWnd);
+  MOZ_ASSERT(aWnds.mInitialParentWnd);
+  MOZ_ASSERT(Loop());
+
+  if (!Loop()) {
+    return;
+  }
+
+  RefPtr<Runnable> runnable = NS_NewRunnableFunction(
+      "WinCompositorWidget::CreateNativeWindow::Runnable", [aWnds]() {
+        ::DestroyWindow(aWnds.mCompositorWnd);
+        ::DestroyWindow(aWnds.mInitialParentWnd);
+      });
+
+  Loop()->PostTask(runnable.forget());
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/WinCompositorWindowThread.h b/widget/windows/WinCompositorWindowThread.h
new file mode 100644
index 0000000000..372e3d91c2
--- /dev/null
+++ b/widget/windows/WinCompositorWindowThread.h
@@ -0,0 +1,67 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_WinCompositorWindowThread_h
+#define widget_windows_WinCompositorWindowThread_h
+
+#include "base/thread.h"
+#include "base/message_loop.h"
+#include "mozilla/Monitor.h"
+
+namespace mozilla {
+namespace widget {
+
+struct WinCompositorWnds {
+  HWND mCompositorWnd;
+  HWND mInitialParentWnd;
+  WinCompositorWnds(HWND aCompositorWnd, HWND aInitialParentWnd)
+      : mCompositorWnd(aCompositorWnd), mInitialParentWnd(aInitialParentWnd) {}
+};
+
+class WinCompositorWindowThread final {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING_WITH_DELETE_ON_MAIN_THREAD(
+      WinCompositorWindowThread)
+
+ public:
+  /// Can be called from any thread.
+  static WinCompositorWindowThread* Get();
+
+  /// Can only be called from the main thread.
+  static void Start();
+
+  /// Can only be called from the main thread.
+  static void ShutDown();
+
+  /// Can be called from any thread.
+  static MessageLoop* Loop();
+
+  /// Can be called from any thread.
+  static bool IsInCompositorWindowThread();
+
+  /// Can be called from any thread.
+  static WinCompositorWnds CreateCompositorWindow();
+
+  /// Can be called from any thread.
+  static void DestroyCompositorWindow(WinCompositorWnds aWnds);
+
+ private:
+  explicit WinCompositorWindowThread(base::Thread* aThread);
+  ~WinCompositorWindowThread() {}
+
+  void ShutDownTask();
+
+  UniquePtr<base::Thread> const mThread;
+  Monitor mMonitor;
+
+  // Has ShutDown been called on us? We might have survived if our thread join
+  // timed out.
+  bool mHasAttemptedShutdown = false;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_windows_WinCompositorWindowThread_h
diff --git a/widget/windows/WinEventObserver.cpp b/widget/windows/WinEventObserver.cpp
new file mode 100644
index 0000000000..7abac8a59a
--- /dev/null
+++ b/widget/windows/WinEventObserver.cpp
@@ -0,0 +1,223 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <windows.h>
+#include <winuser.h>
+#include <wtsapi32.h>
+
+#include "WinEventObserver.h"
+
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/Logging.h"
+#include "mozilla/StaticPtr.h"
+#include "nsHashtablesFwd.h"
+#include "nsdefs.h"
+
+namespace mozilla::widget {
+
+LazyLogModule gWinEventObserverLog("WinEventObserver");
+#define LOG(...) MOZ_LOG(gWinEventObserverLog, LogLevel::Info, (__VA_ARGS__))
+
+// static
+StaticRefPtr<WinEventHub> WinEventHub::sInstance;
+
+// static
+bool WinEventHub::Ensure() {
+  if (sInstance) {
+    return true;
+  }
+
+  LOG("WinEventHub::Ensure()");
+
+  RefPtr<WinEventHub> instance = new WinEventHub();
+  if (!instance->Initialize()) {
+    MOZ_ASSERT_UNREACHABLE("unexpected to be called");
+    return false;
+  }
+  sInstance = instance;
+  ClearOnShutdown(&sInstance);
+  return true;
+}
+
+WinEventHub::WinEventHub() {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG("WinEventHub::WinEventHub()");
+}
+
+WinEventHub::~WinEventHub() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mObservers.IsEmpty());
+  LOG("WinEventHub::~WinEventHub()");
+
+  if (mHWnd) {
+    ::DestroyWindow(mHWnd);
+    mHWnd = nullptr;
+  }
+}
+
+bool WinEventHub::Initialize() {
+  WNDCLASSW wc;
+  HMODULE hSelf = ::GetModuleHandle(nullptr);
+
+  if (!GetClassInfoW(hSelf, L"MozillaWinEventHubClass", &wc)) {
+    ZeroMemory(&wc, sizeof(WNDCLASSW));
+    wc.hInstance = hSelf;
+    wc.lpfnWndProc = WinEventProc;
+    wc.lpszClassName = L"MozillaWinEventHubClass";
+    RegisterClassW(&wc);
+  }
+
+  mHWnd = ::CreateWindowW(L"MozillaWinEventHubClass", L"WinEventHub", 0, 0, 0,
+                          0, 0, nullptr, nullptr, hSelf, nullptr);
+  if (!mHWnd) {
+    return false;
+  }
+
+  return true;
+}
+
+// static
+LRESULT CALLBACK WinEventHub::WinEventProc(HWND aHwnd, UINT aMsg,
+                                           WPARAM aWParam, LPARAM aLParam) {
+  if (sInstance) {
+    sInstance->ProcessWinEventProc(aHwnd, aMsg, aWParam, aLParam);
+  }
+  return ::DefWindowProc(aHwnd, aMsg, aWParam, aLParam);
+}
+
+void WinEventHub::ProcessWinEventProc(HWND aHwnd, UINT aMsg, WPARAM aWParam,
+                                      LPARAM aLParam) {
+  for (const auto& observer : mObservers) {
+    observer->OnWinEventProc(aHwnd, aMsg, aWParam, aLParam);
+  }
+}
+
+void WinEventHub::AddObserver(WinEventObserver* aObserver) {
+  LOG("WinEventHub::AddObserver() aObserver %p", aObserver);
+
+  mObservers.Insert(aObserver);
+}
+
+void WinEventHub::RemoveObserver(WinEventObserver* aObserver) {
+  LOG("WinEventHub::RemoveObserver() aObserver %p", aObserver);
+
+  mObservers.Remove(aObserver);
+}
+
+WinEventObserver::~WinEventObserver() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mDestroyed);
+}
+
+void WinEventObserver::Destroy() {
+  LOG("WinEventObserver::Destroy() this %p", this);
+
+  WinEventHub::Get()->RemoveObserver(this);
+  mDestroyed = true;
+}
+
+// static
+already_AddRefed<DisplayStatusObserver> DisplayStatusObserver::Create(
+    DisplayStatusListener* aListener) {
+  if (!WinEventHub::Ensure()) {
+    return nullptr;
+  }
+  RefPtr<DisplayStatusObserver> observer = new DisplayStatusObserver(aListener);
+  WinEventHub::Get()->AddObserver(observer);
+  return observer.forget();
+}
+
+DisplayStatusObserver::DisplayStatusObserver(DisplayStatusListener* aListener)
+    : mListener(aListener) {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG("DisplayStatusObserver::DisplayStatusObserver() this %p", this);
+
+  mDisplayStatusHandle = ::RegisterPowerSettingNotification(
+      WinEventHub::Get()->GetWnd(), &GUID_SESSION_DISPLAY_STATUS,
+      DEVICE_NOTIFY_WINDOW_HANDLE);
+}
+
+DisplayStatusObserver::~DisplayStatusObserver() {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG("DisplayStatusObserver::~DisplayStatusObserver() this %p", this);
+
+  if (mDisplayStatusHandle) {
+    ::UnregisterPowerSettingNotification(mDisplayStatusHandle);
+    mDisplayStatusHandle = nullptr;
+  }
+}
+
+void DisplayStatusObserver::OnWinEventProc(HWND aHwnd, UINT aMsg,
+                                           WPARAM aWParam, LPARAM aLParam) {
+  if (aMsg == WM_POWERBROADCAST && aWParam == PBT_POWERSETTINGCHANGE) {
+    POWERBROADCAST_SETTING* setting = (POWERBROADCAST_SETTING*)aLParam;
+    if (setting &&
+        ::IsEqualGUID(setting->PowerSetting, GUID_SESSION_DISPLAY_STATUS) &&
+        setting->DataLength == sizeof(DWORD)) {
+      bool displayOn = PowerMonitorOff !=
+                       static_cast<MONITOR_DISPLAY_STATE>(setting->Data[0]);
+
+      LOG("DisplayStatusObserver::OnWinEventProc() displayOn %d this %p",
+          displayOn, this);
+      mListener->OnDisplayStateChanged(displayOn);
+    }
+  }
+}
+
+// static
+already_AddRefed<SessionChangeObserver> SessionChangeObserver::Create(
+    SessionChangeListener* aListener) {
+  if (!WinEventHub::Ensure()) {
+    return nullptr;
+  }
+  RefPtr<SessionChangeObserver> observer = new SessionChangeObserver(aListener);
+  WinEventHub::Get()->AddObserver(observer);
+  return observer.forget();
+}
+
+SessionChangeObserver::SessionChangeObserver(SessionChangeListener* aListener)
+    : mListener(aListener) {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG("SessionChangeObserver::SessionChangeObserver() this %p", this);
+
+  auto hwnd = WinEventHub::Get()->GetWnd();
+  DebugOnly<BOOL> wtsRegistered =
+      ::WTSRegisterSessionNotification(hwnd, NOTIFY_FOR_THIS_SESSION);
+  NS_ASSERTION(wtsRegistered, "WTSRegisterSessionNotification failed!\n");
+}
+SessionChangeObserver::~SessionChangeObserver() {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG("SessionChangeObserver::~SessionChangeObserver() this %p", this);
+
+  auto hwnd = WinEventHub::Get()->GetWnd();
+  // Unregister notifications from terminal services
+  ::WTSUnRegisterSessionNotification(hwnd);
+}
+
+void SessionChangeObserver::OnWinEventProc(HWND aHwnd, UINT aMsg,
+                                           WPARAM aWParam, LPARAM aLParam) {
+  if (aMsg == WM_WTSSESSION_CHANGE &&
+      (aWParam == WTS_SESSION_LOCK || aWParam == WTS_SESSION_UNLOCK)) {
+    Maybe<bool> isCurrentSession;
+    DWORD currentSessionId = 0;
+    if (!::ProcessIdToSessionId(::GetCurrentProcessId(), &currentSessionId)) {
+      isCurrentSession = Nothing();
+    } else {
+      LOG("SessionChangeObserver::OnWinEventProc() aWParam %zu aLParam "
+          "%" PRIdLPTR
+          " "
+          "currentSessionId %lu this %p",
+          aWParam, aLParam, currentSessionId, this);
+
+      isCurrentSession = Some(static_cast<DWORD>(aLParam) == currentSessionId);
+    }
+    mListener->OnSessionChange(aWParam, isCurrentSession);
+  }
+}
+
+#undef LOG
+
+}  // namespace mozilla::widget
diff --git a/widget/windows/WinEventObserver.h b/widget/windows/WinEventObserver.h
new file mode 100644
index 0000000000..6a267871dd
--- /dev/null
+++ b/widget/windows/WinEventObserver.h
@@ -0,0 +1,115 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_WinEventObserver_h
+#define widget_windows_WinEventObserver_h
+
+#include <windows.h>
+
+#include "mozilla/Maybe.h"
+#include "nsISupportsImpl.h"
+#include "nsTHashSet.h"
+
+namespace mozilla {
+
+namespace widget {
+
+class WinEventObserver {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WinEventObserver)
+ public:
+  virtual void OnWinEventProc(HWND aHwnd, UINT aMsg, WPARAM aWParam,
+                              LPARAM aLParam) {}
+  virtual void Destroy();
+
+ protected:
+  virtual ~WinEventObserver();
+
+  bool mDestroyed = false;
+};
+
+// Uses singleton window to observe events like display status and session
+// change.
+class WinEventHub final {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WinEventHub)
+
+ public:
+  // Returns true if the singleton exists (or was created). Will return
+  // false if the singleton couldn't be created, in which case a call
+  // to Get() will return a nullptr. It is safe to call this function
+  // repeatedly.
+  static bool Ensure();
+  static RefPtr<WinEventHub> Get() { return sInstance; }
+
+  void AddObserver(WinEventObserver* aObserver);
+  void RemoveObserver(WinEventObserver* aObserver);
+
+  HWND GetWnd() { return mHWnd; }
+
+ private:
+  WinEventHub();
+  ~WinEventHub();
+
+  static LRESULT CALLBACK WinEventProc(HWND aHwnd, UINT aMsg, WPARAM aWParam,
+                                       LPARAM aLParam);
+
+  bool Initialize();
+  void ProcessWinEventProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);
+
+  HWND mHWnd = nullptr;
+  nsTHashSet<nsRefPtrHashKey<WinEventObserver>> mObservers;
+
+  static StaticRefPtr<WinEventHub> sInstance;
+};
+
+class DisplayStatusListener {
+ public:
+  virtual void OnDisplayStateChanged(bool aDisplayOn) = 0;
+};
+
+// Observe Display on/off event
+class DisplayStatusObserver final : public WinEventObserver {
+ public:
+  static already_AddRefed<DisplayStatusObserver> Create(
+      DisplayStatusListener* aListener);
+
+ private:
+  explicit DisplayStatusObserver(DisplayStatusListener* aListener);
+  virtual ~DisplayStatusObserver();
+  void OnWinEventProc(HWND aHwnd, UINT aMsg, WPARAM aWParam,
+                      LPARAM aLParam) override;
+
+  DisplayStatusListener* mListener;
+
+  HPOWERNOTIFY mDisplayStatusHandle = nullptr;
+};
+
+class SessionChangeListener {
+ public:
+  virtual void OnSessionChange(WPARAM aStatusCode,
+                               Maybe<bool> aIsCurrentSession) = 0;
+};
+
+// Observe session lock/unlock event
+class SessionChangeObserver : public WinEventObserver {
+ public:
+  static already_AddRefed<SessionChangeObserver> Create(
+      SessionChangeListener* aListener);
+
+ private:
+  explicit SessionChangeObserver(SessionChangeListener* aListener);
+  virtual ~SessionChangeObserver();
+
+  void Initialize();
+  void OnWinEventProc(HWND aHwnd, UINT aMsg, WPARAM aWParam,
+                      LPARAM aLParam) override;
+
+  SessionChangeListener* mListener;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_windows_WinEventObserver_h
diff --git a/widget/windows/WinHeaderOnlyUtils.h b/widget/windows/WinHeaderOnlyUtils.h
new file mode 100644
index 0000000000..15861cc73b
--- /dev/null
+++ b/widget/windows/WinHeaderOnlyUtils.h
@@ -0,0 +1,820 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_WinHeaderOnlyUtils_h
+#define mozilla_WinHeaderOnlyUtils_h
+
+#include <windows.h>
+#include <winerror.h>
+#include <winnt.h>
+#include <winternl.h>
+#include <objbase.h>
+#include <shlwapi.h>
+#undef ParseURL
+#include <stdlib.h>
+#include <tuple>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/DynamicallyLinkedFunctionPtr.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/ResultVariant.h"
+#include "mozilla/UniquePtr.h"
+#include "nsWindowsHelpers.h"
+
+#if defined(MOZILLA_INTERNAL_API)
+#  include "nsIFile.h"
+#  include "nsString.h"
+#endif  // defined(MOZILLA_INTERNAL_API)
+
+/**
+ * This header is intended for self-contained, header-only, utility code for
+ * Win32. It may be used outside of xul.dll, in places such as firefox.exe or
+ * mozglue.dll. If your code creates dependencies on Mozilla libraries, you
+ * should put it elsewhere.
+ */
+
+#if !defined(STATUS_SUCCESS)
+#  define STATUS_SUCCESS ((NTSTATUS)0x00000000L)
+#endif  // !defined(STATUS_SUCCESS)
+
+// Our data indicates a few users of Win7 x86 hit failure to load urlmon.dll
+// for unknown reasons.  Since we don't always require urlmon.dll on Win7,
+// we delay-load it, which causes a crash if loading urlmon.dll fails.  This
+// macro is to safely load and call urlmon's API graciously without crash.
+#if defined(_X86_)
+#  define SAFECALL_URLMON_FUNC(FuncName, ...)                                  \
+    do {                                                                       \
+      static const mozilla::StaticDynamicallyLinkedFunctionPtr<                \
+          decltype(&::FuncName)>                                               \
+          func(L"urlmon.dll", #FuncName);                                      \
+      hr =                                                                     \
+          func ? func(__VA_ARGS__) : HRESULT_FROM_WIN32(ERROR_PROC_NOT_FOUND); \
+    } while (0)
+#else
+#  define SAFECALL_URLMON_FUNC(FuncName, ...) hr = ::FuncName(__VA_ARGS__)
+#endif
+
+namespace mozilla {
+
+class WindowsError final {
+ private:
+  // HRESULT and NTSTATUS are both typedefs of LONG, so we cannot use
+  // overloading to properly differentiate between the two. Instead we'll use
+  // static functions to convert the various error types to HRESULTs before
+  // instantiating.
+  explicit constexpr WindowsError(HRESULT aHResult) : mHResult(aHResult) {}
+
+ public:
+  using UniqueString = UniquePtr<WCHAR[], LocalFreeDeleter>;
+
+  static constexpr WindowsError FromNtStatus(NTSTATUS aNtStatus) {
+    if (aNtStatus == STATUS_SUCCESS) {
+      // Special case: we don't want to set FACILITY_NT_BIT
+      // (HRESULT_FROM_NT does not handle this case, unlike HRESULT_FROM_WIN32)
+      return WindowsError(S_OK);
+    }
+
+    return WindowsError(HRESULT_FROM_NT(aNtStatus));
+  }
+
+  static constexpr WindowsError FromHResult(HRESULT aHResult) {
+    return WindowsError(aHResult);
+  }
+
+  static constexpr WindowsError FromWin32Error(DWORD aWin32Err) {
+    return WindowsError(HRESULT_FROM_WIN32(aWin32Err));
+  }
+
+  static WindowsError FromLastError() {
+    return FromWin32Error(::GetLastError());
+  }
+
+  static WindowsError CreateSuccess() { return WindowsError(S_OK); }
+
+  static WindowsError CreateGeneric() {
+    return FromWin32Error(ERROR_UNIDENTIFIED_ERROR);
+  }
+
+  bool IsSuccess() const { return SUCCEEDED(mHResult); }
+
+  bool IsFailure() const { return FAILED(mHResult); }
+
+  bool IsAvailableAsWin32Error() const {
+    return IsAvailableAsNtStatus() ||
+           HRESULT_FACILITY(mHResult) == FACILITY_WIN32;
+  }
+
+  bool IsAvailableAsNtStatus() const {
+    return mHResult == S_OK || (mHResult & FACILITY_NT_BIT);
+  }
+
+  bool IsAvailableAsHResult() const { return true; }
+
+  UniqueString AsString() const {
+    LPWSTR rawMsgBuf = nullptr;
+    constexpr DWORD flags = FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                            FORMAT_MESSAGE_FROM_SYSTEM |
+                            FORMAT_MESSAGE_IGNORE_INSERTS;
+    DWORD result =
+        ::FormatMessageW(flags, nullptr, mHResult, 0,
+                         reinterpret_cast<LPWSTR>(&rawMsgBuf), 0, nullptr);
+    if (!result) {
+      return nullptr;
+    }
+
+    return UniqueString(rawMsgBuf);
+  }
+
+  HRESULT AsHResult() const { return mHResult; }
+
+  // Not all HRESULTs are convertible to Win32 Errors, so we use Maybe
+  Maybe<DWORD> AsWin32Error() const {
+    if (mHResult == S_OK) {
+      return Some(static_cast<DWORD>(ERROR_SUCCESS));
+    }
+
+    if (HRESULT_FACILITY(mHResult) == FACILITY_WIN32) {
+      // This is the inverse of HRESULT_FROM_WIN32
+      return Some(static_cast<DWORD>(HRESULT_CODE(mHResult)));
+    }
+
+    // The NTSTATUS facility is a special case and thus does not utilize the
+    // HRESULT_FACILITY and HRESULT_CODE macros.
+    if (mHResult & FACILITY_NT_BIT) {
+      return Some(NtStatusToWin32Error(
+          static_cast<NTSTATUS>(mHResult & ~FACILITY_NT_BIT)));
+    }
+
+    return Nothing();
+  }
+
+  // Not all HRESULTs are convertible to NTSTATUS, so we use Maybe
+  Maybe<NTSTATUS> AsNtStatus() const {
+    if (mHResult == S_OK) {
+      return Some(STATUS_SUCCESS);
+    }
+
+    // The NTSTATUS facility is a special case and thus does not utilize the
+    // HRESULT_FACILITY and HRESULT_CODE macros.
+    if (mHResult & FACILITY_NT_BIT) {
+      return Some(static_cast<NTSTATUS>(mHResult & ~FACILITY_NT_BIT));
+    }
+
+    return Nothing();
+  }
+
+  constexpr bool operator==(const WindowsError& aOther) const {
+    return mHResult == aOther.mHResult;
+  }
+
+  constexpr bool operator!=(const WindowsError& aOther) const {
+    return mHResult != aOther.mHResult;
+  }
+
+  static DWORD NtStatusToWin32Error(NTSTATUS aNtStatus) {
+    static const StaticDynamicallyLinkedFunctionPtr<
+        decltype(&RtlNtStatusToDosError)>
+        pRtlNtStatusToDosError(L"ntdll.dll", "RtlNtStatusToDosError");
+
+    MOZ_ASSERT(!!pRtlNtStatusToDosError);
+    if (!pRtlNtStatusToDosError) {
+      return ERROR_UNIDENTIFIED_ERROR;
+    }
+
+    return pRtlNtStatusToDosError(aNtStatus);
+  }
+
+ private:
+  // We store the error code as an HRESULT because they can encode both Win32
+  // error codes and NTSTATUS codes.
+  HRESULT mHResult;
+};
+
+namespace detail {
+template <>
+struct UnusedZero<WindowsError> {
+  using StorageType = WindowsError;
+
+  static constexpr bool value = true;
+  static constexpr StorageType nullValue = WindowsError::FromHResult(S_OK);
+
+  static constexpr void AssertValid(StorageType aValue) {}
+  static constexpr const WindowsError& Inspect(const StorageType& aValue) {
+    return aValue;
+  }
+  static constexpr WindowsError Unwrap(StorageType aValue) { return aValue; }
+  static constexpr StorageType Store(WindowsError aValue) { return aValue; }
+};
+}  // namespace detail
+
+enum DetourResultCode : uint32_t {
+  RESULT_OK = 0,
+  INTERCEPTOR_MOD_NULL,
+  INTERCEPTOR_MOD_INACCESSIBLE,
+  INTERCEPTOR_PROC_NULL,
+  INTERCEPTOR_PROC_INACCESSIBLE,
+  DETOUR_PATCHER_RESERVE_FOR_MODULE_PE_ERROR,
+  DETOUR_PATCHER_RESERVE_FOR_MODULE_TEXT_ERROR,
+  DETOUR_PATCHER_RESERVE_FOR_MODULE_RESERVE_ERROR,
+  DETOUR_PATCHER_DO_RESERVE_ERROR,
+  DETOUR_PATCHER_NEXT_TRAMPOLINE_ERROR,
+  DETOUR_PATCHER_INVALID_TRAMPOLINE,
+  DETOUR_PATCHER_WRITE_POINTER_ERROR,
+  DETOUR_PATCHER_CREATE_TRAMPOLINE_ERROR,
+  FUNCHOOKCROSSPROCESS_COPYSTUB_ERROR,
+  MMPOLICY_RESERVE_INVALIDARG,
+  MMPOLICY_RESERVE_ZERO_RESERVATIONSIZE,
+  MMPOLICY_RESERVE_CREATEFILEMAPPING,
+  MMPOLICY_RESERVE_MAPVIEWOFFILE,
+  MMPOLICY_RESERVE_NOBOUND_RESERVE_ERROR,
+  MMPOLICY_RESERVE_FINDREGION_INVALIDLEN,
+  MMPOLICY_RESERVE_FINDREGION_INVALIDRANGE,
+  MMPOLICY_RESERVE_FINDREGION_VIRTUALQUERY_ERROR,
+  MMPOLICY_RESERVE_FINDREGION_NO_FREE_REGION,
+  MMPOLICY_RESERVE_FINAL_RESERVE_ERROR,
+};
+
+#if defined(NIGHTLY_BUILD)
+struct DetourError {
+  // We have a 16-bytes buffer, but only minimum bytes to detour per
+  // architecture are copied.  See CreateTrampoline in PatcherDetour.h.
+  DetourResultCode mErrorCode;
+  uint8_t mOrigBytes[16];
+  explicit DetourError(DetourResultCode aError)
+      : mErrorCode(aError), mOrigBytes{} {}
+  DetourError(DetourResultCode aError, DWORD aWin32Error)
+      : mErrorCode(aError), mOrigBytes{} {
+    static_assert(sizeof(mOrigBytes) >= sizeof(aWin32Error),
+                  "Can't fit a DWORD in mOrigBytes");
+    *reinterpret_cast<DWORD*>(mOrigBytes) = aWin32Error;
+  }
+  operator WindowsError() const {
+    return WindowsError::FromHResult(mErrorCode);
+  }
+};
+#endif  // defined(NIGHTLY_BUILD)
+
+template <typename T>
+using WindowsErrorResult = Result<T, WindowsError>;
+
+struct LauncherError {
+  LauncherError(const char* aFile, int aLine, WindowsError aWin32Error)
+      : mFile(aFile), mLine(aLine), mError(aWin32Error) {}
+
+#if defined(NIGHTLY_BUILD)
+  LauncherError(const char* aFile, int aLine,
+                const Maybe<DetourError>& aDetourError)
+      : mFile(aFile),
+        mLine(aLine),
+        mError(aDetourError.isSome() ? aDetourError.value()
+                                     : WindowsError::CreateGeneric()),
+        mDetourError(aDetourError) {}
+#endif  // defined(NIGHTLY_BUILD)
+
+  const char* mFile;
+  int mLine;
+  WindowsError mError;
+#if defined(NIGHTLY_BUILD)
+  Maybe<DetourError> mDetourError;
+#endif  // defined(NIGHTLY_BUILD)
+
+  bool operator==(const LauncherError& aOther) const {
+    return mError == aOther.mError;
+  }
+
+  bool operator!=(const LauncherError& aOther) const {
+    return mError != aOther.mError;
+  }
+
+  bool operator==(const WindowsError& aOther) const { return mError == aOther; }
+
+  bool operator!=(const WindowsError& aOther) const { return mError != aOther; }
+};
+
+#if defined(MOZ_USE_LAUNCHER_ERROR)
+
+template <typename T>
+using LauncherResult = Result<T, LauncherError>;
+
+template <typename T>
+using LauncherResultWithLineInfo = LauncherResult<T>;
+
+using WindowsErrorType = LauncherError;
+
+#else
+
+template <typename T>
+using LauncherResult = WindowsErrorResult<T>;
+
+template <typename T>
+using LauncherResultWithLineInfo = Result<T, LauncherError>;
+
+using WindowsErrorType = WindowsError;
+
+#endif  // defined(MOZ_USE_LAUNCHER_ERROR)
+
+using LauncherVoidResult = LauncherResult<Ok>;
+
+using LauncherVoidResultWithLineInfo = LauncherResultWithLineInfo<Ok>;
+
+#if defined(MOZ_USE_LAUNCHER_ERROR)
+
+#  define LAUNCHER_ERROR_GENERIC()           \
+    ::mozilla::Err(::mozilla::LauncherError( \
+        __FILE__, __LINE__, ::mozilla::WindowsError::CreateGeneric()))
+
+#  if defined(NIGHTLY_BUILD)
+#    define LAUNCHER_ERROR_FROM_DETOUR_ERROR(err) \
+      ::mozilla::Err(::mozilla::LauncherError(__FILE__, __LINE__, err))
+#  else
+#    define LAUNCHER_ERROR_FROM_DETOUR_ERROR(err) LAUNCHER_ERROR_GENERIC()
+#  endif  // defined(NIGHTLY_BUILD)
+
+#  define LAUNCHER_ERROR_FROM_WIN32(err)     \
+    ::mozilla::Err(::mozilla::LauncherError( \
+        __FILE__, __LINE__, ::mozilla::WindowsError::FromWin32Error(err)))
+
+#  define LAUNCHER_ERROR_FROM_LAST()         \
+    ::mozilla::Err(::mozilla::LauncherError( \
+        __FILE__, __LINE__, ::mozilla::WindowsError::FromLastError()))
+
+#  define LAUNCHER_ERROR_FROM_NTSTATUS(ntstatus) \
+    ::mozilla::Err(::mozilla::LauncherError(     \
+        __FILE__, __LINE__, ::mozilla::WindowsError::FromNtStatus(ntstatus)))
+
+#  define LAUNCHER_ERROR_FROM_HRESULT(hresult) \
+    ::mozilla::Err(::mozilla::LauncherError(   \
+        __FILE__, __LINE__, ::mozilla::WindowsError::FromHResult(hresult)))
+
+// This macro wraps the supplied WindowsError with a LauncherError
+#  define LAUNCHER_ERROR_FROM_MOZ_WINDOWS_ERROR(err) \
+    ::mozilla::Err(::mozilla::LauncherError(__FILE__, __LINE__, err))
+
+#else
+
+#  define LAUNCHER_ERROR_GENERIC() \
+    ::mozilla::Err(::mozilla::WindowsError::CreateGeneric())
+
+#  define LAUNCHER_ERROR_FROM_DETOUR_ERROR(err) LAUNCHER_ERROR_GENERIC()
+
+#  define LAUNCHER_ERROR_FROM_WIN32(err) \
+    ::mozilla::Err(::mozilla::WindowsError::FromWin32Error(err))
+
+#  define LAUNCHER_ERROR_FROM_LAST() \
+    ::mozilla::Err(::mozilla::WindowsError::FromLastError())
+
+#  define LAUNCHER_ERROR_FROM_NTSTATUS(ntstatus) \
+    ::mozilla::Err(::mozilla::WindowsError::FromNtStatus(ntstatus))
+
+#  define LAUNCHER_ERROR_FROM_HRESULT(hresult) \
+    ::mozilla::Err(::mozilla::WindowsError::FromHResult(hresult))
+
+#  define LAUNCHER_ERROR_FROM_MOZ_WINDOWS_ERROR(err) ::mozilla::Err(err)
+
+#endif  // defined(MOZ_USE_LAUNCHER_ERROR)
+
+// How long to wait for a created process to become available for input,
+// to prevent that process's windows being forced to the background.
+// This is used across update, restart, and the launcher.
+const DWORD kWaitForInputIdleTimeoutMS = 10 * 1000;
+
+/**
+ * Wait for a child GUI process to become "idle." Idle means that the process
+ * has created its message queue and has begun waiting for user input.
+ *
+ * Note that this must only be used when the child process is going to display
+ * GUI! Otherwise you're going to be waiting for a very long time ;-)
+ *
+ * @return true if we successfully waited for input idle;
+ *         false if we timed out or failed to wait.
+ */
+inline bool WaitForInputIdle(HANDLE aProcess,
+                             DWORD aTimeoutMs = kWaitForInputIdleTimeoutMS) {
+  const DWORD kSleepTimeMs = 10;
+  const DWORD waitStart = aTimeoutMs == INFINITE ? 0 : ::GetTickCount();
+  DWORD elapsed = 0;
+
+  while (true) {
+    if (aTimeoutMs != INFINITE) {
+      elapsed = ::GetTickCount() - waitStart;
+    }
+
+    if (elapsed >= aTimeoutMs) {
+      return false;
+    }
+
+    // ::WaitForInputIdle() doesn't always set the last-error code on failure
+    ::SetLastError(ERROR_SUCCESS);
+
+    DWORD waitResult = ::WaitForInputIdle(aProcess, aTimeoutMs - elapsed);
+    if (!waitResult) {
+      return true;
+    }
+
+    if (waitResult == WAIT_FAILED &&
+        ::GetLastError() == ERROR_NOT_GUI_PROCESS) {
+      ::Sleep(kSleepTimeMs);
+      continue;
+    }
+
+    return false;
+  }
+}
+
+enum class PathType {
+  eNtPath,
+  eDosPath,
+};
+
+class FileUniqueId final {
+ public:
+  explicit FileUniqueId(const wchar_t* aPath, PathType aPathType)
+      : mId(FILE_ID_INFO()) {
+    if (!aPath) {
+      mId = LAUNCHER_ERROR_FROM_HRESULT(E_INVALIDARG);
+      return;
+    }
+
+    nsAutoHandle file;
+
+    switch (aPathType) {
+      default:
+        mId = LAUNCHER_ERROR_FROM_HRESULT(E_INVALIDARG);
+        MOZ_ASSERT_UNREACHABLE("Unhandled PathType");
+        return;
+
+      case PathType::eNtPath: {
+        UNICODE_STRING unicodeString;
+        ::RtlInitUnicodeString(&unicodeString, aPath);
+        OBJECT_ATTRIBUTES objectAttributes;
+        InitializeObjectAttributes(&objectAttributes, &unicodeString,
+                                   OBJ_CASE_INSENSITIVE, nullptr, nullptr);
+        IO_STATUS_BLOCK ioStatus = {};
+        HANDLE ntHandle;
+        NTSTATUS status = ::NtOpenFile(
+            &ntHandle, SYNCHRONIZE | FILE_READ_ATTRIBUTES, &objectAttributes,
+            &ioStatus, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+            FILE_SYNCHRONOUS_IO_NONALERT | FILE_OPEN_FOR_BACKUP_INTENT);
+        // We don't need to check |ntHandle| for INVALID_HANDLE_VALUE here,
+        // as that value is set by the Win32 layer.
+        if (!NT_SUCCESS(status)) {
+          mId = LAUNCHER_ERROR_FROM_NTSTATUS(status);
+          return;
+        }
+
+        file.own(ntHandle);
+        break;
+      }
+
+      case PathType::eDosPath: {
+        file.own(::CreateFileW(
+            aPath, 0, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+            nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, nullptr));
+        if (file == INVALID_HANDLE_VALUE) {
+          mId = LAUNCHER_ERROR_FROM_LAST();
+          return;
+        }
+
+        break;
+      }
+    }
+
+    GetId(file);
+  }
+
+  explicit FileUniqueId(const nsAutoHandle& aFile) : mId(FILE_ID_INFO()) {
+    GetId(aFile);
+  }
+
+  ~FileUniqueId() = default;
+
+  bool IsError() const { return mId.isErr(); }
+
+  const WindowsErrorType& GetError() const { return mId.inspectErr(); }
+
+  FileUniqueId(FileUniqueId&& aOther) = default;
+  FileUniqueId& operator=(FileUniqueId&& aOther) = delete;
+
+  bool operator==(const FileUniqueId& aOther) const {
+    return mId.isOk() && aOther.mId.isOk() &&
+           !memcmp(&mId.inspect(), &aOther.mId.inspect(), sizeof(FILE_ID_INFO));
+  }
+
+  bool operator!=(const FileUniqueId& aOther) const {
+    return !((*this) == aOther);
+  }
+
+ private:
+  void GetId(const nsAutoHandle& aFile) {
+    FILE_ID_INFO fileIdInfo = {};
+    if (::GetFileInformationByHandleEx(aFile.get(), FileIdInfo, &fileIdInfo,
+                                       sizeof(fileIdInfo))) {
+      mId = fileIdInfo;
+      return;
+    }
+    // Only NTFS and ReFS support FileIdInfo. So we have to fallback if
+    // GetFileInformationByHandleEx failed.
+
+    BY_HANDLE_FILE_INFORMATION info = {};
+    if (!::GetFileInformationByHandle(aFile.get(), &info)) {
+      mId = LAUNCHER_ERROR_FROM_LAST();
+      return;
+    }
+
+    fileIdInfo.VolumeSerialNumber = info.dwVolumeSerialNumber;
+    memcpy(&fileIdInfo.FileId.Identifier[0], &info.nFileIndexLow,
+           sizeof(DWORD));
+    memcpy(&fileIdInfo.FileId.Identifier[sizeof(DWORD)], &info.nFileIndexHigh,
+           sizeof(DWORD));
+    mId = fileIdInfo;
+  }
+
+ private:
+  LauncherResult<FILE_ID_INFO> mId;
+};
+
+class MOZ_RAII AutoVirtualProtect final {
+ public:
+  AutoVirtualProtect(void* aAddress, size_t aLength, DWORD aProtFlags,
+                     HANDLE aTargetProcess = ::GetCurrentProcess())
+      : mAddress(aAddress),
+        mLength(aLength),
+        mTargetProcess(aTargetProcess),
+        mPrevProt(0),
+        mError(WindowsError::CreateSuccess()) {
+    if (!::VirtualProtectEx(aTargetProcess, aAddress, aLength, aProtFlags,
+                            &mPrevProt)) {
+      mError = WindowsError::FromLastError();
+    }
+  }
+
+  ~AutoVirtualProtect() {
+    if (mError.IsFailure()) {
+      return;
+    }
+
+    ::VirtualProtectEx(mTargetProcess, mAddress, mLength, mPrevProt,
+                       &mPrevProt);
+  }
+
+  explicit operator bool() const { return mError.IsSuccess(); }
+
+  WindowsError GetError() const { return mError; }
+
+  DWORD PrevProt() const { return mPrevProt; }
+
+  AutoVirtualProtect(const AutoVirtualProtect&) = delete;
+  AutoVirtualProtect(AutoVirtualProtect&&) = delete;
+  AutoVirtualProtect& operator=(const AutoVirtualProtect&) = delete;
+  AutoVirtualProtect& operator=(AutoVirtualProtect&&) = delete;
+
+ private:
+  void* mAddress;
+  size_t mLength;
+  HANDLE mTargetProcess;
+  DWORD mPrevProt;
+  WindowsError mError;
+};
+
+inline UniquePtr<wchar_t[]> GetFullModulePath(HMODULE aModule) {
+  DWORD bufLen = MAX_PATH;
+  mozilla::UniquePtr<wchar_t[]> buf;
+  DWORD retLen;
+
+  while (true) {
+    buf = mozilla::MakeUnique<wchar_t[]>(bufLen);
+    retLen = ::GetModuleFileNameW(aModule, buf.get(), bufLen);
+    if (!retLen) {
+      return nullptr;
+    }
+
+    if (retLen == bufLen && ::GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
+      bufLen *= 2;
+      continue;
+    }
+
+    break;
+  }
+
+  // Upon success, retLen *excludes* the null character
+  ++retLen;
+
+  // Since we're likely to have a bunch of unused space in buf, let's
+  // reallocate a string to the actual size of the file name.
+  auto result = mozilla::MakeUnique<wchar_t[]>(retLen);
+  if (wcscpy_s(result.get(), retLen, buf.get())) {
+    return nullptr;
+  }
+
+  return result;
+}
+
+inline UniquePtr<wchar_t[]> GetFullBinaryPath() {
+  return GetFullModulePath(nullptr);
+}
+
+// Generates the install directory without a trailing path separator.
+inline bool GetInstallDirectory(UniquePtr<wchar_t[]>& installPath) {
+  installPath = GetFullBinaryPath();
+  // It's not safe to use PathRemoveFileSpecW with strings longer than MAX_PATH
+  // (including null terminator).
+  if (wcslen(installPath.get()) >= MAX_PATH) {
+    return false;
+  }
+  ::PathRemoveFileSpecW(installPath.get());
+  return true;
+}
+
+class ModuleVersion final {
+ public:
+  constexpr ModuleVersion() : mVersion(0ULL) {}
+
+  explicit ModuleVersion(const VS_FIXEDFILEINFO& aFixedInfo)
+      : mVersion((static_cast<uint64_t>(aFixedInfo.dwFileVersionMS) << 32) |
+                 static_cast<uint64_t>(aFixedInfo.dwFileVersionLS)) {}
+
+  explicit ModuleVersion(const uint64_t aVersion) : mVersion(aVersion) {}
+
+  ModuleVersion(const ModuleVersion& aOther) : mVersion(aOther.mVersion) {}
+
+  uint64_t AsInteger() const { return mVersion; }
+
+  operator uint64_t() const { return AsInteger(); }
+
+  std::tuple<uint16_t, uint16_t, uint16_t, uint16_t> AsTuple() const {
+    uint16_t major = static_cast<uint16_t>((mVersion >> 48) & 0xFFFFU);
+    uint16_t minor = static_cast<uint16_t>((mVersion >> 32) & 0xFFFFU);
+    uint16_t patch = static_cast<uint16_t>((mVersion >> 16) & 0xFFFFU);
+    uint16_t build = static_cast<uint16_t>(mVersion & 0xFFFFU);
+
+    return {major, minor, patch, build};
+  }
+
+  explicit operator bool() const { return !!mVersion; }
+
+  bool operator<(const ModuleVersion& aOther) const {
+    return mVersion < aOther.mVersion;
+  }
+
+  bool operator<(const uint64_t& aOther) const { return mVersion < aOther; }
+
+  ModuleVersion& operator=(const uint64_t aIntVersion) {
+    mVersion = aIntVersion;
+    return *this;
+  }
+
+ private:
+  uint64_t mVersion;
+};
+
+inline LauncherResult<ModuleVersion> GetModuleVersion(
+    const wchar_t* aModuleFullPath) {
+  DWORD verInfoLen = ::GetFileVersionInfoSizeW(aModuleFullPath, nullptr);
+  if (!verInfoLen) {
+    return LAUNCHER_ERROR_FROM_LAST();
+  }
+
+  auto verInfoBuf = MakeUnique<BYTE[]>(verInfoLen);
+  if (!::GetFileVersionInfoW(aModuleFullPath, 0, verInfoLen,
+                             verInfoBuf.get())) {
+    return LAUNCHER_ERROR_FROM_LAST();
+  }
+
+  UINT fixedInfoLen;
+  VS_FIXEDFILEINFO* fixedInfo = nullptr;
+  if (!::VerQueryValueW(verInfoBuf.get(), L"\\",
+                        reinterpret_cast<LPVOID*>(&fixedInfo), &fixedInfoLen)) {
+    // VerQueryValue may fail if the resource does not exist. This is not an
+    // error; we'll return 0 in this case.
+    return ModuleVersion(0ULL);
+  }
+
+  return ModuleVersion(*fixedInfo);
+}
+
+inline LauncherResult<ModuleVersion> GetModuleVersion(HMODULE aModule) {
+  UniquePtr<wchar_t[]> fullPath(GetFullModulePath(aModule));
+  if (!fullPath) {
+    return LAUNCHER_ERROR_GENERIC();
+  }
+
+  return GetModuleVersion(fullPath.get());
+}
+
+#if defined(MOZILLA_INTERNAL_API)
+inline LauncherResult<ModuleVersion> GetModuleVersion(nsIFile* aFile) {
+  if (!aFile) {
+    return LAUNCHER_ERROR_FROM_HRESULT(E_INVALIDARG);
+  }
+
+  nsAutoString fullPath;
+  nsresult rv = aFile->GetPath(fullPath);
+  if (NS_FAILED(rv)) {
+    return LAUNCHER_ERROR_GENERIC();
+  }
+
+  return GetModuleVersion(fullPath.get());
+}
+#endif  // defined(MOZILLA_INTERNAL_API)
+
+struct CoTaskMemFreeDeleter {
+  void operator()(void* aPtr) { ::CoTaskMemFree(aPtr); }
+};
+
+inline LauncherResult<TOKEN_ELEVATION_TYPE> GetElevationType(
+    const nsAutoHandle& aToken) {
+  DWORD retLen;
+  TOKEN_ELEVATION_TYPE elevationType;
+  if (!::GetTokenInformation(aToken.get(), TokenElevationType, &elevationType,
+                             sizeof(elevationType), &retLen)) {
+    return LAUNCHER_ERROR_FROM_LAST();
+  }
+
+  return elevationType;
+}
+
+inline bool HasPackageIdentity() {
+  HMODULE kernel32Dll = ::GetModuleHandleW(L"kernel32");
+  if (!kernel32Dll) {
+    return false;
+  }
+
+  typedef LONG(WINAPI * GetCurrentPackageIdProc)(UINT32*, BYTE*);
+  GetCurrentPackageIdProc pGetCurrentPackageId =
+      (GetCurrentPackageIdProc)::GetProcAddress(kernel32Dll,
+                                                "GetCurrentPackageId");
+
+  // If there was any package identity to retrieve, we get
+  // ERROR_INSUFFICIENT_BUFFER. If there had been no package identity it
+  // would instead return APPMODEL_ERROR_NO_PACKAGE.
+  UINT32 packageNameSize = 0;
+  return pGetCurrentPackageId &&
+         (pGetCurrentPackageId(&packageNameSize, nullptr) ==
+          ERROR_INSUFFICIENT_BUFFER);
+}
+
+inline UniquePtr<wchar_t[]> GetPackageFamilyName() {
+  HMODULE kernel32Dll = ::GetModuleHandleW(L"kernel32");
+  if (!kernel32Dll) {
+    return nullptr;
+  }
+
+  typedef LONG(WINAPI * GetCurrentPackageFamilyNameProc)(UINT32*, PWSTR);
+  GetCurrentPackageFamilyNameProc pGetCurrentPackageFamilyName =
+      (GetCurrentPackageFamilyNameProc)::GetProcAddress(
+          kernel32Dll, "GetCurrentPackageFamilyName");
+  if (!pGetCurrentPackageFamilyName) {
+    return nullptr;
+  }
+
+  UINT32 packageNameSize = 0;
+  if (pGetCurrentPackageFamilyName(&packageNameSize, nullptr) !=
+      ERROR_INSUFFICIENT_BUFFER) {
+    return nullptr;
+  }
+
+  UniquePtr<wchar_t[]> packageIdentity = MakeUnique<wchar_t[]>(packageNameSize);
+  if (pGetCurrentPackageFamilyName(&packageNameSize, packageIdentity.get()) !=
+      ERROR_SUCCESS) {
+    return nullptr;
+  }
+
+  return packageIdentity;
+}
+
+// This implementation is equivalent to PathGetDriveNumber[AW].
+// We define our own version because using PathGetDriveNumber
+// delay-loads shlwapi.dll, which may fail when the process is
+// sandboxed.
+template <typename T>
+int MozPathGetDriveNumber(const T* aPath) {
+  const auto ToDriveNumber = [](const T* aPath) -> int {
+    if (*aPath == '\0' || *(aPath + 1) != ':') {
+      return -1;
+    }
+
+    T c = *aPath;
+    return (c >= 'A' && c <= 'Z')   ? c - 'A'
+           : (c >= 'a' && c <= 'z') ? c - 'a'
+                                    : -1;
+  };
+
+  if (!aPath) {
+    return -1;
+  }
+
+  if (*aPath == '\\' && *(aPath + 1) == '\\' && *(aPath + 2) == '?' &&
+      *(aPath + 3) == '\\') {
+    return ToDriveNumber(aPath + 4);
+  }
+
+  return ToDriveNumber(aPath);
+}
+
+}  // namespace mozilla
+
+#endif  // mozilla_WinHeaderOnlyUtils_h
diff --git a/widget/windows/WinIMEHandler.cpp b/widget/windows/WinIMEHandler.cpp
new file mode 100644
index 0000000000..961c61fae0
--- /dev/null
+++ b/widget/windows/WinIMEHandler.cpp
@@ -0,0 +1,1081 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WinIMEHandler.h"
+
+#include "IMMHandler.h"
+#include "KeyboardLayout.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_intl.h"
+#include "mozilla/StaticPrefs_ui.h"
+#include "mozilla/TextEvents.h"
+#include "mozilla/Unused.h"
+#include "mozilla/WindowsVersion.h"
+#include "nsWindowDefs.h"
+#include "WinTextEventDispatcherListener.h"
+
+#include "TSFTextStore.h"
+
+#include "OSKInputPaneManager.h"
+#include "OSKTabTipManager.h"
+#include "OSKVRManager.h"
+#include "nsLookAndFeel.h"
+#include "nsWindow.h"
+#include "WinUtils.h"
+#include "nsIWindowsRegKey.h"
+#include "WindowsUIUtils.h"
+
+#ifdef ACCESSIBILITY
+#  include "nsAccessibilityService.h"
+#endif  // #ifdef ACCESSIBILITY
+
+#include "shellapi.h"
+#include "shlobj.h"
+#include "powrprof.h"
+#include "setupapi.h"
+#include "cfgmgr32.h"
+
+#include "FxRWindowManager.h"
+#include "moz_external_vr.h"
+
+const char* kOskEnabled = "ui.osk.enabled";
+const char* kOskDetectPhysicalKeyboard = "ui.osk.detect_physical_keyboard";
+const char* kOskDebugReason = "ui.osk.debug.keyboardDisplayReason";
+
+namespace mozilla {
+namespace widget {
+
+/******************************************************************************
+ * IMEHandler
+ ******************************************************************************/
+
+nsWindow* IMEHandler::sFocusedWindow = nullptr;
+InputContextAction::Cause IMEHandler::sLastContextActionCause =
+    InputContextAction::CAUSE_UNKNOWN;
+bool IMEHandler::sMaybeEditable = false;
+bool IMEHandler::sForceDisableCurrentIMM_IME = false;
+bool IMEHandler::sNativeCaretIsCreated = false;
+bool IMEHandler::sHasNativeCaretBeenRequested = false;
+
+bool IMEHandler::sIsInTSFMode = false;
+bool IMEHandler::sIsIMMEnabled = true;
+decltype(SetInputScopes)* IMEHandler::sSetInputScopes = nullptr;
+
+static POWER_PLATFORM_ROLE sPowerPlatformRole = PlatformRoleUnspecified;
+static bool sDeterminedPowerPlatformRole = false;
+
+// static
+void IMEHandler::Initialize() {
+  TSFTextStore::Initialize();
+  sIsInTSFMode = TSFTextStore::IsInTSFMode();
+  sIsIMMEnabled =
+      !sIsInTSFMode || StaticPrefs::intl_tsf_support_imm_AtStartup();
+  if (!sIsInTSFMode) {
+    // When full TSFTextStore is not available, try to use SetInputScopes API
+    // to enable at least InputScope. Use GET_MODULE_HANDLE_EX_FLAG_PIN to
+    // ensure that msctf.dll will not be unloaded.
+    HMODULE module = nullptr;
+    if (GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_PIN, L"msctf.dll",
+                           &module)) {
+      sSetInputScopes = reinterpret_cast<decltype(SetInputScopes)*>(
+          GetProcAddress(module, "SetInputScopes"));
+    }
+  }
+
+  IMMHandler::Initialize();
+
+  sForceDisableCurrentIMM_IME = IMMHandler::IsActiveIMEInBlockList();
+}
+
+// static
+void IMEHandler::Terminate() {
+  if (sIsInTSFMode) {
+    TSFTextStore::Terminate();
+    sIsInTSFMode = false;
+  }
+
+  IMMHandler::Terminate();
+  WinTextEventDispatcherListener::Shutdown();
+}
+
+// static
+void* IMEHandler::GetNativeData(nsWindow* aWindow, uint32_t aDataType) {
+  if (aDataType == NS_RAW_NATIVE_IME_CONTEXT) {
+    if (IsTSFAvailable()) {
+      return TSFTextStore::GetThreadManager();
+    }
+    IMEContext context(aWindow);
+    if (context.IsValid()) {
+      return context.get();
+    }
+    // If IMC isn't associated with the window, IME is disabled on the window
+    // now.  In such case, we should return default IMC instead.
+    const IMEContext& defaultIMC = aWindow->DefaultIMC();
+    if (defaultIMC.IsValid()) {
+      return defaultIMC.get();
+    }
+    // If there is no default IMC, we should return the pointer to the window
+    // since if we return nullptr, IMEStateManager cannot manage composition
+    // with TextComposition instance.  This is possible if no IME is installed,
+    // but composition may occur with dead key sequence.
+    return aWindow;
+  }
+
+  void* result = TSFTextStore::GetNativeData(aDataType);
+  if (!result || !(*(static_cast<void**>(result)))) {
+    return nullptr;
+  }
+  // XXX During the TSF module test, sIsInTSFMode must be true.  After that,
+  //     the value should be restored but currently, there is no way for that.
+  //     When the TSF test is enabled again, we need to fix this.  Perhaps,
+  //     sending a message can fix this.
+  sIsInTSFMode = true;
+  return result;
+}
+
+// static
+bool IMEHandler::ProcessRawKeyMessage(const MSG& aMsg) {
+  if (StaticPrefs::ui_key_layout_load_when_first_needed()) {
+    // Getting instance creates the singleton instance and that will
+    // automatically load active keyboard layout data.  We should do that
+    // before TSF or TranslateMessage handles a key message.
+    Unused << KeyboardLayout::GetInstance();
+  }
+  if (IsTSFAvailable()) {
+    return TSFTextStore::ProcessRawKeyMessage(aMsg);
+  }
+  return false;  // noting to do in IMM mode.
+}
+
+// static
+bool IMEHandler::ProcessMessage(nsWindow* aWindow, UINT aMessage,
+                                WPARAM& aWParam, LPARAM& aLParam,
+                                MSGResult& aResult) {
+  // If we're putting native caret over our caret, Windows dispatches
+  // EVENT_OBJECT_LOCATIONCHANGE event on other applications which hook
+  // the event with ::SetWinEventHook() and handles WM_GETOBJECT for
+  // OBJID_CARET (this is request of caret from such applications) instead
+  // of us.  If a11y module is active, it observes every our caret change
+  // and put native caret over it automatically.  However, if other
+  // applications require only caret information, activating a11y module is
+  // overwork and such applications may requires carets only in editors.
+  // Therefore, if it'd be possible, IMEHandler should put native caret over
+  // our caret, but there is a problem.  Some versions of ATOK (Japanese TIP)
+  // refer native caret and if there is, the behavior is worse than the
+  // behavior without native caret.  Therefore, we shouldn't put native caret
+  // as far as possible.
+  if (!sHasNativeCaretBeenRequested && aMessage == WM_GETOBJECT &&
+      static_cast<LONG>(aLParam) == OBJID_CARET) {
+    // So, when we receive first WM_GETOBJECT for OBJID_CARET, let's start to
+    // create native caret for such applications.
+    sHasNativeCaretBeenRequested = true;
+    // If an editable element has focus, we can put native caret now.
+    // XXX Should we avoid doing this if there is composition?
+    MaybeCreateNativeCaret(aWindow);
+  }
+
+  if (IsTSFAvailable()) {
+    TSFTextStore::ProcessMessage(aWindow, aMessage, aWParam, aLParam, aResult);
+    if (aResult.mConsumed) {
+      return true;
+    }
+    // If we don't support IMM in TSF mode, we don't use IMMHandler.
+    if (!sIsIMMEnabled) {
+      return false;
+    }
+    // IME isn't implemented with IMM, IMMHandler shouldn't handle any
+    // messages.
+    if (!IsIMMActive()) {
+      return false;
+    }
+  }
+
+  bool keepGoing =
+      IMMHandler::ProcessMessage(aWindow, aMessage, aWParam, aLParam, aResult);
+
+  // If user changes active IME to an IME which is listed in our block list,
+  // we should disassociate IMC from the window for preventing the IME to work
+  // and crash.
+  if (aMessage == WM_INPUTLANGCHANGE) {
+    bool disableIME = IMMHandler::IsActiveIMEInBlockList();
+    if (disableIME != sForceDisableCurrentIMM_IME) {
+      bool enable =
+          !disableIME && WinUtils::IsIMEEnabled(aWindow->InputContextRef());
+      AssociateIMEContext(aWindow, enable);
+      sForceDisableCurrentIMM_IME = disableIME;
+    }
+  }
+
+  return keepGoing;
+}
+
+// static
+bool IMEHandler::IsA11yHandlingNativeCaret() {
+#ifndef ACCESSIBILITY
+  return false;
+#else   // #ifndef ACCESSIBILITY
+  // Let's assume that when there is the service, it handles native caret.
+  return GetAccService() != nullptr;
+#endif  // #ifndef ACCESSIBILITY #else
+}
+
+// static
+bool IMEHandler::IsIMMActive() { return TSFTextStore::IsIMM_IMEActive(); }
+
+// static
+bool IMEHandler::IsComposing() {
+  if (IsTSFAvailable()) {
+    return TSFTextStore::IsComposing() || IMMHandler::IsComposing();
+  }
+
+  return IMMHandler::IsComposing();
+}
+
+// static
+bool IMEHandler::IsComposingOn(nsWindow* aWindow) {
+  if (IsTSFAvailable()) {
+    return TSFTextStore::IsComposingOn(aWindow) ||
+           IMMHandler::IsComposingOn(aWindow);
+  }
+
+  return IMMHandler::IsComposingOn(aWindow);
+}
+
+// static
+nsresult IMEHandler::NotifyIME(nsWindow* aWindow,
+                               const IMENotification& aIMENotification) {
+  if (IsTSFAvailable()) {
+    switch (aIMENotification.mMessage) {
+      case NOTIFY_IME_OF_SELECTION_CHANGE: {
+        nsresult rv = TSFTextStore::OnSelectionChange(aIMENotification);
+        // If IMM IME is active, we need to notify IMMHandler of updating
+        // composition change.  It will adjust candidate window position or
+        // composition window position.
+        bool isIMMActive = IsIMMActive();
+        if (isIMMActive) {
+          IMMHandler::OnUpdateComposition(aWindow);
+        }
+        IMMHandler::OnSelectionChange(aWindow, aIMENotification, isIMMActive);
+        return rv;
+      }
+      case NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED:
+        // If IMM IME is active, we need to notify IMMHandler of updating
+        // composition change.  It will adjust candidate window position or
+        // composition window position.
+        if (IsIMMActive()) {
+          IMMHandler::OnUpdateComposition(aWindow);
+        } else {
+          TSFTextStore::OnUpdateComposition();
+        }
+        return NS_OK;
+      case NOTIFY_IME_OF_TEXT_CHANGE:
+        return TSFTextStore::OnTextChange(aIMENotification);
+      case NOTIFY_IME_OF_FOCUS: {
+        sFocusedWindow = aWindow;
+        IMMHandler::OnFocusChange(true, aWindow);
+        nsresult rv = TSFTextStore::OnFocusChange(true, aWindow,
+                                                  aWindow->GetInputContext());
+        MaybeCreateNativeCaret(aWindow);
+        IMEHandler::MaybeShowOnScreenKeyboard(aWindow,
+                                              aWindow->GetInputContext());
+        return rv;
+      }
+      case NOTIFY_IME_OF_BLUR:
+        sFocusedWindow = nullptr;
+        IMEHandler::MaybeDismissOnScreenKeyboard(aWindow);
+        IMMHandler::OnFocusChange(false, aWindow);
+        return TSFTextStore::OnFocusChange(false, aWindow,
+                                           aWindow->GetInputContext());
+      case NOTIFY_IME_OF_MOUSE_BUTTON_EVENT:
+        // If IMM IME is active, we should send a mouse button event via IMM.
+        if (IsIMMActive()) {
+          return IMMHandler::OnMouseButtonEvent(aWindow, aIMENotification);
+        }
+        return TSFTextStore::OnMouseButtonEvent(aIMENotification);
+      case REQUEST_TO_COMMIT_COMPOSITION:
+        if (TSFTextStore::IsComposingOn(aWindow)) {
+          TSFTextStore::CommitComposition(false);
+        } else if (IsIMMActive()) {
+          IMMHandler::CommitComposition(aWindow);
+        }
+        return NS_OK;
+      case REQUEST_TO_CANCEL_COMPOSITION:
+        if (TSFTextStore::IsComposingOn(aWindow)) {
+          TSFTextStore::CommitComposition(true);
+        } else if (IsIMMActive()) {
+          IMMHandler::CancelComposition(aWindow);
+        }
+        return NS_OK;
+      case NOTIFY_IME_OF_POSITION_CHANGE:
+        return TSFTextStore::OnLayoutChange();
+      default:
+        return NS_ERROR_NOT_IMPLEMENTED;
+    }
+  }
+
+  switch (aIMENotification.mMessage) {
+    case REQUEST_TO_COMMIT_COMPOSITION:
+      IMMHandler::CommitComposition(aWindow);
+      return NS_OK;
+    case REQUEST_TO_CANCEL_COMPOSITION:
+      IMMHandler::CancelComposition(aWindow);
+      return NS_OK;
+    case NOTIFY_IME_OF_POSITION_CHANGE:
+    case NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED:
+      IMMHandler::OnUpdateComposition(aWindow);
+      return NS_OK;
+    case NOTIFY_IME_OF_SELECTION_CHANGE:
+      IMMHandler::OnSelectionChange(aWindow, aIMENotification, true);
+      // IMMHandler::OnSelectionChange() cannot work without its singleton
+      // instance.  Therefore, IMEHandler needs to create native caret instead
+      // if it's necessary.
+      MaybeCreateNativeCaret(aWindow);
+      return NS_OK;
+    case NOTIFY_IME_OF_MOUSE_BUTTON_EVENT:
+      return IMMHandler::OnMouseButtonEvent(aWindow, aIMENotification);
+    case NOTIFY_IME_OF_FOCUS:
+      sFocusedWindow = aWindow;
+      IMMHandler::OnFocusChange(true, aWindow);
+      IMEHandler::MaybeShowOnScreenKeyboard(aWindow,
+                                            aWindow->GetInputContext());
+      MaybeCreateNativeCaret(aWindow);
+      return NS_OK;
+    case NOTIFY_IME_OF_BLUR:
+      sFocusedWindow = nullptr;
+      IMEHandler::MaybeDismissOnScreenKeyboard(aWindow);
+      IMMHandler::OnFocusChange(false, aWindow);
+      // If a plugin gets focus while TSF has focus, we need to notify TSF of
+      // the blur.
+      if (TSFTextStore::ThinksHavingFocus()) {
+        return TSFTextStore::OnFocusChange(false, aWindow,
+                                           aWindow->GetInputContext());
+      }
+      return NS_OK;
+    default:
+      return NS_ERROR_NOT_IMPLEMENTED;
+  }
+}
+
+// static
+IMENotificationRequests IMEHandler::GetIMENotificationRequests() {
+  if (IsTSFAvailable()) {
+    if (!sIsIMMEnabled) {
+      return TSFTextStore::GetIMENotificationRequests();
+    }
+    // Even if TSF is available, the active IME may be an IMM-IME.
+    // Unfortunately, changing the result of GetIMENotificationRequests() while
+    // an editor has focus isn't supported by IMEContentObserver nor
+    // ContentCacheInParent.  Therefore, we need to request whole notifications
+    // which are necessary either IMMHandler or TSFTextStore.
+    return IMMHandler::GetIMENotificationRequests() |
+           TSFTextStore::GetIMENotificationRequests();
+  }
+
+  return IMMHandler::GetIMENotificationRequests();
+}
+
+// static
+TextEventDispatcherListener*
+IMEHandler::GetNativeTextEventDispatcherListener() {
+  return WinTextEventDispatcherListener::GetInstance();
+}
+
+// static
+bool IMEHandler::GetOpenState(nsWindow* aWindow) {
+  if (IsTSFAvailable() && !IsIMMActive()) {
+    return TSFTextStore::GetIMEOpenState();
+  }
+
+  IMEContext context(aWindow);
+  return context.GetOpenState();
+}
+
+// static
+void IMEHandler::OnDestroyWindow(nsWindow* aWindow) {
+  // When focus is in remote process, but the window is being destroyed, we
+  // need to clean up TSFTextStore here since NOTIFY_IME_OF_BLUR won't reach
+  // here because BrowserParent already lost the reference to the nsWindow when
+  // it receives from the remote process.
+  if (sFocusedWindow == aWindow) {
+    MOZ_ASSERT(aWindow->GetInputContext().IsOriginContentProcess(),
+               "input context of focused widget should've been set by a remote "
+               "process "
+               "if IME focus isn't cleared before destroying the widget");
+    NotifyIME(aWindow, IMENotification(NOTIFY_IME_OF_BLUR));
+  }
+
+  // We need to do nothing here for TSF. Just restore the default context
+  // if it's been disassociated.
+  if (!sIsInTSFMode) {
+    // MSDN says we need to set IS_DEFAULT to avoid memory leak when we use
+    // SetInputScopes API. Use an empty string to do this.
+    SetInputScopeForIMM32(aWindow, u""_ns, u""_ns, false);
+  }
+  AssociateIMEContext(aWindow, true);
+}
+
+// static
+bool IMEHandler::NeedsToAssociateIMC() { return !sForceDisableCurrentIMM_IME; }
+
+// static
+void IMEHandler::SetInputContext(nsWindow* aWindow, InputContext& aInputContext,
+                                 const InputContextAction& aAction) {
+  sLastContextActionCause = aAction.mCause;
+  // FYI: If there is no composition, this call will do nothing.
+  NotifyIME(aWindow, IMENotification(REQUEST_TO_COMMIT_COMPOSITION));
+
+  if (aInputContext.mHTMLInputMode.EqualsLiteral("none")) {
+    IMEHandler::MaybeDismissOnScreenKeyboard(aWindow, Sync::Yes);
+  } else if (aAction.UserMightRequestOpenVKB()) {
+    IMEHandler::MaybeShowOnScreenKeyboard(aWindow, aInputContext);
+  }
+
+  bool enable = WinUtils::IsIMEEnabled(aInputContext);
+  bool adjustOpenState = (enable && aInputContext.mIMEState.mOpen !=
+                                        IMEState::DONT_CHANGE_OPEN_STATE);
+  bool open =
+      (adjustOpenState && aInputContext.mIMEState.mOpen == IMEState::OPEN);
+
+  // Note that even while a plugin has focus, we need to notify TSF of that.
+  if (sIsInTSFMode) {
+    TSFTextStore::SetInputContext(aWindow, aInputContext, aAction);
+    if (IsTSFAvailable()) {
+      if (sIsIMMEnabled) {
+        // Associate IMC with aWindow only when it's necessary.
+        AssociateIMEContext(aWindow, enable && NeedsToAssociateIMC());
+      }
+      if (adjustOpenState) {
+        TSFTextStore::SetIMEOpenState(open);
+      }
+      return;
+    }
+  } else {
+    // Set at least InputScope even when TextStore is not available.
+    SetInputScopeForIMM32(aWindow, aInputContext.mHTMLInputType,
+                          aInputContext.mHTMLInputMode,
+                          aInputContext.mInPrivateBrowsing);
+  }
+
+  AssociateIMEContext(aWindow, enable);
+
+  IMEContext context(aWindow);
+  if (adjustOpenState) {
+    context.SetOpenState(open);
+  }
+}
+
+// static
+void IMEHandler::AssociateIMEContext(nsWindow* aWindowBase, bool aEnable) {
+  IMEContext context(aWindowBase);
+  if (aEnable) {
+    context.AssociateDefaultContext();
+    return;
+  }
+  // Don't disassociate the context after the window is destroyed.
+  if (aWindowBase->Destroyed()) {
+    return;
+  }
+  context.Disassociate();
+}
+
+// static
+void IMEHandler::InitInputContext(nsWindow* aWindow,
+                                  InputContext& aInputContext) {
+  MOZ_ASSERT(aWindow);
+  MOZ_ASSERT(aWindow->GetWindowHandle(),
+             "IMEHandler::SetInputContext() requires non-nullptr HWND");
+
+  static bool sInitialized = false;
+  if (!sInitialized) {
+    sInitialized = true;
+    // Some TIPs like QQ Input (Simplified Chinese) may need normal window
+    // (i.e., windows except message window) when initializing themselves.
+    // Therefore, we need to initialize TSF/IMM modules after first normal
+    // window is created.  InitInputContext() should be called immediately
+    // after creating each normal window, so, here is a good place to
+    // initialize these modules.
+    Initialize();
+  }
+
+  // For a11y, the default enabled state should be 'enabled'.
+  aInputContext.mIMEState.mEnabled = IMEEnabled::Enabled;
+
+  if (sIsInTSFMode) {
+    TSFTextStore::SetInputContext(
+        aWindow, aInputContext,
+        InputContextAction(InputContextAction::CAUSE_UNKNOWN,
+                           InputContextAction::WIDGET_CREATED));
+    // IME context isn't necessary in pure TSF mode.
+    if (!sIsIMMEnabled) {
+      AssociateIMEContext(aWindow, false);
+    }
+    return;
+  }
+
+#ifdef DEBUG
+  // NOTE: IMC may be null if IMM module isn't installed.
+  IMEContext context(aWindow);
+  MOZ_ASSERT(context.IsValid() || !CurrentKeyboardLayoutHasIME());
+#endif  // #ifdef DEBUG
+}
+
+#ifdef DEBUG
+// static
+bool IMEHandler::CurrentKeyboardLayoutHasIME() {
+  if (sIsInTSFMode) {
+    return TSFTextStore::CurrentKeyboardLayoutHasIME();
+  }
+
+  return IMMHandler::IsIMEAvailable();
+}
+#endif  // #ifdef DEBUG
+
+// static
+void IMEHandler::OnKeyboardLayoutChanged() {
+  // Be aware, this method won't be called until TSFStaticSink starts to
+  // observe active TIP change.  If you need to be notified of this, you
+  // need to create TSFStaticSink::Observe() or something and call it
+  // TSFStaticSink::EnsureInitActiveTIPKeyboard() forcibly.
+
+  if (!sIsIMMEnabled || !IsTSFAvailable()) {
+    return;
+  }
+}
+
+// static
+void IMEHandler::SetInputScopeForIMM32(nsWindow* aWindow,
+                                       const nsAString& aHTMLInputType,
+                                       const nsAString& aHTMLInputMode,
+                                       bool aInPrivateBrowsing) {
+  if (sIsInTSFMode || !sSetInputScopes || aWindow->Destroyed()) {
+    return;
+  }
+  AutoTArray<InputScope, 3> scopes;
+
+  // IME may refer only first input scope, but we will append inputmode's
+  // input scopes since IME may refer it like Chrome.
+  AppendInputScopeFromType(aHTMLInputType, scopes);
+  AppendInputScopeFromInputMode(aHTMLInputMode, scopes);
+
+  if (aInPrivateBrowsing) {
+    scopes.AppendElement(IS_PRIVATE);
+  }
+
+  if (scopes.IsEmpty()) {
+    // At least, 1 item is necessary.
+    scopes.AppendElement(IS_DEFAULT);
+  }
+
+  sSetInputScopes(aWindow->GetWindowHandle(), scopes.Elements(),
+                  scopes.Length(), nullptr, 0, nullptr, nullptr);
+}
+
+// static
+void IMEHandler::AppendInputScopeFromInputMode(const nsAString& aHTMLInputMode,
+                                               nsTArray<InputScope>& aScopes) {
+  if (aHTMLInputMode.EqualsLiteral("mozAwesomebar")) {
+    // Even if Awesomebar has focus, user may not input URL directly.
+    // However, on-screen keyboard for URL should be shown because it has
+    // some useful additional keys like ".com" and they are not hindrances
+    // even when inputting non-URL text, e.g., words to search something in
+    // the web.  On the other hand, a lot of Microsoft's IMEs and Google
+    // Japanese Input make their open state "closed" automatically if we
+    // notify them of URL as the input scope.  However, this is very annoying
+    // for the users when they try to input some words to search the web or
+    // bookmark/history items.  Therefore, if they are active, we need to
+    // notify them of the default input scope for avoiding this issue.
+    // FYI: We cannot check active TIP without TSF.  Therefore, if it's
+    //      not in TSF mode, this will check only if active IMM-IME is Google
+    //      Japanese Input.  Google Japanese Input is a TIP of TSF basically.
+    //      However, if the OS is Win7 or it's installed on Win7 but has not
+    //      been updated yet even after the OS is upgraded to Win8 or later,
+    //      it's installed as IMM-IME.
+    if (TSFTextStore::ShouldSetInputScopeOfURLBarToDefault()) {
+      return;
+    }
+    // Don't append IS_SEARCH here for showing on-screen keyboard for URL.
+    if (!aScopes.Contains(IS_URL)) {
+      aScopes.AppendElement(IS_URL);
+    }
+    return;
+  }
+
+  // https://html.spec.whatwg.org/dev/interaction.html#attr-inputmode
+  if (aHTMLInputMode.EqualsLiteral("url")) {
+    if (!aScopes.Contains(IS_SEARCH)) {
+      aScopes.AppendElement(IS_URL);
+    }
+    return;
+  }
+  if (aHTMLInputMode.EqualsLiteral("email")) {
+    if (!aScopes.Contains(IS_EMAIL_SMTPEMAILADDRESS)) {
+      aScopes.AppendElement(IS_EMAIL_SMTPEMAILADDRESS);
+    }
+    return;
+  }
+  if (aHTMLInputMode.EqualsLiteral("tel")) {
+    if (!aScopes.Contains(IS_TELEPHONE_FULLTELEPHONENUMBER)) {
+      aScopes.AppendElement(IS_TELEPHONE_FULLTELEPHONENUMBER);
+    }
+    if (!aScopes.Contains(IS_TELEPHONE_LOCALNUMBER)) {
+      aScopes.AppendElement(IS_TELEPHONE_LOCALNUMBER);
+    }
+    return;
+  }
+  if (aHTMLInputMode.EqualsLiteral("numeric")) {
+    if (!aScopes.Contains(IS_DIGITS)) {
+      aScopes.AppendElement(IS_DIGITS);
+    }
+    return;
+  }
+  if (aHTMLInputMode.EqualsLiteral("decimal")) {
+    if (!aScopes.Contains(IS_NUMBER)) {
+      aScopes.AppendElement(IS_NUMBER);
+    }
+    return;
+  }
+  if (aHTMLInputMode.EqualsLiteral("search")) {
+    if (NeedsSearchInputScope() && !aScopes.Contains(IS_SEARCH)) {
+      aScopes.AppendElement(IS_SEARCH);
+    }
+    return;
+  }
+}
+
+// static
+void IMEHandler::AppendInputScopeFromType(const nsAString& aHTMLInputType,
+                                          nsTArray<InputScope>& aScopes) {
+  // http://www.whatwg.org/specs/web-apps/current-work/multipage/the-input-element.html
+  if (aHTMLInputType.EqualsLiteral("url")) {
+    aScopes.AppendElement(IS_URL);
+    return;
+  }
+  if (aHTMLInputType.EqualsLiteral("search")) {
+    if (NeedsSearchInputScope()) {
+      aScopes.AppendElement(IS_SEARCH);
+    }
+    return;
+  }
+  if (aHTMLInputType.EqualsLiteral("email")) {
+    aScopes.AppendElement(IS_EMAIL_SMTPEMAILADDRESS);
+    return;
+  }
+  if (aHTMLInputType.EqualsLiteral("password")) {
+    aScopes.AppendElement(IS_PASSWORD);
+    return;
+  }
+  if (aHTMLInputType.EqualsLiteral("datetime") ||
+      aHTMLInputType.EqualsLiteral("datetime-local")) {
+    aScopes.AppendElement(IS_DATE_FULLDATE);
+    aScopes.AppendElement(IS_TIME_FULLTIME);
+    return;
+  }
+  if (aHTMLInputType.EqualsLiteral("date") ||
+      aHTMLInputType.EqualsLiteral("month") ||
+      aHTMLInputType.EqualsLiteral("week")) {
+    aScopes.AppendElement(IS_DATE_FULLDATE);
+    return;
+  }
+  if (aHTMLInputType.EqualsLiteral("time")) {
+    aScopes.AppendElement(IS_TIME_FULLTIME);
+    return;
+  }
+  if (aHTMLInputType.EqualsLiteral("tel")) {
+    aScopes.AppendElement(IS_TELEPHONE_FULLTELEPHONENUMBER);
+    aScopes.AppendElement(IS_TELEPHONE_LOCALNUMBER);
+    return;
+  }
+  if (aHTMLInputType.EqualsLiteral("number")) {
+    aScopes.AppendElement(IS_NUMBER);
+    return;
+  }
+}
+
+// static
+bool IMEHandler::NeedsSearchInputScope() {
+  return !StaticPrefs::intl_tsf_hack_atok_search_input_scope_disabled() ||
+         !TSFTextStore::IsATOKActive();
+}
+
+// static
+bool IMEHandler::IsOnScreenKeyboardSupported() {
+#ifdef NIGHTLY_BUILD
+  if (FxRWindowManager::GetInstance()->IsFxRWindow(sFocusedWindow)) {
+    return true;
+  }
+#endif  // NIGHTLY_BUILD
+  if (!Preferences::GetBool(kOskEnabled, true) ||
+      !IMEHandler::NeedOnScreenKeyboard()) {
+    return false;
+  }
+
+  // On Windows 11, we ignore tablet mode (see bug 1722208)
+  if (!IsWin11OrLater()) {
+    // On Windows 10 we require tablet mode, unless the user has set the
+    // relevant setting to enable the on-screen keyboard in desktop mode.
+    if (!IsInTabletMode() && !AutoInvokeOnScreenKeyboardInDesktopMode()) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+// static
+void IMEHandler::MaybeShowOnScreenKeyboard(nsWindow* aWindow,
+                                           const InputContext& aInputContext) {
+  if (aInputContext.mHTMLInputMode.EqualsLiteral("none")) {
+    return;
+  }
+
+  if (!IsOnScreenKeyboardSupported()) {
+    return;
+  }
+
+  IMEHandler::ShowOnScreenKeyboard(aWindow);
+}
+
+// static
+void IMEHandler::MaybeDismissOnScreenKeyboard(nsWindow* aWindow, Sync aSync) {
+#ifdef NIGHTLY_BUILD
+  if (FxRWindowManager::GetInstance()->IsFxRWindow(aWindow)) {
+    OSKVRManager::DismissOnScreenKeyboard();
+  }
+#endif  // NIGHTLY_BUILD
+  if (aSync == Sync::Yes) {
+    DismissOnScreenKeyboard(aWindow);
+    return;
+  }
+
+  RefPtr<nsWindow> window(aWindow);
+  NS_DispatchToCurrentThreadQueue(
+      NS_NewRunnableFunction("IMEHandler::MaybeDismissOnScreenKeyboard",
+                             [window]() {
+                               if (window->Destroyed()) {
+                                 return;
+                               }
+                               if (!sFocusedWindow) {
+                                 DismissOnScreenKeyboard(window);
+                               }
+                             }),
+      EventQueuePriority::Idle);
+}
+
+// static
+bool IMEHandler::WStringStartsWithCaseInsensitive(const std::wstring& aHaystack,
+                                                  const std::wstring& aNeedle) {
+  std::wstring lowerCaseHaystack(aHaystack);
+  std::wstring lowerCaseNeedle(aNeedle);
+  std::transform(lowerCaseHaystack.begin(), lowerCaseHaystack.end(),
+                 lowerCaseHaystack.begin(), ::tolower);
+  std::transform(lowerCaseNeedle.begin(), lowerCaseNeedle.end(),
+                 lowerCaseNeedle.begin(), ::tolower);
+  return wcsstr(lowerCaseHaystack.c_str(), lowerCaseNeedle.c_str()) ==
+         lowerCaseHaystack.c_str();
+}
+
+// Returns false if a physical keyboard is detected on Windows 8 and up,
+// or there is some other reason why an onscreen keyboard is not necessary.
+// Returns true if no keyboard is found and this device looks like it needs
+// an on-screen keyboard for text input.
+// static
+bool IMEHandler::NeedOnScreenKeyboard() {
+  if (!Preferences::GetBool(kOskDetectPhysicalKeyboard, true)) {
+    Preferences::SetString(kOskDebugReason, L"IKPOS: Detection disabled.");
+    return true;
+  }
+
+  // If the last focus cause was not user-initiated (ie a result of code
+  // setting focus to an element) then don't auto-show a keyboard. This
+  // avoids cases where the keyboard would pop up "just" because e.g. a
+  // web page chooses to focus a search field on the page, even when that
+  // really isn't what the user is trying to do at that moment.
+  if (!InputContextAction::IsHandlingUserInput(sLastContextActionCause)) {
+    return false;
+  }
+
+  // This function should be only invoked for machines with touch screens.
+  if ((::GetSystemMetrics(SM_DIGITIZER) & NID_INTEGRATED_TOUCH) !=
+      NID_INTEGRATED_TOUCH) {
+    Preferences::SetString(kOskDebugReason, L"IKPOS: Touch screen not found.");
+    return false;
+  }
+
+  // If the device is docked, the user is treating the device as a PC.
+  if (::GetSystemMetrics(SM_SYSTEMDOCKED) != 0) {
+    Preferences::SetString(kOskDebugReason, L"IKPOS: System docked.");
+    return false;
+  }
+
+  // To determine whether a keyboard is present on the device, we do the
+  // following:-
+  // 1. If the platform role is that of a mobile or slate device, check the
+  //    system metric SM_CONVERTIBLESLATEMODE to see if it is being used
+  //    in slate mode. If it is, also check that the last input was a touch.
+  //    If all of this is true, then we should show the on-screen keyboard.
+
+  // 2. If step 1 didn't determine we should show the keyboard, we check if
+  //    this device has keyboards attached to it.
+
+  // Check if the device is being used as a laptop or a tablet. This can be
+  // checked by first checking the role of the device and then the
+  // corresponding system metric (SM_CONVERTIBLESLATEMODE). If it is being
+  // used as a tablet then we want the OSK to show up.
+  if (!sDeterminedPowerPlatformRole) {
+    sDeterminedPowerPlatformRole = true;
+    sPowerPlatformRole = WinUtils::GetPowerPlatformRole();
+  }
+
+  // If this a mobile or slate (tablet) device, check if it is in slate mode.
+  // If the last input was touch, ignore whether or not a keyboard is present.
+  if ((sPowerPlatformRole == PlatformRoleMobile ||
+       sPowerPlatformRole == PlatformRoleSlate) &&
+      ::GetSystemMetrics(SM_CONVERTIBLESLATEMODE) == 0 &&
+      sLastContextActionCause == InputContextAction::CAUSE_TOUCH) {
+    Preferences::SetString(
+        kOskDebugReason,
+        L"IKPOS: Mobile/Slate Platform role, in slate mode with touch event.");
+    return true;
+  }
+
+  return !IMEHandler::IsKeyboardPresentOnSlate();
+}
+
+// Uses the Setup APIs to enumerate the attached keyboards and returns true
+// if the keyboard count is 1 or more. While this will work in most cases
+// it won't work if there are devices which expose keyboard interfaces which
+// are attached to the machine.
+// Based on IsKeyboardPresentOnSlate() in Chromium's base/win/win_util.cc.
+// static
+bool IMEHandler::IsKeyboardPresentOnSlate() {
+  const GUID KEYBOARD_CLASS_GUID = {
+      0x4D36E96B,
+      0xE325,
+      0x11CE,
+      {0xBF, 0xC1, 0x08, 0x00, 0x2B, 0xE1, 0x03, 0x18}};
+
+  // Query for all the keyboard devices.
+  HDEVINFO device_info = ::SetupDiGetClassDevs(&KEYBOARD_CLASS_GUID, nullptr,
+                                               nullptr, DIGCF_PRESENT);
+  if (device_info == INVALID_HANDLE_VALUE) {
+    Preferences::SetString(kOskDebugReason, L"IKPOS: No keyboard info.");
+    return false;
+  }
+
+  // Enumerate all keyboards and look for ACPI\PNP and HID\VID devices. If
+  // the count is more than 1 we assume that a keyboard is present. This is
+  // under the assumption that there will always be one keyboard device.
+  for (DWORD i = 0;; ++i) {
+    SP_DEVINFO_DATA device_info_data = {0};
+    device_info_data.cbSize = sizeof(device_info_data);
+    if (!::SetupDiEnumDeviceInfo(device_info, i, &device_info_data)) {
+      break;
+    }
+
+    // Get the device ID.
+    wchar_t device_id[MAX_DEVICE_ID_LEN];
+    CONFIGRET status = ::CM_Get_Device_ID(device_info_data.DevInst, device_id,
+                                          MAX_DEVICE_ID_LEN, 0);
+    if (status == CR_SUCCESS) {
+      static const std::wstring BT_HID_DEVICE = L"HID\\{00001124";
+      static const std::wstring BT_HOGP_DEVICE = L"HID\\{00001812";
+      // To reduce the scope of the hack we only look for ACPI and HID\\VID
+      // prefixes in the keyboard device ids.
+      if (IMEHandler::WStringStartsWithCaseInsensitive(device_id, L"ACPI") ||
+          IMEHandler::WStringStartsWithCaseInsensitive(device_id,
+                                                       L"HID\\VID") ||
+          IMEHandler::WStringStartsWithCaseInsensitive(device_id,
+                                                       BT_HID_DEVICE) ||
+          IMEHandler::WStringStartsWithCaseInsensitive(device_id,
+                                                       BT_HOGP_DEVICE)) {
+        // The heuristic we are using is to check the count of keyboards and
+        // return true if the API's report one or more keyboards. Please note
+        // that this will break for non keyboard devices which expose a
+        // keyboard PDO.
+        Preferences::SetString(kOskDebugReason,
+                               L"IKPOS: Keyboard presence confirmed.");
+        return true;
+      }
+    }
+  }
+  Preferences::SetString(kOskDebugReason,
+                         L"IKPOS: Lack of keyboard confirmed.");
+  return false;
+}
+
+// static
+bool IMEHandler::IsInTabletMode() {
+  bool isInTabletMode = WindowsUIUtils::GetInTabletMode();
+  if (isInTabletMode) {
+    Preferences::SetString(kOskDebugReason, L"IITM: GetInTabletMode=true.");
+  } else {
+    Preferences::SetString(kOskDebugReason, L"IITM: GetInTabletMode=false.");
+  }
+  return isInTabletMode;
+}
+
+static bool ReadEnableDesktopModeAutoInvoke(uint32_t aRoot,
+                                            nsIWindowsRegKey* aRegKey,
+                                            uint32_t& aValue) {
+  nsresult rv;
+  rv = aRegKey->Open(aRoot, u"SOFTWARE\\Microsoft\\TabletTip\\1.7"_ns,
+                     nsIWindowsRegKey::ACCESS_QUERY_VALUE);
+  if (NS_FAILED(rv)) {
+    Preferences::SetString(kOskDebugReason,
+                           L"AIOSKIDM: failed opening regkey.");
+    return false;
+  }
+  // EnableDesktopModeAutoInvoke is an opt-in option from the Windows
+  // Settings to "Automatically show the touch keyboard in windowed apps
+  // when there's no keyboard attached to your device." If the user has
+  // opted-in to this behavior, the tablet-mode requirement is skipped.
+  rv = aRegKey->ReadIntValue(u"EnableDesktopModeAutoInvoke"_ns, &aValue);
+  if (NS_FAILED(rv)) {
+    Preferences::SetString(kOskDebugReason,
+                           L"AIOSKIDM: failed reading value of regkey.");
+    return false;
+  }
+  return true;
+}
+
+// static
+bool IMEHandler::AutoInvokeOnScreenKeyboardInDesktopMode() {
+  nsresult rv;
+  nsCOMPtr<nsIWindowsRegKey> regKey(
+      do_CreateInstance("@mozilla.org/windows-registry-key;1", &rv));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    Preferences::SetString(kOskDebugReason,
+                           L"AIOSKIDM: "
+                           L"nsIWindowsRegKey not available");
+    return false;
+  }
+
+  uint32_t value;
+  if (!ReadEnableDesktopModeAutoInvoke(nsIWindowsRegKey::ROOT_KEY_CURRENT_USER,
+                                       regKey, value) &&
+      !ReadEnableDesktopModeAutoInvoke(nsIWindowsRegKey::ROOT_KEY_LOCAL_MACHINE,
+                                       regKey, value)) {
+    return false;
+  }
+  if (!!value) {
+    Preferences::SetString(kOskDebugReason, L"AIOSKIDM: regkey value=true.");
+  } else {
+    Preferences::SetString(kOskDebugReason, L"AIOSKIDM: regkey value=false.");
+  }
+  return !!value;
+}
+
+// Based on DisplayVirtualKeyboard() in Chromium's base/win/win_util.cc.
+// static
+void IMEHandler::ShowOnScreenKeyboard(nsWindow* aWindow) {
+#ifdef NIGHTLY_BUILD
+  if (FxRWindowManager::GetInstance()->IsFxRWindow(sFocusedWindow)) {
+    OSKVRManager::ShowOnScreenKeyboard();
+    return;
+  }
+#endif  // NIGHTLY_BUILD
+
+  if (IsWin10AnniversaryUpdateOrLater()) {
+    OSKInputPaneManager::ShowOnScreenKeyboard(aWindow->GetWindowHandle());
+    return;
+  }
+
+  OSKTabTipManager::ShowOnScreenKeyboard();
+}
+
+// Based on DismissVirtualKeyboard() in Chromium's base/win/win_util.cc.
+// static
+void IMEHandler::DismissOnScreenKeyboard(nsWindow* aWindow) {
+  // Dismiss the virtual keyboard if it's open
+  if (IsWin10AnniversaryUpdateOrLater()) {
+    OSKInputPaneManager::DismissOnScreenKeyboard(aWindow->GetWindowHandle());
+    return;
+  }
+
+  OSKTabTipManager::DismissOnScreenKeyboard();
+}
+
+bool IMEHandler::MaybeCreateNativeCaret(nsWindow* aWindow) {
+  MOZ_ASSERT(aWindow);
+
+  if (IsA11yHandlingNativeCaret()) {
+    return false;
+  }
+
+  if (!sHasNativeCaretBeenRequested) {
+    // If we have not received WM_GETOBJECT for OBJID_CARET, there may be new
+    // application which requires our caret information.  For kicking its
+    // window event proc, we should fire a window event here.
+    // (If there is such application, sHasNativeCaretBeenRequested will be set
+    // to true later.)
+    // FYI: If we create native caret and move its position, native caret
+    //      causes EVENT_OBJECT_LOCATIONCHANGE event with OBJID_CARET and
+    //      OBJID_CLIENT.
+    ::NotifyWinEvent(EVENT_OBJECT_LOCATIONCHANGE, aWindow->GetWindowHandle(),
+                     OBJID_CARET, OBJID_CLIENT);
+    return false;
+  }
+
+  MaybeDestroyNativeCaret();
+
+  // If focused content is not text editable, we don't support caret
+  // caret information without a11y module.
+  if (!aWindow->GetInputContext().mIMEState.IsEditable()) {
+    return false;
+  }
+
+  WidgetQueryContentEvent queryCaretRectEvent(true, eQueryCaretRect, aWindow);
+  aWindow->InitEvent(queryCaretRectEvent);
+
+  WidgetQueryContentEvent::Options options;
+  options.mRelativeToInsertionPoint = true;
+  queryCaretRectEvent.InitForQueryCaretRect(0, options);
+
+  aWindow->DispatchWindowEvent(queryCaretRectEvent);
+  if (NS_WARN_IF(queryCaretRectEvent.Failed())) {
+    return false;
+  }
+
+  return CreateNativeCaret(aWindow, queryCaretRectEvent.mReply->mRect);
+}
+
+bool IMEHandler::CreateNativeCaret(nsWindow* aWindow,
+                                   const LayoutDeviceIntRect& aCaretRect) {
+  MOZ_ASSERT(aWindow);
+
+  MOZ_ASSERT(!IsA11yHandlingNativeCaret());
+
+  sNativeCaretIsCreated =
+      ::CreateCaret(aWindow->GetWindowHandle(), nullptr, aCaretRect.Width(),
+                    aCaretRect.Height());
+  if (!sNativeCaretIsCreated) {
+    return false;
+  }
+  nsWindow* toplevelWindow = aWindow->GetTopLevelWindow(false);
+  if (NS_WARN_IF(!toplevelWindow)) {
+    MaybeDestroyNativeCaret();
+    return false;
+  }
+
+  LayoutDeviceIntPoint caretPosition(aCaretRect.TopLeft());
+  if (toplevelWindow != aWindow) {
+    caretPosition += toplevelWindow->WidgetToScreenOffset();
+    caretPosition -= aWindow->WidgetToScreenOffset();
+  }
+
+  ::SetCaretPos(caretPosition.x, caretPosition.y);
+  return true;
+}
+
+void IMEHandler::MaybeDestroyNativeCaret() {
+  if (!sNativeCaretIsCreated) {
+    return;
+  }
+  ::DestroyCaret();
+  sNativeCaretIsCreated = false;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/WinIMEHandler.h b/widget/windows/WinIMEHandler.h
new file mode 100644
index 0000000000..410e1ebd22
--- /dev/null
+++ b/widget/windows/WinIMEHandler.h
@@ -0,0 +1,247 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WinIMEHandler_h_
+#define WinIMEHandler_h_
+
+#include "nscore.h"
+#include "nsWindow.h"
+#include "npapi.h"
+#include <windows.h>
+#include <inputscope.h>
+
+#define NS_WM_IMEFIRST WM_IME_SETCONTEXT
+#define NS_WM_IMELAST WM_IME_KEYUP
+
+class nsWindow;
+
+namespace mozilla {
+namespace widget {
+
+struct MSGResult;
+
+/**
+ * IMEHandler class is a mediator class.  On Windows, there are two IME API
+ * sets: One is IMM which is legacy API set. The other is TSF which is modern
+ * API set. By using this class, non-IME handler classes don't need to worry
+ * that we're in which mode.
+ */
+class IMEHandler final {
+ private:
+  /**
+   * Initialize() initializes both TSF modules and IMM modules.  Some TIPs
+   * may require a normal window (i.e., not message window) belonging to
+   * this process.  Therefore, this is called immediately after first normal
+   * window is created.
+   */
+  static void Initialize();
+
+ public:
+  static void Terminate();
+
+  /**
+   * Returns TSF related native data or native IME context.
+   */
+  static void* GetNativeData(nsWindow* aWindow, uint32_t aDataType);
+
+  /**
+   * ProcessRawKeyMessage() message is called before calling TranslateMessage()
+   * and DispatchMessage().  If this returns true, the message is consumed.
+   * Then, caller must not perform TranslateMessage() nor DispatchMessage().
+   */
+  static bool ProcessRawKeyMessage(const MSG& aMsg);
+
+  /**
+   * When the message is not needed to handle anymore by the caller, this
+   * returns true.  Otherwise, false.
+   */
+  static bool ProcessMessage(nsWindow* aWindow, UINT aMessage, WPARAM& aWParam,
+                             LPARAM& aLParam, MSGResult& aResult);
+
+  /**
+   * IsA11yHandlingNativeCaret() returns true if a11y is handling
+   * native caret.  In such case, IME modules shouldn't touch native caret.
+   **/
+  static bool IsA11yHandlingNativeCaret();
+
+  /**
+   * NeedsToCreateNativeCaret() returns true if IME handler needs to create
+   * native caret for other applications which requests OBJID_CARET with
+   * WM_GETOBJECT and a11y module isn't active (if a11y module is active,
+   * it always creates native caret, i.e., even if no editor has focus).
+   */
+  static bool NeedsToCreateNativeCaret() {
+    return sHasNativeCaretBeenRequested && !IsA11yHandlingNativeCaret();
+  }
+
+  /**
+   * CreateNativeCaret() create native caret if this has been created it.
+   *
+   * @param aWindow     The window which owns the caret.
+   * @param aCaretRect  The caret rect relative to aWindow.
+   */
+  static bool CreateNativeCaret(nsWindow* aWindow,
+                                const LayoutDeviceIntRect& aCaretRect);
+
+  /**
+   * MaybeDestroyNativeCaret() destroies native caret if it has been created
+   * by IMEHandler.
+   */
+  static void MaybeDestroyNativeCaret();
+
+  /**
+   * HasNativeCaret() returns true if there is native caret and it was created
+   * by IMEHandler.
+   */
+  static bool HasNativeCaret() { return sNativeCaretIsCreated; }
+
+  /**
+   * When there is a composition, returns true.  Otherwise, false.
+   */
+  static bool IsComposing();
+
+  /**
+   * When there is a composition and it's in the window, returns true.
+   * Otherwise, false.
+   */
+  static bool IsComposingOn(nsWindow* aWindow);
+
+  /**
+   * Notifies IME of the notification (a request or an event).
+   */
+  static nsresult NotifyIME(nsWindow* aWindow,
+                            const IMENotification& aIMENotification);
+
+  /**
+   * Returns notification requests of IME.
+   */
+  static IMENotificationRequests GetIMENotificationRequests();
+
+  /**
+   * Returns native text event dispatcher listener.
+   */
+  static TextEventDispatcherListener* GetNativeTextEventDispatcherListener();
+
+  /**
+   * Returns IME open state on the window.
+   */
+  static bool GetOpenState(nsWindow* aWindow);
+
+  /**
+   * Called when the window is destroying.
+   */
+  static void OnDestroyWindow(nsWindow* aWindow);
+
+  /**
+   * Called when nsIWidget::SetInputContext() is called before the window's
+   * InputContext is modified actually.
+   */
+  static void SetInputContext(nsWindow* aWindow, InputContext& aInputContext,
+                              const InputContextAction& aAction);
+
+  /**
+   * Associate or disassociate IME context to/from the aWindowBase.
+   */
+  static void AssociateIMEContext(nsWindow* aWindowBase, bool aEnable);
+
+  /**
+   * Called when the window is created.
+   */
+  static void InitInputContext(nsWindow* aWindow, InputContext& aInputContext);
+
+  /**
+   * This is called by TSFStaticSink when active IME is changed.
+   */
+  static void OnKeyboardLayoutChanged();
+
+#ifdef DEBUG
+  /**
+   * Returns true when current keyboard layout has IME.  Otherwise, false.
+   */
+  static bool CurrentKeyboardLayoutHasIME();
+#endif  // #ifdef DEBUG
+
+  /**
+   * Append InputScope values from inputmode string.
+   */
+  static void AppendInputScopeFromInputMode(const nsAString& aHTMLInputMode,
+                                            nsTArray<InputScope>& aScopes);
+
+  /**
+   * Append InputScope values from type attreibute string of input element
+   */
+  static void AppendInputScopeFromType(const nsAString& aInputType,
+                                       nsTArray<InputScope>& aScopes);
+
+  /**
+   * Return focused window if this receives focus notification and has not
+   * received blur notification yet.
+   */
+  static nsWindow* GetFocusedWindow() { return sFocusedWindow; }
+
+ private:
+  static nsWindow* sFocusedWindow;
+  static InputContextAction::Cause sLastContextActionCause;
+
+  static bool sMaybeEditable;
+  static bool sForceDisableCurrentIMM_IME;
+  static bool sNativeCaretIsCreated;
+  static bool sHasNativeCaretBeenRequested;
+
+  /**
+   * MaybeCreateNativeCaret() may create native caret over our caret if
+   * focused content is text editable and we need to create native caret
+   * for other applications.
+   *
+   * @param aWindow     The window which owns the native caret.
+   */
+  static bool MaybeCreateNativeCaret(nsWindow* aWindow);
+
+  static decltype(SetInputScopes)* sSetInputScopes;
+  static void SetInputScopeForIMM32(nsWindow* aWindow,
+                                    const nsAString& aHTMLInputType,
+                                    const nsAString& aHTMLInputMode,
+                                    bool aInPrivateBrowsing);
+  static bool sIsInTSFMode;
+  // If sIMMEnabled is false, any IME messages are not handled in TSF mode.
+  // Additionally, IME context is always disassociated from focused window.
+  static bool sIsIMMEnabled;
+
+  static bool IsTSFAvailable() { return sIsInTSFMode; }
+  static bool IsIMMActive();
+
+  static bool IsOnScreenKeyboardSupported();
+
+  static void MaybeShowOnScreenKeyboard(nsWindow* aWindow,
+                                        const InputContext& aInputContext);
+  enum class Sync { Yes, No };
+  static void MaybeDismissOnScreenKeyboard(nsWindow* aWindow,
+                                           Sync aSync = Sync::No);
+  static bool WStringStartsWithCaseInsensitive(const std::wstring& aHaystack,
+                                               const std::wstring& aNeedle);
+  static bool NeedOnScreenKeyboard();
+  static bool IsKeyboardPresentOnSlate();
+  static bool IsInTabletMode();
+  static bool AutoInvokeOnScreenKeyboardInDesktopMode();
+  static bool NeedsToAssociateIMC();
+  static bool NeedsSearchInputScope();
+
+  /**
+   * Show the Windows on-screen keyboard. Only allowed for
+   * chrome documents and Windows 8 and higher.
+   */
+  static void ShowOnScreenKeyboard(nsWindow* aWindow);
+
+  /**
+   * Dismiss the Windows on-screen keyboard. Only allowed for
+   * Windows 8 and higher.
+   */
+  static void DismissOnScreenKeyboard(nsWindow* aWindow);
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // #ifndef WinIMEHandler_h_
diff --git a/widget/windows/WinMessages.h b/widget/windows/WinMessages.h
new file mode 100644
index 0000000000..8c90460e8e
--- /dev/null
+++ b/widget/windows/WinMessages.h
@@ -0,0 +1,93 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_WinMessages_h_
+#define mozilla_widget_WinMessages_h_
+
+/*****************************************************************************
+ * MOZ_WM_* messages
+ ****************************************************************************/
+
+// A magic APP message that can be sent to quit, sort of like a
+// QUERYENDSESSION/ENDSESSION, but without the query.
+#define MOZ_WM_APP_QUIT (WM_APP + 0x0300)
+// Used as a "tracer" event to probe event loop latency.
+#define MOZ_WM_TRACE (WM_APP + 0x0301)
+// accessibility priming
+#define MOZ_WM_STARTA11Y (WM_APP + 0x0302)
+// Our internal message for WM_MOUSEWHEEL, WM_MOUSEHWHEEL, WM_VSCROLL and
+// WM_HSCROLL
+#define MOZ_WM_MOUSEVWHEEL (WM_APP + 0x0310)
+#define MOZ_WM_MOUSEHWHEEL (WM_APP + 0x0311)
+#define MOZ_WM_VSCROLL (WM_APP + 0x0312)
+#define MOZ_WM_HSCROLL (WM_APP + 0x0313)
+#define MOZ_WM_MOUSEWHEEL_FIRST MOZ_WM_MOUSEVWHEEL
+#define MOZ_WM_MOUSEWHEEL_LAST MOZ_WM_HSCROLL
+// If a popup window is being activated, we try to reactivate the previous
+// window with this message.
+#define MOZ_WM_REACTIVATE (WM_APP + 0x0314)
+// If TSFTextStore needs to notify TSF/TIP of layout change later, this
+// message is posted.
+#define MOZ_WM_NOTIY_TSF_OF_LAYOUT_CHANGE (WM_APP + 0x0315)
+// Internal message used in correcting backwards clock skew
+#define MOZ_WM_SKEWFIX (WM_APP + 0x0316)
+// Internal message used for rolling up popups for dmanip events
+#define MOZ_WM_DMANIP (WM_APP + 0x0317)
+
+// Internal message used to work around race condition in explorer.exe's
+// fullscreen window-state update handler in Windows 10+. (See bug 1835851.)
+#define MOZ_WM_FULLSCREEN_STATE_UPDATE (WM_APP + 0x0318)
+
+// XXX Should rename them to MOZ_WM_* and use safer values!
+// Messages for fullscreen transition window
+#define WM_FULLSCREEN_TRANSITION_BEFORE (WM_USER + 0)
+#define WM_FULLSCREEN_TRANSITION_AFTER (WM_USER + 1)
+
+#ifndef APPCOMMAND_BROWSER_BACKWARD
+#  define APPCOMMAND_BROWSER_BACKWARD 1
+#  define APPCOMMAND_BROWSER_FORWARD 2
+#  define APPCOMMAND_BROWSER_REFRESH 3
+#  define APPCOMMAND_BROWSER_STOP 4
+#  define APPCOMMAND_BROWSER_SEARCH 5
+#  define APPCOMMAND_BROWSER_FAVORITES 6
+#  define APPCOMMAND_BROWSER_HOME 7
+
+#  define APPCOMMAND_MEDIA_NEXTTRACK 11
+#  define APPCOMMAND_MEDIA_PREVIOUSTRACK 12
+#  define APPCOMMAND_MEDIA_STOP 13
+#  define APPCOMMAND_MEDIA_PLAY_PAUSE 14
+
+/*
+ * Additional commands currently not in use.
+ *
+ *#define APPCOMMAND_VOLUME_MUTE            8
+ *#define APPCOMMAND_VOLUME_DOWN            9
+ *#define APPCOMMAND_VOLUME_UP              10
+ *#define APPCOMMAND_LAUNCH_MAIL            15
+ *#define APPCOMMAND_LAUNCH_MEDIA_SELECT    16
+ *#define APPCOMMAND_LAUNCH_APP1            17
+ *#define APPCOMMAND_LAUNCH_APP2            18
+ *#define APPCOMMAND_BASS_DOWN              19
+ *#define APPCOMMAND_BASS_BOOST             20
+ *#define APPCOMMAND_BASS_UP                21
+ *#define APPCOMMAND_TREBLE_DOWN            22
+ *#define APPCOMMAND_TREBLE_UP              23
+ *#define FAPPCOMMAND_MOUSE                 0x8000
+ *#define FAPPCOMMAND_KEY                   0
+ *#define FAPPCOMMAND_OEM                   0x1000
+ */
+
+#  define GET_APPCOMMAND_LPARAM(lParam) \
+    ((short)(HIWORD(lParam) & ~FAPPCOMMAND_MASK))
+
+/*
+ *#define GET_DEVICE_LPARAM(lParam)         ((WORD)(HIWORD(lParam) &
+ *FAPPCOMMAND_MASK)) #define GET_MOUSEORKEY_LPARAM             GET_DEVICE_LPARAM
+ *#define GET_FLAGS_LPARAM(lParam)          (LOWORD(lParam))
+ *#define GET_KEYSTATE_LPARAM(lParam)       GET_FLAGS_LPARAM(lParam)
+ */
+#endif  // #ifndef APPCOMMAND_BROWSER_BACKWARD
+
+#endif  // #ifndef mozilla_widget_WinMessages_h_
diff --git a/widget/windows/WinModifierKeyState.h b/widget/windows/WinModifierKeyState.h
new file mode 100644
index 0000000000..0788c25939
--- /dev/null
+++ b/widget/windows/WinModifierKeyState.h
@@ -0,0 +1,59 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_WinModifierKeyState_h_
+#define mozilla_widget_WinModifierKeyState_h_
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/EventForwards.h"
+#include "nsStringFwd.h"
+#include <windows.h>
+
+namespace mozilla {
+namespace widget {
+
+class MOZ_STACK_CLASS ModifierKeyState final {
+ public:
+  ModifierKeyState();
+  explicit ModifierKeyState(Modifiers aModifiers);
+
+  void Update();
+
+  void Unset(Modifiers aRemovingModifiers);
+  void Set(Modifiers aAddingModifiers);
+
+  void InitInputEvent(WidgetInputEvent& aInputEvent) const;
+
+  // Do not create IsAltGr() because it's unclear whether:
+  // - AltGr key is actually pressed.
+  // - Both Ctrl and Alt keys are pressed when a keyboard layout which
+  //   has AltGr key.
+  // - Both Ctrl and Alt keys are pressed when a keyboard layout which
+  //   does not have AltGr key.
+  bool IsShift() const;
+  bool IsControl() const;
+  bool IsAlt() const;
+  bool IsWin() const;
+
+  bool MaybeMatchShortcutKey() const;
+
+  bool IsCapsLocked() const;
+  bool IsNumLocked() const;
+  bool IsScrollLocked() const;
+
+  MOZ_ALWAYS_INLINE Modifiers GetModifiers() const { return mModifiers; }
+
+ private:
+  Modifiers mModifiers;
+
+  void InitMouseEvent(WidgetInputEvent& aMouseEvent) const;
+};
+
+const nsCString ToString(const ModifierKeyState& aModifierKeyState);
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // #ifndef mozilla_widget_WinModifierKeyState_h_
diff --git a/widget/windows/WinMouseScrollHandler.cpp b/widget/windows/WinMouseScrollHandler.cpp
new file mode 100644
index 0000000000..e10f7b29dc
--- /dev/null
+++ b/widget/windows/WinMouseScrollHandler.cpp
@@ -0,0 +1,1634 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/DebugOnly.h"
+
+#include "mozilla/Logging.h"
+
+#include "WinMouseScrollHandler.h"
+#include "nsWindow.h"
+#include "nsWindowDefs.h"
+#include "KeyboardLayout.h"
+#include "WinUtils.h"
+#include "nsGkAtoms.h"
+#include "nsIDOMWindowUtils.h"
+
+#include "mozilla/MiscEvents.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/dom/WheelEventBinding.h"
+#include "mozilla/StaticPrefs_mousewheel.h"
+#include "mozilla/widget/WinRegistry.h"
+
+#include <psapi.h>
+
+namespace mozilla {
+namespace widget {
+
+LazyLogModule gMouseScrollLog("MouseScrollHandlerWidgets");
+
+static const char* GetBoolName(bool aBool) { return aBool ? "TRUE" : "FALSE"; }
+
+MouseScrollHandler* MouseScrollHandler::sInstance = nullptr;
+
+bool MouseScrollHandler::Device::sFakeScrollableWindowNeeded = false;
+
+bool MouseScrollHandler::Device::SynTP::sInitialized = false;
+int32_t MouseScrollHandler::Device::SynTP::sMajorVersion = 0;
+int32_t MouseScrollHandler::Device::SynTP::sMinorVersion = -1;
+
+bool MouseScrollHandler::Device::Elantech::sUseSwipeHack = false;
+bool MouseScrollHandler::Device::Elantech::sUsePinchHack = false;
+DWORD MouseScrollHandler::Device::Elantech::sZoomUntil = 0;
+
+bool MouseScrollHandler::Device::Apoint::sInitialized = false;
+int32_t MouseScrollHandler::Device::Apoint::sMajorVersion = 0;
+int32_t MouseScrollHandler::Device::Apoint::sMinorVersion = -1;
+
+bool MouseScrollHandler::Device::SetPoint::sMightBeUsing = false;
+
+// The duration until timeout of events transaction.  The value is 1.5 sec,
+// it's just a magic number, it was suggested by Logitech's engineer, see
+// bug 605648 comment 90.
+#define DEFAULT_TIMEOUT_DURATION 1500
+
+/******************************************************************************
+ *
+ * MouseScrollHandler
+ *
+ ******************************************************************************/
+
+/* static */
+POINTS
+MouseScrollHandler::GetCurrentMessagePos() {
+  if (SynthesizingEvent::IsSynthesizing()) {
+    return sInstance->mSynthesizingEvent->GetCursorPoint();
+  }
+  DWORD pos = ::GetMessagePos();
+  return MAKEPOINTS(pos);
+}
+
+// Get rid of the GetMessagePos() API.
+#define GetMessagePos()
+
+/* static */
+void MouseScrollHandler::Initialize() { Device::Init(); }
+
+/* static */
+void MouseScrollHandler::Shutdown() {
+  delete sInstance;
+  sInstance = nullptr;
+}
+
+/* static */
+MouseScrollHandler* MouseScrollHandler::GetInstance() {
+  if (!sInstance) {
+    sInstance = new MouseScrollHandler();
+  }
+  return sInstance;
+}
+
+MouseScrollHandler::MouseScrollHandler()
+    : mIsWaitingInternalMessage(false), mSynthesizingEvent(nullptr) {
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScroll: Creating an instance, this=%p, sInstance=%p", this,
+           sInstance));
+}
+
+MouseScrollHandler::~MouseScrollHandler() {
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScroll: Destroying an instance, this=%p, sInstance=%p", this,
+           sInstance));
+
+  delete mSynthesizingEvent;
+}
+
+/* static */
+void MouseScrollHandler::MaybeLogKeyState() {
+  if (!MOZ_LOG_TEST(gMouseScrollLog, LogLevel::Debug)) {
+    return;
+  }
+  BYTE keyboardState[256];
+  if (::GetKeyboardState(keyboardState)) {
+    for (size_t i = 0; i < ArrayLength(keyboardState); i++) {
+      if (keyboardState[i]) {
+        MOZ_LOG(gMouseScrollLog, LogLevel::Debug,
+                ("    Current key state: keyboardState[0x%02zX]=0x%02X (%s)", i,
+                 keyboardState[i],
+                 ((keyboardState[i] & 0x81) == 0x81) ? "Pressed and Toggled"
+                 : (keyboardState[i] & 0x80)         ? "Pressed"
+                 : (keyboardState[i] & 0x01)         ? "Toggled"
+                                                     : "Unknown"));
+      }
+    }
+  } else {
+    MOZ_LOG(
+        gMouseScrollLog, LogLevel::Debug,
+        ("MouseScroll::MaybeLogKeyState(): Failed to print current keyboard "
+         "state"));
+  }
+}
+
+/* static */
+bool MouseScrollHandler::NeedsMessage(UINT aMsg) {
+  switch (aMsg) {
+    case WM_SETTINGCHANGE:
+    case WM_MOUSEWHEEL:
+    case WM_MOUSEHWHEEL:
+    case WM_HSCROLL:
+    case WM_VSCROLL:
+    case MOZ_WM_MOUSEVWHEEL:
+    case MOZ_WM_MOUSEHWHEEL:
+    case MOZ_WM_HSCROLL:
+    case MOZ_WM_VSCROLL:
+    case WM_KEYDOWN:
+    case WM_KEYUP:
+      return true;
+  }
+  return false;
+}
+
+/* static */
+bool MouseScrollHandler::ProcessMessage(nsWindow* aWidget, UINT msg,
+                                        WPARAM wParam, LPARAM lParam,
+                                        MSGResult& aResult) {
+  Device::Elantech::UpdateZoomUntil();
+
+  switch (msg) {
+    case WM_SETTINGCHANGE:
+      if (!sInstance) {
+        return false;
+      }
+      if (wParam == SPI_SETWHEELSCROLLLINES ||
+          wParam == SPI_SETWHEELSCROLLCHARS) {
+        sInstance->mSystemSettings.MarkDirty();
+      }
+      return false;
+
+    case WM_MOUSEWHEEL:
+    case WM_MOUSEHWHEEL:
+      GetInstance()->ProcessNativeMouseWheelMessage(aWidget, msg, wParam,
+                                                    lParam);
+      sInstance->mSynthesizingEvent->NotifyNativeMessageHandlingFinished();
+      // We don't need to call next wndproc for WM_MOUSEWHEEL and
+      // WM_MOUSEHWHEEL.  We should consume them always.  If the messages
+      // would be handled by our window again, it caused making infinite
+      // message loop.
+      aResult.mConsumed = true;
+      aResult.mResult = (msg != WM_MOUSEHWHEEL);
+      return true;
+
+    case WM_HSCROLL:
+    case WM_VSCROLL:
+      aResult.mConsumed = GetInstance()->ProcessNativeScrollMessage(
+          aWidget, msg, wParam, lParam);
+      sInstance->mSynthesizingEvent->NotifyNativeMessageHandlingFinished();
+      aResult.mResult = 0;
+      return true;
+
+    case MOZ_WM_MOUSEVWHEEL:
+    case MOZ_WM_MOUSEHWHEEL:
+      GetInstance()->HandleMouseWheelMessage(aWidget, msg, wParam, lParam);
+      sInstance->mSynthesizingEvent->NotifyInternalMessageHandlingFinished();
+      // Doesn't need to call next wndproc for internal wheel message.
+      aResult.mConsumed = true;
+      return true;
+
+    case MOZ_WM_HSCROLL:
+    case MOZ_WM_VSCROLL:
+      GetInstance()->HandleScrollMessageAsMouseWheelMessage(aWidget, msg,
+                                                            wParam, lParam);
+      sInstance->mSynthesizingEvent->NotifyInternalMessageHandlingFinished();
+      // Doesn't need to call next wndproc for internal scroll message.
+      aResult.mConsumed = true;
+      return true;
+
+    case WM_KEYDOWN:
+    case WM_KEYUP:
+      MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+              ("MouseScroll::ProcessMessage(): aWidget=%p, "
+               "msg=%s(0x%04X), wParam=0x%02zX, ::GetMessageTime()=%ld",
+               aWidget,
+               msg == WM_KEYDOWN ? "WM_KEYDOWN"
+               : msg == WM_KEYUP ? "WM_KEYUP"
+                                 : "Unknown",
+               msg, wParam, ::GetMessageTime()));
+      MaybeLogKeyState();
+      if (Device::Elantech::HandleKeyMessage(aWidget, msg, wParam, lParam)) {
+        aResult.mResult = 0;
+        aResult.mConsumed = true;
+        return true;
+      }
+      return false;
+
+    default:
+      return false;
+  }
+}
+
+/* static */
+nsresult MouseScrollHandler::SynthesizeNativeMouseScrollEvent(
+    nsWindow* aWidget, const LayoutDeviceIntPoint& aPoint,
+    uint32_t aNativeMessage, int32_t aDelta, uint32_t aModifierFlags,
+    uint32_t aAdditionalFlags) {
+  bool useFocusedWindow = !(
+      aAdditionalFlags & nsIDOMWindowUtils::MOUSESCROLL_PREFER_WIDGET_AT_POINT);
+
+  POINT pt;
+  pt.x = aPoint.x;
+  pt.y = aPoint.y;
+
+  HWND target = useFocusedWindow ? ::WindowFromPoint(pt) : ::GetFocus();
+  NS_ENSURE_TRUE(target, NS_ERROR_FAILURE);
+
+  WPARAM wParam = 0;
+  LPARAM lParam = 0;
+  switch (aNativeMessage) {
+    case WM_MOUSEWHEEL:
+    case WM_MOUSEHWHEEL: {
+      lParam = MAKELPARAM(pt.x, pt.y);
+      WORD mod = 0;
+      if (aModifierFlags & (nsIWidget::CTRL_L | nsIWidget::CTRL_R)) {
+        mod |= MK_CONTROL;
+      }
+      if (aModifierFlags & (nsIWidget::SHIFT_L | nsIWidget::SHIFT_R)) {
+        mod |= MK_SHIFT;
+      }
+      wParam = MAKEWPARAM(mod, aDelta);
+      break;
+    }
+    case WM_VSCROLL:
+    case WM_HSCROLL:
+      lParam = (aAdditionalFlags &
+                nsIDOMWindowUtils::MOUSESCROLL_WIN_SCROLL_LPARAM_NOT_NULL)
+                   ? reinterpret_cast<LPARAM>(target)
+                   : 0;
+      wParam = aDelta;
+      break;
+    default:
+      return NS_ERROR_INVALID_ARG;
+  }
+
+  // Ensure to make the instance.
+  GetInstance();
+
+  BYTE kbdState[256];
+  memset(kbdState, 0, sizeof(kbdState));
+
+  AutoTArray<KeyPair, 10> keySequence;
+  WinUtils::SetupKeyModifiersSequence(&keySequence, aModifierFlags,
+                                      aNativeMessage);
+
+  for (uint32_t i = 0; i < keySequence.Length(); ++i) {
+    uint8_t key = keySequence[i].mGeneral;
+    uint8_t keySpecific = keySequence[i].mSpecific;
+    kbdState[key] = 0x81;  // key is down and toggled on if appropriate
+    if (keySpecific) {
+      kbdState[keySpecific] = 0x81;
+    }
+  }
+
+  if (!sInstance->mSynthesizingEvent) {
+    sInstance->mSynthesizingEvent = new SynthesizingEvent();
+  }
+
+  POINTS pts;
+  pts.x = static_cast<SHORT>(pt.x);
+  pts.y = static_cast<SHORT>(pt.y);
+  return sInstance->mSynthesizingEvent->Synthesize(pts, target, aNativeMessage,
+                                                   wParam, lParam, kbdState);
+}
+
+/* static */
+void MouseScrollHandler::InitEvent(nsWindow* aWidget, WidgetGUIEvent& aEvent,
+                                   LPARAM* aPoint) {
+  NS_ENSURE_TRUE_VOID(aWidget);
+
+  // If a point is provided, use it; otherwise, get current message point or
+  // synthetic point
+  POINTS pointOnScreen;
+  if (aPoint != nullptr) {
+    pointOnScreen = MAKEPOINTS(*aPoint);
+  } else {
+    pointOnScreen = GetCurrentMessagePos();
+  }
+
+  // InitEvent expects the point to be in window coordinates, so translate the
+  // point from screen coordinates.
+  POINT pointOnWindow;
+  POINTSTOPOINT(pointOnWindow, pointOnScreen);
+  ::ScreenToClient(aWidget->GetWindowHandle(), &pointOnWindow);
+
+  LayoutDeviceIntPoint point;
+  point.x = pointOnWindow.x;
+  point.y = pointOnWindow.y;
+
+  aWidget->InitEvent(aEvent, &point);
+}
+
+/* static */
+ModifierKeyState MouseScrollHandler::GetModifierKeyState(UINT aMessage) {
+  ModifierKeyState result;
+  // Assume the Control key is down if the Elantech touchpad has sent the
+  // mis-ordered WM_KEYDOWN/WM_MOUSEWHEEL messages.  (See the comment in
+  // MouseScrollHandler::Device::Elantech::HandleKeyMessage().)
+  if ((aMessage == MOZ_WM_MOUSEVWHEEL || aMessage == WM_MOUSEWHEEL) &&
+      !result.IsControl() && Device::Elantech::IsZooming()) {
+    // XXX Do we need to unset MODIFIER_SHIFT, MODIFIER_ALT, MODIFIER_META too?
+    //     If one of them are true, the default action becomes not zooming.
+    result.Unset(MODIFIER_ALTGRAPH);
+    result.Set(MODIFIER_CONTROL);
+  }
+  return result;
+}
+
+POINT
+MouseScrollHandler::ComputeMessagePos(UINT aMessage, WPARAM aWParam,
+                                      LPARAM aLParam) {
+  POINT point;
+  if (Device::SetPoint::IsGetMessagePosResponseValid(aMessage, aWParam,
+                                                     aLParam)) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::ComputeMessagePos: Using ::GetCursorPos()"));
+    ::GetCursorPos(&point);
+  } else {
+    POINTS pts = GetCurrentMessagePos();
+    point.x = pts.x;
+    point.y = pts.y;
+  }
+  return point;
+}
+
+void MouseScrollHandler::ProcessNativeMouseWheelMessage(nsWindow* aWidget,
+                                                        UINT aMessage,
+                                                        WPARAM aWParam,
+                                                        LPARAM aLParam) {
+  if (SynthesizingEvent::IsSynthesizing()) {
+    mSynthesizingEvent->NativeMessageReceived(aWidget, aMessage, aWParam,
+                                              aLParam);
+  }
+
+  POINT point = ComputeMessagePos(aMessage, aWParam, aLParam);
+
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScroll::ProcessNativeMouseWheelMessage: aWidget=%p, "
+           "aMessage=%s, wParam=0x%08zX, lParam=0x%08" PRIXLPTR
+           ", point: { x=%ld, y=%ld }",
+           aWidget,
+           aMessage == WM_MOUSEWHEEL    ? "WM_MOUSEWHEEL"
+           : aMessage == WM_MOUSEHWHEEL ? "WM_MOUSEHWHEEL"
+           : aMessage == WM_VSCROLL     ? "WM_VSCROLL"
+                                        : "WM_HSCROLL",
+           aWParam, aLParam, point.x, point.y));
+  MaybeLogKeyState();
+
+  HWND underCursorWnd = ::WindowFromPoint(point);
+  if (!underCursorWnd) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::ProcessNativeMouseWheelMessage: "
+             "No window is not found under the cursor"));
+    return;
+  }
+
+  if (Device::Elantech::IsPinchHackNeeded() &&
+      Device::Elantech::IsHelperWindow(underCursorWnd)) {
+    // The Elantech driver places a window right underneath the cursor
+    // when sending a WM_MOUSEWHEEL event to us as part of a pinch-to-zoom
+    // gesture.  We detect that here, and search for our window that would
+    // be beneath the cursor if that window wasn't there.
+    underCursorWnd = WinUtils::FindOurWindowAtPoint(point);
+    if (!underCursorWnd) {
+      MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+              ("MouseScroll::ProcessNativeMouseWheelMessage: "
+               "Our window is not found under the Elantech helper window"));
+      return;
+    }
+  }
+
+  // Handle most cases first.  If the window under mouse cursor is our window
+  // except plugin window (MozillaWindowClass), we should handle the message
+  // on the window.
+  if (WinUtils::IsOurProcessWindow(underCursorWnd)) {
+    nsWindow* destWindow = WinUtils::GetNSWindowPtr(underCursorWnd);
+    if (!destWindow) {
+      MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+              ("MouseScroll::ProcessNativeMouseWheelMessage: "
+               "Found window under the cursor isn't managed by nsWindow..."));
+      HWND wnd = ::GetParent(underCursorWnd);
+      for (; wnd; wnd = ::GetParent(wnd)) {
+        destWindow = WinUtils::GetNSWindowPtr(wnd);
+        if (destWindow) {
+          break;
+        }
+      }
+      if (!wnd) {
+        MOZ_LOG(
+            gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::ProcessNativeMouseWheelMessage: Our window which is "
+             "managed by nsWindow is not found under the cursor"));
+        return;
+      }
+    }
+
+    MOZ_ASSERT(destWindow, "destWindow must not be NULL");
+
+    // Some odd touchpad utils sets focus to window under the mouse cursor.
+    // this emulates the odd behavior for debug.
+    if (mUserPrefs.ShouldEmulateToMakeWindowUnderCursorForeground() &&
+        (aMessage == WM_MOUSEWHEEL || aMessage == WM_MOUSEHWHEEL) &&
+        ::GetForegroundWindow() != destWindow->GetWindowHandle()) {
+      ::SetForegroundWindow(destWindow->GetWindowHandle());
+    }
+
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::ProcessNativeMouseWheelMessage: Succeeded, "
+             "Posting internal message to an nsWindow (%p)...",
+             destWindow));
+    mIsWaitingInternalMessage = true;
+    UINT internalMessage = WinUtils::GetInternalMessage(aMessage);
+    ::PostMessage(destWindow->GetWindowHandle(), internalMessage, aWParam,
+                  aLParam);
+    return;
+  }
+
+  // If the window under cursor is not in our process, it means:
+  // 1. The window may be a plugin window (GeckoPluginWindow or its descendant).
+  // 2. The window may be another application's window.
+  HWND pluginWnd = WinUtils::FindOurProcessWindow(underCursorWnd);
+  if (!pluginWnd) {
+    // If there is no plugin window in ancestors of the window under cursor,
+    // the window is for another applications (case 2).
+    // We don't need to handle this message.
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::ProcessNativeMouseWheelMessage: "
+             "Our window is not found under the cursor"));
+    return;
+  }
+
+  // If the window is a part of plugin, we should post the message to it.
+  MOZ_LOG(
+      gMouseScrollLog, LogLevel::Info,
+      ("MouseScroll::ProcessNativeMouseWheelMessage: Succeeded, "
+       "Redirecting the message to a window which is a plugin child window"));
+  ::PostMessage(underCursorWnd, aMessage, aWParam, aLParam);
+}
+
+bool MouseScrollHandler::ProcessNativeScrollMessage(nsWindow* aWidget,
+                                                    UINT aMessage,
+                                                    WPARAM aWParam,
+                                                    LPARAM aLParam) {
+  if (aLParam || mUserPrefs.IsScrollMessageHandledAsWheelMessage()) {
+    // Scroll message generated by Thinkpad Trackpoint Driver or similar
+    // Treat as a mousewheel message and scroll appropriately
+    ProcessNativeMouseWheelMessage(aWidget, aMessage, aWParam, aLParam);
+    // Always consume the scroll message if we try to emulate mouse wheel
+    // action.
+    return true;
+  }
+
+  if (SynthesizingEvent::IsSynthesizing()) {
+    mSynthesizingEvent->NativeMessageReceived(aWidget, aMessage, aWParam,
+                                              aLParam);
+  }
+
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScroll::ProcessNativeScrollMessage: aWidget=%p, "
+           "aMessage=%s, wParam=0x%08zX, lParam=0x%08" PRIXLPTR,
+           aWidget, aMessage == WM_VSCROLL ? "WM_VSCROLL" : "WM_HSCROLL",
+           aWParam, aLParam));
+
+  // Scroll message generated by external application
+  WidgetContentCommandEvent commandEvent(true, eContentCommandScroll, aWidget);
+  commandEvent.mScroll.mIsHorizontal = (aMessage == WM_HSCROLL);
+
+  switch (LOWORD(aWParam)) {
+    case SB_LINEUP:  // SB_LINELEFT
+      commandEvent.mScroll.mUnit =
+          WidgetContentCommandEvent::eCmdScrollUnit_Line;
+      commandEvent.mScroll.mAmount = -1;
+      break;
+    case SB_LINEDOWN:  // SB_LINERIGHT
+      commandEvent.mScroll.mUnit =
+          WidgetContentCommandEvent::eCmdScrollUnit_Line;
+      commandEvent.mScroll.mAmount = 1;
+      break;
+    case SB_PAGEUP:  // SB_PAGELEFT
+      commandEvent.mScroll.mUnit =
+          WidgetContentCommandEvent::eCmdScrollUnit_Page;
+      commandEvent.mScroll.mAmount = -1;
+      break;
+    case SB_PAGEDOWN:  // SB_PAGERIGHT
+      commandEvent.mScroll.mUnit =
+          WidgetContentCommandEvent::eCmdScrollUnit_Page;
+      commandEvent.mScroll.mAmount = 1;
+      break;
+    case SB_TOP:  // SB_LEFT
+      commandEvent.mScroll.mUnit =
+          WidgetContentCommandEvent::eCmdScrollUnit_Whole;
+      commandEvent.mScroll.mAmount = -1;
+      break;
+    case SB_BOTTOM:  // SB_RIGHT
+      commandEvent.mScroll.mUnit =
+          WidgetContentCommandEvent::eCmdScrollUnit_Whole;
+      commandEvent.mScroll.mAmount = 1;
+      break;
+    default:
+      return false;
+  }
+  // XXX If this is a plugin window, we should dispatch the event from
+  //     parent window.
+  aWidget->DispatchContentCommandEvent(&commandEvent);
+  return true;
+}
+
+void MouseScrollHandler::HandleMouseWheelMessage(nsWindow* aWidget,
+                                                 UINT aMessage, WPARAM aWParam,
+                                                 LPARAM aLParam) {
+  MOZ_ASSERT((aMessage == MOZ_WM_MOUSEVWHEEL || aMessage == MOZ_WM_MOUSEHWHEEL),
+             "HandleMouseWheelMessage must be called with "
+             "MOZ_WM_MOUSEVWHEEL or MOZ_WM_MOUSEHWHEEL");
+
+  MOZ_LOG(
+      gMouseScrollLog, LogLevel::Info,
+      ("MouseScroll::HandleMouseWheelMessage: aWidget=%p, "
+       "aMessage=MOZ_WM_MOUSE%sWHEEL, aWParam=0x%08zX, aLParam=0x%08" PRIXLPTR,
+       aWidget, aMessage == MOZ_WM_MOUSEVWHEEL ? "V" : "H", aWParam, aLParam));
+
+  mIsWaitingInternalMessage = false;
+
+  // If it's not allowed to cache system settings, we need to reset the cache
+  // before handling the mouse wheel message.
+  mSystemSettings.TrustedScrollSettingsDriver();
+
+  EventInfo eventInfo(aWidget, WinUtils::GetNativeMessage(aMessage), aWParam,
+                      aLParam);
+  if (!eventInfo.CanDispatchWheelEvent()) {
+    MOZ_LOG(
+        gMouseScrollLog, LogLevel::Info,
+        ("MouseScroll::HandleMouseWheelMessage: Cannot dispatch the events"));
+    mLastEventInfo.ResetTransaction();
+    return;
+  }
+
+  // Discard the remaining delta if current wheel message and last one are
+  // received by different window or to scroll different direction or
+  // different unit scroll.  Furthermore, if the last event was too old.
+  if (!mLastEventInfo.CanContinueTransaction(eventInfo)) {
+    mLastEventInfo.ResetTransaction();
+  }
+
+  mLastEventInfo.RecordEvent(eventInfo);
+
+  ModifierKeyState modKeyState = GetModifierKeyState(aMessage);
+
+  // Grab the widget, it might be destroyed by a DOM event handler.
+  RefPtr<nsWindow> kungFuDethGrip(aWidget);
+
+  WidgetWheelEvent wheelEvent(true, eWheel, aWidget);
+  if (mLastEventInfo.InitWheelEvent(aWidget, wheelEvent, modKeyState,
+                                    aLParam)) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::HandleMouseWheelMessage: dispatching "
+             "eWheel event"));
+    aWidget->DispatchWheelEvent(&wheelEvent);
+    if (aWidget->Destroyed()) {
+      MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+              ("MouseScroll::HandleMouseWheelMessage: The window was destroyed "
+               "by eWheel event"));
+      mLastEventInfo.ResetTransaction();
+      return;
+    }
+  } else {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::HandleMouseWheelMessage: eWheel event is not "
+             "dispatched"));
+  }
+}
+
+void MouseScrollHandler::HandleScrollMessageAsMouseWheelMessage(
+    nsWindow* aWidget, UINT aMessage, WPARAM aWParam, LPARAM aLParam) {
+  MOZ_ASSERT((aMessage == MOZ_WM_VSCROLL || aMessage == MOZ_WM_HSCROLL),
+             "HandleScrollMessageAsMouseWheelMessage must be called with "
+             "MOZ_WM_VSCROLL or MOZ_WM_HSCROLL");
+
+  mIsWaitingInternalMessage = false;
+
+  ModifierKeyState modKeyState = GetModifierKeyState(aMessage);
+
+  WidgetWheelEvent wheelEvent(true, eWheel, aWidget);
+  double& delta =
+      (aMessage == MOZ_WM_VSCROLL) ? wheelEvent.mDeltaY : wheelEvent.mDeltaX;
+  int32_t& lineOrPageDelta = (aMessage == MOZ_WM_VSCROLL)
+                                 ? wheelEvent.mLineOrPageDeltaY
+                                 : wheelEvent.mLineOrPageDeltaX;
+
+  delta = 1.0;
+  lineOrPageDelta = 1;
+
+  switch (LOWORD(aWParam)) {
+    case SB_PAGEUP:
+      delta = -1.0;
+      lineOrPageDelta = -1;
+      [[fallthrough]];
+    case SB_PAGEDOWN:
+      wheelEvent.mDeltaMode = dom::WheelEvent_Binding::DOM_DELTA_PAGE;
+      break;
+
+    case SB_LINEUP:
+      delta = -1.0;
+      lineOrPageDelta = -1;
+      [[fallthrough]];
+    case SB_LINEDOWN:
+      wheelEvent.mDeltaMode = dom::WheelEvent_Binding::DOM_DELTA_LINE;
+      break;
+
+    default:
+      return;
+  }
+  modKeyState.InitInputEvent(wheelEvent);
+
+  // Current mouse position may not be same as when the original message
+  // is received. However, this data is not available with the original
+  // message, which is why nullptr is passed in. We need to know the actual
+  // mouse cursor position when the original message was received.
+  InitEvent(aWidget, wheelEvent, nullptr);
+
+  MOZ_LOG(
+      gMouseScrollLog, LogLevel::Info,
+      ("MouseScroll::HandleScrollMessageAsMouseWheelMessage: aWidget=%p, "
+       "aMessage=MOZ_WM_%sSCROLL, aWParam=0x%08zX, aLParam=0x%08" PRIXLPTR ", "
+       "wheelEvent { mRefPoint: { x: %d, y: %d }, mDeltaX: %f, mDeltaY: %f, "
+       "mLineOrPageDeltaX: %d, mLineOrPageDeltaY: %d, "
+       "isShift: %s, isControl: %s, isAlt: %s, isMeta: %s }",
+       aWidget, (aMessage == MOZ_WM_VSCROLL) ? "V" : "H", aWParam, aLParam,
+       wheelEvent.mRefPoint.x.value, wheelEvent.mRefPoint.y.value,
+       wheelEvent.mDeltaX, wheelEvent.mDeltaY, wheelEvent.mLineOrPageDeltaX,
+       wheelEvent.mLineOrPageDeltaY, GetBoolName(wheelEvent.IsShift()),
+       GetBoolName(wheelEvent.IsControl()), GetBoolName(wheelEvent.IsAlt()),
+       GetBoolName(wheelEvent.IsMeta())));
+
+  aWidget->DispatchWheelEvent(&wheelEvent);
+}
+
+/******************************************************************************
+ *
+ * EventInfo
+ *
+ ******************************************************************************/
+
+MouseScrollHandler::EventInfo::EventInfo(nsWindow* aWidget, UINT aMessage,
+                                         WPARAM aWParam, LPARAM aLParam) {
+  MOZ_ASSERT(
+      aMessage == WM_MOUSEWHEEL || aMessage == WM_MOUSEHWHEEL,
+      "EventInfo must be initialized with WM_MOUSEWHEEL or WM_MOUSEHWHEEL");
+
+  MouseScrollHandler::GetInstance()->mSystemSettings.Init();
+
+  mIsVertical = (aMessage == WM_MOUSEWHEEL);
+  mIsPage =
+      MouseScrollHandler::sInstance->mSystemSettings.IsPageScroll(mIsVertical);
+  mDelta = (short)HIWORD(aWParam);
+  mWnd = aWidget->GetWindowHandle();
+  mTimeStamp = TimeStamp::Now();
+}
+
+bool MouseScrollHandler::EventInfo::CanDispatchWheelEvent() const {
+  if (!GetScrollAmount()) {
+    // XXX I think that we should dispatch mouse wheel events even if the
+    // operation will not scroll because the wheel operation really happened
+    // and web application may want to handle the event for non-scroll action.
+    return false;
+  }
+
+  return (mDelta != 0);
+}
+
+int32_t MouseScrollHandler::EventInfo::GetScrollAmount() const {
+  if (mIsPage) {
+    return 1;
+  }
+  return MouseScrollHandler::sInstance->mSystemSettings.GetScrollAmount(
+      mIsVertical);
+}
+
+/******************************************************************************
+ *
+ * LastEventInfo
+ *
+ ******************************************************************************/
+
+bool MouseScrollHandler::LastEventInfo::CanContinueTransaction(
+    const EventInfo& aNewEvent) {
+  int32_t timeout = MouseScrollHandler::sInstance->mUserPrefs
+                        .GetMouseScrollTransactionTimeout();
+  return !mWnd ||
+         (mWnd == aNewEvent.GetWindowHandle() &&
+          IsPositive() == aNewEvent.IsPositive() &&
+          mIsVertical == aNewEvent.IsVertical() &&
+          mIsPage == aNewEvent.IsPage() &&
+          (timeout < 0 || TimeStamp::Now() - mTimeStamp <=
+                              TimeDuration::FromMilliseconds(timeout)));
+}
+
+void MouseScrollHandler::LastEventInfo::ResetTransaction() {
+  if (!mWnd) {
+    return;
+  }
+
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScroll::LastEventInfo::ResetTransaction()"));
+
+  mWnd = nullptr;
+  mAccumulatedDelta = 0;
+}
+
+void MouseScrollHandler::LastEventInfo::RecordEvent(const EventInfo& aEvent) {
+  mWnd = aEvent.GetWindowHandle();
+  mDelta = aEvent.GetNativeDelta();
+  mIsVertical = aEvent.IsVertical();
+  mIsPage = aEvent.IsPage();
+  mTimeStamp = TimeStamp::Now();
+}
+
+/* static */
+int32_t MouseScrollHandler::LastEventInfo::RoundDelta(double aDelta) {
+  return (aDelta >= 0) ? (int32_t)floor(aDelta) : (int32_t)ceil(aDelta);
+}
+
+bool MouseScrollHandler::LastEventInfo::InitWheelEvent(
+    nsWindow* aWidget, WidgetWheelEvent& aWheelEvent,
+    const ModifierKeyState& aModKeyState, LPARAM aLParam) {
+  MOZ_ASSERT(aWheelEvent.mMessage == eWheel);
+
+  if (StaticPrefs::mousewheel_ignore_cursor_position_in_lparam()) {
+    InitEvent(aWidget, aWheelEvent, nullptr);
+  } else {
+    InitEvent(aWidget, aWheelEvent, &aLParam);
+  }
+
+  aModKeyState.InitInputEvent(aWheelEvent);
+
+  // Our positive delta value means to bottom or right.
+  // But positive native delta value means to top or right.
+  // Use orienter for computing our delta value with native delta value.
+  int32_t orienter = mIsVertical ? -1 : 1;
+
+  aWheelEvent.mDeltaMode = mIsPage ? dom::WheelEvent_Binding::DOM_DELTA_PAGE
+                                   : dom::WheelEvent_Binding::DOM_DELTA_LINE;
+
+  double ticks = double(mDelta) * orienter / double(WHEEL_DELTA);
+  if (mIsVertical) {
+    aWheelEvent.mWheelTicksY = ticks;
+  } else {
+    aWheelEvent.mWheelTicksX = ticks;
+  }
+
+  double& delta = mIsVertical ? aWheelEvent.mDeltaY : aWheelEvent.mDeltaX;
+  int32_t& lineOrPageDelta = mIsVertical ? aWheelEvent.mLineOrPageDeltaY
+                                         : aWheelEvent.mLineOrPageDeltaX;
+
+  double nativeDeltaPerUnit =
+      mIsPage ? double(WHEEL_DELTA) : double(WHEEL_DELTA) / GetScrollAmount();
+
+  delta = double(mDelta) * orienter / nativeDeltaPerUnit;
+  mAccumulatedDelta += mDelta;
+  lineOrPageDelta =
+      mAccumulatedDelta * orienter / RoundDelta(nativeDeltaPerUnit);
+  mAccumulatedDelta -=
+      lineOrPageDelta * orienter * RoundDelta(nativeDeltaPerUnit);
+
+  if (aWheelEvent.mDeltaMode != dom::WheelEvent_Binding::DOM_DELTA_LINE) {
+    // If the scroll delta mode isn't per line scroll, we shouldn't allow to
+    // override the system scroll speed setting.
+    aWheelEvent.mAllowToOverrideSystemScrollSpeed = false;
+  }
+
+  MOZ_LOG(
+      gMouseScrollLog, LogLevel::Info,
+      ("MouseScroll::LastEventInfo::InitWheelEvent: aWidget=%p, "
+       "aWheelEvent { mRefPoint: { x: %d, y: %d }, mDeltaX: %f, mDeltaY: %f, "
+       "mLineOrPageDeltaX: %d, mLineOrPageDeltaY: %d, "
+       "isShift: %s, isControl: %s, isAlt: %s, isMeta: %s, "
+       "mAllowToOverrideSystemScrollSpeed: %s }, "
+       "mAccumulatedDelta: %d",
+       aWidget, aWheelEvent.mRefPoint.x.value, aWheelEvent.mRefPoint.y.value,
+       aWheelEvent.mDeltaX, aWheelEvent.mDeltaY, aWheelEvent.mLineOrPageDeltaX,
+       aWheelEvent.mLineOrPageDeltaY, GetBoolName(aWheelEvent.IsShift()),
+       GetBoolName(aWheelEvent.IsControl()), GetBoolName(aWheelEvent.IsAlt()),
+       GetBoolName(aWheelEvent.IsMeta()),
+       GetBoolName(aWheelEvent.mAllowToOverrideSystemScrollSpeed),
+       mAccumulatedDelta));
+
+  return (delta != 0);
+}
+
+/******************************************************************************
+ *
+ * SystemSettings
+ *
+ ******************************************************************************/
+
+void MouseScrollHandler::SystemSettings::Init() {
+  if (mInitialized) {
+    return;
+  }
+
+  InitScrollLines();
+  InitScrollChars();
+
+  mInitialized = true;
+
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScroll::SystemSettings::Init(): initialized, "
+           "mScrollLines=%d, mScrollChars=%d",
+           mScrollLines, mScrollChars));
+}
+
+bool MouseScrollHandler::SystemSettings::InitScrollLines() {
+  int32_t oldValue = mInitialized ? mScrollLines : 0;
+  mIsReliableScrollLines = false;
+  mScrollLines = MouseScrollHandler::sInstance->mUserPrefs
+                     .GetOverriddenVerticalScrollAmout();
+  if (mScrollLines >= 0) {
+    // overridden by the pref.
+    mIsReliableScrollLines = true;
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::SystemSettings::InitScrollLines(): mScrollLines is "
+             "overridden by the pref: %d",
+             mScrollLines));
+  } else if (!::SystemParametersInfo(SPI_GETWHEELSCROLLLINES, 0, &mScrollLines,
+                                     0)) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::SystemSettings::InitScrollLines(): "
+             "::SystemParametersInfo("
+             "SPI_GETWHEELSCROLLLINES) failed"));
+    mScrollLines = DefaultScrollLines();
+  }
+
+  if (mScrollLines > WHEEL_DELTA) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::SystemSettings::InitScrollLines(): the result of "
+             "::SystemParametersInfo(SPI_GETWHEELSCROLLLINES) is too large: %d",
+             mScrollLines));
+    // sScrollLines usually equals 3 or 0 (for no scrolling)
+    // However, if sScrollLines > WHEEL_DELTA, we assume that
+    // the mouse driver wants a page scroll.  The docs state that
+    // sScrollLines should explicitly equal WHEEL_PAGESCROLL, but
+    // since some mouse drivers use an arbitrary large number instead,
+    // we have to handle that as well.
+    mScrollLines = WHEEL_PAGESCROLL;
+  }
+
+  return oldValue != mScrollLines;
+}
+
+bool MouseScrollHandler::SystemSettings::InitScrollChars() {
+  int32_t oldValue = mInitialized ? mScrollChars : 0;
+  mIsReliableScrollChars = false;
+  mScrollChars = MouseScrollHandler::sInstance->mUserPrefs
+                     .GetOverriddenHorizontalScrollAmout();
+  if (mScrollChars >= 0) {
+    // overridden by the pref.
+    mIsReliableScrollChars = true;
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::SystemSettings::InitScrollChars(): mScrollChars is "
+             "overridden by the pref: %d",
+             mScrollChars));
+  } else if (!::SystemParametersInfo(SPI_GETWHEELSCROLLCHARS, 0, &mScrollChars,
+                                     0)) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::SystemSettings::InitScrollChars(): "
+             "::SystemParametersInfo("
+             "SPI_GETWHEELSCROLLCHARS) failed, this is unexpected on Vista or "
+             "later"));
+    // XXX Should we use DefaultScrollChars()?
+    mScrollChars = 1;
+  }
+
+  if (mScrollChars > WHEEL_DELTA) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::SystemSettings::InitScrollChars(): the result of "
+             "::SystemParametersInfo(SPI_GETWHEELSCROLLCHARS) is too large: %d",
+             mScrollChars));
+    // See the comments for the case mScrollLines > WHEEL_DELTA.
+    mScrollChars = WHEEL_PAGESCROLL;
+  }
+
+  return oldValue != mScrollChars;
+}
+
+void MouseScrollHandler::SystemSettings::MarkDirty() {
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScrollHandler::SystemSettings::MarkDirty(): "
+           "Marking SystemSettings dirty"));
+  mInitialized = false;
+  // When system settings are changed, we should reset current transaction.
+  MOZ_ASSERT(sInstance,
+             "Must not be called at initializing MouseScrollHandler");
+  MouseScrollHandler::sInstance->mLastEventInfo.ResetTransaction();
+}
+
+void MouseScrollHandler::SystemSettings::RefreshCache() {
+  bool isChanged = InitScrollLines();
+  isChanged = InitScrollChars() || isChanged;
+  if (!isChanged) {
+    return;
+  }
+  // If the scroll amount is changed, we should reset current transaction.
+  MOZ_ASSERT(sInstance,
+             "Must not be called at initializing MouseScrollHandler");
+  MouseScrollHandler::sInstance->mLastEventInfo.ResetTransaction();
+}
+
+void MouseScrollHandler::SystemSettings::TrustedScrollSettingsDriver() {
+  if (!mInitialized) {
+    return;
+  }
+
+  // if the cache is initialized with prefs, we don't need to refresh it.
+  if (mIsReliableScrollLines && mIsReliableScrollChars) {
+    return;
+  }
+
+  MouseScrollHandler::UserPrefs& userPrefs =
+      MouseScrollHandler::sInstance->mUserPrefs;
+
+  // If system settings cache is disabled, we should always refresh them.
+  if (!userPrefs.IsSystemSettingCacheEnabled()) {
+    RefreshCache();
+    return;
+  }
+
+  // If pref is set to as "always trust the cache", we shouldn't refresh them
+  // in any environments.
+  if (userPrefs.IsSystemSettingCacheForciblyEnabled()) {
+    return;
+  }
+
+  // If SynTP of Synaptics or Apoint of Alps is installed, it may hook
+  // ::SystemParametersInfo() and returns different value from system settings.
+  if (Device::SynTP::IsDriverInstalled() ||
+      Device::Apoint::IsDriverInstalled()) {
+    RefreshCache();
+    return;
+  }
+
+  // XXX We're not sure about other touchpad drivers...
+}
+
+/******************************************************************************
+ *
+ * UserPrefs
+ *
+ ******************************************************************************/
+
+MouseScrollHandler::UserPrefs::UserPrefs() : mInitialized(false) {
+  // We need to reset mouse wheel transaction when all of mousewheel related
+  // prefs are changed.
+  DebugOnly<nsresult> rv =
+      Preferences::RegisterPrefixCallback(OnChange, "mousewheel.", this);
+  MOZ_ASSERT(NS_SUCCEEDED(rv), "Failed to register callback for mousewheel.");
+}
+
+MouseScrollHandler::UserPrefs::~UserPrefs() {
+  DebugOnly<nsresult> rv =
+      Preferences::UnregisterPrefixCallback(OnChange, "mousewheel.", this);
+  MOZ_ASSERT(NS_SUCCEEDED(rv), "Failed to unregister callback for mousewheel.");
+}
+
+void MouseScrollHandler::UserPrefs::Init() {
+  if (mInitialized) {
+    return;
+  }
+
+  mInitialized = true;
+
+  mScrollMessageHandledAsWheelMessage =
+      Preferences::GetBool("mousewheel.emulate_at_wm_scroll", false);
+  mEnableSystemSettingCache =
+      Preferences::GetBool("mousewheel.system_settings_cache.enabled", true);
+  mForceEnableSystemSettingCache = Preferences::GetBool(
+      "mousewheel.system_settings_cache.force_enabled", false);
+  mEmulateToMakeWindowUnderCursorForeground = Preferences::GetBool(
+      "mousewheel.debug.make_window_under_cursor_foreground", false);
+  mOverriddenVerticalScrollAmount =
+      Preferences::GetInt("mousewheel.windows.vertical_amount_override", -1);
+  mOverriddenHorizontalScrollAmount =
+      Preferences::GetInt("mousewheel.windows.horizontal_amount_override", -1);
+  mMouseScrollTransactionTimeout = Preferences::GetInt(
+      "mousewheel.windows.transaction.timeout", DEFAULT_TIMEOUT_DURATION);
+
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScroll::UserPrefs::Init(): initialized, "
+           "mScrollMessageHandledAsWheelMessage=%s, "
+           "mEnableSystemSettingCache=%s, "
+           "mForceEnableSystemSettingCache=%s, "
+           "mEmulateToMakeWindowUnderCursorForeground=%s, "
+           "mOverriddenVerticalScrollAmount=%d, "
+           "mOverriddenHorizontalScrollAmount=%d, "
+           "mMouseScrollTransactionTimeout=%d",
+           GetBoolName(mScrollMessageHandledAsWheelMessage),
+           GetBoolName(mEnableSystemSettingCache),
+           GetBoolName(mForceEnableSystemSettingCache),
+           GetBoolName(mEmulateToMakeWindowUnderCursorForeground),
+           mOverriddenVerticalScrollAmount, mOverriddenHorizontalScrollAmount,
+           mMouseScrollTransactionTimeout));
+}
+
+void MouseScrollHandler::UserPrefs::MarkDirty() {
+  MOZ_LOG(
+      gMouseScrollLog, LogLevel::Info,
+      ("MouseScrollHandler::UserPrefs::MarkDirty(): Marking UserPrefs dirty"));
+  mInitialized = false;
+  // Some prefs might override system settings, so, we should mark them dirty.
+  MouseScrollHandler::sInstance->mSystemSettings.MarkDirty();
+  // When user prefs for mousewheel are changed, we should reset current
+  // transaction.
+  MOZ_ASSERT(sInstance,
+             "Must not be called at initializing MouseScrollHandler");
+  MouseScrollHandler::sInstance->mLastEventInfo.ResetTransaction();
+}
+
+/******************************************************************************
+ *
+ * Device
+ *
+ ******************************************************************************/
+
+/* static */
+bool MouseScrollHandler::Device::GetWorkaroundPref(const char* aPrefName,
+                                                   bool aValueIfAutomatic) {
+  if (!aPrefName) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::GetWorkaroundPref(): Failed, aPrefName is "
+             "NULL"));
+    return aValueIfAutomatic;
+  }
+
+  int32_t lHackValue = 0;
+  if (NS_FAILED(Preferences::GetInt(aPrefName, &lHackValue))) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::GetWorkaroundPref(): Preferences::GetInt() "
+             "failed,"
+             " aPrefName=\"%s\", aValueIfAutomatic=%s",
+             aPrefName, GetBoolName(aValueIfAutomatic)));
+    return aValueIfAutomatic;
+  }
+
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScroll::Device::GetWorkaroundPref(): Succeeded, "
+           "aPrefName=\"%s\", aValueIfAutomatic=%s, lHackValue=%d",
+           aPrefName, GetBoolName(aValueIfAutomatic), lHackValue));
+
+  switch (lHackValue) {
+    case 0:  // disabled
+      return false;
+    case 1:  // enabled
+      return true;
+    default:  // -1: autodetect
+      return aValueIfAutomatic;
+  }
+}
+
+/* static */
+void MouseScrollHandler::Device::Init() {
+  // FYI: Thinkpad's TrackPoint is Apoint of Alps and UltraNav is SynTP of
+  //      Synaptics.  So, those drivers' information should be initialized
+  //      before calling methods of TrackPoint and UltraNav.
+  SynTP::Init();
+  Elantech::Init();
+  Apoint::Init();
+
+  sFakeScrollableWindowNeeded = GetWorkaroundPref(
+      "ui.trackpoint_hack.enabled", (TrackPoint::IsDriverInstalled() ||
+                                     UltraNav::IsObsoleteDriverInstalled()));
+
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScroll::Device::Init(): sFakeScrollableWindowNeeded=%s",
+           GetBoolName(sFakeScrollableWindowNeeded)));
+}
+
+/******************************************************************************
+ *
+ * Device::SynTP
+ *
+ ******************************************************************************/
+
+/* static */
+void MouseScrollHandler::Device::SynTP::Init() {
+  if (sInitialized) {
+    return;
+  }
+
+  sInitialized = true;
+  sMajorVersion = 0;
+  sMinorVersion = -1;
+
+  wchar_t buf[40];
+  if (!WinRegistry::GetString(
+          HKEY_LOCAL_MACHINE, u"Software\\Synaptics\\SynTP\\Install"_ns,
+          u"DriverVersion"_ns, buf, WinRegistry::kLegacyWinUtilsStringFlags)) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::SynTP::Init(): "
+             "SynTP driver is not found"));
+    return;
+  }
+
+  sMajorVersion = wcstol(buf, nullptr, 10);
+  sMinorVersion = 0;
+  wchar_t* p = wcschr(buf, L'.');
+  if (p) {
+    sMinorVersion = wcstol(p + 1, nullptr, 10);
+  }
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScroll::Device::SynTP::Init(): "
+           "found driver version = %d.%d",
+           sMajorVersion, sMinorVersion));
+}
+
+/******************************************************************************
+ *
+ * Device::Elantech
+ *
+ ******************************************************************************/
+
+/* static */
+void MouseScrollHandler::Device::Elantech::Init() {
+  int32_t version = GetDriverMajorVersion();
+  bool needsHack = Device::GetWorkaroundPref(
+      "ui.elantech_gesture_hacks.enabled", version != 0);
+  sUseSwipeHack = needsHack && version <= 7;
+  sUsePinchHack = needsHack && version <= 8;
+
+  MOZ_LOG(
+      gMouseScrollLog, LogLevel::Info,
+      ("MouseScroll::Device::Elantech::Init(): version=%d, sUseSwipeHack=%s, "
+       "sUsePinchHack=%s",
+       version, GetBoolName(sUseSwipeHack), GetBoolName(sUsePinchHack)));
+}
+
+/* static */
+int32_t MouseScrollHandler::Device::Elantech::GetDriverMajorVersion() {
+  wchar_t buf[40];
+  // The driver version is found in one of these two registry keys.
+  if (!WinRegistry::GetString(
+          HKEY_CURRENT_USER, u"Software\\Elantech\\MainOption"_ns,
+          u"DriverVersion"_ns, buf, WinRegistry::kLegacyWinUtilsStringFlags) &&
+      !WinRegistry::GetString(HKEY_CURRENT_USER, u"Software\\Elantech"_ns,
+                              u"DriverVersion"_ns, buf,
+                              WinRegistry::kLegacyWinUtilsStringFlags)) {
+    return 0;
+  }
+
+  // Assume that the major version number can be found just after a space
+  // or at the start of the string.
+  for (wchar_t* p = buf; *p; p++) {
+    if (*p >= L'0' && *p <= L'9' && (p == buf || *(p - 1) == L' ')) {
+      return wcstol(p, nullptr, 10);
+    }
+  }
+
+  return 0;
+}
+
+/* static */
+bool MouseScrollHandler::Device::Elantech::IsHelperWindow(HWND aWnd) {
+  // The helper window cannot be distinguished based on its window class, so we
+  // need to check if it is owned by the helper process, ETDCtrl.exe.
+
+  const wchar_t* filenameSuffix = L"\\etdctrl.exe";
+  const int filenameSuffixLength = 12;
+
+  DWORD pid;
+  ::GetWindowThreadProcessId(aWnd, &pid);
+
+  HANDLE hProcess = ::OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid);
+  if (!hProcess) {
+    return false;
+  }
+
+  bool result = false;
+  wchar_t path[256] = {L'\0'};
+  if (::GetProcessImageFileNameW(hProcess, path, ArrayLength(path))) {
+    int pathLength = lstrlenW(path);
+    if (pathLength >= filenameSuffixLength) {
+      if (lstrcmpiW(path + pathLength - filenameSuffixLength, filenameSuffix) ==
+          0) {
+        result = true;
+      }
+    }
+  }
+  ::CloseHandle(hProcess);
+
+  return result;
+}
+
+/* static */
+bool MouseScrollHandler::Device::Elantech::HandleKeyMessage(nsWindow* aWidget,
+                                                            UINT aMsg,
+                                                            WPARAM aWParam,
+                                                            LPARAM aLParam) {
+  // The Elantech touchpad driver understands three-finger swipe left and
+  // right gestures, and translates them into Page Up and Page Down key
+  // events for most applications.  For Firefox 3.6, it instead sends
+  // Alt+Left and Alt+Right to trigger browser back/forward actions.  As
+  // with the Thinkpad Driver hack in nsWindow::Create, the change in
+  // HWND structure makes Firefox not trigger the driver's heuristics
+  // any longer.
+  //
+  // The Elantech driver actually sends these messages for a three-finger
+  // swipe right:
+  //
+  //   WM_KEYDOWN virtual_key = 0xCC or 0xFF ScanCode = 00
+  //   WM_KEYDOWN virtual_key = VK_NEXT      ScanCode = 00
+  //   WM_KEYUP   virtual_key = VK_NEXT      ScanCode = 00
+  //   WM_KEYUP   virtual_key = 0xCC or 0xFF ScanCode = 00
+  //
+  // Whether 0xCC or 0xFF is sent is suspected to depend on the driver
+  // version.  7.0.4.12_14Jul09_WHQL, 7.0.5.10, and 7.0.6.0 generate 0xCC.
+  // 7.0.4.3 from Asus on EeePC generates 0xFF.
+  //
+  // On some hardware, IS_VK_DOWN(0xFF) returns true even when Elantech
+  // messages are not involved, meaning that alone is not enough to
+  // distinguish the gesture from a regular Page Up or Page Down key press.
+  // The ScanCode is therefore also tested to detect the gesture.
+  // We then pretend that we should dispatch "Go Forward" command.  Similarly
+  // for VK_PRIOR and "Go Back" command.
+  if (sUseSwipeHack && (aWParam == VK_NEXT || aWParam == VK_PRIOR) &&
+      WinUtils::GetScanCode(aLParam) == 0 &&
+      (IS_VK_DOWN(0xFF) || IS_VK_DOWN(0xCC))) {
+    if (aMsg == WM_KEYDOWN) {
+      MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+              ("MouseScroll::Device::Elantech::HandleKeyMessage(): Dispatching "
+               "%s command event",
+               aWParam == VK_NEXT ? "Forward" : "Back"));
+
+      WidgetCommandEvent appCommandEvent(
+          true, (aWParam == VK_NEXT) ? nsGkAtoms::Forward : nsGkAtoms::Back,
+          aWidget);
+
+      // In this scenario, the coordinate of the event isn't supplied, so pass
+      // nullptr as an argument to indicate using the coordinate from the last
+      // available window message.
+      InitEvent(aWidget, appCommandEvent, nullptr);
+      aWidget->DispatchWindowEvent(appCommandEvent);
+    } else {
+      MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+              ("MouseScroll::Device::Elantech::HandleKeyMessage(): Consumed"));
+    }
+    return true;  // consume the message (doesn't need to dispatch key events)
+  }
+
+  // Version 8 of the Elantech touchpad driver sends these messages for
+  // zoom gestures:
+  //
+  //   WM_KEYDOWN    virtual_key = 0xCC        time = 10
+  //   WM_KEYDOWN    virtual_key = VK_CONTROL  time = 10
+  //   WM_MOUSEWHEEL                           time = ::GetTickCount()
+  //   WM_KEYUP      virtual_key = VK_CONTROL  time = 10
+  //   WM_KEYUP      virtual_key = 0xCC        time = 10
+  //
+  // The result of this is that we process all of the WM_KEYDOWN/WM_KEYUP
+  // messages first because their timestamps make them appear to have
+  // been sent before the WM_MOUSEWHEEL message.  To work around this,
+  // we store the current time when we process the WM_KEYUP message and
+  // assume that any WM_MOUSEWHEEL message with a timestamp before that
+  // time is one that should be processed as if the Control key was down.
+  if (sUsePinchHack && aMsg == WM_KEYUP && aWParam == VK_CONTROL &&
+      ::GetMessageTime() == 10) {
+    // We look only at the bottom 31 bits of the system tick count since
+    // GetMessageTime returns a LONG, which is signed, so we want values
+    // that are more easily comparable.
+    sZoomUntil = ::GetTickCount() & 0x7FFFFFFF;
+
+    MOZ_LOG(
+        gMouseScrollLog, LogLevel::Info,
+        ("MouseScroll::Device::Elantech::HandleKeyMessage(): sZoomUntil=%lu",
+         sZoomUntil));
+  }
+
+  return false;
+}
+
+/* static */
+void MouseScrollHandler::Device::Elantech::UpdateZoomUntil() {
+  if (!sZoomUntil) {
+    return;
+  }
+
+  // For the Elantech Touchpad Zoom Gesture Hack, we should check that the
+  // system time (32-bit milliseconds) hasn't wrapped around.  Otherwise we
+  // might get into the situation where wheel events for the next 50 days of
+  // system uptime are assumed to be Ctrl+Wheel events.  (It is unlikely that
+  // we would get into that state, because the system would already need to be
+  // up for 50 days and the Control key message would need to be processed just
+  // before the system time overflow and the wheel message just after.)
+  //
+  // We also take the chance to reset sZoomUntil if we simply have passed that
+  // time.
+  LONG msgTime = ::GetMessageTime();
+  if ((sZoomUntil >= 0x3fffffffu && DWORD(msgTime) < 0x40000000u) ||
+      (sZoomUntil < DWORD(msgTime))) {
+    sZoomUntil = 0;
+
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::Elantech::UpdateZoomUntil(): "
+             "sZoomUntil was reset"));
+  }
+}
+
+/* static */
+bool MouseScrollHandler::Device::Elantech::IsZooming() {
+  // Assume the Control key is down if the Elantech touchpad has sent the
+  // mis-ordered WM_KEYDOWN/WM_MOUSEWHEEL messages.  (See the comment in
+  // OnKeyUp.)
+  return (sZoomUntil && static_cast<DWORD>(::GetMessageTime()) < sZoomUntil);
+}
+
+/******************************************************************************
+ *
+ * Device::Apoint
+ *
+ ******************************************************************************/
+
+/* static */
+void MouseScrollHandler::Device::Apoint::Init() {
+  if (sInitialized) {
+    return;
+  }
+
+  sInitialized = true;
+  sMajorVersion = 0;
+  sMinorVersion = -1;
+
+  wchar_t buf[40];
+  if (!WinRegistry::GetString(HKEY_LOCAL_MACHINE, u"Software\\Alps\\Apoint"_ns,
+                              u"ProductVer"_ns, buf,
+                              WinRegistry::kLegacyWinUtilsStringFlags)) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::Apoint::Init(): "
+             "Apoint driver is not found"));
+    return;
+  }
+
+  sMajorVersion = wcstol(buf, nullptr, 10);
+  sMinorVersion = 0;
+  wchar_t* p = wcschr(buf, L'.');
+  if (p) {
+    sMinorVersion = wcstol(p + 1, nullptr, 10);
+  }
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScroll::Device::Apoint::Init(): "
+           "found driver version = %d.%d",
+           sMajorVersion, sMinorVersion));
+}
+
+/******************************************************************************
+ *
+ * Device::TrackPoint
+ *
+ ******************************************************************************/
+
+/* static */
+bool MouseScrollHandler::Device::TrackPoint::IsDriverInstalled() {
+  if (WinRegistry::HasKey(HKEY_CURRENT_USER,
+                          u"Software\\Lenovo\\TrackPoint"_ns)) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::TrackPoint::IsDriverInstalled(): "
+             "Lenovo's TrackPoint driver is found"));
+    return true;
+  }
+
+  if (WinRegistry::HasKey(HKEY_CURRENT_USER,
+                          u"Software\\Alps\\Apoint\\TrackPoint"_ns)) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::TrackPoint::IsDriverInstalled(): "
+             "Alps's TrackPoint driver is found"));
+    return true;
+  }
+
+  return false;
+}
+
+/******************************************************************************
+ *
+ * Device::UltraNav
+ *
+ ******************************************************************************/
+
+/* static */
+bool MouseScrollHandler::Device::UltraNav::IsObsoleteDriverInstalled() {
+  if (WinRegistry::HasKey(HKEY_CURRENT_USER,
+                          u"Software\\Lenovo\\UltraNav"_ns)) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::UltraNav::IsObsoleteDriverInstalled(): "
+             "Lenovo's UltraNav driver is found"));
+    return true;
+  }
+
+  bool installed = false;
+  if (WinRegistry::HasKey(HKEY_CURRENT_USER,
+                          u"Software\\Synaptics\\SynTPEnh\\UltraNavUSB"_ns)) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::UltraNav::IsObsoleteDriverInstalled(): "
+             "Synaptics's UltraNav (USB) driver is found"));
+    installed = true;
+  } else if (WinRegistry::HasKey(
+                 HKEY_CURRENT_USER,
+                 u"Software\\Synaptics\\SynTPEnh\\UltraNavPS2"_ns)) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::UltraNav::IsObsoleteDriverInstalled(): "
+             "Synaptics's UltraNav (PS/2) driver is found"));
+    installed = true;
+  }
+
+  if (!installed) {
+    return false;
+  }
+
+  int32_t majorVersion = Device::SynTP::GetDriverMajorVersion();
+  if (!majorVersion) {
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::UltraNav::IsObsoleteDriverInstalled(): "
+             "Failed to get UltraNav driver version"));
+    return false;
+  }
+  int32_t minorVersion = Device::SynTP::GetDriverMinorVersion();
+  return majorVersion < 15 || (majorVersion == 15 && minorVersion == 0);
+}
+
+/******************************************************************************
+ *
+ * Device::SetPoint
+ *
+ ******************************************************************************/
+
+/* static */
+bool MouseScrollHandler::Device::SetPoint::IsGetMessagePosResponseValid(
+    UINT aMessage, WPARAM aWParam, LPARAM aLParam) {
+  if (aMessage != WM_MOUSEHWHEEL) {
+    return false;
+  }
+
+  POINTS pts = MouseScrollHandler::GetCurrentMessagePos();
+  LPARAM messagePos = MAKELPARAM(pts.x, pts.y);
+
+  // XXX We should check whether SetPoint is installed or not by registry.
+
+  // SetPoint, Logitech (Logicool) mouse driver, (confirmed with 4.82.11 and
+  // MX-1100) always sets 0 to the lParam of WM_MOUSEHWHEEL.  The driver SENDs
+  // one message at first time, this time, ::GetMessagePos() works fine.
+  // Then, we will return 0 (0 means we process it) to the message. Then, the
+  // driver will POST the same messages continuously during the wheel tilted.
+  // But ::GetMessagePos() API always returns (0, 0) for them, even if the
+  // actual mouse cursor isn't 0,0.  Therefore, we cannot trust the result of
+  // ::GetMessagePos API if the sender is SetPoint.
+  if (!sMightBeUsing && !aLParam && aLParam != messagePos &&
+      ::InSendMessage()) {
+    sMightBeUsing = true;
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::SetPoint::IsGetMessagePosResponseValid(): "
+             "Might using SetPoint"));
+  } else if (sMightBeUsing && aLParam != 0 && ::InSendMessage()) {
+    // The user has changed the mouse from Logitech's to another one (e.g.,
+    // the user has changed to the touchpad of the notebook.
+    sMightBeUsing = false;
+    MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+            ("MouseScroll::Device::SetPoint::IsGetMessagePosResponseValid(): "
+             "Might stop using SetPoint"));
+  }
+  return (sMightBeUsing && !aLParam && !messagePos);
+}
+
+/******************************************************************************
+ *
+ * SynthesizingEvent
+ *
+ ******************************************************************************/
+
+/* static */
+bool MouseScrollHandler::SynthesizingEvent::IsSynthesizing() {
+  return MouseScrollHandler::sInstance &&
+         MouseScrollHandler::sInstance->mSynthesizingEvent &&
+         MouseScrollHandler::sInstance->mSynthesizingEvent->mStatus !=
+             NOT_SYNTHESIZING;
+}
+
+nsresult MouseScrollHandler::SynthesizingEvent::Synthesize(
+    const POINTS& aCursorPoint, HWND aWnd, UINT aMessage, WPARAM aWParam,
+    LPARAM aLParam, const BYTE (&aKeyStates)[256]) {
+  MOZ_LOG(
+      gMouseScrollLog, LogLevel::Info,
+      ("MouseScrollHandler::SynthesizingEvent::Synthesize(): aCursorPoint: { "
+       "x: %d, y: %d }, aWnd=0x%p, aMessage=0x%04X, aWParam=0x%08zX, "
+       "aLParam=0x%08" PRIXLPTR ", IsSynthesized()=%s, mStatus=%s",
+       aCursorPoint.x, aCursorPoint.y, aWnd, aMessage, aWParam, aLParam,
+       GetBoolName(IsSynthesizing()), GetStatusName()));
+
+  if (IsSynthesizing()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  ::GetKeyboardState(mOriginalKeyState);
+
+  // Note that we cannot use ::SetCursorPos() because it works asynchronously.
+  // We should SEND the message for reducing the possibility of receiving
+  // unexpected message which were not sent from here.
+  mCursorPoint = aCursorPoint;
+
+  mWnd = aWnd;
+  mMessage = aMessage;
+  mWParam = aWParam;
+  mLParam = aLParam;
+
+  memcpy(mKeyState, aKeyStates, sizeof(mKeyState));
+  ::SetKeyboardState(mKeyState);
+
+  mStatus = SENDING_MESSAGE;
+
+  // Don't assume that aWnd is always managed by nsWindow.  It might be
+  // a plugin window.
+  ::SendMessage(aWnd, aMessage, aWParam, aLParam);
+
+  return NS_OK;
+}
+
+void MouseScrollHandler::SynthesizingEvent::NativeMessageReceived(
+    nsWindow* aWidget, UINT aMessage, WPARAM aWParam, LPARAM aLParam) {
+  if (mStatus == SENDING_MESSAGE && mMessage == aMessage &&
+      mWParam == aWParam && mLParam == aLParam) {
+    mStatus = NATIVE_MESSAGE_RECEIVED;
+    if (aWidget && aWidget->GetWindowHandle() == mWnd) {
+      return;
+    }
+    // Otherwise, the message may not be sent by us.
+  }
+
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScrollHandler::SynthesizingEvent::NativeMessageReceived(): "
+           "aWidget=%p, aWidget->GetWindowHandle()=0x%p, mWnd=0x%p, "
+           "aMessage=0x%04X, aWParam=0x%08zX, aLParam=0x%08" PRIXLPTR
+           ", mStatus=%s",
+           aWidget, aWidget ? aWidget->GetWindowHandle() : nullptr, mWnd,
+           aMessage, aWParam, aLParam, GetStatusName()));
+
+  // We failed to receive our sent message, we failed to do the job.
+  Finish();
+
+  return;
+}
+
+void MouseScrollHandler::SynthesizingEvent::
+    NotifyNativeMessageHandlingFinished() {
+  if (!IsSynthesizing()) {
+    return;
+  }
+
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScrollHandler::SynthesizingEvent::"
+           "NotifyNativeMessageHandlingFinished(): IsWaitingInternalMessage=%s",
+           GetBoolName(MouseScrollHandler::IsWaitingInternalMessage())));
+
+  if (MouseScrollHandler::IsWaitingInternalMessage()) {
+    mStatus = INTERNAL_MESSAGE_POSTED;
+    return;
+  }
+
+  // If the native message handler didn't post our internal message,
+  // we our job is finished.
+  // TODO: When we post the message to plugin window, there is remaning job.
+  Finish();
+}
+
+void MouseScrollHandler::SynthesizingEvent::
+    NotifyInternalMessageHandlingFinished() {
+  if (!IsSynthesizing()) {
+    return;
+  }
+
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScrollHandler::SynthesizingEvent::"
+           "NotifyInternalMessageHandlingFinished()"));
+
+  Finish();
+}
+
+void MouseScrollHandler::SynthesizingEvent::Finish() {
+  if (!IsSynthesizing()) {
+    return;
+  }
+
+  MOZ_LOG(gMouseScrollLog, LogLevel::Info,
+          ("MouseScrollHandler::SynthesizingEvent::Finish()"));
+
+  // Restore the original key state.
+  ::SetKeyboardState(mOriginalKeyState);
+
+  mStatus = NOT_SYNTHESIZING;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/WinMouseScrollHandler.h b/widget/windows/WinMouseScrollHandler.h
new file mode 100644
index 0000000000..ecf6c3df44
--- /dev/null
+++ b/widget/windows/WinMouseScrollHandler.h
@@ -0,0 +1,567 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_WinMouseScrollHandler_h__
+#define mozilla_widget_WinMouseScrollHandler_h__
+
+#include "nscore.h"
+#include "nsDebug.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/TimeStamp.h"
+#include "Units.h"
+#include <windows.h>
+#include "nsPoint.h"
+
+class nsWindow;
+
+namespace mozilla {
+namespace widget {
+
+class ModifierKeyState;
+
+struct MSGResult;
+
+class MouseScrollHandler {
+ public:
+  static MouseScrollHandler* GetInstance();
+
+  static void Initialize();
+  static void Shutdown();
+
+  static bool NeedsMessage(UINT aMsg);
+  static bool ProcessMessage(nsWindow* aWidget, UINT msg, WPARAM wParam,
+                             LPARAM lParam, MSGResult& aResult);
+
+  /**
+   * See nsIWidget::SynthesizeNativeMouseScrollEvent() for the detail about
+   * this method.
+   */
+  static nsresult SynthesizeNativeMouseScrollEvent(
+      nsWindow* aWidget, const LayoutDeviceIntPoint& aPoint,
+      uint32_t aNativeMessage, int32_t aDelta, uint32_t aModifierFlags,
+      uint32_t aAdditionalFlags);
+
+  /**
+   * IsWaitingInternalMessage() returns true if MouseScrollHandler posted
+   * an internal message for a native mouse wheel message and has not
+   * received it. Otherwise, false.
+   */
+  static bool IsWaitingInternalMessage() {
+    return sInstance && sInstance->mIsWaitingInternalMessage;
+  }
+
+ private:
+  MouseScrollHandler();
+  ~MouseScrollHandler();
+
+  bool mIsWaitingInternalMessage;
+
+  static void MaybeLogKeyState();
+
+  static MouseScrollHandler* sInstance;
+
+  /**
+   * InitEvent() initializes the aEvent.  If aPoint is null, the result of
+   * GetCurrentMessagePos() will be used.
+   */
+  static void InitEvent(nsWindow* aWidget, WidgetGUIEvent& aEvent,
+                        LPARAM* aPoint);
+
+  /**
+   * GetModifierKeyState() returns current modifier key state.
+   * Note that some devices need some hack for the modifier key state.
+   * This method does it automatically.
+   *
+   * @param aMessage    Handling message.
+   */
+  static ModifierKeyState GetModifierKeyState(UINT aMessage);
+
+  /**
+   * MozGetMessagePos() returns the mouse cursor position when GetMessage()
+   * was called last time.  However, if we're sending a native message,
+   * this returns the specified cursor position by
+   * SynthesizeNativeMouseScrollEvent().
+   */
+  static POINTS GetCurrentMessagePos();
+
+  /**
+   * ProcessNativeMouseWheelMessage() processes WM_MOUSEWHEEL and
+   * WM_MOUSEHWHEEL.  Additionally, processes WM_VSCROLL and WM_HSCROLL if they
+   * should be processed as mouse wheel message.
+   * This method posts MOZ_WM_MOUSEVWHEEL, MOZ_WM_MOUSEHWHEEL,
+   * MOZ_WM_VSCROLL or MOZ_WM_HSCROLL if we need to dispatch mouse scroll
+   * events.  That avoids deadlock with plugin process.
+   *
+   * @param aWidget     A window which receives the message.
+   * @param aMessage    WM_MOUSEWHEEL, WM_MOUSEHWHEEL, WM_VSCROLL or
+   *                    WM_HSCROLL.
+   * @param aWParam     The wParam value of the message.
+   * @param aLParam     The lParam value of the message.
+   */
+  void ProcessNativeMouseWheelMessage(nsWindow* aWidget, UINT aMessage,
+                                      WPARAM aWParam, LPARAM aLParam);
+
+  /**
+   * ProcessNativeScrollMessage() processes WM_VSCROLL and WM_HSCROLL.
+   * This method just call ProcessMouseWheelMessage() if the message should be
+   * processed as mouse wheel message.  Otherwise, dispatches a content
+   * command event.
+   *
+   * @param aWidget     A window which receives the message.
+   * @param aMessage    WM_VSCROLL or WM_HSCROLL.
+   * @param aWParam     The wParam value of the message.
+   * @param aLParam     The lParam value of the message.
+   * @return            TRUE if the message is processed.  Otherwise, FALSE.
+   */
+  bool ProcessNativeScrollMessage(nsWindow* aWidget, UINT aMessage,
+                                  WPARAM aWParam, LPARAM aLParam);
+
+  /**
+   * HandleMouseWheelMessage() processes MOZ_WM_MOUSEVWHEEL and
+   * MOZ_WM_MOUSEHWHEEL which are posted when one of our windows received
+   * WM_MOUSEWHEEL or WM_MOUSEHWHEEL for avoiding deadlock with OOPP.
+   *
+   * @param aWidget     A window which receives the wheel message.
+   * @param aMessage    MOZ_WM_MOUSEWHEEL or MOZ_WM_MOUSEHWHEEL.
+   * @param aWParam     The wParam value of the original message.
+   * @param aLParam     The lParam value of the original message.
+   */
+  void HandleMouseWheelMessage(nsWindow* aWidget, UINT aMessage, WPARAM aWParam,
+                               LPARAM aLParam);
+
+  /**
+   * HandleScrollMessageAsMouseWheelMessage() processes the MOZ_WM_VSCROLL and
+   * MOZ_WM_HSCROLL which are posted when one of mouse windows received
+   * WM_VSCROLL or WM_HSCROLL and user wants them to emulate mouse wheel
+   * message's behavior.
+   *
+   * @param aWidget     A window which receives the scroll message.
+   * @param aMessage    MOZ_WM_VSCROLL or MOZ_WM_HSCROLL.
+   * @param aWParam     The wParam value of the original message.
+   * @param aLParam     The lParam value of the original message.
+   */
+  void HandleScrollMessageAsMouseWheelMessage(nsWindow* aWidget, UINT aMessage,
+                                              WPARAM aWParam, LPARAM aLParam);
+
+  /**
+   * ComputeMessagePos() computes the cursor position when the message was
+   * added to the queue.
+   *
+   * @param aMessage    Handling message.
+   * @param aWParam     Handling message's wParam.
+   * @param aLParam     Handling message's lParam.
+   * @return            Mouse cursor position when the message is added to
+   *                    the queue or current cursor position if the result of
+   *                    ::GetMessagePos() is broken.
+   */
+  POINT ComputeMessagePos(UINT aMessage, WPARAM aWParam, LPARAM aLParam);
+
+  class EventInfo {
+   public:
+    /**
+     * @param aWidget   An nsWindow which is handling the event.
+     * @param aMessage  Must be WM_MOUSEWHEEL or WM_MOUSEHWHEEL.
+     */
+    EventInfo(nsWindow* aWidget, UINT aMessage, WPARAM aWParam, LPARAM aLParam);
+
+    bool CanDispatchWheelEvent() const;
+
+    int32_t GetNativeDelta() const { return mDelta; }
+    HWND GetWindowHandle() const { return mWnd; }
+    const TimeStamp& GetTimeStamp() const { return mTimeStamp; }
+    bool IsVertical() const { return mIsVertical; }
+    bool IsPositive() const { return (mDelta > 0); }
+    bool IsPage() const { return mIsPage; }
+
+    /**
+     * @return          Number of lines or pages scrolled per WHEEL_DELTA.
+     */
+    int32_t GetScrollAmount() const;
+
+   protected:
+    EventInfo()
+        : mIsVertical(false), mIsPage(false), mDelta(0), mWnd(nullptr) {}
+
+    // TRUE if event is for vertical scroll.  Otherwise, FALSE.
+    bool mIsVertical;
+    // TRUE if event scrolls per page, otherwise, FALSE.
+    bool mIsPage;
+    // The native delta value.
+    int32_t mDelta;
+    // The window handle which is handling the event.
+    HWND mWnd;
+    // Timestamp of the event.
+    TimeStamp mTimeStamp;
+  };
+
+  class LastEventInfo : public EventInfo {
+   public:
+    LastEventInfo() : EventInfo(), mAccumulatedDelta(0) {}
+
+    /**
+     * CanContinueTransaction() checks whether the new event can continue the
+     * last transaction or not.  Note that if there is no transaction, this
+     * returns true.
+     */
+    bool CanContinueTransaction(const EventInfo& aNewEvent);
+
+    /**
+     * ResetTransaction() resets the transaction, i.e., the instance forgets
+     * the last event information.
+     */
+    void ResetTransaction();
+
+    /**
+     * RecordEvent() saves the information of new event.
+     */
+    void RecordEvent(const EventInfo& aEvent);
+
+    /**
+     * InitWheelEvent() initializes NS_WHEEL_WHEEL event and
+     * recomputes the remaning detla for the event.
+     * This must be called only once during handling a message and after
+     * RecordEvent() is called.
+     *
+     * @param aWidget           A window which will dispatch the event.
+     * @param aWheelEvent       An NS_WHEEL_WHEEL event, this will be
+     *                          initialized.
+     * @param aModKeyState      Current modifier key state.
+     * @return                  TRUE if the event is ready to dispatch.
+     *                          Otherwise, FALSE.
+     */
+    bool InitWheelEvent(nsWindow* aWidget, WidgetWheelEvent& aWheelEvent,
+                        const ModifierKeyState& aModKeyState, LPARAM aLParam);
+
+   private:
+    static int32_t RoundDelta(double aDelta);
+
+    int32_t mAccumulatedDelta;
+  };
+
+  LastEventInfo mLastEventInfo;
+
+  class SystemSettings {
+   public:
+    SystemSettings() : mInitialized(false) {}
+
+    void Init();
+    void MarkDirty();
+    void NotifyUserPrefsMayOverrideSystemSettings();
+
+    // On some environments, SystemParametersInfo() may be hooked by touchpad
+    // utility or something.  In such case, when user changes active pointing
+    // device to another one, the result of SystemParametersInfo() may be
+    // changed without WM_SETTINGCHANGE message.  For avoiding this trouble,
+    // we need to modify cache of system settings at every wheel message
+    // handling if we meet known device whose utility may hook the API.
+    void TrustedScrollSettingsDriver();
+
+    int32_t GetScrollAmount(bool aForVertical) const {
+      MOZ_ASSERT(mInitialized, "SystemSettings must be initialized");
+      return aForVertical ? mScrollLines : mScrollChars;
+    }
+
+    bool IsPageScroll(bool aForVertical) const {
+      MOZ_ASSERT(mInitialized, "SystemSettings must be initialized");
+      return aForVertical ? (uint32_t(mScrollLines) == WHEEL_PAGESCROLL)
+                          : (uint32_t(mScrollChars) == WHEEL_PAGESCROLL);
+    }
+
+    // The default vertical and horizontal scrolling speed is 3, this is defined
+    // on the document of SystemParametersInfo in MSDN.
+    static int32_t DefaultScrollLines() { return 3; }
+
+   private:
+    bool mInitialized;
+    // The result of SystemParametersInfo() may not be reliable since it may
+    // be hooked.  So, if the values are initialized with prefs, we can trust
+    // the value.  Following mIsReliableScroll* are set true when mScroll* are
+    // initialized with prefs.
+    bool mIsReliableScrollLines;
+    bool mIsReliableScrollChars;
+
+    int32_t mScrollLines;
+    int32_t mScrollChars;
+
+    // Returns true if cached value is changed.
+    bool InitScrollLines();
+    bool InitScrollChars();
+
+    void RefreshCache();
+  };
+
+  SystemSettings mSystemSettings;
+
+  class UserPrefs {
+   public:
+    UserPrefs();
+    ~UserPrefs();
+
+    void MarkDirty();
+
+    bool IsScrollMessageHandledAsWheelMessage() {
+      Init();
+      return mScrollMessageHandledAsWheelMessage;
+    }
+
+    bool IsSystemSettingCacheEnabled() {
+      Init();
+      return mEnableSystemSettingCache;
+    }
+
+    bool IsSystemSettingCacheForciblyEnabled() {
+      Init();
+      return mForceEnableSystemSettingCache;
+    }
+
+    bool ShouldEmulateToMakeWindowUnderCursorForeground() {
+      Init();
+      return mEmulateToMakeWindowUnderCursorForeground;
+    }
+
+    int32_t GetOverriddenVerticalScrollAmout() {
+      Init();
+      return mOverriddenVerticalScrollAmount;
+    }
+
+    int32_t GetOverriddenHorizontalScrollAmout() {
+      Init();
+      return mOverriddenHorizontalScrollAmount;
+    }
+
+    int32_t GetMouseScrollTransactionTimeout() {
+      Init();
+      return mMouseScrollTransactionTimeout;
+    }
+
+   private:
+    void Init();
+
+    static void OnChange(const char* aPrefName, void* aSelf) {
+      static_cast<UserPrefs*>(aSelf)->MarkDirty();
+    }
+
+    bool mInitialized;
+    bool mScrollMessageHandledAsWheelMessage;
+    bool mEnableSystemSettingCache;
+    bool mForceEnableSystemSettingCache;
+    bool mEmulateToMakeWindowUnderCursorForeground;
+    int32_t mOverriddenVerticalScrollAmount;
+    int32_t mOverriddenHorizontalScrollAmount;
+    int32_t mMouseScrollTransactionTimeout;
+  };
+
+  UserPrefs mUserPrefs;
+
+  class SynthesizingEvent {
+   public:
+    SynthesizingEvent()
+        : mWnd(nullptr),
+          mMessage(0),
+          mWParam(0),
+          mLParam(0),
+          mStatus(NOT_SYNTHESIZING) {}
+
+    ~SynthesizingEvent() {}
+
+    static bool IsSynthesizing();
+
+    nsresult Synthesize(const POINTS& aCursorPoint, HWND aWnd, UINT aMessage,
+                        WPARAM aWParam, LPARAM aLParam,
+                        const BYTE (&aKeyStates)[256]);
+
+    void NativeMessageReceived(nsWindow* aWidget, UINT aMessage, WPARAM aWParam,
+                               LPARAM aLParam);
+
+    void NotifyNativeMessageHandlingFinished();
+    void NotifyInternalMessageHandlingFinished();
+
+    const POINTS& GetCursorPoint() const { return mCursorPoint; }
+
+   private:
+    POINTS mCursorPoint;
+    HWND mWnd;
+    UINT mMessage;
+    WPARAM mWParam;
+    LPARAM mLParam;
+    BYTE mKeyState[256];
+    BYTE mOriginalKeyState[256];
+
+    enum Status {
+      NOT_SYNTHESIZING,
+      SENDING_MESSAGE,
+      NATIVE_MESSAGE_RECEIVED,
+      INTERNAL_MESSAGE_POSTED,
+    };
+    Status mStatus;
+
+    const char* GetStatusName() {
+      switch (mStatus) {
+        case NOT_SYNTHESIZING:
+          return "NOT_SYNTHESIZING";
+        case SENDING_MESSAGE:
+          return "SENDING_MESSAGE";
+        case NATIVE_MESSAGE_RECEIVED:
+          return "NATIVE_MESSAGE_RECEIVED";
+        case INTERNAL_MESSAGE_POSTED:
+          return "INTERNAL_MESSAGE_POSTED";
+        default:
+          return "Unknown";
+      }
+    }
+
+    void Finish();
+  };  // SynthesizingEvent
+
+  SynthesizingEvent* mSynthesizingEvent;
+
+ public:
+  class Device {
+   public:
+    // SynTP is a touchpad driver of Synaptics.
+    class SynTP {
+     public:
+      static bool IsDriverInstalled() { return sMajorVersion != 0; }
+      /**
+       * GetDriverMajorVersion() returns the installed driver's major version.
+       * If SynTP driver isn't installed, this returns 0.
+       */
+      static int32_t GetDriverMajorVersion() { return sMajorVersion; }
+      /**
+       * GetDriverMinorVersion() returns the installed driver's minor version.
+       * If SynTP driver isn't installed, this returns -1.
+       */
+      static int32_t GetDriverMinorVersion() { return sMinorVersion; }
+
+      static void Init();
+
+     private:
+      static bool sInitialized;
+      static int32_t sMajorVersion;
+      static int32_t sMinorVersion;
+    };
+
+    class Elantech {
+     public:
+      /**
+       * GetDriverMajorVersion() returns the installed driver's major version.
+       * If Elantech's driver was installed, returns 0.
+       */
+      static int32_t GetDriverMajorVersion();
+
+      /**
+       * IsHelperWindow() checks whether aWnd is a helper window of Elantech's
+       * touchpad.  Returns TRUE if so.  Otherwise, FALSE.
+       */
+      static bool IsHelperWindow(HWND aWnd);
+
+      /**
+       * Key message handler for Elantech's hack.  Returns TRUE if the message
+       * is consumed by this handler.  Otherwise, FALSE.
+       */
+      static bool HandleKeyMessage(nsWindow* aWidget, UINT aMsg, WPARAM aWParam,
+                                   LPARAM aLParam);
+
+      static void UpdateZoomUntil();
+      static bool IsZooming();
+
+      static void Init();
+
+      static bool IsPinchHackNeeded() { return sUsePinchHack; }
+
+     private:
+      // Whether to enable the Elantech swipe gesture hack.
+      static bool sUseSwipeHack;
+      // Whether to enable the Elantech pinch-to-zoom gesture hack.
+      static bool sUsePinchHack;
+      static DWORD sZoomUntil;
+    };  // class Elantech
+
+    // Apoint is a touchpad driver of Alps.
+    class Apoint {
+     public:
+      static bool IsDriverInstalled() { return sMajorVersion != 0; }
+      /**
+       * GetDriverMajorVersion() returns the installed driver's major version.
+       * If Apoint driver isn't installed, this returns 0.
+       */
+      static int32_t GetDriverMajorVersion() { return sMajorVersion; }
+      /**
+       * GetDriverMinorVersion() returns the installed driver's minor version.
+       * If Apoint driver isn't installed, this returns -1.
+       */
+      static int32_t GetDriverMinorVersion() { return sMinorVersion; }
+
+      static void Init();
+
+     private:
+      static bool sInitialized;
+      static int32_t sMajorVersion;
+      static int32_t sMinorVersion;
+    };
+
+    class TrackPoint {
+     public:
+      /**
+       * IsDriverInstalled() returns TRUE if TrackPoint's driver is installed.
+       * Otherwise, returns FALSE.
+       */
+      static bool IsDriverInstalled();
+    };  // class TrackPoint
+
+    class UltraNav {
+     public:
+      /**
+       * IsObsoleteDriverInstalled() checks whether obsoleted UltraNav
+       * is installed on the environment.
+       * Returns TRUE if it was installed.  Otherwise, FALSE.
+       */
+      static bool IsObsoleteDriverInstalled();
+    };  // class UltraNav
+
+    class SetPoint {
+     public:
+      /**
+       * SetPoint, Logitech's mouse driver, may report wrong cursor position
+       * for WM_MOUSEHWHEEL message.  See comment in the implementation for
+       * the detail.
+       */
+      static bool IsGetMessagePosResponseValid(UINT aMessage, WPARAM aWParam,
+                                               LPARAM aLParam);
+
+     private:
+      static bool sMightBeUsing;
+    };
+
+    static void Init();
+
+    static bool IsFakeScrollableWindowNeeded() {
+      return sFakeScrollableWindowNeeded;
+    }
+
+   private:
+    /**
+     * Gets the bool value of aPrefName used to enable or disable an input
+     * workaround (like the Trackpoint hack).  The pref can take values 0 (for
+     * disabled), 1 (for enabled) or -1 (to automatically detect whether to
+     * enable the workaround).
+     *
+     * @param aPrefName The name of the pref.
+     * @param aValueIfAutomatic Whether the given input workaround should be
+     *                          enabled by default.
+     */
+    static bool GetWorkaroundPref(const char* aPrefName,
+                                  bool aValueIfAutomatic);
+
+    static bool sFakeScrollableWindowNeeded;
+  };  // class Device
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_WinMouseScrollHandler_h__
diff --git a/widget/windows/WinPointerEvents.cpp b/widget/windows/WinPointerEvents.cpp
new file mode 100644
index 0000000000..57e19a0c4b
--- /dev/null
+++ b/widget/windows/WinPointerEvents.cpp
@@ -0,0 +1,181 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * WinPointerEvents - Helper functions to retrieve PointerEvent's attributes
+ */
+
+#include "nscore.h"
+#include "nsWindowDefs.h"
+#include "WinPointerEvents.h"
+#include "WinUtils.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/dom/MouseEventBinding.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+const wchar_t WinPointerEvents::kPointerLibraryName[] = L"user32.dll";
+HMODULE WinPointerEvents::sLibraryHandle = nullptr;
+WinPointerEvents::GetPointerTypePtr WinPointerEvents::getPointerType = nullptr;
+WinPointerEvents::GetPointerInfoPtr WinPointerEvents::getPointerInfo = nullptr;
+WinPointerEvents::GetPointerPenInfoPtr WinPointerEvents::getPointerPenInfo =
+    nullptr;
+
+WinPointerEvents::WinPointerEvents() { InitLibrary(); }
+
+/* Load and shutdown */
+void WinPointerEvents::InitLibrary() {
+  MOZ_ASSERT(XRE_IsParentProcess());
+  if (getPointerType) {
+    // Return if we already initialized the PointerEvent related interfaces
+    return;
+  }
+  sLibraryHandle = ::LoadLibraryW(kPointerLibraryName);
+  MOZ_ASSERT(sLibraryHandle, "cannot load pointer library");
+  if (sLibraryHandle) {
+    getPointerType =
+        (GetPointerTypePtr)GetProcAddress(sLibraryHandle, "GetPointerType");
+    getPointerInfo =
+        (GetPointerInfoPtr)GetProcAddress(sLibraryHandle, "GetPointerInfo");
+    getPointerPenInfo = (GetPointerPenInfoPtr)GetProcAddress(
+        sLibraryHandle, "GetPointerPenInfo");
+  }
+
+  if (!getPointerType || !getPointerInfo || !getPointerPenInfo) {
+    MOZ_ASSERT(false, "get PointerEvent interfaces failed");
+    getPointerType = nullptr;
+    getPointerInfo = nullptr;
+    getPointerPenInfo = nullptr;
+    return;
+  }
+}
+
+bool WinPointerEvents::ShouldHandleWinPointerMessages(UINT aMsg,
+                                                      WPARAM aWParam) {
+  MOZ_ASSERT(aMsg == WM_POINTERDOWN || aMsg == WM_POINTERUP ||
+             aMsg == WM_POINTERUPDATE || aMsg == WM_POINTERLEAVE);
+  if (!sLibraryHandle) {
+    return false;
+  }
+
+  // We only handle WM_POINTER* when the input source is pen. This is because
+  // we need some information (e.g. tiltX, tiltY) which can't be retrieved by
+  // WM_*BUTTONDOWN.
+  uint32_t pointerId = GetPointerId(aWParam);
+  POINTER_INPUT_TYPE pointerType = PT_POINTER;
+  if (!GetPointerType(pointerId, &pointerType)) {
+    MOZ_ASSERT(false, "cannot find PointerType");
+    return false;
+  }
+  return (pointerType == PT_PEN);
+}
+
+bool WinPointerEvents::GetPointerType(uint32_t aPointerId,
+                                      POINTER_INPUT_TYPE* aPointerType) {
+  if (!getPointerType) {
+    return false;
+  }
+  return getPointerType(aPointerId, aPointerType);
+}
+
+POINTER_INPUT_TYPE
+WinPointerEvents::GetPointerType(uint32_t aPointerId) {
+  POINTER_INPUT_TYPE pointerType = PT_POINTER;
+  Unused << GetPointerType(aPointerId, &pointerType);
+  return pointerType;
+}
+
+bool WinPointerEvents::GetPointerInfo(uint32_t aPointerId,
+                                      POINTER_INFO* aPointerInfo) {
+  if (!getPointerInfo) {
+    return false;
+  }
+  return getPointerInfo(aPointerId, aPointerInfo);
+}
+
+bool WinPointerEvents::GetPointerPenInfo(uint32_t aPointerId,
+                                         POINTER_PEN_INFO* aPenInfo) {
+  if (!getPointerPenInfo) {
+    return false;
+  }
+  return getPointerPenInfo(aPointerId, aPenInfo);
+}
+
+bool WinPointerEvents::ShouldRollupOnPointerEvent(UINT aMsg, WPARAM aWParam) {
+  MOZ_ASSERT(aMsg == WM_POINTERDOWN);
+  // Only roll up popups when we handling WM_POINTER* to fire Gecko
+  // WidgetMouseEvent and suppress Windows WM_*BUTTONDOWN.
+  return ShouldHandleWinPointerMessages(aMsg, aWParam) &&
+         ShouldFirePointerEventByWinPointerMessages();
+}
+
+bool WinPointerEvents::ShouldFirePointerEventByWinPointerMessages() {
+  MOZ_ASSERT(sLibraryHandle);
+  return StaticPrefs::dom_w3c_pointer_events_dispatch_by_pointer_messages();
+}
+
+WinPointerInfo* WinPointerEvents::GetCachedPointerInfo(UINT aMsg,
+                                                       WPARAM aWParam) {
+  if (!sLibraryHandle ||
+      MOUSE_INPUT_SOURCE() != dom::MouseEvent_Binding::MOZ_SOURCE_PEN ||
+      ShouldFirePointerEventByWinPointerMessages()) {
+    return nullptr;
+  }
+  switch (aMsg) {
+    case WM_LBUTTONDOWN:
+    case WM_MBUTTONDOWN:
+    case WM_RBUTTONDOWN:
+      return &mPenPointerDownInfo;
+    case WM_LBUTTONUP:
+    case WM_MBUTTONUP:
+    case WM_RBUTTONUP:
+      return &mPenPointerDownInfo;
+    case WM_MOUSEMOVE:
+      return &mPenPointerUpdateInfo;
+    default:
+      MOZ_ASSERT(false);
+  }
+  return nullptr;
+}
+
+void WinPointerEvents::ConvertAndCachePointerInfo(UINT aMsg, WPARAM aWParam) {
+  MOZ_ASSERT(
+      !StaticPrefs::dom_w3c_pointer_events_dispatch_by_pointer_messages());
+  // Windows doesn't support chorded buttons for pen, so we can simply keep the
+  // latest information from pen generated pointer messages and use them when
+  // handling mouse messages. Used different pointer info for pointerdown,
+  // pointerupdate, and pointerup because Windows doesn't always interleave
+  // pointer messages and mouse messages.
+  switch (aMsg) {
+    case WM_POINTERDOWN:
+      ConvertAndCachePointerInfo(aWParam, &mPenPointerDownInfo);
+      break;
+    case WM_POINTERUP:
+      ConvertAndCachePointerInfo(aWParam, &mPenPointerUpInfo);
+      break;
+    case WM_POINTERUPDATE:
+      ConvertAndCachePointerInfo(aWParam, &mPenPointerUpdateInfo);
+      break;
+    default:
+      break;
+  }
+}
+
+void WinPointerEvents::ConvertAndCachePointerInfo(WPARAM aWParam,
+                                                  WinPointerInfo* aInfo) {
+  MOZ_ASSERT(
+      !StaticPrefs::dom_w3c_pointer_events_dispatch_by_pointer_messages());
+  aInfo->pointerId = GetPointerId(aWParam);
+  MOZ_ASSERT(GetPointerType(aInfo->pointerId) == PT_PEN);
+  POINTER_PEN_INFO penInfo;
+  GetPointerPenInfo(aInfo->pointerId, &penInfo);
+  aInfo->tiltX = penInfo.tiltX;
+  aInfo->tiltY = penInfo.tiltY;
+  // Windows defines the pen pressure is normalized to a range between 0 and
+  // 1024. Convert it to float.
+  aInfo->mPressure = penInfo.pressure ? (float)penInfo.pressure / 1024 : 0;
+}
diff --git a/widget/windows/WinPointerEvents.h b/widget/windows/WinPointerEvents.h
new file mode 100644
index 0000000000..94179e7b4e
--- /dev/null
+++ b/widget/windows/WinPointerEvents.h
@@ -0,0 +1,75 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WinPointerEvents_h__
+#define WinPointerEvents_h__
+
+#include "mozilla/MouseEvents.h"
+#include "touchinjection_sdk80.h"
+#include <windef.h>
+
+/******************************************************************************
+ * WinPointerInfo
+ *
+ * This is a helper class to handle WM_POINTER*. It only supports Win8 or later.
+ *
+ ******************************************************************************/
+class WinPointerInfo final : public mozilla::WidgetPointerHelper {
+ public:
+  WinPointerInfo() : WidgetPointerHelper(), mPressure(0), mButtons(0) {}
+
+  WinPointerInfo(uint32_t aPointerId, uint32_t aTiltX, uint32_t aTiltY,
+                 float aPressure, int16_t aButtons)
+      : WidgetPointerHelper(aPointerId, aTiltX, aTiltY),
+        mPressure(aPressure),
+        mButtons(aButtons) {}
+
+  float mPressure;
+  int16_t mButtons;
+};
+
+class WinPointerEvents final {
+ public:
+  explicit WinPointerEvents();
+
+ public:
+  bool ShouldHandleWinPointerMessages(UINT aMsg, WPARAM aWParam);
+
+  uint32_t GetPointerId(WPARAM aWParam) {
+    return GET_POINTERID_WPARAM(aWParam);
+  }
+  bool GetPointerType(uint32_t aPointerId, POINTER_INPUT_TYPE* aPointerType);
+  POINTER_INPUT_TYPE GetPointerType(uint32_t aPointerId);
+  bool GetPointerInfo(uint32_t aPointerId, POINTER_INFO* aPointerInfo);
+  bool GetPointerPenInfo(uint32_t aPointerId, POINTER_PEN_INFO* aPenInfo);
+  bool ShouldRollupOnPointerEvent(UINT aMsg, WPARAM aWParam);
+  bool ShouldFirePointerEventByWinPointerMessages();
+  WinPointerInfo* GetCachedPointerInfo(UINT aMsg, WPARAM aWParam);
+  void ConvertAndCachePointerInfo(UINT aMsg, WPARAM aWParam);
+  void ConvertAndCachePointerInfo(WPARAM aWParam, WinPointerInfo* aInfo);
+
+ private:
+  // Function prototypes
+  typedef BOOL(WINAPI* GetPointerTypePtr)(uint32_t aPointerId,
+                                          POINTER_INPUT_TYPE* aPointerType);
+  typedef BOOL(WINAPI* GetPointerInfoPtr)(uint32_t aPointerId,
+                                          POINTER_INFO* aPointerInfo);
+  typedef BOOL(WINAPI* GetPointerPenInfoPtr)(uint32_t aPointerId,
+                                             POINTER_PEN_INFO* aPenInfo);
+
+  void InitLibrary();
+
+  static HMODULE sLibraryHandle;
+  static const wchar_t kPointerLibraryName[];
+  // Static function pointers
+  static GetPointerTypePtr getPointerType;
+  static GetPointerInfoPtr getPointerInfo;
+  static GetPointerPenInfoPtr getPointerPenInfo;
+  WinPointerInfo mPenPointerDownInfo;
+  WinPointerInfo mPenPointerUpInfo;
+  WinPointerInfo mPenPointerUpdateInfo;
+};
+
+#endif  // #ifndef WinPointerEvents_h__
diff --git a/widget/windows/WinRegistry.cpp b/widget/windows/WinRegistry.cpp
new file mode 100644
index 0000000000..b04ae1df45
--- /dev/null
+++ b/widget/windows/WinRegistry.cpp
@@ -0,0 +1,325 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WinRegistry.h"
+#include "nsThreadUtils.h"
+
+namespace mozilla::widget::WinRegistry {
+
+Key::Key(HKEY aParent, const nsString& aPath, KeyMode aMode, CreateFlag) {
+  MOZ_ASSERT(aParent);
+  DWORD disposition;
+  ::RegCreateKeyExW(aParent, aPath.get(), 0, nullptr, REG_OPTION_NON_VOLATILE,
+                    (REGSAM)aMode, nullptr, &mKey, &disposition);
+}
+
+Key::Key(HKEY aParent, const nsString& aPath, KeyMode aMode) {
+  MOZ_ASSERT(aParent);
+  ::RegOpenKeyExW(aParent, aPath.get(), 0, (REGSAM)aMode, &mKey);
+}
+
+uint32_t Key::GetChildCount() const {
+  MOZ_ASSERT(mKey);
+  DWORD result = 0;
+  ::RegQueryInfoKeyW(mKey, nullptr, nullptr, nullptr, &result, nullptr, nullptr,
+                     nullptr, nullptr, nullptr, nullptr, nullptr);
+  return result;
+}
+
+bool Key::GetChildName(uint32_t aIndex, nsAString& aResult) const {
+  MOZ_ASSERT(mKey);
+  FILETIME lastWritten;
+
+  wchar_t nameBuf[kMaxKeyNameLen + 1];
+  DWORD nameLen = std::size(nameBuf);
+
+  LONG rv = RegEnumKeyExW(mKey, aIndex, nameBuf, &nameLen, nullptr, nullptr,
+                          nullptr, &lastWritten);
+  if (rv != ERROR_SUCCESS) {
+    return false;
+  }
+  aResult.Assign(nameBuf, nameLen);
+  return true;
+}
+
+bool Key::RemoveChildKey(const nsString& aName) const {
+  MOZ_ASSERT(mKey);
+  return SUCCEEDED(RegDeleteKeyW(mKey, aName.get()));
+}
+
+uint32_t Key::GetValueCount() const {
+  MOZ_ASSERT(mKey);
+  DWORD result = 0;
+  ::RegQueryInfoKeyW(mKey, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
+                     &result, nullptr, nullptr, nullptr, nullptr);
+  return result;
+}
+
+bool Key::GetValueName(uint32_t aIndex, nsAString& aResult) const {
+  MOZ_ASSERT(mKey);
+  wchar_t nameBuf[kMaxValueNameLen + 1];
+  DWORD nameLen = std::size(nameBuf);
+
+  LONG rv = RegEnumValueW(mKey, aIndex, nameBuf, &nameLen, nullptr, nullptr,
+                          nullptr, nullptr);
+  if (rv != ERROR_SUCCESS) {
+    return false;
+  }
+  aResult.Assign(nameBuf, nameLen);
+  return true;
+}
+
+ValueType Key::GetValueType(const nsString& aName) const {
+  MOZ_ASSERT(mKey);
+  DWORD result;
+  LONG rv =
+      RegQueryValueExW(mKey, aName.get(), nullptr, &result, nullptr, nullptr);
+  return SUCCEEDED(rv) ? ValueType(result) : ValueType::None;
+}
+
+bool Key::RemoveValue(const nsString& aName) const {
+  MOZ_ASSERT(mKey);
+  return SUCCEEDED(RegDeleteValueW(mKey, aName.get()));
+}
+
+Maybe<uint32_t> Key::GetValueAsDword(const nsString& aName) const {
+  MOZ_ASSERT(mKey);
+  DWORD type;
+  DWORD value = 0;
+  DWORD size = sizeof(DWORD);
+  HRESULT rv = RegQueryValueExW(mKey, aName.get(), nullptr, &type,
+                                (LPBYTE)&value, &size);
+  if (FAILED(rv) || type != REG_DWORD) {
+    return Nothing();
+  }
+  return Some(value);
+}
+
+bool Key::WriteValueAsDword(const nsString& aName, uint32_t aValue) {
+  MOZ_ASSERT(mKey);
+  return SUCCEEDED(RegSetValueExW(mKey, aName.get(), 0, REG_DWORD,
+                                  (const BYTE*)&aValue, sizeof(aValue)));
+}
+
+Maybe<uint64_t> Key::GetValueAsQword(const nsString& aName) const {
+  MOZ_ASSERT(mKey);
+  DWORD type;
+  uint64_t value = 0;
+  DWORD size = sizeof(uint64_t);
+  HRESULT rv = RegQueryValueExW(mKey, aName.get(), nullptr, &type,
+                                (LPBYTE)&value, &size);
+  if (FAILED(rv) || type != REG_QWORD) {
+    return Nothing();
+  }
+  return Some(value);
+}
+
+bool Key::WriteValueAsQword(const nsString& aName, uint64_t aValue) {
+  MOZ_ASSERT(mKey);
+  return SUCCEEDED(RegSetValueExW(mKey, aName.get(), 0, REG_QWORD,
+                                  (const BYTE*)&aValue, sizeof(aValue)));
+}
+
+bool Key::GetValueAsBinary(const nsString& aName,
+                           nsTArray<uint8_t>& aResult) const {
+  MOZ_ASSERT(mKey);
+  DWORD type;
+  DWORD size;
+  LONG rv = RegQueryValueExW(mKey, aName.get(), nullptr, &type, nullptr, &size);
+  if (FAILED(rv) || type != REG_BINARY) {
+    return false;
+  }
+  if (!aResult.SetLength(size, fallible)) {
+    return false;
+  }
+  rv = RegQueryValueExW(mKey, aName.get(), nullptr, nullptr, aResult.Elements(),
+                        &size);
+  return SUCCEEDED(rv);
+}
+
+Maybe<nsTArray<uint8_t>> Key::GetValueAsBinary(const nsString& aName) const {
+  nsTArray<uint8_t> value;
+  Maybe<nsTArray<uint8_t>> result;
+  if (GetValueAsBinary(aName, value)) {
+    result.emplace(std::move(value));
+  }
+  return result;
+}
+
+bool Key::WriteValueAsBinary(const nsString& aName,
+                             Span<const uint8_t> aValue) {
+  MOZ_ASSERT(mKey);
+  return SUCCEEDED(RegSetValueExW(mKey, aName.get(), 0, REG_BINARY,
+                                  (const BYTE*)aValue.data(), aValue.size()));
+}
+
+static bool IsStringType(DWORD aType, StringFlags aFlags) {
+  switch (aType) {
+    case REG_SZ:
+      return bool(aFlags & StringFlags::Sz);
+    case REG_EXPAND_SZ:
+      return bool(aFlags & StringFlags::ExpandSz);
+    case REG_MULTI_SZ:
+      return bool(aFlags & StringFlags::LegacyMultiSz);
+    default:
+      return false;
+  }
+}
+
+bool Key::GetValueAsString(const nsString& aName, nsString& aResult,
+                           StringFlags aFlags) const {
+  MOZ_ASSERT(mKey);
+  DWORD type;
+  DWORD size;
+  LONG rv = RegQueryValueExW(mKey, aName.get(), nullptr, &type, nullptr, &size);
+  if (FAILED(rv) || !IsStringType(type, aFlags)) {
+    return false;
+  }
+  if (!size) {
+    aResult.Truncate();
+    return true;
+  }
+  // The buffer size must be a multiple of 2.
+  if (NS_WARN_IF(size % 2 != 0)) {
+    return false;
+  }
+  size_t resultLen = size / 2;
+  {
+    auto handleOrError =
+        aResult.BulkWrite(resultLen, 0, /* aAllowShrinking = */ false);
+    if (NS_WARN_IF(handleOrError.isErr())) {
+      return false;
+    }
+    auto handle = handleOrError.unwrap();
+    auto len = GetValueAsString(aName, {handle.Elements(), handle.Length() + 1},
+                                aFlags & ~StringFlags::ExpandEnvironment);
+    if (NS_WARN_IF(!len)) {
+      return false;
+    }
+    handle.Finish(*len, /* aAllowShrinking = */ false);
+    if (*len && !aResult.CharAt(*len - 1)) {
+      // The string passed to us had a null terminator in the final
+      // position.
+      aResult.Truncate(*len - 1);
+    }
+  }
+  if (type == REG_EXPAND_SZ && (aFlags & StringFlags::ExpandEnvironment)) {
+    resultLen = ExpandEnvironmentStringsW(aResult.get(), nullptr, 0);
+    if (resultLen > 1) {
+      nsString expandedResult;
+      // |resultLen| includes the terminating null character
+      resultLen--;
+      if (!expandedResult.SetLength(resultLen, fallible)) {
+        return false;
+      }
+      resultLen = ExpandEnvironmentStringsW(aResult.get(), expandedResult.get(),
+                                            resultLen + 1);
+      if (resultLen <= 0) {
+        return false;
+      }
+      aResult = std::move(expandedResult);
+    } else if (resultLen == 1) {
+      // It apparently expands to nothing (just a null terminator).
+      resultLen = 0;
+      aResult.Truncate();
+    }
+  }
+  return true;
+}
+
+Maybe<nsString> Key::GetValueAsString(const nsString& aName,
+                                      StringFlags aFlags) const {
+  nsString value;
+  Maybe<nsString> result;
+  if (GetValueAsString(aName, value, aFlags)) {
+    result.emplace(std::move(value));
+  }
+  return result;
+}
+
+Maybe<uint32_t> Key::GetValueAsString(const nsString& aName,
+                                      Span<char16_t> aBuffer,
+                                      StringFlags aFlags) const {
+  MOZ_ASSERT(mKey);
+  MOZ_ASSERT(aBuffer.Length(), "Empty buffer?");
+  MOZ_ASSERT(!(aFlags & StringFlags::ExpandEnvironment),
+             "Environment expansion not performed on a single buffer");
+
+  DWORD size = aBuffer.LengthBytes();
+  DWORD type;
+  HRESULT rv = RegQueryValueExW(mKey, aName.get(), nullptr, &type,
+                                (LPBYTE)aBuffer.data(), &size);
+  if (FAILED(rv)) {
+    return Nothing();
+  }
+  if (!IsStringType(type, aFlags)) {
+    return Nothing();
+  }
+  uint32_t len = size ? size / sizeof(char16_t) - 1 : 0;
+  aBuffer[len] = 0;
+  return Some(len);
+}
+
+KeyWatcher::KeyWatcher(Key&& aKey,
+                       nsISerialEventTarget* aTargetSerialEventTarget,
+                       Callback&& aCallback)
+    : mKey(std::move(aKey)),
+      mEventTarget(aTargetSerialEventTarget),
+      mCallback(std::move(aCallback)) {
+  MOZ_ASSERT(mKey);
+  MOZ_ASSERT(mEventTarget);
+  MOZ_ASSERT(mCallback);
+  mEvent = CreateEvent(nullptr, /* bManualReset = */ FALSE,
+                       /* bInitialState = */ FALSE, nullptr);
+  if (NS_WARN_IF(!mEvent)) {
+    return;
+  }
+
+  if (NS_WARN_IF(!Register())) {
+    return;
+  }
+
+  // The callback only dispatches to the relevant event target, so we can use
+  // WT_EXECUTEINWAITTHREAD.
+  RegisterWaitForSingleObject(&mWaitObject, mEvent, WatchCallback, this,
+                              INFINITE, WT_EXECUTEINWAITTHREAD);
+}
+
+void KeyWatcher::WatchCallback(void* aContext, BOOLEAN) {
+  auto* watcher = static_cast<KeyWatcher*>(aContext);
+  watcher->Register();
+  watcher->mEventTarget->Dispatch(
+      NS_NewRunnableFunction("KeyWatcher callback", watcher->mCallback));
+}
+
+// As per the documentation in:
+// https://learn.microsoft.com/en-us/windows/win32/api/winreg/nf-winreg-regnotifychangekeyvalue
+//
+// This function detects a single change. After the caller receives a
+// notification event, it should call the function again to receive the next
+// notification.
+bool KeyWatcher::Register() {
+  MOZ_ASSERT(mEvent);
+  DWORD flags = REG_NOTIFY_CHANGE_NAME | REG_NOTIFY_CHANGE_ATTRIBUTES |
+                REG_NOTIFY_CHANGE_LAST_SET | REG_NOTIFY_CHANGE_SECURITY |
+                REG_NOTIFY_THREAD_AGNOSTIC;
+  HRESULT rv =
+      RegNotifyChangeKeyValue(mKey.RawKey(), /* bWatchSubtree = */ TRUE, flags,
+                              mEvent, /* fAsynchronous = */ TRUE);
+  return !NS_WARN_IF(FAILED(rv));
+}
+
+KeyWatcher::~KeyWatcher() {
+  if (mWaitObject) {
+    UnregisterWait(mWaitObject);
+    CloseHandle(mWaitObject);
+  }
+  if (mEvent) {
+    CloseHandle(mEvent);
+  }
+}
+
+}  // namespace mozilla::widget::WinRegistry
diff --git a/widget/windows/WinRegistry.h b/widget/windows/WinRegistry.h
new file mode 100644
index 0000000000..8ab221928e
--- /dev/null
+++ b/widget/windows/WinRegistry.h
@@ -0,0 +1,235 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_WinRegistry_h__
+#define mozilla_widget_WinRegistry_h__
+
+#include <windows.h>
+#include <functional>
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/Span.h"
+
+class nsISerialEventTarget;
+
+namespace mozilla::widget::WinRegistry {
+
+// According to MSDN, the following limits apply (in characters excluding room
+// for terminating null character):
+static constexpr size_t kMaxKeyNameLen = 255;
+static constexpr size_t kMaxValueNameLen = 16383;
+
+/// https://learn.microsoft.com/en-us/windows/win32/shell/regsam
+enum class KeyMode : uint32_t {
+  AllAccess = KEY_ALL_ACCESS,
+  QueryValue = KEY_QUERY_VALUE,
+  CreateLink = KEY_CREATE_LINK,
+  CreateSubKey = KEY_CREATE_SUB_KEY,
+  EnumerateSubkeys = KEY_ENUMERATE_SUB_KEYS,
+  Execute = KEY_EXECUTE,
+  Notify = KEY_NOTIFY,
+  Read = KEY_READ,
+  SetValue = KEY_SET_VALUE,
+  Write = KEY_WRITE,
+};
+
+MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(KeyMode);
+
+enum class StringFlags : uint32_t {
+  // Whether to allow REG_SZ strings.
+  Sz = 1 << 0,
+  // Whether to read EXPAND_SZ strings.
+  ExpandSz = 1 << 1,
+  // Whether to treat MULTI_SZ values as strings. This is a historical
+  // idiosyncrasy of the nsIWindowsRegKey, but most likely not what you want.
+  LegacyMultiSz = 1 << 2,
+  // Whether to expand environment variables in EXPAND_SZ values.
+  // Only makes sense along with the ExpandSz variable.
+  ExpandEnvironment = 1 << 3,
+  // By default, only allow regular Sz, and don't perform environment expansion.
+  Default = Sz,
+};
+
+MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(StringFlags);
+
+// Convenience alias for legacy WinUtils callers, to preserve behavior.
+// Chances are users of these flags could just look at Sz strings, tho.
+static constexpr auto kLegacyWinUtilsStringFlags =
+    StringFlags::Sz | StringFlags::ExpandSz;
+
+// https://learn.microsoft.com/en-us/windows/win32/sysinfo/registry-value-types
+enum class ValueType : uint32_t {
+  Binary = REG_BINARY,
+  Dword = REG_DWORD,
+  ExpandSz = REG_EXPAND_SZ,
+  Link = REG_LINK,
+  MultiSz = REG_MULTI_SZ,
+  None = REG_NONE,
+  Qword = REG_QWORD,
+  Sz = REG_SZ,
+};
+
+class Key {
+ public:
+  enum CreateFlag {
+    Create,
+  };
+
+  Key() = default;
+  Key(const Key&) = delete;
+  Key(Key&& aOther) { std::swap(mKey, aOther.mKey); }
+
+  Key& operator=(const Key&) = delete;
+  Key& operator=(Key&& aOther) {
+    std::swap(mKey, aOther.mKey);
+    return *this;
+  }
+
+  Key(HKEY aParent, const nsString& aPath, KeyMode aMode, CreateFlag);
+  Key(HKEY aParent, const nsString& aPath, KeyMode aMode);
+
+  Key(const Key& aParent, const nsString& aPath, KeyMode aMode, CreateFlag)
+      : Key(aParent.mKey, aPath, aMode, Create) {}
+  Key(const Key& aParent, const nsString& aPath, KeyMode aMode)
+      : Key(aParent.mKey, aPath, aMode) {}
+
+  ~Key() {
+    if (mKey) {
+      ::RegCloseKey(mKey);
+    }
+  }
+
+  explicit operator bool() const { return !!mKey; }
+
+  uint32_t GetChildCount() const;
+  [[nodiscard]] bool GetChildName(uint32_t aIndex, nsAString& aResult) const;
+  [[nodiscard]] bool RemoveChildKey(const nsString& aName) const;
+
+  uint32_t GetValueCount() const;
+  [[nodiscard]] bool GetValueName(uint32_t aIndex, nsAString& aResult) const;
+  ValueType GetValueType(const nsString& aName) const;
+  bool RemoveValue(const nsString& aName) const;
+
+  Maybe<uint32_t> GetValueAsDword(const nsString& aName) const;
+  bool WriteValueAsDword(const nsString& aName, uint32_t aValue);
+
+  Maybe<uint64_t> GetValueAsQword(const nsString& aName) const;
+  [[nodiscard]] bool WriteValueAsQword(const nsString& aName, uint64_t aValue);
+
+  [[nodiscard]] bool GetValueAsBinary(const nsString& aName,
+                                      nsTArray<uint8_t>&) const;
+  Maybe<nsTArray<uint8_t>> GetValueAsBinary(const nsString& aName) const;
+  [[nodiscard]] bool WriteValueAsBinary(const nsString& aName,
+                                        Span<const uint8_t> aValue);
+
+  [[nodiscard]] bool GetValueAsString(const nsString& aName, nsString& aResult,
+                                      StringFlags = StringFlags::Default) const;
+  Maybe<nsString> GetValueAsString(const nsString& aName,
+                                   StringFlags = StringFlags::Default) const;
+  // Reads a string value into a buffer. Returns Some(length) if the string is
+  // read fully, in which case the passed memory region contains a
+  // null-terminated string.
+  // Doesn't perform environment expansion (and asserts if you pass the
+  // ExpandEnvironment flag).
+  [[nodiscard]] Maybe<uint32_t> GetValueAsString(
+      const nsString& aName, Span<char16_t>,
+      StringFlags = StringFlags::Default) const;
+  [[nodiscard]] Maybe<uint32_t> GetValueAsString(
+      const nsString& aName, Span<wchar_t> aBuffer,
+      StringFlags aFlags = StringFlags::Default) const {
+    return GetValueAsString(
+        aName, Span<char16_t>((char16_t*)aBuffer.data(), aBuffer.Length()),
+        aFlags);
+  }
+
+  [[nodiscard]] bool WriteValueAsString(const nsString& aName,
+                                        const nsString& aValue) {
+    MOZ_ASSERT(mKey);
+    return SUCCEEDED(RegSetValueExW(mKey, aName.get(), 0, REG_SZ,
+                                    (const BYTE*)aValue.get(),
+                                    (aValue.Length() + 1) * sizeof(char16_t)));
+  }
+
+  HKEY RawKey() const { return mKey; }
+
+ private:
+  HKEY mKey = nullptr;
+};
+
+inline bool HasKey(HKEY aRootKey, const nsString& aKeyName) {
+  return !!Key(aRootKey, aKeyName, KeyMode::Read);
+}
+
+// Returns a single string value from the registry into a buffer.
+[[nodiscard]] inline bool GetString(HKEY aRootKey, const nsString& aKeyName,
+                                    const nsString& aValueName,
+                                    Span<char16_t> aBuffer,
+                                    StringFlags aFlags = StringFlags::Default) {
+  Key k(aRootKey, aKeyName, KeyMode::QueryValue);
+  return k && k.GetValueAsString(aValueName, aBuffer, aFlags);
+}
+[[nodiscard]] inline bool GetString(HKEY aRootKey, const nsString& aKeyName,
+                                    const nsString& aValueName,
+                                    Span<wchar_t> aBuffer,
+                                    StringFlags aFlags = StringFlags::Default) {
+  return GetString(aRootKey, aKeyName, aValueName,
+                   Span<char16_t>((char16_t*)aBuffer.data(), aBuffer.Length()),
+                   aFlags);
+}
+[[nodiscard]] inline bool GetString(HKEY aRootKey, const nsString& aKeyName,
+                                    const nsString& aValueName,
+                                    nsString& aBuffer,
+                                    StringFlags aFlags = StringFlags::Default) {
+  Key k(aRootKey, aKeyName, KeyMode::QueryValue);
+  return k && k.GetValueAsString(aValueName, aBuffer, aFlags);
+}
+inline Maybe<nsString> GetString(HKEY aRootKey, const nsString& aKeyName,
+                                 const nsString& aValueName,
+                                 StringFlags aFlags = StringFlags::Default) {
+  Key k(aRootKey, aKeyName, KeyMode::QueryValue);
+  if (!k) {
+    return Nothing();
+  }
+  return k.GetValueAsString(aValueName, aFlags);
+}
+
+class KeyWatcher final {
+ public:
+  using Callback = std::function<void()>;
+
+  KeyWatcher(const KeyWatcher&) = delete;
+
+  const Key& GetKey() const { return mKey; }
+
+  // Start watching a key. The watching is recursive (the whole key subtree is
+  // watched), and the callback is executed every time the key or any of its
+  // descendants change until the watcher is destroyed.
+  //
+  // @param aKey the key to watch. Must have been opened with the
+  //             KeyMode::Notify flag.
+  // @param aTargetSerialEventTarget the target event target to dispatch the
+  //        callback to.
+  // @param aCallback the closure to run every time that registry key changes.
+  KeyWatcher(Key&& aKey, nsISerialEventTarget* aTargetSerialEventTarget,
+             Callback&& aCallback);
+
+  ~KeyWatcher();
+
+ private:
+  static void CALLBACK WatchCallback(void* aContext, BOOLEAN);
+  bool Register();
+
+  Key mKey;
+  nsCOMPtr<nsISerialEventTarget> mEventTarget;
+  Callback mCallback;
+  HANDLE mEvent = nullptr;
+  HANDLE mWaitObject = nullptr;
+};
+
+}  // namespace mozilla::widget::WinRegistry
+
+#endif
diff --git a/widget/windows/WinTaskbar.cpp b/widget/windows/WinTaskbar.cpp
new file mode 100644
index 0000000000..56608503da
--- /dev/null
+++ b/widget/windows/WinTaskbar.cpp
@@ -0,0 +1,493 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIWinTaskbar.h"
+#include "WinTaskbar.h"
+#include "TaskbarPreview.h"
+#include "nsITaskbarPreviewController.h"
+
+#include "mozilla/RefPtr.h"
+#include "mozilla/widget/JumpListBuilder.h"
+#include <nsError.h>
+#include <nsCOMPtr.h>
+#include <nsIWidget.h>
+#include <nsIBaseWindow.h>
+#include <nsServiceManagerUtils.h>
+#include "nsIXULAppInfo.h"
+#include "nsILegacyJumpListBuilder.h"
+#include "nsUXThemeData.h"
+#include "nsWindow.h"
+#include "WinUtils.h"
+#include "TaskbarTabPreview.h"
+#include "TaskbarWindowPreview.h"
+#include "LegacyJumpListBuilder.h"
+#include "nsWidgetsCID.h"
+#include "nsPIDOMWindow.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "mozilla/Preferences.h"
+#include "nsAppRunner.h"
+#include "nsXREDirProvider.h"
+#include "mozilla/widget/WinRegistry.h"
+#include <io.h>
+#include <propvarutil.h>
+#include <propkey.h>
+#include <shellapi.h>
+
+static NS_DEFINE_CID(kLegacyJumpListBuilderCID,
+                     NS_WIN_LEGACYJUMPLISTBUILDER_CID);
+
+namespace {
+
+HWND GetHWNDFromDocShell(nsIDocShell* aShell) {
+  nsCOMPtr<nsIBaseWindow> baseWindow(
+      do_QueryInterface(reinterpret_cast<nsISupports*>(aShell)));
+
+  if (!baseWindow) return nullptr;
+
+  nsCOMPtr<nsIWidget> widget;
+  baseWindow->GetMainWidget(getter_AddRefs(widget));
+
+  return widget ? (HWND)widget->GetNativeData(NS_NATIVE_WINDOW) : nullptr;
+}
+
+HWND GetHWNDFromDOMWindow(mozIDOMWindow* dw) {
+  nsCOMPtr<nsIWidget> widget;
+
+  if (!dw) return nullptr;
+
+  nsCOMPtr<nsPIDOMWindowInner> window = nsPIDOMWindowInner::From(dw);
+  return GetHWNDFromDocShell(window->GetDocShell());
+}
+
+nsresult SetWindowAppUserModelProp(mozIDOMWindow* aParent,
+                                   const nsString& aIdentifier) {
+  NS_ENSURE_ARG_POINTER(aParent);
+
+  if (aIdentifier.IsEmpty()) return NS_ERROR_INVALID_ARG;
+
+  HWND toplevelHWND = ::GetAncestor(GetHWNDFromDOMWindow(aParent), GA_ROOT);
+
+  if (!toplevelHWND) return NS_ERROR_INVALID_ARG;
+
+  RefPtr<IPropertyStore> pPropStore;
+  if (FAILED(SHGetPropertyStoreForWindow(toplevelHWND, IID_IPropertyStore,
+                                         getter_AddRefs(pPropStore)))) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  PROPVARIANT pv;
+  if (FAILED(InitPropVariantFromString(aIdentifier.get(), &pv))) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsresult rv = NS_OK;
+  if (FAILED(pPropStore->SetValue(PKEY_AppUserModel_ID, pv)) ||
+      FAILED(pPropStore->Commit())) {
+    rv = NS_ERROR_FAILURE;
+  }
+
+  PropVariantClear(&pv);
+
+  return rv;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// default nsITaskbarPreviewController
+
+class DefaultController final : public nsITaskbarPreviewController {
+  ~DefaultController() {}
+  HWND mWnd;
+
+ public:
+  explicit DefaultController(HWND hWnd) : mWnd(hWnd) {}
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITASKBARPREVIEWCONTROLLER
+};
+
+NS_IMETHODIMP
+DefaultController::GetWidth(uint32_t* aWidth) {
+  RECT r;
+  ::GetClientRect(mWnd, &r);
+  *aWidth = r.right;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+DefaultController::GetHeight(uint32_t* aHeight) {
+  RECT r;
+  ::GetClientRect(mWnd, &r);
+  *aHeight = r.bottom;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+DefaultController::GetThumbnailAspectRatio(float* aThumbnailAspectRatio) {
+  uint32_t width, height;
+  GetWidth(&width);
+  GetHeight(&height);
+  if (!height) height = 1;
+
+  *aThumbnailAspectRatio = width / float(height);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+DefaultController::RequestThumbnail(nsITaskbarPreviewCallback* aCallback,
+                                    uint32_t width, uint32_t height) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+DefaultController::RequestPreview(nsITaskbarPreviewCallback* aCallback) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+DefaultController::OnClose(void) {
+  MOZ_ASSERT_UNREACHABLE(
+      "OnClose should not be called for "
+      "TaskbarWindowPreviews");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+DefaultController::OnActivate(bool* rAcceptActivation) {
+  *rAcceptActivation = true;
+  MOZ_ASSERT_UNREACHABLE(
+      "OnActivate should not be called for "
+      "TaskbarWindowPreviews");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+DefaultController::OnClick(nsITaskbarPreviewButton* button) { return NS_OK; }
+
+NS_IMPL_ISUPPORTS(DefaultController, nsITaskbarPreviewController)
+}  // namespace
+
+namespace mozilla {
+namespace widget {
+
+///////////////////////////////////////////////////////////////////////////////
+// nsIWinTaskbar
+
+NS_IMPL_ISUPPORTS(WinTaskbar, nsIWinTaskbar)
+
+bool WinTaskbar::Initialize() {
+  if (mTaskbar) return true;
+
+  ::CoInitialize(nullptr);
+  HRESULT hr =
+      ::CoCreateInstance(CLSID_TaskbarList, nullptr, CLSCTX_INPROC_SERVER,
+                         IID_ITaskbarList4, (void**)&mTaskbar);
+  if (FAILED(hr)) return false;
+
+  hr = mTaskbar->HrInit();
+  if (FAILED(hr)) {
+    // This may fail with shell extensions like blackbox installed.
+    NS_WARNING("Unable to initialize taskbar");
+    NS_RELEASE(mTaskbar);
+    return false;
+  }
+  return true;
+}
+
+WinTaskbar::WinTaskbar() : mTaskbar(nullptr) {}
+
+WinTaskbar::~WinTaskbar() {
+  if (mTaskbar) {  // match successful Initialize() call
+    NS_RELEASE(mTaskbar);
+    ::CoUninitialize();
+  }
+}
+
+// static
+bool WinTaskbar::GenerateAppUserModelID(nsAString& aAppUserModelId,
+                                        bool aPrivateBrowsing) {
+  // If marked as such in prefs, use a hash of the profile path for the id
+  // instead of the install path hash setup by the installer.
+  if (Preferences::GetBool("taskbar.grouping.useprofile", false)) {
+    nsCOMPtr<nsIFile> profileDir;
+    NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                           getter_AddRefs(profileDir));
+    bool exists = false;
+    if (profileDir && NS_SUCCEEDED(profileDir->Exists(&exists)) && exists) {
+      nsAutoCString path;
+      if (NS_SUCCEEDED(profileDir->GetPersistentDescriptor(path))) {
+        nsAutoString id;
+        id.AppendInt(HashString(path));
+        if (!id.IsEmpty()) {
+          aAppUserModelId.Assign(id);
+          return true;
+        }
+      }
+    }
+  }
+
+  // The default value is set by the installer and is stored in the registry
+  // under (HKLM||HKCU)/Software/Mozilla/Firefox/TaskBarIDs. If for any reason
+  // hash generation operation fails, the installer will not store a value in
+  // the registry or set ids on shortcuts. A lack of an id can also occur for
+  // zipped builds.
+  nsCOMPtr<nsIXULAppInfo> appInfo =
+      do_GetService("@mozilla.org/xre/app-info;1");
+  nsCString appName;
+  if (appInfo && NS_SUCCEEDED(appInfo->GetName(appName))) {
+    nsAutoString regKey;
+    regKey.AssignLiteral("Software\\Mozilla\\");
+    AppendASCIItoUTF16(appName, regKey);
+    regKey.AppendLiteral("\\TaskBarIDs");
+
+    WCHAR path[MAX_PATH];
+    if (GetModuleFileNameW(nullptr, path, MAX_PATH)) {
+      wchar_t* slash = wcsrchr(path, '\\');
+      if (!slash) return false;
+      *slash = '\0';  // no trailing slash
+
+      nsDependentString pathStr(path);
+      for (auto* rootKey : {HKEY_LOCAL_MACHINE, HKEY_CURRENT_USER}) {
+        if (auto aumid = WinRegistry::GetString(rootKey, regKey, pathStr)) {
+          aAppUserModelId = std::move(*aumid);
+          break;
+        }
+      }
+    }
+  }
+
+  // If we haven't found an ID yet then use the install hash. In xpcshell tests
+  // the directory provider may not have been initialized so bypass in this
+  // case.
+  if (aAppUserModelId.IsEmpty() && gDirServiceProvider) {
+    gDirServiceProvider->GetInstallHash(aAppUserModelId);
+  }
+
+  if (aPrivateBrowsing) {
+    aAppUserModelId.AppendLiteral(";PrivateBrowsingAUMID");
+  }
+
+  return !aAppUserModelId.IsEmpty();
+}
+
+// static
+bool WinTaskbar::GetAppUserModelID(nsAString& aAppUserModelId,
+                                   bool aPrivateBrowsing) {
+  // If an ID has already been set then use that.
+  PWSTR id;
+  if (SUCCEEDED(GetCurrentProcessExplicitAppUserModelID(&id))) {
+    aAppUserModelId.Assign(id);
+    CoTaskMemFree(id);
+  }
+
+  return GenerateAppUserModelID(aAppUserModelId, aPrivateBrowsing);
+}
+
+NS_IMETHODIMP
+WinTaskbar::GetDefaultGroupId(nsAString& aDefaultGroupId) {
+  if (!GetAppUserModelID(aDefaultGroupId)) return NS_ERROR_UNEXPECTED;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WinTaskbar::GetDefaultPrivateGroupId(nsAString& aDefaultPrivateGroupId) {
+  if (!GetAppUserModelID(aDefaultPrivateGroupId, true))
+    return NS_ERROR_UNEXPECTED;
+
+  return NS_OK;
+}
+
+// (static) Called from AppShell
+bool WinTaskbar::RegisterAppUserModelID() {
+  nsAutoString uid;
+  if (!GetAppUserModelID(uid)) return false;
+
+  return SUCCEEDED(SetCurrentProcessExplicitAppUserModelID(uid.get()));
+}
+
+NS_IMETHODIMP
+WinTaskbar::GetAvailable(bool* aAvailable) {
+  // ITaskbarList4::HrInit() may fail with shell extensions like blackbox
+  // installed. Initialize early to return available=false in those cases.
+  *aAvailable = Initialize();
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WinTaskbar::CreateTaskbarTabPreview(nsIDocShell* shell,
+                                    nsITaskbarPreviewController* controller,
+                                    nsITaskbarTabPreview** _retval) {
+  if (!Initialize()) return NS_ERROR_NOT_AVAILABLE;
+
+  NS_ENSURE_ARG_POINTER(shell);
+  NS_ENSURE_ARG_POINTER(controller);
+
+  HWND toplevelHWND = ::GetAncestor(GetHWNDFromDocShell(shell), GA_ROOT);
+
+  if (!toplevelHWND) return NS_ERROR_INVALID_ARG;
+
+  RefPtr<TaskbarTabPreview> preview(
+      new TaskbarTabPreview(mTaskbar, controller, toplevelHWND, shell));
+  if (!preview) return NS_ERROR_OUT_OF_MEMORY;
+
+  nsresult rv = preview->Init();
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  preview.forget(_retval);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WinTaskbar::GetTaskbarWindowPreview(nsIDocShell* shell,
+                                    nsITaskbarWindowPreview** _retval) {
+  if (!Initialize()) return NS_ERROR_NOT_AVAILABLE;
+
+  NS_ENSURE_ARG_POINTER(shell);
+
+  HWND toplevelHWND = ::GetAncestor(GetHWNDFromDocShell(shell), GA_ROOT);
+
+  if (!toplevelHWND) return NS_ERROR_INVALID_ARG;
+
+  nsWindow* window = WinUtils::GetNSWindowPtr(toplevelHWND);
+
+  if (!window) return NS_ERROR_FAILURE;
+
+  nsCOMPtr<nsITaskbarWindowPreview> preview = window->GetTaskbarPreview();
+  if (!preview) {
+    RefPtr<DefaultController> defaultController =
+        new DefaultController(toplevelHWND);
+
+    TaskbarWindowPreview* previewRaw = new TaskbarWindowPreview(
+        mTaskbar, defaultController, toplevelHWND, shell);
+    if (!previewRaw) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    preview = previewRaw;
+
+    nsresult rv = previewRaw->Init();
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+    window->SetTaskbarPreview(preview);
+  }
+
+  preview.forget(_retval);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WinTaskbar::GetTaskbarProgress(nsIDocShell* shell,
+                               nsITaskbarProgress** _retval) {
+  nsCOMPtr<nsITaskbarWindowPreview> preview;
+  nsresult rv = GetTaskbarWindowPreview(shell, getter_AddRefs(preview));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return CallQueryInterface(preview, _retval);
+}
+
+NS_IMETHODIMP
+WinTaskbar::GetOverlayIconController(
+    nsIDocShell* shell, nsITaskbarOverlayIconController** _retval) {
+  nsCOMPtr<nsITaskbarWindowPreview> preview;
+  nsresult rv = GetTaskbarWindowPreview(shell, getter_AddRefs(preview));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return CallQueryInterface(preview, _retval);
+}
+
+NS_IMETHODIMP
+WinTaskbar::CreateLegacyJumpListBuilder(
+    bool aPrivateBrowsing, nsILegacyJumpListBuilder** aJumpListBuilder) {
+  nsresult rv;
+
+  if (LegacyJumpListBuilder::sBuildingList) return NS_ERROR_ALREADY_INITIALIZED;
+
+  nsCOMPtr<nsILegacyJumpListBuilder> builder =
+      do_CreateInstance(kLegacyJumpListBuilderCID, &rv);
+  if (NS_FAILED(rv)) return NS_ERROR_UNEXPECTED;
+
+  NS_IF_ADDREF(*aJumpListBuilder = builder);
+
+  nsAutoString aumid;
+  GenerateAppUserModelID(aumid, aPrivateBrowsing);
+  builder->SetAppUserModelID(aumid);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WinTaskbar::CreateJumpListBuilder(bool aPrivateBrowsing,
+                                  nsIJumpListBuilder** aJumpListBuilder) {
+  nsAutoString aumid;
+  GenerateAppUserModelID(aumid, aPrivateBrowsing);
+
+  nsCOMPtr<nsIJumpListBuilder> builder = new JumpListBuilder(aumid);
+  if (!builder) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  NS_IF_ADDREF(*aJumpListBuilder = builder);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WinTaskbar::GetGroupIdForWindow(mozIDOMWindow* aParent,
+                                nsAString& aIdentifier) {
+  NS_ENSURE_ARG_POINTER(aParent);
+  HWND toplevelHWND = ::GetAncestor(GetHWNDFromDOMWindow(aParent), GA_ROOT);
+  if (!toplevelHWND) return NS_ERROR_INVALID_ARG;
+  RefPtr<IPropertyStore> pPropStore;
+  if (FAILED(SHGetPropertyStoreForWindow(toplevelHWND, IID_IPropertyStore,
+                                         getter_AddRefs(pPropStore)))) {
+    return NS_ERROR_INVALID_ARG;
+  }
+  PROPVARIANT pv;
+  PropVariantInit(&pv);
+  auto cleanupPropVariant = MakeScopeExit([&] { PropVariantClear(&pv); });
+  if (FAILED(pPropStore->GetValue(PKEY_AppUserModel_ID, &pv))) {
+    return NS_ERROR_FAILURE;
+  }
+  if (pv.vt != VT_LPWSTR) {
+    // This can happen when there is no window specific group ID set
+    // It's not an error case so we have to check for empty strings
+    // returned from the function.
+    return NS_OK;
+  }
+  aIdentifier.Assign(char16ptr_t(pv.pwszVal));
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WinTaskbar::SetGroupIdForWindow(mozIDOMWindow* aParent,
+                                const nsAString& aIdentifier) {
+  return SetWindowAppUserModelProp(aParent, nsString(aIdentifier));
+}
+
+NS_IMETHODIMP
+WinTaskbar::PrepareFullScreen(void* aHWND, bool aFullScreen) {
+  if (!Initialize()) return NS_ERROR_NOT_AVAILABLE;
+
+  NS_ENSURE_ARG_POINTER(aHWND);
+
+  if (!::IsWindow((HWND)aHWND)) return NS_ERROR_INVALID_ARG;
+
+  HRESULT hr = mTaskbar->MarkFullscreenWindow((HWND)aHWND, aFullScreen);
+  if (FAILED(hr)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  return NS_OK;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/WinTaskbar.h b/widget/windows/WinTaskbar.h
new file mode 100644
index 0000000000..a6c483a561
--- /dev/null
+++ b/widget/windows/WinTaskbar.h
@@ -0,0 +1,46 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __WinTaskbar_h__
+#define __WinTaskbar_h__
+
+#include <windows.h>
+#include <shobjidl.h>
+#undef LogSeverity  // SetupAPI.h #defines this as DWORD
+#include "nsIWinTaskbar.h"
+#include "mozilla/Attributes.h"
+
+namespace mozilla {
+namespace widget {
+
+class WinTaskbar final : public nsIWinTaskbar {
+  ~WinTaskbar();
+
+ public:
+  WinTaskbar();
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIWINTASKBAR
+
+  static bool GenerateAppUserModelID(nsAString& aAppUserModelId,
+                                     bool aPrivateBrowsing = false);
+  // Registers the global app user model id for the instance.
+  // See comments in WinTaskbar.cpp for more information.
+  static bool RegisterAppUserModelID();
+  static bool GetAppUserModelID(nsAString& aDefaultGroupId,
+                                bool aPrivateBrowsing = false);
+
+ private:
+  bool Initialize();
+
+  ITaskbarList4* mTaskbar;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* __WinTaskbar_h__ */
diff --git a/widget/windows/WinTextEventDispatcherListener.cpp b/widget/windows/WinTextEventDispatcherListener.cpp
new file mode 100644
index 0000000000..aeed8be01b
--- /dev/null
+++ b/widget/windows/WinTextEventDispatcherListener.cpp
@@ -0,0 +1,68 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "KeyboardLayout.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/widget/IMEData.h"
+#include "nsWindow.h"
+#include "WinIMEHandler.h"
+#include "WinTextEventDispatcherListener.h"
+
+namespace mozilla {
+namespace widget {
+
+StaticRefPtr<WinTextEventDispatcherListener>
+    WinTextEventDispatcherListener::sInstance;
+
+// static
+WinTextEventDispatcherListener* WinTextEventDispatcherListener::GetInstance() {
+  if (!sInstance) {
+    sInstance = new WinTextEventDispatcherListener();
+  }
+  return sInstance.get();
+}
+
+void WinTextEventDispatcherListener::Shutdown() { sInstance = nullptr; }
+
+NS_IMPL_ISUPPORTS(WinTextEventDispatcherListener, TextEventDispatcherListener,
+                  nsISupportsWeakReference)
+
+WinTextEventDispatcherListener::WinTextEventDispatcherListener() {}
+
+WinTextEventDispatcherListener::~WinTextEventDispatcherListener() {}
+
+NS_IMETHODIMP
+WinTextEventDispatcherListener::NotifyIME(
+    TextEventDispatcher* aTextEventDispatcher,
+    const IMENotification& aNotification) {
+  nsWindow* window = static_cast<nsWindow*>(aTextEventDispatcher->GetWidget());
+  if (NS_WARN_IF(!window)) {
+    return NS_ERROR_FAILURE;
+  }
+  return IMEHandler::NotifyIME(window, aNotification);
+}
+
+NS_IMETHODIMP_(IMENotificationRequests)
+WinTextEventDispatcherListener::GetIMENotificationRequests() {
+  return IMEHandler::GetIMENotificationRequests();
+}
+
+NS_IMETHODIMP_(void)
+WinTextEventDispatcherListener::OnRemovedFrom(
+    TextEventDispatcher* aTextEventDispatcher) {
+  // XXX When input transaction is being stolen by add-on, what should we do?
+}
+
+NS_IMETHODIMP_(void)
+WinTextEventDispatcherListener::WillDispatchKeyboardEvent(
+    TextEventDispatcher* aTextEventDispatcher,
+    WidgetKeyboardEvent& aKeyboardEvent, uint32_t aIndexOfKeypress,
+    void* aData) {
+  static_cast<NativeKey*>(aData)->WillDispatchKeyboardEvent(aKeyboardEvent,
+                                                            aIndexOfKeypress);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/WinTextEventDispatcherListener.h b/widget/windows/WinTextEventDispatcherListener.h
new file mode 100644
index 0000000000..d799d0b280
--- /dev/null
+++ b/widget/windows/WinTextEventDispatcherListener.h
@@ -0,0 +1,50 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WinTextEventDispatcherListener_h_
+#define WinTextEventDispatcherListener_h_
+
+#include "mozilla/Attributes.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/TextEventDispatcherListener.h"
+
+namespace mozilla {
+namespace widget {
+
+/**
+ * On Windows, it's enough TextEventDispatcherListener to be a singleton
+ * because we have only one input context per process (IMM can create
+ * multiple IM context but we don't support such behavior).
+ */
+
+class WinTextEventDispatcherListener final
+    : public TextEventDispatcherListener {
+ public:
+  static WinTextEventDispatcherListener* GetInstance();
+  static void Shutdown();
+
+  NS_DECL_ISUPPORTS
+
+  NS_IMETHOD NotifyIME(TextEventDispatcher* aTextEventDispatcher,
+                       const IMENotification& aNotification) override;
+  NS_IMETHOD_(IMENotificationRequests) GetIMENotificationRequests() override;
+  NS_IMETHOD_(void)
+  OnRemovedFrom(TextEventDispatcher* aTextEventDispatcher) override;
+  NS_IMETHOD_(void)
+  WillDispatchKeyboardEvent(TextEventDispatcher* aTextEventDispatcher,
+                            WidgetKeyboardEvent& aKeyboardEvent,
+                            uint32_t aIndexOfKeypress, void* aData) override;
+
+ private:
+  WinTextEventDispatcherListener();
+  virtual ~WinTextEventDispatcherListener();
+
+  static StaticRefPtr<WinTextEventDispatcherListener> sInstance;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // #ifndef WinTextEventDispatcherListener_h_
diff --git a/widget/windows/WinUtils.cpp b/widget/windows/WinUtils.cpp
new file mode 100644
index 0000000000..1d8fad16f7
--- /dev/null
+++ b/widget/windows/WinUtils.cpp
@@ -0,0 +1,2107 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WinUtils.h"
+
+#include <knownfolders.h>
+#include <winioctl.h>
+
+#include "gfxPlatform.h"
+#include "gfxUtils.h"
+#include "nsWindow.h"
+#include "nsWindowDefs.h"
+#include "InputDeviceUtils.h"
+#include "KeyboardLayout.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/BackgroundHangMonitor.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/dom/MouseEventBinding.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/DataSurfaceHelpers.h"
+#include "mozilla/gfx/DisplayConfigWindows.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/ProfilerThreadSleep.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/SchedulerGroup.h"
+#include "mozilla/WinHeaderOnlyUtils.h"
+#include "mozilla/Unused.h"
+#include "nsIContentPolicy.h"
+#include "WindowsUIUtils.h"
+#include "nsContentUtils.h"
+
+#include "mozilla/Logging.h"
+
+#include "nsString.h"
+#include "nsDirectoryServiceUtils.h"
+#include "imgIContainer.h"
+#include "imgITools.h"
+#include "nsNetUtil.h"
+#include "nsIOutputStream.h"
+#include "nsNetCID.h"
+#include "prtime.h"
+#ifdef MOZ_PLACES
+#  include "nsIFaviconService.h"
+#endif
+#include "nsIDownloader.h"
+#include "nsIChannel.h"
+#include "nsIThread.h"
+#include "MainThreadUtils.h"
+#include "nsLookAndFeel.h"
+#include "nsUnicharUtils.h"
+#include "nsWindowsHelpers.h"
+#include "WinWindowOcclusionTracker.h"
+
+#include <textstor.h>
+#include "TSFTextStore.h"
+
+#include <shellscalingapi.h>
+#include <shlobj.h>
+#include <shlwapi.h>
+
+mozilla::LazyLogModule gWindowsLog("Widget");
+
+#define LOG_E(...) MOZ_LOG(gWindowsLog, LogLevel::Error, (__VA_ARGS__))
+#define LOG_D(...) MOZ_LOG(gWindowsLog, LogLevel::Debug, (__VA_ARGS__))
+
+using namespace mozilla::gfx;
+
+namespace mozilla {
+namespace widget {
+
+#ifdef MOZ_PLACES
+NS_IMPL_ISUPPORTS(myDownloadObserver, nsIDownloadObserver)
+NS_IMPL_ISUPPORTS(AsyncFaviconDataReady, nsIFaviconDataCallback)
+#endif
+NS_IMPL_ISUPPORTS(AsyncEncodeAndWriteIcon, nsIRunnable)
+NS_IMPL_ISUPPORTS(AsyncDeleteAllFaviconsFromDisk, nsIRunnable)
+
+const char FaviconHelper::kJumpListCacheDir[] = "jumpListCache";
+const char FaviconHelper::kShortcutCacheDir[] = "shortcutCache";
+
+struct CoTaskMemFreePolicy {
+  void operator()(void* aPtr) { ::CoTaskMemFree(aPtr); }
+};
+
+SetThreadDpiAwarenessContextProc WinUtils::sSetThreadDpiAwarenessContext = NULL;
+EnableNonClientDpiScalingProc WinUtils::sEnableNonClientDpiScaling = NULL;
+GetSystemMetricsForDpiProc WinUtils::sGetSystemMetricsForDpi = NULL;
+bool WinUtils::sHasPackageIdentity = false;
+
+using GetDpiForWindowProc = UINT(WINAPI*)(HWND);
+static GetDpiForWindowProc sGetDpiForWindow = NULL;
+
+/* static */
+void WinUtils::Initialize() {
+  // Dpi-Awareness is not supported with Win32k Lockdown enabled, so we don't
+  // initialize DPI-related members and assert later that nothing accidently
+  // uses these static members
+  if (!IsWin32kLockedDown()) {
+    HMODULE user32Dll = ::GetModuleHandleW(L"user32");
+    if (user32Dll) {
+      auto getThreadDpiAwarenessContext =
+          (decltype(GetThreadDpiAwarenessContext)*)::GetProcAddress(
+              user32Dll, "GetThreadDpiAwarenessContext");
+      auto areDpiAwarenessContextsEqual =
+          (decltype(AreDpiAwarenessContextsEqual)*)::GetProcAddress(
+              user32Dll, "AreDpiAwarenessContextsEqual");
+      if (getThreadDpiAwarenessContext && areDpiAwarenessContextsEqual &&
+          areDpiAwarenessContextsEqual(
+              getThreadDpiAwarenessContext(),
+              DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE)) {
+        // Only per-monitor v1 requires these workarounds.
+        sEnableNonClientDpiScaling =
+            (EnableNonClientDpiScalingProc)::GetProcAddress(
+                user32Dll, "EnableNonClientDpiScaling");
+        sSetThreadDpiAwarenessContext =
+            (SetThreadDpiAwarenessContextProc)::GetProcAddress(
+                user32Dll, "SetThreadDpiAwarenessContext");
+      }
+
+      sGetSystemMetricsForDpi = (GetSystemMetricsForDpiProc)::GetProcAddress(
+          user32Dll, "GetSystemMetricsForDpi");
+      sGetDpiForWindow =
+          (GetDpiForWindowProc)::GetProcAddress(user32Dll, "GetDpiForWindow");
+    }
+  }
+
+  sHasPackageIdentity = mozilla::HasPackageIdentity();
+}
+
+// static
+LRESULT WINAPI WinUtils::NonClientDpiScalingDefWindowProcW(HWND hWnd, UINT msg,
+                                                           WPARAM wParam,
+                                                           LPARAM lParam) {
+  MOZ_DIAGNOSTIC_ASSERT(!IsWin32kLockedDown());
+
+  // NOTE: this function was copied out into the body of the pre-XUL skeleton
+  // UI window proc (PreXULSkeletonUI.cpp). If this function changes at any
+  // point, we should probably factor this out and use it from both locations.
+  if (msg == WM_NCCREATE && sEnableNonClientDpiScaling) {
+    sEnableNonClientDpiScaling(hWnd);
+  }
+  return ::DefWindowProcW(hWnd, msg, wParam, lParam);
+}
+
+// static
+void WinUtils::LogW(const wchar_t* fmt, ...) {
+  va_list args = nullptr;
+  if (!lstrlenW(fmt)) {
+    return;
+  }
+  va_start(args, fmt);
+  int buflen = _vscwprintf(fmt, args);
+  wchar_t* buffer = new wchar_t[buflen + 1];
+  if (!buffer) {
+    va_end(args);
+    return;
+  }
+  vswprintf(buffer, buflen, fmt, args);
+  va_end(args);
+
+  // MSVC, including remote debug sessions
+  OutputDebugStringW(buffer);
+  OutputDebugStringW(L"\n");
+
+  int len =
+      WideCharToMultiByte(CP_ACP, 0, buffer, -1, nullptr, 0, nullptr, nullptr);
+  if (len) {
+    char* utf8 = new char[len];
+    if (WideCharToMultiByte(CP_ACP, 0, buffer, -1, utf8, len, nullptr,
+                            nullptr) > 0) {
+      // desktop console
+      printf("%s\n", utf8);
+      NS_ASSERTION(gWindowsLog,
+                   "Called WinUtils Log() but Widget "
+                   "log module doesn't exist!");
+      MOZ_LOG(gWindowsLog, LogLevel::Error, ("%s", utf8));
+    }
+    delete[] utf8;
+  }
+  delete[] buffer;
+}
+
+// static
+void WinUtils::Log(const char* fmt, ...) {
+  va_list args = nullptr;
+  if (!strlen(fmt)) {
+    return;
+  }
+  va_start(args, fmt);
+  int buflen = _vscprintf(fmt, args);
+  char* buffer = new char[buflen + 1];
+  if (!buffer) {
+    va_end(args);
+    return;
+  }
+  vsprintf(buffer, fmt, args);
+  va_end(args);
+
+  // MSVC, including remote debug sessions
+  OutputDebugStringA(buffer);
+  OutputDebugStringW(L"\n");
+
+  // desktop console
+  printf("%s\n", buffer);
+
+  NS_ASSERTION(gWindowsLog,
+               "Called WinUtils Log() but Widget "
+               "log module doesn't exist!");
+  MOZ_LOG(gWindowsLog, LogLevel::Error, ("%s", buffer));
+  delete[] buffer;
+}
+
+// static
+float WinUtils::SystemDPI() {
+  // The result of GetDeviceCaps won't change dynamically, as it predates
+  // per-monitor DPI and support for on-the-fly resolution changes.
+  // Therefore, we only need to look it up once.
+  static float dpi = 0;
+  if (dpi <= 0) {
+    HDC screenDC = GetDC(nullptr);
+    dpi = GetDeviceCaps(screenDC, LOGPIXELSY);
+    ReleaseDC(nullptr, screenDC);
+  }
+
+  // Bug 1012487 - dpi can be 0 when the Screen DC is used off the
+  // main thread on windows. For now just assume a 100% DPI for this
+  // drawing call.
+  // XXX - fixme!
+  return dpi > 0 ? dpi : 96;
+}
+
+// static
+double WinUtils::SystemScaleFactor() { return SystemDPI() / 96.0; }
+
+typedef HRESULT(WINAPI* GETDPIFORMONITORPROC)(HMONITOR, MONITOR_DPI_TYPE, UINT*,
+                                              UINT*);
+
+typedef HRESULT(WINAPI* GETPROCESSDPIAWARENESSPROC)(HANDLE,
+                                                    PROCESS_DPI_AWARENESS*);
+
+GETDPIFORMONITORPROC sGetDpiForMonitor;
+GETPROCESSDPIAWARENESSPROC sGetProcessDpiAwareness;
+
+static bool SlowIsPerMonitorDPIAware() {
+  // Intentionally leak the handle.
+  HMODULE shcore = LoadLibraryEx(L"shcore", NULL, LOAD_LIBRARY_SEARCH_SYSTEM32);
+  if (shcore) {
+    sGetDpiForMonitor =
+        (GETDPIFORMONITORPROC)GetProcAddress(shcore, "GetDpiForMonitor");
+    sGetProcessDpiAwareness = (GETPROCESSDPIAWARENESSPROC)GetProcAddress(
+        shcore, "GetProcessDpiAwareness");
+  }
+  PROCESS_DPI_AWARENESS dpiAwareness;
+  return sGetDpiForMonitor && sGetProcessDpiAwareness &&
+         SUCCEEDED(
+             sGetProcessDpiAwareness(GetCurrentProcess(), &dpiAwareness)) &&
+         dpiAwareness == PROCESS_PER_MONITOR_DPI_AWARE;
+}
+
+/* static */
+bool WinUtils::IsPerMonitorDPIAware() {
+  static bool perMonitorDPIAware = SlowIsPerMonitorDPIAware();
+  return perMonitorDPIAware;
+}
+
+/* static */
+float WinUtils::MonitorDPI(HMONITOR aMonitor) {
+  if (IsPerMonitorDPIAware()) {
+    UINT dpiX, dpiY = 96;
+    sGetDpiForMonitor(aMonitor ? aMonitor : GetPrimaryMonitor(),
+                      MDT_EFFECTIVE_DPI, &dpiX, &dpiY);
+    return dpiY;
+  }
+
+  // We're not per-monitor aware, use system DPI instead.
+  return SystemDPI();
+}
+
+/* static */
+double WinUtils::LogToPhysFactor(HMONITOR aMonitor) {
+  return MonitorDPI(aMonitor) / 96.0;
+}
+
+/* static */
+int32_t WinUtils::LogToPhys(HMONITOR aMonitor, double aValue) {
+  return int32_t(NS_round(aValue * LogToPhysFactor(aMonitor)));
+}
+
+/* static */
+double WinUtils::LogToPhysFactor(HWND aWnd) {
+  // if there's an ancestor window, we want to share its DPI setting
+  HWND ancestor = ::GetAncestor(aWnd, GA_ROOTOWNER);
+
+  // The GetDpiForWindow api is not available everywhere where we run as
+  // per-monitor, but if it is available rely on it to tell us the scale
+  // factor of the window.  See bug 1722085.
+  if (sGetDpiForWindow) {
+    UINT dpi = sGetDpiForWindow(ancestor ? ancestor : aWnd);
+    if (dpi > 0) {
+      return static_cast<double>(dpi) / 96.0;
+    }
+  }
+  return LogToPhysFactor(::MonitorFromWindow(ancestor ? ancestor : aWnd,
+                                             MONITOR_DEFAULTTOPRIMARY));
+}
+
+/* static */
+HMONITOR
+WinUtils::GetPrimaryMonitor() {
+  const POINT pt = {0, 0};
+  return ::MonitorFromPoint(pt, MONITOR_DEFAULTTOPRIMARY);
+}
+
+/* static */
+HMONITOR
+WinUtils::MonitorFromRect(const gfx::Rect& rect) {
+  // convert coordinates from desktop to device pixels for MonitorFromRect
+  double dpiScale =
+      IsPerMonitorDPIAware() ? 1.0 : LogToPhysFactor(GetPrimaryMonitor());
+
+  RECT globalWindowBounds = {NSToIntRound(dpiScale * rect.X()),
+                             NSToIntRound(dpiScale * rect.Y()),
+                             NSToIntRound(dpiScale * (rect.XMost())),
+                             NSToIntRound(dpiScale * (rect.YMost()))};
+
+  return ::MonitorFromRect(&globalWindowBounds, MONITOR_DEFAULTTONEAREST);
+}
+
+/* static */
+bool WinUtils::HasSystemMetricsForDpi() {
+  MOZ_DIAGNOSTIC_ASSERT(!IsWin32kLockedDown());
+  return (sGetSystemMetricsForDpi != NULL);
+}
+
+/* static */
+int WinUtils::GetSystemMetricsForDpi(int nIndex, UINT dpi) {
+  MOZ_DIAGNOSTIC_ASSERT(!IsWin32kLockedDown());
+  if (HasSystemMetricsForDpi()) {
+    return sGetSystemMetricsForDpi(nIndex, dpi);
+  } else {
+    double scale = IsPerMonitorDPIAware() ? dpi / SystemDPI() : 1.0;
+    return NSToIntRound(::GetSystemMetrics(nIndex) * scale);
+  }
+}
+
+/* static */
+gfx::MarginDouble WinUtils::GetUnwriteableMarginsForDeviceInInches(HDC aHdc) {
+  if (!aHdc) {
+    return gfx::MarginDouble();
+  }
+
+  int pixelsPerInchY = ::GetDeviceCaps(aHdc, LOGPIXELSY);
+  int marginTop = ::GetDeviceCaps(aHdc, PHYSICALOFFSETY);
+  int printableAreaHeight = ::GetDeviceCaps(aHdc, VERTRES);
+  int physicalHeight = ::GetDeviceCaps(aHdc, PHYSICALHEIGHT);
+
+  double marginTopInch = double(marginTop) / pixelsPerInchY;
+
+  double printableAreaHeightInch = double(printableAreaHeight) / pixelsPerInchY;
+  double physicalHeightInch = double(physicalHeight) / pixelsPerInchY;
+  double marginBottomInch =
+      physicalHeightInch - printableAreaHeightInch - marginTopInch;
+
+  int pixelsPerInchX = ::GetDeviceCaps(aHdc, LOGPIXELSX);
+  int marginLeft = ::GetDeviceCaps(aHdc, PHYSICALOFFSETX);
+  int printableAreaWidth = ::GetDeviceCaps(aHdc, HORZRES);
+  int physicalWidth = ::GetDeviceCaps(aHdc, PHYSICALWIDTH);
+
+  double marginLeftInch = double(marginLeft) / pixelsPerInchX;
+
+  double printableAreaWidthInch = double(printableAreaWidth) / pixelsPerInchX;
+  double physicalWidthInch = double(physicalWidth) / pixelsPerInchX;
+  double marginRightInch =
+      physicalWidthInch - printableAreaWidthInch - marginLeftInch;
+
+  return gfx::MarginDouble(marginTopInch, marginRightInch, marginBottomInch,
+                           marginLeftInch);
+}
+
+#ifdef ACCESSIBILITY
+/* static */
+a11y::LocalAccessible* WinUtils::GetRootAccessibleForHWND(HWND aHwnd) {
+  nsWindow* window = GetNSWindowPtr(aHwnd);
+  if (!window) {
+    return nullptr;
+  }
+
+  return window->GetAccessible();
+}
+#endif  // ACCESSIBILITY
+
+/* static */
+bool WinUtils::PeekMessage(LPMSG aMsg, HWND aWnd, UINT aFirstMessage,
+                           UINT aLastMessage, UINT aOption) {
+  RefPtr<ITfMessagePump> msgPump = TSFTextStore::GetMessagePump();
+  if (msgPump) {
+    BOOL ret = FALSE;
+    HRESULT hr = msgPump->PeekMessageW(aMsg, aWnd, aFirstMessage, aLastMessage,
+                                       aOption, &ret);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+    return ret;
+  }
+  return ::PeekMessageW(aMsg, aWnd, aFirstMessage, aLastMessage, aOption);
+}
+
+/* static */
+bool WinUtils::GetMessage(LPMSG aMsg, HWND aWnd, UINT aFirstMessage,
+                          UINT aLastMessage) {
+  RefPtr<ITfMessagePump> msgPump = TSFTextStore::GetMessagePump();
+  if (msgPump) {
+    BOOL ret = FALSE;
+    HRESULT hr =
+        msgPump->GetMessageW(aMsg, aWnd, aFirstMessage, aLastMessage, &ret);
+    NS_ENSURE_TRUE(SUCCEEDED(hr), false);
+    return ret;
+  }
+  return ::GetMessageW(aMsg, aWnd, aFirstMessage, aLastMessage);
+}
+
+#if defined(ACCESSIBILITY)
+static DWORD GetWaitFlags() {
+  DWORD result = MWMO_INPUTAVAILABLE;
+  if (XRE_IsContentProcess()) {
+    result |= MWMO_ALERTABLE;
+  }
+  return result;
+}
+#endif
+
+/* static */
+void WinUtils::WaitForMessage(DWORD aTimeoutMs) {
+#if defined(ACCESSIBILITY)
+  static const DWORD waitFlags = GetWaitFlags();
+#else
+  const DWORD waitFlags = MWMO_INPUTAVAILABLE;
+#endif
+
+  const DWORD waitStart = ::GetTickCount();
+  DWORD elapsed = 0;
+  while (true) {
+    if (aTimeoutMs != INFINITE) {
+      elapsed = ::GetTickCount() - waitStart;
+    }
+    if (elapsed >= aTimeoutMs) {
+      break;
+    }
+    DWORD result;
+    {
+      AUTO_PROFILER_THREAD_SLEEP;
+      result = ::MsgWaitForMultipleObjectsEx(0, NULL, aTimeoutMs - elapsed,
+                                             MOZ_QS_ALLEVENT, waitFlags);
+    }
+    NS_WARNING_ASSERTION(result != WAIT_FAILED, "Wait failed");
+    if (result == WAIT_TIMEOUT) {
+      break;
+    }
+#if defined(ACCESSIBILITY)
+    if (result == WAIT_IO_COMPLETION) {
+      if (NS_IsMainThread()) {
+        // We executed an APC that would have woken up the hang monitor. Since
+        // there are no more APCs pending and we are now going to sleep again,
+        // we should notify the hang monitor.
+        mozilla::BackgroundHangMonitor().NotifyWait();
+      }
+      continue;
+    }
+#endif  // defined(ACCESSIBILITY)
+
+    // Sent messages (via SendMessage and friends) are processed differently
+    // than queued messages (via PostMessage); the destination window procedure
+    // of the sent message is called during (Get|Peek)Message. Since PeekMessage
+    // does not tell us whether it processed any sent messages, we need to query
+    // this ahead of time.
+    bool haveSentMessagesPending =
+        (HIWORD(::GetQueueStatus(QS_SENDMESSAGE)) & QS_SENDMESSAGE) != 0;
+
+    MSG msg = {0};
+    if (haveSentMessagesPending ||
+        ::PeekMessageW(&msg, nullptr, 0, 0, PM_NOREMOVE)) {
+      break;
+    }
+    // The message is intended for another thread that has been synchronized
+    // with our input queue; yield to give other threads an opportunity to
+    // process the message. This should prevent busy waiting if resumed due
+    // to another thread's message.
+    ::SwitchToThread();
+  }
+}
+
+/* static */
+HWND WinUtils::GetTopLevelHWND(HWND aWnd, bool aStopIfNotChild,
+                               bool aStopIfNotPopup) {
+  HWND curWnd = aWnd;
+  HWND topWnd = nullptr;
+
+  while (curWnd) {
+    topWnd = curWnd;
+
+    if (aStopIfNotChild) {
+      DWORD_PTR style = ::GetWindowLongPtrW(curWnd, GWL_STYLE);
+
+      VERIFY_WINDOW_STYLE(style);
+
+      if (!(style & WS_CHILD))  // first top-level window
+        break;
+    }
+
+    HWND upWnd = ::GetParent(curWnd);  // Parent or owner (if has no parent)
+
+    // GetParent will only return the owner if the passed in window
+    // has the WS_POPUP style.
+    if (!upWnd && !aStopIfNotPopup) {
+      upWnd = ::GetWindow(curWnd, GW_OWNER);
+    }
+    curWnd = upWnd;
+  }
+
+  return topWnd;
+}
+
+// Map from native window handles to nsWindow structures. Does not AddRef.
+// Inherently unsafe to access outside the main thread.
+static nsTHashMap<HWND, nsWindow*> sExtantNSWindows;
+
+/* static */
+void WinUtils::SetNSWindowPtr(HWND aWnd, nsWindow* aWindow) {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (!aWindow) {
+    sExtantNSWindows.Remove(aWnd);
+  } else {
+    sExtantNSWindows.InsertOrUpdate(aWnd, aWindow);
+  }
+}
+
+/* static */
+nsWindow* WinUtils::GetNSWindowPtr(HWND aWnd) {
+  MOZ_ASSERT(NS_IsMainThread());
+  return sExtantNSWindows.Get(aWnd);  // or nullptr
+}
+
+/* static */
+bool WinUtils::IsOurProcessWindow(HWND aWnd) {
+  if (!aWnd) {
+    return false;
+  }
+  DWORD processId = 0;
+  ::GetWindowThreadProcessId(aWnd, &processId);
+  return (processId == ::GetCurrentProcessId());
+}
+
+/* static */
+HWND WinUtils::FindOurProcessWindow(HWND aWnd) {
+  for (HWND wnd = ::GetParent(aWnd); wnd; wnd = ::GetParent(wnd)) {
+    if (IsOurProcessWindow(wnd)) {
+      return wnd;
+    }
+  }
+  return nullptr;
+}
+
+static bool IsPointInWindow(HWND aWnd, const POINT& aPointInScreen) {
+  RECT bounds;
+  if (!::GetWindowRect(aWnd, &bounds)) {
+    return false;
+  }
+
+  return (aPointInScreen.x >= bounds.left && aPointInScreen.x < bounds.right &&
+          aPointInScreen.y >= bounds.top && aPointInScreen.y < bounds.bottom);
+}
+
+/**
+ * FindTopmostWindowAtPoint() returns the topmost child window (topmost means
+ * forground in this context) of aWnd.
+ */
+
+static HWND FindTopmostWindowAtPoint(HWND aWnd, const POINT& aPointInScreen) {
+  if (!::IsWindowVisible(aWnd) || !IsPointInWindow(aWnd, aPointInScreen)) {
+    return nullptr;
+  }
+
+  HWND childWnd = ::GetTopWindow(aWnd);
+  while (childWnd) {
+    HWND topmostWnd = FindTopmostWindowAtPoint(childWnd, aPointInScreen);
+    if (topmostWnd) {
+      return topmostWnd;
+    }
+    childWnd = ::GetNextWindow(childWnd, GW_HWNDNEXT);
+  }
+
+  return aWnd;
+}
+
+struct FindOurWindowAtPointInfo {
+  POINT mInPointInScreen;
+  HWND mOutWnd;
+};
+
+static BOOL CALLBACK FindOurWindowAtPointCallback(HWND aWnd, LPARAM aLPARAM) {
+  if (!WinUtils::IsOurProcessWindow(aWnd)) {
+    // This isn't one of our top-level windows; continue enumerating.
+    return TRUE;
+  }
+
+  // Get the top-most child window under the point.  If there's no child
+  // window, and the point is within the top-level window, then the top-level
+  // window will be returned.  (This is the usual case.  A child window
+  // would be returned for plugins.)
+  FindOurWindowAtPointInfo* info =
+      reinterpret_cast<FindOurWindowAtPointInfo*>(aLPARAM);
+  HWND childWnd = FindTopmostWindowAtPoint(aWnd, info->mInPointInScreen);
+  if (!childWnd) {
+    // This window doesn't contain the point; continue enumerating.
+    return TRUE;
+  }
+
+  // Return the HWND and stop enumerating.
+  info->mOutWnd = childWnd;
+  return FALSE;
+}
+
+/* static */
+HWND WinUtils::FindOurWindowAtPoint(const POINT& aPointInScreen) {
+  FindOurWindowAtPointInfo info;
+  info.mInPointInScreen = aPointInScreen;
+  info.mOutWnd = nullptr;
+
+  // This will enumerate all top-level windows in order from top to bottom.
+  EnumWindows(FindOurWindowAtPointCallback, reinterpret_cast<LPARAM>(&info));
+  return info.mOutWnd;
+}
+
+/* static */
+UINT WinUtils::GetInternalMessage(UINT aNativeMessage) {
+  switch (aNativeMessage) {
+    case WM_MOUSEWHEEL:
+      return MOZ_WM_MOUSEVWHEEL;
+    case WM_MOUSEHWHEEL:
+      return MOZ_WM_MOUSEHWHEEL;
+    case WM_VSCROLL:
+      return MOZ_WM_VSCROLL;
+    case WM_HSCROLL:
+      return MOZ_WM_HSCROLL;
+    default:
+      return aNativeMessage;
+  }
+}
+
+/* static */
+UINT WinUtils::GetNativeMessage(UINT aInternalMessage) {
+  switch (aInternalMessage) {
+    case MOZ_WM_MOUSEVWHEEL:
+      return WM_MOUSEWHEEL;
+    case MOZ_WM_MOUSEHWHEEL:
+      return WM_MOUSEHWHEEL;
+    case MOZ_WM_VSCROLL:
+      return WM_VSCROLL;
+    case MOZ_WM_HSCROLL:
+      return WM_HSCROLL;
+    default:
+      return aInternalMessage;
+  }
+}
+
+/* static */
+uint16_t WinUtils::GetMouseInputSource() {
+  int32_t inputSource = dom::MouseEvent_Binding::MOZ_SOURCE_MOUSE;
+  LPARAM lParamExtraInfo = ::GetMessageExtraInfo();
+  if ((lParamExtraInfo & TABLET_INK_SIGNATURE) == TABLET_INK_CHECK) {
+    inputSource = (lParamExtraInfo & TABLET_INK_TOUCH)
+                      ? dom::MouseEvent_Binding::MOZ_SOURCE_TOUCH
+                      : dom::MouseEvent_Binding::MOZ_SOURCE_PEN;
+  }
+  return static_cast<uint16_t>(inputSource);
+}
+
+/* static */
+uint16_t WinUtils::GetMousePointerID() {
+  LPARAM lParamExtraInfo = ::GetMessageExtraInfo();
+  return lParamExtraInfo & TABLET_INK_ID_MASK;
+}
+
+/* static */
+bool WinUtils::GetIsMouseFromTouch(EventMessage aEventMessage) {
+  const uint32_t MOZ_T_I_SIGNATURE = TABLET_INK_TOUCH | TABLET_INK_SIGNATURE;
+  const uint32_t MOZ_T_I_CHECK_TCH = TABLET_INK_TOUCH | TABLET_INK_CHECK;
+  return ((aEventMessage == eMouseMove || aEventMessage == eMouseDown ||
+           aEventMessage == eMouseUp || aEventMessage == eMouseAuxClick ||
+           aEventMessage == eMouseDoubleClick) &&
+          (GetMessageExtraInfo() & MOZ_T_I_SIGNATURE) == MOZ_T_I_CHECK_TCH);
+}
+
+/* static */
+MSG WinUtils::InitMSG(UINT aMessage, WPARAM wParam, LPARAM lParam, HWND aWnd) {
+  MSG msg;
+  msg.message = aMessage;
+  msg.wParam = wParam;
+  msg.lParam = lParam;
+  msg.hwnd = aWnd;
+  return msg;
+}
+
+#ifdef MOZ_PLACES
+/************************************************************************
+ * Constructs as AsyncFaviconDataReady Object
+ * @param aIOThread : the thread which performs the action
+ * @param aURLShortcut : Differentiates between (false)Jumplistcache and
+ *                       (true)Shortcutcache
+ * @param aRunnable : Executed in the aIOThread when the favicon cache is
+ *                    avaiable
+ ************************************************************************/
+
+AsyncFaviconDataReady::AsyncFaviconDataReady(
+    nsIURI* aNewURI, RefPtr<LazyIdleThread>& aIOThread, const bool aURLShortcut,
+    already_AddRefed<nsIRunnable> aRunnable)
+    : mNewURI(aNewURI),
+      mIOThread(aIOThread),
+      mRunnable(aRunnable),
+      mURLShortcut(aURLShortcut) {}
+
+NS_IMETHODIMP
+myDownloadObserver::OnDownloadComplete(nsIDownloader* downloader,
+                                       nsIRequest* request, nsresult status,
+                                       nsIFile* result) {
+  return NS_OK;
+}
+
+nsresult AsyncFaviconDataReady::OnFaviconDataNotAvailable(void) {
+  if (!mURLShortcut) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIFile> icoFile;
+  nsresult rv =
+      FaviconHelper::GetOutputIconPath(mNewURI, icoFile, mURLShortcut);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIURI> mozIconURI;
+  rv = NS_NewURI(getter_AddRefs(mozIconURI), "moz-icon://.html?size=32");
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  nsCOMPtr<nsIChannel> channel;
+  rv = NS_NewChannel(getter_AddRefs(channel), mozIconURI,
+                     nsContentUtils::GetSystemPrincipal(),
+                     nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
+                     nsIContentPolicy::TYPE_INTERNAL_IMAGE);
+
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIDownloadObserver> downloadObserver = new myDownloadObserver;
+  nsCOMPtr<nsIStreamListener> listener;
+  rv = NS_NewDownloader(getter_AddRefs(listener), downloadObserver, icoFile);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return channel->AsyncOpen(listener);
+}
+
+NS_IMETHODIMP
+AsyncFaviconDataReady::OnComplete(nsIURI* aFaviconURI, uint32_t aDataLen,
+                                  const uint8_t* aData,
+                                  const nsACString& aMimeType,
+                                  uint16_t aWidth) {
+  if (!aDataLen || !aData) {
+    if (mURLShortcut) {
+      OnFaviconDataNotAvailable();
+    }
+
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIFile> icoFile;
+  nsresult rv =
+      FaviconHelper::GetOutputIconPath(mNewURI, icoFile, mURLShortcut);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoString path;
+  rv = icoFile->GetPath(path);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Decode the image from the format it was returned to us in (probably PNG)
+  nsCOMPtr<imgIContainer> container;
+  nsCOMPtr<imgITools> imgtool = do_CreateInstance("@mozilla.org/image/tools;1");
+  rv = imgtool->DecodeImageFromBuffer(reinterpret_cast<const char*>(aData),
+                                      aDataLen, aMimeType,
+                                      getter_AddRefs(container));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  RefPtr<SourceSurface> surface = container->GetFrame(
+      imgIContainer::FRAME_FIRST,
+      imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
+  NS_ENSURE_TRUE(surface, NS_ERROR_FAILURE);
+
+  RefPtr<DataSourceSurface> dataSurface;
+  IntSize size;
+
+  if (mURLShortcut &&
+      (surface->GetSize().width < 48 || surface->GetSize().height < 48)) {
+    // Create a 48x48 surface and paint the icon into the central rect.
+    size.width = std::max(surface->GetSize().width, 48);
+    size.height = std::max(surface->GetSize().height, 48);
+    dataSurface =
+        Factory::CreateDataSourceSurface(size, SurfaceFormat::B8G8R8A8);
+    NS_ENSURE_TRUE(dataSurface, NS_ERROR_FAILURE);
+
+    DataSourceSurface::MappedSurface map;
+    if (!dataSurface->Map(DataSourceSurface::MapType::WRITE, &map)) {
+      return NS_ERROR_FAILURE;
+    }
+
+    RefPtr<DrawTarget> dt = Factory::CreateDrawTargetForData(
+        BackendType::CAIRO, map.mData, dataSurface->GetSize(), map.mStride,
+        dataSurface->GetFormat());
+    if (!dt) {
+      gfxWarning() << "AsyncFaviconDataReady::OnComplete failed in "
+                      "CreateDrawTargetForData";
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+    dt->FillRect(Rect(0, 0, size.width, size.height),
+                 ColorPattern(ToDeviceColor(sRGBColor::OpaqueWhite())));
+    IntPoint point;
+    point.x = (size.width - surface->GetSize().width) / 2;
+    point.y = (size.height - surface->GetSize().height) / 2;
+    dt->DrawSurface(surface,
+                    Rect(point.x, point.y, surface->GetSize().width,
+                         surface->GetSize().height),
+                    Rect(Point(0, 0), Size(surface->GetSize().width,
+                                           surface->GetSize().height)));
+
+    dataSurface->Unmap();
+  } else {
+    // By using the input image surface's size, we may end up encoding
+    // to a different size than a 16x16 (or bigger for higher DPI) ICO, but
+    // Windows will resize appropriately for us. If we want to encode ourselves
+    // one day because we like our resizing better, we'd have to manually
+    // resize the image here and use GetSystemMetrics w/ SM_CXSMICON and
+    // SM_CYSMICON. We don't support resizing images asynchronously at the
+    // moment anyway so getting the DPI aware icon size won't help.
+    size.width = surface->GetSize().width;
+    size.height = surface->GetSize().height;
+    dataSurface = surface->GetDataSurface();
+    NS_ENSURE_TRUE(dataSurface, NS_ERROR_FAILURE);
+  }
+
+  // Allocate a new buffer that we own and can use out of line in
+  // another thread.
+  UniquePtr<uint8_t[]> data = SurfaceToPackedBGRA(dataSurface);
+  if (!data) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  int32_t stride = 4 * size.width;
+
+  // AsyncEncodeAndWriteIcon takes ownership of the heap allocated buffer
+  nsCOMPtr<nsIRunnable> event =
+      new AsyncEncodeAndWriteIcon(path, std::move(data), stride, size.width,
+                                  size.height, mRunnable.forget());
+  mIOThread->Dispatch(event, NS_DISPATCH_NORMAL);
+
+  return NS_OK;
+}
+#endif
+
+// Warning: AsyncEncodeAndWriteIcon assumes ownership of the aData buffer passed
+// in
+AsyncEncodeAndWriteIcon::AsyncEncodeAndWriteIcon(
+    const nsAString& aIconPath, UniquePtr<uint8_t[]> aBuffer, uint32_t aStride,
+    uint32_t aWidth, uint32_t aHeight, already_AddRefed<nsIRunnable> aRunnable)
+    : mIconPath(aIconPath),
+      mBuffer(std::move(aBuffer)),
+      mRunnable(aRunnable),
+      mStride(aStride),
+      mWidth(aWidth),
+      mHeight(aHeight) {}
+
+NS_IMETHODIMP AsyncEncodeAndWriteIcon::Run() {
+  MOZ_ASSERT(!NS_IsMainThread(), "Should not be called on the main thread.");
+
+  // Note that since we're off the main thread we can't use
+  // gfxPlatform::GetPlatform()->ScreenReferenceDrawTarget()
+  RefPtr<DataSourceSurface> surface = Factory::CreateWrappingDataSourceSurface(
+      mBuffer.get(), mStride, IntSize(mWidth, mHeight),
+      SurfaceFormat::B8G8R8A8);
+
+  FILE* file = _wfopen(mIconPath.get(), L"wb");
+  if (!file) {
+    // Maybe the directory doesn't exist; try creating it, then fopen again.
+    nsresult rv = NS_ERROR_FAILURE;
+    nsCOMPtr<nsIFile> comFile = do_CreateInstance("@mozilla.org/file/local;1");
+    if (comFile) {
+      rv = comFile->InitWithPath(mIconPath);
+      if (NS_SUCCEEDED(rv)) {
+        nsCOMPtr<nsIFile> dirPath;
+        comFile->GetParent(getter_AddRefs(dirPath));
+        if (dirPath) {
+          rv = dirPath->Create(nsIFile::DIRECTORY_TYPE, 0777);
+          if (NS_SUCCEEDED(rv) || rv == NS_ERROR_FILE_ALREADY_EXISTS) {
+            file = _wfopen(mIconPath.get(), L"wb");
+            if (!file) {
+              rv = NS_ERROR_FAILURE;
+            }
+          }
+        }
+      }
+    }
+    if (!file) {
+      return rv;
+    }
+  }
+  nsresult rv = gfxUtils::EncodeSourceSurface(surface, ImageType::ICO, u""_ns,
+                                              gfxUtils::eBinaryEncode, file);
+  fclose(file);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (mRunnable) {
+    mRunnable->Run();
+  }
+  return rv;
+}
+
+AsyncEncodeAndWriteIcon::~AsyncEncodeAndWriteIcon() {}
+
+AsyncDeleteAllFaviconsFromDisk::AsyncDeleteAllFaviconsFromDisk(
+    bool aIgnoreRecent)
+    : mIgnoreRecent(aIgnoreRecent) {
+  // We can't call FaviconHelper::GetICOCacheSecondsTimeout() on non-main
+  // threads, as it reads a pref, so cache its value here.
+  mIcoNoDeleteSeconds = FaviconHelper::GetICOCacheSecondsTimeout() + 600;
+
+  // Prepare the profile directory cache on the main thread, to ensure we wont
+  // do this on non-main threads.
+  Unused << NS_GetSpecialDirectory("ProfLDS",
+                                   getter_AddRefs(mJumpListCacheDir));
+}
+
+NS_IMETHODIMP AsyncDeleteAllFaviconsFromDisk::Run() {
+  if (!mJumpListCacheDir) {
+    return NS_ERROR_FAILURE;
+  }
+  // Construct the path of our jump list cache
+  nsresult rv = mJumpListCacheDir->AppendNative(
+      nsDependentCString(FaviconHelper::kJumpListCacheDir));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIDirectoryEnumerator> entries;
+  rv = mJumpListCacheDir->GetDirectoryEntries(getter_AddRefs(entries));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Loop through each directory entry and remove all ICO files found
+  do {
+    nsCOMPtr<nsIFile> currFile;
+    if (NS_FAILED(entries->GetNextFile(getter_AddRefs(currFile))) || !currFile)
+      break;
+
+    nsAutoString path;
+    if (NS_FAILED(currFile->GetPath(path))) continue;
+
+    if (StringTail(path, 4).LowerCaseEqualsASCII(".ico")) {
+      // Check if the cached ICO file exists
+      bool exists;
+      if (NS_FAILED(currFile->Exists(&exists)) || !exists) continue;
+
+      if (mIgnoreRecent) {
+        // Check to make sure the icon wasn't just recently created.
+        // If it was created recently, don't delete it yet.
+        int64_t fileModTime = 0;
+        rv = currFile->GetLastModifiedTime(&fileModTime);
+        fileModTime /= PR_MSEC_PER_SEC;
+        // If the icon is older than the regeneration time (+ 10 min to be
+        // safe), then it's old and we can get rid of it.
+        // This code is only hit directly after a regeneration.
+        int64_t nowTime = PR_Now() / int64_t(PR_USEC_PER_SEC);
+        if (NS_FAILED(rv) || (nowTime - fileModTime) < mIcoNoDeleteSeconds) {
+          continue;
+        }
+      }
+
+      // We found an ICO file that exists, so we should remove it
+      currFile->Remove(false);
+    }
+  } while (true);
+
+  return NS_OK;
+}
+
+AsyncDeleteAllFaviconsFromDisk::~AsyncDeleteAllFaviconsFromDisk() {}
+
+/*
+ * (static) If the data is available, will return the path on disk where
+ * the favicon for page aFaviconPageURI is stored.  If the favicon does not
+ * exist, or its cache is expired, this method will kick off an async request
+ * for the icon so that next time the method is called it will be available.
+ * @param aFaviconPageURI The URI of the page to obtain
+ * @param aICOFilePath The path of the icon file
+ * @param aIOThread The thread to perform the Fetch on
+ * @param aURLShortcut to distinguish between jumplistcache(false) and
+ *                     shortcutcache(true)
+ * @param aRunnable Executed in the aIOThread when the favicon cache is
+ *                  avaiable
+ */
+nsresult FaviconHelper::ObtainCachedIconFile(
+    nsCOMPtr<nsIURI> aFaviconPageURI, nsString& aICOFilePath,
+    RefPtr<LazyIdleThread>& aIOThread, bool aURLShortcut,
+    already_AddRefed<nsIRunnable> aRunnable) {
+  nsCOMPtr<nsIRunnable> runnable = aRunnable;
+  // Obtain the ICO file path
+  nsCOMPtr<nsIFile> icoFile;
+  nsresult rv = GetOutputIconPath(aFaviconPageURI, icoFile, aURLShortcut);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Check if the cached ICO file already exists
+  bool exists;
+  rv = icoFile->Exists(&exists);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (exists) {
+    // Obtain the file's last modification date in seconds
+    int64_t fileModTime = 0;
+    rv = icoFile->GetLastModifiedTime(&fileModTime);
+    fileModTime /= PR_MSEC_PER_SEC;
+    int32_t icoReCacheSecondsTimeout = GetICOCacheSecondsTimeout();
+    int64_t nowTime = PR_Now() / int64_t(PR_USEC_PER_SEC);
+
+    // If the last mod call failed or the icon is old then re-cache it
+    // This check is in case the favicon of a page changes
+    // the next time we try to build the jump list, the data will be available.
+    if (NS_FAILED(rv) || (nowTime - fileModTime) > icoReCacheSecondsTimeout) {
+      CacheIconFileFromFaviconURIAsync(aFaviconPageURI, icoFile, aIOThread,
+                                       aURLShortcut, runnable.forget());
+      return NS_ERROR_NOT_AVAILABLE;
+    }
+  } else {
+    // The file does not exist yet, obtain it async from the favicon service so
+    // that the next time we try to build the jump list it'll be available.
+    CacheIconFileFromFaviconURIAsync(aFaviconPageURI, icoFile, aIOThread,
+                                     aURLShortcut, runnable.forget());
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  // The icoFile is filled with a path that exists, get its path
+  rv = icoFile->GetPath(aICOFilePath);
+  return rv;
+}
+
+// Hash a URI using a cryptographic hash function (currently SHA-256)
+// Output will be a base64-encoded string of the hash.
+static nsresult HashURI(nsIURI* aUri, nsACString& aUriHash) {
+  nsAutoCString spec;
+  nsresult rv = aUri->GetSpec(spec);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsICryptoHash> cryptoHash =
+      do_CreateInstance(NS_CRYPTO_HASH_CONTRACTID, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = cryptoHash->Init(nsICryptoHash::SHA256);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Add some context to the hash to even further reduce the chances of
+  // collision. Note that we are hashing this string with its null-terminator.
+  const char kHashUriContext[] = "firefox-uri";
+  rv = cryptoHash->Update(reinterpret_cast<const uint8_t*>(kHashUriContext),
+                          sizeof(kHashUriContext));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = cryptoHash->Update(reinterpret_cast<const uint8_t*>(spec.BeginReading()),
+                          spec.Length());
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = cryptoHash->Finish(true, aUriHash);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+// (static) Obtains the ICO file for the favicon at page aFaviconPageURI
+// If successful, the file path on disk is in the format:
+// <ProfLDS>\jumpListCache\<hash(aFaviconPageURI)>.ico
+//
+// We generate the name with a cryptographically secure hash function in order
+// to ensure that malicious websites can't intentionally craft URLs to collide
+// with legitimate websites.
+nsresult FaviconHelper::GetOutputIconPath(nsCOMPtr<nsIURI> aFaviconPageURI,
+                                          nsCOMPtr<nsIFile>& aICOFile,
+                                          bool aURLShortcut) {
+  nsAutoCString inputURIHash;
+  nsresult rv = HashURI(aFaviconPageURI, inputURIHash);
+  NS_ENSURE_SUCCESS(rv, rv);
+  char* cur = inputURIHash.BeginWriting();
+  char* end = inputURIHash.EndWriting();
+  for (; cur < end; ++cur) {
+    if ('/' == *cur) {
+      *cur = '_';
+    }
+  }
+
+  // Obtain the local profile directory and construct the output icon file path
+  rv = NS_GetSpecialDirectory("ProfLDS", getter_AddRefs(aICOFile));
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!aURLShortcut)
+    rv = aICOFile->AppendNative(nsDependentCString(kJumpListCacheDir));
+  else
+    rv = aICOFile->AppendNative(nsDependentCString(kShortcutCacheDir));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Append the icon extension
+  inputURIHash.AppendLiteral(".ico");
+  rv = aICOFile->AppendNative(inputURIHash);
+
+  return rv;
+}
+
+// (static) Asynchronously creates a cached ICO file on disk for the favicon of
+// page aFaviconPageURI and stores it to disk at the path of aICOFile.
+nsresult FaviconHelper::CacheIconFileFromFaviconURIAsync(
+    nsCOMPtr<nsIURI> aFaviconPageURI, nsCOMPtr<nsIFile> aICOFile,
+    RefPtr<LazyIdleThread>& aIOThread, bool aURLShortcut,
+    already_AddRefed<nsIRunnable> aRunnable) {
+  nsCOMPtr<nsIRunnable> runnable = aRunnable;
+#ifdef MOZ_PLACES
+  // Obtain the favicon service and get the favicon for the specified page
+  nsCOMPtr<nsIFaviconService> favIconSvc(
+      do_GetService("@mozilla.org/browser/favicon-service;1"));
+  NS_ENSURE_TRUE(favIconSvc, NS_ERROR_FAILURE);
+
+  nsCOMPtr<nsIFaviconDataCallback> callback =
+      new mozilla::widget::AsyncFaviconDataReady(
+          aFaviconPageURI, aIOThread, aURLShortcut, runnable.forget());
+
+  favIconSvc->GetFaviconDataForPage(aFaviconPageURI, callback, 0);
+#endif
+  return NS_OK;
+}
+
+// Obtains the jump list 'ICO cache timeout in seconds' pref
+int32_t FaviconHelper::GetICOCacheSecondsTimeout() {
+  // Only obtain the setting at most once from the pref service.
+  // In the rare case that 2 threads call this at the same
+  // time it is no harm and we will simply obtain the pref twice.
+  // None of the taskbar list prefs are currently updated via a
+  // pref observer so I think this should suffice.
+  const int32_t kSecondsPerDay = 86400;
+  static bool alreadyObtained = false;
+  static int32_t icoReCacheSecondsTimeout = kSecondsPerDay;
+  if (alreadyObtained) {
+    return icoReCacheSecondsTimeout;
+  }
+
+  // Obtain the pref
+  const char PREF_ICOTIMEOUT[] = "browser.taskbar.lists.icoTimeoutInSeconds";
+  icoReCacheSecondsTimeout =
+      Preferences::GetInt(PREF_ICOTIMEOUT, kSecondsPerDay);
+  alreadyObtained = true;
+  return icoReCacheSecondsTimeout;
+}
+
+/* static */
+LayoutDeviceIntRegion WinUtils::ConvertHRGNToRegion(HRGN aRgn) {
+  NS_ASSERTION(aRgn, "Don't pass NULL region here");
+
+  LayoutDeviceIntRegion rgn;
+
+  DWORD size = ::GetRegionData(aRgn, 0, nullptr);
+  AutoTArray<uint8_t, 100> buffer;
+  buffer.SetLength(size);
+
+  RGNDATA* data = reinterpret_cast<RGNDATA*>(buffer.Elements());
+  if (!::GetRegionData(aRgn, size, data)) return rgn;
+
+  if (data->rdh.nCount > MAX_RECTS_IN_REGION) {
+    rgn = ToIntRect(data->rdh.rcBound);
+    return rgn;
+  }
+
+  RECT* rects = reinterpret_cast<RECT*>(data->Buffer);
+  for (uint32_t i = 0; i < data->rdh.nCount; ++i) {
+    RECT* r = rects + i;
+    rgn.Or(rgn, ToIntRect(*r));
+  }
+
+  return rgn;
+}
+
+LayoutDeviceIntRect WinUtils::ToIntRect(const RECT& aRect) {
+  return LayoutDeviceIntRect(aRect.left, aRect.top, aRect.right - aRect.left,
+                             aRect.bottom - aRect.top);
+}
+
+/* static */
+bool WinUtils::IsIMEEnabled(const InputContext& aInputContext) {
+  return IsIMEEnabled(aInputContext.mIMEState.mEnabled);
+}
+
+/* static */
+bool WinUtils::IsIMEEnabled(IMEEnabled aIMEState) {
+  return aIMEState == IMEEnabled::Enabled;
+}
+
+/* static */
+void WinUtils::SetupKeyModifiersSequence(nsTArray<KeyPair>* aArray,
+                                         uint32_t aModifiers, UINT aMessage) {
+  MOZ_ASSERT(!(aModifiers & nsIWidget::ALTGRAPH) ||
+             !(aModifiers & (nsIWidget::CTRL_L | nsIWidget::ALT_R)));
+  if (aMessage == WM_KEYUP) {
+    // If AltGr is released, ControlLeft key is released first, then,
+    // AltRight key is released.
+    if (aModifiers & nsIWidget::ALTGRAPH) {
+      aArray->AppendElement(
+          KeyPair(VK_CONTROL, VK_LCONTROL, ScanCode::eControlLeft));
+      aArray->AppendElement(KeyPair(VK_MENU, VK_RMENU, ScanCode::eAltRight));
+    }
+    for (uint32_t i = ArrayLength(sModifierKeyMap); i; --i) {
+      const uint32_t* map = sModifierKeyMap[i - 1];
+      if (aModifiers & map[0]) {
+        aArray->AppendElement(KeyPair(map[1], map[2], map[3]));
+      }
+    }
+  } else {
+    for (uint32_t i = 0; i < ArrayLength(sModifierKeyMap); ++i) {
+      const uint32_t* map = sModifierKeyMap[i];
+      if (aModifiers & map[0]) {
+        aArray->AppendElement(KeyPair(map[1], map[2], map[3]));
+      }
+    }
+    // If AltGr is pressed, ControlLeft key is pressed first, then,
+    // AltRight key is pressed.
+    if (aModifiers & nsIWidget::ALTGRAPH) {
+      aArray->AppendElement(
+          KeyPair(VK_CONTROL, VK_LCONTROL, ScanCode::eControlLeft));
+      aArray->AppendElement(KeyPair(VK_MENU, VK_RMENU, ScanCode::eAltRight));
+    }
+  }
+}
+
+/* static */
+nsresult WinUtils::WriteBitmap(nsIFile* aFile, imgIContainer* aImage) {
+  RefPtr<SourceSurface> surface = aImage->GetFrame(
+      imgIContainer::FRAME_FIRST,
+      imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
+  NS_ENSURE_TRUE(surface, NS_ERROR_FAILURE);
+
+  return WriteBitmap(aFile, surface);
+}
+
+/* static */
+nsresult WinUtils::WriteBitmap(nsIFile* aFile, SourceSurface* surface) {
+  nsresult rv;
+
+  // For either of the following formats we want to set the biBitCount member
+  // of the BITMAPINFOHEADER struct to 32, below. For that value the bitmap
+  // format defines that the A8/X8 WORDs in the bitmap byte stream be ignored
+  // for the BI_RGB value we use for the biCompression member.
+  MOZ_ASSERT(surface->GetFormat() == SurfaceFormat::B8G8R8A8 ||
+             surface->GetFormat() == SurfaceFormat::B8G8R8X8);
+
+  RefPtr<DataSourceSurface> dataSurface = surface->GetDataSurface();
+  NS_ENSURE_TRUE(dataSurface, NS_ERROR_FAILURE);
+
+  int32_t width = dataSurface->GetSize().width;
+  int32_t height = dataSurface->GetSize().height;
+  int32_t bytesPerPixel = 4 * sizeof(uint8_t);
+  uint32_t bytesPerRow = bytesPerPixel * width;
+  bool hasAlpha = surface->GetFormat() == SurfaceFormat::B8G8R8A8;
+
+  // initialize these bitmap structs which we will later
+  // serialize directly to the head of the bitmap file
+  BITMAPV4HEADER bmi;
+  memset(&bmi, 0, sizeof(BITMAPV4HEADER));
+  bmi.bV4Size = sizeof(BITMAPV4HEADER);
+  bmi.bV4Width = width;
+  bmi.bV4Height = height;
+  bmi.bV4Planes = 1;
+  bmi.bV4BitCount = (WORD)bytesPerPixel * 8;
+  bmi.bV4V4Compression = hasAlpha ? BI_BITFIELDS : BI_RGB;
+  bmi.bV4SizeImage = bytesPerRow * height;
+  bmi.bV4CSType = LCS_sRGB;
+  if (hasAlpha) {
+    bmi.bV4RedMask = 0x00FF0000;
+    bmi.bV4GreenMask = 0x0000FF00;
+    bmi.bV4BlueMask = 0x000000FF;
+    bmi.bV4AlphaMask = 0xFF000000;
+  }
+
+  BITMAPFILEHEADER bf;
+  DWORD colormask[3];
+  bf.bfType = 0x4D42;  // 'BM'
+  bf.bfReserved1 = 0;
+  bf.bfReserved2 = 0;
+  bf.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPV4HEADER) +
+                 (hasAlpha ? sizeof(colormask) : 0);
+  bf.bfSize = bf.bfOffBits + bmi.bV4SizeImage;
+
+  // get a file output stream
+  nsCOMPtr<nsIOutputStream> stream;
+  rv = NS_NewLocalFileOutputStream(getter_AddRefs(stream), aFile);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  DataSourceSurface::MappedSurface map;
+  if (!dataSurface->Map(DataSourceSurface::MapType::READ, &map)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // write the bitmap headers and rgb pixel data to the file
+  rv = NS_ERROR_FAILURE;
+  if (stream) {
+    uint32_t written;
+    stream->Write((const char*)&bf, sizeof(BITMAPFILEHEADER), &written);
+    if (written == sizeof(BITMAPFILEHEADER)) {
+      stream->Write((const char*)&bmi, sizeof(BITMAPV4HEADER), &written);
+      if (written == sizeof(BITMAPV4HEADER)) {
+        if (hasAlpha) {
+          // color mask
+          colormask[0] = 0x00FF0000;
+          colormask[1] = 0x0000FF00;
+          colormask[2] = 0x000000FF;
+
+          stream->Write((const char*)colormask, sizeof(colormask), &written);
+        }
+        if (!hasAlpha || written == sizeof(colormask)) {
+          // write out the image data backwards because the desktop won't
+          // show bitmaps with negative heights for top-to-bottom
+          uint32_t i = map.mStride * height;
+          do {
+            i -= map.mStride;
+            stream->Write(((const char*)map.mData) + i, bytesPerRow, &written);
+            if (written == bytesPerRow) {
+              rv = NS_OK;
+            } else {
+              rv = NS_ERROR_FAILURE;
+              break;
+            }
+          } while (i != 0);
+        }
+      }
+    }
+
+    stream->Close();
+  }
+
+  dataSurface->Unmap();
+
+  return rv;
+}
+
+// This is in use here and in dom/events/TouchEvent.cpp
+/* static */
+uint32_t WinUtils::IsTouchDeviceSupportPresent() {
+  int32_t touchCapabilities = ::GetSystemMetrics(SM_DIGITIZER);
+  int32_t touchFlags = NID_EXTERNAL_TOUCH | NID_INTEGRATED_TOUCH;
+  if (StaticPrefs::dom_w3c_pointer_events_scroll_by_pen_enabled()) {
+    touchFlags |= NID_EXTERNAL_PEN | NID_INTEGRATED_PEN;
+  }
+  return (touchCapabilities & NID_READY) && (touchCapabilities & touchFlags);
+}
+
+/* static */
+uint32_t WinUtils::GetMaxTouchPoints() {
+  if (IsTouchDeviceSupportPresent()) {
+    return GetSystemMetrics(SM_MAXIMUMTOUCHES);
+  }
+  return 0;
+}
+
+/* static */
+POWER_PLATFORM_ROLE
+WinUtils::GetPowerPlatformRole() {
+  typedef POWER_PLATFORM_ROLE(WINAPI *
+                              PowerDeterminePlatformRoleEx)(ULONG Version);
+  static PowerDeterminePlatformRoleEx power_determine_platform_role =
+      reinterpret_cast<PowerDeterminePlatformRoleEx>(::GetProcAddress(
+          ::LoadLibraryW(L"PowrProf.dll"), "PowerDeterminePlatformRoleEx"));
+
+  POWER_PLATFORM_ROLE powerPlatformRole = PlatformRoleUnspecified;
+  if (!power_determine_platform_role) {
+    return powerPlatformRole;
+  }
+
+  return power_determine_platform_role(POWER_PLATFORM_ROLE_V2);
+}
+
+// static
+bool WinUtils::GetAutoRotationState(AR_STATE* aRotationState) {
+  typedef BOOL(WINAPI * GetAutoRotationStateFunc)(PAR_STATE pState);
+  static GetAutoRotationStateFunc get_auto_rotation_state_func =
+      reinterpret_cast<GetAutoRotationStateFunc>(::GetProcAddress(
+          GetModuleHandleW(L"user32.dll"), "GetAutoRotationState"));
+  if (get_auto_rotation_state_func) {
+    ZeroMemory(aRotationState, sizeof(AR_STATE));
+    return get_auto_rotation_state_func(aRotationState);
+  }
+  return false;
+}
+
+// static
+void WinUtils::GetClipboardFormatAsString(UINT aFormat, nsAString& aOutput) {
+  wchar_t buf[256] = {};
+  // Get registered format name and ensure the existence of a terminating '\0'
+  // if the registered name is more than 256 characters.
+  if (::GetClipboardFormatNameW(aFormat, buf, ARRAYSIZE(buf) - 1)) {
+    aOutput.Append(buf);
+    return;
+  }
+  // Standard clipboard formats
+  // https://learn.microsoft.com/en-us/windows/win32/dataxchg/standard-clipboard-formats
+  switch (aFormat) {
+    case CF_TEXT:  // 1
+      aOutput.Append(u"CF_TEXT"_ns);
+      break;
+    case CF_BITMAP:  // 2
+      aOutput.Append(u"CF_BITMAP"_ns);
+      break;
+    case CF_DIB:  // 8
+      aOutput.Append(u"CF_DIB"_ns);
+      break;
+    case CF_UNICODETEXT:  // 13
+      aOutput.Append(u"CF_UNICODETEXT"_ns);
+      break;
+    case CF_HDROP:  // 15
+      aOutput.Append(u"CF_HDROP"_ns);
+      break;
+    case CF_DIBV5:  // 17
+      aOutput.Append(u"CF_DIBV5"_ns);
+      break;
+    default:
+      aOutput.AppendPrintf("%u", aFormat);
+      break;
+  }
+}
+
+static bool IsTabletDevice() {
+  // Guarantees that:
+  // - The device has a touch screen.
+  // - It is used as a tablet which means that it has no keyboard connected.
+  // On Windows 10 it means that it is verifying with ConvertibleSlateMode.
+
+  if (WindowsUIUtils::GetInTabletMode()) {
+    return true;
+  }
+
+  if (!GetSystemMetrics(SM_MAXIMUMTOUCHES)) {
+    return false;
+  }
+
+  // If the device is docked, the user is treating the device as a PC.
+  if (GetSystemMetrics(SM_SYSTEMDOCKED)) {
+    return false;
+  }
+
+  // If the device is not supporting rotation, it's unlikely to be a tablet,
+  // a convertible or a detachable. See:
+  // https://msdn.microsoft.com/en-us/library/windows/desktop/dn629263(v=vs.85).aspx
+  AR_STATE rotation_state;
+  if (WinUtils::GetAutoRotationState(&rotation_state) &&
+      (rotation_state & (AR_NOT_SUPPORTED | AR_LAPTOP | AR_NOSENSOR))) {
+    return false;
+  }
+
+  // PlatformRoleSlate was added in Windows 8+.
+  POWER_PLATFORM_ROLE role = WinUtils::GetPowerPlatformRole();
+  if (role == PlatformRoleMobile || role == PlatformRoleSlate) {
+    return !GetSystemMetrics(SM_CONVERTIBLESLATEMODE);
+  }
+  return false;
+}
+
+static bool SystemHasMouse() {
+  // As per MSDN, this value is rarely false because of virtual mice, and
+  // some machines report the existance of a mouse port as a mouse.
+  //
+  // We probably could try to distinguish if we wanted, but a virtual mouse
+  // might be there for a reason, and maybe we shouldn't assume we know
+  // better.
+  return !!::GetSystemMetrics(SM_MOUSEPRESENT);
+}
+
+/* static */
+PointerCapabilities WinUtils::GetPrimaryPointerCapabilities() {
+  if (IsTabletDevice()) {
+    return PointerCapabilities::Coarse;
+  }
+
+  if (SystemHasMouse()) {
+    return PointerCapabilities::Fine | PointerCapabilities::Hover;
+  }
+
+  if (IsTouchDeviceSupportPresent()) {
+    return PointerCapabilities::Coarse;
+  }
+
+  return PointerCapabilities::None;
+}
+
+static bool SystemHasTouchscreen() {
+  int digitizerMetrics = ::GetSystemMetrics(SM_DIGITIZER);
+  return (digitizerMetrics & NID_INTEGRATED_TOUCH) ||
+         (digitizerMetrics & NID_EXTERNAL_TOUCH);
+}
+
+static bool SystemHasPenDigitizer() {
+  int digitizerMetrics = ::GetSystemMetrics(SM_DIGITIZER);
+  return (digitizerMetrics & NID_INTEGRATED_PEN) ||
+         (digitizerMetrics & NID_EXTERNAL_PEN);
+}
+
+/* static */
+PointerCapabilities WinUtils::GetAllPointerCapabilities() {
+  PointerCapabilities pointerCapabilities = PointerCapabilities::None;
+
+  if (SystemHasTouchscreen()) {
+    pointerCapabilities |= PointerCapabilities::Coarse;
+  }
+
+  if (SystemHasPenDigitizer() || SystemHasMouse()) {
+    pointerCapabilities |=
+        PointerCapabilities::Fine | PointerCapabilities::Hover;
+  }
+
+  return pointerCapabilities;
+}
+
+void WinUtils::GetPointerExplanation(nsAString* aExplanation) {
+  // To support localization, we will return a comma-separated list of
+  // Fluent IDs
+  *aExplanation = u"pointing-device-none";
+
+  bool first = true;
+  auto append = [&](const char16_t* str) {
+    if (first) {
+      aExplanation->Truncate();
+      first = false;
+    } else {
+      aExplanation->Append(u",");
+    }
+    aExplanation->Append(str);
+  };
+
+  if (SystemHasTouchscreen()) {
+    append(u"pointing-device-touchscreen");
+  }
+
+  if (SystemHasPenDigitizer()) {
+    append(u"pointing-device-pen-digitizer");
+  }
+
+  if (SystemHasMouse()) {
+    append(u"pointing-device-mouse");
+  }
+}
+
+/* static */
+bool WinUtils::ResolveJunctionPointsAndSymLinks(std::wstring& aPath) {
+  LOG_D("ResolveJunctionPointsAndSymLinks: Resolving path: %S", aPath.c_str());
+
+  wchar_t path[MAX_PATH] = {0};
+
+  nsAutoHandle handle(::CreateFileW(
+      aPath.c_str(), 0, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+      nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, nullptr));
+
+  if (handle == INVALID_HANDLE_VALUE) {
+    LOG_E("Failed to open file handle to resolve path. GetLastError=%lu",
+          GetLastError());
+    return false;
+  }
+
+  DWORD pathLen = GetFinalPathNameByHandleW(
+      handle, path, MAX_PATH, FILE_NAME_NORMALIZED | VOLUME_NAME_DOS);
+  if (pathLen == 0 || pathLen >= MAX_PATH) {
+    LOG_E("GetFinalPathNameByHandleW failed. GetLastError=%lu", GetLastError());
+    return false;
+  }
+  aPath = path;
+
+  // GetFinalPathNameByHandle sticks a '\\?\' in front of the path,
+  // but that confuses some APIs so strip it off. It will also put
+  // '\\?\UNC\' in front of network paths, we convert that to '\\'.
+  if (aPath.compare(0, 7, L"\\\\?\\UNC") == 0) {
+    aPath.erase(2, 6);
+  } else if (aPath.compare(0, 4, L"\\\\?\\") == 0) {
+    aPath.erase(0, 4);
+  }
+
+  LOG_D("ResolveJunctionPointsAndSymLinks: Resolved path to: %S",
+        aPath.c_str());
+  return true;
+}
+
+/* static */
+bool WinUtils::ResolveJunctionPointsAndSymLinks(nsIFile* aPath) {
+  MOZ_ASSERT(aPath);
+
+  nsAutoString filePath;
+  nsresult rv = aPath->GetPath(filePath);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+
+  std::wstring resolvedPath(filePath.get());
+  if (!ResolveJunctionPointsAndSymLinks(resolvedPath)) {
+    return false;
+  }
+
+  rv = aPath->InitWithPath(nsDependentString(resolvedPath.c_str()));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+
+  return true;
+}
+
+/* static */
+bool WinUtils::RunningFromANetworkDrive() {
+  wchar_t exePath[MAX_PATH];
+  if (!::GetModuleFileNameW(nullptr, exePath, MAX_PATH)) {
+    return false;
+  }
+
+  std::wstring exeString(exePath);
+  if (!widget::WinUtils::ResolveJunctionPointsAndSymLinks(exeString)) {
+    return false;
+  }
+
+  wchar_t volPath[MAX_PATH];
+  if (!::GetVolumePathNameW(exeString.c_str(), volPath, MAX_PATH)) {
+    return false;
+  }
+
+  return (::GetDriveTypeW(volPath) == DRIVE_REMOTE);
+}
+
+/* static */
+bool WinUtils::CanonicalizePath(nsAString& aPath) {
+  wchar_t tempPath[MAX_PATH + 1];
+  if (!PathCanonicalizeW(tempPath,
+                         (char16ptr_t)PromiseFlatString(aPath).get())) {
+    return false;
+  }
+  aPath = tempPath;
+  MOZ_ASSERT(aPath.Length() <= MAX_PATH);
+  return true;
+}
+
+/* static */
+bool WinUtils::MakeLongPath(nsAString& aPath) {
+  wchar_t tempPath[MAX_PATH + 1];
+  DWORD longResult =
+      GetLongPathNameW((char16ptr_t)PromiseFlatString(aPath).get(), tempPath,
+                       ArrayLength(tempPath));
+  if (longResult > ArrayLength(tempPath)) {
+    // Our buffer is too short, and we're guaranteeing <= MAX_PATH results.
+    return false;
+  } else if (longResult) {
+    // Success.
+    aPath = tempPath;
+    MOZ_ASSERT(aPath.Length() <= MAX_PATH);
+  }
+  // GetLongPathNameW returns 0 if the path is not found or is not rooted,
+  // but we shouldn't consider that a failure condition.
+  return true;
+}
+
+/* static */
+bool WinUtils::UnexpandEnvVars(nsAString& aPath) {
+  wchar_t tempPath[MAX_PATH + 1];
+  // PathUnExpandEnvStringsW returns false if it doesn't make any
+  // substitutions. Silently continue using the unaltered path.
+  if (PathUnExpandEnvStringsW((char16ptr_t)PromiseFlatString(aPath).get(),
+                              tempPath, ArrayLength(tempPath))) {
+    aPath = tempPath;
+    MOZ_ASSERT(aPath.Length() <= MAX_PATH);
+  }
+  return true;
+}
+
+/* static */
+WinUtils::WhitelistVec WinUtils::BuildWhitelist() {
+  WhitelistVec result;
+
+  Unused << result.emplaceBack(
+      std::make_pair(nsString(u"%ProgramFiles%"_ns), nsDependentString()));
+
+  // When no substitution is required, set the void flag
+  result.back().second.SetIsVoid(true);
+
+  Unused << result.emplaceBack(
+      std::make_pair(nsString(u"%SystemRoot%"_ns), nsDependentString()));
+  result.back().second.SetIsVoid(true);
+
+  wchar_t tmpPath[MAX_PATH + 1] = {};
+  if (GetTempPath(MAX_PATH, tmpPath)) {
+    // GetTempPath's result always ends with a backslash, which we don't want
+    uint32_t tmpPathLen = wcslen(tmpPath);
+    if (tmpPathLen) {
+      tmpPath[tmpPathLen - 1] = 0;
+    }
+
+    nsAutoString cleanTmpPath(tmpPath);
+    if (UnexpandEnvVars(cleanTmpPath)) {
+      constexpr auto tempVar = u"%TEMP%"_ns;
+      Unused << result.emplaceBack(std::make_pair(
+          nsString(cleanTmpPath), nsDependentString(tempVar, 0)));
+    }
+  }
+
+  // If we add more items to the whitelist, ensure we still don't invoke an
+  // unnecessary heap allocation.
+  MOZ_ASSERT(result.length() <= kMaxWhitelistedItems);
+
+  return result;
+}
+
+/**
+ * This function provides an array of (system path, substitution) pairs that are
+ * considered to be acceptable with respect to privacy, for the purposes of
+ * submitting within telemetry or crash reports.
+ *
+ * The substitution string's void flag may be set. If it is, no subsitution is
+ * necessary. Otherwise, the consumer should replace the system path with the
+ * substitution.
+ *
+ * @see PreparePathForTelemetry for an example of its usage.
+ */
+/* static */
+const WinUtils::WhitelistVec& WinUtils::GetWhitelistedPaths() {
+  static WhitelistVec sWhitelist([]() -> WhitelistVec {
+    auto setClearFn = [ptr = &sWhitelist]() -> void {
+      RunOnShutdown([ptr]() -> void { ptr->clear(); },
+                    ShutdownPhase::XPCOMShutdownFinal);
+    };
+
+    if (NS_IsMainThread()) {
+      setClearFn();
+    } else {
+      SchedulerGroup::Dispatch(NS_NewRunnableFunction(
+          "WinUtils::GetWhitelistedPaths", std::move(setClearFn)));
+    }
+
+    return BuildWhitelist();
+  }());
+  return sWhitelist;
+}
+
+/**
+ * This function is located here (as opposed to nsSystemInfo or elsewhere)
+ * because we need to gather this information as early as possible during
+ * startup.
+ */
+/* static */
+bool WinUtils::GetAppInitDLLs(nsAString& aOutput) {
+  aOutput.Truncate();
+  HKEY hkey = NULL;
+  if (RegOpenKeyExW(HKEY_LOCAL_MACHINE,
+                    L"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Windows",
+                    0, KEY_QUERY_VALUE, &hkey)) {
+    return false;
+  }
+  nsAutoRegKey key(hkey);
+  LONG status;
+  const wchar_t kLoadAppInitDLLs[] = L"LoadAppInit_DLLs";
+  DWORD loadAppInitDLLs = 0;
+  DWORD loadAppInitDLLsLen = sizeof(loadAppInitDLLs);
+  status = RegQueryValueExW(hkey, kLoadAppInitDLLs, nullptr, nullptr,
+                            (LPBYTE)&loadAppInitDLLs, &loadAppInitDLLsLen);
+  if (status != ERROR_SUCCESS) {
+    return false;
+  }
+  if (!loadAppInitDLLs) {
+    // If loadAppInitDLLs is zero then AppInit_DLLs is disabled.
+    // In this case we'll return true along with an empty output string.
+    return true;
+  }
+  DWORD numBytes = 0;
+  const wchar_t kAppInitDLLs[] = L"AppInit_DLLs";
+  // Query for required buffer size
+  status = RegQueryValueExW(hkey, kAppInitDLLs, nullptr, nullptr, nullptr,
+                            &numBytes);
+  if (status != ERROR_SUCCESS) {
+    return false;
+  }
+  // Allocate the buffer and query for the actual data
+  mozilla::UniquePtr<wchar_t[]> data =
+      mozilla::MakeUnique<wchar_t[]>(numBytes / sizeof(wchar_t));
+  status = RegQueryValueExW(hkey, kAppInitDLLs, nullptr, nullptr,
+                            (LPBYTE)data.get(), &numBytes);
+  if (status != ERROR_SUCCESS) {
+    return false;
+  }
+  // For each token, split up the filename components and then check the
+  // name of the file.
+  const wchar_t kDelimiters[] = L", ";
+  wchar_t* tokenContext = nullptr;
+  wchar_t* token = wcstok_s(data.get(), kDelimiters, &tokenContext);
+  while (token) {
+    nsAutoString cleanPath(token);
+    // Since these paths are short paths originating from the registry, we need
+    // to canonicalize them, lengthen them, and sanitize them before we can
+    // check them against the whitelist
+    if (PreparePathForTelemetry(cleanPath)) {
+      if (!aOutput.IsEmpty()) {
+        aOutput += L";";
+      }
+      aOutput += cleanPath;
+    }
+    token = wcstok_s(nullptr, kDelimiters, &tokenContext);
+  }
+  return true;
+}
+
+/* static */
+bool WinUtils::PreparePathForTelemetry(nsAString& aPath,
+                                       PathTransformFlags aFlags) {
+  if (aFlags & PathTransformFlags::Canonicalize) {
+    if (!CanonicalizePath(aPath)) {
+      return false;
+    }
+  }
+  if (aFlags & PathTransformFlags::Lengthen) {
+    if (!MakeLongPath(aPath)) {
+      return false;
+    }
+  }
+  if (aFlags & PathTransformFlags::UnexpandEnvVars) {
+    if (!UnexpandEnvVars(aPath)) {
+      return false;
+    }
+  }
+
+  const WhitelistVec& whitelistedPaths = GetWhitelistedPaths();
+
+  for (uint32_t i = 0; i < whitelistedPaths.length(); ++i) {
+    const nsString& testPath = whitelistedPaths[i].first;
+    const nsDependentString& substitution = whitelistedPaths[i].second;
+    if (StringBeginsWith(aPath, testPath, nsCaseInsensitiveStringComparator)) {
+      if (!substitution.IsVoid()) {
+        aPath.Replace(0, testPath.Length(), substitution);
+      }
+      return true;
+    }
+  }
+
+  // For non-whitelisted paths, we strip the path component and just leave
+  // the filename. We can't use nsLocalFile to do this because these paths may
+  // begin with environment variables, and nsLocalFile doesn't like
+  // non-absolute paths.
+  const nsString& flatPath = PromiseFlatString(aPath);
+  LPCWSTR leafStart = ::PathFindFileNameW(flatPath.get());
+  ptrdiff_t cutLen = leafStart - flatPath.get();
+  if (cutLen) {
+    aPath.Cut(0, cutLen);
+  } else if (aFlags & PathTransformFlags::RequireFilePath) {
+    return false;
+  }
+
+  return true;
+}
+
+nsString WinUtils::GetPackageFamilyName() {
+  nsString rv;
+
+  UniquePtr<wchar_t[]> packageIdentity = mozilla::GetPackageFamilyName();
+  if (packageIdentity) {
+    rv = packageIdentity.get();
+  }
+
+  return rv;
+}
+
+bool WinUtils::GetClassName(HWND aHwnd, nsAString& aClassName) {
+  const int bufferLength = 256;
+  aClassName.SetLength(bufferLength);
+
+  int length = ::GetClassNameW(aHwnd, (char16ptr_t)aClassName.BeginWriting(),
+                               bufferLength);
+  if (length == 0) {
+    return false;
+  }
+  MOZ_RELEASE_ASSERT(length <= (bufferLength - 1));
+  aClassName.Truncate(length);
+  return true;
+}
+
+static BOOL CALLBACK EnumUpdateWindowOcclusionProc(HWND aHwnd, LPARAM aLParam) {
+  const bool* const enable = reinterpret_cast<bool*>(aLParam);
+  nsWindow* window = WinUtils::GetNSWindowPtr(aHwnd);
+  if (window) {
+    window->MaybeEnableWindowOcclusion(*enable);
+  }
+  return TRUE;
+}
+
+void WinUtils::EnableWindowOcclusion(const bool aEnable) {
+  if (aEnable) {
+    WinWindowOcclusionTracker::Ensure();
+  }
+  ::EnumWindows(EnumUpdateWindowOcclusionProc,
+                reinterpret_cast<LPARAM>(&aEnable));
+}
+
+bool WinUtils::GetTimezoneName(wchar_t* aBuffer) {
+  DYNAMIC_TIME_ZONE_INFORMATION tzInfo;
+  DWORD tzid = GetDynamicTimeZoneInformation(&tzInfo);
+
+  if (tzid == TIME_ZONE_ID_INVALID) {
+    return false;
+  }
+
+  wcscpy_s(aBuffer, 128, tzInfo.TimeZoneKeyName);
+
+  return true;
+}
+
+// There are undocumented APIs to query/change the system DPI settings found by
+// https://github.com/lihas/ . We use those APIs only for testing purpose, i.e.
+// in mochitests or some such. To avoid exposing them in our official release
+// builds unexpectedly we restrict them only in debug builds.
+#ifdef DEBUG
+
+#  define DISPLAYCONFIG_DEVICE_INFO_SET_SOURCE_DPI_SCALE (int)-4
+#  define DISPLAYCONFIG_DEVICE_INFO_GET_SOURCE_DPI_SCALE (int)-3
+
+// Following two struts are copied from
+// https://github.com/lihas/windows-DPI-scaling-sample/blob/master/DPIHelper/DpiHelper.h
+
+/*
+ * struct DISPLAYCONFIG_SOURCE_DPI_SCALE_GET
+ * @brief used to fetch min, max, suggested, and currently applied DPI scaling
+ * values. All values are relative to the recommended DPI scaling value Note
+ * that DPI scaling is a property of the source, and not of target.
+ */
+struct DISPLAYCONFIG_SOURCE_DPI_SCALE_GET {
+  DISPLAYCONFIG_DEVICE_INFO_HEADER header;
+  /*
+   * @brief min value of DPI scaling is always 100, minScaleRel gives no. of
+   * steps down from recommended scaling eg. if minScaleRel is -3 => 100 is 3
+   * steps down from recommended scaling => recommended scaling is 175%
+   */
+  int32_t minScaleRel;
+
+  /*
+   * @brief currently applied DPI scaling value wrt the recommended value. eg.
+   * if recommended value is 175%,
+   * => if curScaleRel == 0 the current scaling is 175%, if curScaleRel == -1,
+   * then current scale is 150%
+   */
+  int32_t curScaleRel;
+
+  /*
+   * @brief maximum supported DPI scaling wrt recommended value
+   */
+  int32_t maxScaleRel;
+};
+
+/*
+ * struct DISPLAYCONFIG_SOURCE_DPI_SCALE_SET
+ * @brief set DPI scaling value of a source
+ * Note that DPI scaling is a property of the source, and not of target.
+ */
+struct DISPLAYCONFIG_SOURCE_DPI_SCALE_SET {
+  DISPLAYCONFIG_DEVICE_INFO_HEADER header;
+  /*
+   * @brief The value we want to set. The value should be relative to the
+   * recommended DPI scaling value of source. eg. if scaleRel == 1, and
+   * recommended value is 175% => we are trying to set 200% scaling for the
+   * source
+   */
+  int32_t scaleRel;
+};
+
+static int32_t sCurRelativeScaleStep = std::numeric_limits<int32_t>::max();
+
+static LONG SetRelativeScaleStep(LUID aAdapterId, int32_t aRelativeScaleStep) {
+  DISPLAYCONFIG_SOURCE_DPI_SCALE_SET setDPIScale = {};
+  setDPIScale.header.adapterId = aAdapterId;
+  setDPIScale.header.type = (DISPLAYCONFIG_DEVICE_INFO_TYPE)
+      DISPLAYCONFIG_DEVICE_INFO_SET_SOURCE_DPI_SCALE;
+  setDPIScale.header.size = sizeof(setDPIScale);
+  setDPIScale.scaleRel = aRelativeScaleStep;
+
+  return DisplayConfigSetDeviceInfo(&setDPIScale.header);
+}
+
+nsresult WinUtils::SetHiDPIMode(bool aHiDPI) {
+  auto config = GetDisplayConfig();
+  if (!config) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  if (config->mPaths.empty()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  DISPLAYCONFIG_SOURCE_DPI_SCALE_GET dpiScale = {};
+  dpiScale.header.adapterId = config->mPaths[0].targetInfo.adapterId;
+  dpiScale.header.type = (DISPLAYCONFIG_DEVICE_INFO_TYPE)
+      DISPLAYCONFIG_DEVICE_INFO_GET_SOURCE_DPI_SCALE;
+  dpiScale.header.size = sizeof(dpiScale);
+  LONG result = ::DisplayConfigGetDeviceInfo(&dpiScale.header);
+  if (result != ERROR_SUCCESS) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (dpiScale.minScaleRel == dpiScale.maxScaleRel) {
+    // We can't change the setting at all.
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  if (aHiDPI && dpiScale.curScaleRel == dpiScale.maxScaleRel) {
+    // We've already at the maximum level.
+    if (sCurRelativeScaleStep == std::numeric_limits<int32_t>::max()) {
+      sCurRelativeScaleStep = dpiScale.curScaleRel;
+    }
+    return NS_OK;
+  }
+
+  if (!aHiDPI && dpiScale.curScaleRel == dpiScale.minScaleRel) {
+    // We've already at the minimum level.
+    if (sCurRelativeScaleStep == std::numeric_limits<int32_t>::max()) {
+      sCurRelativeScaleStep = dpiScale.curScaleRel;
+    }
+    return NS_OK;
+  }
+
+  result = SetRelativeScaleStep(
+      config->mPaths[0].targetInfo.adapterId,
+      aHiDPI ? dpiScale.maxScaleRel : dpiScale.minScaleRel);
+  if (result != ERROR_SUCCESS) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (sCurRelativeScaleStep == std::numeric_limits<int>::max()) {
+    sCurRelativeScaleStep = dpiScale.curScaleRel;
+  }
+
+  return NS_OK;
+}
+
+nsresult WinUtils::RestoreHiDPIMode() {
+  if (sCurRelativeScaleStep == std::numeric_limits<int>::max()) {
+    // The DPI setting hasn't been changed.
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  auto config = GetDisplayConfig();
+  if (!config) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  if (config->mPaths.empty()) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  LONG result = SetRelativeScaleStep(config->mPaths[0].targetInfo.adapterId,
+                                     sCurRelativeScaleStep);
+  sCurRelativeScaleStep = std::numeric_limits<int32_t>::max();
+  if (result != ERROR_SUCCESS) {
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+#endif
+
+/* static */
+const char* WinUtils::WinEventToEventName(UINT msg) {
+  const auto eventMsgInfo = mozilla::widget::gAllEvents.find(msg);
+  return eventMsgInfo != mozilla::widget::gAllEvents.end()
+             ? eventMsgInfo->second.mStr
+             : nullptr;
+}
+
+// Note to testers and/or test-authors: on Windows 10, and possibly on other
+// versions as well, supplying the `WS_EX_LAYOUTRTL` flag here has no effect
+// whatsoever on child common-dialogs **unless the system UI locale is also set
+// to an RTL language**.
+//
+// If it is, the flag is still required; otherwise, the picker dialog will be
+// presented in English (or possibly some other LTR language) as a fallback.
+ScopedRtlShimWindow::ScopedRtlShimWindow(nsIWidget* aParent) : mWnd(nullptr) {
+  NS_ENSURE_TRUE_VOID(aParent);
+
+  // Headless windows don't have HWNDs, but also probably shouldn't be launching
+  // print dialogs.
+  HWND const hwnd = (HWND)aParent->GetNativeData(NS_NATIVE_WINDOW);
+  NS_ENSURE_TRUE_VOID(hwnd);
+
+  nsWindow* const win = WinUtils::GetNSWindowPtr(hwnd);
+  NS_ENSURE_TRUE_VOID(win);
+
+  ATOM const wclass = ::GetClassWord(hwnd, GCW_ATOM);
+  mWnd = ::CreateWindowExW(
+      win->IsRTL() ? WS_EX_LAYOUTRTL : 0, (LPCWSTR)(uintptr_t)wclass, L"",
+      WS_CHILD, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
+      hwnd, nullptr, nsToolkit::mDllInstance, nullptr);
+
+  MOZ_ASSERT(mWnd);
+}
+
+ScopedRtlShimWindow::~ScopedRtlShimWindow() {
+  if (mWnd) {
+    ::DestroyWindow(mWnd);
+  }
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/WinUtils.h b/widget/windows/WinUtils.h
new file mode 100644
index 0000000000..daef5ff4bc
--- /dev/null
+++ b/widget/windows/WinUtils.h
@@ -0,0 +1,684 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_WinUtils_h__
+#define mozilla_widget_WinUtils_h__
+
+#include "nscore.h"
+#include <windows.h>
+#include <shobjidl.h>
+#include <uxtheme.h>
+#include <dwmapi.h>
+#include <unordered_map>
+#include <utility>
+
+// Undo the windows.h damage
+#undef GetMessage
+#undef CreateEvent
+#undef GetClassName
+#undef GetBinaryType
+#undef RemoveDirectory
+
+#include "nsString.h"
+#include "nsRegion.h"
+#include "nsRect.h"
+
+#include "nsIRunnable.h"
+#include "nsICryptoHash.h"
+#ifdef MOZ_PLACES
+#  include "nsIFaviconService.h"
+#endif
+#include "nsIDownloader.h"
+#include "nsIURI.h"
+#include "nsIWidget.h"
+#include "nsIThread.h"
+
+#include "mozilla/Attributes.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/HalScreenConfiguration.h"
+#include "mozilla/HashTable.h"
+#include "mozilla/LazyIdleThread.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Vector.h"
+#include "mozilla/WindowsDpiAwareness.h"
+#include "mozilla/WindowsProcessMitigations.h"
+#include "mozilla/gfx/2D.h"
+
+/**
+ * NS_INLINE_DECL_IUNKNOWN_REFCOUNTING should be used for defining and
+ * implementing AddRef() and Release() of IUnknown interface.
+ * This depends on xpcom/base/nsISupportsImpl.h.
+ */
+
+#define NS_INLINE_DECL_IUNKNOWN_REFCOUNTING(_class)                         \
+ public:                                                                    \
+  STDMETHODIMP_(ULONG) AddRef() {                                           \
+    MOZ_ASSERT_TYPE_OK_FOR_REFCOUNTING(_class)                              \
+    MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt");                    \
+    NS_ASSERT_OWNINGTHREAD(_class);                                         \
+    ++mRefCnt;                                                              \
+    NS_LOG_ADDREF(this, mRefCnt, #_class, sizeof(*this));                   \
+    return static_cast<ULONG>(mRefCnt.get());                               \
+  }                                                                         \
+  STDMETHODIMP_(ULONG) Release() {                                          \
+    MOZ_ASSERT(int32_t(mRefCnt) > 0,                                        \
+               "Release called on object that has already been released!"); \
+    NS_ASSERT_OWNINGTHREAD(_class);                                         \
+    --mRefCnt;                                                              \
+    NS_LOG_RELEASE(this, mRefCnt, #_class);                                 \
+    if (mRefCnt == 0) {                                                     \
+      NS_ASSERT_OWNINGTHREAD(_class);                                       \
+      mRefCnt = 1; /* stabilize */                                          \
+      delete this;                                                          \
+      return 0;                                                             \
+    }                                                                       \
+    return static_cast<ULONG>(mRefCnt.get());                               \
+  }                                                                         \
+                                                                            \
+ protected:                                                                 \
+  nsAutoRefCnt mRefCnt;                                                     \
+  NS_DECL_OWNINGTHREAD                                                      \
+ public:
+
+class nsWindow;
+struct KeyPair;
+
+namespace mozilla {
+enum class PointerCapabilities : uint8_t;
+#if defined(ACCESSIBILITY)
+namespace a11y {
+class LocalAccessible;
+}  // namespace a11y
+#endif  // defined(ACCESSIBILITY)
+
+// Helper function: enumerate all the toplevel HWNDs attached to the current
+// thread via ::EnumThreadWindows().
+//
+// Note that this use of ::EnumThreadWindows() is, unfortunately, not an
+// abstract implementation detail.
+template <typename F>
+void EnumerateThreadWindows(F&& f)
+// requires requires(F f, HWND h) { f(h); }
+{
+  class Impl {
+   public:
+    F f;
+    explicit Impl(F&& f) : f(std::forward<F>(f)) {}
+
+    void invoke() {
+      WNDENUMPROC proc = &Impl::Callback;
+      ::EnumThreadWindows(::GetCurrentThreadId(), proc,
+                          reinterpret_cast<LPARAM>(&f));
+    }
+
+   private:
+    static BOOL CALLBACK Callback(HWND hwnd, LPARAM lp) {
+      (*reinterpret_cast<F*>(lp))(hwnd);
+      return TRUE;
+    }
+  };
+
+  Impl(std::forward<F>(f)).invoke();
+}
+
+namespace widget {
+
+// More complete QS definitions for MsgWaitForMultipleObjects() and
+// GetQueueStatus() that include newer win8 specific defines.
+
+#ifndef QS_RAWINPUT
+#  define QS_RAWINPUT 0x0400
+#endif
+
+#ifndef QS_TOUCH
+#  define QS_TOUCH 0x0800
+#  define QS_POINTER 0x1000
+#endif
+
+#define MOZ_QS_ALLEVENT                                                      \
+  (QS_KEY | QS_MOUSEMOVE | QS_MOUSEBUTTON | QS_POSTMESSAGE | QS_TIMER |      \
+   QS_PAINT | QS_SENDMESSAGE | QS_HOTKEY | QS_ALLPOSTMESSAGE | QS_RAWINPUT | \
+   QS_TOUCH | QS_POINTER)
+
+// Logging macros
+#define LogFunction() mozilla::widget::WinUtils::Log(__FUNCTION__)
+#define LogThread()                                                 \
+  mozilla::widget::WinUtils::Log("%s: IsMainThread:%d ThreadId:%X", \
+                                 __FUNCTION__, NS_IsMainThread(),   \
+                                 GetCurrentThreadId())
+#define LogThis() mozilla::widget::WinUtils::Log("[%X] %s", this, __FUNCTION__)
+#define LogException(e)                                           \
+  mozilla::widget::WinUtils::Log("%s Exception:%s", __FUNCTION__, \
+                                 e->ToString()->Data())
+#define LogHRESULT(hr) \
+  mozilla::widget::WinUtils::Log("%s hr=%X", __FUNCTION__, hr)
+
+#ifdef MOZ_PLACES
+class myDownloadObserver final : public nsIDownloadObserver {
+  ~myDownloadObserver() {}
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIDOWNLOADOBSERVER
+};
+#endif
+
+class WinUtils {
+  // Function pointers for APIs that may not be available depending on
+  // the Win10 update version -- will be set up in Initialize().
+  static SetThreadDpiAwarenessContextProc sSetThreadDpiAwarenessContext;
+  static EnableNonClientDpiScalingProc sEnableNonClientDpiScaling;
+  static GetSystemMetricsForDpiProc sGetSystemMetricsForDpi;
+
+  // Set on Initialize().
+  static bool sHasPackageIdentity;
+
+ public:
+  class AutoSystemDpiAware {
+   public:
+    AutoSystemDpiAware() {
+      MOZ_DIAGNOSTIC_ASSERT(!IsWin32kLockedDown());
+
+      if (sSetThreadDpiAwarenessContext) {
+        mPrevContext =
+            sSetThreadDpiAwarenessContext(DPI_AWARENESS_CONTEXT_SYSTEM_AWARE);
+      }
+    }
+
+    ~AutoSystemDpiAware() {
+      if (sSetThreadDpiAwarenessContext) {
+        sSetThreadDpiAwarenessContext(mPrevContext);
+      }
+    }
+
+   private:
+    DPI_AWARENESS_CONTEXT mPrevContext;
+  };
+
+  // Wrapper for DefWindowProc that will enable non-client dpi scaling on the
+  // window during creation.
+  static LRESULT WINAPI NonClientDpiScalingDefWindowProcW(HWND hWnd, UINT msg,
+                                                          WPARAM wParam,
+                                                          LPARAM lParam);
+
+  /**
+   * Get the system's default logical-to-physical DPI scaling factor,
+   * which is based on the primary display. Note however that unlike
+   * LogToPhysFactor(GetPrimaryMonitor()), this will not change during
+   * a session even if the displays are reconfigured. This scale factor
+   * is used by Windows theme metrics etc, which do not fully support
+   * dynamic resolution changes but are only updated on logout.
+   */
+  static double SystemScaleFactor();
+
+  static bool IsPerMonitorDPIAware();
+  /**
+   * Get the DPI of the given monitor if it's per-monitor DPI aware, otherwise
+   * return the system DPI.
+   */
+  static float MonitorDPI(HMONITOR aMonitor);
+  static float SystemDPI();
+  /**
+   * Functions to convert between logical pixels as used by most Windows APIs
+   * and physical (device) pixels.
+   */
+  static double LogToPhysFactor(HMONITOR aMonitor);
+  static double LogToPhysFactor(HWND aWnd);
+  static double LogToPhysFactor(HDC aDC) {
+    return LogToPhysFactor(::WindowFromDC(aDC));
+  }
+  static int32_t LogToPhys(HMONITOR aMonitor, double aValue);
+  static HMONITOR GetPrimaryMonitor();
+  static HMONITOR MonitorFromRect(const gfx::Rect& rect);
+
+  static bool HasSystemMetricsForDpi();
+  static int GetSystemMetricsForDpi(int nIndex, UINT dpi);
+
+  /**
+   * @param msg Windows event message
+   * @return User-friendly event name, or nullptr if no
+   *         match is found.
+   */
+  static const char* WinEventToEventName(UINT msg);
+
+  /**
+   * @param aHdc HDC for printer
+   * @return unwritable margins for currently set page on aHdc or empty margins
+   *         if aHdc is null
+   */
+  static gfx::MarginDouble GetUnwriteableMarginsForDeviceInInches(HDC aHdc);
+
+  static bool HasPackageIdentity() { return sHasPackageIdentity; }
+
+  /*
+   * The "family name" of a Windows app package is the full name without any of
+   * the components that might change during the life cycle of the app (such as
+   * the version number, or the architecture). This leaves only those properties
+   * which together serve to uniquely identify the app within one Windows
+   * installation, namely the base name and the publisher name. Meaning, this
+   * string is safe to use anywhere that a string uniquely identifying an app
+   * installation is called for (because multiple copies of the same app on the
+   * same system is not a supported feature in the app framework).
+   */
+  static nsString GetPackageFamilyName();
+
+  /**
+   * Logging helpers that dump output to prlog module 'Widget', console, and
+   * OutputDebugString. Note these output in both debug and release builds.
+   */
+  static void Log(const char* fmt, ...);
+  static void LogW(const wchar_t* fmt, ...);
+
+  /**
+   * PeekMessage() and GetMessage() are wrapper methods for PeekMessageW(),
+   * GetMessageW(), ITfMessageMgr::PeekMessageW() and
+   * ITfMessageMgr::GetMessageW().
+   * Don't call the native APIs directly.  You MUST use these methods instead.
+   */
+  static bool PeekMessage(LPMSG aMsg, HWND aWnd, UINT aFirstMessage,
+                          UINT aLastMessage, UINT aOption);
+  static bool GetMessage(LPMSG aMsg, HWND aWnd, UINT aFirstMessage,
+                         UINT aLastMessage);
+
+  /**
+   * Wait until a message is ready to be processed.
+   * Prefer using this method to directly calling ::WaitMessage since
+   * ::WaitMessage will wait if there is an unread message in the queue.
+   * That can cause freezes until another message enters the queue if the
+   * message is marked read by a call to PeekMessage which the caller is
+   * not aware of (e.g., from a different thread).
+   * Note that this method may cause sync dispatch of sent (as opposed to
+   * posted) messages.
+   * @param aTimeoutMs Timeout for waiting in ms, defaults to INFINITE
+   */
+  static void WaitForMessage(DWORD aTimeoutMs = INFINITE);
+
+  /**
+   * GetTopLevelHWND() returns a window handle of the top level window which
+   * aWnd belongs to.  Note that the result may not be our window, i.e., it
+   * may not be managed by nsWindow.
+   *
+   * See follwing table for the detail of the result window type.
+   *
+   * +-------------------------+-----------------------------------------------+
+   * |                         |                aStopIfNotPopup                |
+   * +-------------------------+-----------------------+-----------------------+
+   * |                         |         TRUE          |         FALSE         |
+   + +-----------------+-------+-----------------------+-----------------------+
+   * |                 |       |  * an independent top level window            |
+   * |                 | TRUE  |  * a pupup window (WS_POPUP)                  |
+   * |                 |       |  * an owned top level window (like dialog)    |
+   * | aStopIfNotChild +-------+-----------------------+-----------------------+
+   * |                 |       |  * independent window | * only an independent |
+   * |                 | FALSE |  * non-popup-owned-   |   top level window    |
+   * |                 |       |    window like dialog |                       |
+   * +-----------------+-------+-----------------------+-----------------------+
+   */
+  static HWND GetTopLevelHWND(HWND aWnd, bool aStopIfNotChild = false,
+                              bool aStopIfNotPopup = true);
+
+  /**
+   * SetNSWindowPtr() associates aWindow with aWnd. If aWidget is nullptr, it
+   * instead dissociates any nsWindow from aWnd.
+   *
+   * No AddRef is performed. May not be used off of the main thread.
+   */
+  static void SetNSWindowPtr(HWND aWnd, nsWindow* aWindow);
+  /**
+   * GetNSWindowPtr() returns a pointer to the associated nsWindow pointer, if
+   * one exists, or nullptr, if not.
+   *
+   * No AddRef is performed. May not be used off of the main thread.
+   */
+  static nsWindow* GetNSWindowPtr(HWND aWnd);
+
+  /**
+   * IsOurProcessWindow() returns TRUE if aWnd belongs our process.
+   * Otherwise, FALSE.
+   */
+  static bool IsOurProcessWindow(HWND aWnd);
+
+  /**
+   * FindOurProcessWindow() returns the nearest ancestor window which
+   * belongs to our process.  If it fails to find our process's window by the
+   * top level window, returns nullptr.  And note that this is using
+   * ::GetParent() for climbing the window hierarchy, therefore, it gives
+   * up at an owned top level window except popup window (e.g., dialog).
+   */
+  static HWND FindOurProcessWindow(HWND aWnd);
+
+  /**
+   * FindOurWindowAtPoint() returns the topmost child window which belongs to
+   * our process's top level window.
+   *
+   * NOTE: the topmost child window may NOT be our process's window like a
+   *       plugin's window.
+   */
+  static HWND FindOurWindowAtPoint(const POINT& aPointInScreen);
+
+  /**
+   * InitMSG() returns an MSG struct which was initialized by the params.
+   * Don't trust the other members in the result.
+   */
+  static MSG InitMSG(UINT aMessage, WPARAM wParam, LPARAM lParam, HWND aWnd);
+
+  /**
+   * GetScanCode() returns a scan code for the LPARAM of WM_KEYDOWN, WM_KEYUP,
+   * WM_CHAR and WM_UNICHAR.
+   *
+   */
+  static WORD GetScanCode(LPARAM aLParam) { return (aLParam >> 16) & 0xFF; }
+
+  /**
+   * IsExtendedScanCode() returns TRUE if the LPARAM indicates the key message
+   * is an extended key event.
+   */
+  static bool IsExtendedScanCode(LPARAM aLParam) {
+    return (aLParam & 0x1000000) != 0;
+  }
+
+  /**
+   * GetInternalMessage() converts a native message to an internal message.
+   * If there is no internal message for the given native message, returns
+   * the native message itself.
+   */
+  static UINT GetInternalMessage(UINT aNativeMessage);
+
+  /**
+   * GetNativeMessage() converts an internal message to a native message.
+   * If aInternalMessage is a native message, returns the native message itself.
+   */
+  static UINT GetNativeMessage(UINT aInternalMessage);
+
+  /**
+   * GetMouseInputSource() returns a pointing device information.  The value is
+   * one of MouseEvent_Binding::MOZ_SOURCE_*.  This method MUST be called during
+   * mouse message handling.
+   */
+  static uint16_t GetMouseInputSource();
+
+  /**
+   * Windows also fires mouse window messages for pens and touches, so we should
+   * retrieve their pointer ID on receiving mouse events as well. Please refer
+   * to
+   * https://msdn.microsoft.com/en-us/library/windows/desktop/ms703320(v=vs.85).aspx
+   */
+  static uint16_t GetMousePointerID();
+
+  static bool GetIsMouseFromTouch(EventMessage aEventType);
+
+  /**
+   * ConvertHRGNToRegion converts a Windows HRGN to an LayoutDeviceIntRegion.
+   *
+   * aRgn the HRGN to convert.
+   * returns the LayoutDeviceIntRegion.
+   */
+  static LayoutDeviceIntRegion ConvertHRGNToRegion(HRGN aRgn);
+
+  /**
+   * ToIntRect converts a Windows RECT to a LayoutDeviceIntRect.
+   *
+   * aRect the RECT to convert.
+   * returns the LayoutDeviceIntRect.
+   */
+  static LayoutDeviceIntRect ToIntRect(const RECT& aRect);
+
+  /**
+   * Returns true if the context or IME state is enabled.  Otherwise, false.
+   */
+  static bool IsIMEEnabled(const InputContext& aInputContext);
+  static bool IsIMEEnabled(IMEEnabled aIMEState);
+
+  /**
+   * Returns modifier key array for aModifiers.  This is for
+   * nsIWidget::SynthethizeNative*Event().
+   */
+  static void SetupKeyModifiersSequence(nsTArray<KeyPair>* aArray,
+                                        uint32_t aModifiers, UINT aMessage);
+
+  /**
+   * Does device have touch support
+   */
+  static uint32_t IsTouchDeviceSupportPresent();
+
+  /**
+   * The maximum number of simultaneous touch contacts supported by the device.
+   * In the case of devices with multiple digitizers (e.g. multiple touch
+   * screens), the value will be the maximum of the set of maximum supported
+   * contacts by each individual digitizer.
+   */
+  static uint32_t GetMaxTouchPoints();
+
+  /**
+   * Returns the windows power platform role, which is useful for detecting
+   * tablets.
+   */
+  static POWER_PLATFORM_ROLE GetPowerPlatformRole();
+
+  // For pointer and hover media queries features.
+  static PointerCapabilities GetPrimaryPointerCapabilities();
+  // For any-pointer and any-hover media queries features.
+  static PointerCapabilities GetAllPointerCapabilities();
+  // Returns a string containing a comma-separated list of Fluent IDs
+  // representing the currently active pointing devices
+  static void GetPointerExplanation(nsAString* aExplanation);
+
+  /**
+   * Fully resolves a path to its final path name. So if path contains
+   * junction points or symlinks to other folders, we'll resolve the path
+   * fully to the actual path that the links target.
+   *
+   * @param aPath path to be resolved.
+   * @return true if successful, including if nothing needs to be changed.
+   *         false if something failed or aPath does not exist, aPath will
+   *               remain unchanged.
+   */
+  static bool ResolveJunctionPointsAndSymLinks(std::wstring& aPath);
+  static bool ResolveJunctionPointsAndSymLinks(nsIFile* aPath);
+
+  /**
+   * Returns true if executable's path is on a network drive.
+   */
+  static bool RunningFromANetworkDrive();
+
+  static void Initialize();
+
+  static nsresult WriteBitmap(nsIFile* aFile,
+                              mozilla::gfx::SourceSurface* surface);
+  // This function is a helper, but it cannot be called from the main thread.
+  // Use the one above!
+  static nsresult WriteBitmap(nsIFile* aFile, imgIContainer* aImage);
+
+  /**
+   * Wrapper for PathCanonicalize().
+   * Upon success, the resulting output string length is <= MAX_PATH.
+   * @param  aPath [in,out] The path to transform.
+   * @return true on success, false on failure.
+   */
+  static bool CanonicalizePath(nsAString& aPath);
+
+  /**
+   * Converts short paths (e.g. "C:\\PROGRA~1\\XYZ") to full paths.
+   * Upon success, the resulting output string length is <= MAX_PATH.
+   * @param  aPath [in,out] The path to transform.
+   * @return true on success, false on failure.
+   */
+  static bool MakeLongPath(nsAString& aPath);
+
+  /**
+   * Wrapper for PathUnExpandEnvStringsW().
+   * Upon success, the resulting output string length is <= MAX_PATH.
+   * @param  aPath [in,out] The path to transform.
+   * @return true on success, false on failure.
+   */
+  static bool UnexpandEnvVars(nsAString& aPath);
+
+  /**
+   * Retrieve a semicolon-delimited list of DLL files derived from AppInit_DLLs
+   */
+  static bool GetAppInitDLLs(nsAString& aOutput);
+
+  enum class PathTransformFlags : uint32_t {
+    Canonicalize = 1,
+    Lengthen = 2,
+    UnexpandEnvVars = 4,
+    RequireFilePath = 8,
+
+    Default = 7,  // Default omits RequireFilePath
+  };
+
+  /**
+   * Given a path, transforms it in preparation to be reported via telemetry.
+   * That can include canonicalization, converting short to long paths,
+   * unexpanding environment strings, and removing potentially sensitive data
+   * from the path.
+   *
+   * @param  aPath  [in,out] The path to transform.
+   * @param  aFlags [in] Specifies which transformations to perform, allowing
+   *                the caller to skip operations they know have already been
+   *                performed.
+   * @return true on success, false on failure.
+   */
+  static bool PreparePathForTelemetry(
+      nsAString& aPath,
+      PathTransformFlags aFlags = PathTransformFlags::Default);
+
+  static const size_t kMaxWhitelistedItems = 3;
+  using WhitelistVec =
+      Vector<std::pair<nsString, nsDependentString>, kMaxWhitelistedItems>;
+
+  static const WhitelistVec& GetWhitelistedPaths();
+
+  static bool GetClassName(HWND aHwnd, nsAString& aName);
+
+  static void EnableWindowOcclusion(const bool aEnable);
+
+  static bool GetTimezoneName(wchar_t* aBuffer);
+
+#ifdef DEBUG
+  static nsresult SetHiDPIMode(bool aHiDPI);
+  static nsresult RestoreHiDPIMode();
+#endif
+
+  static bool GetAutoRotationState(AR_STATE* aRotationState);
+
+  static void GetClipboardFormatAsString(UINT aFormat, nsAString& aOutput);
+
+ private:
+  static WhitelistVec BuildWhitelist();
+
+ public:
+#ifdef ACCESSIBILITY
+  static a11y::LocalAccessible* GetRootAccessibleForHWND(HWND aHwnd);
+#endif
+};
+
+#ifdef MOZ_PLACES
+class AsyncFaviconDataReady final : public nsIFaviconDataCallback {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIFAVICONDATACALLBACK
+
+  AsyncFaviconDataReady(nsIURI* aNewURI, RefPtr<LazyIdleThread>& aIOThread,
+                        const bool aURLShortcut,
+                        already_AddRefed<nsIRunnable> aRunnable);
+  nsresult OnFaviconDataNotAvailable(void);
+
+ private:
+  ~AsyncFaviconDataReady() {}
+
+  nsCOMPtr<nsIURI> mNewURI;
+  RefPtr<LazyIdleThread> mIOThread;
+  nsCOMPtr<nsIRunnable> mRunnable;
+  const bool mURLShortcut;
+};
+#endif
+
+/**
+ * Asynchronously tries add the list to the build
+ */
+class AsyncEncodeAndWriteIcon : public nsIRunnable {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIRUNNABLE
+
+  // Warning: AsyncEncodeAndWriteIcon assumes ownership of the aData buffer
+  // passed in
+  AsyncEncodeAndWriteIcon(const nsAString& aIconPath,
+                          UniquePtr<uint8_t[]> aData, uint32_t aStride,
+                          uint32_t aWidth, uint32_t aHeight,
+                          already_AddRefed<nsIRunnable> aRunnable);
+
+ private:
+  virtual ~AsyncEncodeAndWriteIcon();
+
+  nsAutoString mIconPath;
+  UniquePtr<uint8_t[]> mBuffer;
+  nsCOMPtr<nsIRunnable> mRunnable;
+  uint32_t mStride;
+  uint32_t mWidth;
+  uint32_t mHeight;
+};
+
+class AsyncDeleteAllFaviconsFromDisk : public nsIRunnable {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIRUNNABLE
+
+  explicit AsyncDeleteAllFaviconsFromDisk(bool aIgnoreRecent = false);
+
+ private:
+  virtual ~AsyncDeleteAllFaviconsFromDisk();
+
+  int32_t mIcoNoDeleteSeconds;
+  bool mIgnoreRecent;
+  nsCOMPtr<nsIFile> mJumpListCacheDir;
+};
+
+class FaviconHelper {
+ public:
+  static const char kJumpListCacheDir[];
+  static const char kShortcutCacheDir[];
+  static nsresult ObtainCachedIconFile(
+      nsCOMPtr<nsIURI> aFaviconPageURI, nsString& aICOFilePath,
+      RefPtr<LazyIdleThread>& aIOThread, bool aURLShortcut,
+      already_AddRefed<nsIRunnable> aRunnable = nullptr);
+
+  static nsresult GetOutputIconPath(nsCOMPtr<nsIURI> aFaviconPageURI,
+                                    nsCOMPtr<nsIFile>& aICOFile,
+                                    bool aURLShortcut);
+
+  static nsresult CacheIconFileFromFaviconURIAsync(
+      nsCOMPtr<nsIURI> aFaviconPageURI, nsCOMPtr<nsIFile> aICOFile,
+      RefPtr<LazyIdleThread>& aIOThread, bool aURLShortcut,
+      already_AddRefed<nsIRunnable> aRunnable);
+
+  static int32_t GetICOCacheSecondsTimeout();
+};
+
+MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(WinUtils::PathTransformFlags);
+
+// RTL shim windows are temporary child windows of our nsWindows created to
+// address RTL issues in picker dialogs. (See bug 588735.)
+class ScopedRtlShimWindow {
+ public:
+  explicit ScopedRtlShimWindow(nsIWidget* aParent);
+  ~ScopedRtlShimWindow();
+
+  ScopedRtlShimWindow(const ScopedRtlShimWindow&) = delete;
+  ScopedRtlShimWindow(ScopedRtlShimWindow&& that) noexcept : mWnd(that.mWnd) {
+    that.mWnd = nullptr;
+  };
+
+  HWND get() const { return mWnd; }
+
+ private:
+  HWND mWnd;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // mozilla_widget_WinUtils_h__
diff --git a/widget/windows/WinWindowOcclusionTracker.cpp b/widget/windows/WinWindowOcclusionTracker.cpp
new file mode 100644
index 0000000000..a38f950585
--- /dev/null
+++ b/widget/windows/WinWindowOcclusionTracker.cpp
@@ -0,0 +1,1471 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <queue>
+#include <windows.h>
+#include <winuser.h>
+#include <wtsapi32.h>
+
+#include "WinWindowOcclusionTracker.h"
+
+#include "base/thread.h"
+#include "base/message_loop.h"
+#include "base/platform_thread.h"
+#include "gfxConfig.h"
+#include "nsThreadUtils.h"
+#include "mozilla/DataMutex.h"
+#include "mozilla/gfx/Logging.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/Logging.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/StaticPtr.h"
+#include "nsBaseWidget.h"
+#include "nsWindow.h"
+#include "transport/runnable_utils.h"
+#include "WinUtils.h"
+
+namespace mozilla::widget {
+
+// Can be called on Main thread
+LazyLogModule gWinOcclusionTrackerLog("WinOcclusionTracker");
+#define LOG(type, ...) MOZ_LOG(gWinOcclusionTrackerLog, type, (__VA_ARGS__))
+
+// Can be called on OcclusionCalculator thread
+LazyLogModule gWinOcclusionCalculatorLog("WinOcclusionCalculator");
+#define CALC_LOG(type, ...) \
+  MOZ_LOG(gWinOcclusionCalculatorLog, type, (__VA_ARGS__))
+
+// ~16 ms = time between frames when frame rate is 60 FPS.
+const int kOcclusionUpdateRunnableDelayMs = 16;
+
+class OcclusionUpdateRunnable : public CancelableRunnable {
+ public:
+  explicit OcclusionUpdateRunnable(
+      WinWindowOcclusionTracker::WindowOcclusionCalculator*
+          aOcclusionCalculator)
+      : CancelableRunnable("OcclusionUpdateRunnable"),
+        mOcclusionCalculator(aOcclusionCalculator) {
+    mTimeStamp = TimeStamp::Now();
+  }
+
+  NS_IMETHOD Run() override {
+    if (mIsCanceled) {
+      return NS_OK;
+    }
+    MOZ_ASSERT(WinWindowOcclusionTracker::IsInWinWindowOcclusionThread());
+
+    uint32_t latencyMs =
+        round((TimeStamp::Now() - mTimeStamp).ToMilliseconds());
+    CALC_LOG(LogLevel::Debug,
+             "ComputeNativeWindowOcclusionStatus() latencyMs %u", latencyMs);
+
+    mOcclusionCalculator->ComputeNativeWindowOcclusionStatus();
+    return NS_OK;
+  }
+
+  nsresult Cancel() override {
+    mIsCanceled = true;
+    mOcclusionCalculator = nullptr;
+    return NS_OK;
+  }
+
+ private:
+  bool mIsCanceled = false;
+  RefPtr<WinWindowOcclusionTracker::WindowOcclusionCalculator>
+      mOcclusionCalculator;
+  TimeStamp mTimeStamp;
+};
+
+// Used to serialize tasks related to mRootWindowHwndsOcclusionState.
+class SerializedTaskDispatcher {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(SerializedTaskDispatcher)
+
+ public:
+  SerializedTaskDispatcher();
+
+  void Destroy();
+  void PostTaskToMain(already_AddRefed<nsIRunnable> aTask);
+  void PostTaskToCalculator(already_AddRefed<nsIRunnable> aTask);
+  void PostDelayedTaskToCalculator(already_AddRefed<Runnable> aTask,
+                                   int aDelayMs);
+  bool IsOnCurrentThread();
+
+ private:
+  friend class DelayedTaskRunnable;
+
+  ~SerializedTaskDispatcher();
+
+  struct Data {
+    std::queue<std::pair<RefPtr<nsIRunnable>, RefPtr<nsISerialEventTarget>>>
+        mTasks;
+    bool mDestroyed = false;
+    RefPtr<Runnable> mCurrentRunnable;
+  };
+
+  void PostTasksIfNecessary(nsISerialEventTarget* aEventTarget,
+                            const DataMutex<Data>::AutoLock& aProofOfLock);
+  void HandleDelayedTask(already_AddRefed<nsIRunnable> aTask);
+  void HandleTasks();
+
+  // Hold current EventTarget during calling nsIRunnable::Run().
+  RefPtr<nsISerialEventTarget> mCurrentEventTarget = nullptr;
+
+  DataMutex<Data> mData;
+};
+
+class DelayedTaskRunnable : public Runnable {
+ public:
+  DelayedTaskRunnable(SerializedTaskDispatcher* aSerializedTaskDispatcher,
+                      already_AddRefed<Runnable> aTask)
+      : Runnable("DelayedTaskRunnable"),
+        mSerializedTaskDispatcher(aSerializedTaskDispatcher),
+        mTask(aTask) {}
+
+  NS_IMETHOD Run() override {
+    mSerializedTaskDispatcher->HandleDelayedTask(mTask.forget());
+    return NS_OK;
+  }
+
+ private:
+  RefPtr<SerializedTaskDispatcher> mSerializedTaskDispatcher;
+  RefPtr<Runnable> mTask;
+};
+
+SerializedTaskDispatcher::SerializedTaskDispatcher()
+    : mData("SerializedTaskDispatcher::mData") {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info,
+      "SerializedTaskDispatcher::SerializedTaskDispatcher() this %p", this);
+}
+
+SerializedTaskDispatcher::~SerializedTaskDispatcher() {
+#ifdef DEBUG
+  auto data = mData.Lock();
+  MOZ_ASSERT(data->mDestroyed);
+  MOZ_ASSERT(data->mTasks.empty());
+#endif
+}
+
+void SerializedTaskDispatcher::Destroy() {
+  MOZ_RELEASE_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info, "SerializedTaskDispatcher::Destroy() this %p", this);
+
+  auto data = mData.Lock();
+  if (data->mDestroyed) {
+    return;
+  }
+
+  data->mDestroyed = true;
+  std::queue<std::pair<RefPtr<nsIRunnable>, RefPtr<nsISerialEventTarget>>>
+      empty;
+  std::swap(data->mTasks, empty);
+}
+
+void SerializedTaskDispatcher::PostTaskToMain(
+    already_AddRefed<nsIRunnable> aTask) {
+  RefPtr<nsIRunnable> task = aTask;
+
+  auto data = mData.Lock();
+  if (data->mDestroyed) {
+    return;
+  }
+
+  nsISerialEventTarget* eventTarget = GetMainThreadSerialEventTarget();
+  data->mTasks.push({std::move(task), eventTarget});
+
+  MOZ_ASSERT_IF(!data->mCurrentRunnable, data->mTasks.size() == 1);
+  PostTasksIfNecessary(eventTarget, data);
+}
+
+void SerializedTaskDispatcher::PostTaskToCalculator(
+    already_AddRefed<nsIRunnable> aTask) {
+  RefPtr<nsIRunnable> task = aTask;
+
+  auto data = mData.Lock();
+  if (data->mDestroyed) {
+    return;
+  }
+
+  nsISerialEventTarget* eventTarget =
+      WinWindowOcclusionTracker::OcclusionCalculatorLoop()->SerialEventTarget();
+  data->mTasks.push({std::move(task), eventTarget});
+
+  MOZ_ASSERT_IF(!data->mCurrentRunnable, data->mTasks.size() == 1);
+  PostTasksIfNecessary(eventTarget, data);
+}
+
+void SerializedTaskDispatcher::PostDelayedTaskToCalculator(
+    already_AddRefed<Runnable> aTask, int aDelayMs) {
+  CALC_LOG(LogLevel::Debug,
+           "SerializedTaskDispatcher::PostDelayedTaskToCalculator()");
+
+  RefPtr<DelayedTaskRunnable> runnable =
+      new DelayedTaskRunnable(this, std::move(aTask));
+  MessageLoop* targetLoop =
+      WinWindowOcclusionTracker::OcclusionCalculatorLoop();
+  targetLoop->PostDelayedTask(runnable.forget(), aDelayMs);
+}
+
+bool SerializedTaskDispatcher::IsOnCurrentThread() {
+  return !!mCurrentEventTarget;
+}
+
+void SerializedTaskDispatcher::PostTasksIfNecessary(
+    nsISerialEventTarget* aEventTarget,
+    const DataMutex<Data>::AutoLock& aProofOfLock) {
+  MOZ_ASSERT(!aProofOfLock->mTasks.empty());
+
+  if (aProofOfLock->mCurrentRunnable) {
+    return;
+  }
+
+  RefPtr<Runnable> runnable =
+      WrapRunnable(RefPtr<SerializedTaskDispatcher>(this),
+                   &SerializedTaskDispatcher::HandleTasks);
+  aProofOfLock->mCurrentRunnable = runnable;
+  aEventTarget->Dispatch(runnable.forget());
+}
+
+void SerializedTaskDispatcher::HandleDelayedTask(
+    already_AddRefed<nsIRunnable> aTask) {
+  MOZ_ASSERT(WinWindowOcclusionTracker::IsInWinWindowOcclusionThread());
+  CALC_LOG(LogLevel::Debug, "SerializedTaskDispatcher::HandleDelayedTask()");
+
+  RefPtr<nsIRunnable> task = aTask;
+
+  auto data = mData.Lock();
+  if (data->mDestroyed) {
+    return;
+  }
+
+  nsISerialEventTarget* eventTarget =
+      WinWindowOcclusionTracker::OcclusionCalculatorLoop()->SerialEventTarget();
+  data->mTasks.push({std::move(task), eventTarget});
+
+  MOZ_ASSERT_IF(!data->mCurrentRunnable, data->mTasks.size() == 1);
+  PostTasksIfNecessary(eventTarget, data);
+}
+
+void SerializedTaskDispatcher::HandleTasks() {
+  RefPtr<nsIRunnable> frontTask;
+
+  // Get front task
+  {
+    auto data = mData.Lock();
+    if (data->mDestroyed) {
+      return;
+    }
+    MOZ_RELEASE_ASSERT(data->mCurrentRunnable);
+    MOZ_RELEASE_ASSERT(!data->mTasks.empty());
+
+    frontTask = data->mTasks.front().first;
+
+    MOZ_RELEASE_ASSERT(!mCurrentEventTarget);
+    mCurrentEventTarget = data->mTasks.front().second;
+  }
+
+  while (frontTask) {
+    if (NS_IsMainThread()) {
+      LOG(LogLevel::Debug, "SerializedTaskDispatcher::HandleTasks()");
+    } else {
+      CALC_LOG(LogLevel::Debug, "SerializedTaskDispatcher::HandleTasks()");
+    }
+
+    MOZ_ASSERT_IF(NS_IsMainThread(),
+                  mCurrentEventTarget == GetMainThreadSerialEventTarget());
+    MOZ_ASSERT_IF(
+        !NS_IsMainThread(),
+        mCurrentEventTarget == MessageLoop::current()->SerialEventTarget());
+
+    frontTask->Run();
+
+    // Get next task
+    {
+      auto data = mData.Lock();
+      if (data->mDestroyed) {
+        return;
+      }
+
+      frontTask = nullptr;
+      data->mTasks.pop();
+      // Check if next task could be handled on current thread
+      if (!data->mTasks.empty() &&
+          data->mTasks.front().second == mCurrentEventTarget) {
+        frontTask = data->mTasks.front().first;
+      }
+    }
+  }
+
+  MOZ_ASSERT(!frontTask);
+
+  // Post tasks to different thread if pending tasks exist.
+  {
+    auto data = mData.Lock();
+    data->mCurrentRunnable = nullptr;
+    mCurrentEventTarget = nullptr;
+
+    if (data->mDestroyed || data->mTasks.empty()) {
+      return;
+    }
+
+    PostTasksIfNecessary(data->mTasks.front().second, data);
+  }
+}
+
+// static
+StaticRefPtr<WinWindowOcclusionTracker> WinWindowOcclusionTracker::sTracker;
+
+/* static */
+WinWindowOcclusionTracker* WinWindowOcclusionTracker::Get() {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (!sTracker || sTracker->mHasAttemptedShutdown) {
+    return nullptr;
+  }
+  return sTracker;
+}
+
+/* static */
+void WinWindowOcclusionTracker::Ensure() {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info, "WinWindowOcclusionTracker::Ensure()");
+
+  base::Thread::Options options;
+  options.message_loop_type = MessageLoop::TYPE_UI;
+
+  if (sTracker) {
+    // Try to reuse the thread, which involves stopping and restarting it.
+    sTracker->mThread->Stop();
+    if (sTracker->mThread->StartWithOptions(options)) {
+      // Success!
+      sTracker->mHasAttemptedShutdown = false;
+
+      // Take this opportunity to ensure that mDisplayStatusObserver and
+      // mSessionChangeObserver exist. They might have failed to be
+      // created when sTracker was created.
+      sTracker->EnsureDisplayStatusObserver();
+      sTracker->EnsureSessionChangeObserver();
+      return;
+    }
+    // Restart failed, so null out our sTracker and try again with a new
+    // thread. This will cause the old singleton instance to be deallocated,
+    // which will destroy its mThread as well.
+    sTracker = nullptr;
+  }
+
+  UniquePtr<base::Thread> thread =
+      MakeUnique<base::Thread>("WinWindowOcclusionCalc");
+
+  if (!thread->StartWithOptions(options)) {
+    return;
+  }
+
+  sTracker = new WinWindowOcclusionTracker(std::move(thread));
+  WindowOcclusionCalculator::CreateInstance();
+
+  RefPtr<Runnable> runnable =
+      WrapRunnable(RefPtr<WindowOcclusionCalculator>(
+                       WindowOcclusionCalculator::GetInstance()),
+                   &WindowOcclusionCalculator::Initialize);
+  sTracker->mSerializedTaskDispatcher->PostTaskToCalculator(runnable.forget());
+}
+
+/* static */
+void WinWindowOcclusionTracker::ShutDown() {
+  if (!sTracker) {
+    return;
+  }
+
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info, "WinWindowOcclusionTracker::ShutDown()");
+
+  sTracker->mHasAttemptedShutdown = true;
+  sTracker->Destroy();
+
+  // Our thread could hang while we're waiting for it to stop.
+  // Since we're shutting down, that's not a critical problem.
+  // We set a reasonable amount of time to wait for shutdown,
+  // and if it succeeds within that time, we correctly stop
+  // our thread by nulling out the refptr, which will cause it
+  // to be deallocated and join the thread. If it times out,
+  // we do nothing, which means that the thread will not be
+  // joined and sTracker memory will leak.
+  CVStatus status;
+  {
+    // It's important to hold the lock before posting the
+    // runnable. This ensures that the runnable can't begin
+    // until we've started our Wait, which prevents us from
+    // Waiting on a monitor that has already been notified.
+    MonitorAutoLock lock(sTracker->mMonitor);
+
+    static const TimeDuration TIMEOUT = TimeDuration::FromSeconds(2.0);
+    RefPtr<Runnable> runnable =
+        WrapRunnable(RefPtr<WindowOcclusionCalculator>(
+                         WindowOcclusionCalculator::GetInstance()),
+                     &WindowOcclusionCalculator::Shutdown);
+    OcclusionCalculatorLoop()->PostTask(runnable.forget());
+
+    // Monitor uses SleepConditionVariableSRW, which can have
+    // spurious wakeups which are reported as timeouts, so we
+    // check timestamps to ensure that we've waited as long we
+    // intended to. If we wake early, we don't bother calculating
+    // a precise amount for the next wait; we just wait the same
+    // amount of time. This means timeout might happen after as
+    // much as 2x the TIMEOUT time.
+    TimeStamp timeStart = TimeStamp::NowLoRes();
+    do {
+      status = sTracker->mMonitor.Wait(TIMEOUT);
+    } while ((status == CVStatus::Timeout) &&
+             ((TimeStamp::NowLoRes() - timeStart) < TIMEOUT));
+  }
+
+  if (status == CVStatus::NoTimeout) {
+    WindowOcclusionCalculator::ClearInstance();
+    sTracker = nullptr;
+  }
+}
+
+void WinWindowOcclusionTracker::Destroy() {
+  if (mDisplayStatusObserver) {
+    mDisplayStatusObserver->Destroy();
+    mDisplayStatusObserver = nullptr;
+  }
+  if (mSessionChangeObserver) {
+    mSessionChangeObserver->Destroy();
+    mSessionChangeObserver = nullptr;
+  }
+  if (mSerializedTaskDispatcher) {
+    mSerializedTaskDispatcher->Destroy();
+  }
+}
+
+/* static */
+MessageLoop* WinWindowOcclusionTracker::OcclusionCalculatorLoop() {
+  return sTracker ? sTracker->mThread->message_loop() : nullptr;
+}
+
+/* static */
+bool WinWindowOcclusionTracker::IsInWinWindowOcclusionThread() {
+  return sTracker &&
+         sTracker->mThread->thread_id() == PlatformThread::CurrentId();
+}
+
+void WinWindowOcclusionTracker::EnsureDisplayStatusObserver() {
+  if (mDisplayStatusObserver) {
+    return;
+  }
+  if (StaticPrefs::
+          widget_windows_window_occlusion_tracking_display_state_enabled()) {
+    mDisplayStatusObserver = DisplayStatusObserver::Create(this);
+  }
+}
+
+void WinWindowOcclusionTracker::EnsureSessionChangeObserver() {
+  if (mSessionChangeObserver) {
+    return;
+  }
+  if (StaticPrefs::
+          widget_windows_window_occlusion_tracking_session_lock_enabled()) {
+    mSessionChangeObserver = SessionChangeObserver::Create(this);
+  }
+}
+
+void WinWindowOcclusionTracker::Enable(nsBaseWidget* aWindow, HWND aHwnd) {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info, "WinWindowOcclusionTracker::Enable() aWindow %p aHwnd %p",
+      aWindow, aHwnd);
+
+  auto it = mHwndRootWindowMap.find(aHwnd);
+  if (it != mHwndRootWindowMap.end()) {
+    return;
+  }
+
+  nsWeakPtr weak = do_GetWeakReference(aWindow);
+  mHwndRootWindowMap.emplace(aHwnd, weak);
+
+  RefPtr<Runnable> runnable = WrapRunnable(
+      RefPtr<WindowOcclusionCalculator>(
+          WindowOcclusionCalculator::GetInstance()),
+      &WindowOcclusionCalculator::EnableOcclusionTrackingForWindow, aHwnd);
+  mSerializedTaskDispatcher->PostTaskToCalculator(runnable.forget());
+}
+
+void WinWindowOcclusionTracker::Disable(nsBaseWidget* aWindow, HWND aHwnd) {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info,
+      "WinWindowOcclusionTracker::Disable() aWindow %p aHwnd %p", aWindow,
+      aHwnd);
+
+  auto it = mHwndRootWindowMap.find(aHwnd);
+  if (it == mHwndRootWindowMap.end()) {
+    return;
+  }
+
+  mHwndRootWindowMap.erase(it);
+
+  RefPtr<Runnable> runnable = WrapRunnable(
+      RefPtr<WindowOcclusionCalculator>(
+          WindowOcclusionCalculator::GetInstance()),
+      &WindowOcclusionCalculator::DisableOcclusionTrackingForWindow, aHwnd);
+  mSerializedTaskDispatcher->PostTaskToCalculator(runnable.forget());
+}
+
+void WinWindowOcclusionTracker::OnWindowVisibilityChanged(nsBaseWidget* aWindow,
+                                                          bool aVisible) {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info,
+      "WinWindowOcclusionTracker::OnWindowVisibilityChanged() aWindow %p "
+      "aVisible %d",
+      aWindow, aVisible);
+
+  RefPtr<Runnable> runnable = WrapRunnable(
+      RefPtr<WindowOcclusionCalculator>(
+          WindowOcclusionCalculator::GetInstance()),
+      &WindowOcclusionCalculator::HandleVisibilityChanged, aVisible);
+  mSerializedTaskDispatcher->PostTaskToCalculator(runnable.forget());
+}
+
+WinWindowOcclusionTracker::WinWindowOcclusionTracker(
+    UniquePtr<base::Thread> aThread)
+    : mThread(std::move(aThread)), mMonitor("WinWindowOcclusionTracker") {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info, "WinWindowOcclusionTracker::WinWindowOcclusionTracker()");
+
+  EnsureDisplayStatusObserver();
+  EnsureSessionChangeObserver();
+
+  mSerializedTaskDispatcher = new SerializedTaskDispatcher();
+}
+
+WinWindowOcclusionTracker::~WinWindowOcclusionTracker() {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info,
+      "WinWindowOcclusionTracker::~WinWindowOcclusionTracker()");
+}
+
+// static
+bool WinWindowOcclusionTracker::IsWindowVisibleAndFullyOpaque(
+    HWND aHwnd, LayoutDeviceIntRect* aWindowRect) {
+  // Filter out windows that are not "visible", IsWindowVisible().
+  if (!::IsWindow(aHwnd) || !::IsWindowVisible(aHwnd)) {
+    return false;
+  }
+
+  // Filter out minimized windows.
+  if (::IsIconic(aHwnd)) {
+    return false;
+  }
+
+  LONG exStyles = ::GetWindowLong(aHwnd, GWL_EXSTYLE);
+  // Filter out "transparent" windows, windows where the mouse clicks fall
+  // through them.
+  if (exStyles & WS_EX_TRANSPARENT) {
+    return false;
+  }
+
+  // Filter out "tool windows", which are floating windows that do not appear on
+  // the taskbar or ALT-TAB. Floating windows can have larger window rectangles
+  // than what is visible to the user, so by filtering them out we will avoid
+  // incorrectly marking native windows as occluded. We do not filter out the
+  // Windows Taskbar.
+  if (exStyles & WS_EX_TOOLWINDOW) {
+    nsAutoString className;
+    if (WinUtils::GetClassName(aHwnd, className)) {
+      if (!className.Equals(L"Shell_TrayWnd")) {
+        return false;
+      }
+    }
+  }
+
+  // Filter out layered windows that are not opaque or that set a transparency
+  // colorkey.
+  if (exStyles & WS_EX_LAYERED) {
+    BYTE alpha;
+    DWORD flags;
+
+    // GetLayeredWindowAttributes only works if the application has
+    // previously called SetLayeredWindowAttributes on the window.
+    // The function will fail if the layered window was setup with
+    // UpdateLayeredWindow. Treat this failure as the window being transparent.
+    // See Remarks section of
+    // https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getlayeredwindowattributes
+    if (!::GetLayeredWindowAttributes(aHwnd, nullptr, &alpha, &flags)) {
+      return false;
+    }
+
+    if (flags & LWA_ALPHA && alpha < 255) {
+      return false;
+    }
+    if (flags & LWA_COLORKEY) {
+      return false;
+    }
+  }
+
+  // Filter out windows that do not have a simple rectangular region.
+  HRGN region = ::CreateRectRgn(0, 0, 0, 0);
+  int result = GetWindowRgn(aHwnd, region);
+  ::DeleteObject(region);
+  if (result == COMPLEXREGION) {
+    return false;
+  }
+
+  // Windows 10 has cloaked windows, windows with WS_VISIBLE attribute but
+  // not displayed. explorer.exe, in particular has one that's the
+  // size of the desktop. It's usually behind Chrome windows in the z-order,
+  // but using a remote desktop can move it up in the z-order. So, ignore them.
+  DWORD reason;
+  if (SUCCEEDED(::DwmGetWindowAttribute(aHwnd, DWMWA_CLOAKED, &reason,
+                                        sizeof(reason))) &&
+      reason != 0) {
+    return false;
+  }
+
+  RECT winRect;
+  // Filter out windows that take up zero area. The call to GetWindowRect is one
+  // of the most expensive parts of this function, so it is last.
+  if (!::GetWindowRect(aHwnd, &winRect)) {
+    return false;
+  }
+  if (::IsRectEmpty(&winRect)) {
+    return false;
+  }
+
+  // Ignore popup windows since they're transient unless it is the Windows
+  // Taskbar
+  // XXX Chrome Widget popup handling is removed for now.
+  if (::GetWindowLong(aHwnd, GWL_STYLE) & WS_POPUP) {
+    nsAutoString className;
+    if (WinUtils::GetClassName(aHwnd, className)) {
+      if (!className.Equals(L"Shell_TrayWnd")) {
+        return false;
+      }
+    }
+  }
+
+  *aWindowRect = LayoutDeviceIntRect(winRect.left, winRect.top,
+                                     winRect.right - winRect.left,
+                                     winRect.bottom - winRect.top);
+
+  WINDOWPLACEMENT windowPlacement = {0};
+  windowPlacement.length = sizeof(WINDOWPLACEMENT);
+  ::GetWindowPlacement(aHwnd, &windowPlacement);
+  if (windowPlacement.showCmd == SW_MAXIMIZE) {
+    // If the window is maximized the window border extends beyond the visible
+    // region of the screen.  Adjust the maximized window rect to fit the
+    // screen dimensions to ensure that fullscreen windows, which do not extend
+    // beyond the screen boundaries since they typically have no borders, will
+    // occlude maximized windows underneath them.
+    HMONITOR hmon = ::MonitorFromWindow(aHwnd, MONITOR_DEFAULTTONEAREST);
+    if (hmon) {
+      MONITORINFO mi;
+      mi.cbSize = sizeof(mi);
+      if (GetMonitorInfo(hmon, &mi)) {
+        LayoutDeviceIntRect workArea(mi.rcWork.left, mi.rcWork.top,
+                                     mi.rcWork.right - mi.rcWork.left,
+                                     mi.rcWork.bottom - mi.rcWork.top);
+        // Adjust aWindowRect to fit to monitor.
+        aWindowRect->width = std::min(workArea.width, aWindowRect->width);
+        if (aWindowRect->x < workArea.x) {
+          aWindowRect->x = workArea.x;
+        } else {
+          aWindowRect->x = std::min(workArea.x + workArea.width,
+                                    aWindowRect->x + aWindowRect->width) -
+                           aWindowRect->width;
+        }
+        aWindowRect->height = std::min(workArea.height, aWindowRect->height);
+        if (aWindowRect->y < workArea.y) {
+          aWindowRect->y = workArea.y;
+        } else {
+          aWindowRect->y = std::min(workArea.y + workArea.height,
+                                    aWindowRect->y + aWindowRect->height) -
+                           aWindowRect->height;
+        }
+      }
+    }
+  }
+
+  return true;
+}
+
+// static
+void WinWindowOcclusionTracker::CallUpdateOcclusionState(
+    std::unordered_map<HWND, OcclusionState>* aMap, bool aShowAllWindows) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  auto* tracker = WinWindowOcclusionTracker::Get();
+  if (!tracker) {
+    return;
+  }
+  tracker->UpdateOcclusionState(aMap, aShowAllWindows);
+}
+
+void WinWindowOcclusionTracker::UpdateOcclusionState(
+    std::unordered_map<HWND, OcclusionState>* aMap, bool aShowAllWindows) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mSerializedTaskDispatcher->IsOnCurrentThread());
+  LOG(LogLevel::Debug,
+      "WinWindowOcclusionTracker::UpdateOcclusionState() aShowAllWindows %d",
+      aShowAllWindows);
+
+  mNumVisibleRootWindows = 0;
+  for (auto& [hwnd, state] : *aMap) {
+    auto it = mHwndRootWindowMap.find(hwnd);
+    // The window was destroyed while processing occlusion.
+    if (it == mHwndRootWindowMap.end()) {
+      continue;
+    }
+    auto occlState = state;
+
+    // If the screen is locked or off, ignore occlusion state results and
+    // mark the window as occluded.
+    if (mScreenLocked || !mDisplayOn) {
+      occlState = OcclusionState::OCCLUDED;
+    } else if (aShowAllWindows) {
+      occlState = OcclusionState::VISIBLE;
+    }
+    nsCOMPtr<nsIWidget> widget = do_QueryReferent(it->second);
+    if (!widget) {
+      continue;
+    }
+    auto* baseWidget = static_cast<nsBaseWidget*>(widget.get());
+    baseWidget->NotifyOcclusionState(occlState);
+    if (baseWidget->SizeMode() != nsSizeMode_Minimized) {
+      mNumVisibleRootWindows++;
+    }
+  }
+}
+
+void WinWindowOcclusionTracker::OnSessionChange(WPARAM aStatusCode,
+                                                Maybe<bool> aIsCurrentSession) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (aIsCurrentSession.isNothing() || !*aIsCurrentSession) {
+    return;
+  }
+
+  if (aStatusCode == WTS_SESSION_UNLOCK) {
+    LOG(LogLevel::Info,
+        "WinWindowOcclusionTracker::OnSessionChange() WTS_SESSION_UNLOCK");
+
+    // UNLOCK will cause a foreground window change, which will
+    // trigger an occlusion calculation on its own.
+    mScreenLocked = false;
+  } else if (aStatusCode == WTS_SESSION_LOCK) {
+    LOG(LogLevel::Info,
+        "WinWindowOcclusionTracker::OnSessionChange() WTS_SESSION_LOCK");
+
+    mScreenLocked = true;
+    MarkNonIconicWindowsOccluded();
+  }
+}
+
+void WinWindowOcclusionTracker::OnDisplayStateChanged(bool aDisplayOn) {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info,
+      "WinWindowOcclusionTracker::OnDisplayStateChanged() aDisplayOn %d",
+      aDisplayOn);
+
+  if (mDisplayOn == aDisplayOn) {
+    return;
+  }
+
+  mDisplayOn = aDisplayOn;
+  if (aDisplayOn) {
+    // Notify the window occlusion calculator of the display turning on
+    // which will schedule an occlusion calculation. This must be run
+    // on the WindowOcclusionCalculator thread.
+    RefPtr<Runnable> runnable =
+        WrapRunnable(RefPtr<WindowOcclusionCalculator>(
+                         WindowOcclusionCalculator::GetInstance()),
+                     &WindowOcclusionCalculator::HandleVisibilityChanged,
+                     /* aVisible */ true);
+    mSerializedTaskDispatcher->PostTaskToCalculator(runnable.forget());
+  } else {
+    MarkNonIconicWindowsOccluded();
+  }
+}
+
+void WinWindowOcclusionTracker::MarkNonIconicWindowsOccluded() {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info,
+      "WinWindowOcclusionTracker::MarkNonIconicWindowsOccluded()");
+
+  // Set all visible root windows as occluded. If not visible,
+  // set them as hidden.
+  for (auto& [hwnd, weak] : mHwndRootWindowMap) {
+    nsCOMPtr<nsIWidget> widget = do_QueryReferent(weak);
+    if (!widget) {
+      continue;
+    }
+    auto* baseWidget = static_cast<nsBaseWidget*>(widget.get());
+    auto state = (baseWidget->SizeMode() == nsSizeMode_Minimized)
+                     ? OcclusionState::HIDDEN
+                     : OcclusionState::OCCLUDED;
+    baseWidget->NotifyOcclusionState(state);
+  }
+}
+
+void WinWindowOcclusionTracker::TriggerCalculation() {
+  RefPtr<Runnable> runnable =
+      WrapRunnable(RefPtr<WindowOcclusionCalculator>(
+                       WindowOcclusionCalculator::GetInstance()),
+                   &WindowOcclusionCalculator::HandleTriggerCalculation);
+  mSerializedTaskDispatcher->PostTaskToCalculator(runnable.forget());
+}
+
+// static
+BOOL WinWindowOcclusionTracker::DumpOccludingWindowsCallback(HWND aHWnd,
+                                                             LPARAM aLParam) {
+  HWND hwnd = reinterpret_cast<HWND>(aLParam);
+
+  LayoutDeviceIntRect windowRect;
+  bool windowIsOccluding = IsWindowVisibleAndFullyOpaque(aHWnd, &windowRect);
+  if (windowIsOccluding) {
+    nsAutoString className;
+    if (WinUtils::GetClassName(aHWnd, className)) {
+      const auto name = NS_ConvertUTF16toUTF8(className);
+      printf_stderr(
+          "DumpOccludingWindowsCallback() aHWnd %p className %s windowRect(%d, "
+          "%d, %d, %d)\n",
+          aHWnd, name.get(), windowRect.x, windowRect.y, windowRect.width,
+          windowRect.height);
+    }
+  }
+
+  if (aHWnd == hwnd) {
+    return false;
+  }
+  return true;
+}
+
+void WinWindowOcclusionTracker::DumpOccludingWindows(HWND aHWnd) {
+  printf_stderr("DumpOccludingWindows() until aHWnd %p visible %d iconic %d\n",
+                aHWnd, ::IsWindowVisible(aHWnd), ::IsIconic(aHWnd));
+  ::EnumWindows(&DumpOccludingWindowsCallback, reinterpret_cast<LPARAM>(aHWnd));
+}
+
+// static
+StaticRefPtr<WinWindowOcclusionTracker::WindowOcclusionCalculator>
+    WinWindowOcclusionTracker::WindowOcclusionCalculator::sCalculator;
+
+WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    WindowOcclusionCalculator()
+    : mMonitor(WinWindowOcclusionTracker::Get()->mMonitor) {
+  MOZ_ASSERT(NS_IsMainThread());
+  LOG(LogLevel::Info, "WindowOcclusionCalculator()");
+
+  mSerializedTaskDispatcher =
+      WinWindowOcclusionTracker::Get()->GetSerializedTaskDispatcher();
+}
+
+WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    ~WindowOcclusionCalculator() {}
+
+// static
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::CreateInstance() {
+  MOZ_ASSERT(NS_IsMainThread());
+  sCalculator = new WindowOcclusionCalculator();
+}
+
+// static
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::ClearInstance() {
+  MOZ_ASSERT(NS_IsMainThread());
+  sCalculator = nullptr;
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::Initialize() {
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+  MOZ_ASSERT(!mVirtualDesktopManager);
+  CALC_LOG(LogLevel::Info, "Initialize()");
+
+#ifndef __MINGW32__
+  RefPtr<IVirtualDesktopManager> desktopManager;
+  HRESULT hr = ::CoCreateInstance(
+      CLSID_VirtualDesktopManager, NULL, CLSCTX_INPROC_SERVER,
+      __uuidof(IVirtualDesktopManager), getter_AddRefs(desktopManager));
+  if (FAILED(hr)) {
+    return;
+  }
+  mVirtualDesktopManager = desktopManager;
+#endif
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::Shutdown() {
+  MonitorAutoLock lock(mMonitor);
+
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+  CALC_LOG(LogLevel::Info, "Shutdown()");
+
+  UnregisterEventHooks();
+  if (mOcclusionUpdateRunnable) {
+    mOcclusionUpdateRunnable->Cancel();
+    mOcclusionUpdateRunnable = nullptr;
+  }
+  mVirtualDesktopManager = nullptr;
+
+  mMonitor.NotifyAll();
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    EnableOcclusionTrackingForWindow(HWND aHwnd) {
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+  MOZ_ASSERT(mSerializedTaskDispatcher->IsOnCurrentThread());
+  CALC_LOG(LogLevel::Info, "EnableOcclusionTrackingForWindow() aHwnd %p",
+           aHwnd);
+
+  MOZ_RELEASE_ASSERT(mRootWindowHwndsOcclusionState.find(aHwnd) ==
+                     mRootWindowHwndsOcclusionState.end());
+  mRootWindowHwndsOcclusionState[aHwnd] = OcclusionState::UNKNOWN;
+
+  if (mGlobalEventHooks.empty()) {
+    RegisterEventHooks();
+  }
+
+  // Schedule an occlusion calculation so that the newly tracked window does
+  // not have a stale occlusion status.
+  ScheduleOcclusionCalculationIfNeeded();
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    DisableOcclusionTrackingForWindow(HWND aHwnd) {
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+  MOZ_ASSERT(mSerializedTaskDispatcher->IsOnCurrentThread());
+  CALC_LOG(LogLevel::Info, "DisableOcclusionTrackingForWindow() aHwnd %p",
+           aHwnd);
+
+  MOZ_RELEASE_ASSERT(mRootWindowHwndsOcclusionState.find(aHwnd) !=
+                     mRootWindowHwndsOcclusionState.end());
+  mRootWindowHwndsOcclusionState.erase(aHwnd);
+
+  if (mMovingWindow == aHwnd) {
+    mMovingWindow = 0;
+  }
+
+  if (mRootWindowHwndsOcclusionState.empty()) {
+    UnregisterEventHooks();
+    if (mOcclusionUpdateRunnable) {
+      mOcclusionUpdateRunnable->Cancel();
+      mOcclusionUpdateRunnable = nullptr;
+    }
+  }
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    HandleVisibilityChanged(bool aVisible) {
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+  CALC_LOG(LogLevel::Info, "HandleVisibilityChange() aVisible %d", aVisible);
+
+  // May have gone from having no visible windows to having one, in
+  // which case we need to register event hooks, and make sure that an
+  // occlusion calculation is scheduled.
+  if (aVisible) {
+    MaybeRegisterEventHooks();
+    ScheduleOcclusionCalculationIfNeeded();
+  }
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    HandleTriggerCalculation() {
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+  CALC_LOG(LogLevel::Info, "HandleTriggerCalculation()");
+
+  MaybeRegisterEventHooks();
+  ScheduleOcclusionCalculationIfNeeded();
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    MaybeRegisterEventHooks() {
+  if (mGlobalEventHooks.empty()) {
+    RegisterEventHooks();
+  }
+}
+
+// static
+void CALLBACK
+WinWindowOcclusionTracker::WindowOcclusionCalculator::EventHookCallback(
+    HWINEVENTHOOK aWinEventHook, DWORD aEvent, HWND aHwnd, LONG aIdObject,
+    LONG aIdChild, DWORD aEventThread, DWORD aMsEventTime) {
+  if (sCalculator) {
+    sCalculator->ProcessEventHookCallback(aWinEventHook, aEvent, aHwnd,
+                                          aIdObject, aIdChild);
+  }
+}
+
+// static
+BOOL CALLBACK WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    ComputeNativeWindowOcclusionStatusCallback(HWND aHwnd, LPARAM aLParam) {
+  if (sCalculator) {
+    return sCalculator->ProcessComputeNativeWindowOcclusionStatusCallback(
+        aHwnd, reinterpret_cast<std::unordered_set<DWORD>*>(aLParam));
+  }
+  return FALSE;
+}
+
+// static
+BOOL CALLBACK WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    UpdateVisibleWindowProcessIdsCallback(HWND aHwnd, LPARAM aLParam) {
+  if (sCalculator) {
+    sCalculator->ProcessUpdateVisibleWindowProcessIdsCallback(aHwnd);
+    return TRUE;
+  }
+  return FALSE;
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    UpdateVisibleWindowProcessIds() {
+  mPidsForLocationChangeHook.clear();
+  ::EnumWindows(&UpdateVisibleWindowProcessIdsCallback, 0);
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    ComputeNativeWindowOcclusionStatus() {
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+  MOZ_ASSERT(mSerializedTaskDispatcher->IsOnCurrentThread());
+
+  if (mOcclusionUpdateRunnable) {
+    mOcclusionUpdateRunnable = nullptr;
+  }
+
+  if (mRootWindowHwndsOcclusionState.empty()) {
+    return;
+  }
+
+  // Set up initial conditions for occlusion calculation.
+  bool shouldUnregisterEventHooks = true;
+
+  // Compute the LayoutDeviceIntRegion for the screen.
+  int screenLeft = ::GetSystemMetrics(SM_XVIRTUALSCREEN);
+  int screenTop = ::GetSystemMetrics(SM_YVIRTUALSCREEN);
+  int screenWidth = ::GetSystemMetrics(SM_CXVIRTUALSCREEN);
+  int screenHeight = ::GetSystemMetrics(SM_CYVIRTUALSCREEN);
+  LayoutDeviceIntRegion screenRegion =
+      LayoutDeviceIntRect(screenLeft, screenTop, screenWidth, screenHeight);
+  mNumRootWindowsWithUnknownOcclusionState = 0;
+
+  CALC_LOG(LogLevel::Debug,
+           "ComputeNativeWindowOcclusionStatus() screen(%d, %d, %d, %d)",
+           screenLeft, screenTop, screenWidth, screenHeight);
+
+  for (auto& [hwnd, state] : mRootWindowHwndsOcclusionState) {
+    // IsIconic() checks for a minimized window. Immediately set the state of
+    // minimized windows to HIDDEN.
+    if (::IsIconic(hwnd)) {
+      state = OcclusionState::HIDDEN;
+    } else if (IsWindowOnCurrentVirtualDesktop(hwnd) == Some(false)) {
+      // If window is not on the current virtual desktop, immediately
+      // set the state of the window to OCCLUDED.
+      state = OcclusionState::OCCLUDED;
+      // Don't unregister event hooks when not on current desktop. There's no
+      // notification when that changes, so we can't reregister event hooks.
+      shouldUnregisterEventHooks = false;
+    } else {
+      state = OcclusionState::UNKNOWN;
+      shouldUnregisterEventHooks = false;
+      mNumRootWindowsWithUnknownOcclusionState++;
+    }
+  }
+
+  // Unregister event hooks if all native windows are minimized.
+  if (shouldUnregisterEventHooks) {
+    UnregisterEventHooks();
+  } else {
+    std::unordered_set<DWORD> currentPidsWithVisibleWindows;
+    mUnoccludedDesktopRegion = screenRegion;
+    // Calculate unoccluded region if there is a non-minimized native window.
+    // Also compute |current_pids_with_visible_windows| as we enumerate
+    // the windows.
+    EnumWindows(&ComputeNativeWindowOcclusionStatusCallback,
+                reinterpret_cast<LPARAM>(&currentPidsWithVisibleWindows));
+    // Check if mPidsForLocationChangeHook has any pids of processes
+    // currently without visible windows. If so, unhook the win event,
+    // remove the pid from mPidsForLocationChangeHook and remove
+    // the corresponding event hook from mProcessEventHooks.
+    std::unordered_set<DWORD> pidsToRemove;
+    for (auto locChangePid : mPidsForLocationChangeHook) {
+      if (currentPidsWithVisibleWindows.find(locChangePid) ==
+          currentPidsWithVisibleWindows.end()) {
+        // Remove the event hook from our map, and unregister the event hook.
+        // It's possible the eventhook will no longer be valid, but if we don't
+        // unregister the event hook, a process that toggles between having
+        // visible windows and not having visible windows could cause duplicate
+        // event hooks to get registered for the process.
+        UnhookWinEvent(mProcessEventHooks[locChangePid]);
+        mProcessEventHooks.erase(locChangePid);
+        pidsToRemove.insert(locChangePid);
+      }
+    }
+    if (!pidsToRemove.empty()) {
+      // XXX simplify
+      for (auto it = mPidsForLocationChangeHook.begin();
+           it != mPidsForLocationChangeHook.end();) {
+        if (pidsToRemove.find(*it) != pidsToRemove.end()) {
+          it = mPidsForLocationChangeHook.erase(it);
+        } else {
+          ++it;
+        }
+      }
+    }
+  }
+
+  std::unordered_map<HWND, OcclusionState>* map =
+      &mRootWindowHwndsOcclusionState;
+  bool showAllWindows = mShowingThumbnails;
+  RefPtr<Runnable> runnable = NS_NewRunnableFunction(
+      "CallUpdateOcclusionState", [map, showAllWindows]() {
+        WinWindowOcclusionTracker::CallUpdateOcclusionState(map,
+                                                            showAllWindows);
+      });
+  mSerializedTaskDispatcher->PostTaskToMain(runnable.forget());
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    ScheduleOcclusionCalculationIfNeeded() {
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+
+  // OcclusionUpdateRunnable is already queued.
+  if (mOcclusionUpdateRunnable) {
+    return;
+  }
+
+  CALC_LOG(LogLevel::Debug, "ScheduleOcclusionCalculationIfNeeded()");
+
+  RefPtr<CancelableRunnable> task = new OcclusionUpdateRunnable(this);
+  mOcclusionUpdateRunnable = task;
+  mSerializedTaskDispatcher->PostDelayedTaskToCalculator(
+      task.forget(), kOcclusionUpdateRunnableDelayMs);
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    RegisterGlobalEventHook(DWORD aEventMin, DWORD aEventMax) {
+  HWINEVENTHOOK eventHook =
+      ::SetWinEventHook(aEventMin, aEventMax, nullptr, &EventHookCallback, 0, 0,
+                        WINEVENT_OUTOFCONTEXT);
+  mGlobalEventHooks.push_back(eventHook);
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    RegisterEventHookForProcess(DWORD aPid) {
+  mPidsForLocationChangeHook.insert(aPid);
+  mProcessEventHooks[aPid] = SetWinEventHook(
+      EVENT_OBJECT_LOCATIONCHANGE, EVENT_OBJECT_LOCATIONCHANGE, nullptr,
+      &EventHookCallback, aPid, 0, WINEVENT_OUTOFCONTEXT);
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    RegisterEventHooks() {
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+  MOZ_RELEASE_ASSERT(mGlobalEventHooks.empty());
+  CALC_LOG(LogLevel::Info, "RegisterEventHooks()");
+
+  // Detects native window lost mouse capture
+  RegisterGlobalEventHook(EVENT_SYSTEM_CAPTUREEND, EVENT_SYSTEM_CAPTUREEND);
+
+  // Detects native window move (drag) and resizing events.
+  RegisterGlobalEventHook(EVENT_SYSTEM_MOVESIZESTART, EVENT_SYSTEM_MOVESIZEEND);
+
+  // Detects native window minimize and restore from taskbar events.
+  RegisterGlobalEventHook(EVENT_SYSTEM_MINIMIZESTART, EVENT_SYSTEM_MINIMIZEEND);
+
+  // Detects foreground window changing.
+  RegisterGlobalEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND);
+
+  // Detects objects getting shown and hidden. Used to know when the task bar
+  // and alt tab are showing preview windows so we can unocclude windows.
+  RegisterGlobalEventHook(EVENT_OBJECT_SHOW, EVENT_OBJECT_HIDE);
+
+  // Detects object state changes, e.g., enable/disable state, native window
+  // maximize and native window restore events.
+  RegisterGlobalEventHook(EVENT_OBJECT_STATECHANGE, EVENT_OBJECT_STATECHANGE);
+
+  // Cloaking and uncloaking of windows should trigger an occlusion calculation.
+  // In particular, switching virtual desktops seems to generate these events.
+  RegisterGlobalEventHook(EVENT_OBJECT_CLOAKED, EVENT_OBJECT_UNCLOAKED);
+
+  // Determine which subset of processes to set EVENT_OBJECT_LOCATIONCHANGE on
+  // because otherwise event throughput is very high, as it generates events
+  // for location changes of all objects, including the mouse moving on top of a
+  // window.
+  UpdateVisibleWindowProcessIds();
+  for (DWORD pid : mPidsForLocationChangeHook) {
+    RegisterEventHookForProcess(pid);
+  }
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    UnregisterEventHooks() {
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+  CALC_LOG(LogLevel::Info, "UnregisterEventHooks()");
+
+  for (const auto eventHook : mGlobalEventHooks) {
+    ::UnhookWinEvent(eventHook);
+  }
+  mGlobalEventHooks.clear();
+
+  for (const auto& [pid, eventHook] : mProcessEventHooks) {
+    ::UnhookWinEvent(eventHook);
+  }
+  mProcessEventHooks.clear();
+
+  mPidsForLocationChangeHook.clear();
+}
+
+bool WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    ProcessComputeNativeWindowOcclusionStatusCallback(
+        HWND aHwnd, std::unordered_set<DWORD>* aCurrentPidsWithVisibleWindows) {
+  LayoutDeviceIntRegion currUnoccludedDestkop = mUnoccludedDesktopRegion;
+  LayoutDeviceIntRect windowRect;
+  bool windowIsOccluding =
+      WindowCanOccludeOtherWindowsOnCurrentVirtualDesktop(aHwnd, &windowRect);
+  if (windowIsOccluding) {
+    // Hook this window's process with EVENT_OBJECT_LOCATION_CHANGE, if we are
+    // not already doing so.
+    DWORD pid;
+    ::GetWindowThreadProcessId(aHwnd, &pid);
+    aCurrentPidsWithVisibleWindows->insert(pid);
+    auto it = mProcessEventHooks.find(pid);
+    if (it == mProcessEventHooks.end()) {
+      RegisterEventHookForProcess(pid);
+    }
+
+    // If no more root windows to consider, return true so we can continue
+    // looking for windows we haven't hooked.
+    if (mNumRootWindowsWithUnknownOcclusionState == 0) {
+      return true;
+    }
+
+    mUnoccludedDesktopRegion.SubOut(windowRect);
+  } else if (mNumRootWindowsWithUnknownOcclusionState == 0) {
+    // This window can't occlude other windows, but we've determined the
+    // occlusion state of all root windows, so we can return.
+    return true;
+  }
+
+  // Ignore moving windows when deciding if windows under it are occluded.
+  if (aHwnd == mMovingWindow) {
+    return true;
+  }
+
+  // Check if |hwnd| is a root window; if so, we're done figuring out
+  // if it's occluded because we've seen all the windows "over" it.
+  auto it = mRootWindowHwndsOcclusionState.find(aHwnd);
+  if (it == mRootWindowHwndsOcclusionState.end() ||
+      it->second != OcclusionState::UNKNOWN) {
+    return true;
+  }
+
+  CALC_LOG(LogLevel::Debug,
+           "ProcessComputeNativeWindowOcclusionStatusCallback() windowRect(%d, "
+           "%d, %d, %d) IsOccluding %d",
+           windowRect.x, windowRect.y, windowRect.width, windowRect.height,
+           windowIsOccluding);
+
+  // On Win7, default theme makes root windows have complex regions by
+  // default. But we can still check if their bounding rect is occluded.
+  if (!windowIsOccluding) {
+    RECT rect;
+    if (::GetWindowRect(aHwnd, &rect) != 0) {
+      LayoutDeviceIntRect windowRect(
+          rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top);
+      currUnoccludedDestkop.SubOut(windowRect);
+    }
+  }
+
+  it->second = (mUnoccludedDesktopRegion == currUnoccludedDestkop)
+                   ? OcclusionState::OCCLUDED
+                   : OcclusionState::VISIBLE;
+  mNumRootWindowsWithUnknownOcclusionState--;
+
+  return true;
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    ProcessEventHookCallback(HWINEVENTHOOK aWinEventHook, DWORD aEvent,
+                             HWND aHwnd, LONG aIdObject, LONG aIdChild) {
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+
+  // No need to calculate occlusion if a zero HWND generated the event. This
+  // happens if there is no window associated with the event, e.g., mouse move
+  // events.
+  if (!aHwnd) {
+    return;
+  }
+
+  // We only care about events for window objects. In particular, we don't care
+  // about OBJID_CARET, which is spammy.
+  if (aIdObject != OBJID_WINDOW) {
+    return;
+  }
+
+  CALC_LOG(LogLevel::Debug,
+           "WindowOcclusionCalculator::ProcessEventHookCallback() aEvent 0x%lx",
+           aEvent);
+
+  // We generally ignore events for popup windows, except for when the taskbar
+  // is hidden or Windows Taskbar, in which case we recalculate occlusion.
+  // XXX Chrome Widget popup handling is removed for now.
+  bool calculateOcclusion = true;
+  if (::GetWindowLong(aHwnd, GWL_STYLE) & WS_POPUP) {
+    nsAutoString className;
+    if (WinUtils::GetClassName(aHwnd, className)) {
+      calculateOcclusion = className.Equals(L"Shell_TrayWnd");
+    }
+  }
+
+  // Detect if either the alt tab view or the task list thumbnail is being
+  // shown. If so, mark all non-hidden windows as occluded, and remember that
+  // we're in the showing_thumbnails state. This lasts until we get told that
+  // either the alt tab view or task list thumbnail are hidden.
+  if (aEvent == EVENT_OBJECT_SHOW) {
+    // Avoid getting the aHwnd's class name, and recomputing occlusion, if not
+    // needed.
+    if (mShowingThumbnails) {
+      return;
+    }
+    nsAutoString className;
+    if (WinUtils::GetClassName(aHwnd, className)) {
+      const auto name = NS_ConvertUTF16toUTF8(className);
+      CALC_LOG(LogLevel::Debug,
+               "ProcessEventHookCallback() EVENT_OBJECT_SHOW %s", name.get());
+
+      if (name.Equals("MultitaskingViewFrame") ||
+          name.Equals("TaskListThumbnailWnd")) {
+        CALC_LOG(LogLevel::Info,
+                 "ProcessEventHookCallback() mShowingThumbnails = true");
+        mShowingThumbnails = true;
+
+        std::unordered_map<HWND, OcclusionState>* map =
+            &mRootWindowHwndsOcclusionState;
+        bool showAllWindows = mShowingThumbnails;
+        RefPtr<Runnable> runnable = NS_NewRunnableFunction(
+            "CallUpdateOcclusionState", [map, showAllWindows]() {
+              WinWindowOcclusionTracker::CallUpdateOcclusionState(
+                  map, showAllWindows);
+            });
+        mSerializedTaskDispatcher->PostTaskToMain(runnable.forget());
+      }
+    }
+    return;
+  } else if (aEvent == EVENT_OBJECT_HIDE) {
+    // Avoid getting the aHwnd's class name, and recomputing occlusion, if not
+    // needed.
+    if (!mShowingThumbnails) {
+      return;
+    }
+    nsAutoString className;
+    WinUtils::GetClassName(aHwnd, className);
+    const auto name = NS_ConvertUTF16toUTF8(className);
+    CALC_LOG(LogLevel::Debug, "ProcessEventHookCallback() EVENT_OBJECT_HIDE %s",
+             name.get());
+    if (name.Equals("MultitaskingViewFrame") ||
+        name.Equals("TaskListThumbnailWnd")) {
+      CALC_LOG(LogLevel::Info,
+               "ProcessEventHookCallback() mShowingThumbnails = false");
+      mShowingThumbnails = false;
+      // Let occlusion calculation fix occlusion state, even though hwnd might
+      // be a popup window.
+      calculateOcclusion = true;
+    } else {
+      return;
+    }
+  }
+  // Don't continually calculate occlusion while a window is moving (unless it's
+  // a root window), but instead once at the beginning and once at the end.
+  // Remember the window being moved so if it's a root window, we can ignore
+  // it when deciding if windows under it are occluded.
+  else if (aEvent == EVENT_SYSTEM_MOVESIZESTART) {
+    mMovingWindow = aHwnd;
+  } else if (aEvent == EVENT_SYSTEM_MOVESIZEEND) {
+    mMovingWindow = 0;
+  } else if (mMovingWindow != 0) {
+    if (aEvent == EVENT_OBJECT_LOCATIONCHANGE ||
+        aEvent == EVENT_OBJECT_STATECHANGE) {
+      // Ignore move events if it's not a root window that's being moved. If it
+      // is a root window, we want to calculate occlusion to support tab
+      // dragging to windows that were occluded when the drag was started but
+      // are no longer occluded.
+      if (mRootWindowHwndsOcclusionState.find(aHwnd) ==
+          mRootWindowHwndsOcclusionState.end()) {
+        return;
+      }
+    } else {
+      // If we get an event that isn't a location/state change, then we probably
+      // missed the movesizeend notification, or got events out of order. In
+      // that case, we want to go back to normal occlusion calculation.
+      mMovingWindow = 0;
+    }
+  }
+
+  if (!calculateOcclusion) {
+    return;
+  }
+
+  ScheduleOcclusionCalculationIfNeeded();
+}
+
+void WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    ProcessUpdateVisibleWindowProcessIdsCallback(HWND aHwnd) {
+  MOZ_ASSERT(IsInWinWindowOcclusionThread());
+
+  LayoutDeviceIntRect windowRect;
+  if (WindowCanOccludeOtherWindowsOnCurrentVirtualDesktop(aHwnd, &windowRect)) {
+    DWORD pid;
+    ::GetWindowThreadProcessId(aHwnd, &pid);
+    mPidsForLocationChangeHook.insert(pid);
+  }
+}
+
+bool WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    WindowCanOccludeOtherWindowsOnCurrentVirtualDesktop(
+        HWND aHwnd, LayoutDeviceIntRect* aWindowRect) {
+  return IsWindowVisibleAndFullyOpaque(aHwnd, aWindowRect) &&
+         (IsWindowOnCurrentVirtualDesktop(aHwnd) == Some(true));
+}
+
+Maybe<bool> WinWindowOcclusionTracker::WindowOcclusionCalculator::
+    IsWindowOnCurrentVirtualDesktop(HWND aHwnd) {
+  if (!mVirtualDesktopManager) {
+    return Some(true);
+  }
+
+  BOOL onCurrentDesktop;
+  HRESULT hr = mVirtualDesktopManager->IsWindowOnCurrentVirtualDesktop(
+      aHwnd, &onCurrentDesktop);
+  if (FAILED(hr)) {
+    // In this case, we do not know the window is in which virtual desktop.
+    return Nothing();
+  }
+
+  if (onCurrentDesktop) {
+    return Some(true);
+  }
+
+  GUID workspaceGuid;
+  hr = mVirtualDesktopManager->GetWindowDesktopId(aHwnd, &workspaceGuid);
+  if (FAILED(hr)) {
+    // In this case, we do not know the window is in which virtual desktop.
+    return Nothing();
+  }
+
+  // IsWindowOnCurrentVirtualDesktop() is flaky for newly opened windows,
+  // which causes test flakiness. Occasionally, it incorrectly says a window
+  // is not on the current virtual desktop when it is. In this situation,
+  // it also returns GUID_NULL for the desktop id.
+  if (workspaceGuid == GUID_NULL) {
+    // In this case, we do not know if the window is in which virtual desktop.
+    // But we hanle it as on current virtual desktop.
+    // It does not cause a problem to window occlusion.
+    // Since if window is not on current virtual desktop, window size becomes
+    // (0, 0, 0, 0). It makes window occlusion handling explicit. It is
+    // necessary for gtest.
+    return Some(true);
+  }
+
+  return Some(false);
+}
+
+#undef LOG
+#undef CALC_LOG
+
+}  // namespace mozilla::widget
diff --git a/widget/windows/WinWindowOcclusionTracker.h b/widget/windows/WinWindowOcclusionTracker.h
new file mode 100644
index 0000000000..b82a41b984
--- /dev/null
+++ b/widget/windows/WinWindowOcclusionTracker.h
@@ -0,0 +1,333 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_WinWindowOcclusionTracker_h
+#define widget_windows_WinWindowOcclusionTracker_h
+
+#include <string>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+
+#include "nsIWeakReferenceUtils.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/WindowsVersion.h"
+#include "mozilla/ThreadSafeWeakPtr.h"
+#include "mozilla/widget/WindowOcclusionState.h"
+#include "mozilla/widget/WinEventObserver.h"
+#include "Units.h"
+#include "nsThreadUtils.h"
+
+class nsBaseWidget;
+struct IVirtualDesktopManager;
+class WinWindowOcclusionTrackerTest;
+class WinWindowOcclusionTrackerInteractiveTest;
+
+namespace base {
+class Thread;
+}  // namespace base
+
+namespace mozilla {
+
+namespace widget {
+
+class OcclusionUpdateRunnable;
+class SerializedTaskDispatcher;
+class UpdateOcclusionStateRunnable;
+
+// This class handles window occlusion tracking by using HWND.
+// Implementation is borrowed from chromium's NativeWindowOcclusionTrackerWin.
+class WinWindowOcclusionTracker final : public DisplayStatusListener,
+                                        public SessionChangeListener {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WinWindowOcclusionTracker)
+
+  /// Can only be called from the main thread.
+  static WinWindowOcclusionTracker* Get();
+
+  /// Can only be called from the main thread.
+  static void Ensure();
+
+  /// Can only be called from the main thread.
+  static void ShutDown();
+
+  /// Can be called from any thread.
+  static MessageLoop* OcclusionCalculatorLoop();
+
+  /// Can be called from any thread.
+  static bool IsInWinWindowOcclusionThread();
+
+  /// Can only be called from the main thread.
+  void EnsureDisplayStatusObserver();
+
+  /// Can only be called from the main thread.
+  void EnsureSessionChangeObserver();
+
+  // Enables notifying to widget via NotifyOcclusionState() when the occlusion
+  // state has been computed.
+  void Enable(nsBaseWidget* aWindow, HWND aHwnd);
+
+  // Disables notifying to widget via NotifyOcclusionState() when the occlusion
+  // state has been computed.
+  void Disable(nsBaseWidget* aWindow, HWND aHwnd);
+
+  // Called when widget's visibility is changed
+  void OnWindowVisibilityChanged(nsBaseWidget* aWindow, bool aVisible);
+
+  SerializedTaskDispatcher* GetSerializedTaskDispatcher() {
+    return mSerializedTaskDispatcher;
+  }
+
+  void TriggerCalculation();
+
+  void DumpOccludingWindows(HWND aHWnd);
+
+ private:
+  friend class ::WinWindowOcclusionTrackerTest;
+  friend class ::WinWindowOcclusionTrackerInteractiveTest;
+
+  explicit WinWindowOcclusionTracker(UniquePtr<base::Thread> aThread);
+  virtual ~WinWindowOcclusionTracker();
+
+  // This class computes the occlusion state of the tracked windows.
+  // It runs on a separate thread, and notifies the main thread of
+  // the occlusion state of the tracked windows.
+  class WindowOcclusionCalculator {
+    NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WindowOcclusionCalculator)
+   public:
+    // Creates WindowOcclusionCalculator instance.
+    static void CreateInstance();
+
+    // Clear WindowOcclusionCalculator instance.
+    static void ClearInstance();
+
+    // Returns existing WindowOcclusionCalculator instance.
+    static WindowOcclusionCalculator* GetInstance() { return sCalculator; }
+
+    void Initialize();
+    void Shutdown();
+
+    void EnableOcclusionTrackingForWindow(HWND hwnd);
+    void DisableOcclusionTrackingForWindow(HWND hwnd);
+
+    // If a window becomes visible, makes sure event hooks are registered.
+    void HandleVisibilityChanged(bool aVisible);
+
+    void HandleTriggerCalculation();
+
+   private:
+    WindowOcclusionCalculator();
+    ~WindowOcclusionCalculator();
+
+    // Registers event hooks, if not registered.
+    void MaybeRegisterEventHooks();
+
+    // This is the callback registered to get notified of various Windows
+    // events, like window moving/resizing.
+    static void CALLBACK EventHookCallback(HWINEVENTHOOK aWinEventHook,
+                                           DWORD aEvent, HWND aHwnd,
+                                           LONG aIdObject, LONG aIdChild,
+                                           DWORD aEventThread,
+                                           DWORD aMsEventTime);
+
+    // EnumWindows callback used to iterate over all hwnds to determine
+    // occlusion status of all tracked root windows.  Also builds up
+    // |current_pids_with_visible_windows_| and registers event hooks for newly
+    // discovered processes with visible hwnds.
+    static BOOL CALLBACK
+    ComputeNativeWindowOcclusionStatusCallback(HWND hwnd, LPARAM lParam);
+
+    // EnumWindows callback used to update the list of process ids with
+    // visible hwnds, |pids_for_location_change_hook_|.
+    static BOOL CALLBACK UpdateVisibleWindowProcessIdsCallback(HWND aHwnd,
+                                                               LPARAM aLParam);
+
+    // Determines which processes owning visible application windows to set the
+    // EVENT_OBJECT_LOCATIONCHANGE event hook for and stores the pids in
+    // |pids_for_location_change_hook_|.
+    void UpdateVisibleWindowProcessIds();
+
+    // Computes the native window occlusion status for all tracked root gecko
+    // windows in |root_window_hwnds_occlusion_state_| and notifies them if
+    // their occlusion status has changed.
+    void ComputeNativeWindowOcclusionStatus();
+
+    // Schedules an occlusion calculation , if one isn't already scheduled.
+    void ScheduleOcclusionCalculationIfNeeded();
+
+    // Registers a global event hook (not per process) for the events in the
+    // range from |event_min| to |event_max|, inclusive.
+    void RegisterGlobalEventHook(DWORD aEventMin, DWORD aEventMax);
+
+    // Registers the EVENT_OBJECT_LOCATIONCHANGE event hook for the process with
+    // passed id. The process has one or more visible, opaque windows.
+    void RegisterEventHookForProcess(DWORD aPid);
+
+    // Registers/Unregisters the event hooks necessary for occlusion tracking
+    // via calls to RegisterEventHook. These event hooks are disabled when all
+    // tracked windows are minimized.
+    void RegisterEventHooks();
+    void UnregisterEventHooks();
+
+    // EnumWindows callback for occlusion calculation. Returns true to
+    // continue enumeration, false otherwise. Currently, always returns
+    // true because this function also updates currentPidsWithVisibleWindows,
+    // and needs to see all HWNDs.
+    bool ProcessComputeNativeWindowOcclusionStatusCallback(
+        HWND aHwnd, std::unordered_set<DWORD>* aCurrentPidsWithVisibleWindows);
+
+    // Processes events sent to OcclusionEventHookCallback.
+    // It generally triggers scheduling of the occlusion calculation, but
+    // ignores certain events in order to not calculate occlusion more than
+    // necessary.
+    void ProcessEventHookCallback(HWINEVENTHOOK aWinEventHook, DWORD aEvent,
+                                  HWND aHwnd, LONG aIdObject, LONG aIdChild);
+
+    // EnumWindows callback for determining which processes to set the
+    // EVENT_OBJECT_LOCATIONCHANGE event hook for. We set that event hook for
+    // processes hosting fully visible, opaque windows.
+    void ProcessUpdateVisibleWindowProcessIdsCallback(HWND aHwnd);
+
+    // Returns true if the window is visible, fully opaque, and on the current
+    // virtual desktop, false otherwise.
+    bool WindowCanOccludeOtherWindowsOnCurrentVirtualDesktop(
+        HWND aHwnd, LayoutDeviceIntRect* aWindowRect);
+
+    // Returns true if aHwnd is definitely on the current virtual desktop,
+    // false if it's definitely not on the current virtual desktop, and Nothing
+    // if we we can't tell for sure.
+    Maybe<bool> IsWindowOnCurrentVirtualDesktop(HWND aHwnd);
+
+    static StaticRefPtr<WindowOcclusionCalculator> sCalculator;
+
+    // Map of root app window hwnds and their occlusion state. This contains
+    // both visible and hidden windows.
+    // It is accessed from WinWindowOcclusionTracker::UpdateOcclusionState()
+    // without using mutex. The access is safe by using
+    // SerializedTaskDispatcher.
+    std::unordered_map<HWND, OcclusionState> mRootWindowHwndsOcclusionState;
+
+    // Values returned by SetWinEventHook are stored so that hooks can be
+    // unregistered when necessary.
+    std::vector<HWINEVENTHOOK> mGlobalEventHooks;
+
+    // Map from process id to EVENT_OBJECT_LOCATIONCHANGE event hook.
+    std::unordered_map<DWORD, HWINEVENTHOOK> mProcessEventHooks;
+
+    // Pids of processes for which the EVENT_OBJECT_LOCATIONCHANGE event hook is
+    // set.
+    std::unordered_set<DWORD> mPidsForLocationChangeHook;
+
+    // Used as a timer to delay occlusion update.
+    RefPtr<CancelableRunnable> mOcclusionUpdateRunnable;
+
+    // Used to determine if a window is occluded. As we iterate through the
+    // hwnds in z-order, we subtract each opaque window's rect from
+    // mUnoccludedDesktopRegion. When we get to a root window, we subtract
+    // it from mUnoccludedDesktopRegion, and if mUnoccludedDesktopRegion
+    // doesn't change, the root window was already occluded.
+    LayoutDeviceIntRegion mUnoccludedDesktopRegion;
+
+    // Keeps track of how many root windows we need to compute the occlusion
+    // state of in a call to ComputeNativeWindowOcclusionStatus. Once we've
+    // determined the state of all root windows, we can stop subtracting
+    // windows from mUnoccludedDesktopRegion;.
+    int mNumRootWindowsWithUnknownOcclusionState;
+
+    // This is true if the task bar thumbnails or the alt tab thumbnails are
+    // showing.
+    bool mShowingThumbnails = false;
+
+    // Used to keep track of the window that's currently moving. That window
+    // is ignored for calculation occlusion so that tab dragging won't
+    // ignore windows occluded by the dragged window.
+    HWND mMovingWindow = 0;
+
+    // Only used on Win10+.
+    RefPtr<IVirtualDesktopManager> mVirtualDesktopManager;
+
+    // Used to serialize tasks related to mRootWindowHwndsOcclusionState.
+    RefPtr<SerializedTaskDispatcher> mSerializedTaskDispatcher;
+
+    // This is an alias to the singleton WinWindowOcclusionTracker mMonitor,
+    // and is used in ShutDown().
+    Monitor& mMonitor;
+
+    friend class OcclusionUpdateRunnable;
+  };
+
+  static BOOL CALLBACK DumpOccludingWindowsCallback(HWND aHWnd, LPARAM aLParam);
+
+  // Returns true if we are interested in |hwnd| for purposes of occlusion
+  // calculation. We are interested in |hwnd| if it is a window that is
+  // visible, opaque, bounded, and not a popup or floating window. If we are
+  // interested in |hwnd|, stores the window rectangle in |window_rect|.
+  static bool IsWindowVisibleAndFullyOpaque(HWND aHwnd,
+                                            LayoutDeviceIntRect* aWindowRect);
+
+  void Destroy();
+
+  static void CallUpdateOcclusionState(
+      std::unordered_map<HWND, OcclusionState>* aMap, bool aShowAllWindows);
+
+  // Updates root windows occclusion state. If aShowAllWindows is true,
+  // all non-hidden windows will be marked visible.  This is used to force
+  // rendering of thumbnails.
+  void UpdateOcclusionState(std::unordered_map<HWND, OcclusionState>* aMap,
+                            bool aShowAllWindows);
+
+  // This is called with session changed notifications. If the screen is locked
+  // by the current session, it marks app windows as occluded.
+  void OnSessionChange(WPARAM aStatusCode,
+                       Maybe<bool> aIsCurrentSession) override;
+
+  // This is called when the display is put to sleep. If the display is sleeping
+  // it marks app windows as occluded.
+  void OnDisplayStateChanged(bool aDisplayOn) override;
+
+  // Marks all root windows as either occluded, or if hwnd IsIconic, hidden.
+  void MarkNonIconicWindowsOccluded();
+
+  static StaticRefPtr<WinWindowOcclusionTracker> sTracker;
+
+  // "WinWindowOcclusionCalc" thread.
+  UniquePtr<base::Thread> mThread;
+  Monitor mMonitor;
+
+  // Has ShutDown been called on us? We might have survived if our thread join
+  // timed out.
+  bool mHasAttemptedShutdown = false;
+
+  // Map of HWND to widget. Maintained on main thread, and used to send
+  // occlusion state notifications to Windows from
+  // mRootWindowHwndsOcclusionState.
+  std::unordered_map<HWND, nsWeakPtr> mHwndRootWindowMap;
+
+  // This is set by UpdateOcclusionState(). It is currently only used by tests.
+  int mNumVisibleRootWindows = 0;
+
+  // If the screen is locked, windows are considered occluded.
+  bool mScreenLocked = false;
+
+  // If the display is off, windows are considered occluded.
+  bool mDisplayOn = true;
+
+  RefPtr<DisplayStatusObserver> mDisplayStatusObserver;
+
+  RefPtr<SessionChangeObserver> mSessionChangeObserver;
+
+  // Used to serialize tasks related to mRootWindowHwndsOcclusionState.
+  RefPtr<SerializedTaskDispatcher> mSerializedTaskDispatcher;
+
+  friend class OcclusionUpdateRunnable;
+  friend class UpdateOcclusionStateRunnable;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // widget_windows_WinWindowOcclusionTracker_h
diff --git a/widget/windows/WindowHook.cpp b/widget/windows/WindowHook.cpp
new file mode 100644
index 0000000000..06773f21b7
--- /dev/null
+++ b/widget/windows/WindowHook.cpp
@@ -0,0 +1,113 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WindowHook.h"
+#include "nsWindow.h"
+#include "nsWindowDefs.h"
+
+namespace mozilla {
+namespace widget {
+
+nsresult WindowHook::AddHook(UINT nMsg, Callback callback, void* context) {
+  MessageData* data = LookupOrCreate(nMsg);
+
+  if (!data) return NS_ERROR_OUT_OF_MEMORY;
+
+  // Ensure we don't overwrite another hook
+  NS_ENSURE_TRUE(nullptr == data->hook.cb, NS_ERROR_UNEXPECTED);
+
+  data->hook = CallbackData(callback, context);
+
+  return NS_OK;
+}
+
+nsresult WindowHook::RemoveHook(UINT nMsg, Callback callback, void* context) {
+  CallbackData cbdata(callback, context);
+  MessageData* data = Lookup(nMsg);
+  if (!data) return NS_ERROR_UNEXPECTED;
+  if (data->hook != cbdata) return NS_ERROR_UNEXPECTED;
+  data->hook = CallbackData();
+
+  DeleteIfEmpty(data);
+  return NS_OK;
+}
+
+nsresult WindowHook::AddMonitor(UINT nMsg, Callback callback, void* context) {
+  MessageData* data = LookupOrCreate(nMsg);
+  return (data && data->monitors.AppendElement(CallbackData(callback, context),
+                                               fallible))
+             ? NS_OK
+             : NS_ERROR_OUT_OF_MEMORY;
+}
+
+nsresult WindowHook::RemoveMonitor(UINT nMsg, Callback callback,
+                                   void* context) {
+  CallbackData cbdata(callback, context);
+  MessageData* data = Lookup(nMsg);
+  if (!data) return NS_ERROR_UNEXPECTED;
+  CallbackDataArray::index_type idx = data->monitors.IndexOf(cbdata);
+  if (idx == CallbackDataArray::NoIndex) return NS_ERROR_UNEXPECTED;
+  data->monitors.RemoveElementAt(idx);
+  DeleteIfEmpty(data);
+  return NS_OK;
+}
+
+WindowHook::MessageData* WindowHook::Lookup(UINT nMsg) {
+  MessageDataArray::index_type idx;
+  for (idx = 0; idx < mMessageData.Length(); idx++) {
+    MessageData& data = mMessageData[idx];
+    if (data.nMsg == nMsg) return &data;
+  }
+  return nullptr;
+}
+
+WindowHook::MessageData* WindowHook::LookupOrCreate(UINT nMsg) {
+  MessageData* data = Lookup(nMsg);
+  if (!data) {
+    data = mMessageData.AppendElement();
+
+    if (!data) return nullptr;
+
+    data->nMsg = nMsg;
+  }
+  return data;
+}
+
+void WindowHook::DeleteIfEmpty(MessageData* data) {
+  // Never remove a MessageData that has still a hook or monitor entries.
+  if (data->hook || !data->monitors.IsEmpty()) return;
+
+  MessageDataArray::index_type idx;
+  idx = data - mMessageData.Elements();
+  NS_ASSERTION(
+      idx < mMessageData.Length(),
+      "Attempted to delete MessageData that doesn't belong to this array!");
+  mMessageData.RemoveElementAt(idx);
+}
+
+bool WindowHook::Notify(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam,
+                        MSGResult& aResult) {
+  MessageData* data = Lookup(nMsg);
+  if (!data) return false;
+
+  uint32_t length = data->monitors.Length();
+  for (uint32_t midx = 0; midx < length; midx++) {
+    data->monitors[midx].Invoke(hWnd, nMsg, wParam, lParam, &aResult.mResult);
+  }
+
+  aResult.mConsumed =
+      data->hook.Invoke(hWnd, nMsg, wParam, lParam, &aResult.mResult);
+  return aResult.mConsumed;
+}
+
+bool WindowHook::CallbackData::Invoke(HWND hWnd, UINT msg, WPARAM wParam,
+                                      LPARAM lParam, LRESULT* aResult) {
+  if (!cb) return false;
+  return cb(context, hWnd, msg, wParam, lParam, aResult);
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/WindowHook.h b/widget/windows/WindowHook.h
new file mode 100644
index 0000000000..1d1f4b02da
--- /dev/null
+++ b/widget/windows/WindowHook.h
@@ -0,0 +1,76 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __mozilla_WindowHook_h__
+#define __mozilla_WindowHook_h__
+
+#include <windows.h>
+
+#include <nsHashKeys.h>
+#include <nsClassHashtable.h>
+#include <nsTArray.h>
+
+#include "nsAppShell.h"
+
+class nsWindow;
+
+namespace mozilla {
+namespace widget {
+
+struct MSGResult;
+
+class WindowHook {
+ public:
+  // It is expected that most callbacks will return false
+  typedef bool (*Callback)(void* aContext, HWND hWnd, UINT nMsg, WPARAM wParam,
+                           LPARAM lParam, LRESULT* aResult);
+
+  nsresult AddHook(UINT nMsg, Callback callback, void* context);
+  nsresult RemoveHook(UINT nMsg, Callback callback, void* context);
+  nsresult AddMonitor(UINT nMsg, Callback callback, void* context);
+  nsresult RemoveMonitor(UINT nMsg, Callback callback, void* context);
+
+ private:
+  struct CallbackData {
+    Callback cb;
+    void* context;
+
+    CallbackData() : cb(nullptr), context(nullptr) {}
+    CallbackData(Callback cb, void* ctx) : cb(cb), context(ctx) {}
+    bool Invoke(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam,
+                LRESULT* aResult);
+    bool operator==(const CallbackData& rhs) const {
+      return cb == rhs.cb && context == rhs.context;
+    }
+    bool operator!=(const CallbackData& rhs) const { return !(*this == rhs); }
+    explicit operator bool() const { return !!cb; }
+  };
+
+  typedef nsTArray<CallbackData> CallbackDataArray;
+  struct MessageData {
+    UINT nMsg;
+    CallbackData hook;
+    CallbackDataArray monitors;
+  };
+
+  bool Notify(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam,
+              MSGResult& aResult);
+
+  MessageData* Lookup(UINT nMsg);
+  MessageData* LookupOrCreate(UINT nMsg);
+  void DeleteIfEmpty(MessageData* data);
+
+  typedef nsTArray<MessageData> MessageDataArray;
+  MessageDataArray mMessageData;
+
+  // For Notify
+  friend class ::nsWindow;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif  // __mozilla_WindowHook_h__
diff --git a/widget/windows/WindowsConsole.cpp b/widget/windows/WindowsConsole.cpp
new file mode 100644
index 0000000000..c8e7eb1a11
--- /dev/null
+++ b/widget/windows/WindowsConsole.cpp
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WindowsConsole.h"
+
+#include <windows.h>
+#include <fcntl.h>
+#include <cstdio>
+#include <io.h>
+
+namespace mozilla {
+
+static void AssignStdHandle(const char* aPath, const char* aMode, FILE* aStream,
+                            DWORD aStdHandle) {
+  // Visual Studio's _fileno() returns -2 for the standard
+  // streams if they aren't associated with an output stream.
+  const int fd = _fileno(aStream);
+  if (fd == -2) {
+    freopen(aPath, aMode, aStream);
+    return;
+  }
+  if (fd < 0) {
+    return;
+  }
+
+  const HANDLE handle = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
+  if (handle == INVALID_HANDLE_VALUE) {
+    return;
+  }
+
+  const HANDLE oldHandle = GetStdHandle(aStdHandle);
+  if (handle == oldHandle) {
+    return;
+  }
+
+  SetStdHandle(aStdHandle, handle);
+}
+
+// This code attaches the process to the appropriate console.
+void UseParentConsole() {
+  if (AttachConsole(ATTACH_PARENT_PROCESS)) {
+    // Redirect the standard streams to the existing console, but
+    // only if they haven't been redirected to a valid file.
+    AssignStdHandle("CONOUT$", "w", stdout, STD_OUTPUT_HANDLE);
+    // There is no CONERR$, so use CONOUT$ for stderr as well.
+    AssignStdHandle("CONOUT$", "w", stderr, STD_ERROR_HANDLE);
+    AssignStdHandle("CONIN$", "r", stdin, STD_INPUT_HANDLE);
+  }
+}
+
+}  // namespace mozilla
diff --git a/widget/windows/WindowsConsole.h b/widget/windows/WindowsConsole.h
new file mode 100644
index 0000000000..4b8ecf1823
--- /dev/null
+++ b/widget/windows/WindowsConsole.h
@@ -0,0 +1,16 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_WindowsConsole_h
+#define mozilla_WindowsConsole_h
+
+namespace mozilla {
+
+// This code attaches the process to the appropriate console.
+void UseParentConsole();
+
+}  // namespace mozilla
+
+#endif  // mozilla_WindowsConsole_h
diff --git a/widget/windows/WindowsEMF.cpp b/widget/windows/WindowsEMF.cpp
new file mode 100644
index 0000000000..71e3631bea
--- /dev/null
+++ b/widget/windows/WindowsEMF.cpp
@@ -0,0 +1,94 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WindowsEMF.h"
+
+namespace mozilla {
+namespace widget {
+
+WindowsEMF::WindowsEMF() : mEmf(nullptr), mDC(nullptr) {}
+
+WindowsEMF::~WindowsEMF() { ReleaseAllResource(); }
+
+bool WindowsEMF::InitForDrawing(const wchar_t* aMetafilePath /* = nullptr */) {
+  ReleaseAllResource();
+
+  mDC = ::CreateEnhMetaFile(nullptr, aMetafilePath, nullptr, nullptr);
+  return !!mDC;
+}
+
+bool WindowsEMF::InitFromFileContents(const wchar_t* aMetafilePath) {
+  MOZ_ASSERT(aMetafilePath);
+  ReleaseAllResource();
+
+  mEmf = ::GetEnhMetaFileW(aMetafilePath);
+  return !!mEmf;
+}
+
+bool WindowsEMF::InitFromFileContents(LPBYTE aBytes, UINT aSize) {
+  MOZ_ASSERT(aBytes && aSize != 0);
+  ReleaseAllResource();
+
+  mEmf = SetEnhMetaFileBits(aSize, aBytes);
+
+  return !!mEmf;
+}
+
+bool WindowsEMF::FinishDocument() {
+  if (mDC) {
+    mEmf = ::CloseEnhMetaFile(mDC);
+    mDC = nullptr;
+  }
+  return !!mEmf;
+}
+
+void WindowsEMF::ReleaseEMFHandle() {
+  if (mEmf) {
+    ::DeleteEnhMetaFile(mEmf);
+    mEmf = nullptr;
+  }
+}
+
+void WindowsEMF::ReleaseAllResource() {
+  FinishDocument();
+  ReleaseEMFHandle();
+}
+
+bool WindowsEMF::Playback(HDC aDeviceContext, const RECT& aRect) {
+  DebugOnly<bool> result = FinishDocument();
+  MOZ_ASSERT(result, "This function should be used after InitXXX.");
+
+  return ::PlayEnhMetaFile(aDeviceContext, mEmf, &aRect) != 0;
+}
+
+bool WindowsEMF::SaveToFile() {
+  DebugOnly<bool> result = FinishDocument();
+  MOZ_ASSERT(result, "This function should be used after InitXXX.");
+
+  ReleaseEMFHandle();
+  return true;
+}
+
+UINT WindowsEMF::GetEMFContentSize() {
+  DebugOnly<bool> result = FinishDocument();
+  MOZ_ASSERT(result, "This function should be used after InitXXX.");
+
+  return GetEnhMetaFileBits(mEmf, 0, NULL);
+}
+
+bool WindowsEMF::GetEMFContentBits(LPBYTE aBytes) {
+  DebugOnly<bool> result = FinishDocument();
+  MOZ_ASSERT(result, "This function should be used after InitXXX.");
+
+  UINT emfSize = GetEMFContentSize();
+  if (GetEnhMetaFileBits(mEmf, emfSize, aBytes) != emfSize) {
+    return false;
+  }
+
+  return true;
+}
+
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/WindowsEMF.h b/widget/windows/WindowsEMF.h
new file mode 100644
index 0000000000..3a7a20173c
--- /dev/null
+++ b/widget/windows/WindowsEMF.h
@@ -0,0 +1,106 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZILLA_WIDGET_WINDOWSEMF_H
+#define MOZILLA_WIDGET_WINDOWSEMF_H
+
+/* include windows.h for the HDC definitions that we need. */
+#include <windows.h>
+
+namespace mozilla {
+namespace widget {
+
+/**
+ * Windows Enhance Metafile: https://en.wikipedia.org/wiki/Windows_Metafile
+ * A metafile, also called a vector image, is an image that is stored as a
+ * sequence of drawing commands and settings. The commands and settings
+ * recorded in a Metafile object can be stored in memory or saved to a file.
+ *
+ * The metafile device context is used for all drawing operations required to
+ * create the picture. When the system processes a GDI function associated with
+ * a metafile DC, it converts the function into the appropriate data and stores
+ * this data in a record appended to the metafile.
+ */
+class WindowsEMF {
+ public:
+  WindowsEMF();
+  ~WindowsEMF();
+
+  /**
+   * Initializes the object with the path of a file where the EMF data stream
+   * should be stored. Callers are then expected to call GetDC() to draw output
+   * before going on to call Playback() or SaveToFile() to generate the EMF
+   * output.
+   */
+  bool InitForDrawing(const wchar_t* aMetafilePath = nullptr);
+
+  /**
+   * Initializes the object with an existing EMF file. Consumers cannot use
+   * GetDC() to obtain an HDC to modify the file. They can only use Playback().
+   */
+  bool InitFromFileContents(const wchar_t* aMetafilePath);
+
+  /**
+   * Creates the EMF from the specified data
+   *
+   * @param aByte Pointer to a buffer that contains EMF data.
+   * @param aSize Specifies the size, in bytes, of aByte.
+   */
+  bool InitFromFileContents(PBYTE aBytes, UINT aSize);
+
+  /**
+   * If this object was initiaziled using InitForDrawing() then this function
+   * returns an HDC that can be drawn to generate the EMF output. Otherwise it
+   * returns null. After finishing with the HDC, consumers could call Playback()
+   * to draw EMF onto the given DC or call SaveToFile() to finish writing the
+   * EMF file.
+   */
+  HDC GetDC() const {
+    MOZ_ASSERT(mDC,
+               "GetDC can be used only after "
+               "InitForDrawing/ InitFromFileContents and before"
+               "Playback/ SaveToFile");
+    return mDC;
+  }
+
+  /**
+   * Play the EMF's drawing commands onto the given DC.
+   */
+  bool Playback(HDC aDeviceContext, const RECT& aRect);
+
+  /**
+   * Called to generate the EMF file once a consumer has finished drawing to
+   * the HDC returned by GetDC(), if initializes the object with the path of a
+   * file.
+   */
+  bool SaveToFile();
+
+  /**
+   * Return the size of the enhanced metafile, in bytes.
+   */
+  UINT GetEMFContentSize();
+
+  /**
+   * Retrieves the contents of the EMF and copies them into a buffer.
+   *
+   * @param aByte the buffer to receive the data.
+   */
+  bool GetEMFContentBits(PBYTE aBytes);
+
+ private:
+  WindowsEMF(const WindowsEMF& aEMF) = delete;
+  bool FinishDocument();
+  void ReleaseEMFHandle();
+  void ReleaseAllResource();
+
+  /* Compiled EMF data handle. */
+  HENHMETAFILE mEmf;
+  HDC mDC;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+#endif /* MOZILLA_WIDGET_WINDOWSEMF_H */
diff --git a/widget/windows/WindowsEventLog.h b/widget/windows/WindowsEventLog.h
new file mode 100644
index 0000000000..e98d5077a0
--- /dev/null
+++ b/widget/windows/WindowsEventLog.h
@@ -0,0 +1,99 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_WindowsEventLog_h
+#define mozilla_WindowsEventLog_h
+
+/**
+ * Report messages to the Windows Event Log.
+ */
+
+#include <stdio.h>
+#include <windows.h>
+
+#include "mozilla/Attributes.h"
+#include "mozilla/UniquePtr.h"
+
+/**
+ * This header is intended for self-contained, header-only, utility code for
+ * Win32. It may be used outside of xul.dll, in places such as
+ * default-browser-agent.exe or notificationrouter.dll. If your code creates
+ * dependencies on Mozilla libraries, you should put it elsewhere.
+ */
+
+#define MOZ_WIN_EVENT_LOG_ERROR(source, hr) \
+  mozilla::WriteWindowsEventLogHresult(source, hr, __FUNCTION__, __LINE__)
+#define MOZ_WIN_EVENT_LOG_ERROR_MESSAGE(source, format, ...)              \
+  mozilla::WriteWindowsEventLogErrorMessage(source, format, __FUNCTION__, \
+                                            __LINE__, ##__VA_ARGS__)
+
+namespace mozilla {
+
+static void WriteWindowsEventLogErrorBuffer(const wchar_t* eventSourceName,
+                                            const wchar_t* buffer,
+                                            DWORD eventId) {
+  HANDLE source = RegisterEventSourceW(nullptr, eventSourceName);
+  if (!source) {
+    // Not much we can do about this.
+    return;
+  }
+
+  const wchar_t* stringsArray[] = {buffer};
+  ReportEventW(source, EVENTLOG_ERROR_TYPE, 0, eventId, nullptr, 1, 0,
+               stringsArray, nullptr);
+
+  DeregisterEventSource(source);
+}
+
+inline void WriteWindowsEventLogHresult(const wchar_t* eventSourceName,
+                                        HRESULT hr, const char* sourceFile,
+                                        int sourceLine) {
+  const wchar_t* format = L"0x%X in %S:%d";
+  int bufferSize = _scwprintf(format, hr, sourceFile, sourceLine);
+  ++bufferSize;  // Extra character for terminating null
+  mozilla::UniquePtr<wchar_t[]> errorStr =
+      mozilla::MakeUnique<wchar_t[]>(bufferSize);
+
+  _snwprintf_s(errorStr.get(), bufferSize, _TRUNCATE, format, hr, sourceFile,
+               sourceLine);
+
+  WriteWindowsEventLogErrorBuffer(eventSourceName, errorStr.get(), hr);
+}
+
+MOZ_FORMAT_WPRINTF(1, 4)
+inline void WriteWindowsEventLogErrorMessage(const wchar_t* eventSourceName,
+                                             const wchar_t* messageFormat,
+                                             const char* sourceFile,
+                                             int sourceLine, ...) {
+  // First assemble the passed message
+  va_list ap;
+  va_start(ap, sourceLine);
+  int bufferSize = _vscwprintf(messageFormat, ap);
+  ++bufferSize;  // Extra character for terminating null
+  va_end(ap);
+  mozilla::UniquePtr<wchar_t[]> message =
+      mozilla::MakeUnique<wchar_t[]>(bufferSize);
+
+  va_start(ap, sourceLine);
+  vswprintf(message.get(), bufferSize, messageFormat, ap);
+  va_end(ap);
+
+  // Next, assemble the complete error message to print
+  const wchar_t* errorFormat = L"Error: %s (%S:%d)";
+  bufferSize = _scwprintf(errorFormat, message.get(), sourceFile, sourceLine);
+  ++bufferSize;  // Extra character for terminating null
+  mozilla::UniquePtr<wchar_t[]> errorStr =
+      mozilla::MakeUnique<wchar_t[]>(bufferSize);
+
+  _snwprintf_s(errorStr.get(), bufferSize, _TRUNCATE, errorFormat,
+               message.get(), sourceFile, sourceLine);
+
+  WriteWindowsEventLogErrorBuffer(eventSourceName, errorStr.get(), 0);
+}
+
+}  // namespace mozilla
+
+#endif  // mozilla_WindowsEventLog_h
diff --git a/widget/windows/WindowsSMTCProvider.cpp b/widget/windows/WindowsSMTCProvider.cpp
new file mode 100644
index 0000000000..04d833a8e7
--- /dev/null
+++ b/widget/windows/WindowsSMTCProvider.cpp
@@ -0,0 +1,716 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* mingw currently doesn't support windows.media.h, so we disable
+ * the whole related class until this is fixed.
+ * @TODO: Maybe contact MinGW Team for inclusion?*/
+#ifndef __MINGW32__
+
+#  include "WindowsSMTCProvider.h"
+
+#  include <windows.h>
+#  include <windows.media.h>
+#  include <wrl.h>
+
+#  include "nsMimeTypes.h"
+#  include "mozilla/Assertions.h"
+#  include "mozilla/Logging.h"
+#  include "mozilla/Maybe.h"
+#  include "mozilla/WidgetUtils.h"
+#  include "mozilla/ScopeExit.h"
+#  include "mozilla/dom/MediaControlUtils.h"
+#  include "mozilla/media/MediaUtils.h"
+#  include "nsThreadUtils.h"
+
+#  pragma comment(lib, "runtimeobject.lib")
+
+using namespace ABI::Windows::Foundation;
+using namespace ABI::Windows::Media;
+using namespace ABI::Windows::Storage::Streams;
+using namespace Microsoft::WRL;
+using namespace Microsoft::WRL::Wrappers;
+using namespace mozilla;
+
+#  ifndef RuntimeClass_Windows_Media_SystemMediaTransportControls
+#    define RuntimeClass_Windows_Media_SystemMediaTransportControls \
+      L"Windows.Media.SystemMediaTransportControls"
+#  endif
+
+#  ifndef RuntimeClass_Windows_Storage_Streams_RandomAccessStreamReference
+#    define RuntimeClass_Windows_Storage_Streams_RandomAccessStreamReference \
+      L"Windows.Storage.Streams.RandomAccessStreamReference"
+#  endif
+
+#  ifndef ISystemMediaTransportControlsInterop
+EXTERN_C const IID IID_ISystemMediaTransportControlsInterop;
+MIDL_INTERFACE("ddb0472d-c911-4a1f-86d9-dc3d71a95f5a")
+ISystemMediaTransportControlsInterop : public IInspectable {
+ public:
+  virtual HRESULT STDMETHODCALLTYPE GetForWindow(
+      /* [in] */ __RPC__in HWND appWindow,
+      /* [in] */ __RPC__in REFIID riid,
+      /* [iid_is][retval][out] */
+      __RPC__deref_out_opt void** mediaTransportControl) = 0;
+};
+#  endif /* __ISystemMediaTransportControlsInterop_INTERFACE_DEFINED__ */
+
+extern mozilla::LazyLogModule gMediaControlLog;
+
+#  undef LOG
+#  define LOG(msg, ...)                        \
+    MOZ_LOG(gMediaControlLog, LogLevel::Debug, \
+            ("WindowSMTCProvider=%p, " msg, this, ##__VA_ARGS__))
+
+static inline Maybe<mozilla::dom::MediaControlKey> TranslateKeycode(
+    SystemMediaTransportControlsButton keycode) {
+  switch (keycode) {
+    case SystemMediaTransportControlsButton_Play:
+      return Some(mozilla::dom::MediaControlKey::Play);
+    case SystemMediaTransportControlsButton_Pause:
+      return Some(mozilla::dom::MediaControlKey::Pause);
+    case SystemMediaTransportControlsButton_Next:
+      return Some(mozilla::dom::MediaControlKey::Nexttrack);
+    case SystemMediaTransportControlsButton_Previous:
+      return Some(mozilla::dom::MediaControlKey::Previoustrack);
+    case SystemMediaTransportControlsButton_Stop:
+      return Some(mozilla::dom::MediaControlKey::Stop);
+    case SystemMediaTransportControlsButton_FastForward:
+      return Some(mozilla::dom::MediaControlKey::Seekforward);
+    case SystemMediaTransportControlsButton_Rewind:
+      return Some(mozilla::dom::MediaControlKey::Seekbackward);
+    default:
+      return Nothing();  // Not supported Button
+  }
+}
+
+static IAsyncInfo* GetIAsyncInfo(IAsyncOperation<unsigned int>* aAsyncOp) {
+  MOZ_ASSERT(aAsyncOp);
+  IAsyncInfo* asyncInfo;
+  HRESULT hr = aAsyncOp->QueryInterface(IID_IAsyncInfo,
+                                        reinterpret_cast<void**>(&asyncInfo));
+  // The assertion always works since IAsyncOperation implements IAsyncInfo
+  MOZ_ASSERT(SUCCEEDED(hr));
+  Unused << hr;
+  MOZ_ASSERT(asyncInfo);
+  return asyncInfo;
+}
+
+WindowsSMTCProvider::WindowsSMTCProvider() {
+  LOG("Creating an empty and invisible window");
+
+  // In order to create a SMTC-Provider, we need a hWnd, which shall be created
+  // dynamically from an invisible window. This leads to the following
+  // boilerplate code.
+  WNDCLASS wnd{};
+  wnd.lpszClassName = L"Firefox-MediaKeys";
+  wnd.hInstance = nullptr;
+  wnd.lpfnWndProc = DefWindowProc;
+  GetLastError();  // Clear the error
+  RegisterClass(&wnd);
+  MOZ_ASSERT(!GetLastError());
+
+  mWindow = CreateWindowExW(0, L"Firefox-MediaKeys", L"Firefox Media Keys", 0,
+                            CW_USEDEFAULT, CW_USEDEFAULT, 0, 0, nullptr,
+                            nullptr, nullptr, nullptr);
+  MOZ_ASSERT(mWindow);
+  MOZ_ASSERT(!GetLastError());
+}
+
+WindowsSMTCProvider::~WindowsSMTCProvider() {
+  // Dispose the window
+  MOZ_ASSERT(mWindow);
+  if (!DestroyWindow(mWindow)) {
+    LOG("Failed to destroy the hidden window. Error Code: %lu", GetLastError());
+  }
+  if (!UnregisterClass(L"Firefox-MediaKeys", nullptr)) {
+    // Note that this is logged when the class wasn't even registered.
+    LOG("Failed to unregister the class. Error Code: %lu", GetLastError());
+  }
+}
+
+bool WindowsSMTCProvider::IsOpened() const { return mInitialized; }
+
+bool WindowsSMTCProvider::Open() {
+  LOG("Opening Source");
+  MOZ_ASSERT(!mInitialized);
+
+  if (!InitDisplayAndControls()) {
+    LOG("Failed to initialize the SMTC and its display");
+    return false;
+  }
+
+  if (!UpdateButtons()) {
+    LOG("Failed to initialize the buttons");
+    return false;
+  }
+
+  if (!RegisterEvents()) {
+    LOG("Failed to register SMTC key-event listener");
+    return false;
+  }
+
+  if (!EnableControl(true)) {
+    LOG("Failed to enable SMTC control");
+    return false;
+  }
+
+  mInitialized = true;
+  SetPlaybackState(mozilla::dom::MediaSessionPlaybackState::None);
+  return mInitialized;
+}
+
+void WindowsSMTCProvider::Close() {
+  MediaControlKeySource::Close();
+  // Prevent calling Set methods when init failed
+  if (mInitialized) {
+    SetPlaybackState(mozilla::dom::MediaSessionPlaybackState::None);
+    UnregisterEvents();
+    ClearMetadata();
+    // We have observed an Windows issue, if we modify `mControls` , (such as
+    // setting metadata, disable buttons) before disabling control, and those
+    // operations are not done sequentially within a same main thread task,
+    // then it would cause a problem where the SMTC wasn't clean up completely
+    // and show the executable name.
+    EnableControl(false);
+    mInitialized = false;
+  }
+}
+
+void WindowsSMTCProvider::SetPlaybackState(
+    mozilla::dom::MediaSessionPlaybackState aState) {
+  MOZ_ASSERT(mInitialized);
+  MediaControlKeySource::SetPlaybackState(aState);
+
+  HRESULT hr;
+
+  // Note: we can't return the status of put_PlaybackStatus, but we can at least
+  // assert it.
+  switch (aState) {
+    case mozilla::dom::MediaSessionPlaybackState::Paused:
+      hr = mControls->put_PlaybackStatus(
+          ABI::Windows::Media::MediaPlaybackStatus_Paused);
+      break;
+    case mozilla::dom::MediaSessionPlaybackState::Playing:
+      hr = mControls->put_PlaybackStatus(
+          ABI::Windows::Media::MediaPlaybackStatus_Playing);
+      break;
+    case mozilla::dom::MediaSessionPlaybackState::None:
+      hr = mControls->put_PlaybackStatus(
+          ABI::Windows::Media::MediaPlaybackStatus_Stopped);
+      break;
+      // MediaPlaybackStatus still supports Closed and Changing, which we don't
+      // use (yet)
+    default:
+      MOZ_ASSERT_UNREACHABLE(
+          "Enum Inconsitency between PlaybackState and WindowsSMTCProvider");
+      break;
+  }
+
+  MOZ_ASSERT(SUCCEEDED(hr));
+  Unused << hr;
+}
+
+void WindowsSMTCProvider::SetMediaMetadata(
+    const mozilla::dom::MediaMetadataBase& aMetadata) {
+  MOZ_ASSERT(mInitialized);
+  SetMusicMetadata(aMetadata.mArtist, aMetadata.mTitle);
+  LoadThumbnail(aMetadata.mArtwork);
+}
+
+void WindowsSMTCProvider::ClearMetadata() {
+  MOZ_ASSERT(mDisplay);
+  if (FAILED(mDisplay->ClearAll())) {
+    LOG("Failed to clear SMTC display");
+  }
+  mImageFetchRequest.DisconnectIfExists();
+  CancelPendingStoreAsyncOperation();
+  mThumbnailUrl.Truncate();
+  mProcessingUrl.Truncate();
+  mNextImageIndex = 0;
+  mSupportedKeys = 0;
+}
+
+void WindowsSMTCProvider::SetSupportedMediaKeys(
+    const MediaKeysArray& aSupportedKeys) {
+  MOZ_ASSERT(mInitialized);
+
+  uint32_t supportedKeys = 0;
+  for (const mozilla::dom::MediaControlKey& key : aSupportedKeys) {
+    supportedKeys |= GetMediaKeyMask(key);
+  }
+
+  if (supportedKeys == mSupportedKeys) {
+    LOG("Supported keys stay the same");
+    return;
+  }
+
+  LOG("Update supported keys");
+  mSupportedKeys = supportedKeys;
+  UpdateButtons();
+}
+
+void WindowsSMTCProvider::UnregisterEvents() {
+  if (mControls && mButtonPressedToken.value != 0) {
+    mControls->remove_ButtonPressed(mButtonPressedToken);
+  }
+}
+
+bool WindowsSMTCProvider::RegisterEvents() {
+  MOZ_ASSERT(mControls);
+  auto self = RefPtr<WindowsSMTCProvider>(this);
+  auto callbackbtnPressed = Callback<
+      ITypedEventHandler<SystemMediaTransportControls*,
+                         SystemMediaTransportControlsButtonPressedEventArgs*>>(
+      [this, self](ISystemMediaTransportControls*,
+                   ISystemMediaTransportControlsButtonPressedEventArgs* pArgs)
+          -> HRESULT {
+        MOZ_ASSERT(pArgs);
+        SystemMediaTransportControlsButton btn;
+
+        if (FAILED(pArgs->get_Button(&btn))) {
+          LOG("SystemMediaTransportControls: ButtonPressedEvent - Could "
+              "not get Button.");
+          return S_OK;  // Propagating the error probably wouldn't help.
+        }
+
+        Maybe<mozilla::dom::MediaControlKey> keyCode = TranslateKeycode(btn);
+        if (keyCode.isSome() && IsOpened()) {
+          OnButtonPressed(keyCode.value());
+        }
+        return S_OK;
+      });
+
+  if (FAILED(mControls->add_ButtonPressed(callbackbtnPressed.Get(),
+                                          &mButtonPressedToken))) {
+    LOG("SystemMediaTransportControls: Failed at "
+        "registerEvents().add_ButtonPressed()");
+    return false;
+  }
+
+  return true;
+}
+
+void WindowsSMTCProvider::OnButtonPressed(
+    mozilla::dom::MediaControlKey aKey) const {
+  if (!IsKeySupported(aKey)) {
+    LOG("key: %s is not supported", ToMediaControlKeyStr(aKey));
+    return;
+  }
+
+  for (auto& listener : mListeners) {
+    listener->OnActionPerformed(mozilla::dom::MediaControlAction(aKey));
+  }
+}
+
+bool WindowsSMTCProvider::EnableControl(bool aEnabled) const {
+  MOZ_ASSERT(mControls);
+  return SUCCEEDED(mControls->put_IsEnabled(aEnabled));
+}
+
+bool WindowsSMTCProvider::UpdateButtons() const {
+  static const mozilla::dom::MediaControlKey kKeys[] = {
+      mozilla::dom::MediaControlKey::Play, mozilla::dom::MediaControlKey::Pause,
+      mozilla::dom::MediaControlKey::Previoustrack,
+      mozilla::dom::MediaControlKey::Nexttrack,
+      mozilla::dom::MediaControlKey::Stop};
+
+  bool success = true;
+  for (const mozilla::dom::MediaControlKey& key : kKeys) {
+    if (!EnableKey(key, IsKeySupported(key))) {
+      success = false;
+      LOG("Failed to set %s=%s", ToMediaControlKeyStr(key),
+          IsKeySupported(key) ? "true" : "false");
+    }
+  }
+
+  return success;
+}
+
+bool WindowsSMTCProvider::IsKeySupported(
+    mozilla::dom::MediaControlKey aKey) const {
+  return mSupportedKeys & GetMediaKeyMask(aKey);
+}
+
+bool WindowsSMTCProvider::EnableKey(mozilla::dom::MediaControlKey aKey,
+                                    bool aEnable) const {
+  MOZ_ASSERT(mControls);
+  switch (aKey) {
+    case mozilla::dom::MediaControlKey::Play:
+      return SUCCEEDED(mControls->put_IsPlayEnabled(aEnable));
+    case mozilla::dom::MediaControlKey::Pause:
+      return SUCCEEDED(mControls->put_IsPauseEnabled(aEnable));
+    case mozilla::dom::MediaControlKey::Previoustrack:
+      return SUCCEEDED(mControls->put_IsPreviousEnabled(aEnable));
+    case mozilla::dom::MediaControlKey::Nexttrack:
+      return SUCCEEDED(mControls->put_IsNextEnabled(aEnable));
+    case mozilla::dom::MediaControlKey::Stop:
+      return SUCCEEDED(mControls->put_IsStopEnabled(aEnable));
+    default:
+      LOG("No button for %s", ToMediaControlKeyStr(aKey));
+      return false;
+  }
+}
+
+bool WindowsSMTCProvider::InitDisplayAndControls() {
+  // As Open() might be called multiple times, "cache" the results of the COM
+  // API
+  if (mControls && mDisplay) {
+    return true;
+  }
+  ComPtr<ISystemMediaTransportControlsInterop> interop;
+  HRESULT hr = GetActivationFactory(
+      HStringReference(RuntimeClass_Windows_Media_SystemMediaTransportControls)
+          .Get(),
+      interop.GetAddressOf());
+  if (FAILED(hr)) {
+    LOG("SystemMediaTransportControls: Failed at instantiating the "
+        "Interop object");
+    return false;
+  }
+  MOZ_ASSERT(interop);
+
+  if (!mControls && FAILED(interop->GetForWindow(
+                        mWindow, IID_PPV_ARGS(mControls.GetAddressOf())))) {
+    LOG("SystemMediaTransportControls: Failed at GetForWindow()");
+    return false;
+  }
+  MOZ_ASSERT(mControls);
+
+  if (!mDisplay &&
+      FAILED(mControls->get_DisplayUpdater(mDisplay.GetAddressOf()))) {
+    LOG("SystemMediaTransportControls: Failed at get_DisplayUpdater()");
+  }
+
+  MOZ_ASSERT(mDisplay);
+  return true;
+}
+
+bool WindowsSMTCProvider::SetMusicMetadata(const nsString& aArtist,
+                                           const nsString& aTitle) {
+  MOZ_ASSERT(mDisplay);
+  ComPtr<IMusicDisplayProperties> musicProps;
+
+  HRESULT hr = mDisplay->put_Type(MediaPlaybackType::MediaPlaybackType_Music);
+  MOZ_ASSERT(SUCCEEDED(hr));
+  Unused << hr;
+  hr = mDisplay->get_MusicProperties(musicProps.GetAddressOf());
+  if (FAILED(hr)) {
+    LOG("Failed to get music properties");
+    return false;
+  }
+
+  hr = musicProps->put_Artist(HStringReference(aArtist.get()).Get());
+  if (FAILED(hr)) {
+    LOG("Failed to set the music's artist");
+    return false;
+  }
+
+  hr = musicProps->put_Title(HStringReference(aTitle.get()).Get());
+  if (FAILED(hr)) {
+    LOG("Failed to set the music's title");
+    return false;
+  }
+
+  hr = mDisplay->Update();
+  if (FAILED(hr)) {
+    LOG("Failed to refresh the display");
+    return false;
+  }
+
+  return true;
+}
+
+void WindowsSMTCProvider::LoadThumbnail(
+    const nsTArray<mozilla::dom::MediaImage>& aArtwork) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // TODO: Sort the images by the preferred size or format.
+  mArtwork = aArtwork;
+  mNextImageIndex = 0;
+
+  // Abort the loading if
+  // 1) thumbnail is being updated, and one in processing is in the artwork
+  // 2) thumbnail is not being updated, and one in use is in the artwork
+  if (!mProcessingUrl.IsEmpty()) {
+    LOG("Load thumbnail while image: %s is being processed",
+        NS_ConvertUTF16toUTF8(mProcessingUrl).get());
+    if (mozilla::dom::IsImageIn(mArtwork, mProcessingUrl)) {
+      LOG("No need to load thumbnail. The one being processed is in the "
+          "artwork");
+      return;
+    }
+  } else if (!mThumbnailUrl.IsEmpty()) {
+    if (mozilla::dom::IsImageIn(mArtwork, mThumbnailUrl)) {
+      LOG("No need to load thumbnail. The one in use is in the artwork");
+      return;
+    }
+  }
+
+  // If there is a pending image store operation, that image must be different
+  // from the new image will be loaded below, so the pending one should be
+  // cancelled.
+  CancelPendingStoreAsyncOperation();
+  // Remove the current thumbnail on the interface
+  ClearThumbnail();
+  // Then load the new thumbnail asynchronously
+  LoadImageAtIndex(mNextImageIndex++);
+}
+
+void WindowsSMTCProvider::LoadImageAtIndex(const size_t aIndex) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (aIndex >= mArtwork.Length()) {
+    LOG("Stop loading thumbnail. No more available images");
+    mImageFetchRequest.DisconnectIfExists();
+    mProcessingUrl.Truncate();
+    return;
+  }
+
+  const mozilla::dom::MediaImage& image = mArtwork[aIndex];
+
+  // TODO: No need to fetch the default image and do image processing since the
+  // the default image is local file and it's trustworthy. For the default
+  // image, we can use `CreateFromFile` to create the IRandomAccessStream. We
+  // should probably cache it since it could be used very often (Bug 1643102)
+
+  if (!mozilla::dom::IsValidImageUrl(image.mSrc)) {
+    LOG("Skip the image with invalid URL. Try next image");
+    mImageFetchRequest.DisconnectIfExists();
+    LoadImageAtIndex(mNextImageIndex++);
+    return;
+  }
+
+  mImageFetchRequest.DisconnectIfExists();
+  mProcessingUrl = image.mSrc;
+
+  mImageFetcher = mozilla::MakeUnique<mozilla::dom::FetchImageHelper>(image);
+  RefPtr<WindowsSMTCProvider> self = this;
+  mImageFetcher->FetchImage()
+      ->Then(
+          AbstractThread::MainThread(), __func__,
+          [this, self](const nsCOMPtr<imgIContainer>& aImage) {
+            LOG("The image is fetched successfully");
+            mImageFetchRequest.Complete();
+
+            // Although IMAGE_JPEG or IMAGE_BMP are valid types as well, but a
+            // png image with transparent background will be converted into a
+            // jpeg/bmp file with a colored background. IMAGE_PNG format seems
+            // to be the best choice for now.
+            uint32_t size = 0;
+            char* src = nullptr;
+            // Only used to hold the image data
+            nsCOMPtr<nsIInputStream> inputStream;
+            nsresult rv = mozilla::dom::GetEncodedImageBuffer(
+                aImage, nsLiteralCString(IMAGE_PNG),
+                getter_AddRefs(inputStream), &size, &src);
+            if (NS_FAILED(rv) || !inputStream || size == 0 || !src) {
+              LOG("Failed to get the image buffer info. Try next image");
+              LoadImageAtIndex(mNextImageIndex++);
+              return;
+            }
+
+            LoadImage(src, size);
+          },
+          [this, self](bool) {
+            LOG("Failed to fetch image. Try next image");
+            mImageFetchRequest.Complete();
+            LoadImageAtIndex(mNextImageIndex++);
+          })
+      ->Track(mImageFetchRequest);
+}
+
+void WindowsSMTCProvider::LoadImage(const char* aImageData,
+                                    uint32_t aDataSize) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // 1. Use mImageDataWriter to write the binary data of image into mImageStream
+  // 2. Refer the image by mImageStreamReference and then set it to the SMTC
+  // In case of the race condition between they are being destroyed and the
+  // async operation for image loading, mImageDataWriter, mImageStream, and
+  // mImageStreamReference are member variables
+
+  HRESULT hr = ActivateInstance(
+      HStringReference(
+          RuntimeClass_Windows_Storage_Streams_InMemoryRandomAccessStream)
+          .Get(),
+      mImageStream.GetAddressOf());
+  if (FAILED(hr)) {
+    LOG("Failed to make mImageStream refer to an instance of "
+        "InMemoryRandomAccessStream");
+    return;
+  }
+
+  ComPtr<IOutputStream> outputStream;
+  hr = mImageStream.As(&outputStream);
+  if (FAILED(hr)) {
+    LOG("Failed when query IOutputStream interface from mImageStream");
+    return;
+  }
+
+  ComPtr<IDataWriterFactory> dataWriterFactory;
+  hr = GetActivationFactory(
+      HStringReference(RuntimeClass_Windows_Storage_Streams_DataWriter).Get(),
+      dataWriterFactory.GetAddressOf());
+  if (FAILED(hr)) {
+    LOG("Failed to get an activation factory for IDataWriterFactory");
+    return;
+  }
+
+  hr = dataWriterFactory->CreateDataWriter(outputStream.Get(),
+                                           mImageDataWriter.GetAddressOf());
+  if (FAILED(hr)) {
+    LOG("Failed to create mImageDataWriter that writes data to mImageStream");
+    return;
+  }
+
+  hr = mImageDataWriter->WriteBytes(
+      aDataSize, reinterpret_cast<BYTE*>(const_cast<char*>(aImageData)));
+  if (FAILED(hr)) {
+    LOG("Failed to write data to mImageStream");
+    return;
+  }
+
+  hr = mImageDataWriter->StoreAsync(&mStoreAsyncOperation);
+  if (FAILED(hr)) {
+    LOG("Failed to create a DataWriterStoreOperation for mStoreAsyncOperation");
+    return;
+  }
+
+  // Upon the image is stored in mImageStream, set the image to the SMTC
+  // interface
+  auto onStoreCompleted = Callback<
+      IAsyncOperationCompletedHandler<unsigned int>>(
+      [this, self = RefPtr<WindowsSMTCProvider>(this),
+       aImageUrl = nsString(mProcessingUrl)](
+          IAsyncOperation<unsigned int>* aAsyncOp, AsyncStatus aStatus) {
+        MOZ_ASSERT(NS_IsMainThread());
+
+        if (aStatus != AsyncStatus::Completed) {
+          LOG("Asynchronous operation is not completed");
+          return E_ABORT;
+        }
+
+        HRESULT hr = S_OK;
+        IAsyncInfo* asyncInfo = GetIAsyncInfo(aAsyncOp);
+        asyncInfo->get_ErrorCode(&hr);
+        if (FAILED(hr)) {
+          LOG("Failed to get termination status of the asynchronous operation");
+          return hr;
+        }
+
+        if (!UpdateThumbnail(aImageUrl)) {
+          LOG("Failed to update thumbnail");
+        }
+
+        // If an error occurs above:
+        // - If aImageUrl is not mProcessingUrl. It's fine.
+        // - If aImageUrl is mProcessingUrl, then mProcessingUrl won't be reset.
+        //   Therefore the thumbnail will remain empty until a new image whose
+        //   url is different from mProcessingUrl is loaded.
+
+        return S_OK;
+      });
+
+  hr = mStoreAsyncOperation->put_Completed(onStoreCompleted.Get());
+  if (FAILED(hr)) {
+    LOG("Failed to set callback on completeing the asynchronous operation");
+  }
+}
+
+bool WindowsSMTCProvider::SetThumbnail(const nsAString& aUrl) {
+  MOZ_ASSERT(mDisplay);
+  MOZ_ASSERT(mImageStream);
+  MOZ_ASSERT(!aUrl.IsEmpty());
+
+  ComPtr<IRandomAccessStreamReferenceStatics> streamRefFactory;
+
+  HRESULT hr = GetActivationFactory(
+      HStringReference(
+          RuntimeClass_Windows_Storage_Streams_RandomAccessStreamReference)
+          .Get(),
+      streamRefFactory.GetAddressOf());
+  auto cleanup =
+      MakeScopeExit([this, self = RefPtr<WindowsSMTCProvider>(this)] {
+        LOG("Clean mThumbnailUrl");
+        mThumbnailUrl.Truncate();
+      });
+
+  if (FAILED(hr)) {
+    LOG("Failed to get an activation factory for "
+        "IRandomAccessStreamReferenceStatics type");
+    return false;
+  }
+
+  hr = streamRefFactory->CreateFromStream(mImageStream.Get(),
+                                          mImageStreamReference.GetAddressOf());
+  if (FAILED(hr)) {
+    LOG("Failed to create mImageStreamReference from mImageStream");
+    return false;
+  }
+
+  hr = mDisplay->put_Thumbnail(mImageStreamReference.Get());
+  if (FAILED(hr)) {
+    LOG("Failed to update thumbnail");
+    return false;
+  }
+
+  hr = mDisplay->Update();
+  if (FAILED(hr)) {
+    LOG("Failed to refresh display");
+    return false;
+  }
+
+  // No need to clean mThumbnailUrl since thumbnail is set successfully
+  cleanup.release();
+  mThumbnailUrl = aUrl;
+
+  return true;
+}
+
+void WindowsSMTCProvider::ClearThumbnail() {
+  MOZ_ASSERT(mDisplay);
+  HRESULT hr = mDisplay->put_Thumbnail(nullptr);
+  MOZ_ASSERT(SUCCEEDED(hr));
+  hr = mDisplay->Update();
+  MOZ_ASSERT(SUCCEEDED(hr));
+  Unused << hr;
+  mThumbnailUrl.Truncate();
+}
+
+bool WindowsSMTCProvider::UpdateThumbnail(const nsAString& aUrl) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (!IsOpened()) {
+    LOG("Abort the thumbnail update: SMTC is closed");
+    return false;
+  }
+
+  if (aUrl != mProcessingUrl) {
+    LOG("Abort the thumbnail update: The image from %s is out of date",
+        NS_ConvertUTF16toUTF8(aUrl).get());
+    return false;
+  }
+
+  mProcessingUrl.Truncate();
+
+  if (!SetThumbnail(aUrl)) {
+    LOG("Failed to update thumbnail");
+    return false;
+  }
+
+  MOZ_ASSERT(mThumbnailUrl == aUrl);
+  LOG("The thumbnail is updated to the image from: %s",
+      NS_ConvertUTF16toUTF8(mThumbnailUrl).get());
+  return true;
+}
+
+void WindowsSMTCProvider::CancelPendingStoreAsyncOperation() const {
+  if (mStoreAsyncOperation) {
+    IAsyncInfo* asyncInfo = GetIAsyncInfo(mStoreAsyncOperation.Get());
+    asyncInfo->Cancel();
+  }
+}
+
+#endif  // __MINGW32__
diff --git a/widget/windows/WindowsSMTCProvider.h b/widget/windows/WindowsSMTCProvider.h
new file mode 100644
index 0000000000..3926618d1f
--- /dev/null
+++ b/widget/windows/WindowsSMTCProvider.h
@@ -0,0 +1,128 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_WINDOWS_WINDOWSSTMCPROVIDER_H_
+#define WIDGET_WINDOWS_WINDOWSSTMCPROVIDER_H_
+
+#ifndef __MINGW32__
+
+#  include <functional>
+#  include <Windows.Media.h>
+#  include <wrl.h>
+
+#  include "mozilla/dom/FetchImageHelper.h"
+#  include "mozilla/dom/MediaController.h"
+#  include "mozilla/dom/MediaControlKeySource.h"
+#  include "mozilla/UniquePtr.h"
+
+using ISMTC = ABI::Windows::Media::ISystemMediaTransportControls;
+using SMTCProperty = ABI::Windows::Media::SystemMediaTransportControlsProperty;
+using ISMTCDisplayUpdater =
+    ABI::Windows::Media::ISystemMediaTransportControlsDisplayUpdater;
+
+using ABI::Windows::Foundation::IAsyncOperation;
+using ABI::Windows::Storage::Streams::IDataWriter;
+using ABI::Windows::Storage::Streams::IRandomAccessStream;
+using ABI::Windows::Storage::Streams::IRandomAccessStreamReference;
+using Microsoft::WRL::ComPtr;
+
+class WindowsSMTCProvider final : public mozilla::dom::MediaControlKeySource {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WindowsSMTCProvider, override)
+
+ public:
+  WindowsSMTCProvider();
+
+  bool IsOpened() const override;
+  bool Open() override;
+  void Close() override;
+
+  void SetPlaybackState(
+      mozilla::dom::MediaSessionPlaybackState aState) override;
+
+  void SetMediaMetadata(
+      const mozilla::dom::MediaMetadataBase& aMetadata) override;
+
+  void SetSupportedMediaKeys(const MediaKeysArray& aSupportedKeys) override;
+
+ private:
+  ~WindowsSMTCProvider();
+  void UnregisterEvents();
+  bool RegisterEvents();
+
+  void OnButtonPressed(mozilla::dom::MediaControlKey aKey) const;
+  // Enable the SMTC interface
+  bool EnableControl(bool aEnabled) const;
+  // Sets the play, pause, next, previous buttons on the SMTC interface by
+  // mSupportedKeys
+  bool UpdateButtons() const;
+  bool IsKeySupported(mozilla::dom::MediaControlKey aKey) const;
+  bool EnableKey(mozilla::dom::MediaControlKey aKey, bool aEnable) const;
+
+  bool InitDisplayAndControls();
+
+  // Sets the Metadata for the currently playing media and sets the playback
+  // type to "MUSIC"
+  bool SetMusicMetadata(const nsString& aArtist, const nsString& aTitle);
+
+  // Sets one of the artwork to the SMTC interface asynchronously
+  void LoadThumbnail(const nsTArray<mozilla::dom::MediaImage>& aArtwork);
+  // Stores the image at index aIndex of the mArtwork to the Thumbnail
+  // asynchronously
+  void LoadImageAtIndex(const size_t aIndex);
+  // Stores the raw binary data of an image to mImageStream and set it to the
+  // Thumbnail asynchronously
+  void LoadImage(const char* aImageData, uint32_t aDataSize);
+  // Sets the Thumbnail to the image stored in mImageStream
+  bool SetThumbnail(const nsAString& aUrl);
+  void ClearThumbnail();
+
+  bool UpdateThumbnail(const nsAString& aUrl);
+  void CancelPendingStoreAsyncOperation() const;
+
+  void ClearMetadata();
+
+  bool mInitialized = false;
+
+  // A bit table indicating what keys are enabled
+  uint32_t mSupportedKeys = 0;
+
+  ComPtr<ISMTC> mControls;
+  ComPtr<ISMTCDisplayUpdater> mDisplay;
+
+  // Use mImageDataWriter to write the binary data of image into mImageStream
+  // and refer the image by mImageStreamReference and then set it to the SMTC
+  // interface
+  ComPtr<IDataWriter> mImageDataWriter;
+  ComPtr<IRandomAccessStream> mImageStream;
+  ComPtr<IRandomAccessStreamReference> mImageStreamReference;
+  ComPtr<IAsyncOperation<unsigned int>> mStoreAsyncOperation;
+
+  // mThumbnailUrl is the url of the current Thumbnail
+  // mProcessingUrl is the url that is being processed. The process starts from
+  // fetching an image from the url and then storing the fetched image to the
+  // mImageStream. If mProcessingUrl is not empty, it means there is an image is
+  // in processing
+  // mThumbnailUrl and mProcessingUrl won't be set at the same time and they can
+  // only be touched on main thread
+  nsString mThumbnailUrl;
+  nsString mProcessingUrl;
+
+  // mArtwork can only be used in main thread in case of data racing
+  CopyableTArray<mozilla::dom::MediaImage> mArtwork;
+  size_t mNextImageIndex;
+
+  mozilla::UniquePtr<mozilla::dom::FetchImageHelper> mImageFetcher;
+  mozilla::MozPromiseRequestHolder<mozilla::dom::ImagePromise>
+      mImageFetchRequest;
+
+  HWND mWindow;  // handle to the invisible window
+
+  // EventRegistrationTokens are used to have a handle on a callback (to remove
+  // it again)
+  EventRegistrationToken mButtonPressedToken;
+};
+
+#endif  // __MINGW32__
+#endif  // WIDGET_WINDOWS_WINDOWSSTMCPROVIDER_H_
diff --git a/widget/windows/WindowsUIUtils.cpp b/widget/windows/WindowsUIUtils.cpp
new file mode 100644
index 0000000000..3d5cff7e23
--- /dev/null
+++ b/widget/windows/WindowsUIUtils.cpp
@@ -0,0 +1,809 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <windows.h>
+#include <wrl.h>
+
+#include "nsServiceManagerUtils.h"
+
+#include "WindowsUIUtils.h"
+
+#include "nsIObserverService.h"
+#include "nsIAppShellService.h"
+#include "nsAppShellCID.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/ResultVariant.h"
+#include "mozilla/Services.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/WidgetUtils.h"
+#include "mozilla/WindowsVersion.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/media/MediaUtils.h"
+#include "nsString.h"
+#include "nsGlobalWindowOuter.h"
+#include "nsIWidget.h"
+#include "nsIWindowMediator.h"
+#include "nsPIDOMWindow.h"
+#include "nsWindowGfx.h"
+#include "Units.h"
+
+/* mingw currently doesn't support windows.ui.viewmanagement.h, so we disable it
+ * until it's fixed. */
+
+// See
+// https://github.com/tpn/winsdk-10/blob/master/Include/10.0.14393.0/winrt/windows.ui.viewmanagement.h
+// for the source of some of these definitions for older SDKs.
+#ifndef __MINGW32__
+
+#  include <inspectable.h>
+#  include <roapi.h>
+#  include <windows.ui.viewmanagement.h>
+
+#  pragma comment(lib, "runtimeobject.lib")
+
+using namespace ABI::Windows::UI;
+using namespace ABI::Windows::UI::ViewManagement;
+using namespace Microsoft::WRL;
+using namespace Microsoft::WRL::Wrappers;
+using namespace ABI::Windows::Foundation;
+using namespace ABI::Windows::ApplicationModel::DataTransfer;
+
+#  ifndef RuntimeClass_Windows_UI_ViewManagement_UIViewSettings
+#    define RuntimeClass_Windows_UI_ViewManagement_UIViewSettings \
+      L"Windows.UI.ViewManagement.UIViewSettings"
+#  endif
+
+#  ifndef IUIViewSettingsInterop
+
+using IUIViewSettingsInterop = interface IUIViewSettingsInterop;
+
+MIDL_INTERFACE("3694dbf9-8f68-44be-8ff5-195c98ede8a6")
+IUIViewSettingsInterop : public IInspectable {
+ public:
+  virtual HRESULT STDMETHODCALLTYPE GetForWindow(HWND hwnd, REFIID riid,
+                                                 void** ppv) = 0;
+};
+#  endif
+
+#  ifndef __IDataTransferManagerInterop_INTERFACE_DEFINED__
+#    define __IDataTransferManagerInterop_INTERFACE_DEFINED__
+
+using IDataTransferManagerInterop = interface IDataTransferManagerInterop;
+
+MIDL_INTERFACE("3A3DCD6C-3EAB-43DC-BCDE-45671CE800C8")
+IDataTransferManagerInterop : public IUnknown {
+ public:
+  virtual HRESULT STDMETHODCALLTYPE GetForWindow(
+      HWND appWindow, REFIID riid, void** dataTransferManager) = 0;
+  virtual HRESULT STDMETHODCALLTYPE ShowShareUIForWindow(HWND appWindow) = 0;
+};
+
+#  endif
+
+#  if !defined( \
+      ____x_ABI_CWindows_CApplicationModel_CDataTransfer_CIDataPackage4_INTERFACE_DEFINED__)
+#    define ____x_ABI_CWindows_CApplicationModel_CDataTransfer_CIDataPackage4_INTERFACE_DEFINED__
+
+MIDL_INTERFACE("13a24ec8-9382-536f-852a-3045e1b29a3b")
+IDataPackage4 : public IInspectable {
+ public:
+  virtual HRESULT STDMETHODCALLTYPE add_ShareCanceled(
+      __FITypedEventHandler_2_Windows__CApplicationModel__CDataTransfer__CDataPackage_IInspectable *
+          handler,
+      EventRegistrationToken * token) = 0;
+  virtual HRESULT STDMETHODCALLTYPE remove_ShareCanceled(
+      EventRegistrationToken token) = 0;
+};
+
+#  endif
+
+#  ifndef RuntimeClass_Windows_UI_ViewManagement_UISettings
+#    define RuntimeClass_Windows_UI_ViewManagement_UISettings \
+      L"Windows.UI.ViewManagement.UISettings"
+#  endif
+#  if WINDOWS_FOUNDATION_UNIVERSALAPICONTRACT_VERSION < 0x80000
+namespace ABI {
+namespace Windows {
+namespace UI {
+namespace ViewManagement {
+
+class UISettings;
+class UISettingsAutoHideScrollBarsChangedEventArgs;
+interface IUISettingsAutoHideScrollBarsChangedEventArgs;
+MIDL_INTERFACE("87afd4b2-9146-5f02-8f6b-06d454174c0f")
+IUISettingsAutoHideScrollBarsChangedEventArgs : public IInspectable{};
+
+}  // namespace ViewManagement
+}  // namespace UI
+}  // namespace Windows
+}  // namespace ABI
+
+namespace ABI {
+namespace Windows {
+namespace Foundation {
+
+template <>
+struct __declspec(uuid("808aef30-2660-51b0-9c11-f75dd42006b4"))
+    ITypedEventHandler<ABI::Windows::UI::ViewManagement::UISettings*,
+                       ABI::Windows::UI::ViewManagement::
+                           UISettingsAutoHideScrollBarsChangedEventArgs*>
+    : ITypedEventHandler_impl<
+          ABI::Windows::Foundation::Internal::AggregateType<
+              ABI::Windows::UI::ViewManagement::UISettings*,
+              ABI::Windows::UI::ViewManagement::IUISettings*>,
+          ABI::Windows::Foundation::Internal::AggregateType<
+              ABI::Windows::UI::ViewManagement::
+                  UISettingsAutoHideScrollBarsChangedEventArgs*,
+              ABI::Windows::UI::ViewManagement::
+                  IUISettingsAutoHideScrollBarsChangedEventArgs*>> {
+  static const wchar_t* z_get_rc_name_impl() {
+    return L"Windows.Foundation.TypedEventHandler`2<Windows.UI.ViewManagement."
+           L"UISettings, "
+           L"Windows.UI.ViewManagement."
+           L"UISettingsAutoHideScrollBarsChangedEventArgs>";
+  }
+};
+// Define a typedef for the parameterized interface specialization's mangled
+// name. This allows code which uses the mangled name for the parameterized
+// interface to access the correct parameterized interface specialization.
+typedef ITypedEventHandler<ABI::Windows::UI::ViewManagement::UISettings*,
+                           ABI::Windows::UI::ViewManagement::
+                               UISettingsAutoHideScrollBarsChangedEventArgs*>
+    __FITypedEventHandler_2_Windows__CUI__CViewManagement__CUISettings_Windows__CUI__CViewManagement__CUISettingsAutoHideScrollBarsChangedEventArgs_t;
+#    define __FITypedEventHandler_2_Windows__CUI__CViewManagement__CUISettings_Windows__CUI__CViewManagement__CUISettingsAutoHideScrollBarsChangedEventArgs \
+      ABI::Windows::Foundation::                                                                                                                            \
+          __FITypedEventHandler_2_Windows__CUI__CViewManagement__CUISettings_Windows__CUI__CViewManagement__CUISettingsAutoHideScrollBarsChangedEventArgs_t
+
+}  // namespace Foundation
+}  // namespace Windows
+}  // namespace ABI
+
+namespace ABI {
+namespace Windows {
+namespace UI {
+namespace ViewManagement {
+class UISettings;
+class UISettingsAutoHideScrollBarsChangedEventArgs;
+interface IUISettings5;
+MIDL_INTERFACE("5349d588-0cb5-5f05-bd34-706b3231f0bd")
+IUISettings5 : public IInspectable {
+ public:
+  virtual HRESULT STDMETHODCALLTYPE get_AutoHideScrollBars(boolean * value) = 0;
+  virtual HRESULT STDMETHODCALLTYPE add_AutoHideScrollBarsChanged(
+      __FITypedEventHandler_2_Windows__CUI__CViewManagement__CUISettings_Windows__CUI__CViewManagement__CUISettingsAutoHideScrollBarsChangedEventArgs *
+          handler,
+      EventRegistrationToken * token) = 0;
+  virtual HRESULT STDMETHODCALLTYPE remove_AutoHideScrollBarsChanged(
+      EventRegistrationToken token) = 0;
+};
+}  // namespace ViewManagement
+}  // namespace UI
+}  // namespace Windows
+}  // namespace ABI
+#  endif
+#endif
+
+using namespace mozilla;
+
+enum class TabletModeState : uint8_t { Unknown, Off, On };
+static TabletModeState sInTabletModeState;
+
+WindowsUIUtils::WindowsUIUtils() = default;
+WindowsUIUtils::~WindowsUIUtils() = default;
+
+NS_IMPL_ISUPPORTS(WindowsUIUtils, nsIWindowsUIUtils)
+
+NS_IMETHODIMP
+WindowsUIUtils::GetSystemSmallIconSize(int32_t* aSize) {
+  NS_ENSURE_ARG(aSize);
+
+  mozilla::LayoutDeviceIntSize size =
+      nsWindowGfx::GetIconMetrics(nsWindowGfx::kSmallIcon);
+  *aSize = std::max(size.width, size.height);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WindowsUIUtils::GetSystemLargeIconSize(int32_t* aSize) {
+  NS_ENSURE_ARG(aSize);
+
+  mozilla::LayoutDeviceIntSize size =
+      nsWindowGfx::GetIconMetrics(nsWindowGfx::kRegularIcon);
+  *aSize = std::max(size.width, size.height);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WindowsUIUtils::SetWindowIcon(mozIDOMWindowProxy* aWindow,
+                              imgIContainer* aSmallIcon,
+                              imgIContainer* aBigIcon) {
+  NS_ENSURE_ARG(aWindow);
+
+  nsCOMPtr<nsIWidget> widget =
+      nsGlobalWindowOuter::Cast(aWindow)->GetMainWidget();
+  nsWindow* window = static_cast<nsWindow*>(widget.get());
+
+  nsresult rv;
+
+  if (aSmallIcon) {
+    HICON hIcon = nullptr;
+    rv = nsWindowGfx::CreateIcon(
+        aSmallIcon, false, mozilla::LayoutDeviceIntPoint(),
+        nsWindowGfx::GetIconMetrics(nsWindowGfx::kSmallIcon), &hIcon);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    window->SetSmallIcon(hIcon);
+  }
+
+  if (aBigIcon) {
+    HICON hIcon = nullptr;
+    rv = nsWindowGfx::CreateIcon(
+        aBigIcon, false, mozilla::LayoutDeviceIntPoint(),
+        nsWindowGfx::GetIconMetrics(nsWindowGfx::kRegularIcon), &hIcon);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    window->SetBigIcon(hIcon);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WindowsUIUtils::SetWindowIconFromExe(mozIDOMWindowProxy* aWindow,
+                                     const nsAString& aExe, uint16_t aIndex) {
+  NS_ENSURE_ARG(aWindow);
+
+  nsCOMPtr<nsIWidget> widget =
+      nsGlobalWindowOuter::Cast(aWindow)->GetMainWidget();
+  nsWindow* window = static_cast<nsWindow*>(widget.get());
+
+  HICON icon = ::LoadIconW(::GetModuleHandleW(PromiseFlatString(aExe).get()),
+                           MAKEINTRESOURCEW(aIndex));
+  window->SetBigIcon(icon);
+  window->SetSmallIcon(icon);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+WindowsUIUtils::SetWindowIconNoData(mozIDOMWindowProxy* aWindow) {
+  NS_ENSURE_ARG(aWindow);
+
+  nsCOMPtr<nsIWidget> widget =
+      nsGlobalWindowOuter::Cast(aWindow)->GetMainWidget();
+  nsWindow* window = static_cast<nsWindow*>(widget.get());
+
+  window->SetSmallIconNoData();
+  window->SetBigIconNoData();
+
+  return NS_OK;
+}
+
+bool WindowsUIUtils::GetInTabletMode() {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+  if (sInTabletModeState == TabletModeState::Unknown) {
+    UpdateInTabletMode();
+  }
+  return sInTabletModeState == TabletModeState::On;
+}
+
+NS_IMETHODIMP
+WindowsUIUtils::GetInTabletMode(bool* aResult) {
+  *aResult = GetInTabletMode();
+  return NS_OK;
+}
+
+static IInspectable* GetUISettings() {
+  MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+#ifndef __MINGW32__
+  // We need to keep this alive for ~ever so that change callbacks work as
+  // expected, sigh.
+  static StaticRefPtr<IInspectable> sUiSettingsAsInspectable;
+
+  if (!sUiSettingsAsInspectable) {
+    ComPtr<IInspectable> uiSettingsAsInspectable;
+    ::RoActivateInstance(
+        HStringReference(RuntimeClass_Windows_UI_ViewManagement_UISettings)
+            .Get(),
+        &uiSettingsAsInspectable);
+    if (NS_WARN_IF(!uiSettingsAsInspectable)) {
+      return nullptr;
+    }
+
+    ComPtr<IUISettings5> uiSettings5;
+    if (SUCCEEDED(uiSettingsAsInspectable.As(&uiSettings5))) {
+      EventRegistrationToken unusedToken;
+      auto callback = Callback<ITypedEventHandler<
+          UISettings*, UISettingsAutoHideScrollBarsChangedEventArgs*>>(
+          [](auto...) {
+            // Scrollbar sizes change layout.
+            LookAndFeel::NotifyChangedAllWindows(
+                widget::ThemeChangeKind::StyleAndLayout);
+            return S_OK;
+          });
+      (void)NS_WARN_IF(FAILED(uiSettings5->add_AutoHideScrollBarsChanged(
+          callback.Get(), &unusedToken)));
+    }
+
+    ComPtr<IUISettings2> uiSettings2;
+    if (SUCCEEDED(uiSettingsAsInspectable.As(&uiSettings2))) {
+      EventRegistrationToken unusedToken;
+      auto callback =
+          Callback<ITypedEventHandler<UISettings*, IInspectable*>>([](auto...) {
+            // Text scale factor changes style and layout.
+            LookAndFeel::NotifyChangedAllWindows(
+                widget::ThemeChangeKind::StyleAndLayout);
+            return S_OK;
+          });
+      (void)NS_WARN_IF(FAILED(uiSettings2->add_TextScaleFactorChanged(
+          callback.Get(), &unusedToken)));
+    }
+
+    ComPtr<IUISettings3> uiSettings3;
+    if (SUCCEEDED(uiSettingsAsInspectable.As(&uiSettings3))) {
+      EventRegistrationToken unusedToken;
+      auto callback =
+          Callback<ITypedEventHandler<UISettings*, IInspectable*>>([](auto...) {
+            // System color changes change style only.
+            LookAndFeel::NotifyChangedAllWindows(
+                widget::ThemeChangeKind::Style);
+            return S_OK;
+          });
+      (void)NS_WARN_IF(FAILED(
+          uiSettings3->add_ColorValuesChanged(callback.Get(), &unusedToken)));
+    }
+
+    ComPtr<IUISettings4> uiSettings4;
+    if (SUCCEEDED(uiSettingsAsInspectable.As(&uiSettings4))) {
+      EventRegistrationToken unusedToken;
+      auto callback =
+          Callback<ITypedEventHandler<UISettings*, IInspectable*>>([](auto...) {
+            // Transparent effects changes change media queries only.
+            LookAndFeel::NotifyChangedAllWindows(
+                widget::ThemeChangeKind::MediaQueriesOnly);
+            return S_OK;
+          });
+      (void)NS_WARN_IF(FAILED(uiSettings4->add_AdvancedEffectsEnabledChanged(
+          callback.Get(), &unusedToken)));
+    }
+
+    sUiSettingsAsInspectable = dont_AddRef(uiSettingsAsInspectable.Detach());
+    ClearOnShutdown(&sUiSettingsAsInspectable);
+  }
+
+  return sUiSettingsAsInspectable.get();
+#else
+  return nullptr;
+#endif
+}
+
+Maybe<nscolor> WindowsUIUtils::GetAccentColor(int aTone) {
+  MOZ_ASSERT(aTone >= -3);
+  MOZ_ASSERT(aTone <= 3);
+#ifndef __MINGW32__
+  ComPtr<IInspectable> settings = GetUISettings();
+  if (NS_WARN_IF(!settings)) {
+    return Nothing();
+  }
+  ComPtr<IUISettings3> uiSettings3;
+  if (NS_WARN_IF(FAILED(settings.As(&uiSettings3)))) {
+    return Nothing();
+  }
+  Color color;
+  auto colorType = UIColorType(int(UIColorType_Accent) + aTone);
+  if (NS_WARN_IF(FAILED(uiSettings3->GetColorValue(colorType, &color)))) {
+    return Nothing();
+  }
+  return Some(NS_RGBA(color.R, color.G, color.B, color.A));
+#else
+  return Nothing();
+#endif
+}
+
+Maybe<nscolor> WindowsUIUtils::GetSystemColor(ColorScheme aScheme,
+                                              int aSysColor) {
+#ifndef __MINGW32__
+  if (!StaticPrefs::widget_windows_uwp_system_colors_enabled()) {
+    return Nothing();
+  }
+
+  // https://docs.microsoft.com/en-us/windows/apps/design/style/color
+  // Is a useful resource to see which values have decent contrast.
+  if (StaticPrefs::widget_windows_uwp_system_colors_highlight_accent()) {
+    if (aSysColor == COLOR_HIGHLIGHT) {
+      int tone = aScheme == ColorScheme::Light ? 0 : -1;
+      if (auto c = GetAccentColor(tone)) {
+        return c;
+      }
+    }
+    if (aSysColor == COLOR_HIGHLIGHTTEXT && GetAccentColor()) {
+      return Some(NS_RGBA(255, 255, 255, 255));
+    }
+  }
+
+  if (aScheme == ColorScheme::Dark) {
+    // There are no explicitly dark colors in UWP, other than the highlight
+    // colors above.
+    return Nothing();
+  }
+
+  auto knownType = [&]() -> Maybe<UIElementType> {
+#  define MAP(_win32, _uwp) \
+    case COLOR_##_win32:    \
+      return Some(UIElementType_##_uwp)
+    switch (aSysColor) {
+      MAP(HIGHLIGHT, Highlight);
+      MAP(HIGHLIGHTTEXT, HighlightText);
+      MAP(ACTIVECAPTION, ActiveCaption);
+      MAP(BTNFACE, ButtonFace);
+      MAP(BTNTEXT, ButtonText);
+      MAP(CAPTIONTEXT, CaptionText);
+      MAP(GRAYTEXT, GrayText);
+      MAP(HOTLIGHT, Hotlight);
+      MAP(INACTIVECAPTION, InactiveCaption);
+      MAP(INACTIVECAPTIONTEXT, InactiveCaptionText);
+      MAP(WINDOW, Window);
+      MAP(WINDOWTEXT, WindowText);
+      default:
+        return Nothing();
+    }
+#  undef MAP
+  }();
+  if (!knownType) {
+    return Nothing();
+  }
+  ComPtr<IInspectable> settings = GetUISettings();
+  if (NS_WARN_IF(!settings)) {
+    return Nothing();
+  }
+  ComPtr<IUISettings> uiSettings;
+  if (NS_WARN_IF(FAILED(settings.As(&uiSettings)))) {
+    return Nothing();
+  }
+  Color color;
+  if (NS_WARN_IF(FAILED(uiSettings->UIElementColor(*knownType, &color)))) {
+    return Nothing();
+  }
+  return Some(NS_RGBA(color.R, color.G, color.B, color.A));
+#else
+  return Nothing();
+#endif
+}
+bool WindowsUIUtils::ComputeOverlayScrollbars() {
+#ifndef __MINGW32__
+  if (!IsWin11OrLater()) {
+    // While in theory Windows 10 supports overlay scrollbar settings, it's off
+    // by default and it's untested whether our Win10 scrollbar drawing code
+    // deals with it properly.
+    return false;
+  }
+  if (!StaticPrefs::widget_windows_overlay_scrollbars_enabled()) {
+    return false;
+  }
+  ComPtr<IInspectable> settings = GetUISettings();
+  if (NS_WARN_IF(!settings)) {
+    return false;
+  }
+  ComPtr<IUISettings5> uiSettings5;
+  if (NS_WARN_IF(FAILED(settings.As(&uiSettings5)))) {
+    return false;
+  }
+  boolean autoHide = false;
+  if (NS_WARN_IF(FAILED(uiSettings5->get_AutoHideScrollBars(&autoHide)))) {
+    return false;
+  }
+  return autoHide;
+#else
+  return false;
+#endif
+}
+
+double WindowsUIUtils::ComputeTextScaleFactor() {
+#ifndef __MINGW32__
+  ComPtr<IInspectable> settings = GetUISettings();
+  if (NS_WARN_IF(!settings)) {
+    return 1.0;
+  }
+  ComPtr<IUISettings2> uiSettings2;
+  if (NS_WARN_IF(FAILED(settings.As(&uiSettings2)))) {
+    return false;
+  }
+  double scaleFactor = 1.0;
+  if (NS_WARN_IF(FAILED(uiSettings2->get_TextScaleFactor(&scaleFactor)))) {
+    return 1.0;
+  }
+  return scaleFactor;
+#else
+  return 1.0;
+#endif
+}
+
+bool WindowsUIUtils::ComputeTransparencyEffects() {
+  constexpr bool kDefault = true;
+#ifndef __MINGW32__
+  ComPtr<IInspectable> settings = GetUISettings();
+  if (NS_WARN_IF(!settings)) {
+    return kDefault;
+  }
+  ComPtr<IUISettings4> uiSettings4;
+  if (NS_WARN_IF(FAILED(settings.As(&uiSettings4)))) {
+    return kDefault;
+  }
+  boolean transparencyEffects = kDefault;
+  if (NS_WARN_IF(FAILED(
+          uiSettings4->get_AdvancedEffectsEnabled(&transparencyEffects)))) {
+    return kDefault;
+  }
+  return transparencyEffects;
+#else
+  return kDefault;
+#endif
+}
+
+void WindowsUIUtils::UpdateInTabletMode() {
+#ifndef __MINGW32__
+  nsresult rv;
+  nsCOMPtr<nsIWindowMediator> winMediator(
+      do_GetService(NS_WINDOWMEDIATOR_CONTRACTID, &rv));
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  nsCOMPtr<nsIWidget> widget;
+  nsCOMPtr<mozIDOMWindowProxy> navWin;
+
+  rv = winMediator->GetMostRecentWindow(u"navigator:browser",
+                                        getter_AddRefs(navWin));
+  if (NS_FAILED(rv) || !navWin) {
+    // Fall back to the hidden window
+    nsCOMPtr<nsIAppShellService> appShell(
+        do_GetService(NS_APPSHELLSERVICE_CONTRACTID));
+
+    rv = appShell->GetHiddenDOMWindow(getter_AddRefs(navWin));
+    if (NS_FAILED(rv) || !navWin) {
+      return;
+    }
+  }
+
+  nsPIDOMWindowOuter* win = nsPIDOMWindowOuter::From(navWin);
+  widget = widget::WidgetUtils::DOMWindowToWidget(win);
+
+  if (!widget) {
+    return;
+  }
+
+  HWND winPtr = (HWND)widget->GetNativeData(NS_NATIVE_WINDOW);
+  ComPtr<IUIViewSettingsInterop> uiViewSettingsInterop;
+
+  HRESULT hr = GetActivationFactory(
+      HStringReference(RuntimeClass_Windows_UI_ViewManagement_UIViewSettings)
+          .Get(),
+      &uiViewSettingsInterop);
+  if (FAILED(hr)) {
+    return;
+  }
+  ComPtr<IUIViewSettings> uiViewSettings;
+  hr = uiViewSettingsInterop->GetForWindow(winPtr,
+                                           IID_PPV_ARGS(&uiViewSettings));
+  if (FAILED(hr)) {
+    return;
+  }
+  UserInteractionMode mode;
+  hr = uiViewSettings->get_UserInteractionMode(&mode);
+  if (FAILED(hr)) {
+    return;
+  }
+
+  TabletModeState oldTabletModeState = sInTabletModeState;
+  sInTabletModeState = mode == UserInteractionMode_Touch ? TabletModeState::On
+                                                         : TabletModeState::Off;
+  if (sInTabletModeState != oldTabletModeState) {
+    nsCOMPtr<nsIObserverService> observerService =
+        mozilla::services::GetObserverService();
+    observerService->NotifyObservers(nullptr, "tablet-mode-change",
+                                     sInTabletModeState == TabletModeState::On
+                                         ? u"tablet-mode"
+                                         : u"normal-mode");
+  }
+#endif
+}
+
+#ifndef __MINGW32__
+struct HStringDeleter {
+  using pointer = HSTRING;
+  void operator()(pointer aString) { WindowsDeleteString(aString); }
+};
+
+using HStringUniquePtr = UniquePtr<HSTRING, HStringDeleter>;
+
+Result<HStringUniquePtr, HRESULT> ConvertToWindowsString(
+    const nsAString& aStr) {
+  HSTRING rawStr;
+  HRESULT hr = WindowsCreateString(PromiseFlatString(aStr).get(), aStr.Length(),
+                                   &rawStr);
+  if (FAILED(hr)) {
+    return Err(hr);
+  }
+  return HStringUniquePtr(rawStr);
+}
+
+static Result<Ok, nsresult> RequestShare(
+    const std::function<HRESULT(IDataRequestedEventArgs* pArgs)>& aCallback) {
+  HWND hwnd = GetForegroundWindow();
+  if (!hwnd) {
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  ComPtr<IDataTransferManagerInterop> dtmInterop;
+  ComPtr<IDataTransferManager> dtm;
+
+  HRESULT hr = RoGetActivationFactory(
+      HStringReference(
+          RuntimeClass_Windows_ApplicationModel_DataTransfer_DataTransferManager)
+          .Get(),
+      IID_PPV_ARGS(&dtmInterop));
+  if (FAILED(hr) ||
+      FAILED(dtmInterop->GetForWindow(hwnd, IID_PPV_ARGS(&dtm)))) {
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  auto callback = Callback<
+      ITypedEventHandler<DataTransferManager*, DataRequestedEventArgs*>>(
+      [aCallback](IDataTransferManager*,
+                  IDataRequestedEventArgs* pArgs) -> HRESULT {
+        return aCallback(pArgs);
+      });
+
+  EventRegistrationToken dataRequestedToken;
+  if (FAILED(dtm->add_DataRequested(callback.Get(), &dataRequestedToken)) ||
+      FAILED(dtmInterop->ShowShareUIForWindow(hwnd))) {
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  return Ok();
+}
+
+static Result<Ok, nsresult> AddShareEventListeners(
+    const RefPtr<mozilla::media::Refcountable<MozPromiseHolder<SharePromise>>>&
+        aPromiseHolder,
+    const ComPtr<IDataPackage>& aDataPackage) {
+  ComPtr<IDataPackage3> spDataPackage3;
+
+  if (FAILED(aDataPackage.As(&spDataPackage3))) {
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  auto completedCallback =
+      Callback<ITypedEventHandler<DataPackage*, ShareCompletedEventArgs*>>(
+          [aPromiseHolder](IDataPackage*,
+                           IShareCompletedEventArgs*) -> HRESULT {
+            aPromiseHolder->Resolve(true, __func__);
+            return S_OK;
+          });
+
+  EventRegistrationToken dataRequestedToken;
+  if (FAILED(spDataPackage3->add_ShareCompleted(completedCallback.Get(),
+                                                &dataRequestedToken))) {
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  ComPtr<IDataPackage4> spDataPackage4;
+  if (SUCCEEDED(aDataPackage.As(&spDataPackage4))) {
+    // Use SharedCanceled API only on supported versions of Windows
+    // So that the older ones can still use ShareUrl()
+
+    auto canceledCallback =
+        Callback<ITypedEventHandler<DataPackage*, IInspectable*>>(
+            [aPromiseHolder](IDataPackage*, IInspectable*) -> HRESULT {
+              aPromiseHolder->Reject(NS_ERROR_FAILURE, __func__);
+              return S_OK;
+            });
+
+    if (FAILED(spDataPackage4->add_ShareCanceled(canceledCallback.Get(),
+                                                 &dataRequestedToken))) {
+      return Err(NS_ERROR_FAILURE);
+    }
+  }
+
+  return Ok();
+}
+#endif
+
+RefPtr<SharePromise> WindowsUIUtils::Share(nsAutoString aTitle,
+                                           nsAutoString aText,
+                                           nsAutoString aUrl) {
+  auto promiseHolder = MakeRefPtr<
+      mozilla::media::Refcountable<MozPromiseHolder<SharePromise>>>();
+  RefPtr<SharePromise> promise = promiseHolder->Ensure(__func__);
+
+#ifndef __MINGW32__
+  auto result = RequestShare([promiseHolder, title = std::move(aTitle),
+                              text = std::move(aText), url = std::move(aUrl)](
+                                 IDataRequestedEventArgs* pArgs) {
+    ComPtr<IDataRequest> spDataRequest;
+    ComPtr<IDataPackage> spDataPackage;
+    ComPtr<IDataPackage2> spDataPackage2;
+    ComPtr<IDataPackagePropertySet> spDataPackageProperties;
+
+    if (FAILED(pArgs->get_Request(&spDataRequest)) ||
+        FAILED(spDataRequest->get_Data(&spDataPackage)) ||
+        FAILED(spDataPackage.As(&spDataPackage2)) ||
+        FAILED(spDataPackage->get_Properties(&spDataPackageProperties))) {
+      promiseHolder->Reject(NS_ERROR_FAILURE, __func__);
+      return E_FAIL;
+    }
+
+    /*
+     * Windows always requires a title, and an empty string does not work.
+     * Thus we trick the API by passing a whitespace when we have no title.
+     * https://docs.microsoft.com/en-us/windows/uwp/app-to-app/share-data
+     */
+    auto wTitle = ConvertToWindowsString((title.IsVoid() || title.Length() == 0)
+                                             ? nsAutoString(u" "_ns)
+                                             : title);
+    if (wTitle.isErr() ||
+        FAILED(spDataPackageProperties->put_Title(wTitle.unwrap().get()))) {
+      promiseHolder->Reject(NS_ERROR_FAILURE, __func__);
+      return E_FAIL;
+    }
+
+    // Assign even if empty, as Windows requires some data to share
+    auto wText = ConvertToWindowsString(text);
+    if (wText.isErr() || FAILED(spDataPackage->SetText(wText.unwrap().get()))) {
+      promiseHolder->Reject(NS_ERROR_FAILURE, __func__);
+      return E_FAIL;
+    }
+
+    if (!url.IsVoid()) {
+      auto wUrl = ConvertToWindowsString(url);
+      if (wUrl.isErr()) {
+        promiseHolder->Reject(NS_ERROR_FAILURE, __func__);
+        return wUrl.unwrapErr();
+      }
+
+      ComPtr<IUriRuntimeClassFactory> uriFactory;
+      ComPtr<IUriRuntimeClass> uri;
+
+      auto hr = GetActivationFactory(
+          HStringReference(RuntimeClass_Windows_Foundation_Uri).Get(),
+          &uriFactory);
+
+      if (FAILED(hr) ||
+          FAILED(uriFactory->CreateUri(wUrl.unwrap().get(), &uri)) ||
+          FAILED(spDataPackage2->SetWebLink(uri.Get()))) {
+        promiseHolder->Reject(NS_ERROR_FAILURE, __func__);
+        return E_FAIL;
+      }
+    }
+
+    if (!StaticPrefs::widget_windows_share_wait_action_enabled()) {
+      promiseHolder->Resolve(true, __func__);
+    } else if (AddShareEventListeners(promiseHolder, spDataPackage).isErr()) {
+      promiseHolder->Reject(NS_ERROR_FAILURE, __func__);
+      return E_FAIL;
+    }
+
+    return S_OK;
+  });
+  if (result.isErr()) {
+    promiseHolder->Reject(result.unwrapErr(), __func__);
+  }
+#else
+  promiseHolder->Reject(NS_ERROR_FAILURE, __func__);
+#endif
+
+  return promise;
+}
+
+NS_IMETHODIMP
+WindowsUIUtils::ShareUrl(const nsAString& aUrlToShare,
+                         const nsAString& aShareTitle) {
+  nsAutoString text;
+  text.SetIsVoid(true);
+  WindowsUIUtils::Share(nsAutoString(aShareTitle), text,
+                        nsAutoString(aUrlToShare));
+  return NS_OK;
+}
diff --git a/widget/windows/WindowsUIUtils.h b/widget/windows/WindowsUIUtils.h
new file mode 100644
index 0000000000..a55f92c8da
--- /dev/null
+++ b/widget/windows/WindowsUIUtils.h
@@ -0,0 +1,50 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_widget_WindowsUIUtils_h__
+#define mozilla_widget_WindowsUIUtils_h__
+
+#include "nsIWindowsUIUtils.h"
+#include "nsString.h"
+#include "nsColor.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/MozPromise.h"
+
+using SharePromise =
+    mozilla::MozPromise<bool, nsresult, /* IsExclusive */ true>;
+
+namespace mozilla {
+enum class ColorScheme : uint8_t;
+}
+
+class WindowsUIUtils final : public nsIWindowsUIUtils {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIWINDOWSUIUTILS
+
+  WindowsUIUtils();
+
+  static RefPtr<SharePromise> Share(nsAutoString aTitle, nsAutoString aText,
+                                    nsAutoString aUrl);
+
+  static void UpdateInTabletMode();
+  static bool GetInTabletMode();
+
+  // Gets the system accent color, or one of the darker / lighter variants
+  // (darker = -1/2/3, lighter=+1/2/3, values outside of that range are
+  // disallowed).
+  static mozilla::Maybe<nscolor> GetAccentColor(int aTone = 0);
+  static mozilla::Maybe<nscolor> GetSystemColor(mozilla::ColorScheme, int);
+
+  // Use LookAndFeel for a cached getter.
+  static bool ComputeOverlayScrollbars();
+  static double ComputeTextScaleFactor();
+  static bool ComputeTransparencyEffects();
+
+ protected:
+  ~WindowsUIUtils();
+};
+
+#endif  // mozilla_widget_WindowsUIUtils_h__
diff --git a/widget/windows/components.conf b/widget/windows/components.conf
new file mode 100644
index 0000000000..e5089ed9e1
--- /dev/null
+++ b/widget/windows/components.conf
@@ -0,0 +1,220 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Headers = [
+    '/widget/windows/nsWidgetFactory.h',
+]
+
+InitFunc = 'nsWidgetWindowsModuleCtor'
+UnloadFunc = 'nsWidgetWindowsModuleDtor'
+
+Classes = [
+    {
+        'cid': '{4c9dee4a-b083-4261-8bbe-c6883d2a6bc9}',
+        'contract_ids': ['@mozilla.org/gfx/parent/screenmanager;1'],
+        'singleton': True,
+        'type': 'mozilla::widget::ScreenManager',
+        'constructor': 'mozilla::widget::ScreenManager::GetAddRefedSingleton',
+        'headers': ['/widget/ScreenManager.h'],
+        'processes': ProcessSelector.ALLOW_IN_GPU_AND_MAIN_PROCESS,
+    },
+    {
+        'cid': '{2d96b3df-c051-11d1-a827-0040959a28c9}',
+        'contract_ids': ['@mozilla.org/widget/appshell/win;1'],
+        'headers': ['/widget/windows/nsWidgetFactory.h'],
+        'legacy_constructor': 'nsAppShellConstructor',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_VR_SOCKET_UTILITY_AND_GMPLUGIN_PROCESS,
+    },
+    {
+        'cid': '{6987230e-0098-4e78-bc5f-1493ee7519fa}',
+        'contract_ids': ['@mozilla.org/widget/useridleservice;1'],
+        'singleton': True,
+        'type': 'nsUserIdleServiceWin',
+        'constructor': 'nsUserIdleServiceWin::GetInstance',
+        'headers': ['/widget/windows/nsUserIdleServiceWin.h', 'nsUserIdleService.h'],
+    },
+    {
+        'cid': '{b148eed2-236d-11d3-b35c-00a0cc3c1cde}',
+        'contract_ids': ['@mozilla.org/sound;1'],
+        'singleton': True,
+        'type': 'nsISound',
+        'constructor': 'nsSound::GetInstance',
+        'headers': ['/widget/windows/nsSound.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{77221d5a-1dd2-11b2-8c69-c710f15d2ed5}',
+        'contract_ids': ['@mozilla.org/widget/clipboardhelper;1'],
+        'type': 'nsClipboardHelper',
+        'headers': ['/widget/nsClipboardHelper.h'],
+    },
+    {
+        'cid': '{b8e5bc54-a22f-4eb2-b061-24cb6d19c15f}',
+        'contract_ids': ['@mozilla.org/windows-taskbar;1'],
+        'type': 'mozilla::widget::WinTaskbar',
+        'headers': ['/widget/windows/WinTaskbar.h'],
+    },
+    {
+        'cid': '{73a5946f-608d-454f-9d33-0b8f8c7294b6}',
+        'contract_ids': ['@mozilla.org/windows-legacyjumplistbuilder;1'],
+        'type': 'mozilla::widget::LegacyJumpListBuilder',
+        'headers': ['/widget/windows/LegacyJumpListBuilder.h'],
+    },
+    {
+        'cid': '{2b9a1f2c-27ce-45b6-8d4e-755d0e34f8db}',
+        'contract_ids': ['@mozilla.org/windows-legacyjumplistitem;1'],
+        'type': 'mozilla::widget::LegacyJumpListItem',
+        'headers': ['/widget/windows/LegacyJumpListItem.h'],
+    },
+    {
+        'cid': '{21f1f13b-f75a-42ad-867a-d91ad694447e}',
+        'contract_ids': ['@mozilla.org/windows-legacyjumplistseparator;1'],
+        'type': 'mozilla::widget::LegacyJumpListSeparator',
+        'headers': ['/widget/windows/LegacyJumpListItem.h'],
+    },
+    {
+        'cid': '{f72c5dc4-5a12-47be-be28-ab105f33b08f}',
+        'contract_ids': ['@mozilla.org/windows-legacyjumplistlink;1'],
+        'type': 'mozilla::widget::LegacyJumpListLink',
+        'headers': ['/widget/windows/LegacyJumpListItem.h'],
+    },
+    {
+        'cid': '{b16656b2-5187-498f-abf4-56346126bfdb}',
+        'contract_ids': ['@mozilla.org/windows-legacyjumplistshortcut;1'],
+        'type': 'mozilla::widget::LegacyJumpListShortcut',
+        'headers': ['/widget/windows/LegacyJumpListItem.h'],
+    },
+    {
+        'cid': '{e04a55e8-fee3-4ea2-a98b-41d2621adc3c}',
+        'contract_ids': ['@mozilla.org/windows-ui-utils;1'],
+        'type': 'WindowsUIUtils',
+        'headers': ['/widget/windows/WindowsUIUtils.h'],
+    },
+    {
+        'cid': '{8b5314bc-db01-11d2-96ce-0060b0fb9956}',
+        'contract_ids': ['@mozilla.org/widget/transferable;1'],
+        'type': 'nsTransferable',
+        'headers': ['/widget/nsTransferable.h'],
+    },
+    {
+        'cid': '{948a0023-e3a7-11d2-96cf-0060b0fb9956}',
+        'contract_ids': ['@mozilla.org/widget/htmlformatconverter;1'],
+        'type': 'nsHTMLFormatConverter',
+        'headers': ['/widget/nsHTMLFormatConverter.h'],
+    },
+    {
+        'cid': '{f92e733e-33a3-4752-90e5-25801ddeaf7b}',
+        'contract_ids': ['@mozilla.org/widget/parent/dragservice;1'],
+        'type': 'nsDragService',
+        'headers': ['/widget/windows/nsDragService.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{9a0cb62b-d638-4faf-9588-ae96f5e29093}',
+        'contract_ids': ['@mozilla.org/widget/taskbar-preview-callback;1'],
+        'type': 'mozilla::widget::TaskbarPreviewCallback',
+        'headers': ['/widget/windows/TaskbarPreview.h'],
+    },
+    {
+        'name': 'GfxInfo',
+        'cid': '{d755a760-9f27-11df-0800-200c9a664242}',
+        'contract_ids': ['@mozilla.org/gfx/info;1'],
+        'type': 'mozilla::widget::GfxInfo',
+        'headers': ['/widget/windows/GfxInfo.h'],
+        'init_method': 'Init',
+        'processes': ProcessSelector.ALLOW_IN_GPU_RDD_SOCKET_AND_UTILITY_PROCESS,
+    },
+    {
+        'cid': '{e2fc3e45-c893-4b34-8f6d-b87faf65a897}',
+        'contract_ids': ['@mozilla.org/parent/filepicker;1'],
+        'type': 'nsFilePicker',
+        'headers': ['/widget/windows/nsFilePicker.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{035d92f3-3802-4cf5-87cb-1758bfc5d4da}',
+        'contract_ids': ['@mozilla.org/parent/colorpicker;1'],
+        'type': 'nsColorPicker',
+        'headers': ['/widget/windows/nsColorPicker.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{1201d357-8417-4926-a694-e6408fbedcf8}',
+        'contract_ids': ['@mozilla.org/sharepicker;1'],
+        'type': 'nsSharePicker',
+        'headers': ['/widget/windows/nsSharePicker.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{25b4efa0-7054-4787-9cd6-630efb3fe6fa}',
+        'contract_ids': ['@mozilla.org/widget/parent/clipboard;1'],
+        'interfaces': ['nsIClipboard'],
+        'type': 'nsIClipboard',
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+    {
+        'cid': '{b6e1a890-b2b8-4883-a65f-9476f6185313}',
+        'contract_ids': ['@mozilla.org/widget/systemstatusbar;1'],
+        'singleton': True,
+        'init_method': 'Init',
+        'type': 'mozilla::widget::SystemStatusBar',
+        'constructor': 'mozilla::widget::SystemStatusBar::GetAddRefedSingleton',
+        'headers': ['/widget/windows/SystemStatusBar.h'],
+        'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+    },
+]
+
+if buildconfig.substs['CC_TYPE'] == 'clang-cl':
+    Classes += [
+        {
+            'cid': '{84e11f80-ca55-11dd-ad8b-0800200c9a66}',
+            'contract_ids': ['@mozilla.org/system-alerts-service;1'],
+            'type': 'mozilla::widget::ToastNotification',
+            'headers': ['/widget/windows/ToastNotification.h'],
+            'init_method': 'Init',
+            'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        },
+        {
+            'cid': '{a46c385b-a45c-4b48-ab7c-aaed1252bb83}',
+            'contract_ids': ['@mozilla.org/windows-alert-notification;1'],
+            'type': 'mozilla::widget::WindowsAlertNotification',
+            'headers': ['/widget/windows/ToastNotification.h'],
+            'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        }
+    ]
+
+if defined('NS_PRINTING'):
+    Classes += [
+        {
+            'cid': '{d3f69889-e13a-4321-980c-a39332e21f34}',
+            'contract_ids': ['@mozilla.org/gfx/devicecontextspec;1'],
+            'type': 'nsDeviceContextSpecWin',
+            'headers': ['/widget/windows/nsDeviceContextSpecWin.h'],
+            'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        },
+        {
+            'cid': '{06beec76-a183-4d9f-85dd-085f26da565a}',
+            'contract_ids': ['@mozilla.org/widget/printdialog-service;1'],
+            'type': 'nsPrintDialogServiceWin',
+            'headers': ['/widget/windows/nsPrintDialogWin.h'],
+            'init_method': 'Init',
+            'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        },
+        {
+            'cid': '{841387c8-72e6-484b-9296-bf6eea80d58a}',
+            'contract_ids': ['@mozilla.org/gfx/printsettings-service;1'],
+            'type': 'nsPrintSettingsServiceWin',
+            'headers': ['/widget/windows/nsPrintSettingsServiceWin.h'],
+            'init_method': 'Init',
+        },
+        {
+            'cid': '{a6cf9129-15b3-11d2-932e-00805f8add32}',
+            'contract_ids': ['@mozilla.org/gfx/printerlist;1'],
+            'type': 'nsPrinterListWin',
+            'headers': ['/widget/windows/nsDeviceContextSpecWin.h'],
+            'processes': ProcessSelector.MAIN_PROCESS_ONLY,
+        },
+    ]
diff --git a/widget/windows/docs/blocklist.rst b/widget/windows/docs/blocklist.rst
new file mode 100644
index 0000000000..5450faaa1b
--- /dev/null
+++ b/widget/windows/docs/blocklist.rst
@@ -0,0 +1,347 @@
+========================
+Windows DLL Blocklisting
+========================
+
+--------
+Overview
+--------
+
+There are many applications which interact with another application, which means
+they run their code as a DLL in a different process. This technique is used, for
+example, when an antivirus software tries to monitor/block navigation to a
+malicious website, or a screen reader tries to access UI parts. If such an
+application injects their code into Firefox, and if there is a bug in their code
+running in our firefox.exe, it will emerge as Firefox’s bug even though it’s
+not.
+
+Firefox for Windows has a feature to prevent DLLs from being loaded into our
+processes. If we are aware that a particular DLL causes a problem in our
+processes such as a crash or performance degradation, we can stop the problem by
+blocking the DLL from being loaded.
+
+This blocklist is about a third-party application which runs outside Firefox but
+interacts with Firefox. For add-ons, there is `a different process
+<https://extensionworkshop.com/documentation/publish/add-ons-blocking-process/>`_.
+
+This page explains how to request to block a DLL which you think we should block
+it as well as technical details about the feature.
+
+-----------------------
+Two types of blocklists
+-----------------------
+
+There are two types of blocklists in Firefox:
+
+1. A static blocklist that is compiled in to Firefox. This consists of DLLs
+   known to cause problems with Firefox, and this blocklist cannot be disabled
+   by the user. For more information and instructions on how to add a new DLL
+   to this list, see :ref:`Process for blocking a DLL in the static blocklist
+   <how-to-block-dll-in-static-blocklist>` below.
+2. A dynamic blocklist that users can use to block DLLs that are giving them
+   problems. This was added in
+   `bug 1744362 <https://bugzilla.mozilla.org/show_bug.cgi?id=1744362>`_.
+
+The static blocklist has ways to specify if only certain versions of a DLL
+should be blocked, or only for certain Firefox processes, etc. The dynamic
+blocklist does not have this capability; if a DLL is on the list it will always
+be blocked.
+
+Regardless of which blocklist the DLL is on, if it meets the criteria for being
+blocked Firefox uses the same mechanism to block it. There are more details
+below in :ref:`How the blocklist blocks a DLL <how-the-blocklist-blocks-a-dll>`.
+
+.. _how-to-block-dll-in-static-blocklist:
+
+--------------------------------------------------
+Process for blocking a DLL in the static blocklist
+--------------------------------------------------
+
+But wait, should we really block it?
+------------------------------------
+
+Blocking a DLL with the static blocklist should be our last resort to fix a
+problem because doing it normally breaks functionality of an application which
+installed the DLL. If there is another option, we should always go for it.
+Sometimes we can safely bypass a third-party’s problem by changing our code even
+though its root cause is not on our side.
+
+When we decide to block it, we must be certain that the issue at hand is so
+great that it outweighs the user's choice to install the software, the utility
+it provides, and the vendor's freedom to distribute and control their software.
+
+How to request to block a DLL
+-----------------------------
+
+Our codebase has the file named
+`WindowsDllBlocklistDefs.in <https://searchfox.org/mozilla-central/source/toolkit/xre/dllservices/mozglue/WindowsDllBlocklistDefs.in>`_ from which our build process generates DLL blocklists as C++ header files and compiles them. To block a new DLL, you create a patch to update WindowsDllBlocklistDefs.in and land it on our codebase, following our standard development process. Moreover, you need to fill out a form specific to the DLL blockling request so that reviewers can review the impact and risk as well as the patch itself.
+
+Here are the steps:
+
+1. File `a bug
+   <https://bugzilla.mozilla.org/enter_bug.cgi?format=__default__&bug_type=defect&product=Toolkit&component=Blocklist%20Policy%20Requests&op_sys=Windows&short_desc=DLL%20block%20request%3A%20%3CDLL%20name%3E&comment=Please%20go%20through%20https%3A%2F%2Fwiki.mozilla.org%2FBlocklisting%2FDLL%20before%20filing%20a%20new%20bug.>`_
+   if it does not exist.
+2. Answer all the questions in `this questionnaire
+   <https://msmania.github.io/assets/mozilla/third-party-modules/questionnaire.txt>`_,
+   and attach it to the bug as a plaintext.
+3. Make a patch and start a code review via Phabricator as usual.
+
+How to edit WindowsDllBlocklistDefs.in
+--------------------------------------
+
+WindowsDllBlocklistDefs.in defines several variables as a Python Array. When you
+add a new entry in the blocklists, you pick one of the variables and add an
+entry in the following syntax:
+
+Syntax
+******
+
+::
+
+ Variable += [
+ ...
+     # One-liner comment including a bug number
+     EntryType(Name, Version, Flags),
+ ...
+ ]
+
+Parameters
+**********
+
++-----------+--------------------------------------------------------------------------------+
+| Parameter | Value                                                                          |
++===========+================================================================================+
+| Variable  | ALL_PROCESSES \| BROWSER_PROCESS \| CHILD_PROCESSES \| GMPLUGIN_PROCESSES \|   |
+|           | GPU_PROCESSES \| SOCKET_PROCESSES \| UTILITY_PROCESSES                         |
++-----------+--------------------------------------------------------------------------------+
+| EntryType | DllBlocklistEntry \| A11yBlocklistEntry \| RedirectToNoOpEntryPoint            |
++-----------+--------------------------------------------------------------------------------+
+| Name      | A case-insensitive string representing a DLL's filename to block               |
++-----------+--------------------------------------------------------------------------------+
+| Version   | One of the following formats:                                                  |
+|           |                                                                                |
+|           |   - ALL_VERSIONS \| UNVERSIONED                                                |
+|           |   - A tuple consisting of four digits                                          |
+|           |   - A 32-bit integer representing a Unix timestamp with PETimeStamp            |
++-----------+--------------------------------------------------------------------------------+
+
+Variable
+********
+
+Choose one of the following predefined variables.
+
+- **ALL_PROCESSES**: DLLs defined here are blocked in BROWSER_PROCESS +
+  CHILD_PROCESSES
+- **BROWSER_PROCESS**: DLLs defined here are blocked in the browser process
+- **CHILD_PROCESSES**: DLLs defined here are blocked in non-browser processes
+- **GMPLUGIN_PROCESSES**: DLLs defined here are blocked in GMPlugin processes
+- **GPU_PROCESSES**: DLLs defined here are blocked in GPU processes
+- **SOCKET_PROCESSES**: DLLs defined here are blocked in socket processes
+- **UTILITY_PROCESSES**: DLLs defined here are blocked in utility processes
+
+EntryType
+*********
+Choose one of the following predefined EntryTypes.
+
+- **DllBlocklistEntry**: Use this EntryType unless your case matches the other
+  EntryTypes.
+- **A11yBlocklistEntry**: If you want to block a module only when it’s loaded by
+  an accessibility application such as a screen reader, you can use this
+  EntryType.
+- **RedirectToNoOpEntryPoint**: If a modules is injected via Import Directory
+  Table, adding the module as DllBlocklistEntry breaks process launch, meaning
+  DllBlocklistEntry is not an option. You can use RedirectToNoOpEntryPoint
+  instead.
+
+Name
+****
+A case-insensitive string representing a DLL's filename to block. Don’t include a directory name.
+
+Version
+*******
+
+A maximum version to be blocked. If you specify a value, a module with the
+specified version, older versions, and a module with no version are blocked.
+
+| If you want to block a module regardless of its version, use ALL_VERSIONS.
+| If you want to block a module with no version, use UNVERSIONED.
+
+
+To specify a version, you can use either of the following formats:
+
+- | A tuple consisting of four digits. This is compared to the version that is embedded in a DLL as a version resource.
+  | Example: (1, 2, 3, 4)
+- | A 32-bit integer representing a Unix timestamp with PETimeStamp. This is compared to an integer of IMAGE_FILE_HEADER::TimeDateStamp.
+  | Example: PETimeStamp(0x12345678)
+
+
+-----------------
+Technical details
+-----------------
+
+.. _how-the-blocklist-blocks-a-dll:
+
+How the blocklist blocks a DLL
+------------------------------
+
+Briefly speaking, we make ntdll!NtMapViewOfSection return
+``STATUS_ACCESS_DENIED`` if a given module is on the blocklist, thereby a
+third-party’s code, or even Firefox’s legitimate code, which tries to load a DLL
+in our processes in any way such as LoadLibrary API fails and receives an
+access-denied error.
+
+Cases where we should not block a module
+----------------------------------------
+
+As our blocklist works as explained above, there are the cases where we should not block a module.
+
+- | A module is loaded via `Import Directory Table <https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#import-directory-table>`_
+  | Blocking this type of module blocks even a process from launching. You may be able to block this type of module with RedirectToNoOpEntryPoint.
+- | A module is loaded as a `Layered Service Provider <https://docs.microsoft.com/en-us/windows/win32/winsock/categorizing-layered-service-providers-and-applications>`_
+  | Blocking this type of module on Windows 8 or newer breaks networking. Blocking a LSP on Windows 7 is ok.
+
+(we used to have to avoid blocking modules loaded via a
+`Window hook <https://docs.microsoft.com/en-us/windows/win32/winmsg/hooks>`_ because blocking this type of
+module would cause repetitive attempts to load a module, resulting in slow performance
+like `Bug 1633718 <https://bugzilla.mozilla.org/show_bug.cgi?id=1633718>`_, but this should be fixed
+as of `Bug 1823412 <https://bugzilla.mozilla.org/show_bug.cgi?id=1823412>`_.)
+
+Third-party-module ping
+-----------------------
+
+We’re collecting the :ref:`third-party-module ping <third-party-modules-ping>`
+which captures a moment when a third-party module is loaded into the
+Browser/Tab/RDD process. As it’s asked in the request form, it’s important to
+check the third-party-module ping and see whether a module we want to block
+appears in the ping or not. If it appears, you may be able to know how a module
+is loaded by looking at a callstack in the ping.
+
+How to view callstacks in the ping
+**********************************
+
+1. You can run a query on BigQuery console or STMO.  (BigQuery console is much
+   faster and can handle larger data.)
+
+   - BigQuery console (visit
+     `here <https://docs.telemetry.mozilla.org/cookbooks/bigquery.html#gcp-bigquery-console>`_
+     to request access): https://console.cloud.google.com/bigquery
+   - STMO: https://sql.telemetry.mozilla.org/
+
+2. Make your own query based on `this template
+   <https://msmania.github.io/assets/mozilla/third-party-modules/query-template.txt>`_.
+3. Run the query.
+4. Save the result as a JSON file.
+
+   - In BigQuery console, click [SAVE RESULTS] and choose [JSON (local file)].
+   - In STMO, click [...] at the right-top corner and select [Show API Key],
+     then you can download a JSON from a URL shown in the [Results in JSON format].
+
+5. | Go to https://msmania.github.io/assets/mozilla/third-party-modules/
+   |   (A temporal link. Need to find a permanent place.)
+6. Click [Upload JSON] and select the file you saved at the step 4.
+7. Click a row in the table to view a callstack
+
+
+How to see the versions of a specific module in the ping
+********************************************************
+
+You can use `this template query
+<https://msmania.github.io/assets/mozilla/third-party-modules/query-groupby-template.txt>`_
+to query which versions of a specific module are captured in the ping. This
+tells the product versions which are actively used including the crashing
+versions and the working versions.
+
+You can also get the crashing versions by querying the crash reports or the
+Socorro table. Having two version lists, you can decide whether you can specify
+the Version parameter in a blocklist entry.
+
+Initialization
+--------------
+
+In order to have the most effective blocking of DLLs, the blocklist is
+initialized very early during browser startup. If the :ref:`launcher process
+<launcher-process>` is available, the steps are:
+
+- Launcher process loads dynamic blocklist from disk (see
+  `DynamicBlocklist::LoadFile()
+  <https://searchfox.org/mozilla-central/search?q=DynamicBlocklist%3A%3ALoadFile&path=&case=false&regexp=false>`_)
+- Launcher process puts dynamic blocklist data in shared section (see
+  `SharedSection::AddBlocklist()
+  <https://searchfox.org/mozilla-central/search?q=SharedSection%3A%3AAddBlocklist&path=&case=false&regexp=false>`_)
+- Launcher process creates the browser process in a suspended mode, sets up its
+  dynamic blocklist, then starts it. (see `LauncherMain()
+  <https://searchfox.org/mozilla-central/search?q=LauncherMain&path=&case=false&regexp=false>`_)
+
+  - This is so (ideally) no DLLs can be injected before the blocklist is set up.
+
+If the launcher process is not available, a different blocklist is used, defined
+in `mozglue/WindowsDllBlocklist.cpp
+<https://searchfox.org/mozilla-central/source/toolkit/xre/dllservices/mozglue/WindowsDllBlocklist.cpp>`_.
+This code does not currently support the dynamic blocklist. This is intended to
+only be used in testing and other non-deployed scenarios, so this shouldn't be
+a problem for users.
+
+Note that the mozglue blocklist also has a feature to block threads that start
+in ``LoadLibrary`` and variants. This code is currently only turned on in
+Nightly builds because it breaks some third-party DLP products.
+
+Dynamic blocklist file location
+-------------------------------
+
+Because the blocklist is loaded so early during startup, we don't have access to
+what profile is going to be loaded, so the blocklist file can't be stored there.
+Instead, by default the blocklist file is stored in the Windows user's roaming
+app data directory, specifically
+
+``<Roaming AppData directory>\Mozilla\Firefox\blocklist-<install hash>``
+
+Note that the install hash here is what is returned by `GetInstallHash()
+<https://searchfox.org/mozilla-central/source/toolkit/mozapps/update/common/commonupdatedir.cpp#404>`_,
+and is suitable for uniquely identifying the particular Firefox installation
+that is running.
+
+On first launch, this location will be written to the registry, and can be
+overriden by setting that key to a different file location. The registry key is
+``HKEY_CURRENT_USER\Software\Mozilla\Firefox\Launcher``, and the name is the
+full path to firefox.exe with "\|Blocklist" appended. This code is in
+`LauncherRegistryInfo
+<https://searchfox.org/mozilla-central/source/toolkit/xre/LauncherRegistryInfo.cpp>`_.
+
+Adding to and removing from the dynamic blocklist
+-------------------------------------------------
+
+Users can add or remove DLLs from the dynamic blocklist by navigating to
+``about:third-party``, finding the entry for the DLL they are interested in, and
+clicking on the dash icon. They will then be prompted to restart the browser, as
+the change will only take effect after the browser restarts.
+
+Disabling the dynamic blocklist
+-------------------------------
+
+It is possible that users can get Firefox into a bad state by putting a DLL on
+the dynamic blocklist. One possibility is that the user blocks only one of a set
+of DLLs that interact, which could make Firefox behave in unpredictable ways or
+crash.
+
+By launching Firefox with ``--disableDynamicBlocklist``\, the dynamic blocklist
+will be loaded but not used to block DLLs. This lets the user go to
+``about:third-party`` and attempt to fix the problem by unblocking or blocking
+DLLs.
+
+Similarly, in safe mode the dynamic blocklist is also disabled.
+
+Enterprise policy
+-----------------
+
+The dynamic blocklist can be disabled by setting a registry key at
+``HKEY_CURRENT_USER\Software\Policies\Mozilla\Firefox`` with a name of
+DisableThirdPartyModuleBlocking and a DWORD value of 1. This will have the
+effect of not loading the dynamic blocklist, and no icons will show up in
+``about:third-party`` to allow blocking DLLs.
+
+-------
+Contact
+-------
+
+Any questions or feedback are welcome!
+
+**Matrix**: `#hardening <https://app.element.io/#/room/#hardening:mozilla.org>`_
diff --git a/widget/windows/docs/index.rst b/widget/windows/docs/index.rst
new file mode 100644
index 0000000000..9a24cb9cdb
--- /dev/null
+++ b/widget/windows/docs/index.rst
@@ -0,0 +1,9 @@
+==================
+Firefox on Windows
+==================
+
+.. toctree::
+   :maxdepth: 2
+
+   blocklist
+   windows-pointing-device/index
diff --git a/widget/windows/docs/windows-pointing-device/apple_vision.jpg b/widget/windows/docs/windows-pointing-device/apple_vision.jpg
new file mode 100644
index 0000000000..9515f4d4fb
--- /dev/null
+++ b/widget/windows/docs/windows-pointing-device/apple_vision.jpg
diff --git a/widget/windows/docs/windows-pointing-device/apple_vision_user.webp b/widget/windows/docs/windows-pointing-device/apple_vision_user.webp
new file mode 100644
index 0000000000..64f8afc0e5
--- /dev/null
+++ b/widget/windows/docs/windows-pointing-device/apple_vision_user.webp
diff --git a/widget/windows/docs/windows-pointing-device/index.rst b/widget/windows/docs/windows-pointing-device/index.rst
new file mode 100644
index 0000000000..eda552b3dd
--- /dev/null
+++ b/widget/windows/docs/windows-pointing-device/index.rst
@@ -0,0 +1,1384 @@
+################################################################################
+Windows Pointing Device Support in Firefox
+################################################################################
+
+.. contents:: Table of Contents
+    :depth: 4
+
+================================================================================
+Introduction
+================================================================================
+
+This document is intended to provide the reader with a quick primer and/or
+refresher on pointing devices and the various operating system APIs, user
+experience guidelines, and Web standards that contribute to the way Firefox
+handles input devices on Microsoft Windows.
+
+The documentation for these things is scattered across the web and has varying
+levels of detail and completeness; some of it is missing or ambiguous and was
+only determined experimentally or by reading about other people's experiences
+through forum posts. An explicit goal of this document is to gather this
+information into a cohesive picture.
+
+We will then discuss the ways in which Firefox currently (as of early 2023)
+produces incorrect or suboptimal behavior when implementing those standards
+and guidelines.
+
+Finally, we will raise some thoughts and questions to spark discussion on how
+we might improve the situation and handle corner cases. Some of
+these issues are intrinsically "opinion based" or "policy based", so clear
+direction on these is desirable before engineering effort is invested into
+reimplementation.
+
+
+================================================================================
+Motivation
+================================================================================
+
+A quick look at the `pile of defects  <https://bugzilla.mozilla.orgbuglist.cgi?query_format=advanced&status_whiteboard=%5Bwin%3Atouch%5D&list_id=16586149&status_whiteboard_type=allwordssubstr>`__
+on *bugzilla.mozilla.org* marked with *[win:touch]* will show anyone that
+Firefox's input stack for pointer devices has issues, but the bugs recorded
+there don't begin to capture the full range of unreported glitches and
+difficult-to-reproduce hiccups that users run into while using touchscreen
+hardware and pen digitizers on Firefox, nor does it capture the ways that
+Firefox misbehaves according to various W3C standards that are (luckily) either
+rarely used or worked around in web apps (and thus go undetected or
+unreported).
+
+These bugs primarily manifest in a few ways that will each be discussed in
+their own section:
+
+1.  Firefox failing to return the proper values for the ``pointer``,
+    ``any-pointer``, ``hover``, and ``any-hover`` CSS Media Queries
+
+2.  Firefox failing to fire the correct pointer-related DOM events at the
+    correct time (or at all)
+
+3.  Firefox's inconsistent handling of touch-related gestures like scrolling,
+    where certain machines (like the Surface Pro) fail to meet the expected
+    behavior of scrolling inertia and overscroll. This leads to a weird touch
+    experience where the page comes to a choppy, dead-stop when using
+    single-finger scrolling
+
+
+It's worth noting that Firefox is not alone in having these types of issues,
+and that handling input devices is a notoriously difficult task for many
+applications; even a substantial amount of Microsoft's own software has trouble
+navigating this minefield on their own Microsoft Surface devices. Defects are
+instigated by a combination of the *intrinsic complexity* of the problem domain
+and the *accidential complexity* introduced by device vendors and Windows
+itself.
+
+The *intrinsic complexity* comes from the simple fact that human-machine
+interaction is difficult. A person must attempt to convey complex
+and abstract goals through a series of simple movements involving a few pieces
+of physical hardware. The devices can send signals that are unclear
+or even contradictory, and the software must decide how to handle
+this.
+
+As a trivial example, every software engineer that's ever written
+page scrolling logic has to answer the question, "What should my
+program do if the user hits 'Page Up' and 'Page Down' at the same time?".
+While it may seem obvious that the answer is "Do nothing.", naively-written
+keyboard input logic might assume the two are mutually-exclusive and only
+process whichever key is handled first in program order.
+
+Occasionally, a new device will be invented that doesn't obviously map to
+existing abstractions and input pipelines. There will be a period of time where
+applications will want to support the new device, but it won't be well
+understood by either the application developers nor the device vendor
+themselves what ideal integration would look like. The new Apple Vision VR
+headset is such a device; traditional VR headsets have used controllers to
+point at things, but Apple insists that the entire thing should be done using
+only hand tracking and eye tracking. Developers of VR video games and other
+apps (like Firefox) will inevitably make many mistakes on the road to
+supporting this new headset.
+
+A major source of defect-causing *accidental complexity* is the lack of clear
+expectations and documentation from Microsoft for apps (like Firefox) that are
+not using their Universal Windows Platform (UWP). The Microsoft Developer
+Network (MSDN) mentions concepts like inertia, overscroll, elastic bounce,
+single-finger panning, etc., but the solution is presented in the context
+of UWP, and the solution for non-UWP apps is either unclear or undocumented.
+
+Adding to this complexity is the fact that Windows itself has gone through
+several iterations of input APIs for different classes of devices, and
+these APIs interact with each other in ways that are surprising or
+unintuitive. Again, the advice given on MSDN pertains to UWP apps, and the
+documentation about the newer "pointer" based window messages is
+a mix of incomplete and inaccurate.
+
+Finally, individual input devices have bugs in their driver software that
+would disrupt even applications that are using the Windows input APIs perfectly.
+Handling all of these deviations is impossible and would result in fragile,
+unmaintainable code, but Firefox inevitably has to work around common ones to
+avoid alienating large portions of the userbase.
+
+
+================================================================================
+Technical Background
+================================================================================
+
+
+A Quick Primer on Pointing Devices
+======================================
+
+
+Traditionally, web browsers were designed to accommodate computer mice and
+devices that behave in a similar way, like trackballs and touchpads on
+laptops. Generally, it was assumed that there would be one such device attached
+to the computer, and it would be used to control a hovering "cursor" whose
+movements would be changed by relative movement of the physical input device.
+
+However, modern computers can be controlled using a variety of different
+pointing devices, all with different characteristics. Many allow
+multiple concurrent targets to be pointed at and have multiple sensors,
+buttons, and other actuators.
+
+For example, the screen of the Microsoft Surface Pro has dual capabilities
+of being a touch sensor and a digitizer for a tablet pen. When being used as a
+workstation, it's not uncommon for a user to also connect the "keyboard +
+touchpad" cover and a mouse (via USB or Bluetooth) to provide the more
+productivity-oriented "keyboard and mouse" setup. In that configuration, there
+are 4 pointer devices connected to the machine simultaneously: a touch screen,
+a pen digitizer, a touchpad, and a mouse.
+
+The next section will give a quick overview of common pointing devices.
+Many will be familiar to the reader, but they are still mentioned to establish
+common terminology and to avoid making assumptions about familiarity with every
+input device.
+
+
+Common Pointing Devices
+---------------------------
+
+Here are some descriptions of a few pointing device types that demonstrate
+the diversity of hardware:
+
+**Touchscreen**
+
+    A touchscreen is a computer display that is able to sense the
+    location of (possibly-multiple) fingers (or stylus) making contact with its
+    surface. Software can then respond to the touches by changing the displayed
+    objects quickly, giving the user a sense of actually physically manipulating
+    them on screen with their hands.
+
+    .. image:: touchscreen.jpg
+        :width: 25%
+
+
+**Digitizing Tablet + Pen Stylus**
+
+    These advanced pointing devices tend to
+    exist in two forms: as an external sensing "pad" that can be plugged into a
+    computer and sits on a desk or in someone's lap, or as a sensor built right
+    into a computer display. Both use a "stylus", which is a pen-shaped
+    electronic device that is detectable by the surface. Common features
+    include the ability to distinguish proximity to the surface ("hovering")
+    versus actual contact, pressure sensitivity, angle/tilt detection, multiple
+    "ends" such as a tip and an eraser, and one-or-more buttons/switch
+    actuators.
+
+    .. image:: wacom_tablet.png
+        :width: 25%
+
+
+**Joystick/Pointer Stick**
+
+    Pointer sticks are most often seen in laptop
+    computers made by IBM/Lenovo, where they exist as a little red nub located
+    between the G, H, and B keys on a standard QWERTY keyboard. They function
+    similarly to the analog sticks on a game controller -- The user displaces
+    the stick from its center position, and that is interpreted as a relative
+    direction to move the on-screen cursor. A greater displacement from center
+    is interpreted as increased velocity of movement.
+
+    .. image:: trackpoint.jpg
+        :width: 25%
+
+
+**Touchpad**
+
+    A touchpad is a rectangular surface (often found on laptop
+    computers) that detects touch and motion of a finger and moves an on-screen
+    cursor relative to the motion. Modern touchpads often support multiple
+    touches simultaneously, and therefore offer functionality that is quite
+    similar to a touchscreen, albeit with different movement semantics because
+    of their physical separation from the screen (discussed below).
+
+    .. image:: touchpad.jpg
+        :width: 25%
+
+
+**VR Controllers**
+
+    VR controllers (and other similar devices like the
+    Wiimote from the Nintendo Wii) allow users to point at objects in a
+    three-dimensional virtual world by moving a real-world controller and
+    "projecting" the controller's position into the virtual space. They often
+    also include sensors to detect the yaw, pitch, and roll of the sensors.
+    There are often other inputs in the controller device, like analog sticks
+    and buttons.
+
+    .. image:: vrcontroller.jpg
+        :width: 25%
+
+
+**Hand Tracking**
+
+    Devices like the Apple Vision (introduced during the
+    time this document was being written) and (to a lesser extent) the Meta
+    Quest have the ability to track the wearer's hand and directly interpret
+    gestures and movements as input. As the human hand can assume a staggering
+    number of orientations and configurations, a finite list of specific shapes
+    and movements must be identified and labelled to allow for clear
+    software-user interaction.
+
+    .. image:: apple_vision_user.webp
+        :width: 25%
+
+    .. image:: apple_vision.jpg
+        :width: 25%
+
+
+**Mouse**
+
+    A pointing device that needs no introduction. Moving a physical
+    clam-shaped device across a surface translates to relative movement of a
+    cursor on screen.
+
+    .. image:: mouse.jpg
+        :width: 25%
+
+
+The Buxton Three-State Model
+-------------------------------
+
+
+Bill Buxton, an early pioneer in the field of human-computer interaction,
+came up with a three-state model for pointing devices; a device can be
+"Out of Range", "Tracking", or "Dragging". Not all devices support all three
+states, and some devices have multiple actuators that can have the three-state
+model individually applied.
+
+.. mermaid::
+
+    stateDiagram-v2
+        direction LR
+        state "State 0" as s0
+        state "State 1" as s1
+        state "State 2" as s2
+        s0 --> s0 : Out Of Range
+        s1 --> s1 : Tracking
+        s2 --> s2 : Dragging
+        s0 --> s1 : Stylus On
+        s1 --> s0 : Stylus Lift
+        s1 --> s2 : Tip Switch Close
+        s2 --> s1 : Tip Switch Open
+
+
+For demonstration, here is the model applied to a few devices:
+
+**Computer Mouse**
+
+    A mouse is never in the "Out of Range" state. Even though it can technically
+    be lifted off its surface, the mouse does not report this as a separate
+    condition; instead, it behaves as-if it is stationary until it can once
+    again sense the surface moving underneath.
+
+    The remaining two states apply to each button individually; when a button is
+    not being pressed, the mouse is considered in the "tracking" state with
+    respect to that button. When a button is held down, the mouse is "dragging"
+    with respect to that button. A "click" is simply considered a zero-length
+    drag under this model.
+
+    In the case of a two-button mouse, this means that the mouse can be in a
+    total of 4 different states: tracking, left button dragging, right button
+    dragging, and two-button dragging. In practice, very little software
+    actually does anything meaningful with two-button dragging.
+
+**Touch Screen**
+
+    Applying the model to a touch screen, one can observe that current hardware
+    has no way to sense that a finger that is "hovering, but not quite making
+    contact with the screen". This means that the "Tracking" state can be ruled
+    out, leaving only the "Out of Range" and "Dragging" states. Since many touch
+    screens can support multiple fingers touching the screen concurrently, and
+    each finger can be in one of two states, there are potentially 2^N different
+    "states" that a touchscreen can be in. Windows assigns meaning to many two,
+    three, and four-finger gestures.
+
+**Tablet Digitizer**
+
+    A tablet digitizer supports all three states: when the stylus is far away
+    from the surface, it is considered "out of range"; when it is located
+    slightly above the surface, it is "tracking"; and when it is making contact
+    with the surface, it is "dragging".
+
+The W3C standards for pointing devices are based on this three-state model, but
+applied to each individual web element instead of the entire system. This
+makes things like "Out-of-Range" possible for the mouse, since it can be
+out of range of a web element.
+
+The W3C uses the terms "over" and "out" to convey the transition between
+"out-of-range" and "tracking" (which the W3C calls "hover"), and the terms
+"down" and "up" convey the transition between "tracking" and "dragging".
+
+The standard also address some of the known shortcomings of the model to
+improve portability and consistency; these improvements will be discussed more
+below.
+
+The Windows Pointer API is *supposedly* based around this model,
+but unfortunately real-world testing shows that the model is not followed
+very consistently with respect to the actual signals sent to the application.
+
+
+Gestures
+=====================================
+
+
+In contrast to the sort-of "anything goes" UI designs of the past,
+modern operating systems like Windows, Mac OS X, iOS, Android, and even
+modern Linux DEs have an "opinionated" idea of how user interaction
+should behave across all apps on the platform (the so-called "look and feel"
+of the operating system).
+
+Users expect gestures like swipes, pinches, and taps to act the same way
+across all apps for a given operating system, and they expect things like
+on-screen keyboards or handwriting recognition to pop up in certain contexts.
+Failing to meet those expectations makes an app look less polished, and
+(especially as far as accessibility is concerned) it frustrates the user
+and makes it more difficult for them to interact with the app.
+
+Microsoft defines guidelines for various behaviours that Windows applications
+should ideally adhere to in the `Input and Interactions <https://learn.microsoft.com/en-us/windows/apps/design/input/>`__
+section on MSDN. Some of these are summarized quickly below:
+
+**Drag and Drop**
+
+    Drag and drop allows a user to transfer data from one application to
+    another. The gesture begins when a pointer device moves into the "Dragging"
+    state over top of a UI element, usually as a result of holding down a mouse
+    button or pressing a finger on a touchscreen. The user moves the pointer
+    over top of the receiver of the data, and then ends the gesture by releasing
+    the mouse button or lifting their finger off the touchscreen. Window
+    interprets this transition out of the "Dragging" state as permission to
+    initiate the data transfer.
+
+    Firefox has supported Drag and Drop for a very long time, so it will not be
+    discussed further.
+
+
+**Pan and Zoom**
+
+    When using touchscreens (and multi-touch touchpads), users expect to be able
+    to cause the viewport to "pan" left/right/up/down by pressing two fingers on
+    the screen (creating two pointers in "Dragging" state) and moving their
+    fingers in the direction of movement. When they are done, they can release
+    both fingers (changing both pointers to "Out of Bounds").
+
+    A zoom can be signalled by moving the two fingers apart or together
+    in a "pinch" or "reverse pinch" gesture.
+
+
+**Single Pointer Panning**
+
+    Applications that are based on a UI model of the user interacting with a
+    "page" often allow a single pointer "Dragging" over the viewport to cause
+    the viewport to pan, similarly to the two-finger panning discussed in the
+    previous section.
+
+    Note that this gesture is not as universal as two-finger panning is -- as a
+    counterexample, graphics programs tend to treat one-finger dragging as
+    object manipulation and two-finger dragging as viewport panning.
+
+
+**Inertia**
+
+    When a user is done panning, they may lift their finger/pen off the screen
+    while the viewport is still in motion. Users expect that the page will
+    continue to move for a little while, as-if the user had "tossed" the page
+    when they let go. Effectively, the page behaves as though it has "momentum"
+    that needs to be gradually lost before the page comes to a full stop.
+
+    Modern operating systems provide this behavior via their various native
+    widget toolkits, and the curve that objects follow as they slow to a stop
+    are different across OSes. In that way, they can be considered part of the
+    unique "look and feel" of the OS. Users expect the scrolling of pages in
+    their web browser to behave this way, and so when Firefox fails to provide
+    this behavior it can be jarring.
+
+
+**Overscroll and Elastic Bounce**
+
+    When a user is panning the page and reaches the outer edges, Microsoft
+    recommends that the app should begin an "elastic bounce" animation, where
+    the page will allow the user to scroll past the end ("overscroll"),
+    show empty space underneath the page, and then sort of "snap back" like a
+    rubber band that's been stretched and then released.  You can see a
+    demonstration in `this article <https://www.windowslatest.com/2020/05/21/microsoft-is-adding-elastic-scrolling-to-chrome-on-windows-10/>`__,
+    which discusses Microsoft adding it to Chromium.
+
+
+History of Web Standards and Windows APIs
+===========================================
+
+The World-Wide Web Consortium (W3C) and the Web Hypertext Application
+Technology Working Group (WHATWG) manage the standards that detail the
+interface between a user agent (like Firefox) and applications designed to run
+on the Web Platform. The user agent, in turn, must rely on the operating system
+(Windows, in this case) to provide the necessary APIs to implement the
+standards required by the Web Platform.
+
+As a result of that relationship, a Web Standard is unlikely to be created
+until all widely-used operating systems provide the required APIs. That allows
+us to build a linear timeline with a predictable pattern: a new type of device
+becomes popular, the APIs to support it are introduced into operating systems,
+and eventually a cross-platform standard is introduced into the Web Platform.
+
+The following sections detail the history of input devices supported by
+Windows and the Web Platform:
+
+
+**1985 - Computer Mouse Support (Windows 1.0)**
+
+    The first version of Windows (1985) supported a computer mouse. Support
+    for other input devices is not well-documented, but probably non-existant.
+
+
+**1991 - Third-Party De-facto Pen Support (Wintab)**
+
+    In the late 80s and early 90s, any tablet pen hardware vendor that wanted
+    to support Windows would need to write a device driver and design a
+    proprietary user-mode API to expose the device to user applications. In
+    turn, application developers would have to write and maintain code to
+    support the APIs of every relevant device vendor.
+
+    In 1991, a company named LCS/Telegraphics released an API for Windows
+    called "Wintab", which was designed in collaboration with hardware and
+    software vendors to define a general API that could be targetted by
+    device drivers and applications.
+
+    It would take Microsoft more than a decade to include first-party support
+    for tablet pens in Windows, which allowed Wintab to become the de-facto
+    standard for pen support on Windows. The Wintab API continues to be
+    supported by virtually all artist tablets to this day. Notable companies
+    include Wacom, Huion, XP-Pen, etc.
+
+
+**1992 - Early Windows Pen Support (Windows for Pen Computing)**
+
+    The earliest Windows operating system to support non-mouse pointing devices
+    was Windows 3.1 with the "Windows for Pen Computing" add-on (1992).
+    (`For the curious <https://socket3.wordpress.com/2019/07/31/windows-for-pen-computing-1-0/>`__,
+    and I'm certain `this book <https://www.amazon.com/Microsoft-Windows-Pen-Computing-Programmers/dp/1556154690>`__
+    is a must-read!). Pen support was mostly implemented by translating actions
+    into the existing ``WM_MOUSExxx`` messages, but also "upgraded" any
+    application's ``EDIT`` controls into ``HEDIT`` controls, which looked the
+    same but were capable of being handwritten into using a pen. This was not
+    very user-friendly, as the controls stayed the same size and the UI was not
+    adapted to the input method. This add-on never achieved much popularity.
+
+    It is not documented whether Netscape Navigator (the ancestor of Mozilla
+    Firefox) supported this add-on or not, but there is no trace of it in modern
+    Firefox code.
+
+
+**1995 - Introduction of JavaScript and Mouse Events (De-facto Web Standard)**
+
+    The introduction of JavaScript in 1995 by Netscape Communications added a
+    programmable, event-driven scripting environment to the Web Platform.
+    Browser vendors quickly added the ability for scripts to listen for and
+    react to mouse events. These are the well-known events like ``mouseover``,
+    ``mouseenter``, ``mousedown``, etc. that are ubiquitous on the web, and are
+    known by basically anyone who has ever written front-end JavaScript.
+
+    This ubiquity created a de-facto standard for mouse input, which would
+    eventually be formally standardized by the W3C in the HTML Living Standard
+    in 2001.
+
+    The Mouse Event APIs assume that the computer has one single pointing device
+    which is always present, has a single cursor capable of "hovering" over an
+    element, and has between one and three buttons.
+
+    When support for other pointing devices like touchscreen and pen first
+    became available in operating systems, it was exposed to the web by
+    interpreting user actions into equivalent mouse events. Unfortunately, this
+    is unable to handle multiple concurrent pointers (like one would get from
+    multitouch screens) or report the kind of rich information a pen digitizer
+    can provide, like tilt angle, pressure, etc. This eventually lead the W3C
+    to develop the new "Touch Events" standard to expose touch functionality,
+    and eventually the "Pointer Events" to expose more of the rich information
+    provided by pens.
+
+
+**2005 - Mainstream Pen Support (Windows XP Tablet PC Edition)**
+
+    It was the release of Windows XP Tablet PC Edition (2005) that allowed
+    Windows applications to directly support tablet pens by using the new COM
+    "`Windows Tablet PC <https://learn.microsoft.com/en-us/windows/win32/tablet/tablet-pc-development-guide>`__"
+    APIs, most of which are provided through the main `InkCollector <https://learn.microsoft.com/en-us/windows/win32/tablet/inkcollector-class>`__
+    class. The ``InkCollector`` functionality would eventually be "mainlined"
+    into Windows XP Professional Service Pack 2, and continues to exist in
+    modern Windows releases.
+
+    The Tablet PC APIs consist of a large group of COM objects that work
+    together to facilitate enumerating attached pens, detecting pen movement and
+    pen strokes, and analyzing them to provide:
+
+    1.  **Cursor Movement**: translates the movements of the pen into the
+        standard mouse events that applications expect from mouse cursor
+        movement, namely ``WM_NCHITTEST``, ``WM_SETCURSOR`` and
+        ``WM_MOUSEMOVE``.
+
+    2.  **Gesture Recognition**: detects common user actions, like "tap",
+        "double-tap", "press-and-hold", and "drag". The `InkCollector` delivers
+        these events via COM `SystemGesture <https://learn.microsoft.com/en-us/windows/win32/tablet/inkcollector-systemgesture>`__
+        events using the `InkSystemGesture <https://learn.microsoft.com/en-us/windows/win32/api/msinkaut/ne-msinkaut-inksystemgesture>`__
+        enumeration. It will also translate them into common Win32 messages; for
+        example, a "drag" gesture would be translated into a ``WM_LBUTTONDOWN``
+        message, several ``WM_MOUSEMOVE`` messages, and finally a
+        ``WM_LBUTTONUP`` message.
+
+        An application that is using ``InkCollector`` will receive both types of
+        messages: traditional mouse input through the Win32 message queue, and
+        "Tablet PC API" events through COM callbacks. It is up to the
+        application to determine which events matter to it in a given context,
+        as the two types of events are not guaranteed by Microsoft to correspond
+        in any predictable way.
+
+    3.  **Shape and Text Recognition**: allows the app to
+        recognize letters, numbers, punctuation, and other `common shapes <https://learn.microsoft.com/en-us/windows/win32/api/msinkaut/ne-msinkaut-inkapplicationgesture>`__
+        the user might make using their pen. Supported shapes include circles,
+        squares, arrows, and motions like "scratch out" to correct a misspelled
+        word. Custom recognizers exist that allow recognition of other symbols,
+        like music notes or mathematical notation.
+
+    4.  **Flick Recognition**: allows the user to invoke actions via quick,
+        linear motions that are recognized by Windows and sent to the app as
+        ``WM_TABLET_FLICK`` messages. The app can choose to handle the window
+        message or pass it on to the default window procedure, which will
+        translate it to scrolling messages or mouse messages.
+
+        For example, a quick upward 'flick' corresponds to "Page up", and
+        a quick sideways flick in a web browser would be "back". Flicks were
+        never widely used by Windows apps, and they may have been removed in
+        more recent versions of Windows, as the existing Control Panel menus
+        for configuring them seem to no longer exist as of Windows 10 22H2.
+
+
+    Firefox does not appear to have ever used these APIs to allow tablet pen
+    input, with the exception of `one piece of code <https://searchfox.org/mozilla-central/rev/e6cb503ac22402421186e7488d4250cc1c5fecab/widget/windows/InkCollector.cpp>`__
+    to detect when the pen leaves the Firefox window to solve
+    `Bug 1016232 <https://bugzilla.mozilla.org/show_bug.cgi?id=1016232>`__.
+
+
+**2009 - Touch Support: WM_GESTURE (Windows 7)**
+
+    While attempts were made with the release of Windows Vista (2007) to support
+    touchscreens through the existing tablet APIs, it was ultimately the release
+    of Windows 7 (2009) that brought first-class support for Touchscreen devices
+    to Windows with new Win32 APIs and two main window messages: ``WM_TOUCH``
+    and ``WM_GESTURE``.
+
+    These two messages are mutually-exclusive, and all applications are
+    initially set to receive only ``WM_GESTURE`` messages. Under this
+    configuration, Windows will attempt to recognize specific movements on a
+    touch digitizer and post "gesture" messages to the application's message
+    queue. These gestures are similar to (but, somewhat-confusingly, not
+    identical to) the gestures provided by the "Windows Tablet PC" APIs
+    mentioned above. The main gesture messages are: zoom, pan, rotate,
+    two-finger-tap, and press-and-tap (one finger presses, another finger
+    quickly taps the screen).
+
+    In contrast to the behavior of the ``InkCollector`` APIs, which will send
+    both gesture events and translated mouse messages, the ``WM_GESTURE``
+    message is truly "upstream" of the translated mouse messages; the translated
+    mouse messages will only be generated if the application forwards the
+    ``WM_GESTURE`` message to the default window procedure. This makes
+    programming against this API simpler than the ``InkCollector`` API, as
+    there is no need to state-fully "remember" that an action has already been
+    serviced by one codepath and needs to be ignored by the other.
+
+    Firefox current supports the ``WM_GESTURE`` message when Asynchronous Pan
+    and Zoom (APZ) is not enabled (although we do not handle inertia in this
+    case, so the page comes to a dead-stop immediately when the user stops
+    scrolling).
+
+
+**2009 - Touch Support: WM_TOUCH (Windows 7)**
+
+    Also introduced in Windows 7, an application that needs full control over
+    touchscreen events can use `RegisterTouchWindow <https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-registertouchwindow>`__
+    to change any of its windows to receive ``WM_TOUCH`` messages instead of the
+    more high-level ``WM_GESTURE`` messages. These messages explicitly notify
+    the application about every finger that contacts or breaks contact with the
+    digitizer (as well as each finger's movement over time). This provides
+    absolute control over touch interpretation, but also means that the burden
+    of handling touch behavior falls completely on the application.
+
+    To help ease this burden, Microsoft provides two COM APIs to interpret
+    touch messages, ``IManipulationProcessor`` and ``IInertiaProcessor``.
+
+    ``IManipulationProcessor`` can be considered a superset of the functionality
+    available through normal gestures. The application feeds ``WM_TOUCH`` data
+    into it (along with other state, such as pivot points and timestamps), and
+    it allows for manipulations like: two-finger rotation around a pivot,
+    single-finger rotation around a pivot, simultaneous rotation and translation
+    (for example, 'dragging' a single corner of a square).
+    `These MSDN diagrams <https://learn.microsoft.com/en-us/windows/win32/wintouch/advanced-manipulations-overview>`__
+    give a good overview of the kinds of advanced manipulations an app might
+    support.
+
+    ``IInertiaProcessor`` works with ``IManipulationProcessor`` to add inertia
+    to objects in a standard way across the operating system. It is likely that
+    later APIs that provide this (like DirectManipulation) are using these COM
+    objects under the hood to accomplish their inertia handling.
+
+    Firefox currently handles the ``WM_TOUCH`` event when Asynchronous Pan and
+    Zoom (APZ) is enabled, but we do not use either the ``IInertiaProcessor``
+    nor the ``IManipulationProcessor``.
+
+
+**2012 - Unified Pointer API (Windows 8)**
+
+    Windows 8 (2012) was Microsoft's initial attempt to make a touch-first,
+    mobile-first operating system that (ideally) would make it easy for app
+    developers to treat touch, pen, and mouse as first-class input devices.
+
+    By this point, the Windows Tablet APIs would allow tablet pens to draw
+    text and shapes like squares, triangles, and music notes, and those shapes
+    would be recognizable by the Windows Ink subsystem.
+
+    At the same time, Windows Touch allowed touchscreens to have advanced
+    manipulation, like rotate + translate, or simultaneous pan and zoom, and it
+    allowed objects manipulated by touch to have momentum and angular velocity.
+
+    The shortcomings of having separate input stacks for these various devices
+    starts to be become apparent after a while: Why shouldn't a touchscreen be
+    able to recognize a circle or a triangle? Why shouldn't a pen be able to
+    have complex rotation and zoom functionality? How do we handle these newer
+    laptop touchpads that are starting to handle multi-touch gestures like a
+    touchscreen, but still cause relative cursor movement like a mouse? Why does
+    my program have to have 3 separate codepaths for different pointing devices
+    that are all very similar?
+
+    The Windows Pointer Device Input Stack introduces new APIs and window
+    messages that generalize the various types of pointing devices under a
+    single API while still falling back to the legacy touch and tablet input
+    stacks in the event that the API is unused. (Note that the touch and tablet
+    stacks themselves fall back to the traditional mouse input stack when they
+    are unused.)
+
+    Microsoft based their pointer APIs off the Buxton Three-State Model
+    (discussed earlier), where changes between "Out-of-Range" and "Tracking" are
+    signalled by ``WM_POINTERENTER`` AND ``WM_POINTERLEAVE`` messages, and
+    changes between "Tracking" and "Dragging" are signalled by
+    ``WM_POINTERDOWN`` and ``WM_POINTERUP``. Movement is indicated via
+    ``WM_POINTERUPDATE`` messages.
+
+    If these messages are unhandled (the message is forwarded to
+    ``DefWindowProc``), the Win32 subsystem will translate them
+    into touch or gesture messages. If unhandled, those will be further
+    translated into mouse and system messages.
+
+    While the Pointer API is not without some unfortunate pitfalls (which will
+    be discussed later), it still provides several advantages over the
+    previously available APIs: it can allow a mostly-unified codepath for
+    handling pointing devices, it circumvents many of the often-complex
+    interactions between the previous APIs, and it provides the ability to
+    simulate pointing devices to help facilitate end-to-end automated testing.
+
+    Firefox currently uses the Pointer APIs to handle tablet stylus input only,
+    while other input methods still use the historical mouse and touch input
+    APIs above.
+
+
+**2013 - DirectManipulation (Windows 8.1)**
+
+    DirectManipulation is a DirectX based API that was added during the release
+    of Windows 8.1 (2013). This API allows an app to create a series of
+    "viewports" inside a window and have scrollable content within each of these
+    viewports. The manipulation engine will then take care of automatically
+    reading Pointer API messages from the window's event queue and generating
+    pan and zoom events to be consumed by the app.
+
+    In the case that the app is also using DirectComposition to draw its window,
+    DirectManipulation can pipe the events directly into it, causing the app
+    to essentially get asynchronous pan and zoom with proper handling of inertia
+    and overscroll with very little coding.
+
+    DirectManipulation is only used in Firefox to handle data coming from
+    Precision Touchpads, as Microsoft provides no other convenient API for
+    obtaining data from such devices. Firefox creates fake content inside of
+    a fake viewport to capture the incoming events from the touchpad and
+    translates them into the standard Asynchronous Pan and Zoom (APZ) events
+    that the rest of the input pipeline uses.
+
+
+**2013 - Touch Events (Web Standard)**
+
+    "`Touch Events <https://www.w3.org/TR/touch-events/>`__" became a W3C
+    recommendation in October, 2013.
+
+    At this point, Microsoft's first operating system to include touch support
+    (Windows 7) was the most popular desktop operating system, and the ubiquity
+    of smart phones brought a huge uptick in users with touchscreen inputs. All
+    major browsers included some API that allowed reading touch input,
+    prompting the W3C to formalize a new standard to ensure interoperability.
+
+    With the Touch Events API, multiple touch interactions may be reported
+    simultaneously, each with their own separate identifier for tracking and
+    their own coordinates within the screen, viewport, and client area. A
+    touch is reported by: a ``touchstart`` event with a unique ID for each
+    contact, zero-or-more ``touchmove`` events with that ID, and finally a
+    ``touchend`` event to signal the end of that specific contact.
+
+    The API also has some amount of support for pen styluses, but it lacks
+    important features necessary to truly support them: hovering, pressure,
+    tilt, or multiple cursors like an erasure. Ultimately, its functionality
+    has been superceded by the newer "Pointer Events" API, discussed below.
+
+
+**2016 - Precision Touchpads (Windows 10)**
+
+    Early touchpads emulated a computer mouse by directly using the same IBM
+    PS/2 interface that most computer mice used and translating relative
+    movement of the user's finger into equivalent movements of a mouse on a
+    surface.
+
+    As touchpad technology advanced and more powerful interface standards like
+    USB begun to take over the consumer market, touchpad vendors started adding
+    extra features to their hardware, like tap-to-click, tap-and-drag, and
+    tap-and-hold (to simulate a right click). These behaviors were implemented
+    by touchpad vendors either in hardware drivers and/or user mode "hooks" that
+    injected equivalent Win32 messages into the appropriate target.
+
+    As expected, each touchpad vendor's driver had its own subtly-different
+    behavior from others, its own bugs, and its own negative interactions with
+    other software.
+
+    During the later years of Windows 8, Microsoft and touchpad company
+    Synaptics co-developed the "Precision Touchpad" standard, which defines an
+    interface for touchpad hardware to report its physical measurements,
+    precision, and sensor configuration to Windows and allows it to deliver raw
+    touch data. Windows then interprets the data and generates gestures and
+    window messages in a standard way, removing the burden of implementing these
+    behaviors from the touchpad vendor and providing the OS with rich
+    information about the user's movements.
+
+    It wasn't until the 2016 release of Windows 10 14946 that Microsoft would
+    support all the standard gestures through the new standard. Although
+    adoption by vendors has been a bit slow, the fact that
+    `it is a requirement for Windows 11 <https://pocketnow.com/all-windows-11-pcs-will-be-required-to-have-a-precision-touchpad-and-webcam/>`__
+    means that vendor support for this standard is imminent.
+
+    Unfortunately, there's a piece of bad news: Microsoft did not
+    implement the above "Unified Pointer API" for use with touchpads, as the
+    developers of Blender discovered when `they moved to the Pointer API <https://archive.blender.org/developer/D7660>`__.
+    Instead, Microsoft expects developers to either use DirectManipulation to
+    automatically get pan/zoom enabled for their app, or the RawInput API to
+    directly read touchpad data.
+
+
+**2019 - Pointer Events (Web Standard)**
+
+    "`Pointer Events <https://www.w3.org/TR/pointerevents/>`__" became a level 2
+    W3C recommendation in April, 2019. They considered `the work done by Microsoft <https://www.w3.org/Submission/2012/SUBM-pointer-events-20120907/>`__
+    as part of the design of their own Pointer API, and in many ways the W3C
+    standard resembles an improved, better specified, more consistent, and
+    easier-to-use version of the APIs provided by the Win32 subsystem.
+
+    The Pointer Events API generalizes devices like touchscreens, mice, tablet
+    pens, VR controllers, etc. into a "thing that points". A pointer has
+    (optional) properties: a width and height (big for a finger, 1px for a
+    mouse), an amount of pressure, a tilt angle relative to the surface, some
+    buttons, etc. This helps applications maximize code reuse for handling
+    pointer input by having a common codebase written against these generalized
+    traits. If needed, the application may also have smaller, specialized
+    sections of code for each concrete pointer type.
+
+    Certain types of pointers (like pens and touchscreens) have a behavior where
+    they are always "captured" by the first object that they interact with. For
+    example, if a user puts their finger on an empty part of a web page and
+    starts to scroll, their finger is now "captured" by the web page itself.
+    "Captured" means that even if their finger moves over an element in
+    the web page, that element will not receive events from the finger -- the
+    page itself will until the entire interaction stops.
+
+    The events themselves very closely follow the Buxton Three-State Model
+    (discussed earlier), where  ``pointerover/pointerout`` messages indicate
+    transitions from "Out of Range" to "Tracking" and visa-versa, and
+    ``pointerdown/pointerup`` messages transition between "Tracking" and
+    "Dragging". ``pointermove`` updates the position of the pointer, and a
+    special ``pointercancel`` message is sent to inform the page that the
+    browser is "cancelling" a ``pointerdown`` event because it has decided to
+    consume it for a gesture or because the operating system cancelled the
+    pointer for its own reasons.
+
+
+CSS "interaction" Media Queries
+==========================================
+
+(Note that this section is **not** about the `pointer-events <https://developer.mozilla.org/en-US/docs/Web/CSS/pointer-events>`__
+CSS property, which defines the circumstances where an element can be the target
+of pointer events.)
+
+The W3C defines the interaction-related media queries in the
+`Media Queries Level 4 - Interaction Media Features <https://www.w3.org/TR/mediaqueries-4/#mf-interaction>`__
+document.
+
+To summarize, the main interaction-related CSS Media Queries that Firefox must
+support are ``pointer``,  ``any-pointer``, ``hover`` and ``any-hover``.
+
+
+``pointer``
+
+    Allows the webpage to query the existence of a pointing device on
+    the machine, and (if available) the assumed "pointing accuracy" of the
+    "primary" pointing device. The device considered "primary" on a machine with
+    multiple input devices is a policy decision that must be made by the web
+    browser; Windows simply provides the APIs to query information about
+    attached devices.
+
+    The browser is expected to return one of three strings to this media query:
+
+    ``none``
+
+        There is no pointing device attached to the computer.
+
+    ``coarse``
+
+        The primary pointing device is capable of approximately
+        pointing at a relatively large target (like a finger on a
+        touchscreen).
+
+    ``fine``
+
+        The primary pointing device is capable of near-pixel-level
+        accuracy (like a computer mouse or a tablet pen).
+
+
+``any-pointer``
+
+    Similar to ``pointer``, but represents the union of
+    capabilities of all pointers attached to the system, such that the meanings
+    become:
+
+    ``none``
+
+        There is no pointing device attached to the computer.
+
+    ``coarse``
+
+        There is at-least one "coarse" pointer attached.
+
+    ``fine``
+
+        There is at-least one "fine" pointer attached.
+
+
+``hover``
+
+    Allows the webpage to query whether the primary pointer is
+    capable of "hovering" over top of elements on the page. Computer mice,
+    touchpad cursors, and higher-end pen tablets all support this, whereas
+    current touchscreens are "touch" or "no touch", and they cannot detect a
+    finger hovering over the screen.
+
+    ``hover``
+
+        The primary pointer is capable of reporting hovering.
+
+    ``none``
+
+        The primary pointer is not capable of reporting hovering.
+
+``any-hover``
+
+    Indicates whether any pointer attached to the system has the
+    ``hover`` capability.
+
+
+Selection of the Primary Pointing Device
+--------------------------------------------
+
+To illustrate the complexity of this topic, consider the Microsoft Surface Pro.
+
+The Surface Pro has an advanced screen that is capable of receiving touch
+input, but it can also behave like a pen digitizer and receive input from a
+stylus with advanced pen capabilities, like hover sensing, pressure
+sensitivity, multiple buttons, and even multiple "tips" (a pen and eraser end).
+
+In this case, what should Firefox consider the primary pointing device?
+
+Perhaps the user intends to use their Surface Pro like a touchscreen tablet,
+at which point Firefox should report ``pointer: coarse`` and ``hover: none``
+capabilities.
+
+But what if, instead, the user wants to sketch art or take notes using a pen on
+their Surface Pro? In this case, Firefox should be reporting ``pointer: fine``
+and ``hover: hover``.
+
+Imagine that the user then attaches the "keyboard + touchpad" cover attachment
+to their Surface Pro; naturally, we will consider that the user's intent is for
+the touchpad to become the primary pointing device, and so it is fairly clear
+that we should return ``pointer: fine`` and ``hover: hover`` in this state.
+
+However, what if the user tucks the keyboard/touchpad attachment behind the
+tablet and begins exclusively operating the device with their finger?
+
+This example shows that complex, multi-input machines can resist classification
+and blur the lines between labels like "touch device", "laptop", "drawing
+tablet", etc. It also illustrates that identifying the "primary" pointing
+device using only machine configuration may yield unintuitive and suboptimal
+results.
+
+While we can almost-certainly improve our hardware detection heuristics to
+better answer this question (and we should, at the very least), perhaps it
+makes more sense for Firefox to incorporate user intentions into the decision.
+Intentions could be communicated directly by the user through some sort of
+setting or indirectly through the user's actions.
+
+For example, if the user intends to draw on the screen with a pen, perhaps
+Firefox provides something like a "drawing mode" that the user can toggle to
+change the primary pointing device to the pen. Or perhaps it's better for
+Firefox to interpret the mere fact of receiving pen input as evidence of the
+user's intent and switch the reported primary pointing device automatically.
+
+If we wanted to switch automatically, there are predictable traps and pitfalls
+we need to think about: we need to ensure that we don't create frustrating user
+experiences where web pages may "pop" beneath the user suddenly, and
+we should likely incorporate some kind of "settling time" so we don't
+oscillate between devices.
+
+It's worth noting that Chromium doesn't seem to incorporate anything like
+what's being suggested here, so if this is well-designed it may be an
+opportunity for Firefox to try something novel.
+
+
+
+
+================================================================================
+State of the Browser
+================================================================================
+
+Pan and Zoom, Inertia, Overscroll, and Elastic Bounce
+=========================================================
+
+As can be seen in the videos below, Firefox's support for inertia, overscroll,
+and elastic bounce works well on all platforms when a stylus pen is used
+as the input device, and it also works just fine with the touchscreen on the
+Dell XPS 15. However, it completely fails when the touchscreen is used on
+the Microsoft Surface Pro. While more investigation is needed to completely
+understand these issues, the fact that the correctly-behaving digitizing pens
+use the Pointer API and the misbehaving input devices do not may be related.
+
+-   `Video 1 <https://drive.google.com/file/d/1Z1QRSf2RluNhJwkKCzPb6-14vRtkqK8s/view?usp=sharing>`__
+    showcasing overscroll and bounce not working on Surface Pro with touch, but
+    other devices/inputs are working
+
+-   `Video 2 <https://drive.google.com/file/d/1bOgpVGBeZtwelvPJzYdA6uFRpubGtu4W/view?usp=sharing>`__
+    showing that everything works just fine with an external Wacom digitizer
+
+
+Pointer Media Queries
+=========================================================
+
+**"any-pointer" Queries**
+
+Unlike the ``pointer`` media queries, which rely on the browser to make a policy
+decision about what should be considered the "primary" pointer in a given
+system configuration, the ``any-pointer`` queries are much more objective and
+binary: the computer either has a type of device attached to it, or it
+doesn't.
+
+**any-pointer: coarse**
+
+Firefox reports that there are "coarse" pointing devices present if either of
+these two points is true:
+
+1.  ``GetSystemMetrics(SM_DIGITIZER)`` reports that a device that supports
+    touch or pen is present.
+
+2.  Based on heuristics, Firefox concludes that it is running on a computer it
+    considers a "tablet".
+
+Point #1 is incorrect, as a pen is not a "coarse" pointing device. Note that
+this is a recent regression in `Bug 1811303 <https://bugzilla.mozilla.org/show_bug.cgi?id=1811303>`__
+that was uplifted to Firefox 112, so this actually regressed as this document
+was being written! This is responsible for the incorrect "Windows 10 Desktop +
+Wacom USB Tablet" issue in the table.
+
+Point #2 is a clear case of the `XY Problem <https://en.wikipedia.org/wiki/XY_problem>`__,
+where Firefox is trying to determine if a coarse pointing device is present
+by determining whether it is running on a tablet, when instead it should be
+directly testing for coarse pointing devices (since, of course, those can exist
+on machines that wouldn't normally be considered a "tablet"). This is
+responsible for the incorrect "Windows 10 Dell XPS 15 (Touch Disabled) + Wacom
+USB Tablet" issue in the table below.
+
+**any-pointer: fine**
+
+Firefox reports that there are "fine" pointing devices present if and only if
+it detects a mouse. This is clearly already wrong. Firefox determines that the
+computer has a mouse using the following algorithm:
+
+1.  If ``GetSystemMetrics(SM_MOUSEPRESENT)`` returns false, report no mouse.
+
+2.  If Firefox does not consider the current computer to be a tablet, report a
+    mouse if there is at-least one "mouse" device driver running on the
+    computer.
+
+3.  If Firefox considers the current computer to be a tablet or a touch system,
+    only report a mouse if there are at-least two "mouse" device drivers
+    running. This exists because some tablet pens and touch digitizers report
+    themselves as computer mice.
+
+This algorithm also suffers from the XY problem -- Firefox is trying to
+determine whether a fine pointing device exists by determining if there is
+a computer mouse present, when instead it should be directly testing for
+fine pointing devices, since mice are not the only fine pointing
+devices.
+
+Because of this proxy question, this algorithm is completely dependent on any
+attached fine pointing device (like a pen tablet) to report itself as a mouse.
+Point #3 makes the problem even worse, because if a computer that resembles a
+tablet fails to report its digitizers as mice, the algorithm will completely
+ignore an actual computer mouse attached to the system because it expects two
+of them to be reported!
+
+Unfortunately, the Surface Pro has both a pen digitizer and a touch digitizer,
+and it reports neither as a mouse. As a result, this algorithm completely falls
+apart on the Surface Pro, failing to report any "fine" pointing device even
+when a computer mouse is plugged in, a pen is plugged in, or even when
+the tablet is docked because its touchpad is only one mouse and it expects
+at least two.
+
+This is also responsible for failing to report the trackpad on the Dell XPS 15
+as "fine", because the Dell XPS 15 has a touchscreen and therefore looks like
+a "tablet", but doesn't report 2 mouse drivers.
+
+**any-pointer: hover**
+
+
+Firefox reports that any device that is a "fine" pointer also supports "hover",
+which does generally hold true, but isn't necessarily true for lower-end pens
+that only support tapping. It would be better for Firefox to directly
+query the operating system instead of just assuming.
+
+**"pointer" media query**
+
+As discussed previously at length, this media query relies on a "primary"
+designation made by the browser. Below is the current algorithm used to
+determine this:
+
+1.  If the computer is considered a "tablet" (see below), report primary
+    pointer as "coarse" (this is clearly already the wrong behavior).
+
+2.  Otherwise, if the computer has a mouse plugged in, report "fine".
+
+3.  Otherwise, if the computer has a touchscreen or pen digitizer, report
+    "coarse" (this is wrong in the case of the digitizer).
+
+4.  Otherwise, report "fine" (this is wrong; should report "None").
+
+Firefox uses the following algorithm to determine if the computer is a
+"tablet" for point #1 above:
+
+1.  It is not a tablet if it's not at-least running Windows 8.
+
+2.  If Windows "Tablet Mode" is enabled, it is a tablet no matter what.
+
+3.  If no touch-capable digitizers are attached, it is not a tablet.
+
+4.  If the system doesn't support auto-rotation, perhaps because it has
+    no rotation sensor, or perhaps because it's docked and operating in
+    "laptop mode" where rotation won't happen, it's not a tablet.
+
+5.  If the vendor that made the computer reports to Windows that it supports
+    "convertible slate mode" and it is currently operating in "slate mode",
+    it's a tablet.
+
+6.  Otherwise, it's not a tablet.
+
+
+**Table with comparison to Chromium**
+
+The following table shows how Firefox and Chromium respond to various pointer
+queries. The "any-pointer" and "any-hover" columns are not subjective and
+therefore are always either green or red to indicate "pass" or "fail", but the
+"pointer" and "hover" may also be yellow to indicate that it's "open to
+interpretation" because of the aforementioned difficulty in determining the
+"primary pointer".
+
+.. image:: touch_media_queries.png
+    :width: 100%
+
+
+**Related Bugs**
+
+-   Bug 1813979 - For Surface Pro media query "any-pointer: fine" is true only
+    when both the Type Cover and mouse are connected
+
+-   Bug 1747942 - Incorrect CSS media query matches for pointer, any-pointer,
+    hover and any-hover on Surface Laptop
+
+-   Bug 1528441 - @media (hover) and (any-hover) does not work on Firefox 64/65
+    where certain dual inputs are present
+
+-   Bug 1697294 - Content processes unable to detect Windows 10 Tablet Mode
+
+-   Bug 1806259 - CSS media queries wrongly detect a Win10 desktop computer
+    with a mouse and a touchscreen, as a device with no mouse (hover: none)
+    and a touchscreen (pointer: coarse)
+
+
+Web Events
+=====================
+
+The pen stylus worked well on all tested systems -- The correct pointer events
+were fired in the correct order, and mouse events were properly simulated in
+case the default behavior was allowed.
+
+The touchscreen input was less reliable. On the Dell XPS 15, the
+"Pointer Events" were flawless, but the "Touch Events" were missing
+an important step: the ``touchstart`` and ``touchmove`` messages were sent just
+fine, but Firefox never sends the ``touchend`` message! (Hopefully that isn't
+too difficult to fix!)
+
+Unfortunately, everything really falls apart on the Surface Pro using the
+touchscreen -- neither the "Pointer Events" nor the "Touch Events" fire at all!
+Instead, the touch is completely absorbed by pan and zoom gestures, and nothing
+is sent to the web page. The website's request for ``touch-action: none`` is
+ignored, and the web page is never given any opportunity to call
+``Event.preventDefault()`` to cancel the pan/zoom behavior.
+
+
+Operating System Interfaces
+================================
+
+As was discussed above, Windows has multiple input APIs that were each
+introduced in newer version of Windows to handle devices that were not
+well-served by existing APIs.
+
+Backward compatibility with applications designed against older APIs is
+realized when applications call the default event handler (``DefWindowProc``)
+upon receiving an event type that they don't recognize (which is what apps have
+always been instructed to do if they receive events they don't recognize).
+The unrecognized newer events will be translated by the default event handler
+into older events and sent back to the application. A very old application may
+have this process repeat through several generations of APIs until it finally
+sees events that it recognizes.
+
+Firefox currently uses a mix of the older and newer APIs, which complicates
+the input handling logic and may be responsible for some of the
+difficult-to-explain bugs that we see reported by users.
+
+Here is an explanation of the codepaths Firefox uses to handle pointer input:
+
+1.  Firefox handles the ``WM_POINTER[LEAVE|DOWN|UP|UPDATE]`` messages if the
+    input device is a tablet pen and an Asynchronous Pan and Zoom (APZ)
+    compositor is available. Note that this already may not be ideal, as
+    Microsoft warns (`here <https://learn.microsoft.com/en-us/windows/win32/inputmsg/wm-pointercapturechanged>`__)
+    that handling some pointer messages and passing other pointer messages to
+    ``DefWindowProc`` has unspecified behavior (meaning that Win32 may do
+    something unexpected or nonsensical).
+
+    If the above criteria aren't met, Firefox will call ``DefWindowProc``, which
+    will re-post the pointer messages as either touch messages or mouse
+    messages.
+
+2.  If DirectManipulation is being used for APZ, it will output the
+    ``WM_POINTERCAPTURECHANGED`` if it detects a pan or zoom gesture it can
+    handle. It will then handle the rest of the gesture itself.
+
+    DirectManipulation is used for all top-level and popup windows as long as
+    it isn't disabled via the ``apz.allow_zooming``,
+    ``apz.windows.use_direct_manipulation``, or
+    ``apz.windows.force_disable_direct_manipulation`` prefs.
+
+3.  If the pointing device is touch, the next action depends on
+    whether an Asynchronous Pan and Zoom (APZ) compositor is available. If it
+    is, the window will have been registered using ``RegisterTouchWindow``, and
+    Firefox will receive ``WM_TOUCH`` messages, which will be sent to the
+    "Touch Event" API and handled directly by the APZ compositor.
+
+    If there is no APZ compositor, it will instead be received as a
+    ``WM_GESTURE`` message or a mouse message, depending on the movement. Note
+    that these will be more basic gestures, like tap-and-hold.
+
+4.  If none of the above apply, the message will be converted into standard
+    ``WM_MOUSExxx`` messages via a call to ``DefWindowProc``.
+
+
+================================================================================
+Discussion
+================================================================================
+
+Here is where some of the outstanding thoughts or questions can be listed.
+This can be updated as more questions come about and (hopefully) as answers to
+questions become apparent.
+
+CSS "pointer" Media Queries
+===============================
+
+-   The logic for the ``any-pointer`` and ``any-hover`` queries are objectively
+    incorrect and should be rewritten altogether. That is not as
+    big of a job as it sounds, as the code is fairly straightforward and
+    self-contained. (Note: Improvements have already been made in
+    `Bug 1813979 <https://bugzilla.mozilla.org/show_bug.cgi?id=1813979>`__)
+
+-   There are a few behaviors for ``pointer`` and ``hover`` that are
+    objectively wrong (such as reporting a ``coarse`` pointer when the
+    Surface Pro is docked with a touchpad). Those should be fixable with a
+    code change similar to the previous bullet.
+
+-   Do we want to continue to use only machine configuration to decide what
+    the "primary" pointer is, or do we also want to incorporate user intent
+    into the algorithm? Or, alternatively:
+
+    1.  Do we create a way for the user to override? For example, a "Drawing
+        Mode" button if a tablet digitizer is sensed.
+
+    2.  Do we attempt to change automatically in response to user action?
+
+        -   An example was used above of a docked Surface Pro computer, where
+            the user may use the keyboard and touchpad for a while, then perhaps
+            tuck that behind and use the device as a touchscreen, and then
+            perhaps draw on it with a tablet stylus.
+
+        -   We would need to be careful to avoid careless "popping" or
+            "oscillating" if we react too quickly to changing input types.
+
+-   On a separate-but-related note, the `W3C suggested <https://www.w3.org/TR/mediaqueries-5/#descdef-media-pointer>`__
+    that it might be beneficial to allow users to at-least disable all
+    reporting of ``fine`` pointing devices for users who may have a disability
+    that prevents them from being able to click small objects, even with a fine
+    pointing device.
+
+
+Pan-and-Zoom, Inertia, Overscroll, and Elastic Bounce
+=========================================================
+
+-   Inertia, overscroll, and elastic bounce are just plain broken on the
+    Surface Pro. That should definitely be investigated.
+
+-   We can see from the video below that Microsoft Edge has quite a bit more
+    overscroll and a more elastic bounce than Firefox does, and it also
+    allows elastic bounce in directions that the page itself doesn't scroll.
+
+    Edge's way seems more similar to the user experience I'd expect from using
+    Firefox on an iPhone or Android device. Perhaps we should consider
+    following suit?
+
+    (`Link to video <https://drive.google.com/file/d/14XVLT6CNn2RaXcHHCRIrQmRwoMYjj6fu/view?usp=sharing>`__)
+
+
+Web Events
+==============
+
+-   It's worth investigating why the ``touchend`` message never seems
+    to be sent by Firefox on any tested devices.
+
+-   It's very disappointing that neither the Pointer Events API nor the
+    Touch Events API works at all on Firefox on the Surface Pro. That should
+    be investigated very soon!
+
+
+Operating System Interfaces
+================================
+
+-   With the upcoming sun-setting of Windows 7 support, Firefox has an
+    opportunity to revisit the implementation of our input handling and try to
+    simplify our codepaths and eliminate some of the workarounds that exist to
+    handle some of these complex interactions, as well as fix entire classes of
+    bugs - both reported and unreported - that currently exist as a result.
+
+-   Does it make sense to combine the touchscreen and pen handling together
+    and use the ``WM_POINTERXXX`` messages for both?
+
+    -   This would eliminate the need to handle the ``WM_TOUCH`` and
+        ``WM_GESTURE`` messages at all.
+
+    -   Note that there is precedent for this, as  `GTK <https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/1563>`__
+        has already done so. It appears that `Blender <https://archive.blender.org/developer/D7660>`__
+        has plans to move toward this as well.
+
+    -   Tablet pens seemed to do very well in most of the testing,
+        and they are also the part of the code that mainly exercises the
+        ``WM_POINTERXXX`` codepaths. That may imply increased reliability in
+        that codepath?
+
+    -   The Pointer APIs also have good device simulation for integration
+        testing.
+
+    -   Would we also want to roll mouse handling into it using the
+        `EnableMouseInPointer <https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-enablemouseinpointer>` __
+        call? That would allow us to also get rid of handling
+        ``WM_MOUSE[MOVE/WHEEL/HWHEEL]`` and ``WM_[LRM]BUTTON[UP|DOWN]``
+        messages. Truly one codepath (with a few minor branches) to rule them
+        all!
+
+    -   Nick Rishel sent `this link <http://the-witness.net/news/2012/10/wm_touch-is-totally-bananas/>`__
+        that details the troubles that the developers of The Witness (a video
+        game) ran into when using the ``WM_TOUCH`` API. It argues that the API
+        is poorly-designed, and advises that if Windows 7 support is not
+        needed, the API should be avoided.
+
+-   Should we exclusively use DirectManipulation for Pan/Zoom?
+
+    -   Multitouch touchpads bypass all of the ``WM_POINTER`` machinery
+        for anything gesture-related and directly send their messages to
+        DirectManipulation. We then "capture" all the DirectManipulation events
+        and pump them into our events pipeline, as explained above.
+
+    -   DirectManipulation also handles "overscroll + elastic bounce" in a way
+        that aligns with Windows look-and-feel.
+
+    -   Perhaps it makes sense to just use DirectManipulation for all APZ
+        handling and eliminate any attempt at handling this through other
+        codepaths.
+
+High-Frequency Input
+================================
+
+"High-Frequency Input" refers to the ability for an app to be able to still
+perceive input events despite them happening at a rate faster than the app
+itself actually handles them.
+
+Consider a mouse that moves through several points: "A->B->C->D->E". If the
+application processes input when the mouse is at "A" and doesn't poll again
+until the mouse is at point "E", the default behavior of all modern operating
+systems is to "coalesce" these events and simply report "A->E". This is fine
+for the majority of use cases, but certain workloads (such as digital
+handwriting and video games) can benefit from knowing the complete path that
+was taken to get from the start point to the end point.
+
+Generally, solutions to this involve the operating system keeping a history of
+pointer movements that can be retrieved through an API. For example,
+Android provides the `MotionEvent <https://developer.android.com/reference/android/view/MotionEvent.html>`__
+API that batches historal movements.
+
+Unfortunately, the APIs to do this in Windows are terribly broken. As
+`this blog <https://blog.getpaint.net/2019/11/14/paint-net-4-2-6-alpha-build-7258/>`__
+makes clear, `GetMouseMovePointsEx <https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getmousemovepointsex>`__
+has so many issues that they had to remove its usage from their program because
+of the burden. That same blog entry also details that the newer Pointer API has
+the `GetPointerInfoHistory <https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getpointerinfohistory>`__
+that is *supposed* to support tracking pointer history, but it only ever tracks
+a single entry!
+
+Perhaps luckily, there is currently no web standard for high-frequency input,
+although it `has been asked about in the past <https://lists.w3.org/Archives/Public/public-pointer-events/2014AprJun/0057.html>`__.
+
+If such a standard was ever created, it would likely be very difficult for
+Firefox on Windows to support it.
+
+
+DirectManipulation and Pens
+=============================
+
+-   This is a todo item, but it needs to be investigated whether or not
+    DirectManipulation can directly scoop up pen input, or whether it has
+    to be handled by the application (and forwarded to DM if desired).
diff --git a/widget/windows/docs/windows-pointing-device/mouse.jpg b/widget/windows/docs/windows-pointing-device/mouse.jpg
new file mode 100644
index 0000000000..c4fca9ba31
--- /dev/null
+++ b/widget/windows/docs/windows-pointing-device/mouse.jpg
diff --git a/widget/windows/docs/windows-pointing-device/touch_media_queries.png b/widget/windows/docs/windows-pointing-device/touch_media_queries.png
new file mode 100644
index 0000000000..f0de661d7f
--- /dev/null
+++ b/widget/windows/docs/windows-pointing-device/touch_media_queries.png
diff --git a/widget/windows/docs/windows-pointing-device/touchpad.jpg b/widget/windows/docs/windows-pointing-device/touchpad.jpg
new file mode 100644
index 0000000000..1327ec5b1c
--- /dev/null
+++ b/widget/windows/docs/windows-pointing-device/touchpad.jpg
diff --git a/widget/windows/docs/windows-pointing-device/touchscreen.jpg b/widget/windows/docs/windows-pointing-device/touchscreen.jpg
new file mode 100644
index 0000000000..90246ca02e
--- /dev/null
+++ b/widget/windows/docs/windows-pointing-device/touchscreen.jpg
diff --git a/widget/windows/docs/windows-pointing-device/trackpoint.jpg b/widget/windows/docs/windows-pointing-device/trackpoint.jpg
new file mode 100644
index 0000000000..9eae5b5c21
--- /dev/null
+++ b/widget/windows/docs/windows-pointing-device/trackpoint.jpg
diff --git a/widget/windows/docs/windows-pointing-device/vrcontroller.jpg b/widget/windows/docs/windows-pointing-device/vrcontroller.jpg
new file mode 100644
index 0000000000..20f2e90bfe
--- /dev/null
+++ b/widget/windows/docs/windows-pointing-device/vrcontroller.jpg
diff --git a/widget/windows/docs/windows-pointing-device/wacom_tablet.png b/widget/windows/docs/windows-pointing-device/wacom_tablet.png
new file mode 100644
index 0000000000..2bc30a3b4f
--- /dev/null
+++ b/widget/windows/docs/windows-pointing-device/wacom_tablet.png
diff --git a/widget/windows/filedialog/PWinFileDialog.ipdl b/widget/windows/filedialog/PWinFileDialog.ipdl
new file mode 100644
index 0000000000..812db7e103
--- /dev/null
+++ b/widget/windows/filedialog/PWinFileDialog.ipdl
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=ipdl : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include WinFileDialogCommandsDefn;
+using mozilla::WindowsHandle from "mozilla/ipc/IPCTypes.h";
+using mozilla::widget::filedialog::FileDialogType from "mozilla/widget/filedialog/WinFileDialogCommands.h";
+
+namespace mozilla {
+namespace widget {
+namespace filedialog {
+
+[ChildProc=Utility]
+protocol PWinFileDialog {
+
+child:
+  // Exactly one Show function should be called per instance. Further calls will
+  // result in IPC failure.
+  //
+  // Each will return `Nothing` iff the operation was canceled by the user.
+
+  async ShowFileDialog(WindowsHandle parentHwnd, FileDialogType type, Command[] commands)
+    returns (Results? results);
+  async ShowFolderDialog(WindowsHandle parentHwnd, Command[] commands)
+    returns (nsString? path);
+};
+
+}  // namespace filedialog
+}  // namespace widget
+}  // namespace mozilla
diff --git a/widget/windows/filedialog/WinFileDialogChild.cpp b/widget/windows/filedialog/WinFileDialogChild.cpp
new file mode 100644
index 0000000000..1a2903f8ec
--- /dev/null
+++ b/widget/windows/filedialog/WinFileDialogChild.cpp
@@ -0,0 +1,110 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/widget/filedialog/WinFileDialogChild.h"
+
+#include <combaseapi.h>
+#include <objbase.h>
+#include <shobjidl.h>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/ipc/ProtocolUtils.h"
+#include "mozilla/widget/filedialog/WinFileDialogCommands.h"
+#include "nsPrintfCString.h"
+
+namespace mozilla::widget::filedialog {
+
+/* extern */ mozilla::LazyLogModule sLogFileDialog("FileDialog");
+
+WinFileDialogChild::WinFileDialogChild() {
+  MOZ_LOG(sLogFileDialog, LogLevel::Info, ("%s %p", __PRETTY_FUNCTION__, this));
+};
+
+WinFileDialogChild::~WinFileDialogChild() {
+  MOZ_LOG(sLogFileDialog, LogLevel::Info, ("%s %p", __PRETTY_FUNCTION__, this));
+};
+
+#define MOZ_ABORT_IF_ALREADY_USED()                                            \
+  do {                                                                         \
+    MOZ_RELEASE_ASSERT(                                                        \
+        !mUsed, "called Show* twice on a single WinFileDialog instance");      \
+    MOZ_LOG(                                                                   \
+        sLogFileDialog, LogLevel::Info,                                        \
+        ("%s %p: first call to a Show* function", __PRETTY_FUNCTION__, this)); \
+    mUsed = true;                                                              \
+  } while (0)
+
+template <size_t N>
+WinFileDialogChild::IPCResult WinFileDialogChild::MakeIpcFailure(
+    HRESULT hr, const char (&what)[N]) {
+  // The crash-report annotator stringifies integer values anyway. We do so
+  // eagerly here to avoid questions about C int/long conversion semantics.
+  nsPrintfCString data("%lu", hr);
+  CrashReporter::AnnotateCrashReport(
+      CrashReporter::Annotation::WindowsFileDialogErrorCode, data);
+
+  return IPC_FAIL(this, what);
+}
+
+#define MOZ_IPC_ENSURE_HRESULT_OK(hr, what)             \
+  do {                                                  \
+    MOZ_LOG(sLogFileDialog, LogLevel::Verbose,          \
+            ("checking HRESULT for %s", what));         \
+    HRESULT const _hr_ = (hr);                          \
+    if (FAILED(_hr_)) {                                 \
+      MOZ_LOG(sLogFileDialog, LogLevel::Error,          \
+              ("HRESULT %8lX while %s", (hr), (what))); \
+      return MakeIpcFailure(_hr_, (what));              \
+    }                                                   \
+  } while (0)
+
+WinFileDialogChild::IPCResult WinFileDialogChild::RecvShowFileDialog(
+    uintptr_t parentHwnd, FileDialogType type, nsTArray<Command> commands,
+    FileResolver&& resolver) {
+  MOZ_ABORT_IF_ALREADY_USED();
+
+  SpawnFilePicker(HWND(parentHwnd), type, std::move(commands))
+      ->Then(
+          GetMainThreadSerialEventTarget(), __PRETTY_FUNCTION__,
+          [resolver = std::move(resolver)](Maybe<Results> const& res) {
+            resolver(res);
+          },
+          [self = RefPtr(this)](HRESULT hr) {
+            // this doesn't need to be returned anywhere; it'll crash the
+            // process as a side effect of construction
+            self->MakeIpcFailure(hr, "SpawnFilePicker");
+          });
+
+  return IPC_OK();
+}
+
+WinFileDialogChild::IPCResult WinFileDialogChild::RecvShowFolderDialog(
+    uintptr_t parentHwnd, nsTArray<Command> commands,
+    FolderResolver&& resolver) {
+  MOZ_ABORT_IF_ALREADY_USED();
+
+  SpawnFolderPicker(HWND(parentHwnd), std::move(commands))
+      ->Then(
+          GetMainThreadSerialEventTarget(), __PRETTY_FUNCTION__,
+          [resolver = std::move(resolver)](Maybe<nsString> const& res) {
+            resolver(res);
+          },
+          [self = RefPtr(this), resolver](HRESULT hr) {
+            // this doesn't need to be returned anywhere; it'll crash the
+            // process as a side effect of construction
+            self->MakeIpcFailure(hr, "SpawnFolderPicker");
+          });
+
+  return IPC_OK();
+}
+
+#undef MOZ_IPC_ENSURE_HRESULT_OK
+
+void WinFileDialogChild::ProcessingError(Result aCode, const char* aReason) {
+  detail::LogProcessingError(sLogFileDialog, this, aCode, aReason);
+}
+
+}  // namespace mozilla::widget::filedialog
diff --git a/widget/windows/filedialog/WinFileDialogChild.h b/widget/windows/filedialog/WinFileDialogChild.h
new file mode 100644
index 0000000000..b0939ce2ed
--- /dev/null
+++ b/widget/windows/filedialog/WinFileDialogChild.h
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_filedialog_WinFileDialogChild_h__
+#define widget_windows_filedialog_WinFileDialogChild_h__
+
+#include "mozilla/widget/filedialog/PWinFileDialogChild.h"
+
+// forward declaration of native Windows interface-struct
+struct IFileDialog;
+
+namespace mozilla::widget::filedialog {
+
+class WinFileDialogChild : public PWinFileDialogChild {
+ public:
+  using Command = mozilla::widget::filedialog::Command;
+  using IPCResult = mozilla::ipc::IPCResult;
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WinFileDialogChild, override);
+
+  WinFileDialogChild();
+
+ public:
+  using FileResolver = PWinFileDialogChild::ShowFileDialogResolver;
+  IPCResult RecvShowFileDialog(uintptr_t parentHwnd, FileDialogType,
+                               nsTArray<Command>, FileResolver&&);
+
+  using FolderResolver = PWinFileDialogChild::ShowFolderDialogResolver;
+  IPCResult RecvShowFolderDialog(uintptr_t parentHwnd, nsTArray<Command>,
+                                 FolderResolver&&);
+
+ private:
+  ~WinFileDialogChild();
+
+  void ProcessingError(Result aCode, const char* aReason) override;
+
+  // Defined and used only in WinFileDialogChild.cpp.
+  template <size_t N>
+  IPCResult MakeIpcFailure(HRESULT hr, const char (&what)[N]);
+
+  // This flag properly _should_ be static (_i.e._, per-process) rather than
+  // per-instance; but we can't presently instantiate two separate utility
+  // processes with the same sandbox type, so we have to reuse the existing
+  // utility process if there is one.
+  bool mUsed = false;
+};
+
+}  // namespace mozilla::widget::filedialog
+
+#endif  // widget_windows_filedialog_WinFileDialogChild_h__
diff --git a/widget/windows/filedialog/WinFileDialogCommands.cpp b/widget/windows/filedialog/WinFileDialogCommands.cpp
new file mode 100644
index 0000000000..f0503ab8f0
--- /dev/null
+++ b/widget/windows/filedialog/WinFileDialogCommands.cpp
@@ -0,0 +1,460 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/widget/filedialog/WinFileDialogCommands.h"
+
+#include <type_traits>
+#include <shobjidl.h>
+#include <shtypes.h>
+#include <winerror.h>
+#include "WinUtils.h"
+#include "mozilla/Logging.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "mozilla/WinHeaderOnlyUtils.h"
+#include "mozilla/ipc/ProtocolUtils.h"
+#include "mozilla/ipc/UtilityProcessManager.h"
+#include "mozilla/mscom/ApartmentRegion.h"
+#include "nsThreadUtils.h"
+
+namespace mozilla::widget::filedialog {
+
+// Visitor to apply commands to the dialog.
+struct Applicator {
+  IFileDialog* dialog = nullptr;
+
+  HRESULT Visit(Command const& c) {
+    switch (c.type()) {
+      default:
+      case Command::T__None:
+        return E_INVALIDARG;
+
+      case Command::TSetOptions:
+        return Apply(c.get_SetOptions());
+      case Command::TSetTitle:
+        return Apply(c.get_SetTitle());
+      case Command::TSetOkButtonLabel:
+        return Apply(c.get_SetOkButtonLabel());
+      case Command::TSetFolder:
+        return Apply(c.get_SetFolder());
+      case Command::TSetFileName:
+        return Apply(c.get_SetFileName());
+      case Command::TSetDefaultExtension:
+        return Apply(c.get_SetDefaultExtension());
+      case Command::TSetFileTypes:
+        return Apply(c.get_SetFileTypes());
+      case Command::TSetFileTypeIndex:
+        return Apply(c.get_SetFileTypeIndex());
+    }
+  }
+
+  HRESULT Apply(SetOptions const& c) { return dialog->SetOptions(c.options()); }
+  HRESULT Apply(SetTitle const& c) { return dialog->SetTitle(c.title().get()); }
+  HRESULT Apply(SetOkButtonLabel const& c) {
+    return dialog->SetOkButtonLabel(c.label().get());
+  }
+  HRESULT Apply(SetFolder const& c) {
+    RefPtr<IShellItem> folder;
+    if (SUCCEEDED(SHCreateItemFromParsingName(
+            c.path().get(), nullptr, IID_IShellItem, getter_AddRefs(folder)))) {
+      return dialog->SetFolder(folder);
+    }
+    // graciously accept that the provided path may have been nonsense
+    return S_OK;
+  }
+  HRESULT Apply(SetFileName const& c) {
+    return dialog->SetFileName(c.filename().get());
+  }
+  HRESULT Apply(SetDefaultExtension const& c) {
+    return dialog->SetDefaultExtension(c.extension().get());
+  }
+  HRESULT Apply(SetFileTypes const& c) {
+    std::vector<COMDLG_FILTERSPEC> vec;
+    for (auto const& filter : c.filterList()) {
+      vec.push_back(
+          {.pszName = filter.name().get(), .pszSpec = filter.spec().get()});
+    }
+    return dialog->SetFileTypes(vec.size(), vec.data());
+  }
+  HRESULT Apply(SetFileTypeIndex const& c) {
+    return dialog->SetFileTypeIndex(c.index());
+  }
+};
+
+namespace {
+static HRESULT GetShellItemPath(IShellItem* aItem, nsString& aResultString) {
+  NS_ENSURE_TRUE(aItem, E_INVALIDARG);
+
+  mozilla::UniquePtr<wchar_t, CoTaskMemFreeDeleter> str;
+  HRESULT const hr =
+      aItem->GetDisplayName(SIGDN_FILESYSPATH, getter_Transfers(str));
+  if (SUCCEEDED(hr)) {
+    aResultString.Assign(str.get());
+  }
+  return hr;
+}
+}  // namespace
+
+#define MOZ_ENSURE_HRESULT_OK(call_)            \
+  do {                                          \
+    HRESULT const _tmp_hr_ = (call_);           \
+    if (FAILED(_tmp_hr_)) return Err(_tmp_hr_); \
+  } while (0)
+
+mozilla::Result<RefPtr<IFileDialog>, HRESULT> MakeFileDialog(
+    FileDialogType type) {
+  RefPtr<IFileDialog> dialog;
+
+  CLSID const clsid = type == FileDialogType::Open ? CLSID_FileOpenDialog
+                                                   : CLSID_FileSaveDialog;
+  HRESULT const hr = CoCreateInstance(clsid, nullptr, CLSCTX_INPROC_SERVER,
+                                      IID_IFileDialog, getter_AddRefs(dialog));
+  MOZ_ENSURE_HRESULT_OK(hr);
+
+  return std::move(dialog);
+}
+
+HRESULT ApplyCommands(::IFileDialog* dialog,
+                      nsTArray<Command> const& commands) {
+  Applicator applicator{.dialog = dialog};
+  for (auto const& cmd : commands) {
+    HRESULT const hr = applicator.Visit(cmd);
+    if (FAILED(hr)) {
+      return hr;
+    }
+  }
+  return S_OK;
+}
+
+mozilla::Result<Results, HRESULT> GetFileResults(::IFileDialog* dialog) {
+  FILEOPENDIALOGOPTIONS fos;
+  MOZ_ENSURE_HRESULT_OK(dialog->GetOptions(&fos));
+
+  using widget::WinUtils;
+
+  // Extract which filter type the user selected
+  UINT index;
+  MOZ_ENSURE_HRESULT_OK(dialog->GetFileTypeIndex(&index));
+
+  // single selection
+  if ((fos & FOS_ALLOWMULTISELECT) == 0) {
+    RefPtr<IShellItem> item;
+    MOZ_ENSURE_HRESULT_OK(dialog->GetResult(getter_AddRefs(item)));
+    if (!item) {
+      return Err(E_FAIL);
+    }
+
+    nsAutoString path;
+    MOZ_ENSURE_HRESULT_OK(GetShellItemPath(item, path));
+
+    return Results({path}, index);
+  }
+
+  // multiple selection
+  RefPtr<IFileOpenDialog> openDlg;
+  dialog->QueryInterface(IID_IFileOpenDialog, getter_AddRefs(openDlg));
+  if (!openDlg) {
+    MOZ_ASSERT(false, "a file-save dialog was given FOS_ALLOWMULTISELECT?");
+    return Err(E_UNEXPECTED);
+  }
+
+  RefPtr<IShellItemArray> items;
+  MOZ_ENSURE_HRESULT_OK(openDlg->GetResults(getter_AddRefs(items)));
+  if (!items) {
+    return Err(E_FAIL);
+  }
+
+  nsTArray<nsString> paths;
+
+  DWORD count = 0;
+  MOZ_ENSURE_HRESULT_OK(items->GetCount(&count));
+  for (DWORD idx = 0; idx < count; idx++) {
+    RefPtr<IShellItem> item;
+    MOZ_ENSURE_HRESULT_OK(items->GetItemAt(idx, getter_AddRefs(item)));
+
+    nsAutoString str;
+    MOZ_ENSURE_HRESULT_OK(GetShellItemPath(item, str));
+
+    paths.EmplaceBack(str);
+  }
+
+  return Results(std::move(paths), std::move(index));
+}
+
+mozilla::Result<nsString, HRESULT> GetFolderResults(::IFileDialog* dialog) {
+  RefPtr<IShellItem> item;
+  MOZ_ENSURE_HRESULT_OK(dialog->GetResult(getter_AddRefs(item)));
+  if (!item) {
+    // shouldn't happen -- probably a precondition failure on our part, but
+    // might be due to misbehaving shell extensions?
+    MOZ_ASSERT(false,
+               "unexpected lack of item: was `Show`'s return value checked?");
+    return Err(E_FAIL);
+  }
+
+  // If the user chose a Win7 Library, resolve to the library's
+  // default save folder.
+  RefPtr<IShellLibrary> shellLib;
+  RefPtr<IShellItem> folderPath;
+  MOZ_ENSURE_HRESULT_OK(
+      CoCreateInstance(CLSID_ShellLibrary, nullptr, CLSCTX_INPROC_SERVER,
+                       IID_IShellLibrary, getter_AddRefs(shellLib)));
+
+  if (shellLib && SUCCEEDED(shellLib->LoadLibraryFromItem(item, STGM_READ)) &&
+      SUCCEEDED(shellLib->GetDefaultSaveFolder(DSFT_DETECT, IID_IShellItem,
+                                               getter_AddRefs(folderPath)))) {
+    item.swap(folderPath);
+  }
+
+  // get the folder's file system path
+  nsAutoString str;
+  MOZ_ENSURE_HRESULT_OK(GetShellItemPath(item, str));
+  return str;
+}
+
+#undef MOZ_ENSURE_HRESULT_OK
+
+namespace detail {
+void LogProcessingError(LogModule* aModule, ipc::IProtocol* aCaller,
+                        ipc::HasResultCodes::Result aCode,
+                        const char* aReason) {
+  LogLevel const level = [&]() {
+    switch (aCode) {
+      case ipc::HasResultCodes::MsgProcessed:
+        // Normal operation. (We probably never actually get this code.)
+        return LogLevel::Verbose;
+
+      case ipc::HasResultCodes::MsgDropped:
+        return LogLevel::Verbose;
+
+      default:
+        return LogLevel::Error;
+    }
+  }();
+
+  // Processing errors are sometimes unhelpfully formatted. We can't fix that
+  // directly because the unhelpful formatting has made its way to telemetry
+  // (table `telemetry.socorro_crash`, column `ipc_channel_error`) and is being
+  // aggregated on. :(
+  nsCString reason(aReason);
+  if (reason.Last() == '\n') {
+    reason.Truncate(reason.Length() - 1);
+  }
+
+  if (MOZ_LOG_TEST(aModule, level)) {
+    const char* const side = [&]() {
+      switch (aCaller->GetSide()) {
+        case ipc::ParentSide:
+          return "parent";
+        case ipc::ChildSide:
+          return "child";
+        case ipc::UnknownSide:
+          return "unknown side";
+        default:
+          return "<illegal value>";
+      }
+    }();
+
+    const char* const errorStr = [&]() {
+      switch (aCode) {
+        case ipc::HasResultCodes::MsgProcessed:
+          return "Processed";
+        case ipc::HasResultCodes::MsgDropped:
+          return "Dropped";
+        case ipc::HasResultCodes::MsgNotKnown:
+          return "NotKnown";
+        case ipc::HasResultCodes::MsgNotAllowed:
+          return "NotAllowed";
+        case ipc::HasResultCodes::MsgPayloadError:
+          return "PayloadError";
+        case ipc::HasResultCodes::MsgProcessingError:
+          return "ProcessingError";
+        case ipc::HasResultCodes::MsgRouteError:
+          return "RouteError";
+        case ipc::HasResultCodes::MsgValueError:
+          return "ValueError";
+        default:
+          return "<illegal error type>";
+      }
+    }();
+
+    MOZ_LOG(aModule, level,
+            ("%s [%s]: IPC error (%s): %s", aCaller->GetProtocolName(), side,
+             errorStr, reason.get()));
+  }
+
+  if (level == LogLevel::Error) {
+    // kill the child process...
+    if (aCaller->GetSide() == ipc::ParentSide) {
+      // ... which isn't us
+      ipc::UtilityProcessManager::GetSingleton()->CleanShutdown(
+          ipc::SandboxingKind::WINDOWS_FILE_DIALOG);
+    } else {
+      // ... which (presumably) is us
+      CrashReporter::AnnotateCrashReport(
+          CrashReporter::Annotation::ipc_channel_error, reason);
+
+      MOZ_CRASH("IPC error");
+    }
+  }
+}
+
+// Given a (synchronous) Action returning a Result<T, HRESULT>, perform that
+// action on a new single-purpose "File Dialog" thread, with COM initialized as
+// STA. (The thread will be destroyed afterwards.)
+//
+// Returns a Promise which will resolve to T (if the action returns Ok) or
+// reject with an HRESULT (if the action either returns Err or couldn't be
+// performed).
+template <typename Res, typename Action, size_t N>
+RefPtr<Promise<Res>> SpawnFileDialogThread(const char (&where)[N],
+                                           Action action) {
+  RefPtr<nsIThread> thread;
+  {
+    nsresult rv = NS_NewNamedThread("File Dialog", getter_AddRefs(thread),
+                                    nullptr, {.isUiThread = true});
+    if (NS_FAILED(rv)) {
+      return Promise<Res>::CreateAndReject((HRESULT)rv, where);
+    }
+  }
+  // `thread` is single-purpose, and should not perform any additional work
+  // after `action`. Shut it down after we've dispatched that.
+  auto close_thread_ = MakeScopeExit([&]() {
+    auto const res = thread->AsyncShutdown();
+    static_assert(
+        std::is_same_v<uint32_t, std::underlying_type_t<decltype(res)>>);
+    if (NS_FAILED(res)) {
+      MOZ_LOG(sLogFileDialog, LogLevel::Warning,
+              ("thread->AsyncShutdown() failed: res=0x%08" PRIX32,
+               static_cast<uint32_t>(res)));
+    }
+  });
+
+  // our eventual return value
+  RefPtr promise = MakeRefPtr<typename Promise<Res>::Private>(where);
+
+  // alias to reduce indentation depth
+  auto const dispatch = [&](auto closure) {
+    return thread->DispatchToQueue(
+        NS_NewRunnableFunction(where, std::move(closure)),
+        mozilla::EventQueuePriority::Normal);
+  };
+
+  dispatch([thread, promise, where, action = std::move(action)]() {
+    // Like essentially all COM UI components, the file dialog is STA: it must
+    // be associated with a specific thread to create its HWNDs and receive
+    // messages for them. If it's launched from a thread in the multithreaded
+    // apartment (including via implicit MTA), COM will proxy out to the
+    // process's main STA thread, and the file-dialog's modal loop will run
+    // there.
+    //
+    // This of course would completely negate any point in using a separate
+    // thread, since behind the scenes the dialog would still be running on the
+    // process's main thread. In particular, under that arrangement, file
+    // dialogs (and other nested modal loops, like those performed by
+    // `SpinEventLoopUntil`) will resolve in strictly LIFO order, effectively
+    // remaining suspended until all later modal loops resolve.
+    //
+    // To avoid this, we initialize COM as STA, so that it (rather than the main
+    // STA thread) is the file dialog's "home" thread and the IFileDialog's home
+    // apartment.
+
+    mozilla::mscom::STARegion staRegion;
+    if (!staRegion) {
+      MOZ_LOG(sLogFileDialog, LogLevel::Error,
+              ("COM init failed on file dialog thread: hr = %08lx",
+               staRegion.GetHResult()));
+
+      APTTYPE at;
+      APTTYPEQUALIFIER atq;
+      HRESULT const hr = ::CoGetApartmentType(&at, &atq);
+      MOZ_LOG(sLogFileDialog, LogLevel::Error,
+              ("  current COM apartment state: hr = %08lX, APTTYPE = "
+               "%08X, APTTYPEQUALIFIER = %08X",
+               hr, at, atq));
+
+      // If this happens in the utility process, crash so we learn about it.
+      // (TODO: replace this with a telemetry ping.)
+      if (!XRE_IsParentProcess()) {
+        // Preserve relevant data on the stack for later analysis.
+        std::tuple volatile info{staRegion.GetHResult(), hr, at, atq};
+        MOZ_CRASH("Could not initialize COM STA in utility process");
+      }
+
+      // If this happens in the parent process, don't crash; just fall back to a
+      // nested modal loop. This isn't ideal, but it will probably still work
+      // well enough for the common case, wherein no other modal loops are
+      // active.
+      //
+      // (TODO: replace this with a telemetry ping, too.)
+    }
+
+    // Actually invoke the action and report the result.
+    Result<Res, HRESULT> val = action();
+    if (val.isErr()) {
+      promise->Reject(val.unwrapErr(), where);
+    } else {
+      promise->Resolve(val.unwrap(), where);
+    }
+  });
+
+  return promise;
+}
+
+// For F returning `Result<T, E>`, yields the type `T`.
+template <typename F, typename... Args>
+using inner_result_of =
+    typename std::remove_reference_t<decltype(std::declval<F>()(
+        std::declval<Args>()...))>::ok_type;
+
+template <typename ExtractorF,
+          typename RetT = inner_result_of<ExtractorF, IFileDialog*>>
+auto SpawnPickerT(HWND parent, FileDialogType type, ExtractorF&& extractor,
+                  nsTArray<Command> commands) -> RefPtr<Promise<Maybe<RetT>>> {
+  return detail::SpawnFileDialogThread<Maybe<RetT>>(
+      __PRETTY_FUNCTION__,
+      [=, commands = std::move(commands)]() -> Result<Maybe<RetT>, HRESULT> {
+        // On Win10, the picker doesn't support per-monitor DPI, so we create it
+        // with our context set temporarily to system-dpi-aware.
+        WinUtils::AutoSystemDpiAware dpiAwareness;
+
+        RefPtr<IFileDialog> dialog;
+        MOZ_TRY_VAR(dialog, MakeFileDialog(type));
+
+        if (HRESULT const rv = ApplyCommands(dialog, commands); FAILED(rv)) {
+          return mozilla::Err(rv);
+        }
+
+        if (HRESULT const rv = dialog->Show(parent); FAILED(rv)) {
+          if (rv == HRESULT_FROM_WIN32(ERROR_CANCELLED)) {
+            return Result<Maybe<RetT>, HRESULT>(Nothing());
+          }
+          return mozilla::Err(rv);
+        }
+
+        RetT res;
+        MOZ_TRY_VAR(res, extractor(dialog.get()));
+
+        return Some(res);
+      });
+}
+
+}  // namespace detail
+
+RefPtr<Promise<Maybe<Results>>> SpawnFilePicker(HWND parent,
+                                                FileDialogType type,
+                                                nsTArray<Command> commands) {
+  return detail::SpawnPickerT(parent, type, GetFileResults,
+                              std::move(commands));
+}
+
+RefPtr<Promise<Maybe<nsString>>> SpawnFolderPicker(HWND parent,
+                                                   nsTArray<Command> commands) {
+  return detail::SpawnPickerT(parent, FileDialogType::Open, GetFolderResults,
+                              std::move(commands));
+}
+
+}  // namespace mozilla::widget::filedialog
diff --git a/widget/windows/filedialog/WinFileDialogCommands.h b/widget/windows/filedialog/WinFileDialogCommands.h
new file mode 100644
index 0000000000..ca4561a8f2
--- /dev/null
+++ b/widget/windows/filedialog/WinFileDialogCommands.h
@@ -0,0 +1,74 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_filedialog_WinFileDialogCommands_h__
+#define widget_windows_filedialog_WinFileDialogCommands_h__
+
+#include "ipc/EnumSerializer.h"
+#include "mozilla/Logging.h"
+#include "mozilla/MozPromise.h"
+#include "mozilla/ipc/MessageLink.h"
+#include "mozilla/widget/filedialog/WinFileDialogCommandsDefn.h"
+
+// Windows interface types, defined in <shobjidl.h>
+struct IFileDialog;
+struct IFileOpenDialog;
+
+namespace mozilla::widget::filedialog {
+
+extern LazyLogModule sLogFileDialog;
+
+enum class FileDialogType : uint8_t { Open, Save };
+
+// Create a file-dialog of the relevant type. Requires MSCOM to be initialized.
+mozilla::Result<RefPtr<IFileDialog>, HRESULT> MakeFileDialog(FileDialogType);
+
+// Apply the selected commands to the IFileDialog, in preparation for showing
+// it. (The actual showing step is left to the caller.)
+[[nodiscard]] HRESULT ApplyCommands(::IFileDialog*,
+                                    nsTArray<Command> const& commands);
+
+// Extract one or more results from the file-picker dialog.
+//
+// Requires that Show() has been called and has returned S_OK.
+mozilla::Result<Results, HRESULT> GetFileResults(::IFileDialog*);
+
+// Extract the chosen folder from the folder-picker dialog.
+//
+// Requires that Show() has been called and has returned S_OK.
+mozilla::Result<nsString, HRESULT> GetFolderResults(::IFileDialog*);
+
+namespace detail {
+// Log the error. If it's a notable error, kill the child process.
+void LogProcessingError(LogModule* aModule, ipc::IProtocol* aCaller,
+                        ipc::HasResultCodes::Result aCode, const char* aReason);
+
+}  // namespace detail
+
+template <typename R>
+using Promise = MozPromise<R, HRESULT, true>;
+
+// Show a file-picker on another thread in the current process.
+RefPtr<Promise<Maybe<Results>>> SpawnFilePicker(HWND parent,
+                                                FileDialogType type,
+                                                nsTArray<Command> commands);
+
+// Show a folder-picker on another thread in the current process.
+RefPtr<Promise<Maybe<nsString>>> SpawnFolderPicker(HWND parent,
+                                                   nsTArray<Command> commands);
+
+}  // namespace mozilla::widget::filedialog
+
+namespace IPC {
+template <>
+struct ParamTraits<mozilla::widget::filedialog::FileDialogType>
+    : public ContiguousEnumSerializerInclusive<
+          mozilla::widget::filedialog::FileDialogType,
+          mozilla::widget::filedialog::FileDialogType::Open,
+          mozilla::widget::filedialog::FileDialogType::Save> {};
+}  // namespace IPC
+
+#endif  // widget_windows_filedialog_WinFileDialogCommands_h__
diff --git a/widget/windows/filedialog/WinFileDialogCommandsDefn.ipdlh b/widget/windows/filedialog/WinFileDialogCommandsDefn.ipdlh
new file mode 100644
index 0000000000..dd85942f24
--- /dev/null
+++ b/widget/windows/filedialog/WinFileDialogCommandsDefn.ipdlh
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=ipdl : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+namespace mozilla {
+namespace widget {
+namespace filedialog {
+
+// Commands corresponding to the various functions in IFileDialog (or at least
+// the ones we actually make use of).
+//
+// All commands' semantics are direct parallels of their equivalently-named
+// functions on IFileDialog, with the only changes being those necessary to use
+// IPDLable representation-datatypes. (Thus, e.g., `SetOptions` effectively
+// takes a `FILEOPENDIALOGOPTIONS`, and `SetFileTypeIndex` is 1-based.)
+struct SetOptions          { uint32_t options; };
+struct SetTitle            { nsString title; };
+struct SetOkButtonLabel    { nsString label; };
+struct SetFolder           { nsString path; };
+struct SetFileName         { nsString filename; };
+struct SetDefaultExtension { nsString extension; };
+struct ComDlgFilterSpec    { nsString name; nsString spec; };
+struct SetFileTypes        { ComDlgFilterSpec[] filterList; };
+struct SetFileTypeIndex    { uint32_t index; };
+
+// Union of the above.
+union Command {
+  SetOptions;
+  SetTitle;
+  SetOkButtonLabel;
+  SetFolder;
+  SetFileName;
+  SetDefaultExtension;
+  SetFileTypes;
+  SetFileTypeIndex;
+};
+
+// The results from opening a file dialog. (Note that folder selection only
+// returns an nsString.)
+struct Results {
+  nsString[] paths;
+  uint32_t selectedFileTypeIndex;
+};
+
+} // namespace filedialog
+} // namespace widget
+} // namespace mozilla
diff --git a/widget/windows/filedialog/WinFileDialogParent.cpp b/widget/windows/filedialog/WinFileDialogParent.cpp
new file mode 100644
index 0000000000..2c256a1506
--- /dev/null
+++ b/widget/windows/filedialog/WinFileDialogParent.cpp
@@ -0,0 +1,94 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/widget/filedialog/WinFileDialogParent.h"
+
+#include "mozilla/Logging.h"
+#include "mozilla/Result.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "mozilla/ipc/UtilityProcessManager.h"
+#include "nsISupports.h"
+
+namespace mozilla::widget::filedialog {
+
+// Count of currently-open file dialogs (not just open-file dialogs).
+static size_t sOpenDialogActors = 0;
+
+WinFileDialogParent::WinFileDialogParent() {
+  MOZ_LOG(sLogFileDialog, LogLevel::Debug,
+          ("%s %p", __PRETTY_FUNCTION__, this));
+}
+
+WinFileDialogParent::~WinFileDialogParent() {
+  MOZ_LOG(sLogFileDialog, LogLevel::Debug,
+          ("%s %p", __PRETTY_FUNCTION__, this));
+}
+
+PWinFileDialogParent::nsresult WinFileDialogParent::BindToUtilityProcess(
+    mozilla::ipc::UtilityProcessParent* aUtilityParent) {
+  Endpoint<PWinFileDialogParent> parentEnd;
+  Endpoint<PWinFileDialogChild> childEnd;
+  nsresult rv = PWinFileDialog::CreateEndpoints(base::GetCurrentProcId(),
+                                                aUtilityParent->OtherPid(),
+                                                &parentEnd, &childEnd);
+
+  if (NS_FAILED(rv)) {
+    MOZ_ASSERT(false, "Protocol endpoints failure");
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!aUtilityParent->SendStartWinFileDialogService(std::move(childEnd))) {
+    MOZ_ASSERT(false, "SendStartWinFileDialogService failed");
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!parentEnd.Bind(this)) {
+    MOZ_ASSERT(false, "parentEnd.Bind failed");
+    return NS_ERROR_FAILURE;
+  }
+
+  sOpenDialogActors++;
+  return NS_OK;
+}
+
+void WinFileDialogParent::ProcessingError(Result aCode, const char* aReason) {
+  detail::LogProcessingError(sLogFileDialog, this, aCode, aReason);
+}
+
+ProcessProxy::ProcessProxy(RefPtr<WFDP>&& obj)
+    : data(MakeRefPtr<Contents>(std::move(obj))) {}
+
+ProcessProxy::Contents::Contents(RefPtr<WFDP>&& obj) : ptr(std::move(obj)) {}
+
+ProcessProxy::Contents::~Contents() {
+  AssertIsOnMainThread();
+
+  // destroy the actor...
+  ptr->Close();
+
+  // ... and possibly the process
+  if (!--sOpenDialogActors) {
+    StopProcess();
+  }
+}
+
+void ProcessProxy::Contents::StopProcess() {
+  auto const upm = ipc::UtilityProcessManager::GetSingleton();
+  if (!upm) {
+    // This is only possible when the UtilityProcessManager has shut down -- in
+    // which case the file-dialog process has also already been directed to shut
+    // down, and there's nothing we need to do here.
+    return;
+  }
+
+  MOZ_LOG(sLogFileDialog, LogLevel::Debug,
+          ("%s: killing the WINDOWS_FILE_DIALOG process (no more live "
+           "actors)",
+           __PRETTY_FUNCTION__));
+  upm->CleanShutdown(ipc::SandboxingKind::WINDOWS_FILE_DIALOG);
+}
+
+}  // namespace mozilla::widget::filedialog
diff --git a/widget/windows/filedialog/WinFileDialogParent.h b/widget/windows/filedialog/WinFileDialogParent.h
new file mode 100644
index 0000000000..a2c1197c55
--- /dev/null
+++ b/widget/windows/filedialog/WinFileDialogParent.h
@@ -0,0 +1,90 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_filedialog_WinFileDialogParent_h__
+#define widget_windows_filedialog_WinFileDialogParent_h__
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/MozPromise.h"
+#include "mozilla/ProcInfo.h"
+#include "mozilla/Result.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "mozilla/dom/ChromeUtilsBinding.h"
+#include "mozilla/ipc/UtilityProcessParent.h"
+#include "mozilla/widget/filedialog/PWinFileDialogParent.h"
+#include "nsISupports.h"
+#include "nsStringFwd.h"
+
+namespace mozilla::widget::filedialog {
+
+class WinFileDialogParent : public PWinFileDialogParent {
+ public:
+  using UtilityActorName = ::mozilla::UtilityActorName;
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WinFileDialogParent, override);
+
+ public:
+  WinFileDialogParent();
+  nsresult BindToUtilityProcess(
+      mozilla::ipc::UtilityProcessParent* aUtilityParent);
+
+  UtilityActorName GetActorName() {
+    return UtilityActorName::WindowsFileDialog;
+  }
+
+ private:
+  ~WinFileDialogParent();
+
+  void ProcessingError(Result aCode, const char* aReason) override;
+};
+
+// Proxy for the WinFileDialog process and actor.
+//
+// The IPC subsystem holds a strong reference to all IPC actors, so releasing
+// the last RefPtr for such an actor does not actually cause the actor to be
+// destroyed. Similarly, the UtilityProcessManager owns the host process for an
+// actor, and merely destroying all actors within that host process will not
+// cause it to be reaped.
+//
+// This object, then, acts as a proxy for those objects' lifetimes: when the
+// last reference to `Contents` is released, the necessary explicit cleanup of
+// the actor (and, if possible, the host process) will be performed.
+class ProcessProxy {
+ public:
+  using WFDP = WinFileDialogParent;
+
+  explicit ProcessProxy(RefPtr<WFDP>&& obj);
+  ~ProcessProxy() = default;
+
+  explicit operator bool() const { return data->ptr && data->ptr->CanSend(); }
+  bool operator!() const { return !bool(*this); }
+
+  WFDP& operator*() const { return *data->ptr; }
+  WFDP* operator->() const { return data->ptr; }
+  WFDP* get() const { return data->ptr; }
+
+  ProcessProxy(ProcessProxy const& that) = default;
+  ProcessProxy(ProcessProxy&&) = default;
+
+ private:
+  struct Contents {
+    NS_INLINE_DECL_REFCOUNTING(Contents);
+
+   public:
+    explicit Contents(RefPtr<WFDP>&& obj);
+    RefPtr<WFDP> const ptr;
+
+   private:
+    ~Contents();
+    void StopProcess();
+  };
+  // guaranteed nonnull
+  RefPtr<Contents> data;
+};
+
+}  // namespace mozilla::widget::filedialog
+
+#endif  // widget_windows_filedialog_WinFileDialogParent_h__
diff --git a/widget/windows/filedialog/moz.build b/widget/windows/filedialog/moz.build
new file mode 100644
index 0000000000..d2732faf78
--- /dev/null
+++ b/widget/windows/filedialog/moz.build
@@ -0,0 +1,27 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+IPDL_SOURCES += [
+    "PWinFileDialog.ipdl",
+    "WinFileDialogCommandsDefn.ipdlh",
+]
+
+UNIFIED_SOURCES += [
+    "WinFileDialogChild.cpp",
+    "WinFileDialogCommands.cpp",
+    "WinFileDialogParent.cpp",
+]
+
+EXPORTS.mozilla.widget.filedialog += [
+    "WinFileDialogChild.h",
+    "WinFileDialogCommands.h",
+    "WinFileDialogParent.h",
+]
+
+# needed for IPC header files
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
diff --git a/widget/windows/metrics.yaml b/widget/windows/metrics.yaml
new file mode 100644
index 0000000000..e9d3b4f5cf
--- /dev/null
+++ b/widget/windows/metrics.yaml
@@ -0,0 +1,58 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Adding a new metric? We have docs for that!
+# https://firefox-source-docs.mozilla.org/toolkit/components/glean/user/new_definitions_file.html
+
+---
+$schema: moz://mozilla.org/schemas/glean/metrics/2-0-0
+$tags:
+  - 'Core :: Widget: Win32'
+
+file_dialog:
+  fallback:
+    type: event
+    description: >
+      Records the result of an attempt to open and use the out-of-process file
+      dialog when the in-process file-dialog is available as a fallback.
+    metadata:
+      # mostly technical, but includes timing data that may derive from user
+      # interactions
+      data-sensitivity: [technical, interaction]
+    notification_emails:
+      - rkraesig@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1872397
+    # this event may alternatively be manually expired once bug 1677170 is
+    # closed
+    expires: 135
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1872397#c7
+    extra_keys:
+      succeeded:
+        type: boolean
+        description: >
+          Whether the out-of-process dialog succeeded or failed. (Note that
+          user-induced cancellation is considered a form of success.)
+      time_remote:
+        type: quantity
+        description: >
+          The time between the out-of-process file dialog's instantiation
+          attempt and its failure, in milliseconds.
+      hresult_remote:
+        type: string
+        description: >
+          The failure code produced by the out-of-process file dialog, formatted
+          as eight hexdigits. Only present when `!succeeded`.
+      time_local:
+        type: quantity
+        description: >
+          The time between the in-process file dialog's instantiation attempt
+          and its conclusion (successfully or otherwise), in milliseconds. Only
+          present when `!succeeded`.
+      hresult_local:
+        type: string
+        description: >
+          The return code produced by the in-process file dialog, formatted as
+          eight hexdigits. Only present when `!succeeded`.
diff --git a/widget/windows/moz.build b/widget/windows/moz.build
new file mode 100644
index 0000000000..f19a46caf1
--- /dev/null
+++ b/widget/windows/moz.build
@@ -0,0 +1,213 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "Widget: Win32")
+    SCHEDULES.exclusive = ["windows"]
+
+with Files("*CompositorWidget*"):
+    BUG_COMPONENT = ("Core", "Graphics")
+
+with Files("*IMEHandler*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*IMMHandler*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*KeyboardLayout*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("OSK*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+with Files("*TSFTextStore*"):
+    BUG_COMPONENT = ("Core", "DOM: UI Events & Focus Handling")
+
+DIRS += [
+    "filedialog",
+]
+
+TEST_DIRS += ["tests"]
+
+EXPORTS += [
+    "nsdefs.h",
+    "WindowHook.h",
+    "WinUtils.h",
+]
+
+EXPORTS.mozilla += [
+    "ShellHeaderOnlyUtils.h",
+    "ToastNotificationHeaderOnlyUtils.h",
+    "UrlmonHeaderOnlyUtils.h",
+    "WindowsConsole.h",
+    "WindowsEventLog.h",
+    "WinHeaderOnlyUtils.h",
+]
+
+EXPORTS.mozilla.widget += [
+    "AudioSession.h",
+    "CompositorWidgetChild.h",
+    "CompositorWidgetParent.h",
+    "InProcessWinCompositorWidget.h",
+    "JumpListBuilder.h",
+    "nsWindowLoggedMessages.h",
+    "WinCompositorWidget.h",
+    "WinCompositorWindowThread.h",
+    "WindowsEMF.h",
+    "WindowsSMTCProvider.h",
+    "WinEventObserver.h",
+    "WinMessages.h",
+    "WinModifierKeyState.h",
+    "WinRegistry.h",
+    "WinTaskbar.h",
+    "WinWindowOcclusionTracker.h",
+]
+
+UNIFIED_SOURCES += [
+    "AudioSession.cpp",
+    "CompositorWidgetChild.cpp",
+    "DirectManipulationOwner.cpp",
+    "GfxInfo.cpp",
+    "IEnumFE.cpp",
+    "IMMHandler.cpp",
+    "JumpListBuilder.cpp",
+    "KeyboardLayout.cpp",
+    "LegacyJumpListItem.cpp",
+    "LSPAnnotator.cpp",
+    "nsAppShell.cpp",
+    "nsClipboard.cpp",
+    "nsColorPicker.cpp",
+    "nsDataObj.cpp",
+    "nsDataObjCollection.cpp",
+    "nsDragService.cpp",
+    "nsLookAndFeel.cpp",
+    "nsNativeDragSource.cpp",
+    "nsNativeDragTarget.cpp",
+    "nsNativeThemeWin.cpp",
+    "nsSound.cpp",
+    "nsToolkit.cpp",
+    "nsUserIdleServiceWin.cpp",
+    "nsUXThemeData.cpp",
+    "nsWindow.cpp",
+    "nsWindowDbg.cpp",
+    "nsWindowGfx.cpp",
+    "nsWindowLoggedMessages.cpp",
+    "nsWindowTaskbarConcealer.cpp",
+    "nsWinGesture.cpp",
+    "OSKTabTipManager.cpp",
+    "OSKVRManager.cpp",
+    "RemoteBackbuffer.cpp",
+    "ScreenHelperWin.cpp",
+    "SystemStatusBar.cpp",
+    "TaskbarPreview.cpp",
+    "TaskbarPreviewButton.cpp",
+    "TaskbarTabPreview.cpp",
+    "TaskbarWindowPreview.cpp",
+    "WidgetTraceEvent.cpp",
+    "WinCompositorWindowThread.cpp",
+    "WindowHook.cpp",
+    "WindowsConsole.cpp",
+    "WinEventObserver.cpp",
+    "WinIMEHandler.cpp",
+    "WinPointerEvents.cpp",
+    "WinRegistry.cpp",
+    "WinTaskbar.cpp",
+    "WinTextEventDispatcherListener.cpp",
+    "WinUtils.cpp",
+    "WinWindowOcclusionTracker.cpp",
+]
+
+# The following files cannot be built in unified mode because of name clashes.
+SOURCES += [
+    "CompositorWidgetParent.cpp",
+    "InProcessWinCompositorWidget.cpp",
+    "LegacyJumpListBuilder.cpp",
+    "MediaKeysEventSourceFactory.cpp",
+    "nsBidiKeyboard.cpp",
+    "nsFilePicker.cpp",
+    "nsSharePicker.cpp",
+    "nsWidgetFactory.cpp",
+    "OSKInputPaneManager.cpp",
+    "WinCompositorWidget.cpp",
+    "WindowsSMTCProvider.cpp",
+    "WindowsUIUtils.cpp",
+    "WinMouseScrollHandler.cpp",
+]
+
+# Needs INITGUID and we don't allow INITGUID in unified sources since bug 970429.
+SOURCES += [
+    "InputDeviceUtils.cpp",
+    "TSFTextStore.cpp",
+]
+
+if CONFIG["NS_PRINTING"]:
+    UNIFIED_SOURCES += [
+        "nsDeviceContextSpecWin.cpp",
+        "nsPrintDialogWin.cpp",
+        "nsPrinterWin.cpp",
+        "nsPrintSettingsServiceWin.cpp",
+        "nsPrintSettingsWin.cpp",
+    ]
+    SOURCES += [
+        "nsPrintDialogUtil.cpp",
+    ]
+
+if CONFIG["MOZ_ENABLE_SKIA_PDF"]:
+    UNIFIED_SOURCES += [
+        "WindowsEMF.cpp",
+    ]
+
+XPCOM_MANIFESTS += [
+    "components.conf",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
+
+if CONFIG["MOZ_ENABLE_SKIA_PDF"]:
+    LOCAL_INCLUDES += CONFIG["SKIA_INCLUDES"]
+
+LOCAL_INCLUDES += [
+    "/gfx/cairo/cairo/src",
+    "/layout/forms",
+    "/layout/generic",
+    "/layout/style",
+    "/layout/xul",
+    "/toolkit/components/jsoncpp/include",
+    "/toolkit/xre",
+    "/widget",
+    "/widget/headless",
+    "/xpcom/base",
+]
+
+DEFINES["MOZ_UNICODE"] = True
+DEFINES["MOZ_APP_NAME"] = '"%s"' % CONFIG["MOZ_APP_NAME"]
+# Turn `firefox` into `Firefox`.
+DEFINES["MOZ_TOAST_APP_NAME"] = '"%s"' % CONFIG["MOZ_APP_NAME"].title()
+
+for var in ("MOZ_ENABLE_D3D10_LAYER",):
+    if CONFIG[var]:
+        DEFINES[var] = True
+
+USE_LIBS += [
+    "jsoncpp",
+]
+
+OS_LIBS += [
+    "ktmw32",
+    "rpcrt4",
+    "urlmon",
+]
+
+# mingw is missing Windows toast notification definitions.
+if CONFIG["CC_TYPE"] == "clang-cl":
+    SOURCES += [
+        "ToastNotification.cpp",
+        "ToastNotificationHandler.cpp",
+    ]
+
+SPHINX_TREES["/widget/windows"] = "docs"
diff --git a/widget/windows/nsAppShell.cpp b/widget/windows/nsAppShell.cpp
new file mode 100644
index 0000000000..314176766d
--- /dev/null
+++ b/widget/windows/nsAppShell.cpp
@@ -0,0 +1,1000 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Attributes.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/ipc/MessageChannel.h"
+#include "mozilla/ipc/WindowsMessageLoop.h"
+#include "nsAppShell.h"
+#include "nsToolkit.h"
+#include "nsThreadUtils.h"
+#include "WinUtils.h"
+#include "WinTaskbar.h"
+#include "WinMouseScrollHandler.h"
+#include "nsWindowDefs.h"
+#include "nsWindow.h"
+#include "nsString.h"
+#include "WinIMEHandler.h"
+#include "mozilla/widget/AudioSession.h"
+#include "mozilla/BackgroundHangMonitor.h"
+#include "mozilla/Hal.h"
+#include "nsIDOMWakeLockListener.h"
+#include "nsIPowerManagerService.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/StaticPtr.h"
+#include "nsTHashtable.h"
+#include "nsHashKeys.h"
+#include "nsComponentManagerUtils.h"
+#include "ScreenHelperWin.h"
+#include "HeadlessScreenHelper.h"
+#include "mozilla/widget/ScreenManager.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/NativeNt.h"
+#include "mozilla/WindowsProcessMitigations.h"
+
+#include <winternl.h>
+
+#ifdef MOZ_BACKGROUNDTASKS
+#  include "mozilla/BackgroundTasks.h"
+#endif
+
+#if defined(ACCESSIBILITY)
+#  include "mozilla/a11y/Compatibility.h"
+#  include "mozilla/a11y/Platform.h"
+#endif  // defined(ACCESSIBILITY)
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+#define WAKE_LOCK_LOG(...) \
+  MOZ_LOG(gWinWakeLockLog, mozilla::LogLevel::Debug, (__VA_ARGS__))
+static mozilla::LazyLogModule gWinWakeLockLog("WinWakeLock");
+
+// This wakelock listener is used for Window7 and above.
+class WinWakeLockListener final : public nsIDOMMozWakeLockListener {
+ public:
+  NS_DECL_ISUPPORTS
+  WinWakeLockListener() { MOZ_ASSERT(XRE_IsParentProcess()); }
+
+ private:
+  ~WinWakeLockListener() {
+    ReleaseWakelockIfNeeded(PowerRequestDisplayRequired);
+    ReleaseWakelockIfNeeded(PowerRequestExecutionRequired);
+  }
+
+  void SetHandle(HANDLE aHandle, POWER_REQUEST_TYPE aType) {
+    switch (aType) {
+      case PowerRequestDisplayRequired: {
+        if (!aHandle && mDisplayHandle) {
+          CloseHandle(mDisplayHandle);
+        }
+        mDisplayHandle = aHandle;
+        return;
+      }
+      case PowerRequestExecutionRequired: {
+        if (!aHandle && mNonDisplayHandle) {
+          CloseHandle(mNonDisplayHandle);
+        }
+        mNonDisplayHandle = aHandle;
+        return;
+      }
+      default:
+        MOZ_ASSERT_UNREACHABLE("Invalid request type");
+        return;
+    }
+  }
+
+  HANDLE GetHandle(POWER_REQUEST_TYPE aType) const {
+    switch (aType) {
+      case PowerRequestDisplayRequired:
+        return mDisplayHandle;
+      case PowerRequestExecutionRequired:
+        return mNonDisplayHandle;
+      default:
+        MOZ_ASSERT_UNREACHABLE("Invalid request type");
+        return nullptr;
+    }
+  }
+
+  HANDLE CreateHandle(POWER_REQUEST_TYPE aType) {
+    MOZ_ASSERT(!GetHandle(aType));
+    REASON_CONTEXT context = {0};
+    context.Version = POWER_REQUEST_CONTEXT_VERSION;
+    context.Flags = POWER_REQUEST_CONTEXT_SIMPLE_STRING;
+    context.Reason.SimpleReasonString = RequestTypeLPWSTR(aType);
+    HANDLE handle = PowerCreateRequest(&context);
+    if (!handle) {
+      WAKE_LOCK_LOG("Failed to create handle for %s, error=%lu",
+                    RequestTypeStr(aType), GetLastError());
+      return nullptr;
+    }
+    SetHandle(handle, aType);
+    return handle;
+  }
+
+  LPWSTR RequestTypeLPWSTR(POWER_REQUEST_TYPE aType) const {
+    switch (aType) {
+      case PowerRequestDisplayRequired:
+        return const_cast<LPWSTR>(L"display request");  // -Wwritable-strings
+      case PowerRequestExecutionRequired:
+        return const_cast<LPWSTR>(
+            L"non-display request");  // -Wwritable-strings
+      default:
+        MOZ_ASSERT_UNREACHABLE("Invalid request type");
+        return const_cast<LPWSTR>(L"unknown");  // -Wwritable-strings
+    }
+  }
+
+  const char* RequestTypeStr(POWER_REQUEST_TYPE aType) const {
+    switch (aType) {
+      case PowerRequestDisplayRequired:
+        return "display request";
+      case PowerRequestExecutionRequired:
+        return "non-display request";
+      default:
+        MOZ_ASSERT_UNREACHABLE("Invalid request type");
+        return "unknown";
+    }
+  }
+
+  void RequestWakelockIfNeeded(POWER_REQUEST_TYPE aType) {
+    if (GetHandle(aType)) {
+      WAKE_LOCK_LOG("Already requested lock for %s", RequestTypeStr(aType));
+      return;
+    }
+
+    WAKE_LOCK_LOG("Prepare a wakelock for %s", RequestTypeStr(aType));
+    HANDLE handle = CreateHandle(aType);
+    if (!handle) {
+      WAKE_LOCK_LOG("Failed due to no handle for %s", RequestTypeStr(aType));
+      return;
+    }
+
+    if (PowerSetRequest(handle, aType)) {
+      WAKE_LOCK_LOG("Requested %s lock", RequestTypeStr(aType));
+    } else {
+      WAKE_LOCK_LOG("Failed to request %s lock, error=%lu",
+                    RequestTypeStr(aType), GetLastError());
+      SetHandle(nullptr, aType);
+    }
+  }
+
+  void ReleaseWakelockIfNeeded(POWER_REQUEST_TYPE aType) {
+    if (!GetHandle(aType)) {
+      WAKE_LOCK_LOG("Already released lock for %s", RequestTypeStr(aType));
+      return;
+    }
+
+    WAKE_LOCK_LOG("Prepare to release wakelock for %s", RequestTypeStr(aType));
+    if (!PowerClearRequest(GetHandle(aType), aType)) {
+      WAKE_LOCK_LOG("Failed to release %s lock, error=%lu",
+                    RequestTypeStr(aType), GetLastError());
+      return;
+    }
+    SetHandle(nullptr, aType);
+    WAKE_LOCK_LOG("Released wakelock for %s", RequestTypeStr(aType));
+  }
+
+  NS_IMETHOD Callback(const nsAString& aTopic,
+                      const nsAString& aState) override {
+    WAKE_LOCK_LOG("topic=%s, state=%s", NS_ConvertUTF16toUTF8(aTopic).get(),
+                  NS_ConvertUTF16toUTF8(aState).get());
+    if (!aTopic.EqualsASCII("screen") && !aTopic.EqualsASCII("audio-playing") &&
+        !aTopic.EqualsASCII("video-playing")) {
+      return NS_OK;
+    }
+
+    const bool isNonDisplayLock = aTopic.EqualsASCII("audio-playing");
+    bool requestLock = false;
+    if (isNonDisplayLock) {
+      requestLock = aState.EqualsASCII("locked-foreground") ||
+                    aState.EqualsASCII("locked-background");
+    } else {
+      requestLock = aState.EqualsASCII("locked-foreground");
+    }
+
+    if (isNonDisplayLock) {
+      if (requestLock) {
+        RequestWakelockIfNeeded(PowerRequestExecutionRequired);
+      } else {
+        ReleaseWakelockIfNeeded(PowerRequestExecutionRequired);
+      }
+    } else {
+      if (requestLock) {
+        RequestWakelockIfNeeded(PowerRequestDisplayRequired);
+      } else {
+        ReleaseWakelockIfNeeded(PowerRequestDisplayRequired);
+      }
+    }
+    return NS_OK;
+  }
+
+  // Handle would only exist when we request wakelock successfully.
+  HANDLE mDisplayHandle = nullptr;
+  HANDLE mNonDisplayHandle = nullptr;
+};
+NS_IMPL_ISUPPORTS(WinWakeLockListener, nsIDOMMozWakeLockListener)
+StaticRefPtr<nsIDOMMozWakeLockListener> sWakeLockListener;
+
+static void AddScreenWakeLockListener() {
+  nsCOMPtr<nsIPowerManagerService> sPowerManagerService =
+      do_GetService(POWERMANAGERSERVICE_CONTRACTID);
+  if (sPowerManagerService) {
+    sWakeLockListener = new WinWakeLockListener();
+    sPowerManagerService->AddWakeLockListener(sWakeLockListener);
+  } else {
+    NS_WARNING(
+        "Failed to retrieve PowerManagerService, wakelocks will be broken!");
+  }
+}
+
+static void RemoveScreenWakeLockListener() {
+  nsCOMPtr<nsIPowerManagerService> sPowerManagerService =
+      do_GetService(POWERMANAGERSERVICE_CONTRACTID);
+  if (sPowerManagerService) {
+    sPowerManagerService->RemoveWakeLockListener(sWakeLockListener);
+    sPowerManagerService = nullptr;
+    sWakeLockListener = nullptr;
+  }
+}
+
+class SingleNativeEventPump final : public nsIThreadObserver {
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSITHREADOBSERVER
+
+  SingleNativeEventPump() {
+    MOZ_ASSERT(!XRE_UseNativeEventProcessing(),
+               "Should only be used when not properly processing events.");
+  }
+
+ private:
+  ~SingleNativeEventPump() {}
+};
+
+NS_IMPL_ISUPPORTS(SingleNativeEventPump, nsIThreadObserver)
+
+NS_IMETHODIMP
+SingleNativeEventPump::OnDispatchedEvent() { return NS_OK; }
+
+NS_IMETHODIMP
+SingleNativeEventPump::OnProcessNextEvent(nsIThreadInternal* aThread,
+                                          bool aMayWait) {
+  MSG msg;
+  bool gotMessage = WinUtils::PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE);
+  if (gotMessage) {
+    ::TranslateMessage(&msg);
+    ::DispatchMessageW(&msg);
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+SingleNativeEventPump::AfterProcessNextEvent(nsIThreadInternal* aThread,
+                                             bool aMayWait) {
+  return NS_OK;
+}
+
+// RegisterWindowMessage values
+// Native event callback message
+const wchar_t* kAppShellGeckoEventId = L"nsAppShell:EventID";
+UINT sAppShellGeckoMsgId = 0x10001;  // initialize to invalid message ID
+// Taskbar button creation message
+const wchar_t* kTaskbarButtonEventId = L"TaskbarButtonCreated";
+UINT sTaskbarButtonCreatedMsg = 0x10002;  // initialize to invalid message ID
+
+/* static */
+UINT nsAppShell::GetTaskbarButtonCreatedMessage() {
+  return sTaskbarButtonCreatedMsg;
+}
+
+namespace mozilla {
+namespace crashreporter {
+void LSPAnnotate();
+}  // namespace crashreporter
+}  // namespace mozilla
+
+using mozilla::crashreporter::LSPAnnotate;
+
+//-------------------------------------------------------------------------
+
+// Note that since we're on x86-ish processors here, ReleaseAcquire is the
+// semantics that normal loads and stores would use anyway.
+static Atomic<size_t, ReleaseAcquire> sOutstandingNativeEventCallbacks;
+
+/*static*/ LRESULT CALLBACK nsAppShell::EventWindowProc(HWND hwnd, UINT uMsg,
+                                                        WPARAM wParam,
+                                                        LPARAM lParam) {
+  NativeEventLogger eventLogger("AppShell", hwnd, uMsg, wParam, lParam);
+
+  if (uMsg == sAppShellGeckoMsgId) {
+    // The app shell might have been destroyed between this message being
+    // posted and being executed, so be extra careful.
+    if (!sOutstandingNativeEventCallbacks) {
+      return TRUE;
+    }
+
+    nsAppShell* as = reinterpret_cast<nsAppShell*>(lParam);
+    as->NativeEventCallback();
+    --sOutstandingNativeEventCallbacks;
+    return TRUE;
+  }
+
+  LRESULT ret = DefWindowProc(hwnd, uMsg, wParam, lParam);
+  eventLogger.SetResult(ret, false);
+  return ret;
+}
+
+nsAppShell::~nsAppShell() {
+  hal::Shutdown();
+
+  if (mEventWnd) {
+    // DestroyWindow doesn't do anything when called from a non UI thread.
+    // Since mEventWnd was created on the UI thread, it must be destroyed on
+    // the UI thread.
+    SendMessage(mEventWnd, WM_CLOSE, 0, 0);
+  }
+
+  // Cancel any outstanding native event callbacks.
+  sOutstandingNativeEventCallbacks = 0;
+}
+
+NS_IMETHODIMP
+nsAppShell::Observe(nsISupports* aSubject, const char* aTopic,
+                    const char16_t* aData) {
+  if (XRE_IsParentProcess()) {
+    nsCOMPtr<nsIObserverService> obsServ(
+        mozilla::services::GetObserverService());
+
+    if (!strcmp(aTopic, "sessionstore-restoring-on-startup")) {
+      nsWindow::SetIsRestoringSession(true);
+      // Now that we've handled the observer notification, we can remove it
+      obsServ->RemoveObserver(this, "sessionstore-restoring-on-startup");
+      return NS_OK;
+    }
+
+    if (!strcmp(aTopic, "sessionstore-windows-restored")) {
+      nsWindow::SetIsRestoringSession(false);
+      // Now that we've handled the observer notification, we can remove it
+      obsServ->RemoveObserver(this, "sessionstore-windows-restored");
+      return NS_OK;
+    }
+  }
+
+  return nsBaseAppShell::Observe(aSubject, aTopic, aData);
+}
+
+namespace {
+
+// Struct storing the visible, loggable error-state of a Windows thread.
+// Approximately `std:pair(::GetLastError(), ::RtlGetLastNtStatus())`.
+//
+// Uses sentinel values rather than a proper `Maybe` type to simplify
+// minidump-analysis.
+struct WinErrorState {
+  // Last error, as provided by ::GetLastError().
+  DWORD error = ~0;
+  // Last NTSTATUS, as provided by the TIB.
+  NTSTATUS ntStatus = ~0;
+
+ private:
+  // per WINE et al.; stable since NT 3.51
+  constexpr static size_t kLastNtStatusOffset =
+      sizeof(size_t) == 8 ? 0x1250 : 0xbf4;
+
+  static void SetLastNtStatus(NTSTATUS status) {
+    auto* teb = ::NtCurrentTeb();
+    *reinterpret_cast<NTSTATUS*>(reinterpret_cast<char*>(teb) +
+                                 kLastNtStatusOffset) = status;
+  }
+
+  static NTSTATUS GetLastNtStatus() {
+    auto const* teb = ::NtCurrentTeb();
+    return *reinterpret_cast<NTSTATUS const*>(
+        reinterpret_cast<char const*>(teb) + kLastNtStatusOffset);
+  }
+
+ public:
+  // Restore (or just set) the error state of the current thread.
+  static void Apply(WinErrorState const& state) {
+    SetLastNtStatus(state.ntStatus);
+    ::SetLastError(state.error);
+  }
+
+  // Clear the error-state of the current thread.
+  static void Clear() { Apply({.error = 0, .ntStatus = 0}); }
+
+  // Get the error-state of the current thread.
+  static WinErrorState Get() {
+    return WinErrorState{
+        .error = ::GetLastError(),
+        .ntStatus = GetLastNtStatus(),
+    };
+  }
+
+  bool operator==(WinErrorState const& that) const {
+    return this->error == that.error && this->ntStatus == that.ntStatus;
+  }
+
+  bool operator!=(WinErrorState const& that) const { return !operator==(that); }
+};
+
+// Struct containing information about the user atom table. (See
+// DiagnoseUserAtomTable(), below.)
+struct AtomTableInformation {
+  // Number of atoms in use. (Exactly 0x4000 == 16384, if all are.)
+  UINT in_use = 0;
+  // Number of atoms confirmed not in use.
+  UINT free = 0;
+  // Number of atoms which gave errors when checked.
+  UINT errors = 0;
+
+  // Last atom which gave an unexpected error...
+  UINT lastErrorAtom = ~0u;
+  // ... and the error it gave.
+  WinErrorState lastErrorState;
+};
+
+// Return a summary of the state of the atom table.
+MOZ_NEVER_INLINE static AtomTableInformation DiagnoseUserAtomTable() {
+  // Restore error state on exit, for the sake of automated minidump analyses.
+  auto const _restoreErrState =
+      mozilla::MakeScopeExit([oldErrState = WinErrorState::Get()]() {
+        WinErrorState::Apply(oldErrState);
+      });
+
+  AtomTableInformation retval;
+
+  // Expected error-state on failure-return when the atom is assigned, but not
+  // enough space was provided for the full string.
+  constexpr WinErrorState kBufferTooSmall = {
+      .error = ERROR_INSUFFICIENT_BUFFER,
+      .ntStatus = ((NTSTATUS)0xC0000023),  // == STATUS_BUFFER_TOO_SMALL
+  };
+  // Expected error-state on failure-return when the atom is not assigned.
+  constexpr WinErrorState kInvalidAtom = {
+      .error = ERROR_INVALID_HANDLE,
+      .ntStatus = ((NTSTATUS)STATUS_INVALID_HANDLE),
+  };
+
+  // Iterate over only the dynamic portion of the atom table.
+  for (UINT atom = 0xC000; atom <= 0xFFFF; ++atom) {
+    // The actual atom values are PII. Don't acquire them in their entirety, and
+    // don't keep more information about them than is needed.
+    WCHAR buf[2] = {};
+    // USE OF UNDOCUMENTED BEHAVIOR: The user atom table is shared by message
+    // names, window-class names, and clipboard-format names. Only the last has
+    // a documented getter-mechanism.
+    BOOL const ok = ::GetClipboardFormatNameW(atom, buf, 1);
+    WinErrorState const errState = WinErrorState::Get();
+    if (ok || errState == kBufferTooSmall) {
+      ++retval.in_use;
+    } else if (errState == kInvalidAtom) {
+      ++retval.free;
+    } else {
+      // Unexpected error-state.
+      ++retval.errors;
+      retval.lastErrorAtom = atom;
+      retval.lastErrorState = errState;
+    }
+  }
+
+  return retval;
+}
+
+}  // namespace
+
+#if defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED) && defined(_M_X64)
+MOZ_NEVER_INLINE MOZ_NAKED void EnableTrapFlag() {
+  asm volatile(
+      "pushfq;"
+      "orw $0x100,(%rsp);"
+      "popfq;"
+      "retq;");
+}
+
+MOZ_NEVER_INLINE MOZ_NAKED void DisableTrapFlag() { asm volatile("retq;"); }
+
+#  define SSD_MAX_USER32_STEPS 0x1800
+#  define SSD_MAX_ERROR_STATES 0x200
+struct SingleStepData {
+  uint32_t mUser32StepsLog[SSD_MAX_USER32_STEPS]{};
+  WinErrorState mErrorStatesLog[SSD_MAX_ERROR_STATES];
+  uint16_t mUser32StepsAtErrorState[SSD_MAX_ERROR_STATES]{};
+};
+
+struct SingleStepStaticState {
+  SingleStepData* mData{};
+  uintptr_t mUser32Start{};
+  uintptr_t mUser32End{};
+  uint32_t mUser32Steps{};
+  uint32_t mErrorStates{};
+  WinErrorState mLastRecordedErrorState;
+
+  constexpr void Reset() { *this = SingleStepStaticState{}; }
+};
+
+static SingleStepStaticState sSingleStepStaticState{};
+
+LONG SingleStepExceptionHandler(_EXCEPTION_POINTERS* aExceptionInfo) {
+  auto& state = sSingleStepStaticState;
+  if (state.mData &&
+      aExceptionInfo->ExceptionRecord->ExceptionCode == EXCEPTION_SINGLE_STEP) {
+    auto instructionPointer = aExceptionInfo->ContextRecord->Rip;
+    if (instructionPointer == reinterpret_cast<uintptr_t>(&DisableTrapFlag)) {
+      // Stop handling any exception in this handler
+      state.mData = nullptr;
+    } else {
+      // Record data for the current step, if in user32
+      if (state.mUser32Start <= instructionPointer &&
+          instructionPointer < state.mUser32End) {
+        // We record the instruction pointer
+        if (state.mUser32Steps < SSD_MAX_USER32_STEPS) {
+          state.mData->mUser32StepsLog[state.mUser32Steps] =
+              static_cast<uint32_t>(instructionPointer - state.mUser32Start);
+        }
+
+        // We record changes in the error state
+        auto currentErrorState{WinErrorState::Get()};
+        if (currentErrorState != state.mLastRecordedErrorState) {
+          state.mLastRecordedErrorState = currentErrorState;
+
+          if (state.mErrorStates < SSD_MAX_ERROR_STATES) {
+            state.mData->mErrorStatesLog[state.mErrorStates] =
+                currentErrorState;
+            state.mData->mUser32StepsAtErrorState[state.mErrorStates] =
+                state.mUser32Steps;
+          }
+
+          ++state.mErrorStates;
+        }
+
+        ++state.mUser32Steps;
+      }
+
+      // Continue single-stepping
+      aExceptionInfo->ContextRecord->EFlags |= 0x100;
+    }
+    return EXCEPTION_CONTINUE_EXECUTION;
+  }
+  return EXCEPTION_CONTINUE_SEARCH;
+}
+
+enum CSSD_RESULT {
+  CSSD_SUCCESS = 0,
+  CSSD_ERROR_DEBUGGER_PRESENT = 1,
+  CSSD_ERROR_GET_MODULE_HANDLE = 2,
+  CSSD_ERROR_PARSING_USER32 = 3,
+  CSSD_ERROR_ADD_VECTORED_EXCEPTION_HANDLER = 4,
+};
+
+template <typename CallbackToRun, typename PostCollectionCallback>
+[[clang::optnone]] MOZ_NEVER_INLINE CSSD_RESULT
+CollectSingleStepData(CallbackToRun aCallbackToRun,
+                      PostCollectionCallback aPostCollectionCallback) {
+  if (::IsDebuggerPresent()) {
+    return CSSD_ERROR_DEBUGGER_PRESENT;
+  }
+
+  MOZ_DIAGNOSTIC_ASSERT(!sSingleStepStaticState.mData,
+                        "Single-stepping is already active");
+  HANDLE user32 = ::GetModuleHandleW(L"user32.dll");
+  if (!user32) {
+    return CSSD_ERROR_GET_MODULE_HANDLE;
+  }
+
+  nt::PEHeaders user32Headers{user32};
+  auto bounds = user32Headers.GetBounds();
+  if (bounds.isNothing()) {
+    return CSSD_ERROR_PARSING_USER32;
+  }
+
+  SingleStepData singleStepData{};
+
+  sSingleStepStaticState.Reset();
+  sSingleStepStaticState.mUser32Start =
+      reinterpret_cast<uintptr_t>(bounds.ref().begin().get());
+  sSingleStepStaticState.mUser32End =
+      reinterpret_cast<uintptr_t>(bounds.ref().end().get());
+  sSingleStepStaticState.mData = &singleStepData;
+  auto veh = ::AddVectoredExceptionHandler(TRUE, SingleStepExceptionHandler);
+  if (!veh) {
+    sSingleStepStaticState.mData = nullptr;
+    return CSSD_ERROR_ADD_VECTORED_EXCEPTION_HANDLER;
+  }
+
+  EnableTrapFlag();
+  aCallbackToRun();
+  DisableTrapFlag();
+  ::RemoveVectoredExceptionHandler(veh);
+  sSingleStepStaticState.mData = nullptr;
+
+  aPostCollectionCallback();
+
+  return CSSD_SUCCESS;
+}
+#endif  // MOZ_DIAGNOSTIC_ASSERT_ENABLED && _M_X64
+
+// Collect data for bug 1571516. We don't automatically send up `GetLastError`
+// or `GetLastNtStatus` data for beta/release builds, so extract the relevant
+// error values and store them on the stack, where they can be viewed in
+// minidumps -- in fact, do so after each individual API call. This takes the
+// form of various local variables whose initial character is an underscore,
+// most of which are also marked [[maybe_unused]].
+//
+// We tag this function `[[clang::optnone]]` to prevent the compiler from
+// eliding those values as _actually_ unused, as well as to generally simplify
+// the haruspex's task once the minidumps are in. (As this function should be
+// called at most once per process, the minor performance hit is not a concern.)
+//
+[[clang::optnone]] MOZ_NEVER_INLINE nsresult nsAppShell::InitHiddenWindow() {
+  // note the incoming error-state; this may be relevant to errors we get later
+  auto _initialErr [[maybe_unused]] = WinErrorState::Get();
+  // reset the error-state, to avoid ambiguity below
+  WinErrorState::Clear();
+
+  // Diagnostic variable. Only collected in the event of a failure in one of the
+  // functions that attempts to register an atom.
+  AtomTableInformation _atomTableInfo [[maybe_unused]];
+
+  // Attempt to register the window message. On failure, retain the initial
+  // value of `sAppShellGeckoMsgId`.
+  auto const _msgId = ::RegisterWindowMessageW(kAppShellGeckoEventId);
+  if (_msgId) {
+    sAppShellGeckoMsgId = _msgId;
+  }
+  auto const _sAppShellGeckoMsgId [[maybe_unused]] = sAppShellGeckoMsgId;
+  auto const _rwmErr [[maybe_unused]] = WinErrorState::Get();
+  if (!_msgId) _atomTableInfo = DiagnoseUserAtomTable();
+  NS_ASSERTION(sAppShellGeckoMsgId,
+               "Could not register hidden window event message!");
+
+  mLastNativeEventScheduled = TimeStamp::NowLoRes();
+
+  WNDCLASSW wc;
+  HINSTANCE const module = GetModuleHandle(nullptr);
+
+  constexpr const wchar_t* kWindowClass = L"nsAppShell:EventWindowClass";
+  // (Undocumented behavior note: on success, this will specifically be the
+  // window-class atom. We don't rely on this.)
+  BOOL const _gciwRet = ::GetClassInfoW(module, kWindowClass, &wc);
+  auto const _gciwErr [[maybe_unused]] = WinErrorState::Get();
+  WinErrorState::Clear();
+
+  WinErrorState _rcErr [[maybe_unused]];
+  if (!_gciwRet) {
+    wc.style = 0;
+    wc.lpfnWndProc = EventWindowProc;
+    wc.cbClsExtra = 0;
+    wc.cbWndExtra = 0;
+    wc.hInstance = module;
+    wc.hIcon = nullptr;
+    wc.hCursor = nullptr;
+    wc.hbrBackground = (HBRUSH) nullptr;
+    wc.lpszMenuName = (LPCWSTR) nullptr;
+    wc.lpszClassName = kWindowClass;
+
+    ATOM _windowClassAtom = ::RegisterClassW(&wc);
+    _rcErr = WinErrorState::Get();
+
+    if (!_windowClassAtom) _atomTableInfo = DiagnoseUserAtomTable();
+
+#if defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED) && defined(_M_X64)
+    if (!_windowClassAtom) {
+      // Retry with single-step data collection
+      auto cssdResult = CollectSingleStepData(
+          [&wc, &_windowClassAtom]() {
+            _windowClassAtom = ::RegisterClassW(&wc);
+          },
+          [&_windowClassAtom]() {
+            // Crashing here gives access to the single step data on stack
+            MOZ_DIAGNOSTIC_ASSERT(
+                _windowClassAtom,
+                "RegisterClassW for EventWindowClass failed twice");
+          });
+      auto const _cssdErr [[maybe_unused]] = WinErrorState::Get();
+      MOZ_DIAGNOSTIC_ASSERT(
+          cssdResult == CSSD_SUCCESS,
+          "Failed to collect single step data for RegisterClassW");
+      // If we reach this point then somehow the single-stepped call succeeded
+      // and we can proceed
+    }
+#endif  // MOZ_DIAGNOSTIC_ASSERT_ENABLED && _M_X64
+
+    MOZ_DIAGNOSTIC_ASSERT(_windowClassAtom,
+                          "RegisterClassW for EventWindowClass failed");
+    WinErrorState::Clear();
+  }
+
+  mEventWnd = CreateWindowW(kWindowClass, L"nsAppShell:EventWindow", 0, 0, 0,
+                            10, 10, HWND_MESSAGE, nullptr, module, nullptr);
+  auto const _cwErr [[maybe_unused]] = WinErrorState::Get();
+
+#if defined(MOZ_DIAGNOSTIC_ASSERT_ENABLED) && defined(_M_X64)
+  if (!mEventWnd) {
+    // Retry with single-step data collection
+    HWND eventWnd{};
+    auto cssdResult = CollectSingleStepData(
+        [module, &eventWnd]() {
+          eventWnd =
+              CreateWindowW(kWindowClass, L"nsAppShell:EventWindow", 0, 0, 0,
+                            10, 10, HWND_MESSAGE, nullptr, module, nullptr);
+        },
+        [&eventWnd]() {
+          // Crashing here gives access to the single step data on stack
+          MOZ_DIAGNOSTIC_ASSERT(eventWnd,
+                                "CreateWindowW for EventWindow failed twice");
+        });
+    auto const _cssdErr [[maybe_unused]] = WinErrorState::Get();
+    MOZ_DIAGNOSTIC_ASSERT(
+        cssdResult == CSSD_SUCCESS,
+        "Failed to collect single step data for CreateWindowW");
+    // If we reach this point then somehow the single-stepped call succeeded and
+    // we can proceed
+    mEventWnd = eventWnd;
+  }
+#endif  // MOZ_DIAGNOSTIC_ASSERT_ENABLED && _M_X64
+
+  MOZ_DIAGNOSTIC_ASSERT(mEventWnd, "CreateWindowW for EventWindow failed");
+  NS_ENSURE_STATE(mEventWnd);
+
+  return NS_OK;
+}
+
+nsresult nsAppShell::Init() {
+  LSPAnnotate();
+
+  hal::Init();
+
+  if (XRE_IsParentProcess()) {
+    sTaskbarButtonCreatedMsg = ::RegisterWindowMessageW(kTaskbarButtonEventId);
+    NS_ASSERTION(sTaskbarButtonCreatedMsg,
+                 "Could not register taskbar button creation message");
+  }
+
+  // The hidden message window is used for interrupting the processing of native
+  // events, so that we can process gecko events. Therefore, we only need it if
+  // we are processing native events. Disabling this is required for win32k
+  // syscall lockdown.
+  if (XRE_UseNativeEventProcessing()) {
+    if (nsresult rv = this->InitHiddenWindow(); NS_FAILED(rv)) {
+      return rv;
+    }
+  } else if (XRE_IsContentProcess() && !IsWin32kLockedDown()) {
+    // We're not generally processing native events, but still using GDI and we
+    // still have some internal windows, e.g. from calling CoInitializeEx.
+    // So we use a class that will do a single event pump where previously we
+    // might have processed multiple events to make sure any occasional messages
+    // to these windows are processed. This also allows any internal Windows
+    // messages to be processed to ensure the GDI data remains fresh.
+    nsCOMPtr<nsIThreadInternal> threadInt =
+        do_QueryInterface(NS_GetCurrentThread());
+    if (threadInt) {
+      threadInt->SetObserver(new SingleNativeEventPump());
+    }
+  }
+
+  if (XRE_IsParentProcess()) {
+    ScreenManager& screenManager = ScreenManager::GetSingleton();
+    if (gfxPlatform::IsHeadless()) {
+      screenManager.SetHelper(mozilla::MakeUnique<HeadlessScreenHelper>());
+    } else {
+      screenManager.SetHelper(mozilla::MakeUnique<ScreenHelperWin>());
+      ScreenHelperWin::RefreshScreens();
+    }
+
+    nsCOMPtr<nsIObserverService> obsServ(
+        mozilla::services::GetObserverService());
+
+    obsServ->AddObserver(this, "sessionstore-restoring-on-startup", false);
+    obsServ->AddObserver(this, "sessionstore-windows-restored", false);
+  }
+
+  if (!WinUtils::GetTimezoneName(mTimezoneName)) {
+    NS_WARNING("Unable to get system timezone name, timezone may be invalid\n");
+  }
+
+  return nsBaseAppShell::Init();
+}
+
+NS_IMETHODIMP
+nsAppShell::Run(void) {
+  bool wantAudio = true;
+  if (XRE_IsParentProcess()) {
+#ifdef MOZ_BACKGROUNDTASKS
+    if (BackgroundTasks::IsBackgroundTaskMode()) {
+      wantAudio = false;
+    }
+#endif
+    if (MOZ_LIKELY(wantAudio)) {
+      mozilla::widget::StartAudioSession();
+    }
+
+    // Add an observer that disables the screen saver when requested by Gecko.
+    // For example when we're playing video in the foreground tab. Whole firefox
+    // only needs one wakelock instance, so we would only create one listener in
+    // chrome process to prevent requesting unnecessary wakelock.
+    AddScreenWakeLockListener();
+  }
+
+  nsresult rv = nsBaseAppShell::Run();
+
+  if (XRE_IsParentProcess()) {
+    RemoveScreenWakeLockListener();
+
+    if (MOZ_LIKELY(wantAudio)) {
+      mozilla::widget::StopAudioSession();
+    }
+  }
+
+  return rv;
+}
+
+void nsAppShell::DoProcessMoreGeckoEvents() {
+  // Called by nsBaseAppShell's NativeEventCallback() after it has finished
+  // processing pending gecko events and there are still gecko events pending
+  // for the thread. (This can happen if NS_ProcessPendingEvents reached it's
+  // starvation timeout limit.) The default behavior in nsBaseAppShell is to
+  // call ScheduleNativeEventCallback to post a follow up native event callback
+  // message. This triggers an additional call to NativeEventCallback for more
+  // gecko event processing.
+
+  // There's a deadlock risk here with certain internal Windows modal loops. In
+  // our dispatch code, we prioritize messages so that input is handled first.
+  // However Windows modal dispatch loops often prioritize posted messages. If
+  // we find ourselves in a tight gecko timer loop where NS_ProcessPendingEvents
+  // takes longer than the timer duration, NS_HasPendingEvents(thread) will
+  // always be true. ScheduleNativeEventCallback will be called on every
+  // NativeEventCallback callback, and in a Windows modal dispatch loop, the
+  // callback message will be processed first -> input gets starved, dead lock.
+
+  // To avoid, don't post native callback messages from NativeEventCallback
+  // when we're in a modal loop. This gets us back into the Windows modal
+  // dispatch loop dispatching input messages. Once we drop out of the modal
+  // loop, we use mNativeCallbackPending to fire off a final NativeEventCallback
+  // if we need it, which insures NS_ProcessPendingEvents gets called and all
+  // gecko events get processed.
+  if (mEventloopNestingLevel < 2) {
+    OnDispatchedEvent();
+    mNativeCallbackPending = false;
+  } else {
+    mNativeCallbackPending = true;
+  }
+}
+
+void nsAppShell::ScheduleNativeEventCallback() {
+  MOZ_ASSERT(mEventWnd,
+             "We should have created mEventWnd in Init, if this is called.");
+
+  // Post a message to the hidden message window
+  ++sOutstandingNativeEventCallbacks;
+  {
+    MutexAutoLock lock(mLastNativeEventScheduledMutex);
+    // Time stamp this event so we can detect cases where the event gets
+    // dropping in sub classes / modal loops we do not control.
+    mLastNativeEventScheduled = TimeStamp::NowLoRes();
+  }
+  ::PostMessage(mEventWnd, sAppShellGeckoMsgId, 0,
+                reinterpret_cast<LPARAM>(this));
+}
+
+bool nsAppShell::ProcessNextNativeEvent(bool mayWait) {
+  // Notify ipc we are spinning a (possibly nested) gecko event loop.
+  mozilla::ipc::MessageChannel::NotifyGeckoEventDispatch();
+
+  bool gotMessage = false;
+
+  do {
+    MSG msg;
+
+    // For avoiding deadlock between our process and plugin process by
+    // mouse wheel messages, we're handling actually when we receive one of
+    // following internal messages which is posted by native mouse wheel
+    // message handler. Any other events, especially native modifier key
+    // events, should not be handled between native message and posted
+    // internal message because it may make different modifier key state or
+    // mouse cursor position between them.
+    if (mozilla::widget::MouseScrollHandler::IsWaitingInternalMessage()) {
+      gotMessage = WinUtils::PeekMessage(&msg, nullptr, MOZ_WM_MOUSEWHEEL_FIRST,
+                                         MOZ_WM_MOUSEWHEEL_LAST, PM_REMOVE);
+      NS_ASSERTION(gotMessage,
+                   "waiting internal wheel message, but it has not come");
+    }
+
+    if (!gotMessage) {
+      gotMessage = WinUtils::PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE);
+    }
+
+    if (gotMessage) {
+      if (msg.message == WM_QUIT) {
+        ::PostQuitMessage(msg.wParam);
+        Exit();
+      } else {
+        // If we had UI activity we would be processing it now so we know we
+        // have either kUIActivity or kActivityNoUIAVail.
+        mozilla::BackgroundHangMonitor().NotifyActivity();
+
+        if (msg.message >= WM_KEYFIRST && msg.message <= WM_KEYLAST &&
+            IMEHandler::ProcessRawKeyMessage(msg)) {
+          continue;  // the message is consumed.
+        }
+
+#if defined(_X86_)
+        // Store Printer dialog messages for reposting on x86, because on x86
+        // Windows 7 they are not processed by a window procedure, but are
+        // explicitly waited for in the winspool.drv code that will be further
+        // up the stack (winspool!WaitForCompletionMessage). These are
+        // undocumented Windows Message identifiers found in winspool.drv.
+        if (msg.message == 0x5b7a || msg.message == 0x5b7f ||
+            msg.message == 0x5b80 || msg.message == 0x5b81) {
+          mMsgsToRepost.push_back(msg);
+          continue;
+        }
+#endif
+
+        // Windows documentation suggets that WM_SETTINGSCHANGE is the message
+        // to watch for timezone changes, but experimentation showed that it
+        // doesn't fire on changing the timezone, but that WM_TIMECHANGE does,
+        // even if there's no immediate effect on the clock (e.g., changing
+        // from Pacific Daylight at UTC-7 to Arizona at UTC-7).
+        if (msg.message == WM_TIMECHANGE) {
+          // The message may not give us sufficient information to determine
+          // if the timezone changed, so keep track of it ourselves.
+          wchar_t systemTimezone[128];
+          bool getSystemTimeSucceeded =
+              WinUtils::GetTimezoneName(systemTimezone);
+          if (getSystemTimeSucceeded && wcscmp(systemTimezone, mTimezoneName)) {
+            nsBaseAppShell::OnSystemTimezoneChange();
+
+            wcscpy_s(mTimezoneName, 128, systemTimezone);
+          }
+        }
+
+        ::TranslateMessage(&msg);
+        ::DispatchMessageW(&msg);
+      }
+    } else if (mayWait) {
+      // Block and wait for any posted application message
+      mozilla::BackgroundHangMonitor().NotifyWait();
+      {
+        AUTO_PROFILER_LABEL("nsAppShell::ProcessNextNativeEvent::Wait", IDLE);
+        WinUtils::WaitForMessage();
+      }
+    }
+  } while (!gotMessage && mayWait);
+
+  // See DoProcessNextNativeEvent, mEventloopNestingLevel will be
+  // one when a modal loop unwinds.
+  if (mNativeCallbackPending && mEventloopNestingLevel == 1)
+    DoProcessMoreGeckoEvents();
+
+  // Check for starved native callbacks. If we haven't processed one
+  // of these events in NATIVE_EVENT_STARVATION_LIMIT, fire one off.
+  static const mozilla::TimeDuration nativeEventStarvationLimit =
+      mozilla::TimeDuration::FromSeconds(NATIVE_EVENT_STARVATION_LIMIT);
+
+  TimeDuration timeSinceLastNativeEventScheduled;
+  {
+    MutexAutoLock lock(mLastNativeEventScheduledMutex);
+    timeSinceLastNativeEventScheduled =
+        TimeStamp::NowLoRes() - mLastNativeEventScheduled;
+  }
+  if (timeSinceLastNativeEventScheduled > nativeEventStarvationLimit) {
+    ScheduleNativeEventCallback();
+  }
+
+  return gotMessage;
+}
+
+nsresult nsAppShell::AfterProcessNextEvent(nsIThreadInternal* /* unused */,
+                                           bool /* unused */) {
+  if (!mMsgsToRepost.empty()) {
+    for (MSG msg : mMsgsToRepost) {
+      ::PostMessageW(msg.hwnd, msg.message, msg.wParam, msg.lParam);
+    }
+    mMsgsToRepost.clear();
+  }
+  return NS_OK;
+}
diff --git a/widget/windows/nsAppShell.h b/widget/windows/nsAppShell.h
new file mode 100644
index 0000000000..20ea65e834
--- /dev/null
+++ b/widget/windows/nsAppShell.h
@@ -0,0 +1,64 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsAppShell_h__
+#define nsAppShell_h__
+
+#include "nsBaseAppShell.h"
+#include <windows.h>
+#include <vector>
+#include "mozilla/TimeStamp.h"
+#include "mozilla/Mutex.h"
+
+// The maximum time we allow before forcing a native event callback.
+// In seconds.
+#define NATIVE_EVENT_STARVATION_LIMIT 1
+
+/**
+ * Native Win32 Application shell wrapper
+ */
+class nsAppShell final : public nsBaseAppShell {
+ public:
+  nsAppShell()
+      : mEventWnd(nullptr),
+        mNativeCallbackPending(false),
+        mLastNativeEventScheduledMutex(
+            "nsAppShell::mLastNativeEventScheduledMutex") {}
+  typedef mozilla::TimeStamp TimeStamp;
+  typedef mozilla::Mutex Mutex;
+
+  nsresult Init();
+  void DoProcessMoreGeckoEvents();
+
+  static UINT GetTaskbarButtonCreatedMessage();
+
+  NS_IMETHOD AfterProcessNextEvent(nsIThreadInternal* thread,
+                                   bool eventWasProcessed) final;
+
+ protected:
+  NS_IMETHOD Run() override;
+  NS_IMETHOD Observe(nsISupports* aSubject, const char* aTopic,
+                     const char16_t* aData) override;
+
+  virtual void ScheduleNativeEventCallback();
+  virtual bool ProcessNextNativeEvent(bool mayWait);
+  virtual ~nsAppShell();
+
+  static LRESULT CALLBACK EventWindowProc(HWND, UINT, WPARAM, LPARAM);
+
+ protected:
+  nsresult InitHiddenWindow();
+  HWND mEventWnd;
+  bool mNativeCallbackPending;
+
+  Mutex mLastNativeEventScheduledMutex MOZ_UNANNOTATED;
+  TimeStamp mLastNativeEventScheduled;
+  std::vector<MSG> mMsgsToRepost;
+
+ private:
+  wchar_t mTimezoneName[128];
+};
+
+#endif  // nsAppShell_h__
diff --git a/widget/windows/nsBidiKeyboard.cpp b/widget/windows/nsBidiKeyboard.cpp
new file mode 100644
index 0000000000..87d81d458e
--- /dev/null
+++ b/widget/windows/nsBidiKeyboard.cpp
@@ -0,0 +1,169 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <stdio.h>
+#include "nsBidiKeyboard.h"
+#include "WidgetUtils.h"
+#include "nsIWidget.h"
+#include <tchar.h>
+
+NS_IMPL_ISUPPORTS(nsBidiKeyboard, nsIBidiKeyboard)
+
+nsBidiKeyboard::nsBidiKeyboard() : nsIBidiKeyboard() { Reset(); }
+
+nsBidiKeyboard::~nsBidiKeyboard() {}
+
+NS_IMETHODIMP nsBidiKeyboard::Reset() {
+  mInitialized = false;
+  mHaveBidiKeyboards = false;
+  mLTRKeyboard[0] = '\0';
+  mRTLKeyboard[0] = '\0';
+  mCurrentLocaleName[0] = '\0';
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBidiKeyboard::IsLangRTL(bool* aIsRTL) {
+  *aIsRTL = false;
+
+  nsresult result = SetupBidiKeyboards();
+  if (NS_FAILED(result)) return result;
+
+  HKL currentLocale;
+
+  currentLocale = ::GetKeyboardLayout(0);
+  *aIsRTL = IsRTLLanguage(currentLocale);
+
+  if (!::GetKeyboardLayoutNameW(mCurrentLocaleName)) return NS_ERROR_FAILURE;
+
+  NS_ASSERTION(*mCurrentLocaleName,
+               "GetKeyboardLayoutName return string length == 0");
+  NS_ASSERTION((wcslen(mCurrentLocaleName) < KL_NAMELENGTH),
+               "GetKeyboardLayoutName return string length >= KL_NAMELENGTH");
+
+  // The language set by the user overrides the default language for that
+  // direction
+  if (*aIsRTL) {
+    wcsncpy(mRTLKeyboard, mCurrentLocaleName, KL_NAMELENGTH);
+    mRTLKeyboard[KL_NAMELENGTH - 1] = '\0';  // null terminate
+  } else {
+    wcsncpy(mLTRKeyboard, mCurrentLocaleName, KL_NAMELENGTH);
+    mLTRKeyboard[KL_NAMELENGTH - 1] = '\0';  // null terminate
+  }
+
+  NS_ASSERTION((wcslen(mRTLKeyboard) < KL_NAMELENGTH),
+               "mLTRKeyboard has string length >= KL_NAMELENGTH");
+  NS_ASSERTION((wcslen(mLTRKeyboard) < KL_NAMELENGTH),
+               "mRTLKeyboard has string length >= KL_NAMELENGTH");
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBidiKeyboard::GetHaveBidiKeyboards(bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+
+  nsresult result = SetupBidiKeyboards();
+  if (NS_FAILED(result)) return result;
+
+  *aResult = mHaveBidiKeyboards;
+  return NS_OK;
+}
+
+// Get the list of keyboard layouts available in the system
+// Set mLTRKeyboard to the first LTR keyboard in the list and mRTLKeyboard to
+// the first RTL keyboard in the list These defaults will be used unless the
+// user explicitly sets something else.
+nsresult nsBidiKeyboard::SetupBidiKeyboards() {
+  if (mInitialized) return mHaveBidiKeyboards ? NS_OK : NS_ERROR_FAILURE;
+
+  int keyboards;
+  HKL far* buf;
+  HKL locale;
+  wchar_t localeName[KL_NAMELENGTH];
+  bool isLTRKeyboardSet = false;
+  bool isRTLKeyboardSet = false;
+
+  // GetKeyboardLayoutList with 0 as first parameter returns the number of
+  // keyboard layouts available
+  keyboards = ::GetKeyboardLayoutList(0, nullptr);
+  if (!keyboards) return NS_ERROR_FAILURE;
+
+  // allocate a buffer to hold the list
+  buf = (HKL far*)malloc(keyboards * sizeof(HKL));
+  if (!buf) return NS_ERROR_OUT_OF_MEMORY;
+
+  // Call again to fill the buffer
+  if (::GetKeyboardLayoutList(keyboards, buf) != keyboards) {
+    free(buf);
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  // Go through the list and pick a default LTR and RTL keyboard layout
+  while (keyboards--) {
+    locale = buf[keyboards];
+    if (IsRTLLanguage(locale)) {
+      _snwprintf(mRTLKeyboard, KL_NAMELENGTH, L"%.*x", KL_NAMELENGTH - 1,
+                 LANGIDFROMLCID((DWORD_PTR)locale));
+      isRTLKeyboardSet = true;
+    } else {
+      _snwprintf(mLTRKeyboard, KL_NAMELENGTH, L"%.*x", KL_NAMELENGTH - 1,
+                 LANGIDFROMLCID((DWORD_PTR)locale));
+      isLTRKeyboardSet = true;
+    }
+  }
+  free(buf);
+  mInitialized = true;
+
+  // If there is not at least one keyboard of each directionality, Bidi
+  // keyboard functionality will be disabled.
+  mHaveBidiKeyboards = (isRTLKeyboardSet && isLTRKeyboardSet);
+  if (!mHaveBidiKeyboards) return NS_ERROR_FAILURE;
+
+  // Get the current keyboard layout and use it for either mRTLKeyboard or
+  // mLTRKeyboard as appropriate. If the user has many keyboard layouts
+  // installed this prevents us from arbitrarily resetting the current
+  // layout (bug 80274)
+  locale = ::GetKeyboardLayout(0);
+  if (!::GetKeyboardLayoutNameW(localeName)) return NS_ERROR_FAILURE;
+
+  NS_ASSERTION(*localeName, "GetKeyboardLayoutName return string length == 0");
+  NS_ASSERTION((wcslen(localeName) < KL_NAMELENGTH),
+               "GetKeyboardLayout return string length >= KL_NAMELENGTH");
+
+  if (IsRTLLanguage(locale)) {
+    wcsncpy(mRTLKeyboard, localeName, KL_NAMELENGTH);
+    mRTLKeyboard[KL_NAMELENGTH - 1] = '\0';  // null terminate
+  } else {
+    wcsncpy(mLTRKeyboard, localeName, KL_NAMELENGTH);
+    mLTRKeyboard[KL_NAMELENGTH - 1] = '\0';  // null terminate
+  }
+
+  NS_ASSERTION(*mRTLKeyboard, "mLTRKeyboard has string length == 0");
+  NS_ASSERTION(*mLTRKeyboard, "mLTRKeyboard has string length == 0");
+
+  return NS_OK;
+}
+
+// Test whether the language represented by this locale identifier is a
+//  right-to-left language, using bit 123 of the Unicode subset bitfield in
+//  the LOCALESIGNATURE
+// See
+// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/intl/unicode_63ub.asp
+bool nsBidiKeyboard::IsRTLLanguage(HKL aLocale) {
+  LOCALESIGNATURE localesig;
+  return (::GetLocaleInfoW(PRIMARYLANGID((DWORD_PTR)aLocale),
+                           LOCALE_FONTSIGNATURE, (LPWSTR)&localesig,
+                           (sizeof(localesig) / sizeof(WCHAR))) &&
+          (localesig.lsUsb[3] & 0x08000000));
+}
+
+// static
+void nsBidiKeyboard::OnLayoutChange() {
+  mozilla::widget::WidgetUtils::SendBidiKeyboardInfoToContent();
+}
+
+// static
+already_AddRefed<nsIBidiKeyboard> nsIWidget::CreateBidiKeyboardInner() {
+  return do_AddRef(new nsBidiKeyboard());
+}
diff --git a/widget/windows/nsBidiKeyboard.h b/widget/windows/nsBidiKeyboard.h
new file mode 100644
index 0000000000..584d4d2dee
--- /dev/null
+++ b/widget/windows/nsBidiKeyboard.h
@@ -0,0 +1,34 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsBidiKeyboard
+#define __nsBidiKeyboard
+#include "nsIBidiKeyboard.h"
+#include <windows.h>
+
+class nsBidiKeyboard : public nsIBidiKeyboard {
+  virtual ~nsBidiKeyboard();
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIBIDIKEYBOARD
+
+  nsBidiKeyboard();
+
+  static void OnLayoutChange();
+
+ protected:
+  nsresult SetupBidiKeyboards();
+  bool IsRTLLanguage(HKL aLocale);
+
+  bool mInitialized;
+  bool mHaveBidiKeyboards;
+  wchar_t mLTRKeyboard[KL_NAMELENGTH];
+  wchar_t mRTLKeyboard[KL_NAMELENGTH];
+  wchar_t mCurrentLocaleName[KL_NAMELENGTH];
+};
+
+#endif  // __nsBidiKeyboard
diff --git a/widget/windows/nsClipboard.cpp b/widget/windows/nsClipboard.cpp
new file mode 100644
index 0000000000..8783affd1e
--- /dev/null
+++ b/widget/windows/nsClipboard.cpp
@@ -0,0 +1,1472 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsClipboard.h"
+
+#include <shlobj.h>
+#include <intshcut.h>
+
+// shellapi.h is needed to build with WIN32_LEAN_AND_MEAN
+#include <shellapi.h>
+
+#include <functional>
+#include <thread>
+#include <chrono>
+
+#ifdef ACCESSIBILITY
+#  include "mozilla/a11y/Compatibility.h"
+#endif
+#include "mozilla/Logging.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPrefs_clipboard.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/WindowsVersion.h"
+#include "SpecialSystemDirectory.h"
+
+#include "nsArrayUtils.h"
+#include "nsCOMPtr.h"
+#include "nsComponentManagerUtils.h"
+#include "nsDataObj.h"
+#include "nsString.h"
+#include "nsNativeCharsetUtils.h"
+#include "nsIInputStream.h"
+#include "nsITransferable.h"
+#include "nsXPCOM.h"
+#include "nsReadableUtils.h"
+#include "nsUnicharUtils.h"
+#include "nsPrimitiveHelpers.h"
+#include "nsIWidget.h"
+#include "nsWidgetsCID.h"
+#include "nsCRT.h"
+#include "nsNetUtil.h"
+#include "nsIFileProtocolHandler.h"
+#include "nsEscape.h"
+#include "nsIObserverService.h"
+#include "nsMimeTypes.h"
+#include "imgITools.h"
+#include "imgIContainer.h"
+#include "WinUtils.h"
+
+/* static */
+UINT nsClipboard::GetClipboardFileDescriptorFormatA() {
+  static UINT format = ::RegisterClipboardFormatW(CFSTR_FILEDESCRIPTORA);
+  MOZ_ASSERT(format);
+  return format;
+}
+
+/* static */
+UINT nsClipboard::GetClipboardFileDescriptorFormatW() {
+  static UINT format = ::RegisterClipboardFormatW(CFSTR_FILEDESCRIPTORW);
+  MOZ_ASSERT(format);
+  return format;
+}
+
+/* static */
+UINT nsClipboard::GetHtmlClipboardFormat() {
+  static UINT format = ::RegisterClipboardFormatW(L"HTML Format");
+  return format;
+}
+
+/* static */
+UINT nsClipboard::GetCustomClipboardFormat() {
+  static UINT format =
+      ::RegisterClipboardFormatW(L"application/x-moz-custom-clipdata");
+  return format;
+}
+
+//-------------------------------------------------------------------------
+//
+// nsClipboard constructor
+//
+//-------------------------------------------------------------------------
+nsClipboard::nsClipboard()
+    : nsBaseClipboard(mozilla::dom::ClipboardCapabilities(
+          false /* supportsSelectionClipboard */,
+          false /* supportsFindClipboard */,
+          false /* supportsSelectionCache */)) {
+  mWindow = nullptr;
+
+  // Register for a shutdown notification so that we can flush data
+  // to the OS clipboard.
+  nsCOMPtr<nsIObserverService> observerService =
+      do_GetService("@mozilla.org/observer-service;1");
+  if (observerService) {
+    observerService->AddObserver(this, NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID,
+                                 false);
+  }
+}
+
+//-------------------------------------------------------------------------
+// nsClipboard destructor
+//-------------------------------------------------------------------------
+nsClipboard::~nsClipboard() {}
+
+NS_IMPL_ISUPPORTS_INHERITED(nsClipboard, nsBaseClipboard, nsIObserver)
+
+NS_IMETHODIMP
+nsClipboard::Observe(nsISupports* aSubject, const char* aTopic,
+                     const char16_t* aData) {
+  // This will be called on shutdown.
+  ::OleFlushClipboard();
+  ::CloseClipboard();
+
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+UINT nsClipboard::GetFormat(const char* aMimeStr, bool aMapHTMLMime) {
+  UINT format;
+
+  if (strcmp(aMimeStr, kTextMime) == 0) {
+    format = CF_UNICODETEXT;
+  } else if (strcmp(aMimeStr, kRTFMime) == 0) {
+    format = ::RegisterClipboardFormat(L"Rich Text Format");
+  } else if (strcmp(aMimeStr, kJPEGImageMime) == 0 ||
+             strcmp(aMimeStr, kJPGImageMime) == 0 ||
+             strcmp(aMimeStr, kPNGImageMime) == 0) {
+    format = CF_DIBV5;
+  } else if (strcmp(aMimeStr, kFileMime) == 0 ||
+             strcmp(aMimeStr, kFilePromiseMime) == 0) {
+    format = CF_HDROP;
+  } else if ((strcmp(aMimeStr, kNativeHTMLMime) == 0) ||
+             (aMapHTMLMime && strcmp(aMimeStr, kHTMLMime) == 0)) {
+    format = GetHtmlClipboardFormat();
+  } else if (strcmp(aMimeStr, kCustomTypesMime) == 0) {
+    format = GetCustomClipboardFormat();
+  } else {
+    format = ::RegisterClipboardFormatW(NS_ConvertASCIItoUTF16(aMimeStr).get());
+  }
+
+  return format;
+}
+
+//-------------------------------------------------------------------------
+// static
+nsresult nsClipboard::CreateNativeDataObject(
+    nsITransferable* aTransferable, IDataObject** aDataObj, nsIURI* aUri,
+    MightNeedToFlush* aMightNeedToFlush) {
+  MOZ_ASSERT(aTransferable);
+  if (!aTransferable) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Create our native DataObject that implements the OLE IDataObject interface
+  RefPtr<nsDataObj> dataObj = new nsDataObj(aUri);
+
+  // Now set it up with all the right data flavors & enums
+  nsresult res =
+      SetupNativeDataObject(aTransferable, dataObj, aMightNeedToFlush);
+  if (NS_SUCCEEDED(res)) {
+    dataObj.forget(aDataObj);
+  }
+  return res;
+}
+
+static nsresult StoreValueInDataObject(nsDataObj* aObj,
+                                       LPCWSTR aClipboardFormat, DWORD value) {
+  HGLOBAL hGlobalMemory = ::GlobalAlloc(GMEM_MOVEABLE, sizeof(DWORD));
+  if (!hGlobalMemory) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  DWORD* pdw = (DWORD*)::GlobalLock(hGlobalMemory);
+  *pdw = value;
+  ::GlobalUnlock(hGlobalMemory);
+
+  STGMEDIUM stg;
+  stg.tymed = TYMED_HGLOBAL;
+  stg.pUnkForRelease = nullptr;
+  stg.hGlobal = hGlobalMemory;
+
+  FORMATETC fe;
+  SET_FORMATETC(fe, ::RegisterClipboardFormat(aClipboardFormat), 0,
+                DVASPECT_CONTENT, -1, TYMED_HGLOBAL)
+  aObj->SetData(&fe, &stg, TRUE);
+
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+nsresult nsClipboard::SetupNativeDataObject(
+    nsITransferable* aTransferable, IDataObject* aDataObj,
+    MightNeedToFlush* aMightNeedToFlush) {
+  MOZ_ASSERT(aTransferable);
+  MOZ_ASSERT(aDataObj);
+  if (!aTransferable || !aDataObj) {
+    return NS_ERROR_FAILURE;
+  }
+
+  auto* dObj = static_cast<nsDataObj*>(aDataObj);
+  if (aMightNeedToFlush) {
+    *aMightNeedToFlush = MightNeedToFlush::No;
+  }
+
+  // Now give the Transferable to the DataObject
+  // for getting the data out of it
+  dObj->SetTransferable(aTransferable);
+
+  // Get the transferable list of data flavors
+  nsTArray<nsCString> flavors;
+  aTransferable->FlavorsTransferableCanExport(flavors);
+
+  // Walk through flavors that contain data and register them
+  // into the DataObj as supported flavors
+  for (uint32_t i = 0; i < flavors.Length(); i++) {
+    nsCString& flavorStr = flavors[i];
+
+    // When putting data onto the clipboard, we want to maintain kHTMLMime
+    // ("text/html") and not map it to CF_HTML here since this will be done
+    // below.
+    UINT format = GetFormat(flavorStr.get(), false);
+
+    // Now tell the native IDataObject about both our mime type and
+    // the native data format
+    FORMATETC fe;
+    SET_FORMATETC(fe, format, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+    dObj->AddDataFlavor(flavorStr.get(), &fe);
+
+    // Do various things internal to the implementation, like map one
+    // flavor to another or add additional flavors based on what's required
+    // for the win32 impl.
+    if (flavorStr.EqualsLiteral(kTextMime)) {
+      // if we find text/plain, also add CF_TEXT, but we can add it for
+      // text/plain as well.
+      FORMATETC textFE;
+      SET_FORMATETC(textFE, CF_TEXT, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+      dObj->AddDataFlavor(kTextMime, &textFE);
+      if (aMightNeedToFlush) {
+        *aMightNeedToFlush = MightNeedToFlush::Yes;
+      }
+    } else if (flavorStr.EqualsLiteral(kHTMLMime)) {
+      // if we find text/html, also advertise win32's html flavor (which we will
+      // convert on our own in nsDataObj::GetText().
+      FORMATETC htmlFE;
+      SET_FORMATETC(htmlFE, GetHtmlClipboardFormat(), 0, DVASPECT_CONTENT, -1,
+                    TYMED_HGLOBAL);
+      dObj->AddDataFlavor(kHTMLMime, &htmlFE);
+    } else if (flavorStr.EqualsLiteral(kURLMime)) {
+      // if we're a url, in addition to also being text, we need to register
+      // the "file" flavors so that the win32 shell knows to create an internet
+      // shortcut when it sees one of these beasts.
+      FORMATETC shortcutFE;
+      SET_FORMATETC(shortcutFE,
+                    ::RegisterClipboardFormat(CFSTR_FILEDESCRIPTORA), 0,
+                    DVASPECT_CONTENT, -1, TYMED_HGLOBAL)
+      dObj->AddDataFlavor(kURLMime, &shortcutFE);
+      SET_FORMATETC(shortcutFE,
+                    ::RegisterClipboardFormat(CFSTR_FILEDESCRIPTORW), 0,
+                    DVASPECT_CONTENT, -1, TYMED_HGLOBAL)
+      dObj->AddDataFlavor(kURLMime, &shortcutFE);
+      SET_FORMATETC(shortcutFE, ::RegisterClipboardFormat(CFSTR_FILECONTENTS),
+                    0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL)
+      dObj->AddDataFlavor(kURLMime, &shortcutFE);
+      SET_FORMATETC(shortcutFE, ::RegisterClipboardFormat(CFSTR_INETURLA), 0,
+                    DVASPECT_CONTENT, -1, TYMED_HGLOBAL)
+      dObj->AddDataFlavor(kURLMime, &shortcutFE);
+      SET_FORMATETC(shortcutFE, ::RegisterClipboardFormat(CFSTR_INETURLW), 0,
+                    DVASPECT_CONTENT, -1, TYMED_HGLOBAL)
+      dObj->AddDataFlavor(kURLMime, &shortcutFE);
+    } else if (flavorStr.EqualsLiteral(kPNGImageMime) ||
+               flavorStr.EqualsLiteral(kJPEGImageMime) ||
+               flavorStr.EqualsLiteral(kJPGImageMime) ||
+               flavorStr.EqualsLiteral(kGIFImageMime) ||
+               flavorStr.EqualsLiteral(kNativeImageMime)) {
+      // if we're an image, register the native bitmap flavor
+      FORMATETC imageFE;
+      // Add DIBv5
+      SET_FORMATETC(imageFE, CF_DIBV5, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL)
+      dObj->AddDataFlavor(flavorStr.get(), &imageFE);
+      // Add DIBv3
+      SET_FORMATETC(imageFE, CF_DIB, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL)
+      dObj->AddDataFlavor(flavorStr.get(), &imageFE);
+    } else if (flavorStr.EqualsLiteral(kFilePromiseMime)) {
+      // if we're a file promise flavor, also register the
+      // CFSTR_PREFERREDDROPEFFECT format.  The data object
+      // returns a value of DROPEFFECTS_MOVE to the drop target
+      // when it asks for the value of this format.  This causes
+      // the file to be moved from the temporary location instead
+      // of being copied.  The right thing to do here is to call
+      // SetData() on the data object and set the value of this format
+      // to DROPEFFECTS_MOVE on this particular data object.  But,
+      // since all the other clipboard formats follow the model of setting
+      // data on the data object only when the drop object calls GetData(),
+      // I am leaving this format's value hard coded in the data object.
+      // We can change this if other consumers of this format get added to this
+      // codebase and they need different values.
+      FORMATETC shortcutFE;
+      SET_FORMATETC(shortcutFE,
+                    ::RegisterClipboardFormat(CFSTR_PREFERREDDROPEFFECT), 0,
+                    DVASPECT_CONTENT, -1, TYMED_HGLOBAL)
+      dObj->AddDataFlavor(kFilePromiseMime, &shortcutFE);
+    }
+  }
+
+  if (!mozilla::StaticPrefs::
+          clipboard_copyPrivateDataToClipboardCloudOrHistory()) {
+    // Let Clipboard know that data is sensitive and must not be copied to
+    // the Cloud Clipboard, Clipboard History and similar.
+    // https://docs.microsoft.com/en-us/windows/win32/dataxchg/clipboard-formats#cloud-clipboard-and-clipboard-history-formats
+    if (aTransferable->GetIsPrivateData()) {
+      nsresult rv =
+          StoreValueInDataObject(dObj, TEXT("CanUploadToCloudClipboard"), 0);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv =
+          StoreValueInDataObject(dObj, TEXT("CanIncludeInClipboardHistory"), 0);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = StoreValueInDataObject(
+          dObj, TEXT("ExcludeClipboardContentFromMonitorProcessing"), 0);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
+  return NS_OK;
+}
+
+// See methods listed at
+// <https://docs.microsoft.com/en-us/windows/win32/api/objidl/nn-objidl-idataobject#methods>.
+static void IDataObjectMethodResultToString(const HRESULT aHres,
+                                            nsACString& aResult) {
+  switch (aHres) {
+    case E_INVALIDARG:
+      aResult = "E_INVALIDARG";
+      break;
+    case E_UNEXPECTED:
+      aResult = "E_UNEXPECTED";
+      break;
+    case E_OUTOFMEMORY:
+      aResult = "E_OUTOFMEMORY";
+      break;
+    case DV_E_LINDEX:
+      aResult = "DV_E_LINDEX";
+      break;
+    case DV_E_FORMATETC:
+      aResult = "DV_E_FORMATETC";
+      break;
+    case DV_E_TYMED:
+      aResult = "DV_E_TYMED";
+      break;
+    case DV_E_DVASPECT:
+      aResult = "DV_E_DVASPECT";
+      break;
+    case OLE_E_NOTRUNNING:
+      aResult = "OLE_E_NOTRUNNING";
+      break;
+    case STG_E_MEDIUMFULL:
+      aResult = "STG_E_MEDIUMFULL";
+      break;
+    case DV_E_CLIPFORMAT:
+      aResult = "DV_E_CLIPFORMAT";
+      break;
+    case S_OK:
+      aResult = "S_OK";
+      break;
+    default:
+      // Explicit template instantiaton, because otherwise the call is
+      // ambiguous.
+      constexpr int kRadix = 16;
+      aResult = IntToCString<int32_t>(aHres, kRadix);
+      break;
+  }
+}
+
+// See
+// <https://docs.microsoft.com/en-us/windows/win32/api/ole2/nf-ole2-olegetclipboard>.
+static void OleGetClipboardResultToString(const HRESULT aHres,
+                                          nsACString& aResult) {
+  switch (aHres) {
+    case S_OK:
+      aResult = "S_OK";
+      break;
+    case CLIPBRD_E_CANT_OPEN:
+      aResult = "CLIPBRD_E_CANT_OPEN";
+      break;
+    case CLIPBRD_E_CANT_CLOSE:
+      aResult = "CLIPBRD_E_CANT_CLOSE";
+      break;
+    default:
+      // Explicit template instantiaton, because otherwise the call is
+      // ambiguous.
+      constexpr int kRadix = 16;
+      aResult = IntToCString<int32_t>(aHres, kRadix);
+      break;
+  }
+}
+
+// See
+// <https://docs.microsoft.com/en-us/windows/win32/api/ole2/nf-ole2-olegetclipboard>.
+static void LogOleGetClipboardResult(const HRESULT aHres) {
+  if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+    nsAutoCString hresString;
+    OleGetClipboardResultToString(aHres, hresString);
+    MOZ_CLIPBOARD_LOG("OleGetClipboard result: %s", hresString.get());
+  }
+}
+
+// See
+// <https://docs.microsoft.com/en-us/windows/win32/api/ole2/nf-ole2-olesetclipboard>.
+static void OleSetClipboardResultToString(HRESULT aHres, nsACString& aResult) {
+  switch (aHres) {
+    case S_OK:
+      aResult = "S_OK";
+      break;
+    case CLIPBRD_E_CANT_OPEN:
+      aResult = "CLIPBRD_E_CANT_OPEN";
+      break;
+    case CLIPBRD_E_CANT_EMPTY:
+      aResult = "CLIPBRD_E_CANT_EMPTY";
+      break;
+    case CLIPBRD_E_CANT_CLOSE:
+      aResult = "CLIPBRD_E_CANT_CLOSE";
+      break;
+    case CLIPBRD_E_CANT_SET:
+      aResult = "CLIPBRD_E_CANT_SET";
+      break;
+    default:
+      // Explicit template instantiaton, because otherwise the call is
+      // ambiguous.
+      constexpr int kRadix = 16;
+      aResult = IntToCString<int32_t>(aHres, kRadix);
+      break;
+  }
+}
+
+// See
+// <https://docs.microsoft.com/en-us/windows/win32/api/ole2/nf-ole2-olesetclipboard>.
+static void LogOleSetClipboardResult(const HRESULT aHres) {
+  if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+    nsAutoCString hresString;
+    OleSetClipboardResultToString(aHres, hresString);
+    MOZ_CLIPBOARD_LOG("OleSetClipboard result: %s", hresString.get());
+  }
+}
+
+template <typename Function, typename LogFunction, typename... Args>
+static HRESULT RepeatedlyTry(Function aFunction, LogFunction aLogFunction,
+                             Args... aArgs) {
+  // These are magic values based on local testing. They are chosen not higher
+  // to avoid jank (<https://developer.mozilla.org/en-US/docs/Glossary/Jank>).
+  // When changing them, be careful.
+  static constexpr int kNumberOfTries = 3;
+  static constexpr int kDelayInMs = 3;
+
+  HRESULT hres;
+  for (int i = 0; i < kNumberOfTries; ++i) {
+    hres = aFunction(aArgs...);
+    aLogFunction(hres);
+
+    if (hres == S_OK) {
+      break;
+    }
+
+    std::this_thread::sleep_for(std::chrono::milliseconds(kDelayInMs));
+  }
+
+  return hres;
+}
+
+// Other apps can block access to the clipboard. This repeatedly
+// calls `::OleSetClipboard` for a fixed number of times and should be called
+// instead of `::OleSetClipboard`.
+static void RepeatedlyTryOleSetClipboard(IDataObject* aDataObj) {
+  RepeatedlyTry(::OleSetClipboard, LogOleSetClipboardResult, aDataObj);
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP nsClipboard::SetNativeClipboardData(
+    nsITransferable* aTransferable, int32_t aWhichClipboard) {
+  MOZ_CLIPBOARD_LOG("%s", __FUNCTION__);
+
+  if (aWhichClipboard != kGlobalClipboard) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // make sure we have a good transferable
+  if (!aTransferable) {
+    return NS_ERROR_FAILURE;
+  }
+
+#ifdef ACCESSIBILITY
+  mozilla::a11y::Compatibility::SuppressA11yForClipboardCopy();
+#endif
+
+  RefPtr<IDataObject> dataObj;
+  auto mightNeedToFlush = MightNeedToFlush::No;
+  if (NS_SUCCEEDED(CreateNativeDataObject(aTransferable,
+                                          getter_AddRefs(dataObj), nullptr,
+                                          &mightNeedToFlush))) {
+    RepeatedlyTryOleSetClipboard(dataObj);
+
+    const bool doFlush = [&] {
+      switch (mozilla::StaticPrefs::widget_windows_sync_clipboard_flush()) {
+        case 0:
+          return false;
+        case 1:
+          return true;
+        default:
+          // Bug 1774285: Windows Suggested Actions (introduced in Windows 11
+          // 22H2) walks the entire a11y tree using UIA if something is placed
+          // on the clipboard using delayed rendering. (The OLE clipboard always
+          // uses delayed rendering.) This a11y tree walk causes an unacceptable
+          // hang, particularly when the a11y cache is disabled. We choose the
+          // lesser of the two performance/memory evils here and force immediate
+          // rendering as part of our workaround.
+          return mightNeedToFlush == MightNeedToFlush::Yes &&
+                 mozilla::IsWin1122H2OrLater();
+      }
+    }();
+    if (doFlush) {
+      RepeatedlyTry(::OleFlushClipboard, [](HRESULT) {});
+    }
+  } else {
+    // Clear the native clipboard
+    RepeatedlyTryOleSetClipboard(nullptr);
+  }
+
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+nsresult nsClipboard::GetGlobalData(HGLOBAL aHGBL, void** aData,
+                                    uint32_t* aLen) {
+  MOZ_CLIPBOARD_LOG("%s", __FUNCTION__);
+
+  // Allocate a new memory buffer and copy the data from global memory.
+  // Recall that win98 allocates to nearest DWORD boundary. As a safety
+  // precaution, allocate an extra 3 bytes (but don't report them in |aLen|!)
+  // and null them out to ensure that all of our NS_strlen calls will succeed.
+  // NS_strlen operates on char16_t, so we need 3 NUL bytes to ensure it finds
+  // a full NUL char16_t when |*aLen| is odd.
+  nsresult result = NS_ERROR_FAILURE;
+  if (aHGBL != nullptr) {
+    LPSTR lpStr = (LPSTR)GlobalLock(aHGBL);
+    mozilla::CheckedInt<uint32_t> allocSize =
+        mozilla::CheckedInt<uint32_t>(GlobalSize(aHGBL)) + 3;
+    if (!allocSize.isValid()) {
+      return NS_ERROR_INVALID_ARG;
+    }
+    char* data = static_cast<char*>(malloc(allocSize.value()));
+    if (data) {
+      uint32_t size = allocSize.value() - 3;
+      memcpy(data, lpStr, size);
+      // null terminate for safety
+      data[size] = data[size + 1] = data[size + 2] = '\0';
+
+      GlobalUnlock(aHGBL);
+      *aData = data;
+      *aLen = size;
+
+      result = NS_OK;
+    }
+  } else {
+    // We really shouldn't ever get here
+    // but just in case
+    *aData = nullptr;
+    *aLen = 0;
+    LPVOID lpMsgBuf;
+
+    FormatMessageW(
+        FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM, nullptr,
+        GetLastError(),
+        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),  // Default language
+        (LPWSTR)&lpMsgBuf, 0, nullptr);
+
+    // Display the string.
+    MessageBoxW(nullptr, (LPCWSTR)lpMsgBuf, L"GetLastError",
+                MB_OK | MB_ICONINFORMATION);
+
+    // Free the buffer.
+    LocalFree(lpMsgBuf);
+  }
+
+  return result;
+}
+
+//-------------------------------------------------------------------------
+nsresult nsClipboard::GetNativeDataOffClipboard(nsIWidget* aWidget,
+                                                UINT /*aIndex*/, UINT aFormat,
+                                                void** aData, uint32_t* aLen) {
+  MOZ_CLIPBOARD_LOG("%s: overload taking nsIWidget*.", __FUNCTION__);
+
+  HGLOBAL hglb;
+  nsresult result = NS_ERROR_FAILURE;
+
+  HWND nativeWin = nullptr;
+  if (::OpenClipboard(nativeWin)) {
+    hglb = ::GetClipboardData(aFormat);
+    result = GetGlobalData(hglb, aData, aLen);
+    ::CloseClipboard();
+  }
+  return result;
+}
+
+// See methods listed at
+// <https://docs.microsoft.com/en-us/windows/win32/api/objidl/nn-objidl-idataobject#methods>.
+static void LogIDataObjectMethodResult(const HRESULT aHres,
+                                       const nsCString& aMethodName) {
+  if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+    nsAutoCString hresString;
+    IDataObjectMethodResultToString(aHres, hresString);
+    MOZ_CLIPBOARD_LOG("IDataObject::%s result : %s", aMethodName.get(),
+                      hresString.get());
+  }
+}
+
+// Other apps can block access to the clipboard. This repeatedly calls
+// `GetData` for a fixed number of times and should be called instead of
+// `GetData`. See
+// <https://docs.microsoft.com/en-us/windows/win32/api/objidl/nf-objidl-idataobject-getdata>.
+// While Microsoft's documentation doesn't include `CLIPBRD_E_CANT_OPEN`
+// explicitly, it allows it implicitly and in local experiments it was indeed
+// returned.
+static HRESULT RepeatedlyTryGetData(IDataObject& aDataObject, LPFORMATETC pFE,
+                                    LPSTGMEDIUM pSTM) {
+  return RepeatedlyTry(
+      [&aDataObject, &pFE, &pSTM]() { return aDataObject.GetData(pFE, pSTM); },
+      std::bind(LogIDataObjectMethodResult, std::placeholders::_1,
+                "GetData"_ns));
+}
+
+//-------------------------------------------------------------------------
+// static
+HRESULT nsClipboard::FillSTGMedium(IDataObject* aDataObject, UINT aFormat,
+                                   LPFORMATETC pFE, LPSTGMEDIUM pSTM,
+                                   DWORD aTymed) {
+  SET_FORMATETC(*pFE, aFormat, 0, DVASPECT_CONTENT, -1, aTymed);
+
+  // Starting by querying for the data to see if we can get it as from global
+  // memory
+  HRESULT hres = S_FALSE;
+  hres = aDataObject->QueryGetData(pFE);
+  LogIDataObjectMethodResult(hres, "QueryGetData"_ns);
+  if (S_OK == hres) {
+    hres = RepeatedlyTryGetData(*aDataObject, pFE, pSTM);
+  }
+  return hres;
+}
+
+//-------------------------------------------------------------------------
+// If aFormat is CF_DIBV5, aMIMEImageFormat must be a type for which we have
+// an image encoder (e.g. image/png).
+// For other values of aFormat, it is OK to pass null for aMIMEImageFormat.
+nsresult nsClipboard::GetNativeDataOffClipboard(IDataObject* aDataObject,
+                                                UINT aIndex, UINT aFormat,
+                                                const char* aMIMEImageFormat,
+                                                void** aData, uint32_t* aLen) {
+  MOZ_CLIPBOARD_LOG("%s: overload taking IDataObject*.", __FUNCTION__);
+
+  nsresult result = NS_ERROR_FAILURE;
+  *aData = nullptr;
+  *aLen = 0;
+
+  if (!aDataObject) {
+    return result;
+  }
+
+  UINT format = aFormat;
+  HRESULT hres = S_FALSE;
+
+  // XXX at the moment we only support global memory transfers
+  // It is here where we will add support for native images
+  // and IStream
+  FORMATETC fe;
+  STGMEDIUM stm;
+  hres = FillSTGMedium(aDataObject, format, &fe, &stm, TYMED_HGLOBAL);
+
+  // If the format is CF_HDROP and we haven't found any files we can try looking
+  // for virtual files with FILEDESCRIPTOR.
+  if (FAILED(hres) && format == CF_HDROP) {
+    hres = FillSTGMedium(aDataObject,
+                         nsClipboard::GetClipboardFileDescriptorFormatW(), &fe,
+                         &stm, TYMED_HGLOBAL);
+    if (FAILED(hres)) {
+      hres = FillSTGMedium(aDataObject,
+                           nsClipboard::GetClipboardFileDescriptorFormatA(),
+                           &fe, &stm, TYMED_HGLOBAL);
+    }
+  }
+
+  // Currently this is only handling TYMED_HGLOBAL data
+  // For Text, Dibs, Files, and generic data (like HTML)
+  if (S_OK == hres) {
+    static CLIPFORMAT fileDescriptorFlavorA =
+        ::RegisterClipboardFormat(CFSTR_FILEDESCRIPTORA);
+    static CLIPFORMAT fileDescriptorFlavorW =
+        ::RegisterClipboardFormat(CFSTR_FILEDESCRIPTORW);
+    static CLIPFORMAT fileFlavor =
+        ::RegisterClipboardFormat(CFSTR_FILECONTENTS);
+    static CLIPFORMAT preferredDropEffect =
+        ::RegisterClipboardFormat(CFSTR_PREFERREDDROPEFFECT);
+
+    switch (stm.tymed) {
+      case TYMED_HGLOBAL: {
+        switch (fe.cfFormat) {
+          case CF_TEXT: {
+            // Get the data out of the global data handle. The size we
+            // return should not include the null because the other
+            // platforms don't use nulls, so just return the length we get
+            // back from strlen(), since we know CF_TEXT is null
+            // terminated. Recall that GetGlobalData() returns the size of
+            // the allocated buffer, not the size of the data (on 98, these
+            // are not the same) so we can't use that.
+            uint32_t allocLen = 0;
+            if (NS_SUCCEEDED(GetGlobalData(stm.hGlobal, aData, &allocLen))) {
+              *aLen = strlen(reinterpret_cast<char*>(*aData));
+              result = NS_OK;
+            }
+          } break;
+
+          case CF_UNICODETEXT: {
+            // Get the data out of the global data handle. The size we
+            // return should not include the null because the other
+            // platforms don't use nulls, so just return the length we get
+            // back from strlen(), since we know CF_UNICODETEXT is null
+            // terminated. Recall that GetGlobalData() returns the size of
+            // the allocated buffer, not the size of the data (on 98, these
+            // are not the same) so we can't use that.
+            uint32_t allocLen = 0;
+            if (NS_SUCCEEDED(GetGlobalData(stm.hGlobal, aData, &allocLen))) {
+              *aLen = NS_strlen(reinterpret_cast<char16_t*>(*aData)) * 2;
+              result = NS_OK;
+            }
+          } break;
+
+          case CF_DIBV5:
+            if (aMIMEImageFormat) {
+              uint32_t allocLen = 0;
+              const char* clipboardData;
+              if (NS_SUCCEEDED(GetGlobalData(
+                      stm.hGlobal, (void**)&clipboardData, &allocLen))) {
+                nsCOMPtr<imgIContainer> container;
+                nsCOMPtr<imgITools> imgTools =
+                    do_CreateInstance("@mozilla.org/image/tools;1");
+                result = imgTools->DecodeImageFromBuffer(
+                    clipboardData, allocLen,
+                    nsLiteralCString(IMAGE_BMP_MS_CLIPBOARD),
+                    getter_AddRefs(container));
+                if (NS_FAILED(result)) {
+                  break;
+                }
+
+                nsAutoCString mimeType;
+                if (strcmp(aMIMEImageFormat, kJPGImageMime) == 0) {
+                  mimeType.Assign(IMAGE_JPEG);
+                } else {
+                  mimeType.Assign(aMIMEImageFormat);
+                }
+
+                nsCOMPtr<nsIInputStream> inputStream;
+                result = imgTools->EncodeImage(container, mimeType, u""_ns,
+                                               getter_AddRefs(inputStream));
+                if (NS_FAILED(result)) {
+                  break;
+                }
+
+                if (!inputStream) {
+                  result = NS_ERROR_FAILURE;
+                  break;
+                }
+
+                *aData = inputStream.forget().take();
+                *aLen = sizeof(nsIInputStream*);
+              }
+            }
+            break;
+
+          case CF_HDROP: {
+            // in the case of a file drop, multiple files are stashed within a
+            // single data object. In order to match mozilla's D&D apis, we
+            // just pull out the file at the requested index, pretending as
+            // if there really are multiple drag items.
+            HDROP dropFiles = (HDROP)GlobalLock(stm.hGlobal);
+
+            UINT numFiles = ::DragQueryFileW(dropFiles, 0xFFFFFFFF, nullptr, 0);
+            NS_ASSERTION(numFiles > 0,
+                         "File drop flavor, but no files...hmmmm");
+            NS_ASSERTION(aIndex < numFiles,
+                         "Asked for a file index out of range of list");
+            if (numFiles > 0) {
+              UINT fileNameLen =
+                  ::DragQueryFileW(dropFiles, aIndex, nullptr, 0);
+              wchar_t* buffer = reinterpret_cast<wchar_t*>(
+                  moz_xmalloc((fileNameLen + 1) * sizeof(wchar_t)));
+              ::DragQueryFileW(dropFiles, aIndex, buffer, fileNameLen + 1);
+              *aData = buffer;
+              *aLen = fileNameLen * sizeof(char16_t);
+              result = NS_OK;
+            }
+            GlobalUnlock(stm.hGlobal);
+
+          } break;
+
+          default: {
+            if (fe.cfFormat == fileDescriptorFlavorA ||
+                fe.cfFormat == fileDescriptorFlavorW) {
+              nsAutoString tempPath;
+
+              LPFILEGROUPDESCRIPTOR fgdesc =
+                  static_cast<LPFILEGROUPDESCRIPTOR>(GlobalLock(stm.hGlobal));
+              if (fgdesc) {
+                result = GetTempFilePath(
+                    nsDependentString((fgdesc->fgd)[aIndex].cFileName),
+                    tempPath);
+                GlobalUnlock(stm.hGlobal);
+              }
+              if (NS_FAILED(result)) {
+                break;
+              }
+              result = SaveStorageOrStream(aDataObject, aIndex, tempPath);
+              if (NS_FAILED(result)) {
+                break;
+              }
+              wchar_t* buffer = reinterpret_cast<wchar_t*>(
+                  moz_xmalloc((tempPath.Length() + 1) * sizeof(wchar_t)));
+              wcscpy(buffer, tempPath.get());
+              *aData = buffer;
+              *aLen = tempPath.Length() * sizeof(wchar_t);
+              result = NS_OK;
+            } else if (fe.cfFormat == fileFlavor) {
+              NS_WARNING(
+                  "Mozilla doesn't yet understand how to read this type of "
+                  "file flavor");
+            } else {
+              // Get the data out of the global data handle. The size we
+              // return should not include the null because the other
+              // platforms don't use nulls, so just return the length we get
+              // back from strlen(), since we know CF_UNICODETEXT is null
+              // terminated. Recall that GetGlobalData() returns the size of
+              // the allocated buffer, not the size of the data (on 98, these
+              // are not the same) so we can't use that.
+              //
+              // NOTE: we are assuming that anything that falls into this
+              //        default case is unicode. As we start to get more
+              //        kinds of binary data, this may become an incorrect
+              //        assumption. Stay tuned.
+              uint32_t allocLen = 0;
+              if (NS_SUCCEEDED(GetGlobalData(stm.hGlobal, aData, &allocLen))) {
+                if (fe.cfFormat == GetHtmlClipboardFormat()) {
+                  // CF_HTML is actually UTF8, not unicode, so disregard the
+                  // assumption above. We have to check the header for the
+                  // actual length, and we'll do that in FindPlatformHTML().
+                  // For now, return the allocLen. This case is mostly to
+                  // ensure we don't try to call strlen on the buffer.
+                  *aLen = allocLen;
+                } else if (fe.cfFormat == GetCustomClipboardFormat()) {
+                  // Binary data
+                  *aLen = allocLen;
+                } else if (fe.cfFormat == preferredDropEffect) {
+                  // As per the MSDN doc entitled: "Shell Clipboard Formats"
+                  // CFSTR_PREFERREDDROPEFFECT should return a DWORD
+                  // Reference:
+                  // http://msdn.microsoft.com/en-us/library/bb776902(v=vs.85).aspx
+                  NS_ASSERTION(
+                      allocLen == sizeof(DWORD),
+                      "CFSTR_PREFERREDDROPEFFECT should return a DWORD");
+                  *aLen = allocLen;
+                } else {
+                  *aLen = NS_strlen(reinterpret_cast<char16_t*>(*aData)) *
+                          sizeof(char16_t);
+                }
+                result = NS_OK;
+              }
+            }
+          } break;
+        }  // switch
+      } break;
+
+      case TYMED_GDI: {
+#ifdef DEBUG
+        MOZ_CLIPBOARD_LOG("*********************** TYMED_GDI");
+#endif
+      } break;
+
+      default:
+        break;
+    }  // switch
+
+    ReleaseStgMedium(&stm);
+  }
+
+  return result;
+}
+
+//-------------------------------------------------------------------------
+nsresult nsClipboard::GetDataFromDataObject(IDataObject* aDataObject,
+                                            UINT anIndex, nsIWidget* aWindow,
+                                            nsITransferable* aTransferable) {
+  MOZ_CLIPBOARD_LOG("%s", __FUNCTION__);
+
+  // make sure we have a good transferable
+  if (!aTransferable) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  nsresult res = NS_ERROR_FAILURE;
+
+  // get flavor list that includes all flavors that can be written (including
+  // ones obtained through conversion)
+  nsTArray<nsCString> flavors;
+  res = aTransferable->FlavorsTransferableCanImport(flavors);
+  if (NS_FAILED(res)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Walk through flavors and see which flavor is on the clipboard them on the
+  // native clipboard,
+  for (uint32_t i = 0; i < flavors.Length(); i++) {
+    nsCString& flavorStr = flavors[i];
+    UINT format = GetFormat(flavorStr.get());
+
+    // Try to get the data using the desired flavor. This might fail, but all is
+    // not lost.
+    void* data = nullptr;
+    uint32_t dataLen = 0;
+    bool dataFound = false;
+    if (nullptr != aDataObject) {
+      if (NS_SUCCEEDED(GetNativeDataOffClipboard(aDataObject, anIndex, format,
+                                                 flavorStr.get(), &data,
+                                                 &dataLen))) {
+        dataFound = true;
+      }
+    } else if (nullptr != aWindow) {
+      if (NS_SUCCEEDED(GetNativeDataOffClipboard(aWindow, anIndex, format,
+                                                 &data, &dataLen))) {
+        dataFound = true;
+      }
+    }
+
+    // This is our second chance to try to find some data, having not found it
+    // when directly asking for the flavor. Let's try digging around in other
+    // flavors to help satisfy our craving for data.
+    if (!dataFound) {
+      if (flavorStr.EqualsLiteral(kTextMime)) {
+        dataFound =
+            FindUnicodeFromPlainText(aDataObject, anIndex, &data, &dataLen);
+      } else if (flavorStr.EqualsLiteral(kURLMime)) {
+        // drags from other windows apps expose the native
+        // CFSTR_INETURL{A,W} flavor
+        dataFound = FindURLFromNativeURL(aDataObject, anIndex, &data, &dataLen);
+        if (!dataFound) {
+          dataFound =
+              FindURLFromLocalFile(aDataObject, anIndex, &data, &dataLen);
+        }
+      }
+    }  // if we try one last ditch effort to find our data
+
+    // Hopefully by this point we've found it and can go about our business
+    if (dataFound) {
+      nsCOMPtr<nsISupports> genericDataWrapper;
+      if (flavorStr.EqualsLiteral(kFileMime)) {
+        // we have a file path in |data|. Create an nsLocalFile object.
+        nsDependentString filepath(reinterpret_cast<char16_t*>(data));
+        nsCOMPtr<nsIFile> file;
+        if (NS_SUCCEEDED(
+                NS_NewLocalFile(filepath, false, getter_AddRefs(file)))) {
+          genericDataWrapper = do_QueryInterface(file);
+        }
+        free(data);
+      } else if (flavorStr.EqualsLiteral(kNativeHTMLMime)) {
+        uint32_t dummy;
+        // the editor folks want CF_HTML exactly as it's on the clipboard, no
+        // conversions, no fancy stuff. Pull it off the clipboard, stuff it into
+        // a wrapper and hand it back to them.
+        if (FindPlatformHTML(aDataObject, anIndex, &data, &dummy, &dataLen)) {
+          nsPrimitiveHelpers::CreatePrimitiveForData(
+              flavorStr, data, dataLen, getter_AddRefs(genericDataWrapper));
+        } else {
+          free(data);
+          continue;  // something wrong with this flavor, keep looking for other
+                     // data
+        }
+        free(data);
+      } else if (flavorStr.EqualsLiteral(kHTMLMime)) {
+        uint32_t startOfData = 0;
+        // The JS folks want CF_HTML exactly as it is on the clipboard, but
+        // minus the CF_HTML header index information.
+        // It also needs to be converted to UTF16 and have linebreaks changed.
+        if (FindPlatformHTML(aDataObject, anIndex, &data, &startOfData,
+                             &dataLen)) {
+          dataLen -= startOfData;
+          nsPrimitiveHelpers::CreatePrimitiveForCFHTML(
+              static_cast<char*>(data) + startOfData, &dataLen,
+              getter_AddRefs(genericDataWrapper));
+        } else {
+          free(data);
+          continue;  // something wrong with this flavor, keep looking for other
+                     // data
+        }
+        free(data);
+      } else if (flavorStr.EqualsLiteral(kJPEGImageMime) ||
+                 flavorStr.EqualsLiteral(kJPGImageMime) ||
+                 flavorStr.EqualsLiteral(kPNGImageMime)) {
+        nsIInputStream* imageStream = reinterpret_cast<nsIInputStream*>(data);
+        genericDataWrapper = do_QueryInterface(imageStream);
+        NS_IF_RELEASE(imageStream);
+      } else {
+        // Treat custom types as a string of bytes.
+        if (!flavorStr.EqualsLiteral(kCustomTypesMime)) {
+          bool isRTF = flavorStr.EqualsLiteral(kRTFMime);
+          // we probably have some form of text. The DOM only wants LF, so
+          // convert from Win32 line endings to DOM line endings.
+          int32_t signedLen = static_cast<int32_t>(dataLen);
+          nsLinebreakHelpers::ConvertPlatformToDOMLinebreaks(isRTF, &data,
+                                                             &signedLen);
+          dataLen = signedLen;
+
+          if (isRTF) {
+            // RTF on Windows is known to sometimes deliver an extra null byte.
+            if (dataLen > 0 && static_cast<char*>(data)[dataLen - 1] == '\0') {
+              dataLen--;
+            }
+          }
+        }
+
+        nsPrimitiveHelpers::CreatePrimitiveForData(
+            flavorStr, data, dataLen, getter_AddRefs(genericDataWrapper));
+        free(data);
+      }
+
+      NS_ASSERTION(genericDataWrapper,
+                   "About to put null data into the transferable");
+      aTransferable->SetTransferData(flavorStr.get(), genericDataWrapper);
+      res = NS_OK;
+
+      // we found one, get out of the loop
+      break;
+    }
+  }  // foreach flavor
+
+  return res;
+}
+
+//
+// FindPlatformHTML
+//
+// Someone asked for the OS CF_HTML flavor. We give it back to them exactly
+// as-is.
+//
+bool nsClipboard ::FindPlatformHTML(IDataObject* inDataObject, UINT inIndex,
+                                    void** outData, uint32_t* outStartOfData,
+                                    uint32_t* outDataLen) {
+  // Reference: MSDN doc entitled "HTML Clipboard Format"
+  // http://msdn.microsoft.com/en-us/library/aa767917(VS.85).aspx#unknown_854
+  // CF_HTML is UTF8, not unicode. We also can't rely on it being
+  // null-terminated so we have to check the CF_HTML header for the correct
+  // length. The length we return is the bytecount from the beginning of the
+  // selected data to the end of the selected data, without the null
+  // termination. Because it's UTF8, we're guaranteed the header is ASCII.
+
+  if (!outData || !*outData) {
+    return false;
+  }
+
+  char version[8] = {0};
+  int32_t startOfData = 0;
+  int32_t endOfData = 0;
+  int numFound =
+      sscanf((char*)*outData, "Version:%7s\nStartHTML:%d\nEndHTML:%d", version,
+             &startOfData, &endOfData);
+
+  if (numFound != 3 || startOfData < -1 || endOfData < -1) {
+    return false;
+  }
+
+  // Fixup the start and end markers if they have no context (set to -1)
+  if (startOfData == -1) {
+    startOfData = 0;
+  }
+  if (endOfData == -1) {
+    endOfData = *outDataLen;
+  }
+
+  // Make sure we were passed sane values within our buffer size.
+  // (Note that we've handled all cases of negative endOfData above, so we can
+  // safely cast it to be unsigned here.)
+  if (!endOfData || startOfData >= endOfData ||
+      static_cast<uint32_t>(endOfData) > *outDataLen) {
+    return false;
+  }
+
+  // We want to return the buffer not offset by startOfData because it will be
+  // parsed out later (probably by HTMLEditor::ParseCFHTML) when it is still
+  // in CF_HTML format.
+
+  // We return the byte offset from the start of the data buffer to where the
+  // HTML data starts. The caller might want to extract the HTML only.
+  *outStartOfData = startOfData;
+  *outDataLen = endOfData;
+  return true;
+}
+
+//
+// FindUnicodeFromPlainText
+//
+// Looks for CF_TEXT on the clipboard and converts it into an UTF-16 string
+// if present. Returns this string in outData, and its length in outDataLen.
+// XXXndeakin Windows converts between CF_UNICODE and CF_TEXT automatically
+// so it doesn't seem like this is actually needed.
+//
+bool nsClipboard ::FindUnicodeFromPlainText(IDataObject* inDataObject,
+                                            UINT inIndex, void** outData,
+                                            uint32_t* outDataLen) {
+  MOZ_CLIPBOARD_LOG("%s", __FUNCTION__);
+
+  // We are looking for text/plain and we failed to find it on the clipboard
+  // first, so try again with CF_TEXT. If that is present, convert it to
+  // unicode.
+  nsresult rv = GetNativeDataOffClipboard(inDataObject, inIndex, CF_TEXT,
+                                          nullptr, outData, outDataLen);
+  if (NS_FAILED(rv) || !*outData) {
+    return false;
+  }
+
+  const char* castedText = static_cast<char*>(*outData);
+  nsAutoString tmp;
+  rv = NS_CopyNativeToUnicode(nsDependentCSubstring(castedText, *outDataLen),
+                              tmp);
+  if (NS_FAILED(rv)) {
+    return false;
+  }
+
+  // out with the old, in with the new
+  free(*outData);
+  *outData = ToNewUnicode(tmp);
+  *outDataLen = tmp.Length() * sizeof(char16_t);
+
+  return true;
+
+}  // FindUnicodeFromPlainText
+
+//
+// FindURLFromLocalFile
+//
+// we are looking for a URL and couldn't find it, try again with looking for
+// a local file. If we have one, it may either be a normal file or an internet
+// shortcut. In both cases, however, we can get a URL (it will be a file:// url
+// in the local file case).
+//
+bool nsClipboard ::FindURLFromLocalFile(IDataObject* inDataObject, UINT inIndex,
+                                        void** outData, uint32_t* outDataLen) {
+  MOZ_CLIPBOARD_LOG("%s", __FUNCTION__);
+
+  bool dataFound = false;
+
+  nsresult loadResult =
+      GetNativeDataOffClipboard(inDataObject, inIndex, GetFormat(kFileMime),
+                                nullptr, outData, outDataLen);
+  if (NS_SUCCEEDED(loadResult) && *outData) {
+    // we have a file path in |data|. Is it an internet shortcut or a normal
+    // file?
+    const nsDependentString filepath(static_cast<char16_t*>(*outData));
+    nsCOMPtr<nsIFile> file;
+    nsresult rv = NS_NewLocalFile(filepath, true, getter_AddRefs(file));
+    if (NS_FAILED(rv)) {
+      free(*outData);
+      return dataFound;
+    }
+
+    if (IsInternetShortcut(filepath)) {
+      free(*outData);
+      nsAutoCString url;
+      ResolveShortcut(file, url);
+      if (!url.IsEmpty()) {
+        // convert it to unicode and pass it out
+        NS_ConvertUTF8toUTF16 urlString(url);
+        // the internal mozilla URL format, text/x-moz-url, contains
+        // URL\ntitle.  We can guess the title from the file's name.
+        nsAutoString title;
+        file->GetLeafName(title);
+        // We rely on IsInternetShortcut check that file has a .url extension.
+        title.SetLength(title.Length() - 4);
+        if (title.IsEmpty()) {
+          title = urlString;
+        }
+        *outData = ToNewUnicode(urlString + u"\n"_ns + title);
+        *outDataLen =
+            NS_strlen(static_cast<char16_t*>(*outData)) * sizeof(char16_t);
+
+        dataFound = true;
+      }
+    } else {
+      // we have a normal file, use some Necko objects to get our file path
+      nsAutoCString urlSpec;
+      NS_GetURLSpecFromFile(file, urlSpec);
+
+      // convert it to unicode and pass it out
+      free(*outData);
+      *outData = UTF8ToNewUnicode(urlSpec);
+      *outDataLen =
+          NS_strlen(static_cast<char16_t*>(*outData)) * sizeof(char16_t);
+      dataFound = true;
+    }  // else regular file
+  }
+
+  return dataFound;
+}  // FindURLFromLocalFile
+
+//
+// FindURLFromNativeURL
+//
+// we are looking for a URL and couldn't find it using our internal
+// URL flavor, so look for it using the native URL flavor,
+// CF_INETURLSTRW (We don't handle CF_INETURLSTRA currently)
+//
+bool nsClipboard ::FindURLFromNativeURL(IDataObject* inDataObject, UINT inIndex,
+                                        void** outData, uint32_t* outDataLen) {
+  MOZ_CLIPBOARD_LOG("%s", __FUNCTION__);
+
+  bool dataFound = false;
+
+  void* tempOutData = nullptr;
+  uint32_t tempDataLen = 0;
+
+  nsresult loadResult = GetNativeDataOffClipboard(
+      inDataObject, inIndex, ::RegisterClipboardFormat(CFSTR_INETURLW), nullptr,
+      &tempOutData, &tempDataLen);
+  if (NS_SUCCEEDED(loadResult) && tempOutData) {
+    nsDependentString urlString(static_cast<char16_t*>(tempOutData));
+    // the internal mozilla URL format, text/x-moz-url, contains
+    // URL\ntitle.  Since we don't actually have a title here,
+    // just repeat the URL to fake it.
+    *outData = ToNewUnicode(urlString + u"\n"_ns + urlString);
+    *outDataLen =
+        NS_strlen(static_cast<char16_t*>(*outData)) * sizeof(char16_t);
+    free(tempOutData);
+    dataFound = true;
+  } else {
+    loadResult = GetNativeDataOffClipboard(
+        inDataObject, inIndex, ::RegisterClipboardFormat(CFSTR_INETURLA),
+        nullptr, &tempOutData, &tempDataLen);
+    if (NS_SUCCEEDED(loadResult) && tempOutData) {
+      // CFSTR_INETURLA is (currently) equal to CFSTR_SHELLURL which is equal to
+      // CF_TEXT which is by definition ANSI encoded.
+      nsCString urlUnescapedA;
+      bool unescaped =
+          NS_UnescapeURL(static_cast<char*>(tempOutData), tempDataLen,
+                         esc_OnlyNonASCII | esc_SkipControl, urlUnescapedA);
+
+      nsString urlString;
+      if (unescaped) {
+        NS_CopyNativeToUnicode(urlUnescapedA, urlString);
+      } else {
+        NS_CopyNativeToUnicode(
+            nsDependentCString(static_cast<char*>(tempOutData), tempDataLen),
+            urlString);
+      }
+
+      // the internal mozilla URL format, text/x-moz-url, contains
+      // URL\ntitle.  Since we don't actually have a title here,
+      // just repeat the URL to fake it.
+      *outData = ToNewUnicode(urlString + u"\n"_ns + urlString);
+      *outDataLen =
+          NS_strlen(static_cast<char16_t*>(*outData)) * sizeof(char16_t);
+      free(tempOutData);
+      dataFound = true;
+    }
+  }
+
+  return dataFound;
+}  // FindURLFromNativeURL
+
+// Other apps can block access to the clipboard. This repeatedly
+// calls `::OleGetClipboard` for a fixed number of times and should be called
+// instead of `::OleGetClipboard`.
+static HRESULT RepeatedlyTryOleGetClipboard(IDataObject** aDataObj) {
+  return RepeatedlyTry(::OleGetClipboard, LogOleGetClipboardResult, aDataObj);
+}
+
+//
+// ResolveShortcut
+//
+void nsClipboard ::ResolveShortcut(nsIFile* aFile, nsACString& outURL) {
+  nsCOMPtr<nsIFileProtocolHandler> fph;
+  nsresult rv = NS_GetFileProtocolHandler(getter_AddRefs(fph));
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  nsCOMPtr<nsIURI> uri;
+  rv = fph->ReadURLFile(aFile, getter_AddRefs(uri));
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  uri->GetSpec(outURL);
+}  // ResolveShortcut
+
+//
+// IsInternetShortcut
+//
+// A file is an Internet Shortcut if it ends with .URL
+//
+bool nsClipboard ::IsInternetShortcut(const nsAString& inFileName) {
+  return StringEndsWith(inFileName, u".url"_ns,
+                        nsCaseInsensitiveStringComparator);
+}  // IsInternetShortcut
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  MOZ_CLIPBOARD_LOG("%s aWhichClipboard=%i", __FUNCTION__, aWhichClipboard);
+
+  nsresult res;
+  // This makes sure we can use the OLE functionality for the clipboard
+  IDataObject* dataObj;
+  if (S_OK == RepeatedlyTryOleGetClipboard(&dataObj)) {
+    // Use OLE IDataObject for clipboard operations
+    MOZ_CLIPBOARD_LOG("    use OLE IDataObject:");
+    if (MOZ_CLIPBOARD_LOG_ENABLED()) {
+      IEnumFORMATETC* pEnum = nullptr;
+      if (S_OK == dataObj->EnumFormatEtc(DATADIR_GET, &pEnum)) {
+        FORMATETC fEtc;
+        while (S_OK == pEnum->Next(1, &fEtc, nullptr)) {
+          nsAutoString format;
+          mozilla::widget::WinUtils::GetClipboardFormatAsString(fEtc.cfFormat,
+                                                                format);
+          MOZ_CLIPBOARD_LOG("        FORMAT %s",
+                            NS_ConvertUTF16toUTF8(format).get());
+        }
+      }
+      pEnum->Release();
+    }
+
+    res = GetDataFromDataObject(dataObj, 0, nullptr, aTransferable);
+    dataObj->Release();
+  } else {
+    // do it the old manual way
+    res = GetDataFromDataObject(nullptr, 0, mWindow, aTransferable);
+  }
+  return res;
+}
+
+nsresult nsClipboard::EmptyNativeClipboardData(int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+  // Some programs such as ZoneAlarm monitor clipboard usage and then open the
+  // clipboard to scan it.  If we i) empty and then ii) set data, then the
+  // 'set data' can sometimes fail with access denied becacuse another program
+  // has the clipboard open.  So to avoid this race condition for OpenClipboard
+  // we do not empty the clipboard when we're setting it.
+  RepeatedlyTryOleSetClipboard(nullptr);
+  return NS_OK;
+}
+
+mozilla::Result<int32_t, nsresult>
+nsClipboard::GetNativeClipboardSequenceNumber(int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(kGlobalClipboard == aWhichClipboard);
+  return (int32_t)::GetClipboardSequenceNumber();
+}
+
+//-------------------------------------------------------------------------
+mozilla::Result<bool, nsresult>
+nsClipboard::HasNativeClipboardDataMatchingFlavors(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+  for (const auto& flavor : aFlavorList) {
+    UINT format = GetFormat(flavor.get());
+    if (IsClipboardFormatAvailable(format)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+//-------------------------------------------------------------------------
+nsresult nsClipboard::GetTempFilePath(const nsAString& aFileName,
+                                      nsAString& aFilePath) {
+  nsresult result = NS_OK;
+
+  nsCOMPtr<nsIFile> tmpFile;
+  result =
+      GetSpecialSystemDirectory(OS_TemporaryDirectory, getter_AddRefs(tmpFile));
+  NS_ENSURE_SUCCESS(result, result);
+
+  result = tmpFile->Append(aFileName);
+  NS_ENSURE_SUCCESS(result, result);
+
+  result = tmpFile->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0660);
+  NS_ENSURE_SUCCESS(result, result);
+  result = tmpFile->GetPath(aFilePath);
+
+  return result;
+}
+
+//-------------------------------------------------------------------------
+nsresult nsClipboard::SaveStorageOrStream(IDataObject* aDataObject, UINT aIndex,
+                                          const nsAString& aFileName) {
+  NS_ENSURE_ARG_POINTER(aDataObject);
+
+  FORMATETC fe = {0};
+  SET_FORMATETC(fe, RegisterClipboardFormat(CFSTR_FILECONTENTS), 0,
+                DVASPECT_CONTENT, aIndex, TYMED_ISTORAGE | TYMED_ISTREAM);
+
+  STGMEDIUM stm = {0};
+  HRESULT hres = aDataObject->GetData(&fe, &stm);
+  if (FAILED(hres)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  auto releaseMediumGuard =
+      mozilla::MakeScopeExit([&] { ReleaseStgMedium(&stm); });
+
+  // We do this check because, even though we *asked* for IStorage or IStream,
+  // it seems that IDataObject providers can just hand us back whatever they
+  // feel like. See Bug 1824644 for a fun example of that!
+  if (stm.tymed != TYMED_ISTORAGE && stm.tymed != TYMED_ISTREAM) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (stm.tymed == TYMED_ISTORAGE) {
+    RefPtr<IStorage> file;
+    hres = StgCreateStorageEx(
+        aFileName.Data(), STGM_CREATE | STGM_READWRITE | STGM_SHARE_EXCLUSIVE,
+        STGFMT_STORAGE, 0, NULL, NULL, IID_IStorage, getter_AddRefs(file));
+    if (FAILED(hres)) {
+      return NS_ERROR_FAILURE;
+    }
+
+    hres = stm.pstg->CopyTo(0, NULL, NULL, file);
+    if (FAILED(hres)) {
+      return NS_ERROR_FAILURE;
+    }
+
+    file->Commit(STGC_DEFAULT);
+
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(stm.tymed == TYMED_ISTREAM);
+
+  HANDLE handle = CreateFile(aFileName.Data(), GENERIC_WRITE, FILE_SHARE_READ,
+                             NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+  if (handle == INVALID_HANDLE_VALUE) {
+    return NS_ERROR_FAILURE;
+  }
+
+  auto fileCloseGuard = mozilla::MakeScopeExit([&] { CloseHandle(handle); });
+
+  const ULONG bufferSize = 4096;
+  char buffer[bufferSize] = {0};
+  ULONG bytesRead = 0;
+  DWORD bytesWritten = 0;
+  while (true) {
+    HRESULT result = stm.pstm->Read(buffer, bufferSize, &bytesRead);
+    if (FAILED(result)) {
+      return NS_ERROR_FAILURE;
+    }
+    if (bytesRead == 0) {
+      break;
+    }
+    if (!WriteFile(handle, buffer, static_cast<DWORD>(bytesRead), &bytesWritten,
+                   NULL)) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+  return NS_OK;
+}
diff --git a/widget/windows/nsClipboard.h b/widget/windows/nsClipboard.h
new file mode 100644
index 0000000000..b0afb9ee40
--- /dev/null
+++ b/widget/windows/nsClipboard.h
@@ -0,0 +1,113 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsClipboard_h__
+#define nsClipboard_h__
+
+#include "nsBaseClipboard.h"
+#include "nsIObserver.h"
+#include "nsIURI.h"
+
+#include <ole2.h>
+#include <windows.h>
+
+class nsITransferable;
+class nsIWidget;
+class nsIFile;
+struct IDataObject;
+
+/**
+ * Native Win32 Clipboard wrapper
+ */
+
+class nsClipboard : public nsBaseClipboard, public nsIObserver {
+  virtual ~nsClipboard();
+
+ public:
+  nsClipboard();
+
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // nsIObserver
+  NS_DECL_NSIOBSERVER
+
+  // Internal Native Routines
+  enum class MightNeedToFlush : bool { No, Yes };
+  static nsresult CreateNativeDataObject(nsITransferable* aTransferable,
+                                         IDataObject** aDataObj, nsIURI* aUri,
+                                         MightNeedToFlush* = nullptr);
+  static nsresult SetupNativeDataObject(nsITransferable* aTransferable,
+                                        IDataObject* aDataObj,
+                                        MightNeedToFlush* = nullptr);
+  static nsresult GetDataFromDataObject(IDataObject* aDataObject, UINT anIndex,
+                                        nsIWidget* aWindow,
+                                        nsITransferable* aTransferable);
+  static nsresult GetNativeDataOffClipboard(nsIWidget* aWindow, UINT aIndex,
+                                            UINT aFormat, void** aData,
+                                            uint32_t* aLen);
+  static nsresult GetNativeDataOffClipboard(IDataObject* aDataObject,
+                                            UINT aIndex, UINT aFormat,
+                                            const char* aMIMEImageFormat,
+                                            void** aData, uint32_t* aLen);
+  static nsresult GetGlobalData(HGLOBAL aHGBL, void** aData, uint32_t* aLen);
+
+  // This function returns the internal Windows clipboard format identifier
+  // for a given Mime string. The default is to map kHTMLMime ("text/html")
+  // to the clipboard format CF_HTML ("HTLM Format"), but it can also be
+  // registered as clipboard format "text/html" to support previous versions
+  // of Gecko.
+  static UINT GetFormat(const char* aMimeStr, bool aMapHTMLMime = true);
+
+  static UINT GetClipboardFileDescriptorFormatA();
+  static UINT GetClipboardFileDescriptorFormatW();
+  static UINT GetHtmlClipboardFormat();
+  static UINT GetCustomClipboardFormat();
+
+ protected:
+  // @param aDataObject must be non-nullptr.
+  static HRESULT FillSTGMedium(IDataObject* aDataObject, UINT aFormat,
+                               LPFORMATETC pFE, LPSTGMEDIUM pSTM, DWORD aTymed);
+
+  // Implement the native clipboard behavior.
+  NS_IMETHOD SetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) override;
+  NS_IMETHOD GetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) override;
+  nsresult EmptyNativeClipboardData(int32_t aWhichClipboard) override;
+  mozilla::Result<int32_t, nsresult> GetNativeClipboardSequenceNumber(
+      int32_t aWhichClipboard) override;
+  mozilla::Result<bool, nsresult> HasNativeClipboardDataMatchingFlavors(
+      const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) override;
+
+  static bool IsInternetShortcut(const nsAString& inFileName);
+  static bool FindURLFromLocalFile(IDataObject* inDataObject, UINT inIndex,
+                                   void** outData, uint32_t* outDataLen);
+  static bool FindURLFromNativeURL(IDataObject* inDataObject, UINT inIndex,
+                                   void** outData, uint32_t* outDataLen);
+  static bool FindUnicodeFromPlainText(IDataObject* inDataObject, UINT inIndex,
+                                       void** outData, uint32_t* outDataLen);
+  static bool FindPlatformHTML(IDataObject* inDataObject, UINT inIndex,
+                               void** outData, uint32_t* outStartOfData,
+                               uint32_t* outDataLen);
+
+  static void ResolveShortcut(nsIFile* inFileName, nsACString& outURL);
+  static nsresult GetTempFilePath(const nsAString& aFileName,
+                                  nsAString& aFilePath);
+  static nsresult SaveStorageOrStream(IDataObject* aDataObject, UINT aIndex,
+                                      const nsAString& aFileName);
+
+  nsIWidget* mWindow;
+};
+
+#define SET_FORMATETC(fe, cf, td, asp, li, med) \
+  {                                             \
+    (fe).cfFormat = cf;                         \
+    (fe).ptd = td;                              \
+    (fe).dwAspect = asp;                        \
+    (fe).lindex = li;                           \
+    (fe).tymed = med;                           \
+  }
+
+#endif  // nsClipboard_h__
diff --git a/widget/windows/nsColorPicker.cpp b/widget/windows/nsColorPicker.cpp
new file mode 100644
index 0000000000..5074b620f5
--- /dev/null
+++ b/widget/windows/nsColorPicker.cpp
@@ -0,0 +1,202 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsColorPicker.h"
+
+#include <shlwapi.h>
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/AutoRestore.h"
+#include "nsIWidget.h"
+#include "nsString.h"
+#include "WidgetUtils.h"
+#include "WinUtils.h"
+#include "nsPIDOMWindow.h"
+
+using namespace mozilla::widget;
+
+namespace {
+static DWORD ColorStringToRGB(const nsAString& aColor) {
+  DWORD result = 0;
+
+  for (uint32_t i = 1; i < aColor.Length(); ++i) {
+    result *= 16;
+
+    char16_t c = aColor[i];
+    if (c >= '0' && c <= '9') {
+      result += c - '0';
+    } else if (c >= 'a' && c <= 'f') {
+      result += 10 + (c - 'a');
+    } else {
+      result += 10 + (c - 'A');
+    }
+  }
+
+  DWORD r = result & 0x00FF0000;
+  DWORD g = result & 0x0000FF00;
+  DWORD b = result & 0x000000FF;
+
+  r = r >> 16;
+  b = b << 16;
+
+  result = r | g | b;
+
+  return result;
+}
+
+static nsString ToHexString(BYTE n) {
+  nsString result;
+  if (n <= 0x0F) {
+    result.Append('0');
+  }
+  result.AppendInt(n, 16);
+  return result;
+}
+
+static void BGRIntToRGBString(DWORD color, nsAString& aResult) {
+  BYTE r = GetRValue(color);
+  BYTE g = GetGValue(color);
+  BYTE b = GetBValue(color);
+
+  aResult.Assign('#');
+  aResult.Append(ToHexString(r));
+  aResult.Append(ToHexString(g));
+  aResult.Append(ToHexString(b));
+}
+}  // namespace
+
+static AsyncColorChooser* gColorChooser;
+
+AsyncColorChooser::AsyncColorChooser(COLORREF aInitialColor,
+                                     const nsTArray<nsString>& aDefaultColors,
+                                     nsIWidget* aParentWidget,
+                                     nsIColorPickerShownCallback* aCallback)
+    : mozilla::Runnable("AsyncColorChooser"),
+      mInitialColor(aInitialColor),
+      mDefaultColors(aDefaultColors.Clone()),
+      mColor(aInitialColor),
+      mParentWidget(aParentWidget),
+      mCallback(aCallback) {}
+
+NS_IMETHODIMP
+AsyncColorChooser::Run() {
+  MOZ_ASSERT(NS_IsMainThread(),
+             "Color pickers can only be opened from main thread currently");
+
+  // Allow only one color picker to be opened at a time, to workaround bug
+  // 944737
+  if (!gColorChooser) {
+    mozilla::AutoRestore<AsyncColorChooser*> restoreColorChooser(gColorChooser);
+    gColorChooser = this;
+
+    ScopedRtlShimWindow shim(mParentWidget.get());
+
+    COLORREF customColors[16];
+    for (size_t i = 0; i < mozilla::ArrayLength(customColors); i++) {
+      if (i < mDefaultColors.Length()) {
+        customColors[i] = ColorStringToRGB(mDefaultColors[i]);
+      } else {
+        customColors[i] = 0x00FFFFFF;
+      }
+    }
+
+    CHOOSECOLOR options;
+    options.lStructSize = sizeof(options);
+    options.hwndOwner = shim.get();
+    options.Flags = CC_RGBINIT | CC_FULLOPEN | CC_ENABLEHOOK;
+    options.rgbResult = mInitialColor;
+    options.lpCustColors = customColors;
+    options.lpfnHook = HookProc;
+
+    mColor = ChooseColor(&options) ? options.rgbResult : mInitialColor;
+  } else {
+    NS_WARNING(
+        "Currently, it's not possible to open more than one color "
+        "picker at a time");
+    mColor = mInitialColor;
+  }
+
+  if (mCallback) {
+    nsAutoString colorStr;
+    BGRIntToRGBString(mColor, colorStr);
+    mCallback->Done(colorStr);
+  }
+
+  return NS_OK;
+}
+
+void AsyncColorChooser::Update(COLORREF aColor) {
+  if (mColor != aColor) {
+    mColor = aColor;
+
+    nsAutoString colorStr;
+    BGRIntToRGBString(mColor, colorStr);
+    mCallback->Update(colorStr);
+  }
+}
+
+/* static */ UINT_PTR CALLBACK AsyncColorChooser::HookProc(HWND aDialog,
+                                                           UINT aMsg,
+                                                           WPARAM aWParam,
+                                                           LPARAM aLParam) {
+  if (!gColorChooser) {
+    return 0;
+  }
+
+  if (aMsg == WM_INITDIALOG) {
+    // "The default dialog box procedure processes the WM_INITDIALOG message
+    // before passing it to the hook procedure.
+    // For all other messages, the hook procedure receives the message first."
+    // https://docs.microsoft.com/en-us/windows/win32/api/commdlg/nc-commdlg-lpcchookproc
+    // "The dialog box procedure should return TRUE to direct the system to
+    // set the keyboard focus to the control specified by wParam."
+    // https://docs.microsoft.com/en-us/windows/win32/dlgbox/wm-initdialog
+    return 1;
+  }
+
+  if (aMsg == WM_CTLCOLORSTATIC) {
+    // The color picker does not expose a proper way to retrieve the current
+    // color, so we need to obtain it from the static control displaying the
+    // current color instead.
+    const int kCurrentColorBoxID = 709;
+    if ((HWND)aLParam == GetDlgItem(aDialog, kCurrentColorBoxID)) {
+      gColorChooser->Update(GetPixel((HDC)aWParam, 0, 0));
+    }
+  }
+
+  // Let the default dialog box procedure processes the message.
+  return 0;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// nsIColorPicker
+
+nsColorPicker::nsColorPicker() {}
+
+nsColorPicker::~nsColorPicker() {}
+
+NS_IMPL_ISUPPORTS(nsColorPicker, nsIColorPicker)
+
+NS_IMETHODIMP
+nsColorPicker::Init(mozIDOMWindowProxy* parent, const nsAString& title,
+                    const nsAString& aInitialColor,
+                    const nsTArray<nsString>& aDefaultColors) {
+  MOZ_ASSERT(parent,
+             "Null parent passed to colorpicker, no color picker for you!");
+  mParentWidget =
+      WidgetUtils::DOMWindowToWidget(nsPIDOMWindowOuter::From(parent));
+  mInitialColor = ColorStringToRGB(aInitialColor);
+  mDefaultColors.Assign(aDefaultColors);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsColorPicker::Open(nsIColorPickerShownCallback* aCallback) {
+  NS_ENSURE_ARG(aCallback);
+  nsCOMPtr<nsIRunnable> event = new AsyncColorChooser(
+      mInitialColor, mDefaultColors, mParentWidget, aCallback);
+  return NS_DispatchToMainThread(event);
+}
diff --git a/widget/windows/nsColorPicker.h b/widget/windows/nsColorPicker.h
new file mode 100644
index 0000000000..ff34b9bd48
--- /dev/null
+++ b/widget/windows/nsColorPicker.h
@@ -0,0 +1,55 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsColorPicker_h__
+#define nsColorPicker_h__
+
+#include <windows.h>
+#include <commdlg.h>
+
+#include "nsCOMPtr.h"
+#include "nsIColorPicker.h"
+#include "nsThreadUtils.h"
+
+class nsIWidget;
+
+class AsyncColorChooser : public mozilla::Runnable {
+ public:
+  AsyncColorChooser(COLORREF aInitialColor,
+                    const nsTArray<nsString>& aDefaultColors,
+                    nsIWidget* aParentWidget,
+                    nsIColorPickerShownCallback* aCallback);
+  NS_IMETHOD Run() override;
+
+ private:
+  void Update(COLORREF aColor);
+
+  static UINT_PTR CALLBACK HookProc(HWND aDialog, UINT aMsg, WPARAM aWParam,
+                                    LPARAM aLParam);
+
+  COLORREF mInitialColor;
+  nsTArray<nsString> mDefaultColors;
+  COLORREF mColor;
+  nsCOMPtr<nsIWidget> mParentWidget;
+  nsCOMPtr<nsIColorPickerShownCallback> mCallback;
+};
+
+class nsColorPicker : public nsIColorPicker {
+  virtual ~nsColorPicker();
+
+ public:
+  nsColorPicker();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSICOLORPICKER
+
+ private:
+  COLORREF mInitialColor;
+  nsTArray<nsString> mDefaultColors;
+  nsCOMPtr<nsIWidget> mParentWidget;
+};
+
+#endif  // nsColorPicker_h__
diff --git a/widget/windows/nsDataObj.cpp b/widget/windows/nsDataObj.cpp
new file mode 100644
index 0000000000..88a2a2ad09
--- /dev/null
+++ b/widget/windows/nsDataObj.cpp
@@ -0,0 +1,2276 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/TextUtils.h"
+
+#include <ole2.h>
+#include <shlobj.h>
+
+#include "nsComponentManagerUtils.h"
+#include "nsDataObj.h"
+#include "nsArrayUtils.h"
+#include "nsClipboard.h"
+#include "nsReadableUtils.h"
+#include "nsICookieJarSettings.h"
+#include "nsIHttpChannel.h"
+#include "nsISupportsPrimitives.h"
+#include "nsITransferable.h"
+#include "IEnumFE.h"
+#include "nsPrimitiveHelpers.h"
+#include "nsString.h"
+#include "nsCRT.h"
+#include "nsPrintfCString.h"
+#include "nsIStringBundle.h"
+#include "nsEscape.h"
+#include "nsIURL.h"
+#include "nsNetUtil.h"
+#include "mozilla/Components.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "mozilla/Unused.h"
+#include "nsProxyRelease.h"
+#include "nsIObserverService.h"
+#include "nsIOutputStream.h"
+#include "nscore.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsITimer.h"
+#include "nsThreadUtils.h"
+#include "mozilla/Preferences.h"
+#include "nsContentUtils.h"
+#include "nsIPrincipal.h"
+#include "nsNativeCharsetUtils.h"
+#include "nsMimeTypes.h"
+#include "nsIMIMEService.h"
+#include "imgIEncoder.h"
+#include "imgITools.h"
+#include "WinUtils.h"
+#include "nsLocalFile.h"
+
+#include "mozilla/LazyIdleThread.h"
+#include <algorithm>
+
+using namespace mozilla;
+using namespace mozilla::glue;
+using namespace mozilla::widget;
+
+#define BFH_LENGTH 14
+#define DEFAULT_THREAD_TIMEOUT_MS 30000
+
+//-----------------------------------------------------------------------------
+// CStreamBase implementation
+nsDataObj::CStreamBase::CStreamBase() : mStreamRead(0) {}
+
+//-----------------------------------------------------------------------------
+nsDataObj::CStreamBase::~CStreamBase() {}
+
+NS_IMPL_ISUPPORTS(nsDataObj::CStream, nsIStreamListener)
+
+//-----------------------------------------------------------------------------
+// CStream implementation
+nsDataObj::CStream::CStream() : mChannelRead(false) {}
+
+//-----------------------------------------------------------------------------
+nsDataObj::CStream::~CStream() {}
+
+//-----------------------------------------------------------------------------
+// helper - initializes the stream
+nsresult nsDataObj::CStream::Init(nsIURI* pSourceURI,
+                                  nsContentPolicyType aContentPolicyType,
+                                  nsIPrincipal* aRequestingPrincipal,
+                                  nsICookieJarSettings* aCookieJarSettings,
+                                  nsIReferrerInfo* aReferrerInfo) {
+  // we can not create a channel without a requestingPrincipal
+  if (!aRequestingPrincipal) {
+    return NS_ERROR_FAILURE;
+  }
+  nsresult rv;
+  rv = NS_NewChannel(getter_AddRefs(mChannel), pSourceURI, aRequestingPrincipal,
+                     nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_INHERITS_SEC_CONTEXT,
+                     aContentPolicyType, aCookieJarSettings,
+                     nullptr,  // PerformanceStorage
+                     nullptr,  // loadGroup
+                     nullptr,  // aCallbacks
+                     nsIRequest::LOAD_FROM_CACHE);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(mChannel)) {
+    rv = httpChannel->SetReferrerInfo(aReferrerInfo);
+    Unused << NS_WARN_IF(NS_FAILED(rv));
+  }
+
+  rv = mChannel->AsyncOpen(this);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// IUnknown's QueryInterface, nsISupport's AddRef and Release are shared by
+// IUnknown and nsIStreamListener.
+STDMETHODIMP nsDataObj::CStream::QueryInterface(REFIID refiid,
+                                                void** ppvResult) {
+  *ppvResult = nullptr;
+  if (IID_IUnknown == refiid || refiid == IID_IStream)
+
+  {
+    *ppvResult = this;
+  }
+
+  if (nullptr != *ppvResult) {
+    ((LPUNKNOWN)*ppvResult)->AddRef();
+    return S_OK;
+  }
+
+  return E_NOINTERFACE;
+}
+
+// nsIStreamListener implementation
+NS_IMETHODIMP
+nsDataObj::CStream::OnDataAvailable(
+    nsIRequest* aRequest, nsIInputStream* aInputStream,
+    uint64_t aOffset,  // offset within the stream
+    uint32_t aCount)   // bytes available on this call
+{
+  // If we've been asked to read zero bytes, call `Read` once, just to ensure
+  // any side-effects take place, and return immediately.
+  if (aCount == 0) {
+    char buffer[1] = {0};
+    uint32_t bytesReadByCall = 0;
+    nsresult rv = aInputStream->Read(buffer, 0, &bytesReadByCall);
+    MOZ_ASSERT(bytesReadByCall == 0);
+    return rv;
+  }
+
+  // Extend the write buffer for the incoming data.
+  size_t oldLength = mChannelData.Length();
+  char* buffer =
+      reinterpret_cast<char*>(mChannelData.AppendElements(aCount, fallible));
+  if (!buffer) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  MOZ_ASSERT(mChannelData.Length() == (aOffset + aCount),
+             "stream length mismatch w/write buffer");
+
+  // Read() may not return aCount on a single call, so loop until we've
+  // accumulated all the data OnDataAvailable has promised.
+  uint32_t bytesRead = 0;
+  while (bytesRead < aCount) {
+    uint32_t bytesReadByCall = 0;
+    nsresult rv = aInputStream->Read(buffer + bytesRead, aCount - bytesRead,
+                                     &bytesReadByCall);
+    bytesRead += bytesReadByCall;
+
+    if (bytesReadByCall == 0) {
+      // A `bytesReadByCall` of zero indicates EOF without failure... but we
+      // were promised `aCount` elements and haven't gotten them. Return a
+      // generic failure.
+      rv = NS_ERROR_FAILURE;
+    }
+
+    if (NS_FAILED(rv)) {
+      // Drop any trailing uninitialized elements before erroring out.
+      mChannelData.RemoveElementsAt(oldLength + bytesRead, aCount - bytesRead);
+      return rv;
+    }
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDataObj::CStream::OnStartRequest(nsIRequest* aRequest) {
+  mChannelResult = NS_OK;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsDataObj::CStream::OnStopRequest(nsIRequest* aRequest,
+                                                nsresult aStatusCode) {
+  mChannelRead = true;
+  mChannelResult = aStatusCode;
+  return NS_OK;
+}
+
+// Pumps thread messages while waiting for the async listener operation to
+// complete. Failing this call will fail the stream incall from Windows
+// and cancel the operation.
+nsresult nsDataObj::CStream::WaitForCompletion() {
+  // We are guaranteed OnStopRequest will get called, so this should be ok.
+  SpinEventLoopUntil("widget:nsDataObj::CStream::WaitForCompletion"_ns,
+                     [&]() { return mChannelRead; });
+
+  if (!mChannelData.Length()) mChannelResult = NS_ERROR_FAILURE;
+
+  return mChannelResult;
+}
+
+//-----------------------------------------------------------------------------
+// IStream
+STDMETHODIMP nsDataObj::CStreamBase::Clone(IStream** ppStream) {
+  return E_NOTIMPL;
+}
+
+//-----------------------------------------------------------------------------
+STDMETHODIMP nsDataObj::CStreamBase::Commit(DWORD dwFrags) { return E_NOTIMPL; }
+
+//-----------------------------------------------------------------------------
+STDMETHODIMP nsDataObj::CStreamBase::CopyTo(IStream* pDestStream,
+                                            ULARGE_INTEGER nBytesToCopy,
+                                            ULARGE_INTEGER* nBytesRead,
+                                            ULARGE_INTEGER* nBytesWritten) {
+  return E_NOTIMPL;
+}
+
+//-----------------------------------------------------------------------------
+STDMETHODIMP nsDataObj::CStreamBase::LockRegion(ULARGE_INTEGER nStart,
+                                                ULARGE_INTEGER nBytes,
+                                                DWORD dwFlags) {
+  return E_NOTIMPL;
+}
+
+//-----------------------------------------------------------------------------
+STDMETHODIMP nsDataObj::CStream::Read(void* pvBuffer, ULONG nBytesToRead,
+                                      ULONG* nBytesRead) {
+  // Wait for the write into our buffer to complete via the stream listener.
+  // We can't respond to this by saying "call us back later".
+  if (NS_FAILED(WaitForCompletion())) return E_FAIL;
+
+  // Bytes left for Windows to read out of our buffer
+  ULONG bytesLeft = mChannelData.Length() - mStreamRead;
+  // Let Windows know what we will hand back, usually this is the entire buffer
+  *nBytesRead = std::min(bytesLeft, nBytesToRead);
+  // Copy the buffer data over
+  memcpy(pvBuffer, ((char*)mChannelData.Elements() + mStreamRead), *nBytesRead);
+  // Update our bytes read tracking
+  mStreamRead += *nBytesRead;
+  return S_OK;
+}
+
+//-----------------------------------------------------------------------------
+STDMETHODIMP nsDataObj::CStreamBase::Revert(void) { return E_NOTIMPL; }
+
+//-----------------------------------------------------------------------------
+STDMETHODIMP nsDataObj::CStreamBase::Seek(LARGE_INTEGER nMove, DWORD dwOrigin,
+                                          ULARGE_INTEGER* nNewPos) {
+  if (nNewPos == nullptr) return STG_E_INVALIDPOINTER;
+
+  if (nMove.LowPart == 0 && nMove.HighPart == 0 &&
+      (dwOrigin == STREAM_SEEK_SET || dwOrigin == STREAM_SEEK_CUR)) {
+    nNewPos->LowPart = 0;
+    nNewPos->HighPart = 0;
+    return S_OK;
+  }
+
+  return E_NOTIMPL;
+}
+
+//-----------------------------------------------------------------------------
+STDMETHODIMP nsDataObj::CStreamBase::SetSize(ULARGE_INTEGER nNewSize) {
+  return E_NOTIMPL;
+}
+
+//-----------------------------------------------------------------------------
+STDMETHODIMP nsDataObj::CStream::Stat(STATSTG* statstg, DWORD dwFlags) {
+  if (statstg == nullptr) return STG_E_INVALIDPOINTER;
+
+  if (!mChannel || NS_FAILED(WaitForCompletion())) return E_FAIL;
+
+  memset((void*)statstg, 0, sizeof(STATSTG));
+
+  if (dwFlags != STATFLAG_NONAME) {
+    nsCOMPtr<nsIURI> sourceURI;
+    if (NS_FAILED(mChannel->GetURI(getter_AddRefs(sourceURI)))) {
+      return E_FAIL;
+    }
+
+    nsAutoCString strFileName;
+    nsCOMPtr<nsIURL> sourceURL = do_QueryInterface(sourceURI);
+    sourceURL->GetFileName(strFileName);
+
+    if (strFileName.IsEmpty()) return E_FAIL;
+
+    NS_UnescapeURL(strFileName);
+    NS_ConvertUTF8toUTF16 wideFileName(strFileName);
+
+    uint32_t nMaxNameLength = (wideFileName.Length() * 2) + 2;
+    void* retBuf = CoTaskMemAlloc(nMaxNameLength);  // freed by caller
+    if (!retBuf) return STG_E_INSUFFICIENTMEMORY;
+
+    ZeroMemory(retBuf, nMaxNameLength);
+    memcpy(retBuf, wideFileName.get(), wideFileName.Length() * 2);
+    statstg->pwcsName = (LPOLESTR)retBuf;
+  }
+
+  SYSTEMTIME st;
+
+  statstg->type = STGTY_STREAM;
+
+  GetSystemTime(&st);
+  SystemTimeToFileTime((const SYSTEMTIME*)&st, (LPFILETIME)&statstg->mtime);
+  statstg->ctime = statstg->atime = statstg->mtime;
+
+  statstg->cbSize.QuadPart = mChannelData.Length();
+  statstg->grfMode = STGM_READ;
+  statstg->grfLocksSupported = LOCK_ONLYONCE;
+  statstg->clsid = CLSID_NULL;
+
+  return S_OK;
+}
+
+//-----------------------------------------------------------------------------
+STDMETHODIMP nsDataObj::CStreamBase::UnlockRegion(ULARGE_INTEGER nStart,
+                                                  ULARGE_INTEGER nBytes,
+                                                  DWORD dwFlags) {
+  return E_NOTIMPL;
+}
+
+//-----------------------------------------------------------------------------
+STDMETHODIMP nsDataObj::CStreamBase::Write(const void* pvBuffer,
+                                           ULONG nBytesToRead,
+                                           ULONG* nBytesRead) {
+  return E_NOTIMPL;
+}
+
+//-----------------------------------------------------------------------------
+HRESULT nsDataObj::CreateStream(IStream** outStream) {
+  NS_ENSURE_TRUE(outStream, E_INVALIDARG);
+
+  nsresult rv = NS_ERROR_FAILURE;
+  nsAutoString wideFileName;
+  nsCOMPtr<nsIURI> sourceURI;
+  HRESULT res;
+
+  res = GetDownloadDetails(getter_AddRefs(sourceURI), wideFileName);
+  if (FAILED(res)) return res;
+
+  nsDataObj::CStream* pStream = new nsDataObj::CStream();
+  NS_ENSURE_TRUE(pStream, E_OUTOFMEMORY);
+
+  pStream->AddRef();
+
+  // query the requestingPrincipal from the transferable and add it to the new
+  // channel
+  nsCOMPtr<nsIPrincipal> requestingPrincipal =
+      mTransferable->GetRequestingPrincipal();
+  MOZ_ASSERT(requestingPrincipal, "can not create channel without a principal");
+
+  // Note that the cookieJarSettings could be null if the data object is for the
+  // image copy. We will fix this in Bug 1690532.
+  nsCOMPtr<nsICookieJarSettings> cookieJarSettings =
+      mTransferable->GetCookieJarSettings();
+
+  // The referrer is optional.
+  nsCOMPtr<nsIReferrerInfo> referrerInfo = mTransferable->GetReferrerInfo();
+
+  nsContentPolicyType contentPolicyType = mTransferable->GetContentPolicyType();
+  rv = pStream->Init(sourceURI, contentPolicyType, requestingPrincipal,
+                     cookieJarSettings, referrerInfo);
+  if (NS_FAILED(rv)) {
+    pStream->Release();
+    return E_FAIL;
+  }
+  *outStream = pStream;
+
+  return S_OK;
+}
+
+//-----------------------------------------------------------------------------
+// AutoCloseEvent implementation
+nsDataObj::AutoCloseEvent::AutoCloseEvent()
+    : mEvent(::CreateEventW(nullptr, TRUE, FALSE, nullptr)) {}
+
+bool nsDataObj::AutoCloseEvent::IsInited() const { return !!mEvent; }
+
+void nsDataObj::AutoCloseEvent::Signal() const { ::SetEvent(mEvent); }
+
+DWORD nsDataObj::AutoCloseEvent::Wait(DWORD aMillisec) const {
+  return ::WaitForSingleObject(mEvent, aMillisec);
+}
+
+//-----------------------------------------------------------------------------
+// AutoSetEvent implementation
+nsDataObj::AutoSetEvent::AutoSetEvent(NotNull<AutoCloseEvent*> aEvent)
+    : mEvent(aEvent) {}
+
+nsDataObj::AutoSetEvent::~AutoSetEvent() { Signal(); }
+
+void nsDataObj::AutoSetEvent::Signal() const { mEvent->Signal(); }
+
+bool nsDataObj::AutoSetEvent::IsWaiting() const {
+  return mEvent->Wait(0) == WAIT_TIMEOUT;
+}
+
+//-----------------------------------------------------------------------------
+// CMemStream implementation
+Win32SRWLock nsDataObj::CMemStream::mLock;
+
+//-----------------------------------------------------------------------------
+nsDataObj::CMemStream::CMemStream(nsHGLOBAL aGlobalMem, uint32_t aTotalLength,
+                                  already_AddRefed<AutoCloseEvent> aEvent)
+    : mGlobalMem(aGlobalMem), mEvent(aEvent), mTotalLength(aTotalLength) {
+  ::CoCreateFreeThreadedMarshaler(this, getter_AddRefs(mMarshaler));
+}
+
+//-----------------------------------------------------------------------------
+nsDataObj::CMemStream::~CMemStream() {}
+
+//-----------------------------------------------------------------------------
+// IUnknown
+STDMETHODIMP nsDataObj::CMemStream::QueryInterface(REFIID refiid,
+                                                   void** ppvResult) {
+  *ppvResult = nullptr;
+  if (refiid == IID_IUnknown || refiid == IID_IStream ||
+      refiid == IID_IAgileObject) {
+    *ppvResult = this;
+  } else if (refiid == IID_IMarshal && mMarshaler) {
+    return mMarshaler->QueryInterface(refiid, ppvResult);
+  }
+
+  if (nullptr != *ppvResult) {
+    ((LPUNKNOWN)*ppvResult)->AddRef();
+    return S_OK;
+  }
+
+  return E_NOINTERFACE;
+}
+
+void nsDataObj::CMemStream::WaitForCompletion() {
+  if (!mEvent) {
+    // We are not waiting for obtaining the icon cache.
+    return;
+  }
+  if (!NS_IsMainThread()) {
+    mEvent->Wait(INFINITE);
+  } else {
+    // We should not block the main thread.
+    mEvent->Signal();
+  }
+  // mEvent will always be in the signaled state here.
+}
+
+//-----------------------------------------------------------------------------
+// IStream
+STDMETHODIMP nsDataObj::CMemStream::Read(void* pvBuffer, ULONG nBytesToRead,
+                                         ULONG* nBytesRead) {
+  // Wait until the event is signaled.
+  WaitForCompletion();
+
+  AutoExclusiveLock lock(mLock);
+  char* contents = reinterpret_cast<char*>(GlobalLock(mGlobalMem.get()));
+  if (!contents) {
+    return E_OUTOFMEMORY;
+  }
+
+  // Bytes left for Windows to read out of our buffer
+  ULONG bytesLeft = mTotalLength - mStreamRead;
+  // Let Windows know what we will hand back, usually this is the entire buffer
+  *nBytesRead = std::min(bytesLeft, nBytesToRead);
+  // Copy the buffer data over
+  memcpy(pvBuffer, contents + mStreamRead, *nBytesRead);
+  // Update our bytes read tracking
+  mStreamRead += *nBytesRead;
+
+  GlobalUnlock(mGlobalMem.get());
+  return S_OK;
+}
+
+//-----------------------------------------------------------------------------
+STDMETHODIMP nsDataObj::CMemStream::Stat(STATSTG* statstg, DWORD dwFlags) {
+  if (statstg == nullptr) return STG_E_INVALIDPOINTER;
+
+  memset((void*)statstg, 0, sizeof(STATSTG));
+
+  if (dwFlags != STATFLAG_NONAME) {
+    constexpr size_t kMaxNameLength = sizeof(wchar_t);
+    void* retBuf = CoTaskMemAlloc(kMaxNameLength);  // freed by caller
+    if (!retBuf) return STG_E_INSUFFICIENTMEMORY;
+
+    ZeroMemory(retBuf, kMaxNameLength);
+    statstg->pwcsName = (LPOLESTR)retBuf;
+  }
+
+  SYSTEMTIME st;
+
+  statstg->type = STGTY_STREAM;
+
+  GetSystemTime(&st);
+  SystemTimeToFileTime((const SYSTEMTIME*)&st, (LPFILETIME)&statstg->mtime);
+  statstg->ctime = statstg->atime = statstg->mtime;
+
+  statstg->cbSize.QuadPart = mTotalLength;
+  statstg->grfMode = STGM_READ;
+  statstg->grfLocksSupported = LOCK_ONLYONCE;
+  statstg->clsid = CLSID_NULL;
+
+  return S_OK;
+}
+
+/*
+ * Class nsDataObj
+ */
+
+//-----------------------------------------------------
+// construction
+//-----------------------------------------------------
+nsDataObj::nsDataObj(nsIURI* uri)
+    : m_cRef(0),
+      mTransferable(nullptr),
+      mIsAsyncMode(FALSE),
+      mIsInOperation(FALSE) {
+  mIOThread = new LazyIdleThread(DEFAULT_THREAD_TIMEOUT_MS, "nsDataObj",
+                                 LazyIdleThread::ManualShutdown);
+  m_enumFE = new CEnumFormatEtc();
+  m_enumFE->AddRef();
+
+  if (uri) {
+    // A URI was obtained, so pass this through to the DataObject
+    // so it can create a SourceURL for CF_HTML flavour
+    uri->GetSpec(mSourceURL);
+  }
+}
+//-----------------------------------------------------
+// destruction
+//-----------------------------------------------------
+nsDataObj::~nsDataObj() {
+  NS_IF_RELEASE(mTransferable);
+
+  mDataFlavors.Clear();
+
+  m_enumFE->Release();
+
+  // Free arbitrary system formats
+  for (uint32_t idx = 0; idx < mDataEntryList.Length(); idx++) {
+    CoTaskMemFree(mDataEntryList[idx]->fe.ptd);
+    ReleaseStgMedium(&mDataEntryList[idx]->stgm);
+    CoTaskMemFree(mDataEntryList[idx]);
+  }
+}
+
+//-----------------------------------------------------
+// IUnknown interface methods - see inknown.h for documentation
+//-----------------------------------------------------
+STDMETHODIMP nsDataObj::QueryInterface(REFIID riid, void** ppv) {
+  *ppv = nullptr;
+
+  if ((IID_IUnknown == riid) || (IID_IDataObject == riid)) {
+    *ppv = this;
+    AddRef();
+    return S_OK;
+  } else if (IID_IDataObjectAsyncCapability == riid) {
+    *ppv = static_cast<IDataObjectAsyncCapability*>(this);
+    AddRef();
+    return S_OK;
+  }
+
+  return E_NOINTERFACE;
+}
+
+//-----------------------------------------------------
+STDMETHODIMP_(ULONG) nsDataObj::AddRef() {
+  ++m_cRef;
+  NS_LOG_ADDREF(this, m_cRef, "nsDataObj", sizeof(*this));
+
+  // When the first reference is taken, hold our own internal reference.
+  if (m_cRef == 1) {
+    mKeepAlive = this;
+  }
+
+  return m_cRef;
+}
+
+namespace {
+class RemoveTempFileHelper final : public nsIObserver, public nsINamed {
+ public:
+  explicit RemoveTempFileHelper(nsIFile* aTempFile) : mTempFile(aTempFile) {
+    MOZ_ASSERT(mTempFile);
+  }
+
+  // The attach method is seperate from the constructor as we may be addref-ing
+  // ourself, and we want to be sure someone has a strong reference to us.
+  void Attach() {
+    // We need to listen to both the xpcom shutdown message and our timer, and
+    // fire when the first of either of these two messages is received.
+    nsresult rv;
+    rv = NS_NewTimerWithObserver(getter_AddRefs(mTimer), this, 500,
+                                 nsITimer::TYPE_ONE_SHOT);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
+    }
+
+    nsCOMPtr<nsIObserverService> observerService =
+        do_GetService("@mozilla.org/observer-service;1");
+    if (NS_WARN_IF(!observerService)) {
+      mTimer->Cancel();
+      mTimer = nullptr;
+      return;
+    }
+    observerService->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
+  }
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+  NS_DECL_NSINAMED
+
+ private:
+  ~RemoveTempFileHelper() {
+    if (mTempFile) {
+      mTempFile->Remove(false);
+    }
+  }
+
+  nsCOMPtr<nsIFile> mTempFile;
+  nsCOMPtr<nsITimer> mTimer;
+};
+
+NS_IMPL_ISUPPORTS(RemoveTempFileHelper, nsIObserver, nsINamed);
+
+NS_IMETHODIMP
+RemoveTempFileHelper::Observe(nsISupports* aSubject, const char* aTopic,
+                              const char16_t* aData) {
+  // Let's be careful and make sure that we don't die immediately
+  RefPtr<RemoveTempFileHelper> grip = this;
+
+  // Make sure that we aren't called again by destroying references to ourself.
+  nsCOMPtr<nsIObserverService> observerService =
+      do_GetService("@mozilla.org/observer-service;1");
+  if (observerService) {
+    observerService->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID);
+  }
+
+  if (mTimer) {
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
+
+  // Remove the tempfile
+  if (mTempFile) {
+    mTempFile->Remove(false);
+    mTempFile = nullptr;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+RemoveTempFileHelper::GetName(nsACString& aName) {
+  aName.AssignLiteral("RemoveTempFileHelper");
+  return NS_OK;
+}
+}  // namespace
+
+//-----------------------------------------------------
+STDMETHODIMP_(ULONG) nsDataObj::Release() {
+  --m_cRef;
+
+  NS_LOG_RELEASE(this, m_cRef, "nsDataObj");
+
+  // If we hold the last reference, submit release of it to the main thread.
+  if (m_cRef == 1 && mKeepAlive) {
+    NS_ReleaseOnMainThread("nsDataObj release", mKeepAlive.forget(), true);
+  }
+
+  if (0 != m_cRef) return m_cRef;
+
+  // We have released our last ref on this object and need to delete the
+  // temp file. External app acting as drop target may still need to open the
+  // temp file. Addref a timer so it can delay deleting file and destroying
+  // this object.
+  if (mCachedTempFile) {
+    RefPtr<RemoveTempFileHelper> helper =
+        new RemoveTempFileHelper(mCachedTempFile);
+    mCachedTempFile = nullptr;
+    helper->Attach();
+  }
+
+  // In case the destructor ever AddRef/Releases, ensure we don't delete twice
+  // or take mKeepAlive as another reference.
+  m_cRef = 1;
+
+  delete this;
+
+  return 0;
+}
+
+//-----------------------------------------------------
+BOOL nsDataObj::FormatsMatch(const FORMATETC& source,
+                             const FORMATETC& target) const {
+  if ((source.cfFormat == target.cfFormat) &&
+      (source.dwAspect & target.dwAspect) && (source.tymed & target.tymed)) {
+    return TRUE;
+  } else {
+    return FALSE;
+  }
+}
+
+//-----------------------------------------------------
+// IDataObject methods
+//-----------------------------------------------------
+STDMETHODIMP nsDataObj::GetData(LPFORMATETC aFormat, LPSTGMEDIUM pSTM) {
+  if (!mTransferable) return DV_E_FORMATETC;
+
+  // Hold an extra reference in case we end up spinning the event loop.
+  RefPtr<nsDataObj> keepAliveDuringGetData(this);
+
+  uint32_t dfInx = 0;
+
+  static CLIPFORMAT fileDescriptorFlavorA =
+      ::RegisterClipboardFormat(CFSTR_FILEDESCRIPTORA);
+  static CLIPFORMAT fileDescriptorFlavorW =
+      ::RegisterClipboardFormat(CFSTR_FILEDESCRIPTORW);
+  static CLIPFORMAT uniformResourceLocatorA =
+      ::RegisterClipboardFormat(CFSTR_INETURLA);
+  static CLIPFORMAT uniformResourceLocatorW =
+      ::RegisterClipboardFormat(CFSTR_INETURLW);
+  static CLIPFORMAT fileFlavor = ::RegisterClipboardFormat(CFSTR_FILECONTENTS);
+  static CLIPFORMAT PreferredDropEffect =
+      ::RegisterClipboardFormat(CFSTR_PREFERREDDROPEFFECT);
+
+  // Arbitrary system formats are used for image feedback during drag
+  // and drop. We are responsible for storing these internally during
+  // drag operations.
+  LPDATAENTRY pde;
+  if (LookupArbitraryFormat(aFormat, &pde, FALSE)) {
+    return CopyMediumData(pSTM, &pde->stgm, aFormat, FALSE) ? S_OK
+                                                            : E_UNEXPECTED;
+  }
+
+  // Firefox internal formats
+  ULONG count;
+  FORMATETC fe;
+  m_enumFE->Reset();
+  while (NOERROR == m_enumFE->Next(1, &fe, &count) &&
+         dfInx < mDataFlavors.Length()) {
+    nsCString& df = mDataFlavors.ElementAt(dfInx);
+    if (FormatsMatch(fe, *aFormat)) {
+      pSTM->pUnkForRelease =
+          nullptr;  // caller is responsible for deleting this data
+      CLIPFORMAT format = aFormat->cfFormat;
+      switch (format) {
+        // Someone is asking for plain or unicode text
+        case CF_TEXT:
+        case CF_UNICODETEXT:
+          return GetText(df, *aFormat, *pSTM);
+
+        // Some 3rd party apps that receive drag and drop files from the browser
+        // window require support for this.
+        case CF_HDROP:
+          return GetFile(*aFormat, *pSTM);
+
+        // Someone is asking for an image
+        case CF_DIBV5:
+        case CF_DIB:
+          return GetDib(df, *aFormat, *pSTM);
+
+        default:
+          if (format == fileDescriptorFlavorA)
+            return GetFileDescriptor(*aFormat, *pSTM, false);
+          if (format == fileDescriptorFlavorW)
+            return GetFileDescriptor(*aFormat, *pSTM, true);
+          if (format == uniformResourceLocatorA)
+            return GetUniformResourceLocator(*aFormat, *pSTM, false);
+          if (format == uniformResourceLocatorW)
+            return GetUniformResourceLocator(*aFormat, *pSTM, true);
+          if (format == fileFlavor) return GetFileContents(*aFormat, *pSTM);
+          if (format == PreferredDropEffect)
+            return GetPreferredDropEffect(*aFormat, *pSTM);
+          // MOZ_LOG(gWindowsLog, LogLevel::Info,
+          //       ("***** nsDataObj::GetData - Unknown format %u\n", format));
+          return GetText(df, *aFormat, *pSTM);
+      }  // switch
+    }    // if
+    dfInx++;
+  }  // while
+
+  return DATA_E_FORMATETC;
+}
+
+//-----------------------------------------------------
+STDMETHODIMP nsDataObj::GetDataHere(LPFORMATETC pFE, LPSTGMEDIUM pSTM) {
+  return E_FAIL;
+}
+
+//-----------------------------------------------------
+// Other objects querying to see if we support a
+// particular format
+//-----------------------------------------------------
+STDMETHODIMP nsDataObj::QueryGetData(LPFORMATETC pFE) {
+  // Arbitrary system formats are used for image feedback during drag
+  // and drop. We are responsible for storing these internally during
+  // drag operations.
+  LPDATAENTRY pde;
+  if (LookupArbitraryFormat(pFE, &pde, FALSE)) return S_OK;
+
+  // Firefox internal formats
+  ULONG count;
+  FORMATETC fe;
+  m_enumFE->Reset();
+  while (NOERROR == m_enumFE->Next(1, &fe, &count)) {
+    if (fe.cfFormat == pFE->cfFormat) {
+      return S_OK;
+    }
+  }
+  return E_FAIL;
+}
+
+//-----------------------------------------------------
+STDMETHODIMP nsDataObj::GetCanonicalFormatEtc(LPFORMATETC pFEIn,
+                                              LPFORMATETC pFEOut) {
+  return E_NOTIMPL;
+}
+
+//-----------------------------------------------------
+STDMETHODIMP nsDataObj::SetData(LPFORMATETC aFormat, LPSTGMEDIUM aMedium,
+                                BOOL shouldRel) {
+  // Arbitrary system formats are used for image feedback during drag
+  // and drop. We are responsible for storing these internally during
+  // drag operations.
+  LPDATAENTRY pde;
+  if (LookupArbitraryFormat(aFormat, &pde, TRUE)) {
+    // Release the old data the lookup handed us for this format. This
+    // may have been set in CopyMediumData when we originally stored the
+    // data.
+    if (pde->stgm.tymed) {
+      ReleaseStgMedium(&pde->stgm);
+      memset(&pde->stgm, 0, sizeof(STGMEDIUM));
+    }
+
+    bool result = true;
+    if (shouldRel) {
+      // If shouldRel is TRUE, the data object called owns the storage medium
+      // after the call returns. Store the incoming data in our data array for
+      // release when we are destroyed. This is the common case with arbitrary
+      // data from explorer.
+      pde->stgm = *aMedium;
+    } else {
+      // Copy the incoming data into our data array. (AFAICT, this never gets
+      // called with arbitrary formats for drag images.)
+      result = CopyMediumData(&pde->stgm, aMedium, aFormat, TRUE);
+    }
+    pde->fe.tymed = pde->stgm.tymed;
+
+    return result ? S_OK : DV_E_TYMED;
+  }
+
+  if (shouldRel) ReleaseStgMedium(aMedium);
+
+  return S_OK;
+}
+
+bool nsDataObj::LookupArbitraryFormat(FORMATETC* aFormat,
+                                      LPDATAENTRY* aDataEntry,
+                                      BOOL aAddorUpdate) {
+  *aDataEntry = nullptr;
+
+  if (aFormat->ptd != nullptr) return false;
+
+  // See if it's already in our list. If so return the data entry.
+  for (uint32_t idx = 0; idx < mDataEntryList.Length(); idx++) {
+    if (mDataEntryList[idx]->fe.cfFormat == aFormat->cfFormat &&
+        mDataEntryList[idx]->fe.dwAspect == aFormat->dwAspect &&
+        mDataEntryList[idx]->fe.lindex == aFormat->lindex) {
+      if (aAddorUpdate || (mDataEntryList[idx]->fe.tymed & aFormat->tymed)) {
+        // If the caller requests we update, or if the
+        // medium type matches, return the entry.
+        *aDataEntry = mDataEntryList[idx];
+        return true;
+      } else {
+        // Medium does not match, not found.
+        return false;
+      }
+    }
+  }
+
+  if (!aAddorUpdate) return false;
+
+  // Add another entry to mDataEntryList
+  LPDATAENTRY dataEntry = (LPDATAENTRY)CoTaskMemAlloc(sizeof(DATAENTRY));
+  if (!dataEntry) return false;
+
+  dataEntry->fe = *aFormat;
+  *aDataEntry = dataEntry;
+  memset(&dataEntry->stgm, 0, sizeof(STGMEDIUM));
+
+  // Add this to our IEnumFORMATETC impl. so we can return it when
+  // it's requested.
+  m_enumFE->AddFormatEtc(aFormat);
+
+  // Store a copy internally in the arbitrary formats array.
+  mDataEntryList.AppendElement(dataEntry);
+
+  return true;
+}
+
+bool nsDataObj::CopyMediumData(STGMEDIUM* aMediumDst, STGMEDIUM* aMediumSrc,
+                               LPFORMATETC aFormat, BOOL aSetData) {
+  STGMEDIUM stgmOut = *aMediumSrc;
+
+  switch (stgmOut.tymed) {
+    case TYMED_ISTREAM:
+      stgmOut.pstm->AddRef();
+      break;
+    case TYMED_ISTORAGE:
+      stgmOut.pstg->AddRef();
+      break;
+    case TYMED_HGLOBAL:
+      if (!aMediumSrc->pUnkForRelease) {
+        if (aSetData) {
+          if (aMediumSrc->tymed != TYMED_HGLOBAL) return false;
+          stgmOut.hGlobal =
+              OleDuplicateData(aMediumSrc->hGlobal, aFormat->cfFormat, 0);
+          if (!stgmOut.hGlobal) return false;
+        } else {
+          // We are returning this data from LookupArbitraryFormat, indicate to
+          // the shell we hold it and will free it.
+          stgmOut.pUnkForRelease = static_cast<IDataObject*>(this);
+        }
+      }
+      break;
+    default:
+      return false;
+  }
+
+  if (stgmOut.pUnkForRelease) stgmOut.pUnkForRelease->AddRef();
+
+  *aMediumDst = stgmOut;
+
+  return true;
+}
+
+//-----------------------------------------------------
+STDMETHODIMP nsDataObj::EnumFormatEtc(DWORD dwDir, LPENUMFORMATETC* ppEnum) {
+  switch (dwDir) {
+    case DATADIR_GET:
+      m_enumFE->Clone(ppEnum);
+      break;
+    case DATADIR_SET:
+      // fall through
+    default:
+      *ppEnum = nullptr;
+  }  // switch
+
+  if (nullptr == *ppEnum) return E_FAIL;
+
+  (*ppEnum)->Reset();
+  // Clone already AddRefed the result so don't addref it again.
+  return NOERROR;
+}
+
+//-----------------------------------------------------
+STDMETHODIMP nsDataObj::DAdvise(LPFORMATETC pFE, DWORD dwFlags,
+                                LPADVISESINK pIAdviseSink, DWORD* pdwConn) {
+  return OLE_E_ADVISENOTSUPPORTED;
+}
+
+//-----------------------------------------------------
+STDMETHODIMP nsDataObj::DUnadvise(DWORD dwConn) {
+  return OLE_E_ADVISENOTSUPPORTED;
+}
+
+//-----------------------------------------------------
+STDMETHODIMP nsDataObj::EnumDAdvise(LPENUMSTATDATA* ppEnum) {
+  return OLE_E_ADVISENOTSUPPORTED;
+}
+
+// IDataObjectAsyncCapability methods
+STDMETHODIMP nsDataObj::EndOperation(HRESULT hResult, IBindCtx* pbcReserved,
+                                     DWORD dwEffects) {
+  mIsInOperation = FALSE;
+  return S_OK;
+}
+
+STDMETHODIMP nsDataObj::GetAsyncMode(BOOL* pfIsOpAsync) {
+  *pfIsOpAsync = mIsAsyncMode;
+
+  return S_OK;
+}
+
+STDMETHODIMP nsDataObj::InOperation(BOOL* pfInAsyncOp) {
+  *pfInAsyncOp = mIsInOperation;
+
+  return S_OK;
+}
+
+STDMETHODIMP nsDataObj::SetAsyncMode(BOOL fDoOpAsync) {
+  mIsAsyncMode = fDoOpAsync;
+  return S_OK;
+}
+
+STDMETHODIMP nsDataObj::StartOperation(IBindCtx* pbcReserved) {
+  mIsInOperation = TRUE;
+  return S_OK;
+}
+
+//
+// GetDIB
+//
+// Someone is asking for a bitmap. The data in the transferable will be a
+// straight imgIContainer, so just QI it.
+//
+HRESULT
+nsDataObj::GetDib(const nsACString& inFlavor, FORMATETC& aFormat,
+                  STGMEDIUM& aSTG) {
+  nsCOMPtr<nsISupports> genericDataWrapper;
+  if (NS_FAILED(
+          mTransferable->GetTransferData(PromiseFlatCString(inFlavor).get(),
+                                         getter_AddRefs(genericDataWrapper)))) {
+    return E_FAIL;
+  }
+
+  nsCOMPtr<imgIContainer> image = do_QueryInterface(genericDataWrapper);
+  if (!image) {
+    return E_FAIL;
+  }
+
+  nsCOMPtr<imgITools> imgTools =
+      do_CreateInstance("@mozilla.org/image/tools;1");
+
+  nsAutoString options(u"bpp=32;"_ns);
+  if (aFormat.cfFormat == CF_DIBV5) {
+    options.AppendLiteral("version=5");
+  } else {
+    options.AppendLiteral("version=3");
+  }
+
+  nsCOMPtr<nsIInputStream> inputStream;
+  nsresult rv = imgTools->EncodeImage(image, nsLiteralCString(IMAGE_BMP),
+                                      options, getter_AddRefs(inputStream));
+  if (NS_FAILED(rv) || !inputStream) {
+    return E_FAIL;
+  }
+
+  nsCOMPtr<imgIEncoder> encoder = do_QueryInterface(inputStream);
+  if (!encoder) {
+    return E_FAIL;
+  }
+
+  uint32_t size = 0;
+  rv = encoder->GetImageBufferUsed(&size);
+  if (NS_FAILED(rv) || size <= BFH_LENGTH) {
+    return E_FAIL;
+  }
+
+  char* src = nullptr;
+  rv = encoder->GetImageBuffer(&src);
+  if (NS_FAILED(rv) || !src) {
+    return E_FAIL;
+  }
+
+  // We don't want the file header.
+  src += BFH_LENGTH;
+  size -= BFH_LENGTH;
+
+  HGLOBAL glob = ::GlobalAlloc(GMEM_MOVEABLE | GMEM_ZEROINIT, size);
+  if (!glob) {
+    return E_FAIL;
+  }
+
+  char* dst = (char*)::GlobalLock(glob);
+  ::CopyMemory(dst, src, size);
+  ::GlobalUnlock(glob);
+
+  aSTG.hGlobal = glob;
+  aSTG.tymed = TYMED_HGLOBAL;
+  return S_OK;
+}
+
+//
+// GetFileDescriptor
+//
+
+HRESULT
+nsDataObj ::GetFileDescriptor(FORMATETC& aFE, STGMEDIUM& aSTG,
+                              bool aIsUnicode) {
+  HRESULT res = S_OK;
+
+  // How we handle this depends on if we're dealing with an internet
+  // shortcut, since those are done under the covers.
+  if (IsFlavourPresent(kFilePromiseMime) || IsFlavourPresent(kFileMime)) {
+    if (aIsUnicode)
+      return GetFileDescriptor_IStreamW(aFE, aSTG);
+    else
+      return GetFileDescriptor_IStreamA(aFE, aSTG);
+  } else if (IsFlavourPresent(kURLMime)) {
+    if (aIsUnicode)
+      res = GetFileDescriptorInternetShortcutW(aFE, aSTG);
+    else
+      res = GetFileDescriptorInternetShortcutA(aFE, aSTG);
+  } else
+    NS_WARNING("Not yet implemented\n");
+
+  return res;
+}  // GetFileDescriptor
+
+//
+HRESULT
+nsDataObj ::GetFileContents(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  HRESULT res = S_OK;
+
+  // How we handle this depends on if we're dealing with an internet
+  // shortcut, since those are done under the covers.
+  if (IsFlavourPresent(kFilePromiseMime) || IsFlavourPresent(kFileMime))
+    return GetFileContents_IStream(aFE, aSTG);
+  else if (IsFlavourPresent(kURLMime))
+    return GetFileContentsInternetShortcut(aFE, aSTG);
+  else
+    NS_WARNING("Not yet implemented\n");
+
+  return res;
+
+}  // GetFileContents
+
+// Ensure that the supplied name doesn't have invalid characters.
+static void ValidateFilename(nsString& aFilename, bool isShortcut) {
+  nsCOMPtr<nsIMIMEService> mimeService = do_GetService("@mozilla.org/mime;1");
+  if (NS_WARN_IF(!mimeService)) {
+    aFilename.Truncate();
+    return;
+  }
+
+  uint32_t flags = nsIMIMEService::VALIDATE_SANITIZE_ONLY;
+  if (isShortcut) {
+    flags |= nsIMIMEService::VALIDATE_ALLOW_INVALID_FILENAMES;
+  }
+
+  nsAutoString outFilename;
+  mimeService->ValidateFileNameForSaving(aFilename, EmptyCString(), flags,
+                                         outFilename);
+  aFilename = outFilename;
+}
+
+//
+// Given a unicode string, convert it to a valid local charset filename
+// and append the .url extension to be used for a shortcut file.
+// This ensures that we do not cut MBCS characters in the middle.
+//
+// It would seem that this is more functionality suited to being in nsIFile.
+//
+static bool CreateURLFilenameFromTextA(nsAutoString& aText, char* aFilename) {
+  if (aText.IsEmpty()) {
+    return false;
+  }
+  aText.AppendLiteral(".url");
+  ValidateFilename(aText, true);
+  if (aText.IsEmpty()) {
+    return false;
+  }
+
+  // ValidateFilename should already be checking the filename length, but do
+  // an extra check to verify for the local code page that the converted text
+  // doesn't go over MAX_PATH and just return false if it does.
+  char defaultChar = '_';
+  int currLen = WideCharToMultiByte(CP_ACP, WC_COMPOSITECHECK | WC_DEFAULTCHAR,
+                                    aText.get(), -1, aFilename, MAX_PATH,
+                                    &defaultChar, nullptr);
+  return currLen != 0;
+}
+
+// Wide character version of CreateURLFilenameFromTextA
+static bool CreateURLFilenameFromTextW(nsAutoString& aText,
+                                       wchar_t* aFilename) {
+  if (aText.IsEmpty()) {
+    return false;
+  }
+  aText.AppendLiteral(".url");
+  ValidateFilename(aText, true);
+  if (aText.IsEmpty() || aText.Length() >= MAX_PATH) {
+    return false;
+  }
+
+  wcscpy(&aFilename[0], aText.get());
+  return true;
+}
+
+#define PAGEINFO_PROPERTIES "chrome://navigator/locale/pageInfo.properties"
+
+static bool GetLocalizedString(const char* aName, nsAString& aString) {
+  nsCOMPtr<nsIStringBundleService> stringService =
+      mozilla::components::StringBundle::Service();
+  if (!stringService) return false;
+
+  nsCOMPtr<nsIStringBundle> stringBundle;
+  nsresult rv = stringService->CreateBundle(PAGEINFO_PROPERTIES,
+                                            getter_AddRefs(stringBundle));
+  if (NS_FAILED(rv)) return false;
+
+  rv = stringBundle->GetStringFromName(aName, aString);
+  return NS_SUCCEEDED(rv);
+}
+
+//
+// GetFileDescriptorInternetShortcut
+//
+// Create the special format for an internet shortcut and build up the data
+// structures the shell is expecting.
+//
+HRESULT
+nsDataObj ::GetFileDescriptorInternetShortcutA(FORMATETC& aFE,
+                                               STGMEDIUM& aSTG) {
+  // get the title of the shortcut
+  nsAutoString title;
+  if (NS_FAILED(ExtractShortcutTitle(title))) return E_OUTOFMEMORY;
+
+  HGLOBAL fileGroupDescHandle =
+      ::GlobalAlloc(GMEM_ZEROINIT | GMEM_SHARE, sizeof(FILEGROUPDESCRIPTORA));
+  if (!fileGroupDescHandle) return E_OUTOFMEMORY;
+
+  LPFILEGROUPDESCRIPTORA fileGroupDescA =
+      reinterpret_cast<LPFILEGROUPDESCRIPTORA>(
+          ::GlobalLock(fileGroupDescHandle));
+  if (!fileGroupDescA) {
+    ::GlobalFree(fileGroupDescHandle);
+    return E_OUTOFMEMORY;
+  }
+
+  // get a valid filename in the following order: 1) from the page title,
+  // 2) localized string for an untitled page, 3) just use "Untitled.url"
+  if (!CreateURLFilenameFromTextA(title, fileGroupDescA->fgd[0].cFileName)) {
+    nsAutoString untitled;
+    if (!GetLocalizedString("noPageTitle", untitled) ||
+        !CreateURLFilenameFromTextA(untitled,
+                                    fileGroupDescA->fgd[0].cFileName)) {
+      strcpy(fileGroupDescA->fgd[0].cFileName, "Untitled.url");
+    }
+  }
+
+  // one file in the file block
+  fileGroupDescA->cItems = 1;
+  fileGroupDescA->fgd[0].dwFlags = FD_LINKUI;
+
+  ::GlobalUnlock(fileGroupDescHandle);
+  aSTG.hGlobal = fileGroupDescHandle;
+  aSTG.tymed = TYMED_HGLOBAL;
+
+  return S_OK;
+}  // GetFileDescriptorInternetShortcutA
+
+HRESULT
+nsDataObj ::GetFileDescriptorInternetShortcutW(FORMATETC& aFE,
+                                               STGMEDIUM& aSTG) {
+  // get the title of the shortcut
+  nsAutoString title;
+  if (NS_FAILED(ExtractShortcutTitle(title))) return E_OUTOFMEMORY;
+
+  HGLOBAL fileGroupDescHandle =
+      ::GlobalAlloc(GMEM_ZEROINIT | GMEM_SHARE, sizeof(FILEGROUPDESCRIPTORW));
+  if (!fileGroupDescHandle) return E_OUTOFMEMORY;
+
+  LPFILEGROUPDESCRIPTORW fileGroupDescW =
+      reinterpret_cast<LPFILEGROUPDESCRIPTORW>(
+          ::GlobalLock(fileGroupDescHandle));
+  if (!fileGroupDescW) {
+    ::GlobalFree(fileGroupDescHandle);
+    return E_OUTOFMEMORY;
+  }
+
+  // get a valid filename in the following order: 1) from the page title,
+  // 2) localized string for an untitled page, 3) just use "Untitled.url"
+  if (!CreateURLFilenameFromTextW(title, fileGroupDescW->fgd[0].cFileName)) {
+    nsAutoString untitled;
+    if (!GetLocalizedString("noPageTitle", untitled) ||
+        !CreateURLFilenameFromTextW(untitled,
+                                    fileGroupDescW->fgd[0].cFileName)) {
+      wcscpy(fileGroupDescW->fgd[0].cFileName, L"Untitled.url");
+    }
+  }
+
+  // one file in the file block
+  fileGroupDescW->cItems = 1;
+  fileGroupDescW->fgd[0].dwFlags = FD_LINKUI;
+
+  ::GlobalUnlock(fileGroupDescHandle);
+  aSTG.hGlobal = fileGroupDescHandle;
+  aSTG.tymed = TYMED_HGLOBAL;
+
+  return S_OK;
+}  // GetFileDescriptorInternetShortcutW
+
+//
+// GetFileContentsInternetShortcut
+//
+// Create the special format for an internet shortcut and build up the data
+// structures the shell is expecting.
+//
+HRESULT
+nsDataObj ::GetFileContentsInternetShortcut(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  static const char* kShellIconPref = "browser.shell.shortcutFavicons";
+  nsAutoString url;
+  if (NS_FAILED(ExtractShortcutURL(url))) return E_OUTOFMEMORY;
+
+  nsCOMPtr<nsIURI> aUri;
+  nsresult rv = NS_NewURI(getter_AddRefs(aUri), url);
+  if (NS_FAILED(rv)) {
+    return E_FAIL;
+  }
+
+  nsAutoCString asciiUrl;
+  rv = aUri->GetAsciiSpec(asciiUrl);
+  if (NS_FAILED(rv)) {
+    return E_FAIL;
+  }
+
+  RefPtr<AutoCloseEvent> event;
+
+  const char* shortcutFormatStr;
+  int totalLen;
+  nsCString asciiPath;
+  if (!Preferences::GetBool(kShellIconPref, true)) {
+    shortcutFormatStr = "[InternetShortcut]\r\nURL=%s\r\n";
+    const int formatLen = strlen(shortcutFormatStr) - 2;  // don't include %s
+    totalLen = formatLen + asciiUrl.Length();  // don't include null character
+  } else {
+    nsCOMPtr<nsIFile> icoFile;
+
+    nsAutoString aUriHash;
+
+    event = new AutoCloseEvent();
+    if (!event->IsInited()) {
+      return E_FAIL;
+    }
+
+    RefPtr<AutoSetEvent> e = new AutoSetEvent(WrapNotNull(event));
+    mozilla::widget::FaviconHelper::ObtainCachedIconFile(
+        aUri, aUriHash, mIOThread, true,
+        NS_NewRunnableFunction(
+            "FaviconHelper::RefreshDesktop", [e = std::move(e)] {
+              if (e->IsWaiting()) {
+                // Unblock IStream:::Read.
+                e->Signal();
+              } else {
+                // We could not wait until the favicon was available. We have
+                // to refresh to refect the favicon.
+                SendNotifyMessage(HWND_BROADCAST, WM_SETTINGCHANGE,
+                                  SPI_SETNONCLIENTMETRICS, 0);
+              }
+            }));
+
+    rv = mozilla::widget::FaviconHelper::GetOutputIconPath(aUri, icoFile, true);
+    NS_ENSURE_SUCCESS(rv, E_FAIL);
+    nsString path;
+    rv = icoFile->GetPath(path);
+    NS_ENSURE_SUCCESS(rv, E_FAIL);
+
+    if (IsAsciiNullTerminated(static_cast<const char16_t*>(path.get()))) {
+      LossyCopyUTF16toASCII(path, asciiPath);
+      shortcutFormatStr =
+          "[InternetShortcut]\r\nURL=%s\r\n"
+          "IDList=\r\nHotKey=0\r\nIconFile=%s\r\n"
+          "IconIndex=0\r\n";
+    } else {
+      int len =
+          WideCharToMultiByte(CP_UTF7, 0, char16ptr_t(path.BeginReading()),
+                              path.Length(), nullptr, 0, nullptr, nullptr);
+      NS_ENSURE_TRUE(len > 0, E_FAIL);
+      asciiPath.SetLength(len);
+      WideCharToMultiByte(CP_UTF7, 0, char16ptr_t(path.BeginReading()),
+                          path.Length(), asciiPath.BeginWriting(), len, nullptr,
+                          nullptr);
+      shortcutFormatStr =
+          "[InternetShortcut]\r\nURL=%s\r\n"
+          "IDList=\r\nHotKey=0\r\nIconIndex=0\r\n"
+          "[InternetShortcut.W]\r\nIconFile=%s\r\n";
+    }
+    const int formatLen = strlen(shortcutFormatStr) - 2 * 2;  // no %s twice
+    totalLen = formatLen + asciiUrl.Length() +
+               asciiPath.Length();  // we don't want a null character on the end
+  }
+
+  // create a global memory area and build up the file contents w/in it
+  nsAutoGlobalMem globalMem(nsHGLOBAL(::GlobalAlloc(GMEM_SHARE, totalLen)));
+  if (!globalMem) return E_OUTOFMEMORY;
+
+  char* contents = reinterpret_cast<char*>(::GlobalLock(globalMem.get()));
+  if (!contents) {
+    return E_OUTOFMEMORY;
+  }
+
+  // NOTE: we intentionally use the Microsoft version of snprintf here because
+  // it does NOT null
+  // terminate strings which reach the maximum size of the buffer. Since we know
+  // that the formatted length here is totalLen, this call to _snprintf will
+  // format the string into the buffer without appending the null character.
+
+  if (!Preferences::GetBool(kShellIconPref, true)) {
+    _snprintf(contents, totalLen, shortcutFormatStr, asciiUrl.get());
+  } else {
+    _snprintf(contents, totalLen, shortcutFormatStr, asciiUrl.get(),
+              asciiPath.get());
+  }
+
+  ::GlobalUnlock(globalMem.get());
+
+  if (aFE.tymed & TYMED_ISTREAM) {
+    if (!mIsInOperation) {
+      // The drop target didn't initiate an async operation.
+      // We can't block CMemStream::Read.
+      event = nullptr;
+    }
+    RefPtr<IStream> stream =
+        new CMemStream(globalMem.disown(), totalLen, event.forget());
+    stream.forget(&aSTG.pstm);
+    aSTG.tymed = TYMED_ISTREAM;
+  } else {
+    if (event && event->IsInited()) {
+      event->Signal();  // We can't block reading the global memory
+    }
+    aSTG.hGlobal = globalMem.disown();
+    aSTG.tymed = TYMED_HGLOBAL;
+  }
+
+  return S_OK;
+}  // GetFileContentsInternetShortcut
+
+// check if specified flavour is present in the transferable
+bool nsDataObj ::IsFlavourPresent(const char* inFlavour) {
+  bool retval = false;
+  NS_ENSURE_TRUE(mTransferable, false);
+
+  // get the list of flavors available in the transferable
+  nsTArray<nsCString> flavors;
+  nsresult rv = mTransferable->FlavorsTransferableCanExport(flavors);
+  NS_ENSURE_SUCCESS(rv, false);
+
+  // try to find requested flavour
+  for (uint32_t i = 0; i < flavors.Length(); ++i) {
+    if (flavors[i].Equals(inFlavour)) {
+      retval = true;  // found it!
+      break;
+    }
+  }  // for each flavor
+
+  return retval;
+}
+
+HRESULT nsDataObj::GetPreferredDropEffect(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  HRESULT res = S_OK;
+  aSTG.tymed = TYMED_HGLOBAL;
+  aSTG.pUnkForRelease = nullptr;
+  HGLOBAL hGlobalMemory = nullptr;
+  hGlobalMemory = ::GlobalAlloc(GMEM_MOVEABLE, sizeof(DWORD));
+  if (hGlobalMemory) {
+    DWORD* pdw = (DWORD*)GlobalLock(hGlobalMemory);
+    // The PreferredDropEffect clipboard format is only registered if a
+    // drag/drop of an image happens from Mozilla to the desktop.  We want its
+    // value to be DROPEFFECT_MOVE in that case so that the file is moved from
+    // the temporary location, not copied. This value should, ideally, be set on
+    // the data object via SetData() but our IDataObject implementation doesn't
+    // implement SetData.  It adds data to the data object lazily only when the
+    // drop target asks for it.
+    *pdw = (DWORD)DROPEFFECT_MOVE;
+    GlobalUnlock(hGlobalMemory);
+  } else {
+    res = E_OUTOFMEMORY;
+  }
+  aSTG.hGlobal = hGlobalMemory;
+  return res;
+}
+
+//-----------------------------------------------------
+HRESULT nsDataObj::GetText(const nsACString& aDataFlavor, FORMATETC& aFE,
+                           STGMEDIUM& aSTG) {
+  void* data = nullptr;
+
+  const nsPromiseFlatCString& flavorStr = PromiseFlatCString(aDataFlavor);
+
+  // NOTE: CreateDataFromPrimitive creates new memory, that needs to be deleted
+  nsCOMPtr<nsISupports> genericDataWrapper;
+  nsresult rv = mTransferable->GetTransferData(
+      flavorStr.get(), getter_AddRefs(genericDataWrapper));
+  if (NS_FAILED(rv) || !genericDataWrapper) {
+    return E_FAIL;
+  }
+
+  uint32_t len;
+  nsPrimitiveHelpers::CreateDataFromPrimitive(
+      nsDependentCString(flavorStr.get()), genericDataWrapper, &data, &len);
+  if (!data) return E_FAIL;
+
+  HGLOBAL hGlobalMemory = nullptr;
+
+  aSTG.tymed = TYMED_HGLOBAL;
+  aSTG.pUnkForRelease = nullptr;
+
+  // We play games under the hood and advertise flavors that we know we
+  // can support, only they require a bit of conversion or munging of the data.
+  // Do that here.
+  //
+  // The transferable gives us data that is null-terminated, but this isn't
+  // reflected in the |len| parameter. Windoze apps expect this null to be there
+  // so bump our data buffer by the appropriate size to account for the null
+  // (one char for CF_TEXT, one char16_t for CF_UNICODETEXT).
+  DWORD allocLen = (DWORD)len;
+  if (aFE.cfFormat == CF_TEXT) {
+    // Someone is asking for text/plain; convert the unicode (assuming it's
+    // present) to text with the correct platform encoding.
+    size_t bufferSize = sizeof(char) * (len + 2);
+    char* plainTextData = static_cast<char*>(moz_xmalloc(bufferSize));
+    char16_t* castedUnicode = reinterpret_cast<char16_t*>(data);
+    int32_t plainTextLen =
+        WideCharToMultiByte(CP_ACP, 0, (LPCWSTR)castedUnicode, len / 2 + 1,
+                            plainTextData, bufferSize, NULL, NULL);
+    // replace the unicode data with our plaintext data. Recall that
+    // |plainTextLen| doesn't include the null in the length.
+    free(data);
+    if (plainTextLen) {
+      data = plainTextData;
+      allocLen = plainTextLen;
+    } else {
+      free(plainTextData);
+      NS_WARNING("Oh no, couldn't convert unicode to plain text");
+      return S_OK;
+    }
+  } else if (aFE.cfFormat == nsClipboard::GetHtmlClipboardFormat()) {
+    // Someone is asking for win32's HTML flavor. Convert our html fragment
+    // from unicode to UTF-8 then put it into a format specified by msft.
+    NS_ConvertUTF16toUTF8 converter(reinterpret_cast<char16_t*>(data));
+    char* utf8HTML = nullptr;
+    nsresult rv =
+        BuildPlatformHTML(converter.get(), &utf8HTML);  // null terminates
+
+    free(data);
+    if (NS_SUCCEEDED(rv) && utf8HTML) {
+      // replace the unicode data with our HTML data. Don't forget the null.
+      data = utf8HTML;
+      allocLen = strlen(utf8HTML) + sizeof(char);
+    } else {
+      NS_WARNING("Oh no, couldn't convert to HTML");
+      return S_OK;
+    }
+  } else if (aFE.cfFormat != nsClipboard::GetCustomClipboardFormat()) {
+    // we assume that any data that isn't caught above is unicode. This may
+    // be an erroneous assumption, but is true so far.
+    allocLen += sizeof(char16_t);
+  }
+
+  hGlobalMemory = (HGLOBAL)GlobalAlloc(GMEM_MOVEABLE, allocLen);
+
+  // Copy text to Global Memory Area
+  if (hGlobalMemory) {
+    char* dest = reinterpret_cast<char*>(GlobalLock(hGlobalMemory));
+    char* source = reinterpret_cast<char*>(data);
+    memcpy(dest, source, allocLen);  // copies the null as well
+    GlobalUnlock(hGlobalMemory);
+  }
+  aSTG.hGlobal = hGlobalMemory;
+
+  // Now, delete the memory that was created by CreateDataFromPrimitive (or our
+  // text/plain data)
+  free(data);
+
+  return S_OK;
+}
+
+//-----------------------------------------------------
+HRESULT nsDataObj::GetFile(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  uint32_t dfInx = 0;
+  ULONG count;
+  FORMATETC fe;
+  m_enumFE->Reset();
+  while (NOERROR == m_enumFE->Next(1, &fe, &count) &&
+         dfInx < mDataFlavors.Length()) {
+    if (mDataFlavors[dfInx].EqualsLiteral(kNativeImageMime))
+      return DropImage(aFE, aSTG);
+    if (mDataFlavors[dfInx].EqualsLiteral(kFileMime))
+      return DropFile(aFE, aSTG);
+    if (mDataFlavors[dfInx].EqualsLiteral(kFilePromiseMime))
+      return DropTempFile(aFE, aSTG);
+    dfInx++;
+  }
+  return E_FAIL;
+}
+
+HRESULT nsDataObj::DropFile(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  nsresult rv;
+  nsCOMPtr<nsISupports> genericDataWrapper;
+
+  if (NS_FAILED(mTransferable->GetTransferData(
+          kFileMime, getter_AddRefs(genericDataWrapper)))) {
+    return E_FAIL;
+  }
+  nsCOMPtr<nsIFile> file(do_QueryInterface(genericDataWrapper));
+  if (!file) return E_FAIL;
+
+  aSTG.tymed = TYMED_HGLOBAL;
+  aSTG.pUnkForRelease = nullptr;
+
+  nsAutoString path;
+  rv = file->GetPath(path);
+  if (NS_FAILED(rv)) return E_FAIL;
+
+  uint32_t allocLen = path.Length() + 2;
+  HGLOBAL hGlobalMemory = nullptr;
+  char16_t* dest;
+
+  hGlobalMemory = GlobalAlloc(GMEM_MOVEABLE,
+                              sizeof(DROPFILES) + allocLen * sizeof(char16_t));
+  if (!hGlobalMemory) return E_FAIL;
+
+  DROPFILES* pDropFile = (DROPFILES*)GlobalLock(hGlobalMemory);
+
+  // First, populate the drop file structure
+  pDropFile->pFiles = sizeof(DROPFILES);  // Offset to start of file name string
+  pDropFile->fNC = 0;
+  pDropFile->pt.x = 0;
+  pDropFile->pt.y = 0;
+  pDropFile->fWide = TRUE;
+
+  // Copy the filename right after the DROPFILES structure
+  dest = (char16_t*)(((char*)pDropFile) + pDropFile->pFiles);
+  memcpy(dest, path.get(), (allocLen - 1) * sizeof(char16_t));
+
+  // Two null characters are needed at the end of the file name.
+  // Lookup the CF_HDROP shell clipboard format for more info.
+  // Add the second null character right after the first one.
+  dest[allocLen - 1] = L'\0';
+
+  GlobalUnlock(hGlobalMemory);
+
+  aSTG.hGlobal = hGlobalMemory;
+
+  return S_OK;
+}
+
+HRESULT nsDataObj::DropImage(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  nsresult rv;
+  if (!mCachedTempFile) {
+    nsCOMPtr<nsISupports> genericDataWrapper;
+
+    if (NS_FAILED(mTransferable->GetTransferData(
+            kNativeImageMime, getter_AddRefs(genericDataWrapper)))) {
+      return E_FAIL;
+    }
+    nsCOMPtr<imgIContainer> image(do_QueryInterface(genericDataWrapper));
+    if (!image) return E_FAIL;
+
+    nsCOMPtr<imgITools> imgTools =
+        do_CreateInstance("@mozilla.org/image/tools;1");
+    nsCOMPtr<nsIInputStream> inputStream;
+    rv = imgTools->EncodeImage(image, nsLiteralCString(IMAGE_BMP),
+                               u"bpp=32;version=3"_ns,
+                               getter_AddRefs(inputStream));
+    if (NS_FAILED(rv) || !inputStream) {
+      return E_FAIL;
+    }
+
+    nsCOMPtr<imgIEncoder> encoder = do_QueryInterface(inputStream);
+    if (!encoder) {
+      return E_FAIL;
+    }
+
+    uint32_t size = 0;
+    rv = encoder->GetImageBufferUsed(&size);
+    if (NS_FAILED(rv)) {
+      return E_FAIL;
+    }
+
+    char* src = nullptr;
+    rv = encoder->GetImageBuffer(&src);
+    if (NS_FAILED(rv) || !src) {
+      return E_FAIL;
+    }
+
+    // Save the bitmap to a temporary location.
+    nsCOMPtr<nsIFile> dropFile;
+    rv = NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(dropFile));
+    if (!dropFile) {
+      return E_FAIL;
+    }
+
+    // Filename must be random so as not to confuse apps like
+    // Photoshop which handle multiple drags into a single window.
+    char buf[13];
+    nsCString filename;
+    NS_MakeRandomString(buf, 8);
+    memcpy(buf + 8, ".bmp", 5);
+    filename.Append(nsDependentCString(buf, 12));
+    dropFile->AppendNative(filename);
+    rv = dropFile->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0660);
+    if (NS_FAILED(rv)) {
+      return E_FAIL;
+    }
+
+    // Cache the temp file so we can delete it later and so
+    // it doesn't get recreated over and over on multiple calls
+    // which does occur from windows shell.
+    dropFile->Clone(getter_AddRefs(mCachedTempFile));
+
+    // Write the data to disk.
+    nsCOMPtr<nsIOutputStream> outStream;
+    rv = NS_NewLocalFileOutputStream(getter_AddRefs(outStream), dropFile);
+    if (NS_FAILED(rv)) {
+      return E_FAIL;
+    }
+
+    uint32_t written = 0;
+    rv = outStream->Write(src, size, &written);
+    if (NS_FAILED(rv) || written != size) {
+      return E_FAIL;
+    }
+
+    outStream->Close();
+  }
+
+  // Pass the file name back to the drop target so that it can access the file.
+  nsAutoString path;
+  rv = mCachedTempFile->GetPath(path);
+  if (NS_FAILED(rv)) return E_FAIL;
+
+  // Two null characters are needed to terminate the file name list.
+  HGLOBAL hGlobalMemory = nullptr;
+
+  uint32_t allocLen = path.Length() + 2;
+
+  aSTG.tymed = TYMED_HGLOBAL;
+  aSTG.pUnkForRelease = nullptr;
+
+  hGlobalMemory = GlobalAlloc(GMEM_MOVEABLE,
+                              sizeof(DROPFILES) + allocLen * sizeof(char16_t));
+  if (!hGlobalMemory) return E_FAIL;
+
+  DROPFILES* pDropFile = (DROPFILES*)GlobalLock(hGlobalMemory);
+
+  // First, populate the drop file structure.
+  pDropFile->pFiles =
+      sizeof(DROPFILES);  // Offset to start of file name char array.
+  pDropFile->fNC = 0;
+  pDropFile->pt.x = 0;
+  pDropFile->pt.y = 0;
+  pDropFile->fWide = TRUE;
+
+  // Copy the filename right after the DROPFILES structure.
+  char16_t* dest = (char16_t*)(((char*)pDropFile) + pDropFile->pFiles);
+  memcpy(dest, path.get(),
+         (allocLen - 1) *
+             sizeof(char16_t));  // Copies the null character in path as well.
+
+  // Two null characters are needed at the end of the file name.
+  // Lookup the CF_HDROP shell clipboard format for more info.
+  // Add the second null character right after the first one.
+  dest[allocLen - 1] = L'\0';
+
+  GlobalUnlock(hGlobalMemory);
+
+  aSTG.hGlobal = hGlobalMemory;
+
+  return S_OK;
+}
+
+HRESULT nsDataObj::DropTempFile(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  nsresult rv;
+  if (!mCachedTempFile) {
+    // Tempfile will need a temporary location.
+    nsCOMPtr<nsIFile> dropFile;
+    rv = NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(dropFile));
+    if (!dropFile) return E_FAIL;
+
+    // Filename must be random
+    nsCString filename;
+    nsAutoString wideFileName;
+    nsCOMPtr<nsIURI> sourceURI;
+    HRESULT res;
+    res = GetDownloadDetails(getter_AddRefs(sourceURI), wideFileName);
+    if (FAILED(res)) return res;
+    NS_CopyUnicodeToNative(wideFileName, filename);
+
+    dropFile->AppendNative(filename);
+    rv = dropFile->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0660);
+    if (NS_FAILED(rv)) return E_FAIL;
+
+    // Cache the temp file so we can delete it later and so
+    // it doesn't get recreated over and over on multiple calls
+    // which does occur from windows shell.
+    dropFile->Clone(getter_AddRefs(mCachedTempFile));
+
+    // Write the data to disk.
+    nsCOMPtr<nsIOutputStream> outStream;
+    rv = NS_NewLocalFileOutputStream(getter_AddRefs(outStream), dropFile);
+    if (NS_FAILED(rv)) return E_FAIL;
+
+    IStream* pStream = nullptr;
+    nsDataObj::CreateStream(&pStream);
+    NS_ENSURE_TRUE(pStream, E_FAIL);
+
+    char buffer[512];
+    ULONG readCount = 0;
+    uint32_t writeCount = 0;
+    while (1) {
+      HRESULT hres = pStream->Read(buffer, sizeof(buffer), &readCount);
+      if (FAILED(hres)) return E_FAIL;
+      if (readCount == 0) break;
+      rv = outStream->Write(buffer, readCount, &writeCount);
+      if (NS_FAILED(rv)) return E_FAIL;
+    }
+    outStream->Close();
+    pStream->Release();
+  }
+
+  // Pass the file name back to the drop target so that it can access the file.
+  nsAutoString path;
+  rv = mCachedTempFile->GetPath(path);
+  if (NS_FAILED(rv)) return E_FAIL;
+
+  uint32_t allocLen = path.Length() + 2;
+
+  // Two null characters are needed to terminate the file name list.
+  HGLOBAL hGlobalMemory = nullptr;
+
+  aSTG.tymed = TYMED_HGLOBAL;
+  aSTG.pUnkForRelease = nullptr;
+
+  hGlobalMemory = GlobalAlloc(GMEM_MOVEABLE,
+                              sizeof(DROPFILES) + allocLen * sizeof(char16_t));
+  if (!hGlobalMemory) return E_FAIL;
+
+  DROPFILES* pDropFile = (DROPFILES*)GlobalLock(hGlobalMemory);
+
+  // First, populate the drop file structure.
+  pDropFile->pFiles =
+      sizeof(DROPFILES);  // Offset to start of file name char array.
+  pDropFile->fNC = 0;
+  pDropFile->pt.x = 0;
+  pDropFile->pt.y = 0;
+  pDropFile->fWide = TRUE;
+
+  // Copy the filename right after the DROPFILES structure.
+  char16_t* dest = (char16_t*)(((char*)pDropFile) + pDropFile->pFiles);
+  memcpy(dest, path.get(),
+         (allocLen - 1) *
+             sizeof(char16_t));  // Copies the null character in path as well.
+
+  // Two null characters are needed at the end of the file name.
+  // Lookup the CF_HDROP shell clipboard format for more info.
+  // Add the second null character right after the first one.
+  dest[allocLen - 1] = L'\0';
+
+  GlobalUnlock(hGlobalMemory);
+
+  aSTG.hGlobal = hGlobalMemory;
+
+  return S_OK;
+}
+
+//-----------------------------------------------------
+// Registers the DataFlavor/FE pair.
+//-----------------------------------------------------
+void nsDataObj::AddDataFlavor(const char* aDataFlavor, LPFORMATETC aFE) {
+  // These two lists are the mapping to and from data flavors and FEs.
+  // Later, OLE will tell us it needs a certain type of FORMATETC (text,
+  // unicode, etc) unicode, etc), so we will look up the data flavor that
+  // corresponds to the FE and then ask the transferable for that type of data.
+  mDataFlavors.AppendElement(aDataFlavor);
+  m_enumFE->AddFormatEtc(aFE);
+}
+
+//-----------------------------------------------------
+// Sets the transferable object
+//-----------------------------------------------------
+void nsDataObj::SetTransferable(nsITransferable* aTransferable) {
+  NS_IF_RELEASE(mTransferable);
+
+  mTransferable = aTransferable;
+  if (nullptr == mTransferable) {
+    return;
+  }
+
+  NS_ADDREF(mTransferable);
+
+  return;
+}
+
+//
+// ExtractURL
+//
+// Roots around in the transferable for the appropriate flavor that indicates
+// a url and pulls out the url portion of the data. Used mostly for creating
+// internet shortcuts on the desktop. The url flavor is of the format:
+//
+//   <url> <linefeed> <page title>
+//
+nsresult nsDataObj ::ExtractShortcutURL(nsString& outURL) {
+  NS_ASSERTION(mTransferable, "We don't have a good transferable");
+  nsresult rv = NS_ERROR_FAILURE;
+
+  nsCOMPtr<nsISupports> genericURL;
+  if (NS_SUCCEEDED(mTransferable->GetTransferData(
+          kURLMime, getter_AddRefs(genericURL)))) {
+    nsCOMPtr<nsISupportsString> urlObject(do_QueryInterface(genericURL));
+    if (urlObject) {
+      nsAutoString url;
+      urlObject->GetData(url);
+      outURL = url;
+
+      // find the first linefeed in the data, that's where the url ends. trunc
+      // the result string at that point.
+      int32_t lineIndex = outURL.FindChar('\n');
+      NS_ASSERTION(lineIndex > 0,
+                   "Format for url flavor is <url> <linefeed> <page title>");
+      if (lineIndex > 0) {
+        outURL.Truncate(lineIndex);
+        rv = NS_OK;
+      }
+    }
+  } else if (NS_SUCCEEDED(mTransferable->GetTransferData(
+                 kURLDataMime, getter_AddRefs(genericURL))) ||
+             NS_SUCCEEDED(mTransferable->GetTransferData(
+                 kURLPrivateMime, getter_AddRefs(genericURL)))) {
+    nsCOMPtr<nsISupportsString> urlObject(do_QueryInterface(genericURL));
+    if (urlObject) {
+      nsAutoString url;
+      urlObject->GetData(url);
+      outURL = url;
+
+      rv = NS_OK;
+    }
+
+  }  // if found flavor
+
+  return rv;
+
+}  // ExtractShortcutURL
+
+//
+// ExtractShortcutTitle
+//
+// Roots around in the transferable for the appropriate flavor that indicates
+// a url and pulls out the title portion of the data. Used mostly for creating
+// internet shortcuts on the desktop. The url flavor is of the format:
+//
+//   <url> <linefeed> <page title>
+//
+nsresult nsDataObj ::ExtractShortcutTitle(nsString& outTitle) {
+  NS_ASSERTION(mTransferable, "We'd don't have a good transferable");
+  nsresult rv = NS_ERROR_FAILURE;
+
+  nsCOMPtr<nsISupports> genericURL;
+  if (NS_SUCCEEDED(mTransferable->GetTransferData(
+          kURLMime, getter_AddRefs(genericURL)))) {
+    nsCOMPtr<nsISupportsString> urlObject(do_QueryInterface(genericURL));
+    if (urlObject) {
+      nsAutoString url;
+      urlObject->GetData(url);
+
+      // find the first linefeed in the data, that's where the url ends. we want
+      // everything after that linefeed. FindChar() returns -1 if we can't find
+      int32_t lineIndex = url.FindChar('\n');
+      NS_ASSERTION(lineIndex != -1,
+                   "Format for url flavor is <url> <linefeed> <page title>");
+      if (lineIndex != -1) {
+        url.Mid(outTitle, lineIndex + 1, url.Length() - (lineIndex + 1));
+        rv = NS_OK;
+      }
+    }
+  }  // if found flavor
+
+  return rv;
+
+}  // ExtractShortcutTitle
+
+//
+// BuildPlatformHTML
+//
+// Munge our HTML data to win32's CF_HTML spec. Basically, put the requisite
+// header information on it. This will null-terminate |outPlatformHTML|. See
+//  https://docs.microsoft.com/en-us/windows/win32/dataxchg/html-clipboard-format
+// for details.
+//
+// We assume that |inOurHTML| is already a fragment (ie, doesn't have <HTML>
+// or <BODY> tags). We'll wrap the fragment with them to make other apps
+// happy.
+//
+nsresult nsDataObj ::BuildPlatformHTML(const char* inOurHTML,
+                                       char** outPlatformHTML) {
+  *outPlatformHTML = nullptr;
+  nsDependentCString inHTMLString(inOurHTML);
+
+  // Do we already have mSourceURL from a drag?
+  if (mSourceURL.IsEmpty()) {
+    nsAutoString url;
+    ExtractShortcutURL(url);
+
+    AppendUTF16toUTF8(url, mSourceURL);
+  }
+
+  constexpr auto kStartHTMLPrefix = "Version:0.9\r\nStartHTML:"_ns;
+  constexpr auto kEndHTMLPrefix = "\r\nEndHTML:"_ns;
+  constexpr auto kStartFragPrefix = "\r\nStartFragment:"_ns;
+  constexpr auto kEndFragPrefix = "\r\nEndFragment:"_ns;
+  constexpr auto kStartSourceURLPrefix = "\r\nSourceURL:"_ns;
+  constexpr auto kEndFragTrailer = "\r\n"_ns;
+
+  // The CF_HTML's size is embedded in the fragment, in such a way that the
+  // number of digits in the size is part of the size itself. While it _is_
+  // technically possible to compute the necessary size of the size-field
+  // precisely -- by trial and error, if nothing else -- it's simpler just to
+  // pick a rough but generous estimate and zero-pad it. (Zero-padding is
+  // explicitly permitted by the format definition.)
+  //
+  // Originally, in 2001, the "rough but generous estimate" was 8 digits. While
+  // a maximum size of (10**9 - 1) bytes probably would have covered all
+  // possible use-cases at the time, it's somewhat more likely to overflow
+  // nowadays. Nonetheless, for the sake of backwards compatibility with any
+  // misbehaving consumers of our existing CF_HTML output, we retain exactly
+  // that padding for (most) fragments where it suffices. (No such misbehaving
+  // consumers are actually known, so this is arguably paranoia.)
+  //
+  // It is now 2022. A padding size of 16 will cover up to about 8.8 petabytes,
+  // which should be enough for at least the next few years or so.
+  const size_t numberLength = inHTMLString.Length() < 9999'0000 ? 8 : 16;
+
+  const size_t sourceURLLength = mSourceURL.Length();
+
+  const size_t fixedHeaderLen =
+      kStartHTMLPrefix.Length() + kEndHTMLPrefix.Length() +
+      kStartFragPrefix.Length() + kEndFragPrefix.Length() +
+      kEndFragTrailer.Length() + (4 * numberLength);
+
+  const size_t totalHeaderLen =
+      fixedHeaderLen + (sourceURLLength > 0
+                            ? kStartSourceURLPrefix.Length() + sourceURLLength
+                            : 0);
+
+  constexpr auto kHeaderString = "<html><body>\r\n<!--StartFragment-->"_ns;
+  constexpr auto kTrailingString =
+      "<!--EndFragment-->\r\n"
+      "</body>\r\n"
+      "</html>"_ns;
+
+  // calculate the offsets
+  size_t startHTMLOffset = totalHeaderLen;
+  size_t startFragOffset = startHTMLOffset + kHeaderString.Length();
+
+  size_t endFragOffset = startFragOffset + inHTMLString.Length();
+  size_t endHTMLOffset = endFragOffset + kTrailingString.Length();
+
+  // now build the final version
+  nsCString clipboardString;
+  clipboardString.SetCapacity(endHTMLOffset);
+
+  const int numberLengthInt = static_cast<int>(numberLength);
+  clipboardString.Append(kStartHTMLPrefix);
+  clipboardString.AppendPrintf("%0*zu", numberLengthInt, startHTMLOffset);
+
+  clipboardString.Append(kEndHTMLPrefix);
+  clipboardString.AppendPrintf("%0*zu", numberLengthInt, endHTMLOffset);
+
+  clipboardString.Append(kStartFragPrefix);
+  clipboardString.AppendPrintf("%0*zu", numberLengthInt, startFragOffset);
+
+  clipboardString.Append(kEndFragPrefix);
+  clipboardString.AppendPrintf("%0*zu", numberLengthInt, endFragOffset);
+
+  if (sourceURLLength > 0) {
+    clipboardString.Append(kStartSourceURLPrefix);
+    clipboardString.Append(mSourceURL);
+  }
+
+  clipboardString.Append(kEndFragTrailer);
+
+  // Assert that the positional values were correct as we pass by their
+  // corresponding positions.
+  MOZ_ASSERT(clipboardString.Length() == startHTMLOffset);
+  clipboardString.Append(kHeaderString);
+  MOZ_ASSERT(clipboardString.Length() == startFragOffset);
+  clipboardString.Append(inHTMLString);
+  MOZ_ASSERT(clipboardString.Length() == endFragOffset);
+  clipboardString.Append(kTrailingString);
+  MOZ_ASSERT(clipboardString.Length() == endHTMLOffset);
+
+  *outPlatformHTML = ToNewCString(clipboardString, mozilla::fallible);
+  if (!*outPlatformHTML) return NS_ERROR_OUT_OF_MEMORY;
+
+  return NS_OK;
+}
+
+HRESULT
+nsDataObj ::GetUniformResourceLocator(FORMATETC& aFE, STGMEDIUM& aSTG,
+                                      bool aIsUnicode) {
+  HRESULT res = S_OK;
+  if (IsFlavourPresent(kURLMime)) {
+    if (aIsUnicode)
+      res = ExtractUniformResourceLocatorW(aFE, aSTG);
+    else
+      res = ExtractUniformResourceLocatorA(aFE, aSTG);
+  } else
+    NS_WARNING("Not yet implemented\n");
+  return res;
+}
+
+HRESULT
+nsDataObj::ExtractUniformResourceLocatorA(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  HRESULT result = S_OK;
+
+  nsAutoString url;
+  if (NS_FAILED(ExtractShortcutURL(url))) return E_OUTOFMEMORY;
+
+  NS_LossyConvertUTF16toASCII asciiUrl(url);
+  const int totalLen = asciiUrl.Length() + 1;
+  HGLOBAL hGlobalMemory = GlobalAlloc(GMEM_ZEROINIT | GMEM_SHARE, totalLen);
+  if (!hGlobalMemory) return E_OUTOFMEMORY;
+
+  char* contents = reinterpret_cast<char*>(GlobalLock(hGlobalMemory));
+  if (!contents) {
+    GlobalFree(hGlobalMemory);
+    return E_OUTOFMEMORY;
+  }
+
+  strcpy(contents, asciiUrl.get());
+  GlobalUnlock(hGlobalMemory);
+  aSTG.hGlobal = hGlobalMemory;
+  aSTG.tymed = TYMED_HGLOBAL;
+
+  return result;
+}
+
+HRESULT
+nsDataObj::ExtractUniformResourceLocatorW(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  HRESULT result = S_OK;
+
+  nsAutoString url;
+  if (NS_FAILED(ExtractShortcutURL(url))) return E_OUTOFMEMORY;
+
+  const int totalLen = (url.Length() + 1) * sizeof(char16_t);
+  HGLOBAL hGlobalMemory = GlobalAlloc(GMEM_ZEROINIT | GMEM_SHARE, totalLen);
+  if (!hGlobalMemory) return E_OUTOFMEMORY;
+
+  wchar_t* contents = reinterpret_cast<wchar_t*>(GlobalLock(hGlobalMemory));
+  if (!contents) {
+    GlobalFree(hGlobalMemory);
+    return E_OUTOFMEMORY;
+  }
+
+  wcscpy(contents, url.get());
+  GlobalUnlock(hGlobalMemory);
+  aSTG.hGlobal = hGlobalMemory;
+  aSTG.tymed = TYMED_HGLOBAL;
+
+  return result;
+}
+
+// Gets the filename from the kFilePromiseURLMime flavour
+HRESULT nsDataObj::GetDownloadDetails(nsIURI** aSourceURI,
+                                      nsAString& aFilename) {
+  *aSourceURI = nullptr;
+
+  NS_ENSURE_TRUE(mTransferable, E_FAIL);
+
+  // get the URI from the kFilePromiseURLMime flavor
+  nsCOMPtr<nsISupports> urlPrimitive;
+  nsresult rv = mTransferable->GetTransferData(kFilePromiseURLMime,
+                                               getter_AddRefs(urlPrimitive));
+  NS_ENSURE_SUCCESS(rv, E_FAIL);
+  nsCOMPtr<nsISupportsString> srcUrlPrimitive = do_QueryInterface(urlPrimitive);
+  NS_ENSURE_TRUE(srcUrlPrimitive, E_FAIL);
+
+  nsAutoString srcUri;
+  srcUrlPrimitive->GetData(srcUri);
+  if (srcUri.IsEmpty()) return E_FAIL;
+  nsCOMPtr<nsIURI> sourceURI;
+  NS_NewURI(getter_AddRefs(sourceURI), srcUri);
+
+  nsAutoString srcFileName;
+  nsCOMPtr<nsISupports> fileNamePrimitive;
+  Unused << mTransferable->GetTransferData(kFilePromiseDestFilename,
+                                           getter_AddRefs(fileNamePrimitive));
+  nsCOMPtr<nsISupportsString> srcFileNamePrimitive =
+      do_QueryInterface(fileNamePrimitive);
+  if (srcFileNamePrimitive) {
+    srcFileNamePrimitive->GetData(srcFileName);
+  } else {
+    nsCOMPtr<nsIURL> sourceURL = do_QueryInterface(sourceURI);
+    if (!sourceURL) return E_FAIL;
+
+    nsAutoCString urlFileName;
+    sourceURL->GetFileName(urlFileName);
+    NS_UnescapeURL(urlFileName);
+    CopyUTF8toUTF16(urlFileName, srcFileName);
+  }
+
+  // make the name safe for the filesystem
+  ValidateFilename(srcFileName, false);
+  if (srcFileName.IsEmpty()) return E_FAIL;
+
+  sourceURI.swap(*aSourceURI);
+  aFilename = srcFileName;
+  return S_OK;
+}
+
+HRESULT nsDataObj::GetFileDescriptor_IStreamA(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  HGLOBAL fileGroupDescHandle =
+      ::GlobalAlloc(GMEM_ZEROINIT | GMEM_SHARE, sizeof(FILEGROUPDESCRIPTORW));
+  NS_ENSURE_TRUE(fileGroupDescHandle, E_OUTOFMEMORY);
+
+  LPFILEGROUPDESCRIPTORA fileGroupDescA =
+      reinterpret_cast<LPFILEGROUPDESCRIPTORA>(GlobalLock(fileGroupDescHandle));
+  if (!fileGroupDescA) {
+    ::GlobalFree(fileGroupDescHandle);
+    return E_OUTOFMEMORY;
+  }
+
+  nsAutoString wideFileName;
+  HRESULT res;
+  nsCOMPtr<nsIURI> sourceURI;
+  res = GetDownloadDetails(getter_AddRefs(sourceURI), wideFileName);
+  if (FAILED(res)) {
+    ::GlobalFree(fileGroupDescHandle);
+    return res;
+  }
+
+  nsAutoCString nativeFileName;
+  NS_CopyUnicodeToNative(wideFileName, nativeFileName);
+
+  strncpy(fileGroupDescA->fgd[0].cFileName, nativeFileName.get(), MAX_PATH - 1);
+  fileGroupDescA->fgd[0].cFileName[MAX_PATH - 1] = '\0';
+
+  // one file in the file block
+  fileGroupDescA->cItems = 1;
+  fileGroupDescA->fgd[0].dwFlags = FD_PROGRESSUI;
+
+  GlobalUnlock(fileGroupDescHandle);
+  aSTG.hGlobal = fileGroupDescHandle;
+  aSTG.tymed = TYMED_HGLOBAL;
+
+  return S_OK;
+}
+
+HRESULT nsDataObj::GetFileDescriptor_IStreamW(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  HGLOBAL fileGroupDescHandle =
+      ::GlobalAlloc(GMEM_ZEROINIT | GMEM_SHARE, sizeof(FILEGROUPDESCRIPTORW));
+  NS_ENSURE_TRUE(fileGroupDescHandle, E_OUTOFMEMORY);
+
+  LPFILEGROUPDESCRIPTORW fileGroupDescW =
+      reinterpret_cast<LPFILEGROUPDESCRIPTORW>(GlobalLock(fileGroupDescHandle));
+  if (!fileGroupDescW) {
+    ::GlobalFree(fileGroupDescHandle);
+    return E_OUTOFMEMORY;
+  }
+
+  nsAutoString wideFileName;
+  HRESULT res;
+  nsCOMPtr<nsIURI> sourceURI;
+  res = GetDownloadDetails(getter_AddRefs(sourceURI), wideFileName);
+  if (FAILED(res)) {
+    ::GlobalFree(fileGroupDescHandle);
+    return res;
+  }
+
+  wcsncpy(fileGroupDescW->fgd[0].cFileName, wideFileName.get(), MAX_PATH - 1);
+  fileGroupDescW->fgd[0].cFileName[MAX_PATH - 1] = '\0';
+  // one file in the file block
+  fileGroupDescW->cItems = 1;
+  fileGroupDescW->fgd[0].dwFlags = FD_PROGRESSUI;
+
+  GlobalUnlock(fileGroupDescHandle);
+  aSTG.hGlobal = fileGroupDescHandle;
+  aSTG.tymed = TYMED_HGLOBAL;
+
+  return S_OK;
+}
+
+HRESULT nsDataObj::GetFileContents_IStream(FORMATETC& aFE, STGMEDIUM& aSTG) {
+  IStream* pStream = nullptr;
+
+  nsDataObj::CreateStream(&pStream);
+  NS_ENSURE_TRUE(pStream, E_FAIL);
+
+  aSTG.tymed = TYMED_ISTREAM;
+  aSTG.pstm = pStream;
+  aSTG.pUnkForRelease = nullptr;
+
+  return S_OK;
+}
diff --git a/widget/windows/nsDataObj.h b/widget/windows/nsDataObj.h
new file mode 100644
index 0000000000..17683e371a
--- /dev/null
+++ b/widget/windows/nsDataObj.h
@@ -0,0 +1,315 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _NSDATAOBJ_H_
+#define _NSDATAOBJ_H_
+
+#include <oleidl.h>
+#include <shldisp.h>
+
+#include "mozilla/glue/WinUtils.h"
+#include "mozilla/LazyIdleThread.h"
+#include "nsCOMPtr.h"
+#include "nsString.h"
+#include "nsIFile.h"
+#include "nsIURI.h"
+#include "nsIStreamListener.h"
+#include "nsIChannel.h"
+#include "nsCOMArray.h"
+#include "nsITimer.h"
+#include "nsIURI.h"
+#include "nsString.h"
+#include "nsWindowsHelpers.h"
+
+class nsICookieJarSettings;
+class nsIPrincipal;
+class nsIReferrerInfo;
+class nsIThread;
+class nsITransferable;
+class CEnumFormatEtc;
+
+/*
+ * This ole registered class is used to facilitate drag-drop of objects which
+ * can be adapted by an object derived from CfDragDrop. The CfDragDrop is
+ * associated with instances via SetDragDrop().
+ */
+class nsDataObj : public IDataObject, public IDataObjectAsyncCapability {
+  RefPtr<mozilla::LazyIdleThread> mIOThread;
+
+ public:  // construction, destruction
+  explicit nsDataObj(nsIURI* uri = nullptr);
+
+ protected:
+  virtual ~nsDataObj();
+
+ public:  // IUnknown methods - see iunknown.h for documentation
+  STDMETHODIMP_(ULONG) AddRef() override;
+  STDMETHODIMP QueryInterface(REFIID, void**) override;
+  STDMETHODIMP_(ULONG) Release() override;
+
+  // support for clipboard
+  virtual void AddDataFlavor(const char* aDataFlavor, LPFORMATETC aFE);
+  void SetTransferable(nsITransferable* aTransferable);
+
+ public:  // IDataObject methods - these are general comments. see CfDragDrop
+          // for overriding behavior
+  // Store data in pSTM according to the format specified by pFE, if the
+  // format is supported (supported formats are specified in CfDragDrop::
+  // GetFormats) and return NOERROR; otherwise return DATA_E_FORMATETC. It
+  // is the callers responsibility to free pSTM if NOERROR is returned.
+  STDMETHODIMP GetData(LPFORMATETC pFE, LPSTGMEDIUM pSTM) override;
+
+  // Similar to GetData except that the caller allocates the structure
+  // referenced by pSTM.
+  STDMETHODIMP GetDataHere(LPFORMATETC pFE, LPSTGMEDIUM pSTM) override;
+
+  // Returns S_TRUE if this object supports the format specified by pSTM,
+  // S_FALSE otherwise.
+  STDMETHODIMP QueryGetData(LPFORMATETC pFE) override;
+
+  // Set pCanonFE to the canonical format of pFE if one exists and return
+  // NOERROR, otherwise return DATA_S_SAMEFORMATETC. A canonical format
+  // implies an identical rendering.
+  STDMETHODIMP GetCanonicalFormatEtc(LPFORMATETC pFE,
+                                     LPFORMATETC pCanonFE) final;
+
+  // Set this objects data according to the format specified by pFE and
+  // the storage medium specified by pSTM and return NOERROR, if the format
+  // is supported. If release is TRUE this object must release the storage
+  // associated with pSTM.
+  STDMETHODIMP SetData(LPFORMATETC pFE, LPSTGMEDIUM pSTM,
+                       BOOL release) override;
+
+  // Set ppEnum to an IEnumFORMATETC object which will iterate all of the
+  // data formats that this object supports. direction is either DATADIR_GET
+  // or DATADIR_SET.
+  STDMETHODIMP EnumFormatEtc(DWORD direction, LPENUMFORMATETC* ppEnum) final;
+
+  // Set up an advisory connection to this object based on the format specified
+  // by pFE, flags, and the pAdvise. Set pConn to the established advise
+  // connection.
+  STDMETHODIMP DAdvise(LPFORMATETC pFE, DWORD flags, LPADVISESINK pAdvise,
+                       DWORD* pConn) final;
+
+  // Turn off advising of a previous call to DAdvise which set pConn.
+  STDMETHODIMP DUnadvise(DWORD pConn) final;
+
+  // Set ppEnum to an IEnumSTATDATA object which will iterate over the
+  // existing objects which have established advisory connections to this
+  // object.
+  STDMETHODIMP EnumDAdvise(LPENUMSTATDATA* ppEnum) final;
+
+  // IDataObjectAsyncCapability methods
+  STDMETHODIMP EndOperation(HRESULT hResult, IBindCtx* pbcReserved,
+                            DWORD dwEffects) final;
+  STDMETHODIMP GetAsyncMode(BOOL* pfIsOpAsync) final;
+  STDMETHODIMP InOperation(BOOL* pfInAsyncOp) final;
+  STDMETHODIMP SetAsyncMode(BOOL fDoOpAsync) final;
+  STDMETHODIMP StartOperation(IBindCtx* pbcReserved) final;
+
+ private:  // other methods
+  // Gets the filename from the kFilePromiseURLMime flavour
+  HRESULT GetDownloadDetails(nsIURI** aSourceURI, nsAString& aFilename);
+
+  // help determine the kind of drag
+  bool IsFlavourPresent(const char* inFlavour);
+
+ protected:
+  HRESULT GetFile(FORMATETC& aFE, STGMEDIUM& aSTG);
+  HRESULT GetText(const nsACString& aDF, FORMATETC& aFE, STGMEDIUM& aSTG);
+
+ private:
+  HRESULT GetDib(const nsACString& inFlavor, FORMATETC&, STGMEDIUM& aSTG);
+
+  HRESULT DropImage(FORMATETC& aFE, STGMEDIUM& aSTG);
+  HRESULT DropFile(FORMATETC& aFE, STGMEDIUM& aSTG);
+  HRESULT DropTempFile(FORMATETC& aFE, STGMEDIUM& aSTG);
+
+  HRESULT GetUniformResourceLocator(FORMATETC& aFE, STGMEDIUM& aSTG,
+                                    bool aIsUnicode);
+  HRESULT ExtractUniformResourceLocatorA(FORMATETC& aFE, STGMEDIUM& aSTG);
+  HRESULT ExtractUniformResourceLocatorW(FORMATETC& aFE, STGMEDIUM& aSTG);
+  HRESULT GetFileDescriptor(FORMATETC& aFE, STGMEDIUM& aSTG, bool aIsUnicode);
+
+ protected:
+  HRESULT GetFileContents(FORMATETC& aFE, STGMEDIUM& aSTG);
+
+ private:
+  HRESULT GetPreferredDropEffect(FORMATETC& aFE, STGMEDIUM& aSTG);
+
+  // Provide the structures needed for an internet shortcut by the shell
+  HRESULT GetFileDescriptorInternetShortcutA(FORMATETC& aFE, STGMEDIUM& aSTG);
+  HRESULT GetFileDescriptorInternetShortcutW(FORMATETC& aFE, STGMEDIUM& aSTG);
+  HRESULT GetFileContentsInternetShortcut(FORMATETC& aFE, STGMEDIUM& aSTG);
+
+  // IStream implementation
+  HRESULT GetFileDescriptor_IStreamA(FORMATETC& aFE, STGMEDIUM& aSTG);
+  HRESULT GetFileDescriptor_IStreamW(FORMATETC& aFE, STGMEDIUM& aSTG);
+  HRESULT GetFileContents_IStream(FORMATETC& aFE, STGMEDIUM& aSTG);
+
+  nsresult ExtractShortcutURL(nsString& outURL);
+  nsresult ExtractShortcutTitle(nsString& outTitle);
+
+  // munge our HTML data to win32's CF_HTML spec. Will null terminate
+  nsresult BuildPlatformHTML(const char* inOurHTML, char** outPlatformHTML);
+
+  // Used for the SourceURL part of CF_HTML
+  nsCString mSourceURL;
+
+ protected:
+  BOOL FormatsMatch(const FORMATETC& source, const FORMATETC& target) const;
+
+  ULONG m_cRef;  // the reference count
+
+ private:
+  nsTArray<nsCString> mDataFlavors;
+
+  nsITransferable* mTransferable;  // nsDataObj owns and ref counts
+                                   // nsITransferable, the nsITransferable does
+                                   // know anything about the nsDataObj
+
+ protected:
+  CEnumFormatEtc* m_enumFE;  // Ownership Rules:
+                             // nsDataObj owns and ref counts CEnumFormatEtc,
+
+ private:
+  nsCOMPtr<nsIFile> mCachedTempFile;
+  RefPtr<nsDataObj> mKeepAlive;
+
+  BOOL mIsAsyncMode;
+  BOOL mIsInOperation;
+  ///////////////////////////////////////////////////////////////////////////////
+  // CStream class implementation
+  // this class is used in Drag and drop with download sample
+  // called from IDataObject::GetData
+  class CStreamBase : public IStream {
+    // IStream
+    STDMETHODIMP Clone(IStream** ppStream) final;
+    STDMETHODIMP Commit(DWORD dwFrags) final;
+    STDMETHODIMP CopyTo(IStream* pDestStream, ULARGE_INTEGER nBytesToCopy,
+                        ULARGE_INTEGER* nBytesRead,
+                        ULARGE_INTEGER* nBytesWritten) final;
+    STDMETHODIMP LockRegion(ULARGE_INTEGER nStart, ULARGE_INTEGER nBytes,
+                            DWORD dwFlags) final;
+    STDMETHODIMP Revert(void) final;
+    STDMETHODIMP Seek(LARGE_INTEGER nMove, DWORD dwOrigin,
+                      ULARGE_INTEGER* nNewPos) final;
+    STDMETHODIMP SetSize(ULARGE_INTEGER nNewSize) final;
+    STDMETHODIMP UnlockRegion(ULARGE_INTEGER nStart, ULARGE_INTEGER nBytes,
+                              DWORD dwFlags) final;
+    STDMETHODIMP Write(const void* pvBuffer, ULONG nBytesToRead,
+                       ULONG* nBytesRead) final;
+
+   protected:
+    uint32_t mStreamRead;
+
+    CStreamBase();
+    virtual ~CStreamBase();
+  };
+
+  class CStream final : public CStreamBase, public nsIStreamListener {
+    nsCOMPtr<nsIChannel> mChannel;
+    FallibleTArray<uint8_t> mChannelData;
+    nsresult mChannelResult;
+    bool mChannelRead;
+
+    virtual ~CStream();
+    nsresult WaitForCompletion();
+
+    // IUnknown
+    STDMETHOD(QueryInterface)(REFIID refiid, void** ppvResult) final;
+
+    // IStream
+    STDMETHODIMP Read(void* pvBuffer, ULONG nBytesToRead,
+                      ULONG* nBytesRead) final;
+    STDMETHODIMP Stat(STATSTG* statstg, DWORD dwFlags) final;
+
+   public:
+    CStream();
+    nsresult Init(nsIURI* pSourceURI, nsContentPolicyType aContentPolicyType,
+                  nsIPrincipal* aRequestingPrincipal,
+                  nsICookieJarSettings* aCookieJarSettings,
+                  nsIReferrerInfo* aReferrerInfo);
+
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIREQUESTOBSERVER
+    NS_DECL_NSISTREAMLISTENER
+  };
+
+  HRESULT CreateStream(IStream** outStream);
+
+  // This class must be thread-safe.
+  class AutoCloseEvent final {
+    const nsAutoHandle mEvent;
+
+    AutoCloseEvent(const AutoCloseEvent&) = delete;
+    void operator=(const AutoCloseEvent&) = delete;
+    ~AutoCloseEvent() = default;
+
+   public:
+    AutoCloseEvent();
+    bool IsInited() const;
+    void Signal() const;
+    DWORD Wait(DWORD aMillisec) const;
+    NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AutoCloseEvent)
+  };
+
+  // This class must be thread-safe.
+  class AutoSetEvent final {
+    const RefPtr<AutoCloseEvent> mEvent;
+
+    AutoSetEvent(const AutoSetEvent&) = delete;
+    void operator=(const AutoSetEvent&) = delete;
+    ~AutoSetEvent();
+
+   public:
+    explicit AutoSetEvent(mozilla::NotNull<AutoCloseEvent*> aEvent);
+    void Signal() const;
+    bool IsWaiting() const;
+    NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AutoSetEvent)
+  };
+
+  // This class must be thread-safe.
+  class CMemStream final : public CStreamBase {
+    static mozilla::glue::Win32SRWLock mLock;
+    const nsAutoGlobalMem mGlobalMem;
+    const RefPtr<AutoCloseEvent> mEvent;
+    const uint32_t mTotalLength;
+    RefPtr<IUnknown> mMarshaler;
+
+    virtual ~CMemStream();
+    void WaitForCompletion();
+
+    // IStream
+    STDMETHODIMP Read(void* pvBuffer, ULONG nBytesToRead,
+                      ULONG* nBytesRead) final;
+    STDMETHODIMP Stat(STATSTG* statstg, DWORD dwFlags) final;
+
+   public:
+    CMemStream(nsHGLOBAL aGlobalMem, uint32_t mTotalLength,
+               already_AddRefed<AutoCloseEvent> aEvent);
+
+    // IUnknown
+    STDMETHOD(QueryInterface)(REFIID refiid, void** ppvResult) final;
+    NS_INLINE_DECL_THREADSAFE_VIRTUAL_REFCOUNTING(CMemStream, final)
+  };
+
+ private:
+  // Drag and drop helper data for implementing drag and drop image support
+  typedef struct {
+    FORMATETC fe;
+    STGMEDIUM stgm;
+  } DATAENTRY, *LPDATAENTRY;
+
+  nsTArray<LPDATAENTRY> mDataEntryList;
+  nsCOMPtr<nsITimer> mTimer;
+
+  bool LookupArbitraryFormat(FORMATETC* aFormat, LPDATAENTRY* aDataEntry,
+                             BOOL aAddorUpdate);
+  bool CopyMediumData(STGMEDIUM* aMediumDst, STGMEDIUM* aMediumSrc,
+                      LPFORMATETC aFormat, BOOL aSetData);
+};
+
+#endif  // _NSDATAOBJ_H_
diff --git a/widget/windows/nsDataObjCollection.cpp b/widget/windows/nsDataObjCollection.cpp
new file mode 100644
index 0000000000..8750563602
--- /dev/null
+++ b/widget/windows/nsDataObjCollection.cpp
@@ -0,0 +1,370 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <shlobj.h>
+
+#include "nsDataObjCollection.h"
+#include "nsClipboard.h"
+#include "IEnumFE.h"
+
+#include <ole2.h>
+
+// {25589C3E-1FAC-47b9-BF43-CAEA89B79533}
+const IID IID_IDataObjCollection = {
+    0x25589c3e,
+    0x1fac,
+    0x47b9,
+    {0xbf, 0x43, 0xca, 0xea, 0x89, 0xb7, 0x95, 0x33}};
+
+/*
+ * Class nsDataObjCollection
+ */
+
+nsDataObjCollection::nsDataObjCollection() {}
+
+nsDataObjCollection::~nsDataObjCollection() { mDataObjects.Clear(); }
+
+// IUnknown interface methods - see iunknown.h for documentation
+STDMETHODIMP nsDataObjCollection::QueryInterface(REFIID riid, void** ppv) {
+  *ppv = nullptr;
+
+  if ((IID_IUnknown == riid) || (IID_IDataObject == riid)) {
+    *ppv = static_cast<IDataObject*>(this);
+    AddRef();
+    return NOERROR;
+  }
+
+  if (IID_IDataObjCollection == riid) {
+    *ppv = static_cast<nsIDataObjCollection*>(this);
+    AddRef();
+    return NOERROR;
+  }
+  // offer to operate asynchronously (required by nsDragService)
+  if (IID_IDataObjectAsyncCapability == riid) {
+    *ppv = static_cast<IDataObjectAsyncCapability*>(this);
+    AddRef();
+    return NOERROR;
+  }
+
+  return E_NOINTERFACE;
+}
+
+STDMETHODIMP_(ULONG) nsDataObjCollection::AddRef() { return ++m_cRef; }
+
+STDMETHODIMP_(ULONG) nsDataObjCollection::Release() {
+  if (0 != --m_cRef) return m_cRef;
+
+  delete this;
+
+  return 0;
+}
+
+// IDataObject methods
+STDMETHODIMP nsDataObjCollection::GetData(LPFORMATETC pFE, LPSTGMEDIUM pSTM) {
+  static CLIPFORMAT fileDescriptorFlavorA =
+      ::RegisterClipboardFormat(CFSTR_FILEDESCRIPTORA);
+  static CLIPFORMAT fileDescriptorFlavorW =
+      ::RegisterClipboardFormat(CFSTR_FILEDESCRIPTORW);
+  static CLIPFORMAT fileFlavor = ::RegisterClipboardFormat(CFSTR_FILECONTENTS);
+
+  switch (pFE->cfFormat) {
+    case CF_TEXT:
+    case CF_UNICODETEXT:
+      return GetText(pFE, pSTM);
+    case CF_HDROP:
+      return GetFile(pFE, pSTM);
+    default:
+      if (pFE->cfFormat == fileDescriptorFlavorA ||
+          pFE->cfFormat == fileDescriptorFlavorW) {
+        return GetFileDescriptors(pFE, pSTM);
+      }
+      if (pFE->cfFormat == fileFlavor) {
+        return GetFileContents(pFE, pSTM);
+      }
+  }
+  return GetFirstSupporting(pFE, pSTM);
+}
+
+STDMETHODIMP nsDataObjCollection::GetDataHere(LPFORMATETC pFE,
+                                              LPSTGMEDIUM pSTM) {
+  return E_FAIL;
+}
+
+// Other objects querying to see if we support a particular format
+STDMETHODIMP nsDataObjCollection::QueryGetData(LPFORMATETC pFE) {
+  UINT format = nsClipboard::GetFormat(MULTI_MIME);
+
+  if (format == pFE->cfFormat) {
+    return S_OK;
+  }
+
+  for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
+    IDataObject* dataObj = mDataObjects.ElementAt(i);
+    if (S_OK == dataObj->QueryGetData(pFE)) {
+      return S_OK;
+    }
+  }
+
+  return DV_E_FORMATETC;
+}
+
+STDMETHODIMP nsDataObjCollection::SetData(LPFORMATETC pFE, LPSTGMEDIUM pSTM,
+                                          BOOL fRelease) {
+  // Set arbitrary data formats on the first object in the collection and let
+  // it handle the heavy lifting
+  if (mDataObjects.Length() == 0) return E_FAIL;
+  return mDataObjects.ElementAt(0)->SetData(pFE, pSTM, fRelease);
+}
+
+// Registers a DataFlavor/FE pair
+void nsDataObjCollection::AddDataFlavor(const char* aDataFlavor,
+                                        LPFORMATETC aFE) {
+  // Add the FormatEtc to our list if it's not already there.  We don't care
+  // about the internal aDataFlavor because nsDataObj handles that.
+  IEnumFORMATETC* ifEtc;
+  FORMATETC fEtc;
+  ULONG num;
+  if (S_OK != this->EnumFormatEtc(DATADIR_GET, &ifEtc)) return;
+  while (S_OK == ifEtc->Next(1, &fEtc, &num)) {
+    NS_ASSERTION(
+        1 == num,
+        "Bit off more than we can chew in nsDataObjCollection::AddDataFlavor");
+    if (FormatsMatch(fEtc, *aFE)) {
+      ifEtc->Release();
+      return;
+    }
+  }  // If we didn't find a matching format, add this one
+  ifEtc->Release();
+  m_enumFE->AddFormatEtc(aFE);
+}
+
+// We accept ownership of the nsDataObj which we free on destruction
+void nsDataObjCollection::AddDataObject(IDataObject* aDataObj) {
+  nsDataObj* dataObj = reinterpret_cast<nsDataObj*>(aDataObj);
+  mDataObjects.AppendElement(dataObj);
+}
+
+// Methods for getting data
+HRESULT nsDataObjCollection::GetFile(LPFORMATETC pFE, LPSTGMEDIUM pSTM) {
+  STGMEDIUM workingmedium;
+  FORMATETC fe = *pFE;
+  HGLOBAL hGlobalMemory;
+  HRESULT hr;
+  // Make enough space for the header and the trailing null
+  uint32_t buffersize = sizeof(DROPFILES) + sizeof(char16_t);
+  uint32_t alloclen = 0;
+  char16_t* realbuffer;
+  nsAutoString filename;
+
+  hGlobalMemory = GlobalAlloc(GHND, buffersize);
+
+  for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
+    nsDataObj* dataObj = mDataObjects.ElementAt(i);
+    hr = dataObj->GetData(&fe, &workingmedium);
+    if (hr != S_OK) {
+      switch (hr) {
+        case DV_E_FORMATETC:
+          continue;
+        default:
+          return hr;
+      }
+    }
+    // Now we need to pull out the filename
+    char16_t* buffer = (char16_t*)GlobalLock(workingmedium.hGlobal);
+    if (buffer == nullptr) return E_FAIL;
+    buffer += sizeof(DROPFILES) / sizeof(char16_t);
+    filename = buffer;
+    GlobalUnlock(workingmedium.hGlobal);
+    ReleaseStgMedium(&workingmedium);
+    // Now put the filename into our buffer
+    alloclen = (filename.Length() + 1) * sizeof(char16_t);
+    hGlobalMemory = ::GlobalReAlloc(hGlobalMemory, buffersize + alloclen, GHND);
+    if (hGlobalMemory == nullptr) return E_FAIL;
+    realbuffer = (char16_t*)((char*)GlobalLock(hGlobalMemory) + buffersize);
+    if (!realbuffer) return E_FAIL;
+    realbuffer--;  // Overwrite the preceding null
+    memcpy(realbuffer, filename.get(), alloclen);
+    GlobalUnlock(hGlobalMemory);
+    buffersize += alloclen;
+  }
+  // We get the last null (on the double null terminator) for free since we used
+  // the zero memory flag when we allocated.  All we need to do is fill the
+  // DROPFILES structure
+  DROPFILES* df = (DROPFILES*)GlobalLock(hGlobalMemory);
+  if (!df) return E_FAIL;
+  df->pFiles = sizeof(DROPFILES);  // Offset to start of file name string
+  df->fNC = 0;
+  df->pt.x = 0;
+  df->pt.y = 0;
+  df->fWide = TRUE;  // utf-16 chars
+  GlobalUnlock(hGlobalMemory);
+  // Finally fill out the STGMEDIUM struct
+  pSTM->tymed = TYMED_HGLOBAL;
+  pSTM->pUnkForRelease = nullptr;  // Caller gets to free the data
+  pSTM->hGlobal = hGlobalMemory;
+  return S_OK;
+}
+
+HRESULT nsDataObjCollection::GetText(LPFORMATETC pFE, LPSTGMEDIUM pSTM) {
+  STGMEDIUM workingmedium;
+  FORMATETC fe = *pFE;
+  HGLOBAL hGlobalMemory;
+  HRESULT hr;
+  uint32_t buffersize = 1;
+  uint32_t alloclen = 0;
+
+  hGlobalMemory = GlobalAlloc(GHND, buffersize);
+
+  if (pFE->cfFormat == CF_TEXT) {
+    nsAutoCString text;
+    for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
+      nsDataObj* dataObj = mDataObjects.ElementAt(i);
+      hr = dataObj->GetData(&fe, &workingmedium);
+      if (hr != S_OK) {
+        switch (hr) {
+          case DV_E_FORMATETC:
+            continue;
+          default:
+            return hr;
+        }
+      }
+      // Now we need to pull out the text
+      char* buffer = (char*)GlobalLock(workingmedium.hGlobal);
+      if (buffer == nullptr) return E_FAIL;
+      text = buffer;
+      GlobalUnlock(workingmedium.hGlobal);
+      ReleaseStgMedium(&workingmedium);
+      // Now put the text into our buffer
+      alloclen = text.Length();
+      hGlobalMemory =
+          ::GlobalReAlloc(hGlobalMemory, buffersize + alloclen, GHND);
+      if (hGlobalMemory == nullptr) return E_FAIL;
+      buffer = ((char*)GlobalLock(hGlobalMemory) + buffersize);
+      if (!buffer) return E_FAIL;
+      buffer--;  // Overwrite the preceding null
+      memcpy(buffer, text.get(), alloclen);
+      GlobalUnlock(hGlobalMemory);
+      buffersize += alloclen;
+    }
+    pSTM->tymed = TYMED_HGLOBAL;
+    pSTM->pUnkForRelease = nullptr;  // Caller gets to free the data
+    pSTM->hGlobal = hGlobalMemory;
+    return S_OK;
+  }
+  if (pFE->cfFormat == CF_UNICODETEXT) {
+    buffersize = sizeof(char16_t);
+    nsAutoString text;
+    for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
+      nsDataObj* dataObj = mDataObjects.ElementAt(i);
+      hr = dataObj->GetData(&fe, &workingmedium);
+      if (hr != S_OK) {
+        switch (hr) {
+          case DV_E_FORMATETC:
+            continue;
+          default:
+            return hr;
+        }
+      }
+      // Now we need to pull out the text
+      char16_t* buffer = (char16_t*)GlobalLock(workingmedium.hGlobal);
+      if (buffer == nullptr) return E_FAIL;
+      text = buffer;
+      GlobalUnlock(workingmedium.hGlobal);
+      ReleaseStgMedium(&workingmedium);
+      // Now put the text into our buffer
+      alloclen = text.Length() * sizeof(char16_t);
+      hGlobalMemory =
+          ::GlobalReAlloc(hGlobalMemory, buffersize + alloclen, GHND);
+      if (hGlobalMemory == nullptr) return E_FAIL;
+      buffer = (char16_t*)((char*)GlobalLock(hGlobalMemory) + buffersize);
+      if (!buffer) return E_FAIL;
+      buffer--;  // Overwrite the preceding null
+      memcpy(buffer, text.get(), alloclen);
+      GlobalUnlock(hGlobalMemory);
+      buffersize += alloclen;
+    }
+    pSTM->tymed = TYMED_HGLOBAL;
+    pSTM->pUnkForRelease = nullptr;  // Caller gets to free the data
+    pSTM->hGlobal = hGlobalMemory;
+    return S_OK;
+  }
+
+  return E_FAIL;
+}
+
+HRESULT nsDataObjCollection::GetFileDescriptors(LPFORMATETC pFE,
+                                                LPSTGMEDIUM pSTM) {
+  STGMEDIUM workingmedium;
+  FORMATETC fe = *pFE;
+  HGLOBAL hGlobalMemory;
+  HRESULT hr;
+  uint32_t buffersize = sizeof(UINT);
+  uint32_t alloclen = sizeof(FILEDESCRIPTOR);
+
+  hGlobalMemory = GlobalAlloc(GHND, buffersize);
+
+  for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
+    nsDataObj* dataObj = mDataObjects.ElementAt(i);
+    hr = dataObj->GetData(&fe, &workingmedium);
+    if (hr != S_OK) {
+      switch (hr) {
+        case DV_E_FORMATETC:
+          continue;
+        default:
+          return hr;
+      }
+    }
+    // Now we need to pull out the filedescriptor
+    FILEDESCRIPTOR* buffer =
+        (FILEDESCRIPTOR*)((char*)GlobalLock(workingmedium.hGlobal) +
+                          sizeof(UINT));
+    if (buffer == nullptr) return E_FAIL;
+    hGlobalMemory = ::GlobalReAlloc(hGlobalMemory, buffersize + alloclen, GHND);
+    if (hGlobalMemory == nullptr) return E_FAIL;
+    FILEGROUPDESCRIPTOR* realbuffer =
+        (FILEGROUPDESCRIPTOR*)GlobalLock(hGlobalMemory);
+    if (!realbuffer) return E_FAIL;
+    FILEDESCRIPTOR* copyloc = (FILEDESCRIPTOR*)((char*)realbuffer + buffersize);
+    memcpy(copyloc, buffer, alloclen);
+    realbuffer->cItems++;
+    GlobalUnlock(hGlobalMemory);
+    GlobalUnlock(workingmedium.hGlobal);
+    ReleaseStgMedium(&workingmedium);
+    buffersize += alloclen;
+  }
+  pSTM->tymed = TYMED_HGLOBAL;
+  pSTM->pUnkForRelease = nullptr;  // Caller gets to free the data
+  pSTM->hGlobal = hGlobalMemory;
+  return S_OK;
+}
+
+HRESULT nsDataObjCollection::GetFileContents(LPFORMATETC pFE,
+                                             LPSTGMEDIUM pSTM) {
+  ULONG num = 0;
+  ULONG numwanted = (pFE->lindex == -1) ? 0 : pFE->lindex;
+  FORMATETC fEtc = *pFE;
+  fEtc.lindex = -1;  // We're lying to the data object so it thinks it's alone
+
+  // The key for this data type is to figure out which data object the index
+  // corresponds to and then just pass it along
+  for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
+    nsDataObj* dataObj = mDataObjects.ElementAt(i);
+    if (dataObj->QueryGetData(&fEtc) != S_OK) continue;
+    if (num == numwanted) return dataObj->GetData(pFE, pSTM);
+    num++;
+  }
+  return DV_E_LINDEX;
+}
+
+HRESULT nsDataObjCollection::GetFirstSupporting(LPFORMATETC pFE,
+                                                LPSTGMEDIUM pSTM) {
+  // There is no way to pass more than one of this, so just find the first data
+  // object that supports it and pass it along
+  for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
+    if (mDataObjects.ElementAt(i)->QueryGetData(pFE) == S_OK)
+      return mDataObjects.ElementAt(i)->GetData(pFE, pSTM);
+  }
+  return DV_E_FORMATETC;
+}
diff --git a/widget/windows/nsDataObjCollection.h b/widget/windows/nsDataObjCollection.h
new file mode 100644
index 0000000000..02ec7e8916
--- /dev/null
+++ b/widget/windows/nsDataObjCollection.h
@@ -0,0 +1,92 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _NSDATAOBJCOLLECTION_H_
+#define _NSDATAOBJCOLLECTION_H_
+
+#include <oleidl.h>
+
+#include "mozilla/RefPtr.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "nsDataObj.h"
+#include "mozilla/Attributes.h"
+
+#define MULTI_MIME "Mozilla/IDataObjectCollectionFormat"
+
+EXTERN_C const IID IID_IDataObjCollection;
+
+// An interface to make sure we have the right kind of object for D&D
+// this way we can filter out collection objects that aren't ours
+class nsIDataObjCollection : public IUnknown {
+ public:
+};
+
+/*
+ * This ole registered class is used to facilitate drag-drop of objects which
+ * can be adapted by an object derived from CfDragDrop. The CfDragDrop is
+ * associated with instances via SetDragDrop().
+ */
+
+class nsDataObjCollection final : public nsIDataObjCollection,
+                                  public nsDataObj {
+ public:
+  nsDataObjCollection();
+
+ private:
+  ~nsDataObjCollection() final;
+
+ public:  // IUnknown methods - see iunknown.h for documentation
+  STDMETHODIMP_(ULONG) AddRef() final;
+  STDMETHODIMP QueryInterface(REFIID, void**) final;
+  STDMETHODIMP_(ULONG) Release() final;
+
+ private:  // DataGet and DataSet helper methods
+  HRESULT GetFile(LPFORMATETC pFE, LPSTGMEDIUM pSTM);
+  HRESULT GetText(LPFORMATETC pFE, LPSTGMEDIUM pSTM);
+  HRESULT GetFileDescriptors(LPFORMATETC pFE, LPSTGMEDIUM pSTM);
+  HRESULT GetFileContents(LPFORMATETC pFE, LPSTGMEDIUM pSTM);
+  HRESULT GetFirstSupporting(LPFORMATETC pFE, LPSTGMEDIUM pSTM);
+
+  using nsDataObj::GetFile;
+  using nsDataObj::GetFileContents;
+  using nsDataObj::GetText;
+
+  // support for clipboard
+  void AddDataFlavor(const char* aDataFlavor, LPFORMATETC aFE) final;
+
+ public:  // from nsPIDataObjCollection
+  void AddDataObject(IDataObject* aDataObj);
+  int32_t GetNumDataObjects() { return mDataObjects.Length(); }
+  nsDataObj* GetDataObjectAt(uint32_t aItem) {
+    return mDataObjects.SafeElementAt(aItem, RefPtr<nsDataObj>());
+  }
+
+ public:
+  // Store data in pSTM according to the format specified by pFE, if the
+  // format is supported (supported formats are specified in CfDragDrop::
+  // GetFormats) and return NOERROR; otherwise return DATA_E_FORMATETC. It
+  // is the callers responsibility to free pSTM if NOERROR is returned.
+  STDMETHODIMP GetData(LPFORMATETC pFE, LPSTGMEDIUM pSTM) final;
+
+  // Similar to GetData except that the caller allocates the structure
+  // referenced by pSTM.
+  STDMETHODIMP GetDataHere(LPFORMATETC pFE, LPSTGMEDIUM pSTM) final;
+
+  // Returns S_TRUE if this object supports the format specified by pSTM,
+  // S_FALSE otherwise.
+  STDMETHODIMP QueryGetData(LPFORMATETC pFE) final;
+
+  // Set this objects data according to the format specified by pFE and
+  // the storage medium specified by pSTM and return NOERROR, if the format
+  // is supported. If release is TRUE this object must release the storage
+  // associated with pSTM.
+  STDMETHODIMP SetData(LPFORMATETC pFE, LPSTGMEDIUM pSTM, BOOL release) final;
+
+ private:
+  nsTArray<RefPtr<nsDataObj> > mDataObjects;
+};
+
+#endif  //
diff --git a/widget/windows/nsDeviceContextSpecWin.cpp b/widget/windows/nsDeviceContextSpecWin.cpp
new file mode 100644
index 0000000000..ac3bf6f6ed
--- /dev/null
+++ b/widget/windows/nsDeviceContextSpecWin.cpp
@@ -0,0 +1,680 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsDeviceContextSpecWin.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/gfx/PrintPromise.h"
+#include "mozilla/gfx/PrintTargetPDF.h"
+#include "mozilla/gfx/PrintTargetWindows.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/Telemetry.h"
+#include "nsAnonymousTemporaryFile.h"
+
+#include <wchar.h>
+#include <windef.h>
+#include <winspool.h>
+
+#include "nsIWidget.h"
+
+#include "nsTArray.h"
+#include "nsIPrintSettingsWin.h"
+
+#include "nsComponentManagerUtils.h"
+#include "nsPrinterWin.h"
+#include "nsReadableUtils.h"
+#include "nsString.h"
+
+#include "gfxWindowsSurface.h"
+
+#include "nsIFileStreams.h"
+#include "nsWindowsHelpers.h"
+
+#include "mozilla/gfx/Logging.h"
+
+#ifdef MOZ_ENABLE_SKIA_PDF
+#  include "mozilla/gfx/PrintTargetSkPDF.h"
+#  include "mozilla/gfx/PrintTargetEMF.h"
+#  include "nsIUUIDGenerator.h"
+#  include "nsDirectoryServiceDefs.h"
+#  include "nsPrintfCString.h"
+#  include "nsThreadUtils.h"
+#endif
+
+extern mozilla::LazyLogModule gPrintingLog;
+#define PR_PL(_p1) MOZ_LOG(gPrintingLog, mozilla::LogLevel::Debug, _p1)
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+
+#ifdef MOZ_ENABLE_SKIA_PDF
+using namespace mozilla::widget;
+#endif
+
+static const wchar_t kDriverName[] = L"WINSPOOL";
+
+//----------------------------------------------------------------------------------
+//---------------
+// static members
+//----------------------------------------------------------------------------------
+nsDeviceContextSpecWin::nsDeviceContextSpecWin() = default;
+
+//----------------------------------------------------------------------------------
+
+NS_IMPL_ISUPPORTS(nsDeviceContextSpecWin, nsIDeviceContextSpec)
+
+nsDeviceContextSpecWin::~nsDeviceContextSpecWin() {
+  SetDevMode(nullptr);
+
+  if (mTempFile) {
+    mTempFile->Remove(/* recursive = */ false);
+  }
+
+  if (nsCOMPtr<nsIPrintSettingsWin> ps = do_QueryInterface(mPrintSettings)) {
+    ps->SetDeviceName(u""_ns);
+    ps->SetDriverName(u""_ns);
+    ps->SetDevMode(nullptr);
+  }
+}
+
+static bool GetDefaultPrinterName(nsAString& aDefaultPrinterName) {
+  DWORD length = 0;
+  GetDefaultPrinterW(nullptr, &length);
+
+  if (length) {
+    aDefaultPrinterName.SetLength(length);
+    if (GetDefaultPrinterW((LPWSTR)aDefaultPrinterName.BeginWriting(),
+                           &length)) {
+      // `length` includes the terminating null, so we subtract that from our
+      // string length.
+      aDefaultPrinterName.SetLength(length - 1);
+      PR_PL(("DEFAULT PRINTER [%s]\n",
+             NS_ConvertUTF16toUTF8(aDefaultPrinterName).get()));
+      return true;
+    }
+  }
+
+  aDefaultPrinterName.Truncate();
+  PR_PL(("NO DEFAULT PRINTER\n"));
+  return false;
+}
+
+//----------------------------------------------------------------------------------
+NS_IMETHODIMP nsDeviceContextSpecWin::Init(nsIPrintSettings* aPrintSettings,
+                                           bool aIsPrintPreview) {
+  mPrintSettings = aPrintSettings;
+
+  // Get the Printer Name to be used and output format.
+  nsAutoString printerName;
+  if (mPrintSettings) {
+    mOutputFormat = mPrintSettings->GetOutputFormat();
+    mPrintSettings->GetPrinterName(printerName);
+  }
+
+  // If there is no name then use the default printer
+  if (printerName.IsEmpty()) {
+    GetDefaultPrinterName(printerName);
+  }
+
+  // Gather telemetry on the print target type.
+  //
+  // Unfortunately, if we're not using our own internal save-to-pdf codepaths,
+  // there isn't a good way to determine whether a print is going to be to a
+  // physical printer or to a file or some other non-physical output. We do our
+  // best by checking for what seems to be the most common save-to-PDF virtual
+  // printers.
+  //
+  // We use StringBeginsWith below, since printer names are often followed by a
+  // version number or other product differentiating string.  (True for doPDF,
+  // novaPDF, PDF-XChange and Soda PDF, for example.)
+  if (mOutputFormat == nsIPrintSettings::kOutputFormatPDF) {
+    Telemetry::ScalarAdd(Telemetry::ScalarID::PRINTING_TARGET_TYPE,
+                         u"pdf_file"_ns, 1);
+  } else if (StringBeginsWith(printerName, u"Microsoft Print to PDF"_ns) ||
+             StringBeginsWith(printerName, u"Adobe PDF"_ns) ||
+             StringBeginsWith(printerName, u"Bullzip PDF Printer"_ns) ||
+             StringBeginsWith(printerName, u"CutePDF Writer"_ns) ||
+             StringBeginsWith(printerName, u"doPDF"_ns) ||
+             StringBeginsWith(printerName, u"Foxit Reader PDF Printer"_ns) ||
+             StringBeginsWith(printerName, u"Nitro PDF Creator"_ns) ||
+             StringBeginsWith(printerName, u"novaPDF"_ns) ||
+             StringBeginsWith(printerName, u"PDF-XChange"_ns) ||
+             StringBeginsWith(printerName, u"PDF24 PDF"_ns) ||
+             StringBeginsWith(printerName, u"PDFCreator"_ns) ||
+             StringBeginsWith(printerName, u"PrimoPDF"_ns) ||
+             StringBeginsWith(printerName, u"Soda PDF"_ns) ||
+             StringBeginsWith(printerName, u"Solid PDF Creator"_ns) ||
+             StringBeginsWith(printerName,
+                              u"Universal Document Converter"_ns)) {
+    Telemetry::ScalarAdd(Telemetry::ScalarID::PRINTING_TARGET_TYPE,
+                         u"pdf_file"_ns, 1);
+  } else if (printerName.EqualsLiteral("Microsoft XPS Document Writer")) {
+    Telemetry::ScalarAdd(Telemetry::ScalarID::PRINTING_TARGET_TYPE,
+                         u"xps_file"_ns, 1);
+  } else {
+    nsAString::const_iterator start, end;
+    printerName.BeginReading(start);
+    printerName.EndReading(end);
+    if (CaseInsensitiveFindInReadable(u"pdf"_ns, start, end)) {
+      Telemetry::ScalarAdd(Telemetry::ScalarID::PRINTING_TARGET_TYPE,
+                           u"pdf_unknown"_ns, 1);
+    } else {
+      Telemetry::ScalarAdd(Telemetry::ScalarID::PRINTING_TARGET_TYPE,
+                           u"unknown"_ns, 1);
+    }
+  }
+
+  nsresult rv = NS_ERROR_GFX_PRINTER_NO_PRINTER_AVAILABLE;
+  if (aPrintSettings) {
+#ifdef MOZ_ENABLE_SKIA_PDF
+    nsAutoString printViaPdf;
+    Preferences::GetString("print.print_via_pdf_encoder", printViaPdf);
+    if (printViaPdf.EqualsLiteral("skia-pdf")) {
+      mPrintViaSkPDF = true;
+    }
+#endif
+
+    // If we're in the child or we're printing to PDF we only need information
+    // from the print settings.
+    if (XRE_IsContentProcess() ||
+        mOutputFormat == nsIPrintSettings::kOutputFormatPDF) {
+      return NS_OK;
+    }
+
+    nsCOMPtr<nsIPrintSettingsWin> psWin(do_QueryInterface(aPrintSettings));
+    if (psWin) {
+      nsAutoString deviceName;
+      nsAutoString driverName;
+      psWin->GetDeviceName(deviceName);
+      psWin->GetDriverName(driverName);
+
+      LPDEVMODEW devMode;
+      psWin->GetDevMode(&devMode);  // creates new memory (makes a copy)
+
+      if (!deviceName.IsEmpty() && !driverName.IsEmpty() && devMode) {
+        // Scaling is special, it is one of the few
+        // devMode items that we control in layout
+        if (devMode->dmFields & DM_SCALE) {
+          double scale = double(devMode->dmScale) / 100.0f;
+          if (scale != 1.0) {
+            aPrintSettings->SetScaling(scale);
+            devMode->dmScale = 100;
+          }
+        }
+
+        SetDeviceName(deviceName);
+        SetDriverName(driverName);
+        SetDevMode(devMode);
+
+        return NS_OK;
+      } else {
+        PR_PL(
+            ("***** nsDeviceContextSpecWin::Init - "
+             "deviceName/driverName/devMode was NULL!\n"));
+        if (devMode) ::HeapFree(::GetProcessHeap(), 0, devMode);
+      }
+    }
+  } else {
+    PR_PL(("***** nsDeviceContextSpecWin::Init - aPrintSettingswas NULL!\n"));
+  }
+
+  if (printerName.IsEmpty()) {
+    return rv;
+  }
+
+  return GetDataFromPrinter(printerName, mPrintSettings);
+}
+
+//----------------------------------------------------------
+
+already_AddRefed<PrintTarget> nsDeviceContextSpecWin::MakePrintTarget() {
+  NS_ASSERTION(mDevMode || mOutputFormat == nsIPrintSettings::kOutputFormatPDF,
+               "DevMode can't be NULL here unless we're printing to PDF.");
+
+#ifdef MOZ_ENABLE_SKIA_PDF
+  if (mPrintViaSkPDF) {
+    double width, height;
+    mPrintSettings->GetEffectivePageSize(&width, &height);
+    if (width <= 0 || height <= 0) {
+      return nullptr;
+    }
+
+    // convert twips to points
+    width /= TWIPS_PER_POINT_FLOAT;
+    height /= TWIPS_PER_POINT_FLOAT;
+    IntSize size = IntSize::Ceil(width, height);
+
+    if (mOutputFormat == nsIPrintSettings::kOutputFormatPDF) {
+      nsString filename;
+      // TODO(dshin):
+      // - Does this handle bug 1659470?
+      // - Should this code path be enabled, we should use temporary files and
+      // then move the file in `EndDocument()`.
+      mPrintSettings->GetToFileName(filename);
+
+      nsAutoCString printFile(NS_ConvertUTF16toUTF8(filename).get());
+      auto skStream = MakeUnique<SkFILEWStream>(printFile.get());
+      return PrintTargetSkPDF::CreateOrNull(std::move(skStream), size);
+    }
+
+    if (mDevMode) {
+      NS_WARNING_ASSERTION(!mDriverName.IsEmpty(), "No driver!");
+      HDC dc =
+          ::CreateDCW(mDriverName.get(), mDeviceName.get(), nullptr, mDevMode);
+      if (!dc) {
+        gfxCriticalError(gfxCriticalError::DefaultOptions(false))
+            << "Failed to create device context in GetSurfaceForPrinter";
+        return nullptr;
+      }
+      return PrintTargetEMF::CreateOrNull(dc, size);
+    }
+  }
+#endif
+
+  if (mOutputFormat == nsIPrintSettings::kOutputFormatPDF) {
+    double width, height;
+    mPrintSettings->GetEffectiveSheetSize(&width, &height);
+    if (width <= 0 || height <= 0) {
+      return nullptr;
+    }
+
+    // convert twips to points
+    width /= TWIPS_PER_POINT_FLOAT;
+    height /= TWIPS_PER_POINT_FLOAT;
+
+    auto stream = [&]() -> nsCOMPtr<nsIOutputStream> {
+      if (mPrintSettings->GetOutputDestination() ==
+          nsIPrintSettings::kOutputDestinationStream) {
+        nsCOMPtr<nsIOutputStream> out;
+        mPrintSettings->GetOutputStream(getter_AddRefs(out));
+        return out;
+      }
+
+      // Even if the destination may be a named path, write to a temp file -
+      // this is consistent with behaviour of `PrintTarget` on other platforms.
+      nsCOMPtr<nsIFile> file;
+      nsresult rv = NS_OpenAnonymousTemporaryNsIFile(getter_AddRefs(mTempFile));
+      file = mTempFile;
+
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return nullptr;
+      }
+
+      nsCOMPtr<nsIFileOutputStream> stream =
+          do_CreateInstance("@mozilla.org/network/file-output-stream;1");
+      if (NS_FAILED(stream->Init(file, -1, -1, 0))) {
+        return nullptr;
+      }
+      return stream;
+    }();
+
+    return PrintTargetPDF::CreateOrNull(stream, IntSize::Ceil(width, height));
+  }
+
+  if (mDevMode) {
+    NS_WARNING_ASSERTION(!mDriverName.IsEmpty(), "No driver!");
+    HDC dc =
+        ::CreateDCW(mDriverName.get(), mDeviceName.get(), nullptr, mDevMode);
+    if (!dc) {
+      gfxCriticalError(gfxCriticalError::DefaultOptions(false))
+          << "Failed to create device context in GetSurfaceForPrinter";
+      return nullptr;
+    }
+
+    // The PrintTargetWindows takes over ownership of this DC
+    return PrintTargetWindows::CreateOrNull(dc);
+  }
+
+  return nullptr;
+}
+
+RefPtr<PrintEndDocumentPromise> nsDeviceContextSpecWin::EndDocument() {
+  if (mPrintSettings->GetOutputDestination() !=
+          nsIPrintSettings::kOutputDestinationFile ||
+      mOutputFormat != nsIPrintSettings::kOutputFormatPDF) {
+    return PrintEndDocumentPromise::CreateAndResolve(true, __func__);
+  }
+
+#ifdef MOZ_ENABLE_SKIA_PDF
+  if (mPrintViaSkPDF) {
+    return PrintEndDocumentPromise::CreateAndResolve(true, __func__);
+  }
+#endif
+
+  MOZ_ASSERT(mTempFile, "No handle to temporary PDF file.");
+
+  nsAutoString targetPath;
+  mPrintSettings->GetToFileName(targetPath);
+
+  if (targetPath.IsEmpty()) {
+    return PrintEndDocumentPromise::CreateAndResolve(true, __func__);
+  }
+
+  // We still need to move the file to its actual destination.
+  nsCOMPtr<nsIFile> destFile;
+  auto rv = NS_NewLocalFile(targetPath, false, getter_AddRefs(destFile));
+  if (NS_FAILED(rv)) {
+    return PrintEndDocumentPromise::CreateAndReject(rv, __func__);
+  }
+
+  return nsIDeviceContextSpec::EndDocumentAsync(
+      __func__,
+      [destFile = std::move(destFile),
+       tempFile = std::move(mTempFile)]() -> nsresult {
+        nsAutoString destLeafName;
+        MOZ_TRY(destFile->GetLeafName(destLeafName));
+
+        nsCOMPtr<nsIFile> destDir;
+        MOZ_TRY(destFile->GetParent(getter_AddRefs(destDir)));
+
+        // This should be fine - Windows API calls usually prevent moving
+        // between different volumes (See Win32 API's `MOVEFILE_COPY_ALLOWED`
+        // flag), but we handle that down this call.
+        MOZ_TRY(tempFile->MoveTo(destDir, destLeafName));
+        return NS_OK;
+      });
+}
+
+//----------------------------------------------------------------------------------
+void nsDeviceContextSpecWin::SetDeviceName(const nsAString& aDeviceName) {
+  mDeviceName = aDeviceName;
+}
+
+//----------------------------------------------------------------------------------
+void nsDeviceContextSpecWin::SetDriverName(const nsAString& aDriverName) {
+  mDriverName = aDriverName;
+}
+
+//----------------------------------------------------------------------------------
+void nsDeviceContextSpecWin::SetDevMode(LPDEVMODEW aDevMode) {
+  if (mDevMode) {
+    ::HeapFree(::GetProcessHeap(), 0, mDevMode);
+  }
+
+  mDevMode = aDevMode;
+}
+
+//------------------------------------------------------------------
+void nsDeviceContextSpecWin::GetDevMode(LPDEVMODEW& aDevMode) {
+  aDevMode = mDevMode;
+}
+
+#define DISPLAY_LAST_ERROR
+
+//----------------------------------------------------------------------------------
+// Setup the object's data member with the selected printer's data
+nsresult nsDeviceContextSpecWin::GetDataFromPrinter(const nsAString& aName,
+                                                    nsIPrintSettings* aPS) {
+  nsresult rv = NS_ERROR_FAILURE;
+
+  nsHPRINTER hPrinter = nullptr;
+  const nsString& flat = PromiseFlatString(aName);
+  wchar_t* name =
+      (wchar_t*)flat.get();  // Windows APIs use non-const name argument
+
+  BOOL status = ::OpenPrinterW(name, &hPrinter, nullptr);
+  if (status) {
+    nsAutoPrinter autoPrinter(hPrinter);
+
+    LPDEVMODEW pDevMode;
+
+    // Allocate a buffer of the correct size.
+    LONG needed =
+        ::DocumentPropertiesW(nullptr, hPrinter, name, nullptr, nullptr, 0);
+    if (needed < 0) {
+      PR_PL(
+          ("**** nsDeviceContextSpecWin::GetDataFromPrinter - Couldn't get "
+           "size of DEVMODE using DocumentPropertiesW(pDeviceName = \"%s\"). "
+           "GetLastEror() = %08lx\n",
+           NS_ConvertUTF16toUTF8(aName).get(), GetLastError()));
+      return NS_ERROR_FAILURE;
+    }
+
+    // Some drivers do not return the correct size for their DEVMODE, so we
+    // over-allocate to try and compensate.
+    // (See https://bugzilla.mozilla.org/show_bug.cgi?id=1664530#c5)
+    needed *= 2;
+    pDevMode =
+        (LPDEVMODEW)::HeapAlloc(::GetProcessHeap(), HEAP_ZERO_MEMORY, needed);
+    if (!pDevMode) return NS_ERROR_FAILURE;
+
+    // Get the default DevMode for the printer and modify it for our needs.
+    LONG ret = ::DocumentPropertiesW(nullptr, hPrinter, name, pDevMode, nullptr,
+                                     DM_OUT_BUFFER);
+
+    if (ret == IDOK && aPS) {
+      nsCOMPtr<nsIPrintSettingsWin> psWin = do_QueryInterface(aPS);
+      MOZ_ASSERT(psWin);
+      psWin->CopyToNative(pDevMode);
+      // Sets back the changes we made to the DevMode into the Printer Driver
+      ret = ::DocumentPropertiesW(nullptr, hPrinter, name, pDevMode, pDevMode,
+                                  DM_IN_BUFFER | DM_OUT_BUFFER);
+
+      // We need to copy the final DEVMODE settings back to our print settings,
+      // because they may have been set from invalid prefs.
+      if (ret == IDOK) {
+        // We need to get information from the device as well.
+        nsAutoHDC printerDC(::CreateICW(kDriverName, name, nullptr, pDevMode));
+        if (NS_WARN_IF(!printerDC)) {
+          ::HeapFree(::GetProcessHeap(), 0, pDevMode);
+          return NS_ERROR_FAILURE;
+        }
+
+        psWin->CopyFromNative(printerDC, pDevMode);
+      }
+    }
+
+    if (ret != IDOK) {
+      ::HeapFree(::GetProcessHeap(), 0, pDevMode);
+      PR_PL(
+          ("***** nsDeviceContextSpecWin::GetDataFromPrinter - "
+           "DocumentProperties call failed code: %ld/0x%lx\n",
+           ret, ret));
+      DISPLAY_LAST_ERROR
+      return NS_ERROR_FAILURE;
+    }
+
+    SetDevMode(
+        pDevMode);  // cache the pointer and takes responsibility for the memory
+
+    SetDeviceName(aName);
+
+    SetDriverName(nsDependentString(kDriverName));
+
+    rv = NS_OK;
+  } else {
+    rv = NS_ERROR_GFX_PRINTER_NAME_NOT_FOUND;
+    PR_PL(
+        ("***** nsDeviceContextSpecWin::GetDataFromPrinter - Couldn't open "
+         "printer: [%s]\n",
+         NS_ConvertUTF16toUTF8(aName).get()));
+    DISPLAY_LAST_ERROR
+  }
+  return rv;
+}
+
+//***********************************************************
+//  Printer List
+//***********************************************************
+
+nsPrinterListWin::~nsPrinterListWin() = default;
+
+// Helper to get the array of PRINTER_INFO_4 records from the OS into a
+// caller-supplied byte array; returns the number of records present.
+static unsigned GetPrinterInfo4(nsTArray<BYTE>& aBuffer) {
+  const DWORD kLevel = 4;
+  DWORD needed = 0;
+  DWORD count = 0;
+  const DWORD kFlags = PRINTER_ENUM_LOCAL | PRINTER_ENUM_CONNECTIONS;
+  BOOL ok = ::EnumPrintersW(kFlags,
+                            nullptr,  // Name
+                            kLevel,   // Level
+                            nullptr,  // pPrinterEnum
+                            0,        // cbBuf (buffer size)
+                            &needed,  // Bytes needed in buffer
+                            &count);
+  if (needed > 0) {
+    if (!aBuffer.SetLength(needed, fallible)) {
+      return 0;
+    }
+    ok = ::EnumPrintersW(kFlags, nullptr, kLevel, aBuffer.Elements(),
+                         aBuffer.Length(), &needed, &count);
+  }
+  if (!ok) {
+    return 0;
+  }
+  return count;
+}
+
+nsTArray<nsPrinterListBase::PrinterInfo> nsPrinterListWin::Printers() const {
+  PR_PL(("nsPrinterListWin::Printers\n"));
+
+  AutoTArray<BYTE, 1024> buffer;
+  unsigned count = GetPrinterInfo4(buffer);
+
+  if (!count) {
+    PR_PL(("[No printers found]\n"));
+    return {};
+  }
+
+  const auto* printers =
+      reinterpret_cast<const _PRINTER_INFO_4W*>(buffer.Elements());
+  nsTArray<PrinterInfo> list;
+  for (unsigned i = 0; i < count; i++) {
+    // For LOCAL printers, we check whether OpenPrinter succeeds, and omit
+    // them from the list if not. This avoids presenting printers that the
+    // user cannot actually use (e.g. due to Windows permissions).
+    // For NETWORK printers, this check may block for a long time (waiting for
+    // network timeout), so we skip it; if the user tries to access a printer
+    // that isn't available, we'll have to show an error later.
+    // (We always need to be able to handle an error, anyhow, as the printer
+    // could get disconnected after we've created the list, for example.)
+    bool isAvailable = false;
+    if (printers[i].Attributes & PRINTER_ATTRIBUTE_NETWORK) {
+      isAvailable = true;
+    } else if (printers[i].Attributes & PRINTER_ATTRIBUTE_LOCAL) {
+      HANDLE handle;
+      if (::OpenPrinterW(printers[i].pPrinterName, &handle, nullptr)) {
+        ::ClosePrinter(handle);
+        isAvailable = true;
+      }
+    }
+    if (isAvailable) {
+      list.AppendElement(PrinterInfo{nsString(printers[i].pPrinterName)});
+      PR_PL(("Printer Name: %s\n",
+             NS_ConvertUTF16toUTF8(printers[i].pPrinterName).get()));
+    }
+  }
+
+  if (list.IsEmpty()) {
+    PR_PL(("[No usable printers found]\n"));
+    return {};
+  }
+
+  list.Sort([](const PrinterInfo& a, const PrinterInfo& b) {
+    size_t len = std::min(a.mName.Length(), b.mName.Length());
+    int result = CaseInsensitiveCompare(a.mName.BeginReading(),
+                                        b.mName.BeginReading(), len);
+    return result ? result : int(a.mName.Length()) - int(b.mName.Length());
+  });
+
+  return list;
+}
+
+Maybe<nsPrinterListBase::PrinterInfo> nsPrinterListWin::PrinterByName(
+    nsString aName) const {
+  Maybe<PrinterInfo> rv;
+
+  AutoTArray<BYTE, 1024> buffer;
+  unsigned count = GetPrinterInfo4(buffer);
+
+  const auto* printers =
+      reinterpret_cast<const _PRINTER_INFO_4W*>(buffer.Elements());
+  for (unsigned i = 0; i < count; ++i) {
+    if (aName.Equals(nsString(printers[i].pPrinterName))) {
+      rv.emplace(PrinterInfo{aName});
+      break;
+    }
+  }
+
+  return rv;
+}
+
+Maybe<nsPrinterListBase::PrinterInfo> nsPrinterListWin::PrinterBySystemName(
+    nsString aName) const {
+  return PrinterByName(std::move(aName));
+}
+
+RefPtr<nsIPrinter> nsPrinterListWin::CreatePrinter(PrinterInfo aInfo) const {
+  return nsPrinterWin::Create(mCommonPaperInfo, std::move(aInfo.mName));
+}
+
+nsresult nsPrinterListWin::SystemDefaultPrinterName(nsAString& aName) const {
+  if (!GetDefaultPrinterName(aName)) {
+    NS_WARNING("Uh oh, GetDefaultPrinterName failed");
+    // Indicate failure by leaving aName untouched, i.e. the empty string.
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrinterListWin::InitPrintSettingsFromPrinter(
+    const nsAString& aPrinterName, nsIPrintSettings* aPrintSettings) {
+  NS_ENSURE_ARG_POINTER(aPrintSettings);
+
+  if (aPrinterName.IsEmpty()) {
+    return NS_OK;
+  }
+
+  // When printing to PDF on Windows there is no associated printer driver.
+  int16_t outputFormat = aPrintSettings->GetOutputFormat();
+  if (outputFormat == nsIPrintSettings::kOutputFormatPDF) {
+    return NS_OK;
+  }
+
+  RefPtr<nsDeviceContextSpecWin> devSpecWin = new nsDeviceContextSpecWin();
+  if (!devSpecWin) return NS_ERROR_OUT_OF_MEMORY;
+
+  // If the settings have already been initialized from prefs then pass these to
+  // GetDataFromPrinter, so that they are saved to the printer.
+  bool initializedFromPrefs;
+  nsresult rv =
+      aPrintSettings->GetIsInitializedFromPrefs(&initializedFromPrefs);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  if (initializedFromPrefs) {
+    // If we pass in print settings to GetDataFromPrinter it already copies
+    // things back to the settings, so we can return here.
+    return devSpecWin->GetDataFromPrinter(aPrinterName, aPrintSettings);
+  }
+
+  devSpecWin->GetDataFromPrinter(aPrinterName);
+
+  LPDEVMODEW devmode;
+  devSpecWin->GetDevMode(devmode);
+  if (NS_WARN_IF(!devmode)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  aPrintSettings->SetPrinterName(aPrinterName);
+
+  // We need to get information from the device as well.
+  const nsString& flat = PromiseFlatString(aPrinterName);
+  char16ptr_t printerName = flat.get();
+  HDC dc = ::CreateICW(kDriverName, printerName, nullptr, devmode);
+  if (NS_WARN_IF(!dc)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsIPrintSettingsWin> psWin = do_QueryInterface(aPrintSettings);
+  MOZ_ASSERT(psWin);
+  psWin->CopyFromNative(dc, devmode);
+  ::DeleteDC(dc);
+
+  return NS_OK;
+}
diff --git a/widget/windows/nsDeviceContextSpecWin.h b/widget/windows/nsDeviceContextSpecWin.h
new file mode 100644
index 0000000000..fff6472d62
--- /dev/null
+++ b/widget/windows/nsDeviceContextSpecWin.h
@@ -0,0 +1,98 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsDeviceContextSpecWin_h___
+#define nsDeviceContextSpecWin_h___
+
+#include "nsCOMPtr.h"
+#include "nsIDeviceContextSpec.h"
+#include "nsPrinterListBase.h"
+#include "nsIPrintSettings.h"
+#include <windows.h>
+#include "mozilla/Attributes.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/gfx/PrintPromise.h"
+
+class nsIFile;
+class nsIWidget;
+
+class nsDeviceContextSpecWin : public nsIDeviceContextSpec {
+ public:
+  nsDeviceContextSpecWin();
+
+  NS_DECL_ISUPPORTS
+
+  already_AddRefed<PrintTarget> MakePrintTarget() final;
+  NS_IMETHOD BeginDocument(const nsAString& aTitle,
+                           const nsAString& aPrintToFileName,
+                           int32_t aStartPage, int32_t aEndPage) override {
+    return NS_OK;
+  }
+  RefPtr<mozilla::gfx::PrintEndDocumentPromise> EndDocument() override;
+  NS_IMETHOD BeginPage(const IntSize& aSizeInPoints) override { return NS_OK; }
+  NS_IMETHOD EndPage() override { return NS_OK; }
+
+  NS_IMETHOD Init(nsIPrintSettings* aPS, bool aIsPrintPreview) override;
+
+  void GetDriverName(nsAString& aDriverName) const {
+    aDriverName = mDriverName;
+  }
+  void GetDeviceName(nsAString& aDeviceName) const {
+    aDeviceName = mDeviceName;
+  }
+
+  // The GetDevMode will return a pointer to a DevMode
+  // whether it is from the Global memory handle or just the DevMode
+  // To get the DevMode from the Global memory Handle it must lock it
+  // So this call must be paired with a call to UnlockGlobalHandle
+  void GetDevMode(LPDEVMODEW& aDevMode);
+
+  // helper functions
+  nsresult GetDataFromPrinter(const nsAString& aName,
+                              nsIPrintSettings* aPS = nullptr);
+
+ protected:
+  void SetDeviceName(const nsAString& aDeviceName);
+  void SetDriverName(const nsAString& aDriverName);
+  void SetDevMode(LPDEVMODEW aDevMode);
+
+  virtual ~nsDeviceContextSpecWin();
+
+  nsString mDriverName;
+  nsString mDeviceName;
+  LPDEVMODEW mDevMode = nullptr;
+
+  int16_t mOutputFormat = nsIPrintSettings::kOutputFormatNative;
+
+  // A temporary file to create an "anonymous" print target. See bug 1664253,
+  // this should ideally not be needed.
+  nsCOMPtr<nsIFile> mTempFile;
+};
+
+//-------------------------------------------------------------------------
+// Printer List
+//-------------------------------------------------------------------------
+class nsPrinterListWin final : public nsPrinterListBase {
+ public:
+  NS_IMETHOD InitPrintSettingsFromPrinter(const nsAString&,
+                                          nsIPrintSettings*) final;
+
+  nsTArray<PrinterInfo> Printers() const final;
+  RefPtr<nsIPrinter> CreatePrinter(PrinterInfo) const final;
+
+  nsPrinterListWin() = default;
+
+ protected:
+  nsresult SystemDefaultPrinterName(nsAString&) const final;
+
+  mozilla::Maybe<PrinterInfo> PrinterByName(nsString) const final;
+  mozilla::Maybe<PrinterInfo> PrinterBySystemName(
+      nsString aPrinterName) const final;
+
+ private:
+  ~nsPrinterListWin();
+};
+
+#endif
diff --git a/widget/windows/nsDragService.cpp b/widget/windows/nsDragService.cpp
new file mode 100644
index 0000000000..80f545d9a7
--- /dev/null
+++ b/widget/windows/nsDragService.cpp
@@ -0,0 +1,664 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <ole2.h>
+#include <oleidl.h>
+#include <shlobj.h>
+#include <shlwapi.h>
+
+// shellapi.h is needed to build with WIN32_LEAN_AND_MEAN
+#include <shellapi.h>
+
+#include "mozilla/RefPtr.h"
+#include "nsDragService.h"
+#include "nsITransferable.h"
+#include "nsDataObj.h"
+
+#include "nsWidgetsCID.h"
+#include "nsNativeDragTarget.h"
+#include "nsNativeDragSource.h"
+#include "nsClipboard.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/DocumentInlines.h"
+#include "nsDataObjCollection.h"
+
+#include "nsArrayUtils.h"
+#include "nsString.h"
+#include "nsEscape.h"
+#include "nsIScreenManager.h"
+#include "nsToolkit.h"
+#include "nsCRT.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsUnicharUtils.h"
+#include "nsRect.h"
+#include "nsMathUtils.h"
+#include "WinUtils.h"
+#include "KeyboardLayout.h"
+#include "gfxContext.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/DataSurfaceHelpers.h"
+#include "mozilla/gfx/Tools.h"
+#include "mozilla/ScopeExit.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using namespace mozilla::widget;
+
+//-------------------------------------------------------------------------
+//
+// DragService constructor
+//
+//-------------------------------------------------------------------------
+nsDragService::nsDragService()
+    : mDataObject(nullptr), mSentLocalDropEvent(false) {}
+
+//-------------------------------------------------------------------------
+//
+// DragService destructor
+//
+//-------------------------------------------------------------------------
+nsDragService::~nsDragService() { NS_IF_RELEASE(mDataObject); }
+
+bool nsDragService::CreateDragImage(nsINode* aDOMNode,
+                                    const Maybe<CSSIntRegion>& aRegion,
+                                    SHDRAGIMAGE* psdi) {
+  if (!psdi) return false;
+
+  memset(psdi, 0, sizeof(SHDRAGIMAGE));
+  if (!aDOMNode) return false;
+
+  // Prepare the drag image
+  LayoutDeviceIntRect dragRect;
+  RefPtr<SourceSurface> surface;
+  nsPresContext* pc;
+  DrawDrag(aDOMNode, aRegion, mScreenPosition, &dragRect, &surface, &pc);
+  if (!surface) return false;
+
+  uint32_t bmWidth = dragRect.Width(), bmHeight = dragRect.Height();
+
+  if (bmWidth == 0 || bmHeight == 0) return false;
+
+  psdi->crColorKey = CLR_NONE;
+
+  RefPtr<DataSourceSurface> dataSurface = Factory::CreateDataSourceSurface(
+      IntSize(bmWidth, bmHeight), SurfaceFormat::B8G8R8A8);
+  NS_ENSURE_TRUE(dataSurface, false);
+
+  DataSourceSurface::MappedSurface map;
+  if (!dataSurface->Map(DataSourceSurface::MapType::READ_WRITE, &map)) {
+    return false;
+  }
+
+  RefPtr<DrawTarget> dt = Factory::CreateDrawTargetForData(
+      BackendType::CAIRO, map.mData, dataSurface->GetSize(), map.mStride,
+      dataSurface->GetFormat());
+  if (!dt) {
+    dataSurface->Unmap();
+    return false;
+  }
+
+  dt->DrawSurface(
+      surface,
+      Rect(0, 0, dataSurface->GetSize().width, dataSurface->GetSize().height),
+      Rect(0, 0, surface->GetSize().width, surface->GetSize().height),
+      DrawSurfaceOptions(), DrawOptions(1.0f, CompositionOp::OP_SOURCE));
+  dt->Flush();
+
+  BITMAPV5HEADER bmih;
+  memset((void*)&bmih, 0, sizeof(BITMAPV5HEADER));
+  bmih.bV5Size = sizeof(BITMAPV5HEADER);
+  bmih.bV5Width = bmWidth;
+  bmih.bV5Height = -(int32_t)bmHeight;  // flip vertical
+  bmih.bV5Planes = 1;
+  bmih.bV5BitCount = 32;
+  bmih.bV5Compression = BI_BITFIELDS;
+  bmih.bV5RedMask = 0x00FF0000;
+  bmih.bV5GreenMask = 0x0000FF00;
+  bmih.bV5BlueMask = 0x000000FF;
+  bmih.bV5AlphaMask = 0xFF000000;
+
+  HDC hdcSrc = CreateCompatibleDC(nullptr);
+  void* lpBits = nullptr;
+  if (hdcSrc) {
+    psdi->hbmpDragImage =
+        ::CreateDIBSection(hdcSrc, (BITMAPINFO*)&bmih, DIB_RGB_COLORS,
+                           (void**)&lpBits, nullptr, 0);
+    if (psdi->hbmpDragImage && lpBits) {
+      CopySurfaceDataToPackedArray(map.mData, static_cast<uint8_t*>(lpBits),
+                                   dataSurface->GetSize(), map.mStride,
+                                   BytesPerPixel(dataSurface->GetFormat()));
+    }
+
+    psdi->sizeDragImage.cx = bmWidth;
+    psdi->sizeDragImage.cy = bmHeight;
+
+    const auto screenPoint =
+        LayoutDeviceIntPoint::Round(mScreenPosition * pc->CSSToDevPixelScale());
+    psdi->ptOffset.x = screenPoint.x - dragRect.X();
+    psdi->ptOffset.y = screenPoint.y - dragRect.Y();
+
+    DeleteDC(hdcSrc);
+  }
+
+  dataSurface->Unmap();
+
+  return psdi->hbmpDragImage != nullptr;
+}
+
+//-------------------------------------------------------------------------
+nsresult nsDragService::InvokeDragSessionImpl(
+    nsIArray* anArrayTransferables, const Maybe<CSSIntRegion>& aRegion,
+    uint32_t aActionType) {
+  // Try and get source URI of the items that are being dragged
+  nsIURI* uri = nullptr;
+
+  RefPtr<dom::Document> doc(mSourceDocument);
+  if (doc) {
+    uri = doc->GetDocumentURI();
+  }
+
+  uint32_t numItemsToDrag = 0;
+  nsresult rv = anArrayTransferables->GetLength(&numItemsToDrag);
+  if (!numItemsToDrag) return NS_ERROR_FAILURE;
+
+  // The clipboard class contains some static utility methods that we
+  // can use to create an IDataObject from the transferable
+
+  // if we're dragging more than one item, we need to create a
+  // "collection" object to fake out the OS. This collection contains
+  // one |IDataObject| for each transferable. If there is just the one
+  // (most cases), only pass around the native |IDataObject|.
+  RefPtr<IDataObject> itemToDrag;
+  if (numItemsToDrag > 1) {
+    nsDataObjCollection* dataObjCollection = new nsDataObjCollection();
+    if (!dataObjCollection) return NS_ERROR_OUT_OF_MEMORY;
+    itemToDrag = dataObjCollection;
+    for (uint32_t i = 0; i < numItemsToDrag; ++i) {
+      nsCOMPtr<nsITransferable> trans =
+          do_QueryElementAt(anArrayTransferables, i);
+      if (trans) {
+        RefPtr<IDataObject> dataObj;
+        rv = nsClipboard::CreateNativeDataObject(trans, getter_AddRefs(dataObj),
+                                                 uri);
+        NS_ENSURE_SUCCESS(rv, rv);
+        // Add the flavors to the collection object too
+        rv = nsClipboard::SetupNativeDataObject(trans, dataObjCollection);
+        NS_ENSURE_SUCCESS(rv, rv);
+
+        dataObjCollection->AddDataObject(dataObj);
+      }
+    }
+  }  // if dragging multiple items
+  else {
+    nsCOMPtr<nsITransferable> trans =
+        do_QueryElementAt(anArrayTransferables, 0);
+    if (trans) {
+      rv = nsClipboard::CreateNativeDataObject(trans,
+                                               getter_AddRefs(itemToDrag), uri);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }  // else dragging a single object
+
+  // Create a drag image if support is available
+  IDragSourceHelper* pdsh;
+  if (SUCCEEDED(CoCreateInstance(CLSID_DragDropHelper, nullptr,
+                                 CLSCTX_INPROC_SERVER, IID_IDragSourceHelper,
+                                 (void**)&pdsh))) {
+    SHDRAGIMAGE sdi;
+    if (CreateDragImage(mSourceNode, aRegion, &sdi)) {
+      if (FAILED(pdsh->InitializeFromBitmap(&sdi, itemToDrag)))
+        DeleteObject(sdi.hbmpDragImage);
+    }
+    pdsh->Release();
+  }
+
+  // Kick off the native drag session
+  return StartInvokingDragSession(itemToDrag, aActionType);
+}
+
+static HWND GetSourceWindow(dom::Document* aSourceDocument) {
+  if (!aSourceDocument) {
+    return nullptr;
+  }
+
+  auto* pc = aSourceDocument->GetPresContext();
+  if (!pc) {
+    return nullptr;
+  }
+
+  nsCOMPtr<nsIWidget> widget = pc->GetRootWidget();
+  if (!widget) {
+    return nullptr;
+  }
+
+  return (HWND)widget->GetNativeData(NS_NATIVE_WINDOW);
+}
+
+//-------------------------------------------------------------------------
+nsresult nsDragService::StartInvokingDragSession(IDataObject* aDataObj,
+                                                 uint32_t aActionType) {
+  // To do the drag we need to create an object that
+  // implements the IDataObject interface (for OLE)
+  RefPtr<nsNativeDragSource> nativeDragSrc =
+      new nsNativeDragSource(mDataTransfer);
+
+  // Now figure out what the native drag effect should be
+  DWORD winDropRes;
+  DWORD effects = DROPEFFECT_SCROLL;
+  if (aActionType & DRAGDROP_ACTION_COPY) {
+    effects |= DROPEFFECT_COPY;
+  }
+  if (aActionType & DRAGDROP_ACTION_MOVE) {
+    effects |= DROPEFFECT_MOVE;
+  }
+  if (aActionType & DRAGDROP_ACTION_LINK) {
+    effects |= DROPEFFECT_LINK;
+  }
+
+  // XXX not sure why we bother to cache this, it can change during
+  // the drag
+  mDragAction = aActionType;
+  mSentLocalDropEvent = false;
+
+  // Start dragging
+  StartDragSession();
+  OpenDragPopup();
+
+  RefPtr<IDataObjectAsyncCapability> pAsyncOp;
+  // Offer to do an async drag
+  if (SUCCEEDED(aDataObj->QueryInterface(IID_IDataObjectAsyncCapability,
+                                         getter_AddRefs(pAsyncOp)))) {
+    pAsyncOp->SetAsyncMode(VARIANT_TRUE);
+  } else {
+    MOZ_ASSERT_UNREACHABLE("When did our data object stop being async");
+  }
+
+  // Call the native D&D method
+  HRESULT res = ::DoDragDrop(aDataObj, nativeDragSrc, effects, &winDropRes);
+
+  // In  cases where the drop operation completed outside the application,
+  // update the source node's DataTransfer dropEffect value so it is up to date.
+  if (!mSentLocalDropEvent) {
+    uint32_t dropResult;
+    // Order is important, since multiple flags can be returned.
+    if (winDropRes & DROPEFFECT_COPY)
+      dropResult = DRAGDROP_ACTION_COPY;
+    else if (winDropRes & DROPEFFECT_LINK)
+      dropResult = DRAGDROP_ACTION_LINK;
+    else if (winDropRes & DROPEFFECT_MOVE)
+      dropResult = DRAGDROP_ACTION_MOVE;
+    else
+      dropResult = DRAGDROP_ACTION_NONE;
+
+    if (mDataTransfer) {
+      if (res == DRAGDROP_S_DROP)  // Success
+        mDataTransfer->SetDropEffectInt(dropResult);
+      else
+        mDataTransfer->SetDropEffectInt(DRAGDROP_ACTION_NONE);
+    }
+  }
+
+  mUserCancelled = nativeDragSrc->UserCancelled();
+
+  // We're done dragging, get the cursor position and end the drag
+  // Use GetMessagePos to get the position of the mouse at the last message
+  // seen by the event loop. (Bug 489729)
+  // Note that we must convert this from device pixels back to Windows logical
+  // pixels (bug 818927).
+  DWORD pos = ::GetMessagePos();
+  POINT cpos;
+  cpos.x = GET_X_LPARAM(pos);
+  cpos.y = GET_Y_LPARAM(pos);
+  if (auto wnd = GetSourceWindow(mSourceDocument)) {
+    // Convert from screen to client coordinates like nsWindow::InitEvent does.
+    ::ScreenToClient(wnd, &cpos);
+  }
+  SetDragEndPoint(LayoutDeviceIntPoint(cpos.x, cpos.y));
+
+  ModifierKeyState modifierKeyState;
+  EndDragSession(true, modifierKeyState.GetModifiers());
+
+  mDoingDrag = false;
+
+  return DRAGDROP_S_DROP == res ? NS_OK : NS_ERROR_FAILURE;
+}
+
+//-------------------------------------------------------------------------
+// Make Sure we have the right kind of object
+nsDataObjCollection* nsDragService::GetDataObjCollection(
+    IDataObject* aDataObj) {
+  nsDataObjCollection* dataObjCol = nullptr;
+  if (aDataObj) {
+    nsIDataObjCollection* dataObj;
+    if (aDataObj->QueryInterface(IID_IDataObjCollection, (void**)&dataObj) ==
+        S_OK) {
+      dataObjCol = static_cast<nsDataObjCollection*>(aDataObj);
+      dataObj->Release();
+    }
+  }
+
+  return dataObjCol;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsDragService::GetNumDropItems(uint32_t* aNumItems) {
+  if (!mDataObject) {
+    *aNumItems = 0;
+    return NS_OK;
+  }
+
+  if (IsCollectionObject(mDataObject)) {
+    nsDataObjCollection* dataObjCol = GetDataObjCollection(mDataObject);
+    // If the count cannot be determined just return 0.
+    // This can happen if we have collection data of type
+    // MULTI_MIME ("Mozilla/IDataObjectCollectionFormat") on the clipboard
+    // from another process but we can't obtain an IID_IDataObjCollection
+    // from this process.
+    *aNumItems = dataObjCol ? dataObjCol->GetNumDataObjects() : 0;
+    return NS_OK;
+  }
+  // Next check if we have a file drop. Return the number of files in
+  // the file drop as the number of items we have, pretending like we
+  // actually have > 1 drag item.
+  FORMATETC fe2;
+  SET_FORMATETC(fe2, CF_HDROP, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+  if (SUCCEEDED(mDataObject->QueryGetData(&fe2))) {
+    STGMEDIUM stm;
+    if (FAILED(mDataObject->GetData(&fe2, &stm))) {
+      *aNumItems = 1;
+      return NS_OK;
+    }
+    HDROP hdrop = static_cast<HDROP>(GlobalLock(stm.hGlobal));
+    MOZ_ASSERT(hdrop != NULL);
+    *aNumItems = ::DragQueryFileW(hdrop, 0xFFFFFFFF, nullptr, 0);
+    ::GlobalUnlock(stm.hGlobal);
+    ::ReleaseStgMedium(&stm);
+    // Data may be provided later, so assume we have 1 item
+    if (*aNumItems == 0) {
+      *aNumItems = 1;
+    }
+    return NS_OK;
+  }
+  // Next check if we have a virtual file drop.
+  SET_FORMATETC(fe2, nsClipboard::GetClipboardFileDescriptorFormatW(), 0,
+                DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+  STGMEDIUM stm;
+
+  if (SUCCEEDED(mDataObject->GetData(&fe2, &stm))) {
+    LPFILEGROUPDESCRIPTOR pDesc =
+        static_cast<LPFILEGROUPDESCRIPTOR>(GlobalLock(stm.hGlobal));
+    if (pDesc) {
+      *aNumItems = pDesc->cItems;
+    }
+    GlobalUnlock(stm.hGlobal);
+    ReleaseStgMedium(&stm);
+    return NS_OK;
+  }
+  *aNumItems = 1;
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsDragService::GetData(nsITransferable* aTransferable, uint32_t anItem) {
+  // This typcially happens on a drop, the target would be asking
+  // for it's transferable to be filled in
+  // Use a static clipboard utility method for this
+  if (!mDataObject) return NS_ERROR_FAILURE;
+
+  nsresult dataFound = NS_ERROR_FAILURE;
+
+  if (IsCollectionObject(mDataObject)) {
+    // multiple items, use |anItem| as an index into our collection
+    nsDataObjCollection* dataObjCol = GetDataObjCollection(mDataObject);
+    uint32_t cnt = dataObjCol->GetNumDataObjects();
+    if (anItem < cnt) {
+      IDataObject* dataObj = dataObjCol->GetDataObjectAt(anItem);
+      dataFound = nsClipboard::GetDataFromDataObject(dataObj, 0, nullptr,
+                                                     aTransferable);
+    } else
+      NS_WARNING("Index out of range!");
+  } else {
+    // If they are asking for item "0", we can just get it...
+    if (anItem == 0) {
+      dataFound = nsClipboard::GetDataFromDataObject(mDataObject, anItem,
+                                                     nullptr, aTransferable);
+    } else {
+      // It better be a file drop, or else non-zero indexes are invalid!
+      FORMATETC fe2;
+      FORMATETC fe3;
+      SET_FORMATETC(fe2, CF_HDROP, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+      SET_FORMATETC(fe3, nsClipboard::GetClipboardFileDescriptorFormatW(), 0,
+                    DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+      if (SUCCEEDED(mDataObject->QueryGetData(&fe2)) ||
+          SUCCEEDED(mDataObject->QueryGetData(&fe3)))
+        dataFound = nsClipboard::GetDataFromDataObject(mDataObject, anItem,
+                                                       nullptr, aTransferable);
+      else
+        NS_WARNING(
+            "Reqesting non-zero index, but clipboard data is not a "
+            "collection!");
+    }
+  }
+  return dataFound;
+}
+
+//---------------------------------------------------------
+NS_IMETHODIMP
+nsDragService::SetIDataObject(IDataObject* aDataObj) {
+  // When the native drag starts the DragService gets
+  // the IDataObject that is being dragged
+  NS_IF_RELEASE(mDataObject);
+  mDataObject = aDataObj;
+  NS_IF_ADDREF(mDataObject);
+
+  if (MOZ_DRAGSERVICE_LOG_ENABLED()) {
+    MOZ_DRAGSERVICE_LOG("nsDragService::SetIDataObject (%p)", mDataObject);
+    IEnumFORMATETC* pEnum = nullptr;
+    if (mDataObject &&
+        S_OK == mDataObject->EnumFormatEtc(DATADIR_GET, &pEnum)) {
+      MOZ_DRAGSERVICE_LOG("    formats in DataObject:");
+
+      FORMATETC fEtc;
+      while (S_OK == pEnum->Next(1, &fEtc, nullptr)) {
+        nsAutoString format;
+        WinUtils::GetClipboardFormatAsString(fEtc.cfFormat, format);
+        MOZ_DRAGSERVICE_LOG("        FORMAT %s",
+                            NS_ConvertUTF16toUTF8(format).get());
+      }
+      pEnum->Release();
+    }
+  }
+
+  return NS_OK;
+}
+
+//---------------------------------------------------------
+void nsDragService::SetDroppedLocal() {
+  // Sent from the native drag handler, letting us know
+  // a drop occurred within the application vs. outside of it.
+  mSentLocalDropEvent = true;
+  return;
+}
+
+//-------------------------------------------------------------------------
+NS_IMETHODIMP
+nsDragService::IsDataFlavorSupported(const char* aDataFlavor, bool* _retval) {
+  if (!aDataFlavor || !mDataObject || !_retval) {
+    MOZ_DRAGSERVICE_LOG("%s: error", __PRETTY_FUNCTION__);
+    return NS_ERROR_FAILURE;
+  }
+
+  *_retval = false;
+  auto logging = MakeScopeExit([&] {
+    MOZ_DRAGSERVICE_LOG("IsDataFlavorSupported: %s is%s found", aDataFlavor,
+                        *_retval ? "" : " not");
+  });
+
+  FORMATETC fe;
+  UINT format = 0;
+
+  if (IsCollectionObject(mDataObject)) {
+    // We know we have one of our special collection objects.
+    format = nsClipboard::GetFormat(aDataFlavor);
+    SET_FORMATETC(fe, format, 0, DVASPECT_CONTENT, -1,
+                  TYMED_HGLOBAL | TYMED_FILE | TYMED_GDI);
+
+    // See if any one of the IDataObjects in the collection supports
+    // this data type
+    nsDataObjCollection* dataObjCol = GetDataObjCollection(mDataObject);
+    if (dataObjCol) {
+      uint32_t cnt = dataObjCol->GetNumDataObjects();
+      for (uint32_t i = 0; i < cnt; ++i) {
+        IDataObject* dataObj = dataObjCol->GetDataObjectAt(i);
+        if (S_OK == dataObj->QueryGetData(&fe)) {
+          *_retval = true;  // found it!
+        }
+      }
+    }
+    return NS_OK;
+  }
+
+  // Ok, so we have a single object. Check to see if has the correct
+  // data type. Since this can come from an outside app, we also
+  // need to see if we need to perform text->unicode conversion if
+  // the client asked for unicode and it wasn't available.
+  format = nsClipboard::GetFormat(aDataFlavor);
+  SET_FORMATETC(fe, format, 0, DVASPECT_CONTENT, -1,
+                TYMED_HGLOBAL | TYMED_FILE | TYMED_GDI);
+  if (mDataObject->QueryGetData(&fe) == S_OK) {
+    *_retval = true;  // found it!
+    return NS_OK;
+  }
+
+  // We haven't found the exact flavor the client asked for, but
+  // maybe we can still find it from something else that's in the
+  // data object.
+  if (strcmp(aDataFlavor, kTextMime) == 0) {
+    // If unicode wasn't there, it might exist as CF_TEXT, client asked
+    // for unicode and it wasn't present, check if we
+    // have CF_TEXT.  We'll handle the actual data substitution in
+    // the data object.
+    SET_FORMATETC(fe, CF_TEXT, 0, DVASPECT_CONTENT, -1,
+                  TYMED_HGLOBAL | TYMED_FILE | TYMED_GDI);
+    if (mDataObject->QueryGetData(&fe) == S_OK) {
+      *_retval = true;  // found it!
+    }
+    return NS_OK;
+  }
+
+  if (strcmp(aDataFlavor, kURLMime) == 0) {
+    // client asked for a url and it wasn't present, but if we
+    // have a file, then we have a URL to give them (the path, or
+    // the internal URL if an InternetShortcut).
+    format = nsClipboard::GetFormat(kFileMime);
+    SET_FORMATETC(fe, format, 0, DVASPECT_CONTENT, -1,
+                  TYMED_HGLOBAL | TYMED_FILE | TYMED_GDI);
+    if (mDataObject->QueryGetData(&fe) == S_OK) {
+      *_retval = true;  // found it!
+    }
+    return NS_OK;
+  }
+
+  if (format == CF_HDROP) {
+    // Dragging a link from browsers creates both a URL and a FILE which is a
+    // *.url shortcut in the data object. The file is useful when dropping in
+    // Windows Explorer to create a internet shortcut. But when dropping in the
+    // browser, users do not expect to have this file. So do not try to look up
+    // virtal file if there is a URL in the data object.
+    format = nsClipboard::GetFormat(kURLMime);
+    SET_FORMATETC(fe, format, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+    if (mDataObject->QueryGetData(&fe) == S_OK) {
+      return NS_OK;
+    }
+
+    // If the client wants a file, maybe we find a virtual file.
+    format = nsClipboard::GetClipboardFileDescriptorFormatW();
+    SET_FORMATETC(fe, format, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+    if (mDataObject->QueryGetData(&fe) == S_OK) {
+      *_retval = true;  // found it!
+    }
+
+    // XXX should we fall back to CFSTR_FILEDESCRIPTORA?
+    return NS_OK;
+  }
+
+  return NS_OK;
+}
+
+//
+// IsCollectionObject
+//
+// Determine if this is a single |IDataObject| or one of our private
+// collection objects. We know the difference because our collection
+// object will respond to supporting the private |MULTI_MIME| format.
+//
+bool nsDragService::IsCollectionObject(IDataObject* inDataObj) {
+  bool isCollection = false;
+
+  // setup the format object to ask for the MULTI_MIME format. We only
+  // need to do this once
+  static UINT sFormat = 0;
+  static FORMATETC sFE;
+  if (!sFormat) {
+    sFormat = nsClipboard::GetFormat(MULTI_MIME);
+    SET_FORMATETC(sFE, sFormat, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+  }
+
+  // ask the object if it supports it. If yes, we have a collection
+  // object
+  if (inDataObj->QueryGetData(&sFE) == S_OK) isCollection = true;
+
+  return isCollection;
+
+}  // IsCollectionObject
+
+//
+// EndDragSession
+//
+// Override the default to make sure that we release the data object
+// when the drag ends. It seems that OLE doesn't like to let apps quit
+// w/out crashing when we're still holding onto their data
+//
+NS_IMETHODIMP
+nsDragService::EndDragSession(bool aDoneDrag, uint32_t aKeyModifiers) {
+  // Bug 100180: If we've got mouse events captured, make sure we release it -
+  // that way, if we happen to call EndDragSession before diving into a nested
+  // event loop, we can still respond to mouse events.
+  if (::GetCapture()) {
+    ::ReleaseCapture();
+  }
+
+  nsBaseDragService::EndDragSession(aDoneDrag, aKeyModifiers);
+  NS_IF_RELEASE(mDataObject);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsDragService::UpdateDragImage(nsINode* aImage, int32_t aImageX,
+                               int32_t aImageY) {
+  if (!mDataObject) {
+    return NS_OK;
+  }
+
+  nsBaseDragService::UpdateDragImage(aImage, aImageX, aImageY);
+
+  IDragSourceHelper* pdsh;
+  if (SUCCEEDED(CoCreateInstance(CLSID_DragDropHelper, nullptr,
+                                 CLSCTX_INPROC_SERVER, IID_IDragSourceHelper,
+                                 (void**)&pdsh))) {
+    SHDRAGIMAGE sdi;
+    if (CreateDragImage(mSourceNode, Nothing(), &sdi)) {
+      nsNativeDragTarget::DragImageChanged();
+      if (FAILED(pdsh->InitializeFromBitmap(&sdi, mDataObject)))
+        DeleteObject(sdi.hbmpDragImage);
+    }
+    pdsh->Release();
+  }
+
+  return NS_OK;
+}
diff --git a/widget/windows/nsDragService.h b/widget/windows/nsDragService.h
new file mode 100644
index 0000000000..5a86a74f76
--- /dev/null
+++ b/widget/windows/nsDragService.h
@@ -0,0 +1,67 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsDragService_h__
+#define nsDragService_h__
+
+#include "nsBaseDragService.h"
+#include <windows.h>
+#include <shlobj.h>
+
+struct IDataObject;
+class nsDataObjCollection;
+
+/**
+ * Native Win32 DragService wrapper
+ */
+
+class nsDragService : public nsBaseDragService {
+ public:
+  nsDragService();
+  virtual ~nsDragService();
+
+  // nsBaseDragService
+  MOZ_CAN_RUN_SCRIPT virtual nsresult InvokeDragSessionImpl(
+      nsIArray* anArrayTransferables,
+      const mozilla::Maybe<mozilla::CSSIntRegion>& aRegion,
+      uint32_t aActionType);
+
+  // nsIDragSession
+  NS_IMETHOD GetData(nsITransferable* aTransferable, uint32_t anItem) override;
+  NS_IMETHOD GetNumDropItems(uint32_t* aNumItems) override;
+  NS_IMETHOD IsDataFlavorSupported(const char* aDataFlavor,
+                                   bool* _retval) override;
+  MOZ_CAN_RUN_SCRIPT NS_IMETHOD EndDragSession(bool aDoneDrag,
+                                               uint32_t aKeyModifiers) override;
+  NS_IMETHOD UpdateDragImage(nsINode* aImage, int32_t aImageX,
+                             int32_t aImageY) override;
+
+  // native impl.
+  NS_IMETHOD SetIDataObject(IDataObject* aDataObj);
+  MOZ_CAN_RUN_SCRIPT nsresult StartInvokingDragSession(IDataObject* aDataObj,
+                                                       uint32_t aActionType);
+
+  // A drop occurred within the application vs. outside of it.
+  void SetDroppedLocal();
+
+  IDataObject* GetDataObject() { return mDataObject; }
+
+ protected:
+  nsDataObjCollection* GetDataObjCollection(IDataObject* aDataObj);
+
+  // determine if we have a single data object or one of our private
+  // collections
+  bool IsCollectionObject(IDataObject* inDataObj);
+
+  // Create a bitmap for drag operations
+  bool CreateDragImage(nsINode* aDOMNode,
+                       const mozilla::Maybe<mozilla::CSSIntRegion>& aRegion,
+                       SHDRAGIMAGE* psdi);
+
+  IDataObject* mDataObject;
+  bool mSentLocalDropEvent;
+};
+
+#endif  // nsDragService_h__
diff --git a/widget/windows/nsFilePicker.cpp b/widget/windows/nsFilePicker.cpp
new file mode 100644
index 0000000000..310c54bb40
--- /dev/null
+++ b/widget/windows/nsFilePicker.cpp
@@ -0,0 +1,1078 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsFilePicker.h"
+
+#include <cderr.h>
+#include <shlobj.h>
+#include <shlwapi.h>
+#include <sysinfoapi.h>
+#include <winerror.h>
+#include <winuser.h>
+#include <utility>
+
+#include "ContentAnalysis.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/BackgroundHangMonitor.h"
+#include "mozilla/Components.h"
+#include "mozilla/dom/BrowsingContext.h"
+#include "mozilla/dom/Directory.h"
+#include "mozilla/Logging.h"
+#include "mozilla/ipc/UtilityProcessManager.h"
+#include "mozilla/ProfilerLabels.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/WindowsVersion.h"
+#include "nsCRT.h"
+#include "nsEnumeratorUtils.h"
+#include "nsIContentAnalysis.h"
+#include "nsNetUtil.h"
+#include "nsPIDOMWindow.h"
+#include "nsPrintfCString.h"
+#include "nsReadableUtils.h"
+#include "nsString.h"
+#include "nsToolkit.h"
+#include "nsWindow.h"
+#include "WinUtils.h"
+
+#include "mozilla/glean/GleanMetrics.h"
+
+#include "mozilla/widget/filedialog/WinFileDialogCommands.h"
+#include "mozilla/widget/filedialog/WinFileDialogParent.h"
+
+using mozilla::UniquePtr;
+
+using namespace mozilla::widget;
+
+UniquePtr<char16_t[], nsFilePicker::FreeDeleter>
+    nsFilePicker::sLastUsedUnicodeDirectory;
+
+using mozilla::LogLevel;
+
+#define MAX_EXTENSION_LENGTH 10
+
+///////////////////////////////////////////////////////////////////////////////
+// Helper classes
+
+// Manages matching PickerOpen/PickerClosed calls on the parent widget.
+class AutoWidgetPickerState {
+  static RefPtr<nsWindow> GetWindowForWidget(nsIWidget* aWidget) {
+    MOZ_ASSERT(NS_IsMainThread());
+    if (!aWidget) {
+      return nullptr;
+    }
+    HWND hwnd = (HWND)aWidget->GetNativeData(NS_NATIVE_WINDOW);
+    return RefPtr(WinUtils::GetNSWindowPtr(hwnd));
+  }
+
+ public:
+  explicit AutoWidgetPickerState(nsIWidget* aWidget)
+      : mWindow(GetWindowForWidget(aWidget)) {
+    MOZ_ASSERT(mWindow);
+    if (mWindow) mWindow->PickerOpen();
+  }
+  ~AutoWidgetPickerState() {
+    // may be null if moved-from
+    if (mWindow) mWindow->PickerClosed();
+  }
+
+  AutoWidgetPickerState(AutoWidgetPickerState const&) = delete;
+  AutoWidgetPickerState(AutoWidgetPickerState&& that) noexcept = default;
+
+ private:
+  RefPtr<nsWindow> mWindow;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+// nsIFilePicker
+
+nsFilePicker::nsFilePicker() : mSelectedType(1) {}
+
+NS_IMPL_ISUPPORTS(nsFilePicker, nsIFilePicker)
+
+NS_IMETHODIMP nsFilePicker::Init(
+    mozIDOMWindowProxy* aParent, const nsAString& aTitle,
+    nsIFilePicker::Mode aMode,
+    mozilla::dom::BrowsingContext* aBrowsingContext) {
+  // Don't attempt to open a real file-picker in headless mode.
+  if (gfxPlatform::IsHeadless()) {
+    return nsresult::NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsCOMPtr<nsPIDOMWindowOuter> window = do_QueryInterface(aParent);
+  nsIDocShell* docShell = window ? window->GetDocShell() : nullptr;
+  mLoadContext = do_QueryInterface(docShell);
+
+  return nsBaseFilePicker::Init(aParent, aTitle, aMode, aBrowsingContext);
+}
+
+namespace mozilla::detail {
+// Boilerplate for remotely showing a file dialog.
+template <typename ActionType,
+          typename ReturnType = typename decltype(std::declval<ActionType>()(
+              nullptr))::element_type::ResolveValueType>
+static auto ShowRemote(ActionType&& action)
+    -> RefPtr<MozPromise<ReturnType, HRESULT, true>> {
+  using RetPromise = MozPromise<ReturnType, HRESULT, true>;
+
+  constexpr static const auto fail = []() {
+    return RetPromise::CreateAndReject(E_FAIL, __PRETTY_FUNCTION__);
+  };
+
+  auto mgr = mozilla::ipc::UtilityProcessManager::GetSingleton();
+  if (!mgr) {
+    MOZ_ASSERT(false);
+    return fail();
+  }
+
+  auto wfda = mgr->CreateWinFileDialogActor();
+  if (!wfda) {
+    return fail();
+  }
+
+  using mozilla::widget::filedialog::sLogFileDialog;
+
+  return wfda->Then(
+      mozilla::GetMainThreadSerialEventTarget(),
+      "nsFilePicker ShowRemote acquire",
+      [action = std::forward<ActionType>(action)](
+          filedialog::ProcessProxy const& p) -> RefPtr<RetPromise> {
+        MOZ_LOG(sLogFileDialog, LogLevel::Info,
+                ("nsFilePicker ShowRemote first callback: p = [%p]", p.get()));
+
+        // false positive: not actually redundant
+        // NOLINTNEXTLINE(readability-redundant-smartptr-get)
+        return action(p.get())->Then(
+            mozilla::GetMainThreadSerialEventTarget(),
+            "nsFilePicker ShowRemote call",
+            [p](ReturnType ret) {
+              return RetPromise::CreateAndResolve(std::move(ret),
+                                                  __PRETTY_FUNCTION__);
+            },
+            [](mozilla::ipc::ResponseRejectReason error) {
+              MOZ_LOG(sLogFileDialog, LogLevel::Error,
+                      ("IPC call rejected: %zu", size_t(error)));
+              return fail();
+            });
+      },
+      [](nsresult error) -> RefPtr<RetPromise> {
+        MOZ_LOG(sLogFileDialog, LogLevel::Error,
+                ("could not acquire WinFileDialog: %zu", size_t(error)));
+        return fail();
+      });
+}
+
+// fd_async
+//
+// Wrapper-namespace for the AsyncExecute() and AsyncAll() functions.
+namespace fd_async {
+
+// Implementation details of, specifically, the AsyncExecute() and AsyncAll()
+// functions.
+namespace details {
+// Helper for generically copying ordinary types and nsTArray (which lacks a
+// copy constructor) in the same breath.
+template <typename T>
+static T Copy(T const& val) {
+  return val;
+}
+template <typename T>
+static nsTArray<T> Copy(nsTArray<T> const& arr) {
+  return arr.Clone();
+}
+
+// The possible execution strategies of AsyncExecute.
+enum Strategy { Local, Remote, RemoteWithFallback };
+
+// Decode the relevant preference to determine the desired execution-
+// strategy.
+static Strategy GetStrategy() {
+  int32_t const pref =
+      mozilla::StaticPrefs::widget_windows_utility_process_file_picker();
+  switch (pref) {
+    case -1:
+      return Local;
+    case 2:
+      return Remote;
+    case 1:
+      return RemoteWithFallback;
+
+    default:
+#ifdef NIGHTLY_BUILD
+      // on Nightly builds, fall back to local on failure
+      return RemoteWithFallback;
+#else
+      // on release and beta, remain local-only for now
+      return Local;
+#endif
+  }
+};
+
+template <typename T>
+class AsyncAllIterator final {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(AsyncAllIterator)
+  AsyncAllIterator(
+      nsTArray<T> aItems,
+      std::function<
+          RefPtr<mozilla::MozPromise<bool, nsresult, true>>(const T& item)>
+          aPredicate,
+      RefPtr<mozilla::MozPromise<bool, nsresult, true>::Private> aPromise)
+      : mItems(std::move(aItems)),
+        mNextIndex(0),
+        mPredicate(std::move(aPredicate)),
+        mPromise(std::move(aPromise)) {}
+
+  void StartIterating() { ContinueIterating(); }
+
+ private:
+  ~AsyncAllIterator() = default;
+  void ContinueIterating() {
+    if (mNextIndex >= mItems.Length()) {
+      mPromise->Resolve(true, __func__);
+      return;
+    }
+    mPredicate(mItems.ElementAt(mNextIndex))
+        ->Then(
+            mozilla::GetMainThreadSerialEventTarget(), __func__,
+            [self = RefPtr{this}](bool aResult) {
+              if (!aResult) {
+                self->mPromise->Resolve(false, __func__);
+                return;
+              }
+              ++self->mNextIndex;
+              self->ContinueIterating();
+            },
+            [self = RefPtr{this}](nsresult aError) {
+              self->mPromise->Reject(aError, __func__);
+            });
+  }
+  nsTArray<T> mItems;
+  uint32_t mNextIndex;
+  std::function<RefPtr<mozilla::MozPromise<bool, nsresult, true>>(
+      const T& item)>
+      mPredicate;
+  RefPtr<mozilla::MozPromise<bool, nsresult, true>::Private> mPromise;
+};
+
+namespace telemetry {
+static uint32_t Delta(uint64_t tb, uint64_t ta) {
+  // FILETIMEs are 100ns intervals; we reduce that to 1ms.
+  // (`u32::max()` milliseconds is roughly 47.91 days.)
+  return uint32_t((tb - ta) / 10'000);
+};
+static nsCString HexString(HRESULT val) {
+  return nsPrintfCString("%08lX", val);
+};
+
+static void RecordSuccess(uint64_t (&&time)[2]) {
+  auto [t0, t1] = time;
+
+  namespace glean_fd = mozilla::glean::file_dialog;
+  glean_fd::FallbackExtra extra{
+      .hresultLocal = Nothing(),
+      .hresultRemote = Nothing(),
+      .succeeded = Some(true),
+      .timeLocal = Nothing(),
+      .timeRemote = Some(Delta(t1, t0)),
+  };
+  glean_fd::fallback.Record(Some(extra));
+}
+
+static void RecordFailure(uint64_t (&&time)[3], HRESULT hrRemote,
+                          HRESULT hrLocal) {
+  auto [t0, t1, t2] = time;
+
+  {
+    namespace glean_fd = mozilla::glean::file_dialog;
+    glean_fd::FallbackExtra extra{
+        .hresultLocal = Some(HexString(hrLocal)),
+        .hresultRemote = Some(HexString(hrRemote)),
+        .succeeded = Some(false),
+        .timeLocal = Some(Delta(t2, t1)),
+        .timeRemote = Some(Delta(t1, t0)),
+    };
+    glean_fd::fallback.Record(Some(extra));
+  }
+}
+
+}  // namespace telemetry
+}  // namespace details
+
+// Invoke either or both of a "do locally" and "do remotely" function with the
+// provided arguments, depending on the relevant preference-value and whether
+// or not the remote version fails.
+//
+// Both functions must be asynchronous, returning a `RefPtr<MozPromise<...>>`.
+// "Failure" is defined as the promise being rejected.
+template <typename Fn1, typename Fn2, typename... Args>
+static auto AsyncExecute(Fn1 local, Fn2 remote, Args const&... args)
+    -> std::invoke_result_t<Fn1, Args...> {
+  using namespace details;
+
+  static_assert(std::is_same_v<std::invoke_result_t<Fn1, Args...>,
+                               std::invoke_result_t<Fn2, Args...>>);
+  using PromiseT = typename std::invoke_result_t<Fn1, Args...>::element_type;
+
+  constexpr static char kFunctionName[] = "LocalAndOrRemote::AsyncExecute";
+
+  switch (GetStrategy()) {
+    case Local:
+      return local(args...);
+
+    case Remote:
+      return remote(args...);
+
+    case RemoteWithFallback:
+      // more complicated; continue below
+      break;
+  }
+
+  // capture time for telemetry
+  constexpr static const auto GetTime = []() -> uint64_t {
+    FILETIME t;
+    ::GetSystemTimeAsFileTime(&t);
+    return (uint64_t(t.dwHighDateTime) << 32) | t.dwLowDateTime;
+  };
+  uint64_t const t0 = GetTime();
+
+  return remote(args...)->Then(
+      NS_GetCurrentThread(), kFunctionName,
+      [t0](typename PromiseT::ResolveValueType result) -> RefPtr<PromiseT> {
+        // success; stop here
+        auto const t1 = GetTime();
+        // record success
+        telemetry::RecordSuccess({t0, t1});
+        return PromiseT::CreateAndResolve(result, kFunctionName);
+      },
+      // initialized lambda pack captures are C++20 (clang 9, gcc 9);
+      // `make_tuple` is just a C++17 workaround
+      [=, tuple = std::make_tuple(Copy(args)...)](
+          typename PromiseT::RejectValueType err) mutable -> RefPtr<PromiseT> {
+        // failure; record time
+        auto const t1 = GetTime();
+        HRESULT const hrRemote = err;
+
+        // retry locally...
+        auto p0 = std::apply(local, std::move(tuple));
+        // ...then record the telemetry event
+        return p0->Then(
+            NS_GetCurrentThread(), kFunctionName,
+            [t0, t1,
+             hrRemote](typename PromiseT::ResolveOrRejectValue const& val)
+                -> RefPtr<PromiseT> {
+              auto const t2 = GetTime();
+              HRESULT const hrLocal = val.IsReject() ? val.RejectValue() : S_OK;
+              telemetry::RecordFailure({t0, t1, t2}, hrRemote, hrLocal);
+
+              return PromiseT::CreateAndResolveOrReject(val, kFunctionName);
+            });
+      });
+}
+
+// Asynchronously invokes `aPredicate` on each member of `aItems`.
+// Yields `false` (and stops immediately) if any invocation of
+// `predicate` yielded `false`; otherwise yields `true`.
+template <typename T>
+static RefPtr<mozilla::MozPromise<bool, nsresult, true>> AsyncAll(
+    nsTArray<T> aItems,
+    std::function<
+        RefPtr<mozilla::MozPromise<bool, nsresult, true>>(const T& item)>
+        aPredicate) {
+  auto promise =
+      mozilla::MakeRefPtr<mozilla::MozPromise<bool, nsresult, true>::Private>(
+          __func__);
+  auto iterator = mozilla::MakeRefPtr<details::AsyncAllIterator<T>>(
+      std::move(aItems), aPredicate, promise);
+  iterator->StartIterating();
+  return promise;
+}
+}  // namespace fd_async
+
+using fd_async::AsyncAll;
+using fd_async::AsyncExecute;
+
+}  // namespace mozilla::detail
+
+/* static */
+nsFilePicker::FPPromise<filedialog::Results> nsFilePicker::ShowFilePickerRemote(
+    HWND parent, filedialog::FileDialogType type,
+    nsTArray<filedialog::Command> const& commands) {
+  using mozilla::widget::filedialog::sLogFileDialog;
+  return mozilla::detail::ShowRemote(
+      [parent, type,
+       commands = commands.Clone()](filedialog::WinFileDialogParent* p) {
+        MOZ_LOG(sLogFileDialog, LogLevel::Info,
+                ("%s: p = [%p]", __PRETTY_FUNCTION__, p));
+        return p->SendShowFileDialog((uintptr_t)parent, type, commands);
+      });
+}
+
+/* static */
+nsFilePicker::FPPromise<nsString> nsFilePicker::ShowFolderPickerRemote(
+    HWND parent, nsTArray<filedialog::Command> const& commands) {
+  using mozilla::widget::filedialog::sLogFileDialog;
+  return mozilla::detail::ShowRemote([parent, commands = commands.Clone()](
+                                         filedialog::WinFileDialogParent* p) {
+    MOZ_LOG(sLogFileDialog, LogLevel::Info,
+            ("%s: p = [%p]", __PRETTY_FUNCTION__, p));
+    return p->SendShowFolderDialog((uintptr_t)parent, commands);
+  });
+}
+
+/* static */
+nsFilePicker::FPPromise<filedialog::Results> nsFilePicker::ShowFilePickerLocal(
+    HWND parent, filedialog::FileDialogType type,
+    nsTArray<filedialog::Command> const& commands) {
+  return filedialog::SpawnFilePicker(parent, type, commands.Clone());
+}
+
+/* static */
+nsFilePicker::FPPromise<nsString> nsFilePicker::ShowFolderPickerLocal(
+    HWND parent, nsTArray<filedialog::Command> const& commands) {
+  return filedialog::SpawnFolderPicker(parent, commands.Clone());
+}
+
+/*
+ * Folder picker invocation
+ */
+
+/*
+ * Show a folder picker.
+ *
+ * @param aInitialDir   The initial directory. The last-used directory will be
+ *                      used if left blank.
+ * @return  A promise which:
+ *          - resolves to true if a file was selected successfully (in which
+ *            case mUnicodeFile will be updated);
+ *          - resolves to false if the dialog was cancelled by the user;
+ *          - is rejected with the associated HRESULT if some error occurred.
+ */
+RefPtr<mozilla::MozPromise<bool, HRESULT, true>> nsFilePicker::ShowFolderPicker(
+    const nsString& aInitialDir) {
+  using Promise = mozilla::MozPromise<bool, HRESULT, true>;
+  constexpr static auto Ok = [](bool val) {
+    return Promise::CreateAndResolve(val, "nsFilePicker::ShowFolderPicker");
+  };
+  constexpr static auto NotOk = [](HRESULT val = E_FAIL) {
+    return Promise::CreateAndReject(val, "nsFilePicker::ShowFolderPicker");
+  };
+
+  namespace fd = ::mozilla::widget::filedialog;
+  nsTArray<fd::Command> commands = {
+      fd::SetOptions(FOS_PICKFOLDERS),
+      fd::SetTitle(mTitle),
+  };
+
+  if (!mOkButtonLabel.IsEmpty()) {
+    commands.AppendElement(fd::SetOkButtonLabel(mOkButtonLabel));
+  }
+
+  if (!aInitialDir.IsEmpty()) {
+    commands.AppendElement(fd::SetFolder(aInitialDir));
+  }
+
+  ScopedRtlShimWindow shim(mParentWidget.get());
+  AutoWidgetPickerState awps(mParentWidget);
+
+  return mozilla::detail::AsyncExecute(&ShowFolderPickerLocal,
+                                       &ShowFolderPickerRemote, shim.get(),
+                                       commands)
+      ->Then(
+          NS_GetCurrentThread(), __PRETTY_FUNCTION__,
+          [self = RefPtr(this), shim = std::move(shim),
+           awps = std::move(awps)](Maybe<nsString> val) {
+            if (val) {
+              self->mUnicodeFile = val.extract();
+              return Ok(true);
+            }
+            return Ok(false);
+          },
+          [](HRESULT err) {
+            NS_WARNING("ShowFolderPicker failed");
+            return NotOk(err);
+          });
+}
+
+/*
+ * File open and save picker invocation
+ */
+
+/*
+ * Show a file picker.
+ *
+ * @param aInitialDir   The initial directory. The last-used directory will be
+ *                      used if left blank.
+ * @return  A promise which:
+ *          - resolves to true if one or more files were selected successfully
+ *            (in which case mUnicodeFile and/or mFiles will be updated);
+ *          - resolves to false if the dialog was cancelled by the user;
+ *          - is rejected with the associated HRESULT if some error occurred.
+ */
+RefPtr<mozilla::MozPromise<bool, HRESULT, true>> nsFilePicker::ShowFilePicker(
+    const nsString& aInitialDir) {
+  AUTO_PROFILER_LABEL("nsFilePicker::ShowFilePicker", OTHER);
+
+  using Promise = mozilla::MozPromise<bool, HRESULT, true>;
+  constexpr static auto Ok = [](bool val) {
+    return Promise::CreateAndResolve(val, "nsFilePicker::ShowFilePicker");
+  };
+  constexpr static auto NotOk = [](HRESULT val = E_FAIL) {
+    return Promise::CreateAndReject(val, "nsFilePicker::ShowFilePicker");
+  };
+
+  namespace fd = ::mozilla::widget::filedialog;
+  nsTArray<fd::Command> commands;
+  // options
+  {
+    FILEOPENDIALOGOPTIONS fos = 0;
+    fos |= FOS_SHAREAWARE | FOS_OVERWRITEPROMPT | FOS_FORCEFILESYSTEM;
+
+    // Handle add to recent docs settings
+    if (IsPrivacyModeEnabled() || !mAddToRecentDocs) {
+      fos |= FOS_DONTADDTORECENT;
+    }
+
+    // mode specific
+    switch (mMode) {
+      case modeOpen:
+        fos |= FOS_FILEMUSTEXIST;
+        break;
+
+      case modeOpenMultiple:
+        fos |= FOS_FILEMUSTEXIST | FOS_ALLOWMULTISELECT;
+        break;
+
+      case modeSave:
+        fos |= FOS_NOREADONLYRETURN;
+        // Don't follow shortcuts when saving a shortcut, this can be used
+        // to trick users (bug 271732)
+        if (IsDefaultPathLink()) fos |= FOS_NODEREFERENCELINKS;
+        break;
+
+      case modeGetFolder:
+        MOZ_ASSERT(false, "file-picker opened in directory-picker mode");
+        return NotOk(E_FAIL);
+    }
+
+    commands.AppendElement(fd::SetOptions(fos));
+  }
+
+  // initial strings
+
+  // title
+  commands.AppendElement(fd::SetTitle(mTitle));
+
+  // default filename
+  if (!mDefaultFilename.IsEmpty()) {
+    // Prevent the shell from expanding environment variables by removing
+    // the % characters that are used to delimit them.
+    nsAutoString sanitizedFilename(mDefaultFilename);
+    sanitizedFilename.ReplaceChar('%', '_');
+
+    commands.AppendElement(fd::SetFileName(sanitizedFilename));
+  }
+
+  // default extension to append to new files
+  if (!mDefaultExtension.IsEmpty()) {
+    // We don't want environment variables expanded in the extension either.
+    nsAutoString sanitizedExtension(mDefaultExtension);
+    sanitizedExtension.ReplaceChar('%', '_');
+
+    commands.AppendElement(fd::SetDefaultExtension(sanitizedExtension));
+  } else if (IsDefaultPathHtml()) {
+    commands.AppendElement(fd::SetDefaultExtension(u"html"_ns));
+  }
+
+  // initial location
+  if (!aInitialDir.IsEmpty()) {
+    commands.AppendElement(fd::SetFolder(aInitialDir));
+  }
+
+  // filter types and the default index
+  if (!mFilterList.IsEmpty()) {
+    nsTArray<fd::ComDlgFilterSpec> fileTypes;
+    for (auto const& filter : mFilterList) {
+      fileTypes.EmplaceBack(filter.title, filter.filter);
+    }
+    commands.AppendElement(fd::SetFileTypes(std::move(fileTypes)));
+    commands.AppendElement(fd::SetFileTypeIndex(mSelectedType));
+  }
+
+  ScopedRtlShimWindow shim(mParentWidget.get());
+  AutoWidgetPickerState awps(mParentWidget);
+
+  mozilla::BackgroundHangMonitor().NotifyWait();
+  auto type = mMode == modeSave ? FileDialogType::Save : FileDialogType::Open;
+
+  auto promise = mozilla::detail::AsyncExecute(
+      &ShowFilePickerLocal, &ShowFilePickerRemote, shim.get(), type, commands);
+
+  return promise->Then(
+      mozilla::GetMainThreadSerialEventTarget(), __PRETTY_FUNCTION__,
+      [self = RefPtr(this), mode = mMode, shim = std::move(shim),
+       awps = std::move(awps)](Maybe<Results> res_opt) {
+        if (!res_opt) {
+          return Ok(false);
+        }
+        auto result = res_opt.extract();
+
+        // Remember what filter type the user selected
+        self->mSelectedType = int32_t(result.selectedFileTypeIndex());
+
+        auto const& paths = result.paths();
+
+        // single selection
+        if (mode != modeOpenMultiple) {
+          if (!paths.IsEmpty()) {
+            MOZ_ASSERT(paths.Length() == 1);
+            self->mUnicodeFile = paths[0];
+            return Ok(true);
+          }
+          return Ok(false);
+        }
+
+        // multiple selection
+        for (auto const& str : paths) {
+          nsCOMPtr<nsIFile> file;
+          if (NS_SUCCEEDED(NS_NewLocalFile(str, false, getter_AddRefs(file)))) {
+            self->mFiles.AppendObject(file);
+          }
+        }
+
+        return Ok(true);
+      },
+      [](HRESULT err) {
+        NS_WARNING("ShowFilePicker failed");
+        return NotOk(err);
+      });
+}
+
+void nsFilePicker::ClearFiles() {
+  mUnicodeFile.Truncate();
+  mFiles.Clear();
+}
+
+namespace {
+class GetFilesInDirectoryCallback final
+    : public mozilla::dom::GetFilesCallback {
+ public:
+  explicit GetFilesInDirectoryCallback(
+      RefPtr<mozilla::MozPromise<nsTArray<mozilla::PathString>, nsresult,
+                                 true>::Private>
+          aPromise)
+      : mPromise(std::move(aPromise)) {}
+  void Callback(
+      nsresult aStatus,
+      const FallibleTArray<RefPtr<mozilla::dom::BlobImpl>>& aBlobImpls) {
+    if (NS_FAILED(aStatus)) {
+      mPromise->Reject(aStatus, __func__);
+      return;
+    }
+    nsTArray<mozilla::PathString> filePaths;
+    filePaths.SetCapacity(aBlobImpls.Length());
+    for (const auto& blob : aBlobImpls) {
+      if (blob->IsFile()) {
+        mozilla::PathString pathString;
+        mozilla::ErrorResult error;
+        blob->GetMozFullPathInternal(pathString, error);
+        nsresult rv = error.StealNSResult();
+        if (NS_WARN_IF(NS_FAILED(rv))) {
+          mPromise->Reject(rv, __func__);
+          return;
+        }
+        filePaths.AppendElement(pathString);
+      } else {
+        NS_WARNING("Got a non-file blob, can't do content analysis on it");
+      }
+    }
+    mPromise->Resolve(std::move(filePaths), __func__);
+  }
+
+ private:
+  RefPtr<mozilla::MozPromise<nsTArray<mozilla::PathString>, nsresult,
+                             true>::Private>
+      mPromise;
+};
+}  // anonymous namespace
+
+RefPtr<nsFilePicker::ContentAnalysisResponse>
+nsFilePicker::CheckContentAnalysisService() {
+  nsresult rv;
+  nsCOMPtr<nsIContentAnalysis> contentAnalysis =
+      mozilla::components::nsIContentAnalysis::Service(&rv);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return nsFilePicker::ContentAnalysisResponse::CreateAndReject(rv, __func__);
+  }
+  bool contentAnalysisIsActive = false;
+  rv = contentAnalysis->GetIsActive(&contentAnalysisIsActive);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return nsFilePicker::ContentAnalysisResponse::CreateAndReject(rv, __func__);
+  }
+  if (!contentAnalysisIsActive) {
+    return nsFilePicker::ContentAnalysisResponse::CreateAndResolve(true,
+                                                                   __func__);
+  }
+
+  nsCOMPtr<nsIURI> uri = mBrowsingContext->Canonical()->GetCurrentURI();
+
+  auto processOneItem = [self = RefPtr{this},
+                         contentAnalysis = std::move(contentAnalysis),
+                         uri =
+                             std::move(uri)](const mozilla::PathString& aItem) {
+    nsCString emptyDigestString;
+    auto* windowGlobal =
+        self->mBrowsingContext->Canonical()->GetCurrentWindowGlobal();
+    nsCOMPtr<nsIContentAnalysisRequest> contentAnalysisRequest(
+        new mozilla::contentanalysis::ContentAnalysisRequest(
+            nsIContentAnalysisRequest::AnalysisType::eFileAttached, aItem, true,
+            std::move(emptyDigestString), uri,
+            nsIContentAnalysisRequest::OperationType::eCustomDisplayString,
+            windowGlobal));
+
+    auto promise =
+        mozilla::MakeRefPtr<nsFilePicker::ContentAnalysisResponse::Private>(
+            __func__);
+    auto contentAnalysisCallback =
+        mozilla::MakeRefPtr<mozilla::contentanalysis::ContentAnalysisCallback>(
+            [promise](nsIContentAnalysisResponse* aResponse) {
+              promise->Resolve(aResponse->GetShouldAllowContent(), __func__);
+            },
+            [promise](nsresult aError) { promise->Reject(aError, __func__); });
+
+    nsresult rv = contentAnalysis->AnalyzeContentRequestCallback(
+        contentAnalysisRequest, /* aAutoAcknowledge */ true,
+        contentAnalysisCallback);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      promise->Reject(rv, __func__);
+    }
+    return promise;
+  };
+
+  // Since getting the files to analyze might be asynchronous, use a MozPromise
+  // to unify the logic below.
+  auto getFilesToAnalyzePromise = mozilla::MakeRefPtr<mozilla::MozPromise<
+      nsTArray<mozilla::PathString>, nsresult, true>::Private>(__func__);
+  if (mMode == modeGetFolder) {
+    nsCOMPtr<nsISupports> tmp;
+    nsresult rv = GetDomFileOrDirectory(getter_AddRefs(tmp));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      getFilesToAnalyzePromise->Reject(rv, __func__);
+      return nsFilePicker::ContentAnalysisResponse::CreateAndReject(rv,
+                                                                    __func__);
+    }
+    auto* directory = static_cast<mozilla::dom::Directory*>(tmp.get());
+    mozilla::dom::OwningFileOrDirectory owningDirectory;
+    owningDirectory.SetAsDirectory() = directory;
+    nsTArray<mozilla::dom::OwningFileOrDirectory> directoryArray{
+        std::move(owningDirectory)};
+
+    mozilla::ErrorResult error;
+    RefPtr<mozilla::dom::GetFilesHelper> helper =
+        mozilla::dom::GetFilesHelper::Create(directoryArray, true, error);
+    rv = error.StealNSResult();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      getFilesToAnalyzePromise->Reject(rv, __func__);
+      return nsFilePicker::ContentAnalysisResponse::CreateAndReject(rv,
+                                                                    __func__);
+    }
+    auto getFilesCallback = mozilla::MakeRefPtr<GetFilesInDirectoryCallback>(
+        getFilesToAnalyzePromise);
+    helper->AddCallback(getFilesCallback);
+  } else {
+    nsCOMArray<nsIFile> files;
+    if (!mUnicodeFile.IsEmpty()) {
+      nsCOMPtr<nsIFile> file;
+      rv = GetFile(getter_AddRefs(file));
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        getFilesToAnalyzePromise->Reject(rv, __func__);
+        return nsFilePicker::ContentAnalysisResponse::CreateAndReject(rv,
+                                                                      __func__);
+      }
+      files.AppendElement(file);
+    } else {
+      files.AppendElements(mFiles);
+    }
+    nsTArray<mozilla::PathString> paths(files.Length());
+    std::transform(files.begin(), files.end(), MakeBackInserter(paths),
+                   [](auto* entry) { return entry->NativePath(); });
+    getFilesToAnalyzePromise->Resolve(std::move(paths), __func__);
+  }
+
+  return getFilesToAnalyzePromise->Then(
+      mozilla::GetMainThreadSerialEventTarget(), __func__,
+      [processOneItem](nsTArray<mozilla::PathString> aPaths) mutable {
+        return mozilla::detail::AsyncAll<mozilla::PathString>(std::move(aPaths),
+                                                              processOneItem);
+      },
+      [](nsresult aError) {
+        return nsFilePicker::ContentAnalysisResponse::CreateAndReject(aError,
+                                                                      __func__);
+      });
+};
+
+///////////////////////////////////////////////////////////////////////////////
+// nsIFilePicker impl.
+
+nsresult nsFilePicker::Open(nsIFilePickerShownCallback* aCallback) {
+  NS_ENSURE_ARG_POINTER(aCallback);
+
+  if (MaybeBlockFilePicker(aCallback)) {
+    return NS_OK;
+  }
+
+  // Don't attempt to open a real file-picker in headless mode.
+  if (gfxPlatform::IsHeadless()) {
+    return nsresult::NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsAutoString initialDir;
+  if (mDisplayDirectory) mDisplayDirectory->GetPath(initialDir);
+
+  // If no display directory, re-use the last one.
+  if (initialDir.IsEmpty()) {
+    // Allocate copy of last used dir.
+    initialDir = sLastUsedUnicodeDirectory.get();
+  }
+
+  // Clear previous file selections
+  ClearFiles();
+
+  auto promise = mMode == modeGetFolder ? ShowFolderPicker(initialDir)
+                                        : ShowFilePicker(initialDir);
+
+  auto p2 = promise->Then(
+      mozilla::GetMainThreadSerialEventTarget(), __PRETTY_FUNCTION__,
+      [self = RefPtr(this),
+       callback = RefPtr(aCallback)](bool selectionMade) -> void {
+        if (!selectionMade) {
+          callback->Done(ResultCode::returnCancel);
+          return;
+        }
+
+        self->RememberLastUsedDirectory();
+
+        nsIFilePicker::ResultCode retValue = ResultCode::returnOK;
+
+        if (self->mMode == modeSave) {
+          // Windows does not return resultReplace; we must check whether the
+          // file already exists.
+          nsCOMPtr<nsIFile> file;
+          nsresult rv =
+              NS_NewLocalFile(self->mUnicodeFile, false, getter_AddRefs(file));
+
+          bool flag = false;
+          if (NS_SUCCEEDED(rv) && NS_SUCCEEDED(file->Exists(&flag)) && flag) {
+            retValue = ResultCode::returnReplace;
+          }
+        }
+
+        if (self->mBrowsingContext && !self->mBrowsingContext->IsChrome() &&
+            self->mMode != modeSave && retValue != ResultCode::returnCancel) {
+          self->CheckContentAnalysisService()->Then(
+              mozilla::GetMainThreadSerialEventTarget(), __func__,
+              [retValue, callback, self = RefPtr{self}](bool aAllowContent) {
+                if (aAllowContent) {
+                  callback->Done(retValue);
+                } else {
+                  self->ClearFiles();
+                  callback->Done(ResultCode::returnCancel);
+                }
+              },
+              [callback, self = RefPtr{self}](nsresult aError) {
+                self->ClearFiles();
+                callback->Done(ResultCode::returnCancel);
+              });
+          return;
+        }
+
+        callback->Done(retValue);
+      },
+      [callback = RefPtr(aCallback)](HRESULT err) {
+        using mozilla::widget::filedialog::sLogFileDialog;
+        MOZ_LOG(sLogFileDialog, LogLevel::Error,
+                ("nsFilePicker: Show failed with hr=0x%08lX", err));
+        callback->Done(ResultCode::returnCancel);
+      });
+
+  return NS_OK;
+}
+
+nsresult nsFilePicker::Show(nsIFilePicker::ResultCode* aReturnVal) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsFilePicker::GetFile(nsIFile** aFile) {
+  NS_ENSURE_ARG_POINTER(aFile);
+  *aFile = nullptr;
+
+  if (mUnicodeFile.IsEmpty()) return NS_OK;
+
+  nsCOMPtr<nsIFile> file;
+  nsresult rv = NS_NewLocalFile(mUnicodeFile, false, getter_AddRefs(file));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  file.forget(aFile);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePicker::GetFileURL(nsIURI** aFileURL) {
+  *aFileURL = nullptr;
+  nsCOMPtr<nsIFile> file;
+  nsresult rv = GetFile(getter_AddRefs(file));
+  if (!file) return rv;
+
+  return NS_NewFileURI(aFileURL, file);
+}
+
+NS_IMETHODIMP
+nsFilePicker::GetFiles(nsISimpleEnumerator** aFiles) {
+  NS_ENSURE_ARG_POINTER(aFiles);
+  return NS_NewArrayEnumerator(aFiles, mFiles, NS_GET_IID(nsIFile));
+}
+
+// Get the file + path
+NS_IMETHODIMP
+nsBaseWinFilePicker::SetDefaultString(const nsAString& aString) {
+  mDefaultFilePath = aString;
+
+  // First, make sure the file name is not too long.
+  int32_t nameLength;
+  int32_t nameIndex = mDefaultFilePath.RFind(u"\\");
+  if (nameIndex == kNotFound)
+    nameIndex = 0;
+  else
+    nameIndex++;
+  nameLength = mDefaultFilePath.Length() - nameIndex;
+  mDefaultFilename.Assign(Substring(mDefaultFilePath, nameIndex));
+
+  if (nameLength > MAX_PATH) {
+    int32_t extIndex = mDefaultFilePath.RFind(u".");
+    if (extIndex == kNotFound) extIndex = mDefaultFilePath.Length();
+
+    // Let's try to shave the needed characters from the name part.
+    int32_t charsToRemove = nameLength - MAX_PATH;
+    if (extIndex - nameIndex >= charsToRemove) {
+      mDefaultFilePath.Cut(extIndex - charsToRemove, charsToRemove);
+    }
+  }
+
+  // Then, we need to replace illegal characters. At this stage, we cannot
+  // replace the backslash as the string might represent a file path.
+  mDefaultFilePath.ReplaceChar(u"" FILE_ILLEGAL_CHARACTERS, u'-');
+  mDefaultFilename.ReplaceChar(u"" FILE_ILLEGAL_CHARACTERS, u'-');
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseWinFilePicker::GetDefaultString(nsAString& aString) {
+  return NS_ERROR_FAILURE;
+}
+
+// The default extension to use for files
+NS_IMETHODIMP
+nsBaseWinFilePicker::GetDefaultExtension(nsAString& aExtension) {
+  aExtension = mDefaultExtension;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseWinFilePicker::SetDefaultExtension(const nsAString& aExtension) {
+  mDefaultExtension = aExtension;
+  return NS_OK;
+}
+
+// Set the filter index
+NS_IMETHODIMP
+nsFilePicker::GetFilterIndex(int32_t* aFilterIndex) {
+  // Windows' filter index is 1-based, we use a 0-based system.
+  *aFilterIndex = mSelectedType - 1;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFilePicker::SetFilterIndex(int32_t aFilterIndex) {
+  // Windows' filter index is 1-based, we use a 0-based system.
+  mSelectedType = aFilterIndex + 1;
+  return NS_OK;
+}
+
+void nsFilePicker::InitNative(nsIWidget* aParent, const nsAString& aTitle) {
+  mParentWidget = aParent;
+  mTitle.Assign(aTitle);
+}
+
+NS_IMETHODIMP
+nsFilePicker::AppendFilter(const nsAString& aTitle, const nsAString& aFilter) {
+  nsString sanitizedFilter(aFilter);
+  sanitizedFilter.ReplaceChar('%', '_');
+
+  if (sanitizedFilter == u"..apps"_ns) {
+    sanitizedFilter = u"*.exe;*.com"_ns;
+  } else {
+    sanitizedFilter.StripWhitespace();
+    if (sanitizedFilter == u"*"_ns) {
+      sanitizedFilter = u"*.*"_ns;
+    }
+  }
+  mFilterList.AppendElement(
+      Filter{.title = nsString(aTitle), .filter = std::move(sanitizedFilter)});
+  return NS_OK;
+}
+
+void nsFilePicker::RememberLastUsedDirectory() {
+  if (IsPrivacyModeEnabled()) {
+    // Don't remember the directory if private browsing was in effect
+    return;
+  }
+
+  nsCOMPtr<nsIFile> file;
+  if (NS_FAILED(NS_NewLocalFile(mUnicodeFile, false, getter_AddRefs(file)))) {
+    NS_WARNING("RememberLastUsedDirectory failed to init file path.");
+    return;
+  }
+
+  nsCOMPtr<nsIFile> dir;
+  nsAutoString newDir;
+  if (NS_FAILED(file->GetParent(getter_AddRefs(dir))) ||
+      !(mDisplayDirectory = dir) ||
+      NS_FAILED(mDisplayDirectory->GetPath(newDir)) || newDir.IsEmpty()) {
+    NS_WARNING("RememberLastUsedDirectory failed to get parent directory.");
+    return;
+  }
+
+  sLastUsedUnicodeDirectory.reset(ToNewUnicode(newDir));
+}
+
+bool nsFilePicker::IsPrivacyModeEnabled() {
+  return mLoadContext && mLoadContext->UsePrivateBrowsing();
+}
+
+bool nsFilePicker::IsDefaultPathLink() {
+  NS_ConvertUTF16toUTF8 ext(mDefaultFilePath);
+  ext.Trim(" .", false, true);  // watch out for trailing space and dots
+  ToLowerCase(ext);
+  return StringEndsWith(ext, ".lnk"_ns) || StringEndsWith(ext, ".pif"_ns) ||
+         StringEndsWith(ext, ".url"_ns);
+}
+
+bool nsFilePicker::IsDefaultPathHtml() {
+  int32_t extIndex = mDefaultFilePath.RFind(u".");
+  if (extIndex >= 0) {
+    nsAutoString ext;
+    mDefaultFilePath.Right(ext, mDefaultFilePath.Length() - extIndex);
+    if (ext.LowerCaseEqualsLiteral(".htm") ||
+        ext.LowerCaseEqualsLiteral(".html") ||
+        ext.LowerCaseEqualsLiteral(".shtml"))
+      return true;
+  }
+  return false;
+}
diff --git a/widget/windows/nsFilePicker.h b/widget/windows/nsFilePicker.h
new file mode 100644
index 0000000000..1938b8bcb6
--- /dev/null
+++ b/widget/windows/nsFilePicker.h
@@ -0,0 +1,140 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsFilePicker_h__
+#define nsFilePicker_h__
+
+#include <windows.h>
+
+#include "mozilla/MozPromise.h"
+#include "mozilla/dom/BlobImpl.h"
+#include "mozilla/dom/BrowsingContext.h"
+#include "mozilla/dom/GetFilesHelper.h"
+#include "nsIContentAnalysis.h"
+#include "nsIFile.h"
+#include "nsISimpleEnumerator.h"
+#include "nsCOMArray.h"
+#include "nsBaseFilePicker.h"
+#include "nsString.h"
+#include "nsdefs.h"
+#include <commdlg.h>
+#include <shobjidl.h>
+#undef LogSeverity  // SetupAPI.h #defines this as DWORD
+
+class nsILoadContext;
+
+namespace mozilla::widget::filedialog {
+class Command;
+class Results;
+enum class FileDialogType : uint8_t;
+}  // namespace mozilla::widget::filedialog
+
+class nsBaseWinFilePicker : public nsBaseFilePicker {
+ public:
+  NS_IMETHOD GetDefaultString(nsAString& aDefaultString) override;
+  NS_IMETHOD SetDefaultString(const nsAString& aDefaultString) override;
+  NS_IMETHOD GetDefaultExtension(nsAString& aDefaultExtension) override;
+  NS_IMETHOD SetDefaultExtension(const nsAString& aDefaultExtension) override;
+
+ protected:
+  nsString mDefaultFilePath;
+  nsString mDefaultFilename;
+  nsString mDefaultExtension;
+};
+
+/**
+ * Native Windows FileSelector wrapper
+ */
+
+class nsFilePicker final : public nsBaseWinFilePicker {
+  virtual ~nsFilePicker() = default;
+
+  template <typename T>
+  using Maybe = mozilla::Maybe<T>;
+  template <typename T>
+  using Result = mozilla::Result<T, HRESULT>;
+  template <typename Res>
+  using FPPromise = RefPtr<mozilla::MozPromise<Maybe<Res>, HRESULT, true>>;
+
+  using Command = mozilla::widget::filedialog::Command;
+  using Results = mozilla::widget::filedialog::Results;
+  using FileDialogType = mozilla::widget::filedialog::FileDialogType;
+
+ public:
+  nsFilePicker();
+
+  NS_IMETHOD Init(mozIDOMWindowProxy* aParent, const nsAString& aTitle,
+                  nsIFilePicker::Mode aMode,
+                  mozilla::dom::BrowsingContext* aBrowsingContext) override;
+
+  NS_DECL_ISUPPORTS
+
+  // nsIFilePicker (less what's in nsBaseFilePicker and nsBaseWinFilePicker)
+  NS_IMETHOD GetFilterIndex(int32_t* aFilterIndex) override;
+  NS_IMETHOD SetFilterIndex(int32_t aFilterIndex) override;
+  NS_IMETHOD GetFile(nsIFile** aFile) override;
+  NS_IMETHOD GetFileURL(nsIURI** aFileURL) override;
+  NS_IMETHOD GetFiles(nsISimpleEnumerator** aFiles) override;
+  NS_IMETHOD AppendFilter(const nsAString& aTitle,
+                          const nsAString& aFilter) override;
+
+ protected:
+  /* method from nsBaseFilePicker */
+  virtual void InitNative(nsIWidget* aParent, const nsAString& aTitle) override;
+  nsresult Show(nsIFilePicker::ResultCode* aReturnVal) override;
+  void GetFilterListArray(nsString& aFilterList);
+
+  NS_IMETHOD Open(nsIFilePickerShownCallback* aCallback) override;
+
+ private:
+  RefPtr<mozilla::MozPromise<bool, HRESULT, true>> ShowFolderPicker(
+      const nsString& aInitialDir);
+  RefPtr<mozilla::MozPromise<bool, HRESULT, true>> ShowFilePicker(
+      const nsString& aInitialDir);
+
+  // Show the dialog out-of-process.
+  static FPPromise<Results> ShowFilePickerRemote(
+      HWND aParent, FileDialogType type, nsTArray<Command> const& commands);
+  static FPPromise<nsString> ShowFolderPickerRemote(
+      HWND aParent, nsTArray<Command> const& commands);
+
+  // Show the dialog in-process.
+  static FPPromise<Results> ShowFilePickerLocal(
+      HWND aParent, FileDialogType type, nsTArray<Command> const& commands);
+  static FPPromise<nsString> ShowFolderPickerLocal(
+      HWND aParent, nsTArray<Command> const& commands);
+
+  void ClearFiles();
+  using ContentAnalysisResponse = mozilla::MozPromise<bool, nsresult, true>;
+  RefPtr<ContentAnalysisResponse> CheckContentAnalysisService();
+
+ protected:
+  void RememberLastUsedDirectory();
+  bool IsPrivacyModeEnabled();
+  bool IsDefaultPathLink();
+  bool IsDefaultPathHtml();
+
+  nsCOMPtr<nsILoadContext> mLoadContext;
+  nsCOMPtr<nsIWidget> mParentWidget;
+  nsString mTitle;
+  nsCString mFile;
+  int32_t mSelectedType;
+  nsCOMArray<nsIFile> mFiles;
+  nsString mUnicodeFile;
+
+  struct FreeDeleter {
+    void operator()(void* aPtr) { ::free(aPtr); }
+  };
+  static mozilla::UniquePtr<char16_t[], FreeDeleter> sLastUsedUnicodeDirectory;
+
+  struct Filter {
+    nsString title;
+    nsString filter;
+  };
+  AutoTArray<Filter, 1> mFilterList;
+};
+
+#endif  // nsFilePicker_h__
diff --git a/widget/windows/nsLookAndFeel.cpp b/widget/windows/nsLookAndFeel.cpp
new file mode 100644
index 0000000000..01b126cd42
--- /dev/null
+++ b/widget/windows/nsLookAndFeel.cpp
@@ -0,0 +1,916 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsLookAndFeel.h"
+#include <stdint.h>
+#include <windows.h>
+#include <shellapi.h>
+#include "nsStyleConsts.h"
+#include "nsUXThemeData.h"
+#include "nsUXThemeConstants.h"
+#include "nsWindowsHelpers.h"
+#include "WinUtils.h"
+#include "WindowsUIUtils.h"
+#include "mozilla/FontPropertyTypes.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/widget/WinRegistry.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+static Maybe<nscolor> GetColorFromTheme(nsUXThemeClass cls, int32_t aPart,
+                                        int32_t aState, int32_t aPropId) {
+  COLORREF color;
+  HRESULT hr = GetThemeColor(nsUXThemeData::GetTheme(cls), aPart, aState,
+                             aPropId, &color);
+  if (hr == S_OK) {
+    return Some(COLOREF_2_NSRGB(color));
+  }
+  return Nothing();
+}
+
+static int32_t GetSystemParam(long flag, int32_t def) {
+  DWORD value;
+  return ::SystemParametersInfo(flag, 0, &value, 0) ? value : def;
+}
+
+static bool SystemWantsDarkTheme() {
+  if (nsUXThemeData::IsHighContrastOn()) {
+    return LookAndFeel::IsDarkColor(
+        LookAndFeel::Color(StyleSystemColor::Window, ColorScheme::Light,
+                           LookAndFeel::UseStandins::No));
+  }
+
+  WinRegistry::Key key(
+      HKEY_CURRENT_USER,
+      u"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Themes\\Personalize"_ns,
+      WinRegistry::KeyMode::QueryValue);
+  if (NS_WARN_IF(!key)) {
+    return false;
+  }
+  uint32_t light = key.GetValueAsDword(u"AppsUseLightTheme"_ns).valueOr(1);
+  return !light;
+}
+
+uint32_t nsLookAndFeel::SystemColorFilter() {
+  if (NS_WARN_IF(!mColorFilterWatcher)) {
+    return 0;
+  }
+
+  const auto& key = mColorFilterWatcher->GetKey();
+  if (!key.GetValueAsDword(u"Active"_ns).valueOr(0)) {
+    return 0;
+  }
+  return key.GetValueAsDword(u"FilterType"_ns).valueOr(0);
+}
+
+nsLookAndFeel::nsLookAndFeel() {
+  mozilla::Telemetry::Accumulate(mozilla::Telemetry::TOUCH_ENABLED_DEVICE,
+                                 WinUtils::IsTouchDeviceSupportPresent());
+}
+
+nsLookAndFeel::~nsLookAndFeel() = default;
+
+void nsLookAndFeel::NativeInit() { EnsureInit(); }
+
+/* virtual */
+void nsLookAndFeel::RefreshImpl() {
+  mInitialized = false;  // Fetch system colors next time they're used.
+  nsXPLookAndFeel::RefreshImpl();
+}
+
+static bool UseNonNativeMenuColors(ColorScheme aScheme) {
+  return !LookAndFeel::GetInt(LookAndFeel::IntID::UseAccessibilityTheme) ||
+         aScheme == ColorScheme::Dark;
+}
+
+nsresult nsLookAndFeel::NativeGetColor(ColorID aID, ColorScheme aScheme,
+                                       nscolor& aColor) {
+  EnsureInit();
+
+  auto IsHighlightColor = [&] {
+    switch (aID) {
+      case ColorID::MozMenuhover:
+        return !UseNonNativeMenuColors(aScheme);
+      case ColorID::Highlight:
+      case ColorID::Selecteditem:
+        // We prefer the generic dark selection color if we don't have an
+        // explicit one.
+        return aScheme != ColorScheme::Dark || mDarkHighlight;
+      case ColorID::IMESelectedRawTextBackground:
+      case ColorID::IMESelectedConvertedTextBackground:
+        return true;
+      default:
+        return false;
+    }
+  };
+
+  auto IsHighlightTextColor = [&] {
+    switch (aID) {
+      case ColorID::MozMenubarhovertext:
+        if (UseNonNativeMenuColors(aScheme)) {
+          return false;
+        }
+        [[fallthrough]];
+      case ColorID::MozMenuhovertext:
+        if (UseNonNativeMenuColors(aScheme)) {
+          return false;
+        }
+        return !mColorMenuHoverText;
+      case ColorID::Highlighttext:
+      case ColorID::Selecteditemtext:
+        // We prefer the generic dark selection color if we don't have an
+        // explicit one.
+        return aScheme != ColorScheme::Dark || mDarkHighlightText;
+      case ColorID::IMESelectedRawTextForeground:
+      case ColorID::IMESelectedConvertedTextForeground:
+        return true;
+      default:
+        return false;
+    }
+  };
+
+  if (IsHighlightColor()) {
+    if (aScheme == ColorScheme::Dark && mDarkHighlight) {
+      aColor = *mDarkHighlight;
+    } else {
+      aColor = GetColorForSysColorIndex(COLOR_HIGHLIGHT);
+    }
+    return NS_OK;
+  }
+
+  if (IsHighlightTextColor()) {
+    if (aScheme == ColorScheme::Dark && mDarkHighlightText) {
+      aColor = *mDarkHighlightText;
+    } else {
+      aColor = GetColorForSysColorIndex(COLOR_HIGHLIGHTTEXT);
+    }
+    return NS_OK;
+  }
+
+  // Titlebar colors are color-scheme aware.
+  switch (aID) {
+    case ColorID::Activecaption:
+      aColor = mTitlebarColors.Get(aScheme, true).mBg;
+      return NS_OK;
+    case ColorID::Captiontext:
+      aColor = mTitlebarColors.Get(aScheme, true).mFg;
+      return NS_OK;
+    case ColorID::Activeborder:
+      aColor = mTitlebarColors.Get(aScheme, true).mBorder;
+      return NS_OK;
+    case ColorID::Inactivecaption:
+      aColor = mTitlebarColors.Get(aScheme, false).mBg;
+      return NS_OK;
+    case ColorID::Inactivecaptiontext:
+      aColor = mTitlebarColors.Get(aScheme, false).mFg;
+      return NS_OK;
+    case ColorID::Inactiveborder:
+      aColor = mTitlebarColors.Get(aScheme, false).mBorder;
+      return NS_OK;
+    default:
+      break;
+  }
+
+  if (aScheme == ColorScheme::Dark) {
+    if (auto color = GenericDarkColor(aID)) {
+      aColor = *color;
+      return NS_OK;
+    }
+  }
+
+  static constexpr auto kNonNativeMenuText = NS_RGB(0x15, 0x14, 0x1a);
+  nsresult res = NS_OK;
+  int idx;
+  switch (aID) {
+    case ColorID::IMERawInputBackground:
+    case ColorID::IMEConvertedTextBackground:
+      aColor = NS_TRANSPARENT;
+      return NS_OK;
+    case ColorID::IMERawInputForeground:
+    case ColorID::IMEConvertedTextForeground:
+      aColor = NS_SAME_AS_FOREGROUND_COLOR;
+      return NS_OK;
+    case ColorID::IMERawInputUnderline:
+    case ColorID::IMEConvertedTextUnderline:
+      aColor = NS_SAME_AS_FOREGROUND_COLOR;
+      return NS_OK;
+    case ColorID::IMESelectedRawTextUnderline:
+    case ColorID::IMESelectedConvertedTextUnderline:
+      aColor = NS_TRANSPARENT;
+      return NS_OK;
+
+    // New CSS 2 Color definitions
+    case ColorID::Appworkspace:
+      idx = COLOR_APPWORKSPACE;
+      break;
+    case ColorID::Background:
+      idx = COLOR_BACKGROUND;
+      break;
+    case ColorID::Buttonface:
+    case ColorID::MozButtonhoverface:
+    case ColorID::MozButtonactiveface:
+    case ColorID::MozButtondisabledface:
+    case ColorID::MozColheader:
+    case ColorID::MozColheaderhover:
+    case ColorID::MozColheaderactive:
+      idx = COLOR_BTNFACE;
+      break;
+    case ColorID::Buttonhighlight:
+      idx = COLOR_BTNHIGHLIGHT;
+      break;
+    case ColorID::Buttonshadow:
+      idx = COLOR_BTNSHADOW;
+      break;
+    case ColorID::Buttontext:
+    case ColorID::MozButtonhovertext:
+    case ColorID::MozButtonactivetext:
+      idx = COLOR_BTNTEXT;
+      break;
+    case ColorID::MozCellhighlighttext:
+      aColor = NS_RGB(0, 0, 0);
+      return NS_OK;
+    case ColorID::MozCellhighlight:
+      aColor = NS_RGB(206, 206, 206);
+      return NS_OK;
+    case ColorID::Graytext:
+      idx = COLOR_GRAYTEXT;
+      break;
+    case ColorID::MozMenubarhovertext:
+      if (UseNonNativeMenuColors(aScheme)) {
+        aColor = kNonNativeMenuText;
+        return NS_OK;
+      }
+      [[fallthrough]];
+    case ColorID::MozMenuhovertext:
+      if (UseNonNativeMenuColors(aScheme)) {
+        aColor = kNonNativeMenuText;
+        return NS_OK;
+      }
+      if (mColorMenuHoverText) {
+        aColor = *mColorMenuHoverText;
+        return NS_OK;
+      }
+      idx = COLOR_HIGHLIGHTTEXT;
+      break;
+    case ColorID::MozMenuhover:
+      MOZ_ASSERT(UseNonNativeMenuColors(aScheme));
+      aColor = NS_RGB(0xe0, 0xe0, 0xe6);
+      return NS_OK;
+    case ColorID::MozMenuhoverdisabled:
+      if (UseNonNativeMenuColors(aScheme)) {
+        aColor = NS_RGB(0xf0, 0xf0, 0xf3);
+        return NS_OK;
+      }
+      aColor = NS_TRANSPARENT;
+      return NS_OK;
+    case ColorID::Infobackground:
+      idx = COLOR_INFOBK;
+      break;
+    case ColorID::Infotext:
+      idx = COLOR_INFOTEXT;
+      break;
+    case ColorID::Menu:
+      if (UseNonNativeMenuColors(aScheme)) {
+        aColor = NS_RGB(0xf9, 0xf9, 0xfb);
+        return NS_OK;
+      }
+      idx = COLOR_MENU;
+      break;
+    case ColorID::Menutext:
+      if (UseNonNativeMenuColors(aScheme)) {
+        aColor = kNonNativeMenuText;
+        return NS_OK;
+      }
+      idx = COLOR_MENUTEXT;
+      break;
+    case ColorID::Scrollbar:
+      idx = COLOR_SCROLLBAR;
+      break;
+    case ColorID::Threeddarkshadow:
+      idx = COLOR_3DDKSHADOW;
+      break;
+    case ColorID::Threedface:
+      idx = COLOR_3DFACE;
+      break;
+    case ColorID::Threedhighlight:
+      idx = COLOR_3DHIGHLIGHT;
+      break;
+    case ColorID::Threedlightshadow:
+    case ColorID::Buttonborder:
+    case ColorID::MozDisabledfield:
+    case ColorID::MozSidebarborder:
+      idx = COLOR_3DLIGHT;
+      break;
+    case ColorID::Threedshadow:
+      idx = COLOR_3DSHADOW;
+      break;
+    case ColorID::Window:
+      idx = COLOR_WINDOW;
+      break;
+    case ColorID::Windowframe:
+      idx = COLOR_WINDOWFRAME;
+      break;
+    case ColorID::Windowtext:
+      idx = COLOR_WINDOWTEXT;
+      break;
+    case ColorID::MozEventreerow:
+    case ColorID::MozOddtreerow:
+    case ColorID::Field:
+    case ColorID::MozSidebar:
+    case ColorID::MozCombobox:
+      idx = COLOR_WINDOW;
+      break;
+    case ColorID::Fieldtext:
+    case ColorID::MozSidebartext:
+    case ColorID::MozComboboxtext:
+      idx = COLOR_WINDOWTEXT;
+      break;
+    case ColorID::MozHeaderbar:
+    case ColorID::MozHeaderbarinactive:
+    case ColorID::MozDialog:
+      idx = COLOR_3DFACE;
+      break;
+    case ColorID::Accentcolor:
+      aColor = mColorAccent;
+      return NS_OK;
+    case ColorID::Accentcolortext:
+      aColor = mColorAccentText;
+      return NS_OK;
+    case ColorID::MozHeaderbartext:
+    case ColorID::MozHeaderbarinactivetext:
+    case ColorID::MozDialogtext:
+    case ColorID::MozColheadertext:
+    case ColorID::MozColheaderhovertext:
+    case ColorID::MozColheaderactivetext:
+      idx = COLOR_WINDOWTEXT;
+      break;
+    case ColorID::MozNativehyperlinktext:
+      idx = COLOR_HOTLIGHT;
+      break;
+    case ColorID::Marktext:
+    case ColorID::Mark:
+    case ColorID::SpellCheckerUnderline:
+      aColor = GetStandinForNativeColor(aID, aScheme);
+      return NS_OK;
+    default:
+      idx = COLOR_WINDOW;
+      res = NS_ERROR_FAILURE;
+      break;
+  }
+
+  aColor = GetColorForSysColorIndex(idx);
+
+  return res;
+}
+
+nsresult nsLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
+  EnsureInit();
+  nsresult res = NS_OK;
+
+  switch (aID) {
+    case IntID::ScrollButtonLeftMouseButtonAction:
+      aResult = 0;
+      break;
+    case IntID::ScrollButtonMiddleMouseButtonAction:
+    case IntID::ScrollButtonRightMouseButtonAction:
+      aResult = 3;
+      break;
+    case IntID::CaretBlinkTime:
+      aResult = static_cast<int32_t>(::GetCaretBlinkTime());
+      break;
+    case IntID::CaretBlinkCount: {
+      int32_t timeout = GetSystemParam(SPI_GETCARETTIMEOUT, 5000);
+      auto blinkTime = ::GetCaretBlinkTime();
+      if (timeout <= 0 || blinkTime <= 0) {
+        aResult = -1;
+        break;
+      }
+      // 2 * blinkTime because this integer is a full blink cycle.
+      aResult = std::ceil(float(timeout) / (2.0f * float(blinkTime)));
+      break;
+    }
+
+    case IntID::CaretWidth:
+      aResult = 1;
+      break;
+    case IntID::ShowCaretDuringSelection:
+      aResult = 0;
+      break;
+    case IntID::SelectTextfieldsOnKeyFocus:
+      // Select textfield content when focused by kbd
+      // used by EventStateManager::sTextfieldSelectModel
+      aResult = 1;
+      break;
+    case IntID::SubmenuDelay:
+      // This will default to the Windows' default
+      // (400ms) on error.
+      aResult = GetSystemParam(SPI_GETMENUSHOWDELAY, 400);
+      break;
+    case IntID::TooltipDelay:
+      aResult = 500;
+      break;
+    case IntID::MenusCanOverlapOSBar:
+      // we want XUL popups to be able to overlap the task bar.
+      aResult = 1;
+      break;
+    case IntID::DragThresholdX:
+      // The system metric is the number of pixels at which a drag should
+      // start.  Our look and feel metric is the number of pixels you can
+      // move before starting a drag, so subtract 1.
+      aResult = ::GetSystemMetrics(SM_CXDRAG) - 1;
+      break;
+    case IntID::DragThresholdY:
+      aResult = ::GetSystemMetrics(SM_CYDRAG) - 1;
+      break;
+    case IntID::UseAccessibilityTheme:
+      // High contrast is a misnomer under Win32 -- any theme can be used with
+      // it, e.g. normal contrast with large fonts, low contrast, etc. The high
+      // contrast flag really means -- use this theme and don't override it.
+      aResult = nsUXThemeData::IsHighContrastOn();
+      break;
+    case IntID::ScrollArrowStyle:
+      aResult = eScrollArrowStyle_Single;
+      break;
+    case IntID::TreeOpenDelay:
+      aResult = 1000;
+      break;
+    case IntID::TreeCloseDelay:
+      aResult = 0;
+      break;
+    case IntID::TreeLazyScrollDelay:
+      aResult = 150;
+      break;
+    case IntID::TreeScrollDelay:
+      aResult = 100;
+      break;
+    case IntID::TreeScrollLinesMax:
+      aResult = 3;
+      break;
+    case IntID::WindowsAccentColorInTitlebar: {
+      aResult = mTitlebarColors.mUseAccent;
+    } break;
+    case IntID::AlertNotificationOrigin:
+      aResult = 0;
+      {
+        // Get task bar window handle
+        HWND shellWindow = FindWindowW(L"Shell_TrayWnd", nullptr);
+
+        if (shellWindow != nullptr) {
+          // Determine position
+          APPBARDATA appBarData;
+          appBarData.hWnd = shellWindow;
+          appBarData.cbSize = sizeof(appBarData);
+          if (SHAppBarMessage(ABM_GETTASKBARPOS, &appBarData)) {
+            // Set alert origin as a bit field - see LookAndFeel.h
+            // 0 represents bottom right, sliding vertically.
+            switch (appBarData.uEdge) {
+              case ABE_LEFT:
+                aResult = NS_ALERT_HORIZONTAL | NS_ALERT_LEFT;
+                break;
+              case ABE_RIGHT:
+                aResult = NS_ALERT_HORIZONTAL;
+                break;
+              case ABE_TOP:
+                aResult = NS_ALERT_TOP;
+                [[fallthrough]];
+              case ABE_BOTTOM:
+                // If the task bar is right-to-left,
+                // move the origin to the left
+                if (::GetWindowLong(shellWindow, GWL_EXSTYLE) & WS_EX_LAYOUTRTL)
+                  aResult |= NS_ALERT_LEFT;
+                break;
+            }
+          }
+        }
+      }
+      break;
+    case IntID::IMERawInputUnderlineStyle:
+    case IntID::IMEConvertedTextUnderlineStyle:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Dashed);
+      break;
+    case IntID::IMESelectedRawTextUnderlineStyle:
+    case IntID::IMESelectedConvertedTextUnderline:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::None);
+      break;
+    case IntID::SpellCheckerUnderlineStyle:
+      aResult = static_cast<int32_t>(StyleTextDecorationStyle::Wavy);
+      break;
+    case IntID::ScrollbarButtonAutoRepeatBehavior:
+      aResult = 0;
+      break;
+    case IntID::SwipeAnimationEnabled:
+      // Forcibly enable the swipe animation on Windows. It doesn't matter on
+      // platforms where "Drag two fingers to scroll" isn't supported since on
+      // the platforms we will never generate any swipe gesture events.
+      aResult = 1;
+      break;
+    case IntID::UseOverlayScrollbars:
+      aResult = WindowsUIUtils::ComputeOverlayScrollbars();
+      break;
+    case IntID::AllowOverlayScrollbarsOverlap:
+      aResult = 0;
+      break;
+    case IntID::ScrollbarDisplayOnMouseMove:
+      aResult = 1;
+      break;
+    case IntID::ScrollbarFadeBeginDelay:
+      aResult = 2500;
+      break;
+    case IntID::ScrollbarFadeDuration:
+      aResult = 350;
+      break;
+    case IntID::ContextMenuOffsetVertical:
+    case IntID::ContextMenuOffsetHorizontal:
+      aResult = 2;
+      break;
+    case IntID::SystemUsesDarkTheme:
+      aResult = SystemWantsDarkTheme();
+      break;
+    case IntID::SystemScrollbarSize:
+      aResult = std::max(WinUtils::GetSystemMetricsForDpi(SM_CXVSCROLL, 96),
+                         WinUtils::GetSystemMetricsForDpi(SM_CXHSCROLL, 96));
+      break;
+    case IntID::PrefersReducedMotion: {
+      BOOL enable = TRUE;
+      ::SystemParametersInfoW(SPI_GETCLIENTAREAANIMATION, 0, &enable, 0);
+      aResult = !enable;
+      break;
+    }
+    case IntID::PrefersReducedTransparency: {
+      // Prefers reduced transparency if the option for "Transparency Effects"
+      // is disabled
+      aResult = !WindowsUIUtils::ComputeTransparencyEffects();
+      break;
+    }
+    case IntID::InvertedColors: {
+      // Color filter values
+      // 1: Inverted
+      // 2: Grayscale inverted
+      aResult = mCurrentColorFilter == 1 || mCurrentColorFilter == 2;
+      break;
+    }
+    case IntID::PrimaryPointerCapabilities: {
+      aResult = static_cast<int32_t>(
+          widget::WinUtils::GetPrimaryPointerCapabilities());
+      break;
+    }
+    case IntID::AllPointerCapabilities: {
+      aResult =
+          static_cast<int32_t>(widget::WinUtils::GetAllPointerCapabilities());
+      break;
+    }
+    case IntID::TouchDeviceSupportPresent:
+      aResult = !!WinUtils::IsTouchDeviceSupportPresent();
+      break;
+    case IntID::PanelAnimations:
+      aResult = 1;
+      break;
+    case IntID::HideCursorWhileTyping: {
+      BOOL enable = TRUE;
+      ::SystemParametersInfoW(SPI_GETMOUSEVANISH, 0, &enable, 0);
+      aResult = enable;
+      break;
+    }
+    default:
+      aResult = 0;
+      res = NS_ERROR_FAILURE;
+  }
+  return res;
+}
+
+nsresult nsLookAndFeel::NativeGetFloat(FloatID aID, float& aResult) {
+  nsresult res = NS_OK;
+
+  switch (aID) {
+    case FloatID::IMEUnderlineRelativeSize:
+      aResult = 1.0f;
+      break;
+    case FloatID::SpellCheckerUnderlineRelativeSize:
+      aResult = 1.0f;
+      break;
+    case FloatID::TextScaleFactor:
+      aResult = WindowsUIUtils::ComputeTextScaleFactor();
+      break;
+    default:
+      aResult = -1.0;
+      res = NS_ERROR_FAILURE;
+  }
+  return res;
+}
+
+LookAndFeelFont nsLookAndFeel::GetLookAndFeelFontInternal(
+    const LOGFONTW& aLogFont, bool aUseShellDlg) {
+  LookAndFeelFont result{};
+
+  result.haveFont() = false;
+
+  // Get scaling factor from physical to logical pixels
+  double pixelScale =
+      1.0 / WinUtils::SystemScaleFactor() / LookAndFeel::GetTextScaleFactor();
+
+  // The lfHeight is in pixels, and it needs to be adjusted for the
+  // device it will be displayed on.
+  // Screens and Printers will differ in DPI
+  //
+  // So this accounts for the difference in the DeviceContexts
+  // The pixelScale will typically be 1.0 for the screen
+  // (though larger for hi-dpi screens where the Windows resolution
+  // scale factor is 125% or 150% or even more), and could be
+  // any value when going to a printer, for example pixelScale is
+  // 6.25 when going to a 600dpi printer.
+  float pixelHeight = -aLogFont.lfHeight;
+  if (pixelHeight < 0) {
+    nsAutoFont hFont(::CreateFontIndirectW(&aLogFont));
+    if (!hFont) {
+      return result;
+    }
+
+    nsAutoHDC dc(::GetDC(nullptr));
+    HGDIOBJ hObject = ::SelectObject(dc, hFont);
+    TEXTMETRIC tm;
+    ::GetTextMetrics(dc, &tm);
+    ::SelectObject(dc, hObject);
+
+    pixelHeight = tm.tmAscent;
+  }
+
+  pixelHeight *= pixelScale;
+
+  // we have problem on Simplified Chinese system because the system
+  // report the default font size is 8 points. but if we use 8, the text
+  // display very ugly. force it to be at 9 points (12 pixels) on that
+  // system (cp936), but leave other sizes alone.
+  if (pixelHeight < 12 && ::GetACP() == 936) {
+    pixelHeight = 12;
+  }
+
+  result.haveFont() = true;
+
+  if (aUseShellDlg) {
+    result.name() = u"MS Shell Dlg 2"_ns;
+  } else {
+    result.name() = aLogFont.lfFaceName;
+  }
+
+  result.size() = pixelHeight;
+  result.italic() = !!aLogFont.lfItalic;
+  // FIXME: Other weights?
+  result.weight() =
+      ((aLogFont.lfWeight == FW_BOLD) ? FontWeight::BOLD : FontWeight::NORMAL)
+          .ToFloat();
+
+  return result;
+}
+
+LookAndFeelFont nsLookAndFeel::GetLookAndFeelFont(LookAndFeel::FontID anID) {
+  LookAndFeelFont result{};
+
+  result.haveFont() = false;
+
+  // FontID::Icon is handled differently than the others
+  if (anID == LookAndFeel::FontID::Icon) {
+    LOGFONTW logFont;
+    if (::SystemParametersInfoW(SPI_GETICONTITLELOGFONT, sizeof(logFont),
+                                (PVOID)&logFont, 0)) {
+      result = GetLookAndFeelFontInternal(logFont, false);
+    }
+    return result;
+  }
+
+  NONCLIENTMETRICSW ncm;
+  ncm.cbSize = sizeof(NONCLIENTMETRICSW);
+  if (!::SystemParametersInfoW(SPI_GETNONCLIENTMETRICS, sizeof(ncm),
+                               (PVOID)&ncm, 0)) {
+    return result;
+  }
+
+  switch (anID) {
+    case LookAndFeel::FontID::Menu:
+    case LookAndFeel::FontID::MozPullDownMenu:
+      result = GetLookAndFeelFontInternal(ncm.lfMenuFont, false);
+      break;
+    case LookAndFeel::FontID::Caption:
+      result = GetLookAndFeelFontInternal(ncm.lfCaptionFont, false);
+      break;
+    case LookAndFeel::FontID::SmallCaption:
+      result = GetLookAndFeelFontInternal(ncm.lfSmCaptionFont, false);
+      break;
+    case LookAndFeel::FontID::StatusBar:
+      result = GetLookAndFeelFontInternal(ncm.lfStatusFont, false);
+      break;
+    case LookAndFeel::FontID::MozButton:
+    case LookAndFeel::FontID::MozField:
+    case LookAndFeel::FontID::MozList:
+      // XXX It's not clear to me whether this is exactly the right
+      // set of LookAndFeel values to map to the dialog font; we may
+      // want to add or remove cases here after reviewing the visual
+      // results under various Windows versions.
+      result = GetLookAndFeelFontInternal(ncm.lfMessageFont, true);
+      break;
+    default:
+      result = GetLookAndFeelFontInternal(ncm.lfMessageFont, false);
+      break;
+  }
+
+  return result;
+}
+
+bool nsLookAndFeel::NativeGetFont(LookAndFeel::FontID anID, nsString& aFontName,
+                                  gfxFontStyle& aFontStyle) {
+  LookAndFeelFont font = GetLookAndFeelFont(anID);
+  return LookAndFeelFontToStyle(font, aFontName, aFontStyle);
+}
+
+/* virtual */
+char16_t nsLookAndFeel::GetPasswordCharacterImpl() {
+#define UNICODE_BLACK_CIRCLE_CHAR 0x25cf
+  return UNICODE_BLACK_CIRCLE_CHAR;
+}
+
+static nscolor GetAccentColorText(const nscolor aAccentColor) {
+  // We want the color that we return for text that will be drawn over
+  // a background that has the accent color to have good contrast with
+  // the accent color.  Windows itself uses either white or black text
+  // depending on how light or dark the accent color is.  We do the same
+  // here based on the luminance of the accent color with a threshhold
+  // value.  This algorithm should match what Windows does.  It comes from:
+  //
+  // https://docs.microsoft.com/en-us/windows/uwp/style/color
+  float luminance = (NS_GET_R(aAccentColor) * 2 + NS_GET_G(aAccentColor) * 5 +
+                     NS_GET_B(aAccentColor)) /
+                    8;
+  return luminance <= 128 ? NS_RGB(255, 255, 255) : NS_RGB(0, 0, 0);
+}
+
+static Maybe<nscolor> GetAccentColorText(const Maybe<nscolor>& aAccentColor) {
+  if (!aAccentColor) {
+    return Nothing();
+  }
+  return Some(GetAccentColorText(*aAccentColor));
+}
+
+nscolor nsLookAndFeel::GetColorForSysColorIndex(int index) {
+  MOZ_ASSERT(index >= SYS_COLOR_MIN && index <= SYS_COLOR_MAX);
+  return mSysColorTable[index - SYS_COLOR_MIN];
+}
+
+auto nsLookAndFeel::ComputeTitlebarColors() -> TitlebarColors {
+  TitlebarColors result;
+
+  // Start with the native / non-accent-in-titlebar colors.
+  result.mActiveLight = {GetColorForSysColorIndex(COLOR_ACTIVECAPTION),
+                         GetColorForSysColorIndex(COLOR_CAPTIONTEXT),
+                         GetColorForSysColorIndex(COLOR_ACTIVEBORDER)};
+
+  result.mInactiveLight = {GetColorForSysColorIndex(COLOR_INACTIVECAPTION),
+                           GetColorForSysColorIndex(COLOR_INACTIVECAPTIONTEXT),
+                           GetColorForSysColorIndex(COLOR_INACTIVEBORDER)};
+
+  if (!nsUXThemeData::IsHighContrastOn()) {
+    // Use our non-native colors.
+    result.mActiveLight = {
+        GetStandinForNativeColor(ColorID::Activecaption, ColorScheme::Light),
+        GetStandinForNativeColor(ColorID::Captiontext, ColorScheme::Light),
+        GetStandinForNativeColor(ColorID::Activeborder, ColorScheme::Light)};
+    result.mInactiveLight = {
+        GetStandinForNativeColor(ColorID::Inactivecaption, ColorScheme::Light),
+        GetStandinForNativeColor(ColorID::Inactivecaptiontext,
+                                 ColorScheme::Light),
+        GetStandinForNativeColor(ColorID::Inactiveborder, ColorScheme::Light)};
+  }
+
+  // Our dark colors are always non-native.
+  result.mActiveDark = {*GenericDarkColor(ColorID::Activecaption),
+                        *GenericDarkColor(ColorID::Captiontext),
+                        *GenericDarkColor(ColorID::Activeborder)};
+  result.mInactiveDark = {*GenericDarkColor(ColorID::Inactivecaption),
+                          *GenericDarkColor(ColorID::Inactivecaptiontext),
+                          *GenericDarkColor(ColorID::Inactiveborder)};
+
+  // TODO(bug 1825241): Somehow get notified when this changes? Hopefully the
+  // sys color notification is enough.
+  WinRegistry::Key dwmKey(HKEY_CURRENT_USER,
+                          u"SOFTWARE\\Microsoft\\Windows\\DWM"_ns,
+                          WinRegistry::KeyMode::QueryValue);
+  if (NS_WARN_IF(!dwmKey)) {
+    return result;
+  }
+
+  // The order of the color components in the DWORD stored in the registry
+  // happens to be the same order as we store the components in nscolor
+  // so we can just assign directly here.
+  result.mAccent = dwmKey.GetValueAsDword(u"AccentColor"_ns);
+  result.mAccentText = GetAccentColorText(result.mAccent);
+
+  if (!result.mAccent) {
+    return result;
+  }
+
+  result.mAccentInactive = dwmKey.GetValueAsDword(u"AccentColorInactive"_ns);
+  result.mAccentInactiveText = GetAccentColorText(result.mAccentInactive);
+
+  // The ColorPrevalence value is set to 1 when the "Show color on title bar"
+  // setting in the Color section of Window's Personalization settings is
+  // turned on.
+  result.mUseAccent =
+      dwmKey.GetValueAsDword(u"ColorPrevalence"_ns).valueOr(0) == 1;
+  if (!result.mUseAccent) {
+    return result;
+  }
+
+  // TODO(emilio): Consider reading ColorizationColorBalance to compute a
+  // more correct border color, see [1]. Though for opaque accent colors this
+  // isn't needed.
+  //
+  // [1]:
+  // https://source.chromium.org/chromium/chromium/src/+/refs/heads/main:ui/color/win/accent_color_observer.cc;l=42;drc=9d4eb7ed25296abba8fd525a6bdd0fdbf4bcdd9f
+  result.mActiveDark.mBorder = result.mActiveLight.mBorder = *result.mAccent;
+  result.mInactiveDark.mBorder = result.mInactiveLight.mBorder =
+      result.mAccentInactive.valueOr(NS_RGB(57, 57, 57));
+  result.mActiveLight.mBg = result.mActiveDark.mBg = *result.mAccent;
+  result.mActiveLight.mFg = result.mActiveDark.mFg = *result.mAccentText;
+  if (result.mAccentInactive) {
+    result.mInactiveLight.mBg = result.mInactiveDark.mBg =
+        *result.mAccentInactive;
+    result.mInactiveLight.mFg = result.mInactiveDark.mFg =
+        *result.mAccentInactiveText;
+  } else {
+    // This is hand-picked to .8 to change the accent color a bit but not too
+    // much.
+    constexpr uint8_t kBgAlpha = 208;
+    const auto BlendWithAlpha = [](nscolor aBg, nscolor aFg,
+                                   uint8_t aAlpha) -> nscolor {
+      return NS_ComposeColors(
+          aBg, NS_RGBA(NS_GET_R(aFg), NS_GET_G(aFg), NS_GET_B(aFg), aAlpha));
+    };
+    result.mInactiveLight.mBg =
+        BlendWithAlpha(NS_RGB(255, 255, 255), *result.mAccent, kBgAlpha);
+    result.mInactiveDark.mBg =
+        BlendWithAlpha(NS_RGB(0, 0, 0), *result.mAccent, kBgAlpha);
+    result.mInactiveLight.mFg = result.mInactiveDark.mFg = *result.mAccentText;
+  }
+  return result;
+}
+
+void nsLookAndFeel::EnsureInit() {
+  if (mInitialized) {
+    return;
+  }
+  mInitialized = true;
+
+  mColorMenuHoverText =
+      ::GetColorFromTheme(eUXMenu, MENU_POPUPITEM, MPI_HOT, TMT_TEXTCOLOR);
+
+  // Fill out the sys color table.
+  for (int i = SYS_COLOR_MIN; i <= SYS_COLOR_MAX; ++i) {
+    mSysColorTable[i - SYS_COLOR_MIN] = [&] {
+      if (auto c = WindowsUIUtils::GetSystemColor(ColorScheme::Light, i)) {
+        return *c;
+      }
+      DWORD color = ::GetSysColor(i);
+      return COLOREF_2_NSRGB(color);
+    }();
+  }
+
+  mDarkHighlight =
+      WindowsUIUtils::GetSystemColor(ColorScheme::Dark, COLOR_HIGHLIGHT);
+  mDarkHighlightText =
+      WindowsUIUtils::GetSystemColor(ColorScheme::Dark, COLOR_HIGHLIGHTTEXT);
+
+  mTitlebarColors = ComputeTitlebarColors();
+
+  mColorAccent = [&] {
+    if (auto accent = WindowsUIUtils::GetAccentColor()) {
+      return *accent;
+    }
+    // Try the titlebar accent as a fallback.
+    if (mTitlebarColors.mAccent) {
+      return *mTitlebarColors.mAccent;
+    }
+    // Seems to be the default color (hardcoded because of bug 1065998)
+    return NS_RGB(0, 120, 215);
+  }();
+  mColorAccentText = GetAccentColorText(mColorAccent);
+
+  if (!mColorFilterWatcher) {
+    WinRegistry::Key key(
+        HKEY_CURRENT_USER, u"Software\\Microsoft\\ColorFiltering"_ns,
+        WinRegistry::KeyMode::QueryValue | WinRegistry::KeyMode::Notify);
+    if (key) {
+      mColorFilterWatcher = MakeUnique<WinRegistry::KeyWatcher>(
+          std::move(key), GetCurrentSerialEventTarget(), [this] {
+            MOZ_DIAGNOSTIC_ASSERT(NS_IsMainThread());
+            if (mCurrentColorFilter != SystemColorFilter()) {
+              LookAndFeel::NotifyChangedAllWindows(
+                  widget::ThemeChangeKind::MediaQueriesOnly);
+            }
+          });
+    }
+  }
+  mCurrentColorFilter = SystemColorFilter();
+
+  RecordTelemetry();
+}
diff --git a/widget/windows/nsLookAndFeel.h b/widget/windows/nsLookAndFeel.h
new file mode 100644
index 0000000000..d19aa91329
--- /dev/null
+++ b/widget/windows/nsLookAndFeel.h
@@ -0,0 +1,124 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsLookAndFeel
+#define __nsLookAndFeel
+
+#include <windows.h>
+
+#include "nsXPLookAndFeel.h"
+#include "gfxFont.h"
+
+/*
+ * Gesture System Metrics
+ */
+#ifndef SM_DIGITIZER
+#  define SM_DIGITIZER 94
+#  define TABLET_CONFIG_NONE 0x00000000
+#  define NID_INTEGRATED_TOUCH 0x00000001
+#  define NID_EXTERNAL_TOUCH 0x00000002
+#  define NID_INTEGRATED_PEN 0x00000004
+#  define NID_EXTERNAL_PEN 0x00000008
+#  define NID_MULTI_INPUT 0x00000040
+#  define NID_READY 0x00000080
+#endif
+
+/*
+ * Tablet mode detection
+ */
+#ifndef SM_SYSTEMDOCKED
+#  define SM_CONVERTIBLESLATEMODE 0x00002003
+#  define SM_SYSTEMDOCKED 0x00002004
+#endif
+
+/*
+ * Color constant inclusive bounds for GetSysColor
+ */
+#define SYS_COLOR_MIN 0
+#define SYS_COLOR_MAX 30
+#define SYS_COLOR_COUNT (SYS_COLOR_MAX - SYS_COLOR_MIN + 1)
+
+namespace mozilla::widget::WinRegistry {
+class KeyWatcher;
+}
+
+class nsLookAndFeel final : public nsXPLookAndFeel {
+ public:
+  nsLookAndFeel();
+  virtual ~nsLookAndFeel();
+
+  void NativeInit() final;
+  void RefreshImpl() override;
+  nsresult NativeGetInt(IntID, int32_t& aResult) override;
+  nsresult NativeGetFloat(FloatID, float& aResult) override;
+  nsresult NativeGetColor(ColorID, ColorScheme, nscolor& aResult) override;
+  bool NativeGetFont(FontID aID, nsString& aFontName,
+                     gfxFontStyle& aFontStyle) override;
+  char16_t GetPasswordCharacterImpl() override;
+
+ private:
+  struct TitlebarColors {
+    // NOTE: These are the DWM accent colors, which might not match the
+    // UISettings/UWP accent color in some cases, see bug 1796730.
+    mozilla::Maybe<nscolor> mAccent;
+    mozilla::Maybe<nscolor> mAccentText;
+    mozilla::Maybe<nscolor> mAccentInactive;
+    mozilla::Maybe<nscolor> mAccentInactiveText;
+
+    bool mUseAccent = false;
+
+    struct Set {
+      nscolor mBg = 0;
+      nscolor mFg = 0;
+      nscolor mBorder = 0;
+    };
+
+    Set mActiveLight;
+    Set mActiveDark;
+
+    Set mInactiveLight;
+    Set mInactiveDark;
+
+    const Set& Get(mozilla::ColorScheme aScheme, bool aActive) const {
+      if (aScheme == mozilla::ColorScheme::Dark) {
+        return aActive ? mActiveDark : mInactiveDark;
+      }
+      return aActive ? mActiveLight : mInactiveLight;
+    }
+  };
+
+  TitlebarColors ComputeTitlebarColors();
+
+  nscolor GetColorForSysColorIndex(int index);
+
+  LookAndFeelFont GetLookAndFeelFontInternal(const LOGFONTW& aLogFont,
+                                             bool aUseShellDlg);
+
+  uint32_t SystemColorFilter();
+
+  LookAndFeelFont GetLookAndFeelFont(LookAndFeel::FontID anID);
+
+  // Cached colors and flags indicating success in their retrieval.
+  mozilla::Maybe<nscolor> mColorMenuHoverText;
+
+  mozilla::Maybe<nscolor> mDarkHighlight;
+  mozilla::Maybe<nscolor> mDarkHighlightText;
+
+  TitlebarColors mTitlebarColors;
+
+  nscolor mColorAccent = 0;
+  nscolor mColorAccentText = 0;
+
+  nscolor mSysColorTable[SYS_COLOR_COUNT];
+
+  mozilla::UniquePtr<mozilla::widget::WinRegistry::KeyWatcher>
+      mColorFilterWatcher;
+  uint32_t mCurrentColorFilter = 0;
+
+  bool mInitialized = false;
+  void EnsureInit();
+};
+
+#endif
diff --git a/widget/windows/nsNativeDragSource.cpp b/widget/windows/nsNativeDragSource.cpp
new file mode 100644
index 0000000000..ca5459e9df
--- /dev/null
+++ b/widget/windows/nsNativeDragSource.cpp
@@ -0,0 +1,98 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsNativeDragSource.h"
+#include <stdio.h>
+#include "nsISupportsImpl.h"
+#include "nsString.h"
+#include "nsToolkit.h"
+#include "nsWidgetsCID.h"
+#include "nsIDragService.h"
+#include "nsServiceManagerUtils.h"
+#include "mozilla/dom/DataTransfer.h"
+
+/*
+ * class nsNativeDragSource
+ */
+nsNativeDragSource::nsNativeDragSource(
+    mozilla::dom::DataTransfer* aDataTransfer)
+    : m_cRef(0), m_hCursor(nullptr), mUserCancelled(false) {
+  mDataTransfer = aDataTransfer;
+}
+
+nsNativeDragSource::~nsNativeDragSource() {}
+
+STDMETHODIMP
+nsNativeDragSource::QueryInterface(REFIID riid, void** ppv) {
+  *ppv = nullptr;
+
+  if (IID_IUnknown == riid || IID_IDropSource == riid) *ppv = this;
+
+  if (nullptr != *ppv) {
+    ((LPUNKNOWN)*ppv)->AddRef();
+    return S_OK;
+  }
+
+  return E_NOINTERFACE;
+}
+
+STDMETHODIMP_(ULONG)
+nsNativeDragSource::AddRef(void) {
+  ++m_cRef;
+  NS_LOG_ADDREF(this, m_cRef, "nsNativeDragSource", sizeof(*this));
+  return m_cRef;
+}
+
+STDMETHODIMP_(ULONG)
+nsNativeDragSource::Release(void) {
+  --m_cRef;
+  NS_LOG_RELEASE(this, m_cRef, "nsNativeDragSource");
+  if (0 != m_cRef) return m_cRef;
+
+  delete this;
+  return 0;
+}
+
+STDMETHODIMP
+nsNativeDragSource::QueryContinueDrag(BOOL fEsc, DWORD grfKeyState) {
+  nsCOMPtr<nsIDragService> dragService =
+      do_GetService("@mozilla.org/widget/dragservice;1");
+  if (dragService) {
+    DWORD pos = ::GetMessagePos();
+    dragService->DragMoved(GET_X_LPARAM(pos), GET_Y_LPARAM(pos));
+  }
+
+  if (fEsc) {
+    mUserCancelled = true;
+    return DRAGDROP_S_CANCEL;
+  }
+
+  if (!(grfKeyState & MK_LBUTTON) || (grfKeyState & MK_RBUTTON))
+    return DRAGDROP_S_DROP;
+
+  return S_OK;
+}
+
+STDMETHODIMP
+nsNativeDragSource::GiveFeedback(DWORD dwEffect) {
+  // For drags involving tabs, we do some custom work with cursors.
+  if (mDataTransfer) {
+    nsAutoString cursor;
+    mDataTransfer->GetMozCursor(cursor);
+    if (cursor.EqualsLiteral("default")) {
+      m_hCursor = ::LoadCursor(0, IDC_ARROW);
+    } else {
+      m_hCursor = nullptr;
+    }
+  }
+
+  if (m_hCursor) {
+    ::SetCursor(m_hCursor);
+    return S_OK;
+  }
+
+  // Let the system choose which cursor to apply.
+  return DRAGDROP_S_USEDEFAULTCURSORS;
+}
diff --git a/widget/windows/nsNativeDragSource.h b/widget/windows/nsNativeDragSource.h
new file mode 100644
index 0000000000..a8e37b90a8
--- /dev/null
+++ b/widget/windows/nsNativeDragSource.h
@@ -0,0 +1,68 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef _nsNativeDragSource_h_
+#define _nsNativeDragSource_h_
+
+#include "nscore.h"
+#include <ole2.h>
+#include <oleidl.h>
+#include "mozilla/Attributes.h"
+#include "mozilla/RefPtr.h"
+
+namespace mozilla {
+namespace dom {
+class DataTransfer;
+}  // namespace dom
+}  // namespace mozilla
+
+// class nsIDragSource;
+
+/*
+ * nsNativeDragSource implements the IDropSource interface and gets
+ * most of its behavior from the associated adapter (m_dragDrop).
+ */
+class nsNativeDragSource final : public IDropSource {
+ public:
+  // construct an nsNativeDragSource referencing adapter
+  // nsNativeDragSource(nsIDragSource * adapter);
+  explicit nsNativeDragSource(mozilla::dom::DataTransfer* aDataTransfer);
+  ~nsNativeDragSource();
+
+  // IUnknown methods - see iunknown.h for documentation
+
+  STDMETHODIMP QueryInterface(REFIID, void**);
+  STDMETHODIMP_(ULONG) AddRef();
+  STDMETHODIMP_(ULONG) Release();
+
+  // IDropSource methods - see idropsrc.h for documentation
+
+  // Return DRAGDROP_S_USEDEFAULTCURSORS if this object lets OLE provide
+  // default cursors, otherwise return NOERROR. This method gets called in
+  // response to changes that the target makes to dEffect (DragEnter,
+  // DragOver).
+  STDMETHODIMP GiveFeedback(DWORD dEffect);
+
+  // This method gets called if there is any change in the mouse or key
+  // state.  Return DRAGDROP_S_CANCEL to stop the drag, DRAGDROP_S_DROP
+  // to execute the drop, otherwise NOERROR.
+  STDMETHODIMP QueryContinueDrag(BOOL fESC, DWORD grfKeyState);
+
+  bool UserCancelled() { return mUserCancelled; }
+
+ protected:
+  // Reference count
+  ULONG m_cRef;
+
+  // Data object, hold information about cursor state
+  RefPtr<mozilla::dom::DataTransfer> mDataTransfer;
+
+  // Custom drag cursor
+  HCURSOR m_hCursor;
+
+  // true if the user cancelled the drag by pressing escape
+  bool mUserCancelled;
+};
+
+#endif  // _nsNativeDragSource_h_
diff --git a/widget/windows/nsNativeDragTarget.cpp b/widget/windows/nsNativeDragTarget.cpp
new file mode 100644
index 0000000000..b615a3e4bc
--- /dev/null
+++ b/widget/windows/nsNativeDragTarget.cpp
@@ -0,0 +1,472 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <stdio.h>
+#include "nsIDragService.h"
+#include "nsWidgetsCID.h"
+#include "nsNativeDragTarget.h"
+#include "nsDragService.h"
+#include "nsINode.h"
+#include "nsCOMPtr.h"
+
+#include "nsIWidget.h"
+#include "nsWindow.h"
+#include "nsClipboard.h"
+#include "KeyboardLayout.h"
+
+#include "mozilla/MouseEvents.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+// This is cached for Leave notification
+static POINTL gDragLastPoint;
+
+bool nsNativeDragTarget::gDragImageChanged = false;
+
+/*
+ * class nsNativeDragTarget
+ */
+nsNativeDragTarget::nsNativeDragTarget(nsIWidget* aWidget)
+    : m_cRef(0),
+      mEffectsAllowed(DROPEFFECT_MOVE | DROPEFFECT_COPY | DROPEFFECT_LINK),
+      mEffectsPreferred(DROPEFFECT_NONE),
+      mTookOwnRef(false),
+      mWidget(aWidget),
+      mDropTargetHelper(nullptr) {
+  mHWnd = (HWND)mWidget->GetNativeData(NS_NATIVE_WINDOW);
+
+  mDragService = do_GetService("@mozilla.org/widget/dragservice;1");
+}
+
+nsNativeDragTarget::~nsNativeDragTarget() {
+  if (mDropTargetHelper) {
+    mDropTargetHelper->Release();
+    mDropTargetHelper = nullptr;
+  }
+}
+
+// IUnknown methods - see iunknown.h for documentation
+STDMETHODIMP
+nsNativeDragTarget::QueryInterface(REFIID riid, void** ppv) {
+  *ppv = nullptr;
+
+  if (IID_IUnknown == riid || IID_IDropTarget == riid) *ppv = this;
+
+  if (nullptr != *ppv) {
+    ((LPUNKNOWN)*ppv)->AddRef();
+    return S_OK;
+  }
+
+  return E_NOINTERFACE;
+}
+
+STDMETHODIMP_(ULONG)
+nsNativeDragTarget::AddRef(void) {
+  ++m_cRef;
+  NS_LOG_ADDREF(this, m_cRef, "nsNativeDragTarget", sizeof(*this));
+  return m_cRef;
+}
+
+STDMETHODIMP_(ULONG) nsNativeDragTarget::Release(void) {
+  --m_cRef;
+  NS_LOG_RELEASE(this, m_cRef, "nsNativeDragTarget");
+  if (0 != m_cRef) return m_cRef;
+
+  delete this;
+  return 0;
+}
+
+void nsNativeDragTarget::GetGeckoDragAction(DWORD grfKeyState,
+                                            LPDWORD pdwEffect,
+                                            uint32_t* aGeckoAction) {
+  // If a window is disabled or a modal window is on top of it
+  // (which implies it is disabled), then we should not allow dropping.
+  if (!mWidget->IsEnabled()) {
+    *pdwEffect = DROPEFFECT_NONE;
+    *aGeckoAction = nsIDragService::DRAGDROP_ACTION_NONE;
+    return;
+  }
+
+  // If the user explicitly uses a modifier key, they want the associated action
+  // Shift + Control -> LINK, Shift -> MOVE, Ctrl -> COPY
+  DWORD desiredEffect = DROPEFFECT_NONE;
+  if ((grfKeyState & MK_CONTROL) && (grfKeyState & MK_SHIFT)) {
+    desiredEffect = DROPEFFECT_LINK;
+  } else if (grfKeyState & MK_SHIFT) {
+    desiredEffect = DROPEFFECT_MOVE;
+  } else if (grfKeyState & MK_CONTROL) {
+    desiredEffect = DROPEFFECT_COPY;
+  }
+
+  // Determine the desired effect from what is allowed and preferred.
+  if (!(desiredEffect &= mEffectsAllowed)) {
+    // No modifier key effect is set which is also allowed, check
+    // the preference of the data.
+    desiredEffect = mEffectsPreferred & mEffectsAllowed;
+    if (!desiredEffect) {
+      // No preference is set, so just fall back to the allowed effect itself
+      desiredEffect = mEffectsAllowed;
+    }
+  }
+
+  // Otherwise we should specify the first available effect
+  // from MOVE, COPY, or LINK.
+  if (desiredEffect & DROPEFFECT_MOVE) {
+    *pdwEffect = DROPEFFECT_MOVE;
+    *aGeckoAction = nsIDragService::DRAGDROP_ACTION_MOVE;
+  } else if (desiredEffect & DROPEFFECT_COPY) {
+    *pdwEffect = DROPEFFECT_COPY;
+    *aGeckoAction = nsIDragService::DRAGDROP_ACTION_COPY;
+  } else if (desiredEffect & DROPEFFECT_LINK) {
+    *pdwEffect = DROPEFFECT_LINK;
+    *aGeckoAction = nsIDragService::DRAGDROP_ACTION_LINK;
+  } else {
+    *pdwEffect = DROPEFFECT_NONE;
+    *aGeckoAction = nsIDragService::DRAGDROP_ACTION_NONE;
+  }
+}
+
+inline bool IsKeyDown(char key) { return GetKeyState(key) < 0; }
+
+void nsNativeDragTarget::DispatchDragDropEvent(EventMessage aEventMessage,
+                                               const POINTL& aPT) {
+  WidgetDragEvent event(true, aEventMessage, mWidget);
+
+  nsWindow* win = static_cast<nsWindow*>(mWidget);
+  win->InitEvent(event);
+  POINT cpos;
+
+  cpos.x = aPT.x;
+  cpos.y = aPT.y;
+
+  if (mHWnd != nullptr) {
+    ::ScreenToClient(mHWnd, &cpos);
+    event.mRefPoint = LayoutDeviceIntPoint(cpos.x, cpos.y);
+  } else {
+    event.mRefPoint = LayoutDeviceIntPoint(0, 0);
+  }
+
+  ModifierKeyState modifierKeyState;
+  modifierKeyState.InitInputEvent(event);
+
+  event.mInputSource =
+      static_cast<nsBaseDragService*>(mDragService.get())->GetInputSource();
+
+  mWidget->DispatchInputEvent(&event);
+}
+
+void nsNativeDragTarget::ProcessDrag(EventMessage aEventMessage,
+                                     DWORD grfKeyState, POINTL ptl,
+                                     DWORD* pdwEffect) {
+  // Before dispatching the event make sure we have the correct drop action set
+  uint32_t geckoAction;
+  GetGeckoDragAction(grfKeyState, pdwEffect, &geckoAction);
+
+  // Set the current action into the Gecko specific type
+  nsCOMPtr<nsIDragSession> currSession;
+  mDragService->GetCurrentSession(getter_AddRefs(currSession));
+  if (!currSession) {
+    return;
+  }
+
+  currSession->SetDragAction(geckoAction);
+
+  // Dispatch the event into Gecko
+  DispatchDragDropEvent(aEventMessage, ptl);
+
+  // If TakeChildProcessDragAction returns something other than
+  // DRAGDROP_ACTION_UNINITIALIZED, it means that the last event was sent
+  // to the child process and this event is also being sent to the child
+  // process. In this case, use the last event's action instead.
+  nsDragService* dragService = static_cast<nsDragService*>(mDragService.get());
+  currSession->GetDragAction(&geckoAction);
+
+  int32_t childDragAction = dragService->TakeChildProcessDragAction();
+  if (childDragAction != nsIDragService::DRAGDROP_ACTION_UNINITIALIZED) {
+    geckoAction = childDragAction;
+  }
+
+  if (nsIDragService::DRAGDROP_ACTION_LINK & geckoAction) {
+    *pdwEffect = DROPEFFECT_LINK;
+  } else if (nsIDragService::DRAGDROP_ACTION_COPY & geckoAction) {
+    *pdwEffect = DROPEFFECT_COPY;
+  } else if (nsIDragService::DRAGDROP_ACTION_MOVE & geckoAction) {
+    *pdwEffect = DROPEFFECT_MOVE;
+  } else {
+    *pdwEffect = DROPEFFECT_NONE;
+  }
+
+  if (aEventMessage != eDrop) {
+    // Get the cached drag effect from the drag service, the data member should
+    // have been set by whoever handled the WidgetGUIEvent or nsIDOMEvent on
+    // drags.
+    bool canDrop;
+    currSession->GetCanDrop(&canDrop);
+    if (!canDrop) {
+      *pdwEffect = DROPEFFECT_NONE;
+    }
+  }
+
+  // Clear the cached value
+  currSession->SetCanDrop(false);
+}
+
+// IDropTarget methods
+STDMETHODIMP
+nsNativeDragTarget::DragEnter(LPDATAOBJECT pIDataSource, DWORD grfKeyState,
+                              POINTL ptl, DWORD* pdwEffect) {
+  if (!mDragService) {
+    return E_FAIL;
+  }
+
+  mEffectsAllowed = *pdwEffect;
+  AddLinkSupportIfCanBeGenerated(pIDataSource);
+
+  // Drag and drop image helper
+  if (GetDropTargetHelper()) {
+    // We get a lot of crashes (often uncaught by our handler) later on during
+    // DragOver calls, see bug 1465513. It looks like this might be because
+    // we're not cleaning up previous drags fully and now released resources get
+    // used. Calling IDropTargetHelper::DragLeave before DragEnter seems to fix
+    // this for at least one reproduction of this crash.
+    GetDropTargetHelper()->DragLeave();
+    POINT pt = {ptl.x, ptl.y};
+    GetDropTargetHelper()->DragEnter(mHWnd, pIDataSource, &pt, *pdwEffect);
+  }
+
+  // save a ref to this, in case the window is destroyed underneath us
+  NS_ASSERTION(!mTookOwnRef, "own ref already taken!");
+  this->AddRef();
+  mTookOwnRef = true;
+
+  // tell the drag service about this drag (it may have come from an
+  // outside app).
+  mDragService->StartDragSession();
+
+  void* tempOutData = nullptr;
+  uint32_t tempDataLen = 0;
+  nsresult loadResult = nsClipboard::GetNativeDataOffClipboard(
+      pIDataSource, 0, ::RegisterClipboardFormat(CFSTR_PREFERREDDROPEFFECT),
+      nullptr, &tempOutData, &tempDataLen);
+  if (NS_SUCCEEDED(loadResult) && tempOutData) {
+    mEffectsPreferred = *((DWORD*)tempOutData);
+    free(tempOutData);
+  } else {
+    // We have no preference if we can't obtain it
+    mEffectsPreferred = DROPEFFECT_NONE;
+  }
+
+  // Set the native data object into drag service
+  //
+  // This cast is ok because in the constructor we created a
+  // the actual implementation we wanted, so we know this is
+  // a nsDragService. It should be a private interface, though.
+  nsDragService* winDragService =
+      static_cast<nsDragService*>(mDragService.get());
+  winDragService->SetIDataObject(pIDataSource);
+
+  // Now process the native drag state and then dispatch the event
+  ProcessDrag(eDragEnter, grfKeyState, ptl, pdwEffect);
+
+  return S_OK;
+}
+
+void nsNativeDragTarget::AddLinkSupportIfCanBeGenerated(
+    LPDATAOBJECT aIDataSource) {
+  // If we don't have a link effect, but we can generate one, fix the
+  // drop effect to include it.
+  if (!(mEffectsAllowed & DROPEFFECT_LINK) && aIDataSource) {
+    if (S_OK == ::OleQueryLinkFromData(aIDataSource)) {
+      mEffectsAllowed |= DROPEFFECT_LINK;
+    }
+  }
+}
+
+STDMETHODIMP
+nsNativeDragTarget::DragOver(DWORD grfKeyState, POINTL ptl, LPDWORD pdwEffect) {
+  if (!mDragService) {
+    return E_FAIL;
+  }
+
+  bool dragImageChanged = gDragImageChanged;
+  gDragImageChanged = false;
+
+  // If a LINK effect could be generated previously from a DragEnter(),
+  // then we should include it as an allowed effect.
+  mEffectsAllowed = (*pdwEffect) | (mEffectsAllowed & DROPEFFECT_LINK);
+
+  nsCOMPtr<nsIDragSession> currentDragSession;
+  mDragService->GetCurrentSession(getter_AddRefs(currentDragSession));
+  if (!currentDragSession) {
+    return S_OK;  // Drag was canceled.
+  }
+
+  // without the AddRef() |this| can get destroyed in an event handler
+  this->AddRef();
+
+  // Drag and drop image helper
+  if (GetDropTargetHelper()) {
+    if (dragImageChanged) {
+      // See comment in nsNativeDragTarget::DragEnter.
+      GetDropTargetHelper()->DragLeave();
+      // The drop helper only updates the image during DragEnter, so emulate
+      // a DragEnter if the image was changed.
+      POINT pt = {ptl.x, ptl.y};
+      nsDragService* dragService =
+          static_cast<nsDragService*>(mDragService.get());
+      GetDropTargetHelper()->DragEnter(mHWnd, dragService->GetDataObject(), &pt,
+                                       *pdwEffect);
+    }
+    POINT pt = {ptl.x, ptl.y};
+    GetDropTargetHelper()->DragOver(&pt, *pdwEffect);
+  }
+
+  ModifierKeyState modifierKeyState;
+  nsCOMPtr<nsIDragService> dragService = mDragService;
+  dragService->FireDragEventAtSource(eDrag, modifierKeyState.GetModifiers());
+  // Now process the native drag state and then dispatch the event
+  ProcessDrag(eDragOver, grfKeyState, ptl, pdwEffect);
+
+  this->Release();
+
+  return S_OK;
+}
+
+STDMETHODIMP
+nsNativeDragTarget::DragLeave() {
+  if (!mDragService) {
+    return E_FAIL;
+  }
+
+  // Drag and drop image helper
+  if (GetDropTargetHelper()) {
+    GetDropTargetHelper()->DragLeave();
+  }
+
+  // dispatch the event into Gecko
+  DispatchDragDropEvent(eDragExit, gDragLastPoint);
+
+  nsCOMPtr<nsIDragSession> currentDragSession;
+  mDragService->GetCurrentSession(getter_AddRefs(currentDragSession));
+
+  if (currentDragSession) {
+    nsCOMPtr<nsINode> sourceNode;
+    currentDragSession->GetSourceNode(getter_AddRefs(sourceNode));
+
+    if (!sourceNode) {
+      // We're leaving a window while doing a drag that was
+      // initiated in a different app. End the drag session, since
+      // we're done with it for now (until the user drags back into
+      // mozilla).
+      ModifierKeyState modifierKeyState;
+      nsCOMPtr<nsIDragService> dragService = mDragService;
+      dragService->EndDragSession(false, modifierKeyState.GetModifiers());
+    }
+  }
+
+  // release the ref that was taken in DragEnter
+  NS_ASSERTION(mTookOwnRef, "want to release own ref, but not taken!");
+  if (mTookOwnRef) {
+    this->Release();
+    mTookOwnRef = false;
+  }
+
+  return S_OK;
+}
+
+void nsNativeDragTarget::DragCancel() {
+  // Cancel the drag session if we did DragEnter.
+  if (mTookOwnRef) {
+    if (GetDropTargetHelper()) {
+      GetDropTargetHelper()->DragLeave();
+    }
+    if (mDragService) {
+      ModifierKeyState modifierKeyState;
+      nsCOMPtr<nsIDragService> dragService = mDragService;
+      dragService->EndDragSession(false, modifierKeyState.GetModifiers());
+    }
+    this->Release();  // matching the AddRef in DragEnter
+    mTookOwnRef = false;
+  }
+}
+
+STDMETHODIMP
+nsNativeDragTarget::Drop(LPDATAOBJECT pData, DWORD grfKeyState, POINTL aPT,
+                         LPDWORD pdwEffect) {
+  if (!mDragService) {
+    return E_FAIL;
+  }
+
+  mEffectsAllowed = *pdwEffect;
+  AddLinkSupportIfCanBeGenerated(pData);
+
+  // Drag and drop image helper
+  if (GetDropTargetHelper()) {
+    POINT pt = {aPT.x, aPT.y};
+    GetDropTargetHelper()->Drop(pData, &pt, *pdwEffect);
+  }
+
+  // Set the native data object into the drag service
+  //
+  // This cast is ok because in the constructor we created a
+  // the actual implementation we wanted, so we know this is
+  // a nsDragService (but it should still be a private interface)
+  nsDragService* winDragService =
+      static_cast<nsDragService*>(mDragService.get());
+  winDragService->SetIDataObject(pData);
+
+  // NOTE: ProcessDrag spins the event loop which may destroy arbitrary objects.
+  // We use strong refs to prevent it from destroying these:
+  RefPtr<nsNativeDragTarget> kungFuDeathGrip = this;
+  nsCOMPtr<nsIDragService> serv = mDragService;
+
+  // Now process the native drag state and then dispatch the event
+  ProcessDrag(eDrop, grfKeyState, aPT, pdwEffect);
+
+  nsCOMPtr<nsIDragSession> currentDragSession;
+  serv->GetCurrentSession(getter_AddRefs(currentDragSession));
+  if (!currentDragSession) {
+    return S_OK;  // DragCancel() was called.
+  }
+
+  // Let the win drag service know whether this session experienced
+  // a drop event within the application. Drop will not oocur if the
+  // drop landed outside the app. (used in tab tear off, bug 455884)
+  winDragService->SetDroppedLocal();
+
+  // tell the drag service we're done with the session
+  // Use GetMessagePos to get the position of the mouse at the last message
+  // seen by the event loop. (Bug 489729)
+  DWORD pos = ::GetMessagePos();
+  POINT cpos;
+  cpos.x = GET_X_LPARAM(pos);
+  cpos.y = GET_Y_LPARAM(pos);
+  winDragService->SetDragEndPoint(nsIntPoint(cpos.x, cpos.y));
+  ModifierKeyState modifierKeyState;
+  serv->EndDragSession(true, modifierKeyState.GetModifiers());
+
+  // release the ref that was taken in DragEnter
+  NS_ASSERTION(mTookOwnRef, "want to release own ref, but not taken!");
+  if (mTookOwnRef) {
+    this->Release();
+    mTookOwnRef = false;
+  }
+
+  return S_OK;
+}
+
+/**
+ * By lazy loading mDropTargetHelper we save 50-70ms of startup time
+ * which is ~5% of startup time.
+ */
+IDropTargetHelper* nsNativeDragTarget::GetDropTargetHelper() {
+  if (!mDropTargetHelper) {
+    CoCreateInstance(CLSID_DragDropHelper, nullptr, CLSCTX_INPROC_SERVER,
+                     IID_IDropTargetHelper, (LPVOID*)&mDropTargetHelper);
+  }
+
+  return mDropTargetHelper;
+}
diff --git a/widget/windows/nsNativeDragTarget.h b/widget/windows/nsNativeDragTarget.h
new file mode 100644
index 0000000000..82edc7aae7
--- /dev/null
+++ b/widget/windows/nsNativeDragTarget.h
@@ -0,0 +1,103 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef _nsNativeDragTarget_h_
+#define _nsNativeDragTarget_h_
+
+#include "nsCOMPtr.h"
+#include <ole2.h>
+#include <shlobj.h>
+
+#ifndef IDropTargetHelper
+#  include <shobjidl.h>  // Vista drag image interfaces
+#  undef LogSeverity     // SetupAPI.h #defines this as DWORD
+#endif
+
+#include "mozilla/Attributes.h"
+#include "mozilla/EventForwards.h"
+
+class nsIDragService;
+class nsIWidget;
+
+/*
+ * nsNativeDragTarget implements the IDropTarget interface and gets most of its
+ * behavior from the associated adapter (m_dragDrop).
+ */
+
+class nsNativeDragTarget final : public IDropTarget {
+ public:
+  explicit nsNativeDragTarget(nsIWidget* aWidget);
+  ~nsNativeDragTarget();
+
+  // IUnknown members - see iunknown.h for documentation
+  STDMETHODIMP QueryInterface(REFIID, void**);
+  STDMETHODIMP_(ULONG) AddRef();
+  STDMETHODIMP_(ULONG) Release();
+
+  // IDataTarget members
+
+  // Set pEffect based on whether this object can support a drop based on
+  // the data available from pSource, the key and mouse states specified
+  // in grfKeyState, and the coordinates specified by point. This is
+  // called by OLE when a drag enters this object's window (as registered
+  // by Initialize).
+  STDMETHODIMP DragEnter(LPDATAOBJECT pSource, DWORD grfKeyState, POINTL point,
+                         DWORD* pEffect);
+
+  // Similar to DragEnter except it is called frequently while the drag
+  // is over this object's window.
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY STDMETHODIMP DragOver(DWORD grfKeyState,
+                                                    POINTL point,
+                                                    DWORD* pEffect);
+
+  // Release the drag-drop source and put internal state back to the point
+  // before the call to DragEnter. This is called when the drag leaves
+  // without a drop occurring.
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY STDMETHODIMP DragLeave();
+
+  // If point is within our region of interest and pSource's data supports
+  // one of our formats, get the data and set pEffect according to
+  // grfKeyState (DROPEFFECT_MOVE if the control key was not pressed,
+  // DROPEFFECT_COPY if the control key was pressed). Otherwise return
+  // E_FAIL.
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY STDMETHODIMP Drop(LPDATAOBJECT pSource,
+                                                DWORD grfKeyState, POINTL point,
+                                                DWORD* pEffect);
+  /**
+   * Cancel the current drag session, if any.
+   */
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY void DragCancel();
+
+  static void DragImageChanged() { gDragImageChanged = true; }
+
+ protected:
+  void GetGeckoDragAction(DWORD grfKeyState, LPDWORD pdwEffect,
+                          uint32_t* aGeckoAction);
+  void ProcessDrag(mozilla::EventMessage aEventMessage, DWORD grfKeyState,
+                   POINTL pt, DWORD* pdwEffect);
+  void DispatchDragDropEvent(mozilla::EventMessage aEventMessage,
+                             const POINTL& aPT);
+  void AddLinkSupportIfCanBeGenerated(LPDATAOBJECT aIDataSource);
+
+  // Native Stuff
+  ULONG m_cRef;  // reference count
+  HWND mHWnd;
+  DWORD mEffectsAllowed;
+  DWORD mEffectsPreferred;
+  bool mTookOwnRef;
+
+  // Gecko Stuff
+  nsIWidget* mWidget;
+  nsCOMPtr<nsIDragService> mDragService;
+  // Drag target helper
+  IDropTargetHelper* GetDropTargetHelper();
+
+ private:
+  // Drag target helper
+  IDropTargetHelper* mDropTargetHelper;
+
+  static bool gDragImageChanged;
+};
+
+#endif  // _nsNativeDragTarget_h_
diff --git a/widget/windows/nsNativeThemeWin.cpp b/widget/windows/nsNativeThemeWin.cpp
new file mode 100644
index 0000000000..04883a833f
--- /dev/null
+++ b/widget/windows/nsNativeThemeWin.cpp
@@ -0,0 +1,1975 @@
+/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsNativeThemeWin.h"
+
+#include <algorithm>
+#include <malloc.h>
+
+#include "gfxContext.h"
+#include "gfxPlatform.h"
+#include "gfxWindowsNativeDrawing.h"
+#include "gfxWindowsPlatform.h"
+#include "gfxWindowsSurface.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/gfx/Types.h"  // for Color::FromABGR
+#include "mozilla/Logging.h"
+#include "mozilla/RelativeLuminanceUtils.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/dom/XULButtonElement.h"
+#include "nsColor.h"
+#include "nsComboboxControlFrame.h"
+#include "nsDeviceContext.h"
+#include "nsGkAtoms.h"
+#include "nsIContent.h"
+#include "nsIContentInlines.h"
+#include "nsIFrame.h"
+#include "nsLayoutUtils.h"
+#include "nsLookAndFeel.h"
+#include "nsNameSpaceManager.h"
+#include "Theme.h"
+#include "nsPresContext.h"
+#include "nsRect.h"
+#include "nsSize.h"
+#include "nsStyleConsts.h"
+#include "nsTransform2D.h"
+#include "nsWindow.h"
+#include "prinrval.h"
+#include "WinUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using namespace mozilla::widget;
+
+using ElementState = dom::ElementState;
+
+extern mozilla::LazyLogModule gWindowsLog;
+
+namespace mozilla::widget {
+
+nsNativeThemeWin::nsNativeThemeWin()
+    : Theme(ScrollbarStyle()),
+      mProgressDeterminateTimeStamp(TimeStamp::Now()),
+      mProgressIndeterminateTimeStamp(TimeStamp::Now()),
+      mBorderCacheValid(),
+      mMinimumWidgetSizeCacheValid(),
+      mGutterSizeCacheValid(false) {}
+
+nsNativeThemeWin::~nsNativeThemeWin() { nsUXThemeData::Invalidate(); }
+
+bool nsNativeThemeWin::IsWidgetAlwaysNonNative(nsIFrame* aFrame,
+                                               StyleAppearance aAppearance) {
+  return Theme::IsWidgetAlwaysNonNative(aFrame, aAppearance) ||
+         aAppearance == StyleAppearance::Checkbox ||
+         aAppearance == StyleAppearance::Radio ||
+         aAppearance == StyleAppearance::MozMenulistArrowButton ||
+         aAppearance == StyleAppearance::SpinnerUpbutton ||
+         aAppearance == StyleAppearance::SpinnerDownbutton;
+}
+
+auto nsNativeThemeWin::IsWidgetNonNative(nsIFrame* aFrame,
+                                         StyleAppearance aAppearance)
+    -> NonNative {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return NonNative::Always;
+  }
+
+  // We only know how to draw light widgets, so we defer to the non-native
+  // theme when appropriate.
+  if (Theme::ThemeSupportsWidget(aFrame->PresContext(), aFrame, aAppearance) &&
+      LookAndFeel::ColorSchemeForFrame(aFrame) ==
+          LookAndFeel::ColorScheme::Dark) {
+    return NonNative::BecauseColorMismatch;
+  }
+  return NonNative::No;
+}
+
+static MARGINS GetCheckboxMargins(HANDLE theme, HDC hdc) {
+  MARGINS checkboxContent = {0};
+  GetThemeMargins(theme, hdc, MENU_POPUPCHECK, MCB_NORMAL, TMT_CONTENTMARGINS,
+                  nullptr, &checkboxContent);
+  return checkboxContent;
+}
+
+static SIZE GetCheckboxBGSize(HANDLE theme, HDC hdc) {
+  SIZE checkboxSize;
+  GetThemePartSize(theme, hdc, MENU_POPUPCHECK, MC_CHECKMARKNORMAL, nullptr,
+                   TS_TRUE, &checkboxSize);
+
+  MARGINS checkboxMargins = GetCheckboxMargins(theme, hdc);
+
+  int leftMargin = checkboxMargins.cxLeftWidth;
+  int rightMargin = checkboxMargins.cxRightWidth;
+  int topMargin = checkboxMargins.cyTopHeight;
+  int bottomMargin = checkboxMargins.cyBottomHeight;
+
+  int width = leftMargin + checkboxSize.cx + rightMargin;
+  int height = topMargin + checkboxSize.cy + bottomMargin;
+  SIZE ret;
+  ret.cx = width;
+  ret.cy = height;
+  return ret;
+}
+
+static SIZE GetCheckboxBGBounds(HANDLE theme, HDC hdc) {
+  MARGINS checkboxBGSizing = {0};
+  MARGINS checkboxBGContent = {0};
+  GetThemeMargins(theme, hdc, MENU_POPUPCHECKBACKGROUND, MCB_NORMAL,
+                  TMT_SIZINGMARGINS, nullptr, &checkboxBGSizing);
+  GetThemeMargins(theme, hdc, MENU_POPUPCHECKBACKGROUND, MCB_NORMAL,
+                  TMT_CONTENTMARGINS, nullptr, &checkboxBGContent);
+
+#define posdx(d) ((d) > 0 ? d : 0)
+
+  int dx =
+      posdx(checkboxBGContent.cxRightWidth - checkboxBGSizing.cxRightWidth) +
+      posdx(checkboxBGContent.cxLeftWidth - checkboxBGSizing.cxLeftWidth);
+  int dy =
+      posdx(checkboxBGContent.cyTopHeight - checkboxBGSizing.cyTopHeight) +
+      posdx(checkboxBGContent.cyBottomHeight - checkboxBGSizing.cyBottomHeight);
+
+#undef posdx
+
+  SIZE ret(GetCheckboxBGSize(theme, hdc));
+  ret.cx += dx;
+  ret.cy += dy;
+  return ret;
+}
+
+static SIZE GetGutterSize(HANDLE theme, HDC hdc) {
+  SIZE gutterSize;
+  GetThemePartSize(theme, hdc, MENU_POPUPGUTTER, 0, nullptr, TS_TRUE,
+                   &gutterSize);
+
+  SIZE checkboxBGSize(GetCheckboxBGBounds(theme, hdc));
+
+  SIZE itemSize;
+  GetThemePartSize(theme, hdc, MENU_POPUPITEM, MPI_NORMAL, nullptr, TS_TRUE,
+                   &itemSize);
+
+  // Figure out how big the menuitem's icon will be (if present) at current DPI
+  // Needs the system scale for consistency with Windows Theme API.
+  double scaleFactor = WinUtils::SystemScaleFactor();
+  int iconDevicePixels = NSToIntRound(16 * scaleFactor);
+  SIZE iconSize = {iconDevicePixels, iconDevicePixels};
+  // Not really sure what margins should be used here, but this seems to work in
+  // practice...
+  MARGINS margins = {0};
+  GetThemeMargins(theme, hdc, MENU_POPUPCHECKBACKGROUND, MCB_NORMAL,
+                  TMT_CONTENTMARGINS, nullptr, &margins);
+  iconSize.cx += margins.cxLeftWidth + margins.cxRightWidth;
+  iconSize.cy += margins.cyTopHeight + margins.cyBottomHeight;
+
+  int width = std::max(
+      itemSize.cx, std::max(iconSize.cx, checkboxBGSize.cx) + gutterSize.cx);
+  int height = std::max(itemSize.cy, std::max(iconSize.cy, checkboxBGSize.cy));
+
+  SIZE ret;
+  ret.cx = width;
+  ret.cy = height;
+  return ret;
+}
+
+SIZE nsNativeThemeWin::GetCachedGutterSize(HANDLE theme) {
+  if (mGutterSizeCacheValid) {
+    return mGutterSizeCache;
+  }
+
+  mGutterSizeCache = GetGutterSize(theme, nullptr);
+  mGutterSizeCacheValid = true;
+
+  return mGutterSizeCache;
+}
+
+/*
+ * Notes on progress track and meter part constants:
+ * xp and up:
+ * PP_BAR(_VERT)            - base progress track
+ * PP_TRANSPARENTBAR(_VERT) - transparent progress track. this only works if
+ *                            the underlying surface supports alpha. otherwise
+ *                            theme lib's DrawThemeBackground falls back on
+ *                            opaque PP_BAR. we currently don't use this.
+ * PP_CHUNK(_VERT)          - xp progress meter. this does not draw an xp style
+ *                            progress w/chunks, it draws fill using the chunk
+ *                            graphic.
+ * vista and up:
+ * PP_FILL(_VERT)           - progress meter. these have four states/colors.
+ * PP_PULSEOVERLAY(_VERT)   - white reflection - an overlay, not sure what this
+ *                            is used for.
+ * PP_MOVEOVERLAY(_VERT)    - green pulse - the pulse effect overlay on
+ *                            determined progress bars. we also use this for
+ *                            indeterminate chunk.
+ *
+ * Notes on state constants:
+ * PBBS_NORMAL               - green progress
+ * PBBVS_PARTIAL/PBFVS_ERROR - red error progress
+ * PBFS_PAUSED               - yellow paused progress
+ *
+ * There is no common controls style indeterminate part on vista and up.
+ */
+
+/*
+ * Progress bar related constants. These values are found by experimenting and
+ * comparing against native widgets used by the system. They are very unlikely
+ * exact but try to not be too wrong.
+ */
+// The amount of time we animate progress meters parts across the frame.
+static const double kProgressDeterminateTimeSpan = 3.0;
+static const double kProgressIndeterminateTimeSpan = 5.0;
+// The width of the overlay used to animate the horizontal progress bar (Vista
+// and later).
+static const int32_t kProgressHorizontalOverlaySize = 120;
+// The height of the overlay used to animate the vertical progress bar (Vista
+// and later).
+static const int32_t kProgressVerticalOverlaySize = 45;
+// The height of the overlay used for the vertical indeterminate progress bar
+// (Vista and later).
+static const int32_t kProgressVerticalIndeterminateOverlaySize = 60;
+// The width of the overlay used to animate the indeterminate progress bar
+// (Windows Classic).
+static const int32_t kProgressClassicOverlaySize = 40;
+
+/*
+ * GetProgressOverlayStyle - returns the proper overlay part for themed
+ * progress bars based on os and orientation.
+ */
+static int32_t GetProgressOverlayStyle(bool aIsVertical) {
+  return aIsVertical ? PP_MOVEOVERLAYVERT : PP_MOVEOVERLAY;
+}
+
+/*
+ * GetProgressOverlaySize - returns the minimum width or height for themed
+ * progress bar overlays. This includes the width of indeterminate chunks
+ * and vista pulse overlays.
+ */
+static int32_t GetProgressOverlaySize(bool aIsVertical, bool aIsIndeterminate) {
+  if (aIsVertical) {
+    return aIsIndeterminate ? kProgressVerticalIndeterminateOverlaySize
+                            : kProgressVerticalOverlaySize;
+  }
+  return kProgressHorizontalOverlaySize;
+}
+
+/*
+ * IsProgressMeterFilled - Determines if a progress meter is at 100% fill based
+ * on a comparison of the current value and maximum.
+ */
+static bool IsProgressMeterFilled(nsIFrame* aFrame) {
+  NS_ENSURE_TRUE(aFrame, false);
+  nsIFrame* parentFrame = aFrame->GetParent();
+  NS_ENSURE_TRUE(parentFrame, false);
+  return nsNativeTheme::GetProgressValue(parentFrame) ==
+         nsNativeTheme::GetProgressMaxValue(parentFrame);
+}
+
+/*
+ * CalculateProgressOverlayRect - returns the padded overlay animation rect
+ * used in rendering progress bars. Resulting rects are used in rendering
+ * vista+ pulse overlays and indeterminate progress meters. Graphics should
+ * be rendered at the origin.
+ */
+RECT nsNativeThemeWin::CalculateProgressOverlayRect(nsIFrame* aFrame,
+                                                    RECT* aWidgetRect,
+                                                    bool aIsVertical,
+                                                    bool aIsIndeterminate,
+                                                    bool aIsClassic) {
+  NS_ASSERTION(aFrame, "bad frame pointer");
+  NS_ASSERTION(aWidgetRect, "bad rect pointer");
+
+  int32_t frameSize = aIsVertical ? aWidgetRect->bottom - aWidgetRect->top
+                                  : aWidgetRect->right - aWidgetRect->left;
+
+  // Recycle a set of progress pulse timers - these timers control the position
+  // of all progress overlays and indeterminate chunks that get rendered.
+  double span = aIsIndeterminate ? kProgressIndeterminateTimeSpan
+                                 : kProgressDeterminateTimeSpan;
+  TimeDuration period;
+  if (!aIsIndeterminate) {
+    if (TimeStamp::Now() >
+        (mProgressDeterminateTimeStamp + TimeDuration::FromSeconds(span))) {
+      mProgressDeterminateTimeStamp = TimeStamp::Now();
+    }
+    period = TimeStamp::Now() - mProgressDeterminateTimeStamp;
+  } else {
+    if (TimeStamp::Now() >
+        (mProgressIndeterminateTimeStamp + TimeDuration::FromSeconds(span))) {
+      mProgressIndeterminateTimeStamp = TimeStamp::Now();
+    }
+    period = TimeStamp::Now() - mProgressIndeterminateTimeStamp;
+  }
+
+  double percent = period / TimeDuration::FromSeconds(span);
+
+  if (!aIsVertical && IsFrameRTL(aFrame)) percent = 1 - percent;
+
+  RECT overlayRect = *aWidgetRect;
+  int32_t overlaySize;
+  if (!aIsClassic) {
+    overlaySize = GetProgressOverlaySize(aIsVertical, aIsIndeterminate);
+  } else {
+    overlaySize = kProgressClassicOverlaySize;
+  }
+
+  // Calculate a bounds that is larger than the meters frame such that the
+  // overlay starts and ends completely off the edge of the frame:
+  // [overlay][frame][overlay]
+  // This also yields a nice delay on rotation. Use overlaySize as the minimum
+  // size for [overlay] based on the graphics dims. If [frame] is larger, use
+  // the frame size instead.
+  int trackWidth = frameSize > overlaySize ? frameSize : overlaySize;
+  if (!aIsVertical) {
+    int xPos = aWidgetRect->left - trackWidth;
+    xPos += (int)ceil(((double)(trackWidth * 2) * percent));
+    overlayRect.left = xPos;
+    overlayRect.right = xPos + overlaySize;
+  } else {
+    int yPos = aWidgetRect->bottom + trackWidth;
+    yPos -= (int)ceil(((double)(trackWidth * 2) * percent));
+    overlayRect.bottom = yPos;
+    overlayRect.top = yPos - overlaySize;
+  }
+  return overlayRect;
+}
+
+/*
+ * DrawProgressMeter - render an appropriate progress meter based on progress
+ * meter style, orientation, and os. Note, this does not render the underlying
+ * progress track.
+ *
+ * @param aFrame       the widget frame
+ * @param aAppearance  type of widget
+ * @param aTheme       progress theme handle
+ * @param aHdc         hdc returned by gfxWindowsNativeDrawing
+ * @param aPart        the PP_X progress part
+ * @param aState       the theme state
+ * @param aWidgetRect  bounding rect for the widget
+ * @param aClipRect    dirty rect that needs drawing.
+ * @param aAppUnits    app units per device pixel
+ */
+void nsNativeThemeWin::DrawThemedProgressMeter(
+    nsIFrame* aFrame, StyleAppearance aAppearance, HANDLE aTheme, HDC aHdc,
+    int aPart, int aState, RECT* aWidgetRect, RECT* aClipRect) {
+  if (!aFrame || !aTheme || !aHdc) return;
+
+  NS_ASSERTION(aWidgetRect, "bad rect pointer");
+  NS_ASSERTION(aClipRect, "bad clip rect pointer");
+
+  RECT adjWidgetRect, adjClipRect;
+  adjWidgetRect = *aWidgetRect;
+  adjClipRect = *aClipRect;
+
+  nsIFrame* parentFrame = aFrame->GetParent();
+  if (!parentFrame) {
+    // We have no parent to work with, just bail.
+    NS_WARNING("No parent frame for progress rendering. Can't paint.");
+    return;
+  }
+
+  ElementState elementState = GetContentState(parentFrame, aAppearance);
+  bool vertical = IsVerticalProgress(parentFrame);
+  bool indeterminate = elementState.HasState(ElementState::INDETERMINATE);
+  bool animate = indeterminate;
+
+  // Vista and up progress meter is fill style, rendered here. We render
+  // the pulse overlay in the follow up section below.
+  DrawThemeBackground(aTheme, aHdc, aPart, aState, &adjWidgetRect,
+                      &adjClipRect);
+  if (!IsProgressMeterFilled(aFrame)) {
+    animate = true;
+  }
+
+  if (animate) {
+    // Indeterminate rendering
+    int32_t overlayPart = GetProgressOverlayStyle(vertical);
+    RECT overlayRect = CalculateProgressOverlayRect(
+        aFrame, &adjWidgetRect, vertical, indeterminate, false);
+    DrawThemeBackground(aTheme, aHdc, overlayPart, aState, &overlayRect,
+                        &adjClipRect);
+
+    if (!QueueAnimatedContentForRefresh(aFrame->GetContent(), 60)) {
+      NS_WARNING("unable to animate progress widget!");
+    }
+  }
+}
+
+LayoutDeviceIntMargin nsNativeThemeWin::GetCachedWidgetBorder(
+    HTHEME aTheme, nsUXThemeClass aThemeClass, StyleAppearance aAppearance,
+    int32_t aPart, int32_t aState) {
+  int32_t cacheIndex = aThemeClass * THEME_PART_DISTINCT_VALUE_COUNT + aPart;
+  int32_t cacheBitIndex = cacheIndex / 8;
+  uint8_t cacheBit = 1u << (cacheIndex % 8);
+
+  if (mBorderCacheValid[cacheBitIndex] & cacheBit) {
+    return mBorderCache[cacheIndex];
+  }
+
+  // Get our info.
+  RECT outerRect;  // Create a fake outer rect.
+  outerRect.top = outerRect.left = 100;
+  outerRect.right = outerRect.bottom = 200;
+  RECT contentRect(outerRect);
+  HRESULT res = GetThemeBackgroundContentRect(aTheme, nullptr, aPart, aState,
+                                              &outerRect, &contentRect);
+
+  if (FAILED(res)) {
+    return LayoutDeviceIntMargin();
+  }
+
+  // Now compute the delta in each direction and place it in our
+  // nsIntMargin struct.
+  LayoutDeviceIntMargin result;
+  result.top = contentRect.top - outerRect.top;
+  result.bottom = outerRect.bottom - contentRect.bottom;
+  result.left = contentRect.left - outerRect.left;
+  result.right = outerRect.right - contentRect.right;
+
+  mBorderCacheValid[cacheBitIndex] |= cacheBit;
+  mBorderCache[cacheIndex] = result;
+
+  return result;
+}
+
+nsresult nsNativeThemeWin::GetCachedMinimumWidgetSize(
+    nsIFrame* aFrame, HANDLE aTheme, nsUXThemeClass aThemeClass,
+    StyleAppearance aAppearance, int32_t aPart, int32_t aState,
+    THEMESIZE aSizeReq, mozilla::LayoutDeviceIntSize* aResult) {
+  int32_t cachePart = aPart;
+
+  if (aAppearance == StyleAppearance::Button && aSizeReq == TS_MIN) {
+    // In practice, StyleAppearance::Button is the only widget type which has an
+    // aSizeReq that varies for us, and it can only be TS_MIN or TS_TRUE. Just
+    // stuff that extra bit into the aPart part of the cache, since BP_Count is
+    // well below THEME_PART_DISTINCT_VALUE_COUNT anyway.
+    cachePart = BP_Count;
+  }
+
+  MOZ_ASSERT(aPart < THEME_PART_DISTINCT_VALUE_COUNT);
+  int32_t cacheIndex =
+      aThemeClass * THEME_PART_DISTINCT_VALUE_COUNT + cachePart;
+  int32_t cacheBitIndex = cacheIndex / 8;
+  uint8_t cacheBit = 1u << (cacheIndex % 8);
+
+  if (mMinimumWidgetSizeCacheValid[cacheBitIndex] & cacheBit) {
+    *aResult = mMinimumWidgetSizeCache[cacheIndex];
+    return NS_OK;
+  }
+
+  HDC hdc = ::GetDC(NULL);
+  if (!hdc) {
+    return NS_ERROR_FAILURE;
+  }
+
+  SIZE sz;
+  GetThemePartSize(aTheme, hdc, aPart, aState, nullptr, aSizeReq, &sz);
+  aResult->width = sz.cx;
+  aResult->height = sz.cy;
+
+  ::ReleaseDC(nullptr, hdc);
+
+  mMinimumWidgetSizeCacheValid[cacheBitIndex] |= cacheBit;
+  mMinimumWidgetSizeCache[cacheIndex] = *aResult;
+
+  return NS_OK;
+}
+
+mozilla::Maybe<nsUXThemeClass> nsNativeThemeWin::GetThemeClass(
+    StyleAppearance aAppearance) {
+  switch (aAppearance) {
+    case StyleAppearance::Button:
+      return Some(eUXButton);
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+      return Some(eUXEdit);
+    case StyleAppearance::Toolbox:
+      return Some(eUXRebar);
+    case StyleAppearance::Toolbar:
+    case StyleAppearance::Toolbarbutton:
+    case StyleAppearance::Separator:
+      return Some(eUXToolbar);
+    case StyleAppearance::ProgressBar:
+    case StyleAppearance::Progresschunk:
+      return Some(eUXProgress);
+    case StyleAppearance::Tab:
+    case StyleAppearance::Tabpanel:
+    case StyleAppearance::Tabpanels:
+      return Some(eUXTab);
+    case StyleAppearance::Range:
+    case StyleAppearance::RangeThumb:
+      return Some(eUXTrackbar);
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+      return Some(eUXCombobox);
+    case StyleAppearance::Treeheadercell:
+      return Some(eUXHeader);
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Treeview:
+    case StyleAppearance::Treetwistyopen:
+    case StyleAppearance::Treeitem:
+      return Some(eUXListview);
+    default:
+      return Nothing();
+  }
+}
+
+HANDLE
+nsNativeThemeWin::GetTheme(StyleAppearance aAppearance) {
+  mozilla::Maybe<nsUXThemeClass> themeClass = GetThemeClass(aAppearance);
+  if (themeClass.isNothing()) {
+    return nullptr;
+  }
+  return nsUXThemeData::GetTheme(themeClass.value());
+}
+
+int32_t nsNativeThemeWin::StandardGetState(nsIFrame* aFrame,
+                                           StyleAppearance aAppearance,
+                                           bool wantFocused) {
+  ElementState elementState = GetContentState(aFrame, aAppearance);
+  if (elementState.HasAllStates(ElementState::HOVER | ElementState::ACTIVE)) {
+    return TS_ACTIVE;
+  }
+  if (elementState.HasState(ElementState::HOVER)) {
+    return TS_HOVER;
+  }
+  if (wantFocused) {
+    if (elementState.HasState(ElementState::FOCUSRING)) {
+      return TS_FOCUSED;
+    }
+    // On Windows, focused buttons are always drawn as such by the native
+    // theme, that's why we check ElementState::FOCUS instead of
+    // ElementState::FOCUSRING.
+    if (aAppearance == StyleAppearance::Button &&
+        elementState.HasState(ElementState::FOCUS)) {
+      return TS_FOCUSED;
+    }
+  }
+
+  return TS_NORMAL;
+}
+
+bool nsNativeThemeWin::IsMenuActive(nsIFrame* aFrame,
+                                    StyleAppearance aAppearance) {
+  nsIContent* content = aFrame->GetContent();
+  if (content->IsXULElement() &&
+      content->NodeInfo()->Equals(nsGkAtoms::richlistitem))
+    return CheckBooleanAttr(aFrame, nsGkAtoms::selected);
+
+  return CheckBooleanAttr(aFrame, nsGkAtoms::menuactive);
+}
+
+/**
+ * aPart is filled in with the UXTheme part code. On return, values > 0
+ * are the actual UXTheme part code; -1 means the widget will be drawn by
+ * us; 0 means that we should use part code 0, which isn't a real part code
+ * but elicits some kind of default behaviour from UXTheme when drawing
+ * (but isThemeBackgroundPartiallyTransparent may not work).
+ */
+nsresult nsNativeThemeWin::GetThemePartAndState(nsIFrame* aFrame,
+                                                StyleAppearance aAppearance,
+                                                int32_t& aPart,
+                                                int32_t& aState) {
+  switch (aAppearance) {
+    case StyleAppearance::Button: {
+      aPart = BP_BUTTON;
+      if (!aFrame) {
+        aState = TS_NORMAL;
+        return NS_OK;
+      }
+
+      ElementState elementState = GetContentState(aFrame, aAppearance);
+      if (elementState.HasState(ElementState::DISABLED)) {
+        aState = TS_DISABLED;
+        return NS_OK;
+      }
+      if (IsOpenButton(aFrame) || IsCheckedButton(aFrame)) {
+        aState = TS_ACTIVE;
+        return NS_OK;
+      }
+
+      aState = StandardGetState(aFrame, aAppearance, true);
+
+      // Check for default dialog buttons.  These buttons should always look
+      // focused.
+      if (aState == TS_NORMAL && IsDefaultButton(aFrame)) aState = TS_FOCUSED;
+      return NS_OK;
+    }
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea: {
+      ElementState elementState = GetContentState(aFrame, aAppearance);
+
+      /* Note: the NOSCROLL type has a rounded corner in each corner.  The more
+       * specific HSCROLL, VSCROLL, HVSCROLL types have side and/or top/bottom
+       * edges rendered as straight horizontal lines with sharp corners to
+       * accommodate a scrollbar.  However, the scrollbar gets rendered on top
+       * of this for us, so we don't care, and can just use NOSCROLL here.
+       */
+      aPart = TFP_EDITBORDER_NOSCROLL;
+
+      if (!aFrame) {
+        aState = TFS_EDITBORDER_NORMAL;
+      } else if (elementState.HasState(ElementState::DISABLED)) {
+        aState = TFS_EDITBORDER_DISABLED;
+      } else if (IsReadOnly(aFrame)) {
+        /* no special read-only state */
+        aState = TFS_EDITBORDER_NORMAL;
+      } else if (elementState.HasAtLeastOneOfStates(ElementState::ACTIVE |
+                                                    ElementState::FOCUSRING)) {
+        aState = TFS_EDITBORDER_FOCUSED;
+      } else if (elementState.HasState(ElementState::HOVER)) {
+        aState = TFS_EDITBORDER_HOVER;
+      } else {
+        aState = TFS_EDITBORDER_NORMAL;
+      }
+
+      return NS_OK;
+    }
+    case StyleAppearance::ProgressBar: {
+      bool vertical = IsVerticalProgress(aFrame);
+      aPart = vertical ? PP_BARVERT : PP_BAR;
+      aState = PBBS_NORMAL;
+      return NS_OK;
+    }
+    case StyleAppearance::Progresschunk: {
+      nsIFrame* parentFrame = aFrame->GetParent();
+      if (IsVerticalProgress(parentFrame)) {
+        aPart = PP_FILLVERT;
+      } else {
+        aPart = PP_FILL;
+      }
+
+      aState = PBBVS_NORMAL;
+      return NS_OK;
+    }
+    case StyleAppearance::Toolbarbutton: {
+      aPart = BP_BUTTON;
+      if (!aFrame) {
+        aState = TS_NORMAL;
+        return NS_OK;
+      }
+
+      ElementState elementState = GetContentState(aFrame, aAppearance);
+      if (elementState.HasState(ElementState::DISABLED)) {
+        aState = TS_DISABLED;
+        return NS_OK;
+      }
+      if (IsOpenButton(aFrame)) {
+        aState = TS_ACTIVE;
+        return NS_OK;
+      }
+
+      if (elementState.HasAllStates(ElementState::HOVER | ElementState::ACTIVE))
+        aState = TS_ACTIVE;
+      else if (elementState.HasState(ElementState::HOVER)) {
+        if (IsCheckedButton(aFrame))
+          aState = TB_HOVER_CHECKED;
+        else
+          aState = TS_HOVER;
+      } else {
+        if (IsCheckedButton(aFrame))
+          aState = TB_CHECKED;
+        else
+          aState = TS_NORMAL;
+      }
+
+      return NS_OK;
+    }
+    case StyleAppearance::Separator: {
+      aPart = TP_SEPARATOR;
+      aState = TS_NORMAL;
+      return NS_OK;
+    }
+    case StyleAppearance::Range: {
+      if (IsRangeHorizontal(aFrame)) {
+        aPart = TKP_TRACK;
+        aState = TRS_NORMAL;
+      } else {
+        aPart = TKP_TRACKVERT;
+        aState = TRVS_NORMAL;
+      }
+      return NS_OK;
+    }
+    case StyleAppearance::RangeThumb: {
+      if (IsRangeHorizontal(aFrame)) {
+        aPart = TKP_THUMBBOTTOM;
+      } else {
+        aPart = IsFrameRTL(aFrame) ? TKP_THUMBLEFT : TKP_THUMBRIGHT;
+      }
+      ElementState elementState = GetContentState(aFrame, aAppearance);
+      if (!aFrame) {
+        aState = TS_NORMAL;
+      } else if (elementState.HasState(ElementState::DISABLED)) {
+        aState = TKP_DISABLED;
+      } else {
+        if (elementState.HasState(
+                ElementState::ACTIVE))  // Hover is not also a requirement for
+                                        // the thumb, since the drag is not
+                                        // canceled when you move outside the
+                                        // thumb.
+          aState = TS_ACTIVE;
+        else if (elementState.HasState(ElementState::FOCUSRING))
+          aState = TKP_FOCUSED;
+        else if (elementState.HasState(ElementState::HOVER))
+          aState = TS_HOVER;
+        else
+          aState = TS_NORMAL;
+      }
+      return NS_OK;
+    }
+    case StyleAppearance::Toolbox: {
+      aState = 0;
+      aPart = RP_BACKGROUND;
+      return NS_OK;
+    }
+    case StyleAppearance::Toolbar: {
+      // Use -1 to indicate we don't wish to have the theme background drawn
+      // for this item. We will pass any nessessary information via aState,
+      // and will render the item using separate code.
+      aPart = -1;
+      aState = 0;
+      if (aFrame) {
+        nsIContent* content = aFrame->GetContent();
+        nsIContent* parent = content->GetParent();
+        // XXXzeniko hiding the first toolbar will result in an unwanted margin
+        if (parent && parent->GetFirstChild() == content) {
+          aState = 1;
+        }
+      }
+      return NS_OK;
+    }
+    case StyleAppearance::Treeview:
+    case StyleAppearance::Listbox: {
+      aPart = TREEVIEW_BODY;
+      aState = TS_NORMAL;
+      return NS_OK;
+    }
+    case StyleAppearance::Tabpanels: {
+      aPart = TABP_PANELS;
+      aState = TS_NORMAL;
+      return NS_OK;
+    }
+    case StyleAppearance::Tabpanel: {
+      aPart = TABP_PANEL;
+      aState = TS_NORMAL;
+      return NS_OK;
+    }
+    case StyleAppearance::Tab: {
+      aPart = TABP_TAB;
+      if (!aFrame) {
+        aState = TS_NORMAL;
+        return NS_OK;
+      }
+
+      ElementState elementState = GetContentState(aFrame, aAppearance);
+      if (elementState.HasState(ElementState::DISABLED)) {
+        aState = TS_DISABLED;
+        return NS_OK;
+      }
+
+      if (IsSelectedTab(aFrame)) {
+        aPart = TABP_TAB_SELECTED;
+        aState = TS_ACTIVE;  // The selected tab is always "pressed".
+      } else
+        aState = StandardGetState(aFrame, aAppearance, true);
+
+      return NS_OK;
+    }
+    case StyleAppearance::Treeheadercell: {
+      aPart = 1;
+      if (!aFrame) {
+        aState = TS_NORMAL;
+        return NS_OK;
+      }
+
+      aState = StandardGetState(aFrame, aAppearance, true);
+
+      return NS_OK;
+    }
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Menulist: {
+      nsIContent* content = aFrame->GetContent();
+      bool useDropBorder = content && content->IsHTMLElement();
+      ElementState elementState = GetContentState(aFrame, aAppearance);
+
+      /* On Vista/Win7, we use CBP_DROPBORDER instead of DROPFRAME for HTML
+       * content or for editable menulists; this gives us the thin outline,
+       * instead of the gradient-filled background */
+      if (useDropBorder)
+        aPart = CBP_DROPBORDER;
+      else
+        aPart = CBP_DROPFRAME;
+
+      if (elementState.HasState(ElementState::DISABLED)) {
+        aState = TS_DISABLED;
+      } else if (IsReadOnly(aFrame)) {
+        aState = TS_NORMAL;
+      } else if (IsOpenButton(aFrame)) {
+        aState = TS_ACTIVE;
+      } else if (useDropBorder &&
+                 elementState.HasState(ElementState::FOCUSRING)) {
+        aState = TS_ACTIVE;
+      } else if (elementState.HasAllStates(ElementState::HOVER |
+                                           ElementState::ACTIVE)) {
+        aState = TS_ACTIVE;
+      } else if (elementState.HasState(ElementState::HOVER)) {
+        aState = TS_HOVER;
+      } else {
+        aState = TS_NORMAL;
+      }
+
+      return NS_OK;
+    }
+    default:
+      aPart = 0;
+      aState = 0;
+      return NS_ERROR_FAILURE;
+  }
+}
+
+static bool AssumeThemePartAndStateAreTransparent(int32_t aPart,
+                                                  int32_t aState) {
+  if (!nsUXThemeData::IsHighContrastOn() && aPart == MENU_POPUPITEM &&
+      aState == MBI_NORMAL) {
+    return true;
+  }
+  return false;
+}
+
+// When running with per-monitor DPI (on Win8.1+), and rendering on a display
+// with a different DPI setting from the system's default scaling, we need to
+// apply scaling to native-themed elements as the Windows theme APIs assume
+// the system default resolution.
+static inline double GetThemeDpiScaleFactor(nsPresContext* aPresContext) {
+  if (WinUtils::IsPerMonitorDPIAware() ||
+      StaticPrefs::layout_css_devPixelsPerPx() > 0.0) {
+    nsCOMPtr<nsIWidget> rootWidget = aPresContext->GetRootWidget();
+    if (rootWidget) {
+      double systemScale = WinUtils::SystemScaleFactor();
+      return rootWidget->GetDefaultScale().scale / systemScale;
+    }
+  }
+  return 1.0;
+}
+
+static inline double GetThemeDpiScaleFactor(nsIFrame* aFrame) {
+  return GetThemeDpiScaleFactor(aFrame->PresContext());
+}
+
+NS_IMETHODIMP
+nsNativeThemeWin::DrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
+                                       StyleAppearance aAppearance,
+                                       const nsRect& aRect,
+                                       const nsRect& aDirtyRect,
+                                       DrawOverflow aDrawOverflow) {
+  if (IsWidgetNonNative(aFrame, aAppearance) != NonNative::No) {
+    return Theme::DrawWidgetBackground(aContext, aFrame, aAppearance, aRect,
+                                       aDirtyRect, aDrawOverflow);
+  }
+
+  HANDLE theme = GetTheme(aAppearance);
+  if (!theme)
+    return ClassicDrawWidgetBackground(aContext, aFrame, aAppearance, aRect,
+                                       aDirtyRect);
+
+  // ^^ without the right sdk, assume xp theming and fall through.
+  int32_t part, state;
+  nsresult rv = GetThemePartAndState(aFrame, aAppearance, part, state);
+  if (NS_FAILED(rv)) return rv;
+
+  if (AssumeThemePartAndStateAreTransparent(part, state)) {
+    return NS_OK;
+  }
+
+  gfxContextMatrixAutoSaveRestore save(aContext);
+
+  double themeScale = GetThemeDpiScaleFactor(aFrame);
+  if (themeScale != 1.0) {
+    aContext->SetMatrix(
+        aContext->CurrentMatrix().PreScale(themeScale, themeScale));
+  }
+
+  gfxFloat p2a = gfxFloat(aFrame->PresContext()->AppUnitsPerDevPixel());
+  RECT widgetRect;
+  RECT clipRect;
+  gfxRect tr(aRect.X(), aRect.Y(), aRect.Width(), aRect.Height()),
+      dr(aDirtyRect.X(), aDirtyRect.Y(), aDirtyRect.Width(),
+         aDirtyRect.Height());
+
+  tr.Scale(1.0 / (p2a * themeScale));
+  dr.Scale(1.0 / (p2a * themeScale));
+
+  gfxWindowsNativeDrawing nativeDrawing(
+      aContext, dr, GetWidgetNativeDrawingFlags(aAppearance));
+
+RENDER_AGAIN:
+
+  HDC hdc = nativeDrawing.BeginNativeDrawing();
+  if (!hdc) return NS_ERROR_FAILURE;
+
+  nativeDrawing.TransformToNativeRect(tr, widgetRect);
+  nativeDrawing.TransformToNativeRect(dr, clipRect);
+
+#if 0
+  {
+    MOZ_LOG(gWindowsLog, LogLevel::Error,
+           (stderr, "xform: %f %f %f %f [%f %f]\n", m._11, m._21, m._12, m._22,
+            m._31, m._32));
+    MOZ_LOG(gWindowsLog, LogLevel::Error,
+           (stderr, "tr: [%d %d %d %d]\ndr: [%d %d %d %d]\noff: [%f %f]\n",
+            tr.x, tr.y, tr.width, tr.height, dr.x, dr.y, dr.width, dr.height,
+            offset.x, offset.y));
+  }
+#endif
+
+  if (aAppearance == StyleAppearance::Tab) {
+    // For left edge and right edge tabs, we need to adjust the widget
+    // rects and clip rects so that the edges don't get drawn.
+    bool isLeft = IsLeftToSelectedTab(aFrame);
+    bool isRight = !isLeft && IsRightToSelectedTab(aFrame);
+
+    if (isLeft || isRight) {
+      // HACK ALERT: There appears to be no way to really obtain this value, so
+      // we're forced to just use the default value for Luna (which also happens
+      // to be correct for all the other skins I've tried).
+      int32_t edgeSize = 2;
+
+      // Armed with the size of the edge, we now need to either shift to the
+      // left or to the right.  The clip rect won't include this extra area, so
+      // we know that we're effectively shifting the edge out of view (such that
+      // it won't be painted).
+      if (isLeft)
+        // The right edge should not be drawn.  Extend our rect by the edge
+        // size.
+        widgetRect.right += edgeSize;
+      else
+        // The left edge should not be drawn.  Move the widget rect's left coord
+        // back.
+        widgetRect.left -= edgeSize;
+    }
+  }
+
+  // widgetRect is the bounding box for a widget, yet the scale track is only
+  // a small portion of this size, so the edges of the scale need to be
+  // adjusted to the real size of the track.
+  if (aAppearance == StyleAppearance::Range) {
+    RECT contentRect;
+    GetThemeBackgroundContentRect(theme, hdc, part, state, &widgetRect,
+                                  &contentRect);
+
+    SIZE siz;
+    GetThemePartSize(theme, hdc, part, state, &widgetRect, TS_TRUE, &siz);
+
+    // When rounding is necessary, we round the position of the track
+    // away from the chevron of the thumb to make it look better.
+    if (IsRangeHorizontal(aFrame)) {
+      contentRect.top += (contentRect.bottom - contentRect.top - siz.cy) / 2;
+      contentRect.bottom = contentRect.top + siz.cy;
+    } else {
+      if (!IsFrameRTL(aFrame)) {
+        contentRect.left += (contentRect.right - contentRect.left - siz.cx) / 2;
+        contentRect.right = contentRect.left + siz.cx;
+      } else {
+        contentRect.right -=
+            (contentRect.right - contentRect.left - siz.cx) / 2;
+        contentRect.left = contentRect.right - siz.cx;
+      }
+    }
+
+    DrawThemeBackground(theme, hdc, part, state, &contentRect, &clipRect);
+  } else if (aAppearance == StyleAppearance::NumberInput ||
+             aAppearance == StyleAppearance::Textfield ||
+             aAppearance == StyleAppearance::Textarea) {
+    DrawThemeBackground(theme, hdc, part, state, &widgetRect, &clipRect);
+
+    if (state == TFS_EDITBORDER_DISABLED) {
+      InflateRect(&widgetRect, -1, -1);
+      ::FillRect(hdc, &widgetRect, reinterpret_cast<HBRUSH>(COLOR_BTNFACE + 1));
+    }
+  } else if (aAppearance == StyleAppearance::ProgressBar) {
+    // DrawThemeBackground renders each corner with a solid white pixel.
+    // Restore these pixels to the underlying color. Tracks are rendered
+    // using alpha recovery, so this makes the corners transparent.
+    COLORREF color;
+    color = GetPixel(hdc, widgetRect.left, widgetRect.top);
+    DrawThemeBackground(theme, hdc, part, state, &widgetRect, &clipRect);
+    SetPixel(hdc, widgetRect.left, widgetRect.top, color);
+    SetPixel(hdc, widgetRect.right - 1, widgetRect.top, color);
+    SetPixel(hdc, widgetRect.right - 1, widgetRect.bottom - 1, color);
+    SetPixel(hdc, widgetRect.left, widgetRect.bottom - 1, color);
+  } else if (aAppearance == StyleAppearance::Progresschunk) {
+    DrawThemedProgressMeter(aFrame, aAppearance, theme, hdc, part, state,
+                            &widgetRect, &clipRect);
+  }
+  // If part is negative, the element wishes us to not render a themed
+  // background, instead opting to be drawn specially below.
+  else if (part >= 0) {
+    DrawThemeBackground(theme, hdc, part, state, &widgetRect, &clipRect);
+  }
+
+  // Draw focus rectangles for range elements
+  // XXX it'd be nice to draw these outside of the frame
+  if (aAppearance == StyleAppearance::Range) {
+    ElementState contentState = GetContentState(aFrame, aAppearance);
+
+    if (contentState.HasState(ElementState::FOCUSRING)) {
+      POINT vpOrg;
+      HPEN hPen = nullptr;
+
+      uint8_t id = SaveDC(hdc);
+
+      ::SelectClipRgn(hdc, nullptr);
+      ::GetViewportOrgEx(hdc, &vpOrg);
+      ::SetBrushOrgEx(hdc, vpOrg.x + widgetRect.left, vpOrg.y + widgetRect.top,
+                      nullptr);
+      ::SetTextColor(hdc, 0);
+      ::DrawFocusRect(hdc, &widgetRect);
+      ::RestoreDC(hdc, id);
+      if (hPen) {
+        ::DeleteObject(hPen);
+      }
+    }
+  } else if (aAppearance == StyleAppearance::Toolbar && state == 0) {
+    // Draw toolbar separator lines above all toolbars except the first one.
+    // The lines are part of the Rebar theme, which is loaded for
+    // StyleAppearance::Toolbox.
+    theme = GetTheme(StyleAppearance::Toolbox);
+    if (!theme) return NS_ERROR_FAILURE;
+
+    widgetRect.bottom = widgetRect.top + TB_SEPARATOR_HEIGHT;
+    DrawThemeEdge(theme, hdc, RP_BAND, 0, &widgetRect, EDGE_ETCHED, BF_TOP,
+                  nullptr);
+  }
+
+  nativeDrawing.EndNativeDrawing();
+
+  if (nativeDrawing.ShouldRenderAgain()) goto RENDER_AGAIN;
+
+  nativeDrawing.PaintToContext();
+
+  return NS_OK;
+}
+
+bool nsNativeThemeWin::CreateWebRenderCommandsForWidget(
+    wr::DisplayListBuilder& aBuilder, wr::IpcResourceUpdateQueue& aResources,
+    const layers::StackingContextHelper& aSc,
+    layers::RenderRootStateManager* aManager, nsIFrame* aFrame,
+    StyleAppearance aAppearance, const nsRect& aRect) {
+  if (IsWidgetNonNative(aFrame, aAppearance) != NonNative::No) {
+    return Theme::CreateWebRenderCommandsForWidget(
+        aBuilder, aResources, aSc, aManager, aFrame, aAppearance, aRect);
+  }
+  return false;
+}
+
+static void ScaleForFrameDPI(LayoutDeviceIntMargin* aMargin, nsIFrame* aFrame) {
+  double themeScale = GetThemeDpiScaleFactor(aFrame);
+  if (themeScale != 1.0) {
+    aMargin->top = NSToIntRound(aMargin->top * themeScale);
+    aMargin->left = NSToIntRound(aMargin->left * themeScale);
+    aMargin->bottom = NSToIntRound(aMargin->bottom * themeScale);
+    aMargin->right = NSToIntRound(aMargin->right * themeScale);
+  }
+}
+
+static void ScaleForFrameDPI(LayoutDeviceIntSize* aSize, nsIFrame* aFrame) {
+  double themeScale = GetThemeDpiScaleFactor(aFrame);
+  if (themeScale != 1.0) {
+    aSize->width = NSToIntRound(aSize->width * themeScale);
+    aSize->height = NSToIntRound(aSize->height * themeScale);
+  }
+}
+
+LayoutDeviceIntMargin nsNativeThemeWin::GetWidgetBorder(
+    nsDeviceContext* aContext, nsIFrame* aFrame, StyleAppearance aAppearance) {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return Theme::GetWidgetBorder(aContext, aFrame, aAppearance);
+  }
+
+  LayoutDeviceIntMargin result;
+  mozilla::Maybe<nsUXThemeClass> themeClass = GetThemeClass(aAppearance);
+  HTHEME theme = NULL;
+  if (!themeClass.isNothing()) {
+    theme = nsUXThemeData::GetTheme(themeClass.value());
+  }
+  if (!theme) {
+    result = ClassicGetWidgetBorder(aContext, aFrame, aAppearance);
+    ScaleForFrameDPI(&result, aFrame);
+    return result;
+  }
+
+  if (!WidgetIsContainer(aAppearance) ||
+      aAppearance == StyleAppearance::Toolbox ||
+      aAppearance == StyleAppearance::Tabpanel)
+    return result;  // Don't worry about it.
+
+  int32_t part, state;
+  nsresult rv = GetThemePartAndState(aFrame, aAppearance, part, state);
+  if (NS_FAILED(rv)) return result;
+
+  if (aAppearance == StyleAppearance::Toolbar) {
+    // make space for the separator line above all toolbars but the first
+    if (state == 0) result.top = TB_SEPARATOR_HEIGHT;
+    return result;
+  }
+
+  result = GetCachedWidgetBorder(theme, themeClass.value(), aAppearance, part,
+                                 state);
+
+  // Remove the edges for tabs that are before or after the selected tab,
+  if (aAppearance == StyleAppearance::Tab) {
+    if (IsLeftToSelectedTab(aFrame))
+      // Remove the right edge, since we won't be drawing it.
+      result.right = 0;
+    else if (IsRightToSelectedTab(aFrame))
+      // Remove the left edge, since we won't be drawing it.
+      result.left = 0;
+  }
+
+  if (aFrame && (aAppearance == StyleAppearance::NumberInput ||
+                 aAppearance == StyleAppearance::Textfield ||
+                 aAppearance == StyleAppearance::Textarea)) {
+    nsIContent* content = aFrame->GetContent();
+    if (content && content->IsHTMLElement()) {
+      // We need to pad textfields by 1 pixel, since the caret will draw
+      // flush against the edge by default if we don't.
+      result.top.value++;
+      result.left.value++;
+      result.bottom.value++;
+      result.right.value++;
+    }
+  }
+
+  ScaleForFrameDPI(&result, aFrame);
+  return result;
+}
+
+bool nsNativeThemeWin::GetWidgetPadding(nsDeviceContext* aContext,
+                                        nsIFrame* aFrame,
+                                        StyleAppearance aAppearance,
+                                        LayoutDeviceIntMargin* aResult) {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return Theme::GetWidgetPadding(aContext, aFrame, aAppearance, aResult);
+  }
+
+  bool ok = true;
+  HANDLE theme = GetTheme(aAppearance);
+  if (!theme) {
+    ok = ClassicGetWidgetPadding(aContext, aFrame, aAppearance, aResult);
+    ScaleForFrameDPI(aResult, aFrame);
+    return ok;
+  }
+
+  /* textfields need extra pixels on all sides, otherwise they wrap their
+   * content too tightly.  The actual border is drawn 1px inside the specified
+   * rectangle, so Gecko will end up making the contents look too small.
+   * Instead, we add 2px padding for the contents and fix this. (Used to be 1px
+   * added, see bug 430212)
+   */
+  if (aAppearance == StyleAppearance::NumberInput ||
+      aAppearance == StyleAppearance::Textfield ||
+      aAppearance == StyleAppearance::Textarea) {
+    aResult->top = aResult->bottom = 2;
+    aResult->left = aResult->right = 2;
+    ScaleForFrameDPI(aResult, aFrame);
+    return ok;
+  } else if (IsHTMLContent(aFrame) &&
+             (aAppearance == StyleAppearance::Menulist ||
+              aAppearance == StyleAppearance::MenulistButton)) {
+    /* For content menulist controls, we need an extra pixel so that we have
+     * room to draw our focus rectangle stuff. Otherwise, the focus rect might
+     * overlap the control's border.
+     */
+    aResult->top = aResult->bottom = 1;
+    aResult->left = aResult->right = 1;
+    ScaleForFrameDPI(aResult, aFrame);
+    return ok;
+  }
+
+  int32_t right, left, top, bottom;
+  right = left = top = bottom = 0;
+  switch (aAppearance) {
+    case StyleAppearance::Button:
+      if (aFrame->GetContent()->IsXULElement()) {
+        top = 2;
+        bottom = 3;
+      }
+      left = right = 5;
+      break;
+    default:
+      return false;
+  }
+
+  if (IsFrameRTL(aFrame)) {
+    aResult->right = left;
+    aResult->left = right;
+  } else {
+    aResult->right = right;
+    aResult->left = left;
+  }
+  aResult->top = top;
+  aResult->bottom = bottom;
+
+  ScaleForFrameDPI(aResult, aFrame);
+  return ok;
+}
+
+bool nsNativeThemeWin::GetWidgetOverflow(nsDeviceContext* aContext,
+                                         nsIFrame* aFrame,
+                                         StyleAppearance aAppearance,
+                                         nsRect* aOverflowRect) {
+  if (IsWidgetNonNative(aFrame, aAppearance) != NonNative::No) {
+    return Theme::GetWidgetOverflow(aContext, aFrame, aAppearance,
+                                    aOverflowRect);
+  }
+
+  /* This is disabled for now, because it causes invalidation problems --
+   * see bug 420381.  The effect of not updating the overflow area is that
+   * for dropdown buttons in content areas, there is a 1px border on 3 sides
+   * where, if invalidated, the dropdown control probably won't be repainted.
+   * This is fairly minor, as by default there is nothing in that area, and
+   * a border only shows up if the widget is being hovered.
+   *
+   * TODO(jwatt): Figure out what do to about
+   * StyleAppearance::MozMenulistArrowButton too.
+   */
+#if 0
+  /* We explicitly draw dropdown buttons in HTML content 1px bigger up, right,
+   * and bottom so that they overlap the dropdown's border like they're
+   * supposed to.
+   */
+  if (aAppearance == StyleAppearance::MenulistButton &&
+      IsHTMLContent(aFrame) &&
+      !IsWidgetStyled(aFrame->GetParent()->PresContext(),
+                      aFrame->GetParent(),
+                      StyleAppearance::Menulist))
+  {
+    int32_t p2a = aContext->AppUnitsPerDevPixel();
+    /* Note: no overflow on the left */
+    nsMargin m(p2a, p2a, p2a, 0);
+    aOverflowRect->Inflate (m);
+    return true;
+  }
+#endif
+
+  return false;
+}
+
+LayoutDeviceIntSize nsNativeThemeWin::GetMinimumWidgetSize(
+    nsPresContext* aPresContext, nsIFrame* aFrame,
+    StyleAppearance aAppearance) {
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return Theme::GetMinimumWidgetSize(aPresContext, aFrame, aAppearance);
+  }
+
+  mozilla::Maybe<nsUXThemeClass> themeClass = GetThemeClass(aAppearance);
+  HTHEME theme = NULL;
+  if (!themeClass.isNothing()) {
+    theme = nsUXThemeData::GetTheme(themeClass.value());
+  }
+  if (!theme) {
+    auto result = ClassicGetMinimumWidgetSize(aFrame, aAppearance);
+    ScaleForFrameDPI(&result, aFrame);
+    return result;
+  }
+
+  switch (aAppearance) {
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Toolbox:
+    case StyleAppearance::Toolbar:
+    case StyleAppearance::Progresschunk:
+    case StyleAppearance::Tabpanels:
+    case StyleAppearance::Tabpanel:
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Treeview:
+      return {};  // Don't worry about it.
+    default:
+      break;
+  }
+
+  // Call GetSystemMetrics to determine size for WinXP scrollbars
+  // (GetThemeSysSize API returns the optimal size for the theme, but
+  //  Windows appears to always use metrics when drawing standard scrollbars)
+  THEMESIZE sizeReq = TS_TRUE;  // Best-fit size
+  switch (aAppearance) {
+    case StyleAppearance::ProgressBar:
+      // Best-fit size for progress meters is too large for most
+      // themes. We want these widgets to be able to really shrink
+      // down, so use the min-size request value (of 0).
+      sizeReq = TS_MIN;
+      break;
+
+    case StyleAppearance::RangeThumb: {
+      LayoutDeviceIntSize result(12, 20);
+      if (!IsRangeHorizontal(aFrame)) {
+        std::swap(result.width, result.height);
+      }
+      ScaleForFrameDPI(&result, aFrame);
+      return result;
+    }
+
+    case StyleAppearance::Separator: {
+      // that's 2px left margin, 2px right margin and 2px separator
+      // (the margin is drawn as part of the separator, though)
+      LayoutDeviceIntSize result(6, 0);
+      ScaleForFrameDPI(&result, aFrame);
+      return result;
+    }
+
+    case StyleAppearance::Button:
+      // We should let HTML buttons shrink to their min size.
+      // FIXME bug 403934: We should probably really separate
+      // GetPreferredWidgetSize from GetMinimumWidgetSize, so callers can
+      // use the one they want.
+      if (aFrame->GetContent()->IsHTMLElement()) {
+        sizeReq = TS_MIN;
+      }
+      break;
+
+    default:
+      break;
+  }
+
+  int32_t part, state;
+  nsresult rv = GetThemePartAndState(aFrame, aAppearance, part, state);
+  if (NS_FAILED(rv)) {
+    return {};
+  }
+
+  LayoutDeviceIntSize result;
+  rv = GetCachedMinimumWidgetSize(aFrame, theme, themeClass.value(),
+                                  aAppearance, part, state, sizeReq, &result);
+  ScaleForFrameDPI(&result, aFrame);
+  return result;
+}
+
+NS_IMETHODIMP
+nsNativeThemeWin::WidgetStateChanged(nsIFrame* aFrame,
+                                     StyleAppearance aAppearance,
+                                     nsAtom* aAttribute, bool* aShouldRepaint,
+                                     const nsAttrValue* aOldValue) {
+  // Some widget types just never change state.
+  if (aAppearance == StyleAppearance::Toolbox ||
+      aAppearance == StyleAppearance::Toolbar ||
+      aAppearance == StyleAppearance::Progresschunk ||
+      aAppearance == StyleAppearance::ProgressBar ||
+      aAppearance == StyleAppearance::Tabpanels ||
+      aAppearance == StyleAppearance::Tabpanel ||
+      aAppearance == StyleAppearance::Separator) {
+    *aShouldRepaint = false;
+    return NS_OK;
+  }
+
+  // We need to repaint the dropdown arrow in vista HTML combobox controls when
+  // the control is closed to get rid of the hover effect.
+  if ((aAppearance == StyleAppearance::Menulist ||
+       aAppearance == StyleAppearance::MenulistButton) &&
+      nsNativeTheme::IsHTMLContent(aFrame)) {
+    *aShouldRepaint = true;
+    return NS_OK;
+  }
+
+  // XXXdwh Not sure what can really be done here.  Can at least guess for
+  // specific widgets that they're highly unlikely to have certain states.
+  // For example, a toolbar doesn't care about any states.
+  if (!aAttribute) {
+    // Hover/focus/active changed.  Always repaint.
+    *aShouldRepaint = true;
+  } else {
+    // Check the attribute to see if it's relevant.
+    // disabled, checked, dlgtype, default, etc.
+    *aShouldRepaint = false;
+    if (aAttribute == nsGkAtoms::disabled || aAttribute == nsGkAtoms::checked ||
+        aAttribute == nsGkAtoms::selected ||
+        aAttribute == nsGkAtoms::visuallyselected ||
+        aAttribute == nsGkAtoms::readonly || aAttribute == nsGkAtoms::open ||
+        aAttribute == nsGkAtoms::menuactive || aAttribute == nsGkAtoms::focused)
+      *aShouldRepaint = true;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsNativeThemeWin::ThemeChanged() {
+  nsUXThemeData::Invalidate();
+  memset(mBorderCacheValid, 0, sizeof(mBorderCacheValid));
+  memset(mMinimumWidgetSizeCacheValid, 0, sizeof(mMinimumWidgetSizeCacheValid));
+  mGutterSizeCacheValid = false;
+  return NS_OK;
+}
+
+bool nsNativeThemeWin::ThemeSupportsWidget(nsPresContext* aPresContext,
+                                           nsIFrame* aFrame,
+                                           StyleAppearance aAppearance) {
+  // XXXdwh We can go even further and call the API to ask if support exists for
+  // specific widgets.
+
+  if (IsWidgetAlwaysNonNative(aFrame, aAppearance)) {
+    return Theme::ThemeSupportsWidget(aPresContext, aFrame, aAppearance);
+  }
+
+  HANDLE theme = GetTheme(aAppearance);
+  if (theme || ClassicThemeSupportsWidget(aFrame, aAppearance))
+    // turn off theming for some HTML widgets styled by the page
+    return !IsWidgetStyled(aPresContext, aFrame, aAppearance);
+
+  return false;
+}
+
+bool nsNativeThemeWin::ThemeDrawsFocusForWidget(nsIFrame* aFrame,
+                                                StyleAppearance aAppearance) {
+  if (IsWidgetNonNative(aFrame, aAppearance) != NonNative::No) {
+    return Theme::ThemeDrawsFocusForWidget(aFrame, aAppearance);
+  }
+  switch (aAppearance) {
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::NumberInput:
+      return true;
+    default:
+      return false;
+  }
+}
+
+bool nsNativeThemeWin::ThemeNeedsComboboxDropmarker() { return true; }
+
+nsITheme::Transparency nsNativeThemeWin::GetWidgetTransparency(
+    nsIFrame* aFrame, StyleAppearance aAppearance) {
+  if (IsWidgetNonNative(aFrame, aAppearance) != NonNative::No) {
+    return Theme::GetWidgetTransparency(aFrame, aAppearance);
+  }
+
+  switch (aAppearance) {
+    case StyleAppearance::ProgressBar:
+    case StyleAppearance::Progresschunk:
+    case StyleAppearance::Range:
+      return eTransparent;
+    default:
+      break;
+  }
+
+  HANDLE theme = GetTheme(aAppearance);
+  // For the classic theme we don't really have a way of knowing
+  if (!theme) {
+    return eUnknownTransparency;
+  }
+
+  int32_t part, state;
+  nsresult rv = GetThemePartAndState(aFrame, aAppearance, part, state);
+  // Fail conservatively
+  NS_ENSURE_SUCCESS(rv, eUnknownTransparency);
+
+  if (part <= 0) {
+    // Not a real part code, so IsThemeBackgroundPartiallyTransparent may
+    // not work, so don't call it.
+    return eUnknownTransparency;
+  }
+
+  if (IsThemeBackgroundPartiallyTransparent(theme, part, state))
+    return eTransparent;
+  return eOpaque;
+}
+
+/* Windows 9x/NT/2000/Classic XP Theme Support */
+
+bool nsNativeThemeWin::ClassicThemeSupportsWidget(nsIFrame* aFrame,
+                                                  StyleAppearance aAppearance) {
+  switch (aAppearance) {
+    case StyleAppearance::Button:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Range:
+    case StyleAppearance::RangeThumb:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Treeview:
+    case StyleAppearance::ProgressBar:
+    case StyleAppearance::Progresschunk:
+    case StyleAppearance::Tab:
+    case StyleAppearance::Tabpanel:
+    case StyleAppearance::Tabpanels:
+      return true;
+    default:
+      return false;
+  }
+}
+
+LayoutDeviceIntMargin nsNativeThemeWin::ClassicGetWidgetBorder(
+    nsDeviceContext* aContext, nsIFrame* aFrame, StyleAppearance aAppearance) {
+  LayoutDeviceIntMargin result;
+  switch (aAppearance) {
+    case StyleAppearance::Button:
+      result.top = result.left = result.bottom = result.right = 2;
+      break;
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Treeview:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Tab:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+      result.top = result.left = result.bottom = result.right = 2;
+      break;
+    case StyleAppearance::ProgressBar:
+      result.top = result.left = result.bottom = result.right = 1;
+      break;
+    default:
+      result.top = result.bottom = result.left = result.right = 0;
+      break;
+  }
+  return result;
+}
+
+bool nsNativeThemeWin::ClassicGetWidgetPadding(nsDeviceContext* aContext,
+                                               nsIFrame* aFrame,
+                                               StyleAppearance aAppearance,
+                                               LayoutDeviceIntMargin* aResult) {
+  switch (aAppearance) {
+    case StyleAppearance::ProgressBar:
+      (*aResult).top = (*aResult).left = (*aResult).bottom = (*aResult).right =
+          1;
+      return true;
+    default:
+      return false;
+  }
+}
+
+LayoutDeviceIntSize nsNativeThemeWin::ClassicGetMinimumWidgetSize(
+    nsIFrame* aFrame, StyleAppearance aAppearance) {
+  LayoutDeviceIntSize result;
+  switch (aAppearance) {
+    case StyleAppearance::RangeThumb: {
+      if (IsRangeHorizontal(aFrame)) {
+        result.width = 12;
+        result.height = 20;
+      } else {
+        result.width = 20;
+        result.height = 12;
+      }
+      break;
+    }
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Button:
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Treeview:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Progresschunk:
+    case StyleAppearance::ProgressBar:
+    case StyleAppearance::Tab:
+    case StyleAppearance::Tabpanel:
+    case StyleAppearance::Tabpanels:
+      // no minimum widget size
+      break;
+
+    default:
+      break;
+  }
+  return result;
+}
+
+nsresult nsNativeThemeWin::ClassicGetThemePartAndState(
+    nsIFrame* aFrame, StyleAppearance aAppearance, int32_t& aPart,
+    int32_t& aState, bool& aFocused) {
+  aFocused = false;
+  switch (aAppearance) {
+    case StyleAppearance::Button: {
+      aPart = DFC_BUTTON;
+      aState = DFCS_BUTTONPUSH;
+      aFocused = false;
+
+      ElementState contentState = GetContentState(aFrame, aAppearance);
+      if (contentState.HasState(ElementState::DISABLED)) {
+        aState |= DFCS_INACTIVE;
+      } else if (IsOpenButton(aFrame)) {
+        aState |= DFCS_PUSHED;
+      } else if (IsCheckedButton(aFrame)) {
+        aState |= DFCS_CHECKED;
+      } else {
+        if (contentState.HasAllStates(ElementState::ACTIVE |
+                                      ElementState::HOVER)) {
+          aState |= DFCS_PUSHED;
+          // The down state is flat if the button is focusable
+          if (aFrame->StyleUI()->UserFocus() == StyleUserFocus::Normal) {
+            if (!aFrame->GetContent()->IsHTMLElement()) aState |= DFCS_FLAT;
+
+            aFocused = true;
+          }
+        }
+        // On Windows, focused buttons are always drawn as such by the native
+        // theme, that's why we check ElementState::FOCUS instead of
+        // ElementState::FOCUSRING.
+        if (contentState.HasState(ElementState::FOCUS) ||
+            (aState == DFCS_BUTTONPUSH && IsDefaultButton(aFrame))) {
+          aFocused = true;
+        }
+      }
+
+      return NS_OK;
+    }
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Treeview:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+    case StyleAppearance::Range:
+    case StyleAppearance::RangeThumb:
+    case StyleAppearance::Progresschunk:
+    case StyleAppearance::ProgressBar:
+    case StyleAppearance::Tab:
+    case StyleAppearance::Tabpanel:
+    case StyleAppearance::Tabpanels:
+      // these don't use DrawFrameControl
+      return NS_OK;
+    default:
+      return NS_ERROR_FAILURE;
+  }
+}
+
+// Draw classic Windows tab
+// (no system API for this, but DrawEdge can draw all the parts of a tab)
+static void DrawTab(HDC hdc, const RECT& R, int32_t aPosition, bool aSelected,
+                    bool aDrawLeft, bool aDrawRight) {
+  int32_t leftFlag, topFlag, rightFlag, lightFlag, shadeFlag;
+  RECT topRect, sideRect, bottomRect, lightRect, shadeRect;
+  int32_t selectedOffset, lOffset, rOffset;
+
+  selectedOffset = aSelected ? 1 : 0;
+  lOffset = aDrawLeft ? 2 : 0;
+  rOffset = aDrawRight ? 2 : 0;
+
+  // Get info for tab orientation/position (Left, Top, Right, Bottom)
+  switch (aPosition) {
+    case BF_LEFT:
+      leftFlag = BF_TOP;
+      topFlag = BF_LEFT;
+      rightFlag = BF_BOTTOM;
+      lightFlag = BF_DIAGONAL_ENDTOPRIGHT;
+      shadeFlag = BF_DIAGONAL_ENDBOTTOMRIGHT;
+
+      ::SetRect(&topRect, R.left, R.top + lOffset, R.right, R.bottom - rOffset);
+      ::SetRect(&sideRect, R.left + 2, R.top, R.right - 2 + selectedOffset,
+                R.bottom);
+      ::SetRect(&bottomRect, R.right - 2, R.top, R.right, R.bottom);
+      ::SetRect(&lightRect, R.left, R.top, R.left + 3, R.top + 3);
+      ::SetRect(&shadeRect, R.left + 1, R.bottom - 2, R.left + 2, R.bottom - 1);
+      break;
+    case BF_TOP:
+      leftFlag = BF_LEFT;
+      topFlag = BF_TOP;
+      rightFlag = BF_RIGHT;
+      lightFlag = BF_DIAGONAL_ENDTOPRIGHT;
+      shadeFlag = BF_DIAGONAL_ENDBOTTOMRIGHT;
+
+      ::SetRect(&topRect, R.left + lOffset, R.top, R.right - rOffset, R.bottom);
+      ::SetRect(&sideRect, R.left, R.top + 2, R.right,
+                R.bottom - 1 + selectedOffset);
+      ::SetRect(&bottomRect, R.left, R.bottom - 1, R.right, R.bottom);
+      ::SetRect(&lightRect, R.left, R.top, R.left + 3, R.top + 3);
+      ::SetRect(&shadeRect, R.right - 2, R.top + 1, R.right - 1, R.top + 2);
+      break;
+    case BF_RIGHT:
+      leftFlag = BF_TOP;
+      topFlag = BF_RIGHT;
+      rightFlag = BF_BOTTOM;
+      lightFlag = BF_DIAGONAL_ENDTOPLEFT;
+      shadeFlag = BF_DIAGONAL_ENDBOTTOMLEFT;
+
+      ::SetRect(&topRect, R.left, R.top + lOffset, R.right, R.bottom - rOffset);
+      ::SetRect(&sideRect, R.left + 2 - selectedOffset, R.top, R.right - 2,
+                R.bottom);
+      ::SetRect(&bottomRect, R.left, R.top, R.left + 2, R.bottom);
+      ::SetRect(&lightRect, R.right - 3, R.top, R.right - 1, R.top + 2);
+      ::SetRect(&shadeRect, R.right - 2, R.bottom - 3, R.right, R.bottom - 1);
+      break;
+    case BF_BOTTOM:
+      leftFlag = BF_LEFT;
+      topFlag = BF_BOTTOM;
+      rightFlag = BF_RIGHT;
+      lightFlag = BF_DIAGONAL_ENDTOPLEFT;
+      shadeFlag = BF_DIAGONAL_ENDBOTTOMLEFT;
+
+      ::SetRect(&topRect, R.left + lOffset, R.top, R.right - rOffset, R.bottom);
+      ::SetRect(&sideRect, R.left, R.top + 2 - selectedOffset, R.right,
+                R.bottom - 2);
+      ::SetRect(&bottomRect, R.left, R.top, R.right, R.top + 2);
+      ::SetRect(&lightRect, R.left, R.bottom - 3, R.left + 2, R.bottom - 1);
+      ::SetRect(&shadeRect, R.right - 2, R.bottom - 3, R.right, R.bottom - 1);
+      break;
+    default:
+      MOZ_CRASH();
+  }
+
+  // Background
+  ::FillRect(hdc, &R, (HBRUSH)(COLOR_3DFACE + 1));
+
+  // Tab "Top"
+  ::DrawEdge(hdc, &topRect, EDGE_RAISED, BF_SOFT | topFlag);
+
+  // Tab "Bottom"
+  if (!aSelected) ::DrawEdge(hdc, &bottomRect, EDGE_RAISED, BF_SOFT | topFlag);
+
+  // Tab "Sides"
+  if (!aDrawLeft) leftFlag = 0;
+  if (!aDrawRight) rightFlag = 0;
+  ::DrawEdge(hdc, &sideRect, EDGE_RAISED, BF_SOFT | leftFlag | rightFlag);
+
+  // Tab Diagonal Corners
+  if (aDrawLeft) ::DrawEdge(hdc, &lightRect, EDGE_RAISED, BF_SOFT | lightFlag);
+
+  if (aDrawRight) ::DrawEdge(hdc, &shadeRect, EDGE_RAISED, BF_SOFT | shadeFlag);
+}
+
+void nsNativeThemeWin::DrawCheckedRect(HDC hdc, const RECT& rc, int32_t fore,
+                                       int32_t back, HBRUSH defaultBack) {
+  static WORD patBits[8] = {0xaa, 0x55, 0xaa, 0x55, 0xaa, 0x55, 0xaa, 0x55};
+
+  HBITMAP patBmp = ::CreateBitmap(8, 8, 1, 1, patBits);
+  if (patBmp) {
+    HBRUSH brush = (HBRUSH)::CreatePatternBrush(patBmp);
+    if (brush) {
+      COLORREF oldForeColor = ::SetTextColor(hdc, ::GetSysColor(fore));
+      COLORREF oldBackColor = ::SetBkColor(hdc, ::GetSysColor(back));
+      POINT vpOrg;
+
+      ::UnrealizeObject(brush);
+      ::GetViewportOrgEx(hdc, &vpOrg);
+      ::SetBrushOrgEx(hdc, vpOrg.x + rc.left, vpOrg.y + rc.top, nullptr);
+      HBRUSH oldBrush = (HBRUSH)::SelectObject(hdc, brush);
+      ::FillRect(hdc, &rc, brush);
+      ::SetTextColor(hdc, oldForeColor);
+      ::SetBkColor(hdc, oldBackColor);
+      ::SelectObject(hdc, oldBrush);
+      ::DeleteObject(brush);
+    } else
+      ::FillRect(hdc, &rc, defaultBack);
+
+    ::DeleteObject(patBmp);
+  }
+}
+
+nsresult nsNativeThemeWin::ClassicDrawWidgetBackground(
+    gfxContext* aContext, nsIFrame* aFrame, StyleAppearance aAppearance,
+    const nsRect& aRect, const nsRect& aDirtyRect) {
+  int32_t part, state;
+  bool focused;
+  nsresult rv;
+  rv = ClassicGetThemePartAndState(aFrame, aAppearance, part, state, focused);
+  if (NS_FAILED(rv)) return rv;
+
+  if (AssumeThemePartAndStateAreTransparent(part, state)) {
+    return NS_OK;
+  }
+
+  gfxFloat p2a = gfxFloat(aFrame->PresContext()->AppUnitsPerDevPixel());
+  RECT widgetRect;
+  gfxRect tr(aRect.X(), aRect.Y(), aRect.Width(), aRect.Height()),
+      dr(aDirtyRect.X(), aDirtyRect.Y(), aDirtyRect.Width(),
+         aDirtyRect.Height());
+
+  tr.Scale(1.0 / p2a);
+  dr.Scale(1.0 / p2a);
+
+  gfxWindowsNativeDrawing nativeDrawing(
+      aContext, dr, GetWidgetNativeDrawingFlags(aAppearance));
+
+RENDER_AGAIN:
+
+  HDC hdc = nativeDrawing.BeginNativeDrawing();
+  if (!hdc) return NS_ERROR_FAILURE;
+
+  nativeDrawing.TransformToNativeRect(tr, widgetRect);
+
+  rv = NS_OK;
+  switch (aAppearance) {
+    // Draw button
+    case StyleAppearance::Button: {
+      if (focused) {
+        // draw dark button focus border first
+        if (HBRUSH brush = ::GetSysColorBrush(COLOR_3DDKSHADOW)) {
+          ::FrameRect(hdc, &widgetRect, brush);
+        }
+        InflateRect(&widgetRect, -1, -1);
+      }
+      // setup DC to make DrawFrameControl draw correctly
+      int32_t oldTA = ::SetTextAlign(hdc, TA_TOP | TA_LEFT | TA_NOUPDATECP);
+      ::DrawFrameControl(hdc, &widgetRect, part, state);
+      ::SetTextAlign(hdc, oldTA);
+      break;
+    }
+    // Draw controls with 2px 3D inset border
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Listbox:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton: {
+      // Draw inset edge
+      ::DrawEdge(hdc, &widgetRect, EDGE_SUNKEN, BF_RECT | BF_ADJUST);
+
+      ElementState elementState = GetContentState(aFrame, aAppearance);
+
+      // Fill in background
+
+      if (elementState.HasState(ElementState::DISABLED) ||
+          (aFrame->GetContent()->IsXULElement() && IsReadOnly(aFrame)))
+        ::FillRect(hdc, &widgetRect, (HBRUSH)(COLOR_BTNFACE + 1));
+      else
+        ::FillRect(hdc, &widgetRect, (HBRUSH)(COLOR_WINDOW + 1));
+
+      break;
+    }
+    case StyleAppearance::Treeview: {
+      // Draw inset edge
+      ::DrawEdge(hdc, &widgetRect, EDGE_SUNKEN, BF_RECT | BF_ADJUST);
+
+      // Fill in window color background
+      ::FillRect(hdc, &widgetRect, (HBRUSH)(COLOR_WINDOW + 1));
+
+      break;
+    }
+    // Draw 3D face background controls
+    case StyleAppearance::ProgressBar:
+      // Draw 3D border
+      ::DrawEdge(hdc, &widgetRect, BDR_SUNKENOUTER, BF_RECT | BF_MIDDLE);
+      InflateRect(&widgetRect, -1, -1);
+      [[fallthrough]];
+    case StyleAppearance::Tabpanel: {
+      ::FillRect(hdc, &widgetRect, (HBRUSH)(COLOR_BTNFACE + 1));
+      break;
+    }
+    case StyleAppearance::RangeThumb: {
+      ElementState elementState = GetContentState(aFrame, aAppearance);
+
+      ::DrawEdge(hdc, &widgetRect, EDGE_RAISED,
+                 BF_RECT | BF_SOFT | BF_MIDDLE | BF_ADJUST);
+      if (elementState.HasState(ElementState::DISABLED)) {
+        DrawCheckedRect(hdc, widgetRect, COLOR_3DFACE, COLOR_3DHILIGHT,
+                        (HBRUSH)COLOR_3DHILIGHT);
+      }
+
+      break;
+    }
+    // Draw scale track background
+    case StyleAppearance::Range: {
+      const int32_t trackWidth = 4;
+      // When rounding is necessary, we round the position of the track
+      // away from the chevron of the thumb to make it look better.
+      if (IsRangeHorizontal(aFrame)) {
+        widgetRect.top += (widgetRect.bottom - widgetRect.top - trackWidth) / 2;
+        widgetRect.bottom = widgetRect.top + trackWidth;
+      } else {
+        if (!IsFrameRTL(aFrame)) {
+          widgetRect.left +=
+              (widgetRect.right - widgetRect.left - trackWidth) / 2;
+          widgetRect.right = widgetRect.left + trackWidth;
+        } else {
+          widgetRect.right -=
+              (widgetRect.right - widgetRect.left - trackWidth) / 2;
+          widgetRect.left = widgetRect.right - trackWidth;
+        }
+      }
+
+      ::DrawEdge(hdc, &widgetRect, EDGE_SUNKEN, BF_RECT | BF_ADJUST);
+      ::FillRect(hdc, &widgetRect, (HBRUSH)GetStockObject(GRAY_BRUSH));
+
+      break;
+    }
+    case StyleAppearance::Progresschunk: {
+      nsIFrame* stateFrame = aFrame->GetParent();
+      ElementState elementState = GetContentState(stateFrame, aAppearance);
+
+      const bool indeterminate =
+          elementState.HasState(ElementState::INDETERMINATE);
+      bool vertical = IsVerticalProgress(stateFrame);
+
+      nsIContent* content = aFrame->GetContent();
+      if (!indeterminate || !content) {
+        ::FillRect(hdc, &widgetRect, (HBRUSH)(COLOR_HIGHLIGHT + 1));
+        break;
+      }
+
+      RECT overlayRect = CalculateProgressOverlayRect(
+          aFrame, &widgetRect, vertical, indeterminate, true);
+
+      ::FillRect(hdc, &overlayRect, (HBRUSH)(COLOR_HIGHLIGHT + 1));
+
+      if (!QueueAnimatedContentForRefresh(aFrame->GetContent(), 30)) {
+        NS_WARNING("unable to animate progress widget!");
+      }
+      break;
+    }
+
+    // Draw Tab
+    case StyleAppearance::Tab: {
+      DrawTab(hdc, widgetRect, IsBottomTab(aFrame) ? BF_BOTTOM : BF_TOP,
+              IsSelectedTab(aFrame), !IsRightToSelectedTab(aFrame),
+              !IsLeftToSelectedTab(aFrame));
+
+      break;
+    }
+    case StyleAppearance::Tabpanels:
+      ::DrawEdge(hdc, &widgetRect, EDGE_RAISED,
+                 BF_SOFT | BF_MIDDLE | BF_LEFT | BF_RIGHT | BF_BOTTOM);
+
+      break;
+
+    default:
+      rv = NS_ERROR_FAILURE;
+      break;
+  }
+
+  nativeDrawing.EndNativeDrawing();
+
+  if (NS_FAILED(rv)) return rv;
+
+  if (nativeDrawing.ShouldRenderAgain()) goto RENDER_AGAIN;
+
+  nativeDrawing.PaintToContext();
+
+  return rv;
+}
+
+uint32_t nsNativeThemeWin::GetWidgetNativeDrawingFlags(
+    StyleAppearance aAppearance) {
+  switch (aAppearance) {
+    case StyleAppearance::Button:
+    case StyleAppearance::NumberInput:
+    case StyleAppearance::Textfield:
+    case StyleAppearance::Textarea:
+    case StyleAppearance::Menulist:
+    case StyleAppearance::MenulistButton:
+      return gfxWindowsNativeDrawing::CANNOT_DRAW_TO_COLOR_ALPHA |
+             gfxWindowsNativeDrawing::CAN_AXIS_ALIGNED_SCALE |
+             gfxWindowsNativeDrawing::CANNOT_COMPLEX_TRANSFORM;
+
+    // need to check these others
+    default:
+      return gfxWindowsNativeDrawing::CANNOT_DRAW_TO_COLOR_ALPHA |
+             gfxWindowsNativeDrawing::CANNOT_AXIS_ALIGNED_SCALE |
+             gfxWindowsNativeDrawing::CANNOT_COMPLEX_TRANSFORM;
+  }
+}
+
+}  // namespace mozilla::widget
+
+///////////////////////////////////////////
+// Creation Routine
+///////////////////////////////////////////
+
+already_AddRefed<Theme> do_CreateNativeThemeDoNotUseDirectly() {
+  return do_AddRef(new nsNativeThemeWin());
+}
diff --git a/widget/windows/nsNativeThemeWin.h b/widget/windows/nsNativeThemeWin.h
new file mode 100644
index 0000000000..9937018197
--- /dev/null
+++ b/widget/windows/nsNativeThemeWin.h
@@ -0,0 +1,166 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsNativeThemeWin_h
+#define nsNativeThemeWin_h
+
+#include <windows.h>
+
+#include "mozilla/Maybe.h"
+#include "mozilla/TimeStamp.h"
+#include "Theme.h"
+#include "nsUXThemeConstants.h"
+#include "nsUXThemeData.h"
+
+namespace mozilla::widget {
+
+class nsNativeThemeWin : public Theme {
+ protected:
+  virtual ~nsNativeThemeWin();
+
+ public:
+  // Whether we draw a non-native widget.
+  //
+  // We always draw scrollbars as non-native so that all of Firefox has
+  // consistent scrollbar styles both in chrome and content (plus, the
+  // non-native scrollbars support scrollbar-width, auto-darkening...).
+  //
+  // We draw other widgets as non-native when their color-scheme is dark.  In
+  // that case (`BecauseColorMismatch`) we don't call into the non-native theme
+  // for sizing information (GetWidgetPadding/Border and GetMinimumWidgetSize),
+  // to avoid subtle sizing changes. The non-native theme can basically draw at
+  // any size, so we prefer to have consistent sizing information.
+  enum class NonNative { No, Always, BecauseColorMismatch };
+  static bool IsWidgetAlwaysNonNative(nsIFrame*, StyleAppearance);
+  NonNative IsWidgetNonNative(nsIFrame*, StyleAppearance);
+
+  // The nsITheme interface.
+  NS_IMETHOD DrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
+                                  StyleAppearance aAppearance,
+                                  const nsRect& aRect, const nsRect& aDirtyRect,
+                                  DrawOverflow) override;
+
+  bool CreateWebRenderCommandsForWidget(wr::DisplayListBuilder&,
+                                        wr::IpcResourceUpdateQueue&,
+                                        const layers::StackingContextHelper&,
+                                        layers::RenderRootStateManager*,
+                                        nsIFrame*, StyleAppearance,
+                                        const nsRect&) override;
+
+  [[nodiscard]] LayoutDeviceIntMargin GetWidgetBorder(
+      nsDeviceContext* aContext, nsIFrame* aFrame,
+      StyleAppearance aAppearance) override;
+
+  bool GetWidgetPadding(nsDeviceContext* aContext, nsIFrame* aFrame,
+                        StyleAppearance aAppearance,
+                        LayoutDeviceIntMargin* aResult) override;
+
+  virtual bool GetWidgetOverflow(nsDeviceContext* aContext, nsIFrame* aFrame,
+                                 StyleAppearance aAppearance,
+                                 nsRect* aOverflowRect) override;
+
+  LayoutDeviceIntSize GetMinimumWidgetSize(
+      nsPresContext* aPresContext, nsIFrame* aFrame,
+      StyleAppearance aAppearance) override;
+
+  virtual Transparency GetWidgetTransparency(
+      nsIFrame* aFrame, StyleAppearance aAppearance) override;
+
+  NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, StyleAppearance aAppearance,
+                                nsAtom* aAttribute, bool* aShouldRepaint,
+                                const nsAttrValue* aOldValue) override;
+
+  NS_IMETHOD ThemeChanged() override;
+
+  bool ThemeSupportsWidget(nsPresContext* aPresContext, nsIFrame* aFrame,
+                           StyleAppearance aAppearance) override;
+
+  bool ThemeDrawsFocusForWidget(nsIFrame*, StyleAppearance) override;
+
+  bool ThemeWantsButtonInnerFocusRing() override { return true; }
+
+  bool ThemeNeedsComboboxDropmarker() override;
+
+  nsNativeThemeWin();
+
+ protected:
+  Maybe<nsUXThemeClass> GetThemeClass(StyleAppearance aAppearance);
+  HANDLE GetTheme(StyleAppearance aAppearance);
+  nsresult GetThemePartAndState(nsIFrame* aFrame, StyleAppearance aAppearance,
+                                int32_t& aPart, int32_t& aState);
+  nsresult ClassicGetThemePartAndState(nsIFrame* aFrame,
+                                       StyleAppearance aAppearance,
+                                       int32_t& aPart, int32_t& aState,
+                                       bool& aFocused);
+  nsresult ClassicDrawWidgetBackground(gfxContext* aContext, nsIFrame* aFrame,
+                                       StyleAppearance aAppearance,
+                                       const nsRect& aRect,
+                                       const nsRect& aClipRect);
+  [[nodiscard]] LayoutDeviceIntMargin ClassicGetWidgetBorder(
+      nsDeviceContext* aContext, nsIFrame* aFrame, StyleAppearance aAppearance);
+  bool ClassicGetWidgetPadding(nsDeviceContext* aContext, nsIFrame* aFrame,
+                               StyleAppearance aAppearance,
+                               LayoutDeviceIntMargin* aResult);
+  LayoutDeviceIntSize ClassicGetMinimumWidgetSize(nsIFrame* aFrame,
+                                                  StyleAppearance aAppearance);
+  bool ClassicThemeSupportsWidget(nsIFrame* aFrame,
+                                  StyleAppearance aAppearance);
+  void DrawCheckedRect(HDC hdc, const RECT& rc, int32_t fore, int32_t back,
+                       HBRUSH defaultBack);
+  uint32_t GetWidgetNativeDrawingFlags(StyleAppearance aAppearance);
+  int32_t StandardGetState(nsIFrame* aFrame, StyleAppearance aAppearance,
+                           bool wantFocused);
+  bool IsMenuActive(nsIFrame* aFrame, StyleAppearance aAppearance);
+  RECT CalculateProgressOverlayRect(nsIFrame* aFrame, RECT* aWidgetRect,
+                                    bool aIsVertical, bool aIsIndeterminate,
+                                    bool aIsClassic);
+  void DrawThemedProgressMeter(nsIFrame* aFrame, StyleAppearance aAppearance,
+                               HANDLE aTheme, HDC aHdc, int aPart, int aState,
+                               RECT* aWidgetRect, RECT* aClipRect);
+
+  [[nodiscard]] LayoutDeviceIntMargin GetCachedWidgetBorder(
+      HANDLE aTheme, nsUXThemeClass aThemeClass, StyleAppearance aAppearance,
+      int32_t aPart, int32_t aState);
+
+  nsresult GetCachedMinimumWidgetSize(nsIFrame* aFrame, HANDLE aTheme,
+                                      nsUXThemeClass aThemeClass,
+                                      StyleAppearance aAppearance,
+                                      int32_t aPart, int32_t aState,
+                                      THEMESIZE aSizeReq,
+                                      LayoutDeviceIntSize* aResult);
+
+  SIZE GetCachedGutterSize(HANDLE theme);
+
+ private:
+  TimeStamp mProgressDeterminateTimeStamp;
+  TimeStamp mProgressIndeterminateTimeStamp;
+
+  // eUXNumClasses * THEME_PART_DISTINCT_VALUE_COUNT is about 800 at the time of
+  // writing this, and nsIntMargin is 16 bytes wide, which makes this cache (1/8
+  // + 16) * 800 bytes, or about ~12KB. We could probably reduce this cache to
+  // 3KB by caching on the aAppearance value instead, but there would be some
+  // uncacheable values, since we derive some theme parts from other arguments.
+  uint8_t
+      mBorderCacheValid[(eUXNumClasses * THEME_PART_DISTINCT_VALUE_COUNT + 7) /
+                        8];
+  LayoutDeviceIntMargin
+      mBorderCache[eUXNumClasses * THEME_PART_DISTINCT_VALUE_COUNT];
+
+  // See the above not for mBorderCache and friends. However
+  // LayoutDeviceIntSize is half the size of nsIntMargin, making the
+  // cache roughly half as large. In total the caches should come to about 18KB.
+  uint8_t mMinimumWidgetSizeCacheValid
+      [(eUXNumClasses * THEME_PART_DISTINCT_VALUE_COUNT + 7) / 8];
+  LayoutDeviceIntSize
+      mMinimumWidgetSizeCache[eUXNumClasses * THEME_PART_DISTINCT_VALUE_COUNT];
+
+  bool mGutterSizeCacheValid;
+  SIZE mGutterSizeCache;
+};
+
+}  // namespace mozilla::widget
+
+#endif
diff --git a/widget/windows/nsPrintDialogUtil.cpp b/widget/windows/nsPrintDialogUtil.cpp
new file mode 100644
index 0000000000..43f56e9706
--- /dev/null
+++ b/widget/windows/nsPrintDialogUtil.cpp
@@ -0,0 +1,360 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* -------------------------------------------------------------------
+To Build This:
+
+  You need to add this to the the makefile.win in mozilla/dom/base:
+
+        .\$(OBJDIR)\nsFlyOwnPrintDialog.obj	\
+
+
+  And this to the makefile.win in mozilla/content/build:
+
+WIN_LIBS=                                       \
+        winspool.lib                           \
+        comctl32.lib                           \
+        comdlg32.lib
+
+---------------------------------------------------------------------- */
+
+#include <windows.h>
+#include <tchar.h>
+
+#include <unknwn.h>
+#include <commdlg.h>
+
+#include "mozilla/BackgroundHangMonitor.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/Span.h"
+#include "nsString.h"
+#include "nsReadableUtils.h"
+#include "nsIPrintSettings.h"
+#include "nsIPrintSettingsWin.h"
+#include "nsIPrinterList.h"
+#include "nsServiceManagerUtils.h"
+
+#include "nsRect.h"
+
+#include "nsCRT.h"
+#include "prenv.h" /* for PR_GetEnv */
+
+#include <windows.h>
+#include <winspool.h>
+
+// For Localization
+
+// For NS_CopyUnicodeToNative
+#include "nsNativeCharsetUtils.h"
+
+// This is for extending the dialog
+#include <dlgs.h>
+
+#include "nsWindowsHelpers.h"
+#include "WinUtils.h"
+
+//-----------------------------------------------
+// Global Data
+//-----------------------------------------------
+
+static HWND gParentWnd = nullptr;
+
+//----------------------------------------------------------------------------------
+// Returns a Global Moveable Memory Handle to a DevMode
+// from the Printer by the name of aPrintName
+//
+// NOTE:
+//   This function assumes that aPrintName has already been converted from
+//   unicode
+//
+static nsReturnRef<nsHGLOBAL> CreateGlobalDevModeAndInit(
+    const nsString& aPrintName, nsIPrintSettings* aPS) {
+  nsHPRINTER hPrinter = nullptr;
+  // const cast kludge for silly Win32 api's
+  LPWSTR printName =
+      const_cast<wchar_t*>(static_cast<const wchar_t*>(aPrintName.get()));
+  BOOL status = ::OpenPrinterW(printName, &hPrinter, nullptr);
+  if (!status) {
+    return nsReturnRef<nsHGLOBAL>();
+  }
+
+  // Make sure hPrinter is closed on all paths
+  nsAutoPrinter autoPrinter(hPrinter);
+
+  // Get the buffer size
+  LONG needed = ::DocumentPropertiesW(gParentWnd, hPrinter, printName, nullptr,
+                                      nullptr, 0);
+  if (needed < 0) {
+    return nsReturnRef<nsHGLOBAL>();
+  }
+
+  // Some drivers do not return the correct size for their DEVMODE, so we
+  // over-allocate to try and compensate.
+  // (See https://bugzilla.mozilla.org/show_bug.cgi?id=1664530#c5)
+  needed *= 2;
+  nsAutoDevMode newDevMode(
+      (LPDEVMODEW)::HeapAlloc(::GetProcessHeap(), HEAP_ZERO_MEMORY, needed));
+  if (!newDevMode) {
+    return nsReturnRef<nsHGLOBAL>();
+  }
+
+  nsHGLOBAL hDevMode = ::GlobalAlloc(GHND, needed);
+  nsAutoGlobalMem globalDevMode(hDevMode);
+  if (!hDevMode) {
+    return nsReturnRef<nsHGLOBAL>();
+  }
+
+  LONG ret = ::DocumentPropertiesW(gParentWnd, hPrinter, printName, newDevMode,
+                                   nullptr, DM_OUT_BUFFER);
+  if (ret != IDOK) {
+    return nsReturnRef<nsHGLOBAL>();
+  }
+
+  // Lock memory and copy contents from DEVMODE (current printer)
+  // to Global Memory DEVMODE
+  LPDEVMODEW devMode = (DEVMODEW*)::GlobalLock(hDevMode);
+  if (!devMode) {
+    return nsReturnRef<nsHGLOBAL>();
+  }
+
+  memcpy(devMode, newDevMode.get(), needed);
+  // Initialize values from the PrintSettings
+  nsCOMPtr<nsIPrintSettingsWin> psWin = do_QueryInterface(aPS);
+  MOZ_ASSERT(psWin);
+  psWin->CopyToNative(devMode);
+
+  // Sets back the changes we made to the DevMode into the Printer Driver
+  ret = ::DocumentPropertiesW(gParentWnd, hPrinter, printName, devMode, devMode,
+                              DM_IN_BUFFER | DM_OUT_BUFFER);
+  if (ret != IDOK) {
+    ::GlobalUnlock(hDevMode);
+    return nsReturnRef<nsHGLOBAL>();
+  }
+
+  ::GlobalUnlock(hDevMode);
+
+  return globalDevMode.out();
+}
+
+//------------------------------------------------------------------
+// helper
+static void GetDefaultPrinterNameFromGlobalPrinters(nsAString& aPrinterName) {
+  aPrinterName.Truncate();
+  nsCOMPtr<nsIPrinterList> printerList =
+      do_GetService("@mozilla.org/gfx/printerlist;1");
+  if (printerList) {
+    printerList->GetSystemDefaultPrinterName(aPrinterName);
+  }
+}
+
+//------------------------------------------------------------------
+// Displays the native Print Dialog
+nsresult NativeShowPrintDialog(HWND aHWnd, bool aHaveSelection,
+                               nsIPrintSettings* aPrintSettings) {
+  // NS_ENSURE_ARG_POINTER(aHWnd);
+  NS_ENSURE_ARG_POINTER(aPrintSettings);
+
+  // Get the Print Name to be used
+  nsString printerName;
+  aPrintSettings->GetPrinterName(printerName);
+
+  // If there is no name then use the default printer
+  if (printerName.IsEmpty()) {
+    GetDefaultPrinterNameFromGlobalPrinters(printerName);
+  } else {
+    HANDLE hPrinter = nullptr;
+    if (!::OpenPrinterW(const_cast<wchar_t*>(
+                            static_cast<const wchar_t*>(printerName.get())),
+                        &hPrinter, nullptr)) {
+      // If the last used printer is not found, we should use default printer.
+      GetDefaultPrinterNameFromGlobalPrinters(printerName);
+    } else {
+      ::ClosePrinter(hPrinter);
+    }
+  }
+
+  // Now create a DEVNAMES struct so the the dialog is initialized correctly.
+
+  uint32_t len = printerName.Length();
+  nsHGLOBAL hDevNames =
+      ::GlobalAlloc(GHND, sizeof(wchar_t) * (len + 1) + sizeof(DEVNAMES));
+  nsAutoGlobalMem autoDevNames(hDevNames);
+  if (!hDevNames) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  DEVNAMES* pDevNames = (DEVNAMES*)::GlobalLock(hDevNames);
+  if (!pDevNames) {
+    return NS_ERROR_FAILURE;
+  }
+  pDevNames->wDriverOffset = sizeof(DEVNAMES) / sizeof(wchar_t);
+  pDevNames->wDeviceOffset = sizeof(DEVNAMES) / sizeof(wchar_t);
+  pDevNames->wOutputOffset = sizeof(DEVNAMES) / sizeof(wchar_t) + len;
+  pDevNames->wDefault = 0;
+
+  memcpy(pDevNames + 1, printerName.get(), (len + 1) * sizeof(wchar_t));
+  ::GlobalUnlock(hDevNames);
+
+  // Create a Moveable Memory Object that holds a new DevMode
+  // from the Printer Name
+  // The PRINTDLG.hDevMode requires that it be a moveable memory object
+  // NOTE: autoDevMode is automatically freed when any error occurred
+  nsAutoGlobalMem autoDevMode(
+      CreateGlobalDevModeAndInit(printerName, aPrintSettings));
+
+  // Prepare to Display the Print Dialog
+  // https://docs.microsoft.com/en-us/previous-versions/windows/desktop/legacy/ms646942(v=vs.85)
+  // https://docs.microsoft.com/en-us/windows/win32/api/commdlg/ns-commdlg-printdlgexw
+  PRINTDLGEXW prntdlg;
+  memset(&prntdlg, 0, sizeof(prntdlg));
+
+  prntdlg.lStructSize = sizeof(prntdlg);
+  prntdlg.hwndOwner = aHWnd;
+  prntdlg.hDevMode = autoDevMode.get();
+  prntdlg.hDevNames = hDevNames;
+  prntdlg.hDC = nullptr;
+  prntdlg.Flags = PD_ALLPAGES | PD_RETURNIC | PD_USEDEVMODECOPIESANDCOLLATE |
+                  PD_COLLATE | PD_NOCURRENTPAGE;
+
+  // If there is a current selection then enable the "Selection" radio button
+  if (!aHaveSelection) {
+    prntdlg.Flags |= PD_NOSELECTION;
+  }
+
+  // 10 seems like a reasonable max number of ranges to support by default if
+  // the user doesn't choose a greater thing in the UI.
+  constexpr size_t kMinSupportedRanges = 10;
+
+  AutoTArray<PRINTPAGERANGE, kMinSupportedRanges> winPageRanges;
+  // Set up the page ranges.
+  {
+    AutoTArray<int32_t, kMinSupportedRanges * 2> pageRanges;
+    aPrintSettings->GetPageRanges(pageRanges);
+    // If there is a specified page range then enable the "Custom" radio button
+    if (!pageRanges.IsEmpty()) {
+      prntdlg.Flags |= PD_PAGENUMS;
+    }
+
+    const size_t specifiedRanges = pageRanges.Length() / 2;
+    const size_t maxRanges = std::max(kMinSupportedRanges, specifiedRanges);
+
+    prntdlg.nMaxPageRanges = maxRanges;
+    prntdlg.nPageRanges = specifiedRanges;
+
+    winPageRanges.SetCapacity(maxRanges);
+    for (size_t i = 0; i < pageRanges.Length(); i += 2) {
+      PRINTPAGERANGE* range = winPageRanges.AppendElement();
+      range->nFromPage = pageRanges[i];
+      range->nToPage = pageRanges[i + 1];
+    }
+    prntdlg.lpPageRanges = winPageRanges.Elements();
+
+    prntdlg.nMinPage = 1;
+    // TODO(emilio): Could probably get the right page number here from the
+    // new print UI.
+    prntdlg.nMaxPage = 0xFFFF;
+  }
+
+  // NOTE(emilio): This can always be 1 because we use the DEVMODE copies
+  // feature (see PD_USEDEVMODECOPIESANDCOLLATE).
+  prntdlg.nCopies = 1;
+
+  prntdlg.hInstance = nullptr;
+  prntdlg.lpPrintTemplateName = nullptr;
+
+  prntdlg.lpCallback = nullptr;
+  prntdlg.nPropertyPages = 0;
+  prntdlg.lphPropertyPages = nullptr;
+
+  prntdlg.nStartPage = START_PAGE_GENERAL;
+  prntdlg.dwResultAction = 0;
+
+  HRESULT result;
+  {
+    mozilla::widget::WinUtils::AutoSystemDpiAware dpiAwareness;
+    mozilla::BackgroundHangMonitor().NotifyWait();
+    result = ::PrintDlgExW(&prntdlg);
+  }
+
+  auto cancelOnExit = mozilla::MakeScopeExit([&] { ::SetFocus(aHWnd); });
+
+  if (NS_WARN_IF(!SUCCEEDED(result))) {
+#ifdef DEBUG
+    printf_stderr("PrintDlgExW failed with %lx\n", result);
+#endif
+    return NS_ERROR_FAILURE;
+  }
+  if (NS_WARN_IF(prntdlg.dwResultAction != PD_RESULT_PRINT)) {
+    return NS_ERROR_ABORT;
+  }
+  // check to make sure we don't have any nullptr pointers
+  NS_ENSURE_TRUE(prntdlg.hDevMode, NS_ERROR_ABORT);
+  NS_ENSURE_TRUE(prntdlg.hDevNames, NS_ERROR_ABORT);
+  // Lock the deviceNames and check for nullptr
+  DEVNAMES* devnames = (DEVNAMES*)::GlobalLock(prntdlg.hDevNames);
+  NS_ENSURE_TRUE(devnames, NS_ERROR_ABORT);
+
+  char16_t* device = &(((char16_t*)devnames)[devnames->wDeviceOffset]);
+  char16_t* driver = &(((char16_t*)devnames)[devnames->wDriverOffset]);
+
+  // Check to see if the "Print To File" control is checked
+  // then take the name from devNames and set it in the PrintSettings
+  //
+  // NOTE:
+  // As per Microsoft SDK documentation the returned value offset from
+  // devnames->wOutputOffset is either "FILE:" or nullptr
+  // if the "Print To File" checkbox is checked it MUST be "FILE:"
+  // We assert as an extra safety check.
+  if (prntdlg.Flags & PD_PRINTTOFILE) {
+    char16ptr_t fileName = &(((wchar_t*)devnames)[devnames->wOutputOffset]);
+    NS_ASSERTION(wcscmp(fileName, L"FILE:") == 0, "FileName must be `FILE:`");
+    aPrintSettings->SetOutputDestination(
+        nsIPrintSettings::kOutputDestinationFile);
+    aPrintSettings->SetToFileName(nsDependentString(fileName));
+  } else {
+    // clear "print to file" info
+    aPrintSettings->SetOutputDestination(
+        nsIPrintSettings::kOutputDestinationPrinter);
+    aPrintSettings->SetToFileName(u""_ns);
+  }
+
+  nsCOMPtr<nsIPrintSettingsWin> psWin(do_QueryInterface(aPrintSettings));
+  MOZ_RELEASE_ASSERT(psWin);
+
+  // Setup local Data members
+  psWin->SetDeviceName(nsDependentString(device));
+  psWin->SetDriverName(nsDependentString(driver));
+
+  // Fill the print options with the info from the dialog
+  aPrintSettings->SetPrinterName(nsDependentString(device));
+  aPrintSettings->SetPrintSelectionOnly(prntdlg.Flags & PD_SELECTION);
+
+  AutoTArray<int32_t, kMinSupportedRanges * 2> pageRanges;
+  if (prntdlg.Flags & PD_PAGENUMS) {
+    pageRanges.SetCapacity(prntdlg.nPageRanges * 2);
+    for (const auto& range :
+         mozilla::Span(prntdlg.lpPageRanges, prntdlg.nPageRanges)) {
+      pageRanges.AppendElement(range.nFromPage);
+      pageRanges.AppendElement(range.nToPage);
+    }
+  }
+  aPrintSettings->SetPageRanges(pageRanges);
+
+  // Unlock DeviceNames
+  ::GlobalUnlock(prntdlg.hDevNames);
+
+  // Transfer the settings from the native data to the PrintSettings
+  LPDEVMODEW devMode = (LPDEVMODEW)::GlobalLock(prntdlg.hDevMode);
+  if (!devMode || !prntdlg.hDC) {
+    return NS_ERROR_FAILURE;
+  }
+  psWin->SetDevMode(devMode);  // copies DevMode
+  psWin->CopyFromNative(prntdlg.hDC, devMode);
+  ::GlobalUnlock(prntdlg.hDevMode);
+  ::DeleteDC(prntdlg.hDC);
+
+  cancelOnExit.release();
+  return NS_OK;
+}
diff --git a/widget/windows/nsPrintDialogUtil.h b/widget/windows/nsPrintDialogUtil.h
new file mode 100644
index 0000000000..3ec16e1b1d
--- /dev/null
+++ b/widget/windows/nsPrintDialogUtil.h
@@ -0,0 +1,11 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef nsFlyOwnDialog_h___
+#define nsFlyOwnDialog_h___
+
+nsresult NativeShowPrintDialog(HWND aHWnd, bool aHaveSelection,
+                               nsIPrintSettings* aPrintSettings);
+
+#endif /* nsFlyOwnDialog_h___ */
diff --git a/widget/windows/nsPrintDialogWin.cpp b/widget/windows/nsPrintDialogWin.cpp
new file mode 100644
index 0000000000..35ea52b17b
--- /dev/null
+++ b/widget/windows/nsPrintDialogWin.cpp
@@ -0,0 +1,147 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrintDialogWin.h"
+
+#include "nsArray.h"
+#include "nsComponentManagerUtils.h"
+#include "nsCOMPtr.h"
+#include "nsIBaseWindow.h"
+#include "nsIBrowserChild.h"
+#include "nsIDialogParamBlock.h"
+#include "nsIDocShell.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsIPrintSettings.h"
+#include "nsIWebBrowserChrome.h"
+#include "nsIWidget.h"
+#include "nsPrintDialogUtil.h"
+#include "nsIPrintSettings.h"
+#include "nsIWebBrowserChrome.h"
+#include "nsServiceManagerUtils.h"
+#include "nsPIDOMWindow.h"
+#include "nsQueryObject.h"
+#include "WidgetUtils.h"
+#include "WinUtils.h"
+
+static const char* kPageSetupDialogURL =
+    "chrome://global/content/printPageSetup.xhtml";
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+/**
+ * ParamBlock
+ */
+
+class ParamBlock {
+ public:
+  ParamBlock() { mBlock = 0; }
+  ~ParamBlock() { NS_IF_RELEASE(mBlock); }
+  nsresult Init() {
+    return CallCreateInstance(NS_DIALOGPARAMBLOCK_CONTRACTID, &mBlock);
+  }
+  nsIDialogParamBlock* operator->() const MOZ_NO_ADDREF_RELEASE_ON_RETURN {
+    return mBlock;
+  }
+  operator nsIDialogParamBlock* const() { return mBlock; }
+
+ private:
+  nsIDialogParamBlock* mBlock;
+};
+
+NS_IMPL_ISUPPORTS(nsPrintDialogServiceWin, nsIPrintDialogService)
+
+nsPrintDialogServiceWin::nsPrintDialogServiceWin() {}
+
+nsPrintDialogServiceWin::~nsPrintDialogServiceWin() {}
+
+NS_IMETHODIMP
+nsPrintDialogServiceWin::Init() {
+  nsresult rv;
+  mWatcher = do_GetService(NS_WINDOWWATCHER_CONTRACTID, &rv);
+  return rv;
+}
+
+NS_IMETHODIMP
+nsPrintDialogServiceWin::ShowPrintDialog(mozIDOMWindowProxy* aParent,
+                                         bool aHaveSelection,
+                                         nsIPrintSettings* aSettings) {
+  NS_ENSURE_ARG(aParent);
+  RefPtr<nsIWidget> parentWidget =
+      WidgetUtils::DOMWindowToWidget(nsPIDOMWindowOuter::From(aParent));
+
+  ScopedRtlShimWindow shim(parentWidget.get());
+  NS_ASSERTION(shim.get(), "Couldn't get native window for PRint Dialog!");
+
+  return NativeShowPrintDialog(shim.get(), aHaveSelection, aSettings);
+}
+
+NS_IMETHODIMP
+nsPrintDialogServiceWin::ShowPageSetupDialog(mozIDOMWindowProxy* aParent,
+                                             nsIPrintSettings* aNSSettings) {
+  NS_ENSURE_ARG(aParent);
+  NS_ENSURE_ARG(aNSSettings);
+
+  ParamBlock block;
+  nsresult rv = block.Init();
+  if (NS_FAILED(rv)) return rv;
+
+  block->SetInt(0, 0);
+  rv = DoDialog(aParent, block, aNSSettings, kPageSetupDialogURL);
+
+  // if aWebBrowserPrint is not null then we are printing
+  // so we want to pass back NS_ERROR_ABORT on cancel
+  if (NS_SUCCEEDED(rv)) {
+    int32_t status;
+    block->GetInt(0, &status);
+    return status == 0 ? NS_ERROR_ABORT : NS_OK;
+  }
+
+  // We don't call nsPrintSettingsService::MaybeSavePrintSettingsToPrefs here
+  // since it's called for us in printPageSetup.js.  Maybe we should move that
+  // call here for consistency with the other platforms though?
+
+  return rv;
+}
+
+nsresult nsPrintDialogServiceWin::DoDialog(mozIDOMWindowProxy* aParent,
+                                           nsIDialogParamBlock* aParamBlock,
+                                           nsIPrintSettings* aPS,
+                                           const char* aChromeURL) {
+  NS_ENSURE_ARG(aParamBlock);
+  NS_ENSURE_ARG(aPS);
+  NS_ENSURE_ARG(aChromeURL);
+
+  if (!mWatcher) return NS_ERROR_FAILURE;
+
+  // get a parent, if at all possible
+  // (though we'd rather this didn't fail, it's OK if it does. so there's
+  // no failure or null check.)
+  // retain ownership for method lifetime
+  nsCOMPtr<mozIDOMWindowProxy> activeParent;
+  if (!aParent) {
+    mWatcher->GetActiveWindow(getter_AddRefs(activeParent));
+    aParent = activeParent;
+  }
+
+  // create a nsIMutableArray of the parameters
+  // being passed to the window
+  nsCOMPtr<nsIMutableArray> array = nsArray::Create();
+
+  nsCOMPtr<nsISupports> psSupports(do_QueryInterface(aPS));
+  NS_ASSERTION(psSupports, "PrintSettings must be a supports");
+  array->AppendElement(psSupports);
+
+  nsCOMPtr<nsISupports> blkSupps(do_QueryInterface(aParamBlock));
+  NS_ASSERTION(blkSupps, "IOBlk must be a supports");
+  array->AppendElement(blkSupps);
+
+  nsCOMPtr<mozIDOMWindowProxy> dialog;
+  nsresult rv = mWatcher->OpenWindow(
+      aParent, nsDependentCString(aChromeURL), "_blank"_ns,
+      "centerscreen,chrome,modal,titlebar"_ns, array, getter_AddRefs(dialog));
+
+  return rv;
+}
diff --git a/widget/windows/nsPrintDialogWin.h b/widget/windows/nsPrintDialogWin.h
new file mode 100644
index 0000000000..bb8f212eb5
--- /dev/null
+++ b/widget/windows/nsPrintDialogWin.h
@@ -0,0 +1,39 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrintDialog_h__
+#define nsPrintDialog_h__
+
+#include "nsIPrintDialogService.h"
+
+#include "nsCOMPtr.h"
+#include "nsIWindowWatcher.h"
+
+#include <windef.h>
+
+class nsIPrintSettings;
+class nsIDialogParamBlock;
+
+class nsPrintDialogServiceWin final : public nsIPrintDialogService {
+ public:
+  nsPrintDialogServiceWin();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIPRINTDIALOGSERVICE
+
+ private:
+  virtual ~nsPrintDialogServiceWin();
+
+  nsresult DoDialog(mozIDOMWindowProxy* aParent,
+                    nsIDialogParamBlock* aParamBlock, nsIPrintSettings* aPS,
+                    const char* aChromeURL);
+
+  nsCOMPtr<nsIWindowWatcher> mWatcher;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsPrintDialogServiceWin,
+                              NS_IPRINTDIALOGSERVICE_IID)
+
+#endif
diff --git a/widget/windows/nsPrintSettingsServiceWin.cpp b/widget/windows/nsPrintSettingsServiceWin.cpp
new file mode 100644
index 0000000000..cbc99441ab
--- /dev/null
+++ b/widget/windows/nsPrintSettingsServiceWin.cpp
@@ -0,0 +1,127 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrintSettingsServiceWin.h"
+
+#include "nsCOMPtr.h"
+#include "nsPrintSettingsWin.h"
+#include "nsPrintDialogUtil.h"
+
+#include "nsGfxCIID.h"
+#include "nsIServiceManager.h"
+#include "nsWindowsHelpers.h"
+#include "ipc/IPCMessageUtils.h"
+#include "chrome/common/ipc_channel.h"
+#include "mozilla/embedding/PPrintingTypes.h"
+
+using namespace mozilla::embedding;
+
+NS_IMETHODIMP
+nsPrintSettingsServiceWin::SerializeToPrintData(nsIPrintSettings* aSettings,
+                                                PrintData* data) {
+  nsresult rv = nsPrintSettingsService::SerializeToPrintData(aSettings, data);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIPrintSettingsWin> psWin = do_QueryInterface(aSettings);
+  if (!psWin) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsAutoString deviceName;
+  nsAutoString driverName;
+
+  psWin->GetDeviceName(deviceName);
+  psWin->GetDriverName(driverName);
+
+  data->deviceName().Assign(deviceName);
+  data->driverName().Assign(driverName);
+
+  // When creating the print dialog on Windows, we only need to send certain
+  // print settings information from the parent to the child not vice versa.
+  if (XRE_IsParentProcess()) {
+    // A DEVMODE can actually be of arbitrary size. If it turns out that it'll
+    // make our IPC message larger than the limit, then we'll error out.
+    LPDEVMODEW devModeRaw;
+    psWin->GetDevMode(&devModeRaw);  // This actually allocates a copy of the
+                                     // the nsIPrintSettingsWin DEVMODE, so
+                                     // we're now responsible for deallocating
+                                     // it. We'll use an nsAutoDevMode helper
+                                     // to do this.
+    if (devModeRaw) {
+      nsAutoDevMode devMode(devModeRaw);
+      devModeRaw = nullptr;
+
+      size_t devModeTotalSize = devMode->dmSize + devMode->dmDriverExtra;
+      size_t msgTotalSize = sizeof(PrintData) + devModeTotalSize;
+
+      if (msgTotalSize > IPC::Channel::kMaximumMessageSize / 2) {
+        return NS_ERROR_FAILURE;
+      }
+
+      // Instead of reaching in and manually reading each member, we'll just
+      // copy the bits over.
+      const char* devModeData = reinterpret_cast<const char*>(devMode.get());
+      nsTArray<uint8_t> arrayBuf;
+      arrayBuf.AppendElements(devModeData, devModeTotalSize);
+      data->devModeData() = std::move(arrayBuf);
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrintSettingsServiceWin::DeserializeToPrintSettings(
+    const PrintData& data, nsIPrintSettings* settings) {
+  nsresult rv =
+      nsPrintSettingsService::DeserializeToPrintSettings(data, settings);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIPrintSettingsWin> psWin = do_QueryInterface(settings);
+  if (!settings) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (XRE_IsContentProcess()) {
+    psWin->SetDeviceName(data.deviceName());
+    psWin->SetDriverName(data.driverName());
+
+    if (data.devModeData().IsEmpty()) {
+      psWin->SetDevMode(nullptr);
+    } else {
+      // Check minimum length of DEVMODE data.
+      auto devModeDataLength = data.devModeData().Length();
+      if (devModeDataLength < sizeof(DEVMODEW)) {
+        NS_WARNING("DEVMODE data is too short.");
+        return NS_ERROR_FAILURE;
+      }
+
+      DEVMODEW* devMode = reinterpret_cast<DEVMODEW*>(
+          const_cast<uint8_t*>(data.devModeData().Elements()));
+
+      // Check actual length of DEVMODE data.
+      if ((devMode->dmSize + devMode->dmDriverExtra) != devModeDataLength) {
+        NS_WARNING("DEVMODE length is incorrect.");
+        return NS_ERROR_FAILURE;
+      }
+
+      psWin->SetDevMode(devMode);  // Copies
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult nsPrintSettingsServiceWin::_CreatePrintSettings(
+    nsIPrintSettings** _retval) {
+  *_retval = nullptr;
+  nsPrintSettingsWin* printSettings =
+      new nsPrintSettingsWin();  // does not initially ref count
+  NS_ENSURE_TRUE(printSettings, NS_ERROR_OUT_OF_MEMORY);
+
+  NS_ADDREF(*_retval = printSettings);  // ref count
+
+  return NS_OK;
+}
diff --git a/widget/windows/nsPrintSettingsServiceWin.h b/widget/windows/nsPrintSettingsServiceWin.h
new file mode 100644
index 0000000000..e11d307a8b
--- /dev/null
+++ b/widget/windows/nsPrintSettingsServiceWin.h
@@ -0,0 +1,29 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrintSettingsServiceWin_h
+#define nsPrintSettingsServiceWin_h
+
+#include "nsPrintSettingsService.h"
+
+class nsIPrintSettings;
+
+class nsPrintSettingsServiceWin final : public nsPrintSettingsService {
+ public:
+  nsPrintSettingsServiceWin() {}
+
+  NS_IMETHODIMP SerializeToPrintData(
+      nsIPrintSettings* aSettings,
+      mozilla::embedding::PrintData* data) override;
+
+  NS_IMETHODIMP DeserializeToPrintSettings(
+      const mozilla::embedding::PrintData& data,
+      nsIPrintSettings* settings) override;
+
+  nsresult _CreatePrintSettings(nsIPrintSettings** _retval) override;
+};
+
+#endif  // nsPrintSettingsServiceWin_h
diff --git a/widget/windows/nsPrintSettingsWin.cpp b/widget/windows/nsPrintSettingsWin.cpp
new file mode 100644
index 0000000000..788c4ab6da
--- /dev/null
+++ b/widget/windows/nsPrintSettingsWin.cpp
@@ -0,0 +1,477 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "nsPrintSettingsWin.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "nsCRT.h"
+#include "nsDeviceContextSpecWin.h"
+#include "nsPrintSettingsImpl.h"
+#include "WinUtils.h"
+
+using namespace mozilla;
+
+// Using paper sizes from wingdi.h and the units given there, plus a little
+// extra research for the ones it doesn't give. Looks like the list hasn't
+// changed since Windows 2000, so should be fairly stable now.
+const short kPaperSizeUnits[] = {
+    nsIPrintSettings::kPaperSizeMillimeters,  // Not Used default to mm as
+                                              // DEVMODE uses tenths of mm, just
+                                              // in case
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_LETTER
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_LETTERSMALL
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_TABLOID
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_LEDGER
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_LEGAL
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_STATEMENT
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_EXECUTIVE
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A3
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A4
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A4SMALL
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A5
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_B4
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_B5
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_FOLIO
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_QUARTO
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_10X14
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_11X17
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_NOTE
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_ENV_9
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_ENV_10
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_ENV_11
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_ENV_12
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_ENV_14
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_CSHEET
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_DSHEET
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_ESHEET
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ENV_DL
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ENV_C5
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ENV_C3
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ENV_C4
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ENV_C6
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ENV_C65
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ENV_B4
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ENV_B5
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ENV_B6
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ENV_ITALY
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_ENV_MONARCH
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_ENV_PERSONAL
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_FANFOLD_US
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_FANFOLD_STD_GERMAN
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_FANFOLD_LGL_GERMAN
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ISO_B4
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_JAPANESE_POSTCARD
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_9X11
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_10X11
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_15X11
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_ENV_INVITE
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_RESERVED_48
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_RESERVED_49
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_LETTER_EXTRA
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_LEGAL_EXTRA
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_TABLOID_EXTRA
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_A4_EXTRA
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_LETTER_TRANSVERSE
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A4_TRANSVERSE
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_LETTER_EXTRA_TRANSVERSE
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A_PLUS
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_B_PLUS
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_LETTER_PLUS
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A4_PLUS
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A5_TRANSVERSE
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_B5_TRANSVERSE
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A3_EXTRA
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A5_EXTRA
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_B5_EXTRA
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A2
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A3_TRANSVERSE
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A3_EXTRA_TRANSVERSE
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_DBL_JAPANESE_POSTCARD
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A6
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_JENV_KAKU2
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_JENV_KAKU3
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_JENV_CHOU3
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_JENV_CHOU4
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_LETTER_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A3_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A4_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A5_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_B4_JIS_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_B5_JIS_ROTATED
+    nsIPrintSettings::
+        kPaperSizeMillimeters,  // DMPAPER_JAPANESE_POSTCARD_ROTATED
+    nsIPrintSettings::
+        kPaperSizeMillimeters,  // DMPAPER_DBL_JAPANESE_POSTCARD_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_A6_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_JENV_KAKU2_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_JENV_KAKU3_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_JENV_CHOU3_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_JENV_CHOU4_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_B6_JIS
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_B6_JIS_ROTATED
+    nsIPrintSettings::kPaperSizeInches,       // DMPAPER_12X11
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_JENV_YOU4
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_JENV_YOU4_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_P16K
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_P32K
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_P32KBIG
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_1
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_2
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_3
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_4
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_5
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_6
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_7
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_8
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_9
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_10
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_P16K_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_P32K_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_P32KBIG_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_1_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_2_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_3_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_4_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_5_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_6_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_7_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_8_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_9_ROTATED
+    nsIPrintSettings::kPaperSizeMillimeters,  // DMPAPER_PENV_10_ROTATED
+};
+
+NS_IMPL_ISUPPORTS_INHERITED(nsPrintSettingsWin, nsPrintSettings,
+                            nsIPrintSettingsWin)
+
+/** ---------------------------------------------------
+ *  See documentation in nsPrintSettingsWin.h
+ *	@update
+ */
+nsPrintSettingsWin::nsPrintSettingsWin()
+    : nsPrintSettings(),
+      mDeviceName(nullptr),
+      mDriverName(nullptr),
+      mDevMode(nullptr) {}
+
+/** ---------------------------------------------------
+ *  See documentation in nsPrintSettingsWin.h
+ *	@update
+ */
+nsPrintSettingsWin::nsPrintSettingsWin(const nsPrintSettingsWin& aPS)
+    : mDevMode(nullptr) {
+  *this = aPS;
+}
+
+/* static */
+void nsPrintSettingsWin::PaperSizeUnitFromDmPaperSize(short aPaperSize,
+                                                      int16_t& aPaperSizeUnit) {
+  if (aPaperSize > 0 && aPaperSize < int32_t(ArrayLength(kPaperSizeUnits))) {
+    aPaperSizeUnit = kPaperSizeUnits[aPaperSize];
+  }
+}
+
+void nsPrintSettingsWin::InitWithInitializer(
+    const PrintSettingsInitializer& aSettings) {
+  nsPrintSettings::InitWithInitializer(aSettings);
+
+  if (aSettings.mDevmodeWStorage.Length() < sizeof(DEVMODEW)) {
+    return;
+  }
+
+  auto* devmode =
+      reinterpret_cast<const DEVMODEW*>(aSettings.mDevmodeWStorage.Elements());
+  if (devmode->dmSize != sizeof(DEVMODEW) ||
+      devmode->dmSize + devmode->dmDriverExtra >
+          aSettings.mDevmodeWStorage.Length()) {
+    return;
+  }
+
+  // SetDevMode copies the DEVMODE.
+  SetDevMode(const_cast<DEVMODEW*>(devmode));
+
+  if (mDevMode->dmFields & DM_SCALE) {
+    // Since we do the scaling, grab the DEVMODE value and reset it back to 100.
+    double scale = double(mDevMode->dmScale) / 100.0f;
+    if (mScaling == 1.0 || scale != 1.0) {
+      SetScaling(scale);
+    }
+    mDevMode->dmScale = 100;
+  }
+}
+
+already_AddRefed<nsIPrintSettings> CreatePlatformPrintSettings(
+    const PrintSettingsInitializer& aSettings) {
+  RefPtr<nsPrintSettings> settings = aSettings.mPrintSettings.get();
+  if (!settings) {
+    settings = MakeRefPtr<nsPrintSettingsWin>();
+  }
+  settings->InitWithInitializer(aSettings);
+  return settings.forget();
+}
+
+/** ---------------------------------------------------
+ *  See documentation in nsPrintSettingsWin.h
+ *	@update
+ */
+nsPrintSettingsWin::~nsPrintSettingsWin() {
+  if (mDevMode) ::HeapFree(::GetProcessHeap(), 0, mDevMode);
+}
+
+NS_IMETHODIMP nsPrintSettingsWin::SetDeviceName(const nsAString& aDeviceName) {
+  mDeviceName = aDeviceName;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettingsWin::GetDeviceName(nsAString& aDeviceName) {
+  aDeviceName = mDeviceName;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettingsWin::SetDriverName(const nsAString& aDriverName) {
+  mDriverName = aDriverName;
+  return NS_OK;
+}
+NS_IMETHODIMP nsPrintSettingsWin::GetDriverName(nsAString& aDriverName) {
+  aDriverName = mDriverName;
+  return NS_OK;
+}
+
+void nsPrintSettingsWin::CopyDevMode(DEVMODEW* aInDevMode,
+                                     DEVMODEW*& aOutDevMode) {
+  aOutDevMode = nullptr;
+  size_t size = aInDevMode->dmSize + aInDevMode->dmDriverExtra;
+  aOutDevMode =
+      (LPDEVMODEW)::HeapAlloc(::GetProcessHeap(), HEAP_ZERO_MEMORY, size);
+  if (aOutDevMode) {
+    memcpy(aOutDevMode, aInDevMode, size);
+  }
+}
+
+NS_IMETHODIMP nsPrintSettingsWin::GetDevMode(DEVMODEW** aDevMode) {
+  NS_ENSURE_ARG_POINTER(aDevMode);
+
+  if (mDevMode) {
+    CopyDevMode(mDevMode, *aDevMode);
+  } else {
+    *aDevMode = nullptr;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsPrintSettingsWin::SetDevMode(DEVMODEW* aDevMode) {
+  if (mDevMode) {
+    ::HeapFree(::GetProcessHeap(), 0, mDevMode);
+    mDevMode = nullptr;
+  }
+
+  if (aDevMode) {
+    CopyDevMode(aDevMode, mDevMode);
+  }
+  return NS_OK;
+}
+
+void nsPrintSettingsWin::InitUnwriteableMargin(HDC aHdc) {
+  mozilla::gfx::MarginDouble margin =
+      mozilla::widget::WinUtils::GetUnwriteableMarginsForDeviceInInches(aHdc);
+
+  mUnwriteableMargin.SizeTo(NS_INCHES_TO_INT_TWIPS(margin.top),
+                            NS_INCHES_TO_INT_TWIPS(margin.right),
+                            NS_INCHES_TO_INT_TWIPS(margin.bottom),
+                            NS_INCHES_TO_INT_TWIPS(margin.left));
+}
+
+void nsPrintSettingsWin::CopyFromNative(HDC aHdc, DEVMODEW* aDevMode) {
+  MOZ_ASSERT(aHdc);
+  MOZ_ASSERT(aDevMode);
+
+  mIsInitedFromPrinter = true;
+  if (aDevMode->dmFields & DM_ORIENTATION) {
+    const bool areSheetsOfPaperPortraitMode =
+        (aDevMode->dmOrientation == DMORIENT_PORTRAIT);
+
+    // If our Windows print settings say that we're producing portrait-mode
+    // sheets of paper, then our page format must also be portrait-mode; unless
+    // we've got a pages-per-sheet value with orthogonal pages/sheets, in which
+    // case it's reversed.
+    const bool arePagesPortraitMode =
+        (areSheetsOfPaperPortraitMode != HasOrthogonalPagesPerSheet());
+
+    // Record the orientation of the pages (determined above) in mOrientation:
+    mOrientation = int32_t(arePagesPortraitMode ? kPortraitOrientation
+                                                : kLandscapeOrientation);
+  }
+
+  if (aDevMode->dmFields & DM_COPIES) {
+    mNumCopies = aDevMode->dmCopies;
+  }
+
+  if (aDevMode->dmFields & DM_DUPLEX) {
+    switch (aDevMode->dmDuplex) {
+      default:
+        MOZ_FALLTHROUGH_ASSERT("bad value for dmDuplex field");
+      case DMDUP_SIMPLEX:
+        mDuplex = kDuplexNone;
+        break;
+      case DMDUP_VERTICAL:
+        mDuplex = kDuplexFlipOnLongEdge;
+        break;
+      case DMDUP_HORIZONTAL:
+        mDuplex = kDuplexFlipOnShortEdge;
+        break;
+    }
+  }
+
+  // Since we do the scaling, grab their value and reset back to 100.
+  if (aDevMode->dmFields & DM_SCALE) {
+    double scale = double(aDevMode->dmScale) / 100.0f;
+    if (mScaling == 1.0 || scale != 1.0) {
+      mScaling = scale;
+    }
+    aDevMode->dmScale = 100;
+  }
+
+  if (aDevMode->dmFields & DM_PAPERSIZE) {
+    mPaperId.Truncate(0);
+    mPaperId.AppendInt(aDevMode->dmPaperSize);
+    // If it is not a paper size we know about, the unit will remain unchanged.
+    PaperSizeUnitFromDmPaperSize(aDevMode->dmPaperSize, mPaperSizeUnit);
+  }
+
+  if (aDevMode->dmFields & DM_COLOR) {
+    mPrintInColor = aDevMode->dmColor == DMCOLOR_COLOR;
+  }
+
+  InitUnwriteableMargin(aHdc);
+
+  int pixelsPerInchY = ::GetDeviceCaps(aHdc, LOGPIXELSY);
+  int physicalHeight = ::GetDeviceCaps(aHdc, PHYSICALHEIGHT);
+  double physicalHeightInch = double(physicalHeight) / pixelsPerInchY;
+  int pixelsPerInchX = ::GetDeviceCaps(aHdc, LOGPIXELSX);
+  int physicalWidth = ::GetDeviceCaps(aHdc, PHYSICALWIDTH);
+  double physicalWidthInch = double(physicalWidth) / pixelsPerInchX;
+
+  // Get the paper size from the device context rather than the DEVMODE, because
+  // it is always available.
+  double paperHeightInch = mOrientation == kPortraitOrientation
+                               ? physicalHeightInch
+                               : physicalWidthInch;
+  mPaperHeight = mPaperSizeUnit == kPaperSizeInches
+                     ? paperHeightInch
+                     : paperHeightInch * MM_PER_INCH_FLOAT;
+
+  double paperWidthInch = mOrientation == kPortraitOrientation
+                              ? physicalWidthInch
+                              : physicalHeightInch;
+  mPaperWidth = mPaperSizeUnit == kPaperSizeInches
+                    ? paperWidthInch
+                    : paperWidthInch * MM_PER_INCH_FLOAT;
+
+  // Using LOGPIXELSY to match existing code for print scaling calculations.
+  mResolution = pixelsPerInchY;
+}
+
+void nsPrintSettingsWin::CopyToNative(DEVMODEW* aDevMode) {
+  MOZ_ASSERT(aDevMode);
+
+  if (!mPaperId.IsEmpty()) {
+    aDevMode->dmPaperSize = _wtoi((const wchar_t*)mPaperId.BeginReading());
+    aDevMode->dmFields |= DM_PAPERSIZE;
+  } else {
+    aDevMode->dmPaperSize = 0;
+    aDevMode->dmFields &= ~DM_PAPERSIZE;
+  }
+
+  aDevMode->dmFields |= DM_COLOR;
+  aDevMode->dmColor = mPrintInColor ? DMCOLOR_COLOR : DMCOLOR_MONOCHROME;
+
+  // The length and width in DEVMODE are always in tenths of a millimeter.
+  double tenthsOfAmmPerSizeUnit =
+      mPaperSizeUnit == kPaperSizeInches ? MM_PER_INCH_FLOAT * 10.0 : 10.0;
+
+  // Note: small page sizes can be required here for sticker, label and slide
+  // printers etc. see bug 1271900.
+  if (mPaperHeight > 0) {
+    aDevMode->dmPaperLength = std::round(mPaperHeight * tenthsOfAmmPerSizeUnit);
+    aDevMode->dmFields |= DM_PAPERLENGTH;
+  } else {
+    aDevMode->dmPaperLength = 0;
+    aDevMode->dmFields &= ~DM_PAPERLENGTH;
+  }
+
+  if (mPaperWidth > 0) {
+    aDevMode->dmPaperWidth = std::round(mPaperWidth * tenthsOfAmmPerSizeUnit);
+    aDevMode->dmFields |= DM_PAPERWIDTH;
+  } else {
+    aDevMode->dmPaperWidth = 0;
+    aDevMode->dmFields &= ~DM_PAPERWIDTH;
+  }
+
+  // Setup Orientation
+  aDevMode->dmOrientation = GetSheetOrientation() == kPortraitOrientation
+                                ? DMORIENT_PORTRAIT
+                                : DMORIENT_LANDSCAPE;
+  aDevMode->dmFields |= DM_ORIENTATION;
+
+  // Setup Number of Copies
+  aDevMode->dmCopies = mNumCopies;
+  aDevMode->dmFields |= DM_COPIES;
+
+  // Setup Simplex/Duplex mode
+  switch (mDuplex) {
+    case kDuplexNone:
+      aDevMode->dmDuplex = DMDUP_SIMPLEX;
+      aDevMode->dmFields |= DM_DUPLEX;
+      break;
+    case kDuplexFlipOnLongEdge:
+      aDevMode->dmDuplex = DMDUP_VERTICAL;
+      aDevMode->dmFields |= DM_DUPLEX;
+      break;
+    case kDuplexFlipOnShortEdge:
+      aDevMode->dmDuplex = DMDUP_HORIZONTAL;
+      aDevMode->dmFields |= DM_DUPLEX;
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE("bad value for duplex option");
+      break;
+  }
+}
+
+//-------------------------------------------
+nsresult nsPrintSettingsWin::_Clone(nsIPrintSettings** _retval) {
+  RefPtr<nsPrintSettingsWin> printSettings = new nsPrintSettingsWin(*this);
+  printSettings.forget(_retval);
+  return NS_OK;
+}
+
+//-------------------------------------------
+nsPrintSettingsWin& nsPrintSettingsWin::operator=(
+    const nsPrintSettingsWin& rhs) {
+  if (this == &rhs) {
+    return *this;
+  }
+
+  ((nsPrintSettings&)*this) = rhs;
+
+  // Use free because we used the native malloc to create the memory
+  if (mDevMode) {
+    ::HeapFree(::GetProcessHeap(), 0, mDevMode);
+  }
+
+  mDeviceName = rhs.mDeviceName;
+  mDriverName = rhs.mDriverName;
+
+  if (rhs.mDevMode) {
+    CopyDevMode(rhs.mDevMode, mDevMode);
+  } else {
+    mDevMode = nullptr;
+  }
+
+  return *this;
+}
+
+//-------------------------------------------
+nsresult nsPrintSettingsWin::_Assign(nsIPrintSettings* aPS) {
+  nsPrintSettingsWin* psWin = static_cast<nsPrintSettingsWin*>(aPS);
+  *this = *psWin;
+  return NS_OK;
+}
diff --git a/widget/windows/nsPrintSettingsWin.h b/widget/windows/nsPrintSettingsWin.h
new file mode 100644
index 0000000000..c127efbeb6
--- /dev/null
+++ b/widget/windows/nsPrintSettingsWin.h
@@ -0,0 +1,62 @@
+/* -*- Mode: IDL; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrintSettingsWin_h__
+#define nsPrintSettingsWin_h__
+
+#include "nsPrintSettingsImpl.h"
+#include "nsIPrintSettingsWin.h"
+#include <windows.h>
+
+//*****************************************************************************
+//***    nsPrintSettingsWin
+//*****************************************************************************
+class nsPrintSettingsWin : public nsPrintSettings, public nsIPrintSettingsWin {
+  virtual ~nsPrintSettingsWin();
+
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIPRINTSETTINGSWIN
+
+  nsPrintSettingsWin();
+  nsPrintSettingsWin(const nsPrintSettingsWin& aPS);
+
+  /**
+   * @param aPaperSize the Windows dmPaperSize
+   * @param aPaperSizeUnit will be set to the nsIPrintSettings paper size unit
+   *                       associated with aPaperSize or left unchanged if
+   *                       aPaperSize is not recognized
+   */
+  static void PaperSizeUnitFromDmPaperSize(short aPaperSize,
+                                           int16_t& aPaperSizeUnit);
+
+  void InitWithInitializer(const PrintSettingsInitializer& aSettings) final;
+
+  /**
+   * Makes a new copy
+   */
+  virtual nsresult _Clone(nsIPrintSettings** _retval);
+
+  /**
+   * Assigns values
+   */
+  virtual nsresult _Assign(nsIPrintSettings* aPS);
+
+  /**
+   * Assignment
+   */
+  nsPrintSettingsWin& operator=(const nsPrintSettingsWin& rhs);
+
+ protected:
+  void CopyDevMode(DEVMODEW* aInDevMode, DEVMODEW*& aOutDevMode);
+  void InitUnwriteableMargin(HDC aHdc);
+
+  nsString mDeviceName;
+  nsString mDriverName;
+  LPDEVMODEW mDevMode;
+};
+
+#endif /* nsPrintSettingsWin_h__ */
diff --git a/widget/windows/nsPrinterWin.cpp b/widget/windows/nsPrinterWin.cpp
new file mode 100644
index 0000000000..75676cd613
--- /dev/null
+++ b/widget/windows/nsPrinterWin.cpp
@@ -0,0 +1,521 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPrinterWin.h"
+
+#include <algorithm>
+#include <windows.h>
+#include <winspool.h>
+
+#include "mozilla/Array.h"
+#include "mozilla/dom/Promise.h"
+#include "nsPaper.h"
+#include "nsPrintSettingsImpl.h"
+#include "nsPrintSettingsWin.h"
+#include "nsWindowsHelpers.h"
+#include "PrintBackgroundTask.h"
+#include "WinUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using namespace mozilla::widget;
+using mozilla::PrintSettingsInitializer;
+using mozilla::dom::Promise;
+
+static const double kPointsPerTenthMM = 72.0 / 254.0;
+static const double kPointsPerInch = 72.0;
+
+nsPrinterWin::nsPrinterWin(const CommonPaperInfoArray* aArray,
+                           const nsAString& aName)
+    : nsPrinterBase(aArray),
+      mName(aName),
+      mDefaultDevmodeWStorage("nsPrinterWin::mDefaultDevmodeWStorage") {}
+
+// static
+already_AddRefed<nsPrinterWin> nsPrinterWin::Create(
+    const CommonPaperInfoArray* aArray, const nsAString& aName) {
+  return do_AddRef(new nsPrinterWin(aArray, aName));
+}
+
+template <class T>
+static nsTArray<T> GetDeviceCapabilityArray(const LPWSTR aPrinterName,
+                                            WORD aCapabilityID,
+                                            mozilla::Mutex& aDriverMutex,
+                                            int& aCount) {
+  MOZ_ASSERT(aCount >= 0, "Possibly passed aCount from previous error case.");
+
+  nsTArray<T> caps;
+
+  // We only want to access printer drivers in the parent process.
+  if (!XRE_IsParentProcess()) {
+    return caps;
+  }
+
+  // Both the call to get the size and the call to actually populate the array
+  // are relatively expensive, so as sometimes the lengths of the arrays that we
+  // retrieve depend on each other we allow a count to be passed in to save the
+  // first call. As we allocate double the count anyway this should allay any
+  // safety worries.
+  if (!aCount) {
+    // Passing nullptr as the port here seems to work. Given that we would have
+    // to OpenPrinter with just the name anyway to get the port that makes
+    // sense. Also, the printer set-up seems to stop you from having two
+    // printers with the same name. Note: this (and the call below) are blocking
+    // calls, which could be slow.
+    MutexAutoLock autoLock(aDriverMutex);
+    aCount = ::DeviceCapabilitiesW(aPrinterName, nullptr, aCapabilityID,
+                                   nullptr, nullptr);
+    if (aCount <= 0) {
+      return caps;
+    }
+  }
+
+  // As DeviceCapabilitiesW doesn't take a size, there is a greater risk of the
+  // buffer being overflowed, so we over-allocate for safety.
+  caps.SetLength(aCount * 2);
+  MutexAutoLock autoLock(aDriverMutex);
+  int count =
+      ::DeviceCapabilitiesW(aPrinterName, nullptr, aCapabilityID,
+                            reinterpret_cast<LPWSTR>(caps.Elements()), nullptr);
+  if (count <= 0) {
+    caps.Clear();
+    return caps;
+  }
+
+  // We know from bug 1673708 that sometimes the final array returned is smaller
+  // than the required array count. Assert here to see if this is reproduced on
+  // test servers.
+  MOZ_ASSERT(count == aCount, "Different array count returned than expected.");
+
+  // Note that TruncateLength will crash if count > caps.Length().
+  caps.TruncateLength(count);
+  return caps;
+}
+
+static void DevmodeToSettingsInitializer(
+    const nsString& aPrinterName, const DEVMODEW* aDevmode,
+    mozilla::Mutex& aDriverMutex,
+    PrintSettingsInitializer& aSettingsInitializer) {
+  aSettingsInitializer.mPrinter.Assign(aPrinterName);
+
+  HDC dc;
+  {
+    MutexAutoLock autoLock(aDriverMutex);
+    dc = ::CreateICW(nullptr, aPrinterName.get(), nullptr, aDevmode);
+  }
+  nsAutoHDC printerDc(dc);
+  MOZ_ASSERT(printerDc, "CreateICW failed");
+  if (!printerDc) {
+    return;
+  }
+
+  if (aDevmode->dmFields & DM_PAPERSIZE) {
+    aSettingsInitializer.mPaperInfo.mId.Truncate();
+    aSettingsInitializer.mPaperInfo.mId.AppendInt(aDevmode->dmPaperSize);
+    // If it is not a paper size we know about, the unit will remain unchanged.
+    nsPrintSettingsWin::PaperSizeUnitFromDmPaperSize(
+        aDevmode->dmPaperSize, aSettingsInitializer.mPaperSizeUnit);
+  }
+
+  int pixelsPerInchY = ::GetDeviceCaps(printerDc, LOGPIXELSY);
+  int physicalHeight = ::GetDeviceCaps(printerDc, PHYSICALHEIGHT);
+  double heightInInches = double(physicalHeight) / pixelsPerInchY;
+  int pixelsPerInchX = ::GetDeviceCaps(printerDc, LOGPIXELSX);
+  int physicalWidth = ::GetDeviceCaps(printerDc, PHYSICALWIDTH);
+  double widthInches = double(physicalWidth) / pixelsPerInchX;
+  if (aDevmode->dmFields & DM_ORIENTATION &&
+      aDevmode->dmOrientation == DMORIENT_LANDSCAPE) {
+    std::swap(widthInches, heightInInches);
+  }
+  aSettingsInitializer.mPaperInfo.mSize.SizeTo(widthInches * kPointsPerInch,
+                                               heightInInches * kPointsPerInch);
+
+  gfx::MarginDouble margin =
+      WinUtils::GetUnwriteableMarginsForDeviceInInches(printerDc);
+  aSettingsInitializer.mPaperInfo.mUnwriteableMargin = Some(MarginDouble{
+      margin.top * kPointsPerInch, margin.right * kPointsPerInch,
+      margin.bottom * kPointsPerInch, margin.left * kPointsPerInch});
+
+  // Using Y to match existing code for print scaling calculations.
+  aSettingsInitializer.mResolution = pixelsPerInchY;
+
+  if (aDevmode->dmFields & DM_COLOR) {
+    // See comment for PrintSettingsInitializer.mPrintInColor
+    aSettingsInitializer.mPrintInColor =
+        aDevmode->dmColor != DMCOLOR_MONOCHROME;
+  }
+
+  if (aDevmode->dmFields & DM_ORIENTATION) {
+    aSettingsInitializer.mSheetOrientation =
+        int32_t(aDevmode->dmOrientation == DMORIENT_PORTRAIT
+                    ? nsPrintSettings::kPortraitOrientation
+                    : nsPrintSettings::kLandscapeOrientation);
+  }
+
+  if (aDevmode->dmFields & DM_COPIES) {
+    aSettingsInitializer.mNumCopies = aDevmode->dmCopies;
+  }
+
+  if (aDevmode->dmFields & DM_DUPLEX) {
+    switch (aDevmode->dmDuplex) {
+      default:
+        MOZ_FALLTHROUGH_ASSERT("bad value for dmDuplex field");
+      case DMDUP_SIMPLEX:
+        aSettingsInitializer.mDuplex = nsPrintSettings::kDuplexNone;
+        break;
+      case DMDUP_VERTICAL:
+        aSettingsInitializer.mDuplex = nsPrintSettings::kDuplexFlipOnLongEdge;
+        break;
+      case DMDUP_HORIZONTAL:
+        aSettingsInitializer.mDuplex = nsPrintSettings::kDuplexFlipOnShortEdge;
+        break;
+    }
+  }
+}
+
+NS_IMETHODIMP
+nsPrinterWin::GetName(nsAString& aName) {
+  aName.Assign(mName);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsPrinterWin::GetSystemName(nsAString& aName) {
+  aName.Assign(mName);
+  return NS_OK;
+}
+
+namespace mozilla {
+template <>
+void ResolveOrReject(Promise& aPromise, nsPrinterWin& aPrinter,
+                     const PrintSettingsInitializer& aResult) {
+  aPromise.MaybeResolve(
+      RefPtr<nsIPrintSettings>(CreatePlatformPrintSettings(aResult)));
+}
+}  // namespace mozilla
+
+NS_IMETHODIMP nsPrinterWin::CopyFromWithValidation(
+    nsIPrintSettings* aSettingsToCopyFrom, JSContext* aCx,
+    Promise** aResultPromise) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aResultPromise);
+
+  PrintSettingsInitializer settingsInitializer =
+      aSettingsToCopyFrom->GetSettingsInitializer();
+  return PrintBackgroundTaskPromise(
+      *this, aCx, aResultPromise, "CopyFromWithValidation"_ns,
+      &nsPrinterWin::GetValidatedSettings, settingsInitializer);
+}
+
+bool nsPrinterWin::SupportsDuplex() const {
+  MutexAutoLock autoLock(mDriverMutex);
+  return ::DeviceCapabilitiesW(mName.get(), nullptr, DC_DUPLEX, nullptr,
+                               nullptr) == 1;
+}
+
+bool nsPrinterWin::SupportsColor() const {
+  MutexAutoLock autoLock(mDriverMutex);
+  return ::DeviceCapabilitiesW(mName.get(), nullptr, DC_COLORDEVICE, nullptr,
+                               nullptr) == 1;
+}
+
+bool nsPrinterWin::SupportsMonochrome() const {
+  if (!SupportsColor()) {
+    return true;
+  }
+
+  nsHPRINTER hPrinter = nullptr;
+  if (NS_WARN_IF(!::OpenPrinterW(mName.get(), &hPrinter, nullptr))) {
+    return false;
+  }
+  nsAutoPrinter autoPrinter(hPrinter);
+
+  nsTArray<uint8_t> devmodeWStorage = CopyDefaultDevmodeW();
+  if (devmodeWStorage.IsEmpty()) {
+    return false;
+  }
+
+  auto* devmode = reinterpret_cast<DEVMODEW*>(devmodeWStorage.Elements());
+
+  devmode->dmFields |= DM_COLOR;
+  devmode->dmColor = DMCOLOR_MONOCHROME;
+  // Try to modify the devmode settings and see if the setting sticks.
+  //
+  // This has been the only reliable way to detect it that we've found.
+  MutexAutoLock autoLock(mDriverMutex);
+  LONG ret =
+      ::DocumentPropertiesW(nullptr, autoPrinter.get(), mName.get(), devmode,
+                            devmode, DM_IN_BUFFER | DM_OUT_BUFFER);
+  if (ret != IDOK) {
+    return false;
+  }
+  return !(devmode->dmFields & DM_COLOR) ||
+         devmode->dmColor == DMCOLOR_MONOCHROME;
+}
+
+bool nsPrinterWin::SupportsCollation() const {
+  MutexAutoLock autoLock(mDriverMutex);
+  return ::DeviceCapabilitiesW(mName.get(), nullptr, DC_COLLATE, nullptr,
+                               nullptr) == 1;
+}
+
+nsPrinterBase::PrinterInfo nsPrinterWin::CreatePrinterInfo() const {
+  return PrinterInfo{PaperList(), DefaultSettings()};
+}
+
+mozilla::gfx::MarginDouble nsPrinterWin::GetMarginsForPaper(
+    nsString aPaperId) const {
+  gfx::MarginDouble margin;
+
+  nsTArray<uint8_t> devmodeWStorage = CopyDefaultDevmodeW();
+  if (devmodeWStorage.IsEmpty()) {
+    return margin;
+  }
+
+  auto* devmode = reinterpret_cast<DEVMODEW*>(devmodeWStorage.Elements());
+
+  devmode->dmFields = DM_PAPERSIZE;
+  devmode->dmPaperSize = _wtoi((const wchar_t*)aPaperId.BeginReading());
+  HDC dc;
+  {
+    MutexAutoLock autoLock(mDriverMutex);
+    dc = ::CreateICW(nullptr, mName.get(), nullptr, devmode);
+  }
+  nsAutoHDC printerDc(dc);
+  MOZ_ASSERT(printerDc, "CreateICW failed");
+  if (!printerDc) {
+    return margin;
+  }
+  margin = WinUtils::GetUnwriteableMarginsForDeviceInInches(printerDc);
+  margin.top *= kPointsPerInch;
+  margin.right *= kPointsPerInch;
+  margin.bottom *= kPointsPerInch;
+  margin.left *= kPointsPerInch;
+
+  return margin;
+}
+
+nsTArray<uint8_t> nsPrinterWin::CopyDefaultDevmodeW() const {
+  nsTArray<uint8_t> devmodeStorageW;
+
+  auto devmodeStorageWLock = mDefaultDevmodeWStorage.Lock();
+  if (devmodeStorageWLock->IsEmpty()) {
+    nsHPRINTER hPrinter = nullptr;
+    // OpenPrinter could fail if, for example, the printer has been removed
+    // or otherwise become inaccessible since it was selected.
+    if (NS_WARN_IF(!::OpenPrinterW(mName.get(), &hPrinter, nullptr))) {
+      return devmodeStorageW;
+    }
+    nsAutoPrinter autoPrinter(hPrinter);
+    // Allocate devmode storage of the correct size.
+    MutexAutoLock autoLock(mDriverMutex);
+    LONG bytesNeeded = ::DocumentPropertiesW(nullptr, autoPrinter.get(),
+                                             mName.get(), nullptr, nullptr, 0);
+    // Note that we must cast the sizeof() to a signed type so that comparison
+    // with the signed, potentially-negative bytesNeeded will work!
+    MOZ_ASSERT(bytesNeeded >= LONG(sizeof(DEVMODEW)),
+               "DocumentPropertiesW failed to get valid size");
+    if (bytesNeeded < LONG(sizeof(DEVMODEW))) {
+      return devmodeStorageW;
+    }
+
+    // Allocate extra space in case of bad drivers that return a too-small
+    // result from DocumentProperties.
+    // (See https://bugzilla.mozilla.org/show_bug.cgi?id=1664530#c5)
+    if (!devmodeStorageWLock->SetLength(bytesNeeded * 2, fallible)) {
+      return devmodeStorageW;
+    }
+
+    memset(devmodeStorageWLock->Elements(), 0, devmodeStorageWLock->Length());
+    auto* devmode =
+        reinterpret_cast<DEVMODEW*>(devmodeStorageWLock->Elements());
+    LONG ret = ::DocumentPropertiesW(nullptr, autoPrinter.get(), mName.get(),
+                                     devmode, nullptr, DM_OUT_BUFFER);
+    MOZ_ASSERT(ret == IDOK, "DocumentPropertiesW failed");
+    // Make sure that the lengths in the DEVMODEW make sense.
+    if (ret != IDOK || devmode->dmSize != sizeof(DEVMODEW) ||
+        devmode->dmSize + devmode->dmDriverExtra >
+            devmodeStorageWLock->Length()) {
+      // Clear mDefaultDevmodeWStorage to make sure we try again next time.
+      devmodeStorageWLock->Clear();
+      return devmodeStorageW;
+    }
+  }
+
+  devmodeStorageW.Assign(devmodeStorageWLock.ref());
+  return devmodeStorageW;
+}
+
+nsTArray<mozilla::PaperInfo> nsPrinterWin::PaperList() const {
+  // Paper IDs are returned as WORDs.
+  int requiredArrayCount = 0;
+  auto paperIds = GetDeviceCapabilityArray<WORD>(
+      mName.get(), DC_PAPERS, mDriverMutex, requiredArrayCount);
+  if (!paperIds.Length()) {
+    return {};
+  }
+
+  // Paper names are returned in 64 long character buffers.
+  auto paperNames = GetDeviceCapabilityArray<Array<wchar_t, 64>>(
+      mName.get(), DC_PAPERNAMES, mDriverMutex, requiredArrayCount);
+  // Check that we have the same number of names as IDs.
+  if (paperNames.Length() != paperIds.Length()) {
+    return {};
+  }
+
+  // Paper sizes are returned as POINT structs with a tenth of a millimeter as
+  // the unit.
+  auto paperSizes = GetDeviceCapabilityArray<POINT>(
+      mName.get(), DC_PAPERSIZE, mDriverMutex, requiredArrayCount);
+  // Check that we have the same number of sizes as IDs.
+  if (paperSizes.Length() != paperIds.Length()) {
+    return {};
+  }
+
+  nsTArray<mozilla::PaperInfo> paperList;
+  paperList.SetCapacity(paperNames.Length());
+  for (size_t i = 0; i < paperNames.Length(); ++i) {
+    // Paper names are null terminated unless they are 64 characters long.
+    auto firstNull =
+        std::find(paperNames[i].cbegin(), paperNames[i].cend(), L'\0');
+    auto nameLength = firstNull - paperNames[i].cbegin();
+    double width = paperSizes[i].x * kPointsPerTenthMM;
+    double height = paperSizes[i].y * kPointsPerTenthMM;
+
+    // Skip if no name or invalid size.
+    if (!nameLength || width <= 0 || height <= 0) {
+      continue;
+    }
+
+    // Windows paper IDs are 16-bit integers; we stringify them to store in the
+    // PaperInfo.mId field.
+    nsString paperIdString;
+    paperIdString.AppendInt(paperIds[i]);
+
+    // We don't resolve the margins eagerly because they're really expensive (on
+    // the order of seconds for some drivers).
+    nsDependentSubstring name(paperNames[i].cbegin(), nameLength);
+    paperList.AppendElement(mozilla::PaperInfo(paperIdString, nsString(name),
+                                               {width, height}, Nothing()));
+  }
+
+  return paperList;
+}
+
+PrintSettingsInitializer nsPrinterWin::DefaultSettings() const {
+  nsTArray<uint8_t> devmodeWStorage = CopyDefaultDevmodeW();
+  if (devmodeWStorage.IsEmpty()) {
+    return {};
+  }
+
+  const auto* devmode =
+      reinterpret_cast<const DEVMODEW*>(devmodeWStorage.Elements());
+
+  PrintSettingsInitializer settingsInitializer;
+  DevmodeToSettingsInitializer(mName, devmode, mDriverMutex,
+                               settingsInitializer);
+  settingsInitializer.mDevmodeWStorage = std::move(devmodeWStorage);
+  return settingsInitializer;
+}
+
+PrintSettingsInitializer nsPrinterWin::GetValidatedSettings(
+    PrintSettingsInitializer aSettingsToValidate) const {
+  // This function validates the settings by relying on the printer driver
+  // rejecting any invalid settings and resetting them to valid values.
+
+  // Create a copy of the default DEVMODE for this printer.
+  nsTArray<uint8_t> devmodeWStorage = CopyDefaultDevmodeW();
+  if (devmodeWStorage.IsEmpty()) {
+    return aSettingsToValidate;
+  }
+
+  nsHPRINTER hPrinter = nullptr;
+  if (NS_WARN_IF(!::OpenPrinterW(mName.get(), &hPrinter, nullptr))) {
+    return aSettingsToValidate;
+  }
+  nsAutoPrinter autoPrinter(hPrinter);
+
+  // Copy the settings from aSettingsToValidate into our DEVMODE.
+  DEVMODEW* devmode = reinterpret_cast<DEVMODEW*>(devmodeWStorage.Elements());
+  if (!aSettingsToValidate.mPaperInfo.mId.IsEmpty()) {
+    devmode->dmPaperSize = _wtoi(
+        (const wchar_t*)aSettingsToValidate.mPaperInfo.mId.BeginReading());
+    devmode->dmFields |= DM_PAPERSIZE;
+  } else {
+    devmode->dmPaperSize = 0;
+    devmode->dmFields &= ~DM_PAPERSIZE;
+  }
+
+  devmode->dmFields |= DM_COLOR;
+  devmode->dmColor =
+      aSettingsToValidate.mPrintInColor ? DMCOLOR_COLOR : DMCOLOR_MONOCHROME;
+
+  // Note: small page sizes can be required here for sticker, label and slide
+  // printers etc. see bug 1271900.
+  if (aSettingsToValidate.mPaperInfo.mSize.height > 0) {
+    devmode->dmPaperLength = std::round(
+        aSettingsToValidate.mPaperInfo.mSize.height / kPointsPerTenthMM);
+    devmode->dmFields |= DM_PAPERLENGTH;
+  } else {
+    devmode->dmPaperLength = 0;
+    devmode->dmFields &= ~DM_PAPERLENGTH;
+  }
+
+  if (aSettingsToValidate.mPaperInfo.mSize.width > 0) {
+    devmode->dmPaperWidth = std::round(
+        aSettingsToValidate.mPaperInfo.mSize.width / kPointsPerTenthMM);
+    devmode->dmFields |= DM_PAPERWIDTH;
+  } else {
+    devmode->dmPaperWidth = 0;
+    devmode->dmFields &= ~DM_PAPERWIDTH;
+  }
+
+  // Setup Orientation
+  devmode->dmOrientation = aSettingsToValidate.mSheetOrientation ==
+                                   nsPrintSettings::kPortraitOrientation
+                               ? DMORIENT_PORTRAIT
+                               : DMORIENT_LANDSCAPE;
+  devmode->dmFields |= DM_ORIENTATION;
+
+  // Setup Number of Copies
+  devmode->dmCopies = aSettingsToValidate.mNumCopies;
+  devmode->dmFields |= DM_COPIES;
+
+  // Setup Simplex/Duplex mode
+  devmode->dmFields |= DM_DUPLEX;
+  switch (aSettingsToValidate.mDuplex) {
+    case nsPrintSettings::kDuplexNone:
+      devmode->dmDuplex = DMDUP_SIMPLEX;
+      break;
+    case nsPrintSettings::kDuplexFlipOnLongEdge:
+      devmode->dmDuplex = DMDUP_VERTICAL;
+      break;
+    case nsPrintSettings::kDuplexFlipOnShortEdge:
+      devmode->dmDuplex = DMDUP_HORIZONTAL;
+      break;
+    default:
+      MOZ_ASSERT_UNREACHABLE("bad value for duplex option");
+      break;
+  }
+
+  // Apply the settings in the DEVMODE to the printer and retrieve the updated
+  // DEVMODE back into the same structure.
+  LONG ret;
+  {
+    MutexAutoLock autoLock(mDriverMutex);
+    ret = ::DocumentPropertiesW(nullptr, autoPrinter.get(), mName.get(),
+                                devmode, devmode, DM_IN_BUFFER | DM_OUT_BUFFER);
+  }
+  if (ret != IDOK) {
+    return aSettingsToValidate;
+  }
+
+  // Copy the settings back from the DEVMODE into aSettingsToValidate and
+  // return.
+  DevmodeToSettingsInitializer(mName, devmode, mDriverMutex,
+                               aSettingsToValidate);
+  aSettingsToValidate.mDevmodeWStorage = std::move(devmodeWStorage);
+  return aSettingsToValidate;
+}
diff --git a/widget/windows/nsPrinterWin.h b/widget/windows/nsPrinterWin.h
new file mode 100644
index 0000000000..8afcf14d0e
--- /dev/null
+++ b/widget/windows/nsPrinterWin.h
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsPrinterWin_h_
+#define nsPrinterWin_h_
+
+#include "nsPrinterBase.h"
+#include "mozilla/DataMutex.h"
+#include "nsTArrayForwardDeclare.h"
+
+class nsPrinterWin final : public nsPrinterBase {
+ public:
+  NS_IMETHOD GetName(nsAString& aName) override;
+  NS_IMETHOD GetSystemName(nsAString& aName) override;
+  NS_IMETHOD CopyFromWithValidation(nsIPrintSettings*, JSContext*,
+                                    Promise**) final;
+  bool SupportsDuplex() const final;
+  bool SupportsColor() const final;
+  bool SupportsMonochrome() const final;
+  bool SupportsCollation() const final;
+  PrinterInfo CreatePrinterInfo() const final;
+  MarginDouble GetMarginsForPaper(nsString aPaperId) const final;
+
+  nsPrinterWin() = delete;
+  static already_AddRefed<nsPrinterWin> Create(
+      const mozilla::CommonPaperInfoArray* aPaperInfoArray,
+      const nsAString& aName);
+
+ private:
+  nsPrinterWin(const mozilla::CommonPaperInfoArray* aPaperInfoArray,
+               const nsAString& aName);
+  ~nsPrinterWin() = default;
+
+  PrintSettingsInitializer GetValidatedSettings(
+      PrintSettingsInitializer aSettingsToValidate) const;
+
+  nsTArray<uint8_t> CopyDefaultDevmodeW() const;
+  nsTArray<mozilla::PaperInfo> PaperList() const;
+  PrintSettingsInitializer DefaultSettings() const;
+
+  const nsString mName;
+  mutable mozilla::DataMutex<nsTArray<uint8_t>> mDefaultDevmodeWStorage;
+  // Even though some documentation seems to suggest that you should be able to
+  // use printer drivers on separate threads if you have separate handles, we
+  // see threading issues with multiple drivers. This Mutex is used to lock
+  // around all calls to DeviceCapabilitiesW, DocumentPropertiesW and
+  // CreateICW/DCW, to hopefully prevent these issues.
+  mutable mozilla::Mutex mDriverMutex MOZ_UNANNOTATED{"nsPrinterWin::Driver"};
+};
+
+#endif  // nsPrinterWin_h_
diff --git a/widget/windows/nsSharePicker.cpp b/widget/windows/nsSharePicker.cpp
new file mode 100644
index 0000000000..9cdc792718
--- /dev/null
+++ b/widget/windows/nsSharePicker.cpp
@@ -0,0 +1,81 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsSharePicker.h"
+
+#include "nsString.h"
+#include "nsThreadUtils.h"
+#include "WindowsUIUtils.h"
+#include "nsPIDOMWindow.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/Unused.h"
+
+using mozilla::dom::Promise;
+
+///////////////////////////////////////////////////////////////////////////////
+// nsISharePicker
+
+NS_IMPL_ISUPPORTS(nsSharePicker, nsISharePicker)
+
+namespace {
+inline NS_ConvertUTF8toUTF16 NS_ConvertUTF8toUTF16_MaybeVoid(
+    const nsACString& aStr) {
+  auto str = NS_ConvertUTF8toUTF16(aStr);
+  str.SetIsVoid(aStr.IsVoid());
+  return str;
+}
+inline nsIGlobalObject* GetGlobalObject() {
+  return xpc::NativeGlobal(xpc::PrivilegedJunkScope());
+}
+}  // namespace
+
+NS_IMETHODIMP
+nsSharePicker::Init(mozIDOMWindowProxy* aOpenerWindow) {
+  if (mInited) {
+    return NS_ERROR_FAILURE;
+  }
+  mOpenerWindow = aOpenerWindow;
+  mInited = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSharePicker::GetOpenerWindow(mozIDOMWindowProxy** aOpenerWindow) {
+  *aOpenerWindow = mOpenerWindow;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSharePicker::Share(const nsACString& aTitle, const nsACString& aText,
+                     nsIURI* aUrl, Promise** aPromise) {
+  mozilla::ErrorResult result;
+  RefPtr<Promise> promise = Promise::Create(GetGlobalObject(), result);
+  if (NS_WARN_IF(result.Failed())) {
+    return result.StealNSResult();
+  }
+  nsAutoCString urlString;
+  if (aUrl) {
+    nsresult rv = aUrl->GetSpec(urlString);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    mozilla::Unused << rv;
+  } else {
+    urlString.SetIsVoid(true);
+  }
+
+  auto mozPromise =
+      WindowsUIUtils::Share(NS_ConvertUTF8toUTF16_MaybeVoid(aTitle),
+                            NS_ConvertUTF8toUTF16_MaybeVoid(aText),
+                            NS_ConvertUTF8toUTF16_MaybeVoid(urlString));
+  mozPromise->Then(
+      mozilla::GetCurrentSerialEventTarget(), __func__,
+      [promise]() { promise->MaybeResolveWithUndefined(); },
+      [promise]() { promise->MaybeReject(NS_ERROR_DOM_ABORT_ERR); });
+
+  promise.forget(aPromise);
+
+  return NS_OK;
+}
diff --git a/widget/windows/nsSharePicker.h b/widget/windows/nsSharePicker.h
new file mode 100644
index 0000000000..d9ba9d2a6d
--- /dev/null
+++ b/widget/windows/nsSharePicker.h
@@ -0,0 +1,29 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsSharePicker_h__
+#define nsSharePicker_h__
+
+#include "nsCOMPtr.h"
+#include "nsISharePicker.h"
+#include "nsPIDOMWindow.h"
+#include "nsThreadUtils.h"
+
+class nsSharePicker : public nsISharePicker {
+  virtual ~nsSharePicker() = default;
+
+ public:
+  nsSharePicker() = default;
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISHAREPICKER
+
+ private:
+  bool mInited = false;
+  mozIDOMWindowProxy* mOpenerWindow;
+};
+
+#endif  // nsSharePicker_h__
diff --git a/widget/windows/nsSound.cpp b/widget/windows/nsSound.cpp
new file mode 100644
index 0000000000..1fecf09c3a
--- /dev/null
+++ b/widget/windows/nsSound.cpp
@@ -0,0 +1,331 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nscore.h"
+#include <stdio.h>
+#include "nsString.h"
+#include <windows.h>
+
+// mmsystem.h is needed to build with WIN32_LEAN_AND_MEAN
+#include <mmsystem.h>
+
+#include "HeadlessSound.h"
+#include "nsSound.h"
+#include "nsIURL.h"
+#include "nsNetUtil.h"
+#include "nsIChannel.h"
+#include "nsContentUtils.h"
+#include "nsCRT.h"
+#include "nsIObserverService.h"
+
+#include "mozilla/Logging.h"
+#include "prtime.h"
+
+#include "nsNativeCharsetUtils.h"
+#include "nsThreadUtils.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "gfxPlatform.h"
+
+using mozilla::LogLevel;
+
+#ifdef DEBUG
+static mozilla::LazyLogModule gWin32SoundLog("nsSound");
+#endif
+
+// Hackaround for bug 1644240
+// When we call PlaySound for the first time in the process, winmm.dll creates
+// a new thread and starts a message loop in winmm!mciwindow.  After that,
+// every call of PlaySound communicates with that thread via Window messages.
+// It seems that Warsaw application hooks USER32!GetMessageA, and there is
+// a timing window where they free their trampoline region without reverting
+// the hook on USER32!GetMessageA, resulting in crash when winmm!mciwindow
+// receives a message because it tries to jump to a freed buffer.
+// Based on the crash reports, it happened on all versions of Windows x64, and
+// the possible condition was wslbdhm64.dll was loaded but wslbscrwh64.dll was
+// unloaded.  Therefore we suppress playing a sound under such a condition.
+static bool ShouldSuppressPlaySound() {
+#if defined(_M_AMD64)
+  if (::GetModuleHandle(L"wslbdhm64.dll") &&
+      !::GetModuleHandle(L"wslbscrwh64.dll")) {
+    return true;
+  }
+#endif  // defined(_M_AMD64)
+  return false;
+}
+
+class nsSoundPlayer : public mozilla::Runnable {
+ public:
+  explicit nsSoundPlayer(const nsAString& aSoundName)
+      : mozilla::Runnable("nsSoundPlayer"),
+        mSoundName(aSoundName),
+        mSoundData(nullptr) {}
+
+  nsSoundPlayer(const uint8_t* aData, size_t aSize)
+      : mozilla::Runnable("nsSoundPlayer"), mSoundName(u""_ns) {
+    MOZ_ASSERT(aSize > 0, "Size should not be zero");
+    MOZ_ASSERT(aData, "Data shoud not be null");
+
+    // We will disptach nsSoundPlayer to playerthread, so keep a data copy
+    mSoundData = new uint8_t[aSize];
+    memcpy(mSoundData, aData, aSize);
+  }
+
+  NS_DECL_NSIRUNNABLE
+
+ protected:
+  ~nsSoundPlayer();
+
+  nsString mSoundName;
+  uint8_t* mSoundData;
+};
+
+NS_IMETHODIMP
+nsSoundPlayer::Run() {
+  if (ShouldSuppressPlaySound()) {
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(!mSoundName.IsEmpty() || mSoundData,
+             "Sound name or sound data should be specified");
+  DWORD flags = SND_NODEFAULT | SND_ASYNC;
+
+  if (mSoundData) {
+    flags |= SND_MEMORY;
+    ::PlaySoundW(reinterpret_cast<LPCWSTR>(mSoundData), nullptr, flags);
+  } else {
+    flags |= SND_ALIAS;
+    ::PlaySoundW(mSoundName.get(), nullptr, flags);
+  }
+  return NS_OK;
+}
+
+nsSoundPlayer::~nsSoundPlayer() { delete[] mSoundData; }
+
+mozilla::StaticRefPtr<nsISound> nsSound::sInstance;
+
+/* static */
+already_AddRefed<nsISound> nsSound::GetInstance() {
+  if (!sInstance) {
+    if (gfxPlatform::IsHeadless()) {
+      sInstance = new mozilla::widget::HeadlessSound();
+    } else {
+      RefPtr<nsSound> sound = new nsSound();
+      nsresult rv = sound->CreatePlayerThread();
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return nullptr;
+      }
+      sInstance = sound.forget();
+    }
+    ClearOnShutdown(&sInstance);
+  }
+
+  RefPtr<nsISound> service = sInstance;
+  return service.forget();
+}
+
+#ifndef SND_PURGE
+// Not available on Windows CE, and according to MSDN
+// doesn't do anything on recent windows either.
+#  define SND_PURGE 0
+#endif
+
+NS_IMPL_ISUPPORTS(nsSound, nsISound, nsIStreamLoaderObserver, nsIObserver)
+
+nsSound::nsSound() : mInited(false) {}
+
+nsSound::~nsSound() {}
+
+void nsSound::PurgeLastSound() {
+  // Halt any currently playing sound.
+  if (mSoundPlayer) {
+    if (mPlayerThread) {
+      mPlayerThread->Dispatch(
+          NS_NewRunnableFunction("nsSound::PurgeLastSound",
+                                 [player = std::move(mSoundPlayer)]() {
+                                   // Capture move mSoundPlayer to lambda then
+                                   // PlaySoundW(nullptr, nullptr, SND_PURGE)
+                                   // will be called before freeing the
+                                   // nsSoundPlayer.
+                                   if (ShouldSuppressPlaySound()) {
+                                     return;
+                                   }
+                                   ::PlaySoundW(nullptr, nullptr, SND_PURGE);
+                                 }),
+          NS_DISPATCH_NORMAL);
+    }
+  }
+}
+
+NS_IMETHODIMP nsSound::Beep() {
+  ::MessageBeep(0);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsSound::OnStreamComplete(nsIStreamLoader* aLoader,
+                                        nsISupports* context, nsresult aStatus,
+                                        uint32_t dataLen, const uint8_t* data) {
+  MOZ_ASSERT(mPlayerThread, "player thread should not be null ");
+  // print a load error on bad status
+  if (NS_FAILED(aStatus)) {
+#ifdef DEBUG
+    if (aLoader) {
+      nsCOMPtr<nsIRequest> request;
+      nsCOMPtr<nsIChannel> channel;
+      aLoader->GetRequest(getter_AddRefs(request));
+      if (request) channel = do_QueryInterface(request);
+      if (channel) {
+        nsCOMPtr<nsIURI> uri;
+        channel->GetURI(getter_AddRefs(uri));
+        if (uri) {
+          nsAutoCString uriSpec;
+          uri->GetSpec(uriSpec);
+          MOZ_LOG(gWin32SoundLog, LogLevel::Info,
+                  ("Failed to load %s\n", uriSpec.get()));
+        }
+      }
+    }
+#endif
+    return aStatus;
+  }
+
+  PurgeLastSound();
+
+  if (data && dataLen > 0) {
+    MOZ_ASSERT(!mSoundPlayer, "mSoundPlayer should be null");
+    mSoundPlayer = new nsSoundPlayer(data, dataLen);
+    MOZ_ASSERT(mSoundPlayer, "Could not create player");
+
+    nsresult rv = mPlayerThread->Dispatch(mSoundPlayer, NS_DISPATCH_NORMAL);
+    if (NS_WARN_IF(FAILED(rv))) {
+      return rv;
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsSound::Play(nsIURL* aURL) {
+  nsresult rv;
+
+#ifdef DEBUG_SOUND
+  char* url;
+  aURL->GetSpec(&url);
+  MOZ_LOG(gWin32SoundLog, LogLevel::Info, ("%s\n", url));
+#endif
+
+  nsCOMPtr<nsIStreamLoader> loader;
+  rv = NS_NewStreamLoader(
+      getter_AddRefs(loader), aURL,
+      this,  // aObserver
+      nsContentUtils::GetSystemPrincipal(),
+      nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
+      nsIContentPolicy::TYPE_OTHER);
+  return rv;
+}
+
+nsresult nsSound::CreatePlayerThread() {
+  if (mPlayerThread) {
+    return NS_OK;
+  }
+  if (NS_WARN_IF(NS_FAILED(NS_NewNamedThread("PlayEventSound",
+                                             getter_AddRefs(mPlayerThread))))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Add an observer for shutdown event to release the thread at that time
+  nsCOMPtr<nsIObserverService> observerService =
+      mozilla::services::GetObserverService();
+  if (!observerService) {
+    return NS_ERROR_FAILURE;
+  }
+
+  observerService->AddObserver(this, "xpcom-shutdown-threads", false);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsSound::Observe(nsISupports* aSubject, const char* aTopic,
+                 const char16_t* aData) {
+  if (!strcmp(aTopic, "xpcom-shutdown-threads")) {
+    PurgeLastSound();
+
+    if (mPlayerThread) {
+      mPlayerThread->Shutdown();
+      mPlayerThread = nullptr;
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsSound::Init() {
+  if (mInited) {
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(mPlayerThread, "player thread should not be null ");
+  // This call halts a sound if it was still playing.
+  // We have to use the sound library for something to make sure
+  // it is initialized.
+  // If we wait until the first sound is played, there will
+  // be a time lag as the library gets loaded.
+  // This should be done in player thread otherwise it will block main thread
+  // at the first time loading sound library.
+  mPlayerThread->Dispatch(
+      NS_NewRunnableFunction("nsSound::Init",
+                             []() {
+                               if (ShouldSuppressPlaySound()) {
+                                 return;
+                               }
+                               ::PlaySoundW(nullptr, nullptr, SND_PURGE);
+                             }),
+      NS_DISPATCH_NORMAL);
+
+  mInited = true;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsSound::PlayEventSound(uint32_t aEventId) {
+  MOZ_ASSERT(mPlayerThread, "player thread should not be null ");
+  PurgeLastSound();
+
+  const wchar_t* sound = nullptr;
+  switch (aEventId) {
+    case EVENT_NEW_MAIL_RECEIVED:
+      sound = L"MailBeep";
+      break;
+    case EVENT_ALERT_DIALOG_OPEN:
+      sound = L"SystemExclamation";
+      break;
+    case EVENT_CONFIRM_DIALOG_OPEN:
+      sound = L"SystemQuestion";
+      break;
+    case EVENT_MENU_EXECUTE:
+      sound = L"MenuCommand";
+      break;
+    case EVENT_MENU_POPUP:
+      sound = L"MenuPopup";
+      break;
+    case EVENT_EDITOR_MAX_LEN:
+      sound = L".Default";
+      break;
+    default:
+      // Win32 plays no sounds at NS_SYSSOUND_PROMPT_DIALOG and
+      // NS_SYSSOUND_SELECT_DIALOG.
+      return NS_OK;
+  }
+  NS_ASSERTION(sound, "sound is null");
+  MOZ_ASSERT(!mSoundPlayer, "mSoundPlayer should be null");
+  mSoundPlayer = new nsSoundPlayer(nsDependentString(sound));
+  MOZ_ASSERT(mSoundPlayer, "Could not create player");
+  nsresult rv = mPlayerThread->Dispatch(mSoundPlayer, NS_DISPATCH_NORMAL);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+  return NS_OK;
+}
diff --git a/widget/windows/nsSound.h b/widget/windows/nsSound.h
new file mode 100644
index 0000000000..d600b0873a
--- /dev/null
+++ b/widget/windows/nsSound.h
@@ -0,0 +1,47 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef __nsSound_h__
+#define __nsSound_h__
+
+#include "nsISound.h"
+#include "nsIObserver.h"
+#include "nsIStreamLoader.h"
+#include "nsCOMPtr.h"
+#include "mozilla/StaticPtr.h"
+
+class nsIThread;
+class nsIRunnable;
+
+class nsSound : public nsISound,
+                public nsIStreamLoaderObserver,
+                public nsIObserver
+
+{
+ public:
+  nsSound();
+  static already_AddRefed<nsISound> GetInstance();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSISOUND
+  NS_DECL_NSISTREAMLOADEROBSERVER
+  NS_DECL_NSIOBSERVER
+
+ private:
+  virtual ~nsSound();
+  void PurgeLastSound();
+
+ private:
+  nsresult CreatePlayerThread();
+
+  nsCOMPtr<nsIThread> mPlayerThread;
+  nsCOMPtr<nsIRunnable> mSoundPlayer;
+  bool mInited;
+
+  static mozilla::StaticRefPtr<nsISound> sInstance;
+};
+
+#endif /* __nsSound_h__ */
diff --git a/widget/windows/nsToolkit.cpp b/widget/windows/nsToolkit.cpp
new file mode 100644
index 0000000000..6eea9c958f
--- /dev/null
+++ b/widget/windows/nsToolkit.cpp
@@ -0,0 +1,69 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsToolkit.h"
+#include "nsAppShell.h"
+#include "nsWindow.h"
+#include "nsWidgetsCID.h"
+#include "prmon.h"
+#include "prtime.h"
+#include "nsComponentManagerUtils.h"
+#include <objbase.h>
+#include "WinUtils.h"
+
+#include "nsUXThemeData.h"
+
+// unknwn.h is needed to build with WIN32_LEAN_AND_MEAN
+#include <unknwn.h>
+
+using namespace mozilla::widget;
+
+nsToolkit* nsToolkit::gToolkit = nullptr;
+HINSTANCE nsToolkit::mDllInstance = 0;
+
+//-------------------------------------------------------------------------
+//
+// constructor
+//
+//-------------------------------------------------------------------------
+nsToolkit::nsToolkit() {
+  MOZ_COUNT_CTOR(nsToolkit);
+
+#if defined(MOZ_STATIC_COMPONENT_LIBS)
+  nsToolkit::Startup(GetModuleHandle(nullptr));
+#endif
+}
+
+//-------------------------------------------------------------------------
+//
+// destructor
+//
+//-------------------------------------------------------------------------
+nsToolkit::~nsToolkit() { MOZ_COUNT_DTOR(nsToolkit); }
+
+void nsToolkit::Startup(HMODULE hModule) {
+  nsToolkit::mDllInstance = hModule;
+  WinUtils::Initialize();
+}
+
+void nsToolkit::Shutdown() {
+  delete gToolkit;
+  gToolkit = nullptr;
+}
+
+//-------------------------------------------------------------------------
+//
+// Return the nsToolkit for the current thread.  If a toolkit does not
+// yet exist, then one will be created...
+//
+//-------------------------------------------------------------------------
+// static
+nsToolkit* nsToolkit::GetToolkit() {
+  if (!gToolkit) {
+    gToolkit = new nsToolkit();
+  }
+
+  return gToolkit;
+}
diff --git a/widget/windows/nsToolkit.h b/widget/windows/nsToolkit.h
new file mode 100644
index 0000000000..4be7bdb80a
--- /dev/null
+++ b/widget/windows/nsToolkit.h
@@ -0,0 +1,47 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsToolkit_h__
+#define nsToolkit_h__
+
+#include "nsdefs.h"
+
+#include "nsCOMPtr.h"
+#include <windows.h>
+
+// Avoid including windowsx.h to prevent macro pollution
+#ifndef GET_X_LPARAM
+#  define GET_X_LPARAM(pt) (short(LOWORD(pt)))
+#endif
+#ifndef GET_Y_LPARAM
+#  define GET_Y_LPARAM(pt) (short(HIWORD(pt)))
+#endif
+
+/**
+ * Wrapper around the thread running the message pump.
+ * The toolkit abstraction is necessary because the message pump must
+ * execute within the same thread that created the widget under Win32.
+ */
+
+class nsToolkit {
+ public:
+  nsToolkit();
+
+ private:
+  ~nsToolkit();
+
+ public:
+  static nsToolkit* GetToolkit();
+
+  static HINSTANCE mDllInstance;
+
+  static void Startup(HMODULE hModule);
+  static void Shutdown();
+
+ protected:
+  static nsToolkit* gToolkit;
+};
+
+#endif  // TOOLKIT_H
diff --git a/widget/windows/nsUXThemeConstants.h b/widget/windows/nsUXThemeConstants.h
new file mode 100644
index 0000000000..44ce9ab34e
--- /dev/null
+++ b/widget/windows/nsUXThemeConstants.h
@@ -0,0 +1,256 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsUXThemeConstants_h
+#define nsUXThemeConstants_h
+
+/*
+ * The following constants are used to determine how a widget is drawn using
+ * Windows' Theme API. For more information on theme parts and states see
+ * http://msdn.microsoft.com/en-us/library/bb773210(VS.85).aspx
+ */
+
+#include <vssym32.h>
+#include <vsstyle.h>
+
+#define THEME_COLOR 204
+#define THEME_FONT 210
+
+// Generic state constants
+#define TS_NORMAL 1
+#define TS_HOVER 2
+#define TS_ACTIVE 3
+#define TS_DISABLED 4
+#define TS_FOCUSED 5
+
+// These constants are reversed for the trackbar (scale) thumb
+#define TKP_FOCUSED 4
+#define TKP_DISABLED 5
+
+// Toolbarbutton constants
+#define TB_CHECKED 5
+#define TB_HOVER_CHECKED 6
+
+// Button constants
+#define BP_BUTTON 1
+#define BP_RADIO 2
+#define BP_CHECKBOX 3
+#define BP_GROUPBOX 4
+#define BP_Count 5
+
+// Textfield constants
+/* This is the EP_EDITTEXT part */
+#define TFP_TEXTFIELD 1
+#define TFP_EDITBORDER_NOSCROLL 6
+#define TFS_READONLY 6
+
+/* These are the state constants for the EDITBORDER parts */
+#define TFS_EDITBORDER_NORMAL 1
+#define TFS_EDITBORDER_HOVER 2
+#define TFS_EDITBORDER_FOCUSED 3
+#define TFS_EDITBORDER_DISABLED 4
+
+// Treeview/listbox constants
+#define TREEVIEW_BODY 1
+
+// Scrollbar constants
+#define SP_BUTTON 1
+#define SP_THUMBHOR 2
+#define SP_THUMBVERT 3
+#define SP_TRACKSTARTHOR 4
+#define SP_TRACKENDHOR 5
+#define SP_TRACKSTARTVERT 6
+#define SP_TRACKENDVERT 7
+#define SP_GRIPPERHOR 8
+#define SP_GRIPPERVERT 9
+
+// Implicit hover state.
+// BASE + 0 = UP, + 1 = DOWN, etc.
+#define SP_BUTTON_IMPLICIT_HOVER_BASE 17
+
+// Scale constants
+#define TKP_TRACK 1
+#define TKP_TRACKVERT 2
+#define TKP_THUMB 3
+#define TKP_THUMBBOTTOM 4
+#define TKP_THUMBTOP 5
+#define TKP_THUMBVERT 6
+#define TKP_THUMBLEFT 7
+#define TKP_THUMBRIGHT 8
+
+// Track state contstants
+#define TRS_NORMAL 1
+
+// Track vertical state constants
+#define TRVS_NORMAL 1
+
+// Spin constants
+#define SPNP_UP 1
+#define SPNP_DOWN 2
+
+// Tab constants
+#define TABP_TAB 4
+#define TABP_TAB_SELECTED 5
+#define TABP_PANELS 9
+#define TABP_PANEL 10
+
+// Tooltip constants
+#define TTP_STANDARD 1
+
+// Dropdown constants
+#define CBP_DROPMARKER 1
+#define CBP_DROPBORDER 4
+/* This is actually the 'READONLY' style */
+#define CBP_DROPFRAME 5
+#define CBP_DROPMARKER_VISTA 6
+
+// Menu Constants
+#define MENU_BARBACKGROUND 7
+#define MENU_BARITEM 8
+#define MENU_POPUPBACKGROUND 9
+#define MENU_POPUPBORDERS 10
+#define MENU_POPUPCHECK 11
+#define MENU_POPUPCHECKBACKGROUND 12
+#define MENU_POPUPGUTTER 13
+#define MENU_POPUPITEM 14
+#define MENU_POPUPSEPARATOR 15
+#define MENU_POPUPSUBMENU 16
+#define MENU_SYSTEMCLOSE 17
+#define MENU_SYSTEMMAXIMIZE 18
+#define MENU_SYSTEMMINIMIZE 19
+#define MENU_SYSTEMRESTORE 20
+
+#define MB_ACTIVE 1
+#define MB_INACTIVE 2
+
+#define MS_NORMAL 1
+#define MS_SELECTED 2
+#define MS_DEMOTED 3
+
+#define MBI_NORMAL 1
+#define MBI_HOT 2
+#define MBI_PUSHED 3
+#define MBI_DISABLED 4
+#define MBI_DISABLEDHOT 5
+#define MBI_DISABLEDPUSHED 6
+
+#define MC_CHECKMARKNORMAL 1
+#define MC_CHECKMARKDISABLED 2
+#define MC_BULLETNORMAL 3
+#define MC_BULLETDISABLED 4
+
+#define MCB_DISABLED 1
+#define MCB_NORMAL 2
+#define MCB_BITMAP 3
+
+#define MPI_NORMAL 1
+#define MPI_HOT 2
+#define MPI_DISABLED 3
+#define MPI_DISABLEDHOT 4
+
+#define MSM_NORMAL 1
+#define MSM_DISABLED 2
+
+// Rebar constants
+#define RP_BAND 3
+#define RP_BACKGROUND 6
+
+// Constants only found in new (98+, 2K+, XP+, etc.) Windows.
+#ifdef DFCS_HOT
+#  undef DFCS_HOT
+#endif
+#define DFCS_HOT 0x00001000
+
+#ifdef COLOR_MENUHILIGHT
+#  undef COLOR_MENUHILIGHT
+#endif
+#define COLOR_MENUHILIGHT 29
+
+#ifdef SPI_GETFLATMENU
+#  undef SPI_GETFLATMENU
+#endif
+#define SPI_GETFLATMENU 0x1022
+#ifndef SPI_GETMENUSHOWDELAY
+#  define SPI_GETMENUSHOWDELAY 106
+#endif  // SPI_GETMENUSHOWDELAY
+#ifndef SPI_GETCARETTIMEOUT
+#  define SPI_GETCARETTIMEOUT 0x2022
+#endif  // SPI_GETCARETTIMEOUT
+#ifndef WS_EX_LAYOUTRTL
+#  define WS_EX_LAYOUTRTL 0x00400000L  // Right to left mirroring
+#endif
+
+// Our extra constants for passing a little bit more info to the renderer.
+#define DFCS_RTL 0x00010000
+
+// Toolbar separator dimension which can't be gotten from Windows
+#define TB_SEPARATOR_HEIGHT 2
+
+namespace mozilla {
+namespace widget {
+namespace themeconst {
+
+// Pulled from sdk/include/vsstyle.h
+enum {
+  WP_CAPTION = 1,
+  WP_SMALLCAPTION = 2,
+  WP_MINCAPTION = 3,
+  WP_SMALLMINCAPTION = 4,
+  WP_MAXCAPTION = 5,
+  WP_SMALLMAXCAPTION = 6,
+  WP_FRAMELEFT = 7,
+  WP_FRAMERIGHT = 8,
+  WP_FRAMEBOTTOM = 9,
+  WP_SMALLFRAMELEFT = 10,
+  WP_SMALLFRAMERIGHT = 11,
+  WP_SMALLFRAMEBOTTOM = 12,
+  WP_SYSBUTTON = 13,
+  WP_MDISYSBUTTON = 14,
+  WP_MINBUTTON = 15,
+  WP_MDIMINBUTTON = 16,
+  WP_MAXBUTTON = 17,
+  WP_CLOSEBUTTON = 18,
+  WP_SMALLCLOSEBUTTON = 19,
+  WP_MDICLOSEBUTTON = 20,
+  WP_RESTOREBUTTON = 21,
+  WP_MDIRESTOREBUTTON = 22,
+  WP_HELPBUTTON = 23,
+  WP_MDIHELPBUTTON = 24,
+  WP_HORZSCROLL = 25,
+  WP_HORZTHUMB = 26,
+  WP_VERTSCROLL = 27,
+  WP_VERTTHUMB = 28,
+  WP_DIALOG = 29,
+  WP_CAPTIONSIZINGTEMPLATE = 30,
+  WP_SMALLCAPTIONSIZINGTEMPLATE = 31,
+  WP_FRAMELEFTSIZINGTEMPLATE = 32,
+  WP_SMALLFRAMELEFTSIZINGTEMPLATE = 33,
+  WP_FRAMERIGHTSIZINGTEMPLATE = 34,
+  WP_SMALLFRAMERIGHTSIZINGTEMPLATE = 35,
+  WP_FRAMEBOTTOMSIZINGTEMPLATE = 36,
+  WP_SMALLFRAMEBOTTOMSIZINGTEMPLATE = 37,
+  WP_FRAME = 38,
+  WP_Count
+};
+
+enum {
+  BS_NORMAL = 1,
+  BS_HOT = 2,
+  BS_PUSHED = 3,
+  BS_DISABLED = 4,
+  BS_INACTIVE = 5 /* undocumented, inactive caption button */
+};
+
+}  // namespace themeconst
+}  // namespace widget
+}  // namespace mozilla
+
+// If any theme part ends up having a value higher than WP_Count, this will
+// need to change.
+#define THEME_PART_DISTINCT_VALUE_COUNT mozilla::widget::themeconst::WP_Count
+
+#endif
diff --git a/widget/windows/nsUXThemeData.cpp b/widget/windows/nsUXThemeData.cpp
new file mode 100644
index 0000000000..b3f9e6fce9
--- /dev/null
+++ b/widget/windows/nsUXThemeData.cpp
@@ -0,0 +1,98 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/WindowsVersion.h"
+
+#include "nsUXThemeData.h"
+#include "nsDebug.h"
+#include "nsToolkit.h"
+#include "nsUXThemeConstants.h"
+#include "gfxWindowsPlatform.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+nsUXThemeData::ThemeHandle nsUXThemeData::sThemes[eUXNumClasses];
+
+nsUXThemeData::ThemeHandle::~ThemeHandle() { Close(); }
+
+void nsUXThemeData::ThemeHandle::OpenOnce(HWND aWindow, LPCWSTR aClassList) {
+  if (mHandle.isSome()) {
+    return;
+  }
+
+  mHandle = Some(OpenThemeData(aWindow, aClassList));
+}
+
+void nsUXThemeData::ThemeHandle::Close() {
+  if (mHandle.isNothing()) {
+    return;
+  }
+
+  if (HANDLE rawHandle = mHandle.extract()) {
+    CloseThemeData(rawHandle);
+  }
+}
+
+nsUXThemeData::ThemeHandle::operator HANDLE() {
+  return mHandle.valueOr(nullptr);
+}
+
+void nsUXThemeData::Invalidate() {
+  for (auto& theme : sThemes) {
+    theme.Close();
+  }
+}
+
+HANDLE
+nsUXThemeData::GetTheme(nsUXThemeClass cls) {
+  NS_ASSERTION(cls < eUXNumClasses, "Invalid theme class!");
+  sThemes[cls].OpenOnce(nullptr, GetClassName(cls));
+  return sThemes[cls];
+}
+
+const wchar_t* nsUXThemeData::GetClassName(nsUXThemeClass cls) {
+  switch (cls) {
+    case eUXButton:
+      return L"Button";
+    case eUXEdit:
+      return L"Edit";
+    case eUXRebar:
+      return L"Rebar";
+    case eUXToolbar:
+      return L"Toolbar";
+    case eUXProgress:
+      return L"Progress";
+    case eUXTab:
+      return L"Tab";
+    case eUXTrackbar:
+      return L"Trackbar";
+    case eUXCombobox:
+      return L"Combobox";
+    case eUXHeader:
+      return L"Header";
+    case eUXListview:
+      return L"Listview";
+    case eUXMenu:
+      return L"Menu";
+    default:
+      MOZ_ASSERT_UNREACHABLE("unknown uxtheme class");
+      return L"";
+  }
+}
+
+bool nsUXThemeData::sIsHighContrastOn = false;
+
+// static
+void nsUXThemeData::UpdateNativeThemeInfo() {
+  HIGHCONTRAST highContrastInfo;
+  highContrastInfo.cbSize = sizeof(HIGHCONTRAST);
+  sIsHighContrastOn =
+      SystemParametersInfo(SPI_GETHIGHCONTRAST, 0, &highContrastInfo, 0) &&
+      highContrastInfo.dwFlags & HCF_HIGHCONTRASTON;
+}
diff --git a/widget/windows/nsUXThemeData.h b/widget/windows/nsUXThemeData.h
new file mode 100644
index 0000000000..38be8b4484
--- /dev/null
+++ b/widget/windows/nsUXThemeData.h
@@ -0,0 +1,69 @@
+/* vim: se cin sw=2 ts=2 et : */
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef __UXThemeData_h__
+#define __UXThemeData_h__
+#include <windows.h>
+#include <uxtheme.h>
+
+#include "nscore.h"
+#include "mozilla/LookAndFeel.h"
+#include "mozilla/Maybe.h"
+#include "WinUtils.h"
+
+#include "nsWindowDefs.h"
+
+enum nsUXThemeClass {
+  eUXButton = 0,
+  eUXEdit,
+  eUXRebar,
+  eUXToolbar,
+  eUXProgress,
+  eUXTab,
+  eUXTrackbar,
+  eUXCombobox,
+  eUXHeader,
+  eUXListview,
+  eUXMenu,
+  eUXNumClasses
+};
+
+class nsUXThemeData {
+  // This class makes sure we don't attempt to open a theme if the previous
+  // loading attempt has failed because OpenThemeData is a heavy task and
+  // it's less likely that the API returns a different result.
+  class ThemeHandle final {
+    mozilla::Maybe<HANDLE> mHandle;
+
+   public:
+    ThemeHandle() = default;
+    ~ThemeHandle();
+
+    // Disallow copy and move
+    ThemeHandle(const ThemeHandle&) = delete;
+    ThemeHandle(ThemeHandle&&) = delete;
+    ThemeHandle& operator=(const ThemeHandle&) = delete;
+    ThemeHandle& operator=(ThemeHandle&&) = delete;
+
+    operator HANDLE();
+    void OpenOnce(HWND aWindow, LPCWSTR aClassList);
+    void Close();
+  };
+
+  static ThemeHandle sThemes[eUXNumClasses];
+  static const wchar_t* GetClassName(nsUXThemeClass);
+
+ public:
+  static bool sIsHighContrastOn;
+
+  static void Invalidate();
+  static HANDLE GetTheme(nsUXThemeClass cls);
+  static HMODULE GetThemeDLL();
+
+  static void UpdateNativeThemeInfo();
+  static bool IsHighContrastOn() { return sIsHighContrastOn; }
+};
+#endif  // __UXThemeData_h__
diff --git a/widget/windows/nsUserIdleServiceWin.cpp b/widget/windows/nsUserIdleServiceWin.cpp
new file mode 100644
index 0000000000..7cf957dffd
--- /dev/null
+++ b/widget/windows/nsUserIdleServiceWin.cpp
@@ -0,0 +1,20 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsUserIdleServiceWin.h"
+#include <windows.h>
+
+bool nsUserIdleServiceWin::PollIdleTime(uint32_t* aIdleTime) {
+  LASTINPUTINFO inputInfo;
+  inputInfo.cbSize = sizeof(inputInfo);
+  if (!::GetLastInputInfo(&inputInfo)) return false;
+
+  *aIdleTime =
+      SAFE_COMPARE_EVEN_WITH_WRAPPING(GetTickCount(), inputInfo.dwTime);
+
+  return true;
+}
diff --git a/widget/windows/nsUserIdleServiceWin.h b/widget/windows/nsUserIdleServiceWin.h
new file mode 100644
index 0000000000..f9a47c8df5
--- /dev/null
+++ b/widget/windows/nsUserIdleServiceWin.h
@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsUserIdleServiceWin_h__
+#define nsUserIdleServiceWin_h__
+
+#include "nsUserIdleService.h"
+#include "mozilla/AppShutdown.h"
+
+/* NOTE: Compare of GetTickCount() could overflow.  This corrects for
+ * overflow situations.
+ ***/
+#ifndef SAFE_COMPARE_EVEN_WITH_WRAPPING
+#  define SAFE_COMPARE_EVEN_WITH_WRAPPING(A, B) \
+    (((int)((long)A - (long)B) & 0xFFFFFFFF))
+#endif
+
+class nsUserIdleServiceWin : public nsUserIdleService {
+ public:
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(nsUserIdleServiceWin, nsUserIdleService)
+
+  bool PollIdleTime(uint32_t* aIdleTime) override;
+
+  static already_AddRefed<nsUserIdleServiceWin> GetInstance() {
+    RefPtr<nsUserIdleServiceWin> idleService =
+        nsUserIdleService::GetInstance().downcast<nsUserIdleServiceWin>();
+    if (!idleService) {
+      // Avoid late instantiation or resurrection during shutdown.
+      if (mozilla::AppShutdown::IsInOrBeyond(
+              mozilla::ShutdownPhase::AppShutdownConfirmed)) {
+        return nullptr;
+      }
+      idleService = new nsUserIdleServiceWin();
+    }
+
+    return idleService.forget();
+  }
+
+ protected:
+  nsUserIdleServiceWin() {}
+  virtual ~nsUserIdleServiceWin() {}
+};
+
+#endif  // nsUserIdleServiceWin_h__
diff --git a/widget/windows/nsWidgetFactory.cpp b/widget/windows/nsWidgetFactory.cpp
new file mode 100644
index 0000000000..47c7d021ed
--- /dev/null
+++ b/widget/windows/nsWidgetFactory.cpp
@@ -0,0 +1,60 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsWidgetFactory.h"
+
+#include "mozilla/Components.h"
+#include "nsISupports.h"
+#include "nsdefs.h"
+#include "nsWidgetsCID.h"
+#include "nsAppShell.h"
+#include "nsAppShellSingleton.h"
+#include "mozilla/WidgetUtils.h"
+#include "mozilla/widget/ScreenManager.h"
+#include "nsLookAndFeel.h"
+#include "WinMouseScrollHandler.h"
+#include "KeyboardLayout.h"
+#include "nsToolkit.h"
+
+// Modules that switch out based on the environment
+#include "nsXULAppAPI.h"
+// Desktop
+#include "nsFilePicker.h"  // needs to be included before other shobjidl.h includes
+#include "nsColorPicker.h"
+// Content processes
+#include "nsFilePickerProxy.h"
+
+// Clipboard
+#include "nsClipboardHelper.h"
+#include "nsClipboard.h"
+#include "HeadlessClipboard.h"
+
+#include "WindowsUIUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+NS_IMPL_COMPONENT_FACTORY(nsIClipboard) {
+  nsCOMPtr<nsIClipboard> inst;
+  if (gfxPlatform::IsHeadless()) {
+    inst = new HeadlessClipboard();
+  } else {
+    inst = new nsClipboard();
+  }
+  return inst.forget().downcast<nsISupports>();
+}
+
+nsresult nsWidgetWindowsModuleCtor() { return nsAppShellInit(); }
+
+void nsWidgetWindowsModuleDtor() {
+  // Shutdown all XP level widget classes.
+  WidgetUtils::Shutdown();
+
+  KeyboardLayout::Shutdown();
+  MouseScrollHandler::Shutdown();
+  nsLookAndFeel::Shutdown();
+  nsToolkit::Shutdown();
+  nsAppShellShutdown();
+}
diff --git a/widget/windows/nsWidgetFactory.h b/widget/windows/nsWidgetFactory.h
new file mode 100644
index 0000000000..41a39220e3
--- /dev/null
+++ b/widget/windows/nsWidgetFactory.h
@@ -0,0 +1,21 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef widget_windows_nsWidgetFactory_h
+#define widget_windows_nsWidgetFactory_h
+
+#include "nscore.h"
+#include "nsID.h"
+
+class nsISupports;
+
+nsresult nsAppShellConstructor(const nsIID& iid, void** result);
+
+nsresult nsWidgetWindowsModuleCtor();
+void nsWidgetWindowsModuleDtor();
+
+#endif  // defined widget_windows_nsWidgetFactory_h
diff --git a/widget/windows/nsWinGesture.cpp b/widget/windows/nsWinGesture.cpp
new file mode 100644
index 0000000000..8fd00b3ff0
--- /dev/null
+++ b/widget/windows/nsWinGesture.cpp
@@ -0,0 +1,388 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * nsWinGesture - Touch input handling for tablet displays.
+ */
+
+#include "nscore.h"
+#include "nsWinGesture.h"
+#include "nsUXThemeData.h"
+#include "mozilla/Logging.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/TouchEvents.h"
+#include "mozilla/dom/SimpleGestureEventBinding.h"
+#include "mozilla/dom/WheelEventBinding.h"
+
+#include <cmath>
+
+using namespace mozilla;
+using namespace mozilla::widget;
+
+extern mozilla::LazyLogModule gWindowsLog;
+
+static bool gEnableSingleFingerPanEvents = false;
+
+nsWinGesture::nsWinGesture()
+    : mPanActive(false),
+      mFeedbackActive(false),
+      mXAxisFeedback(false),
+      mYAxisFeedback(false),
+      mPanInertiaActive(false) {
+  (void)InitLibrary();
+  mPixelScrollOverflow = 0;
+}
+
+/* Load and shutdown */
+
+bool nsWinGesture::InitLibrary() {
+  // Check to see if we want single finger gesture input. Only do this once
+  // for the app so we don't have to look it up on every window create.
+  gEnableSingleFingerPanEvents =
+      Preferences::GetBool("gestures.enable_single_finger_input", false);
+
+  return true;
+}
+
+#define GCOUNT 5
+
+bool nsWinGesture::SetWinGestureSupport(
+    HWND hWnd, WidgetGestureNotifyEvent::PanDirection aDirection) {
+  GESTURECONFIG config[GCOUNT];
+
+  memset(&config, 0, sizeof(config));
+
+  config[0].dwID = GID_ZOOM;
+  config[0].dwWant = GC_ZOOM;
+  config[0].dwBlock = 0;
+
+  config[1].dwID = GID_ROTATE;
+  config[1].dwWant = GC_ROTATE;
+  config[1].dwBlock = 0;
+
+  config[2].dwID = GID_PAN;
+  config[2].dwWant = GC_PAN | GC_PAN_WITH_INERTIA | GC_PAN_WITH_GUTTER;
+  config[2].dwBlock = GC_PAN_WITH_SINGLE_FINGER_VERTICALLY |
+                      GC_PAN_WITH_SINGLE_FINGER_HORIZONTALLY;
+
+  if (gEnableSingleFingerPanEvents) {
+    if (aDirection == WidgetGestureNotifyEvent::ePanVertical ||
+        aDirection == WidgetGestureNotifyEvent::ePanBoth) {
+      config[2].dwWant |= GC_PAN_WITH_SINGLE_FINGER_VERTICALLY;
+      config[2].dwBlock -= GC_PAN_WITH_SINGLE_FINGER_VERTICALLY;
+    }
+
+    if (aDirection == WidgetGestureNotifyEvent::ePanHorizontal ||
+        aDirection == WidgetGestureNotifyEvent::ePanBoth) {
+      config[2].dwWant |= GC_PAN_WITH_SINGLE_FINGER_HORIZONTALLY;
+      config[2].dwBlock -= GC_PAN_WITH_SINGLE_FINGER_HORIZONTALLY;
+    }
+  }
+
+  config[3].dwWant = GC_TWOFINGERTAP;
+  config[3].dwID = GID_TWOFINGERTAP;
+  config[3].dwBlock = 0;
+
+  config[4].dwWant = GC_PRESSANDTAP;
+  config[4].dwID = GID_PRESSANDTAP;
+  config[4].dwBlock = 0;
+
+  return SetGestureConfig(hWnd, 0, GCOUNT, (PGESTURECONFIG)&config,
+                          sizeof(GESTURECONFIG));
+}
+
+/* Helpers */
+
+bool nsWinGesture::IsPanEvent(LPARAM lParam) {
+  GESTUREINFO gi;
+
+  ZeroMemory(&gi, sizeof(GESTUREINFO));
+  gi.cbSize = sizeof(GESTUREINFO);
+
+  BOOL result = GetGestureInfo((HGESTUREINFO)lParam, &gi);
+  if (!result) return false;
+
+  if (gi.dwID == GID_PAN) return true;
+
+  return false;
+}
+
+/* Gesture event processing */
+
+bool nsWinGesture::ProcessGestureMessage(HWND hWnd, WPARAM wParam,
+                                         LPARAM lParam,
+                                         WidgetSimpleGestureEvent& evt) {
+  GESTUREINFO gi;
+
+  ZeroMemory(&gi, sizeof(GESTUREINFO));
+  gi.cbSize = sizeof(GESTUREINFO);
+
+  BOOL result = GetGestureInfo((HGESTUREINFO)lParam, &gi);
+  if (!result) return false;
+
+  // The coordinates of this event
+  nsPointWin coord;
+  coord = gi.ptsLocation;
+  coord.ScreenToClient(hWnd);
+
+  evt.mRefPoint = LayoutDeviceIntPoint(coord.x, coord.y);
+
+  // Multiple gesture can occur at the same time so gesture state
+  // info can't be shared.
+  switch (gi.dwID) {
+    case GID_BEGIN:
+    case GID_END:
+      // These should always fall through to DefWndProc
+      return false;
+      break;
+
+    case GID_ZOOM: {
+      if (gi.dwFlags & GF_BEGIN) {
+        // Send a zoom start event
+
+        // The low 32 bits are the distance in pixels.
+        mZoomIntermediate = (float)gi.ullArguments;
+
+        evt.mMessage = eMagnifyGestureStart;
+        evt.mDelta = 0.0;
+      } else if (gi.dwFlags & GF_END) {
+        // Send a zoom end event, the delta is the change
+        // in touch points.
+        evt.mMessage = eMagnifyGesture;
+        // (positive for a "zoom in")
+        evt.mDelta = -1.0 * (mZoomIntermediate - (float)gi.ullArguments);
+        mZoomIntermediate = (float)gi.ullArguments;
+      } else {
+        // Send a zoom intermediate event, the delta is the change
+        // in touch points.
+        evt.mMessage = eMagnifyGestureUpdate;
+        // (positive for a "zoom in")
+        evt.mDelta = -1.0 * (mZoomIntermediate - (float)gi.ullArguments);
+        mZoomIntermediate = (float)gi.ullArguments;
+      }
+    } break;
+
+    case GID_ROTATE: {
+      // Send a rotate start event
+      double radians = 0.0;
+
+      // On GF_BEGIN, ullArguments contains the absolute rotation at the
+      // start of the gesture. In later events it contains the offset from
+      // the start angle.
+      if (gi.ullArguments != 0)
+        radians = GID_ROTATE_ANGLE_FROM_ARGUMENT(gi.ullArguments);
+
+      double degrees = -1 * radians * (180 / M_PI);
+
+      if (gi.dwFlags & GF_BEGIN) {
+        // At some point we should pass the initial angle in
+        // along with delta. It's useful.
+        degrees = mRotateIntermediate = 0.0;
+      }
+
+      evt.mDirection = 0;
+      evt.mDelta = degrees - mRotateIntermediate;
+      mRotateIntermediate = degrees;
+
+      if (evt.mDelta > 0) {
+        evt.mDirection =
+            dom::SimpleGestureEvent_Binding::ROTATION_COUNTERCLOCKWISE;
+      } else if (evt.mDelta < 0) {
+        evt.mDirection = dom::SimpleGestureEvent_Binding::ROTATION_CLOCKWISE;
+      }
+
+      if (gi.dwFlags & GF_BEGIN) {
+        evt.mMessage = eRotateGestureStart;
+      } else if (gi.dwFlags & GF_END) {
+        evt.mMessage = eRotateGesture;
+      } else {
+        evt.mMessage = eRotateGestureUpdate;
+      }
+    } break;
+
+    case GID_TWOFINGERTAP:
+      // Normally maps to "restore" from whatever you may have recently changed.
+      // A simple double click.
+      evt.mMessage = eTapGesture;
+      evt.mClickCount = 1;
+      break;
+
+    case GID_PRESSANDTAP:
+      // Two finger right click. Defaults to right click if it falls through.
+      evt.mMessage = ePressTapGesture;
+      evt.mClickCount = 1;
+      break;
+  }
+
+  return true;
+}
+
+bool nsWinGesture::ProcessPanMessage(HWND hWnd, WPARAM wParam, LPARAM lParam) {
+  GESTUREINFO gi;
+
+  ZeroMemory(&gi, sizeof(GESTUREINFO));
+  gi.cbSize = sizeof(GESTUREINFO);
+
+  BOOL result = GetGestureInfo((HGESTUREINFO)lParam, &gi);
+  if (!result) return false;
+
+  // The coordinates of this event
+  nsPointWin coord;
+  coord = mPanRefPoint = gi.ptsLocation;
+  // We want screen coordinates in our local offsets as client coordinates will
+  // change when feedback is taking place. Gui events though require client
+  // coordinates.
+  mPanRefPoint.ScreenToClient(hWnd);
+
+  switch (gi.dwID) {
+    case GID_BEGIN:
+    case GID_END:
+      // These should always fall through to DefWndProc
+      return false;
+      break;
+
+    // Setup pixel scroll events for both axis
+    case GID_PAN: {
+      if (gi.dwFlags & GF_BEGIN) {
+        mPanIntermediate = coord;
+        mPixelScrollDelta = 0;
+        mPanActive = true;
+        mPanInertiaActive = false;
+      } else {
+#ifdef DBG_jimm
+        int32_t deltaX = mPanIntermediate.x - coord.x;
+        int32_t deltaY = mPanIntermediate.y - coord.y;
+        MOZ_LOG(gWindowsLog, LogLevel::Info,
+                ("coordX=%d coordY=%d deltaX=%d deltaY=%d x:%d y:%d\n", coord.x,
+                 coord.y, deltaX, deltaY, mXAxisFeedback, mYAxisFeedback));
+#endif
+
+        mPixelScrollDelta.x = mPanIntermediate.x - coord.x;
+        mPixelScrollDelta.y = mPanIntermediate.y - coord.y;
+        mPanIntermediate = coord;
+
+        if (gi.dwFlags & GF_INERTIA) mPanInertiaActive = true;
+
+        if (gi.dwFlags & GF_END) {
+          mPanActive = false;
+          mPanInertiaActive = false;
+          PanFeedbackFinalize(hWnd, true);
+        }
+      }
+    } break;
+  }
+  return true;
+}
+
+inline bool TestTransition(int32_t a, int32_t b) {
+  // If a is zero, overflow is zero, implying the cursor has moved back to the
+  // start position. If b is zero, cached overscroll is zero, implying feedback
+  // just begun.
+  if (a == 0 || b == 0) return true;
+  // Test for different signs.
+  return (a < 0) == (b < 0);
+}
+
+void nsWinGesture::UpdatePanFeedbackX(HWND hWnd, int32_t scrollOverflow,
+                                      bool& endFeedback) {
+  // If scroll overflow was returned indicating we panned past the bounds of
+  // the scrollable view port, start feeback.
+  if (scrollOverflow != 0) {
+    if (!mFeedbackActive) {
+      BeginPanningFeedback(hWnd);
+      mFeedbackActive = true;
+    }
+    endFeedback = false;
+    mXAxisFeedback = true;
+    return;
+  }
+
+  if (mXAxisFeedback) {
+    int32_t newOverflow = mPixelScrollOverflow.x - mPixelScrollDelta.x;
+
+    // Detect a reverse transition past the starting drag point. This tells us
+    // the user has panned all the way back so we can stop providing feedback
+    // for this axis.
+    if (!TestTransition(newOverflow, mPixelScrollOverflow.x) ||
+        newOverflow == 0)
+      return;
+
+    // Cache the total over scroll in pixels.
+    mPixelScrollOverflow.x = newOverflow;
+    endFeedback = false;
+  }
+}
+
+void nsWinGesture::UpdatePanFeedbackY(HWND hWnd, int32_t scrollOverflow,
+                                      bool& endFeedback) {
+  // If scroll overflow was returned indicating we panned past the bounds of
+  // the scrollable view port, start feeback.
+  if (scrollOverflow != 0) {
+    if (!mFeedbackActive) {
+      BeginPanningFeedback(hWnd);
+      mFeedbackActive = true;
+    }
+    endFeedback = false;
+    mYAxisFeedback = true;
+    return;
+  }
+
+  if (mYAxisFeedback) {
+    int32_t newOverflow = mPixelScrollOverflow.y - mPixelScrollDelta.y;
+
+    // Detect a reverse transition past the starting drag point. This tells us
+    // the user has panned all the way back so we can stop providing feedback
+    // for this axis.
+    if (!TestTransition(newOverflow, mPixelScrollOverflow.y) ||
+        newOverflow == 0)
+      return;
+
+    // Cache the total over scroll in pixels.
+    mPixelScrollOverflow.y = newOverflow;
+    endFeedback = false;
+  }
+}
+
+void nsWinGesture::PanFeedbackFinalize(HWND hWnd, bool endFeedback) {
+  if (!mFeedbackActive) return;
+
+  if (endFeedback) {
+    mFeedbackActive = false;
+    mXAxisFeedback = false;
+    mYAxisFeedback = false;
+    mPixelScrollOverflow = 0;
+    EndPanningFeedback(hWnd, TRUE);
+    return;
+  }
+
+  UpdatePanningFeedback(hWnd, mPixelScrollOverflow.x, mPixelScrollOverflow.y,
+                        mPanInertiaActive);
+}
+
+bool nsWinGesture::PanDeltaToPixelScroll(WidgetWheelEvent& aWheelEvent) {
+  aWheelEvent.mDeltaX = aWheelEvent.mDeltaY = aWheelEvent.mDeltaZ = 0.0;
+  aWheelEvent.mLineOrPageDeltaX = aWheelEvent.mLineOrPageDeltaY = 0;
+
+  aWheelEvent.mRefPoint = LayoutDeviceIntPoint(mPanRefPoint.x, mPanRefPoint.y);
+  aWheelEvent.mDeltaMode = dom::WheelEvent_Binding::DOM_DELTA_PIXEL;
+  aWheelEvent.mScrollType = WidgetWheelEvent::SCROLL_SYNCHRONOUSLY;
+  aWheelEvent.mIsNoLineOrPageDelta = true;
+
+  aWheelEvent.mOverflowDeltaX = 0.0;
+  aWheelEvent.mOverflowDeltaY = 0.0;
+
+  // Don't scroll the view if we are currently at a bounds, or, if we are
+  // panning back from a max feedback position. This keeps the original drag
+  // point constant.
+  if (!mXAxisFeedback) {
+    aWheelEvent.mDeltaX = mPixelScrollDelta.x;
+  }
+  if (!mYAxisFeedback) {
+    aWheelEvent.mDeltaY = mPixelScrollDelta.y;
+  }
+
+  return (aWheelEvent.mDeltaX != 0 || aWheelEvent.mDeltaY != 0);
+}
diff --git a/widget/windows/nsWinGesture.h b/widget/windows/nsWinGesture.h
new file mode 100644
index 0000000000..040b460da9
--- /dev/null
+++ b/widget/windows/nsWinGesture.h
@@ -0,0 +1,91 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WinGesture_h__
+#define WinGesture_h__
+
+/*
+ * nsWinGesture - Touch input handling for tablet displays.
+ */
+
+#include "nsdefs.h"
+#include <winuser.h>
+#include <tpcshrd.h>
+#include "nsPoint.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/TouchEvents.h"
+
+// WM_TABLET_QUERYSYSTEMGESTURESTATUS return values
+#define TABLET_ROTATE_GESTURE_ENABLE 0x02000000
+
+class nsPointWin : public nsIntPoint {
+ public:
+  nsPointWin& operator=(const POINTS& aPoint) {
+    x = aPoint.x;
+    y = aPoint.y;
+    return *this;
+  }
+  nsPointWin& operator=(const POINT& aPoint) {
+    x = aPoint.x;
+    y = aPoint.y;
+    return *this;
+  }
+  nsPointWin& operator=(int val) {
+    x = y = val;
+    return *this;
+  }
+  void ScreenToClient(HWND hWnd) {
+    POINT tmp;
+    tmp.x = x;
+    tmp.y = y;
+    ::ScreenToClient(hWnd, &tmp);
+    *this = tmp;
+  }
+};
+
+class nsWinGesture {
+ public:
+  nsWinGesture();
+
+ public:
+  bool SetWinGestureSupport(
+      HWND hWnd, mozilla::WidgetGestureNotifyEvent::PanDirection aDirection);
+  bool ShutdownWinGestureSupport();
+
+  // Simple gesture process
+  bool ProcessGestureMessage(HWND hWnd, WPARAM wParam, LPARAM lParam,
+                             mozilla::WidgetSimpleGestureEvent& evt);
+
+  // Pan processing
+  bool IsPanEvent(LPARAM lParam);
+  bool ProcessPanMessage(HWND hWnd, WPARAM wParam, LPARAM lParam);
+  bool PanDeltaToPixelScroll(mozilla::WidgetWheelEvent& aWheelEvent);
+  void UpdatePanFeedbackX(HWND hWnd, int32_t scrollOverflow, bool& endFeedback);
+  void UpdatePanFeedbackY(HWND hWnd, int32_t scrollOverflow, bool& endFeedback);
+  void PanFeedbackFinalize(HWND hWnd, bool endFeedback);
+
+ private:
+  // Delay load info
+  bool InitLibrary();
+
+  // Pan and feedback state
+  nsPointWin mPanIntermediate;
+  nsPointWin mPanRefPoint;
+  nsPointWin mPixelScrollDelta;
+  bool mPanActive;
+  bool mFeedbackActive;
+  bool mXAxisFeedback;
+  bool mYAxisFeedback;
+  bool mPanInertiaActive;
+  nsPointWin mPixelScrollOverflow;
+
+  // Zoom state
+  double mZoomIntermediate;
+
+  // Rotate state
+  double mRotateIntermediate;
+};
+
+#endif /* WinGesture_h__ */
diff --git a/widget/windows/nsWindow.cpp b/widget/windows/nsWindow.cpp
new file mode 100644
index 0000000000..1a8646d620
--- /dev/null
+++ b/widget/windows/nsWindow.cpp
@@ -0,0 +1,9000 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sts=2 sw=2 et cin: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * nsWindow - Native window management and event handling.
+ *
+ * nsWindow is organized into a set of major blocks and
+ * block subsections. The layout is as follows:
+ *
+ *  Includes
+ *  Variables
+ *  nsIWidget impl.
+ *     nsIWidget methods and utilities
+ *  nsSwitchToUIThread impl.
+ *     nsSwitchToUIThread methods and utilities
+ *  Moz events
+ *     Event initialization
+ *     Event dispatching
+ *  Native events
+ *     Wndproc(s)
+ *     Event processing
+ *     OnEvent event handlers
+ *  IME management and accessibility
+ *  Transparency
+ *  Popup hook handling
+ *  Misc. utilities
+ *  Child window impl.
+ *
+ * Search for "BLOCK:" to find major blocks.
+ * Search for "SECTION:" to find specific sections.
+ *
+ * Blocks should be split out into separate files if they
+ * become unmanageable.
+ *
+ * Notable related sources:
+ *
+ *  nsWindowDefs.h     - Definitions, macros, structs, enums
+ *                       and general setup.
+ *  nsWindowDbg.h/.cpp - Debug related code and directives.
+ *  nsWindowGfx.h/.cpp - Graphics and painting.
+ *
+ */
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: Includes
+ **
+ ** Include headers.
+ **
+ **************************************************************
+ **************************************************************/
+
+#include "gfx2DGlue.h"
+#include "gfxEnv.h"
+#include "gfxPlatform.h"
+
+#include "mozilla/AppShutdown.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/Likely.h"
+#include "mozilla/PreXULSkeletonUI.h"
+#include "mozilla/Logging.h"
+#include "mozilla/MathAlgorithms.h"
+#include "mozilla/MiscEvents.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/StaticPrefs_browser.h"
+#include "mozilla/SwipeTracker.h"
+#include "mozilla/TouchEvents.h"
+#include "mozilla/TimeStamp.h"
+
+#include "mozilla/ipc/MessageChannel.h"
+#include <algorithm>
+#include <limits>
+
+#include "mozilla/widget/WinMessages.h"
+#include "nsWindow.h"
+#include "nsWindowTaskbarConcealer.h"
+#include "nsAppRunner.h"
+
+#include <shellapi.h>
+#include <windows.h>
+#include <wtsapi32.h>
+#include <process.h>
+#include <commctrl.h>
+#include <dbt.h>
+#include <unknwn.h>
+#include <psapi.h>
+#include <rpc.h>
+#include <propvarutil.h>
+#include <propkey.h>
+
+#include "mozilla/Logging.h"
+#include "prtime.h"
+#include "prenv.h"
+
+#include "mozilla/WidgetTraceEvent.h"
+#include "nsContentUtils.h"
+#include "nsISupportsPrimitives.h"
+#include "nsITheme.h"
+#include "nsIObserverService.h"
+#include "nsIScreenManager.h"
+#include "imgIContainer.h"
+#include "nsIFile.h"
+#include "nsIRollupListener.h"
+#include "nsIClipboard.h"
+#include "WinMouseScrollHandler.h"
+#include "nsFontMetrics.h"
+#include "nsIFontEnumerator.h"
+#include "nsFont.h"
+#include "nsRect.h"
+#include "nsThreadUtils.h"
+#include "nsNativeCharsetUtils.h"
+#include "nsGkAtoms.h"
+#include "nsCRT.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsWidgetsCID.h"
+#include "nsTHashtable.h"
+#include "nsHashKeys.h"
+#include "nsString.h"
+#include "mozilla/Components.h"
+#include "nsNativeThemeWin.h"
+#include "nsXULPopupManager.h"
+#include "nsWindowsDllInterceptor.h"
+#include "nsLayoutUtils.h"
+#include "nsView.h"
+#include "nsWindowGfx.h"
+#include "gfxWindowsPlatform.h"
+#include "gfxDWriteFonts.h"
+#include "nsPrintfCString.h"
+#include "mozilla/Preferences.h"
+#include "SystemTimeConverter.h"
+#include "WinTaskbar.h"
+#include "WidgetUtils.h"
+#include "WinWindowOcclusionTracker.h"
+#include "nsIWidgetListener.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/MouseEventBinding.h"
+#include "mozilla/dom/Touch.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/GPUProcessManager.h"
+#include "mozilla/intl/LocaleService.h"
+#include "mozilla/layers/WebRenderLayerManager.h"
+#include "mozilla/WindowsVersion.h"
+#include "mozilla/TextEvents.h"  // For WidgetKeyboardEvent
+#include "mozilla/TextEventDispatcherListener.h"
+#include "mozilla/widget/nsAutoRollup.h"
+#include "mozilla/widget/PlatformWidgetTypes.h"
+#include "mozilla/widget/Screen.h"
+#include "nsStyleConsts.h"
+#include "nsBidiKeyboard.h"
+#include "nsStyleConsts.h"
+#include "gfxConfig.h"
+#include "InProcessWinCompositorWidget.h"
+#include "InputDeviceUtils.h"
+#include "ScreenHelperWin.h"
+#include "mozilla/StaticPrefs_apz.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/StaticPrefs_gfx.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/StaticPrefs_ui.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsNativeAppSupportWin.h"
+#include "mozilla/browser/NimbusFeatures.h"
+
+#include "nsIGfxInfo.h"
+#include "nsUXThemeConstants.h"
+#include "KeyboardLayout.h"
+#include "nsNativeDragTarget.h"
+#include <mmsystem.h>  // needed for WIN32_LEAN_AND_MEAN
+#include <zmouse.h>
+#include <richedit.h>
+
+#if defined(ACCESSIBILITY)
+
+#  ifdef DEBUG
+#    include "mozilla/a11y/Logging.h"
+#  endif
+
+#  include "oleidl.h"
+#  include <winuser.h>
+#  include "nsAccessibilityService.h"
+#  include "mozilla/a11y/DocAccessible.h"
+#  include "mozilla/a11y/LazyInstantiator.h"
+#  include "mozilla/a11y/Platform.h"
+#  if !defined(WINABLEAPI)
+#    include <winable.h>
+#  endif  // !defined(WINABLEAPI)
+#endif    // defined(ACCESSIBILITY)
+
+#include "WindowsUIUtils.h"
+
+#include "nsWindowDefs.h"
+
+#include "nsCrashOnException.h"
+
+#include "nsIContent.h"
+
+#include "mozilla/BackgroundHangMonitor.h"
+#include "WinIMEHandler.h"
+
+#include "npapi.h"
+
+#include <d3d11.h>
+
+// ERROR from wingdi.h (below) gets undefined by some code.
+// #define ERROR               0
+// #define RGN_ERROR ERROR
+#define ERROR 0
+
+#if !defined(SM_CONVERTIBLESLATEMODE)
+#  define SM_CONVERTIBLESLATEMODE 0x2003
+#endif
+
+#include "mozilla/gfx/DeviceManagerDx.h"
+#include "mozilla/layers/APZInputBridge.h"
+#include "mozilla/layers/InputAPZContext.h"
+#include "mozilla/layers/KnowsCompositor.h"
+#include "InputData.h"
+
+#include "mozilla/TaskController.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/webrender/WebRenderAPI.h"
+#include "mozilla/layers/IAPZCTreeManager.h"
+
+#include "DirectManipulationOwner.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::gfx;
+using namespace mozilla::layers;
+using namespace mozilla::widget;
+using namespace mozilla::plugins;
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: Variables
+ **
+ ** nsWindow Class static initializations and global variables.
+ **
+ **************************************************************
+ **************************************************************/
+
+/**************************************************************
+ *
+ * SECTION: nsWindow statics
+ *
+ **************************************************************/
+static const wchar_t kUser32LibName[] = L"user32.dll";
+
+uint32_t nsWindow::sInstanceCount = 0;
+bool nsWindow::sIsOleInitialized = false;
+nsIWidget::Cursor nsWindow::sCurrentCursor = {};
+nsWindow* nsWindow::sCurrentWindow = nullptr;
+bool nsWindow::sJustGotDeactivate = false;
+bool nsWindow::sJustGotActivate = false;
+bool nsWindow::sIsInMouseCapture = false;
+
+// Urgent-message reentrancy depth for the static `WindowProc` callback.
+//
+// Three unfortunate facts collide:
+//
+// 𝛼) Some messages must be processed promptly. If not, Windows will leave the
+//    receiving window in an intermediate, and potentially unusable, state until
+//    the WindowProc invocation that is handling it returns.
+//
+// 𝛽) Some messages have indefinitely long processing time. These are mostly
+//    messages which may cause us to enter a nested modal loop (via
+//    `SpinEventLoopUntil` or similar).
+//
+// 𝛾) Sometimes, messages skip the queue entirely. Our `WindowProc` may be
+//    reentrantly reinvoked from the kernel while we're blocking _on_ the
+//    kernel, even briefly, during processing of other messages. (Relevant
+//    search term: `KeUserModeCallback`.)
+//
+// The nightmare scenario, then, is that during processing of an 𝛼-message, we
+// briefly become blocked (e.g., by calling `::SendMessageW()`), and the kernel
+// takes that opportunity to use 𝛾 to hand us a 𝛽-message. (Concretely, see
+// bug 1842170.)
+//
+// There is little we can do to prevent the first half of this scenario. 𝛼) and
+// 𝛾) are effectively immutable facts of Windows, and we sometimes legitimately
+// need to make blocking calls to process 𝛼-messages. (We may not even be aware
+// that we're making such calls, if they're undocumented implementation details
+// of another API.)
+//
+// In an ideal world, WindowProc would always return promptly (or at least in
+// bounded time), and 𝛽-messages would not _per se_ exist; long-running modal
+// states would instead be implemented in async fashion. In practice, that's far
+// easier said than done -- replacing existing uses of `SpinEventLoopUntil` _et
+// al._ with asynchronous mechanisms is a collection of mostly-unrelated cross-
+// cutting architectural tasks, each of potentially unbounded scope. For now,
+// and for the foreseeable future, we're stuck with them.
+//
+// We therefore simply punt. More specifically: if a known 𝛽-message jumps the
+// queue to come in while we're in the middle of processing a known 𝛼-message,
+// we:
+//  * properly queue the message for processing later;
+//  * respond to the 𝛽-message as though we actually had processed it; and
+//  * just hope that it can wait until we get around to it.
+//
+// The word "known" requires a bit of justification. There is no canonical set
+// of 𝛼-messages, nor is the set of 𝛽-messages fixed (or even demarcable). We
+// can't safely assume that all messages are 𝛼-messages, as that could cause
+// 𝛽-messages to be arbitrarily and surprisingly delayed whenever any nested
+// event loop is active. We also can't assume all messages are 𝛽-messages,
+// since one 𝛼-message jumping the queue while processing another 𝛼-message is
+// part of normal and required operation for windowed Windows applications.
+//
+// So we simply add messages to those sets as we identify them. (Or, preferably,
+// rework the 𝛽-message's handling to make it no longer 𝛽. But see above.)
+//
+// ---
+//
+// The actual value of `sDepth` is the number of active invocations of
+// `WindowProc` that are processing known 𝛼-messages.
+size_t nsWindow::WndProcUrgentInvocation::sDepth = 0;
+
+// Hook Data Members for Dropdowns. sProcessHook Tells the
+// hook methods whether they should be processing the hook
+// messages.
+HHOOK nsWindow::sMsgFilterHook = nullptr;
+HHOOK nsWindow::sCallProcHook = nullptr;
+HHOOK nsWindow::sCallMouseHook = nullptr;
+bool nsWindow::sProcessHook = false;
+UINT nsWindow::sRollupMsgId = 0;
+HWND nsWindow::sRollupMsgWnd = nullptr;
+UINT nsWindow::sHookTimerId = 0;
+
+// Used to prevent dispatching mouse events that do not originate from user
+// input.
+POINT nsWindow::sLastMouseMovePoint = {0};
+
+bool nsWindow::sIsRestoringSession = false;
+
+bool nsWindow::sTouchInjectInitialized = false;
+InjectTouchInputPtr nsWindow::sInjectTouchFuncPtr;
+
+static SystemTimeConverter<DWORD>& TimeConverter() {
+  static SystemTimeConverter<DWORD> timeConverterSingleton;
+  return timeConverterSingleton;
+}
+
+// Global event hook for window cloaking. Never deregistered.
+//  - `Nothing` if not yet set.
+//  - `Some(nullptr)` if no attempt should be made to set it.
+static mozilla::Maybe<HWINEVENTHOOK> sWinCloakEventHook = Nothing();
+static mozilla::LazyLogModule sCloakingLog("DWMCloaking");
+
+namespace mozilla {
+
+class CurrentWindowsTimeGetter {
+ public:
+  explicit CurrentWindowsTimeGetter(HWND aWnd) : mWnd(aWnd) {}
+
+  DWORD GetCurrentTime() const { return ::GetTickCount(); }
+
+  void GetTimeAsyncForPossibleBackwardsSkew(const TimeStamp& aNow) {
+    DWORD currentTime = GetCurrentTime();
+    if (sBackwardsSkewStamp && currentTime == sLastPostTime) {
+      // There's already one inflight with this timestamp. Don't
+      // send a duplicate.
+      return;
+    }
+    sBackwardsSkewStamp = Some(aNow);
+    sLastPostTime = currentTime;
+    static_assert(sizeof(WPARAM) >= sizeof(DWORD),
+                  "Can't fit a DWORD in a WPARAM");
+    ::PostMessage(mWnd, MOZ_WM_SKEWFIX, sLastPostTime, 0);
+  }
+
+  static bool GetAndClearBackwardsSkewStamp(DWORD aPostTime,
+                                            TimeStamp* aOutSkewStamp) {
+    if (aPostTime != sLastPostTime) {
+      // The SKEWFIX message is stale; we've sent a new one since then.
+      // Ignore this one.
+      return false;
+    }
+    MOZ_ASSERT(sBackwardsSkewStamp);
+    *aOutSkewStamp = sBackwardsSkewStamp.value();
+    sBackwardsSkewStamp = Nothing();
+    return true;
+  }
+
+ private:
+  static Maybe<TimeStamp> sBackwardsSkewStamp;
+  static DWORD sLastPostTime;
+  HWND mWnd;
+};
+
+Maybe<TimeStamp> CurrentWindowsTimeGetter::sBackwardsSkewStamp;
+DWORD CurrentWindowsTimeGetter::sLastPostTime = 0;
+
+}  // namespace mozilla
+
+/**************************************************************
+ *
+ * SECTION: globals variables
+ *
+ **************************************************************/
+
+static const char* sScreenManagerContractID =
+    "@mozilla.org/gfx/screenmanager;1";
+
+extern mozilla::LazyLogModule gWindowsLog;
+
+static NS_DEFINE_CID(kCClipboardCID, NS_CLIPBOARD_CID);
+
+// General purpose user32.dll hook object
+static WindowsDllInterceptor sUser32Intercept;
+
+// When the client area is extended out into the default window frame area,
+// this is the minimum amount of space along the edge of resizable windows
+// we will always display a resize cursor in, regardless of the underlying
+// content.
+static const int32_t kResizableBorderMinSize = 3;
+
+// Getting this object from the window server can be expensive. Keep it
+// around, also get it off the main thread. (See bug 1640852)
+StaticRefPtr<IVirtualDesktopManager> gVirtualDesktopManager;
+static bool gInitializedVirtualDesktopManager = false;
+
+// We should never really try to accelerate windows bigger than this. In some
+// cases this might lead to no D3D9 acceleration where we could have had it
+// but D3D9 does not reliably report when it supports bigger windows. 8192
+// is as safe as we can get, we know at least D3D10 hardware always supports
+// this, other hardware we expect to report correctly in D3D9.
+#define MAX_ACCELERATED_DIMENSION 8192
+
+// On window open (as well as after), Windows has an unfortunate habit of
+// sending rather a lot of WM_NCHITTEST messages. Because we have to do point
+// to DOM target conversions for these, we cache responses for a given
+// coordinate this many milliseconds:
+#define HITTEST_CACHE_LIFETIME_MS 50
+
+#if defined(ACCESSIBILITY)
+
+namespace mozilla {
+
+/**
+ * Windows touchscreen code works by setting a global WH_GETMESSAGE hook and
+ * injecting tiptsf.dll. The touchscreen process then posts registered messages
+ * to our main thread. The tiptsf hook picks up those registered messages and
+ * uses them as commands, some of which call into UIA, which then calls into
+ * MSAA, which then sends WM_GETOBJECT to us.
+ *
+ * We can get ahead of this by installing our own thread-local WH_GETMESSAGE
+ * hook. Since thread-local hooks are called ahead of global hooks, we will
+ * see these registered messages before tiptsf does. At this point we can then
+ * raise a flag that blocks a11y before invoking CallNextHookEx which will then
+ * invoke the global tiptsf hook. Then when we see WM_GETOBJECT, we check the
+ * flag by calling TIPMessageHandler::IsA11yBlocked().
+ *
+ * For Windows 8, we also hook tiptsf!ProcessCaretEvents, which is an a11y hook
+ * function that also calls into UIA.
+ */
+class TIPMessageHandler {
+ public:
+  ~TIPMessageHandler() {
+    if (mHook) {
+      ::UnhookWindowsHookEx(mHook);
+    }
+  }
+
+  static void Initialize() {
+    if (sInstance) {
+      return;
+    }
+
+    sInstance = new TIPMessageHandler();
+    ClearOnShutdown(&sInstance);
+  }
+
+  static bool IsA11yBlocked() {
+    if (!sInstance) {
+      return false;
+    }
+
+    return sInstance->mA11yBlockCount > 0;
+  }
+
+ private:
+  TIPMessageHandler() : mHook(nullptr), mA11yBlockCount(0) {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    // Registered messages used by tiptsf
+    mMessages[0] = ::RegisterWindowMessage(L"ImmersiveFocusNotification");
+    mMessages[1] = ::RegisterWindowMessage(L"TipCloseMenus");
+    mMessages[2] = ::RegisterWindowMessage(L"TabletInputPanelOpening");
+    mMessages[3] = ::RegisterWindowMessage(L"IHM Pen or Touch Event noticed");
+    mMessages[4] = ::RegisterWindowMessage(L"ProgrammabilityCaretVisibility");
+    mMessages[5] = ::RegisterWindowMessage(L"CaretTrackingUpdateIPHidden");
+    mMessages[6] = ::RegisterWindowMessage(L"CaretTrackingUpdateIPInfo");
+
+    mHook = ::SetWindowsHookEx(WH_GETMESSAGE, &TIPHook, nullptr,
+                               ::GetCurrentThreadId());
+    MOZ_ASSERT(mHook);
+
+    if (!sSendMessageTimeoutWStub) {
+      sUser32Intercept.Init("user32.dll");
+      DebugOnly<bool> hooked = sSendMessageTimeoutWStub.Set(
+          sUser32Intercept, "SendMessageTimeoutW", &SendMessageTimeoutWHook);
+      MOZ_ASSERT(hooked);
+    }
+  }
+
+  class MOZ_RAII A11yInstantiationBlocker {
+   public:
+    A11yInstantiationBlocker() {
+      if (!TIPMessageHandler::sInstance) {
+        return;
+      }
+      ++TIPMessageHandler::sInstance->mA11yBlockCount;
+    }
+
+    ~A11yInstantiationBlocker() {
+      if (!TIPMessageHandler::sInstance) {
+        return;
+      }
+      MOZ_ASSERT(TIPMessageHandler::sInstance->mA11yBlockCount > 0);
+      --TIPMessageHandler::sInstance->mA11yBlockCount;
+    }
+  };
+
+  friend class A11yInstantiationBlocker;
+
+  static LRESULT CALLBACK TIPHook(int aCode, WPARAM aWParam, LPARAM aLParam) {
+    if (aCode < 0 || !sInstance) {
+      return ::CallNextHookEx(nullptr, aCode, aWParam, aLParam);
+    }
+
+    MSG* msg = reinterpret_cast<MSG*>(aLParam);
+    UINT& msgCode = msg->message;
+
+    for (uint32_t i = 0; i < ArrayLength(sInstance->mMessages); ++i) {
+      if (msgCode == sInstance->mMessages[i]) {
+        A11yInstantiationBlocker block;
+        return ::CallNextHookEx(nullptr, aCode, aWParam, aLParam);
+      }
+    }
+
+    return ::CallNextHookEx(nullptr, aCode, aWParam, aLParam);
+  }
+
+  static LRESULT WINAPI SendMessageTimeoutWHook(HWND aHwnd, UINT aMsgCode,
+                                                WPARAM aWParam, LPARAM aLParam,
+                                                UINT aFlags, UINT aTimeout,
+                                                PDWORD_PTR aMsgResult) {
+    // We don't want to handle this unless the message is a WM_GETOBJECT that we
+    // want to block, and the aHwnd is a nsWindow that belongs to the current
+    // (i.e., main) thread.
+    if (!aMsgResult || aMsgCode != WM_GETOBJECT ||
+        static_cast<LONG>(aLParam) != OBJID_CLIENT || !::NS_IsMainThread() ||
+        !WinUtils::GetNSWindowPtr(aHwnd) || !IsA11yBlocked()) {
+      return sSendMessageTimeoutWStub(aHwnd, aMsgCode, aWParam, aLParam, aFlags,
+                                      aTimeout, aMsgResult);
+    }
+
+    // In this case we want to fake the result that would happen if we had
+    // decided not to handle WM_GETOBJECT in our WndProc. We hand the message
+    // off to DefWindowProc to accomplish this.
+    *aMsgResult = static_cast<DWORD_PTR>(
+        ::DefWindowProcW(aHwnd, aMsgCode, aWParam, aLParam));
+
+    return static_cast<LRESULT>(TRUE);
+  }
+
+  static WindowsDllInterceptor::FuncHookType<decltype(&SendMessageTimeoutW)>
+      sSendMessageTimeoutWStub;
+  static StaticAutoPtr<TIPMessageHandler> sInstance;
+
+  HHOOK mHook;
+  UINT mMessages[7];
+  uint32_t mA11yBlockCount;
+};
+
+WindowsDllInterceptor::FuncHookType<decltype(&SendMessageTimeoutW)>
+    TIPMessageHandler::sSendMessageTimeoutWStub;
+StaticAutoPtr<TIPMessageHandler> TIPMessageHandler::sInstance;
+
+}  // namespace mozilla
+
+#endif  // defined(ACCESSIBILITY)
+
+namespace mozilla {
+
+// This task will get the VirtualDesktopManager from the generic thread pool
+// since doing this on the main thread on startup causes performance issues.
+//
+// See bug 1640852.
+//
+// This should be fine and should not require any locking, as when the main
+// thread will access it, if it races with this function it will either find
+// it to be null or to have a valid value.
+class InitializeVirtualDesktopManagerTask : public Task {
+ public:
+  InitializeVirtualDesktopManagerTask()
+      : Task(Kind::OffMainThreadOnly, kDefaultPriorityValue) {}
+
+#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
+  bool GetName(nsACString& aName) override {
+    aName.AssignLiteral("InitializeVirtualDesktopManagerTask");
+    return true;
+  }
+#endif
+
+  virtual TaskResult Run() override {
+    RefPtr<IVirtualDesktopManager> desktopManager;
+    HRESULT hr = ::CoCreateInstance(
+        CLSID_VirtualDesktopManager, NULL, CLSCTX_INPROC_SERVER,
+        __uuidof(IVirtualDesktopManager), getter_AddRefs(desktopManager));
+    if (FAILED(hr)) {
+      return TaskResult::Complete;
+    }
+
+    gVirtualDesktopManager = desktopManager;
+    return TaskResult::Complete;
+  }
+};
+
+// Ground-truth query: does Windows claim the window is cloaked right now?
+static bool IsCloaked(HWND hwnd) {
+  DWORD cloakedState;
+  HRESULT hr = ::DwmGetWindowAttribute(hwnd, DWMWA_CLOAKED, &cloakedState,
+                                       sizeof(cloakedState));
+
+  if (FAILED(hr)) {
+    MOZ_LOG(sCloakingLog, LogLevel::Warning,
+            ("failed (%08lX) to query cloaking state for HWND %p", hr, hwnd));
+    return false;
+  }
+
+  return cloakedState != 0;
+}
+
+}  // namespace mozilla
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: nsIWidget impl.
+ **
+ ** nsIWidget interface implementation, broken down into
+ ** sections.
+ **
+ **************************************************************
+ **************************************************************/
+
+/**************************************************************
+ *
+ * SECTION: nsWindow construction and destruction
+ *
+ **************************************************************/
+
+nsWindow::nsWindow(bool aIsChildWindow)
+    : nsBaseWidget(BorderStyle::Default),
+      mBrush(::CreateSolidBrush(NSRGB_2_COLOREF(::GetSysColor(COLOR_BTNFACE)))),
+      mFrameState(std::in_place, this),
+      mIsChildWindow(aIsChildWindow),
+      mLastPaintEndTime(TimeStamp::Now()),
+      mCachedHitTestTime(TimeStamp::Now()),
+      mSizeConstraintsScale(GetDefaultScale().scale),
+      mDesktopId("DesktopIdMutex") {
+  MOZ_ASSERT(mWindowType == WindowType::Child);
+
+  if (!gInitializedVirtualDesktopManager) {
+    TaskController::Get()->AddTask(
+        MakeAndAddRef<InitializeVirtualDesktopManagerTask>());
+    gInitializedVirtualDesktopManager = true;
+  }
+
+  // Global initialization
+  if (!sInstanceCount) {
+    // Global app registration id for Win7 and up. See
+    // WinTaskbar.cpp for details.
+    // MSIX packages explicitly do not support setting the appid from within
+    // the app, as it is set in the package manifest instead.
+    if (!WinUtils::HasPackageIdentity()) {
+      mozilla::widget::WinTaskbar::RegisterAppUserModelID();
+    }
+    if (!StaticPrefs::ui_key_layout_load_when_first_needed()) {
+      KeyboardLayout::GetInstance()->OnLayoutChange(::GetKeyboardLayout(0));
+    }
+#if defined(ACCESSIBILITY)
+    mozilla::TIPMessageHandler::Initialize();
+#endif  // defined(ACCESSIBILITY)
+    if (SUCCEEDED(::OleInitialize(nullptr))) {
+      sIsOleInitialized = true;
+    }
+    NS_ASSERTION(sIsOleInitialized, "***** OLE is not initialized!\n");
+    MouseScrollHandler::Initialize();
+    // Init theme data
+    nsUXThemeData::UpdateNativeThemeInfo();
+    RedirectedKeyDownMessageManager::Forget();
+  }  // !sInstanceCount
+
+  sInstanceCount++;
+}
+
+nsWindow::~nsWindow() {
+  mInDtor = true;
+
+  // If the widget was released without calling Destroy() then the native window
+  // still exists, and we need to destroy it. Destroy() will early-return if it
+  // was already called. In any case it is important to call it before
+  // destroying mPresentLock (cf. 1156182).
+  Destroy();
+
+  // Free app icon resources.  This must happen after `OnDestroy` (see bug
+  // 708033).
+  if (mIconSmall) ::DestroyIcon(mIconSmall);
+
+  if (mIconBig) ::DestroyIcon(mIconBig);
+
+  sInstanceCount--;
+
+  // Global shutdown
+  if (sInstanceCount == 0) {
+    IMEHandler::Terminate();
+    sCurrentCursor = {};
+    if (sIsOleInitialized) {
+      ::OleFlushClipboard();
+      ::OleUninitialize();
+      sIsOleInitialized = false;
+    }
+  }
+
+  NS_IF_RELEASE(mNativeDragTarget);
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::Create, nsIWidget::Destroy
+ *
+ * Creating and destroying windows for this widget.
+ *
+ **************************************************************/
+
+// Allow Derived classes to modify the height that is passed
+// when the window is created or resized.
+int32_t nsWindow::GetHeight(int32_t aProposedHeight) { return aProposedHeight; }
+
+void nsWindow::SendAnAPZEvent(InputData& aEvent) {
+  LRESULT popupHandlingResult;
+  if (DealWithPopups(mWnd, MOZ_WM_DMANIP, 0, 0, &popupHandlingResult)) {
+    // We need to consume the event after using it to roll up the popup(s).
+    return;
+  }
+
+  if (mSwipeTracker && aEvent.mInputType == PANGESTURE_INPUT) {
+    // Give the swipe tracker a first pass at the event. If a new pan gesture
+    // has been started since the beginning of the swipe, the swipe tracker
+    // will know to ignore the event.
+    nsEventStatus status =
+        mSwipeTracker->ProcessEvent(aEvent.AsPanGestureInput());
+    if (status == nsEventStatus_eConsumeNoDefault) {
+      return;
+    }
+  }
+
+  APZEventResult result;
+  if (mAPZC) {
+    result = mAPZC->InputBridge()->ReceiveInputEvent(aEvent);
+  }
+  if (result.GetStatus() == nsEventStatus_eConsumeNoDefault) {
+    return;
+  }
+
+  MOZ_ASSERT(aEvent.mInputType == PANGESTURE_INPUT ||
+             aEvent.mInputType == PINCHGESTURE_INPUT);
+
+  if (aEvent.mInputType == PANGESTURE_INPUT) {
+    PanGestureInput& panInput = aEvent.AsPanGestureInput();
+    WidgetWheelEvent event = panInput.ToWidgetEvent(this);
+    if (!mAPZC) {
+      if (MayStartSwipeForNonAPZ(panInput)) {
+        return;
+      }
+    } else {
+      event = MayStartSwipeForAPZ(panInput, result);
+    }
+
+    ProcessUntransformedAPZEvent(&event, result);
+
+    return;
+  }
+
+  PinchGestureInput& pinchInput = aEvent.AsPinchGestureInput();
+  WidgetWheelEvent event = pinchInput.ToWidgetEvent(this);
+  ProcessUntransformedAPZEvent(&event, result);
+}
+
+void nsWindow::RecreateDirectManipulationIfNeeded() {
+  DestroyDirectManipulation();
+
+  if (mWindowType != WindowType::TopLevel && mWindowType != WindowType::Popup) {
+    return;
+  }
+
+  if (!(StaticPrefs::apz_allow_zooming() ||
+        StaticPrefs::apz_windows_use_direct_manipulation()) ||
+      StaticPrefs::apz_windows_force_disable_direct_manipulation()) {
+    return;
+  }
+
+  mDmOwner = MakeUnique<DirectManipulationOwner>(this);
+
+  LayoutDeviceIntRect bounds(mBounds.X(), mBounds.Y(), mBounds.Width(),
+                             GetHeight(mBounds.Height()));
+  mDmOwner->Init(bounds);
+}
+
+void nsWindow::ResizeDirectManipulationViewport() {
+  if (mDmOwner) {
+    LayoutDeviceIntRect bounds(mBounds.X(), mBounds.Y(), mBounds.Width(),
+                               GetHeight(mBounds.Height()));
+    mDmOwner->ResizeViewport(bounds);
+  }
+}
+
+void nsWindow::DestroyDirectManipulation() {
+  if (mDmOwner) {
+    mDmOwner->Destroy();
+    mDmOwner.reset();
+  }
+}
+
+// Create the proper widget
+nsresult nsWindow::Create(nsIWidget* aParent, nsNativeWidget aNativeParent,
+                          const LayoutDeviceIntRect& aRect,
+                          widget::InitData* aInitData) {
+  // Historical note: there was once some belief and/or intent that nsWindows
+  // could be created on arbitrary threads, and this may still be reflected in
+  // some comments.
+  MOZ_ASSERT(NS_IsMainThread());
+
+  widget::InitData defaultInitData;
+  if (!aInitData) aInitData = &defaultInitData;
+
+  nsIWidget* baseParent =
+      aInitData->mWindowType == WindowType::Dialog ||
+              aInitData->mWindowType == WindowType::TopLevel ||
+              aInitData->mWindowType == WindowType::Invisible
+          ? nullptr
+          : aParent;
+
+  mIsTopWidgetWindow = (nullptr == baseParent);
+  mBounds = aRect;
+
+  // Ensure that the toolkit is created.
+  nsToolkit::GetToolkit();
+
+  BaseCreate(baseParent, aInitData);
+
+  HWND parent;
+  if (aParent) {  // has a nsIWidget parent
+    parent = aParent ? (HWND)aParent->GetNativeData(NS_NATIVE_WINDOW) : nullptr;
+    mParent = aParent;
+  } else {  // has a nsNative parent
+    parent = (HWND)aNativeParent;
+    mParent =
+        aNativeParent ? WinUtils::GetNSWindowPtr((HWND)aNativeParent) : nullptr;
+  }
+
+  mIsRTL = aInitData->mRTL;
+  mOpeningAnimationSuppressed = aInitData->mIsAnimationSuppressed;
+  mAlwaysOnTop = aInitData->mAlwaysOnTop;
+  mIsAlert = aInitData->mIsAlert;
+  mResizable = aInitData->mResizable;
+
+  DWORD style = WindowStyle();
+  DWORD extendedStyle = WindowExStyle();
+
+  if (mWindowType == WindowType::Popup) {
+    if (!aParent) {
+      parent = nullptr;
+    }
+  } else if (mWindowType == WindowType::Invisible) {
+    // Make sure CreateWindowEx succeeds at creating a toplevel window
+    style &= ~0x40000000;  // WS_CHILDWINDOW
+  } else {
+    // See if the caller wants to explictly set clip children and clip siblings
+    if (aInitData->mClipChildren) {
+      style |= WS_CLIPCHILDREN;
+    } else {
+      style &= ~WS_CLIPCHILDREN;
+    }
+    if (aInitData->mClipSiblings) {
+      style |= WS_CLIPSIBLINGS;
+    }
+  }
+
+  const wchar_t* className = ChooseWindowClass(mWindowType);
+
+  // Take specific actions when creating the first top-level window
+  static bool sFirstTopLevelWindowCreated = false;
+  if (aInitData->mWindowType == WindowType::TopLevel && !aParent &&
+      !sFirstTopLevelWindowCreated) {
+    sFirstTopLevelWindowCreated = true;
+    mWnd = ConsumePreXULSkeletonUIHandle();
+    auto skeletonUIError = GetPreXULSkeletonUIErrorReason();
+    if (skeletonUIError) {
+      nsAutoString errorString(
+          GetPreXULSkeletonUIErrorString(skeletonUIError.value()));
+      Telemetry::ScalarSet(
+          Telemetry::ScalarID::STARTUP_SKELETON_UI_DISABLED_REASON,
+          errorString);
+    }
+    if (mWnd) {
+      MOZ_ASSERT(style == kPreXULSkeletonUIWindowStyle,
+                 "The skeleton UI window style should match the expected "
+                 "style for the first window created");
+      MOZ_ASSERT(extendedStyle == kPreXULSkeletonUIWindowStyleEx,
+                 "The skeleton UI window extended style should match the "
+                 "expected extended style for the first window created");
+      MOZ_ASSERT(
+          ::GetWindowThreadProcessId(mWnd, nullptr) == ::GetCurrentThreadId(),
+          "The skeleton UI window should be created on the same thread as "
+          "other windows");
+      mIsShowingPreXULSkeletonUI = true;
+
+      // If we successfully consumed the pre-XUL skeleton UI, just update
+      // our internal state to match what is currently being displayed.
+      mIsVisible = true;
+      mIsCloaked = mozilla::IsCloaked(mWnd);
+      mFrameState->ConsumePreXULSkeletonState(WasPreXULSkeletonUIMaximized());
+
+      // These match the margins set in browser-tabsintitlebar.js with
+      // default prefs on Windows. Bug 1673092 tracks lining this up with
+      // that more correctly instead of hard-coding it.
+      SetNonClientMargins(LayoutDeviceIntMargin(0, 2, 2, 2));
+
+      // Reset the WNDPROC for this window and its whole class, as we had
+      // to use our own WNDPROC when creating the the skeleton UI window.
+      ::SetWindowLongPtrW(mWnd, GWLP_WNDPROC,
+                          reinterpret_cast<LONG_PTR>(
+                              WinUtils::NonClientDpiScalingDefWindowProcW));
+      ::SetClassLongPtrW(mWnd, GCLP_WNDPROC,
+                         reinterpret_cast<LONG_PTR>(
+                             WinUtils::NonClientDpiScalingDefWindowProcW));
+    }
+  }
+
+  if (!mWnd) {
+    mWnd =
+        ::CreateWindowExW(extendedStyle, className, L"", style, aRect.X(),
+                          aRect.Y(), aRect.Width(), GetHeight(aRect.Height()),
+                          parent, nullptr, nsToolkit::mDllInstance, nullptr);
+  }
+
+  if (!mWnd) {
+    NS_WARNING("nsWindow CreateWindowEx failed.");
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!sWinCloakEventHook) {
+    MOZ_LOG(sCloakingLog, LogLevel::Info, ("Registering cloaking event hook"));
+
+    // C++03 lambda approximation until P2173R1 is available (-std=c++2b)
+    struct StdcallLambda {
+      static void CALLBACK OnCloakUncloakHook(HWINEVENTHOOK hWinEventHook,
+                                              DWORD event, HWND hwnd,
+                                              LONG idObject, LONG idChild,
+                                              DWORD idEventThread,
+                                              DWORD dwmsEventTime) {
+        const bool isCloaked = event == EVENT_OBJECT_CLOAKED ? true : false;
+        nsWindow::OnCloakEvent(hwnd, isCloaked);
+      }
+    };
+
+    const HWINEVENTHOOK hook = ::SetWinEventHook(
+        EVENT_OBJECT_CLOAKED, EVENT_OBJECT_UNCLOAKED, HMODULE(nullptr),
+        &StdcallLambda::OnCloakUncloakHook, ::GetCurrentProcessId(),
+        ::GetCurrentThreadId(), WINEVENT_OUTOFCONTEXT);
+    sWinCloakEventHook = Some(hook);
+
+    if (!hook) {
+      const DWORD err = ::GetLastError();
+      MOZ_LOG(sCloakingLog, LogLevel::Error,
+              ("Failed to register cloaking event hook! GLE = %lu (0x%lX)", err,
+               err));
+    }
+  }
+
+  if (aInitData->mIsPrivate) {
+    if (NimbusFeatures::GetBool("majorRelease2022"_ns,
+                                "feltPrivacyWindowSeparation"_ns, true) &&
+        // Although permanent Private Browsing mode is indeed Private Browsing,
+        // we choose to make it look like regular Firefox in terms of the icon
+        // it uses (which also means we shouldn't use the Private Browsing
+        // AUMID).
+        !StaticPrefs::browser_privatebrowsing_autostart()) {
+      RefPtr<IPropertyStore> pPropStore;
+      if (!FAILED(SHGetPropertyStoreForWindow(mWnd, IID_IPropertyStore,
+                                              getter_AddRefs(pPropStore)))) {
+        PROPVARIANT pv;
+        nsAutoString aumid;
+        // make sure we're using the private browsing AUMID so that taskbar
+        // grouping works properly
+        Unused << NS_WARN_IF(
+            !mozilla::widget::WinTaskbar::GenerateAppUserModelID(aumid, true));
+        if (!FAILED(InitPropVariantFromString(aumid.get(), &pv))) {
+          if (!FAILED(pPropStore->SetValue(PKEY_AppUserModel_ID, pv))) {
+            pPropStore->Commit();
+          }
+
+          PropVariantClear(&pv);
+        }
+      }
+      HICON icon = ::LoadIconW(::GetModuleHandleW(nullptr),
+                               MAKEINTRESOURCEW(IDI_PBMODE));
+      SetBigIcon(icon);
+      SetSmallIcon(icon);
+    }
+  }
+
+  mDeviceNotifyHandle = InputDeviceUtils::RegisterNotification(mWnd);
+
+  // If mDefaultScale is set before mWnd has been set, it will have the scale of
+  // the primary monitor, rather than the monitor that the window is actually
+  // on. For non-popup windows this gets corrected by the WM_DPICHANGED message
+  // which resets mDefaultScale, but for popup windows we don't reset
+  // mDefaultScale on that message. In order to ensure that popup windows
+  // spawned on a non-primary monitor end up with the correct scale, we reset
+  // mDefaultScale here so that it gets recomputed using the correct monitor now
+  // that we have a mWnd.
+  mDefaultScale = -1.0;
+
+  if (mIsRTL) {
+    DWORD dwAttribute = TRUE;
+    DwmSetWindowAttribute(mWnd, DWMWA_NONCLIENT_RTL_LAYOUT, &dwAttribute,
+                          sizeof dwAttribute);
+  }
+
+  UpdateDarkModeToolbar();
+
+  if (mOpeningAnimationSuppressed) {
+    SuppressAnimation(true);
+  }
+
+  if (mAlwaysOnTop) {
+    ::SetWindowPos(mWnd, HWND_TOPMOST, 0, 0, 0, 0,
+                   SWP_NOMOVE | SWP_NOSIZE | SWP_NOACTIVATE);
+  }
+
+  if (mWindowType != WindowType::Invisible &&
+      MouseScrollHandler::Device::IsFakeScrollableWindowNeeded()) {
+    // Ugly Thinkpad Driver Hack (Bugs 507222 and 594977)
+    //
+    // We create two zero-sized windows as descendants of the top-level window,
+    // like so:
+    //
+    //   Top-level window (MozillaWindowClass)
+    //     FAKETRACKPOINTSCROLLCONTAINER (MozillaWindowClass)
+    //       FAKETRACKPOINTSCROLLABLE (MozillaWindowClass)
+    //
+    // We need to have the middle window, otherwise the Trackpoint driver
+    // will fail to deliver scroll messages.  WM_MOUSEWHEEL messages are
+    // sent to the FAKETRACKPOINTSCROLLABLE, which then propagate up the
+    // window hierarchy until they are handled by nsWindow::WindowProc.
+    // WM_HSCROLL messages are also sent to the FAKETRACKPOINTSCROLLABLE,
+    // but these do not propagate automatically, so we have the window
+    // procedure pretend that they were dispatched to the top-level window
+    // instead.
+    //
+    // The FAKETRACKPOINTSCROLLABLE needs to have the specific window styles it
+    // is given below so that it catches the Trackpoint driver's heuristics.
+    HWND scrollContainerWnd = ::CreateWindowW(
+        className, L"FAKETRACKPOINTSCROLLCONTAINER", WS_CHILD | WS_VISIBLE, 0,
+        0, 0, 0, mWnd, nullptr, nsToolkit::mDllInstance, nullptr);
+    HWND scrollableWnd = ::CreateWindowW(
+        className, L"FAKETRACKPOINTSCROLLABLE",
+        WS_CHILD | WS_VISIBLE | WS_VSCROLL | WS_TABSTOP | 0x30, 0, 0, 0, 0,
+        scrollContainerWnd, nullptr, nsToolkit::mDllInstance, nullptr);
+
+    // Give the FAKETRACKPOINTSCROLLABLE window a specific ID so that
+    // WindowProcInternal can distinguish it from the top-level window
+    // easily.
+    ::SetWindowLongPtrW(scrollableWnd, GWLP_ID, eFakeTrackPointScrollableID);
+
+    // Make FAKETRACKPOINTSCROLLABLE use nsWindow::WindowProc, and store the
+    // old window procedure in its "user data".
+    WNDPROC oldWndProc = (WNDPROC)::SetWindowLongPtrW(
+        scrollableWnd, GWLP_WNDPROC, (LONG_PTR)nsWindow::WindowProc);
+    ::SetWindowLongPtrW(scrollableWnd, GWLP_USERDATA, (LONG_PTR)oldWndProc);
+  }
+
+  // We will start receiving native events after associating with our native
+  // window. We will also become the output of WinUtils::GetNSWindowPtr for that
+  // window.
+  if (!AssociateWithNativeWindow()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Starting with Windows XP, a process always runs within a terminal services
+  // session. In order to play nicely with RDP, fast user switching, and the
+  // lock screen, we should be handling WM_WTSSESSION_CHANGE. We must register
+  // our HWND in order to receive this message.
+  DebugOnly<BOOL> wtsRegistered =
+      ::WTSRegisterSessionNotification(mWnd, NOTIFY_FOR_THIS_SESSION);
+  NS_ASSERTION(wtsRegistered, "WTSRegisterSessionNotification failed!\n");
+
+  mDefaultIMC.Init(this);
+  IMEHandler::InitInputContext(this, mInputContext);
+
+  static bool a11yPrimed = false;
+  if (!a11yPrimed && mWindowType == WindowType::TopLevel) {
+    a11yPrimed = true;
+    if (Preferences::GetInt("accessibility.force_disabled", 0) == -1) {
+      ::PostMessage(mWnd, MOZ_WM_STARTA11Y, 0, 0);
+    }
+  }
+
+  RecreateDirectManipulationIfNeeded();
+
+  return NS_OK;
+}
+
+void nsWindow::LocalesChanged() {
+  bool isRTL = intl::LocaleService::GetInstance()->IsAppLocaleRTL();
+  if (mIsRTL != isRTL) {
+    DWORD dwAttribute = isRTL;
+    DwmSetWindowAttribute(mWnd, DWMWA_NONCLIENT_RTL_LAYOUT, &dwAttribute,
+                          sizeof dwAttribute);
+    mIsRTL = isRTL;
+  }
+}
+
+// Close this nsWindow
+void nsWindow::Destroy() {
+  // WM_DESTROY has already fired, avoid calling it twice
+  if (mOnDestroyCalled) return;
+
+  // Don't destroy windows that have file pickers open, we'll tear these down
+  // later once the picker is closed.
+  mDestroyCalled = true;
+  if (mPickerDisplayCount) return;
+
+  // During the destruction of all of our children, make sure we don't get
+  // deleted.
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
+
+  DestroyDirectManipulation();
+
+  /**
+   * On windows the LayerManagerOGL destructor wants the widget to be around for
+   * cleanup. It also would like to have the HWND intact, so we nullptr it here.
+   */
+  DestroyLayerManager();
+
+  InputDeviceUtils::UnregisterNotification(mDeviceNotifyHandle);
+  mDeviceNotifyHandle = nullptr;
+
+  // The DestroyWindow function destroys the specified window. The function
+  // sends WM_DESTROY and WM_NCDESTROY messages to the window to deactivate it
+  // and remove the keyboard focus from it. The function also destroys the
+  // window's menu, flushes the thread message queue, destroys timers, removes
+  // clipboard ownership, and breaks the clipboard viewer chain (if the window
+  // is at the top of the viewer chain).
+  //
+  // If the specified window is a parent or owner window, DestroyWindow
+  // automatically destroys the associated child or owned windows when it
+  // destroys the parent or owner window. The function first destroys child or
+  // owned windows, and then it destroys the parent or owner window.
+  VERIFY(::DestroyWindow(mWnd));
+
+  // Our windows can be subclassed which may prevent us receiving WM_DESTROY. If
+  // OnDestroy() didn't get called, call it now.
+  if (false == mOnDestroyCalled) {
+    MSGResult msgResult;
+    mWindowHook.Notify(mWnd, WM_DESTROY, 0, 0, msgResult);
+    OnDestroy();
+  }
+}
+
+/**************************************************************
+ *
+ * SECTION: Window class utilities
+ *
+ * Utilities for calculating the proper window class name for
+ * Create window.
+ *
+ **************************************************************/
+
+/* static */
+const wchar_t* nsWindow::RegisterWindowClass(const wchar_t* aClassName,
+                                             UINT aExtraStyle, LPWSTR aIconID) {
+  WNDCLASSW wc;
+  if (::GetClassInfoW(nsToolkit::mDllInstance, aClassName, &wc)) {
+    // already registered
+    return aClassName;
+  }
+
+  wc.style = CS_DBLCLKS | aExtraStyle;
+  wc.lpfnWndProc = WinUtils::NonClientDpiScalingDefWindowProcW;
+  wc.cbClsExtra = 0;
+  wc.cbWndExtra = 0;
+  wc.hInstance = nsToolkit::mDllInstance;
+  wc.hIcon =
+      aIconID ? ::LoadIconW(::GetModuleHandleW(nullptr), aIconID) : nullptr;
+  wc.hCursor = nullptr;
+  wc.hbrBackground = nullptr;
+  wc.lpszMenuName = nullptr;
+  wc.lpszClassName = aClassName;
+
+  if (!::RegisterClassW(&wc)) {
+    // For older versions of Win32 (i.e., not XP), the registration may
+    // fail with aExtraStyle, so we have to re-register without it.
+    wc.style = CS_DBLCLKS;
+    ::RegisterClassW(&wc);
+  }
+  return aClassName;
+}
+
+static LPWSTR const gStockApplicationIcon = MAKEINTRESOURCEW(32512);
+
+/* static */
+const wchar_t* nsWindow::ChooseWindowClass(WindowType aWindowType) {
+  switch (aWindowType) {
+    case WindowType::Invisible:
+      return RegisterWindowClass(kClassNameHidden, 0, gStockApplicationIcon);
+    case WindowType::Dialog:
+      return RegisterWindowClass(kClassNameDialog, 0, nullptr);
+    case WindowType::Popup:
+      return RegisterWindowClass(kClassNameDropShadow, 0,
+                                 gStockApplicationIcon);
+    default:
+      return RegisterWindowClass(GetMainWindowClass(), 0,
+                                 gStockApplicationIcon);
+  }
+}
+
+/**************************************************************
+ *
+ * SECTION: Window styles utilities
+ *
+ * Return the proper windows styles and extended styles.
+ *
+ **************************************************************/
+
+// Return nsWindow styles
+DWORD nsWindow::WindowStyle() {
+  DWORD style;
+
+  switch (mWindowType) {
+    case WindowType::Child:
+      style = WS_OVERLAPPED;
+      break;
+
+    case WindowType::Dialog:
+      style = WS_OVERLAPPED | WS_BORDER | WS_DLGFRAME | WS_SYSMENU | DS_3DLOOK |
+              DS_MODALFRAME | WS_CLIPCHILDREN;
+      if (mBorderStyle != BorderStyle::Default)
+        style |= WS_THICKFRAME | WS_MINIMIZEBOX | WS_MAXIMIZEBOX;
+      break;
+
+    case WindowType::Popup:
+      style = WS_POPUP | WS_OVERLAPPED;
+      break;
+
+    default:
+      NS_ERROR("unknown border style");
+      [[fallthrough]];
+
+    case WindowType::TopLevel:
+    case WindowType::Invisible:
+      style = WS_OVERLAPPED | WS_BORDER | WS_DLGFRAME | WS_SYSMENU |
+              WS_THICKFRAME | WS_MINIMIZEBOX | WS_MAXIMIZEBOX | WS_CLIPCHILDREN;
+      break;
+  }
+
+  if (mBorderStyle != BorderStyle::Default &&
+      mBorderStyle != BorderStyle::All) {
+    if (mBorderStyle == BorderStyle::None ||
+        !(mBorderStyle & BorderStyle::Border))
+      style &= ~WS_BORDER;
+
+    if (mBorderStyle == BorderStyle::None ||
+        !(mBorderStyle & BorderStyle::Title)) {
+      style &= ~WS_DLGFRAME;
+    }
+
+    if (mBorderStyle == BorderStyle::None ||
+        !(mBorderStyle & BorderStyle::Close))
+      style &= ~0;
+    // XXX The close box can only be removed by changing the window class,
+    // as far as I know   --- roc+moz@cs.cmu.edu
+
+    if (mBorderStyle == BorderStyle::None ||
+        !(mBorderStyle & (BorderStyle::Menu | BorderStyle::Close)))
+      style &= ~WS_SYSMENU;
+    // Looks like getting rid of the system menu also does away with the
+    // close box. So, we only get rid of the system menu if you want neither it
+    // nor the close box. How does the Windows "Dialog" window class get just
+    // closebox and no sysmenu? Who knows.
+
+    if (mBorderStyle == BorderStyle::None ||
+        !(mBorderStyle & BorderStyle::ResizeH))
+      style &= ~WS_THICKFRAME;
+
+    if (mBorderStyle == BorderStyle::None ||
+        !(mBorderStyle & BorderStyle::Minimize))
+      style &= ~WS_MINIMIZEBOX;
+
+    if (mBorderStyle == BorderStyle::None ||
+        !(mBorderStyle & BorderStyle::Maximize))
+      style &= ~WS_MAXIMIZEBOX;
+
+    if (IsPopupWithTitleBar()) {
+      style |= WS_CAPTION;
+      if (mBorderStyle & BorderStyle::Close) {
+        style |= WS_SYSMENU;
+      }
+    }
+  }
+
+  if (mIsChildWindow) {
+    style |= WS_CLIPCHILDREN;
+    if (!(style & WS_POPUP)) {
+      style |= WS_CHILD;  // WS_POPUP and WS_CHILD are mutually exclusive.
+    }
+  }
+
+  VERIFY_WINDOW_STYLE(style);
+  return style;
+}
+
+// Return nsWindow extended styles
+DWORD nsWindow::WindowExStyle() {
+  MOZ_ASSERT_IF(mIsAlert, mWindowType == WindowType::Dialog);
+  switch (mWindowType) {
+    case WindowType::Child:
+      return 0;
+    case WindowType::Popup: {
+      DWORD extendedStyle = WS_EX_TOOLWINDOW;
+      if (mPopupLevel == PopupLevel::Top) {
+        extendedStyle |= WS_EX_TOPMOST;
+      }
+      return extendedStyle;
+    }
+    case WindowType::Dialog: {
+      if (mIsAlert) {
+        return WS_EX_TOOLWINDOW | WS_EX_TOPMOST;
+      }
+      return WS_EX_WINDOWEDGE | WS_EX_DLGMODALFRAME;
+    }
+    case WindowType::Sheet:
+      MOZ_FALLTHROUGH_ASSERT("Sheets are macOS specific");
+    case WindowType::TopLevel:
+    case WindowType::Invisible:
+      break;
+  }
+  return WS_EX_WINDOWEDGE;
+}
+
+/**************************************************************
+ *
+ * SECTION: Native window association utilities
+ *
+ * Used in Create and Destroy. A nsWindow can associate with its
+ * underlying native window mWnd. Once a native window is
+ * associated with a nsWindow, its native events will be handled
+ * by the static member function nsWindow::WindowProc. Moreover,
+ * the association will be registered in the WinUtils association
+ * list, that is, calling WinUtils::GetNSWindowPtr on the native
+ * window will return the associated nsWindow. This is used in
+ * nsWindow::WindowProc to correctly dispatch native events to
+ * the handler methods defined in nsWindow, even though it is a
+ * static member function.
+ *
+ * After dissociation, the native events of the native window will
+ * no longer be handled by nsWindow::WindowProc, and will thus not
+ * be dispatched to the nsWindow native event handler methods.
+ * Moreover, the association will no longer be registered in the
+ * WinUtils association list, so calling WinUtils::GetNSWindowPtr
+ * on the native window will return nullptr.
+ *
+ **************************************************************/
+
+bool nsWindow::AssociateWithNativeWindow() {
+  if (!mWnd || !IsWindow(mWnd)) {
+    NS_ERROR("Invalid window handle");
+    return false;
+  }
+
+  // Connect the this pointer to the native window handle.
+  // This should be done before SetWindowLongPtrW, because nsWindow::WindowProc
+  // uses WinUtils::GetNSWindowPtr internally.
+  WinUtils::SetNSWindowPtr(mWnd, this);
+
+  ::SetLastError(ERROR_SUCCESS);
+  const auto prevWndProc = reinterpret_cast<WNDPROC>(::SetWindowLongPtrW(
+      mWnd, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(nsWindow::WindowProc)));
+  if (!prevWndProc && GetLastError() != ERROR_SUCCESS) {
+    NS_ERROR("Failure in SetWindowLongPtrW");
+    WinUtils::SetNSWindowPtr(mWnd, nullptr);
+    return false;
+  }
+
+  mPrevWndProc.emplace(prevWndProc);
+  return true;
+}
+
+void nsWindow::DissociateFromNativeWindow() {
+  if (!mWnd || !IsWindow(mWnd) || mPrevWndProc.isNothing()) {
+    return;
+  }
+
+  DebugOnly<WNDPROC> wndProcBeforeDissociate =
+      reinterpret_cast<WNDPROC>(::SetWindowLongPtrW(
+          mWnd, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(*mPrevWndProc)));
+  NS_ASSERTION(wndProcBeforeDissociate == nsWindow::WindowProc,
+               "Unstacked an unexpected native window procedure");
+
+  WinUtils::SetNSWindowPtr(mWnd, nullptr);
+  mPrevWndProc.reset();
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::SetParent, nsIWidget::GetParent
+ *
+ * Set or clear the parent widgets using window properties, and
+ * handles calculating native parent handles.
+ *
+ **************************************************************/
+
+// Get and set parent widgets
+void nsWindow::SetParent(nsIWidget* aNewParent) {
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
+  nsIWidget* parent = GetParent();
+  if (parent) {
+    parent->RemoveChild(this);
+  }
+
+  mParent = aNewParent;
+
+  if (aNewParent) {
+    ReparentNativeWidget(aNewParent);
+    aNewParent->AddChild(this);
+    return;
+  }
+  if (mWnd) {
+    // If we have no parent, SetParent should return the desktop.
+    VERIFY(::SetParent(mWnd, nullptr));
+    RecreateDirectManipulationIfNeeded();
+  }
+}
+
+void nsWindow::ReparentNativeWidget(nsIWidget* aNewParent) {
+  MOZ_ASSERT(aNewParent, "null widget");
+
+  mParent = aNewParent;
+  if (mWindowType == WindowType::Popup) {
+    return;
+  }
+  HWND newParent = (HWND)aNewParent->GetNativeData(NS_NATIVE_WINDOW);
+  NS_ASSERTION(newParent, "Parent widget has a null native window handle");
+  if (newParent && mWnd) {
+    ::SetParent(mWnd, newParent);
+    RecreateDirectManipulationIfNeeded();
+  }
+}
+
+nsIWidget* nsWindow::GetParent(void) {
+  if (mIsTopWidgetWindow) {
+    return nullptr;
+  }
+  if (mInDtor || mOnDestroyCalled) {
+    return nullptr;
+  }
+  return mParent;
+}
+
+static int32_t RoundDown(double aDouble) {
+  return aDouble > 0 ? static_cast<int32_t>(floor(aDouble))
+                     : static_cast<int32_t>(ceil(aDouble));
+}
+
+float nsWindow::GetDPI() {
+  float dpi = 96.0f;
+  nsCOMPtr<nsIScreen> screen = GetWidgetScreen();
+  if (screen) {
+    screen->GetDpi(&dpi);
+  }
+  return dpi;
+}
+
+double nsWindow::GetDefaultScaleInternal() {
+  if (mDefaultScale <= 0.0) {
+    mDefaultScale = WinUtils::LogToPhysFactor(mWnd);
+  }
+  return mDefaultScale;
+}
+
+int32_t nsWindow::LogToPhys(double aValue) {
+  return WinUtils::LogToPhys(
+      ::MonitorFromWindow(mWnd, MONITOR_DEFAULTTOPRIMARY), aValue);
+}
+
+nsWindow* nsWindow::GetParentWindow(bool aIncludeOwner) {
+  return static_cast<nsWindow*>(GetParentWindowBase(aIncludeOwner));
+}
+
+nsWindow* nsWindow::GetParentWindowBase(bool aIncludeOwner) {
+  if (mIsTopWidgetWindow) {
+    // Must use a flag instead of mWindowType to tell if the window is the
+    // owned by the topmost widget, because a child window can be embedded
+    // inside a HWND which is not associated with a nsIWidget.
+    return nullptr;
+  }
+
+  // If this widget has already been destroyed, pretend we have no parent.
+  // This corresponds to code in Destroy which removes the destroyed
+  // widget from its parent's child list.
+  if (mInDtor || mOnDestroyCalled) return nullptr;
+
+  // aIncludeOwner set to true implies walking the parent chain to retrieve the
+  // root owner. aIncludeOwner set to false implies the search will stop at the
+  // true parent (default).
+  nsWindow* widget = nullptr;
+  if (mWnd) {
+    HWND parent = nullptr;
+    if (aIncludeOwner)
+      parent = ::GetParent(mWnd);
+    else
+      parent = ::GetAncestor(mWnd, GA_PARENT);
+
+    if (parent) {
+      widget = WinUtils::GetNSWindowPtr(parent);
+      if (widget) {
+        // If the widget is in the process of being destroyed then
+        // do NOT return it
+        if (widget->mInDtor) {
+          widget = nullptr;
+        }
+      }
+    }
+  }
+
+  return widget;
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::Show
+ *
+ * Hide or show this component.
+ *
+ **************************************************************/
+
+void nsWindow::Show(bool bState) {
+  if (bState && mIsShowingPreXULSkeletonUI) {
+    // The first time we decide to actually show the window is when we decide
+    // that we've taken over the window from the skeleton UI, and we should
+    // no longer treat resizes / moves specially.
+    mIsShowingPreXULSkeletonUI = false;
+#if defined(ACCESSIBILITY)
+    // If our HWND has focus and the a11y engine hasn't started yet, fire a
+    // focus win event. Windows already did this when the skeleton UI appeared,
+    // but a11y wouldn't have been able to start at that point even if a client
+    // responded. Firing this now gives clients the chance to respond with
+    // WM_GETOBJECT, which will trigger the a11y engine. We don't want to do
+    // this if the a11y engine has already started because it has probably
+    // already fired focus on a descendant.
+    if (::GetFocus() == mWnd && !GetAccService()) {
+      ::NotifyWinEvent(EVENT_OBJECT_FOCUS, mWnd, OBJID_CLIENT, CHILDID_SELF);
+    }
+#endif  // defined(ACCESSIBILITY)
+  }
+
+  if (mWindowType == WindowType::Popup) {
+    MOZ_ASSERT(ChooseWindowClass(mWindowType) == kClassNameDropShadow);
+    // WS_EX_COMPOSITED conflicts with the WS_EX_LAYERED style and causes
+    // some popup menus to become invisible.
+    LONG_PTR exStyle = ::GetWindowLongPtrW(mWnd, GWL_EXSTYLE);
+    if (exStyle & WS_EX_LAYERED) {
+      ::SetWindowLongPtrW(mWnd, GWL_EXSTYLE, exStyle & ~WS_EX_COMPOSITED);
+    }
+  }
+
+  bool syncInvalidate = false;
+
+  bool wasVisible = mIsVisible;
+  // Set the status now so that anyone asking during ShowWindow or
+  // SetWindowPos would get the correct answer.
+  mIsVisible = bState;
+
+  // We may have cached an out of date visible state. This can happen
+  // when session restore sets the full screen mode.
+  if (mIsVisible)
+    mOldStyle |= WS_VISIBLE;
+  else
+    mOldStyle &= ~WS_VISIBLE;
+
+  if (mWnd) {
+    if (bState) {
+      if (!wasVisible && mWindowType == WindowType::TopLevel) {
+        // speed up the initial paint after show for
+        // top level windows:
+        syncInvalidate = true;
+
+        // Set the cursor before showing the window to avoid the default wait
+        // cursor.
+        SetCursor(Cursor{eCursor_standard});
+
+        switch (mFrameState->GetSizeMode()) {
+          case nsSizeMode_Fullscreen:
+            ::ShowWindow(mWnd, SW_SHOW);
+            break;
+          case nsSizeMode_Maximized:
+            ::ShowWindow(mWnd, SW_SHOWMAXIMIZED);
+            break;
+          case nsSizeMode_Minimized:
+            ::ShowWindow(mWnd, SW_SHOWMINIMIZED);
+            break;
+          default:
+            if (CanTakeFocus() && !mAlwaysOnTop) {
+              ::ShowWindow(mWnd, SW_SHOWNORMAL);
+            } else {
+              ::ShowWindow(mWnd, SW_SHOWNOACTIVATE);
+              // Don't flicker the window if we're restoring session
+              if (!sIsRestoringSession) {
+                Unused << GetAttention(2);
+              }
+            }
+            break;
+        }
+      } else {
+        DWORD flags = SWP_NOSIZE | SWP_NOMOVE | SWP_SHOWWINDOW;
+        if (wasVisible) {
+          flags |= SWP_NOZORDER;
+        }
+        if (mAlwaysOnTop || mIsAlert) {
+          flags |= SWP_NOACTIVATE;
+        }
+
+        if (mWindowType == WindowType::Popup) {
+          // ensure popups are the topmost of the TOPMOST
+          // layer. Remember not to set the SWP_NOZORDER
+          // flag as that might allow the taskbar to overlap
+          // the popup.
+          flags |= SWP_NOACTIVATE;
+          HWND owner = ::GetWindow(mWnd, GW_OWNER);
+          if (owner) {
+            // PopupLevel::Top popups should be above all else.  All other
+            // types should be placed in front of their owner, without
+            // changing the owner's z-level relative to other windows.
+            if (mPopupLevel != PopupLevel::Top) {
+              ::SetWindowPos(mWnd, owner, 0, 0, 0, 0, flags);
+              ::SetWindowPos(owner, mWnd, 0, 0, 0, 0,
+                             SWP_NOMOVE | SWP_NOSIZE | SWP_NOACTIVATE);
+            } else {
+              ::SetWindowPos(mWnd, HWND_TOP, 0, 0, 0, 0, flags);
+            }
+          } else {
+            ::SetWindowPos(mWnd, HWND_TOPMOST, 0, 0, 0, 0, flags);
+          }
+        } else {
+          if (mWindowType == WindowType::Dialog && !CanTakeFocus())
+            flags |= SWP_NOACTIVATE;
+
+          ::SetWindowPos(mWnd, HWND_TOP, 0, 0, 0, 0, flags);
+        }
+      }
+    } else {
+      // Clear contents to avoid ghosting of old content if we display
+      // this window again.
+      if (wasVisible && mTransparencyMode == TransparencyMode::Transparent) {
+        if (mCompositorWidgetDelegate) {
+          mCompositorWidgetDelegate->ClearTransparentWindow();
+        }
+      }
+      if (mWindowType != WindowType::Dialog) {
+        ::ShowWindow(mWnd, SW_HIDE);
+      } else {
+        ::SetWindowPos(mWnd, 0, 0, 0, 0, 0,
+                       SWP_HIDEWINDOW | SWP_NOSIZE | SWP_NOMOVE | SWP_NOZORDER |
+                           SWP_NOACTIVATE);
+      }
+    }
+  }
+
+  if (!wasVisible && bState) {
+    Invalidate();
+    if (syncInvalidate && !mInDtor && !mOnDestroyCalled) {
+      ::UpdateWindow(mWnd);
+    }
+  }
+
+  if (mOpeningAnimationSuppressed) {
+    SuppressAnimation(false);
+  }
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::IsVisible
+ *
+ * Returns the visibility state.
+ *
+ **************************************************************/
+
+// Return true if the component is visible, false otherwise.
+//
+// This does not take cloaking into account.
+bool nsWindow::IsVisible() const { return mIsVisible; }
+
+/**************************************************************
+ *
+ * SECTION: Touch and APZ-related functions
+ *
+ **************************************************************/
+
+void nsWindow::RegisterTouchWindow() {
+  mTouchWindow = true;
+  ::RegisterTouchWindow(mWnd, TWF_WANTPALM);
+  ::EnumChildWindows(mWnd, nsWindow::RegisterTouchForDescendants, 0);
+}
+
+BOOL CALLBACK nsWindow::RegisterTouchForDescendants(HWND aWnd, LPARAM aMsg) {
+  nsWindow* win = WinUtils::GetNSWindowPtr(aWnd);
+  if (win) {
+    ::RegisterTouchWindow(aWnd, TWF_WANTPALM);
+  }
+  return TRUE;
+}
+
+void nsWindow::LockAspectRatio(bool aShouldLock) {
+  if (aShouldLock) {
+    mAspectRatio = (float)mBounds.Width() / (float)mBounds.Height();
+  } else {
+    mAspectRatio = 0.0;
+  }
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::SetInputRegion
+ *
+ * Sets whether the window should ignore mouse events.
+ *
+ **************************************************************/
+void nsWindow::SetInputRegion(const InputRegion& aInputRegion) {
+  mInputRegion = aInputRegion;
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::Move, nsIWidget::Resize, nsIWidget::Size
+ *
+ * Repositioning and sizing a window.
+ *
+ **************************************************************/
+
+void nsWindow::SetSizeConstraints(const SizeConstraints& aConstraints) {
+  SizeConstraints c = aConstraints;
+
+  if (mWindowType != WindowType::Popup && mResizable) {
+    c.mMinSize.width =
+        std::max(int32_t(::GetSystemMetrics(SM_CXMINTRACK)), c.mMinSize.width);
+    c.mMinSize.height =
+        std::max(int32_t(::GetSystemMetrics(SM_CYMINTRACK)), c.mMinSize.height);
+  }
+
+  if (mMaxTextureSize > 0) {
+    // We can't make ThebesLayers bigger than this anyway.. no point it letting
+    // a window grow bigger as we won't be able to draw content there in
+    // general.
+    c.mMaxSize.width = std::min(c.mMaxSize.width, mMaxTextureSize);
+    c.mMaxSize.height = std::min(c.mMaxSize.height, mMaxTextureSize);
+  }
+
+  mSizeConstraintsScale = GetDefaultScale().scale;
+
+  nsBaseWidget::SetSizeConstraints(c);
+}
+
+const SizeConstraints nsWindow::GetSizeConstraints() {
+  double scale = GetDefaultScale().scale;
+  if (mSizeConstraintsScale == scale || mSizeConstraintsScale == 0.0) {
+    return mSizeConstraints;
+  }
+  scale /= mSizeConstraintsScale;
+  SizeConstraints c = mSizeConstraints;
+  if (c.mMinSize.width != NS_MAXSIZE) {
+    c.mMinSize.width = NSToIntRound(c.mMinSize.width * scale);
+  }
+  if (c.mMinSize.height != NS_MAXSIZE) {
+    c.mMinSize.height = NSToIntRound(c.mMinSize.height * scale);
+  }
+  if (c.mMaxSize.width != NS_MAXSIZE) {
+    c.mMaxSize.width = NSToIntRound(c.mMaxSize.width * scale);
+  }
+  if (c.mMaxSize.height != NS_MAXSIZE) {
+    c.mMaxSize.height = NSToIntRound(c.mMaxSize.height * scale);
+  }
+  return c;
+}
+
+// Move this component
+void nsWindow::Move(double aX, double aY) {
+  if (mWindowType == WindowType::TopLevel ||
+      mWindowType == WindowType::Dialog) {
+    SetSizeMode(nsSizeMode_Normal);
+  }
+
+  // for top-level windows only, convert coordinates from desktop pixels
+  // (the "parent" coordinate space) to the window's device pixel space
+  double scale =
+      BoundsUseDesktopPixels() ? GetDesktopToDeviceScale().scale : 1.0;
+  int32_t x = NSToIntRound(aX * scale);
+  int32_t y = NSToIntRound(aY * scale);
+
+  // Check to see if window needs to be moved first
+  // to avoid a costly call to SetWindowPos. This check
+  // can not be moved to the calling code in nsView, because
+  // some platforms do not position child windows correctly
+
+  // Only perform this check for non-popup windows, since the positioning can
+  // in fact change even when the x/y do not.  We always need to perform the
+  // check. See bug #97805 for details.
+  if (mWindowType != WindowType::Popup && mBounds.IsEqualXY(x, y)) {
+    // Nothing to do, since it is already positioned correctly.
+    return;
+  }
+
+  mBounds.MoveTo(x, y);
+
+  if (mWnd) {
+#ifdef DEBUG
+    // complain if a window is moved offscreen (legal, but potentially
+    // worrisome)
+    if (mIsTopWidgetWindow) {  // only a problem for top-level windows
+      // Make sure this window is actually on the screen before we move it
+      // XXX: Needs multiple monitor support
+      HDC dc = ::GetDC(mWnd);
+      if (dc) {
+        if (::GetDeviceCaps(dc, TECHNOLOGY) == DT_RASDISPLAY) {
+          RECT workArea;
+          ::SystemParametersInfo(SPI_GETWORKAREA, 0, &workArea, 0);
+          // no annoying assertions. just mention the issue.
+          if (x < 0 || x >= workArea.right || y < 0 || y >= workArea.bottom) {
+            MOZ_LOG(gWindowsLog, LogLevel::Info,
+                    ("window moved to offscreen position\n"));
+          }
+        }
+        ::ReleaseDC(mWnd, dc);
+      }
+    }
+#endif
+
+    // Normally, when the skeleton UI is disabled, we resize+move the window
+    // before showing it in order to ensure that it restores to the correct
+    // position when the user un-maximizes it. However, when we are using the
+    // skeleton UI, this results in the skeleton UI window being moved around
+    // undesirably before being locked back into the maximized position. To
+    // avoid this, we simply set the placement to restore to via
+    // SetWindowPlacement. It's a little bit more of a dance, though, since we
+    // need to convert the workspace coords that SetWindowPlacement uses to the
+    // screen space coordinates we normally use with SetWindowPos.
+    if (mIsShowingPreXULSkeletonUI && WasPreXULSkeletonUIMaximized()) {
+      WINDOWPLACEMENT pl = {sizeof(WINDOWPLACEMENT)};
+      VERIFY(::GetWindowPlacement(mWnd, &pl));
+
+      HMONITOR monitor = ::MonitorFromWindow(mWnd, MONITOR_DEFAULTTONULL);
+      if (NS_WARN_IF(!monitor)) {
+        return;
+      }
+      MONITORINFO mi = {sizeof(MONITORINFO)};
+      VERIFY(::GetMonitorInfo(monitor, &mi));
+
+      int32_t deltaX =
+          x + mi.rcWork.left - mi.rcMonitor.left - pl.rcNormalPosition.left;
+      int32_t deltaY =
+          y + mi.rcWork.top - mi.rcMonitor.top - pl.rcNormalPosition.top;
+      pl.rcNormalPosition.left += deltaX;
+      pl.rcNormalPosition.right += deltaX;
+      pl.rcNormalPosition.top += deltaY;
+      pl.rcNormalPosition.bottom += deltaY;
+      VERIFY(::SetWindowPlacement(mWnd, &pl));
+    } else {
+      UINT flags = SWP_NOZORDER | SWP_NOACTIVATE | SWP_NOSIZE;
+      double oldScale = mDefaultScale;
+      mResizeState = IN_SIZEMOVE;
+      VERIFY(::SetWindowPos(mWnd, nullptr, x, y, 0, 0, flags));
+      mResizeState = NOT_RESIZING;
+      if (WinUtils::LogToPhysFactor(mWnd) != oldScale) {
+        ChangedDPI();
+      }
+    }
+
+    ResizeDirectManipulationViewport();
+  }
+}
+
+// Resize this component
+void nsWindow::Resize(double aWidth, double aHeight, bool aRepaint) {
+  // for top-level windows only, convert coordinates from desktop pixels
+  // (the "parent" coordinate space) to the window's device pixel space
+  double scale =
+      BoundsUseDesktopPixels() ? GetDesktopToDeviceScale().scale : 1.0;
+  int32_t width = NSToIntRound(aWidth * scale);
+  int32_t height = NSToIntRound(aHeight * scale);
+
+  NS_ASSERTION((width >= 0), "Negative width passed to nsWindow::Resize");
+  NS_ASSERTION((height >= 0), "Negative height passed to nsWindow::Resize");
+  if (width < 0 || height < 0) {
+    gfxCriticalNoteOnce << "Negative passed to Resize(" << width << ", "
+                        << height << ") repaint: " << aRepaint;
+  }
+
+  ConstrainSize(&width, &height);
+
+  // Avoid unnecessary resizing calls
+  if (mBounds.IsEqualSize(width, height)) {
+    if (aRepaint) {
+      Invalidate();
+    }
+    return;
+  }
+
+  // Set cached value for lightweight and printing
+  bool wasLocking = mAspectRatio != 0.0;
+  mBounds.SizeTo(width, height);
+  if (wasLocking) {
+    LockAspectRatio(true);  // This causes us to refresh the mAspectRatio value
+  }
+
+  if (mWnd) {
+    // Refer to the comment above a similar check in nsWindow::Move
+    if (mIsShowingPreXULSkeletonUI && WasPreXULSkeletonUIMaximized()) {
+      WINDOWPLACEMENT pl = {sizeof(WINDOWPLACEMENT)};
+      VERIFY(::GetWindowPlacement(mWnd, &pl));
+      pl.rcNormalPosition.right = pl.rcNormalPosition.left + width;
+      pl.rcNormalPosition.bottom = pl.rcNormalPosition.top + GetHeight(height);
+      mResizeState = RESIZING;
+      VERIFY(::SetWindowPlacement(mWnd, &pl));
+      mResizeState = NOT_RESIZING;
+    } else {
+      UINT flags = SWP_NOZORDER | SWP_NOACTIVATE | SWP_NOMOVE;
+
+      if (!aRepaint) {
+        flags |= SWP_NOREDRAW;
+      }
+
+      double oldScale = mDefaultScale;
+      mResizeState = RESIZING;
+      VERIFY(
+          ::SetWindowPos(mWnd, nullptr, 0, 0, width, GetHeight(height), flags));
+
+      mResizeState = NOT_RESIZING;
+      if (WinUtils::LogToPhysFactor(mWnd) != oldScale) {
+        ChangedDPI();
+      }
+    }
+
+    ResizeDirectManipulationViewport();
+  }
+
+  if (aRepaint) Invalidate();
+}
+
+// Resize this component
+void nsWindow::Resize(double aX, double aY, double aWidth, double aHeight,
+                      bool aRepaint) {
+  // for top-level windows only, convert coordinates from desktop pixels
+  // (the "parent" coordinate space) to the window's device pixel space
+  double scale =
+      BoundsUseDesktopPixels() ? GetDesktopToDeviceScale().scale : 1.0;
+  int32_t x = NSToIntRound(aX * scale);
+  int32_t y = NSToIntRound(aY * scale);
+  int32_t width = NSToIntRound(aWidth * scale);
+  int32_t height = NSToIntRound(aHeight * scale);
+
+  NS_ASSERTION((width >= 0), "Negative width passed to nsWindow::Resize");
+  NS_ASSERTION((height >= 0), "Negative height passed to nsWindow::Resize");
+  if (width < 0 || height < 0) {
+    gfxCriticalNoteOnce << "Negative passed to Resize(" << x << " ," << y
+                        << ", " << width << ", " << height
+                        << ") repaint: " << aRepaint;
+  }
+
+  ConstrainSize(&width, &height);
+
+  // Avoid unnecessary resizing calls
+  if (mBounds.IsEqualRect(x, y, width, height)) {
+    if (aRepaint) {
+      Invalidate();
+    }
+    return;
+  }
+
+  // Set cached value for lightweight and printing
+  mBounds.SetRect(x, y, width, height);
+
+  if (mWnd) {
+    // Refer to the comment above a similar check in nsWindow::Move
+    if (mIsShowingPreXULSkeletonUI && WasPreXULSkeletonUIMaximized()) {
+      WINDOWPLACEMENT pl = {sizeof(WINDOWPLACEMENT)};
+      VERIFY(::GetWindowPlacement(mWnd, &pl));
+
+      HMONITOR monitor = ::MonitorFromWindow(mWnd, MONITOR_DEFAULTTONULL);
+      if (NS_WARN_IF(!monitor)) {
+        return;
+      }
+      MONITORINFO mi = {sizeof(MONITORINFO)};
+      VERIFY(::GetMonitorInfo(monitor, &mi));
+
+      int32_t deltaX =
+          x + mi.rcWork.left - mi.rcMonitor.left - pl.rcNormalPosition.left;
+      int32_t deltaY =
+          y + mi.rcWork.top - mi.rcMonitor.top - pl.rcNormalPosition.top;
+      pl.rcNormalPosition.left += deltaX;
+      pl.rcNormalPosition.right = pl.rcNormalPosition.left + width;
+      pl.rcNormalPosition.top += deltaY;
+      pl.rcNormalPosition.bottom = pl.rcNormalPosition.top + GetHeight(height);
+      VERIFY(::SetWindowPlacement(mWnd, &pl));
+    } else {
+      UINT flags = SWP_NOZORDER | SWP_NOACTIVATE;
+      if (!aRepaint) {
+        flags |= SWP_NOREDRAW;
+      }
+
+      double oldScale = mDefaultScale;
+      mResizeState = RESIZING;
+      VERIFY(
+          ::SetWindowPos(mWnd, nullptr, x, y, width, GetHeight(height), flags));
+      mResizeState = NOT_RESIZING;
+      if (WinUtils::LogToPhysFactor(mWnd) != oldScale) {
+        ChangedDPI();
+      }
+
+      if (mTransitionWnd) {
+        // If we have a fullscreen transition window, we need to make
+        // it topmost again, otherwise the taskbar may be raised by
+        // the system unexpectedly when we leave fullscreen state.
+        ::SetWindowPos(mTransitionWnd, HWND_TOPMOST, 0, 0, 0, 0,
+                       SWP_NOMOVE | SWP_NOSIZE | SWP_NOACTIVATE);
+      }
+    }
+
+    ResizeDirectManipulationViewport();
+  }
+
+  if (aRepaint) Invalidate();
+}
+
+mozilla::Maybe<bool> nsWindow::IsResizingNativeWidget() {
+  if (mResizeState == RESIZING) {
+    return Some(true);
+  }
+  return Some(false);
+}
+
+/**************************************************************
+ *
+ * SECTION: Window Z-order and state.
+ *
+ * nsIWidget::PlaceBehind, nsIWidget::SetSizeMode,
+ * nsIWidget::ConstrainPosition
+ *
+ * Z-order, positioning, restore, minimize, and maximize.
+ *
+ **************************************************************/
+
+// Position the window behind the given window
+void nsWindow::PlaceBehind(nsTopLevelWidgetZPlacement aPlacement,
+                           nsIWidget* aWidget, bool aActivate) {
+  HWND behind = HWND_TOP;
+  if (aPlacement == eZPlacementBottom)
+    behind = HWND_BOTTOM;
+  else if (aPlacement == eZPlacementBelow && aWidget)
+    behind = (HWND)aWidget->GetNativeData(NS_NATIVE_WINDOW);
+  UINT flags = SWP_NOMOVE | SWP_NOREPOSITION | SWP_NOSIZE;
+  if (!aActivate) flags |= SWP_NOACTIVATE;
+
+  if (!CanTakeFocus() && behind == HWND_TOP) {
+    // Can't place the window to top so place it behind the foreground window
+    // (as long as it is not topmost)
+    HWND wndAfter = ::GetForegroundWindow();
+    if (!wndAfter)
+      behind = HWND_BOTTOM;
+    else if (!(GetWindowLongPtrW(wndAfter, GWL_EXSTYLE) & WS_EX_TOPMOST))
+      behind = wndAfter;
+    flags |= SWP_NOACTIVATE;
+  }
+
+  ::SetWindowPos(mWnd, behind, 0, 0, 0, 0, flags);
+}
+
+static UINT GetCurrentShowCmd(HWND aWnd) {
+  WINDOWPLACEMENT pl;
+  pl.length = sizeof(pl);
+  ::GetWindowPlacement(aWnd, &pl);
+  return pl.showCmd;
+}
+
+// Maximize, minimize or restore the window.
+void nsWindow::SetSizeMode(nsSizeMode aMode) {
+  // If we are still displaying a maximized pre-XUL skeleton UI, ignore the
+  // noise of sizemode changes. Once we have "shown" the window for the first
+  // time (called nsWindow::Show(true), even though the window is already
+  // technically displayed), we will again accept sizemode changes.
+  if (mIsShowingPreXULSkeletonUI && WasPreXULSkeletonUIMaximized()) {
+    return;
+  }
+
+  mFrameState->EnsureSizeMode(aMode);
+}
+
+nsSizeMode nsWindow::SizeMode() { return mFrameState->GetSizeMode(); }
+
+void DoGetWorkspaceID(HWND aWnd, nsAString* aWorkspaceID) {
+  RefPtr<IVirtualDesktopManager> desktopManager = gVirtualDesktopManager;
+  if (!desktopManager || !aWnd) {
+    return;
+  }
+
+  GUID desktop;
+  HRESULT hr = desktopManager->GetWindowDesktopId(aWnd, &desktop);
+  if (FAILED(hr)) {
+    return;
+  }
+
+  RPC_WSTR workspaceIDStr = nullptr;
+  if (UuidToStringW(&desktop, &workspaceIDStr) == RPC_S_OK) {
+    aWorkspaceID->Assign((wchar_t*)workspaceIDStr);
+    RpcStringFreeW(&workspaceIDStr);
+  }
+}
+
+void nsWindow::GetWorkspaceID(nsAString& workspaceID) {
+  // If we have a value cached, use that, but also make sure it is
+  // scheduled to be updated.  If we don't yet have a value, get
+  // one synchronously.
+  auto desktop = mDesktopId.Lock();
+  if (desktop->mID.IsEmpty()) {
+    DoGetWorkspaceID(mWnd, &desktop->mID);
+    desktop->mUpdateIsQueued = false;
+  } else {
+    AsyncUpdateWorkspaceID(*desktop);
+  }
+
+  workspaceID = desktop->mID;
+}
+
+void nsWindow::AsyncUpdateWorkspaceID(Desktop& aDesktop) {
+  struct UpdateWorkspaceIdTask : public Task {
+    explicit UpdateWorkspaceIdTask(nsWindow* aSelf)
+        : Task(Kind::OffMainThreadOnly, EventQueuePriority::Normal),
+          mSelf(aSelf) {}
+
+    TaskResult Run() override {
+      auto desktop = mSelf->mDesktopId.Lock();
+      if (desktop->mUpdateIsQueued) {
+        DoGetWorkspaceID(mSelf->mWnd, &desktop->mID);
+        desktop->mUpdateIsQueued = false;
+      }
+      return TaskResult::Complete;
+    }
+
+#ifdef MOZ_COLLECTING_RUNNABLE_TELEMETRY
+    bool GetName(nsACString& aName) override {
+      aName.AssignLiteral("UpdateWorkspaceIdTask");
+      return true;
+    }
+#endif
+
+    RefPtr<nsWindow> mSelf;
+  };
+
+  if (aDesktop.mUpdateIsQueued) {
+    return;
+  }
+
+  aDesktop.mUpdateIsQueued = true;
+  TaskController::Get()->AddTask(MakeAndAddRef<UpdateWorkspaceIdTask>(this));
+}
+
+void nsWindow::MoveToWorkspace(const nsAString& workspaceID) {
+  RefPtr<IVirtualDesktopManager> desktopManager = gVirtualDesktopManager;
+  if (!desktopManager) {
+    return;
+  }
+
+  GUID desktop;
+  const nsString flat = PromiseFlatString(workspaceID);
+  RPC_WSTR workspaceIDStr = reinterpret_cast<RPC_WSTR>((wchar_t*)flat.get());
+  if (UuidFromStringW(workspaceIDStr, &desktop) == RPC_S_OK) {
+    if (SUCCEEDED(desktopManager->MoveWindowToDesktop(mWnd, desktop))) {
+      auto desktop = mDesktopId.Lock();
+      desktop->mID = workspaceID;
+    }
+  }
+}
+
+void nsWindow::SuppressAnimation(bool aSuppress) {
+  DWORD dwAttribute = aSuppress ? TRUE : FALSE;
+  DwmSetWindowAttribute(mWnd, DWMWA_TRANSITIONS_FORCEDISABLED, &dwAttribute,
+                        sizeof dwAttribute);
+}
+
+// Constrain a potential move to fit onscreen
+// Position (aX, aY) is specified in Windows screen (logical) pixels,
+// except when using per-monitor DPI, in which case it's device pixels.
+void nsWindow::ConstrainPosition(DesktopIntPoint& aPoint) {
+  if (!mIsTopWidgetWindow)  // only a problem for top-level windows
+    return;
+
+  double dpiScale = GetDesktopToDeviceScale().scale;
+
+  // We need to use the window size in the kind of pixels used for window-
+  // manipulation APIs.
+  int32_t logWidth =
+      std::max<int32_t>(NSToIntRound(mBounds.Width() / dpiScale), 1);
+  int32_t logHeight =
+      std::max<int32_t>(NSToIntRound(mBounds.Height() / dpiScale), 1);
+
+  /* get our playing field. use the current screen, or failing that
+  for any reason, use device caps for the default screen. */
+  RECT screenRect;
+
+  nsCOMPtr<nsIScreenManager> screenmgr =
+      do_GetService(sScreenManagerContractID);
+  if (!screenmgr) {
+    return;
+  }
+  nsCOMPtr<nsIScreen> screen;
+  int32_t left, top, width, height;
+
+  screenmgr->ScreenForRect(aPoint.x, aPoint.y, logWidth, logHeight,
+                           getter_AddRefs(screen));
+  if (mFrameState->GetSizeMode() != nsSizeMode_Fullscreen) {
+    // For normalized windows, use the desktop work area.
+    nsresult rv = screen->GetAvailRectDisplayPix(&left, &top, &width, &height);
+    if (NS_FAILED(rv)) {
+      return;
+    }
+  } else {
+    // For full screen windows, use the desktop.
+    nsresult rv = screen->GetRectDisplayPix(&left, &top, &width, &height);
+    if (NS_FAILED(rv)) {
+      return;
+    }
+  }
+  screenRect.left = left;
+  screenRect.right = left + width;
+  screenRect.top = top;
+  screenRect.bottom = top + height;
+
+  if (aPoint.x < screenRect.left)
+    aPoint.x = screenRect.left;
+  else if (aPoint.x >= screenRect.right - logWidth)
+    aPoint.x = screenRect.right - logWidth;
+
+  if (aPoint.y < screenRect.top)
+    aPoint.y = screenRect.top;
+  else if (aPoint.y >= screenRect.bottom - logHeight)
+    aPoint.y = screenRect.bottom - logHeight;
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::Enable, nsIWidget::IsEnabled
+ *
+ * Enabling and disabling the widget.
+ *
+ **************************************************************/
+
+// Enable/disable this component
+void nsWindow::Enable(bool bState) {
+  if (mWnd) {
+    ::EnableWindow(mWnd, bState);
+  }
+}
+
+// Return the current enable state
+bool nsWindow::IsEnabled() const {
+  return !mWnd || (::IsWindowEnabled(mWnd) &&
+                   ::IsWindowEnabled(::GetAncestor(mWnd, GA_ROOT)));
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::SetFocus
+ *
+ * Give the focus to this widget.
+ *
+ **************************************************************/
+
+void nsWindow::SetFocus(Raise aRaise, mozilla::dom::CallerType aCallerType) {
+  if (mWnd) {
+#ifdef WINSTATE_DEBUG_OUTPUT
+    if (mWnd == WinUtils::GetTopLevelHWND(mWnd)) {
+      MOZ_LOG(gWindowsLog, LogLevel::Info,
+              ("*** SetFocus: [  top] raise=%d\n", aRaise == Raise::Yes));
+    } else {
+      MOZ_LOG(gWindowsLog, LogLevel::Info,
+              ("*** SetFocus: [child] raise=%d\n", aRaise == Raise::Yes));
+    }
+#endif
+    // Uniconify, if necessary
+    HWND toplevelWnd = WinUtils::GetTopLevelHWND(mWnd);
+    if (aRaise == Raise::Yes && ::IsIconic(toplevelWnd)) {
+      ::ShowWindow(toplevelWnd, SW_RESTORE);
+    }
+    ::SetFocus(mWnd);
+  }
+}
+
+/**************************************************************
+ *
+ * SECTION: Bounds
+ *
+ * GetBounds, GetClientBounds, GetScreenBounds,
+ * GetRestoredBounds, GetClientOffset, SetNonClientMargins
+ *
+ * Bound calculations.
+ *
+ **************************************************************/
+
+// Return the window's full dimensions in screen coordinates.
+// If the window has a parent, converts the origin to an offset
+// of the parent's screen origin.
+LayoutDeviceIntRect nsWindow::GetBounds() {
+  if (!mWnd) {
+    return mBounds;
+  }
+
+  RECT r;
+  VERIFY(::GetWindowRect(mWnd, &r));
+
+  LayoutDeviceIntRect rect;
+
+  // assign size
+  rect.SizeTo(r.right - r.left, r.bottom - r.top);
+
+  // popup window bounds' are in screen coordinates, not relative to parent
+  // window
+  if (mWindowType == WindowType::Popup) {
+    rect.MoveTo(r.left, r.top);
+    return rect;
+  }
+
+  // chrome on parent:
+  //  ___      5,5   (chrome start)
+  // |  ____   10,10 (client start)
+  // | |  ____ 20,20 (child start)
+  // | | |
+  // 20,20 - 5,5 = 15,15 (??)
+  // minus GetClientOffset:
+  // 15,15 - 5,5 = 10,10
+  //
+  // no chrome on parent:
+  //  ______   10,10 (win start)
+  // |  ____   20,20 (child start)
+  // | |
+  // 20,20 - 10,10 = 10,10
+  //
+  // walking the chain:
+  //  ___      5,5   (chrome start)
+  // |  ___    10,10 (client start)
+  // | |  ___  20,20 (child start)
+  // | | |  __ 30,30 (child start)
+  // | | | |
+  // 30,30 - 20,20 = 10,10 (offset from second child to first)
+  // 20,20 - 5,5 = 15,15 + 10,10 = 25,25 (??)
+  // minus GetClientOffset:
+  // 25,25 - 5,5 = 20,20 (offset from second child to parent client)
+
+  // convert coordinates if parent exists
+  HWND parent = ::GetParent(mWnd);
+  if (parent) {
+    RECT pr;
+    VERIFY(::GetWindowRect(parent, &pr));
+    r.left -= pr.left;
+    r.top -= pr.top;
+    // adjust for chrome
+    nsWindow* pWidget = static_cast<nsWindow*>(GetParent());
+    if (pWidget && pWidget->IsTopLevelWidget()) {
+      LayoutDeviceIntPoint clientOffset = pWidget->GetClientOffset();
+      r.left -= clientOffset.x;
+      r.top -= clientOffset.y;
+    }
+  }
+  rect.MoveTo(r.left, r.top);
+  if (mCompositorSession &&
+      !wr::WindowSizeSanityCheck(rect.width, rect.height)) {
+    gfxCriticalNoteOnce << "Invalid size" << rect << " size mode "
+                        << mFrameState->GetSizeMode();
+  }
+
+  return rect;
+}
+
+// Get this component dimension
+LayoutDeviceIntRect nsWindow::GetClientBounds() {
+  if (!mWnd) {
+    return LayoutDeviceIntRect(0, 0, 0, 0);
+  }
+
+  RECT r;
+  if (!::GetClientRect(mWnd, &r)) {
+    MOZ_ASSERT_UNREACHABLE("unexpected to be called");
+    gfxCriticalNoteOnce << "GetClientRect failed " << ::GetLastError();
+    return mBounds;
+  }
+
+  LayoutDeviceIntRect bounds = GetBounds();
+  LayoutDeviceIntRect rect;
+  rect.MoveTo(bounds.TopLeft() + GetClientOffset());
+  rect.SizeTo(r.right - r.left, r.bottom - r.top);
+  return rect;
+}
+
+// Like GetBounds, but don't offset by the parent
+LayoutDeviceIntRect nsWindow::GetScreenBounds() {
+  if (!mWnd) {
+    return mBounds;
+  }
+
+  RECT r;
+  VERIFY(::GetWindowRect(mWnd, &r));
+
+  return LayoutDeviceIntRect(r.left, r.top, r.right - r.left, r.bottom - r.top);
+}
+
+nsresult nsWindow::GetRestoredBounds(LayoutDeviceIntRect& aRect) {
+  if (SizeMode() == nsSizeMode_Normal) {
+    aRect = GetScreenBounds();
+    return NS_OK;
+  }
+  if (!mWnd) {
+    return NS_ERROR_FAILURE;
+  }
+
+  WINDOWPLACEMENT pl = {sizeof(WINDOWPLACEMENT)};
+  VERIFY(::GetWindowPlacement(mWnd, &pl));
+  const RECT& r = pl.rcNormalPosition;
+
+  HMONITOR monitor = ::MonitorFromWindow(mWnd, MONITOR_DEFAULTTONULL);
+  if (!monitor) {
+    return NS_ERROR_FAILURE;
+  }
+  MONITORINFO mi = {sizeof(MONITORINFO)};
+  VERIFY(::GetMonitorInfo(monitor, &mi));
+
+  aRect.SetRect(r.left, r.top, r.right - r.left, r.bottom - r.top);
+  aRect.MoveBy(mi.rcWork.left - mi.rcMonitor.left,
+               mi.rcWork.top - mi.rcMonitor.top);
+  return NS_OK;
+}
+
+// Return the x,y offset of the client area from the origin of the window. If
+// the window is borderless returns (0,0).
+LayoutDeviceIntPoint nsWindow::GetClientOffset() {
+  if (!mWnd) {
+    return LayoutDeviceIntPoint(0, 0);
+  }
+
+  RECT r1;
+  GetWindowRect(mWnd, &r1);
+  LayoutDeviceIntPoint pt = WidgetToScreenOffset();
+  return LayoutDeviceIntPoint(pt.x - LayoutDeviceIntCoord(r1.left),
+                              pt.y - LayoutDeviceIntCoord(r1.top));
+}
+
+void nsWindow::ResetLayout() {
+  // This will trigger a frame changed event, triggering
+  // nc calc size and a sizemode gecko event.
+  SetWindowPos(mWnd, 0, 0, 0, 0, 0,
+               SWP_FRAMECHANGED | SWP_NOACTIVATE | SWP_NOMOVE |
+                   SWP_NOOWNERZORDER | SWP_NOSIZE | SWP_NOZORDER);
+
+  // If hidden, just send the frame changed event for now.
+  if (!mIsVisible) {
+    return;
+  }
+
+  // Send a gecko size event to trigger reflow.
+  RECT clientRc = {0};
+  GetClientRect(mWnd, &clientRc);
+  OnResize(WinUtils::ToIntRect(clientRc).Size());
+
+  // Invalidate and update
+  Invalidate();
+}
+
+// Internally track the caption status via a window property. Required
+// due to our internal handling of WM_NCACTIVATE when custom client
+// margins are set.
+static const wchar_t kManageWindowInfoProperty[] = L"ManageWindowInfoProperty";
+typedef BOOL(WINAPI* GetWindowInfoPtr)(HWND hwnd, PWINDOWINFO pwi);
+static WindowsDllInterceptor::FuncHookType<GetWindowInfoPtr>
+    sGetWindowInfoPtrStub;
+
+BOOL WINAPI GetWindowInfoHook(HWND hWnd, PWINDOWINFO pwi) {
+  if (!sGetWindowInfoPtrStub) {
+    NS_ASSERTION(FALSE, "Something is horribly wrong in GetWindowInfoHook!");
+    return FALSE;
+  }
+  int windowStatus =
+      reinterpret_cast<LONG_PTR>(GetPropW(hWnd, kManageWindowInfoProperty));
+  // No property set, return the default data.
+  if (!windowStatus) return sGetWindowInfoPtrStub(hWnd, pwi);
+  // Call GetWindowInfo and update dwWindowStatus with our
+  // internally tracked value.
+  BOOL result = sGetWindowInfoPtrStub(hWnd, pwi);
+  if (result && pwi)
+    pwi->dwWindowStatus = (windowStatus == 1 ? 0 : WS_ACTIVECAPTION);
+  return result;
+}
+
+void nsWindow::UpdateGetWindowInfoCaptionStatus(bool aActiveCaption) {
+  if (!mWnd) return;
+
+  sUser32Intercept.Init("user32.dll");
+  sGetWindowInfoPtrStub.Set(sUser32Intercept, "GetWindowInfo",
+                            &GetWindowInfoHook);
+  if (!sGetWindowInfoPtrStub) {
+    return;
+  }
+
+  // Update our internally tracked caption status
+  SetPropW(mWnd, kManageWindowInfoProperty,
+           reinterpret_cast<HANDLE>(static_cast<INT_PTR>(aActiveCaption) + 1));
+}
+
+#define DWMWA_USE_IMMERSIVE_DARK_MODE_BEFORE_20H1 19
+#define DWMWA_USE_IMMERSIVE_DARK_MODE 20
+
+void nsWindow::UpdateDarkModeToolbar() {
+  PreferenceSheet::EnsureInitialized();
+  BOOL dark = PreferenceSheet::ColorSchemeForChrome() == ColorScheme::Dark;
+  DwmSetWindowAttribute(mWnd, DWMWA_USE_IMMERSIVE_DARK_MODE_BEFORE_20H1, &dark,
+                        sizeof dark);
+  DwmSetWindowAttribute(mWnd, DWMWA_USE_IMMERSIVE_DARK_MODE, &dark,
+                        sizeof dark);
+}
+
+LayoutDeviceIntMargin nsWindow::NormalWindowNonClientOffset() const {
+  LayoutDeviceIntMargin nonClientOffset;
+
+  // We're dealing with a "normal" window (not maximized, minimized, or
+  // fullscreen), so process `mNonClientMargins` and set `mNonClientOffset`
+  // accordingly.
+  //
+  // Setting `mNonClientOffset` to 0 has the effect of leaving the default
+  // frame intact.  Setting it to a value greater than 0 reduces the frame
+  // size by that amount.
+
+  if (mNonClientMargins.top > 0) {
+    nonClientOffset.top = std::min(mCaptionHeight, mNonClientMargins.top);
+  } else if (mNonClientMargins.top == 0) {
+    nonClientOffset.top = mCaptionHeight;
+  } else {
+    nonClientOffset.top = 0;
+  }
+
+  if (mNonClientMargins.bottom > 0) {
+    nonClientOffset.bottom =
+        std::min(mVertResizeMargin, mNonClientMargins.bottom);
+  } else if (mNonClientMargins.bottom == 0) {
+    nonClientOffset.bottom = mVertResizeMargin;
+  } else {
+    nonClientOffset.bottom = 0;
+  }
+
+  if (mNonClientMargins.left > 0) {
+    nonClientOffset.left = std::min(mHorResizeMargin, mNonClientMargins.left);
+  } else if (mNonClientMargins.left == 0) {
+    nonClientOffset.left = mHorResizeMargin;
+  } else {
+    nonClientOffset.left = 0;
+  }
+
+  if (mNonClientMargins.right > 0) {
+    nonClientOffset.right = std::min(mHorResizeMargin, mNonClientMargins.right);
+  } else if (mNonClientMargins.right == 0) {
+    nonClientOffset.right = mHorResizeMargin;
+  } else {
+    nonClientOffset.right = 0;
+  }
+  return nonClientOffset;
+}
+
+/**
+ * Called when the window layout changes: full screen mode transitions,
+ * theme changes, and composition changes. Calculates the new non-client
+ * margins and fires off a frame changed event, which triggers an nc calc
+ * size windows event, kicking the changes in.
+ *
+ * The offsets calculated here are based on the value of `mNonClientMargins`
+ * which is specified in the "chromemargins" attribute of the window.  For
+ * each margin, the value specified has the following meaning:
+ *    -1 - leave the default frame in place
+ *     0 - remove the frame
+ *    >0 - frame size equals min(0, (default frame size - margin value))
+ *
+ * This function calculates and populates `mNonClientOffset`.
+ * In our processing of `WM_NCCALCSIZE`, the frame size will be calculated
+ * as (default frame size - offset).  For example, if the left frame should
+ * be 1 pixel narrower than the default frame size, `mNonClientOffset.left`
+ * will equal 1.
+ *
+ * For maximized, fullscreen, and minimized windows, the values stored in
+ * `mNonClientMargins` are ignored, and special processing takes place.
+ *
+ * For non-glass windows, we only allow frames to be their default size
+ * or removed entirely.
+ */
+bool nsWindow::UpdateNonClientMargins(bool aReflowWindow) {
+  if (!mCustomNonClient) {
+    return false;
+  }
+
+  const nsSizeMode sizeMode = mFrameState->GetSizeMode();
+
+  bool hasCaption =
+      bool(mBorderStyle & (BorderStyle::All | BorderStyle::Title |
+                           BorderStyle::Menu | BorderStyle::Default));
+
+  float dpi = GetDPI();
+
+  // mCaptionHeight is the default size of the NC area at
+  // the top of the window. If the window has a caption,
+  // the size is calculated as the sum of:
+  //      SM_CYFRAME        - The thickness of the sizing border
+  //                          around a resizable window
+  //      SM_CXPADDEDBORDER - The amount of border padding
+  //                          for captioned windows
+  //      SM_CYCAPTION      - The height of the caption area
+  //
+  // If the window does not have a caption, mCaptionHeight will be equal to
+  // `WinUtils::GetSystemMetricsForDpi(SM_CYFRAME, dpi)`
+  mCaptionHeight =
+      WinUtils::GetSystemMetricsForDpi(SM_CYFRAME, dpi) +
+      (hasCaption ? WinUtils::GetSystemMetricsForDpi(SM_CYCAPTION, dpi) +
+                        WinUtils::GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi)
+                  : 0);
+  if (!mUseResizeMarginOverrides) {
+    // mHorResizeMargin is the size of the default NC areas on the
+    // left and right sides of our window.  It is calculated as
+    // the sum of:
+    //      SM_CXFRAME        - The thickness of the sizing border
+    //      SM_CXPADDEDBORDER - The amount of border padding
+    //                          for captioned windows
+    //
+    // If the window does not have a caption, mHorResizeMargin will be equal to
+    // `WinUtils::GetSystemMetricsForDpi(SM_CXFRAME, dpi)`
+    mHorResizeMargin =
+        WinUtils::GetSystemMetricsForDpi(SM_CXFRAME, dpi) +
+        (hasCaption ? WinUtils::GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi)
+                    : 0);
+
+    // mVertResizeMargin is the size of the default NC area at the
+    // bottom of the window. It is calculated as the sum of:
+    //      SM_CYFRAME        - The thickness of the sizing border
+    //      SM_CXPADDEDBORDER - The amount of border padding
+    //                          for captioned windows.
+    //
+    // If the window does not have a caption, mVertResizeMargin will be equal to
+    // `WinUtils::GetSystemMetricsForDpi(SM_CYFRAME, dpi)`
+    mVertResizeMargin =
+        WinUtils::GetSystemMetricsForDpi(SM_CYFRAME, dpi) +
+        (hasCaption ? WinUtils::GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi)
+                    : 0);
+  }
+
+  if (sizeMode == nsSizeMode_Minimized) {
+    // Use default frame size for minimized windows
+    mNonClientOffset.top = 0;
+    mNonClientOffset.left = 0;
+    mNonClientOffset.right = 0;
+    mNonClientOffset.bottom = 0;
+  } else if (sizeMode == nsSizeMode_Fullscreen) {
+    // Remove the default frame from the top of our fullscreen window.  This
+    // makes the whole caption part of our client area, allowing us to draw
+    // in the whole caption area.  Additionally remove the default frame from
+    // the left, right, and bottom.
+    mNonClientOffset.top = mCaptionHeight;
+    mNonClientOffset.bottom = mVertResizeMargin;
+    mNonClientOffset.left = mHorResizeMargin;
+    mNonClientOffset.right = mHorResizeMargin;
+  } else if (sizeMode == nsSizeMode_Maximized) {
+    // We make the entire frame part of the client area. We leave the default
+    // frame sizes for left, right and bottom since Windows will automagically
+    // position the edges "offscreen" for maximized windows.
+    int verticalResize =
+        WinUtils::GetSystemMetricsForDpi(SM_CYFRAME, dpi) +
+        (hasCaption ? WinUtils::GetSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi)
+                    : 0);
+
+    mNonClientOffset.top = mCaptionHeight - verticalResize;
+    mNonClientOffset.bottom = 0;
+    mNonClientOffset.left = 0;
+    mNonClientOffset.right = 0;
+
+    mozilla::Maybe<UINT> maybeEdge = GetHiddenTaskbarEdge();
+    if (maybeEdge) {
+      auto edge = maybeEdge.value();
+      if (ABE_LEFT == edge) {
+        mNonClientOffset.left -= kHiddenTaskbarSize;
+      } else if (ABE_RIGHT == edge) {
+        mNonClientOffset.right -= kHiddenTaskbarSize;
+      } else if (ABE_BOTTOM == edge || ABE_TOP == edge) {
+        mNonClientOffset.bottom -= kHiddenTaskbarSize;
+      }
+
+      // When we are drawing the non-client region, we need
+      // to clear the portion of the NC region that is exposed by the
+      // hidden taskbar.  As above, we clear the bottom of the NC region
+      // when the taskbar is at the top of the screen.
+      UINT clearEdge = (edge == ABE_TOP) ? ABE_BOTTOM : edge;
+      mClearNCEdge = Some(clearEdge);
+    }
+  } else {
+    mNonClientOffset = NormalWindowNonClientOffset();
+  }
+
+  if (aReflowWindow) {
+    // Force a reflow of content based on the new client
+    // dimensions.
+    ResetLayout();
+  }
+
+  return true;
+}
+
+nsresult nsWindow::SetNonClientMargins(const LayoutDeviceIntMargin& margins) {
+  if (!mIsTopWidgetWindow || mBorderStyle == BorderStyle::None)
+    return NS_ERROR_INVALID_ARG;
+
+  if (mHideChrome) {
+    mFutureMarginsOnceChromeShows = margins;
+    mFutureMarginsToUse = true;
+    return NS_OK;
+  }
+  mFutureMarginsToUse = false;
+
+  // Request for a reset
+  if (margins.top == -1 && margins.left == -1 && margins.right == -1 &&
+      margins.bottom == -1) {
+    mCustomNonClient = false;
+    mNonClientMargins = margins;
+    // Force a reflow of content based on the new client
+    // dimensions.
+    ResetLayout();
+
+    int windowStatus =
+        reinterpret_cast<LONG_PTR>(GetPropW(mWnd, kManageWindowInfoProperty));
+    if (windowStatus) {
+      ::SendMessageW(mWnd, WM_NCACTIVATE, 1 != windowStatus, 0);
+    }
+
+    return NS_OK;
+  }
+
+  if (margins.top < -1 || margins.bottom < -1 || margins.left < -1 ||
+      margins.right < -1)
+    return NS_ERROR_INVALID_ARG;
+
+  mNonClientMargins = margins;
+  mCustomNonClient = true;
+  if (!UpdateNonClientMargins()) {
+    NS_WARNING("UpdateNonClientMargins failed!");
+    return NS_OK;
+  }
+
+  return NS_OK;
+}
+
+void nsWindow::SetResizeMargin(mozilla::LayoutDeviceIntCoord aResizeMargin) {
+  mUseResizeMarginOverrides = true;
+  mHorResizeMargin = aResizeMargin;
+  mVertResizeMargin = aResizeMargin;
+  UpdateNonClientMargins();
+}
+
+void nsWindow::InvalidateNonClientRegion() {
+  // +-+-----------------------+-+
+  // | | app non-client chrome | |
+  // | +-----------------------+ |
+  // | |   app client chrome   | | }
+  // | +-----------------------+ | }
+  // | |      app content      | | } area we don't want to invalidate
+  // | +-----------------------+ | }
+  // | |   app client chrome   | | }
+  // | +-----------------------+ |
+  // +---------------------------+ <
+  //  ^                         ^    windows non-client chrome
+  // client area = app *
+  RECT rect;
+  GetWindowRect(mWnd, &rect);
+  MapWindowPoints(nullptr, mWnd, (LPPOINT)&rect, 2);
+  HRGN winRgn = CreateRectRgnIndirect(&rect);
+
+  // Subtract app client chrome and app content leaving
+  // windows non-client chrome and app non-client chrome
+  // in winRgn.
+  GetWindowRect(mWnd, &rect);
+  rect.top += mCaptionHeight;
+  rect.right -= mHorResizeMargin;
+  rect.bottom -= mVertResizeMargin;
+  rect.left += mHorResizeMargin;
+  MapWindowPoints(nullptr, mWnd, (LPPOINT)&rect, 2);
+  HRGN clientRgn = CreateRectRgnIndirect(&rect);
+  CombineRgn(winRgn, winRgn, clientRgn, RGN_DIFF);
+  DeleteObject(clientRgn);
+
+  // triggers ncpaint and paint events for the two areas
+  RedrawWindow(mWnd, nullptr, winRgn, RDW_FRAME | RDW_INVALIDATE);
+  DeleteObject(winRgn);
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::SetBackgroundColor
+ *
+ * Sets the window background paint color.
+ *
+ **************************************************************/
+
+void nsWindow::SetBackgroundColor(const nscolor& aColor) {
+  if (mBrush) ::DeleteObject(mBrush);
+
+  mBrush = ::CreateSolidBrush(NSRGB_2_COLOREF(aColor));
+  if (mWnd != nullptr) {
+    ::SetClassLongPtrW(mWnd, GCLP_HBRBACKGROUND, (LONG_PTR)mBrush);
+  }
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::SetCursor
+ *
+ * SetCursor and related utilities for manging cursor state.
+ *
+ **************************************************************/
+
+// Set this component cursor
+static HCURSOR CursorFor(nsCursor aCursor) {
+  switch (aCursor) {
+    case eCursor_select:
+      return ::LoadCursor(nullptr, IDC_IBEAM);
+    case eCursor_wait:
+      return ::LoadCursor(nullptr, IDC_WAIT);
+    case eCursor_hyperlink:
+      return ::LoadCursor(nullptr, IDC_HAND);
+    case eCursor_standard:
+    case eCursor_context_menu:  // XXX See bug 258960.
+      return ::LoadCursor(nullptr, IDC_ARROW);
+
+    case eCursor_n_resize:
+    case eCursor_s_resize:
+      return ::LoadCursor(nullptr, IDC_SIZENS);
+
+    case eCursor_w_resize:
+    case eCursor_e_resize:
+      return ::LoadCursor(nullptr, IDC_SIZEWE);
+
+    case eCursor_nw_resize:
+    case eCursor_se_resize:
+      return ::LoadCursor(nullptr, IDC_SIZENWSE);
+
+    case eCursor_ne_resize:
+    case eCursor_sw_resize:
+      return ::LoadCursor(nullptr, IDC_SIZENESW);
+
+    case eCursor_crosshair:
+      return ::LoadCursor(nullptr, IDC_CROSS);
+
+    case eCursor_move:
+      return ::LoadCursor(nullptr, IDC_SIZEALL);
+
+    case eCursor_help:
+      return ::LoadCursor(nullptr, IDC_HELP);
+
+    case eCursor_copy:  // CSS3
+      return ::LoadCursor(nsToolkit::mDllInstance, MAKEINTRESOURCE(IDC_COPY));
+
+    case eCursor_alias:
+      return ::LoadCursor(nsToolkit::mDllInstance, MAKEINTRESOURCE(IDC_ALIAS));
+
+    case eCursor_cell:
+      return ::LoadCursor(nsToolkit::mDllInstance, MAKEINTRESOURCE(IDC_CELL));
+    case eCursor_grab:
+      return ::LoadCursor(nsToolkit::mDllInstance, MAKEINTRESOURCE(IDC_GRAB));
+
+    case eCursor_grabbing:
+      return ::LoadCursor(nsToolkit::mDllInstance,
+                          MAKEINTRESOURCE(IDC_GRABBING));
+
+    case eCursor_spinning:
+      return ::LoadCursor(nullptr, IDC_APPSTARTING);
+
+    case eCursor_zoom_in:
+      return ::LoadCursor(nsToolkit::mDllInstance, MAKEINTRESOURCE(IDC_ZOOMIN));
+
+    case eCursor_zoom_out:
+      return ::LoadCursor(nsToolkit::mDllInstance,
+                          MAKEINTRESOURCE(IDC_ZOOMOUT));
+
+    case eCursor_not_allowed:
+    case eCursor_no_drop:
+      return ::LoadCursor(nullptr, IDC_NO);
+
+    case eCursor_col_resize:
+      return ::LoadCursor(nsToolkit::mDllInstance,
+                          MAKEINTRESOURCE(IDC_COLRESIZE));
+
+    case eCursor_row_resize:
+      return ::LoadCursor(nsToolkit::mDllInstance,
+                          MAKEINTRESOURCE(IDC_ROWRESIZE));
+
+    case eCursor_vertical_text:
+      return ::LoadCursor(nsToolkit::mDllInstance,
+                          MAKEINTRESOURCE(IDC_VERTICALTEXT));
+
+    case eCursor_all_scroll:
+      // XXX not 100% appropriate perhaps
+      return ::LoadCursor(nullptr, IDC_SIZEALL);
+
+    case eCursor_nesw_resize:
+      return ::LoadCursor(nullptr, IDC_SIZENESW);
+
+    case eCursor_nwse_resize:
+      return ::LoadCursor(nullptr, IDC_SIZENWSE);
+
+    case eCursor_ns_resize:
+      return ::LoadCursor(nullptr, IDC_SIZENS);
+
+    case eCursor_ew_resize:
+      return ::LoadCursor(nullptr, IDC_SIZEWE);
+
+    case eCursor_none:
+      return ::LoadCursor(nsToolkit::mDllInstance, MAKEINTRESOURCE(IDC_NONE));
+
+    default:
+      NS_ERROR("Invalid cursor type");
+      return nullptr;
+  }
+}
+
+static HCURSOR CursorForImage(const nsIWidget::Cursor& aCursor,
+                              CSSToLayoutDeviceScale aScale) {
+  if (!aCursor.IsCustom()) {
+    return nullptr;
+  }
+
+  nsIntSize size = nsIWidget::CustomCursorSize(aCursor);
+
+  // Reject cursors greater than 128 pixels in either direction, to prevent
+  // spoofing.
+  // XXX ideally we should rescale. Also, we could modify the API to
+  // allow trusted content to set larger cursors.
+  if (size.width > 128 || size.height > 128) {
+    return nullptr;
+  }
+
+  LayoutDeviceIntSize layoutSize =
+      RoundedToInt(CSSIntSize(size.width, size.height) * aScale);
+  LayoutDeviceIntPoint hotspot =
+      RoundedToInt(CSSIntPoint(aCursor.mHotspotX, aCursor.mHotspotY) * aScale);
+  HCURSOR cursor;
+  nsresult rv = nsWindowGfx::CreateIcon(aCursor.mContainer, true, hotspot,
+                                        layoutSize, &cursor);
+  if (NS_FAILED(rv)) {
+    return nullptr;
+  }
+
+  return cursor;
+}
+
+void nsWindow::SetCursor(const Cursor& aCursor) {
+  static HCURSOR sCurrentHCursor = nullptr;
+  static bool sCurrentHCursorIsCustom = false;
+
+  mCursor = aCursor;
+
+  if (sCurrentCursor == aCursor && sCurrentHCursor && !mUpdateCursor) {
+    // Cursors in windows are global, so even if our mUpdateCursor flag is
+    // false we always need to make sure the Windows cursor is up-to-date,
+    // since stuff like native drag and drop / resizers code can mutate it
+    // outside of this method.
+    ::SetCursor(sCurrentHCursor);
+    return;
+  }
+
+  mUpdateCursor = false;
+
+  if (sCurrentHCursorIsCustom) {
+    ::DestroyIcon(sCurrentHCursor);
+  }
+  sCurrentHCursor = nullptr;
+  sCurrentHCursorIsCustom = false;
+  sCurrentCursor = aCursor;
+
+  HCURSOR cursor = nullptr;
+  if (mCustomCursorAllowed) {
+    cursor = CursorForImage(aCursor, GetDefaultScale());
+  }
+  bool custom = false;
+  if (cursor) {
+    custom = true;
+  } else {
+    cursor = CursorFor(aCursor.mDefaultCursor);
+  }
+
+  if (!cursor) {
+    return;
+  }
+
+  sCurrentHCursor = cursor;
+  sCurrentHCursorIsCustom = custom;
+  ::SetCursor(cursor);
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::Get/SetTransparencyMode
+ *
+ * Manage the transparency mode of the window containing this
+ * widget. Only works for popup and dialog windows when the
+ * Desktop Window Manager compositor is not enabled.
+ *
+ **************************************************************/
+
+TransparencyMode nsWindow::GetTransparencyMode() {
+  return GetTopLevelWindow(true)->GetWindowTranslucencyInner();
+}
+
+void nsWindow::SetTransparencyMode(TransparencyMode aMode) {
+  nsWindow* window = GetTopLevelWindow(true);
+  MOZ_ASSERT(window);
+
+  if (!window || window->DestroyCalled()) {
+    return;
+  }
+
+  window->SetWindowTranslucencyInner(aMode);
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::UpdateWindowDraggingRegion
+ *
+ * For setting the draggable titlebar region from CSS
+ * with -moz-window-dragging: drag.
+ *
+ **************************************************************/
+
+void nsWindow::UpdateWindowDraggingRegion(
+    const LayoutDeviceIntRegion& aRegion) {
+  if (mDraggableRegion != aRegion) {
+    mDraggableRegion = aRegion;
+  }
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::HideWindowChrome
+ *
+ * Show or hide window chrome.
+ *
+ **************************************************************/
+
+void nsWindow::HideWindowChrome(bool aShouldHide) {
+  HWND hwnd = WinUtils::GetTopLevelHWND(mWnd, true);
+  if (!WinUtils::GetNSWindowPtr(hwnd)) {
+    NS_WARNING("Trying to hide window decorations in an embedded context");
+    return;
+  }
+
+  if (mHideChrome == aShouldHide) return;
+
+  DWORD_PTR style, exStyle;
+  mHideChrome = aShouldHide;
+  if (aShouldHide) {
+    DWORD_PTR tempStyle = ::GetWindowLongPtrW(hwnd, GWL_STYLE);
+    DWORD_PTR tempExStyle = ::GetWindowLongPtrW(hwnd, GWL_EXSTYLE);
+
+    style = tempStyle & ~(WS_CAPTION | WS_THICKFRAME);
+    exStyle = tempExStyle & ~(WS_EX_DLGMODALFRAME | WS_EX_WINDOWEDGE |
+                              WS_EX_CLIENTEDGE | WS_EX_STATICEDGE);
+
+    mOldStyle = tempStyle;
+    mOldExStyle = tempExStyle;
+  } else {
+    if (!mOldStyle || !mOldExStyle) {
+      mOldStyle = ::GetWindowLongPtrW(hwnd, GWL_STYLE);
+      mOldExStyle = ::GetWindowLongPtrW(hwnd, GWL_EXSTYLE);
+    }
+
+    style = mOldStyle;
+    exStyle = mOldExStyle;
+    if (mFutureMarginsToUse) {
+      SetNonClientMargins(mFutureMarginsOnceChromeShows);
+    }
+  }
+
+  VERIFY_WINDOW_STYLE(style);
+  ::SetWindowLongPtrW(hwnd, GWL_STYLE, style);
+  ::SetWindowLongPtrW(hwnd, GWL_EXSTYLE, exStyle);
+}
+
+/**************************************************************
+ *
+ * SECTION: nsWindow::Invalidate
+ *
+ * Invalidate an area of the client for painting.
+ *
+ **************************************************************/
+
+// Invalidate this component visible area
+void nsWindow::Invalidate(bool aEraseBackground, bool aUpdateNCArea,
+                          bool aIncludeChildren) {
+  if (!mWnd) {
+    return;
+  }
+
+#ifdef WIDGET_DEBUG_OUTPUT
+  debug_DumpInvalidate(stdout, this, nullptr, "noname", (int32_t)mWnd);
+#endif  // WIDGET_DEBUG_OUTPUT
+
+  DWORD flags = RDW_INVALIDATE;
+  if (aEraseBackground) {
+    flags |= RDW_ERASE;
+  }
+  if (aUpdateNCArea) {
+    flags |= RDW_FRAME;
+  }
+  if (aIncludeChildren) {
+    flags |= RDW_ALLCHILDREN;
+  }
+
+  VERIFY(::RedrawWindow(mWnd, nullptr, nullptr, flags));
+}
+
+// Invalidate this component visible area
+void nsWindow::Invalidate(const LayoutDeviceIntRect& aRect) {
+  if (mWnd) {
+#ifdef WIDGET_DEBUG_OUTPUT
+    debug_DumpInvalidate(stdout, this, &aRect, "noname", (int32_t)mWnd);
+#endif  // WIDGET_DEBUG_OUTPUT
+
+    RECT rect;
+
+    rect.left = aRect.X();
+    rect.top = aRect.Y();
+    rect.right = aRect.XMost();
+    rect.bottom = aRect.YMost();
+
+    VERIFY(::InvalidateRect(mWnd, &rect, FALSE));
+  }
+}
+
+static LRESULT CALLBACK FullscreenTransitionWindowProc(HWND hWnd, UINT uMsg,
+                                                       WPARAM wParam,
+                                                       LPARAM lParam) {
+  switch (uMsg) {
+    case WM_FULLSCREEN_TRANSITION_BEFORE:
+    case WM_FULLSCREEN_TRANSITION_AFTER: {
+      DWORD duration = (DWORD)lParam;
+      DWORD flags = AW_BLEND;
+      if (uMsg == WM_FULLSCREEN_TRANSITION_AFTER) {
+        flags |= AW_HIDE;
+      }
+      ::AnimateWindow(hWnd, duration, flags);
+      // The message sender should have added ref for us.
+      NS_DispatchToMainThread(
+          already_AddRefed<nsIRunnable>((nsIRunnable*)wParam));
+      break;
+    }
+    case WM_DESTROY:
+      ::PostQuitMessage(0);
+      break;
+    default:
+      return ::DefWindowProcW(hWnd, uMsg, wParam, lParam);
+  }
+  return 0;
+}
+
+struct FullscreenTransitionInitData {
+  LayoutDeviceIntRect mBounds;
+  HANDLE mSemaphore;
+  HANDLE mThread;
+  HWND mWnd;
+
+  FullscreenTransitionInitData()
+      : mSemaphore(nullptr), mThread(nullptr), mWnd(nullptr) {}
+
+  ~FullscreenTransitionInitData() {
+    if (mSemaphore) {
+      ::CloseHandle(mSemaphore);
+    }
+    if (mThread) {
+      ::CloseHandle(mThread);
+    }
+  }
+};
+
+static DWORD WINAPI FullscreenTransitionThreadProc(LPVOID lpParam) {
+  // Initialize window class
+  static bool sInitialized = false;
+  if (!sInitialized) {
+    WNDCLASSW wc = {};
+    wc.lpfnWndProc = ::FullscreenTransitionWindowProc;
+    wc.hInstance = nsToolkit::mDllInstance;
+    wc.hbrBackground = ::CreateSolidBrush(RGB(0, 0, 0));
+    wc.lpszClassName = kClassNameTransition;
+    ::RegisterClassW(&wc);
+    sInitialized = true;
+  }
+
+  auto data = static_cast<FullscreenTransitionInitData*>(lpParam);
+  HWND wnd = ::CreateWindowW(kClassNameTransition, L"", 0, 0, 0, 0, 0, nullptr,
+                             nullptr, nsToolkit::mDllInstance, nullptr);
+  if (!wnd) {
+    ::ReleaseSemaphore(data->mSemaphore, 1, nullptr);
+    return 0;
+  }
+
+  // Since AnimateWindow blocks the thread of the transition window,
+  // we need to hide the cursor for that window, otherwise the system
+  // would show the busy pointer to the user.
+  ::ShowCursor(false);
+  ::SetWindowLongW(wnd, GWL_STYLE, 0);
+  ::SetWindowLongW(
+      wnd, GWL_EXSTYLE,
+      WS_EX_LAYERED | WS_EX_TRANSPARENT | WS_EX_TOOLWINDOW | WS_EX_NOACTIVATE);
+  ::SetWindowPos(wnd, HWND_TOPMOST, data->mBounds.X(), data->mBounds.Y(),
+                 data->mBounds.Width(), data->mBounds.Height(), 0);
+  data->mWnd = wnd;
+  ::ReleaseSemaphore(data->mSemaphore, 1, nullptr);
+  // The initialization data may no longer be valid
+  // after we release the semaphore.
+  data = nullptr;
+
+  MSG msg;
+  while (::GetMessageW(&msg, nullptr, 0, 0)) {
+    ::TranslateMessage(&msg);
+    ::DispatchMessage(&msg);
+  }
+  ::ShowCursor(true);
+  ::DestroyWindow(wnd);
+  return 0;
+}
+
+class FullscreenTransitionData final : public nsISupports {
+ public:
+  NS_DECL_ISUPPORTS
+
+  explicit FullscreenTransitionData(HWND aWnd) : mWnd(aWnd) {
+    MOZ_ASSERT(NS_IsMainThread(),
+               "FullscreenTransitionData "
+               "should be constructed in the main thread");
+  }
+
+  const HWND mWnd;
+
+ private:
+  ~FullscreenTransitionData() {
+    MOZ_ASSERT(NS_IsMainThread(),
+               "FullscreenTransitionData "
+               "should be deconstructed in the main thread");
+    ::PostMessageW(mWnd, WM_DESTROY, 0, 0);
+  }
+};
+
+NS_IMPL_ISUPPORTS0(FullscreenTransitionData)
+
+/* virtual */
+bool nsWindow::PrepareForFullscreenTransition(nsISupports** aData) {
+  FullscreenTransitionInitData initData;
+  nsCOMPtr<nsIScreen> screen = GetWidgetScreen();
+  const DesktopIntRect rect = screen->GetRectDisplayPix();
+  MOZ_ASSERT(BoundsUseDesktopPixels(),
+             "Should only be called on top-level window");
+  initData.mBounds =
+      LayoutDeviceIntRect::Round(rect * GetDesktopToDeviceScale());
+
+  // Create a semaphore for synchronizing the window handle which will
+  // be created by the transition thread and used by the main thread for
+  // posting the transition messages.
+  initData.mSemaphore = ::CreateSemaphore(nullptr, 0, 1, nullptr);
+  if (initData.mSemaphore) {
+    initData.mThread = ::CreateThread(
+        nullptr, 0, FullscreenTransitionThreadProc, &initData, 0, nullptr);
+    if (initData.mThread) {
+      ::WaitForSingleObject(initData.mSemaphore, INFINITE);
+    }
+  }
+  if (!initData.mWnd) {
+    return false;
+  }
+
+  mTransitionWnd = initData.mWnd;
+
+  auto data = new FullscreenTransitionData(initData.mWnd);
+  *aData = data;
+  NS_ADDREF(data);
+  return true;
+}
+
+/* virtual */
+void nsWindow::PerformFullscreenTransition(FullscreenTransitionStage aStage,
+                                           uint16_t aDuration,
+                                           nsISupports* aData,
+                                           nsIRunnable* aCallback) {
+  auto data = static_cast<FullscreenTransitionData*>(aData);
+  nsCOMPtr<nsIRunnable> callback = aCallback;
+  UINT msg = aStage == eBeforeFullscreenToggle ? WM_FULLSCREEN_TRANSITION_BEFORE
+                                               : WM_FULLSCREEN_TRANSITION_AFTER;
+  WPARAM wparam = (WPARAM)callback.forget().take();
+  ::PostMessage(data->mWnd, msg, wparam, (LPARAM)aDuration);
+}
+
+/* virtual */
+void nsWindow::CleanupFullscreenTransition() {
+  MOZ_ASSERT(NS_IsMainThread(),
+             "CleanupFullscreenTransition "
+             "should only run on the main thread");
+
+  mTransitionWnd = nullptr;
+}
+
+void nsWindow::TryDwmResizeHack() {
+  // The "DWM resize hack", aka the "fullscreen resize hack", is a workaround
+  // for DWM's occasional and not-entirely-predictable failure to update its
+  // internal state when the client area of a window changes without changing
+  // the window size. The effect of this is that DWM will clip the content of
+  // the window to its former client area.
+  //
+  // It is not known under what circumstances the bug will trigger. Windows 11
+  // is known to be required, but many Windows 11 machines do not exhibit the
+  // issue. Even machines that _do_ exhibit it will sometimes not do so when
+  // apparently-irrelevant changes are made to the configuration. (See bug
+  // 1763981.)
+  //
+  // The bug is triggered by Firefox when a maximized window (which has window
+  // decorations) becomes fullscreen (which doesn't). To work around this, if we
+  // think it may occur, we "flicker-resize" the relevant window -- that is, we
+  // reduce its height by 1px, then restore it. This causes DWM to acquire the
+  // new client-area metrics.
+  //
+  // Note that, in particular, this bug will not occur when using a separate
+  // compositor window, as our compositor windows never have any nonclient area.
+  //
+  // This is admittedly a sledgehammer where a screwdriver should suffice.
+
+  // ---------------------------------------------------------------------------
+
+  // Regardless of preferences or heuristics, only apply the hack if this is the
+  // first time we've entered fullscreen across the entire Firefox session.
+  // (Subsequent transitions to fullscreen, even with different windows, don't
+  // appear to induce the bug.)
+  {
+    // (main thread only; `atomic` not needed)
+    static bool sIsFirstFullscreenEntry = true;
+    bool isFirstFullscreenEntry = sIsFirstFullscreenEntry;
+    sIsFirstFullscreenEntry = false;
+    if (MOZ_LIKELY(!isFirstFullscreenEntry)) {
+      return;
+    }
+    MOZ_LOG(gWindowsLog, LogLevel::Verbose,
+            ("%s: first fullscreen entry", __PRETTY_FUNCTION__));
+  }
+
+  // Check whether to try to apply the DWM resize hack, based on the override
+  // pref and/or some internal heuristics.
+  {
+    const auto hackApplicationHeuristics = [&]() -> bool {
+      // The bug has only been seen under Windows 11. (At time of writing, this
+      // is the latest version of Windows.)
+      if (!IsWin11OrLater()) {
+        return false;
+      }
+
+      KnowsCompositor const* const kc = mWindowRenderer->AsKnowsCompositor();
+      // This should never happen...
+      MOZ_ASSERT(kc);
+      // ... so if it does, we are in uncharted territory: don't apply the hack.
+      if (!kc) {
+        return false;
+      }
+
+      // The bug doesn't occur when we're using a separate compositor window
+      // (since the compositor window always comprises exactly its client area,
+      // with no non-client border).
+      if (kc->GetUseCompositorWnd()) {
+        return false;
+      }
+
+      // Otherwise, apply the hack.
+      return true;
+    };
+
+    // Figure out whether or not we should perform the hack, and -- arguably
+    // more importantly -- log that decision.
+    bool const shouldApplyHack = [&]() {
+      enum Reason : bool { Pref, Heuristics };
+      auto const msg = [&](bool decision, Reason reason) -> bool {
+        MOZ_LOG(gWindowsLog, LogLevel::Verbose,
+                ("%s %s per %s", decision ? "applying" : "skipping",
+                 "DWM resize hack", reason == Pref ? "pref" : "heuristics"));
+        return decision;
+      };
+      switch (StaticPrefs::widget_windows_apply_dwm_resize_hack()) {
+        case 0:
+          return msg(false, Pref);
+        case 1:
+          return msg(true, Pref);
+        default:  // treat all other values as `auto`
+          return msg(hackApplicationHeuristics(), Heuristics);
+      }
+    }();
+
+    if (!shouldApplyHack) {
+      return;
+    }
+  }
+
+  // The DWM bug is believed to involve a race condition: some users have
+  // reported that setting a custom theme or adding unused command-line
+  // parameters sometimes causes the bug to vanish.
+  //
+  // Out of an abundance of caution, we therefore apply the hack in a later
+  // event, rather than inline.
+  NS_DispatchToMainThread(NS_NewRunnableFunction(
+      "nsWindow::TryFullscreenResizeHack", [self = RefPtr(this)]() {
+        HWND const hwnd = self->GetWindowHandle();
+
+        if (self->mFrameState->GetSizeMode() != nsSizeMode_Fullscreen) {
+          MOZ_LOG(gWindowsLog, mozilla::LogLevel::Info,
+                  ("DWM resize hack: window no longer fullscreen; aborting"));
+          return;
+        }
+
+        RECT origRect;
+        if (!::GetWindowRect(hwnd, &origRect)) {
+          MOZ_LOG(gWindowsLog, mozilla::LogLevel::Error,
+                  ("DWM resize hack: could not get window size?!"));
+          return;
+        }
+        LONG const x = origRect.left;
+        LONG const y = origRect.top;
+        LONG const width = origRect.right - origRect.left;
+        LONG const height = origRect.bottom - origRect.top;
+
+        MOZ_DIAGNOSTIC_ASSERT(!self->mIsPerformingDwmFlushHack);
+        auto const onExit =
+            MakeScopeExit([&, oldVal = self->mIsPerformingDwmFlushHack]() {
+              self->mIsPerformingDwmFlushHack = oldVal;
+            });
+        self->mIsPerformingDwmFlushHack = true;
+
+        MOZ_LOG(gWindowsLog, LogLevel::Debug,
+                ("beginning DWM resize hack for HWND %08" PRIXPTR,
+                 uintptr_t(hwnd)));
+        ::MoveWindow(hwnd, x, y, width, height - 1, FALSE);
+        ::MoveWindow(hwnd, x, y, width, height, TRUE);
+        MOZ_LOG(gWindowsLog, LogLevel::Debug,
+                ("concluded DWM resize hack for HWND %08" PRIXPTR,
+                 uintptr_t(hwnd)));
+      }));
+}
+
+void nsWindow::OnFullscreenChanged(nsSizeMode aOldSizeMode, bool aFullScreen) {
+  MOZ_ASSERT((aOldSizeMode != nsSizeMode_Fullscreen) == aFullScreen);
+
+  // HACK: Potentially flicker-resize the window, to force DWM to get the right
+  // client-area information.
+  if (aFullScreen) {
+    TryDwmResizeHack();
+  }
+
+  // Hide chrome and reposition window. Note this will also cache dimensions for
+  // restoration, so it should only be called once per fullscreen request.
+  //
+  // Don't do this when minimized, since our bounds make no sense then, nor when
+  // coming back from that state.
+  const bool toOrFromMinimized =
+      mFrameState->GetSizeMode() == nsSizeMode_Minimized ||
+      aOldSizeMode == nsSizeMode_Minimized;
+  if (!toOrFromMinimized) {
+    InfallibleMakeFullScreen(aFullScreen);
+  }
+
+  // Possibly notify the taskbar that we have changed our fullscreen mode.
+  TaskbarConcealer::OnFullscreenChanged(this, aFullScreen);
+}
+
+nsresult nsWindow::MakeFullScreen(bool aFullScreen) {
+  mFrameState->EnsureFullscreenMode(aFullScreen);
+  return NS_OK;
+}
+
+/**************************************************************
+ *
+ * SECTION: Native data storage
+ *
+ * nsIWidget::GetNativeData
+ * nsIWidget::FreeNativeData
+ *
+ * Set or clear native data based on a constant.
+ *
+ **************************************************************/
+
+// Return some native data according to aDataType
+void* nsWindow::GetNativeData(uint32_t aDataType) {
+  switch (aDataType) {
+    case NS_NATIVE_WIDGET:
+    case NS_NATIVE_WINDOW:
+    case NS_NATIVE_WINDOW_WEBRTC_DEVICE_ID:
+      return (void*)mWnd;
+    case NS_NATIVE_GRAPHIC:
+      MOZ_ASSERT_UNREACHABLE("Not supported on Windows:");
+      return nullptr;
+    case NS_RAW_NATIVE_IME_CONTEXT: {
+      void* pseudoIMEContext = GetPseudoIMEContext();
+      if (pseudoIMEContext) {
+        return pseudoIMEContext;
+      }
+      [[fallthrough]];
+    }
+    case NS_NATIVE_TSF_THREAD_MGR:
+    case NS_NATIVE_TSF_CATEGORY_MGR:
+    case NS_NATIVE_TSF_DISPLAY_ATTR_MGR:
+      return IMEHandler::GetNativeData(this, aDataType);
+
+    default:
+      break;
+  }
+
+  return nullptr;
+}
+
+// Free some native data according to aDataType
+void nsWindow::FreeNativeData(void* data, uint32_t aDataType) {
+  switch (aDataType) {
+    case NS_NATIVE_GRAPHIC:
+    case NS_NATIVE_WIDGET:
+    case NS_NATIVE_WINDOW:
+      break;
+    default:
+      break;
+  }
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::SetTitle
+ *
+ * Set the main windows title text.
+ *
+ **************************************************************/
+
+nsresult nsWindow::SetTitle(const nsAString& aTitle) {
+  const nsString& strTitle = PromiseFlatString(aTitle);
+  AutoRestore<bool> sendingText(mSendingSetText);
+  mSendingSetText = true;
+  ::SendMessageW(mWnd, WM_SETTEXT, (WPARAM)0, (LPARAM)(LPCWSTR)strTitle.get());
+  return NS_OK;
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::SetIcon
+ *
+ * Set the main windows icon.
+ *
+ **************************************************************/
+
+void nsWindow::SetBigIcon(HICON aIcon) {
+  HICON icon =
+      (HICON)::SendMessageW(mWnd, WM_SETICON, (WPARAM)ICON_BIG, (LPARAM)aIcon);
+  if (icon) {
+    ::DestroyIcon(icon);
+  }
+
+  mIconBig = aIcon;
+}
+
+void nsWindow::SetSmallIcon(HICON aIcon) {
+  HICON icon = (HICON)::SendMessageW(mWnd, WM_SETICON, (WPARAM)ICON_SMALL,
+                                     (LPARAM)aIcon);
+  if (icon) {
+    ::DestroyIcon(icon);
+  }
+
+  mIconSmall = aIcon;
+}
+
+void nsWindow::SetIcon(const nsAString& aIconSpec) {
+  // Assume the given string is a local identifier for an icon file.
+
+  nsCOMPtr<nsIFile> iconFile;
+  ResolveIconName(aIconSpec, u".ico"_ns, getter_AddRefs(iconFile));
+  if (!iconFile) return;
+
+  nsAutoString iconPath;
+  iconFile->GetPath(iconPath);
+
+  // XXX this should use MZLU (see bug 239279)
+
+  ::SetLastError(0);
+
+  HICON bigIcon =
+      (HICON)::LoadImageW(nullptr, (LPCWSTR)iconPath.get(), IMAGE_ICON,
+                          ::GetSystemMetrics(SM_CXICON),
+                          ::GetSystemMetrics(SM_CYICON), LR_LOADFROMFILE);
+  HICON smallIcon =
+      (HICON)::LoadImageW(nullptr, (LPCWSTR)iconPath.get(), IMAGE_ICON,
+                          ::GetSystemMetrics(SM_CXSMICON),
+                          ::GetSystemMetrics(SM_CYSMICON), LR_LOADFROMFILE);
+
+  if (bigIcon) {
+    SetBigIcon(bigIcon);
+  }
+#ifdef DEBUG_SetIcon
+  else {
+    NS_LossyConvertUTF16toASCII cPath(iconPath);
+    MOZ_LOG(gWindowsLog, LogLevel::Info,
+            ("\nIcon load error; icon=%s, rc=0x%08X\n\n", cPath.get(),
+             ::GetLastError()));
+  }
+#endif
+  if (smallIcon) {
+    SetSmallIcon(smallIcon);
+  }
+#ifdef DEBUG_SetIcon
+  else {
+    NS_LossyConvertUTF16toASCII cPath(iconPath);
+    MOZ_LOG(gWindowsLog, LogLevel::Info,
+            ("\nSmall icon load error; icon=%s, rc=0x%08X\n\n", cPath.get(),
+             ::GetLastError()));
+  }
+#endif
+}
+
+void nsWindow::SetBigIconNoData() {
+  HICON bigIcon =
+      ::LoadIconW(::GetModuleHandleW(nullptr), gStockApplicationIcon);
+  SetBigIcon(bigIcon);
+}
+
+void nsWindow::SetSmallIconNoData() {
+  HICON smallIcon =
+      ::LoadIconW(::GetModuleHandleW(nullptr), gStockApplicationIcon);
+  SetSmallIcon(smallIcon);
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::WidgetToScreenOffset
+ *
+ * Return this widget's origin in screen coordinates.
+ *
+ **************************************************************/
+
+LayoutDeviceIntPoint nsWindow::WidgetToScreenOffset() {
+  POINT point;
+  point.x = 0;
+  point.y = 0;
+  ::ClientToScreen(mWnd, &point);
+  return LayoutDeviceIntPoint(point.x, point.y);
+}
+
+LayoutDeviceIntMargin nsWindow::ClientToWindowMargin() {
+  if (mWindowType == WindowType::Popup && !IsPopupWithTitleBar()) {
+    return {};
+  }
+
+  if (mCustomNonClient) {
+    return NonClientSizeMargin(NormalWindowNonClientOffset());
+  }
+
+  // Just use a dummy 200x200 at (200, 200) client rect as the rect.
+  RECT clientRect;
+  clientRect.left = 200;
+  clientRect.top = 200;
+  clientRect.right = 400;
+  clientRect.bottom = 400;
+
+  auto ToRect = [](const RECT& aRect) -> LayoutDeviceIntRect {
+    return {aRect.left, aRect.top, aRect.right - aRect.left,
+            aRect.bottom - aRect.top};
+  };
+
+  RECT windowRect = clientRect;
+  ::AdjustWindowRectEx(&windowRect, WindowStyle(), false, WindowExStyle());
+
+  return ToRect(windowRect) - ToRect(clientRect);
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::EnableDragDrop
+ *
+ * Enables/Disables drag and drop of files on this widget.
+ *
+ **************************************************************/
+
+void nsWindow::EnableDragDrop(bool aEnable) {
+  if (!mWnd) {
+    // Return early if the window already closed
+    return;
+  }
+
+  if (aEnable) {
+    if (!mNativeDragTarget) {
+      mNativeDragTarget = new nsNativeDragTarget(this);
+      mNativeDragTarget->AddRef();
+      ::RegisterDragDrop(mWnd, (LPDROPTARGET)mNativeDragTarget);
+    }
+  } else {
+    if (mWnd && mNativeDragTarget) {
+      ::RevokeDragDrop(mWnd);
+      mNativeDragTarget->DragCancel();
+      NS_RELEASE(mNativeDragTarget);
+    }
+  }
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::CaptureMouse
+ *
+ * Enables/Disables system mouse capture.
+ *
+ **************************************************************/
+
+void nsWindow::CaptureMouse(bool aCapture) {
+  TRACKMOUSEEVENT mTrack;
+  mTrack.cbSize = sizeof(TRACKMOUSEEVENT);
+  mTrack.dwHoverTime = 0;
+  mTrack.hwndTrack = mWnd;
+  if (aCapture) {
+    mTrack.dwFlags = TME_CANCEL | TME_LEAVE;
+    ::SetCapture(mWnd);
+  } else {
+    mTrack.dwFlags = TME_LEAVE;
+    ::ReleaseCapture();
+  }
+  sIsInMouseCapture = aCapture;
+  TrackMouseEvent(&mTrack);
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::CaptureRollupEvents
+ *
+ * Dealing with event rollup on destroy for popups. Enables &
+ * Disables system capture of any and all events that would
+ * cause a dropdown to be rolled up.
+ *
+ **************************************************************/
+
+void nsWindow::CaptureRollupEvents(bool aDoCapture) {
+  if (aDoCapture) {
+    if (!sMsgFilterHook && !sCallProcHook && !sCallMouseHook) {
+      RegisterSpecialDropdownHooks();
+    }
+    sProcessHook = true;
+  } else {
+    sProcessHook = false;
+    UnregisterSpecialDropdownHooks();
+  }
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::GetAttention
+ *
+ * Bring this window to the user's attention.
+ *
+ **************************************************************/
+
+// Draw user's attention to this window until it comes to foreground.
+nsresult nsWindow::GetAttention(int32_t aCycleCount) {
+  // Got window?
+  if (!mWnd) return NS_ERROR_NOT_INITIALIZED;
+
+  HWND flashWnd = WinUtils::GetTopLevelHWND(mWnd, false, false);
+  HWND fgWnd = ::GetForegroundWindow();
+  // Don't flash if the flash count is 0 or if the foreground window is our
+  // window handle or that of our owned-most window.
+  if (aCycleCount == 0 || flashWnd == fgWnd ||
+      flashWnd == WinUtils::GetTopLevelHWND(fgWnd, false, false)) {
+    return NS_OK;
+  }
+
+  DWORD defaultCycleCount = 0;
+  ::SystemParametersInfo(SPI_GETFOREGROUNDFLASHCOUNT, 0, &defaultCycleCount, 0);
+
+  FLASHWINFO flashInfo = {sizeof(FLASHWINFO), flashWnd, FLASHW_ALL,
+                          aCycleCount > 0 ? aCycleCount : defaultCycleCount, 0};
+  ::FlashWindowEx(&flashInfo);
+
+  return NS_OK;
+}
+
+void nsWindow::StopFlashing() {
+  HWND flashWnd = mWnd;
+  while (HWND ownerWnd = ::GetWindow(flashWnd, GW_OWNER)) {
+    flashWnd = ownerWnd;
+  }
+
+  FLASHWINFO flashInfo = {sizeof(FLASHWINFO), flashWnd, FLASHW_STOP, 0, 0};
+  ::FlashWindowEx(&flashInfo);
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::HasPendingInputEvent
+ *
+ * Ask whether there user input events pending.  All input events are
+ * included, including those not targeted at this nsIwidget instance.
+ *
+ **************************************************************/
+
+bool nsWindow::HasPendingInputEvent() {
+  // If there is pending input or the user is currently
+  // moving the window then return true.
+  // Note: When the user is moving the window WIN32 spins
+  // a separate event loop and input events are not
+  // reported to the application.
+  if (HIWORD(GetQueueStatus(QS_INPUT))) return true;
+  GUITHREADINFO guiInfo;
+  guiInfo.cbSize = sizeof(GUITHREADINFO);
+  if (!GetGUIThreadInfo(GetCurrentThreadId(), &guiInfo)) return false;
+  return GUI_INMOVESIZE == (guiInfo.flags & GUI_INMOVESIZE);
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::GetWindowRenderer
+ *
+ * Get the window renderer associated with this widget.
+ *
+ **************************************************************/
+
+WindowRenderer* nsWindow::GetWindowRenderer() {
+  if (mWindowRenderer) {
+    return mWindowRenderer;
+  }
+
+  if (!mLocalesChangedObserver) {
+    mLocalesChangedObserver = new LocalesChangedObserver(this);
+  }
+
+  // Try OMTC first.
+  if (!mWindowRenderer && ShouldUseOffMainThreadCompositing()) {
+    gfxWindowsPlatform::GetPlatform()->UpdateRenderMode();
+    CreateCompositor();
+  }
+
+  if (!mWindowRenderer) {
+    MOZ_ASSERT(!mCompositorSession && !mCompositorBridgeChild);
+    MOZ_ASSERT(!mCompositorWidgetDelegate);
+
+    // Ensure we have a widget proxy even if we're not using the compositor,
+    // since all our transparent window handling lives there.
+    WinCompositorWidgetInitData initData(
+        reinterpret_cast<uintptr_t>(mWnd),
+        reinterpret_cast<uintptr_t>(static_cast<nsIWidget*>(this)),
+        mTransparencyMode, mFrameState->GetSizeMode());
+    // If we're not using the compositor, the options don't actually matter.
+    CompositorOptions options(false, false);
+    mBasicLayersSurface =
+        new InProcessWinCompositorWidget(initData, options, this);
+    mCompositorWidgetDelegate = mBasicLayersSurface;
+    mWindowRenderer = CreateFallbackRenderer();
+  }
+
+  NS_ASSERTION(mWindowRenderer, "Couldn't provide a valid window renderer.");
+
+  if (mWindowRenderer) {
+    // Update the size constraints now that the layer manager has been
+    // created.
+    KnowsCompositor* knowsCompositor = mWindowRenderer->AsKnowsCompositor();
+    if (knowsCompositor) {
+      SizeConstraints c = mSizeConstraints;
+      mMaxTextureSize = knowsCompositor->GetMaxTextureSize();
+      c.mMaxSize.width = std::min(c.mMaxSize.width, mMaxTextureSize);
+      c.mMaxSize.height = std::min(c.mMaxSize.height, mMaxTextureSize);
+      nsBaseWidget::SetSizeConstraints(c);
+    }
+  }
+
+  return mWindowRenderer;
+}
+
+/**************************************************************
+ *
+ * SECTION: nsBaseWidget::SetCompositorWidgetDelegate
+ *
+ * Called to connect the nsWindow to the delegate providing
+ * platform compositing API access.
+ *
+ **************************************************************/
+
+void nsWindow::SetCompositorWidgetDelegate(CompositorWidgetDelegate* delegate) {
+  if (delegate) {
+    mCompositorWidgetDelegate = delegate->AsPlatformSpecificDelegate();
+    MOZ_ASSERT(mCompositorWidgetDelegate,
+               "nsWindow::SetCompositorWidgetDelegate called with a "
+               "non-PlatformCompositorWidgetDelegate");
+  } else {
+    mCompositorWidgetDelegate = nullptr;
+  }
+}
+
+/**************************************************************
+ *
+ * SECTION: nsIWidget::OnDefaultButtonLoaded
+ *
+ * Called after the dialog is loaded and it has a default button.
+ *
+ **************************************************************/
+
+nsresult nsWindow::OnDefaultButtonLoaded(
+    const LayoutDeviceIntRect& aButtonRect) {
+  if (aButtonRect.IsEmpty()) return NS_OK;
+
+  // Don't snap when we are not active.
+  HWND activeWnd = ::GetActiveWindow();
+  if (activeWnd != ::GetForegroundWindow() ||
+      WinUtils::GetTopLevelHWND(mWnd, true) !=
+          WinUtils::GetTopLevelHWND(activeWnd, true)) {
+    return NS_OK;
+  }
+
+  bool isAlwaysSnapCursor =
+      Preferences::GetBool("ui.cursor_snapping.always_enabled", false);
+
+  if (!isAlwaysSnapCursor) {
+    BOOL snapDefaultButton;
+    if (!::SystemParametersInfo(SPI_GETSNAPTODEFBUTTON, 0, &snapDefaultButton,
+                                0) ||
+        !snapDefaultButton)
+      return NS_OK;
+  }
+
+  LayoutDeviceIntRect widgetRect = GetScreenBounds();
+  LayoutDeviceIntRect buttonRect(aButtonRect + widgetRect.TopLeft());
+
+  LayoutDeviceIntPoint centerOfButton(buttonRect.X() + buttonRect.Width() / 2,
+                                      buttonRect.Y() + buttonRect.Height() / 2);
+  // The center of the button can be outside of the widget.
+  // E.g., it could be hidden by scrolling.
+  if (!widgetRect.Contains(centerOfButton)) {
+    return NS_OK;
+  }
+
+  if (!::SetCursorPos(centerOfButton.x, centerOfButton.y)) {
+    NS_ERROR("SetCursorPos failed");
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+uint32_t nsWindow::GetMaxTouchPoints() const {
+  return WinUtils::GetMaxTouchPoints();
+}
+
+void nsWindow::SetWindowClass(const nsAString& xulWinType,
+                              const nsAString& xulWinClass,
+                              const nsAString& xulWinName) {
+  mIsEarlyBlankWindow = xulWinType.EqualsLiteral("navigator:blank");
+}
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: Moz Events
+ **
+ ** Moz GUI event management.
+ **
+ **************************************************************
+ **************************************************************/
+
+/**************************************************************
+ *
+ * SECTION: Mozilla event initialization
+ *
+ * Helpers for initializing moz events.
+ *
+ **************************************************************/
+
+// Event initialization
+void nsWindow::InitEvent(WidgetGUIEvent& event, LayoutDeviceIntPoint* aPoint) {
+  if (nullptr == aPoint) {  // use the point from the event
+    // get the message position in client coordinates
+    if (mWnd != nullptr) {
+      DWORD pos = ::GetMessagePos();
+      POINT cpos;
+
+      cpos.x = GET_X_LPARAM(pos);
+      cpos.y = GET_Y_LPARAM(pos);
+
+      ::ScreenToClient(mWnd, &cpos);
+      event.mRefPoint = LayoutDeviceIntPoint(cpos.x, cpos.y);
+    } else {
+      event.mRefPoint = LayoutDeviceIntPoint(0, 0);
+    }
+  } else {
+    // use the point override if provided
+    event.mRefPoint = *aPoint;
+  }
+
+  event.AssignEventTime(CurrentMessageWidgetEventTime());
+}
+
+WidgetEventTime nsWindow::CurrentMessageWidgetEventTime() const {
+  LONG messageTime = ::GetMessageTime();
+  return WidgetEventTime(GetMessageTimeStamp(messageTime));
+}
+
+/**************************************************************
+ *
+ * SECTION: Moz event dispatch helpers
+ *
+ * Helpers for dispatching different types of moz events.
+ *
+ **************************************************************/
+
+// Main event dispatch. Invokes callback and ProcessEvent method on
+// Event Listener object. Part of nsIWidget.
+nsresult nsWindow::DispatchEvent(WidgetGUIEvent* event,
+                                 nsEventStatus& aStatus) {
+#ifdef WIDGET_DEBUG_OUTPUT
+  debug_DumpEvent(stdout, event->mWidget, event, "something", (int32_t)mWnd);
+#endif  // WIDGET_DEBUG_OUTPUT
+
+  aStatus = nsEventStatus_eIgnore;
+
+  // Top level windows can have a view attached which requires events be sent
+  // to the underlying base window and the view. Added when we combined the
+  // base chrome window with the main content child for nc client area (title
+  // bar) rendering.
+  if (mAttachedWidgetListener) {
+    aStatus = mAttachedWidgetListener->HandleEvent(event, mUseAttachedEvents);
+  } else if (mWidgetListener) {
+    aStatus = mWidgetListener->HandleEvent(event, mUseAttachedEvents);
+  }
+
+  // the window can be destroyed during processing of seemingly innocuous events
+  // like, say, mousedowns due to the magic of scripting. mousedowns will return
+  // nsEventStatus_eIgnore, which causes problems with the deleted window.
+  // therefore:
+  if (mOnDestroyCalled) aStatus = nsEventStatus_eConsumeNoDefault;
+  return NS_OK;
+}
+
+bool nsWindow::DispatchStandardEvent(EventMessage aMsg) {
+  WidgetGUIEvent event(true, aMsg, this);
+  InitEvent(event);
+
+  bool result = DispatchWindowEvent(event);
+  return result;
+}
+
+bool nsWindow::DispatchKeyboardEvent(WidgetKeyboardEvent* event) {
+  nsEventStatus status = DispatchInputEvent(event).mContentStatus;
+  return ConvertStatus(status);
+}
+
+bool nsWindow::DispatchContentCommandEvent(WidgetContentCommandEvent* aEvent) {
+  nsEventStatus status;
+  DispatchEvent(aEvent, status);
+  return ConvertStatus(status);
+}
+
+bool nsWindow::DispatchWheelEvent(WidgetWheelEvent* aEvent) {
+  nsEventStatus status =
+      DispatchInputEvent(aEvent->AsInputEvent()).mContentStatus;
+  return ConvertStatus(status);
+}
+
+// Recursively dispatch synchronous paints for nsIWidget
+// descendants with invalidated rectangles.
+BOOL CALLBACK nsWindow::DispatchStarvedPaints(HWND aWnd, LPARAM aMsg) {
+  LONG_PTR proc = ::GetWindowLongPtrW(aWnd, GWLP_WNDPROC);
+  if (proc == (LONG_PTR)&nsWindow::WindowProc) {
+    // its one of our windows so check to see if it has a
+    // invalidated rect. If it does. Dispatch a synchronous
+    // paint.
+    if (GetUpdateRect(aWnd, nullptr, FALSE)) VERIFY(::UpdateWindow(aWnd));
+  }
+  return TRUE;
+}
+
+// Check for pending paints and dispatch any pending paint
+// messages for any nsIWidget which is a descendant of the
+// top-level window that *this* window is embedded within.
+//
+// Note: We do not dispatch pending paint messages for non
+// nsIWidget managed windows.
+void nsWindow::DispatchPendingEvents() {
+  // We need to ensure that reflow events do not get starved.
+  // At the same time, we don't want to recurse through here
+  // as that would prevent us from dispatching starved paints.
+  static int recursionBlocker = 0;
+  if (recursionBlocker++ == 0) {
+    NS_ProcessPendingEvents(nullptr, PR_MillisecondsToInterval(100));
+    --recursionBlocker;
+  }
+
+  // Quickly check to see if there are any paint events pending,
+  // but only dispatch them if it has been long enough since the
+  // last paint completed.
+  if (::GetQueueStatus(QS_PAINT) &&
+      ((TimeStamp::Now() - mLastPaintEndTime).ToMilliseconds() >= 50)) {
+    // Find the top level window.
+    HWND topWnd = WinUtils::GetTopLevelHWND(mWnd);
+
+    // Dispatch pending paints for topWnd and all its descendant windows.
+    // Note: EnumChildWindows enumerates all descendant windows not just
+    // the children (but not the window itself).
+    nsWindow::DispatchStarvedPaints(topWnd, 0);
+    ::EnumChildWindows(topWnd, nsWindow::DispatchStarvedPaints, 0);
+  }
+}
+
+void nsWindow::DispatchCustomEvent(const nsString& eventName) {
+  if (Document* doc = GetDocument()) {
+    if (nsPIDOMWindowOuter* win = doc->GetWindow()) {
+      win->DispatchCustomEvent(eventName, ChromeOnlyDispatch::eYes);
+    }
+  }
+}
+
+bool nsWindow::TouchEventShouldStartDrag(EventMessage aEventMessage,
+                                         LayoutDeviceIntPoint aEventPoint) {
+  // Allow users to start dragging by double-tapping.
+  if (aEventMessage == eMouseDoubleClick) {
+    return true;
+  }
+
+  // In chrome UI, allow touchdownstartsdrag attributes
+  // to cause any touchdown event to trigger a drag.
+  if (aEventMessage == eMouseDown) {
+    WidgetMouseEvent hittest(true, eMouseHitTest, this,
+                             WidgetMouseEvent::eReal);
+    hittest.mRefPoint = aEventPoint;
+    hittest.mIgnoreRootScrollFrame = true;
+    hittest.mInputSource = MouseEvent_Binding::MOZ_SOURCE_TOUCH;
+    DispatchInputEvent(&hittest);
+
+    if (EventTarget* target = hittest.GetDOMEventTarget()) {
+      if (nsIContent* content = nsIContent::FromEventTarget(target)) {
+        // Check if the element or any parent element has the
+        // attribute we're looking for.
+        for (Element* element = content->GetAsElementOrParentElement(); element;
+             element = element->GetParentElement()) {
+          nsAutoString startDrag;
+          element->GetAttribute(u"touchdownstartsdrag"_ns, startDrag);
+          if (!startDrag.IsEmpty()) {
+            return true;
+          }
+        }
+      }
+    }
+  }
+
+  return false;
+}
+
+// Deal with all sort of mouse event
+bool nsWindow::DispatchMouseEvent(EventMessage aEventMessage, WPARAM wParam,
+                                  LPARAM lParam, bool aIsContextMenuKey,
+                                  int16_t aButton, uint16_t aInputSource,
+                                  WinPointerInfo* aPointerInfo,
+                                  bool aIgnoreAPZ) {
+  ContextMenuPreventer contextMenuPreventer(this);
+  bool result = false;
+
+  UserActivity();
+
+  if (!mWidgetListener) {
+    return result;
+  }
+
+  LayoutDeviceIntPoint eventPoint(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));
+  LayoutDeviceIntPoint mpScreen = eventPoint + WidgetToScreenOffset();
+
+  // Suppress mouse moves caused by widget creation. Make sure to do this early
+  // so that we update sLastMouseMovePoint even for touch-induced mousemove
+  // events.
+  if (aEventMessage == eMouseMove) {
+    if ((sLastMouseMovePoint.x == mpScreen.x.value) &&
+        (sLastMouseMovePoint.y == mpScreen.y.value)) {
+      return result;
+    }
+    sLastMouseMovePoint.x = mpScreen.x;
+    sLastMouseMovePoint.y = mpScreen.y;
+  }
+
+  if (!aIgnoreAPZ && WinUtils::GetIsMouseFromTouch(aEventMessage)) {
+    if (mTouchWindow) {
+      // If mTouchWindow is true, then we must have APZ enabled and be
+      // feeding it raw touch events. In that case we only want to
+      // send touch-generated mouse events to content if they should
+      // start a touch-based drag-and-drop gesture, such as on
+      // double-tapping or when tapping elements marked with the
+      // touchdownstartsdrag attribute in chrome UI.
+      MOZ_ASSERT(mAPZC);
+      if (TouchEventShouldStartDrag(aEventMessage, eventPoint)) {
+        aEventMessage = eMouseTouchDrag;
+      } else {
+        return result;
+      }
+    }
+  }
+
+  uint32_t pointerId =
+      aPointerInfo ? aPointerInfo->pointerId : MOUSE_POINTERID();
+
+  switch (aEventMessage) {
+    case eMouseDown:
+      CaptureMouse(true);
+      break;
+
+    // eMouseMove and eMouseExitFromWidget are here because we need to make
+    // sure capture flag isn't left on after a drag where we wouldn't see a
+    // button up message (see bug 324131).
+    case eMouseUp:
+    case eMouseMove:
+    case eMouseExitFromWidget:
+      if (!(wParam & (MK_LBUTTON | MK_MBUTTON | MK_RBUTTON)) &&
+          sIsInMouseCapture)
+        CaptureMouse(false);
+      break;
+
+    default:
+      break;
+
+  }  // switch
+
+  WidgetMouseEvent event(true, aEventMessage, this, WidgetMouseEvent::eReal,
+                         aIsContextMenuKey ? WidgetMouseEvent::eContextMenuKey
+                                           : WidgetMouseEvent::eNormal);
+  if (aEventMessage == eContextMenu && aIsContextMenuKey) {
+    LayoutDeviceIntPoint zero(0, 0);
+    InitEvent(event, &zero);
+  } else {
+    InitEvent(event, &eventPoint);
+  }
+
+  ModifierKeyState modifierKeyState;
+  modifierKeyState.InitInputEvent(event);
+
+  // eContextMenu with Shift state is special.  It won't fire "contextmenu"
+  // event in the web content for blocking web content to prevent its default.
+  // However, Shift+F10 is a standard shortcut key on Windows.  Therefore,
+  // this should not block web page to prevent its default.  I.e., it should
+  // behave same as ContextMenu key without Shift key.
+  // XXX Should we allow to block web page to prevent its default with
+  //     Ctrl+Shift+F10 or Alt+Shift+F10 instead?
+  if (aEventMessage == eContextMenu && aIsContextMenuKey && event.IsShift() &&
+      NativeKey::LastKeyOrCharMSG().message == WM_SYSKEYDOWN &&
+      NativeKey::LastKeyOrCharMSG().wParam == VK_F10) {
+    event.mModifiers &= ~MODIFIER_SHIFT;
+  }
+
+  event.mButton = aButton;
+  event.mInputSource = aInputSource;
+  if (aPointerInfo) {
+    // Mouse events from Windows WM_POINTER*. Fill more information in
+    // WidgetMouseEvent.
+    event.AssignPointerHelperData(*aPointerInfo);
+    event.mPressure = aPointerInfo->mPressure;
+    event.mButtons = aPointerInfo->mButtons;
+  } else {
+    // If we get here the mouse events must be from non-touch sources, so
+    // convert it to pointer events as well
+    event.convertToPointer = true;
+    event.pointerId = pointerId;
+  }
+
+  // Static variables used to distinguish simple-, double- and triple-clicks.
+  static POINT sLastMousePoint = {0};
+  static LONG sLastMouseDownTime = 0L;
+  static LONG sLastClickCount = 0L;
+  static BYTE sLastMouseButton = 0;
+
+  bool insideMovementThreshold =
+      (DeprecatedAbs(sLastMousePoint.x - eventPoint.x.value) <
+       (short)::GetSystemMetrics(SM_CXDOUBLECLK)) &&
+      (DeprecatedAbs(sLastMousePoint.y - eventPoint.y.value) <
+       (short)::GetSystemMetrics(SM_CYDOUBLECLK));
+
+  BYTE eventButton;
+  switch (aButton) {
+    case MouseButton::ePrimary:
+      eventButton = VK_LBUTTON;
+      break;
+    case MouseButton::eMiddle:
+      eventButton = VK_MBUTTON;
+      break;
+    case MouseButton::eSecondary:
+      eventButton = VK_RBUTTON;
+      break;
+    default:
+      eventButton = 0;
+      break;
+  }
+
+  // Doubleclicks are used to set the click count, then changed to mousedowns
+  // We're going to time double-clicks from mouse *up* to next mouse *down*
+  LONG curMsgTime = ::GetMessageTime();
+
+  switch (aEventMessage) {
+    case eMouseDoubleClick:
+      event.mMessage = eMouseDown;
+      event.mButton = aButton;
+      sLastClickCount = 2;
+      sLastMouseDownTime = curMsgTime;
+      break;
+    case eMouseUp:
+      // remember when this happened for the next mouse down
+      sLastMousePoint.x = eventPoint.x;
+      sLastMousePoint.y = eventPoint.y;
+      sLastMouseButton = eventButton;
+      break;
+    case eMouseDown:
+      // now look to see if we want to convert this to a double- or triple-click
+      if (((curMsgTime - sLastMouseDownTime) < (LONG)::GetDoubleClickTime()) &&
+          insideMovementThreshold && eventButton == sLastMouseButton) {
+        sLastClickCount++;
+      } else {
+        // reset the click count, to count *this* click
+        sLastClickCount = 1;
+      }
+      // Set last Click time on MouseDown only
+      sLastMouseDownTime = curMsgTime;
+      break;
+    case eMouseMove:
+      if (!insideMovementThreshold) {
+        sLastClickCount = 0;
+      }
+      break;
+    case eMouseExitFromWidget:
+      event.mExitFrom =
+          Some(IsTopLevelMouseExit(mWnd) ? WidgetMouseEvent::ePlatformTopLevel
+                                         : WidgetMouseEvent::ePlatformChild);
+      break;
+    default:
+      break;
+  }
+  event.mClickCount = sLastClickCount;
+
+#ifdef NS_DEBUG_XX
+  MOZ_LOG(gWindowsLog, LogLevel::Info,
+          ("Msg Time: %d Click Count: %d\n", curMsgTime, event.mClickCount));
+#endif
+
+  // call the event callback
+  if (mWidgetListener) {
+    if (aEventMessage == eMouseMove) {
+      LayoutDeviceIntRect rect = GetBounds();
+      rect.MoveTo(0, 0);
+
+      if (rect.Contains(event.mRefPoint)) {
+        if (sCurrentWindow == nullptr || sCurrentWindow != this) {
+          if ((nullptr != sCurrentWindow) && (!sCurrentWindow->mInDtor)) {
+            LPARAM pos = sCurrentWindow->lParamToClient(lParamToScreen(lParam));
+            sCurrentWindow->DispatchMouseEvent(
+                eMouseExitFromWidget, wParam, pos, false, MouseButton::ePrimary,
+                aInputSource, aPointerInfo);
+          }
+          sCurrentWindow = this;
+          if (!mInDtor) {
+            LPARAM pos = sCurrentWindow->lParamToClient(lParamToScreen(lParam));
+            sCurrentWindow->DispatchMouseEvent(
+                eMouseEnterIntoWidget, wParam, pos, false,
+                MouseButton::ePrimary, aInputSource, aPointerInfo);
+          }
+        }
+      }
+    } else if (aEventMessage == eMouseExitFromWidget) {
+      if (sCurrentWindow == this) {
+        sCurrentWindow = nullptr;
+      }
+    }
+
+    nsIWidget::ContentAndAPZEventStatus eventStatus =
+        DispatchInputEvent(&event);
+    contextMenuPreventer.Update(event, eventStatus);
+    return ConvertStatus(eventStatus.mContentStatus);
+  }
+
+  return result;
+}
+
+HWND nsWindow::GetTopLevelForFocus(HWND aCurWnd) {
+  // retrieve the toplevel window or dialogue
+  HWND toplevelWnd = nullptr;
+  while (aCurWnd) {
+    toplevelWnd = aCurWnd;
+    nsWindow* win = WinUtils::GetNSWindowPtr(aCurWnd);
+    if (win) {
+      if (win->mWindowType == WindowType::TopLevel ||
+          win->mWindowType == WindowType::Dialog) {
+        break;
+      }
+    }
+
+    aCurWnd = ::GetParent(aCurWnd);  // Parent or owner (if has no parent)
+  }
+  return toplevelWnd;
+}
+
+void nsWindow::DispatchFocusToTopLevelWindow(bool aIsActivate) {
+  if (aIsActivate) {
+    sJustGotActivate = false;
+  }
+  sJustGotDeactivate = false;
+  mLastKillFocusWindow = nullptr;
+
+  HWND toplevelWnd = GetTopLevelForFocus(mWnd);
+
+  if (toplevelWnd) {
+    nsWindow* win = WinUtils::GetNSWindowPtr(toplevelWnd);
+    if (win && win->mWidgetListener) {
+      if (aIsActivate) {
+        win->mWidgetListener->WindowActivated();
+      } else {
+        win->mWidgetListener->WindowDeactivated();
+      }
+    }
+  }
+}
+
+HWND nsWindow::WindowAtMouse() {
+  DWORD pos = ::GetMessagePos();
+  POINT mp;
+  mp.x = GET_X_LPARAM(pos);
+  mp.y = GET_Y_LPARAM(pos);
+  return ::WindowFromPoint(mp);
+}
+
+bool nsWindow::IsTopLevelMouseExit(HWND aWnd) {
+  HWND mouseWnd = WindowAtMouse();
+
+  // WinUtils::GetTopLevelHWND() will return a HWND for the window frame
+  // (which includes the non-client area).  If the mouse has moved into
+  // the non-client area, we should treat it as a top-level exit.
+  HWND mouseTopLevel = WinUtils::GetTopLevelHWND(mouseWnd);
+  if (mouseWnd == mouseTopLevel) return true;
+
+  return WinUtils::GetTopLevelHWND(aWnd) != mouseTopLevel;
+}
+
+/**************************************************************
+ *
+ * SECTION: IPC
+ *
+ * IPC related helpers.
+ *
+ **************************************************************/
+
+// static
+bool nsWindow::IsAsyncResponseEvent(UINT aMsg, LRESULT& aResult) {
+  switch (aMsg) {
+    case WM_SETFOCUS:
+    case WM_KILLFOCUS:
+    case WM_ENABLE:
+    case WM_WINDOWPOSCHANGING:
+    case WM_WINDOWPOSCHANGED:
+    case WM_PARENTNOTIFY:
+    case WM_ACTIVATEAPP:
+    case WM_NCACTIVATE:
+    case WM_ACTIVATE:
+    case WM_CHILDACTIVATE:
+    case WM_IME_SETCONTEXT:
+    case WM_IME_NOTIFY:
+    case WM_SHOWWINDOW:
+    case WM_CANCELMODE:
+    case WM_MOUSEACTIVATE:
+    case WM_CONTEXTMENU:
+      aResult = 0;
+      return true;
+
+    case WM_SETTINGCHANGE:
+    case WM_SETCURSOR:
+      return false;
+  }
+
+#ifdef DEBUG
+  char szBuf[200];
+  sprintf(szBuf,
+          "An unhandled ISMEX_SEND message was received during spin loop! (%X)",
+          aMsg);
+  NS_WARNING(szBuf);
+#endif
+
+  return false;
+}
+
+void nsWindow::IPCWindowProcHandler(UINT& msg, WPARAM& wParam, LPARAM& lParam) {
+  MOZ_ASSERT_IF(
+      msg != WM_GETOBJECT,
+      !mozilla::ipc::MessageChannel::IsPumpingMessages() ||
+          mozilla::ipc::SuppressedNeuteringRegion::IsNeuteringSuppressed());
+
+  // Modal UI being displayed in windowless plugins.
+  if (mozilla::ipc::MessageChannel::IsSpinLoopActive() &&
+      (InSendMessageEx(nullptr) & (ISMEX_REPLIED | ISMEX_SEND)) == ISMEX_SEND) {
+    LRESULT res;
+    if (IsAsyncResponseEvent(msg, res)) {
+      ReplyMessage(res);
+    }
+    return;
+  }
+
+  // Handle certain sync plugin events sent to the parent which
+  // trigger ipc calls that result in deadlocks.
+
+  DWORD dwResult = 0;
+  bool handled = false;
+
+  switch (msg) {
+    // Windowless flash sending WM_ACTIVATE events to the main window
+    // via calls to ShowWindow.
+    case WM_ACTIVATE:
+      if (lParam != 0 && LOWORD(wParam) == WA_ACTIVE &&
+          IsWindow((HWND)lParam)) {
+        // Check for Adobe Reader X sync activate message from their
+        // helper window and ignore. Fixes an annoying focus problem.
+        if ((InSendMessageEx(nullptr) & (ISMEX_REPLIED | ISMEX_SEND)) ==
+            ISMEX_SEND) {
+          wchar_t szClass[10];
+          HWND focusWnd = (HWND)lParam;
+          if (IsWindowVisible(focusWnd) &&
+              GetClassNameW(focusWnd, szClass,
+                            sizeof(szClass) / sizeof(char16_t)) &&
+              !wcscmp(szClass, L"Edit") &&
+              !WinUtils::IsOurProcessWindow(focusWnd)) {
+            break;
+          }
+        }
+        handled = true;
+      }
+      break;
+    // Plugins taking or losing focus triggering focus app messages.
+    case WM_SETFOCUS:
+    case WM_KILLFOCUS:
+    // Windowed plugins that pass sys key events to defwndproc generate
+    // WM_SYSCOMMAND events to the main window.
+    case WM_SYSCOMMAND:
+    // Windowed plugins that fire context menu selection events to parent
+    // windows.
+    case WM_CONTEXTMENU:
+    // IME events fired as a result of synchronous focus changes
+    case WM_IME_SETCONTEXT:
+      handled = true;
+      break;
+  }
+
+  if (handled &&
+      (InSendMessageEx(nullptr) & (ISMEX_REPLIED | ISMEX_SEND)) == ISMEX_SEND) {
+    ReplyMessage(dwResult);
+  }
+}
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: Native events
+ **
+ ** Main Windows message handlers and OnXXX handlers for
+ ** Windows event handling.
+ **
+ **************************************************************
+ **************************************************************/
+
+/**************************************************************
+ *
+ * SECTION: Wind proc.
+ *
+ * The main Windows event procedures and associated
+ * message processing methods.
+ *
+ **************************************************************/
+
+static bool DisplaySystemMenu(HWND hWnd, nsSizeMode sizeMode, bool isRtl,
+                              int32_t x, int32_t y) {
+  HMENU hMenu = GetSystemMenu(hWnd, FALSE);
+  if (hMenu) {
+    MENUITEMINFO mii;
+    mii.cbSize = sizeof(MENUITEMINFO);
+    mii.fMask = MIIM_STATE;
+    mii.fType = 0;
+
+    // update the options
+    mii.fState = MF_ENABLED;
+    SetMenuItemInfo(hMenu, SC_RESTORE, FALSE, &mii);
+    SetMenuItemInfo(hMenu, SC_SIZE, FALSE, &mii);
+    SetMenuItemInfo(hMenu, SC_MOVE, FALSE, &mii);
+    SetMenuItemInfo(hMenu, SC_MAXIMIZE, FALSE, &mii);
+    SetMenuItemInfo(hMenu, SC_MINIMIZE, FALSE, &mii);
+
+    mii.fState = MF_GRAYED;
+    switch (sizeMode) {
+      case nsSizeMode_Fullscreen:
+        // intentional fall through
+      case nsSizeMode_Maximized:
+        SetMenuItemInfo(hMenu, SC_SIZE, FALSE, &mii);
+        SetMenuItemInfo(hMenu, SC_MOVE, FALSE, &mii);
+        SetMenuItemInfo(hMenu, SC_MAXIMIZE, FALSE, &mii);
+        break;
+      case nsSizeMode_Minimized:
+        SetMenuItemInfo(hMenu, SC_MINIMIZE, FALSE, &mii);
+        break;
+      case nsSizeMode_Normal:
+        SetMenuItemInfo(hMenu, SC_RESTORE, FALSE, &mii);
+        break;
+      case nsSizeMode_Invalid:
+        NS_ASSERTION(false, "Did the argument come from invalid IPC?");
+        break;
+      default:
+        MOZ_ASSERT_UNREACHABLE("Unhnalded nsSizeMode value detected");
+        break;
+    }
+    LPARAM cmd = TrackPopupMenu(
+        hMenu,
+        (TPM_LEFTBUTTON | TPM_RIGHTBUTTON | TPM_RETURNCMD | TPM_TOPALIGN |
+         (isRtl ? TPM_RIGHTALIGN : TPM_LEFTALIGN)),
+        x, y, 0, hWnd, nullptr);
+    if (cmd) {
+      PostMessage(hWnd, WM_SYSCOMMAND, cmd, 0);
+      return true;
+    }
+  }
+  return false;
+}
+
+// The WndProc procedure for all nsWindows in this toolkit. This merely catches
+// SEH exceptions and passes the real work to WindowProcInternal. See bug 587406
+// and http://msdn.microsoft.com/en-us/library/ms633573%28VS.85%29.aspx
+LRESULT CALLBACK nsWindow::WindowProc(HWND hWnd, UINT msg, WPARAM wParam,
+                                      LPARAM lParam) {
+  mozilla::ipc::CancelCPOWs();
+
+  BackgroundHangMonitor().NotifyActivity();
+
+  return mozilla::CallWindowProcCrashProtected(WindowProcInternal, hWnd, msg,
+                                               wParam, lParam);
+}
+
+LRESULT CALLBACK nsWindow::WindowProcInternal(HWND hWnd, UINT msg,
+                                              WPARAM wParam, LPARAM lParam) {
+  if (::GetWindowLongPtrW(hWnd, GWLP_ID) == eFakeTrackPointScrollableID) {
+    // This message was sent to the FAKETRACKPOINTSCROLLABLE.
+    if (msg == WM_HSCROLL) {
+      // Route WM_HSCROLL messages to the main window.
+      hWnd = ::GetParent(::GetParent(hWnd));
+    } else {
+      // Handle all other messages with its original window procedure.
+      WNDPROC prevWindowProc = (WNDPROC)::GetWindowLongPtr(hWnd, GWLP_USERDATA);
+      return ::CallWindowProcW(prevWindowProc, hWnd, msg, wParam, lParam);
+    }
+  }
+
+  if (msg == MOZ_WM_TRACE) {
+    // This is a tracer event for measuring event loop latency.
+    // See WidgetTraceEvent.cpp for more details.
+    mozilla::SignalTracerThread();
+    return 0;
+  }
+
+  // Get the window which caused the event and ask it to process the message
+  nsWindow* targetWindow = WinUtils::GetNSWindowPtr(hWnd);
+  NS_ASSERTION(targetWindow, "nsWindow* is null!");
+  if (!targetWindow) return ::DefWindowProcW(hWnd, msg, wParam, lParam);
+
+  // Hold the window for the life of this method, in case it gets
+  // destroyed during processing, unless we're in the dtor already.
+  nsCOMPtr<nsIWidget> kungFuDeathGrip;
+  if (!targetWindow->mInDtor) kungFuDeathGrip = targetWindow;
+
+  targetWindow->IPCWindowProcHandler(msg, wParam, lParam);
+
+  // Create this here so that we store the last rolled up popup until after
+  // the event has been processed.
+  nsAutoRollup autoRollup;
+
+  LRESULT popupHandlingResult;
+  if (DealWithPopups(hWnd, msg, wParam, lParam, &popupHandlingResult))
+    return popupHandlingResult;
+
+  // Call ProcessMessage
+  LRESULT retValue;
+  if (targetWindow->ProcessMessage(msg, wParam, lParam, &retValue)) {
+    return retValue;
+  }
+
+  LRESULT res = ::CallWindowProcW(targetWindow->GetPrevWindowProc(), hWnd, msg,
+                                  wParam, lParam);
+
+  return res;
+}
+
+const char16_t* GetQuitType() {
+  if (Preferences::GetBool(PREF_WIN_REGISTER_APPLICATION_RESTART, false)) {
+    DWORD cchCmdLine = 0;
+    HRESULT rc = ::GetApplicationRestartSettings(::GetCurrentProcess(), nullptr,
+                                                 &cchCmdLine, nullptr);
+    if (rc == S_OK) {
+      return u"os-restart";
+    }
+  }
+  return nullptr;
+}
+
+bool nsWindow::ExternalHandlerProcessMessage(UINT aMessage, WPARAM& aWParam,
+                                             LPARAM& aLParam,
+                                             MSGResult& aResult) {
+  if (mWindowHook.Notify(mWnd, aMessage, aWParam, aLParam, aResult)) {
+    return true;
+  }
+
+  if (IMEHandler::ProcessMessage(this, aMessage, aWParam, aLParam, aResult)) {
+    return true;
+  }
+
+  if (MouseScrollHandler::ProcessMessage(this, aMessage, aWParam, aLParam,
+                                         aResult)) {
+    return true;
+  }
+
+  return false;
+}
+
+// The main windows message processing method. Wraps ProcessMessageInternal so
+// we can log aRetValue.
+bool nsWindow::ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
+                              LRESULT* aRetValue) {
+  // For some events we might change the parameter values, so log
+  // before and after we process them.
+  NativeEventLogger eventLogger("nsWindow", mWnd, msg, wParam, lParam);
+  bool result = ProcessMessageInternal(msg, wParam, lParam, aRetValue);
+  eventLogger.SetResult(*aRetValue, result);
+
+  return result;
+}
+
+// The main windows message processing method. Called by ProcessMessage.
+bool nsWindow::ProcessMessageInternal(UINT msg, WPARAM& wParam, LPARAM& lParam,
+                                      LRESULT* aRetValue) {
+  MSGResult msgResult(aRetValue);
+  if (ExternalHandlerProcessMessage(msg, wParam, lParam, msgResult)) {
+    return (msgResult.mConsumed || !mWnd);
+  }
+
+  bool result = false;  // call the default nsWindow proc
+  *aRetValue = 0;
+
+  // The DWM resize hack (see bug 1763981) causes us to process a number of
+  // messages, notably including some WM_WINDOWPOSCHANG{ING,ED} messages which
+  // would ordinarily result in a whole lot of internal state being updated.
+  //
+  // Since we're supposed to end in the same state we started in (and since the
+  // content shouldn't know about any of this nonsense), just discard any
+  // messages synchronously dispatched from within the hack.
+  if (MOZ_UNLIKELY(mIsPerformingDwmFlushHack)) {
+    return true;
+  }
+
+  // Glass hit testing w/custom transparent margins.
+  //
+  // FIXME(emilio): is this needed? We deal with titlebar buttons non-natively
+  // now.
+  LRESULT dwmHitResult;
+  if (mCustomNonClient &&
+      DwmDefWindowProc(mWnd, msg, wParam, lParam, &dwmHitResult)) {
+    *aRetValue = dwmHitResult;
+    return true;
+  }
+
+  // The preference whether to use a different keyboard layout for each
+  // window is cached, and updating it will not take effect until the
+  // next restart. We read the preference here and not upon WM_ACTIVATE to make
+  // sure that this behavior is consistent. Otherwise, if the user changed the
+  // preference before having ever lowered the window, the preference would take
+  // effect immediately.
+  static const bool sSwitchKeyboardLayout =
+      Preferences::GetBool("intl.keyboard.per_window_layout", false);
+  AppShutdownReason shutdownReason = AppShutdownReason::Unknown;
+
+  // (Large blocks of code should be broken out into OnEvent handlers.)
+  switch (msg) {
+    // WM_QUERYENDSESSION must be handled by all windows.
+    // Otherwise Windows thinks the window can just be killed at will.
+    case WM_QUERYENDSESSION: {
+      // Ask around if it's ok to quit.
+      nsCOMPtr<nsIObserverService> obsServ =
+          mozilla::services::GetObserverService();
+      nsCOMPtr<nsISupportsPRBool> cancelQuitWrapper =
+          do_CreateInstance(NS_SUPPORTS_PRBOOL_CONTRACTID);
+      cancelQuitWrapper->SetData(false);
+
+      const char16_t* quitType = GetQuitType();
+      obsServ->NotifyObservers(cancelQuitWrapper, "quit-application-requested",
+                               quitType);
+
+      bool shouldCancelQuit;
+      cancelQuitWrapper->GetData(&shouldCancelQuit);
+      *aRetValue = !shouldCancelQuit;
+      result = true;
+    } break;
+
+    case MOZ_WM_STARTA11Y:
+#if defined(ACCESSIBILITY)
+      Unused << GetAccessible();
+      result = true;
+#else
+      result = false;
+#endif
+      break;
+
+    case WM_ENDSESSION: {
+      // For WM_ENDSESSION, wParam indicates whether we need to shutdown
+      // (TRUE) or not (FALSE).
+      if (!wParam) {
+        result = true;
+        break;
+      }
+      // According to WM_ENDSESSION lParam documentation:
+      //   0 -> OS shutdown or restart (no way to distinguish)
+      //   ENDSESSION_LOGOFF -> User is logging off
+      //   ENDSESSION_CLOSEAPP -> Application must shutdown
+      //   ENDSESSION_CRITICAL -> Application is forced to shutdown
+      // The difference of the last two is not very clear.
+      if (lParam == 0) {
+        shutdownReason = AppShutdownReason::OSShutdown;
+      } else if (lParam & ENDSESSION_LOGOFF) {
+        shutdownReason = AppShutdownReason::OSSessionEnd;
+      } else if (lParam & (ENDSESSION_CLOSEAPP | ENDSESSION_CRITICAL)) {
+        shutdownReason = AppShutdownReason::OSForceClose;
+      } else {
+        MOZ_DIAGNOSTIC_ASSERT(false,
+                              "Received WM_ENDSESSION with unknown flags.");
+        shutdownReason = AppShutdownReason::OSForceClose;
+      }
+    }
+      [[fallthrough]];
+    case MOZ_WM_APP_QUIT: {
+      if (shutdownReason == AppShutdownReason::Unknown) {
+        // TODO: We do not expect that these days anybody sends us
+        // MOZ_WM_APP_QUIT, see bug 1827807.
+        shutdownReason = AppShutdownReason::WinUnexpectedMozQuit;
+      }
+      // Let's fake a shutdown sequence without actually closing windows etc.
+      // to avoid Windows killing us in the middle. A proper shutdown would
+      // require having a chance to pump some messages. Unfortunately
+      // Windows won't let us do that. Bug 212316.
+      nsCOMPtr<nsIObserverService> obsServ =
+          mozilla::services::GetObserverService();
+      const char16_t* syncShutdown = u"syncShutdown";
+      const char16_t* quitType = GetQuitType();
+
+      AppShutdown::Init(AppShutdownMode::Normal, 0, shutdownReason);
+
+      obsServ->NotifyObservers(nullptr, "quit-application-granted",
+                               syncShutdown);
+      obsServ->NotifyObservers(nullptr, "quit-application-forced", nullptr);
+
+      AppShutdown::OnShutdownConfirmed();
+
+      AppShutdown::AdvanceShutdownPhase(ShutdownPhase::AppShutdownConfirmed,
+                                        quitType);
+      AppShutdown::AdvanceShutdownPhase(ShutdownPhase::AppShutdownNetTeardown,
+                                        nullptr);
+      AppShutdown::AdvanceShutdownPhase(ShutdownPhase::AppShutdownTeardown,
+                                        nullptr);
+      AppShutdown::AdvanceShutdownPhase(ShutdownPhase::AppShutdown, nullptr);
+      AppShutdown::AdvanceShutdownPhase(ShutdownPhase::AppShutdownQM, nullptr);
+      AppShutdown::AdvanceShutdownPhase(ShutdownPhase::AppShutdownTelemetry,
+                                        nullptr);
+
+      AppShutdown::DoImmediateExit();
+      MOZ_ASSERT_UNREACHABLE("Our process was supposed to exit.");
+    } break;
+
+    case WM_SYSCOLORCHANGE:
+      // No need to invalidate layout for system color changes, but we need to
+      // invalidate style.
+      NotifyThemeChanged(widget::ThemeChangeKind::Style);
+      break;
+
+    case WM_THEMECHANGED: {
+      // Update non-client margin offsets
+      UpdateNonClientMargins();
+      nsUXThemeData::UpdateNativeThemeInfo();
+
+      // We assume pretty much everything could've changed here.
+      NotifyThemeChanged(widget::ThemeChangeKind::StyleAndLayout);
+
+      UpdateDarkModeToolbar();
+
+      // Invalidate the window so that the repaint will
+      // pick up the new theme.
+      Invalidate(true, true, true);
+    } break;
+
+    case WM_WTSSESSION_CHANGE: {
+      switch (wParam) {
+        case WTS_CONSOLE_CONNECT:
+        case WTS_REMOTE_CONNECT:
+        case WTS_SESSION_UNLOCK:
+          // When a session becomes visible, we should invalidate.
+          Invalidate(true, true, true);
+          break;
+        default:
+          break;
+      }
+    } break;
+
+    case WM_FONTCHANGE: {
+      // We only handle this message for the hidden window,
+      // as we only need to update the (global) font list once
+      // for any given change, not once per window!
+      if (mWindowType != WindowType::Invisible) {
+        break;
+      }
+
+      // update the global font list
+      gfxPlatform::GetPlatform()->UpdateFontList();
+    } break;
+
+    case WM_SETTINGCHANGE: {
+      if (wParam == SPI_SETCLIENTAREAANIMATION ||
+          wParam == SPI_SETKEYBOARDDELAY || wParam == SPI_SETMOUSEVANISH) {
+        // These need to update LookAndFeel cached values.
+        // They affect reduced motion settings / caret blink count / show
+        // pointer while typing, so no need to invalidate style / layout.
+        NotifyThemeChanged(widget::ThemeChangeKind::MediaQueriesOnly);
+        break;
+      }
+      if (wParam == SPI_SETFONTSMOOTHING ||
+          wParam == SPI_SETFONTSMOOTHINGTYPE) {
+        gfxDWriteFont::UpdateSystemTextVars();
+        break;
+      }
+      if (wParam == SPI_SETWORKAREA) {
+        // NB: We also refresh screens on WM_DISPLAYCHANGE but the rcWork
+        // values are sometimes wrong at that point.  This message then
+        // arrives soon afterward, when we can get the right rcWork values.
+        ScreenHelperWin::RefreshScreens();
+        break;
+      }
+      if (auto lParamString = reinterpret_cast<const wchar_t*>(lParam)) {
+        if (!wcscmp(lParamString, L"ImmersiveColorSet")) {
+          // This affects system colors (-moz-win-accentcolor), so gotta pass
+          // the style flag.
+          NotifyThemeChanged(widget::ThemeChangeKind::Style);
+          break;
+        }
+
+        // UserInteractionMode, ConvertibleSlateMode, SystemDockMode may cause
+        // @media(pointer) queries to change, which layout needs to know about
+        //
+        // (WM_SETTINGCHANGE will be sent to all top-level windows, so we
+        //  only respond to the hidden top-level window to avoid hammering
+        //  layout with a bunch of NotifyThemeChanged() calls)
+        //
+        if (mWindowType == WindowType::Invisible) {
+          if (!wcscmp(lParamString, L"UserInteractionMode") ||
+              !wcscmp(lParamString, L"ConvertibleSlateMode") ||
+              !wcscmp(lParamString, L"SystemDockMode")) {
+            NotifyThemeChanged(widget::ThemeChangeKind::MediaQueriesOnly);
+            WindowsUIUtils::UpdateInTabletMode();
+          }
+        }
+      }
+    } break;
+
+    case WM_DEVICECHANGE: {
+      if (wParam == DBT_DEVICEARRIVAL || wParam == DBT_DEVICEREMOVECOMPLETE) {
+        DEV_BROADCAST_HDR* hdr = reinterpret_cast<DEV_BROADCAST_HDR*>(lParam);
+        // Check dbch_devicetype explicitly since we will get other device types
+        // (e.g. DBT_DEVTYP_VOLUME) for some reasons even if we specify
+        // DBT_DEVTYP_DEVICEINTERFACE in the filter for
+        // RegisterDeviceNotification.
+        if (hdr->dbch_devicetype == DBT_DEVTYP_DEVICEINTERFACE) {
+          // This can only change media queries (any-hover/any-pointer).
+          NotifyThemeChanged(widget::ThemeChangeKind::MediaQueriesOnly);
+        }
+      }
+    } break;
+
+    case WM_NCCALCSIZE: {
+      // NOTE: the following block is mirrored in PreXULSkeletonUI.cpp, and
+      // will need to be kept in sync.
+      if (mCustomNonClient) {
+        // If `wParam` is `FALSE`, `lParam` points to a `RECT` that contains
+        // the proposed window rectangle for our window.  During our
+        // processing of the `WM_NCCALCSIZE` message, we are expected to
+        // modify the `RECT` that `lParam` points to, so that its value upon
+        // our return is the new client area.  We must return 0 if `wParam`
+        // is `FALSE`.
+        //
+        // If `wParam` is `TRUE`, `lParam` points to a `NCCALCSIZE_PARAMS`
+        // struct.  This struct contains an array of 3 `RECT`s, the first of
+        // which has the exact same meaning as the `RECT` that is pointed to
+        // by `lParam` when `wParam` is `FALSE`.  The remaining `RECT`s, in
+        // conjunction with our return value, can
+        // be used to specify portions of the source and destination window
+        // rectangles that are valid and should be preserved.  We opt not to
+        // implement an elaborate client-area preservation technique, and
+        // simply return 0, which means "preserve the entire old client area
+        // and align it with the upper-left corner of our new client area".
+        RECT* clientRect =
+            wParam ? &(reinterpret_cast<NCCALCSIZE_PARAMS*>(lParam))->rgrc[0]
+                   : (reinterpret_cast<RECT*>(lParam));
+        auto margin = NonClientSizeMargin();
+        clientRect->top += margin.top;
+        clientRect->left += margin.left;
+        clientRect->right -= margin.right;
+        clientRect->bottom -= margin.bottom;
+        // Make client rect's width and height more than 0 to
+        // avoid problems of webrender and angle.
+        clientRect->right = std::max(clientRect->right, clientRect->left + 1);
+        clientRect->bottom = std::max(clientRect->bottom, clientRect->top + 1);
+
+        result = true;
+        *aRetValue = 0;
+      }
+      break;
+    }
+
+    case WM_NCHITTEST: {
+      if (mInputRegion.mFullyTransparent) {
+        // Treat this window as transparent.
+        *aRetValue = HTTRANSPARENT;
+        result = true;
+        break;
+      }
+
+      if (mInputRegion.mMargin) {
+        const LayoutDeviceIntPoint screenPoint(GET_X_LPARAM(lParam),
+                                               GET_Y_LPARAM(lParam));
+        LayoutDeviceIntRect screenRect = GetScreenBounds();
+        screenRect.Deflate(mInputRegion.mMargin);
+        if (!screenRect.Contains(screenPoint)) {
+          *aRetValue = HTTRANSPARENT;
+          result = true;
+          break;
+        }
+      }
+
+      /*
+       * If an nc client area margin has been moved, we are responsible
+       * for calculating where the resize margins are and returning the
+       * appropriate set of hit test constants. DwmDefWindowProc (above)
+       * will handle hit testing on it's command buttons if we are on a
+       * composited desktop.
+       */
+
+      if (!mCustomNonClient) {
+        break;
+      }
+
+      *aRetValue =
+          ClientMarginHitTestPoint(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));
+      result = true;
+      break;
+    }
+
+    case WM_SETTEXT:
+      /*
+       * WM_SETTEXT paints the titlebar area. Avoid this if we have a
+       * custom titlebar we paint ourselves, or if we're the ones
+       * sending the message with an updated title
+       */
+
+      if (mSendingSetText || !mCustomNonClient || mNonClientMargins.top == -1)
+        break;
+
+      {
+        // From msdn, the way around this is to disable the visible state
+        // temporarily. We need the text to be set but we don't want the
+        // redraw to occur. However, we need to make sure that we don't
+        // do this at the same time that a Present is happening.
+        //
+        // To do this we take mPresentLock in nsWindow::PreRender and
+        // if that lock is taken we wait before doing WM_SETTEXT
+        if (mCompositorWidgetDelegate) {
+          mCompositorWidgetDelegate->EnterPresentLock();
+        }
+        DWORD style = GetWindowLong(mWnd, GWL_STYLE);
+        SetWindowLong(mWnd, GWL_STYLE, style & ~WS_VISIBLE);
+        *aRetValue =
+            CallWindowProcW(GetPrevWindowProc(), mWnd, msg, wParam, lParam);
+        SetWindowLong(mWnd, GWL_STYLE, style);
+        if (mCompositorWidgetDelegate) {
+          mCompositorWidgetDelegate->LeavePresentLock();
+        }
+
+        return true;
+      }
+
+    case WM_NCACTIVATE: {
+      /*
+       * WM_NCACTIVATE paints nc areas. Avoid this and re-route painting
+       * through WM_NCPAINT via InvalidateNonClientRegion.
+       */
+      UpdateGetWindowInfoCaptionStatus(FALSE != wParam);
+
+      if (!mCustomNonClient) {
+        break;
+      }
+
+      // There is a case that rendered result is not kept. Bug 1237617
+      if (wParam == TRUE && !gfxEnv::MOZ_DISABLE_FORCE_PRESENT()) {
+        NS_DispatchToMainThread(NewRunnableMethod(
+            "nsWindow::ForcePresent", this, &nsWindow::ForcePresent));
+      }
+
+      // let the dwm handle nc painting on glass
+      // Never allow native painting if we are on fullscreen
+      if (mFrameState->GetSizeMode() != nsSizeMode_Fullscreen) break;
+
+      if (wParam == TRUE) {
+        // going active
+        *aRetValue = FALSE;  // ignored
+        result = true;
+        // invalidate to trigger a paint
+        InvalidateNonClientRegion();
+        break;
+      } else {
+        // going inactive
+        *aRetValue = TRUE;  // go ahead and deactive
+        result = true;
+        // invalidate to trigger a paint
+        InvalidateNonClientRegion();
+        break;
+      }
+    }
+
+    case WM_NCPAINT: {
+      /*
+       * ClearType changes often don't send a WM_SETTINGCHANGE message. But they
+       * do seem to always send a WM_NCPAINT message, so let's update on that.
+       */
+      gfxDWriteFont::UpdateSystemTextVars();
+    } break;
+
+    case WM_POWERBROADCAST:
+      switch (wParam) {
+        case PBT_APMSUSPEND:
+          PostSleepWakeNotification(true);
+          break;
+        case PBT_APMRESUMEAUTOMATIC:
+        case PBT_APMRESUMECRITICAL:
+        case PBT_APMRESUMESUSPEND:
+          PostSleepWakeNotification(false);
+          break;
+      }
+      break;
+
+    case WM_CLOSE:  // close request
+      if (mWidgetListener) mWidgetListener->RequestWindowClose(this);
+      result = true;  // abort window closure
+      break;
+
+    case WM_DESTROY:
+      // clean up.
+      DestroyLayerManager();
+      OnDestroy();
+      result = true;
+      break;
+
+    case WM_PAINT:
+      *aRetValue = (int)OnPaint(0);
+      result = true;
+      break;
+
+    case WM_HOTKEY:
+      result = OnHotKey(wParam, lParam);
+      break;
+
+    case WM_SYSCHAR:
+    case WM_CHAR: {
+      MSG nativeMsg = WinUtils::InitMSG(msg, wParam, lParam, mWnd);
+      result = ProcessCharMessage(nativeMsg, nullptr);
+      DispatchPendingEvents();
+    } break;
+
+    case WM_SYSKEYUP:
+    case WM_KEYUP: {
+      MSG nativeMsg = WinUtils::InitMSG(msg, wParam, lParam, mWnd);
+      nativeMsg.time = ::GetMessageTime();
+      result = ProcessKeyUpMessage(nativeMsg, nullptr);
+      DispatchPendingEvents();
+    } break;
+
+    case WM_SYSKEYDOWN:
+    case WM_KEYDOWN: {
+      MSG nativeMsg = WinUtils::InitMSG(msg, wParam, lParam, mWnd);
+      result = ProcessKeyDownMessage(nativeMsg, nullptr);
+      DispatchPendingEvents();
+    } break;
+
+    // Say we've dealt with erasing the background. (This is actually handled in
+    // WM_PAINT, where necessary.)
+    case WM_ERASEBKGND: {
+      *aRetValue = 1;
+      result = true;
+    } break;
+
+    case WM_MOUSEMOVE: {
+      LPARAM lParamScreen = lParamToScreen(lParam);
+      mSimulatedClientArea = IsSimulatedClientArea(GET_X_LPARAM(lParamScreen),
+                                                   GET_Y_LPARAM(lParamScreen));
+
+      if (!mMousePresent && !sIsInMouseCapture) {
+        // First MOUSEMOVE over the client area. Ask for MOUSELEAVE
+        TRACKMOUSEEVENT mTrack;
+        mTrack.cbSize = sizeof(TRACKMOUSEEVENT);
+        mTrack.dwFlags = TME_LEAVE;
+        mTrack.dwHoverTime = 0;
+        mTrack.hwndTrack = mWnd;
+        TrackMouseEvent(&mTrack);
+      }
+      mMousePresent = true;
+
+      // Suppress dispatch of pending events
+      // when mouse moves are generated by widget
+      // creation instead of user input.
+      POINT mp;
+      mp.x = GET_X_LPARAM(lParamScreen);
+      mp.y = GET_Y_LPARAM(lParamScreen);
+      bool userMovedMouse = false;
+      if ((sLastMouseMovePoint.x != mp.x) || (sLastMouseMovePoint.y != mp.y)) {
+        userMovedMouse = true;
+      }
+
+      if (userMovedMouse) {
+        result = DispatchMouseEvent(
+            eMouseMove, wParam, lParam, false, MouseButton::ePrimary,
+            MOUSE_INPUT_SOURCE(),
+            mPointerEvents.GetCachedPointerInfo(msg, wParam));
+        DispatchPendingEvents();
+      }
+    } break;
+
+    case WM_NCMOUSEMOVE: {
+      LPARAM lParamClient = lParamToClient(lParam);
+      if (IsSimulatedClientArea(GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam))) {
+        if (!sIsInMouseCapture) {
+          TRACKMOUSEEVENT mTrack;
+          mTrack.cbSize = sizeof(TRACKMOUSEEVENT);
+          mTrack.dwFlags = TME_LEAVE | TME_NONCLIENT;
+          mTrack.dwHoverTime = 0;
+          mTrack.hwndTrack = mWnd;
+          TrackMouseEvent(&mTrack);
+        }
+        // If we noticed the mouse moving in our draggable region, forward the
+        // message as a normal WM_MOUSEMOVE.
+        SendMessage(mWnd, WM_MOUSEMOVE, 0, lParamClient);
+      } else {
+        // We've transitioned from a draggable area to somewhere else within
+        // the non-client area - perhaps one of the edges of the window for
+        // resizing.
+        mSimulatedClientArea = false;
+      }
+
+      if (mMousePresent && !sIsInMouseCapture && !mSimulatedClientArea) {
+        SendMessage(mWnd, WM_MOUSELEAVE, 0, 0);
+      }
+    } break;
+
+    case WM_LBUTTONDOWN: {
+      result =
+          DispatchMouseEvent(eMouseDown, wParam, lParam, false,
+                             MouseButton::ePrimary, MOUSE_INPUT_SOURCE(),
+                             mPointerEvents.GetCachedPointerInfo(msg, wParam));
+      DispatchPendingEvents();
+    } break;
+
+    case WM_LBUTTONUP: {
+      result =
+          DispatchMouseEvent(eMouseUp, wParam, lParam, false,
+                             MouseButton::ePrimary, MOUSE_INPUT_SOURCE(),
+                             mPointerEvents.GetCachedPointerInfo(msg, wParam));
+      DispatchPendingEvents();
+    } break;
+
+    case WM_NCMOUSELEAVE: {
+      mSimulatedClientArea = false;
+
+      if (EventIsInsideWindow(this)) {
+        // If we're handling WM_NCMOUSELEAVE and the mouse is still over the
+        // window, then by process of elimination, the mouse has moved from the
+        // non-client to client area, so no need to fall-through to the
+        // WM_MOUSELEAVE handler. We also need to re-register for the
+        // WM_MOUSELEAVE message, since according to the documentation at [1],
+        // all tracking requested via TrackMouseEvent is cleared once
+        // WM_NCMOUSELEAVE or WM_MOUSELEAVE fires.
+        // [1]:
+        // https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-trackmouseevent
+        TRACKMOUSEEVENT mTrack;
+        mTrack.cbSize = sizeof(TRACKMOUSEEVENT);
+        mTrack.dwFlags = TME_LEAVE;
+        mTrack.dwHoverTime = 0;
+        mTrack.hwndTrack = mWnd;
+        TrackMouseEvent(&mTrack);
+        break;
+      }
+      // We've transitioned from non-client to outside of the window, so
+      // fall-through to the WM_MOUSELEAVE handler.
+      [[fallthrough]];
+    }
+    case WM_MOUSELEAVE: {
+      if (!mMousePresent) break;
+      if (mSimulatedClientArea) break;
+      mMousePresent = false;
+
+      // Check if the mouse is over the fullscreen transition window, if so
+      // clear sLastMouseMovePoint. This way the WM_MOUSEMOVE we get after the
+      // transition window disappears will not be ignored, even if the mouse
+      // hasn't moved.
+      if (mTransitionWnd && WindowAtMouse() == mTransitionWnd) {
+        sLastMouseMovePoint = {0};
+      }
+
+      // We need to check mouse button states and put them in for
+      // wParam.
+      WPARAM mouseState = (GetKeyState(VK_LBUTTON) ? MK_LBUTTON : 0) |
+                          (GetKeyState(VK_MBUTTON) ? MK_MBUTTON : 0) |
+                          (GetKeyState(VK_RBUTTON) ? MK_RBUTTON : 0);
+      // Synthesize an event position because we don't get one from
+      // WM_MOUSELEAVE.
+      LPARAM pos = lParamToClient(::GetMessagePos());
+      DispatchMouseEvent(eMouseExitFromWidget, mouseState, pos, false,
+                         MouseButton::ePrimary, MOUSE_INPUT_SOURCE());
+    } break;
+
+    case WM_CONTEXTMENU: {
+      // If the context menu is brought up by a touch long-press, then
+      // the APZ code is responsible for dealing with this, so we don't
+      // need to do anything.
+      if (mTouchWindow &&
+          MOUSE_INPUT_SOURCE() == MouseEvent_Binding::MOZ_SOURCE_TOUCH) {
+        MOZ_ASSERT(mAPZC);  // since mTouchWindow is true, APZ must be enabled
+        result = true;
+        break;
+      }
+
+      // If this WM_CONTEXTMENU is triggered by a mouse's secondary button up
+      // event in overscroll gutter, we shouldn't open context menu.
+      if (MOUSE_INPUT_SOURCE() == MouseEvent_Binding::MOZ_SOURCE_MOUSE &&
+          mNeedsToPreventContextMenu) {
+        result = true;
+        break;
+      }
+
+      // if the context menu is brought up from the keyboard, |lParam|
+      // will be -1.
+      LPARAM pos;
+      bool contextMenukey = false;
+      if (lParam == -1) {
+        contextMenukey = true;
+        pos = lParamToClient(GetMessagePos());
+      } else {
+        pos = lParamToClient(lParam);
+      }
+
+      result = DispatchMouseEvent(
+          eContextMenu, wParam, pos, contextMenukey,
+          contextMenukey ? MouseButton::ePrimary : MouseButton::eSecondary,
+          MOUSE_INPUT_SOURCE());
+      if (lParam != -1 && !result && mCustomNonClient &&
+          mDraggableRegion.Contains(GET_X_LPARAM(pos), GET_Y_LPARAM(pos))) {
+        // Blank area hit, throw up the system menu.
+        DisplaySystemMenu(mWnd, mFrameState->GetSizeMode(), mIsRTL,
+                          GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam));
+        result = true;
+      }
+    } break;
+
+    case WM_POINTERLEAVE:
+    case WM_POINTERDOWN:
+    case WM_POINTERUP:
+    case WM_POINTERUPDATE:
+      result = OnPointerEvents(msg, wParam, lParam);
+      if (result) {
+        DispatchPendingEvents();
+      }
+      break;
+
+    case DM_POINTERHITTEST:
+      if (mDmOwner) {
+        UINT contactId = GET_POINTERID_WPARAM(wParam);
+        POINTER_INPUT_TYPE pointerType;
+        if (mPointerEvents.GetPointerType(contactId, &pointerType) &&
+            pointerType == PT_TOUCHPAD) {
+          mDmOwner->SetContact(contactId);
+        }
+      }
+      break;
+
+    case WM_LBUTTONDBLCLK:
+      result = DispatchMouseEvent(eMouseDoubleClick, wParam, lParam, false,
+                                  MouseButton::ePrimary, MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    case WM_MBUTTONDOWN:
+      result = DispatchMouseEvent(eMouseDown, wParam, lParam, false,
+                                  MouseButton::eMiddle, MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    case WM_MBUTTONUP:
+      result = DispatchMouseEvent(eMouseUp, wParam, lParam, false,
+                                  MouseButton::eMiddle, MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    case WM_MBUTTONDBLCLK:
+      result = DispatchMouseEvent(eMouseDoubleClick, wParam, lParam, false,
+                                  MouseButton::eMiddle, MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    case WM_NCMBUTTONDOWN:
+      result = DispatchMouseEvent(eMouseDown, 0, lParamToClient(lParam), false,
+                                  MouseButton::eMiddle, MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    case WM_NCMBUTTONUP:
+      result = DispatchMouseEvent(eMouseUp, 0, lParamToClient(lParam), false,
+                                  MouseButton::eMiddle, MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    case WM_NCMBUTTONDBLCLK:
+      result =
+          DispatchMouseEvent(eMouseDoubleClick, 0, lParamToClient(lParam),
+                             false, MouseButton::eMiddle, MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    case WM_RBUTTONDOWN:
+      result =
+          DispatchMouseEvent(eMouseDown, wParam, lParam, false,
+                             MouseButton::eSecondary, MOUSE_INPUT_SOURCE(),
+                             mPointerEvents.GetCachedPointerInfo(msg, wParam));
+      DispatchPendingEvents();
+      break;
+
+    case WM_RBUTTONUP:
+      result =
+          DispatchMouseEvent(eMouseUp, wParam, lParam, false,
+                             MouseButton::eSecondary, MOUSE_INPUT_SOURCE(),
+                             mPointerEvents.GetCachedPointerInfo(msg, wParam));
+      DispatchPendingEvents();
+      break;
+
+    case WM_RBUTTONDBLCLK:
+      result =
+          DispatchMouseEvent(eMouseDoubleClick, wParam, lParam, false,
+                             MouseButton::eSecondary, MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    case WM_NCRBUTTONDOWN:
+      result =
+          DispatchMouseEvent(eMouseDown, 0, lParamToClient(lParam), false,
+                             MouseButton::eSecondary, MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    case WM_NCRBUTTONUP:
+      result =
+          DispatchMouseEvent(eMouseUp, 0, lParamToClient(lParam), false,
+                             MouseButton::eSecondary, MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    case WM_NCRBUTTONDBLCLK:
+      result = DispatchMouseEvent(eMouseDoubleClick, 0, lParamToClient(lParam),
+                                  false, MouseButton::eSecondary,
+                                  MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    // Windows doesn't provide to customize the behavior of 4th nor 5th button
+    // of mouse.  If 5-button mouse works with standard mouse deriver of
+    // Windows, users cannot disable 4th button (browser back) nor 5th button
+    // (browser forward).  We should allow to do it with our prefs since we can
+    // prevent Windows to generate WM_APPCOMMAND message if WM_XBUTTONUP
+    // messages are not sent to DefWindowProc.
+    case WM_XBUTTONDOWN:
+    case WM_XBUTTONUP:
+    case WM_NCXBUTTONDOWN:
+    case WM_NCXBUTTONUP:
+      *aRetValue = TRUE;
+      switch (GET_XBUTTON_WPARAM(wParam)) {
+        case XBUTTON1:
+          result = !Preferences::GetBool("mousebutton.4th.enabled", true);
+          break;
+        case XBUTTON2:
+          result = !Preferences::GetBool("mousebutton.5th.enabled", true);
+          break;
+        default:
+          break;
+      }
+      break;
+
+    case WM_SIZING: {
+      if (mAspectRatio > 0) {
+        LPRECT rect = (LPRECT)lParam;
+        int32_t newWidth, newHeight;
+
+        // The following conditions and switch statement borrow heavily from the
+        // Chromium source code from
+        // https://chromium.googlesource.com/chromium/src/+/456d6e533cfb4531995e0ef52c279d4b5aa8a352/ui/views/window/window_resize_utils.cc#45
+        if (wParam == WMSZ_LEFT || wParam == WMSZ_RIGHT ||
+            wParam == WMSZ_TOPLEFT || wParam == WMSZ_BOTTOMLEFT) {
+          newWidth = rect->right - rect->left;
+          newHeight = newWidth / mAspectRatio;
+          if (newHeight < mSizeConstraints.mMinSize.height) {
+            newHeight = mSizeConstraints.mMinSize.height;
+            newWidth = newHeight * mAspectRatio;
+          } else if (newHeight > mSizeConstraints.mMaxSize.height) {
+            newHeight = mSizeConstraints.mMaxSize.height;
+            newWidth = newHeight * mAspectRatio;
+          }
+        } else {
+          newHeight = rect->bottom - rect->top;
+          newWidth = newHeight * mAspectRatio;
+          if (newWidth < mSizeConstraints.mMinSize.width) {
+            newWidth = mSizeConstraints.mMinSize.width;
+            newHeight = newWidth / mAspectRatio;
+          } else if (newWidth > mSizeConstraints.mMaxSize.width) {
+            newWidth = mSizeConstraints.mMaxSize.width;
+            newHeight = newWidth / mAspectRatio;
+          }
+        }
+
+        switch (wParam) {
+          case WMSZ_RIGHT:
+          case WMSZ_BOTTOM:
+            rect->right = newWidth + rect->left;
+            rect->bottom = rect->top + newHeight;
+            break;
+          case WMSZ_TOP:
+            rect->right = newWidth + rect->left;
+            rect->top = rect->bottom - newHeight;
+            break;
+          case WMSZ_LEFT:
+          case WMSZ_TOPLEFT:
+            rect->left = rect->right - newWidth;
+            rect->top = rect->bottom - newHeight;
+            break;
+          case WMSZ_TOPRIGHT:
+            rect->right = rect->left + newWidth;
+            rect->top = rect->bottom - newHeight;
+            break;
+          case WMSZ_BOTTOMLEFT:
+            rect->left = rect->right - newWidth;
+            rect->bottom = rect->top + newHeight;
+            break;
+          case WMSZ_BOTTOMRIGHT:
+            rect->right = rect->left + newWidth;
+            rect->bottom = rect->top + newHeight;
+            break;
+        }
+      }
+
+      // When we get WM_ENTERSIZEMOVE we don't know yet if we're in a live
+      // resize or move event. Instead we wait for first VM_SIZING message
+      // within a ENTERSIZEMOVE to consider this a live resize event.
+      if (mResizeState == IN_SIZEMOVE) {
+        mResizeState = RESIZING;
+        NotifyLiveResizeStarted();
+      }
+      break;
+    }
+
+    case WM_MOVING:
+      FinishLiveResizing(MOVING);
+      if (WinUtils::IsPerMonitorDPIAware()) {
+        // Sometimes, we appear to miss a WM_DPICHANGED message while moving
+        // a window around. Therefore, call ChangedDPI and ResetLayout here
+        // if it appears that the window's scaling is not what we expect.
+        // This causes the prescontext and appshell window management code to
+        // check the appUnitsPerDevPixel value and current widget size, and
+        // refresh them if necessary. If nothing has changed, these calls will
+        // return without actually triggering any extra reflow or painting.
+        if (WinUtils::LogToPhysFactor(mWnd) != mDefaultScale) {
+          ChangedDPI();
+          ResetLayout();
+          if (mWidgetListener) {
+            mWidgetListener->UIResolutionChanged();
+          }
+        }
+      }
+      break;
+
+    case WM_ENTERSIZEMOVE: {
+      if (mResizeState == NOT_RESIZING) {
+        mResizeState = IN_SIZEMOVE;
+      }
+      break;
+    }
+
+    case WM_EXITSIZEMOVE: {
+      FinishLiveResizing(NOT_RESIZING);
+
+      if (!sIsInMouseCapture) {
+        NotifySizeMoveDone();
+      }
+
+      // Windows spins a separate hidden event loop when moving a window so we
+      // don't hear mouse events during this time and WM_EXITSIZEMOVE is fired
+      // when the hidden event loop exits. We set mDraggingWindowWithMouse to
+      // true in WM_NCLBUTTONDOWN when we started moving the window with the
+      // mouse so we know that if mDraggingWindowWithMouse is true, we can send
+      // a mouse up event.
+      if (mDraggingWindowWithMouse) {
+        mDraggingWindowWithMouse = false;
+        result = DispatchMouseEvent(
+            eMouseUp, wParam, lParam, false, MouseButton::ePrimary,
+            MOUSE_INPUT_SOURCE(),
+            mPointerEvents.GetCachedPointerInfo(msg, wParam));
+      }
+
+      break;
+    }
+
+    case WM_DISPLAYCHANGE: {
+      ScreenHelperWin::RefreshScreens();
+      if (mWidgetListener) {
+        mWidgetListener->UIResolutionChanged();
+      }
+      break;
+    }
+
+    case WM_NCLBUTTONDBLCLK:
+      DispatchMouseEvent(eMouseDoubleClick, 0, lParamToClient(lParam), false,
+                         MouseButton::ePrimary, MOUSE_INPUT_SOURCE());
+      result = DispatchMouseEvent(eMouseUp, 0, lParamToClient(lParam), false,
+                                  MouseButton::ePrimary, MOUSE_INPUT_SOURCE());
+      DispatchPendingEvents();
+      break;
+
+    case WM_NCLBUTTONDOWN: {
+      // Dispatch a custom event when this happens in the draggable region, so
+      // that non-popup-based panels can react to it. This doesn't send an
+      // actual mousedown event because that would break dragging or interfere
+      // with other mousedown handling in the caption area.
+      if (ClientMarginHitTestPoint(GET_X_LPARAM(lParam),
+                                   GET_Y_LPARAM(lParam)) == HTCAPTION) {
+        DispatchCustomEvent(u"draggableregionleftmousedown"_ns);
+        mDraggingWindowWithMouse = true;
+      }
+
+      if (IsWindowButton(wParam) && mCustomNonClient) {
+        DispatchMouseEvent(eMouseDown, wParamFromGlobalMouseState(),
+                           lParamToClient(lParam), false, MouseButton::ePrimary,
+                           MOUSE_INPUT_SOURCE(), nullptr, true);
+        DispatchPendingEvents();
+        result = true;
+      }
+      break;
+    }
+
+    case WM_APPCOMMAND: {
+      MSG nativeMsg = WinUtils::InitMSG(msg, wParam, lParam, mWnd);
+      result = HandleAppCommandMsg(nativeMsg, aRetValue);
+      break;
+    }
+
+    // The WM_ACTIVATE event is fired when a window is raised or lowered,
+    // and the loword of wParam specifies which. But we don't want to tell
+    // the focus system about this until the WM_SETFOCUS or WM_KILLFOCUS
+    // events are fired. Instead, set either the sJustGotActivate or
+    // gJustGotDeactivate flags and activate/deactivate once the focus
+    // events arrive.
+    case WM_ACTIVATE: {
+      int32_t fActive = LOWORD(wParam);
+      if (mWidgetListener) {
+        if (WA_INACTIVE == fActive) {
+          // when minimizing a window, the deactivation and focus events will
+          // be fired in the reverse order. Instead, just deactivate right away.
+          // This can also happen when a modal system dialog is opened, so check
+          // if the last window to receive the WM_KILLFOCUS message was this one
+          // or a child of this one.
+          if (HIWORD(wParam) ||
+              (mLastKillFocusWindow &&
+               (GetTopLevelForFocus(mLastKillFocusWindow) == mWnd))) {
+            DispatchFocusToTopLevelWindow(false);
+          } else {
+            sJustGotDeactivate = true;
+          }
+          if (mIsTopWidgetWindow) {
+            mLastKeyboardLayout = KeyboardLayout::GetLayout();
+          }
+        } else {
+          StopFlashing();
+
+          sJustGotActivate = true;
+          WidgetMouseEvent event(true, eMouseActivate, this,
+                                 WidgetMouseEvent::eReal);
+          InitEvent(event);
+          ModifierKeyState modifierKeyState;
+          modifierKeyState.InitInputEvent(event);
+          DispatchInputEvent(&event);
+          if (sSwitchKeyboardLayout && mLastKeyboardLayout)
+            ActivateKeyboardLayout(mLastKeyboardLayout, 0);
+
+#ifdef ACCESSIBILITY
+          a11y::LazyInstantiator::ResetUiaDetectionCache();
+#endif
+        }
+      }
+    } break;
+
+    case WM_ACTIVATEAPP: {
+      // Bug 1851991: Sometimes this can be called before gfxPlatform::Init
+      // when a window is created very early. In that case we just forego
+      // setting this and accept the GPU process might briefly run at a lower
+      // priority.
+      if (GPUProcessManager::Get()) {
+        GPUProcessManager::Get()->SetAppInForeground(wParam);
+      }
+    } break;
+
+    case WM_MOUSEACTIVATE:
+      // A popup with a parent owner should not be activated when clicked but
+      // should still allow the mouse event to be fired, so the return value
+      // is set to MA_NOACTIVATE. But if the owner isn't the frontmost window,
+      // just use default processing so that the window is activated.
+      if (IsPopup() && IsOwnerForegroundWindow()) {
+        *aRetValue = MA_NOACTIVATE;
+        result = true;
+      }
+      break;
+
+    case WM_WINDOWPOSCHANGING: {
+      LPWINDOWPOS info = (LPWINDOWPOS)lParam;
+      OnWindowPosChanging(info);
+      result = true;
+    } break;
+
+    // Workaround for race condition in explorer.exe.
+    case MOZ_WM_FULLSCREEN_STATE_UPDATE: {
+      TaskbarConcealer::OnAsyncStateUpdateRequest(mWnd);
+      result = true;
+    } break;
+
+    case WM_GETMINMAXINFO: {
+      MINMAXINFO* mmi = (MINMAXINFO*)lParam;
+      // Set the constraints. The minimum size should also be constrained to the
+      // default window maximum size so that it fits on screen.
+      mmi->ptMinTrackSize.x =
+          std::min((int32_t)mmi->ptMaxTrackSize.x,
+                   std::max((int32_t)mmi->ptMinTrackSize.x,
+                            mSizeConstraints.mMinSize.width));
+      mmi->ptMinTrackSize.y =
+          std::min((int32_t)mmi->ptMaxTrackSize.y,
+                   std::max((int32_t)mmi->ptMinTrackSize.y,
+                            mSizeConstraints.mMinSize.height));
+      mmi->ptMaxTrackSize.x = std::min((int32_t)mmi->ptMaxTrackSize.x,
+                                       mSizeConstraints.mMaxSize.width);
+      mmi->ptMaxTrackSize.y = std::min((int32_t)mmi->ptMaxTrackSize.y,
+                                       mSizeConstraints.mMaxSize.height);
+    } break;
+
+    case WM_SETFOCUS: {
+      WndProcUrgentInvocation::Marker _marker;
+
+      // If previous focused window isn't ours, it must have received the
+      // redirected message.  So, we should forget it.
+      if (!WinUtils::IsOurProcessWindow(HWND(wParam))) {
+        RedirectedKeyDownMessageManager::Forget();
+      }
+      if (sJustGotActivate) {
+        DispatchFocusToTopLevelWindow(true);
+      }
+      TaskbarConcealer::OnFocusAcquired(this);
+    } break;
+
+    case WM_KILLFOCUS:
+      if (sJustGotDeactivate) {
+        DispatchFocusToTopLevelWindow(false);
+      } else {
+        mLastKillFocusWindow = mWnd;
+      }
+      break;
+
+    case WM_WINDOWPOSCHANGED: {
+      WINDOWPOS* wp = (LPWINDOWPOS)lParam;
+      OnWindowPosChanged(wp);
+      TaskbarConcealer::OnWindowPosChanged(this);
+      result = true;
+    } break;
+
+    case WM_INPUTLANGCHANGEREQUEST:
+      *aRetValue = TRUE;
+      result = false;
+      break;
+
+    case WM_INPUTLANGCHANGE:
+      KeyboardLayout::GetInstance()->OnLayoutChange(
+          reinterpret_cast<HKL>(lParam));
+      nsBidiKeyboard::OnLayoutChange();
+      result = false;  // always pass to child window
+      break;
+
+    case WM_DESTROYCLIPBOARD: {
+      nsIClipboard* clipboard;
+      nsresult rv = CallGetService(kCClipboardCID, &clipboard);
+      if (NS_SUCCEEDED(rv)) {
+        clipboard->EmptyClipboard(nsIClipboard::kGlobalClipboard);
+        NS_RELEASE(clipboard);
+      }
+    } break;
+
+#ifdef ACCESSIBILITY
+    case WM_GETOBJECT: {
+      *aRetValue = 0;
+      // Do explicit casting to make it working on 64bit systems (see bug 649236
+      // for details).
+      int32_t objId = static_cast<DWORD>(lParam);
+      if (objId == OBJID_CLIENT) {  // oleacc.dll will be loaded dynamically
+        RefPtr<IAccessible> root(
+            a11y::LazyInstantiator::GetRootAccessible(mWnd));
+        if (root) {
+          *aRetValue = LresultFromObject(IID_IAccessible, wParam, root);
+          a11y::LazyInstantiator::EnableBlindAggregation(mWnd);
+          result = true;
+        }
+      }
+    } break;
+#endif
+
+    case WM_SYSCOMMAND: {
+      WPARAM const filteredWParam = (wParam & 0xFFF0);
+
+      // SC_CLOSE may trigger a synchronous confirmation prompt. If we're in the
+      // middle of something important, put off responding to it.
+      if (filteredWParam == SC_CLOSE && WndProcUrgentInvocation::IsActive()) {
+        ::PostMessageW(mWnd, msg, wParam, lParam);
+        result = true;
+        break;
+      }
+
+      if (mFrameState->GetSizeMode() == nsSizeMode_Fullscreen &&
+          filteredWParam == SC_RESTORE &&
+          GetCurrentShowCmd(mWnd) != SW_SHOWMINIMIZED) {
+        mFrameState->EnsureFullscreenMode(false);
+        result = true;
+      }
+
+      // Handle the system menu manually when we're in full screen mode
+      // so we can set the appropriate options.
+      if (filteredWParam == SC_KEYMENU && lParam == VK_SPACE &&
+          mFrameState->GetSizeMode() == nsSizeMode_Fullscreen) {
+        DisplaySystemMenu(mWnd, mFrameState->GetSizeMode(), mIsRTL,
+                          MOZ_SYSCONTEXT_X_POS, MOZ_SYSCONTEXT_Y_POS);
+        result = true;
+      }
+    } break;
+
+    case WM_DPICHANGED: {
+      LPRECT rect = (LPRECT)lParam;
+      OnDPIChanged(rect->left, rect->top, rect->right - rect->left,
+                   rect->bottom - rect->top);
+      break;
+    }
+
+    /* Gesture support events */
+    case WM_TABLET_QUERYSYSTEMGESTURESTATUS:
+      // According to MS samples, this must be handled to enable
+      // rotational support in multi-touch drivers.
+      result = true;
+      *aRetValue = TABLET_ROTATE_GESTURE_ENABLE;
+      break;
+
+    case WM_TOUCH:
+      result = OnTouch(wParam, lParam);
+      if (result) {
+        *aRetValue = 0;
+      }
+      break;
+
+    case WM_GESTURE:
+      result = OnGesture(wParam, lParam);
+      break;
+
+    case WM_GESTURENOTIFY: {
+      if (mWindowType != WindowType::Invisible) {
+        // A GestureNotify event is dispatched to decide which single-finger
+        // panning direction should be active (including none) and if pan
+        // feedback should be displayed. Java and plugin windows can make their
+        // own calls.
+
+        GESTURENOTIFYSTRUCT* gestureinfo = (GESTURENOTIFYSTRUCT*)lParam;
+        nsPointWin touchPoint;
+        touchPoint = gestureinfo->ptsLocation;
+        touchPoint.ScreenToClient(mWnd);
+        WidgetGestureNotifyEvent gestureNotifyEvent(true, eGestureNotify, this);
+        gestureNotifyEvent.mRefPoint =
+            LayoutDeviceIntPoint::FromUnknownPoint(touchPoint);
+        nsEventStatus status;
+        DispatchEvent(&gestureNotifyEvent, status);
+        mDisplayPanFeedback = gestureNotifyEvent.mDisplayPanFeedback;
+        if (!mTouchWindow)
+          mGesture.SetWinGestureSupport(mWnd, gestureNotifyEvent.mPanDirection);
+      }
+      result = false;  // should always bubble to DefWindowProc
+    } break;
+
+    case WM_CLEAR: {
+      WidgetContentCommandEvent command(true, eContentCommandDelete, this);
+      DispatchWindowEvent(command);
+      result = true;
+    } break;
+
+    case WM_CUT: {
+      WidgetContentCommandEvent command(true, eContentCommandCut, this);
+      DispatchWindowEvent(command);
+      result = true;
+    } break;
+
+    case WM_COPY: {
+      WidgetContentCommandEvent command(true, eContentCommandCopy, this);
+      DispatchWindowEvent(command);
+      result = true;
+    } break;
+
+    case WM_PASTE: {
+      WidgetContentCommandEvent command(true, eContentCommandPaste, this);
+      DispatchWindowEvent(command);
+      result = true;
+    } break;
+
+    case EM_UNDO: {
+      WidgetContentCommandEvent command(true, eContentCommandUndo, this);
+      DispatchWindowEvent(command);
+      *aRetValue = (LRESULT)(command.mSucceeded && command.mIsEnabled);
+      result = true;
+    } break;
+
+    case EM_REDO: {
+      WidgetContentCommandEvent command(true, eContentCommandRedo, this);
+      DispatchWindowEvent(command);
+      *aRetValue = (LRESULT)(command.mSucceeded && command.mIsEnabled);
+      result = true;
+    } break;
+
+    case EM_CANPASTE: {
+      // Support EM_CANPASTE message only when wParam isn't specified or
+      // is plain text format.
+      if (wParam == 0 || wParam == CF_TEXT || wParam == CF_UNICODETEXT) {
+        WidgetContentCommandEvent command(true, eContentCommandPaste, this,
+                                          true);
+        DispatchWindowEvent(command);
+        *aRetValue = (LRESULT)(command.mSucceeded && command.mIsEnabled);
+        result = true;
+      }
+    } break;
+
+    case EM_CANUNDO: {
+      WidgetContentCommandEvent command(true, eContentCommandUndo, this, true);
+      DispatchWindowEvent(command);
+      *aRetValue = (LRESULT)(command.mSucceeded && command.mIsEnabled);
+      result = true;
+    } break;
+
+    case EM_CANREDO: {
+      WidgetContentCommandEvent command(true, eContentCommandRedo, this, true);
+      DispatchWindowEvent(command);
+      *aRetValue = (LRESULT)(command.mSucceeded && command.mIsEnabled);
+      result = true;
+    } break;
+
+    case MOZ_WM_SKEWFIX: {
+      TimeStamp skewStamp;
+      if (CurrentWindowsTimeGetter::GetAndClearBackwardsSkewStamp(wParam,
+                                                                  &skewStamp)) {
+        TimeConverter().CompensateForBackwardsSkew(::GetMessageTime(),
+                                                   skewStamp);
+      }
+    } break;
+
+    default: {
+      if (msg == nsAppShell::GetTaskbarButtonCreatedMessage()) {
+        SetHasTaskbarIconBeenCreated();
+      }
+    } break;
+  }
+
+  //*aRetValue = result;
+  if (mWnd) {
+    return result;
+  } else {
+    // Events which caused mWnd destruction and aren't consumed
+    // will crash during the Windows default processing.
+    return true;
+  }
+}
+
+void nsWindow::FinishLiveResizing(ResizeState aNewState) {
+  if (mResizeState == RESIZING) {
+    NotifyLiveResizeStopped();
+  }
+  mResizeState = aNewState;
+  ForcePresent();
+}
+
+/**************************************************************
+ *
+ * SECTION: Event processing helpers
+ *
+ * Special processing for certain event types and
+ * synthesized events.
+ *
+ **************************************************************/
+
+LayoutDeviceIntMargin nsWindow::NonClientSizeMargin(
+    const LayoutDeviceIntMargin& aNonClientOffset) const {
+  return LayoutDeviceIntMargin(mCaptionHeight - aNonClientOffset.top,
+                               mHorResizeMargin - aNonClientOffset.right,
+                               mVertResizeMargin - aNonClientOffset.bottom,
+                               mHorResizeMargin - aNonClientOffset.left);
+}
+
+int32_t nsWindow::ClientMarginHitTestPoint(int32_t aX, int32_t aY) {
+  const nsSizeMode sizeMode = mFrameState->GetSizeMode();
+  if (sizeMode == nsSizeMode_Minimized || sizeMode == nsSizeMode_Fullscreen) {
+    return HTCLIENT;
+  }
+
+  // Calculations are done in screen coords
+  const LayoutDeviceIntRect winRect = GetScreenBounds();
+  const LayoutDeviceIntPoint point(aX, aY);
+
+  // hit return constants:
+  // HTBORDER                     - non-resizable border
+  // HTBOTTOM, HTLEFT, HTRIGHT, HTTOP - resizable border
+  // HTBOTTOMLEFT, HTBOTTOMRIGHT  - resizable corner
+  // HTTOPLEFT, HTTOPRIGHT        - resizable corner
+  // HTCAPTION                    - general title bar area
+  // HTCLIENT                     - area considered the client
+  // HTCLOSE                      - hovering over the close button
+  // HTMAXBUTTON                  - maximize button
+  // HTMINBUTTON                  - minimize button
+
+  int32_t testResult = HTCLIENT;
+  const bool isResizable =
+      sizeMode != nsSizeMode_Maximized &&
+      (mBorderStyle &
+       (BorderStyle::All | BorderStyle::ResizeH | BorderStyle::Default));
+
+  LayoutDeviceIntMargin nonClientSizeMargin = NonClientSizeMargin();
+
+  // Ensure being accessible to borders of window.  Even if contents are in
+  // this area, the area must behave as border.
+  nonClientSizeMargin.EnsureAtLeast(
+      LayoutDeviceIntMargin(kResizableBorderMinSize, kResizableBorderMinSize,
+                            kResizableBorderMinSize, kResizableBorderMinSize));
+
+  LayoutDeviceIntRect clientRect = winRect;
+  clientRect.Deflate(nonClientSizeMargin);
+
+  const bool allowContentOverride =
+      sizeMode == nsSizeMode_Maximized || clientRect.Contains(point);
+
+  // The border size.  If there is no content under mouse cursor, the border
+  // size should be larger than the values in system settings.  Otherwise,
+  // contents under the mouse cursor should be able to override the behavior.
+  // E.g., user must expect that Firefox button always opens the popup menu
+  // even when the user clicks on the above edge of it.
+  LayoutDeviceIntMargin borderSize = nonClientSizeMargin;
+  borderSize.EnsureAtLeast(
+      LayoutDeviceIntMargin(mVertResizeMargin, mHorResizeMargin,
+                            mVertResizeMargin, mHorResizeMargin));
+
+  bool top = false;
+  bool bottom = false;
+  bool left = false;
+  bool right = false;
+
+  if (point.y >= winRect.y && point.y < winRect.y + borderSize.top) {
+    top = true;
+  } else if (point.y <= winRect.YMost() &&
+             point.y > winRect.YMost() - borderSize.bottom) {
+    bottom = true;
+  }
+
+  // (the 2x case here doubles the resize area for corners)
+  int multiplier = (top || bottom) ? 2 : 1;
+  if (point.x >= winRect.x &&
+      point.x < winRect.x + (multiplier * borderSize.left)) {
+    left = true;
+  } else if (point.x <= winRect.XMost() &&
+             point.x > winRect.XMost() - (multiplier * borderSize.right)) {
+    right = true;
+  }
+
+  bool inResizeRegion = false;
+  if (isResizable) {
+    if (top) {
+      testResult = HTTOP;
+      if (left) {
+        testResult = HTTOPLEFT;
+      } else if (right) {
+        testResult = HTTOPRIGHT;
+      }
+    } else if (bottom) {
+      testResult = HTBOTTOM;
+      if (left) {
+        testResult = HTBOTTOMLEFT;
+      } else if (right) {
+        testResult = HTBOTTOMRIGHT;
+      }
+    } else {
+      if (left) {
+        testResult = HTLEFT;
+      }
+      if (right) {
+        testResult = HTRIGHT;
+      }
+    }
+    inResizeRegion = (testResult != HTCLIENT);
+  } else {
+    if (top) {
+      testResult = HTCAPTION;
+    } else if (bottom || left || right) {
+      testResult = HTBORDER;
+    }
+  }
+
+  if (!sIsInMouseCapture && allowContentOverride) {
+    {
+      POINT pt = {aX, aY};
+      ::ScreenToClient(mWnd, &pt);
+
+      if (pt.x == mCachedHitTestPoint.x.value &&
+          pt.y == mCachedHitTestPoint.y.value &&
+          TimeStamp::Now() - mCachedHitTestTime <
+              TimeDuration::FromMilliseconds(HITTEST_CACHE_LIFETIME_MS)) {
+        return mCachedHitTestResult;
+      }
+
+      mCachedHitTestPoint = {pt.x, pt.y};
+      mCachedHitTestTime = TimeStamp::Now();
+    }
+
+    auto pt = mCachedHitTestPoint;
+
+    if (mWindowBtnRect[WindowButtonType::Minimize].Contains(pt)) {
+      testResult = HTMINBUTTON;
+    } else if (mWindowBtnRect[WindowButtonType::Maximize].Contains(pt)) {
+      testResult = HTMAXBUTTON;
+    } else if (mWindowBtnRect[WindowButtonType::Close].Contains(pt)) {
+      testResult = HTCLOSE;
+    } else if (!inResizeRegion) {
+      // If we're in the resize region, avoid overriding that with either a
+      // drag or a client result; resize takes priority over either (but not
+      // over the window controls, which is why we check this after those).
+      if (mDraggableRegion.Contains(pt)) {
+        testResult = HTCAPTION;
+      } else {
+        testResult = HTCLIENT;
+      }
+    }
+
+    mCachedHitTestResult = testResult;
+  }
+
+  return testResult;
+}
+
+bool nsWindow::IsSimulatedClientArea(int32_t screenX, int32_t screenY) {
+  int32_t testResult = ClientMarginHitTestPoint(screenX, screenY);
+  return testResult == HTCAPTION || IsWindowButton(testResult);
+}
+
+bool nsWindow::IsWindowButton(int32_t hitTestResult) {
+  return hitTestResult == HTMINBUTTON || hitTestResult == HTMAXBUTTON ||
+         hitTestResult == HTCLOSE;
+}
+
+TimeStamp nsWindow::GetMessageTimeStamp(LONG aEventTime) const {
+  CurrentWindowsTimeGetter getCurrentTime(mWnd);
+  return TimeConverter().GetTimeStampFromSystemTime(aEventTime, getCurrentTime);
+}
+
+void nsWindow::PostSleepWakeNotification(const bool aIsSleepMode) {
+  // Retain the previous mode that was notified to observers
+  static bool sWasSleepMode = false;
+
+  // Only notify observers if mode changed
+  if (aIsSleepMode == sWasSleepMode) return;
+
+  sWasSleepMode = aIsSleepMode;
+
+  nsCOMPtr<nsIObserverService> observerService =
+      mozilla::services::GetObserverService();
+  if (observerService)
+    observerService->NotifyObservers(nullptr,
+                                     aIsSleepMode
+                                         ? NS_WIDGET_SLEEP_OBSERVER_TOPIC
+                                         : NS_WIDGET_WAKE_OBSERVER_TOPIC,
+                                     nullptr);
+}
+
+LRESULT nsWindow::ProcessCharMessage(const MSG& aMsg, bool* aEventDispatched) {
+  if (IMEHandler::IsComposingOn(this)) {
+    IMEHandler::NotifyIME(this, REQUEST_TO_COMMIT_COMPOSITION);
+  }
+  // These must be checked here too as a lone WM_CHAR could be received
+  // if a child window didn't handle it (for example Alt+Space in a content
+  // window)
+  ModifierKeyState modKeyState;
+  NativeKey nativeKey(this, aMsg, modKeyState);
+  return static_cast<LRESULT>(nativeKey.HandleCharMessage(aEventDispatched));
+}
+
+LRESULT nsWindow::ProcessKeyUpMessage(const MSG& aMsg, bool* aEventDispatched) {
+  ModifierKeyState modKeyState;
+  NativeKey nativeKey(this, aMsg, modKeyState);
+  bool result = nativeKey.HandleKeyUpMessage(aEventDispatched);
+  if (aMsg.wParam == VK_F10) {
+    // Bug 1382199: Windows default behavior will trigger the System menu bar
+    // when F10 is released. Among other things, this causes the System menu bar
+    // to appear when a web page overrides the contextmenu event. We *never*
+    // want this default behavior, so eat this key (never pass it to Windows).
+    return true;
+  }
+  return result;
+}
+
+LRESULT nsWindow::ProcessKeyDownMessage(const MSG& aMsg,
+                                        bool* aEventDispatched) {
+  // If this method doesn't call NativeKey::HandleKeyDownMessage(), this method
+  // must clean up the redirected message information itself.  For more
+  // information, see above comment of
+  // RedirectedKeyDownMessageManager::AutoFlusher class definition in
+  // KeyboardLayout.h.
+  RedirectedKeyDownMessageManager::AutoFlusher redirectedMsgFlusher(this, aMsg);
+
+  ModifierKeyState modKeyState;
+
+  NativeKey nativeKey(this, aMsg, modKeyState);
+  LRESULT result =
+      static_cast<LRESULT>(nativeKey.HandleKeyDownMessage(aEventDispatched));
+  // HandleKeyDownMessage cleaned up the redirected message information
+  // itself, so, we should do nothing.
+  redirectedMsgFlusher.Cancel();
+
+  if (aMsg.wParam == VK_MENU ||
+      (aMsg.wParam == VK_F10 && !modKeyState.IsShift())) {
+    // We need to let Windows handle this keypress,
+    // by returning false, if there's a native menu
+    // bar somewhere in our containing window hierarchy.
+    // Otherwise we handle the keypress and don't pass
+    // it on to Windows, by returning true.
+    bool hasNativeMenu = false;
+    HWND hWnd = mWnd;
+    while (hWnd) {
+      if (::GetMenu(hWnd)) {
+        hasNativeMenu = true;
+        break;
+      }
+      hWnd = ::GetParent(hWnd);
+    }
+    result = !hasNativeMenu;
+  }
+
+  return result;
+}
+
+nsresult nsWindow::SynthesizeNativeKeyEvent(
+    int32_t aNativeKeyboardLayout, int32_t aNativeKeyCode,
+    uint32_t aModifierFlags, const nsAString& aCharacters,
+    const nsAString& aUnmodifiedCharacters, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "keyevent");
+
+  KeyboardLayout* keyboardLayout = KeyboardLayout::GetInstance();
+  return keyboardLayout->SynthesizeNativeKeyEvent(
+      this, aNativeKeyboardLayout, aNativeKeyCode, aModifierFlags, aCharacters,
+      aUnmodifiedCharacters);
+}
+
+nsresult nsWindow::SynthesizeNativeMouseEvent(
+    LayoutDeviceIntPoint aPoint, NativeMouseMessage aNativeMessage,
+    MouseButton aButton, nsIWidget::Modifiers aModifierFlags,
+    nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "mouseevent");
+
+  INPUT input;
+  memset(&input, 0, sizeof(input));
+
+  // TODO (bug 1693240):
+  // Now, we synthesize native mouse events asynchronously since we want to
+  // synthesize the event on the front window at the point. However, Windows
+  // does not provide a way to set modifier only while a mouse message is
+  // being handled, and MOUSEEVENTF_MOVE may be coalesced by Windows.  So, we
+  // need a trick for handling it.
+
+  switch (aNativeMessage) {
+    case NativeMouseMessage::Move:
+      input.mi.dwFlags = MOUSEEVENTF_MOVE;
+      // Reset sLastMouseMovePoint so that even if we're moving the mouse
+      // to the position it's already at, we still dispatch a mousemove
+      // event, because the callers of this function expect that.
+      sLastMouseMovePoint = {0};
+      break;
+    case NativeMouseMessage::ButtonDown:
+    case NativeMouseMessage::ButtonUp: {
+      const bool isDown = aNativeMessage == NativeMouseMessage::ButtonDown;
+      switch (aButton) {
+        case MouseButton::ePrimary:
+          input.mi.dwFlags = isDown ? MOUSEEVENTF_LEFTDOWN : MOUSEEVENTF_LEFTUP;
+          break;
+        case MouseButton::eMiddle:
+          input.mi.dwFlags =
+              isDown ? MOUSEEVENTF_MIDDLEDOWN : MOUSEEVENTF_MIDDLEUP;
+          break;
+        case MouseButton::eSecondary:
+          input.mi.dwFlags =
+              isDown ? MOUSEEVENTF_RIGHTDOWN : MOUSEEVENTF_RIGHTUP;
+          break;
+        case MouseButton::eX1:
+          input.mi.dwFlags = isDown ? MOUSEEVENTF_XDOWN : MOUSEEVENTF_XUP;
+          input.mi.mouseData = XBUTTON1;
+          break;
+        case MouseButton::eX2:
+          input.mi.dwFlags = isDown ? MOUSEEVENTF_XDOWN : MOUSEEVENTF_XUP;
+          input.mi.mouseData = XBUTTON2;
+          break;
+        default:
+          return NS_ERROR_INVALID_ARG;
+      }
+      break;
+    }
+    case NativeMouseMessage::EnterWindow:
+    case NativeMouseMessage::LeaveWindow:
+      MOZ_ASSERT_UNREACHABLE("Non supported mouse event on Windows");
+      return NS_ERROR_INVALID_ARG;
+  }
+
+  input.type = INPUT_MOUSE;
+  ::SetCursorPos(aPoint.x, aPoint.y);
+  ::SendInput(1, &input, sizeof(INPUT));
+
+  return NS_OK;
+}
+
+nsresult nsWindow::SynthesizeNativeMouseScrollEvent(
+    LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage, double aDeltaX,
+    double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+    uint32_t aAdditionalFlags, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "mousescrollevent");
+  return MouseScrollHandler::SynthesizeNativeMouseScrollEvent(
+      this, aPoint, aNativeMessage,
+      (aNativeMessage == WM_MOUSEWHEEL || aNativeMessage == WM_VSCROLL)
+          ? static_cast<int32_t>(aDeltaY)
+          : static_cast<int32_t>(aDeltaX),
+      aModifierFlags, aAdditionalFlags);
+}
+
+nsresult nsWindow::SynthesizeNativeTouchpadPan(TouchpadGesturePhase aEventPhase,
+                                               LayoutDeviceIntPoint aPoint,
+                                               double aDeltaX, double aDeltaY,
+                                               int32_t aModifierFlags,
+                                               nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchpadpanevent");
+  DirectManipulationOwner::SynthesizeNativeTouchpadPan(
+      this, aEventPhase, aPoint, aDeltaX, aDeltaY, aModifierFlags);
+  return NS_OK;
+}
+
+static void MaybeLogPosChanged(HWND aWnd, WINDOWPOS* wp) {
+#ifdef WINSTATE_DEBUG_OUTPUT
+  if (aWnd == WinUtils::GetTopLevelHWND(aWnd)) {
+    MOZ_LOG(gWindowsLog, LogLevel::Info, ("*** OnWindowPosChanged: [  top] "));
+  } else {
+    MOZ_LOG(gWindowsLog, LogLevel::Info, ("*** OnWindowPosChanged: [child] "));
+  }
+  MOZ_LOG(gWindowsLog, LogLevel::Info, ("WINDOWPOS flags:"));
+  if (wp->flags & SWP_FRAMECHANGED) {
+    MOZ_LOG(gWindowsLog, LogLevel::Info, ("SWP_FRAMECHANGED "));
+  }
+  if (wp->flags & SWP_SHOWWINDOW) {
+    MOZ_LOG(gWindowsLog, LogLevel::Info, ("SWP_SHOWWINDOW "));
+  }
+  if (wp->flags & SWP_NOSIZE) {
+    MOZ_LOG(gWindowsLog, LogLevel::Info, ("SWP_NOSIZE "));
+  }
+  if (wp->flags & SWP_HIDEWINDOW) {
+    MOZ_LOG(gWindowsLog, LogLevel::Info, ("SWP_HIDEWINDOW "));
+  }
+  if (wp->flags & SWP_NOZORDER) {
+    MOZ_LOG(gWindowsLog, LogLevel::Info, ("SWP_NOZORDER "));
+  }
+  if (wp->flags & SWP_NOACTIVATE) {
+    MOZ_LOG(gWindowsLog, LogLevel::Info, ("SWP_NOACTIVATE "));
+  }
+  MOZ_LOG(gWindowsLog, LogLevel::Info, ("\n"));
+#endif
+}
+
+/**************************************************************
+ *
+ * SECTION: OnXXX message handlers
+ *
+ * For message handlers that need to be broken out or
+ * implemented in specific platform code.
+ *
+ **************************************************************/
+
+void nsWindow::OnWindowPosChanged(WINDOWPOS* wp) {
+  if (!wp) {
+    return;
+  }
+
+  MaybeLogPosChanged(mWnd, wp);
+
+  // Handle window size mode changes
+  if (wp->flags & SWP_FRAMECHANGED) {
+    // Bug 566135 - Windows theme code calls show window on SW_SHOWMINIMIZED
+    // windows when fullscreen games disable desktop composition. If we're
+    // minimized and not being activated, ignore the event and let windows
+    // handle it.
+    if (mFrameState->GetSizeMode() == nsSizeMode_Minimized &&
+        (wp->flags & SWP_NOACTIVATE)) {
+      return;
+    }
+
+    mFrameState->OnFrameChanged();
+
+    if (mFrameState->GetSizeMode() == nsSizeMode_Minimized) {
+      // Skip window size change events below on minimization.
+      return;
+    }
+  }
+
+  // Notify visibility change when window is activated.
+  if (!(wp->flags & SWP_NOACTIVATE) && NeedsToTrackWindowOcclusionState()) {
+    WinWindowOcclusionTracker::Get()->OnWindowVisibilityChanged(
+        this, mFrameState->GetSizeMode() != nsSizeMode_Minimized);
+  }
+
+  // Handle window position changes
+  if (!(wp->flags & SWP_NOMOVE)) {
+    mBounds.MoveTo(wp->x, wp->y);
+    NotifyWindowMoved(wp->x, wp->y);
+  }
+
+  // Handle window size changes
+  if (!(wp->flags & SWP_NOSIZE)) {
+    RECT r;
+    int32_t newWidth, newHeight;
+
+    ::GetWindowRect(mWnd, &r);
+
+    newWidth = r.right - r.left;
+    newHeight = r.bottom - r.top;
+
+    if (newWidth > mLastSize.width) {
+      RECT drect;
+
+      // getting wider
+      drect.left = wp->x + mLastSize.width;
+      drect.top = wp->y;
+      drect.right = drect.left + (newWidth - mLastSize.width);
+      drect.bottom = drect.top + newHeight;
+
+      ::RedrawWindow(mWnd, &drect, nullptr,
+                     RDW_INVALIDATE | RDW_NOERASE | RDW_NOINTERNALPAINT |
+                         RDW_ERASENOW | RDW_ALLCHILDREN);
+    }
+    if (newHeight > mLastSize.height) {
+      RECT drect;
+
+      // getting taller
+      drect.left = wp->x;
+      drect.top = wp->y + mLastSize.height;
+      drect.right = drect.left + newWidth;
+      drect.bottom = drect.top + (newHeight - mLastSize.height);
+
+      ::RedrawWindow(mWnd, &drect, nullptr,
+                     RDW_INVALIDATE | RDW_NOERASE | RDW_NOINTERNALPAINT |
+                         RDW_ERASENOW | RDW_ALLCHILDREN);
+    }
+
+    mBounds.SizeTo(newWidth, newHeight);
+    mLastSize.width = newWidth;
+    mLastSize.height = newHeight;
+
+#ifdef WINSTATE_DEBUG_OUTPUT
+    MOZ_LOG(gWindowsLog, LogLevel::Info,
+            ("*** Resize window: %d x %d x %d x %d\n", wp->x, wp->y, newWidth,
+             newHeight));
+#endif
+
+    if (mAspectRatio > 0) {
+      // It's possible (via Windows Aero Snap) that the size of the window
+      // has changed such that it violates the aspect ratio constraint. If so,
+      // queue up an event to enforce the aspect ratio constraint and repaint.
+      // When resized with Windows Aero Snap, we are in the NOT_RESIZING state.
+      float newAspectRatio = (float)newWidth / newHeight;
+      if (mResizeState == NOT_RESIZING && mAspectRatio != newAspectRatio) {
+        // Hold a reference to self alive and pass it into the lambda to make
+        // sure this nsIWidget stays alive long enough to run this function.
+        nsCOMPtr<nsIWidget> self(this);
+        NS_DispatchToMainThread(NS_NewRunnableFunction(
+            "EnforceAspectRatio", [self, this, newWidth]() -> void {
+              if (mWnd) {
+                Resize(newWidth, newWidth / mAspectRatio, true);
+              }
+            }));
+      }
+    }
+
+    // If a maximized window is resized, recalculate the non-client margins.
+    if (mFrameState->GetSizeMode() == nsSizeMode_Maximized) {
+      if (UpdateNonClientMargins(true)) {
+        // gecko resize event already sent by UpdateNonClientMargins.
+        return;
+      }
+    }
+  }
+
+  // Notify the widget listener for size change of client area for gecko
+  // events. This needs to be done when either window size is changed,
+  // or window frame is changed. They may not happen together.
+  // However, we don't invoke that for popup when window frame changes,
+  // because popups may trigger frame change before size change via
+  // {Set,Clear}ThemeRegion they invoke in Resize. That would make the
+  // code below call OnResize with a wrong client size first, which can
+  // lead to flickerling for some popups.
+  if (!(wp->flags & SWP_NOSIZE) ||
+      ((wp->flags & SWP_FRAMECHANGED) && !IsPopup())) {
+    RECT r;
+    LayoutDeviceIntSize clientSize;
+    if (::GetClientRect(mWnd, &r)) {
+      clientSize = WinUtils::ToIntRect(r).Size();
+    } else {
+      clientSize = mBounds.Size();
+    }
+    // Send a gecko resize event
+    OnResize(clientSize);
+  }
+}
+
+void nsWindow::OnWindowPosChanging(WINDOWPOS* info) {
+  // Update non-client margins if the frame size is changing, and let the
+  // browser know we are changing size modes, so alternative css can kick in.
+  // If we're going into fullscreen mode, ignore this, since it'll reset
+  // margins to normal mode.
+  if (info->flags & SWP_FRAMECHANGED && !(info->flags & SWP_NOSIZE)) {
+    mFrameState->OnFrameChanging();
+  }
+
+  // Force fullscreen. This works around a bug in Windows 10 1809 where
+  // using fullscreen when a window is "snapped" causes a spurious resize
+  // smaller than the full screen, see bug 1482920.
+  if (mFrameState->GetSizeMode() == nsSizeMode_Fullscreen &&
+      !(info->flags & SWP_NOMOVE) && !(info->flags & SWP_NOSIZE)) {
+    nsCOMPtr<nsIScreenManager> screenmgr =
+        do_GetService(sScreenManagerContractID);
+    if (screenmgr) {
+      LayoutDeviceIntRect bounds(info->x, info->y, info->cx, info->cy);
+      DesktopIntRect deskBounds =
+          RoundedToInt(bounds / GetDesktopToDeviceScale());
+      nsCOMPtr<nsIScreen> screen;
+      screenmgr->ScreenForRect(deskBounds.X(), deskBounds.Y(),
+                               deskBounds.Width(), deskBounds.Height(),
+                               getter_AddRefs(screen));
+
+      if (screen) {
+        auto rect = screen->GetRect();
+        info->x = rect.x;
+        info->y = rect.y;
+        info->cx = rect.width;
+        info->cy = rect.height;
+      }
+    }
+  }
+
+  // enforce local z-order rules
+  if (!(info->flags & SWP_NOZORDER)) {
+    HWND hwndAfter = info->hwndInsertAfter;
+
+    nsWindow* aboveWindow = 0;
+    nsWindowZ placement;
+
+    if (hwndAfter == HWND_BOTTOM)
+      placement = nsWindowZBottom;
+    else if (hwndAfter == HWND_TOP || hwndAfter == HWND_TOPMOST ||
+             hwndAfter == HWND_NOTOPMOST)
+      placement = nsWindowZTop;
+    else {
+      placement = nsWindowZRelative;
+      aboveWindow = WinUtils::GetNSWindowPtr(hwndAfter);
+    }
+
+    if (mWidgetListener) {
+      nsCOMPtr<nsIWidget> actualBelow = nullptr;
+      if (mWidgetListener->ZLevelChanged(false, &placement, aboveWindow,
+                                         getter_AddRefs(actualBelow))) {
+        if (placement == nsWindowZBottom)
+          info->hwndInsertAfter = HWND_BOTTOM;
+        else if (placement == nsWindowZTop)
+          info->hwndInsertAfter = HWND_TOP;
+        else {
+          info->hwndInsertAfter =
+              (HWND)actualBelow->GetNativeData(NS_NATIVE_WINDOW);
+        }
+      }
+    }
+  }
+  // prevent rude external programs from making hidden window visible
+  if (mWindowType == WindowType::Invisible) info->flags &= ~SWP_SHOWWINDOW;
+
+  // When waking from sleep or switching out of tablet mode, Windows 10
+  // Version 1809 will reopen popup windows that should be hidden. Detect
+  // this case and refuse to show the window.
+  static bool sDWMUnhidesPopups = IsWin10Sep2018UpdateOrLater();
+  if (sDWMUnhidesPopups && (info->flags & SWP_SHOWWINDOW) &&
+      mWindowType == WindowType::Popup && mWidgetListener &&
+      mWidgetListener->ShouldNotBeVisible()) {
+    info->flags &= ~SWP_SHOWWINDOW;
+  }
+}
+
+void nsWindow::UserActivity() {
+  // Check if we have the idle service, if not we try to get it.
+  if (!mIdleService) {
+    mIdleService = do_GetService("@mozilla.org/widget/useridleservice;1");
+  }
+
+  // Check that we now have the idle service.
+  if (mIdleService) {
+    mIdleService->ResetIdleTimeOut(0);
+  }
+}
+
+// Helper function for TouchDeviceNeedsPanGestureConversion(PTOUCHINPUT,
+// uint32_t).
+static bool TouchDeviceNeedsPanGestureConversion(HANDLE aSource) {
+  std::string deviceName;
+  UINT dataSize = 0;
+  // The first call just queries how long the name string will be.
+  GetRawInputDeviceInfoA(aSource, RIDI_DEVICENAME, nullptr, &dataSize);
+  if (!dataSize || dataSize > 0x10000) {
+    return false;
+  }
+  deviceName.resize(dataSize);
+  // The second call actually populates the string.
+  UINT result = GetRawInputDeviceInfoA(aSource, RIDI_DEVICENAME, &deviceName[0],
+                                       &dataSize);
+  if (result == UINT_MAX) {
+    return false;
+  }
+  // The affected device name is "\\?\VIRTUAL_DIGITIZER", but each backslash
+  // needs to be escaped with another one.
+  std::string expectedDeviceName = "\\\\?\\VIRTUAL_DIGITIZER";
+  // For some reason, the dataSize returned by the first call is double the
+  // actual length of the device name (as if it were returning the size of a
+  // wide-character string in bytes) even though we are using the narrow
+  // version of the API. For the comparison against the expected device name
+  // to pass, we truncate the buffer to be no longer tha the expected device
+  // name.
+  if (deviceName.substr(0, expectedDeviceName.length()) != expectedDeviceName) {
+    return false;
+  }
+
+  RID_DEVICE_INFO deviceInfo;
+  deviceInfo.cbSize = sizeof(deviceInfo);
+  dataSize = sizeof(deviceInfo);
+  result =
+      GetRawInputDeviceInfoA(aSource, RIDI_DEVICEINFO, &deviceInfo, &dataSize);
+  if (result == UINT_MAX) {
+    return false;
+  }
+  // The device identifiers that we check for here come from bug 1355162
+  // comment 1 (see also bug 1511901 comment 35).
+  return deviceInfo.dwType == RIM_TYPEHID && deviceInfo.hid.dwVendorId == 0 &&
+         deviceInfo.hid.dwProductId == 0 &&
+         deviceInfo.hid.dwVersionNumber == 1 &&
+         deviceInfo.hid.usUsagePage == 13 && deviceInfo.hid.usUsage == 4;
+}
+
+// Determine if the touch device that originated |aOSEvent| needs to have
+// touch events representing a two-finger gesture converted to pan
+// gesture events.
+// We only do this for touch devices with a specific name and identifiers.
+static bool TouchDeviceNeedsPanGestureConversion(PTOUCHINPUT aOSEvent,
+                                                 uint32_t aTouchCount) {
+  if (!StaticPrefs::apz_windows_check_for_pan_gesture_conversion()) {
+    return false;
+  }
+  if (aTouchCount == 0) {
+    return false;
+  }
+  HANDLE source = aOSEvent[0].hSource;
+
+  // Cache the result of this computation for each touch device.
+  // Touch devices are identified by the HANDLE stored in the hSource
+  // field of TOUCHINPUT.
+  static std::map<HANDLE, bool> sResultCache;
+  auto [iter, inserted] = sResultCache.emplace(source, false);
+  if (inserted) {
+    iter->second = TouchDeviceNeedsPanGestureConversion(source);
+  }
+  return iter->second;
+}
+
+Maybe<PanGestureInput> nsWindow::ConvertTouchToPanGesture(
+    const MultiTouchInput& aTouchInput, PTOUCHINPUT aOSEvent) {
+  // Checks if the touch device that originated the touch event is one
+  // for which we want to convert the touch events to pang gesture events.
+  bool shouldConvert = TouchDeviceNeedsPanGestureConversion(
+      aOSEvent, aTouchInput.mTouches.Length());
+  if (!shouldConvert) {
+    return Nothing();
+  }
+
+  // Only two-finger gestures need conversion.
+  if (aTouchInput.mTouches.Length() != 2) {
+    return Nothing();
+  }
+
+  PanGestureInput::PanGestureType eventType = PanGestureInput::PANGESTURE_PAN;
+  if (aTouchInput.mType == MultiTouchInput::MULTITOUCH_START) {
+    eventType = PanGestureInput::PANGESTURE_START;
+  } else if (aTouchInput.mType == MultiTouchInput::MULTITOUCH_END) {
+    eventType = PanGestureInput::PANGESTURE_END;
+  } else if (aTouchInput.mType == MultiTouchInput::MULTITOUCH_CANCEL) {
+    eventType = PanGestureInput::PANGESTURE_CANCELLED;
+  }
+
+  // Use the midpoint of the two touches as the start point of the pan gesture.
+  ScreenPoint focusPoint = (aTouchInput.mTouches[0].mScreenPoint +
+                            aTouchInput.mTouches[1].mScreenPoint) /
+                           2;
+  // To compute the displacement of the pan gesture, we keep track of the
+  // location of the previous event.
+  ScreenPoint displacement = (eventType == PanGestureInput::PANGESTURE_START)
+                                 ? ScreenPoint(0, 0)
+                                 : (focusPoint - mLastPanGestureFocus);
+  mLastPanGestureFocus = focusPoint;
+
+  // We need to negate the displacement because for a touch event, moving the
+  // fingers down results in scrolling up, but for a touchpad gesture, we want
+  // moving the fingers down to result in scrolling down.
+  PanGestureInput result(eventType, aTouchInput.mTimeStamp, focusPoint,
+                         -displacement, aTouchInput.modifiers);
+  result.mSimulateMomentum = true;
+
+  return Some(result);
+}
+
+// Dispatch an event that originated as an OS touch event.
+// Usually, we want to dispatch it as a touch event, but some touchpads
+// produce touch events for two-finger scrolling, which need to be converted
+// to pan gesture events for correct behaviour.
+void nsWindow::DispatchTouchOrPanGestureInput(MultiTouchInput& aTouchInput,
+                                              PTOUCHINPUT aOSEvent) {
+  if (Maybe<PanGestureInput> panInput =
+          ConvertTouchToPanGesture(aTouchInput, aOSEvent)) {
+    DispatchPanGestureInput(*panInput);
+    return;
+  }
+
+  DispatchTouchInput(aTouchInput);
+}
+
+bool nsWindow::OnTouch(WPARAM wParam, LPARAM lParam) {
+  uint32_t cInputs = LOWORD(wParam);
+  PTOUCHINPUT pInputs = new TOUCHINPUT[cInputs];
+
+  if (GetTouchInputInfo((HTOUCHINPUT)lParam, cInputs, pInputs,
+                        sizeof(TOUCHINPUT))) {
+    MultiTouchInput touchInput, touchEndInput;
+
+    // Walk across the touch point array processing each contact point.
+    for (uint32_t i = 0; i < cInputs; i++) {
+      bool addToEvent = false, addToEndEvent = false;
+
+      // N.B.: According with MS documentation
+      // https://msdn.microsoft.com/en-us/library/windows/desktop/dd317334(v=vs.85).aspx
+      // TOUCHEVENTF_DOWN cannot be combined with TOUCHEVENTF_MOVE or
+      // TOUCHEVENTF_UP.  Possibly, it means that TOUCHEVENTF_MOVE and
+      // TOUCHEVENTF_UP can be combined together.
+
+      if (pInputs[i].dwFlags & (TOUCHEVENTF_DOWN | TOUCHEVENTF_MOVE)) {
+        if (touchInput.mTimeStamp.IsNull()) {
+          // Initialize a touch event to send.
+          touchInput.mType = MultiTouchInput::MULTITOUCH_MOVE;
+          touchInput.mTimeStamp = GetMessageTimeStamp(::GetMessageTime());
+          ModifierKeyState modifierKeyState;
+          touchInput.modifiers = modifierKeyState.GetModifiers();
+        }
+        // Pres shell expects this event to be a eTouchStart
+        // if any new contact points have been added since the last event sent.
+        if (pInputs[i].dwFlags & TOUCHEVENTF_DOWN) {
+          touchInput.mType = MultiTouchInput::MULTITOUCH_START;
+        }
+        addToEvent = true;
+      }
+      if (pInputs[i].dwFlags & TOUCHEVENTF_UP) {
+        // Pres shell expects removed contacts points to be delivered in a
+        // separate eTouchEnd event containing only the contact points that were
+        // removed.
+        if (touchEndInput.mTimeStamp.IsNull()) {
+          // Initialize a touch event to send.
+          touchEndInput.mType = MultiTouchInput::MULTITOUCH_END;
+          touchEndInput.mTimeStamp = GetMessageTimeStamp(::GetMessageTime());
+          ModifierKeyState modifierKeyState;
+          touchEndInput.modifiers = modifierKeyState.GetModifiers();
+        }
+        addToEndEvent = true;
+      }
+      if (!addToEvent && !addToEndEvent) {
+        // Filter out spurious Windows events we don't understand, like palm
+        // contact.
+        continue;
+      }
+
+      // Setup the touch point we'll append to the touch event array.
+      nsPointWin touchPoint;
+      touchPoint.x = TOUCH_COORD_TO_PIXEL(pInputs[i].x);
+      touchPoint.y = TOUCH_COORD_TO_PIXEL(pInputs[i].y);
+      touchPoint.ScreenToClient(mWnd);
+
+      // Initialize the touch data.
+      SingleTouchData touchData(
+          pInputs[i].dwID,                               // aIdentifier
+          ScreenIntPoint::FromUnknownPoint(touchPoint),  // aScreenPoint
+          // The contact area info cannot be trusted even when
+          // TOUCHINPUTMASKF_CONTACTAREA is set when the input source is pen,
+          // which somehow violates the API docs. (bug 1710509) Ultimately the
+          // dwFlags check will become redundant since we want to migrate to
+          // WM_POINTER for pens. (bug 1707075)
+          (pInputs[i].dwMask & TOUCHINPUTMASKF_CONTACTAREA) &&
+                  !(pInputs[i].dwFlags & TOUCHEVENTF_PEN)
+              ? ScreenSize(TOUCH_COORD_TO_PIXEL(pInputs[i].cxContact) / 2,
+                           TOUCH_COORD_TO_PIXEL(pInputs[i].cyContact) / 2)
+              : ScreenSize(1, 1),  // aRadius
+          0.0f,                    // aRotationAngle
+          0.0f);                   // aForce
+
+      // Append touch data to the appropriate event.
+      if (addToEvent) {
+        touchInput.mTouches.AppendElement(touchData);
+      }
+      if (addToEndEvent) {
+        touchEndInput.mTouches.AppendElement(touchData);
+      }
+    }
+
+    // Dispatch touch start and touch move event if we have one.
+    if (!touchInput.mTimeStamp.IsNull()) {
+      DispatchTouchOrPanGestureInput(touchInput, pInputs);
+    }
+    // Dispatch touch end event if we have one.
+    if (!touchEndInput.mTimeStamp.IsNull()) {
+      DispatchTouchOrPanGestureInput(touchEndInput, pInputs);
+    }
+  }
+
+  delete[] pInputs;
+  CloseTouchInputHandle((HTOUCHINPUT)lParam);
+  return true;
+}
+
+// Gesture event processing. Handles WM_GESTURE events.
+bool nsWindow::OnGesture(WPARAM wParam, LPARAM lParam) {
+  // Treatment for pan events which translate into scroll events:
+  if (mGesture.IsPanEvent(lParam)) {
+    if (!mGesture.ProcessPanMessage(mWnd, wParam, lParam))
+      return false;  // ignore
+
+    nsEventStatus status;
+
+    WidgetWheelEvent wheelEvent(true, eWheel, this);
+
+    ModifierKeyState modifierKeyState;
+    modifierKeyState.InitInputEvent(wheelEvent);
+
+    wheelEvent.mButton = 0;
+    wheelEvent.mTimeStamp = GetMessageTimeStamp(::GetMessageTime());
+    wheelEvent.mInputSource = MouseEvent_Binding::MOZ_SOURCE_TOUCH;
+
+    bool endFeedback = true;
+
+    if (mGesture.PanDeltaToPixelScroll(wheelEvent)) {
+      DispatchEvent(&wheelEvent, status);
+    }
+
+    if (mDisplayPanFeedback) {
+      mGesture.UpdatePanFeedbackX(
+          mWnd, DeprecatedAbs(RoundDown(wheelEvent.mOverflowDeltaX)),
+          endFeedback);
+      mGesture.UpdatePanFeedbackY(
+          mWnd, DeprecatedAbs(RoundDown(wheelEvent.mOverflowDeltaY)),
+          endFeedback);
+      mGesture.PanFeedbackFinalize(mWnd, endFeedback);
+    }
+
+    CloseGestureInfoHandle((HGESTUREINFO)lParam);
+
+    return true;
+  }
+
+  // Other gestures translate into simple gesture events:
+  WidgetSimpleGestureEvent event(true, eVoidEvent, this);
+  if (!mGesture.ProcessGestureMessage(mWnd, wParam, lParam, event)) {
+    return false;  // fall through to DefWndProc
+  }
+
+  // Polish up and send off the new event
+  ModifierKeyState modifierKeyState;
+  modifierKeyState.InitInputEvent(event);
+  event.mButton = 0;
+  event.mTimeStamp = GetMessageTimeStamp(::GetMessageTime());
+  event.mInputSource = MouseEvent_Binding::MOZ_SOURCE_TOUCH;
+
+  nsEventStatus status;
+  DispatchEvent(&event, status);
+  if (status == nsEventStatus_eIgnore) {
+    return false;  // Ignored, fall through
+  }
+
+  // Only close this if we process and return true.
+  CloseGestureInfoHandle((HGESTUREINFO)lParam);
+
+  return true;  // Handled
+}
+
+// WM_DESTROY event handler
+void nsWindow::OnDestroy() {
+  mOnDestroyCalled = true;
+
+  // If this is a toplevel window, notify the taskbar concealer to clean up any
+  // relevant state.
+  if (!mParent) {
+    TaskbarConcealer::OnWindowDestroyed(mWnd);
+  }
+
+  // Make sure we don't get destroyed in the process of tearing down.
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
+
+  // Dispatch the destroy notification.
+  if (!mInDtor) NotifyWindowDestroyed();
+
+  // Prevent the widget from sending additional events.
+  mWidgetListener = nullptr;
+  mAttachedWidgetListener = nullptr;
+
+  DestroyDirectManipulation();
+
+  if (mWnd == mLastKillFocusWindow) {
+    mLastKillFocusWindow = nullptr;
+  }
+  // Unregister notifications from terminal services
+  ::WTSUnRegisterSessionNotification(mWnd);
+
+  // We will stop receiving native events after dissociating from our native
+  // window. We will also disappear from the output of WinUtils::GetNSWindowPtr
+  // for that window.
+  DissociateFromNativeWindow();
+
+  // Once mWidgetListener is cleared and the subclass is reset, sCurrentWindow
+  // can be cleared. (It's used in tracking windows for mouse events.)
+  if (sCurrentWindow == this) sCurrentWindow = nullptr;
+
+  // Disconnects us from our parent, will call our GetParent().
+  nsBaseWidget::Destroy();
+
+  // Release references to children, device context, toolkit, and app shell.
+  nsBaseWidget::OnDestroy();
+
+  // Clear our native parent handle.
+  // XXX Windows will take care of this in the proper order, and
+  // SetParent(nullptr)'s remove child on the parent already took place in
+  // nsBaseWidget's Destroy call above.
+  // SetParent(nullptr);
+  mParent = nullptr;
+
+  // We have to destroy the native drag target before we null out our window
+  // pointer.
+  EnableDragDrop(false);
+
+  // If we're going away and for some reason we're still the rollup widget,
+  // rollup and turn off capture.
+  nsIRollupListener* rollupListener = nsBaseWidget::GetActiveRollupListener();
+  nsCOMPtr<nsIWidget> rollupWidget;
+  if (rollupListener) {
+    rollupWidget = rollupListener->GetRollupWidget();
+  }
+  if (this == rollupWidget) {
+    rollupListener->Rollup({});
+    CaptureRollupEvents(false);
+  }
+
+  IMEHandler::OnDestroyWindow(this);
+
+  // Free GDI window class objects
+  if (mBrush) {
+    VERIFY(::DeleteObject(mBrush));
+    mBrush = nullptr;
+  }
+
+  // Destroy any custom cursor resources.
+  if (mCursor.IsCustom()) {
+    SetCursor(Cursor{eCursor_standard});
+  }
+
+  if (mCompositorWidgetDelegate) {
+    mCompositorWidgetDelegate->OnDestroyWindow();
+  }
+  mBasicLayersSurface = nullptr;
+
+  // Finalize panning feedback to possibly restore window displacement
+  mGesture.PanFeedbackFinalize(mWnd, true);
+
+  // Clear the main HWND.
+  mWnd = nullptr;
+}
+
+// Send a resize message to the listener
+bool nsWindow::OnResize(const LayoutDeviceIntSize& aSize) {
+  if (mCompositorWidgetDelegate &&
+      !mCompositorWidgetDelegate->OnWindowResize(aSize)) {
+    return false;
+  }
+
+  bool result = false;
+  if (mWidgetListener) {
+    result = mWidgetListener->WindowResized(this, aSize.width, aSize.height);
+  }
+
+  // If there is an attached view, inform it as well as the normal widget
+  // listener.
+  if (mAttachedWidgetListener) {
+    return mAttachedWidgetListener->WindowResized(this, aSize.width,
+                                                  aSize.height);
+  }
+
+  return result;
+}
+
+void nsWindow::OnSizeModeChange() {
+  const nsSizeMode mode = mFrameState->GetSizeMode();
+
+  MOZ_LOG(gWindowsLog, LogLevel::Info,
+          ("nsWindow::OnSizeModeChange() sizeMode %d", mode));
+
+  if (NeedsToTrackWindowOcclusionState()) {
+    WinWindowOcclusionTracker::Get()->OnWindowVisibilityChanged(
+        this, mode != nsSizeMode_Minimized);
+
+    wr::DebugFlags flags{0};
+    flags._0 = gfx::gfxVars::WebRenderDebugFlags();
+    bool debugEnabled = bool(flags & wr::DebugFlags::WINDOW_VISIBILITY_DBG);
+    if (debugEnabled && mCompositorWidgetDelegate) {
+      mCompositorWidgetDelegate->NotifyVisibilityUpdated(mode,
+                                                         mIsFullyOccluded);
+    }
+  }
+
+  if (mCompositorWidgetDelegate) {
+    mCompositorWidgetDelegate->OnWindowModeChange(mode);
+  }
+
+  if (mWidgetListener) {
+    mWidgetListener->SizeModeChanged(mode);
+  }
+}
+
+bool nsWindow::OnHotKey(WPARAM wParam, LPARAM lParam) { return true; }
+
+bool nsWindow::IsPopup() { return mWindowType == WindowType::Popup; }
+
+bool nsWindow::ShouldUseOffMainThreadCompositing() {
+  if (mWindowType == WindowType::Popup && mPopupType == PopupType::Tooltip) {
+    return false;
+  }
+
+  // Content rendering of popup is always done by child window.
+  // See nsDocumentViewer::ShouldAttachToTopLevel().
+  if (mWindowType == WindowType::Popup && !mIsChildWindow) {
+    MOZ_ASSERT(!mParent);
+    return false;
+  }
+
+  return nsBaseWidget::ShouldUseOffMainThreadCompositing();
+}
+
+void nsWindow::WindowUsesOMTC() {
+  ULONG_PTR style = ::GetClassLongPtr(mWnd, GCL_STYLE);
+  if (!style) {
+    NS_WARNING("Could not get window class style");
+    return;
+  }
+  style |= CS_HREDRAW | CS_VREDRAW;
+  DebugOnly<ULONG_PTR> result = ::SetClassLongPtr(mWnd, GCL_STYLE, style);
+  NS_WARNING_ASSERTION(result, "Could not reset window class style");
+}
+
+void nsWindow::OnDPIChanged(int32_t x, int32_t y, int32_t width,
+                            int32_t height) {
+  // Don't try to handle WM_DPICHANGED for popup windows (see bug 1239353);
+  // they remain tied to their original parent's resolution.
+  if (mWindowType == WindowType::Popup) {
+    return;
+  }
+  if (StaticPrefs::layout_css_devPixelsPerPx() > 0.0) {
+    return;
+  }
+  mDefaultScale = -1.0;  // force recomputation of scale factor
+
+  if (mResizeState != RESIZING &&
+      mFrameState->GetSizeMode() == nsSizeMode_Normal) {
+    // Limit the position (if not in the middle of a drag-move) & size,
+    // if it would overflow the destination screen
+    nsCOMPtr<nsIScreenManager> sm = do_GetService(sScreenManagerContractID);
+    if (sm) {
+      nsCOMPtr<nsIScreen> screen;
+      sm->ScreenForRect(x, y, width, height, getter_AddRefs(screen));
+      if (screen) {
+        int32_t availLeft, availTop, availWidth, availHeight;
+        screen->GetAvailRect(&availLeft, &availTop, &availWidth, &availHeight);
+        if (mResizeState != MOVING) {
+          x = std::max(x, availLeft);
+          y = std::max(y, availTop);
+        }
+        width = std::min(width, availWidth);
+        height = std::min(height, availHeight);
+      }
+    }
+
+    Resize(x, y, width, height, true);
+  }
+  UpdateNonClientMargins();
+  ChangedDPI();
+  ResetLayout();
+}
+
+// Callback to generate OnCloakChanged pseudo-events.
+/* static */
+void nsWindow::OnCloakEvent(HWND aWnd, bool aCloaked) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  const char* const kEventName = aCloaked ? "CLOAKED" : "UNCLOAKED";
+  nsWindow* pWin = WinUtils::GetNSWindowPtr(aWnd);
+  if (!pWin) {
+    MOZ_LOG(
+        sCloakingLog, LogLevel::Debug,
+        ("Received %s event for HWND %p (not an nsWindow)", kEventName, aWnd));
+    return;
+  }
+
+  const char* const kWasCloakedStr = pWin->mIsCloaked ? "cloaked" : "uncloaked";
+  if (mozilla::IsCloaked(aWnd) == pWin->mIsCloaked) {
+    MOZ_LOG(sCloakingLog, LogLevel::Debug,
+            ("Received redundant %s event for %s HWND %p; discarding",
+             kEventName, kWasCloakedStr, aWnd));
+    return;
+  }
+
+  MOZ_LOG(
+      sCloakingLog, LogLevel::Info,
+      ("Received %s event for %s HWND %p", kEventName, kWasCloakedStr, aWnd));
+
+  // Cloaking events like the one we've just received are sent asynchronously.
+  // Rather than process them one-by-one, we jump the gun a bit and perform
+  // updates on all newly cloaked/uncloaked nsWindows at once. This also lets us
+  // batch operations that consider more than one window's state.
+  struct Item {
+    nsWindow* win;
+    bool nowCloaked;
+  };
+  nsTArray<Item> changedWindows;
+
+  mozilla::EnumerateThreadWindows([&](HWND hwnd) {
+    nsWindow* pWin = WinUtils::GetNSWindowPtr(hwnd);
+    if (!pWin) {
+      return;
+    }
+
+    const bool isCloaked = mozilla::IsCloaked(hwnd);
+    if (isCloaked != pWin->mIsCloaked) {
+      changedWindows.AppendElement(Item{pWin, isCloaked});
+    }
+  });
+
+  if (changedWindows.IsEmpty()) {
+    return;
+  }
+
+  for (const Item& item : changedWindows) {
+    item.win->OnCloakChanged(item.nowCloaked);
+  }
+
+  nsWindow::TaskbarConcealer::OnCloakChanged();
+}
+
+void nsWindow::OnCloakChanged(bool aCloaked) {
+  MOZ_LOG(sCloakingLog, LogLevel::Info,
+          ("Calling OnCloakChanged(): HWND %p, aCloaked %s", mWnd,
+           aCloaked ? "true" : "false"));
+  mIsCloaked = aCloaked;
+}
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: IME management and accessibility
+ **
+ ** Handles managing IME input and accessibility.
+ **
+ **************************************************************
+ **************************************************************/
+
+void nsWindow::SetInputContext(const InputContext& aContext,
+                               const InputContextAction& aAction) {
+  InputContext newInputContext = aContext;
+  IMEHandler::SetInputContext(this, newInputContext, aAction);
+  mInputContext = newInputContext;
+}
+
+InputContext nsWindow::GetInputContext() {
+  mInputContext.mIMEState.mOpen = IMEState::CLOSED;
+  if (WinUtils::IsIMEEnabled(mInputContext) && IMEHandler::GetOpenState(this)) {
+    mInputContext.mIMEState.mOpen = IMEState::OPEN;
+  } else {
+    mInputContext.mIMEState.mOpen = IMEState::CLOSED;
+  }
+  return mInputContext;
+}
+
+TextEventDispatcherListener* nsWindow::GetNativeTextEventDispatcherListener() {
+  return IMEHandler::GetNativeTextEventDispatcherListener();
+}
+
+#ifdef ACCESSIBILITY
+#  ifdef DEBUG
+#    define NS_LOG_WMGETOBJECT(aWnd, aHwnd, aAcc)                            \
+      if (a11y::logging::IsEnabled(a11y::logging::ePlatforms)) {             \
+        printf(                                                              \
+            "Get the window:\n  {\n     HWND: %p, parent HWND: %p, wndobj: " \
+            "%p,\n",                                                         \
+            aHwnd, ::GetParent(aHwnd), aWnd);                                \
+        printf("     acc: %p", aAcc);                                        \
+        if (aAcc) {                                                          \
+          nsAutoString name;                                                 \
+          aAcc->Name(name);                                                  \
+          printf(", accname: %s", NS_ConvertUTF16toUTF8(name).get());        \
+        }                                                                    \
+        printf("\n }\n");                                                    \
+      }
+
+#  else
+#    define NS_LOG_WMGETOBJECT(aWnd, aHwnd, aAcc)
+#  endif
+
+a11y::LocalAccessible* nsWindow::GetAccessible() {
+  // If the pref was ePlatformIsDisabled, return null here, disabling a11y.
+  if (a11y::PlatformDisabledState() == a11y::ePlatformIsDisabled)
+    return nullptr;
+
+  if (mInDtor || mOnDestroyCalled || mWindowType == WindowType::Invisible) {
+    return nullptr;
+  }
+
+  // In case of popup window return a popup accessible.
+  nsView* view = nsView::GetViewFor(this);
+  if (view) {
+    nsIFrame* frame = view->GetFrame();
+    if (frame && nsLayoutUtils::IsPopup(frame)) {
+      nsAccessibilityService* accService = GetOrCreateAccService();
+      if (accService) {
+        a11y::DocAccessible* docAcc =
+            GetAccService()->GetDocAccessible(frame->PresShell());
+        if (docAcc) {
+          NS_LOG_WMGETOBJECT(
+              this, mWnd,
+              docAcc->GetAccessibleOrDescendant(frame->GetContent()));
+          return docAcc->GetAccessibleOrDescendant(frame->GetContent());
+        }
+      }
+    }
+  }
+
+  // otherwise root document accessible.
+  NS_LOG_WMGETOBJECT(this, mWnd, GetRootAccessible());
+  return GetRootAccessible();
+}
+#endif
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: Transparency
+ **
+ ** Window transparency helpers.
+ **
+ **************************************************************
+ **************************************************************/
+
+void nsWindow::SetWindowTranslucencyInner(TransparencyMode aMode) {
+  if (aMode == mTransparencyMode) return;
+
+  // stop on dialogs and popups!
+  HWND hWnd = WinUtils::GetTopLevelHWND(mWnd, true);
+  nsWindow* parent = WinUtils::GetNSWindowPtr(hWnd);
+
+  if (!parent) {
+    NS_WARNING("Trying to use transparent chrome in an embedded context");
+    return;
+  }
+
+  if (parent != this) {
+    NS_WARNING(
+        "Setting SetWindowTranslucencyInner on a parent this is not us!");
+  }
+
+  if (aMode == TransparencyMode::Transparent) {
+    // If we're switching to the use of a transparent window, hide the chrome
+    // on our parent.
+    HideWindowChrome(true);
+  } else if (mHideChrome &&
+             mTransparencyMode == TransparencyMode::Transparent) {
+    // if we're switching out of transparent, re-enable our parent's chrome.
+    HideWindowChrome(false);
+  }
+
+  LONG_PTR style = ::GetWindowLongPtrW(hWnd, GWL_STYLE),
+           exStyle = ::GetWindowLongPtr(hWnd, GWL_EXSTYLE);
+
+  if (parent->mIsVisible) {
+    style |= WS_VISIBLE;
+    if (parent->mFrameState->GetSizeMode() == nsSizeMode_Maximized) {
+      style |= WS_MAXIMIZE;
+    } else if (parent->mFrameState->GetSizeMode() == nsSizeMode_Minimized) {
+      style |= WS_MINIMIZE;
+    }
+  }
+
+  if (aMode == TransparencyMode::Transparent)
+    exStyle |= WS_EX_LAYERED;
+  else
+    exStyle &= ~WS_EX_LAYERED;
+
+  VERIFY_WINDOW_STYLE(style);
+  ::SetWindowLongPtrW(hWnd, GWL_STYLE, style);
+  ::SetWindowLongPtrW(hWnd, GWL_EXSTYLE, exStyle);
+
+  mTransparencyMode = aMode;
+
+  if (mCompositorWidgetDelegate) {
+    mCompositorWidgetDelegate->UpdateTransparency(aMode);
+  }
+}
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: Popup rollup hooks
+ **
+ ** Deals with CaptureRollup on popup windows.
+ **
+ **************************************************************
+ **************************************************************/
+
+// Schedules a timer for a window, so we can rollup after processing the hook
+// event
+void nsWindow::ScheduleHookTimer(HWND aWnd, UINT aMsgId) {
+  // In some cases multiple hooks may be scheduled
+  // so ignore any other requests once one timer is scheduled
+  if (sHookTimerId == 0) {
+    // Remember the window handle and the message ID to be used later
+    sRollupMsgId = aMsgId;
+    sRollupMsgWnd = aWnd;
+    // Schedule native timer for doing the rollup after
+    // this event is done being processed
+    sHookTimerId = ::SetTimer(nullptr, 0, 0, (TIMERPROC)HookTimerForPopups);
+    NS_ASSERTION(sHookTimerId, "Timer couldn't be created.");
+  }
+}
+
+#ifdef POPUP_ROLLUP_DEBUG_OUTPUT
+int gLastMsgCode = 0;
+extern MSGFEventMsgInfo gMSGFEvents[];
+#endif
+
+// Process Menu messages, rollup when popup is clicked.
+LRESULT CALLBACK nsWindow::MozSpecialMsgFilter(int code, WPARAM wParam,
+                                               LPARAM lParam) {
+#ifdef POPUP_ROLLUP_DEBUG_OUTPUT
+  if (sProcessHook) {
+    MSG* pMsg = (MSG*)lParam;
+
+    int inx = 0;
+    while (gMSGFEvents[inx].mId != code && gMSGFEvents[inx].mStr != nullptr) {
+      inx++;
+    }
+    if (code != gLastMsgCode) {
+      if (gMSGFEvents[inx].mId == code) {
+#  ifdef DEBUG
+        MOZ_LOG(gWindowsLog, LogLevel::Info,
+                ("MozSpecialMessageProc - code: 0x%X  - %s  hw: %p\n", code,
+                 gMSGFEvents[inx].mStr, pMsg->hwnd));
+#  endif
+      } else {
+#  ifdef DEBUG
+        MOZ_LOG(gWindowsLog, LogLevel::Info,
+                ("MozSpecialMessageProc - code: 0x%X  - %d  hw: %p\n", code,
+                 gMSGFEvents[inx].mId, pMsg->hwnd));
+#  endif
+      }
+      gLastMsgCode = code;
+    }
+    PrintEvent(pMsg->message, FALSE, FALSE);
+  }
+#endif  // #ifdef POPUP_ROLLUP_DEBUG_OUTPUT
+
+  if (sProcessHook && code == MSGF_MENU) {
+    MSG* pMsg = (MSG*)lParam;
+    ScheduleHookTimer(pMsg->hwnd, pMsg->message);
+  }
+
+  return ::CallNextHookEx(sMsgFilterHook, code, wParam, lParam);
+}
+
+// Process all mouse messages. Roll up when a click is in a native window
+// that doesn't have an nsIWidget.
+LRESULT CALLBACK nsWindow::MozSpecialMouseProc(int code, WPARAM wParam,
+                                               LPARAM lParam) {
+  if (sProcessHook) {
+    switch (WinUtils::GetNativeMessage(wParam)) {
+      case WM_LBUTTONDOWN:
+      case WM_RBUTTONDOWN:
+      case WM_MBUTTONDOWN:
+      case WM_MOUSEWHEEL:
+      case WM_MOUSEHWHEEL: {
+        MOUSEHOOKSTRUCT* ms = (MOUSEHOOKSTRUCT*)lParam;
+        nsIWidget* mozWin = WinUtils::GetNSWindowPtr(ms->hwnd);
+        if (!mozWin) {
+          ScheduleHookTimer(ms->hwnd, (UINT)wParam);
+        }
+        break;
+      }
+    }
+  }
+  return ::CallNextHookEx(sCallMouseHook, code, wParam, lParam);
+}
+
+// Process all messages. Roll up when the window is moving, or
+// is resizing or when maximized or mininized.
+LRESULT CALLBACK nsWindow::MozSpecialWndProc(int code, WPARAM wParam,
+                                             LPARAM lParam) {
+#ifdef POPUP_ROLLUP_DEBUG_OUTPUT
+  if (sProcessHook) {
+    CWPSTRUCT* cwpt = (CWPSTRUCT*)lParam;
+    PrintEvent(cwpt->message, FALSE, FALSE);
+  }
+#endif
+
+  if (sProcessHook) {
+    CWPSTRUCT* cwpt = (CWPSTRUCT*)lParam;
+    if (cwpt->message == WM_MOVING || cwpt->message == WM_SIZING ||
+        cwpt->message == WM_GETMINMAXINFO) {
+      ScheduleHookTimer(cwpt->hwnd, (UINT)cwpt->message);
+    }
+  }
+
+  return ::CallNextHookEx(sCallProcHook, code, wParam, lParam);
+}
+
+// Register the special "hooks" for dropdown processing.
+void nsWindow::RegisterSpecialDropdownHooks() {
+  NS_ASSERTION(!sMsgFilterHook, "sMsgFilterHook must be NULL!");
+  NS_ASSERTION(!sCallProcHook, "sCallProcHook must be NULL!");
+
+  DISPLAY_NMM_PRT("***************** Installing Msg Hooks ***************\n");
+
+  // Install msg hook for moving the window and resizing
+  if (!sMsgFilterHook) {
+    DISPLAY_NMM_PRT("***** Hooking sMsgFilterHook!\n");
+    sMsgFilterHook = SetWindowsHookEx(WH_MSGFILTER, MozSpecialMsgFilter,
+                                      nullptr, GetCurrentThreadId());
+#ifdef POPUP_ROLLUP_DEBUG_OUTPUT
+    if (!sMsgFilterHook) {
+      MOZ_LOG(gWindowsLog, LogLevel::Info,
+              ("***** SetWindowsHookEx is NOT installed for WH_MSGFILTER!\n"));
+    }
+#endif
+  }
+
+  // Install msg hook for menus
+  if (!sCallProcHook) {
+    DISPLAY_NMM_PRT("***** Hooking sCallProcHook!\n");
+    sCallProcHook = SetWindowsHookEx(WH_CALLWNDPROC, MozSpecialWndProc, nullptr,
+                                     GetCurrentThreadId());
+#ifdef POPUP_ROLLUP_DEBUG_OUTPUT
+    if (!sCallProcHook) {
+      MOZ_LOG(
+          gWindowsLog, LogLevel::Info,
+          ("***** SetWindowsHookEx is NOT installed for WH_CALLWNDPROC!\n"));
+    }
+#endif
+  }
+
+  // Install msg hook for the mouse
+  if (!sCallMouseHook) {
+    DISPLAY_NMM_PRT("***** Hooking sCallMouseHook!\n");
+    sCallMouseHook = SetWindowsHookEx(WH_MOUSE, MozSpecialMouseProc, nullptr,
+                                      GetCurrentThreadId());
+#ifdef POPUP_ROLLUP_DEBUG_OUTPUT
+    if (!sCallMouseHook) {
+      MOZ_LOG(gWindowsLog, LogLevel::Info,
+              ("***** SetWindowsHookEx is NOT installed for WH_MOUSE!\n"));
+    }
+#endif
+  }
+}
+
+// Unhook special message hooks for dropdowns.
+void nsWindow::UnregisterSpecialDropdownHooks() {
+  DISPLAY_NMM_PRT(
+      "***************** De-installing Msg Hooks ***************\n");
+
+  if (sCallProcHook) {
+    DISPLAY_NMM_PRT("***** Unhooking sCallProcHook!\n");
+    if (!::UnhookWindowsHookEx(sCallProcHook)) {
+      DISPLAY_NMM_PRT("***** UnhookWindowsHookEx failed for sCallProcHook!\n");
+    }
+    sCallProcHook = nullptr;
+  }
+
+  if (sMsgFilterHook) {
+    DISPLAY_NMM_PRT("***** Unhooking sMsgFilterHook!\n");
+    if (!::UnhookWindowsHookEx(sMsgFilterHook)) {
+      DISPLAY_NMM_PRT("***** UnhookWindowsHookEx failed for sMsgFilterHook!\n");
+    }
+    sMsgFilterHook = nullptr;
+  }
+
+  if (sCallMouseHook) {
+    DISPLAY_NMM_PRT("***** Unhooking sCallMouseHook!\n");
+    if (!::UnhookWindowsHookEx(sCallMouseHook)) {
+      DISPLAY_NMM_PRT("***** UnhookWindowsHookEx failed for sCallMouseHook!\n");
+    }
+    sCallMouseHook = nullptr;
+  }
+}
+
+// This timer is designed to only fire one time at most each time a "hook"
+// function is used to rollup the dropdown. In some cases, the timer may be
+// scheduled from the hook, but that hook event or a subsequent event may roll
+// up the dropdown before this timer function is executed.
+//
+// For example, if an MFC control takes focus, the combobox will lose focus and
+// rollup before this function fires.
+VOID CALLBACK nsWindow::HookTimerForPopups(HWND hwnd, UINT uMsg, UINT idEvent,
+                                           DWORD dwTime) {
+  if (sHookTimerId != 0) {
+    // if the window is nullptr then we need to use the ID to kill the timer
+    DebugOnly<BOOL> status = ::KillTimer(nullptr, sHookTimerId);
+    NS_ASSERTION(status, "Hook Timer was not killed.");
+    sHookTimerId = 0;
+  }
+
+  if (sRollupMsgId != 0) {
+    // Note: DealWithPopups does the check to make sure that the rollup widget
+    // is set.
+    LRESULT popupHandlingResult;
+    nsAutoRollup autoRollup;
+    DealWithPopups(sRollupMsgWnd, sRollupMsgId, 0, 0, &popupHandlingResult);
+    sRollupMsgId = 0;
+    sRollupMsgWnd = nullptr;
+  }
+}
+
+static bool IsDifferentThreadWindow(HWND aWnd) {
+  return ::GetCurrentThreadId() != ::GetWindowThreadProcessId(aWnd, nullptr);
+}
+
+// static
+bool nsWindow::EventIsInsideWindow(nsWindow* aWindow,
+                                   Maybe<POINT> aEventPoint) {
+  RECT r;
+  ::GetWindowRect(aWindow->mWnd, &r);
+  POINT mp;
+  if (aEventPoint) {
+    mp = *aEventPoint;
+  } else {
+    DWORD pos = ::GetMessagePos();
+    mp.x = GET_X_LPARAM(pos);
+    mp.y = GET_Y_LPARAM(pos);
+  }
+
+  auto margin = aWindow->mInputRegion.mMargin;
+  if (margin > 0) {
+    r.top += margin;
+    r.bottom -= margin;
+    r.left += margin;
+    r.right -= margin;
+  }
+
+  // was the event inside this window?
+  return static_cast<bool>(::PtInRect(&r, mp));
+}
+
+// static
+bool nsWindow::GetPopupsToRollup(nsIRollupListener* aRollupListener,
+                                 uint32_t* aPopupsToRollup,
+                                 Maybe<POINT> aEventPoint) {
+  // If we're dealing with menus, we probably have submenus and we don't want
+  // to rollup some of them if the click is in a parent menu of the current
+  // submenu.
+  *aPopupsToRollup = UINT32_MAX;
+  AutoTArray<nsIWidget*, 5> widgetChain;
+  uint32_t sameTypeCount = aRollupListener->GetSubmenuWidgetChain(&widgetChain);
+  for (uint32_t i = 0; i < widgetChain.Length(); ++i) {
+    nsIWidget* widget = widgetChain[i];
+    if (EventIsInsideWindow(static_cast<nsWindow*>(widget), aEventPoint)) {
+      // Don't roll up if the mouse event occurred within a menu of the
+      // same type. If the mouse event occurred in a menu higher than that,
+      // roll up, but pass the number of popups to Rollup so that only those
+      // of the same type close up.
+      if (i < sameTypeCount) {
+        return false;
+      }
+
+      *aPopupsToRollup = sameTypeCount;
+      break;
+    }
+  }
+  return true;
+}
+
+// static
+bool nsWindow::NeedsToHandleNCActivateDelayed(HWND aWnd) {
+  // While popup is open, popup window might be activated by other application.
+  // At this time, we need to take back focus to the previous window but it
+  // causes flickering its nonclient area because WM_NCACTIVATE comes before
+  // WM_ACTIVATE and we cannot know which window will take focus at receiving
+  // WM_NCACTIVATE. Therefore, we need a hack for preventing the flickerling.
+  //
+  // If non-popup window receives WM_NCACTIVATE at deactivating, default
+  // wndproc shouldn't handle it as deactivating. Instead, at receiving
+  // WM_ACTIVIATE after that, WM_NCACTIVATE should be sent again manually.
+  // This returns true if the window needs to handle WM_NCACTIVATE later.
+
+  nsWindow* window = WinUtils::GetNSWindowPtr(aWnd);
+  return window && !window->IsPopup();
+}
+
+static bool IsTouchSupportEnabled(HWND aWnd) {
+  nsWindow* topWindow =
+      WinUtils::GetNSWindowPtr(WinUtils::GetTopLevelHWND(aWnd, true));
+  return topWindow ? topWindow->IsTouchWindow() : false;
+}
+
+static Maybe<POINT> GetSingleTouch(WPARAM wParam, LPARAM lParam) {
+  Maybe<POINT> ret;
+  uint32_t cInputs = LOWORD(wParam);
+  if (cInputs != 1) {
+    return ret;
+  }
+  TOUCHINPUT input;
+  if (GetTouchInputInfo((HTOUCHINPUT)lParam, cInputs, &input,
+                        sizeof(TOUCHINPUT))) {
+    ret.emplace();
+    ret->x = TOUCH_COORD_TO_PIXEL(input.x);
+    ret->y = TOUCH_COORD_TO_PIXEL(input.y);
+  }
+  // Note that we don't call CloseTouchInputHandle here because we need
+  // to read the touch input info again in OnTouch later.
+  return ret;
+}
+
+// static
+bool nsWindow::DealWithPopups(HWND aWnd, UINT aMessage, WPARAM aWParam,
+                              LPARAM aLParam, LRESULT* aResult) {
+  NS_ASSERTION(aResult, "Bad outResult");
+
+  // XXX Why do we use the return value of WM_MOUSEACTIVATE for all messages?
+  *aResult = MA_NOACTIVATE;
+
+  if (!::IsWindowVisible(aWnd)) {
+    return false;
+  }
+
+  if (MOZ_UNLIKELY(aMessage == WM_KILLFOCUS)) {
+    // NOTE: We deal with this here rather than on the switch below because we
+    // want to do this even if there are no menus to rollup (tooltips don't set
+    // the rollup listener etc).
+    if (RefPtr pm = nsXULPopupManager::GetInstance()) {
+      pm->RollupTooltips();
+    }
+  }
+
+  nsIRollupListener* rollupListener = nsBaseWidget::GetActiveRollupListener();
+  NS_ENSURE_TRUE(rollupListener, false);
+
+  nsCOMPtr<nsIWidget> popup = rollupListener->GetRollupWidget();
+  if (!popup) {
+    return false;
+  }
+
+  static bool sSendingNCACTIVATE = false;
+  static bool sPendingNCACTIVATE = false;
+  uint32_t popupsToRollup = UINT32_MAX;
+
+  bool consumeRollupEvent = false;
+  Maybe<POINT> touchPoint;  // In screen coords.
+
+  // If we rollup with animations but get occluded right away, we might not
+  // advance the refresh driver enough for the animation to finish.
+  auto allowAnimations = nsIRollupListener::AllowAnimations::Yes;
+  nsWindow* popupWindow = static_cast<nsWindow*>(popup.get());
+  UINT nativeMessage = WinUtils::GetNativeMessage(aMessage);
+  switch (nativeMessage) {
+    case WM_TOUCH:
+      if (!IsTouchSupportEnabled(aWnd)) {
+        // If APZ is disabled, don't allow touch inputs to dismiss popups. The
+        // compatibility mouse events will do it instead.
+        return false;
+      }
+      touchPoint = GetSingleTouch(aWParam, aLParam);
+      if (!touchPoint) {
+        return false;
+      }
+      [[fallthrough]];
+    case WM_LBUTTONDOWN:
+    case WM_RBUTTONDOWN:
+    case WM_MBUTTONDOWN:
+    case WM_NCLBUTTONDOWN:
+    case WM_NCRBUTTONDOWN:
+    case WM_NCMBUTTONDOWN:
+      if (nativeMessage != WM_TOUCH && IsTouchSupportEnabled(aWnd) &&
+          MOUSE_INPUT_SOURCE() == MouseEvent_Binding::MOZ_SOURCE_TOUCH) {
+        // If any of these mouse events are really compatibility events that
+        // Windows is sending for touch inputs, then don't allow them to dismiss
+        // popups when APZ is enabled (instead we do the dismissing as part of
+        // WM_TOUCH handling which is more correct).
+        // If we don't do this, then when the user lifts their finger after a
+        // long-press, the WM_RBUTTONDOWN compatibility event that Windows sends
+        // us will dismiss the contextmenu popup that we displayed as part of
+        // handling the long-tap-up.
+        return false;
+      }
+      if (!EventIsInsideWindow(popupWindow, touchPoint) &&
+          GetPopupsToRollup(rollupListener, &popupsToRollup, touchPoint)) {
+        break;
+      }
+      return false;
+    case WM_POINTERDOWN: {
+      WinPointerEvents pointerEvents;
+      if (!pointerEvents.ShouldRollupOnPointerEvent(nativeMessage, aWParam)) {
+        return false;
+      }
+      POINT pt;
+      pt.x = GET_X_LPARAM(aLParam);
+      pt.y = GET_Y_LPARAM(aLParam);
+      if (!GetPopupsToRollup(rollupListener, &popupsToRollup, Some(pt))) {
+        return false;
+      }
+      if (EventIsInsideWindow(popupWindow, Some(pt))) {
+        // Don't roll up if the event is inside the popup window.
+        return false;
+      }
+    } break;
+    case MOZ_WM_DMANIP: {
+      POINT pt;
+      ::GetCursorPos(&pt);
+      if (!GetPopupsToRollup(rollupListener, &popupsToRollup, Some(pt))) {
+        return false;
+      }
+      if (EventIsInsideWindow(popupWindow, Some(pt))) {
+        // Don't roll up if the event is inside the popup window
+        return false;
+      }
+    } break;
+    case WM_MOUSEWHEEL:
+    case WM_MOUSEHWHEEL:
+      // We need to check if the popup thinks that it should cause closing
+      // itself when mouse wheel events are fired outside the rollup widget.
+      if (!EventIsInsideWindow(popupWindow)) {
+        // Check if we should consume this event even if we don't roll-up:
+        consumeRollupEvent = rollupListener->ShouldConsumeOnMouseWheelEvent();
+        *aResult = MA_ACTIVATE;
+        if (rollupListener->ShouldRollupOnMouseWheelEvent() &&
+            GetPopupsToRollup(rollupListener, &popupsToRollup)) {
+          break;
+        }
+      }
+      return consumeRollupEvent;
+
+    case WM_ACTIVATEAPP:
+      allowAnimations = nsIRollupListener::AllowAnimations::No;
+      break;
+
+    case WM_ACTIVATE: {
+      WndProcUrgentInvocation::Marker _marker;
+
+      // NOTE: Don't handle WA_INACTIVE for preventing popup taking focus
+      // because we cannot distinguish it's caused by mouse or not.
+      if (LOWORD(aWParam) == WA_ACTIVE && aLParam) {
+        nsWindow* window = WinUtils::GetNSWindowPtr(aWnd);
+        if (window && (window->IsPopup() || window->mIsAlert)) {
+          // Cancel notifying widget listeners of deactivating the previous
+          // active window (see WM_KILLFOCUS case in ProcessMessage()).
+          sJustGotDeactivate = false;
+          // Reactivate the window later.
+          ::PostMessageW(aWnd, MOZ_WM_REACTIVATE, aWParam, aLParam);
+          return true;
+        }
+        // Don't rollup the popup when focus moves back to the parent window
+        // from a popup because such case is caused by strange mouse drivers.
+        nsWindow* prevWindow =
+            WinUtils::GetNSWindowPtr(reinterpret_cast<HWND>(aLParam));
+        if (prevWindow && prevWindow->IsPopup()) {
+          // Consume this message here since previous window must not have
+          // been inactivated since we've already stopped accepting the
+          // inactivation below.
+          return true;
+        }
+      } else if (LOWORD(aWParam) == WA_INACTIVE) {
+        nsWindow* activeWindow =
+            WinUtils::GetNSWindowPtr(reinterpret_cast<HWND>(aLParam));
+        if (sPendingNCACTIVATE && NeedsToHandleNCActivateDelayed(aWnd)) {
+          // If focus moves to non-popup widget or focusable popup, the window
+          // needs to update its nonclient area.
+          if (!activeWindow || !activeWindow->IsPopup()) {
+            sSendingNCACTIVATE = true;
+            ::SendMessageW(aWnd, WM_NCACTIVATE, false, 0);
+            sSendingNCACTIVATE = false;
+          }
+          sPendingNCACTIVATE = false;
+        }
+        // If focus moves from/to popup, we don't need to rollup the popup
+        // because such case is caused by strange mouse drivers.  And in
+        // such case, we should consume the message here since we need to
+        // hide this odd focus move from our content.  (If we didn't consume
+        // the message here, ProcessMessage() will notify widget listener of
+        // inactivation and that causes unnecessary reflow for supporting
+        // -moz-window-inactive pseudo class.
+        if (activeWindow) {
+          if (activeWindow->IsPopup()) {
+            return true;
+          }
+          nsWindow* deactiveWindow = WinUtils::GetNSWindowPtr(aWnd);
+          if (deactiveWindow && deactiveWindow->IsPopup()) {
+            return true;
+          }
+        }
+      } else if (LOWORD(aWParam) == WA_CLICKACTIVE) {
+        // If the WM_ACTIVATE message is caused by a click in a popup,
+        // we should not rollup any popups.
+        nsWindow* window = WinUtils::GetNSWindowPtr(aWnd);
+        if ((window && window->IsPopup()) ||
+            !GetPopupsToRollup(rollupListener, &popupsToRollup)) {
+          return false;
+        }
+      }
+      allowAnimations = nsIRollupListener::AllowAnimations::No;
+    } break;
+
+    case MOZ_WM_REACTIVATE:
+      // The previous active window should take back focus.
+      if (::IsWindow(reinterpret_cast<HWND>(aLParam))) {
+        // FYI: Even without this API call, you see expected result (e.g., the
+        //      owner window of the popup keeps active without flickering
+        //      the non-client area).  And also this causes initializing
+        //      TSF and it causes using CPU time a lot.  However, even if we
+        //      consume WM_ACTIVE messages, native focus change has already
+        //      been occurred.  I.e., a popup window is active now.  Therefore,
+        //      you'll see some odd behavior if we don't reactivate the owner
+        //      window here.  For example, if you do:
+        //        1. Turn wheel on a bookmark panel.
+        //        2. Turn wheel on another window.
+        //      then, you'll see that the another window becomes active but the
+        //      owner window of the bookmark panel looks still active and the
+        //      bookmark panel keeps open.  The reason is that the first wheel
+        //      operation gives focus to the bookmark panel.  Therefore, when
+        //      the next operation gives focus to the another window, previous
+        //      focus window is the bookmark panel (i.e., a popup window).
+        //      So, in this case, our hack around here prevents to inactivate
+        //      the owner window and roll up the bookmark panel.
+        ::SetForegroundWindow(reinterpret_cast<HWND>(aLParam));
+      }
+      return true;
+
+    case WM_NCACTIVATE:
+      if (!aWParam && !sSendingNCACTIVATE &&
+          NeedsToHandleNCActivateDelayed(aWnd)) {
+        // Don't just consume WM_NCACTIVATE. It doesn't handle only the
+        // nonclient area state change.
+        ::DefWindowProcW(aWnd, aMessage, TRUE, aLParam);
+        // Accept the deactivating because it's necessary to receive following
+        // WM_ACTIVATE.
+        *aResult = TRUE;
+        sPendingNCACTIVATE = true;
+        return true;
+      }
+      return false;
+
+    case WM_MOUSEACTIVATE:
+      if (!EventIsInsideWindow(popupWindow) &&
+          GetPopupsToRollup(rollupListener, &popupsToRollup)) {
+        // WM_MOUSEACTIVATE may be caused by moving the mouse (e.g., X-mouse
+        // of TweakUI is enabled. Then, check if the popup should be rolled up
+        // with rollup listener. If not, just consume the message.
+        if (HIWORD(aLParam) == WM_MOUSEMOVE &&
+            !rollupListener->ShouldRollupOnMouseActivate()) {
+          return true;
+        }
+        // Otherwise, it should be handled by wndproc.
+        return false;
+      }
+
+      // Prevent the click inside the popup from causing a change in window
+      // activation. Since the popup is shown non-activated, we need to eat any
+      // requests to activate the window while it is displayed. Windows will
+      // automatically activate the popup on the mousedown otherwise.
+      return true;
+
+    case WM_SHOWWINDOW:
+      // If the window is being minimized, close popups.
+      if (aLParam == SW_PARENTCLOSING) {
+        allowAnimations = nsIRollupListener::AllowAnimations::No;
+        break;
+      }
+      return false;
+
+    case WM_KILLFOCUS:
+      // If focus moves to other window created in different process/thread,
+      // e.g., a plugin window, popups should be rolled up.
+      if (IsDifferentThreadWindow(reinterpret_cast<HWND>(aWParam))) {
+        allowAnimations = nsIRollupListener::AllowAnimations::No;
+        break;
+      }
+      return false;
+
+    case WM_MOVING:
+    case WM_MENUSELECT:
+      break;
+
+    default:
+      return false;
+  }
+
+  // Only need to deal with the last rollup for left mouse down events.
+  NS_ASSERTION(!nsAutoRollup::GetLastRollup(), "last rollup is null");
+
+  nsIRollupListener::RollupOptions rollupOptions{
+      popupsToRollup,
+      nsIRollupListener::FlushViews::Yes,
+      /* mPoint = */ nullptr,
+      allowAnimations,
+  };
+
+  if (nativeMessage == WM_TOUCH || nativeMessage == WM_LBUTTONDOWN ||
+      nativeMessage == WM_POINTERDOWN) {
+    LayoutDeviceIntPoint pos;
+    if (nativeMessage == WM_TOUCH) {
+      pos.x = touchPoint->x;
+      pos.y = touchPoint->y;
+    } else {
+      POINT pt;
+      pt.x = GET_X_LPARAM(aLParam);
+      pt.y = GET_Y_LPARAM(aLParam);
+      // POINTERDOWN is already in screen coords.
+      if (nativeMessage == WM_LBUTTONDOWN) {
+        ::ClientToScreen(aWnd, &pt);
+      }
+      pos = LayoutDeviceIntPoint(pt.x, pt.y);
+    }
+
+    rollupOptions.mPoint = &pos;
+    nsIContent* lastRollup = nullptr;
+    consumeRollupEvent = rollupListener->Rollup(rollupOptions, &lastRollup);
+    nsAutoRollup::SetLastRollup(lastRollup);
+  } else {
+    consumeRollupEvent = rollupListener->Rollup(rollupOptions);
+  }
+
+  // Tell hook to stop processing messages
+  sProcessHook = false;
+  sRollupMsgId = 0;
+  sRollupMsgWnd = nullptr;
+
+  // If we are NOT supposed to be consuming events, let it go through
+  if (consumeRollupEvent && nativeMessage != WM_RBUTTONDOWN) {
+    *aResult = MA_ACTIVATE;
+    return true;
+  }
+
+  return false;
+}
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: Misc. utility methods and functions.
+ **
+ ** General use.
+ **
+ **************************************************************
+ **************************************************************/
+
+// Note that the result of GetTopLevelWindow method can be different from the
+// result of WinUtils::GetTopLevelHWND().  The result can be non-floating
+// window.  Because our top level window may be contained in another window
+// which is not managed by us.
+nsWindow* nsWindow::GetTopLevelWindow(bool aStopOnDialogOrPopup) {
+  nsWindow* curWindow = this;
+
+  while (true) {
+    if (aStopOnDialogOrPopup) {
+      switch (curWindow->mWindowType) {
+        case WindowType::Dialog:
+        case WindowType::Popup:
+          return curWindow;
+        default:
+          break;
+      }
+    }
+
+    // Retrieve the top level parent or owner window
+    nsWindow* parentWindow = curWindow->GetParentWindow(true);
+
+    if (!parentWindow) return curWindow;
+
+    curWindow = parentWindow;
+  }
+}
+
+// Set a flag if hwnd is a (non-popup) visible window from this process,
+// and bail out of the enumeration. Otherwise leave the flag unmodified
+// and continue the enumeration.
+// lParam must be a bool* pointing at the flag to be set.
+static BOOL CALLBACK EnumVisibleWindowsProc(HWND hwnd, LPARAM lParam) {
+  DWORD pid;
+  ::GetWindowThreadProcessId(hwnd, &pid);
+  if (pid == ::GetCurrentProcessId() && ::IsWindowVisible(hwnd)) {
+    // Don't count popups as visible windows, since they don't take focus,
+    // in case we only have a popup visible (see bug 1554490 where the gfx
+    // test window is an offscreen popup).
+    nsWindow* window = WinUtils::GetNSWindowPtr(hwnd);
+    if (!window || !window->IsPopup()) {
+      bool* windowsVisible = reinterpret_cast<bool*>(lParam);
+      *windowsVisible = true;
+      return FALSE;
+    }
+  }
+  return TRUE;
+}
+
+// Determine if it would be ok to activate a window, taking focus.
+// We want to avoid stealing focus from another app (bug 225305).
+bool nsWindow::CanTakeFocus() {
+  HWND fgWnd = ::GetForegroundWindow();
+  if (!fgWnd) {
+    // There is no foreground window, so don't worry about stealing focus.
+    return true;
+  }
+  // We can take focus if the current foreground window is already from
+  // this process.
+  DWORD pid;
+  ::GetWindowThreadProcessId(fgWnd, &pid);
+  if (pid == ::GetCurrentProcessId()) {
+    return true;
+  }
+
+  bool windowsVisible = false;
+  ::EnumWindows(EnumVisibleWindowsProc,
+                reinterpret_cast<LPARAM>(&windowsVisible));
+
+  if (!windowsVisible) {
+    // We're probably creating our first visible window, allow that to
+    // take focus.
+    return true;
+  }
+  return false;
+}
+
+/* static */ const wchar_t* nsWindow::GetMainWindowClass() {
+  static const wchar_t* sMainWindowClass = nullptr;
+  if (!sMainWindowClass) {
+    nsAutoString className;
+    Preferences::GetString("ui.window_class_override", className);
+    if (!className.IsEmpty()) {
+      sMainWindowClass = wcsdup(className.get());
+    } else {
+      sMainWindowClass = kClassNameGeneral;
+    }
+  }
+  return sMainWindowClass;
+}
+
+LPARAM nsWindow::lParamToScreen(LPARAM lParam) {
+  POINT pt;
+  pt.x = GET_X_LPARAM(lParam);
+  pt.y = GET_Y_LPARAM(lParam);
+  ::ClientToScreen(mWnd, &pt);
+  return MAKELPARAM(pt.x, pt.y);
+}
+
+LPARAM nsWindow::lParamToClient(LPARAM lParam) {
+  POINT pt;
+  pt.x = GET_X_LPARAM(lParam);
+  pt.y = GET_Y_LPARAM(lParam);
+  ::ScreenToClient(mWnd, &pt);
+  return MAKELPARAM(pt.x, pt.y);
+}
+
+WPARAM nsWindow::wParamFromGlobalMouseState() {
+  WPARAM result = 0;
+
+  if (!!::GetKeyState(VK_CONTROL)) {
+    result |= MK_CONTROL;
+  }
+
+  if (!!::GetKeyState(VK_SHIFT)) {
+    result |= MK_SHIFT;
+  }
+
+  if (!!::GetKeyState(VK_LBUTTON)) {
+    result |= MK_LBUTTON;
+  }
+
+  if (!!::GetKeyState(VK_MBUTTON)) {
+    result |= MK_MBUTTON;
+  }
+
+  if (!!::GetKeyState(VK_RBUTTON)) {
+    result |= MK_RBUTTON;
+  }
+
+  if (!!::GetKeyState(VK_XBUTTON1)) {
+    result |= MK_XBUTTON1;
+  }
+
+  if (!!::GetKeyState(VK_XBUTTON2)) {
+    result |= MK_XBUTTON2;
+  }
+
+  return result;
+}
+
+void nsWindow::PickerOpen() {
+  AssertIsOnMainThread();
+  mPickerDisplayCount++;
+}
+
+void nsWindow::PickerClosed() {
+  AssertIsOnMainThread();
+  NS_ASSERTION(mPickerDisplayCount > 0, "mPickerDisplayCount out of sync!");
+  if (!mPickerDisplayCount) return;
+  mPickerDisplayCount--;
+
+  // WORKAROUND FOR UNDOCUMENTED BEHAVIOR: `IFileDialog::Show` disables the
+  // top-level ancestor of its provided owner-window. If the modal window's
+  // container process crashes, it will never get a chance to undo that, so we
+  // do it manually here.
+  //
+  // Note that this may cause problems in the embedded case if you reparent a
+  // subtree of the native window hierarchy containing a Gecko window while that
+  // Gecko window has a file-dialog open.
+  if (!mPickerDisplayCount) {
+    ::EnableWindow(::GetAncestor(GetWindowHandle(), GA_ROOT), TRUE);
+  }
+
+  if (!mPickerDisplayCount && mDestroyCalled) {
+    Destroy();
+  }
+}
+
+bool nsWindow::WidgetTypeSupportsAcceleration() {
+  // We don't currently support using an accelerated layer manager with
+  // transparent windows so don't even try. I'm also not sure if we even
+  // want to support this case. See bug 593471.
+  //
+  // Windows' support for transparent accelerated surfaces isn't great.
+  // Some possible approaches:
+  //  - Readback the data and update it using
+  //  UpdateLayeredWindow/UpdateLayeredWindowIndirect
+  //    This is what WPF does. See
+  //    CD3DDeviceLevel1::PresentWithGDI/CD3DSwapChainWithSwDC in WpfGfx. The
+  //    rationale for not using IDirect3DSurface9::GetDC is explained here:
+  //    https://web.archive.org/web/20160521191104/https://blogs.msdn.microsoft.com/dwayneneed/2008/09/08/transparent-windows-in-wpf/
+  //  - Use D3D11_RESOURCE_MISC_GDI_COMPATIBLE, IDXGISurface1::GetDC(),
+  //    and UpdateLayeredWindowIndirect.
+  //    This is suggested here:
+  //    https://docs.microsoft.com/en-us/archive/msdn-magazine/2009/december/windows-with-c-layered-windows-with-direct2d
+  //    but might have the same problem that IDirect3DSurface9::GetDC has.
+  //  - Creating the window with the WS_EX_NOREDIRECTIONBITMAP flag and use
+  //  DirectComposition.
+  //    Not supported on Win7.
+  //  - Using DwmExtendFrameIntoClientArea with negative margins and something
+  //  to turn off the glass effect.
+  //    This doesn't work when the DWM is not running (Win7)
+  //
+  // Also see bug 1150376, D3D11 composition can cause issues on some devices
+  // on Windows 7 where presentation fails randomly for windows with drop
+  // shadows.
+  return mTransparencyMode != TransparencyMode::Transparent &&
+         !(IsPopup() && DeviceManagerDx::Get()->IsWARP());
+}
+
+bool nsWindow::DispatchTouchEventFromWMPointer(
+    UINT msg, LPARAM aLParam, const WinPointerInfo& aPointerInfo,
+    mozilla::MouseButton aButton) {
+  MultiTouchInput::MultiTouchType touchType;
+  switch (msg) {
+    case WM_POINTERDOWN:
+      touchType = MultiTouchInput::MULTITOUCH_START;
+      break;
+    case WM_POINTERUPDATE:
+      if (aPointerInfo.mPressure == 0) {
+        return false;  // hover
+      }
+      touchType = MultiTouchInput::MULTITOUCH_MOVE;
+      break;
+    case WM_POINTERUP:
+      touchType = MultiTouchInput::MULTITOUCH_END;
+      break;
+    default:
+      return false;
+  }
+
+  nsPointWin touchPoint;
+  touchPoint.x = GET_X_LPARAM(aLParam);
+  touchPoint.y = GET_Y_LPARAM(aLParam);
+  touchPoint.ScreenToClient(mWnd);
+
+  SingleTouchData touchData(static_cast<int32_t>(aPointerInfo.pointerId),
+                            ScreenIntPoint::FromUnknownPoint(touchPoint),
+                            ScreenSize(1, 1),  // pixel size radius for pen
+                            0.0f,              // no radius rotation
+                            aPointerInfo.mPressure);
+  touchData.mTiltX = aPointerInfo.tiltX;
+  touchData.mTiltY = aPointerInfo.tiltY;
+  touchData.mTwist = aPointerInfo.twist;
+
+  MultiTouchInput touchInput;
+  touchInput.mType = touchType;
+  touchInput.mTimeStamp = GetMessageTimeStamp(::GetMessageTime());
+  touchInput.mTouches.AppendElement(touchData);
+  touchInput.mButton = aButton;
+  touchInput.mButtons = aPointerInfo.mButtons;
+
+  // POINTER_INFO.dwKeyStates can't be used as it only supports Shift and Ctrl
+  ModifierKeyState modifierKeyState;
+  touchInput.modifiers = modifierKeyState.GetModifiers();
+
+  DispatchTouchInput(touchInput, MouseEvent_Binding::MOZ_SOURCE_PEN);
+  return true;
+}
+
+static MouseButton PenFlagsToMouseButton(PEN_FLAGS aPenFlags) {
+  // Theoretically flags can be set together but they do not
+  if (aPenFlags & PEN_FLAG_BARREL) {
+    return MouseButton::eSecondary;
+  }
+  if (aPenFlags & PEN_FLAG_ERASER) {
+    return MouseButton::eEraser;
+  }
+  return MouseButton::ePrimary;
+}
+
+bool nsWindow::OnPointerEvents(UINT msg, WPARAM aWParam, LPARAM aLParam) {
+  if (!mAPZC) {
+    // APZ is not available on context menu. Follow the behavior of touch input
+    // which fallbacks to WM_LBUTTON* and WM_GESTURE, to keep consistency.
+    return false;
+  }
+  if (!mPointerEvents.ShouldHandleWinPointerMessages(msg, aWParam)) {
+    return false;
+  }
+  if (!mPointerEvents.ShouldFirePointerEventByWinPointerMessages()) {
+    // We have to handle WM_POINTER* to fetch and cache pen related information
+    // and fire WidgetMouseEvent with the cached information the WM_*BUTTONDOWN
+    // handler. This is because Windows doesn't support ::DoDragDrop in the
+    // touch or pen message handlers.
+    mPointerEvents.ConvertAndCachePointerInfo(msg, aWParam);
+    // Don't consume the Windows WM_POINTER* messages
+    return false;
+  }
+
+  uint32_t pointerId = mPointerEvents.GetPointerId(aWParam);
+  POINTER_PEN_INFO penInfo{};
+  if (!mPointerEvents.GetPointerPenInfo(pointerId, &penInfo)) {
+    return false;
+  }
+
+  // When dispatching mouse events with pen, there may be some
+  // WM_POINTERUPDATE messages between WM_POINTERDOWN and WM_POINTERUP with
+  // small movements. Those events will reset sLastMousePoint and reset
+  // sLastClickCount. To prevent that, we keep the last pen down position
+  // and compare it with the subsequent WM_POINTERUPDATE. If the movement is
+  // smaller than GetSystemMetrics(SM_CXDRAG), then we suppress firing
+  // eMouseMove for WM_POINTERUPDATE.
+  static POINT sLastPointerDownPoint = {0};
+
+  // We don't support chorded buttons for pen. Keep the button at
+  // WM_POINTERDOWN.
+  static mozilla::MouseButton sLastPenDownButton = MouseButton::ePrimary;
+  static bool sPointerDown = false;
+
+  EventMessage message;
+  mozilla::MouseButton button = MouseButton::ePrimary;
+  switch (msg) {
+    case WM_POINTERDOWN: {
+      LayoutDeviceIntPoint eventPoint(GET_X_LPARAM(aLParam),
+                                      GET_Y_LPARAM(aLParam));
+      sLastPointerDownPoint.x = eventPoint.x;
+      sLastPointerDownPoint.y = eventPoint.y;
+      message = eMouseDown;
+      button = PenFlagsToMouseButton(penInfo.penFlags);
+      sLastPenDownButton = button;
+      sPointerDown = true;
+    } break;
+    case WM_POINTERUP:
+      message = eMouseUp;
+      MOZ_ASSERT(sPointerDown, "receive WM_POINTERUP w/o WM_POINTERDOWN");
+      button = sPointerDown ? sLastPenDownButton : MouseButton::ePrimary;
+      sPointerDown = false;
+      break;
+    case WM_POINTERUPDATE:
+      message = eMouseMove;
+      if (sPointerDown) {
+        LayoutDeviceIntPoint eventPoint(GET_X_LPARAM(aLParam),
+                                        GET_Y_LPARAM(aLParam));
+        int32_t movementX = sLastPointerDownPoint.x > eventPoint.x
+                                ? sLastPointerDownPoint.x - eventPoint.x.value
+                                : eventPoint.x.value - sLastPointerDownPoint.x;
+        int32_t movementY = sLastPointerDownPoint.y > eventPoint.y
+                                ? sLastPointerDownPoint.y - eventPoint.y.value
+                                : eventPoint.y.value - sLastPointerDownPoint.y;
+        bool insideMovementThreshold =
+            movementX < (int32_t)::GetSystemMetrics(SM_CXDRAG) &&
+            movementY < (int32_t)::GetSystemMetrics(SM_CYDRAG);
+
+        if (insideMovementThreshold) {
+          // Suppress firing eMouseMove for WM_POINTERUPDATE if the movement
+          // from last WM_POINTERDOWN is smaller than SM_CXDRAG / SM_CYDRAG
+          return false;
+        }
+        button = sLastPenDownButton;
+      }
+      break;
+    case WM_POINTERLEAVE:
+      message = eMouseExitFromWidget;
+      break;
+    default:
+      return false;
+  }
+
+  // Windows defines the pen pressure is normalized to a range between 0 and
+  // 1024. Convert it to float.
+  float pressure = penInfo.pressure ? (float)penInfo.pressure / 1024 : 0;
+  int16_t buttons = sPointerDown
+                        ? nsContentUtils::GetButtonsFlagForButton(button)
+                        : MouseButtonsFlag::eNoButtons;
+  WinPointerInfo pointerInfo(pointerId, penInfo.tiltX, penInfo.tiltY, pressure,
+                             buttons);
+  // Per
+  // https://learn.microsoft.com/en-us/windows/win32/api/winuser/ns-winuser-pointer_pen_info,
+  // the rotation is normalized in a range of 0 to 359.
+  MOZ_ASSERT(penInfo.rotation <= 359);
+  pointerInfo.twist = (int32_t)penInfo.rotation;
+
+  // Fire touch events but not when the barrel button is pressed.
+  if (button != MouseButton::eSecondary &&
+      StaticPrefs::dom_w3c_pointer_events_scroll_by_pen_enabled() &&
+      DispatchTouchEventFromWMPointer(msg, aLParam, pointerInfo, button)) {
+    return true;
+  }
+
+  // The aLParam of WM_POINTER* is the screen location. Convert it to client
+  // location
+  LPARAM newLParam = lParamToClient(aLParam);
+  DispatchMouseEvent(message, aWParam, newLParam, false, button,
+                     MouseEvent_Binding::MOZ_SOURCE_PEN, &pointerInfo);
+
+  if (button == MouseButton::eSecondary && message == eMouseUp) {
+    // Fire eContextMenu manually since consuming WM_POINTER* blocks
+    // WM_CONTEXTMENU
+    DispatchMouseEvent(eContextMenu, aWParam, newLParam, false, button,
+                       MouseEvent_Binding::MOZ_SOURCE_PEN, &pointerInfo);
+  }
+  // Consume WM_POINTER* to stop Windows fires WM_*BUTTONDOWN / WM_*BUTTONUP
+  // WM_MOUSEMOVE.
+  return true;
+}
+
+void nsWindow::GetCompositorWidgetInitData(
+    mozilla::widget::CompositorWidgetInitData* aInitData) {
+  *aInitData = WinCompositorWidgetInitData(
+      reinterpret_cast<uintptr_t>(mWnd),
+      reinterpret_cast<uintptr_t>(static_cast<nsIWidget*>(this)),
+      mTransparencyMode, mFrameState->GetSizeMode());
+}
+
+bool nsWindow::SynchronouslyRepaintOnResize() { return false; }
+
+void nsWindow::MaybeDispatchInitialFocusEvent() {
+  if (mIsShowingPreXULSkeletonUI && ::GetActiveWindow() == mWnd) {
+    DispatchFocusToTopLevelWindow(true);
+  }
+}
+
+already_AddRefed<nsIWidget> nsIWidget::CreateTopLevelWindow() {
+  nsCOMPtr<nsIWidget> window = new nsWindow();
+  return window.forget();
+}
+
+already_AddRefed<nsIWidget> nsIWidget::CreateChildWindow() {
+  nsCOMPtr<nsIWidget> window = new nsWindow(true);
+  return window.forget();
+}
+
+// static
+bool nsWindow::InitTouchInjection() {
+  if (!sTouchInjectInitialized) {
+    // Initialize touch injection on the first call
+    HMODULE hMod = LoadLibraryW(kUser32LibName);
+    if (!hMod) {
+      return false;
+    }
+
+    InitializeTouchInjectionPtr func =
+        (InitializeTouchInjectionPtr)GetProcAddress(hMod,
+                                                    "InitializeTouchInjection");
+    if (!func) {
+      WinUtils::Log("InitializeTouchInjection not available.");
+      return false;
+    }
+
+    if (!func(TOUCH_INJECT_MAX_POINTS, TOUCH_FEEDBACK_DEFAULT)) {
+      WinUtils::Log("InitializeTouchInjection failure. GetLastError=%d",
+                    GetLastError());
+      return false;
+    }
+
+    sInjectTouchFuncPtr =
+        (InjectTouchInputPtr)GetProcAddress(hMod, "InjectTouchInput");
+    if (!sInjectTouchFuncPtr) {
+      WinUtils::Log("InjectTouchInput not available.");
+      return false;
+    }
+    sTouchInjectInitialized = true;
+  }
+  return true;
+}
+
+bool nsWindow::InjectTouchPoint(uint32_t aId, LayoutDeviceIntPoint& aPoint,
+                                POINTER_FLAGS aFlags, uint32_t aPressure,
+                                uint32_t aOrientation) {
+  if (aId > TOUCH_INJECT_MAX_POINTS) {
+    WinUtils::Log("Pointer ID exceeds maximum. See TOUCH_INJECT_MAX_POINTS.");
+    return false;
+  }
+
+  POINTER_TOUCH_INFO info{};
+
+  info.touchFlags = TOUCH_FLAG_NONE;
+  info.touchMask =
+      TOUCH_MASK_CONTACTAREA | TOUCH_MASK_ORIENTATION | TOUCH_MASK_PRESSURE;
+  info.pressure = aPressure;
+  info.orientation = aOrientation;
+
+  info.pointerInfo.pointerFlags = aFlags;
+  info.pointerInfo.pointerType = PT_TOUCH;
+  info.pointerInfo.pointerId = aId;
+  info.pointerInfo.ptPixelLocation.x = aPoint.x;
+  info.pointerInfo.ptPixelLocation.y = aPoint.y;
+
+  info.rcContact.top = info.pointerInfo.ptPixelLocation.y - 2;
+  info.rcContact.bottom = info.pointerInfo.ptPixelLocation.y + 2;
+  info.rcContact.left = info.pointerInfo.ptPixelLocation.x - 2;
+  info.rcContact.right = info.pointerInfo.ptPixelLocation.x + 2;
+
+  for (int i = 0; i < 3; i++) {
+    if (sInjectTouchFuncPtr(1, &info)) {
+      break;
+    }
+    DWORD error = GetLastError();
+    if (error == ERROR_NOT_READY && i < 2) {
+      // We sent it too quickly after the previous injection (see bug 1535140
+      // comment 10). On the first loop iteration we just yield (via Sleep(0))
+      // and try again. If it happens again on the second loop iteration we
+      // explicitly Sleep(1) and try again. If that doesn't work either we just
+      // error out.
+      ::Sleep(i);
+      continue;
+    }
+    WinUtils::Log("InjectTouchInput failure. GetLastError=%d", error);
+    return false;
+  }
+  return true;
+}
+
+void nsWindow::ChangedDPI() {
+  if (mWidgetListener) {
+    if (PresShell* presShell = mWidgetListener->GetPresShell()) {
+      presShell->BackingScaleFactorChanged();
+    }
+  }
+}
+
+static Result<POINTER_FLAGS, nsresult> PointerStateToFlag(
+    nsWindow::TouchPointerState aPointerState, bool isUpdate) {
+  bool hover = aPointerState & nsWindow::TOUCH_HOVER;
+  bool contact = aPointerState & nsWindow::TOUCH_CONTACT;
+  bool remove = aPointerState & nsWindow::TOUCH_REMOVE;
+  bool cancel = aPointerState & nsWindow::TOUCH_CANCEL;
+
+  POINTER_FLAGS flags;
+  if (isUpdate) {
+    // We know about this pointer, send an update
+    flags = POINTER_FLAG_UPDATE;
+    if (hover) {
+      flags |= POINTER_FLAG_INRANGE;
+    } else if (contact) {
+      flags |= POINTER_FLAG_INCONTACT | POINTER_FLAG_INRANGE;
+    } else if (remove) {
+      flags = POINTER_FLAG_UP;
+    }
+
+    if (cancel) {
+      flags |= POINTER_FLAG_CANCELED;
+    }
+  } else {
+    // Missing init state, error out
+    if (remove || cancel) {
+      return Err(NS_ERROR_INVALID_ARG);
+    }
+
+    // Create a new pointer
+    flags = POINTER_FLAG_INRANGE;
+    if (contact) {
+      flags |= POINTER_FLAG_INCONTACT | POINTER_FLAG_DOWN;
+    }
+  }
+  return flags;
+}
+
+nsresult nsWindow::SynthesizeNativeTouchPoint(
+    uint32_t aPointerId, nsIWidget::TouchPointerState aPointerState,
+    LayoutDeviceIntPoint aPoint, double aPointerPressure,
+    uint32_t aPointerOrientation, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "touchpoint");
+
+  if (StaticPrefs::apz_test_fails_with_native_injection() ||
+      !InitTouchInjection()) {
+    // If we don't have touch injection from the OS, or if we are running a test
+    // that cannot properly inject events to satisfy the OS requirements (see
+    // bug 1313170)  we can just fake it and synthesize the events from here.
+    MOZ_ASSERT(NS_IsMainThread());
+    if (aPointerState == TOUCH_HOVER) {
+      return NS_ERROR_UNEXPECTED;
+    }
+
+    if (!mSynthesizedTouchInput) {
+      mSynthesizedTouchInput = MakeUnique<MultiTouchInput>();
+    }
+
+    WidgetEventTime time = CurrentMessageWidgetEventTime();
+    LayoutDeviceIntPoint pointInWindow = aPoint - WidgetToScreenOffset();
+    MultiTouchInput inputToDispatch = UpdateSynthesizedTouchState(
+        mSynthesizedTouchInput.get(), time.mTimeStamp, aPointerId,
+        aPointerState, pointInWindow, aPointerPressure, aPointerOrientation);
+    DispatchTouchInput(inputToDispatch);
+    return NS_OK;
+  }
+
+  // win api expects a value from 0 to 1024. aPointerPressure is a value
+  // from 0.0 to 1.0.
+  uint32_t pressure = (uint32_t)ceil(aPointerPressure * 1024);
+
+  // If we already know about this pointer id get it's record
+  return mActivePointers.WithEntryHandle(aPointerId, [&](auto&& entry) {
+    POINTER_FLAGS flags;
+    // Can't use MOZ_TRY_VAR because it confuses WithEntryHandle
+    auto result = PointerStateToFlag(aPointerState, !!entry);
+    if (result.isOk()) {
+      flags = result.unwrap();
+    } else {
+      return result.unwrapErr();
+    }
+
+    if (!entry) {
+      entry.Insert(MakeUnique<PointerInfo>(aPointerId, aPoint,
+                                           PointerInfo::PointerType::TOUCH));
+    } else {
+      if (entry.Data()->mType != PointerInfo::PointerType::TOUCH) {
+        return NS_ERROR_UNEXPECTED;
+      }
+      if (aPointerState & TOUCH_REMOVE) {
+        // Remove the pointer from our tracking list. This is UniquePtr wrapped,
+        // so shouldn't leak.
+        entry.Remove();
+      }
+    }
+
+    return !InjectTouchPoint(aPointerId, aPoint, flags, pressure,
+                             aPointerOrientation)
+               ? NS_ERROR_UNEXPECTED
+               : NS_OK;
+  });
+}
+
+nsresult nsWindow::ClearNativeTouchSequence(nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "cleartouch");
+  if (!sTouchInjectInitialized) {
+    return NS_OK;
+  }
+
+  // cancel all input points
+  for (auto iter = mActivePointers.Iter(); !iter.Done(); iter.Next()) {
+    auto* info = iter.UserData();
+    if (info->mType != PointerInfo::PointerType::TOUCH) {
+      continue;
+    }
+    InjectTouchPoint(info->mPointerId, info->mPosition, POINTER_FLAG_CANCELED);
+    iter.Remove();
+  }
+
+  nsBaseWidget::ClearNativeTouchSequence(nullptr);
+
+  return NS_OK;
+}
+
+#if !defined(NTDDI_WIN10_RS5) || (NTDDI_VERSION < NTDDI_WIN10_RS5)
+static CreateSyntheticPointerDevicePtr CreateSyntheticPointerDevice;
+static DestroySyntheticPointerDevicePtr DestroySyntheticPointerDevice;
+static InjectSyntheticPointerInputPtr InjectSyntheticPointerInput;
+#endif
+static HSYNTHETICPOINTERDEVICE sSyntheticPenDevice;
+
+static bool InitPenInjection() {
+  if (sSyntheticPenDevice) {
+    return true;
+  }
+#if !defined(NTDDI_WIN10_RS5) || (NTDDI_VERSION < NTDDI_WIN10_RS5)
+  HMODULE hMod = LoadLibraryW(kUser32LibName);
+  if (!hMod) {
+    return false;
+  }
+  CreateSyntheticPointerDevice =
+      (CreateSyntheticPointerDevicePtr)GetProcAddress(
+          hMod, "CreateSyntheticPointerDevice");
+  if (!CreateSyntheticPointerDevice) {
+    WinUtils::Log("CreateSyntheticPointerDevice not available.");
+    return false;
+  }
+  DestroySyntheticPointerDevice =
+      (DestroySyntheticPointerDevicePtr)GetProcAddress(
+          hMod, "DestroySyntheticPointerDevice");
+  if (!DestroySyntheticPointerDevice) {
+    WinUtils::Log("DestroySyntheticPointerDevice not available.");
+    return false;
+  }
+  InjectSyntheticPointerInput = (InjectSyntheticPointerInputPtr)GetProcAddress(
+      hMod, "InjectSyntheticPointerInput");
+  if (!InjectSyntheticPointerInput) {
+    WinUtils::Log("InjectSyntheticPointerInput not available.");
+    return false;
+  }
+#endif
+  sSyntheticPenDevice =
+      CreateSyntheticPointerDevice(PT_PEN, 1, POINTER_FEEDBACK_DEFAULT);
+  return !!sSyntheticPenDevice;
+}
+
+nsresult nsWindow::SynthesizeNativePenInput(
+    uint32_t aPointerId, nsIWidget::TouchPointerState aPointerState,
+    LayoutDeviceIntPoint aPoint, double aPressure, uint32_t aRotation,
+    int32_t aTiltX, int32_t aTiltY, int32_t aButton, nsIObserver* aObserver) {
+  AutoObserverNotifier notifier(aObserver, "peninput");
+  if (!InitPenInjection()) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  // win api expects a value from 0 to 1024. aPointerPressure is a value
+  // from 0.0 to 1.0.
+  uint32_t pressure = (uint32_t)ceil(aPressure * 1024);
+
+  // If we already know about this pointer id get it's record
+  return mActivePointers.WithEntryHandle(aPointerId, [&](auto&& entry) {
+    POINTER_FLAGS flags;
+    // Can't use MOZ_TRY_VAR because it confuses WithEntryHandle
+    auto result = PointerStateToFlag(aPointerState, !!entry);
+    if (result.isOk()) {
+      flags = result.unwrap();
+    } else {
+      return result.unwrapErr();
+    }
+
+    if (!entry) {
+      entry.Insert(MakeUnique<PointerInfo>(aPointerId, aPoint,
+                                           PointerInfo::PointerType::PEN));
+    } else {
+      if (entry.Data()->mType != PointerInfo::PointerType::PEN) {
+        return NS_ERROR_UNEXPECTED;
+      }
+      if (aPointerState & TOUCH_REMOVE) {
+        // Remove the pointer from our tracking list. This is UniquePtr wrapped,
+        // so shouldn't leak.
+        entry.Remove();
+      }
+    }
+
+    POINTER_TYPE_INFO info{};
+
+    info.type = PT_PEN;
+    info.penInfo.pointerInfo.pointerType = PT_PEN;
+    info.penInfo.pointerInfo.pointerFlags = flags;
+    info.penInfo.pointerInfo.pointerId = aPointerId;
+    info.penInfo.pointerInfo.ptPixelLocation.x = aPoint.x;
+    info.penInfo.pointerInfo.ptPixelLocation.y = aPoint.y;
+
+    info.penInfo.penFlags = PEN_FLAG_NONE;
+    // PEN_FLAG_ERASER is not supported this way, unfortunately.
+    if (aButton == 2) {
+      info.penInfo.penFlags |= PEN_FLAG_BARREL;
+    }
+    info.penInfo.penMask = PEN_MASK_PRESSURE | PEN_MASK_ROTATION |
+                           PEN_MASK_TILT_X | PEN_MASK_TILT_Y;
+    info.penInfo.pressure = pressure;
+    info.penInfo.rotation = aRotation;
+    info.penInfo.tiltX = aTiltX;
+    info.penInfo.tiltY = aTiltY;
+
+    return InjectSyntheticPointerInput(sSyntheticPenDevice, &info, 1)
+               ? NS_OK
+               : NS_ERROR_UNEXPECTED;
+  });
+};
+
+bool nsWindow::HandleAppCommandMsg(const MSG& aAppCommandMsg,
+                                   LRESULT* aRetValue) {
+  ModifierKeyState modKeyState;
+  NativeKey nativeKey(this, aAppCommandMsg, modKeyState);
+  bool consumed = nativeKey.HandleAppCommandMessage();
+  *aRetValue = consumed ? 1 : 0;
+  return consumed;
+}
+
+#ifdef DEBUG
+nsresult nsWindow::SetHiDPIMode(bool aHiDPI) {
+  return WinUtils::SetHiDPIMode(aHiDPI);
+}
+
+nsresult nsWindow::RestoreHiDPIMode() { return WinUtils::RestoreHiDPIMode(); }
+#endif
+
+mozilla::Maybe<UINT> nsWindow::GetHiddenTaskbarEdge() {
+  HMONITOR windowMonitor = ::MonitorFromWindow(mWnd, MONITOR_DEFAULTTONEAREST);
+
+  // Check all four sides of our monitor for an appbar.  Skip any that aren't
+  // the system taskbar.
+  MONITORINFO mi;
+  mi.cbSize = sizeof(MONITORINFO);
+  ::GetMonitorInfo(windowMonitor, &mi);
+
+  APPBARDATA appBarData;
+  appBarData.cbSize = sizeof(appBarData);
+  appBarData.rc = mi.rcMonitor;
+  const auto kEdges = {ABE_BOTTOM, ABE_TOP, ABE_LEFT, ABE_RIGHT};
+  for (auto edge : kEdges) {
+    appBarData.uEdge = edge;
+    HWND appBarHwnd = (HWND)SHAppBarMessage(ABM_GETAUTOHIDEBAREX, &appBarData);
+    if (appBarHwnd) {
+      nsAutoString className;
+      if (WinUtils::GetClassName(appBarHwnd, className)) {
+        if (className.Equals(L"Shell_TrayWnd") ||
+            className.Equals(L"Shell_SecondaryTrayWnd")) {
+          return Some(edge);
+        }
+      }
+    }
+  }
+
+  return Nothing();
+}
+
+static nsSizeMode GetSizeModeForWindowFrame(HWND aWnd, bool aFullscreenMode) {
+  WINDOWPLACEMENT pl;
+  pl.length = sizeof(pl);
+  ::GetWindowPlacement(aWnd, &pl);
+
+  if (pl.showCmd == SW_SHOWMINIMIZED) {
+    return nsSizeMode_Minimized;
+  } else if (aFullscreenMode) {
+    return nsSizeMode_Fullscreen;
+  } else if (pl.showCmd == SW_SHOWMAXIMIZED) {
+    return nsSizeMode_Maximized;
+  } else {
+    return nsSizeMode_Normal;
+  }
+}
+
+static void ShowWindowWithMode(HWND aWnd, nsSizeMode aMode) {
+  // This will likely cause a callback to
+  // nsWindow::FrameState::{OnFrameChanging() and OnFrameChanged()}
+  switch (aMode) {
+    case nsSizeMode_Fullscreen:
+      ::ShowWindow(aWnd, SW_SHOW);
+      break;
+
+    case nsSizeMode_Maximized:
+      ::ShowWindow(aWnd, SW_MAXIMIZE);
+      break;
+
+    case nsSizeMode_Minimized:
+      ::ShowWindow(aWnd, SW_MINIMIZE);
+      break;
+
+    default:
+      // Don't call ::ShowWindow if we're trying to "restore" a window that is
+      // already in a normal state.  Prevents a bug where snapping to one side
+      // of the screen and then minimizing would cause Windows to forget our
+      // window's correct restored position/size.
+      if (GetCurrentShowCmd(aWnd) != SW_SHOWNORMAL) {
+        ::ShowWindow(aWnd, SW_RESTORE);
+      }
+  }
+}
+
+nsWindow::FrameState::FrameState(nsWindow* aWindow) : mWindow(aWindow) {}
+
+nsSizeMode nsWindow::FrameState::GetSizeMode() const { return mSizeMode; }
+
+void nsWindow::FrameState::CheckInvariant() const {
+  MOZ_ASSERT(mSizeMode >= 0 && mSizeMode < nsSizeMode_Invalid);
+  MOZ_ASSERT(mLastSizeMode >= 0 && mLastSizeMode < nsSizeMode_Invalid);
+  MOZ_ASSERT(mPreFullscreenSizeMode >= 0 &&
+             mPreFullscreenSizeMode < nsSizeMode_Invalid);
+  MOZ_ASSERT(mWindow);
+
+  // We should never observe fullscreen sizemode unless fullscreen is enabled
+  MOZ_ASSERT_IF(mSizeMode == nsSizeMode_Fullscreen, mFullscreenMode);
+  MOZ_ASSERT_IF(!mFullscreenMode, mSizeMode != nsSizeMode_Fullscreen);
+
+  // Something went wrong if we somehow saved fullscreen mode when we are
+  // changing into fullscreen mode
+  MOZ_ASSERT(mPreFullscreenSizeMode != nsSizeMode_Fullscreen);
+}
+
+void nsWindow::FrameState::ConsumePreXULSkeletonState(bool aWasMaximized) {
+  mSizeMode = aWasMaximized ? nsSizeMode_Maximized : nsSizeMode_Normal;
+}
+
+void nsWindow::FrameState::EnsureSizeMode(nsSizeMode aMode,
+                                          DoShowWindow aDoShowWindow) {
+  if (mSizeMode == aMode) {
+    return;
+  }
+
+  if (StaticPrefs::widget_windows_fullscreen_remind_taskbar()) {
+    // If we're unminimizing a window, asynchronously notify the taskbar after
+    // the message has been processed. This redundant notification works around
+    // a race condition in explorer.exe. (See bug 1835851, or comments in
+    // TaskbarConcealer.)
+    //
+    // Note that we notify regardless of `aMode`: unminimizing a non-fullscreen
+    // window can also affect the correct taskbar state, yet fail to affect the
+    // current taskbar state.
+    if (mSizeMode == nsSizeMode_Minimized) {
+      ::PostMessage(mWindow->mWnd, MOZ_WM_FULLSCREEN_STATE_UPDATE, 0, 0);
+    }
+  }
+
+  if (aMode == nsSizeMode_Fullscreen) {
+    EnsureFullscreenMode(true, aDoShowWindow);
+    MOZ_ASSERT(mSizeMode == nsSizeMode_Fullscreen);
+  } else if (mSizeMode == nsSizeMode_Fullscreen && aMode == nsSizeMode_Normal) {
+    // If we are in fullscreen mode, minimize should work like normal and
+    // return us to fullscreen mode when unminimized. Maximize isn't really
+    // available and won't do anything. "Restore" should do the same thing as
+    // requesting to end fullscreen.
+    EnsureFullscreenMode(false, aDoShowWindow);
+  } else {
+    SetSizeModeInternal(aMode, aDoShowWindow);
+  }
+}
+
+void nsWindow::FrameState::EnsureFullscreenMode(bool aFullScreen,
+                                                DoShowWindow aDoShowWindow) {
+  const bool changed = aFullScreen != mFullscreenMode;
+  if (changed && aFullScreen) {
+    // Save the size mode from before fullscreen.
+    mPreFullscreenSizeMode = mSizeMode;
+  }
+  mFullscreenMode = aFullScreen;
+  if (changed || aFullScreen) {
+    // NOTE(emilio): When minimizing a fullscreen window we remain with
+    // mFullscreenMode = true, but mSizeMode = nsSizeMode_Minimized. We need to
+    // make sure to call SetSizeModeInternal even if mFullscreenMode didn't
+    // change, to ensure we actually end up with a fullscreen sizemode when
+    // restoring a window from that state.
+    SetSizeModeInternal(
+        aFullScreen ? nsSizeMode_Fullscreen : mPreFullscreenSizeMode,
+        aDoShowWindow);
+  }
+}
+
+void nsWindow::FrameState::OnFrameChanging() {
+  const nsSizeMode newSizeMode =
+      GetSizeModeForWindowFrame(mWindow->mWnd, mFullscreenMode);
+  EnsureSizeMode(newSizeMode);
+  mWindow->UpdateNonClientMargins(false);
+}
+
+void nsWindow::FrameState::OnFrameChanged() {
+  // We don't want to perform the ShowWindow ourselves if we're on the frame
+  // changed message. Windows has done the frame change for us, and we take care
+  // of activating as needed. We also don't want to potentially trigger
+  // more focus / restore. Among other things, this addresses a bug on Win7
+  // related to window docking. (bug 489258)
+  const auto newSizeMode =
+      GetSizeModeForWindowFrame(mWindow->mWnd, mFullscreenMode);
+  EnsureSizeMode(newSizeMode, DoShowWindow::No);
+
+  // If window was restored, activate the window now to get correct attributes.
+  if (mWindow->mIsVisible && mWindow->IsForegroundWindow() &&
+      mLastSizeMode == nsSizeMode_Minimized &&
+      mSizeMode != nsSizeMode_Minimized) {
+    mWindow->DispatchFocusToTopLevelWindow(true);
+  }
+  mLastSizeMode = mSizeMode;
+}
+
+static void MaybeLogSizeMode(nsSizeMode aMode) {
+#ifdef WINSTATE_DEBUG_OUTPUT
+  MOZ_LOG(gWindowsLog, LogLevel::Info, ("*** SizeMode: %d\n", int(aMode)));
+#endif
+}
+
+void nsWindow::FrameState::SetSizeModeInternal(nsSizeMode aMode,
+                                               DoShowWindow aDoShowWindow) {
+  if (mSizeMode == aMode) {
+    return;
+  }
+
+  const auto oldSizeMode = mSizeMode;
+  const bool fullscreenChange =
+      mSizeMode == nsSizeMode_Fullscreen || aMode == nsSizeMode_Fullscreen;
+  const bool fullscreen = aMode == nsSizeMode_Fullscreen;
+
+  mLastSizeMode = mSizeMode;
+  mSizeMode = aMode;
+
+  MaybeLogSizeMode(mSizeMode);
+
+  if (bool(aDoShowWindow) && mWindow->mIsVisible) {
+    ShowWindowWithMode(mWindow->mWnd, aMode);
+  }
+
+  mWindow->UpdateNonClientMargins(false);
+
+  if (fullscreenChange) {
+    mWindow->OnFullscreenChanged(oldSizeMode, fullscreen);
+  }
+
+  mWindow->OnSizeModeChange();
+}
+
+void nsWindow::ContextMenuPreventer::Update(
+    const WidgetMouseEvent& aEvent,
+    const nsIWidget::ContentAndAPZEventStatus& aEventStatus) {
+  mNeedsToPreventContextMenu =
+      aEvent.mMessage == eMouseUp &&
+      aEvent.mButton == MouseButton::eSecondary &&
+      aEvent.mInputSource == MouseEvent_Binding::MOZ_SOURCE_MOUSE &&
+      aEventStatus.mApzStatus == nsEventStatus_eConsumeNoDefault;
+}
diff --git a/widget/windows/nsWindow.h b/widget/windows/nsWindow.h
new file mode 100644
index 0000000000..c75c9d174d
--- /dev/null
+++ b/widget/windows/nsWindow.h
@@ -0,0 +1,905 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_WINDOWS_NSWINDOW_H_
+#define WIDGET_WINDOWS_NSWINDOW_H_
+
+/*
+ * nsWindow - Native window management and event handling.
+ */
+
+#include "mozilla/RefPtr.h"
+#include "nsBaseWidget.h"
+#include "CompositorWidget.h"
+#include "mozilla/EventForwards.h"
+#include "nsClassHashtable.h"
+#include <windows.h>
+#include "touchinjection_sdk80.h"
+#include "nsdefs.h"
+#include "nsUserIdleService.h"
+#include "nsToolkit.h"
+#include "nsString.h"
+#include "nsTArray.h"
+#include "gfxWindowsPlatform.h"
+#include "gfxWindowsSurface.h"
+#include "nsWindowDbg.h"
+#include "cairo.h"
+#include "nsRegion.h"
+#include "mozilla/EnumeratedArray.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/MouseEvents.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/webrender/WebRenderTypes.h"
+#include "mozilla/dom/MouseEventBinding.h"
+#include "mozilla/DataMutex.h"
+#include "mozilla/UniquePtr.h"
+#include "nsMargin.h"
+#include "nsRegionFwd.h"
+
+#include "nsWinGesture.h"
+#include "WinPointerEvents.h"
+#include "WinUtils.h"
+#include "WindowHook.h"
+#include "TaskbarWindowPreview.h"
+
+#ifdef ACCESSIBILITY
+#  include "oleacc.h"
+#  include "mozilla/a11y/LocalAccessible.h"
+#endif
+
+#include "nsUXThemeData.h"
+#include "nsIUserIdleServiceInternal.h"
+
+#include "IMMHandler.h"
+#include "CheckInvariantWrapper.h"
+
+/**
+ * Forward class definitions
+ */
+
+class nsNativeDragTarget;
+class nsIRollupListener;
+class imgIContainer;
+
+namespace mozilla {
+class WidgetMouseEvent;
+namespace widget {
+class NativeKey;
+class InProcessWinCompositorWidget;
+struct MSGResult;
+class DirectManipulationOwner;
+}  // namespace widget
+}  // namespace mozilla
+
+/**
+ * Forward Windows-internal definitions of otherwise incomplete ones provided by
+ * the SDK.
+ */
+const CLSID CLSID_ImmersiveShell = {
+    0xC2F03A33,
+    0x21F5,
+    0x47FA,
+    {0xB4, 0xBB, 0x15, 0x63, 0x62, 0xA2, 0xF2, 0x39}};
+
+/**
+ * Native WIN32 window wrapper.
+ */
+
+class nsWindow final : public nsBaseWidget {
+ public:
+  using WindowHook = mozilla::widget::WindowHook;
+  using IMEContext = mozilla::widget::IMEContext;
+  using WidgetEventTime = mozilla::WidgetEventTime;
+
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(nsWindow, nsBaseWidget)
+
+  explicit nsWindow(bool aIsChildWindow = false);
+
+  void SendAnAPZEvent(mozilla::InputData& aEvent);
+
+  /*
+   * Init a standard gecko event for this widget.
+   * @param aEvent the event to initialize.
+   * @param aPoint message position in physical coordinates.
+   */
+  void InitEvent(mozilla::WidgetGUIEvent& aEvent,
+                 LayoutDeviceIntPoint* aPoint = nullptr);
+
+  /*
+   * Returns WidgetEventTime instance which is initialized with current message
+   * time.
+   */
+  WidgetEventTime CurrentMessageWidgetEventTime() const;
+
+  /*
+   * Dispatch a gecko keyboard event for this widget. This
+   * is called by KeyboardLayout to dispatch gecko events.
+   * Returns true if it's consumed.  Otherwise, false.
+   */
+  bool DispatchKeyboardEvent(mozilla::WidgetKeyboardEvent* aEvent);
+
+  /*
+   * Dispatch a gecko wheel event for this widget. This
+   * is called by ScrollHandler to dispatch gecko events.
+   * Returns true if it's consumed.  Otherwise, false.
+   */
+  bool DispatchWheelEvent(mozilla::WidgetWheelEvent* aEvent);
+
+  /*
+   * Dispatch a gecko content command event for this widget. This
+   * is called by ScrollHandler to dispatch gecko events.
+   * Returns true if it's consumed.  Otherwise, false.
+   */
+  bool DispatchContentCommandEvent(mozilla::WidgetContentCommandEvent* aEvent);
+
+  /*
+   * Return the parent window, if it exists.
+   */
+  nsWindow* GetParentWindowBase(bool aIncludeOwner);
+
+  /*
+   * Return true if this is a top level widget.
+   */
+  bool IsTopLevelWidget() { return mIsTopWidgetWindow; }
+
+  // nsIWidget interface
+  using nsBaseWidget::Create;  // for Create signature not overridden here
+  [[nodiscard]] nsresult Create(nsIWidget* aParent,
+                                nsNativeWidget aNativeParent,
+                                const LayoutDeviceIntRect& aRect,
+                                InitData* aInitData = nullptr) override;
+  void Destroy() override;
+  void SetParent(nsIWidget* aNewParent) override;
+  nsIWidget* GetParent(void) override;
+  float GetDPI() override;
+  double GetDefaultScaleInternal() override;
+  int32_t LogToPhys(double aValue);
+  mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale() override {
+    if (mozilla::widget::WinUtils::IsPerMonitorDPIAware()) {
+      return mozilla::DesktopToLayoutDeviceScale(1.0);
+    } else {
+      return mozilla::DesktopToLayoutDeviceScale(GetDefaultScaleInternal());
+    }
+  }
+
+  void Show(bool aState) override;
+  bool IsVisible() const override;
+  void ConstrainPosition(DesktopIntPoint&) override;
+  void SetSizeConstraints(const SizeConstraints& aConstraints) override;
+  void LockAspectRatio(bool aShouldLock) override;
+  const SizeConstraints GetSizeConstraints() override;
+  void SetInputRegion(const InputRegion&) override;
+  void Move(double aX, double aY) override;
+  void Resize(double aWidth, double aHeight, bool aRepaint) override;
+  void Resize(double aX, double aY, double aWidth, double aHeight,
+              bool aRepaint) override;
+  mozilla::Maybe<bool> IsResizingNativeWidget() override;
+  void PlaceBehind(nsTopLevelWidgetZPlacement aPlacement, nsIWidget* aWidget,
+                   bool aActivate) override;
+  void SetSizeMode(nsSizeMode aMode) override;
+  nsSizeMode SizeMode() override;
+  void GetWorkspaceID(nsAString& workspaceID) override;
+  void MoveToWorkspace(const nsAString& workspaceID) override;
+  void SuppressAnimation(bool aSuppress) override;
+  void Enable(bool aState) override;
+  bool IsEnabled() const override;
+  void SetFocus(Raise, mozilla::dom::CallerType aCallerType) override;
+  LayoutDeviceIntRect GetBounds() override;
+  LayoutDeviceIntRect GetScreenBounds() override;
+  [[nodiscard]] nsresult GetRestoredBounds(LayoutDeviceIntRect& aRect) override;
+  LayoutDeviceIntRect GetClientBounds() override;
+  LayoutDeviceIntPoint GetClientOffset() override;
+  void SetBackgroundColor(const nscolor& aColor) override;
+  void SetCursor(const Cursor&) override;
+  bool PrepareForFullscreenTransition(nsISupports** aData) override;
+  void PerformFullscreenTransition(FullscreenTransitionStage aStage,
+                                   uint16_t aDuration, nsISupports* aData,
+                                   nsIRunnable* aCallback) override;
+  void CleanupFullscreenTransition() override;
+  nsresult MakeFullScreen(bool aFullScreen) override;
+  void HideWindowChrome(bool aShouldHide) override;
+  void Invalidate(bool aEraseBackground = false, bool aUpdateNCArea = false,
+                  bool aIncludeChildren = false);
+  void Invalidate(const LayoutDeviceIntRect& aRect) override;
+  void* GetNativeData(uint32_t aDataType) override;
+  void FreeNativeData(void* data, uint32_t aDataType) override;
+  nsresult SetTitle(const nsAString& aTitle) override;
+  void SetIcon(const nsAString& aIconSpec) override;
+  LayoutDeviceIntPoint WidgetToScreenOffset() override;
+  LayoutDeviceIntMargin ClientToWindowMargin() override;
+  nsresult DispatchEvent(mozilla::WidgetGUIEvent* aEvent,
+                         nsEventStatus& aStatus) override;
+  void EnableDragDrop(bool aEnable) override;
+  void CaptureMouse(bool aCapture);
+  void CaptureRollupEvents(bool aDoCapture) override;
+  [[nodiscard]] nsresult GetAttention(int32_t aCycleCount) override;
+  bool HasPendingInputEvent() override;
+  WindowRenderer* GetWindowRenderer() override;
+  void SetCompositorWidgetDelegate(CompositorWidgetDelegate* delegate) override;
+  [[nodiscard]] nsresult OnDefaultButtonLoaded(
+      const LayoutDeviceIntRect& aButtonRect) override;
+  nsresult SynthesizeNativeKeyEvent(int32_t aNativeKeyboardLayout,
+                                    int32_t aNativeKeyCode,
+                                    uint32_t aModifierFlags,
+                                    const nsAString& aCharacters,
+                                    const nsAString& aUnmodifiedCharacters,
+                                    nsIObserver* aObserver) override;
+  nsresult SynthesizeNativeMouseEvent(LayoutDeviceIntPoint aPoint,
+                                      NativeMouseMessage aNativeMessage,
+                                      mozilla::MouseButton aButton,
+                                      nsIWidget::Modifiers aModifierFlags,
+                                      nsIObserver* aObserver) override;
+
+  nsresult SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
+                                     nsIObserver* aObserver) override {
+    return SynthesizeNativeMouseEvent(
+        aPoint, NativeMouseMessage::Move, mozilla::MouseButton::eNotPressed,
+        nsIWidget::Modifiers::NO_MODIFIERS, aObserver);
+  }
+
+  nsresult SynthesizeNativeMouseScrollEvent(
+      LayoutDeviceIntPoint aPoint, uint32_t aNativeMessage, double aDeltaX,
+      double aDeltaY, double aDeltaZ, uint32_t aModifierFlags,
+      uint32_t aAdditionalFlags, nsIObserver* aObserver) override;
+
+  nsresult SynthesizeNativeTouchpadPan(TouchpadGesturePhase aEventPhase,
+                                       LayoutDeviceIntPoint aPoint,
+                                       double aDeltaX, double aDeltaY,
+                                       int32_t aModifierFlagsn,
+                                       nsIObserver* aObserver) override;
+
+  void SetInputContext(const InputContext& aContext,
+                       const InputContextAction& aAction) override;
+  InputContext GetInputContext() override;
+  TextEventDispatcherListener* GetNativeTextEventDispatcherListener() override;
+  void SetTransparencyMode(TransparencyMode aMode) override;
+  TransparencyMode GetTransparencyMode() override;
+  nsresult SetNonClientMargins(const LayoutDeviceIntMargin&) override;
+  void SetResizeMargin(mozilla::LayoutDeviceIntCoord aResizeMargin) override;
+  void UpdateWindowDraggingRegion(
+      const LayoutDeviceIntRegion& aRegion) override;
+
+  uint32_t GetMaxTouchPoints() const override;
+  void SetWindowClass(const nsAString& xulWinType, const nsAString& xulWinClass,
+                      const nsAString& xulWinName) override;
+
+  /**
+   * Event helpers
+   */
+  bool DispatchMouseEvent(mozilla::EventMessage aEventMessage, WPARAM wParam,
+                          LPARAM lParam, bool aIsContextMenuKey,
+                          int16_t aButton, uint16_t aInputSource,
+                          WinPointerInfo* aPointerInfo = nullptr,
+                          bool aIgnoreAPZ = false);
+  void DispatchPendingEvents();
+  void DispatchCustomEvent(const nsString& eventName);
+
+#ifdef ACCESSIBILITY
+  /**
+   * Return an accessible associated with the window.
+   */
+  mozilla::a11y::LocalAccessible* GetAccessible();
+#endif  // ACCESSIBILITY
+
+  /**
+   * Window utilities
+   */
+  nsWindow* GetTopLevelWindow(bool aStopOnDialogOrPopup);
+  WNDPROC GetPrevWindowProc() { return mPrevWndProc.valueOr(nullptr); }
+  WindowHook& GetWindowHook() { return mWindowHook; }
+  nsWindow* GetParentWindow(bool aIncludeOwner);
+
+  /**
+   * Misc.
+   */
+  bool WidgetTypeSupportsAcceleration() override;
+
+  void ForcePresent();
+  bool TouchEventShouldStartDrag(mozilla::EventMessage aEventMessage,
+                                 LayoutDeviceIntPoint aEventPoint);
+
+  void SetSmallIcon(HICON aIcon);
+  void SetBigIcon(HICON aIcon);
+  void SetSmallIconNoData();
+  void SetBigIconNoData();
+
+  static void SetIsRestoringSession(const bool aIsRestoringSession) {
+    sIsRestoringSession = aIsRestoringSession;
+  }
+
+  bool IsRTL() const { return mIsRTL; }
+
+  /**
+   * AssociateDefaultIMC() associates or disassociates the default IMC for
+   * the window.
+   *
+   * @param aAssociate    TRUE, associates the default IMC with the window.
+   *                      Otherwise, disassociates the default IMC from the
+   *                      window.
+   * @return              TRUE if this method associated the default IMC with
+   *                      disassociated window or disassociated the default IMC
+   *                      from associated window.
+   *                      Otherwise, i.e., if this method did nothing actually,
+   *                      FALSE.
+   */
+  bool AssociateDefaultIMC(bool aAssociate);
+
+  bool HasTaskbarIconBeenCreated() { return mHasTaskbarIconBeenCreated; }
+  // Called when either the nsWindow or an nsITaskbarTabPreview receives the
+  // noticiation that this window has its icon placed on the taskbar.
+  void SetHasTaskbarIconBeenCreated(bool created = true) {
+    mHasTaskbarIconBeenCreated = created;
+  }
+
+  // Getter/setter for the nsITaskbarWindowPreview for this nsWindow
+  already_AddRefed<nsITaskbarWindowPreview> GetTaskbarPreview() {
+    nsCOMPtr<nsITaskbarWindowPreview> preview(
+        do_QueryReferent(mTaskbarPreview));
+    return preview.forget();
+  }
+  void SetTaskbarPreview(nsITaskbarWindowPreview* preview) {
+    mTaskbarPreview = do_GetWeakReference(preview);
+  }
+
+  void ReparentNativeWidget(nsIWidget* aNewParent) override;
+
+  // Open file picker tracking
+  void PickerOpen();
+  void PickerClosed();
+
+  bool DestroyCalled() { return mDestroyCalled; }
+
+  bool IsPopup();
+  bool ShouldUseOffMainThreadCompositing() override;
+
+  const IMEContext& DefaultIMC() const { return mDefaultIMC; }
+
+  void GetCompositorWidgetInitData(
+      mozilla::widget::CompositorWidgetInitData* aInitData) override;
+  bool IsTouchWindow() const { return mTouchWindow; }
+  bool SynchronouslyRepaintOnResize() override;
+  void MaybeDispatchInitialFocusEvent() override;
+
+  void LocalesChanged() override;
+
+  void NotifyOcclusionState(mozilla::widget::OcclusionState aState) override;
+  void MaybeEnableWindowOcclusion(bool aEnable);
+
+  /*
+   * Return the HWND or null for this widget.
+   */
+  HWND GetWindowHandle() {
+    return static_cast<HWND>(GetNativeData(NS_NATIVE_WINDOW));
+  }
+
+  /*
+   * Touch input injection apis
+   */
+  nsresult SynthesizeNativeTouchPoint(uint32_t aPointerId,
+                                      TouchPointerState aPointerState,
+                                      LayoutDeviceIntPoint aPoint,
+                                      double aPointerPressure,
+                                      uint32_t aPointerOrientation,
+                                      nsIObserver* aObserver) override;
+  nsresult ClearNativeTouchSequence(nsIObserver* aObserver) override;
+
+  nsresult SynthesizeNativePenInput(uint32_t aPointerId,
+                                    TouchPointerState aPointerState,
+                                    LayoutDeviceIntPoint aPoint,
+                                    double aPressure, uint32_t aRotation,
+                                    int32_t aTiltX, int32_t aTiltY,
+                                    int32_t aButton,
+                                    nsIObserver* aObserver) override;
+
+  /*
+   * WM_APPCOMMAND common handler.
+   * Sends events via NativeKey::HandleAppCommandMessage().
+   */
+  bool HandleAppCommandMsg(const MSG& aAppCommandMsg, LRESULT* aRetValue);
+
+  const InputContext& InputContextRef() const { return mInputContext; }
+
+ private:
+  using TimeStamp = mozilla::TimeStamp;
+  using TimeDuration = mozilla::TimeDuration;
+  using TaskbarWindowPreview = mozilla::widget::TaskbarWindowPreview;
+  using NativeKey = mozilla::widget::NativeKey;
+  using MSGResult = mozilla::widget::MSGResult;
+  using PlatformCompositorWidgetDelegate =
+      mozilla::widget::PlatformCompositorWidgetDelegate;
+
+  struct Desktop {
+    // Cached GUID of the virtual desktop this window should be on.
+    // This value may be stale.
+    nsString mID;
+    bool mUpdateIsQueued = false;
+  };
+
+  class PointerInfo {
+   public:
+    enum class PointerType : uint8_t {
+      TOUCH,
+      PEN,
+    };
+
+    PointerInfo(int32_t aPointerId, LayoutDeviceIntPoint& aPoint,
+                PointerType aType)
+        : mPointerId(aPointerId), mPosition(aPoint), mType(aType) {}
+
+    int32_t mPointerId;
+    LayoutDeviceIntPoint mPosition;
+    PointerType mType;
+  };
+
+  class FrameState {
+   public:
+    explicit FrameState(nsWindow* aWindow);
+
+    void ConsumePreXULSkeletonState(bool aWasMaximized);
+
+    // Whether we should call ShowWindow with the relevant size mode if needed.
+    // We want to avoid that when Windows is already performing the change for
+    // us (via the SWP_FRAMECHANGED messages).
+    enum class DoShowWindow : bool { No, Yes };
+
+    void EnsureSizeMode(nsSizeMode, DoShowWindow = DoShowWindow::Yes);
+    void EnsureFullscreenMode(bool, DoShowWindow = DoShowWindow::Yes);
+    void OnFrameChanging();
+    void OnFrameChanged();
+
+    nsSizeMode GetSizeMode() const;
+
+    void CheckInvariant() const;
+
+   private:
+    void SetSizeModeInternal(nsSizeMode, DoShowWindow);
+
+    nsSizeMode mSizeMode = nsSizeMode_Normal;
+    // XXX mLastSizeMode is rather bizarre and needs some documentation.
+    nsSizeMode mLastSizeMode = nsSizeMode_Normal;
+    // The old size mode before going into fullscreen mode. This should never
+    // be nsSizeMode_Fullscreen.
+    nsSizeMode mPreFullscreenSizeMode = nsSizeMode_Normal;
+    // Whether we're in fullscreen. We need to keep this state out of band,
+    // rather than just using mSizeMode, because a window can be minimized
+    // while fullscreen, and we don't store the fullscreen state anywhere else.
+    bool mFullscreenMode = false;
+    nsWindow* mWindow;
+  };
+
+  // Manager for taskbar-hiding. No persistent state.
+  class TaskbarConcealer;
+
+  // A magic number to identify the FAKETRACKPOINTSCROLLABLE window created
+  // when the trackpoint hack is enabled.
+  enum { eFakeTrackPointScrollableID = 0x46545053 };
+
+  // Used for displayport suppression during window resize
+  enum ResizeState { NOT_RESIZING, IN_SIZEMOVE, RESIZING, MOVING };
+
+  ~nsWindow() override;
+
+  void WindowUsesOMTC() override;
+  void RegisterTouchWindow() override;
+
+  /**
+   * Callbacks
+   */
+  static LRESULT CALLBACK WindowProc(HWND hWnd, UINT msg, WPARAM wParam,
+                                     LPARAM lParam);
+  static LRESULT CALLBACK WindowProcInternal(HWND hWnd, UINT msg, WPARAM wParam,
+                                             LPARAM lParam);
+
+  static BOOL CALLBACK DispatchStarvedPaints(HWND aTopWindow, LPARAM aMsg);
+  static BOOL CALLBACK RegisterTouchForDescendants(HWND aTopWindow,
+                                                   LPARAM aMsg);
+  static BOOL CALLBACK UnregisterTouchForDescendants(HWND aTopWindow,
+                                                     LPARAM aMsg);
+  static LRESULT CALLBACK MozSpecialMsgFilter(int code, WPARAM wParam,
+                                              LPARAM lParam);
+  static LRESULT CALLBACK MozSpecialWndProc(int code, WPARAM wParam,
+                                            LPARAM lParam);
+  static LRESULT CALLBACK MozSpecialMouseProc(int code, WPARAM wParam,
+                                              LPARAM lParam);
+  static VOID CALLBACK HookTimerForPopups(HWND hwnd, UINT uMsg, UINT idEvent,
+                                          DWORD dwTime);
+
+  /**
+   * Window utilities
+   */
+  LPARAM lParamToScreen(LPARAM lParam);
+  LPARAM lParamToClient(LPARAM lParam);
+
+  WPARAM wParamFromGlobalMouseState();
+
+  bool AssociateWithNativeWindow();
+  void DissociateFromNativeWindow();
+  bool CanTakeFocus();
+  bool UpdateNonClientMargins(bool aReflowWindow = true);
+  void UpdateDarkModeToolbar();
+  void UpdateGetWindowInfoCaptionStatus(bool aActiveCaption);
+  void ResetLayout();
+  void InvalidateNonClientRegion();
+  static const wchar_t* GetMainWindowClass();
+  HWND GetOwnerWnd() const { return ::GetWindow(mWnd, GW_OWNER); }
+  bool IsOwnerForegroundWindow() const {
+    HWND owner = GetOwnerWnd();
+    return owner && owner == ::GetForegroundWindow();
+  }
+  bool IsForegroundWindow() const { return mWnd == ::GetForegroundWindow(); }
+  bool IsPopup() const { return mWindowType == WindowType::Popup; }
+  bool IsCloaked() const { return mIsCloaked; }
+
+  /**
+   * Event processing helpers
+   */
+  HWND GetTopLevelForFocus(HWND aCurWnd);
+  void DispatchFocusToTopLevelWindow(bool aIsActivate);
+  bool DispatchStandardEvent(mozilla::EventMessage aMsg);
+  void RelayMouseEvent(UINT aMsg, WPARAM wParam, LPARAM lParam);
+  bool ProcessMessage(UINT msg, WPARAM& wParam, LPARAM& lParam,
+                      LRESULT* aRetValue);
+  // We wrap this in ProcessMessage so we can log the return value
+  bool ProcessMessageInternal(UINT msg, WPARAM& wParam, LPARAM& lParam,
+                              LRESULT* aRetValue);
+  bool ExternalHandlerProcessMessage(UINT aMessage, WPARAM& aWParam,
+                                     LPARAM& aLParam, MSGResult& aResult);
+  LRESULT ProcessCharMessage(const MSG& aMsg, bool* aEventDispatched);
+  LRESULT ProcessKeyUpMessage(const MSG& aMsg, bool* aEventDispatched);
+  LRESULT ProcessKeyDownMessage(const MSG& aMsg, bool* aEventDispatched);
+  static bool EventIsInsideWindow(
+      nsWindow* aWindow,
+      mozilla::Maybe<POINT> aEventPoint = mozilla::Nothing());
+  static void PostSleepWakeNotification(const bool aIsSleepMode);
+  int32_t ClientMarginHitTestPoint(int32_t mx, int32_t my);
+  void SetWindowButtonRect(WindowButtonType aButtonType,
+                           const LayoutDeviceIntRect& aClientRect) override {
+    mWindowBtnRect[aButtonType] = aClientRect;
+  }
+  TimeStamp GetMessageTimeStamp(LONG aEventTime) const;
+  static void UpdateFirstEventTime(DWORD aEventTime);
+  void FinishLiveResizing(ResizeState aNewState);
+  mozilla::Maybe<mozilla::PanGestureInput> ConvertTouchToPanGesture(
+      const mozilla::MultiTouchInput& aTouchInput, PTOUCHINPUT aOriginalEvent);
+  void DispatchTouchOrPanGestureInput(mozilla::MultiTouchInput& aTouchInput,
+                                      PTOUCHINPUT aOSEvent);
+
+  /**
+   * Event handlers
+   */
+  void OnDestroy() override;
+  bool OnResize(const LayoutDeviceIntSize& aSize);
+  void OnSizeModeChange();
+  bool OnGesture(WPARAM wParam, LPARAM lParam);
+  bool OnTouch(WPARAM wParam, LPARAM lParam);
+  bool OnHotKey(WPARAM wParam, LPARAM lParam);
+  bool OnPaint(uint32_t aNestingLevel);
+  void OnWindowPosChanging(WINDOWPOS* info);
+  void OnWindowPosChanged(WINDOWPOS* wp);
+  void OnSysColorChanged();
+  void OnDPIChanged(int32_t x, int32_t y, int32_t width, int32_t height);
+  bool OnPointerEvents(UINT msg, WPARAM wParam, LPARAM lParam);
+
+  /**
+   * Function that registers when the user has been active (used for detecting
+   * when the user is idle).
+   */
+  void UserActivity();
+
+  int32_t GetHeight(int32_t aProposedHeight);
+
+  DWORD WindowStyle();
+  DWORD WindowExStyle();
+
+  static const wchar_t* ChooseWindowClass(WindowType);
+  // This method registers the given window class, and returns the class name.
+  static const wchar_t* RegisterWindowClass(const wchar_t* aClassName,
+                                            UINT aExtraStyle, LPWSTR aIconID);
+
+  /**
+   * Popup hooks
+   */
+  static void ScheduleHookTimer(HWND aWnd, UINT aMsgId);
+  static void RegisterSpecialDropdownHooks();
+  static void UnregisterSpecialDropdownHooks();
+  static bool GetPopupsToRollup(
+      nsIRollupListener* aRollupListener, uint32_t* aPopupsToRollup,
+      mozilla::Maybe<POINT> aEventPoint = mozilla::Nothing());
+  static bool NeedsToHandleNCActivateDelayed(HWND aWnd);
+  static bool DealWithPopups(HWND inWnd, UINT inMsg, WPARAM inWParam,
+                             LPARAM inLParam, LRESULT* outResult);
+
+  /**
+   * Window transparency helpers
+   */
+  void SetWindowTranslucencyInner(TransparencyMode aMode);
+  TransparencyMode GetWindowTranslucencyInner() const {
+    return mTransparencyMode;
+  }
+  bool IsSimulatedClientArea(int32_t clientX, int32_t clientY);
+  bool IsWindowButton(int32_t hitTestResult);
+
+  bool DispatchTouchEventFromWMPointer(UINT msg, LPARAM aLParam,
+                                       const WinPointerInfo& aPointerInfo,
+                                       mozilla::MouseButton aButton);
+
+  static bool IsAsyncResponseEvent(UINT aMsg, LRESULT& aResult);
+  void IPCWindowProcHandler(UINT& msg, WPARAM& wParam, LPARAM& lParam);
+
+  /**
+   * Misc.
+   */
+  void StopFlashing();
+  static HWND WindowAtMouse();
+  static bool IsTopLevelMouseExit(HWND aWnd);
+  LayoutDeviceIntRegion GetRegionToPaint(bool aForceFullRepaint, PAINTSTRUCT ps,
+                                         HDC aDC);
+  nsIWidgetListener* GetPaintListener();
+
+  void CreateCompositor() override;
+  void DestroyCompositor() override;
+  void RequestFxrOutput() override;
+
+  void RecreateDirectManipulationIfNeeded();
+  void ResizeDirectManipulationViewport();
+  void DestroyDirectManipulation();
+
+  bool NeedsToTrackWindowOcclusionState();
+
+  void AsyncUpdateWorkspaceID(Desktop& aDesktop);
+
+  // See bug 603793
+  static bool HasBogusPopupsDropShadowOnMultiMonitor();
+
+  static void InitMouseWheelScrollData();
+
+  void ChangedDPI();
+
+  static bool InitTouchInjection();
+
+  bool InjectTouchPoint(uint32_t aId, LayoutDeviceIntPoint& aPoint,
+                        POINTER_FLAGS aFlags, uint32_t aPressure = 1024,
+                        uint32_t aOrientation = 90);
+
+  void OnFullscreenChanged(nsSizeMode aOldSizeMode, bool aFullScreen);
+  void TryDwmResizeHack();
+
+  static void OnCloakEvent(HWND aWnd, bool aCloaked);
+  void OnCloakChanged(bool aCloaked);
+
+#ifdef DEBUG
+  virtual nsresult SetHiDPIMode(bool aHiDPI) override;
+  virtual nsresult RestoreHiDPIMode() override;
+#endif
+
+  // Get the orientation of the hidden taskbar, on the screen that this window
+  // is on, or Nothing if taskbar isn't hidden.
+  mozilla::Maybe<UINT> GetHiddenTaskbarEdge();
+
+  static bool sTouchInjectInitialized;
+  static InjectTouchInputPtr sInjectTouchFuncPtr;
+  static uint32_t sInstanceCount;
+  static nsWindow* sCurrentWindow;
+  static bool sIsOleInitialized;
+  static Cursor sCurrentCursor;
+  static bool sJustGotDeactivate;
+  static bool sJustGotActivate;
+  static bool sIsInMouseCapture;
+  static bool sIsRestoringSession;
+
+  // Message postponement hack. See the definition-site of
+  // WndProcUrgentInvocation::sDepth for details.
+  struct MOZ_STACK_CLASS WndProcUrgentInvocation {
+    struct Marker {
+      Marker() { ++sDepth; }
+      ~Marker() { --sDepth; }
+    };
+    inline static bool IsActive() { return sDepth > 0; }
+    static size_t sDepth;
+  };
+
+  // Hook Data Members for Dropdowns. sProcessHook Tells the
+  // hook methods whether they should be processing the hook
+  // messages.
+  static HHOOK sMsgFilterHook;
+  static HHOOK sCallProcHook;
+  static HHOOK sCallMouseHook;
+  static bool sProcessHook;
+  static UINT sRollupMsgId;
+  static HWND sRollupMsgWnd;
+  static UINT sHookTimerId;
+
+  // Used to prevent dispatching mouse events that do not originate from user
+  // input.
+  static POINT sLastMouseMovePoint;
+
+  nsClassHashtable<nsUint32HashKey, PointerInfo> mActivePointers;
+
+  // This is used by SynthesizeNativeTouchPoint to maintain state between
+  // multiple synthesized points, in the case where we can't call InjectTouch
+  // directly.
+  mozilla::UniquePtr<mozilla::MultiTouchInput> mSynthesizedTouchInput;
+
+  InputContext mInputContext;
+
+  nsCOMPtr<nsIWidget> mParent;
+  nsIntSize mLastSize = nsIntSize(0, 0);
+  nsIntPoint mLastPoint;
+  HWND mWnd = nullptr;
+  HWND mTransitionWnd = nullptr;
+  mozilla::Maybe<WNDPROC> mPrevWndProc;
+  HBRUSH mBrush;
+  IMEContext mDefaultIMC;
+  HDEVNOTIFY mDeviceNotifyHandle = nullptr;
+  bool mIsTopWidgetWindow = false;
+  bool mInDtor = false;
+  bool mIsVisible = false;
+  bool mIsCloaked = false;
+  bool mTouchWindow = false;
+  bool mDisplayPanFeedback = false;
+  bool mHideChrome = false;
+  bool mIsRTL;
+  bool mMousePresent = false;
+  bool mSimulatedClientArea = false;
+  bool mDestroyCalled = false;
+  bool mOpeningAnimationSuppressed;
+  bool mAlwaysOnTop;
+  bool mIsEarlyBlankWindow = false;
+  bool mIsShowingPreXULSkeletonUI = false;
+  bool mResizable = false;
+  // Whether we're an alert window. Alert windows don't have taskbar icons and
+  // don't steal focus from other windows when opened. They're also expected to
+  // be of type WindowType::Dialog.
+  bool mIsAlert = false;
+  bool mIsPerformingDwmFlushHack = false;
+  bool mDraggingWindowWithMouse = false;
+  DWORD_PTR mOldStyle = 0;
+  DWORD_PTR mOldExStyle = 0;
+  nsNativeDragTarget* mNativeDragTarget = nullptr;
+  HKL mLastKeyboardLayout = 0;
+  mozilla::CheckInvariantWrapper<FrameState> mFrameState;
+  WindowHook mWindowHook;
+  uint32_t mPickerDisplayCount = 0;
+  HICON mIconSmall = nullptr;
+  HICON mIconBig = nullptr;
+  HWND mLastKillFocusWindow = nullptr;
+  PlatformCompositorWidgetDelegate* mCompositorWidgetDelegate = nullptr;
+
+  LayoutDeviceIntMargin NonClientSizeMargin() const {
+    return NonClientSizeMargin(mNonClientOffset);
+  }
+  LayoutDeviceIntMargin NonClientSizeMargin(
+      const LayoutDeviceIntMargin& aNonClientOffset) const;
+  LayoutDeviceIntMargin NormalWindowNonClientOffset() const;
+
+  // Non-client margin settings
+  // Pre-calculated outward offset applied to default frames
+  LayoutDeviceIntMargin mNonClientOffset;
+  // Margins set by the owner
+  LayoutDeviceIntMargin mNonClientMargins;
+  // Margins we'd like to set once chrome is reshown:
+  LayoutDeviceIntMargin mFutureMarginsOnceChromeShows;
+  // Indicates we need to apply margins once toggling chrome into showing:
+  bool mFutureMarginsToUse = false;
+
+  // Indicates custom frames are enabled
+  bool mCustomNonClient = false;
+  // Indicates custom resize margins are in effect
+  bool mUseResizeMarginOverrides = false;
+  // Width of the left and right portions of the resize region
+  mozilla::LayoutDeviceIntCoord mHorResizeMargin;
+  // Height of the top and bottom portions of the resize region
+  mozilla::LayoutDeviceIntCoord mVertResizeMargin;
+  // Height of the caption plus border
+  mozilla::LayoutDeviceIntCoord mCaptionHeight;
+
+  // not yet set, will be calculated on first use
+  double mDefaultScale = -1.0;
+
+  // not yet set, will be calculated on first use
+  float mAspectRatio = 0.0;
+
+  nsCOMPtr<nsIUserIdleServiceInternal> mIdleService;
+
+  // Draggable titlebar region maintained by UpdateWindowDraggingRegion
+  LayoutDeviceIntRegion mDraggableRegion;
+
+  // Graphics
+  LayoutDeviceIntRect mLastPaintBounds;
+
+  ResizeState mResizeState = NOT_RESIZING;
+
+  // Transparency
+  TransparencyMode mTransparencyMode = TransparencyMode::Opaque;
+  nsIntRegion mPossiblyTransparentRegion;
+
+  // Win7 Gesture processing and management
+  nsWinGesture mGesture;
+
+  // Weak ref to the nsITaskbarWindowPreview associated with this window
+  nsWeakPtr mTaskbarPreview = nullptr;
+
+  // The input region that determines whether mouse events should be ignored
+  // and pass through to the window below. This is currently only used for
+  // popups.
+  InputRegion mInputRegion;
+
+  // True if the taskbar (possibly through the tab preview) tells us that the
+  // icon has been created on the taskbar.
+  bool mHasTaskbarIconBeenCreated = false;
+
+  // Whether we're in the process of sending a WM_SETTEXT ourselves
+  bool mSendingSetText = false;
+
+  // Whether we were created as a child window (aka ChildWindow) or not.
+  bool mIsChildWindow : 1;
+
+  int32_t mCachedHitTestResult = 0;
+
+  // The point in time at which the last paint completed. We use this to avoid
+  //  painting too rapidly in response to frequent input events.
+  TimeStamp mLastPaintEndTime;
+
+  // Caching for hit test results (in client coordinates)
+  LayoutDeviceIntPoint mCachedHitTestPoint;
+  TimeStamp mCachedHitTestTime;
+
+  RefPtr<mozilla::widget::InProcessWinCompositorWidget> mBasicLayersSurface;
+
+  double mSizeConstraintsScale;  // scale in effect when setting constraints
+
+  // Will be calculated when layer manager is created.
+  int32_t mMaxTextureSize = -1;
+
+  // Pointer events processing and management
+  WinPointerEvents mPointerEvents;
+
+  ScreenPoint mLastPanGestureFocus;
+
+  // When true, used to indicate an async call to RequestFxrOutput to the GPU
+  // process after the Compositor is created
+  bool mRequestFxrOutputPending = false;
+
+  // A stack based class used in DispatchMouseEvent() to tell whether we should
+  // NOT open context menu when we receives WM_CONTEXTMENU after the
+  // DispatchMouseEvent calls.
+  // This class now works only in the case where a mouse up event happened in
+  // the overscroll gutter.
+  class MOZ_STACK_CLASS ContextMenuPreventer final {
+   public:
+    explicit ContextMenuPreventer(nsWindow* aWindow)
+        : mWindow(aWindow), mNeedsToPreventContextMenu(false){};
+    ~ContextMenuPreventer() {
+      mWindow->mNeedsToPreventContextMenu = mNeedsToPreventContextMenu;
+    }
+    void Update(const mozilla::WidgetMouseEvent& aEvent,
+                const nsIWidget::ContentAndAPZEventStatus& aEventStatus);
+
+   private:
+    nsWindow* mWindow;
+    bool mNeedsToPreventContextMenu = false;
+  };
+  friend class ContextMenuPreventer;
+  bool mNeedsToPreventContextMenu = false;
+
+  mozilla::UniquePtr<mozilla::widget::DirectManipulationOwner> mDmOwner;
+
+  // Client rect for minimize, maximize and close buttons.
+  mozilla::EnumeratedArray<WindowButtonType, WindowButtonType::Count,
+                           LayoutDeviceIntRect>
+      mWindowBtnRect;
+
+  mozilla::DataMutex<Desktop> mDesktopId;
+
+  // If set, indicates the edge of the NC region we should clear to black
+  // on next paint.  One of: ABE_TOP, ABE_BOTTOM, ABE_LEFT or ABE_RIGHT.
+  mozilla::Maybe<UINT> mClearNCEdge;
+
+  friend class nsWindowGfx;
+
+  static constexpr int kHiddenTaskbarSize = 2;
+};
+
+#endif  // WIDGET_WINDOWS_NSWINDOW_H_
diff --git a/widget/windows/nsWindowDbg.cpp b/widget/windows/nsWindowDbg.cpp
new file mode 100644
index 0000000000..8125a8532b
--- /dev/null
+++ b/widget/windows/nsWindowDbg.cpp
@@ -0,0 +1,1612 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * nsWindowDbg - Debug related utilities for nsWindow.
+ */
+
+#include "nsWindowDbg.h"
+#include "nsToolkit.h"
+#include "WinPointerEvents.h"
+#include "nsWindowLoggedMessages.h"
+#include "mozilla/Logging.h"
+#include "mozilla/Maybe.h"
+#include "nsWindow.h"
+#include "GeckoProfiler.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/dom/Document.h"
+
+#include <winuser.h>
+#include <dbt.h>
+#include <imm.h>
+#include <tpcshrd.h>
+
+#include <unordered_set>
+
+using namespace mozilla;
+using namespace mozilla::widget;
+extern mozilla::LazyLogModule gWindowsLog;
+static mozilla::LazyLogModule gWindowsEventLog("WindowsEvent");
+
+// currently defined in widget/windows/nsAppShell.cpp
+extern UINT sAppShellGeckoMsgId;
+
+#if defined(POPUP_ROLLUP_DEBUG_OUTPUT)
+MSGFEventMsgInfo gMSGFEvents[] = {
+    "MSGF_DIALOGBOX", 0,    "MSGF_MESSAGEBOX", 1, "MSGF_MENU", 2,
+    "MSGF_SCROLLBAR", 5,    "MSGF_NEXTWINDOW", 6, "MSGF_MAX",  8,
+    "MSGF_USER",      4096, nullptr,           0};
+#endif
+
+static long gEventCounter = 0;
+static UINT gLastEventMsg = 0;
+
+namespace geckoprofiler::markers {
+
+struct WindowProcMarker {
+  static constexpr Span<const char> MarkerTypeName() {
+    return MakeStringSpan("WindowProc");
+  }
+  static void StreamJSONMarkerData(baseprofiler::SpliceableJSONWriter& aWriter,
+                                   const ProfilerString8View& aMsgLoopName,
+                                   UINT aMsg, WPARAM aWParam, LPARAM aLParam) {
+    aWriter.StringProperty("messageLoop", aMsgLoopName);
+    aWriter.IntProperty("uMsg", aMsg);
+    const char* name;
+    if (aMsg < WM_USER) {
+      const auto eventMsgInfo = mozilla::widget::gAllEvents.find(aMsg);
+      if (eventMsgInfo != mozilla::widget::gAllEvents.end()) {
+        name = eventMsgInfo->second.mStr;
+      } else {
+        name = "ui message";
+      }
+    } else if (aMsg >= WM_USER && aMsg < WM_APP) {
+      name = "WM_USER message";
+    } else if (aMsg >= WM_APP && aMsg < 0xC000) {
+      name = "WM_APP message";
+    } else if (aMsg >= 0xC000 && aMsg < 0x10000) {
+      if (aMsg == sAppShellGeckoMsgId) {
+        name = "nsAppShell:EventID";
+      } else {
+        name = "registered Windows message";
+      }
+    } else {
+      name = "system message";
+    }
+    aWriter.StringProperty("name", MakeStringSpan(name));
+
+    if (aWParam) {
+      aWriter.IntProperty("wParam", aWParam);
+    }
+    if (aLParam) {
+      aWriter.IntProperty("lParam", aLParam);
+    }
+  }
+
+  static MarkerSchema MarkerTypeDisplay() {
+    using MS = MarkerSchema;
+    MS schema{MS::Location::MarkerChart, MS::Location::MarkerTable};
+    schema.AddKeyFormat("uMsg", MS::Format::Integer);
+    schema.SetChartLabel(
+        "{marker.data.messageLoop} | {marker.data.name} ({marker.data.uMsg})");
+    schema.SetTableLabel(
+        "{marker.name} - {marker.data.messageLoop} - {marker.data.name} "
+        "({marker.data.uMsg})");
+    schema.SetTooltipLabel(
+        "{marker.data.messageLoop} - {marker.name} - {marker.data.name}");
+    schema.AddKeyFormat("wParam", MS::Format::Integer);
+    schema.AddKeyFormat("lParam", MS::Format::Integer);
+    return schema;
+  }
+};
+
+}  // namespace geckoprofiler::markers
+
+namespace mozilla::widget {
+
+AutoProfilerMessageMarker::AutoProfilerMessageMarker(
+    Span<const char> aMsgLoopName, HWND hWnd, UINT msg, WPARAM wParam,
+    LPARAM lParam)
+    : mMsgLoopName(aMsgLoopName), mMsg(msg), mWParam(wParam), mLParam(lParam) {
+  if (profiler_thread_is_being_profiled_for_markers()) {
+    mOptions.emplace(MarkerOptions(MarkerTiming::IntervalStart()));
+    nsWindow* win = WinUtils::GetNSWindowPtr(hWnd);
+    if (win) {
+      nsIWidgetListener* wl = win->GetWidgetListener();
+      if (wl) {
+        PresShell* presShell = wl->GetPresShell();
+        if (presShell) {
+          dom::Document* doc = presShell->GetDocument();
+          if (doc) {
+            mOptions->Set(MarkerInnerWindowId(doc->InnerWindowID()));
+          }
+        }
+      }
+    }
+  }
+}
+
+AutoProfilerMessageMarker::~AutoProfilerMessageMarker() {
+  if (!profiler_thread_is_being_profiled_for_markers()) {
+    return;
+  }
+
+  if (mOptions) {
+    mOptions->TimingRef().SetIntervalEnd();
+  } else {
+    mOptions.emplace(MarkerOptions(MarkerTiming::IntervalEnd()));
+  }
+  profiler_add_marker(
+      "WindowProc", ::mozilla::baseprofiler::category::OTHER,
+      std::move(*mOptions), geckoprofiler::markers::WindowProcMarker{},
+      ProfilerString8View::WrapNullTerminatedString(mMsgLoopName.data()), mMsg,
+      mWParam, mLParam);
+}
+
+// Using an unordered_set so we can initialize this with nice syntax instead of
+// having to add them one at a time to a mozilla::HashSet.
+std::unordered_set<UINT> gEventsToLogOriginalParams = {
+    WM_WINDOWPOSCHANGING,  // (dummy comments for clang-format)
+    WM_SIZING,             //
+    WM_STYLECHANGING,
+    WM_GETTEXT,
+    WM_GETMINMAXINFO,
+    WM_MEASUREITEM,
+    WM_NCCALCSIZE,
+};
+
+// If you add an event here, you must add cases for these to
+// MakeMessageSpecificData() and AppendFriendlyMessageSpecificData()
+// in nsWindowLoggedMessages.cpp.
+std::unordered_set<UINT> gEventsToRecordInAboutPage = {
+    WM_WINDOWPOSCHANGING,  // (dummy comments for clang-format)
+    WM_WINDOWPOSCHANGED,   //
+    WM_SIZING,
+    WM_SIZE,
+    WM_DPICHANGED,
+    WM_SETTINGCHANGE,
+    WM_NCCALCSIZE,
+    WM_MOVE,
+    WM_MOVING,
+    WM_GETMINMAXINFO,
+};
+
+NativeEventLogger::NativeEventLogger(Span<const char> aMsgLoopName, HWND hwnd,
+                                     UINT msg, WPARAM wParam, LPARAM lParam)
+    : mProfilerMarker(aMsgLoopName, hwnd, msg, wParam, lParam),
+      mMsgLoopName(aMsgLoopName.data()),
+      mHwnd(hwnd),
+      mMsg(msg),
+      mWParam(wParam),
+      mLParam(lParam),
+      mResult(mozilla::Nothing()),
+      mShouldLogPostCall(false) {
+  if (NativeEventLoggerInternal()) {
+    // this event was logged, so reserve this counter number for the post-call
+    mEventCounter = mozilla::Some(gEventCounter);
+    ++gEventCounter;
+  }
+}
+
+NativeEventLogger::~NativeEventLogger() {
+  // If mResult is Nothing, perhaps an exception was thrown or something
+  // before SetResult() was supposed to be called.
+  if (mResult.isSome()) {
+    if (NativeEventLoggerInternal() && mEventCounter.isNothing()) {
+      // We didn't reserve a counter in the pre-call, so reserve it here.
+      ++gEventCounter;
+    }
+  }
+  if (mMsg == WM_DESTROY) {
+    // Remove any logged messages for this window.
+    WindowClosed(mHwnd);
+  }
+}
+
+void EventMsgInfo::LogParameters(nsCString& str, WPARAM wParam, LPARAM lParam,
+                                 bool isPreCall) {
+  if (mParamInfoFn) {
+    str = mParamInfoFn(wParam, lParam, isPreCall);
+  } else {
+    if (mWParamInfoFn) {
+      mWParamInfoFn(str, wParam, mWParamName, isPreCall);
+    }
+    if (mLParamInfoFn) {
+      if (mWParamInfoFn) {
+        str.AppendASCII(" ");
+      }
+      mLParamInfoFn(str, lParam, mLParamName, isPreCall);
+    }
+  }
+}
+
+nsAutoCString DefaultParamInfo(uint64_t wParam, uint64_t lParam,
+                               bool /* isPreCall */) {
+  nsAutoCString result;
+  result.AppendPrintf("wParam=0x%08llX lParam=0x%08llX", wParam, lParam);
+  return result;
+}
+
+void AppendEnumValueInfo(
+    nsCString& str, uint64_t value,
+    const std::unordered_map<uint64_t, const char*>& valuesAndNames,
+    const char* name) {
+  if (name != nullptr) {
+    str.AppendPrintf("%s=", name);
+  }
+  auto entry = valuesAndNames.find(value);
+  if (entry == valuesAndNames.end()) {
+    str.AppendPrintf("Unknown (0x%08llX)", value);
+  } else {
+    str.AppendASCII(entry->second);
+  }
+}
+
+bool AppendFlagsInfo(nsCString& str, uint64_t flags,
+                     const nsTArray<EnumValueAndName>& flagsAndNames,
+                     const char* name) {
+  if (name != nullptr) {
+    str.AppendPrintf("%s=", name);
+  }
+  bool firstAppend = true;
+  for (const EnumValueAndName& flagAndName : flagsAndNames) {
+    if (MOZ_UNLIKELY(flagAndName.mFlag == 0)) {
+      // Special case - only want to write this if nothing else was set.
+      // For this to make sense, 0 values should come at the end of
+      // flagsAndNames.
+      if (flags == 0 && firstAppend) {
+        firstAppend = false;
+        str.AppendASCII(flagAndName.mName);
+      }
+    } else if ((flags & flagAndName.mFlag) == flagAndName.mFlag) {
+      if (MOZ_LIKELY(!firstAppend)) {
+        str.Append('|');
+      }
+      firstAppend = false;
+      str.AppendASCII(flagAndName.mName);
+      flags = flags & ~flagAndName.mFlag;
+    }
+  }
+  if (flags != 0) {
+    if (MOZ_LIKELY(!firstAppend)) {
+      str.Append('|');
+    }
+    firstAppend = false;
+    str.AppendPrintf("Unknown (0x%08llX)", flags);
+  }
+  return !firstAppend;
+}
+
+// if mResult is not set, this is used to log the parameters passed in the
+// message, otherwise we are logging the parameters after we have handled the
+// message. This is useful for events where we might change the parameters while
+// handling the message (for example WM_GETTEXT and WM_NCCALCSIZE)
+// Returns whether this message was logged, so we need to reserve a
+// counter number for it.
+bool NativeEventLogger::NativeEventLoggerInternal() {
+  mozilla::LogLevel const targetLogLevel = [&] {
+    // These messages often take up more than 90% of logs if not filtered out.
+    if (mMsg == WM_SETCURSOR || mMsg == WM_MOUSEMOVE || mMsg == WM_NCHITTEST) {
+      return LogLevel::Verbose;
+    }
+    if (gLastEventMsg == mMsg) {
+      return LogLevel::Debug;
+    }
+    return LogLevel::Info;
+  }();
+
+  bool isPreCall = mResult.isNothing();
+  if (isPreCall || mShouldLogPostCall) {
+    bool recordInAboutPage = gEventsToRecordInAboutPage.find(mMsg) !=
+                             gEventsToRecordInAboutPage.end();
+    bool writeToWindowsLog;
+    if (isPreCall) {
+      writeToWindowsLog = MOZ_LOG_TEST(gWindowsEventLog, targetLogLevel);
+      bool shouldLogAtAll = recordInAboutPage || writeToWindowsLog;
+      // Since calling mParamInfoFn() allocates a string, only go down this code
+      // path if we're going to log this message to reduce allocations.
+      if (!shouldLogAtAll) {
+        return false;
+      }
+      mShouldLogPostCall = true;
+      bool shouldLogPreCall = gEventsToLogOriginalParams.find(mMsg) !=
+                              gEventsToLogOriginalParams.end();
+      if (!shouldLogPreCall) {
+        // Pre-call and we don't want to log both, so skip this one.
+        return false;
+      }
+    } else {
+      writeToWindowsLog = true;
+    }
+    if (recordInAboutPage) {
+      LogWindowMessage(mHwnd, mMsg, isPreCall,
+                       mEventCounter.valueOr(gEventCounter), mWParam, mLParam,
+                       mResult, mRetValue);
+    }
+    gLastEventMsg = mMsg;
+    if (writeToWindowsLog) {
+      const auto& eventMsgInfo = gAllEvents.find(mMsg);
+      const char* msgText = eventMsgInfo != gAllEvents.end()
+                                ? eventMsgInfo->second.mStr
+                                : nullptr;
+      nsAutoCString paramInfo;
+      if (eventMsgInfo != gAllEvents.end()) {
+        eventMsgInfo->second.LogParameters(paramInfo, mWParam, mLParam,
+                                           isPreCall);
+      } else {
+        paramInfo = DefaultParamInfo(mWParam, mLParam, isPreCall);
+      }
+      const char* resultMsg = mResult.isSome()
+                                  ? (mResult.value() ? "true" : "false")
+                                  : "initial call";
+      nsAutoCString logMessage;
+      logMessage.AppendPrintf(
+          "%s | %6ld %08" PRIX64 " - 0x%04X %s%s%s: 0x%08" PRIX64 " (%s)\n",
+          mMsgLoopName, mEventCounter.valueOr(gEventCounter),
+          reinterpret_cast<uint64_t>(mHwnd), mMsg,
+          msgText ? msgText : "Unknown", paramInfo.IsEmpty() ? "" : " ",
+          paramInfo.get(),
+          mResult.isSome() ? static_cast<uint64_t>(mRetValue) : 0, resultMsg);
+      const char* logMessageData = logMessage.Data();
+      MOZ_LOG(gWindowsEventLog, targetLogLevel, ("%s", logMessageData));
+    }
+    return true;
+  }
+  return false;
+}
+
+void TrueFalseParamInfo(nsCString& result, uint64_t value, const char* name,
+                        bool /* isPreCall */) {
+  result.AppendPrintf("%s=%s", name, value == TRUE ? "TRUE" : "FALSE");
+}
+
+void TrueFalseLowOrderWordParamInfo(nsCString& result, uint64_t value,
+                                    const char* name, bool /* isPreCall */) {
+  result.AppendPrintf("%s=%s", name, LOWORD(value) == TRUE ? "TRUE" : "FALSE");
+}
+
+void HexParamInfo(nsCString& result, uint64_t value, const char* name,
+                  bool /* isPreCall */) {
+  result.AppendPrintf("%s=0x%08llX", name, value);
+}
+
+void IntParamInfo(nsCString& result, uint64_t value, const char* name,
+                  bool /* isPreCall */) {
+  result.AppendPrintf("%s=%lld", name, value);
+}
+
+void RectParamInfo(nsCString& str, uint64_t value, const char* name,
+                   bool /* isPreCall */) {
+  LPRECT rect = reinterpret_cast<LPRECT>(value);
+  if (rect == nullptr) {
+    str.AppendPrintf("NULL rect?");
+    return;
+  }
+  if (name != nullptr) {
+    str.AppendPrintf("%s ", name);
+  }
+  str.AppendPrintf("left=%ld top=%ld right=%ld bottom=%ld", rect->left,
+                   rect->top, rect->right, rect->bottom);
+}
+
+#define VALANDNAME_ENTRY(_msg) \
+  { _msg, #_msg }
+
+void CreateStructParamInfo(nsCString& str, uint64_t value, const char* name,
+                           bool /* isPreCall */) {
+  CREATESTRUCT* createStruct = reinterpret_cast<CREATESTRUCT*>(value);
+  if (createStruct == nullptr) {
+    str.AppendASCII("NULL createStruct?");
+    return;
+  }
+  str.AppendPrintf(
+      "%s: hInstance=%p hMenu=%p hwndParent=%p lpszName=%S lpszClass=%S x=%d "
+      "y=%d cx=%d cy=%d",
+      name, createStruct->hInstance, createStruct->hMenu,
+      createStruct->hwndParent, createStruct->lpszName, createStruct->lpszClass,
+      createStruct->x, createStruct->y, createStruct->cx, createStruct->cy);
+  str.AppendASCII(" ");
+  const static nsTArray<EnumValueAndName> windowStyles = {
+      // these combinations of other flags need to come first
+      VALANDNAME_ENTRY(WS_OVERLAPPEDWINDOW), VALANDNAME_ENTRY(WS_POPUPWINDOW),
+      VALANDNAME_ENTRY(WS_CAPTION),
+      // regular flags
+      VALANDNAME_ENTRY(WS_POPUP), VALANDNAME_ENTRY(WS_CHILD),
+      VALANDNAME_ENTRY(WS_MINIMIZE), VALANDNAME_ENTRY(WS_VISIBLE),
+      VALANDNAME_ENTRY(WS_DISABLED), VALANDNAME_ENTRY(WS_CLIPSIBLINGS),
+      VALANDNAME_ENTRY(WS_CLIPCHILDREN), VALANDNAME_ENTRY(WS_MAXIMIZE),
+      VALANDNAME_ENTRY(WS_BORDER), VALANDNAME_ENTRY(WS_DLGFRAME),
+      VALANDNAME_ENTRY(WS_VSCROLL), VALANDNAME_ENTRY(WS_HSCROLL),
+      VALANDNAME_ENTRY(WS_SYSMENU), VALANDNAME_ENTRY(WS_THICKFRAME),
+      VALANDNAME_ENTRY(WS_GROUP), VALANDNAME_ENTRY(WS_TABSTOP),
+      // zero value needs to come last
+      VALANDNAME_ENTRY(WS_OVERLAPPED)};
+  AppendFlagsInfo(str, createStruct->style, windowStyles, "style");
+  str.AppendASCII(" ");
+  const nsTArray<EnumValueAndName> extendedWindowStyles = {
+      // these combinations of other flags need to come first
+      VALANDNAME_ENTRY(WS_EX_OVERLAPPEDWINDOW),
+      VALANDNAME_ENTRY(WS_EX_PALETTEWINDOW),
+      // regular flags
+      VALANDNAME_ENTRY(WS_EX_DLGMODALFRAME),
+      VALANDNAME_ENTRY(WS_EX_NOPARENTNOTIFY),
+      VALANDNAME_ENTRY(WS_EX_TOPMOST),
+      VALANDNAME_ENTRY(WS_EX_ACCEPTFILES),
+      VALANDNAME_ENTRY(WS_EX_TRANSPARENT),
+      VALANDNAME_ENTRY(WS_EX_MDICHILD),
+      VALANDNAME_ENTRY(WS_EX_TOOLWINDOW),
+      VALANDNAME_ENTRY(WS_EX_WINDOWEDGE),
+      VALANDNAME_ENTRY(WS_EX_CLIENTEDGE),
+      VALANDNAME_ENTRY(WS_EX_CONTEXTHELP),
+      VALANDNAME_ENTRY(WS_EX_RIGHT),
+      VALANDNAME_ENTRY(WS_EX_LEFT),
+      VALANDNAME_ENTRY(WS_EX_RTLREADING),
+      VALANDNAME_ENTRY(WS_EX_LTRREADING),
+      VALANDNAME_ENTRY(WS_EX_LEFTSCROLLBAR),
+      VALANDNAME_ENTRY(WS_EX_RIGHTSCROLLBAR),
+      VALANDNAME_ENTRY(WS_EX_CONTROLPARENT),
+      VALANDNAME_ENTRY(WS_EX_STATICEDGE),
+      VALANDNAME_ENTRY(WS_EX_APPWINDOW),
+      VALANDNAME_ENTRY(WS_EX_LAYERED),
+      VALANDNAME_ENTRY(WS_EX_NOINHERITLAYOUT),
+      VALANDNAME_ENTRY(WS_EX_LAYOUTRTL),
+      VALANDNAME_ENTRY(WS_EX_NOACTIVATE),
+      VALANDNAME_ENTRY(WS_EX_COMPOSITED),
+      VALANDNAME_ENTRY(WS_EX_NOREDIRECTIONBITMAP),
+  };
+  AppendFlagsInfo(str, createStruct->dwExStyle, extendedWindowStyles,
+                  "dwExStyle");
+}
+
+void XLowWordYHighWordParamInfo(nsCString& str, uint64_t value,
+                                const char* name, bool /* isPreCall */) {
+  str.AppendPrintf("%s: x=%d y=%d", name, static_cast<int>(LOWORD(value)),
+                   static_cast<int>(HIWORD(value)));
+}
+
+void PointParamInfo(nsCString& str, uint64_t value, const char* name,
+                    bool /* isPreCall */) {
+  str.AppendPrintf("%s: x=%d y=%d", name, static_cast<int>(GET_X_LPARAM(value)),
+                   static_cast<int>(GET_Y_LPARAM(value)));
+}
+
+void PointExplicitParamInfo(nsCString& str, POINT point, const char* name) {
+  str.AppendPrintf("%s: x=%ld y=%ld", name, point.x, point.y);
+}
+
+void PointsParamInfo(nsCString& str, uint64_t value, const char* name,
+                     bool /* isPreCall */) {
+  PPOINTS points = reinterpret_cast<PPOINTS>(&value);
+  str.AppendPrintf("%s: x=%d y=%d", name, points->x, points->y);
+}
+
+void VirtualKeyParamInfo(nsCString& result, uint64_t param, const char* name,
+                         bool /* isPreCall */) {
+  const static std::unordered_map<uint64_t, const char*> virtualKeys{
+      VALANDNAME_ENTRY(VK_LBUTTON),
+      VALANDNAME_ENTRY(VK_RBUTTON),
+      VALANDNAME_ENTRY(VK_CANCEL),
+      VALANDNAME_ENTRY(VK_MBUTTON),
+      VALANDNAME_ENTRY(VK_XBUTTON1),
+      VALANDNAME_ENTRY(VK_XBUTTON2),
+      VALANDNAME_ENTRY(VK_BACK),
+      VALANDNAME_ENTRY(VK_TAB),
+      VALANDNAME_ENTRY(VK_CLEAR),
+      VALANDNAME_ENTRY(VK_RETURN),
+      VALANDNAME_ENTRY(VK_SHIFT),
+      VALANDNAME_ENTRY(VK_CONTROL),
+      VALANDNAME_ENTRY(VK_MENU),
+      VALANDNAME_ENTRY(VK_PAUSE),
+      VALANDNAME_ENTRY(VK_CAPITAL),
+      VALANDNAME_ENTRY(VK_KANA),
+      VALANDNAME_ENTRY(VK_HANGUL),
+#ifdef VK_IME_ON
+      VALANDNAME_ENTRY(VK_IME_ON),
+#endif
+      VALANDNAME_ENTRY(VK_JUNJA),
+      VALANDNAME_ENTRY(VK_FINAL),
+      VALANDNAME_ENTRY(VK_HANJA),
+      VALANDNAME_ENTRY(VK_KANJI),
+#ifdef VK_IME_OFF
+      VALANDNAME_ENTRY(VK_IME_OFF),
+#endif
+      VALANDNAME_ENTRY(VK_ESCAPE),
+      VALANDNAME_ENTRY(VK_CONVERT),
+      VALANDNAME_ENTRY(VK_NONCONVERT),
+      VALANDNAME_ENTRY(VK_ACCEPT),
+      VALANDNAME_ENTRY(VK_MODECHANGE),
+      VALANDNAME_ENTRY(VK_SPACE),
+      VALANDNAME_ENTRY(VK_PRIOR),
+      VALANDNAME_ENTRY(VK_NEXT),
+      VALANDNAME_ENTRY(VK_END),
+      VALANDNAME_ENTRY(VK_HOME),
+      VALANDNAME_ENTRY(VK_LEFT),
+      VALANDNAME_ENTRY(VK_UP),
+      VALANDNAME_ENTRY(VK_RIGHT),
+      VALANDNAME_ENTRY(VK_DOWN),
+      VALANDNAME_ENTRY(VK_SELECT),
+      VALANDNAME_ENTRY(VK_PRINT),
+      VALANDNAME_ENTRY(VK_EXECUTE),
+      VALANDNAME_ENTRY(VK_SNAPSHOT),
+      VALANDNAME_ENTRY(VK_INSERT),
+      VALANDNAME_ENTRY(VK_DELETE),
+      VALANDNAME_ENTRY(VK_HELP),
+      VALANDNAME_ENTRY(VK_LWIN),
+      VALANDNAME_ENTRY(VK_RWIN),
+      VALANDNAME_ENTRY(VK_APPS),
+      VALANDNAME_ENTRY(VK_SLEEP),
+      VALANDNAME_ENTRY(VK_NUMPAD0),
+      VALANDNAME_ENTRY(VK_NUMPAD1),
+      VALANDNAME_ENTRY(VK_NUMPAD2),
+      VALANDNAME_ENTRY(VK_NUMPAD3),
+      VALANDNAME_ENTRY(VK_NUMPAD4),
+      VALANDNAME_ENTRY(VK_NUMPAD5),
+      VALANDNAME_ENTRY(VK_NUMPAD6),
+      VALANDNAME_ENTRY(VK_NUMPAD7),
+      VALANDNAME_ENTRY(VK_NUMPAD8),
+      VALANDNAME_ENTRY(VK_NUMPAD9),
+      VALANDNAME_ENTRY(VK_MULTIPLY),
+      VALANDNAME_ENTRY(VK_ADD),
+      VALANDNAME_ENTRY(VK_SEPARATOR),
+      VALANDNAME_ENTRY(VK_SUBTRACT),
+      VALANDNAME_ENTRY(VK_DECIMAL),
+      VALANDNAME_ENTRY(VK_DIVIDE),
+      VALANDNAME_ENTRY(VK_F1),
+      VALANDNAME_ENTRY(VK_F2),
+      VALANDNAME_ENTRY(VK_F3),
+      VALANDNAME_ENTRY(VK_F4),
+      VALANDNAME_ENTRY(VK_F5),
+      VALANDNAME_ENTRY(VK_F6),
+      VALANDNAME_ENTRY(VK_F7),
+      VALANDNAME_ENTRY(VK_F8),
+      VALANDNAME_ENTRY(VK_F9),
+      VALANDNAME_ENTRY(VK_F10),
+      VALANDNAME_ENTRY(VK_F11),
+      VALANDNAME_ENTRY(VK_F12),
+      VALANDNAME_ENTRY(VK_F13),
+      VALANDNAME_ENTRY(VK_F14),
+      VALANDNAME_ENTRY(VK_F15),
+      VALANDNAME_ENTRY(VK_F16),
+      VALANDNAME_ENTRY(VK_F17),
+      VALANDNAME_ENTRY(VK_F18),
+      VALANDNAME_ENTRY(VK_F19),
+      VALANDNAME_ENTRY(VK_F20),
+      VALANDNAME_ENTRY(VK_F21),
+      VALANDNAME_ENTRY(VK_F22),
+      VALANDNAME_ENTRY(VK_F23),
+      VALANDNAME_ENTRY(VK_F24),
+      VALANDNAME_ENTRY(VK_NUMLOCK),
+      VALANDNAME_ENTRY(VK_SCROLL),
+      VALANDNAME_ENTRY(VK_LSHIFT),
+      VALANDNAME_ENTRY(VK_RSHIFT),
+      VALANDNAME_ENTRY(VK_LCONTROL),
+      VALANDNAME_ENTRY(VK_RCONTROL),
+      VALANDNAME_ENTRY(VK_LMENU),
+      VALANDNAME_ENTRY(VK_RMENU),
+      VALANDNAME_ENTRY(VK_BROWSER_BACK),
+      VALANDNAME_ENTRY(VK_BROWSER_FORWARD),
+      VALANDNAME_ENTRY(VK_BROWSER_REFRESH),
+      VALANDNAME_ENTRY(VK_BROWSER_STOP),
+      VALANDNAME_ENTRY(VK_BROWSER_SEARCH),
+      VALANDNAME_ENTRY(VK_BROWSER_FAVORITES),
+      VALANDNAME_ENTRY(VK_BROWSER_HOME),
+      VALANDNAME_ENTRY(VK_VOLUME_MUTE),
+      VALANDNAME_ENTRY(VK_VOLUME_DOWN),
+      VALANDNAME_ENTRY(VK_VOLUME_UP),
+      VALANDNAME_ENTRY(VK_MEDIA_NEXT_TRACK),
+      VALANDNAME_ENTRY(VK_MEDIA_PREV_TRACK),
+      VALANDNAME_ENTRY(VK_MEDIA_STOP),
+      VALANDNAME_ENTRY(VK_MEDIA_PLAY_PAUSE),
+      VALANDNAME_ENTRY(VK_LAUNCH_MAIL),
+      VALANDNAME_ENTRY(VK_LAUNCH_MEDIA_SELECT),
+      VALANDNAME_ENTRY(VK_LAUNCH_APP1),
+      VALANDNAME_ENTRY(VK_LAUNCH_APP2),
+      VALANDNAME_ENTRY(VK_OEM_1),
+      VALANDNAME_ENTRY(VK_OEM_PLUS),
+      VALANDNAME_ENTRY(VK_OEM_COMMA),
+      VALANDNAME_ENTRY(VK_OEM_MINUS),
+      VALANDNAME_ENTRY(VK_OEM_PERIOD),
+      VALANDNAME_ENTRY(VK_OEM_2),
+      VALANDNAME_ENTRY(VK_OEM_3),
+      VALANDNAME_ENTRY(VK_OEM_4),
+      VALANDNAME_ENTRY(VK_OEM_5),
+      VALANDNAME_ENTRY(VK_OEM_6),
+      VALANDNAME_ENTRY(VK_OEM_7),
+      VALANDNAME_ENTRY(VK_OEM_8),
+      VALANDNAME_ENTRY(VK_OEM_102),
+      VALANDNAME_ENTRY(VK_PROCESSKEY),
+      VALANDNAME_ENTRY(VK_PACKET),
+      VALANDNAME_ENTRY(VK_ATTN),
+      VALANDNAME_ENTRY(VK_CRSEL),
+      VALANDNAME_ENTRY(VK_EXSEL),
+      VALANDNAME_ENTRY(VK_EREOF),
+      VALANDNAME_ENTRY(VK_PLAY),
+      VALANDNAME_ENTRY(VK_ZOOM),
+      VALANDNAME_ENTRY(VK_NONAME),
+      VALANDNAME_ENTRY(VK_PA1),
+      VALANDNAME_ENTRY(VK_OEM_CLEAR),
+      {0x30, "0"},
+      {0x31, "1"},
+      {0x32, "2"},
+      {0x33, "3"},
+      {0x34, "4"},
+      {0x35, "5"},
+      {0x36, "6"},
+      {0x37, "7"},
+      {0x38, "8"},
+      {0x39, "9"},
+      {0x41, "A"},
+      {0x42, "B"},
+      {0x43, "C"},
+      {0x44, "D"},
+      {0x45, "E"},
+      {0x46, "F"},
+      {0x47, "G"},
+      {0x48, "H"},
+      {0x49, "I"},
+      {0x4A, "J"},
+      {0x4B, "K"},
+      {0x4C, "L"},
+      {0x4D, "M"},
+      {0x4E, "N"},
+      {0x4F, "O"},
+      {0x50, "P"},
+      {0x51, "Q"},
+      {0x52, "S"},
+      {0x53, "T"},
+      {0x54, "U"},
+      {0x55, "V"},
+      {0x56, "W"},
+      {0x57, "X"},
+      {0x58, "Y"},
+      {0x59, "Z"},
+  };
+  AppendEnumValueInfo(result, param, virtualKeys, name);
+}
+
+void VirtualModifierKeysParamInfo(nsCString& result, uint64_t param,
+                                  const char* name, bool /* isPreCall */) {
+  const static nsTArray<EnumValueAndName> virtualKeys{
+      VALANDNAME_ENTRY(MK_CONTROL),  VALANDNAME_ENTRY(MK_LBUTTON),
+      VALANDNAME_ENTRY(MK_MBUTTON),  VALANDNAME_ENTRY(MK_RBUTTON),
+      VALANDNAME_ENTRY(MK_SHIFT),    VALANDNAME_ENTRY(MK_XBUTTON1),
+      VALANDNAME_ENTRY(MK_XBUTTON2), {0, "(none)"}};
+  AppendFlagsInfo(result, param, virtualKeys, name);
+}
+
+void ParentNotifyEventParamInfo(nsCString& str, uint64_t param,
+                                const char* /* name */, bool /* isPreCall */) {
+  const static std::unordered_map<uint64_t, const char*> eventValues{
+      VALANDNAME_ENTRY(WM_CREATE),      VALANDNAME_ENTRY(WM_DESTROY),
+      VALANDNAME_ENTRY(WM_LBUTTONDOWN), VALANDNAME_ENTRY(WM_MBUTTONDOWN),
+      VALANDNAME_ENTRY(WM_RBUTTONDOWN), VALANDNAME_ENTRY(WM_XBUTTONDOWN),
+      VALANDNAME_ENTRY(WM_POINTERDOWN)};
+  AppendEnumValueInfo(str, LOWORD(param), eventValues, "event");
+  str.AppendASCII(" ");
+  HexParamInfo(str, HIWORD(param), "hiWord", false);
+}
+
+void KeystrokeFlagsParamInfo(nsCString& str, uint64_t param,
+                             const char* /* name */, bool /* isPreCall */) {
+  WORD repeatCount = LOWORD(param);
+  WORD keyFlags = HIWORD(param);
+  WORD scanCode = LOBYTE(keyFlags);
+  bool isExtendedKey = (keyFlags & KF_EXTENDED) == KF_EXTENDED;
+  if (isExtendedKey) {
+    scanCode = MAKEWORD(scanCode, 0xE0);
+  }
+  bool contextCode = (keyFlags & KF_ALTDOWN) == KF_ALTDOWN;
+  bool wasKeyDown = (keyFlags & KF_REPEAT) == KF_REPEAT;
+  bool transitionState = (keyFlags & KF_UP) == KF_UP;
+
+  str.AppendPrintf(
+      "repeatCount: %d scanCode: %d isExtended: %d, contextCode: %d "
+      "previousKeyState: %d transitionState: %d",
+      repeatCount, scanCode, isExtendedKey ? 1 : 0, contextCode ? 1 : 0,
+      wasKeyDown ? 1 : 0, transitionState ? 1 : 0);
+};
+
+void VirtualKeysLowWordDistanceHighWordParamInfo(nsCString& str, uint64_t value,
+                                                 const char* /* name */,
+                                                 bool isPreCall) {
+  VirtualModifierKeysParamInfo(str, LOWORD(value), "virtualKeys", isPreCall);
+  str.AppendASCII(" ");
+  IntParamInfo(str, HIWORD(value), "distance", isPreCall);
+}
+
+void ShowWindowReasonParamInfo(nsCString& str, uint64_t value, const char* name,
+                               bool /* isPreCall */) {
+  const static std::unordered_map<uint64_t, const char*> showWindowReasonValues{
+      VALANDNAME_ENTRY(SW_OTHERUNZOOM),
+      VALANDNAME_ENTRY(SW_OTHERZOOM),
+      VALANDNAME_ENTRY(SW_PARENTCLOSING),
+      VALANDNAME_ENTRY(SW_PARENTOPENING),
+      {0, "Call to ShowWindow()"}};
+  AppendEnumValueInfo(str, value, showWindowReasonValues, name);
+}
+
+void WindowEdgeParamInfo(nsCString& str, uint64_t value, const char* name,
+                         bool /* isPreCall */) {
+  const static std::unordered_map<uint64_t, const char*> windowEdgeValues{
+      VALANDNAME_ENTRY(WMSZ_BOTTOM),      VALANDNAME_ENTRY(WMSZ_BOTTOMLEFT),
+      VALANDNAME_ENTRY(WMSZ_BOTTOMRIGHT), VALANDNAME_ENTRY(WMSZ_LEFT),
+      VALANDNAME_ENTRY(WMSZ_RIGHT),       VALANDNAME_ENTRY(WMSZ_TOP),
+      VALANDNAME_ENTRY(WMSZ_TOPLEFT),     VALANDNAME_ENTRY(WMSZ_TOPRIGHT)};
+  AppendEnumValueInfo(str, value, windowEdgeValues, name);
+}
+
+void UiActionParamInfo(nsCString& str, uint64_t value, const char* name,
+                       bool /* isPreCall */) {
+  const static std::unordered_map<uint64_t, const char*> uiActionValues{
+      VALANDNAME_ENTRY(SPI_GETACCESSTIMEOUT),
+      VALANDNAME_ENTRY(SPI_GETAUDIODESCRIPTION),
+      VALANDNAME_ENTRY(SPI_GETCLIENTAREAANIMATION),
+      VALANDNAME_ENTRY(SPI_GETDISABLEOVERLAPPEDCONTENT),
+      VALANDNAME_ENTRY(SPI_GETFILTERKEYS),
+      VALANDNAME_ENTRY(SPI_GETFOCUSBORDERHEIGHT),
+      VALANDNAME_ENTRY(SPI_GETFOCUSBORDERWIDTH),
+      VALANDNAME_ENTRY(SPI_GETHIGHCONTRAST),
+      VALANDNAME_ENTRY(SPI_GETLOGICALDPIOVERRIDE),
+      VALANDNAME_ENTRY(SPI_SETLOGICALDPIOVERRIDE),
+      VALANDNAME_ENTRY(SPI_GETMESSAGEDURATION),
+      VALANDNAME_ENTRY(SPI_GETMOUSECLICKLOCK),
+      VALANDNAME_ENTRY(SPI_GETMOUSECLICKLOCKTIME),
+      VALANDNAME_ENTRY(SPI_GETMOUSEKEYS),
+      VALANDNAME_ENTRY(SPI_GETMOUSESONAR),
+      VALANDNAME_ENTRY(SPI_GETMOUSEVANISH),
+      VALANDNAME_ENTRY(SPI_GETSCREENREADER),
+      VALANDNAME_ENTRY(SPI_GETSERIALKEYS),
+      VALANDNAME_ENTRY(SPI_GETSHOWSOUNDS),
+      VALANDNAME_ENTRY(SPI_GETSOUNDSENTRY),
+      VALANDNAME_ENTRY(SPI_GETSTICKYKEYS),
+      VALANDNAME_ENTRY(SPI_GETTOGGLEKEYS),
+      VALANDNAME_ENTRY(SPI_SETACCESSTIMEOUT),
+      VALANDNAME_ENTRY(SPI_SETAUDIODESCRIPTION),
+      VALANDNAME_ENTRY(SPI_SETCLIENTAREAANIMATION),
+      VALANDNAME_ENTRY(SPI_SETDISABLEOVERLAPPEDCONTENT),
+      VALANDNAME_ENTRY(SPI_SETFILTERKEYS),
+      VALANDNAME_ENTRY(SPI_SETFOCUSBORDERHEIGHT),
+      VALANDNAME_ENTRY(SPI_SETFOCUSBORDERWIDTH),
+      VALANDNAME_ENTRY(SPI_SETHIGHCONTRAST),
+      VALANDNAME_ENTRY(SPI_SETMESSAGEDURATION),
+      VALANDNAME_ENTRY(SPI_SETMOUSECLICKLOCK),
+      VALANDNAME_ENTRY(SPI_SETMOUSECLICKLOCKTIME),
+      VALANDNAME_ENTRY(SPI_SETMOUSEKEYS),
+      VALANDNAME_ENTRY(SPI_SETMOUSESONAR),
+      VALANDNAME_ENTRY(SPI_SETMOUSEVANISH),
+      VALANDNAME_ENTRY(SPI_SETSCREENREADER),
+      VALANDNAME_ENTRY(SPI_SETSERIALKEYS),
+      VALANDNAME_ENTRY(SPI_SETSHOWSOUNDS),
+      VALANDNAME_ENTRY(SPI_SETSOUNDSENTRY),
+      VALANDNAME_ENTRY(SPI_SETSTICKYKEYS),
+      VALANDNAME_ENTRY(SPI_SETTOGGLEKEYS),
+      VALANDNAME_ENTRY(SPI_GETCLEARTYPE),
+      VALANDNAME_ENTRY(SPI_GETDESKWALLPAPER),
+      VALANDNAME_ENTRY(SPI_GETDROPSHADOW),
+      VALANDNAME_ENTRY(SPI_GETFLATMENU),
+      VALANDNAME_ENTRY(SPI_GETFONTSMOOTHING),
+      VALANDNAME_ENTRY(SPI_GETFONTSMOOTHINGCONTRAST),
+      VALANDNAME_ENTRY(SPI_GETFONTSMOOTHINGORIENTATION),
+      VALANDNAME_ENTRY(SPI_GETFONTSMOOTHINGTYPE),
+      VALANDNAME_ENTRY(SPI_GETWORKAREA),
+      VALANDNAME_ENTRY(SPI_SETCLEARTYPE),
+      VALANDNAME_ENTRY(SPI_SETCURSORS),
+      VALANDNAME_ENTRY(SPI_SETDESKPATTERN),
+      VALANDNAME_ENTRY(SPI_SETDESKWALLPAPER),
+      VALANDNAME_ENTRY(SPI_SETDROPSHADOW),
+      VALANDNAME_ENTRY(SPI_SETFLATMENU),
+      VALANDNAME_ENTRY(SPI_SETFONTSMOOTHING),
+      VALANDNAME_ENTRY(SPI_SETFONTSMOOTHINGCONTRAST),
+      VALANDNAME_ENTRY(SPI_SETFONTSMOOTHINGORIENTATION),
+      VALANDNAME_ENTRY(SPI_SETFONTSMOOTHINGTYPE),
+      VALANDNAME_ENTRY(SPI_SETWORKAREA),
+      VALANDNAME_ENTRY(SPI_GETICONMETRICS),
+      VALANDNAME_ENTRY(SPI_GETICONTITLELOGFONT),
+      VALANDNAME_ENTRY(SPI_GETICONTITLEWRAP),
+      VALANDNAME_ENTRY(SPI_ICONHORIZONTALSPACING),
+      VALANDNAME_ENTRY(SPI_ICONVERTICALSPACING),
+      VALANDNAME_ENTRY(SPI_SETICONMETRICS),
+      VALANDNAME_ENTRY(SPI_SETICONS),
+      VALANDNAME_ENTRY(SPI_SETICONTITLELOGFONT),
+      VALANDNAME_ENTRY(SPI_SETICONTITLEWRAP),
+      VALANDNAME_ENTRY(SPI_GETBEEP),
+      VALANDNAME_ENTRY(SPI_GETBLOCKSENDINPUTRESETS),
+      VALANDNAME_ENTRY(SPI_GETCONTACTVISUALIZATION),
+      VALANDNAME_ENTRY(SPI_SETCONTACTVISUALIZATION),
+      VALANDNAME_ENTRY(SPI_GETDEFAULTINPUTLANG),
+      VALANDNAME_ENTRY(SPI_GETGESTUREVISUALIZATION),
+      VALANDNAME_ENTRY(SPI_SETGESTUREVISUALIZATION),
+      VALANDNAME_ENTRY(SPI_GETKEYBOARDCUES),
+      VALANDNAME_ENTRY(SPI_GETKEYBOARDDELAY),
+      VALANDNAME_ENTRY(SPI_GETKEYBOARDPREF),
+      VALANDNAME_ENTRY(SPI_GETKEYBOARDSPEED),
+      VALANDNAME_ENTRY(SPI_GETMOUSE),
+      VALANDNAME_ENTRY(SPI_GETMOUSEHOVERHEIGHT),
+      VALANDNAME_ENTRY(SPI_GETMOUSEHOVERTIME),
+      VALANDNAME_ENTRY(SPI_GETMOUSEHOVERWIDTH),
+      VALANDNAME_ENTRY(SPI_GETMOUSESPEED),
+      VALANDNAME_ENTRY(SPI_GETMOUSETRAILS),
+      VALANDNAME_ENTRY(SPI_GETMOUSEWHEELROUTING),
+      VALANDNAME_ENTRY(SPI_SETMOUSEWHEELROUTING),
+      VALANDNAME_ENTRY(SPI_GETPENVISUALIZATION),
+      VALANDNAME_ENTRY(SPI_SETPENVISUALIZATION),
+      VALANDNAME_ENTRY(SPI_GETSNAPTODEFBUTTON),
+      VALANDNAME_ENTRY(SPI_GETSYSTEMLANGUAGEBAR),
+      VALANDNAME_ENTRY(SPI_SETSYSTEMLANGUAGEBAR),
+      VALANDNAME_ENTRY(SPI_GETTHREADLOCALINPUTSETTINGS),
+      VALANDNAME_ENTRY(SPI_SETTHREADLOCALINPUTSETTINGS),
+      VALANDNAME_ENTRY(SPI_GETWHEELSCROLLCHARS),
+      VALANDNAME_ENTRY(SPI_GETWHEELSCROLLLINES),
+      VALANDNAME_ENTRY(SPI_SETBEEP),
+      VALANDNAME_ENTRY(SPI_SETBLOCKSENDINPUTRESETS),
+      VALANDNAME_ENTRY(SPI_SETDEFAULTINPUTLANG),
+      VALANDNAME_ENTRY(SPI_SETDOUBLECLICKTIME),
+      VALANDNAME_ENTRY(SPI_SETDOUBLECLKHEIGHT),
+      VALANDNAME_ENTRY(SPI_SETDOUBLECLKWIDTH),
+      VALANDNAME_ENTRY(SPI_SETKEYBOARDCUES),
+      VALANDNAME_ENTRY(SPI_SETKEYBOARDDELAY),
+      VALANDNAME_ENTRY(SPI_SETKEYBOARDPREF),
+      VALANDNAME_ENTRY(SPI_SETKEYBOARDSPEED),
+      VALANDNAME_ENTRY(SPI_SETLANGTOGGLE),
+      VALANDNAME_ENTRY(SPI_SETMOUSE),
+      VALANDNAME_ENTRY(SPI_SETMOUSEBUTTONSWAP),
+      VALANDNAME_ENTRY(SPI_SETMOUSEHOVERHEIGHT),
+      VALANDNAME_ENTRY(SPI_SETMOUSEHOVERTIME),
+      VALANDNAME_ENTRY(SPI_SETMOUSEHOVERWIDTH),
+      VALANDNAME_ENTRY(SPI_SETMOUSESPEED),
+      VALANDNAME_ENTRY(SPI_SETMOUSETRAILS),
+      VALANDNAME_ENTRY(SPI_SETSNAPTODEFBUTTON),
+      VALANDNAME_ENTRY(SPI_SETWHEELSCROLLCHARS),
+      VALANDNAME_ENTRY(SPI_SETWHEELSCROLLLINES),
+      VALANDNAME_ENTRY(SPI_GETMENUDROPALIGNMENT),
+      VALANDNAME_ENTRY(SPI_GETMENUFADE),
+      VALANDNAME_ENTRY(SPI_GETMENUSHOWDELAY),
+      VALANDNAME_ENTRY(SPI_SETMENUDROPALIGNMENT),
+      VALANDNAME_ENTRY(SPI_SETMENUFADE),
+      VALANDNAME_ENTRY(SPI_SETMENUSHOWDELAY),
+      VALANDNAME_ENTRY(SPI_GETLOWPOWERACTIVE),
+      VALANDNAME_ENTRY(SPI_GETLOWPOWERTIMEOUT),
+      VALANDNAME_ENTRY(SPI_GETPOWEROFFACTIVE),
+      VALANDNAME_ENTRY(SPI_GETPOWEROFFTIMEOUT),
+      VALANDNAME_ENTRY(SPI_SETLOWPOWERACTIVE),
+      VALANDNAME_ENTRY(SPI_SETLOWPOWERTIMEOUT),
+      VALANDNAME_ENTRY(SPI_SETPOWEROFFACTIVE),
+      VALANDNAME_ENTRY(SPI_SETPOWEROFFTIMEOUT),
+      VALANDNAME_ENTRY(SPI_GETSCREENSAVEACTIVE),
+      VALANDNAME_ENTRY(SPI_GETSCREENSAVERRUNNING),
+      VALANDNAME_ENTRY(SPI_GETSCREENSAVESECURE),
+      VALANDNAME_ENTRY(SPI_GETSCREENSAVETIMEOUT),
+      VALANDNAME_ENTRY(SPI_SETSCREENSAVEACTIVE),
+      VALANDNAME_ENTRY(SPI_SETSCREENSAVERRUNNING),
+      VALANDNAME_ENTRY(SPI_SETSCREENSAVESECURE),
+      VALANDNAME_ENTRY(SPI_SETSCREENSAVETIMEOUT),
+      VALANDNAME_ENTRY(SPI_GETHUNGAPPTIMEOUT),
+      VALANDNAME_ENTRY(SPI_GETWAITTOKILLTIMEOUT),
+      VALANDNAME_ENTRY(SPI_GETWAITTOKILLSERVICETIMEOUT),
+      VALANDNAME_ENTRY(SPI_SETHUNGAPPTIMEOUT),
+      VALANDNAME_ENTRY(SPI_SETWAITTOKILLTIMEOUT),
+      VALANDNAME_ENTRY(SPI_SETWAITTOKILLSERVICETIMEOUT),
+      VALANDNAME_ENTRY(SPI_GETCOMBOBOXANIMATION),
+      VALANDNAME_ENTRY(SPI_GETCURSORSHADOW),
+      VALANDNAME_ENTRY(SPI_GETGRADIENTCAPTIONS),
+      VALANDNAME_ENTRY(SPI_GETHOTTRACKING),
+      VALANDNAME_ENTRY(SPI_GETLISTBOXSMOOTHSCROLLING),
+      VALANDNAME_ENTRY(SPI_GETMENUANIMATION),
+      VALANDNAME_ENTRY(SPI_GETMENUUNDERLINES),
+      VALANDNAME_ENTRY(SPI_GETSELECTIONFADE),
+      VALANDNAME_ENTRY(SPI_GETTOOLTIPANIMATION),
+      VALANDNAME_ENTRY(SPI_GETTOOLTIPFADE),
+      VALANDNAME_ENTRY(SPI_GETUIEFFECTS),
+      VALANDNAME_ENTRY(SPI_SETCOMBOBOXANIMATION),
+      VALANDNAME_ENTRY(SPI_SETCURSORSHADOW),
+      VALANDNAME_ENTRY(SPI_SETGRADIENTCAPTIONS),
+      VALANDNAME_ENTRY(SPI_SETHOTTRACKING),
+      VALANDNAME_ENTRY(SPI_SETLISTBOXSMOOTHSCROLLING),
+      VALANDNAME_ENTRY(SPI_SETMENUANIMATION),
+      VALANDNAME_ENTRY(SPI_SETMENUUNDERLINES),
+      VALANDNAME_ENTRY(SPI_SETSELECTIONFADE),
+      VALANDNAME_ENTRY(SPI_SETTOOLTIPANIMATION),
+      VALANDNAME_ENTRY(SPI_SETTOOLTIPFADE),
+      VALANDNAME_ENTRY(SPI_SETUIEFFECTS),
+      VALANDNAME_ENTRY(SPI_GETACTIVEWINDOWTRACKING),
+      VALANDNAME_ENTRY(SPI_GETACTIVEWNDTRKZORDER),
+      VALANDNAME_ENTRY(SPI_GETACTIVEWNDTRKTIMEOUT),
+      VALANDNAME_ENTRY(SPI_GETANIMATION),
+      VALANDNAME_ENTRY(SPI_GETBORDER),
+      VALANDNAME_ENTRY(SPI_GETCARETWIDTH),
+      VALANDNAME_ENTRY(SPI_GETDOCKMOVING),
+      VALANDNAME_ENTRY(SPI_GETDRAGFROMMAXIMIZE),
+      VALANDNAME_ENTRY(SPI_GETDRAGFULLWINDOWS),
+      VALANDNAME_ENTRY(SPI_GETFOREGROUNDFLASHCOUNT),
+      VALANDNAME_ENTRY(SPI_GETFOREGROUNDLOCKTIMEOUT),
+      VALANDNAME_ENTRY(SPI_GETMINIMIZEDMETRICS),
+      VALANDNAME_ENTRY(SPI_GETMOUSEDOCKTHRESHOLD),
+      VALANDNAME_ENTRY(SPI_GETMOUSEDRAGOUTTHRESHOLD),
+      VALANDNAME_ENTRY(SPI_GETMOUSESIDEMOVETHRESHOLD),
+      VALANDNAME_ENTRY(SPI_GETNONCLIENTMETRICS),
+      VALANDNAME_ENTRY(SPI_GETPENDOCKTHRESHOLD),
+      VALANDNAME_ENTRY(SPI_GETPENDRAGOUTTHRESHOLD),
+      VALANDNAME_ENTRY(SPI_GETPENSIDEMOVETHRESHOLD),
+      VALANDNAME_ENTRY(SPI_GETSHOWIMEUI),
+      VALANDNAME_ENTRY(SPI_GETSNAPSIZING),
+      VALANDNAME_ENTRY(SPI_GETWINARRANGING),
+      VALANDNAME_ENTRY(SPI_SETACTIVEWINDOWTRACKING),
+      VALANDNAME_ENTRY(SPI_SETACTIVEWNDTRKZORDER),
+      VALANDNAME_ENTRY(SPI_SETACTIVEWNDTRKTIMEOUT),
+      VALANDNAME_ENTRY(SPI_SETANIMATION),
+      VALANDNAME_ENTRY(SPI_SETBORDER),
+      VALANDNAME_ENTRY(SPI_SETCARETWIDTH),
+      VALANDNAME_ENTRY(SPI_SETDOCKMOVING),
+      VALANDNAME_ENTRY(SPI_SETDRAGFROMMAXIMIZE),
+      VALANDNAME_ENTRY(SPI_SETDRAGFULLWINDOWS),
+      VALANDNAME_ENTRY(SPI_SETFOREGROUNDFLASHCOUNT),
+      VALANDNAME_ENTRY(SPI_SETFOREGROUNDLOCKTIMEOUT),
+      VALANDNAME_ENTRY(SPI_SETMINIMIZEDMETRICS),
+      VALANDNAME_ENTRY(SPI_SETMOUSEDOCKTHRESHOLD),
+      VALANDNAME_ENTRY(SPI_SETMOUSEDRAGOUTTHRESHOLD),
+      VALANDNAME_ENTRY(SPI_SETMOUSESIDEMOVETHRESHOLD),
+      VALANDNAME_ENTRY(SPI_SETNONCLIENTMETRICS),
+      VALANDNAME_ENTRY(SPI_SETPENDOCKTHRESHOLD),
+      VALANDNAME_ENTRY(SPI_SETPENDRAGOUTTHRESHOLD),
+      VALANDNAME_ENTRY(SPI_SETPENSIDEMOVETHRESHOLD),
+      VALANDNAME_ENTRY(SPI_SETSHOWIMEUI),
+      VALANDNAME_ENTRY(SPI_SETSNAPSIZING),
+      VALANDNAME_ENTRY(SPI_SETWINARRANGING),
+  };
+  AppendEnumValueInfo(str, value, uiActionValues, name);
+}
+
+nsAutoCString WmSizeParamInfo(uint64_t wParam, uint64_t lParam,
+                              bool /* isPreCall */) {
+  nsAutoCString result;
+  const static std::unordered_map<uint64_t, const char*> sizeValues{
+      VALANDNAME_ENTRY(SIZE_RESTORED), VALANDNAME_ENTRY(SIZE_MINIMIZED),
+      VALANDNAME_ENTRY(SIZE_MAXIMIZED), VALANDNAME_ENTRY(SIZE_MAXSHOW),
+      VALANDNAME_ENTRY(SIZE_MAXHIDE)};
+  AppendEnumValueInfo(result, wParam, sizeValues, "size");
+  result.AppendPrintf(" width=%d height=%d", static_cast<int>(LOWORD(lParam)),
+                      static_cast<int>(HIWORD(lParam)));
+  return result;
+}
+
+const nsTArray<EnumValueAndName> windowPositionFlags = {
+    VALANDNAME_ENTRY(SWP_DRAWFRAME),  VALANDNAME_ENTRY(SWP_HIDEWINDOW),
+    VALANDNAME_ENTRY(SWP_NOACTIVATE), VALANDNAME_ENTRY(SWP_NOCOPYBITS),
+    VALANDNAME_ENTRY(SWP_NOMOVE),     VALANDNAME_ENTRY(SWP_NOOWNERZORDER),
+    VALANDNAME_ENTRY(SWP_NOREDRAW),   VALANDNAME_ENTRY(SWP_NOSENDCHANGING),
+    VALANDNAME_ENTRY(SWP_NOSIZE),     VALANDNAME_ENTRY(SWP_NOZORDER),
+    VALANDNAME_ENTRY(SWP_SHOWWINDOW),
+};
+
+void WindowPosParamInfo(nsCString& str, uint64_t value, const char* name,
+                        bool /* isPreCall */) {
+  LPWINDOWPOS windowPos = reinterpret_cast<LPWINDOWPOS>(value);
+  if (windowPos == nullptr) {
+    str.AppendASCII("null windowPos?");
+    return;
+  }
+  HexParamInfo(str, reinterpret_cast<uint64_t>(windowPos->hwnd), "hwnd", false);
+  str.AppendASCII(" ");
+  HexParamInfo(str, reinterpret_cast<uint64_t>(windowPos->hwndInsertAfter),
+               "hwndInsertAfter", false);
+  str.AppendASCII(" ");
+  IntParamInfo(str, windowPos->x, "x", false);
+  str.AppendASCII(" ");
+  IntParamInfo(str, windowPos->y, "y", false);
+  str.AppendASCII(" ");
+  IntParamInfo(str, windowPos->cx, "cx", false);
+  str.AppendASCII(" ");
+  IntParamInfo(str, windowPos->cy, "cy", false);
+  str.AppendASCII(" ");
+  AppendFlagsInfo(str, windowPos->flags, windowPositionFlags, "flags");
+}
+
+void StyleOrExtendedParamInfo(nsCString& str, uint64_t value, const char* name,
+                              bool /* isPreCall */) {
+  const static std::unordered_map<uint64_t, const char*> styleOrExtended{
+      VALANDNAME_ENTRY(GWL_EXSTYLE), VALANDNAME_ENTRY(GWL_STYLE)};
+  AppendEnumValueInfo(str, value, styleOrExtended, name);
+}
+
+void StyleStructParamInfo(nsCString& str, uint64_t value, const char* name,
+                          bool /* isPreCall */) {
+  LPSTYLESTRUCT styleStruct = reinterpret_cast<LPSTYLESTRUCT>(value);
+  if (styleStruct == nullptr) {
+    str.AppendASCII("null STYLESTRUCT?");
+    return;
+  }
+  HexParamInfo(str, styleStruct->styleOld, "styleOld", false);
+  str.AppendASCII(" ");
+  HexParamInfo(str, styleStruct->styleNew, "styleNew", false);
+}
+
+void NcCalcSizeParamsParamInfo(nsCString& str, uint64_t value, const char* name,
+                               bool /* isPreCall */) {
+  LPNCCALCSIZE_PARAMS params = reinterpret_cast<LPNCCALCSIZE_PARAMS>(value);
+  if (params == nullptr) {
+    str.AppendASCII("null NCCALCSIZE_PARAMS?");
+    return;
+  }
+  str.AppendPrintf("%s[0]: ", name);
+  RectParamInfo(str, reinterpret_cast<uintptr_t>(&params->rgrc[0]), nullptr,
+                false);
+  str.AppendPrintf(" %s[1]: ", name);
+  RectParamInfo(str, reinterpret_cast<uintptr_t>(&params->rgrc[1]), nullptr,
+                false);
+  str.AppendPrintf(" %s[2]: ", name);
+  RectParamInfo(str, reinterpret_cast<uintptr_t>(&params->rgrc[2]), nullptr,
+                false);
+  str.AppendASCII(" ");
+  WindowPosParamInfo(str, reinterpret_cast<uintptr_t>(params->lppos), nullptr,
+                     false);
+}
+
+nsAutoCString WmNcCalcSizeParamInfo(uint64_t wParam, uint64_t lParam,
+                                    bool /* isPreCall */) {
+  nsAutoCString result;
+  TrueFalseParamInfo(result, wParam, "shouldIndicateValidArea", false);
+  result.AppendASCII(" ");
+  if (wParam == TRUE) {
+    NcCalcSizeParamsParamInfo(result, lParam, "ncCalcSizeParams", false);
+  } else {
+    RectParamInfo(result, lParam, "rect", false);
+  }
+  return result;
+}
+
+void ActivateWParamInfo(nsCString& result, uint64_t wParam, const char* name,
+                        bool /* isPreCall */) {
+  const static std::unordered_map<uint64_t, const char*> activateValues{
+      VALANDNAME_ENTRY(WA_ACTIVE), VALANDNAME_ENTRY(WA_CLICKACTIVE),
+      VALANDNAME_ENTRY(WA_INACTIVE)};
+  AppendEnumValueInfo(result, wParam, activateValues, name);
+}
+
+void HitTestParamInfo(nsCString& result, uint64_t param, const char* name,
+                      bool /* isPreCall */) {
+  const static std::unordered_map<uint64_t, const char*> hitTestResults{
+      VALANDNAME_ENTRY(HTBORDER),     VALANDNAME_ENTRY(HTBOTTOM),
+      VALANDNAME_ENTRY(HTBOTTOMLEFT), VALANDNAME_ENTRY(HTBOTTOMRIGHT),
+      VALANDNAME_ENTRY(HTCAPTION),    VALANDNAME_ENTRY(HTCLIENT),
+      VALANDNAME_ENTRY(HTCLOSE),      VALANDNAME_ENTRY(HTERROR),
+      VALANDNAME_ENTRY(HTGROWBOX),    VALANDNAME_ENTRY(HTHELP),
+      VALANDNAME_ENTRY(HTHSCROLL),    VALANDNAME_ENTRY(HTLEFT),
+      VALANDNAME_ENTRY(HTMENU),       VALANDNAME_ENTRY(HTMAXBUTTON),
+      VALANDNAME_ENTRY(HTMINBUTTON),  VALANDNAME_ENTRY(HTNOWHERE),
+      VALANDNAME_ENTRY(HTREDUCE),     VALANDNAME_ENTRY(HTRIGHT),
+      VALANDNAME_ENTRY(HTSIZE),       VALANDNAME_ENTRY(HTSYSMENU),
+      VALANDNAME_ENTRY(HTTOP),        VALANDNAME_ENTRY(HTTOPLEFT),
+      VALANDNAME_ENTRY(HTTOPRIGHT),   VALANDNAME_ENTRY(HTTRANSPARENT),
+      VALANDNAME_ENTRY(HTVSCROLL),    VALANDNAME_ENTRY(HTZOOM),
+  };
+  AppendEnumValueInfo(result, param, hitTestResults, name);
+}
+
+void SetCursorLParamInfo(nsCString& result, uint64_t lParam,
+                         const char* /* name */, bool /* isPreCall */) {
+  HitTestParamInfo(result, LOWORD(lParam), "hitTestResult", false);
+  result.AppendASCII(" ");
+  HexParamInfo(result, HIWORD(lParam), "message", false);
+}
+
+void MinMaxInfoParamInfo(nsCString& result, uint64_t value,
+                         const char* /* name */, bool /* isPreCall */) {
+  PMINMAXINFO minMaxInfo = reinterpret_cast<PMINMAXINFO>(value);
+  if (minMaxInfo == nullptr) {
+    result.AppendPrintf("NULL minMaxInfo?");
+    return;
+  }
+  PointExplicitParamInfo(result, minMaxInfo->ptMaxSize, "maxSize");
+  result.AppendASCII(" ");
+  PointExplicitParamInfo(result, minMaxInfo->ptMaxPosition, "maxPosition");
+  result.AppendASCII(" ");
+  PointExplicitParamInfo(result, minMaxInfo->ptMinTrackSize, "minTrackSize");
+  result.AppendASCII(" ");
+  PointExplicitParamInfo(result, minMaxInfo->ptMaxTrackSize, "maxTrackSize");
+}
+
+void WideStringParamInfo(nsCString& result, uint64_t value, const char* name,
+                         bool /* isPreCall */) {
+  result.AppendPrintf("%s=%S", name, reinterpret_cast<LPCWSTR>(value));
+}
+
+void DeviceEventParamInfo(nsCString& result, uint64_t value, const char* name,
+                          bool /* isPreCall */) {
+  const static std::unordered_map<uint64_t, const char*> deviceEventValues{
+      VALANDNAME_ENTRY(DBT_DEVNODES_CHANGED),
+      VALANDNAME_ENTRY(DBT_QUERYCHANGECONFIG),
+      VALANDNAME_ENTRY(DBT_CONFIGCHANGED),
+      VALANDNAME_ENTRY(DBT_CONFIGCHANGECANCELED),
+      VALANDNAME_ENTRY(DBT_DEVICEARRIVAL),
+      VALANDNAME_ENTRY(DBT_DEVICEQUERYREMOVE),
+      VALANDNAME_ENTRY(DBT_DEVICEQUERYREMOVEFAILED),
+      VALANDNAME_ENTRY(DBT_DEVICEREMOVEPENDING),
+      VALANDNAME_ENTRY(DBT_DEVICEREMOVECOMPLETE),
+      VALANDNAME_ENTRY(DBT_DEVICETYPESPECIFIC),
+      VALANDNAME_ENTRY(DBT_CUSTOMEVENT),
+      VALANDNAME_ENTRY(DBT_USERDEFINED)};
+  AppendEnumValueInfo(result, value, deviceEventValues, name);
+}
+
+void ResolutionParamInfo(nsCString& result, uint64_t value, const char* name,
+                         bool /* isPreCall */) {
+  result.AppendPrintf("horizontalRes=%d verticalRes=%d", LOWORD(value),
+                      HIWORD(value));
+}
+
+// Window message with default wParam/lParam logging
+#define ENTRY(_msg)                         \
+  {                                         \
+    _msg, { #_msg, _msg, DefaultParamInfo } \
+  }
+// Window message with no parameters
+#define ENTRY_WITH_NO_PARAM_INFO(_msg) \
+  {                                    \
+    _msg, { #_msg, _msg, nullptr }     \
+  }
+// Window message with custom parameter logging functions
+#define ENTRY_WITH_CUSTOM_PARAM_INFO(_msg, paramInfoFn) \
+  {                                                     \
+    _msg, { #_msg, _msg, paramInfoFn }                  \
+  }
+// Window message with separate custom wParam and lParam logging functions
+#define ENTRY_WITH_SPLIT_PARAM_INFOS(_msg, wParamInfoFn, wParamName,           \
+                                     lParamInfoFn, lParamName)                 \
+  {                                                                            \
+    _msg, {                                                                    \
+      #_msg, _msg, nullptr, wParamInfoFn, wParamName, lParamInfoFn, lParamName \
+    }                                                                          \
+  }
+std::unordered_map<UINT, EventMsgInfo> gAllEvents = {
+    ENTRY_WITH_NO_PARAM_INFO(WM_NULL),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_CREATE, nullptr, nullptr,
+                                 CreateStructParamInfo, "createStruct"),
+    ENTRY_WITH_NO_PARAM_INFO(WM_DESTROY),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_MOVE, nullptr, nullptr,
+                                 XLowWordYHighWordParamInfo, "upperLeft"),
+    ENTRY_WITH_CUSTOM_PARAM_INFO(WM_SIZE, WmSizeParamInfo),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_ACTIVATE, ActivateWParamInfo, "wParam",
+                                 HexParamInfo, "handle"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_SETFOCUS, HexParamInfo, "handle", nullptr,
+                                 nullptr),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_KILLFOCUS, HexParamInfo, "handle", nullptr,
+                                 nullptr),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_ENABLE, TrueFalseParamInfo, "enabled",
+                                 nullptr, nullptr),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_SETREDRAW, TrueFalseParamInfo,
+                                 "redrawState", nullptr, nullptr),
+    ENTRY(WM_SETTEXT),
+    ENTRY(WM_GETTEXT),
+    ENTRY(WM_GETTEXTLENGTH),
+    ENTRY_WITH_NO_PARAM_INFO(WM_PAINT),
+    ENTRY_WITH_NO_PARAM_INFO(WM_CLOSE),
+    ENTRY(WM_QUERYENDSESSION),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_QUIT, HexParamInfo, "exitCode", nullptr,
+                                 nullptr),
+    ENTRY(WM_QUERYOPEN),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_ERASEBKGND, HexParamInfo, "deviceContext",
+                                 nullptr, nullptr),
+    ENTRY(WM_SYSCOLORCHANGE),
+    ENTRY(WM_ENDSESSION),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_SHOWWINDOW, TrueFalseParamInfo,
+                                 "windowBeingShown", ShowWindowReasonParamInfo,
+                                 "status"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_SETTINGCHANGE, UiActionParamInfo,
+                                 "uiAction", WideStringParamInfo,
+                                 "paramChanged"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_DEVMODECHANGE, nullptr, nullptr,
+                                 WideStringParamInfo, "deviceName"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_ACTIVATEAPP, TrueFalseParamInfo,
+                                 "activated", HexParamInfo, "threadId"),
+    ENTRY(WM_FONTCHANGE),
+    ENTRY(WM_TIMECHANGE),
+    ENTRY(WM_CANCELMODE),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_SETCURSOR, HexParamInfo, "windowHandle",
+                                 SetCursorLParamInfo, ""),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_MOUSEACTIVATE, HexParamInfo, "windowHandle",
+                                 SetCursorLParamInfo, ""),
+    ENTRY(WM_CHILDACTIVATE),
+    ENTRY(WM_QUEUESYNC),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_GETMINMAXINFO, nullptr, nullptr,
+                                 MinMaxInfoParamInfo, ""),
+    ENTRY(WM_PAINTICON),
+    ENTRY(WM_ICONERASEBKGND),
+    ENTRY(WM_NEXTDLGCTL),
+    ENTRY(WM_SPOOLERSTATUS),
+    ENTRY(WM_DRAWITEM),
+    ENTRY(WM_MEASUREITEM),
+    ENTRY(WM_DELETEITEM),
+    ENTRY(WM_VKEYTOITEM),
+    ENTRY(WM_CHARTOITEM),
+    ENTRY(WM_SETFONT),
+    ENTRY(WM_GETFONT),
+    ENTRY(WM_SETHOTKEY),
+    ENTRY(WM_GETHOTKEY),
+    ENTRY(WM_QUERYDRAGICON),
+    ENTRY(WM_COMPAREITEM),
+    ENTRY(WM_GETOBJECT),
+    ENTRY(WM_COMPACTING),
+    ENTRY(WM_COMMNOTIFY),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_WINDOWPOSCHANGING, nullptr, nullptr,
+                                 WindowPosParamInfo, "newSizeAndPos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_WINDOWPOSCHANGED, nullptr, nullptr,
+                                 WindowPosParamInfo, "newSizeAndPos"),
+    ENTRY(WM_POWER),
+    ENTRY(WM_COPYDATA),
+    ENTRY(WM_CANCELJOURNAL),
+    ENTRY(WM_NOTIFY),
+    ENTRY(WM_INPUTLANGCHANGEREQUEST),
+    ENTRY(WM_INPUTLANGCHANGE),
+    ENTRY(WM_TCARD),
+    ENTRY(WM_HELP),
+    ENTRY(WM_USERCHANGED),
+    ENTRY(WM_NOTIFYFORMAT),
+    ENTRY(WM_CONTEXTMENU),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_STYLECHANGING, StyleOrExtendedParamInfo,
+                                 "styleOrExtended", StyleStructParamInfo,
+                                 "newStyles"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_STYLECHANGED, StyleOrExtendedParamInfo,
+                                 "styleOrExtended", StyleStructParamInfo,
+                                 "newStyles"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_DISPLAYCHANGE, IntParamInfo, "bitsPerPixel",
+                                 ResolutionParamInfo, ""),
+    ENTRY(WM_GETICON),
+    ENTRY(WM_SETICON),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCCREATE, nullptr, nullptr,
+                                 CreateStructParamInfo, "createStruct"),
+    ENTRY_WITH_NO_PARAM_INFO(WM_NCDESTROY),
+    ENTRY_WITH_CUSTOM_PARAM_INFO(WM_NCCALCSIZE, WmNcCalcSizeParamInfo),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCHITTEST, nullptr, nullptr,
+                                 XLowWordYHighWordParamInfo, "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCPAINT, HexParamInfo, "updateRegionHandle",
+                                 nullptr, nullptr),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCACTIVATE, TrueFalseParamInfo,
+                                 "isTitleBarOrIconActive", HexParamInfo,
+                                 "updateRegion"),
+    ENTRY(WM_GETDLGCODE),
+    ENTRY(WM_SYNCPAINT),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCMOUSEMOVE, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCLBUTTONDOWN, HitTestParamInfo,
+                                 "hitTestValue", PointsParamInfo, "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCLBUTTONUP, HitTestParamInfo,
+                                 "hitTestValue", PointsParamInfo, "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCLBUTTONDBLCLK, HitTestParamInfo,
+                                 "hitTestValue", PointsParamInfo, "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCRBUTTONDOWN, HitTestParamInfo,
+                                 "hitTestValue", PointsParamInfo, "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCRBUTTONUP, HitTestParamInfo,
+                                 "hitTestValue", PointsParamInfo, "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCRBUTTONDBLCLK, HitTestParamInfo,
+                                 "hitTestValue", PointsParamInfo, "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCMBUTTONDOWN, HitTestParamInfo,
+                                 "hitTestValue", PointsParamInfo, "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCMBUTTONUP, HitTestParamInfo,
+                                 "hitTestValue", PointsParamInfo, "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCMBUTTONDBLCLK, HitTestParamInfo,
+                                 "hitTestValue", PointsParamInfo, "mousePos"),
+    ENTRY(EM_GETSEL),
+    ENTRY(EM_SETSEL),
+    ENTRY(EM_GETRECT),
+    ENTRY(EM_SETRECT),
+    ENTRY(EM_SETRECTNP),
+    ENTRY(EM_SCROLL),
+    ENTRY(EM_LINESCROLL),
+    ENTRY(EM_SCROLLCARET),
+    ENTRY(EM_GETMODIFY),
+    ENTRY(EM_SETMODIFY),
+    ENTRY(EM_GETLINECOUNT),
+    ENTRY(EM_LINEINDEX),
+    ENTRY(EM_SETHANDLE),
+    ENTRY(EM_GETHANDLE),
+    ENTRY(EM_GETTHUMB),
+    ENTRY(EM_LINELENGTH),
+    ENTRY(EM_REPLACESEL),
+    ENTRY(EM_GETLINE),
+    ENTRY(EM_LIMITTEXT),
+    ENTRY(EM_CANUNDO),
+    ENTRY(EM_UNDO),
+    ENTRY(EM_FMTLINES),
+    ENTRY(EM_LINEFROMCHAR),
+    ENTRY(EM_SETTABSTOPS),
+    ENTRY(EM_SETPASSWORDCHAR),
+    ENTRY(EM_EMPTYUNDOBUFFER),
+    ENTRY(EM_GETFIRSTVISIBLELINE),
+    ENTRY(EM_SETREADONLY),
+    ENTRY(EM_SETWORDBREAKPROC),
+    ENTRY(EM_GETWORDBREAKPROC),
+    ENTRY(EM_GETPASSWORDCHAR),
+    ENTRY(EM_SETMARGINS),
+    ENTRY(EM_GETMARGINS),
+    ENTRY(EM_GETLIMITTEXT),
+    ENTRY(EM_POSFROMCHAR),
+    ENTRY(EM_CHARFROMPOS),
+    ENTRY(EM_SETIMESTATUS),
+    ENTRY(EM_GETIMESTATUS),
+    ENTRY(SBM_SETPOS),
+    ENTRY(SBM_GETPOS),
+    ENTRY(SBM_SETRANGE),
+    ENTRY(SBM_SETRANGEREDRAW),
+    ENTRY(SBM_GETRANGE),
+    ENTRY(SBM_ENABLE_ARROWS),
+    ENTRY(SBM_SETSCROLLINFO),
+    ENTRY(SBM_GETSCROLLINFO),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_KEYDOWN, VirtualKeyParamInfo, "vKey",
+                                 KeystrokeFlagsParamInfo, ""),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_KEYUP, VirtualKeyParamInfo, "vKey",
+                                 KeystrokeFlagsParamInfo, ""),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_CHAR, IntParamInfo, "charCode",
+                                 KeystrokeFlagsParamInfo, ""),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_DEADCHAR, IntParamInfo, "charCode",
+                                 KeystrokeFlagsParamInfo, ""),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_SYSKEYDOWN, VirtualKeyParamInfo, "vKey",
+                                 KeystrokeFlagsParamInfo, ""),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_SYSKEYUP, VirtualKeyParamInfo, "vKey",
+                                 KeystrokeFlagsParamInfo, ""),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_SYSCHAR, IntParamInfo, "charCode",
+                                 KeystrokeFlagsParamInfo, ""),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_SYSDEADCHAR, IntParamInfo, "charCode",
+                                 KeystrokeFlagsParamInfo, ""),
+    ENTRY(WM_KEYLAST),
+    ENTRY(WM_IME_STARTCOMPOSITION),
+    ENTRY(WM_IME_ENDCOMPOSITION),
+    ENTRY(WM_IME_COMPOSITION),
+    ENTRY(WM_INITDIALOG),
+    ENTRY(WM_COMMAND),
+    ENTRY(WM_SYSCOMMAND),
+    ENTRY(WM_TIMER),
+    ENTRY(WM_HSCROLL),
+    ENTRY(WM_VSCROLL),
+    ENTRY(WM_INITMENU),
+    ENTRY(WM_INITMENUPOPUP),
+    ENTRY(WM_MENUSELECT),
+    ENTRY(WM_MENUCHAR),
+    ENTRY(WM_ENTERIDLE),
+    ENTRY(WM_MENURBUTTONUP),
+    ENTRY(WM_MENUDRAG),
+    ENTRY(WM_MENUGETOBJECT),
+    ENTRY(WM_UNINITMENUPOPUP),
+    ENTRY(WM_MENUCOMMAND),
+    ENTRY(WM_CHANGEUISTATE),
+    ENTRY(WM_QUERYUISTATE),
+    ENTRY(WM_UPDATEUISTATE),
+    ENTRY(WM_CTLCOLORMSGBOX),
+    ENTRY(WM_CTLCOLOREDIT),
+    ENTRY(WM_CTLCOLORLISTBOX),
+    ENTRY(WM_CTLCOLORBTN),
+    ENTRY(WM_CTLCOLORDLG),
+    ENTRY(WM_CTLCOLORSCROLLBAR),
+    ENTRY(WM_CTLCOLORSTATIC),
+    ENTRY(CB_GETEDITSEL),
+    ENTRY(CB_LIMITTEXT),
+    ENTRY(CB_SETEDITSEL),
+    ENTRY(CB_ADDSTRING),
+    ENTRY(CB_DELETESTRING),
+    ENTRY(CB_DIR),
+    ENTRY(CB_GETCOUNT),
+    ENTRY(CB_GETCURSEL),
+    ENTRY(CB_GETLBTEXT),
+    ENTRY(CB_GETLBTEXTLEN),
+    ENTRY(CB_INSERTSTRING),
+    ENTRY(CB_RESETCONTENT),
+    ENTRY(CB_FINDSTRING),
+    ENTRY(CB_SELECTSTRING),
+    ENTRY(CB_SETCURSEL),
+    ENTRY(CB_SHOWDROPDOWN),
+    ENTRY(CB_GETITEMDATA),
+    ENTRY(CB_SETITEMDATA),
+    ENTRY(CB_GETDROPPEDCONTROLRECT),
+    ENTRY(CB_SETITEMHEIGHT),
+    ENTRY(CB_GETITEMHEIGHT),
+    ENTRY(CB_SETEXTENDEDUI),
+    ENTRY(CB_GETEXTENDEDUI),
+    ENTRY(CB_GETDROPPEDSTATE),
+    ENTRY(CB_FINDSTRINGEXACT),
+    ENTRY(CB_SETLOCALE),
+    ENTRY(CB_GETLOCALE),
+    ENTRY(CB_GETTOPINDEX),
+    ENTRY(CB_SETTOPINDEX),
+    ENTRY(CB_GETHORIZONTALEXTENT),
+    ENTRY(CB_SETHORIZONTALEXTENT),
+    ENTRY(CB_GETDROPPEDWIDTH),
+    ENTRY(CB_SETDROPPEDWIDTH),
+    ENTRY(CB_INITSTORAGE),
+    ENTRY(CB_MSGMAX),
+    ENTRY(LB_ADDSTRING),
+    ENTRY(LB_INSERTSTRING),
+    ENTRY(LB_DELETESTRING),
+    ENTRY(LB_SELITEMRANGEEX),
+    ENTRY(LB_RESETCONTENT),
+    ENTRY(LB_SETSEL),
+    ENTRY(LB_SETCURSEL),
+    ENTRY(LB_GETSEL),
+    ENTRY(LB_GETCURSEL),
+    ENTRY(LB_GETTEXT),
+    ENTRY(LB_GETTEXTLEN),
+    ENTRY(LB_GETCOUNT),
+    ENTRY(LB_SELECTSTRING),
+    ENTRY(LB_DIR),
+    ENTRY(LB_GETTOPINDEX),
+    ENTRY(LB_FINDSTRING),
+    ENTRY(LB_GETSELCOUNT),
+    ENTRY(LB_GETSELITEMS),
+    ENTRY(LB_SETTABSTOPS),
+    ENTRY(LB_GETHORIZONTALEXTENT),
+    ENTRY(LB_SETHORIZONTALEXTENT),
+    ENTRY(LB_SETCOLUMNWIDTH),
+    ENTRY(LB_ADDFILE),
+    ENTRY(LB_SETTOPINDEX),
+    ENTRY(LB_GETITEMRECT),
+    ENTRY(LB_GETITEMDATA),
+    ENTRY(LB_SETITEMDATA),
+    ENTRY(LB_SELITEMRANGE),
+    ENTRY(LB_SETANCHORINDEX),
+    ENTRY(LB_GETANCHORINDEX),
+    ENTRY(LB_SETCARETINDEX),
+    ENTRY(LB_GETCARETINDEX),
+    ENTRY(LB_SETITEMHEIGHT),
+    ENTRY(LB_GETITEMHEIGHT),
+    ENTRY(LB_FINDSTRINGEXACT),
+    ENTRY(LB_SETLOCALE),
+    ENTRY(LB_GETLOCALE),
+    ENTRY(LB_SETCOUNT),
+    ENTRY(LB_INITSTORAGE),
+    ENTRY(LB_ITEMFROMPOINT),
+    ENTRY(LB_MSGMAX),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_MOUSEMOVE, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_LBUTTONDOWN, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_LBUTTONUP, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_LBUTTONDBLCLK, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_RBUTTONDOWN, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_RBUTTONUP, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_RBUTTONDBLCLK, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_MBUTTONDOWN, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_MBUTTONUP, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_MBUTTONDBLCLK, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_MOUSEWHEEL,
+                                 VirtualKeysLowWordDistanceHighWordParamInfo,
+                                 "", XLowWordYHighWordParamInfo, "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_MOUSEHWHEEL,
+                                 VirtualKeysLowWordDistanceHighWordParamInfo,
+                                 "", XLowWordYHighWordParamInfo, "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_PARENTNOTIFY, ParentNotifyEventParamInfo,
+                                 "", PointParamInfo, "pointerLocation"),
+    ENTRY(WM_ENTERMENULOOP),
+    ENTRY(WM_EXITMENULOOP),
+    ENTRY(WM_NEXTMENU),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_SIZING, WindowEdgeParamInfo, "edge",
+                                 RectParamInfo, "rect"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_CAPTURECHANGED, nullptr, nullptr,
+                                 HexParamInfo, "windowHandle"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_MOVING, nullptr, nullptr, RectParamInfo,
+                                 "rect"),
+    ENTRY(WM_POWERBROADCAST),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_DEVICECHANGE, DeviceEventParamInfo, "event",
+                                 HexParamInfo, "data"),
+    ENTRY(WM_MDICREATE),
+    ENTRY(WM_MDIDESTROY),
+    ENTRY(WM_MDIACTIVATE),
+    ENTRY(WM_MDIRESTORE),
+    ENTRY(WM_MDINEXT),
+    ENTRY(WM_MDIMAXIMIZE),
+    ENTRY(WM_MDITILE),
+    ENTRY(WM_MDICASCADE),
+    ENTRY(WM_MDIICONARRANGE),
+    ENTRY(WM_MDIGETACTIVE),
+    ENTRY(WM_MDISETMENU),
+    ENTRY(WM_ENTERSIZEMOVE),
+    ENTRY(WM_EXITSIZEMOVE),
+    ENTRY(WM_DROPFILES),
+    ENTRY(WM_MDIREFRESHMENU),
+    ENTRY(WM_IME_SETCONTEXT),
+    ENTRY(WM_IME_NOTIFY),
+    ENTRY(WM_IME_CONTROL),
+    ENTRY(WM_IME_COMPOSITIONFULL),
+    ENTRY(WM_IME_SELECT),
+    ENTRY(WM_IME_CHAR),
+    ENTRY(WM_IME_REQUEST),
+    ENTRY(WM_IME_KEYDOWN),
+    ENTRY(WM_IME_KEYUP),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_NCMOUSEHOVER, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_MOUSEHOVER, VirtualModifierKeysParamInfo,
+                                 "virtualKeys", XLowWordYHighWordParamInfo,
+                                 "mousePos"),
+    ENTRY_WITH_NO_PARAM_INFO(WM_NCMOUSELEAVE),
+    ENTRY_WITH_NO_PARAM_INFO(WM_MOUSELEAVE),
+    ENTRY(WM_CUT),
+    ENTRY(WM_COPY),
+    ENTRY(WM_PASTE),
+    ENTRY(WM_CLEAR),
+    ENTRY(WM_UNDO),
+    ENTRY(WM_RENDERFORMAT),
+    ENTRY(WM_RENDERALLFORMATS),
+    ENTRY(WM_DESTROYCLIPBOARD),
+    ENTRY(WM_DRAWCLIPBOARD),
+    ENTRY(WM_PAINTCLIPBOARD),
+    ENTRY(WM_VSCROLLCLIPBOARD),
+    ENTRY(WM_SIZECLIPBOARD),
+    ENTRY(WM_ASKCBFORMATNAME),
+    ENTRY(WM_CHANGECBCHAIN),
+    ENTRY(WM_HSCROLLCLIPBOARD),
+    ENTRY(WM_QUERYNEWPALETTE),
+    ENTRY(WM_PALETTEISCHANGING),
+    ENTRY(WM_PALETTECHANGED),
+    ENTRY(WM_HOTKEY),
+    ENTRY(WM_PRINT),
+    ENTRY(WM_PRINTCLIENT),
+    ENTRY(WM_THEMECHANGED),
+    ENTRY(WM_HANDHELDFIRST),
+    ENTRY(WM_HANDHELDLAST),
+    ENTRY(WM_AFXFIRST),
+    ENTRY(WM_AFXLAST),
+    ENTRY(WM_PENWINFIRST),
+    ENTRY(WM_PENWINLAST),
+    ENTRY(WM_APP),
+    ENTRY_WITH_NO_PARAM_INFO(WM_DWMCOMPOSITIONCHANGED),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_DWMNCRENDERINGCHANGED, TrueFalseParamInfo,
+                                 "DwmNcRendering", nullptr, nullptr),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_DWMCOLORIZATIONCOLORCHANGED, HexParamInfo,
+                                 "color:AARRGGBB", TrueFalseParamInfo,
+                                 "isOpaque"),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_DWMWINDOWMAXIMIZEDCHANGE,
+                                 TrueFalseParamInfo, "maximized", nullptr,
+                                 nullptr),
+    ENTRY(WM_DWMSENDICONICTHUMBNAIL),  // lParam: HIWORD is x, LOWORD is y
+    ENTRY_WITH_NO_PARAM_INFO(WM_DWMSENDICONICLIVEPREVIEWBITMAP),
+    ENTRY(WM_TABLET_QUERYSYSTEMGESTURESTATUS),
+    ENTRY(WM_GESTURE),
+    ENTRY(WM_GESTURENOTIFY),
+    ENTRY(WM_GETTITLEBARINFOEX),
+    ENTRY_WITH_SPLIT_PARAM_INFOS(WM_DPICHANGED, XLowWordYHighWordParamInfo,
+                                 "newDPI", RectParamInfo,
+                                 "suggestedSizeAndPos"),
+};
+#undef ENTRY
+#undef ENTRY_WITH_NO_PARAM_INFO
+#undef ENTRY_WITH_CUSTOM_PARAM_INFO
+#undef ENTRY_WITH_SPLIT_PARAM_INFO
+
+}  // namespace mozilla::widget
+
+#ifdef DEBUG
+void DDError(const char* msg, HRESULT hr) {
+  /*XXX make nicer */
+  MOZ_LOG(gWindowsLog, LogLevel::Error,
+          ("DirectDraw error %s: 0x%08lx\n", msg, hr));
+}
+#endif
+
+#ifdef DEBUG_VK
+bool is_vk_down(int vk) {
+  SHORT st = GetKeyState(vk);
+#  ifdef DEBUG
+  MOZ_LOG(gWindowsLog, LogLevel::Info, ("is_vk_down vk=%x st=%x\n", vk, st));
+#  endif
+  return (st < 0);
+}
+#endif
diff --git a/widget/windows/nsWindowDbg.h b/widget/windows/nsWindowDbg.h
new file mode 100644
index 0000000000..c739966fd5
--- /dev/null
+++ b/widget/windows/nsWindowDbg.h
@@ -0,0 +1,153 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WindowDbg_h__
+#define WindowDbg_h__
+
+/*
+ * nsWindowDbg - Debug related utilities for nsWindow.
+ */
+
+#include "nsWindowDefs.h"
+#include "mozilla/BaseProfilerMarkersPrerequisites.h"
+
+// Enables debug output for popup rollup hooks
+// #define POPUP_ROLLUP_DEBUG_OUTPUT
+
+// Enable window size and state debug output
+// #define WINSTATE_DEBUG_OUTPUT
+
+// nsIWidget defines a set of debug output statements
+// that are called in various places within the code.
+// #define WIDGET_DEBUG_OUTPUT
+
+// Enable IS_VK_DOWN debug output
+// #define DEBUG_VK
+
+namespace mozilla::widget {
+
+class MOZ_RAII AutoProfilerMessageMarker {
+ public:
+  explicit AutoProfilerMessageMarker(Span<const char> aMsgLoopName, HWND hWnd,
+                                     UINT msg, WPARAM wParam, LPARAM lParam);
+
+  ~AutoProfilerMessageMarker();
+
+ protected:
+  Maybe<MarkerOptions> mOptions;
+  Span<const char> mMsgLoopName;
+  UINT mMsg;
+  WPARAM mWParam;
+  LPARAM mLParam;
+};
+
+// Windows message debugging data
+struct EventMsgInfo {
+  const char* mStr;
+  UINT mId;
+  std::function<nsAutoCString(WPARAM, LPARAM, bool)> mParamInfoFn;
+  std::function<void(nsCString&, WPARAM, const char*, bool)> mWParamInfoFn;
+  const char* mWParamName;
+  std::function<void(nsCString&, LPARAM, const char*, bool)> mLParamInfoFn;
+  const char* mLParamName;
+  void LogParameters(nsCString& str, WPARAM wParam, LPARAM lParam,
+                     bool isPreCall);
+};
+extern std::unordered_map<UINT, EventMsgInfo> gAllEvents;
+
+// RAII-style class to log before and after an event is handled.
+class NativeEventLogger final {
+ public:
+  template <size_t N>
+  NativeEventLogger(const char (&aMsgLoopName)[N], HWND hwnd, UINT msg,
+                    WPARAM wParam, LPARAM lParam)
+      : NativeEventLogger(Span(aMsgLoopName), hwnd, msg, wParam, lParam) {}
+
+  void SetResult(LRESULT lresult, bool result) {
+    mRetValue = lresult;
+    mResult = mozilla::Some(result);
+  }
+  ~NativeEventLogger();
+
+ private:
+  NativeEventLogger(Span<const char> aMsgLoopName, HWND hwnd, UINT msg,
+                    WPARAM wParam, LPARAM lParam);
+  bool NativeEventLoggerInternal();
+
+  AutoProfilerMessageMarker mProfilerMarker;
+  const char* mMsgLoopName;
+  const HWND mHwnd;
+  const UINT mMsg;
+  const WPARAM mWParam;
+  const LPARAM mLParam;
+  mozilla::Maybe<long> mEventCounter;
+  // not const because these will be set after the event is handled
+  mozilla::Maybe<bool> mResult;
+  LRESULT mRetValue = 0;
+
+  bool mShouldLogPostCall;
+};
+
+struct EnumValueAndName {
+  uint64_t mFlag;
+  const char* mName;
+};
+
+// Appends to str a description of the flags passed in.
+// flagsAndNames is a list of flag values with a string description
+// for each one. These are processed in order, so if there are
+// flag values that are combination of individual values (for example
+// something like WS_OVERLAPPEDWINDOW) they need to come first
+// in the flagsAndNames array.
+// A 0 flag value will only be written if the flags input is exactly
+// 0, and it must come last in the flagsAndNames array.
+// Returns whether any info was appended to str.
+bool AppendFlagsInfo(nsCString& str, uint64_t flags,
+                     const nsTArray<EnumValueAndName>& flagsAndNames,
+                     const char* name);
+
+nsAutoCString WmSizeParamInfo(uint64_t wParam, uint64_t lParam, bool isPreCall);
+void XLowWordYHighWordParamInfo(nsCString& str, uint64_t value,
+                                const char* name, bool isPreCall);
+void WindowPosParamInfo(nsCString& str, uint64_t value, const char* name,
+                        bool isPreCall);
+void WindowEdgeParamInfo(nsCString& str, uint64_t value, const char* name,
+                         bool isPreCall);
+void RectParamInfo(nsCString& str, uint64_t value, const char* name,
+                   bool isPreCall);
+void UiActionParamInfo(nsCString& str, uint64_t value, const char* name,
+                       bool isPreCall);
+void WideStringParamInfo(nsCString& result, uint64_t value, const char* name,
+                         bool isPreCall);
+void MinMaxInfoParamInfo(nsCString& result, uint64_t value, const char* name,
+                         bool isPreCall);
+nsAutoCString WmNcCalcSizeParamInfo(uint64_t wParam, uint64_t lParam,
+                                    bool isPreCall);
+}  // namespace mozilla::widget
+
+#if defined(POPUP_ROLLUP_DEBUG_OUTPUT)
+typedef struct {
+  char* mStr;
+  int mId;
+} MSGFEventMsgInfo;
+
+#  define DISPLAY_NMM_PRT(_arg) \
+    MOZ_LOG(gWindowsLog, mozilla::LogLevel::Info, ((_arg)));
+#else
+#  define DISPLAY_NMM_PRT(_arg)
+#endif  // defined(POPUP_ROLLUP_DEBUG_OUTPUT)
+
+#if defined(DEBUG)
+void DDError(const char* msg, HRESULT hr);
+#endif  // defined(DEBUG)
+
+#if defined(DEBUG_VK)
+bool is_vk_down(int vk);
+#  define IS_VK_DOWN is_vk_down
+#else
+#  define IS_VK_DOWN(a) (GetKeyState(a) < 0)
+#endif  // defined(DEBUG_VK)
+
+#endif /* WindowDbg_h__ */
diff --git a/widget/windows/nsWindowDefs.h b/widget/windows/nsWindowDefs.h
new file mode 100644
index 0000000000..320d6ef07b
--- /dev/null
+++ b/widget/windows/nsWindowDefs.h
@@ -0,0 +1,119 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WindowDefs_h__
+#define WindowDefs_h__
+
+/*
+ * nsWindowDefs - nsWindow related definitions, consts, and macros.
+ */
+
+#include "mozilla/widget/WinMessages.h"
+#include "nsBaseWidget.h"
+#include "nsdefs.h"
+#include "resource.h"
+
+/**************************************************************
+ *
+ * SECTION: defines
+ *
+ **************************************************************/
+
+// ConstrainPosition window positioning slop value
+#define kWindowPositionSlop 20
+
+// Origin of the system context menu when displayed in full screen mode
+#define MOZ_SYSCONTEXT_X_POS 20
+#define MOZ_SYSCONTEXT_Y_POS 20
+
+// Don't put more than this many rects in the dirty region, just fluff
+// out to the bounding-box if there are more
+#define MAX_RECTS_IN_REGION 100
+
+// Tablet PC Mouse Input Source
+#define TABLET_INK_SIGNATURE 0xFFFFFF00
+#define TABLET_INK_CHECK 0xFF515700
+#define TABLET_INK_TOUCH 0x00000080
+#define TABLET_INK_ID_MASK 0x0000007F
+#define MOUSE_INPUT_SOURCE() WinUtils::GetMouseInputSource()
+#define MOUSE_POINTERID() WinUtils::GetMousePointerID()
+
+/**************************************************************
+ *
+ * SECTION: constants
+ *
+ **************************************************************/
+
+/*
+ * Native windows class names
+ *
+ * ::: IMPORTANT :::
+ *
+ * External apps and drivers depend on window class names.
+ * For example, changing the window classes could break
+ * touchpad scrolling or screen readers.
+ *
+ * See bug 1776498.
+ */
+const wchar_t kClassNameHidden[] = L"MozillaHiddenWindowClass";
+const wchar_t kClassNameGeneral[] = L"MozillaWindowClass";
+const wchar_t kClassNameDialog[] = L"MozillaDialogClass";
+const wchar_t kClassNameDropShadow[] = L"MozillaDropShadowWindowClass";
+const wchar_t kClassNameTransition[] = L"MozillaTransitionWindowClass";
+
+/**************************************************************
+ *
+ * SECTION: structs
+ *
+ **************************************************************/
+
+// Used for synthesizing events
+struct KeyPair {
+  uint8_t mGeneral;
+  uint8_t mSpecific;
+  uint16_t mScanCode;
+  KeyPair(uint32_t aGeneral, uint32_t aSpecific)
+      : mGeneral(aGeneral & 0xFF),
+        mSpecific(aSpecific & 0xFF),
+        mScanCode((aGeneral & 0xFFFF0000) >> 16) {}
+  KeyPair(uint8_t aGeneral, uint8_t aSpecific, uint16_t aScanCode)
+      : mGeneral(aGeneral), mSpecific(aSpecific), mScanCode(aScanCode) {}
+};
+
+namespace mozilla {
+namespace widget {
+
+struct MSGResult {
+  // Result for the message.
+  LRESULT& mResult;
+  // If mConsumed is true, the caller shouldn't call next wndproc.
+  bool mConsumed;
+
+  explicit MSGResult(LRESULT* aResult = nullptr)
+      : mResult(aResult ? *aResult : mDefaultResult), mConsumed(false) {}
+
+ private:
+  LRESULT mDefaultResult;
+};
+
+}  // namespace widget
+}  // namespace mozilla
+
+/**************************************************************
+ *
+ * SECTION: macros
+ *
+ **************************************************************/
+
+#define NSRGB_2_COLOREF(color) \
+  RGB(NS_GET_R(color), NS_GET_G(color), NS_GET_B(color))
+#define COLOREF_2_NSRGB(color) \
+  NS_RGB(GetRValue(color), GetGValue(color), GetBValue(color))
+
+#define VERIFY_WINDOW_STYLE(s)                                         \
+  NS_ASSERTION(((s) & (WS_CHILD | WS_POPUP)) != (WS_CHILD | WS_POPUP), \
+               "WS_POPUP and WS_CHILD are mutually exclusive")
+
+#endif /* WindowDefs_h__ */
diff --git a/widget/windows/nsWindowGfx.cpp b/widget/windows/nsWindowGfx.cpp
new file mode 100644
index 0000000000..c2a91dcf6b
--- /dev/null
+++ b/widget/windows/nsWindowGfx.cpp
@@ -0,0 +1,718 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * nsWindowGfx - Painting and aceleration.
+ */
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: Includes
+ **
+ ** Include headers.
+ **
+ **************************************************************
+ **************************************************************/
+
+#include "mozilla/dom/ContentParent.h"
+
+#include "nsWindowGfx.h"
+#include "nsAppRunner.h"
+#include <windows.h>
+#include <shellapi.h>
+#include "gfxEnv.h"
+#include "gfxImageSurface.h"
+#include "gfxUtils.h"
+#include "gfxConfig.h"
+#include "gfxWindowsSurface.h"
+#include "gfxWindowsPlatform.h"
+#include "gfxDWriteFonts.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/DataSurfaceHelpers.h"
+#include "mozilla/gfx/Tools.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtrExtensions.h"
+#include "nsGfxCIID.h"
+#include "gfxContext.h"
+#include "WinUtils.h"
+#include "WinWindowOcclusionTracker.h"
+#include "nsIWidgetListener.h"
+#include "mozilla/Unused.h"
+#include "nsDebug.h"
+#include "WindowRenderer.h"
+#include "mozilla/layers/WebRenderLayerManager.h"
+
+#include "mozilla/gfx/GPUProcessManager.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "InProcessWinCompositorWidget.h"
+
+#include "nsUXThemeData.h"
+#include "nsUXThemeConstants.h"
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using namespace mozilla::layers;
+using namespace mozilla::widget;
+using namespace mozilla::plugins;
+extern mozilla::LazyLogModule gWindowsLog;
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: Variables
+ **
+ ** nsWindow Class static initializations and global variables.
+ **
+ **************************************************************
+ **************************************************************/
+
+/**************************************************************
+ *
+ * SECTION: nsWindow statics
+ *
+ **************************************************************/
+
+struct IconMetrics {
+  int32_t xMetric;
+  int32_t yMetric;
+  int32_t defaultSize;
+};
+
+// Corresponds 1:1 to the IconSizeType enum
+static IconMetrics sIconMetrics[] = {
+    {SM_CXSMICON, SM_CYSMICON, 16},  // small icon
+    {SM_CXICON, SM_CYICON, 32}       // regular icon
+};
+
+/**************************************************************
+ **************************************************************
+ **
+ ** BLOCK: nsWindow impl.
+ **
+ ** Paint related nsWindow methods.
+ **
+ **************************************************************
+ **************************************************************/
+
+// GetRegionToPaint returns the invalidated region that needs to be painted
+LayoutDeviceIntRegion nsWindow::GetRegionToPaint(bool aForceFullRepaint,
+                                                 PAINTSTRUCT ps, HDC aDC) {
+  if (aForceFullRepaint) {
+    RECT paintRect;
+    ::GetClientRect(mWnd, &paintRect);
+    return LayoutDeviceIntRegion(WinUtils::ToIntRect(paintRect));
+  }
+
+  HRGN paintRgn = ::CreateRectRgn(0, 0, 0, 0);
+  if (paintRgn != nullptr) {
+    int result = GetRandomRgn(aDC, paintRgn, SYSRGN);
+    if (result == 1) {
+      POINT pt = {0, 0};
+      ::MapWindowPoints(nullptr, mWnd, &pt, 1);
+      ::OffsetRgn(paintRgn, pt.x, pt.y);
+    }
+    LayoutDeviceIntRegion rgn(WinUtils::ConvertHRGNToRegion(paintRgn));
+    ::DeleteObject(paintRgn);
+    return rgn;
+  }
+  return LayoutDeviceIntRegion(WinUtils::ToIntRect(ps.rcPaint));
+}
+
+nsIWidgetListener* nsWindow::GetPaintListener() {
+  if (mDestroyCalled) return nullptr;
+  return mAttachedWidgetListener ? mAttachedWidgetListener : mWidgetListener;
+}
+
+void nsWindow::ForcePresent() {
+  if (mResizeState != RESIZING) {
+    if (CompositorBridgeChild* remoteRenderer = GetRemoteRenderer()) {
+      remoteRenderer->SendForcePresent(wr::RenderReasons::WIDGET);
+    }
+  }
+}
+
+bool nsWindow::OnPaint(uint32_t aNestingLevel) {
+  DeviceResetReason resetReason = DeviceResetReason::OK;
+  if (gfxWindowsPlatform::GetPlatform()->DidRenderingDeviceReset(
+          &resetReason)) {
+    gfxCriticalNote << "(nsWindow) Detected device reset: " << (int)resetReason;
+
+    gfxWindowsPlatform::GetPlatform()->UpdateRenderMode();
+
+    bool guilty;
+    switch (resetReason) {
+      case DeviceResetReason::HUNG:
+      case DeviceResetReason::RESET:
+      case DeviceResetReason::INVALID_CALL:
+        guilty = true;
+        break;
+      default:
+        guilty = false;
+        break;
+    }
+
+    GPUProcessManager::Get()->OnInProcessDeviceReset(guilty);
+
+    gfxCriticalNote << "(nsWindow) Finished device reset.";
+    return false;
+  }
+
+  PAINTSTRUCT ps;
+
+  // Avoid starting the GPU process for the initial navigator:blank window.
+  if (mIsEarlyBlankWindow) {
+    // Call BeginPaint/EndPaint or Windows will keep sending us messages.
+    ::BeginPaint(mWnd, &ps);
+    ::EndPaint(mWnd, &ps);
+    return true;
+  }
+
+  WindowRenderer* renderer = GetWindowRenderer();
+  KnowsCompositor* knowsCompositor = renderer->AsKnowsCompositor();
+  WebRenderLayerManager* layerManager = renderer->AsWebRender();
+
+  if (mClearNCEdge) {
+    // We need to clear this edge of the non-client region to black (once).
+    HDC hdc;
+    RECT rect;
+    hdc = ::GetWindowDC(mWnd);
+    ::GetWindowRect(mWnd, &rect);
+    ::MapWindowPoints(nullptr, mWnd, (LPPOINT)&rect, 2);
+    switch (mClearNCEdge.value()) {
+      case ABE_TOP:
+        rect.bottom = rect.top + kHiddenTaskbarSize;
+        break;
+      case ABE_LEFT:
+        rect.right = rect.left + kHiddenTaskbarSize;
+        break;
+      case ABE_BOTTOM:
+        rect.top = rect.bottom - kHiddenTaskbarSize;
+        break;
+      case ABE_RIGHT:
+        rect.left = rect.right - kHiddenTaskbarSize;
+        break;
+      default:
+        MOZ_ASSERT_UNREACHABLE("Invalid edge value");
+        break;
+    }
+    ::FillRect(hdc, &rect,
+               reinterpret_cast<HBRUSH>(::GetStockObject(BLACK_BRUSH)));
+    ::ReleaseDC(mWnd, hdc);
+
+    mClearNCEdge.reset();
+  }
+
+  if (knowsCompositor && layerManager &&
+      !mBounds.IsEqualEdges(mLastPaintBounds)) {
+    // Do an early async composite so that we at least have something on the
+    // screen in the right place, even if the content is out of date.
+    layerManager->ScheduleComposite(wr::RenderReasons::WIDGET);
+  }
+  mLastPaintBounds = mBounds;
+
+  // For layered translucent windows all drawing should go to memory DC and no
+  // WM_PAINT messages are normally generated. To support asynchronous painting
+  // we force generation of WM_PAINT messages by invalidating window areas with
+  // RedrawWindow, InvalidateRect or InvalidateRgn function calls.
+  const bool usingMemoryDC =
+      renderer->GetBackendType() == LayersBackend::LAYERS_NONE &&
+      mTransparencyMode == TransparencyMode::Transparent;
+
+  HDC hDC = nullptr;
+  if (usingMemoryDC) {
+    // BeginPaint/EndPaint must be called to make Windows think that invalid
+    // area is painted. Otherwise it will continue sending the same message
+    // endlessly.
+    ::BeginPaint(mWnd, &ps);
+    ::EndPaint(mWnd, &ps);
+
+    // We're guaranteed to have a widget proxy since we called
+    // GetLayerManager().
+    hDC = mBasicLayersSurface->GetTransparentDC();
+  } else {
+    hDC = ::BeginPaint(mWnd, &ps);
+  }
+
+  const bool forceRepaint = mTransparencyMode == TransparencyMode::Transparent;
+  const LayoutDeviceIntRegion region = GetRegionToPaint(forceRepaint, ps, hDC);
+
+  if (knowsCompositor && layerManager) {
+    // We need to paint to the screen even if nothing changed, since if we
+    // don't have a compositing window manager, our pixels could be stale.
+    layerManager->SetNeedsComposite(true);
+    layerManager->SendInvalidRegion(region.ToUnknownRegion());
+  }
+
+  RefPtr<nsWindow> strongThis(this);
+
+  nsIWidgetListener* listener = GetPaintListener();
+  if (listener) {
+    listener->WillPaintWindow(this);
+  }
+  // Re-get the listener since the will paint notification may have killed it.
+  listener = GetPaintListener();
+  if (!listener) {
+    return false;
+  }
+
+  if (knowsCompositor && layerManager && layerManager->NeedsComposite()) {
+    layerManager->ScheduleComposite(wr::RenderReasons::WIDGET);
+    layerManager->SetNeedsComposite(false);
+  }
+
+  bool result = true;
+  if (!region.IsEmpty() && listener) {
+    // Should probably pass in a real region here, using GetRandomRgn
+    // http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdi/clipping_4q0e.asp
+
+#ifdef WIDGET_DEBUG_OUTPUT
+    debug_DumpPaintEvent(stdout, this, region.ToUnknownRegion(), "noname",
+                         (int32_t)mWnd);
+#endif  // WIDGET_DEBUG_OUTPUT
+
+    switch (renderer->GetBackendType()) {
+      case LayersBackend::LAYERS_NONE: {
+        RefPtr<gfxASurface> targetSurface;
+
+        // don't support transparency for non-GDI rendering, for now
+        if (TransparencyMode::Transparent == mTransparencyMode) {
+          // This mutex needs to be held when EnsureTransparentSurface is
+          // called.
+          MutexAutoLock lock(mBasicLayersSurface->GetTransparentSurfaceLock());
+          targetSurface = mBasicLayersSurface->EnsureTransparentSurface();
+        }
+
+        RefPtr<gfxWindowsSurface> targetSurfaceWin;
+        if (!targetSurface) {
+          uint32_t flags = (mTransparencyMode == TransparencyMode::Opaque)
+                               ? 0
+                               : gfxWindowsSurface::FLAG_IS_TRANSPARENT;
+          targetSurfaceWin = new gfxWindowsSurface(hDC, flags);
+          targetSurface = targetSurfaceWin;
+        }
+
+        if (!targetSurface) {
+          NS_ERROR("Invalid RenderMode!");
+          return false;
+        }
+
+        RECT paintRect;
+        ::GetClientRect(mWnd, &paintRect);
+        RefPtr<DrawTarget> dt = gfxPlatform::CreateDrawTargetForSurface(
+            targetSurface, IntSize(paintRect.right - paintRect.left,
+                                   paintRect.bottom - paintRect.top));
+        if (!dt || !dt->IsValid()) {
+          gfxWarning()
+              << "nsWindow::OnPaint failed in CreateDrawTargetForSurface";
+          return false;
+        }
+
+        // don't need to double buffer with anything but GDI
+        BufferMode doubleBuffering = mozilla::layers::BufferMode::BUFFER_NONE;
+        switch (mTransparencyMode) {
+          case TransparencyMode::Transparent:
+            // If we're rendering with translucency, we're going to be
+            // rendering the whole window; make sure we clear it first
+            dt->ClearRect(
+                Rect(0.f, 0.f, dt->GetSize().width, dt->GetSize().height));
+            break;
+          default:
+            // If we're not doing translucency, then double buffer
+            doubleBuffering = mozilla::layers::BufferMode::BUFFERED;
+            break;
+        }
+
+        gfxContext thebesContext(dt);
+
+        {
+          AutoLayerManagerSetup setupLayerManager(this, &thebesContext,
+                                                  doubleBuffering);
+          result = listener->PaintWindow(this, region);
+        }
+
+        if (TransparencyMode::Transparent == mTransparencyMode) {
+          // Data from offscreen drawing surface was copied to memory bitmap of
+          // transparent bitmap. Now it can be read from memory bitmap to apply
+          // alpha channel and after that displayed on the screen.
+          mBasicLayersSurface->RedrawTransparentWindow();
+        }
+      } break;
+      case LayersBackend::LAYERS_WR: {
+        result = listener->PaintWindow(this, region);
+        if (!gfxEnv::MOZ_DISABLE_FORCE_PRESENT()) {
+          nsCOMPtr<nsIRunnable> event = NewRunnableMethod(
+              "nsWindow::ForcePresent", this, &nsWindow::ForcePresent);
+          NS_DispatchToMainThread(event);
+        }
+      } break;
+      default:
+        NS_ERROR("Unknown layers backend used!");
+        break;
+    }
+  }
+
+  if (!usingMemoryDC) {
+    ::EndPaint(mWnd, &ps);
+  }
+
+  mLastPaintEndTime = TimeStamp::Now();
+
+  // Re-get the listener since painting may have killed it.
+  listener = GetPaintListener();
+  if (listener) listener->DidPaintWindow();
+
+  if (aNestingLevel == 0 && ::GetUpdateRect(mWnd, nullptr, false)) {
+    OnPaint(1);
+  }
+
+  return result;
+}
+
+bool nsWindow::NeedsToTrackWindowOcclusionState() {
+  if (!WinWindowOcclusionTracker::Get()) {
+    return false;
+  }
+
+  if (mCompositorSession && mWindowType == WindowType::TopLevel) {
+    return true;
+  }
+
+  return false;
+}
+
+void nsWindow::NotifyOcclusionState(mozilla::widget::OcclusionState aState) {
+  MOZ_ASSERT(NeedsToTrackWindowOcclusionState());
+
+  bool isFullyOccluded = aState == mozilla::widget::OcclusionState::OCCLUDED;
+  // When window is minimized, it is not set as fully occluded.
+  if (mFrameState->GetSizeMode() == nsSizeMode_Minimized) {
+    isFullyOccluded = false;
+  }
+
+  // Don't dispatch if the new occlustion state is the same as the current
+  // state.
+  if (mIsFullyOccluded == isFullyOccluded) {
+    return;
+  }
+
+  mIsFullyOccluded = isFullyOccluded;
+
+  MOZ_LOG(gWindowsLog, LogLevel::Info,
+          ("nsWindow::NotifyOcclusionState() mIsFullyOccluded %d "
+           "mFrameState->GetSizeMode() %d",
+           mIsFullyOccluded, mFrameState->GetSizeMode()));
+
+  wr::DebugFlags flags{0};
+  flags._0 = gfx::gfxVars::WebRenderDebugFlags();
+  bool debugEnabled = bool(flags & wr::DebugFlags::WINDOW_VISIBILITY_DBG);
+  if (debugEnabled && mCompositorWidgetDelegate) {
+    mCompositorWidgetDelegate->NotifyVisibilityUpdated(
+        mFrameState->GetSizeMode(), mIsFullyOccluded);
+  }
+
+  if (mWidgetListener) {
+    mWidgetListener->OcclusionStateChanged(mIsFullyOccluded);
+  }
+}
+
+void nsWindow::MaybeEnableWindowOcclusion(bool aEnable) {
+  // WindowOcclusion is enabled/disabled only when compositor session exists.
+  // See nsWindow::NeedsToTrackWindowOcclusionState().
+  if (!mCompositorSession) {
+    return;
+  }
+
+  bool enabled = gfxConfig::IsEnabled(gfx::Feature::WINDOW_OCCLUSION);
+
+  if (aEnable) {
+    // Enable window occlusion.
+    if (enabled && NeedsToTrackWindowOcclusionState()) {
+      WinWindowOcclusionTracker::Get()->Enable(this, mWnd);
+
+      wr::DebugFlags flags{0};
+      flags._0 = gfx::gfxVars::WebRenderDebugFlags();
+      bool debugEnabled = bool(flags & wr::DebugFlags::WINDOW_VISIBILITY_DBG);
+      if (debugEnabled && mCompositorWidgetDelegate) {
+        mCompositorWidgetDelegate->NotifyVisibilityUpdated(
+            mFrameState->GetSizeMode(), mIsFullyOccluded);
+      }
+    }
+    return;
+  }
+
+  // Disable window occlusion.
+  MOZ_ASSERT(!aEnable);
+
+  if (!NeedsToTrackWindowOcclusionState()) {
+    return;
+  }
+
+  WinWindowOcclusionTracker::Get()->Disable(this, mWnd);
+  NotifyOcclusionState(OcclusionState::VISIBLE);
+
+  wr::DebugFlags flags{0};
+  flags._0 = gfx::gfxVars::WebRenderDebugFlags();
+  bool debugEnabled = bool(flags & wr::DebugFlags::WINDOW_VISIBILITY_DBG);
+  if (debugEnabled && mCompositorWidgetDelegate) {
+    mCompositorWidgetDelegate->NotifyVisibilityUpdated(
+        mFrameState->GetSizeMode(), mIsFullyOccluded);
+  }
+}
+
+// This override of CreateCompositor is to add support for sending the IPC
+// call for RequesetFxrOutput as soon as the compositor for this widget is
+// available.
+void nsWindow::CreateCompositor() {
+  nsBaseWidget::CreateCompositor();
+
+  MaybeEnableWindowOcclusion(/* aEnable */ true);
+
+  if (mRequestFxrOutputPending) {
+    GetRemoteRenderer()->SendRequestFxrOutput();
+  }
+}
+
+void nsWindow::DestroyCompositor() {
+  MaybeEnableWindowOcclusion(/* aEnable */ false);
+
+  nsBaseWidget::DestroyCompositor();
+}
+
+void nsWindow::RequestFxrOutput() {
+  if (GetRemoteRenderer() != nullptr) {
+    MOZ_CRASH("RequestFxrOutput should happen before Compositor is created.");
+  } else {
+    // The compositor isn't ready, so indicate to make the IPC call when
+    // it is available.
+    mRequestFxrOutputPending = true;
+  }
+}
+
+LayoutDeviceIntSize nsWindowGfx::GetIconMetrics(IconSizeType aSizeType) {
+  int32_t width = ::GetSystemMetrics(sIconMetrics[aSizeType].xMetric);
+  int32_t height = ::GetSystemMetrics(sIconMetrics[aSizeType].yMetric);
+
+  if (width == 0 || height == 0) {
+    width = height = sIconMetrics[aSizeType].defaultSize;
+  }
+
+  return LayoutDeviceIntSize(width, height);
+}
+
+nsresult nsWindowGfx::CreateIcon(imgIContainer* aContainer, bool aIsCursor,
+                                 LayoutDeviceIntPoint aHotspot,
+                                 LayoutDeviceIntSize aScaledSize,
+                                 HICON* aIcon) {
+  MOZ_ASSERT(aHotspot.x >= 0 && aHotspot.y >= 0);
+  MOZ_ASSERT((aScaledSize.width > 0 && aScaledSize.height > 0) ||
+             (aScaledSize.width == 0 && aScaledSize.height == 0));
+
+  // Get the image data
+  RefPtr<SourceSurface> surface = aContainer->GetFrame(
+      imgIContainer::FRAME_CURRENT,
+      imgIContainer::FLAG_SYNC_DECODE | imgIContainer::FLAG_ASYNC_NOTIFY);
+  NS_ENSURE_TRUE(surface, NS_ERROR_NOT_AVAILABLE);
+
+  IntSize frameSize = surface->GetSize();
+  if (frameSize.IsEmpty()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  IntSize iconSize(aScaledSize.width, aScaledSize.height);
+  if (iconSize == IntSize(0, 0)) {  // use frame's intrinsic size
+    iconSize = frameSize;
+  }
+
+  RefPtr<DataSourceSurface> dataSurface;
+  bool mappedOK;
+  DataSourceSurface::MappedSurface map;
+
+  if (iconSize != frameSize) {
+    // Scale the surface
+    dataSurface =
+        Factory::CreateDataSourceSurface(iconSize, SurfaceFormat::B8G8R8A8);
+    NS_ENSURE_TRUE(dataSurface, NS_ERROR_FAILURE);
+    mappedOK = dataSurface->Map(DataSourceSurface::MapType::READ_WRITE, &map);
+    NS_ENSURE_TRUE(mappedOK, NS_ERROR_FAILURE);
+
+    RefPtr<DrawTarget> dt = Factory::CreateDrawTargetForData(
+        BackendType::CAIRO, map.mData, dataSurface->GetSize(), map.mStride,
+        SurfaceFormat::B8G8R8A8);
+    if (!dt) {
+      gfxWarning()
+          << "nsWindowGfx::CreatesIcon failed in CreateDrawTargetForData";
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+    dt->DrawSurface(surface, Rect(0, 0, iconSize.width, iconSize.height),
+                    Rect(0, 0, frameSize.width, frameSize.height),
+                    DrawSurfaceOptions(),
+                    DrawOptions(1.0f, CompositionOp::OP_SOURCE));
+  } else if (surface->GetFormat() != SurfaceFormat::B8G8R8A8) {
+    // Convert format to SurfaceFormat::B8G8R8A8
+    dataSurface = gfxUtils::CopySurfaceToDataSourceSurfaceWithFormat(
+        surface, SurfaceFormat::B8G8R8A8);
+    NS_ENSURE_TRUE(dataSurface, NS_ERROR_FAILURE);
+    mappedOK = dataSurface->Map(DataSourceSurface::MapType::READ, &map);
+  } else {
+    dataSurface = surface->GetDataSurface();
+    NS_ENSURE_TRUE(dataSurface, NS_ERROR_FAILURE);
+    mappedOK = dataSurface->Map(DataSourceSurface::MapType::READ, &map);
+  }
+  NS_ENSURE_TRUE(dataSurface && mappedOK, NS_ERROR_FAILURE);
+  MOZ_ASSERT(dataSurface->GetFormat() == SurfaceFormat::B8G8R8A8);
+
+  uint8_t* data = nullptr;
+  UniquePtr<uint8_t[]> autoDeleteArray;
+  if (map.mStride == BytesPerPixel(dataSurface->GetFormat()) * iconSize.width) {
+    // Mapped data is already packed
+    data = map.mData;
+  } else {
+    // We can't use map.mData since the pixels are not packed (as required by
+    // CreateDIBitmap, which is called under the DataToBitmap call below).
+    //
+    // We must unmap before calling SurfaceToPackedBGRA because it needs access
+    // to the pixel data.
+    dataSurface->Unmap();
+    map.mData = nullptr;
+
+    autoDeleteArray = SurfaceToPackedBGRA(dataSurface);
+    data = autoDeleteArray.get();
+    NS_ENSURE_TRUE(data, NS_ERROR_FAILURE);
+  }
+
+  HBITMAP bmp = DataToBitmap(data, iconSize.width, -iconSize.height, 32);
+  uint8_t* a1data = Data32BitTo1Bit(data, iconSize.width, iconSize.height);
+  if (map.mData) {
+    dataSurface->Unmap();
+  }
+  if (!a1data) {
+    return NS_ERROR_FAILURE;
+  }
+
+  HBITMAP mbmp = DataToBitmap(a1data, iconSize.width, -iconSize.height, 1);
+  free(a1data);
+
+  ICONINFO info = {0};
+  info.fIcon = !aIsCursor;
+  info.xHotspot = aHotspot.x;
+  info.yHotspot = aHotspot.y;
+  info.hbmMask = mbmp;
+  info.hbmColor = bmp;
+
+  HCURSOR icon = ::CreateIconIndirect(&info);
+  ::DeleteObject(mbmp);
+  ::DeleteObject(bmp);
+  if (!icon) return NS_ERROR_FAILURE;
+  *aIcon = icon;
+  return NS_OK;
+}
+
+// Adjust cursor image data
+uint8_t* nsWindowGfx::Data32BitTo1Bit(uint8_t* aImageData, uint32_t aWidth,
+                                      uint32_t aHeight) {
+  // We need (aWidth + 7) / 8 bytes plus zero-padding up to a multiple of
+  // 4 bytes for each row (HBITMAP requirement). Bug 353553.
+  uint32_t outBpr = ((aWidth + 31) / 8) & ~3;
+
+  // Allocate and clear mask buffer
+  uint8_t* outData = (uint8_t*)calloc(outBpr, aHeight);
+  if (!outData) return nullptr;
+
+  int32_t* imageRow = (int32_t*)aImageData;
+  for (uint32_t curRow = 0; curRow < aHeight; curRow++) {
+    uint8_t* outRow = outData + curRow * outBpr;
+    uint8_t mask = 0x80;
+    for (uint32_t curCol = 0; curCol < aWidth; curCol++) {
+      // Use sign bit to test for transparency, as alpha byte is highest byte
+      if (*imageRow++ < 0) *outRow |= mask;
+
+      mask >>= 1;
+      if (!mask) {
+        outRow++;
+        mask = 0x80;
+      }
+    }
+  }
+
+  return outData;
+}
+
+/**
+ * Convert the given image data to a HBITMAP. If the requested depth is
+ * 32 bit, a bitmap with an alpha channel will be returned.
+ *
+ * @param aImageData The image data to convert. Must use the format accepted
+ *                   by CreateDIBitmap.
+ * @param aWidth     With of the bitmap, in pixels.
+ * @param aHeight    Height of the image, in pixels.
+ * @param aDepth     Image depth, in bits. Should be one of 1, 24 and 32.
+ *
+ * @return The HBITMAP representing the image. Caller should call
+ *         DeleteObject when done with the bitmap.
+ *         On failure, nullptr will be returned.
+ */
+HBITMAP nsWindowGfx::DataToBitmap(uint8_t* aImageData, uint32_t aWidth,
+                                  uint32_t aHeight, uint32_t aDepth) {
+  HDC dc = ::GetDC(nullptr);
+
+  if (aDepth == 32) {
+    // Alpha channel. We need the new header.
+    BITMAPV4HEADER head = {0};
+    head.bV4Size = sizeof(head);
+    head.bV4Width = aWidth;
+    head.bV4Height = aHeight;
+    head.bV4Planes = 1;
+    head.bV4BitCount = aDepth;
+    head.bV4V4Compression = BI_BITFIELDS;
+    head.bV4SizeImage = 0;  // Uncompressed
+    head.bV4XPelsPerMeter = 0;
+    head.bV4YPelsPerMeter = 0;
+    head.bV4ClrUsed = 0;
+    head.bV4ClrImportant = 0;
+
+    head.bV4RedMask = 0x00FF0000;
+    head.bV4GreenMask = 0x0000FF00;
+    head.bV4BlueMask = 0x000000FF;
+    head.bV4AlphaMask = 0xFF000000;
+
+    HBITMAP bmp = ::CreateDIBitmap(
+        dc, reinterpret_cast<CONST BITMAPINFOHEADER*>(&head), CBM_INIT,
+        aImageData, reinterpret_cast<CONST BITMAPINFO*>(&head), DIB_RGB_COLORS);
+    ::ReleaseDC(nullptr, dc);
+    return bmp;
+  }
+
+  char reserved_space[sizeof(BITMAPINFOHEADER) + sizeof(RGBQUAD) * 2];
+  BITMAPINFOHEADER& head = *(BITMAPINFOHEADER*)reserved_space;
+
+  head.biSize = sizeof(BITMAPINFOHEADER);
+  head.biWidth = aWidth;
+  head.biHeight = aHeight;
+  head.biPlanes = 1;
+  head.biBitCount = (WORD)aDepth;
+  head.biCompression = BI_RGB;
+  head.biSizeImage = 0;  // Uncompressed
+  head.biXPelsPerMeter = 0;
+  head.biYPelsPerMeter = 0;
+  head.biClrUsed = 0;
+  head.biClrImportant = 0;
+
+  BITMAPINFO& bi = *(BITMAPINFO*)reserved_space;
+
+  if (aDepth == 1) {
+    RGBQUAD black = {0, 0, 0, 0};
+    RGBQUAD white = {255, 255, 255, 0};
+
+    bi.bmiColors[0] = white;
+    bi.bmiColors[1] = black;
+  }
+
+  HBITMAP bmp =
+      ::CreateDIBitmap(dc, &head, CBM_INIT, aImageData, &bi, DIB_RGB_COLORS);
+  ::ReleaseDC(nullptr, dc);
+  return bmp;
+}
diff --git a/widget/windows/nsWindowGfx.h b/widget/windows/nsWindowGfx.h
new file mode 100644
index 0000000000..0d5fd9e01a
--- /dev/null
+++ b/widget/windows/nsWindowGfx.h
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WindowGfx_h__
+#define WindowGfx_h__
+
+/*
+ * nsWindowGfx - Painting and aceleration.
+ */
+
+#include "nsWindow.h"
+#include <imgIContainer.h>
+
+class nsWindowGfx {
+ public:
+  enum IconSizeType { kSmallIcon, kRegularIcon };
+  static mozilla::LayoutDeviceIntSize GetIconMetrics(IconSizeType aSizeType);
+  static nsresult CreateIcon(imgIContainer* aContainer, bool aIsCursor,
+                             mozilla::LayoutDeviceIntPoint aHotspot,
+                             mozilla::LayoutDeviceIntSize aScaledSize,
+                             HICON* aIcon);
+
+ private:
+  /**
+   * Cursor helpers
+   */
+  static uint8_t* Data32BitTo1Bit(uint8_t* aImageData, uint32_t aWidth,
+                                  uint32_t aHeight);
+  static HBITMAP DataToBitmap(uint8_t* aImageData, uint32_t aWidth,
+                              uint32_t aHeight, uint32_t aDepth);
+};
+
+#endif  // WindowGfx_h__
diff --git a/widget/windows/nsWindowLoggedMessages.cpp b/widget/windows/nsWindowLoggedMessages.cpp
new file mode 100644
index 0000000000..ac0f05a875
--- /dev/null
+++ b/widget/windows/nsWindowLoggedMessages.cpp
@@ -0,0 +1,307 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <windef.h>
+#include <winuser.h>
+#include "mozilla/StaticPrefs_storage.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "nsWindowLoggedMessages.h"
+#include "nsWindow.h"
+#include "WinUtils.h"
+#include <map>
+#include <algorithm>
+
+namespace mozilla::widget {
+
+// NCCALCSIZE_PARAMS and WINDOWPOS are relatively large structures, so store
+// them as a pointer to save memory
+using NcCalcSizeVariantData =
+    Variant<UniquePtr<std::pair<NCCALCSIZE_PARAMS, WINDOWPOS>>, RECT>;
+// to save memory, hold the raw data and only convert to string
+// when requested
+using MessageSpecificData =
+    Variant<std::pair<WPARAM, LPARAM>,  // WM_SIZE, WM_MOVE
+            WINDOWPOS,  // WM_WINDOWPOSCHANGING, WM_WINDOWPOSCHANGED
+            std::pair<WPARAM, RECT>,      // WM_SIZING, WM_DPICHANGED, WM_MOVING
+            std::pair<WPARAM, nsString>,  // WM_SETTINGCHANGE
+            std::pair<bool, NcCalcSizeVariantData>,  // WM_NCCALCSIZE
+            MINMAXINFO                               // WM_GETMINMAXINFO
+            >;
+
+struct WindowMessageData {
+  long mEventCounter;
+  bool mIsPreEvent;
+  MessageSpecificData mSpecificData;
+  mozilla::Maybe<bool> mResult;
+  LRESULT mRetValue;
+  WindowMessageData(long eventCounter, bool isPreEvent,
+                    MessageSpecificData&& specificData,
+                    mozilla::Maybe<bool> result, LRESULT retValue)
+      : mEventCounter(eventCounter),
+        mIsPreEvent(isPreEvent),
+        mSpecificData(std::move(specificData)),
+        mResult(result),
+        mRetValue(retValue) {}
+  // Disallow copy constructor/operator since MessageSpecificData has a
+  // UniquePtr
+  WindowMessageData(const WindowMessageData&) = delete;
+  WindowMessageData& operator=(const WindowMessageData&) = delete;
+  WindowMessageData(WindowMessageData&&) = default;
+  WindowMessageData& operator=(WindowMessageData&&) = default;
+};
+
+struct WindowMessageDataSortKey {
+  long mEventCounter;
+  bool mIsPreEvent;
+  explicit WindowMessageDataSortKey(const WindowMessageData& data)
+      : mEventCounter(data.mEventCounter), mIsPreEvent(data.mIsPreEvent) {}
+  bool operator<(const WindowMessageDataSortKey& other) const {
+    if (mEventCounter < other.mEventCounter) {
+      return true;
+    }
+    if (other.mEventCounter < mEventCounter) {
+      return false;
+    }
+    if (mIsPreEvent && !other.mIsPreEvent) {
+      return true;
+    }
+    if (other.mIsPreEvent && !mIsPreEvent) {
+      return false;
+    }
+    // they're equal
+    return false;
+  }
+};
+
+struct CircularMessageBuffer {
+  // Only used when the vector is at its maximum size
+  size_t mNextFreeIndex = 0;
+  std::vector<WindowMessageData> mMessages;
+};
+static std::map<HWND, std::map<UINT, CircularMessageBuffer>> gWindowMessages;
+
+static HWND GetHwndFromWidget(nsIWidget* windowWidget) {
+  nsWindow* window = static_cast<nsWindow*>(windowWidget);
+  return window->GetWindowHandle();
+}
+
+MessageSpecificData MakeMessageSpecificData(UINT event, WPARAM wParam,
+                                            LPARAM lParam) {
+  // Since we store this data for every message we log, make sure it's of a
+  // reasonable size. Keep in mind we're storing up to 10 (number of message
+  // types)
+  // * 6 (default number of messages per type to keep) of these messages per
+  // window.
+  static_assert(sizeof(MessageSpecificData) <= 48);
+  switch (event) {
+    case WM_SIZE:
+    case WM_MOVE:
+      return MessageSpecificData(std::make_pair(wParam, lParam));
+    case WM_WINDOWPOSCHANGING:
+    case WM_WINDOWPOSCHANGED: {
+      LPWINDOWPOS windowPosPtr = reinterpret_cast<LPWINDOWPOS>(lParam);
+      WINDOWPOS windowPos = *windowPosPtr;
+      return MessageSpecificData(std::move(windowPos));
+    }
+    case WM_SIZING:
+    case WM_DPICHANGED:
+    case WM_MOVING: {
+      LPRECT rectPtr = reinterpret_cast<LPRECT>(lParam);
+      RECT rect = *rectPtr;
+      return MessageSpecificData(std::make_pair(wParam, std::move(rect)));
+    }
+    case WM_SETTINGCHANGE: {
+      LPCWSTR wideStrPtr = reinterpret_cast<LPCWSTR>(lParam);
+      nsString str(wideStrPtr);
+      return MessageSpecificData(std::make_pair(wParam, std::move(str)));
+    }
+    case WM_NCCALCSIZE: {
+      bool shouldIndicateValidArea = wParam == TRUE;
+      if (shouldIndicateValidArea) {
+        LPNCCALCSIZE_PARAMS ncCalcSizeParamsPtr =
+            reinterpret_cast<LPNCCALCSIZE_PARAMS>(lParam);
+        NCCALCSIZE_PARAMS ncCalcSizeParams = *ncCalcSizeParamsPtr;
+        WINDOWPOS windowPos = *ncCalcSizeParams.lppos;
+        UniquePtr<std::pair<NCCALCSIZE_PARAMS, WINDOWPOS>> ncCalcSizeData =
+            MakeUnique<std::pair<NCCALCSIZE_PARAMS, WINDOWPOS>>(
+                std::pair(std::move(ncCalcSizeParams), std::move(windowPos)));
+        return MessageSpecificData(
+            std::make_pair(shouldIndicateValidArea,
+                           NcCalcSizeVariantData(std::move(ncCalcSizeData))));
+      } else {
+        LPRECT rectPtr = reinterpret_cast<LPRECT>(lParam);
+        RECT rect = *rectPtr;
+        return MessageSpecificData(std::make_pair(
+            shouldIndicateValidArea, NcCalcSizeVariantData(std::move(rect))));
+      }
+    }
+    case WM_GETMINMAXINFO: {
+      PMINMAXINFO minMaxInfoPtr = reinterpret_cast<PMINMAXINFO>(lParam);
+      MINMAXINFO minMaxInfo = *minMaxInfoPtr;
+      return MessageSpecificData(std::move(minMaxInfo));
+    }
+    default:
+      MOZ_ASSERT_UNREACHABLE(
+          "Unhandled message type in MakeMessageSpecificData");
+      return MessageSpecificData(std::make_pair(wParam, lParam));
+  }
+}
+
+void AppendFriendlyMessageSpecificData(nsCString& str, UINT event,
+                                       bool isPreEvent,
+                                       const MessageSpecificData& data) {
+  switch (event) {
+    case WM_SIZE: {
+      const auto& params = data.as<std::pair<WPARAM, LPARAM>>();
+      nsAutoCString tempStr =
+          WmSizeParamInfo(params.first, params.second, isPreEvent);
+      str.AppendASCII(tempStr);
+      break;
+    }
+    case WM_MOVE: {
+      const auto& params = data.as<std::pair<WPARAM, LPARAM>>();
+      XLowWordYHighWordParamInfo(str, params.second, "upperLeft", isPreEvent);
+      break;
+    }
+    case WM_WINDOWPOSCHANGING:
+    case WM_WINDOWPOSCHANGED: {
+      const auto& params = data.as<WINDOWPOS>();
+      WindowPosParamInfo(str, reinterpret_cast<uint64_t>(&params),
+                         "newSizeAndPos", isPreEvent);
+      break;
+    }
+    case WM_SIZING: {
+      const auto& params = data.as<std::pair<WPARAM, RECT>>();
+      WindowEdgeParamInfo(str, params.first, "edge", isPreEvent);
+      str.AppendASCII(" ");
+      RectParamInfo(str, reinterpret_cast<uint64_t>(&params.second), "rect",
+                    isPreEvent);
+      break;
+    }
+    case WM_DPICHANGED: {
+      const auto& params = data.as<std::pair<WPARAM, RECT>>();
+      XLowWordYHighWordParamInfo(str, params.first, "newDPI", isPreEvent);
+      str.AppendASCII(" ");
+      RectParamInfo(str, reinterpret_cast<uint64_t>(&params.second),
+                    "suggestedSizeAndPos", isPreEvent);
+      break;
+    }
+    case WM_MOVING: {
+      const auto& params = data.as<std::pair<WPARAM, RECT>>();
+      RectParamInfo(str, reinterpret_cast<uint64_t>(&params.second), "rect",
+                    isPreEvent);
+      break;
+    }
+    case WM_SETTINGCHANGE: {
+      const auto& params = data.as<std::pair<WPARAM, nsString>>();
+      UiActionParamInfo(str, params.first, "uiAction", isPreEvent);
+      str.AppendASCII(" ");
+      WideStringParamInfo(
+          str,
+          reinterpret_cast<uint64_t>((const wchar_t*)(params.second.Data())),
+          "paramChanged", isPreEvent);
+      break;
+    }
+    case WM_NCCALCSIZE: {
+      const auto& params = data.as<std::pair<bool, NcCalcSizeVariantData>>();
+      bool shouldIndicateValidArea = params.first;
+      if (shouldIndicateValidArea) {
+        const auto& validAreaParams =
+            params.second
+                .as<UniquePtr<std::pair<NCCALCSIZE_PARAMS, WINDOWPOS>>>();
+        // Make pointer point to the cached data
+        validAreaParams->first.lppos = &validAreaParams->second;
+        nsAutoCString tempStr = WmNcCalcSizeParamInfo(
+            TRUE, reinterpret_cast<uint64_t>(&validAreaParams->first),
+            isPreEvent);
+        str.AppendASCII(tempStr);
+      } else {
+        RECT rect = params.second.as<RECT>();
+        nsAutoCString tempStr = WmNcCalcSizeParamInfo(
+            FALSE, reinterpret_cast<uint64_t>(&rect), isPreEvent);
+        str.AppendASCII(tempStr);
+      }
+      break;
+    }
+    case WM_GETMINMAXINFO: {
+      const auto& params = data.as<MINMAXINFO>();
+      MinMaxInfoParamInfo(str, reinterpret_cast<uint64_t>(&params), "",
+                          isPreEvent);
+      break;
+    }
+    default:
+      MOZ_ASSERT(false,
+                 "Unhandled message type in AppendFriendlyMessageSpecificData");
+      str.AppendASCII("???");
+  }
+}
+
+nsCString MakeFriendlyMessage(UINT event, bool isPreEvent, long eventCounter,
+                              const MessageSpecificData& data,
+                              mozilla::Maybe<bool> result, LRESULT retValue) {
+  nsCString str;
+  const char* eventName = mozilla::widget::WinUtils::WinEventToEventName(event);
+  MOZ_ASSERT(eventName, "Unknown event name in MakeFriendlyMessage");
+  eventName = eventName ? eventName : "(unknown)";
+  str.AppendPrintf("%6ld %04x (%s) - ", eventCounter, event, eventName);
+  AppendFriendlyMessageSpecificData(str, event, isPreEvent, data);
+  const char* resultMsg =
+      result.isSome() ? (result.value() ? "true" : "false") : "initial call";
+  str.AppendPrintf(" 0x%08llX (%s)",
+                   result.isSome() ? static_cast<uint64_t>(retValue) : 0,
+                   resultMsg);
+  return str;
+}
+
+void WindowClosed(HWND hwnd) { gWindowMessages.erase(hwnd); }
+
+void LogWindowMessage(HWND hwnd, UINT event, bool isPreEvent, long eventCounter,
+                      WPARAM wParam, LPARAM lParam, mozilla::Maybe<bool> result,
+                      LRESULT retValue) {
+  auto& hwndMessages = gWindowMessages[hwnd];
+  auto& hwndWindowMessages = hwndMessages[event];
+  WindowMessageData messageData = {
+      eventCounter, isPreEvent, MakeMessageSpecificData(event, wParam, lParam),
+      result, retValue};
+  uint32_t numberOfMessagesToKeep =
+      StaticPrefs::widget_windows_messages_to_log();
+  if (hwndWindowMessages.mMessages.size() < numberOfMessagesToKeep) {
+    // haven't reached limit yet
+    hwndWindowMessages.mMessages.push_back(std::move(messageData));
+  } else {
+    hwndWindowMessages.mMessages[hwndWindowMessages.mNextFreeIndex] =
+        std::move(messageData);
+  }
+  hwndWindowMessages.mNextFreeIndex =
+      (hwndWindowMessages.mNextFreeIndex + 1) % numberOfMessagesToKeep;
+}
+
+void GetLatestWindowMessages(RefPtr<nsIWidget> windowWidget,
+                             nsTArray<nsCString>& messages) {
+  HWND hwnd = GetHwndFromWidget(windowWidget);
+  const auto& rawMessages = gWindowMessages[hwnd];
+  nsTArray<std::pair<WindowMessageDataSortKey, nsCString>>
+      sortKeyAndMessageArray;
+  sortKeyAndMessageArray.SetCapacity(
+      rawMessages.size() * StaticPrefs::widget_windows_messages_to_log());
+  for (const auto& eventAndMessage : rawMessages) {
+    for (const auto& messageData : eventAndMessage.second.mMessages) {
+      nsCString message = MakeFriendlyMessage(
+          eventAndMessage.first, messageData.mIsPreEvent,
+          messageData.mEventCounter, messageData.mSpecificData,
+          messageData.mResult, messageData.mRetValue);
+      WindowMessageDataSortKey sortKey(messageData);
+      sortKeyAndMessageArray.AppendElement(
+          std::make_pair(sortKey, std::move(message)));
+    }
+  }
+  std::sort(sortKeyAndMessageArray.begin(), sortKeyAndMessageArray.end());
+  messages.SetCapacity(sortKeyAndMessageArray.Length());
+  for (const std::pair<WindowMessageDataSortKey, nsCString>& entry :
+       sortKeyAndMessageArray) {
+    messages.AppendElement(std::move(entry.second));
+  }
+}
+}  // namespace mozilla::widget
diff --git a/widget/windows/nsWindowLoggedMessages.h b/widget/windows/nsWindowLoggedMessages.h
new file mode 100644
index 0000000000..c0ea632bb0
--- /dev/null
+++ b/widget/windows/nsWindowLoggedMessages.h
@@ -0,0 +1,26 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WindowLoggedMessages_h__
+#define WindowLoggedMessages_h__
+
+#include "minwindef.h"
+#include "wtypes.h"
+
+#include "nsIWidget.h"
+#include "nsStringFwd.h"
+
+namespace mozilla::widget {
+
+void LogWindowMessage(HWND hwnd, UINT event, bool isPreEvent, long eventCounter,
+                      WPARAM wParam, LPARAM lParam, mozilla::Maybe<bool> result,
+                      LRESULT retValue);
+void WindowClosed(HWND hwnd);
+void GetLatestWindowMessages(RefPtr<nsIWidget> windowWidget,
+                             nsTArray<nsCString>& messages);
+
+}  // namespace mozilla::widget
+
+#endif /* WindowLoggedMessages */
diff --git a/widget/windows/nsWindowTaskbarConcealer.cpp b/widget/windows/nsWindowTaskbarConcealer.cpp
new file mode 100644
index 0000000000..b2b6b13a1d
--- /dev/null
+++ b/widget/windows/nsWindowTaskbarConcealer.cpp
@@ -0,0 +1,384 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsWindowTaskbarConcealer.h"
+
+#include "nsIWinTaskbar.h"
+#define NS_TASKBAR_CONTRACTID "@mozilla.org/windows-taskbar;1"
+
+#include "mozilla/Logging.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "WinUtils.h"
+
+using namespace mozilla;
+
+/**
+ * TaskbarConcealerImpl
+ *
+ * Implement Windows-fullscreen marking.
+ *
+ * nsWindow::TaskbarConcealer implements logic determining _whether_ to tell
+ * Windows that a given window is fullscreen. TaskbarConcealerImpl performs the
+ * platform-specific work of actually communicating that fact to Windows.
+ *
+ * (This object is not persistent; it's constructed on the stack when needed.)
+ */
+struct TaskbarConcealerImpl {
+  void MarkAsHidingTaskbar(HWND aWnd, bool aMark);
+
+ private:
+  nsCOMPtr<nsIWinTaskbar> mTaskbarInfo;
+};
+
+/**
+ * nsWindow::TaskbarConcealer
+ *
+ * Issue taskbar-hide requests to the OS as needed.
+ */
+
+/*
+  Per MSDN [0], one should mark and unmark fullscreen windows via the
+  ITaskbarList2::MarkFullscreenWindow method. Unfortunately, Windows pays less
+  attention to this than one might prefer -- in particular, it typically fails
+  to show the taskbar when switching focus from a window marked as fullscreen to
+  one not thus marked. [1]
+
+  Experimentation has (so far) suggested that its behavior is reasonable when
+  switching between multiple monitors, or between a set of windows which are all
+  from different processes [2]. This leaves us to handle the same-monitor, same-
+  process case.
+
+  Rather than do anything subtle here, we take the blanket approach of simply
+  listening for every potentially-relevant state change, and then explicitly
+  marking or unmarking every potentially-visible toplevel window.
+
+  ----
+
+  [0] Relevant link:
+      https://docs.microsoft.com/en-us/windows/win32/api/shobjidl_core/nf-shobjidl_core-itaskbarlist2-markfullscreenwindow
+
+      The "NonRudeHWND" property described therein doesn't help with anything
+      in this comment, unfortunately. (See its use in MarkAsHidingTaskbar for
+      more details.)
+
+  [1] This is an oversimplification; Windows' actual behavior here is...
+      complicated. See bug 1732517 comment 6 for some examples.
+
+  [2] A comment in Chromium asserts that this is actually different threads. For
+      us, of course, that makes no difference.
+      https://github.com/chromium/chromium/blob/2b822268bd3/ui/views/win/hwnd_message_handler.cc#L1342
+*/
+
+/**************************************************************
+ *
+ * SECTION: TaskbarConcealer utilities
+ *
+ **************************************************************/
+
+static mozilla::LazyLogModule sTaskbarConcealerLog("TaskbarConcealer");
+
+// Map of all relevant Gecko windows, along with the monitor on which each
+// window was last known to be located.
+/* static */
+nsTHashMap<HWND, HMONITOR> nsWindow::TaskbarConcealer::sKnownWindows;
+
+// Returns Nothing if the window in question is irrelevant (for any reason),
+// or Some(the window's current state) otherwise.
+/* static */
+Maybe<nsWindow::TaskbarConcealer::WindowState>
+nsWindow::TaskbarConcealer::GetWindowState(HWND aWnd) {
+  // Classical Win32 visibility conditions.
+  if (!::IsWindowVisible(aWnd)) {
+    return Nothing();
+  }
+  if (::IsIconic(aWnd)) {
+    return Nothing();
+  }
+
+  // Non-nsWindow windows associated with this thread may include file dialogs
+  // and IME input popups.
+  nsWindow* pWin = widget::WinUtils::GetNSWindowPtr(aWnd);
+  if (!pWin) {
+    return Nothing();
+  }
+
+  // nsWindows of other window-classes include tooltips and drop-shadow-bearing
+  // menus.
+  if (pWin->mWindowType != WindowType::TopLevel) {
+    return Nothing();
+  }
+
+  // Cloaked windows are (presumably) on a different virtual desktop.
+  // https://devblogs.microsoft.com/oldnewthing/20200302-00/?p=103507
+  if (pWin->mIsCloaked) {
+    return Nothing();
+  }
+
+  return Some(
+      WindowState{::MonitorFromWindow(aWnd, MONITOR_DEFAULTTONULL),
+                  pWin->mFrameState->GetSizeMode() == nsSizeMode_Fullscreen});
+}
+
+/**************************************************************
+ *
+ * SECTION: TaskbarConcealer::UpdateAllState
+ *
+ **************************************************************/
+
+// Update all Windows-fullscreen-marking state and internal caches to represent
+// the current state of the system.
+/* static */
+void nsWindow::TaskbarConcealer::UpdateAllState(
+    HWND destroyedHwnd /* = nullptr */
+) {
+  // sKnownWindows is otherwise-unprotected shared state
+  MOZ_ASSERT(NS_IsMainThread(),
+             "TaskbarConcealer can only be used from the main thread!");
+
+  if (MOZ_LOG_TEST(sTaskbarConcealerLog, LogLevel::Info)) {
+    static size_t sLogCounter = 0;
+    MOZ_LOG(sTaskbarConcealerLog, LogLevel::Info,
+            ("Calling UpdateAllState() for the %zuth time", sLogCounter++));
+
+    MOZ_LOG(sTaskbarConcealerLog, LogLevel::Info, ("Last known state:"));
+    if (sKnownWindows.IsEmpty()) {
+      MOZ_LOG(sTaskbarConcealerLog, LogLevel::Info,
+              ("  none (no windows known)"));
+    } else {
+      for (const auto& entry : sKnownWindows) {
+        MOZ_LOG(
+            sTaskbarConcealerLog, LogLevel::Info,
+            ("  window %p was on monitor %p", entry.GetKey(), entry.GetData()));
+      }
+    }
+  }
+
+  // Array of all our potentially-relevant HWNDs, in Z-order (topmost first),
+  // along with their associated relevant state.
+  struct Item {
+    HWND hwnd;
+    HMONITOR monitor;
+    bool isGkFullscreen;
+  };
+  const nsTArray<Item> windows = [&] {
+    nsTArray<Item> windows;
+
+    // USE OF UNDOCUMENTED BEHAVIOR: The EnumWindows family of functions
+    // enumerates windows in Z-order, topmost first. (This has been true since
+    // at least Windows 2000, and possibly since Windows 3.0.)
+    //
+    // It's necessarily unreliable if windows are reordered while being
+    // enumerated; but in that case we'll get a message informing us of that
+    // fact, and can redo our state-calculations then.
+    //
+    // There exists no documented interface to acquire this information (other
+    // than ::GetWindow(), which is racy).
+    mozilla::EnumerateThreadWindows([&](HWND hwnd) {
+      // Depending on details of window-destruction that probably shouldn't be
+      // relied on, this HWND may or may not still be in the window list.
+      // Pretend it's not.
+      if (hwnd == destroyedHwnd) {
+        return;
+      }
+
+      const auto maybeState = GetWindowState(hwnd);
+      if (!maybeState) {
+        return;
+      }
+      const WindowState& state = *maybeState;
+
+      windows.AppendElement(Item{.hwnd = hwnd,
+                                 .monitor = state.monitor,
+                                 .isGkFullscreen = state.isGkFullscreen});
+    });
+
+    return windows;
+  }();
+
+  // Relevant monitors are exactly those with relevant windows.
+  const nsTHashSet<HMONITOR> relevantMonitors = [&]() {
+    nsTHashSet<HMONITOR> relevantMonitors;
+    for (const Item& item : windows) {
+      relevantMonitors.Insert(item.monitor);
+    }
+    return relevantMonitors;
+  }();
+
+  // Update the cached mapping from windows to monitors. (This is only used as
+  // an optimization in TaskbarConcealer::OnWindowPosChanged().)
+  sKnownWindows.Clear();
+  for (const Item& item : windows) {
+    MOZ_LOG(
+        sTaskbarConcealerLog, LogLevel::Debug,
+        ("Found relevant window %p on monitor %p", item.hwnd, item.monitor));
+    sKnownWindows.InsertOrUpdate(item.hwnd, item.monitor);
+  }
+
+  // Auxiliary function. Does what it says on the tin.
+  const auto FindUppermostWindowOn = [&windows](HMONITOR aMonitor) -> HWND {
+    for (const Item& item : windows) {
+      if (item.monitor == aMonitor) {
+        MOZ_LOG(sTaskbarConcealerLog, LogLevel::Info,
+                ("on monitor %p, uppermost relevant HWND is %p", aMonitor,
+                 item.hwnd));
+        return item.hwnd;
+      }
+    }
+
+    // This should never happen, since we're drawing our monitor-set from the
+    // set of relevant windows.
+    MOZ_LOG(sTaskbarConcealerLog, LogLevel::Warning,
+            ("on monitor %p, no relevant windows were found", aMonitor));
+    return nullptr;
+  };
+
+  TaskbarConcealerImpl impl;
+
+  // Mark all relevant windows as not hiding the taskbar, unless they're both
+  // Gecko-fullscreen and the uppermost relevant window on their monitor.
+  for (HMONITOR monitor : relevantMonitors) {
+    const HWND topmost = FindUppermostWindowOn(monitor);
+
+    for (const Item& item : windows) {
+      if (item.monitor != monitor) continue;
+      impl.MarkAsHidingTaskbar(item.hwnd,
+                               item.isGkFullscreen && item.hwnd == topmost);
+    }
+  }
+}  // nsWindow::TaskbarConcealer::UpdateAllState()
+
+// Mark this window as requesting to occlude the taskbar. (The caller is
+// responsible for keeping any local state up-to-date.)
+void TaskbarConcealerImpl::MarkAsHidingTaskbar(HWND aWnd, bool aMark) {
+  const char* const sMark = aMark ? "true" : "false";
+
+  if (!mTaskbarInfo) {
+    mTaskbarInfo = do_GetService(NS_TASKBAR_CONTRACTID);
+
+    if (!mTaskbarInfo) {
+      MOZ_LOG(
+          sTaskbarConcealerLog, LogLevel::Warning,
+          ("could not acquire IWinTaskbar (aWnd %p, aMark %s)", aWnd, sMark));
+      return;
+    }
+  }
+
+  MOZ_LOG(sTaskbarConcealerLog, LogLevel::Info,
+          ("Calling PrepareFullScreen(%p, %s)", aWnd, sMark));
+
+  const nsresult hr = mTaskbarInfo->PrepareFullScreen(aWnd, aMark);
+
+  if (FAILED(hr)) {
+    MOZ_LOG(sTaskbarConcealerLog, LogLevel::Error,
+            ("Call to PrepareFullScreen(%p, %s) failed with nsresult %x", aWnd,
+             sMark, uint32_t(hr)));
+  }
+};
+
+/**************************************************************
+ *
+ * SECTION: TaskbarConcealer event callbacks
+ *
+ **************************************************************/
+
+void nsWindow::TaskbarConcealer::OnWindowDestroyed(HWND aWnd) {
+  MOZ_LOG(sTaskbarConcealerLog, LogLevel::Info,
+          ("==> OnWindowDestroyed() for HWND %p", aWnd));
+
+  UpdateAllState(aWnd);
+}
+
+void nsWindow::TaskbarConcealer::OnFocusAcquired(nsWindow* aWin) {
+  // Update state unconditionally.
+  //
+  // This is partially because focus-acquisition only updates the z-order, which
+  // we don't cache and therefore can't notice changes to -- but also because
+  // it's probably a good idea to give the user a natural way to refresh the
+  // current fullscreen-marking state if it's somehow gone bad.
+
+  MOZ_LOG(sTaskbarConcealerLog, LogLevel::Info,
+          ("==> OnFocusAcquired() for HWND %p on HMONITOR %p", aWin->mWnd,
+           ::MonitorFromWindow(aWin->mWnd, MONITOR_DEFAULTTONULL)));
+
+  UpdateAllState();
+}
+
+void nsWindow::TaskbarConcealer::OnFullscreenChanged(nsWindow* aWin,
+                                                     bool enteredFullscreen) {
+  MOZ_LOG(sTaskbarConcealerLog, LogLevel::Info,
+          ("==> OnFullscreenChanged() for HWND %p on HMONITOR %p", aWin->mWnd,
+           ::MonitorFromWindow(aWin->mWnd, MONITOR_DEFAULTTONULL)));
+
+  UpdateAllState();
+}
+
+void nsWindow::TaskbarConcealer::OnWindowPosChanged(nsWindow* aWin) {
+  // Optimization: don't bother updating the state if the window hasn't moved
+  // (including appearances and disappearances).
+  const HWND myHwnd = aWin->mWnd;
+  const HMONITOR oldMonitor = sKnownWindows.Get(myHwnd);  // or nullptr
+  const HMONITOR newMonitor = GetWindowState(myHwnd)
+                                  .map([](auto state) { return state.monitor; })
+                                  .valueOr(nullptr);
+
+  if (oldMonitor == newMonitor) {
+    return;
+  }
+
+  MOZ_LOG(sTaskbarConcealerLog, LogLevel::Info,
+          ("==> OnWindowPosChanged() for HWND %p (HMONITOR %p -> %p)", myHwnd,
+           oldMonitor, newMonitor));
+
+  UpdateAllState();
+}
+
+void nsWindow::TaskbarConcealer::OnAsyncStateUpdateRequest(HWND hwnd) {
+  MOZ_LOG(sTaskbarConcealerLog, LogLevel::Info,
+          ("==> OnAsyncStateUpdateRequest()"));
+
+  // Work around a race condition in explorer.exe.
+  //
+  // When a window is unminimized (and on several other events), the taskbar
+  // receives a notification that it needs to recalculate the current
+  // is-a-fullscreen-window-active-here-state ("rudeness") of each monitor.
+  // Unfortunately, this notification is sent concurrently with the
+  // WM_WINDOWPOSCHANGING message that performs the unminimization.
+  //
+  // Until that message is resolved, the window's position is still "minimized".
+  // If the taskbar processes its notification faster than the window handles
+  // its WM_WINDOWPOSCHANGING message, then the window will appear to the
+  // taskbar to still be minimized, and won't be taken into account for
+  // computing rudeness. This usually presents as a just-unminimized Firefox
+  // fullscreen-window occasionally having the taskbar stuck above it.
+  //
+  // Unfortunately, it's a bit difficult to improve Firefox's speed-of-response
+  // to WM_WINDOWPOSCHANGING messages (we can, and do, execute JavaScript during
+  // these), and even if we could that wouldn't always fix it. We instead adopt
+  // a variant of a strategy by Etienne Duchamps, who has investigated and
+  // documented this issue extensively[0]: we simply send another signal to the
+  // shell to notify it to recalculate the current rudeness state of all
+  // monitors.
+  //
+  // [0]
+  // https://github.com/dechamps/RudeWindowFixer#a-race-condition-activating-a-minimized-window
+  //
+  static UINT const shellHookMsg = ::RegisterWindowMessageW(L"SHELLHOOK");
+  if (shellHookMsg != 0) {
+    // Identifying the particular thread of the particular instance of the
+    // shell associated with our current desktop is probably possible, but
+    // also probably not worth the effort. Just broadcast the message
+    // globally.
+    DWORD info = BSM_APPLICATIONS;
+    ::BroadcastSystemMessage(BSF_POSTMESSAGE | BSF_IGNORECURRENTTASK, &info,
+                             shellHookMsg, HSHELL_WINDOWACTIVATED,
+                             (LPARAM)hwnd);
+  }
+}
+
+void nsWindow::TaskbarConcealer::OnCloakChanged() {
+  MOZ_LOG(sTaskbarConcealerLog, LogLevel::Info, ("==> OnCloakChanged()"));
+
+  UpdateAllState();
+}
diff --git a/widget/windows/nsWindowTaskbarConcealer.h b/widget/windows/nsWindowTaskbarConcealer.h
new file mode 100644
index 0000000000..84567fc857
--- /dev/null
+++ b/widget/windows/nsWindowTaskbarConcealer.h
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WIDGET_WINDOWS_NSWINDOWTASKBARCONCEALER_H_
+#define WIDGET_WINDOWS_NSWINDOWTASKBARCONCEALER_H_
+
+#include "nsWindow.h"
+#include "mozilla/Maybe.h"
+
+/**
+ * nsWindow::TaskbarConcealer
+ *
+ * Fullscreen-state (and, thus, taskbar-occlusion) manager.
+ */
+class nsWindow::TaskbarConcealer {
+ public:
+  // To be called when a window acquires focus. (Note that no action need be
+  // taken when focus is lost.)
+  static void OnFocusAcquired(nsWindow* aWin);
+
+  // To be called during or after a window's destruction. The corresponding
+  // nsWindow pointer is not needed, and will not be acquired or accessed.
+  static void OnWindowDestroyed(HWND aWnd);
+
+  // To be called when the Gecko-fullscreen state of a window changes.
+  static void OnFullscreenChanged(nsWindow* aWin, bool enteredFullscreen);
+
+  // To be called when the position of a window changes. (Performs its own
+  // batching; irrelevant movements will be cheap.)
+  static void OnWindowPosChanged(nsWindow* aWin);
+
+  // To be called when the cloaking state of any window changes. (Expects that
+  // all windows' internal cloaking-state mirror variables are up-to-date.)
+  static void OnCloakChanged();
+
+  // To be called upon receipt of MOZ_WM_FULLSCREEN_STATE_UPDATE.
+  static void OnAsyncStateUpdateRequest(HWND);
+
+ private:
+  static void UpdateAllState(HWND destroyedHwnd = nullptr);
+
+  struct WindowState {
+    HMONITOR monitor;
+    bool isGkFullscreen;
+  };
+  static mozilla::Maybe<WindowState> GetWindowState(HWND);
+
+  static nsTHashMap<HWND, HMONITOR> sKnownWindows;
+};
+
+#endif  // WIDGET_WINDOWS_NSWINDOWTASKBARCONCEALER_H_
diff --git a/widget/windows/nsdefs.h b/widget/windows/nsdefs.h
new file mode 100644
index 0000000000..ebf7892fda
--- /dev/null
+++ b/widget/windows/nsdefs.h
@@ -0,0 +1,58 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef NSDEFS_H
+#define NSDEFS_H
+
+#include <windows.h>
+
+#ifdef _DEBUG
+#  define BREAK_TO_DEBUGGER DebugBreak()
+#else
+#  define BREAK_TO_DEBUGGER
+#endif
+
+#ifdef _DEBUG
+#  define VERIFY(exp)    \
+    if (!(exp)) {        \
+      GetLastError();    \
+      BREAK_TO_DEBUGGER; \
+    }
+#else  // !_DEBUG
+#  define VERIFY(exp) (exp)
+#endif  // !_DEBUG
+
+// inttypes.h-like macro for LONG_PTR/LPARAM formatting.
+#ifdef HAVE_64BIT_BUILD
+#  define PRIdLPTR "lld"
+#  define PRIxLPTR "llx"
+#  define PRIXLPTR "llX"
+#else
+#  define PRIdLPTR "ld"
+#  define PRIxLPTR "lx"
+#  define PRIXLPTR "lX"
+#endif
+
+// Win32 logging modules:
+// nsWindow, nsSound, and nsClipboard
+//
+// Logging can be changed at runtime without recompiling in the General
+// property page of Visual Studio under the "Environment" property.
+//
+// Two variables are of importance to be set:
+// MOZ_LOG and MOZ_LOG_FILE
+//
+// MOZ_LOG:
+// MOZ_LOG=all:5                 (To log everything completely)
+// MOZ_LOG=nsWindow:5,nsSound:5,nsClipboard:5
+//                               (To log windows widget stuff)
+// MOZ_LOG=                      (To turn off logging)
+//
+// MOZ_LOG_FILE:
+// MOZ_LOG_FILE=C:\log.txt       (To a file on disk)
+// MOZ_LOG_FILE=WinDebug         (To the debug window)
+// MOZ_LOG_FILE=                 (To stdout/stderr)
+
+#endif  // NSDEFS_H
diff --git a/widget/windows/res/aliasb.cur b/widget/windows/res/aliasb.cur
new file mode 100644
index 0000000000..8d9ac9478c
--- /dev/null
+++ b/widget/windows/res/aliasb.cur
diff --git a/widget/windows/res/cell.cur b/widget/windows/res/cell.cur
new file mode 100644
index 0000000000..decfbdcac5
--- /dev/null
+++ b/widget/windows/res/cell.cur
diff --git a/widget/windows/res/col_resize.cur b/widget/windows/res/col_resize.cur
new file mode 100644
index 0000000000..8f7f675122
--- /dev/null
+++ b/widget/windows/res/col_resize.cur
diff --git a/widget/windows/res/copy.cur b/widget/windows/res/copy.cur
new file mode 100644
index 0000000000..87f1519cd1
--- /dev/null
+++ b/widget/windows/res/copy.cur
diff --git a/widget/windows/res/grab.cur b/widget/windows/res/grab.cur
new file mode 100644
index 0000000000..db7ad5aed3
--- /dev/null
+++ b/widget/windows/res/grab.cur
diff --git a/widget/windows/res/grabbing.cur b/widget/windows/res/grabbing.cur
new file mode 100644
index 0000000000..e0dfd04e4d
--- /dev/null
+++ b/widget/windows/res/grabbing.cur
diff --git a/widget/windows/res/none.cur b/widget/windows/res/none.cur
new file mode 100644
index 0000000000..2114dfaee3
--- /dev/null
+++ b/widget/windows/res/none.cur
diff --git a/widget/windows/res/row_resize.cur b/widget/windows/res/row_resize.cur
new file mode 100644
index 0000000000..a7369d32d1
--- /dev/null
+++ b/widget/windows/res/row_resize.cur
diff --git a/widget/windows/res/select.cur b/widget/windows/res/select.cur
new file mode 100644
index 0000000000..5a88b3707e
--- /dev/null
+++ b/widget/windows/res/select.cur
diff --git a/widget/windows/res/vertical_text.cur b/widget/windows/res/vertical_text.cur
new file mode 100644
index 0000000000..3de04ebec3
--- /dev/null
+++ b/widget/windows/res/vertical_text.cur
diff --git a/widget/windows/res/zoom_in.cur b/widget/windows/res/zoom_in.cur
new file mode 100644
index 0000000000..b594d79271
--- /dev/null
+++ b/widget/windows/res/zoom_in.cur
diff --git a/widget/windows/res/zoom_out.cur b/widget/windows/res/zoom_out.cur
new file mode 100644
index 0000000000..7e495fbaa4
--- /dev/null
+++ b/widget/windows/res/zoom_out.cur
diff --git a/widget/windows/resource.h b/widget/windows/resource.h
new file mode 100644
index 0000000000..a367e9f3e9
--- /dev/null
+++ b/widget/windows/resource.h
@@ -0,0 +1,16 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#define IDC_GRAB 4101
+#define IDC_GRABBING 4102
+#define IDC_CELL 4103
+#define IDC_COPY 4104
+#define IDC_ALIAS 4105
+#define IDC_ZOOMIN 4106
+#define IDC_ZOOMOUT 4107
+#define IDC_COLRESIZE 4108
+#define IDC_ROWRESIZE 4109
+#define IDC_VERTICALTEXT 4110
+#define IDC_DUMMY_CE_MENUBAR 4111
+#define IDC_NONE 4112
diff --git a/widget/windows/tests/TestUriValidation.cpp b/widget/windows/tests/TestUriValidation.cpp
new file mode 100644
index 0000000000..d8a0ca09ce
--- /dev/null
+++ b/widget/windows/tests/TestUriValidation.cpp
@@ -0,0 +1,135 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#define MOZ_USE_LAUNCHER_ERROR
+
+#define UNICODE
+#include "mozilla/UrlmonHeaderOnlyUtils.h"
+#include "TestUrisToValidate.h"
+
+#include <urlmon.h>
+
+using namespace mozilla;
+
+static LauncherResult<_bstr_t> ShellValidateUri(const wchar_t* aUri) {
+  LauncherResult<UniqueAbsolutePidl> pidlResult = ShellParseDisplayName(aUri);
+  if (pidlResult.isErr()) {
+    return pidlResult.propagateErr();
+  }
+  UniqueAbsolutePidl pidl = pidlResult.unwrap();
+
+  // |pidl| is an absolute path. IShellFolder::GetDisplayNameOf requires a
+  // valid child ID, so the first thing we need to resolve is the IShellFolder
+  // for |pidl|'s parent, as well as the childId that represents |pidl|.
+  // Fortunately SHBindToParent does exactly that!
+  PCUITEMID_CHILD childId = nullptr;
+  RefPtr<IShellFolder> parentFolder;
+  HRESULT hr = SHBindToParent(pidl.get(), IID_IShellFolder,
+                              getter_AddRefs(parentFolder), &childId);
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  // Now we retrieve the display name of |childId|, telling the shell that we
+  // plan to have the string parsed.
+  STRRET strret;
+  hr = parentFolder->GetDisplayNameOf(childId, SHGDN_FORPARSING, &strret);
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  // StrRetToBSTR automatically takes care of freeing any dynamically
+  // allocated memory in |strret|.
+  _bstr_t bstrUri;
+  hr = StrRetToBSTR(&strret, nullptr, bstrUri.GetAddress());
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  return bstrUri;
+}
+
+static LauncherResult<_bstr_t> GetFragment(const wchar_t* aUri) {
+  constexpr DWORD flags =
+      Uri_CREATE_NO_DECODE_EXTRA_INFO | Uri_CREATE_CANONICALIZE |
+      Uri_CREATE_CRACK_UNKNOWN_SCHEMES | Uri_CREATE_PRE_PROCESS_HTML_URI |
+      Uri_CREATE_IE_SETTINGS;
+  RefPtr<IUri> uri;
+  HRESULT hr = CreateUri(aUri, flags, 0, getter_AddRefs(uri));
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+
+  _bstr_t bstrFragment;
+  hr = uri->GetFragment(bstrFragment.GetAddress());
+  if (FAILED(hr)) {
+    return LAUNCHER_ERROR_FROM_HRESULT(hr);
+  }
+  return bstrFragment;
+}
+
+static bool RunSingleTest(const wchar_t* aUri) {
+  LauncherResult<_bstr_t> uriOld = ShellValidateUri(aUri),
+                          uriNew = UrlmonValidateUri(aUri);
+  if (uriOld.isErr() != uriNew.isErr()) {
+    printf("TEST-FAILED | UriValidation | Validation result mismatch on %S\n",
+           aUri);
+    return false;
+  }
+
+  if (uriOld.isErr()) {
+    if (uriOld.unwrapErr().mError != uriNew.unwrapErr().mError) {
+      printf("TEST-FAILED | UriValidation | Error code mismatch on %S\n", aUri);
+      return false;
+    }
+    return true;
+  }
+
+  LauncherResult<_bstr_t> bstrFragment = GetFragment(aUri);
+  if (bstrFragment.isErr()) {
+    printf("TEST-FAILED | UriValidation | Failed to get a fragment from %S\n",
+           aUri);
+    return false;
+  }
+
+  // We validate a uri with two logics: the current one UrlmonValidateUri and
+  // the older one ShellValidateUri, to make sure the same validation result.
+  // We introduced UrlmonValidateUri because ShellValidateUri drops a fragment
+  // in a uri due to the design of Windows.  To bypass the fragment issue, we
+  // extract a fragment and appends it into the validated string, and compare.
+  _bstr_t bstrUriOldCorrected = uriOld.unwrap() + bstrFragment.unwrap();
+  const _bstr_t& bstrUriNew = uriNew.unwrap();
+  if (bstrUriOldCorrected != bstrUriNew) {
+    printf("TEST-FAILED | UriValidation | %S %S %S\n", aUri,
+           static_cast<const wchar_t*>(bstrUriOldCorrected),
+           static_cast<const wchar_t*>(bstrUriNew));
+    return false;
+  }
+
+  return true;
+}
+
+int wmain(int argc, wchar_t* argv[]) {
+  HRESULT hr = CoInitialize(nullptr);
+  if (FAILED(hr)) {
+    return 1;
+  }
+
+  bool isOk = true;
+
+  if (argc == 2) {
+    isOk = RunSingleTest(argv[1]);
+  } else {
+    for (const wchar_t*& testUri : kTestUris) {
+      if (!RunSingleTest(testUri)) {
+        isOk = false;
+      }
+    }
+  }
+
+  CoUninitialize();
+  return isOk ? 0 : 1;
+}
diff --git a/widget/windows/tests/TestUrisToValidate.h b/widget/windows/tests/TestUrisToValidate.h
new file mode 100644
index 0000000000..cb00366d1e
--- /dev/null
+++ b/widget/windows/tests/TestUrisToValidate.h
@@ -0,0 +1,471 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

+/* vim: set ts=8 sts=2 et sw=2 tw=80: */

+/* This Source Code Form is subject to the terms of the Mozilla Public

+ * License, v. 2.0. If a copy of the MPL was not distributed with this

+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

+

+#ifndef mozilla_TestUrisToValidate_h

+#define mozilla_TestUrisToValidate_h

+

+const wchar_t* kTestUris[] = {

+    L"callto:%.txt",

+    L"callto:%00.txt",

+    L"callto:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"fdaction:%.txt",

+    L"fdaction:%00.txt",

+    L"fdaction:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"feed:%.txt",

+    L"feed:%00.txt",

+    L"feed:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"feeds:%.txt",

+    L"feeds:%00.txt",

+    L"feeds:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"file:///%.txt",

+    L"file:///%00.txt",

+    L"file:///%41%2D%31%5Ftest%22ing?%41%31%00.txt",

+    L"firefox.url:%.txt",

+    L"firefox.url:%00.txt",

+    L"firefox.url:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"firefoxurl:%.txt",

+    L"firefoxurl:%00.txt",

+    L"firefoxurl:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"ftp:%.txt",

+    L"ftp:%00.txt",

+    L"ftp:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"gopher:%.txt",

+    L"gopher:%00.txt",

+    L"gopher:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"gtalk:%.txt",

+    L"gtalk:%00.txt",

+    L"gtalk:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"HTTP:%.txt",

+    L"HTTP:%00.txt",

+    L"HTTP:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"http:%.txt",

+    L"http:%00.txt",

+    L"http:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"https://bug389580.bmoattachments.org/%.txt",

+    L"https://bug389580.bmoattachments.org/%00.txt",

+    L"https://bug389580.bmoattachments.org/"

+    L"%41%2D%31%5Ftest%22ing?%41%31%00.txt",

+    L"ie.ftp:%.txt",

+    L"ie.ftp:%00.txt",

+    L"ie.ftp:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"ie.http:%.txt",

+    L"ie.http:%00.txt",

+    L"ie.http:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"ie.https:%.txt",

+    L"ie.https:%00.txt",

+    L"ie.https:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"irc:%.txt",

+    L"irc:%00.txt",

+    L"irc:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"ircs:%.txt",

+    L"ircs:%00.txt",

+    L"ircs:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"itms:%.txt",

+    L"itms:%00.txt",

+    L"itms:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"itmss:%.txt",

+    L"itmss:%00.txt",

+    L"itmss:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"itpc:%.txt",

+    L"itpc:%00.txt",

+    L"itpc:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"itunes.assocprotocol.itms:%.txt",

+    L"itunes.assocprotocol.itms:%00.txt",

+    L"itunes.assocprotocol.itms:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"itunes.assocprotocol.itmss:%.txt",

+    L"itunes.assocprotocol.itmss:%00.txt",

+    L"itunes.assocprotocol.itmss:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"itunes.assocprotocol.itpc:%.txt",

+    L"itunes.assocprotocol.itpc:%00.txt",

+    L"itunes.assocprotocol.itpc:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"ldap:%.txt",

+    L"ldap:%00.txt",

+    L"ldap:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"mailto:%.txt",

+    L"mailto:%00.txt",

+    L"mailto:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"mms:%.txt",

+    L"mms:%00.txt",

+    L"mms:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"mmst:%.txt",

+    L"mmst:%00.txt",

+    L"mmst:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"mmst:%.txt",

+    L"mmst:%00.txt",

+    L"mmst:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"mmsu:%.txt",

+    L"mmsu:%00.txt",

+    L"mmsu:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"mmsu:%.txt",

+    L"mmsu:%00.txt",

+    L"mmsu:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"https://bug389580.bmoattachments.org/"

+    L"Mozilla%20Thunderbird.Url.Mailto:%.txt",

+    L"https://bug389580.bmoattachments.org/"

+    L"Mozilla%20Thunderbird.Url.Mailto:%00.txt",

+    L"https://bug389580.bmoattachments.org/"

+    L"Mozilla%20Thunderbird.Url.Mailto:%41%2D%31%5Ftest%22ing?%41%31%00.txt",

+    L"navigatorurl:%.txt",

+    L"navigatorurl:%00.txt",

+    L"navigatorurl:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"news:%.txt",

+    L"news:%00.txt",

+    L"news:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"nntp:%.txt",

+    L"nntp:%00.txt",

+    L"nntp:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"oms:%.txt",

+    L"oms:%00.txt",

+    L"oms:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"outlook:%.txt",

+    L"outlook:%00.txt",

+    L"outlook:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"outlook.url.feed:%.txt",

+    L"outlook.url.feed:%00.txt",

+    L"outlook.url.feed:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"outlook.url.mailto:%.txt",

+    L"outlook.url.mailto:%00.txt",

+    L"outlook.url.mailto:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"outlook.url.webcal:%.txt",

+    L"outlook.url.webcal:%00.txt",

+    L"outlook.url.webcal:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"outlookfeed:%.txt",

+    L"outlookfeed:%00.txt",

+    L"outlookfeed:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"outlookfeeds:%.txt",

+    L"outlookfeeds:%00.txt",

+    L"outlookfeeds:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"pnm:%.txt",

+    L"pnm:%00.txt",

+    L"pnm:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"prls.intappfile.ftp:%.txt",

+    L"prls.intappfile.ftp:%00.txt",

+    L"prls.intappfile.ftp:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"prls.intappfile.http:%.txt",

+    L"prls.intappfile.http:%00.txt",

+    L"prls.intappfile.http:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"prls.intappfile.https:%.txt",

+    L"prls.intappfile.https:%00.txt",

+    L"prls.intappfile.https:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"prls.intappfile.mailto:%.txt",

+    L"prls.intappfile.mailto:%00.txt",

+    L"prls.intappfile.mailto:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"rlogin:%.txt",

+    L"rlogin:%00.txt",

+    L"rlogin:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"rtsp:%.txt",

+    L"rtsp:%00.txt",

+    L"rtsp:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"scp:%.txt",

+    L"scp:%00.txt",

+    L"scp:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"sftp:%.txt",

+    L"sftp:%00.txt",

+    L"sftp:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"sip:%.txt",

+    L"sip:%00.txt",

+    L"sip:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"skype:%.txt",

+    L"skype:%00.txt",

+    L"skype:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"snews:%.txt",

+    L"snews:%00.txt",

+    L"snews:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"telnet:%.txt",

+    L"telnet:%00.txt",

+    L"telnet:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"thunderbird.url.mailto:%.txt",

+    L"thunderbird.url.mailto:%00.txt",

+    L"thunderbird.url.mailto:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"thunderbird.url.news:%.txt",

+    L"thunderbird.url.news:%00.txt",

+    L"thunderbird.url.news:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"tn3270:%.txt",

+    L"tn3270:%00.txt",

+    L"tn3270:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"tscrec4:%.txt",

+    L"tscrec4:%00.txt",

+    L"tscrec4:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"webcal:%.txt",

+    L"webcal:%00.txt",

+    L"webcal:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"webcal:%.txt",

+    L"webcal:%00.txt",

+    L"webcal:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"webcals:%.txt",

+    L"webcals:%00.txt",

+    L"webcals:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"windowscalendar.urlwebcal.1:%.txt",

+    L"windowscalendar.urlwebcal.1:%00.txt",

+    L"windowscalendar.urlwebcal.1:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"windowsmail.url.mailto:%.txt",

+    L"windowsmail.url.mailto:%00.txt",

+    L"windowsmail.url.mailto:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"windowsmail.url.news:%.txt",

+    L"windowsmail.url.news:%00.txt",

+    L"windowsmail.url.news:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"windowsmail.url.nntp:%.txt",

+    L"windowsmail.url.nntp:%00.txt",

+    L"windowsmail.url.nntp:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"windowsmail.url.snews:%.txt",

+    L"windowsmail.url.snews:%00.txt",

+    L"windowsmail.url.snews:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"wmp11.assocprotocol.mms:%.txt",

+    L"wmp11.assocprotocol.mms:%00.txt",

+    L"wmp11.assocprotocol.mms:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"wpc:%.txt",

+    L"wpc:%00.txt",

+    L"wpc:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"ymsgr:%.txt",

+    L"ymsgr:%00.txt",

+    L"ymsgr:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"acrobat:%.txt",

+    L"acrobat:%00.txt",

+    L"acrobat:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"acsui:%.txt",

+    L"acsui:%00.txt",

+    L"acsui:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"aim:%.txt",

+    L"aim:%00.txt",

+    L"aim:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"aim:%.txt",

+    L"aim:%00.txt",

+    L"aim:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"allc8.commands.2:%.txt",

+    L"allc8.commands.2:%00.txt",

+    L"allc8.commands.2:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"allholdem.commands.2:%.txt",

+    L"allholdem.commands.2:%00.txt",

+    L"allholdem.commands.2:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"allpoker.commands.2:%.txt",

+    L"allpoker.commands.2:%00.txt",

+    L"allpoker.commands.2:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"aolautofix:%.txt",

+    L"aolautofix:%00.txt",

+    L"aolautofix:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"aolds:%.txt",

+    L"aolds:%00.txt",

+    L"aolds:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"bc:%.txt",

+    L"bc:%00.txt",

+    L"bc:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"bctp:%.txt",

+    L"bctp:%00.txt",

+    L"bctp:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"bittorrent:%.txt",

+    L"bittorrent:%00.txt",

+    L"bittorrent:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"camfrog:%.txt",

+    L"camfrog:%00.txt",

+    L"camfrog:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"csi:%.txt",

+    L"csi:%00.txt",

+    L"csi:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"cvs:%.txt",

+    L"cvs:%00.txt",

+    L"cvs:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"daap:%.txt",

+    L"daap:%00.txt",

+    L"daap:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"ed2k:%.txt",

+    L"ed2k:%00.txt",

+    L"ed2k:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"explorer.assocprotocol.search-ms:%.txt",

+    L"explorer.assocprotocol.search-ms:%00.txt",

+    L"explorer.assocprotocol.search-ms:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"gizmoproject:%.txt",

+    L"gizmoproject:%00.txt",

+    L"gizmoproject:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"gnet:%.txt",

+    L"gnet:%00.txt",

+    L"gnet:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"gnutella:%.txt",

+    L"gnutella:%00.txt",

+    L"gnutella:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"gsarcade:%.txt",

+    L"gsarcade:%00.txt",

+    L"gsarcade:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"hcp:%.txt",

+    L"hcp:%00.txt",

+    L"hcp:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"icquser:%.txt",

+    L"icquser:%00.txt",

+    L"icquser:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"icy:%.txt",

+    L"icy:%00.txt",

+    L"icy:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"imesync:%.txt",

+    L"imesync:%00.txt",

+    L"imesync:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"itunes.assocprotocol.daap:%.txt",

+    L"itunes.assocprotocol.daap:%00.txt",

+    L"itunes.assocprotocol.daap:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"itunes.assocprotocol.pcast:%.txt",

+    L"itunes.assocprotocol.pcast:%00.txt",

+    L"itunes.assocprotocol.pcast:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"joost:%.txt",

+    L"joost:%00.txt",

+    L"joost:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"m4macdrive:%.txt",

+    L"m4macdrive:%00.txt",

+    L"m4macdrive:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"magnet:%.txt",

+    L"magnet:%00.txt",

+    L"magnet:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"mapi:%.txt",

+    L"mapi:%00.txt",

+    L"mapi:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"mc12:%.txt",

+    L"mc12:%00.txt",

+    L"mc12:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"mediajukebox:%.txt",

+    L"mediajukebox:%00.txt",

+    L"mediajukebox:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"morpheus:%.txt",

+    L"morpheus:%00.txt",

+    L"morpheus:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"mp2p:%.txt",

+    L"mp2p:%00.txt",

+    L"mp2p:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"mpodcast:%.txt",

+    L"mpodcast:%00.txt",

+    L"mpodcast:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"msbd:%.txt",

+    L"msbd:%00.txt",

+    L"msbd:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"msbd:%.txt",

+    L"msbd:%00.txt",

+    L"msbd:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"msdigitallocker:%.txt",

+    L"msdigitallocker:%00.txt",

+    L"msdigitallocker:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"outlook.url.stssync:%.txt",

+    L"outlook.url.stssync:%00.txt",

+    L"outlook.url.stssync:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"p2p:%.txt",

+    L"p2p:%00.txt",

+    L"p2p:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"pando:%.txt",

+    L"pando:%00.txt",

+    L"pando:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"pcast:%.txt",

+    L"pcast:%00.txt",

+    L"pcast:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"picasa:%.txt",

+    L"picasa:%00.txt",

+    L"picasa:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"plaxo:%.txt",

+    L"plaxo:%00.txt",

+    L"plaxo:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"play:%.txt",

+    L"play:%00.txt",

+    L"play:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"podcast:%.txt",

+    L"podcast:%00.txt",

+    L"podcast:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"ppmate:%.txt",

+    L"ppmate:%00.txt",

+    L"ppmate:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"ppmates:%.txt",

+    L"ppmates:%00.txt",

+    L"ppmates:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"ppstream:%.txt",

+    L"ppstream:%00.txt",

+    L"ppstream:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"quicktime:%.txt",

+    L"quicktime:%00.txt",

+    L"quicktime:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"realplayer.autoplay.6:%.txt",

+    L"realplayer.autoplay.6:%00.txt",

+    L"realplayer.autoplay.6:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"realplayer.cdburn.6:%.txt",

+    L"realplayer.cdburn.6:%00.txt",

+    L"realplayer.cdburn.6:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"rhap:%.txt",

+    L"rhap:%00.txt",

+    L"rhap:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"sc:%.txt",

+    L"sc:%00.txt",

+    L"sc:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"search-ms:%.txt",

+    L"search-ms:%00.txt",

+    L"search-ms:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"shareaza:%.txt",

+    L"shareaza:%00.txt",

+    L"shareaza:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"shell:%.txt",

+    L"shell:%00.txt",

+    L"shell:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"shout:%.txt",

+    L"shout:%00.txt",

+    L"shout:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"sig2dat:%.txt",

+    L"sig2dat:%00.txt",

+    L"sig2dat:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"sop:%.txt",

+    L"sop:%00.txt",

+    L"sop:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"steam:%.txt",

+    L"steam:%00.txt",

+    L"steam:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"stssync:%.txt",

+    L"stssync:%00.txt",

+    L"stssync:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"svn:%.txt",

+    L"svn:%00.txt",

+    L"svn:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"svn+ssh:%.txt",

+    L"svn+ssh:%00.txt",

+    L"svn+ssh:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"synacast:%.txt",

+    L"synacast:%00.txt",

+    L"synacast:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"torrent:%.txt",

+    L"torrent:%00.txt",

+    L"torrent:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"tsvn:%.txt",

+    L"tsvn:%00.txt",

+    L"tsvn:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"tvants:%.txt",

+    L"tvants:%00.txt",

+    L"tvants:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"tvu:%.txt",

+    L"tvu:%00.txt",

+    L"tvu:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"unsv:%.txt",

+    L"unsv:%00.txt",

+    L"unsv:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"uvox:%.txt",

+    L"uvox:%00.txt",

+    L"uvox:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"ventrilo:%.txt",

+    L"ventrilo:%00.txt",

+    L"ventrilo:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"vs:%.txt",

+    L"vs:%00.txt",

+    L"vs:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"zune:%.txt",

+    L"zune:%00.txt",

+    L"zune:%41%2D%31%5Ftest&quot;ing?%41%31%00.txt",

+    L"https://example.com/?a=123&b=456",

+    L"https://example.com/#123?a=123&b=456",

+    L"https://example.com/?#123a=123&b=456",

+    L"https://example.com/?a=123&b=456#123",

+    L"mailto:%41%42%23%31",

+    L"mailto:%41%42%23%31#fragment",

+    L"news:%41%42%23%31",

+    L"news:%41%42%23%31#fragment",

+    L"microsoft-edge:%41%42%23%31",

+    L"microsoft-edge:%41%42%23%31#fragment",

+    L"microsoft-edge:%41%42%23%31#fragment#",

+    L"microsoft-edge:%41%42%23%31####",

+    L"something-unknown:",

+    L"something-unknown:x=123",

+    L"something-unknown:?=123",

+    L"something-unknown:#code=0123456789%200123456789&x=01234567890123456789",

+};

+

+#endif  // mozilla_TestUrisToValidate_h

diff --git a/widget/windows/tests/gtest/TestJumpListBuilder.cpp b/widget/windows/tests/gtest/TestJumpListBuilder.cpp
new file mode 100644
index 0000000000..5494c42d37
--- /dev/null
+++ b/widget/windows/tests/gtest/TestJumpListBuilder.cpp
@@ -0,0 +1,823 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <objectarray.h>
+#include <shobjidl.h>
+#include <windows.h>
+#include <string.h>
+#include <propvarutil.h>
+#include <propkey.h>
+
+#ifdef __MINGW32__
+// MinGW-w64 headers are missing PropVariantToString.
+#  include <propsys.h>
+PSSTDAPI PropVariantToString(REFPROPVARIANT propvar, PWSTR psz, UINT cch);
+#endif
+
+#include "gtest/gtest.h"
+#include "gmock/gmock.h"
+
+#include "mozilla/dom/BindingDeclarations.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/PromiseNativeHandler.h"
+#include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/dom/ToJSValue.h"
+#include "mozilla/dom/WindowsJumpListShortcutDescriptionBinding.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "JumpListBuilder.h"
+
+using namespace mozilla;
+using namespace testing;
+using mozilla::dom::AutoJSAPI;
+using mozilla::dom::Promise;
+using mozilla::dom::PromiseNativeHandler;
+using mozilla::dom::ToJSValue;
+using mozilla::dom::WindowsJumpListShortcutDescription;
+using mozilla::widget::JumpListBackend;
+using mozilla::widget::JumpListBuilder;
+
+/**
+ * GMock matcher that ensures that two LPCWSTRs match.
+ */
+MATCHER_P(LPCWSTREq, value, "The equivalent of StrEq for LPCWSTRs") {
+  return (wcscmp(arg, value)) == 0;
+}
+
+/**
+ * GMock matcher that ensures that a IObjectArray* contains nsIShellLinkW's
+ * that match an equivalent set of nsTArray<WindowsJumpListShortcutDescriptions>
+ */
+MATCHER_P(ShellLinksEq, descs,
+          "Comparing generated IShellLinkW with "
+          "WindowsJumpListShortcutDescription definitions") {
+  uint32_t count = 0;
+  HRESULT hr = arg->GetCount(&count);
+  if (FAILED(hr) || count != descs->Length()) {
+    return false;
+  }
+
+  for (uint32_t i = 0; i < descs->Length(); ++i) {
+    RefPtr<IShellLinkW> link;
+    if (FAILED(arg->GetAt(i, IID_IShellLinkW,
+                          static_cast<void**>(getter_AddRefs(link))))) {
+      return false;
+    }
+
+    if (!link) {
+      return false;
+    }
+
+    const WindowsJumpListShortcutDescription& desc = descs->ElementAt(i);
+
+    // We'll now compare each member of the WindowsJumpListShortcutDescription
+    // with what is stored in the IShellLink.
+
+    // WindowsJumpListShortcutDescription.title
+    IPropertyStore* propStore = nullptr;
+    hr = link->QueryInterface(IID_IPropertyStore, (LPVOID*)&propStore);
+    if (FAILED(hr)) {
+      return false;
+    }
+
+    PROPVARIANT pv;
+    hr = propStore->GetValue(PKEY_Title, &pv);
+    if (FAILED(hr)) {
+      return false;
+    }
+
+    wchar_t title[PKEYSTR_MAX];
+    hr = PropVariantToString(pv, title, PKEYSTR_MAX);
+    if (FAILED(hr)) {
+      return false;
+    }
+
+    if (!desc.mTitle.Equals(title)) {
+      return false;
+    }
+
+    // WindowsJumpListShortcutDescription.path
+    wchar_t pathBuf[MAX_PATH];
+    hr = link->GetPath(pathBuf, MAX_PATH, nullptr, SLGP_SHORTPATH);
+    if (FAILED(hr)) {
+      return false;
+    }
+
+    if (!desc.mPath.Equals(pathBuf)) {
+      return false;
+    }
+
+    // WindowsJumpListShortcutDescription.arguments (optional)
+    wchar_t argsBuf[MAX_PATH];
+    hr = link->GetArguments(argsBuf, MAX_PATH);
+    if (FAILED(hr)) {
+      return false;
+    }
+
+    if (desc.mArguments.WasPassed()) {
+      if (!desc.mArguments.Value().Equals(argsBuf)) {
+        return false;
+      }
+    } else {
+      // Otherwise, the arguments should be empty.
+      if (wcsnlen(argsBuf, MAX_PATH) != 0) {
+        return false;
+      }
+    }
+
+    // WindowsJumpListShortcutDescription.description
+    wchar_t descBuf[MAX_PATH];
+    hr = link->GetDescription(descBuf, MAX_PATH);
+    if (FAILED(hr)) {
+      return false;
+    }
+
+    if (!desc.mDescription.Equals(descBuf)) {
+      return false;
+    }
+
+    // WindowsJumpListShortcutDescription.iconPath and
+    // WindowsJumpListShortcutDescription.fallbackIconIndex
+    int iconIdx = 0;
+    wchar_t iconPathBuf[MAX_PATH];
+    hr = link->GetIconLocation(iconPathBuf, MAX_PATH, &iconIdx);
+    if (FAILED(hr)) {
+      return false;
+    }
+
+    if (desc.mIconPath.WasPassed() && !desc.mIconPath.Value().IsEmpty()) {
+      // If the WindowsJumpListShortcutDescription supplied an iconPath,
+      // then it should match iconPathBuf and have an icon index of 0.
+      if (!desc.mIconPath.Value().Equals(iconPathBuf) || iconIdx != 0) {
+        return false;
+      }
+    } else {
+      // Otherwise, the iconPathBuf should equal the
+      // WindowsJumpListShortcutDescription path, and the iconIdx should match
+      // the fallbackIconIndex.
+      if (!desc.mPath.Equals(iconPathBuf) ||
+          desc.mFallbackIconIndex != iconIdx) {
+        return false;
+      }
+    }
+  }
+
+  return true;
+}
+
+/**
+ * This is a helper class that allows our tests to wait for a native DOM Promise
+ * to resolve, and get the JS::Value that the Promise resolves with. This is
+ * expected to run on the main thread.
+ */
+class WaitForResolver : public PromiseNativeHandler {
+ public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WaitForResolver, override)
+
+  NS_IMETHODIMP QueryInterface(REFNSIID aIID, void** aInstancePtr) override {
+    nsresult rv = NS_ERROR_UNEXPECTED;
+    NS_INTERFACE_TABLE0(WaitForResolver)
+
+    return rv;
+  }
+
+  WaitForResolver() : mIsDone(false) {}
+
+  void ResolvedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                        ErrorResult& aError) override {
+    mResult = aValue;
+    mIsDone = true;
+  }
+
+  void RejectedCallback(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                        ErrorResult& aError) override {
+    ASSERT_TRUE(false);  // Should never reach here.
+  }
+
+  /**
+   * Spins a nested event loop and blocks until the Promise has resolved.
+   */
+  void SpinUntilResolved() {
+    SpinEventLoopUntil("WaitForResolver::SpinUntilResolved"_ns,
+                       [&]() { return mIsDone; });
+  }
+
+  /**
+   * Spins a nested event loop and blocks until the Promise has resolved,
+   * after which the JS::Value that the Promise resolves with is returned via
+   * the aRetval outparam.
+   *
+   * @param {JS::MutableHandle<JS::Value>} aRetval
+   *   The outparam for the JS::Value that the Promise resolves with.
+   */
+  void SpinUntilResolvedWithResult(JS::MutableHandle<JS::Value> aRetval) {
+    SpinEventLoopUntil("WaitForResolver::SpinUntilResolved"_ns,
+                       [&]() { return mIsDone; });
+    aRetval.set(mResult);
+  }
+
+ private:
+  virtual ~WaitForResolver() = default;
+
+  JS::Heap<JS::Value> mResult;
+  bool mIsDone;
+};
+
+/**
+ * An implementation of JumpListBackend that is instrumented using the GMock
+ * framework to record calls. Unlike the NativeJumpListBackend, this backend
+ * is expected to be instantiated on the main thread and passed as an argument
+ * to the JumpListBuilder's worker thread. Testers should wait for the methods
+ * that call these functions to resolve their Promises before checking the
+ * recorded values.
+ */
+class TestingJumpListBackend : public JumpListBackend {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(JumpListBackend, override)
+
+  TestingJumpListBackend() : mMonitor("TestingJumpListBackend::mMonitor") {}
+
+  virtual bool IsAvailable() override { return true; }
+
+  MOCK_METHOD(HRESULT, SetAppID, (LPCWSTR));
+  MOCK_METHOD(HRESULT, BeginList, (UINT*, REFIID, void**));
+  MOCK_METHOD(HRESULT, AddUserTasks, (IObjectArray*));
+  MOCK_METHOD(HRESULT, AppendCategory, (LPCWSTR, IObjectArray*));
+  MOCK_METHOD(HRESULT, CommitList, ());
+  MOCK_METHOD(HRESULT, AbortList, ());
+  MOCK_METHOD(HRESULT, DeleteList, (LPCWSTR));
+
+  virtual HRESULT AppendKnownCategory(KNOWNDESTCATEGORY category) override {
+    return 0;
+  }
+
+  // In one case (construction), an operation occurs off of the main thread that
+  // we must wait for without an associated Promise.
+  Monitor& GetMonitor() { return mMonitor; }
+
+ protected:
+  virtual ~TestingJumpListBackend() override{};
+
+ private:
+  Monitor mMonitor;
+};
+
+/**
+ * A helper function that creates some fake WindowsJumpListShortcutDescription
+ * objects as well as JS::Value representations of those objects. These are
+ * returned to the caller through outparams.
+ *
+ * @param {JSContext*} aCx
+ *   The current JSContext in the execution environment.
+ * @param {uint32_t} howMany
+ *   The number of WindowsJumpListShortcutDescriptions to generate.
+ * @param {boolean} longDescription
+ *   True if the description should be greater than MAX_PATH (260 characters).
+ * @param {nsTArray<WindowsJumpListShortcutDescription>&} aArray
+ *   The outparam for the array of generated
+ * WindowsJumpListShortcutDescriptions.
+ * @param {nsTArray<JS::Value>&} aJSValArray
+ *   The outparam for the array of JS::Value's representing the generated
+ *   WindowsJumpListShortcutDescriptions.
+ */
+void GenerateWindowsJumpListShortcutDescriptions(
+    JSContext* aCx, uint32_t howMany, bool longDescription,
+    nsTArray<WindowsJumpListShortcutDescription>& aArray,
+    nsTArray<JS::Value>& aJSValArray) {
+  for (uint32_t i = 0; i < howMany; ++i) {
+    WindowsJumpListShortcutDescription desc;
+    nsAutoString title(u"Test Task #");
+    title.AppendInt(i);
+    desc.mTitle = title;
+
+    nsAutoString path(u"C:\\Some\\Test\\Path.exe");
+    desc.mPath = path;
+    nsAutoString description;
+
+    if (longDescription) {
+      description.AppendPrintf(
+          "For item #%i, this is a very very very very VERY VERY very very "
+          "very very very very very very very very very very VERY VERY very "
+          "very very very very very very very very very very very VERY VERY "
+          "very very very very very very very very very very very very VERY "
+          "VERY very very very very very very very very very very very very "
+          "VERY VERY very very very very very very very very very very very "
+          "very VERY VERY very very very very very very very very long test "
+          "description for an item",
+          i);
+    } else {
+      description.AppendPrintf("This is a test description for an item #%i", i);
+    }
+
+    desc.mDescription = description;
+    desc.mFallbackIconIndex = 0;
+
+    if (!(i % 2)) {
+      nsAutoString arguments(u"-arg1 -arg2 -arg3");
+      desc.mArguments.Construct(arguments);
+      nsAutoString iconPath(u"C:\\Some\\icon.png");
+      desc.mIconPath.Construct(iconPath);
+    }
+
+    aArray.AppendElement(desc);
+    JS::Rooted<JS::Value> descJSValue(aCx);
+    ASSERT_TRUE(ToJSValue(aCx, desc, &descJSValue));
+    aJSValArray.AppendElement(std::move(descJSValue));
+  }
+}
+
+/**
+ * Tests construction and that the application ID is properly passed to the
+ * backend.
+ */
+TEST(JumpListBuilder, Construction)
+{
+  RefPtr<StrictMock<TestingJumpListBackend>> testBackend =
+      new StrictMock<TestingJumpListBackend>();
+  ASSERT_TRUE(testBackend);
+
+  nsAutoString aumid(u"TestApplicationID");
+  LPCWSTR passedID = aumid.get();
+  // Construction of our class (or any class of that matter) does not return a
+  // Promise that we can wait on to ensure that the background thread got the
+  // right information. We therefore use a monitor on the testing backend as
+  // well as an EXPECT_CALL to block execution of the test until the background
+  // work has completed.
+  Monitor& mon = testBackend->GetMonitor();
+  MonitorAutoLock lock(mon);
+  EXPECT_CALL(*testBackend, SetAppID(LPCWSTREq(passedID))).WillOnce([&mon] {
+    MonitorAutoLock lock(mon);
+    mon.Notify();
+    return S_OK;
+  });
+
+  nsCOMPtr<nsIJumpListBuilder> builder =
+      new JumpListBuilder(aumid, testBackend);
+  ASSERT_TRUE(builder);
+
+  // This is the amount of time that we will wait for the background thread to
+  // respond before considering it a timeout failure.
+  const int kWaitTimeoutMs = 5000;
+
+  ASSERT_TRUE(mon.Wait(TimeDuration::FromMilliseconds(kWaitTimeoutMs)) !=
+              CVStatus::Timeout);
+}
+
+/**
+ * Tests calling CheckForRemovals and receiving a series of removed jump list
+ * entries. Calling CheckForRemovals should call the following methods on the
+ * backend, in order:
+ *
+ * - SetAppID
+ * - AbortList
+ * - BeginList
+ * - AbortList
+ */
+TEST(JumpListBuilder, CheckForRemovals)
+{
+  RefPtr<StrictMock<TestingJumpListBackend>> testBackend =
+      new StrictMock<TestingJumpListBackend>();
+  nsAutoString aumid(u"TestApplicationID");
+  // We set up this expectation here because SetAppID will be called soon
+  // after construction of the JumpListBuilder via the background thread.
+  EXPECT_CALL(*testBackend, SetAppID(_)).Times(1);
+
+  nsCOMPtr<nsIJumpListBuilder> builder =
+      new JumpListBuilder(aumid, testBackend);
+  ASSERT_TRUE(builder);
+
+  EXPECT_CALL(*testBackend, AbortList()).Times(2);
+
+  // Let's prepare BeginList to return a two entry collection of IShellLinks.
+  // The first IShellLink will have the URL be https://example.com, the second
+  // will have the URL be https://mozilla.org.
+  EXPECT_CALL(*testBackend, BeginList)
+      .WillOnce([](UINT* pcMinSlots, REFIID riid, void** ppv) {
+        RefPtr<IObjectCollection> collection;
+        DebugOnly<HRESULT> hr = CoCreateInstance(
+            CLSID_EnumerableObjectCollection, nullptr, CLSCTX_INPROC_SERVER,
+            IID_IObjectCollection, getter_AddRefs(collection));
+        MOZ_ASSERT(SUCCEEDED(hr));
+
+        RefPtr<IShellLinkW> link;
+        hr = CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER,
+                              IID_IShellLinkW, getter_AddRefs(link));
+        MOZ_ASSERT(SUCCEEDED(hr));
+
+        nsAutoString firstLinkHref(u"https://example.com"_ns);
+        link->SetArguments(firstLinkHref.get());
+
+        nsAutoString appPath(u"C:\\Tmp\\firefox.exe"_ns);
+        link->SetIconLocation(appPath.get(), 0);
+
+        collection->AddObject(link);
+
+        // Let's re-use the same IShellLink, but change the URL to add our
+        // second entry. The values of the IShellLink are ultimately copied
+        // over to the items being added to the collection.
+        nsAutoString secondLinkHref(u"https://mozilla.org"_ns);
+        link->SetArguments(secondLinkHref.get());
+        collection->AddObject(link);
+
+        RefPtr<IObjectArray> pArray;
+        hr = collection->QueryInterface(IID_IObjectArray,
+                                        getter_AddRefs(pArray));
+        MOZ_ASSERT(SUCCEEDED(hr));
+
+        *ppv = static_cast<IObjectArray*>(pArray);
+        (static_cast<IUnknown*>(*ppv))->AddRef();
+
+        // This is the default value to return, according to
+        // https://learn.microsoft.com/en-us/windows/win32/api/shobjidl_core/nf-shobjidl_core-icustomdestinationlist-beginlist
+        *pcMinSlots = 10;
+
+        return S_OK;
+      });
+
+  AutoJSAPI jsapi;
+  MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
+  JSContext* cx = jsapi.cx();
+  RefPtr<Promise> promise;
+  nsresult rv = builder->CheckForRemovals(cx, getter_AddRefs(promise));
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+  ASSERT_TRUE(promise);
+
+  RefPtr<WaitForResolver> resolver = new WaitForResolver();
+  promise->AppendNativeHandler(resolver);
+  JS::Rooted<JS::Value> result(cx);
+  resolver->SpinUntilResolvedWithResult(&result);
+
+  ASSERT_TRUE(result.isObject());
+  JS::Rooted<JSObject*> obj(cx, result.toObjectOrNull());
+
+  bool isArray;
+  ASSERT_TRUE(JS::IsArrayObject(cx, obj, &isArray));
+  ASSERT_TRUE(isArray);
+
+  // We should expect to see 2 URL strings returned in the array.
+  uint32_t length = 0;
+  ASSERT_TRUE(JS::GetArrayLength(cx, obj, &length));
+  ASSERT_EQ(length, 2U);
+
+  // The first one should be https://example.com
+  JS::Rooted<JS::Value> firstURLValue(cx);
+  ASSERT_TRUE(JS_GetElement(cx, obj, 0, &firstURLValue));
+  JS::Rooted<JSString*> firstURLJSString(cx, firstURLValue.toString());
+  nsAutoJSString firstURLAutoString;
+  ASSERT_TRUE(firstURLAutoString.init(cx, firstURLJSString));
+
+  ASSERT_TRUE(firstURLAutoString.EqualsLiteral("https://example.com"));
+
+  // The second one should be https://mozilla.org
+  JS::Rooted<JS::Value> secondURLValue(cx);
+  ASSERT_TRUE(JS_GetElement(cx, obj, 1, &secondURLValue));
+  JS::Rooted<JSString*> secondURLJSString(cx, secondURLValue.toString());
+  nsAutoJSString secondURLAutoString;
+  ASSERT_TRUE(secondURLAutoString.init(cx, secondURLJSString));
+
+  ASSERT_TRUE(secondURLAutoString.EqualsLiteral("https://mozilla.org"));
+}
+
+/**
+ * Tests calling PopulateJumpList with empty arguments, which should call the
+ * following methods on the backend, in order:
+ *
+ * - SetAppID
+ * - AbortList
+ * - BeginList
+ * - CommitList
+ *
+ * This should result in an empty jump list for the user.
+ */
+TEST(JumpListBuilder, PopulateJumpListEmpty)
+{
+  RefPtr<StrictMock<TestingJumpListBackend>> testBackend =
+      new StrictMock<TestingJumpListBackend>();
+  nsAutoString aumid(u"TestApplicationID");
+  // We set up this expectation here because SetAppID will be called soon
+  // after construction of the JumpListBuilder via the background thread.
+  EXPECT_CALL(*testBackend, SetAppID(_)).Times(1);
+
+  nsCOMPtr<nsIJumpListBuilder> builder =
+      new JumpListBuilder(aumid, testBackend);
+  ASSERT_TRUE(builder);
+
+  AutoJSAPI jsapi;
+  MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
+  JSContext* cx = jsapi.cx();
+  RefPtr<Promise> promise;
+
+  nsTArray<JS::Value> taskDescJSVals;
+  nsAutoString customTitle(u"");
+  nsTArray<JS::Value> customDescJSVals;
+
+  EXPECT_CALL(*testBackend, AbortList()).Times(1);
+  EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(1);
+  EXPECT_CALL(*testBackend, CommitList()).Times(1);
+  EXPECT_CALL(*testBackend, DeleteList(_)).Times(0);
+
+  nsresult rv =
+      builder->PopulateJumpList(taskDescJSVals, customTitle, customDescJSVals,
+                                cx, getter_AddRefs(promise));
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+  ASSERT_TRUE(promise);
+
+  RefPtr<WaitForResolver> resolver = new WaitForResolver();
+  promise->AppendNativeHandler(resolver);
+  JS::Rooted<JS::Value> result(cx);
+  resolver->SpinUntilResolved();
+}
+
+/**
+ * Tests calling PopulateJumpList with only tasks, and no custom items.
+ * This should call the following methods on the backend, in order:
+ *
+ * - SetAppID
+ * - AbortList
+ * - BeginList
+ * - AddUserTasks
+ * - CommitList
+ *
+ * This should result in a jump list with just tasks shown to the user, and
+ * no custom section.
+ */
+TEST(JumpListBuilder, PopulateJumpListOnlyTasks)
+{
+  RefPtr<StrictMock<TestingJumpListBackend>> testBackend =
+      new StrictMock<TestingJumpListBackend>();
+  nsAutoString aumid(u"TestApplicationID");
+  // We set up this expectation here because SetAppID will be called soon
+  // after construction of the JumpListBuilder via the background thread.
+  EXPECT_CALL(*testBackend, SetAppID(_)).Times(1);
+
+  nsCOMPtr<nsIJumpListBuilder> builder =
+      new JumpListBuilder(aumid, testBackend);
+  ASSERT_TRUE(builder);
+
+  AutoJSAPI jsapi;
+  MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
+  JSContext* cx = jsapi.cx();
+  RefPtr<Promise> promise;
+
+  nsTArray<JS::Value> taskDescJSVals;
+  nsTArray<WindowsJumpListShortcutDescription> taskDescs;
+  GenerateWindowsJumpListShortcutDescriptions(cx, 2, false, taskDescs,
+                                              taskDescJSVals);
+
+  nsAutoString customTitle(u"");
+  nsTArray<JS::Value> customDescJSVals;
+
+  EXPECT_CALL(*testBackend, AbortList()).Times(1);
+  EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(1);
+  EXPECT_CALL(*testBackend, AddUserTasks(ShellLinksEq(&taskDescs))).Times(1);
+
+  EXPECT_CALL(*testBackend, AppendCategory(_, _)).Times(0);
+  EXPECT_CALL(*testBackend, CommitList()).Times(1);
+  EXPECT_CALL(*testBackend, DeleteList(_)).Times(0);
+
+  nsresult rv =
+      builder->PopulateJumpList(taskDescJSVals, customTitle, customDescJSVals,
+                                cx, getter_AddRefs(promise));
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+  ASSERT_TRUE(promise);
+
+  RefPtr<WaitForResolver> resolver = new WaitForResolver();
+  promise->AppendNativeHandler(resolver);
+  JS::Rooted<JS::Value> result(cx);
+  resolver->SpinUntilResolved();
+}
+
+/**
+ * Tests calling PopulateJumpList with only custom items, and no tasks.
+ * This should call the following methods on the backend, in order:
+ *
+ * - SetAppID
+ * - AbortList
+ * - BeginList
+ * - AppendCategory
+ * - CommitList
+ *
+ * This should result in a jump list with just custom items shown to the user,
+ * and no tasks.
+ */
+TEST(JumpListBuilder, PopulateJumpListOnlyCustomItems)
+{
+  RefPtr<StrictMock<TestingJumpListBackend>> testBackend =
+      new StrictMock<TestingJumpListBackend>();
+  nsAutoString aumid(u"TestApplicationID");
+  // We set up this expectation here because SetAppID will be called soon
+  // after construction of the JumpListBuilder via the background thread.
+  EXPECT_CALL(*testBackend, SetAppID(_)).Times(1);
+
+  nsCOMPtr<nsIJumpListBuilder> builder =
+      new JumpListBuilder(aumid, testBackend);
+  ASSERT_TRUE(builder);
+
+  AutoJSAPI jsapi;
+  MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
+  JSContext* cx = jsapi.cx();
+  RefPtr<Promise> promise;
+
+  nsTArray<WindowsJumpListShortcutDescription> descs;
+  nsTArray<JS::Value> customDescJSVals;
+  GenerateWindowsJumpListShortcutDescriptions(cx, 2, false, descs,
+                                              customDescJSVals);
+
+  nsAutoString customTitle(u"My custom title");
+  nsTArray<JS::Value> taskDescJSVals;
+
+  EXPECT_CALL(*testBackend, AbortList()).Times(1);
+  EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(1);
+  EXPECT_CALL(*testBackend, AddUserTasks(_)).Times(0);
+
+  EXPECT_CALL(*testBackend, AppendCategory(LPCWSTREq(customTitle.get()),
+                                           ShellLinksEq(&descs)))
+      .Times(1);
+  EXPECT_CALL(*testBackend, CommitList()).Times(1);
+  EXPECT_CALL(*testBackend, DeleteList(_)).Times(0);
+
+  nsresult rv =
+      builder->PopulateJumpList(taskDescJSVals, customTitle, customDescJSVals,
+                                cx, getter_AddRefs(promise));
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+  ASSERT_TRUE(promise);
+
+  RefPtr<WaitForResolver> resolver = new WaitForResolver();
+  promise->AppendNativeHandler(resolver);
+  JS::Rooted<JS::Value> result(cx);
+  resolver->SpinUntilResolved();
+}
+
+/**
+ * Tests calling PopulateJumpList with tasks and custom items.
+ * This should call the following methods on the backend, in order:
+ *
+ * - SetAppID
+ * - AbortList
+ * - BeginList
+ * - AddUserTasks
+ * - AppendCategory
+ * - CommitList
+ *
+ * This should result in a jump list with both built-in tasks as well as
+ * custom tasks with a custom label.
+ */
+TEST(JumpListBuilder, PopulateJumpList)
+{
+  RefPtr<StrictMock<TestingJumpListBackend>> testBackend =
+      new StrictMock<TestingJumpListBackend>();
+  nsAutoString aumid(u"TestApplicationID");
+  // We set up this expectation here because SetAppID will be called soon
+  // after construction of the JumpListBuilder via the background thread.
+  EXPECT_CALL(*testBackend, SetAppID(_)).Times(1);
+
+  nsCOMPtr<nsIJumpListBuilder> builder =
+      new JumpListBuilder(aumid, testBackend);
+  ASSERT_TRUE(builder);
+
+  AutoJSAPI jsapi;
+  MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
+  JSContext* cx = jsapi.cx();
+  RefPtr<Promise> promise;
+
+  nsTArray<WindowsJumpListShortcutDescription> taskDescs;
+  nsTArray<JS::Value> taskDescJSVals;
+  GenerateWindowsJumpListShortcutDescriptions(cx, 2, false, taskDescs,
+                                              taskDescJSVals);
+
+  nsTArray<WindowsJumpListShortcutDescription> customDescs;
+  nsTArray<JS::Value> customDescJSVals;
+  GenerateWindowsJumpListShortcutDescriptions(cx, 2, false, customDescs,
+                                              customDescJSVals);
+
+  nsAutoString customTitle(u"My custom title");
+
+  EXPECT_CALL(*testBackend, AbortList()).Times(1);
+  EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(1);
+  EXPECT_CALL(*testBackend, AddUserTasks(ShellLinksEq(&taskDescs))).Times(1);
+
+  EXPECT_CALL(*testBackend, AppendCategory(LPCWSTREq(customTitle.get()),
+                                           ShellLinksEq(&customDescs)))
+      .Times(1);
+  EXPECT_CALL(*testBackend, CommitList()).Times(1);
+  EXPECT_CALL(*testBackend, DeleteList(_)).Times(0);
+
+  nsresult rv =
+      builder->PopulateJumpList(taskDescJSVals, customTitle, customDescJSVals,
+                                cx, getter_AddRefs(promise));
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+  ASSERT_TRUE(promise);
+
+  RefPtr<WaitForResolver> resolver = new WaitForResolver();
+  promise->AppendNativeHandler(resolver);
+  JS::Rooted<JS::Value> result(cx);
+  resolver->SpinUntilResolved();
+}
+
+/**
+ * Tests calling ClearJumpList calls the following:
+ *
+ * - SetAppID
+ * - DeleteList (passing the aumid)
+ *
+ * This results in an empty jump list for the user.
+ */
+TEST(JumpListBuilder, ClearJumpList)
+{
+  RefPtr<StrictMock<TestingJumpListBackend>> testBackend =
+      new StrictMock<TestingJumpListBackend>();
+  nsAutoString aumid(u"TestApplicationID");
+  // We set up this expectation here because SetAppID will be called soon
+  // after construction of the JumpListBuilder via the background thread.
+  EXPECT_CALL(*testBackend, SetAppID(_)).Times(1);
+
+  nsCOMPtr<nsIJumpListBuilder> builder =
+      new JumpListBuilder(aumid, testBackend);
+  ASSERT_TRUE(builder);
+
+  AutoJSAPI jsapi;
+  MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
+  JSContext* cx = jsapi.cx();
+  RefPtr<Promise> promise;
+
+  EXPECT_CALL(*testBackend, AbortList()).Times(0);
+  EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(0);
+  EXPECT_CALL(*testBackend, AddUserTasks(_)).Times(0);
+
+  EXPECT_CALL(*testBackend, AppendCategory(_, _)).Times(0);
+  EXPECT_CALL(*testBackend, CommitList()).Times(0);
+  EXPECT_CALL(*testBackend, DeleteList(LPCWSTREq(aumid.get()))).Times(1);
+
+  nsresult rv = builder->ClearJumpList(cx, getter_AddRefs(promise));
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+  ASSERT_TRUE(promise);
+
+  RefPtr<WaitForResolver> resolver = new WaitForResolver();
+  promise->AppendNativeHandler(resolver);
+  JS::Rooted<JS::Value> result(cx);
+  resolver->SpinUntilResolved();
+}
+
+/**
+ * Test that a WindowsJumpListShortcutDescription with a description
+ * longer than MAX_PATH gets truncated to MAX_PATH. This is because a
+ * description longer than MAX_PATH will cause CommitList to fail.
+ */
+TEST(JumpListBuilder, TruncateDescription)
+{
+  RefPtr<StrictMock<TestingJumpListBackend>> testBackend =
+      new StrictMock<TestingJumpListBackend>();
+  nsAutoString aumid(u"TestApplicationID");
+  // We set up this expectation here because SetAppID will be called soon
+  // after construction of the JumpListBuilder via the background thread.
+  EXPECT_CALL(*testBackend, SetAppID(_)).Times(1);
+
+  nsCOMPtr<nsIJumpListBuilder> builder =
+      new JumpListBuilder(aumid, testBackend);
+  ASSERT_TRUE(builder);
+
+  AutoJSAPI jsapi;
+  MOZ_ALWAYS_TRUE(jsapi.Init(xpc::PrivilegedJunkScope()));
+  JSContext* cx = jsapi.cx();
+  RefPtr<Promise> promise;
+
+  nsTArray<WindowsJumpListShortcutDescription> taskDescs;
+  nsTArray<JS::Value> taskDescJSVals;
+  GenerateWindowsJumpListShortcutDescriptions(cx, 2, true, taskDescs,
+                                              taskDescJSVals);
+
+  nsTArray<WindowsJumpListShortcutDescription> customDescs;
+  nsTArray<JS::Value> customDescJSVals;
+  GenerateWindowsJumpListShortcutDescriptions(cx, 2, true, customDescs,
+                                              customDescJSVals);
+  // We expect the long descriptions to be truncated to 260 characters, so
+  // we'll truncate the descriptions here ourselves.
+  for (auto& taskDesc : taskDescs) {
+    taskDesc.mDescription.SetLength(MAX_PATH - 1);
+  }
+  for (auto& customDesc : customDescs) {
+    customDesc.mDescription.SetLength(MAX_PATH - 1);
+  }
+
+  nsAutoString customTitle(u"My custom title");
+
+  EXPECT_CALL(*testBackend, AbortList()).Times(1);
+  EXPECT_CALL(*testBackend, BeginList(_, _, _)).Times(1);
+  EXPECT_CALL(*testBackend, AddUserTasks(ShellLinksEq(&taskDescs))).Times(1);
+
+  EXPECT_CALL(*testBackend, AppendCategory(LPCWSTREq(customTitle.get()),
+                                           ShellLinksEq(&customDescs)))
+      .Times(1);
+  EXPECT_CALL(*testBackend, CommitList()).Times(1);
+  EXPECT_CALL(*testBackend, DeleteList(_)).Times(0);
+
+  nsresult rv =
+      builder->PopulateJumpList(taskDescJSVals, customTitle, customDescJSVals,
+                                cx, getter_AddRefs(promise));
+  ASSERT_TRUE(NS_SUCCEEDED(rv));
+  ASSERT_TRUE(promise);
+
+  RefPtr<WaitForResolver> resolver = new WaitForResolver();
+  promise->AppendNativeHandler(resolver);
+  JS::Rooted<JS::Value> result(cx);
+  resolver->SpinUntilResolved();
+}
diff --git a/widget/windows/tests/gtest/TestWinDND.cpp b/widget/windows/tests/gtest/TestWinDND.cpp
new file mode 100644
index 0000000000..fb7849fd79
--- /dev/null
+++ b/widget/windows/tests/gtest/TestWinDND.cpp
@@ -0,0 +1,728 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// #include <windows.h>
+#include <ole2.h>
+#include <shlobj.h>
+
+#include "nsArray.h"
+#include "nsArrayUtils.h"
+#include "nsComponentManagerUtils.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
+#include "nsIFile.h"
+#include "nsNetUtil.h"
+#include "nsISupportsPrimitives.h"
+#include "nsITransferable.h"
+
+#include "nsClipboard.h"
+#include "nsDataObjCollection.h"
+
+#include "gtest/gtest.h"
+
+// shims for conversion from cppunittest to gtest
+template <size_t N>
+void fail(const char (&msg)[N]) {
+  ADD_FAILURE() << "TEST-UNEXPECTED-FAIL | " << msg;
+}
+template <size_t N>
+void passed(const char (&msg)[N]) {
+  GTEST_SUCCEED() << "TEST-PASS | " << msg;
+}
+
+nsIFile* xferFile;
+
+nsresult CheckValidHDROP(STGMEDIUM* pSTG) {
+  if (pSTG->tymed != TYMED_HGLOBAL) {
+    fail("Received data is not in an HGLOBAL");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  HGLOBAL hGlobal = pSTG->hGlobal;
+  DROPFILES* pDropFiles;
+  pDropFiles = (DROPFILES*)GlobalLock(hGlobal);
+  if (!pDropFiles) {
+    fail("There is no data at the given HGLOBAL");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (pDropFiles->pFiles != sizeof(DROPFILES)) {
+    fail("DROPFILES struct has wrong size");
+  }
+
+  if (!pDropFiles->fWide) {
+    fail("Received data is not Unicode");
+    return NS_ERROR_UNEXPECTED;
+  }
+  nsString s;
+  unsigned long offset = 0;
+  while (true) {
+    s = (char16_t*)((char*)pDropFiles + pDropFiles->pFiles + offset);
+    if (s.IsEmpty()) break;
+    nsresult rv;
+    nsCOMPtr<nsIFile> localFile(
+        do_CreateInstance(NS_LOCAL_FILE_CONTRACTID, &rv));
+    rv = localFile->InitWithPath(s);
+    if (NS_FAILED(rv)) {
+      fail("File could not be opened");
+      return NS_ERROR_UNEXPECTED;
+    }
+    offset += sizeof(char16_t) * (s.Length() + 1);
+  }
+  return NS_OK;
+}
+
+nsresult CheckValidTEXT(STGMEDIUM* pSTG) {
+  if (pSTG->tymed != TYMED_HGLOBAL) {
+    fail("Received data is not in an HGLOBAL");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  HGLOBAL hGlobal = pSTG->hGlobal;
+  char* pText;
+  pText = (char*)GlobalLock(hGlobal);
+  if (!pText) {
+    fail("There is no data at the given HGLOBAL");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsCString string;
+  string = pText;
+
+  if (!string.EqualsLiteral("Mozilla can drag and drop")) {
+    fail("Text passed through drop object wrong");
+    return NS_ERROR_UNEXPECTED;
+  }
+  return NS_OK;
+}
+
+nsresult CheckValidTEXTTwo(STGMEDIUM* pSTG) {
+  if (pSTG->tymed != TYMED_HGLOBAL) {
+    fail("Received data is not in an HGLOBAL");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  HGLOBAL hGlobal = pSTG->hGlobal;
+  char* pText;
+  pText = (char*)GlobalLock(hGlobal);
+  if (!pText) {
+    fail("There is no data at the given HGLOBAL");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsCString string;
+  string = pText;
+
+  if (!string.EqualsLiteral("Mozilla can drag and drop twice over")) {
+    fail("Text passed through drop object wrong");
+    return NS_ERROR_UNEXPECTED;
+  }
+  return NS_OK;
+}
+
+nsresult CheckValidUNICODE(STGMEDIUM* pSTG) {
+  if (pSTG->tymed != TYMED_HGLOBAL) {
+    fail("Received data is not in an HGLOBAL");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  HGLOBAL hGlobal = pSTG->hGlobal;
+  char16_t* pText;
+  pText = (char16_t*)GlobalLock(hGlobal);
+  if (!pText) {
+    fail("There is no data at the given HGLOBAL");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsString string;
+  string = pText;
+
+  if (!string.EqualsLiteral("Mozilla can drag and drop")) {
+    fail("Text passed through drop object wrong");
+    return NS_ERROR_UNEXPECTED;
+  }
+  return NS_OK;
+}
+
+nsresult CheckValidUNICODETwo(STGMEDIUM* pSTG) {
+  if (pSTG->tymed != TYMED_HGLOBAL) {
+    fail("Received data is not in an HGLOBAL");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  HGLOBAL hGlobal = pSTG->hGlobal;
+  char16_t* pText;
+  pText = (char16_t*)GlobalLock(hGlobal);
+  if (!pText) {
+    fail("There is no data at the given HGLOBAL");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  nsString string;
+  string = pText;
+
+  if (!string.EqualsLiteral("Mozilla can drag and drop twice over")) {
+    fail("Text passed through drop object wrong");
+    return NS_ERROR_UNEXPECTED;
+  }
+  return NS_OK;
+}
+
+nsresult GetTransferableFile(nsCOMPtr<nsITransferable>& pTransferable) {
+  nsresult rv;
+
+  nsCOMPtr<nsISupports> genericWrapper = do_QueryInterface(xferFile);
+
+  pTransferable = do_CreateInstance("@mozilla.org/widget/transferable;1");
+  pTransferable->Init(nullptr);
+  rv = pTransferable->SetTransferData("application/x-moz-file", genericWrapper);
+  return rv;
+}
+
+nsresult GetTransferableText(nsCOMPtr<nsITransferable>& pTransferable) {
+  nsresult rv;
+  constexpr auto mozString = u"Mozilla can drag and drop"_ns;
+  nsCOMPtr<nsISupportsString> xferString =
+      do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID);
+  rv = xferString->SetData(mozString);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsISupports> genericWrapper = do_QueryInterface(xferString);
+
+  pTransferable = do_CreateInstance("@mozilla.org/widget/transferable;1");
+  pTransferable->Init(nullptr);
+  rv = pTransferable->SetTransferData("text/plain", genericWrapper);
+  return rv;
+}
+
+nsresult GetTransferableTextTwo(nsCOMPtr<nsITransferable>& pTransferable) {
+  nsresult rv;
+  constexpr auto mozString = u" twice over"_ns;
+  nsCOMPtr<nsISupportsString> xferString =
+      do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID);
+  rv = xferString->SetData(mozString);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsISupports> genericWrapper = do_QueryInterface(xferString);
+
+  pTransferable = do_CreateInstance("@mozilla.org/widget/transferable;1");
+  pTransferable->Init(nullptr);
+  rv = pTransferable->SetTransferData("text/plain", genericWrapper);
+  return rv;
+}
+
+nsresult GetTransferableURI(nsCOMPtr<nsITransferable>& pTransferable) {
+  nsresult rv;
+
+  nsCOMPtr<nsIURI> xferURI;
+
+  rv = NS_NewURI(getter_AddRefs(xferURI), "http://www.mozilla.org");
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsISupports> genericWrapper = do_QueryInterface(xferURI);
+
+  pTransferable = do_CreateInstance("@mozilla.org/widget/transferable;1");
+  pTransferable->Init(nullptr);
+  rv = pTransferable->SetTransferData("text/x-moz-url", genericWrapper);
+  return rv;
+}
+
+nsresult MakeDataObject(nsIArray* transferableArray,
+                        RefPtr<IDataObject>& itemToDrag) {
+  nsresult rv;
+  uint32_t itemCount = 0;
+
+  nsCOMPtr<nsIURI> uri;
+  rv = NS_NewURI(getter_AddRefs(uri), "http://www.mozilla.org");
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = transferableArray->GetLength(&itemCount);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Copied more or less exactly from nsDragService::InvokeDragSession
+  // This is what lets us play fake Drag Service for the test
+  if (itemCount > 1) {
+    nsDataObjCollection* dataObjCollection = new nsDataObjCollection();
+    if (!dataObjCollection) return NS_ERROR_OUT_OF_MEMORY;
+    itemToDrag = dataObjCollection;
+    for (uint32_t i = 0; i < itemCount; ++i) {
+      nsCOMPtr<nsITransferable> trans = do_QueryElementAt(transferableArray, i);
+      if (trans) {
+        RefPtr<IDataObject> dataObj;
+        rv = nsClipboard::CreateNativeDataObject(trans, getter_AddRefs(dataObj),
+                                                 uri);
+        NS_ENSURE_SUCCESS(rv, rv);
+        // Add the flavors to the collection object too
+        rv = nsClipboard::SetupNativeDataObject(trans, dataObjCollection);
+        NS_ENSURE_SUCCESS(rv, rv);
+
+        dataObjCollection->AddDataObject(dataObj);
+      }
+    }
+  }  // if dragging multiple items
+  else {
+    nsCOMPtr<nsITransferable> trans = do_QueryElementAt(transferableArray, 0);
+    if (trans) {
+      rv = nsClipboard::CreateNativeDataObject(trans,
+                                               getter_AddRefs(itemToDrag), uri);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }  // else dragging a single object
+  return rv;
+}
+
+nsresult Do_CheckOneFile() {
+  nsresult rv;
+  nsCOMPtr<nsITransferable> transferable;
+  nsCOMPtr<nsIMutableArray> transferableArray = nsArray::Create();
+  nsCOMPtr<nsISupports> genericWrapper;
+  RefPtr<IDataObject> dataObj;
+
+  rv = GetTransferableFile(transferable);
+  if (NS_FAILED(rv)) {
+    fail("Could not create the proper nsITransferable!");
+    return rv;
+  }
+  genericWrapper = do_QueryInterface(transferable);
+  rv = transferableArray->AppendElement(genericWrapper);
+  if (NS_FAILED(rv)) {
+    fail("Could not append element to transferable array");
+    return rv;
+  }
+
+  rv = MakeDataObject(transferableArray, dataObj);
+  if (NS_FAILED(rv)) {
+    fail("Could not create data object");
+    return rv;
+  }
+
+  FORMATETC fe;
+  SET_FORMATETC(fe, CF_HDROP, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+  if (dataObj->QueryGetData(&fe) != S_OK) {
+    fail("File data object does not support the file data type!");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  STGMEDIUM* stg;
+  stg = (STGMEDIUM*)CoTaskMemAlloc(sizeof(STGMEDIUM));
+  if (dataObj->GetData(&fe, stg) != S_OK) {
+    fail("File data object did not provide data on request");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  rv = CheckValidHDROP(stg);
+  if (NS_FAILED(rv)) {
+    fail("HDROP was invalid");
+    return rv;
+  }
+
+  ReleaseStgMedium(stg);
+
+  return NS_OK;
+}
+
+nsresult Do_CheckTwoFiles() {
+  nsresult rv;
+  nsCOMPtr<nsITransferable> transferable;
+  nsCOMPtr<nsIMutableArray> transferableArray = nsArray::Create();
+  nsCOMPtr<nsISupports> genericWrapper;
+  RefPtr<IDataObject> dataObj;
+
+  rv = GetTransferableFile(transferable);
+  if (NS_FAILED(rv)) {
+    fail("Could not create the proper nsITransferable!");
+    return rv;
+  }
+  genericWrapper = do_QueryInterface(transferable);
+  rv = transferableArray->AppendElement(genericWrapper);
+  if (NS_FAILED(rv)) {
+    fail("Could not append element to transferable array");
+    return rv;
+  }
+
+  rv = GetTransferableFile(transferable);
+  if (NS_FAILED(rv)) {
+    fail("Could not create the proper nsITransferable!");
+    return rv;
+  }
+  genericWrapper = do_QueryInterface(transferable);
+  rv = transferableArray->AppendElement(genericWrapper);
+  if (NS_FAILED(rv)) {
+    fail("Could not append element to transferable array");
+    return rv;
+  }
+
+  rv = MakeDataObject(transferableArray, dataObj);
+  if (NS_FAILED(rv)) {
+    fail("Could not create data object");
+    return rv;
+  }
+
+  FORMATETC fe;
+  SET_FORMATETC(fe, CF_HDROP, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+  if (dataObj->QueryGetData(&fe) != S_OK) {
+    fail("File data object does not support the file data type!");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  STGMEDIUM* stg;
+  stg = (STGMEDIUM*)CoTaskMemAlloc(sizeof(STGMEDIUM));
+  if (dataObj->GetData(&fe, stg) != S_OK) {
+    fail("File data object did not provide data on request");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  rv = CheckValidHDROP(stg);
+  if (NS_FAILED(rv)) {
+    fail("HDROP was invalid");
+    return rv;
+  }
+
+  ReleaseStgMedium(stg);
+
+  return NS_OK;
+}
+
+nsresult Do_CheckOneString() {
+  nsresult rv;
+  nsCOMPtr<nsITransferable> transferable;
+  nsCOMPtr<nsIMutableArray> transferableArray = nsArray::Create();
+  nsCOMPtr<nsISupports> genericWrapper;
+  RefPtr<IDataObject> dataObj;
+
+  rv = GetTransferableText(transferable);
+  if (NS_FAILED(rv)) {
+    fail("Could not create the proper nsITransferable!");
+    return rv;
+  }
+  genericWrapper = do_QueryInterface(transferable);
+  rv = transferableArray->AppendElement(genericWrapper);
+  if (NS_FAILED(rv)) {
+    fail("Could not append element to transferable array");
+    return rv;
+  }
+
+  rv = MakeDataObject(transferableArray, dataObj);
+  if (NS_FAILED(rv)) {
+    fail("Could not create data object");
+    return rv;
+  }
+
+  FORMATETC fe;
+  SET_FORMATETC(fe, CF_TEXT, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+  if (dataObj->QueryGetData(&fe) != S_OK) {
+    fail("String data object does not support the ASCII text data type!");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  STGMEDIUM* stg;
+  stg = (STGMEDIUM*)CoTaskMemAlloc(sizeof(STGMEDIUM));
+  if (dataObj->GetData(&fe, stg) != S_OK) {
+    fail("String data object did not provide ASCII data on request");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  rv = CheckValidTEXT(stg);
+  if (NS_FAILED(rv)) {
+    fail("TEXT was invalid");
+    return rv;
+  }
+
+  ReleaseStgMedium(stg);
+
+  SET_FORMATETC(fe, CF_UNICODETEXT, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+  if (dataObj->QueryGetData(&fe) != S_OK) {
+    fail("String data object does not support the wide text data type!");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (dataObj->GetData(&fe, stg) != S_OK) {
+    fail("String data object did not provide wide data on request");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  rv = CheckValidUNICODE(stg);
+  if (NS_FAILED(rv)) {
+    fail("UNICODE was invalid");
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult Do_CheckTwoStrings() {
+  nsresult rv;
+  nsCOMPtr<nsITransferable> transferable;
+  nsCOMPtr<nsIMutableArray> transferableArray = nsArray::Create();
+  nsCOMPtr<nsISupports> genericWrapper;
+  RefPtr<IDataObject> dataObj;
+
+  rv = GetTransferableText(transferable);
+  if (NS_FAILED(rv)) {
+    fail("Could not create the proper nsITransferable!");
+    return rv;
+  }
+  genericWrapper = do_QueryInterface(transferable);
+  rv = transferableArray->AppendElement(genericWrapper);
+  if (NS_FAILED(rv)) {
+    fail("Could not append element to transferable array");
+    return rv;
+  }
+
+  rv = GetTransferableTextTwo(transferable);
+  if (NS_FAILED(rv)) {
+    fail("Could not create the proper nsITransferable!");
+    return rv;
+  }
+  genericWrapper = do_QueryInterface(transferable);
+  rv = transferableArray->AppendElement(genericWrapper);
+  if (NS_FAILED(rv)) {
+    fail("Could not append element to transferable array");
+    return rv;
+  }
+
+  rv = MakeDataObject(transferableArray, dataObj);
+  if (NS_FAILED(rv)) {
+    fail("Could not create data object");
+    return rv;
+  }
+
+  FORMATETC fe;
+  SET_FORMATETC(fe, CF_TEXT, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+  if (dataObj->QueryGetData(&fe) != S_OK) {
+    fail("String data object does not support the ASCII text data type!");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  STGMEDIUM* stg;
+  stg = (STGMEDIUM*)CoTaskMemAlloc(sizeof(STGMEDIUM));
+  if (dataObj->GetData(&fe, stg) != S_OK) {
+    fail("String data object did not provide ASCII data on request");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  rv = CheckValidTEXTTwo(stg);
+  if (NS_FAILED(rv)) {
+    fail("TEXT was invalid");
+    return rv;
+  }
+
+  ReleaseStgMedium(stg);
+
+  SET_FORMATETC(fe, CF_UNICODETEXT, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+  if (dataObj->QueryGetData(&fe) != S_OK) {
+    fail("String data object does not support the wide text data type!");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (dataObj->GetData(&fe, stg) != S_OK) {
+    fail("String data object did not provide wide data on request");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  rv = CheckValidUNICODETwo(stg);
+  if (NS_FAILED(rv)) {
+    fail("UNICODE was invalid");
+    return rv;
+  }
+
+  return NS_OK;
+}
+
+nsresult Do_CheckSetArbitraryData(bool aMultiple) {
+  nsresult rv;
+  nsCOMPtr<nsITransferable> transferable;
+  nsCOMPtr<nsIMutableArray> transferableArray = nsArray::Create();
+  nsCOMPtr<nsISupports> genericWrapper;
+  RefPtr<IDataObject> dataObj;
+
+  rv = GetTransferableText(transferable);
+  if (NS_FAILED(rv)) {
+    fail("Could not create the proper nsITransferable!");
+    return rv;
+  }
+  genericWrapper = do_QueryInterface(transferable);
+  rv = transferableArray->AppendElement(genericWrapper);
+  if (NS_FAILED(rv)) {
+    fail("Could not append element to transferable array");
+    return rv;
+  }
+
+  if (aMultiple) {
+    rv = GetTransferableText(transferable);
+    if (NS_FAILED(rv)) {
+      fail("Could not create the proper nsITransferable!");
+      return rv;
+    }
+    genericWrapper = do_QueryInterface(transferable);
+    rv = transferableArray->AppendElement(genericWrapper);
+    if (NS_FAILED(rv)) {
+      fail("Could not append element to transferable array");
+      return rv;
+    }
+  }
+
+  rv = MakeDataObject(transferableArray, dataObj);
+  if (NS_FAILED(rv)) {
+    fail("Could not create data object");
+    return rv;
+  }
+
+  static CLIPFORMAT mozArbitraryFormat =
+      ::RegisterClipboardFormatW(L"MozillaTestFormat");
+  FORMATETC fe;
+  STGMEDIUM stg;
+  SET_FORMATETC(fe, mozArbitraryFormat, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL);
+
+  HGLOBAL hg = GlobalAlloc(GPTR, 1024);
+  stg.tymed = TYMED_HGLOBAL;
+  stg.hGlobal = hg;
+  stg.pUnkForRelease = nullptr;
+
+  if (dataObj->SetData(&fe, &stg, true) != S_OK) {
+    if (aMultiple) {
+      fail("Unable to set arbitrary data type on data object collection!");
+    } else {
+      fail("Unable to set arbitrary data type on data object!");
+    }
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (dataObj->QueryGetData(&fe) != S_OK) {
+    fail("Arbitrary data set on data object is not advertised!");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  STGMEDIUM* stg2;
+  stg2 = (STGMEDIUM*)CoTaskMemAlloc(sizeof(STGMEDIUM));
+  if (dataObj->GetData(&fe, stg2) != S_OK) {
+    fail("Data object did not provide arbitrary data upon request!");
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  if (stg2->hGlobal != hg) {
+    fail("Arbitrary data was not returned properly!");
+    return rv;
+  }
+  ReleaseStgMedium(stg2);
+
+  return NS_OK;
+}
+
+// This function performs basic drop tests, testing a data object consisting
+// of one transferable
+nsresult Do_Test1() {
+  nsresult rv = NS_OK;
+  nsresult workingrv;
+
+  workingrv = Do_CheckOneFile();
+  if (NS_FAILED(workingrv)) {
+    fail("Drag object tests failed on a single file");
+    rv = NS_ERROR_UNEXPECTED;
+  } else {
+    passed("Successfully created a working file drag object!");
+  }
+
+  workingrv = Do_CheckOneString();
+  if (NS_FAILED(workingrv)) {
+    fail("Drag object tests failed on a single string");
+    rv = NS_ERROR_UNEXPECTED;
+  } else {
+    passed("Successfully created a working string drag object!");
+  }
+
+  workingrv = Do_CheckSetArbitraryData(false);
+  if (NS_FAILED(workingrv)) {
+    fail("Drag object tests failed on setting arbitrary data");
+    rv = NS_ERROR_UNEXPECTED;
+  } else {
+    passed("Successfully set arbitrary data on a drag object");
+  }
+
+  return rv;
+}
+
+// This function performs basic drop tests, testing a data object consisting of
+// two transferables.
+nsresult Do_Test2() {
+  nsresult rv = NS_OK;
+  nsresult workingrv;
+
+  workingrv = Do_CheckTwoFiles();
+  if (NS_FAILED(workingrv)) {
+    fail("Drag object tests failed on multiple files");
+    rv = NS_ERROR_UNEXPECTED;
+  } else {
+    passed("Successfully created a working multiple file drag object!");
+  }
+
+  workingrv = Do_CheckTwoStrings();
+  if (NS_FAILED(workingrv)) {
+    fail("Drag object tests failed on multiple strings");
+    rv = NS_ERROR_UNEXPECTED;
+  } else {
+    passed("Successfully created a working multiple string drag object!");
+  }
+
+  workingrv = Do_CheckSetArbitraryData(true);
+  if (NS_FAILED(workingrv)) {
+    fail("Drag object tests failed on setting arbitrary data");
+    rv = NS_ERROR_UNEXPECTED;
+  } else {
+    passed("Successfully set arbitrary data on a drag object");
+  }
+
+  return rv;
+}
+
+// This function performs advanced drag and drop tests, testing a data object
+// consisting of multiple transferables that have different data types
+nsresult Do_Test3() {
+  nsresult rv = NS_OK;
+  // nsresult workingrv;
+
+  // XXX TODO Write more advanced tests in Bug 535860
+  return rv;
+}
+
+nsCOMPtr<nsIFile> GetTemporaryDirectory() {
+  nsCOMPtr<nsIFile> tmpdir;
+
+#define ENSURE(expr) NS_ENSURE_SUCCESS(expr, nullptr);
+
+  ENSURE(NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(tmpdir)));
+  MOZ_ASSERT(tmpdir);
+
+  ENSURE(tmpdir->AppendNative("TestWinDND"_ns));
+  ENSURE(tmpdir->CreateUnique(nsIFile::DIRECTORY_TYPE, 0777));
+
+#undef ENSURE
+
+  return tmpdir;
+}
+
+TEST(TestWinDND, All)
+{
+  nsCOMPtr<nsIFile> file = GetTemporaryDirectory();
+  if (!file) {
+    fail("could not create temporary directory!");
+    return;
+  }
+  xferFile = file;
+
+  if (NS_SUCCEEDED(Do_Test1())) {
+    passed(
+        "Basic Drag and Drop data type tests (single transferable) succeeded!");
+  }
+
+  if (NS_SUCCEEDED(Do_Test2())) {
+    passed(
+        "Basic Drag and Drop data type tests (multiple transferables) "
+        "succeeded!");
+  }
+
+  // if (NS_SUCCEEDED(Do_Test3()))
+  //  passed("Advanced Drag and Drop data type tests succeeded!");
+}
diff --git a/widget/windows/tests/gtest/moz.build b/widget/windows/tests/gtest/moz.build
new file mode 100644
index 0000000000..4057b7ae57
--- /dev/null
+++ b/widget/windows/tests/gtest/moz.build
@@ -0,0 +1,19 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+UNIFIED_SOURCES += [
+    "TestJumpListBuilder.cpp",
+    "TestWinDND.cpp",
+]
+
+LOCAL_INCLUDES += [
+    "/widget",
+    "/widget/windows",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul-gtest"
diff --git a/widget/windows/tests/moz.build b/widget/windows/tests/moz.build
new file mode 100644
index 0000000000..2c7d200571
--- /dev/null
+++ b/widget/windows/tests/moz.build
@@ -0,0 +1,33 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+GeckoCppUnitTests(
+    [
+        "TestUriValidation",
+    ],
+    linkage=None,
+)
+
+DIRS = ["gtest"]
+
+LOCAL_INCLUDES += []
+
+OS_LIBS += [
+    "oleaut32",
+    "ole32",
+    "shell32",
+    "shlwapi",
+    "urlmon",
+    "uuid",
+]
+
+if CONFIG["OS_TARGET"] == "WINNT" and CONFIG["CC_TYPE"] in ("gcc", "clang"):
+    # This allows us to use wmain as the entry point on mingw
+    LDFLAGS += [
+        "-municode",
+    ]
+
+XPCSHELL_TESTS_MANIFESTS += ["unit/xpcshell.toml"]
diff --git a/widget/windows/tests/unit/test_windows_alert_service.js b/widget/windows/tests/unit/test_windows_alert_service.js
new file mode 100644
index 0000000000..0ba0d2a4d4
--- /dev/null
+++ b/widget/windows/tests/unit/test_windows_alert_service.js
@@ -0,0 +1,667 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Test that Windows alert notifications generate expected XML.
+ */
+
+var { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+
+let gProfD = do_get_profile();
+
+// Setup that allows to use the profile service in xpcshell tests,
+// lifted from `toolkit/profile/xpcshell/head.js`.
+function setupProfileService() {
+  let gDataHome = gProfD.clone();
+  gDataHome.append("data");
+  gDataHome.createUnique(Ci.nsIFile.DIRECTORY_TYPE, 0o755);
+  let gDataHomeLocal = gProfD.clone();
+  gDataHomeLocal.append("local");
+  gDataHomeLocal.createUnique(Ci.nsIFile.DIRECTORY_TYPE, 0o755);
+
+  let xreDirProvider = Cc["@mozilla.org/xre/directory-provider;1"].getService(
+    Ci.nsIXREDirProvider
+  );
+  xreDirProvider.setUserDataDirectory(gDataHome, false);
+  xreDirProvider.setUserDataDirectory(gDataHomeLocal, true);
+}
+
+add_setup(setupProfileService);
+
+function makeAlert(options) {
+  var alert = Cc["@mozilla.org/alert-notification;1"].createInstance(
+    Ci.nsIAlertNotification
+  );
+  alert.init(
+    options.name,
+    options.imageURL,
+    options.title,
+    options.text,
+    options.textClickable,
+    options.cookie,
+    options.dir,
+    options.lang,
+    options.data,
+    options.principal,
+    options.inPrivateBrowsing,
+    options.requireInteraction,
+    options.silent,
+    options.vibrate || []
+  );
+  if (options.actions) {
+    alert.actions = options.actions;
+  }
+  if (options.opaqueRelaunchData) {
+    alert.opaqueRelaunchData = options.opaqueRelaunchData;
+  }
+  return alert;
+}
+
+/**
+ * Take a `key1\nvalue1\n...` string encoding as used by the Windows native
+ * notification server DLL, and split it into an object, keeping `action\n...`
+ * intact.
+ *
+ * @param {string} t string encoding.
+ * @returns {object} an object with keys and values.
+ */
+function parseOneEncoded(t) {
+  var launch = {};
+
+  var lines = t.split("\n");
+  while (lines.length) {
+    var key = lines.shift();
+    var value;
+    if (key === "action") {
+      value = lines.join("\n");
+      lines = [];
+    } else {
+      value = lines.shift();
+    }
+    launch[key] = value;
+  }
+
+  return launch;
+}
+
+/**
+ * This complicated-looking function takes a (XML) string representation of a
+ * Windows alert (toast notification), parses it into XML, extracts and further
+ * parses internal data, and returns a simplified XML representation together
+ * with the parsed internals.
+ *
+ * Doing this lets us compare JSON objects rather than stringified-JSON further
+ * encoded as XML strings, which have lots of slashes and `&quot;` characters to
+ * contend with.
+ *
+ * @param {string} s XML string for Windows alert.
+
+ * @returns {Array} a pair of a simplified XML string and an object with
+ *                  `launch` and `actions` keys.
+ */
+function parseLaunchAndActions(s) {
+  var document = new DOMParser().parseFromString(s, "text/xml");
+  var root = document.documentElement;
+
+  var launchString = root.getAttribute("launch");
+  root.setAttribute("launch", "launch");
+  var launch = parseOneEncoded(launchString);
+
+  // `actions` is keyed by "content" attribute.
+  let actions = {};
+  for (var actionElement of root.querySelectorAll("action")) {
+    // `activationType="system"` is special.  Leave them alone.
+    let systemActivationType =
+      actionElement.getAttribute("activationType") === "system";
+
+    let action = {};
+    let names = [...actionElement.attributes].map(attribute => attribute.name);
+
+    for (var name of names) {
+      let value = actionElement.getAttribute(name);
+
+      // Here is where we parse stringified-JSON to simplify comparisons.
+      if (value.startsWith("{")) {
+        value = JSON.parse(value);
+        if ("opaqueRelaunchData" in value) {
+          value.opaqueRelaunchData = JSON.parse(value.opaqueRelaunchData);
+        }
+      }
+
+      if (name == "arguments" && !systemActivationType) {
+        action[name] = parseOneEncoded(value);
+      } else {
+        action[name] = value;
+      }
+
+      if (name != "content" && !systemActivationType) {
+        actionElement.removeAttribute(name);
+      }
+    }
+
+    let actionName = actionElement.getAttribute("content");
+    actions[actionName] = action;
+  }
+
+  return [new XMLSerializer().serializeToString(document), { launch, actions }];
+}
+
+function escape(s) {
+  return s
+    .replace(/&/g, "&amp;")
+    .replace(/"/g, "&quot;")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;")
+    .replace(/\n/g, "&#xA;");
+}
+
+function unescape(s) {
+  return s
+    .replace(/&amp;/g, "&")
+    .replace(/&quot;/g, '"')
+    .replace(/&lt;/g, "<")
+    .replace(/&gt;/g, ">")
+    .replace(/&#xA;/g, "\n");
+}
+
+function testAlert(when, { serverEnabled, profD, isBackgroundTaskMode } = {}) {
+  let argumentString = action => {
+    // &#xA; is "\n".
+    let s = ``;
+    if (serverEnabled) {
+      s += `program&#xA;${AppConstants.MOZ_APP_NAME}`;
+    } else {
+      s += `invalid key&#xA;invalid value`;
+    }
+    if (serverEnabled && profD) {
+      s += `&#xA;profile&#xA;${profD.path}`;
+    }
+    if (serverEnabled) {
+      s += "&#xA;windowsTag&#xA;";
+    }
+    if (action) {
+      s += `&#xA;action&#xA;${escape(JSON.stringify(action))}`;
+    }
+
+    return s;
+  };
+
+  let parsedArgumentString = action =>
+    parseOneEncoded(unescape(argumentString(action)));
+
+  let settingsAction = isBackgroundTaskMode
+    ? ""
+    : `<action content="Notification settings"/>`;
+
+  let parsedSettingsAction = hostport => {
+    if (isBackgroundTaskMode) {
+      return [];
+    }
+    let content = "Notification settings";
+    return [
+      content,
+      {
+        content,
+        arguments: parsedArgumentString(
+          Object.assign(
+            {
+              action: "settings",
+            },
+            hostport && {
+              launchUrl: hostport,
+            }
+          )
+        ),
+        placement: "contextmenu",
+      },
+    ];
+  };
+
+  let parsedSnoozeAction = hostport => {
+    let content = `Disable notifications from ${hostport}`;
+    return [
+      content,
+      {
+        content,
+        arguments: parsedArgumentString(
+          Object.assign(
+            {
+              action: "snooze",
+            },
+            hostport && {
+              launchUrl: hostport,
+            }
+          )
+        ),
+        placement: "contextmenu",
+      },
+    ];
+  };
+
+  let alertsService = Cc["@mozilla.org/system-alerts-service;1"]
+    .getService(Ci.nsIAlertsService)
+    .QueryInterface(Ci.nsIWindowsAlertsService);
+
+  let name = "name";
+  let title = "title";
+  let text = "text";
+  let imageURL = "file:///image.png";
+  let actions = [
+    { action: "action1", title: "title1", iconURL: "file:///iconURL1.png" },
+    { action: "action2", title: "title2", iconURL: "file:///iconURL2.png" },
+  ];
+  let opaqueRelaunchData = { foo: 1, bar: "two" };
+
+  let alert = makeAlert({ name, title, text });
+  let expected = `<toast launch="launch"><visual><binding template="ToastText03"><text id="1">title</text><text id="2">text</text></binding></visual><actions>${settingsAction}</actions></toast>`;
+  Assert.deepEqual(
+    [
+      expected.replace("<actions></actions>", "<actions/>"),
+      {
+        launch: parsedArgumentString({ action: "" }),
+        actions: Object.fromEntries(
+          [parsedSettingsAction()].filter(x => x.length)
+        ),
+      },
+    ],
+    parseLaunchAndActions(alertsService.getXmlStringForWindowsAlert(alert)),
+    when
+  );
+
+  alert = makeAlert({ name, title, text, imageURL });
+  expected = `<toast launch="launch"><visual><binding template="ToastImageAndText03"><image id="1" src="file:///image.png"/><text id="1">title</text><text id="2">text</text></binding></visual><actions>${settingsAction}</actions></toast>`;
+  Assert.deepEqual(
+    [
+      expected.replace("<actions></actions>", "<actions/>"),
+      {
+        launch: parsedArgumentString({ action: "" }),
+        actions: Object.fromEntries(
+          [parsedSettingsAction()].filter(x => x.length)
+        ),
+      },
+    ],
+    parseLaunchAndActions(alertsService.getXmlStringForWindowsAlert(alert)),
+    when
+  );
+
+  alert = makeAlert({ name, title, text, imageURL, requireInteraction: true });
+  expected = `<toast scenario="reminder" launch="launch"><visual><binding template="ToastImageAndText03"><image id="1" src="file:///image.png"/><text id="1">title</text><text id="2">text</text></binding></visual><actions>${settingsAction}<action content="Dismiss" arguments="dismiss" activationType="system"/></actions></toast>`;
+  Assert.deepEqual(
+    [
+      expected.replace("<actions></actions>", "<actions/>"),
+      {
+        launch: parsedArgumentString({ action: "" }),
+        actions: Object.fromEntries(
+          [
+            parsedSettingsAction(),
+            [
+              "Dismiss",
+              {
+                content: "Dismiss",
+                arguments: "dismiss",
+                activationType: "system",
+              },
+            ],
+          ].filter(x => x.length)
+        ),
+      },
+    ],
+    parseLaunchAndActions(alertsService.getXmlStringForWindowsAlert(alert)),
+    when
+  );
+
+  alert = makeAlert({ name, title, text, imageURL, actions });
+  expected = `<toast launch="launch"><visual><binding template="ToastImageAndText03"><image id="1" src="file:///image.png"/><text id="1">title</text><text id="2">text</text></binding></visual><actions>${settingsAction}<action content="title1"/><action content="title2"/></actions></toast>`;
+  Assert.deepEqual(
+    [
+      expected.replace("<actions></actions>", "<actions/>"),
+      {
+        launch: parsedArgumentString({ action: "" }),
+        actions: Object.fromEntries(
+          [
+            parsedSettingsAction(),
+            [
+              "title1",
+              {
+                content: "title1",
+                arguments: parsedArgumentString({ action: "action1" }),
+              },
+            ],
+            [
+              "title2",
+              {
+                content: "title2",
+                arguments: parsedArgumentString({ action: "action2" }),
+              },
+            ],
+          ].filter(x => x.length)
+        ),
+      },
+    ],
+    parseLaunchAndActions(alertsService.getXmlStringForWindowsAlert(alert)),
+    when
+  );
+
+  // Chrome privileged alerts can use `windowsSystemActivationType`.
+  let systemActions = [
+    {
+      action: "dismiss",
+      title: "dismissTitle",
+      windowsSystemActivationType: true,
+    },
+    {
+      action: "snooze",
+      title: "snoozeTitle",
+      windowsSystemActivationType: true,
+    },
+  ];
+  let systemPrincipal = Services.scriptSecurityManager.getSystemPrincipal();
+  alert = makeAlert({
+    name,
+    title,
+    text,
+    imageURL,
+    principal: systemPrincipal,
+    actions: systemActions,
+  });
+  let parsedSettingsActionWithPrivilegedName = isBackgroundTaskMode
+    ? []
+    : [
+        "Notification settings",
+        {
+          content: "Notification settings",
+          arguments: parsedArgumentString({
+            action: "settings",
+            privilegedName: name,
+          }),
+          placement: "contextmenu",
+        },
+      ];
+
+  expected = `<toast launch="launch"><visual><binding template="ToastGeneric"><image id="1" src="file:///image.png"/><text id="1">title</text><text id="2">text</text></binding></visual><actions>${settingsAction}<action content="dismissTitle" arguments="dismiss" activationType="system"/><action content="snoozeTitle" arguments="snooze" activationType="system"/></actions></toast>`;
+  Assert.deepEqual(
+    [
+      expected.replace("<actions></actions>", "<actions/>"),
+      {
+        launch: parsedArgumentString({ action: "", privilegedName: name }),
+        actions: Object.fromEntries(
+          [
+            parsedSettingsActionWithPrivilegedName,
+            [
+              "dismissTitle",
+              {
+                content: "dismissTitle",
+                arguments: "dismiss",
+                activationType: "system",
+              },
+            ],
+            [
+              "snoozeTitle",
+              {
+                content: "snoozeTitle",
+                arguments: "snooze",
+                activationType: "system",
+              },
+            ],
+          ].filter(x => x.length)
+        ),
+      },
+    ],
+    parseLaunchAndActions(alertsService.getXmlStringForWindowsAlert(alert)),
+    when
+  );
+
+  // But content unprivileged alerts can't use `windowsSystemActivationType`.
+  let launchUrl = "https://example.com/foo/bar.html";
+  const principaluri = Services.io.newURI(launchUrl);
+  const principal = Services.scriptSecurityManager.createContentPrincipal(
+    principaluri,
+    {}
+  );
+
+  alert = makeAlert({
+    name,
+    title,
+    text,
+    imageURL,
+    actions: systemActions,
+    principal,
+  });
+  expected = `<toast launch="launch"><visual><binding template="ToastImageAndText04"><image id="1" src="file:///image.png"/><text id="1">title</text><text id="2">text</text><text id="3" placement="attribution">via example.com</text></binding></visual><actions><action content="Disable notifications from example.com"/>${settingsAction}<action content="dismissTitle"/><action content="snoozeTitle"/></actions></toast>`;
+  Assert.deepEqual(
+    [
+      expected.replace("<actions></actions>", "<actions/>"),
+      {
+        launch: parsedArgumentString({
+          action: "",
+          launchUrl: principaluri.hostPort,
+        }),
+        actions: Object.fromEntries(
+          [
+            parsedSnoozeAction(principaluri.hostPort),
+            parsedSettingsAction(principaluri.hostPort),
+            [
+              "dismissTitle",
+              {
+                content: "dismissTitle",
+                arguments: parsedArgumentString({
+                  action: "dismiss",
+                  launchUrl: principaluri.hostPort,
+                }),
+              },
+            ],
+            [
+              "snoozeTitle",
+              {
+                content: "snoozeTitle",
+                arguments: parsedArgumentString({
+                  action: "snooze",
+                  launchUrl: principaluri.hostPort,
+                }),
+              },
+            ],
+          ].filter(x => x.length)
+        ),
+      },
+    ],
+    parseLaunchAndActions(alertsService.getXmlStringForWindowsAlert(alert)),
+    when
+  );
+
+  // Chrome privileged alerts can set `opaqueRelaunchData`.
+  alert = makeAlert({
+    name,
+    title,
+    text,
+    imageURL,
+    principal: systemPrincipal,
+    opaqueRelaunchData: JSON.stringify(opaqueRelaunchData),
+  });
+  expected = `<toast launch="launch"><visual><binding template="ToastGeneric"><image id="1" src="file:///image.png"/><text id="1">title</text><text id="2">text</text></binding></visual><actions>${settingsAction}</actions></toast>`;
+  Assert.deepEqual(
+    [
+      expected.replace("<actions></actions>", "<actions/>"),
+      {
+        launch: parsedArgumentString({
+          action: "",
+          opaqueRelaunchData: JSON.stringify(opaqueRelaunchData),
+          privilegedName: name,
+        }),
+        actions: Object.fromEntries(
+          [parsedSettingsActionWithPrivilegedName].filter(x => x.length)
+        ),
+      },
+    ],
+    parseLaunchAndActions(alertsService.getXmlStringForWindowsAlert(alert)),
+    when
+  );
+
+  // But content unprivileged alerts can't set `opaqueRelaunchData`.
+  alert = makeAlert({
+    name,
+    title,
+    text,
+    imageURL,
+    principal,
+    opaqueRelaunchData: JSON.stringify(opaqueRelaunchData),
+  });
+  expected = `<toast launch="launch"><visual><binding template="ToastImageAndText04"><image id="1" src="file:///image.png"/><text id="1">title</text><text id="2">text</text><text id="3" placement="attribution">via example.com</text></binding></visual><actions><action content="Disable notifications from example.com"/>${settingsAction}</actions></toast>`;
+  Assert.deepEqual(
+    [
+      expected.replace("<actions></actions>", "<actions/>"),
+      {
+        launch: parsedArgumentString({
+          action: "",
+          launchUrl: principaluri.hostPort,
+        }),
+        actions: Object.fromEntries(
+          [
+            parsedSnoozeAction(principaluri.hostPort),
+            parsedSettingsAction(principaluri.hostPort),
+          ].filter(x => x.length)
+        ),
+      },
+    ],
+    parseLaunchAndActions(alertsService.getXmlStringForWindowsAlert(alert)),
+    when
+  );
+
+  // Chrome privileged alerts can set action-specific relaunch parameters.
+  let systemRelaunchActions = [
+    {
+      action: "action1",
+      title: "title1",
+      opaqueRelaunchData: JSON.stringify({ json: "data1" }),
+    },
+    {
+      action: "action2",
+      title: "title2",
+      opaqueRelaunchData: JSON.stringify({ json: "data2" }),
+    },
+  ];
+  systemPrincipal = Services.scriptSecurityManager.getSystemPrincipal();
+  alert = makeAlert({
+    name,
+    title,
+    text,
+    imageURL,
+    principal: systemPrincipal,
+    actions: systemRelaunchActions,
+  });
+  expected = `<toast launch="launch"><visual><binding template="ToastGeneric"><image id="1" src="file:///image.png"/><text id="1">title</text><text id="2">text</text></binding></visual><actions>${settingsAction}<action content="title1"/><action content="title2"/></actions></toast>`;
+  Assert.deepEqual(
+    [
+      expected.replace("<actions></actions>", "<actions/>"),
+      {
+        launch: parsedArgumentString({ action: "", privilegedName: name }),
+        actions: Object.fromEntries(
+          [
+            parsedSettingsActionWithPrivilegedName,
+            [
+              "title1",
+              {
+                content: "title1",
+                arguments: parsedArgumentString(
+                  {
+                    action: "action1",
+                    opaqueRelaunchData: JSON.stringify({ json: "data1" }),
+                    privilegedName: name,
+                  },
+                  null,
+                  name
+                ),
+              },
+            ],
+
+            [
+              "title2",
+              {
+                content: "title2",
+                arguments: parsedArgumentString(
+                  {
+                    action: "action2",
+                    opaqueRelaunchData: JSON.stringify({ json: "data2" }),
+                    privilegedName: name,
+                  },
+                  null,
+                  name
+                ),
+              },
+            ],
+          ].filter(x => x.length)
+        ),
+      },
+    ],
+    parseLaunchAndActions(alertsService.getXmlStringForWindowsAlert(alert)),
+    when
+  );
+}
+
+add_task(async () => {
+  Services.prefs.deleteBranch(
+    "alerts.useSystemBackend.windows.notificationserver.enabled"
+  );
+  testAlert("when notification server pref is unset", {
+    profD: gProfD,
+  });
+
+  Services.prefs.setBoolPref(
+    "alerts.useSystemBackend.windows.notificationserver.enabled",
+    false
+  );
+  testAlert("when notification server pref is false", { profD: gProfD });
+
+  Services.prefs.setBoolPref(
+    "alerts.useSystemBackend.windows.notificationserver.enabled",
+    true
+  );
+  testAlert("when notification server pref is true", {
+    serverEnabled: true,
+    profD: gProfD,
+  });
+});
+
+let condition = {
+  skip_if: () => !AppConstants.MOZ_BACKGROUNDTASKS,
+};
+
+add_task(condition, async () => {
+  const bts = Cc["@mozilla.org/backgroundtasks;1"]?.getService(
+    Ci.nsIBackgroundTasks
+  );
+
+  // Pretend that this is a background task.
+  bts.overrideBackgroundTaskNameForTesting("taskname");
+
+  Services.prefs.setBoolPref(
+    "alerts.useSystemBackend.windows.notificationserver.enabled",
+    true
+  );
+  testAlert(
+    "when notification server pref is true in background task, no default profile",
+    { serverEnabled: true, isBackgroundTaskMode: true }
+  );
+
+  let profileService = Cc["@mozilla.org/toolkit/profile-service;1"].getService(
+    Ci.nsIToolkitProfileService
+  );
+
+  let profilePath = do_get_profile();
+  profilePath.append(`test_windows_alert_service`);
+  let profile = profileService.createUniqueProfile(
+    profilePath,
+    "test_windows_alert_service"
+  );
+
+  profileService.defaultProfile = profile;
+
+  testAlert(
+    "when notification server pref is true in background task, default profile",
+    { serverEnabled: true, isBackgroundTaskMode: true, profD: profilePath }
+  );
+
+  // No longer a background task,
+  bts.overrideBackgroundTaskNameForTesting("");
+});
diff --git a/widget/windows/tests/unit/xpcshell.toml b/widget/windows/tests/unit/xpcshell.toml
new file mode 100644
index 0000000000..9943d5510e
--- /dev/null
+++ b/widget/windows/tests/unit/xpcshell.toml
@@ -0,0 +1,3 @@
+[DEFAULT]
+
+["test_windows_alert_service.js"]
diff --git a/widget/windows/touchinjection_sdk80.h b/widget/windows/touchinjection_sdk80.h
new file mode 100644
index 0000000000..7e9f5410d2
--- /dev/null
+++ b/widget/windows/touchinjection_sdk80.h
@@ -0,0 +1,171 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef touchinjection_sdk80_h
+#define touchinjection_sdk80_h
+
+#include <windows.h>
+
+// Note, this isn't inclusive of all touch injection header info.
+// You may need to add more to expand on current apis.
+
+#ifndef TOUCH_FEEDBACK_DEFAULT
+
+#  define TOUCH_FEEDBACK_DEFAULT 0x1
+#  define TOUCH_FEEDBACK_INDIRECT 0x2
+#  define TOUCH_FEEDBACK_NONE 0x3
+
+enum POINTER_FEEDBACK_MODE {
+  POINTER_FEEDBACK_DEFAULT =
+      1,  // The injected pointer input feedback may get suppressed by the
+          // end-user settings in the Pen and Touch control panel.
+  POINTER_FEEDBACK_INDIRECT =
+      2,  // The injected pointer input feedback overrides the end-user settings
+          // in the Pen and Touch control panel.
+  POINTER_FEEDBACK_NONE = 3,  // No touch visualizations.
+};
+
+enum {
+  PT_POINTER = 0x00000001,   // Generic pointer
+  PT_TOUCH = 0x00000002,     // Touch
+  PT_PEN = 0x00000003,       // Pen
+  PT_MOUSE = 0x00000004,     // Mouse
+  PT_TOUCHPAD = 0x00000005,  // Touch pad
+};
+
+using POINTER_INPUT_TYPE = DWORD;
+using POINTER_FLAGS = UINT32;
+
+enum POINTER_BUTTON_CHANGE_TYPE {
+  POINTER_CHANGE_NONE,
+  POINTER_CHANGE_FIRSTBUTTON_DOWN,
+  POINTER_CHANGE_FIRSTBUTTON_UP,
+  POINTER_CHANGE_SECONDBUTTON_DOWN,
+  POINTER_CHANGE_SECONDBUTTON_UP,
+  POINTER_CHANGE_THIRDBUTTON_DOWN,
+  POINTER_CHANGE_THIRDBUTTON_UP,
+  POINTER_CHANGE_FOURTHBUTTON_DOWN,
+  POINTER_CHANGE_FOURTHBUTTON_UP,
+  POINTER_CHANGE_FIFTHBUTTON_DOWN,
+  POINTER_CHANGE_FIFTHBUTTON_UP,
+};
+
+struct POINTER_INFO {
+  POINTER_INPUT_TYPE pointerType;
+  UINT32 pointerId;
+  UINT32 frameId;
+  POINTER_FLAGS pointerFlags;
+  HANDLE sourceDevice;
+  HWND hwndTarget;
+  POINT ptPixelLocation;
+  POINT ptHimetricLocation;
+  POINT ptPixelLocationRaw;
+  POINT ptHimetricLocationRaw;
+  DWORD dwTime;
+  UINT32 historyCount;
+  INT32 InputData;
+  DWORD dwKeyStates;
+  UINT64 PerformanceCount;
+  POINTER_BUTTON_CHANGE_TYPE ButtonChangeType;
+};
+
+using TOUCH_FLAGS = UINT32;
+using TOUCH_MASK = UINT32;
+
+struct POINTER_TOUCH_INFO {
+  POINTER_INFO pointerInfo;
+  TOUCH_FLAGS touchFlags;
+  TOUCH_MASK touchMask;
+  RECT rcContact;
+  RECT rcContactRaw;
+  UINT32 orientation;
+  UINT32 pressure;
+};
+
+#  define PEN_FLAG_NONE 0x00000000      // Default
+#  define PEN_FLAG_BARREL 0x00000001    // The barrel button is pressed
+#  define PEN_FLAG_INVERTED 0x00000002  // The pen is inverted
+#  define PEN_FLAG_ERASER 0x00000004    // The eraser button is pressed
+
+#  define PEN_MASK_NONE \
+    0x00000000  // Default - none of the optional fields are valid
+#  define PEN_MASK_PRESSURE 0x00000001  // The pressure field is valid
+#  define PEN_MASK_ROTATION 0x00000002  // The rotation field is valid
+#  define PEN_MASK_TILT_X 0x00000004    // The tiltX field is valid
+#  define PEN_MASK_TILT_Y 0x00000008    // The tiltY field is valid
+
+using PEN_FLAGS = UINT32;
+using PEN_MASK = UINT32;
+
+struct POINTER_PEN_INFO {
+  POINTER_INFO pointerInfo;
+  PEN_FLAGS penFlags;
+  PEN_MASK penMask;
+  UINT32 pressure;
+  UINT32 rotation;
+  INT32 tiltX;
+  INT32 tiltY;
+};
+
+struct POINTER_TYPE_INFO {
+  POINTER_INPUT_TYPE type;
+  union {
+    POINTER_TOUCH_INFO touchInfo;
+    POINTER_PEN_INFO penInfo;
+  };
+};
+
+#  define TOUCH_FLAG_NONE 0x00000000  // Default
+
+#  define TOUCH_MASK_NONE \
+    0x00000000  // Default - none of the optional fields are valid
+#  define TOUCH_MASK_CONTACTAREA 0x00000001  // The rcContact field is valid
+#  define TOUCH_MASK_ORIENTATION 0x00000002  // The orientation field is valid
+#  define TOUCH_MASK_PRESSURE 0x00000004     // The pressure field is valid
+
+#  define POINTER_FLAG_NONE 0x00000000          // Default
+#  define POINTER_FLAG_NEW 0x00000001           // New pointer
+#  define POINTER_FLAG_INRANGE 0x00000002       // Pointer has not departed
+#  define POINTER_FLAG_INCONTACT 0x00000004     // Pointer is in contact
+#  define POINTER_FLAG_FIRSTBUTTON 0x00000010   // Primary action
+#  define POINTER_FLAG_SECONDBUTTON 0x00000020  // Secondary action
+#  define POINTER_FLAG_THIRDBUTTON 0x00000040   // Third button
+#  define POINTER_FLAG_FOURTHBUTTON 0x00000080  // Fourth button
+#  define POINTER_FLAG_FIFTHBUTTON 0x00000100   // Fifth button
+#  define POINTER_FLAG_PRIMARY 0x00002000       // Pointer is primary
+#  define POINTER_FLAG_CONFIDENCE \
+    0x00004000  // Pointer is considered unlikely to be accidental
+#  define POINTER_FLAG_CANCELED \
+    0x00008000  // Pointer is departing in an abnormal manner
+#  define POINTER_FLAG_DOWN \
+    0x00010000  // Pointer transitioned to down state (made contact)
+#  define POINTER_FLAG_UPDATE 0x00020000  // Pointer update
+#  define POINTER_FLAG_UP \
+    0x00040000  // Pointer transitioned from down state (broke contact)
+#  define POINTER_FLAG_WHEEL 0x00080000           // Vertical wheel
+#  define POINTER_FLAG_HWHEEL 0x00100000          // Horizontal wheel
+#  define POINTER_FLAG_CAPTURECHANGED 0x00200000  // Lost capture
+
+#endif  // TOUCH_FEEDBACK_DEFAULT
+
+#define TOUCH_FLAGS_CONTACTUPDATE \
+  (POINTER_FLAG_UPDATE | POINTER_FLAG_INRANGE | POINTER_FLAG_INCONTACT)
+#define TOUCH_FLAGS_CONTACTDOWN \
+  (POINTER_FLAG_DOWN | POINTER_FLAG_INRANGE | POINTER_FLAG_INCONTACT)
+
+using InitializeTouchInjectionPtr = BOOL(WINAPI*)(UINT32, DWORD);
+using InjectTouchInputPtr = BOOL(WINAPI*)(UINT32, const POINTER_TOUCH_INFO*);
+
+#if !defined(NTDDI_WIN10_RS5) || (NTDDI_VERSION < NTDDI_WIN10_RS5)
+#  define HSYNTHETICPOINTERDEVICE intptr_t
+#endif  // NTDDI_VERSION < NTDDI_WIN10_RS5
+
+using CreateSyntheticPointerDevicePtr = HSYNTHETICPOINTERDEVICE(WINAPI*)(
+    POINTER_INPUT_TYPE, ULONG, POINTER_FEEDBACK_MODE);
+using DestroySyntheticPointerDevicePtr = void(WINAPI*)(HSYNTHETICPOINTERDEVICE);
+using InjectSyntheticPointerInputPtr = BOOL(WINAPI*)(HSYNTHETICPOINTERDEVICE,
+                                                     const POINTER_TYPE_INFO*,
+                                                     UINT32);
+
+#endif  // touchinjection_sdk80_h
diff --git a/widget/windows/widget.rc b/widget/windows/widget.rc
new file mode 100644
index 0000000000..9361f9e48c
--- /dev/null
+++ b/widget/windows/widget.rc
@@ -0,0 +1,30 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "resource.h"
+#include <winresrc.h>
+#include <dlgs.h>
+
+IDC_GRAB                CURSOR  DISCARDABLE     "res/grab.cur"
+IDC_GRABBING            CURSOR  DISCARDABLE     "res/grabbing.cur"
+IDC_CELL                CURSOR  DISCARDABLE     "res/cell.cur"
+IDC_COPY                CURSOR  DISCARDABLE     "res/copy.cur"
+IDC_ALIAS               CURSOR  DISCARDABLE     "res/aliasb.cur"
+IDC_ZOOMIN              CURSOR  DISCARDABLE     "res/zoom_in.cur"
+IDC_ZOOMOUT             CURSOR  DISCARDABLE     "res/zoom_out.cur"
+IDC_COLRESIZE           CURSOR  DISCARDABLE     "res/col_resize.cur"
+IDC_ROWRESIZE           CURSOR  DISCARDABLE     "res/row_resize.cur"
+IDC_VERTICALTEXT        CURSOR  DISCARDABLE     "res/vertical_text.cur"
+IDC_NONE                CURSOR  DISCARDABLE     "res/none.cur"
+
+OPTPROPSHEET DIALOG DISCARDABLE  32, 32, 288, 226
+STYLE DS_MODALFRAME | DS_3DLOOK | DS_CONTEXTHELP | WS_POPUP | WS_VISIBLE | 
+    WS_CAPTION | WS_SYSMENU
+CAPTION "Options"
+FONT 8, "MS Sans Serif"
+BEGIN
+
+END
diff --git a/widget/x11/keysym2ucs.c b/widget/x11/keysym2ucs.c
new file mode 100644
index 0000000000..b0c2229e6d
--- /dev/null
+++ b/widget/x11/keysym2ucs.c
@@ -0,0 +1,866 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/*
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+/*
+ * This module converts keysym values into the corresponding ISO 10646-1
+ * (UCS, Unicode) values.
+ *
+ * The array keysymtab[] contains pairs of X11 keysym values for graphical
+ * characters and the corresponding Unicode value. The function
+ * keysym2ucs() maps a keysym onto a Unicode value using a binary search,
+ * therefore keysymtab[] must remain SORTED by keysym value.
+ *
+ * The keysym -> UTF-8 conversion will hopefully one day be provided
+ * by Xlib via XmbLookupString() and should ideally not have to be
+ * done in X applications. But we are not there yet.
+ *
+ * We allow to represent any UCS character in the range U+00000000 to
+ * U+00FFFFFF by a keysym value in the range 0x01000000 to 0x01ffffff.
+ * This admittedly does not cover the entire 31-bit space of UCS, but
+ * it does cover all of the characters up to U+10FFFF, which can be
+ * represented by UTF-16, and more, and it is very unlikely that higher
+ * UCS codes will ever be assigned by ISO. So to get Unicode character
+ * U+ABCD you can directly use keysym 0x1000abcd.
+ *
+ * NOTE: The comments in the table below contain the actual character
+ * encoded in UTF-8, so for viewing and editing best use an editor in
+ * UTF-8 mode.
+ *
+ * Author: Markus G. Kuhn <mkuhn@acm.org>, University of Cambridge, June 1999
+ *
+ * Special thanks to Richard Verhoeven <river@win.tue.nl> for preparing
+ * an initial draft of the mapping table.
+ *
+ * This software is in the public domain. Share and enjoy!
+ */
+
+#include "keysym2ucs.h"
+
+static const struct codepair {
+  unsigned short keysym;
+  unsigned short ucs;
+} keysymtab[] = {
+    // clang-format off
+  { 0x01a1, 0x0104 }, /*                     Aogonek Ą LATIN CAPITAL LETTER A WITH OGONEK */
+  { 0x01a2, 0x02d8 }, /*                       breve ˘ BREVE */
+  { 0x01a3, 0x0141 }, /*                     Lstroke Ł LATIN CAPITAL LETTER L WITH STROKE */
+  { 0x01a5, 0x013d }, /*                      Lcaron Ľ LATIN CAPITAL LETTER L WITH CARON */
+  { 0x01a6, 0x015a }, /*                      Sacute Ś LATIN CAPITAL LETTER S WITH ACUTE */
+  { 0x01a9, 0x0160 }, /*                      Scaron Š LATIN CAPITAL LETTER S WITH CARON */
+  { 0x01aa, 0x015e }, /*                    Scedilla Ş LATIN CAPITAL LETTER S WITH CEDILLA */
+  { 0x01ab, 0x0164 }, /*                      Tcaron Ť LATIN CAPITAL LETTER T WITH CARON */
+  { 0x01ac, 0x0179 }, /*                      Zacute Ź LATIN CAPITAL LETTER Z WITH ACUTE */
+  { 0x01ae, 0x017d }, /*                      Zcaron Ž LATIN CAPITAL LETTER Z WITH CARON */
+  { 0x01af, 0x017b }, /*                   Zabovedot Ż LATIN CAPITAL LETTER Z WITH DOT ABOVE */
+  { 0x01b1, 0x0105 }, /*                     aogonek ą LATIN SMALL LETTER A WITH OGONEK */
+  { 0x01b2, 0x02db }, /*                      ogonek ˛ OGONEK */
+  { 0x01b3, 0x0142 }, /*                     lstroke ł LATIN SMALL LETTER L WITH STROKE */
+  { 0x01b5, 0x013e }, /*                      lcaron ľ LATIN SMALL LETTER L WITH CARON */
+  { 0x01b6, 0x015b }, /*                      sacute ś LATIN SMALL LETTER S WITH ACUTE */
+  { 0x01b7, 0x02c7 }, /*                       caron ˇ CARON */
+  { 0x01b9, 0x0161 }, /*                      scaron š LATIN SMALL LETTER S WITH CARON */
+  { 0x01ba, 0x015f }, /*                    scedilla ş LATIN SMALL LETTER S WITH CEDILLA */
+  { 0x01bb, 0x0165 }, /*                      tcaron ť LATIN SMALL LETTER T WITH CARON */
+  { 0x01bc, 0x017a }, /*                      zacute ź LATIN SMALL LETTER Z WITH ACUTE */
+  { 0x01bd, 0x02dd }, /*                 doubleacute ˝ DOUBLE ACUTE ACCENT */
+  { 0x01be, 0x017e }, /*                      zcaron ž LATIN SMALL LETTER Z WITH CARON */
+  { 0x01bf, 0x017c }, /*                   zabovedot ż LATIN SMALL LETTER Z WITH DOT ABOVE */
+  { 0x01c0, 0x0154 }, /*                      Racute Ŕ LATIN CAPITAL LETTER R WITH ACUTE */
+  { 0x01c3, 0x0102 }, /*                      Abreve Ă LATIN CAPITAL LETTER A WITH BREVE */
+  { 0x01c5, 0x0139 }, /*                      Lacute Ĺ LATIN CAPITAL LETTER L WITH ACUTE */
+  { 0x01c6, 0x0106 }, /*                      Cacute Ć LATIN CAPITAL LETTER C WITH ACUTE */
+  { 0x01c8, 0x010c }, /*                      Ccaron Č LATIN CAPITAL LETTER C WITH CARON */
+  { 0x01ca, 0x0118 }, /*                     Eogonek Ę LATIN CAPITAL LETTER E WITH OGONEK */
+  { 0x01cc, 0x011a }, /*                      Ecaron Ě LATIN CAPITAL LETTER E WITH CARON */
+  { 0x01cf, 0x010e }, /*                      Dcaron Ď LATIN CAPITAL LETTER D WITH CARON */
+  { 0x01d0, 0x0110 }, /*                     Dstroke Đ LATIN CAPITAL LETTER D WITH STROKE */
+  { 0x01d1, 0x0143 }, /*                      Nacute Ń LATIN CAPITAL LETTER N WITH ACUTE */
+  { 0x01d2, 0x0147 }, /*                      Ncaron Ň LATIN CAPITAL LETTER N WITH CARON */
+  { 0x01d5, 0x0150 }, /*                Odoubleacute Ő LATIN CAPITAL LETTER O WITH DOUBLE ACUTE */
+  { 0x01d8, 0x0158 }, /*                      Rcaron Ř LATIN CAPITAL LETTER R WITH CARON */
+  { 0x01d9, 0x016e }, /*                       Uring Ů LATIN CAPITAL LETTER U WITH RING ABOVE */
+  { 0x01db, 0x0170 }, /*                Udoubleacute Ű LATIN CAPITAL LETTER U WITH DOUBLE ACUTE */
+  { 0x01de, 0x0162 }, /*                    Tcedilla Ţ LATIN CAPITAL LETTER T WITH CEDILLA */
+  { 0x01e0, 0x0155 }, /*                      racute ŕ LATIN SMALL LETTER R WITH ACUTE */
+  { 0x01e3, 0x0103 }, /*                      abreve ă LATIN SMALL LETTER A WITH BREVE */
+  { 0x01e5, 0x013a }, /*                      lacute ĺ LATIN SMALL LETTER L WITH ACUTE */
+  { 0x01e6, 0x0107 }, /*                      cacute ć LATIN SMALL LETTER C WITH ACUTE */
+  { 0x01e8, 0x010d }, /*                      ccaron č LATIN SMALL LETTER C WITH CARON */
+  { 0x01ea, 0x0119 }, /*                     eogonek ę LATIN SMALL LETTER E WITH OGONEK */
+  { 0x01ec, 0x011b }, /*                      ecaron ě LATIN SMALL LETTER E WITH CARON */
+  { 0x01ef, 0x010f }, /*                      dcaron ď LATIN SMALL LETTER D WITH CARON */
+  { 0x01f0, 0x0111 }, /*                     dstroke đ LATIN SMALL LETTER D WITH STROKE */
+  { 0x01f1, 0x0144 }, /*                      nacute ń LATIN SMALL LETTER N WITH ACUTE */
+  { 0x01f2, 0x0148 }, /*                      ncaron ň LATIN SMALL LETTER N WITH CARON */
+  { 0x01f5, 0x0151 }, /*                odoubleacute ő LATIN SMALL LETTER O WITH DOUBLE ACUTE */
+  { 0x01f8, 0x0159 }, /*                      rcaron ř LATIN SMALL LETTER R WITH CARON */
+  { 0x01f9, 0x016f }, /*                       uring ů LATIN SMALL LETTER U WITH RING ABOVE */
+  { 0x01fb, 0x0171 }, /*                udoubleacute ű LATIN SMALL LETTER U WITH DOUBLE ACUTE */
+  { 0x01fe, 0x0163 }, /*                    tcedilla ţ LATIN SMALL LETTER T WITH CEDILLA */
+  { 0x01ff, 0x02d9 }, /*                    abovedot ˙ DOT ABOVE */
+  { 0x02a1, 0x0126 }, /*                     Hstroke Ħ LATIN CAPITAL LETTER H WITH STROKE */
+  { 0x02a6, 0x0124 }, /*                 Hcircumflex Ĥ LATIN CAPITAL LETTER H WITH CIRCUMFLEX */
+  { 0x02a9, 0x0130 }, /*                   Iabovedot İ LATIN CAPITAL LETTER I WITH DOT ABOVE */
+  { 0x02ab, 0x011e }, /*                      Gbreve Ğ LATIN CAPITAL LETTER G WITH BREVE */
+  { 0x02ac, 0x0134 }, /*                 Jcircumflex Ĵ LATIN CAPITAL LETTER J WITH CIRCUMFLEX */
+  { 0x02b1, 0x0127 }, /*                     hstroke ħ LATIN SMALL LETTER H WITH STROKE */
+  { 0x02b6, 0x0125 }, /*                 hcircumflex ĥ LATIN SMALL LETTER H WITH CIRCUMFLEX */
+  { 0x02b9, 0x0131 }, /*                    idotless ı LATIN SMALL LETTER DOTLESS I */
+  { 0x02bb, 0x011f }, /*                      gbreve ğ LATIN SMALL LETTER G WITH BREVE */
+  { 0x02bc, 0x0135 }, /*                 jcircumflex ĵ LATIN SMALL LETTER J WITH CIRCUMFLEX */
+  { 0x02c5, 0x010a }, /*                   Cabovedot Ċ LATIN CAPITAL LETTER C WITH DOT ABOVE */
+  { 0x02c6, 0x0108 }, /*                 Ccircumflex Ĉ LATIN CAPITAL LETTER C WITH CIRCUMFLEX */
+  { 0x02d5, 0x0120 }, /*                   Gabovedot Ġ LATIN CAPITAL LETTER G WITH DOT ABOVE */
+  { 0x02d8, 0x011c }, /*                 Gcircumflex Ĝ LATIN CAPITAL LETTER G WITH CIRCUMFLEX */
+  { 0x02dd, 0x016c }, /*                      Ubreve Ŭ LATIN CAPITAL LETTER U WITH BREVE */
+  { 0x02de, 0x015c }, /*                 Scircumflex Ŝ LATIN CAPITAL LETTER S WITH CIRCUMFLEX */
+  { 0x02e5, 0x010b }, /*                   cabovedot ċ LATIN SMALL LETTER C WITH DOT ABOVE */
+  { 0x02e6, 0x0109 }, /*                 ccircumflex ĉ LATIN SMALL LETTER C WITH CIRCUMFLEX */
+  { 0x02f5, 0x0121 }, /*                   gabovedot ġ LATIN SMALL LETTER G WITH DOT ABOVE */
+  { 0x02f8, 0x011d }, /*                 gcircumflex ĝ LATIN SMALL LETTER G WITH CIRCUMFLEX */
+  { 0x02fd, 0x016d }, /*                      ubreve ŭ LATIN SMALL LETTER U WITH BREVE */
+  { 0x02fe, 0x015d }, /*                 scircumflex ŝ LATIN SMALL LETTER S WITH CIRCUMFLEX */
+  { 0x03a2, 0x0138 }, /*                         kra ĸ LATIN SMALL LETTER KRA */
+  { 0x03a3, 0x0156 }, /*                    Rcedilla Ŗ LATIN CAPITAL LETTER R WITH CEDILLA */
+  { 0x03a5, 0x0128 }, /*                      Itilde Ĩ LATIN CAPITAL LETTER I WITH TILDE */
+  { 0x03a6, 0x013b }, /*                    Lcedilla Ļ LATIN CAPITAL LETTER L WITH CEDILLA */
+  { 0x03aa, 0x0112 }, /*                     Emacron Ē LATIN CAPITAL LETTER E WITH MACRON */
+  { 0x03ab, 0x0122 }, /*                    Gcedilla Ģ LATIN CAPITAL LETTER G WITH CEDILLA */
+  { 0x03ac, 0x0166 }, /*                      Tslash Ŧ LATIN CAPITAL LETTER T WITH STROKE */
+  { 0x03b3, 0x0157 }, /*                    rcedilla ŗ LATIN SMALL LETTER R WITH CEDILLA */
+  { 0x03b5, 0x0129 }, /*                      itilde ĩ LATIN SMALL LETTER I WITH TILDE */
+  { 0x03b6, 0x013c }, /*                    lcedilla ļ LATIN SMALL LETTER L WITH CEDILLA */
+  { 0x03ba, 0x0113 }, /*                     emacron ē LATIN SMALL LETTER E WITH MACRON */
+  { 0x03bb, 0x0123 }, /*                    gcedilla ģ LATIN SMALL LETTER G WITH CEDILLA */
+  { 0x03bc, 0x0167 }, /*                      tslash ŧ LATIN SMALL LETTER T WITH STROKE */
+  { 0x03bd, 0x014a }, /*                         ENG Ŋ LATIN CAPITAL LETTER ENG */
+  { 0x03bf, 0x014b }, /*                         eng ŋ LATIN SMALL LETTER ENG */
+  { 0x03c0, 0x0100 }, /*                     Amacron Ā LATIN CAPITAL LETTER A WITH MACRON */
+  { 0x03c7, 0x012e }, /*                     Iogonek Į LATIN CAPITAL LETTER I WITH OGONEK */
+  { 0x03cc, 0x0116 }, /*                   Eabovedot Ė LATIN CAPITAL LETTER E WITH DOT ABOVE */
+  { 0x03cf, 0x012a }, /*                     Imacron Ī LATIN CAPITAL LETTER I WITH MACRON */
+  { 0x03d1, 0x0145 }, /*                    Ncedilla Ņ LATIN CAPITAL LETTER N WITH CEDILLA */
+  { 0x03d2, 0x014c }, /*                     Omacron Ō LATIN CAPITAL LETTER O WITH MACRON */
+  { 0x03d3, 0x0136 }, /*                    Kcedilla Ķ LATIN CAPITAL LETTER K WITH CEDILLA */
+  { 0x03d9, 0x0172 }, /*                     Uogonek Ų LATIN CAPITAL LETTER U WITH OGONEK */
+  { 0x03dd, 0x0168 }, /*                      Utilde Ũ LATIN CAPITAL LETTER U WITH TILDE */
+  { 0x03de, 0x016a }, /*                     Umacron Ū LATIN CAPITAL LETTER U WITH MACRON */
+  { 0x03e0, 0x0101 }, /*                     amacron ā LATIN SMALL LETTER A WITH MACRON */
+  { 0x03e7, 0x012f }, /*                     iogonek į LATIN SMALL LETTER I WITH OGONEK */
+  { 0x03ec, 0x0117 }, /*                   eabovedot ė LATIN SMALL LETTER E WITH DOT ABOVE */
+  { 0x03ef, 0x012b }, /*                     imacron ī LATIN SMALL LETTER I WITH MACRON */
+  { 0x03f1, 0x0146 }, /*                    ncedilla ņ LATIN SMALL LETTER N WITH CEDILLA */
+  { 0x03f2, 0x014d }, /*                     omacron ō LATIN SMALL LETTER O WITH MACRON */
+  { 0x03f3, 0x0137 }, /*                    kcedilla ķ LATIN SMALL LETTER K WITH CEDILLA */
+  { 0x03f9, 0x0173 }, /*                     uogonek ų LATIN SMALL LETTER U WITH OGONEK */
+  { 0x03fd, 0x0169 }, /*                      utilde ũ LATIN SMALL LETTER U WITH TILDE */
+  { 0x03fe, 0x016b }, /*                     umacron ū LATIN SMALL LETTER U WITH MACRON */
+  { 0x047e, 0x203e }, /*                    overline ‾ OVERLINE */
+  { 0x04a1, 0x3002 }, /*               kana_fullstop 。 IDEOGRAPHIC FULL STOP */
+  { 0x04a2, 0x300c }, /*         kana_openingbracket 「 LEFT CORNER BRACKET */
+  { 0x04a3, 0x300d }, /*         kana_closingbracket 」 RIGHT CORNER BRACKET */
+  { 0x04a4, 0x3001 }, /*                  kana_comma 、 IDEOGRAPHIC COMMA */
+  { 0x04a5, 0x30fb }, /*            kana_conjunctive ・ KATAKANA MIDDLE DOT */
+  { 0x04a6, 0x30f2 }, /*                     kana_WO ヲ KATAKANA LETTER WO */
+  { 0x04a7, 0x30a1 }, /*                      kana_a ァ KATAKANA LETTER SMALL A */
+  { 0x04a8, 0x30a3 }, /*                      kana_i ィ KATAKANA LETTER SMALL I */
+  { 0x04a9, 0x30a5 }, /*                      kana_u ゥ KATAKANA LETTER SMALL U */
+  { 0x04aa, 0x30a7 }, /*                      kana_e ェ KATAKANA LETTER SMALL E */
+  { 0x04ab, 0x30a9 }, /*                      kana_o ォ KATAKANA LETTER SMALL O */
+  { 0x04ac, 0x30e3 }, /*                     kana_ya ャ KATAKANA LETTER SMALL YA */
+  { 0x04ad, 0x30e5 }, /*                     kana_yu ュ KATAKANA LETTER SMALL YU */
+  { 0x04ae, 0x30e7 }, /*                     kana_yo ョ KATAKANA LETTER SMALL YO */
+  { 0x04af, 0x30c3 }, /*                    kana_tsu ッ KATAKANA LETTER SMALL TU */
+  { 0x04b0, 0x30fc }, /*              prolongedsound ー KATAKANA-HIRAGANA PROLONGED SOUND MARK */
+  { 0x04b1, 0x30a2 }, /*                      kana_A ア KATAKANA LETTER A */
+  { 0x04b2, 0x30a4 }, /*                      kana_I イ KATAKANA LETTER I */
+  { 0x04b3, 0x30a6 }, /*                      kana_U ウ KATAKANA LETTER U */
+  { 0x04b4, 0x30a8 }, /*                      kana_E エ KATAKANA LETTER E */
+  { 0x04b5, 0x30aa }, /*                      kana_O オ KATAKANA LETTER O */
+  { 0x04b6, 0x30ab }, /*                     kana_KA カ KATAKANA LETTER KA */
+  { 0x04b7, 0x30ad }, /*                     kana_KI キ KATAKANA LETTER KI */
+  { 0x04b8, 0x30af }, /*                     kana_KU ク KATAKANA LETTER KU */
+  { 0x04b9, 0x30b1 }, /*                     kana_KE ケ KATAKANA LETTER KE */
+  { 0x04ba, 0x30b3 }, /*                     kana_KO コ KATAKANA LETTER KO */
+  { 0x04bb, 0x30b5 }, /*                     kana_SA サ KATAKANA LETTER SA */
+  { 0x04bc, 0x30b7 }, /*                    kana_SHI シ KATAKANA LETTER SI */
+  { 0x04bd, 0x30b9 }, /*                     kana_SU ス KATAKANA LETTER SU */
+  { 0x04be, 0x30bb }, /*                     kana_SE セ KATAKANA LETTER SE */
+  { 0x04bf, 0x30bd }, /*                     kana_SO ソ KATAKANA LETTER SO */
+  { 0x04c0, 0x30bf }, /*                     kana_TA タ KATAKANA LETTER TA */
+  { 0x04c1, 0x30c1 }, /*                    kana_CHI チ KATAKANA LETTER TI */
+  { 0x04c2, 0x30c4 }, /*                    kana_TSU ツ KATAKANA LETTER TU */
+  { 0x04c3, 0x30c6 }, /*                     kana_TE テ KATAKANA LETTER TE */
+  { 0x04c4, 0x30c8 }, /*                     kana_TO ト KATAKANA LETTER TO */
+  { 0x04c5, 0x30ca }, /*                     kana_NA ナ KATAKANA LETTER NA */
+  { 0x04c6, 0x30cb }, /*                     kana_NI ニ KATAKANA LETTER NI */
+  { 0x04c7, 0x30cc }, /*                     kana_NU ヌ KATAKANA LETTER NU */
+  { 0x04c8, 0x30cd }, /*                     kana_NE ネ KATAKANA LETTER NE */
+  { 0x04c9, 0x30ce }, /*                     kana_NO ノ KATAKANA LETTER NO */
+  { 0x04ca, 0x30cf }, /*                     kana_HA ハ KATAKANA LETTER HA */
+  { 0x04cb, 0x30d2 }, /*                     kana_HI ヒ KATAKANA LETTER HI */
+  { 0x04cc, 0x30d5 }, /*                     kana_FU フ KATAKANA LETTER HU */
+  { 0x04cd, 0x30d8 }, /*                     kana_HE ヘ KATAKANA LETTER HE */
+  { 0x04ce, 0x30db }, /*                     kana_HO ホ KATAKANA LETTER HO */
+  { 0x04cf, 0x30de }, /*                     kana_MA マ KATAKANA LETTER MA */
+  { 0x04d0, 0x30df }, /*                     kana_MI ミ KATAKANA LETTER MI */
+  { 0x04d1, 0x30e0 }, /*                     kana_MU ム KATAKANA LETTER MU */
+  { 0x04d2, 0x30e1 }, /*                     kana_ME メ KATAKANA LETTER ME */
+  { 0x04d3, 0x30e2 }, /*                     kana_MO モ KATAKANA LETTER MO */
+  { 0x04d4, 0x30e4 }, /*                     kana_YA ヤ KATAKANA LETTER YA */
+  { 0x04d5, 0x30e6 }, /*                     kana_YU ユ KATAKANA LETTER YU */
+  { 0x04d6, 0x30e8 }, /*                     kana_YO ヨ KATAKANA LETTER YO */
+  { 0x04d7, 0x30e9 }, /*                     kana_RA ラ KATAKANA LETTER RA */
+  { 0x04d8, 0x30ea }, /*                     kana_RI リ KATAKANA LETTER RI */
+  { 0x04d9, 0x30eb }, /*                     kana_RU ル KATAKANA LETTER RU */
+  { 0x04da, 0x30ec }, /*                     kana_RE レ KATAKANA LETTER RE */
+  { 0x04db, 0x30ed }, /*                     kana_RO ロ KATAKANA LETTER RO */
+  { 0x04dc, 0x30ef }, /*                     kana_WA ワ KATAKANA LETTER WA */
+  { 0x04dd, 0x30f3 }, /*                      kana_N ン KATAKANA LETTER N */
+  { 0x04de, 0x309b }, /*                 voicedsound ゛ KATAKANA-HIRAGANA VOICED SOUND MARK */
+  { 0x04df, 0x309c }, /*             semivoicedsound ゜ KATAKANA-HIRAGANA SEMI-VOICED SOUND MARK */
+  { 0x05ac, 0x060c }, /*                Arabic_comma ، ARABIC COMMA */
+  { 0x05bb, 0x061b }, /*            Arabic_semicolon ؛ ARABIC SEMICOLON */
+  { 0x05bf, 0x061f }, /*        Arabic_question_mark ؟ ARABIC QUESTION MARK */
+  { 0x05c1, 0x0621 }, /*                Arabic_hamza ء ARABIC LETTER HAMZA */
+  { 0x05c2, 0x0622 }, /*          Arabic_maddaonalef آ ARABIC LETTER ALEF WITH MADDA ABOVE */
+  { 0x05c3, 0x0623 }, /*          Arabic_hamzaonalef أ ARABIC LETTER ALEF WITH HAMZA ABOVE */
+  { 0x05c4, 0x0624 }, /*           Arabic_hamzaonwaw ؤ ARABIC LETTER WAW WITH HAMZA ABOVE */
+  { 0x05c5, 0x0625 }, /*       Arabic_hamzaunderalef إ ARABIC LETTER ALEF WITH HAMZA BELOW */
+  { 0x05c6, 0x0626 }, /*           Arabic_hamzaonyeh ئ ARABIC LETTER YEH WITH HAMZA ABOVE */
+  { 0x05c7, 0x0627 }, /*                 Arabic_alef ا ARABIC LETTER ALEF */
+  { 0x05c8, 0x0628 }, /*                  Arabic_beh ب ARABIC LETTER BEH */
+  { 0x05c9, 0x0629 }, /*           Arabic_tehmarbuta ة ARABIC LETTER TEH MARBUTA */
+  { 0x05ca, 0x062a }, /*                  Arabic_teh ت ARABIC LETTER TEH */
+  { 0x05cb, 0x062b }, /*                 Arabic_theh ث ARABIC LETTER THEH */
+  { 0x05cc, 0x062c }, /*                 Arabic_jeem ج ARABIC LETTER JEEM */
+  { 0x05cd, 0x062d }, /*                  Arabic_hah ح ARABIC LETTER HAH */
+  { 0x05ce, 0x062e }, /*                 Arabic_khah خ ARABIC LETTER KHAH */
+  { 0x05cf, 0x062f }, /*                  Arabic_dal د ARABIC LETTER DAL */
+  { 0x05d0, 0x0630 }, /*                 Arabic_thal ذ ARABIC LETTER THAL */
+  { 0x05d1, 0x0631 }, /*                   Arabic_ra ر ARABIC LETTER REH */
+  { 0x05d2, 0x0632 }, /*                 Arabic_zain ز ARABIC LETTER ZAIN */
+  { 0x05d3, 0x0633 }, /*                 Arabic_seen س ARABIC LETTER SEEN */
+  { 0x05d4, 0x0634 }, /*                Arabic_sheen ش ARABIC LETTER SHEEN */
+  { 0x05d5, 0x0635 }, /*                  Arabic_sad ص ARABIC LETTER SAD */
+  { 0x05d6, 0x0636 }, /*                  Arabic_dad ض ARABIC LETTER DAD */
+  { 0x05d7, 0x0637 }, /*                  Arabic_tah ط ARABIC LETTER TAH */
+  { 0x05d8, 0x0638 }, /*                  Arabic_zah ظ ARABIC LETTER ZAH */
+  { 0x05d9, 0x0639 }, /*                  Arabic_ain ع ARABIC LETTER AIN */
+  { 0x05da, 0x063a }, /*                Arabic_ghain غ ARABIC LETTER GHAIN */
+  { 0x05e0, 0x0640 }, /*              Arabic_tatweel ـ ARABIC TATWEEL */
+  { 0x05e1, 0x0641 }, /*                  Arabic_feh ف ARABIC LETTER FEH */
+  { 0x05e2, 0x0642 }, /*                  Arabic_qaf ق ARABIC LETTER QAF */
+  { 0x05e3, 0x0643 }, /*                  Arabic_kaf ك ARABIC LETTER KAF */
+  { 0x05e4, 0x0644 }, /*                  Arabic_lam ل ARABIC LETTER LAM */
+  { 0x05e5, 0x0645 }, /*                 Arabic_meem م ARABIC LETTER MEEM */
+  { 0x05e6, 0x0646 }, /*                 Arabic_noon ن ARABIC LETTER NOON */
+  { 0x05e7, 0x0647 }, /*                   Arabic_ha ه ARABIC LETTER HEH */
+  { 0x05e8, 0x0648 }, /*                  Arabic_waw و ARABIC LETTER WAW */
+  { 0x05e9, 0x0649 }, /*          Arabic_alefmaksura ى ARABIC LETTER ALEF MAKSURA */
+  { 0x05ea, 0x064a }, /*                  Arabic_yeh ي ARABIC LETTER YEH */
+  { 0x05eb, 0x064b }, /*             Arabic_fathatan ً ARABIC FATHATAN */
+  { 0x05ec, 0x064c }, /*             Arabic_dammatan ٌ ARABIC DAMMATAN */
+  { 0x05ed, 0x064d }, /*             Arabic_kasratan ٍ ARABIC KASRATAN */
+  { 0x05ee, 0x064e }, /*                Arabic_fatha َ ARABIC FATHA */
+  { 0x05ef, 0x064f }, /*                Arabic_damma ُ ARABIC DAMMA */
+  { 0x05f0, 0x0650 }, /*                Arabic_kasra ِ ARABIC KASRA */
+  { 0x05f1, 0x0651 }, /*               Arabic_shadda ّ ARABIC SHADDA */
+  { 0x05f2, 0x0652 }, /*                Arabic_sukun ْ ARABIC SUKUN */
+  { 0x06a1, 0x0452 }, /*                 Serbian_dje ђ CYRILLIC SMALL LETTER DJE */
+  { 0x06a2, 0x0453 }, /*               Macedonia_gje ѓ CYRILLIC SMALL LETTER GJE */
+  { 0x06a3, 0x0451 }, /*                 Cyrillic_io ё CYRILLIC SMALL LETTER IO */
+  { 0x06a4, 0x0454 }, /*                Ukrainian_ie є CYRILLIC SMALL LETTER UKRAINIAN IE */
+  { 0x06a5, 0x0455 }, /*               Macedonia_dse ѕ CYRILLIC SMALL LETTER DZE */
+  { 0x06a6, 0x0456 }, /*                 Ukrainian_i і CYRILLIC SMALL LETTER BYELORUSSIAN-UKRAINIAN I */
+  { 0x06a7, 0x0457 }, /*                Ukrainian_yi ї CYRILLIC SMALL LETTER YI */
+  { 0x06a8, 0x0458 }, /*                 Cyrillic_je ј CYRILLIC SMALL LETTER JE */
+  { 0x06a9, 0x0459 }, /*                Cyrillic_lje љ CYRILLIC SMALL LETTER LJE */
+  { 0x06aa, 0x045a }, /*                Cyrillic_nje њ CYRILLIC SMALL LETTER NJE */
+  { 0x06ab, 0x045b }, /*                Serbian_tshe ћ CYRILLIC SMALL LETTER TSHE */
+  { 0x06ac, 0x045c }, /*               Macedonia_kje ќ CYRILLIC SMALL LETTER KJE */
+  { 0x06ad, 0x0491 }, /*   Ukrainian_ghe_with_upturn ґ CYRILLIC SMALL LETTER GHE WITH UPTURN */
+  { 0x06ae, 0x045e }, /*         Byelorussian_shortu ў CYRILLIC SMALL LETTER SHORT U */
+  { 0x06af, 0x045f }, /*               Cyrillic_dzhe џ CYRILLIC SMALL LETTER DZHE */
+  { 0x06b0, 0x2116 }, /*                  numerosign № NUMERO SIGN */
+  { 0x06b1, 0x0402 }, /*                 Serbian_DJE Ђ CYRILLIC CAPITAL LETTER DJE */
+  { 0x06b2, 0x0403 }, /*               Macedonia_GJE Ѓ CYRILLIC CAPITAL LETTER GJE */
+  { 0x06b3, 0x0401 }, /*                 Cyrillic_IO Ё CYRILLIC CAPITAL LETTER IO */
+  { 0x06b4, 0x0404 }, /*                Ukrainian_IE Є CYRILLIC CAPITAL LETTER UKRAINIAN IE */
+  { 0x06b5, 0x0405 }, /*               Macedonia_DSE Ѕ CYRILLIC CAPITAL LETTER DZE */
+  { 0x06b6, 0x0406 }, /*                 Ukrainian_I І CYRILLIC CAPITAL LETTER BYELORUSSIAN-UKRAINIAN I */
+  { 0x06b7, 0x0407 }, /*                Ukrainian_YI Ї CYRILLIC CAPITAL LETTER YI */
+  { 0x06b8, 0x0408 }, /*                 Cyrillic_JE Ј CYRILLIC CAPITAL LETTER JE */
+  { 0x06b9, 0x0409 }, /*                Cyrillic_LJE Љ CYRILLIC CAPITAL LETTER LJE */
+  { 0x06ba, 0x040a }, /*                Cyrillic_NJE Њ CYRILLIC CAPITAL LETTER NJE */
+  { 0x06bb, 0x040b }, /*                Serbian_TSHE Ћ CYRILLIC CAPITAL LETTER TSHE */
+  { 0x06bc, 0x040c }, /*               Macedonia_KJE Ќ CYRILLIC CAPITAL LETTER KJE */
+  { 0x06bd, 0x0490 }, /*   Ukrainian_GHE_WITH_UPTURN Ґ CYRILLIC CAPITAL LETTER GHE WITH UPTURN */
+  { 0x06be, 0x040e }, /*         Byelorussian_SHORTU Ў CYRILLIC CAPITAL LETTER SHORT U */
+  { 0x06bf, 0x040f }, /*               Cyrillic_DZHE Џ CYRILLIC CAPITAL LETTER DZHE */
+  { 0x06c0, 0x044e }, /*                 Cyrillic_yu ю CYRILLIC SMALL LETTER YU */
+  { 0x06c1, 0x0430 }, /*                  Cyrillic_a а CYRILLIC SMALL LETTER A */
+  { 0x06c2, 0x0431 }, /*                 Cyrillic_be б CYRILLIC SMALL LETTER BE */
+  { 0x06c3, 0x0446 }, /*                Cyrillic_tse ц CYRILLIC SMALL LETTER TSE */
+  { 0x06c4, 0x0434 }, /*                 Cyrillic_de д CYRILLIC SMALL LETTER DE */
+  { 0x06c5, 0x0435 }, /*                 Cyrillic_ie е CYRILLIC SMALL LETTER IE */
+  { 0x06c6, 0x0444 }, /*                 Cyrillic_ef ф CYRILLIC SMALL LETTER EF */
+  { 0x06c7, 0x0433 }, /*                Cyrillic_ghe г CYRILLIC SMALL LETTER GHE */
+  { 0x06c8, 0x0445 }, /*                 Cyrillic_ha х CYRILLIC SMALL LETTER HA */
+  { 0x06c9, 0x0438 }, /*                  Cyrillic_i и CYRILLIC SMALL LETTER I */
+  { 0x06ca, 0x0439 }, /*             Cyrillic_shorti й CYRILLIC SMALL LETTER SHORT I */
+  { 0x06cb, 0x043a }, /*                 Cyrillic_ka к CYRILLIC SMALL LETTER KA */
+  { 0x06cc, 0x043b }, /*                 Cyrillic_el л CYRILLIC SMALL LETTER EL */
+  { 0x06cd, 0x043c }, /*                 Cyrillic_em м CYRILLIC SMALL LETTER EM */
+  { 0x06ce, 0x043d }, /*                 Cyrillic_en н CYRILLIC SMALL LETTER EN */
+  { 0x06cf, 0x043e }, /*                  Cyrillic_o о CYRILLIC SMALL LETTER O */
+  { 0x06d0, 0x043f }, /*                 Cyrillic_pe п CYRILLIC SMALL LETTER PE */
+  { 0x06d1, 0x044f }, /*                 Cyrillic_ya я CYRILLIC SMALL LETTER YA */
+  { 0x06d2, 0x0440 }, /*                 Cyrillic_er р CYRILLIC SMALL LETTER ER */
+  { 0x06d3, 0x0441 }, /*                 Cyrillic_es с CYRILLIC SMALL LETTER ES */
+  { 0x06d4, 0x0442 }, /*                 Cyrillic_te т CYRILLIC SMALL LETTER TE */
+  { 0x06d5, 0x0443 }, /*                  Cyrillic_u у CYRILLIC SMALL LETTER U */
+  { 0x06d6, 0x0436 }, /*                Cyrillic_zhe ж CYRILLIC SMALL LETTER ZHE */
+  { 0x06d7, 0x0432 }, /*                 Cyrillic_ve в CYRILLIC SMALL LETTER VE */
+  { 0x06d8, 0x044c }, /*           Cyrillic_softsign ь CYRILLIC SMALL LETTER SOFT SIGN */
+  { 0x06d9, 0x044b }, /*               Cyrillic_yeru ы CYRILLIC SMALL LETTER YERU */
+  { 0x06da, 0x0437 }, /*                 Cyrillic_ze з CYRILLIC SMALL LETTER ZE */
+  { 0x06db, 0x0448 }, /*                Cyrillic_sha ш CYRILLIC SMALL LETTER SHA */
+  { 0x06dc, 0x044d }, /*                  Cyrillic_e э CYRILLIC SMALL LETTER E */
+  { 0x06dd, 0x0449 }, /*              Cyrillic_shcha щ CYRILLIC SMALL LETTER SHCHA */
+  { 0x06de, 0x0447 }, /*                Cyrillic_che ч CYRILLIC SMALL LETTER CHE */
+  { 0x06df, 0x044a }, /*           Cyrillic_hardsign ъ CYRILLIC SMALL LETTER HARD SIGN */
+  { 0x06e0, 0x042e }, /*                 Cyrillic_YU Ю CYRILLIC CAPITAL LETTER YU */
+  { 0x06e1, 0x0410 }, /*                  Cyrillic_A А CYRILLIC CAPITAL LETTER A */
+  { 0x06e2, 0x0411 }, /*                 Cyrillic_BE Б CYRILLIC CAPITAL LETTER BE */
+  { 0x06e3, 0x0426 }, /*                Cyrillic_TSE Ц CYRILLIC CAPITAL LETTER TSE */
+  { 0x06e4, 0x0414 }, /*                 Cyrillic_DE Д CYRILLIC CAPITAL LETTER DE */
+  { 0x06e5, 0x0415 }, /*                 Cyrillic_IE Е CYRILLIC CAPITAL LETTER IE */
+  { 0x06e6, 0x0424 }, /*                 Cyrillic_EF Ф CYRILLIC CAPITAL LETTER EF */
+  { 0x06e7, 0x0413 }, /*                Cyrillic_GHE Г CYRILLIC CAPITAL LETTER GHE */
+  { 0x06e8, 0x0425 }, /*                 Cyrillic_HA Х CYRILLIC CAPITAL LETTER HA */
+  { 0x06e9, 0x0418 }, /*                  Cyrillic_I И CYRILLIC CAPITAL LETTER I */
+  { 0x06ea, 0x0419 }, /*             Cyrillic_SHORTI Й CYRILLIC CAPITAL LETTER SHORT I */
+  { 0x06eb, 0x041a }, /*                 Cyrillic_KA К CYRILLIC CAPITAL LETTER KA */
+  { 0x06ec, 0x041b }, /*                 Cyrillic_EL Л CYRILLIC CAPITAL LETTER EL */
+  { 0x06ed, 0x041c }, /*                 Cyrillic_EM М CYRILLIC CAPITAL LETTER EM */
+  { 0x06ee, 0x041d }, /*                 Cyrillic_EN Н CYRILLIC CAPITAL LETTER EN */
+  { 0x06ef, 0x041e }, /*                  Cyrillic_O О CYRILLIC CAPITAL LETTER O */
+  { 0x06f0, 0x041f }, /*                 Cyrillic_PE П CYRILLIC CAPITAL LETTER PE */
+  { 0x06f1, 0x042f }, /*                 Cyrillic_YA Я CYRILLIC CAPITAL LETTER YA */
+  { 0x06f2, 0x0420 }, /*                 Cyrillic_ER Р CYRILLIC CAPITAL LETTER ER */
+  { 0x06f3, 0x0421 }, /*                 Cyrillic_ES С CYRILLIC CAPITAL LETTER ES */
+  { 0x06f4, 0x0422 }, /*                 Cyrillic_TE Т CYRILLIC CAPITAL LETTER TE */
+  { 0x06f5, 0x0423 }, /*                  Cyrillic_U У CYRILLIC CAPITAL LETTER U */
+  { 0x06f6, 0x0416 }, /*                Cyrillic_ZHE Ж CYRILLIC CAPITAL LETTER ZHE */
+  { 0x06f7, 0x0412 }, /*                 Cyrillic_VE В CYRILLIC CAPITAL LETTER VE */
+  { 0x06f8, 0x042c }, /*           Cyrillic_SOFTSIGN Ь CYRILLIC CAPITAL LETTER SOFT SIGN */
+  { 0x06f9, 0x042b }, /*               Cyrillic_YERU Ы CYRILLIC CAPITAL LETTER YERU */
+  { 0x06fa, 0x0417 }, /*                 Cyrillic_ZE З CYRILLIC CAPITAL LETTER ZE */
+  { 0x06fb, 0x0428 }, /*                Cyrillic_SHA Ш CYRILLIC CAPITAL LETTER SHA */
+  { 0x06fc, 0x042d }, /*                  Cyrillic_E Э CYRILLIC CAPITAL LETTER E */
+  { 0x06fd, 0x0429 }, /*              Cyrillic_SHCHA Щ CYRILLIC CAPITAL LETTER SHCHA */
+  { 0x06fe, 0x0427 }, /*                Cyrillic_CHE Ч CYRILLIC CAPITAL LETTER CHE */
+  { 0x06ff, 0x042a }, /*           Cyrillic_HARDSIGN Ъ CYRILLIC CAPITAL LETTER HARD SIGN */
+  { 0x07a1, 0x0386 }, /*           Greek_ALPHAaccent Ά GREEK CAPITAL LETTER ALPHA WITH TONOS */
+  { 0x07a2, 0x0388 }, /*         Greek_EPSILONaccent Έ GREEK CAPITAL LETTER EPSILON WITH TONOS */
+  { 0x07a3, 0x0389 }, /*             Greek_ETAaccent Ή GREEK CAPITAL LETTER ETA WITH TONOS */
+  { 0x07a4, 0x038a }, /*            Greek_IOTAaccent Ί GREEK CAPITAL LETTER IOTA WITH TONOS */
+  { 0x07a5, 0x03aa }, /*         Greek_IOTAdiaeresis Ϊ GREEK CAPITAL LETTER IOTA WITH DIALYTIKA */
+  { 0x07a7, 0x038c }, /*         Greek_OMICRONaccent Ό GREEK CAPITAL LETTER OMICRON WITH TONOS */
+  { 0x07a8, 0x038e }, /*         Greek_UPSILONaccent Ύ GREEK CAPITAL LETTER UPSILON WITH TONOS */
+  { 0x07a9, 0x03ab }, /*       Greek_UPSILONdieresis Ϋ GREEK CAPITAL LETTER UPSILON WITH DIALYTIKA */
+  { 0x07ab, 0x038f }, /*           Greek_OMEGAaccent Ώ GREEK CAPITAL LETTER OMEGA WITH TONOS */
+  { 0x07ae, 0x0385 }, /*        Greek_accentdieresis ΅ GREEK DIALYTIKA TONOS */
+  { 0x07af, 0x2015 }, /*              Greek_horizbar ― HORIZONTAL BAR */
+  { 0x07b1, 0x03ac }, /*           Greek_alphaaccent ά GREEK SMALL LETTER ALPHA WITH TONOS */
+  { 0x07b2, 0x03ad }, /*         Greek_epsilonaccent έ GREEK SMALL LETTER EPSILON WITH TONOS */
+  { 0x07b3, 0x03ae }, /*             Greek_etaaccent ή GREEK SMALL LETTER ETA WITH TONOS */
+  { 0x07b4, 0x03af }, /*            Greek_iotaaccent ί GREEK SMALL LETTER IOTA WITH TONOS */
+  { 0x07b5, 0x03ca }, /*          Greek_iotadieresis ϊ GREEK SMALL LETTER IOTA WITH DIALYTIKA */
+  { 0x07b6, 0x0390 }, /*    Greek_iotaaccentdieresis ΐ GREEK SMALL LETTER IOTA WITH DIALYTIKA AND TONOS */
+  { 0x07b7, 0x03cc }, /*         Greek_omicronaccent ό GREEK SMALL LETTER OMICRON WITH TONOS */
+  { 0x07b8, 0x03cd }, /*         Greek_upsilonaccent ύ GREEK SMALL LETTER UPSILON WITH TONOS */
+  { 0x07b9, 0x03cb }, /*       Greek_upsilondieresis ϋ GREEK SMALL LETTER UPSILON WITH DIALYTIKA */
+  { 0x07ba, 0x03b0 }, /* Greek_upsilonaccentdieresis ΰ GREEK SMALL LETTER UPSILON WITH DIALYTIKA AND TONOS */
+  { 0x07bb, 0x03ce }, /*           Greek_omegaaccent ώ GREEK SMALL LETTER OMEGA WITH TONOS */
+  { 0x07c1, 0x0391 }, /*                 Greek_ALPHA Α GREEK CAPITAL LETTER ALPHA */
+  { 0x07c2, 0x0392 }, /*                  Greek_BETA Β GREEK CAPITAL LETTER BETA */
+  { 0x07c3, 0x0393 }, /*                 Greek_GAMMA Γ GREEK CAPITAL LETTER GAMMA */
+  { 0x07c4, 0x0394 }, /*                 Greek_DELTA Δ GREEK CAPITAL LETTER DELTA */
+  { 0x07c5, 0x0395 }, /*               Greek_EPSILON Ε GREEK CAPITAL LETTER EPSILON */
+  { 0x07c6, 0x0396 }, /*                  Greek_ZETA Ζ GREEK CAPITAL LETTER ZETA */
+  { 0x07c7, 0x0397 }, /*                   Greek_ETA Η GREEK CAPITAL LETTER ETA */
+  { 0x07c8, 0x0398 }, /*                 Greek_THETA Θ GREEK CAPITAL LETTER THETA */
+  { 0x07c9, 0x0399 }, /*                  Greek_IOTA Ι GREEK CAPITAL LETTER IOTA */
+  { 0x07ca, 0x039a }, /*                 Greek_KAPPA Κ GREEK CAPITAL LETTER KAPPA */
+  { 0x07cb, 0x039b }, /*                Greek_LAMBDA Λ GREEK CAPITAL LETTER LAMDA */
+  { 0x07cc, 0x039c }, /*                    Greek_MU Μ GREEK CAPITAL LETTER MU */
+  { 0x07cd, 0x039d }, /*                    Greek_NU Ν GREEK CAPITAL LETTER NU */
+  { 0x07ce, 0x039e }, /*                    Greek_XI Ξ GREEK CAPITAL LETTER XI */
+  { 0x07cf, 0x039f }, /*               Greek_OMICRON Ο GREEK CAPITAL LETTER OMICRON */
+  { 0x07d0, 0x03a0 }, /*                    Greek_PI Π GREEK CAPITAL LETTER PI */
+  { 0x07d1, 0x03a1 }, /*                   Greek_RHO Ρ GREEK CAPITAL LETTER RHO */
+  { 0x07d2, 0x03a3 }, /*                 Greek_SIGMA Σ GREEK CAPITAL LETTER SIGMA */
+  { 0x07d4, 0x03a4 }, /*                   Greek_TAU Τ GREEK CAPITAL LETTER TAU */
+  { 0x07d5, 0x03a5 }, /*               Greek_UPSILON Υ GREEK CAPITAL LETTER UPSILON */
+  { 0x07d6, 0x03a6 }, /*                   Greek_PHI Φ GREEK CAPITAL LETTER PHI */
+  { 0x07d7, 0x03a7 }, /*                   Greek_CHI Χ GREEK CAPITAL LETTER CHI */
+  { 0x07d8, 0x03a8 }, /*                   Greek_PSI Ψ GREEK CAPITAL LETTER PSI */
+  { 0x07d9, 0x03a9 }, /*                 Greek_OMEGA Ω GREEK CAPITAL LETTER OMEGA */
+  { 0x07e1, 0x03b1 }, /*                 Greek_alpha α GREEK SMALL LETTER ALPHA */
+  { 0x07e2, 0x03b2 }, /*                  Greek_beta β GREEK SMALL LETTER BETA */
+  { 0x07e3, 0x03b3 }, /*                 Greek_gamma γ GREEK SMALL LETTER GAMMA */
+  { 0x07e4, 0x03b4 }, /*                 Greek_delta δ GREEK SMALL LETTER DELTA */
+  { 0x07e5, 0x03b5 }, /*               Greek_epsilon ε GREEK SMALL LETTER EPSILON */
+  { 0x07e6, 0x03b6 }, /*                  Greek_zeta ζ GREEK SMALL LETTER ZETA */
+  { 0x07e7, 0x03b7 }, /*                   Greek_eta η GREEK SMALL LETTER ETA */
+  { 0x07e8, 0x03b8 }, /*                 Greek_theta θ GREEK SMALL LETTER THETA */
+  { 0x07e9, 0x03b9 }, /*                  Greek_iota ι GREEK SMALL LETTER IOTA */
+  { 0x07ea, 0x03ba }, /*                 Greek_kappa κ GREEK SMALL LETTER KAPPA */
+  { 0x07eb, 0x03bb }, /*                Greek_lambda λ GREEK SMALL LETTER LAMDA */
+  { 0x07ec, 0x03bc }, /*                    Greek_mu μ GREEK SMALL LETTER MU */
+  { 0x07ed, 0x03bd }, /*                    Greek_nu ν GREEK SMALL LETTER NU */
+  { 0x07ee, 0x03be }, /*                    Greek_xi ξ GREEK SMALL LETTER XI */
+  { 0x07ef, 0x03bf }, /*               Greek_omicron ο GREEK SMALL LETTER OMICRON */
+  { 0x07f0, 0x03c0 }, /*                    Greek_pi π GREEK SMALL LETTER PI */
+  { 0x07f1, 0x03c1 }, /*                   Greek_rho ρ GREEK SMALL LETTER RHO */
+  { 0x07f2, 0x03c3 }, /*                 Greek_sigma σ GREEK SMALL LETTER SIGMA */
+  { 0x07f3, 0x03c2 }, /*       Greek_finalsmallsigma ς GREEK SMALL LETTER FINAL SIGMA */
+  { 0x07f4, 0x03c4 }, /*                   Greek_tau τ GREEK SMALL LETTER TAU */
+  { 0x07f5, 0x03c5 }, /*               Greek_upsilon υ GREEK SMALL LETTER UPSILON */
+  { 0x07f6, 0x03c6 }, /*                   Greek_phi φ GREEK SMALL LETTER PHI */
+  { 0x07f7, 0x03c7 }, /*                   Greek_chi χ GREEK SMALL LETTER CHI */
+  { 0x07f8, 0x03c8 }, /*                   Greek_psi ψ GREEK SMALL LETTER PSI */
+  { 0x07f9, 0x03c9 }, /*                 Greek_omega ω GREEK SMALL LETTER OMEGA */
+/*  0x08a1                               leftradical ? ??? */
+/*  0x08a2                            topleftradical ? ??? */
+/*  0x08a3                            horizconnector ? ??? */
+  { 0x08a4, 0x2320 }, /*                 topintegral ⌠ TOP HALF INTEGRAL */
+  { 0x08a5, 0x2321 }, /*                 botintegral ⌡ BOTTOM HALF INTEGRAL */
+  { 0x08a6, 0x2502 }, /*               vertconnector │ BOX DRAWINGS LIGHT VERTICAL */
+/*  0x08a7                          topleftsqbracket ? ??? */
+/*  0x08a8                          botleftsqbracket ? ??? */
+/*  0x08a9                         toprightsqbracket ? ??? */
+/*  0x08aa                         botrightsqbracket ? ??? */
+/*  0x08ab                             topleftparens ? ??? */
+/*  0x08ac                             botleftparens ? ??? */
+/*  0x08ad                            toprightparens ? ??? */
+/*  0x08ae                            botrightparens ? ??? */
+/*  0x08af                      leftmiddlecurlybrace ? ??? */
+/*  0x08b0                     rightmiddlecurlybrace ? ??? */
+/*  0x08b1                          topleftsummation ? ??? */
+/*  0x08b2                          botleftsummation ? ??? */
+/*  0x08b3                 topvertsummationconnector ? ??? */
+/*  0x08b4                 botvertsummationconnector ? ??? */
+/*  0x08b5                         toprightsummation ? ??? */
+/*  0x08b6                         botrightsummation ? ??? */
+/*  0x08b7                      rightmiddlesummation ? ??? */
+  { 0x08bc, 0x2264 }, /*               lessthanequal ≤ LESS-THAN OR EQUAL TO */
+  { 0x08bd, 0x2260 }, /*                    notequal ≠ NOT EQUAL TO */
+  { 0x08be, 0x2265 }, /*            greaterthanequal ≥ GREATER-THAN OR EQUAL TO */
+  { 0x08bf, 0x222b }, /*                    integral ∫ INTEGRAL */
+  { 0x08c0, 0x2234 }, /*                   therefore ∴ THEREFORE */
+  { 0x08c1, 0x221d }, /*                   variation ∝ PROPORTIONAL TO */
+  { 0x08c2, 0x221e }, /*                    infinity ∞ INFINITY */
+  { 0x08c5, 0x2207 }, /*                       nabla ∇ NABLA */
+  { 0x08c8, 0x2245 }, /*                 approximate ≅ APPROXIMATELY EQUAL TO */
+/*  0x08c9                              similarequal ? ??? */
+  { 0x08cd, 0x21d4 }, /*                    ifonlyif ⇔ LEFT RIGHT DOUBLE ARROW */
+  { 0x08ce, 0x21d2 }, /*                     implies ⇒ RIGHTWARDS DOUBLE ARROW */
+  { 0x08cf, 0x2261 }, /*                   identical ≡ IDENTICAL TO */
+  { 0x08d6, 0x221a }, /*                     radical √ SQUARE ROOT */
+  { 0x08da, 0x2282 }, /*                  includedin ⊂ SUBSET OF */
+  { 0x08db, 0x2283 }, /*                    includes ⊃ SUPERSET OF */
+  { 0x08dc, 0x2229 }, /*                intersection ∩ INTERSECTION */
+  { 0x08dd, 0x222a }, /*                       union ∪ UNION */
+  { 0x08de, 0x2227 }, /*                  logicaland ∧ LOGICAL AND */
+  { 0x08df, 0x2228 }, /*                   logicalor ∨ LOGICAL OR */
+  { 0x08ef, 0x2202 }, /*           partialderivative ∂ PARTIAL DIFFERENTIAL */
+  { 0x08f6, 0x0192 }, /*                    function ƒ LATIN SMALL LETTER F WITH HOOK */
+  { 0x08fb, 0x2190 }, /*                   leftarrow ← LEFTWARDS ARROW */
+  { 0x08fc, 0x2191 }, /*                     uparrow ↑ UPWARDS ARROW */
+  { 0x08fd, 0x2192 }, /*                  rightarrow → RIGHTWARDS ARROW */
+  { 0x08fe, 0x2193 }, /*                   downarrow ↓ DOWNWARDS ARROW */
+  { 0x09df, 0x2422 }, /*                       blank ␢ BLANK SYMBOL */
+  { 0x09e0, 0x25c6 }, /*                soliddiamond ◆ BLACK DIAMOND */
+  { 0x09e1, 0x2592 }, /*                checkerboard ▒ MEDIUM SHADE */
+  { 0x09e2, 0x2409 }, /*                          ht ␉ SYMBOL FOR HORIZONTAL TABULATION */
+  { 0x09e3, 0x240c }, /*                          ff ␌ SYMBOL FOR FORM FEED */
+  { 0x09e4, 0x240d }, /*                          cr ␍ SYMBOL FOR CARRIAGE RETURN */
+  { 0x09e5, 0x240a }, /*                          lf ␊ SYMBOL FOR LINE FEED */
+  { 0x09e8, 0x2424 }, /*                          nl ␤ SYMBOL FOR NEWLINE */
+  { 0x09e9, 0x240b }, /*                          vt ␋ SYMBOL FOR VERTICAL TABULATION */
+  { 0x09ea, 0x2518 }, /*              lowrightcorner ┘ BOX DRAWINGS LIGHT UP AND LEFT */
+  { 0x09eb, 0x2510 }, /*               uprightcorner ┐ BOX DRAWINGS LIGHT DOWN AND LEFT */
+  { 0x09ec, 0x250c }, /*                upleftcorner ┌ BOX DRAWINGS LIGHT DOWN AND RIGHT */
+  { 0x09ed, 0x2514 }, /*               lowleftcorner └ BOX DRAWINGS LIGHT UP AND RIGHT */
+  { 0x09ee, 0x253c }, /*               crossinglines ┼ BOX DRAWINGS LIGHT VERTICAL AND HORIZONTAL */
+/*  0x09ef                            horizlinescan1 ? ??? */
+/*  0x09f0                            horizlinescan3 ? ??? */
+  { 0x09f1, 0x2500 }, /*              horizlinescan5 ─ BOX DRAWINGS LIGHT HORIZONTAL */
+/*  0x09f2                            horizlinescan7 ? ??? */
+/*  0x09f3                            horizlinescan9 ? ??? */
+  { 0x09f4, 0x251c }, /*                       leftt ├ BOX DRAWINGS LIGHT VERTICAL AND RIGHT */
+  { 0x09f5, 0x2524 }, /*                      rightt ┤ BOX DRAWINGS LIGHT VERTICAL AND LEFT */
+  { 0x09f6, 0x2534 }, /*                        bott ┴ BOX DRAWINGS LIGHT UP AND HORIZONTAL */
+  { 0x09f7, 0x252c }, /*                        topt ┬ BOX DRAWINGS LIGHT DOWN AND HORIZONTAL */
+  { 0x09f8, 0x2502 }, /*                     vertbar │ BOX DRAWINGS LIGHT VERTICAL */
+  { 0x0aa1, 0x2003 }, /*                     emspace   EM SPACE */
+  { 0x0aa2, 0x2002 }, /*                     enspace   EN SPACE */
+  { 0x0aa3, 0x2004 }, /*                    em3space   THREE-PER-EM SPACE */
+  { 0x0aa4, 0x2005 }, /*                    em4space   FOUR-PER-EM SPACE */
+  { 0x0aa5, 0x2007 }, /*                  digitspace   FIGURE SPACE */
+  { 0x0aa6, 0x2008 }, /*                  punctspace   PUNCTUATION SPACE */
+  { 0x0aa7, 0x2009 }, /*                   thinspace   THIN SPACE */
+  { 0x0aa8, 0x200a }, /*                   hairspace   HAIR SPACE */
+  { 0x0aa9, 0x2014 }, /*                      emdash — EM DASH */
+  { 0x0aaa, 0x2013 }, /*                      endash – EN DASH */
+/*  0x0aac                               signifblank ? ??? */
+  { 0x0aae, 0x2026 }, /*                    ellipsis … HORIZONTAL ELLIPSIS */
+/*  0x0aaf                           doubbaselinedot ? ??? */
+  { 0x0ab0, 0x2153 }, /*                    onethird ⅓ VULGAR FRACTION ONE THIRD */
+  { 0x0ab1, 0x2154 }, /*                   twothirds ⅔ VULGAR FRACTION TWO THIRDS */
+  { 0x0ab2, 0x2155 }, /*                    onefifth ⅕ VULGAR FRACTION ONE FIFTH */
+  { 0x0ab3, 0x2156 }, /*                   twofifths ⅖ VULGAR FRACTION TWO FIFTHS */
+  { 0x0ab4, 0x2157 }, /*                 threefifths ⅗ VULGAR FRACTION THREE FIFTHS */
+  { 0x0ab5, 0x2158 }, /*                  fourfifths ⅘ VULGAR FRACTION FOUR FIFTHS */
+  { 0x0ab6, 0x2159 }, /*                    onesixth ⅙ VULGAR FRACTION ONE SIXTH */
+  { 0x0ab7, 0x215a }, /*                  fivesixths ⅚ VULGAR FRACTION FIVE SIXTHS */
+  { 0x0ab8, 0x2105 }, /*                      careof ℅ CARE OF */
+  { 0x0abb, 0x2012 }, /*                     figdash ‒ FIGURE DASH */
+  { 0x0abc, 0x2329 }, /*            leftanglebracket 〈 LEFT-POINTING ANGLE BRACKET */
+  { 0x0abd, 0x002e }, /*                decimalpoint . FULL STOP */
+  { 0x0abe, 0x232a }, /*           rightanglebracket 〉 RIGHT-POINTING ANGLE BRACKET */
+/*  0x0abf                                    marker ? ??? */
+  { 0x0ac3, 0x215b }, /*                   oneeighth ⅛ VULGAR FRACTION ONE EIGHTH */
+  { 0x0ac4, 0x215c }, /*                threeeighths ⅜ VULGAR FRACTION THREE EIGHTHS */
+  { 0x0ac5, 0x215d }, /*                 fiveeighths ⅝ VULGAR FRACTION FIVE EIGHTHS */
+  { 0x0ac6, 0x215e }, /*                seveneighths ⅞ VULGAR FRACTION SEVEN EIGHTHS */
+  { 0x0ac9, 0x2122 }, /*                   trademark ™ TRADE MARK SIGN */
+  { 0x0aca, 0x2613 }, /*               signaturemark ☓ SALTIRE */
+/*  0x0acb                         trademarkincircle ? ??? */
+  { 0x0acc, 0x25c1 }, /*            leftopentriangle ◁ WHITE LEFT-POINTING TRIANGLE */
+  { 0x0acd, 0x25b7 }, /*           rightopentriangle ▷ WHITE RIGHT-POINTING TRIANGLE */
+  { 0x0ace, 0x25cb }, /*                emopencircle ○ WHITE CIRCLE */
+  { 0x0acf, 0x25a1 }, /*             emopenrectangle □ WHITE SQUARE */
+  { 0x0ad0, 0x2018 }, /*         leftsinglequotemark ‘ LEFT SINGLE QUOTATION MARK */
+  { 0x0ad1, 0x2019 }, /*        rightsinglequotemark ’ RIGHT SINGLE QUOTATION MARK */
+  { 0x0ad2, 0x201c }, /*         leftdoublequotemark “ LEFT DOUBLE QUOTATION MARK */
+  { 0x0ad3, 0x201d }, /*        rightdoublequotemark ” RIGHT DOUBLE QUOTATION MARK */
+  { 0x0ad4, 0x211e }, /*                prescription ℞ PRESCRIPTION TAKE */
+  { 0x0ad6, 0x2032 }, /*                     minutes ′ PRIME */
+  { 0x0ad7, 0x2033 }, /*                     seconds ″ DOUBLE PRIME */
+  { 0x0ad9, 0x271d }, /*                  latincross ✝ LATIN CROSS */
+/*  0x0ada                                  hexagram ? ??? */
+  { 0x0adb, 0x25ac }, /*            filledrectbullet ▬ BLACK RECTANGLE */
+  { 0x0adc, 0x25c0 }, /*         filledlefttribullet ◀ BLACK LEFT-POINTING TRIANGLE */
+  { 0x0add, 0x25b6 }, /*        filledrighttribullet ▶ BLACK RIGHT-POINTING TRIANGLE */
+  { 0x0ade, 0x25cf }, /*              emfilledcircle ● BLACK CIRCLE */
+  { 0x0adf, 0x25a0 }, /*                emfilledrect ■ BLACK SQUARE */
+  { 0x0ae0, 0x25e6 }, /*            enopencircbullet ◦ WHITE BULLET */
+  { 0x0ae1, 0x25ab }, /*          enopensquarebullet ▫ WHITE SMALL SQUARE */
+  { 0x0ae2, 0x25ad }, /*              openrectbullet ▭ WHITE RECTANGLE */
+  { 0x0ae3, 0x25b3 }, /*             opentribulletup △ WHITE UP-POINTING TRIANGLE */
+  { 0x0ae4, 0x25bd }, /*           opentribulletdown ▽ WHITE DOWN-POINTING TRIANGLE */
+  { 0x0ae5, 0x2606 }, /*                    openstar ☆ WHITE STAR */
+  { 0x0ae6, 0x2022 }, /*          enfilledcircbullet • BULLET */
+  { 0x0ae7, 0x25aa }, /*            enfilledsqbullet ▪ BLACK SMALL SQUARE */
+  { 0x0ae8, 0x25b2 }, /*           filledtribulletup ▲ BLACK UP-POINTING TRIANGLE */
+  { 0x0ae9, 0x25bc }, /*         filledtribulletdown ▼ BLACK DOWN-POINTING TRIANGLE */
+  { 0x0aea, 0x261c }, /*                 leftpointer ☜ WHITE LEFT POINTING INDEX */
+  { 0x0aeb, 0x261e }, /*                rightpointer ☞ WHITE RIGHT POINTING INDEX */
+  { 0x0aec, 0x2663 }, /*                        club ♣ BLACK CLUB SUIT */
+  { 0x0aed, 0x2666 }, /*                     diamond ♦ BLACK DIAMOND SUIT */
+  { 0x0aee, 0x2665 }, /*                       heart ♥ BLACK HEART SUIT */
+  { 0x0af0, 0x2720 }, /*                maltesecross ✠ MALTESE CROSS */
+  { 0x0af1, 0x2020 }, /*                      dagger † DAGGER */
+  { 0x0af2, 0x2021 }, /*                doubledagger ‡ DOUBLE DAGGER */
+  { 0x0af3, 0x2713 }, /*                   checkmark ✓ CHECK MARK */
+  { 0x0af4, 0x2717 }, /*                 ballotcross ✗ BALLOT X */
+  { 0x0af5, 0x266f }, /*                musicalsharp ♯ MUSIC SHARP SIGN */
+  { 0x0af6, 0x266d }, /*                 musicalflat ♭ MUSIC FLAT SIGN */
+  { 0x0af7, 0x2642 }, /*                  malesymbol ♂ MALE SIGN */
+  { 0x0af8, 0x2640 }, /*                femalesymbol ♀ FEMALE SIGN */
+  { 0x0af9, 0x260e }, /*                   telephone ☎ BLACK TELEPHONE */
+  { 0x0afa, 0x2315 }, /*           telephonerecorder ⌕ TELEPHONE RECORDER */
+  { 0x0afb, 0x2117 }, /*         phonographcopyright ℗ SOUND RECORDING COPYRIGHT */
+  { 0x0afc, 0x2038 }, /*                       caret ‸ CARET */
+  { 0x0afd, 0x201a }, /*          singlelowquotemark ‚ SINGLE LOW-9 QUOTATION MARK */
+  { 0x0afe, 0x201e }, /*          doublelowquotemark „ DOUBLE LOW-9 QUOTATION MARK */
+/*  0x0aff                                    cursor ? ??? */
+  { 0x0ba3, 0x003c }, /*                   leftcaret < LESS-THAN SIGN */
+  { 0x0ba6, 0x003e }, /*                  rightcaret > GREATER-THAN SIGN */
+  { 0x0ba8, 0x2228 }, /*                   downcaret ∨ LOGICAL OR */
+  { 0x0ba9, 0x2227 }, /*                     upcaret ∧ LOGICAL AND */
+  { 0x0bc0, 0x00af }, /*                     overbar ¯ MACRON */
+  { 0x0bc2, 0x22a4 }, /*                    downtack ⊤ DOWN TACK */
+  { 0x0bc3, 0x2229 }, /*                      upshoe ∩ INTERSECTION */
+  { 0x0bc4, 0x230a }, /*                   downstile ⌊ LEFT FLOOR */
+  { 0x0bc6, 0x005f }, /*                    underbar _ LOW LINE */
+  { 0x0bca, 0x2218 }, /*                         jot ∘ RING OPERATOR */
+  { 0x0bcc, 0x2395 }, /*                        quad ⎕ APL FUNCTIONAL SYMBOL QUAD (Unicode 3.0) */
+  { 0x0bce, 0x22a5 }, /*                      uptack ⊥ UP TACK */
+  { 0x0bcf, 0x25cb }, /*                      circle ○ WHITE CIRCLE */
+  { 0x0bd3, 0x2308 }, /*                     upstile ⌈ LEFT CEILING */
+  { 0x0bd6, 0x222a }, /*                    downshoe ∪ UNION */
+  { 0x0bd8, 0x2283 }, /*                   rightshoe ⊃ SUPERSET OF */
+  { 0x0bda, 0x2282 }, /*                    leftshoe ⊂ SUBSET OF */
+  { 0x0bdc, 0x22a3 }, /*                    lefttack ⊣ LEFT TACK */
+  { 0x0bfc, 0x22a2 }, /*                   righttack ⊢ RIGHT TACK */
+  { 0x0cdf, 0x2017 }, /*        hebrew_doublelowline ‗ DOUBLE LOW LINE */
+  { 0x0ce0, 0x05d0 }, /*                hebrew_aleph א HEBREW LETTER ALEF */
+  { 0x0ce1, 0x05d1 }, /*                  hebrew_bet ב HEBREW LETTER BET */
+  { 0x0ce2, 0x05d2 }, /*                hebrew_gimel ג HEBREW LETTER GIMEL */
+  { 0x0ce3, 0x05d3 }, /*                hebrew_dalet ד HEBREW LETTER DALET */
+  { 0x0ce4, 0x05d4 }, /*                   hebrew_he ה HEBREW LETTER HE */
+  { 0x0ce5, 0x05d5 }, /*                  hebrew_waw ו HEBREW LETTER VAV */
+  { 0x0ce6, 0x05d6 }, /*                 hebrew_zain ז HEBREW LETTER ZAYIN */
+  { 0x0ce7, 0x05d7 }, /*                 hebrew_chet ח HEBREW LETTER HET */
+  { 0x0ce8, 0x05d8 }, /*                  hebrew_tet ט HEBREW LETTER TET */
+  { 0x0ce9, 0x05d9 }, /*                  hebrew_yod י HEBREW LETTER YOD */
+  { 0x0cea, 0x05da }, /*            hebrew_finalkaph ך HEBREW LETTER FINAL KAF */
+  { 0x0ceb, 0x05db }, /*                 hebrew_kaph כ HEBREW LETTER KAF */
+  { 0x0cec, 0x05dc }, /*                hebrew_lamed ל HEBREW LETTER LAMED */
+  { 0x0ced, 0x05dd }, /*             hebrew_finalmem ם HEBREW LETTER FINAL MEM */
+  { 0x0cee, 0x05de }, /*                  hebrew_mem מ HEBREW LETTER MEM */
+  { 0x0cef, 0x05df }, /*             hebrew_finalnun ן HEBREW LETTER FINAL NUN */
+  { 0x0cf0, 0x05e0 }, /*                  hebrew_nun נ HEBREW LETTER NUN */
+  { 0x0cf1, 0x05e1 }, /*               hebrew_samech ס HEBREW LETTER SAMEKH */
+  { 0x0cf2, 0x05e2 }, /*                 hebrew_ayin ע HEBREW LETTER AYIN */
+  { 0x0cf3, 0x05e3 }, /*              hebrew_finalpe ף HEBREW LETTER FINAL PE */
+  { 0x0cf4, 0x05e4 }, /*                   hebrew_pe פ HEBREW LETTER PE */
+  { 0x0cf5, 0x05e5 }, /*            hebrew_finalzade ץ HEBREW LETTER FINAL TSADI */
+  { 0x0cf6, 0x05e6 }, /*                 hebrew_zade צ HEBREW LETTER TSADI */
+  { 0x0cf7, 0x05e7 }, /*                 hebrew_qoph ק HEBREW LETTER QOF */
+  { 0x0cf8, 0x05e8 }, /*                 hebrew_resh ר HEBREW LETTER RESH */
+  { 0x0cf9, 0x05e9 }, /*                 hebrew_shin ש HEBREW LETTER SHIN */
+  { 0x0cfa, 0x05ea }, /*                  hebrew_taw ת HEBREW LETTER TAV */
+  { 0x0da1, 0x0e01 }, /*                  Thai_kokai ก THAI CHARACTER KO KAI */
+  { 0x0da2, 0x0e02 }, /*                Thai_khokhai ข THAI CHARACTER KHO KHAI */
+  { 0x0da3, 0x0e03 }, /*               Thai_khokhuat ฃ THAI CHARACTER KHO KHUAT */
+  { 0x0da4, 0x0e04 }, /*               Thai_khokhwai ค THAI CHARACTER KHO KHWAI */
+  { 0x0da5, 0x0e05 }, /*                Thai_khokhon ฅ THAI CHARACTER KHO KHON */
+  { 0x0da6, 0x0e06 }, /*             Thai_khorakhang ฆ THAI CHARACTER KHO RAKHANG */
+  { 0x0da7, 0x0e07 }, /*                 Thai_ngongu ง THAI CHARACTER NGO NGU */
+  { 0x0da8, 0x0e08 }, /*                Thai_chochan จ THAI CHARACTER CHO CHAN */
+  { 0x0da9, 0x0e09 }, /*               Thai_choching ฉ THAI CHARACTER CHO CHING */
+  { 0x0daa, 0x0e0a }, /*               Thai_chochang ช THAI CHARACTER CHO CHANG */
+  { 0x0dab, 0x0e0b }, /*                   Thai_soso ซ THAI CHARACTER SO SO */
+  { 0x0dac, 0x0e0c }, /*                Thai_chochoe ฌ THAI CHARACTER CHO CHOE */
+  { 0x0dad, 0x0e0d }, /*                 Thai_yoying ญ THAI CHARACTER YO YING */
+  { 0x0dae, 0x0e0e }, /*                Thai_dochada ฎ THAI CHARACTER DO CHADA */
+  { 0x0daf, 0x0e0f }, /*                Thai_topatak ฏ THAI CHARACTER TO PATAK */
+  { 0x0db0, 0x0e10 }, /*                Thai_thothan ฐ THAI CHARACTER THO THAN */
+  { 0x0db1, 0x0e11 }, /*          Thai_thonangmontho ฑ THAI CHARACTER THO NANGMONTHO */
+  { 0x0db2, 0x0e12 }, /*             Thai_thophuthao ฒ THAI CHARACTER THO PHUTHAO */
+  { 0x0db3, 0x0e13 }, /*                  Thai_nonen ณ THAI CHARACTER NO NEN */
+  { 0x0db4, 0x0e14 }, /*                  Thai_dodek ด THAI CHARACTER DO DEK */
+  { 0x0db5, 0x0e15 }, /*                  Thai_totao ต THAI CHARACTER TO TAO */
+  { 0x0db6, 0x0e16 }, /*               Thai_thothung ถ THAI CHARACTER THO THUNG */
+  { 0x0db7, 0x0e17 }, /*              Thai_thothahan ท THAI CHARACTER THO THAHAN */
+  { 0x0db8, 0x0e18 }, /*               Thai_thothong ธ THAI CHARACTER THO THONG */
+  { 0x0db9, 0x0e19 }, /*                   Thai_nonu น THAI CHARACTER NO NU */
+  { 0x0dba, 0x0e1a }, /*               Thai_bobaimai บ THAI CHARACTER BO BAIMAI */
+  { 0x0dbb, 0x0e1b }, /*                  Thai_popla ป THAI CHARACTER PO PLA */
+  { 0x0dbc, 0x0e1c }, /*               Thai_phophung ผ THAI CHARACTER PHO PHUNG */
+  { 0x0dbd, 0x0e1d }, /*                   Thai_fofa ฝ THAI CHARACTER FO FA */
+  { 0x0dbe, 0x0e1e }, /*                Thai_phophan พ THAI CHARACTER PHO PHAN */
+  { 0x0dbf, 0x0e1f }, /*                  Thai_fofan ฟ THAI CHARACTER FO FAN */
+  { 0x0dc0, 0x0e20 }, /*             Thai_phosamphao ภ THAI CHARACTER PHO SAMPHAO */
+  { 0x0dc1, 0x0e21 }, /*                   Thai_moma ม THAI CHARACTER MO MA */
+  { 0x0dc2, 0x0e22 }, /*                  Thai_yoyak ย THAI CHARACTER YO YAK */
+  { 0x0dc3, 0x0e23 }, /*                  Thai_rorua ร THAI CHARACTER RO RUA */
+  { 0x0dc4, 0x0e24 }, /*                     Thai_ru ฤ THAI CHARACTER RU */
+  { 0x0dc5, 0x0e25 }, /*                 Thai_loling ล THAI CHARACTER LO LING */
+  { 0x0dc6, 0x0e26 }, /*                     Thai_lu ฦ THAI CHARACTER LU */
+  { 0x0dc7, 0x0e27 }, /*                 Thai_wowaen ว THAI CHARACTER WO WAEN */
+  { 0x0dc8, 0x0e28 }, /*                 Thai_sosala ศ THAI CHARACTER SO SALA */
+  { 0x0dc9, 0x0e29 }, /*                 Thai_sorusi ษ THAI CHARACTER SO RUSI */
+  { 0x0dca, 0x0e2a }, /*                  Thai_sosua ส THAI CHARACTER SO SUA */
+  { 0x0dcb, 0x0e2b }, /*                  Thai_hohip ห THAI CHARACTER HO HIP */
+  { 0x0dcc, 0x0e2c }, /*                Thai_lochula ฬ THAI CHARACTER LO CHULA */
+  { 0x0dcd, 0x0e2d }, /*                   Thai_oang อ THAI CHARACTER O ANG */
+  { 0x0dce, 0x0e2e }, /*               Thai_honokhuk ฮ THAI CHARACTER HO NOKHUK */
+  { 0x0dcf, 0x0e2f }, /*              Thai_paiyannoi ฯ THAI CHARACTER PAIYANNOI */
+  { 0x0dd0, 0x0e30 }, /*                  Thai_saraa ะ THAI CHARACTER SARA A */
+  { 0x0dd1, 0x0e31 }, /*             Thai_maihanakat ั THAI CHARACTER MAI HAN-AKAT */
+  { 0x0dd2, 0x0e32 }, /*                 Thai_saraaa า THAI CHARACTER SARA AA */
+  { 0x0dd3, 0x0e33 }, /*                 Thai_saraam ำ THAI CHARACTER SARA AM */
+  { 0x0dd4, 0x0e34 }, /*                  Thai_sarai ิ THAI CHARACTER SARA I */
+  { 0x0dd5, 0x0e35 }, /*                 Thai_saraii ี THAI CHARACTER SARA II */
+  { 0x0dd6, 0x0e36 }, /*                 Thai_saraue ึ THAI CHARACTER SARA UE */
+  { 0x0dd7, 0x0e37 }, /*                Thai_sarauee ื THAI CHARACTER SARA UEE */
+  { 0x0dd8, 0x0e38 }, /*                  Thai_sarau ุ THAI CHARACTER SARA U */
+  { 0x0dd9, 0x0e39 }, /*                 Thai_sarauu ู THAI CHARACTER SARA UU */
+  { 0x0dda, 0x0e3a }, /*                Thai_phinthu ฺ THAI CHARACTER PHINTHU */
+  { 0x0dde, 0x0e3e }, /*      Thai_maihanakat_maitho ฾ ??? */
+  { 0x0ddf, 0x0e3f }, /*                   Thai_baht ฿ THAI CURRENCY SYMBOL BAHT */
+  { 0x0de0, 0x0e40 }, /*                  Thai_sarae เ THAI CHARACTER SARA E */
+  { 0x0de1, 0x0e41 }, /*                 Thai_saraae แ THAI CHARACTER SARA AE */
+  { 0x0de2, 0x0e42 }, /*                  Thai_sarao โ THAI CHARACTER SARA O */
+  { 0x0de3, 0x0e43 }, /*          Thai_saraaimaimuan ใ THAI CHARACTER SARA AI MAIMUAN */
+  { 0x0de4, 0x0e44 }, /*         Thai_saraaimaimalai ไ THAI CHARACTER SARA AI MAIMALAI */
+  { 0x0de5, 0x0e45 }, /*            Thai_lakkhangyao ๅ THAI CHARACTER LAKKHANGYAO */
+  { 0x0de6, 0x0e46 }, /*               Thai_maiyamok ๆ THAI CHARACTER MAIYAMOK */
+  { 0x0de7, 0x0e47 }, /*              Thai_maitaikhu ็ THAI CHARACTER MAITAIKHU */
+  { 0x0de8, 0x0e48 }, /*                  Thai_maiek ่ THAI CHARACTER MAI EK */
+  { 0x0de9, 0x0e49 }, /*                 Thai_maitho ้ THAI CHARACTER MAI THO */
+  { 0x0dea, 0x0e4a }, /*                 Thai_maitri ๊ THAI CHARACTER MAI TRI */
+  { 0x0deb, 0x0e4b }, /*            Thai_maichattawa ๋ THAI CHARACTER MAI CHATTAWA */
+  { 0x0dec, 0x0e4c }, /*            Thai_thanthakhat ์ THAI CHARACTER THANTHAKHAT */
+  { 0x0ded, 0x0e4d }, /*               Thai_nikhahit ํ THAI CHARACTER NIKHAHIT */
+  { 0x0df0, 0x0e50 }, /*                 Thai_leksun ๐ THAI DIGIT ZERO */
+  { 0x0df1, 0x0e51 }, /*                Thai_leknung ๑ THAI DIGIT ONE */
+  { 0x0df2, 0x0e52 }, /*                Thai_leksong ๒ THAI DIGIT TWO */
+  { 0x0df3, 0x0e53 }, /*                 Thai_leksam ๓ THAI DIGIT THREE */
+  { 0x0df4, 0x0e54 }, /*                  Thai_leksi ๔ THAI DIGIT FOUR */
+  { 0x0df5, 0x0e55 }, /*                  Thai_lekha ๕ THAI DIGIT FIVE */
+  { 0x0df6, 0x0e56 }, /*                 Thai_lekhok ๖ THAI DIGIT SIX */
+  { 0x0df7, 0x0e57 }, /*                Thai_lekchet ๗ THAI DIGIT SEVEN */
+  { 0x0df8, 0x0e58 }, /*                Thai_lekpaet ๘ THAI DIGIT EIGHT */
+  { 0x0df9, 0x0e59 }, /*                 Thai_lekkao ๙ THAI DIGIT NINE */
+  { 0x0ea1, 0x3131 }, /*               Hangul_Kiyeog ㄱ HANGUL LETTER KIYEOK */
+  { 0x0ea2, 0x3132 }, /*          Hangul_SsangKiyeog ㄲ HANGUL LETTER SSANGKIYEOK */
+  { 0x0ea3, 0x3133 }, /*           Hangul_KiyeogSios ㄳ HANGUL LETTER KIYEOK-SIOS */
+  { 0x0ea4, 0x3134 }, /*                Hangul_Nieun ㄴ HANGUL LETTER NIEUN */
+  { 0x0ea5, 0x3135 }, /*           Hangul_NieunJieuj ㄵ HANGUL LETTER NIEUN-CIEUC */
+  { 0x0ea6, 0x3136 }, /*           Hangul_NieunHieuh ㄶ HANGUL LETTER NIEUN-HIEUH */
+  { 0x0ea7, 0x3137 }, /*               Hangul_Dikeud ㄷ HANGUL LETTER TIKEUT */
+  { 0x0ea8, 0x3138 }, /*          Hangul_SsangDikeud ㄸ HANGUL LETTER SSANGTIKEUT */
+  { 0x0ea9, 0x3139 }, /*                Hangul_Rieul ㄹ HANGUL LETTER RIEUL */
+  { 0x0eaa, 0x313a }, /*          Hangul_RieulKiyeog ㄺ HANGUL LETTER RIEUL-KIYEOK */
+  { 0x0eab, 0x313b }, /*           Hangul_RieulMieum ㄻ HANGUL LETTER RIEUL-MIEUM */
+  { 0x0eac, 0x313c }, /*           Hangul_RieulPieub ㄼ HANGUL LETTER RIEUL-PIEUP */
+  { 0x0ead, 0x313d }, /*            Hangul_RieulSios ㄽ HANGUL LETTER RIEUL-SIOS */
+  { 0x0eae, 0x313e }, /*           Hangul_RieulTieut ㄾ HANGUL LETTER RIEUL-THIEUTH */
+  { 0x0eaf, 0x313f }, /*          Hangul_RieulPhieuf ㄿ HANGUL LETTER RIEUL-PHIEUPH */
+  { 0x0eb0, 0x3140 }, /*           Hangul_RieulHieuh ㅀ HANGUL LETTER RIEUL-HIEUH */
+  { 0x0eb1, 0x3141 }, /*                Hangul_Mieum ㅁ HANGUL LETTER MIEUM */
+  { 0x0eb2, 0x3142 }, /*                Hangul_Pieub ㅂ HANGUL LETTER PIEUP */
+  { 0x0eb3, 0x3143 }, /*           Hangul_SsangPieub ㅃ HANGUL LETTER SSANGPIEUP */
+  { 0x0eb4, 0x3144 }, /*            Hangul_PieubSios ㅄ HANGUL LETTER PIEUP-SIOS */
+  { 0x0eb5, 0x3145 }, /*                 Hangul_Sios ㅅ HANGUL LETTER SIOS */
+  { 0x0eb6, 0x3146 }, /*            Hangul_SsangSios ㅆ HANGUL LETTER SSANGSIOS */
+  { 0x0eb7, 0x3147 }, /*                Hangul_Ieung ㅇ HANGUL LETTER IEUNG */
+  { 0x0eb8, 0x3148 }, /*                Hangul_Jieuj ㅈ HANGUL LETTER CIEUC */
+  { 0x0eb9, 0x3149 }, /*           Hangul_SsangJieuj ㅉ HANGUL LETTER SSANGCIEUC */
+  { 0x0eba, 0x314a }, /*                Hangul_Cieuc ㅊ HANGUL LETTER CHIEUCH */
+  { 0x0ebb, 0x314b }, /*               Hangul_Khieuq ㅋ HANGUL LETTER KHIEUKH */
+  { 0x0ebc, 0x314c }, /*                Hangul_Tieut ㅌ HANGUL LETTER THIEUTH */
+  { 0x0ebd, 0x314d }, /*               Hangul_Phieuf ㅍ HANGUL LETTER PHIEUPH */
+  { 0x0ebe, 0x314e }, /*                Hangul_Hieuh ㅎ HANGUL LETTER HIEUH */
+  { 0x0ebf, 0x314f }, /*                    Hangul_A ㅏ HANGUL LETTER A */
+  { 0x0ec0, 0x3150 }, /*                   Hangul_AE ㅐ HANGUL LETTER AE */
+  { 0x0ec1, 0x3151 }, /*                   Hangul_YA ㅑ HANGUL LETTER YA */
+  { 0x0ec2, 0x3152 }, /*                  Hangul_YAE ㅒ HANGUL LETTER YAE */
+  { 0x0ec3, 0x3153 }, /*                   Hangul_EO ㅓ HANGUL LETTER EO */
+  { 0x0ec4, 0x3154 }, /*                    Hangul_E ㅔ HANGUL LETTER E */
+  { 0x0ec5, 0x3155 }, /*                  Hangul_YEO ㅕ HANGUL LETTER YEO */
+  { 0x0ec6, 0x3156 }, /*                   Hangul_YE ㅖ HANGUL LETTER YE */
+  { 0x0ec7, 0x3157 }, /*                    Hangul_O ㅗ HANGUL LETTER O */
+  { 0x0ec8, 0x3158 }, /*                   Hangul_WA ㅘ HANGUL LETTER WA */
+  { 0x0ec9, 0x3159 }, /*                  Hangul_WAE ㅙ HANGUL LETTER WAE */
+  { 0x0eca, 0x315a }, /*                   Hangul_OE ㅚ HANGUL LETTER OE */
+  { 0x0ecb, 0x315b }, /*                   Hangul_YO ㅛ HANGUL LETTER YO */
+  { 0x0ecc, 0x315c }, /*                    Hangul_U ㅜ HANGUL LETTER U */
+  { 0x0ecd, 0x315d }, /*                  Hangul_WEO ㅝ HANGUL LETTER WEO */
+  { 0x0ece, 0x315e }, /*                   Hangul_WE ㅞ HANGUL LETTER WE */
+  { 0x0ecf, 0x315f }, /*                   Hangul_WI ㅟ HANGUL LETTER WI */
+  { 0x0ed0, 0x3160 }, /*                   Hangul_YU ㅠ HANGUL LETTER YU */
+  { 0x0ed1, 0x3161 }, /*                   Hangul_EU ㅡ HANGUL LETTER EU */
+  { 0x0ed2, 0x3162 }, /*                   Hangul_YI ㅢ HANGUL LETTER YI */
+  { 0x0ed3, 0x3163 }, /*                    Hangul_I ㅣ HANGUL LETTER I */
+  { 0x0ed4, 0x11a8 }, /*             Hangul_J_Kiyeog ᆨ HANGUL JONGSEONG KIYEOK */
+  { 0x0ed5, 0x11a9 }, /*        Hangul_J_SsangKiyeog ᆩ HANGUL JONGSEONG SSANGKIYEOK */
+  { 0x0ed6, 0x11aa }, /*         Hangul_J_KiyeogSios ᆪ HANGUL JONGSEONG KIYEOK-SIOS */
+  { 0x0ed7, 0x11ab }, /*              Hangul_J_Nieun ᆫ HANGUL JONGSEONG NIEUN */
+  { 0x0ed8, 0x11ac }, /*         Hangul_J_NieunJieuj ᆬ HANGUL JONGSEONG NIEUN-CIEUC */
+  { 0x0ed9, 0x11ad }, /*         Hangul_J_NieunHieuh ᆭ HANGUL JONGSEONG NIEUN-HIEUH */
+  { 0x0eda, 0x11ae }, /*             Hangul_J_Dikeud ᆮ HANGUL JONGSEONG TIKEUT */
+  { 0x0edb, 0x11af }, /*              Hangul_J_Rieul ᆯ HANGUL JONGSEONG RIEUL */
+  { 0x0edc, 0x11b0 }, /*        Hangul_J_RieulKiyeog ᆰ HANGUL JONGSEONG RIEUL-KIYEOK */
+  { 0x0edd, 0x11b1 }, /*         Hangul_J_RieulMieum ᆱ HANGUL JONGSEONG RIEUL-MIEUM */
+  { 0x0ede, 0x11b2 }, /*         Hangul_J_RieulPieub ᆲ HANGUL JONGSEONG RIEUL-PIEUP */
+  { 0x0edf, 0x11b3 }, /*          Hangul_J_RieulSios ᆳ HANGUL JONGSEONG RIEUL-SIOS */
+  { 0x0ee0, 0x11b4 }, /*         Hangul_J_RieulTieut ᆴ HANGUL JONGSEONG RIEUL-THIEUTH */
+  { 0x0ee1, 0x11b5 }, /*        Hangul_J_RieulPhieuf ᆵ HANGUL JONGSEONG RIEUL-PHIEUPH */
+  { 0x0ee2, 0x11b6 }, /*         Hangul_J_RieulHieuh ᆶ HANGUL JONGSEONG RIEUL-HIEUH */
+  { 0x0ee3, 0x11b7 }, /*              Hangul_J_Mieum ᆷ HANGUL JONGSEONG MIEUM */
+  { 0x0ee4, 0x11b8 }, /*              Hangul_J_Pieub ᆸ HANGUL JONGSEONG PIEUP */
+  { 0x0ee5, 0x11b9 }, /*          Hangul_J_PieubSios ᆹ HANGUL JONGSEONG PIEUP-SIOS */
+  { 0x0ee6, 0x11ba }, /*               Hangul_J_Sios ᆺ HANGUL JONGSEONG SIOS */
+  { 0x0ee7, 0x11bb }, /*          Hangul_J_SsangSios ᆻ HANGUL JONGSEONG SSANGSIOS */
+  { 0x0ee8, 0x11bc }, /*              Hangul_J_Ieung ᆼ HANGUL JONGSEONG IEUNG */
+  { 0x0ee9, 0x11bd }, /*              Hangul_J_Jieuj ᆽ HANGUL JONGSEONG CIEUC */
+  { 0x0eea, 0x11be }, /*              Hangul_J_Cieuc ᆾ HANGUL JONGSEONG CHIEUCH */
+  { 0x0eeb, 0x11bf }, /*             Hangul_J_Khieuq ᆿ HANGUL JONGSEONG KHIEUKH */
+  { 0x0eec, 0x11c0 }, /*              Hangul_J_Tieut ᇀ HANGUL JONGSEONG THIEUTH */
+  { 0x0eed, 0x11c1 }, /*             Hangul_J_Phieuf ᇁ HANGUL JONGSEONG PHIEUPH */
+  { 0x0eee, 0x11c2 }, /*              Hangul_J_Hieuh ᇂ HANGUL JONGSEONG HIEUH */
+  { 0x0eef, 0x316d }, /*     Hangul_RieulYeorinHieuh ㅭ HANGUL LETTER RIEUL-YEORINHIEUH */
+  { 0x0ef0, 0x3171 }, /*    Hangul_SunkyeongeumMieum ㅱ HANGUL LETTER KAPYEOUNMIEUM */
+  { 0x0ef1, 0x3178 }, /*    Hangul_SunkyeongeumPieub ㅸ HANGUL LETTER KAPYEOUNPIEUP */
+  { 0x0ef2, 0x317f }, /*              Hangul_PanSios ㅿ HANGUL LETTER PANSIOS */
+/*  0x0ef3                  Hangul_KkogjiDalrinIeung ? ??? */
+  { 0x0ef4, 0x3184 }, /*   Hangul_SunkyeongeumPhieuf ㆄ HANGUL LETTER KAPYEOUNPHIEUPH */
+  { 0x0ef5, 0x3186 }, /*          Hangul_YeorinHieuh ㆆ HANGUL LETTER YEORINHIEUH */
+  { 0x0ef6, 0x318d }, /*                Hangul_AraeA ㆍ HANGUL LETTER ARAEA */
+  { 0x0ef7, 0x318e }, /*               Hangul_AraeAE ㆎ HANGUL LETTER ARAEAE */
+  { 0x0ef8, 0x11eb }, /*            Hangul_J_PanSios ᇫ HANGUL JONGSEONG PANSIOS */
+/*  0x0ef9                Hangul_J_KkogjiDalrinIeung ? ??? */
+  { 0x0efa, 0x11f9 }, /*        Hangul_J_YeorinHieuh ᇹ HANGUL JONGSEONG YEORINHIEUH */
+  { 0x0eff, 0x20a9 }, /*                  Korean_Won ₩ WON SIGN */
+  { 0x13bc, 0x0152 }, /*                          OE ΠLATIN CAPITAL LIGATURE OE */
+  { 0x13bd, 0x0153 }, /*                          oe œ LATIN SMALL LIGATURE OE */
+  { 0x13be, 0x0178 }, /*                  Ydiaeresis Ÿ LATIN CAPITAL LETTER Y WITH DIAERESIS */
+  { 0x20a0, 0x20a0 }, /*                     EcuSign ₠ EURO-CURRENCY SIGN */
+  { 0x20a1, 0x20a1 }, /*                   ColonSign ₡ COLON SIGN */
+  { 0x20a2, 0x20a2 }, /*                CruzeiroSign ₢ CRUZEIRO SIGN */
+  { 0x20a3, 0x20a3 }, /*                  FFrancSign ₣ FRENCH FRANC SIGN */
+  { 0x20a4, 0x20a4 }, /*                    LiraSign ₤ LIRA SIGN */
+  { 0x20a5, 0x20a5 }, /*                    MillSign ₥ MILL SIGN */
+  { 0x20a6, 0x20a6 }, /*                   NairaSign ₦ NAIRA SIGN */
+  { 0x20a7, 0x20a7 }, /*                  PesetaSign ₧ PESETA SIGN */
+  { 0x20a8, 0x20a8 }, /*                   RupeeSign ₨ RUPEE SIGN */
+  { 0x20a9, 0x20a9 }, /*                     WonSign ₩ WON SIGN */
+  { 0x20aa, 0x20aa }, /*               NewSheqelSign ₪ NEW SHEQEL SIGN */
+  { 0x20ab, 0x20ab }, /*                    DongSign ₫ DONG SIGN */
+  { 0x20ac, 0x20ac }, /*                    EuroSign € EURO SIGN */
+    // clang-format on
+};
+
+long keysym2ucs(KeySym keysym) {
+  int min = 0;
+  int max = sizeof(keysymtab) / sizeof(struct codepair) - 1;
+  int mid;
+
+  /* first check for Latin-1 characters (1:1 mapping) */
+  if ((keysym >= 0x0020 && keysym <= 0x007e) ||
+      (keysym >= 0x00a0 && keysym <= 0x00ff))
+    return keysym;
+
+  /* also check for directly encoded 24-bit UCS characters */
+  if ((keysym & 0xff000000) == 0x01000000) return keysym & 0x00ffffff;
+
+  /* binary search in table */
+  while (max >= min) {
+    mid = (min + max) / 2;
+    if (keysymtab[mid].keysym < keysym)
+      min = mid + 1;
+    else if (keysymtab[mid].keysym > keysym)
+      max = mid - 1;
+    else {
+      /* found it */
+      return keysymtab[mid].ucs;
+    }
+  }
+
+  /* no matching Unicode value found */
+  return -1;
+}
diff --git a/widget/x11/keysym2ucs.h b/widget/x11/keysym2ucs.h
new file mode 100644
index 0000000000..b081e27605
--- /dev/null
+++ b/widget/x11/keysym2ucs.h
@@ -0,0 +1,28 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/*
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+/*
+ * This module converts keysym values into the corresponding ISO 10646-1
+ * (UCS, Unicode) values.
+ */
+
+#ifdef MOZ_X11
+#  include <X11/X.h>
+#else
+#  define KeySym unsigned int
+#endif /* MOZ_X11 */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+long keysym2ucs(KeySym keysym);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
diff --git a/widget/x11/moz.build b/widget/x11/moz.build
new file mode 100644
index 0000000000..81d345c0af
--- /dev/null
+++ b/widget/x11/moz.build
@@ -0,0 +1,16 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "Widget: Gtk")
+
+SOURCES += [
+    "keysym2ucs.c",
+]
+
+FINAL_LIBRARY = "xul"
+
+CFLAGS += CONFIG["MOZ_X11_CFLAGS"]